Bind implementation (#779)

This PR adds supports for the WireGuard userspace implementation
using Bind interface from wireguard-go. 
The newly introduced ICEBind struct implements Bind with UDPMux-based
structs from pion/ice to handle hole punching using ICE.
The core implementation was taken from StdBind of wireguard-go.

The result is a single WireGuard port that is used for host and server reflexive candidates. 
Relay candidates are still handled separately and will be integrated in the following PRs.

ICEBind checks the incoming packets for being STUN or WireGuard ones
and routes them to UDPMux (to handle hole punching) or to WireGuard  respectively.

client/internal/proxy/direct.go

@@ -0,0 +1,57 @@
+package proxy
+
+import (
+	log "github.com/sirupsen/logrus"
+	"net"
+)
+
+// DirectNoProxy is used when there is no need for a proxy between ICE and WireGuard.
+// This is possible in either of these cases:
+// - peers are in the same local network
+// - one of the peers has a public static IP (host)
+// DirectNoProxy will just update remote peer with a remote host and fixed WireGuard port (r.g. 51820).
+// In order DirectNoProxy to work, WireGuard port has to be fixed for the time being.
+type DirectNoProxy struct {
+	config Config
+	// RemoteWgListenPort is a WireGuard port of a remote peer.
+	// It is used instead of the hardcoded 51820 port.
+	RemoteWgListenPort int
+}
+
+// NewDirectNoProxy creates a new DirectNoProxy with a provided config and remote peer's WireGuard listen port
+func NewDirectNoProxy(config Config, remoteWgPort int) *DirectNoProxy {
+	return &DirectNoProxy{config: config, RemoteWgListenPort: remoteWgPort}
+}
+
+// Close removes peer from the WireGuard interface
+func (p *DirectNoProxy) Close() error {
+	err := p.config.WgInterface.RemovePeer(p.config.RemoteKey)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// Start just updates WireGuard peer with the remote IP and default WireGuard port
+func (p *DirectNoProxy) Start(remoteConn net.Conn) error {
+
+	log.Debugf("using DirectNoProxy while connecting to peer %s", p.config.RemoteKey)
+	addr, err := net.ResolveUDPAddr("udp", remoteConn.RemoteAddr().String())
+	if err != nil {
+		return err
+	}
+	addr.Port = p.RemoteWgListenPort
+	err = p.config.WgInterface.UpdatePeer(p.config.RemoteKey, p.config.AllowedIps, DefaultWgKeepAlive,
+		addr, p.config.PreSharedKey)
+
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// Type returns the type of this proxy
+func (p *DirectNoProxy) Type() Type {
+	return TypeDirectNoProxy
+}

client/internal/proxy/noproxy.go

@@ -5,24 +5,18 @@ import (
 	"net"
 )
 
-// NoProxy is used when there is no need for a proxy between ICE and Wireguard.
-// This is possible in either of these cases:
-// - peers are in the same local network
-// - one of the peers has a public static IP (host)
-// NoProxy will just update remote peer with a remote host and fixed Wireguard port (r.g. 51820).
-// In order NoProxy to work, Wireguard port has to be fixed for the time being.
+// NoProxy is used just to configure WireGuard without any local proxy in between.
+// Used when the WireGuard interface is userspace and uses bind.ICEBind
 type NoProxy struct {
 	config Config
-	// RemoteWgListenPort is a WireGuard port of a remote peer.
-	// It is used instead of the hardcoded 51820 port.
-	RemoteWgListenPort int
 }
 
-// NewNoProxy creates a new NoProxy with a provided config and remote peer's WireGuard listen port
-func NewNoProxy(config Config, remoteWgPort int) *NoProxy {
-	return &NoProxy{config: config, RemoteWgListenPort: remoteWgPort}
+// NewNoProxy creates a new NoProxy with a provided config
+func NewNoProxy(config Config) *NoProxy {
+	return &NoProxy{config: config}
 }
 
+// Close removes peer from the WireGuard interface
 func (p *NoProxy) Close() error {
 	err := p.config.WgInterface.RemovePeer(p.config.RemoteKey)
 	if err != nil {
@@ -31,23 +25,16 @@ func (p *NoProxy) Close() error {
 	return nil
 }
 
-// Start just updates Wireguard peer with the remote IP and default Wireguard port
+// Start just updates WireGuard peer with the remote address
 func (p *NoProxy) Start(remoteConn net.Conn) error {
 
-	log.Debugf("using NoProxy while connecting to peer %s", p.config.RemoteKey)
+	log.Debugf("using NoProxy to connect to peer %s at %s", p.config.RemoteKey, remoteConn.RemoteAddr().String())
 	addr, err := net.ResolveUDPAddr("udp", remoteConn.RemoteAddr().String())
 	if err != nil {
 		return err
 	}
-	addr.Port = p.RemoteWgListenPort
-	err = p.config.WgInterface.UpdatePeer(p.config.RemoteKey, p.config.AllowedIps, DefaultWgKeepAlive,
+	return p.config.WgInterface.UpdatePeer(p.config.RemoteKey, p.config.AllowedIps, DefaultWgKeepAlive,
 		addr, p.config.PreSharedKey)
-
-	if err != nil {
-		return err
-	}
-
-	return nil
 }
 
 func (p *NoProxy) Type() Type {

client/internal/proxy/proxy.go

@@ -13,9 +13,10 @@ const DefaultWgKeepAlive = 25 * time.Second
 type Type string
 
 const (
-	TypeNoProxy   Type = "NoProxy"
-	TypeWireguard Type = "Wireguard"
-	TypeDummy     Type = "Dummy"
+	TypeDirectNoProxy Type = "DirectNoProxy"
+	TypeWireGuard     Type = "WireGuard"
+	TypeDummy         Type = "Dummy"
+	TypeNoProxy       Type = "NoProxy"
 )
 
 type Config struct {

client/internal/proxy/wireguard.go

@@ -6,8 +6,8 @@ import (
 	"net"
 )
 
-// WireguardProxy proxies
-type WireguardProxy struct {
+// WireGuardProxy proxies
+type WireGuardProxy struct {
 	ctx    context.Context
 	cancel context.CancelFunc
 
@@ -17,13 +17,13 @@ type WireguardProxy struct {
 	localConn  net.Conn
 }
 
-func NewWireguardProxy(config Config) *WireguardProxy {
-	p := &WireguardProxy{config: config}
+func NewWireGuardProxy(config Config) *WireGuardProxy {
+	p := &WireGuardProxy{config: config}
 	p.ctx, p.cancel = context.WithCancel(context.Background())
 	return p
 }
 
-func (p *WireguardProxy) updateEndpoint() error {
+func (p *WireGuardProxy) updateEndpoint() error {
 	udpAddr, err := net.ResolveUDPAddr(p.localConn.LocalAddr().Network(), p.localConn.LocalAddr().String())
 	if err != nil {
 		return err
@@ -38,7 +38,7 @@ func (p *WireguardProxy) updateEndpoint() error {
 	return nil
 }
 
-func (p *WireguardProxy) Start(remoteConn net.Conn) error {
+func (p *WireGuardProxy) Start(remoteConn net.Conn) error {
 	p.remoteConn = remoteConn
 
 	var err error
@@ -60,7 +60,7 @@ func (p *WireguardProxy) Start(remoteConn net.Conn) error {
 	return nil
 }
 
-func (p *WireguardProxy) Close() error {
+func (p *WireGuardProxy) Close() error {
 	p.cancel()
 	if c := p.localConn; c != nil {
 		err := p.localConn.Close()
@@ -77,7 +77,7 @@ func (p *WireguardProxy) Close() error {
 
 // proxyToRemote proxies everything from Wireguard to the RemoteKey peer
 // blocks
-func (p *WireguardProxy) proxyToRemote() {
+func (p *WireGuardProxy) proxyToRemote() {
 
 	buf := make([]byte, 1500)
 	for {
@@ -101,7 +101,7 @@ func (p *WireguardProxy) proxyToRemote() {
 
 // proxyToLocal proxies everything from the RemoteKey peer to local Wireguard
 // blocks
-func (p *WireguardProxy) proxyToLocal() {
+func (p *WireGuardProxy) proxyToLocal() {
 
 	buf := make([]byte, 1500)
 	for {
@@ -123,6 +123,6 @@ func (p *WireguardProxy) proxyToLocal() {
 	}
 }
 
-func (p *WireguardProxy) Type() Type {
-	return TypeWireguard
+func (p *WireGuardProxy) Type() Type {
+	return TypeWireGuard
 }