Hack asn-util. Ref: https://github.com/libp2p/go-libp2p/issues/2664

deps.bzl

@@ -2578,8 +2578,16 @@ def prysm_deps():
         version = "v0.27.8",
     )
     go_repository(
+        # This library accounts for a significant wall time in production builds. It is not used by
+        # Prysm at this time.
+        # See https://github.com/libp2p/go-libp2p/issues/2664
         name = "com_github_libp2p_go_libp2p_asn_util",
+        build_directives = [
+            "gazelle:exclude ipv6_asn_map.gen.go",
+        ],
         importpath = "github.com/libp2p/go-libp2p-asn-util",
+        patch_args = ["-p1"],
+        patches = ["//third_party:com_github_libp2p_go_libp2p_asn_util.patch"],
         sum = "h1:gMDcMyYiZKkocGXDQ5nsUQyquC9+H+iLEQHwOCZ7s8s=",
         version = "v0.3.0",
     )

third_party/com_github_libp2p_go_libp2p_asn_util.patch

@@ -0,0 +1,26 @@
+diff --git a/asn.go b/asn.go
+index 490b4a2..fcfb0da 100644
+--- a/asn.go
++++ b/asn.go
+@@ -51,20 +51,7 @@ func (a *asnStore) AsnForIPv6(ip net.IP) (string, error) {
+ }
+ 
+ func newAsnStore() (*asnStore, error) {
+-	cr := cidranger.NewPCTrieRanger()
+-
+-	for _, v := range ipv6CidrToAsnPairList {
+-		_, nn, err := net.ParseCIDR(v.cidr)
+-		if err != nil {
+-			return nil, fmt.Errorf("failed to parse CIDR %s: %w", v.cidr, err)
+-		}
+-
+-		if err := cr.Insert(&networkWithAsn{*nn, v.asn}); err != nil {
+-			return nil, fmt.Errorf("failed to insert CIDR %s in Trie store: %w", v.cidr, err)
+-		}
+-	}
+-
+-	return &asnStore{cr}, nil
++	return nil, errors.New("asnutil store is empty because it is never used and causes significant build delays")
+ }
+ 
+ // lazyAsnStore builds the underlying trie on first call to AsnForIPv6.