mirror of https://gogs.blitter.com/RLabs/xs
Cleaned up error handling in hkexnet.Conn.Read() a bit
This commit is contained in:
Russ Magee
parent
e75ed159f6
commit
fcbdb77c79
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@ -685,10 +685,8 @@ func (hl *HKExListener) Accept() (hc Conn, err error) {
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//
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// See go doc io.Reader
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func (hc Conn) Read(b []byte) (n int, err error) {
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//log.Printf("[Decrypting...]\r\n")
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for {
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//log.Printf("hc.dBuf.Len(): %d\n", hc.dBuf.Len())
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if hc.dBuf.Len() > 0 /* len(b) */ {
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if hc.dBuf.Len() > 0 {
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break
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}
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@ -698,31 +696,52 @@ func (hc Conn) Read(b []byte) (n int, err error) {
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// Read ctrl/status opcode (CSOHmacInvalid on hmac mismatch)
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err = binary.Read(*hc.c, binary.BigEndian, &ctrlStatOp)
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if err != nil {
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if err.Error() == "EOF" {
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return 0, io.EOF
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}
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if strings.HasSuffix(err.Error(), "use of closed network connection") {
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logger.LogNotice(fmt.Sprintln("[Client hung up]"))
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return 0, io.EOF
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}
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etxt := fmt.Sprintf("** Failed read:%s (%s) **", "ctrlStatOp", err)
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logger.LogErr(etxt)
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return 0, errors.New(etxt)
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}
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log.Printf("[ctrlStatOp: %v]\n", ctrlStatOp)
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if ctrlStatOp == CSOHmacInvalid {
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// Other side indicated channel tampering, close channel
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hc.Close()
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return 1, errors.New("** ALERT - remote end detected HMAC mismatch - possible channel tampering **")
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return 0, errors.New("** ALERT - remote end detected HMAC mismatch - possible channel tampering **")
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}
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// Read the hmac and payload len first
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err = binary.Read(*hc.c, binary.BigEndian, &hmacIn)
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// Normal client 'exit' from interactive session will cause
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// (on server side) err.Error() == "<iface/addr info ...>: use of closed network connection"
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if err != nil {
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if err == io.EOF || strings.HasSuffix(err.Error(), "use of closed network connection") {
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logger.LogNotice(fmt.Sprintln("[Client hung up]"))
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} else {
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log.Println(err)
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if err.Error() == "EOF" {
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return 0, io.EOF
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}
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return 0, err
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if strings.HasSuffix(err.Error(), "use of closed network connection") {
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logger.LogNotice(fmt.Sprintln("[Client hung up]"))
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return 0, io.EOF
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}
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etxt := fmt.Sprintf("** Failed read:%s (%s) **", "HMAC", err)
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logger.LogErr(etxt)
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return 0, errors.New(etxt)
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}
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err = binary.Read(*hc.c, binary.BigEndian, &payloadLen)
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if err != nil {
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if err.Error() != "EOF" {
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logger.LogErr(fmt.Sprintln("[2]unexpected Read() err:", err))
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if err.Error() == "EOF" {
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return 0, io.EOF
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}
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if strings.HasSuffix(err.Error(), "use of closed network connection") {
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logger.LogNotice(fmt.Sprintln("[Client hung up]"))
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return 0, io.EOF
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}
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etxt := fmt.Sprintf("** Failed read:%s (%s) **", "payloadLen", err)
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logger.LogErr(etxt)
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return 0, errors.New(etxt)
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}
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if payloadLen > MAX_PAYLOAD_LEN {
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@ -733,15 +752,17 @@ func (hc Conn) Read(b []byte) (n int, err error) {
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var payloadBytes = make([]byte, payloadLen)
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n, err = io.ReadFull(*hc.c, payloadBytes)
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// Normal client 'exit' from interactive session will cause
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// (on server side) err.Error() == "<iface/addr info ...>: use of closed network connection"
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if err != nil && err.Error() != "EOF" {
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if !strings.HasSuffix(err.Error(), "use of closed network connection") {
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logger.LogErr(fmt.Sprintln("[3]unexpected Read() err:", err))
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} else {
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logger.LogNotice(fmt.Sprintln("[Client hung up]"))
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if err != nil {
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if err.Error() == "EOF" {
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return 0, io.EOF
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}
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if strings.HasSuffix(err.Error(), "use of closed network connection") {
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logger.LogNotice(fmt.Sprintln("[Client hung up]"))
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return 0, io.EOF
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}
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etxt := fmt.Sprintf("** Failed read:%s (%s) **", "payloadBytes", err)
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logger.LogErr(etxt)
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return 0, errors.New(etxt)
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}
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log.Printf(" <:ctext:\r\n%s\r\n", hex.Dump(payloadBytes[:n]))
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@ -797,19 +818,21 @@ func (hc Conn) Read(b []byte) (n int, err error) {
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} else if ctrlStatOp == CSOTunData {
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lport := binary.BigEndian.Uint16(payloadBytes)
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rport := binary.BigEndian.Uint16(payloadBytes[2:4])
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fmt.Printf("[Got CSOTunData: [lport %d:rport %d] data:%v\n", lport, rport, payloadBytes[4:])
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_ = lport
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//fmt.Printf("[Got CSOTunData: [lport %d:rport %d] data:%v\n", lport, rport, payloadBytes[4:])
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if hc.tuns[rport] == nil {
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fmt.Printf("[Invalid rport:%d]\n", rport)
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fmt.Printf("[Invalid rport:%d]\r\n", rport)
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} else {
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hc.tuns[rport] <- payloadBytes[4:]
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}
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fmt.Printf("[Done stuffing hc.tuns[rport]\n")
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//fmt.Printf("[Done stuffing hc.tuns[rport]\n")
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} else if ctrlStatOp == CSOTunClose {
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lport := binary.BigEndian.Uint16(payloadBytes)
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rport := binary.BigEndian.Uint16(payloadBytes[2:4])
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fmt.Printf("[Got CSOTunClose: [lport %d:rport %d]\n", lport, rport)
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fmt.Printf("[Got CSOTunClose: [lport %d:rport %d]\r\n", lport, rport)
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if hc.tuns[rport] != nil {
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close(hc.tuns[rport])
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hc.tuns[rport] = nil
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}
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} else {
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hc.dBuf.Write(payloadBytes)
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@ -0,0 +1,228 @@
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// hkextun.go - Tunnel setup using an established hkexnet.Conn
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// Copyright (c) 2017-2018 Russell Magee
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// Licensed under the terms of the MIT license (see LICENSE.mit in this
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// distribution)
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//
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// golang implementation by Russ Magee (rmagee_at_gmail.com)
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package hkexnet
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import (
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"bytes"
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"encoding/binary"
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"fmt"
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"io"
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"log"
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"net"
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"blitter.com/go/hkexsh/logger"
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)
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type (
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// Tunnels
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// --
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// 1. client is given (lport, remhost, rport) by local user
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// 2. client sends [CSOTunReq:rport] to server
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// client=> [CSOTunReq:rport] =>remhost
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//
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// remhost starts worker to receive/send data using rport
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// remhost replies to client with rport to acknowledge tun is ready
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// client<= [CSOTunAck:rport] <=remhost
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// ... or if rhost rport refuses connection, sends
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// [CSOTunRefused:rport]
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//
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// client starts worker to receive/send data using lport
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// ... client disconnects: sends remhost [CSOTunClose:rport]
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// ... or server disconnects: sends client [CSOTunClose:lport]
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// server at any time sends [CSOTunRefused:rport] if daemon died
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// --
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// TunEndpoint [securePort:peer:dataPort]
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TunEndpoint struct {
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Rport uint16 // Names are from client's perspective
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Lport uint16 // ... ie., RPort is on server, LPort is on client
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Peer string //net.Addr
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}
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TunPacket struct {
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n uint32
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data []byte
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}
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)
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func startServerTunnel(hc *Conn, lport, rport uint16) {
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if hc.tuns == nil {
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hc.tuns = make(map[uint16]chan []byte)
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}
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if hc.tuns[rport] == nil {
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hc.tuns[rport] = make(chan []byte, 32)
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}
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addrs, _ := net.InterfaceAddrs()
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t := TunEndpoint{Peer: addrs[0].String(), Lport: lport, Rport: rport}
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var resp bytes.Buffer
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binary.Write(&resp, binary.BigEndian, t.Lport)
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//var dialHangup chan<- bool
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c, err := net.Dial("tcp", fmt.Sprintf(":%d", rport))
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if err != nil {
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logger.LogErr(fmt.Sprintf("Nothing is serving at rport :%d!", rport))
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binary.Write(&resp, binary.BigEndian, uint16(0))
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// Inform client of the tunPort
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hc.WritePacket(resp.Bytes(), CSOTunRefused)
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} else {
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binary.Write(&resp, binary.BigEndian, t.Rport)
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logger.LogNotice(fmt.Sprintf("[Tunnel Opened - %d:%s:%d]", t.Lport, t.Peer, t.Rport))
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//
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// worker to read data from the rport (to encrypt & send to client)
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//
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go func() {
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defer func() {
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//if hc.tuns[rport] != nil {
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// close(hc.tuns[rport])
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// hc.tuns[rport] = nil
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//}
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c.Close()
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}()
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var tunDst bytes.Buffer
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binary.Write(&tunDst, binary.BigEndian, t.Lport)
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binary.Write(&tunDst, binary.BigEndian, t.Rport)
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for {
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rBuf := make([]byte, 1024)
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// Read data from c, encrypt/write via hc to client(lport)
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n, e := c.Read(rBuf)
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if e != nil {
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if e == io.EOF {
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logger.LogNotice(fmt.Sprintf("rport Disconnected: shutting down tunnel %v\n", t))
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} else {
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logger.LogErr(fmt.Sprintf("Read error from rport of tun %v\n%s", t, e))
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}
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hc.WritePacket(resp.Bytes(), CSOTunClose)
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fmt.Printf("Closing server rport net.Dial()\n")
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break
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}
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if n > 0 {
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rBuf = append(tunDst.Bytes(), rBuf[:n]...)
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logger.LogNotice(fmt.Sprintf("Got rport data:%v", tunDst.Bytes()))
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hc.WritePacket(rBuf[:n+4], CSOTunData)
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}
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}
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}()
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// worker to read data from client (already decrypted) & fwd to rport
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go func() {
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defer func() {
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//if hc.tuns[rport] != nil {
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//close(hc.tuns[rport])
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//hc.tuns[rport] = nil
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//}
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c.Close()
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}()
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for {
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rData, ok := <-hc.tuns[rport]
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if ok {
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logger.LogNotice(fmt.Sprintf("Got client data:%v", rData))
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c.Write(rData)
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} else {
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logger.LogErr("!!! ERROR reading from hc.tuns[] channel !!!")
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break
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}
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}
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}()
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// Inform client of the tunPort
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hc.WritePacket(resp.Bytes(), CSOTunAck)
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}
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}
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func StartClientTunnel(hc *Conn, lport, rport uint16) {
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go func() {
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if hc.tuns == nil {
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hc.tuns = make(map[uint16]chan []byte)
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}
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if hc.tuns[rport] == nil {
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hc.tuns[rport] = make(chan []byte, 32)
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}
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l, e := net.Listen("tcp", fmt.Sprintf(":%d", lport))
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if e != nil {
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fmt.Printf("[Could not get lport %d! (%s)\n", lport, e)
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} else {
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defer l.Close()
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for {
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c, e := l.Accept()
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defer func() {
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//if hc.tuns[rport] != nil {
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// close(hc.tuns[rport])
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// hc.tuns[rport] = nil
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//}
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c.Close()
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}()
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if e != nil {
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log.Printf("Accept() got error(%v), hanging up.\n", e)
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break
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//log.Fatal(err)
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} else {
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log.Println("Accepted client")
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// outside client -> tunnel lport
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go func() {
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var tunDst bytes.Buffer
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binary.Write(&tunDst, binary.BigEndian, lport)
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binary.Write(&tunDst, binary.BigEndian, rport)
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for {
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rBuf := make([]byte, 1024)
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//Read data from c, encrypt/write via hc to client(lport)
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n, e := c.Read(rBuf)
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if e != nil {
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if e == io.EOF {
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logger.LogNotice(fmt.Sprintf("lport Disconnected: shutting down tunnel [%d:%d]\n", lport, rport))
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} else {
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logger.LogErr(fmt.Sprintf("Read error from lport of tun [%d:%d]\n%s", lport, rport, e))
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}
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hc.WritePacket(tunDst.Bytes(), CSOTunClose)
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break
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}
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if n > 0 {
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rBuf = append(tunDst.Bytes(), rBuf[:n]...)
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logger.LogNotice(fmt.Sprintf("Got lport data:%v\n", tunDst.Bytes()))
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hc.WritePacket(rBuf[:n+4], CSOTunData)
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}
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}
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}()
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// tunnel lport -> outside client (c)
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go func() {
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defer func() {
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//if hc.tuns[rport] != nil {
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// close(hc.tuns[rport])
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// hc.tuns[rport] = nil
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//}
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c.Close()
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}()
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for {
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//fmt.Printf("Reading from client hc.tuns[%d]\n", lport)
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bytes, ok := <-hc.tuns[rport]
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if ok {
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//fmt.Printf("[Got this through tunnel:%v]\n", bytes)
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c.Write(bytes)
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} else {
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fmt.Printf("[Channel closed? exiting client worker!]\n")
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break
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}
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}
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}()
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}
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}
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}
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}()
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}
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@ -352,7 +352,7 @@ func requestTunnel(hc *hkexnet.Conn, lp uint16, p string /*net.Addr*/, rp uint16
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errL := binary.Read(hc, binary.BigEndian, &lportReply)
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errR := binary.Read(hc, binary.BigEndian, &rportReply)
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if errL == nil && errR == nil {
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fmt.Printf("Server established tunnel [%d:%d]\n", lportReply, rportReply)
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fmt.Printf("Server established tunnel [%d:%d]\r\n", lportReply, rportReply)
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hkexnet.StartClientTunnel(hc, lp, rp)
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} else {
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fmt.Println("FAILED reading remPort")
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