src/cypherpunks.ru/govpn/server/tcp.go

   1 /*
   2 GoVPN -- simple secure free software virtual private network daemon
   3 Copyright (C) 2014-2016 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 server
  20
  21 import (
  22         "bytes"
  23         "net"
  24         "time"
  25
  26         "github.com/Sirupsen/logrus"
  27         "github.com/pkg/errors"
  28
  29         "cypherpunks.ru/govpn"
  30 )
  31
  32 func (s *Server) startTCP() {
  33         bind, err := net.ResolveTCPAddr("tcp", s.configuration.BindAddress)
  34         if err != nil {
  35                 s.Error <- errors.Wrap(err, "net.ResolveTCPAddr")
  36                 return
  37         }
  38         listener, err := net.ListenTCP("tcp", bind)
  39         if err != nil {
  40                 s.Error <- errors.Wrapf(err, "net.ListenTCP %q", bind.String())
  41                 return
  42         }
  43         fields := logrus.Fields{
  44                 "func": logFuncPrefix + "Server.startTCP",
  45                 "bind": bind.String(),
  46         }
  47         s.logger.WithFields(fields).WithFields(s.LogFields()).WithFields(s.configuration.LogFields()).Info("Listen")
  48         go func() {
  49                 for {
  50                         conn, err := listener.AcceptTCP()
  51                         if err != nil {
  52                                 s.logger.WithError(err).WithFields(fields).WithFields(s.LogFields()).Error("Failed to accept TCP connection")
  53                                 continue
  54                         }
  55                         go s.handleTCP(conn)
  56                 }
  57         }()
  58 }
  59
  60 func (s *Server) handleTCP(conn net.Conn) {
  61         addr := conn.RemoteAddr().String()
  62         buf := make([]byte, govpn.EnclessEnlargeSize+2*govpn.MTUMax)
  63         var n int
  64         var err error
  65         var prev int
  66         var hs *govpn.Handshake
  67         var ps *PeerState
  68         var peer *govpn.Peer
  69         var deadLine time.Time
  70         var tap *govpn.TAP
  71         var conf *govpn.PeerConf
  72         fields := logrus.Fields{
  73                 "func":   logFuncPrefix + "Server.handleTCP",
  74                 "remote": addr,
  75         }
  76         for {
  77                 if prev == len(buf) {
  78                         // TODO log why
  79                         break
  80                 }
  81
  82                 deadLine = time.Now().Add(govpn.TimeoutDefault)
  83                 if err = conn.SetReadDeadline(deadLine); err != nil {
  84                         s.Error <- errors.Wrapf(err, "conn.SetReadDeadline %s", deadLine.String())
  85                         return
  86                 }
  87                 n, err = conn.Read(buf[prev:])
  88                 if err != nil {
  89                         s.logger.WithFields(fields).WithFields(s.LogFields()).WithError(err).Debug("Can't read connection: either EOFed or timeouted")
  90                         break
  91                 }
  92                 prev += n
  93                 peerID, err := s.idsCache.Find(buf[:prev])
  94                 if err != nil {
  95                         s.logger.WithFields(fields).WithFields(s.LogFields()).WithError(err).Debug("Couldn't lookup for peer in ids")
  96                         continue
  97                 }
  98                 if peerID == nil {
  99                         s.logger.WithFields(fields).WithFields(s.LogFields()).Debug("Couldn't find peer")
 100                         continue
 101                 }
 102                 if hs == nil {
 103                         conf = s.confs.Get(*peerID)
 104                         if conf == nil {
 105                                 s.logger.WithFields(fields).WithFields(s.LogFields()).WithFields(s.configuration.LogFields()).Error("Configuration get failed")
 106                                 break
 107                         }
 108                         hs = govpn.NewHandshake(addr, conn, conf)
 109                 }
 110                 peer, err = hs.Server(buf[:prev])
 111                 if err != nil {
 112                         s.logger.WithFields(fields).WithError(err).WithFields(s.LogFields()).Error("Can't create new peer")
 113                         continue
 114                 }
 115                 prev = 0
 116                 if peer == nil {
 117                         continue
 118                 }
 119
 120                 s.logger.WithFields(fields).WithFields(s.LogFields()).WithFields(peer.LogFields()).Info("Handshake completed")
 121
 122                 hs.Zero()
 123                 s.peersByIDLock.RLock()
 124                 addrPrev, exists := s.peersByID[*peer.ID]
 125                 s.peersByIDLock.RUnlock()
 126
 127                 if exists {
 128                         s.peersLock.Lock()
 129                         s.peers[addrPrev].terminator <- struct{}{}
 130                         tap = s.peers[addrPrev].tap
 131                         ps = &PeerState{
 132                                 peer:       peer,
 133                                 tap:        tap,
 134                                 terminator: make(chan struct{}),
 135                         }
 136                         peer.Protocol = govpn.ProtocolTCP
 137                         go govpn.PeerTapProcessor(ps.peer, ps.tap, ps.terminator)
 138                         s.peersByIDLock.Lock()
 139                         s.kpLock.Lock()
 140                         delete(s.peers, addrPrev)
 141                         delete(s.knownPeers, addrPrev)
 142                         s.peers[addr] = ps
 143                         s.knownPeers[addr] = &peer
 144                         s.peersByID[*peer.ID] = addr
 145                         s.peersLock.Unlock()
 146                         s.peersByIDLock.Unlock()
 147                         s.kpLock.Unlock()
 148                         s.logger.WithFields(fields).WithFields(s.LogFields()).WithFields(peer.LogFields()).Debug("Rehandshake completed")
 149                 } else {
 150                         tap, err = s.callUp(peer, govpn.ProtocolTCP)
 151                         if err != nil {
 152                                 s.logger.WithFields(fields).WithFields(s.LogFields()).WithFields(peer.LogFields()).WithError(err).Error("TAP failed")
 153                                 peer = nil
 154                                 break
 155                         }
 156                         ps = &PeerState{
 157                                 peer:       peer,
 158                                 tap:        tap,
 159                                 terminator: make(chan struct{}, 1),
 160                         }
 161                         peer.Protocol = govpn.ProtocolTCP
 162                         go govpn.PeerTapProcessor(ps.peer, ps.tap, ps.terminator)
 163                         s.peersLock.Lock()
 164                         s.peersByIDLock.Lock()
 165                         s.kpLock.Lock()
 166                         s.peers[addr] = ps
 167                         s.peersByID[*peer.ID] = addr
 168                         s.knownPeers[addr] = &peer
 169                         s.peersLock.Unlock()
 170                         s.peersByIDLock.Unlock()
 171                         s.kpLock.Unlock()
 172                         s.logger.WithFields(fields).WithFields(s.LogFields()).WithFields(peer.LogFields()).Info("Peer created")
 173                 }
 174                 break
 175         }
 176         if hs != nil {
 177                 hs.Zero()
 178         }
 179         if peer == nil {
 180                 return
 181         }
 182
 183         prev = 0
 184         var i int
 185         for {
 186                 if prev == len(buf) {
 187                         break
 188                 }
 189                 deadLine = time.Now().Add(conf.Timeout)
 190                 if err = conn.SetReadDeadline(deadLine); err != nil {
 191                         s.Error <- errors.Wrapf(err, "conn.SetReadDeadline %s", deadLine.String())
 192                         return
 193                 }
 194                 n, err = conn.Read(buf[prev:])
 195                 if err != nil {
 196                         s.logger.WithFields(fields).WithFields(s.LogFields()).WithError(err).Debug("Can't read connection: either EOFed or timeouted")
 197                         break
 198                 }
 199                 prev += n
 200         CheckMore:
 201                 if prev < govpn.MinPktLength {
 202                         continue
 203                 }
 204                 i = bytes.Index(buf[:prev], peer.NonceExpect)
 205                 if i == -1 {
 206                         continue
 207                 }
 208                 if !peer.PktProcess(buf[:i+govpn.NonceSize], tap, false) {
 209                         s.logger.WithFields(fields).WithFields(s.LogFields()).WithFields(peer.LogFields()).Warn("Packet unauthenticated")
 210                         break
 211                 }
 212                 copy(buf, buf[i+govpn.NonceSize:prev])
 213                 prev = prev - i - govpn.NonceSize
 214                 goto CheckMore
 215         }
 216         peer.Zero()
 217 }