# Copyright (C) 2013 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. """ Internet Group Management Protocol(IGMP) packet parser/serializer [RFC 1112] IGMP v1 format:: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Version| Type | Unused | Checksum | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Group Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ [RFC 2236] IGMP v2 format:: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Max Resp Time | Checksum | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Group Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ [RFC 3376] IGMP v3 Membership Query format:: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 0x11 | Max Resp Code | Checksum | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Group Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Resv |S| QRV | QQIC | Number of Sources (N) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source Address [1] | +- -+ | Source Address [2] | +- . -+ . . . . . . +- -+ | Source Address [N] | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ IGMP v3 Membership Report format:: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 0x22 | Reserved | Checksum | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved | Number of Group Records (M) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | . . . Group Record [1] . . . | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | . . . Group Record [2] . . . | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | . | . . . | . | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | . . . Group Record [M] . . . | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Where each Group Record has the following internal format:: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Record Type | Aux Data Len | Number of Sources (N) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Multicast Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source Address [1] | +- -+ | Source Address [2] | +- -+ . . . . . . . . . +- -+ | Source Address [N] | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | . . . Auxiliary Data . . . | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ """ import struct from math import trunc from os_ken.lib import addrconv from os_ken.lib import stringify from os_ken.lib.packet import packet_base from os_ken.lib.packet import packet_utils IGMP_TYPE_QUERY = 0x11 IGMP_TYPE_REPORT_V1 = 0x12 IGMP_TYPE_REPORT_V2 = 0x16 IGMP_TYPE_LEAVE = 0x17 IGMP_TYPE_REPORT_V3 = 0x22 QUERY_RESPONSE_INTERVAL = 10.0 LAST_MEMBER_QUERY_INTERVAL = 1.0 MULTICAST_IP_ALL_HOST = '224.0.0.1' MULTICAST_MAC_ALL_HOST = '01:00:5e:00:00:01' # for types of IGMPv3 Report Group Records MODE_IS_INCLUDE = 1 MODE_IS_EXCLUDE = 2 CHANGE_TO_INCLUDE_MODE = 3 CHANGE_TO_EXCLUDE_MODE = 4 ALLOW_NEW_SOURCES = 5 BLOCK_OLD_SOURCES = 6 class igmp(packet_base.PacketBase): """ Internet Group Management Protocol(IGMP, RFC 1112, RFC 2236) header encoder/decoder class. http://www.ietf.org/rfc/rfc1112.txt http://www.ietf.org/rfc/rfc2236.txt An instance has the following attributes at least. Most of them are same to the on-wire counterparts but in host byte order. __init__ takes the corresponding args in this order. =============== ==================================================== Attribute Description =============== ==================================================== msgtype a message type for v2, or a combination of version and a message type for v1. maxresp max response time in unit of 1/10 second. it is meaningful only in Query Message. csum a check sum value. 0 means automatically-calculate when encoding. address a group address value. =============== ==================================================== """ _PACK_STR = '!BBH4s' _MIN_LEN = struct.calcsize(_PACK_STR) _TYPE = { 'ascii': [ 'address' ] } def __init__(self, msgtype=IGMP_TYPE_QUERY, maxresp=0, csum=0, address='0.0.0.0'): super(igmp, self).__init__() self.msgtype = msgtype self.maxresp = maxresp self.csum = csum self.address = address @classmethod def parser(cls, buf): assert cls._MIN_LEN <= len(buf) (msgtype, ) = struct.unpack_from('!B', buf) if (IGMP_TYPE_QUERY == msgtype and igmpv3_query.MIN_LEN <= len(buf)): (instance, subclass, rest,) = igmpv3_query.parser(buf) elif IGMP_TYPE_REPORT_V3 == msgtype: (instance, subclass, rest,) = igmpv3_report.parser(buf) else: (msgtype, maxresp, csum, address ) = struct.unpack_from(cls._PACK_STR, buf) instance = cls(msgtype, maxresp, csum, addrconv.ipv4.bin_to_text(address)) subclass = None rest = buf[cls._MIN_LEN:] return instance, subclass, rest def serialize(self, payload, prev): hdr = bytearray(struct.pack(self._PACK_STR, self.msgtype, trunc(self.maxresp), self.csum, addrconv.ipv4.text_to_bin(self.address))) if self.csum == 0: self.csum = packet_utils.checksum(hdr) struct.pack_into('!H', hdr, 2, self.csum) return hdr class igmpv3_query(igmp): """ Internet Group Management Protocol(IGMP, RFC 3376) Membership Query message encoder/decoder class. http://www.ietf.org/rfc/rfc3376.txt An instance has the following attributes at least. Most of them are same to the on-wire counterparts but in host byte order. __init__ takes the corresponding args in this order. .. tabularcolumns:: |l|L| =============== ==================================================== Attribute Description =============== ==================================================== msgtype a message type for v3. maxresp max response time in unit of 1/10 second. csum a check sum value. 0 means automatically-calculate when encoding. address a group address value. s_flg when set to 1, routers suppress the timer process. qrv robustness variable for a querier. qqic an interval time for a querier in unit of seconds. num a number of the multicast servers. srcs a list of IPv4 addresses of the multicast servers. =============== ==================================================== """ _PACK_STR = '!BBH4sBBH' _MIN_LEN = struct.calcsize(_PACK_STR) MIN_LEN = _MIN_LEN _TYPE = { 'ascii': [ 'address' ], 'asciilist': [ 'srcs' ] } def __init__(self, msgtype=IGMP_TYPE_QUERY, maxresp=100, csum=0, address='0.0.0.0', s_flg=0, qrv=2, qqic=0, num=0, srcs=None): super(igmpv3_query, self).__init__( msgtype, maxresp, csum, address) self.s_flg = s_flg self.qrv = qrv self.qqic = qqic self.num = num srcs = srcs or [] assert isinstance(srcs, list) for src in srcs: assert isinstance(src, str) self.srcs = srcs @classmethod def parser(cls, buf): (msgtype, maxresp, csum, address, s_qrv, qqic, num ) = struct.unpack_from(cls._PACK_STR, buf) s_flg = (s_qrv >> 3) & 0b1 qrv = s_qrv & 0b111 offset = cls._MIN_LEN srcs = [] while 0 < len(buf[offset:]) and num > len(srcs): assert 4 <= len(buf[offset:]) (src, ) = struct.unpack_from('4s', buf, offset) srcs.append(addrconv.ipv4.bin_to_text(src)) offset += 4 assert num == len(srcs) return (cls(msgtype, maxresp, csum, addrconv.ipv4.bin_to_text(address), s_flg, qrv, qqic, num, srcs), None, buf[offset:]) def serialize(self, payload, prev): s_qrv = self.s_flg << 3 | self.qrv buf = bytearray(struct.pack(self._PACK_STR, self.msgtype, trunc(self.maxresp), self.csum, addrconv.ipv4.text_to_bin(self.address), s_qrv, trunc(self.qqic), self.num)) for src in self.srcs: buf.extend(struct.pack('4s', addrconv.ipv4.text_to_bin(src))) if 0 == self.num: self.num = len(self.srcs) struct.pack_into('!H', buf, 10, self.num) if 0 == self.csum: self.csum = packet_utils.checksum(buf) struct.pack_into('!H', buf, 2, self.csum) return bytes(buf) def __len__(self): return self._MIN_LEN + len(self.srcs) * 4 class igmpv3_report(igmp): """ Internet Group Management Protocol(IGMP, RFC 3376) Membership Report message encoder/decoder class. http://www.ietf.org/rfc/rfc3376.txt An instance has the following attributes at least. Most of them are same to the on-wire counterparts but in host byte order. __init__ takes the corresponding args in this order. .. tabularcolumns:: |l|L| =============== ==================================================== Attribute Description =============== ==================================================== msgtype a message type for v3. csum a check sum value. 0 means automatically-calculate when encoding. record_num a number of the group records. records a list of os_ken.lib.packet.igmp.igmpv3_report_group. None if no records. =============== ==================================================== """ _PACK_STR = '!BxH2xH' _MIN_LEN = struct.calcsize(_PACK_STR) _class_prefixes = ['igmpv3_report_group'] def __init__(self, msgtype=IGMP_TYPE_REPORT_V3, csum=0, record_num=0, records=None): self.msgtype = msgtype self.csum = csum self.record_num = record_num records = records or [] assert isinstance(records, list) for record in records: assert isinstance(record, igmpv3_report_group) self.records = records @classmethod def parser(cls, buf): (msgtype, csum, record_num ) = struct.unpack_from(cls._PACK_STR, buf) offset = cls._MIN_LEN records = [] while 0 < len(buf[offset:]) and record_num > len(records): record = igmpv3_report_group.parser(buf[offset:]) records.append(record) offset += len(record) assert record_num == len(records) return (cls(msgtype, csum, record_num, records), None, buf[offset:]) def serialize(self, payload, prev): buf = bytearray(struct.pack(self._PACK_STR, self.msgtype, self.csum, self.record_num)) for record in self.records: buf.extend(record.serialize()) if 0 == self.record_num: self.record_num = len(self.records) struct.pack_into('!H', buf, 6, self.record_num) if 0 == self.csum: self.csum = packet_utils.checksum(buf) struct.pack_into('!H', buf, 2, self.csum) return bytes(buf) def __len__(self): records_len = 0 for record in self.records: records_len += len(record) return self._MIN_LEN + records_len class igmpv3_report_group(stringify.StringifyMixin): r""" Internet Group Management Protocol(IGMP, RFC 3376) Membership Report Group Record message encoder/decoder class. http://www.ietf.org/rfc/rfc3376.txt This is used with os_ken.lib.packet.igmp.igmpv3_report. An instance has the following attributes at least. Most of them are same to the on-wire counterparts but in host byte order. __init__ takes the corresponding args in this order. .. tabularcolumns:: |l|L| =============== ==================================================== Attribute Description =============== ==================================================== type\_ a group record type for v3. aux_len the length of the auxiliary data. num a number of the multicast servers. address a group address value. srcs a list of IPv4 addresses of the multicast servers. aux the auxiliary data. =============== ==================================================== """ _PACK_STR = '!BBH4s' _MIN_LEN = struct.calcsize(_PACK_STR) _TYPE = { 'ascii': [ 'address' ], 'asciilist': [ 'srcs' ] } def __init__(self, type_=0, aux_len=0, num=0, address='0.0.0.0', srcs=None, aux=None): self.type_ = type_ self.aux_len = aux_len self.num = num self.address = address srcs = srcs or [] assert isinstance(srcs, list) for src in srcs: assert isinstance(src, str) self.srcs = srcs self.aux = aux @classmethod def parser(cls, buf): (type_, aux_len, num, address ) = struct.unpack_from(cls._PACK_STR, buf) offset = cls._MIN_LEN srcs = [] while 0 < len(buf[offset:]) and num > len(srcs): assert 4 <= len(buf[offset:]) (src, ) = struct.unpack_from('4s', buf, offset) srcs.append(addrconv.ipv4.bin_to_text(src)) offset += 4 assert num == len(srcs) aux = None if aux_len: (aux, ) = struct.unpack_from('%ds' % (aux_len * 4), buf, offset) return cls(type_, aux_len, num, addrconv.ipv4.bin_to_text(address), srcs, aux) def serialize(self): buf = bytearray(struct.pack(self._PACK_STR, self.type_, self.aux_len, self.num, addrconv.ipv4.text_to_bin(self.address))) for src in self.srcs: buf.extend(struct.pack('4s', addrconv.ipv4.text_to_bin(src))) if 0 == self.num: self.num = len(self.srcs) struct.pack_into('!H', buf, 2, self.num) if self.aux is not None: mod = len(self.aux) % 4 if mod: self.aux += bytearray(4 - mod) self.aux = bytes(self.aux) buf.extend(self.aux) if 0 == self.aux_len: self.aux_len = len(self.aux) // 4 struct.pack_into('!B', buf, 1, self.aux_len) return bytes(buf) def __len__(self): return self._MIN_LEN + len(self.srcs) * 4 + self.aux_len * 4