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