From a7499bb1b10a86e15e2823d1b5ff85e1841f932b Mon Sep 17 00:00:00 2001
From: "watanabe.fumitaka" <watanabe.fumitaka@nttcom.co.jp>
Date: Tue, 23 Jul 2013 14:02:21 +0900
Subject: [PATCH] lib/packet/llc
Signed-off-by: WATANABE Fumitaka <watanabe.fumitaka@nttcom.co.jp>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
---
ryu/lib/packet/llc.py | 315 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 315 insertions(+)
create mode 100644 ryu/lib/packet/llc.py
diff --git a/ryu/lib/packet/llc.py b/ryu/lib/packet/llc.py
new file mode 100644
index 00000000..5af62ea4
--- /dev/null
+++ b/ryu/lib/packet/llc.py
@@ -0,0 +1,315 @@
+# 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.
+
+
+"""
+Logical Link Control(LLC, IEEE 802.2) parser/serializer
+http://standards.ieee.org/getieee802/download/802.2-1998.pdf
+
+
+LLC format
+
+ +-----------------+--------------+
+ | DSAP address | 8 bits |
+ +-----------------+--------------+
+ | SSAP address | 8 bits |
+ +-----------------+--------------+
+ | Control | 8 or 16 bits |
+ +-----------------+--------------+
+
+
+DSAP address field
+
+ LSB
+ +-----+---+---+---+---+---+---+---+
+ | I/G | D | D | D | D | D | D | D |
+ +-----+---+---+---+---+---+---+---+
+ I/G bit = 0 : Individual DSAP
+ I/G bit = 1 : Group DSA
+ D : DSAP address
+
+SSAP address field
+
+ LSB
+ +-----+---+---+---+---+---+---+---+
+ | C/R | S | S | S | S | S | S | S |
+ +-----+---+---+---+---+---+---+---+
+ C/R bit = 0 : Command
+ C/R bit = 1 : Response
+ S : SSAP address
+
+
+Control field
+
+ Information transfer
+ command/response
+ (I-format PDU)
+ 1 2 3 4 5 6 7 8 9 10-16
+ +---+---+---+---+---+---+---+---+-----+------+
+ | 0 | N(S) | P/F | N(R) |
+ +---+---+---+---+---+---+---+---+-----+------+
+
+ Supervisory
+ commands/responses
+ (S-format PDUs)
+ 1 2 3 4 5 6 7 8 9 10-16
+ +---+---+---+---+---+---+---+---+-----+------+
+ | 1 0 | S S | 0 0 0 0 | P/F | N(R) |
+ +---+---+---+---+---+---+---+---+-----+------+
+
+ Unnumbered
+ commands/responses
+ (U-format PDUs)
+ 1 2 3 4 5 6 7 8
+ +---+---+----+---+-----+---+----+---+
+ | 1 1 | M1 M1 | P/F | M2 M2 M2 |
+ +---+---+----+---+-----+---+----+---+
+
+ N(S) : sender send sequence number (Bit 2=lower-order-bit)
+ N(R) : sender receive sequence number (Bit 10=lower-order-bit)
+ S : supervisory function bit
+ M1/M2: modifier function bit
+ P/F : poll bit - command LLC PDUs
+ final bit - response LLC PDUs
+
+"""
+
+
+import struct
+from . import bpdu
+from . import packet_base
+
+
+SAP_BDPU = 0x42
+
+
+class llc(packet_base.PacketBase):
+ """LLC(IEEE 802.2) 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
+ =============== ===============================================
+ dsap_addr Destination service access point address field \
+ includes I/G bit at least significant bit.
+ ssap_addr Source service access point address field \
+ includes C/R bit at least significant bit.
+ control Control field \
+ [16 bits for formats that include sequence \
+ numbering, and 8 bits for formats that do not]. \
+ Either ryu.lib.packet.llc.ControlFormatI or \
+ ryu.lib.packet.llc.ControlFormatS or \
+ ryu.lib.packet.llc.ControlFormatU object.
+ =============== ===============================================
+ """
+
+ _PACK_STR = '!BB'
+ _PACK_LEN = struct.calcsize(_PACK_STR)
+ _CTR_TYPES = {}
+ _CTR_PACK_STR = '!2xB'
+
+ @staticmethod
+ def register_control_type(register_cls):
+ llc._CTR_TYPES[register_cls.TYPE] = register_cls
+ return register_cls
+
+ def __init__(self, dsap_addr, ssap_addr, control):
+ super(llc, self).__init__()
+
+ assert getattr(control, 'TYPE', None) in self._CTR_TYPES
+
+ self.dsap_addr = dsap_addr
+ self.ssap_addr = ssap_addr
+ self.control = control
+
+ @classmethod
+ def parser(cls, buf):
+ assert len(buf) >= cls._PACK_LEN
+ (dsap_addr, ssap_addr) = struct.unpack_from(cls._PACK_STR, buf)
+
+ (control,) = struct.unpack_from(cls._CTR_PACK_STR, buf)
+ ctrl = cls._get_control(control)
+ control, information = ctrl.parser(buf[cls._PACK_LEN:])
+
+ return (cls(dsap_addr, ssap_addr, control),
+ cls.get_packet_type(dsap_addr), information)
+
+ def serialize(self, payload, prev):
+ addr = struct.pack(self._PACK_STR, self.dsap_addr, self.ssap_addr)
+ control = self.control.serialize()
+ return addr + control
+
+ @classmethod
+ def _get_control(cls, buf):
+ key = buf & 0b1 if buf & 0b1 == ControlFormatI.TYPE else buf & 0b11
+ return cls._CTR_TYPES[key]
+
+
+@llc.register_control_type
+class ControlFormatI(object):
+ """LLC sub encoder/decoder class for control I-format field.
+
+ 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
+ ======================== ===============================
+ send_sequence_number sender send sequence number
+ pf_bit poll/final bit
+ receive_sequence_number sender receive sequence number
+ ======================== ===============================
+ """
+ TYPE = 0b0
+ _PACK_STR = '!H'
+ _PACK_LEN = struct.calcsize(_PACK_STR)
+
+ def __init__(self, send_sequence_number=0, pf_bit=0,
+ receive_sequence_number=0):
+ super(ControlFormatI, self).__init__()
+ self.send_sequence_number = send_sequence_number
+ self.pf_bit = pf_bit
+ self.receive_sequence_number = receive_sequence_number
+
+ @classmethod
+ def parser(cls, buf):
+ assert len(buf) >= cls._PACK_LEN
+ (control,) = struct.unpack_from(cls._PACK_STR, buf)
+ assert (control >> 8) & 0b1 == cls.TYPE
+
+ send_sequence_number = (control >> 9) & 0b1111111
+ pf_bit = (control >> 8) & 0b1
+ receive_sequence_number = (control >> 1) & 0b1111111
+
+ return cls(send_sequence_number, pf_bit,
+ receive_sequence_number), buf[cls._PACK_LEN:]
+
+ def serialize(self):
+ control = (self.send_sequence_number << 9 |
+ self.TYPE << 8 |
+ self.receive_sequence_number << 1 |
+ self.pf_bit)
+ return struct.pack(self._PACK_STR, control)
+
+
+@llc.register_control_type
+class ControlFormatS(object):
+ """LLC sub encoder/decoder class for control S-format field.
+
+ 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
+ ======================== ===============================
+ supervisory_function supervisory function bit
+ pf_bit poll/final bit
+ receive_sequence_number sender receive sequence number
+ ======================== ===============================
+ """
+
+ TYPE = 0b01
+ _PACK_STR = '!H'
+ _PACK_LEN = struct.calcsize(_PACK_STR)
+
+ def __init__(self, supervisory_function=0, pf_bit=0,
+ receive_sequence_number=0):
+ super(ControlFormatS, self).__init__()
+ self.supervisory_function = supervisory_function
+ self.pf_bit = pf_bit
+ self.receive_sequence_number = receive_sequence_number
+
+ @classmethod
+ def parser(cls, buf):
+ assert len(buf) >= cls._PACK_LEN
+ (control,) = struct.unpack_from(cls._PACK_STR, buf)
+
+ assert (control >> 8) & 0b11 == cls.TYPE
+ assert (control >> 12) & 0b1111 == 0
+
+ supervisory_function = (control >> 10) & 0b11
+ pf_bit = (control >> 8) & 0b1
+ receive_sequence_number = (control >> 1) & 0b1111111
+
+ return cls(supervisory_function, pf_bit,
+ receive_sequence_number), buf[cls._PACK_LEN:]
+
+ def serialize(self):
+ control = (self.supervisory_function << 10 |
+ self.TYPE << 8 |
+ self.receive_sequence_number << 1 |
+ self.pf_bit)
+ return struct.pack(self._PACK_STR, control)
+
+
+@llc.register_control_type
+class ControlFormatU(object):
+ """LLC sub encoder/decoder class for control U-format field.
+
+ 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
+ ======================== ===============================
+ modifier_function1 modifier function bit
+ pf_bit poll/final bit
+ modifier_function2 modifier function bit
+ ======================== ===============================
+ """
+
+ TYPE = 0b11
+ _PACK_STR = '!B'
+ _PACK_LEN = struct.calcsize(_PACK_STR)
+
+ def __init__(self, modifier_function1=0, pf_bit=0, modifier_function2=0):
+ super(ControlFormatU, self).__init__()
+ self.modifier_function1 = modifier_function1
+ self.pf_bit = pf_bit
+ self.modifier_function2 = modifier_function2
+
+ @classmethod
+ def parser(cls, buf):
+ assert len(buf) >= cls._PACK_LEN
+ (control,) = struct.unpack_from(cls._PACK_STR, buf)
+
+ assert control & 0b11 == cls.TYPE
+
+ modifier_function1 = (control >> 2) & 0b11
+ pf_bit = (control >> 4) & 0b1
+ modifier_function2 = (control >> 5) & 0b111
+
+ return cls(modifier_function1, pf_bit,
+ modifier_function2), buf[cls._PACK_LEN:]
+
+ def serialize(self):
+ control = (self.modifier_function2 << 5 |
+ self.pf_bit << 4 |
+ self.modifier_function1 << 2 |
+ self.TYPE)
+ return struct.pack(self._PACK_STR, control)
+
+
+llc.register_packet_type(bpdu.bpdu, SAP_BDPU)