src/cypherpunks.ru/govpn/server/server.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         "sync"
  23         "time"
  24
  25         "github.com/Sirupsen/logrus"
  26         "github.com/pkg/errors"
  27
  28         "cypherpunks.ru/govpn"
  29 )
  30
  31 // PeerConfigurer is used by a GoVPN server to figure the configuration of a single peer
  32 type PeerConfigurer interface {
  33         Get(govpn.PeerID) *govpn.PeerConf
  34 }
  35
  36 // MACPeerFinder is used by GoVPN server to figure the PeerID from handshake data
  37 type MACPeerFinder interface {
  38         Find([]byte) (*govpn.PeerID, error)
  39 }
  40
  41 // PeerState hold server side state of a single connecting/connected peer
  42 type PeerState struct {
  43         peer       *govpn.Peer
  44         terminator chan struct{}
  45         tap        *govpn.TAP
  46 }
  47
  48 // Configuration hold GoVPN server configuration
  49 type Configuration struct {
  50         BindAddress  string
  51         ProxyAddress string
  52         Protocol     govpn.Protocol
  53         Timeout      time.Duration
  54 }
  55
  56 // Validate return an error if a configuration is invalid
  57 func (c *Configuration) Validate() error {
  58         if len(c.BindAddress) == 0 {
  59                 return errors.New("Missing BindAddress")
  60         }
  61         return nil
  62 }
  63
  64 // LogFields return a logrus compatible logging context
  65 func (c *Configuration) LogFields() logrus.Fields {
  66         const prefix = "srv_conf_"
  67         f := logrus.Fields{
  68                 prefix + "bind":     c.BindAddress,
  69                 prefix + "protocol": c.Protocol.String(),
  70                 prefix + "timeout":  c.Timeout.String(),
  71         }
  72         if len(c.ProxyAddress) > 0 {
  73                 f[prefix+"proxy"] = c.ProxyAddress
  74         }
  75         return f
  76 }
  77
  78 // Server is a GoVPN server instance
  79 type Server struct {
  80         configuration Configuration
  81         termSignal    chan interface{}
  82
  83         idsCache MACPeerFinder
  84         confs    PeerConfigurer
  85
  86         handshakes map[string]*govpn.Handshake
  87         hsLock     sync.RWMutex
  88
  89         peers     map[string]*PeerState
  90         peersLock sync.RWMutex
  91
  92         peersByID     map[govpn.PeerID]string
  93         peersByIDLock sync.RWMutex
  94
  95         knownPeers govpn.KnownPeers
  96         kpLock     sync.RWMutex
  97
  98         logger *logrus.Logger
  99
 100         // Error channel receives any kind of routine errors
 101         Error chan error
 102 }
 103
 104 // LogFields return a logrus compatible logging context
 105 func (s *Server) LogFields() logrus.Fields {
 106         const prefix = "srv_"
 107         return logrus.Fields{
 108                 prefix + "hs":    len(s.handshakes),
 109                 prefix + "peers": len(s.peers),
 110                 prefix + "known": len(s.knownPeers),
 111         }
 112 }
 113
 114 // KnownPeers return GoVPN peers.
 115 // used to get client statistics.
 116 func (s *Server) KnownPeers() *govpn.KnownPeers {
 117         return &s.knownPeers
 118 }
 119
 120 // NewServer return a configured GoVPN server, to listen network connection MainCycle must be executed
 121 func NewServer(serverConf Configuration, peerConfs PeerConfigurer, idsCache MACPeerFinder, logger *logrus.Logger, termSignal chan interface{}) *Server {
 122         govpn.SetLogger(logger)
 123         return &Server{
 124                 configuration: serverConf,
 125                 confs:         peerConfs,
 126                 termSignal:    termSignal,
 127                 idsCache:      idsCache,
 128                 handshakes:    make(map[string]*govpn.Handshake),
 129                 peers:         make(map[string]*PeerState),
 130                 peersByID:     make(map[govpn.PeerID]string),
 131                 knownPeers:    govpn.KnownPeers(make(map[string]**govpn.Peer)),
 132                 Error:         make(chan error, 1),
 133                 logger:        logger,
 134         }
 135 }
 136
 137 // MainCycle main loop that handle connecting/connected client
 138 func (s *Server) MainCycle() {
 139         switch s.configuration.Protocol {
 140         case govpn.ProtocolUDP:
 141                 s.startUDP()
 142         case govpn.ProtocolTCP:
 143                 s.startTCP()
 144         case govpn.ProtocolALL:
 145                 s.startUDP()
 146                 s.startTCP()
 147         default:
 148                 s.Error <- errors.New("Unknown protocol specified")
 149                 return
 150         }
 151
 152         if len(s.configuration.ProxyAddress) > 0 {
 153                 go s.proxyStart()
 154         }
 155         fields := logrus.Fields{"func": logFuncPrefix + "Server.MainCycle"}
 156
 157         s.logger.WithFields(fields).WithFields(s.LogFields()).WithFields(s.configuration.LogFields()).Info("Starting...")
 158
 159         var needsDeletion bool
 160         var err error
 161         hsHeartbeat := time.Tick(s.configuration.Timeout)
 162         go func() { <-hsHeartbeat }()
 163
 164 MainCycle:
 165         for {
 166                 select {
 167                 case <-s.termSignal:
 168                         s.logger.WithFields(fields).WithFields(s.LogFields()).WithFields(s.configuration.LogFields()).Info("Terminating")
 169                         for _, ps := range s.peers {
 170                                 if err = s.callDown(ps); err != nil {
 171                                         s.logger.WithFields(fields).WithError(err).WithFields(ps.peer.LogFields()).Error("Failed to run callDown")
 172                                 }
 173                                 if err = ps.tap.Close(); err != nil {
 174                                         logrus.WithError(err).WithFields(fields).WithFields(ps.peer.LogFields()).Error("Couldn't close TAP")
 175                                 }
 176                         }
 177                         // empty value signals that everything is fine
 178                         s.Error <- nil
 179                         break MainCycle
 180                 case <-hsHeartbeat:
 181                         logrus.WithFields(fields).Debug("Heartbeat")
 182                         now := time.Now()
 183                         s.hsLock.Lock()
 184                         for addr, hs := range s.handshakes {
 185                                 if hs.LastPing.Add(s.configuration.Timeout).Before(now) {
 186                                         logrus.WithFields(fields).WithFields(hs.LogFields()).Debug("handshake is expired, delete")
 187                                         hs.Zero()
 188                                         delete(s.handshakes, addr)
 189                                 }
 190                         }
 191                         s.peersLock.Lock()
 192                         s.peersByIDLock.Lock()
 193                         s.kpLock.Lock()
 194                         for addr, ps := range s.peers {
 195                                 ps.peer.BusyR.Lock()
 196                                 needsDeletion = ps.peer.LastPing.Add(s.configuration.Timeout).Before(now)
 197                                 ps.peer.BusyR.Unlock()
 198                                 if needsDeletion {
 199                                         logrus.WithFields(fields).WithFields(ps.peer.LogFields()).Info("Delete peer")
 200                                         delete(s.peers, addr)
 201                                         delete(s.knownPeers, addr)
 202                                         delete(s.peersByID, *ps.peer.ID)
 203                                         if err = s.callDown(ps); err != nil {
 204                                                 logrus.WithError(err).WithFields(fields).WithFields(ps.peer.LogFields()).Error("Couldn't execute callDown")
 205                                         }
 206                                         if err = ps.tap.Close(); err != nil {
 207                                                 logrus.WithError(err).WithFields(fields).WithFields(ps.peer.LogFields()).Error("Couldn't close TAP")
 208                                         }
 209                                         ps.terminator <- struct{}{}
 210                                 }
 211                         }
 212                         s.hsLock.Unlock()
 213                         s.peersLock.Unlock()
 214                         s.peersByIDLock.Unlock()
 215                         s.kpLock.Unlock()
 216                 }
 217         }
 218 }