code refactor for common package

pkg/common/util/socks/conn.go

@@ -0,0 +1,174 @@
+package socks
+
+import (
+	"bytes"
+	"net"
+
+	"github.com/go-gost/gosocks5"
+	"github.com/go-gost/gost/pkg/common/bufpool"
+)
+
+var (
+	_ net.PacketConn = (*UDPTunConn)(nil)
+	_ net.Conn       = (*UDPTunConn)(nil)
+
+	_ net.PacketConn = (*UDPConn)(nil)
+	_ net.Conn       = (*UDPConn)(nil)
+)
+
+type UDPTunConn struct {
+	net.Conn
+	taddr net.Addr
+}
+
+func UDPTunClientConn(c net.Conn, targetAddr net.Addr) *UDPTunConn {
+	return &UDPTunConn{
+		Conn:  c,
+		taddr: targetAddr,
+	}
+}
+
+func UDPTunServerConn(c net.Conn) *UDPTunConn {
+	return &UDPTunConn{
+		Conn: c,
+	}
+}
+
+func (c *UDPTunConn) ReadFrom(b []byte) (n int, addr net.Addr, err error) {
+	socksAddr := gosocks5.Addr{}
+	header := gosocks5.UDPHeader{
+		Addr: &socksAddr,
+	}
+	dgram := gosocks5.UDPDatagram{
+		Header: &header,
+		Data:   b,
+	}
+	_, err = dgram.ReadFrom(c.Conn)
+	if err != nil {
+		return
+	}
+
+	n = len(dgram.Data)
+	if n > len(b) {
+		n = copy(b, dgram.Data)
+	}
+	addr, err = net.ResolveUDPAddr("udp", socksAddr.String())
+
+	return
+}
+
+func (c *UDPTunConn) Read(b []byte) (n int, err error) {
+	n, _, err = c.ReadFrom(b)
+	return
+}
+
+func (c *UDPTunConn) WriteTo(b []byte, addr net.Addr) (n int, err error) {
+	socksAddr := gosocks5.Addr{}
+	if err = socksAddr.ParseFrom(addr.String()); err != nil {
+		return
+	}
+
+	header := gosocks5.UDPHeader{
+		Addr: &socksAddr,
+	}
+	dgram := gosocks5.UDPDatagram{
+		Header: &header,
+		Data:   b,
+	}
+	dgram.Header.Rsv = uint16(len(dgram.Data))
+	dgram.Header.Frag = 0xff // UDP tun relay flag, used by shadowsocks
+	_, err = dgram.WriteTo(c.Conn)
+	n = len(b)
+
+	return
+}
+
+func (c *UDPTunConn) Write(b []byte) (n int, err error) {
+	return c.WriteTo(b, c.taddr)
+}
+
+var (
+	DefaultBufferSize = 4096
+)
+
+type UDPConn struct {
+	net.PacketConn
+	raddr      net.Addr
+	taddr      net.Addr
+	bufferSize int
+}
+
+func NewUDPConn(c net.PacketConn, bufferSize int) *UDPConn {
+	return &UDPConn{
+		PacketConn: c,
+		bufferSize: bufferSize,
+	}
+}
+
+// ReadFrom reads an UDP datagram.
+// NOTE: for server side,
+// the returned addr is the target address the client want to relay to.
+func (c *UDPConn) ReadFrom(b []byte) (n int, addr net.Addr, err error) {
+	rbuf := bufpool.Get(c.bufferSize)
+	defer bufpool.Put(rbuf)
+
+	n, c.raddr, err = c.PacketConn.ReadFrom(rbuf)
+	if err != nil {
+		return
+	}
+
+	socksAddr := gosocks5.Addr{}
+	header := gosocks5.UDPHeader{
+		Addr: &socksAddr,
+	}
+	hlen, err := header.ReadFrom(bytes.NewReader(rbuf[:n]))
+	if err != nil {
+		return
+	}
+	n = copy(b, rbuf[hlen:n])
+
+	addr, err = net.ResolveUDPAddr("udp", socksAddr.String())
+	return
+}
+
+func (c *UDPConn) Read(b []byte) (n int, err error) {
+	n, _, err = c.ReadFrom(b)
+	return
+}
+
+func (c *UDPConn) WriteTo(b []byte, addr net.Addr) (n int, err error) {
+	wbuf := bufpool.Get(c.bufferSize)
+	defer bufpool.Put(wbuf)
+
+	socksAddr := gosocks5.Addr{}
+	if err = socksAddr.ParseFrom(addr.String()); err != nil {
+		return
+	}
+
+	header := gosocks5.UDPHeader{
+		Addr: &socksAddr,
+	}
+	dgram := gosocks5.UDPDatagram{
+		Header: &header,
+		Data:   b,
+	}
+
+	buf := bytes.NewBuffer(wbuf[:0])
+	_, err = dgram.WriteTo(buf)
+	if err != nil {
+		return
+	}
+
+	_, err = c.PacketConn.WriteTo(buf.Bytes(), c.raddr)
+	n = len(b)
+
+	return
+}
+
+func (c *UDPConn) Write(b []byte) (n int, err error) {
+	return c.WriteTo(b, c.taddr)
+}
+
+func (c *UDPConn) RemoteAddr() net.Addr {
+	return c.raddr
+}

pkg/common/util/socks/socks.go

@@ -0,0 +1,18 @@
+package socks
+
+const (
+	// MethodTLS is an extended SOCKS5 method with tls encryption support.
+	MethodTLS uint8 = 0x80
+	// MethodTLSAuth is an extended SOCKS5 method with tls encryption and authentication support.
+	MethodTLSAuth uint8 = 0x82
+	// MethodMux is an extended SOCKS5 method for stream multiplexing.
+	MethodMux = 0x88
+)
+
+const (
+	// CmdMuxBind is an extended SOCKS5 request CMD for
+	// multiplexing transport with the binding server.
+	CmdMuxBind uint8 = 0xF2
+	// CmdUDPTun is an extended SOCKS5 request CMD for UDP over TCP.
+	CmdUDPTun uint8 = 0xF3
+)