sm-ext-A2SFixes/extension.cpp

/**
 * vim: set ts=4 :
 * =============================================================================
 * SourceMod A2SFixes Extension
 * Copyright (C) 2004-2008 AlliedModders LLC.  All rights reserved.
 * =============================================================================
 *
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License, version 3.0, as published by the
 * Free Software Foundation.
 *
 * 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, see <http://www.gnu.org/licenses/>.
 *
 * As a special exception, AlliedModders LLC gives you permission to link the
 * code of this program (as well as its derivative works) to "Half-Life 2," the
 * "Source Engine," the "SourcePawn JIT," and any Game MODs that run on software
 * by the Valve Corporation.  You must obey the GNU General Public License in
 * all respects for all other code used.  Additionally, AlliedModders LLC grants
 * this exception to all derivative works.  AlliedModders LLC defines further
 * exceptions, found in LICENSE.txt (as of this writing, version JULY-31-2007),
 * or <http://www.sourcemod.net/license.php>.
 *
 * Version: $Id$
 */

#include "extension.h"
#include "string.h"
#include "sys/socket.h"
#include "iplayerinfo.h"
#include <inetchannel.h>
#include "CDetour/detours.h"
#include <bitbuf.h>

#define DETOUR_CREATE_MEMBER_ADDRESS(name, address) CDetourManager::CreateDetour(GET_MEMBER_CALLBACK(name), GET_MEMBER_TRAMPOLINE(name), address);
#define DETOUR_CREATE_STATIC_ADDRESS(name, address) CDetourManager::CreateDetour(GET_STATIC_CALLBACK(name), GET_STATIC_TRAMPOLINE(name), address);

#define A2S_INFO_REQUEST    "\xFF\xFF\xFF\xFF\x54"
#define A2S_INFO_REPLY      "\xFF\xFF\xFF\xFF\x49"

#define A2S_PLAYER_REQUEST  "\xFF\xFF\xFF\xFF\x55"
#define A2S_PLAYER_REPLY    "\xFF\xFF\xFF\xFF\x44"

/**
 * @file extension.cpp
 * @brief Implement extension code here.
 */

A2SFixes g_Interface;
SMEXT_LINK(&g_Interface);

CDetour *g_pDetour_SendTo = NULL;

ConVar g_A2SMaxPlayers("a2s_maxplayers", "-1", FCVAR_NONE, "Maximum Players in the A2S Packet.");
ConVar g_A2SIncludeSourceTV("a2s_includesourcetv", "0", FCVAR_NONE, "Include SourceTV in the Player Count and List.");

char *NewBuf;
char *OldBuf;

int g_iFakePlayers = 0;

struct PlayerInfo
{
	char Name[32];
	long Score;
	float Time;
};

/**
 * @brief
 */
DETOUR_DECL_STATIC6(Detour_SendTo, int, int, s, char *, buf, int, len, int, flags, sockaddr *, to, socklen_t*, tolen)
{
	if (memcmp(buf, A2S_INFO_REPLY, 5) == 0)
	{
		delete[] NewBuf;
		NewBuf = new char[len];

		// Copy memory
		memcpy(NewBuf, buf, len);

		// Store Pointer
		OldBuf = NewBuf;

		// Skip header and protocol
		NewBuf += 5;

		// Skip server name
		while(*NewBuf)
			NewBuf++;

		NewBuf++;

		// Skip map name
		while(*NewBuf)
			NewBuf++;

		NewBuf++;

		// Skip folder
		while(*NewBuf)
			NewBuf++;

		NewBuf++;

		// Skip game name
		while(*NewBuf)
			NewBuf++;

		NewBuf++;

		// Skip game id
		NewBuf += 2;

		// Calculate playercount
		int iPlayers = 0;

		for (int index = 0; index <= SM_MAXPLAYERS; index++)
		{
			IGamePlayer *pPlayer = playerhelpers->GetGamePlayer(index);

			if (pPlayer != NULL && pPlayer->IsConnected() && (!pPlayer->IsSourceTV() || g_A2SIncludeSourceTV.GetInt()))
			{
				iPlayers++;
			}
		}

		iPlayers += g_iFakePlayers;

		// Correct playercount
		memset(NewBuf, iPlayers, 1);

		// Set MaxPlayers
		int iMaxPlayers = g_A2SMaxPlayers.GetInt();
		if (iMaxPlayers > 0)
		{
			NewBuf++;
			memset(NewBuf, iMaxPlayers, 1);
		}

		// Reset Pointer
		NewBuf = OldBuf;

		return DETOUR_STATIC_CALL(Detour_SendTo)(s, NewBuf, len, flags, to, tolen);
	}

	if (memcmp(buf, A2S_PLAYER_REPLY, 5) == 0)
	{
		int iPlayers = 0;

		PlayerInfo PlayerList[SM_MAXPLAYERS];

		for (int index = 0; index <= SM_MAXPLAYERS; index++)
		{
			IGamePlayer *pPlayer = playerhelpers->GetGamePlayer(index);

			if (pPlayer != NULL && pPlayer->IsConnected() && pPlayer->IsInGame() && (!pPlayer->IsSourceTV() || g_A2SIncludeSourceTV.GetInt()))
			{
				memcpy(PlayerList[iPlayers].Name, pPlayer->GetName(), 32);

				IPlayerInfo *pInfo = pPlayer->GetPlayerInfo();

				if (pInfo != NULL)
					PlayerList[iPlayers].Score = pInfo->GetFragCount();
				else
					PlayerList[iPlayers].Score = 0;

				INetChannelInfo *pNetInfo = engine->GetPlayerNetInfo(index);

				if (pNetInfo != NULL)
					PlayerList[iPlayers].Time = pNetInfo->GetTimeConnected();
				else
					PlayerList[iPlayers].Time = 0.0;

				iPlayers++;
			}
		}

		char PlayerReply[1024 * 6];
		bf_write PlayerReplyPacket(PlayerReply, sizeof(PlayerReply));

		PlayerReplyPacket.Reset(); // Build up the packet as a bitbuffer so we can use the nice helper functions to do the work for us

		PlayerReplyPacket.WriteLong(-1); // FF FF FF FF
		PlayerReplyPacket.WriteByte(68); // 44

		PlayerReplyPacket.WriteByte(iPlayers); // Number of players

		for (int index = 0; index < iPlayers; index++)
		{
			PlayerReplyPacket.WriteByte(index);
			PlayerReplyPacket.WriteString(PlayerList[index].Name);
			PlayerReplyPacket.WriteLong(PlayerList[index].Score);
			PlayerReplyPacket.WriteFloat(PlayerList[index].Time);
		}

		return DETOUR_STATIC_CALL(Detour_SendTo)(s, (char *)PlayerReplyPacket.GetData(), PlayerReplyPacket.GetNumBytesWritten(), flags, to, tolen);
	}

	return DETOUR_STATIC_CALL(Detour_SendTo)(s, buf, len, flags, to, tolen);
}

/**
 * @brief
 */
cell_t SetFakePlayerCount(IPluginContext *pContext, const cell_t *params)
{
	g_iFakePlayers = params[1];
	return 1;
}

/**
 * @brief
 */
const sp_nativeinfo_t g_ExtensionNatives[] =
{
	{"A2S_SetFakePlayerCount",  SetFakePlayerCount},
	{NULL,                      NULL},
};

/**
 * @brief This is called after the initial loading sequence has been processed.
 *
 * @param error		Error message buffer.
 * @param maxlength	Size of error message buffer.
 * @param late		Whether or not the module was loaded after map load.
 * @return			True to succeed loading, false to fail.
 */
bool A2SFixes::SDK_OnLoad(char *error, size_t maxlength, bool late)
{
	CDetourManager::Init(g_pSM->GetScriptingEngine(), NULL);

	g_pDetour_SendTo = DETOUR_CREATE_STATIC_ADDRESS(Detour_SendTo, (void*)sendto);

	if (g_pDetour_SendTo == NULL)
	{
		snprintf(error, maxlength, "Could not create detour for 'sendto'");
		SDK_OnUnload();
		return false;
	}

	g_pDetour_SendTo->EnableDetour();
	return true;
}

/**
 * @brief This is called right before the extension is unloaded.
 */
void A2SFixes::SDK_OnUnload()
{
	if (g_pDetour_SendTo != NULL)
	{
		g_pDetour_SendTo->Destroy();
		g_pDetour_SendTo = NULL;
	}
}

/**
 * @brief This is called once all known extensions have been loaded.
 * Note: It is is a good idea to add natives here, if any are provided.
 */
void A2SFixes::SDK_OnAllLoaded()
{
	sharesys->AddNatives(myself, g_ExtensionNatives);
	sharesys->RegisterLibrary(myself, "A2SFixes");
}

/**
 * @brief Called when Metamod is attached, before the extension version is called.
 *
 * @param error			Error buffer.
 * @param maxlength		Maximum size of error buffer.
 * @param late			Whether or not Metamod considers this a late load.
 * @return				True to succeed, false to fail.
 */
bool A2SFixes::SDK_OnMetamodLoad(ISmmAPI *ismm, char *error, size_t maxlen, bool late)
{
	GET_V_IFACE_CURRENT(GetEngineFactory, engine, IVEngineServer, INTERFACEVERSION_VENGINESERVER);
	GET_V_IFACE_CURRENT(GetEngineFactory, g_pCVar, ICvar, CVAR_INTERFACE_VERSION);
	ConVar_Register(0, this);

	return true;
}

/**
 * @brief
 */
bool A2SFixes::RegisterConCommandBase(ConCommandBase *pVar)
{
	/* Always call META_REGCVAR instead of going through the engine. */
	return META_REGCVAR(pVar);
}