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Diffstat (limited to 'doc/packet_struct_notation.txt')
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diff --git a/doc/packet_struct_notation.txt b/doc/packet_struct_notation.txt new file mode 100644 index 000000000..4ba30cb00 --- /dev/null +++ b/doc/packet_struct_notation.txt @@ -0,0 +1,85 @@ +//===== Athena Doc ======================================== +//= Packet Structure Notation +//===== By ================================================ +//= Ai4rei +//===== Version =========================================== +//= 1.0 +//========================================================= +//= 1.0 - Initial version. +//===== Description ======================================= +//= Explanation how packets are and should be documented. +//========================================================= + +This document specifies how packets are and should be documented, to +keep packet structure comments consistent in the entire codebase. It +also serves as a guide to those, who are unfamiliar with the general +packet layout. + +All mentioned data types are assumed to be little-endian (least- +significant byte first, least significant bit last) and of same size +regardless of architecture. + += Typical description of a packet = + + /// Notifies the client about entering a chatroom (ZC_ENTER_ROOM). + /// 00db <packet len>.W <chat id>.L { <role>.L <name>.24B }* + /// role: + /// 0 = owner (menu) + /// 1 = normal + +The first line contain a brief description of what the packet does, +or what it is good for, followed by it's AEGIS name in parentheses; +first two letters of the AEGIS name specify origin (first letter) +and destination (second letter) of the packet. If the packet's name +is not known or is not applicable (eAthena server-server packets), +specify at least these two letters to indicate the direction of the +packet. Do not use S(end)/R(ecv) for this, as it is inaccurate and +location dependent (if the description is copied to different server +or other RO-related projects, it might change it's meaning). + +If there are multiple versions of the packet, the AEGIS name is +appended to the end of the packet's structure instead. If the name +did not change between versions, a PACKETVER expression is appended, +such as (PACKETVER >= 20111111). + +Second line describes the packet's field structure, beginning with a +%04x formatted packet type, followed by the individual fields and +their types. Each field begins with it's name enclosed in angle +brackets ( <field name> ) followed by a dot and the data size type. +Field names should be lower-case and without underscores. If other +packets already have a field in common, use that name, rather than +inventing your own (ex. "packet len" and "account id"). Repeated and +optional fields are designated with curly and square brackets +respectively, padded with a single space at each side. + +Further lines are optional and either include details about the +the packet's mechanics or further explanation on the packet fields' +values. + += Packet field data size type = + + B = 1 byte (byte) + W = 2 bytes (word) + L = 4 bytes (dword) + Q = 8 bytes (quad) + + nB = n bytes + ?B = variable/unknown amount of bytes + nS = n bytes, zero-terminated + ?S = variable/unknown amount of bytes, zero-terminated + += Repetition of packet fields = + + {} = repeated block + {}* = variable/unknown amount of consecutive blocks + {}*n = n times repeated block + [] = optional fields + += Packet origin and destination letters = + + A = Account (Login) + C = Client + H = Character + I = Inter + S = Server (any type of server) + Z = Zone (Map) |