Use webrtc local addr for webrtc conn peer priority

WebRTC conns are providing the correct IP for peer priority calculations, so use that instead of trying to guess (which doesn't work if there are no regular conn listeners attached to the Client.

(cherry picked from commit e86bb5fee3958dc90a3d012469b1352005d6c9ad)

bep40_test.go

@@ -20,6 +20,10 @@ func TestBep40Priority(t *testing.T) {
 		IpPort{IP: net.ParseIP("123.213.32.10"), Port: 0},
 		IpPort{IP: net.ParseIP("123.213.32.234"), Port: 0},
 	))
+	assert.Equal(t, peerPriority(0x2b41d456), bep40PriorityIgnoreError(
+		IpPort{IP: net.ParseIP("206.248.98.111"), Port: 0},
+		IpPort{IP: net.ParseIP("142.147.89.224"), Port: 0},
+	))
 	assert.EqualValues(t, "\x00\x00\x00\x00", func() []byte {
 		b, _ := bep40PriorityBytes(
 			IpPort{IP: net.ParseIP("123.213.32.234"), Port: 0},

client.go

@@ -551,8 +551,16 @@ func (cl *Client) incomingConnection(nc net.Conn) {
 	if tc, ok := nc.(*net.TCPConn); ok {
 		tc.SetLinger(0)
 	}
-	c := cl.newConnection(nc, false, nc.RemoteAddr(), nc.RemoteAddr().Network(),
-		regularNetConnPeerConnConnString(nc))
+	remoteAddr, _ := tryIpPortFromNetAddr(nc.RemoteAddr())
+	c := cl.newConnection(
+		nc,
+		newConnectionOpts{
+			outgoing:        false,
+			remoteAddr:      nc.RemoteAddr(),
+			localPublicAddr: cl.publicAddr(remoteAddr.IP),
+			network:         nc.RemoteAddr().Network(),
+			connString:      regularNetConnPeerConnConnString(nc),
+		})
 	defer func() {
 		cl.lock()
 		defer cl.unlock()
@@ -687,13 +695,12 @@ func (cl *Client) initiateProtocolHandshakes(
 	ctx context.Context,
 	nc net.Conn,
 	t *Torrent,
-	outgoing, encryptHeader bool,
-	remoteAddr PeerRemoteAddr,
-	network, connString string,
+	encryptHeader bool,
+	newConnOpts newConnectionOpts,
 ) (
 	c *PeerConn, err error,
 ) {
-	c = cl.newConnection(nc, outgoing, remoteAddr, network, connString)
+	c = cl.newConnection(nc, newConnOpts)
 	c.headerEncrypted = encryptHeader
 	ctx, cancel := context.WithTimeout(ctx, cl.config.HandshakesTimeout)
 	defer cancel()
@@ -725,7 +732,15 @@ func (cl *Client) establishOutgoingConnEx(t *Torrent, addr PeerRemoteAddr, obfus
 		}
 		return nil, errors.New("dial failed")
 	}
-	c, err := cl.initiateProtocolHandshakes(context.Background(), nc, t, true, obfuscatedHeader, addr, dr.Dialer.DialerNetwork(), regularNetConnPeerConnConnString(nc))
+	addrIpPort, _ := tryIpPortFromNetAddr(addr)
+	c, err := cl.initiateProtocolHandshakes(context.Background(), nc, t, obfuscatedHeader, newConnectionOpts{
+		outgoing:   true,
+		remoteAddr: addr,
+		// It would be possible to retrieve a public IP from the dialer used here?
+		localPublicAddr: cl.publicAddr(addrIpPort.IP),
+		network:         dr.Dialer.DialerNetwork(),
+		connString:      regularNetConnPeerConnConnString(nc),
+	})
 	if err != nil {
 		nc.Close()
 	}
@@ -1468,28 +1483,37 @@ func (cl *Client) banPeerIP(ip net.IP) {
 	}
 }
 
-func (cl *Client) newConnection(nc net.Conn, outgoing bool, remoteAddr PeerRemoteAddr, network, connString string) (c *PeerConn) {
-	if network == "" {
-		panic(remoteAddr)
+type newConnectionOpts struct {
+	outgoing        bool
+	remoteAddr      PeerRemoteAddr
+	localPublicAddr peerLocalPublicAddr
+	network         string
+	connString      string
+}
+
+func (cl *Client) newConnection(nc net.Conn, opts newConnectionOpts) (c *PeerConn) {
+	if opts.network == "" {
+		panic(opts.remoteAddr)
 	}
 	c = &PeerConn{
 		Peer: Peer{
-			outgoing:        outgoing,
+			outgoing:        opts.outgoing,
 			choking:         true,
 			peerChoking:     true,
 			PeerMaxRequests: 250,
 
-			RemoteAddr: remoteAddr,
-			Network:    network,
-			callbacks:  &cl.config.Callbacks,
+			RemoteAddr:      opts.remoteAddr,
+			localPublicAddr: opts.localPublicAddr,
+			Network:         opts.network,
+			callbacks:       &cl.config.Callbacks,
 		},
-		connString: connString,
+		connString: opts.connString,
 		conn:       nc,
 	}
 	c.initRequestState()
 	// TODO: Need to be much more explicit about this, including allowing non-IP bannable addresses.
-	if remoteAddr != nil {
-		netipAddrPort, err := netip.ParseAddrPort(remoteAddr.String())
+	if opts.remoteAddr != nil {
+		netipAddrPort, err := netip.ParseAddrPort(opts.remoteAddr.String())
 		if err == nil {
 			c.bannableAddr = Some(netipAddrPort.Addr())
 		}
@@ -1501,7 +1525,7 @@ func (cl *Client) newConnection(nc net.Conn, outgoing bool, remoteAddr PeerRemot
 		l: cl.config.DownloadRateLimiter,
 		r: c.r,
 	}
-	c.logger.WithDefaultLevel(log.Debug).Printf("initialized with remote %v over network %v (outgoing=%t)", remoteAddr, network, outgoing)
+	c.logger.WithDefaultLevel(log.Debug).Printf("initialized with remote %v over network %v (outgoing=%t)", opts.remoteAddr, opts.network, opts.outgoing)
 	for _, f := range cl.config.Callbacks.NewPeer {
 		f(&c.Peer)
 	}

peer.go

@@ -1,5 +1,7 @@
 package torrent
 
+type peerLocalPublicAddr = IpPort
+
 func (p *Peer) isLowOnRequests() bool {
 	return p.requestState.Requests.IsEmpty() && p.requestState.Cancelled.IsEmpty()
 }

peerconn.go

@@ -64,10 +64,13 @@ type Peer struct {
 	peerImpl
 	callbacks *Callbacks
 
-	outgoing     bool
-	Network      string
-	RemoteAddr   PeerRemoteAddr
-	bannableAddr Option[bannableAddr]
+	outgoing   bool
+	Network    string
+	RemoteAddr PeerRemoteAddr
+	// The local address as observed by the remote peer. WebRTC seems to get this right without needing hints from the
+	// config.
+	localPublicAddr peerLocalPublicAddr
+	bannableAddr    Option[bannableAddr]
 	// True if the connection is operating over MSE obfuscation.
 	headerEncrypted bool
 	cryptoMethod    mse.CryptoMethod
@@ -1729,7 +1732,7 @@ func (c *PeerConn) setTorrent(t *Torrent) {
 }
 
 func (c *Peer) peerPriority() (peerPriority, error) {
-	return bep40Priority(c.remoteIpPort(), c.t.cl.publicAddr(c.remoteIp()))
+	return bep40Priority(c.remoteIpPort(), c.localPublicAddr)
 }
 
 func (c *Peer) remoteIp() net.IP {

peerconn_test.go

@@ -25,7 +25,7 @@ func TestSendBitfieldThenHave(t *testing.T) {
 	var cl Client
 	cl.init(TestingConfig(t))
 	cl.initLogger()
-	c := cl.newConnection(nil, false, nil, "io.Pipe", "")
+	c := cl.newConnection(nil, newConnectionOpts{network: "io.Pipe"})
 	c.setTorrent(cl.newTorrent(metainfo.Hash{}, nil))
 	if err := c.t.setInfo(&metainfo.Info{Pieces: make([]byte, metainfo.HashSize*3)}); err != nil {
 		t.Log(err)
@@ -107,7 +107,12 @@ func BenchmarkConnectionMainReadLoop(b *testing.B) {
 	t.onSetInfo()
 	t._pendingPieces.Add(0)
 	r, w := net.Pipe()
-	cn := cl.newConnection(r, true, r.RemoteAddr(), r.RemoteAddr().Network(), regularNetConnPeerConnConnString(r))
+	cn := cl.newConnection(r, newConnectionOpts{
+		outgoing:   true,
+		remoteAddr: r.RemoteAddr(),
+		network:    r.RemoteAddr().Network(),
+		connString: regularNetConnPeerConnConnString(r),
+	})
 	cn.setTorrent(t)
 	mrlErrChan := make(chan error)
 	msg := pp.Message{
@@ -287,7 +292,7 @@ func TestPreferredNetworkDirection(t *testing.T) {
 func TestReceiveLargeRequest(t *testing.T) {
 	c := qt.New(t)
 	cl := newTestingClient(t)
-	pc := cl.newConnection(nil, false, nil, "test", "")
+	pc := cl.newConnection(nil, newConnectionOpts{network: "test"})
 	tor := cl.newTorrentForTesting()
 	tor.info = &metainfo.Info{PieceLength: 3 << 20}
 	pc.setTorrent(tor)

pexconn_test.go

@@ -17,7 +17,10 @@ func TestPexConnState(t *testing.T) {
 	cl.initLogger()
 	torrent := cl.newTorrent(metainfo.Hash{}, nil)
 	addr := &net.TCPAddr{IP: net.IPv6loopback, Port: 4747}
-	c := cl.newConnection(nil, false, addr, addr.Network(), "")
+	c := cl.newConnection(nil, newConnectionOpts{
+		remoteAddr: addr,
+		network:    addr.Network(),
+	})
 	c.PeerExtensionIDs = make(map[pp.ExtensionName]pp.ExtensionNumber)
 	c.PeerExtensionIDs[pp.ExtensionNamePex] = pexExtendedId
 	c.messageWriter.mu.Lock()

torrent.go

@@ -1575,18 +1575,23 @@ func (t *Torrent) onWebRtcConn(
 		DataChannelContext: dcc,
 	}
 	peerRemoteAddr := netConn.RemoteAddr()
+	//t.logger.Levelf(log.Critical, "onWebRtcConn remote addr: %v", peerRemoteAddr)
 	if t.cl.badPeerAddr(peerRemoteAddr) {
 		return
 	}
+	localAddrIpPort := missinggo.IpPortFromNetAddr(netConn.LocalAddr())
 	pc, err := t.cl.initiateProtocolHandshakes(
 		context.Background(),
 		netConn,
 		t,
-		dcc.LocalOffered,
 		false,
-		netConn.RemoteAddr(),
-		webrtcNetwork,
-		fmt.Sprintf("webrtc offer_id %x: %v", dcc.OfferId, regularNetConnPeerConnConnString(netConn)),
+		newConnectionOpts{
+			outgoing:        dcc.LocalOffered,
+			remoteAddr:      peerRemoteAddr,
+			localPublicAddr: localAddrIpPort,
+			network:         webrtcNetwork,
+			connString:      fmt.Sprintf("webrtc offer_id %x: %v", dcc.OfferId, regularNetConnPeerConnConnString(netConn)),
+		},
 	)
 	if err != nil {
 		t.logger.WithDefaultLevel(log.Error).Printf("error in handshaking webrtc connection: %v", err)