ref: 92b3eeba514afec641892ecb090356027156f9ee
dir: /src/net_server.c/
// Emacs style mode select -*- C++ -*-
//-----------------------------------------------------------------------------
//
// $Id: net_server.c 323 2006-01-22 22:29:42Z fraggle $
//
// Copyright(C) 2005 Simon Howard
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
// 02111-1307, USA.
//
// $Log$
// Revision 1.23 2006/01/22 22:29:42 fraggle
// Periodically request the time from clients to estimate their offset to
// the server time.
//
// Revision 1.22 2006/01/21 14:16:49 fraggle
// Add first game data sending code. Check the client version when connecting.
//
// Revision 1.21 2006/01/12 02:18:59 fraggle
// Only start new games when in the waiting-for-start state.
//
// Revision 1.20 2006/01/12 02:11:52 fraggle
// Game start packets
//
// Revision 1.19 2006/01/10 19:59:26 fraggle
// Reliable packet transport mechanism
//
// Revision 1.18 2006/01/09 02:03:39 fraggle
// Send clients their player number, and indicate on the waiting screen
// which client we are.
//
// Revision 1.17 2006/01/09 01:50:51 fraggle
// Deduce a sane player name by examining environment variables. Add
// a "player_name" setting to chocolate-doom.cfg. Transmit the name
// to the server and use the names players send in the waiting data list.
//
// Revision 1.16 2006/01/08 05:06:06 fraggle
// Reject new connections if the server is not in the waiting state.
//
// Revision 1.15 2006/01/08 04:52:26 fraggle
// Allow the server to reject clients
//
// Revision 1.14 2006/01/08 03:36:17 fraggle
// Fix packet send
//
// Revision 1.13 2006/01/08 02:53:05 fraggle
// Send keepalives if the connection is not doing anything else.
// Send all packets using a new NET_Conn_SendPacket to support this.
//
// Revision 1.12 2006/01/08 00:10:48 fraggle
// Move common connection code into net_common.c, shared by server
// and client code.
//
// Revision 1.11 2006/01/07 20:08:11 fraggle
// Send player name and address in the waiting data packets. Display these
// on the waiting screen, and improve the waiting screen appearance.
//
// Revision 1.10 2006/01/02 21:48:37 fraggle
// fix client connected function
//
// Revision 1.9 2006/01/02 21:04:10 fraggle
// Create NET_SV_Shutdown function to shut down the server. Call it
// when quitting the game. Print the IP of the server correctly when
// connecting.
//
// Revision 1.8 2006/01/02 20:13:06 fraggle
// Refer to connected clients by their AddrToString() output rather than just
// the pointer to their struct. Listen for IP connections as well as
// loopback connections.
//
// Revision 1.7 2006/01/02 17:24:40 fraggle
// Remove test code
//
// Revision 1.6 2006/01/02 00:54:17 fraggle
// Fix packet not freed back after being sent.
// Code to disconnect clients from the server side.
//
// Revision 1.5 2006/01/02 00:00:08 fraggle
// Neater prefixes: NET_Client -> NET_CL_. NET_Server -> NET_SV_.
//
// Revision 1.4 2006/01/01 23:54:31 fraggle
// Client disconnect code
//
// Revision 1.3 2005/12/30 18:58:22 fraggle
// Fix client code to correctly send reply to server on connection.
// Add "waiting screen" while waiting for the game to start.
// Hook in the new networking code into the main game code.
//
// Revision 1.2 2005/12/29 21:29:55 fraggle
// Working client connect code
//
// Revision 1.1 2005/12/29 17:48:25 fraggle
// Add initial client/server connect code. Reorganise sources list in
// Makefile.am.
//
//
// Network server code
//
#include <stdlib.h>
#include <string.h>
#include "config.h"
#include "doomdef.h"
#include "doomstat.h"
#include "i_system.h"
#include "net_client.h"
#include "net_common.h"
#include "net_defs.h"
#include "net_io.h"
#include "net_loop.h"
#include "net_packet.h"
#include "net_server.h"
#include "net_sdl.h"
#include "net_structrw.h"
typedef enum
{
// waiting for the game to start
SERVER_WAITING_START,
// in a game
SERVER_IN_GAME,
} net_server_state_t;
typedef struct
{
boolean active;
net_addr_t *addr;
net_connection_t connection;
int last_send_time;
char *name;
// time query variables
int last_time_req_time;
int time_req_seq;
signed int time_offset;
} net_client_t;
static net_server_state_t server_state;
static boolean server_initialised = false;
static net_client_t clients[MAXNETNODES];
static net_context_t *server_context;
static int sv_gamemode;
static int sv_gamemission;
static net_gamesettings_t sv_settings;
static void NET_SV_DisconnectClient(net_client_t *client)
{
if (client->active)
{
NET_Conn_Disconnect(&client->connection);
}
}
static boolean ClientConnected(net_client_t *client)
{
// Check that the client is properly connected: ie. not in the
// process of connecting or disconnecting
return client->active
&& client->connection.state == NET_CONN_STATE_CONNECTED;
}
// returns the number of clients connected
static int NET_SV_NumClients(void)
{
int count;
int i;
count = 0;
for (i=0; i<MAXNETNODES; ++i)
{
if (ClientConnected(&clients[i]))
{
++count;
}
}
return count;
}
// Returns the index of a particular client in the list of connected
// clients.
static int NET_SV_ClientIndex(net_client_t *client)
{
int count;
int i;
count = 0;
for (i=0; i<MAXNETNODES; ++i)
{
if (ClientConnected(&clients[i]))
{
if (client == &clients[i])
{
return count;
}
++count;
}
}
return -1;
}
// returns a pointer to the client which controls the server
static net_client_t *NET_SV_Controller(void)
{
int i;
// first client in the list is the controller
for (i=0; i<MAXNETNODES; ++i)
{
if (ClientConnected(&clients[i]))
{
return &clients[i];
}
}
return NULL;
}
// Given an address, find the corresponding client
static net_client_t *NET_SV_FindClient(net_addr_t *addr)
{
int i;
for (i=0; i<MAXNETNODES; ++i)
{
if (clients[i].active && clients[i].addr == addr)
{
// found the client
return &clients[i];
}
}
return NULL;
}
// send a rejection packet to a client
static void NET_SV_SendReject(net_addr_t *addr, char *msg)
{
net_packet_t *packet;
packet = NET_NewPacket(10);
NET_WriteInt16(packet, NET_PACKET_TYPE_REJECTED);
NET_WriteString(packet, msg);
NET_SendPacket(addr, packet);
NET_FreePacket(packet);
}
// parse a SYN from a client(initiating a connection)
static void NET_SV_ParseSYN(net_packet_t *packet,
net_client_t *client,
net_addr_t *addr)
{
unsigned int magic;
unsigned int cl_gamemode, cl_gamemission;
char *player_name;
char *client_version;
int i;
// read the magic number
if (!NET_ReadInt32(packet, &magic))
{
return;
}
if (magic != NET_MAGIC_NUMBER)
{
// invalid magic number
return;
}
// read the game mode and mission
if (!NET_ReadInt16(packet, &cl_gamemode)
|| !NET_ReadInt16(packet, &cl_gamemission))
{
return;
}
// read the player's name
player_name = NET_ReadString(packet);
if (player_name == NULL)
{
return;
}
client_version = NET_ReadString(packet);
if (client_version == NULL)
{
return;
}
// received a valid SYN
// not accepting new connections?
if (server_state != SERVER_WAITING_START)
{
NET_SV_SendReject(addr, "Server is not currently accepting connections");
}
// allocate a client slot if there isn't one already
if (client == NULL)
{
// find a slot, or return if none found
for (i=0; i<MAXNETNODES; ++i)
{
if (!clients[i].active)
{
client = &clients[i];
break;
}
}
if (client == NULL)
{
return;
}
}
else
{
// If this is a recently-disconnected client, deactivate
// to allow immediate reconnection
if (client->connection.state == NET_CONN_STATE_DISCONNECTED)
{
client->active = false;
}
}
// New client?
if (!client->active)
{
int num_clients;
// Before accepting a new client, check that there is a slot
// free
num_clients = NET_SV_NumClients();
if (num_clients >= MAXPLAYERS)
{
NET_SV_SendReject(addr, "Server is full!");
return;
}
if (strcmp(client_version, PACKAGE_STRING) != 0)
{
NET_SV_SendReject(addr, "Different versions cannot play a network game!");
return;
}
// Adopt the game mode and mission of the first connecting client
if (num_clients == 0)
{
sv_gamemode = cl_gamemode;
sv_gamemission = cl_gamemission;
}
// Check the connecting client is playing the same game as all
// the other clients
if (cl_gamemode != sv_gamemode || cl_gamemission != sv_gamemission)
{
NET_SV_SendReject(addr, "You are playing the wrong game!");
return;
}
// Activate, initialise connection
client->active = true;
NET_Conn_InitServer(&client->connection, addr);
client->addr = addr;
client->last_send_time = -1;
client->name = strdup(player_name);
client->last_time_req_time = -1;
client->time_req_seq = 0;
client->time_offset = 0;
}
if (client->connection.state == NET_CONN_STATE_WAITING_ACK)
{
// force an acknowledgement
client->connection.last_send_time = -1;
}
}
// Parse a game start packet
static void NET_SV_ParseGameStart(net_packet_t *packet, net_client_t *client)
{
net_gamesettings_t settings;
net_packet_t *startpacket;
int i;
if (client != NET_SV_Controller())
{
// Only the controller can start a new game
return;
}
if (!NET_ReadSettings(packet, &settings))
{
// Malformed packet
return;
}
if (server_state != SERVER_WAITING_START)
{
// Can only start a game if we are in the waiting start state.
return;
}
// Change server state
server_state = SERVER_IN_GAME;
sv_settings = settings;
// Send start packets to each connected node
for (i=0; i<MAXNETNODES; ++i)
{
if (ClientConnected(&clients[i]))
{
startpacket = NET_Conn_NewReliable(&clients[i].connection,
NET_PACKET_TYPE_GAMESTART);
NET_WriteInt8(startpacket, NET_SV_NumClients());
NET_WriteInt8(startpacket, NET_SV_ClientIndex(&clients[i]));
NET_WriteSettings(startpacket, &settings);
}
}
}
static void NET_SV_ParseTimeResponse(net_packet_t *packet, net_client_t *client)
{
unsigned int seq;
unsigned int remote_time;
unsigned int rtt;
unsigned int nowtime;
signed int time_offset;
if (!NET_ReadInt32(packet, &seq)
|| !NET_ReadInt32(packet, &remote_time))
{
return;
}
if (seq != client->time_req_seq)
{
// Not the time response we are expecting
return;
}
// Calculate the round trip time
nowtime = I_GetTimeMS();
rtt = nowtime - client->last_time_req_time;
// Adjust the remote time based on the round trip time
remote_time += rtt / 2;
// Calculate the offset to our own time
time_offset = remote_time - nowtime;
// Update the time offset
if (client->time_req_seq == 1)
{
// This is the first reply, so this is the only sample we have
// so far
client->time_offset = time_offset;
}
else
{
// Apply a low level filter to the time offset adjustments
client->time_offset = ((client->time_offset * 3) / 4)
+ (time_offset / 4);
}
printf("client %p time offset: %i(%i)->%i\n", client, time_offset, rtt, client->time_offset);
}
// Process a packet received by the server
static void NET_SV_Packet(net_packet_t *packet, net_addr_t *addr)
{
net_client_t *client;
unsigned int packet_type;
// Find which client this packet came from
client = NET_SV_FindClient(addr);
// Read the packet type
if (!NET_ReadInt16(packet, &packet_type))
{
// no packet type
return;
}
if (packet_type == NET_PACKET_TYPE_SYN)
{
NET_SV_ParseSYN(packet, client, addr);
}
else if (client == NULL)
{
// Must come from a valid client; ignore otherwise
}
else if (NET_Conn_Packet(&client->connection, packet, &packet_type))
{
// Packet was eaten by the common connection code
}
else
{
//printf("SV: %s: %i\n", NET_AddrToString(addr), packet_type);
switch (packet_type)
{
case NET_PACKET_TYPE_GAMESTART:
NET_SV_ParseGameStart(packet, client);
break;
case NET_PACKET_TYPE_TIME_RESP:
NET_SV_ParseTimeResponse(packet, client);
break;
default:
// unknown packet type
break;
}
}
// If this address is not in the list of clients, be sure to
// free it back.
if (NET_SV_FindClient(addr) == NULL)
{
NET_FreeAddress(addr);
}
}
static void NET_SV_SendWaitingData(net_client_t *client)
{
net_packet_t *packet;
int num_clients;
int i;
num_clients = NET_SV_NumClients();
// time to send the client another status packet
packet = NET_NewPacket(10);
NET_WriteInt16(packet, NET_PACKET_TYPE_WAITING_DATA);
// include the number of clients waiting
NET_WriteInt8(packet, num_clients);
// indicate whether the client is the controller
NET_WriteInt8(packet, NET_SV_Controller() == client);
// send the index of the client
NET_WriteInt8(packet, NET_SV_ClientIndex(client));
// send the address of all players
for (i=0; i<num_clients; ++i)
{
char *addr;
// name
NET_WriteString(packet, clients[i].name);
// address
addr = NET_AddrToString(clients[i].addr);
NET_WriteString(packet, addr);
}
// send packet to client and free
NET_Conn_SendPacket(&client->connection, packet);
NET_FreePacket(packet);
}
static void NET_SV_SendTimeRequest(net_client_t *client)
{
net_packet_t *packet;
++client->time_req_seq;
// Transmit the request packet
packet = NET_NewPacket(10);
NET_WriteInt16(packet, NET_PACKET_TYPE_TIME_REQ);
NET_WriteInt32(packet, client->time_req_seq);
NET_Conn_SendPacket(&client->connection, packet);
NET_FreePacket(packet);
// Save the time we send the request
client->last_time_req_time = I_GetTimeMS();
}
// Perform any needed action on a client
static void NET_SV_RunClient(net_client_t *client)
{
// Run common code
NET_Conn_Run(&client->connection);
// Is this client disconnected?
if (client->connection.state == NET_CONN_STATE_DISCONNECTED)
{
// deactivate and free back
client->active = false;
free(client->name);
NET_FreeAddress(client->addr);
}
if (!ClientConnected(client))
{
// client has not yet finished connecting
return;
}
if (server_state == SERVER_WAITING_START)
{
// Waiting for the game to start
// Send information once every second
if (client->last_send_time < 0
|| I_GetTimeMS() - client->last_send_time > 1000)
{
NET_SV_SendWaitingData(client);
client->last_send_time = I_GetTimeMS();
}
}
if (client->last_time_req_time < 0)
{
client->last_time_req_time = I_GetTimeMS() - 5000;
}
if (I_GetTimeMS() - client->last_time_req_time > 10000)
{
// Query the clients' times once every ten seconds.
NET_SV_SendTimeRequest(client);
}
}
// Initialise server and wait for connections
void NET_SV_Init(void)
{
int i;
// initialise send/receive context, with loopback send/recv
server_context = NET_NewContext();
NET_AddModule(server_context, &net_loop_server_module);
net_loop_server_module.InitServer();
NET_AddModule(server_context, &net_sdl_module);
net_sdl_module.InitServer();
// no clients yet
for (i=0; i<MAXNETNODES; ++i)
{
clients[i].active = false;
}
server_state = SERVER_WAITING_START;
server_initialised = true;
}
// Run server code to check for new packets/send packets as the server
// requires
void NET_SV_Run(void)
{
net_addr_t *addr;
net_packet_t *packet;
int i;
if (!server_initialised)
{
return;
}
while (NET_RecvPacket(server_context, &addr, &packet))
{
NET_SV_Packet(packet, addr);
}
// "Run" any clients that may have things to do, independent of responses
// to received packets
for (i=0; i<MAXNETNODES; ++i)
{
if (clients[i].active)
{
NET_SV_RunClient(&clients[i]);
}
}
}
void NET_SV_Shutdown(void)
{
int i;
boolean running;
int start_time;
if (!server_initialised)
{
return;
}
fprintf(stderr, "SV: Shutting down server...\n");
// Disconnect all clients
for (i=0; i<MAXNETNODES; ++i)
{
if (clients[i].active)
{
NET_SV_DisconnectClient(&clients[i]);
}
}
// Wait for all clients to finish disconnecting
start_time = I_GetTimeMS();
running = true;
while (running)
{
// Check if any clients are still not finished
running = false;
for (i=0; i<MAXNETNODES; ++i)
{
if (clients[i].active)
{
running = true;
}
}
// Timed out?
if (I_GetTimeMS() - start_time > 5000)
{
running = false;
fprintf(stderr, "SV: Timed out waiting for clients to disconnect.\n");
}
// Run the client code in case this is a loopback client.
NET_CL_Run();
NET_SV_Run();
// Don't hog the CPU
I_Sleep(10);
}
}