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 #include <Main/fg_props.hxx>
  60
  61 #include "multiplayrxmgr.hxx"
  62 #include "mpmessages.hxx"
  63 #include "mpplayer.hxx"
  64
  65 #define MAX_PACKET_SIZE 1024
  66
  67 // These constants are provided so that the ident command can list file versions.
  68 const char sMULTIPLAYTXMGR_BID[] = "$Id$";
  69 const char sMULTIPLAYRXMGR_HID[] = MULTIPLAYRXMGR_HID;
  70
  71
  72
  73 /******************************************************************
  74 * Name: FGMultiplayRxMgr
  75 * Description: Constructor.
  76 ******************************************************************/
  77 FGMultiplayRxMgr::FGMultiplayRxMgr() {
  78
  79     int iPlayerCnt;         // Count of players in player array
  80
  81     // Initialise private members
  82     m_sRxAddress = "0";
  83     m_iRxPort = 0;
  84     m_bInitialised = false;
  85
  86     // Clear the player array
  87     for (iPlayerCnt = 0; iPlayerCnt < MAX_PLAYERS; iPlayerCnt++) {
  88         m_Player[iPlayerCnt] = NULL;
  89     }
  90
  91 }
  92
  93
  94 /******************************************************************
  95 * Name: ~FGMultiplayRxMgr
  96 * Description: Destructor. Closes and deletes objects owned by
  97 * this object.
  98 ******************************************************************/
  99 FGMultiplayRxMgr::~FGMultiplayRxMgr() {
 100
 101     Close();
 102
 103 }
 104
 105
 106 /******************************************************************
 107 * Name: init
 108 * Description: Initialises multiplayer receive.
 109 ******************************************************************/
 110 bool FGMultiplayRxMgr::init(void) {
 111
 112     bool bSuccess = true;                       // Result of initialisation
 113
 114     // Initialise object if not already done
 115     if (!m_bInitialised) {
 116
 117         // Set members from property values
 118         m_sCallsign = fgGetString("/sim/multiplay/callsign");
 119         m_sRxAddress = fgGetString("/sim/multiplay/rxhost");
 120         m_iRxPort = fgGetInt("/sim/multiplay/rxport");
 121
 122         cout << "FGMultiplayRxMgr::init - rxaddress= " << m_sRxAddress << endl;
 123         cout << "FGMultiplayRxMgr::init - rxport= " << m_iRxPort << endl;
 124         cout << "FGMultiplayRxMgr::init - callsign= " << m_sCallsign << endl;
 125
 126         // Create and open rx socket
 127         mDataRxSocket = new netSocket();
 128         if (!mDataRxSocket->open(false)) {
 129             // Failed to open rx socket
 130             cerr << "FGMultiplayRxMgr::Open - Failed to create data receive socket" << endl;
 131             bSuccess = false;
 132         } else {
 133
 134             // Configure the socket
 135             mDataRxSocket->setBlocking(false);
 136             mDataRxSocket->setBroadcast(true);
 137             if (mDataRxSocket->bind(m_sRxAddress.c_str(), m_iRxPort) != 0) {
 138                 perror("bind");
 139                 // Failed to bind
 140                 cerr << "FGMultiplayRxMgr::Open - Failed to bind receive socket" << endl;
 141                 bSuccess = false;
 142             }
 143
 144         }
 145
 146         // Save manager state
 147         m_bInitialised = bSuccess;
 148
 149     } else {
 150         cerr << "FGMultiplayRxMgr::OpenRx - Receiver open requested when receiver is already open" << endl;
 151         bSuccess = false;
 152     }
 153
 154     /* Return true if open succeeds */
 155     return bSuccess;
 156
 157 }
 158
 159
 160 /******************************************************************
 161 * Name: Close
 162 * Description: Closes and deletes and player connections. Closes
 163 * and deletes the rx socket. Resets the object state
 164 * to unitialised.
 165 ******************************************************************/
 166 void FGMultiplayRxMgr::Close(void) {
 167
 168     int iPlayerCnt;         // Count of players in player array
 169
 170     // Delete any existing players
 171     for (iPlayerCnt = 0; iPlayerCnt < MAX_PLAYERS; iPlayerCnt++) {
 172         if (m_Player[iPlayerCnt] != NULL) {
 173             delete m_Player[iPlayerCnt];
 174             m_Player[iPlayerCnt] = NULL;
 175         }
 176     }
 177
 178     // Delete socket
 179     if (mDataRxSocket) {
 180         mDataRxSocket->close();
 181         delete mDataRxSocket;
 182         mDataRxSocket = NULL;
 183     }
 184
 185     m_bInitialised = false;
 186
 187 }
 188
 189
 190 /******************************************************************
 191 * Name: ProcessData
 192 * Description: Processes data waiting at the receive socket. The
 193 * processing ends when there is no more data at the socket.
 194 ******************************************************************/
 195 void FGMultiplayRxMgr::ProcessData(void) {
 196
 197     char sMsg[MAX_PACKET_SIZE];         // Buffer for received message
 198     int iBytes;                         // Bytes received
 199     T_MsgHdr *MsgHdr;                   // Pointer to header in received data
 200     T_ChatMsg *ChatMsg;                 // Pointer to chat message in received data
 201     T_PositionMsg *PosMsg;              // Pointer to position message in received data
 202     char *sIpAddress;                   // Address information from header
 203     char *sModelName;                   // Model that the remote player is using
 204     char *sCallsign;                    // Callsign of the remote player
 205     struct in_addr PlayerAddress;       // Used for converting the player's address into dot notation
 206     int iPlayerCnt;                     // Count of players in player array
 207     bool bActivePlayer = false;         // The state of the player that sent the data
 208     int iPort;                          // Port that the remote player receives on
 209
 210
 211     if (m_bInitialised) {
 212
 213         // Read the receive socket and process any data
 214         do {
 215
 216             // Although the recv call asks for MAX_PACKET_SIZE of data,
 217             // the number of bytes returned will only be that of the next
 218             // packet waiting to be processed.
 219             iBytes = mDataRxSocket->recv(sMsg, MAX_PACKET_SIZE, 0);
 220
 221             // Data received
 222             if (iBytes > 0) {
 223                 if (iBytes >= sizeof(MsgHdr)) {
 224
 225                     // Read header
 226                     MsgHdr = (T_MsgHdr *)sMsg;
 227                     PlayerAddress.s_addr = MsgHdr->lReplyAddress;
 228                     sIpAddress = inet_ntoa(PlayerAddress);
 229                     iPort = MsgHdr->iReplyPort;
 230                     sCallsign = MsgHdr->sCallsign;
 231
 232                     // Process the player data unless we generated it
 233                     if (m_sCallsign != string(MsgHdr->sCallsign)) {
 234
 235
 236                         // Process messages
 237                         switch(MsgHdr->MsgId) {
 238                             case CHAT_MSG_ID:
 239                                 if (MsgHdr->iMsgLen == sizeof(T_MsgHdr) + sizeof(T_ChatMsg)) {
 240                                     ChatMsg = (T_ChatMsg *)(sMsg + sizeof(T_MsgHdr));
 241                                     cout << "Chat [" << MsgHdr->sCallsign << "]" << " " << ChatMsg->sText << endl;
 242                                 } else {
 243                                     cerr << "FGMultiplayRxMgr::MP_ProcessData - Chat message received with insufficient data" << endl;
 244                                 }
 245                                 break;
 246
 247                             case POS_DATA_ID:
 248                                 if (MsgHdr->iMsgLen == sizeof(T_MsgHdr) + sizeof(T_PositionMsg)) {
 249                                     PosMsg = (T_PositionMsg *)(sMsg + sizeof(T_MsgHdr));
 250                                     sModelName = PosMsg->sModel;
 251
 252                                     // Check if the player is already in the game by using the Callsign.
 253                                     bActivePlayer = false;
 254                                     for (iPlayerCnt = 0; iPlayerCnt < MAX_PLAYERS; iPlayerCnt++) {
 255                                         if (m_Player[iPlayerCnt] != NULL) {
 256                                             if (m_Player[iPlayerCnt]->CompareCallsign(MsgHdr->sCallsign)) {
 257
 258                                                 // Player found. Update the data for the player.
 259                                                 m_Player[iPlayerCnt]->SetPosition(PosMsg->PlayerPos);
 260                                                 bActivePlayer = true;
 261
 262                                             }
 263                                         }
 264                                     }
 265
 266                                     // Player not active, so add as new player
 267                                     if (!bActivePlayer) {
 268                                         iPlayerCnt = 0;
 269                                         do {
 270                                             if (m_Player[iPlayerCnt] == NULL) {
 271                                                 cout << "FGMultiplayRxMgr::ProcessRxData - Add new player. IP: " << sIpAddress
 272                                                     << ", Call: " <<  sCallsign << ", model: " << sModelName << endl;
 273                                                 m_Player[iPlayerCnt] = new MPPlayer;
 274                                                 m_Player[iPlayerCnt]->Open(string(sIpAddress), iPort, string(sCallsign), string(sModelName), false);
 275                                                 m_Player[iPlayerCnt]->SetPosition(PosMsg->PlayerPos);
 276                                                 bActivePlayer = true;
 277                                             }
 278                                             iPlayerCnt++;
 279                                         } while (iPlayerCnt < MAX_PLAYERS && !bActivePlayer);
 280
 281                                         // Check if the player was added
 282                                         if (!bActivePlayer) {
 283                                             if (iPlayerCnt == MAX_PLAYERS) {
 284                                                 cerr << "FGMultiplayRxMgr::MP_ProcessData - Unable to add new player (" << sCallsign << "). Too many players." << endl;
 285                                             }
 286                                         }
 287                                     }
 288
 289                                 } else {
 290                                     cerr << "FGMultiplayRxMgr::MP_ProcessData - Position message received with insufficient data" << endl;
 291                                 }
 292                                 break;
 293
 294                             default:
 295                                 cerr << "FGMultiplayRxMgr::MP_ProcessData - Unknown message Id received: " << MsgHdr->MsgId << endl;
 296                                 break;
 297
 298
 299                         }
 300                     }
 301                 }
 302
 303
 304             // Error or no data
 305             } else if (iBytes == -1) {
 306                 if (errno != EAGAIN) {
 307                     perror("FGMultiplayRxMgr::MP_ProcessData");
 308                 }
 309             }
 310
 311         } while (iBytes > 0);
 312
 313     }
 314
 315
 316 }
 317
 318
 319 /******************************************************************
 320 * Name: Update
 321 * Description: For each active player, tell the player object
 322 * to update its position on the scene. If a player object
 323 * returns status information indicating that it has not
 324 * had an update for some time then the player is deleted.
 325 ******************************************************************/
 326 void FGMultiplayRxMgr::Update(void) {
 327
 328     int iPlayerDataState;
 329     int iPlayerId;
 330
 331     for (iPlayerId = 0; iPlayerId < MAX_PLAYERS; iPlayerId++) {
 332         if (m_Player[iPlayerId] != NULL) {
 333             iPlayerDataState = m_Player[iPlayerId]->Draw();
 334
 335             // If the player has not received an update for some
 336             // time then assume that the player has quit.
 337             if (iPlayerDataState == PLAYER_DATA_EXPIRED) {
 338                 delete m_Player[iPlayerId];
 339                 m_Player[iPlayerId] = NULL;
 340             }
 341
 342         }
 343     }
 344
 345 }
 346
 347