15  *

    16  *

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

    18  *

    19  * This describes the on-the-wire structure of the request and reply

    20  * packet of the NetworkGameInfo (see game.h) data.

    21  *

    22  * --- Points of attention ---

    23  *  - all > 1 byte integral values are written in little endian,

    24  *    unless specified otherwise.

    25  *      Thus, 0x01234567 would be sent as {0x67, 0x45, 0x23, 0x01}.

    26  *  - all sent strings are of variable length and terminated by a '\0'.

    27  *      Thus, the length of the strings is not sent.

    28  *  - years that are leap years in the 'days since X' to 'date' calculations:

    29  *     (year % 4 == 0) and ((year % 100 != 0) or (year % 400 == 0))

    30  *

    31  * --- Request ---

    32  * Bytes:  Description:

    33  *   2       size of the whole packet, in this case 3

    34  *   1       type of packet, in this case PACKET_UDP_CLIENT_FIND_SERVER (0)

    35  * This packet would look like: { 0x03, 0x00, 0x00 }

    36  *

    37  * --- Reply ---

    38  * Version: Bytes:  Description:

    39  *   all      2       size of the whole packet

    40  *   all      1       type of packet, in this case PACKET_UDP_SERVER_RESPONSE (1)

    41  *   all      1       the version of this packet's structure

    42  *

    43  *   4+       1       number of GRFs attached (n)

    44  *   4+       n * 20  unique identifier for GRF files. Constists of:

    45  *                     - one 4 byte variable with the GRF ID

    46  *                     - 16 bytes (sent sequentially) for the MD5 checksum

    47  *                       of the GRF

    48  *

    49  *   3+       4       current game date in days since 1-1-0 (DMY)

    50  *   3+       4       game introduction date in days since 1-1-0 (DMY)

    51  *

    52  *   2+       1       maximum number of companies allowed on the server

    53  *   2+       1       number of companies on the server

    54  *   2+       1       maximum number of spectators allowed on the server

    55  *

    56  *   1+       var     string with the name of the server

    57  *   1+       var     string with the revision of the server

    58  *   1+       1       the language run on the server

    59  *                    (0 = any, 1 = English, 2 = German, 3 = French)

    60  *   1+       1       whether the server uses a password (0 = no, 1 = yes)

    61  *   1+       1       maximum number of clients allowed on the server

    62  *   1+       1       number of clients on the server

    63  *   1+       1       number of spectators on the server

    64  *   1 & 2    2       current game date in days since 1-1-1920 (DMY)

    65  *   1 & 2    2       game introduction date in days since 1-1-1920 (DMY)

    66  *   1+       var     string with the name of the map

    67  *   1+       2       width of the map in tiles

    68  *   1+       2       height of the map in tiles

    69  *   1+       1       type of map:

    70  *                    (0 = temperate, 1 = arctic, 2 = desert, 3 = toyland)

    71  *   1+       1       whether the server is dedicated (0 = no, 1 = yes)