dpkt/aim.py

# $Id: aim.py 23 2006-11-08 15:45:33Z dugsong $
# -*- coding: utf-8 -*-

"""AOL Instant Messenger."""
from __future__ import absolute_import

import struct

from . import dpkt

# OSCAR: http://iserverd1.khstu.ru/oscar/


class FLAP(dpkt.Packet):
    """Frame Layer Protocol.

    See more about the FLAP on \
    https://en.wikipedia.org/wiki/OSCAR_protocol#FLAP_header

    Attributes:
        __hdr__: Header fields of FLAP.
        data: Message data.
    """
    
    __hdr__ = (
        ('ast', 'B', 0x2a),  # '*'
        ('type', 'B', 0),
        ('seq', 'H', 0),
        ('len', 'H', 0)
    )

    def unpack(self, buf):
        dpkt.Packet.unpack(self, buf)
        if self.ast != 0x2a:
            raise dpkt.UnpackError('invalid FLAP header')
        if len(self.data) < self.len:
            raise dpkt.NeedData('%d left, %d needed' % (len(self.data), self.len))


class SNAC(dpkt.Packet):
    """Simple Network Atomic Communication.

    See more about the SNAC on \
    https://en.wikipedia.org/wiki/OSCAR_protocol#SNAC_data

    Attributes:
        __hdr__: Header fields of SNAC.
    """
    
    __hdr__ = (
        ('family', 'H', 0),
        ('subtype', 'H', 0),
        ('flags', 'H', 0),
        ('reqid', 'I', 0)
    )


def tlv(buf):
    n = 4
    try:
        t, l = struct.unpack('>HH', buf[:n])
    except struct.error:
        raise dpkt.UnpackError
    v = buf[n:n + l]
    if len(v) < l:
        raise dpkt.NeedData
    buf = buf[n + l:]
    return t, l, v, buf

# TOC 1.0: http://jamwt.com/Py-TOC/PROTOCOL

# TOC 2.0: http://www.firestuff.org/projects/firetalk/doc/toc2.txt