From 6ffd98d337da80e4b4d1567e90711d33f75aac7f Mon Sep 17 00:00:00 2001
From: Felix Lange <fjl@twurst.com>
Date: Thu, 30 May 2024 17:59:46 +0200
Subject: [PATCH] p2p/netutil: fixes for 4-in-6

---
 p2p/netutil/net.go      |  8 +++++++-
 p2p/netutil/net_test.go | 26 ++++++++++++++++++++------
 2 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/p2p/netutil/net.go b/p2p/netutil/net.go
index 9495a2af80..85c62cf5d4 100644
--- a/p2p/netutil/net.go
+++ b/p2p/netutil/net.go
@@ -145,6 +145,9 @@ func IsLAN(ip net.IP) bool {
 
 // IsLAN reports whether an IP is a local network address.
 func AddrIsLAN(ip netip.Addr) bool {
+	if ip.Is4In6() {
+		ip = netip.AddrFrom4(ip.As4())
+	}
 	if ip.IsLoopback() {
 		return true
 	}
@@ -160,10 +163,13 @@ func IsSpecialNetwork(ip net.IP) bool {
 // AddrIsSpecialNetwork reports whether an IP is located in a special-use network range
 // This includes broadcast, multicast and documentation addresses.
 func AddrIsSpecialNetwork(ip netip.Addr) bool {
+	if ip.Is4In6() {
+		ip = netip.AddrFrom4(ip.As4())
+	}
 	if ip.IsMulticast() {
 		return true
 	}
-	if ip.Is4() || ip.Is4In6() {
+	if ip.Is4() {
 		return special4.ContainsAddr(ip)
 	}
 	return special6.ContainsAddr(ip)
diff --git a/p2p/netutil/net_test.go b/p2p/netutil/net_test.go
index d9fcac8caf..569c7ac454 100644
--- a/p2p/netutil/net_test.go
+++ b/p2p/netutil/net_test.go
@@ -74,11 +74,11 @@ func TestParseNetlist(t *testing.T) {
 
 func TestNilNetListContains(t *testing.T) {
 	var list *Netlist
-	checkContains(t, list.Contains, nil, []string{"1.2.3.4"})
+	checkContains(t, list.Contains, list.ContainsAddr, nil, []string{"1.2.3.4"})
 }
 
 func TestIsLAN(t *testing.T) {
-	checkContains(t, IsLAN,
+	checkContains(t, IsLAN, AddrIsLAN,
 		[]string{ // included
 			"127.0.0.1",
 			"10.0.1.1",
@@ -88,18 +88,23 @@ func TestIsLAN(t *testing.T) {
 			"fe80::f4a1:8eff:fec5:9d9d",
 			"febf::ab32:2233",
 			"fc00::4",
+			// 4-in-6
+			"::ffff:127.0.0.1",
+			"::ffff:10.10.0.2",
 		},
 		[]string{ // excluded
 			"192.0.2.1",
 			"1.0.0.0",
 			"172.32.0.1",
 			"fec0::2233",
+			// 4-in-6
+			"::ffff:88.99.100.2",
 		},
 	)
 }
 
 func TestIsSpecialNetwork(t *testing.T) {
-	checkContains(t, IsSpecialNetwork,
+	checkContains(t, IsSpecialNetwork, AddrIsSpecialNetwork,
 		[]string{ // included
 			"0.0.0.0",
 			"0.2.0.8",
@@ -109,6 +114,9 @@ func TestIsSpecialNetwork(t *testing.T) {
 			"255.255.255.255",
 			"224.0.0.22", // IPv4 multicast
 			"ff05::1:3",  // IPv6 multicast
+			// 4-in-6
+			"::ffff:255.255.255.255",
+			"::ffff:192.0.2.1",
 		},
 		[]string{ // excluded
 			"192.0.3.1",
@@ -119,15 +127,21 @@ func TestIsSpecialNetwork(t *testing.T) {
 	)
 }
 
-func checkContains(t *testing.T, fn func(net.IP) bool, inc, exc []string) {
+func checkContains(t *testing.T, fn func(net.IP) bool, fn2 func(netip.Addr) bool, inc, exc []string) {
 	for _, s := range inc {
 		if !fn(parseIP(s)) {
-			t.Error("returned false for included address", s)
+			t.Error("returned false for included net.IP", s)
+		}
+		if !fn2(netip.MustParseAddr(s)) {
+			t.Error("returned false for included netip.Addr", s)
 		}
 	}
 	for _, s := range exc {
 		if fn(parseIP(s)) {
-			t.Error("returned true for excluded address", s)
+			t.Error("returned true for excluded net.IP", s)
+		}
+		if fn2(netip.MustParseAddr(s)) {
+			t.Error("returned true for excluded netip.Addr", s)
 		}
 	}
 }