Allow 256 NewGRFs in multiplayer

Add extended network format for server info Add general UDP packet fragmentation system Fix map dimensions >= 64k Increase length of server revision string Maintain backwards compatibility with trunk for advertisement/server listing
2018-05-12 09:11:41 +01:00
parent 9b42ae954c
commit 6342099c4d
16 changed files with 382 additions and 78 deletions
--- a/src/network/core/config.h
+++ b/src/network/core/config.h
@@ -44,6 +44,7 @@ static const uint NETWORK_COMPANY_NAME_LENGTH     =  128;         ///< The maxim
 static const uint NETWORK_HOSTNAME_LENGTH         =   80;         ///< The maximum length of the host name, in bytes including '\0'
 static const uint NETWORK_SERVER_ID_LENGTH        =   33;         ///< The maximum length of the network id of the servers, in bytes including '\0'
 static const uint NETWORK_REVISION_LENGTH         =   15;         ///< The maximum length of the revision, in bytes including '\0'
+static const uint NETWORK_LONG_REVISION_LENGTH    =   64;         ///< The maximum length of the revision, in bytes including '\0'
 static const uint NETWORK_PASSWORD_LENGTH         =   33;         ///< The maximum length of the password, in bytes including '\0' (must be >= NETWORK_SERVER_ID_LENGTH)
 static const uint NETWORK_CLIENTS_LENGTH          =  200;         ///< The maximum length for the list of clients that controls a company, in bytes including '\0'
 static const uint NETWORK_CLIENT_NAME_LENGTH      =   25;         ///< The maximum length of a client's name, in bytes including '\0'
--- a/src/network/core/game.h
+++ b/src/network/core/game.h
@@ -37,11 +37,12 @@ struct NetworkGameInfo : NetworkServerGameInfo {
 	GRFConfig *grfconfig;                           ///< List of NewGRF files used
 	Date start_date;                                ///< When the game started
 	Date game_date;                                 ///< Current date
-	uint16 map_width;                               ///< Map width
-	uint16 map_height;                              ///< Map height
+	uint32 map_width;                               ///< Map width
+	uint32 map_height;                              ///< Map height
 	char server_name[NETWORK_NAME_LENGTH];          ///< Server name
 	char hostname[NETWORK_HOSTNAME_LENGTH];         ///< Hostname of the server (if any)
-	char server_revision[NETWORK_REVISION_LENGTH];  ///< The version number the server is using (e.g.: 'r304' or 0.5.0)
+	char short_server_revision[NETWORK_REVISION_LENGTH]; ///< The version number the server is using (e.g.: 'r304' or 0.5.0) (truncated)
+	char server_revision[NETWORK_LONG_REVISION_LENGTH];  ///< The version number the server is using (e.g.: 'r304' or 0.5.0)
 	bool dedicated;                                 ///< Is this a dedicated server?
 	bool version_compatible;                        ///< Can we connect to this server or not? (based on server_revision)
 	bool compatible;                                ///< Can we connect to this server or not? (based on server_revision _and_ grf_match
--- a/src/network/core/packet.cpp
+++ b/src/network/core/packet.cpp
@@ -42,14 +42,8 @@ Packet::Packet(NetworkSocketHandler *cs)
 */
 Packet::Packet(PacketType type)
 {
-	this->cs                   = NULL;
-	this->next                 = NULL;
-
-	/* Skip the size so we can write that in before sending the packet */
-	this->pos                  = 0;
-	this->size                 = sizeof(PacketSize);
 	this->buffer = MallocT<byte>(SHRT_MAX);
-	this->buffer[this->size++] = type;
+	this->ResetState(type);
 }

 /**
@@ -60,6 +54,17 @@ Packet::~Packet()
 	free(this->buffer);
 }

+void Packet::ResetState(PacketType type)
+{
+	this->cs                   = NULL;
+	this->next                 = NULL;
+
+	/* Skip the size so we can write that in before sending the packet */
+	this->pos                  = 0;
+	this->size                 = sizeof(PacketSize);
+	this->buffer[this->size++] = type;
+}
+
 /**
 * Writes the packet size from the raw packet from packet->size
 */
@@ -181,16 +186,17 @@ void Packet::Send_binary(const char *data, const size_t size)
 /**
 * Is it safe to read from the packet, i.e. didn't we run over the buffer ?
 * @param bytes_to_read The amount of bytes we want to try to read.
+ * @param non_fatal True if a false return value is considered non-fatal, and will not raise an error.
 * @return True if that is safe, otherwise false.
 */
-bool Packet::CanReadFromPacket(uint bytes_to_read)
+bool Packet::CanReadFromPacket(uint bytes_to_read, bool non_fatal)
 {
 	/* Don't allow reading from a quit client/client who send bad data */
 	if (this->cs->HasClientQuit()) return false;

 	/* Check if variable is within packet-size */
 	if (this->pos + bytes_to_read > this->size) {
-		this->cs->NetworkSocketHandler::CloseConnection();
+		if (!non_fatal) this->cs->NetworkSocketHandler::CloseConnection();
 		return false;
 	}

--- a/src/network/core/packet.h
+++ b/src/network/core/packet.h
@@ -64,6 +64,8 @@ public:
 	Packet(PacketType type);
 	~Packet();

+	void ResetState(PacketType type);
+
 	/* Sending/writing of packets */
 	void PrepareToSend();

@@ -79,7 +81,7 @@ public:
 	void ReadRawPacketSize();
 	void PrepareToRead();

-	bool   CanReadFromPacket (uint bytes_to_read);
+	bool   CanReadFromPacket (uint bytes_to_read, bool non_fatal = false);
 	bool   Recv_bool  ();
 	uint8  Recv_uint8 ();
 	uint16 Recv_uint16();
--- a/src/network/core/tcp.cpp
+++ b/src/network/core/tcp.cpp
@@ -184,11 +184,6 @@ Packet *NetworkTCPSocketHandler::ReceivePacket()

 		/* Read the packet size from the received packet */
 		p->ReadRawPacketSize();
-
-		if (p->size > SEND_MTU) {
-			this->CloseConnection();
-			return NULL;
-		}
 	}

 	/* Read rest of packet */
--- a/src/network/core/udp.cpp
+++ b/src/network/core/udp.cpp
@@ -16,10 +16,14 @@
 #include "../../stdafx.h"
 #include "../../date_func.h"
 #include "../../debug.h"
+#include "../../core/random_func.hpp"
+#include "../../fios.h"
 #include "udp.h"

 #include "../../safeguards.h"

+extern const uint8 _out_of_band_grf_md5[16];
+
 /**
 * Create an UDP socket but don't listen yet.
 * @param bind the addresses to bind to.
@@ -37,6 +41,8 @@ NetworkUDPSocketHandler::NetworkUDPSocketHandler(NetworkAddressList *bind)
 		*this->bind.Append() = NetworkAddress(NULL, 0, AF_INET);
 		*this->bind.Append() = NetworkAddress(NULL, 0, AF_INET6);
 	}
+
+	this->fragment_token = ((uint64) InteractiveRandom()) | (((uint64) InteractiveRandom()) << 32);
 }


@@ -84,6 +90,33 @@ void NetworkUDPSocketHandler::SendPacket(Packet *p, NetworkAddress *recv, bool a
 {
 	if (this->sockets.Length() == 0) this->Listen();

+	if (p->size > SEND_MTU) {
+		p->PrepareToSend();
+
+		uint64 token = this->fragment_token++;
+		const uint PAYLOAD_MTU = SEND_MTU - (1 + 2 + 8 + 1 + 1 + 2);
+
+		const uint8 frag_count = (p->size + PAYLOAD_MTU - 1) / PAYLOAD_MTU;
+
+		Packet frag(PACKET_UDP_EX_MULTI);
+		uint8 current_frag = 0;
+		uint16 offset = 0;
+		while (offset < p->size) {
+			uint16 payload_size = min<uint>(PAYLOAD_MTU, p->size - offset);
+			frag.Send_uint64(token);
+			frag.Send_uint8 (current_frag);
+			frag.Send_uint8 (frag_count);
+			frag.Send_uint16 (payload_size);
+			frag.Send_binary((const char *) p->buffer + offset, payload_size);
+			current_frag++;
+			offset += payload_size;
+			this->SendPacket(&frag, recv, all, broadcast);
+			frag.ResetState(PACKET_UDP_EX_MULTI);
+		}
+		assert_msg(current_frag == frag_count, "%u, %u", current_frag, frag_count);
+		return;
+	}
+
 	for (SocketList::iterator s = this->sockets.Begin(); s != this->sockets.End(); s++) {
 		/* Make a local copy because if we resolve it we cannot
 		 * easily unresolve it so we can resolve it later again. */
@@ -142,7 +175,7 @@ void NetworkUDPSocketHandler::ReceivePackets()
 			/* If the size does not match the packet must be corrupted.
 			 * Otherwise it will be marked as corrupted later on. */
 			if (nbytes != p.size) {
-				DEBUG(net, 1, "received a packet with mismatching size from %s", address.GetAddressAsString());
+				DEBUG(net, 1, "received a packet with mismatching size from %s, (%u, %u)", address.GetAddressAsString(), nbytes, p.size);
 				continue;
 			}

@@ -183,11 +216,24 @@ void NetworkUDPSocketHandler::SendNetworkGameInfo(Packet *p, const NetworkGameIn
 		for (c = info->grfconfig; c != NULL; c = c->next) {
 			if (!HasBit(c->flags, GCF_STATIC)) count++;
 		}
-		p->Send_uint8 (count); // Send number of GRFs
+		p->Send_uint8(min<uint>(count, NETWORK_MAX_GRF_COUNT)); // Send number of GRFs

 		/* Send actual GRF Identifications */
+		uint index = 0;
 		for (c = info->grfconfig; c != NULL; c = c->next) {
-			if (!HasBit(c->flags, GCF_STATIC)) this->SendGRFIdentifier(p, &c->ident);
+			if (!HasBit(c->flags, GCF_STATIC)) {
+				if (index == NETWORK_MAX_GRF_COUNT - 1 && count > NETWORK_MAX_GRF_COUNT) {
+					/* Send fake GRF ID */
+
+					p->Send_uint32(0x56D2B000);
+					p->Send_binary((const char*) _out_of_band_grf_md5, 16);
+				} else if (index >= NETWORK_MAX_GRF_COUNT) {
+					break;
+				} else {
+					this->SendGRFIdentifier(p, &c->ident);
+				}
+				index++;
+			}
 		}
 	}

@@ -202,7 +248,7 @@ void NetworkUDPSocketHandler::SendNetworkGameInfo(Packet *p, const NetworkGameIn

 	/* NETWORK_GAME_INFO_VERSION = 1 */
 	p->Send_string(info->server_name);
-	p->Send_string(info->server_revision);
+	p->Send_string(info->short_server_revision);
 	p->Send_uint8 (info->server_lang);
 	p->Send_bool  (info->use_password);
 	p->Send_uint8 (info->clients_max);
@@ -215,6 +261,56 @@ void NetworkUDPSocketHandler::SendNetworkGameInfo(Packet *p, const NetworkGameIn
 	p->Send_bool  (info->dedicated);
 }

+/**
+ * Serializes the NetworkGameInfo struct to the packet
+ * @param p    the packet to write the data to
+ * @param info the NetworkGameInfo struct to serialize
+ */
+void NetworkUDPSocketHandler::SendNetworkGameInfoExtended(Packet *p, const NetworkGameInfo *info, uint16 version)
+{
+	p->Send_uint8(0); // version num
+
+	p->Send_uint32(info->game_date);
+	p->Send_uint32(info->start_date);
+	p->Send_uint8 (info->companies_max);
+	p->Send_uint8 (info->companies_on);
+	p->Send_uint8 (info->spectators_max);
+	p->Send_string(info->server_name);
+	p->Send_string(info->server_revision);
+	p->Send_uint8 (info->server_lang);
+	p->Send_bool  (info->use_password);
+	p->Send_uint8 (info->clients_max);
+	p->Send_uint8 (info->clients_on);
+	p->Send_uint8 (info->spectators_on);
+	p->Send_string(info->map_name);
+	p->Send_uint32(info->map_width);
+	p->Send_uint32(info->map_height);
+	p->Send_uint8 (info->map_set);
+	p->Send_bool  (info->dedicated);
+
+	{
+		/* Only send the GRF Identification (GRF_ID and MD5 checksum) of
+		 * the GRFs that are needed, i.e. the ones that the server has
+		 * selected in the NewGRF GUI and not the ones that are used due
+		 * to the fact that they are in [newgrf-static] in openttd.cfg */
+		const GRFConfig *c;
+		uint count = 0;
+
+		/* Count number of GRFs to send information about */
+		for (c = info->grfconfig; c != NULL; c = c->next) {
+			if (!HasBit(c->flags, GCF_STATIC)) count++;
+		}
+		p->Send_uint32(count); // Send number of GRFs
+
+		/* Send actual GRF Identifications */
+		for (c = info->grfconfig; c != NULL; c = c->next) {
+			if (!HasBit(c->flags, GCF_STATIC)) {
+				this->SendGRFIdentifier(p, &c->ident);
+			}
+		}
+	}
+}
+
 /**
 * Deserializes the NetworkGameInfo struct from the packet
 * @param p    the packet to read the data from
@@ -288,6 +384,60 @@ void NetworkUDPSocketHandler::ReceiveNetworkGameInfo(Packet *p, NetworkGameInfo
 			if (info->map_set     >= NETWORK_NUM_LANDSCAPES) info->map_set     = 0;
 	}
 }
+/**
+ * Deserializes the NetworkGameInfo struct from the packet
+ * @param p    the packet to read the data from
+ * @param info the NetworkGameInfo to deserialize into
+ */
+void NetworkUDPSocketHandler::ReceiveNetworkGameInfoExtended(Packet *p, NetworkGameInfo *info)
+{
+	static const Date MAX_DATE = ConvertYMDToDate(MAX_YEAR, 11, 31); // December is month 11
+
+	const uint8 version = p->Recv_uint8();
+	if (version > 0) return; // Unknown version
+
+	info->game_info_version = 255;
+
+	info->game_date      = Clamp(p->Recv_uint32(), 0, MAX_DATE);
+	info->start_date     = Clamp(p->Recv_uint32(), 0, MAX_DATE);
+	info->companies_max  = p->Recv_uint8 ();
+	info->companies_on   = p->Recv_uint8 ();
+	info->spectators_max = p->Recv_uint8 ();
+	p->Recv_string(info->server_name,     sizeof(info->server_name));
+	p->Recv_string(info->server_revision, sizeof(info->server_revision));
+	info->server_lang    = p->Recv_uint8 ();
+	info->use_password   = p->Recv_bool  ();
+	info->clients_max    = p->Recv_uint8 ();
+	info->clients_on     = p->Recv_uint8 ();
+	info->spectators_on  = p->Recv_uint8 ();
+	p->Recv_string(info->map_name, sizeof(info->map_name));
+	info->map_width      = p->Recv_uint32();
+	info->map_height     = p->Recv_uint32();
+	info->map_set        = p->Recv_uint8 ();
+	info->dedicated      = p->Recv_bool  ();
+
+	{
+		GRFConfig **dst = &info->grfconfig;
+		uint i;
+		uint num_grfs = p->Recv_uint32();
+
+		/* Broken/bad data. It cannot have that many NewGRFs. */
+		if (num_grfs > MAX_NEWGRFS) return;
+
+		for (i = 0; i < num_grfs; i++) {
+			GRFConfig *c = new GRFConfig();
+			this->ReceiveGRFIdentifier(p, &c->ident);
+			this->HandleIncomingNetworkGameInfoGRFConfig(c);
+
+			/* Append GRFConfig to the list */
+			*dst = c;
+			dst = &c->next;
+		}
+	}
+
+	if (info->server_lang >= NETWORK_NUM_LANGUAGES)  info->server_lang = 0;
+	if (info->map_set     >= NETWORK_NUM_LANDSCAPES) info->map_set     = 0;
+}

 /**
 * Handle an incoming packets by sending it to the correct function.
@@ -317,6 +467,9 @@ void NetworkUDPSocketHandler::HandleUDPPacket(Packet *p, NetworkAddress *client_
 		case PACKET_UDP_SERVER_NEWGRFS:       this->Receive_SERVER_NEWGRFS(p, client_addr);       break;
 		case PACKET_UDP_MASTER_SESSION_KEY:   this->Receive_MASTER_SESSION_KEY(p, client_addr);   break;

+		case PACKET_UDP_EX_MULTI:             this->Receive_EX_MULTI(p, client_addr);             break;
+		case PACKET_UDP_EX_SERVER_RESPONSE:   this->Receive_EX_SERVER_RESPONSE(p, client_addr);   break;
+
 		default:
 			if (this->HasClientQuit()) {
 				DEBUG(net, 0, "[udp] received invalid packet type %d from %s", type, client_addr->GetAddressAsString());
@@ -327,6 +480,74 @@ void NetworkUDPSocketHandler::HandleUDPPacket(Packet *p, NetworkAddress *client_
 	}
 }

+void NetworkUDPSocketHandler::Receive_EX_MULTI(Packet *p, NetworkAddress *client_addr)
+{
+	uint64 token        = p->Recv_uint64();
+	uint8 index         = p->Recv_uint8 ();
+	uint8 total         = p->Recv_uint8 ();
+	uint16 payload_size = p->Recv_uint16();
+
+	DEBUG(net, 6, "[udp] received multi-part packet from %s: " OTTD_PRINTFHEX64 ", %u/%u, %u bytes",
+			client_addr->GetAddressAsString(), token, index, total, payload_size);
+
+	if (total == 0 || index >= total) return;
+	if (!p->CanReadFromPacket(payload_size)) return;
+
+	time_t cur_time = time(NULL);
+
+	auto add_to_fragment = [&](FragmentSet &fs) {
+		fs.fragments[index].assign((const char *) p->buffer + p->pos, payload_size);
+
+		uint total_payload = 0;
+		for (auto &frag : fs.fragments) {
+			if (!frag.size()) return;
+
+			total_payload += frag.size();
+		}
+
+		DEBUG(net, 6, "[udp] merged multi-part packet from %s: " OTTD_PRINTFHEX64 ", %u bytes",
+				client_addr->GetAddressAsString(), token, total_payload);
+
+		Packet merged(this);
+		for (auto &frag : fs.fragments) {
+			merged.Send_binary(frag.data(), frag.size());
+		}
+		merged.PrepareToRead();
+
+		/* If the size does not match the packet must be corrupted.
+		 * Otherwise it will be marked as corrupted later on. */
+		if (total_payload != merged.size) {
+			DEBUG(net, 1, "received an extended packet with mismatching size from %s, (%u, %u)",
+					client_addr->GetAddressAsString(), total_payload, merged.size);
+		} else {
+			this->HandleUDPPacket(&merged, client_addr);
+		}
+
+		fs = this->fragments.back();
+		this->fragments.pop_back();
+	};
+
+	uint i = 0;
+	while (i < this->fragments.size()) {
+		FragmentSet &fs = this->fragments[i];
+		if (fs.create_time < cur_time - 10) {
+			fs = this->fragments.back();
+			this->fragments.pop_back();
+			continue;
+		}
+
+		if (fs.token == token && fs.address == *client_addr && fs.fragments.size() == total) {
+			add_to_fragment(fs);
+			return;
+		}
+		i++;
+	}
+
+	this->fragments.push_back({ token, *client_addr, cur_time, {} });
+	this->fragments.back().fragments.resize(total);
+	add_to_fragment(this->fragments.back());
+}
+
 /**
 * Helper for logging receiving invalid packets.
 * @param type The received packet type.
@@ -339,6 +560,7 @@ void NetworkUDPSocketHandler::ReceiveInvalidPacket(PacketUDPType type, NetworkAd

 void NetworkUDPSocketHandler::Receive_CLIENT_FIND_SERVER(Packet *p, NetworkAddress *client_addr) { this->ReceiveInvalidPacket(PACKET_UDP_CLIENT_FIND_SERVER, client_addr); }
 void NetworkUDPSocketHandler::Receive_SERVER_RESPONSE(Packet *p, NetworkAddress *client_addr) { this->ReceiveInvalidPacket(PACKET_UDP_SERVER_RESPONSE, client_addr); }
+void NetworkUDPSocketHandler::Receive_EX_SERVER_RESPONSE(Packet *p, NetworkAddress *client_addr) { this->ReceiveInvalidPacket(PACKET_UDP_EX_SERVER_RESPONSE, client_addr); }
 void NetworkUDPSocketHandler::Receive_CLIENT_DETAIL_INFO(Packet *p, NetworkAddress *client_addr) { this->ReceiveInvalidPacket(PACKET_UDP_CLIENT_DETAIL_INFO, client_addr); }
 void NetworkUDPSocketHandler::Receive_SERVER_DETAIL_INFO(Packet *p, NetworkAddress *client_addr) { this->ReceiveInvalidPacket(PACKET_UDP_SERVER_DETAIL_INFO, client_addr); }
 void NetworkUDPSocketHandler::Receive_SERVER_REGISTER(Packet *p, NetworkAddress *client_addr) { this->ReceiveInvalidPacket(PACKET_UDP_SERVER_REGISTER, client_addr); }
--- a/src/network/core/udp.h
+++ b/src/network/core/udp.h
@@ -18,6 +18,10 @@
 #include "game.h"
 #include "packet.h"

+#include <vector>
+#include <string>
+#include <time.h>
+
 #ifdef ENABLE_NETWORK

 /** Enum with all types of UDP packets. The order MUST not be changed **/
@@ -34,7 +38,10 @@ enum PacketUDPType {
 	PACKET_UDP_CLIENT_GET_NEWGRFS,   ///< Requests the name for a list of GRFs (GRF_ID and MD5)
 	PACKET_UDP_SERVER_NEWGRFS,       ///< Sends the list of NewGRF's requested.
 	PACKET_UDP_MASTER_SESSION_KEY,   ///< Sends a fresh session key to the client
-	PACKET_UDP_END,                  ///< Must ALWAYS be on the end of this list!! (period)
+	PACKET_UDP_END,                  ///< Must ALWAYS be the last non-extended item in the list!! (period)
+
+	PACKET_UDP_EX_MULTI = 128,       ///< Extended/multi packet type
+	PACKET_UDP_EX_SERVER_RESPONSE,   ///< Reply of the game server with extended game information
 };

 /** The types of server lists we can get */
@@ -54,6 +61,16 @@ protected:
 	/** The opened sockets. */
 	SocketList sockets;

+	uint64 fragment_token;
+
+	struct FragmentSet {
+		uint64 token;
+		NetworkAddress address;
+		time_t create_time;
+		std::vector<std::string> fragments;
+	};
+	std::vector<FragmentSet> fragments;
+
 	NetworkRecvStatus CloseConnection(bool error = true);

 	void ReceiveInvalidPacket(PacketUDPType, NetworkAddress *client_addr);
@@ -106,6 +123,8 @@ protected:
 	 */
 	virtual void Receive_SERVER_RESPONSE(Packet *p, NetworkAddress *client_addr);

+	virtual void Receive_EX_SERVER_RESPONSE(Packet *p, NetworkAddress *client_addr);
+
 	/**
 	 * Query for detailed information about companies.
 	 * @param p           The received packet.
@@ -230,6 +249,8 @@ protected:
 	 * @param config the GRF to handle
 	 */
 	virtual void HandleIncomingNetworkGameInfoGRFConfig(GRFConfig *config) { NOT_REACHED(); }
+
+	virtual void Receive_EX_MULTI(Packet *p, NetworkAddress *client_addr);
 public:
 	NetworkUDPSocketHandler(NetworkAddressList *bind = NULL);

@@ -243,7 +264,9 @@ public:
 	void ReceivePackets();

 	void SendNetworkGameInfo(Packet *p, const NetworkGameInfo *info);
+	void SendNetworkGameInfoExtended(Packet *p, const NetworkGameInfo *info, uint16 version);
 	void ReceiveNetworkGameInfo(Packet *p, NetworkGameInfo *info);
+	void ReceiveNetworkGameInfoExtended(Packet *p, NetworkGameInfo *info);
 };

 #endif /* ENABLE_NETWORK */
--- a/src/network/network.cpp
+++ b/src/network/network.cpp
@@ -1124,9 +1124,9 @@ void NetworkShutDown()
 * Checks whether the given version string is compatible with our version.
 * @param other the version string to compare to
 */
-bool IsNetworkCompatibleVersion(const char *other)
+bool IsNetworkCompatibleVersion(const char *other, bool extended)
 {
-	return strncmp(_openttd_revision, other, NETWORK_REVISION_LENGTH - 1) == 0;
+	return strncmp(_openttd_revision, other, (extended ? NETWORK_LONG_REVISION_LENGTH : NETWORK_REVISION_LENGTH) - 1) == 0;
 }

 #endif /* ENABLE_NETWORK */
--- a/src/network/network_client.cpp
+++ b/src/network/network_client.cpp
@@ -27,6 +27,7 @@
 #include "../gfx_func.h"
 #include "../error.h"
 #include "../rev.h"
+#include "../fios.h"
 #include "network.h"
 #include "network_base.h"
 #include "network_client.h"
@@ -684,7 +685,8 @@ NetworkRecvStatus ClientNetworkGameSocketHandler::Receive_SERVER_CHECK_NEWGRFS(P
 {
 	if (this->status != STATUS_JOIN) return NETWORK_RECV_STATUS_MALFORMED_PACKET;

-	uint grf_count = p->Recv_uint8();
+	uint grf_count = p->Recv_uint32();
+	if (grf_count > MAX_NEWGRFS) return NETWORK_RECV_STATUS_MALFORMED_PACKET;
 	NetworkRecvStatus ret = NETWORK_RECV_STATUS_OKAY;

 	/* Check all GRFs */
--- a/src/network/network_gui.cpp
+++ b/src/network/network_gui.cpp
@@ -1179,10 +1179,6 @@ struct NetworkStartServerWindow : public Window {
 			}

 			case WID_NSS_GENERATE_GAME: // Start game
-				if (CountSelectedGRFs(_grfconfig_newgame) > NETWORK_MAX_GRF_COUNT) {
-					ShowErrorMessage(STR_NEWGRF_ERROR_TOO_MANY_NEWGRFS_LOADED, INVALID_STRING_ID, WL_ERROR);
-					break;
-				}
 				_is_network_server = true;
 				if (_ctrl_pressed) {
 					StartNewGameWithoutGUI(GENERATE_NEW_SEED);
--- a/src/network/network_internal.h
+++ b/src/network/network_internal.h
@@ -144,7 +144,7 @@ void NetworkAddServer(const char *b);
 void NetworkRebuildHostList();
 void UpdateNetworkGameWindow();

-bool IsNetworkCompatibleVersion(const char *version);
+bool IsNetworkCompatibleVersion(const char *version, bool extended = false);

 /* From network_command.cpp */
 /**
--- a/src/network/network_server.cpp
+++ b/src/network/network_server.cpp
@@ -481,7 +481,7 @@ NetworkRecvStatus ServerNetworkGameSocketHandler::SendNewGRFCheck()
 		if (!HasBit(c->flags, GCF_STATIC)) grf_count++;
 	}

-	p->Send_uint8 (grf_count);
+	p->Send_uint32 (grf_count);
 	for (c = _grfconfig; c != NULL; c = c->next) {
 		if (!HasBit(c->flags, GCF_STATIC)) this->SendGRFIdentifier(p, &c->ident);
 	}
--- a/src/network/network_udp.cpp
+++ b/src/network/network_udp.cpp
@@ -34,8 +34,13 @@

 #include "core/udp.h"

+#include <vector>
+
 #include "../safeguards.h"

+extern const uint8 _out_of_band_grf_md5[16] { 0x00, 0xB0, 0xC0, 0xDE, 0x00, 0x00, 0x00, 0x00, 0x00, 0xB0, 0xC0, 0xDE, 0x00, 0x00, 0x00, 0x00 };
+static const uint32 FIND_SERVER_EXTENDED_TOKEN = 0x2A49582A;
+
 /** Mutex for all out threaded udp resolution and such. */
 static ThreadMutex *_network_udp_mutex = ThreadMutex::New();

@@ -66,6 +71,15 @@ struct NetworkUDPQueryServerInfo : NetworkAddress {
 	}
 };

+static Packet PrepareUdpClientFindServerPacket()
+{
+	Packet p(PACKET_UDP_CLIENT_FIND_SERVER);
+	p.Send_uint32(FIND_SERVER_EXTENDED_TOKEN);
+	p.Send_uint16(0); // flags
+	p.Send_uint16(0); // version
+	return p;
+}
+
 /**
 * Helper function doing the actual work for querying the server.
 * @param address The address of the server.
@@ -84,7 +98,7 @@ static void NetworkUDPQueryServer(NetworkAddress *address, bool needs_mutex, boo

 	if (needs_mutex) _network_udp_mutex->BeginCritical();
 	/* Init the packet */
-	Packet p(PACKET_UDP_CLIENT_FIND_SERVER);
+	Packet p = PrepareUdpClientFindServerPacket();
 	if (_udp_client_socket != NULL) _udp_client_socket->SendPacket(&p, address);
 	if (needs_mutex) _network_udp_mutex->EndCritical();
 }
@@ -153,6 +167,7 @@ protected:
 	virtual void Receive_CLIENT_FIND_SERVER(Packet *p, NetworkAddress *client_addr);
 	virtual void Receive_CLIENT_DETAIL_INFO(Packet *p, NetworkAddress *client_addr);
 	virtual void Receive_CLIENT_GET_NEWGRFS(Packet *p, NetworkAddress *client_addr);
+	void Reply_CLIENT_FIND_SERVER_extended(Packet *p, NetworkAddress *client_addr, NetworkGameInfo *ngi);
 public:
 	/**
 	 * Create the socket.
@@ -192,6 +207,12 @@ void ServerNetworkUDPSocketHandler::Receive_CLIENT_FIND_SERVER(Packet *p, Networ
 	strecpy(ngi.map_name, _network_game_info.map_name, lastof(ngi.map_name));
 	strecpy(ngi.server_name, _settings_client.network.server_name, lastof(ngi.server_name));
 	strecpy(ngi.server_revision, _openttd_revision, lastof(ngi.server_revision));
+	strecpy(ngi.short_server_revision, _openttd_revision, lastof(ngi.short_server_revision));
+
+	if (p->CanReadFromPacket(8, true) && p->Recv_uint32() == FIND_SERVER_EXTENDED_TOKEN) {
+		this->Reply_CLIENT_FIND_SERVER_extended(p, client_addr, &ngi);
+		return;
+	}

 	Packet packet(PACKET_UDP_SERVER_RESPONSE);
 	this->SendNetworkGameInfo(&packet, &ngi);
@@ -202,6 +223,19 @@ void ServerNetworkUDPSocketHandler::Receive_CLIENT_FIND_SERVER(Packet *p, Networ
 	DEBUG(net, 2, "[udp] queried from %s", client_addr->GetHostname());
 }

+void ServerNetworkUDPSocketHandler::Reply_CLIENT_FIND_SERVER_extended(Packet *p, NetworkAddress *client_addr, NetworkGameInfo *ngi)
+{
+	uint16 version = p->Recv_uint16();
+
+	Packet packet(PACKET_UDP_EX_SERVER_RESPONSE);
+	this->SendNetworkGameInfoExtended(&packet, ngi, version);
+
+	/* Let the client know that we are here */
+	this->SendPacket(&packet, client_addr);
+
+	DEBUG(net, 2, "[udp] queried (extended: %u) from %s", version, client_addr->GetHostname());
+}
+
 void ServerNetworkUDPSocketHandler::Receive_CLIENT_DETAIL_INFO(Packet *p, NetworkAddress *client_addr)
 {
 	/* Just a fail-safe.. should never happen */
@@ -274,8 +308,12 @@ void ServerNetworkUDPSocketHandler::Receive_CLIENT_GET_NEWGRFS(Packet *p, Networ
 	uint8 num_grfs;
 	uint i;

-	const GRFConfig *in_reply[NETWORK_MAX_GRF_COUNT];
-	uint8 in_reply_count = 0;
+	struct GRFInfo {
+		GRFIdentifier ident;
+		const char *name = nullptr;
+	};
+	std::vector<GRFInfo> in_reply;
+
 	size_t packet_len = 0;

 	DEBUG(net, 6, "[udp] newgrf data request from %s", client_addr->GetAddressAsString());
@@ -284,37 +322,47 @@ void ServerNetworkUDPSocketHandler::Receive_CLIENT_GET_NEWGRFS(Packet *p, Networ
 	if (num_grfs > NETWORK_MAX_GRF_COUNT) return;

 	for (i = 0; i < num_grfs; i++) {
-		GRFIdentifier c;
+		GRFInfo info;
+		this->ReceiveGRFIdentifier(p, &info.ident);
+
+		if (memcmp(info.ident.md5sum, _out_of_band_grf_md5, 16) == 0) {
+			if (info.ident.grfid == 0x56D2B000) {
+				info.name = "=*=*= More than 62 GRFs in total =*=*=";
+			} else {
+				continue;
+			}
+		} else {
 			const GRFConfig *f;
-
-		this->ReceiveGRFIdentifier(p, &c);
-
 			/* Find the matching GRF file */
-		f = FindGRFConfig(c.grfid, FGCM_EXACT, c.md5sum);
+			f = FindGRFConfig(info.ident.grfid, FGCM_EXACT, info.ident.md5sum);
 			if (f == NULL) continue; // The GRF is unknown to this server

+			info.ident = f->ident;
+			info.name = f->GetName();
+		}
+
 		/* If the reply might exceed the size of the packet, only reply
 		 * the current list and do not send the other data.
 		 * The name could be an empty string, if so take the filename. */
-		packet_len += sizeof(c.grfid) + sizeof(c.md5sum) +
-				min(strlen(f->GetName()) + 1, (size_t)NETWORK_GRF_NAME_LENGTH);
+		packet_len += sizeof(info.ident.grfid) + sizeof(info.ident.md5sum) +
+				min(strlen(info.name) + 1, (size_t)NETWORK_GRF_NAME_LENGTH);
 		if (packet_len > SEND_MTU - 4) { // 4 is 3 byte header + grf count in reply
 			break;
 		}
-		in_reply[in_reply_count] = f;
-		in_reply_count++;
+
+		in_reply.push_back(info);
 	}

-	if (in_reply_count == 0) return;
+	if (in_reply.empty()) return;

 	Packet packet(PACKET_UDP_SERVER_NEWGRFS);
-	packet.Send_uint8(in_reply_count);
-	for (i = 0; i < in_reply_count; i++) {
+	packet.Send_uint8(in_reply.size());
+	for (const GRFInfo &info : in_reply) {
 		char name[NETWORK_GRF_NAME_LENGTH];

 		/* The name could be an empty string, if so take the filename */
-		strecpy(name, in_reply[i]->GetName(), lastof(name));
-		this->SendGRFIdentifier(&packet, &in_reply[i]->ident);
+		strecpy(name, info.name, lastof(name));
+		this->SendGRFIdentifier(&packet, &info.ident);
 		packet.Send_string(name);
 	}

@@ -325,8 +373,11 @@ void ServerNetworkUDPSocketHandler::Receive_CLIENT_GET_NEWGRFS(Packet *p, Networ

 /** Helper class for handling all client side communication. */
 class ClientNetworkUDPSocketHandler : public NetworkUDPSocketHandler {
+private:
+	void Receive_SERVER_RESPONSE_Common(Packet *p, NetworkAddress *client_addr, bool extended);
 protected:
 	virtual void Receive_SERVER_RESPONSE(Packet *p, NetworkAddress *client_addr);
+	virtual void Receive_EX_SERVER_RESPONSE(Packet *p, NetworkAddress *client_addr);
 	virtual void Receive_MASTER_RESPONSE_LIST(Packet *p, NetworkAddress *client_addr);
 	virtual void Receive_SERVER_NEWGRFS(Packet *p, NetworkAddress *client_addr);
 	virtual void HandleIncomingNetworkGameInfoGRFConfig(GRFConfig *config);
@@ -335,19 +386,33 @@ public:
 };

 void ClientNetworkUDPSocketHandler::Receive_SERVER_RESPONSE(Packet *p, NetworkAddress *client_addr)
+{
+	this->Receive_SERVER_RESPONSE_Common(p, client_addr, false);
+}
+
+void ClientNetworkUDPSocketHandler::Receive_EX_SERVER_RESPONSE(Packet *p, NetworkAddress *client_addr)
+{
+	this->Receive_SERVER_RESPONSE_Common(p, client_addr, true);
+}
+
+void ClientNetworkUDPSocketHandler::Receive_SERVER_RESPONSE_Common(Packet *p, NetworkAddress *client_addr, bool extended)
 {
 	NetworkGameList *item;

 	/* Just a fail-safe.. should never happen */
 	if (_network_udp_server) return;

-	DEBUG(net, 4, "[udp] server response from %s", client_addr->GetAddressAsString());
+	DEBUG(net, 4, "[udp]%s server response from %s", extended ? " extended" : "", client_addr->GetAddressAsString());

 	/* Find next item */
 	item = NetworkGameListAddItem(*client_addr);

 	ClearGRFConfigList(&item->info.grfconfig);
+	if (extended) {
+		this->ReceiveNetworkGameInfoExtended(p, &item->info);
+	} else {
 		this->ReceiveNetworkGameInfo(p, &item->info);
+	}

 	item->info.compatible = true;
 	{
@@ -362,14 +427,7 @@ void ClientNetworkUDPSocketHandler::Receive_SERVER_RESPONSE(Packet *p, NetworkAd
 		const GRFConfig *c;
 		uint in_request_count = 0;

-		for (c = item->info.grfconfig; c != NULL; c = c->next) {
-			if (c->status == GCS_NOT_FOUND) item->info.compatible = false;
-			if (c->status != GCS_NOT_FOUND || strcmp(c->GetName(), UNKNOWN_GRF_NAME_PLACEHOLDER) != 0) continue;
-			in_request[in_request_count] = c;
-			in_request_count++;
-		}
-
-		if (in_request_count > 0) {
+		auto flush_request = [&]() {
 			/* There are 'unknown' GRFs, now send a request for them */
 			uint i;
 			Packet packet(PACKET_UDP_CLIENT_GET_NEWGRFS);
@@ -380,7 +438,19 @@ void ClientNetworkUDPSocketHandler::Receive_SERVER_RESPONSE(Packet *p, NetworkAd
 			}

 			this->SendPacket(&packet, &item->address);
+
+			in_request_count = 0;
+		};
+
+		for (c = item->info.grfconfig; c != NULL; c = c->next) {
+			if (c->status == GCS_NOT_FOUND) item->info.compatible = false;
+			if (c->status != GCS_NOT_FOUND || strcmp(c->GetName(), UNKNOWN_GRF_NAME_PLACEHOLDER) != 0) continue;
+			in_request[in_request_count] = c;
+			in_request_count++;
+			if (in_request_count == NETWORK_MAX_GRF_COUNT) flush_request();
 		}
+
+		if (in_request_count > 0) flush_request();
 	}

 	if (item->info.hostname[0] == '\0') {
@@ -392,7 +462,7 @@ void ClientNetworkUDPSocketHandler::Receive_SERVER_RESPONSE(Packet *p, NetworkAd
 	}

 	/* Check if we are allowed on this server based on the revision-match */
-	item->info.version_compatible = IsNetworkCompatibleVersion(item->info.server_revision);
+	item->info.version_compatible = IsNetworkCompatibleVersion(item->info.server_revision, extended);
 	item->info.compatible &= item->info.version_compatible; // Already contains match for GRFs

 	item->online = true;
@@ -498,7 +568,7 @@ void ClientNetworkUDPSocketHandler::HandleIncomingNetworkGameInfoGRFConfig(GRFCo
 static void NetworkUDPBroadCast(NetworkUDPSocketHandler *socket)
 {
 	for (NetworkAddress *addr = _broadcast_list.Begin(); addr != _broadcast_list.End(); addr++) {
-		Packet p(PACKET_UDP_CLIENT_FIND_SERVER);
+		Packet p = PrepareUdpClientFindServerPacket();

 		DEBUG(net, 4, "[udp] broadcasting to %s", addr->GetHostname());

--- a/src/newgrf.cpp
+++ b/src/newgrf.cpp
@@ -9318,7 +9318,7 @@ void LoadNewGRF(uint load_index, uint file_index, uint num_baseset)
 			if (stage == GLS_LABELSCAN) InitNewGRFFile(c);

 			if (!HasBit(c->flags, GCF_STATIC) && !HasBit(c->flags, GCF_SYSTEM)) {
-				if ((_networking && num_non_static == NETWORK_MAX_GRF_COUNT) || slot == MAX_FILE_SLOTS) {
+				if (slot == MAX_FILE_SLOTS) {
 					DEBUG(grf, 0, "'%s' is not loaded as the maximum number of non-static GRFs has been reached", c->filename);
 					c->status = GCS_DISABLED;
 					c->error  = new GRFError(STR_NEWGRF_ERROR_MSG_FATAL, STR_NEWGRF_ERROR_TOO_MANY_NEWGRFS_LOADED);
--- a/src/openttd.cpp
+++ b/src/openttd.cpp
@@ -895,13 +895,6 @@ int openttd_main(int argc, char *argv[])
 	DriverFactoryBase::SelectDriver(musicdriver, Driver::DT_MUSIC);
 	free(musicdriver);

-	// Check if not too much GRFs are loaded for network game
-	if (dedicated && CountSelectedGRFs(_grfconfig) > NETWORK_MAX_GRF_COUNT) {
-		DEBUG(net, 0, "Too many GRF loaded. Max %d are allowed.\nExiting ...", NETWORK_MAX_GRF_COUNT);
-		ShutdownGame();
-		goto exit_normal;
-	}
-
 	/* Take our initial lock on whatever we might want to do! */
 	_modal_progress_paint_mutex->BeginCritical();
 	_modal_progress_work_mutex->BeginCritical();
--- a/src/saveload/afterload.cpp
+++ b/src/saveload/afterload.cpp
@@ -763,13 +763,6 @@ bool AfterLoadGame()
 		return false;
 	}

-	if (_networking && CountSelectedGRFs(_grfconfig) > NETWORK_MAX_GRF_COUNT) {
-		SetSaveLoadError(STR_NEWGRF_ERROR_TOO_MANY_NEWGRFS_LOADED);
-		/* Restore the signals */
-		ResetSignalHandlers();
-		return false;
-	}
-
 	/* The value of _date_fract got divided, so make sure that old games are converted correctly. */
 	if (IsSavegameVersionBefore(11, 1) || (IsSavegameVersionBefore(147) && _date_fract > DAY_TICKS)) _date_fract /= 885;