From 8986bf4b14c925294632d7cfddc6f31dbb24ba02 Mon Sep 17 00:00:00 2001
From: sukun <sukunrt@gmail.com>
Date: Mon, 24 Mar 2025 23:32:44 +0530
Subject: [PATCH] autonatv2: explicitly handle dns addrs

We do allow dns addrs for autonatv2. This function handles them
correcly but the comment is wrong and the handling is accidental.
Make it explicity.
---
 p2p/protocol/autonatv2/server.go      | 5 ++++-
 p2p/protocol/autonatv2/server_test.go | 7 +++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/p2p/protocol/autonatv2/server.go b/p2p/protocol/autonatv2/server.go
index dafac4dfe2..3c6d0d53a6 100644
--- a/p2p/protocol/autonatv2/server.go
+++ b/p2p/protocol/autonatv2/server.go
@@ -522,6 +522,9 @@ func amplificationAttackPrevention(observedAddr, dialAddr ma.Multiaddr) bool {
 	if err != nil {
 		return true
 	}
-	dialIP, _ := manet.ToIP(dialAddr) // must be an IP multiaddr
+	dialIP, err := manet.ToIP(dialAddr) // can be dns addr
+	if err != nil {
+		return true
+	}
 	return !observedIP.Equal(dialIP)
 }
diff --git a/p2p/protocol/autonatv2/server_test.go b/p2p/protocol/autonatv2/server_test.go
index f92396fb16..65b1b131b9 100644
--- a/p2p/protocol/autonatv2/server_test.go
+++ b/p2p/protocol/autonatv2/server_test.go
@@ -588,6 +588,13 @@ func TestDefaultAmplificationAttackPrevention(t *testing.T) {
 
 	t2 := ma.StringCast("/ip4/1.1.1.1/tcp/1235") // different IP
 	require.True(t, amplificationAttackPrevention(q2, t2))
+
+	// always ask dial data for dns addrs
+	d1 := ma.StringCast("/dns/localhost/udp/1/quic-v1")
+	d2 := ma.StringCast("/dnsaddr/libp2p.io/tcp/1")
+	require.True(t, amplificationAttackPrevention(d1, t1))
+	require.True(t, amplificationAttackPrevention(d2, t1))
+
 }
 
 func FuzzServerDialRequest(f *testing.F) {