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         mtu        = flag.Int("mtu", 1500, "MTU")
  40         nonceDiff  = flag.Int("noncediff", 1, "Allow nonce difference")
  41         timeoutP   = flag.Int("timeout", 60, "Timeout seconds")
  42 )
  43
  44 func main() {
  45         flag.Parse()
  46         timeout := *timeoutP
  47         var err error
  48         log.SetFlags(log.Ldate | log.Lmicroseconds | log.Lshortfile)
  49
  50         govpn.MTU = *mtu
  51         govpn.Timeout = timeout
  52         govpn.Noncediff = *nonceDiff
  53
  54         id := govpn.IDDecode(*IDRaw)
  55         govpn.PeersInitDummy(id)
  56         key := govpn.KeyRead(*keyPath)
  57         if id == nil {
  58                 panic("ID is not specified")
  59         }
  60
  61         bind, err := net.ResolveUDPAddr("udp", "0.0.0.0:0")
  62         if err != nil {
  63                 panic(err)
  64         }
  65         conn, err := net.ListenUDP("udp", bind)
  66         if err != nil {
  67                 panic(err)
  68         }
  69         remote, err := net.ResolveUDPAddr("udp", *remoteAddr)
  70         if err != nil {
  71                 panic(err)
  72         }
  73
  74         tap, ethSink, ethReady, _, err := govpn.TAPListen(*ifaceName)
  75         if err != nil {
  76                 panic(err)
  77         }
  78         udpSink, udpBuf, udpReady := govpn.ConnListen(conn)
  79
  80         timeouts := 0
  81         firstUpCall := true
  82         var peer *govpn.Peer
  83         var ethPkt []byte
  84         var udpPkt *govpn.UDPPkt
  85         var udpPktData []byte
  86
  87         termSignal := make(chan os.Signal, 1)
  88         signal.Notify(termSignal, os.Interrupt, os.Kill)
  89
  90         log.Println(govpn.VersionGet())
  91         log.Println("Starting handshake")
  92         handshake := govpn.HandshakeStart(conn, remote, id, key)
  93
  94 MainCycle:
  95         for {
  96                 if peer != nil && peer.Bytes > govpn.MaxBytesPerKey {
  97                         peer.Zero()
  98                         peer = nil
  99                         handshake = govpn.HandshakeStart(conn, remote, id, key)
 100                         log.Println("Rehandshaking")
 101                 }
 102                 select {
 103                 case <-termSignal:
 104                         break MainCycle
 105                 case ethPkt = <-ethSink:
 106                         if peer == nil {
 107                                 if len(ethPkt) > 0 {
 108                                         ethReady <- struct{}{}
 109                                 }
 110                                 continue
 111                         }
 112                         peer.EthProcess(ethPkt, conn, ethReady)
 113                 case udpPkt = <-udpSink:
 114                         timeouts++
 115                         if timeouts >= timeout {
 116                                 break MainCycle
 117                         }
 118                         if udpPkt == nil {
 119                                 udpReady <- struct{}{}
 120                                 continue
 121                         }
 122
 123                         udpPktData = udpBuf[:udpPkt.Size]
 124                         if peer == nil {
 125                                 if udpPkt.Addr.String() != remote.String() {
 126                                         udpReady <- struct{}{}
 127                                         log.Println("Unknown handshake message")
 128                                         continue
 129                                 }
 130                                 if govpn.IDsCache.Find(udpPktData) == nil {
 131                                         log.Println("Invalid identity in handshake packet")
 132                                         udpReady <- struct{}{}
 133                                         continue
 134                                 }
 135                                 if p := handshake.Client(id, conn, key, udpPktData); p != nil {
 136                                         log.Println("Handshake completed")
 137                                         if firstUpCall {
 138                                                 go govpn.ScriptCall(*upPath, *ifaceName)
 139                                                 firstUpCall = false
 140                                         }
 141                                         peer = p
 142                                         handshake.Zero()
 143                                         handshake = nil
 144                                 }
 145                                 udpReady <- struct{}{}
 146                                 continue
 147                         }
 148                         if peer == nil {
 149                                 udpReady <- struct{}{}
 150                                 continue
 151                         }
 152                         if peer.UDPProcess(udpPktData, tap, udpReady) {
 153                                 timeouts = 0
 154                         }
 155                 }
 156         }
 157         govpn.ScriptCall(*downPath, *ifaceName)
 158 }