deb-ryu/ryu/lib/packet/icmp.py
Yuichi Ito 3731f46ba2 packet lib: icmp: fix reversibility about json
although ICMP is using internal classes, no class is registered into '_class_prefixes'.
therefore, from_jsondict() does not work correctly.
this patch makes from_jsondict() to work correctly by registering internal classes into '_class_prefixes'.

examination code:

    from ryu.lib.packet import icmp
    msg1 = icmp.icmp(data=icmp.echo())
    print msg1
    jsondict = msg1.to_jsondict()
    msg2 = icmp.icmp.from_jsondict(jsondict['icmp'])
    print msg2
    print str(msg1) == str(msg2)

before applying this patch:

    icmp(code=0,csum=0,data=echo(data=None,id=0,seq=0),type=8)
    icmp(code=0,csum=0,data={'echo': {'data': None, 'id': 0, 'seq': 0}},type=8)
    False

after applying this patch:

    icmp(code=0,csum=0,data=echo(data=None,id=0,seq=0),type=8)
    icmp(code=0,csum=0,data=echo(data=None,id=0,seq=0),type=8)
    True

Signed-off-by: Yuichi Ito <ito.yuichi0@gmail.com>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
2013-12-12 18:21:50 +09:00

306 lines
9.0 KiB
Python

# Copyright (C) 2012 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 packet_utils
from ryu.lib import stringify
ICMP_ECHO_REPLY = 0
ICMP_DEST_UNREACH = 3
ICMP_SRC_QUENCH = 4
ICMP_REDIRECT = 5
ICMP_ECHO_REQUEST = 8
ICMP_TIME_EXCEEDED = 11
ICMP_ECHO_REPLY_CODE = 0
ICMP_HOST_UNREACH_CODE = 1
ICMP_PORT_UNREACH_CODE = 3
ICMP_TTL_EXPIRED_CODE = 0
class icmp(packet_base.PacketBase):
"""ICMP (RFC 792) header encoder/decoder class.
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 Type
code Code
csum CheckSum \
(0 means automatically-calculate when encoding)
data Payload. \
Either a bytearray, or \
ryu.lib.packet.icmp.echo or \
ryu.lib.packet.icmp.dest_unreach or \
ryu.lib.packet.icmp.TimeExceeded object \
NOTE for icmp.echo: \
This includes "unused" 16 bits and the following \
"Internet Header + 64 bits of Original Data Datagram" of \
the ICMP header. \
NOTE for icmp.dest_unreach and icmp.TimeExceeded: \
This includes "unused" 8 or 24 bits and the following \
"Internet Header + leading octets of original datagram" \
of the original packet.
============== ====================
"""
_PACK_STR = '!BBH'
_MIN_LEN = struct.calcsize(_PACK_STR)
_ICMP_TYPES = {}
@staticmethod
def register_icmp_type(*args):
def _register_icmp_type(cls):
for type_ in args:
icmp._ICMP_TYPES[type_] = cls
return cls
return _register_icmp_type
def __init__(self, type_=ICMP_ECHO_REQUEST, code=0, csum=0, data=None):
super(icmp, self).__init__()
self.type = type_
self.code = code
self.csum = csum
self.data = data
@classmethod
def parser(cls, buf):
(type_, code, csum) = struct.unpack_from(cls._PACK_STR, buf)
msg = cls(type_, code, csum)
offset = cls._MIN_LEN
if len(buf) > offset:
cls_ = cls._ICMP_TYPES.get(type_, None)
if cls_:
msg.data = cls_.parser(buf, offset)
else:
msg.data = buf[offset:]
return msg, None, None
def serialize(self, payload, prev):
hdr = bytearray(struct.pack(icmp._PACK_STR, self.type,
self.code, self.csum))
if self.data is not None:
if self.type in icmp._ICMP_TYPES:
hdr += self.data.serialize()
else:
hdr += self.data
else:
self.data = echo()
hdr += self.data.serialize()
if self.csum == 0:
self.csum = packet_utils.checksum(hdr)
struct.pack_into('!H', hdr, 2, self.csum)
return hdr
def __len__(self):
return self._MIN_LEN + len(self.data)
@icmp.register_icmp_type(ICMP_ECHO_REPLY, ICMP_ECHO_REQUEST)
class echo(stringify.StringifyMixin):
"""ICMP sub encoder/decoder class for Echo and Echo Reply messages.
This is used with ryu.lib.packet.icmp.icmp for
ICMP Echo and Echo Reply messages.
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
============== ====================
id Identifier
seq Sequence Number
data Internet Header + 64 bits of Original Data Datagram
============== ====================
"""
_PACK_STR = '!HH'
_MIN_LEN = struct.calcsize(_PACK_STR)
def __init__(self, id_=0, seq=0, data=None):
super(echo, self).__init__()
self.id = id_
self.seq = seq
self.data = data
@classmethod
def parser(cls, buf, offset):
(id_, seq) = struct.unpack_from(cls._PACK_STR, buf, offset)
msg = cls(id_, seq)
offset += cls._MIN_LEN
if len(buf) > offset:
msg.data = buf[offset:]
return msg
def serialize(self):
hdr = bytearray(struct.pack(echo._PACK_STR, self.id,
self.seq))
if self.data is not None:
hdr += self.data
return hdr
def __len__(self):
length = self._MIN_LEN
if self.data is not None:
length += len(self.data)
return length
@icmp.register_icmp_type(ICMP_DEST_UNREACH)
class dest_unreach(stringify.StringifyMixin):
"""ICMP sub encoder/decoder class for Destination Unreachable Message.
This is used with ryu.lib.packet.icmp.icmp for
ICMP Destination Unreachable Message.
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.
[RFC1191] reserves bits for the "Next-Hop MTU" field.
[RFC4884] introduced 8-bit data length attribute.
.. tabularcolumns:: |l|p{35em}|
============== =====================================================
Attribute Description
============== =====================================================
data_len data length
mtu Next-Hop MTU
NOTE: This field is required when icmp code is 4
code 4 = fragmentation needed and DF set
data Internet Header + leading octets of original datagram
============== =====================================================
"""
_PACK_STR = '!xBH'
_MIN_LEN = struct.calcsize(_PACK_STR)
def __init__(self, data_len=0, mtu=0, data=None):
super(dest_unreach, self).__init__()
self.data_len = data_len
self.mtu = mtu
self.data = data
@classmethod
def parser(cls, buf, offset):
(data_len, mtu) = struct.unpack_from(cls._PACK_STR,
buf, offset)
msg = cls(data_len, mtu)
offset += cls._MIN_LEN
if len(buf) > offset:
msg.data = buf[offset:]
return msg
def serialize(self):
hdr = bytearray(struct.pack(dest_unreach._PACK_STR,
self.data_len, self.mtu))
if self.data is not None:
hdr += self.data
return hdr
def __len__(self):
length = self._MIN_LEN
if self.data is not None:
length += len(self.data)
return length
@icmp.register_icmp_type(ICMP_TIME_EXCEEDED)
class TimeExceeded(stringify.StringifyMixin):
"""ICMP sub encoder/decoder class for Time Exceeded Message.
This is used with ryu.lib.packet.icmp.icmp for
ICMP Time Exceeded Message.
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.
[RFC4884] introduced 8-bit data length attribute.
.. tabularcolumns:: |l|L|
============== ====================
Attribute Description
============== ====================
data_len data length
data Internet Header + leading octets of original datagram
============== ====================
"""
_PACK_STR = '!xBxx'
_MIN_LEN = struct.calcsize(_PACK_STR)
def __init__(self, data_len=0, data=None):
self.data_len = data_len
self.data = data
@classmethod
def parser(cls, buf, offset):
(data_len, ) = struct.unpack_from(cls._PACK_STR, buf, offset)
msg = cls(data_len)
offset += cls._MIN_LEN
if len(buf) > offset:
msg.data = buf[offset:]
return msg
def serialize(self):
hdr = bytearray(struct.pack(TimeExceeded._PACK_STR, self.data_len))
if self.data is not None:
hdr += self.data
return hdr
def __len__(self):
length = self._MIN_LEN
if self.data is not None:
length += len(self.data)
return length
icmp.set_classes(icmp._ICMP_TYPES)