Feature: add tunnels

listener/tunnel/packet.go

@@ -0,0 +1,31 @@
+package tunnel
+
+import (
+	"net"
+
+	"github.com/Dreamacro/clash/common/pool"
+)
+
+type packet struct {
+	pc      net.PacketConn
+	rAddr   net.Addr
+	payload []byte
+}
+
+func (c *packet) Data() []byte {
+	return c.payload
+}
+
+// WriteBack write UDP packet with source(ip, port) = `addr`
+func (c *packet) WriteBack(b []byte, addr net.Addr) (n int, err error) {
+	return c.pc.WriteTo(b, c.rAddr)
+}
+
+// LocalAddr returns the source IP/Port of UDP Packet
+func (c *packet) LocalAddr() net.Addr {
+	return c.rAddr
+}
+
+func (c *packet) Drop() {
+	pool.Put(c.payload)
+}

listener/tunnel/tcp.go

@@ -0,0 +1,75 @@
+package tunnel
+
+import (
+	"fmt"
+	"net"
+
+	"github.com/Dreamacro/clash/adapter/inbound"
+	C "github.com/Dreamacro/clash/constant"
+	"github.com/Dreamacro/clash/transport/socks5"
+)
+
+type Listener struct {
+	listener net.Listener
+	addr     string
+	target   socks5.Addr
+	proxy    string
+	closed   bool
+}
+
+// RawAddress implements C.Listener
+func (l *Listener) RawAddress() string {
+	return l.addr
+}
+
+// Address implements C.Listener
+func (l *Listener) Address() string {
+	return l.listener.Addr().String()
+}
+
+// Close implements C.Listener
+func (l *Listener) Close() error {
+	l.closed = true
+	return l.listener.Close()
+}
+
+func (l *Listener) handleTCP(conn net.Conn, in chan<- C.ConnContext) {
+	conn.(*net.TCPConn).SetKeepAlive(true)
+	ctx := inbound.NewSocket(l.target, conn, C.TUNNEL)
+	ctx.Metadata().SpecialProxy = l.proxy
+	in <- ctx
+}
+
+func New(addr, target, proxy string, in chan<- C.ConnContext) (*Listener, error) {
+	l, err := net.Listen("tcp", addr)
+	if err != nil {
+		return nil, err
+	}
+
+	targetAddr := socks5.ParseAddr(target)
+	if targetAddr == nil {
+		return nil, fmt.Errorf("invalid target address %s", target)
+	}
+
+	rl := &Listener{
+		listener: l,
+		target:   targetAddr,
+		proxy:    proxy,
+		addr:     addr,
+	}
+
+	go func() {
+		for {
+			c, err := l.Accept()
+			if err != nil {
+				if rl.closed {
+					break
+				}
+				continue
+			}
+			go rl.handleTCP(c, in)
+		}
+	}()
+
+	return rl, nil
+}

listener/tunnel/udp.go

@@ -0,0 +1,85 @@
+package tunnel
+
+import (
+	"fmt"
+	"net"
+
+	"github.com/Dreamacro/clash/adapter/inbound"
+	"github.com/Dreamacro/clash/common/pool"
+	C "github.com/Dreamacro/clash/constant"
+	"github.com/Dreamacro/clash/transport/socks5"
+)
+
+type PacketConn struct {
+	conn   net.PacketConn
+	addr   string
+	target socks5.Addr
+	proxy  string
+	closed bool
+}
+
+// RawAddress implements C.Listener
+func (l *PacketConn) RawAddress() string {
+	return l.addr
+}
+
+// Address implements C.Listener
+func (l *PacketConn) Address() string {
+	return l.conn.LocalAddr().String()
+}
+
+// Close implements C.Listener
+func (l *PacketConn) Close() error {
+	l.closed = true
+	return l.conn.Close()
+}
+
+func NewUDP(addr, target, proxy string, in chan<- *inbound.PacketAdapter) (*PacketConn, error) {
+	l, err := net.ListenPacket("udp", addr)
+	if err != nil {
+		return nil, err
+	}
+
+	targetAddr := socks5.ParseAddr(target)
+	if targetAddr == nil {
+		return nil, fmt.Errorf("invalid target address %s", target)
+	}
+
+	sl := &PacketConn{
+		conn:   l,
+		target: targetAddr,
+		proxy:  proxy,
+		addr:   addr,
+	}
+	go func() {
+		for {
+			buf := pool.Get(pool.UDPBufferSize)
+			n, remoteAddr, err := l.ReadFrom(buf)
+			if err != nil {
+				pool.Put(buf)
+				if sl.closed {
+					break
+				}
+				continue
+			}
+			sl.handleUDP(l, in, buf[:n], remoteAddr)
+		}
+	}()
+
+	return sl, nil
+}
+
+func (l *PacketConn) handleUDP(pc net.PacketConn, in chan<- *inbound.PacketAdapter, buf []byte, addr net.Addr) {
+	packet := &packet{
+		pc:      pc,
+		rAddr:   addr,
+		payload: buf,
+	}
+
+	ctx := inbound.NewPacket(l.target, packet, C.TUNNEL)
+	ctx.Metadata().SpecialProxy = l.proxy
+	select {
+	case in <- ctx:
+	default:
+	}
+}