# udp.h File Reference

Basic functions to receive and send UDP packets. More...

`#include "address.h"`
`#include "game.h"`
`#include "packet.h"`

Go to the source code of this file.

## Data Structures
class | NetworkUDPSocketHandler
| Base socket handler for all UDP sockets. More...
## Defines
#define | DECLARE_UDP_RECEIVE_COMMAND(type) virtual void NetworkPacketReceive_## type ##_command(Packet *p, NetworkAddress *client_addr)
#define | DEF_UDP_RECEIVE_COMMAND(cls, type) void cls ##NetworkUDPSocketHandler::NetworkPacketReceive_ ## type ## _command(Packet *p, NetworkAddress *client_addr)
## Enumerations
enum | PacketUDPType { PACKET_UDP_CLIENT_FIND_SERVER, PACKET_UDP_SERVER_RESPONSE, PACKET_UDP_CLIENT_DETAIL_INFO, PACKET_UDP_SERVER_DETAIL_INFO, PACKET_UDP_SERVER_REGISTER, PACKET_UDP_MASTER_ACK_REGISTER, PACKET_UDP_CLIENT_GET_LIST, PACKET_UDP_MASTER_RESPONSE_LIST, PACKET_UDP_SERVER_UNREGISTER, PACKET_UDP_CLIENT_GET_NEWGRFS, PACKET_UDP_SERVER_NEWGRFS, PACKET_UDP_MASTER_SESSION_KEY, PACKET_UDP_END }
| Enum with all types of UDP packets. More...
enum | ServerListType { SLT_IPv4 = 0, SLT_IPv6 = 1, SLT_AUTODETECT, SLT_END = SLT_AUTODETECT }
| The types of server lists we can get. More...

## Detailed Description

Basic functions to receive and send UDP packets.

*** Requesting game information from a server ***

This describes the on-the-wire structure of the request and reply packet of the NetworkGameInfo (see game.h) data.

--- Points of attention ---

- all > 1 byte integral values are written in little endian, unless specified otherwise. Thus, 0x01234567 would be sent as {0x67, 0x45, 0x23, 0x01}.
- all sent strings are of variable length and terminated by a ''. Thus, the length of the strings is not sent.
- years that are leap years in the 'days since X' to 'date' calculations: (year % 4 == 0) and ((year % 100 != 0) or (year % 400 == 0))

--- Request --- Bytes: Description: 2 size of the whole packet, in this case 3 1 type of packet, in this case PACKET_UDP_CLIENT_FIND_SERVER (0) This packet would look like: { 0x03, 0x00, 0x00 }

--- Reply --- Version: Bytes: Description: all 2 size of the whole packet all 1 type of packet, in this case PACKET_UDP_SERVER_RESPONSE (1) all 1 the version of this packet's structure

4+ 1 number of GRFs attached (n) 4+ n * 20 unique identifier for GRF files. Constists of:

- one 4 byte variable with the GRF ID
- 16 bytes (sent sequentially) for the MD5 checksum of the GRF

3+ 4 current game date in days since 1-1-0 (DMY) 3+ 4 game introduction date in days since 1-1-0 (DMY)

2+ 1 maximum number of companies allowed on the server 2+ 1 number of companies on the server 2+ 1 maximum number of spectators allowed on the server

1+ var string with the name of the server 1+ var string with the revision of the server 1+ 1 the language run on the server (0 = any, 1 = English, 2 = German, 3 = French) 1+ 1 whether the server uses a password (0 = no, 1 = yes) 1+ 1 maximum number of clients allowed on the server 1+ 1 number of clients on the server 1+ 1 number of spectators on the server 1 & 2 2 current game date in days since 1-1-1920 (DMY) 1 & 2 2 game introduction date in days since 1-1-1920 (DMY) 1+ var string with the name of the map 1+ 2 width of the map in tiles 1+ 2 height of the map in tiles 1+ 1 type of map: (0 = temperate, 1 = arctic, 2 = desert, 3 = toyland) 1+ 1 whether the server is dedicated (0 = no, 1 = yes)

Definition in file udp.h.

## Enumeration Type Documentation

enum PacketUDPType

Enum with all types of UDP packets.

The order MUST not be changed

Enumerator:

  PACKET_UDP_CLIENT_FIND_SERVER | Queries a game server for game information.
  PACKET_UDP_SERVER_RESPONSE | Reply of the game server with game information.
  PACKET_UDP_CLIENT_DETAIL_INFO | Queries a game server about details of the game, such as companies.
  PACKET_UDP_SERVER_DETAIL_INFO | Reply of the game server about details of the game, such as companies.
  PACKET_UDP_SERVER_REGISTER | Packet to register itself to the master server.
  PACKET_UDP_MASTER_ACK_REGISTER | Packet indicating registration has succedeed.
  PACKET_UDP_CLIENT_GET_LIST | Request for serverlist from master server.
  PACKET_UDP_MASTER_RESPONSE_LIST | Response from master server with server ip's + port's.
  PACKET_UDP_SERVER_UNREGISTER | Request to be removed from the server-list.
  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).

Definition at line 81 of file udp.h.

enum ServerListType

The types of server lists we can get.

Enumerator:

  SLT_IPv4 | Get the IPv4 addresses.
  SLT_IPv6 | Get the IPv6 addresses.
  SLT_AUTODETECT | Autodetect the type based on the connection.
  SLT_END | End of 'arrays' marker.

Definition at line 98 of file udp.h.