Add Strict Connection Manager (#4110)

* add forked connMgr * gaz * add license header * Merge branch 'master' of https://github.com/prysmaticlabs/geth-sharding into connMgr * add conn manager test * gaz * fix connManager * Merge branch 'master' of https://github.com/prysmaticlabs/geth-sharding into connMgr * gaz * remove todo * add new dep * lint * lint * lint * space * visibility * Merge branch 'master' into connMgr * Merge branch 'master' into connMgr * Merge refs/heads/master into connMgr
2026-01-08 23:18:15 -05:00 · 2019-12-04 02:18:57 +08:00
parent a2d4701f6e
commit 28c4f28d32
9 changed files with 1253 additions and 4 deletions
--- a/7
+++ b/7
@@ -1381,3 +1381,10 @@ go_repository(
    sum = "h1:HgqpYBng0n7tLJIlyT4kPCIv5XgCsF+kai1NnnrJzEU=",
    version = "v2.20.1+incompatible",
 )
+
+go_repository(
+    name = "com_github_ipfs_go_detect_race",
+    importpath = "github.com/ipfs/go-detect-race",
+    sum = "h1:qX/xay2W3E4Q1U7d9lNs1sU9nvguX0a7319XbyQ6cOk=",
+    version = "v0.0.1",
+)
--- a/beacon-chain/p2p/BUILD.bazel
+++ b/beacon-chain/p2p/BUILD.bazel
@@ -28,6 +28,7 @@ go_library(
        "//tools:__subpackages__",
    ],
    deps = [
+        "//beacon-chain/p2p/connmgr:go_default_library",
        "//beacon-chain/p2p/encoder:go_default_library",
        "//beacon-chain/p2p/peers:go_default_library",
        "//beacon-chain/sync/peerstatus:go_default_library",
@@ -48,7 +49,6 @@ go_library(
        "@com_github_libp2p_go_libp2p//:go_default_library",
        "@com_github_libp2p_go_libp2p//config:go_default_library",
        "@com_github_libp2p_go_libp2p//p2p/host/routed:go_default_library",
-        "@com_github_libp2p_go_libp2p_connmgr//:go_default_library",
        "@com_github_libp2p_go_libp2p_core//:go_default_library",
        "@com_github_libp2p_go_libp2p_core//crypto:go_default_library",
        "@com_github_libp2p_go_libp2p_core//host:go_default_library",
--- a/beacon-chain/p2p/connmgr/BUILD.bazel
+++ b/beacon-chain/p2p/connmgr/BUILD.bazel
@@ -0,0 +1,28 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["connmgr.go"],
+    importpath = "github.com/prysmaticlabs/prysm/beacon-chain/p2p/connmgr",
+    visibility = ["//beacon-chain:__subpackages__"],
+    deps = [
+        "@com_github_ipfs_go_log//:go_default_library",
+        "@com_github_libp2p_go_libp2p_core//connmgr:go_default_library",
+        "@com_github_libp2p_go_libp2p_core//network:go_default_library",
+        "@com_github_libp2p_go_libp2p_core//peer:go_default_library",
+        "@com_github_multiformats_go_multiaddr//:go_default_library",
+    ],
+)
+
+go_test(
+    name = "go_default_test",
+    srcs = ["connmgr_test.go"],
+    embed = [":go_default_library"],
+    deps = [
+        "@com_github_ipfs_go_detect_race//:go_default_library",
+        "@com_github_libp2p_go_libp2p_core//network:go_default_library",
+        "@com_github_libp2p_go_libp2p_core//peer:go_default_library",
+        "@com_github_libp2p_go_libp2p_core//test:go_default_library",
+        "@com_github_multiformats_go_multiaddr//:go_default_library",
+    ],
+)
--- a/beacon-chain/p2p/connmgr/connmgr.go
+++ b/beacon-chain/p2p/connmgr/connmgr.go
@@ -0,0 +1,521 @@
+/*
+Copyright 2019. Protocol Labs, Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+*/
+
+// Package connmgr : This file is forked from github.com/libp2p/go-libp2p-core/connmgr/connmgr.go
+package connmgr
+
+import (
+	"context"
+	"sort"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	logging "github.com/ipfs/go-log"
+	"github.com/libp2p/go-libp2p-core/connmgr"
+	"github.com/libp2p/go-libp2p-core/network"
+	"github.com/libp2p/go-libp2p-core/peer"
+	ma "github.com/multiformats/go-multiaddr"
+)
+
+// SilencePeriod refers to the period in which a connection is given leeway by the connection
+// manager before it is handled normally.
+var SilencePeriod = 5 * time.Second
+
+// TickerPeriod represents the frequency in which we check the number of
+// open connections.
+var TickerPeriod = 5 * time.Second
+
+var log = logging.Logger("connmgr")
+
+// BasicConnMgr is a ConnManager that trims connections whenever the count exceeds the
+// high watermark. New connections are given a grace period before they're subject
+// to trimming. Trims are automatically run on demand, only if the time from the
+// previous trim is higher than 10 seconds. Furthermore, trims can be explicitly
+// requested through the public interface of this struct (see TrimOpenConns).
+//
+// See configuration parameters in NewConnManager.
+type BasicConnMgr struct {
+	highWater   int
+	lowWater    int
+	connCount   int32
+	gracePeriod time.Duration
+	segments    segments
+
+	plk       sync.RWMutex
+	protected map[peer.ID]map[string]struct{}
+
+	// channel-based semaphore that enforces only a single trim is in progress
+	trimRunningCh chan struct{}
+	lastTrim      time.Time
+	silencePeriod time.Duration
+
+	ctx    context.Context
+	cancel func()
+}
+
+var _ connmgr.ConnManager = (*BasicConnMgr)(nil)
+
+type segment struct {
+	sync.Mutex
+	peers map[peer.ID]*peerInfo
+}
+
+type segments [256]*segment
+
+func (ss *segments) get(p peer.ID) *segment {
+	return ss[byte(p[len(p)-1])]
+}
+
+func (ss *segments) countPeers() (count int) {
+	for _, seg := range ss {
+		seg.Lock()
+		count += len(seg.peers)
+		seg.Unlock()
+	}
+	return count
+}
+
+func (s *segment) tagInfoFor(p peer.ID) *peerInfo {
+	pi, ok := s.peers[p]
+	if ok {
+		return pi
+	}
+	// create a temporary peer to buffer early tags before the Connected notification arrives.
+	pi = &peerInfo{
+		id:        p,
+		firstSeen: time.Now(), // this timestamp will be updated when the first Connected notification arrives.
+		temp:      true,
+		tags:      make(map[string]int),
+		conns:     make(map[network.Conn]time.Time),
+	}
+	s.peers[p] = pi
+	return pi
+}
+
+// NewConnManager creates a new BasicConnMgr with the provided params:
+// * lo and hi are watermarks governing the number of connections that'll be maintained.
+//   When the peer count exceeds the 'high watermark', as many peers will be pruned (and
+//   their connections terminated) until 'low watermark' peers remain.
+// * grace is the amount of time a newly opened connection is given before it becomes
+//   subject to pruning.
+func NewConnManager(low, hi int, grace time.Duration) *BasicConnMgr {
+	ctx, cancel := context.WithCancel(context.Background())
+	cm := &BasicConnMgr{
+		highWater:     hi,
+		lowWater:      low,
+		gracePeriod:   grace,
+		trimRunningCh: make(chan struct{}, 1),
+		protected:     make(map[peer.ID]map[string]struct{}, 16),
+		silencePeriod: SilencePeriod,
+		ctx:           ctx,
+		cancel:        cancel,
+		segments: func() (ret segments) {
+			for i := range ret {
+				ret[i] = &segment{
+					peers: make(map[peer.ID]*peerInfo),
+				}
+			}
+			return ret
+		}(),
+	}
+
+	go cm.background()
+	return cm
+}
+
+// Close shutsdown the connection manager.
+func (cm *BasicConnMgr) Close() error {
+	cm.cancel()
+	return nil
+}
+
+// Protect is used to protect a peer from being pruned by the
+// connection manager.
+func (cm *BasicConnMgr) Protect(id peer.ID, tag string) {
+	cm.plk.Lock()
+	defer cm.plk.Unlock()
+
+	tags, ok := cm.protected[id]
+	if !ok {
+		tags = make(map[string]struct{}, 2)
+		cm.protected[id] = tags
+	}
+	tags[tag] = struct{}{}
+}
+
+// Unprotect is used to remove the protection a previously protected peer
+// so that it can be normally pruned by the connection manager.
+func (cm *BasicConnMgr) Unprotect(id peer.ID, tag string) (protected bool) {
+	cm.plk.Lock()
+	defer cm.plk.Unlock()
+
+	tags, ok := cm.protected[id]
+	if !ok {
+		return false
+	}
+	if delete(tags, tag); len(tags) == 0 {
+		delete(cm.protected, id)
+		return false
+	}
+	return true
+}
+
+// peerInfo stores metadata for a given peer.
+type peerInfo struct {
+	id    peer.ID
+	tags  map[string]int // value for each tag
+	value int            // cached sum of all tag values
+	temp  bool           // this is a temporary entry holding early tags, and awaiting connections
+
+	conns map[network.Conn]time.Time // start time of each connection
+
+	firstSeen time.Time // timestamp when we began tracking this peer.
+}
+
+// TrimOpenConns closes the connections of as many peers as needed to make the peer count
+// equal the low watermark. Peers are sorted in ascending order based on their total value,
+// pruning those peers with the lowest scores first, as long as they are not within their
+// grace period.
+//
+// (a) there's another trim in progress, or (b) the silence period is in effect.
+func (cm *BasicConnMgr) TrimOpenConns(ctx context.Context) {
+	select {
+	case cm.trimRunningCh <- struct{}{}:
+	default:
+		return
+	}
+	defer func() { <-cm.trimRunningCh }()
+	if time.Since(cm.lastTrim) < cm.silencePeriod {
+		// skip this attempt to trim as the last one just took place.
+		return
+	}
+
+	defer log.EventBegin(ctx, "connCleanup").Done()
+	for _, c := range cm.getConnsToClose(ctx) {
+		log.Info("closing conn: ", c.RemotePeer())
+		log.Event(ctx, "closeConn", c.RemotePeer())
+		c.Close()
+	}
+
+	cm.lastTrim = time.Now()
+}
+
+func (cm *BasicConnMgr) background() {
+	ticker := time.NewTicker(TickerPeriod)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-ticker.C:
+			if atomic.LoadInt32(&cm.connCount) > int32(cm.highWater) {
+				cm.TrimOpenConns(cm.ctx)
+			}
+
+		case <-cm.ctx.Done():
+			return
+		}
+	}
+}
+
+// getConnsToClose runs the heuristics described in TrimOpenConns and returns the
+// connections to close.
+func (cm *BasicConnMgr) getConnsToClose(ctx context.Context) []network.Conn {
+	if cm.lowWater == 0 || cm.highWater == 0 {
+		// disabled
+		return nil
+	}
+
+	nconns := int(atomic.LoadInt32(&cm.connCount))
+	if nconns <= cm.lowWater {
+		log.Info("open connection count below limit")
+		return nil
+	}
+
+	npeers := cm.segments.countPeers()
+	candidates := make([]*peerInfo, 0, npeers)
+	ncandidates := 0
+	gracePeriodStart := time.Now().Add(-cm.gracePeriod)
+
+	cm.plk.RLock()
+	for _, s := range cm.segments {
+		s.Lock()
+		for id, inf := range s.peers {
+			if _, ok := cm.protected[id]; ok {
+				// skip over protected peer.
+				continue
+			}
+			if inf.firstSeen.After(gracePeriodStart) {
+				// skip peers in the grace period.
+				continue
+			}
+			candidates = append(candidates, inf)
+			ncandidates += len(inf.conns)
+		}
+		s.Unlock()
+	}
+	cm.plk.RUnlock()
+
+	if ncandidates < cm.lowWater {
+		log.Info("open connection count above limit but too many are in the grace period")
+		// We have too many connections but fewer than lowWater
+		// connections out of the grace period.
+		//
+		// If we trimmed now, we'd kill potentially useful connections.
+		return nil
+	}
+
+	// Sort peers according to their value.
+	sort.Slice(candidates, func(i, j int) bool {
+		left, right := candidates[i], candidates[j]
+		// temporary peers are preferred for pruning.
+		if left.temp != right.temp {
+			return left.temp
+		}
+		// otherwise, compare by value.
+		return left.value < right.value
+	})
+
+	target := ncandidates - cm.lowWater
+
+	// slightly overallocate because we may have more than one conns per peer
+	selected := make([]network.Conn, 0, target+10)
+
+	for _, inf := range candidates {
+		if target <= 0 {
+			break
+		}
+
+		// lock this to protect from concurrent modifications from connect/disconnect events
+		s := cm.segments.get(inf.id)
+		s.Lock()
+
+		if len(inf.conns) == 0 && inf.temp {
+			// handle temporary entries for early tags -- this entry has gone past the grace period
+			// and still holds no connections, so prune it.
+			delete(s.peers, inf.id)
+		} else {
+			for c := range inf.conns {
+				selected = append(selected, c)
+			}
+		}
+		target -= len(inf.conns)
+		s.Unlock()
+	}
+
+	return selected
+}
+
+// GetTagInfo is called to fetch the tag information associated with a given
+// peer, nil is returned if p refers to an unknown peer.
+func (cm *BasicConnMgr) GetTagInfo(p peer.ID) *connmgr.TagInfo {
+	s := cm.segments.get(p)
+	s.Lock()
+	defer s.Unlock()
+
+	pi, ok := s.peers[p]
+	if !ok {
+		return nil
+	}
+
+	out := &connmgr.TagInfo{
+		FirstSeen: pi.firstSeen,
+		Value:     pi.value,
+		Tags:      make(map[string]int),
+		Conns:     make(map[string]time.Time),
+	}
+
+	for t, v := range pi.tags {
+		out.Tags[t] = v
+	}
+	for c, t := range pi.conns {
+		out.Conns[c.RemoteMultiaddr().String()] = t
+	}
+
+	return out
+}
+
+// TagPeer is called to associate a string and integer with a given peer.
+func (cm *BasicConnMgr) TagPeer(p peer.ID, tag string, val int) {
+	s := cm.segments.get(p)
+	s.Lock()
+	defer s.Unlock()
+
+	pi := s.tagInfoFor(p)
+
+	// Update the total value of the peer.
+	pi.value += val - pi.tags[tag]
+	pi.tags[tag] = val
+}
+
+// UntagPeer is called to disassociate a string and integer from a given peer.
+func (cm *BasicConnMgr) UntagPeer(p peer.ID, tag string) {
+	s := cm.segments.get(p)
+	s.Lock()
+	defer s.Unlock()
+
+	pi, ok := s.peers[p]
+	if !ok {
+		log.Info("tried to remove tag from untracked peer: ", p)
+		return
+	}
+
+	// Update the total value of the peer.
+	pi.value -= pi.tags[tag]
+	delete(pi.tags, tag)
+}
+
+// UpsertTag is called to insert/update a peer tag
+func (cm *BasicConnMgr) UpsertTag(p peer.ID, tag string, upsert func(int) int) {
+	s := cm.segments.get(p)
+	s.Lock()
+	defer s.Unlock()
+
+	pi := s.tagInfoFor(p)
+
+	oldval := pi.tags[tag]
+	newval := upsert(oldval)
+	pi.value += newval - oldval
+	pi.tags[tag] = newval
+}
+
+// CMInfo holds the configuration for BasicConnMgr, as well as status data.
+type CMInfo struct {
+	// The low watermark, as described in NewConnManager.
+	LowWater int
+
+	// The high watermark, as described in NewConnManager.
+	HighWater int
+
+	// The timestamp when the last trim was triggered.
+	LastTrim time.Time
+
+	// The configured grace period, as described in NewConnManager.
+	GracePeriod time.Duration
+
+	// The current connection count.
+	ConnCount int
+}
+
+// GetInfo returns the configuration and status data for this connection manager.
+func (cm *BasicConnMgr) GetInfo() CMInfo {
+	return CMInfo{
+		HighWater:   cm.highWater,
+		LowWater:    cm.lowWater,
+		LastTrim:    cm.lastTrim,
+		GracePeriod: cm.gracePeriod,
+		ConnCount:   int(atomic.LoadInt32(&cm.connCount)),
+	}
+}
+
+// Notifee returns a sink through which Notifiers can inform the BasicConnMgr when
+// events occur. Currently, the notifee only reacts upon connection events
+// {Connected, Disconnected}.
+func (cm *BasicConnMgr) Notifee() network.Notifiee {
+	return (*cmNotifee)(cm)
+}
+
+type cmNotifee BasicConnMgr
+
+func (nn *cmNotifee) cm() *BasicConnMgr {
+	return (*BasicConnMgr)(nn)
+}
+
+// Connected is called by notifiers to inform that a new connection has been established.
+// The notifee updates the BasicConnMgr to start tracking the connection. If the new connection
+// count exceeds the high watermark, a trim may be triggered.
+func (nn *cmNotifee) Connected(n network.Network, c network.Conn) {
+	cm := nn.cm()
+
+	p := c.RemotePeer()
+	s := cm.segments.get(p)
+	s.Lock()
+	defer s.Unlock()
+
+	id := c.RemotePeer()
+	pinfo, ok := s.peers[id]
+	if !ok {
+		pinfo = &peerInfo{
+			id:        id,
+			firstSeen: time.Now(),
+			tags:      make(map[string]int),
+			conns:     make(map[network.Conn]time.Time),
+		}
+		s.peers[id] = pinfo
+	} else if pinfo.temp {
+		// we had created a temporary entry for this peer to buffer early tags before the
+		// Connected notification arrived: flip the temporary flag, and update the firstSeen
+		// timestamp to the real one.
+		pinfo.temp = false
+		pinfo.firstSeen = time.Now()
+	}
+
+	_, ok = pinfo.conns[c]
+	if ok {
+		log.Error("received connected notification for conn we are already tracking: ", p)
+		return
+	}
+
+	pinfo.conns[c] = time.Now()
+	atomic.AddInt32(&cm.connCount, 1)
+}
+
+// Disconnected is called by notifiers to inform that an existing connection has been closed or terminated.
+// The notifee updates the BasicConnMgr accordingly to stop tracking the connection, and performs housekeeping.
+func (nn *cmNotifee) Disconnected(n network.Network, c network.Conn) {
+	cm := nn.cm()
+
+	p := c.RemotePeer()
+	s := cm.segments.get(p)
+	s.Lock()
+	defer s.Unlock()
+
+	cinf, ok := s.peers[p]
+	if !ok {
+		log.Error("received disconnected notification for peer we are not tracking: ", p)
+		return
+	}
+
+	_, ok = cinf.conns[c]
+	if !ok {
+		log.Error("received disconnected notification for conn we are not tracking: ", p)
+		return
+	}
+
+	delete(cinf.conns, c)
+	if len(cinf.conns) == 0 {
+		delete(s.peers, p)
+	}
+	atomic.AddInt32(&cm.connCount, -1)
+}
+
+// Listen is no-op in this implementation.
+func (nn *cmNotifee) Listen(n network.Network, addr ma.Multiaddr) {}
+
+// ListenClose is no-op in this implementation.
+func (nn *cmNotifee) ListenClose(n network.Network, addr ma.Multiaddr) {}
+
+// OpenedStream is no-op in this implementation.
+func (nn *cmNotifee) OpenedStream(network.Network, network.Stream) {}
+
+// ClosedStream is no-op in this implementation.
+func (nn *cmNotifee) ClosedStream(network.Network, network.Stream) {}
--- a/beacon-chain/p2p/connmgr/connmgr_test.go
+++ b/beacon-chain/p2p/connmgr/connmgr_test.go
@@ -0,0 +1,681 @@
+package connmgr
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	detectrace "github.com/ipfs/go-detect-race"
+
+	"github.com/libp2p/go-libp2p-core/network"
+	"github.com/libp2p/go-libp2p-core/peer"
+
+	tu "github.com/libp2p/go-libp2p-core/test"
+	ma "github.com/multiformats/go-multiaddr"
+)
+
+type tconn struct {
+	network.Conn
+
+	peer             peer.ID
+	closed           bool
+	disconnectNotify func(net network.Network, conn network.Conn)
+}
+
+func (c *tconn) Close() error {
+	c.closed = true
+	if c.disconnectNotify != nil {
+		c.disconnectNotify(nil, c)
+	}
+	return nil
+}
+
+func (c *tconn) RemotePeer() peer.ID {
+	return c.peer
+}
+
+func (c *tconn) RemoteMultiaddr() ma.Multiaddr {
+	addr, err := ma.NewMultiaddr("/ip4/127.0.0.1/udp/1234")
+	if err != nil {
+		panic("cannot create multiaddr")
+	}
+	return addr
+}
+
+func randConn(t testing.TB, discNotify func(network.Network, network.Conn)) network.Conn {
+	pid := tu.RandPeerIDFatal(t)
+	return &tconn{peer: pid, disconnectNotify: discNotify}
+}
+
+func TestConnTrimming(t *testing.T) {
+	cm := NewConnManager(200, 300, 0)
+	not := cm.Notifee()
+
+	var conns []network.Conn
+	for i := 0; i < 300; i++ {
+		rc := randConn(t, nil)
+		conns = append(conns, rc)
+		not.Connected(nil, rc)
+	}
+
+	for _, c := range conns {
+		if c.(*tconn).closed {
+			t.Fatal("nothing should be closed yet")
+		}
+	}
+
+	for i := 0; i < 100; i++ {
+		cm.TagPeer(conns[i].RemotePeer(), "foo", 10)
+	}
+
+	cm.TagPeer(conns[299].RemotePeer(), "badfoo", -5)
+
+	cm.TrimOpenConns(context.Background())
+
+	for i := 0; i < 100; i++ {
+		c := conns[i]
+		if c.(*tconn).closed {
+			t.Fatal("these shouldnt be closed")
+		}
+	}
+
+	if !conns[299].(*tconn).closed {
+		t.Fatal("conn with bad tag should have gotten closed")
+	}
+}
+
+func TestConnsToClose(t *testing.T) {
+	cm := NewConnManager(0, 10, 0)
+	conns := cm.getConnsToClose(context.Background())
+	if conns != nil {
+		t.Fatal("expected no connections")
+	}
+
+	cm = NewConnManager(10, 0, 0)
+	conns = cm.getConnsToClose(context.Background())
+	if conns != nil {
+		t.Fatal("expected no connections")
+	}
+
+	cm = NewConnManager(1, 1, 0)
+	conns = cm.getConnsToClose(context.Background())
+	if conns != nil {
+		t.Fatal("expected no connections")
+	}
+
+	cm = NewConnManager(1, 1, time.Duration(10*time.Minute))
+	not := cm.Notifee()
+	for i := 0; i < 5; i++ {
+		conn := randConn(t, nil)
+		not.Connected(nil, conn)
+	}
+	conns = cm.getConnsToClose(context.Background())
+	if len(conns) != 0 {
+		t.Fatal("expected no connections")
+	}
+}
+
+func TestGetTagInfo(t *testing.T) {
+	start := time.Now()
+	cm := NewConnManager(1, 1, time.Duration(10*time.Minute))
+	not := cm.Notifee()
+	conn := randConn(t, nil)
+	not.Connected(nil, conn)
+	end := time.Now()
+
+	other := tu.RandPeerIDFatal(t)
+	tag := cm.GetTagInfo(other)
+	if tag != nil {
+		t.Fatal("expected no tag")
+	}
+
+	tag = cm.GetTagInfo(conn.RemotePeer())
+	if tag == nil {
+		t.Fatal("expected tag")
+	}
+	if tag.FirstSeen.Before(start) || tag.FirstSeen.After(end) {
+		t.Fatal("expected first seen time")
+	}
+	if tag.Value != 0 {
+		t.Fatal("expected zero value")
+	}
+	if len(tag.Tags) != 0 {
+		t.Fatal("expected no tags")
+	}
+	if len(tag.Conns) != 1 {
+		t.Fatal("expected one connection")
+	}
+	for s, tm := range tag.Conns {
+		if s != conn.RemoteMultiaddr().String() {
+			t.Fatal("unexpected multiaddr")
+		}
+		if tm.Before(start) || tm.After(end) {
+			t.Fatal("unexpected connection time")
+		}
+	}
+
+	cm.TagPeer(conn.RemotePeer(), "tag", 5)
+	tag = cm.GetTagInfo(conn.RemotePeer())
+	if tag == nil {
+		t.Fatal("expected tag")
+	}
+	if tag.FirstSeen.Before(start) || tag.FirstSeen.After(end) {
+		t.Fatal("expected first seen time")
+	}
+	if tag.Value != 5 {
+		t.Fatal("expected five value")
+	}
+	if len(tag.Tags) != 1 {
+		t.Fatal("expected no tags")
+	}
+	for tString, v := range tag.Tags {
+		if tString != "tag" || v != 5 {
+			t.Fatal("expected tag value")
+		}
+	}
+	if len(tag.Conns) != 1 {
+		t.Fatal("expected one connection")
+	}
+	for s, tm := range tag.Conns {
+		if s != conn.RemoteMultiaddr().String() {
+			t.Fatal("unexpected multiaddr")
+		}
+		if tm.Before(start) || tm.After(end) {
+			t.Fatal("unexpected connection time")
+		}
+	}
+}
+
+func TestTagPeerNonExistant(t *testing.T) {
+	cm := NewConnManager(1, 1, time.Duration(10*time.Minute))
+
+	id := tu.RandPeerIDFatal(t)
+	cm.TagPeer(id, "test", 1)
+
+	if !cm.segments.get(id).peers[id].temp {
+		t.Fatal("expected 1 temporary entry")
+	}
+}
+
+func TestUntagPeer(t *testing.T) {
+	cm := NewConnManager(1, 1, time.Duration(10*time.Minute))
+	not := cm.Notifee()
+	conn := randConn(t, nil)
+	not.Connected(nil, conn)
+	rp := conn.RemotePeer()
+	cm.TagPeer(rp, "tag", 5)
+	cm.TagPeer(rp, "tag two", 5)
+
+	id := tu.RandPeerIDFatal(t)
+	cm.UntagPeer(id, "test")
+	if len(cm.segments.get(rp).peers[rp].tags) != 2 {
+		t.Fatal("expected tags to be uneffected")
+	}
+
+	cm.UntagPeer(conn.RemotePeer(), "test")
+	if len(cm.segments.get(rp).peers[rp].tags) != 2 {
+		t.Fatal("expected tags to be uneffected")
+	}
+
+	cm.UntagPeer(conn.RemotePeer(), "tag")
+	if len(cm.segments.get(rp).peers[rp].tags) != 1 {
+		t.Fatal("expected tag to be removed")
+	}
+	if cm.segments.get(rp).peers[rp].value != 5 {
+		t.Fatal("expected aggreagte tag value to be 5")
+	}
+}
+
+func TestGetInfo(t *testing.T) {
+	start := time.Now()
+	gp := time.Duration(10 * time.Minute)
+	cm := NewConnManager(1, 5, gp)
+	not := cm.Notifee()
+	conn := randConn(t, nil)
+	not.Connected(nil, conn)
+	cm.TrimOpenConns(context.Background())
+	end := time.Now()
+
+	info := cm.GetInfo()
+	if info.HighWater != 5 {
+		t.Fatal("expected highwater to be 5")
+	}
+	if info.LowWater != 1 {
+		t.Fatal("expected highwater to be 1")
+	}
+	if info.LastTrim.Before(start) || info.LastTrim.After(end) {
+		t.Fatal("unexpected last trim time")
+	}
+	if info.GracePeriod != gp {
+		t.Fatal("unexpected grace period")
+	}
+	if info.ConnCount != 1 {
+		t.Fatal("unexpected number of connections")
+	}
+}
+
+func TestDoubleConnection(t *testing.T) {
+	gp := time.Duration(10 * time.Minute)
+	cm := NewConnManager(1, 5, gp)
+	not := cm.Notifee()
+	conn := randConn(t, nil)
+	not.Connected(nil, conn)
+	cm.TagPeer(conn.RemotePeer(), "foo", 10)
+	not.Connected(nil, conn)
+	if cm.connCount != 1 {
+		t.Fatal("unexpected number of connections")
+	}
+	if cm.segments.get(conn.RemotePeer()).peers[conn.RemotePeer()].value != 10 {
+		t.Fatal("unexpected peer value")
+	}
+}
+
+func TestDisconnected(t *testing.T) {
+	gp := time.Duration(10 * time.Minute)
+	cm := NewConnManager(1, 5, gp)
+	not := cm.Notifee()
+	conn := randConn(t, nil)
+	not.Connected(nil, conn)
+	cm.TagPeer(conn.RemotePeer(), "foo", 10)
+
+	not.Disconnected(nil, randConn(t, nil))
+	if cm.connCount != 1 {
+		t.Fatal("unexpected number of connections")
+	}
+	if cm.segments.get(conn.RemotePeer()).peers[conn.RemotePeer()].value != 10 {
+		t.Fatal("unexpected peer value")
+	}
+
+	not.Disconnected(nil, &tconn{peer: conn.RemotePeer()})
+	if cm.connCount != 1 {
+		t.Fatal("unexpected number of connections")
+	}
+	if cm.segments.get(conn.RemotePeer()).peers[conn.RemotePeer()].value != 10 {
+		t.Fatal("unexpected peer value")
+	}
+
+	not.Disconnected(nil, conn)
+	if cm.connCount != 0 {
+		t.Fatal("unexpected number of connections")
+	}
+	if cm.segments.countPeers() != 0 {
+		t.Fatal("unexpected number of peers")
+	}
+}
+
+func TestGracePeriod(t *testing.T) {
+	if detectrace.WithRace() {
+		t.Skip("race detector is unhappy with this test")
+	}
+
+	SilencePeriod = 0
+	cm := NewConnManager(10, 20, 100*time.Millisecond)
+	SilencePeriod = 10 * time.Second
+
+	not := cm.Notifee()
+
+	var conns []network.Conn
+
+	// Add a connection and wait the grace period.
+	{
+		rc := randConn(t, not.Disconnected)
+		conns = append(conns, rc)
+		not.Connected(nil, rc)
+
+		time.Sleep(200 * time.Millisecond)
+
+		if rc.(*tconn).closed {
+			t.Fatal("expected conn to remain open")
+		}
+	}
+
+	// quickly add 30 connections (sending us above the high watermark)
+	for i := 0; i < 30; i++ {
+		rc := randConn(t, not.Disconnected)
+		conns = append(conns, rc)
+		not.Connected(nil, rc)
+	}
+
+	cm.TrimOpenConns(context.Background())
+
+	for _, c := range conns {
+		if c.(*tconn).closed {
+			t.Fatal("expected no conns to be closed")
+		}
+	}
+
+	time.Sleep(200 * time.Millisecond)
+
+	cm.TrimOpenConns(context.Background())
+
+	closed := 0
+	for _, c := range conns {
+		if c.(*tconn).closed {
+			closed++
+		}
+	}
+
+	if closed != 21 {
+		t.Fatal("expected to have closed 21 connections")
+	}
+}
+
+// see https://github.com/libp2p/go-libp2p-connmgr/issues/23
+func TestQuickBurstRespectsSilencePeriod(t *testing.T) {
+	if detectrace.WithRace() {
+		t.Skip("race detector is unhappy with this test")
+	}
+
+	cm := NewConnManager(10, 20, 0)
+	not := cm.Notifee()
+
+	var conns []network.Conn
+
+	// quickly produce 30 connections (sending us above the high watermark)
+	for i := 0; i < 30; i++ {
+		rc := randConn(t, not.Disconnected)
+		conns = append(conns, rc)
+		not.Connected(nil, rc)
+	}
+
+	// wait for a few seconds
+	time.Sleep(time.Second * 3)
+
+	// only the first trim is allowed in; make sure we close at most 20 connections, not all of them.
+	var closed int
+	for _, c := range conns {
+		if c.(*tconn).closed {
+			closed++
+		}
+	}
+	if closed > 20 {
+		t.Fatalf("should have closed at most 20 connections, closed: %d", closed)
+	}
+	if total := closed + int(cm.connCount); total != 30 {
+		t.Fatalf("expected closed connections + open conn count to equal 30, value: %d", total)
+	}
+}
+
+func TestPeerProtectionSingleTag(t *testing.T) {
+	if detectrace.WithRace() {
+		t.Skip("race detector is unhappy with this test")
+	}
+
+	SilencePeriod = 0
+	cm := NewConnManager(19, 20, 0)
+	SilencePeriod = 10 * time.Second
+
+	not := cm.Notifee()
+
+	var conns []network.Conn
+	addConn := func(value int) {
+		rc := randConn(t, not.Disconnected)
+		conns = append(conns, rc)
+		not.Connected(nil, rc)
+		cm.TagPeer(rc.RemotePeer(), "test", value)
+	}
+
+	// produce 20 connections with unique peers.
+	for i := 0; i < 20; i++ {
+		addConn(20)
+	}
+
+	// protect the first 5 peers.
+	var protected []network.Conn
+	for _, c := range conns[0:5] {
+		cm.Protect(c.RemotePeer(), "global")
+		protected = append(protected, c)
+		// tag them negatively to make them preferred for pruning.
+		cm.TagPeer(c.RemotePeer(), "test", -100)
+	}
+
+	// add 1 more conn, this shouldn't send us over the limit as protected conns don't count
+	addConn(20)
+
+	cm.TrimOpenConns(context.Background())
+
+	for _, c := range conns {
+		if c.(*tconn).closed {
+			t.Error("connection was closed by connection manager")
+		}
+	}
+
+	// add 5 more connection, sending the connection manager overboard.
+	for i := 0; i < 5; i++ {
+		addConn(20)
+	}
+
+	cm.TrimOpenConns(context.Background())
+
+	for _, c := range protected {
+		if c.(*tconn).closed {
+			t.Error("protected connection was closed by connection manager")
+		}
+	}
+
+	closed := 0
+	for _, c := range conns {
+		if c.(*tconn).closed {
+			closed++
+		}
+	}
+	if closed != 2 {
+		t.Errorf("expected 2 connection to be closed, found %d", closed)
+	}
+
+	// unprotect the first peer.
+	cm.Unprotect(protected[0].RemotePeer(), "global")
+
+	// add 2 more connections, sending the connection manager overboard again.
+	for i := 0; i < 2; i++ {
+		addConn(20)
+	}
+
+	cm.TrimOpenConns(context.Background())
+
+	if !protected[0].(*tconn).closed {
+		t.Error("unprotected connection was kept open by connection manager")
+	}
+	for _, c := range protected[1:] {
+		if c.(*tconn).closed {
+			t.Error("protected connection was closed by connection manager")
+		}
+	}
+}
+
+func TestPeerProtectionMultipleTags(t *testing.T) {
+	if detectrace.WithRace() {
+		t.Skip("race detector is unhappy with this test")
+	}
+
+	SilencePeriod = 0
+	cm := NewConnManager(19, 20, 0)
+	SilencePeriod = 10 * time.Second
+
+	not := cm.Notifee()
+
+	// produce 20 connections with unique peers.
+	var conns []network.Conn
+	for i := 0; i < 20; i++ {
+		rc := randConn(t, not.Disconnected)
+		conns = append(conns, rc)
+		not.Connected(nil, rc)
+		cm.TagPeer(rc.RemotePeer(), "test", 20)
+	}
+
+	// protect the first 5 peers under two tags.
+	var protected []network.Conn
+	for _, c := range conns[0:5] {
+		cm.Protect(c.RemotePeer(), "tag1")
+		cm.Protect(c.RemotePeer(), "tag2")
+		protected = append(protected, c)
+		// tag them negatively to make them preferred for pruning.
+		cm.TagPeer(c.RemotePeer(), "test", -100)
+	}
+
+	// add one more connection, sending the connection manager overboard.
+	not.Connected(nil, randConn(t, not.Disconnected))
+
+	cm.TrimOpenConns(context.Background())
+
+	for _, c := range protected {
+		if c.(*tconn).closed {
+			t.Error("protected connection was closed by connection manager")
+		}
+	}
+
+	// remove the protection from one tag.
+	for _, c := range protected {
+		if !cm.Unprotect(c.RemotePeer(), "tag1") {
+			t.Error("peer should still be protected")
+		}
+	}
+
+	// add 2 more connections, sending the connection manager overboard again.
+	for i := 0; i < 2; i++ {
+		rc := randConn(t, not.Disconnected)
+		conns = append(conns, rc)
+		not.Connected(nil, rc)
+		cm.TagPeer(rc.RemotePeer(), "test", 20)
+	}
+
+	cm.TrimOpenConns(context.Background())
+
+	// connections should still remain open, as they were protected.
+	for _, c := range protected[0:] {
+		if c.(*tconn).closed {
+			t.Error("protected connection was closed by connection manager")
+		}
+	}
+
+	// unprotect the first peer entirely.
+	cm.Unprotect(protected[0].RemotePeer(), "tag2")
+
+	// add 2 more connections, sending the connection manager overboard again.
+	for i := 0; i < 2; i++ {
+		rc := randConn(t, not.Disconnected)
+		conns = append(conns, rc)
+		not.Connected(nil, rc)
+		cm.TagPeer(rc.RemotePeer(), "test", 20)
+	}
+
+	cm.TrimOpenConns(context.Background())
+
+	if !protected[0].(*tconn).closed {
+		t.Error("unprotected connection was kept open by connection manager")
+	}
+	for _, c := range protected[1:] {
+		if c.(*tconn).closed {
+			t.Error("protected connection was closed by connection manager")
+		}
+	}
+
+}
+
+func TestPeerProtectionIdempotent(t *testing.T) {
+	SilencePeriod = 0
+	cm := NewConnManager(10, 20, 0)
+	SilencePeriod = 10 * time.Second
+
+	id, _ := tu.RandPeerID()
+	cm.Protect(id, "global")
+	cm.Protect(id, "global")
+	cm.Protect(id, "global")
+	cm.Protect(id, "global")
+
+	if len(cm.protected[id]) > 1 {
+		t.Error("expected peer to be protected only once")
+	}
+
+	if !cm.Unprotect(id, "unused") {
+		t.Error("expected peer to continue to be protected")
+	}
+
+	if !cm.Unprotect(id, "unused2") {
+		t.Error("expected peer to continue to be protected")
+	}
+
+	if cm.Unprotect(id, "global") {
+		t.Error("expected peer to be unprotected")
+	}
+
+	if len(cm.protected) > 0 {
+		t.Error("expected no protections")
+	}
+}
+
+func TestUpsertTag(t *testing.T) {
+	cm := NewConnManager(1, 1, time.Duration(10*time.Minute))
+	not := cm.Notifee()
+	conn := randConn(t, nil)
+	rp := conn.RemotePeer()
+
+	// this is an early tag, before the Connected notification arrived.
+	cm.UpsertTag(rp, "tag", func(v int) int { return v + 1 })
+	if len(cm.segments.get(rp).peers[rp].tags) != 1 {
+		t.Fatal("expected a tag")
+	}
+	if cm.segments.get(rp).peers[rp].value != 1 {
+		t.Fatal("expected a tag value of 1")
+	}
+
+	// now let's notify the connection.
+	not.Connected(nil, conn)
+
+	cm.UpsertTag(rp, "tag", func(v int) int { return v + 1 })
+	if len(cm.segments.get(rp).peers[rp].tags) != 1 {
+		t.Fatal("expected a tag")
+	}
+	if cm.segments.get(rp).peers[rp].value != 2 {
+		t.Fatal("expected a tag value of 2")
+	}
+
+	cm.UpsertTag(rp, "tag", func(v int) int { return v - 1 })
+	if len(cm.segments.get(rp).peers[rp].tags) != 1 {
+		t.Fatal("expected a tag")
+	}
+	if cm.segments.get(rp).peers[rp].value != 1 {
+		t.Fatal("expected a tag value of 1")
+	}
+}
+
+func TestTemporaryEntriesClearedFirst(t *testing.T) {
+	cm := NewConnManager(1, 1, 0)
+
+	id := tu.RandPeerIDFatal(t)
+	cm.TagPeer(id, "test", 20)
+
+	if cm.GetTagInfo(id).Value != 20 {
+		t.Fatal("expected an early tag with value 20")
+	}
+
+	not := cm.Notifee()
+	conn1, conn2 := randConn(t, nil), randConn(t, nil)
+	not.Connected(nil, conn1)
+	not.Connected(nil, conn2)
+
+	cm.TrimOpenConns(context.Background())
+	if cm.GetTagInfo(id) != nil {
+		t.Fatal("expected no temporary tags after trimming")
+	}
+}
+
+func TestTemporaryEntryConvertedOnConnection(t *testing.T) {
+	cm := NewConnManager(1, 1, 0)
+
+	conn := randConn(t, nil)
+	cm.TagPeer(conn.RemotePeer(), "test", 20)
+
+	ti := cm.segments.get(conn.RemotePeer()).peers[conn.RemotePeer()]
+
+	if ti.value != 20 || !ti.temp {
+		t.Fatal("expected a temporary tag with value 20")
+	}
+
+	not := cm.Notifee()
+	not.Connected(nil, conn)
+
+	if ti.value != 20 || ti.temp {
+		t.Fatal("expected a non-temporary tag with value 20")
+	}
+}
--- a/beacon-chain/p2p/dial_relay_node.go
+++ b/beacon-chain/p2p/dial_relay_node.go
@@ -5,13 +5,12 @@ import (

 	"github.com/libp2p/go-libp2p-core/host"
 	peerstore "github.com/libp2p/go-libp2p-peerstore"
-	"github.com/multiformats/go-multiaddr"
 	"go.opencensus.io/trace"
 )

 // MakePeer from multiaddress string.
 func MakePeer(addr string) (*peerstore.PeerInfo, error) {
-	maddr, err := multiaddr.NewMultiaddr(addr)
+	maddr, err := multiAddrFromString(addr)
 	if err != nil {
 		return nil, err
 	}
--- a/beacon-chain/p2p/handshake.go
+++ b/beacon-chain/p2p/handshake.go
@@ -41,7 +41,10 @@ func (s *Service) AddConnectionHandler(reqFunc func(ctx context.Context, id peer
 				if err := reqFunc(ctx, conn.RemotePeer()); err != nil && err != io.EOF {
 					log.WithError(err).Debug("Could not send successful hello rpc request")
 					if err.Error() == "protocol not supported" {
+						// This is only to ensure the smooth running of our testnets. This will not be
+						// used in production.
 						log.Debug("Not disconnecting peer with unsupported protocol. This may be the DHT node or relay.")
+						s.host.ConnManager().Protect(conn.RemotePeer(), "relay/bootnode")
 						return
 					}
 					if err := s.Disconnect(conn.RemotePeer()); err != nil {
--- a/beacon-chain/p2p/options.go
+++ b/beacon-chain/p2p/options.go
@@ -7,10 +7,10 @@ import (
 	"time"

 	"github.com/libp2p/go-libp2p"
-	connmgr "github.com/libp2p/go-libp2p-connmgr"
 	filter "github.com/libp2p/go-maddr-filter"
 	"github.com/multiformats/go-multiaddr"
 	ma "github.com/multiformats/go-multiaddr"
+	"github.com/prysmaticlabs/prysm/beacon-chain/p2p/connmgr"
 )

 // buildOptions for the libp2p host.
--- a/beacon-chain/p2p/service.go
+++ b/beacon-chain/p2p/service.go
@@ -130,6 +130,11 @@ func (s *Service) Start() {
 		if err := dialRelayNode(s.ctx, s.host, s.cfg.RelayNodeAddr); err != nil {
 			log.WithError(err).Errorf("Could not dial relay node")
 		}
+		peer, err := MakePeer(s.cfg.RelayNodeAddr)
+		if err != nil {
+			log.WithError(err).Errorf("Could not create peer")
+		}
+		s.host.ConnManager().Protect(peer.ID, "relay")
 	}

 	if len(s.cfg.Discv5BootStrapAddr) != 0 && !s.cfg.NoDiscovery {
@@ -164,6 +169,11 @@ func (s *Service) Start() {
 				s.startupErr = err
 				return
 			}
+			peer, err := MakePeer(addr)
+			if err != nil {
+				log.WithError(err).Errorf("Could not create peer")
+			}
+			s.host.ConnManager().Protect(peer.ID, "bootnode")
 		}
 		bcfg := kaddht.DefaultBootstrapConfig
 		bcfg.Period = time.Duration(30 * time.Second)