From 5d0c8806bccc3924e0adac601358749c20ec2afd Mon Sep 17 00:00:00 2001
From: Felix Lange <fjl@twurst.com>
Date: Tue, 21 May 2024 13:43:17 +0200
Subject: [PATCH] p2p/enode: support unspecified IP

---
 p2p/enode/node.go      | 16 +++++++++-------
 p2p/enode/node_test.go | 19 +++++++++++++++++++
 2 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/p2p/enode/node.go b/p2p/enode/node.go
index 180cab34fb..e7fe0e0ace 100644
--- a/p2p/enode/node.go
+++ b/p2p/enode/node.go
@@ -83,19 +83,21 @@ func newNodeWithID(r *enr.Record, id ID) *Node {
 
 // validIP reports whether 'ip' is a valid node endpoint IP address.
 func validIP(ip netip.Addr) bool {
-	return ip.IsValid() && !ip.IsUnspecified() && !ip.IsMulticast()
+	return ip.IsValid() && !ip.IsMulticast()
 }
 
 func localityScore(ip netip.Addr) int {
 	switch {
-	case ip.IsLoopback():
+	case ip.IsUnspecified():
 		return 0
-	case ip.IsLinkLocalUnicast():
+	case ip.IsLoopback():
 		return 1
-	case ip.IsPrivate():
+	case ip.IsLinkLocalUnicast():
 		return 2
-	default:
+	case ip.IsPrivate():
 		return 3
+	default:
+		return 4
 	}
 }
 
@@ -184,7 +186,7 @@ func (n *Node) TCP() int {
 
 // UDPEndpoint returns the announced TCP endpoint.
 func (n *Node) UDPEndpoint() (netip.AddrPort, bool) {
-	if !n.ip.IsValid() || n.udp == 0 {
+	if !n.ip.IsValid() || n.ip.IsUnspecified() || n.udp == 0 {
 		return netip.AddrPort{}, false
 	}
 	return netip.AddrPortFrom(n.ip, n.udp), true
@@ -192,7 +194,7 @@ func (n *Node) UDPEndpoint() (netip.AddrPort, bool) {
 
 // TCPEndpoint returns the announced TCP endpoint.
 func (n *Node) TCPEndpoint() (netip.AddrPort, bool) {
-	if !n.ip.IsValid() || n.tcp == 0 {
+	if !n.ip.IsValid() || n.ip.IsUnspecified() || n.tcp == 0 {
 		return netip.AddrPort{}, false
 	}
 	return netip.AddrPortFrom(n.ip, n.udp), true
diff --git a/p2p/enode/node_test.go b/p2p/enode/node_test.go
index cac77099da..56e196e82e 100644
--- a/p2p/enode/node_test.go
+++ b/p2p/enode/node_test.go
@@ -107,6 +107,15 @@ func TestNodeEndpoints(t *testing.T) {
 			}(),
 			wantIP: netip.MustParseAddr("127.0.0.1"),
 		},
+		{
+			name: "ipv4-only-unspecified",
+			node: func() *Node {
+				var r enr.Record
+				r.Set(enr.IPv4Addr(netip.MustParseAddr("0.0.0.0")))
+				return SignNull(&r, id)
+			}(),
+			wantIP: netip.MustParseAddr("0.0.0.0"),
+		},
 		{
 			name: "ipv4-only",
 			node: func() *Node {
@@ -138,6 +147,16 @@ func TestNodeEndpoints(t *testing.T) {
 			wantIP:  netip.MustParseAddr("2001::ff00:0042:8329"),
 			wantUDP: 30306,
 		},
+		{
+			name: "ipv4-unspecified-and-ipv6-loopback",
+			node: func() *Node {
+				var r enr.Record
+				r.Set(enr.IPv4Addr(netip.MustParseAddr("0.0.0.0")))
+				r.Set(enr.IPv6Addr(netip.MustParseAddr("::1")))
+				return SignNull(&r, id)
+			}(),
+			wantIP: netip.MustParseAddr("::1"),
+		},
 		{
 			name: "ipv4-private-and-ipv6-global",
 			node: func() *Node {