swarm: return a more meaningful error when dialing QUIC draft-29 (#2524)

* swarm: return a more meaningful error when dialing QUIC draft-29

* Apply suggestions from code review

Co-authored-by: Jorropo <jorropo.pgm@gmail.com>

* Update p2p/net/swarm/swarm_dial.go

* fix

* better types

---------

Co-authored-by: Jorropo <jorropo.pgm@gmail.com>

p2p/net/swarm/dial_test.go

@@ -642,3 +642,12 @@ func TestDialSelf(t *testing.T) {
 	_, err := s1.DialPeer(context.Background(), s1.LocalPeer())
 	require.ErrorIs(t, err, swarm.ErrDialToSelf, "expected error from self dial")
 }
+
+func TestDialQUICDraft29(t *testing.T) {
+	s := makeDialOnlySwarm(t)
+	id := testutil.RandPeerIDFatal(t)
+	s.Peerstore().AddAddr(id, ma.StringCast("/ip4/127.0.0.1/udp/1234/quic"), time.Hour)
+	_, err := s.DialPeer(context.Background(), id)
+	require.ErrorIs(t, err, swarm.ErrQUICDraft29)
+	require.ErrorIs(t, err, swarm.ErrNoTransport)
+}

p2p/net/swarm/swarm_dial.go

@@ -14,8 +14,10 @@ import (
 	"github.com/libp2p/go-libp2p/core/peer"
 	"github.com/libp2p/go-libp2p/core/peerstore"
 	"github.com/libp2p/go-libp2p/core/transport"
+
 	ma "github.com/multiformats/go-multiaddr"
 	madns "github.com/multiformats/go-multiaddr-dns"
+	mafmt "github.com/multiformats/go-multiaddr-fmt"
 	manet "github.com/multiformats/go-multiaddr/net"
 )
 
@@ -65,6 +67,19 @@ var (
 	ErrGaterDisallowedConnection = errors.New("gater disallows connection to peer")
 )
 
+// ErrQUICDraft29 wraps ErrNoTransport and provide a more meaningful error message
+var ErrQUICDraft29 errQUICDraft29
+
+type errQUICDraft29 struct{}
+
+func (errQUICDraft29) Error() string {
+	return "QUIC draft-29 has been removed, QUIC (RFC 9000) is accessible with /quic-v1"
+}
+
+func (errQUICDraft29) Unwrap() error {
+	return ErrNoTransport
+}
+
 // DialAttempts governs how many times a goroutine will try to dial a given peer.
 // Note: this is down to one, as we have _too many dials_ atm. To add back in,
 // add loop back in Dial(.)
@@ -407,6 +422,8 @@ func (s *Swarm) nonProxyAddr(addr ma.Multiaddr) bool {
 	return !t.Proxy()
 }
 
+var quicDraft29DialMatcher = mafmt.And(mafmt.IP, mafmt.Base(ma.P_UDP), mafmt.Base(ma.P_QUIC))
+
 // filterKnownUndialables takes a list of multiaddrs, and removes those
 // that we definitely don't want to dial: addresses configured to be blocked,
 // IPv6 link-local addresses, addresses without a dial-capable transport,
@@ -435,7 +452,13 @@ func (s *Swarm) filterKnownUndialables(p peer.ID, addrs []ma.Multiaddr) (goodAdd
 	// filter addresses with no transport
 	addrs = ma.FilterAddrs(addrs, func(a ma.Multiaddr) bool {
 		if s.TransportForDialing(a) == nil {
-			addrErrs = append(addrErrs, TransportError{Address: a, Cause: ErrNoTransport})
+			e := ErrNoTransport
+			// We used to support QUIC draft-29 for a long time.
+			// Provide a more useful error when attempting to dial a QUIC draft-29 address.
+			if quicDraft29DialMatcher.Matches(a) {
+				e = ErrQUICDraft29
+			}
+			addrErrs = append(addrErrs, TransportError{Address: a, Cause: e})
 			return false
 		}
 		return true