src/MultiPlayer/multiplaymgr.cxx

   1 //////////////////////////////////////////////////////////////////////
   2 //
   3 // multiplaymgr.hpp
   4 //
   5 // Written by Duncan McCreanor, started February 2003.
   6 // duncan.mccreanor@airservicesaustralia.com
   7 //
   8 // Copyright (C) 2003  Airservices Australia
   9 // Copyright (C) 2005  Oliver Schroeder
  10 // Copyright (C) 2006  Mathias Froehlich
  11 //
  12 // This program is free software; you can redistribute it and/or
  13 // modify it under the terms of the GNU General Public License as
  14 // published by the Free Software Foundation; either version 2 of the
  15 // License, or (at your option) any later version.
  16 //
  17 // This program is distributed in the hope that it will be useful, but
  18 // WITHOUT ANY WARRANTY; without even the implied warranty of
  19 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  20 // General Public License for more details.
  21 //
  22 // You should have received a copy of the GNU General Public License
  23 // along with this program; if not, write to the Free Software
  24 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  25 //
  26 // $Id$
  27 //
  28 //////////////////////////////////////////////////////////////////////
  29
  30 #ifdef HAVE_CONFIG_H
  31 #include <config.h>
  32 #endif
  33
  34 #include <iostream>
  35 #include <algorithm>
  36 #include <osg/Math>             // isNaN
  37 #include <plib/netSocket.h>
  38
  39 #include <simgear/misc/stdint.hxx>
  40 #include <simgear/timing/timestamp.hxx>
  41 #include <simgear/debug/logstream.hxx>
  42 #include <simgear/props/props.hxx>
  43
  44 #include <AIModel/AIManager.hxx>
  45 #include <Main/fg_props.hxx>
  46 #include "multiplaymgr.hxx"
  47 #include "mpmessages.hxx"
  48
  49 using std::cerr;
  50
  51 #define MAX_PACKET_SIZE 1200
  52 #define MAX_TEXT_SIZE 128
  53
  54 // These constants are provided so that the ident
  55 // command can list file versions
  56 const char sMULTIPLAYMGR_BID[] = "$Id$";
  57 const char sMULTIPLAYMGR_HID[] = MULTIPLAYTXMGR_HID;
  58
  59 // A static map of protocol property id values to property paths,
  60 // This should be extendable dynamically for every specific aircraft ...
  61 // For now only that static list
  62 FGMultiplayMgr::IdPropertyList
  63 const FGMultiplayMgr::sIdPropertyList[] = {
  64   {100, "surface-positions/left-aileron-pos-norm",  SGPropertyNode::FLOAT},
  65   {101, "surface-positions/right-aileron-pos-norm", SGPropertyNode::FLOAT},
  66   {102, "surface-positions/elevator-pos-norm",      SGPropertyNode::FLOAT},
  67   {103, "surface-positions/rudder-pos-norm",        SGPropertyNode::FLOAT},
  68   {104, "surface-positions/flap-pos-norm",          SGPropertyNode::FLOAT},
  69   {105, "surface-positions/speedbrake-pos-norm",    SGPropertyNode::FLOAT},
  70   {106, "gear/tailhook/position-norm",              SGPropertyNode::FLOAT},
  71   {107, "gear/launchbar/position-norm",             SGPropertyNode::FLOAT},
  72   {108, "gear/launchbar/state",                     SGPropertyNode::STRING},
  73   {109, "gear/launchbar/holdback-position-norm",    SGPropertyNode::FLOAT},
  74   {110, "canopy/position-norm",                     SGPropertyNode::FLOAT},
  75   {111, "surface-positions/wing-pos-norm",          SGPropertyNode::FLOAT},
  76   {112, "surface-positions/wing-fold-pos-norm",     SGPropertyNode::FLOAT},
  77
  78   {200, "gear/gear[0]/compression-norm",           SGPropertyNode::FLOAT},
  79   {201, "gear/gear[0]/position-norm",              SGPropertyNode::FLOAT},
  80   {210, "gear/gear[1]/compression-norm",           SGPropertyNode::FLOAT},
  81   {211, "gear/gear[1]/position-norm",              SGPropertyNode::FLOAT},
  82   {220, "gear/gear[2]/compression-norm",           SGPropertyNode::FLOAT},
  83   {221, "gear/gear[2]/position-norm",              SGPropertyNode::FLOAT},
  84   {230, "gear/gear[3]/compression-norm",           SGPropertyNode::FLOAT},
  85   {231, "gear/gear[3]/position-norm",              SGPropertyNode::FLOAT},
  86   {240, "gear/gear[4]/compression-norm",           SGPropertyNode::FLOAT},
  87   {241, "gear/gear[4]/position-norm",              SGPropertyNode::FLOAT},
  88
  89   {300, "engines/engine[0]/n1",  SGPropertyNode::FLOAT},
  90   {301, "engines/engine[0]/n2",  SGPropertyNode::FLOAT},
  91   {302, "engines/engine[0]/rpm", SGPropertyNode::FLOAT},
  92   {310, "engines/engine[1]/n1",  SGPropertyNode::FLOAT},
  93   {311, "engines/engine[1]/n2",  SGPropertyNode::FLOAT},
  94   {312, "engines/engine[1]/rpm", SGPropertyNode::FLOAT},
  95   {320, "engines/engine[2]/n1",  SGPropertyNode::FLOAT},
  96   {321, "engines/engine[2]/n2",  SGPropertyNode::FLOAT},
  97   {322, "engines/engine[2]/rpm", SGPropertyNode::FLOAT},
  98   {330, "engines/engine[3]/n1",  SGPropertyNode::FLOAT},
  99   {331, "engines/engine[3]/n2",  SGPropertyNode::FLOAT},
 100   {332, "engines/engine[3]/rpm", SGPropertyNode::FLOAT},
 101   {340, "engines/engine[4]/n1",  SGPropertyNode::FLOAT},
 102   {341, "engines/engine[4]/n2",  SGPropertyNode::FLOAT},
 103   {342, "engines/engine[4]/rpm", SGPropertyNode::FLOAT},
 104   {350, "engines/engine[5]/n1",  SGPropertyNode::FLOAT},
 105   {351, "engines/engine[5]/n2",  SGPropertyNode::FLOAT},
 106   {352, "engines/engine[5]/rpm", SGPropertyNode::FLOAT},
 107   {360, "engines/engine[6]/n1",  SGPropertyNode::FLOAT},
 108   {361, "engines/engine[6]/n2",  SGPropertyNode::FLOAT},
 109   {362, "engines/engine[6]/rpm", SGPropertyNode::FLOAT},
 110   {370, "engines/engine[7]/n1",  SGPropertyNode::FLOAT},
 111   {371, "engines/engine[7]/n2",  SGPropertyNode::FLOAT},
 112   {372, "engines/engine[7]/rpm", SGPropertyNode::FLOAT},
 113   {380, "engines/engine[8]/n1",  SGPropertyNode::FLOAT},
 114   {381, "engines/engine[8]/n2",  SGPropertyNode::FLOAT},
 115   {382, "engines/engine[8]/rpm", SGPropertyNode::FLOAT},
 116   {390, "engines/engine[9]/n1",  SGPropertyNode::FLOAT},
 117   {391, "engines/engine[9]/n2",  SGPropertyNode::FLOAT},
 118   {392, "engines/engine[9]/rpm", SGPropertyNode::FLOAT},
 119
 120   {800, "rotors/main/rpm", SGPropertyNode::FLOAT},
 121   {801, "rotors/tail/rpm", SGPropertyNode::FLOAT},
 122   {810, "rotors/main/blade[0]/position-deg",  SGPropertyNode::FLOAT},
 123   {811, "rotors/main/blade[1]/position-deg",  SGPropertyNode::FLOAT},
 124   {812, "rotors/main/blade[2]/position-deg",  SGPropertyNode::FLOAT},
 125   {813, "rotors/main/blade[3]/position-deg",  SGPropertyNode::FLOAT},
 126   {820, "rotors/main/blade[0]/flap-deg",  SGPropertyNode::FLOAT},
 127   {821, "rotors/main/blade[1]/flap-deg",  SGPropertyNode::FLOAT},
 128   {822, "rotors/main/blade[2]/flap-deg",  SGPropertyNode::FLOAT},
 129   {823, "rotors/main/blade[3]/flap-deg",  SGPropertyNode::FLOAT},
 130   {830, "rotors/tail/blade[0]/position-deg",  SGPropertyNode::FLOAT},
 131   {831, "rotors/tail/blade[1]/position-deg",  SGPropertyNode::FLOAT},
 132
 133   {900, "sim/hitches/aerotow/tow/length",                       SGPropertyNode::FLOAT},
 134   {901, "sim/hitches/aerotow/tow/elastic-constant",             SGPropertyNode::FLOAT},
 135   {902, "sim/hitches/aerotow/tow/weight-per-m-kg-m",            SGPropertyNode::FLOAT},
 136   {903, "sim/hitches/aerotow/tow/dist",                         SGPropertyNode::FLOAT},
 137   {904, "sim/hitches/aerotow/tow/connected-to-property-node",   SGPropertyNode::BOOL},
 138   {905, "sim/hitches/aerotow/tow/connected-to-ai-or-mp-callsign",   SGPropertyNode::STRING},
 139   {906, "sim/hitches/aerotow/tow/brake-force",                  SGPropertyNode::FLOAT},
 140   {907, "sim/hitches/aerotow/tow/end-force-x",                  SGPropertyNode::FLOAT},
 141   {908, "sim/hitches/aerotow/tow/end-force-y",                  SGPropertyNode::FLOAT},
 142   {909, "sim/hitches/aerotow/tow/end-force-z",                  SGPropertyNode::FLOAT},
 143   {930, "sim/hitches/aerotow/is-slave",                         SGPropertyNode::BOOL},
 144   {931, "sim/hitches/aerotow/speed-in-tow-direction",           SGPropertyNode::FLOAT},
 145   {932, "sim/hitches/aerotow/open",                             SGPropertyNode::BOOL},
 146   {933, "sim/hitches/aerotow/local-pos-x",                      SGPropertyNode::FLOAT},
 147   {934, "sim/hitches/aerotow/local-pos-y",                      SGPropertyNode::FLOAT},
 148   {935, "sim/hitches/aerotow/local-pos-z",                      SGPropertyNode::FLOAT},
 149
 150   {1001, "controls/flight/slats",  SGPropertyNode::FLOAT},
 151   {1002, "controls/flight/speedbrake",  SGPropertyNode::FLOAT},
 152   {1003, "controls/flight/spoilers",  SGPropertyNode::FLOAT},
 153   {1004, "controls/gear/gear-down",  SGPropertyNode::FLOAT},
 154   {1005, "controls/lighting/nav-lights",  SGPropertyNode::FLOAT},
 155   {1006, "controls/armament/station[0]/jettison-all",  SGPropertyNode::BOOL},
 156
 157   {1100, "sim/model/variant", SGPropertyNode::INT},
 158   {1101, "sim/model/livery/file", SGPropertyNode::STRING},
 159
 160   {10001, "sim/multiplay/transmission-freq-hz",  SGPropertyNode::STRING},
 161   {10002, "sim/multiplay/chat",  SGPropertyNode::STRING},
 162
 163   {10100, "sim/multiplay/generic/string[0]", SGPropertyNode::STRING},
 164   {10101, "sim/multiplay/generic/string[1]", SGPropertyNode::STRING},
 165   {10102, "sim/multiplay/generic/string[2]", SGPropertyNode::STRING},
 166   {10103, "sim/multiplay/generic/string[3]", SGPropertyNode::STRING},
 167   {10104, "sim/multiplay/generic/string[4]", SGPropertyNode::STRING},
 168   {10105, "sim/multiplay/generic/string[5]", SGPropertyNode::STRING},
 169   {10106, "sim/multiplay/generic/string[6]", SGPropertyNode::STRING},
 170   {10107, "sim/multiplay/generic/string[7]", SGPropertyNode::STRING},
 171   {10108, "sim/multiplay/generic/string[8]", SGPropertyNode::STRING},
 172   {10109, "sim/multiplay/generic/string[9]", SGPropertyNode::STRING},
 173   {10110, "sim/multiplay/generic/string[10]", SGPropertyNode::STRING},
 174   {10111, "sim/multiplay/generic/string[11]", SGPropertyNode::STRING},
 175   {10112, "sim/multiplay/generic/string[12]", SGPropertyNode::STRING},
 176   {10113, "sim/multiplay/generic/string[13]", SGPropertyNode::STRING},
 177   {10114, "sim/multiplay/generic/string[14]", SGPropertyNode::STRING},
 178   {10115, "sim/multiplay/generic/string[15]", SGPropertyNode::STRING},
 179   {10116, "sim/multiplay/generic/string[16]", SGPropertyNode::STRING},
 180   {10117, "sim/multiplay/generic/string[17]", SGPropertyNode::STRING},
 181   {10118, "sim/multiplay/generic/string[18]", SGPropertyNode::STRING},
 182   {10119, "sim/multiplay/generic/string[19]", SGPropertyNode::STRING},
 183
 184   {10200, "sim/multiplay/generic/float[0]", SGPropertyNode::FLOAT},
 185   {10201, "sim/multiplay/generic/float[1]", SGPropertyNode::FLOAT},
 186   {10202, "sim/multiplay/generic/float[2]", SGPropertyNode::FLOAT},
 187   {10203, "sim/multiplay/generic/float[3]", SGPropertyNode::FLOAT},
 188   {10204, "sim/multiplay/generic/float[4]", SGPropertyNode::FLOAT},
 189   {10205, "sim/multiplay/generic/float[5]", SGPropertyNode::FLOAT},
 190   {10206, "sim/multiplay/generic/float[6]", SGPropertyNode::FLOAT},
 191   {10207, "sim/multiplay/generic/float[7]", SGPropertyNode::FLOAT},
 192   {10208, "sim/multiplay/generic/float[8]", SGPropertyNode::FLOAT},
 193   {10209, "sim/multiplay/generic/float[9]", SGPropertyNode::FLOAT},
 194   {10210, "sim/multiplay/generic/float[10]", SGPropertyNode::FLOAT},
 195   {10211, "sim/multiplay/generic/float[11]", SGPropertyNode::FLOAT},
 196   {10212, "sim/multiplay/generic/float[12]", SGPropertyNode::FLOAT},
 197   {10213, "sim/multiplay/generic/float[13]", SGPropertyNode::FLOAT},
 198   {10214, "sim/multiplay/generic/float[14]", SGPropertyNode::FLOAT},
 199   {10215, "sim/multiplay/generic/float[15]", SGPropertyNode::FLOAT},
 200   {10216, "sim/multiplay/generic/float[16]", SGPropertyNode::FLOAT},
 201   {10217, "sim/multiplay/generic/float[17]", SGPropertyNode::FLOAT},
 202   {10218, "sim/multiplay/generic/float[18]", SGPropertyNode::FLOAT},
 203   {10219, "sim/multiplay/generic/float[19]", SGPropertyNode::FLOAT},
 204
 205   {10300, "sim/multiplay/generic/int[0]", SGPropertyNode::INT},
 206   {10301, "sim/multiplay/generic/int[1]", SGPropertyNode::INT},
 207   {10302, "sim/multiplay/generic/int[2]", SGPropertyNode::INT},
 208   {10303, "sim/multiplay/generic/int[3]", SGPropertyNode::INT},
 209   {10304, "sim/multiplay/generic/int[4]", SGPropertyNode::INT},
 210   {10305, "sim/multiplay/generic/int[5]", SGPropertyNode::INT},
 211   {10306, "sim/multiplay/generic/int[6]", SGPropertyNode::INT},
 212   {10307, "sim/multiplay/generic/int[7]", SGPropertyNode::INT},
 213   {10308, "sim/multiplay/generic/int[8]", SGPropertyNode::INT},
 214   {10309, "sim/multiplay/generic/int[9]", SGPropertyNode::INT},
 215   {10310, "sim/multiplay/generic/int[10]", SGPropertyNode::INT},
 216   {10311, "sim/multiplay/generic/int[11]", SGPropertyNode::INT},
 217   {10312, "sim/multiplay/generic/int[12]", SGPropertyNode::INT},
 218   {10313, "sim/multiplay/generic/int[13]", SGPropertyNode::INT},
 219   {10314, "sim/multiplay/generic/int[14]", SGPropertyNode::INT},
 220   {10315, "sim/multiplay/generic/int[15]", SGPropertyNode::INT},
 221   {10316, "sim/multiplay/generic/int[16]", SGPropertyNode::INT},
 222   {10317, "sim/multiplay/generic/int[17]", SGPropertyNode::INT},
 223   {10318, "sim/multiplay/generic/int[18]", SGPropertyNode::INT},
 224   {10319, "sim/multiplay/generic/int[19]", SGPropertyNode::INT},
 225 };
 226
 227 const unsigned
 228 FGMultiplayMgr::numProperties = (sizeof(FGMultiplayMgr::sIdPropertyList)
 229                                  / sizeof(FGMultiplayMgr::sIdPropertyList[0]));
 230
 231 // Look up a property ID using binary search.
 232 namespace
 233 {
 234   struct ComparePropertyId
 235   {
 236     bool operator()(const FGMultiplayMgr::IdPropertyList& lhs,
 237                     const FGMultiplayMgr::IdPropertyList& rhs)
 238     {
 239       return lhs.id < rhs.id;
 240     }
 241     bool operator()(const FGMultiplayMgr::IdPropertyList& lhs,
 242                     unsigned id)
 243     {
 244       return lhs.id < id;
 245     }
 246     bool operator()(unsigned id,
 247                     const FGMultiplayMgr::IdPropertyList& rhs)
 248     {
 249       return id < rhs.id;
 250     }
 251   };
 252
 253 }
 254 const FGMultiplayMgr::IdPropertyList* FGMultiplayMgr::findProperty(unsigned id)
 255 {
 256   std::pair<const IdPropertyList*, const IdPropertyList*> result
 257     = std::equal_range(sIdPropertyList, sIdPropertyList + numProperties, id,
 258                        ComparePropertyId());
 259   if (result.first == result.second) {
 260     return 0;
 261   } else {
 262     return result.first;
 263   }
 264 }
 265
 266 namespace
 267 {
 268   bool verifyProperties(const xdr_data_t* data, const xdr_data_t* end)
 269   {
 270     const xdr_data_t* xdr = data;
 271     while (xdr < end) {
 272       unsigned id = XDR_decode_uint32(*xdr);
 273       const FGMultiplayMgr::IdPropertyList* plist
 274         = FGMultiplayMgr::findProperty(id);
 275
 276       if (plist) {
 277         xdr++;
 278         // How we decode the remainder of the property depends on the type
 279         switch (plist->type) {
 280         case SGPropertyNode::INT:
 281         case SGPropertyNode::BOOL:
 282         case SGPropertyNode::LONG:
 283           xdr++;
 284           break;
 285         case SGPropertyNode::FLOAT:
 286         case SGPropertyNode::DOUBLE:
 287           {
 288             float val = XDR_decode_float(*xdr);
 289             if (osg::isNaN(val))
 290               return false;
 291             xdr++;
 292             break;
 293           }
 294         case SGPropertyNode::STRING:
 295         case SGPropertyNode::UNSPECIFIED:
 296           {
 297             // String is complicated. It consists of
 298             // The length of the string
 299             // The string itself
 300             // Padding to the nearest 4-bytes.
 301             // XXX Yes, each byte is padded out to a word! Too late
 302             // to change...
 303             uint32_t length = XDR_decode_uint32(*xdr);
 304             xdr++;
 305             // Old versions truncated the string but left the length
 306             // unadjusted.
 307             if (length > MAX_TEXT_SIZE)
 308               length = MAX_TEXT_SIZE;
 309             xdr += length;
 310             // Now handle the padding
 311             while ((length % 4) != 0)
 312               {
 313                 xdr++;
 314                 length++;
 315                 //cout << "0";
 316               }
 317           }
 318           break;
 319         default:
 320           // cerr << "Unknown Prop type " << id << " " << type << "\n";
 321           xdr++;
 322           break;
 323         }
 324       }
 325       else {
 326         // give up; this is a malformed property list.
 327         return false;
 328       }
 329     }
 330     return true;
 331   }
 332 }
 333 //////////////////////////////////////////////////////////////////////
 334 //
 335 //  MultiplayMgr constructor
 336 //
 337 //////////////////////////////////////////////////////////////////////
 338 FGMultiplayMgr::FGMultiplayMgr()
 339 {
 340   mSocket        = 0;
 341   mInitialised   = false;
 342   mHaveServer    = false;
 343 } // FGMultiplayMgr::FGMultiplayMgr()
 344 //////////////////////////////////////////////////////////////////////
 345
 346 //////////////////////////////////////////////////////////////////////
 347 //
 348 //  MultiplayMgr destructor
 349 //
 350 //////////////////////////////////////////////////////////////////////
 351 FGMultiplayMgr::~FGMultiplayMgr()
 352 {
 353   Close();
 354 } // FGMultiplayMgr::~FGMultiplayMgr()
 355 //////////////////////////////////////////////////////////////////////
 356
 357 //////////////////////////////////////////////////////////////////////
 358 //
 359 //  Initialise object
 360 //
 361 //////////////////////////////////////////////////////////////////////
 362 bool
 363 FGMultiplayMgr::init (void)
 364 {
 365   //////////////////////////////////////////////////
 366   //  Initialise object if not already done
 367   //////////////////////////////////////////////////
 368   if (mInitialised) {
 369     SG_LOG(SG_NETWORK, SG_WARN, "FGMultiplayMgr::init - already initialised");
 370     return false;
 371   }
 372   //////////////////////////////////////////////////
 373   //  Set members from property values
 374   //////////////////////////////////////////////////
 375   short rxPort = fgGetInt("/sim/multiplay/rxport");
 376   string rxAddress = fgGetString("/sim/multiplay/rxhost");
 377   short txPort = fgGetInt("/sim/multiplay/txport");
 378   string txAddress = fgGetString("/sim/multiplay/txhost");
 379   mCallsign = fgGetString("/sim/multiplay/callsign");
 380   if (txPort > 0 && !txAddress.empty()) {
 381     mServer.set(txAddress.c_str(), txPort);
 382     if (strncmp (mServer.getHost(), "0.0.0.0", 8) == 0) {
 383       mHaveServer = false;
 384       SG_LOG(SG_NETWORK, SG_ALERT,
 385         "FGMultiplayMgr - could not resolve '"
 386         << txAddress << "', Multiplayermode disabled");
 387     } else {
 388       mHaveServer = true;
 389     }
 390     if (rxPort <= 0)
 391       rxPort = txPort;
 392   }
 393   if (rxPort <= 0) {
 394     SG_LOG(SG_NETWORK, SG_ALERT,
 395       "FGMultiplayMgr - No receiver port, Multiplayermode disabled");
 396     return (false);
 397   }
 398   if (mCallsign.empty())
 399     mCallsign = "JohnDoe"; // FIXME: use getpwuid
 400   SG_LOG(SG_NETWORK,SG_INFO,"FGMultiplayMgr::init-txaddress= "<<txAddress);
 401   SG_LOG(SG_NETWORK,SG_INFO,"FGMultiplayMgr::init-txport= "<<txPort );
 402   SG_LOG(SG_NETWORK,SG_INFO,"FGMultiplayMgr::init-rxaddress="<<rxAddress );
 403   SG_LOG(SG_NETWORK,SG_INFO,"FGMultiplayMgr::init-rxport= "<<rxPort);
 404   SG_LOG(SG_NETWORK,SG_INFO,"FGMultiplayMgr::init-callsign= "<<mCallsign);
 405   Close(); // Should Init be called twice, close Socket first
 406            // A memory leak was reported here by valgrind
 407   mSocket = new netSocket();
 408   if (!mSocket->open(false)) {
 409     SG_LOG( SG_NETWORK, SG_ALERT,
 410             "FGMultiplayMgr::init - Failed to create data socket" );
 411     return false;
 412   }
 413   mSocket->setBlocking(false);
 414   if (mSocket->bind(rxAddress.c_str(), rxPort) != 0) {
 415     perror("bind");
 416     SG_LOG( SG_NETWORK, SG_ALERT,
 417             "FGMultiplayMgr::Open - Failed to bind receive socket" );
 418     return false;
 419   }
 420   mInitialised = true;
 421   return true;
 422 } // FGMultiplayMgr::init()
 423 //////////////////////////////////////////////////////////////////////
 424
 425 //////////////////////////////////////////////////////////////////////
 426 //
 427 //  Closes and deletes the local player object. Closes
 428 //  and deletes the tx socket. Resets the object state to unitialised.
 429 //
 430 //////////////////////////////////////////////////////////////////////
 431 void
 432 FGMultiplayMgr::Close (void)
 433 {
 434   mMultiPlayerMap.clear();
 435
 436   if (mSocket) {
 437     mSocket->close();
 438     delete mSocket;
 439     mSocket = 0;
 440   }
 441   mInitialised = false;
 442 } // FGMultiplayMgr::Close(void)
 443 //////////////////////////////////////////////////////////////////////
 444
 445 //////////////////////////////////////////////////////////////////////
 446 //
 447 //  Description: Sends the position data for the local position.
 448 //
 449 //////////////////////////////////////////////////////////////////////
 450 void
 451 FGMultiplayMgr::SendMyPosition(const FGExternalMotionData& motionInfo)
 452 {
 453   if ((! mInitialised) || (! mHaveServer))
 454         return;
 455   if (! mHaveServer) {
 456     SG_LOG( SG_NETWORK, SG_ALERT, "FGMultiplayMgr::SendMyPosition - no server");
 457     return;
 458   }
 459
 460   T_PositionMsg PosMsg;
 461
 462   memset(&PosMsg, 0, sizeof(PosMsg));
 463   strncpy(PosMsg.Model, fgGetString("/sim/model/path"), MAX_MODEL_NAME_LEN);
 464   PosMsg.Model[MAX_MODEL_NAME_LEN - 1] = '\0';
 465
 466   PosMsg.time = XDR_encode_double (motionInfo.time);
 467   PosMsg.lag = XDR_encode_double (motionInfo.lag);
 468   for (unsigned i = 0 ; i < 3; ++i)
 469     PosMsg.position[i] = XDR_encode_double (motionInfo.position(i));
 470   SGVec3f angleAxis;
 471   motionInfo.orientation.getAngleAxis(angleAxis);
 472   for (unsigned i = 0 ; i < 3; ++i)
 473     PosMsg.orientation[i] = XDR_encode_float (angleAxis(i));
 474   for (unsigned i = 0 ; i < 3; ++i)
 475     PosMsg.linearVel[i] = XDR_encode_float (motionInfo.linearVel(i));
 476   for (unsigned i = 0 ; i < 3; ++i)
 477     PosMsg.angularVel[i] = XDR_encode_float (motionInfo.angularVel(i));
 478   for (unsigned i = 0 ; i < 3; ++i)
 479     PosMsg.linearAccel[i] = XDR_encode_float (motionInfo.linearAccel(i));
 480   for (unsigned i = 0 ; i < 3; ++i)
 481     PosMsg.angularAccel[i] = XDR_encode_float (motionInfo.angularAccel(i));
 482   // ensure alignment of message buffer
 483   union {
 484     xdr_data2_t double_val;
 485     char Msg[MAX_PACKET_SIZE];
 486   } msgBuf;
 487   memcpy(msgBuf.Msg + sizeof(T_MsgHdr), &PosMsg, sizeof(T_PositionMsg));
 488
 489   xdr_data_t* ptr = reinterpret_cast<xdr_data_t*>(msgBuf.Msg + sizeof(T_MsgHdr)
 490                                                   + sizeof(T_PositionMsg));
 491   std::vector<FGPropertyData*>::const_iterator it;
 492   it = motionInfo.properties.begin();
 493   //cout << "OUTPUT PROPERTIES\n";
 494   xdr_data_t* msgEnd = reinterpret_cast<xdr_data_t*>(msgBuf.Msg
 495                                                      + MAX_PACKET_SIZE);
 496   while (it != motionInfo.properties.end() && ptr + 2 < msgEnd) {
 497
 498     // First element is the ID. Write it out when we know we have room for
 499     // the whole property.
 500     xdr_data_t id =  XDR_encode_uint32((*it)->id);
 501     // The actual data representation depends on the type
 502     switch ((*it)->type) {
 503       case SGPropertyNode::INT:
 504       case SGPropertyNode::BOOL:
 505       case SGPropertyNode::LONG:
 506         *ptr++ = id;
 507         *ptr++ = XDR_encode_uint32((*it)->int_value);
 508         //cout << "Prop:" << (*it)->id << " " << (*it)->type << " "<< (*it)->int_value << "\n";
 509         break;
 510       case SGPropertyNode::FLOAT:
 511       case SGPropertyNode::DOUBLE:
 512         *ptr++ = id;
 513         *ptr++ = XDR_encode_float((*it)->float_value);
 514         //cout << "Prop:" << (*it)->id << " " << (*it)->type << " "<< (*it)->float_value << "\n";
 515         break;
 516       case SGPropertyNode::STRING:
 517       case SGPropertyNode::UNSPECIFIED:
 518         {
 519           // String is complicated. It consists of
 520           // The length of the string
 521           // The string itself
 522           // Padding to the nearest 4-bytes.
 523           const char* lcharptr = (*it)->string_value;
 524
 525           if (lcharptr != 0)
 526           {
 527             // Add the length
 528             ////cout << "String length: " << strlen(lcharptr) << "\n";
 529             uint32_t len = strlen(lcharptr);
 530             if (len > MAX_TEXT_SIZE)
 531               len = MAX_TEXT_SIZE;
 532             // XXX This should not be using 4 bytes per character!
 533             // If there's not enough room for this property, drop it
 534             // on the floor.
 535             if (ptr + 2 + ((len + 3) & ~3) > msgEnd)
 536                 goto escape;
 537             //cout << "String length unint32: " << len << "\n";
 538             *ptr++ = id;
 539             *ptr++ = XDR_encode_uint32(len);
 540             if (len != 0)
 541             {
 542               // Now the text itself
 543               // XXX This should not be using 4 bytes per character!
 544               int lcount = 0;
 545               while ((*lcharptr != '\0') && (lcount < MAX_TEXT_SIZE))
 546               {
 547                 *ptr++ = XDR_encode_int8(*lcharptr);
 548                 lcharptr++;
 549                 lcount++;
 550               }
 551
 552               //cout << "Prop:" << (*it)->id << " " << (*it)->type << " " << len << " " << (*it)->string_value;
 553
 554               // Now pad if required
 555               while ((lcount % 4) != 0)
 556               {
 557                 *ptr++ = XDR_encode_int8(0);
 558                 lcount++;
 559                 //cout << "0";
 560               }
 561
 562               //cout << "\n";
 563             }
 564           }
 565           else
 566           {
 567             // Nothing to encode
 568             *ptr++ = id;
 569             *ptr++ = XDR_encode_uint32(0);
 570             //cout << "Prop:" << (*it)->id << " " << (*it)->type << " 0\n";
 571           }
 572         }
 573         break;
 574
 575       default:
 576         //cout << " Unknown Type: " << (*it)->type << "\n";
 577         *ptr++ = id;
 578         *ptr++ = XDR_encode_float((*it)->float_value);;
 579         //cout << "Prop:" << (*it)->id << " " << (*it)->type << " "<< (*it)->float_value << "\n";
 580         break;
 581     }
 582
 583     ++it;
 584   }
 585 escape:
 586
 587   T_MsgHdr MsgHdr;
 588   unsigned msgLen = reinterpret_cast<char*>(ptr) - msgBuf.Msg;
 589   FillMsgHdr(&MsgHdr, POS_DATA_ID, msgLen);
 590   memcpy(msgBuf.Msg, &MsgHdr, sizeof(T_MsgHdr));
 591
 592   mSocket->sendto(msgBuf.Msg, msgLen, 0, &mServer);
 593   SG_LOG(SG_NETWORK, SG_DEBUG, "FGMultiplayMgr::SendMyPosition");
 594 } // FGMultiplayMgr::SendMyPosition()
 595 //////////////////////////////////////////////////////////////////////
 596
 597 //////////////////////////////////////////////////////////////////////
 598 //
 599 //  Name: SendTextMessage
 600 //  Description: Sends a message to the player. The message must
 601 //  contain a valid and correctly filled out header and optional
 602 //  message body.
 603 //
 604 //////////////////////////////////////////////////////////////////////
 605 void
 606 FGMultiplayMgr::SendTextMessage(const string &MsgText)
 607 {
 608   if (!mInitialised || !mHaveServer)
 609     return;
 610
 611   T_MsgHdr MsgHdr;
 612   FillMsgHdr(&MsgHdr, CHAT_MSG_ID);
 613   //////////////////////////////////////////////////
 614   // Divide the text string into blocks that fit
 615   // in the message and send the blocks.
 616   //////////////////////////////////////////////////
 617   unsigned iNextBlockPosition = 0;
 618   T_ChatMsg ChatMsg;
 619
 620   char Msg[sizeof(T_MsgHdr) + sizeof(T_ChatMsg)];
 621   while (iNextBlockPosition < MsgText.length()) {
 622     strncpy (ChatMsg.Text,
 623              MsgText.substr(iNextBlockPosition, MAX_CHAT_MSG_LEN - 1).c_str(),
 624              MAX_CHAT_MSG_LEN);
 625     ChatMsg.Text[MAX_CHAT_MSG_LEN - 1] = '\0';
 626     memcpy (Msg, &MsgHdr, sizeof(T_MsgHdr));
 627     memcpy (Msg + sizeof(T_MsgHdr), &ChatMsg, sizeof(T_ChatMsg));
 628     mSocket->sendto (Msg, sizeof(T_MsgHdr) + sizeof(T_ChatMsg), 0, &mServer);
 629     iNextBlockPosition += MAX_CHAT_MSG_LEN - 1;
 630
 631   }
 632
 633
 634 } // FGMultiplayMgr::SendTextMessage ()
 635 //////////////////////////////////////////////////////////////////////
 636
 637 //////////////////////////////////////////////////////////////////////
 638 //
 639 //  Name: ProcessData
 640 //  Description: Processes data waiting at the receive socket. The
 641 //  processing ends when there is no more data at the socket.
 642 //
 643 //////////////////////////////////////////////////////////////////////
 644 void
 645 FGMultiplayMgr::Update(void)
 646 {
 647   if (!mInitialised)
 648     return;
 649
 650   /// Just for expiry
 651   SGTimeStamp timestamper;
 652   timestamper.stamp();
 653   long stamp = timestamper.get_seconds();
 654
 655   //////////////////////////////////////////////////
 656   //  Read the receive socket and process any data
 657   //////////////////////////////////////////////////
 658   int bytes;
 659   do {
 660     // ensure alignment
 661     union {
 662       xdr_data2_t doubleVal;
 663       char Msg[MAX_PACKET_SIZE];
 664     } msgBuf;
 665     //////////////////////////////////////////////////
 666     //  Although the recv call asks for
 667     //  MAX_PACKET_SIZE of data, the number of bytes
 668     //  returned will only be that of the next
 669     //  packet waiting to be processed.
 670     //////////////////////////////////////////////////
 671     netAddress SenderAddress;
 672     bytes = mSocket->recvfrom(msgBuf.Msg, sizeof(msgBuf.Msg), 0,
 673                               &SenderAddress);
 674     //////////////////////////////////////////////////
 675     //  no Data received
 676     //////////////////////////////////////////////////
 677     if (bytes <= 0) {
 678       if (errno != EAGAIN && errno != 0) // MSVC output "NoError" otherwise
 679         perror("FGMultiplayMgr::MP_ProcessData");
 680       break;
 681     }
 682     if (bytes <= sizeof(T_MsgHdr)) {
 683       SG_LOG( SG_NETWORK, SG_ALERT, "FGMultiplayMgr::MP_ProcessData - "
 684               << "received message with insufficient data" );
 685       break;
 686     }
 687     //////////////////////////////////////////////////
 688     //  Read header
 689     //////////////////////////////////////////////////
 690     T_MsgHdr* MsgHdr = reinterpret_cast<T_MsgHdr *>(msgBuf.Msg);
 691     MsgHdr->Magic       = XDR_decode_uint32 (MsgHdr->Magic);
 692     MsgHdr->Version     = XDR_decode_uint32 (MsgHdr->Version);
 693     MsgHdr->MsgId       = XDR_decode_uint32 (MsgHdr->MsgId);
 694     MsgHdr->MsgLen      = XDR_decode_uint32 (MsgHdr->MsgLen);
 695     MsgHdr->ReplyPort   = XDR_decode_uint32 (MsgHdr->ReplyPort);
 696     MsgHdr->Callsign[MAX_CALLSIGN_LEN -1] = '\0';
 697     if (MsgHdr->Magic != MSG_MAGIC) {
 698       SG_LOG( SG_NETWORK, SG_ALERT, "FGMultiplayMgr::MP_ProcessData - "
 699               << "message has invalid magic number!" );
 700       break;
 701     }
 702     if (MsgHdr->Version != PROTO_VER) {
 703       SG_LOG( SG_NETWORK, SG_ALERT, "FGMultiplayMgr::MP_ProcessData - "
 704               << "message has invalid protocoll number!" );
 705       break;
 706     }
 707     if (MsgHdr->MsgLen != bytes) {
 708       SG_LOG(SG_NETWORK, SG_ALERT, "FGMultiplayMgr::MP_ProcessData - "
 709              << "message from " << MsgHdr->Callsign << " has invalid length!");
 710       break;
 711     }
 712     //////////////////////////////////////////////////
 713     //  Process messages
 714     //////////////////////////////////////////////////
 715     switch (MsgHdr->MsgId) {
 716     case CHAT_MSG_ID:
 717       ProcessChatMsg(msgBuf.Msg, SenderAddress);
 718       break;
 719     case POS_DATA_ID:
 720       ProcessPosMsg(msgBuf.Msg, SenderAddress, bytes, stamp);
 721       break;
 722     case UNUSABLE_POS_DATA_ID:
 723     case OLD_OLD_POS_DATA_ID:
 724     case OLD_PROP_MSG_ID:
 725     case OLD_POS_DATA_ID:
 726       break;
 727     default:
 728       SG_LOG( SG_NETWORK, SG_ALERT, "FGMultiplayMgr::MP_ProcessData - "
 729               << "Unknown message Id received: " << MsgHdr->MsgId );
 730       break;
 731     }
 732   } while (bytes > 0);
 733
 734   // check for expiry
 735   MultiPlayerMap::iterator it = mMultiPlayerMap.begin();
 736   while (it != mMultiPlayerMap.end()) {
 737     if (it->second->getLastTimestamp() + 10 < stamp) {
 738       std::string name = it->first;
 739       it->second->setDie(true);
 740       mMultiPlayerMap.erase(it);
 741       it = mMultiPlayerMap.upper_bound(name);
 742     } else
 743       ++it;
 744   }
 745 } // FGMultiplayMgr::ProcessData(void)
 746 //////////////////////////////////////////////////////////////////////
 747
 748 //////////////////////////////////////////////////////////////////////
 749 //
 750 //  handle a position message
 751 //
 752 //////////////////////////////////////////////////////////////////////
 753 void
 754 FGMultiplayMgr::ProcessPosMsg(const char *Msg, netAddress & SenderAddress,
 755                               unsigned len, long stamp)
 756 {
 757   const T_MsgHdr* MsgHdr = reinterpret_cast<const T_MsgHdr *>(Msg);
 758   if (MsgHdr->MsgLen < sizeof(T_MsgHdr) + sizeof(T_PositionMsg)) {
 759     SG_LOG( SG_NETWORK, SG_ALERT, "FGMultiplayMgr::MP_ProcessData - "
 760             << "Position message received with insufficient data" );
 761     return;
 762   }
 763   const T_PositionMsg* PosMsg
 764     = reinterpret_cast<const T_PositionMsg *>(Msg + sizeof(T_MsgHdr));
 765   FGExternalMotionData motionInfo;
 766   motionInfo.time = XDR_decode_double(PosMsg->time);
 767   motionInfo.lag = XDR_decode_double(PosMsg->lag);
 768   for (unsigned i = 0; i < 3; ++i)
 769     motionInfo.position(i) = XDR_decode_double(PosMsg->position[i]);
 770   SGVec3f angleAxis;
 771   for (unsigned i = 0; i < 3; ++i)
 772     angleAxis(i) = XDR_decode_float(PosMsg->orientation[i]);
 773   motionInfo.orientation = SGQuatf::fromAngleAxis(angleAxis);
 774   for (unsigned i = 0; i < 3; ++i)
 775     motionInfo.linearVel(i) = XDR_decode_float(PosMsg->linearVel[i]);
 776   for (unsigned i = 0; i < 3; ++i)
 777     motionInfo.angularVel(i) = XDR_decode_float(PosMsg->angularVel[i]);
 778   for (unsigned i = 0; i < 3; ++i)
 779     motionInfo.linearAccel(i) = XDR_decode_float(PosMsg->linearAccel[i]);
 780   for (unsigned i = 0; i < 3; ++i)
 781     motionInfo.angularAccel(i) = XDR_decode_float(PosMsg->angularAccel[i]);
 782
 783
 784   //cout << "INPUT MESSAGE\n";
 785   const xdr_data_t* xdr = (xdr_data_t*)(Msg + sizeof(T_MsgHdr) + sizeof(T_PositionMsg));
 786   // There was a bug in 1.9.0 and before: T_PositionMsg was 196 bytes
 787   // on 32 bit architectures and 200 bytes on 64 bit, and this
 788   // structure is put directly on the wire. By looking at the padding,
 789   // we can sort through the mess, mostly:
 790   // If padding is 0 (which is not a valid property type), then the
 791   // message was produced by a new client or an old 64 bit client that
 792   // happened to have 0 on the stack;
 793   // Else if the property list starting with the padding word is
 794   // well-formed, then the client is probably an old 32 bit client and
 795   // we'll go with that;
 796   // Else it is an old 64-bit client and properties start after the
 797   // padding.
 798   // There is a chance that we could be fooled by garbage in the
 799   // padding looking like a valid property, so verifyProperties() is
 800   // strict about the validity of the property values.
 801   if (PosMsg->pad != 0) {
 802     if (verifyProperties(&PosMsg->pad,
 803                          reinterpret_cast<const xdr_data_t*>(Msg + len)))
 804       xdr = &PosMsg->pad;
 805     else if (!verifyProperties(xdr,
 806                                reinterpret_cast<const xdr_data_t*>(Msg + len)))
 807       goto noprops;
 808   }
 809   while ((char*)xdr < Msg + len) {
 810     FGPropertyData* pData = new FGPropertyData;
 811     SGPropertyNode::Type type = SGPropertyNode::UNSPECIFIED;
 812
 813     // First element is always the ID
 814     pData->id = XDR_decode_uint32(*xdr);
 815     //cout << pData->id << " ";
 816     xdr++;
 817
 818     // Check the ID actually exists and get the type
 819     const IdPropertyList* plist = findProperty(pData->id);
 820
 821     if (plist)
 822     {
 823       pData->type = plist->type;
 824       // How we decode the remainder of the property depends on the type
 825       switch (pData->type) {
 826         case SGPropertyNode::INT:
 827         case SGPropertyNode::BOOL:
 828         case SGPropertyNode::LONG:
 829           pData->int_value = XDR_decode_uint32(*xdr);
 830           xdr++;
 831           //cout << pData->int_value << "\n";
 832           break;
 833         case SGPropertyNode::FLOAT:
 834         case SGPropertyNode::DOUBLE:
 835           pData->float_value = XDR_decode_float(*xdr);
 836           xdr++;
 837           //cout << pData->float_value << "\n";
 838           break;
 839         case SGPropertyNode::STRING:
 840         case SGPropertyNode::UNSPECIFIED:
 841           {
 842             // String is complicated. It consists of
 843             // The length of the string
 844             // The string itself
 845             // Padding to the nearest 4-bytes.
 846             uint32_t length = XDR_decode_uint32(*xdr);
 847             xdr++;
 848             //cout << length << " ";
 849             // Old versions truncated the string but left the length unadjusted.
 850             if (length > MAX_TEXT_SIZE)
 851               length = MAX_TEXT_SIZE;
 852             pData->string_value = new char[length + 1];
 853             //cout << " String: ";
 854             for (int i = 0; i < length; i++)
 855               {
 856                 pData->string_value[i] = (char) XDR_decode_int8(*xdr);
 857                 xdr++;
 858                 //cout << pData->string_value[i];
 859               }
 860
 861             pData->string_value[length] = '\0';
 862
 863             // Now handle the padding
 864             while ((length % 4) != 0)
 865               {
 866                 xdr++;
 867                 length++;
 868                 //cout << "0";
 869               }
 870             //cout << "\n";
 871           }
 872           break;
 873
 874         default:
 875           pData->float_value = XDR_decode_float(*xdr);
 876           cerr << "Unknown Prop type " << pData->id << " " << pData->type << "\n";
 877           xdr++;
 878           break;
 879       }
 880
 881       motionInfo.properties.push_back(pData);
 882     }
 883     else
 884     {
 885       // We failed to find the property. We'll try the next packet immediately.
 886       SG_LOG(SG_NETWORK, SG_INFO, "FGMultiplayMgr::ProcessPosMsg - "
 887              "message from " << MsgHdr->Callsign << " has unknown property id "
 888              << pData->id);
 889     }
 890   }
 891  noprops:
 892   FGAIMultiplayer* mp = getMultiplayer(MsgHdr->Callsign);
 893   if (!mp)
 894     mp = addMultiplayer(MsgHdr->Callsign, PosMsg->Model);
 895   mp->addMotionInfo(motionInfo, stamp);
 896 } // FGMultiplayMgr::ProcessPosMsg()
 897 //////////////////////////////////////////////////////////////////////
 898
 899 //////////////////////////////////////////////////////////////////////
 900 //
 901 //  handle a chat message
 902 //  FIXME: display chat message withi flightgear
 903 //
 904 //////////////////////////////////////////////////////////////////////
 905 void
 906 FGMultiplayMgr::ProcessChatMsg(const char *Msg, netAddress& SenderAddress)
 907 {
 908   T_MsgHdr* MsgHdr = (T_MsgHdr *)Msg;
 909   if (MsgHdr->MsgLen < sizeof(T_MsgHdr) + 1) {
 910     SG_LOG( SG_NETWORK, SG_ALERT, "FGMultiplayMgr::MP_ProcessData - "
 911             << "Chat message received with insufficient data" );
 912     return;
 913   }
 914
 915   char *MsgBuf = new char[MsgHdr->MsgLen - sizeof(T_MsgHdr)];
 916   strncpy(MsgBuf, ((T_ChatMsg *)(Msg + sizeof(T_MsgHdr)))->Text,
 917           MsgHdr->MsgLen - sizeof(T_MsgHdr));
 918   MsgBuf[MsgHdr->MsgLen - sizeof(T_MsgHdr) - 1] = '\0';
 919
 920   T_ChatMsg* ChatMsg = (T_ChatMsg *)(Msg + sizeof(T_MsgHdr));
 921   SG_LOG (SG_NETWORK, SG_ALERT, "Chat [" << MsgHdr->Callsign << "]"
 922            << " " << MsgBuf);
 923
 924   delete [] MsgBuf;
 925 } // FGMultiplayMgr::ProcessChatMsg ()
 926 //////////////////////////////////////////////////////////////////////
 927
 928 void
 929 FGMultiplayMgr::FillMsgHdr(T_MsgHdr *MsgHdr, int MsgId, unsigned _len)
 930 {
 931   uint32_t len;
 932   switch (MsgId) {
 933   case CHAT_MSG_ID:
 934     len = sizeof(T_MsgHdr) + sizeof(T_ChatMsg);
 935     break;
 936   case POS_DATA_ID:
 937     len = _len;
 938     break;
 939   default:
 940     len = sizeof(T_MsgHdr);
 941     break;
 942   }
 943   MsgHdr->Magic           = XDR_encode_uint32(MSG_MAGIC);
 944   MsgHdr->Version         = XDR_encode_uint32(PROTO_VER);
 945   MsgHdr->MsgId           = XDR_encode_uint32(MsgId);
 946   MsgHdr->MsgLen          = XDR_encode_uint32(len);
 947   MsgHdr->ReplyAddress    = 0; // Are obsolete, keep them for the server for
 948   MsgHdr->ReplyPort       = 0; // now
 949   strncpy(MsgHdr->Callsign, mCallsign.c_str(), MAX_CALLSIGN_LEN);
 950   MsgHdr->Callsign[MAX_CALLSIGN_LEN - 1] = '\0';
 951 }
 952
 953 FGAIMultiplayer*
 954 FGMultiplayMgr::addMultiplayer(const std::string& callsign,
 955                                const std::string& modelName)
 956 {
 957   if (0 < mMultiPlayerMap.count(callsign))
 958     return mMultiPlayerMap[callsign].get();
 959
 960   FGAIMultiplayer* mp = new FGAIMultiplayer;
 961   mp->setPath(modelName.c_str());
 962   mp->setCallSign(callsign);
 963   mMultiPlayerMap[callsign] = mp;
 964
 965   FGAIManager *aiMgr = (FGAIManager*)globals->get_subsystem("ai_model");
 966   if (aiMgr) {
 967     aiMgr->attach(mp);
 968
 969     /// FIXME: that must follow the attach ATM ...
 970     for (unsigned i = 0; i < numProperties; ++i)
 971       mp->addPropertyId(sIdPropertyList[i].id, sIdPropertyList[i].name);
 972   }
 973
 974   return mp;
 975 }
 976
 977 FGAIMultiplayer*
 978 FGMultiplayMgr::getMultiplayer(const std::string& callsign)
 979 {
 980   if (0 < mMultiPlayerMap.count(callsign))
 981     return mMultiPlayerMap[callsign].get();
 982   else
 983     return 0;
 984 }