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     /* wait for any local network server to answer UDP broadcast */
 244     for (i = 0; i < 5; i++)
 245     {
 246       if (SDLNet_CheckSockets(udp_socket_set, 0) == 1)
 247       {
 248         int num_packets = SDLNet_UDP_Recv(udp, &packet);
 249
 250         if (num_packets == 1)
 251         {
 252           DrawNetworkText_Success("Network server found!");
 253
 254           server_host = SDLNet_Read32(&packet.address.host);
 255         }
 256         else
 257         {
 258           DrawNetworkText_Failed("No answer from network server!");
 259         }
 260
 261         break;
 262       }
 263       else
 264       {
 265         Delay_WithScreenUpdates(100);
 266       }
 267     }
 268
 269     if (server_host == 0)
 270       DrawNetworkText_Failed("No network server found!");
 271   }
 272
 273   rfds = SDLNet_AllocSocketSet(1);
 274
 275   if (hostname)
 276   {
 277     SDLNet_ResolveHost(&ip, hostname, port);
 278
 279     if (ip.host == INADDR_NONE)
 280       Error(ERR_EXIT, "cannot locate host '%s'", hostname);
 281     else
 282       server_host = SDLNet_Read32(&ip.host);
 283
 284     DrawNetworkText("Connecting to remote host ...");
 285   }
 286   else
 287   {
 288     // if no hostname was given and no network server was auto-detected in the
 289     // local network, try to connect to a network server at the local host
 290     if (server_host == 0)
 291       server_host = 0x7f000001;                 /* 127.0.0.1 */
 292
 293     SDLNet_Write32(server_host, &ip.host);
 294     SDLNet_Write16(port,        &ip.port);
 295
 296     DrawNetworkText("Connecting to local host ...");
 297   }
 298
 299   Error(ERR_DEBUG, "trying to connect to network server at %d.%d.%d.%d ...",
 300         (server_host >> 24) & 0xff,
 301         (server_host >> 16) & 0xff,
 302         (server_host >>  8) & 0xff,
 303         (server_host >>  0) & 0xff);
 304
 305   sfd = SDLNet_TCP_Open(&ip);
 306
 307   if (sfd)
 308   {
 309     SDLNet_TCP_AddSocket(rfds, sfd);
 310
 311     DrawNetworkText_Success("Successfully connected!");
 312
 313     return TRUE;
 314   }
 315   else
 316   {
 317     DrawNetworkText_Failed("Failed to connect to network server!");
 318
 319     printf("SDLNet_TCP_Open(): %s\n", SDLNet_GetError());
 320   }
 321
 322   if (hostname)                 /* connect to specified server failed */
 323     return FALSE;
 324
 325   DrawNetworkText("Starting new local network server ...");
 326
 327   StartNetworkServer(port);
 328
 329   /* wait for server to start up and try connecting several times */
 330   for (i = 0; i < 30; i++)
 331   {
 332     if ((sfd = SDLNet_TCP_Open(&ip)))           /* connected */
 333     {
 334       DrawNetworkText_Success("Successfully connected!");
 335
 336       SDLNet_TCP_AddSocket(rfds, sfd);
 337       return TRUE;
 338     }
 339
 340     Delay_WithScreenUpdates(100);
 341   }
 342
 343   DrawNetworkText_Failed("Failed to connect to network server!");
 344
 345   /* when reaching this point, connect to newly started server has failed */
 346   return FALSE;
 347 }
 348
 349 void SendToServer_PlayerName(char *player_name)
 350 {
 351   int len_player_name = strlen(player_name);
 352
 353   buffer[1] = OP_PLAYER_NAME;
 354   memcpy(&buffer[2], player_name, len_player_name);
 355   SendBufferToServer(2 + len_player_name);
 356   Error(ERR_NETWORK_CLIENT, "you set your player name to \"%s\"", player_name);
 357 }
 358
 359 void SendToServer_ProtocolVersion()
 360 {
 361   buffer[1] = OP_PROTOCOL_VERSION;
 362   buffer[2] = PROTOCOL_VERSION_1;
 363   buffer[3] = PROTOCOL_VERSION_2;
 364   buffer[4] = PROTOCOL_VERSION_3;
 365
 366   SendBufferToServer(5);
 367 }
 368
 369 void SendToServer_NrWanted(int nr_wanted)
 370 {
 371   buffer[1] = OP_NUMBER_WANTED;
 372   buffer[2] = nr_wanted;
 373
 374   SendBufferToServer(3);
 375 }
 376
 377 void SendToServer_StartPlaying()
 378 {
 379   unsigned int new_random_seed = InitRND(level.random_seed);
 380
 381   int dummy = 0;                /* !!! HAS NO MEANING ANYMORE !!! */
 382                                 /* the name of the level must be enough */
 383
 384   buffer[1] = OP_START_PLAYING;
 385   buffer[2] = (byte)(level_nr >> 8);
 386   buffer[3] = (byte)(level_nr & 0xff);
 387   buffer[4] = (byte)(dummy >> 8);
 388   buffer[5] = (byte)(dummy & 0xff);
 389
 390   buffer[6] = (unsigned char)((new_random_seed >> 24) & 0xff);
 391   buffer[7] = (unsigned char)((new_random_seed >> 16) & 0xff);
 392   buffer[8] = (unsigned char)((new_random_seed >>  8) & 0xff);
 393   buffer[9] = (unsigned char)((new_random_seed >>  0) & 0xff);
 394
 395   strcpy((char *)&buffer[10], leveldir_current->identifier);
 396
 397   SendBufferToServer(10 + strlen(leveldir_current->identifier) + 1);
 398 }
 399
 400 void SendToServer_PausePlaying()
 401 {
 402   buffer[1] = OP_PAUSE_PLAYING;
 403
 404   SendBufferToServer(2);
 405 }
 406
 407 void SendToServer_ContinuePlaying()
 408 {
 409   buffer[1] = OP_CONTINUE_PLAYING;
 410
 411   SendBufferToServer(2);
 412 }
 413
 414 void SendToServer_StopPlaying(int cause_for_stopping)
 415 {
 416   buffer[1] = OP_STOP_PLAYING;
 417   buffer[2] = cause_for_stopping;
 418
 419   SendBufferToServer(3);
 420 }
 421
 422 void SendToServer_MovePlayer(byte player_action)
 423 {
 424   buffer[1] = OP_MOVE_PLAYER;
 425   buffer[2] = player_action;
 426
 427   SendBufferToServer(3);
 428 }
 429
 430 static void Handle_OP_BAD_PROTOCOL_VERSION()
 431 {
 432   Error(ERR_WARN, "protocol version mismatch");
 433   Error(ERR_EXIT, "server expects %d.%d.x instead of %d.%d.%d",
 434         buffer[2], buffer[3],
 435         PROTOCOL_VERSION_1, PROTOCOL_VERSION_2, PROTOCOL_VERSION_3);
 436 }
 437
 438 static void Handle_OP_YOUR_NUMBER()
 439 {
 440   int new_client_nr = buffer[2];
 441   int new_index_nr = new_client_nr - 1;
 442   struct PlayerInfo *old_local_player = local_player;
 443   struct PlayerInfo *new_local_player = &stored_player[new_index_nr];
 444
 445   printf("OP_YOUR_NUMBER: %d\n", buffer[0]);
 446   first_player.nr = new_client_nr;
 447
 448   if (old_local_player != new_local_player)
 449   {
 450     /* set relevant player settings and change to new player */
 451
 452     local_player = new_local_player;
 453
 454     old_local_player->connected_locally = FALSE;
 455     new_local_player->connected_locally = TRUE;
 456
 457     old_local_player->connected_network = FALSE;
 458     new_local_player->connected_network = TRUE;
 459   }
 460
 461   if (first_player.nr > MAX_PLAYERS)
 462     Error(ERR_EXIT, "sorry, more than %d players not allowed", MAX_PLAYERS);
 463
 464   Error(ERR_NETWORK_CLIENT, "you get client # %d", new_client_nr);
 465
 466   stored_player[new_index_nr].connected_network = TRUE;
 467 }
 468
 469 static void Handle_OP_NUMBER_WANTED()
 470 {
 471   int client_nr_wanted = buffer[2];
 472   int old_client_nr = buffer[0];
 473   int new_client_nr = buffer[3];
 474   int old_index_nr = old_client_nr - 1;
 475   int new_index_nr = new_client_nr - 1;
 476   int index_nr_wanted = client_nr_wanted - 1;
 477   struct PlayerInfo *old_player = &stored_player[old_index_nr];
 478   struct PlayerInfo *new_player = &stored_player[new_index_nr];
 479
 480   printf("OP_NUMBER_WANTED: %d\n", buffer[0]);
 481
 482   if (new_client_nr == client_nr_wanted)        /* switching succeeded */
 483   {
 484     struct NetworkClientPlayerInfo *player;
 485
 486     if (old_client_nr != client_nr_wanted)      /* client's nr has changed */
 487       Error(ERR_NETWORK_CLIENT, "client %d switches to # %d",
 488             old_client_nr, new_client_nr);
 489     else if (old_client_nr == first_player.nr)  /* local player keeps his nr */
 490       Error(ERR_NETWORK_CLIENT, "keeping client # %d", new_client_nr);
 491
 492     if (old_client_nr != new_client_nr)
 493     {
 494       /* set relevant player settings and change to new player */
 495
 496       old_player->connected_network = FALSE;
 497       new_player->connected_network = TRUE;
 498     }
 499
 500     player = getNetworkPlayer(old_client_nr);
 501     player->nr = new_client_nr;
 502
 503     if (old_player == local_player)             /* local player switched */
 504     {
 505       local_player = new_player;
 506
 507       old_player->connected_locally = FALSE;
 508       new_player->connected_locally = TRUE;
 509     }
 510   }
 511   else if (old_client_nr == first_player.nr)    /* failed -- local player? */
 512   {
 513     char request[100];
 514
 515     sprintf(request, "Sorry! Player %d already exists! You are player %d!",
 516             index_nr_wanted + 1, new_index_nr + 1);
 517
 518     Request(request, REQ_CONFIRM);
 519
 520     Error(ERR_NETWORK_CLIENT, "cannot switch -- you keep client # %d",
 521           new_client_nr);
 522   }
 523
 524   if (game_status == GAME_MODE_MAIN)
 525     DrawNetworkPlayers();
 526 }
 527
 528 static void Handle_OP_PLAYER_NAME(unsigned int len)
 529 {
 530   struct NetworkClientPlayerInfo *player;
 531   int player_nr = (int)buffer[0];
 532
 533   printf("OP_PLAYER_NAME: %d\n", player_nr);
 534   player = getNetworkPlayer(player_nr);
 535   buffer[len] = 0;
 536   Error(ERR_NETWORK_CLIENT, "client %d calls itself \"%s\"",
 537         buffer[0], &buffer[2]);
 538   strncpy(player->name, (char *)&buffer[2], MAX_PLAYER_NAME_LEN);
 539 }
 540
 541 static void Handle_OP_PLAYER_CONNECTED()
 542 {
 543   struct NetworkClientPlayerInfo *player, *last_player = NULL;
 544   int new_client_nr = (int)buffer[0];
 545   int new_index_nr = new_client_nr - 1;
 546
 547   printf("OP_PLAYER_CONNECTED: %d\n", new_client_nr);
 548   Error(ERR_NETWORK_CLIENT, "new client %d connected", new_client_nr);
 549
 550   for (player = &first_player; player; player = player->next)
 551   {
 552     if (player->nr == new_client_nr)
 553       Error(ERR_EXIT, "multiplayer server sent duplicate player id");
 554
 555     last_player = player;
 556   }
 557
 558   last_player->next = player =
 559     checked_malloc(sizeof(struct NetworkClientPlayerInfo));
 560   player->nr = new_client_nr;
 561   player->name[0] = '\0';
 562   player->next = NULL;
 563
 564   stored_player[new_index_nr].connected_network = TRUE;
 565 }
 566
 567 static void Handle_OP_PLAYER_DISCONNECTED()
 568 {
 569   struct NetworkClientPlayerInfo *player, *player_disconnected;
 570   int player_nr = (int)buffer[0];
 571   int index_nr = player_nr - 1;
 572
 573   printf("OP_PLAYER_DISCONNECTED: %d\n", player_nr);
 574   player_disconnected = getNetworkPlayer(player_nr);
 575   Error(ERR_NETWORK_CLIENT, "client %d (%s) disconnected",
 576         player_nr, getNetworkPlayerName(buffer[0]));
 577
 578   for (player = &first_player; player; player = player->next)
 579     if (player->next == player_disconnected)
 580       player->next = player_disconnected->next;
 581   free(player_disconnected);
 582
 583   stored_player[index_nr].connected_locally = FALSE;
 584   stored_player[index_nr].connected_network = FALSE;
 585
 586   if (game_status == GAME_MODE_PLAYING)
 587   {
 588     char message[100];
 589
 590     sprintf(message, "Player %d left network server! Network game stopped!",
 591             player_nr);
 592
 593     Request(message, REQ_CONFIRM | REQ_STAY_CLOSED);
 594
 595     SetGameStatus(GAME_MODE_MAIN);
 596
 597     DrawMainMenu();
 598   }
 599   else if (game_status == GAME_MODE_MAIN)
 600   {
 601     DrawNetworkPlayers();
 602   }
 603 }
 604
 605 static void Handle_OP_START_PLAYING()
 606 {
 607   LevelDirTree *new_leveldir;
 608   int new_level_nr;
 609   unsigned int new_random_seed;
 610   char *new_leveldir_identifier;
 611
 612   new_level_nr = (buffer[2] << 8) + buffer[3];
 613   new_random_seed =
 614     (buffer[6] << 24) | (buffer[7] << 16) | (buffer[8] << 8) | (buffer[9]);
 615   new_leveldir_identifier = (char *)&buffer[10];
 616
 617   new_leveldir = getTreeInfoFromIdentifier(leveldir_first,
 618                                            new_leveldir_identifier);
 619   if (new_leveldir == NULL)
 620   {
 621     Error(ERR_WARN, "no such level identifier: '%s'", new_leveldir_identifier);
 622
 623     stop_network_game = TRUE;
 624
 625     return;
 626   }
 627
 628   printf("OP_START_PLAYING: %d\n", buffer[0]);
 629   Error(ERR_NETWORK_CLIENT,
 630         "client %d starts game [level %d from level identifier '%s']\n",
 631         buffer[0], new_level_nr, new_leveldir->identifier);
 632
 633   leveldir_current = new_leveldir;
 634   level_nr = new_level_nr;
 635
 636   TapeErase();
 637   LoadTape(level_nr);
 638   LoadLevel(level_nr);
 639
 640   StartGameActions(FALSE, setup.autorecord, new_random_seed);
 641 }
 642
 643 static void Handle_OP_PAUSE_PLAYING()
 644 {
 645   printf("OP_PAUSE_PLAYING: %d\n", buffer[0]);
 646   Error(ERR_NETWORK_CLIENT, "client %d pauses game", buffer[0]);
 647
 648   if (game_status == GAME_MODE_PLAYING)
 649   {
 650     tape.pausing = TRUE;
 651     DrawVideoDisplay(VIDEO_STATE_PAUSE_ON,0);
 652   }
 653 }
 654
 655 static void Handle_OP_CONTINUE_PLAYING()
 656 {
 657   printf("OP_CONTINUE_PLAYING: %d\n", buffer[0]);
 658   Error(ERR_NETWORK_CLIENT, "client %d continues game", buffer[0]);
 659
 660   if (game_status == GAME_MODE_PLAYING)
 661   {
 662     tape.pausing = FALSE;
 663     DrawVideoDisplay(VIDEO_STATE_PAUSE_OFF,0);
 664   }
 665 }
 666
 667 static void Handle_OP_STOP_PLAYING()
 668 {
 669   printf("OP_STOP_PLAYING: %d [%d]\n", buffer[0], buffer[2]);
 670   Error(ERR_NETWORK_CLIENT, "client %d stops game [%d]", buffer[0], buffer[2]);
 671
 672   if (game_status == GAME_MODE_PLAYING)
 673   {
 674     int client_nr = buffer[0];
 675     int index_nr = client_nr - 1;
 676     struct PlayerInfo *client_player = &stored_player[index_nr];
 677     boolean stopped_by_remote_player = (!client_player->connected_locally);
 678     char message[100];
 679
 680     sprintf(message, (buffer[2] == NETWORK_STOP_BY_PLAYER ?
 681                       "Network game stopped by player %d!" :
 682                       buffer[2] == NETWORK_STOP_BY_ERROR ?
 683                       "Network game stopped due to internal error!" :
 684                       "Network game stopped!"), client_nr);
 685
 686     if (buffer[2] != NETWORK_STOP_BY_PLAYER || stopped_by_remote_player)
 687       Request(message, REQ_CONFIRM | REQ_STAY_CLOSED);
 688
 689     SetGameStatus(GAME_MODE_MAIN);
 690
 691     DrawMainMenu();
 692   }
 693 }
 694
 695 static void Handle_OP_MOVE_PLAYER(unsigned int len)
 696 {
 697   int server_frame_counter;
 698   int i;
 699
 700   if (!network_playing)
 701     return;
 702
 703   server_frame_counter =
 704     (buffer[2] << 24) | (buffer[3] << 16) | (buffer[4] << 8) | (buffer[5]);
 705
 706   if (server_frame_counter != FrameCounter)
 707   {
 708     Error(ERR_INFO, "client and servers frame counters out of sync");
 709     Error(ERR_INFO, "frame counter of client is %d", FrameCounter);
 710     Error(ERR_INFO, "frame counter of server is %d", server_frame_counter);
 711     Error(ERR_INFO, "this should not happen -- please debug");
 712
 713     stop_network_game = TRUE;
 714
 715     return;
 716   }
 717
 718   /* copy valid player actions */
 719   for (i = 0; i < MAX_PLAYERS; i++)
 720     stored_player[i].effective_action =
 721       (i < len - 6 ? buffer[6 + i] : 0);
 722
 723   network_player_action_received = TRUE;
 724 }
 725
 726 static void HandleNetworkingMessages()
 727 {
 728   unsigned int message_length;
 729
 730   stop_network_game = FALSE;
 731
 732   while (nread >= 4 && nread >= 4 + readbuffer[3])
 733   {
 734     message_length = readbuffer[3];
 735     if (readbuffer[0] || readbuffer[1] || readbuffer[2])
 736       Error(ERR_EXIT, "wrong network server line length");
 737
 738     memcpy(buffer, &readbuffer[4], message_length);
 739     nread -= 4 + message_length;
 740     memmove(readbuffer, readbuffer + 4 + message_length, nread);
 741
 742     switch (buffer[1])
 743     {
 744       case OP_BAD_PROTOCOL_VERSION:
 745         Handle_OP_BAD_PROTOCOL_VERSION();
 746         break;
 747
 748       case OP_YOUR_NUMBER:
 749         Handle_OP_YOUR_NUMBER();
 750         break;
 751
 752       case OP_NUMBER_WANTED:
 753         Handle_OP_NUMBER_WANTED();
 754         break;
 755
 756       case OP_PLAYER_NAME:
 757         Handle_OP_PLAYER_NAME(message_length);
 758         break;
 759
 760       case OP_PLAYER_CONNECTED:
 761         Handle_OP_PLAYER_CONNECTED();
 762         break;
 763
 764       case OP_PLAYER_DISCONNECTED:
 765         Handle_OP_PLAYER_DISCONNECTED();
 766         break;
 767
 768       case OP_START_PLAYING:
 769         Handle_OP_START_PLAYING();
 770         break;
 771
 772       case OP_PAUSE_PLAYING:
 773         Handle_OP_PAUSE_PLAYING();
 774         break;
 775
 776       case OP_CONTINUE_PLAYING:
 777         Handle_OP_CONTINUE_PLAYING();
 778         break;
 779
 780       case OP_STOP_PLAYING:
 781         Handle_OP_STOP_PLAYING();
 782         break;
 783
 784       case OP_MOVE_PLAYER:
 785         Handle_OP_MOVE_PLAYER(message_length);
 786         break;
 787
 788       case OP_BROADCAST_MESSAGE:
 789         printf("OP_BROADCAST_MESSAGE: %d\n", buffer[0]);
 790         Error(ERR_NETWORK_CLIENT, "client %d sends message", buffer[0]);
 791         break;
 792     }
 793   }
 794
 795   fflush(stdout);
 796
 797   /* in case of internal error, stop network game */
 798   if (stop_network_game)
 799     SendToServer_StopPlaying(NETWORK_STOP_BY_ERROR);
 800 }
 801
 802 static char *HandleNetworkingPackets()
 803 {
 804   while (1)
 805   {
 806     /* ---------- check network server for activity ---------- */
 807
 808     int num_active_sockets = SDLNet_CheckSockets(rfds, 1);
 809
 810     if (num_active_sockets < 0)
 811       return "Error checking network sockets!";
 812
 813     if (num_active_sockets == 0)
 814       break;    // no active sockets, stop here
 815
 816     /* ---------- read packets from network server ---------- */
 817
 818     int num_bytes = SDLNet_TCP_Recv(sfd, readbuffer + nread, 1);
 819
 820     if (num_bytes < 0)
 821       return "Error reading from network server!";
 822
 823     if (num_bytes == 0)
 824       return "Connection to network server lost!";
 825
 826     nread += num_bytes;
 827
 828     HandleNetworkingMessages();
 829   }
 830
 831   return NULL;
 832 }
 833
 834 static void FreeNetworkClientPlayerInfo(struct NetworkClientPlayerInfo *player)
 835 {
 836   if (player == NULL)
 837     return;
 838
 839   if (player->next)
 840     FreeNetworkClientPlayerInfo(player->next);
 841
 842   checked_free(player);
 843 }
 844
 845 static void HandleNetworkingDisconnect()
 846 {
 847   int i;
 848
 849   SDLNet_TCP_DelSocket(rfds, sfd);
 850   SDLNet_TCP_Close(sfd);
 851
 852   network_playing = FALSE;
 853
 854   network.enabled = FALSE;
 855   network.connected = FALSE;
 856
 857   setup.network_mode = FALSE;
 858
 859   for (i = 0; i < MAX_PLAYERS; i++)
 860     stored_player[i].connected_network = FALSE;
 861
 862   FreeNetworkClientPlayerInfo(first_player.next);
 863
 864   first_player.nr = 0;
 865   first_player.next = NULL;
 866 }
 867
 868 void HandleNetworking()
 869 {
 870   char *error_message = HandleNetworkingPackets();
 871
 872   if (error_message != NULL)
 873   {
 874     HandleNetworkingDisconnect();
 875
 876     if (game_status == GAME_MODE_PLAYING)
 877     {
 878       Request(error_message, REQ_CONFIRM | REQ_STAY_CLOSED);
 879
 880       SetGameStatus(GAME_MODE_MAIN);
 881
 882       DrawMainMenu();
 883     }
 884     else
 885     {
 886       Request(error_message, REQ_CONFIRM);
 887
 888       if (game_status == GAME_MODE_MAIN)
 889         ClearNetworkPlayers();
 890     }
 891   }
 892 }
 893
 894 void DisconnectFromNetworkServer()
 895 {
 896   DrawNetworkText_Title("Terminating Network");
 897   DrawNetworkText("Disconnecting from network server ...");
 898
 899   HandleNetworkingDisconnect();
 900
 901   DrawNetworkText_Success("Successfully disconnected!");
 902
 903   /* short time to recognize result of network initialization */
 904   Delay_WithScreenUpdates(1000);
 905 }