tunnel setup stubs moved into Conn Read()/Write() handling

hkexnet/hkexnet.go

@@ -85,7 +85,7 @@ type (
 		Cols       uint16
 
 		chaff ChaffConfig
-		tuns  map[uint16]chan []byte
+		tuns  map[uint16]*TunEndpoint
 
 		closeStat *CSOType      // close status (CSOExitStatus)
 		r         cipher.Stream //read cipherStream
@@ -811,12 +811,16 @@ func (hc Conn) Read(b []byte) (n int, err error) {
 				}
 				hc.Close()
 			} else if ctrlStatOp == CSOTunSetup {
-				// Client wants a tunnel set up - args [lport:rport]
+				// server side tunnel setup in response to client
 				lport := binary.BigEndian.Uint16(payloadBytes)
 				rport := binary.BigEndian.Uint16(payloadBytes[2:4])
-				// spawn workers to listen for data and tunnel events
+				log.Printf("Tunnel setup [%d:%d]\r\n", lport, rport)
-				// via channel comms to hc.tuns[rport].tunCtl
+				StartServerTunnel(&hc, lport, rport)
-				startServerTunnel(&hc, lport, rport)
+			} else if ctrlStatOp == CSOTunSetupAck {
+				// client side has received ack from server
+				lport := binary.BigEndian.Uint16(payloadBytes)
+				rport := binary.BigEndian.Uint16(payloadBytes[2:4])
+				log.Printf("Tunnel ack [%d:%d]\r\n", lport, rport)
 			} else if ctrlStatOp == CSOTunData {
 				lport := binary.BigEndian.Uint16(payloadBytes)
 				rport := binary.BigEndian.Uint16(payloadBytes[2:4])
@@ -825,16 +829,7 @@ func (hc Conn) Read(b []byte) (n int, err error) {
 				if hc.tuns[rport] == nil {
 					fmt.Printf("[Invalid rport:%d]\r\n", rport)
 				} else {
-					hc.tuns[rport] <- payloadBytes[4:]
+					hc.tuns[rport].Data <- payloadBytes[4:]
-				}
-				//fmt.Printf("[Done stuffing hc.tuns[rport]\n")
-			} else if ctrlStatOp == CSOTunClose {
-				lport := binary.BigEndian.Uint16(payloadBytes)
-				rport := binary.BigEndian.Uint16(payloadBytes[2:4])
-				fmt.Printf("[Got CSOTunClose: [lport %d:rport %d]\r\n", lport, rport)
-				if hc.tuns[rport] != nil {
-					close(hc.tuns[rport])
-					hc.tuns[rport] = nil
 				}
 			} else {
 				hc.dBuf.Write(payloadBytes)
@@ -876,8 +871,8 @@ func (hc Conn) Write(b []byte) (n int, err error) {
 	return n, err
 }
 
-// Write a byte slice with specified ctrlStatusOp byte
+// Write a byte slice with specified ctrlStatOp byte
-func (hc *Conn) WritePacket(b []byte, op byte) (n int, err error) {
+func (hc *Conn) WritePacket(b []byte, ctrlStatOp byte) (n int, err error) {
 	//log.Printf("[Encrypting...]\r\n")
 	var hmacOut []uint8
 	var payloadLen uint32
@@ -886,7 +881,26 @@ func (hc *Conn) WritePacket(b []byte, op byte) (n int, err error) {
 		return 0, errors.New("Secure chan not ready for writing")
 	}
 
-	//Padding
+	if ctrlStatOp == CSOTunSetup {
+		// Client-side tunnel setup
+		lport := binary.BigEndian.Uint16(b)
+		rport := binary.BigEndian.Uint16(b[2:4])
+		// spawn workers to listen for data and tunnel events
+		// via channel comms to hc.tuns[rport].tunCtl
+		StartClientTunnel(hc, lport, rport)
+		// CSOTunSetup is written through to server side,
+		// see hc.Read()
+	} else if ctrlStatOp == CSOTunSetupAck {
+		lport := binary.BigEndian.Uint16(b)
+		rport := binary.BigEndian.Uint16(b[2:4])
+		if lport == 0 || rport == 0 {
+			log.Printf("Responded with tunnel setup nak [%d:%d]\r\n", lport, rport)
+		} else {
+			log.Printf("Responded with tunnel setup ack [%d:%d]\r\n", lport, rport)
+		}
+	}
+
+	//Padding prior to encryption
 	padSz := (rand.Intn(PAD_SZ) / 2) + (PAD_SZ / 2)
 	padLen := padSz - ((len(b) + padSz) % padSz)
 	if padLen == padSz {
@@ -938,7 +952,6 @@ func (hc *Conn) WritePacket(b []byte, op byte) (n int, err error) {
 	}
 	log.Printf("  ->ctext:\r\n%s\r\n", hex.Dump(wb.Bytes()))
 
-	ctrlStatOp := op
 	err = binary.Write(*hc.c, binary.BigEndian, &ctrlStatOp)
 	if err == nil {
 		// Write hmac LSB, payloadLen followed by payload

hkexnet/hkextun.go

@@ -11,12 +11,11 @@ package hkexnet
 import (
 	"bytes"
 	"encoding/binary"
-	"fmt"
+	//"fmt"
-	"io"
+	//"io"
-	"log"
+	//"log"
 	"net"
-
+	//"blitter.com/go/hkexsh/logger"
-	"blitter.com/go/hkexsh/logger"
 )
 
 type (
@@ -43,7 +42,8 @@ type (
 		Rport uint16      // Names are from client's perspective
 		Lport uint16      // ... ie., RPort is on server, LPort is on client
 		Peer  string      //net.Addr
-		tunCtl chan<- rune //See TunCtl_* consts
+		Ctl   chan<- rune //See TunCtl_* consts
+		Data  chan []byte
 	}
 
 	TunPacket struct {
@@ -52,104 +52,19 @@ type (
 	}
 )
 
-func startServerTunnel(hc *Conn, lport, rport uint16) {
-	if hc.tuns == nil {
-		hc.tuns = make(map[uint16]chan []byte)
-	}
-	if hc.tuns[rport] == nil {
-		hc.tuns[rport] = make(chan []byte, 32)
-	}
-
-	addrs, _ := net.InterfaceAddrs()
-	t := TunEndpoint{Peer: addrs[0].String(), Lport: lport, Rport: rport}
-	var resp bytes.Buffer
-	binary.Write(&resp, binary.BigEndian, t.Lport)
-
-	//var dialHangup chan<- bool
-
-	c, err := net.Dial("tcp", fmt.Sprintf(":%d", rport))
-	if err != nil {
-		logger.LogErr(fmt.Sprintf("Nothing is serving at rport :%d!", rport))
-		binary.Write(&resp, binary.BigEndian, uint16(0))
-		// Inform client of the tunPort
-		hc.WritePacket(resp.Bytes(), CSOTunRefused)
-	} else {
-		binary.Write(&resp, binary.BigEndian, t.Rport)
-		logger.LogNotice(fmt.Sprintf("[Tunnel Opened - %d:%s:%d]", t.Lport, t.Peer, t.Rport))
-
-		//
-		// worker to read data from the rport (to encrypt & send to client)
-		//
-		go func() {
-			defer func() {
-				//if hc.tuns[rport] != nil {
-				//	close(hc.tuns[rport])
-				//	hc.tuns[rport] = nil
-				//}
-				c.Close()
-			}()
-
-			var tunDst bytes.Buffer
-			binary.Write(&tunDst, binary.BigEndian, t.Lport)
-			binary.Write(&tunDst, binary.BigEndian, t.Rport)
-			for {
-				rBuf := make([]byte, 1024)
-				// Read data from c, encrypt/write via hc to client(lport)
-				n, e := c.Read(rBuf)
-				if e != nil {
-					if e == io.EOF {
-						logger.LogNotice(fmt.Sprintf("rport Disconnected: shutting down tunnel %v\n", t))
-					} else {
-						logger.LogErr(fmt.Sprintf("Read error from rport of tun %v\n%s", t, e))
-					}
-					hc.WritePacket(resp.Bytes(), CSOTunClose)
-					fmt.Printf("Closing server rport net.Dial()\n")
-					break
-				}
-				if n > 0 {
-					rBuf = append(tunDst.Bytes(), rBuf[:n]...)
-					logger.LogNotice(fmt.Sprintf("Got rport data:%v", tunDst.Bytes()))
-					hc.WritePacket(rBuf[:n+4], CSOTunData)
-				}
-			}
-		}()
-
-		// 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 := <-hc.tuns[rport]
-				if ok {
-					logger.LogNotice(fmt.Sprintf("Got client data:%v", rData))
-					c.Write(rData)
-				} else {
-					logger.LogErr("!!! ERROR reading from hc.tuns[] channel !!!")
-					break
-				}
-			}
-		}()
-
-		// Inform client of the tunPort
-		hc.WritePacket(resp.Bytes(), CSOTunAck)
-	}
-}
-
 func StartClientTunnel(hc *Conn, lport, rport uint16) {
-	go func() {
 	if hc.tuns == nil {
-			hc.tuns = make(map[uint16]chan []byte)
+		hc.tuns = make(map[uint16]*TunEndpoint)
 	}
 	if hc.tuns[rport] == nil {
-			hc.tuns[rport] = make(chan []byte, 32)
+		addrs, _ := net.InterfaceAddrs()
+		hc.tuns[rport] = &TunEndpoint{Peer: addrs[0].String(),
+			Lport: lport, Rport: rport, Ctl: make(chan<- rune)}
 	}
 
+	/*
+			 go func() {
+
 			l, e := net.Listen("tcp", fmt.Sprintf(":%d", lport))
 			if e != nil {
 				fmt.Printf("[Could not get lport %d! (%s)\n", lport, e)
@@ -226,4 +141,101 @@ func StartClientTunnel(hc *Conn, lport, rport uint16) {
 				}
 			}
 		}()
+	*/
+}
+
+func StartServerTunnel(hc *Conn, lport, rport uint16) {
+	if hc.tuns == nil {
+		hc.tuns = make(map[uint16]*TunEndpoint)
+	}
+	if hc.tuns[rport] == nil {
+		addrs, _ := net.InterfaceAddrs()
+		hc.tuns[rport] = &TunEndpoint{Peer: addrs[0].String(),
+			Lport: lport, Rport: rport, Ctl: make(chan<- rune)}
+	}
+
+	// Inform client of the tunPort
+	var resp bytes.Buffer
+	binary.Write(&resp, binary.BigEndian, hc.tuns[rport].Lport)
+	binary.Write(&resp, binary.BigEndian, hc.tuns[rport].Rport)
+	hc.WritePacket(resp.Bytes(), CSOTunSetupAck)
+
+	/*
+			t := TunEndpoint{Peer: addrs[0].String(), Lport: lport, Rport: rport}
+			var resp bytes.Buffer
+			binary.Write(&resp, binary.BigEndian, t.Lport)
+
+			//var dialHangup chan<- bool
+
+			c, err := net.Dial("tcp", fmt.Sprintf(":%d", rport))
+			if err != nil {
+				logger.LogErr(fmt.Sprintf("Nothing is serving at rport :%d!", rport))
+				binary.Write(&resp, binary.BigEndian, uint16(0))
+				// Inform client of the tunPort
+				hc.WritePacket(resp.Bytes(), CSOTunRefused)
+			} else {
+				binary.Write(&resp, binary.BigEndian, t.Rport)
+				logger.LogNotice(fmt.Sprintf("[Tunnel Opened - %d:%s:%d]", t.Lport, t.Peer, t.Rport))
+
+				//
+				// worker to read data from the rport (to encrypt & send to client)
+				//
+				go func() {
+					defer func() {
+						//if hc.tuns[rport] != nil {
+						//	close(hc.tuns[rport])
+						//	hc.tuns[rport] = nil
+						//}
+						c.Close()
+					}()
+
+					var tunDst bytes.Buffer
+					binary.Write(&tunDst, binary.BigEndian, t.Lport)
+					binary.Write(&tunDst, binary.BigEndian, t.Rport)
+					for {
+						rBuf := make([]byte, 1024)
+						// Read data from c, encrypt/write via hc to client(lport)
+						n, e := c.Read(rBuf)
+						if e != nil {
+							if e == io.EOF {
+								logger.LogNotice(fmt.Sprintf("rport Disconnected: shutting down tunnel %v\n", t))
+							} else {
+								logger.LogErr(fmt.Sprintf("Read error from rport of tun %v\n%s", t, e))
+							}
+							hc.WritePacket(resp.Bytes(), CSOTunClose)
+							fmt.Printf("Closing server rport net.Dial()\n")
+							break
+						}
+						if n > 0 {
+							rBuf = append(tunDst.Bytes(), rBuf[:n]...)
+							logger.LogNotice(fmt.Sprintf("Got rport data:%v", tunDst.Bytes()))
+							hc.WritePacket(rBuf[:n+4], CSOTunData)
+						}
+					}
+				}()
+
+				// 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 := <-hc.tuns[rport]
+						if ok {
+							logger.LogNotice(fmt.Sprintf("Got client data:%v", rData))
+							c.Write(rData)
+						} else {
+							logger.LogErr("!!! ERROR reading from hc.tuns[] channel !!!")
+							break
+						}
+					}
+				}()
+
+		}
+	*/
 }

hkexsh/hkexsh.go

@@ -340,24 +340,18 @@ func rejectUserMsg() string {
 // Transmit request to server for it to set up the remote end of a tunnel
 //
 // Server responds with [CSOTunAck:rport] or [CSOTunRefused:rport]
-func requestTunnel(hc *hkexnet.Conn, lp uint16, p string /*net.Addr*/, rp uint16) (t hkexnet.TunEndpoint) {
+// (handled in hkexnet.Read())
+func reqTunnel(hc *hkexnet.Conn, lp uint16, p string /*net.Addr*/, rp uint16) {
+	// Write request to server so it can attempt to set up its end
 	var bTmp bytes.Buffer
 	binary.Write(&bTmp, binary.BigEndian, lp)
 	binary.Write(&bTmp, binary.BigEndian, rp)
-	hc.WritePacket(bTmp.Bytes(), hkexnet.CSOTunReq)
+	hc.WritePacket(bTmp.Bytes(), hkexnet.CSOTunSetup)
+	// hkexnet.WritePacket() handles processing of client side tun setup,
+	// calling hkexnet.StartClientTunnel()
 
-	// Server should reply immediately with success (lport:rport) or
+	// Server should reply immediately with CSOTunSetupAck[lport:rport]
-	// refusal (lport:0)
+	// hkexnet.Read() on server side handles server side tun setup.
-	var lportReply, rportReply uint16
-	errL := binary.Read(hc, binary.BigEndian, &lportReply)
-	errR := binary.Read(hc, binary.BigEndian, &rportReply)
-	if errL == nil && errR == nil {
-		fmt.Printf("Server established tunnel [%d:%d]\r\n", lportReply, rportReply)
-		hkexnet.StartClientTunnel(hc, lp, rp)
-	} else {
-		fmt.Println("FAILED reading remPort")
-	}
-	t = hkexnet.TunEndpoint{Lport: lportReply, Peer: p, Rport: rportReply}
 	return
 }
 
@@ -648,12 +642,7 @@ func main() {
 		if shellMode {
 			// TESTING - tunnel
 			remAddrs, _ := net.LookupHost(remoteHost)
-			t := requestTunnel(&conn, 6001, remAddrs[0], 7001)
+			reqTunnel(&conn, 6001, remAddrs[0], 7001)
-			_ = t
-			//t := hkexnet.TunEndpoint{DataPort: 6001, Peer: nil, TunPort: 7001}
-			//var bTmp bytes.Buffer
-			//binary.Write(&bTmp, binary.BigEndian, t.DataPort)
-			//conn.WritePacket(bTmp.Bytes(), hkexnet.CSOTunReq)
 			// END TESTING - tunnel
 
 			doShellMode(isInteractive, &conn, oldState, rec)