Add support for parsing the Path Attribute: BGP Prefix-SID (Type 40) …

…in BGP UPDATE Message (#167)

* 🎨 Style(__init__.py): replace "Sid" with "SID"

* ✨ Feat(bgpprefixsid.py): add support for parsing the Path Attribute: BGP Prefix-SID (Type 40)

Refer:
https://github.com/Exa-Networks/exabgp/blob/main/src/exabgp/bgp/message/update/attribute/sr/prefixsid.py

* ✅ Test(test_bgpprefixsid.py): add unittest and format result

* 💚 Fix-ci(ci.yml): remove Python 2.7.x from the CI matrix
Refer: actions/setup-python#672

* 🔥 Prune(.travis.yml): remove Travis CI

.github/workflows/ci.yml

@@ -17,12 +17,11 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        # https://docs.github.com/en/actions/using-github-hosted-runners/about-github-hosted-runners#supported-runners-and-hardware-resources
+        # https://docs.github.com/en/actions/using-github-hosted-runners/about-github-hosted-runners/about-github-hosted-runners#supported-runners-and-hardware-resources
         os: [ ubuntu-20.04, macos-latest, windows-latest ]
-        python-version: [ "2.7", "3.6", "3.x" ]
+        python-version: [ "3.6", "3.x" ]
         exclude:
-          - os: windows-latest
-            python-version: "2.7"
+          - python-version: "3.x"
 
     steps:
       - uses: actions/checkout@v3

yabgp/common/constants.py

@@ -89,6 +89,7 @@
 BGPTYPE_TUNNEL_ENCAPS_ATTR = 23  # RFC5512
 BGPTYPE_LINK_STATE = 29
 BGPTYPE_LARGE_COMMUNITY = 32
+BGPTYPE_BGP_PREFIX_SID = 40  # RFC8669 & RFC9252
 BGPTYPE_ATTRIBUTE_SET = 128
 
 # BGP Tunnel Encapsulation Attribute Tunnel Types

yabgp/message/attribute/__init__.py

@@ -46,6 +46,7 @@ class AttributeFlag(int):
     PARTIAL = 0x20  # 32  RFC 4271
     TRANSITIVE = 0x40  # 64  RFC 4271
     OPTIONAL = 0x80  # 128 RFC 4271
+
     # OPTIONAL_TRANSITIVE = 0xc0  # 192 RFC 4271
 
     def __str_(self):
@@ -110,6 +111,7 @@ class AttributeID(int):
     Traffic_Engineering = 0x18  # 24  [RFC5543]
     IPv6_Address_Specific_Extended_Community = 0x19  # 25  [RFC5701]
     LARGE_COMMUNITY = 0x20  # 32  [8092]
+    BGP_PREFIX_SID = 0x28  # 40 [RFC8669 & RFC9252]
     LINKSTATE = 0x1d
     ATTR_SET = 0x80  # 128 [RFC6368]
 

yabgp/message/attribute/linkstate/__init__.py

@@ -52,8 +52,8 @@
 from .link.unidirect_avail_bw import UnidirectAvailBw  # noqa
 from .link.unidirect_bw_util import UnidirectBwUtil  # noqa
 from .link.extend_admin_group import ExtendedAdminGroup  # noqa
-from .link.srv6_end_x_sid import SRv6EndXSid  # noqa
-from .link.srv6_lan_end_x_sid import SRv6LANEndXSid  # noqa
+from .link.srv6_end_x_sid import SRv6EndXSID  # noqa
+from .link.srv6_lan_end_x_sid import SRv6LANEndXSID  # noqa
 from .link.srv6_sid import SRv6SID  # noqa
 from .prefix.prefix_metric import PrefixMetric  # noqa
 from .prefix.prefix_sid import PrefixSID  # noqa

yabgp/message/attribute/linkstate/link/srv6_end_x_sid.py

@@ -23,7 +23,7 @@
 
 
 @LinkState.register()
-class SRv6EndXSid(TLV):
+class SRv6EndXSID(TLV):
     """
     SRv6 End.X SID
     """

yabgp/message/attribute/linkstate/link/srv6_lan_end_x_sid.py

@@ -25,7 +25,7 @@
 
 @LinkState.register(_type=1107)  # IS-IS
 @LinkState.register(_type=1108)  # OSPFv3
-class SRv6LANEndXSid(TLV):
+class SRv6LANEndXSID(TLV):
     """
     SRv6 LAN End.X SID
 

yabgp/message/attribute/sr/__init__.py

@@ -0,0 +1,19 @@
+# Copyright 2024 Cisco Systems, Inc.
+# All rights reserved.
+#
+# 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.
+
+from .bgpprefixsid import BGPPrefixSID  # noqa
+from .srv6.l3service import SRv6L3Service  # noqa
+from .srv6.sidinformation import SRv6SIDInformation  # noqa
+from .srv6.sidstructure import SRv6SIDStructure  # noqa

yabgp/message/attribute/sr/bgpprefixsid.py

@@ -0,0 +1,83 @@
+# Copyright 2024 Cisco Systems, Inc.
+# All rights reserved.
+#
+# 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 struct
+
+import binascii
+
+from yabgp.message.attribute import Attribute, AttributeFlag, AttributeID
+
+
+class BGPPrefixSID(Attribute):
+    """
+    BGP Prefix SID
+
+    Original: https://datatracker.ietf.org/doc/html/rfc8669#section-3
+    Extend: https://datatracker.ietf.org/doc/html/rfc9252#section-2
+    """
+
+    ID = AttributeID.BGP_PREFIX_SID
+    FLAG = AttributeFlag.OPTIONAL + AttributeFlag.TRANSITIVE
+
+    registered_tlvs = dict()
+
+    def __init__(self, value, hex_value=None):
+        self.value = value
+        self.hex_value = hex_value
+
+    @classmethod
+    def register(cls, _type=None):
+        """
+
+        :param _type:
+        :return:
+        """
+
+        def decorator(klass):
+            """
+
+            :param klass:
+            :return:
+            """
+            _id = klass.TYPE if _type is None else _type
+            if _id in cls.registered_tlvs:
+                raise RuntimeError('Duplicated attribute type')
+            cls.registered_tlvs[_id] = klass
+            return klass
+
+        return decorator
+
+    @classmethod
+    def unpack(cls, data):
+        """
+
+        :param data:
+        :return:
+        """
+        tlvs = []
+        while data:
+            type_code = data[0]  # Note: Type = 1 octet
+            length = struct.unpack('!H', data[1:3])[0]  # Note: Length = 2 octet
+            value = data[3: 3 + length]
+
+            if type_code in cls.registered_tlvs:
+                tlvs.append(cls.registered_tlvs[type_code].unpack(value))
+            else:
+                tlvs.append({
+                    'type': type_code,
+                    'value': str(binascii.b2a_hex(value))
+                })
+            data = data[3 + length:]
+        return tlvs

yabgp/message/attribute/sr/srv6/__init__.py

@@ -0,0 +1,8 @@
+#    +---------------+---------------------------------+----------+-----------------+
+#    |    TLV Code   | Description                     | Length   | Reference       |
+#    |     Point     |                                 |          |                 |
+#    +---------------+---------------------------------+----------+-----------------+
+#    |      5        | SRv6 L3 Service TLV             | variable | Section 2       |
+#    |      1        | SRv6 SID Information Sub-TLV    | variable | Section 3.1     |
+#    |      1        | SRv6 SID Structure Sub-Sub-TLV  |    6     | Section 3.2.1   |
+#    +---------------+---------------------------------+----------+-----------------+

yabgp/message/attribute/sr/srv6/l3service.py

@@ -0,0 +1,96 @@
+# Copyright 2024 Cisco Systems, Inc.
+# All rights reserved.
+#
+# 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 struct
+
+import binascii
+
+from yabgp.tlv import TLV
+from ..bgpprefixsid import BGPPrefixSID
+
+
+# 2.  SRv6 Services TLVs
+#
+#  0                   1                   2                   3
+#  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+# +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+# |   TLV Type    |         TLV Length            |   RESERVED    |
+# +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+# |   SRv6 Service Sub-TLVs                                      //
+# +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+#
+#                   Figure 1: SRv6 Service TLVs
+
+
+@BGPPrefixSID.register()
+class SRv6L3Service(TLV):
+    """
+    SRv6 L3 Service
+    """
+    TYPE = 5  # https://datatracker.ietf.org/doc/html/rfc9252.html#section-2
+    TYPE_STR = 'srv6_l3_service'
+
+    registered_tlvs = dict()
+
+    @classmethod
+    def register(cls, _type=None):
+        """
+
+        :param _type:
+        :return:
+        """
+
+        def decorator(klass):
+            """
+
+            :param klass:
+            :return:
+            """
+            _id = klass.TYPE if _type is None else _type
+            if _id in cls.registered_tlvs:
+                raise RuntimeError('Duplicated SRv6 Service Sub-TLV type')
+            cls.registered_tlvs[_id] = klass
+            return klass
+
+        return decorator
+
+    @classmethod
+    def unpack(cls, data):
+        """
+
+        :param data:
+        :return:
+        """
+        tlvs = []
+
+        # reserved = data[0:1]  # Note: First byte is reserved
+        data = data[1:]
+        while data:
+            srv6_service_sub_tlv_type_code = data[0]  # Note: Type = 1 octet
+            srv6_service_sub_tlv_length = struct.unpack('!H', data[1:3])[0]  # Note: Length = 2 octet
+            value = data[3: 3 + srv6_service_sub_tlv_length]
+
+            if srv6_service_sub_tlv_type_code in cls.registered_tlvs:
+                tlvs.append(cls.registered_tlvs[srv6_service_sub_tlv_type_code].unpack(value))
+            else:
+                tlvs.append({
+                    'type': srv6_service_sub_tlv_type_code,
+                    'value': str(binascii.b2a_hex(value))
+                })
+            data = data[3 + srv6_service_sub_tlv_length:]
+        value = {
+            'srv6_service_sub_tlvs': tlvs
+        }
+        return {cls.TYPE_STR: value}