[client] Add flag to configure MTU (#4213)

client/iface/bind/ice_bind.go

@@ -56,10 +56,11 @@ type ICEBind struct {
 	muUDPMux         sync.Mutex
 	udpMux           *UniversalUDPMuxDefault
 	address          wgaddr.Address
+	mtu              uint16
 	activityRecorder *ActivityRecorder
 }
 
-func NewICEBind(transportNet transport.Net, filterFn FilterFn, address wgaddr.Address) *ICEBind {
+func NewICEBind(transportNet transport.Net, filterFn FilterFn, address wgaddr.Address, mtu uint16) *ICEBind {
 	b, _ := wgConn.NewStdNetBind().(*wgConn.StdNetBind)
 	ib := &ICEBind{
 		StdNetBind:       b,
@@ -69,6 +70,7 @@ func NewICEBind(transportNet transport.Net, filterFn FilterFn, address wgaddr.Ad
 		endpoints:        make(map[netip.Addr]net.Conn),
 		closedChan:       make(chan struct{}),
 		closed:           true,
+		mtu:              mtu,
 		address:          address,
 		activityRecorder: NewActivityRecorder(),
 	}
@@ -80,6 +82,10 @@ func NewICEBind(transportNet transport.Net, filterFn FilterFn, address wgaddr.Ad
 	return ib
 }
 
+func (s *ICEBind) MTU() uint16 {
+	return s.mtu
+}
+
 func (s *ICEBind) Open(uport uint16) ([]wgConn.ReceiveFunc, uint16, error) {
 	s.closed = false
 	s.closedChanMu.Lock()
@@ -158,6 +164,7 @@ func (s *ICEBind) createIPv4ReceiverFn(pc *ipv4.PacketConn, conn *net.UDPConn, r
 			Net:       s.transportNet,
 			FilterFn:  s.filterFn,
 			WGAddress: s.address,
+			MTU:       s.mtu,
 		},
 	)
 	return func(bufs [][]byte, sizes []int, eps []wgConn.Endpoint) (n int, err error) {

client/iface/bind/udp_mux_ios.go

@@ -4,4 +4,4 @@ package bind
 
 func (m *UDPMuxDefault) notifyAddressRemoval(addr string) {
 	// iOS doesn't support nbnet hooks, so this is a no-op
-}
+}

client/iface/bind/udp_mux_universal.go

@@ -18,6 +18,7 @@ import (
 	"github.com/pion/stun/v2"
 	"github.com/pion/transport/v3"
 
+	"github.com/netbirdio/netbird/client/iface/bufsize"
 	"github.com/netbirdio/netbird/client/iface/wgaddr"
 )
 
@@ -44,6 +45,7 @@ type UniversalUDPMuxParams struct {
 	Net                   transport.Net
 	FilterFn              FilterFn
 	WGAddress             wgaddr.Address
+	MTU                   uint16
 }
 
 // NewUniversalUDPMuxDefault creates an implementation of UniversalUDPMux embedding UDPMux
@@ -84,7 +86,7 @@ func NewUniversalUDPMuxDefault(params UniversalUDPMuxParams) *UniversalUDPMuxDef
 // just ignore other packets printing an warning message.
 // It is a blocking method, consider running in a go routine.
 func (m *UniversalUDPMuxDefault) ReadFromConn(ctx context.Context) {
-	buf := make([]byte, 1500)
+	buf := make([]byte, m.params.MTU+bufsize.WGBufferOverhead)
 	for {
 		select {
 		case <-ctx.Done():