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