swarm: don't dial unspecified addresses (#2560)

* swarm: don't dial unspecified addresses

* add test

Author: sukunrt

p2p/net/swarm/swarm_dial.go

@@ -475,6 +475,14 @@ func (s *Swarm) filterKnownUndialables(p peer.ID, addrs []ma.Multiaddr) (goodAdd
 	}
 
 	return ma.FilterAddrs(addrs,
+		// Linux and BSD treat an unspecified address when dialing as a localhost address.
+		// Windows doesn't support this. We filter all such addresses out because peers
+		// listening on unspecified addresses will advertise more specific addresses.
+		// https://unix.stackexchange.com/a/419881
+		// https://superuser.com/a/1755455
+		func(addr ma.Multiaddr) bool {
+			return !manet.IsIPUnspecified(addr)
+		},
 		func(addr ma.Multiaddr) bool {
 			if ma.Contains(ourAddrs, addr) {
 				addrErrs = append(addrErrs, TransportError{Address: addr, Cause: ErrDialToSelf})

p2p/net/swarm/swarm_dial_test.go

@@ -277,6 +277,9 @@ func TestAddrsForDialFiltering(t *testing.T) {
 	t1 := ma.StringCast("/ip4/1.2.3.4/tcp/1")
 	ws1 := ma.StringCast("/ip4/1.2.3.4/tcp/1/ws")
 
+	unSpecQ := ma.StringCast("/ip4/0.0.0.0/udp/2/quic-v1")
+	unSpecT := ma.StringCast("/ip6/::/tcp/2/")
+
 	resolver, err := madns.NewResolver(madns.WithDefaultResolver(&madns.MockResolver{}))
 	require.NoError(t, err)
 	s := newTestSwarmWithResolver(t, resolver)
@@ -307,6 +310,11 @@ func TestAddrsForDialFiltering(t *testing.T) {
 			input:  append([]ma.Multiaddr{q1}, ourAddrs...),
 			output: []ma.Multiaddr{q1},
 		},
+		{
+			name:   "unspecified-filtered",
+			input:  []ma.Multiaddr{q1v1, t1, unSpecQ, unSpecT},
+			output: []ma.Multiaddr{q1v1, t1},
+		},
 	}
 
 	ctx := context.Background()