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|
# 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
|
