IPv6 support for external interfaces

We can now configure external interfaces with IPv6, including DAPNet
support. This includes a rework of how the Router() class handles IP
addresses and offers route redistribution via route-maps + prefix lists
instead of explicit network statements.

The InterfaceList now has three new methods to get the list of IPs for a
router that are external, internal or routable. Routable IPs are defined
as the list of internal IPs where the address scope of the subnet
matches the address scope of the gateway (external) interface.

The BGP AddressFamily class now supports advertising of routes via
route-map. This means we have a route-map, which references prefix lists
that contain routable and internal IPs + their extra routes. For
routable IPs and their extraroutes we set a route target: routable IPs
get the cloud vrf's id, routable extraroutes have a prepended 1 to the
vrf id. This is very much the same as it is currently handled on the
device, though the config was pre-provisioned and only referenced via
route-maps on the respective network statements. This feature is
currently only enabled for IPv6 default and can be enabled for IPv4 with
the config option advertise_bgp_ipv4_routes_via_redistribute. The reason
of doing this is that editing the BGP config tree currently locks up the
whole device config due to requiring a full config resync.

Prefix lists referenced by route-maps that do not contain any prefix
don't appear as config on the device. The referencing route-map treats
non-existing prefix-lists as "always matching". As our expectation of
how this would work was empty prefix-list means "no match", we now have
to adjust our expectations of this feature and always add an entry if
the list would be empty otherwise. This is done via add_deny_if_empty,
which adds a deny for everything. The seq 4242 was deliberately chosen
to not collide with any of our existing rules, not because we saw any
problems with this, but because we didn't want to end up in a situation
where the device locks up because "there is already a rule with that
seq", even though we generally think this should work.

asr1k_neutron_l3/common/config.py

@@ -91,6 +91,10 @@
     cfg.BoolOpt('enable_fwaas_cleaning', default=True, help="Run FWaaS cleaning sync to remove stale FWaaS ACLs, "
                                                             "Class Maps and Service Policies"),
     cfg.IntOpt('fwaas_cleaning_interval', default=300, help="Interval for FWaaS cleaning"),
+    cfg.BoolOpt('advertise_bgp_ipv4_routes_via_redistribute', default=False,
+                help=('Advertise BGP routes (BGPVPN/DAPNets) on IPv4 via redistribute static/connected + route-map '
+                      'instead of using network statements. This avoids the global config lock, that occurs on current '
+                      'firmwares (at least 17.15) when the BGP tree is modified.')),
 ]
 
 ASR1K_L2_OPTS = [

asr1k_neutron_l3/models/netconf_yang/bgp.py

@@ -37,6 +37,7 @@ class BGPConstants(object):
     VRF = "vrf"
     REDISTRIBUTE = "redistribute"
     REDISTRIBUTE_VRF = "redistribute-vrf"
+    REDISTRIBUTE_V6 = "redistribute-v6"
     CONNECTED = "connected"
     STATIC = "static"
     UNICAST = "unicast"
@@ -45,6 +46,7 @@ class BGPConstants(object):
     NUMBER = "number"
     MASK = "mask"
     ROUTE_MAP = "route-map"
+    DEFAULT = "default"
 
 
 class AddressFamilyBase(NyBase):
@@ -106,6 +108,18 @@ def _wrapper_preamble(self, dict, context):
         result = {BGPConstants.ROUTER: result}
         return result
 
+    @classmethod
+    def _get(cls, **kwargs):
+        # make sure the result has a vrf associated
+        # due to the way we filter for our AF (with the ASN included) we always get a result, which
+        # prompts the original _get() method to always return a class, which results in problems when
+        # we want an empty result in case it's not there (should_be_none=True), therefore we filter out
+        # pseudoempty results here
+        result = super()._get(**kwargs)
+        if result and getattr(result, "vrf", None) is None:
+            return None
+        return result
+
     def __init__(self, **kwargs):
         super().__init__(**kwargs)
 
@@ -167,26 +181,38 @@ def __parameters__(cls):
             {'key': 'vrf', 'yang-key': 'name'},
             {'key': 'networks', 'yang-path': 'ipv4-unicast/network', 'yang-key': BGPConstants.WITH_MASK,
              'type': [NetworkV4], 'default': []},
+            {'key': 'redistribute_connected_with_rm', 'yang-key': 'route-map',
+             'yang-path': 'ipv4-unicast/redistribute-vrf/connected'},
+            {'key': 'redistribute_static_with_rm', 'yang-key': 'route-map',
+             'yang-path': 'ipv4-unicast/redistribute-vrf/static/default'},
         ]
 
     def to_dict(self, context):
         if self.vrf is None:
             return {}
 
-        vrf = {
-            BGPConstants.NAME: self.vrf,
-            BGPConstants.IPV4_UNICAST: {
-                xml_utils.OPERATION: NC_OPERATION.PUT,
-                BGPConstants.NETWORK: {
-                    BGPConstants.WITH_MASK: [
-                        net.to_dict(context) for net in sorted(self.networks, key=lambda x: (x.number, x.mask))
-                    ],
-                },
-            }
+        ipv4_unicast = {
+            xml_utils.OPERATION: NC_OPERATION.PUT,
+            BGPConstants.NETWORK: {
+                BGPConstants.WITH_MASK: [
+                    net.to_dict(context) for net in sorted(self.networks, key=lambda x: (x.number, x.mask))
+                ],
+            },
         }
+        if self.redistribute_connected_with_rm or self.redistribute_static_with_rm:
+            redist = {}
+            if self.redistribute_connected_with_rm:
+                redist[BGPConstants.CONNECTED] = {BGPConstants.ROUTE_MAP: self.redistribute_connected_with_rm}
+            if self.redistribute_static_with_rm:
+                redist[BGPConstants.STATIC] = {
+                    BGPConstants.DEFAULT: {BGPConstants.ROUTE_MAP: self.redistribute_static_with_rm}}
+            ipv4_unicast[BGPConstants.REDISTRIBUTE_VRF] = redist
 
         result = {
-            BGPConstants.VRF: vrf,
+            BGPConstants.VRF: {
+                BGPConstants.NAME: self.vrf,
+                BGPConstants.IPV4_UNICAST: ipv4_unicast,
+            }
         }
         return result
 
@@ -224,24 +250,35 @@ def __parameters__(cls):
             {'key': 'vrf', 'yang-key': 'name'},
             {'key': 'networks', 'yang-path': BGPConstants.IPV6_UNICAST, 'yang-key': BGPConstants.NETWORK,
              'type': [NetworkV6], 'default': []},
+            {'key': 'redistribute_connected_with_rm', 'yang-key': 'route-map',
+             'yang-path': 'ipv6-unicast/redistribute-v6/connected'},
+            {'key': 'redistribute_static_with_rm', 'yang-key': 'route-map',
+             'yang-path': 'ipv6-unicast/redistribute-v6/static'},
         ]
 
     def to_dict(self, context):
         if self.vrf is None:
             return {}
 
-        vrf = {
-            BGPConstants.NAME: self.vrf,
-            BGPConstants.IPV6_UNICAST: {
-                xml_utils.OPERATION: NC_OPERATION.PUT,
-                BGPConstants.NETWORK: [
-                    net.to_dict(context) for net in sorted(self.networks, key=lambda x: x.number)
-                ],
-            }
+        ipv6_unicast = {
+            xml_utils.OPERATION: NC_OPERATION.PUT,
+            BGPConstants.NETWORK: [
+                net.to_dict(context) for net in sorted(self.networks, key=lambda x: x.number)
+            ],
         }
+        if self.redistribute_connected_with_rm or self.redistribute_static_with_rm:
+            redist = {}
+            if self.redistribute_connected_with_rm:
+                redist[BGPConstants.CONNECTED] = {BGPConstants.ROUTE_MAP: self.redistribute_connected_with_rm}
+            if self.redistribute_static_with_rm:
+                redist[BGPConstants.STATIC] = {BGPConstants.ROUTE_MAP: self.redistribute_static_with_rm}
+            ipv6_unicast[BGPConstants.REDISTRIBUTE_V6] = redist
 
         result = {
-            BGPConstants.VRF: vrf,
+            BGPConstants.VRF: {
+                BGPConstants.NAME: self.vrf,
+                BGPConstants.IPV6_UNICAST: ipv6_unicast,
+            }
         }
         return result
 

asr1k_neutron_l3/models/netconf_yang/l3_interface.py

@@ -463,3 +463,9 @@ def __parameters__(cls):
 
     def to_dict(self, context):
         return {L3Constants.PREFIX: self.prefix.lower()}
+
+    @property
+    def address(self):
+        if self.prefix:
+            return self.prefix.split("/")[0]
+        return None

asr1k_neutron_l3/models/netconf_yang/prefix.py

@@ -68,6 +68,14 @@ class PrefixBase(NyBase):
     LIST_KEY = None
     ITEM_KEY = PrefixConstants.PREFIX_LISTS
 
+    KNOWN_PREFIXES = [
+        "ext-", "snat-", "route-",
+        "routable4-", "routable6-",
+        "routable-extraroutes4-", "routable-extraroutes6-",
+        "internal4-", "internal6-",
+        "internal-extraroutes4-", "internal-extraroutes6-",
+    ]
+
     @classmethod
     def __parameters__(cls):
         return [

asr1k_neutron_l3/models/netconf_yang/route_map.py

@@ -68,6 +68,11 @@ class RouteMap(NyBase):
     LIST_KEY = None
     ITEM_KEY = RouteMapConstants.ROUTE_MAP
 
+    KNOWN_PREFIXES = [
+        "exp-", "pbr-",
+        "bgp-redistribute4-", "bgp-redistribute6-",
+    ]
+
     @classmethod
     def __parameters__(cls):
         return [
@@ -81,8 +86,11 @@ def __init__(self, **kwargs):
 
     @property
     def neutron_router_id(self):
-        if self.name is not None and (self.name.startswith('exp-') or self.name.startswith('pbr-')):
-            return utils.vrf_id_to_uuid(self.name[4:])
+        if self.name:
+            for prefix in self.KNOWN_PREFIXES:
+                if self.name.startswith(prefix):
+                    return utils.vrf_id_to_uuid(self.name[len(prefix):])
+        return None
 
     def to_dict(self, context):
         result = OrderedDict()
@@ -195,7 +203,7 @@ def to_dict(self, context):
                 entry[RouteMapConstants.IP] = {
                     RouteMapConstants.ADDRESS: {RouteMapConstants.PREFIX_LIST: self.prefix_list}}
             if self.prefix_list_v6:
-                entry[RouteMapConstants.IP] = {
+                entry[RouteMapConstants.IPV6] = {
                     RouteMapConstants.ADDRESS: {RouteMapConstants.PREFIX_LIST: self.prefix_list_v6}}
 
         if self.access_list is not None:

asr1k_neutron_l3/models/neutron/l3/bgp.py

@@ -25,14 +25,16 @@ class AddressFamilyBase(base.Base):
     YANG_BGP_CLASS = None
     YANG_BGP_NETWORK_CLASS = None
 
-    def __init__(self, vrf, asn=None, has_routable_interface=False, rt_export=[],
-                 connected_cidrs=[], routable_networks=[], extra_routes=[]):
+    def __init__(self, vrf, asn=None, has_routable_interface=False, enable_af=True, rt_export=[],
+                 redistribute_map=None, connected_cidrs=[], routable_networks=[], extra_routes=[]):
         super().__init__()
         self.vrf = utils.uuid_to_vrf_id(vrf)
+        self.enable_af = enable_af
         self.has_routable_interface = has_routable_interface
         self.asn = asn
         self.enable_bgp = False
         self.rt_export = rt_export
+        self.redistribute_map = redistribute_map
         self.routable_networks = routable_networks
         self.networks = set()
 
@@ -49,11 +51,13 @@ def __init__(self, vrf, asn=None, has_routable_interface=False, rt_export=[],
             self.networks.add(net)
         self.networks = list(self.networks)
 
-        if self.has_routable_interface or len(self.rt_export) > 0:
+        if self.enable_af and (self.has_routable_interface or len(self.rt_export) > 0):
             self.enable_bgp = True
 
         self._rest_definition = self.YANG_BGP_CLASS(vrf=self.vrf, asn=self.asn, enable_bgp=self.enable_bgp,
-                                                    networks=self.networks)
+                                                    networks=self.networks,
+                                                    redistribute_static_with_rm=redistribute_map,
+                                                    redistribute_connected_with_rm=redistribute_map)
 
     def get(self):
         return self.YANG_BGP_CLASS.get(self.vrf, asn=self.asn, enable_bgp=self.enable_bgp)