# Copyright (C) 2014 Nippon Telegraph and Telephone Corporation.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
# implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import struct
from . import packet_base
from . import vlan
from . import mpls
from . import ether_types as ether
from os_ken.lib import addrconv


class linuxcooked(packet_base.PacketBase):
    _PACK_STR = '!HHH8sH'
    _MIN_LEN = struct.calcsize(_PACK_STR)

    def __init__(self, pkt_type, arphrd_type, address_length, address,
                 proto_type):
        super(linuxcooked, self).__init__()
        self.pkt_type = pkt_type
        self.arphrd_type = arphrd_type
        self.address_length = address_length
        self.address = address
        self.proto_type = proto_type

    @classmethod
    def parser(cls, buf):
        (pkt_type, arphrd_type, address_length, addres,
         proto_type) = struct.unpack_from(cls._PACK_STR, buf)
        l = cls(pkt_type, arphrd_type, address_length, addres, proto_type)
        return (l, linuxcooked.get_packet_type(proto_type),
                buf[linuxcooked._MIN_LEN:])

    @classmethod
    def get_packet_type(cls, type_):
        """Override method for the ethernet IEEE802.3 Length/Type
        field (self.ethertype).

        If the value of Length/Type field is less than or equal to
        1500 decimal(05DC hexadecimal), it means Length interpretation
        and be passed to the LLC sublayer."""
        if type_ <= ether.ETH_TYPE_IEEE802_3:
            type_ = ether.ETH_TYPE_IEEE802_3
        return cls._TYPES.get(type_)


# copy vlan _TYPES
linuxcooked._TYPES = vlan.vlan._TYPES
linuxcooked.register_packet_type(vlan.vlan, ether.ETH_TYPE_8021Q)
linuxcooked.register_packet_type(vlan.svlan, ether.ETH_TYPE_8021AD)
linuxcooked.register_packet_type(mpls.mpls, ether.ETH_TYPE_MPLS)