src/govpn/cmd/govpn-client/udp.go

   1 /*
   2 GoVPN -- simple secure free software virtual private network daemon
   3 Copyright (C) 2014-2015 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 main
  20
  21 import (
  22         "log"
  23         "net"
  24         "sync/atomic"
  25         "time"
  26
  27         "govpn"
  28 )
  29
  30 func startUDP(timeouted, rehandshaking, termination chan struct{}) {
  31         remote, err := net.ResolveUDPAddr("udp", *remoteAddr)
  32         if err != nil {
  33                 log.Fatalln("Can not resolve remote address:", err)
  34         }
  35         conn, err := net.DialUDP("udp", nil, remote)
  36         if err != nil {
  37                 log.Fatalln("Can not listen on UDP:", err)
  38         }
  39
  40         hs := govpn.HandshakeStart(*remoteAddr, conn, conf)
  41         buf := make([]byte, govpn.MTU)
  42         var n int
  43         var timeouts int
  44         var peer *govpn.Peer
  45         var terminator chan struct{}
  46 MainCycle:
  47         for {
  48                 select {
  49                 case <-termination:
  50                         break MainCycle
  51                 default:
  52                 }
  53
  54                 conn.SetReadDeadline(time.Now().Add(time.Second))
  55                 n, err = conn.Read(buf)
  56                 if timeouts == timeout {
  57                         log.Println("Timeouted")
  58                         timeouted <- struct{}{}
  59                         break
  60                 }
  61                 if err != nil {
  62                         timeouts++
  63                         continue
  64                 }
  65                 if peer != nil {
  66                         if peer.PktProcess(buf[:n], tap, true) {
  67                                 timeouts = 0
  68                         } else {
  69                                 timeouts++
  70                         }
  71                         if atomic.LoadInt64(&peer.BytesIn)+atomic.LoadInt64(&peer.BytesOut) > govpn.MaxBytesPerKey {
  72                                 log.Println("Need rehandshake")
  73                                 terminator <- struct{}{}
  74                                 terminator = nil
  75                                 rehandshaking <- struct{}{}
  76                                 break MainCycle
  77                         }
  78                         continue
  79                 }
  80                 if govpn.IDsCache.Find(buf[:n]) == nil {
  81                         log.Println("Invalid identity in handshake packet")
  82                         continue
  83                 }
  84                 timeouts = 0
  85                 peer = hs.Client(buf[:n])
  86                 if peer == nil {
  87                         continue
  88                 }
  89                 log.Println("Handshake completed")
  90                 knownPeers = govpn.KnownPeers(map[string]**govpn.Peer{*remoteAddr: &peer})
  91                 if firstUpCall {
  92                         go govpn.ScriptCall(*upPath, *ifaceName)
  93                         firstUpCall = false
  94                 }
  95                 hs.Zero()
  96                 terminator = make(chan struct{})
  97                 go func() {
  98                         heartbeat := time.NewTicker(peer.Timeout)
  99                         var data []byte
 100                 Processor:
 101                         for {
 102                                 select {
 103                                 case <-heartbeat.C:
 104                                         peer.EthProcess(nil)
 105                                 case <-terminator:
 106                                         break Processor
 107                                 case data = <-tap.Sink:
 108                                         peer.EthProcess(data)
 109                                 }
 110                         }
 111                         heartbeat.Stop()
 112                         peer.Zero()
 113                 }()
 114         }
 115         if terminator != nil {
 116                 terminator <- struct{}{}
 117         }
 118         if hs != nil {
 119                 hs.Zero()
 120         }
 121 }