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         log.Println("Connected to UDP:" + *remoteAddr)
  40
  41         hs := govpn.HandshakeStart(*remoteAddr, conn, conf)
  42         buf := make([]byte, govpn.MTU)
  43         var n int
  44         var timeouts int
  45         var peer *govpn.Peer
  46         var terminator chan struct{}
  47 MainCycle:
  48         for {
  49                 select {
  50                 case <-termination:
  51                         break MainCycle
  52                 default:
  53                 }
  54
  55                 conn.SetReadDeadline(time.Now().Add(time.Second))
  56                 n, err = conn.Read(buf)
  57                 if timeouts == timeout {
  58                         log.Println("Timeouted")
  59                         timeouted <- struct{}{}
  60                         break
  61                 }
  62                 if err != nil {
  63                         timeouts++
  64                         continue
  65                 }
  66                 if peer != nil {
  67                         if peer.PktProcess(buf[:n], tap, true) {
  68                                 timeouts = 0
  69                         } else {
  70                                 log.Println("Unauthenticated packet")
  71                                 timeouts++
  72                         }
  73                         if atomic.LoadInt64(&peer.BytesIn)+atomic.LoadInt64(&peer.BytesOut) > govpn.MaxBytesPerKey {
  74                                 log.Println("Need rehandshake")
  75                                 terminator <- struct{}{}
  76                                 terminator = nil
  77                                 rehandshaking <- struct{}{}
  78                                 break MainCycle
  79                         }
  80                         continue
  81                 }
  82                 if govpn.IDsCache.Find(buf[:n]) == nil {
  83                         log.Println("Invalid identity in handshake packet")
  84                         continue
  85                 }
  86                 timeouts = 0
  87                 peer = hs.Client(buf[:n])
  88                 if peer == nil {
  89                         continue
  90                 }
  91                 log.Println("Handshake completed")
  92                 knownPeers = govpn.KnownPeers(map[string]**govpn.Peer{*remoteAddr: &peer})
  93                 if firstUpCall {
  94                         go govpn.ScriptCall(*upPath, *ifaceName)
  95                         firstUpCall = false
  96                 }
  97                 hs.Zero()
  98                 terminator = make(chan struct{})
  99                 go func() {
 100                         heartbeat := time.NewTicker(peer.Timeout)
 101                         var data []byte
 102                 Processor:
 103                         for {
 104                                 select {
 105                                 case <-heartbeat.C:
 106                                         peer.EthProcess(nil)
 107                                 case <-terminator:
 108                                         break Processor
 109                                 case data = <-tap.Sink:
 110                                         peer.EthProcess(data)
 111                                 }
 112                         }
 113                         heartbeat.Stop()
 114                         peer.Zero()
 115                 }()
 116         }
 117         if terminator != nil {
 118                 terminator <- struct{}{}
 119         }
 120         if hs != nil {
 121                 hs.Zero()
 122         }
 123 }