cmd/govpn-client/main.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 // Simple secure free software virtual private network daemon.
  20 package main
  21
  22 import (
  23         "flag"
  24         "log"
  25         "net"
  26         "os"
  27         "os/signal"
  28
  29         "govpn"
  30 )
  31
  32 var (
  33         remoteAddr = flag.String("remote", "", "Remote server address")
  34         ifaceName  = flag.String("iface", "tap0", "TAP network interface")
  35         IDRaw      = flag.String("id", "", "Client identification")
  36         keyPath    = flag.String("key", "", "Path to authentication key file")
  37         upPath     = flag.String("up", "", "Path to up-script")
  38         downPath   = flag.String("down", "", "Path to down-script")
  39         stats      = flag.String("stats", "", "Enable stats retrieving on host:port")
  40         mtu        = flag.Int("mtu", 1452, "MTU for outgoing packets")
  41         nonceDiff  = flag.Int("noncediff", 1, "Allow nonce difference")
  42         timeoutP   = flag.Int("timeout", 60, "Timeout seconds")
  43         noisy      = flag.Bool("noise", false, "Enable noise appending")
  44 )
  45
  46 func main() {
  47         flag.Parse()
  48         timeout := *timeoutP
  49         var err error
  50         log.SetFlags(log.Ldate | log.Lmicroseconds | log.Lshortfile)
  51
  52         govpn.MTU = *mtu
  53         govpn.Timeout = timeout
  54         govpn.Noncediff = *nonceDiff
  55         govpn.NoiseEnable = *noisy
  56
  57         id := govpn.IDDecode(*IDRaw)
  58         govpn.PeersInitDummy(id)
  59         key := govpn.KeyRead(*keyPath)
  60         if id == nil {
  61                 panic("ID is not specified")
  62         }
  63
  64         bind, err := net.ResolveUDPAddr("udp", "0.0.0.0:0")
  65         if err != nil {
  66                 panic(err)
  67         }
  68         conn, err := net.ListenUDP("udp", bind)
  69         if err != nil {
  70                 panic(err)
  71         }
  72         remote, err := net.ResolveUDPAddr("udp", *remoteAddr)
  73         if err != nil {
  74                 panic(err)
  75         }
  76
  77         tap, ethSink, ethReady, _, err := govpn.TAPListen(*ifaceName)
  78         if err != nil {
  79                 panic(err)
  80         }
  81         udpSink, udpBuf, udpReady := govpn.ConnListen(conn)
  82
  83         timeouts := 0
  84         firstUpCall := true
  85         var peer *govpn.Peer
  86         var ethPkt []byte
  87         var udpPkt govpn.UDPPkt
  88         var udpPktData []byte
  89         knownPeers := govpn.KnownPeers(map[string]**govpn.Peer{remote.String(): &peer})
  90
  91         log.Println(govpn.VersionGet())
  92         log.Println("Max MTU on TAP interface:", govpn.TAPMaxMTU())
  93         if *stats != "" {
  94                 log.Println("Stats are going to listen on", *stats)
  95                 statsPort, err := net.Listen("tcp", *stats)
  96                 if err != nil {
  97                         panic(err)
  98                 }
  99                 go govpn.StatsProcessor(statsPort, &knownPeers)
 100         }
 101
 102         termSignal := make(chan os.Signal, 1)
 103         signal.Notify(termSignal, os.Interrupt, os.Kill)
 104
 105         log.Println("Starting handshake")
 106         handshake := govpn.HandshakeStart(conn, remote, id, key)
 107
 108 MainCycle:
 109         for {
 110                 if peer != nil && (peer.BytesIn+peer.BytesOut) > govpn.MaxBytesPerKey {
 111                         peer.Zero()
 112                         peer = nil
 113                         handshake = govpn.HandshakeStart(conn, remote, id, key)
 114                         log.Println("Rehandshaking")
 115                 }
 116                 select {
 117                 case <-termSignal:
 118                         break MainCycle
 119                 case ethPkt = <-ethSink:
 120                         if peer == nil {
 121                                 if len(ethPkt) > 0 {
 122                                         ethReady <- struct{}{}
 123                                 }
 124                                 continue
 125                         }
 126                         peer.EthProcess(ethPkt, conn, ethReady)
 127                 case udpPkt = <-udpSink:
 128                         timeouts++
 129                         if timeouts >= timeout {
 130                                 break MainCycle
 131                         }
 132                         if udpPkt.Addr == nil {
 133                                 udpReady <- struct{}{}
 134                                 continue
 135                         }
 136
 137                         udpPktData = udpBuf[:udpPkt.Size]
 138                         if peer == nil {
 139                                 if udpPkt.Addr.String() != remote.String() {
 140                                         udpReady <- struct{}{}
 141                                         log.Println("Unknown handshake message")
 142                                         continue
 143                                 }
 144                                 if govpn.IDsCache.Find(udpPktData) == nil {
 145                                         log.Println("Invalid identity in handshake packet")
 146                                         udpReady <- struct{}{}
 147                                         continue
 148                                 }
 149                                 if p := handshake.Client(id, conn, key, udpPktData); p != nil {
 150                                         log.Println("Handshake completed")
 151                                         if firstUpCall {
 152                                                 go govpn.ScriptCall(*upPath, *ifaceName)
 153                                                 firstUpCall = false
 154                                         }
 155                                         peer = p
 156                                         handshake.Zero()
 157                                         handshake = nil
 158                                 }
 159                                 udpReady <- struct{}{}
 160                                 continue
 161                         }
 162                         if peer == nil {
 163                                 udpReady <- struct{}{}
 164                                 continue
 165                         }
 166                         if peer.UDPProcess(udpPktData, tap, udpReady) {
 167                                 timeouts = 0
 168                         }
 169                 }
 170         }
 171         govpn.ScriptCall(*downPath, *ifaceName)
 172 }