src/MultiPlayer/multiplayrxmgr.cxx

   1 // multiplayrxmgr.cxx -- routines for receiving multiplayer data
   2 //                       for Flightgear
   3 //
   4 // Written by Duncan McCreanor, started February 2003.
   5 // duncan.mccreanor@airservicesaustralia.com
   6 //
   7 // Copyright (C) 2003  Airservices Australia
   8 //
   9 // This program is free software; you can redistribute it and/or
  10 // modify it under the terms of the GNU General Public License as
  11 // published by the Free Software Foundation; either version 2 of the
  12 // License, or (at your option) any later version.
  13 //
  14 // This program is distributed in the hope that it will be useful, but
  15 // WITHOUT ANY WARRANTY; without even the implied warranty of
  16 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17 // General Public License for more details.
  18 //
  19 // You should have received a copy of the GNU General Public License
  20 // along with this program; if not, write to the Free Software
  21 // Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22 //
  23
  24
  25 /******************************************************************
  26 * $Id$
  27 *
  28 * Description: The multiplayer rx manager provides control over
  29 * multiplayer data reception and processing for an interactive
  30 * multiplayer FlightGear simulation.
  31 *
  32 * The objects that hold player information are accessed via
  33 * a fixed size array. A fixed array is used since it provides
  34 * speed benefits over working with linked lists and is easier
  35 * to code. Also, there is no point allowing for an unlimited
  36 * number of players as too many players will slow the game
  37 * down to the point where it is unplayable.
  38 *
  39 * When player position data is received, the callsign of
  40 * the player is checked against existing players. If the
  41 * player does not exist, a new player is created in the
  42 * next free slot of the player array. If the player does
  43 * exist, the player's positional matrix is updated.
  44 *
  45 * The Update method is used to move the players on the
  46 * scene. The return value from calling MPPlayer::Draw
  47 * indicates the state of the player. If data for a player
  48 * has not been received data for some time, the player object
  49 * is deleted and the array element freed.
  50 *
  51 ******************************************************************/
  52
  53 #include <sys/types.h>
  54 #include <sys/socket.h>
  55 #include <netinet/in.h>
  56 #include <arpa/inet.h>
  57 #include <plib/netSocket.h>
  58 #include <stdlib.h>
  59
  60 #include <simgear/debug/logstream.hxx>
  61 #include <Main/fg_props.hxx>
  62
  63 #include "multiplayrxmgr.hxx"
  64 #include "mpmessages.hxx"
  65 #include "mpplayer.hxx"
  66
  67 #define MAX_PACKET_SIZE 1024
  68
  69 // These constants are provided so that the ident command can list file versions.
  70 const char sMULTIPLAYTXMGR_BID[] = "$Id$";
  71 const char sMULTIPLAYRXMGR_HID[] = MULTIPLAYRXMGR_HID;
  72
  73
  74
  75 /******************************************************************
  76 * Name: FGMultiplayRxMgr
  77 * Description: Constructor.
  78 ******************************************************************/
  79 FGMultiplayRxMgr::FGMultiplayRxMgr() {
  80
  81     int iPlayerCnt;         // Count of players in player array
  82
  83     // Initialise private members
  84     m_sRxAddress = "0";
  85     m_iRxPort = 0;
  86     m_bInitialised = false;
  87
  88     // Clear the player array
  89     for (iPlayerCnt = 0; iPlayerCnt < MAX_PLAYERS; iPlayerCnt++) {
  90         m_Player[iPlayerCnt] = NULL;
  91     }
  92
  93 }
  94
  95
  96 /******************************************************************
  97 * Name: ~FGMultiplayRxMgr
  98 * Description: Destructor. Closes and deletes objects owned by
  99 * this object.
 100 ******************************************************************/
 101 FGMultiplayRxMgr::~FGMultiplayRxMgr() {
 102
 103     Close();
 104
 105 }
 106
 107
 108 /******************************************************************
 109 * Name: init
 110 * Description: Initialises multiplayer receive.
 111 ******************************************************************/
 112 bool FGMultiplayRxMgr::init(void) {
 113
 114     bool bSuccess = true;                       // Result of initialisation
 115
 116     // Initialise object if not already done
 117     if (!m_bInitialised) {
 118
 119         // Set members from property values
 120         m_sCallsign = fgGetString("/sim/multiplay/callsign");
 121         m_sRxAddress = fgGetString("/sim/multiplay/rxhost");
 122         m_iRxPort = fgGetInt("/sim/multiplay/rxport");
 123
 124         SG_LOG( SG_NETWORK, SG_INFO, "FGMultiplayRxMgr::init - rxaddress= "
 125                                      << m_sRxAddress );
 126         SG_LOG( SG_NETWORK, SG_INFO, "FGMultiplayRxMgr::init - rxport= "
 127                                      << m_iRxPort);
 128         SG_LOG( SG_NETWORK, SG_INFO, "FGMultiplayRxMgr::init - callsign= "
 129                                      << m_sCallsign );
 130
 131
 132         // Create and open rx socket
 133         mDataRxSocket = new netSocket();
 134         if (!mDataRxSocket->open(false)) {
 135             // Failed to open rx socket
 136             cerr << "FGMultiplayRxMgr::Open - Failed to create data receive socket" << endl;
 137             bSuccess = false;
 138         } else {
 139
 140             // Configure the socket
 141             mDataRxSocket->setBlocking(false);
 142             mDataRxSocket->setBroadcast(true);
 143             if (mDataRxSocket->bind(m_sRxAddress.c_str(), m_iRxPort) != 0) {
 144                 perror("bind");
 145                 // Failed to bind
 146                 cerr << "FGMultiplayRxMgr::Open - Failed to bind receive socket" << endl;
 147                 bSuccess = false;
 148             }
 149
 150         }
 151
 152         // Save manager state
 153         m_bInitialised = bSuccess;
 154
 155     } else {
 156         cerr << "FGMultiplayRxMgr::OpenRx - Receiver open requested when receiver is already open" << endl;
 157         bSuccess = false;
 158     }
 159
 160     /* Return true if open succeeds */
 161     return bSuccess;
 162
 163 }
 164
 165
 166 /******************************************************************
 167 * Name: Close
 168 * Description: Closes and deletes and player connections. Closes
 169 * and deletes the rx socket. Resets the object state
 170 * to unitialised.
 171 ******************************************************************/
 172 void FGMultiplayRxMgr::Close(void) {
 173
 174     int iPlayerCnt;         // Count of players in player array
 175
 176     // Delete any existing players
 177     for (iPlayerCnt = 0; iPlayerCnt < MAX_PLAYERS; iPlayerCnt++) {
 178         if (m_Player[iPlayerCnt] != NULL) {
 179             delete m_Player[iPlayerCnt];
 180             m_Player[iPlayerCnt] = NULL;
 181         }
 182     }
 183
 184     // Delete socket
 185     if (mDataRxSocket) {
 186         mDataRxSocket->close();
 187         delete mDataRxSocket;
 188         mDataRxSocket = NULL;
 189     }
 190
 191     m_bInitialised = false;
 192
 193 }
 194
 195
 196 /******************************************************************
 197 * Name: ProcessData
 198 * Description: Processes data waiting at the receive socket. The
 199 * processing ends when there is no more data at the socket.
 200 ******************************************************************/
 201 void FGMultiplayRxMgr::ProcessData(void) {
 202
 203     char sMsg[MAX_PACKET_SIZE];         // Buffer for received message
 204     int iBytes;                         // Bytes received
 205     T_MsgHdr *MsgHdr;                   // Pointer to header in received data
 206     T_ChatMsg *ChatMsg;                 // Pointer to chat message in received data
 207     T_PositionMsg *PosMsg;              // Pointer to position message in received data
 208     char *sIpAddress;                   // Address information from header
 209     char *sModelName;                   // Model that the remote player is using
 210     char *sCallsign;                    // Callsign of the remote player
 211     struct in_addr PlayerAddress;       // Used for converting the player's address into dot notation
 212     int iPlayerCnt;                     // Count of players in player array
 213     bool bActivePlayer = false;         // The state of the player that sent the data
 214     int iPort;                          // Port that the remote player receives on
 215
 216
 217     if (m_bInitialised) {
 218
 219         // Read the receive socket and process any data
 220         do {
 221
 222             // Although the recv call asks for MAX_PACKET_SIZE of data,
 223             // the number of bytes returned will only be that of the next
 224             // packet waiting to be processed.
 225             iBytes = mDataRxSocket->recv(sMsg, MAX_PACKET_SIZE, 0);
 226
 227             // Data received
 228             if (iBytes > 0) {
 229                 if (iBytes >= sizeof(MsgHdr)) {
 230
 231                     // Read header
 232                     MsgHdr = (T_MsgHdr *)sMsg;
 233                     PlayerAddress.s_addr = MsgHdr->lReplyAddress;
 234                     sIpAddress = inet_ntoa(PlayerAddress);
 235                     iPort = MsgHdr->iReplyPort;
 236                     sCallsign = MsgHdr->sCallsign;
 237
 238                     // Process the player data unless we generated it
 239                     if (m_sCallsign != string(MsgHdr->sCallsign)) {
 240
 241
 242                         // Process messages
 243                         switch(MsgHdr->MsgId) {
 244                             case CHAT_MSG_ID:
 245                                 if (MsgHdr->iMsgLen == sizeof(T_MsgHdr) + sizeof(T_ChatMsg)) {
 246                                     ChatMsg = (T_ChatMsg *)(sMsg + sizeof(T_MsgHdr));
 247                                     SG_LOG( SG_NETWORK, SG_BULK, "Chat [" << MsgHdr->sCallsign << "]" << " " << ChatMsg->sText );
 248                                 } else {
 249                                     SG_LOG( SG_NETWORK, SG_ALERT, "FGMultiplayRxMgr::MP_ProcessData - Chat message received with insufficient data" );
 250                                 }
 251                                 break;
 252
 253                             case POS_DATA_ID:
 254                                 if (MsgHdr->iMsgLen == sizeof(T_MsgHdr) + sizeof(T_PositionMsg)) {
 255                                     PosMsg = (T_PositionMsg *)(sMsg + sizeof(T_MsgHdr));
 256                                     sModelName = PosMsg->sModel;
 257
 258                                     // Check if the player is already in the game by using the Callsign.
 259                                     bActivePlayer = false;
 260                                     for (iPlayerCnt = 0; iPlayerCnt < MAX_PLAYERS; iPlayerCnt++) {
 261                                         if (m_Player[iPlayerCnt] != NULL) {
 262                                             if (m_Player[iPlayerCnt]->CompareCallsign(MsgHdr->sCallsign)) {
 263
 264                                                 // Player found. Update the data for the player.
 265                                                 m_Player[iPlayerCnt]->SetPosition(PosMsg->PlayerPos);
 266                                                 bActivePlayer = true;
 267
 268                                             }
 269                                         }
 270                                     }
 271
 272                                     // Player not active, so add as new player
 273                                     if (!bActivePlayer) {
 274                                         iPlayerCnt = 0;
 275                                         do {
 276                                             if (m_Player[iPlayerCnt] == NULL) {
 277                                                 SG_LOG( SG_NETWORK, SG_INFO, "FGMultiplayRxMgr::ProcessRxData - Add new player. IP: " << sIpAddress << ", Call: " <<  sCallsign << ", model: " << sModelName );
 278                                                 m_Player[iPlayerCnt] = new MPPlayer;
 279                                                 m_Player[iPlayerCnt]->Open(string(sIpAddress), iPort, string(sCallsign), string(sModelName), false);
 280                                                 m_Player[iPlayerCnt]->SetPosition(PosMsg->PlayerPos);
 281                                                 bActivePlayer = true;
 282                                             }
 283                                             iPlayerCnt++;
 284                                         } while (iPlayerCnt < MAX_PLAYERS && !bActivePlayer);
 285
 286                                         // Check if the player was added
 287                                         if (!bActivePlayer) {
 288                                             if (iPlayerCnt == MAX_PLAYERS) {
 289                                                 cerr << "FGMultiplayRxMgr::MP_ProcessData - Unable to add new player (" << sCallsign << "). Too many players." << endl;
 290                                             }
 291                                         }
 292                                     }
 293
 294                                 } else {
 295                                     cerr << "FGMultiplayRxMgr::MP_ProcessData - Position message received with insufficient data" << endl;
 296                                 }
 297                                 break;
 298
 299                             default:
 300                                 cerr << "FGMultiplayRxMgr::MP_ProcessData - Unknown message Id received: " << MsgHdr->MsgId << endl;
 301                                 break;
 302
 303
 304                         }
 305                     }
 306                 }
 307
 308
 309             // Error or no data
 310             } else if (iBytes == -1) {
 311                 if (errno != EAGAIN) {
 312                     perror("FGMultiplayRxMgr::MP_ProcessData");
 313                 }
 314             }
 315
 316         } while (iBytes > 0);
 317
 318     }
 319
 320
 321 }
 322
 323
 324 /******************************************************************
 325 * Name: Update
 326 * Description: For each active player, tell the player object
 327 * to update its position on the scene. If a player object
 328 * returns status information indicating that it has not
 329 * had an update for some time then the player is deleted.
 330 ******************************************************************/
 331 void FGMultiplayRxMgr::Update(void) {
 332
 333     int iPlayerDataState;
 334     int iPlayerId;
 335
 336     for (iPlayerId = 0; iPlayerId < MAX_PLAYERS; iPlayerId++) {
 337         if (m_Player[iPlayerId] != NULL) {
 338             iPlayerDataState = m_Player[iPlayerId]->Draw();
 339
 340             // If the player has not received an update for some
 341             // time then assume that the player has quit.
 342             if (iPlayerDataState == PLAYER_DATA_EXPIRED) {
 343                 delete m_Player[iPlayerId];
 344                 m_Player[iPlayerId] = NULL;
 345             }
 346
 347         }
 348     }
 349
 350 }
 351
 352