src/cypherpunks.ru/govpn/cmd/govpn-server/tcp.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         "bytes"
  23         "log"
  24         "net"
  25         "time"
  26
  27         "cypherpunks.ru/govpn"
  28 )
  29
  30 func startTCP() {
  31         bind, err := net.ResolveTCPAddr("tcp", *bindAddr)
  32         if err != nil {
  33                 log.Fatalln("Can not resolve bind address:", err)
  34         }
  35         listener, err := net.ListenTCP("tcp", bind)
  36         if err != nil {
  37                 log.Fatalln("Can not listen on TCP:", err)
  38         }
  39         govpn.BothPrintf(`[tcp-listen bind="%s"]`, *bindAddr)
  40         go func() {
  41                 for {
  42                         conn, err := listener.AcceptTCP()
  43                         if err != nil {
  44                                 govpn.Printf(`[tcp-accept-failed bind="%s" err="%s"]`, *bindAddr, err)
  45                                 continue
  46                         }
  47                         go handleTCP(conn)
  48                 }
  49         }()
  50 }
  51
  52 func handleTCP(conn net.Conn) {
  53         addr := conn.RemoteAddr().String()
  54         buf := make([]byte, govpn.EnclessEnlargeSize+2*govpn.MTUMax)
  55         var n int
  56         var err error
  57         var prev int
  58         var hs *govpn.Handshake
  59         var ps *PeerState
  60         var peer *govpn.Peer
  61         var tap *govpn.TAP
  62         var conf *govpn.PeerConf
  63         for {
  64                 if prev == len(buf) {
  65                         break
  66                 }
  67                 conn.SetReadDeadline(time.Now().Add(time.Duration(govpn.TimeoutDefault) * time.Second))
  68                 n, err = conn.Read(buf[prev:])
  69                 if err != nil {
  70                         // Either EOFed or timeouted
  71                         break
  72                 }
  73                 prev += n
  74                 peerID := idsCache.Find(buf[:prev])
  75                 if peerID == nil {
  76                         continue
  77                 }
  78                 if hs == nil {
  79                         conf = confs[*peerID]
  80                         if conf == nil {
  81                                 govpn.Printf(
  82                                         `[conf-get-failed bind="%s" peer="%s"]`,
  83                                         *bindAddr, peerID.String(),
  84                                 )
  85                                 break
  86                         }
  87                         hs = govpn.NewHandshake(addr, conn, conf)
  88                 }
  89                 peer = hs.Server(buf[:prev])
  90                 prev = 0
  91                 if peer == nil {
  92                         continue
  93                 }
  94                 hs.Zero()
  95                 govpn.Printf(
  96                         `[handshake-completed bind="%s" addr="%s" peer="%s"]`,
  97                         *bindAddr, addr, peerID.String(),
  98                 )
  99                 peersByIDLock.RLock()
 100                 addrPrev, exists := peersByID[*peer.ID]
 101                 peersByIDLock.RUnlock()
 102                 var peerPrev *PeerState
 103                 if exists {
 104                         peersLock.Lock()
 105                         peerPrev = peers[addrPrev]
 106                         if peerPrev == nil {
 107                                 exists = false
 108                                 peersLock.Unlock()
 109                         }
 110                 }
 111                 if exists {
 112                         peerPrev.terminator <- struct{}{}
 113                         tap = peerPrev.tap
 114                         ps = &PeerState{
 115                                 peer:       peer,
 116                                 tap:        tap,
 117                                 terminator: make(chan struct{}),
 118                         }
 119                         go govpn.PeerTapProcessor(ps.peer, ps.tap, ps.terminator)
 120                         peersByIDLock.Lock()
 121                         kpLock.Lock()
 122                         delete(peers, addrPrev)
 123                         delete(knownPeers, addrPrev)
 124                         peers[addr] = ps
 125                         knownPeers[addr] = &peer
 126                         peersByID[*peer.ID] = addr
 127                         peersLock.Unlock()
 128                         peersByIDLock.Unlock()
 129                         kpLock.Unlock()
 130                         govpn.Printf(
 131                                 `[rehandshake-completed bind="%s" peer="%s"]`,
 132                                 *bindAddr, peerID.String(),
 133                         )
 134                 } else {
 135                         ifaceName, err := callUp(peer.ID, peer.Addr)
 136                         if err != nil {
 137                                 peer = nil
 138                                 break
 139                         }
 140                         tap, err = govpn.TAPListen(ifaceName, peer.MTU)
 141                         if err != nil {
 142                                 govpn.Printf(
 143                                         `[tap-failed bind="%s" peer="%s" err="%s"]`,
 144                                         *bindAddr, peerID.String(), err,
 145                                 )
 146                                 peer = nil
 147                                 break
 148                         }
 149                         ps = &PeerState{
 150                                 peer:       peer,
 151                                 tap:        tap,
 152                                 terminator: make(chan struct{}, 1),
 153                         }
 154                         go govpn.PeerTapProcessor(ps.peer, ps.tap, ps.terminator)
 155                         peersLock.Lock()
 156                         peersByIDLock.Lock()
 157                         kpLock.Lock()
 158                         peers[addr] = ps
 159                         peersByID[*peer.ID] = addr
 160                         knownPeers[addr] = &peer
 161                         peersLock.Unlock()
 162                         peersByIDLock.Unlock()
 163                         kpLock.Unlock()
 164                         govpn.Printf(`[peer-created bind="%s" peer="%s"]`, *bindAddr, peerID.String())
 165                 }
 166                 break
 167         }
 168         if hs != nil {
 169                 hs.Zero()
 170         }
 171         if peer == nil {
 172                 return
 173         }
 174
 175         prev = 0
 176         var i int
 177         for {
 178                 if prev == len(buf) {
 179                         break
 180                 }
 181                 conn.SetReadDeadline(time.Now().Add(conf.Timeout))
 182                 n, err = conn.Read(buf[prev:])
 183                 if err != nil {
 184                         // Either EOFed or timeouted
 185                         break
 186                 }
 187                 prev += n
 188         CheckMore:
 189                 if prev < govpn.MinPktLength {
 190                         continue
 191                 }
 192                 i = bytes.Index(buf[:prev], peer.NonceExpect)
 193                 if i == -1 {
 194                         continue
 195                 }
 196                 if !peer.PktProcess(buf[:i+govpn.NonceSize], tap, false) {
 197                         govpn.Printf(
 198                                 `[packet-unauthenticated bind="%s" addr="%s" peer="%s"]`,
 199                                 *bindAddr, addr, peer.ID.String(),
 200                         )
 201                         break
 202                 }
 203                 copy(buf, buf[i+govpn.NonceSize:prev])
 204                 prev = prev - i - govpn.NonceSize
 205                 goto CheckMore
 206         }
 207         peer.Zero()
 208 }