This Jira is to address below two issues:

Issue 1:

When VM having multiple both TCP and UDP sessions are established, when such VM is deleted, we were only taking care of deleting flows either related to TCP or UDP session which is incorrect. This been resulting in huge number of table=44 flows left over after deletion of VM.

Changes done.

1) Changes done to take care of cleaning of both TCP and UDP session and it's respective flows(table 44/46) on deletion of VM.

2) Changes done to change the key on the table=44 flow to have internal ip/port instead of external ip/port. As a result, when table=46 flow expiry, we can still go ahead construct table=44 flow key to delete without refering the intext-ip-port-map DS.

3) Changes done to address deletion of table 44 and table 46 flows whenever the subnet is removed from the Router.

Issue 2:

Description: Whenever a last VM part of a given VRF is deleted/migrated, it is required to delete 'dpn-vpninterfaces-list' entry for given dpn-id from 'odl-l3vpn:neutron-router-dpns' Operational DS. This trigger re-election of new Napt Switch which has VRF presence. But, when 2 VMs part of same VRF on a same DPN deleted symultanously, then there are chances that both of these event doesn't delete 'dpn-vpninterfaces-list' entry for the DPN which results in non-triggering on new Napt Switch election. As a result, the SNAT reverse traffic initiated from Non-Napt Switch fail as FIB routes will not be availabe to carry back traffic to non-napt switch.

Solution: Changes are done to make sure the 'dpn-vpninterfaces-list' entry for DPN is deleted properly when last VM on that DPN is deleted for a given VRF.