src/cypherpunks.ru/govpn/cmd/govpn-server/udp.go

   1 /*
   2 GoVPN -- simple secure free software virtual private network daemon
   3 Copyright (C) 2014-2017 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 package main
  20
  21 import (
  22         "log"
  23         "net"
  24
  25         "cypherpunks.ru/govpn"
  26 )
  27
  28 type UDPSender struct {
  29         conn *net.UDPConn
  30         addr *net.UDPAddr
  31 }
  32
  33 func (c UDPSender) Write(data []byte) (int, error) {
  34         return c.conn.WriteToUDP(data, c.addr)
  35 }
  36
  37 var (
  38         // Buffers for UDP parallel processing
  39         udpBufs = make(chan []byte, 1<<8)
  40 )
  41
  42 func startUDP() {
  43         bind, err := net.ResolveUDPAddr("udp", *bindAddr)
  44         if err != nil {
  45                 log.Fatalln("Can not resolve bind address:", err)
  46         }
  47         conn, err := net.ListenUDP("udp", bind)
  48         if err != nil {
  49                 log.Fatalln("Can not listen on UDP:", err)
  50         }
  51         govpn.BothPrintf(`[udp-listen bind="%s"]`, *bindAddr)
  52
  53         udpBufs <- make([]byte, govpn.MTUMax)
  54         go func() {
  55                 var buf []byte
  56                 var raddr *net.UDPAddr
  57                 var addr string
  58                 var n int
  59                 var err error
  60                 var exists bool
  61                 var psI interface{}
  62                 var ps *PeerState
  63                 var hsI interface{}
  64                 var hs *govpn.Handshake
  65                 var addrPrevI interface{}
  66                 var addrPrev string
  67                 var peerPrevI interface{}
  68                 var peerPrev *PeerState
  69                 var peerID *govpn.PeerID
  70                 var conf *govpn.PeerConf
  71                 for {
  72                         buf = <-udpBufs
  73                         n, raddr, err = conn.ReadFromUDP(buf)
  74                         if err != nil {
  75                                 govpn.Printf(`[receive-failed bind="%s" err="%s"]`, *bindAddr, err)
  76                                 break
  77                         }
  78                         addr = raddr.String()
  79
  80                         psI, exists = peers.Load(addr)
  81                         if exists {
  82                                 ps = psI.(*PeerState)
  83                                 go func(peer *govpn.Peer, tap *govpn.TAP, buf []byte, n int) {
  84                                         peer.PktProcess(buf[:n], tap, true)
  85                                         udpBufs <- buf
  86                                 }(ps.peer, ps.tap, buf, n)
  87                                 continue
  88                         }
  89
  90                         hsI, exists = handshakes.Load(addr)
  91                         if !exists {
  92                                 peerID = idsCache.Find(buf[:n])
  93                                 if peerID == nil {
  94                                         govpn.Printf(`[identity-unknown bind="%s" addr="%s"]`, *bindAddr, addr)
  95                                         udpBufs <- buf
  96                                         continue
  97                                 }
  98                                 conf = confs[*peerID]
  99                                 if conf == nil {
 100                                         govpn.Printf(
 101                                                 `[conf-get-failed bind="%s" peer="%s"]`,
 102                                                 *bindAddr, peerID.String(),
 103                                         )
 104                                         udpBufs <- buf
 105                                         continue
 106                                 }
 107                                 hs := govpn.NewHandshake(
 108                                         addr,
 109                                         UDPSender{conn: conn, addr: raddr},
 110                                         conf,
 111                                 )
 112                                 hs.Server(buf[:n])
 113                                 udpBufs <- buf
 114                                 handshakes.Store(addr, hs)
 115                                 continue
 116                         }
 117
 118                         hs = hsI.(*govpn.Handshake)
 119                         peer := hs.Server(buf[:n])
 120                         if peer == nil {
 121                                 udpBufs <- buf
 122                                 continue
 123                         }
 124                         govpn.Printf(
 125                                 `[handshake-completed bind="%s" addr="%s" peer="%s"]`,
 126                                 *bindAddr, addr, peerID.String(),
 127                         )
 128                         hs.Zero()
 129                         handshakes.Delete(addr)
 130
 131                         go func() {
 132                                 udpBufs <- make([]byte, govpn.MTUMax)
 133                                 udpBufs <- make([]byte, govpn.MTUMax)
 134                         }()
 135                         addrPrevI, exists = peersByID.Load(*peer.ID)
 136                         if exists {
 137                                 addrPrev = addrPrevI.(string)
 138                                 peerPrevI, exists = peers.Load(addrPrev)
 139                                 if exists {
 140                                         peerPrev = peerPrevI.(*PeerState)
 141                                         exists = peerPrev == nil
 142                                 }
 143                         }
 144                         if exists {
 145                                 peerPrev.terminator <- struct{}{}
 146                                 psNew := &PeerState{
 147                                         peer:       peer,
 148                                         tap:        peerPrev.tap,
 149                                         terminator: make(chan struct{}),
 150                                 }
 151                                 go func(peer *govpn.Peer, tap *govpn.TAP, terminator chan struct{}) {
 152                                         govpn.PeerTapProcessor(peer, tap, terminator)
 153                                         <-udpBufs
 154                                         <-udpBufs
 155                                 }(psNew.peer, psNew.tap, psNew.terminator)
 156                                 peers.Delete(addrPrev)
 157                                 peers.Store(addr, psNew)
 158                                 knownPeers.Delete(addrPrev)
 159                                 knownPeers.Store(addr, &peer)
 160                                 peersByID.Store(*peer.ID, addr)
 161                                 govpn.Printf(
 162                                         `[rehandshake-completed bind="%s" peer="%s"]`,
 163                                         *bindAddr, peer.ID.String(),
 164                                 )
 165                         } else {
 166                                 go func(addr string, peer *govpn.Peer) {
 167                                         ifaceName, err := callUp(peer.ID, peer.Addr)
 168                                         if err != nil {
 169                                                 return
 170                                         }
 171                                         tap, err := govpn.TAPListen(ifaceName, peer.MTU)
 172                                         if err != nil {
 173                                                 govpn.Printf(
 174                                                         `[tap-failed bind="%s" peer="%s" err="%s"]`,
 175                                                         *bindAddr, peer.ID.String(), err,
 176                                                 )
 177                                                 return
 178                                         }
 179                                         psNew := &PeerState{
 180                                                 peer:       peer,
 181                                                 tap:        tap,
 182                                                 terminator: make(chan struct{}),
 183                                         }
 184                                         go func(peer *govpn.Peer, tap *govpn.TAP, terminator chan struct{}) {
 185                                                 govpn.PeerTapProcessor(peer, tap, terminator)
 186                                                 <-udpBufs
 187                                                 <-udpBufs
 188                                         }(psNew.peer, psNew.tap, psNew.terminator)
 189                                         peers.Store(addr, psNew)
 190                                         knownPeers.Store(addr, &peer)
 191                                         peersByID.Store(*peer.ID, addr)
 192                                         govpn.Printf(
 193                                                 `[peer-created bind="%s" peer="%s"]`,
 194                                                 *bindAddr,
 195                                                 peer.ID.String(),
 196                                         )
 197                                 }(addr, peer)
 198                         }
 199                         udpBufs <- buf
 200                 }
 201         }()
 202 }