[client] Eliminate UDP proxy in user-space mode (#2712)

In the case of user space WireGuard mode, use in-memory proxy between the TURN/Relay connection and the WireGuard Bind. We keep the UDP proxy and eBPF proxy for kernel mode.

The key change is the new wgproxy/bind and the iface/bind/ice_bind changes. Everything else is just to fulfill the dependencies.

client/iface/wgproxy/proxy_test.go

@@ -0,0 +1,128 @@
+//go:build linux
+
+package wgproxy
+
+import (
+	"context"
+	"io"
+	"net"
+	"os"
+	"runtime"
+	"testing"
+	"time"
+
+	"github.com/netbirdio/netbird/client/iface/wgproxy/ebpf"
+	udpProxy "github.com/netbirdio/netbird/client/iface/wgproxy/udp"
+	"github.com/netbirdio/netbird/util"
+)
+
+func TestMain(m *testing.M) {
+	_ = util.InitLog("trace", "console")
+	code := m.Run()
+	os.Exit(code)
+}
+
+type mocConn struct {
+	closeChan chan struct{}
+	closed    bool
+}
+
+func newMockConn() *mocConn {
+	return &mocConn{
+		closeChan: make(chan struct{}),
+	}
+}
+
+func (m *mocConn) Read(b []byte) (n int, err error) {
+	<-m.closeChan
+	return 0, io.EOF
+}
+
+func (m *mocConn) Write(b []byte) (n int, err error) {
+	<-m.closeChan
+	return 0, io.EOF
+}
+
+func (m *mocConn) Close() error {
+	if m.closed == true {
+		return nil
+	}
+
+	m.closed = true
+	close(m.closeChan)
+	return nil
+}
+
+func (m *mocConn) LocalAddr() net.Addr {
+	panic("implement me")
+}
+
+func (m *mocConn) RemoteAddr() net.Addr {
+	return &net.UDPAddr{
+		IP: net.ParseIP("172.16.254.1"),
+	}
+}
+
+func (m *mocConn) SetDeadline(t time.Time) error {
+	panic("implement me")
+}
+
+func (m *mocConn) SetReadDeadline(t time.Time) error {
+	panic("implement me")
+}
+
+func (m *mocConn) SetWriteDeadline(t time.Time) error {
+	panic("implement me")
+}
+
+func TestProxyCloseByRemoteConn(t *testing.T) {
+	ctx := context.Background()
+
+	tests := []struct {
+		name  string
+		proxy Proxy
+	}{
+		{
+			name:  "userspace proxy",
+			proxy: udpProxy.NewWGUDPProxy(51830),
+		},
+	}
+
+	if runtime.GOOS == "linux" && os.Getenv("GITHUB_ACTIONS") != "true" {
+		ebpfProxy := ebpf.NewWGEBPFProxy(51831)
+		if err := ebpfProxy.Listen(); err != nil {
+			t.Fatalf("failed to initialize ebpf proxy: %s", err)
+		}
+		defer func() {
+			if err := ebpfProxy.Free(); err != nil {
+				t.Errorf("failed to free ebpf proxy: %s", err)
+			}
+		}()
+		proxyWrapper := &ebpf.ProxyWrapper{
+			WgeBPFProxy: ebpfProxy,
+		}
+
+		tests = append(tests, struct {
+			name  string
+			proxy Proxy
+		}{
+			name:  "ebpf proxy",
+			proxy: proxyWrapper,
+		})
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			relayedConn := newMockConn()
+			err := tt.proxy.AddTurnConn(ctx, nil, relayedConn)
+			if err != nil {
+				t.Errorf("error: %v", err)
+			}
+
+			_ = relayedConn.Close()
+			if err := tt.proxy.CloseConn(); err != nil {
+				t.Errorf("error: %v", err)
+			}
+		})
+	}
+}