Signed-off-by: YAMAMOTO Takashi <[email protected]> --- ryu/lib/packet/bgp.py | 519 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 519 insertions(+) create mode 100644 ryu/lib/packet/bgp.py
diff --git a/ryu/lib/packet/bgp.py b/ryu/lib/packet/bgp.py new file mode 100644 index 0000000..a6d5f4d --- /dev/null +++ b/ryu/lib/packet/bgp.py @@ -0,0 +1,519 @@ +# Copyright (C) 2013 Nippon Telegraph and Telephone Corporation. +# Copyright (C) 2013 YAMAMOTO Takashi <yamamoto at valinux co jp> +# +# 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. + +""" +RFC 4271 BGP-4 +""" + +# todo +# - streaming parser +# - notify data +# - notify subcode constants +# - RFC 1997 BGP Communities Attribute +# - RFC 2918 Route Refresh Capability for BGP-4 +# - RFC 3107 Carrying Label Information in BGP-4 +# - RFC 4360 BGP Extended Communities Attribute +# - RFC 4364 BGP/MPLS IP Virtual Private Networks (VPNs) +# - RFC 4486 Subcodes for BGP Cease Notification Message +# - RFC 4760 Multiprotocol Extensions for BGP-4 + +import struct + +from ryu.ofproto.ofproto_parser import msg_pack_into +from ryu.lib.stringify import StringifyMixin +from ryu.lib.packet import packet_base +from ryu.lib import addrconv + + +BGP_MSG_OPEN = 1 +BGP_MSG_UPDATE = 2 +BGP_MSG_NOTIFICATION = 3 +BGP_MSG_KEEPALIVE = 4 +BGP_MSG_ROUTE_REFRESH = 5 # RFC 2918 + +# RFC 4271 4.5. +BGP_ERROR_MESSAGE_HEADER_ERROR = 1 +BGP_ERROR_OPEN_MESSAGE_ERROR = 2 +BGP_ERROR_UPDATE_MESSAGE_ERROR = 3 +BGP_ERROR_HOLD_TIMER_EXPIRED = 4 +BGP_ERROR_FSM_ERROR = 5 +BGP_ERROR_CEASE = 6 + +_VERSION = 4 +_MARKER = 16 * '\xff' + +BGP_OPT_CAPABILITY = 2 # RFC 3392 + +BGP_ATTR_FLAG_OPTIONAL = 1 << 7 +BGP_ATTR_FLAG_TRANSITIVE = 1 << 6 +BGP_ATTR_FLAG_PARTIAL = 1 << 5 +BGP_ATTR_FLAG_EXTENDED_LENGTH = 1 << 4 + +BGP_ATTR_TYPE_ORIGIN = 1 +BGP_ATTR_TYPE_AS_PATH = 2 +BGP_ATTR_TYPE_NEXT_HOP = 3 +BGP_ATTR_TYPE_MULTI_EXIT_DISC = 4 +BGP_ATTR_TYPE_LOCAL_PREF = 5 +BGP_ATTR_TYPE_ATOMIC_AGGREGATE = 6 +BGP_ATTR_TYPE_AGGREGATOR = 7 +BGP_ATTR_TYPE_MP_REACH_NLRI = 14 # RFC 4760 +BGP_ATTR_TYPE_MP_UNREACH_NLRI = 15 # RFC 4760 + + +def pad(bin, len_): + assert len(bin) <= len_ + return bin + (len_ - len(bin)) * '\0' + + +class _IPAddrPrefix(StringifyMixin): + _PACK_STR = '!B' # length + + def __init__(self, length, ip_addr): + self.length = length + self.ip_addr = ip_addr + + @classmethod + def parser(cls, buf): + (length, ) = struct.unpack_from(cls._PACK_STR, buffer(buf)) + rest = buf[struct.calcsize(cls._PACK_STR):] + byte_length = (length + 7) / 8 + ip_addr = addrconv.ipv4.bin_to_text(pad(rest[:byte_length], 4)) + rest = rest[byte_length:] + return cls(length=length, ip_addr=ip_addr), rest + + def serialize(self): + # fixup + byte_length = (self.length + 7) / 8 + bin_ip_addr = addrconv.ipv4.text_to_bin(self.ip_addr) + if (self.length % 8) == 0: + bin_ip_addr = bin_ip_addr[:byte_length] + else: + # clear trailing bits in the last octet. + # rfc doesn't require this. + mask = 0xff00 >> (self.length % 8) + last_byte = chr(ord(bin_ip_addr[byte_length - 1]) & mask) + bin_ip_addr = bin_ip_addr[:byte_length - 1] + last_byte + self.ip_addr = addrconv.ipv4.bin_to_text(pad(bin_ip_addr, 4)) + + buf = bytearray() + msg_pack_into(self._PACK_STR, buf, 0, self.length) + return buf + bytes(bin_ip_addr) + + +class BGPOptParam(StringifyMixin): + _PACK_STR = '!BB' # type, length + + def __init__(self, type_, value, length=None): + self.type = type_ + self.length = length + self.value = value + + @classmethod + def parser(cls, buf): + (type_, length) = struct.unpack_from(cls._PACK_STR, buffer(buf)) + rest = buf[struct.calcsize(cls._PACK_STR):] + value = bytes(rest[:length]) + rest = rest[length:] + return cls(type_=type_, length=length, value=value), rest + + def serialize(self): + # fixup + self.length = len(self.value) + + buf = bytearray() + msg_pack_into(self._PACK_STR, buf, 0, self.type, self.length) + return buf + bytes(self.value) + + +class BGPWithdrawnRoute(_IPAddrPrefix): + pass + + +class BGPPathAttribute(StringifyMixin): + _PACK_STR = '!BB' # flags, type + _PACK_STR_LEN = '!B' # length + _PACK_STR_EXT_LEN = '!H' # length w/ BGP_ATTR_FLAG_EXTENDED_LENGTH + + def __init__(self, flags, type_, value, length=None): + self.flags = flags + self.type = type_ + self.length = length + self.value = value + + @classmethod + def parser(cls, buf): + (flags, type_) = struct.unpack_from(cls._PACK_STR, buffer(buf)) + rest = buf[struct.calcsize(cls._PACK_STR):] + if (flags & BGP_ATTR_FLAG_EXTENDED_LENGTH) != 0: + len_pack_str = cls._PACK_STR_EXT_LEN + else: + len_pack_str = cls._PACK_STR_LEN + (length,) = struct.unpack_from(len_pack_str, buffer(rest)) + rest = rest[struct.calcsize(len_pack_str):] + value = bytes(rest[:length]) + rest = rest[length:] + return cls(flags=flags, type_=type_, length=length, value=value), rest + + def serialize(self): + # fixup + self.length = len(self.value) + if self.length > 255: + self.flags |= BGP_ATTR_FLAG_EXTENDED_LENGTH + len_pack_str = self._PACK_STR_EXT_LEN + else: + self.flags &= ~BGP_ATTR_FLAG_EXTENDED_LENGTH + len_pack_str = self._PACK_STR_LEN + + buf = bytearray() + msg_pack_into(self._PACK_STR, buf, 0, self.flags, self.type) + msg_pack_into(len_pack_str, buf, len(buf), self.length) + return buf + bytes(self.value) + + +class BGPNLRI(_IPAddrPrefix): + pass + + +class BGPMessage(packet_base.PacketBase): + """Base class for BGP-4 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 correspondig args in this order. + + ========================== =============================================== + Attribute Description + ========================== =============================================== + marker Marker field. Ignored when encoding. + len Length field. Ignored when encoding. + type Type field. one of BGP\_MSG\_ constants. + ========================== =============================================== + """ + + _HDR_PACK_STR = '!16sHB' # marker, len, type + _HDR_LEN = struct.calcsize(_HDR_PACK_STR) + _TYPES = {} + + @classmethod + def register_type(cls, type_): + def _register_type(subcls): + cls._TYPES[type_] = subcls + return subcls + return _register_type + + def __init__(self, type_, len_=None, marker=None): + if marker is None: + self.marker = _MARKER + else: + self.marker = marker + self.len = len_ + self.type = type_ + + @classmethod + def parser(cls, buf): + (marker, len_, type_) = struct.unpack_from(cls._HDR_PACK_STR, + buffer(buf)) + subcls = cls._TYPES[type_] + kwargs = subcls.parser(buf[cls._HDR_LEN:]) + return subcls(marker=marker, len_=len_, type_=type_, **kwargs) + + def serialize(self): + # fixup + self.marker = _MARKER + tail = self.serialize_tail() + self.len = self._HDR_LEN + len(tail) + + hdr = bytearray(struct.pack(self._HDR_PACK_STR, self.marker, + self.len, self.type)) + return hdr + tail + + def __len__(self): + # XXX destructive + buf = self.serialize() + return len(buf) + + [email protected]_type(BGP_MSG_OPEN) +class BGPOpen(BGPMessage): + """BGP-4 OPEN Message 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 + ========================== =============================================== + marker Marker field. Ignored when encoding. + len Length field. Ignored when encoding. + type Type field. The default is BGP_MSG_OPEN. + version Version field. The default is 4. + my_as My Autonomous System field. 2 octet unsigned + integer. + hold_time Hold Time field. 2 octet unsigned integer. + The default is 0. + bgp_identifier BGP Identifier field. An IPv4 address. + For example, '192.0.2.1' + opt_param_len Optional Parameters Length field. + Ignored when encoding. + opt_param Optional Parameters field. A list of + BGPOptParam instances. The default is []. + ========================== =============================================== + """ + + _PACK_STR = '!BHH4sB' + _MIN_LEN = BGPMessage._HDR_LEN + struct.calcsize(_PACK_STR) + + def __init__(self, my_as, bgp_identifier, type_=BGP_MSG_OPEN, + opt_param_len=0, opt_param=[], + version=_VERSION, hold_time=0, len_=None, marker=None): + super(BGPOpen, self).__init__(marker=marker, len_=len_, type_=type_) + self.version = version + self.my_as = my_as + self.bgp_identifier = bgp_identifier + self.hold_time = hold_time + self.opt_param_len = opt_param_len + self.opt_param = opt_param + + @classmethod + def parser(cls, buf): + (version, my_as, hold_time, + bgp_identifier, opt_param_len) = struct.unpack_from(cls._PACK_STR, + buffer(buf)) + rest = buf[struct.calcsize(cls._PACK_STR):] + binopts = rest[:opt_param_len] + opt_param = [] + while binopts: + opt, binopts = BGPOptParam.parser(binopts) + opt_param.append(opt) + return { + "version": version, + "my_as": my_as, + "hold_time": hold_time, + "bgp_identifier": addrconv.ipv4.bin_to_text(bgp_identifier), + "opt_param_len": opt_param_len, + "opt_param": opt_param, + } + + def serialize_tail(self): + # fixup + self.version = _VERSION + binopts = bytearray() + for opt in self.opt_param: + binopts += opt.serialize() + self.opt_param_len = len(binopts) + + msg = bytearray(struct.pack(self._PACK_STR, + self.version, + self.my_as, + self.hold_time, + addrconv.ipv4.text_to_bin( + self.bgp_identifier), + self.opt_param_len)) + msg += binopts + return msg + + [email protected]_type(BGP_MSG_UPDATE) +class BGPUpdate(BGPMessage): + """BGP-4 UPDATE Message 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 + ========================== =============================================== + marker Marker field. Ignored when encoding. + len Length field. Ignored when encoding. + type Type field. The default is BGP_MSG_UPDATE. + withdrawn_routes_len Withdrawn Routes Length field. + Ignored when encoding. + withdrawn_routes Withdrawn Routes field. A list of + BGPWithdrawnRoute instances. + The default is []. + total_path_attribute_len Total Path Attribute Length field. + Ignored when encoding. + path_attributes Path Attributes field. A list of + BGPPathAttribute instances. + The default is []. + nlri Network Layer Reachability Information field. + A list of BGPNLRI instances. + The default is []. + ========================== =============================================== + """ + + def __init__(self, type_=BGP_MSG_UPDATE, + withdrawn_routes_len=None, + withdrawn_routes=[], + total_path_attribute_len=None, + path_attributes=[], + nlri=[], + len_=None, marker=None): + super(BGPUpdate, self).__init__(marker=marker, len_=len_, type_=type_) + self.withdrawn_routes_len = withdrawn_routes_len + self.withdrawn_routes = withdrawn_routes + self.total_path_attribute_len = total_path_attribute_len + self.path_attributes = path_attributes + self.nlri = nlri + + @classmethod + def parser(cls, buf): + offset = 0 + (withdrawn_routes_len,) = struct.unpack_from('!H', buffer(buf), offset) + binroutes = buffer(buf[offset + 2: + offset + 2 + withdrawn_routes_len]) + offset += 2 + withdrawn_routes_len + (total_path_attribute_len,) = struct.unpack_from('!H', buffer(buf), + offset) + binpathattrs = buffer(buf[offset + 2: + offset + 2 + total_path_attribute_len]) + binnlri = buffer(buf[offset + 2 + total_path_attribute_len:]) + withdrawn_routes = [] + while binroutes: + r, binroutes = BGPWithdrawnRoute.parser(binroutes) + withdrawn_routes.append(r) + path_attributes = [] + while binpathattrs: + pa, binpathattrs = BGPPathAttribute.parser(binpathattrs) + path_attributes.append(pa) + offset += 2 + total_path_attribute_len + nlri = [] + while binnlri: + n, binnlri = BGPNLRI.parser(binnlri) + nlri.append(n) + return { + "withdrawn_routes_len": withdrawn_routes_len, + "withdrawn_routes": withdrawn_routes, + "total_path_attribute_len": total_path_attribute_len, + "path_attributes": path_attributes, + "nlri": nlri, + } + + def serialize_tail(self): + # fixup + binroutes = bytearray() + for r in self.withdrawn_routes: + binroutes += r.serialize() + self.withdrawn_routes_len = len(binroutes) + binpathattrs = bytearray() + for pa in self.path_attributes: + binpathattrs += pa.serialize() + self.total_path_attribute_len = len(binpathattrs) + binnlri = bytearray() + for n in self.nlri: + binnlri += n.serialize() + + msg = bytearray() + offset = 0 + msg_pack_into('!H', msg, offset, self.withdrawn_routes_len) + msg += binroutes + offset += 2 + self.withdrawn_routes_len + msg_pack_into('!H', msg, offset, self.total_path_attribute_len) + msg += binpathattrs + offset += 2 + self.total_path_attribute_len + msg += binnlri + return msg + + [email protected]_type(BGP_MSG_KEEPALIVE) +class BGPKeepAlive(BGPMessage): + """BGP-4 KEEPALIVE Message 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 + ========================== =============================================== + marker Marker field. Ignored when encoding. + len Length field. Ignored when encoding. + type Type field. The default is BGP_MSG_KEEPALIVE. + ========================== =============================================== + """ + + _MIN_LEN = BGPMessage._HDR_LEN + + def __init__(self, type_=BGP_MSG_KEEPALIVE, len_=None, marker=None): + super(BGPKeepAlive, self).__init__(marker=marker, len_=len_, + type_=type_) + + @classmethod + def parser(cls, buf): + return {} + + def serialize_tail(self): + return bytearray() + + [email protected]_type(BGP_MSG_NOTIFICATION) +class BGPNotification(BGPMessage): + """BGP-4 NOTIFICATION Message 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 + ========================== =============================================== + marker Marker field. Ignored when encoding. + len Length field. Ignored when encoding. + type Type field. The default is + BGP_MSG_NOTIFICATION. + error_code Error code field. + error_subcode Error subcode field. + data Data field. The default is ''. + ========================== =============================================== + """ + + _PACK_STR = '!BB' + _MIN_LEN = BGPMessage._HDR_LEN + struct.calcsize(_PACK_STR) + + def __init__(self, + error_code, + error_subcode, + data='', + type_=BGP_MSG_NOTIFICATION, len_=None, marker=None): + super(BGPNotification, self).__init__(marker=marker, len_=len_, + type_=type_) + self.error_code = error_code + self.error_subcode = error_subcode + self.data = data + + @classmethod + def parser(cls, buf): + (error_code, error_subcode,) = struct.unpack_from(cls._PACK_STR, + buffer(buf)) + data = bytes(buf[2:]) + return { + "error_code": error_code, + "error_subcode": error_subcode, + "data": data, + } + + def serialize_tail(self): + msg = bytearray(struct.pack(self._PACK_STR, self.error_code, + self.error_subcode)) + msg += self.data + return msg -- 1.8.3.1 ------------------------------------------------------------------------------ October Webinars: Code for Performance Free Intel webinars can help you accelerate application performance. 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