transx/tcp.go

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package main
import (
"bytes"
"crypto/md5"
"encoding/hex"
"github.com/TransX/log"
"github.com/TransX/tscipher"
"net"
"os"
"strconv"
"sync/atomic"
"time"
)
type TransTCP struct {
seed int32
}
func NewTransTCP() *TransTCP {
return &TransTCP{
0,
}
}
func (this *TransTCP) createTCPClient(ip, port string) (conn net.Conn, err error) {
conn, err = net.Dial("tcp4", ip+":"+port)
if err == nil {
} else {
conn = nil
}
return
}
func (this *TransTCP) createTCPListener(ip, port string) (listen net.Listener, err error) {
listener, _err := net.Listen("tcp4", ip+":"+port)
if _err == nil {
listen = listener
err = nil
return
} else {
listen = nil
err = _err
}
return
}
func (this *TransTCP) tunnel(src, dest net.Conn, id string) {
defer func() {
if r := recover(); r != nil {
if src != nil {
src.Close()
}
if dest != nil {
dest.Close()
}
}
}()
cache := make([]byte, 1024*128) //128kB
for {
//构建Carrier
revCarrier := &tscipher.Carrier{
src,
tscipher.NewCipher("XOR"),
cache,
}
nByte, err := tscipher.ReceiveData(revCarrier)
if err != nil {
log.Panic("Read panic", id, err, src.RemoteAddr().String())
}
log.Info("Reived ", nByte, "bytes:", id, string(cache[:nByte]))
sendCarrier := &tscipher.Carrier{
dest,
tscipher.NewCipher("XOR"),
cache, //TODO:危险cache的容量容易被不小心修改
}
_, err = tscipher.SendData(sendCarrier, nByte)
log.Info("Write")
if err != nil {
log.Panic("Write panic", id, err, dest.RemoteAddr().String())
}
}
}
func (this *TransTCP) tunnelID() string {
nowString := time.Now().String() + strconv.Itoa(int(this.seed))
atomic.AddInt32(&this.seed, 1) //避免多线程情况下获得的种子相同
md5Byte := md5.Sum(bytes.NewBufferString(nowString).Bytes())
return hex.EncodeToString(md5Byte[:])
}
func (this *TransTCP) Start(listenPort, destIP, destPort string) {
listener, err := this.createTCPListener("0.0.0.0", listenPort)
if err != nil {
log.Panic("Failed to create listener.", err)
os.Exit(0)
}
for {
if listenerConn, err := listener.Accept(); err == nil {
log.Info("Incoming ", listenerConn.RemoteAddr().String())
//创建到目标的连接
destConn, err := this.createTCPClient(destIP, destPort)
if err != nil {
log.Panic("Failed to connect to destination.", err)
os.Exit(0)
}
log.Info("Dial", destConn.RemoteAddr().String())
go this.tunnel(listenerConn, destConn, this.tunnelID())
go this.tunnel(destConn, listenerConn, this.tunnelID())
} else {
log.Info("Failed to accept incoming connection.", err)
}
}
}