[client] Fix TURN-Relay switch (#3456)

- When a peer is connected with TURN and a Relay connection is established, do not force switching to Relay. Keep using TURN until disconnection.

-In the proxy preparation phase, the Bind Proxy does not set the remote conn as a fake address for Bind. When running the Work() function, the proper proxy instance updates the conn inside the Bind.

client/iface/bind/ice_bind.go

@@ -5,7 +5,6 @@ import (
 	"net"
 	"net/netip"
 	"runtime"
-	"strings"
 	"sync"
 
 	"github.com/pion/stun/v2"
@@ -108,35 +107,17 @@ func (s *ICEBind) GetICEMux() (*UniversalUDPMuxDefault, error) {
 	return s.udpMux, nil
 }
 
-func (b *ICEBind) SetEndpoint(peerAddress *net.UDPAddr, conn net.Conn) (*net.UDPAddr, error) {
+func (b *ICEBind) SetEndpoint(fakeIP netip.Addr, conn net.Conn) {
-	fakeUDPAddr, err := fakeAddress(peerAddress)
-	if err != nil {
-		return nil, err
-	}
-
-	// force IPv4
-	fakeAddr, ok := netip.AddrFromSlice(fakeUDPAddr.IP.To4())
-	if !ok {
-		return nil, fmt.Errorf("failed to convert IP to netip.Addr")
-	}
-
 	b.endpointsMu.Lock()
-	b.endpoints[fakeAddr] = conn
+	b.endpoints[fakeIP] = conn
 	b.endpointsMu.Unlock()
-
-	return fakeUDPAddr, nil
 }
 
-func (b *ICEBind) RemoveEndpoint(fakeUDPAddr *net.UDPAddr) {
+func (b *ICEBind) RemoveEndpoint(fakeIP netip.Addr) {
-	fakeAddr, ok := netip.AddrFromSlice(fakeUDPAddr.IP.To4())
-	if !ok {
-		log.Warnf("failed to convert IP to netip.Addr")
-		return
-	}
-
 	b.endpointsMu.Lock()
 	defer b.endpointsMu.Unlock()
-	delete(b.endpoints, fakeAddr)
+
+	delete(b.endpoints, fakeIP)
 }
 
 func (b *ICEBind) Send(bufs [][]byte, ep wgConn.Endpoint) error {
@@ -275,21 +256,6 @@ func (c *ICEBind) receiveRelayed(buffs [][]byte, sizes []int, eps []wgConn.Endpo
 	}
 }
 
-// fakeAddress returns a fake address that is used to as an identifier for the peer.
-// The fake address is in the format of 127.1.x.x where x.x is the last two octets of the peer address.
-func fakeAddress(peerAddress *net.UDPAddr) (*net.UDPAddr, error) {
-	octets := strings.Split(peerAddress.IP.String(), ".")
-	if len(octets) != 4 {
-		return nil, fmt.Errorf("invalid IP format")
-	}
-
-	newAddr := &net.UDPAddr{
-		IP:   net.ParseIP(fmt.Sprintf("127.1.%s.%s", octets[2], octets[3])),
-		Port: peerAddress.Port,
-	}
-	return newAddr, nil
-}
-
 func getMessages(msgsPool *sync.Pool) *[]ipv6.Message {
 	return msgsPool.Get().(*[]ipv6.Message)
 }

client/iface/wgproxy/bind/proxy.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"net"
 	"net/netip"
+	"strings"
 	"sync"
 
 	log "github.com/sirupsen/logrus"
@@ -16,8 +17,8 @@ import (
 type ProxyBind struct {
 	Bind *bind.ICEBind
 
-	wgAddr     *net.UDPAddr
+	fakeNetIP      *netip.AddrPort
-	wgEndpoint *bind.Endpoint
+	wgBindEndpoint *bind.Endpoint
 	remoteConn     net.Conn
 	ctx            context.Context
 	cancel         context.CancelFunc
@@ -33,20 +34,24 @@ type ProxyBind struct {
 // endpoint is the NetBird address of the remote peer. The SetEndpoint return with the address what will be used in the
 // WireGuard configuration.
 func (p *ProxyBind) AddTurnConn(ctx context.Context, nbAddr *net.UDPAddr, remoteConn net.Conn) error {
-	addr, err := p.Bind.SetEndpoint(nbAddr, remoteConn)
+	fakeNetIP, err := fakeAddress(nbAddr)
 	if err != nil {
 		return err
 	}
 
-	p.wgAddr = addr
+	p.fakeNetIP = fakeNetIP
-	p.wgEndpoint = addrToEndpoint(addr)
+	p.wgBindEndpoint = &bind.Endpoint{AddrPort: *fakeNetIP}
 	p.remoteConn = remoteConn
 	p.ctx, p.cancel = context.WithCancel(ctx)
-	return err
+	return nil
 
 }
 func (p *ProxyBind) EndpointAddr() *net.UDPAddr {
-	return p.wgAddr
+	return &net.UDPAddr{
+		IP:   p.fakeNetIP.Addr().AsSlice(),
+		Port: int(p.fakeNetIP.Port()),
+		Zone: p.fakeNetIP.Addr().Zone(),
+	}
 }
 
 func (p *ProxyBind) Work() {
@@ -54,6 +59,8 @@ func (p *ProxyBind) Work() {
 		return
 	}
 
+	p.Bind.SetEndpoint(p.fakeNetIP.Addr(), p.remoteConn)
+
 	p.pausedMu.Lock()
 	p.paused = false
 	p.pausedMu.Unlock()
@@ -93,7 +100,7 @@ func (p *ProxyBind) close() error {
 
 	p.cancel()
 
-	p.Bind.RemoveEndpoint(p.wgAddr)
+	p.Bind.RemoveEndpoint(p.fakeNetIP.Addr())
 
 	if rErr := p.remoteConn.Close(); rErr != nil && !errors.Is(rErr, net.ErrClosed) {
 		return rErr
@@ -126,7 +133,7 @@ func (p *ProxyBind) proxyToLocal(ctx context.Context) {
 		}
 
 		msg := bind.RecvMessage{
-			Endpoint: p.wgEndpoint,
+			Endpoint: p.wgBindEndpoint,
 			Buffer:   buf[:n],
 		}
 		p.Bind.RecvChan <- msg
@@ -134,8 +141,19 @@ func (p *ProxyBind) proxyToLocal(ctx context.Context) {
 	}
 }
 
-func addrToEndpoint(addr *net.UDPAddr) *bind.Endpoint {
+// fakeAddress returns a fake address that is used to as an identifier for the peer.
-	ip, _ := netip.AddrFromSlice(addr.IP.To4())
+// The fake address is in the format of 127.1.x.x where x.x is the last two octets of the peer address.
-	addrPort := netip.AddrPortFrom(ip, uint16(addr.Port))
+func fakeAddress(peerAddress *net.UDPAddr) (*netip.AddrPort, error) {
-	return &bind.Endpoint{AddrPort: addrPort}
+	octets := strings.Split(peerAddress.IP.String(), ".")
+	if len(octets) != 4 {
+		return nil, fmt.Errorf("invalid IP format")
+	}
+
+	fakeIP, err := netip.ParseAddr(fmt.Sprintf("127.1.%s.%s", octets[2], octets[3]))
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse new IP: %w", err)
+	}
+
+	netipAddr := netip.AddrPortFrom(fakeIP, uint16(peerAddress.Port))
+	return &netipAddr, nil
 }

client/internal/peer/conn.go

@@ -442,8 +442,8 @@ func (conn *Conn) onRelayConnectionIsReady(rci RelayConnInfo) {
 
 	conn.log.Infof("created new wgProxy for relay connection: %s", wgProxy.EndpointAddr().String())
 
-	if conn.iceP2PIsActive() {
+	if conn.isICEActive() {
-		conn.log.Debugf("do not switch to relay because current priority is: %s", conn.currentConnPriority.String())
+		conn.log.Infof("do not switch to relay because current priority is: %s", conn.currentConnPriority.String())
 		conn.setRelayedProxy(wgProxy)
 		conn.statusRelay.Set(StatusConnected)
 		conn.updateRelayStatus(rci.relayedConn.RemoteAddr().String(), rci.rosenpassPubKey)
@@ -711,8 +711,8 @@ func (conn *Conn) isReadyToUpgrade() bool {
 	return conn.wgProxyRelay != nil && conn.currentConnPriority != connPriorityRelay
 }
 
-func (conn *Conn) iceP2PIsActive() bool {
+func (conn *Conn) isICEActive() bool {
-	return conn.currentConnPriority == connPriorityICEP2P && conn.statusICE.Get() == StatusConnected
+	return (conn.currentConnPriority == connPriorityICEP2P || conn.currentConnPriority == connPriorityICETurn) && conn.statusICE.Get() == StatusConnected
 }
 
 func (conn *Conn) removeWgPeer() error {