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         "time"
  29
  30         "govpn"
  31 )
  32
  33 var (
  34         remoteAddr = flag.String("remote", "", "Remote server address")
  35         ifaceName  = flag.String("iface", "tap0", "TAP network interface")
  36         IDRaw      = flag.String("id", "", "Client identification")
  37         keyPath    = flag.String("key", "", "Path to authentication key file")
  38         upPath     = flag.String("up", "", "Path to up-script")
  39         downPath   = flag.String("down", "", "Path to down-script")
  40         stats      = flag.String("stats", "", "Enable stats retrieving on host:port")
  41         mtu        = flag.Int("mtu", 1452, "MTU for outgoing packets")
  42         nonceDiff  = flag.Int("noncediff", 1, "Allow nonce difference")
  43         timeoutP   = flag.Int("timeout", 60, "Timeout seconds")
  44         noisy      = flag.Bool("noise", false, "Enable noise appending")
  45         cpr        = flag.Int("cpr", 0, "Enable constant KiB/s out traffic rate")
  46 )
  47
  48 func main() {
  49         flag.Parse()
  50         timeout := *timeoutP
  51         var err error
  52         log.SetFlags(log.Ldate | log.Lmicroseconds | log.Lshortfile)
  53
  54         govpn.MTU = *mtu
  55         govpn.Timeout = time.Second * time.Duration(timeout)
  56         govpn.Noncediff = *nonceDiff
  57         govpn.NoiseEnable = *noisy
  58         govpn.CPRInit(*cpr)
  59
  60         id := govpn.IDDecode(*IDRaw)
  61         govpn.PeersInitDummy(id)
  62         key := govpn.KeyRead(*keyPath)
  63         if id == nil {
  64                 panic("ID is not specified")
  65         }
  66
  67         bind, err := net.ResolveUDPAddr("udp", "0.0.0.0:0")
  68         if err != nil {
  69                 panic(err)
  70         }
  71         conn, err := net.ListenUDP("udp", bind)
  72         if err != nil {
  73                 panic(err)
  74         }
  75         remote, err := net.ResolveUDPAddr("udp", *remoteAddr)
  76         if err != nil {
  77                 panic(err)
  78         }
  79
  80         tap, ethSink, ethReady, _, err := govpn.TAPListen(*ifaceName)
  81         if err != nil {
  82                 panic(err)
  83         }
  84         udpSink, udpBuf, udpReady := govpn.ConnListen(conn)
  85
  86         timeouts := 0
  87         firstUpCall := true
  88         var peer *govpn.Peer
  89         var ethPkt []byte
  90         var udpPkt govpn.UDPPkt
  91         var udpPktData []byte
  92         knownPeers := govpn.KnownPeers(map[string]**govpn.Peer{remote.String(): &peer})
  93
  94         log.Println(govpn.VersionGet())
  95         log.Println("Max MTU on TAP interface:", govpn.TAPMaxMTU())
  96         if *stats != "" {
  97                 log.Println("Stats are going to listen on", *stats)
  98                 statsPort, err := net.Listen("tcp", *stats)
  99                 if err != nil {
 100                         panic(err)
 101                 }
 102                 go govpn.StatsProcessor(statsPort, &knownPeers)
 103         }
 104
 105         termSignal := make(chan os.Signal, 1)
 106         signal.Notify(termSignal, os.Interrupt, os.Kill)
 107
 108         log.Println("Starting handshake")
 109         handshake := govpn.HandshakeStart(conn, remote, id, key)
 110
 111 MainCycle:
 112         for {
 113                 if peer != nil && (peer.BytesIn+peer.BytesOut) > govpn.MaxBytesPerKey {
 114                         peer.Zero()
 115                         peer = nil
 116                         handshake = govpn.HandshakeStart(conn, remote, id, key)
 117                         log.Println("Rehandshaking")
 118                 }
 119                 select {
 120                 case <-termSignal:
 121                         break MainCycle
 122                 case ethPkt = <-ethSink:
 123                         if peer == nil {
 124                                 if len(ethPkt) > 0 {
 125                                         ethReady <- struct{}{}
 126                                 }
 127                                 continue
 128                         }
 129                         peer.EthProcess(ethPkt, conn, ethReady)
 130                 case udpPkt = <-udpSink:
 131                         timeouts++
 132                         if timeouts >= timeout {
 133                                 break MainCycle
 134                         }
 135                         if udpPkt.Addr == nil {
 136                                 udpReady <- struct{}{}
 137                                 continue
 138                         }
 139
 140                         udpPktData = udpBuf[:udpPkt.Size]
 141                         if peer == nil {
 142                                 if udpPkt.Addr.String() != remote.String() {
 143                                         udpReady <- struct{}{}
 144                                         log.Println("Unknown handshake message")
 145                                         continue
 146                                 }
 147                                 if govpn.IDsCache.Find(udpPktData) == nil {
 148                                         log.Println("Invalid identity in handshake packet")
 149                                         udpReady <- struct{}{}
 150                                         continue
 151                                 }
 152                                 if p := handshake.Client(id, conn, key, udpPktData); p != nil {
 153                                         log.Println("Handshake completed")
 154                                         if firstUpCall {
 155                                                 go govpn.ScriptCall(*upPath, *ifaceName)
 156                                                 firstUpCall = false
 157                                         }
 158                                         peer = p
 159                                         handshake.Zero()
 160                                         handshake = nil
 161                                 }
 162                                 udpReady <- struct{}{}
 163                                 continue
 164                         }
 165                         if peer == nil {
 166                                 udpReady <- struct{}{}
 167                                 continue
 168                         }
 169                         if peer.UDPProcess(udpPktData, tap, udpReady) {
 170                                 timeouts = 0
 171                         }
 172                 }
 173         }
 174         govpn.ScriptCall(*downPath, *ifaceName)
 175 }