133 lines
5.5 KiB
Python
133 lines
5.5 KiB
Python
# Copyright 2018 Canonical Ltd.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import charmhelpers.core as ch_core
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import charmhelpers.contrib.network.ip as ch_net_ip
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from charms import reactive
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import netaddr
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class BGPEndpoint(reactive.Endpoint):
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def generate_asn(self):
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"""
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Generate unique 32-bit Private Use [RFC6996] ASn.
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This is useful to automate configuration of BGP routers that is part
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of a Clos Network Topology with a Layer 3-Only routed design. [RFC7938]
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Assumption:
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- Unit has a IPv4 address and it is unique to the deployment.
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Implementation:
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- A private 32-bit ASn has a range of 4 200 000 000 - 4 294 967 294
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which leaves us with 94 967 294 possible endpoints.
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- Within a deployment it is less likelly that the 4 most significant
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bits of the IP address differ between units.
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- If we cap the 4 most significant bits of the IPv4 address to be
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within the range of 0 and 4, the decimal representation of the
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resulting IPv4 address fits nicely into that range.
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Note:
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- This implementation generates ASn in the following range:
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4 211 081 215 - 4 294 967 294
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- Leaving the following range for any static configuration needs:
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4 200 000 000 - 4 211 081 214
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"""
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asn_base = 4211081215
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mask = netaddr.IPAddress('4.255.255.255')
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unit_ip = netaddr.IPAddress(
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ch_core.hookenv.unit_get('private-address'))
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masked_ip = unit_ip & mask
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asn = asn_base + int(masked_ip)
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return asn
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def publish_info(self, asn=None, passive=False, bindings=None):
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"""
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Publish the AS Number and IP address of any extra-bindings of this
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BGP Endpoint over the relationship.
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If no AS Number is provided a unique 32-bit Private Use [RFC6996] ASn
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will be generated.
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:param asn: AS Number to publish. Autogenerated if not provided.
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:param passive: Advertise that we wish to be configured as passive
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neighbour.
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:param bindings: List bindings advertised as links to speak BGP on.
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"""
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if asn:
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myasn = asn
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else:
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myasn = self.generate_asn()
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# network_get will return addresses for bindings regardless of them
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# being bound to a network space. detect actual space bindings by
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# comparing returned addresses to what we have for the relation itself.
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for relation in self.relations:
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rel_network = ch_core.hookenv.network_get(
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self.expand_name('{endpoint_name}'),
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relation_id=relation.relation_id)
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rel_addrs = [a['address']
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for a in
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rel_network['bind-addresses'][0]['addresses']]
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actual_bindings = []
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if bindings is None:
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continue
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for binding in bindings:
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bind_network = ch_core.hookenv.network_get(
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binding,
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relation_id=relation.relation_id)
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bind_addrs = [a['address']
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for a in
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bind_network['bind-addresses'][0]['addresses']]
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if not set(bind_addrs).issubset(set(rel_addrs)):
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actual_bindings.extend(
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bind_network['bind-addresses'][0]['addresses'])
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relation.to_publish['asn'] = myasn
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relation.to_publish['bindings'] = actual_bindings
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relation.to_publish['passive'] = passive
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ch_core.hookenv.log("to_publish: '{}'".format(relation.to_publish))
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def get_received_info(self):
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neighbors = []
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for relation in self.relations:
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for unit in relation.units:
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if not ('asn' in unit.received and
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'bindings' in unit.received):
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ch_core.hookenv.log('Skip get_received_info() '
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'relation incomplete...',
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level=ch_core.hookenv.DEBUG)
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continue
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links = []
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for addrinfo in unit.received['bindings']:
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# filter list of networks to those we have interfaces
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# configured for
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ip = ch_net_ip.get_address_in_network(addrinfo['cidr'])
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if ip:
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links.append(
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{'local': ip,
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'remote': addrinfo['address'],
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'cidr': addrinfo['cidr']}
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)
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ch_core.hookenv.log("links: '{}'".format(links))
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neighbors.append({
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'asn': unit.received['asn'],
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'links': links,
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'relation_id': relation.relation_id,
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'remote_unit_name': unit.unit_name,
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'passive': unit.received['passive'],
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})
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return neighbors
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