// Currently one client acceping will block all other clients' request
func (ln *TCPListener) AcceptTCP() (conn *TCPConn, err error) {
var c net.Conn
for {
c, err = ln.Listener.Accept()
if err != nil {
glog.Errorln("fail to accept from listener", err)
return conn, err
}
// in case idle connection session being cleaned by NAT server
if err = c.(*net.TCPConn).SetKeepAlive(true); err != nil {
glog.Errorln("fail to set keep alive", err)
return
}
req := request{}
if err := recieve(ln.cipher, c, &req); err != nil {
glog.Errorln("fail to recieve request", err)
continue
}
if req.Secret != ln.secret {
send(ln.cipher, c, response{Status: StatusInvalidSecret})
continue
}
ip, err := ln.ipAddrPool.Get()
if err != nil {
send(ln.cipher, c, response{Status: StatusNoIPAddrAvaliable})
continue
}
conn = &TCPConn{
remoteAddr: ip.IP.To4(),
listener: ln,
}
conn.cipher, err = cipher.NewCipher(req.Key[:])
if err != nil {
return conn, err
}
res := response{
Status: StatusOK,
}
copy(res.IP[:], ip.IP.To4())
copy(res.IPMask[:], ip.Mask)
send(ln.cipher, c, &res)
conn.Conn = c
return conn, err
}
}
func ListenTCP(secret, localAddr string, internalIP net.IP, ipNet *net.IPNet) (ln *TCPListener, err error) {
ln = &TCPListener{}
ln.Listener, err = net.Listen("tcp", localAddr)
if err != nil {
return
}
ln.cipher, err = cipher.NewCipher([]byte(secret))
if err != nil {
return
}
ln.ipAddrPool = NewIPAddrPool(internalIP, ipNet)
ln.secret = sha256.Sum256([]byte(secret))
return
}
func DialTCP(secret, remoteAddr string) (conn *TCPConn, err error) {
c, err := net.Dial("tcp", remoteAddr)
if err != nil {
glog.Errorln("fail to dial to server", err, remoteAddr)
return
}
// in case idle connection session being cleaned by NAT server
if err = c.(*net.TCPConn).SetKeepAlive(true); err != nil {
glog.Errorln("fail to set keep alive", err)
return
}
cph, err := cipher.NewCipher([]byte(secret))
if err != nil {
return
}
key := make([]byte, cipher.KeySize)
if _, err = io.ReadFull(rand.Reader, key); err != nil {
return
}
req := request{
Secret: sha256.Sum256([]byte(secret)),
}
copy(req.Key[:], key)
if err = send(cph, c, &req); err != nil {
glog.Error("fail to send request", err)
return
}
res := response{}
if err = recieve(cph, c, &res); err != nil {
glog.Error("fail to recieve response", err)
return
}
switch res.Status {
case StatusOK:
case StatusUnknowErr:
fallthrough
case StatusInvalidSecret:
err = ErrInvalidSecret
return
case StatusInvalidProto:
err = ErrInvalidProto
return
case StatusNoIPAddrAvaliable:
err = ErrNoIPAddrAvaliable
return
default:
err = ErrUnknowErr
return
}
// Initialize conn
conn = &TCPConn{
localAddr: res.IP[:],
ipNetMask: res.IPMask[:],
}
conn.Conn = c
conn.cipher, err = cipher.NewCipher(key)
return
}