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Tun2Pipe.go
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Tun2Pipe.go
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package tun2Pipe
import (
"fmt"
"github.com/google/gopacket"
"github.com/google/gopacket/layers"
"io"
"math"
"net"
"strconv"
"sync"
"time"
)
const (
SysDialTimeOut = time.Second * 2
UDPSessionTimeOut = time.Second * 80
MTU = math.MaxInt16
InnerPivotPort = 51414 //TODO:: this port should be refactored
)
type Tun2Pipe struct {
sync.RWMutex
innerTcpPivot *net.TCPListener
SessionCache map[int]*Session
udpProxy *UdpProxy
youPipeProxy int
tunIP net.IP
}
type VpnDelegate interface {
ByPass(fd int32) bool
io.Writer
Log(str string) //TODO::variadic function
}
var VpnInstance VpnDelegate = nil
type ConnProtect func(fd uintptr)
var Protector ConnProtect
func New(proxyAddr string) (*Tun2Pipe, error) {
l, e := net.ListenTCP("tcp", &net.TCPAddr{
Port: InnerPivotPort,
})
if e != nil {
return nil, e
}
ip, port, _ := net.SplitHostPort(proxyAddr)
intPort, _ := strconv.Atoi(port)
tsc := &Tun2Pipe{
innerTcpPivot: l,
SessionCache: make(map[int]*Session),
udpProxy: NewUdpProxy(),
tunIP: net.ParseIP(ip),
youPipeProxy: intPort,
}
return tsc, nil
}
func (t2s *Tun2Pipe) Proxying(done chan error) {
for {
conn, err := t2s.innerTcpPivot.Accept()
if err != nil {
VpnInstance.Log(fmt.Sprintln("Tun2proxy inner pivot accept:", err))
done <- err
return
}
go t2s.simpleForward(conn)
select {
case err := <-done:
VpnInstance.Log(err.Error())
default:
}
}
}
func (t2s *Tun2Pipe) GetTarget(conn net.Conn) string {
keyPort := conn.RemoteAddr().(*net.TCPAddr).Port
s := t2s.GetSession(keyPort)
if s == nil {
return ""
}
if len(s.HostName) != 0 {
return fmt.Sprintf("%s:%d", s.HostName, s.RemotePort)
}
addr := &net.TCPAddr{
IP: s.RemoteIP,
Port: s.RemotePort,
}
return addr.String()
}
func (t2s *Tun2Pipe) InputPacket(buf []byte) {
var ip4 *layers.IPv4 = nil
packet := gopacket.NewPacket(buf, layers.LayerTypeIPv4, gopacket.Default)
//VpnInstance.Log(packet.Dump())
if ip4Layer := packet.Layer(layers.LayerTypeIPv4); ip4Layer != nil {
ip4 = ip4Layer.(*layers.IPv4)
} else {
VpnInstance.Log("Unsupported network layer :")
return
}
var tcp *layers.TCP = nil
if tcpLayer := packet.Layer(layers.LayerTypeTCP); tcpLayer != nil {
tcp = tcpLayer.(*layers.TCP)
t2s.ProcessTcpPacket(ip4, tcp)
return
}
var udp *layers.UDP = nil
if udpLayer := packet.Layer(layers.LayerTypeUDP); udpLayer != nil {
udp = udpLayer.(*layers.UDP)
t2s.udpProxy.ReceivePacket(ip4, udp)
return
}
VpnInstance.Log(fmt.Sprintf("Unsupported transport layer :%s", ip4.Protocol.String()))
}
func (t2s *Tun2Pipe) Finish() {
t2s.Lock()
defer t2s.Unlock()
if t2s.innerTcpPivot != nil {
t2s.innerTcpPivot.Close()
t2s.innerTcpPivot = nil
}
if t2s.udpProxy.Done != nil {
t2s.udpProxy.Done <- fmt.Errorf("finished by outer controller")
}
}
func (t2s *Tun2Pipe) RemoveFromSession(keyPort int) {
t2s.RemoveSession(keyPort)
}
func (t2s *Tun2Pipe) tun2Proxy(ip4 *layers.IPv4, tcp *layers.TCP) {
//PrintFlow("-=->tun2Proxy", ip4, tcp)
srcPort := int(tcp.SrcPort)
s := t2s.GetSession(srcPort)
if s == nil {
var srvPort = InnerPivotPort
bypass := ByPassInst().Hit(ip4.DstIP)
if !bypass {
srvPort = t2s.youPipeProxy
VpnInstance.Log(fmt.Sprintln("This session will be proxy:", ip4.DstIP, tcp.DstPort, srcPort))
}
s = newSession(ip4, tcp, srvPort, bypass)
t2s.AddSession(srcPort, s)
}
tcpLen := len(tcp.Payload)
s.UPTime = time.Now()
s.packetSent++
if s.packetSent == 2 && tcpLen == 0 {
VpnInstance.Log(fmt.Sprintf("Discard the ack:%t\n syn:%t psh:%t", tcp.ACK, tcp.SYN, tcp.PSH))
return
}
if s.byteSent == 0 && tcpLen > 10 {
host := ParseHost(tcp.Payload)
if len(host) > 0 {
VpnInstance.Log(fmt.Sprintln("Session host success:", host))
s.HostName = host
}
}
ip4.SrcIP = ip4.DstIP
ip4.DstIP = t2s.tunIP
tcp.DstPort = layers.TCPPort(s.ServerPort)
data := ChangePacket(ip4, tcp)
//PrintFlow("-=->tun2Proxy", ip4, tcp)
if _, err := VpnInstance.Write(data); err != nil {
VpnInstance.Log(fmt.Sprintln("-=->tun2Proxy write to tun err:", err))
return
}
s.byteSent += tcpLen
}
func (t2s *Tun2Pipe) proxy2Tun(ip4 *layers.IPv4, tcp *layers.TCP, rPort int) {
//PrintFlow("<-=-proxy2Tun", ip4, tcp)
ip4.SrcIP = ip4.DstIP
ip4.DstIP = t2s.tunIP
tcp.SrcPort = layers.TCPPort(rPort)
data := ChangePacket(ip4, tcp)
//PrintFlow("<-=-proxy2Tun", ip4, tcp)
if _, err := VpnInstance.Write(data); err != nil {
VpnInstance.Log(fmt.Sprintln("<-=-proxy2Tun write to tun err:", err))
return
}
}
func (t2s *Tun2Pipe) ProcessTcpPacket(ip4 *layers.IPv4, tcp *layers.TCP) {
srcPort := int(tcp.SrcPort)
if srcPort == InnerPivotPort ||
srcPort == t2s.youPipeProxy {
dstPort := int(tcp.DstPort)
if s := t2s.GetSession(dstPort); s != nil {
t2s.proxy2Tun(ip4, tcp, s.RemotePort)
}
return
}
t2s.tun2Proxy(ip4, tcp)
}
func (t2s *Tun2Pipe) GetSession(key int) *Session {
t2s.RLock()
defer t2s.RUnlock()
return t2s.SessionCache[key]
}
func (t2s *Tun2Pipe) AddSession(portKey int, s *Session) {
t2s.Lock()
defer t2s.Unlock()
t2s.SessionCache[portKey] = s
}
func (t2s *Tun2Pipe) RemoveSession(key int) {
t2s.Lock()
defer t2s.Unlock()
delete(t2s.SessionCache, key)
}