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/* $Id$ */

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/**

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 * @file core/udp.cpp Basic functions to receive and send UDP packets.

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 */

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#ifdef ENABLE_NETWORK

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#include "../../stdafx.h"

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#include "../../debug.h"

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#include "../../core/bitmath_func.hpp"

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#include "../../core/math_func.hpp"

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#include "packet.h"

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#include "udp.h"

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/**

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 * Start listening on the given host and port.

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 * @param host      the host (ip) to listen on

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 * @param port      the port to listen on

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 * @param broadcast whether to allow broadcast sending/receiving

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 * @return true if the listening succeeded

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 */

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bool NetworkUDPSocketHandler::Listen(const uint32 host, const uint16 port, const bool broadcast)

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{

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	struct sockaddr_in sin;

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	/* Make sure socket is closed */

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	this->Close();

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	this->sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);

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	if (!this->IsConnected()) {

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		DEBUG(net, 0, "[udp] failed to start UDP listener");

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		return false;

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	}

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	SetNonBlocking(this->sock);

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	sin.sin_family = AF_INET;

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	/* Listen on all IPs */

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	sin.sin_addr.s_addr = host;

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	sin.sin_port = htons(port);

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	if (bind(this->sock, (struct sockaddr*)&sin, sizeof(sin)) != 0) {

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		DEBUG(net, 0, "[udp] bind failed on %s:%i", inet_ntoa(*(struct in_addr *)&host), port);

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		return false;

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	}

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	if (broadcast) {

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		/* Enable broadcast */

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		unsigned long val = 1;

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#ifndef BEOS_NET_SERVER // will work around this, some day; maybe.

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		setsockopt(this->sock, SOL_SOCKET, SO_BROADCAST, (char *) &val , sizeof(val));

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#endif

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	}

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	DEBUG(net, 1, "[udp] listening on port %s:%d", inet_ntoa(*(struct in_addr *)&host), port);

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	return true;

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}

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/**

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 * Close the given UDP socket

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 */

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void NetworkUDPSocketHandler::Close()

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{

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	if (!this->IsConnected()) return;

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	closesocket(this->sock);

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	this->sock = INVALID_SOCKET;

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}

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NetworkRecvStatus NetworkUDPSocketHandler::CloseConnection()

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{

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	this->has_quit = true;

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	return NETWORK_RECV_STATUS_OKAY;

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}

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/**

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 * Send a packet over UDP

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 * @param p    the packet to send

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 * @param recv the receiver (target) of the packet

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 */

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void NetworkUDPSocketHandler::SendPacket(Packet *p, const struct sockaddr_in *recv)

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{

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	int res;

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	p->PrepareToSend();

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	/* Send the buffer */

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	res = sendto(this->sock, (const char*)p->buffer, p->size, 0, (struct sockaddr *)recv, sizeof(*recv));

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	/* Check for any errors, but ignore it otherwise */

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	if (res == -1) DEBUG(net, 1, "[udp] sendto failed with: %i", GET_LAST_ERROR());

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}

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/**

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 * Receive a packet at UDP level

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 */

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void NetworkUDPSocketHandler::ReceivePackets()

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{

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	struct sockaddr_in client_addr;

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	socklen_t client_len;

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	int nbytes;

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	Packet p(this);

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	int packet_len;

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	if (!this->IsConnected()) return;

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	packet_len = sizeof(p.buffer);

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	client_len = sizeof(client_addr);

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	/* Try to receive anything */

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	SetNonBlocking(this->sock); // Some OSes seem to loose the non-blocking status of the socket

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	nbytes = recvfrom(this->sock, (char*)p.buffer, packet_len, 0, (struct sockaddr *)&client_addr, &client_len);

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	/* We got some bytes for the base header of the packet. */

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	if (nbytes > 2) {

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		p.PrepareToRead();

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		/* If the size does not match the packet must be corrupted.

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		 * Otherwise it will be marked as corrupted later on. */

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		if (nbytes != p.size) {

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			DEBUG(net, 1, "received a packet with mismatching size from %s:%d",

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					inet_ntoa(client_addr.sin_addr), ntohs(client_addr.sin_port));

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			return;

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		}

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		/* Handle the packet */

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		this->HandleUDPPacket(&p, &client_addr);

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	}

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}

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/**

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 * Serializes the NetworkGameInfo struct to the packet

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 * @param p    the packet to write the data to

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 * @param info the NetworkGameInfo struct to serialize

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 */

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void NetworkUDPSocketHandler::Send_NetworkGameInfo(Packet *p, const NetworkGameInfo *info)

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{

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	p->Send_uint8 (NETWORK_GAME_INFO_VERSION);

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	/*

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	 *              Please observe the order.

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	 * The parts must be read in the same order as they are sent!

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	 */

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	/* Update the documentation in udp.h on changes

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	 * to the NetworkGameInfo wire-protocol! */

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	/* NETWORK_GAME_INFO_VERSION = 4 */

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	{

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		/* Only send the GRF Identification (GRF_ID and MD5 checksum) of

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		 * the GRFs that are needed, i.e. the ones that the server has

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		 * selected in the NewGRF GUI and not the ones that are used due

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		 * to the fact that they are in [newgrf-static] in openttd.cfg */

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		const GRFConfig *c;

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		uint count = 0;

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		/* Count number of GRFs to send information about */

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		for (c = info->grfconfig; c != NULL; c = c->next) {

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			if (!HasBit(c->flags, GCF_STATIC)) count++;

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		}

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		p->Send_uint8 (count); // Send number of GRFs

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		/* Send actual GRF Identifications */

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		for (c = info->grfconfig; c != NULL; c = c->next) {

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			if (!HasBit(c->flags, GCF_STATIC)) this->Send_GRFIdentifier(p, c);

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		}

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	}

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	/* NETWORK_GAME_INFO_VERSION = 3 */

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	p->Send_uint32(info->game_date);

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	p->Send_uint32(info->start_date);

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	/* NETWORK_GAME_INFO_VERSION = 2 */

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	p->Send_uint8 (info->companies_max);

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	p->Send_uint8 (info->companies_on);

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	p->Send_uint8 (info->spectators_max);

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	/* NETWORK_GAME_INFO_VERSION = 1 */

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	p->Send_string(info->server_name);

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	p->Send_string(info->server_revision);

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	p->Send_uint8 (info->server_lang);

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	p->Send_bool  (info->use_password);

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	p->Send_uint8 (info->clients_max);

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	p->Send_uint8 (info->clients_on);

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	p->Send_uint8 (info->spectators_on);

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	p->Send_string(info->map_name);

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	p->Send_uint16(info->map_width);

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	p->Send_uint16(info->map_height);

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	p->Send_uint8 (info->map_set);

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	p->Send_bool  (info->dedicated);

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}

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/**

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 * Deserializes the NetworkGameInfo struct from the packet

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 * @param p    the packet to read the data from

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 * @param info the NetworkGameInfo to deserialize into

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 */

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void NetworkUDPSocketHandler::Recv_NetworkGameInfo(Packet *p, NetworkGameInfo *info)

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{

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	static const Date MAX_DATE = ConvertYMDToDate(MAX_YEAR, 11, 31); // December is month 11

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	info->game_info_version = p->Recv_uint8();

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	/*

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	 *              Please observe the order.

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	 * The parts must be read in the same order as they are sent!

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	 */

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	/* Update the documentation in udp.h on changes

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	 * to the NetworkGameInfo wire-protocol! */

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	switch (info->game_info_version) {

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		case 4: {

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			GRFConfig **dst = &info->grfconfig;

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			uint i;

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			uint num_grfs = p->Recv_uint8();

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			for (i = 0; i < num_grfs; i++) {

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				GRFConfig *c = CallocT<GRFConfig>(1);

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				this->Recv_GRFIdentifier(p, c);

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				this->HandleIncomingNetworkGameInfoGRFConfig(c);

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				/* Append GRFConfig to the list */

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				*dst = c;

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				dst = &c->next;

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			}

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		} /* Fallthrough */

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		case 3:

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			info->game_date      = Clamp(p->Recv_uint32(), 0, MAX_DATE);

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			info->start_date     = Clamp(p->Recv_uint32(), 0, MAX_DATE);

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			/* Fallthrough */

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		case 2:

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			info->companies_max  = p->Recv_uint8 ();

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			info->companies_on   = p->Recv_uint8 ();

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			info->spectators_max = p->Recv_uint8 ();

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			/* Fallthrough */

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		case 1:

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			p->Recv_string(info->server_name,     sizeof(info->server_name));

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			p->Recv_string(info->server_revision, sizeof(info->server_revision));

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			info->server_lang    = p->Recv_uint8 ();

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			info->use_password   = p->Recv_bool  ();

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			info->clients_max    = p->Recv_uint8 ();

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			info->clients_on     = p->Recv_uint8 ();

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			info->spectators_on  = p->Recv_uint8 ();

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			if (info->game_info_version < 3) { // 16 bits dates got scrapped and are read earlier

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				info->game_date    = p->Recv_uint16() + DAYS_TILL_ORIGINAL_BASE_YEAR;

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				info->start_date   = p->Recv_uint16() + DAYS_TILL_ORIGINAL_BASE_YEAR;

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			}

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			p->Recv_string(info->map_name, sizeof(info->map_name));

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			info->map_width      = p->Recv_uint16();

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			info->map_height     = p->Recv_uint16();

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			info->map_set        = p->Recv_uint8 ();

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			info->dedicated      = p->Recv_bool  ();

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			if (info->server_lang >= NETWORK_NUM_LANGUAGES)  info->server_lang = 0;

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			if (info->map_set     >= NETWORK_NUM_LANDSCAPES) info->map_set     = 0;

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	}

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}

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/**

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 * Defines a simple (switch) case for each network packet

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 * @param type the packet type to create the case for

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 */

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#define UDP_COMMAND(type) case type: this->NetworkPacketReceive_ ## type ## _command(p, client_addr); break;

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/**

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 * Handle an incoming packets by sending it to the correct function.

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 * @param p the received packet

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 * @param client_addr the sender of the packet

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 */

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void NetworkUDPSocketHandler::HandleUDPPacket(Packet *p, const struct sockaddr_in *client_addr)

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{

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	PacketUDPType type;

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	/* New packet == new client, which has not quit yet */

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	this->has_quit = false;

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	type = (PacketUDPType)p->Recv_uint8();

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	switch (this->HasClientQuit() ? PACKET_UDP_END : type) {

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		UDP_COMMAND(PACKET_UDP_CLIENT_FIND_SERVER);

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		UDP_COMMAND(PACKET_UDP_SERVER_RESPONSE);

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		UDP_COMMAND(PACKET_UDP_CLIENT_DETAIL_INFO);

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		UDP_COMMAND(PACKET_UDP_SERVER_DETAIL_INFO);

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		UDP_COMMAND(PACKET_UDP_SERVER_REGISTER);

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		UDP_COMMAND(PACKET_UDP_MASTER_ACK_REGISTER);

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		UDP_COMMAND(PACKET_UDP_CLIENT_GET_LIST);

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		UDP_COMMAND(PACKET_UDP_MASTER_RESPONSE_LIST);

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		UDP_COMMAND(PACKET_UDP_SERVER_UNREGISTER);

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		UDP_COMMAND(PACKET_UDP_CLIENT_GET_NEWGRFS);

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		UDP_COMMAND(PACKET_UDP_SERVER_NEWGRFS);

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		default:

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			if (this->HasClientQuit()) {

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				DEBUG(net, 0, "[udp] received invalid packet type %d from %s:%d", type,  inet_ntoa(client_addr->sin_addr), ntohs(client_addr->sin_port));

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			} else {

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				DEBUG(net, 0, "[udp] received illegal packet from %s:%d", inet_ntoa(client_addr->sin_addr), ntohs(client_addr->sin_port));

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			}

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			break;

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	}

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}

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/**

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 * Create stub implementations for all receive commands that only

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 * show a warning that the given command is not available for the

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 * socket where the packet came from.

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 * @param type the packet type to create the stub for

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 */

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#define DEFINE_UNAVAILABLE_UDP_RECEIVE_COMMAND(type) \

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void NetworkUDPSocketHandler::NetworkPacketReceive_## type ##_command(\

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		Packet *p, const struct sockaddr_in *client_addr) { \

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	DEBUG(net, 0, "[udp] received packet type %d on wrong port from %s:%d", \

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			type, inet_ntoa(client_addr->sin_addr), ntohs(client_addr->sin_port)); \

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}

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DEFINE_UNAVAILABLE_UDP_RECEIVE_COMMAND(PACKET_UDP_CLIENT_FIND_SERVER);

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DEFINE_UNAVAILABLE_UDP_RECEIVE_COMMAND(PACKET_UDP_SERVER_RESPONSE);

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DEFINE_UNAVAILABLE_UDP_RECEIVE_COMMAND(PACKET_UDP_CLIENT_DETAIL_INFO);

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DEFINE_UNAVAILABLE_UDP_RECEIVE_COMMAND(PACKET_UDP_SERVER_DETAIL_INFO);

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DEFINE_UNAVAILABLE_UDP_RECEIVE_COMMAND(PACKET_UDP_SERVER_REGISTER);

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DEFINE_UNAVAILABLE_UDP_RECEIVE_COMMAND(PACKET_UDP_MASTER_ACK_REGISTER);

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DEFINE_UNAVAILABLE_UDP_RECEIVE_COMMAND(PACKET_UDP_CLIENT_GET_LIST);

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DEFINE_UNAVAILABLE_UDP_RECEIVE_COMMAND(PACKET_UDP_MASTER_RESPONSE_LIST);

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DEFINE_UNAVAILABLE_UDP_RECEIVE_COMMAND(PACKET_UDP_SERVER_UNREGISTER);

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DEFINE_UNAVAILABLE_UDP_RECEIVE_COMMAND(PACKET_UDP_CLIENT_GET_NEWGRFS);

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DEFINE_UNAVAILABLE_UDP_RECEIVE_COMMAND(PACKET_UDP_SERVER_NEWGRFS);

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#endif /* ENABLE_NETWORK */