X-Git-Url: https://git.artsoft.org/?a=blobdiff_plain;f=src%2Fnetwork.c;h=0e5955c62e103ebac1681c9f4ff9822437a77344;hb=fdbb975aee39b32064a9fdc461467e733c7854c9;hp=bb4ea67e6237ceaeed0ef3eb1322b4b4b45386d9;hpb=1cacebfb41c20889c904155001a5b88ace962348;p=rocksndiamonds.git

diff --git a/src/network.c b/src/network.c
index bb4ea67e..0e5955c6 100644
--- a/src/network.c
+++ b/src/network.c
@@ -1,587 +1,734 @@
-/***********************************************************
-*  Rocks'n'Diamonds -- McDuffin Strikes Back!              *
-*----------------------------------------------------------*
-*  (c) 1995-98 Artsoft Entertainment                       *
-*              Holger Schemel                              *
-*              Oststrasse 11a                              *
-*              33604 Bielefeld                             *
-*              phone: ++49 +521 290471                     *
-*              email: aeglos@valinor.owl.de                *
-*----------------------------------------------------------*
-*  network.c                                               *
-***********************************************************/
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
+// ============================================================================
+// Rocks'n'Diamonds - McDuffin Strikes Back!
+// ----------------------------------------------------------------------------
+// (c) 1995-2014 by Artsoft Entertainment
+//     		    Holger Schemel
+//		    info@artsoft.org
+//		    http://www.artsoft.org/
+// ----------------------------------------------------------------------------
+// network.c
+// ============================================================================
+
 #include <signal.h>
-#include <sys/types.h>
 #include <sys/time.h>
-#include <sys/wait.h>
-#include <sys/socket.h>
-#include <netinet/in.h>
-#include <netinet/tcp.h>
-#include <arpa/inet.h>
-#include <netdb.h>
-#include <errno.h>
+
+#include "libgame/libgame.h"
 
 #include "network.h"
 #include "netserv.h"
+#include "main.h"
 #include "game.h"
 #include "tape.h"
 #include "files.h"
 #include "tools.h"
-#include "misc.h"
-
-#define MAXNICKLEN 14
+#include "screens.h"
 
-struct user
+struct NetworkClientPlayerInfo
 {
   byte nr;
-  char name[MAXNICKLEN+2];
-  struct user *next;
+  char name[MAX_PLAYER_NAME_LEN + 1];
+  struct NetworkClientPlayerInfo *next;
 };
 
-struct user me =
+static struct NetworkClientPlayerInfo first_player =
 {
   0,
-  "no name",
+  EMPTY_PLAYER_NAME,
   NULL
 };
 
 /* server stuff */
 
-int sfd;
-unsigned char realbuf[512], readbuf[MAX_BUFFER_SIZE], writbuf[MAX_BUFFER_SIZE];
-unsigned char *buf = realbuf + 4;
-int nread = 0, nwrite = 0;
+static TCPsocket sfd;		/* TCP server socket */
+static UDPsocket udp;		/* UDP server socket */
+static SDLNet_SocketSet rfds;	/* socket set */
 
-void sysmsg(char *s)
+static byte realbuffer[512];
+static byte readbuffer[MAX_BUFFER_SIZE], writbuffer[MAX_BUFFER_SIZE];
+static byte *buffer = realbuffer + 4;
+static int nread = 0, nwrite = 0;
+static boolean stop_network_game = FALSE;
+
+static void SendBufferToServer(int size)
 {
-  if (verbose)
-  {
-    printf("** %s\n", s);
-    fflush(stdout);
-  }
+  if (!network.enabled)
+    return;
+
+  realbuffer[0] = realbuffer[1] = realbuffer[2] = 0;
+  realbuffer[3] = (byte)size;
+  buffer[0] = 0;
+
+  if (nwrite + 4 + size >= MAX_BUFFER_SIZE)
+    Error(ERR_EXIT, "internal error: network send buffer overflow");
+
+  memcpy(writbuffer + nwrite, realbuffer, 4 + size);
+  nwrite += 4 + size;
+
+  /* directly send the buffer to the network server */
+  SDLNet_TCP_Send(sfd, writbuffer, nwrite);
+  nwrite = 0;
 }
 
-void *mmalloc(int n)
+struct NetworkClientPlayerInfo *getNetworkPlayer(int player_nr)
 {
-  void *r;
+  struct NetworkClientPlayerInfo *player = NULL;
+
+  for (player = &first_player; player; player = player->next)
+    if (player->nr == player_nr)
+      break;
 
-  r = malloc(n);
-  if (r == NULL)
-    fatal("Out of memory");
-  return r;
+  if (player == NULL)	/* should not happen */
+    Error(ERR_EXIT, "protocol error: reference to non-existing player %d",
+	  player_nr);
+
+  return player;
 }
 
-void u_sleep(int i)
+char *getNetworkPlayerName(int player_nr)
 {
-  struct timeval tm;
-  tm.tv_sec = i / 1000000;
-  tm.tv_usec = i % 1000000;
-  select(0, NULL, NULL, NULL, &tm);
+  struct NetworkClientPlayerInfo *player;
+
+  if (player_nr == 0)
+    return("the network game server");
+  else if (player_nr == first_player.nr)
+    return("you");
+  else
+    for (player = &first_player; player; player = player->next)
+      if (player->nr == player_nr && strlen(player->name) > 0)
+	return(player->name);
+
+  return(EMPTY_PLAYER_NAME);
 }
 
-void flushbuf()
+static void StartNetworkServer(int port)
 {
-  if (nwrite)
-  {
-    write(sfd, writbuf, nwrite);
-    nwrite = 0;
-  }
+  static int p;
+
+  p = port;
+#if defined(TARGET_SDL2)
+  server_thread = SDL_CreateThread(NetworkServerThread,
+				   "NetworkServerThread", &p);
+#else
+  server_thread = SDL_CreateThread(NetworkServerThread, &p);
+#endif
+  network_server = TRUE;
 }
 
-void sendbuf(int len)
+boolean ConnectToServer(char *hostname, int port)
 {
-  if (!standalone)
-  {
-    realbuf[0] = realbuf[1] = realbuf[2] = 0;
-    realbuf[3] = (unsigned char)len;
-    buf[0] = 0;
-    if (nwrite + 4 + len >= MAX_BUFFER_SIZE)
-      fatal("Internal error: send buffer overflow");
-    memcpy(writbuf + nwrite, realbuf, 4 + len);
-    nwrite += 4 + len;
+  IPaddress ip;
+  int server_host = 0;
+  int i;
 
+  if (port == 0)
+    port = DEFAULT_SERVER_PORT;
 
-    flushbuf();
+  if (hostname == NULL)
+  {
+    // if no hostname given, try to auto-detect network server in local network
+    // by doing a UDP broadcast on the network server port and wait for answer
 
+    SDLNet_SocketSet udp_socket_set = SDLNet_AllocSocketSet(1);
+    if (!udp_socket_set)
+      Error(ERR_EXIT, "SDLNet_AllocSocketSet() failed: %s"), SDLNet_GetError();
 
-  }
-}
+    udp = SDLNet_UDP_Open(0);
+    if(!udp)
+      Error(ERR_EXIT, "SDLNet_UDP_Open() failed: %s", SDLNet_GetError());
 
-struct user *finduser(unsigned char c)
-{
-  struct user *u;
-
-  for (u = &me; u; u = u->next)
-    if (u->nr == c)
-      return u;
-  
-  fatal("Protocol error: reference to non-existing user");
-  return NULL; /* so that gcc -Wall doesn't complain */
-}
+    if (SDLNet_UDP_AddSocket(udp_socket_set, udp) == -1)
+      Error(ERR_EXIT_NETWORK_SERVER, "SDLNet_TCP_AddSocket() failed: %s"),
+        SDLNet_GetError();
 
-char *get_user_name(unsigned char c)
-{
-  struct user *u;
+    char *data_ptr = "network server UDB broadcast";
+    int data_len = strlen(data_ptr) + 1;
+    IPaddress ip_address;
 
-  if (c == 0)
-    return("the server");
-  else if (c == me.nr)
-    return("you");
-  else
-    for (u = &me; u; u = u->next)
-      if (u->nr == c && u->name && strlen(u->name))
-	return(u->name);
+    SDLNet_Write32(0xffffffff, &ip_address.host);	/* 255.255.255.255 */
+    SDLNet_Write16(port,       &ip_address.port);
 
-  return("no name");
-}
+    UDPpacket packet =
+    {
+      -1,
+      (Uint8 *)data_ptr,
+      data_len,
+      data_len,
+      0,
+      ip_address
+    };
 
-void InitNetworkServer(int port)
-{
-  switch (fork())
-  {
-    case 0:
-      NetworkServer(port, !serveronly);
+    SDLNet_UDP_Send(udp, -1, &packet);
 
-      /* never reached */
-      exit(0);
+    Error(ERR_DEBUG, "doing UDP broadcast for local network server ...");
 
-    case -1:
-      Error(ERR_RETURN,
-	    "cannot create network server process - no network games");
-      standalone = TRUE;
-      return;
+    if (SDLNet_CheckSockets(udp_socket_set, 1000) == 1)
+    {
+      int num_packets = SDLNet_UDP_Recv(udp, &packet);
+
+      if (num_packets == 1)
+      {
+        Error(ERR_DEBUG, "network server found");
 
-    default:
-      /* we are parent process -- resume normal operation */
-      return;
+        server_host = SDLNet_Read32(&packet.address.host);
+      }
+      else
+      {
+	Error(ERR_DEBUG, "no answer from network server");
+      }
+    }
+    else
+    {
+      Error(ERR_DEBUG, "no network server found");
+    }
   }
-}
 
-BOOL ConnectToServer(char *host, int port)
-{
-  struct hostent *hp;
-  struct sockaddr_in s;
-  struct protoent *tcpproto;
-  int on = 1, i;
+  rfds = SDLNet_AllocSocketSet(1);
 
-  if (host)
+  if (hostname)
   {
-    if ((s.sin_addr.s_addr = inet_addr(host)) == -1)
-    {
-      hp = gethostbyname(host);
-      if (!hp)
-	fatal("Host not found");
-      s.sin_addr = *(struct in_addr *)(hp->h_addr_list[0]);
-    }
+    SDLNet_ResolveHost(&ip, hostname, port);
+
+    if (ip.host == INADDR_NONE)
+      Error(ERR_EXIT, "cannot locate host '%s'", hostname);
+    else
+      server_host = SDLNet_Read32(&ip.host);
   }
   else
-    s.sin_addr.s_addr = inet_addr("127.0.0.1");
+  {
+    // if no hostname was given and no network server was auto-detected in the
+    // local network, try to connect to a network server at the local host
+    if (server_host == 0)
+      server_host = 0x7f000001;			/* 127.0.0.1 */
 
-  if (port == 0)
-    port = DEFAULTPORT;
+    SDLNet_Write32(server_host, &ip.host);
+    SDLNet_Write16(port,        &ip.port);
+  }
+
+  Error(ERR_DEBUG, "trying to connect to network server at %d.%d.%d.%d ...",
+        (server_host >> 24) & 0xff,
+        (server_host >> 16) & 0xff,
+        (server_host >>  8) & 0xff,
+        (server_host >>  0) & 0xff);
 
-  s.sin_port = htons(port);
-  s.sin_family = AF_INET;
-  sfd = socket(PF_INET, SOCK_STREAM, 0);
-  if (sfd < 0)
-    fatal("Out of file descriptors");
-  if ((tcpproto = getprotobyname("tcp")) != NULL)
-    setsockopt(sfd, tcpproto->p_proto, TCP_NODELAY, (char *)&on, sizeof(int));
+  sfd = SDLNet_TCP_Open(&ip);
 
-  if (connect(sfd, (struct sockaddr *)&s, sizeof(s)) < 0)
+  if (sfd)
   {
-    if (!host)
-    {
-      printf("No rocksndiamonds server on localhost - starting up one ...\n");
+    SDLNet_TCP_AddSocket(rfds, sfd);
+    return TRUE;
+  }
+  else
+  {
+    printf("SDLNet_TCP_Open(): %s\n", SDLNet_GetError());
+  }
 
-      InitNetworkServer(port);
+  if (hostname)			/* connect to specified server failed */
+    return FALSE;
 
-      for (i=0; i<6; i++)
-      {
-	u_sleep(500000);
-	close(sfd);
-	sfd = socket(PF_INET, SOCK_STREAM, 0);
-	if (sfd < 0)
-	  fatal("Out of file descriptors");
-	setsockopt(sfd, tcpproto->p_proto, TCP_NODELAY, (char *)&on, sizeof(int));
-	if (connect(sfd, (struct sockaddr *)&s, sizeof(s)) >= 0)
-	  break;
-      }
-      if (i==6)
-	fatal("Can't connect to server");
+  printf("No rocksndiamonds server on localhost -- starting up one ...\n");
+  StartNetworkServer(port);
+
+  /* wait for server to start up and try connecting several times */
+  for (i = 0; i < 6; i++)
+  {
+    Delay(500);			/* wait 500 ms == 0.5 seconds */
+
+    if ((sfd = SDLNet_TCP_Open(&ip)))		/* connected */
+    {
+      SDLNet_TCP_AddSocket(rfds, sfd);
+      return TRUE;
     }
-    else
-      fatal("Can't connect to server");
   }
 
-  return(TRUE);
+  /* when reaching this point, connect to newly started server has failed */
+  return FALSE;
 }
 
-void SendToServer_Nickname(char *nickname)
+void SendToServer_PlayerName(char *player_name)
 {
-  static char msgbuf[300];
+  int len_player_name = strlen(player_name);
 
-  buf[1] = OP_NICKNAME;
-  memcpy(&buf[2], nickname, strlen(nickname));
-  sendbuf(2 + strlen(nickname));
-  sprintf(msgbuf, "you set your nick to \"%s\"", nickname);
-  sysmsg(msgbuf);
+  buffer[1] = OP_PLAYER_NAME;
+  memcpy(&buffer[2], player_name, len_player_name);
+  SendBufferToServer(2 + len_player_name);
+  Error(ERR_NETWORK_CLIENT, "you set your player name to \"%s\"", player_name);
 }
 
 void SendToServer_ProtocolVersion()
 {
-  buf[1] = OP_PROTOCOL_VERSION;
-  buf[2] = PROT_VERS_1;
-  buf[3] = PROT_VERS_2;
-  buf[4] = PROT_VERS_3;
+  buffer[1] = OP_PROTOCOL_VERSION;
+  buffer[2] = PROTOCOL_VERSION_1;
+  buffer[3] = PROTOCOL_VERSION_2;
+  buffer[4] = PROTOCOL_VERSION_3;
 
-  sendbuf(5);
+  SendBufferToServer(5);
 }
 
 void SendToServer_NrWanted(int nr_wanted)
 {
-  buf[1] = OP_NUMBER_WANTED;
-  buf[2] = nr_wanted;
+  buffer[1] = OP_NUMBER_WANTED;
+  buffer[2] = nr_wanted;
 
-  sendbuf(3);
+  SendBufferToServer(3);
 }
 
 void SendToServer_StartPlaying()
 {
-  unsigned long new_random_seed = InitRND(NEW_RANDOMIZE);
+  unsigned int new_random_seed = InitRND(level.random_seed);
 
-  buf[1] = OP_START_PLAYING;
-  buf[2] = (byte)(level_nr >> 8);
-  buf[3] = (byte)(level_nr & 0xff);
-  buf[4] = (byte)(leveldir_nr >> 8);
-  buf[5] = (byte)(leveldir_nr & 0xff);
+  int dummy = 0;		/* !!! HAS NO MEANING ANYMORE !!! */
+				/* the name of the level must be enough */
 
-  buf[6] = (unsigned char)((new_random_seed >> 24) & 0xff);
-  buf[7] = (unsigned char)((new_random_seed >> 16) & 0xff);
-  buf[8] = (unsigned char)((new_random_seed >>  8) & 0xff);
-  buf[9] = (unsigned char)((new_random_seed >>  0) & 0xff);
+  buffer[1] = OP_START_PLAYING;
+  buffer[2] = (byte)(level_nr >> 8);
+  buffer[3] = (byte)(level_nr & 0xff);
+  buffer[4] = (byte)(dummy >> 8);
+  buffer[5] = (byte)(dummy & 0xff);
 
-  strcpy(&buf[10], leveldir[leveldir_nr].name);
+  buffer[6] = (unsigned char)((new_random_seed >> 24) & 0xff);
+  buffer[7] = (unsigned char)((new_random_seed >> 16) & 0xff);
+  buffer[8] = (unsigned char)((new_random_seed >>  8) & 0xff);
+  buffer[9] = (unsigned char)((new_random_seed >>  0) & 0xff);
 
-  sendbuf(10 + strlen(leveldir[leveldir_nr].name)+1);
+  strcpy((char *)&buffer[10], leveldir_current->identifier);
+
+  SendBufferToServer(10 + strlen(leveldir_current->identifier) + 1);
+}
+
+void SendToServer_PausePlaying()
+{
+  buffer[1] = OP_PAUSE_PLAYING;
+
+  SendBufferToServer(2);
+}
+
+void SendToServer_ContinuePlaying()
+{
+  buffer[1] = OP_CONTINUE_PLAYING;
+
+  SendBufferToServer(2);
+}
+
+void SendToServer_StopPlaying(int cause_for_stopping)
+{
+  buffer[1] = OP_STOP_PLAYING;
+  buffer[2] = cause_for_stopping;
+
+  SendBufferToServer(3);
 }
 
 void SendToServer_MovePlayer(byte player_action)
 {
-  buf[1] = OP_MOVE_FIGURE;
-  buf[2] = player_action;
+  buffer[1] = OP_MOVE_PLAYER;
+  buffer[2] = player_action;
+
+  SendBufferToServer(3);
+}
 
-  sendbuf(3);
+static void Handle_OP_BAD_PROTOCOL_VERSION()
+{
+  Error(ERR_WARN, "protocol version mismatch");
+  Error(ERR_EXIT, "server expects %d.%d.x instead of %d.%d.%d",
+	buffer[2], buffer[3],
+	PROTOCOL_VERSION_1, PROTOCOL_VERSION_2, PROTOCOL_VERSION_3);
 }
 
-void handlemessages()
+static void Handle_OP_YOUR_NUMBER()
 {
-  unsigned int len;
-  struct user *u, *v = NULL;
-  static char msgbuf[300];
+  int new_client_nr = buffer[2];
+  int new_index_nr = new_client_nr - 1;
+  struct PlayerInfo *old_local_player = local_player;
+  struct PlayerInfo *new_local_player = &stored_player[new_index_nr];
+
+  printf("OP_YOUR_NUMBER: %d\n", buffer[0]);
+  first_player.nr = new_client_nr;
 
-  while (nread >= 4 && nread >= 4 + readbuf[3])
+  if (old_local_player != new_local_player)
   {
-    len = readbuf[3];
-    if (readbuf[0] || readbuf[1] || readbuf[2])
-      fatal("Wrong server line length");
+    /* set relevant player settings and change to new player */
+
+    local_player = new_local_player;
 
-    memcpy(buf, &readbuf[4], len);
-    nread -= 4 + len;
-    copydown(readbuf, readbuf + 4 + len, nread);
+    old_local_player->connected_locally = FALSE;
+    new_local_player->connected_locally = TRUE;
 
-    switch(buf[1])
+    old_local_player->connected_network = FALSE;
+    new_local_player->connected_network = TRUE;
+  }
+
+  if (first_player.nr > MAX_PLAYERS)
+    Error(ERR_EXIT, "sorry, more than %d players not allowed", MAX_PLAYERS);
+
+  Error(ERR_NETWORK_CLIENT, "you get client # %d", new_client_nr);
+}
+
+static void Handle_OP_NUMBER_WANTED()
+{
+  int client_nr_wanted = buffer[2];
+  int old_client_nr = buffer[0];
+  int new_client_nr = buffer[3];
+  int old_index_nr = old_client_nr - 1;
+  int new_index_nr = new_client_nr - 1;
+  int index_nr_wanted = client_nr_wanted - 1;
+  struct PlayerInfo *old_player = &stored_player[old_index_nr];
+  struct PlayerInfo *new_player = &stored_player[new_index_nr];
+
+  printf("OP_NUMBER_WANTED: %d\n", buffer[0]);
+
+  if (new_client_nr == client_nr_wanted)	/* switching succeeded */
+  {
+    struct NetworkClientPlayerInfo *player;
+
+    if (old_client_nr != client_nr_wanted)	/* client's nr has changed */
+      Error(ERR_NETWORK_CLIENT, "client %d switches to # %d",
+	    old_client_nr, new_client_nr);
+    else if (old_client_nr == first_player.nr)	/* local player keeps his nr */
+      Error(ERR_NETWORK_CLIENT, "keeping client # %d", new_client_nr);
+
+    if (old_client_nr != new_client_nr)
     {
-      case OP_YOUR_NUMBER:
-      {
-	int new_client_nr = buf[2];
-	int new_index_nr = new_client_nr - 1;
+      /* set relevant player settings and change to new player */
 
-	printf("OP_YOUR_NUMBER: %d\n", buf[0]);
-	me.nr = new_client_nr;
+      old_player->connected_network = FALSE;
+      new_player->connected_network = TRUE;
+    }
 
-	stored_player[new_index_nr] = *local_player;
-	local_player = &stored_player[new_index_nr];
+    player = getNetworkPlayer(old_client_nr);
+    player->nr = new_client_nr;
 
-	TestPlayer = new_index_nr;
+    if (old_player == local_player)		/* local player switched */
+    {
+      local_player = new_player;
 
-	if (me.nr > MAX_PLAYERS)
-	  Error(ERR_EXIT, "sorry - no more than %d players", MAX_PLAYERS);
+      old_player->connected_locally = FALSE;
+      new_player->connected_locally = TRUE;
+    }
+  }
+  else if (old_client_nr == first_player.nr)	/* failed -- local player? */
+  {
+    char request[100];
 
-	sprintf(msgbuf, "you get client # %d", new_client_nr);
-	sysmsg(msgbuf);
+    sprintf(request, "Sorry! Player %d already exists! You are player %d!",
+	    index_nr_wanted + 1, new_index_nr + 1);
 
-	break;
-      }
+    Request(request, REQ_CONFIRM);
 
-      case OP_NUMBER_WANTED:
-      {
-	int client_nr_wanted = buf[2];
-	int new_client_nr = buf[3];
-	int new_index_nr = new_client_nr - 1;
+    Error(ERR_NETWORK_CLIENT, "cannot switch -- you keep client # %d",
+	  new_client_nr);
+  }
+}
 
-	printf("OP_NUMBER_WANTED: %d\n", buf[0]);
+static void Handle_OP_PLAYER_NAME(unsigned int len)
+{
+  struct NetworkClientPlayerInfo *player;
+  int player_nr = (int)buffer[0];
+
+  printf("OP_PLAYER_NAME: %d\n", player_nr);
+  player = getNetworkPlayer(player_nr);
+  buffer[len] = 0;
+  Error(ERR_NETWORK_CLIENT, "client %d calls itself \"%s\"",
+	buffer[0], &buffer[2]);
+  strncpy(player->name, (char *)&buffer[2], MAX_PLAYER_NAME_LEN);
+}
 
-	if (new_client_nr != client_nr_wanted)
-	{
-	  char *color[] = { "yellow", "red", "green", "blue" };
+static void Handle_OP_PLAYER_CONNECTED()
+{
+  struct NetworkClientPlayerInfo *player, *last_player = NULL;
+  int new_client_nr = (int)buffer[0];
+  int new_index_nr = new_client_nr - 1;
 
-	  sprintf(msgbuf, "Sorry ! You are %s player !",
-		  color[new_index_nr]);
-	  Request(msgbuf, REQ_CONFIRM);
+  printf("OP_PLAYER_CONNECTED: %d\n", new_client_nr);
+  Error(ERR_NETWORK_CLIENT, "new client %d connected", new_client_nr);
 
-	  sprintf(msgbuf, "cannot switch -- you keep client # %d",
-		  new_client_nr);
-	  sysmsg(msgbuf);
-	}
-	else
-	{
-	  if (me.nr != client_nr_wanted)
-	    sprintf(msgbuf, "switching to client # %d", new_client_nr);
-	  else
-	    sprintf(msgbuf, "keeping client # %d", new_client_nr);
-	  sysmsg(msgbuf);
+  for (player = &first_player; player; player = player->next)
+  {
+    if (player->nr == new_client_nr)
+      Error(ERR_EXIT, "multiplayer server sent duplicate player id");
 
-	  me.nr = new_client_nr;
+    last_player = player;
+  }
 
-	  stored_player[new_index_nr] = *local_player;
-	  local_player = &stored_player[new_index_nr];
+  last_player->next = player =
+    checked_malloc(sizeof(struct NetworkClientPlayerInfo));
+  player->nr = new_client_nr;
+  player->name[0] = '\0';
+  player->next = NULL;
 
-	  TestPlayer = new_index_nr;
-	}
+  stored_player[new_index_nr].connected_network = TRUE;
+}
 
-	break;
-      }
+static void Handle_OP_PLAYER_DISCONNECTED()
+{
+  struct NetworkClientPlayerInfo *player, *player_disconnected;
+  int player_nr = (int)buffer[0];
+  int index_nr = player_nr - 1;
+
+  printf("OP_PLAYER_DISCONNECTED: %d\n", player_nr);
+  player_disconnected = getNetworkPlayer(player_nr);
+  Error(ERR_NETWORK_CLIENT, "client %d (%s) disconnected",
+	player_nr, getNetworkPlayerName(buffer[0]));
+
+  for (player = &first_player; player; player = player->next)
+    if (player->next == player_disconnected)
+      player->next = player_disconnected->next;
+  free(player_disconnected);
+
+  stored_player[index_nr].connected_locally = FALSE;
+  stored_player[index_nr].connected_network = FALSE;
+}
 
-      case OP_PLAYER_CONNECTED:
-	printf("OP_PLAYER_CONNECTED: %d\n", buf[0]);
-	sprintf(msgbuf, "new client %d connected", buf[0]);
-	sysmsg(msgbuf);
-
-	for (u = &me; u; u = u->next)
-	{
-	  if (u->nr == buf[0])
-	    Error(ERR_EXIT, "multiplayer server sent duplicate player id");
-	  else
-	    v = u;
-	}
-
-	v->next = u = mmalloc(sizeof(struct user));
-	u->nr = buf[0];
-	u->name[0] = '\0';
-	u->next = NULL;
+static void Handle_OP_START_PLAYING()
+{
+  LevelDirTree *new_leveldir;
+  int new_level_nr;
+  unsigned int new_random_seed;
+  char *new_leveldir_identifier;
+
+  new_level_nr = (buffer[2] << 8) + buffer[3];
+  new_random_seed =
+    (buffer[6] << 24) | (buffer[7] << 16) | (buffer[8] << 8) | (buffer[9]);
+  new_leveldir_identifier = (char *)&buffer[10];
+
+  new_leveldir = getTreeInfoFromIdentifier(leveldir_first,
+					   new_leveldir_identifier);
+  if (new_leveldir == NULL)
+  {
+    Error(ERR_WARN, "no such level identifier: '%s'", new_leveldir_identifier);
 
-	break;
+    new_leveldir = leveldir_first;
+    Error(ERR_WARN, "using default level set: '%s'", new_leveldir->identifier);
+  }
 
-      case OP_NICKNAME:
-	printf("OP_NICKNAME: %d\n", buf[0]);
-	u = finduser(buf[0]);
-	buf[len] = 0;
-	sprintf(msgbuf, "client %d calls itself \"%s\"", buf[0], &buf[2]);
-	sysmsg(msgbuf);
-	strncpy(u->name, &buf[2], MAXNICKLEN);
-	break;
-      
-      case OP_GONE:
-	printf("OP_GONE: %d\n", buf[0]);
-	u = finduser(buf[0]);
-	sprintf(msgbuf, "client %d (%s) disconnected",
-		buf[0], get_user_name(buf[0]));
-	sysmsg(msgbuf);
-
-	for (v = &me; v; v = v->next)
-	  if (v->next == u)
-	    v->next = u->next;
-	free(u);
+  printf("OP_START_PLAYING: %d\n", buffer[0]);
+  Error(ERR_NETWORK_CLIENT,
+	"client %d starts game [level %d from level identifier '%s']\n",
+	buffer[0], new_level_nr, new_leveldir->identifier);
 
-	break;
+  leveldir_current = new_leveldir;
+  level_nr = new_level_nr;
 
-      case OP_BAD_PROTOCOL_VERSION:
-	Error(ERR_RETURN, "protocol version mismatch");
-	Error(ERR_EXIT, "server expects %d.%d.x instead of %d.%d.%d",
-	      buf[2], buf[3], PROT_VERS_1, PROT_VERS_2, PROT_VERS_3);
-	break;
+  TapeErase();
+  LoadTape(level_nr);
+  LoadLevel(level_nr);
 
-      case OP_START_PLAYING:
-      {
-	int new_level_nr, new_leveldir_nr;
-	unsigned long new_random_seed;
-	unsigned char *new_leveldir_name;
+  StartGameActions(FALSE, setup.autorecord, new_random_seed);
+}
 
-	/*
-	if (game_status == PLAYING)
-	  break;
-	*/
+static void Handle_OP_PAUSE_PLAYING()
+{
+  printf("OP_PAUSE_PLAYING: %d\n", buffer[0]);
+  Error(ERR_NETWORK_CLIENT, "client %d pauses game", buffer[0]);
 
-	new_level_nr = (buf[2] << 8) + buf[3];
-	new_leveldir_nr = (buf[4] << 8) + buf[5];
-	new_random_seed =
-	  (buf[6] << 24) | (buf[7] << 16) | (buf[8] << 8) | (buf[9]);
-	new_leveldir_name = &buf[10];
+  tape.pausing = TRUE;
+  DrawVideoDisplay(VIDEO_STATE_PAUSE_ON,0);
+}
 
-	printf("OP_START_PLAYING: %d\n", buf[0]);
-	sprintf(msgbuf, "client %d starts game [level %d from levedir %d (%s)]\n",
-		buf[0],
-		new_level_nr,
-		new_leveldir_nr,
-		new_leveldir_name);
-	sysmsg(msgbuf);
+static void Handle_OP_CONTINUE_PLAYING()
+{
+  printf("OP_CONTINUE_PLAYING: %d\n", buffer[0]);
+  Error(ERR_NETWORK_CLIENT, "client %d continues game", buffer[0]);
 
+  tape.pausing = FALSE;
+  DrawVideoDisplay(VIDEO_STATE_PAUSE_OFF,0);
+}
 
-	if (strcmp(leveldir[new_leveldir_nr].name, new_leveldir_name) != 0)
-	  Error(ERR_RETURN, "no such level directory: '%s'",new_leveldir_name);
+static void Handle_OP_STOP_PLAYING()
+{
+  printf("OP_STOP_PLAYING: %d [%d]\n", buffer[0], buffer[2]);
+  Error(ERR_NETWORK_CLIENT, "client %d stops game [%d]", buffer[0], buffer[2]);
 
-	leveldir_nr = new_leveldir_nr;
+  if (game_status == GAME_MODE_PLAYING)
+  {
+    int client_nr = buffer[0];
+    int index_nr = client_nr - 1;
+    boolean stopped_by_remote_player = (index_nr != local_player->index_nr);
+    char *message = (buffer[2] == NETWORK_STOP_BY_PLAYER ?
+		     "Network game stopped by player!" :
+		     buffer[2] == NETWORK_STOP_BY_ERROR ?
+		     "Network game stopped due to internal error!" :
+		     "Network game stopped!");
+
+    if (buffer[2] != NETWORK_STOP_BY_PLAYER || stopped_by_remote_player)
+      Request(message, REQ_CONFIRM | REQ_STAY_CLOSED);
+  }
 
-	local_player->leveldir_nr = leveldir_nr;
-	LoadPlayerInfo(PLAYER_LEVEL);
-	SavePlayerInfo(PLAYER_SETUP);
+  SetGameStatus(GAME_MODE_MAIN);
 
-	level_nr = new_level_nr;
+  DrawMainMenu();
+}
 
-	TapeErase();
-	LoadLevelTape(level_nr);
+static void Handle_OP_MOVE_PLAYER(unsigned int len)
+{
+  int server_frame_counter;
+  int i;
 
-	GetPlayerConfig();
-	LoadLevel(level_nr);
+  if (!network_playing)
+    return;
 
-	/*
-	if (autorecord_on)
-	  TapeStartRecording();
-	*/
+  server_frame_counter =
+    (buffer[2] << 24) | (buffer[3] << 16) | (buffer[4] << 8) | (buffer[5]);
 
-	if (tape.recording)
-	  tape.random_seed = new_random_seed;
+  if (server_frame_counter != FrameCounter)
+  {
+    Error(ERR_INFO, "client and servers frame counters out of sync");
+    Error(ERR_INFO, "frame counter of client is %d", FrameCounter);
+    Error(ERR_INFO, "frame counter of server is %d", server_frame_counter);
+    Error(ERR_INFO, "this should not happen -- please debug");
 
-	InitRND(new_random_seed);
+    stop_network_game = TRUE;
 
+    return;
+  }
 
-	/*
-	printf("tape.random_seed == %d\n", tape.random_seed);
-	*/
+  /* copy valid player actions */
+  for (i = 0; i < MAX_PLAYERS; i++)
+    stored_player[i].effective_action =
+      (i < len - 6 ? buffer[6 + i] : 0);
 
-	game_status = PLAYING;
-	InitGame();
+  network_player_action_received = TRUE;
+}
 
-	break;
-      }
+static void HandleNetworkingMessages()
+{
+  unsigned int message_length;
 
-      case OP_MOVE_FIGURE:
-      {
-	int frame_nr;
-	int i;
+  stop_network_game = FALSE;
 
-	frame_nr =
-	  (buf[2] << 24) | (buf[3] << 16) | (buf[4] << 8) | (buf[5]);
+  while (nread >= 4 && nread >= 4 + readbuffer[3])
+  {
+    message_length = readbuffer[3];
+    if (readbuffer[0] || readbuffer[1] || readbuffer[2])
+      Error(ERR_EXIT, "wrong network server line length");
 
-	if (frame_nr != FrameCounter)
-	{
-	  Error(ERR_RETURN, "client and servers frame counters out of sync");
-	  Error(ERR_RETURN, "frame counter of client is %d", FrameCounter);
-	  Error(ERR_RETURN, "frame counter of server is %d", frame_nr);
-	  Error(ERR_EXIT,   "this should not happen -- please debug");
-	}
+    memcpy(buffer, &readbuffer[4], message_length);
+    nread -= 4 + message_length;
+    memmove(readbuffer, readbuffer + 4 + message_length, nread);
 
-	for (i=0; i<MAX_PLAYERS; i++)
-	{
-	  if (stored_player[i].active)
-	    network_player_action[i] = buf[6 + i];
-	}
+    switch (buffer[1])
+    {
+      case OP_BAD_PROTOCOL_VERSION:
+	Handle_OP_BAD_PROTOCOL_VERSION();
+	break;
 
-	network_player_action_received = TRUE;
+      case OP_YOUR_NUMBER:
+	Handle_OP_YOUR_NUMBER();
+	break;
 
-	sprintf(msgbuf, "frame %d: client %d moves player [0x%02x]",
-		FrameCounter, buf[0], buf[2]);
-	sysmsg(msgbuf);
+      case OP_NUMBER_WANTED:
+	Handle_OP_NUMBER_WANTED();
+	break;
 
+      case OP_PLAYER_NAME:
+	Handle_OP_PLAYER_NAME(message_length);
 	break;
-      }
 
-      case OP_PAUSE:
-	printf("OP_PAUSE: %d\n", buf[0]);
-	sprintf(msgbuf, "client %d pauses game", buf[0]);
-	sysmsg(msgbuf);
+      case OP_PLAYER_CONNECTED:
+	Handle_OP_PLAYER_CONNECTED();
+	break;
+      
+      case OP_PLAYER_DISCONNECTED:
+	Handle_OP_PLAYER_DISCONNECTED();
 	break;
 
-      case OP_CONT:
-	printf("OP_CONT: %d\n", buf[0]);
-	sprintf(msgbuf, "client %d continues game", buf[0]);
-	sysmsg(msgbuf);
+      case OP_START_PLAYING:
+	Handle_OP_START_PLAYING();
 	break;
 
-      case OP_WON:
-	printf("OP_WON: %d\n", buf[0]);
-	sprintf(msgbuf, "client %d wins the game", buf[0]);
-	sysmsg(msgbuf);
+      case OP_PAUSE_PLAYING:
+	Handle_OP_PAUSE_PLAYING();
 	break;
 
-      case OP_ZERO:
-	printf("OP_ZERO: %d\n", buf[0]);
-	sprintf(msgbuf, "client %d resets game counters", buf[0]);
-	sysmsg(msgbuf);
+      case OP_CONTINUE_PLAYING:
+	Handle_OP_CONTINUE_PLAYING();
 	break;
 
-      case OP_MSG:
-	printf("OP_MSG: %d\n", buf[0]);
-	sprintf(msgbuf, "client %d sends message", buf[0]);
+      case OP_STOP_PLAYING:
+	Handle_OP_STOP_PLAYING();
 	break;
-      
-      case OP_LOST:
-	printf("OP_MSG: %d\n", buf[0]);
-	sprintf(msgbuf, "client %d has lost", buf[0]);
+
+      case OP_MOVE_PLAYER:
+	Handle_OP_MOVE_PLAYER(message_length);
 	break;
-      
-      case OP_LEVEL:
-	printf("OP_MSG: %d\n", buf[0]);
-	sprintf(msgbuf, "client %d sets level to %d", buf[0], buf[2]);
+
+      case OP_BROADCAST_MESSAGE:
+	printf("OP_BROADCAST_MESSAGE: %d\n", buffer[0]);
+	Error(ERR_NETWORK_CLIENT, "client %d sends message", buffer[0]);
 	break;
     }
   }
 
   fflush(stdout);
+
+  /* in case of internal error, stop network game */
+  if (stop_network_game)
+    SendToServer_StopPlaying(NETWORK_STOP_BY_ERROR);
 }
 
-void HandleNetworking()
+static char *HandleNetworkingPackets()
 {
-  static struct timeval tv = { 0, 0 };
-  fd_set rfds;
-  int r = 0;
+  while (1)
+  {
+    /* ---------- check network server for activity ---------- */
 
-  if (standalone)
-    return;
+    int num_active_sockets = SDLNet_CheckSockets(rfds, 1);
 
-  flushbuf();
+    if (num_active_sockets < 0)
+      return "Error checking network sockets!";
 
-  FD_ZERO(&rfds);
-  FD_SET(sfd, &rfds);
+    if (num_active_sockets == 0)
+      break;	// no active sockets, stop here
 
-  r = select(sfd + 1, &rfds, NULL, NULL, &tv);
+    /* ---------- read packets from network server ---------- */
 
-  if (r < 0 && errno != EINTR)
-  {
-    perror("select");
-    fatal("fatal: select() failed");
+    int num_bytes = SDLNet_TCP_Recv(sfd, readbuffer + nread, 1);
+
+    if (num_bytes < 0)
+      return "Error reading from network server!";
+
+    if (num_bytes == 0)
+      return "Connection to network server lost!";
+
+    nread += num_bytes;
+
+    HandleNetworkingMessages();
   }
 
-  if (r < 0)
-    FD_ZERO(&rfds);
+  return NULL;
+}
+
+static void HandleNetworkingDisconnect()
+{
+  int i;
+
+  SDLNet_TCP_DelSocket(rfds, sfd);
+  SDLNet_TCP_Close(sfd);
 
-  if (FD_ISSET(sfd, &rfds))
+  network.enabled = FALSE;
+  network_playing = FALSE;
+
+  for (i = 0; i < MAX_PLAYERS; i++)
+    stored_player[i].connected_network = FALSE;
+}
+
+void HandleNetworking()
+{
+  char *error_message = HandleNetworkingPackets();
+
+  if (error_message != NULL)
   {
-    int r;
+    HandleNetworkingDisconnect();
 
-    r = read(sfd, readbuf + nread, MAX_BUFFER_SIZE - nread);
+    if (game_status == GAME_MODE_PLAYING)
+    {
+      Request(error_message, REQ_CONFIRM | REQ_STAY_CLOSED);
 
-    if (r < 0)
-      fatal("Error reading from server");
-    if (r == 0)
-      fatal("Connection to server lost");
-    nread += r;
+      SetGameStatus(GAME_MODE_MAIN);
 
-    handlemessages();
+      DrawMainMenu();
+    }
+    else
+    {
+      Request(error_message, REQ_CONFIRM);
+    }
   }
 }