Much improved tunnel state management: server-side mostly working, client-side re-Accept() -> svr re-Dial() still required

hkexnet/hkexnet.go

@@ -816,6 +816,7 @@ func (hc Conn) Read(b []byte) (n int, err error) {
 				rport := binary.BigEndian.Uint16(payloadBytes[2:4])
 				logger.LogDebug(fmt.Sprintf("Read(): Tunnel setup [%d:%d]", lport, rport))
 				hc.StartServerTunnel(lport, rport)
+				hc.tuns[rport].Ctl <- 'a' // Dial() rport
 			} else if ctrlStatOp == CSOTunSetupAck {
 				lport := binary.BigEndian.Uint16(payloadBytes[0:2])
 				rport := binary.BigEndian.Uint16(payloadBytes[2:4])
@@ -826,22 +827,29 @@ func (hc Conn) Read(b []byte) (n int, err error) {
 				lport := binary.BigEndian.Uint16(payloadBytes[0:2])
 				rport := binary.BigEndian.Uint16(payloadBytes[2:4])
 				logger.LogDebug(fmt.Sprintf("Read(): Tunnel refused [%d:%d]", lport, rport))
+				hc.dBuf.Write(payloadBytes)
 			} else if ctrlStatOp == CSOTunDisconn {
 				// server side's rport has disconnected (server lost)
 				lport := binary.BigEndian.Uint16(payloadBytes[0:2])
 				rport := binary.BigEndian.Uint16(payloadBytes[2:4])
 				logger.LogDebug(fmt.Sprintf("Read(): Tunnel server disconnected [%d:%d]", lport, rport))
+				hc.dBuf.Write(payloadBytes)
 			} else if ctrlStatOp == CSOTunHangup {
 				// client side's lport has hung up
 				lport := binary.BigEndian.Uint16(payloadBytes[0:2])
 				rport := binary.BigEndian.Uint16(payloadBytes[2:4])
 				logger.LogDebug(fmt.Sprintf("Read(): Tunnel client hung up [%d:%d]", lport, rport))
+				hc.dBuf.Write(payloadBytes)
 			} else if ctrlStatOp == CSOTunData {
 				lport := binary.BigEndian.Uint16(payloadBytes[0:2])
 				rport := binary.BigEndian.Uint16(payloadBytes[2:4])
 				//fmt.Printf("[Got CSOTunData: [lport %d:rport %d] data:%v\n", lport, rport, payloadBytes[4:])
-				logger.LogDebug(fmt.Sprintf("[Writing data to rport [%d:%d] %v", lport, rport, payloadBytes[4:]))
+				if hc.tuns[rport] != nil {
-				hc.tuns[rport].Data <- payloadBytes[4:]
+					logger.LogDebug(fmt.Sprintf("[Writing data to rport [%d:%d]", lport, rport))
+					hc.tuns[rport].Data <- payloadBytes[4:]
+				} else {
+					logger.LogDebug(fmt.Sprintf("[Attempt to write data to closed tun [%d:%d]", lport, rport))
+				}
 			} else if ctrlStatOp == CSONone {
 				hc.dBuf.Write(payloadBytes)
 			} else {

hkexnet/hkextun.go

@@ -39,18 +39,12 @@ type (
 
 	// TunEndpoint [securePort:peer:dataPort]
 	TunEndpoint struct {
-		Rport  uint16      // Names are from client's perspective
+		Rport uint16    // Names are from client's perspective
-		Lport  uint16      // ... ie., RPort is on server, LPort is on client
+		Lport uint16    // ... ie., RPort is on server, LPort is on client
-		Peer   string      //net.Addr
+		Peer  string    //net.Addr
-		//Status byte        //Last status of tunnel (eg., CSOTunSetupAck)
+		Ctl   chan rune //See TunCtl_* consts
-		Ctl    chan<- rune //See TunCtl_* consts
+		Data  chan []byte
-		Data   chan []byte
 	}
-
-	//TunPacket struct {
-	//	n    uint32
-	//	data []byte
-	//}
 )
 
 func (hc *Conn) InitTunEndpoint(lp uint16, p string /* net.Addr */, rp uint16) {
@@ -63,23 +57,19 @@ func (hc *Conn) InitTunEndpoint(lp uint16, p string /* net.Addr */, rp uint16) {
 			addrs, _ = net.InterfaceAddrs()
 			p = addrs[0].String()
 		}
-		hc.tuns[rp] = &TunEndpoint{/*Status: CSOTunSetup,*/ Peer: p,
+		hc.tuns[rp] = &TunEndpoint{ /*Status: CSOTunSetup,*/ Peer: p,
-				Lport: lp, Rport: rp, Data: make(chan[]byte, 32), Ctl: make(chan<- rune)}
+			Lport: lp, Rport: rp, Data: make(chan []byte, 1),
+			Ctl: make(chan rune, 1)}
 		logger.LogDebug(fmt.Sprintf("InitTunEndpoint [%d:%s:%d]\n", lp, p, rp))
 	}
 	return
 }
 
-//func (hc *Conn) GetTunStatus(rp uint16) byte {
-//	return hc.tuns[rp].Status
-//}
-
 func (hc *Conn) StartClientTunnel(lport, rport uint16) {
 	hc.InitTunEndpoint(lport, "", rport)
 	t := hc.tuns[rport] // for convenience
 
 	go func() {
-
 		logger.LogDebug(fmt.Sprintf("Listening for client tunnel port %d", lport))
 		l, e := net.Listen("tcp", fmt.Sprintf(":%d", lport))
 		if e != nil {
@@ -90,17 +80,12 @@ func (hc *Conn) StartClientTunnel(lport, rport uint16) {
 				c, e := l.Accept()
 
 				defer func() {
-					//if hc.tuns[rport] != nil {
-					//	close(hc.tuns[rport])
-					//	hc.tuns[rport] = nil
-					//}
 					c.Close()
 				}()
 
 				if e != nil {
 					logger.LogDebug(fmt.Sprintf("Accept() got error(%v), hanging up.", e))
 					break
-					//log.Fatal(err)
 				} else {
 					logger.LogDebug(fmt.Sprintln("Accepted tunnel client"))
 
@@ -124,7 +109,6 @@ func (hc *Conn) StartClientTunnel(lport, rport uint16) {
 							}
 							if n > 0 {
 								rBuf = append(tunDst.Bytes(), rBuf[:n]...)
-								//logger.LogDebug(fmt.Sprintf("Got lport data:%v", tunDst.Bytes()))
 								hc.WritePacket(rBuf[:n+4], CSOTunData)
 							}
 						}
@@ -133,22 +117,16 @@ func (hc *Conn) StartClientTunnel(lport, rport uint16) {
 					// tunnel lport -> outside client (c)
 					go func() {
 						defer func() {
-							//if hc.tuns[rport] != nil {
-							//	close(hc.tuns[rport])
-							//	hc.tuns[rport] = nil
-							//}
 							c.Close()
 						}()
 
 						for {
-							//fmt.Printf("Reading from client hc.tuns[%d]\n", lport)
 							bytes, ok := <-t.Data
 							if ok {
-								//fmt.Printf("[Got this through tunnel:%v]\n", bytes)
 								c.Write(bytes)
 							} else {
 								logger.LogDebug(fmt.Sprintf("[Channel closed?]\n"))
-								//break
+								break
 							}
 						}
 					}()
@@ -163,12 +141,16 @@ func (hc *Conn) StartServerTunnel(lport, rport uint16) {
 	hc.InitTunEndpoint(lport, "", rport)
 	t := hc.tuns[rport] // for convenience
 
+	//go func() {
+	//	for cmd := range t.Ctl {
+	//		var c net.Conn
+	//		if cmd == 'a' {
 	logger.LogDebug("Server dialling...")
 	c, err := net.Dial("tcp", fmt.Sprintf(":%d", rport))
 	if err != nil {
 		logger.LogDebug(fmt.Sprintf("Nothing is serving at rport :%d!", rport))
 		var resp bytes.Buffer
-		binary.Write(&resp, binary.BigEndian, lport)
+		binary.Write(&resp, binary.BigEndian, /*lport*/uint16(0))
 		binary.Write(&resp, binary.BigEndian, rport)
 		hc.WritePacket(resp.Bytes(), CSOTunRefused)
 	} else {
@@ -184,10 +166,6 @@ func (hc *Conn) StartServerTunnel(lport, rport uint16) {
 		//
 		go func() {
 			defer func() {
-				//if hc.tuns[rport] != nil {
-				//	close(hc.tuns[rport])
-				//	hc.tuns[rport] = nil
-				//}
 				c.Close()
 			}()
 
@@ -221,23 +199,27 @@ func (hc *Conn) StartServerTunnel(lport, rport uint16) {
 		// worker to read data from client (already decrypted) & fwd to rport
 		go func() {
 			defer func() {
-				//if hc.tuns[rport] != nil {
-				//close(hc.tuns[rport])
-				//hc.tuns[rport] = nil
-				//}
 				c.Close()
 			}()
 
 			for {
 				rData, ok := <-t.Data
 				if ok {
-					//logger.LogDebug(fmt.Sprintf("Got client data:%v", rData))
 					c.Write(rData)
 				} else {
-					logger.LogDebug("!!! ERROR reading from hc.tuns[] channel !!!")
+					logger.LogDebug("[ERROR reading from hc.tuns[] channel - closed?]")
 					break
 				}
 			}
 		}()
 	}
+	//		} else if cmd == 'h' {
+	//			logger.LogDebug("[Server hanging up on rport on behalf of client]")
+	//			c.Close()
+	//		} else {
+	//			logger.LogDebug("[ERR: this should be unreachable]")
+	//		}
+	//	} // t.Ctl read loop
+	//	logger.LogDebug("[ServerTunnel() exiting t.Ctl read loop - channel closed??]")
+	//}()
 }

hkexsh/hkexsh.go

@@ -349,18 +349,9 @@ func reqTunnel(hc *hkexnet.Conn, lp uint16, p string /*net.Addr*/, rp uint16) {
 	fmt.Printf("bTmp:%x\n", bTmp.Bytes())
 	logger.LogDebug(fmt.Sprintln("[Client sending CSOTunSetup]"))
 	hc.WritePacket(bTmp.Bytes(), hkexnet.CSOTunSetup)
-	// hkexnet.WritePacket() handles processing of client side tun setup,
+	
-	// calling hkexnet.StartClientTunnel()
-
 	// Server should reply immediately with CSOTunSetupAck[lport:rport]
 	// hkexnet.Read() on server side handles server side tun setup.
-
-	// CSOTun packets don't reply with acks/naks in the datastream; they
-	// record the last status (other than CSOTunData) in the TunEndpoint
-	// .Status field. We can check this here to determine how the request
-	// completed.
-	// TODO: Should be a timeout check here of course to avoid hangs...
-	hc.InitTunEndpoint(lp, p, rp)
 	resp := make([]byte, 4)
 	var lpResp, rpResp uint16
 	n, e := io.ReadFull(hc, resp)
@@ -369,15 +360,6 @@ func reqTunnel(hc *hkexnet.Conn, lp uint16, p string /*net.Addr*/, rp uint16) {
 	} else {
 		lpResp = binary.BigEndian.Uint16(resp[0:2])
 		rpResp = binary.BigEndian.Uint16(resp[2:4])
-		//var s byte
-		//for timeout := 0; timeout < 5; timeout++ {
-		//	s = hc.GetTunStatus(rp)
-		//	if s != hkexnet.CSOTunSetup {
-		//		logger.LogDebug(fmt.Sprintf("[Client tun setup result:%d\n]", s))
-		//		break
-		//	}
-		//	time.Sleep(1 * time.Second)
-		//}
 	}
 
 	if lpResp == lp && rpResp == rp {