--- /dev/null
+# 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 abc
+import struct
+
+import six
+
+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=b''):
+ 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:
+ if self.type in icmp._ICMP_TYPES:
+ assert isinstance(self.data, _ICMPv4Payload)
+ 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)
+
+
+@six.add_metaclass(abc.ABCMeta)
+class _ICMPv4Payload(stringify.StringifyMixin):
+ """
+ Base class for the payload of ICMPv4 packet.
+ """
+
+
+@icmp.register_icmp_type(ICMP_ECHO_REPLY, ICMP_ECHO_REQUEST)
+class echo(_ICMPv4Payload):
+ """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(_ICMPv4Payload):
+ """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__()
+
+ if ((data_len >= 0) and (data_len <= 255)):
+ self.data_len = data_len
+ else:
+ raise ValueError('Specified data length (%d) is invalid.' % 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(_ICMPv4Payload):
+ """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):
+ if (data_len >= 0) and (data_len <= 255):
+ self.data_len = data_len
+ else:
+ raise ValueError('Specified data length (%d) is invalid.' % 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)
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