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conn.go
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conn.go
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package gocks5
import (
"bufio"
"errors"
"fmt"
"net"
"strconv"
"github.com/yulon/go-netil"
)
type Conn struct {
net.Conn
br *bufio.Reader
}
func newConn(rawCon net.Conn) *Conn {
return &Conn{rawCon, bufio.NewReader(rawCon)}
}
func (con *Conn) Read(p []byte) (n int, err error) {
return con.br.Read(p)
}
func (con *Conn) WriteAddr(typ byte, addr net.Addr) error {
/*
+----+-----+-------+------+----------+------+
|VER | TYP | RSV | ATYP | ADDR | PORT |
+----+-----+-------+------+----------+------+
| 1 | 1 | X'00' | 1 | Variable | 2 |
+----+-----+-------+------+----------+------+
*/
return netil.WriteAll(con, append([]byte{Ver, typ, 0}, AddrToBytes(addr)...))
}
var ErrorUnknowAddress = errors.New("unknow address")
func (con *Conn) ReadAddr() (byte, net.Addr, error) {
var vtra [4]byte
err := netil.ReadFull(con, vtra[:])
if err != nil {
return 0, nil, err
}
switch vtra[3] {
case AtypIPv4:
var addrBytes [6]byte
err := netil.ReadFull(con, addrBytes[:])
if err != nil {
return vtra[1], nil, err
}
return vtra[1], &netil.IPPortAddr{
IP: net.IPv4(addrBytes[0], addrBytes[1], addrBytes[2], addrBytes[3]),
Port: (int(addrBytes[4]) << 8) | int(addrBytes[5]),
}, nil
case AtypIPv6:
var addrBytes [18]byte
err := netil.ReadFull(con, addrBytes[:])
if err != nil {
return vtra[1], nil, err
}
return vtra[1], &netil.IPPortAddr{
IP: addrBytes[:16],
Port: (int(addrBytes[16]) << 8) | int(addrBytes[17]),
}, nil
case AtypDomain:
var domainLenBuf [1]byte
err := netil.ReadFull(con, domainLenBuf[:])
if err != nil {
return vtra[1], nil, err
}
domainLen := int(domainLenBuf[0])
addrBytes := make([]byte, domainLen+2)
err = netil.ReadFull(con, addrBytes)
if err != nil {
return vtra[1], nil, err
}
return vtra[1], netil.DomainAddr(string(addrBytes[:domainLen]) + ":" + strconv.Itoa((int(addrBytes[domainLen])<<8)|int(addrBytes[domainLen+1]))), nil
}
return vtra[1], nil, ErrorUnknowAddress
}
func makeUDPPacket(addr net.Addr, data []byte) []byte {
addrByts := AddrToBytes(addr)
if len(addrByts) == 0 {
return nil
}
return append([]byte{0, 0, 0}, append(addrByts, data...)...)
}
func makeUDPHeaderToBack(b []byte, addr net.Addr) int {
n := AddrToBytesBack(b, addr)
if n == 0 {
return 0
}
lst := len(b) - 1 - n
b[lst-2] = 0
b[lst-1] = 0
b[lst] = 0
return 3 + n
}
var ErrorUnsupportedUDPFragment = errors.New("unsupported UDP fragments")
func parseUDPPacket(p []byte) (net.Addr, []byte, error) {
if p[0] != 0 || p[1] != 0 {
return nil, nil, fmt.Errorf("unsupported UDP package header, %+v", int(p[0])<<8|int(p[1]))
}
if p[2] != 0 {
return nil, nil, ErrorUnsupportedUDPFragment
}
p = p[3:]
switch p[0] {
case AtypIPv4:
return &net.UDPAddr{
IP: net.IPv4(p[1], p[2], p[3], p[4]),
Port: (int(p[5]) << 8) | int(p[6]),
}, p[7:], nil
case AtypIPv6:
return &net.UDPAddr{
IP: p[1:17],
Port: (int(p[17]) << 8) | int(p[18]),
}, p[19:], nil
case AtypDomain:
domainLen := int(p[1])
return netil.DomainAddr(string(p[2:domainLen]) + ":" + strconv.Itoa((int(p[2+domainLen])<<8)|int(p[3+domainLen]))), p[4+domainLen:], nil
}
return nil, nil, ErrorUnknowAddress
}
type packetConn struct {
net.PacketConn
pxyAddr net.Addr
keepAliveCon net.Conn
}
func newPacketConn(rawCon net.PacketConn, pxyAddr net.Addr, keepAliveCon net.Conn) *packetConn {
return &packetConn{rawCon, pxyAddr, keepAliveCon}
}
func (pcon *packetConn) ReadFrom(b []byte) (n int, raddr net.Addr, err error) {
n, _, raddr, err = pcon.ReadFromForward(b)
return
}
func (pcon *packetConn) WriteTo(data []byte, raddr net.Addr) (int, error) {
return pcon.WriteToForward(data, pcon.pxyAddr, raddr)
}
func (pcon *packetConn) Close() error {
err := pcon.PacketConn.Close()
if pcon.keepAliveCon == nil {
return err
}
if err != nil {
pcon.keepAliveCon.Close()
return err
}
return pcon.keepAliveCon.Close()
}
func (pcon *packetConn) RemoteAddr() net.Addr {
return pcon.pxyAddr
}
func (pcon *packetConn) ReadFromForward(b []byte) (n int, raddr, faddr net.Addr, err error) {
var data []byte
for {
n, faddr, err = pcon.PacketConn.ReadFrom(b)
if err != nil {
return
}
raddr, data, err = parseUDPPacket(b[:n])
if err == nil {
break
}
}
n = copy(b, data)
return
}
func (pcon *packetConn) WriteToForward(data []byte, raddr, faddr net.Addr) (int, error) {
pkt := makeUDPPacket(raddr, data)
if len(pkt) == 0 {
return 0, ErrorAddressNotSupported
}
return pcon.PacketConn.WriteTo(pkt, faddr)
}