correctly handle WebTransport addresses without certhashes

libp2p_test.go

@@ -17,6 +17,7 @@ import (
 	tls "github.com/libp2p/go-libp2p/p2p/security/tls"
 	quic "github.com/libp2p/go-libp2p/p2p/transport/quic"
 	"github.com/libp2p/go-libp2p/p2p/transport/tcp"
+	webtransport "github.com/libp2p/go-libp2p/p2p/transport/webtransport"
 
 	ma "github.com/multiformats/go-multiaddr"
 	"github.com/stretchr/testify/require"
@@ -289,3 +290,41 @@ func TestSecurityConstructor(t *testing.T) {
 	require.Contains(t, err.Error(), "failed to negotiate security protocol")
 	require.NoError(t, h2.Connect(context.Background(), ai))
 }
+
+func TestTransportConstructorWebTransport(t *testing.T) {
+	h, err := New(
+		Transport(webtransport.New),
+		DisableRelay(),
+	)
+	require.NoError(t, err)
+	defer h.Close()
+	require.NoError(t, h.Network().Listen(ma.StringCast("/ip4/127.0.0.1/udp/0/quic-v1/webtransport")))
+	err = h.Network().Listen(ma.StringCast("/ip4/127.0.0.1/udp/0/quic-v1/"))
+	require.Error(t, err)
+	require.Contains(t, err.Error(), swarm.ErrNoTransport.Error())
+}
+
+func TestTransportCustomAddressWebTransport(t *testing.T) {
+	customAddr, err := ma.NewMultiaddr("/ip4/1.2.3.4/udp/1234/quic-v1/webtransport")
+	if err != nil {
+		t.Fatal(err)
+	}
+	h, err := New(
+		Transport(webtransport.New),
+		DisableRelay(),
+		AddrsFactory(func(multiaddrs []ma.Multiaddr) []ma.Multiaddr {
+			return []ma.Multiaddr{customAddr}
+		}),
+	)
+	require.NoError(t, err)
+	defer h.Close()
+	require.NoError(t, h.Network().Listen(ma.StringCast("/ip4/127.0.0.1/udp/0/quic-v1/webtransport")))
+	addrs := h.Addrs()
+	require.Len(t, addrs, 1)
+	require.NotEqual(t, addrs[0], customAddr)
+	restOfAddr, lastComp := ma.SplitLast(addrs[0])
+	restOfAddr, secondToLastComp := ma.SplitLast(restOfAddr)
+	require.Equal(t, lastComp.Protocol().Code, ma.P_CERTHASH)
+	require.Equal(t, secondToLastComp.Protocol().Code, ma.P_CERTHASH)
+	require.True(t, restOfAddr.Equal(customAddr))
+}

options.go

@@ -262,6 +262,7 @@ func AddrsFactory(factory config.AddrsFactory) Option {
 		if cfg.AddrsFactory != nil {
 			return fmt.Errorf("cannot specify multiple address factories")
 		}
+
 		cfg.AddrsFactory = factory
 		return nil
 	}

p2p/host/basic/basic_host.go

@@ -18,6 +18,7 @@ import (
 	"github.com/libp2p/go-libp2p/core/peerstore"
 	"github.com/libp2p/go-libp2p/core/protocol"
 	"github.com/libp2p/go-libp2p/core/record"
+	"github.com/libp2p/go-libp2p/core/transport"
 	"github.com/libp2p/go-libp2p/p2p/host/autonat"
 	"github.com/libp2p/go-libp2p/p2p/host/eventbus"
 	"github.com/libp2p/go-libp2p/p2p/host/pstoremanager"
@@ -27,11 +28,13 @@ import (
 	"github.com/libp2p/go-libp2p/p2p/protocol/holepunch"
 	"github.com/libp2p/go-libp2p/p2p/protocol/identify"
 	"github.com/libp2p/go-libp2p/p2p/protocol/ping"
+	libp2pwebtransport "github.com/libp2p/go-libp2p/p2p/transport/webtransport"
 	"github.com/prometheus/client_golang/prometheus"
 
 	"github.com/libp2p/go-netroute"
 
 	logging "github.com/ipfs/go-log/v2"
+	"github.com/multiformats/go-multiaddr"
 	ma "github.com/multiformats/go-multiaddr"
 	madns "github.com/multiformats/go-multiaddr-dns"
 	manet "github.com/multiformats/go-multiaddr/net"
@@ -760,7 +763,48 @@ func (h *BasicHost) ConnManager() connmgr.ConnManager {
 // Addrs returns listening addresses that are safe to announce to the network.
 // The output is the same as AllAddrs, but processed by AddrsFactory.
 func (h *BasicHost) Addrs() []ma.Multiaddr {
-	return h.AddrsFactory(h.AllAddrs())
+	type transportForListeninger interface {
+		TransportForListening(a ma.Multiaddr) transport.Transport
+	}
+	type addCertHasher interface {
+		AddCertHashes(m ma.Multiaddr) ma.Multiaddr
+	}
+
+	addrs := h.AddrsFactory(h.AllAddrs())
+
+	s, ok := h.Network().(transportForListeninger)
+	if !ok {
+		return addrs
+	}
+
+	for i, addr := range addrs {
+		if ok, n := libp2pwebtransport.IsWebtransportMultiaddr(addr); ok && n == 0 {
+			t := s.TransportForListening(addr)
+			tpt, ok := t.(addCertHasher)
+			if !ok {
+				continue
+			}
+			addrs[i] = tpt.AddCertHashes(addr)
+		}
+	}
+	return addrs
+}
+
+// NormalizeMultiaddr returns a multiaddr suitable for equality checks.
+// If the multiaddr is a webtransport component, it removes the certhashes.
+func (h *BasicHost) NormalizeMultiaddr(addr ma.Multiaddr) ma.Multiaddr {
+	if ok, n := libp2pwebtransport.IsWebtransportMultiaddr(addr); ok && n > 0 {
+		var firstCerthash ma.Multiaddr
+		multiaddr.ForEach(addr, func(c ma.Component) bool {
+			if c.Protocol().Code == ma.P_CERTHASH {
+				firstCerthash = &c
+				return false
+			}
+			return true
+		})
+		return addr.Decapsulate(firstCerthash)
+	}
+	return addr
 }
 
 // mergeAddrs merges input address lists, leave only unique addresses

p2p/protocol/identify/obsaddr.go

@@ -356,6 +356,10 @@ func (oas *ObservedAddrManager) removeConn(conn network.Conn) {
 	oas.activeConnsMu.Unlock()
 }
 
+type normalizeMultiaddrer interface {
+	NormalizeMultiaddr(addr ma.Multiaddr) ma.Multiaddr
+}
+
 func (oas *ObservedAddrManager) maybeRecordObservation(conn network.Conn, observed ma.Multiaddr) {
 	// First, determine if this observation is even worth keeping...
 
@@ -375,16 +379,40 @@ func (oas *ObservedAddrManager) maybeRecordObservation(conn network.Conn, observ
 		return
 	}
 
+	normalizer, canNormalize := oas.host.(normalizeMultiaddrer)
+
+	if canNormalize {
+		for i, a := range ifaceaddrs {
+			ifaceaddrs[i] = normalizer.NormalizeMultiaddr(a)
+		}
+	}
+
 	local := conn.LocalMultiaddr()
+	if canNormalize {
+		local = normalizer.NormalizeMultiaddr(local)
+	}
 	if !ma.Contains(ifaceaddrs, local) && !ma.Contains(oas.host.Network().ListenAddresses(), local) {
 		// not in our list
 		return
 	}
 
+	hostAddrs := oas.host.Addrs()
+	if canNormalize {
+		for i, a := range hostAddrs {
+			hostAddrs[i] = normalizer.NormalizeMultiaddr(a)
+		}
+	}
+	listenAddrs := oas.host.Network().ListenAddresses()
+	if canNormalize {
+		for i, a := range listenAddrs {
+			listenAddrs[i] = normalizer.NormalizeMultiaddr(a)
+		}
+	}
+
 	// We should reject the connection if the observation doesn't match the
 	// transports of one of our advertised addresses.
-	if !HasConsistentTransport(observed, oas.host.Addrs()) &&
-		!HasConsistentTransport(observed, oas.host.Network().ListenAddresses()) {
+	if !HasConsistentTransport(observed, hostAddrs) &&
+		!HasConsistentTransport(observed, listenAddrs) {
 		log.Debugw(
 			"observed multiaddr doesn't match the transports of any announced addresses",
 			"from", conn.RemoteMultiaddr(),

p2p/protocol/identify/obsaddr_test.go

@@ -83,10 +83,14 @@ func (h *harness) observeInbound(observed ma.Multiaddr, observer peer.ID) networ
 }
 
 func newHarness(t *testing.T) harness {
+	return newHarnessWithMa(t, ma.StringCast("/ip4/127.0.0.1/tcp/10086"))
+}
+
+func newHarnessWithMa(t *testing.T, listenAddr ma.Multiaddr) harness {
 	mn := mocknet.New()
 	sk, _, err := ic.GenerateECDSAKeyPair(rand.Reader)
 	require.NoError(t, err)
-	h, err := mn.AddPeer(sk, ma.StringCast("/ip4/127.0.0.1/tcp/10086"))
+	h, err := mn.AddPeer(sk, listenAddr)
 	require.NoError(t, err)
 	oas, err := identify.NewObservedAddrManager(h)
 	require.NoError(t, err)
@@ -408,3 +412,25 @@ func TestEmitNATDeviceTypeCone(t *testing.T) {
 		t.Fatal("did not get Cone NAT event")
 	}
 }
+
+func TestObserveWebtransport(t *testing.T) {
+	listenAddr := ma.StringCast("/ip4/1.2.3.4/udp/9999/quic-v1/webtransport/certhash/uEgNmb28")
+	observedAddr := ma.StringCast("/ip4/1.2.3.4/udp/1231/quic-v1/webtransport")
+
+	harness := newHarnessWithMa(t, listenAddr)
+
+	pb1 := harness.add(ma.StringCast("/ip4/1.2.3.6/udp/1236/quic-v1/webtransport"))
+	pb2 := harness.add(ma.StringCast("/ip4/1.2.3.7/udp/1237/quic-v1/webtransport"))
+	pb3 := harness.add(ma.StringCast("/ip4/1.2.3.8/udp/1237/quic-v1/webtransport"))
+	pb4 := harness.add(ma.StringCast("/ip4/1.2.3.9/udp/1237/quic-v1/webtransport"))
+	pb5 := harness.add(ma.StringCast("/ip4/1.2.3.10/udp/1237/quic-v1/webtransport"))
+
+	harness.observe(observedAddr, pb1)
+	harness.observe(observedAddr, pb2)
+	harness.observe(observedAddr, pb3)
+	harness.observe(observedAddr, pb4)
+	harness.observe(observedAddr, pb5)
+
+	require.Equal(t, 1, len(harness.oas.Addrs()))
+	require.Equal(t, "/ip4/1.2.3.4/udp/1231/quic-v1/webtransport", harness.oas.Addrs()[0].String())
+}

p2p/transport/webtransport/multiaddr.go

@@ -7,16 +7,13 @@ import (
 	"strconv"
 
 	ma "github.com/multiformats/go-multiaddr"
-	mafmt "github.com/multiformats/go-multiaddr-fmt"
 	manet "github.com/multiformats/go-multiaddr/net"
 	"github.com/multiformats/go-multibase"
 	"github.com/multiformats/go-multihash"
 )
 
 var webtransportMA = ma.StringCast("/quic-v1/webtransport")
 
-var webtransportMatcher = mafmt.And(mafmt.IP, mafmt.Base(ma.P_UDP), mafmt.Base(ma.P_QUIC_V1), mafmt.Base(ma.P_WEBTRANSPORT))
-
 func toWebtransportMultiaddr(na net.Addr) (ma.Multiaddr, error) {
 	addr, err := manet.FromNetAddr(na)
 	if err != nil {
@@ -78,3 +75,40 @@ func addrComponentForCert(hash []byte) (ma.Multiaddr, error) {
 	}
 	return ma.NewComponent(ma.ProtocolWithCode(ma.P_CERTHASH).Name, certStr)
 }
+
+// IsWebtransportMultiaddrWithCerthash returns true if the given multiaddr is a
+// well formed webtransport multiaddr. Returns the number of certhashes found.
+func IsWebtransportMultiaddr(multiaddr ma.Multiaddr) (bool, int) {
+	const (
+		init = iota
+		foundUDP
+		foundQuicV1
+		foundWebTransport
+	)
+	state := init
+	certhashCount := 0
+
+	ma.ForEach(multiaddr, func(c ma.Component) bool {
+		if c.Protocol().Code == ma.P_QUIC_V1 && state == init {
+			state = foundUDP
+		}
+		if c.Protocol().Code == ma.P_QUIC_V1 && state == foundUDP {
+			state = foundQuicV1
+		}
+		if c.Protocol().Code == ma.P_WEBTRANSPORT && state == foundQuicV1 {
+			state = foundWebTransport
+		}
+		if c.Protocol().Code == ma.P_CERTHASH && state == foundWebTransport {
+			certhashCount++
+		}
+		return true
+	})
+	return state == foundWebTransport, certhashCount
+}
+
+// IsWebtransportMultiaddrWithCerthash returns true if the given multiaddr is a
+// well formed webtransport multiaddr with a certificate hash.
+func IsWebtransportMultiaddrWithCerthash(multiaddr ma.Multiaddr) bool {
+	ok, n := IsWebtransportMultiaddr(multiaddr)
+	return ok && n > 0
+}

p2p/transport/webtransport/multiaddr_test.go

@@ -103,3 +103,29 @@ func TestWebtransportResolve(t *testing.T) {
 		require.Error(t, err)
 	})
 }
+
+func TestIsWebtransportMultiaddrWithCerthash(t *testing.T) {
+	fooHash := encodeCertHash(t, []byte("foo"), multihash.SHA2_256, multibase.Base58BTC)
+	barHash := encodeCertHash(t, []byte("bar"), multihash.SHA2_256, multibase.Base58BTC)
+
+	testCases := []struct {
+		addr          string
+		want          bool
+		certhashCount int
+	}{
+		{addr: "/ip4/1.2.3.4/udp/60042/quic-v1/webtransport", want: true},
+		{addr: "/ip4/1.2.3.4/udp/60042/quic-v1/webtransport/certhash/" + fooHash, want: true, certhashCount: 1},
+		{addr: "/ip4/1.2.3.4/udp/60042/quic-v1/webtransport/certhash/" + fooHash + "/certhash/" + barHash, want: true, certhashCount: 2},
+		{addr: "/dns4/example.com/udp/60042/quic-v1/webtransport/certhash/" + fooHash, want: true, certhashCount: 1},
+		{addr: "/dns4/example.com/udp/60042/webrtc/certhash/" + fooHash, want: false},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.addr, func(t *testing.T) {
+			got, n := IsWebtransportMultiaddr(ma.StringCast(tc.addr))
+			require.Equal(t, tc.want, got)
+			require.Equal(t, tc.certhashCount, n)
+			require.Equal(t, tc.want && n > 0, IsWebtransportMultiaddrWithCerthash(ma.StringCast(tc.addr)))
+		})
+	}
+}

p2p/transport/webtransport/transport.go

@@ -286,23 +286,13 @@ func decodeCertHashesFromProtobuf(b [][]byte) ([]multihash.DecodedMultihash, err
 }
 
 func (t *transport) CanDial(addr ma.Multiaddr) bool {
-	var numHashes int
-	ma.ForEach(addr, func(c ma.Component) bool {
-		if c.Protocol().Code == ma.P_CERTHASH {
-			numHashes++
-		}
-		return true
-	})
-	// Remove the /certhash components from the multiaddr.
-	// If the multiaddr doesn't contain any certhashes, the node might have a CA-signed certificate.
-	for i := 0; i < numHashes; i++ {
-		addr, _ = ma.SplitLast(addr)
-	}
-	return webtransportMatcher.Matches(addr)
+	ok, _ := IsWebtransportMultiaddr(addr)
+	return ok
 }
 
 func (t *transport) Listen(laddr ma.Multiaddr) (tpt.Listener, error) {
-	if !webtransportMatcher.Matches(laddr) {
+	isWebTransport, _ := IsWebtransportMultiaddr(laddr)
+	if !isWebTransport {
 		return nil, fmt.Errorf("cannot listen on non-WebTransport addr: %s", laddr)
 	}
 	if t.staticTLSConf == nil {
@@ -410,3 +400,10 @@ func (t *transport) Resolve(_ context.Context, maddr ma.Multiaddr) ([]ma.Multiad
 	}
 	return []ma.Multiaddr{beforeQuicMA.Encapsulate(quicComponent).Encapsulate(sniComponent).Encapsulate(afterQuicMA)}, nil
 }
+
+func (t *transport) AddCertHashes(m ma.Multiaddr) ma.Multiaddr {
+	if t.certManager == nil {
+		return m
+	}
+	return m.Encapsulate(t.certManager.AddrComponent())
+}