src/network.c

   1 // ============================================================================
   2 // Rocks'n'Diamonds - McDuffin Strikes Back!
   3 // ----------------------------------------------------------------------------
   4 // (c) 1995-2014 by Artsoft Entertainment
   5 //                  Holger Schemel
   6 //                  info@artsoft.org
   7 //                  http://www.artsoft.org/
   8 // ----------------------------------------------------------------------------
   9 // network.c
  10 // ============================================================================
  11
  12 #include <signal.h>
  13 #include <sys/time.h>
  14
  15 #include "libgame/libgame.h"
  16
  17 #include "network.h"
  18 #include "netserv.h"
  19 #include "main.h"
  20 #include "game.h"
  21 #include "tape.h"
  22 #include "files.h"
  23 #include "tools.h"
  24 #include "screens.h"
  25
  26 struct NetworkClientPlayerInfo
  27 {
  28   byte nr;
  29   char name[MAX_PLAYER_NAME_LEN + 1];
  30   struct NetworkClientPlayerInfo *next;
  31 };
  32
  33 static struct NetworkClientPlayerInfo first_player =
  34 {
  35   0,
  36   EMPTY_PLAYER_NAME,
  37   NULL
  38 };
  39
  40 /* server stuff */
  41
  42 static TCPsocket sfd;           /* TCP server socket */
  43 static UDPsocket udp;           /* UDP server socket */
  44 static SDLNet_SocketSet rfds;   /* socket set */
  45
  46 static byte realbuffer[512];
  47 static byte readbuffer[MAX_BUFFER_SIZE], writbuffer[MAX_BUFFER_SIZE];
  48 static byte *buffer = realbuffer + 4;
  49 static int nread = 0, nwrite = 0;
  50 static boolean stop_network_game = FALSE;
  51
  52 static void DrawNetworkTextExt(char *message, int font_nr, boolean initialize)
  53 {
  54   static int xpos = 0, ypos = 0;
  55   static int max_line_width = 0;
  56   int font_width = getFontWidth(font_nr);
  57   int font_height = getFontHeight(font_nr);
  58   int ypos_1 = 120;
  59   int ypos_2 = 150;
  60
  61   if (initialize)
  62   {
  63     if (game_status == GAME_MODE_LOADING)
  64     {
  65       max_line_width = WIN_XSIZE;
  66
  67       xpos = (max_line_width - getTextWidth(message, font_nr)) / 2;
  68       ypos = ypos_1;
  69
  70       DrawText(xpos, ypos, message, font_nr);
  71
  72       xpos = 0;
  73       ypos = ypos_2;
  74     }
  75     else
  76     {
  77       max_line_width = SXSIZE;
  78
  79       DrawTextSCentered(ypos_1, font_nr, message);
  80
  81       /* calculate offset to x position caused by rounding */
  82       int max_chars_per_line = max_line_width / font_width;
  83       int xoffset = (max_line_width - max_chars_per_line * font_width) / 2;
  84
  85       xpos = SX + xoffset;
  86       ypos = SY + ypos_2;
  87     }
  88
  89     Error(ERR_DEBUG, "========== %s ==========", message);
  90   }
  91   else
  92   {
  93     int max_chars_per_line = max_line_width / font_width;
  94     int max_lines_per_text = 10;
  95     int num_lines_spacing = (font_nr == FC_YELLOW ? 1 : 3);
  96     int num_lines_printed = DrawTextBuffer(xpos, ypos, message, font_nr,
  97                                            max_chars_per_line, -1,
  98                                            max_lines_per_text, 0, -1,
  99                                            TRUE, TRUE, FALSE);
 100
 101     ypos += (num_lines_printed + num_lines_spacing) * font_height;
 102
 103     Error(ERR_DEBUG, "%s", message);
 104   }
 105
 106   BackToFront();
 107 }
 108
 109 static void DrawNetworkText(char *message)
 110 {
 111   DrawNetworkTextExt(message, FC_YELLOW, FALSE);
 112 }
 113
 114 static void DrawNetworkText_Success(char *message)
 115 {
 116   DrawNetworkTextExt(message, FC_GREEN, FALSE);
 117 }
 118
 119 static void DrawNetworkText_Failed(char *message)
 120 {
 121   DrawNetworkTextExt(message, FC_RED, FALSE);
 122 }
 123
 124 static void DrawNetworkText_Title(char *message)
 125 {
 126   DrawNetworkTextExt(message, FC_GREEN, TRUE);
 127 }
 128
 129 static void SendBufferToServer(int size)
 130 {
 131   if (!network.enabled)
 132     return;
 133
 134   realbuffer[0] = realbuffer[1] = realbuffer[2] = 0;
 135   realbuffer[3] = (byte)size;
 136   buffer[0] = 0;
 137
 138   if (nwrite + 4 + size >= MAX_BUFFER_SIZE)
 139     Error(ERR_EXIT, "internal error: network send buffer overflow");
 140
 141   memcpy(writbuffer + nwrite, realbuffer, 4 + size);
 142   nwrite += 4 + size;
 143
 144   /* directly send the buffer to the network server */
 145   SDLNet_TCP_Send(sfd, writbuffer, nwrite);
 146   nwrite = 0;
 147 }
 148
 149 struct NetworkClientPlayerInfo *getNetworkPlayer(int player_nr)
 150 {
 151   struct NetworkClientPlayerInfo *player = NULL;
 152
 153   for (player = &first_player; player; player = player->next)
 154     if (player->nr == player_nr)
 155       break;
 156
 157   if (player == NULL)   /* should not happen */
 158     Error(ERR_EXIT, "protocol error: reference to non-existing player %d",
 159           player_nr);
 160
 161   return player;
 162 }
 163
 164 char *getNetworkPlayerName(int player_nr)
 165 {
 166   struct NetworkClientPlayerInfo *player;
 167
 168   if (player_nr == 0)
 169     return("the network game server");
 170   else if (player_nr == first_player.nr)
 171     return("you");
 172   else
 173     for (player = &first_player; player; player = player->next)
 174       if (player->nr == player_nr && strlen(player->name) > 0)
 175         return(player->name);
 176
 177   return(EMPTY_PLAYER_NAME);
 178 }
 179
 180 static void StartNetworkServer(int port)
 181 {
 182   static int p;
 183
 184   p = port;
 185 #if defined(TARGET_SDL2)
 186   server_thread = SDL_CreateThread(NetworkServerThread,
 187                                    "NetworkServerThread", &p);
 188 #else
 189   server_thread = SDL_CreateThread(NetworkServerThread, &p);
 190 #endif
 191   network_server = TRUE;
 192 }
 193
 194 boolean ConnectToServer(char *hostname, int port)
 195 {
 196   IPaddress ip;
 197   int server_host = 0;
 198   int i;
 199
 200   DrawNetworkText_Title("Initializing Network");
 201
 202   if (port == 0)
 203     port = DEFAULT_SERVER_PORT;
 204
 205   if (hostname == NULL)
 206   {
 207     // if no hostname given, try to auto-detect network server in local network
 208     // by doing a UDP broadcast on the network server port and wait for answer
 209
 210     SDLNet_SocketSet udp_socket_set = SDLNet_AllocSocketSet(1);
 211     if (!udp_socket_set)
 212       Error(ERR_EXIT, "SDLNet_AllocSocketSet() failed: %s"), SDLNet_GetError();
 213
 214     udp = SDLNet_UDP_Open(0);
 215     if(!udp)
 216       Error(ERR_EXIT, "SDLNet_UDP_Open() failed: %s", SDLNet_GetError());
 217
 218     if (SDLNet_UDP_AddSocket(udp_socket_set, udp) == -1)
 219       Error(ERR_EXIT_NETWORK_SERVER, "SDLNet_TCP_AddSocket() failed: %s"),
 220         SDLNet_GetError();
 221
 222     char *data_ptr = "network server UDB broadcast";
 223     int data_len = strlen(data_ptr) + 1;
 224     IPaddress ip_address;
 225
 226     SDLNet_Write32(0xffffffff, &ip_address.host);       /* 255.255.255.255 */
 227     SDLNet_Write16(port,       &ip_address.port);
 228
 229     UDPpacket packet =
 230     {
 231       -1,
 232       (Uint8 *)data_ptr,
 233       data_len,
 234       data_len,
 235       0,
 236       ip_address
 237     };
 238
 239     SDLNet_UDP_Send(udp, -1, &packet);
 240
 241     DrawNetworkText("Looking for local network server ...");
 242
 243     if (SDLNet_CheckSockets(udp_socket_set, 500) == 1)
 244     {
 245       int num_packets = SDLNet_UDP_Recv(udp, &packet);
 246
 247       if (num_packets == 1)
 248       {
 249         DrawNetworkText_Success("Network server found!");
 250
 251         server_host = SDLNet_Read32(&packet.address.host);
 252       }
 253       else
 254       {
 255         DrawNetworkText_Failed("No answer from network server!");
 256       }
 257     }
 258     else
 259     {
 260       DrawNetworkText_Failed("No network server found!");
 261     }
 262   }
 263
 264   rfds = SDLNet_AllocSocketSet(1);
 265
 266   if (hostname)
 267   {
 268     SDLNet_ResolveHost(&ip, hostname, port);
 269
 270     if (ip.host == INADDR_NONE)
 271       Error(ERR_EXIT, "cannot locate host '%s'", hostname);
 272     else
 273       server_host = SDLNet_Read32(&ip.host);
 274
 275     DrawNetworkText("Connecting to remote host ...");
 276   }
 277   else
 278   {
 279     // if no hostname was given and no network server was auto-detected in the
 280     // local network, try to connect to a network server at the local host
 281     if (server_host == 0)
 282       server_host = 0x7f000001;                 /* 127.0.0.1 */
 283
 284     SDLNet_Write32(server_host, &ip.host);
 285     SDLNet_Write16(port,        &ip.port);
 286
 287     DrawNetworkText("Connecting to local host ...");
 288   }
 289
 290   Error(ERR_DEBUG, "trying to connect to network server at %d.%d.%d.%d ...",
 291         (server_host >> 24) & 0xff,
 292         (server_host >> 16) & 0xff,
 293         (server_host >>  8) & 0xff,
 294         (server_host >>  0) & 0xff);
 295
 296   sfd = SDLNet_TCP_Open(&ip);
 297
 298   if (sfd)
 299   {
 300     SDLNet_TCP_AddSocket(rfds, sfd);
 301
 302     DrawNetworkText_Success("Successfully connected!");
 303
 304     return TRUE;
 305   }
 306   else
 307   {
 308     DrawNetworkText_Failed("Failed to connect to network server!");
 309
 310     printf("SDLNet_TCP_Open(): %s\n", SDLNet_GetError());
 311   }
 312
 313   if (hostname)                 /* connect to specified server failed */
 314     return FALSE;
 315
 316   DrawNetworkText("Starting new local network server ...");
 317
 318   StartNetworkServer(port);
 319
 320   /* wait for server to start up and try connecting several times */
 321   for (i = 0; i < 30; i++)
 322   {
 323     if ((sfd = SDLNet_TCP_Open(&ip)))           /* connected */
 324     {
 325       DrawNetworkText_Success("Successfully connected!");
 326
 327       SDLNet_TCP_AddSocket(rfds, sfd);
 328       return TRUE;
 329     }
 330
 331     Delay(100);
 332   }
 333
 334   DrawNetworkText_Failed("Failed to connect to network server!");
 335
 336   /* when reaching this point, connect to newly started server has failed */
 337   return FALSE;
 338 }
 339
 340 void SendToServer_PlayerName(char *player_name)
 341 {
 342   int len_player_name = strlen(player_name);
 343
 344   buffer[1] = OP_PLAYER_NAME;
 345   memcpy(&buffer[2], player_name, len_player_name);
 346   SendBufferToServer(2 + len_player_name);
 347   Error(ERR_NETWORK_CLIENT, "you set your player name to \"%s\"", player_name);
 348 }
 349
 350 void SendToServer_ProtocolVersion()
 351 {
 352   buffer[1] = OP_PROTOCOL_VERSION;
 353   buffer[2] = PROTOCOL_VERSION_1;
 354   buffer[3] = PROTOCOL_VERSION_2;
 355   buffer[4] = PROTOCOL_VERSION_3;
 356
 357   SendBufferToServer(5);
 358 }
 359
 360 void SendToServer_NrWanted(int nr_wanted)
 361 {
 362   buffer[1] = OP_NUMBER_WANTED;
 363   buffer[2] = nr_wanted;
 364
 365   SendBufferToServer(3);
 366 }
 367
 368 void SendToServer_StartPlaying()
 369 {
 370   unsigned int new_random_seed = InitRND(level.random_seed);
 371
 372   int dummy = 0;                /* !!! HAS NO MEANING ANYMORE !!! */
 373                                 /* the name of the level must be enough */
 374
 375   buffer[1] = OP_START_PLAYING;
 376   buffer[2] = (byte)(level_nr >> 8);
 377   buffer[3] = (byte)(level_nr & 0xff);
 378   buffer[4] = (byte)(dummy >> 8);
 379   buffer[5] = (byte)(dummy & 0xff);
 380
 381   buffer[6] = (unsigned char)((new_random_seed >> 24) & 0xff);
 382   buffer[7] = (unsigned char)((new_random_seed >> 16) & 0xff);
 383   buffer[8] = (unsigned char)((new_random_seed >>  8) & 0xff);
 384   buffer[9] = (unsigned char)((new_random_seed >>  0) & 0xff);
 385
 386   strcpy((char *)&buffer[10], leveldir_current->identifier);
 387
 388   SendBufferToServer(10 + strlen(leveldir_current->identifier) + 1);
 389 }
 390
 391 void SendToServer_PausePlaying()
 392 {
 393   buffer[1] = OP_PAUSE_PLAYING;
 394
 395   SendBufferToServer(2);
 396 }
 397
 398 void SendToServer_ContinuePlaying()
 399 {
 400   buffer[1] = OP_CONTINUE_PLAYING;
 401
 402   SendBufferToServer(2);
 403 }
 404
 405 void SendToServer_StopPlaying(int cause_for_stopping)
 406 {
 407   buffer[1] = OP_STOP_PLAYING;
 408   buffer[2] = cause_for_stopping;
 409
 410   SendBufferToServer(3);
 411 }
 412
 413 void SendToServer_MovePlayer(byte player_action)
 414 {
 415   buffer[1] = OP_MOVE_PLAYER;
 416   buffer[2] = player_action;
 417
 418   SendBufferToServer(3);
 419 }
 420
 421 static void Handle_OP_BAD_PROTOCOL_VERSION()
 422 {
 423   Error(ERR_WARN, "protocol version mismatch");
 424   Error(ERR_EXIT, "server expects %d.%d.x instead of %d.%d.%d",
 425         buffer[2], buffer[3],
 426         PROTOCOL_VERSION_1, PROTOCOL_VERSION_2, PROTOCOL_VERSION_3);
 427 }
 428
 429 static void Handle_OP_YOUR_NUMBER()
 430 {
 431   int new_client_nr = buffer[2];
 432   int new_index_nr = new_client_nr - 1;
 433   struct PlayerInfo *old_local_player = local_player;
 434   struct PlayerInfo *new_local_player = &stored_player[new_index_nr];
 435
 436   printf("OP_YOUR_NUMBER: %d\n", buffer[0]);
 437   first_player.nr = new_client_nr;
 438
 439   if (old_local_player != new_local_player)
 440   {
 441     /* set relevant player settings and change to new player */
 442
 443     local_player = new_local_player;
 444
 445     old_local_player->connected_locally = FALSE;
 446     new_local_player->connected_locally = TRUE;
 447
 448     old_local_player->connected_network = FALSE;
 449     new_local_player->connected_network = TRUE;
 450   }
 451
 452   if (first_player.nr > MAX_PLAYERS)
 453     Error(ERR_EXIT, "sorry, more than %d players not allowed", MAX_PLAYERS);
 454
 455   Error(ERR_NETWORK_CLIENT, "you get client # %d", new_client_nr);
 456 }
 457
 458 static void Handle_OP_NUMBER_WANTED()
 459 {
 460   int client_nr_wanted = buffer[2];
 461   int old_client_nr = buffer[0];
 462   int new_client_nr = buffer[3];
 463   int old_index_nr = old_client_nr - 1;
 464   int new_index_nr = new_client_nr - 1;
 465   int index_nr_wanted = client_nr_wanted - 1;
 466   struct PlayerInfo *old_player = &stored_player[old_index_nr];
 467   struct PlayerInfo *new_player = &stored_player[new_index_nr];
 468
 469   printf("OP_NUMBER_WANTED: %d\n", buffer[0]);
 470
 471   if (new_client_nr == client_nr_wanted)        /* switching succeeded */
 472   {
 473     struct NetworkClientPlayerInfo *player;
 474
 475     if (old_client_nr != client_nr_wanted)      /* client's nr has changed */
 476       Error(ERR_NETWORK_CLIENT, "client %d switches to # %d",
 477             old_client_nr, new_client_nr);
 478     else if (old_client_nr == first_player.nr)  /* local player keeps his nr */
 479       Error(ERR_NETWORK_CLIENT, "keeping client # %d", new_client_nr);
 480
 481     if (old_client_nr != new_client_nr)
 482     {
 483       /* set relevant player settings and change to new player */
 484
 485       old_player->connected_network = FALSE;
 486       new_player->connected_network = TRUE;
 487     }
 488
 489     player = getNetworkPlayer(old_client_nr);
 490     player->nr = new_client_nr;
 491
 492     if (old_player == local_player)             /* local player switched */
 493     {
 494       local_player = new_player;
 495
 496       old_player->connected_locally = FALSE;
 497       new_player->connected_locally = TRUE;
 498     }
 499   }
 500   else if (old_client_nr == first_player.nr)    /* failed -- local player? */
 501   {
 502     char request[100];
 503
 504     sprintf(request, "Sorry! Player %d already exists! You are player %d!",
 505             index_nr_wanted + 1, new_index_nr + 1);
 506
 507     Request(request, REQ_CONFIRM);
 508
 509     Error(ERR_NETWORK_CLIENT, "cannot switch -- you keep client # %d",
 510           new_client_nr);
 511   }
 512 }
 513
 514 static void Handle_OP_PLAYER_NAME(unsigned int len)
 515 {
 516   struct NetworkClientPlayerInfo *player;
 517   int player_nr = (int)buffer[0];
 518
 519   printf("OP_PLAYER_NAME: %d\n", player_nr);
 520   player = getNetworkPlayer(player_nr);
 521   buffer[len] = 0;
 522   Error(ERR_NETWORK_CLIENT, "client %d calls itself \"%s\"",
 523         buffer[0], &buffer[2]);
 524   strncpy(player->name, (char *)&buffer[2], MAX_PLAYER_NAME_LEN);
 525 }
 526
 527 static void Handle_OP_PLAYER_CONNECTED()
 528 {
 529   struct NetworkClientPlayerInfo *player, *last_player = NULL;
 530   int new_client_nr = (int)buffer[0];
 531   int new_index_nr = new_client_nr - 1;
 532
 533   printf("OP_PLAYER_CONNECTED: %d\n", new_client_nr);
 534   Error(ERR_NETWORK_CLIENT, "new client %d connected", new_client_nr);
 535
 536   for (player = &first_player; player; player = player->next)
 537   {
 538     if (player->nr == new_client_nr)
 539       Error(ERR_EXIT, "multiplayer server sent duplicate player id");
 540
 541     last_player = player;
 542   }
 543
 544   last_player->next = player =
 545     checked_malloc(sizeof(struct NetworkClientPlayerInfo));
 546   player->nr = new_client_nr;
 547   player->name[0] = '\0';
 548   player->next = NULL;
 549
 550   stored_player[new_index_nr].connected_network = TRUE;
 551 }
 552
 553 static void Handle_OP_PLAYER_DISCONNECTED()
 554 {
 555   struct NetworkClientPlayerInfo *player, *player_disconnected;
 556   int player_nr = (int)buffer[0];
 557   int index_nr = player_nr - 1;
 558
 559   printf("OP_PLAYER_DISCONNECTED: %d\n", player_nr);
 560   player_disconnected = getNetworkPlayer(player_nr);
 561   Error(ERR_NETWORK_CLIENT, "client %d (%s) disconnected",
 562         player_nr, getNetworkPlayerName(buffer[0]));
 563
 564   for (player = &first_player; player; player = player->next)
 565     if (player->next == player_disconnected)
 566       player->next = player_disconnected->next;
 567   free(player_disconnected);
 568
 569   stored_player[index_nr].connected_locally = FALSE;
 570   stored_player[index_nr].connected_network = FALSE;
 571 }
 572
 573 static void Handle_OP_START_PLAYING()
 574 {
 575   LevelDirTree *new_leveldir;
 576   int new_level_nr;
 577   unsigned int new_random_seed;
 578   char *new_leveldir_identifier;
 579
 580   new_level_nr = (buffer[2] << 8) + buffer[3];
 581   new_random_seed =
 582     (buffer[6] << 24) | (buffer[7] << 16) | (buffer[8] << 8) | (buffer[9]);
 583   new_leveldir_identifier = (char *)&buffer[10];
 584
 585   new_leveldir = getTreeInfoFromIdentifier(leveldir_first,
 586                                            new_leveldir_identifier);
 587   if (new_leveldir == NULL)
 588   {
 589     Error(ERR_WARN, "no such level identifier: '%s'", new_leveldir_identifier);
 590
 591     new_leveldir = leveldir_first;
 592     Error(ERR_WARN, "using default level set: '%s'", new_leveldir->identifier);
 593   }
 594
 595   printf("OP_START_PLAYING: %d\n", buffer[0]);
 596   Error(ERR_NETWORK_CLIENT,
 597         "client %d starts game [level %d from level identifier '%s']\n",
 598         buffer[0], new_level_nr, new_leveldir->identifier);
 599
 600   leveldir_current = new_leveldir;
 601   level_nr = new_level_nr;
 602
 603   TapeErase();
 604   LoadTape(level_nr);
 605   LoadLevel(level_nr);
 606
 607   StartGameActions(FALSE, setup.autorecord, new_random_seed);
 608 }
 609
 610 static void Handle_OP_PAUSE_PLAYING()
 611 {
 612   printf("OP_PAUSE_PLAYING: %d\n", buffer[0]);
 613   Error(ERR_NETWORK_CLIENT, "client %d pauses game", buffer[0]);
 614
 615   tape.pausing = TRUE;
 616   DrawVideoDisplay(VIDEO_STATE_PAUSE_ON,0);
 617 }
 618
 619 static void Handle_OP_CONTINUE_PLAYING()
 620 {
 621   printf("OP_CONTINUE_PLAYING: %d\n", buffer[0]);
 622   Error(ERR_NETWORK_CLIENT, "client %d continues game", buffer[0]);
 623
 624   tape.pausing = FALSE;
 625   DrawVideoDisplay(VIDEO_STATE_PAUSE_OFF,0);
 626 }
 627
 628 static void Handle_OP_STOP_PLAYING()
 629 {
 630   printf("OP_STOP_PLAYING: %d [%d]\n", buffer[0], buffer[2]);
 631   Error(ERR_NETWORK_CLIENT, "client %d stops game [%d]", buffer[0], buffer[2]);
 632
 633   if (game_status == GAME_MODE_PLAYING)
 634   {
 635     int client_nr = buffer[0];
 636     int index_nr = client_nr - 1;
 637     struct PlayerInfo *client_player = &stored_player[index_nr];
 638     boolean stopped_by_remote_player = (!client_player->connected_locally);
 639     char *message = (buffer[2] == NETWORK_STOP_BY_PLAYER ?
 640                      "Network game stopped by player!" :
 641                      buffer[2] == NETWORK_STOP_BY_ERROR ?
 642                      "Network game stopped due to internal error!" :
 643                      "Network game stopped!");
 644
 645     if (buffer[2] != NETWORK_STOP_BY_PLAYER || stopped_by_remote_player)
 646       Request(message, REQ_CONFIRM | REQ_STAY_CLOSED);
 647   }
 648
 649   SetGameStatus(GAME_MODE_MAIN);
 650
 651   DrawMainMenu();
 652 }
 653
 654 static void Handle_OP_MOVE_PLAYER(unsigned int len)
 655 {
 656   int server_frame_counter;
 657   int i;
 658
 659   if (!network_playing)
 660     return;
 661
 662   server_frame_counter =
 663     (buffer[2] << 24) | (buffer[3] << 16) | (buffer[4] << 8) | (buffer[5]);
 664
 665   if (server_frame_counter != FrameCounter)
 666   {
 667     Error(ERR_INFO, "client and servers frame counters out of sync");
 668     Error(ERR_INFO, "frame counter of client is %d", FrameCounter);
 669     Error(ERR_INFO, "frame counter of server is %d", server_frame_counter);
 670     Error(ERR_INFO, "this should not happen -- please debug");
 671
 672     stop_network_game = TRUE;
 673
 674     return;
 675   }
 676
 677   /* copy valid player actions */
 678   for (i = 0; i < MAX_PLAYERS; i++)
 679     stored_player[i].effective_action =
 680       (i < len - 6 ? buffer[6 + i] : 0);
 681
 682   network_player_action_received = TRUE;
 683 }
 684
 685 static void HandleNetworkingMessages()
 686 {
 687   unsigned int message_length;
 688
 689   stop_network_game = FALSE;
 690
 691   while (nread >= 4 && nread >= 4 + readbuffer[3])
 692   {
 693     message_length = readbuffer[3];
 694     if (readbuffer[0] || readbuffer[1] || readbuffer[2])
 695       Error(ERR_EXIT, "wrong network server line length");
 696
 697     memcpy(buffer, &readbuffer[4], message_length);
 698     nread -= 4 + message_length;
 699     memmove(readbuffer, readbuffer + 4 + message_length, nread);
 700
 701     switch (buffer[1])
 702     {
 703       case OP_BAD_PROTOCOL_VERSION:
 704         Handle_OP_BAD_PROTOCOL_VERSION();
 705         break;
 706
 707       case OP_YOUR_NUMBER:
 708         Handle_OP_YOUR_NUMBER();
 709         break;
 710
 711       case OP_NUMBER_WANTED:
 712         Handle_OP_NUMBER_WANTED();
 713         break;
 714
 715       case OP_PLAYER_NAME:
 716         Handle_OP_PLAYER_NAME(message_length);
 717         break;
 718
 719       case OP_PLAYER_CONNECTED:
 720         Handle_OP_PLAYER_CONNECTED();
 721         break;
 722
 723       case OP_PLAYER_DISCONNECTED:
 724         Handle_OP_PLAYER_DISCONNECTED();
 725         break;
 726
 727       case OP_START_PLAYING:
 728         Handle_OP_START_PLAYING();
 729         break;
 730
 731       case OP_PAUSE_PLAYING:
 732         Handle_OP_PAUSE_PLAYING();
 733         break;
 734
 735       case OP_CONTINUE_PLAYING:
 736         Handle_OP_CONTINUE_PLAYING();
 737         break;
 738
 739       case OP_STOP_PLAYING:
 740         Handle_OP_STOP_PLAYING();
 741         break;
 742
 743       case OP_MOVE_PLAYER:
 744         Handle_OP_MOVE_PLAYER(message_length);
 745         break;
 746
 747       case OP_BROADCAST_MESSAGE:
 748         printf("OP_BROADCAST_MESSAGE: %d\n", buffer[0]);
 749         Error(ERR_NETWORK_CLIENT, "client %d sends message", buffer[0]);
 750         break;
 751     }
 752   }
 753
 754   fflush(stdout);
 755
 756   /* in case of internal error, stop network game */
 757   if (stop_network_game)
 758     SendToServer_StopPlaying(NETWORK_STOP_BY_ERROR);
 759 }
 760
 761 static char *HandleNetworkingPackets()
 762 {
 763   while (1)
 764   {
 765     /* ---------- check network server for activity ---------- */
 766
 767     int num_active_sockets = SDLNet_CheckSockets(rfds, 1);
 768
 769     if (num_active_sockets < 0)
 770       return "Error checking network sockets!";
 771
 772     if (num_active_sockets == 0)
 773       break;    // no active sockets, stop here
 774
 775     /* ---------- read packets from network server ---------- */
 776
 777     int num_bytes = SDLNet_TCP_Recv(sfd, readbuffer + nread, 1);
 778
 779     if (num_bytes < 0)
 780       return "Error reading from network server!";
 781
 782     if (num_bytes == 0)
 783       return "Connection to network server lost!";
 784
 785     nread += num_bytes;
 786
 787     HandleNetworkingMessages();
 788   }
 789
 790   return NULL;
 791 }
 792
 793 static void HandleNetworkingDisconnect()
 794 {
 795   int i;
 796
 797   SDLNet_TCP_DelSocket(rfds, sfd);
 798   SDLNet_TCP_Close(sfd);
 799
 800   network_playing = FALSE;
 801
 802   network.enabled = FALSE;
 803   network.connected = FALSE;
 804
 805   setup.network_mode = FALSE;
 806
 807   for (i = 0; i < MAX_PLAYERS; i++)
 808     stored_player[i].connected_network = FALSE;
 809 }
 810
 811 void HandleNetworking()
 812 {
 813   char *error_message = HandleNetworkingPackets();
 814
 815   if (error_message != NULL)
 816   {
 817     HandleNetworkingDisconnect();
 818
 819     if (game_status == GAME_MODE_PLAYING)
 820     {
 821       Request(error_message, REQ_CONFIRM | REQ_STAY_CLOSED);
 822
 823       SetGameStatus(GAME_MODE_MAIN);
 824
 825       DrawMainMenu();
 826     }
 827     else
 828     {
 829       Request(error_message, REQ_CONFIRM);
 830     }
 831   }
 832 }
 833
 834 void DisconnectFromNetworkServer()
 835 {
 836   DrawNetworkText_Title("Terminating Network");
 837   DrawNetworkText("Disconnecting from network server ...");
 838
 839   HandleNetworkingDisconnect();
 840
 841   DrawNetworkText_Success("Successfully disconnected!");
 842
 843   /* short time to recognize result of network initialization */
 844   Delay(1000);
 845 }