src/cypherpunks.ru/govpn/client/udp.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         "fmt"
  23         "net"
  24         "sync/atomic"
  25         "time"
  26
  27         "cypherpunks.ru/govpn"
  28 )
  29
  30 func (c *Client) startUDP() {
  31         remote, err := net.ResolveUDPAddr("udp", c.config.RemoteAddress)
  32         if err != nil {
  33                 c.Error <- fmt.Errorf("Can not resolve remote address: %s", err)
  34                 return
  35         }
  36         conn, err := net.DialUDP("udp", nil, remote)
  37         if err != nil {
  38                 c.Error <- fmt.Errorf("Can not connect remote address: %s", err)
  39                 return
  40         }
  41         govpn.Printf(`[connected remote="%s"]`, c.config.RemoteAddress)
  42
  43         hs := govpn.HandshakeStart(c.config.RemoteAddress, conn, c.config.Peer)
  44         buf := make([]byte, c.config.MTU*2)
  45         var n int
  46         var timeouts int
  47         var peer *govpn.Peer
  48         var terminator chan struct{}
  49         timeout := int(c.config.Peer.Timeout.Seconds())
  50 MainCycle:
  51         for {
  52                 select {
  53                 case <-c.termination:
  54                         break MainCycle
  55                 default:
  56                 }
  57
  58                 if err = conn.SetReadDeadline(time.Now().Add(time.Second)); err != nil {
  59                         c.Error <- err
  60                         break MainCycle
  61                 }
  62                 n, err = conn.Read(buf)
  63                 if timeouts == timeout {
  64                         govpn.Printf(`[connection-timeouted remote="%s"]`, c.config.RemoteAddress)
  65                         c.timeouted <- struct{}{}
  66                         break
  67                 }
  68                 if err != nil {
  69                         timeouts++
  70                         continue
  71                 }
  72                 if peer != nil {
  73                         if peer.PktProcess(buf[:n], c.tap, true) {
  74                                 timeouts = 0
  75                         } else {
  76                                 govpn.Printf(`[packet-unauthenticated remote="%s"]`, c.config.RemoteAddress)
  77                                 timeouts++
  78                         }
  79                         if atomic.LoadUint64(&peer.BytesIn)+atomic.LoadUint64(&peer.BytesOut) > govpn.MaxBytesPerKey {
  80                                 govpn.Printf(`[rehandshake-required remote="%s"]`, c.config.RemoteAddress)
  81                                 c.rehandshaking <- struct{}{}
  82                                 break MainCycle
  83                         }
  84                         continue
  85                 }
  86                 if c.idsCache.Find(buf[:n]) == nil {
  87                         govpn.Printf(`[identity-invalid remote="%s"]`, c.config.RemoteAddress)
  88                         continue
  89                 }
  90                 timeouts = 0
  91                 peer = hs.Client(buf[:n])
  92                 if peer == nil {
  93                         continue
  94                 }
  95                 govpn.Printf(`[handshake-completed remote="%s"]`, c.config.RemoteAddress)
  96                 c.knownPeers.Store(c.config.RemoteAddress, &peer)
  97                 if c.firstUpCall {
  98                         go govpn.ScriptCall(c.config.UpPath, c.config.InterfaceName, c.config.RemoteAddress)
  99                         c.firstUpCall = false
 100                 }
 101                 hs.Zero()
 102                 terminator = make(chan struct{})
 103                 go govpn.PeerTapProcessor(peer, c.tap, terminator)
 104         }
 105         if terminator != nil {
 106                 terminator <- struct{}{}
 107         }
 108         if hs != nil {
 109                 hs.Zero()
 110         }
 111         if err = conn.Close(); err != nil {
 112                 c.Error <- err
 113         }
 114 }