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         key := govpn.KeyRead(*keyPath)
  56         if id == nil {
  57                 panic("ID is not specified")
  58         }
  59
  60         bind, err := net.ResolveUDPAddr("udp", "0.0.0.0:0")
  61         if err != nil {
  62                 panic(err)
  63         }
  64         conn, err := net.ListenUDP("udp", bind)
  65         if err != nil {
  66                 panic(err)
  67         }
  68         remote, err := net.ResolveUDPAddr("udp", *remoteAddr)
  69         if err != nil {
  70                 panic(err)
  71         }
  72
  73         tap, ethSink, ethReady, _, err := govpn.TAPListen(*ifaceName)
  74         if err != nil {
  75                 panic(err)
  76         }
  77         udpSink, udpBuf, udpReady := govpn.ConnListen(conn)
  78
  79         timeouts := 0
  80         firstUpCall := true
  81         var peer *govpn.Peer
  82         var ethPkt []byte
  83         var udpPkt *govpn.UDPPkt
  84         var udpPktData []byte
  85
  86         termSignal := make(chan os.Signal, 1)
  87         signal.Notify(termSignal, os.Interrupt, os.Kill)
  88
  89         log.Println("Client version", govpn.Version)
  90         log.Println("Starting handshake")
  91         handshake := govpn.HandshakeStart(conn, remote, id, key)
  92
  93 MainCycle:
  94         for {
  95                 if peer != nil && peer.Bytes > govpn.MaxBytesPerKey {
  96                         peer = nil
  97                         handshake = govpn.HandshakeStart(conn, remote, id, key)
  98                         log.Println("Rehandshaking")
  99                 }
 100                 select {
 101                 case <-termSignal:
 102                         break MainCycle
 103                 case ethPkt = <-ethSink:
 104                         if peer == nil {
 105                                 if len(ethPkt) > 0 {
 106                                         ethReady <- struct{}{}
 107                                 }
 108                                 continue
 109                         }
 110                         peer.EthProcess(ethPkt, conn, ethReady)
 111                 case udpPkt = <-udpSink:
 112                         timeouts++
 113                         if timeouts >= timeout {
 114                                 break MainCycle
 115                         }
 116                         if udpPkt == nil {
 117                                 udpReady <- struct{}{}
 118                                 continue
 119                         }
 120
 121                         udpPktData = udpBuf[:udpPkt.Size]
 122                         if govpn.IsValidHandshakePkt(udpPktData) {
 123                                 if udpPkt.Addr.String() != remote.String() {
 124                                         udpReady <- struct{}{}
 125                                         log.Println("Unknown handshake message")
 126                                         continue
 127                                 }
 128                                 if p := handshake.Client(conn, key, udpPktData); p != nil {
 129                                         log.Println("Handshake completed")
 130                                         if firstUpCall {
 131                                                 go govpn.ScriptCall(*upPath, *ifaceName)
 132                                                 firstUpCall = false
 133                                         }
 134                                         peer = p
 135                                         handshake = nil
 136                                 }
 137                                 udpReady <- struct{}{}
 138                                 continue
 139                         }
 140                         if peer == nil {
 141                                 udpReady <- struct{}{}
 142                                 continue
 143                         }
 144                         if peer.UDPProcess(udpPktData, tap, udpReady) {
 145                                 timeouts = 0
 146                         }
 147                 }
 148         }
 149         govpn.ScriptCall(*downPath, *ifaceName)
 150 }