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nat.go
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nat.go
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package nat
import (
"errors"
"net"
"strings"
"time"
"github.com/vzex/dog-tunnel/nat/stun"
)
func Init(outIpList string, buster bool, id int, udpAddr string) (*AttemptEngine, error) {
sock, err := net.ListenUDP("udp", &net.UDPAddr{})
if err != nil {
return nil, err
}
engine := &AttemptEngine{sock: sock, buster: buster, id: id}
if err := engine.init(outIpList, udpAddr); err != nil {
return nil, err
}
return engine, nil
}
type attempt struct {
candidate
tid []byte
timeout time.Time
success bool // did we get a STUN response from this addr
chosen bool // Has this channel been picked for the connection?
localaddr net.Addr
}
type AttemptEngine struct {
id int
buster bool
sock *net.UDPConn
attempts []attempt
local_attempts []attempt
p2pconn net.Conn
otherReady bool
status string
Kcp *KcpSetting
D, P int
}
const probeTimeout = 500 * time.Millisecond
const probeInterval = 100 * time.Millisecond
const decisionTime = 2 * time.Second
func (e *AttemptEngine) SetOtherAddrList(addrList string) {
arr := strings.Split(addrList, "\n")
e.attempts = make([]attempt, 0)
for _, addrStr := range arr {
if addrStr != "" {
addr, err := net.ResolveUDPAddr("udp", addrStr)
if err != nil {
debug("resolve udp addr err", err.Error())
} else {
e.attempts = append(e.attempts, attempt{candidate: candidate{Addr: addr}})
}
}
}
}
func (e *AttemptEngine) GetAddrList() string {
tmp := ""
for _, attempt := range e.local_attempts {
tmp += attempt.Addr.String() + "\n"
}
return tmp
}
func (e *AttemptEngine) Fail() {
e.status = "quit"
if e.sock != nil {
//debug("close udp sock")
e.sock.Close()
}
}
func (e *AttemptEngine) GetConn(f func(), encode, decode func([]byte) []byte) (net.Conn, error) {
var conn net.Conn
var err error
if conn, err = e.run(f, encode, decode); err != nil {
return nil, err
}
return conn, nil
}
func (e *AttemptEngine) init(outIpList string, udpAddr string) error {
candidates, err := GatherCandidates(e.sock, outIpList, udpAddr)
if err != nil {
return err
}
e.local_attempts = make([]attempt, len(candidates))
for i := range candidates {
e.local_attempts[i].candidate = candidates[i]
debug("init addr", candidates[i].Addr.String())
}
e.sock.SetWriteDeadline(time.Time{})
return nil
}
func (e *AttemptEngine) xmit() (time.Time, error) {
now := time.Now()
var ret time.Time
var err error
if e.p2pconn != nil {
return ret, nil
}
for i := range e.attempts {
if e.attempts[i].timeout.Before(now) {
e.attempts[i].timeout = time.Now().Add(probeTimeout)
e.attempts[i].tid, err = stun.RandomTid()
if err != nil {
return time.Time{}, err
}
packet, err := stun.BindRequest(e.attempts[i].tid, e.attempts[i].Addr, nil, false, e.attempts[i].chosen)
if err != nil {
return time.Time{}, err
}
//debug("===send", i,e.attempts[i].Addr.String())
e.sock.WriteToUDP(packet, e.attempts[i].Addr)
for j := range e.local_attempts {
if e.local_attempts[j].success {
packet, err := stun.BindRequest(e.attempts[i].tid, e.attempts[i].Addr, nil, false, e.attempts[i].chosen)
if err != nil {
return time.Time{}, err
}
//debug("===send local", i,e.local_attempts[j].localaddr.String())
e.sock.WriteToUDP(packet, e.local_attempts[j].localaddr.(*net.UDPAddr))
}
}
}
if ret.IsZero() || e.attempts[i].timeout.Before(ret) {
ret = e.attempts[i].timeout
}
}
return ret, nil
}
func (e *AttemptEngine) read() error {
if e.status == "over" {
return nil
}
buf := make([]byte, 512)
n, from, err := e.sock.ReadFromUDP(buf)
//println("read", n, from, err)
if err != nil {
if neterr, ok := err.(net.Error); ok && neterr.Timeout() {
return nil
}
return err
}
if string(buf[0:n]) == "makeholeover" {
if e.status == "wait" {
debug("wait client !!!!!!! close")
e.status = "over"
e.sock.WriteToUDP([]byte("makeholeover2"), from)
}
return nil
}
if string(buf[0:n]) == "makeholeover2" {
if e.status == "wait" {
debug("wait server !!!!!!! close")
e.status = "over"
}
return nil
}
//debug("========", string(buf[0:n]))
packet, err := stun.ParsePacket(buf[:n], nil)
if err != nil {
return nil
}
if packet.Method != stun.MethodBinding {
return nil
}
validAddr := packet.Addr
for i := range e.local_attempts {
my_local_addr := e.local_attempts[i].Addr
//debug("check local",i, validAddr.String(), packet.Class, from.String(), my_local_addr.String())
if validAddr.String() == my_local_addr.String() {
e.local_attempts[i].localaddr = from
e.local_attempts[i].success = true
//debug("find the addr from request", packet.Class, from.String())
if packet.Class == stun.ClassRequest {
for j := range e.attempts {
my_remote_addr := e.attempts[j].Addr
response, err := stun.BindResponse(packet.Tid[:], my_remote_addr, nil, false)
if err != nil {
return nil
}
debug("write to succ", from.String(), j, my_remote_addr.String())
e.sock.WriteToUDP(response, from)
}
} else if packet.Class == stun.ClassSuccess {
if e.p2pconn == nil {
debug("make conn success", from.String(), e.local_attempts[i].localaddr.String())
e.p2pconn = newConn(e.sock, e.local_attempts[i].Addr, e.local_attempts[i].localaddr, e.id)
if e.Kcp != nil {
e.p2pconn.(*Conn).SetKcp(e.Kcp)
}
if e.D > 0 && e.P > 0 {
e.p2pconn.(*Conn).SetFec(e.D, e.P)
}
for j := range e.attempts {
my_remote_addr := e.attempts[j].Addr
response, err := stun.InformReady(packet.Tid[:], my_remote_addr, nil)
if err != nil {
return nil
}
debug("write to ready", from.String(), j, my_remote_addr.String())
e.sock.WriteToUDP(response, from)
}
}
} else if packet.Class == stun.ClassIndication {
debug("recv other ready")
e.otherReady = true
/* for j := range e.attempts {
debug("write !!!!!!", from.String(),j)
e.sock.WriteToUDP([]byte("wocao,okokokook1!!"), from)
}*/
} else if packet.Class == stun.ClassError {
// debug("!!!!!!!!!!!!!")
}
}
}
return nil
}
func (e *AttemptEngine) run(f func(), encode, decode func([]byte) []byte) (net.Conn, error) {
bInform := false
beginTime := time.Now().Unix()
for {
if time.Now().Unix()-beginTime > 10 {
e.status = "fail"
}
if e.status == "fail" || e.status == "quit" {
break
}
timeout, err := e.xmit()
if err != nil {
return nil, err
}
if !bInform {
f()
bInform = true
beginTime = time.Now().Unix()
}
e.sock.SetReadDeadline(timeout)
if err = e.read(); err != nil {
//return nil, err
}
if e.p2pconn != nil && e.otherReady {
if e.buster && e.status == "" {
debug("write final!!!!!!")
e.sock.WriteToUDP([]byte("makeholeover"), e.p2pconn.RemoteAddr().(*net.UDPAddr))
}
if e.status != "over" {
e.status = "wait"
}
}
if e.status == "over" {
e.p2pconn.(*Conn).SetCrypt(encode, decode)
e.p2pconn.(*Conn).Run()
return e.p2pconn, nil
}
}
return nil, errors.New(e.status)
}