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