From 912a8ee9e02662eec79690dc0c9ff6510b936dda Mon Sep 17 00:00:00 2001
From: sukun <sukunrt@gmail.com>
Date: Mon, 25 Sep 2023 18:35:23 +0530
Subject: [PATCH] autorelay: advertise /webrtc addresses on relay reservation

---
 p2p/host/autorelay/autorelay_test.go | 46 ++++++++++++++++++++++++++++
 p2p/host/autorelay/relay_finder.go   | 18 +++++++++++
 2 files changed, 64 insertions(+)

diff --git a/p2p/host/autorelay/autorelay_test.go b/p2p/host/autorelay/autorelay_test.go
index 410f8cb6dc..8f7e7ee6d3 100644
--- a/p2p/host/autorelay/autorelay_test.go
+++ b/p2p/host/autorelay/autorelay_test.go
@@ -517,3 +517,49 @@ func TestNoBusyLoop0MinInterval(t *testing.T) {
 	val := atomic.LoadUint64(&calledTimes)
 	require.Less(t, val, uint64(2))
 }
+
+func TestRelayAddrs(t *testing.T) {
+	const numCandidates = 3
+	var called bool
+	peerChan := make(chan peer.AddrInfo, numCandidates)
+	for i := 0; i < numCandidates; i++ {
+		r := newRelay(t)
+		t.Cleanup(func() { r.Close() })
+		peerChan <- peer.AddrInfo{ID: r.ID(), Addrs: r.Addrs()}
+	}
+	close(peerChan)
+
+	h := newPrivateNode(t,
+		func(_ context.Context, num int) <-chan peer.AddrInfo {
+			require.False(t, called, "expected the peer source callback to only have been called once")
+			called = true
+			require.Equal(t, numCandidates, num)
+			return peerChan
+		},
+		autorelay.WithMaxCandidates(numCandidates),
+		autorelay.WithNumRelays(1),
+		autorelay.WithBootDelay(0),
+		autorelay.WithMinInterval(time.Hour),
+	)
+	defer h.Close()
+
+	require.Eventually(
+		t,
+		func() bool {
+			if numRelays(h) <= 0 {
+				return false
+			}
+			addrs := h.Addrs()
+			var foundCircuit, foundWebRTC bool
+			for _, addr := range addrs {
+				_, cerr := addr.ValueForProtocol(ma.P_CIRCUIT)
+				_, werr := addr.ValueForProtocol(ma.P_WEBRTC)
+				foundCircuit = foundCircuit || cerr == nil
+				foundWebRTC = foundWebRTC || (cerr == nil && werr == nil)
+			}
+			return foundCircuit && foundWebRTC
+		},
+		5*time.Second,
+		100*time.Millisecond,
+	)
+}
diff --git a/p2p/host/autorelay/relay_finder.go b/p2p/host/autorelay/relay_finder.go
index ef79950b7b..aa5e20bfef 100644
--- a/p2p/host/autorelay/relay_finder.go
+++ b/p2p/host/autorelay/relay_finder.go
@@ -17,6 +17,7 @@ import (
 	"github.com/libp2p/go-libp2p/p2p/host/eventbus"
 	circuitv2 "github.com/libp2p/go-libp2p/p2p/protocol/circuitv2/client"
 	circuitv2_proto "github.com/libp2p/go-libp2p/p2p/protocol/circuitv2/proto"
+	libp2pwebrtcprivate "github.com/libp2p/go-libp2p/p2p/transport/webrtcprivate"
 
 	ma "github.com/multiformats/go-multiaddr"
 	manet "github.com/multiformats/go-multiaddr/net"
@@ -737,9 +738,15 @@ func (rf *relayFinder) relayAddrs(addrs []ma.Multiaddr) []ma.Multiaddr {
 		addrs := cleanupAddressSet(rf.host.Peerstore().Addrs(p))
 		relayAddrCnt += len(addrs)
 		circuit := ma.StringCast(fmt.Sprintf("/p2p/%s/p2p-circuit", p))
+		webrtc := libp2pwebrtcprivate.WebRTCAddr
 		for _, addr := range addrs {
 			pub := addr.Encapsulate(circuit)
 			raddrs = append(raddrs, pub)
+			if isBrowserDialableAddr(addr) {
+				waddr := pub.Encapsulate(webrtc)
+				raddrs = append(raddrs, waddr)
+				relayAddrCnt++
+			}
 		}
 	}
 
@@ -808,3 +815,14 @@ func (rf *relayFinder) resetMetrics() {
 	rf.metricsTracer.RelayAddressCount(0)
 	rf.metricsTracer.ScheduledWorkUpdated(&scheduledWorkTimes{})
 }
+
+var browserProtocols []int = []int{ma.P_WEBTRANSPORT, ma.P_WEBRTC_DIRECT, ma.P_WS, ma.P_WSS}
+
+func isBrowserDialableAddr(addr ma.Multiaddr) bool {
+	for _, p := range browserProtocols {
+		if _, err := addr.ValueForProtocol(p); err == nil {
+			return true
+		}
+	}
+	return false
+}