Handle VN change in interface Notification

Remove the assumption that VN of an interface cannot change without first getting a
notification for NULL VN.

Also fix the following issue.
Also when VN changes for a VMI (clubbing of VMI getting NULL VRF and later new VRF
events into a single event) we were not removing EVPN and Bridge routes for old VRF.

Also added UT to verify this scenario.

Closes-Bug: #1596792
(cherry picked from commit 64ef024)

Change-Id: I037631d09af36e7d191cc0f45a129a99d3c800ea

src/vnsw/agent/oper/vm_interface.cc

@@ -1211,7 +1211,8 @@ void VmInterface::UpdateL3(bool old_ipv4_active, VrfEntry *old_vrf,
                                      policy_change,
                                      old_vrf, old_dhcp_addr);
         }
-        UpdateIpv4InstanceIp(force_update, policy_change, false, old_ethernet_tag);
+        UpdateIpv4InstanceIp(force_update, policy_change, false,
+                             old_ethernet_tag, old_vrf);
         UpdateMetadataRoute(old_ipv4_active, old_vrf);
         UpdateFloatingIp(force_update, policy_change, false, old_ethernet_tag);
         UpdateServiceVlan(force_update, policy_change);
@@ -1298,7 +1299,8 @@ void VmInterface::UpdateL2(bool old_l2_active, VrfEntry *old_vrf,
                            old_layer3_forwarding, policy_change,
                            Ip4Address(), Ip6Address(),
                            MacAddress::FromString(vm_mac_));
-    UpdateIpv4InstanceIp(force_update, policy_change, true, old_ethernet_tag);
+    UpdateIpv4InstanceIp(force_update, policy_change, true, old_ethernet_tag,
+                         old_vrf);
     UpdateIpv6InstanceIp(force_update, policy_change, true, old_ethernet_tag);
     UpdateFloatingIp(force_update, policy_change, true, old_ethernet_tag);
     UpdateAllowedAddressPair(force_update, policy_change, true, old_l2_active,
@@ -1365,9 +1367,8 @@ void VmInterface::ApplyConfigCommon(const VrfEntry *old_vrf,
 void VmInterface::ApplyMacVmBindingConfig(const VrfEntry *old_vrf,
                                           bool old_active,
                                           bool old_dhcp_enable) {
-    if (!IsActive()) {
+    if (!IsActive() || old_vrf != vrf()) {
         DeleteMacVmBinding(old_vrf);
-        return;
     }
 
     //Update DHCP and DNS flag in Interface Class.
@@ -1379,6 +1380,8 @@ void VmInterface::ApplyMacVmBindingConfig(const VrfEntry *old_vrf,
         dns_enabled_ = false;
     }
 
+    if (!IsActive())
+        return;
     UpdateMacVmBinding();
 }
 
@@ -2999,6 +3002,10 @@ void VmInterface::UpdateL2InterfaceRoute(bool old_l2_active, bool force_update,
         force_update = true;
     }
 
+    if (old_vrf && old_vrf != vrf()) {
+        force_update = true;
+    }
+
     //Encap change will result in force update of l2 routes.
     if (force_update) {
         DeleteL2InterfaceRoute(true, old_vrf, old_v4_addr,
@@ -4472,8 +4479,8 @@ bool VmInterface::CopyIp6Address(const Ip6Address &addr) {
 }
 
 void VmInterface::UpdateIpv4InstanceIp(bool force_update, bool policy_change,
-                                       bool l2,
-                                       uint32_t old_ethernet_tag) {
+                                       bool l2, uint32_t old_ethernet_tag,
+                                       VrfEntry *old_vrf) {
     if (l2 && old_ethernet_tag != ethernet_tag()) {
         force_update = true;
     }
@@ -4487,6 +4494,9 @@ void VmInterface::UpdateIpv4InstanceIp(bool force_update, bool policy_change,
                 instance_ipv4_list_.list_.erase(prev);
             }
         } else {
+            if (old_vrf && (old_vrf != vrf())) {
+                prev->DeActivate(this, l2, old_vrf, old_ethernet_tag);
+            }
             prev->Activate(this, force_update||policy_change, l2,
                            old_ethernet_tag);
         }

src/vnsw/agent/oper/vm_interface.h

@@ -741,12 +741,11 @@ class VmInterface : public Interface {
                                 int old_ethernet_tag,
                                 const MacAddress &mac) const;
 
-    void DeleteL2Route(const std::string &vrf_name,
-                       const MacAddress &mac);
     void UpdateVrfAssignRule();
     void DeleteVrfAssignRule();
     void UpdateIpv4InstanceIp(bool force_update, bool policy_change,
-                              bool l2, uint32_t old_ethernet_tag);
+                              bool l2, uint32_t old_ethernet_tag,
+                              VrfEntry *old_vrf);
     void DeleteIpv4InstanceIp(bool l2, uint32_t old_ethernet_tag,
                               VrfEntry *old_vrf);
     void UpdateIpv6InstanceIp(bool force_update, bool policy_change,