src/govpn/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 client.
  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 passphrase 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/sec out traffic rate")
  46         egdPath    = flag.String("egd", "", "Optional path to EGD socket")
  47 )
  48
  49 func main() {
  50         flag.Parse()
  51         timeout := *timeoutP
  52         var err error
  53         log.SetFlags(log.Ldate | log.Lmicroseconds | log.Lshortfile)
  54
  55         govpn.MTU = *mtu
  56
  57         id, err := govpn.IDDecode(*IDRaw)
  58         if err != nil {
  59                 log.Fatalln(err)
  60         }
  61
  62         if *egdPath != "" {
  63                 log.Println("Using", *egdPath, "EGD")
  64                 govpn.EGDInit(*egdPath)
  65         }
  66
  67         pub, priv := govpn.NewVerifier(id, govpn.StringFromFile(*keyPath))
  68         conf := &govpn.PeerConf{
  69                 Id:          id,
  70                 Timeout:     time.Second * time.Duration(timeout),
  71                 Noncediff:   *nonceDiff,
  72                 NoiseEnable: *noisy,
  73                 CPR:         *cpr,
  74                 DSAPub:      pub,
  75                 DSAPriv:     priv,
  76         }
  77         govpn.PeersInitDummy(id, conf)
  78
  79         bind, err := net.ResolveUDPAddr("udp", "0.0.0.0:0")
  80         if err != nil {
  81                 log.Fatalln("Can not resolve address:", err)
  82         }
  83         conn, err := net.ListenUDP("udp", bind)
  84         if err != nil {
  85                 log.Fatalln("Can not listen on UDP:", err)
  86         }
  87         remote, err := net.ResolveUDPAddr("udp", *remoteAddr)
  88         if err != nil {
  89                 log.Fatalln("Can not resolve remote address:", err)
  90         }
  91
  92         tap, ethSink, ethReady, _, err := govpn.TAPListen(
  93                 *ifaceName,
  94                 time.Second*time.Duration(timeout),
  95                 *cpr,
  96         )
  97         if err != nil {
  98                 log.Fatalln("Can not listen on TAP interface:", err)
  99         }
 100         udpSink, udpBuf, udpReady := govpn.ConnListen(conn)
 101
 102         timeouts := 0
 103         firstUpCall := true
 104         var peer *govpn.Peer
 105         var ethPkt []byte
 106         var udpPkt govpn.UDPPkt
 107         var udpPktData []byte
 108         knownPeers := govpn.KnownPeers(map[string]**govpn.Peer{remote.String(): &peer})
 109
 110         log.Println(govpn.VersionGet())
 111         log.Println("Max MTU on TAP interface:", govpn.TAPMaxMTU())
 112         if *stats != "" {
 113                 log.Println("Stats are going to listen on", *stats)
 114                 statsPort, err := net.Listen("tcp", *stats)
 115                 if err != nil {
 116                         log.Fatalln("Can not listen on stats port:", err)
 117                 }
 118                 go govpn.StatsProcessor(statsPort, &knownPeers)
 119         }
 120
 121         termSignal := make(chan os.Signal, 1)
 122         signal.Notify(termSignal, os.Interrupt, os.Kill)
 123
 124         log.Println("Starting handshake")
 125         handshake := govpn.HandshakeStart(conf, conn, remote)
 126
 127 MainCycle:
 128         for {
 129                 if peer != nil && (peer.BytesIn+peer.BytesOut) > govpn.MaxBytesPerKey {
 130                         peer.Zero()
 131                         peer = nil
 132                         handshake = govpn.HandshakeStart(conf, conn, remote)
 133                         log.Println("Rehandshaking")
 134                 }
 135                 select {
 136                 case <-termSignal:
 137                         break MainCycle
 138                 case ethPkt = <-ethSink:
 139                         if peer == nil {
 140                                 if len(ethPkt) > 0 {
 141                                         ethReady <- struct{}{}
 142                                 }
 143                                 continue
 144                         }
 145                         peer.EthProcess(ethPkt, conn, ethReady)
 146                 case udpPkt = <-udpSink:
 147                         timeouts++
 148                         if timeouts >= timeout {
 149                                 break MainCycle
 150                         }
 151                         if udpPkt.Addr == nil {
 152                                 udpReady <- struct{}{}
 153                                 continue
 154                         }
 155
 156                         udpPktData = udpBuf[:udpPkt.Size]
 157                         if peer == nil {
 158                                 if udpPkt.Addr.String() != remote.String() {
 159                                         udpReady <- struct{}{}
 160                                         log.Println("Unknown handshake message")
 161                                         continue
 162                                 }
 163                                 if govpn.IDsCache.Find(udpPktData) == nil {
 164                                         log.Println("Invalid identity in handshake packet")
 165                                         udpReady <- struct{}{}
 166                                         continue
 167                                 }
 168                                 if p := handshake.Client(conn, udpPktData); p != nil {
 169                                         log.Println("Handshake completed")
 170                                         if firstUpCall {
 171                                                 go govpn.ScriptCall(*upPath, *ifaceName)
 172                                                 firstUpCall = false
 173                                         }
 174                                         peer = p
 175                                         handshake.Zero()
 176                                         handshake = nil
 177                                 }
 178                                 udpReady <- struct{}{}
 179                                 continue
 180                         }
 181                         if peer == nil {
 182                                 udpReady <- struct{}{}
 183                                 continue
 184                         }
 185                         if peer.UDPProcess(udpPktData, tap, udpReady) {
 186                                 timeouts = 0
 187                         }
 188                 }
 189         }
 190         govpn.ScriptCall(*downPath, *ifaceName)
 191 }