Set IP/MAC address on VPNaaS gateway port (OVN)

Fix an issue with missing route announcements for
the VPN external port in a setup with OVN, BGP (ovn-bgp-agent)
and VPNaaS. The ovn-bgp-agent won't annouce the address of
the VPN gateway port if its OVN logical switch port only
has address=[unknown].
To set the address on the LSP explicitly, add the device owner
network:vpn_router_gateway to the reasons to do so.

Closes-Bug: #2088286
Change-Id: Ic04833333a04064c2fbd7fb2700d35f2312aef7e

neutron/common/_constants.py

@@ -96,3 +96,7 @@ LOWEST_AGENT_BINDING_INDEX = 1
 
 # TODO(ralonsoh): move this constant to neutron_lib.plugins.ml2.ovs_constants
 DEFAULT_BR_INT = 'br-int'
+
+# TODO(bpetermann): Remove here after neutron-lib is bumped
+DEVICE_OWNER_VPN_ROUTER_GW = (constants.DEVICE_OWNER_NETWORK_PREFIX +
+                              "vpn_router_gateway")

neutron/plugins/ml2/drivers/ovn/mech_driver/ovsdb/ovn_client.py

@@ -48,6 +48,7 @@ from ovsdbapp.backend.ovs_idl import idlutils
 import tenacity
 
 from neutron._i18n import _
+from neutron.common import _constants as n_const
 from neutron.common.ovn import acl as ovn_acl
 from neutron.common.ovn import constants as ovn_const
 from neutron.common.ovn import utils
@@ -379,6 +380,7 @@ class OVNClient:
         address6_scope_id = ""
         dhcpv4_options = self._get_port_dhcp_options(port, const.IP_VERSION_4)
         dhcpv6_options = self._get_port_dhcp_options(port, const.IP_VERSION_6)
+        device_owner = port.get('device_owner', '')
         mtu = ''
         if vtep_physical_switch:
             vtep_logical_switch = bp_info.bp_param.get('vtep-logical-switch')
@@ -446,12 +448,13 @@ class OVNClient:
             addresses = []
             port_security, new_macs = (
                 self._get_allowed_addresses_from_port(port))
+            is_vpn_gw_port = device_owner == n_const.DEVICE_OWNER_VPN_ROUTER_GW
             # TODO(egarciar): OVN supports MAC learning from v21.03. This
             # if-else block is stated so as to keep compatibility with older
             # OVN versions and should be removed in the future.
             if self._sb_idl.is_table_present('FDB'):
                 if (port_security or port_type or dhcpv4_options or
-                        dhcpv6_options):
+                        dhcpv6_options or is_vpn_gw_port):
                     addresses.append(address)
                     addresses.extend(new_macs)
             else:
@@ -511,7 +514,6 @@ class OVNClient:
                 'vtep', ovn_const.LSP_TYPE_LOCALPORT, 'router'):
             options.update({ovn_const.LSP_OPTIONS_MCAST_FLOOD_REPORTS: 'true'})
 
-        device_owner = port.get('device_owner', '')
         sg_ids = ' '.join(utils.get_lsp_security_groups(port))
         return OvnPortInfo(port_type, options, addresses, port_security,
                            parent_name, tag, dhcpv4_options, dhcpv6_options,