Bind init

2026-07-20 07:21:27 +02:00 · 2023-03-27 14:57:47 +02:00
parent 71d24e59e6
commit 8ac7eaf833
5 changed files with 974 additions and 0 deletions
--- a/iface/bind/bind.go
+++ b/iface/bind/bind.go
@@ -0,0 +1,174 @@
+package bind
+
+import (
+	"errors"
+	"fmt"
+	"github.com/pion/stun"
+	log "github.com/sirupsen/logrus"
+	"golang.zx2c4.com/wireguard/conn"
+	"net"
+	"net/netip"
+	"sync"
+	"syscall"
+)
+
+type ICEBind struct {
+	sharedConn net.PacketConn
+	udpMux     *UniversalUDPMuxDefault
+
+	mu sync.Mutex // protects following fields
+}
+
+func (b *ICEBind) GetICEMux() (*UniversalUDPMuxDefault, error) {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	if b.udpMux == nil {
+		return nil, fmt.Errorf("ICEBind has not been initialized yet")
+	}
+
+	return b.udpMux, nil
+}
+
+func (b *ICEBind) Open(uport uint16) ([]conn.ReceiveFunc, uint16, error) {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	if b.sharedConn != nil {
+		return nil, 0, conn.ErrBindAlreadyOpen
+	}
+
+	port := int(uport)
+	ipv4Conn, port, err := listenNet("udp4", port)
+	if err != nil && !errors.Is(err, syscall.EAFNOSUPPORT) {
+		return nil, 0, err
+	}
+	b.sharedConn = ipv4Conn
+	b.udpMux = NewUniversalUDPMuxDefault(UniversalUDPMuxParams{UDPConn: b.sharedConn})
+
+	portAddr1, err := netip.ParseAddrPort(ipv4Conn.LocalAddr().String())
+	if err != nil {
+		return nil, 0, err
+	}
+
+	log.Infof("opened ICEBind on %s", ipv4Conn.LocalAddr().String())
+
+	return []conn.ReceiveFunc{
+			b.makeReceiveIPv4(b.sharedConn),
+		},
+		portAddr1.Port(), nil
+}
+
+func listenNet(network string, port int) (*net.UDPConn, int, error) {
+	conn, err := net.ListenUDP(network, &net.UDPAddr{Port: port})
+	if err != nil {
+		return nil, 0, err
+	}
+
+	// Retrieve port.
+	laddr := conn.LocalAddr()
+	uaddr, err := net.ResolveUDPAddr(
+		laddr.Network(),
+		laddr.String(),
+	)
+	if err != nil {
+		return nil, 0, err
+	}
+	return conn, uaddr.Port, nil
+}
+
+func parseSTUNMessage(raw []byte) (*stun.Message, error) {
+	msg := &stun.Message{
+		Raw: append([]byte{}, raw...),
+	}
+	if err := msg.Decode(); err != nil {
+		return nil, err
+	}
+
+	return msg, nil
+}
+
+func (b *ICEBind) makeReceiveIPv4(c net.PacketConn) conn.ReceiveFunc {
+	return func(buff []byte) (int, conn.Endpoint, error) {
+		n, endpoint, err := c.ReadFrom(buff)
+		if err != nil {
+			return 0, nil, err
+		}
+		e, err := netip.ParseAddrPort(endpoint.String())
+		if err != nil {
+			return 0, nil, err
+		}
+		if !stun.IsMessage(buff[:20]) {
+			// WireGuard traffic
+			return n, (*conn.StdNetEndpoint)(&net.UDPAddr{
+				IP:   e.Addr().AsSlice(),
+				Port: int(e.Port()),
+				Zone: e.Addr().Zone(),
+			}), nil
+		}
+
+		msg, err := parseSTUNMessage(buff[:n])
+		if err != nil {
+			return 0, nil, err
+		}
+
+		err = b.udpMux.HandleSTUNMessage(msg, endpoint)
+		if err != nil {
+			return 0, nil, err
+		}
+		if err != nil {
+			log.Warnf("failed to handle packet")
+		}
+
+		// discard packets because they are STUN related
+		return 0, nil, nil //todo proper return
+	}
+}
+
+func (b *ICEBind) Close() error {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	var err1, err2 error
+	if b.sharedConn != nil {
+		c := b.sharedConn
+		b.sharedConn = nil
+		err1 = c.Close()
+	}
+
+	if b.udpMux != nil {
+		m := b.udpMux
+		b.udpMux = nil
+		err2 = m.Close()
+	}
+
+	if err1 != nil {
+		return err1
+	}
+
+	return err2
+}
+
+// SetMark sets the mark for each packet sent through this Bind.
+// This mark is passed to the kernel as the socket option SO_MARK.
+func (b *ICEBind) SetMark(mark uint32) error {
+	return nil
+}
+
+func (b *ICEBind) Send(buff []byte, endpoint conn.Endpoint) error {
+	nend, ok := endpoint.(*conn.StdNetEndpoint)
+	if !ok {
+		return conn.ErrWrongEndpointType
+	}
+	_, err := b.sharedConn.WriteTo(buff, (*net.UDPAddr)(nend))
+	return err
+}
+
+// ParseEndpoint creates a new endpoint from a string.
+func (b *ICEBind) ParseEndpoint(s string) (ep conn.Endpoint, err error) {
+	e, err := netip.ParseAddrPort(s)
+	return (*conn.StdNetEndpoint)(&net.UDPAddr{
+		IP:   e.Addr().AsSlice(),
+		Port: int(e.Port()),
+		Zone: e.Addr().Zone(),
+	}), err
+}
--- a/iface/bind/udp_mux.go
+++ b/iface/bind/udp_mux.go
@@ -0,0 +1,311 @@
+package bind
+
+import (
+	"fmt"
+	"github.com/pion/stun"
+	log "github.com/sirupsen/logrus"
+	"io"
+	"net"
+	"strings"
+	"sync"
+
+	"github.com/pion/logging"
+	"github.com/pion/transport/v2"
+)
+
+const receiveMTU = 8192
+
+// UDPMuxDefault is an implementation of the interface
+type UDPMuxDefault struct {
+	params UDPMuxParams
+
+	closedChan chan struct{}
+	closeOnce  sync.Once
+
+	// connsIPv4 and connsIPv6 are maps of all udpMuxedConn indexed by ufrag|network|candidateType
+	connsIPv4, connsIPv6 map[string]*udpMuxedConn
+
+	addressMapMu sync.RWMutex
+	addressMap   map[string][]*udpMuxedConn
+
+	// buffer pool to recycle buffers for net.UDPAddr encodes/decodes
+	pool *sync.Pool
+
+	mu sync.Mutex
+
+	// for UDP connection listen at unspecified address
+	localAddrsForUnspecified []net.Addr
+}
+
+const maxAddrSize = 512
+
+// UDPMuxParams are parameters for UDPMux.
+type UDPMuxParams struct {
+	Logger  logging.LeveledLogger
+	UDPConn net.PacketConn
+
+	// Required for gathering local addresses
+	// in case a un UDPConn is passed which does not
+	// bind to a specific local address.
+	Net transport.Net
+}
+
+// NewUDPMuxDefault creates an implementation of UDPMux
+func NewUDPMuxDefault(params UDPMuxParams) *UDPMuxDefault {
+	if params.Logger == nil {
+		params.Logger = logging.NewDefaultLoggerFactory().NewLogger("ice")
+	}
+
+	return &UDPMuxDefault{
+		addressMap: map[string][]*udpMuxedConn{},
+		params:     params,
+		connsIPv4:  make(map[string]*udpMuxedConn),
+		connsIPv6:  make(map[string]*udpMuxedConn),
+		closedChan: make(chan struct{}, 1),
+		pool: &sync.Pool{
+			New: func() interface{} {
+				// big enough buffer to fit both packet and address
+				return newBufferHolder(receiveMTU + maxAddrSize)
+			},
+		},
+		localAddrsForUnspecified: []net.Addr{},
+	}
+}
+
+// LocalAddr returns the listening address of this UDPMuxDefault
+func (m *UDPMuxDefault) LocalAddr() net.Addr {
+	return m.params.UDPConn.LocalAddr()
+}
+
+// GetListenAddresses returns the list of addresses that this mux is listening on
+func (m *UDPMuxDefault) GetListenAddresses() []net.Addr {
+	if len(m.localAddrsForUnspecified) > 0 {
+		return m.localAddrsForUnspecified
+	}
+
+	return []net.Addr{m.LocalAddr()}
+}
+
+// GetConn returns a PacketConn given the connection's ufrag and network address
+// creates the connection if an existing one can't be found
+func (m *UDPMuxDefault) GetConn(ufrag string, addr net.Addr) (net.PacketConn, error) {
+
+	var isIPv6 bool
+	if udpAddr, _ := addr.(*net.UDPAddr); udpAddr != nil && udpAddr.IP.To4() == nil {
+		isIPv6 = true
+	}
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	if m.IsClosed() {
+		return nil, io.ErrClosedPipe
+	}
+
+	if conn, ok := m.getConn(ufrag, isIPv6); ok {
+		return conn, nil
+	}
+
+	c := m.createMuxedConn(ufrag)
+	go func() {
+		<-c.CloseChannel()
+		m.RemoveConnByUfrag(ufrag)
+	}()
+
+	if isIPv6 {
+		m.connsIPv6[ufrag] = c
+	} else {
+		m.connsIPv4[ufrag] = c
+	}
+
+	return c, nil
+}
+
+// RemoveConnByUfrag stops and removes the muxed packet connection
+func (m *UDPMuxDefault) RemoveConnByUfrag(ufrag string) {
+	removedConns := make([]*udpMuxedConn, 0, 2)
+
+	// Keep lock section small to avoid deadlock with conn lock
+	m.mu.Lock()
+	if c, ok := m.connsIPv4[ufrag]; ok {
+		delete(m.connsIPv4, ufrag)
+		removedConns = append(removedConns, c)
+	}
+	if c, ok := m.connsIPv6[ufrag]; ok {
+		delete(m.connsIPv6, ufrag)
+		removedConns = append(removedConns, c)
+	}
+	m.mu.Unlock()
+
+	if len(removedConns) == 0 {
+		// No need to lock if no connection was found
+		return
+	}
+
+	m.addressMapMu.Lock()
+	defer m.addressMapMu.Unlock()
+
+	for _, c := range removedConns {
+		addresses := c.getAddresses()
+		for _, addr := range addresses {
+			if connList, ok := m.addressMap[addr]; ok {
+				var newList []*udpMuxedConn
+				for _, conn := range connList {
+					if conn.params.Key != ufrag {
+						newList = append(newList, conn)
+					}
+				}
+				m.addressMap[addr] = newList
+			}
+		}
+	}
+}
+
+// IsClosed returns true if the mux had been closed
+func (m *UDPMuxDefault) IsClosed() bool {
+	select {
+	case <-m.closedChan:
+		return true
+	default:
+		return false
+	}
+}
+
+// Close the mux, no further connections could be created
+func (m *UDPMuxDefault) Close() error {
+	var err error
+	m.closeOnce.Do(func() {
+		m.mu.Lock()
+		defer m.mu.Unlock()
+
+		for _, c := range m.connsIPv4 {
+			_ = c.Close()
+		}
+		for _, c := range m.connsIPv6 {
+			_ = c.Close()
+		}
+
+		m.connsIPv4 = make(map[string]*udpMuxedConn)
+		m.connsIPv6 = make(map[string]*udpMuxedConn)
+
+		close(m.closedChan)
+
+		_ = m.params.UDPConn.Close()
+	})
+	return err
+}
+
+func (m *UDPMuxDefault) writeTo(buf []byte, rAddr net.Addr) (n int, err error) {
+	return m.params.UDPConn.WriteTo(buf, rAddr)
+}
+
+func (m *UDPMuxDefault) registerConnForAddress(conn *udpMuxedConn, addr string) {
+	if m.IsClosed() {
+		return
+	}
+
+	m.addressMapMu.Lock()
+	defer m.addressMapMu.Unlock()
+
+	existing, ok := m.addressMap[addr]
+	if !ok {
+		existing = []*udpMuxedConn{}
+	}
+	existing = append(existing, conn)
+	m.addressMap[addr] = existing
+
+	log.Debugf("ICE: registered %s for %s", addr, conn.params.Key)
+}
+
+func (m *UDPMuxDefault) createMuxedConn(key string) *udpMuxedConn {
+	c := newUDPMuxedConn(&udpMuxedConnParams{
+		Mux:       m,
+		Key:       key,
+		AddrPool:  m.pool,
+		LocalAddr: m.LocalAddr(),
+		Logger:    m.params.Logger,
+	})
+	return c
+}
+
+func (m *UDPMuxDefault) HandleSTUNMessage(msg *stun.Message, addr net.Addr) error {
+
+	remoteAddr, ok := addr.(*net.UDPAddr)
+	if !ok {
+		return fmt.Errorf("underlying PacketConn did not return a UDPAddr")
+	}
+
+	// If we have already seen this address dispatch to the appropriate destination
+	// If you are using the same socket for the Host and SRFLX candidates, it might be that there are more than one
+	// muxed connection - one for the SRFLX candidate and the other one for the HOST one.
+	// We will then forward STUN packets to each of these connections.
+	m.addressMapMu.Lock()
+	var destinationConnList []*udpMuxedConn
+	if storedConns, ok := m.addressMap[addr.String()]; ok {
+		for _, conn := range storedConns {
+			destinationConnList = append(destinationConnList, conn)
+		}
+	}
+	m.addressMapMu.Unlock()
+
+	var isIPv6 bool
+	if udpAddr, _ := addr.(*net.UDPAddr); udpAddr != nil && udpAddr.IP.To4() == nil {
+		isIPv6 = true
+	}
+
+	// This block is needed to discover Peer Reflexive Candidates for which we don't know the Endpoint upfront.
+	// However, we can take a username attribute from the STUN message which contains ufrag.
+	// We can use ufrag to identify the destination conn to route packet to.
+	attr, stunAttrErr := msg.Get(stun.AttrUsername)
+	if stunAttrErr == nil {
+		ufrag := strings.Split(string(attr), ":")[0]
+
+		m.mu.Lock()
+		destinationConn := m.connsIPv4[ufrag]
+		if isIPv6 {
+			destinationConn = m.connsIPv6[ufrag]
+		}
+
+		if destinationConn != nil {
+			exists := false
+			for _, conn := range destinationConnList {
+				if conn.params.Key == destinationConn.params.Key {
+					exists = true
+					break
+				}
+			}
+			if !exists {
+				destinationConnList = append(destinationConnList, destinationConn)
+			}
+		}
+		m.mu.Unlock()
+	}
+
+	// Forward STUN packets to each destination connections even thought the STUN packet might not belong there.
+	// It will be discarded by the further ICE candidate logic if so.
+	for _, conn := range destinationConnList {
+		if err := conn.writePacket(msg.Raw, remoteAddr); err != nil {
+			log.Errorf("could not write packet: %v", err)
+		}
+	}
+
+	return nil
+}
+
+func (m *UDPMuxDefault) getConn(ufrag string, isIPv6 bool) (val *udpMuxedConn, ok bool) {
+	if isIPv6 {
+		val, ok = m.connsIPv6[ufrag]
+	} else {
+		val, ok = m.connsIPv4[ufrag]
+	}
+	return
+}
+
+type bufferHolder struct {
+	buf []byte
+}
+
+func newBufferHolder(size int) *bufferHolder {
+	return &bufferHolder{
+		buf: make([]byte, size),
+	}
+}
--- a/iface/bind/udp_mux_universal.go
+++ b/iface/bind/udp_mux_universal.go
@@ -0,0 +1,244 @@
+package bind
+
+import (
+	"fmt"
+	log "github.com/sirupsen/logrus"
+	"net"
+	"time"
+
+	"github.com/pion/logging"
+	"github.com/pion/stun"
+	"github.com/pion/transport/v2"
+)
+
+// UniversalUDPMuxDefault handles STUN and TURN servers packets by wrapping the original UDPConn
+// It then passes packets to the UDPMux that does the actual connection muxing.
+type UniversalUDPMuxDefault struct {
+	*UDPMuxDefault
+	params UniversalUDPMuxParams
+
+	// since we have a shared socket, for srflx candidates it makes sense to have a shared mapped address across all the agents
+	// stun.XORMappedAddress indexed by the STUN server addr
+	xorMappedMap map[string]*xorMapped
+}
+
+// UniversalUDPMuxParams are parameters for UniversalUDPMux server reflexive.
+type UniversalUDPMuxParams struct {
+	Logger                logging.LeveledLogger
+	UDPConn               net.PacketConn
+	XORMappedAddrCacheTTL time.Duration
+	Net                   transport.Net
+}
+
+// NewUniversalUDPMuxDefault creates an implementation of UniversalUDPMux embedding UDPMux
+func NewUniversalUDPMuxDefault(params UniversalUDPMuxParams) *UniversalUDPMuxDefault {
+	if params.Logger == nil {
+		params.Logger = logging.NewDefaultLoggerFactory().NewLogger("ice")
+	}
+	if params.XORMappedAddrCacheTTL == 0 {
+		params.XORMappedAddrCacheTTL = time.Second * 25
+	}
+
+	m := &UniversalUDPMuxDefault{
+		params:       params,
+		xorMappedMap: make(map[string]*xorMapped),
+	}
+
+	// wrap UDP connection, process server reflexive messages
+	// before they are passed to the UDPMux connection handler (connWorker)
+	m.params.UDPConn = &udpConn{
+		PacketConn: params.UDPConn,
+		mux:        m,
+		logger:     params.Logger,
+	}
+
+	// embed UDPMux
+	udpMuxParams := UDPMuxParams{
+		Logger:  params.Logger,
+		UDPConn: m.params.UDPConn,
+		Net:     m.params.Net,
+	}
+	m.UDPMuxDefault = NewUDPMuxDefault(udpMuxParams)
+
+	return m
+}
+
+// udpConn is a wrapper around UDPMux conn that overrides ReadFrom and handles STUN/TURN packets
+type udpConn struct {
+	net.PacketConn
+	mux    *UniversalUDPMuxDefault
+	logger logging.LeveledLogger
+}
+
+// GetRelayedAddr creates relayed connection to the given TURN service and returns the relayed addr.
+// Not implemented yet.
+func (m *UniversalUDPMuxDefault) GetRelayedAddr(turnAddr net.Addr, deadline time.Duration) (*net.Addr, error) {
+	return nil, fmt.Errorf("not implemented yet")
+}
+
+// GetConnForURL add uniques to the muxed connection by concatenating ufrag and URL (e.g. STUN URL) to be able to support multiple STUN/TURN servers
+// and return a unique connection per server.
+func (m *UniversalUDPMuxDefault) GetConnForURL(ufrag string, url string, addr net.Addr) (net.PacketConn, error) {
+	return m.UDPMuxDefault.GetConn(fmt.Sprintf("%s%s", ufrag, url), addr)
+}
+
+// HandleSTUNMessage discovers STUN packets that carry a XOR mapped address from a STUN server.
+// All other STUN packets will be forwarded to the UDPMux
+func (m *UniversalUDPMuxDefault) HandleSTUNMessage(msg *stun.Message, addr net.Addr) error {
+
+	udpAddr, ok := addr.(*net.UDPAddr)
+	if !ok {
+		// message about this err will be logged in the UDPMux
+		return nil
+	}
+
+	if m.isXORMappedResponse(msg, udpAddr.String()) {
+		err := m.handleXORMappedResponse(udpAddr, msg)
+		if err != nil {
+			log.Debugf("%s: %v", fmt.Errorf("failed to get XOR-MAPPED-ADDRESS response"), err)
+			return nil
+		}
+		return nil
+	}
+	return m.UDPMuxDefault.HandleSTUNMessage(msg, addr)
+}
+
+// isXORMappedResponse indicates whether the message is a XORMappedAddress and is coming from the known STUN server.
+func (m *UniversalUDPMuxDefault) isXORMappedResponse(msg *stun.Message, stunAddr string) bool {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	// check first if it is a STUN server address because remote peer can also send similar messages but as a BindingSuccess
+	_, ok := m.xorMappedMap[stunAddr]
+	_, err := msg.Get(stun.AttrXORMappedAddress)
+	return err == nil && ok
+}
+
+// handleXORMappedResponse parses response from the STUN server, extracts XORMappedAddress attribute
+// and set the mapped address for the server
+func (m *UniversalUDPMuxDefault) handleXORMappedResponse(stunAddr *net.UDPAddr, msg *stun.Message) error {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	mappedAddr, ok := m.xorMappedMap[stunAddr.String()]
+	if !ok {
+		return fmt.Errorf("no XOR address mapping")
+	}
+
+	var addr stun.XORMappedAddress
+	if err := addr.GetFrom(msg); err != nil {
+		return err
+	}
+
+	m.xorMappedMap[stunAddr.String()] = mappedAddr
+	mappedAddr.SetAddr(&addr)
+
+	return nil
+}
+
+// GetXORMappedAddr returns *stun.XORMappedAddress if already present for a given STUN server.
+// Makes a STUN binding request to discover mapped address otherwise.
+// Blocks until the stun.XORMappedAddress has been discovered or deadline.
+// Method is safe for concurrent use.
+func (m *UniversalUDPMuxDefault) GetXORMappedAddr(serverAddr net.Addr, deadline time.Duration) (*stun.XORMappedAddress, error) {
+	m.mu.Lock()
+	mappedAddr, ok := m.xorMappedMap[serverAddr.String()]
+	// if we already have a mapping for this STUN server (address already received)
+	// and if it is not too old we return it without making a new request to STUN server
+	if ok {
+		if mappedAddr.expired() {
+			mappedAddr.closeWaiters()
+			delete(m.xorMappedMap, serverAddr.String())
+			ok = false
+		} else if mappedAddr.pending() {
+			ok = false
+		}
+	}
+	m.mu.Unlock()
+	if ok {
+		return mappedAddr.addr, nil
+	}
+
+	// otherwise, make a STUN request to discover the address
+	// or wait for already sent request to complete
+	waitAddrReceived, err := m.sendStun(serverAddr)
+	if err != nil {
+		return nil, fmt.Errorf("%s: %s", "failed to send STUN packet", err)
+	}
+
+	// block until response was handled by the connWorker routine and XORMappedAddress was updated
+	select {
+	case <-waitAddrReceived:
+		// when channel closed, addr was obtained
+		m.mu.Lock()
+		mappedAddr := *m.xorMappedMap[serverAddr.String()]
+		m.mu.Unlock()
+		if mappedAddr.addr == nil {
+			return nil, fmt.Errorf("no XOR address mapping")
+		}
+		return mappedAddr.addr, nil
+	case <-time.After(deadline):
+		return nil, fmt.Errorf("timeout while waiting for XORMappedAddr")
+	}
+}
+
+// sendStun sends a STUN request via UDP conn.
+//
+// The returned channel is closed when the STUN response has been received.
+// Method is safe for concurrent use.
+func (m *UniversalUDPMuxDefault) sendStun(serverAddr net.Addr) (chan struct{}, error) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	// if record present in the map, we already sent a STUN request,
+	// just wait when waitAddrReceived will be closed
+	addrMap, ok := m.xorMappedMap[serverAddr.String()]
+	if !ok {
+		addrMap = &xorMapped{
+			expiresAt:        time.Now().Add(m.params.XORMappedAddrCacheTTL),
+			waitAddrReceived: make(chan struct{}),
+		}
+		m.xorMappedMap[serverAddr.String()] = addrMap
+	}
+
+	req, err := stun.Build(stun.BindingRequest, stun.TransactionID)
+	if err != nil {
+		return nil, err
+	}
+
+	if _, err = m.params.UDPConn.WriteTo(req.Raw, serverAddr); err != nil {
+		return nil, err
+	}
+
+	return addrMap.waitAddrReceived, nil
+}
+
+type xorMapped struct {
+	addr             *stun.XORMappedAddress
+	waitAddrReceived chan struct{}
+	expiresAt        time.Time
+}
+
+func (a *xorMapped) closeWaiters() {
+	select {
+	case <-a.waitAddrReceived:
+		// notify was close, ok, that means we received duplicate response
+		// just exit
+		break
+	default:
+		// notify tha twe have a new addr
+		close(a.waitAddrReceived)
+	}
+}
+
+func (a *xorMapped) pending() bool {
+	return a.addr == nil
+}
+
+func (a *xorMapped) expired() bool {
+	return a.expiresAt.Before(time.Now())
+}
+
+func (a *xorMapped) SetAddr(addr *stun.XORMappedAddress) {
+	a.addr = addr
+	a.closeWaiters()
+}
--- a/iface/bind/udp_muxed_conn.go
+++ b/iface/bind/udp_muxed_conn.go
@@ -0,0 +1,243 @@
+package bind
+
+import (
+	"encoding/binary"
+	"io"
+	"net"
+	"sync"
+	"time"
+
+	"github.com/pion/logging"
+	"github.com/pion/transport/v2/packetio"
+)
+
+type udpMuxedConnParams struct {
+	Mux       *UDPMuxDefault
+	AddrPool  *sync.Pool
+	Key       string
+	LocalAddr net.Addr
+	Logger    logging.LeveledLogger
+}
+
+// udpMuxedConn represents a logical packet conn for a single remote as identified by ufrag
+type udpMuxedConn struct {
+	params *udpMuxedConnParams
+	// remote addresses that we have sent to on this conn
+	addresses []string
+
+	// channel holding incoming packets
+	buf        *packetio.Buffer
+	closedChan chan struct{}
+	closeOnce  sync.Once
+	mu         sync.Mutex
+}
+
+func newUDPMuxedConn(params *udpMuxedConnParams) *udpMuxedConn {
+	p := &udpMuxedConn{
+		params:     params,
+		buf:        packetio.NewBuffer(),
+		closedChan: make(chan struct{}),
+	}
+
+	return p
+}
+
+func (c *udpMuxedConn) ReadFrom(b []byte) (n int, rAddr net.Addr, err error) {
+	buf := c.params.AddrPool.Get().(*bufferHolder) //nolint:forcetypeassert
+	defer c.params.AddrPool.Put(buf)
+
+	// read address
+	total, err := c.buf.Read(buf.buf)
+	if err != nil {
+		return 0, nil, err
+	}
+
+	dataLen := int(binary.LittleEndian.Uint16(buf.buf[:2]))
+	if dataLen > total || dataLen > len(b) {
+		return 0, nil, io.ErrShortBuffer
+	}
+
+	// read data and then address
+	offset := 2
+	copy(b, buf.buf[offset:offset+dataLen])
+	offset += dataLen
+
+	// read address len & decode address
+	addrLen := int(binary.LittleEndian.Uint16(buf.buf[offset : offset+2]))
+	offset += 2
+
+	if rAddr, err = decodeUDPAddr(buf.buf[offset : offset+addrLen]); err != nil {
+		return 0, nil, err
+	}
+
+	return dataLen, rAddr, nil
+}
+
+func (c *udpMuxedConn) WriteTo(buf []byte, rAddr net.Addr) (n int, err error) {
+	if c.isClosed() {
+		return 0, io.ErrClosedPipe
+	}
+	// each time we write to a new address, we'll register it with the mux
+	addr := rAddr.String()
+	if !c.containsAddress(addr) {
+		c.addAddress(addr)
+	}
+
+	return c.params.Mux.writeTo(buf, rAddr)
+}
+
+func (c *udpMuxedConn) LocalAddr() net.Addr {
+	return c.params.LocalAddr
+}
+
+func (c *udpMuxedConn) SetDeadline(tm time.Time) error {
+	return nil
+}
+
+func (c *udpMuxedConn) SetReadDeadline(tm time.Time) error {
+	return nil
+}
+
+func (c *udpMuxedConn) SetWriteDeadline(tm time.Time) error {
+	return nil
+}
+
+func (c *udpMuxedConn) CloseChannel() <-chan struct{} {
+	return c.closedChan
+}
+
+func (c *udpMuxedConn) Close() error {
+	var err error
+	c.closeOnce.Do(func() {
+		err = c.buf.Close()
+		close(c.closedChan)
+	})
+	return err
+}
+
+func (c *udpMuxedConn) isClosed() bool {
+	select {
+	case <-c.closedChan:
+		return true
+	default:
+		return false
+	}
+}
+
+func (c *udpMuxedConn) getAddresses() []string {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	addresses := make([]string, len(c.addresses))
+	copy(addresses, c.addresses)
+	return addresses
+}
+
+func (c *udpMuxedConn) addAddress(addr string) {
+	c.mu.Lock()
+	c.addresses = append(c.addresses, addr)
+	c.mu.Unlock()
+
+	// map it on mux
+	c.params.Mux.registerConnForAddress(c, addr)
+}
+
+func (c *udpMuxedConn) removeAddress(addr string) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	newAddresses := make([]string, 0, len(c.addresses))
+	for _, a := range c.addresses {
+		if a != addr {
+			newAddresses = append(newAddresses, a)
+		}
+	}
+
+	c.addresses = newAddresses
+}
+
+func (c *udpMuxedConn) containsAddress(addr string) bool {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	for _, a := range c.addresses {
+		if addr == a {
+			return true
+		}
+	}
+	return false
+}
+
+func (c *udpMuxedConn) writePacket(data []byte, addr *net.UDPAddr) error {
+	// write two packets, address and data
+	buf := c.params.AddrPool.Get().(*bufferHolder) //nolint:forcetypeassert
+	defer c.params.AddrPool.Put(buf)
+
+	// format of buffer | data len | data bytes | addr len | addr bytes |
+	if len(buf.buf) < len(data)+maxAddrSize {
+		return io.ErrShortBuffer
+	}
+	// data len
+	binary.LittleEndian.PutUint16(buf.buf, uint16(len(data)))
+	offset := 2
+
+	// data
+	copy(buf.buf[offset:], data)
+	offset += len(data)
+
+	// write address first, leaving room for its length
+	n, err := encodeUDPAddr(addr, buf.buf[offset+2:])
+	if err != nil {
+		return err
+	}
+	total := offset + n + 2
+
+	// address len
+	binary.LittleEndian.PutUint16(buf.buf[offset:], uint16(n))
+
+	if _, err := c.buf.Write(buf.buf[:total]); err != nil {
+		return err
+	}
+	return nil
+}
+
+func encodeUDPAddr(addr *net.UDPAddr, buf []byte) (int, error) {
+	ipData, err := addr.IP.MarshalText()
+	if err != nil {
+		return 0, err
+	}
+	total := 2 + len(ipData) + 2 + len(addr.Zone)
+	if total > len(buf) {
+		return 0, io.ErrShortBuffer
+	}
+
+	binary.LittleEndian.PutUint16(buf, uint16(len(ipData)))
+	offset := 2
+	n := copy(buf[offset:], ipData)
+	offset += n
+	binary.LittleEndian.PutUint16(buf[offset:], uint16(addr.Port))
+	offset += 2
+	copy(buf[offset:], addr.Zone)
+	return total, nil
+}
+
+func decodeUDPAddr(buf []byte) (*net.UDPAddr, error) {
+	addr := net.UDPAddr{}
+
+	offset := 0
+	ipLen := int(binary.LittleEndian.Uint16(buf[:2]))
+	offset += 2
+	// basic bounds checking
+	if ipLen+offset > len(buf) {
+		return nil, io.ErrShortBuffer
+	}
+	if err := addr.IP.UnmarshalText(buf[offset : offset+ipLen]); err != nil {
+		return nil, err
+	}
+	offset += ipLen
+	addr.Port = int(binary.LittleEndian.Uint16(buf[offset : offset+2]))
+	offset += 2
+	zone := make([]byte, len(buf[offset:]))
+	copy(zone, buf[offset:])
+	addr.Zone = string(zone)
+
+	return &addr, nil
+}
--- a/iface/tun_unix.go
+++ b/iface/tun_unix.go
@@ -3,6 +3,7 @@
 package iface

 import (
+	"github.com/netbirdio/netbird/iface/bind"
 	"net"
 	"os"

@@ -18,6 +19,7 @@ type tunDevice struct {
 	address      WGAddress
 	mtu          int
 	netInterface NetInterface
+	iceBind      *bind.ICEBind
 }

 func newTunDevice(name string, address WGAddress, mtu int) *tunDevice {