ref: 66388c26e971b06a6940620c78d75796f178bcf5
dir: /src/net_query.c/
// Emacs style mode select -*- C++ -*-
//-----------------------------------------------------------------------------
//
// 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.
//
// DESCRIPTION:
// Querying servers to find their current status.
//
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include "i_system.h"
#include "i_timer.h"
#include "net_common.h"
#include "net_defs.h"
#include "net_io.h"
#include "net_packet.h"
#include "net_query.h"
#include "net_structrw.h"
#include "net_sdl.h"
// DNS address of the Internet master server.
#define MASTER_SERVER_ADDRESS "master.chocolate-doom.org:2342"
// Time to wait for a response before declaring a timeout.
#define QUERY_TIMEOUT_SECS 2
// Number of query attempts to make before giving up on a server.
#define QUERY_MAX_ATTEMPTS 3
typedef enum
{
QUERY_TARGET_SERVER, // Normal server target.
QUERY_TARGET_MASTER, // The master server.
QUERY_TARGET_BROADCAST // Send a broadcast query
} query_target_type_t;
typedef enum
{
QUERY_TARGET_QUEUED, // Query not yet sent
QUERY_TARGET_QUERIED, // Query sent, waiting response
QUERY_TARGET_RESPONDED, // Response received
QUERY_TARGET_NO_RESPONSE
} query_target_state_t;
typedef struct
{
query_target_type_t type;
query_target_state_t state;
net_addr_t *addr;
net_querydata_t data;
unsigned int ping_time;
unsigned int query_time;
unsigned int query_attempts;
boolean printed;
} query_target_t;
// Transmit a query packet
static boolean registered_with_master = false;
static net_context_t *query_context;
static query_target_t *targets;
static int num_targets;
static boolean query_loop_running = false;
static boolean printed_header = false;
static int last_query_time = 0;
// Resolve the master server address.
net_addr_t *NET_Query_ResolveMaster(net_context_t *context)
{
net_addr_t *addr;
addr = NET_ResolveAddress(context, MASTER_SERVER_ADDRESS);
if (addr == NULL)
{
fprintf(stderr, "Warning: Failed to resolve address "
"for master server: %s\n", MASTER_SERVER_ADDRESS);
}
return addr;
}
// Send a registration packet to the master server to register
// ourselves with the global list.
void NET_Query_AddToMaster(net_addr_t *master_addr)
{
net_packet_t *packet;
packet = NET_NewPacket(10);
NET_WriteInt16(packet, NET_MASTER_PACKET_TYPE_ADD);
NET_SendPacket(master_addr, packet);
NET_FreePacket(packet);
}
// Process a packet received from the master server.
void NET_Query_MasterResponse(net_packet_t *packet)
{
unsigned int packet_type;
unsigned int result;
if (!NET_ReadInt16(packet, &packet_type)
|| !NET_ReadInt16(packet, &result))
{
return;
}
if (packet_type == NET_MASTER_PACKET_TYPE_ADD_RESPONSE)
{
if (result != 0)
{
// Only show the message once.
if (!registered_with_master)
{
printf("Registered with master server at %s\n",
MASTER_SERVER_ADDRESS);
registered_with_master = true;
}
}
else
{
// Always show rejections.
printf("Failed to register with master server at %s\n",
MASTER_SERVER_ADDRESS);
}
}
}
// Send a query to the master server.
static void NET_Query_SendMasterQuery(net_addr_t *addr)
{
net_packet_t *packet;
packet = NET_NewPacket(10);
NET_WriteInt16(packet, NET_MASTER_PACKET_TYPE_QUERY);
NET_SendPacket(addr, packet);
NET_FreePacket(packet);
}
// Given the specified address, find the target associated. If no
// target is found, and 'create' is true, a new target is created.
static query_target_t *GetTargetForAddr(net_addr_t *addr, boolean create)
{
query_target_t *target;
int i;
for (i=0; i<num_targets; ++i)
{
if (targets[i].addr == addr)
{
return &targets[i];
}
}
if (!create)
{
return NULL;
}
targets = realloc(targets, sizeof(query_target_t) * (num_targets + 1));
target = &targets[num_targets];
target->type = QUERY_TARGET_SERVER;
target->state = QUERY_TARGET_QUEUED;
target->printed = false;
target->query_attempts = 0;
target->addr = addr;
++num_targets;
return target;
}
// Transmit a query packet
static void NET_Query_SendQuery(net_addr_t *addr)
{
net_packet_t *request;
request = NET_NewPacket(10);
NET_WriteInt16(request, NET_PACKET_TYPE_QUERY);
if (addr == NULL)
{
NET_SendBroadcast(query_context, request);
}
else
{
NET_SendPacket(addr, request);
}
NET_FreePacket(request);
}
static void NET_Query_ParseResponse(net_addr_t *addr, net_packet_t *packet,
net_query_callback_t callback,
void *user_data)
{
unsigned int packet_type;
net_querydata_t querydata;
query_target_t *target;
// Read the header
if (!NET_ReadInt16(packet, &packet_type)
|| packet_type != NET_PACKET_TYPE_QUERY_RESPONSE)
{
return;
}
// Read query data
if (!NET_ReadQueryData(packet, &querydata))
{
return;
}
// Find the target that responded.
target = GetTargetForAddr(addr, false);
// If the target is not found, it may be because we are doing
// a LAN broadcast search, in which case we need to create a
// target for the new responder.
if (target == NULL)
{
query_target_t *broadcast_target;
broadcast_target = GetTargetForAddr(NULL, false);
// Not in broadcast mode, unexpected response that came out
// of nowhere. Ignore.
if (broadcast_target == NULL
|| broadcast_target->state != QUERY_TARGET_QUERIED)
{
return;
}
// Create new target.
target = GetTargetForAddr(addr, true);
target->state = QUERY_TARGET_QUERIED;
target->query_time = broadcast_target->query_time;
}
if (target->state != QUERY_TARGET_RESPONDED)
{
target->state = QUERY_TARGET_RESPONDED;
memcpy(&target->data, &querydata, sizeof(net_querydata_t));
// Calculate RTT.
target->ping_time = I_GetTimeMS() - target->query_time;
// Invoke callback to signal that we have a new address.
callback(addr, &target->data, target->ping_time, user_data);
}
}
// Parse a response packet from the master server.
static void NET_Query_ParseMasterResponse(net_addr_t *master_addr,
net_packet_t *packet)
{
unsigned int packet_type;
query_target_t *target;
char *addr_str;
net_addr_t *addr;
// Read the header. We are only interested in query responses.
if (!NET_ReadInt16(packet, &packet_type)
|| packet_type != NET_MASTER_PACKET_TYPE_QUERY_RESPONSE)
{
return;
}
// Read a list of strings containing the addresses of servers
// that the master knows about.
for (;;)
{
addr_str = NET_ReadString(packet);
if (addr_str == NULL)
{
break;
}
// Resolve address and add to targets list if it is not already
// there.
addr = NET_ResolveAddress(query_context, addr_str);
if (addr != NULL)
{
GetTargetForAddr(addr, true);
}
}
// Mark the master as having responded.
target = GetTargetForAddr(master_addr, true);
target->state = QUERY_TARGET_RESPONDED;
}
static void NET_Query_ParsePacket(net_addr_t *addr, net_packet_t *packet,
net_query_callback_t callback,
void *user_data)
{
query_target_t *target;
// This might be the master server responding.
target = GetTargetForAddr(addr, false);
if (target != NULL && target->type == QUERY_TARGET_MASTER)
{
NET_Query_ParseMasterResponse(addr, packet);
}
else
{
NET_Query_ParseResponse(addr, packet, callback, user_data);
}
}
static void NET_Query_GetResponse(net_query_callback_t callback,
void *user_data)
{
net_addr_t *addr;
net_packet_t *packet;
if (NET_RecvPacket(query_context, &addr, &packet))
{
NET_Query_ParsePacket(addr, packet, callback, user_data);
NET_FreePacket(packet);
}
}
// Find a target we have not yet queried and send a query.
static void SendOneQuery(void)
{
unsigned int now;
unsigned int i;
now = I_GetTimeMS();
// Rate limit - only send one query every 50ms.
if (now - last_query_time < 50)
{
return;
}
for (i = 0; i < num_targets; ++i)
{
// Not queried yet?
// Or last query timed out without a response?
if (targets[i].state == QUERY_TARGET_QUEUED
|| (targets[i].state == QUERY_TARGET_QUERIED
&& now - targets[i].query_time > QUERY_TIMEOUT_SECS * 1000))
{
break;
}
}
if (i >= num_targets)
{
return;
}
// Found a target to query. Send a query; how to do this depends on
// the target type.
switch (targets[i].type)
{
case QUERY_TARGET_SERVER:
NET_Query_SendQuery(targets[i].addr);
break;
case QUERY_TARGET_BROADCAST:
NET_Query_SendQuery(NULL);
break;
case QUERY_TARGET_MASTER:
NET_Query_SendMasterQuery(targets[i].addr);
break;
}
//printf("Queried %s\n", NET_AddrToString(targets[i].addr));
targets[i].state = QUERY_TARGET_QUERIED;
targets[i].query_time = now;
++targets[i].query_attempts;
last_query_time = now;
}
// Time out servers that have been queried and not responded.
static void CheckTargetTimeouts(void)
{
unsigned int i;
unsigned int now;
now = I_GetTimeMS();
for (i = 0; i < num_targets; ++i)
{
/*
printf("target %i: state %i, queries %i, query time %i\n",
i, targets[i].state, targets[i].query_attempts,
now - targets[i].query_time);
*/
// We declare a target to be "no response" when we've sent
// multiple query packets to it (QUERY_MAX_ATTEMPTS) and
// received no response to any of them.
if (targets[i].state == QUERY_TARGET_QUERIED
&& targets[i].query_attempts >= QUERY_MAX_ATTEMPTS
&& now - targets[i].query_time > QUERY_TIMEOUT_SECS * 1000)
{
targets[i].state = QUERY_TARGET_NO_RESPONSE;
if (targets[i].type == QUERY_TARGET_MASTER)
{
fprintf(stderr, "NET_MasterQuery: no response "
"from master server.\n");
}
}
}
}
// If all targets have responded or timed out, returns true.
static boolean AllTargetsDone(void)
{
unsigned int i;
for (i = 0; i < num_targets; ++i)
{
if (targets[i].state != QUERY_TARGET_RESPONDED
&& targets[i].state != QUERY_TARGET_NO_RESPONSE)
{
return false;
}
}
return true;
}
// Polling function, invoked periodically to send queries and
// interpret new responses received from remote servers.
// Returns zero when the query sequence has completed and all targets
// have returned responses or timed out.
int NET_Query_Poll(net_query_callback_t callback, void *user_data)
{
CheckTargetTimeouts();
// Send a query. This will only send a single query at once.
SendOneQuery();
// Check for a response
NET_Query_GetResponse(callback, user_data);
return !AllTargetsDone();
}
// Stop the query loop
static void NET_Query_ExitLoop(void)
{
query_loop_running = false;
}
// Loop waiting for responses.
// The specified callback is invoked when a new server responds.
static void NET_Query_QueryLoop(net_query_callback_t callback, void *user_data)
{
query_loop_running = true;
while (query_loop_running && NET_Query_Poll(callback, user_data))
{
// Don't thrash the CPU
I_Sleep(1);
}
}
void NET_Query_Init(void)
{
if (query_context == NULL)
{
query_context = NET_NewContext();
NET_AddModule(query_context, &net_sdl_module);
net_sdl_module.InitClient();
}
free(targets);
targets = NULL;
num_targets = 0;
printed_header = false;
}
// Callback that exits the query loop when the first server is found.
static void NET_Query_ExitCallback(net_addr_t *addr, net_querydata_t *data,
unsigned int ping_time, void *user_data)
{
NET_Query_ExitLoop();
}
// Search the targets list and find a target that has responded.
// If none have responded, returns NULL.
static query_target_t *FindFirstResponder(void)
{
unsigned int i;
for (i = 0; i < num_targets; ++i)
{
if (targets[i].type == QUERY_TARGET_SERVER
&& targets[i].state == QUERY_TARGET_RESPONDED)
{
return &targets[i];
}
}
return NULL;
}
// Return a count of the number of responses.
static int GetNumResponses(void)
{
unsigned int i;
int result;
result = 0;
for (i = 0; i < num_targets; ++i)
{
if (targets[i].type == QUERY_TARGET_SERVER
&& targets[i].state == QUERY_TARGET_RESPONDED)
{
++result;
}
}
return result;
}
int NET_StartLANQuery(void)
{
query_target_t *target;
NET_Query_Init();
// Add a broadcast target to the list.
target = GetTargetForAddr(NULL, true);
target->type = QUERY_TARGET_BROADCAST;
return 1;
}
int NET_StartMasterQuery(void)
{
net_addr_t *master;
query_target_t *target;
NET_Query_Init();
// Resolve master address and add to targets list.
master = NET_Query_ResolveMaster(query_context);
if (master == NULL)
{
return 0;
}
target = GetTargetForAddr(master, true);
target->type = QUERY_TARGET_MASTER;
return 1;
}
// -----------------------------------------------------------------------
static void formatted_printf(int wide, char *s, ...)
{
va_list args;
int i;
va_start(args, s);
i = vprintf(s, args);
va_end(args);
while (i < wide)
{
putchar(' ');
++i;
}
}
static char *GameDescription(GameMode_t mode, GameMission_t mission)
{
switch (mode)
{
case shareware:
return "shareware";
case registered:
return "registered";
case retail:
return "ultimate";
case commercial:
if (mission == doom2)
return "doom2";
else if (mission == pack_tnt)
return "tnt";
else if (mission == pack_plut)
return "plutonia";
default:
return "unknown";
}
}
static void PrintHeader(void)
{
int i;
putchar('\n');
formatted_printf(5, "Ping");
formatted_printf(18, "Address");
formatted_printf(8, "Players");
puts("Description");
for (i=0; i<70; ++i)
putchar('=');
putchar('\n');
}
// Callback function that just prints information in a table.
static void NET_QueryPrintCallback(net_addr_t *addr,
net_querydata_t *data,
unsigned int ping_time,
void *user_data)
{
// If this is the first server, print the header.
if (!printed_header)
{
PrintHeader();
printed_header = true;
}
formatted_printf(5, "%4i", ping_time);
formatted_printf(18, "%s: ", NET_AddrToString(addr));
formatted_printf(8, "%i/%i", data->num_players,
data->max_players);
if (data->gamemode != indetermined)
{
printf("(%s) ", GameDescription(data->gamemode,
data->gamemission));
}
if (data->server_state)
{
printf("(game running) ");
}
NET_SafePuts(data->description);
}
void NET_LANQuery(void)
{
if (NET_StartLANQuery())
{
printf("\nSearching for servers on local LAN ...\n");
NET_Query_QueryLoop(NET_QueryPrintCallback, NULL);
printf("\n%i server(s) found.\n", GetNumResponses());
}
}
void NET_MasterQuery(void)
{
if (NET_StartMasterQuery())
{
printf("\nSearching for servers on Internet ...\n");
NET_Query_QueryLoop(NET_QueryPrintCallback, NULL);
printf("\n%i server(s) found.\n", GetNumResponses());
}
}
void NET_QueryAddress(char *addr_str)
{
net_addr_t *addr;
query_target_t *target;
NET_Query_Init();
addr = NET_ResolveAddress(query_context, addr_str);
if (addr == NULL)
{
I_Error("NET_QueryAddress: Host '%s' not found!", addr_str);
}
// Add the address to the list of targets.
target = GetTargetForAddr(addr, true);
printf("\nQuerying '%s'...\n", addr_str);
// Run query loop.
NET_Query_QueryLoop(NET_Query_ExitCallback, NULL);
// Check if the target responded.
if (target->state == QUERY_TARGET_RESPONDED)
{
NET_QueryPrintCallback(addr, &target->data, target->ping_time, NULL);
}
else
{
I_Error("No response from '%s'", addr_str);
}
}
net_addr_t *NET_FindLANServer(void)
{
query_target_t *target;
query_target_t *responder;
NET_Query_Init();
// Add a broadcast target to the list.
target = GetTargetForAddr(NULL, true);
target->type = QUERY_TARGET_BROADCAST;
// Run the query loop, and stop at the first target found.
NET_Query_QueryLoop(NET_Query_ExitCallback, NULL);
responder = FindFirstResponder();
if (responder != NULL)
{
return responder->addr;
}
else
{
return NULL;
}
}