zebra: fix missing vni transition

`show evpn vni detail` doesn't reflect any change in vni transition.
Need to add processing in command of `[no] vni (1-16777215)`.

With the config:
```
!
vni 66
!
vrf vrf1
 vni 88
 exit-vrf
!
```

Before:
```
(config-vrf)# no vni 88
(config-vrf)# do show evpn vni detail
VNI: 66
  Type: L3
  Tenant VRF: default
  L2 VNIs: <- Empty
```

After:
```
(config-vrf)# no vni 88
(config-vrf)# do show evpn vni detail
VNI: 66
  Type: L3
  Tenant VRF: default
  L2 VNIs: 88 <-
```

Signed-off-by: anlan_cs <vic.lan@pica8.com>

1 files changed, 10 insertions, 1 deletions

diff --git a/zebra/zebra_vxlan.c b/zebra/zebra_vxlan.c
index 5a6321ae7e..9fae556dd4 100644
--- a/zebra/zebra_vxlan.c
+++ b/zebra/zebra_vxlan.c
@@ -2090,6 +2090,7 @@ static int zebra_vxlan_handle_vni_transition(struct zebra_vrf *zvrf, vni_t vni,
 					     int add)
 {
 	struct zebra_evpn *zevpn = NULL;
+	struct zebra_l3vni *zl3vni = NULL;
 
 	/* There is a possibility that VNI notification was already received
 	 * from kernel and we programmed it as L2-VNI
@@ -2117,6 +2118,10 @@ static int zebra_vxlan_handle_vni_transition(struct zebra_vrf *zvrf, vni_t vni,
 		/* Free up all remote VTEPs, if any. */
 		zebra_evpn_vtep_del_all(zevpn, 1);
 
+		zl3vni = zl3vni_from_vrf(zevpn->vrf_id);
+		if (zl3vni)
+			listnode_delete(zl3vni->l2vnis, zevpn);
+
 		/* Delete the hash entry. */
 		if (zebra_evpn_vxlan_del(zevpn)) {
 			flog_err(EC_ZEBRA_VNI_DEL_FAILED,
@@ -2172,8 +2177,12 @@ static int zebra_vxlan_handle_vni_transition(struct zebra_vrf *zvrf, vni_t vni,
 		/* Find bridge interface for the VNI */
 		vlan_if = zvni_map_to_svi(vxl->access_vlan,
 					  zif->brslave_info.br_if);
-		if (vlan_if)
+		if (vlan_if) {
 			zevpn->vrf_id = vlan_if->vrf->vrf_id;
+			zl3vni = zl3vni_from_vrf(vlan_if->vrf->vrf_id);
+			if (zl3vni)
+				listnode_add_sort_nodup(zl3vni->l2vnis, zevpn);
+		}
 
 		zevpn->vxlan_if = ifp;
 		zevpn->local_vtep_ip = vxl->vtep_ip;