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| -rw-r--r-- | ryu/lib/packet/bpdu.py | 473 |
1 files changed, 473 insertions, 0 deletions
diff --git a/ryu/lib/packet/bpdu.py b/ryu/lib/packet/bpdu.py new file mode 100644 index 00000000..8e31771b --- /dev/null +++ b/ryu/lib/packet/bpdu.py @@ -0,0 +1,473 @@ +# 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. + + +""" +Bridge Protocol Data Unit(BPDU, IEEE 802.1D) parser/serializer +http://standards.ieee.org/getieee802/download/802.1D-2004.pdf + + +Configuration BPDUs format + + +----------------------------------------------+---------+ + | Structure | Octet | + +==============================================+=========+ + | Protocol Identifier = 0000 0000 0000 0000 | 1 - 2 | + | | | + +----------------------------------------------+---------+ + | Protocol Version Identifier = 0000 0000 | 3 | + +----------------------------------------------+---------+ + | BPDU Type = 0000 0000 | 4 | + +----------------------------------------------+---------+ + | Flags | 5 | + +----------------------------------------------+---------+ + | Root Identifier | 6 - 13 | + | include - priority | | + | system ID extension | | + | MAC address | | + +----------------------------------------------+---------+ + | Root Path Cost | 14 - 17 | + | | | + +----------------------------------------------+---------+ + | Bridge Identifier | 18 - 25 | + | include - priority | | + | system ID extension | | + | MAC address | | + +----------------------------------------------+---------+ + | Port Identifier | 26 - 27 | + | include - priority | | + | port number | | + +----------------------------------------------+---------+ + | Message Age | 28 - 29 | + | | | + +----------------------------------------------+---------+ + | Max Age | 30 - 31 | + | | | + +----------------------------------------------+---------+ + | Hello Time | 32 - 33 | + | | | + +----------------------------------------------+---------+ + | Forward Delay | 34 - 35 | + | | | + +----------------------------------------------+---------+ + + +Topology Change NotificationBPDUs format + + +----------------------------------------------+---------+ + | Structure | Octet | + +==============================================+=========+ + | Protocol Identifier = 0000 0000 0000 0000 | 1 - 2 | + | | | + +----------------------------------------------+---------+ + | Protocol Version Identifier = 0000 0000 | 3 | + +----------------------------------------------+---------+ + | BPDU Type = 1000 0000 | 4 | + +----------------------------------------------+---------+ + + +Rapid Spanning Tree BPDUs(RST BPDUs) format + + +----------------------------------------------+---------+ + | Structure | Octet | + +==============================================+=========+ + | Protocol Identifier = 0000 0000 0000 0000 | 1 - 2 | + | | | + +----------------------------------------------+---------+ + | Protocol Version Identifier = 0000 0010 | 3 | + +----------------------------------------------+---------+ + | BPDU Type = 0000 0010 | 4 | + +----------------------------------------------+---------+ + | Flags | 5 | + +----------------------------------------------+---------+ + | Root Identifier | 6 - 13 | + | include - priority | | + | system ID extension | | + | MAC address | | + +----------------------------------------------+---------+ + | Root Path Cost | 14 - 17 | + | | | + +----------------------------------------------+---------+ + | Bridge Identifier | 18 - 25 | + | include - priority | | + | system ID extension | | + | MAC address | | + +----------------------------------------------+---------+ + | Port Identifier | 26 - 27 | + | include - priority | | + | port number | | + +----------------------------------------------+---------+ + | Message Age | 28 - 29 | + | | | + +----------------------------------------------+---------+ + | Max Age | 30 - 31 | + | | | + +----------------------------------------------+---------+ + | Hello Time | 32 - 33 | + | | | + +----------------------------------------------+---------+ + | Forward Delay | 34 - 35 | + | | | + +----------------------------------------------+---------+ + | Version 1 Length = 0000 0000 | 36 | + +----------------------------------------------+---------+ + +""" + + +import binascii +import struct +from . import packet_base +from ryu.lib.mac import haddr_to_bin + + +# BPDU destination +BRIDGE_GROUP_ADDRESS = '\x01\x80\xc2\x00\x00\x00' + + +PROTOCOL_IDENTIFIER = 0 +PROTOCOLVERSION_ID_BPDU = 0 +PROTOCOLVERSION_ID_RSTBPDU = 2 +TYPE_CONFIG_BPDU = 0 +TYPE_TOPOLOGY_CHANGE_BPDU = 128 +TYPE_RSTBPDU = 2 +DEFAULT_BRIDGE_PRIORITY = 32768 +DEFAULT_PORT_PRIORITY = 128 +DEFAULT_MAX_AGE = 20 +DEFAULT_HELLO_TIME = 2 +DEFAULT_FORWARD_DELAY = 15 +VERSION_1_LENGTH = 0 + + +class bpdu(packet_base.PacketBase): + """Bridge Protocol Data Unit(BPDU) header encoder/decoder base class. + """ + _PACK_STR = '!HBB' + _PACK_LEN = struct.calcsize(_PACK_STR) + _BPDU_TYPES = {} + + @staticmethod + def register_bpdu_type(sub_cls): + bpdu._BPDU_TYPES[sub_cls.BPDU_TYPE] = sub_cls + return sub_cls + + def __init__(self): + super(bpdu, self).__init__() + + assert hasattr(self, 'VERSION_ID') + assert hasattr(self, 'BPDU_TYPE') + + self.protocol_id = PROTOCOL_IDENTIFIER + self.version_id = self.VERSION_ID + self.bpdu_type = self.BPDU_TYPE + + if hasattr(self, 'check_parameters'): + self.check_parameters() + + @classmethod + def parser(cls, buf): + assert len(buf) >= cls._PACK_LEN + (protocol_id, version_id, + bpdu_type) = struct.unpack_from(cls._PACK_STR, buf) + assert protocol_id == PROTOCOL_IDENTIFIER + + bpdu_cls = cls._BPDU_TYPES.get(bpdu_type, None) + + if bpdu_cls: + assert version_id == bpdu_cls.VERSION_ID + assert len(buf[cls._PACK_LEN:]) >= bpdu_cls.PACK_LEN + return bpdu_cls.parser(buf[cls._PACK_LEN:]) + else: + # Unknown bdpu type. + return buf, None, None + + def serialize(self, payload, prev): + return struct.pack(bpdu._PACK_STR, self.protocol_id, + self.version_id, self.bpdu_type) + + +@bpdu.register_bpdu_type +class ConfigurationBPDUs(bpdu): + """Configuration BPDUs(IEEE 802.1D) 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 correspondig args in this order. + + ========================== =============================================== + Attribute Description + ========================== =============================================== + flags | Bit 1: Topology Change flag + | Bits 2 through 7: unused and take the value 0 + | Bit 8: Topology Change Acknowledgment flag + root_priority Root Identifier priority \ + set 0-61440 in steps of 4096 + root_system_id_extension Root Identifier system ID extension + root_mac_address Root Identifier MAC address + root_path_cost Root Path Cost + bridge_priority Bridge Identifier priority \ + set 0-61440 in steps of 4096 + bridge_system_id_extension Bridge Identifier system ID extension + bridge_mac_address Bridge Identifier MAC address + port_priority Port Identifier priority \ + set 0-240 in steps of 16 + port_number Port Identifier number + message_age Message Age timer value + max_age Max Age timer value + hello_time Hello Time timer value + forward_delay Forward Delay timer value + ========================== =============================================== + """ + + VERSION_ID = PROTOCOLVERSION_ID_BPDU + BPDU_TYPE = TYPE_CONFIG_BPDU + _PACK_STR = '!BQIQHHHHH' + PACK_LEN = struct.calcsize(_PACK_STR) + + _BRIDGE_PRIORITY_STEP = 4096 + _PORT_PRIORITY_STEP = 16 + _TIMER_STEP = float(1)/256 + + def __init__(self, flags=0, root_priority=DEFAULT_BRIDGE_PRIORITY, + root_system_id_extension=0, + root_mac_address=haddr_to_bin('00:00:00:00:00:00'), + root_path_cost=0, bridge_priority=DEFAULT_BRIDGE_PRIORITY, + bridge_system_id_extension=0, + bridge_mac_address=haddr_to_bin('00:00:00:00:00:00'), + port_priority=DEFAULT_PORT_PRIORITY, port_number=0, + message_age=0, max_age=DEFAULT_MAX_AGE, + hello_time=DEFAULT_HELLO_TIME, + forward_delay=DEFAULT_FORWARD_DELAY): + self.flags = flags + self.root_priority = root_priority + self.root_system_id_extension = root_system_id_extension + self.root_mac_address = root_mac_address + self.root_path_cost = root_path_cost + self.bridge_priority = bridge_priority + self.bridge_system_id_extension = bridge_system_id_extension + self.bridge_mac_address = bridge_mac_address + self.port_priority = port_priority + self.port_number = port_number + self.message_age = message_age + self.max_age = max_age + self.hello_time = hello_time + self.forward_delay = forward_delay + + super(ConfigurationBPDUs, self).__init__() + + def check_parameters(self): + assert (self.flags >> 1 & 0b111111) == 0 + assert self.root_priority % self._BRIDGE_PRIORITY_STEP == 0 + assert self.bridge_priority % self._BRIDGE_PRIORITY_STEP == 0 + assert self.port_priority % self._PORT_PRIORITY_STEP == 0 + assert self.message_age % self._TIMER_STEP == 0 + assert self.max_age % self._TIMER_STEP == 0 + assert self.hello_time % self._TIMER_STEP == 0 + assert self.forward_delay % self._TIMER_STEP == 0 + + @classmethod + def parser(cls, buf): + (flags, root_id, root_path_cost, bridge_id, + port_id, message_age, max_age, hello_time, + forward_delay) = struct.unpack_from(ConfigurationBPDUs._PACK_STR, buf) + + (root_priority, + root_system_id_extension, + root_mac_address) = cls._decode_bridge_id(root_id) + (bridge_priority, + bridge_system_id_extension, + bridge_mac_address) = cls._decode_bridge_id(bridge_id) + (port_priority, + port_number) = cls._decode_port_id(port_id) + + return (cls(flags, root_priority, root_system_id_extension, + root_mac_address, root_path_cost, + bridge_priority, bridge_system_id_extension, + bridge_mac_address, port_priority, port_number, + cls._decode_timer(message_age), + cls._decode_timer(max_age), + cls._decode_timer(hello_time), + cls._decode_timer(forward_delay)), + None, buf[ConfigurationBPDUs.PACK_LEN:]) + + def serialize(self, payload, prev): + base = super(ConfigurationBPDUs, self).serialize(payload, prev) + + root_id = self.encode_bridge_id(self.root_priority, + self.root_system_id_extension, + self.root_mac_address) + bridge_id = self.encode_bridge_id(self.bridge_priority, + self.bridge_system_id_extension, + self.bridge_mac_address) + port_id = self.encode_port_id(self.port_priority, + self.port_number) + sub = struct.pack(ConfigurationBPDUs._PACK_STR, + self.flags, + root_id, + self.root_path_cost, + bridge_id, + port_id, + self._encode_timer(self.message_age), + self._encode_timer(self.max_age), + self._encode_timer(self.hello_time), + self._encode_timer(self.forward_delay)) + + return base + sub + + @staticmethod + def _decode_bridge_id(bridge_id): + priority = (bridge_id >> 48) & 0xf000 + system_id_extension = (bridge_id >> 48) & 0xfff + mac_addr = bridge_id & 0xffffffffffff + + mac_addr_list = [format((mac_addr >> (8 * i)) & 0xff, '02x') + for i in range(0, 6)] + mac_addr_list.reverse() + mac_address = binascii.a2b_hex(''.join(mac_addr_list)) + + return priority, system_id_extension, mac_address + + @staticmethod + def encode_bridge_id(priority, system_id_extension, mac_address): + mac_addr = int(binascii.hexlify(mac_address), 16) + return ((priority + system_id_extension) << 48) + mac_addr + + @staticmethod + def _decode_port_id(port_id): + priority = port_id >> 8 & 0xf0 + port_number = port_id & 0xfff + return priority, port_number + + @staticmethod + def encode_port_id(priority, port_number): + return (priority << 8) + port_number + + @staticmethod + def _decode_timer(timer): + return timer / float(0x100) + + @staticmethod + def _encode_timer(timer): + return timer * 0x100 + + +@bpdu.register_bpdu_type +class TopologyChangeNotificationBPDUs(bpdu): + """Topology Change Notification BPDUs(IEEE 802.1D) + header encoder/decoder class. + """ + + VERSION_ID = PROTOCOLVERSION_ID_BPDU + BPDU_TYPE = TYPE_TOPOLOGY_CHANGE_BPDU + _PACK_STR = '' + PACK_LEN = struct.calcsize(_PACK_STR) + + def __init__(self): + super(TopologyChangeNotificationBPDUs, self).__init__() + + @classmethod + def parser(cls, buf): + return cls(), None, buf[bpdu._PACK_LEN:] + + +@bpdu.register_bpdu_type +class RstBPDUs(ConfigurationBPDUs): + """Rapid Spanning Tree BPDUs(RST BPDUs, IEEE 802.1D) + 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 correspondig args in this order. + + ========================== =========================================== + Attribute Description + ========================== =========================================== + flags | Bit 1: Topology Change flag + | Bit 2: Proposal flag + | Bits 3 and 4: Port Role + | Bit 5: Learning flag + | Bit 6: Forwarding flag + | Bit 7: Agreement flag + | Bit 8: Topology Change Acknowledgment flag + root_priority Root Identifier priority \ + set 0-61440 in steps of 4096 + root_system_id_extension Root Identifier system ID extension + root_mac_address Root Identifier MAC address + root_path_cost Root Path Cost + bridge_priority Bridge Identifier priority \ + set 0-61440 in steps of 4096 + bridge_system_id_extension Bridge Identifier system ID extension + bridge_mac_address Bridge Identifier MAC address + port_priority Port Identifier priority \ + set 0-240 in steps of 16 + port_number Port Identifier number + message_age Message Age timer value + max_age Max Age timer value + hello_time Hello Time timer value + forward_delay Forward Delay timer value + ========================== =========================================== + """ + + VERSION_ID = PROTOCOLVERSION_ID_RSTBPDU + BPDU_TYPE = TYPE_RSTBPDU + _PACK_STR = '!B' + PACK_LEN = struct.calcsize(_PACK_STR) + + def __init__(self, flags=0, root_priority=DEFAULT_BRIDGE_PRIORITY, + root_system_id_extension=0, + root_mac_address=haddr_to_bin('00:00:00:00:00:00'), + root_path_cost=0, bridge_priority=DEFAULT_BRIDGE_PRIORITY, + bridge_system_id_extension=0, + bridge_mac_address=haddr_to_bin('00:00:00:00:00:00'), + port_priority=DEFAULT_PORT_PRIORITY, port_number=0, + message_age=0, max_age=DEFAULT_MAX_AGE, + hello_time=DEFAULT_HELLO_TIME, + forward_delay=DEFAULT_FORWARD_DELAY): + self.version_1_length = VERSION_1_LENGTH + + super(RstBPDUs, self).__init__(flags, root_priority, + root_system_id_extension, + root_mac_address, root_path_cost, + bridge_priority, + bridge_system_id_extension, + bridge_mac_address, + port_priority, port_number, + message_age, max_age, + hello_time, forward_delay) + + def check_parameters(self): + assert self.root_priority % self._BRIDGE_PRIORITY_STEP == 0 + assert self.bridge_priority % self._BRIDGE_PRIORITY_STEP == 0 + assert self.port_priority % self._PORT_PRIORITY_STEP == 0 + assert self.message_age % self._TIMER_STEP == 0 + assert self.max_age % self._TIMER_STEP == 0 + assert self.hello_time % self._TIMER_STEP == 0 + assert self.forward_delay % self._TIMER_STEP == 0 + + @classmethod + def parser(cls, buf): + get_cls, next_type, buf = super(RstBPDUs, cls).parser(buf) + + (version_1_length,) = struct.unpack_from(RstBPDUs._PACK_STR, buf) + assert version_1_length == VERSION_1_LENGTH + + return get_cls, next_type, buf[RstBPDUs.PACK_LEN:] + + def serialize(self, payload, prev): + base = super(RstBPDUs, self).serialize(payload, prev) + sub = struct.pack(RstBPDUs._PACK_STR, self.version_1_length) + return base + sub |