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/socket.h>
  54 #include <netinet/in.h>
  55 #include <arpa/inet.h>
  56 #include <plib/netSocket.h>
  57 #include <stdlib.h>
  58 #include <Main/fg_props.hxx>
  59
  60 #include "multiplayrxmgr.hxx"
  61 #include "mpmessages.hxx"
  62 #include "mpplayer.hxx"
  63
  64 #define MAX_PACKET_SIZE 1024
  65
  66 // These constants are provided so that the ident command can list file versions.
  67 const char sMULTIPLAYTXMGR_BID[] = "$Id$";
  68 const char sMULTIPLAYRXMGR_HID[] = MULTIPLAYRXMGR_HID;
  69
  70
  71
  72 /******************************************************************
  73 * Name: FGMultiplayRxMgr
  74 * Description: Constructor.
  75 ******************************************************************/
  76 FGMultiplayRxMgr::FGMultiplayRxMgr() {
  77
  78     int iPlayerCnt;         // Count of players in player array
  79
  80     // Initialise private members
  81     m_sRxAddress = "0";
  82     m_iRxPort = 0;
  83     m_bInitialised = false;
  84
  85     // Clear the player array
  86     for (iPlayerCnt = 0; iPlayerCnt < MAX_PLAYERS; iPlayerCnt++) {
  87         m_Player[iPlayerCnt] = NULL;
  88     }
  89
  90 }
  91
  92
  93 /******************************************************************
  94 * Name: ~FGMultiplayRxMgr
  95 * Description: Destructor. Closes and deletes objects owned by
  96 * this object.
  97 ******************************************************************/
  98 FGMultiplayRxMgr::~FGMultiplayRxMgr() {
  99
 100     Close();
 101
 102 }
 103
 104
 105 /******************************************************************
 106 * Name: init
 107 * Description: Initialises multiplayer receive.
 108 ******************************************************************/
 109 bool FGMultiplayRxMgr::init(void) {
 110
 111     bool bSuccess = true;                       // Result of initialisation
 112
 113     // Initialise object if not already done
 114     if (!m_bInitialised) {
 115
 116         // Set members from property values
 117         m_sCallsign = fgGetString("/sim/multiplay/callsign");
 118         m_sRxAddress = fgGetString("/sim/multiplay/rxhost");
 119         m_iRxPort = fgGetInt("/sim/multiplay/rxport");
 120
 121         cout << "FGMultiplayRxMgr::init - rxaddress= " << m_sRxAddress << endl;
 122         cout << "FGMultiplayRxMgr::init - rxport= " << m_iRxPort << endl;
 123         cout << "FGMultiplayRxMgr::init - callsign= " << m_sCallsign << endl;
 124
 125         // Create and open rx socket
 126         mDataRxSocket = new netSocket();
 127         if (!mDataRxSocket->open(false)) {
 128             // Failed to open rx socket
 129             cerr << "FGMultiplayRxMgr::Open - Failed to create data receive socket" << endl;
 130             bSuccess = false;
 131         } else {
 132
 133             // Configure the socket
 134             mDataRxSocket->setBlocking(false);
 135             mDataRxSocket->setBroadcast(true);
 136             if (mDataRxSocket->bind(m_sRxAddress.c_str(), m_iRxPort) != 0) {
 137                 perror("bind");
 138                 // Failed to bind
 139                 cerr << "FGMultiplayRxMgr::Open - Failed to bind receive socket" << endl;
 140                 bSuccess = false;
 141             }
 142
 143         }
 144
 145         // Save manager state
 146         m_bInitialised = bSuccess;
 147
 148     } else {
 149         cerr << "FGMultiplayRxMgr::OpenRx - Receiver open requested when receiver is already open" << endl;
 150         bSuccess = false;
 151     }
 152
 153     /* Return true if open succeeds */
 154     return bSuccess;
 155
 156 }
 157
 158
 159 /******************************************************************
 160 * Name: Close
 161 * Description: Closes and deletes and player connections. Closes
 162 * and deletes the rx socket. Resets the object state
 163 * to unitialised.
 164 ******************************************************************/
 165 void FGMultiplayRxMgr::Close(void) {
 166
 167     int iPlayerCnt;         // Count of players in player array
 168
 169     // Delete any existing players
 170     for (iPlayerCnt = 0; iPlayerCnt < MAX_PLAYERS; iPlayerCnt++) {
 171         if (m_Player[iPlayerCnt] != NULL) {
 172             delete m_Player[iPlayerCnt];
 173             m_Player[iPlayerCnt] = NULL;
 174         }
 175     }
 176
 177     // Delete socket
 178     if (mDataRxSocket) {
 179         mDataRxSocket->close();
 180         delete mDataRxSocket;
 181         mDataRxSocket = NULL;
 182     }
 183
 184     m_bInitialised = false;
 185
 186 }
 187
 188
 189 /******************************************************************
 190 * Name: ProcessData
 191 * Description: Processes data waiting at the receive socket. The
 192 * processing ends when there is no more data at the socket.
 193 ******************************************************************/
 194 void FGMultiplayRxMgr::ProcessData(void) {
 195
 196     char sMsg[MAX_PACKET_SIZE];         // Buffer for received message
 197     int iBytes;                         // Bytes received
 198     T_MsgHdr *MsgHdr;                   // Pointer to header in received data
 199     T_ChatMsg *ChatMsg;                 // Pointer to chat message in received data
 200     T_PositionMsg *PosMsg;              // Pointer to position message in received data
 201     char *sIpAddress;                   // Address information from header
 202     char *sModelName;                   // Model that the remote player is using
 203     char *sCallsign;                    // Callsign of the remote player
 204     struct in_addr PlayerAddress;       // Used for converting the player's address into dot notation
 205     int iPlayerCnt;                     // Count of players in player array
 206     bool bActivePlayer = false;         // The state of the player that sent the data
 207     int iPort;                          // Port that the remote player receives on
 208
 209
 210     if (m_bInitialised) {
 211
 212         // Read the receive socket and process any data
 213         do {
 214
 215             // Although the recv call asks for MAX_PACKET_SIZE of data,
 216             // the number of bytes returned will only be that of the next
 217             // packet waiting to be processed.
 218             iBytes = mDataRxSocket->recv(sMsg, MAX_PACKET_SIZE, 0);
 219
 220             // Data received
 221             if (iBytes > 0) {
 222                 if (iBytes >= sizeof(MsgHdr)) {
 223
 224                     // Read header
 225                     MsgHdr = (T_MsgHdr *)sMsg;
 226                     PlayerAddress.s_addr = MsgHdr->lReplyAddress;
 227                     sIpAddress = inet_ntoa(PlayerAddress);
 228                     iPort = MsgHdr->iReplyPort;
 229                     sCallsign = MsgHdr->sCallsign;
 230
 231                     // Process the player data unless we generated it
 232                     if (m_sCallsign != string(MsgHdr->sCallsign)) {
 233
 234
 235                         // Process messages
 236                         switch(MsgHdr->MsgId) {
 237                             case CHAT_MSG_ID:
 238                                 if (MsgHdr->iMsgLen == sizeof(T_MsgHdr) + sizeof(T_ChatMsg)) {
 239                                     ChatMsg = (T_ChatMsg *)(sMsg + sizeof(T_MsgHdr));
 240                                     cout << "Chat [" << MsgHdr->sCallsign << "]" << " " << ChatMsg->sText << endl;
 241                                 } else {
 242                                     cerr << "FGMultiplayRxMgr::MP_ProcessData - Chat message received with insufficient data" << endl;
 243                                 }
 244                                 break;
 245
 246                             case POS_DATA_ID:
 247                                 if (MsgHdr->iMsgLen == sizeof(T_MsgHdr) + sizeof(T_PositionMsg)) {
 248                                     PosMsg = (T_PositionMsg *)(sMsg + sizeof(T_MsgHdr));
 249                                     sModelName = PosMsg->sModel;
 250
 251                                     // Check if the player is already in the game by using the Callsign.
 252                                     bActivePlayer = false;
 253                                     for (iPlayerCnt = 0; iPlayerCnt < MAX_PLAYERS; iPlayerCnt++) {
 254                                         if (m_Player[iPlayerCnt] != NULL) {
 255                                             if (m_Player[iPlayerCnt]->CompareCallsign(MsgHdr->sCallsign)) {
 256
 257                                                 // Player found. Update the data for the player.
 258                                                 m_Player[iPlayerCnt]->SetPosition(PosMsg->PlayerPos);
 259                                                 bActivePlayer = true;
 260
 261                                             }
 262                                         }
 263                                     }
 264
 265                                     // Player not active, so add as new player
 266                                     if (!bActivePlayer) {
 267                                         iPlayerCnt = 0;
 268                                         do {
 269                                             if (m_Player[iPlayerCnt] == NULL) {
 270                                                 cout << "FGMultiplayRxMgr::ProcessRxData - Add new player. IP: " << sIpAddress
 271                                                     << ", Call: " <<  sCallsign << ", model: " << sModelName << endl;
 272                                                 m_Player[iPlayerCnt] = new MPPlayer;
 273                                                 m_Player[iPlayerCnt]->Open(string(sIpAddress), iPort, string(sCallsign), string(sModelName), false);
 274                                                 m_Player[iPlayerCnt]->SetPosition(PosMsg->PlayerPos);
 275                                                 bActivePlayer = true;
 276                                             }
 277                                             iPlayerCnt++;
 278                                         } while (iPlayerCnt < MAX_PLAYERS && !bActivePlayer);
 279
 280                                         // Check if the player was added
 281                                         if (!bActivePlayer) {
 282                                             if (iPlayerCnt == MAX_PLAYERS) {
 283                                                 cerr << "FGMultiplayRxMgr::MP_ProcessData - Unable to add new player (" << sCallsign << "). Too many players." << endl;
 284                                             }
 285                                         }
 286                                     }
 287
 288                                 } else {
 289                                     cerr << "FGMultiplayRxMgr::MP_ProcessData - Position message received with insufficient data" << endl;
 290                                 }
 291                                 break;
 292
 293                             default:
 294                                 cerr << "FGMultiplayRxMgr::MP_ProcessData - Unknown message Id received: " << MsgHdr->MsgId << endl;
 295                                 break;
 296
 297
 298                         }
 299                     }
 300                 }
 301
 302
 303             // Error or no data
 304             } else if (iBytes == -1) {
 305                 if (errno != EAGAIN) {
 306                     perror("FGMultiplayRxMgr::MP_ProcessData");
 307                 }
 308             }
 309
 310         } while (iBytes > 0);
 311
 312     }
 313
 314
 315 }
 316
 317
 318 /******************************************************************
 319 * Name: Update
 320 * Description: For each active player, tell the player object
 321 * to update its position on the scene. If a player object
 322 * returns status information indicating that it has not
 323 * had an update for some time then the player is deleted.
 324 ******************************************************************/
 325 void FGMultiplayRxMgr::Update(void) {
 326
 327     int iPlayerDataState;
 328     int iPlayerId;
 329
 330     for (iPlayerId = 0; iPlayerId < MAX_PLAYERS; iPlayerId++) {
 331         if (m_Player[iPlayerId] != NULL) {
 332             iPlayerDataState = m_Player[iPlayerId]->Draw();
 333
 334             // If the player has not received an update for some
 335             // time then assume that the player has quit.
 336             if (iPlayerDataState == PLAYER_DATA_EXPIRED) {
 337                 delete m_Player[iPlayerId];
 338                 m_Player[iPlayerId] = NULL;
 339             }
 340
 341         }
 342     }
 343
 344 }
 345
 346