src/govpn/cmd/govpn-server/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         "bytes"
  24         "flag"
  25         "io"
  26         "log"
  27         "net"
  28         "os"
  29         "os/signal"
  30         "path"
  31         "time"
  32
  33         "govpn"
  34 )
  35
  36 var (
  37         bindAddr  = flag.String("bind", "[::]:1194", "Bind to address")
  38         peersPath = flag.String("peers", "peers", "Path to peers keys directory")
  39         stats     = flag.String("stats", "", "Enable stats retrieving on host:port")
  40         mtu       = flag.Int("mtu", 1452, "MTU for outgoing packets")
  41         egdPath   = flag.String("egd", "", "Optional path to EGD socket")
  42 )
  43
  44 type Pkt struct {
  45         addr string
  46         conn io.Writer
  47         data []byte
  48 }
  49
  50 type UDPSender struct {
  51         conn *net.UDPConn
  52         addr *net.UDPAddr
  53 }
  54
  55 func (c UDPSender) Write(data []byte) (int, error) {
  56         return c.conn.WriteToUDP(data, c.addr)
  57 }
  58
  59 type PeerReadyEvent struct {
  60         peer  *govpn.Peer
  61         iface string
  62 }
  63
  64 type PeerState struct {
  65         peer      *govpn.Peer
  66         tap       *govpn.TAP
  67         sink      chan []byte
  68         ready     chan struct{}
  69         terminate chan struct{}
  70 }
  71
  72 func NewPeerState(peer *govpn.Peer, iface string) *PeerState {
  73         tap, sink, ready, terminate, err := govpn.TAPListen(iface, peer.Timeout, peer.CPR)
  74         if err != nil {
  75                 log.Println("Unable to create Eth", err)
  76                 return nil
  77         }
  78         state := PeerState{
  79                 peer:      peer,
  80                 tap:       tap,
  81                 sink:      sink,
  82                 ready:     ready,
  83                 terminate: terminate,
  84         }
  85         return &state
  86 }
  87
  88 type EthEvent struct {
  89         peer  *govpn.Peer
  90         data  []byte
  91         ready chan struct{}
  92 }
  93
  94 func main() {
  95         flag.Parse()
  96         timeout := time.Second * time.Duration(govpn.TimeoutDefault)
  97         var err error
  98         log.SetFlags(log.Ldate | log.Lmicroseconds | log.Lshortfile)
  99
 100         govpn.MTU = *mtu
 101         govpn.PeersInit(*peersPath)
 102
 103         if *egdPath != "" {
 104                 log.Println("Using", *egdPath, "EGD")
 105                 govpn.EGDInit(*egdPath)
 106         }
 107
 108         bind, err := net.ResolveUDPAddr("udp", *bindAddr)
 109         if err != nil {
 110                 log.Fatalln("Can not resolve bind address:", err)
 111         }
 112         lconn, err := net.ListenUDP("udp", bind)
 113         if err != nil {
 114                 log.Fatalln("Can listen on UDP:", err)
 115         }
 116
 117         sink := make(chan Pkt)
 118         ready := make(chan struct{})
 119         go func() {
 120                 buf := make([]byte, govpn.MTU)
 121                 var n int
 122                 var raddr *net.UDPAddr
 123                 var err error
 124                 for {
 125                         <-ready
 126                         lconn.SetReadDeadline(time.Now().Add(time.Second))
 127                         n, raddr, err = lconn.ReadFromUDP(buf)
 128                         if err != nil {
 129                                 // This is needed for ticking the timeouts counter outside
 130                                 sink <- Pkt{}
 131                                 continue
 132                         }
 133                         sink <- Pkt{raddr.String(), UDPSender{lconn, raddr}, buf[:n]}
 134                 }
 135         }()
 136         ready <- struct{}{}
 137
 138         termSignal := make(chan os.Signal, 1)
 139         signal.Notify(termSignal, os.Interrupt, os.Kill)
 140
 141         hsHeartbeat := time.Tick(timeout)
 142         go func() { <-hsHeartbeat }()
 143
 144         var state *govpn.Handshake
 145         var peerState *PeerState
 146         var peer *govpn.Peer
 147         var exists bool
 148         states := make(map[string]*govpn.Handshake)
 149         peers := make(map[string]*PeerState)
 150         peerReadySink := make(chan PeerReadyEvent)
 151         knownPeers := govpn.KnownPeers(make(map[string]**govpn.Peer))
 152         var peerReady PeerReadyEvent
 153         var pkt Pkt
 154         var ethEvent EthEvent
 155         var peerId *govpn.PeerId
 156         var peerConf *govpn.PeerConf
 157         var handshakeProcessForce bool
 158         ethSink := make(chan EthEvent)
 159
 160         log.Println(govpn.VersionGet())
 161         log.Println("Max MTU on TAP interface:", govpn.TAPMaxMTU())
 162         if *stats != "" {
 163                 log.Println("Stats are going to listen on", *stats)
 164                 statsPort, err := net.Listen("tcp", *stats)
 165                 if err != nil {
 166                         log.Fatalln("Can not listen on stats port:", err)
 167                 }
 168                 go govpn.StatsProcessor(statsPort, &knownPeers)
 169         }
 170         log.Println("Server started")
 171
 172 MainCycle:
 173         for {
 174                 select {
 175                 case <-termSignal:
 176                         break MainCycle
 177                 case <-hsHeartbeat:
 178                         now := time.Now()
 179                         for addr, hs := range states {
 180                                 if hs.LastPing.Add(timeout).Before(now) {
 181                                         log.Println("Deleting handshake state", addr)
 182                                         hs.Zero()
 183                                         delete(states, addr)
 184                                 }
 185                         }
 186                         for addr, state := range peers {
 187                                 if state.peer.LastPing.Add(timeout).Before(now) {
 188                                         log.Println("Deleting peer", state.peer)
 189                                         delete(peers, addr)
 190                                         delete(knownPeers, addr)
 191                                         downPath := path.Join(
 192                                                 govpn.PeersPath,
 193                                                 state.peer.Id.String(),
 194                                                 "down.sh",
 195                                         )
 196                                         go govpn.ScriptCall(downPath, state.tap.Name)
 197                                         state.terminate <- struct{}{}
 198                                         state.peer.Zero()
 199                                 }
 200                         }
 201                 case peerReady = <-peerReadySink:
 202                         for addr, state := range peers {
 203                                 if state.tap.Name != peerReady.iface {
 204                                         continue
 205                                 }
 206                                 delete(peers, addr)
 207                                 delete(knownPeers, addr)
 208                                 state.terminate <- struct{}{}
 209                                 state.peer.Zero()
 210                                 break
 211                         }
 212                         state := NewPeerState(peerReady.peer, peerReady.iface)
 213                         if state == nil {
 214                                 continue
 215                         }
 216                         peers[peerReady.peer.Addr] = state
 217                         knownPeers[peerReady.peer.Addr] = &peerReady.peer
 218                         states[peerReady.peer.Addr].Zero()
 219                         delete(states, peerReady.peer.Addr)
 220                         log.Println("Registered interface", peerReady.iface, "with peer", peer)
 221                         go func(state *PeerState) {
 222                                 for data := range state.sink {
 223                                         ethSink <- EthEvent{
 224                                                 peer:  state.peer,
 225                                                 data:  data,
 226                                                 ready: state.ready,
 227                                         }
 228                                 }
 229                         }(state)
 230                 case ethEvent = <-ethSink:
 231                         if s, exists := peers[ethEvent.peer.Addr]; !exists || s.peer != ethEvent.peer {
 232                                 continue
 233                         }
 234                         ethEvent.peer.EthProcess(ethEvent.data, ethEvent.ready)
 235                 case pkt = <-sink:
 236                         if pkt.data == nil {
 237                                 ready <- struct{}{}
 238                                 continue
 239                         }
 240                         handshakeProcessForce = false
 241                 HandshakeProcess:
 242                         if _, exists = peers[pkt.addr]; handshakeProcessForce || !exists {
 243                                 peerId = govpn.IDsCache.Find(pkt.data)
 244                                 if peerId == nil {
 245                                         log.Println("Unknown identity from", pkt.addr)
 246                                         ready <- struct{}{}
 247                                         continue
 248                                 }
 249                                 peerConf = peerId.Conf()
 250                                 if peerConf == nil {
 251                                         log.Println("Can not get peer configuration", peerId.String())
 252                                         ready <- struct{}{}
 253                                         continue
 254                                 }
 255                                 state, exists = states[pkt.addr]
 256                                 if !exists {
 257                                         state = govpn.HandshakeNew(pkt.addr, pkt.conn, peerConf)
 258                                         states[pkt.addr] = state
 259                                 }
 260                                 peer = state.Server(pkt.data)
 261                                 if peer != nil {
 262                                         log.Println("Peer handshake finished", peer)
 263                                         if _, exists = peers[pkt.addr]; exists {
 264                                                 go func() {
 265                                                         peerReadySink <- PeerReadyEvent{
 266                                                                 peer, peers[pkt.addr].tap.Name,
 267                                                         }
 268                                                 }()
 269                                         } else {
 270                                                 go func() {
 271                                                         upPath := path.Join(govpn.PeersPath, peer.Id.String(), "up.sh")
 272                                                         result, err := govpn.ScriptCall(upPath, "")
 273                                                         if err != nil {
 274                                                                 return
 275                                                         }
 276                                                         sepIndex := bytes.Index(result, []byte{'\n'})
 277                                                         if sepIndex < 0 {
 278                                                                 sepIndex = len(result)
 279                                                         }
 280                                                         ifaceName := string(result[:sepIndex])
 281                                                         peerReadySink <- PeerReadyEvent{peer, ifaceName}
 282                                                 }()
 283                                         }
 284                                 }
 285                                 if !handshakeProcessForce {
 286                                         ready <- struct{}{}
 287                                 }
 288                                 continue
 289                         }
 290                         peerState, exists = peers[pkt.addr]
 291                         if !exists {
 292                                 ready <- struct{}{}
 293                                 continue
 294                         }
 295                         // If it fails during processing, then try to work with it
 296                         // as with handshake packet
 297                         if !peerState.peer.PktProcess(pkt.data, peerState.tap, ready) {
 298                                 handshakeProcessForce = true
 299                                 goto HandshakeProcess
 300                         }
 301                 }
 302         }
 303 }