ryu/ryu/lib/packet/bpdu.py

   1 # Copyright (C) 2013 Nippon Telegraph and Telephone Corporation.
   2 #
   3 # Licensed under the Apache License, Version 2.0 (the "License");
   4 # you may not use this file except in compliance with the License.
   5 # You may obtain a copy of the License at
   6 #
   7 #    http://www.apache.org/licenses/LICENSE-2.0
   8 #
   9 # Unless required by applicable law or agreed to in writing, software
  10 # distributed under the License is distributed on an "AS IS" BASIS,
  11 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
  12 # implied.
  13 # See the License for the specific language governing permissions and
  14 # limitations under the License.
  15
  16
  17 """
  18 Bridge Protocol Data Unit(BPDU, IEEE 802.1D) parser/serializer
  19 http://standards.ieee.org/getieee802/download/802.1D-2004.pdf
  20
  21
  22 Configuration BPDUs format
  23
  24     +----------------------------------------------+---------+
  25     |                  Structure                   |  Octet  |
  26     +==============================================+=========+
  27     | Protocol Identifier = 0000 0000 0000 0000    |  1 - 2  |
  28     |                                              |         |
  29     +----------------------------------------------+---------+
  30     | Protocol Version Identifier = 0000 0000      |  3      |
  31     +----------------------------------------------+---------+
  32     | BPDU Type = 0000 0000                        |  4      |
  33     +----------------------------------------------+---------+
  34     | Flags                                        |  5      |
  35     +----------------------------------------------+---------+
  36     | Root Identifier                              |  6 - 13 |
  37     |  include - priority                          |         |
  38     |            system ID extension               |         |
  39     |            MAC address                       |         |
  40     +----------------------------------------------+---------+
  41     | Root Path Cost                               | 14 - 17 |
  42     |                                              |         |
  43     +----------------------------------------------+---------+
  44     | Bridge Identifier                            | 18 - 25 |
  45     |  include - priority                          |         |
  46     |            system ID extension               |         |
  47     |            MAC address                       |         |
  48     +----------------------------------------------+---------+
  49     | Port Identifier                              | 26 - 27 |
  50     |  include - priority                          |         |
  51     |            port number                       |         |
  52     +----------------------------------------------+---------+
  53     | Message Age                                  | 28 - 29 |
  54     |                                              |         |
  55     +----------------------------------------------+---------+
  56     | Max Age                                      | 30 - 31 |
  57     |                                              |         |
  58     +----------------------------------------------+---------+
  59     | Hello Time                                   | 32 - 33 |
  60     |                                              |         |
  61     +----------------------------------------------+---------+
  62     | Forward Delay                                | 34 - 35 |
  63     |                                              |         |
  64     +----------------------------------------------+---------+
  65
  66
  67 Topology Change NotificationBPDUs format
  68
  69     +----------------------------------------------+---------+
  70     |                  Structure                   |  Octet  |
  71     +==============================================+=========+
  72     | Protocol Identifier = 0000 0000 0000 0000    |  1 - 2  |
  73     |                                              |         |
  74     +----------------------------------------------+---------+
  75     | Protocol Version Identifier = 0000 0000      |  3      |
  76     +----------------------------------------------+---------+
  77     | BPDU Type = 1000 0000                        |  4      |
  78     +----------------------------------------------+---------+
  79
  80
  81 Rapid Spanning Tree BPDUs(RST BPDUs) format
  82
  83     +----------------------------------------------+---------+
  84     |                  Structure                   |  Octet  |
  85     +==============================================+=========+
  86     | Protocol Identifier = 0000 0000 0000 0000    |  1 - 2  |
  87     |                                              |         |
  88     +----------------------------------------------+---------+
  89     | Protocol Version Identifier = 0000 0010      |  3      |
  90     +----------------------------------------------+---------+
  91     | BPDU Type = 0000 0010                        |  4      |
  92     +----------------------------------------------+---------+
  93     | Flags                                        |  5      |
  94     +----------------------------------------------+---------+
  95     | Root Identifier                              |  6 - 13 |
  96     |  include - priority                          |         |
  97     |            system ID extension               |         |
  98     |            MAC address                       |         |
  99     +----------------------------------------------+---------+
 100     | Root Path Cost                               | 14 - 17 |
 101     |                                              |         |
 102     +----------------------------------------------+---------+
 103     | Bridge Identifier                            | 18 - 25 |
 104     |  include - priority                          |         |
 105     |            system ID extension               |         |
 106     |            MAC address                       |         |
 107     +----------------------------------------------+---------+
 108     | Port Identifier                              | 26 - 27 |
 109     |  include - priority                          |         |
 110     |            port number                       |         |
 111     +----------------------------------------------+---------+
 112     | Message Age                                  | 28 - 29 |
 113     |                                              |         |
 114     +----------------------------------------------+---------+
 115     | Max Age                                      | 30 - 31 |
 116     |                                              |         |
 117     +----------------------------------------------+---------+
 118     | Hello Time                                   | 32 - 33 |
 119     |                                              |         |
 120     +----------------------------------------------+---------+
 121     | Forward Delay                                | 34 - 35 |
 122     |                                              |         |
 123     +----------------------------------------------+---------+
 124     | Version 1 Length = 0000 0000                 | 36      |
 125     +----------------------------------------------+---------+
 126
 127 """
 128
 129
 130 import binascii
 131 import struct
 132 from . import packet_base
 133 from ryu.lib import addrconv
 134
 135
 136 # BPDU destination
 137 BRIDGE_GROUP_ADDRESS = '01:80:c2:00:00:00'
 138
 139
 140 PROTOCOL_IDENTIFIER = 0
 141 PROTOCOLVERSION_ID_BPDU = 0
 142 PROTOCOLVERSION_ID_RSTBPDU = 2
 143 TYPE_CONFIG_BPDU = 0
 144 TYPE_TOPOLOGY_CHANGE_BPDU = 128
 145 TYPE_RSTBPDU = 2
 146 DEFAULT_BRIDGE_PRIORITY = 32768
 147 DEFAULT_PORT_PRIORITY = 128
 148 PORT_PATH_COST_100KB = 200000000
 149 PORT_PATH_COST_1MB = 20000000
 150 PORT_PATH_COST_10MB = 2000000
 151 PORT_PATH_COST_100MB = 200000
 152 PORT_PATH_COST_1GB = 20000
 153 PORT_PATH_COST_10GB = 2000
 154 PORT_PATH_COST_100GB = 200
 155 PORT_PATH_COST_1TB = 20
 156 PORT_PATH_COST_10TB = 2
 157 DEFAULT_MAX_AGE = 20
 158 DEFAULT_HELLO_TIME = 2
 159 DEFAULT_FORWARD_DELAY = 15
 160 VERSION_1_LENGTH = 0
 161
 162
 163 class bpdu(packet_base.PacketBase):
 164     """Bridge Protocol Data Unit(BPDU) header encoder/decoder base class.
 165     """
 166     _PACK_STR = '!HBB'
 167     _PACK_LEN = struct.calcsize(_PACK_STR)
 168     _BPDU_TYPES = {}
 169
 170     _MIN_LEN = _PACK_LEN
 171
 172     @staticmethod
 173     def register_bpdu_type(sub_cls):
 174         bpdu._BPDU_TYPES.setdefault(sub_cls.VERSION_ID, {})
 175         bpdu._BPDU_TYPES[sub_cls.VERSION_ID][sub_cls.BPDU_TYPE] = sub_cls
 176         return sub_cls
 177
 178     def __init__(self):
 179         super(bpdu, self).__init__()
 180
 181         assert hasattr(self, 'VERSION_ID')
 182         assert hasattr(self, 'BPDU_TYPE')
 183
 184         self._protocol_id = PROTOCOL_IDENTIFIER
 185         self._version_id = self.VERSION_ID
 186         self._bpdu_type = self.BPDU_TYPE
 187
 188         if hasattr(self, 'check_parameters'):
 189             self.check_parameters()
 190
 191     @classmethod
 192     def parser(cls, buf):
 193         assert len(buf) >= cls._PACK_LEN
 194         (protocol_id, version_id,
 195          bpdu_type) = struct.unpack_from(cls._PACK_STR, buf)
 196         assert protocol_id == PROTOCOL_IDENTIFIER
 197
 198         if (version_id in cls._BPDU_TYPES
 199                 and bpdu_type in cls._BPDU_TYPES[version_id]):
 200             bpdu_cls = cls._BPDU_TYPES[version_id][bpdu_type]
 201             assert len(buf[cls._PACK_LEN:]) >= bpdu_cls.PACK_LEN
 202             return bpdu_cls.parser(buf[cls._PACK_LEN:])
 203         else:
 204             # Unknown bpdu version/type.
 205             return buf, None, None
 206
 207     def serialize(self, payload, prev):
 208         return struct.pack(bpdu._PACK_STR, self._protocol_id,
 209                            self._version_id, self._bpdu_type)
 210
 211
 212 @bpdu.register_bpdu_type
 213 class ConfigurationBPDUs(bpdu):
 214     """Configuration BPDUs(IEEE 802.1D) header encoder/decoder class.
 215
 216     An instance has the following attributes at least.
 217     Most of them are same to the on-wire counterparts but in host byte
 218     order.
 219     __init__ takes the corresponding args in this order.
 220
 221     ========================== ===============================================
 222     Attribute                  Description
 223     ========================== ===============================================
 224     flags                      | Bit 1: Topology Change flag
 225                                | Bits 2 through 7: unused and take the value 0
 226                                | Bit 8: Topology Change Acknowledgment flag
 227     root_priority              Root Identifier priority \
 228                                set 0-61440 in steps of 4096
 229     root_system_id_extension   Root Identifier system ID extension
 230     root_mac_address           Root Identifier MAC address
 231     root_path_cost             Root Path Cost
 232     bridge_priority            Bridge Identifier priority \
 233                                set 0-61440 in steps of 4096
 234     bridge_system_id_extension Bridge Identifier system ID extension
 235     bridge_mac_address         Bridge Identifier MAC address
 236     port_priority              Port Identifier priority \
 237                                set 0-240 in steps of 16
 238     port_number                Port Identifier number
 239     message_age                Message Age timer value
 240     max_age                    Max Age timer value
 241     hello_time                 Hello Time timer value
 242     forward_delay              Forward Delay timer value
 243     ========================== ===============================================
 244     """
 245
 246     VERSION_ID = PROTOCOLVERSION_ID_BPDU
 247     BPDU_TYPE = TYPE_CONFIG_BPDU
 248     _PACK_STR = '!BQIQHHHHH'
 249     PACK_LEN = struct.calcsize(_PACK_STR)
 250     _TYPE = {
 251         'ascii': [
 252             'root_mac_address', "bridge_mac_address"
 253         ]
 254     }
 255
 256     _BRIDGE_PRIORITY_STEP = 4096
 257     _PORT_PRIORITY_STEP = 16
 258     _TIMER_STEP = float(1) / 256
 259
 260     def __init__(self, flags=0, root_priority=DEFAULT_BRIDGE_PRIORITY,
 261                  root_system_id_extension=0,
 262                  root_mac_address='00:00:00:00:00:00',
 263                  root_path_cost=0, bridge_priority=DEFAULT_BRIDGE_PRIORITY,
 264                  bridge_system_id_extension=0,
 265                  bridge_mac_address='00:00:00:00:00:00',
 266                  port_priority=DEFAULT_PORT_PRIORITY, port_number=0,
 267                  message_age=0, max_age=DEFAULT_MAX_AGE,
 268                  hello_time=DEFAULT_HELLO_TIME,
 269                  forward_delay=DEFAULT_FORWARD_DELAY):
 270         self.flags = flags
 271         self.root_priority = root_priority
 272         self.root_system_id_extension = root_system_id_extension
 273         self.root_mac_address = root_mac_address
 274         self.root_path_cost = root_path_cost
 275         self.bridge_priority = bridge_priority
 276         self.bridge_system_id_extension = bridge_system_id_extension
 277         self.bridge_mac_address = bridge_mac_address
 278         self.port_priority = port_priority
 279         self.port_number = port_number
 280         self.message_age = message_age
 281         self.max_age = max_age
 282         self.hello_time = hello_time
 283         self.forward_delay = forward_delay
 284
 285         super(ConfigurationBPDUs, self).__init__()
 286
 287     def check_parameters(self):
 288         assert (self.flags >> 1 & 0b111111) == 0
 289         assert self.root_priority % self._BRIDGE_PRIORITY_STEP == 0
 290         assert self.bridge_priority % self._BRIDGE_PRIORITY_STEP == 0
 291         assert self.port_priority % self._PORT_PRIORITY_STEP == 0
 292         assert self.message_age % self._TIMER_STEP == 0
 293         assert self.max_age % self._TIMER_STEP == 0
 294         assert self.hello_time % self._TIMER_STEP == 0
 295         assert self.forward_delay % self._TIMER_STEP == 0
 296
 297     @classmethod
 298     def parser(cls, buf):
 299         (flags, root_id, root_path_cost, bridge_id,
 300          port_id, message_age, max_age, hello_time,
 301          forward_delay) = struct.unpack_from(ConfigurationBPDUs._PACK_STR, buf)
 302
 303         (root_priority,
 304          root_system_id_extension,
 305          root_mac_address) = cls._decode_bridge_id(root_id)
 306         (bridge_priority,
 307          bridge_system_id_extension,
 308          bridge_mac_address) = cls._decode_bridge_id(bridge_id)
 309         (port_priority,
 310          port_number) = cls._decode_port_id(port_id)
 311
 312         return (cls(flags, root_priority, root_system_id_extension,
 313                     root_mac_address, root_path_cost,
 314                     bridge_priority, bridge_system_id_extension,
 315                     bridge_mac_address, port_priority, port_number,
 316                     cls._decode_timer(message_age),
 317                     cls._decode_timer(max_age),
 318                     cls._decode_timer(hello_time),
 319                     cls._decode_timer(forward_delay)),
 320                 None, buf[ConfigurationBPDUs.PACK_LEN:])
 321
 322     def serialize(self, payload, prev):
 323         base = super(ConfigurationBPDUs, self).serialize(payload, prev)
 324
 325         root_id = self.encode_bridge_id(self.root_priority,
 326                                         self.root_system_id_extension,
 327                                         self.root_mac_address)
 328         bridge_id = self.encode_bridge_id(self.bridge_priority,
 329                                           self.bridge_system_id_extension,
 330                                           self.bridge_mac_address)
 331         port_id = self.encode_port_id(self.port_priority,
 332                                       self.port_number)
 333         sub = struct.pack(ConfigurationBPDUs._PACK_STR,
 334                           self.flags,
 335                           root_id,
 336                           self.root_path_cost,
 337                           bridge_id,
 338                           port_id,
 339                           self._encode_timer(self.message_age),
 340                           self._encode_timer(self.max_age),
 341                           self._encode_timer(self.hello_time),
 342                           self._encode_timer(self.forward_delay))
 343
 344         return base + sub
 345
 346     @staticmethod
 347     def _decode_bridge_id(bridge_id):
 348         priority = (bridge_id >> 48) & 0xf000
 349         system_id_extension = (bridge_id >> 48) & 0xfff
 350         mac_addr = bridge_id & 0xffffffffffff
 351
 352         mac_addr_list = [format((mac_addr >> (8 * i)) & 0xff, '02x')
 353                          for i in range(0, 6)]
 354         mac_addr_list.reverse()
 355         mac_address_bin = binascii.a2b_hex(''.join(mac_addr_list))
 356         mac_address = addrconv.mac.bin_to_text(mac_address_bin)
 357
 358         return priority, system_id_extension, mac_address
 359
 360     @staticmethod
 361     def encode_bridge_id(priority, system_id_extension, mac_address):
 362         mac_addr = int(binascii.hexlify(addrconv.mac.text_to_bin(mac_address)),
 363                        16)
 364         return ((priority + system_id_extension) << 48) + mac_addr
 365
 366     @staticmethod
 367     def _decode_port_id(port_id):
 368         priority = port_id >> 8 & 0xf0
 369         port_number = port_id & 0xfff
 370         return priority, port_number
 371
 372     @staticmethod
 373     def encode_port_id(priority, port_number):
 374         return (priority << 8) + port_number
 375
 376     @staticmethod
 377     def _decode_timer(timer):
 378         return timer / float(0x100)
 379
 380     @staticmethod
 381     def _encode_timer(timer):
 382         return int(timer) * 0x100
 383
 384
 385 @bpdu.register_bpdu_type
 386 class TopologyChangeNotificationBPDUs(bpdu):
 387     """Topology Change Notification BPDUs(IEEE 802.1D)
 388     header encoder/decoder class.
 389     """
 390
 391     VERSION_ID = PROTOCOLVERSION_ID_BPDU
 392     BPDU_TYPE = TYPE_TOPOLOGY_CHANGE_BPDU
 393     _PACK_STR = ''
 394     PACK_LEN = struct.calcsize(_PACK_STR)
 395
 396     def __init__(self):
 397         super(TopologyChangeNotificationBPDUs, self).__init__()
 398
 399     @classmethod
 400     def parser(cls, buf):
 401         return cls(), None, buf[bpdu._PACK_LEN:]
 402
 403
 404 @bpdu.register_bpdu_type
 405 class RstBPDUs(ConfigurationBPDUs):
 406     """Rapid Spanning Tree BPDUs(RST BPDUs, IEEE 802.1D)
 407     header encoder/decoder class.
 408
 409     An instance has the following attributes at least.
 410     Most of them are same to the on-wire counterparts but in host byte
 411     order.
 412     __init__ takes the corresponding args in this order.
 413
 414     ========================== ===========================================
 415     Attribute                  Description
 416     ========================== ===========================================
 417     flags                      | Bit 1: Topology Change flag
 418                                | Bit 2: Proposal flag
 419                                | Bits 3 and 4: Port Role
 420                                | Bit 5: Learning flag
 421                                | Bit 6: Forwarding flag
 422                                | Bit 7: Agreement flag
 423                                | Bit 8: Topology Change Acknowledgment flag
 424     root_priority              Root Identifier priority \
 425                                set 0-61440 in steps of 4096
 426     root_system_id_extension   Root Identifier system ID extension
 427     root_mac_address           Root Identifier MAC address
 428     root_path_cost             Root Path Cost
 429     bridge_priority            Bridge Identifier priority \
 430                                set 0-61440 in steps of 4096
 431     bridge_system_id_extension Bridge Identifier system ID extension
 432     bridge_mac_address         Bridge Identifier MAC address
 433     port_priority              Port Identifier priority \
 434                                set 0-240 in steps of 16
 435     port_number                Port Identifier number
 436     message_age                Message Age timer value
 437     max_age                    Max Age timer value
 438     hello_time                 Hello Time timer value
 439     forward_delay              Forward Delay timer value
 440     ========================== ===========================================
 441     """
 442
 443     VERSION_ID = PROTOCOLVERSION_ID_RSTBPDU
 444     BPDU_TYPE = TYPE_RSTBPDU
 445     _PACK_STR = '!B'
 446     PACK_LEN = struct.calcsize(_PACK_STR)
 447
 448     def __init__(self, flags=0, root_priority=DEFAULT_BRIDGE_PRIORITY,
 449                  root_system_id_extension=0,
 450                  root_mac_address='00:00:00:00:00:00',
 451                  root_path_cost=0, bridge_priority=DEFAULT_BRIDGE_PRIORITY,
 452                  bridge_system_id_extension=0,
 453                  bridge_mac_address='00:00:00:00:00:00',
 454                  port_priority=DEFAULT_PORT_PRIORITY, port_number=0,
 455                  message_age=0, max_age=DEFAULT_MAX_AGE,
 456                  hello_time=DEFAULT_HELLO_TIME,
 457                  forward_delay=DEFAULT_FORWARD_DELAY):
 458         self._version_1_length = VERSION_1_LENGTH
 459
 460         super(RstBPDUs, self).__init__(flags, root_priority,
 461                                        root_system_id_extension,
 462                                        root_mac_address, root_path_cost,
 463                                        bridge_priority,
 464                                        bridge_system_id_extension,
 465                                        bridge_mac_address,
 466                                        port_priority, port_number,
 467                                        message_age, max_age,
 468                                        hello_time, forward_delay)
 469
 470     def check_parameters(self):
 471         assert self.root_priority % self._BRIDGE_PRIORITY_STEP == 0
 472         assert self.bridge_priority % self._BRIDGE_PRIORITY_STEP == 0
 473         assert self.port_priority % self._PORT_PRIORITY_STEP == 0
 474         assert self.message_age % self._TIMER_STEP == 0
 475         assert self.max_age % self._TIMER_STEP == 0
 476         assert self.hello_time % self._TIMER_STEP == 0
 477         assert self.forward_delay % self._TIMER_STEP == 0
 478
 479     @classmethod
 480     def parser(cls, buf):
 481         get_cls, next_type, buf = super(RstBPDUs, cls).parser(buf)
 482
 483         (version_1_length,) = struct.unpack_from(RstBPDUs._PACK_STR, buf)
 484         assert version_1_length == VERSION_1_LENGTH
 485
 486         return get_cls, next_type, buf[RstBPDUs.PACK_LEN:]
 487
 488     def serialize(self, payload, prev):
 489         base = super(RstBPDUs, self).serialize(payload, prev)
 490         sub = struct.pack(RstBPDUs._PACK_STR, self._version_1_length)
 491         return base + sub