code refactor for common package

pkg/common/util/ss/conn.go

@@ -0,0 +1,96 @@
+package ss
+
+import (
+	"bytes"
+	"net"
+
+	"github.com/go-gost/gosocks5"
+	"github.com/go-gost/gost/pkg/common/bufpool"
+)
+
+var (
+	DefaultBufferSize = 4096
+)
+
+var (
+	_ net.PacketConn = (*UDPConn)(nil)
+	_ net.Conn       = (*UDPConn)(nil)
+)
+
+type UDPConn struct {
+	net.PacketConn
+	raddr      net.Addr
+	taddr      net.Addr
+	bufferSize int
+}
+
+func UDPClientConn(c net.PacketConn, remoteAddr, targetAddr net.Addr, bufferSize int) *UDPConn {
+	return &UDPConn{
+		PacketConn: c,
+		raddr:      remoteAddr,
+		taddr:      targetAddr,
+		bufferSize: bufferSize,
+	}
+}
+
+func UDPServerConn(c net.PacketConn, remoteAddr net.Addr, bufferSize int) *UDPConn {
+	return &UDPConn{
+		PacketConn: c,
+		raddr:      remoteAddr,
+		bufferSize: bufferSize,
+	}
+}
+
+func (c *UDPConn) ReadFrom(b []byte) (n int, addr net.Addr, err error) {
+	rbuf := bufpool.Get(c.bufferSize)
+	defer bufpool.Put(rbuf)
+
+	n, _, err = c.PacketConn.ReadFrom(rbuf)
+	if err != nil {
+		return
+	}
+
+	saddr := gosocks5.Addr{}
+	addrLen, err := saddr.ReadFrom(bytes.NewReader(rbuf[:n]))
+	if err != nil {
+		return
+	}
+
+	n = copy(b, rbuf[addrLen:n])
+	addr, err = net.ResolveUDPAddr("udp", saddr.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
+	}
+
+	addrLen, err := socksAddr.Encode(wbuf)
+	if err != nil {
+		return
+	}
+
+	n = copy(wbuf[addrLen:], b)
+	_, err = c.PacketConn.WriteTo(wbuf[:addrLen+n], c.raddr)
+
+	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
+}