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

   1 /*
   2 GoVPN -- simple secure free software virtual private network daemon
   3 Copyright (C) 2014-2016 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         "net"
  23         "sync/atomic"
  24         "time"
  25
  26         "github.com/pkg/errors"
  27
  28         "cypherpunks.ru/govpn"
  29 )
  30
  31 func (c *Client) startUDP() {
  32         l := c.logger.WithField("func", "startUDP")
  33
  34         // TODO move resolution into the loop, as the name might change over time
  35         l.Debug("Resolve UDP address")
  36         remote, err := net.ResolveUDPAddr("udp", c.config.RemoteAddress)
  37         if err != nil {
  38                 c.Error <- errors.Wrapf(err, "net.ResolveUDPAddr %s", c.config.RemoteAddress)
  39                 return
  40         }
  41         l.WithField("remote", remote.String()).Debug("dial")
  42         conn, err := net.DialUDP("udp", nil, remote)
  43         if err != nil {
  44                 c.Error <- errors.Wrapf(err, "net.DialUDP %s", c.config.RemoteAddress)
  45                 return
  46         }
  47         l.WithFields(c.config.LogFields()).Info("Connected")
  48
  49         l.Debug("Handshake start")
  50         hs, err := govpn.HandshakeStart(c.config.RemoteAddress, conn, c.config.Peer)
  51         if err != nil {
  52                 govpn.CloseLog(conn, c.logger, c.LogFields())
  53                 c.Error <- errors.Wrap(err, "govpn.HandshakeStart")
  54                 return
  55         }
  56         l.Debug("Handshake done")
  57
  58         buf := make([]byte, c.config.Peer.MTU*2)
  59         var n int
  60         var timeouts int
  61         var peer *govpn.Peer
  62         var deadLine time.Time
  63         var terminator chan struct{}
  64         timeout := int(c.config.Peer.Timeout.Seconds())
  65         l.Debug("Main cycle")
  66
  67 MainCycle:
  68         for {
  69                 select {
  70                 case <-c.termination:
  71                         break MainCycle
  72                 default:
  73                 }
  74
  75                 deadLine = time.Now().Add(time.Second)
  76                 if err = conn.SetReadDeadline(deadLine); err != nil {
  77                         c.Error <- errors.Wrapf(err, "conn.SetReadDeadline %s", deadLine.String())
  78                         break MainCycle
  79                 }
  80                 l.Debug("conn.Read")
  81                 n, err = conn.Read(buf)
  82                 if timeouts >= timeout {
  83                         l.WithFields(c.LogFields()).Debug("Connection timeouted")
  84                         c.timeouted <- struct{}{}
  85                         break
  86                 }
  87                 if err != nil {
  88                         l.WithError(err).WithFields(c.LogFields()).Debug("Can't read from connection")
  89                         timeouts++
  90                         continue
  91                 }
  92                 if peer != nil {
  93                         c.logger.WithFields(c.LogFields()).Debug("No peer yet, process packet")
  94                         if peer.PktProcess(buf[:n], c.tap, true) {
  95                                 l.WithFields(c.LogFields()).Debug("Packet processed")
  96                                 timeouts = 0
  97                         } else {
  98                                 l.WithFields(c.LogFields()).Debug("Packet unauthenticated")
  99                                 timeouts++
 100                         }
 101                         if atomic.LoadUint64(&peer.BytesIn)+atomic.LoadUint64(&peer.BytesOut) > govpn.MaxBytesPerKey {
 102                                 l.WithFields(c.LogFields()).Debug("Rehandshake required")
 103                                 c.rehandshaking <- struct{}{}
 104                                 break MainCycle
 105                         }
 106                         continue
 107                 }
 108                 if _, err = c.idsCache.Find(buf[:n]); err != nil {
 109                         l.WithError(err).WithFields(c.LogFields()).Debug("Identity invalid")
 110                         continue
 111                 }
 112                 timeouts = 0
 113                 peer, err = hs.Client(buf[:n])
 114                 if err != nil {
 115                         c.Error <- errors.Wrap(err, "hs.Client")
 116                         continue
 117                 }
 118                 // no error, but handshake not yet completed
 119                 if peer == nil {
 120                         continue
 121                 }
 122                 l.WithFields(c.LogFields()).Info("Handshake completed")
 123                 c.knownPeers = govpn.KnownPeers(map[string]**govpn.Peer{c.config.RemoteAddress: &peer})
 124                 if err = c.postUpAction(); err != nil {
 125                         c.Error <- errors.Wrap(err, "c.postUpAction")
 126                         continue
 127                 }
 128                 hs.Zero()
 129                 terminator = make(chan struct{})
 130                 go govpn.PeerTapProcessor(peer, c.tap, terminator)
 131         }
 132         if terminator != nil {
 133                 terminator <- struct{}{}
 134         }
 135         if hs != nil {
 136                 hs.Zero()
 137         }
 138         if err = conn.Close(); err != nil {
 139                 c.Error <- errors.Wrap(err, "conn.Close")
 140         }
 141         if err = c.tap.Close(); err != nil {
 142                 c.Error <- errors.Wrap(err, logFuncPrefix+"Client.tap.Close")
 143         }
 144 }