changelog

* add lc flag check to rpc handlers

* deps

* changelog

* update tests

* deps

CHANGELOG.md

@@ -4,7 +4,52 @@ All notable changes to this project will be documented in this file.
 
 The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.
 
-## [Unreleased](https://github.com/prysmaticlabs/prysm/compare/v5.1.2...HEAD)
+## [Unreleased](https://github.com/prysmaticlabs/prysm/compare/v5.2.0...HEAD)
+
+### Added
+
+- Added proper gas limit check for header from the builder.
+- Added an error field to log `Finished building block`.
+- Implemented a new `EmptyExecutionPayloadHeader` function.
+- `Finished building block`: Display error only if not nil.
+- Return an error instead of panic when invalidating the finalized checkpoint.
+
+### Changed
+
+- Process light client finality updates only for new finalized epochs instead of doing it for every block.
+- Refactor subnets subscriptions.
+- Refactor RPC handlers subscriptions.
+
+### Deprecated
+
+
+### Removed
+
+
+### Fixed
+
+- Added check to prevent nil pointer deference or out of bounds array access when validating the BLSToExecutionChange on an impossibly nil validator.
+
+### Security
+
+
+## [v5.2.0](https://github.com/prysmaticlabs/prysm/compare/v5.1.2...v5.2.0)
+
+Updating to this release is highly recommended, especially for users running v5.1.1 or v5.1.2.
+This release is **mandatory** for all validator clients using mev-boost with a gas limit increase.
+Without upgrading to this release, validator clients will default to using local execution blocks
+when the gas limit starts to increase.
+
+This release has several fixes and new features. In this release, we have enabled QUIC protocol by
+default, which uses port 13000 for `--p2p-quic-port`. This may be a [breaking change](https://github.com/prysmaticlabs/prysm/pull/14688#issuecomment-2516713826)
+if you're using port 13000 already. This release has some improvements for raising the gas limit,
+but there are [known issues](https://hackmd.io/@ttsao/prysm-gas-limit) with the proposer settings
+file provided gas limit not being respected for mev-boost outsourced blocks. Signalling an increase
+for the gas limit works perfectly for local block production as of this release. See [pumpthegas.org](https://pumpthegas.org) for more info on raising the gas limit on L1.
+
+Notable features:
+- Prysm can reuse blobs from the EL via engine_getBlobsV1, [potentially saving bandwidth](https://hackmd.io/@ttsao/get-blobs-early-results).
+- QUIC is enabled by default. This is a UDP based networking protocol with default port 13000.
 
 ### Added
 
@@ -29,6 +74,11 @@ The format is based on Keep a Changelog, and this project adheres to Semantic Ve
 - PeerDAS: Added proto for `DataColumnIdentifier`, `DataColumnSidecar`, `DataColumnSidecarsByRangeRequest` and `MetadataV2`.
 - Better attestation packing for Electra. [PR](https://github.com/prysmaticlabs/prysm/pull/14534)
 - P2P: Add logs when a peer is (dis)connected. Add the reason of the disconnection when we initiate it.
+- Added a Prometheus error counter metric for HTTP requests to track beacon node requests.
+- Added a Prometheus error counter metric for SSE requests.
+- Save light client updates and bootstraps in DB.
+- Added more comprehensive tests for `BlockToLightClientHeader`. [PR](https://github.com/prysmaticlabs/prysm/pull/14699)
+- Added light client feature flag check to RPC handlers. [PR](https://github.com/prysmaticlabs/prysm/pull/14736)
 
 ### Changed
 
@@ -63,18 +113,28 @@ The format is based on Keep a Changelog, and this project adheres to Semantic Ve
 - Updated light client protobufs. [PR](https://github.com/prysmaticlabs/prysm/pull/14650)
 - Added `Eth-Consensus-Version` header to `ListAttestationsV2` and `GetAggregateAttestationV2` endpoints.
 - Updated light client consensus types. [PR](https://github.com/prysmaticlabs/prysm/pull/14652)
+- Update earliest exit epoch for upgrade to electra
+- Add missed exit checks to consolidation processing
 - Fixed pending deposits processing on Electra.
 - Modified `ListAttestationsV2`, `GetAttesterSlashingsV2` and `GetAggregateAttestationV2` endpoints to use slot to determine fork version.
+- Improvements to HTTP response handling. [pr](https://github.com/prysmaticlabs/prysm/pull/14673)
+- Updated `Blobs` endpoint to return additional metadata fields.
+- Made QUIC the default method to connect with peers.
+- Check kzg commitments align with blobs and proofs for beacon api end point.
+- Revert "Proposer checks gas limit before accepting builder's bid".
+- Updated quic-go to v0.48.2 .
 
 ### Deprecated
 
 - `/eth/v1alpha1/validator/activation/stream` grpc wait for activation stream is deprecated. [pr](https://github.com/prysmaticlabs/prysm/pull/14514)
+- `--interop-genesis-time` and `--interop-num-validators` have been deprecated in the beacon node as the functionality has been removed. These flags have no effect.
 
 ### Removed
 
 - Removed finalized validator index cache, no longer needed.
 - Removed validator queue position log on key reload and wait for activation.
 - Removed outdated spectest exclusions for EIP-6110.
+- Removed support for starting a beacon node with a deterministic interop genesis state via interop flags. Alteratively, create a genesis state with prysmctl and use `--genesis-state`. This removes about 9Mb (~11%) of unnecessary code and dependencies from the final production binary.
 - Removed kzg proof check from blob reconstructor.
 
 ### Fixed
@@ -96,7 +156,14 @@ The format is based on Keep a Changelog, and this project adheres to Semantic Ve
 - corrects nil check on some interface attestation types
 - temporary solution to handling electra attesation and attester_slashing events. [pr](14655)
 - Diverse log improvements and comment additions.
-
+- Validate that each committee bitfield in an aggregate contains at least one non-zero bit
+- P2P: Avoid infinite loop when looking for peers in small networks.
+- Fixed another rollback bug due to a context deadline.
+- Fix checkpoint sync bug on holesky. [pr](https://github.com/prysmaticlabs/prysm/pull/14689)
+- Fix proposer boost spec tests being flakey by adjusting start time from 3 to 2s into slot.
+- Fix segmentation fault in E2E when light-client feature flag is enabled. [PR](https://github.com/prysmaticlabs/prysm/pull/14699)
+- Fix `searchForPeers` infinite loop in small networks.
+- Fix slashing pool behavior to enforce MaxAttesterSlashings limit in Electra version.
 
 ### Security
 
@@ -421,6 +488,7 @@ block profit. If you want to preserve the existing behavior, set --local-block-v
 - Set default LocalBlockValueBoost to 10
 - Add bid value metrics
 - REST VC metrics
+- `startDB`: Add log when checkpoint sync.
 
 ### Changed
 

INTEROP.md

@@ -2,18 +2,21 @@
 
 This README details how to setup Prysm for interop testing for usage with other Ethereum consensus clients.
 
+> [!IMPORTANT]  
+> This guide is likely to be outdated. The Prysm team does not have capacity to troubleshoot
+> outdated interop guides or instructions. If you experience issues with this guide, please file and
+> issue for visibility and propose fixes, if possible.
+
 ## Installation & Setup
 
 1. Install [Bazel](https://docs.bazel.build/versions/master/install.html) **(Recommended)**
 2. `git clone https://github.com/prysmaticlabs/prysm && cd prysm`
-3. `bazel build //...`
+3. `bazel build //cmd/...`
 
 ## Starting from Genesis
 
-Prysm supports a few ways to quickly launch a beacon node from basic configurations:
-
-- `NumValidators + GenesisTime`: Launches a beacon node by deterministically generating a state from a num-validators flag along with a genesis time **(Recommended)**
-- `SSZ Genesis`: Launches a beacon node  from a .ssz file containing a SSZ-encoded, genesis beacon state
+Prysm can be started from a built-in mainnet genesis state, or started with a provided genesis state by
+using the `--genesis-state` flag and providing a path to the genesis.ssz file.
 
 ## Generating a Genesis State
 
@@ -21,21 +24,34 @@ To setup the necessary files for these quick starts, Prysm provides a tool to ge
 a deterministically generated set of validator private keys following the official interop YAML format 
 [here](https://github.com/ethereum/eth2.0-pm/blob/master/interop/mocked_start).
 
-You can use `bazel run //tools/genesis-state-gen` to create a deterministic genesis state for interop.
+You can use `prysmctl` to create a deterministic genesis state for interop.
 
-### Usage
-
-- **--genesis-time** uint: Unix timestamp used as the genesis time in the generated genesis state (defaults to now)
-- **--num-validators** int: Number of validators to deterministically include in the generated genesis state
-- **--output-ssz** string: Output filename of the SSZ marshaling of the generated genesis state
-- **--config-name=interop** string: name of the beacon chain config to use when generating the state. ex mainnet|minimal|interop
-
-The example below creates 64 validator keys, instantiates a genesis state with those 64 validators and with genesis unix timestamp 1567542540,
-and finally writes a ssz encoded output to ~/Desktop/genesis.ssz. This file can be used to kickstart the beacon chain in the next section. When using the `--interop-*` flags, the beacon node will assume the `interop` config should be used, unless a different config is specified on the command line.
+```sh
+# Download (or create) a chain config file.
+curl https://raw.githubusercontent.com/ethereum/consensus-specs/refs/heads/dev/configs/minimal.yaml -o /tmp/minimal.yaml
 
+# Run prysmctl to generate genesis with a 2 minute genesis delay and 256 validators. 
+bazel run //cmd/prysmctl --config=minimal -- \
+  testnet generate-genesis \
+  --genesis-time-delay=120 \
+  --num-validators=256 \
+  --output-ssz=/tmp/genesis.ssz \
+  --chain-config-file=/tmp/minimal.yaml
 ```
-bazel run //tools/genesis-state-gen -- --config-name interop --output-ssz ~/Desktop/genesis.ssz --num-validators 64 --genesis-time 1567542540
-```
+
+The flags are explained below:
+- `bazel run //cmd/prysmctl` is the bazel command to compile and run prysmctl.
+- `--config=minimal` is a bazel build time configuration flag to compile Prysm with minimal state constants.
+- `--` is an argument divider to tell bazel that everything after this divider should be passed as arguments to prysmctl. Without this divider, it isn't clear to bazel if the arguments are meant to be build time arguments or runtime arguments so the operation complains and fails to build without this divider.
+- `testnet` is the primary command argument for prysmctl.
+- `generate-genesis` is the subcommand to `testnet` in prysmctl.
+- `--genesis-time-delay` uint: The number of seconds in the future to define genesis. Example: a value of 60 will set the genesis time to 1 minute in the future. This should be sufficiently large enough to allow for you to start the beacon node before the genesis time. 
+- `--num-validators` int: Number of validators to deterministically include in the generated genesis state
+- `--output-ssz` string: Output filename of the SSZ marshaling of the generated genesis state
+- `--chain-config-file` string: Filepath to a chain config yaml file.
+
+Note: This guide saves items to the `/tmp/` directory which will not persist if your machine is
+restarted. Consider tweaking the arguments if persistence is needed.
 
 ## Launching a Beacon Node + Validator Client
 
@@ -44,45 +60,33 @@ bazel run //tools/genesis-state-gen -- --config-name interop --output-ssz ~/Desk
 Open up two terminal windows, run:
 
 ```
-bazel run //beacon-chain -- \
---bootstrap-node= \
---deposit-contract 0x8A04d14125D0FDCDc742F4A05C051De07232EDa4 \
---datadir=/tmp/beacon-chain-interop \
---force-clear-db \
---min-sync-peers=0 \
---interop-num-validators 64 \
---interop-eth1data-votes
+bazel run //cmd/beacon-chain --config=minimal -- \
+  --minimal-config \
+  --bootstrap-node= \
+  --deposit-contract 0x8A04d14125D0FDCDc742F4A05C051De07232EDa4 \
+  --datadir=/tmp/beacon-chain-minimal-devnet \
+  --force-clear-db \
+  --min-sync-peers=0 \
+  --genesis-state=/tmp/genesis.ssz \
+  --chain-config-file=/tmp/minimal.yaml
 ```
 
-This will deterministically generate a beacon genesis state and start
-the system with 64 validators and the genesis time set to the current unix timestamp.
-Wait a bit until your beacon chain starts, and in the other window:
+This will start the system with 256 validators. The flags used can be explained as such:
+
+- `bazel run //cmd/beacon-chain --config=minimal` builds and runs the beacon node in minimal build configuration.
+- `--` is a flag divider to distingish between bazel flags and flags that should be passed to the application. All flags and arguments after this divider are passed to the beacon chain.
+- `--minimal-config` tells the beacon node to use minimal network configuration. This is different from the compile time state configuration flag `--config=minimal` and both are required.
+- `--bootstrap-node=` disables the default bootstrap nodes. This prevents the client from attempting to peer with mainnet nodes.
+- `--datadir=/tmp/beacon-chain-minimal-devnet` sets the data directory in a temporary location. Change this to your preferred destination.
+- `--force-clear-db` will delete the beaconchain.db file without confirming with the user. This is helpful for iteratively running local devnets without changing the datadir, but less helpful for one off runs where there was no database in the data directory.
+- `--min-sync-peers=0` allows the beacon node to skip initial sync without peers. This is essential because Prysm expects at least a few peers to start start the blockchain.
+- `--genesis-state=/tmp/genesis.ssz` defines the path to the generated genesis ssz file. The beacon node will use this as the initial genesis state.
+- `--chain-config-file=/tmp/minimal.yaml` defines the path to the yaml file with the chain configuration.
+
+As soon as the beacon node has started, start the validator in the other terminal window. 
 
 ```
-bazel run //validator -- --keymanager=interop --keymanageropts='{"keys":64}'
+bazel run //cmd/validator --config=minimal -- --datadir=/tmp/validator --interopt-num-validators=256 --minimal-config --suggested-fee-recipient=0x8A04d14125D0FDCDc742F4A05C051De07232EDa4
 ```
 
-This will launch and kickstart the system with your 64 validators performing their duties accordingly.
-
-### Launching from `genesis.ssz`
-
-Assuming you generated a `genesis.ssz` file with 64 validators, open up two terminal windows, run:
-
-```
- bazel run //beacon-chain -- \
---bootstrap-node= \
---deposit-contract 0x8A04d14125D0FDCDc742F4A05C051De07232EDa4 \
---datadir=/tmp/beacon-chain-interop \
---force-clear-db \
---min-sync-peers=0 \
---interop-genesis-state /path/to/genesis.ssz \
---interop-eth1data-votes
-```
-
-Wait a bit until your beacon chain starts, and in the other window:
-
-```
-bazel run //validator -- --keymanager=interop --keymanageropts='{"keys":64}'
-```
-
-This will launch and kickstart the system with your 64 validators performing their duties accordingly.
+This will launch and kickstart the system with your 256 validators performing their duties accordingly.

WORKSPACE

@@ -227,7 +227,7 @@ filegroup(
     url = "https://github.com/ethereum/EIPs/archive/5480440fe51742ed23342b68cf106cefd427e39d.tar.gz",
 )
 
-consensus_spec_version = "v1.5.0-alpha.8"
+consensus_spec_version = "v1.5.0-alpha.9"
 
 bls_test_version = "v0.1.1"
 
@@ -243,7 +243,7 @@ filegroup(
     visibility = ["//visibility:public"],
 )
     """,
-    integrity = "sha256-BsGIbEyJuYrzhShGl0tHhR4lP5Qwno8R3k8a6YBR/DA=",
+    integrity = "sha256-gHbvlnErUeJGWzW8/8JiVlk28JwmXSMhOzkynEIz+8g=",
     url = "https://github.com/ethereum/consensus-spec-tests/releases/download/%s/general.tar.gz" % consensus_spec_version,
 )
 
@@ -259,7 +259,7 @@ filegroup(
     visibility = ["//visibility:public"],
 )
     """,
-    integrity = "sha256-DkdvhPP2KiqUOpwFXQIFDCWCwsUDIC/xhTBD+TZevm0=",
+    integrity = "sha256-hQkQdpm5ng4miGYa5WsOKWa0q8WtZu99Oqbv9QtBeJM=",
     url = "https://github.com/ethereum/consensus-spec-tests/releases/download/%s/minimal.tar.gz" % consensus_spec_version,
 )
 
@@ -275,7 +275,7 @@ filegroup(
     visibility = ["//visibility:public"],
 )
     """,
-    integrity = "sha256-vkZqV0HB8A2Uc56C1Us/p5G57iaHL+zw2No93Xt6M/4=",
+    integrity = "sha256-33sBsmApnJpcyYfR3olKaPB+WC1q00ZKNzHa2TczIxk=",
     url = "https://github.com/ethereum/consensus-spec-tests/releases/download/%s/mainnet.tar.gz" % consensus_spec_version,
 )
 
@@ -290,7 +290,7 @@ filegroup(
     visibility = ["//visibility:public"],
 )
     """,
-    integrity = "sha256-D/HPAW61lKqjoWwl7N0XvhdX+67dCEFAy8JxVzqBGtU=",
+    integrity = "sha256-GQulBKLc2khpql2K/MxV+NG/d2kAhLXl+gLnKIg7rt4=",
     strip_prefix = "consensus-specs-" + consensus_spec_version[1:],
     url = "https://github.com/ethereum/consensus-specs/archive/refs/tags/%s.tar.gz" % consensus_spec_version,
 )

api/client/builder/BUILD.bazel

@@ -12,6 +12,7 @@ go_library(
     visibility = ["//visibility:public"],
     deps = [
         "//api:go_default_library",
+        "//api/client:go_default_library",
         "//api/server/structs:go_default_library",
         "//config/fieldparams:go_default_library",
         "//consensus-types:go_default_library",

api/client/builder/client.go

@@ -14,6 +14,7 @@ import (
 
 	"github.com/pkg/errors"
 	"github.com/prysmaticlabs/prysm/v5/api"
+	"github.com/prysmaticlabs/prysm/v5/api/client"
 	"github.com/prysmaticlabs/prysm/v5/api/server/structs"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/interfaces"
@@ -176,7 +177,7 @@ func (c *Client) do(ctx context.Context, method string, path string, body io.Rea
 		err = non200Err(r)
 		return
 	}
-	res, err = io.ReadAll(r.Body)
+	res, err = io.ReadAll(io.LimitReader(r.Body, client.MaxBodySize))
 	if err != nil {
 		err = errors.Wrap(err, "error reading http response body from builder server")
 		return
@@ -358,7 +359,7 @@ func (c *Client) Status(ctx context.Context) error {
 }
 
 func non200Err(response *http.Response) error {
-	bodyBytes, err := io.ReadAll(response.Body)
+	bodyBytes, err := io.ReadAll(io.LimitReader(response.Body, client.MaxErrBodySize))
 	var errMessage ErrorMessage
 	var body string
 	if err != nil {

api/client/client.go

@@ -10,11 +10,18 @@ import (
 	"github.com/pkg/errors"
 )
 
+const (
+	MaxBodySize      int64 = 1 << 23 // 8MB default, WithMaxBodySize can override
+	MaxBodySizeState int64 = 1 << 29 // 512MB
+	MaxErrBodySize   int64 = 1 << 17 // 128KB
+)
+
 // Client is a wrapper object around the HTTP client.
 type Client struct {
-	hc      *http.Client
-	baseURL *url.URL
-	token   string
+	hc          *http.Client
+	baseURL     *url.URL
+	token       string
+	maxBodySize int64
 }
 
 // NewClient constructs a new client with the provided options (ex WithTimeout).
@@ -26,8 +33,9 @@ func NewClient(host string, opts ...ClientOpt) (*Client, error) {
 		return nil, err
 	}
 	c := &Client{
-		hc:      &http.Client{},
-		baseURL: u,
+		hc:          &http.Client{},
+		baseURL:     u,
+		maxBodySize: MaxBodySize,
 	}
 	for _, o := range opts {
 		o(c)
@@ -72,7 +80,7 @@ func (c *Client) NodeURL() string {
 // Get is a generic, opinionated GET function to reduce boilerplate amongst the getters in this package.
 func (c *Client) Get(ctx context.Context, path string, opts ...ReqOption) ([]byte, error) {
 	u := c.baseURL.ResolveReference(&url.URL{Path: path})
-	req, err := http.NewRequestWithContext(ctx, http.MethodGet, u.String(), nil)
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, u.String(), http.NoBody)
 	if err != nil {
 		return nil, err
 	}
@@ -89,7 +97,7 @@ func (c *Client) Get(ctx context.Context, path string, opts ...ReqOption) ([]byt
 	if r.StatusCode != http.StatusOK {
 		return nil, Non200Err(r)
 	}
-	b, err := io.ReadAll(r.Body)
+	b, err := io.ReadAll(io.LimitReader(r.Body, c.maxBodySize))
 	if err != nil {
 		return nil, errors.Wrap(err, "error reading http response body")
 	}

api/client/errors.go

@@ -25,16 +25,16 @@ var ErrInvalidNodeVersion = errors.New("invalid node version response")
 var ErrConnectionIssue = errors.New("could not connect")
 
 // Non200Err is a function that parses an HTTP response to handle responses that are not 200 with a formatted error.
-func Non200Err(response *http.Response) error {
-	bodyBytes, err := io.ReadAll(response.Body)
+func Non200Err(r *http.Response) error {
+	b, err := io.ReadAll(io.LimitReader(r.Body, MaxErrBodySize))
 	var body string
 	if err != nil {
 		body = "(Unable to read response body.)"
 	} else {
-		body = "response body:\n" + string(bodyBytes)
+		body = "response body:\n" + string(b)
 	}
-	msg := fmt.Sprintf("code=%d, url=%s, body=%s", response.StatusCode, response.Request.URL, body)
-	switch response.StatusCode {
+	msg := fmt.Sprintf("code=%d, url=%s, body=%s", r.StatusCode, r.Request.URL, body)
+	switch r.StatusCode {
 	case http.StatusNotFound:
 		return errors.Wrap(ErrNotFound, msg)
 	default:

api/client/options.go

@@ -46,3 +46,10 @@ func WithAuthenticationToken(token string) ClientOpt {
 		c.token = token
 	}
 }
+
+// WithMaxBodySize overrides the default max body size of 8MB.
+func WithMaxBodySize(size int64) ClientOpt {
+	return func(c *Client) {
+		c.maxBodySize = size
+	}
+}

api/server/structs/BUILD.bazel

@@ -36,9 +36,8 @@ go_library(
         "//math:go_default_library",
         "//proto/engine/v1:go_default_library",
         "//proto/eth/v1:go_default_library",
-        "//proto/eth/v2:go_default_library",
-        "//proto/migration:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
+        "//runtime/version:go_default_library",
         "@com_github_ethereum_go_ethereum//common:go_default_library",
         "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
         "@com_github_pkg_errors//:go_default_library",

api/server/structs/conversions.go

@@ -1546,3 +1546,10 @@ func EventChainReorgFromV1(event *ethv1.EventChainReorg) *ChainReorgEvent {
 		ExecutionOptimistic: event.ExecutionOptimistic,
 	}
 }
+
+func SyncAggregateFromConsensus(sa *eth.SyncAggregate) *SyncAggregate {
+	return &SyncAggregate{
+		SyncCommitteeBits:      hexutil.Encode(sa.SyncCommitteeBits),
+		SyncCommitteeSignature: hexutil.Encode(sa.SyncCommitteeSignature),
+	}
+}

api/server/structs/conversions_lightclient.go

@@ -3,125 +3,227 @@ package structs
 import (
 	"encoding/json"
 	"fmt"
-	"strconv"
 
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/pkg/errors"
-	v1 "github.com/prysmaticlabs/prysm/v5/proto/eth/v1"
-	v2 "github.com/prysmaticlabs/prysm/v5/proto/eth/v2"
-	"github.com/prysmaticlabs/prysm/v5/proto/migration"
+	"github.com/prysmaticlabs/prysm/v5/consensus-types/interfaces"
+	enginev1 "github.com/prysmaticlabs/prysm/v5/proto/engine/v1"
+	"github.com/prysmaticlabs/prysm/v5/runtime/version"
 )
 
-func LightClientUpdateFromConsensus(update *v2.LightClientUpdate) (*LightClientUpdate, error) {
-	attestedHeader, err := lightClientHeaderContainerToJSON(update.AttestedHeader)
+func LightClientUpdateFromConsensus(update interfaces.LightClientUpdate) (*LightClientUpdate, error) {
+	attestedHeader, err := lightClientHeaderToJSON(update.AttestedHeader())
 	if err != nil {
 		return nil, errors.Wrap(err, "could not marshal attested light client header")
 	}
-	finalizedHeader, err := lightClientHeaderContainerToJSON(update.FinalizedHeader)
+	finalizedHeader, err := lightClientHeaderToJSON(update.FinalizedHeader())
 	if err != nil {
 		return nil, errors.Wrap(err, "could not marshal finalized light client header")
 	}
 
+	var scBranch [][32]byte
+	var finalityBranch [][32]byte
+	if update.Version() >= version.Electra {
+		scb, err := update.NextSyncCommitteeBranchElectra()
+		if err != nil {
+			return nil, err
+		}
+		scBranch = scb[:]
+		fb, err := update.FinalityBranchElectra()
+		if err != nil {
+			return nil, err
+		}
+		finalityBranch = fb[:]
+	} else {
+		scb, err := update.NextSyncCommitteeBranch()
+		if err != nil {
+			return nil, err
+		}
+		scBranch = scb[:]
+		fb, err := update.FinalityBranch()
+		if err != nil {
+			return nil, err
+		}
+		finalityBranch = fb[:]
+	}
+
 	return &LightClientUpdate{
 		AttestedHeader:          attestedHeader,
-		NextSyncCommittee:       SyncCommitteeFromConsensus(migration.V2SyncCommitteeToV1Alpha1(update.NextSyncCommittee)),
-		NextSyncCommitteeBranch: branchToJSON(update.NextSyncCommitteeBranch),
+		NextSyncCommittee:       SyncCommitteeFromConsensus(update.NextSyncCommittee()),
+		NextSyncCommitteeBranch: branchToJSON(scBranch),
 		FinalizedHeader:         finalizedHeader,
-		FinalityBranch:          branchToJSON(update.FinalityBranch),
-		SyncAggregate:           syncAggregateToJSON(update.SyncAggregate),
-		SignatureSlot:           strconv.FormatUint(uint64(update.SignatureSlot), 10),
+		FinalityBranch:          branchToJSON(finalityBranch),
+		SyncAggregate:           SyncAggregateFromConsensus(update.SyncAggregate()),
+		SignatureSlot:           fmt.Sprintf("%d", update.SignatureSlot()),
 	}, nil
 }
 
-func LightClientFinalityUpdateFromConsensus(update *v2.LightClientFinalityUpdate) (*LightClientFinalityUpdate, error) {
-	attestedHeader, err := lightClientHeaderContainerToJSON(update.AttestedHeader)
+func LightClientFinalityUpdateFromConsensus(update interfaces.LightClientFinalityUpdate) (*LightClientFinalityUpdate, error) {
+	attestedHeader, err := lightClientHeaderToJSON(update.AttestedHeader())
 	if err != nil {
 		return nil, errors.Wrap(err, "could not marshal attested light client header")
 	}
-	finalizedHeader, err := lightClientHeaderContainerToJSON(update.FinalizedHeader)
+	finalizedHeader, err := lightClientHeaderToJSON(update.FinalizedHeader())
 	if err != nil {
 		return nil, errors.Wrap(err, "could not marshal finalized light client header")
 	}
 
+	var finalityBranch [][32]byte
+	if update.Version() >= version.Electra {
+		b, err := update.FinalityBranchElectra()
+		if err != nil {
+			return nil, err
+		}
+		finalityBranch = b[:]
+	} else {
+		b, err := update.FinalityBranch()
+		if err != nil {
+			return nil, err
+		}
+		finalityBranch = b[:]
+	}
+
 	return &LightClientFinalityUpdate{
 		AttestedHeader:  attestedHeader,
 		FinalizedHeader: finalizedHeader,
-		FinalityBranch:  branchToJSON(update.FinalityBranch),
-		SyncAggregate:   syncAggregateToJSON(update.SyncAggregate),
-		SignatureSlot:   strconv.FormatUint(uint64(update.SignatureSlot), 10),
+		FinalityBranch:  branchToJSON(finalityBranch),
+		SyncAggregate:   SyncAggregateFromConsensus(update.SyncAggregate()),
+		SignatureSlot:   fmt.Sprintf("%d", update.SignatureSlot()),
 	}, nil
 }
 
-func LightClientOptimisticUpdateFromConsensus(update *v2.LightClientOptimisticUpdate) (*LightClientOptimisticUpdate, error) {
-	attestedHeader, err := lightClientHeaderContainerToJSON(update.AttestedHeader)
+func LightClientOptimisticUpdateFromConsensus(update interfaces.LightClientOptimisticUpdate) (*LightClientOptimisticUpdate, error) {
+	attestedHeader, err := lightClientHeaderToJSON(update.AttestedHeader())
 	if err != nil {
 		return nil, errors.Wrap(err, "could not marshal attested light client header")
 	}
 
 	return &LightClientOptimisticUpdate{
 		AttestedHeader: attestedHeader,
-		SyncAggregate:  syncAggregateToJSON(update.SyncAggregate),
-		SignatureSlot:  strconv.FormatUint(uint64(update.SignatureSlot), 10),
+		SyncAggregate:  SyncAggregateFromConsensus(update.SyncAggregate()),
+		SignatureSlot:  fmt.Sprintf("%d", update.SignatureSlot()),
 	}, nil
 }
 
-func branchToJSON(branchBytes [][]byte) []string {
+func branchToJSON[S [][32]byte](branchBytes S) []string {
 	if branchBytes == nil {
 		return nil
 	}
 	branch := make([]string, len(branchBytes))
 	for i, root := range branchBytes {
-		branch[i] = hexutil.Encode(root)
+		branch[i] = hexutil.Encode(root[:])
 	}
 	return branch
 }
 
-func syncAggregateToJSON(input *v1.SyncAggregate) *SyncAggregate {
-	return &SyncAggregate{
-		SyncCommitteeBits:      hexutil.Encode(input.SyncCommitteeBits),
-		SyncCommitteeSignature: hexutil.Encode(input.SyncCommitteeSignature),
-	}
-}
-
-func lightClientHeaderContainerToJSON(container *v2.LightClientHeaderContainer) (json.RawMessage, error) {
+func lightClientHeaderToJSON(header interfaces.LightClientHeader) (json.RawMessage, error) {
 	// In the case that a finalizedHeader is nil.
-	if container == nil {
+	if header == nil {
 		return nil, nil
 	}
 
-	beacon, err := container.GetBeacon()
-	if err != nil {
-		return nil, errors.Wrap(err, "could not get beacon block header")
-	}
+	var result any
 
-	var header any
-
-	switch t := (container.Header).(type) {
-	case *v2.LightClientHeaderContainer_HeaderAltair:
-		header = &LightClientHeader{Beacon: BeaconBlockHeaderFromConsensus(migration.V1HeaderToV1Alpha1(beacon))}
-	case *v2.LightClientHeaderContainer_HeaderCapella:
-		execution, err := ExecutionPayloadHeaderCapellaFromConsensus(t.HeaderCapella.Execution)
+	switch v := header.Version(); v {
+	case version.Altair:
+		result = &LightClientHeader{Beacon: BeaconBlockHeaderFromConsensus(header.Beacon())}
+	case version.Capella:
+		exInterface, err := header.Execution()
 		if err != nil {
 			return nil, err
 		}
-		header = &LightClientHeaderCapella{
-			Beacon:          BeaconBlockHeaderFromConsensus(migration.V1HeaderToV1Alpha1(beacon)),
-			Execution:       execution,
-			ExecutionBranch: branchToJSON(t.HeaderCapella.ExecutionBranch),
+		ex, ok := exInterface.Proto().(*enginev1.ExecutionPayloadHeaderCapella)
+		if !ok {
+			return nil, fmt.Errorf("execution data is not %T", &enginev1.ExecutionPayloadHeaderCapella{})
 		}
-	case *v2.LightClientHeaderContainer_HeaderDeneb:
-		execution, err := ExecutionPayloadHeaderDenebFromConsensus(t.HeaderDeneb.Execution)
+		execution, err := ExecutionPayloadHeaderCapellaFromConsensus(ex)
 		if err != nil {
 			return nil, err
 		}
-		header = &LightClientHeaderDeneb{
-			Beacon:          BeaconBlockHeaderFromConsensus(migration.V1HeaderToV1Alpha1(beacon)),
+		executionBranch, err := header.ExecutionBranch()
+		if err != nil {
+			return nil, err
+		}
+		result = &LightClientHeaderCapella{
+			Beacon:          BeaconBlockHeaderFromConsensus(header.Beacon()),
 			Execution:       execution,
-			ExecutionBranch: branchToJSON(t.HeaderDeneb.ExecutionBranch),
+			ExecutionBranch: branchToJSON(executionBranch[:]),
+		}
+	case version.Deneb:
+		exInterface, err := header.Execution()
+		if err != nil {
+			return nil, err
+		}
+		ex, ok := exInterface.Proto().(*enginev1.ExecutionPayloadHeaderDeneb)
+		if !ok {
+			return nil, fmt.Errorf("execution data is not %T", &enginev1.ExecutionPayloadHeaderDeneb{})
+		}
+		execution, err := ExecutionPayloadHeaderDenebFromConsensus(ex)
+		if err != nil {
+			return nil, err
+		}
+		executionBranch, err := header.ExecutionBranch()
+		if err != nil {
+			return nil, err
+		}
+		result = &LightClientHeaderDeneb{
+			Beacon:          BeaconBlockHeaderFromConsensus(header.Beacon()),
+			Execution:       execution,
+			ExecutionBranch: branchToJSON(executionBranch[:]),
+		}
+	case version.Electra:
+		exInterface, err := header.Execution()
+		if err != nil {
+			return nil, err
+		}
+		ex, ok := exInterface.Proto().(*enginev1.ExecutionPayloadHeaderElectra)
+		if !ok {
+			return nil, fmt.Errorf("execution data is not %T", &enginev1.ExecutionPayloadHeaderElectra{})
+		}
+		execution, err := ExecutionPayloadHeaderElectraFromConsensus(ex)
+		if err != nil {
+			return nil, err
+		}
+		executionBranch, err := header.ExecutionBranch()
+		if err != nil {
+			return nil, err
+		}
+		result = &LightClientHeaderDeneb{
+			Beacon:          BeaconBlockHeaderFromConsensus(header.Beacon()),
+			Execution:       execution,
+			ExecutionBranch: branchToJSON(executionBranch[:]),
 		}
 	default:
-		return nil, fmt.Errorf("unsupported header type %T", t)
+		return nil, fmt.Errorf("unsupported header version %s", version.String(v))
 	}
 
-	return json.Marshal(header)
+	return json.Marshal(result)
+}
+
+func LightClientBootstrapFromConsensus(bootstrap interfaces.LightClientBootstrap) (*LightClientBootstrap, error) {
+	header, err := lightClientHeaderToJSON(bootstrap.Header())
+	if err != nil {
+		return nil, errors.Wrap(err, "could not marshal light client header")
+	}
+
+	var scBranch [][32]byte
+	if bootstrap.Version() >= version.Electra {
+		b, err := bootstrap.CurrentSyncCommitteeBranchElectra()
+		if err != nil {
+			return nil, err
+		}
+		scBranch = b[:]
+	} else {
+		b, err := bootstrap.CurrentSyncCommitteeBranch()
+		if err != nil {
+			return nil, err
+		}
+		scBranch = b[:]
+	}
+
+	return &LightClientBootstrap{
+		Header:                     header,
+		CurrentSyncCommittee:       SyncCommitteeFromConsensus(bootstrap.CurrentSyncCommittee()),
+		CurrentSyncCommitteeBranch: branchToJSON(scBranch),
+	}, nil
 }

api/server/structs/endpoints_blob.go

@@ -1,7 +1,10 @@
 package structs
 
 type SidecarsResponse struct {
-	Data []*Sidecar `json:"data"`
+	Version             string     `json:"version"`
+	Data                []*Sidecar `json:"data"`
+	ExecutionOptimistic bool       `json:"execution_optimistic"`
+	Finalized           bool       `json:"finalized"`
 }
 
 type Sidecar struct {

beacon-chain/blockchain/BUILD.bazel

@@ -84,7 +84,6 @@ go_library(
         "//monitoring/tracing/trace:go_default_library",
         "//proto/engine/v1:go_default_library",
         "//proto/eth/v1:go_default_library",
-        "//proto/eth/v2:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
         "//proto/prysm/v1alpha1/attestation:go_default_library",
         "//runtime/version:go_default_library",
@@ -141,6 +140,7 @@ go_test(
         "//beacon-chain/core/blocks:go_default_library",
         "//beacon-chain/core/feed/state:go_default_library",
         "//beacon-chain/core/helpers:go_default_library",
+        "//beacon-chain/core/light-client:go_default_library",
         "//beacon-chain/core/signing:go_default_library",
         "//beacon-chain/core/transition:go_default_library",
         "//beacon-chain/das:go_default_library",

beacon-chain/blockchain/chain_info_test.go

@@ -13,7 +13,6 @@ import (
 	fieldparams "github.com/prysmaticlabs/prysm/v5/config/fieldparams"
 	"github.com/prysmaticlabs/prysm/v5/config/params"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
-	consensus_blocks "github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
 	enginev1 "github.com/prysmaticlabs/prysm/v5/proto/engine/v1"
@@ -39,7 +38,7 @@ func prepareForkchoiceState(
 	payloadHash [32]byte,
 	justified *ethpb.Checkpoint,
 	finalized *ethpb.Checkpoint,
-) (state.BeaconState, consensus_blocks.ROBlock, error) {
+) (state.BeaconState, blocks.ROBlock, error) {
 	blockHeader := &ethpb.BeaconBlockHeader{
 		ParentRoot: parentRoot[:],
 	}
@@ -61,7 +60,7 @@ func prepareForkchoiceState(
 	base.BlockRoots[0] = append(base.BlockRoots[0], blockRoot[:]...)
 	st, err := state_native.InitializeFromProtoBellatrix(base)
 	if err != nil {
-		return nil, consensus_blocks.ROBlock{}, err
+		return nil, blocks.ROBlock{}, err
 	}
 	blk := &ethpb.SignedBeaconBlockBellatrix{
 		Block: &ethpb.BeaconBlockBellatrix{
@@ -76,9 +75,9 @@ func prepareForkchoiceState(
 	}
 	signed, err := blocks.NewSignedBeaconBlock(blk)
 	if err != nil {
-		return nil, consensus_blocks.ROBlock{}, err
+		return nil, blocks.ROBlock{}, err
 	}
-	roblock, err := consensus_blocks.NewROBlockWithRoot(signed, blockRoot)
+	roblock, err := blocks.NewROBlockWithRoot(signed, blockRoot)
 	return st, roblock, err
 }
 

beacon-chain/blockchain/kzg/BUILD.bazel

@@ -26,8 +26,7 @@ go_test(
     deps = [
         "//consensus-types/blocks:go_default_library",
         "//testing/require:go_default_library",
-        "@com_github_consensys_gnark_crypto//ecc/bls12-381/fr:go_default_library",
+        "//testing/util:go_default_library",
         "@com_github_crate_crypto_go_kzg_4844//:go_default_library",
-        "@com_github_sirupsen_logrus//:go_default_library",
     ],
 )

beacon-chain/blockchain/kzg/validation_test.go

@@ -1,51 +1,14 @@
 package kzg
 
 import (
-	"bytes"
-	"crypto/sha256"
-	"encoding/binary"
 	"testing"
 
-	"github.com/consensys/gnark-crypto/ecc/bls12-381/fr"
 	GoKZG "github.com/crate-crypto/go-kzg-4844"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v5/testing/require"
-	"github.com/sirupsen/logrus"
+	"github.com/prysmaticlabs/prysm/v5/testing/util"
 )
 
-func deterministicRandomness(seed int64) [32]byte {
-	// Converts an int64 to a byte slice
-	buf := new(bytes.Buffer)
-	err := binary.Write(buf, binary.BigEndian, seed)
-	if err != nil {
-		logrus.WithError(err).Error("Failed to write int64 to bytes buffer")
-		return [32]byte{}
-	}
-	bytes := buf.Bytes()
-
-	return sha256.Sum256(bytes)
-}
-
-// Returns a serialized random field element in big-endian
-func GetRandFieldElement(seed int64) [32]byte {
-	bytes := deterministicRandomness(seed)
-	var r fr.Element
-	r.SetBytes(bytes[:])
-
-	return GoKZG.SerializeScalar(r)
-}
-
-// Returns a random blob using the passed seed as entropy
-func GetRandBlob(seed int64) GoKZG.Blob {
-	var blob GoKZG.Blob
-	bytesPerBlob := GoKZG.ScalarsPerBlob * GoKZG.SerializedScalarSize
-	for i := 0; i < bytesPerBlob; i += GoKZG.SerializedScalarSize {
-		fieldElementBytes := GetRandFieldElement(seed + int64(i))
-		copy(blob[i:i+GoKZG.SerializedScalarSize], fieldElementBytes[:])
-	}
-	return blob
-}
-
 func GenerateCommitmentAndProof(blob GoKZG.Blob) (GoKZG.KZGCommitment, GoKZG.KZGProof, error) {
 	commitment, err := kzgContext.BlobToKZGCommitment(blob, 0)
 	if err != nil {
@@ -74,7 +37,7 @@ func TestBytesToAny(t *testing.T) {
 }
 
 func TestGenerateCommitmentAndProof(t *testing.T) {
-	blob := GetRandBlob(123)
+	blob := util.GetRandBlob(123)
 	commitment, proof, err := GenerateCommitmentAndProof(blob)
 	require.NoError(t, err)
 	expectedCommitment := GoKZG.KZGCommitment{180, 218, 156, 194, 59, 20, 10, 189, 186, 254, 132, 93, 7, 127, 104, 172, 238, 240, 237, 70, 83, 89, 1, 152, 99, 0, 165, 65, 143, 62, 20, 215, 230, 14, 205, 95, 28, 245, 54, 25, 160, 16, 178, 31, 232, 207, 38, 85}

beacon-chain/blockchain/process_block.go

@@ -67,7 +67,10 @@ func (s *Service) postBlockProcess(cfg *postBlockProcessConfig) error {
 	if s.inRegularSync() {
 		defer s.handleSecondFCUCall(cfg, fcuArgs)
 	}
-	defer s.sendLightClientFeeds(cfg)
+	if features.Get().EnableLightClient && slots.ToEpoch(s.CurrentSlot()) >= params.BeaconConfig().AltairForkEpoch {
+		defer s.processLightClientUpdates(cfg)
+		defer s.saveLightClientUpdate(cfg)
+	}
 	defer s.sendStateFeedOnBlock(cfg)
 	defer reportProcessingTime(startTime)
 	defer reportAttestationInclusion(cfg.roblock.Block())
@@ -404,10 +407,9 @@ func (s *Service) savePostStateInfo(ctx context.Context, r [32]byte, b interface
 		return errors.Wrapf(err, "could not save block from slot %d", b.Block().Slot())
 	}
 	if err := s.cfg.StateGen.SaveState(ctx, r, st); err != nil {
-		log.Warnf("Rolling back insertion of block with root %#x", r)
-		if err := s.cfg.BeaconDB.DeleteBlock(ctx, r); err != nil {
-			log.WithError(err).Errorf("Could not delete block with block root %#x", r)
-		}
+		// Do not use parent context in the event it deadlined
+		ctx = trace.NewContext(context.Background(), span)
+		s.rollbackBlock(ctx, r)
 		return errors.Wrap(err, "could not save state")
 	}
 	return nil

beacon-chain/blockchain/process_block_helpers.go

@@ -1,6 +1,7 @@
 package blockchain
 
 import (
+	"bytes"
 	"context"
 	"fmt"
 	"time"
@@ -15,7 +16,6 @@ import (
 	doublylinkedtree "github.com/prysmaticlabs/prysm/v5/beacon-chain/forkchoice/doubly-linked-tree"
 	forkchoicetypes "github.com/prysmaticlabs/prysm/v5/beacon-chain/forkchoice/types"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/state"
-	"github.com/prysmaticlabs/prysm/v5/config/features"
 	field_params "github.com/prysmaticlabs/prysm/v5/config/fieldparams"
 	"github.com/prysmaticlabs/prysm/v5/config/params"
 	consensus_blocks "github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
@@ -24,7 +24,6 @@ import (
 	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
 	mathutil "github.com/prysmaticlabs/prysm/v5/math"
 	"github.com/prysmaticlabs/prysm/v5/monitoring/tracing/trace"
-	ethpbv2 "github.com/prysmaticlabs/prysm/v5/proto/eth/v2"
 	ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v5/time/slots"
 	"github.com/sirupsen/logrus"
@@ -115,64 +114,123 @@ func (s *Service) sendStateFeedOnBlock(cfg *postBlockProcessConfig) {
 	})
 }
 
-// sendLightClientFeeds sends the light client feeds when feature flag is enabled.
-func (s *Service) sendLightClientFeeds(cfg *postBlockProcessConfig) {
-	if features.Get().EnableLightClient {
-		if _, err := s.sendLightClientOptimisticUpdate(cfg.ctx, cfg.roblock, cfg.postState); err != nil {
-			log.WithError(err).Error("Failed to send light client optimistic update")
-		}
-
-		// Get the finalized checkpoint
-		finalized := s.ForkChoicer().FinalizedCheckpoint()
-
-		// LightClientFinalityUpdate needs super majority
-		s.tryPublishLightClientFinalityUpdate(cfg.ctx, cfg.roblock, finalized, cfg.postState)
+func (s *Service) processLightClientUpdates(cfg *postBlockProcessConfig) {
+	if err := s.processLightClientOptimisticUpdate(cfg.ctx, cfg.roblock, cfg.postState); err != nil {
+		log.WithError(err).Error("Failed to process light client optimistic update")
+	}
+	if err := s.processLightClientFinalityUpdate(cfg.ctx, cfg.roblock, cfg.postState); err != nil {
+		log.WithError(err).Error("Failed to process light client finality update")
 	}
 }
 
-func (s *Service) tryPublishLightClientFinalityUpdate(ctx context.Context, signed interfaces.ReadOnlySignedBeaconBlock, finalized *forkchoicetypes.Checkpoint, postState state.BeaconState) {
-	if finalized.Epoch <= s.lastPublishedLightClientEpoch {
-		return
-	}
-
-	config := params.BeaconConfig()
-	if finalized.Epoch < config.AltairForkEpoch {
-		return
-	}
-
-	syncAggregate, err := signed.Block().Body().SyncAggregate()
-	if err != nil || syncAggregate == nil {
-		return
-	}
-
-	// LightClientFinalityUpdate needs super majority
-	if syncAggregate.SyncCommitteeBits.Count()*3 < config.SyncCommitteeSize*2 {
-		return
-	}
-
-	_, err = s.sendLightClientFinalityUpdate(ctx, signed, postState)
+// saveLightClientUpdate saves the light client update for this block
+// if it's better than the already saved one, when feature flag is enabled.
+func (s *Service) saveLightClientUpdate(cfg *postBlockProcessConfig) {
+	attestedRoot := cfg.roblock.Block().ParentRoot()
+	attestedBlock, err := s.getBlock(cfg.ctx, attestedRoot)
 	if err != nil {
-		log.WithError(err).Error("Failed to send light client finality update")
+		log.WithError(err).Error("Saving light client update failed: Could not get attested block")
+		return
+	}
+	if attestedBlock == nil || attestedBlock.IsNil() {
+		log.Error("Saving light client update failed: Attested block is nil")
+		return
+	}
+	attestedState, err := s.cfg.StateGen.StateByRoot(cfg.ctx, attestedRoot)
+	if err != nil {
+		log.WithError(err).Error("Saving light client update failed: Could not get attested state")
+		return
+	}
+	if attestedState == nil || attestedState.IsNil() {
+		log.Error("Saving light client update failed: Attested state is nil")
+		return
+	}
+
+	finalizedRoot := attestedState.FinalizedCheckpoint().Root
+	finalizedBlock, err := s.getBlock(cfg.ctx, [32]byte(finalizedRoot))
+	if err != nil {
+		log.WithError(err).Error("Saving light client update failed: Could not get finalized block")
+		return
+	}
+
+	update, err := lightclient.NewLightClientUpdateFromBeaconState(
+		cfg.ctx,
+		s.CurrentSlot(),
+		cfg.postState,
+		cfg.roblock,
+		attestedState,
+		attestedBlock,
+		finalizedBlock,
+	)
+	if err != nil {
+		log.WithError(err).Error("Saving light client update failed: Could not create light client update")
+		return
+	}
+
+	period := slots.SyncCommitteePeriod(slots.ToEpoch(attestedState.Slot()))
+
+	oldUpdate, err := s.cfg.BeaconDB.LightClientUpdate(cfg.ctx, period)
+	if err != nil {
+		log.WithError(err).Error("Saving light client update failed: Could not get current light client update")
+		return
+	}
+
+	if oldUpdate == nil {
+		if err := s.cfg.BeaconDB.SaveLightClientUpdate(cfg.ctx, period, update); err != nil {
+			log.WithError(err).Error("Saving light client update failed: Could not save light client update")
+		} else {
+			log.WithField("period", period).Debug("Saving light client update: Saved new update")
+		}
+		return
+	}
+
+	isNewUpdateBetter, err := lightclient.IsBetterUpdate(update, oldUpdate)
+	if err != nil {
+		log.WithError(err).Error("Saving light client update failed: Could not compare light client updates")
+		return
+	}
+
+	if isNewUpdateBetter {
+		if err := s.cfg.BeaconDB.SaveLightClientUpdate(cfg.ctx, period, update); err != nil {
+			log.WithError(err).Error("Saving light client update failed: Could not save light client update")
+		} else {
+			log.WithField("period", period).Debug("Saving light client update: Saved new update")
+		}
 	} else {
-		s.lastPublishedLightClientEpoch = finalized.Epoch
+		log.WithField("period", period).Debug("Saving light client update: New update is not better than the current one. Skipping save.")
 	}
 }
 
-// sendLightClientFinalityUpdate sends a light client finality update notification to the state feed.
-func (s *Service) sendLightClientFinalityUpdate(ctx context.Context, signed interfaces.ReadOnlySignedBeaconBlock,
-	postState state.BeaconState) (int, error) {
-	// Get attested state
+// saveLightClientBootstrap saves a light client bootstrap for this block
+// when feature flag is enabled.
+func (s *Service) saveLightClientBootstrap(cfg *postBlockProcessConfig) {
+	blockRoot := cfg.roblock.Root()
+	bootstrap, err := lightclient.NewLightClientBootstrapFromBeaconState(cfg.ctx, s.CurrentSlot(), cfg.postState, cfg.roblock)
+	if err != nil {
+		log.WithError(err).Error("Saving light client bootstrap failed: Could not create light client bootstrap")
+		return
+	}
+	err = s.cfg.BeaconDB.SaveLightClientBootstrap(cfg.ctx, blockRoot[:], bootstrap)
+	if err != nil {
+		log.WithError(err).Error("Saving light client bootstrap failed: Could not save light client bootstrap in DB")
+	}
+}
+
+func (s *Service) processLightClientFinalityUpdate(
+	ctx context.Context,
+	signed interfaces.ReadOnlySignedBeaconBlock,
+	postState state.BeaconState,
+) error {
 	attestedRoot := signed.Block().ParentRoot()
 	attestedBlock, err := s.cfg.BeaconDB.Block(ctx, attestedRoot)
 	if err != nil {
-		return 0, errors.Wrap(err, "could not get attested block")
+		return errors.Wrap(err, "could not get attested block")
 	}
 	attestedState, err := s.cfg.StateGen.StateByRoot(ctx, attestedRoot)
 	if err != nil {
-		return 0, errors.Wrap(err, "could not get attested state")
+		return errors.Wrap(err, "could not get attested state")
 	}
 
-	// Get finalized block
 	var finalizedBlock interfaces.ReadOnlySignedBeaconBlock
 	finalizedCheckPoint := attestedState.FinalizedCheckpoint()
 	if finalizedCheckPoint != nil {
@@ -183,8 +241,14 @@ func (s *Service) sendLightClientFinalityUpdate(ctx context.Context, signed inte
 		}
 	}
 
+	// Check if the finalized checkpoint has changed
+	if finalizedCheckPoint == nil || bytes.Equal(finalizedCheckPoint.GetRoot(), postState.FinalizedCheckpoint().Root) {
+		return nil
+	}
+
 	update, err := lightclient.NewLightClientFinalityUpdateFromBeaconState(
 		ctx,
+		postState.Slot(),
 		postState,
 		signed,
 		attestedState,
@@ -193,38 +257,31 @@ func (s *Service) sendLightClientFinalityUpdate(ctx context.Context, signed inte
 	)
 
 	if err != nil {
-		return 0, errors.Wrap(err, "could not create light client update")
+		return errors.Wrap(err, "could not create light client finality update")
 	}
 
-	// Return the result
-	result := &ethpbv2.LightClientFinalityUpdateWithVersion{
-		Version: ethpbv2.Version(signed.Version()),
-		Data:    update,
-	}
-
-	// Send event
-	return s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
+	s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
 		Type: statefeed.LightClientFinalityUpdate,
-		Data: result,
-	}), nil
+		Data: update,
+	})
+	return nil
 }
 
-// sendLightClientOptimisticUpdate sends a light client optimistic update notification to the state feed.
-func (s *Service) sendLightClientOptimisticUpdate(ctx context.Context, signed interfaces.ReadOnlySignedBeaconBlock,
-	postState state.BeaconState) (int, error) {
-	// Get attested state
+func (s *Service) processLightClientOptimisticUpdate(ctx context.Context, signed interfaces.ReadOnlySignedBeaconBlock,
+	postState state.BeaconState) error {
 	attestedRoot := signed.Block().ParentRoot()
 	attestedBlock, err := s.cfg.BeaconDB.Block(ctx, attestedRoot)
 	if err != nil {
-		return 0, errors.Wrap(err, "could not get attested block")
+		return errors.Wrap(err, "could not get attested block")
 	}
 	attestedState, err := s.cfg.StateGen.StateByRoot(ctx, attestedRoot)
 	if err != nil {
-		return 0, errors.Wrap(err, "could not get attested state")
+		return errors.Wrap(err, "could not get attested state")
 	}
 
 	update, err := lightclient.NewLightClientOptimisticUpdateFromBeaconState(
 		ctx,
+		postState.Slot(),
 		postState,
 		signed,
 		attestedState,
@@ -232,19 +289,15 @@ func (s *Service) sendLightClientOptimisticUpdate(ctx context.Context, signed in
 	)
 
 	if err != nil {
-		return 0, errors.Wrap(err, "could not create light client update")
+		return errors.Wrap(err, "could not create light client optimistic update")
 	}
 
-	// Return the result
-	result := &ethpbv2.LightClientOptimisticUpdateWithVersion{
-		Version: ethpbv2.Version(signed.Version()),
-		Data:    update,
-	}
-
-	return s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
+	s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
 		Type: statefeed.LightClientOptimisticUpdate,
-		Data: result,
-	}), nil
+		Data: update,
+	})
+
+	return nil
 }
 
 // updateCachesPostBlockProcessing updates the next slot cache and handles the epoch

beacon-chain/blockchain/process_block_test.go

@@ -14,6 +14,7 @@ import (
 	"github.com/pkg/errors"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/cache"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/blocks"
+	lightClient "github.com/prysmaticlabs/prysm/v5/beacon-chain/core/light-client"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/signing"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/transition"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/das"
@@ -40,6 +41,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v5/testing/require"
 	"github.com/prysmaticlabs/prysm/v5/testing/util"
 	prysmTime "github.com/prysmaticlabs/prysm/v5/time"
+	"github.com/prysmaticlabs/prysm/v5/time/slots"
 	logTest "github.com/sirupsen/logrus/hooks/test"
 )
 
@@ -2352,6 +2354,62 @@ func TestRollbackBlock(t *testing.T) {
 	require.Equal(t, false, hasState)
 }
 
+func TestRollbackBlock_SavePostStateInfo_ContextDeadline(t *testing.T) {
+	service, tr := minimalTestService(t)
+	ctx := tr.ctx
+
+	st, keys := util.DeterministicGenesisState(t, 64)
+	stateRoot, err := st.HashTreeRoot(ctx)
+	require.NoError(t, err, "Could not hash genesis state")
+
+	require.NoError(t, service.saveGenesisData(ctx, st))
+
+	genesis := blocks.NewGenesisBlock(stateRoot[:])
+	wsb, err := consensusblocks.NewSignedBeaconBlock(genesis)
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wsb), "Could not save genesis block")
+	parentRoot, err := genesis.Block.HashTreeRoot()
+	require.NoError(t, err, "Could not get signing root")
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, st, parentRoot), "Could not save genesis state")
+	require.NoError(t, service.cfg.BeaconDB.SaveHeadBlockRoot(ctx, parentRoot), "Could not save genesis state")
+	require.NoError(t, service.cfg.BeaconDB.SaveJustifiedCheckpoint(ctx, &ethpb.Checkpoint{Root: parentRoot[:]}))
+	require.NoError(t, service.cfg.BeaconDB.SaveFinalizedCheckpoint(ctx, &ethpb.Checkpoint{Root: parentRoot[:]}))
+
+	st, err = service.HeadState(ctx)
+	require.NoError(t, err)
+	b, err := util.GenerateFullBlock(st, keys, util.DefaultBlockGenConfig(), 128)
+	require.NoError(t, err)
+	wsb, err = consensusblocks.NewSignedBeaconBlock(b)
+	require.NoError(t, err)
+	root, err := b.Block.HashTreeRoot()
+	require.NoError(t, err)
+	preState, err := service.getBlockPreState(ctx, wsb.Block())
+	require.NoError(t, err)
+	postState, err := service.validateStateTransition(ctx, preState, wsb)
+	require.NoError(t, err)
+
+	// Save state summaries so that the cache is flushed and saved to disk
+	// later.
+	for i := 1; i <= 127; i++ {
+		require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(ctx, &ethpb.StateSummary{
+			Slot: primitives.Slot(i),
+			Root: bytesutil.Bytes32(uint64(i)),
+		}))
+	}
+
+	// Set deadlined context when saving block and state
+	cancCtx, canc := context.WithCancel(ctx)
+	canc()
+
+	require.ErrorContains(t, context.Canceled.Error(), service.savePostStateInfo(cancCtx, root, wsb, postState))
+
+	// The block should no longer exist.
+	require.Equal(t, false, service.cfg.BeaconDB.HasBlock(ctx, root))
+	hasState, err := service.cfg.StateGen.HasState(ctx, root)
+	require.NoError(t, err)
+	require.Equal(t, false, hasState)
+}
+
 func TestRollbackBlock_ContextDeadline(t *testing.T) {
 	service, tr := minimalTestService(t)
 	ctx := tr.ctx
@@ -2446,3 +2504,605 @@ func fakeResult(missing []uint64) map[uint64]struct{} {
 	}
 	return r
 }
+
+func TestSaveLightClientUpdate(t *testing.T) {
+	featCfg := &features.Flags{}
+	featCfg.EnableLightClient = true
+	reset := features.InitWithReset(featCfg)
+
+	s, tr := minimalTestService(t)
+	ctx := tr.ctx
+
+	t.Run("Altair", func(t *testing.T) {
+		t.Run("No old update", func(t *testing.T) {
+			l := util.NewTestLightClient(t).SetupTestAltair()
+
+			s.genesisTime = time.Unix(time.Now().Unix()-(int64(params.BeaconConfig().AltairForkEpoch)*int64(params.BeaconConfig().SlotsPerEpoch)*int64(params.BeaconConfig().SecondsPerSlot)), 0)
+
+			err := s.cfg.BeaconDB.SaveBlock(ctx, l.AttestedBlock)
+			require.NoError(t, err)
+			attestedBlockRoot, err := l.AttestedBlock.Block().HashTreeRoot()
+			require.NoError(t, err)
+			err = s.cfg.BeaconDB.SaveState(ctx, l.AttestedState, attestedBlockRoot)
+			require.NoError(t, err)
+
+			currentBlockRoot, err := l.Block.Block().HashTreeRoot()
+			require.NoError(t, err)
+			roblock, err := consensusblocks.NewROBlockWithRoot(l.Block, currentBlockRoot)
+			require.NoError(t, err)
+
+			err = s.cfg.BeaconDB.SaveBlock(ctx, roblock)
+			require.NoError(t, err)
+			err = s.cfg.BeaconDB.SaveState(ctx, l.State, currentBlockRoot)
+			require.NoError(t, err)
+
+			err = s.cfg.BeaconDB.SaveBlock(ctx, l.FinalizedBlock)
+			require.NoError(t, err)
+
+			cfg := &postBlockProcessConfig{
+				ctx:            ctx,
+				roblock:        roblock,
+				postState:      l.State,
+				isValidPayload: true,
+			}
+
+			s.saveLightClientUpdate(cfg)
+
+			// Check that the light client update is saved
+			period := slots.SyncCommitteePeriod(slots.ToEpoch(l.AttestedState.Slot()))
+
+			u, err := s.cfg.BeaconDB.LightClientUpdate(ctx, period)
+			require.NoError(t, err)
+			require.NotNil(t, u)
+			attestedStateRoot, err := l.AttestedState.HashTreeRoot(ctx)
+			require.NoError(t, err)
+			require.Equal(t, attestedStateRoot, [32]byte(u.AttestedHeader().Beacon().StateRoot))
+			require.Equal(t, u.Version(), version.Altair)
+		})
+
+		t.Run("New update is better", func(t *testing.T) {
+			l := util.NewTestLightClient(t).SetupTestAltair()
+
+			s.genesisTime = time.Unix(time.Now().Unix()-(int64(params.BeaconConfig().AltairForkEpoch)*int64(params.BeaconConfig().SlotsPerEpoch)*int64(params.BeaconConfig().SecondsPerSlot)), 0)
+
+			err := s.cfg.BeaconDB.SaveBlock(ctx, l.AttestedBlock)
+			require.NoError(t, err)
+			attestedBlockRoot, err := l.AttestedBlock.Block().HashTreeRoot()
+			require.NoError(t, err)
+			err = s.cfg.BeaconDB.SaveState(ctx, l.AttestedState, attestedBlockRoot)
+			require.NoError(t, err)
+
+			currentBlockRoot, err := l.Block.Block().HashTreeRoot()
+			require.NoError(t, err)
+			roblock, err := consensusblocks.NewROBlockWithRoot(l.Block, currentBlockRoot)
+			require.NoError(t, err)
+
+			err = s.cfg.BeaconDB.SaveBlock(ctx, roblock)
+			require.NoError(t, err)
+			err = s.cfg.BeaconDB.SaveState(ctx, l.State, currentBlockRoot)
+			require.NoError(t, err)
+
+			err = s.cfg.BeaconDB.SaveBlock(ctx, l.FinalizedBlock)
+			require.NoError(t, err)
+
+			cfg := &postBlockProcessConfig{
+				ctx:            ctx,
+				roblock:        roblock,
+				postState:      l.State,
+				isValidPayload: true,
+			}
+
+			period := slots.SyncCommitteePeriod(slots.ToEpoch(l.AttestedState.Slot()))
+
+			// create and save old update
+			oldUpdate, err := lightClient.CreateDefaultLightClientUpdate(s.CurrentSlot(), l.AttestedState)
+			require.NoError(t, err)
+
+			err = s.cfg.BeaconDB.SaveLightClientUpdate(ctx, period, oldUpdate)
+			require.NoError(t, err)
+
+			s.saveLightClientUpdate(cfg)
+
+			u, err := s.cfg.BeaconDB.LightClientUpdate(ctx, period)
+			require.NoError(t, err)
+			require.NotNil(t, u)
+			attestedStateRoot, err := l.AttestedState.HashTreeRoot(ctx)
+			require.NoError(t, err)
+			require.Equal(t, attestedStateRoot, [32]byte(u.AttestedHeader().Beacon().StateRoot))
+			require.Equal(t, u.Version(), version.Altair)
+		})
+
+		t.Run("Old update is better", func(t *testing.T) {
+			l := util.NewTestLightClient(t).SetupTestAltair()
+
+			s.genesisTime = time.Unix(time.Now().Unix()-(int64(params.BeaconConfig().AltairForkEpoch)*int64(params.BeaconConfig().SlotsPerEpoch)*int64(params.BeaconConfig().SecondsPerSlot)), 0)
+
+			err := s.cfg.BeaconDB.SaveBlock(ctx, l.AttestedBlock)
+			require.NoError(t, err)
+			attestedBlockRoot, err := l.AttestedBlock.Block().HashTreeRoot()
+			require.NoError(t, err)
+			err = s.cfg.BeaconDB.SaveState(ctx, l.AttestedState, attestedBlockRoot)
+			require.NoError(t, err)
+
+			currentBlockRoot, err := l.Block.Block().HashTreeRoot()
+			require.NoError(t, err)
+			roblock, err := consensusblocks.NewROBlockWithRoot(l.Block, currentBlockRoot)
+			require.NoError(t, err)
+
+			err = s.cfg.BeaconDB.SaveBlock(ctx, roblock)
+			require.NoError(t, err)
+			err = s.cfg.BeaconDB.SaveState(ctx, l.State, currentBlockRoot)
+			require.NoError(t, err)
+
+			err = s.cfg.BeaconDB.SaveBlock(ctx, l.FinalizedBlock)
+			require.NoError(t, err)
+
+			cfg := &postBlockProcessConfig{
+				ctx:            ctx,
+				roblock:        roblock,
+				postState:      l.State,
+				isValidPayload: true,
+			}
+
+			period := slots.SyncCommitteePeriod(slots.ToEpoch(l.AttestedState.Slot()))
+
+			// create and save old update
+			oldUpdate, err := lightClient.CreateDefaultLightClientUpdate(s.CurrentSlot(), l.AttestedState)
+			require.NoError(t, err)
+
+			scb := make([]byte, 64)
+			for i := 0; i < 5; i++ {
+				scb[i] = 0x01
+			}
+			oldUpdate.SetSyncAggregate(&ethpb.SyncAggregate{
+				SyncCommitteeBits:      scb,
+				SyncCommitteeSignature: make([]byte, 96),
+			})
+
+			err = s.cfg.BeaconDB.SaveLightClientUpdate(ctx, period, oldUpdate)
+			require.NoError(t, err)
+
+			s.saveLightClientUpdate(cfg)
+
+			u, err := s.cfg.BeaconDB.LightClientUpdate(ctx, period)
+			require.NoError(t, err)
+			require.NotNil(t, u)
+			require.DeepEqual(t, oldUpdate, u)
+			require.Equal(t, u.Version(), version.Altair)
+		})
+	})
+
+	t.Run("Capella", func(t *testing.T) {
+		t.Run("No old update", func(t *testing.T) {
+			l := util.NewTestLightClient(t).SetupTestCapella(false)
+
+			s.genesisTime = time.Unix(time.Now().Unix()-(int64(params.BeaconConfig().CapellaForkEpoch)*int64(params.BeaconConfig().SlotsPerEpoch)*int64(params.BeaconConfig().SecondsPerSlot)), 0)
+
+			err := s.cfg.BeaconDB.SaveBlock(ctx, l.AttestedBlock)
+			require.NoError(t, err)
+			attestedBlockRoot, err := l.AttestedBlock.Block().HashTreeRoot()
+			require.NoError(t, err)
+			err = s.cfg.BeaconDB.SaveState(ctx, l.AttestedState, attestedBlockRoot)
+			require.NoError(t, err)
+
+			currentBlockRoot, err := l.Block.Block().HashTreeRoot()
+			require.NoError(t, err)
+			roblock, err := consensusblocks.NewROBlockWithRoot(l.Block, currentBlockRoot)
+			require.NoError(t, err)
+
+			err = s.cfg.BeaconDB.SaveBlock(ctx, roblock)
+			require.NoError(t, err)
+			err = s.cfg.BeaconDB.SaveState(ctx, l.State, currentBlockRoot)
+			require.NoError(t, err)
+
+			err = s.cfg.BeaconDB.SaveBlock(ctx, l.FinalizedBlock)
+			require.NoError(t, err)
+
+			cfg := &postBlockProcessConfig{
+				ctx:            ctx,
+				roblock:        roblock,
+				postState:      l.State,
+				isValidPayload: true,
+			}
+
+			s.saveLightClientUpdate(cfg)
+
+			// Check that the light client update is saved
+			period := slots.SyncCommitteePeriod(slots.ToEpoch(l.AttestedState.Slot()))
+			u, err := s.cfg.BeaconDB.LightClientUpdate(ctx, period)
+			require.NoError(t, err)
+			require.NotNil(t, u)
+			attestedStateRoot, err := l.AttestedState.HashTreeRoot(ctx)
+			require.NoError(t, err)
+			require.Equal(t, attestedStateRoot, [32]byte(u.AttestedHeader().Beacon().StateRoot))
+			require.Equal(t, u.Version(), version.Capella)
+		})
+
+		t.Run("New update is better", func(t *testing.T) {
+			l := util.NewTestLightClient(t).SetupTestCapella(false)
+
+			s.genesisTime = time.Unix(time.Now().Unix()-(int64(params.BeaconConfig().CapellaForkEpoch)*int64(params.BeaconConfig().SlotsPerEpoch)*int64(params.BeaconConfig().SecondsPerSlot)), 0)
+
+			err := s.cfg.BeaconDB.SaveBlock(ctx, l.AttestedBlock)
+			require.NoError(t, err)
+			attestedBlockRoot, err := l.AttestedBlock.Block().HashTreeRoot()
+			require.NoError(t, err)
+			err = s.cfg.BeaconDB.SaveState(ctx, l.AttestedState, attestedBlockRoot)
+			require.NoError(t, err)
+
+			currentBlockRoot, err := l.Block.Block().HashTreeRoot()
+			require.NoError(t, err)
+			roblock, err := consensusblocks.NewROBlockWithRoot(l.Block, currentBlockRoot)
+			require.NoError(t, err)
+
+			err = s.cfg.BeaconDB.SaveBlock(ctx, roblock)
+			require.NoError(t, err)
+			err = s.cfg.BeaconDB.SaveState(ctx, l.State, currentBlockRoot)
+			require.NoError(t, err)
+
+			err = s.cfg.BeaconDB.SaveBlock(ctx, l.FinalizedBlock)
+			require.NoError(t, err)
+
+			cfg := &postBlockProcessConfig{
+				ctx:            ctx,
+				roblock:        roblock,
+				postState:      l.State,
+				isValidPayload: true,
+			}
+
+			period := slots.SyncCommitteePeriod(slots.ToEpoch(l.AttestedState.Slot()))
+
+			// create and save old update
+			oldUpdate, err := lightClient.CreateDefaultLightClientUpdate(s.CurrentSlot(), l.AttestedState)
+			require.NoError(t, err)
+
+			err = s.cfg.BeaconDB.SaveLightClientUpdate(ctx, period, oldUpdate)
+			require.NoError(t, err)
+
+			s.saveLightClientUpdate(cfg)
+
+			u, err := s.cfg.BeaconDB.LightClientUpdate(ctx, period)
+			require.NoError(t, err)
+			require.NotNil(t, u)
+			attestedStateRoot, err := l.AttestedState.HashTreeRoot(ctx)
+			require.NoError(t, err)
+			require.Equal(t, attestedStateRoot, [32]byte(u.AttestedHeader().Beacon().StateRoot))
+			require.Equal(t, u.Version(), version.Capella)
+		})
+
+		t.Run("Old update is better", func(t *testing.T) {
+			l := util.NewTestLightClient(t).SetupTestCapella(false)
+
+			s.genesisTime = time.Unix(time.Now().Unix()-(int64(params.BeaconConfig().CapellaForkEpoch)*int64(params.BeaconConfig().SlotsPerEpoch)*int64(params.BeaconConfig().SecondsPerSlot)), 0)
+
+			err := s.cfg.BeaconDB.SaveBlock(ctx, l.AttestedBlock)
+			require.NoError(t, err)
+			attestedBlockRoot, err := l.AttestedBlock.Block().HashTreeRoot()
+			require.NoError(t, err)
+			err = s.cfg.BeaconDB.SaveState(ctx, l.AttestedState, attestedBlockRoot)
+			require.NoError(t, err)
+
+			currentBlockRoot, err := l.Block.Block().HashTreeRoot()
+			require.NoError(t, err)
+			roblock, err := consensusblocks.NewROBlockWithRoot(l.Block, currentBlockRoot)
+			require.NoError(t, err)
+
+			err = s.cfg.BeaconDB.SaveBlock(ctx, roblock)
+			require.NoError(t, err)
+			err = s.cfg.BeaconDB.SaveState(ctx, l.State, currentBlockRoot)
+			require.NoError(t, err)
+
+			err = s.cfg.BeaconDB.SaveBlock(ctx, l.FinalizedBlock)
+			require.NoError(t, err)
+
+			cfg := &postBlockProcessConfig{
+				ctx:            ctx,
+				roblock:        roblock,
+				postState:      l.State,
+				isValidPayload: true,
+			}
+
+			period := slots.SyncCommitteePeriod(slots.ToEpoch(l.AttestedState.Slot()))
+
+			// create and save old update
+			oldUpdate, err := lightClient.CreateDefaultLightClientUpdate(s.CurrentSlot(), l.AttestedState)
+			require.NoError(t, err)
+
+			scb := make([]byte, 64)
+			for i := 0; i < 5; i++ {
+				scb[i] = 0x01
+			}
+			oldUpdate.SetSyncAggregate(&ethpb.SyncAggregate{
+				SyncCommitteeBits:      scb,
+				SyncCommitteeSignature: make([]byte, 96),
+			})
+
+			err = s.cfg.BeaconDB.SaveLightClientUpdate(ctx, period, oldUpdate)
+			require.NoError(t, err)
+
+			s.saveLightClientUpdate(cfg)
+
+			u, err := s.cfg.BeaconDB.LightClientUpdate(ctx, period)
+			require.NoError(t, err)
+			require.NotNil(t, u)
+			require.DeepEqual(t, oldUpdate, u)
+			require.Equal(t, u.Version(), version.Capella)
+		})
+	})
+
+	t.Run("Deneb", func(t *testing.T) {
+		t.Run("No old update", func(t *testing.T) {
+			l := util.NewTestLightClient(t).SetupTestDeneb(false)
+
+			s.genesisTime = time.Unix(time.Now().Unix()-(int64(params.BeaconConfig().DenebForkEpoch)*int64(params.BeaconConfig().SlotsPerEpoch)*int64(params.BeaconConfig().SecondsPerSlot)), 0)
+
+			err := s.cfg.BeaconDB.SaveBlock(ctx, l.AttestedBlock)
+			require.NoError(t, err)
+			attestedBlockRoot, err := l.AttestedBlock.Block().HashTreeRoot()
+			require.NoError(t, err)
+			err = s.cfg.BeaconDB.SaveState(ctx, l.AttestedState, attestedBlockRoot)
+			require.NoError(t, err)
+
+			currentBlockRoot, err := l.Block.Block().HashTreeRoot()
+			require.NoError(t, err)
+			roblock, err := consensusblocks.NewROBlockWithRoot(l.Block, currentBlockRoot)
+			require.NoError(t, err)
+
+			err = s.cfg.BeaconDB.SaveBlock(ctx, roblock)
+			require.NoError(t, err)
+			err = s.cfg.BeaconDB.SaveState(ctx, l.State, currentBlockRoot)
+			require.NoError(t, err)
+
+			err = s.cfg.BeaconDB.SaveBlock(ctx, l.FinalizedBlock)
+			require.NoError(t, err)
+
+			cfg := &postBlockProcessConfig{
+				ctx:            ctx,
+				roblock:        roblock,
+				postState:      l.State,
+				isValidPayload: true,
+			}
+
+			s.saveLightClientUpdate(cfg)
+
+			// Check that the light client update is saved
+			period := slots.SyncCommitteePeriod(slots.ToEpoch(l.AttestedState.Slot()))
+			u, err := s.cfg.BeaconDB.LightClientUpdate(ctx, period)
+			require.NoError(t, err)
+			require.NotNil(t, u)
+			attestedStateRoot, err := l.AttestedState.HashTreeRoot(ctx)
+			require.NoError(t, err)
+			require.Equal(t, attestedStateRoot, [32]byte(u.AttestedHeader().Beacon().StateRoot))
+			require.Equal(t, u.Version(), version.Deneb)
+		})
+
+		t.Run("New update is better", func(t *testing.T) {
+			l := util.NewTestLightClient(t).SetupTestDeneb(false)
+
+			s.genesisTime = time.Unix(time.Now().Unix()-(int64(params.BeaconConfig().DenebForkEpoch)*int64(params.BeaconConfig().SlotsPerEpoch)*int64(params.BeaconConfig().SecondsPerSlot)), 0)
+
+			err := s.cfg.BeaconDB.SaveBlock(ctx, l.AttestedBlock)
+			require.NoError(t, err)
+			attestedBlockRoot, err := l.AttestedBlock.Block().HashTreeRoot()
+			require.NoError(t, err)
+			err = s.cfg.BeaconDB.SaveState(ctx, l.AttestedState, attestedBlockRoot)
+			require.NoError(t, err)
+
+			currentBlockRoot, err := l.Block.Block().HashTreeRoot()
+			require.NoError(t, err)
+			roblock, err := consensusblocks.NewROBlockWithRoot(l.Block, currentBlockRoot)
+			require.NoError(t, err)
+
+			err = s.cfg.BeaconDB.SaveBlock(ctx, roblock)
+			require.NoError(t, err)
+			err = s.cfg.BeaconDB.SaveState(ctx, l.State, currentBlockRoot)
+			require.NoError(t, err)
+
+			err = s.cfg.BeaconDB.SaveBlock(ctx, l.FinalizedBlock)
+			require.NoError(t, err)
+
+			cfg := &postBlockProcessConfig{
+				ctx:            ctx,
+				roblock:        roblock,
+				postState:      l.State,
+				isValidPayload: true,
+			}
+
+			period := slots.SyncCommitteePeriod(slots.ToEpoch(l.AttestedState.Slot()))
+
+			// create and save old update
+			oldUpdate, err := lightClient.CreateDefaultLightClientUpdate(s.CurrentSlot(), l.AttestedState)
+			require.NoError(t, err)
+
+			err = s.cfg.BeaconDB.SaveLightClientUpdate(ctx, period, oldUpdate)
+			require.NoError(t, err)
+
+			s.saveLightClientUpdate(cfg)
+
+			u, err := s.cfg.BeaconDB.LightClientUpdate(ctx, period)
+			require.NoError(t, err)
+			require.NotNil(t, u)
+			attestedStateRoot, err := l.AttestedState.HashTreeRoot(ctx)
+			require.NoError(t, err)
+			require.Equal(t, attestedStateRoot, [32]byte(u.AttestedHeader().Beacon().StateRoot))
+			require.Equal(t, u.Version(), version.Deneb)
+		})
+
+		t.Run("Old update is better", func(t *testing.T) {
+			l := util.NewTestLightClient(t).SetupTestDeneb(false)
+
+			s.genesisTime = time.Unix(time.Now().Unix()-(int64(params.BeaconConfig().DenebForkEpoch)*int64(params.BeaconConfig().SlotsPerEpoch)*int64(params.BeaconConfig().SecondsPerSlot)), 0)
+
+			err := s.cfg.BeaconDB.SaveBlock(ctx, l.AttestedBlock)
+			require.NoError(t, err)
+			attestedBlockRoot, err := l.AttestedBlock.Block().HashTreeRoot()
+			require.NoError(t, err)
+			err = s.cfg.BeaconDB.SaveState(ctx, l.AttestedState, attestedBlockRoot)
+			require.NoError(t, err)
+
+			currentBlockRoot, err := l.Block.Block().HashTreeRoot()
+			require.NoError(t, err)
+			roblock, err := consensusblocks.NewROBlockWithRoot(l.Block, currentBlockRoot)
+			require.NoError(t, err)
+
+			err = s.cfg.BeaconDB.SaveBlock(ctx, roblock)
+			require.NoError(t, err)
+			err = s.cfg.BeaconDB.SaveState(ctx, l.State, currentBlockRoot)
+			require.NoError(t, err)
+
+			err = s.cfg.BeaconDB.SaveBlock(ctx, l.FinalizedBlock)
+			require.NoError(t, err)
+
+			cfg := &postBlockProcessConfig{
+				ctx:            ctx,
+				roblock:        roblock,
+				postState:      l.State,
+				isValidPayload: true,
+			}
+
+			period := slots.SyncCommitteePeriod(slots.ToEpoch(l.AttestedState.Slot()))
+
+			// create and save old update
+			oldUpdate, err := lightClient.CreateDefaultLightClientUpdate(s.CurrentSlot(), l.AttestedState)
+			require.NoError(t, err)
+
+			scb := make([]byte, 64)
+			for i := 0; i < 5; i++ {
+				scb[i] = 0x01
+			}
+			oldUpdate.SetSyncAggregate(&ethpb.SyncAggregate{
+				SyncCommitteeBits:      scb,
+				SyncCommitteeSignature: make([]byte, 96),
+			})
+
+			err = s.cfg.BeaconDB.SaveLightClientUpdate(ctx, period, oldUpdate)
+			require.NoError(t, err)
+
+			s.saveLightClientUpdate(cfg)
+
+			u, err := s.cfg.BeaconDB.LightClientUpdate(ctx, period)
+			require.NoError(t, err)
+			require.NotNil(t, u)
+			require.DeepEqual(t, oldUpdate, u)
+			require.Equal(t, u.Version(), version.Deneb)
+		})
+	})
+
+	reset()
+}
+
+func TestSaveLightClientBootstrap(t *testing.T) {
+	featCfg := &features.Flags{}
+	featCfg.EnableLightClient = true
+	reset := features.InitWithReset(featCfg)
+
+	s, tr := minimalTestService(t)
+	ctx := tr.ctx
+
+	t.Run("Altair", func(t *testing.T) {
+		l := util.NewTestLightClient(t).SetupTestAltair()
+
+		s.genesisTime = time.Unix(time.Now().Unix()-(int64(params.BeaconConfig().AltairForkEpoch)*int64(params.BeaconConfig().SlotsPerEpoch)*int64(params.BeaconConfig().SecondsPerSlot)), 0)
+
+		currentBlockRoot, err := l.Block.Block().HashTreeRoot()
+		require.NoError(t, err)
+		roblock, err := consensusblocks.NewROBlockWithRoot(l.Block, currentBlockRoot)
+		require.NoError(t, err)
+
+		err = s.cfg.BeaconDB.SaveBlock(ctx, roblock)
+		require.NoError(t, err)
+		err = s.cfg.BeaconDB.SaveState(ctx, l.State, currentBlockRoot)
+		require.NoError(t, err)
+
+		cfg := &postBlockProcessConfig{
+			ctx:            ctx,
+			roblock:        roblock,
+			postState:      l.State,
+			isValidPayload: true,
+		}
+
+		s.saveLightClientBootstrap(cfg)
+
+		// Check that the light client bootstrap is saved
+		b, err := s.cfg.BeaconDB.LightClientBootstrap(ctx, currentBlockRoot[:])
+		require.NoError(t, err)
+		require.NotNil(t, b)
+
+		stateRoot, err := l.State.HashTreeRoot(ctx)
+		require.NoError(t, err)
+		require.Equal(t, stateRoot, [32]byte(b.Header().Beacon().StateRoot))
+		require.Equal(t, b.Version(), version.Altair)
+	})
+
+	t.Run("Capella", func(t *testing.T) {
+		l := util.NewTestLightClient(t).SetupTestCapella(false)
+
+		s.genesisTime = time.Unix(time.Now().Unix()-(int64(params.BeaconConfig().CapellaForkEpoch)*int64(params.BeaconConfig().SlotsPerEpoch)*int64(params.BeaconConfig().SecondsPerSlot)), 0)
+
+		currentBlockRoot, err := l.Block.Block().HashTreeRoot()
+		require.NoError(t, err)
+		roblock, err := consensusblocks.NewROBlockWithRoot(l.Block, currentBlockRoot)
+		require.NoError(t, err)
+
+		err = s.cfg.BeaconDB.SaveBlock(ctx, roblock)
+		require.NoError(t, err)
+		err = s.cfg.BeaconDB.SaveState(ctx, l.State, currentBlockRoot)
+		require.NoError(t, err)
+
+		cfg := &postBlockProcessConfig{
+			ctx:            ctx,
+			roblock:        roblock,
+			postState:      l.State,
+			isValidPayload: true,
+		}
+
+		s.saveLightClientBootstrap(cfg)
+
+		// Check that the light client bootstrap is saved
+		b, err := s.cfg.BeaconDB.LightClientBootstrap(ctx, currentBlockRoot[:])
+		require.NoError(t, err)
+		require.NotNil(t, b)
+
+		stateRoot, err := l.State.HashTreeRoot(ctx)
+		require.NoError(t, err)
+		require.Equal(t, stateRoot, [32]byte(b.Header().Beacon().StateRoot))
+		require.Equal(t, b.Version(), version.Capella)
+	})
+
+	t.Run("Deneb", func(t *testing.T) {
+		l := util.NewTestLightClient(t).SetupTestDeneb(false)
+
+		s.genesisTime = time.Unix(time.Now().Unix()-(int64(params.BeaconConfig().DenebForkEpoch)*int64(params.BeaconConfig().SlotsPerEpoch)*int64(params.BeaconConfig().SecondsPerSlot)), 0)
+
+		currentBlockRoot, err := l.Block.Block().HashTreeRoot()
+		require.NoError(t, err)
+		roblock, err := consensusblocks.NewROBlockWithRoot(l.Block, currentBlockRoot)
+		require.NoError(t, err)
+
+		err = s.cfg.BeaconDB.SaveBlock(ctx, roblock)
+		require.NoError(t, err)
+		err = s.cfg.BeaconDB.SaveState(ctx, l.State, currentBlockRoot)
+		require.NoError(t, err)
+
+		cfg := &postBlockProcessConfig{
+			ctx:            ctx,
+			roblock:        roblock,
+			postState:      l.State,
+			isValidPayload: true,
+		}
+
+		s.saveLightClientBootstrap(cfg)
+
+		// Check that the light client bootstrap is saved
+		b, err := s.cfg.BeaconDB.LightClientBootstrap(ctx, currentBlockRoot[:])
+		require.NoError(t, err)
+		require.NotNil(t, b)
+
+		stateRoot, err := l.State.HashTreeRoot(ctx)
+		require.NoError(t, err)
+		require.Equal(t, stateRoot, [32]byte(b.Header().Beacon().StateRoot))
+		require.Equal(t, b.Version(), version.Deneb)
+	})
+
+	reset()
+}

beacon-chain/blockchain/receive_attestation_test.go

@@ -10,7 +10,6 @@ import (
 	forkchoicetypes "github.com/prysmaticlabs/prysm/v5/beacon-chain/forkchoice/types"
 	"github.com/prysmaticlabs/prysm/v5/config/params"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
-	consensus_blocks "github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
 	ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
@@ -87,9 +86,7 @@ func TestProcessAttestations_Ok(t *testing.T) {
 	require.NoError(t, err)
 	require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, state, blkRoot))
 	attsToSave := make([]ethpb.Att, len(atts))
-	for i, a := range atts {
-		attsToSave[i] = a
-	}
+	copy(attsToSave, atts)
 	require.NoError(t, service.cfg.AttPool.SaveForkchoiceAttestations(attsToSave))
 	service.processAttestations(ctx, 0)
 	require.Equal(t, 0, len(service.cfg.AttPool.ForkchoiceAttestations()))
@@ -119,7 +116,7 @@ func TestService_ProcessAttestationsAndUpdateHead(t *testing.T) {
 	postState, err := service.validateStateTransition(ctx, preState, wsb)
 	require.NoError(t, err)
 	require.NoError(t, service.savePostStateInfo(ctx, tRoot, wsb, postState))
-	roblock, err := consensus_blocks.NewROBlockWithRoot(wsb, tRoot)
+	roblock, err := blocks.NewROBlockWithRoot(wsb, tRoot)
 	require.NoError(t, err)
 	require.NoError(t, service.postBlockProcess(&postBlockProcessConfig{ctx, roblock, [32]byte{}, postState, false}))
 	copied, err = service.cfg.StateGen.StateByRoot(ctx, tRoot)
@@ -131,9 +128,7 @@ func TestService_ProcessAttestationsAndUpdateHead(t *testing.T) {
 	atts, err := util.GenerateAttestations(copied, pks, 1, 1, false)
 	require.NoError(t, err)
 	attsToSave := make([]ethpb.Att, len(atts))
-	for i, a := range atts {
-		attsToSave[i] = a
-	}
+	copy(attsToSave, atts)
 	require.NoError(t, service.cfg.AttPool.SaveForkchoiceAttestations(attsToSave))
 	// Verify the target is in forkchoice
 	require.Equal(t, true, fcs.HasNode(bytesutil.ToBytes32(atts[0].GetData().BeaconBlockRoot)))
@@ -181,7 +176,7 @@ func TestService_UpdateHead_NoAtts(t *testing.T) {
 	postState, err := service.validateStateTransition(ctx, preState, wsb)
 	require.NoError(t, err)
 	require.NoError(t, service.savePostStateInfo(ctx, tRoot, wsb, postState))
-	roblock, err := consensus_blocks.NewROBlockWithRoot(wsb, tRoot)
+	roblock, err := blocks.NewROBlockWithRoot(wsb, tRoot)
 	require.NoError(t, err)
 	require.NoError(t, service.postBlockProcess(&postBlockProcessConfig{ctx, roblock, [32]byte{}, postState, false}))
 	require.Equal(t, 2, fcs.NodeCount())

beacon-chain/blockchain/receive_block.go

@@ -17,8 +17,6 @@ import (
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/v5/config/features"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
-	consensus_blocks "github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
-	consensusblocks "github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/interfaces"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
@@ -85,7 +83,7 @@ func (s *Service) ReceiveBlock(ctx context.Context, block interfaces.ReadOnlySig
 	}
 
 	currentCheckpoints := s.saveCurrentCheckpoints(preState)
-	roblock, err := consensus_blocks.NewROBlockWithRoot(blockCopy, blockRoot)
+	roblock, err := blocks.NewROBlockWithRoot(blockCopy, blockRoot)
 	if err != nil {
 		return err
 	}
@@ -190,7 +188,7 @@ func (s *Service) updateCheckpoints(
 func (s *Service) validateExecutionAndConsensus(
 	ctx context.Context,
 	preState state.BeaconState,
-	block consensusblocks.ROBlock,
+	block blocks.ROBlock,
 ) (state.BeaconState, bool, error) {
 	preStateVersion, preStateHeader, err := getStateVersionAndPayload(preState)
 	if err != nil {
@@ -560,7 +558,7 @@ func (s *Service) sendBlockAttestationsToSlasher(signed interfaces.ReadOnlySigne
 }
 
 // validateExecutionOnBlock notifies the engine of the incoming block execution payload and returns true if the payload is valid
-func (s *Service) validateExecutionOnBlock(ctx context.Context, ver int, header interfaces.ExecutionData, block consensusblocks.ROBlock) (bool, error) {
+func (s *Service) validateExecutionOnBlock(ctx context.Context, ver int, header interfaces.ExecutionData, block blocks.ROBlock) (bool, error) {
 	isValidPayload, err := s.notifyNewPayload(ctx, ver, header, block)
 	if err != nil {
 		s.cfg.ForkChoiceStore.Lock()

beacon-chain/blockchain/service.go

@@ -36,9 +36,7 @@ import (
 	fieldparams "github.com/prysmaticlabs/prysm/v5/config/fieldparams"
 	"github.com/prysmaticlabs/prysm/v5/config/params"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
-	consensus_blocks "github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/interfaces"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
 	"github.com/prysmaticlabs/prysm/v5/monitoring/tracing/trace"
 	ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
@@ -49,25 +47,24 @@ import (
 // Service represents a service that handles the internal
 // logic of managing the full PoS beacon chain.
 type Service struct {
-	cfg                           *config
-	ctx                           context.Context
-	cancel                        context.CancelFunc
-	genesisTime                   time.Time
-	head                          *head
-	headLock                      sync.RWMutex
-	originBlockRoot               [32]byte // genesis root, or weak subjectivity checkpoint root, depending on how the node is initialized
-	boundaryRoots                 [][32]byte
-	checkpointStateCache          *cache.CheckpointStateCache
-	initSyncBlocks                map[[32]byte]interfaces.ReadOnlySignedBeaconBlock
-	initSyncBlocksLock            sync.RWMutex
-	wsVerifier                    *WeakSubjectivityVerifier
-	clockSetter                   startup.ClockSetter
-	clockWaiter                   startup.ClockWaiter
-	syncComplete                  chan struct{}
-	blobNotifiers                 *blobNotifierMap
-	blockBeingSynced              *currentlySyncingBlock
-	blobStorage                   *filesystem.BlobStorage
-	lastPublishedLightClientEpoch primitives.Epoch
+	cfg                  *config
+	ctx                  context.Context
+	cancel               context.CancelFunc
+	genesisTime          time.Time
+	head                 *head
+	headLock             sync.RWMutex
+	originBlockRoot      [32]byte // genesis root, or weak subjectivity checkpoint root, depending on how the node is initialized
+	boundaryRoots        [][32]byte
+	checkpointStateCache *cache.CheckpointStateCache
+	initSyncBlocks       map[[32]byte]interfaces.ReadOnlySignedBeaconBlock
+	initSyncBlocksLock   sync.RWMutex
+	wsVerifier           *WeakSubjectivityVerifier
+	clockSetter          startup.ClockSetter
+	clockWaiter          startup.ClockWaiter
+	syncComplete         chan struct{}
+	blobNotifiers        *blobNotifierMap
+	blockBeingSynced     *currentlySyncingBlock
+	blobStorage          *filesystem.BlobStorage
 }
 
 // config options for the service.
@@ -308,7 +305,7 @@ func (s *Service) StartFromSavedState(saved state.BeaconState) error {
 	if err != nil {
 		return errors.Wrap(err, "could not get finalized checkpoint block")
 	}
-	roblock, err := consensus_blocks.NewROBlockWithRoot(finalizedBlock, fRoot)
+	roblock, err := blocks.NewROBlockWithRoot(finalizedBlock, fRoot)
 	if err != nil {
 		return err
 	}
@@ -524,7 +521,7 @@ func (s *Service) saveGenesisData(ctx context.Context, genesisState state.Beacon
 
 	s.cfg.ForkChoiceStore.Lock()
 	defer s.cfg.ForkChoiceStore.Unlock()
-	gb, err := consensus_blocks.NewROBlockWithRoot(genesisBlk, genesisBlkRoot)
+	gb, err := blocks.NewROBlockWithRoot(genesisBlk, genesisBlkRoot)
 	if err != nil {
 		return err
 	}

beacon-chain/core/blocks/exports_test.go

@@ -1,5 +1,5 @@
 package blocks
 
 var ProcessBLSToExecutionChange = processBLSToExecutionChange
-
+var ErrInvalidBLSPrefix = errInvalidBLSPrefix
 var VerifyBlobCommitmentCount = verifyBlobCommitmentCount

beacon-chain/core/blocks/withdrawals.go

@@ -100,8 +100,11 @@ func ValidateBLSToExecutionChange(st state.ReadOnlyBeaconState, signed *ethpb.Si
 	if err != nil {
 		return nil, err
 	}
+	if val == nil {
+		return nil, errors.Wrap(errInvalidWithdrawalCredentials, "validator is nil") // This should not be possible.
+	}
 	cred := val.WithdrawalCredentials
-	if cred[0] != params.BeaconConfig().BLSWithdrawalPrefixByte {
+	if len(cred) < 2 || cred[0] != params.BeaconConfig().BLSWithdrawalPrefixByte {
 		return nil, errInvalidBLSPrefix
 	}
 

beacon-chain/core/blocks/withdrawals_test.go

@@ -113,7 +113,42 @@ func TestProcessBLSToExecutionChange(t *testing.T) {
 		require.NoError(t, err)
 		require.DeepEqual(t, digest[:], val.WithdrawalCredentials)
 	})
+	t.Run("nil validator does not panic", func(t *testing.T) {
+		priv, err := bls.RandKey()
+		require.NoError(t, err)
+		pubkey := priv.PublicKey().Marshal()
 
+		message := &ethpb.BLSToExecutionChange{
+			ToExecutionAddress: []byte{0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13},
+			ValidatorIndex:     0,
+			FromBlsPubkey:      pubkey,
+		}
+
+		registry := []*ethpb.Validator{
+			nil,
+		}
+		st, err := state_native.InitializeFromProtoPhase0(&ethpb.BeaconState{
+			Validators: registry,
+			Fork: &ethpb.Fork{
+				CurrentVersion:  params.BeaconConfig().GenesisForkVersion,
+				PreviousVersion: params.BeaconConfig().GenesisForkVersion,
+			},
+			Slot: params.BeaconConfig().SlotsPerEpoch * 5,
+		})
+		require.NoError(t, err)
+
+		signature, err := signing.ComputeDomainAndSign(st, time.CurrentEpoch(st), message, params.BeaconConfig().DomainBLSToExecutionChange, priv)
+		require.NoError(t, err)
+
+		signed := &ethpb.SignedBLSToExecutionChange{
+			Message:   message,
+			Signature: signature,
+		}
+		_, err = blocks.ValidateBLSToExecutionChange(st, signed)
+		// The state should return an empty validator, even when the validator object in the registry is
+		// nil. This error should return when the withdrawal credentials are invalid or too short.
+		require.ErrorIs(t, err, blocks.ErrInvalidBLSPrefix)
+	})
 	t.Run("non-existent validator", func(t *testing.T) {
 		priv, err := bls.RandKey()
 		require.NoError(t, err)

beacon-chain/core/electra/BUILD.bazel

@@ -41,6 +41,7 @@ go_library(
         "//runtime/version:go_default_library",
         "//time/slots:go_default_library",
         "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
+        "@com_github_ethereum_go_ethereum//common/math:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
         "@com_github_sirupsen_logrus//:go_default_library",
     ],

beacon-chain/core/electra/consolidations.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"fmt"
 
+	"github.com/ethereum/go-ethereum/common/math"
 	"github.com/pkg/errors"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/state"
@@ -156,6 +157,13 @@ func ProcessPendingConsolidations(ctx context.Context, st state.BeaconState) err
 //	    if target_validator.exit_epoch != FAR_FUTURE_EPOCH:
 //	        return
 //
+//	    # Verify the source has been active long enough
+//	    if current_epoch < source_validator.activation_epoch + SHARD_COMMITTEE_PERIOD:
+//	        return
+//
+//	    # Verify the source has no pending withdrawals in the queue
+//	    if get_pending_balance_to_withdraw(state, source_index) > 0:
+//	        return
 //	    # Initiate source validator exit and append pending consolidation
 //	    source_validator.exit_epoch = compute_consolidation_epoch_and_update_churn(
 //	        state, source_validator.effective_balance
@@ -258,6 +266,23 @@ func ProcessConsolidationRequests(ctx context.Context, st state.BeaconState, req
 			continue
 		}
 
+		e, overflow := math.SafeAdd(uint64(srcV.ActivationEpoch), uint64(params.BeaconConfig().ShardCommitteePeriod))
+		if overflow {
+			log.Error("Overflow when adding activation epoch and shard committee period")
+			continue
+		}
+		if uint64(curEpoch) < e {
+			continue
+		}
+		bal, err := st.PendingBalanceToWithdraw(srcIdx)
+		if err != nil {
+			log.WithError(err).Error("failed to fetch pending balance to withdraw")
+			continue
+		}
+		if bal > 0 {
+			continue
+		}
+
 		// Initiate the exit of the source validator.
 		exitEpoch, err := ComputeConsolidationEpochAndUpdateChurn(ctx, st, primitives.Gwei(srcV.EffectiveBalance))
 		if err != nil {

beacon-chain/core/electra/consolidations_test.go

@@ -213,6 +213,7 @@ func TestProcessConsolidationRequests(t *testing.T) {
 			name: "one valid request",
 			state: func() state.BeaconState {
 				st := &eth.BeaconStateElectra{
+					Slot:       params.BeaconConfig().SlotsPerEpoch.Mul(uint64(params.BeaconConfig().ShardCommitteePeriod)),
 					Validators: createValidatorsWithTotalActiveBalance(32000000000000000), // 32M ETH
 				}
 				// Validator scenario setup. See comments in reqs section.
@@ -222,6 +223,12 @@ func TestProcessConsolidationRequests(t *testing.T) {
 				st.Validators[12].ActivationEpoch = params.BeaconConfig().FarFutureEpoch
 				st.Validators[13].ExitEpoch = 10
 				st.Validators[16].ExitEpoch = 10
+				st.PendingPartialWithdrawals = []*eth.PendingPartialWithdrawal{
+					{
+						Index:  17,
+						Amount: 100,
+					},
+				}
 				s, err := state_native.InitializeFromProtoElectra(st)
 				require.NoError(t, err)
 				return s
@@ -287,6 +294,12 @@ func TestProcessConsolidationRequests(t *testing.T) {
 					SourcePubkey:  []byte("val_0"),
 					TargetPubkey:  []byte("val_0"),
 				},
+				// Has pending partial withdrawal
+				{
+					SourceAddress: append(bytesutil.PadTo(nil, 19), byte(0)),
+					SourcePubkey:  []byte("val_17"),
+					TargetPubkey:  []byte("val_1"),
+				},
 				// Valid consolidation request. This should be last to ensure invalid requests do
 				// not end the processing early.
 				{
@@ -347,6 +360,7 @@ func TestProcessConsolidationRequests(t *testing.T) {
 			name: "pending consolidations limit reached during processing",
 			state: func() state.BeaconState {
 				st := &eth.BeaconStateElectra{
+					Slot:                  params.BeaconConfig().SlotsPerEpoch.Mul(uint64(params.BeaconConfig().ShardCommitteePeriod)),
 					Validators:            createValidatorsWithTotalActiveBalance(32000000000000000), // 32M ETH
 					PendingConsolidations: make([]*eth.PendingConsolidation, params.BeaconConfig().PendingConsolidationsLimit-1),
 				}

beacon-chain/core/electra/upgrade.go

@@ -16,36 +16,20 @@ import (
 )
 
 // UpgradeToElectra updates inputs a generic state to return the version Electra state.
+//
+// nolint:dupword
+// Spec code:
 // def upgrade_to_electra(pre: deneb.BeaconState) -> BeaconState:
 //
 //	epoch = deneb.get_current_epoch(pre)
-//	latest_execution_payload_header = ExecutionPayloadHeader(
-//	    parent_hash=pre.latest_execution_payload_header.parent_hash,
-//	    fee_recipient=pre.latest_execution_payload_header.fee_recipient,
-//	    state_root=pre.latest_execution_payload_header.state_root,
-//	    receipts_root=pre.latest_execution_payload_header.receipts_root,
-//	    logs_bloom=pre.latest_execution_payload_header.logs_bloom,
-//	    prev_randao=pre.latest_execution_payload_header.prev_randao,
-//	    block_number=pre.latest_execution_payload_header.block_number,
-//	    gas_limit=pre.latest_execution_payload_header.gas_limit,
-//	    gas_used=pre.latest_execution_payload_header.gas_used,
-//	    timestamp=pre.latest_execution_payload_header.timestamp,
-//	    extra_data=pre.latest_execution_payload_header.extra_data,
-//	    base_fee_per_gas=pre.latest_execution_payload_header.base_fee_per_gas,
-//	    block_hash=pre.latest_execution_payload_header.block_hash,
-//	    transactions_root=pre.latest_execution_payload_header.transactions_root,
-//	    withdrawals_root=pre.latest_execution_payload_header.withdrawals_root,
-//	    blob_gas_used=pre.latest_execution_payload_header.blob_gas_used,
-//	    excess_blob_gas=pre.latest_execution_payload_header.excess_blob_gas,
-//	    deposit_requests_root=Root(),  # [New in Electra:EIP6110]
-//	    withdrawal_requests_root=Root(),  # [New in Electra:EIP7002],
-//	    consolidation_requests_root=Root(),  # [New in Electra:EIP7251]
-//	)
+//	latest_execution_payload_header = pre.latest_execution_payload_header
 //
-//	exit_epochs = [v.exit_epoch for v in pre.validators if v.exit_epoch != FAR_FUTURE_EPOCH]
-//	if not exit_epochs:
-//	    exit_epochs = [get_current_epoch(pre)]
-//	earliest_exit_epoch = max(exit_epochs) + 1
+//	earliest_exit_epoch = compute_activation_exit_epoch(get_current_epoch(pre))
+//	for validator in pre.validators:
+//	    if validator.exit_epoch != FAR_FUTURE_EPOCH:
+//	        if validator.exit_epoch > earliest_exit_epoch:
+//	            earliest_exit_epoch = validator.exit_epoch
+//	earliest_exit_epoch += Epoch(1)
 //
 //	post = BeaconState(
 //	    # Versioning
@@ -120,7 +104,20 @@ import (
 //	))
 //
 //	for index in pre_activation:
-//	    queue_entire_balance_and_reset_validator(post, ValidatorIndex(index))
+//	    balance = post.balances[index]
+//	    post.balances[index] = 0
+//	    validator = post.validators[index]
+//	    validator.effective_balance = 0
+//	    validator.activation_eligibility_epoch = FAR_FUTURE_EPOCH
+//	    # Use bls.G2_POINT_AT_INFINITY as a signature field placeholder
+//	    # and GENESIS_SLOT to distinguish from a pending deposit request
+//	    post.pending_deposits.append(PendingDeposit(
+//	        pubkey=validator.pubkey,
+//	        withdrawal_credentials=validator.withdrawal_credentials,
+//	        amount=balance,
+//	        signature=bls.G2_POINT_AT_INFINITY,
+//	        slot=GENESIS_SLOT,
+//	    ))
 //
 //	# Ensure early adopters of compounding credentials go through the activation churn
 //	for index, validator in enumerate(post.validators):
@@ -187,7 +184,7 @@ func UpgradeToElectra(beaconState state.BeaconState) (state.BeaconState, error)
 	}
 
 	// [New in Electra:EIP7251]
-	earliestExitEpoch := time.CurrentEpoch(beaconState)
+	earliestExitEpoch := helpers.ActivationExitEpoch(time.CurrentEpoch(beaconState))
 	preActivationIndices := make([]primitives.ValidatorIndex, 0)
 	compoundWithdrawalIndices := make([]primitives.ValidatorIndex, 0)
 	if err = beaconState.ReadFromEveryValidator(func(index int, val state.ReadOnlyValidator) error {

beacon-chain/core/electra/upgrade_test.go

@@ -159,7 +159,7 @@ func TestUpgradeToElectra(t *testing.T) {
 
 	eee, err := mSt.EarliestExitEpoch()
 	require.NoError(t, err)
-	require.Equal(t, primitives.Epoch(1), eee)
+	require.Equal(t, helpers.ActivationExitEpoch(primitives.Epoch(1)), eee)
 
 	cbtc, err := mSt.ConsolidationBalanceToConsume()
 	require.NoError(t, err)

beacon-chain/core/light-client/BUILD.bazel

@@ -6,19 +6,22 @@ go_library(
     importpath = "github.com/prysmaticlabs/prysm/v5/beacon-chain/core/light-client",
     visibility = ["//visibility:public"],
     deps = [
+        "//beacon-chain/execution:go_default_library",
         "//beacon-chain/state:go_default_library",
         "//config/fieldparams:go_default_library",
         "//config/params:go_default_library",
         "//consensus-types:go_default_library",
         "//consensus-types/blocks:go_default_library",
         "//consensus-types/interfaces:go_default_library",
+        "//consensus-types/light-client:go_default_library",
+        "//consensus-types/primitives:go_default_library",
         "//encoding/ssz:go_default_library",
         "//proto/engine/v1:go_default_library",
-        "//proto/eth/v1:go_default_library",
-        "//proto/eth/v2:go_default_library",
+        "//proto/prysm/v1alpha1:go_default_library",
         "//runtime/version:go_default_library",
         "//time/slots:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
+        "@org_golang_google_protobuf//proto:go_default_library",
     ],
 )
 
@@ -28,10 +31,14 @@ go_test(
     deps = [
         ":go_default_library",
         "//config/fieldparams:go_default_library",
+        "//config/params:go_default_library",
         "//consensus-types:go_default_library",
         "//consensus-types/blocks:go_default_library",
+        "//consensus-types/light-client:go_default_library",
+        "//consensus-types/primitives:go_default_library",
         "//encoding/ssz:go_default_library",
         "//proto/engine/v1:go_default_library",
+        "//proto/prysm/v1alpha1:go_default_library",
         "//testing/require:go_default_library",
         "//testing/util:go_default_library",
         "@com_github_pkg_errors//:go_default_library",

beacon-chain/das/cache.go

@@ -93,7 +93,7 @@ func (e *cacheEntry) filter(root [32]byte, kc safeCommitmentArray) ([]blocks.ROB
 		return nil, nil
 	}
 	scs := make([]blocks.ROBlob, 0, kc.count())
-	for i := uint64(0); i < fieldparams.MaxBlobsPerBlock; i++ {
+	for i := range uint64(fieldparams.MaxBlobsPerBlock) {
 		// We already have this blob, we don't need to write it or validate it.
 		if e.diskSummary.HasIndex(i) {
 			continue

beacon-chain/db/iface/BUILD.bazel

@@ -18,7 +18,6 @@ go_library(
         "//consensus-types/primitives:go_default_library",
         "//monitoring/backup:go_default_library",
         "//proto/dbval:go_default_library",
-        "//proto/eth/v2:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
         "@com_github_ethereum_go_ethereum//common:go_default_library",
     ],

beacon-chain/db/iface/interface.go

@@ -7,8 +7,6 @@ import (
 	"context"
 	"io"
 
-	ethpbv2 "github.com/prysmaticlabs/prysm/v5/proto/eth/v2"
-
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/db/filters"
 	slashertypes "github.com/prysmaticlabs/prysm/v5/beacon-chain/slasher/types"
@@ -59,8 +57,9 @@ type ReadOnlyDatabase interface {
 	FeeRecipientByValidatorID(ctx context.Context, id primitives.ValidatorIndex) (common.Address, error)
 	RegistrationByValidatorID(ctx context.Context, id primitives.ValidatorIndex) (*ethpb.ValidatorRegistrationV1, error)
 	// light client operations
-	LightClientUpdates(ctx context.Context, startPeriod, endPeriod uint64) (map[uint64]*ethpbv2.LightClientUpdateWithVersion, error)
-	LightClientUpdate(ctx context.Context, period uint64) (*ethpbv2.LightClientUpdateWithVersion, error)
+	LightClientUpdates(ctx context.Context, startPeriod, endPeriod uint64) (map[uint64]interfaces.LightClientUpdate, error)
+	LightClientUpdate(ctx context.Context, period uint64) (interfaces.LightClientUpdate, error)
+	LightClientBootstrap(ctx context.Context, blockRoot []byte) (interfaces.LightClientBootstrap, error)
 
 	// origin checkpoint sync support
 	OriginCheckpointBlockRoot(ctx context.Context) ([32]byte, error)
@@ -98,7 +97,8 @@ type NoHeadAccessDatabase interface {
 	SaveFeeRecipientsByValidatorIDs(ctx context.Context, ids []primitives.ValidatorIndex, addrs []common.Address) error
 	SaveRegistrationsByValidatorIDs(ctx context.Context, ids []primitives.ValidatorIndex, regs []*ethpb.ValidatorRegistrationV1) error
 	// light client operations
-	SaveLightClientUpdate(ctx context.Context, period uint64, update *ethpbv2.LightClientUpdateWithVersion) error
+	SaveLightClientUpdate(ctx context.Context, period uint64, update interfaces.LightClientUpdate) error
+	SaveLightClientBootstrap(ctx context.Context, blockRoot []byte, bootstrap interfaces.LightClientBootstrap) error
 
 	CleanUpDirtyStates(ctx context.Context, slotsPerArchivedPoint primitives.Slot) error
 }

beacon-chain/db/kv/BUILD.bazel

@@ -44,6 +44,7 @@ go_library(
         "//config/params:go_default_library",
         "//consensus-types/blocks:go_default_library",
         "//consensus-types/interfaces:go_default_library",
+        "//consensus-types/light-client:go_default_library",
         "//consensus-types/primitives:go_default_library",
         "//container/slice:go_default_library",
         "//encoding/bytesutil:go_default_library",
@@ -53,7 +54,6 @@ go_library(
         "//monitoring/tracing:go_default_library",
         "//monitoring/tracing/trace:go_default_library",
         "//proto/dbval:go_default_library",
-        "//proto/eth/v2:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
         "//runtime/version:go_default_library",
         "//time:go_default_library",
@@ -112,18 +112,18 @@ go_test(
         "//config/params:go_default_library",
         "//consensus-types/blocks:go_default_library",
         "//consensus-types/interfaces:go_default_library",
+        "//consensus-types/light-client:go_default_library",
         "//consensus-types/primitives:go_default_library",
         "//encoding/bytesutil:go_default_library",
         "//proto/dbval:go_default_library",
         "//proto/engine/v1:go_default_library",
-        "//proto/eth/v1:go_default_library",
-        "//proto/eth/v2:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
         "//proto/testing:go_default_library",
         "//runtime/version:go_default_library",
         "//testing/assert:go_default_library",
         "//testing/require:go_default_library",
         "//testing/util:go_default_library",
+        "//time/slots:go_default_library",
         "@com_github_ethereum_go_ethereum//common:go_default_library",
         "@com_github_golang_snappy//:go_default_library",
         "@com_github_pkg_errors//:go_default_library",

beacon-chain/db/kv/kv.go

@@ -108,6 +108,7 @@ var Buckets = [][]byte{
 	stateSummaryBucket,
 	stateValidatorsBucket,
 	lightClientUpdatesBucket,
+	lightClientBootstrapBucket,
 	// Indices buckets.
 	blockSlotIndicesBucket,
 	stateSlotIndicesBucket,

beacon-chain/db/kv/lightclient.go

@@ -5,35 +5,126 @@ import (
 	"encoding/binary"
 	"fmt"
 
+	"github.com/golang/snappy"
+	"github.com/pkg/errors"
+	"github.com/prysmaticlabs/prysm/v5/consensus-types/interfaces"
+	light_client "github.com/prysmaticlabs/prysm/v5/consensus-types/light-client"
 	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
 	"github.com/prysmaticlabs/prysm/v5/monitoring/tracing/trace"
-	ethpbv2 "github.com/prysmaticlabs/prysm/v5/proto/eth/v2"
+	ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/v5/runtime/version"
 	bolt "go.etcd.io/bbolt"
+	"google.golang.org/protobuf/proto"
 )
 
-func (s *Store) SaveLightClientUpdate(ctx context.Context, period uint64, update *ethpbv2.LightClientUpdateWithVersion) error {
-	ctx, span := trace.StartSpan(ctx, "BeaconDB.saveLightClientUpdate")
+func (s *Store) SaveLightClientUpdate(ctx context.Context, period uint64, update interfaces.LightClientUpdate) error {
+	_, span := trace.StartSpan(ctx, "BeaconDB.SaveLightClientUpdate")
 	defer span.End()
 
 	return s.db.Update(func(tx *bolt.Tx) error {
 		bkt := tx.Bucket(lightClientUpdatesBucket)
-		updateMarshalled, err := encode(ctx, update)
+		enc, err := encodeLightClientUpdate(update)
 		if err != nil {
 			return err
 		}
-		return bkt.Put(bytesutil.Uint64ToBytesBigEndian(period), updateMarshalled)
+		return bkt.Put(bytesutil.Uint64ToBytesBigEndian(period), enc)
 	})
 }
 
-func (s *Store) LightClientUpdates(ctx context.Context, startPeriod, endPeriod uint64) (map[uint64]*ethpbv2.LightClientUpdateWithVersion, error) {
-	ctx, span := trace.StartSpan(ctx, "BeaconDB.LightClientUpdates")
+func (s *Store) SaveLightClientBootstrap(ctx context.Context, blockRoot []byte, bootstrap interfaces.LightClientBootstrap) error {
+	_, span := trace.StartSpan(ctx, "BeaconDB.SaveLightClientBootstrap")
+	defer span.End()
+
+	return s.db.Update(func(tx *bolt.Tx) error {
+		bkt := tx.Bucket(lightClientBootstrapBucket)
+		enc, err := encodeLightClientBootstrap(bootstrap)
+		if err != nil {
+			return err
+		}
+		return bkt.Put(blockRoot, enc)
+	})
+}
+
+func (s *Store) LightClientBootstrap(ctx context.Context, blockRoot []byte) (interfaces.LightClientBootstrap, error) {
+	_, span := trace.StartSpan(ctx, "BeaconDB.LightClientBootstrap")
+	defer span.End()
+
+	var bootstrap interfaces.LightClientBootstrap
+	err := s.db.View(func(tx *bolt.Tx) error {
+		bkt := tx.Bucket(lightClientBootstrapBucket)
+		enc := bkt.Get(blockRoot)
+		if enc == nil {
+			return nil
+		}
+		var err error
+		bootstrap, err = decodeLightClientBootstrap(enc)
+		return err
+	})
+	return bootstrap, err
+}
+
+func encodeLightClientBootstrap(bootstrap interfaces.LightClientBootstrap) ([]byte, error) {
+	key, err := keyForLightClientUpdate(bootstrap.Version())
+	if err != nil {
+		return nil, err
+	}
+	enc, err := bootstrap.MarshalSSZ()
+	if err != nil {
+		return nil, errors.Wrap(err, "could not marshal light client bootstrap")
+	}
+	fullEnc := make([]byte, len(key)+len(enc))
+	copy(fullEnc, key)
+	copy(fullEnc[len(key):], enc)
+	return snappy.Encode(nil, fullEnc), nil
+}
+
+func decodeLightClientBootstrap(enc []byte) (interfaces.LightClientBootstrap, error) {
+	var err error
+	enc, err = snappy.Decode(nil, enc)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not snappy decode light client bootstrap")
+	}
+	var m proto.Message
+	switch {
+	case hasAltairKey(enc):
+		bootstrap := &ethpb.LightClientBootstrapAltair{}
+		if err := bootstrap.UnmarshalSSZ(enc[len(altairKey):]); err != nil {
+			return nil, errors.Wrap(err, "could not unmarshal Altair light client bootstrap")
+		}
+		m = bootstrap
+	case hasCapellaKey(enc):
+		bootstrap := &ethpb.LightClientBootstrapCapella{}
+		if err := bootstrap.UnmarshalSSZ(enc[len(capellaKey):]); err != nil {
+			return nil, errors.Wrap(err, "could not unmarshal Capella light client bootstrap")
+		}
+		m = bootstrap
+	case hasDenebKey(enc):
+		bootstrap := &ethpb.LightClientBootstrapDeneb{}
+		if err := bootstrap.UnmarshalSSZ(enc[len(denebKey):]); err != nil {
+			return nil, errors.Wrap(err, "could not unmarshal Deneb light client bootstrap")
+		}
+		m = bootstrap
+	case hasElectraKey(enc):
+		bootstrap := &ethpb.LightClientBootstrapElectra{}
+		if err := bootstrap.UnmarshalSSZ(enc[len(electraKey):]); err != nil {
+			return nil, errors.Wrap(err, "could not unmarshal Electra light client bootstrap")
+		}
+		m = bootstrap
+	default:
+		return nil, errors.New("decoding of saved light client bootstrap is unsupported")
+	}
+	return light_client.NewWrappedBootstrap(m)
+}
+
+func (s *Store) LightClientUpdates(ctx context.Context, startPeriod, endPeriod uint64) (map[uint64]interfaces.LightClientUpdate, error) {
+	_, span := trace.StartSpan(ctx, "BeaconDB.LightClientUpdates")
 	defer span.End()
 
 	if startPeriod > endPeriod {
 		return nil, fmt.Errorf("start period %d is greater than end period %d", startPeriod, endPeriod)
 	}
 
-	updates := make(map[uint64]*ethpbv2.LightClientUpdateWithVersion)
+	updates := make(map[uint64]interfaces.LightClientUpdate)
 	err := s.db.View(func(tx *bolt.Tx) error {
 		bkt := tx.Bucket(lightClientUpdatesBucket)
 		c := bkt.Cursor()
@@ -46,11 +137,11 @@ func (s *Store) LightClientUpdates(ctx context.Context, startPeriod, endPeriod u
 		for k, v := c.Seek(bytesutil.Uint64ToBytesBigEndian(startPeriod)); k != nil && binary.BigEndian.Uint64(k) <= endPeriod; k, v = c.Next() {
 			currentPeriod := binary.BigEndian.Uint64(k)
 
-			var update ethpbv2.LightClientUpdateWithVersion
-			if err := decode(ctx, v, &update); err != nil {
+			update, err := decodeLightClientUpdate(v)
+			if err != nil {
 				return err
 			}
-			updates[currentPeriod] = &update
+			updates[currentPeriod] = update
 		}
 
 		return nil
@@ -62,18 +153,88 @@ func (s *Store) LightClientUpdates(ctx context.Context, startPeriod, endPeriod u
 	return updates, err
 }
 
-func (s *Store) LightClientUpdate(ctx context.Context, period uint64) (*ethpbv2.LightClientUpdateWithVersion, error) {
-	ctx, span := trace.StartSpan(ctx, "BeaconDB.LightClientUpdate")
+func (s *Store) LightClientUpdate(ctx context.Context, period uint64) (interfaces.LightClientUpdate, error) {
+	_, span := trace.StartSpan(ctx, "BeaconDB.LightClientUpdate")
 	defer span.End()
 
-	var update ethpbv2.LightClientUpdateWithVersion
+	var update interfaces.LightClientUpdate
 	err := s.db.View(func(tx *bolt.Tx) error {
 		bkt := tx.Bucket(lightClientUpdatesBucket)
 		updateBytes := bkt.Get(bytesutil.Uint64ToBytesBigEndian(period))
 		if updateBytes == nil {
 			return nil
 		}
-		return decode(ctx, updateBytes, &update)
+		var err error
+		update, err = decodeLightClientUpdate(updateBytes)
+		return err
 	})
-	return &update, err
+	return update, err
+}
+
+func encodeLightClientUpdate(update interfaces.LightClientUpdate) ([]byte, error) {
+	key, err := keyForLightClientUpdate(update.Version())
+	if err != nil {
+		return nil, err
+	}
+	enc, err := update.MarshalSSZ()
+	if err != nil {
+		return nil, errors.Wrap(err, "could not marshal light client update")
+	}
+	fullEnc := make([]byte, len(key)+len(enc))
+	copy(fullEnc, key)
+	copy(fullEnc[len(key):], enc)
+	return snappy.Encode(nil, fullEnc), nil
+}
+
+func decodeLightClientUpdate(enc []byte) (interfaces.LightClientUpdate, error) {
+	var err error
+	enc, err = snappy.Decode(nil, enc)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not snappy decode light client update")
+	}
+	var m proto.Message
+	switch {
+	case hasAltairKey(enc):
+		update := &ethpb.LightClientUpdateAltair{}
+		if err := update.UnmarshalSSZ(enc[len(altairKey):]); err != nil {
+			return nil, errors.Wrap(err, "could not unmarshal Altair light client update")
+		}
+		m = update
+	case hasCapellaKey(enc):
+		update := &ethpb.LightClientUpdateCapella{}
+		if err := update.UnmarshalSSZ(enc[len(capellaKey):]); err != nil {
+			return nil, errors.Wrap(err, "could not unmarshal Capella light client update")
+		}
+		m = update
+	case hasDenebKey(enc):
+		update := &ethpb.LightClientUpdateDeneb{}
+		if err := update.UnmarshalSSZ(enc[len(denebKey):]); err != nil {
+			return nil, errors.Wrap(err, "could not unmarshal Deneb light client update")
+		}
+		m = update
+	case hasElectraKey(enc):
+		update := &ethpb.LightClientUpdateElectra{}
+		if err := update.UnmarshalSSZ(enc[len(electraKey):]); err != nil {
+			return nil, errors.Wrap(err, "could not unmarshal Electra light client update")
+		}
+		m = update
+	default:
+		return nil, errors.New("decoding of saved light client update is unsupported")
+	}
+	return light_client.NewWrappedUpdate(m)
+}
+
+func keyForLightClientUpdate(v int) ([]byte, error) {
+	switch v {
+	case version.Electra:
+		return electraKey, nil
+	case version.Deneb:
+		return denebKey, nil
+	case version.Capella:
+		return capellaKey, nil
+	case version.Altair:
+		return altairKey, nil
+	default:
+		return nil, fmt.Errorf("unsupported light client update version %s", version.String(v))
+	}
 }

beacon-chain/db/kv/schema.go

@@ -18,7 +18,8 @@ var (
 	registrationBucket    = []byte("registration")
 
 	// Light Client Updates Bucket
-	lightClientUpdatesBucket = []byte("light-client-updates")
+	lightClientUpdatesBucket   = []byte("light-client-updates")
+	lightClientBootstrapBucket = []byte("light-client-bootstrap")
 
 	// Deprecated: This bucket was migrated in PR 6461. Do not use, except for migrations.
 	slotsHasObjectBucket = []byte("slots-has-objects")

beacon-chain/deterministic-genesis/BUILD.bazel

@@ -1,24 +0,0 @@
-load("@prysm//tools/go:def.bzl", "go_library")
-
-go_library(
-    name = "go_default_library",
-    srcs = [
-        "log.go",
-        "service.go",
-    ],
-    importpath = "github.com/prysmaticlabs/prysm/v5/beacon-chain/deterministic-genesis",
-    visibility = ["//beacon-chain:__subpackages__"],
-    deps = [
-        "//beacon-chain/cache:go_default_library",
-        "//beacon-chain/db:go_default_library",
-        "//beacon-chain/execution:go_default_library",
-        "//beacon-chain/state:go_default_library",
-        "//beacon-chain/state/state-native:go_default_library",
-        "//consensus-types/primitives:go_default_library",
-        "//proto/prysm/v1alpha1:go_default_library",
-        "//runtime:go_default_library",
-        "//runtime/interop:go_default_library",
-        "//time/slots:go_default_library",
-        "@com_github_sirupsen_logrus//:go_default_library",
-    ],
-)

beacon-chain/deterministic-genesis/log.go

@@ -1,7 +0,0 @@
-package interopcoldstart
-
-import (
-	"github.com/sirupsen/logrus"
-)
-
-var log = logrus.WithField("prefix", "deterministic-genesis")

beacon-chain/deterministic-genesis/service.go

@@ -1,206 +0,0 @@
-// Package interopcoldstart allows for spinning up a deterministic-genesis
-// local chain without the need for eth1 deposits useful for
-// local client development and interoperability testing.
-package interopcoldstart
-
-import (
-	"context"
-	"math/big"
-	"os"
-	"time"
-
-	"github.com/prysmaticlabs/prysm/v5/beacon-chain/cache"
-	"github.com/prysmaticlabs/prysm/v5/beacon-chain/db"
-	"github.com/prysmaticlabs/prysm/v5/beacon-chain/execution"
-	"github.com/prysmaticlabs/prysm/v5/beacon-chain/state"
-	state_native "github.com/prysmaticlabs/prysm/v5/beacon-chain/state/state-native"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
-	ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/v5/runtime"
-	"github.com/prysmaticlabs/prysm/v5/runtime/interop"
-	"github.com/prysmaticlabs/prysm/v5/time/slots"
-)
-
-var _ runtime.Service = (*Service)(nil)
-var _ cache.FinalizedFetcher = (*Service)(nil)
-var _ execution.ChainStartFetcher = (*Service)(nil)
-
-// Service spins up an client interoperability service that handles responsibilities such
-// as kickstarting a genesis state for the beacon node from cli flags or a genesis.ssz file.
-type Service struct {
-	cfg                *Config
-	ctx                context.Context
-	cancel             context.CancelFunc
-	chainStartDeposits []*ethpb.Deposit
-}
-
-// All of these methods are stubs as they are not used by a node running with deterministic-genesis.
-
-func (s *Service) AllDepositContainers(ctx context.Context) []*ethpb.DepositContainer {
-	log.Errorf("AllDepositContainers should not be called")
-	return nil
-}
-
-func (s *Service) InsertPendingDeposit(ctx context.Context, d *ethpb.Deposit, blockNum uint64, index int64, depositRoot [32]byte) {
-	log.Errorf("InsertPendingDeposit should not be called")
-}
-
-func (s *Service) PendingDeposits(ctx context.Context, untilBlk *big.Int) []*ethpb.Deposit {
-	log.Errorf("PendingDeposits should not be called")
-	return nil
-}
-
-func (s *Service) PendingContainers(ctx context.Context, untilBlk *big.Int) []*ethpb.DepositContainer {
-	log.Errorf("PendingContainers should not be called")
-	return nil
-}
-
-func (s *Service) PrunePendingDeposits(ctx context.Context, merkleTreeIndex int64) {
-	log.Errorf("PrunePendingDeposits should not be called")
-}
-
-func (s *Service) PruneProofs(ctx context.Context, untilDepositIndex int64) error {
-	log.Errorf("PruneProofs should not be called")
-	return nil
-}
-
-// Config options for the interop service.
-type Config struct {
-	GenesisTime   uint64
-	NumValidators uint64
-	BeaconDB      db.HeadAccessDatabase
-	DepositCache  cache.DepositCache
-	GenesisPath   string
-}
-
-// NewService is an interoperability testing service to inject a deterministically generated genesis state
-// into the beacon chain database and running services at start up. This service should not be used in production
-// as it does not have any value other than ease of use for testing purposes.
-func NewService(ctx context.Context, cfg *Config) *Service {
-	ctx, cancel := context.WithCancel(ctx)
-
-	return &Service{
-		cfg:    cfg,
-		ctx:    ctx,
-		cancel: cancel,
-	}
-}
-
-// Start initializes the genesis state from configured flags.
-func (s *Service) Start() {
-	log.Warn("Saving generated genesis state in database for interop testing")
-
-	if s.cfg.GenesisPath != "" {
-		data, err := os.ReadFile(s.cfg.GenesisPath)
-		if err != nil {
-			log.WithError(err).Fatal("Could not read pre-loaded state")
-		}
-		genesisState := &ethpb.BeaconState{}
-		if err := genesisState.UnmarshalSSZ(data); err != nil {
-			log.WithError(err).Fatal("Could not unmarshal pre-loaded state")
-		}
-		genesisTrie, err := state_native.InitializeFromProtoPhase0(genesisState)
-		if err != nil {
-			log.WithError(err).Fatal("Could not get state trie")
-		}
-		if err := s.saveGenesisState(s.ctx, genesisTrie); err != nil {
-			log.WithError(err).Fatal("Could not save interop genesis state")
-		}
-		return
-	}
-
-	// Save genesis state in db
-	genesisState, _, err := interop.GenerateGenesisState(s.ctx, s.cfg.GenesisTime, s.cfg.NumValidators)
-	if err != nil {
-		log.WithError(err).Fatal("Could not generate interop genesis state")
-	}
-	genesisTrie, err := state_native.InitializeFromProtoPhase0(genesisState)
-	if err != nil {
-		log.WithError(err).Fatal("Could not get state trie")
-	}
-	if s.cfg.GenesisTime == 0 {
-		// Generated genesis time; fetch it
-		s.cfg.GenesisTime = genesisTrie.GenesisTime()
-	}
-	gRoot, err := genesisTrie.HashTreeRoot(s.ctx)
-	if err != nil {
-		log.WithError(err).Fatal("Could not hash tree root genesis state")
-	}
-	go slots.CountdownToGenesis(s.ctx, time.Unix(int64(s.cfg.GenesisTime), 0), s.cfg.NumValidators, gRoot)
-
-	if err := s.saveGenesisState(s.ctx, genesisTrie); err != nil {
-		log.WithError(err).Fatal("Could not save interop genesis state")
-	}
-}
-
-// Stop does nothing.
-func (_ *Service) Stop() error {
-	return nil
-}
-
-// Status always returns nil.
-func (_ *Service) Status() error {
-	return nil
-}
-
-// AllDeposits mocks out the deposit cache functionality for interop.
-func (_ *Service) AllDeposits(_ context.Context, _ *big.Int) []*ethpb.Deposit {
-	return []*ethpb.Deposit{}
-}
-
-// ChainStartEth1Data mocks out the powchain functionality for interop.
-func (_ *Service) ChainStartEth1Data() *ethpb.Eth1Data {
-	return &ethpb.Eth1Data{}
-}
-
-// PreGenesisState returns an empty beacon state.
-func (_ *Service) PreGenesisState() state.BeaconState {
-	s, err := state_native.InitializeFromProtoPhase0(&ethpb.BeaconState{})
-	if err != nil {
-		panic("could not initialize state")
-	}
-	return s
-}
-
-// ClearPreGenesisData --
-func (_ *Service) ClearPreGenesisData() {
-	// no-op
-}
-
-// DepositByPubkey mocks out the deposit cache functionality for interop.
-func (_ *Service) DepositByPubkey(_ context.Context, _ []byte) (*ethpb.Deposit, *big.Int) {
-	return &ethpb.Deposit{}, nil
-}
-
-// DepositsNumberAndRootAtHeight mocks out the deposit cache functionality for interop.
-func (_ *Service) DepositsNumberAndRootAtHeight(_ context.Context, _ *big.Int) (uint64, [32]byte) {
-	return 0, [32]byte{}
-}
-
-// FinalizedDeposits mocks out the deposit cache functionality for interop.
-func (_ *Service) FinalizedDeposits(ctx context.Context) (cache.FinalizedDeposits, error) {
-	return nil, nil
-}
-
-// NonFinalizedDeposits mocks out the deposit cache functionality for interop.
-func (_ *Service) NonFinalizedDeposits(_ context.Context, _ int64, _ *big.Int) []*ethpb.Deposit {
-	return []*ethpb.Deposit{}
-}
-
-func (s *Service) saveGenesisState(ctx context.Context, genesisState state.BeaconState) error {
-	if err := s.cfg.BeaconDB.SaveGenesisData(ctx, genesisState); err != nil {
-		return err
-	}
-
-	s.chainStartDeposits = make([]*ethpb.Deposit, genesisState.NumValidators())
-
-	for i := primitives.ValidatorIndex(0); uint64(i) < uint64(genesisState.NumValidators()); i++ {
-		pk := genesisState.PubkeyAtIndex(i)
-		s.chainStartDeposits[i] = &ethpb.Deposit{
-			Data: &ethpb.Deposit_Data{
-				PublicKey: pk[:],
-			},
-		}
-	}
-	return nil
-}

beacon-chain/execution/engine_client.go

@@ -801,7 +801,7 @@ func tDStringToUint256(td string) (*uint256.Int, error) {
 	return i, nil
 }
 
-func buildEmptyExecutionPayload(v int) (proto.Message, error) {
+func EmptyExecutionPayload(v int) (proto.Message, error) {
 	switch v {
 	case version.Bellatrix:
 		return &pb.ExecutionPayload{
@@ -849,6 +849,53 @@ func buildEmptyExecutionPayload(v int) (proto.Message, error) {
 	}
 }
 
+func EmptyExecutionPayloadHeader(v int) (proto.Message, error) {
+	switch v {
+	case version.Bellatrix:
+		return &pb.ExecutionPayloadHeader{
+			ParentHash:    make([]byte, fieldparams.RootLength),
+			FeeRecipient:  make([]byte, fieldparams.FeeRecipientLength),
+			StateRoot:     make([]byte, fieldparams.RootLength),
+			ReceiptsRoot:  make([]byte, fieldparams.RootLength),
+			LogsBloom:     make([]byte, fieldparams.LogsBloomLength),
+			PrevRandao:    make([]byte, fieldparams.RootLength),
+			ExtraData:     make([]byte, 0),
+			BaseFeePerGas: make([]byte, fieldparams.RootLength),
+			BlockHash:     make([]byte, fieldparams.RootLength),
+		}, nil
+	case version.Capella:
+		return &pb.ExecutionPayloadHeaderCapella{
+			ParentHash:       make([]byte, fieldparams.RootLength),
+			FeeRecipient:     make([]byte, fieldparams.FeeRecipientLength),
+			StateRoot:        make([]byte, fieldparams.RootLength),
+			ReceiptsRoot:     make([]byte, fieldparams.RootLength),
+			LogsBloom:        make([]byte, fieldparams.LogsBloomLength),
+			PrevRandao:       make([]byte, fieldparams.RootLength),
+			ExtraData:        make([]byte, 0),
+			BaseFeePerGas:    make([]byte, fieldparams.RootLength),
+			BlockHash:        make([]byte, fieldparams.RootLength),
+			TransactionsRoot: make([]byte, fieldparams.RootLength),
+			WithdrawalsRoot:  make([]byte, fieldparams.RootLength),
+		}, nil
+	case version.Deneb, version.Electra:
+		return &pb.ExecutionPayloadHeaderDeneb{
+			ParentHash:       make([]byte, fieldparams.RootLength),
+			FeeRecipient:     make([]byte, fieldparams.FeeRecipientLength),
+			StateRoot:        make([]byte, fieldparams.RootLength),
+			ReceiptsRoot:     make([]byte, fieldparams.RootLength),
+			LogsBloom:        make([]byte, fieldparams.LogsBloomLength),
+			PrevRandao:       make([]byte, fieldparams.RootLength),
+			ExtraData:        make([]byte, 0),
+			BaseFeePerGas:    make([]byte, fieldparams.RootLength),
+			BlockHash:        make([]byte, fieldparams.RootLength),
+			TransactionsRoot: make([]byte, fieldparams.RootLength),
+			WithdrawalsRoot:  make([]byte, fieldparams.RootLength),
+		}, nil
+	default:
+		return nil, errors.Wrapf(ErrUnsupportedVersion, "version=%s", version.String(v))
+	}
+}
+
 func toBlockNumArg(number *big.Int) string {
 	if number == nil {
 		return "latest"

beacon-chain/execution/payload_body.go

@@ -205,7 +205,7 @@ func (r *blindedBlockReconstructor) requestBodiesByHash(ctx context.Context, cli
 func (r *blindedBlockReconstructor) payloadForHeader(header interfaces.ExecutionData, v int) (proto.Message, error) {
 	bodyKey := bytesutil.ToBytes32(header.BlockHash())
 	if bodyKey == params.BeaconConfig().ZeroHash {
-		payload, err := buildEmptyExecutionPayload(v)
+		payload, err := EmptyExecutionPayload(v)
 		if err != nil {
 			return nil, errors.Wrapf(err, "failed to reconstruct payload for body hash %#x", bodyKey)
 		}

beacon-chain/forkchoice/doubly-linked-tree/optimistic_sync.go

@@ -23,6 +23,9 @@ func (s *Store) setOptimisticToInvalid(ctx context.Context, root, parentRoot, la
 		if node == nil {
 			return invalidRoots, errors.Wrap(ErrNilNode, "could not set node to invalid")
 		}
+		if node.parent == nil {
+			return invalidRoots, errors.New("attempting to set the root node to invalid")
+		}
 		if node.parent.root != parentRoot {
 			return invalidRoots, errInvalidParentRoot
 		}

beacon-chain/forkchoice/doubly-linked-tree/optimistic_sync_test.go

@@ -385,6 +385,13 @@ func TestSetOptimisticToInvalid_ForkAtMerge_bis(t *testing.T) {
 	require.DeepEqual(t, roots, [][32]byte{{'b'}, {'c'}, {'d'}, {'e'}})
 }
 
+func TestSetOptimisticToInvalid_InvalidRoot(t *testing.T) {
+	ctx := context.Background()
+	f := setup(1, 1)
+	_, err := f.SetOptimisticToInvalid(ctx, [32]byte{}, [32]byte{}, [32]byte{})
+	require.ErrorContains(t, "attempting to set the root node to invalid", err)
+}
+
 func TestSetOptimisticToValid(t *testing.T) {
 	f := setup(1, 1)
 	op, err := f.IsOptimistic([32]byte{})

beacon-chain/node/BUILD.bazel

@@ -26,7 +26,6 @@ go_library(
         "//beacon-chain/db/filesystem:go_default_library",
         "//beacon-chain/db/kv:go_default_library",
         "//beacon-chain/db/slasherkv:go_default_library",
-        "//beacon-chain/deterministic-genesis:go_default_library",
         "//beacon-chain/execution:go_default_library",
         "//beacon-chain/forkchoice:go_default_library",
         "//beacon-chain/forkchoice/doubly-linked-tree:go_default_library",
@@ -92,12 +91,9 @@ go_test(
         "//cmd:go_default_library",
         "//cmd/beacon-chain/flags:go_default_library",
         "//config/features:go_default_library",
-        "//config/fieldparams:go_default_library",
         "//config/params:go_default_library",
         "//consensus-types/primitives:go_default_library",
-        "//proto/prysm/v1alpha1:go_default_library",
         "//runtime:go_default_library",
-        "//runtime/interop:go_default_library",
         "//testing/assert:go_default_library",
         "//testing/require:go_default_library",
         "@com_github_ethereum_go_ethereum//common:go_default_library",

beacon-chain/node/config.go

@@ -144,23 +144,6 @@ func configureNetwork(cliCtx *cli.Context) {
 	}
 }
 
-func configureInteropConfig(cliCtx *cli.Context) error {
-	// an explicit chain config was specified, don't mess with it
-	if cliCtx.IsSet(cmd.ChainConfigFileFlag.Name) {
-		return nil
-	}
-	genTimeIsSet := cliCtx.IsSet(flags.InteropGenesisTimeFlag.Name)
-	numValsIsSet := cliCtx.IsSet(flags.InteropNumValidatorsFlag.Name)
-	votesIsSet := cliCtx.IsSet(flags.InteropMockEth1DataVotesFlag.Name)
-
-	if genTimeIsSet || numValsIsSet || votesIsSet {
-		if err := params.SetActive(params.InteropConfig().Copy()); err != nil {
-			return err
-		}
-	}
-	return nil
-}
-
 func configureExecutionSetting(cliCtx *cli.Context) error {
 	if cliCtx.IsSet(flags.TerminalTotalDifficultyOverride.Name) {
 		c := params.BeaconConfig()

beacon-chain/node/config_test.go

@@ -169,66 +169,6 @@ func TestConfigureNetwork_ConfigFile(t *testing.T) {
 	require.NoError(t, os.Remove("flags_test.yaml"))
 }
 
-func TestConfigureInterop(t *testing.T) {
-	params.SetupTestConfigCleanup(t)
-
-	tests := []struct {
-		name       string
-		flagSetter func() *cli.Context
-		configName string
-	}{
-		{
-			"nothing set",
-			func() *cli.Context {
-				app := cli.App{}
-				set := flag.NewFlagSet("test", 0)
-				return cli.NewContext(&app, set, nil)
-			},
-			"mainnet",
-		},
-		{
-			"mock votes set",
-			func() *cli.Context {
-				app := cli.App{}
-				set := flag.NewFlagSet("test", 0)
-				set.Bool(flags.InteropMockEth1DataVotesFlag.Name, false, "")
-				assert.NoError(t, set.Set(flags.InteropMockEth1DataVotesFlag.Name, "true"))
-				return cli.NewContext(&app, set, nil)
-			},
-			"interop",
-		},
-		{
-			"validators set",
-			func() *cli.Context {
-				app := cli.App{}
-				set := flag.NewFlagSet("test", 0)
-				set.Uint64(flags.InteropNumValidatorsFlag.Name, 0, "")
-				assert.NoError(t, set.Set(flags.InteropNumValidatorsFlag.Name, "20"))
-				return cli.NewContext(&app, set, nil)
-			},
-			"interop",
-		},
-		{
-			"genesis time set",
-			func() *cli.Context {
-				app := cli.App{}
-				set := flag.NewFlagSet("test", 0)
-				set.Uint64(flags.InteropGenesisTimeFlag.Name, 0, "")
-				assert.NoError(t, set.Set(flags.InteropGenesisTimeFlag.Name, "200"))
-				return cli.NewContext(&app, set, nil)
-			},
-			"interop",
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			require.NoError(t, configureInteropConfig(tt.flagSetter()))
-			assert.DeepEqual(t, tt.configName, params.BeaconConfig().ConfigName)
-		})
-	}
-}
-
 func TestAliasFlag(t *testing.T) {
 	// Create a new app with the flag
 	app := &cli.App{

beacon-chain/node/node.go

@@ -30,7 +30,6 @@ import (
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/db/filesystem"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/db/kv"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/db/slasherkv"
-	interopcoldstart "github.com/prysmaticlabs/prysm/v5/beacon-chain/deterministic-genesis"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/execution"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/forkchoice"
 	doublylinkedtree "github.com/prysmaticlabs/prysm/v5/beacon-chain/forkchoice/doubly-linked-tree"
@@ -261,10 +260,6 @@ func configureBeacon(cliCtx *cli.Context) error {
 
 	configureNetwork(cliCtx)
 
-	if err := configureInteropConfig(cliCtx); err != nil {
-		return errors.Wrap(err, "could not configure interop config")
-	}
-
 	if err := configureExecutionSetting(cliCtx); err != nil {
 		return errors.Wrap(err, "could not configure execution setting")
 	}
@@ -324,11 +319,6 @@ func registerServices(cliCtx *cli.Context, beacon *BeaconNode, synchronizer *sta
 		return errors.Wrap(err, "could not register attestation pool service")
 	}
 
-	log.Debugln("Registering Deterministic Genesis Service")
-	if err := beacon.registerDeterministicGenesisService(); err != nil {
-		return errors.Wrap(err, "could not register deterministic genesis service")
-	}
-
 	log.Debugln("Registering Blockchain Service")
 	if err := beacon.registerBlockchainService(beacon.forkChoicer, synchronizer, beacon.initialSyncComplete); err != nil {
 		return errors.Wrap(err, "could not register blockchain service")
@@ -567,6 +557,7 @@ func (b *BeaconNode) startDB(cliCtx *cli.Context, depositAddress string) error {
 	}
 
 	if b.CheckpointInitializer != nil {
+		log.Info("Checkpoint sync - Downloading origin state and block")
 		if err := b.CheckpointInitializer.Initialize(b.ctx, d); err != nil {
 			return err
 		}
@@ -921,20 +912,8 @@ func (b *BeaconNode) registerRPCService(router *http.ServeMux) error {
 		}
 	}
 
-	genesisValidators := b.cliCtx.Uint64(flags.InteropNumValidatorsFlag.Name)
-	var depositFetcher cache.DepositFetcher
-	var chainStartFetcher execution.ChainStartFetcher
-	if genesisValidators > 0 {
-		var interopService *interopcoldstart.Service
-		if err := b.services.FetchService(&interopService); err != nil {
-			return err
-		}
-		depositFetcher = interopService
-		chainStartFetcher = interopService
-	} else {
-		depositFetcher = b.depositCache
-		chainStartFetcher = web3Service
-	}
+	depositFetcher := b.depositCache
+	chainStartFetcher := web3Service
 
 	host := b.cliCtx.String(flags.RPCHost.Name)
 	port := b.cliCtx.String(flags.RPCPort.Name)
@@ -1056,32 +1035,6 @@ func (b *BeaconNode) registerHTTPService(router *http.ServeMux) error {
 	return b.services.RegisterService(g)
 }
 
-func (b *BeaconNode) registerDeterministicGenesisService() error {
-	genesisTime := b.cliCtx.Uint64(flags.InteropGenesisTimeFlag.Name)
-	genesisValidators := b.cliCtx.Uint64(flags.InteropNumValidatorsFlag.Name)
-
-	if genesisValidators > 0 {
-		svc := interopcoldstart.NewService(b.ctx, &interopcoldstart.Config{
-			GenesisTime:   genesisTime,
-			NumValidators: genesisValidators,
-			BeaconDB:      b.db,
-			DepositCache:  b.depositCache,
-		})
-		svc.Start()
-
-		// Register genesis state as start-up state when interop mode.
-		// The start-up state gets reused across services.
-		st, err := b.db.GenesisState(b.ctx)
-		if err != nil {
-			return err
-		}
-		b.finalizedStateAtStartUp = st
-
-		return b.services.RegisterService(svc)
-	}
-	return nil
-}
-
 func (b *BeaconNode) registerValidatorMonitorService(initialSyncComplete chan struct{}) error {
 	cliSlice := b.cliCtx.IntSlice(cmd.ValidatorMonitorIndicesFlag.Name)
 	if cliSlice == nil {

beacon-chain/node/node_test.go

@@ -6,9 +6,7 @@ import (
 	"fmt"
 	"net/http"
 	"net/http/httptest"
-	"os"
 	"path/filepath"
-	"strconv"
 	"testing"
 	"time"
 
@@ -21,13 +19,8 @@ import (
 	mockExecution "github.com/prysmaticlabs/prysm/v5/beacon-chain/execution/testing"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/monitor"
 	"github.com/prysmaticlabs/prysm/v5/cmd"
-	"github.com/prysmaticlabs/prysm/v5/cmd/beacon-chain/flags"
 	"github.com/prysmaticlabs/prysm/v5/config/features"
-	fieldparams "github.com/prysmaticlabs/prysm/v5/config/fieldparams"
-	"github.com/prysmaticlabs/prysm/v5/config/params"
-	ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v5/runtime"
-	"github.com/prysmaticlabs/prysm/v5/runtime/interop"
 	"github.com/prysmaticlabs/prysm/v5/testing/assert"
 	"github.com/prysmaticlabs/prysm/v5/testing/require"
 	logTest "github.com/sirupsen/logrus/hooks/test"
@@ -117,55 +110,6 @@ func TestNodeStart_SyncChecker(t *testing.T) {
 	require.LogsContain(t, hook, "Starting beacon node")
 }
 
-func TestNodeStart_Ok_registerDeterministicGenesisService(t *testing.T) {
-	numValidators := uint64(1)
-	hook := logTest.NewGlobal()
-	app := cli.App{}
-	tmp := fmt.Sprintf("%s/datadirtest2", t.TempDir())
-	set := flag.NewFlagSet("test", 0)
-	set.String("datadir", tmp, "node data directory")
-	set.Uint64(flags.InteropNumValidatorsFlag.Name, numValidators, "")
-	set.String("suggested-fee-recipient", "0x6e35733c5af9B61374A128e6F85f553aF09ff89A", "fee recipient")
-	require.NoError(t, set.Set("suggested-fee-recipient", "0x6e35733c5af9B61374A128e6F85f553aF09ff89A"))
-	genesisState, _, err := interop.GenerateGenesisState(context.Background(), 0, numValidators)
-	require.NoError(t, err, "Could not generate genesis beacon state")
-	for i := uint64(1); i < 2; i++ {
-		var someRoot [32]byte
-		var someKey [fieldparams.BLSPubkeyLength]byte
-		copy(someRoot[:], strconv.Itoa(int(i)))
-		copy(someKey[:], strconv.Itoa(int(i)))
-		genesisState.Validators = append(genesisState.Validators, &ethpb.Validator{
-			PublicKey:                  someKey[:],
-			WithdrawalCredentials:      someRoot[:],
-			EffectiveBalance:           params.BeaconConfig().MaxEffectiveBalance,
-			Slashed:                    false,
-			ActivationEligibilityEpoch: 1,
-			ActivationEpoch:            1,
-			ExitEpoch:                  1,
-			WithdrawableEpoch:          1,
-		})
-		genesisState.Balances = append(genesisState.Balances, params.BeaconConfig().MaxEffectiveBalance)
-	}
-	genesisBytes, err := genesisState.MarshalSSZ()
-	require.NoError(t, err)
-	require.NoError(t, os.WriteFile("genesis_ssz.json", genesisBytes, 0666))
-	set.String("genesis-state", "genesis_ssz.json", "")
-	ctx, cancel := newCliContextWithCancel(&app, set)
-	node, err := New(ctx, cancel, WithBlockchainFlagOptions([]blockchain.Option{}),
-		WithBuilderFlagOptions([]builder.Option{}),
-		WithExecutionChainOptions([]execution.Option{}),
-		WithBlobStorage(filesystem.NewEphemeralBlobStorage(t)))
-	require.NoError(t, err)
-	node.services = &runtime.ServiceRegistry{}
-	go func() {
-		node.Start()
-	}()
-	time.Sleep(3 * time.Second)
-	node.Close()
-	require.LogsContain(t, hook, "Starting beacon node")
-	require.NoError(t, os.Remove("genesis_ssz.json"))
-}
-
 // TestClearDB tests clearing the database
 func TestClearDB(t *testing.T) {
 	hook := logTest.NewGlobal()

beacon-chain/operations/slashings/BUILD.bazel

@@ -25,6 +25,7 @@ go_library(
         "//container/slice:go_default_library",
         "//monitoring/tracing/trace:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
+        "//runtime/version:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
         "@com_github_prometheus_client_golang//prometheus:go_default_library",
         "@com_github_prometheus_client_golang//prometheus/promauto:go_default_library",

beacon-chain/operations/slashings/service.go

@@ -15,6 +15,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v5/container/slice"
 	"github.com/prysmaticlabs/prysm/v5/monitoring/tracing/trace"
 	ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/v5/runtime/version"
 	"github.com/trailofbits/go-mutexasserts"
 )
 
@@ -43,6 +44,11 @@ func (p *Pool) PendingAttesterSlashings(ctx context.Context, state state.ReadOnl
 
 	// Allocate pending slice with a capacity of maxAttesterSlashings or len(p.pendingAttesterSlashing)) depending on the request.
 	maxSlashings := params.BeaconConfig().MaxAttesterSlashings
+
+	// EIP-7549: Beginning from Electra, the max attester slashings is reduced to 1.
+	if state.Version() >= version.Electra {
+		maxSlashings = params.BeaconConfig().MaxAttesterSlashingsElectra
+	}
 	if noLimit {
 		maxSlashings = uint64(len(p.pendingAttesterSlashing))
 	}

beacon-chain/operations/slashings/service_attester_test.go

@@ -516,6 +516,70 @@ func TestPool_PendingAttesterSlashings(t *testing.T) {
 	}
 }
 
+func TestPool_PendingAttesterSlashings_AfterElectra(t *testing.T) {
+	type fields struct {
+		pending []*PendingAttesterSlashing
+		all     bool
+	}
+	params.SetupTestConfigCleanup(t)
+	beaconState, privKeys := util.DeterministicGenesisStateElectra(t, 64)
+
+	pendingSlashings := make([]*PendingAttesterSlashing, 20)
+	slashings := make([]ethpb.AttSlashing, 20)
+	for i := 0; i < len(pendingSlashings); i++ {
+		sl, err := util.GenerateAttesterSlashingForValidator(beaconState, privKeys[i], primitives.ValidatorIndex(i))
+		require.NoError(t, err)
+		pendingSlashings[i] = &PendingAttesterSlashing{
+			attesterSlashing: sl,
+			validatorToSlash: primitives.ValidatorIndex(i),
+		}
+		slashings[i] = sl
+	}
+	tests := []struct {
+		name   string
+		fields fields
+		want   []ethpb.AttSlashing
+	}{
+		{
+			name: "Empty list",
+			fields: fields{
+				pending: []*PendingAttesterSlashing{},
+			},
+			want: []ethpb.AttSlashing{},
+		},
+		{
+			name: "All pending",
+			fields: fields{
+				pending: pendingSlashings,
+				all:     true,
+			},
+			want: slashings,
+		},
+		{
+			name: "All eligible",
+			fields: fields{
+				pending: pendingSlashings,
+			},
+			want: slashings[0:1],
+		},
+		{
+			name: "Multiple indices",
+			fields: fields{
+				pending: pendingSlashings[3:6],
+			},
+			want: slashings[3:4],
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			p := &Pool{
+				pendingAttesterSlashing: tt.fields.pending,
+			}
+			assert.DeepEqual(t, tt.want, p.PendingAttesterSlashings(context.Background(), beaconState, tt.fields.all))
+		})
+	}
+}
+
 func TestPool_PendingAttesterSlashings_Slashed(t *testing.T) {
 	type fields struct {
 		pending []*PendingAttesterSlashing

beacon-chain/p2p/BUILD.bazel

@@ -17,7 +17,6 @@ go_library(
         "handshake.go",
         "info.go",
         "interfaces.go",
-        "iterator.go",
         "log.go",
         "message_id.go",
         "monitoring.go",
@@ -164,12 +163,10 @@ go_test(
         "//proto/eth/v1:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
         "//proto/testing:go_default_library",
-        "//runtime/version:go_default_library",
         "//testing/assert:go_default_library",
         "//testing/require:go_default_library",
         "//testing/util:go_default_library",
         "//time:go_default_library",
-        "//time/slots:go_default_library",
         "@com_github_ethereum_go_ethereum//crypto:go_default_library",
         "@com_github_ethereum_go_ethereum//p2p/discover:go_default_library",
         "@com_github_ethereum_go_ethereum//p2p/enode:go_default_library",

beacon-chain/p2p/broadcaster_test.go

@@ -225,13 +225,6 @@ func TestService_BroadcastAttestationWithDiscoveryAttempts(t *testing.T) {
 	require.NoError(t, err)
 	defer bootListener.Close()
 
-	// Use shorter period for testing.
-	currentPeriod := pollingPeriod
-	pollingPeriod = 1 * time.Second
-	defer func() {
-		pollingPeriod = currentPeriod
-	}()
-
 	bootNode := bootListener.Self()
 	subnet := uint64(5)
 
@@ -240,7 +233,7 @@ func TestService_BroadcastAttestationWithDiscoveryAttempts(t *testing.T) {
 	// setup other nodes.
 	cfg = &Config{
 		Discv5BootStrapAddrs: []string{bootNode.String()},
-		MaxPeers:             30,
+		MaxPeers:             2,
 	}
 	// Setup 2 different hosts
 	for i := 1; i <= 2; i++ {

beacon-chain/p2p/discovery.go

@@ -22,6 +22,7 @@ import (
 	ecdsaprysm "github.com/prysmaticlabs/prysm/v5/crypto/ecdsa"
 	"github.com/prysmaticlabs/prysm/v5/runtime/version"
 	"github.com/prysmaticlabs/prysm/v5/time/slots"
+	"github.com/sirupsen/logrus"
 )
 
 type ListenerRebooter interface {
@@ -47,10 +48,12 @@ const (
 	udp6
 )
 
+const quickProtocolEnrKey = "quic"
+
 type quicProtocol uint16
 
 // quicProtocol is the "quic" key, which holds the QUIC port of the node.
-func (quicProtocol) ENRKey() string { return "quic" }
+func (quicProtocol) ENRKey() string { return quickProtocolEnrKey }
 
 type listenerWrapper struct {
 	mu              sync.RWMutex
@@ -133,68 +136,129 @@ func (l *listenerWrapper) RebootListener() error {
 	return nil
 }
 
-// RefreshENR uses an epoch to refresh the enr entry for our node
-// with the tracked committee ids for the epoch, allowing our node
-// to be dynamically discoverable by others given our tracked committee ids.
-func (s *Service) RefreshENR() {
-	// return early if discv5 isn't running
+// RefreshPersistentSubnets checks that we are tracking our local persistent subnets for a variety of gossip topics.
+// This routine verifies and updates our attestation and sync committee subnets if they have been rotated.
+func (s *Service) RefreshPersistentSubnets() {
+	// Return early if discv5 service isn't running.
 	if s.dv5Listener == nil || !s.isInitialized() {
 		return
 	}
-	currEpoch := slots.ToEpoch(slots.CurrentSlot(uint64(s.genesisTime.Unix())))
-	if err := initializePersistentSubnets(s.dv5Listener.LocalNode().ID(), currEpoch); err != nil {
+
+	// Get the current epoch.
+	currentSlot := slots.CurrentSlot(uint64(s.genesisTime.Unix()))
+	currentEpoch := slots.ToEpoch(currentSlot)
+
+	// Get our node ID.
+	nodeID := s.dv5Listener.LocalNode().ID()
+
+	// Get our node record.
+	record := s.dv5Listener.Self().Record()
+
+	// Get the version of our metadata.
+	metadataVersion := s.Metadata().Version()
+
+	// Initialize persistent subnets.
+	if err := initializePersistentSubnets(nodeID, currentEpoch); err != nil {
 		log.WithError(err).Error("Could not initialize persistent subnets")
 		return
 	}
 
+	// Get the current attestation subnet bitfield.
 	bitV := bitfield.NewBitvector64()
-	committees := cache.SubnetIDs.GetAllSubnets()
-	for _, idx := range committees {
+	attestationCommittees := cache.SubnetIDs.GetAllSubnets()
+	for _, idx := range attestationCommittees {
 		bitV.SetBitAt(idx, true)
 	}
-	currentBitV, err := attBitvector(s.dv5Listener.Self().Record())
+
+	// Get the attestation subnet bitfield we store in our record.
+	inRecordBitV, err := attBitvector(record)
 	if err != nil {
 		log.WithError(err).Error("Could not retrieve att bitfield")
 		return
 	}
 
-	// Compare current epoch with our fork epochs
+	// Get the attestation subnet bitfield in our metadata.
+	inMetadataBitV := s.Metadata().AttnetsBitfield()
+
+	// Is our attestation bitvector record up to date?
+	isBitVUpToDate := bytes.Equal(bitV, inRecordBitV) && bytes.Equal(bitV, inMetadataBitV)
+
+	// Compare current epoch with Altair fork epoch
 	altairForkEpoch := params.BeaconConfig().AltairForkEpoch
-	switch {
-	case currEpoch < altairForkEpoch:
+
+	if currentEpoch < altairForkEpoch {
 		// Phase 0 behaviour.
-		if bytes.Equal(bitV, currentBitV) {
-			// return early if bitfield hasn't changed
+		if isBitVUpToDate {
+			// Return early if bitfield hasn't changed.
 			return
 		}
+
+		// Some data changed. Update the record and the metadata.
 		s.updateSubnetRecordWithMetadata(bitV)
-	default:
-		// Retrieve sync subnets from application level
-		// cache.
-		bitS := bitfield.Bitvector4{byte(0x00)}
-		committees = cache.SyncSubnetIDs.GetAllSubnets(currEpoch)
-		for _, idx := range committees {
-			bitS.SetBitAt(idx, true)
-		}
-		currentBitS, err := syncBitvector(s.dv5Listener.Self().Record())
-		if err != nil {
-			log.WithError(err).Error("Could not retrieve sync bitfield")
-			return
-		}
-		if bytes.Equal(bitV, currentBitV) && bytes.Equal(bitS, currentBitS) &&
-			s.Metadata().Version() == version.Altair {
-			// return early if bitfields haven't changed
-			return
-		}
-		s.updateSubnetRecordWithMetadataV2(bitV, bitS)
+
+		// Ping all peers.
+		s.pingPeersAndLogEnr()
+
+		return
 	}
-	// ping all peers to inform them of new metadata
+
+	// Get the current sync subnet bitfield.
+	bitS := bitfield.Bitvector4{byte(0x00)}
+	syncCommittees := cache.SyncSubnetIDs.GetAllSubnets(currentEpoch)
+	for _, idx := range syncCommittees {
+		bitS.SetBitAt(idx, true)
+	}
+
+	// Get the sync subnet bitfield we store in our record.
+	inRecordBitS, err := syncBitvector(record)
+	if err != nil {
+		log.WithError(err).Error("Could not retrieve sync bitfield")
+		return
+	}
+
+	// Get the sync subnet bitfield in our metadata.
+	currentBitSInMetadata := s.Metadata().SyncnetsBitfield()
+
+	// Is our sync bitvector record up to date?
+	isBitSUpToDate := bytes.Equal(bitS, inRecordBitS) && bytes.Equal(bitS, currentBitSInMetadata)
+
+	if metadataVersion == version.Altair && isBitVUpToDate && isBitSUpToDate {
+		// Nothing to do, return early.
+		return
+	}
+
+	// Some data have changed, update our record and metadata.
+	s.updateSubnetRecordWithMetadataV2(bitV, bitS)
+
+	// Ping all peers to inform them of new metadata
 	s.pingPeersAndLogEnr()
 }
 
 // listen for new nodes watches for new nodes in the network and adds them to the peerstore.
 func (s *Service) listenForNewNodes() {
-	iterator := filterNodes(s.ctx, s.dv5Listener.RandomNodes(), s.filterPeer)
+	const (
+		minLogInterval = 1 * time.Minute
+		thresholdLimit = 5
+	)
+
+	peersSummary := func(threshold uint) (uint, uint) {
+		// Retrieve how many active peers we have.
+		activePeers := s.Peers().Active()
+		activePeerCount := uint(len(activePeers))
+
+		// Compute how many peers we are missing to reach the threshold.
+		if activePeerCount >= threshold {
+			return activePeerCount, 0
+		}
+
+		missingPeerCount := threshold - activePeerCount
+
+		return activePeerCount, missingPeerCount
+	}
+
+	var lastLogTime time.Time
+
+	iterator := s.dv5Listener.RandomNodes()
 	defer iterator.Close()
 	connectivityTicker := time.NewTicker(1 * time.Minute)
 	thresholdCount := 0
@@ -203,25 +267,31 @@ func (s *Service) listenForNewNodes() {
 		select {
 		case <-s.ctx.Done():
 			return
+
 		case <-connectivityTicker.C:
 			// Skip the connectivity check if not enabled.
 			if !features.Get().EnableDiscoveryReboot {
 				continue
 			}
+
 			if !s.isBelowOutboundPeerThreshold() {
 				// Reset counter if we are beyond the threshold
 				thresholdCount = 0
 				continue
 			}
+
 			thresholdCount++
+
 			// Reboot listener if connectivity drops
-			if thresholdCount > 5 {
-				log.WithField("outboundConnectionCount", len(s.peers.OutboundConnected())).Warn("Rebooting discovery listener, reached threshold.")
+			if thresholdCount > thresholdLimit {
+				outBoundConnectedCount := len(s.peers.OutboundConnected())
+				log.WithField("outboundConnectionCount", outBoundConnectedCount).Warn("Rebooting discovery listener, reached threshold.")
 				if err := s.dv5Listener.RebootListener(); err != nil {
 					log.WithError(err).Error("Could not reboot listener")
 					continue
 				}
-				iterator = filterNodes(s.ctx, s.dv5Listener.RandomNodes(), s.filterPeer)
+
+				iterator = s.dv5Listener.RandomNodes()
 				thresholdCount = 0
 			}
 		default:
@@ -232,17 +302,35 @@ func (s *Service) listenForNewNodes() {
 				time.Sleep(pollingPeriod)
 				continue
 			}
-			wantedCount := s.wantedPeerDials()
-			if wantedCount == 0 {
+
+			// Compute the number of new peers we want to dial.
+			activePeerCount, missingPeerCount := peersSummary(s.cfg.MaxPeers)
+
+			fields := logrus.Fields{
+				"currentPeerCount": activePeerCount,
+				"targetPeerCount":  s.cfg.MaxPeers,
+			}
+
+			if missingPeerCount == 0 {
 				log.Trace("Not looking for peers, at peer limit")
 				time.Sleep(pollingPeriod)
 				continue
 			}
+
+			if time.Since(lastLogTime) > minLogInterval {
+				lastLogTime = time.Now()
+				log.WithFields(fields).Debug("Searching for new active peers")
+			}
+
 			// Restrict dials if limit is applied.
 			if flags.MaxDialIsActive() {
-				wantedCount = min(wantedCount, flags.Get().MaxConcurrentDials)
+				maxConcurrentDials := uint(flags.Get().MaxConcurrentDials)
+				missingPeerCount = min(missingPeerCount, maxConcurrentDials)
 			}
-			wantedNodes := enode.ReadNodes(iterator, wantedCount)
+
+			// Search for new peers.
+			wantedNodes := searchForPeers(iterator, batchPeriod, missingPeerCount, s.filterPeer)
+
 			wg := new(sync.WaitGroup)
 			for i := 0; i < len(wantedNodes); i++ {
 				node := wantedNodes[i]
@@ -458,6 +546,8 @@ func (s *Service) filterPeer(node *enode.Node) bool {
 
 	// Ignore nodes that are already active.
 	if s.peers.IsActive(peerData.ID) {
+		// Constantly update enr for known peers
+		s.peers.UpdateENR(node.Record(), peerData.ID)
 		return false
 	}
 
@@ -526,17 +616,6 @@ func (s *Service) isBelowOutboundPeerThreshold() bool {
 	return outBoundCount < outBoundThreshold
 }
 
-func (s *Service) wantedPeerDials() int {
-	maxPeers := int(s.cfg.MaxPeers)
-
-	activePeers := len(s.Peers().Active())
-	wantedCount := 0
-	if maxPeers > activePeers {
-		wantedCount = maxPeers - activePeers
-	}
-	return wantedCount
-}
-
 // PeersFromStringAddrs converts peer raw ENRs into multiaddrs for p2p.
 func PeersFromStringAddrs(addrs []string) ([]ma.Multiaddr, error) {
 	var allAddrs []ma.Multiaddr

beacon-chain/p2p/discovery_test.go

@@ -16,6 +16,8 @@ import (
 	"github.com/ethereum/go-ethereum/p2p/discover"
 	"github.com/ethereum/go-ethereum/p2p/enode"
 	"github.com/ethereum/go-ethereum/p2p/enr"
+	"github.com/libp2p/go-libp2p"
+	"github.com/libp2p/go-libp2p/core/crypto"
 	"github.com/libp2p/go-libp2p/core/host"
 	"github.com/libp2p/go-libp2p/core/network"
 	"github.com/libp2p/go-libp2p/core/peer"
@@ -30,13 +32,12 @@ import (
 	"github.com/prysmaticlabs/prysm/v5/config/params"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/wrapper"
 	leakybucket "github.com/prysmaticlabs/prysm/v5/container/leaky-bucket"
+	ecdsaprysm "github.com/prysmaticlabs/prysm/v5/crypto/ecdsa"
 	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
 	prysmNetwork "github.com/prysmaticlabs/prysm/v5/network"
 	ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/v5/runtime/version"
 	"github.com/prysmaticlabs/prysm/v5/testing/assert"
 	"github.com/prysmaticlabs/prysm/v5/testing/require"
-	"github.com/prysmaticlabs/prysm/v5/time/slots"
 	logTest "github.com/sirupsen/logrus/hooks/test"
 )
 
@@ -131,6 +132,10 @@ func TestStartDiscV5_DiscoverAllPeers(t *testing.T) {
 }
 
 func TestCreateLocalNode(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
+	cfg := params.BeaconConfig()
+	cfg.Eip7594ForkEpoch = 1
+	params.OverrideBeaconConfig(cfg)
 	testCases := []struct {
 		name          string
 		cfg           *Config
@@ -499,192 +504,270 @@ func addPeer(t *testing.T, p *peers.Status, state peerdata.ConnectionState, outb
 	return id
 }
 
-func TestRefreshENR_ForkBoundaries(t *testing.T) {
+func createAndConnectPeer(t *testing.T, p2pService *testp2p.TestP2P, offset int) {
+	// Create the private key.
+	privateKeyBytes := make([]byte, 32)
+	for i := 0; i < 32; i++ {
+		privateKeyBytes[i] = byte(offset + i)
+	}
+
+	privateKey, err := crypto.UnmarshalSecp256k1PrivateKey(privateKeyBytes)
+	require.NoError(t, err)
+
+	// Create the peer.
+	peer := testp2p.NewTestP2P(t, libp2p.Identity(privateKey))
+
+	// Add the peer and connect it.
+	p2pService.Peers().Add(&enr.Record{}, peer.PeerID(), nil, network.DirOutbound)
+	p2pService.Peers().SetConnectionState(peer.PeerID(), peers.Connected)
+	p2pService.Connect(peer)
+}
+
+// Define the ping count.
+var actualPingCount int
+
+type check struct {
+	pingCount              int
+	metadataSequenceNumber uint64
+	attestationSubnets     []uint64
+	syncSubnets            []uint64
+	custodySubnetCount     *uint64
+}
+
+func checkPingCountCacheMetadataRecord(
+	t *testing.T,
+	service *Service,
+	expected check,
+) {
+	// Check the ping count.
+	require.Equal(t, expected.pingCount, actualPingCount)
+
+	// Check the attestation subnets in the cache.
+	actualAttestationSubnets := cache.SubnetIDs.GetAllSubnets()
+	require.DeepSSZEqual(t, expected.attestationSubnets, actualAttestationSubnets)
+
+	// Check the metadata sequence number.
+	actualMetadataSequenceNumber := service.metaData.SequenceNumber()
+	require.Equal(t, expected.metadataSequenceNumber, actualMetadataSequenceNumber)
+
+	// Compute expected attestation subnets bits.
+	expectedBitV := bitfield.NewBitvector64()
+	exists := false
+
+	for _, idx := range expected.attestationSubnets {
+		exists = true
+		expectedBitV.SetBitAt(idx, true)
+	}
+
+	// Check attnets in ENR.
+	var actualBitVENR bitfield.Bitvector64
+	err := service.dv5Listener.LocalNode().Node().Record().Load(enr.WithEntry(attSubnetEnrKey, &actualBitVENR))
+	require.NoError(t, err)
+	require.DeepSSZEqual(t, expectedBitV, actualBitVENR)
+
+	// Check attnets in metadata.
+	if !exists {
+		expectedBitV = nil
+	}
+
+	actualBitVMetadata := service.metaData.AttnetsBitfield()
+	require.DeepSSZEqual(t, expectedBitV, actualBitVMetadata)
+
+	if expected.syncSubnets != nil {
+		// Compute expected sync subnets bits.
+		expectedBitS := bitfield.NewBitvector4()
+		exists = false
+
+		for _, idx := range expected.syncSubnets {
+			exists = true
+			expectedBitS.SetBitAt(idx, true)
+		}
+
+		// Check syncnets in ENR.
+		var actualBitSENR bitfield.Bitvector4
+		err := service.dv5Listener.LocalNode().Node().Record().Load(enr.WithEntry(syncCommsSubnetEnrKey, &actualBitSENR))
+		require.NoError(t, err)
+		require.DeepSSZEqual(t, expectedBitS, actualBitSENR)
+
+		// Check syncnets in metadata.
+		if !exists {
+			expectedBitS = nil
+		}
+
+		actualBitSMetadata := service.metaData.SyncnetsBitfield()
+		require.DeepSSZEqual(t, expectedBitS, actualBitSMetadata)
+	}
+}
+
+func TestRefreshPersistentSubnets(t *testing.T) {
 	params.SetupTestConfigCleanup(t)
+
 	// Clean up caches after usage.
 	defer cache.SubnetIDs.EmptyAllCaches()
+	defer cache.SyncSubnetIDs.EmptyAllCaches()
 
-	tests := []struct {
-		name           string
-		svcBuilder     func(t *testing.T) *Service
-		postValidation func(t *testing.T, s *Service)
+	const (
+		altairForkEpoch  = 5
+		eip7594ForkEpoch = 10
+	)
+
+	// Set up epochs.
+	defaultCfg := params.BeaconConfig()
+	cfg := defaultCfg.Copy()
+	cfg.AltairForkEpoch = altairForkEpoch
+	cfg.Eip7594ForkEpoch = eip7594ForkEpoch
+	params.OverrideBeaconConfig(cfg)
+
+	// Compute the number of seconds per epoch.
+	secondsPerSlot := params.BeaconConfig().SecondsPerSlot
+	slotsPerEpoch := params.BeaconConfig().SlotsPerEpoch
+	secondsPerEpoch := secondsPerSlot * uint64(slotsPerEpoch)
+
+	testCases := []struct {
+		name              string
+		epochSinceGenesis uint64
+		checks            []check
 	}{
 		{
-			name: "metadata no change",
-			svcBuilder: func(t *testing.T) *Service {
-				port := 2000
-				ipAddr, pkey := createAddrAndPrivKey(t)
-				s := &Service{
-					genesisTime:           time.Now(),
-					genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
-					cfg:                   &Config{UDPPort: uint(port)},
-				}
-				createListener := func() (*discover.UDPv5, error) {
-					return s.createListener(ipAddr, pkey)
-				}
-				listener, err := newListener(createListener)
-				assert.NoError(t, err)
-				s.dv5Listener = listener
-				s.metaData = wrapper.WrappedMetadataV0(new(ethpb.MetaDataV0))
-				s.updateSubnetRecordWithMetadata([]byte{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00})
-				return s
-			},
-			postValidation: func(t *testing.T, s *Service) {
-				currEpoch := slots.ToEpoch(slots.CurrentSlot(uint64(s.genesisTime.Unix())))
-				subs, err := computeSubscribedSubnets(s.dv5Listener.LocalNode().ID(), currEpoch)
-				assert.NoError(t, err)
-
-				bitV := bitfield.NewBitvector64()
-				for _, idx := range subs {
-					bitV.SetBitAt(idx, true)
-				}
-				assert.DeepEqual(t, bitV, s.metaData.AttnetsBitfield())
+			name:              "Phase0",
+			epochSinceGenesis: 0,
+			checks: []check{
+				{
+					pingCount:              0,
+					metadataSequenceNumber: 0,
+					attestationSubnets:     []uint64{},
+				},
+				{
+					pingCount:              1,
+					metadataSequenceNumber: 1,
+					attestationSubnets:     []uint64{40, 41},
+				},
+				{
+					pingCount:              1,
+					metadataSequenceNumber: 1,
+					attestationSubnets:     []uint64{40, 41},
+				},
+				{
+					pingCount:              1,
+					metadataSequenceNumber: 1,
+					attestationSubnets:     []uint64{40, 41},
+				},
 			},
 		},
 		{
-			name: "metadata updated",
-			svcBuilder: func(t *testing.T) *Service {
-				port := 2000
-				ipAddr, pkey := createAddrAndPrivKey(t)
-				s := &Service{
-					genesisTime:           time.Now(),
-					genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
-					cfg:                   &Config{UDPPort: uint(port)},
-				}
-				createListener := func() (*discover.UDPv5, error) {
-					return s.createListener(ipAddr, pkey)
-				}
-				listener, err := newListener(createListener)
-				assert.NoError(t, err)
-				s.dv5Listener = listener
-				s.metaData = wrapper.WrappedMetadataV0(new(ethpb.MetaDataV0))
-				s.updateSubnetRecordWithMetadata([]byte{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01})
-				cache.SubnetIDs.AddPersistentCommittee([]uint64{1, 2, 3, 23}, 0)
-				return s
-			},
-			postValidation: func(t *testing.T, s *Service) {
-				assert.DeepEqual(t, bitfield.Bitvector64{0xe, 0x0, 0x80, 0x0, 0x0, 0x0, 0x0, 0x0}, s.metaData.AttnetsBitfield())
-			},
-		},
-		{
-			name: "metadata updated at fork epoch",
-			svcBuilder: func(t *testing.T) *Service {
-				port := 2000
-				ipAddr, pkey := createAddrAndPrivKey(t)
-				s := &Service{
-					genesisTime:           time.Now().Add(-5 * oneEpochDuration()),
-					genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
-					cfg:                   &Config{UDPPort: uint(port)},
-				}
-				createListener := func() (*discover.UDPv5, error) {
-					return s.createListener(ipAddr, pkey)
-				}
-				listener, err := newListener(createListener)
-				assert.NoError(t, err)
-
-				// Update params
-				cfg := params.BeaconConfig().Copy()
-				cfg.AltairForkEpoch = 5
-				params.OverrideBeaconConfig(cfg)
-				params.BeaconConfig().InitializeForkSchedule()
-
-				s.dv5Listener = listener
-				s.metaData = wrapper.WrappedMetadataV0(new(ethpb.MetaDataV0))
-				s.updateSubnetRecordWithMetadata([]byte{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01})
-				cache.SubnetIDs.AddPersistentCommittee([]uint64{1, 2, 3, 23}, 0)
-				return s
-			},
-			postValidation: func(t *testing.T, s *Service) {
-				assert.Equal(t, version.Altair, s.metaData.Version())
-				assert.DeepEqual(t, bitfield.Bitvector4{0x00}, s.metaData.MetadataObjV1().Syncnets)
-				assert.DeepEqual(t, bitfield.Bitvector64{0xe, 0x0, 0x80, 0x0, 0x0, 0x0, 0x0, 0x0}, s.metaData.AttnetsBitfield())
-			},
-		},
-		{
-			name: "metadata updated at fork epoch with no bitfield",
-			svcBuilder: func(t *testing.T) *Service {
-				port := 2000
-				ipAddr, pkey := createAddrAndPrivKey(t)
-				s := &Service{
-					genesisTime:           time.Now().Add(-5 * oneEpochDuration()),
-					genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
-					cfg:                   &Config{UDPPort: uint(port)},
-				}
-				createListener := func() (*discover.UDPv5, error) {
-					return s.createListener(ipAddr, pkey)
-				}
-				listener, err := newListener(createListener)
-				assert.NoError(t, err)
-
-				// Update params
-				cfg := params.BeaconConfig().Copy()
-				cfg.AltairForkEpoch = 5
-				params.OverrideBeaconConfig(cfg)
-				params.BeaconConfig().InitializeForkSchedule()
-
-				s.dv5Listener = listener
-				s.metaData = wrapper.WrappedMetadataV0(new(ethpb.MetaDataV0))
-				s.updateSubnetRecordWithMetadata([]byte{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00})
-				return s
-			},
-			postValidation: func(t *testing.T, s *Service) {
-				assert.Equal(t, version.Altair, s.metaData.Version())
-				assert.DeepEqual(t, bitfield.Bitvector4{0x00}, s.metaData.MetadataObjV1().Syncnets)
-				currEpoch := slots.ToEpoch(slots.CurrentSlot(uint64(s.genesisTime.Unix())))
-				subs, err := computeSubscribedSubnets(s.dv5Listener.LocalNode().ID(), currEpoch)
-				assert.NoError(t, err)
-
-				bitV := bitfield.NewBitvector64()
-				for _, idx := range subs {
-					bitV.SetBitAt(idx, true)
-				}
-				assert.DeepEqual(t, bitV, s.metaData.AttnetsBitfield())
-			},
-		},
-		{
-			name: "metadata updated past fork epoch with bitfields",
-			svcBuilder: func(t *testing.T) *Service {
-				port := 2000
-				ipAddr, pkey := createAddrAndPrivKey(t)
-				s := &Service{
-					genesisTime:           time.Now().Add(-6 * oneEpochDuration()),
-					genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
-					cfg:                   &Config{UDPPort: uint(port)},
-				}
-				createListener := func() (*discover.UDPv5, error) {
-					return s.createListener(ipAddr, pkey)
-				}
-				listener, err := newListener(createListener)
-				assert.NoError(t, err)
-
-				// Update params
-				cfg := params.BeaconConfig().Copy()
-				cfg.AltairForkEpoch = 5
-				params.OverrideBeaconConfig(cfg)
-				params.BeaconConfig().InitializeForkSchedule()
-
-				s.dv5Listener = listener
-				s.metaData = wrapper.WrappedMetadataV0(new(ethpb.MetaDataV0))
-				s.updateSubnetRecordWithMetadata([]byte{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00})
-				cache.SubnetIDs.AddPersistentCommittee([]uint64{1, 2, 3, 23}, 0)
-				cache.SyncSubnetIDs.AddSyncCommitteeSubnets([]byte{'A'}, 0, []uint64{0, 1}, 0)
-				return s
-			},
-			postValidation: func(t *testing.T, s *Service) {
-				assert.Equal(t, version.Altair, s.metaData.Version())
-				assert.DeepEqual(t, bitfield.Bitvector4{0x03}, s.metaData.MetadataObjV1().Syncnets)
-				assert.DeepEqual(t, bitfield.Bitvector64{0xe, 0x0, 0x80, 0x0, 0x0, 0x0, 0x0, 0x0}, s.metaData.AttnetsBitfield())
+			name:              "Altair",
+			epochSinceGenesis: altairForkEpoch,
+			checks: []check{
+				{
+					pingCount:              0,
+					metadataSequenceNumber: 0,
+					attestationSubnets:     []uint64{},
+					syncSubnets:            nil,
+				},
+				{
+					pingCount:              1,
+					metadataSequenceNumber: 1,
+					attestationSubnets:     []uint64{40, 41},
+					syncSubnets:            nil,
+				},
+				{
+					pingCount:              2,
+					metadataSequenceNumber: 2,
+					attestationSubnets:     []uint64{40, 41},
+					syncSubnets:            []uint64{1, 2},
+				},
+				{
+					pingCount:              2,
+					metadataSequenceNumber: 2,
+					attestationSubnets:     []uint64{40, 41},
+					syncSubnets:            []uint64{1, 2},
+				},
 			},
 		},
 	}
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			s := tt.svcBuilder(t)
-			s.RefreshENR()
-			tt.postValidation(t, s)
-			s.dv5Listener.Close()
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			const peerOffset = 1
+
+			// Initialize the ping count.
+			actualPingCount = 0
+
+			// Create the private key.
+			privateKeyBytes := make([]byte, 32)
+			for i := 0; i < 32; i++ {
+				privateKeyBytes[i] = byte(i)
+			}
+
+			unmarshalledPrivateKey, err := crypto.UnmarshalSecp256k1PrivateKey(privateKeyBytes)
+			require.NoError(t, err)
+
+			privateKey, err := ecdsaprysm.ConvertFromInterfacePrivKey(unmarshalledPrivateKey)
+			require.NoError(t, err)
+
+			// Create a p2p service.
+			p2p := testp2p.NewTestP2P(t)
+
+			// Create and connect a peer.
+			createAndConnectPeer(t, p2p, peerOffset)
+
+			// Create a service.
+			service := &Service{
+				pingMethod: func(_ context.Context, _ peer.ID) error {
+					actualPingCount++
+					return nil
+				},
+				cfg:                   &Config{UDPPort: 2000},
+				peers:                 p2p.Peers(),
+				genesisTime:           time.Now().Add(-time.Duration(tc.epochSinceGenesis*secondsPerEpoch) * time.Second),
+				genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
+			}
+
+			// Set the listener and the metadata.
+			createListener := func() (*discover.UDPv5, error) {
+				return service.createListener(nil, privateKey)
+			}
+
+			listener, err := newListener(createListener)
+			require.NoError(t, err)
+
+			service.dv5Listener = listener
+			service.metaData = wrapper.WrappedMetadataV0(new(ethpb.MetaDataV0))
+
+			// Run a check.
+			checkPingCountCacheMetadataRecord(t, service, tc.checks[0])
+
+			// Refresh the persistent subnets.
+			service.RefreshPersistentSubnets()
+			time.Sleep(10 * time.Millisecond)
+
+			// Run a check.
+			checkPingCountCacheMetadataRecord(t, service, tc.checks[1])
+
+			// Add a sync committee subnet.
+			cache.SyncSubnetIDs.AddSyncCommitteeSubnets([]byte{'a'}, altairForkEpoch, []uint64{1, 2}, 1*time.Hour)
+
+			// Refresh the persistent subnets.
+			service.RefreshPersistentSubnets()
+			time.Sleep(10 * time.Millisecond)
+
+			// Run a check.
+			checkPingCountCacheMetadataRecord(t, service, tc.checks[2])
+
+			// Refresh the persistent subnets.
+			service.RefreshPersistentSubnets()
+			time.Sleep(10 * time.Millisecond)
+
+			// Run a check.
+			checkPingCountCacheMetadataRecord(t, service, tc.checks[3])
+
+			// Clean the test.
+			service.dv5Listener.Close()
 			cache.SubnetIDs.EmptyAllCaches()
 			cache.SyncSubnetIDs.EmptyAllCaches()
 		})
 	}
+
+	// Reset the config.
+	params.OverrideBeaconConfig(defaultCfg)
 }

beacon-chain/p2p/interfaces.go

@@ -82,7 +82,7 @@ type PeerManager interface {
 	Host() host.Host
 	ENR() *enr.Record
 	DiscoveryAddresses() ([]multiaddr.Multiaddr, error)
-	RefreshENR()
+	RefreshPersistentSubnets()
 	FindPeersWithSubnet(ctx context.Context, topic string, subIndex uint64, threshold int) (bool, error)
 	AddPingMethod(reqFunc func(ctx context.Context, id peer.ID) error)
 }

beacon-chain/p2p/iterator.go

@@ -1,36 +0,0 @@
-package p2p
-
-import (
-	"context"
-
-	"github.com/ethereum/go-ethereum/p2p/enode"
-)
-
-// filterNodes wraps an iterator such that Next only returns nodes for which
-// the 'check' function returns true. This custom implementation also
-// checks for context deadlines so that in the event the parent context has
-// expired, we do exit from the search rather than  perform more network
-// lookups for additional peers.
-func filterNodes(ctx context.Context, it enode.Iterator, check func(*enode.Node) bool) enode.Iterator {
-	return &filterIter{ctx, it, check}
-}
-
-type filterIter struct {
-	context.Context
-	enode.Iterator
-	check func(*enode.Node) bool
-}
-
-// Next looks up for the next valid node according to our
-// filter criteria.
-func (f *filterIter) Next() bool {
-	for f.Iterator.Next() {
-		if f.Context.Err() != nil {
-			return false
-		}
-		if f.check(f.Node()) {
-			return true
-		}
-	}
-	return false
-}

beacon-chain/p2p/peers/status.go

@@ -118,6 +118,15 @@ func NewStatus(ctx context.Context, config *StatusConfig) *Status {
 	}
 }
 
+func (p *Status) UpdateENR(record *enr.Record, pid peer.ID) {
+	p.store.Lock()
+	defer p.store.Unlock()
+
+	if peerData, ok := p.store.PeerData(pid); ok {
+		peerData.Enr = record
+	}
+}
+
 // Scorers exposes peer scoring management service.
 func (p *Status) Scorers() *scorers.Service {
 	return p.scorers

beacon-chain/p2p/pubsub_filter.go

@@ -10,15 +10,25 @@ import (
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/p2p/encoder"
 	"github.com/prysmaticlabs/prysm/v5/config/params"
 	"github.com/prysmaticlabs/prysm/v5/network/forks"
+	"github.com/sirupsen/logrus"
 )
 
 var _ pubsub.SubscriptionFilter = (*Service)(nil)
 
 // It is set at this limit to handle the possibility
 // of double topic subscriptions at fork boundaries.
-// -> 64 Attestation Subnets * 2.
-// -> 4 Sync Committee Subnets * 2.
-// -> Block,Aggregate,ProposerSlashing,AttesterSlashing,Exits,SyncContribution * 2.
+// -> BeaconBlock              * 2 = 2
+// -> BeaconAggregateAndProof  * 2 = 2
+// -> VoluntaryExit            * 2 = 2
+// -> ProposerSlashing         * 2 = 2
+// -> AttesterSlashing         * 2 = 2
+// -> 64 Beacon Attestation    * 2 = 128
+// -> SyncContributionAndProof * 2 = 2
+// -> 4 SyncCommitteeSubnets   * 2 = 8
+// -> BlsToExecutionChange     * 2 = 2
+// -> 6 BlobSidecar            * 2 = 12
+// -------------------------------------
+// TOTAL                           = 162
 const pubsubSubscriptionRequestLimit = 200
 
 // CanSubscribe returns true if the topic is of interest and we could subscribe to it.
@@ -95,8 +105,15 @@ func (s *Service) CanSubscribe(topic string) bool {
 // FilterIncomingSubscriptions is invoked for all RPCs containing subscription notifications.
 // This method returns only the topics of interest and may return an error if the subscription
 // request contains too many topics.
-func (s *Service) FilterIncomingSubscriptions(_ peer.ID, subs []*pubsubpb.RPC_SubOpts) ([]*pubsubpb.RPC_SubOpts, error) {
+func (s *Service) FilterIncomingSubscriptions(peerID peer.ID, subs []*pubsubpb.RPC_SubOpts) ([]*pubsubpb.RPC_SubOpts, error) {
 	if len(subs) > pubsubSubscriptionRequestLimit {
+		subsCount := len(subs)
+		log.WithFields(logrus.Fields{
+			"peerID":             peerID,
+			"subscriptionCounts": subsCount,
+			"subscriptionLimit":  pubsubSubscriptionRequestLimit,
+		}).Debug("Too many incoming subscriptions, filtering them")
+
 		return nil, pubsub.ErrTooManySubscriptions
 	}
 

beacon-chain/p2p/service.go

@@ -43,6 +43,10 @@ var _ runtime.Service = (*Service)(nil)
 // defined below.
 var pollingPeriod = 6 * time.Second
 
+// When looking for new nodes, if not enough nodes are found,
+// we stop after this spent time.
+var batchPeriod = 2 * time.Second
+
 // Refresh rate of ENR set at twice per slot.
 var refreshRate = slots.DivideSlotBy(2)
 
@@ -227,7 +231,7 @@ func (s *Service) Start() {
 	}
 	// Initialize metadata according to the
 	// current epoch.
-	s.RefreshENR()
+	s.RefreshPersistentSubnets()
 
 	// Periodic functions.
 	async.RunEvery(s.ctx, params.BeaconConfig().TtfbTimeoutDuration(), func() {
@@ -235,7 +239,7 @@ func (s *Service) Start() {
 	})
 	async.RunEvery(s.ctx, 30*time.Minute, s.Peers().Prune)
 	async.RunEvery(s.ctx, time.Duration(params.BeaconConfig().RespTimeout)*time.Second, s.updateMetrics)
-	async.RunEvery(s.ctx, refreshRate, s.RefreshENR)
+	async.RunEvery(s.ctx, refreshRate, s.RefreshPersistentSubnets)
 	async.RunEvery(s.ctx, 1*time.Minute, func() {
 		inboundQUICCount := len(s.peers.InboundConnectedWithProtocol(peers.QUIC))
 		inboundTCPCount := len(s.peers.InboundConnectedWithProtocol(peers.TCP))

beacon-chain/p2p/subnets.go

@@ -2,6 +2,7 @@ package p2p
 
 import (
 	"context"
+	"math"
 	"strings"
 	"sync"
 	"time"
@@ -19,22 +20,24 @@ import (
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/wrapper"
 	"github.com/prysmaticlabs/prysm/v5/crypto/hash"
 	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
-	mathutil "github.com/prysmaticlabs/prysm/v5/math"
 	"github.com/prysmaticlabs/prysm/v5/monitoring/tracing/trace"
 	pb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
+	"github.com/sirupsen/logrus"
 )
 
-var attestationSubnetCount = params.BeaconConfig().AttestationSubnetCount
-var syncCommsSubnetCount = params.BeaconConfig().SyncCommitteeSubnetCount
+var (
+	attestationSubnetCount = params.BeaconConfig().AttestationSubnetCount
+	syncCommsSubnetCount   = params.BeaconConfig().SyncCommitteeSubnetCount
 
-var attSubnetEnrKey = params.BeaconNetworkConfig().AttSubnetKey
-var syncCommsSubnetEnrKey = params.BeaconNetworkConfig().SyncCommsSubnetKey
+	attSubnetEnrKey       = params.BeaconNetworkConfig().AttSubnetKey
+	syncCommsSubnetEnrKey = params.BeaconNetworkConfig().SyncCommsSubnetKey
+)
 
 // The value used with the subnet, in order
 // to create an appropriate key to retrieve
 // the relevant lock. This is used to differentiate
-// sync subnets from attestation subnets. This is deliberately
-// chosen as more than 64(attestation subnet count).
+// sync subnets from others. This is deliberately
+// chosen as more than 64 (attestation subnet count).
 const syncLockerVal = 100
 
 // The value used with the blob sidecar subnet, in order
@@ -44,6 +47,79 @@ const syncLockerVal = 100
 // chosen more than sync and attestation subnet combined.
 const blobSubnetLockerVal = 110
 
+// nodeFilter return a function that filters nodes based on the subnet topic and subnet index.
+func (s *Service) nodeFilter(topic string, index uint64) (func(node *enode.Node) bool, error) {
+	switch {
+	case strings.Contains(topic, GossipAttestationMessage):
+		return s.filterPeerForAttSubnet(index), nil
+	case strings.Contains(topic, GossipSyncCommitteeMessage):
+		return s.filterPeerForSyncSubnet(index), nil
+	default:
+		return nil, errors.Errorf("no subnet exists for provided topic: %s", topic)
+	}
+}
+
+// searchForPeers performs a network search for peers subscribed to a particular subnet.
+// It exits as soon as one of these conditions is met:
+// - It looped through `batchSize` nodes.
+// - It found `peersToFindCount“ peers corresponding to the `filter` criteria.
+// - Iterator is exhausted.
+func searchForPeers(
+	iterator enode.Iterator,
+	batchPeriod time.Duration,
+	peersToFindCount uint,
+	filter func(node *enode.Node) bool,
+) []*enode.Node {
+	nodeFromNodeID := make(map[enode.ID]*enode.Node)
+	start := time.Now()
+
+	for time.Since(start) < batchPeriod && uint(len(nodeFromNodeID)) < peersToFindCount && iterator.Next() {
+		node := iterator.Node()
+
+		// Filter out nodes that do not meet the criteria.
+		if !filter(node) {
+			continue
+		}
+
+		// Remove duplicates, keeping the node with higher seq.
+		prevNode, ok := nodeFromNodeID[node.ID()]
+		if ok && prevNode.Seq() > node.Seq() {
+			continue
+		}
+
+		nodeFromNodeID[node.ID()] = node
+	}
+
+	// Convert the map to a slice.
+	nodes := make([]*enode.Node, 0, len(nodeFromNodeID))
+	for _, node := range nodeFromNodeID {
+		nodes = append(nodes, node)
+	}
+
+	return nodes
+}
+
+// dialPeer dials a peer in a separate goroutine.
+func (s *Service) dialPeer(ctx context.Context, wg *sync.WaitGroup, node *enode.Node) {
+	info, _, err := convertToAddrInfo(node)
+	if err != nil {
+		return
+	}
+
+	if info == nil {
+		return
+	}
+
+	wg.Add(1)
+	go func() {
+		if err := s.connectWithPeer(ctx, *info); err != nil {
+			log.WithError(err).Tracef("Could not connect with peer %s", info.String())
+		}
+
+		wg.Done()
+	}()
+}
+
 // FindPeersWithSubnet performs a network search for peers
 // subscribed to a particular subnet. Then it tries to connect
 // with those peers. This method will block until either:
@@ -52,67 +128,104 @@ const blobSubnetLockerVal = 110
 // On some edge cases, this method may hang indefinitely while peers
 // are actually found. In such a case, the user should cancel the context
 // and re-run the method again.
-func (s *Service) FindPeersWithSubnet(ctx context.Context, topic string,
-	index uint64, threshold int) (bool, error) {
+func (s *Service) FindPeersWithSubnet(
+	ctx context.Context,
+	topic string,
+	index uint64,
+	threshold int,
+) (bool, error) {
+	const minLogInterval = 1 * time.Minute
+
 	ctx, span := trace.StartSpan(ctx, "p2p.FindPeersWithSubnet")
 	defer span.End()
 
 	span.SetAttributes(trace.Int64Attribute("index", int64(index))) // lint:ignore uintcast -- It's safe to do this for tracing.
 
 	if s.dv5Listener == nil {
-		// return if discovery isn't set
+		// Return if discovery isn't set
 		return false, nil
 	}
 
 	topic += s.Encoding().ProtocolSuffix()
 	iterator := s.dv5Listener.RandomNodes()
 	defer iterator.Close()
-	switch {
-	case strings.Contains(topic, GossipAttestationMessage):
-		iterator = filterNodes(ctx, iterator, s.filterPeerForAttSubnet(index))
-	case strings.Contains(topic, GossipSyncCommitteeMessage):
-		iterator = filterNodes(ctx, iterator, s.filterPeerForSyncSubnet(index))
-	default:
-		return false, errors.New("no subnet exists for provided topic")
+
+	filter, err := s.nodeFilter(topic, index)
+	if err != nil {
+		return false, errors.Wrap(err, "node filter")
 	}
 
+	peersSummary := func(topic string, threshold int) (int, int) {
+		// Retrieve how many peers we have for this topic.
+		peerCountForTopic := len(s.pubsub.ListPeers(topic))
+
+		// Compute how many peers we are missing to reach the threshold.
+		missingPeerCountForTopic := max(0, threshold-peerCountForTopic)
+
+		return peerCountForTopic, missingPeerCountForTopic
+	}
+
+	// Compute how many peers we are missing to reach the threshold.
+	peerCountForTopic, missingPeerCountForTopic := peersSummary(topic, threshold)
+
+	// Exit early if we have enough peers.
+	if missingPeerCountForTopic == 0 {
+		return true, nil
+	}
+
+	log := log.WithFields(logrus.Fields{
+		"topic":           topic,
+		"targetPeerCount": threshold,
+	})
+
+	log.WithField("currentPeerCount", peerCountForTopic).Debug("Searching for new peers for a subnet - start")
+
+	lastLogTime := time.Now()
+
 	wg := new(sync.WaitGroup)
 	for {
-		currNum := len(s.pubsub.ListPeers(topic))
-		if currNum >= threshold {
+		// If the context is done, we can exit the loop. This is the unhappy path.
+		if err := ctx.Err(); err != nil {
+			return false, errors.Errorf(
+				"unable to find requisite number of peers for topic %s - only %d out of %d peers available after searching",
+				topic, peerCountForTopic, threshold,
+			)
+		}
+
+		// Search for new peers in the network.
+		nodes := searchForPeers(iterator, batchPeriod, uint(missingPeerCountForTopic), filter)
+
+		// Restrict dials if limit is applied.
+		maxConcurrentDials := math.MaxInt
+		if flags.MaxDialIsActive() {
+			maxConcurrentDials = flags.Get().MaxConcurrentDials
+		}
+
+		// Dial the peers in batches.
+		for start := 0; start < len(nodes); start += maxConcurrentDials {
+			stop := min(start+maxConcurrentDials, len(nodes))
+			for _, node := range nodes[start:stop] {
+				s.dialPeer(ctx, wg, node)
+			}
+
+			// Wait for all dials to be completed.
+			wg.Wait()
+		}
+
+		peerCountForTopic, missingPeerCountForTopic := peersSummary(topic, threshold)
+
+		// If we have enough peers, we can exit the loop. This is the happy path.
+		if missingPeerCountForTopic == 0 {
 			break
 		}
-		if err := ctx.Err(); err != nil {
-			return false, errors.Errorf("unable to find requisite number of peers for topic %s - "+
-				"only %d out of %d peers were able to be found", topic, currNum, threshold)
-		}
-		nodeCount := int(params.BeaconNetworkConfig().MinimumPeersInSubnetSearch)
-		// Restrict dials if limit is applied.
-		if flags.MaxDialIsActive() {
-			nodeCount = min(nodeCount, flags.Get().MaxConcurrentDials)
-		}
-		nodes := enode.ReadNodes(iterator, nodeCount)
-		for _, node := range nodes {
-			info, _, err := convertToAddrInfo(node)
-			if err != nil {
-				continue
-			}
 
-			if info == nil {
-				continue
-			}
-
-			wg.Add(1)
-			go func() {
-				if err := s.connectWithPeer(ctx, *info); err != nil {
-					log.WithError(err).Tracef("Could not connect with peer %s", info.String())
-				}
-				wg.Done()
-			}()
+		if time.Since(lastLogTime) > minLogInterval {
+			lastLogTime = time.Now()
+			log.WithField("currentPeerCount", peerCountForTopic).Debug("Searching for new peers for a subnet - continue")
 		}
-		// Wait for all dials to be completed.
-		wg.Wait()
 	}
+
+	log.WithField("currentPeerCount", threshold).Debug("Searching for new peers for a subnet - success")
 	return true, nil
 }
 
@@ -156,11 +269,17 @@ func (s *Service) filterPeerForSyncSubnet(index uint64) func(node *enode.Node) b
 // lower threshold to broadcast object compared to searching
 // for a subnet. So that even in the event of poor peer
 // connectivity, we can still broadcast an attestation.
-func (s *Service) hasPeerWithSubnet(topic string) bool {
+func (s *Service) hasPeerWithSubnet(subnetTopic string) bool {
 	// In the event peer threshold is lower, we will choose the lower
 	// threshold.
-	minPeers := mathutil.Min(1, uint64(flags.Get().MinimumPeersPerSubnet))
-	return len(s.pubsub.ListPeers(topic+s.Encoding().ProtocolSuffix())) >= int(minPeers) // lint:ignore uintcast -- Min peers can be safely cast to int.
+	minPeers := min(1, flags.Get().MinimumPeersPerSubnet)
+	topic := subnetTopic + s.Encoding().ProtocolSuffix()
+	peersWithSubnet := s.pubsub.ListPeers(topic)
+	peersWithSubnetCount := len(peersWithSubnet)
+
+	enoughPeers := peersWithSubnetCount >= minPeers
+
+	return enoughPeers
 }
 
 // Updates the service's discv5 listener record's attestation subnet
@@ -355,10 +474,10 @@ func syncBitvector(record *enr.Record) (bitfield.Bitvector4, error) {
 
 // The subnet locker is a map which keeps track of all
 // mutexes stored per subnet. This locker is re-used
-// between both the attestation and sync subnets. In
-// order to differentiate between attestation and sync
-// subnets. Sync subnets are stored by (subnet+syncLockerVal). This
-// is to prevent conflicts while allowing both subnets
+// between both the attestation, sync and blob subnets.
+// Sync subnets are stored by (subnet+syncLockerVal).
+// Blob subnets are stored by (subnet+blobSubnetLockerVal).
+// This is to prevent conflicts while allowing subnets
 // to use a single locker.
 func (s *Service) subnetLocker(i uint64) *sync.RWMutex {
 	s.subnetsLockLock.Lock()

beacon-chain/p2p/testing/BUILD.bazel

@@ -27,6 +27,7 @@ go_library(
         "@com_github_ethereum_go_ethereum//p2p/enode:go_default_library",
         "@com_github_ethereum_go_ethereum//p2p/enr:go_default_library",
         "@com_github_libp2p_go_libp2p//:go_default_library",
+        "@com_github_libp2p_go_libp2p//config:go_default_library",
         "@com_github_libp2p_go_libp2p//core:go_default_library",
         "@com_github_libp2p_go_libp2p//core/connmgr:go_default_library",
         "@com_github_libp2p_go_libp2p//core/control:go_default_library",

beacon-chain/p2p/testing/fuzz_p2p.go

@@ -65,8 +65,8 @@ func (*FakeP2P) FindPeersWithSubnet(_ context.Context, _ string, _ uint64, _ int
 	return false, nil
 }
 
-// RefreshENR mocks the p2p func.
-func (*FakeP2P) RefreshENR() {}
+// RefreshPersistentSubnets mocks the p2p func.
+func (*FakeP2P) RefreshPersistentSubnets() {}
 
 // LeaveTopic -- fake.
 func (*FakeP2P) LeaveTopic(_ string) error {

beacon-chain/p2p/testing/mock_peermanager.go

@@ -47,8 +47,8 @@ func (m *MockPeerManager) DiscoveryAddresses() ([]multiaddr.Multiaddr, error) {
 	return m.DiscoveryAddr, nil
 }
 
-// RefreshENR .
-func (*MockPeerManager) RefreshENR() {}
+// RefreshPersistentSubnets .
+func (*MockPeerManager) RefreshPersistentSubnets() {}
 
 // FindPeersWithSubnet .
 func (*MockPeerManager) FindPeersWithSubnet(_ context.Context, _ string, _ uint64, _ int) (bool, error) {

beacon-chain/p2p/testing/p2p.go

@@ -10,9 +10,11 @@ import (
 	"testing"
 	"time"
 
+	"github.com/ethereum/go-ethereum/p2p/enode"
 	"github.com/ethereum/go-ethereum/p2p/enr"
 	"github.com/libp2p/go-libp2p"
 	pubsub "github.com/libp2p/go-libp2p-pubsub"
+	"github.com/libp2p/go-libp2p/config"
 	core "github.com/libp2p/go-libp2p/core"
 	"github.com/libp2p/go-libp2p/core/control"
 	"github.com/libp2p/go-libp2p/core/host"
@@ -34,13 +36,17 @@ import (
 
 // We have to declare this again here to prevent a circular dependency
 // with the main p2p package.
-const metatadataV1Topic = "/eth2/beacon_chain/req/metadata/1"
-const metatadataV2Topic = "/eth2/beacon_chain/req/metadata/2"
+const (
+	metadataV1Topic = "/eth2/beacon_chain/req/metadata/1"
+	metadataV2Topic = "/eth2/beacon_chain/req/metadata/2"
+	metadataV3Topic = "/eth2/beacon_chain/req/metadata/3"
+)
 
 // TestP2P represents a p2p implementation that can be used for testing.
 type TestP2P struct {
 	t               *testing.T
 	BHost           host.Host
+	EnodeID         enode.ID
 	pubsub          *pubsub.PubSub
 	joinedTopics    map[string]*pubsub.Topic
 	BroadcastCalled atomic.Bool
@@ -51,9 +57,17 @@ type TestP2P struct {
 }
 
 // NewTestP2P initializes a new p2p test service.
-func NewTestP2P(t *testing.T) *TestP2P {
+func NewTestP2P(t *testing.T, userOptions ...config.Option) *TestP2P {
 	ctx := context.Background()
-	h, err := libp2p.New(libp2p.ResourceManager(&network.NullResourceManager{}), libp2p.Transport(tcp.NewTCPTransport), libp2p.DefaultListenAddrs)
+	options := []config.Option{
+		libp2p.ResourceManager(&network.NullResourceManager{}),
+		libp2p.Transport(tcp.NewTCPTransport),
+		libp2p.DefaultListenAddrs,
+	}
+
+	options = append(options, userOptions...)
+
+	h, err := libp2p.New(options...)
 	require.NoError(t, err)
 	ps, err := pubsub.NewFloodSub(ctx, h,
 		pubsub.WithMessageSigning(false),
@@ -270,6 +284,11 @@ func (*TestP2P) ENR() *enr.Record {
 	return new(enr.Record)
 }
 
+// NodeID returns the node id of the local peer.
+func (p *TestP2P) NodeID() enode.ID {
+	return p.EnodeID
+}
+
 // DiscoveryAddresses --
 func (*TestP2P) DiscoveryAddresses() ([]multiaddr.Multiaddr, error) {
 	return nil, nil
@@ -278,7 +297,7 @@ func (*TestP2P) DiscoveryAddresses() ([]multiaddr.Multiaddr, error) {
 // AddConnectionHandler handles the connection with a newly connected peer.
 func (p *TestP2P) AddConnectionHandler(f, _ func(ctx context.Context, id peer.ID) error) {
 	p.BHost.Network().Notify(&network.NotifyBundle{
-		ConnectedF: func(net network.Network, conn network.Conn) {
+		ConnectedF: func(_ network.Network, conn network.Conn) {
 			// Must be handled in a goroutine as this callback cannot be blocking.
 			go func() {
 				p.peers.Add(new(enr.Record), conn.RemotePeer(), conn.RemoteMultiaddr(), conn.Stat().Direction)
@@ -302,7 +321,7 @@ func (p *TestP2P) AddConnectionHandler(f, _ func(ctx context.Context, id peer.ID
 // AddDisconnectionHandler --
 func (p *TestP2P) AddDisconnectionHandler(f func(ctx context.Context, id peer.ID) error) {
 	p.BHost.Network().Notify(&network.NotifyBundle{
-		DisconnectedF: func(net network.Network, conn network.Conn) {
+		DisconnectedF: func(_ network.Network, conn network.Conn) {
 			// Must be handled in a goroutine as this callback cannot be blocking.
 			go func() {
 				p.peers.SetConnectionState(conn.RemotePeer(), peers.Disconnecting)
@@ -317,6 +336,8 @@ func (p *TestP2P) AddDisconnectionHandler(f func(ctx context.Context, id peer.ID
 
 // Send a message to a specific peer.
 func (p *TestP2P) Send(ctx context.Context, msg interface{}, topic string, pid peer.ID) (network.Stream, error) {
+	metadataTopics := map[string]bool{metadataV1Topic: true, metadataV2Topic: true, metadataV3Topic: true}
+
 	t := topic
 	if t == "" {
 		return nil, fmt.Errorf("protocol doesn't exist for proto message: %v", msg)
@@ -326,7 +347,7 @@ func (p *TestP2P) Send(ctx context.Context, msg interface{}, topic string, pid p
 		return nil, err
 	}
 
-	if topic != metatadataV1Topic && topic != metatadataV2Topic {
+	if !metadataTopics[topic] {
 		castedMsg, ok := msg.(ssz.Marshaler)
 		if !ok {
 			p.t.Fatalf("%T doesn't support ssz marshaler", msg)
@@ -367,8 +388,8 @@ func (*TestP2P) FindPeersWithSubnet(_ context.Context, _ string, _ uint64, _ int
 	return false, nil
 }
 
-// RefreshENR mocks the p2p func.
-func (*TestP2P) RefreshENR() {}
+// RefreshPersistentSubnets mocks the p2p func.
+func (*TestP2P) RefreshPersistentSubnets() {}
 
 // ForkDigest mocks the p2p func.
 func (p *TestP2P) ForkDigest() ([4]byte, error) {

beacon-chain/rpc/BUILD.bazel

@@ -5,6 +5,7 @@ go_library(
     srcs = [
         "endpoints.go",
         "log.go",
+        "metrics.go",
         "service.go",
     ],
     importpath = "github.com/prysmaticlabs/prysm/v5/beacon-chain/rpc",

beacon-chain/rpc/endpoints.go

@@ -34,18 +34,48 @@ type endpoint struct {
 	methods    []string
 }
 
+// responseWriter is the wrapper to http Response writer.
+type responseWriter struct {
+	http.ResponseWriter
+	statusCode int
+}
+
+// WriteHeader wraps the WriteHeader method of the underlying http.ResponseWriter to capture the status code.
+// Refer for WriteHeader doc: https://pkg.go.dev/net/http@go1.23.3#ResponseWriter.
+func (w *responseWriter) WriteHeader(statusCode int) {
+	w.statusCode = statusCode
+	w.ResponseWriter.WriteHeader(statusCode)
+}
+
 func (e *endpoint) handlerWithMiddleware() http.HandlerFunc {
 	handler := http.Handler(e.handler)
 	for _, m := range e.middleware {
 		handler = m(handler)
 	}
-	return promhttp.InstrumentHandlerDuration(
+
+	handler = promhttp.InstrumentHandlerDuration(
 		httpRequestLatency.MustCurryWith(prometheus.Labels{"endpoint": e.name}),
 		promhttp.InstrumentHandlerCounter(
 			httpRequestCount.MustCurryWith(prometheus.Labels{"endpoint": e.name}),
 			handler,
 		),
 	)
+
+	return func(w http.ResponseWriter, r *http.Request) {
+		// SSE errors are handled separately to avoid interference with the streaming
+		// mechanism and ensure accurate error tracking.
+		if e.template == "/eth/v1/events" {
+			handler.ServeHTTP(w, r)
+			return
+		}
+
+		rw := &responseWriter{ResponseWriter: w, statusCode: http.StatusOK}
+		handler.ServeHTTP(rw, r)
+
+		if rw.statusCode >= 400 {
+			httpErrorCount.WithLabelValues(r.URL.Path, http.StatusText(rw.statusCode), r.Method).Inc()
+		}
+	}
 }
 
 func (s *Service) endpoints(
@@ -142,9 +172,11 @@ func (s *Service) builderEndpoints(stater lookup.Stater) []endpoint {
 	}
 }
 
-func (*Service) blobEndpoints(blocker lookup.Blocker) []endpoint {
+func (s *Service) blobEndpoints(blocker lookup.Blocker) []endpoint {
 	server := &blob.Server{
-		Blocker: blocker,
+		Blocker:               blocker,
+		OptimisticModeFetcher: s.cfg.OptimisticModeFetcher,
+		FinalizationFetcher:   s.cfg.FinalizationFetcher,
 	}
 
 	const namespace = "blob"
@@ -886,10 +918,11 @@ func (*Service) configEndpoints() []endpoint {
 
 func (s *Service) lightClientEndpoints(blocker lookup.Blocker, stater lookup.Stater) []endpoint {
 	server := &lightclient.Server{
-		Blocker:     blocker,
-		Stater:      stater,
-		HeadFetcher: s.cfg.HeadFetcher,
-		BeaconDB:    s.cfg.BeaconDB,
+		Blocker:          blocker,
+		Stater:           stater,
+		HeadFetcher:      s.cfg.HeadFetcher,
+		ChainInfoFetcher: s.cfg.ChainInfoFetcher,
+		BeaconDB:         s.cfg.BeaconDB,
 	}
 
 	const namespace = "lightclient"

beacon-chain/rpc/eth/beacon/BUILD.bazel

@@ -58,6 +58,7 @@ go_library(
         "//runtime/version:go_default_library",
         "//time/slots:go_default_library",
         "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
+        "@com_github_ethereum_go_ethereum//crypto/kzg4844:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
         "@com_github_prysmaticlabs_fastssz//:go_default_library",
         "@com_github_sirupsen_logrus//:go_default_library",
@@ -118,6 +119,7 @@ go_test(
         "//testing/require:go_default_library",
         "//testing/util:go_default_library",
         "//time/slots:go_default_library",
+        "@com_github_crate_crypto_go_kzg_4844//:go_default_library",
         "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
         "@com_github_prysmaticlabs_go_bitfield//:go_default_library",

beacon-chain/rpc/eth/beacon/handlers.go

@@ -11,6 +11,7 @@ import (
 	"strings"
 
 	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/ethereum/go-ethereum/crypto/kzg4844"
 	"github.com/pkg/errors"
 	ssz "github.com/prysmaticlabs/fastssz"
 	"github.com/prysmaticlabs/prysm/v5/api"
@@ -1032,21 +1033,17 @@ func unmarshalStrict(data []byte, v interface{}) error {
 func (s *Server) validateBroadcast(ctx context.Context, r *http.Request, blk *eth.GenericSignedBeaconBlock) error {
 	switch r.URL.Query().Get(broadcastValidationQueryParam) {
 	case broadcastValidationConsensus:
-		b, err := blocks.NewSignedBeaconBlock(blk.Block)
-		if err != nil {
-			return errors.Wrapf(err, "could not create signed beacon block")
-		}
-		if err = s.validateConsensus(ctx, b); err != nil {
+		if err := s.validateConsensus(ctx, blk); err != nil {
 			return errors.Wrap(err, "consensus validation failed")
 		}
 	case broadcastValidationConsensusAndEquivocation:
+		if err := s.validateConsensus(r.Context(), blk); err != nil {
+			return errors.Wrap(err, "consensus validation failed")
+		}
 		b, err := blocks.NewSignedBeaconBlock(blk.Block)
 		if err != nil {
 			return errors.Wrapf(err, "could not create signed beacon block")
 		}
-		if err = s.validateConsensus(r.Context(), b); err != nil {
-			return errors.Wrap(err, "consensus validation failed")
-		}
 		if err = s.validateEquivocation(b.Block()); err != nil {
 			return errors.Wrap(err, "equivocation validation failed")
 		}
@@ -1056,7 +1053,12 @@ func (s *Server) validateBroadcast(ctx context.Context, r *http.Request, blk *et
 	return nil
 }
 
-func (s *Server) validateConsensus(ctx context.Context, blk interfaces.ReadOnlySignedBeaconBlock) error {
+func (s *Server) validateConsensus(ctx context.Context, b *eth.GenericSignedBeaconBlock) error {
+	blk, err := blocks.NewSignedBeaconBlock(b.Block)
+	if err != nil {
+		return errors.Wrapf(err, "could not create signed beacon block")
+	}
+
 	parentBlockRoot := blk.Block().ParentRoot()
 	parentBlock, err := s.Blocker.Block(ctx, parentBlockRoot[:])
 	if err != nil {
@@ -1076,6 +1078,24 @@ func (s *Server) validateConsensus(ctx context.Context, blk interfaces.ReadOnlyS
 	if err != nil {
 		return errors.Wrap(err, "could not execute state transition")
 	}
+
+	var blobs [][]byte
+	var proofs [][]byte
+	switch {
+	case blk.Version() == version.Electra:
+		blobs = b.GetElectra().Blobs
+		proofs = b.GetElectra().KzgProofs
+	case blk.Version() == version.Deneb:
+		blobs = b.GetDeneb().Blobs
+		proofs = b.GetDeneb().KzgProofs
+	default:
+		return nil
+	}
+
+	if err := s.validateBlobSidecars(blk, blobs, proofs); err != nil {
+		return err
+	}
+
 	return nil
 }
 
@@ -1086,6 +1106,25 @@ func (s *Server) validateEquivocation(blk interfaces.ReadOnlyBeaconBlock) error
 	return nil
 }
 
+func (s *Server) validateBlobSidecars(blk interfaces.SignedBeaconBlock, blobs [][]byte, proofs [][]byte) error {
+	if blk.Version() < version.Deneb {
+		return nil
+	}
+	kzgs, err := blk.Block().Body().BlobKzgCommitments()
+	if err != nil {
+		return errors.Wrap(err, "could not get blob kzg commitments")
+	}
+	if len(blobs) != len(proofs) || len(blobs) != len(kzgs) {
+		return errors.New("number of blobs, proofs, and commitments do not match")
+	}
+	for i, blob := range blobs {
+		if err := kzg4844.VerifyBlobProof(kzg4844.Blob(blob), kzg4844.Commitment(kzgs[i]), kzg4844.Proof(proofs[i])); err != nil {
+			return errors.Wrap(err, "could not verify blob proof")
+		}
+	}
+	return nil
+}
+
 // GetBlockRoot retrieves the root of a block.
 func (s *Server) GetBlockRoot(w http.ResponseWriter, r *http.Request) {
 	ctx, span := trace.StartSpan(r.Context(), "beacon.GetBlockRoot")

beacon-chain/rpc/eth/beacon/handlers_test.go

@@ -12,6 +12,7 @@ import (
 	"testing"
 	"time"
 
+	GoKZG "github.com/crate-crypto/go-kzg-4844"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/pkg/errors"
 	"github.com/prysmaticlabs/go-bitfield"
@@ -33,6 +34,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/interfaces"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v5/crypto/bls"
 	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
 	"github.com/prysmaticlabs/prysm/v5/network/httputil"
 	eth "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
@@ -2922,8 +2924,6 @@ func TestValidateConsensus(t *testing.T) {
 	require.NoError(t, err)
 	block, err := util.GenerateFullBlock(st, privs, util.DefaultBlockGenConfig(), st.Slot())
 	require.NoError(t, err)
-	sbb, err := blocks.NewSignedBeaconBlock(block)
-	require.NoError(t, err)
 	parentRoot, err := parentSbb.Block().HashTreeRoot()
 	require.NoError(t, err)
 	server := &Server{
@@ -2931,7 +2931,11 @@ func TestValidateConsensus(t *testing.T) {
 		Stater:  &testutil.MockStater{StatesByRoot: map[[32]byte]state.BeaconState{bytesutil.ToBytes32(parentBlock.Block.StateRoot): parentState}},
 	}
 
-	require.NoError(t, server.validateConsensus(ctx, sbb))
+	require.NoError(t, server.validateConsensus(ctx, &eth.GenericSignedBeaconBlock{
+		Block: &eth.GenericSignedBeaconBlock_Phase0{
+			Phase0: block,
+		},
+	}))
 }
 
 func TestValidateEquivocation(t *testing.T) {
@@ -4152,3 +4156,24 @@ func TestServer_broadcastBlobSidecars(t *testing.T) {
 	require.NoError(t, server.broadcastSeenBlockSidecars(context.Background(), blk, b.GetDeneb().Blobs, b.GetDeneb().KzgProofs))
 	require.LogsContain(t, hook, "Broadcasted blob sidecar for already seen block")
 }
+
+func Test_validateBlobSidecars(t *testing.T) {
+	blob := util.GetRandBlob(123)
+	commitment := GoKZG.KZGCommitment{180, 218, 156, 194, 59, 20, 10, 189, 186, 254, 132, 93, 7, 127, 104, 172, 238, 240, 237, 70, 83, 89, 1, 152, 99, 0, 165, 65, 143, 62, 20, 215, 230, 14, 205, 95, 28, 245, 54, 25, 160, 16, 178, 31, 232, 207, 38, 85}
+	proof := GoKZG.KZGProof{128, 110, 116, 170, 56, 111, 126, 87, 229, 234, 211, 42, 110, 150, 129, 206, 73, 142, 167, 243, 90, 149, 240, 240, 236, 204, 143, 182, 229, 249, 81, 27, 153, 171, 83, 70, 144, 250, 42, 1, 188, 215, 71, 235, 30, 7, 175, 86}
+	blk := util.NewBeaconBlockDeneb()
+	blk.Block.Body.BlobKzgCommitments = [][]byte{commitment[:]}
+	b, err := blocks.NewSignedBeaconBlock(blk)
+	require.NoError(t, err)
+	s := &Server{}
+	require.NoError(t, s.validateBlobSidecars(b, [][]byte{blob[:]}, [][]byte{proof[:]}))
+
+	require.ErrorContains(t, "number of blobs, proofs, and commitments do not match", s.validateBlobSidecars(b, [][]byte{blob[:]}, [][]byte{}))
+
+	sk, err := bls.RandKey()
+	require.NoError(t, err)
+	blk.Block.Body.BlobKzgCommitments = [][]byte{sk.PublicKey().Marshal()}
+	b, err = blocks.NewSignedBeaconBlock(blk)
+	require.NoError(t, err)
+	require.ErrorContains(t, "could not verify blob proof: can't verify opening proof", s.validateBlobSidecars(b, [][]byte{blob[:]}, [][]byte{proof[:]}))
+}

beacon-chain/rpc/eth/blob/BUILD.bazel

@@ -10,12 +10,14 @@ go_library(
     visibility = ["//visibility:public"],
     deps = [
         "//api/server/structs:go_default_library",
+        "//beacon-chain/blockchain:go_default_library",
         "//beacon-chain/rpc/core:go_default_library",
         "//beacon-chain/rpc/lookup:go_default_library",
         "//config/fieldparams:go_default_library",
         "//consensus-types/blocks:go_default_library",
         "//monitoring/tracing/trace:go_default_library",
         "//network/httputil:go_default_library",
+        "//runtime/version:go_default_library",
         "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
     ],

beacon-chain/rpc/eth/blob/handlers.go

@@ -15,6 +15,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v5/monitoring/tracing/trace"
 	"github.com/prysmaticlabs/prysm/v5/network/httputil"
+	"github.com/prysmaticlabs/prysm/v5/runtime/version"
 )
 
 // Blobs is an HTTP handler for Beacon API getBlobs.
@@ -59,7 +60,30 @@ func (s *Server) Blobs(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	httputil.WriteJson(w, buildSidecarsJsonResponse(verifiedBlobs))
+	blk, err := s.Blocker.Block(ctx, []byte(blockId))
+	if err != nil {
+		httputil.HandleError(w, "Could not fetch block: "+err.Error(), http.StatusInternalServerError)
+		return
+	}
+	blkRoot, err := blk.Block().HashTreeRoot()
+	if err != nil {
+		httputil.HandleError(w, "Could not hash block: "+err.Error(), http.StatusInternalServerError)
+		return
+	}
+	isOptimistic, err := s.OptimisticModeFetcher.IsOptimisticForRoot(ctx, blkRoot)
+	if err != nil {
+		httputil.HandleError(w, "Could not check if block is optimistic: "+err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	data := buildSidecarsJsonResponse(verifiedBlobs)
+	resp := &structs.SidecarsResponse{
+		Version:             version.String(blk.Version()),
+		Data:                data,
+		ExecutionOptimistic: isOptimistic,
+		Finalized:           s.FinalizationFetcher.IsFinalized(ctx, blkRoot),
+	}
+	httputil.WriteJson(w, resp)
 }
 
 // parseIndices filters out invalid and duplicate blob indices
@@ -92,14 +116,14 @@ loop:
 	return indices, nil
 }
 
-func buildSidecarsJsonResponse(verifiedBlobs []*blocks.VerifiedROBlob) *structs.SidecarsResponse {
-	resp := &structs.SidecarsResponse{Data: make([]*structs.Sidecar, len(verifiedBlobs))}
+func buildSidecarsJsonResponse(verifiedBlobs []*blocks.VerifiedROBlob) []*structs.Sidecar {
+	sidecars := make([]*structs.Sidecar, len(verifiedBlobs))
 	for i, sc := range verifiedBlobs {
 		proofs := make([]string, len(sc.CommitmentInclusionProof))
 		for j := range sc.CommitmentInclusionProof {
 			proofs[j] = hexutil.Encode(sc.CommitmentInclusionProof[j])
 		}
-		resp.Data[i] = &structs.Sidecar{
+		sidecars[i] = &structs.Sidecar{
 			Index:                    strconv.FormatUint(sc.Index, 10),
 			Blob:                     hexutil.Encode(sc.Blob),
 			KzgCommitment:            hexutil.Encode(sc.KzgCommitment),
@@ -108,7 +132,7 @@ func buildSidecarsJsonResponse(verifiedBlobs []*blocks.VerifiedROBlob) *structs.
 			CommitmentInclusionProof: proofs,
 		}
 	}
-	return resp
+	return sidecars
 }
 
 func buildSidecarsSSZResponse(verifiedBlobs []*blocks.VerifiedROBlob) ([]byte, error) {

beacon-chain/rpc/eth/blob/handlers_test.go

@@ -46,16 +46,20 @@ func TestBlobs(t *testing.T) {
 	}
 	blockRoot := blobs[0].BlockRoot()
 
+	mockChainService := &mockChain.ChainService{
+		FinalizedRoots: map[[32]byte]bool{},
+	}
+	s := &Server{
+		OptimisticModeFetcher: mockChainService,
+		FinalizationFetcher:   mockChainService,
+	}
+
 	t.Run("genesis", func(t *testing.T) {
 		u := "http://foo.example/genesis"
 		request := httptest.NewRequest("GET", u, nil)
 		writer := httptest.NewRecorder()
 		writer.Body = &bytes.Buffer{}
-		blocker := &lookup.BeaconDbBlocker{}
-		s := &Server{
-			Blocker: blocker,
-		}
-
+		s.Blocker = &lookup.BeaconDbBlocker{}
 		s.Blobs(writer, request)
 
 		assert.Equal(t, http.StatusBadRequest, writer.Code)
@@ -69,18 +73,14 @@ func TestBlobs(t *testing.T) {
 		request := httptest.NewRequest("GET", u, nil)
 		writer := httptest.NewRecorder()
 		writer.Body = &bytes.Buffer{}
-		blocker := &lookup.BeaconDbBlocker{
-			ChainInfoFetcher: &mockChain.ChainService{Root: blockRoot[:]},
+		s.Blocker = &lookup.BeaconDbBlocker{
+			ChainInfoFetcher: &mockChain.ChainService{Root: blockRoot[:], Block: denebBlock},
 			GenesisTimeFetcher: &testutil.MockGenesisTimeFetcher{
 				Genesis: time.Now(),
 			},
 			BeaconDB:    db,
 			BlobStorage: bs,
 		}
-		s := &Server{
-			Blocker: blocker,
-		}
-
 		s.Blobs(writer, request)
 
 		assert.Equal(t, http.StatusOK, writer.Code)
@@ -111,118 +111,96 @@ func TestBlobs(t *testing.T) {
 		assert.Equal(t, hexutil.Encode(blobs[3].Blob), sidecar.Blob)
 		assert.Equal(t, hexutil.Encode(blobs[3].KzgCommitment), sidecar.KzgCommitment)
 		assert.Equal(t, hexutil.Encode(blobs[3].KzgProof), sidecar.KzgProof)
+
+		require.Equal(t, "deneb", resp.Version)
+		require.Equal(t, false, resp.ExecutionOptimistic)
+		require.Equal(t, false, resp.Finalized)
 	})
 	t.Run("finalized", func(t *testing.T) {
 		u := "http://foo.example/finalized"
 		request := httptest.NewRequest("GET", u, nil)
 		writer := httptest.NewRecorder()
 		writer.Body = &bytes.Buffer{}
-		blocker := &lookup.BeaconDbBlocker{
-			ChainInfoFetcher: &mockChain.ChainService{FinalizedCheckPoint: &eth.Checkpoint{Root: blockRoot[:]}},
+		s.Blocker = &lookup.BeaconDbBlocker{
+			ChainInfoFetcher: &mockChain.ChainService{FinalizedCheckPoint: &eth.Checkpoint{Root: blockRoot[:]}, Block: denebBlock},
 			GenesisTimeFetcher: &testutil.MockGenesisTimeFetcher{
 				Genesis: time.Now(),
 			},
 			BeaconDB:    db,
 			BlobStorage: bs,
 		}
-		s := &Server{
-			Blocker: blocker,
-		}
-
 		s.Blobs(writer, request)
 
 		assert.Equal(t, http.StatusOK, writer.Code)
 		resp := &structs.SidecarsResponse{}
 		require.NoError(t, json.Unmarshal(writer.Body.Bytes(), resp))
 		require.Equal(t, 4, len(resp.Data))
-	})
-	t.Run("justified", func(t *testing.T) {
-		u := "http://foo.example/justified"
-		request := httptest.NewRequest("GET", u, nil)
-		writer := httptest.NewRecorder()
-		writer.Body = &bytes.Buffer{}
-		blocker := &lookup.BeaconDbBlocker{
-			ChainInfoFetcher: &mockChain.ChainService{CurrentJustifiedCheckPoint: &eth.Checkpoint{Root: blockRoot[:]}},
-			GenesisTimeFetcher: &testutil.MockGenesisTimeFetcher{
-				Genesis: time.Now(),
-			},
-			BeaconDB:    db,
-			BlobStorage: bs,
-		}
-		s := &Server{
-			Blocker: blocker,
-		}
 
-		s.Blobs(writer, request)
-
-		assert.Equal(t, http.StatusOK, writer.Code)
-		resp := &structs.SidecarsResponse{}
-		require.NoError(t, json.Unmarshal(writer.Body.Bytes(), resp))
-		require.Equal(t, 4, len(resp.Data))
+		require.Equal(t, "deneb", resp.Version)
+		require.Equal(t, false, resp.ExecutionOptimistic)
+		require.Equal(t, false, resp.Finalized)
 	})
 	t.Run("root", func(t *testing.T) {
 		u := "http://foo.example/" + hexutil.Encode(blockRoot[:])
 		request := httptest.NewRequest("GET", u, nil)
 		writer := httptest.NewRecorder()
 		writer.Body = &bytes.Buffer{}
-		blocker := &lookup.BeaconDbBlocker{
-			BeaconDB: db,
+		s.Blocker = &lookup.BeaconDbBlocker{
+			ChainInfoFetcher: &mockChain.ChainService{Block: denebBlock},
+			BeaconDB:         db,
 			GenesisTimeFetcher: &testutil.MockGenesisTimeFetcher{
 				Genesis: time.Now(),
 			},
 			BlobStorage: bs,
 		}
-		s := &Server{
-			Blocker: blocker,
-		}
-
 		s.Blobs(writer, request)
 
 		assert.Equal(t, http.StatusOK, writer.Code)
 		resp := &structs.SidecarsResponse{}
 		require.NoError(t, json.Unmarshal(writer.Body.Bytes(), resp))
 		require.Equal(t, 4, len(resp.Data))
+
+		require.Equal(t, "deneb", resp.Version)
+		require.Equal(t, false, resp.ExecutionOptimistic)
+		require.Equal(t, false, resp.Finalized)
 	})
 	t.Run("slot", func(t *testing.T) {
 		u := "http://foo.example/123"
 		request := httptest.NewRequest("GET", u, nil)
 		writer := httptest.NewRecorder()
 		writer.Body = &bytes.Buffer{}
-		blocker := &lookup.BeaconDbBlocker{
-			BeaconDB: db,
+		s.Blocker = &lookup.BeaconDbBlocker{
+			ChainInfoFetcher: &mockChain.ChainService{Block: denebBlock},
+			BeaconDB:         db,
 			GenesisTimeFetcher: &testutil.MockGenesisTimeFetcher{
 				Genesis: time.Now(),
 			},
 			BlobStorage: bs,
 		}
-		s := &Server{
-			Blocker: blocker,
-		}
-
 		s.Blobs(writer, request)
 
 		assert.Equal(t, http.StatusOK, writer.Code)
 		resp := &structs.SidecarsResponse{}
 		require.NoError(t, json.Unmarshal(writer.Body.Bytes(), resp))
 		require.Equal(t, 4, len(resp.Data))
+
+		require.Equal(t, "deneb", resp.Version)
+		require.Equal(t, false, resp.ExecutionOptimistic)
+		require.Equal(t, false, resp.Finalized)
 	})
 	t.Run("one blob only", func(t *testing.T) {
 		u := "http://foo.example/123?indices=2"
 		request := httptest.NewRequest("GET", u, nil)
 		writer := httptest.NewRecorder()
 		writer.Body = &bytes.Buffer{}
-		blocker := &lookup.BeaconDbBlocker{
-			ChainInfoFetcher: &mockChain.ChainService{FinalizedCheckPoint: &eth.Checkpoint{Root: blockRoot[:]}},
+		s.Blocker = &lookup.BeaconDbBlocker{
+			ChainInfoFetcher: &mockChain.ChainService{FinalizedCheckPoint: &eth.Checkpoint{Root: blockRoot[:]}, Block: denebBlock},
 			GenesisTimeFetcher: &testutil.MockGenesisTimeFetcher{
 				Genesis: time.Now(),
 			},
 			BeaconDB:    db,
 			BlobStorage: bs,
 		}
-		s := &Server{
-			Blocker: blocker,
-		}
-
 		s.Blobs(writer, request)
 
 		assert.Equal(t, http.StatusOK, writer.Code)
@@ -235,45 +213,47 @@ func TestBlobs(t *testing.T) {
 		assert.Equal(t, hexutil.Encode(blobs[2].Blob), sidecar.Blob)
 		assert.Equal(t, hexutil.Encode(blobs[2].KzgCommitment), sidecar.KzgCommitment)
 		assert.Equal(t, hexutil.Encode(blobs[2].KzgProof), sidecar.KzgProof)
+
+		require.Equal(t, "deneb", resp.Version)
+		require.Equal(t, false, resp.ExecutionOptimistic)
+		require.Equal(t, false, resp.Finalized)
 	})
 	t.Run("no blobs returns an empty array", func(t *testing.T) {
 		u := "http://foo.example/123"
 		request := httptest.NewRequest("GET", u, nil)
 		writer := httptest.NewRecorder()
 		writer.Body = &bytes.Buffer{}
-		blocker := &lookup.BeaconDbBlocker{
-			ChainInfoFetcher: &mockChain.ChainService{FinalizedCheckPoint: &eth.Checkpoint{Root: blockRoot[:]}},
+		s.Blocker = &lookup.BeaconDbBlocker{
+			ChainInfoFetcher: &mockChain.ChainService{FinalizedCheckPoint: &eth.Checkpoint{Root: blockRoot[:]}, Block: denebBlock},
 			GenesisTimeFetcher: &testutil.MockGenesisTimeFetcher{
 				Genesis: time.Now(),
 			},
 			BeaconDB:    db,
 			BlobStorage: filesystem.NewEphemeralBlobStorage(t), // new ephemeral storage
 		}
-		s := &Server{
-			Blocker: blocker,
-		}
 
 		s.Blobs(writer, request)
 		assert.Equal(t, http.StatusOK, writer.Code)
 		resp := &structs.SidecarsResponse{}
 		require.NoError(t, json.Unmarshal(writer.Body.Bytes(), resp))
 		require.Equal(t, len(resp.Data), 0)
+
+		require.Equal(t, "deneb", resp.Version)
+		require.Equal(t, false, resp.ExecutionOptimistic)
+		require.Equal(t, false, resp.Finalized)
 	})
 	t.Run("outside retention period returns 200 w/ empty list ", func(t *testing.T) {
 		u := "http://foo.example/123"
 		request := httptest.NewRequest("GET", u, nil)
 		writer := httptest.NewRecorder()
 		writer.Body = &bytes.Buffer{}
-		moc := &mockChain.ChainService{FinalizedCheckPoint: &eth.Checkpoint{Root: blockRoot[:]}}
-		blocker := &lookup.BeaconDbBlocker{
+		moc := &mockChain.ChainService{FinalizedCheckPoint: &eth.Checkpoint{Root: blockRoot[:]}, Block: denebBlock}
+		s.Blocker = &lookup.BeaconDbBlocker{
 			ChainInfoFetcher:   moc,
 			GenesisTimeFetcher: moc, // genesis time is set to 0 here, so it results in current epoch being extremely large
 			BeaconDB:           db,
 			BlobStorage:        bs,
 		}
-		s := &Server{
-			Blocker: blocker,
-		}
 
 		s.Blobs(writer, request)
 
@@ -281,6 +261,10 @@ func TestBlobs(t *testing.T) {
 		resp := &structs.SidecarsResponse{}
 		require.NoError(t, json.Unmarshal(writer.Body.Bytes(), resp))
 		require.Equal(t, 0, len(resp.Data))
+
+		require.Equal(t, "deneb", resp.Version)
+		require.Equal(t, false, resp.ExecutionOptimistic)
+		require.Equal(t, false, resp.Finalized)
 	})
 	t.Run("block without commitments returns 200 w/empty list ", func(t *testing.T) {
 		denebBlock, _ := util.GenerateTestDenebBlockWithSidecar(t, [32]byte{}, 333, 0)
@@ -293,17 +277,14 @@ func TestBlobs(t *testing.T) {
 		request := httptest.NewRequest("GET", u, nil)
 		writer := httptest.NewRecorder()
 		writer.Body = &bytes.Buffer{}
-		blocker := &lookup.BeaconDbBlocker{
-			ChainInfoFetcher: &mockChain.ChainService{FinalizedCheckPoint: &eth.Checkpoint{Root: blockRoot[:]}},
+		s.Blocker = &lookup.BeaconDbBlocker{
+			ChainInfoFetcher: &mockChain.ChainService{FinalizedCheckPoint: &eth.Checkpoint{Root: blockRoot[:]}, Block: denebBlock},
 			GenesisTimeFetcher: &testutil.MockGenesisTimeFetcher{
 				Genesis: time.Now(),
 			},
 			BeaconDB:    db,
 			BlobStorage: bs,
 		}
-		s := &Server{
-			Blocker: blocker,
-		}
 
 		s.Blobs(writer, request)
 
@@ -311,16 +292,17 @@ func TestBlobs(t *testing.T) {
 		resp := &structs.SidecarsResponse{}
 		require.NoError(t, json.Unmarshal(writer.Body.Bytes(), resp))
 		require.Equal(t, 0, len(resp.Data))
+
+		require.Equal(t, "deneb", resp.Version)
+		require.Equal(t, false, resp.ExecutionOptimistic)
+		require.Equal(t, false, resp.Finalized)
 	})
 	t.Run("slot before Deneb fork", func(t *testing.T) {
 		u := "http://foo.example/31"
 		request := httptest.NewRequest("GET", u, nil)
 		writer := httptest.NewRecorder()
 		writer.Body = &bytes.Buffer{}
-		blocker := &lookup.BeaconDbBlocker{}
-		s := &Server{
-			Blocker: blocker,
-		}
+		s.Blocker = &lookup.BeaconDbBlocker{}
 
 		s.Blobs(writer, request)
 
@@ -335,11 +317,7 @@ func TestBlobs(t *testing.T) {
 		request := httptest.NewRequest("GET", u, nil)
 		writer := httptest.NewRecorder()
 		writer.Body = &bytes.Buffer{}
-		blocker := &lookup.BeaconDbBlocker{}
-		s := &Server{
-			Blocker: blocker,
-		}
-
+		s.Blocker = &lookup.BeaconDbBlocker{}
 		s.Blobs(writer, request)
 
 		assert.Equal(t, http.StatusBadRequest, writer.Code)
@@ -354,7 +332,7 @@ func TestBlobs(t *testing.T) {
 		request.Header.Add("Accept", "application/octet-stream")
 		writer := httptest.NewRecorder()
 		writer.Body = &bytes.Buffer{}
-		blocker := &lookup.BeaconDbBlocker{
+		s.Blocker = &lookup.BeaconDbBlocker{
 			ChainInfoFetcher: &mockChain.ChainService{FinalizedCheckPoint: &eth.Checkpoint{Root: blockRoot[:]}},
 			GenesisTimeFetcher: &testutil.MockGenesisTimeFetcher{
 				Genesis: time.Now(),
@@ -362,10 +340,8 @@ func TestBlobs(t *testing.T) {
 			BeaconDB:    db,
 			BlobStorage: bs,
 		}
-		s := &Server{
-			Blocker: blocker,
-		}
 		s.Blobs(writer, request)
+
 		assert.Equal(t, http.StatusOK, writer.Code)
 		require.Equal(t, len(writer.Body.Bytes()), fieldparams.BlobSidecarSize) // size of each sidecar
 		// can directly unmarshal to sidecar since there's only 1
@@ -379,7 +355,7 @@ func TestBlobs(t *testing.T) {
 		request.Header.Add("Accept", "application/octet-stream")
 		writer := httptest.NewRecorder()
 		writer.Body = &bytes.Buffer{}
-		blocker := &lookup.BeaconDbBlocker{
+		s.Blocker = &lookup.BeaconDbBlocker{
 			ChainInfoFetcher: &mockChain.ChainService{FinalizedCheckPoint: &eth.Checkpoint{Root: blockRoot[:]}},
 			GenesisTimeFetcher: &testutil.MockGenesisTimeFetcher{
 				Genesis: time.Now(),
@@ -387,10 +363,8 @@ func TestBlobs(t *testing.T) {
 			BeaconDB:    db,
 			BlobStorage: bs,
 		}
-		s := &Server{
-			Blocker: blocker,
-		}
 		s.Blobs(writer, request)
+
 		assert.Equal(t, http.StatusOK, writer.Code)
 		require.Equal(t, len(writer.Body.Bytes()), fieldparams.BlobSidecarSize*4) // size of each sidecar
 	})

beacon-chain/rpc/eth/blob/server.go

@@ -1,9 +1,12 @@
 package blob
 
 import (
+	"github.com/prysmaticlabs/prysm/v5/beacon-chain/blockchain"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/rpc/lookup"
 )
 
 type Server struct {
-	Blocker lookup.Blocker
+	Blocker               lookup.Blocker
+	OptimisticModeFetcher blockchain.OptimisticModeFetcher
+	FinalizationFetcher   blockchain.FinalizationFetcher
 }

beacon-chain/rpc/eth/events/BUILD.bazel

@@ -20,18 +20,20 @@ go_library(
         "//beacon-chain/core/helpers:go_default_library",
         "//beacon-chain/core/time:go_default_library",
         "//config/params:go_default_library",
+        "//consensus-types/interfaces:go_default_library",
         "//consensus-types/payload-attribute:go_default_library",
         "//consensus-types/primitives:go_default_library",
         "//monitoring/tracing/trace:go_default_library",
         "//network/httputil:go_default_library",
         "//proto/engine/v1:go_default_library",
         "//proto/eth/v1:go_default_library",
-        "//proto/eth/v2:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
         "//runtime/version:go_default_library",
         "//time/slots:go_default_library",
         "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
+        "@com_github_prometheus_client_golang//prometheus:go_default_library",
+        "@com_github_prometheus_client_golang//prometheus/promauto:go_default_library",
         "@com_github_sirupsen_logrus//:go_default_library",
     ],
 )

beacon-chain/rpc/eth/events/events.go

@@ -12,6 +12,8 @@ import (
 
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/pkg/errors"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
 	"github.com/prysmaticlabs/prysm/v5/api"
 	"github.com/prysmaticlabs/prysm/v5/api/server/structs"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/feed"
@@ -20,13 +22,13 @@ import (
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/helpers"
 	chaintime "github.com/prysmaticlabs/prysm/v5/beacon-chain/core/time"
 	"github.com/prysmaticlabs/prysm/v5/config/params"
+	"github.com/prysmaticlabs/prysm/v5/consensus-types/interfaces"
 	payloadattribute "github.com/prysmaticlabs/prysm/v5/consensus-types/payload-attribute"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v5/monitoring/tracing/trace"
 	"github.com/prysmaticlabs/prysm/v5/network/httputil"
 	engine "github.com/prysmaticlabs/prysm/v5/proto/engine/v1"
 	ethpb "github.com/prysmaticlabs/prysm/v5/proto/eth/v1"
-	ethpbv2 "github.com/prysmaticlabs/prysm/v5/proto/eth/v2"
 	eth "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v5/runtime/version"
 	"github.com/prysmaticlabs/prysm/v5/time/slots"
@@ -76,6 +78,14 @@ var (
 	errWriterUnusable     = errors.New("http response writer is unusable")
 )
 
+var httpSSEErrorCount = promauto.NewCounterVec(
+	prometheus.CounterOpts{
+		Name: "http_sse_error_count",
+		Help: "Total HTTP errors for server sent events endpoint",
+	},
+	[]string{"endpoint", "error"},
+)
+
 // The eventStreamer uses lazyReaders to defer serialization until the moment the value is ready to be written to the client.
 type lazyReader func() io.Reader
 
@@ -145,6 +155,13 @@ func newTopicRequest(topics []string) (*topicRequest, error) {
 // Servers may send SSE comments beginning with ':' for any purpose,
 // including to keep the event stream connection alive in the presence of proxy servers.
 func (s *Server) StreamEvents(w http.ResponseWriter, r *http.Request) {
+	var err error
+	defer func() {
+		if err != nil {
+			httpSSEErrorCount.WithLabelValues(r.URL.Path, err.Error()).Inc()
+		}
+	}()
+
 	log.Debug("Starting StreamEvents handler")
 	ctx, span := trace.StartSpan(r.Context(), "events.StreamEvents")
 	defer span.End()
@@ -174,7 +191,7 @@ func (s *Server) StreamEvents(w http.ResponseWriter, r *http.Request) {
 	defer cancel()
 	es := newEventStreamer(buffSize, ka)
 
-	go es.outboxWriteLoop(ctx, cancel, sw)
+	go es.outboxWriteLoop(ctx, cancel, sw, r.URL.Path)
 	if err := es.recvEventLoop(ctx, cancel, topics, s); err != nil {
 		log.WithError(err).Debug("Shutting down StreamEvents handler.")
 	}
@@ -264,11 +281,12 @@ func newlineReader() io.Reader {
 
 // outboxWriteLoop runs in a separate goroutine. Its job is to write the values in the outbox to
 // the client as fast as the client can read them.
-func (es *eventStreamer) outboxWriteLoop(ctx context.Context, cancel context.CancelFunc, w *streamingResponseWriterController) {
+func (es *eventStreamer) outboxWriteLoop(ctx context.Context, cancel context.CancelFunc, w *streamingResponseWriterController, endpoint string) {
 	var err error
 	defer func() {
 		if err != nil {
 			log.WithError(err).Debug("Event streamer shutting down due to error.")
+			httpSSEErrorCount.WithLabelValues(endpoint, err.Error()).Inc()
 		}
 		es.exit()
 	}()
@@ -413,9 +431,9 @@ func topicForEvent(event *feed.Event) string {
 		return HeadTopic
 	case *ethpb.EventFinalizedCheckpoint:
 		return FinalizedCheckpointTopic
-	case *ethpbv2.LightClientFinalityUpdateWithVersion:
+	case interfaces.LightClientFinalityUpdate:
 		return LightClientFinalityUpdateTopic
-	case *ethpbv2.LightClientOptimisticUpdateWithVersion:
+	case interfaces.LightClientOptimisticUpdate:
 		return LightClientOptimisticUpdateTopic
 	case *ethpb.EventChainReorg:
 		return ChainReorgTopic
@@ -509,25 +527,25 @@ func (s *Server) lazyReaderForEvent(ctx context.Context, event *feed.Event, topi
 		return func() io.Reader {
 			return jsonMarshalReader(eventName, structs.FinalizedCheckpointEventFromV1(v))
 		}, nil
-	case *ethpbv2.LightClientFinalityUpdateWithVersion:
-		cv, err := structs.LightClientFinalityUpdateFromConsensus(v.Data)
+	case interfaces.LightClientFinalityUpdate:
+		cv, err := structs.LightClientFinalityUpdateFromConsensus(v)
 		if err != nil {
-			return nil, errors.Wrap(err, "LightClientFinalityUpdateWithVersion event conversion failure")
+			return nil, errors.Wrap(err, "LightClientFinalityUpdate conversion failure")
 		}
 		ev := &structs.LightClientFinalityUpdateEvent{
-			Version: version.String(int(v.Version)),
+			Version: version.String(v.Version()),
 			Data:    cv,
 		}
 		return func() io.Reader {
 			return jsonMarshalReader(eventName, ev)
 		}, nil
-	case *ethpbv2.LightClientOptimisticUpdateWithVersion:
-		cv, err := structs.LightClientOptimisticUpdateFromConsensus(v.Data)
+	case interfaces.LightClientOptimisticUpdate:
+		cv, err := structs.LightClientOptimisticUpdateFromConsensus(v)
 		if err != nil {
-			return nil, errors.Wrap(err, "LightClientOptimisticUpdateWithVersion event conversion failure")
+			return nil, errors.Wrap(err, "LightClientOptimisticUpdate conversion failure")
 		}
 		ev := &structs.LightClientOptimisticUpdateEvent{
-			Version: version.String(int(v.Version)),
+			Version: version.String(v.Version()),
 			Data:    cv,
 		}
 		return func() io.Reader {

beacon-chain/rpc/eth/events/server.go

@@ -12,7 +12,7 @@ import (
 	statefeed "github.com/prysmaticlabs/prysm/v5/beacon-chain/core/feed/state"
 )
 
-// Server defines a server implementation of the gRPC events service,
+// Server defines a server implementation of the http events service,
 // providing RPC endpoints to subscribe to events from the beacon node.
 type Server struct {
 	StateNotifier          statefeed.Notifier

beacon-chain/rpc/eth/light-client/BUILD.bazel

@@ -18,16 +18,13 @@ go_library(
         "//beacon-chain/rpc/eth/shared:go_default_library",
         "//beacon-chain/rpc/lookup:go_default_library",
         "//beacon-chain/state:go_default_library",
-        "//config/fieldparams:go_default_library",
+        "//config/features:go_default_library",
         "//config/params:go_default_library",
         "//consensus-types/interfaces:go_default_library",
         "//consensus-types/primitives:go_default_library",
         "//monitoring/tracing/trace:go_default_library",
         "//network/httputil:go_default_library",
-        "//proto/eth/v2:go_default_library",
-        "//proto/migration:go_default_library",
         "//runtime/version:go_default_library",
-        "//time/slots:go_default_library",
         "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
         "@com_github_wealdtech_go_bytesutil//:go_default_library",
@@ -46,17 +43,19 @@ go_test(
         "//beacon-chain/blockchain/testing:go_default_library",
         "//beacon-chain/core/helpers:go_default_library",
         "//beacon-chain/core/light-client:go_default_library",
+        "//beacon-chain/db/testing:go_default_library",
         "//beacon-chain/rpc/testutil:go_default_library",
         "//beacon-chain/state:go_default_library",
+        "//config/features:go_default_library",
         "//config/fieldparams:go_default_library",
         "//config/params:go_default_library",
         "//consensus-types/blocks:go_default_library",
         "//consensus-types/interfaces:go_default_library",
+        "//consensus-types/light-client:go_default_library",
         "//consensus-types/primitives:go_default_library",
-        "//proto/eth/v1:go_default_library",
-        "//proto/eth/v2:go_default_library",
+        "//proto/engine/v1:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
-        "//testing/assert:go_default_library",
+        "//runtime/version:go_default_library",
         "//testing/require:go_default_library",
         "//testing/util:go_default_library",
         "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",

beacon-chain/rpc/eth/light-client/handlers.go

@@ -10,11 +10,11 @@ import (
 	"github.com/pkg/errors"
 	"github.com/prysmaticlabs/prysm/v5/api"
 	"github.com/prysmaticlabs/prysm/v5/api/server/structs"
+	lightclient "github.com/prysmaticlabs/prysm/v5/beacon-chain/core/light-client"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/rpc/eth/shared"
-	"github.com/prysmaticlabs/prysm/v5/beacon-chain/state"
+	"github.com/prysmaticlabs/prysm/v5/config/features"
 	"github.com/prysmaticlabs/prysm/v5/config/params"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/interfaces"
-	types "github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v5/monitoring/tracing/trace"
 	"github.com/prysmaticlabs/prysm/v5/network/httputil"
 	"github.com/prysmaticlabs/prysm/v5/runtime/version"
@@ -23,6 +23,11 @@ import (
 
 // GetLightClientBootstrap - implements https://github.com/ethereum/beacon-APIs/blob/263f4ed6c263c967f13279c7a9f5629b51c5fc55/apis/beacon/light_client/bootstrap.yaml
 func (s *Server) GetLightClientBootstrap(w http.ResponseWriter, req *http.Request) {
+	if !features.Get().EnableLightClient {
+		httputil.HandleError(w, "Light client feature flag is not enabled", http.StatusNotFound)
+		return
+	}
+
 	// Prepare
 	ctx, span := trace.StartSpan(req.Context(), "beacon.GetLightClientBootstrap")
 	defer span.End()
@@ -47,42 +52,51 @@ func (s *Server) GetLightClientBootstrap(w http.ResponseWriter, req *http.Reques
 		return
 	}
 
-	bootstrap, err := createLightClientBootstrap(ctx, state, blk)
+	bootstrap, err := lightclient.NewLightClientBootstrapFromBeaconState(ctx, s.ChainInfoFetcher.CurrentSlot(), state, blk)
 	if err != nil {
 		httputil.HandleError(w, "could not get light client bootstrap: "+err.Error(), http.StatusInternalServerError)
 		return
 	}
-	response := &structs.LightClientBootstrapResponse{
-		Version: version.String(blk.Version()),
-		Data:    bootstrap,
-	}
-	w.Header().Set(api.VersionHeader, version.String(version.Deneb))
+	w.Header().Set(api.VersionHeader, version.String(bootstrap.Version()))
 
-	httputil.WriteJson(w, response)
+	if httputil.RespondWithSsz(req) {
+		ssz, err := bootstrap.MarshalSSZ()
+		if err != nil {
+			httputil.HandleError(w, "could not marshal bootstrap to SSZ: "+err.Error(), http.StatusInternalServerError)
+			return
+		}
+		httputil.WriteSsz(w, ssz, "light_client_bootstrap.ssz")
+	} else {
+		data, err := structs.LightClientBootstrapFromConsensus(bootstrap)
+		if err != nil {
+			httputil.HandleError(w, "could not marshal bootstrap to JSON: "+err.Error(), http.StatusInternalServerError)
+			return
+		}
+		response := &structs.LightClientBootstrapResponse{
+			Version: version.String(bootstrap.Version()),
+			Data:    data,
+		}
+		httputil.WriteJson(w, response)
+	}
 }
 
 // GetLightClientUpdatesByRange - implements https://github.com/ethereum/beacon-APIs/blob/263f4ed6c263c967f13279c7a9f5629b51c5fc55/apis/beacon/light_client/updates.yaml
 func (s *Server) GetLightClientUpdatesByRange(w http.ResponseWriter, req *http.Request) {
-	// Prepare
+	if !features.Get().EnableLightClient {
+		httputil.HandleError(w, "Light client feature flag is not enabled", http.StatusNotFound)
+		return
+	}
+
 	ctx, span := trace.StartSpan(req.Context(), "beacon.GetLightClientUpdatesByRange")
 	defer span.End()
 
-	// Determine slots per period
 	config := params.BeaconConfig()
-	slotsPerPeriod := uint64(config.EpochsPerSyncCommitteePeriod) * uint64(config.SlotsPerEpoch)
 
-	// Adjust count based on configuration
 	_, count, gotCount := shared.UintFromQuery(w, req, "count", true)
 	if !gotCount {
 		return
 	} else if count == 0 {
-		httputil.HandleError(w, fmt.Sprintf("got invalid 'count' query variable '%d': count must be greater than 0", count), http.StatusInternalServerError)
-		return
-	}
-
-	// Determine the start and end periods
-	_, startPeriod, gotStartPeriod := shared.UintFromQuery(w, req, "start_period", true)
-	if !gotStartPeriod {
+		httputil.HandleError(w, fmt.Sprintf("Got invalid 'count' query variable '%d': count must be greater than 0", count), http.StatusBadRequest)
 		return
 	}
 
@@ -90,142 +104,50 @@ func (s *Server) GetLightClientUpdatesByRange(w http.ResponseWriter, req *http.R
 		count = config.MaxRequestLightClientUpdates
 	}
 
-	// max possible slot is current head
-	headState, err := s.HeadFetcher.HeadState(ctx)
-	if err != nil {
-		httputil.HandleError(w, "could not get head state: "+err.Error(), http.StatusInternalServerError)
+	_, startPeriod, gotStartPeriod := shared.UintFromQuery(w, req, "start_period", true)
+	if !gotStartPeriod {
 		return
 	}
 
-	maxSlot := uint64(headState.Slot())
-
-	// min possible slot is Altair fork period
-	minSlot := uint64(config.AltairForkEpoch) * uint64(config.SlotsPerEpoch)
-
-	// Adjust startPeriod, the end of start period must be later than Altair fork epoch, otherwise, can not get the sync committee votes
-	startPeriodEndSlot := (startPeriod+1)*slotsPerPeriod - 1
-	if startPeriodEndSlot < minSlot {
-		startPeriod = minSlot / slotsPerPeriod
-	}
-
-	// Get the initial endPeriod, then we will adjust
 	endPeriod := startPeriod + count - 1
 
-	// Adjust endPeriod, the end of end period must be earlier than current head slot
-	endPeriodEndSlot := (endPeriod+1)*slotsPerPeriod - 1
-	if endPeriodEndSlot > maxSlot {
-		endPeriod = maxSlot / slotsPerPeriod
+	// get updates
+	updatesMap, err := s.BeaconDB.LightClientUpdates(ctx, startPeriod, endPeriod)
+	if err != nil {
+		httputil.HandleError(w, "Could not get light client updates from DB: "+err.Error(), http.StatusInternalServerError)
+		return
 	}
 
-	// Populate updates
-	var updates []*structs.LightClientUpdateResponse
-	for period := startPeriod; period <= endPeriod; period++ {
-		// Get the last known state of the period,
-		//    1. We wish the block has a parent in the same period if possible
-		//	  2. We wish the block has a state in the same period
-		lastSlotInPeriod := period*slotsPerPeriod + slotsPerPeriod - 1
-		if lastSlotInPeriod > maxSlot {
-			lastSlotInPeriod = maxSlot
-		}
-		firstSlotInPeriod := period * slotsPerPeriod
-
-		// Let's not use the first slot in the period, otherwise the attested header will be in previous period
-		firstSlotInPeriod++
-
-		var state state.BeaconState
-		var block interfaces.ReadOnlySignedBeaconBlock
-		for slot := lastSlotInPeriod; slot >= firstSlotInPeriod; slot-- {
-			state, err = s.Stater.StateBySlot(ctx, types.Slot(slot))
-			if err != nil {
-				continue
-			}
-
-			// Get the block
-			latestBlockHeader := state.LatestBlockHeader()
-			latestStateRoot, err := state.HashTreeRoot(ctx)
-			if err != nil {
-				continue
-			}
-			latestBlockHeader.StateRoot = latestStateRoot[:]
-			blockRoot, err := latestBlockHeader.HashTreeRoot()
-			if err != nil {
-				continue
-			}
-
-			block, err = s.Blocker.Block(ctx, blockRoot[:])
-			if err != nil || block == nil {
-				continue
-			}
-
-			syncAggregate, err := block.Block().Body().SyncAggregate()
-			if err != nil || syncAggregate == nil {
-				continue
-			}
-
-			if syncAggregate.SyncCommitteeBits.Count()*3 < config.SyncCommitteeSize*2 {
-				// Not enough votes
-				continue
-			}
+	updates := make([]*structs.LightClientUpdateResponse, 0, len(updatesMap))
 
+	for i := startPeriod; i <= endPeriod; i++ {
+		update, ok := updatesMap[i]
+		if !ok {
+			// Only return the first contiguous range of updates
 			break
 		}
 
-		if block == nil {
-			// No valid block found for the period
-			continue
-		}
-
-		// Get attested state
-		attestedRoot := block.Block().ParentRoot()
-		attestedBlock, err := s.Blocker.Block(ctx, attestedRoot[:])
-		if err != nil || attestedBlock == nil {
-			continue
-		}
-
-		attestedSlot := attestedBlock.Block().Slot()
-		attestedState, err := s.Stater.StateBySlot(ctx, attestedSlot)
+		updateJson, err := structs.LightClientUpdateFromConsensus(update)
 		if err != nil {
-			continue
+			httputil.HandleError(w, "Could not convert light client update: "+err.Error(), http.StatusInternalServerError)
+			return
 		}
-
-		// Get finalized block
-		var finalizedBlock interfaces.ReadOnlySignedBeaconBlock
-		finalizedCheckPoint := attestedState.FinalizedCheckpoint()
-		if finalizedCheckPoint != nil {
-			finalizedRoot := bytesutil.ToBytes32(finalizedCheckPoint.Root)
-			finalizedBlock, err = s.Blocker.Block(ctx, finalizedRoot[:])
-			if err != nil {
-				finalizedBlock = nil
-			}
-		}
-
-		update, err := newLightClientUpdateFromBeaconState(
-			ctx,
-			state,
-			block,
-			attestedState,
-			attestedBlock,
-			finalizedBlock,
-		)
-
-		if err == nil {
-			updates = append(updates, &structs.LightClientUpdateResponse{
-				Version: version.String(attestedState.Version()),
-				Data:    update,
-			})
+		updateResponse := &structs.LightClientUpdateResponse{
+			Version: version.String(update.Version()),
+			Data:    updateJson,
 		}
+		updates = append(updates, updateResponse)
 	}
-
-	if len(updates) == 0 {
-		httputil.HandleError(w, "no updates found", http.StatusNotFound)
-		return
-	}
-
 	httputil.WriteJson(w, updates)
 }
 
 // GetLightClientFinalityUpdate - implements https://github.com/ethereum/beacon-APIs/blob/263f4ed6c263c967f13279c7a9f5629b51c5fc55/apis/beacon/light_client/finality_update.yaml
 func (s *Server) GetLightClientFinalityUpdate(w http.ResponseWriter, req *http.Request) {
+	if !features.Get().EnableLightClient {
+		httputil.HandleError(w, "Light client feature flag is not enabled", http.StatusNotFound)
+		return
+	}
+
 	ctx, span := trace.StartSpan(req.Context(), "beacon.GetLightClientFinalityUpdate")
 	defer span.End()
 
@@ -268,7 +190,7 @@ func (s *Server) GetLightClientFinalityUpdate(w http.ResponseWriter, req *http.R
 		return
 	}
 
-	update, err := newLightClientFinalityUpdateFromBeaconState(ctx, st, block, attestedState, attestedBlock, finalizedBlock)
+	update, err := newLightClientFinalityUpdateFromBeaconState(ctx, s.ChainInfoFetcher.CurrentSlot(), st, block, attestedState, attestedBlock, finalizedBlock)
 	if err != nil {
 		httputil.HandleError(w, "Could not get light client finality update: "+err.Error(), http.StatusInternalServerError)
 		return
@@ -284,6 +206,11 @@ func (s *Server) GetLightClientFinalityUpdate(w http.ResponseWriter, req *http.R
 
 // GetLightClientOptimisticUpdate - implements https://github.com/ethereum/beacon-APIs/blob/263f4ed6c263c967f13279c7a9f5629b51c5fc55/apis/beacon/light_client/optimistic_update.yaml
 func (s *Server) GetLightClientOptimisticUpdate(w http.ResponseWriter, req *http.Request) {
+	if !features.Get().EnableLightClient {
+		httputil.HandleError(w, "Light client feature flag is not enabled", http.StatusNotFound)
+		return
+	}
+
 	ctx, span := trace.StartSpan(req.Context(), "beacon.GetLightClientOptimisticUpdate")
 	defer span.End()
 
@@ -313,7 +240,7 @@ func (s *Server) GetLightClientOptimisticUpdate(w http.ResponseWriter, req *http
 		return
 	}
 
-	update, err := newLightClientOptimisticUpdateFromBeaconState(ctx, st, block, attestedState, attestedBlock)
+	update, err := newLightClientOptimisticUpdateFromBeaconState(ctx, s.ChainInfoFetcher.CurrentSlot(), st, block, attestedState, attestedBlock)
 	if err != nil {
 		httputil.HandleError(w, "Could not get light client optimistic update: "+err.Error(), http.StatusInternalServerError)
 		return

beacon-chain/rpc/eth/light-client/helpers.go

@@ -2,274 +2,25 @@ package lightclient
 
 import (
 	"context"
-	"encoding/json"
-	"fmt"
-	"reflect"
 
-	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/v5/proto/migration"
+	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
 
-	lightclient "github.com/prysmaticlabs/prysm/v5/beacon-chain/core/light-client"
-	"github.com/prysmaticlabs/prysm/v5/runtime/version"
-
-	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/prysmaticlabs/prysm/v5/api/server/structs"
+	lightclient "github.com/prysmaticlabs/prysm/v5/beacon-chain/core/light-client"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/state"
-	fieldparams "github.com/prysmaticlabs/prysm/v5/config/fieldparams"
-	"github.com/prysmaticlabs/prysm/v5/config/params"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/interfaces"
-	v2 "github.com/prysmaticlabs/prysm/v5/proto/eth/v2"
-	"github.com/prysmaticlabs/prysm/v5/time/slots"
 )
 
-func createLightClientBootstrap(ctx context.Context, state state.BeaconState, blk interfaces.ReadOnlySignedBeaconBlock) (*structs.LightClientBootstrap, error) {
-	switch blk.Version() {
-	case version.Phase0:
-		return nil, fmt.Errorf("light client bootstrap is not supported for phase0")
-	case version.Altair, version.Bellatrix:
-		return createLightClientBootstrapAltair(ctx, state, blk)
-	case version.Capella:
-		return createLightClientBootstrapCapella(ctx, state, blk)
-	case version.Deneb, version.Electra:
-		return createLightClientBootstrapDeneb(ctx, state, blk)
-	}
-	return nil, fmt.Errorf("unsupported block version %s", version.String(blk.Version()))
-}
-
-func createLightClientBootstrapAltair(ctx context.Context, state state.BeaconState, block interfaces.ReadOnlySignedBeaconBlock) (*structs.LightClientBootstrap, error) {
-	// assert compute_epoch_at_slot(state.slot) >= ALTAIR_FORK_EPOCH
-	if slots.ToEpoch(state.Slot()) < params.BeaconConfig().AltairForkEpoch {
-		return nil, fmt.Errorf("light client bootstrap is not supported before Altair, invalid slot %d", state.Slot())
-	}
-
-	// assert state.slot == state.latest_block_header.slot
-	latestBlockHeader := state.LatestBlockHeader()
-	if state.Slot() != latestBlockHeader.Slot {
-		return nil, fmt.Errorf("state slot %d not equal to latest block header slot %d", state.Slot(), latestBlockHeader.Slot)
-	}
-
-	// header.state_root = hash_tree_root(state)
-	stateRoot, err := state.HashTreeRoot(ctx)
-	if err != nil {
-		return nil, errors.Wrap(err, "could not get state root")
-	}
-	latestBlockHeader.StateRoot = stateRoot[:]
-
-	// assert hash_tree_root(header) == hash_tree_root(block.message)
-	latestBlockHeaderRoot, err := latestBlockHeader.HashTreeRoot()
-	if err != nil {
-		return nil, errors.Wrap(err, "could not get latest block header root")
-	}
-	beaconBlockRoot, err := block.Block().HashTreeRoot()
-	if err != nil {
-		return nil, errors.Wrap(err, "could not get block root")
-	}
-	if latestBlockHeaderRoot != beaconBlockRoot {
-		return nil, fmt.Errorf("latest block header root %#x not equal to block root %#x", latestBlockHeaderRoot, beaconBlockRoot)
-	}
-
-	lightClientHeaderContainer, err := lightclient.BlockToLightClientHeader(block)
-	if err != nil {
-		return nil, errors.Wrap(err, "could not convert block to light client header")
-	}
-	lightClientHeader := lightClientHeaderContainer.GetHeaderAltair()
-
-	apiLightClientHeader := &structs.LightClientHeader{
-		Beacon: structs.BeaconBlockHeaderFromConsensus(migration.V1HeaderToV1Alpha1(lightClientHeader.Beacon)),
-	}
-
-	headerJSON, err := json.Marshal(apiLightClientHeader)
-	if err != nil {
-		return nil, errors.Wrap(err, "could not convert header to raw message")
-	}
-	currentSyncCommittee, err := state.CurrentSyncCommittee()
-	if err != nil {
-		return nil, errors.Wrap(err, "could not get current sync committee")
-	}
-	currentSyncCommitteeProof, err := state.CurrentSyncCommitteeProof(ctx)
-	if err != nil {
-		return nil, errors.Wrap(err, "could not get current sync committee proof")
-	}
-
-	branch := make([]string, fieldparams.SyncCommitteeBranchDepth)
-	for i, proof := range currentSyncCommitteeProof {
-		branch[i] = hexutil.Encode(proof)
-	}
-	result := &structs.LightClientBootstrap{
-		Header:                     headerJSON,
-		CurrentSyncCommittee:       structs.SyncCommitteeFromConsensus(currentSyncCommittee),
-		CurrentSyncCommitteeBranch: branch,
-	}
-
-	return result, nil
-}
-
-func createLightClientBootstrapCapella(ctx context.Context, state state.BeaconState, block interfaces.ReadOnlySignedBeaconBlock) (*structs.LightClientBootstrap, error) {
-	// assert compute_epoch_at_slot(state.slot) >= CAPELLA_FORK_EPOCH
-	if slots.ToEpoch(state.Slot()) < params.BeaconConfig().CapellaForkEpoch {
-		return nil, fmt.Errorf("creating Capella light client bootstrap is not supported before Capella, invalid slot %d", state.Slot())
-	}
-
-	// assert state.slot == state.latest_block_header.slot
-	latestBlockHeader := state.LatestBlockHeader()
-	if state.Slot() != latestBlockHeader.Slot {
-		return nil, fmt.Errorf("state slot %d not equal to latest block header slot %d", state.Slot(), latestBlockHeader.Slot)
-	}
-
-	// header.state_root = hash_tree_root(state)
-	stateRoot, err := state.HashTreeRoot(ctx)
-	if err != nil {
-		return nil, errors.Wrap(err, "could not get state root")
-	}
-	latestBlockHeader.StateRoot = stateRoot[:]
-
-	// assert hash_tree_root(header) == hash_tree_root(block.message)
-	latestBlockHeaderRoot, err := latestBlockHeader.HashTreeRoot()
-	if err != nil {
-		return nil, errors.Wrap(err, "could not get latest block header root")
-	}
-	beaconBlockRoot, err := block.Block().HashTreeRoot()
-	if err != nil {
-		return nil, errors.Wrap(err, "could not get block root")
-	}
-	if latestBlockHeaderRoot != beaconBlockRoot {
-		return nil, fmt.Errorf("latest block header root %#x not equal to block root %#x", latestBlockHeaderRoot, beaconBlockRoot)
-	}
-
-	lightClientHeaderContainer, err := lightclient.BlockToLightClientHeader(block)
-	if err != nil {
-		return nil, errors.Wrap(err, "could not convert block to light client header")
-	}
-	lightClientHeader := lightClientHeaderContainer.GetHeaderCapella()
-
-	apiLightClientHeader := &structs.LightClientHeader{
-		Beacon: structs.BeaconBlockHeaderFromConsensus(migration.V1HeaderToV1Alpha1(lightClientHeader.Beacon)),
-	}
-
-	headerJSON, err := json.Marshal(apiLightClientHeader)
-	if err != nil {
-		return nil, errors.Wrap(err, "could not convert header to raw message")
-	}
-	currentSyncCommittee, err := state.CurrentSyncCommittee()
-	if err != nil {
-		return nil, errors.Wrap(err, "could not get current sync committee")
-	}
-	currentSyncCommitteeProof, err := state.CurrentSyncCommitteeProof(ctx)
-	if err != nil {
-		return nil, errors.Wrap(err, "could not get current sync committee proof")
-	}
-
-	branch := make([]string, fieldparams.SyncCommitteeBranchDepth)
-	for i, proof := range currentSyncCommitteeProof {
-		branch[i] = hexutil.Encode(proof)
-	}
-	result := &structs.LightClientBootstrap{
-		Header:                     headerJSON,
-		CurrentSyncCommittee:       structs.SyncCommitteeFromConsensus(currentSyncCommittee),
-		CurrentSyncCommitteeBranch: branch,
-	}
-
-	return result, nil
-}
-
-func createLightClientBootstrapDeneb(ctx context.Context, state state.BeaconState, block interfaces.ReadOnlySignedBeaconBlock) (*structs.LightClientBootstrap, error) {
-	// assert compute_epoch_at_slot(state.slot) >= DENEB_FORK_EPOCH
-	if slots.ToEpoch(state.Slot()) < params.BeaconConfig().DenebForkEpoch {
-		return nil, fmt.Errorf("creating Deneb light client bootstrap is not supported before Deneb, invalid slot %d", state.Slot())
-	}
-
-	// assert state.slot == state.latest_block_header.slot
-	latestBlockHeader := state.LatestBlockHeader()
-	if state.Slot() != latestBlockHeader.Slot {
-		return nil, fmt.Errorf("state slot %d not equal to latest block header slot %d", state.Slot(), latestBlockHeader.Slot)
-	}
-
-	// header.state_root = hash_tree_root(state)
-	stateRoot, err := state.HashTreeRoot(ctx)
-	if err != nil {
-		return nil, errors.Wrap(err, "could not get state root")
-	}
-	latestBlockHeader.StateRoot = stateRoot[:]
-
-	// assert hash_tree_root(header) == hash_tree_root(block.message)
-	latestBlockHeaderRoot, err := latestBlockHeader.HashTreeRoot()
-	if err != nil {
-		return nil, errors.Wrap(err, "could not get latest block header root")
-	}
-	beaconBlockRoot, err := block.Block().HashTreeRoot()
-	if err != nil {
-		return nil, errors.Wrap(err, "could not get block root")
-	}
-	if latestBlockHeaderRoot != beaconBlockRoot {
-		return nil, fmt.Errorf("latest block header root %#x not equal to block root %#x", latestBlockHeaderRoot, beaconBlockRoot)
-	}
-
-	lightClientHeaderContainer, err := lightclient.BlockToLightClientHeader(block)
-	if err != nil {
-		return nil, errors.Wrap(err, "could not convert block to light client header")
-	}
-	lightClientHeader := lightClientHeaderContainer.GetHeaderDeneb()
-
-	apiLightClientHeader := &structs.LightClientHeader{
-		Beacon: structs.BeaconBlockHeaderFromConsensus(migration.V1HeaderToV1Alpha1(lightClientHeader.Beacon)),
-	}
-
-	headerJSON, err := json.Marshal(apiLightClientHeader)
-	if err != nil {
-		return nil, errors.Wrap(err, "could not convert header to raw message")
-	}
-	currentSyncCommittee, err := state.CurrentSyncCommittee()
-	if err != nil {
-		return nil, errors.Wrap(err, "could not get current sync committee")
-	}
-	currentSyncCommitteeProof, err := state.CurrentSyncCommitteeProof(ctx)
-	if err != nil {
-		return nil, errors.Wrap(err, "could not get current sync committee proof")
-	}
-	var branch []string
-	switch block.Version() {
-	case version.Deneb:
-		branch = make([]string, fieldparams.SyncCommitteeBranchDepth)
-	case version.Electra:
-		branch = make([]string, fieldparams.SyncCommitteeBranchDepthElectra)
-	}
-	for i, proof := range currentSyncCommitteeProof {
-		branch[i] = hexutil.Encode(proof)
-	}
-	result := &structs.LightClientBootstrap{
-		Header:                     headerJSON,
-		CurrentSyncCommittee:       structs.SyncCommitteeFromConsensus(currentSyncCommittee),
-		CurrentSyncCommitteeBranch: branch,
-	}
-
-	return result, nil
-}
-
-func newLightClientUpdateFromBeaconState(
-	ctx context.Context,
-	state state.BeaconState,
-	block interfaces.ReadOnlySignedBeaconBlock,
-	attestedState state.BeaconState,
-	attestedBlock interfaces.ReadOnlySignedBeaconBlock,
-	finalizedBlock interfaces.ReadOnlySignedBeaconBlock,
-) (*structs.LightClientUpdate, error) {
-	result, err := lightclient.NewLightClientUpdateFromBeaconState(ctx, state, block, attestedState, attestedBlock, finalizedBlock)
-	if err != nil {
-		return nil, err
-	}
-
-	return structs.LightClientUpdateFromConsensus(result)
-}
-
 func newLightClientFinalityUpdateFromBeaconState(
 	ctx context.Context,
+	currentSlot primitives.Slot,
 	state state.BeaconState,
 	block interfaces.ReadOnlySignedBeaconBlock,
 	attestedState state.BeaconState,
 	attestedBlock interfaces.ReadOnlySignedBeaconBlock,
 	finalizedBlock interfaces.ReadOnlySignedBeaconBlock,
 ) (*structs.LightClientFinalityUpdate, error) {
-	result, err := lightclient.NewLightClientFinalityUpdateFromBeaconState(ctx, state, block, attestedState, attestedBlock, finalizedBlock)
+	result, err := lightclient.NewLightClientFinalityUpdateFromBeaconState(ctx, currentSlot, state, block, attestedState, attestedBlock, finalizedBlock)
 	if err != nil {
 		return nil, err
 	}
@@ -279,94 +30,16 @@ func newLightClientFinalityUpdateFromBeaconState(
 
 func newLightClientOptimisticUpdateFromBeaconState(
 	ctx context.Context,
+	currentSlot primitives.Slot,
 	state state.BeaconState,
 	block interfaces.ReadOnlySignedBeaconBlock,
 	attestedState state.BeaconState,
 	attestedBlock interfaces.ReadOnlySignedBeaconBlock,
 ) (*structs.LightClientOptimisticUpdate, error) {
-	result, err := lightclient.NewLightClientOptimisticUpdateFromBeaconState(ctx, state, block, attestedState, attestedBlock)
+	result, err := lightclient.NewLightClientOptimisticUpdateFromBeaconState(ctx, currentSlot, state, block, attestedState, attestedBlock)
 	if err != nil {
 		return nil, err
 	}
 
 	return structs.LightClientOptimisticUpdateFromConsensus(result)
 }
-
-func IsSyncCommitteeUpdate(update *v2.LightClientUpdate) bool {
-	nextSyncCommitteeBranch := make([][]byte, fieldparams.SyncCommitteeBranchDepth)
-	return !reflect.DeepEqual(update.NextSyncCommitteeBranch, nextSyncCommitteeBranch)
-}
-
-func IsFinalityUpdate(update *v2.LightClientUpdate) bool {
-	finalityBranch := make([][]byte, lightclient.FinalityBranchNumOfLeaves)
-	return !reflect.DeepEqual(update.FinalityBranch, finalityBranch)
-}
-
-func IsBetterUpdate(newUpdate, oldUpdate *v2.LightClientUpdate) (bool, error) {
-	maxActiveParticipants := newUpdate.SyncAggregate.SyncCommitteeBits.Len()
-	newNumActiveParticipants := newUpdate.SyncAggregate.SyncCommitteeBits.Count()
-	oldNumActiveParticipants := oldUpdate.SyncAggregate.SyncCommitteeBits.Count()
-	newHasSupermajority := newNumActiveParticipants*3 >= maxActiveParticipants*2
-	oldHasSupermajority := oldNumActiveParticipants*3 >= maxActiveParticipants*2
-
-	if newHasSupermajority != oldHasSupermajority {
-		return newHasSupermajority, nil
-	}
-	if !newHasSupermajority && newNumActiveParticipants != oldNumActiveParticipants {
-		return newNumActiveParticipants > oldNumActiveParticipants, nil
-	}
-
-	newUpdateAttestedHeaderBeacon, err := newUpdate.AttestedHeader.GetBeacon()
-	if err != nil {
-		return false, errors.Wrap(err, "could not get attested header beacon")
-	}
-	oldUpdateAttestedHeaderBeacon, err := oldUpdate.AttestedHeader.GetBeacon()
-	if err != nil {
-		return false, errors.Wrap(err, "could not get attested header beacon")
-	}
-
-	// Compare presence of relevant sync committee
-	newHasRelevantSyncCommittee := IsSyncCommitteeUpdate(newUpdate) && (slots.SyncCommitteePeriod(slots.ToEpoch(newUpdateAttestedHeaderBeacon.Slot)) == slots.SyncCommitteePeriod(slots.ToEpoch(newUpdate.SignatureSlot)))
-	oldHasRelevantSyncCommittee := IsSyncCommitteeUpdate(oldUpdate) && (slots.SyncCommitteePeriod(slots.ToEpoch(oldUpdateAttestedHeaderBeacon.Slot)) == slots.SyncCommitteePeriod(slots.ToEpoch(oldUpdate.SignatureSlot)))
-
-	if newHasRelevantSyncCommittee != oldHasRelevantSyncCommittee {
-		return newHasRelevantSyncCommittee, nil
-	}
-
-	// Compare indication of any finality
-	newHasFinality := IsFinalityUpdate(newUpdate)
-	oldHasFinality := IsFinalityUpdate(oldUpdate)
-	if newHasFinality != oldHasFinality {
-		return newHasFinality, nil
-	}
-
-	newUpdateFinalizedHeaderBeacon, err := newUpdate.FinalizedHeader.GetBeacon()
-	if err != nil {
-		return false, errors.Wrap(err, "could not get finalized header beacon")
-	}
-	oldUpdateFinalizedHeaderBeacon, err := oldUpdate.FinalizedHeader.GetBeacon()
-	if err != nil {
-		return false, errors.Wrap(err, "could not get finalized header beacon")
-	}
-
-	// Compare sync committee finality
-	if newHasFinality {
-		newHasSyncCommitteeFinality := slots.SyncCommitteePeriod(slots.ToEpoch(newUpdateFinalizedHeaderBeacon.Slot)) == slots.SyncCommitteePeriod(slots.ToEpoch(newUpdateAttestedHeaderBeacon.Slot))
-		oldHasSyncCommitteeFinality := slots.SyncCommitteePeriod(slots.ToEpoch(oldUpdateFinalizedHeaderBeacon.Slot)) == slots.SyncCommitteePeriod(slots.ToEpoch(oldUpdateAttestedHeaderBeacon.Slot))
-
-		if newHasSyncCommitteeFinality != oldHasSyncCommitteeFinality {
-			return newHasSyncCommitteeFinality, nil
-		}
-	}
-
-	// Tiebreaker 1: Sync committee participation beyond supermajority
-	if newNumActiveParticipants != oldNumActiveParticipants {
-		return newNumActiveParticipants > oldNumActiveParticipants, nil
-	}
-
-	// Tiebreaker 2: Prefer older data (fewer changes to best)
-	if newUpdateAttestedHeaderBeacon.Slot != oldUpdateAttestedHeaderBeacon.Slot {
-		return newUpdateAttestedHeaderBeacon.Slot < oldUpdateAttestedHeaderBeacon.Slot, nil
-	}
-	return newUpdate.SignatureSlot < oldUpdate.SignatureSlot, nil
-}

beacon-chain/rpc/eth/light-client/helpers_test.go

@@ -1,616 +1 @@
 package lightclient
-
-import (
-	"testing"
-
-	lightclient "github.com/prysmaticlabs/prysm/v5/beacon-chain/core/light-client"
-
-	fieldparams "github.com/prysmaticlabs/prysm/v5/config/fieldparams"
-	ethpbv1 "github.com/prysmaticlabs/prysm/v5/proto/eth/v1"
-	ethpbv2 "github.com/prysmaticlabs/prysm/v5/proto/eth/v2"
-	"github.com/prysmaticlabs/prysm/v5/testing/assert"
-)
-
-// When the update has relevant sync committee
-func createNonEmptySyncCommitteeBranch() [][]byte {
-	res := make([][]byte, fieldparams.SyncCommitteeBranchDepth)
-	res[0] = []byte("xyz")
-	return res
-}
-
-// When the update has finality
-func createNonEmptyFinalityBranch() [][]byte {
-	res := make([][]byte, lightclient.FinalityBranchNumOfLeaves)
-	res[0] = []byte("xyz")
-	return res
-}
-
-func TestIsBetterUpdate(t *testing.T) {
-	testCases := []struct {
-		name           string
-		oldUpdate      *ethpbv2.LightClientUpdate
-		newUpdate      *ethpbv2.LightClientUpdate
-		expectedResult bool
-	}{
-		{
-			name: "new has supermajority but old doesn't",
-			oldUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b01111100, 0b1}, // [0,0,1,1,1,1,1,0]
-				},
-			},
-			newUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b11111100, 0b1}, // [0,0,1,1,1,1,1,1]
-				},
-			},
-			expectedResult: true,
-		},
-		{
-			name: "old has supermajority but new doesn't",
-			oldUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b11111100, 0b1}, // [0,0,1,1,1,1,1,1]
-				},
-			},
-			newUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b01111100, 0b1}, // [0,0,1,1,1,1,1,0]
-				},
-			},
-			expectedResult: false,
-		},
-		{
-			name: "new doesn't have supermajority and newNumActiveParticipants is greater than oldNumActiveParticipants",
-			oldUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b00111100, 0b1}, // [0,0,1,1,1,1,0,0]
-				},
-			},
-			newUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b01111100, 0b1}, // [0,0,1,1,1,1,1,0]
-				},
-			},
-			expectedResult: true,
-		},
-		{
-			name: "new doesn't have supermajority and newNumActiveParticipants is lesser than oldNumActiveParticipants",
-			oldUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b01111100, 0b1}, // [0,0,1,1,1,1,1,0]
-				},
-			},
-			newUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b00111100, 0b1}, // [0,0,1,1,1,1,0,0]
-				},
-			},
-			expectedResult: false,
-		},
-		{
-			name: "new has relevant sync committee but old doesn't",
-			oldUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b00111100, 0b1}, // [0,0,1,1,1,1,0,0]
-				},
-				AttestedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 1000000,
-						}},
-					},
-				},
-				NextSyncCommitteeBranch: make([][]byte, fieldparams.SyncCommitteeBranchDepth),
-				SignatureSlot:           9999,
-			},
-			newUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b00111100, 0b1}, // [0,0,1,1,1,1,0,0]
-				},
-				AttestedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 1000001,
-						}},
-					},
-				},
-				NextSyncCommitteeBranch: createNonEmptySyncCommitteeBranch(),
-				SignatureSlot:           1000000,
-			},
-			expectedResult: true,
-		},
-		{
-			name: "old has relevant sync committee but new doesn't",
-			oldUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b00111100, 0b1}, // [0,0,1,1,1,1,0,0]
-				},
-				AttestedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 1000001,
-						}},
-					},
-				},
-				NextSyncCommitteeBranch: createNonEmptySyncCommitteeBranch(),
-				SignatureSlot:           1000000,
-			},
-			newUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b00111100, 0b1}, // [0,0,1,1,1,1,0,0]
-				},
-				AttestedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 1000000,
-						}},
-					},
-				},
-				NextSyncCommitteeBranch: make([][]byte, fieldparams.SyncCommitteeBranchDepth),
-				SignatureSlot:           9999,
-			},
-			expectedResult: false,
-		},
-		{
-			name: "new has finality but old doesn't",
-			oldUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b00111100, 0b1}, // [0,0,1,1,1,1,0,0]
-				},
-				AttestedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 1000000,
-						}},
-					},
-				},
-				NextSyncCommitteeBranch: createNonEmptySyncCommitteeBranch(),
-				SignatureSlot:           9999,
-				FinalityBranch:          make([][]byte, lightclient.FinalityBranchNumOfLeaves),
-			},
-			newUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b00111100, 0b1}, // [0,0,1,1,1,1,0,0]
-				},
-				AttestedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 1000000,
-						}},
-					},
-				},
-				NextSyncCommitteeBranch: createNonEmptySyncCommitteeBranch(),
-				SignatureSlot:           9999,
-				FinalityBranch:          createNonEmptyFinalityBranch(),
-			},
-			expectedResult: true,
-		},
-		{
-			name: "old has finality but new doesn't",
-			oldUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b00111100, 0b1}, // [0,0,1,1,1,1,0,0]
-				},
-				AttestedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 1000000,
-						}},
-					},
-				},
-				NextSyncCommitteeBranch: createNonEmptySyncCommitteeBranch(),
-				SignatureSlot:           9999,
-				FinalityBranch:          createNonEmptyFinalityBranch(),
-			},
-			newUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b00111100, 0b1}, // [0,0,1,1,1,1,0,0]
-				},
-				AttestedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 1000000,
-						}},
-					},
-				},
-				NextSyncCommitteeBranch: createNonEmptySyncCommitteeBranch(),
-				SignatureSlot:           9999,
-				FinalityBranch:          make([][]byte, lightclient.FinalityBranchNumOfLeaves),
-			},
-			expectedResult: false,
-		},
-		{
-			name: "new has finality and sync committee finality both but old doesn't have sync committee finality",
-			oldUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b00111100, 0b1}, // [0,0,1,1,1,1,0,0]
-				},
-				AttestedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 1000000,
-						}},
-					},
-				},
-				NextSyncCommitteeBranch: createNonEmptySyncCommitteeBranch(),
-				SignatureSlot:           9999,
-				FinalityBranch:          createNonEmptyFinalityBranch(),
-				FinalizedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 9999,
-						}},
-					},
-				},
-			},
-			newUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b00111100, 0b1}, // [0,0,1,1,1,1,0,0]
-				},
-				AttestedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 1000000,
-						}},
-					},
-				},
-				NextSyncCommitteeBranch: createNonEmptySyncCommitteeBranch(),
-				SignatureSlot:           999999,
-				FinalityBranch:          createNonEmptyFinalityBranch(),
-				FinalizedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 999999,
-						}},
-					},
-				},
-			},
-			expectedResult: true,
-		},
-		{
-			name: "new has finality but doesn't have sync committee finality and old has sync committee finality",
-			oldUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b00111100, 0b1}, // [0,0,1,1,1,1,0,0]
-				},
-				AttestedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 1000000,
-						}},
-					},
-				},
-				NextSyncCommitteeBranch: createNonEmptySyncCommitteeBranch(),
-				SignatureSlot:           999999,
-				FinalityBranch:          createNonEmptyFinalityBranch(),
-				FinalizedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 999999,
-						}},
-					},
-				},
-			},
-			newUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b00111100, 0b1}, // [0,0,1,1,1,1,0,0]
-				},
-				AttestedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 1000000,
-						}},
-					},
-				},
-				NextSyncCommitteeBranch: createNonEmptySyncCommitteeBranch(),
-				SignatureSlot:           9999,
-				FinalityBranch:          createNonEmptyFinalityBranch(),
-				FinalizedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 9999,
-						}},
-					},
-				},
-			},
-			expectedResult: false,
-		},
-		{
-			name: "new has more active participants than old",
-			oldUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b00111100, 0b1}, // [0,0,1,1,1,1,0,0]
-				},
-				AttestedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 1000000,
-						}},
-					},
-				},
-				NextSyncCommitteeBranch: createNonEmptySyncCommitteeBranch(),
-				SignatureSlot:           9999,
-				FinalityBranch:          createNonEmptyFinalityBranch(),
-				FinalizedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 9999,
-						}},
-					},
-				},
-			},
-			newUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b01111100, 0b1}, // [0,1,1,1,1,1,0,0]
-				},
-				AttestedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 1000000,
-						}},
-					},
-				},
-				NextSyncCommitteeBranch: createNonEmptySyncCommitteeBranch(),
-				SignatureSlot:           9999,
-				FinalityBranch:          createNonEmptyFinalityBranch(),
-				FinalizedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 9999,
-						}},
-					},
-				},
-			},
-			expectedResult: true,
-		},
-		{
-			name: "new has less active participants than old",
-			oldUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b01111100, 0b1}, // [0,1,1,1,1,1,0,0]
-				},
-				AttestedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 1000000,
-						}},
-					},
-				},
-				NextSyncCommitteeBranch: createNonEmptySyncCommitteeBranch(),
-				SignatureSlot:           9999,
-				FinalityBranch:          createNonEmptyFinalityBranch(),
-				FinalizedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 9999,
-						}},
-					},
-				},
-			},
-			newUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b00111100, 0b1}, // [0,0,1,1,1,1,0,0]
-				},
-				AttestedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 1000000,
-						}},
-					},
-				},
-				NextSyncCommitteeBranch: createNonEmptySyncCommitteeBranch(),
-				SignatureSlot:           9999,
-				FinalityBranch:          createNonEmptyFinalityBranch(),
-				FinalizedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 9999,
-						}},
-					},
-				},
-			},
-			expectedResult: false,
-		},
-		{
-			name: "new's attested header's slot is lesser than old's attested header's slot",
-			oldUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b00111100, 0b1}, // [0,0,1,1,1,1,0,0]
-				},
-				AttestedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 1000000,
-						}},
-					},
-				},
-				NextSyncCommitteeBranch: createNonEmptySyncCommitteeBranch(),
-				SignatureSlot:           9999,
-				FinalityBranch:          createNonEmptyFinalityBranch(),
-				FinalizedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 9999,
-						}},
-					},
-				},
-			},
-			newUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b00111100, 0b1}, // [0,0,1,1,1,1,0,0]
-				},
-				AttestedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 999999,
-						}},
-					},
-				},
-				NextSyncCommitteeBranch: createNonEmptySyncCommitteeBranch(),
-				SignatureSlot:           9999,
-				FinalityBranch:          createNonEmptyFinalityBranch(),
-				FinalizedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 9999,
-						}},
-					},
-				},
-			},
-			expectedResult: true,
-		},
-		{
-			name: "new's attested header's slot is greater than old's attested header's slot",
-			oldUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b00111100, 0b1}, // [0,0,1,1,1,1,0,0]
-				},
-				AttestedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 999999,
-						}},
-					},
-				},
-				NextSyncCommitteeBranch: createNonEmptySyncCommitteeBranch(),
-				SignatureSlot:           9999,
-				FinalityBranch:          createNonEmptyFinalityBranch(),
-				FinalizedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 9999,
-						}},
-					},
-				},
-			},
-			newUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b00111100, 0b1}, // [0,0,1,1,1,1,0,0]
-				},
-				AttestedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 1000000,
-						}},
-					},
-				},
-				NextSyncCommitteeBranch: createNonEmptySyncCommitteeBranch(),
-				SignatureSlot:           9999,
-				FinalityBranch:          createNonEmptyFinalityBranch(),
-				FinalizedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 9999,
-						}},
-					},
-				},
-			},
-			expectedResult: false,
-		},
-		{
-			name: "none of the above conditions are met and new signature's slot is less than old signature's slot",
-			oldUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b00111100, 0b1}, // [0,0,1,1,1,1,0,0]
-				},
-				AttestedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 1000000,
-						}},
-					},
-				},
-				NextSyncCommitteeBranch: createNonEmptySyncCommitteeBranch(),
-				SignatureSlot:           9999,
-				FinalityBranch:          createNonEmptyFinalityBranch(),
-				FinalizedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 9999,
-						}},
-					},
-				},
-			},
-			newUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b00111100, 0b1}, // [0,0,1,1,1,1,0,0]
-				},
-				AttestedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 1000000,
-						}},
-					},
-				},
-				NextSyncCommitteeBranch: createNonEmptySyncCommitteeBranch(),
-				SignatureSlot:           9998,
-				FinalityBranch:          createNonEmptyFinalityBranch(),
-				FinalizedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 9999,
-						}},
-					},
-				},
-			},
-			expectedResult: true,
-		},
-		{
-			name: "none of the above conditions are met and new signature's slot is greater than old signature's slot",
-			oldUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b00111100, 0b1}, // [0,0,1,1,1,1,0,0]
-				},
-				AttestedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 1000000,
-						}},
-					},
-				},
-				NextSyncCommitteeBranch: createNonEmptySyncCommitteeBranch(),
-				SignatureSlot:           9998,
-				FinalityBranch:          createNonEmptyFinalityBranch(),
-				FinalizedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 9999,
-						}},
-					},
-				},
-			},
-			newUpdate: &ethpbv2.LightClientUpdate{
-				SyncAggregate: &ethpbv1.SyncAggregate{
-					SyncCommitteeBits: []byte{0b00111100, 0b1}, // [0,0,1,1,1,1,0,0]
-				},
-				AttestedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 1000000,
-						}},
-					},
-				},
-				NextSyncCommitteeBranch: createNonEmptySyncCommitteeBranch(),
-				SignatureSlot:           9999,
-				FinalityBranch:          createNonEmptyFinalityBranch(),
-				FinalizedHeader: &ethpbv2.LightClientHeaderContainer{
-					Header: &ethpbv2.LightClientHeaderContainer_HeaderAltair{
-						HeaderAltair: &ethpbv2.LightClientHeader{Beacon: &ethpbv1.BeaconBlockHeader{
-							Slot: 9999,
-						}},
-					},
-				},
-			},
-			expectedResult: false,
-		},
-	}
-
-	for _, testCase := range testCases {
-		t.Run(testCase.name, func(t *testing.T) {
-			result, err := IsBetterUpdate(testCase.newUpdate, testCase.oldUpdate)
-			assert.NoError(t, err)
-			assert.Equal(t, testCase.expectedResult, result)
-		})
-	}
-}

beacon-chain/rpc/eth/light-client/server.go

@@ -7,8 +7,9 @@ import (
 )
 
 type Server struct {
-	Blocker     lookup.Blocker
-	Stater      lookup.Stater
-	HeadFetcher blockchain.HeadFetcher
-	BeaconDB    db.HeadAccessDatabase
+	Blocker          lookup.Blocker
+	Stater           lookup.Stater
+	HeadFetcher      blockchain.HeadFetcher
+	ChainInfoFetcher blockchain.ChainInfoFetcher
+	BeaconDB         db.HeadAccessDatabase
 }

beacon-chain/rpc/metrics.go

@@ -0,0 +1,31 @@
+package rpc
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+)
+
+var (
+	httpRequestLatency = promauto.NewHistogramVec(
+		prometheus.HistogramOpts{
+			Name:    "http_request_latency_seconds",
+			Help:    "Latency of HTTP requests in seconds",
+			Buckets: []float64{0.001, 0.01, 0.025, 0.1, 0.25, 1, 2.5, 10},
+		},
+		[]string{"endpoint", "code", "method"},
+	)
+	httpRequestCount = promauto.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "http_request_count",
+			Help: "Number of HTTP requests",
+		},
+		[]string{"endpoint", "code", "method"},
+	)
+	httpErrorCount = promauto.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "http_error_count",
+			Help: "Total HTTP errors for beacon node requests",
+		},
+		[]string{"endpoint", "code", "method"},
+	)
+)

beacon-chain/rpc/prysm/v1alpha1/beacon/attestations.go

@@ -303,7 +303,7 @@ func (bs *Server) ListIndexedAttestationsElectra(
 // that it was included in a block. The attestation may have expired.
 // Refer to the ethereum consensus specification for more details on how
 // attestations are processed and when they are no longer valid.
-// https://github.com/ethereum/consensus-specs/blob/dev/specs/core/0_beacon-chain.md#attestations
+// https://github.com/ethereum/consensus-specs/blob/dev/specs/phase0/beacon-chain.md#attestations
 func (bs *Server) AttestationPool(_ context.Context, req *ethpb.AttestationPoolRequest) (*ethpb.AttestationPoolResponse, error) {
 	atts, err := attestationsFromPool[*ethpb.Attestation](req.PageSize, bs.AttestationsPool)
 	if err != nil {

beacon-chain/rpc/prysm/v1alpha1/beacon/attestations_test.go

@@ -765,6 +765,8 @@ func TestServer_ListIndexedAttestationsElectra(t *testing.T) {
 		cb := primitives.NewAttestationCommitteeBits()
 		cb.SetBitAt(0, true)
 		blockExample := util.NewBeaconBlockElectra()
+		ab := bitfield.NewBitlist(128 / uint64(params.BeaconConfig().SlotsPerEpoch))
+		ab.SetBitAt(0, true)
 		blockExample.Block.Body.Attestations = []*ethpb.AttestationElectra{
 			{
 				Signature: make([]byte, fieldparams.BLSSignatureLength),
@@ -778,7 +780,7 @@ func TestServer_ListIndexedAttestationsElectra(t *testing.T) {
 					},
 					Slot: i,
 				},
-				AggregationBits: bitfield.NewBitlist(128 / uint64(params.BeaconConfig().SlotsPerEpoch)),
+				AggregationBits: ab,
 				CommitteeBits:   cb,
 			},
 		}

beacon-chain/rpc/prysm/v1alpha1/validator/proposer.go

@@ -99,14 +99,18 @@ func (vs *Server) GetBeaconBlock(ctx context.Context, req *ethpb.BlockRequest) (
 	}
 
 	resp, err := vs.BuildBlockParallel(ctx, sBlk, head, req.SkipMevBoost, builderBoostFactor)
-	log.WithFields(logrus.Fields{
+	log := log.WithFields(logrus.Fields{
 		"slot":               req.Slot,
 		"sinceSlotStartTime": time.Since(t),
 		"validator":          sBlk.Block().ProposerIndex(),
-	}).Info("Finished building block")
+	})
+
 	if err != nil {
+		log.WithError(err).Error("Finished building block")
 		return nil, errors.Wrap(err, "could not build block in parallel")
 	}
+
+	log.Info("Finished building block")
 	return resp, nil
 }
 
@@ -236,7 +240,12 @@ func (vs *Server) BuildBlockParallel(ctx context.Context, sBlk interfaces.Signed
 		// There's no reason to try to get a builder bid if local override is true.
 		var builderBid builderapi.Bid
 		if !(local.OverrideBuilder || skipMevBoost) {
-			builderBid, err = vs.getBuilderPayloadAndBlobs(ctx, sBlk.Block().Slot(), sBlk.Block().ProposerIndex())
+			latestHeader, err := head.LatestExecutionPayloadHeader()
+			if err != nil {
+				return nil, status.Errorf(codes.Internal, "Could not get latest execution payload header: %v", err)
+			}
+			parentGasLimit := latestHeader.GasLimit()
+			builderBid, err = vs.getBuilderPayloadAndBlobs(ctx, sBlk.Block().Slot(), sBlk.Block().ProposerIndex(), parentGasLimit)
 			if err != nil {
 				builderGetPayloadMissCount.Inc()
 				log.WithError(err).Error("Could not get builder payload")

beacon-chain/rpc/prysm/v1alpha1/validator/proposer_bellatrix.go

@@ -51,6 +51,7 @@ var emptyTransactionsRoot = [32]byte{127, 254, 36, 30, 166, 1, 135, 253, 176, 24
 // blockBuilderTimeout is the maximum amount of time allowed for a block builder to respond to a
 // block request. This value is known as `BUILDER_PROPOSAL_DELAY_TOLERANCE` in builder spec.
 const blockBuilderTimeout = 1 * time.Second
+const gasLimitAdjustmentFactor = 1024
 
 // Sets the execution data for the block. Execution data can come from local EL client or remote builder depends on validator registration and circuit breaker conditions.
 func setExecutionData(ctx context.Context, blk interfaces.SignedBeaconBlock, local *blocks.GetPayloadResponse, bid builder.Bid, builderBoostFactor primitives.Gwei) (primitives.Wei, *enginev1.BlobsBundle, error) {
@@ -170,7 +171,11 @@ func setExecutionData(ctx context.Context, blk interfaces.SignedBeaconBlock, loc
 
 // This function retrieves the payload header and kzg commitments given the slot number and the validator index.
 // It's a no-op if the latest head block is not versioned bellatrix.
-func (vs *Server) getPayloadHeaderFromBuilder(ctx context.Context, slot primitives.Slot, idx primitives.ValidatorIndex) (builder.Bid, error) {
+func (vs *Server) getPayloadHeaderFromBuilder(
+	ctx context.Context,
+	slot primitives.Slot,
+	idx primitives.ValidatorIndex,
+	parentGasLimit uint64) (builder.Bid, error) {
 	ctx, span := trace.StartSpan(ctx, "ProposerServer.getPayloadHeaderFromBuilder")
 	defer span.End()
 
@@ -247,8 +252,9 @@ func (vs *Server) getPayloadHeaderFromBuilder(ctx context.Context, slot primitiv
 	if err != nil {
 		log.WithError(err).Warn("Proposer: failed to get registration by validator ID, could not check gas limit")
 	} else {
-		if reg.GasLimit != header.GasLimit() {
-			return nil, fmt.Errorf("incorrect header gas limit %d != %d", reg.GasLimit, header.GasLimit())
+		gasLimit := expectedGasLimit(parentGasLimit, reg.GasLimit)
+		if gasLimit != header.GasLimit() {
+			return nil, fmt.Errorf("incorrect header gas limit %d != %d", gasLimit, header.GasLimit())
 		}
 	}
 
@@ -402,3 +408,32 @@ func setExecution(blk interfaces.SignedBeaconBlock, execution interfaces.Executi
 
 	return nil
 }
+
+// Calculates expected gas limit based on parent gas limit and target gas limit.
+// Spec code:
+//
+//	def expected_gas_limit(parent_gas_limit, target_gas_limit, adjustment_factor):
+//	 max_gas_limit_difference = (parent_gas_limit // adjustment_factor) - 1
+//	 if target_gas_limit > parent_gas_limit:
+//	     gas_diff = target_gas_limit - parent_gas_limit
+//	     return parent_gas_limit + min(gas_diff, max_gas_limit_difference)
+//	 else:
+//	     gas_diff = parent_gas_limit - target_gas_limit
+//	     return parent_gas_limit - min(gas_diff, max_gas_limit_difference)
+func expectedGasLimit(parentGasLimit, proposerGasLimit uint64) uint64 {
+	maxGasLimitDiff := uint64(0)
+	if parentGasLimit > gasLimitAdjustmentFactor {
+		maxGasLimitDiff = parentGasLimit/gasLimitAdjustmentFactor - 1
+	}
+	if proposerGasLimit > parentGasLimit {
+		if proposerGasLimit-parentGasLimit > maxGasLimitDiff {
+			return parentGasLimit + maxGasLimitDiff
+		}
+		return proposerGasLimit
+	}
+
+	if parentGasLimit-proposerGasLimit > maxGasLimitDiff {
+		return parentGasLimit - maxGasLimitDiff
+	}
+	return proposerGasLimit
+}

beacon-chain/rpc/prysm/v1alpha1/validator/proposer_bellatrix_test.go

@@ -94,14 +94,14 @@ func TestServer_setExecutionData(t *testing.T) {
 		ForkchoiceFetcher:      &blockchainTest.ChainService{},
 		TrackedValidatorsCache: cache.NewTrackedValidatorsCache(),
 	}
-
+	gasLimit := uint64(30000000)
 	t.Run("No builder configured. Use local block", func(t *testing.T) {
 		blk, err := blocks.NewSignedBeaconBlock(util.NewBeaconBlockCapella())
 		require.NoError(t, err)
 		b := blk.Block()
 		res, err := vs.getLocalPayload(ctx, b, capellaTransitionState)
 		require.NoError(t, err)
-		builderBid, err := vs.getBuilderPayloadAndBlobs(ctx, b.Slot(), b.ProposerIndex())
+		builderBid, err := vs.getBuilderPayloadAndBlobs(ctx, b.Slot(), b.ProposerIndex(), gasLimit)
 		require.NoError(t, err)
 		require.IsNil(t, builderBid)
 		_, bundle, err := setExecutionData(context.Background(), blk, res, builderBid, defaultBuilderBoostFactor)
@@ -115,7 +115,11 @@ func TestServer_setExecutionData(t *testing.T) {
 		blk, err := blocks.NewSignedBeaconBlock(util.NewBeaconBlockCapella())
 		require.NoError(t, err)
 		require.NoError(t, vs.BeaconDB.SaveRegistrationsByValidatorIDs(ctx, []primitives.ValidatorIndex{blk.Block().ProposerIndex()},
-			[]*ethpb.ValidatorRegistrationV1{{FeeRecipient: make([]byte, fieldparams.FeeRecipientLength), Timestamp: uint64(time.Now().Unix()), Pubkey: make([]byte, fieldparams.BLSPubkeyLength)}}))
+			[]*ethpb.ValidatorRegistrationV1{{
+				FeeRecipient: make([]byte, fieldparams.FeeRecipientLength),
+				Timestamp:    uint64(time.Now().Unix()),
+				GasLimit:     gasLimit,
+				Pubkey:       make([]byte, fieldparams.BLSPubkeyLength)}}))
 		ti, err := slots.ToTime(uint64(time.Now().Unix()), 0)
 		require.NoError(t, err)
 		sk, err := bls.RandKey()
@@ -135,6 +139,7 @@ func TestServer_setExecutionData(t *testing.T) {
 				BlockHash:        make([]byte, fieldparams.RootLength),
 				TransactionsRoot: bytesutil.PadTo([]byte{1}, fieldparams.RootLength),
 				WithdrawalsRoot:  make([]byte, fieldparams.RootLength),
+				GasLimit:         gasLimit,
 			},
 			Pubkey: sk.PublicKey().Marshal(),
 			Value:  bytesutil.PadTo([]byte{1}, 32),
@@ -164,7 +169,7 @@ func TestServer_setExecutionData(t *testing.T) {
 
 		res, err := vs.getLocalPayload(ctx, b, capellaTransitionState)
 		require.NoError(t, err)
-		builderBid, err := vs.getBuilderPayloadAndBlobs(ctx, b.Slot(), b.ProposerIndex())
+		builderBid, err := vs.getBuilderPayloadAndBlobs(ctx, b.Slot(), b.ProposerIndex(), gasLimit)
 		require.NoError(t, err)
 		_, err = builderBid.Header()
 		require.NoError(t, err)
@@ -184,7 +189,11 @@ func TestServer_setExecutionData(t *testing.T) {
 		blk, err := blocks.NewSignedBeaconBlock(util.NewBlindedBeaconBlockCapella())
 		require.NoError(t, err)
 		require.NoError(t, vs.BeaconDB.SaveRegistrationsByValidatorIDs(ctx, []primitives.ValidatorIndex{blk.Block().ProposerIndex()},
-			[]*ethpb.ValidatorRegistrationV1{{FeeRecipient: make([]byte, fieldparams.FeeRecipientLength), Timestamp: uint64(time.Now().Unix()), Pubkey: make([]byte, fieldparams.BLSPubkeyLength)}}))
+			[]*ethpb.ValidatorRegistrationV1{{
+				FeeRecipient: make([]byte, fieldparams.FeeRecipientLength),
+				Timestamp:    uint64(time.Now().Unix()),
+				GasLimit:     gasLimit,
+				Pubkey:       make([]byte, fieldparams.BLSPubkeyLength)}}))
 		ti, err := slots.ToTime(uint64(time.Now().Unix()), 0)
 		require.NoError(t, err)
 		sk, err := bls.RandKey()
@@ -207,6 +216,7 @@ func TestServer_setExecutionData(t *testing.T) {
 				BlockHash:        make([]byte, fieldparams.RootLength),
 				TransactionsRoot: bytesutil.PadTo([]byte{1}, fieldparams.RootLength),
 				WithdrawalsRoot:  wr[:],
+				GasLimit:         gasLimit,
 			},
 			Pubkey: sk.PublicKey().Marshal(),
 			Value:  bytesutil.PadTo(builderValue, 32),
@@ -236,7 +246,7 @@ func TestServer_setExecutionData(t *testing.T) {
 		b := blk.Block()
 		res, err := vs.getLocalPayload(ctx, b, capellaTransitionState)
 		require.NoError(t, err)
-		builderBid, err := vs.getBuilderPayloadAndBlobs(ctx, b.Slot(), b.ProposerIndex())
+		builderBid, err := vs.getBuilderPayloadAndBlobs(ctx, b.Slot(), b.ProposerIndex(), gasLimit)
 		require.NoError(t, err)
 		_, err = builderBid.Header()
 		require.NoError(t, err)
@@ -256,7 +266,11 @@ func TestServer_setExecutionData(t *testing.T) {
 		blk, err := blocks.NewSignedBeaconBlock(util.NewBlindedBeaconBlockCapella())
 		require.NoError(t, err)
 		require.NoError(t, vs.BeaconDB.SaveRegistrationsByValidatorIDs(ctx, []primitives.ValidatorIndex{blk.Block().ProposerIndex()},
-			[]*ethpb.ValidatorRegistrationV1{{FeeRecipient: make([]byte, fieldparams.FeeRecipientLength), Timestamp: uint64(time.Now().Unix()), Pubkey: make([]byte, fieldparams.BLSPubkeyLength)}}))
+			[]*ethpb.ValidatorRegistrationV1{{
+				FeeRecipient: make([]byte, fieldparams.FeeRecipientLength),
+				Timestamp:    uint64(time.Now().Unix()),
+				GasLimit:     gasLimit,
+				Pubkey:       make([]byte, fieldparams.BLSPubkeyLength)}}))
 		ti, err := slots.ToTime(uint64(time.Now().Unix()), 0)
 		require.NoError(t, err)
 		sk, err := bls.RandKey()
@@ -278,6 +292,7 @@ func TestServer_setExecutionData(t *testing.T) {
 				Timestamp:        uint64(ti.Unix()),
 				BlockNumber:      2,
 				WithdrawalsRoot:  wr[:],
+				GasLimit:         gasLimit,
 			},
 			Pubkey: sk.PublicKey().Marshal(),
 			Value:  bytesutil.PadTo(builderValue, 32),
@@ -307,7 +322,7 @@ func TestServer_setExecutionData(t *testing.T) {
 		b := blk.Block()
 		res, err := vs.getLocalPayload(ctx, b, capellaTransitionState)
 		require.NoError(t, err)
-		builderBid, err := vs.getBuilderPayloadAndBlobs(ctx, b.Slot(), b.ProposerIndex())
+		builderBid, err := vs.getBuilderPayloadAndBlobs(ctx, b.Slot(), b.ProposerIndex(), gasLimit)
 		require.NoError(t, err)
 		_, err = builderBid.Header()
 		require.NoError(t, err)
@@ -327,7 +342,11 @@ func TestServer_setExecutionData(t *testing.T) {
 		blk, err := blocks.NewSignedBeaconBlock(util.NewBlindedBeaconBlockCapella())
 		require.NoError(t, err)
 		require.NoError(t, vs.BeaconDB.SaveRegistrationsByValidatorIDs(ctx, []primitives.ValidatorIndex{blk.Block().ProposerIndex()},
-			[]*ethpb.ValidatorRegistrationV1{{FeeRecipient: make([]byte, fieldparams.FeeRecipientLength), Timestamp: uint64(time.Now().Unix()), Pubkey: make([]byte, fieldparams.BLSPubkeyLength)}}))
+			[]*ethpb.ValidatorRegistrationV1{{
+				FeeRecipient: make([]byte, fieldparams.FeeRecipientLength),
+				Timestamp:    uint64(time.Now().Unix()),
+				GasLimit:     gasLimit,
+				Pubkey:       make([]byte, fieldparams.BLSPubkeyLength)}}))
 		ti, err := slots.ToTime(uint64(time.Now().Unix()), 0)
 		require.NoError(t, err)
 		sk, err := bls.RandKey()
@@ -349,6 +368,7 @@ func TestServer_setExecutionData(t *testing.T) {
 				Timestamp:        uint64(ti.Unix()),
 				BlockNumber:      2,
 				WithdrawalsRoot:  wr[:],
+				GasLimit:         gasLimit,
 			},
 			Pubkey: sk.PublicKey().Marshal(),
 			Value:  bytesutil.PadTo(builderValue, 32),
@@ -378,7 +398,7 @@ func TestServer_setExecutionData(t *testing.T) {
 		b := blk.Block()
 		res, err := vs.getLocalPayload(ctx, b, capellaTransitionState)
 		require.NoError(t, err)
-		builderBid, err := vs.getBuilderPayloadAndBlobs(ctx, b.Slot(), b.ProposerIndex())
+		builderBid, err := vs.getBuilderPayloadAndBlobs(ctx, b.Slot(), b.ProposerIndex(), gasLimit)
 		require.NoError(t, err)
 		_, err = builderBid.Header()
 		require.NoError(t, err)
@@ -404,7 +424,7 @@ func TestServer_setExecutionData(t *testing.T) {
 		b := blk.Block()
 		res, err := vs.getLocalPayload(ctx, b, capellaTransitionState)
 		require.NoError(t, err)
-		builderBid, err := vs.getBuilderPayloadAndBlobs(ctx, b.Slot(), b.ProposerIndex())
+		builderBid, err := vs.getBuilderPayloadAndBlobs(ctx, b.Slot(), b.ProposerIndex(), gasLimit)
 		require.NoError(t, err)
 		_, err = builderBid.Header()
 		require.NoError(t, err)
@@ -436,7 +456,7 @@ func TestServer_setExecutionData(t *testing.T) {
 		b := blk.Block()
 		res, err := vs.getLocalPayload(ctx, b, capellaTransitionState)
 		require.NoError(t, err)
-		builderBid, err := vs.getBuilderPayloadAndBlobs(ctx, b.Slot(), b.ProposerIndex())
+		builderBid, err := vs.getBuilderPayloadAndBlobs(ctx, b.Slot(), b.ProposerIndex(), gasLimit)
 		require.NoError(t, err)
 		_, err = builderBid.Header()
 		require.NoError(t, err)
@@ -471,7 +491,7 @@ func TestServer_setExecutionData(t *testing.T) {
 		b := blk.Block()
 		res, err := vs.getLocalPayload(ctx, b, capellaTransitionState)
 		require.NoError(t, err)
-		builderBid, err := vs.getBuilderPayloadAndBlobs(ctx, b.Slot(), b.ProposerIndex())
+		builderBid, err := vs.getBuilderPayloadAndBlobs(ctx, b.Slot(), b.ProposerIndex(), gasLimit)
 		require.NoError(t, err)
 		builderKzgCommitments, err := builderBid.BlobKzgCommitments()
 		if builderBid.Version() >= version.Deneb {
@@ -503,7 +523,7 @@ func TestServer_setExecutionData(t *testing.T) {
 		b := blk.Block()
 		res, err := vs.getLocalPayload(ctx, b, capellaTransitionState)
 		require.NoError(t, err)
-		builderBid, err := vs.getBuilderPayloadAndBlobs(ctx, b.Slot(), b.ProposerIndex())
+		builderBid, err := vs.getBuilderPayloadAndBlobs(ctx, b.Slot(), b.ProposerIndex(), gasLimit)
 		require.ErrorIs(t, consensus_types.ErrNilObjectWrapped, err) // Builder returns fault. Use local block
 		require.IsNil(t, builderBid)
 		_, bundle, err := setExecutionData(context.Background(), blk, res, nil, defaultBuilderBoostFactor)
@@ -578,6 +598,7 @@ func TestServer_setExecutionData(t *testing.T) {
 				WithdrawalsRoot:  wr[:],
 				BlobGasUsed:      123,
 				ExcessBlobGas:    456,
+				GasLimit:         gasLimit,
 			},
 			Pubkey:             sk.PublicKey().Marshal(),
 			Value:              bytesutil.PadTo(builderValue, 32),
@@ -599,7 +620,11 @@ func TestServer_setExecutionData(t *testing.T) {
 			Cfg:           &builderTest.Config{BeaconDB: beaconDB},
 		}
 		require.NoError(t, beaconDB.SaveRegistrationsByValidatorIDs(ctx, []primitives.ValidatorIndex{blk.Block().ProposerIndex()},
-			[]*ethpb.ValidatorRegistrationV1{{FeeRecipient: make([]byte, fieldparams.FeeRecipientLength), Timestamp: uint64(time.Now().Unix()), Pubkey: make([]byte, fieldparams.BLSPubkeyLength)}}))
+			[]*ethpb.ValidatorRegistrationV1{{
+				FeeRecipient: make([]byte, fieldparams.FeeRecipientLength),
+				Timestamp:    uint64(time.Now().Unix()),
+				GasLimit:     gasLimit,
+				Pubkey:       make([]byte, fieldparams.BLSPubkeyLength)}}))
 
 		wb, err := blocks.NewSignedBeaconBlock(util.NewBeaconBlockDeneb())
 		require.NoError(t, err)
@@ -619,7 +644,7 @@ func TestServer_setExecutionData(t *testing.T) {
 		require.NoError(t, err)
 		blk.SetSlot(primitives.Slot(params.BeaconConfig().DenebForkEpoch) * params.BeaconConfig().SlotsPerEpoch)
 		require.NoError(t, err)
-		builderBid, err := vs.getBuilderPayloadAndBlobs(ctx, blk.Block().Slot(), blk.Block().ProposerIndex())
+		builderBid, err := vs.getBuilderPayloadAndBlobs(ctx, blk.Block().Slot(), blk.Block().ProposerIndex(), gasLimit)
 		require.NoError(t, err)
 		builderPayload, err := builderBid.Header()
 		require.NoError(t, err)
@@ -660,6 +685,8 @@ func TestServer_getPayloadHeader(t *testing.T) {
 
 	sk, err := bls.RandKey()
 	require.NoError(t, err)
+
+	gasLimit := uint64(30000000)
 	bid := &ethpb.BuilderBid{
 		Header: &v1.ExecutionPayloadHeader{
 			FeeRecipient:     make([]byte, fieldparams.FeeRecipientLength),
@@ -672,6 +699,7 @@ func TestServer_getPayloadHeader(t *testing.T) {
 			TransactionsRoot: bytesutil.PadTo([]byte{1}, fieldparams.RootLength),
 			ParentHash:       params.BeaconConfig().ZeroHash[:],
 			Timestamp:        uint64(ti.Unix()),
+			GasLimit:         gasLimit,
 		},
 		Pubkey: sk.PublicKey().Marshal(),
 		Value:  bytesutil.PadTo([]byte{1, 2, 3}, 32),
@@ -709,6 +737,7 @@ func TestServer_getPayloadHeader(t *testing.T) {
 			ParentHash:       params.BeaconConfig().ZeroHash[:],
 			Timestamp:        uint64(tiCapella.Unix()),
 			WithdrawalsRoot:  wr[:],
+			GasLimit:         gasLimit,
 		},
 		Pubkey: sk.PublicKey().Marshal(),
 		Value:  bytesutil.PadTo([]byte{1, 2, 3}, 32),
@@ -732,7 +761,7 @@ func TestServer_getPayloadHeader(t *testing.T) {
 			TransactionsRoot: bytesutil.PadTo([]byte{1}, fieldparams.RootLength),
 			ParentHash:       params.BeaconConfig().ZeroHash[:],
 			Timestamp:        uint64(tiCapella.Unix()),
-			GasLimit:         100,
+			GasLimit:         31000000,
 		},
 		Pubkey: sk.PublicKey().Marshal(),
 		Value:  bytesutil.PadTo([]byte{1, 2, 3}, 32),
@@ -743,7 +772,6 @@ func TestServer_getPayloadHeader(t *testing.T) {
 			Signature: sk.Sign(srCapella[:]).Marshal(),
 		}
 
-	require.NoError(t, err)
 	tests := []struct {
 		name                  string
 		head                  interfaces.ReadOnlySignedBeaconBlock
@@ -855,21 +883,6 @@ func TestServer_getPayloadHeader(t *testing.T) {
 			},
 			err: "is different from head block version",
 		},
-		{
-			name: "incorrect gas limit",
-			mock: &builderTest.MockBuilderService{
-				Bid: signedIncorrectGasLimitBid,
-			},
-			fetcher: &blockchainTest.ChainService{
-				Block: func() interfaces.ReadOnlySignedBeaconBlock {
-					wb, err := blocks.NewSignedBeaconBlock(util.NewBeaconBlockBellatrix())
-					require.NoError(t, err)
-					wb.SetSlot(primitives.Slot(params.BeaconConfig().BellatrixForkEpoch) * params.BeaconConfig().SlotsPerEpoch)
-					return wb
-				}(),
-			},
-			err: "incorrect header gas limit 0 != 100",
-		},
 		{
 			name: "different bid version during hard fork",
 			mock: &builderTest.MockBuilderService{
@@ -885,6 +898,21 @@ func TestServer_getPayloadHeader(t *testing.T) {
 			},
 			returnedHeaderCapella: bidCapella.Header,
 		},
+		{
+			name: "incorrect gas limit",
+			mock: &builderTest.MockBuilderService{
+				Bid: signedIncorrectGasLimitBid,
+			},
+			fetcher: &blockchainTest.ChainService{
+				Block: func() interfaces.ReadOnlySignedBeaconBlock {
+					wb, err := blocks.NewSignedBeaconBlock(util.NewBeaconBlockBellatrix())
+					require.NoError(t, err)
+					wb.SetSlot(primitives.Slot(params.BeaconConfig().BellatrixForkEpoch) * params.BeaconConfig().SlotsPerEpoch)
+					return wb
+				}(),
+			},
+			err: "incorrect header gas limit 30000000 != 31000000",
+		},
 	}
 	for _, tc := range tests {
 		t.Run(tc.name, func(t *testing.T) {
@@ -894,7 +922,7 @@ func TestServer_getPayloadHeader(t *testing.T) {
 			regCache := cache.NewRegistrationCache()
 			regCache.UpdateIndexToRegisteredMap(context.Background(), map[primitives.ValidatorIndex]*ethpb.ValidatorRegistrationV1{
 				0: {
-					GasLimit:     0,
+					GasLimit:     gasLimit,
 					FeeRecipient: make([]byte, 20),
 					Pubkey:       make([]byte, 48),
 				},
@@ -902,7 +930,7 @@ func TestServer_getPayloadHeader(t *testing.T) {
 			tc.mock.RegistrationCache = regCache
 			hb, err := vs.HeadFetcher.HeadBlock(context.Background())
 			require.NoError(t, err)
-			bid, err := vs.getPayloadHeaderFromBuilder(context.Background(), hb.Block().Slot(), 0)
+			bid, err := vs.getPayloadHeaderFromBuilder(context.Background(), hb.Block().Slot(), 0, 30000000)
 			if tc.err != "" {
 				require.ErrorContains(t, tc.err, err)
 			} else {
@@ -1018,3 +1046,87 @@ func TestEmptyTransactionsRoot(t *testing.T) {
 	require.NoError(t, err)
 	require.DeepEqual(t, r, emptyTransactionsRoot)
 }
+
+func Test_expectedGasLimit(t *testing.T) {
+	type args struct {
+		parentGasLimit uint64
+		targetGasLimit uint64
+	}
+	tests := []struct {
+		name string
+		args args
+		want uint64
+	}{
+		{
+			name: "Increase within limit",
+			args: args{
+				parentGasLimit: 15000000,
+				targetGasLimit: 15000100,
+			},
+			want: 15000100,
+		},
+		{
+			name: "Increase exceeding limit",
+			args: args{
+				parentGasLimit: 15000000,
+				targetGasLimit: 16000000,
+			},
+			want: 15014647, // maxGasLimitDiff = (15000000 / 1024) - 1 = 1464
+		},
+		{
+			name: "Decrease within limit",
+			args: args{
+				parentGasLimit: 15000000,
+				targetGasLimit: 14999990,
+			},
+			want: 14999990,
+		},
+		{
+			name: "Decrease exceeding limit",
+			args: args{
+				parentGasLimit: 15000000,
+				targetGasLimit: 14000000,
+			},
+			want: 14985353, // maxGasLimitDiff = (15000000 / 1024) - 1 = 1464
+		},
+		{
+			name: "Target equals parent",
+			args: args{
+				parentGasLimit: 15000000,
+				targetGasLimit: 15000000,
+			},
+			want: 15000000, // No change
+		},
+		{
+			name: "Very small parent gas limit",
+			args: args{
+				parentGasLimit: 1025,
+				targetGasLimit: 2000,
+			},
+			want: 1025 + ((1025 / 1024) - 1),
+		},
+		{
+			name: "Target far below parent but limited",
+			args: args{
+				parentGasLimit: 20000000,
+				targetGasLimit: 10000000,
+			},
+			want: 19980470, // maxGasLimitDiff = (20000000 / 1024) - 1
+		},
+		{
+			name: "Parent gas limit under flows",
+			args: args{
+				parentGasLimit: 1023,
+				targetGasLimit: 30000000,
+			},
+			want: 1023,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := expectedGasLimit(tt.args.parentGasLimit, tt.args.targetGasLimit); got != tt.want {
+				t.Errorf("expectedGasLimit() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

beacon-chain/rpc/prysm/v1alpha1/validator/proposer_execution_payload.go

@@ -239,7 +239,8 @@ func (vs *Server) getTerminalBlockHashIfExists(ctx context.Context, transitionTi
 
 func (vs *Server) getBuilderPayloadAndBlobs(ctx context.Context,
 	slot primitives.Slot,
-	vIdx primitives.ValidatorIndex) (builder.Bid, error) {
+	vIdx primitives.ValidatorIndex,
+	parentGasLimit uint64) (builder.Bid, error) {
 	ctx, span := trace.StartSpan(ctx, "ProposerServer.getBuilderPayloadAndBlobs")
 	defer span.End()
 
@@ -255,7 +256,7 @@ func (vs *Server) getBuilderPayloadAndBlobs(ctx context.Context,
 		return nil, nil
 	}
 
-	return vs.getPayloadHeaderFromBuilder(ctx, slot, vIdx)
+	return vs.getPayloadHeaderFromBuilder(ctx, slot, vIdx, parentGasLimit)
 }
 
 var errActivationNotReached = errors.New("activation epoch not reached")

beacon-chain/rpc/service.go

@@ -14,8 +14,6 @@ import (
 	grpcopentracing "github.com/grpc-ecosystem/go-grpc-middleware/tracing/opentracing"
 	grpcprometheus "github.com/grpc-ecosystem/go-grpc-prometheus"
 	"github.com/pkg/errors"
-	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/client_golang/prometheus/promauto"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/blockchain"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/builder"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/cache"
@@ -57,24 +55,6 @@ import (
 
 const attestationBufferSize = 100
 
-var (
-	httpRequestLatency = promauto.NewHistogramVec(
-		prometheus.HistogramOpts{
-			Name:    "http_request_latency_seconds",
-			Help:    "Latency of HTTP requests in seconds",
-			Buckets: []float64{0.001, 0.01, 0.025, 0.1, 0.25, 1, 2.5, 10},
-		},
-		[]string{"endpoint", "code", "method"},
-	)
-	httpRequestCount = promauto.NewCounterVec(
-		prometheus.CounterOpts{
-			Name: "http_request_count",
-			Help: "Number of HTTP requests",
-		},
-		[]string{"endpoint", "code", "method"},
-	)
-)
-
 // Service defining an RPC server for a beacon node.
 type Service struct {
 	cfg                  *Config

beacon-chain/sync/BUILD.bazel

@@ -244,6 +244,7 @@ go_test(
         "//proto/prysm/v1alpha1:go_default_library",
         "//proto/prysm/v1alpha1/attestation:go_default_library",
         "//proto/prysm/v1alpha1/metadata:go_default_library",
+        "//runtime/version:go_default_library",
         "//testing/assert:go_default_library",
         "//testing/require:go_default_library",
         "//testing/util:go_default_library",

beacon-chain/sync/checkpoint/BUILD.bazel

@@ -10,6 +10,7 @@ go_library(
     importpath = "github.com/prysmaticlabs/prysm/v5/beacon-chain/sync/checkpoint",
     visibility = ["//visibility:public"],
     deps = [
+        "//api/client:go_default_library",
         "//api/client/beacon:go_default_library",
         "//beacon-chain/db:go_default_library",
         "//config/params:go_default_library",

beacon-chain/sync/checkpoint/api.go

@@ -4,6 +4,7 @@ import (
 	"context"
 
 	"github.com/pkg/errors"
+	"github.com/prysmaticlabs/prysm/v5/api/client"
 	"github.com/prysmaticlabs/prysm/v5/api/client/beacon"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/db"
 	"github.com/prysmaticlabs/prysm/v5/config/params"
@@ -18,7 +19,7 @@ type APIInitializer struct {
 // NewAPIInitializer creates an APIInitializer, handling the set up of a beacon node api client
 // using the provided host string.
 func NewAPIInitializer(beaconNodeHost string) (*APIInitializer, error) {
-	c, err := beacon.NewClient(beaconNodeHost)
+	c, err := beacon.NewClient(beaconNodeHost, client.WithMaxBodySize(client.MaxBodySizeState))
 	if err != nil {
 		return nil, errors.Wrapf(err, "unable to parse beacon node url or hostname - %s", beaconNodeHost)
 	}
@@ -32,10 +33,9 @@ func (dl *APIInitializer) Initialize(ctx context.Context, d db.Database) error {
 	if err == nil && origin != params.BeaconConfig().ZeroHash {
 		log.Warnf("Origin checkpoint root %#x found in db, ignoring checkpoint sync flags", origin)
 		return nil
-	} else {
-		if !errors.Is(err, db.ErrNotFound) {
-			return errors.Wrap(err, "error while checking database for origin root")
-		}
+	}
+	if err != nil && !errors.Is(err, db.ErrNotFound) {
+		return errors.Wrap(err, "error while checking database for origin root")
 	}
 	od, err := beacon.DownloadFinalizedData(ctx, dl.c)
 	if err != nil {

beacon-chain/sync/fork_watcher.go

@@ -1,6 +1,7 @@
 package sync
 
 import (
+	"github.com/libp2p/go-libp2p/core/protocol"
 	"github.com/pkg/errors"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/p2p"
 	"github.com/prysmaticlabs/prysm/v5/config/params"
@@ -39,87 +40,128 @@ func (s *Service) forkWatcher() {
 	}
 }
 
-// Checks if there is a fork in the next epoch and if there is
-// it registers the appropriate gossip and rpc topics.
-func (s *Service) registerForUpcomingFork(currEpoch primitives.Epoch) error {
-	genRoot := s.cfg.clock.GenesisValidatorsRoot()
-	isNextForkEpoch, err := forks.IsForkNextEpoch(s.cfg.clock.GenesisTime(), genRoot[:])
+// registerForUpcomingFork registers appropriate gossip and RPC topic if there is a fork in the next epoch.
+func (s *Service) registerForUpcomingFork(currentEpoch primitives.Epoch) error {
+	// Get the genesis validators root.
+	genesisValidatorsRoot := s.cfg.clock.GenesisValidatorsRoot()
+
+	// Check if there is a fork in the next epoch.
+	isForkNextEpoch, err := forks.IsForkNextEpoch(s.cfg.clock.GenesisTime(), genesisValidatorsRoot[:])
 	if err != nil {
 		return errors.Wrap(err, "Could not retrieve next fork epoch")
 	}
-	// In preparation for the upcoming fork
-	// in the following epoch, the node
-	// will subscribe the new topics in advance.
-	if isNextForkEpoch {
-		nextEpoch := currEpoch + 1
-		digest, err := forks.ForkDigestFromEpoch(nextEpoch, genRoot[:])
-		if err != nil {
-			return errors.Wrap(err, "could not retrieve fork digest")
-		}
-		if s.subHandler.digestExists(digest) {
-			return nil
-		}
-		s.registerSubscribers(nextEpoch, digest)
-		if nextEpoch == params.BeaconConfig().AltairForkEpoch {
-			s.registerRPCHandlersAltair()
-		}
-		if nextEpoch == params.BeaconConfig().DenebForkEpoch {
-			s.registerRPCHandlersDeneb()
-		}
-	}
-	return nil
-}
 
-// Checks if there was a fork in the previous epoch, and if there
-// was then we deregister the topics from that particular fork.
-func (s *Service) deregisterFromPastFork(currEpoch primitives.Epoch) error {
-	genRoot := s.cfg.clock.GenesisValidatorsRoot()
-	// This method takes care of the de-registration of
-	// old gossip pubsub handlers. Once we are at the epoch
-	// after the fork, we de-register from all the outdated topics.
-	currFork, err := forks.Fork(currEpoch)
-	if err != nil {
-		return err
-	}
-	// If we are still in our genesis fork version then
-	// we simply exit early.
-	if currFork.Epoch == params.BeaconConfig().GenesisEpoch {
+	// Exit early if there is no fork in the next epoch.
+	if !isForkNextEpoch {
 		return nil
 	}
-	epochAfterFork := currFork.Epoch + 1
-	// If we are in the epoch after the fork, we start de-registering.
-	if epochAfterFork == currEpoch {
-		// Look at the previous fork's digest.
-		epochBeforeFork := currFork.Epoch - 1
-		prevDigest, err := forks.ForkDigestFromEpoch(epochBeforeFork, genRoot[:])
-		if err != nil {
-			return errors.Wrap(err, "Failed to determine previous epoch fork digest")
-		}
 
-		// Exit early if there are no topics with that particular
-		// digest.
-		if !s.subHandler.digestExists(prevDigest) {
-			return nil
-		}
-		prevFork, err := forks.Fork(epochBeforeFork)
-		if err != nil {
-			return errors.Wrap(err, "failed to determine previous epoch fork data")
-		}
-		if prevFork.Epoch == params.BeaconConfig().GenesisEpoch {
-			s.unregisterPhase0Handlers()
-		}
-		// Run through all our current active topics and see
-		// if there are any subscriptions to be removed.
-		for _, t := range s.subHandler.allTopics() {
-			retDigest, err := p2p.ExtractGossipDigest(t)
-			if err != nil {
-				log.WithError(err).Error("Could not retrieve digest")
-				continue
-			}
-			if retDigest == prevDigest {
-				s.unSubscribeFromTopic(t)
-			}
-		}
+	beforeForkEpoch := currentEpoch
+	forkEpoch := beforeForkEpoch + 1
+
+	// Get the fork afterForkDigest for the next epoch.
+	afterForkDigest, err := forks.ForkDigestFromEpoch(forkEpoch, genesisValidatorsRoot[:])
+	if err != nil {
+		return errors.Wrap(err, "could not retrieve fork digest")
 	}
+
+	// Exit early if the topics for the next epoch are already registered.
+	// It likely to be the case for all slots of the epoch that are not the first one.
+	if s.subHandler.digestExists(afterForkDigest) {
+		return nil
+	}
+
+	// Register the subscribers (gossipsub) for the next epoch.
+	s.registerSubscribers(forkEpoch, afterForkDigest)
+
+	// Get the handlers for the current and next fork.
+	beforeForkHandlerByTopic, err := s.rpcHandlerByTopicFromEpoch(beforeForkEpoch)
+	if err != nil {
+		return errors.Wrap(err, "RPC handler by topic from before fork epoch")
+	}
+
+	forkHandlerByTopic, err := s.rpcHandlerByTopicFromEpoch(forkEpoch)
+	if err != nil {
+		return errors.Wrap(err, "RPC handler by topic from fork epoch")
+	}
+
+	// Compute newly added topics.
+	newRPCHandlerByTopic := addedRPCHandlerByTopic(beforeForkHandlerByTopic, forkHandlerByTopic)
+
+	// Register the new RPC handlers.
+	for topic, handler := range newRPCHandlerByTopic {
+		s.registerRPC(topic, handler)
+	}
+
+	return nil
+}
+
+// deregisterFromPastFork deregisters appropriate gossip and RPC topic if there is a fork in the current epoch.
+func (s *Service) deregisterFromPastFork(currentEpoch primitives.Epoch) error {
+	// Extract the genesis validators root.
+	genesisValidatorsRoot := s.cfg.clock.GenesisValidatorsRoot()
+
+	// Get the fork.
+	currentFork, err := forks.Fork(currentEpoch)
+	if err != nil {
+		return errors.Wrap(err, "genesis validators root")
+	}
+
+	// If we are still in our genesis fork version then exit early.
+	if currentFork.Epoch == params.BeaconConfig().GenesisEpoch {
+		return nil
+	}
+
+	// Get the epoch after the fork epoch.
+	afterForkEpoch := currentFork.Epoch + 1
+
+	// Start de-registering if the current epoch is after the fork epoch.
+	if currentEpoch != afterForkEpoch {
+		return nil
+	}
+
+	// Look at the previous fork's digest.
+	beforeForkEpoch := currentFork.Epoch - 1
+
+	beforeForkDigest, err := forks.ForkDigestFromEpoch(beforeForkEpoch, genesisValidatorsRoot[:])
+	if err != nil {
+		return errors.Wrap(err, "fork digest from epoch")
+	}
+
+	// Exit early if there are no topics with that particular digest.
+	if !s.subHandler.digestExists(beforeForkDigest) {
+		return nil
+	}
+
+	// Compute the RPC handlers that are no longer needed.
+	beforeForkHandlerByTopic, err := s.rpcHandlerByTopicFromEpoch(beforeForkEpoch)
+	if err != nil {
+		return errors.Wrap(err, "RPC handler by topic from before fork epoch")
+	}
+
+	forkHandlerByTopic, err := s.rpcHandlerByTopicFromEpoch(currentFork.Epoch)
+	if err != nil {
+		return errors.Wrap(err, "RPC handler by topic from fork epoch")
+	}
+
+	topicsToRemove := removedRPCTopics(beforeForkHandlerByTopic, forkHandlerByTopic)
+	for topic := range topicsToRemove {
+		fullTopic := topic + s.cfg.p2p.Encoding().ProtocolSuffix()
+		s.cfg.p2p.Host().RemoveStreamHandler(protocol.ID(fullTopic))
+	}
+
+	// Run through all our current active topics and see
+	// if there are any subscriptions to be removed.
+	for _, t := range s.subHandler.allTopics() {
+		retDigest, err := p2p.ExtractGossipDigest(t)
+		if err != nil {
+			log.WithError(err).Error("Could not retrieve digest")
+			continue
+		}
+		if retDigest == beforeForkDigest {
+			s.unSubscribeFromTopic(t)
+		}
+	}
+
 	return nil
 }