src/cypherpunks.ru/govpn/client/tcp.go

   1 /*
   2 GoVPN -- simple secure free software virtual private network daemon
   3 Copyright (C) 2014-2017 Sergey Matveev <stargrave@stargrave.org>
   4
   5 This program is free software: you can redistribute it and/or modify
   6 it under the terms of the GNU General Public License as published by
   7 the Free Software Foundation, either version 3 of the License, or
   8 (at your option) any later version.
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU General Public License for more details.
  14
  15 You should have received a copy of the GNU General Public License
  16 along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17 */
  18
  19 package client
  20
  21 import (
  22         "bytes"
  23         "fmt"
  24         "net"
  25         "sync/atomic"
  26         "time"
  27
  28         "cypherpunks.ru/govpn"
  29 )
  30
  31 func (c *Client) startTCP() {
  32         remote, err := net.ResolveTCPAddr("tcp", c.config.RemoteAddress)
  33         if err != nil {
  34                 c.Error <- fmt.Errorf("Can not resolve remote address: %s", err)
  35                 return
  36         }
  37         conn, err := net.DialTCP("tcp", nil, remote)
  38         if err != nil {
  39                 c.Error <- fmt.Errorf("Can not connect to address: %s", err)
  40                 return
  41         }
  42         govpn.Printf(`[connected remote="%s"]`, c.config.RemoteAddress)
  43         c.handleTCP(conn)
  44 }
  45
  46 func (c *Client) handleTCP(conn *net.TCPConn) {
  47         hs := govpn.HandshakeStart(c.config.RemoteAddress, conn, c.config.Peer)
  48         buf := make([]byte, 2*(govpn.EnclessEnlargeSize+c.config.MTU)+c.config.MTU)
  49         var n int
  50         var err error
  51         var prev int
  52         var peer *govpn.Peer
  53         var terminator chan struct{}
  54 HandshakeCycle:
  55         for {
  56                 select {
  57                 case <-c.termination:
  58                         break HandshakeCycle
  59                 default:
  60                 }
  61                 if prev == len(buf) {
  62                         govpn.Printf(`[packet-timeouted remote="%s"]`, c.config.RemoteAddress)
  63                         c.timeouted <- struct{}{}
  64                         break HandshakeCycle
  65                 }
  66
  67                 if err = conn.SetReadDeadline(time.Now().Add(c.config.Peer.Timeout)); err != nil {
  68                         c.Error <- err
  69                         break HandshakeCycle
  70                 }
  71                 n, err = conn.Read(buf[prev:])
  72                 if err != nil {
  73                         govpn.Printf(`[connection-timeouted remote="%s"]`, c.config.RemoteAddress)
  74                         c.timeouted <- struct{}{}
  75                         break HandshakeCycle
  76                 }
  77
  78                 prev += n
  79                 peerID := c.idsCache.Find(buf[:prev])
  80                 if peerID == nil {
  81                         continue
  82                 }
  83                 peer = hs.Client(buf[:prev])
  84                 prev = 0
  85                 if peer == nil {
  86                         continue
  87                 }
  88                 govpn.Printf(`[handshake-completed remote="%s"]`, c.config.RemoteAddress)
  89                 c.knownPeers = govpn.KnownPeers(map[string]**govpn.Peer{c.config.RemoteAddress: &peer})
  90                 if c.firstUpCall {
  91                         go govpn.ScriptCall(c.config.UpPath, c.config.InterfaceName, c.config.RemoteAddress)
  92                         c.firstUpCall = false
  93                 }
  94                 hs.Zero()
  95                 terminator = make(chan struct{})
  96                 go govpn.PeerTapProcessor(peer, c.tap, terminator)
  97                 break HandshakeCycle
  98         }
  99         if hs != nil {
 100                 hs.Zero()
 101         }
 102         if peer == nil {
 103                 return
 104         }
 105
 106         prev = 0
 107         var i int
 108 TransportCycle:
 109         for {
 110                 select {
 111                 case <-c.termination:
 112                         break TransportCycle
 113                 default:
 114                 }
 115                 if prev == len(buf) {
 116                         govpn.Printf(`[packet-timeouted remote="%s"]`, c.config.RemoteAddress)
 117                         c.timeouted <- struct{}{}
 118                         break TransportCycle
 119                 }
 120                 if err = conn.SetReadDeadline(time.Now().Add(c.config.Peer.Timeout)); err != nil {
 121                         c.Error <- err
 122                         break TransportCycle
 123                 }
 124                 n, err = conn.Read(buf[prev:])
 125                 if err != nil {
 126                         govpn.Printf(`[connection-timeouted remote="%s"]`, c.config.RemoteAddress)
 127                         c.timeouted <- struct{}{}
 128                         break TransportCycle
 129                 }
 130                 prev += n
 131         CheckMore:
 132                 if prev < govpn.MinPktLength {
 133                         continue
 134                 }
 135                 i = bytes.Index(buf[:prev], peer.NonceExpect)
 136                 if i == -1 {
 137                         continue
 138                 }
 139                 if !peer.PktProcess(buf[:i+govpn.NonceSize], c.tap, false) {
 140                         govpn.Printf(`[packet-unauthenticated remote="%s"]`, c.config.RemoteAddress)
 141                         c.timeouted <- struct{}{}
 142                         break TransportCycle
 143                 }
 144                 if atomic.LoadUint64(&peer.BytesIn)+atomic.LoadUint64(&peer.BytesOut) > govpn.MaxBytesPerKey {
 145                         govpn.Printf(`[rehandshake-required remote="%s"]`, c.config.RemoteAddress)
 146                         c.rehandshaking <- struct{}{}
 147                         break TransportCycle
 148                 }
 149                 copy(buf, buf[i+govpn.NonceSize:prev])
 150                 prev = prev - i - govpn.NonceSize
 151                 goto CheckMore
 152         }
 153         if terminator != nil {
 154                 terminator <- struct{}{}
 155         }
 156         peer.Zero()
 157         if err = conn.Close(); err != nil {
 158                 c.Error <- err
 159         }
 160 }