zebra: L3VNI to L2VNI conversion is not handled

After removal of L3VNI config, the VNI should become an L2VNI if a VxLAN
interface is present for the VNI. This case is not handled in the code.

Changes:
1. After unconfiguring L3VNI, create an L2VNI if VxLAN interface is present
for the VNI.
2. Trigger an update to BGP.
3. Read MAC and ARP entries from kernel.

This PR fixes the issue only for route type-2, 3 and 5. This PR does not address
states regarding route type-1, 4 and multicast group for VxLAN interface.

Signed-off-by: Ameya Dharkar <adharkar@vmware.com>

diff --git a/zebra/zebra_vxlan.c b/zebra/zebra_vxlan.c
index 28bed846cf86fabfd0404bab3a23da3ca0a9080a..9fc09631584a47d00ebc5deff2bd80f9680b5d7f 100644 (file)
--- a/zebra/zebra_vxlan.c
+++ b/zebra/zebra_vxlan.c
@@ -1992,7 +1992,10 @@ static void zevpn_add_to_l3vni_list(struct hash_bucket *bucket, void *ctxt)
 }
 
 /*
- *  handle transition of vni from l2 to l3 and vice versa
+ * Handle transition of vni from l2 to l3 and vice versa.
+ * This function handles only the L2VNI add/delete part of
+ * the above transition.
+ * L3VNI add/delete is handled by the calling functions.
  */
 static int zebra_vxlan_handle_vni_transition(struct zebra_vrf *zvrf, vni_t vni,
                                             int add)
@@ -2033,11 +2036,71 @@ static int zebra_vxlan_handle_vni_transition(struct zebra_vrf *zvrf, vni_t vni,
                        return -1;
                }
        } else {
-               /* TODO_MITESH: This needs to be thought through. We don't have
-                * enough information at this point to reprogram the vni as
-                * l2-vni. One way is to store the required info in l3-vni and
-                * used it solely for this purpose
-                */
+               struct zebra_ns *zns;
+               struct route_node *rn;
+               struct interface *ifp;
+               struct zebra_if *zif;
+               struct zebra_l2info_vxlan *vxl;
+               struct interface *vlan_if;
+               bool found = false;
+
+               if (IS_ZEBRA_DEBUG_VXLAN)
+                       zlog_debug("Adding L2-VNI %u - transition from L3-VNI",
+                                  vni);
+
+               /* Find VxLAN interface for this VNI. */
+               zns = zebra_ns_lookup(NS_DEFAULT);
+               for (rn = route_top(zns->if_table); rn; rn = route_next(rn)) {
+                       ifp = (struct interface *)rn->info;
+                       if (!ifp)
+                               continue;
+                       zif = ifp->info;
+                       if (!zif || zif->zif_type != ZEBRA_IF_VXLAN)
+                               continue;
+
+                       vxl = &zif->l2info.vxl;
+                       if (vxl->vni == vni) {
+                               found = true;
+                               break;
+                       }
+               }
+
+               if (!found) {
+                       if (IS_ZEBRA_DEBUG_VXLAN)
+                               zlog_err(
+                                       "Adding L2-VNI - Failed to find VxLAN interface for VNI %u",
+                                       vni);
+                       return -1;
+               }
+
+               /* Create VNI hash entry for L2VNI */
+               zevpn = zebra_evpn_lookup(vni);
+               if (zevpn)
+                       return 0;
+
+               zevpn = zebra_evpn_add(vni);
+               if (!zevpn) {
+                       flog_err(EC_ZEBRA_VNI_ADD_FAILED,
+                                "Adding L2-VNI - Failed to add VNI hash, VNI %u",
+                                vni);
+
+                       return -1;
+               }
+
+               /* Find bridge interface for the VNI */
+               vlan_if = zvni_map_to_svi(vxl->access_vlan,
+                                         zif->brslave_info.br_if);
+               if (vlan_if)
+                       zevpn->vrf_id = vlan_if->vrf_id;
+
+               zevpn->vxlan_if = ifp;
+               zevpn->local_vtep_ip = vxl->vtep_ip;
+
+               /* Inform BGP if the VNI is up and mapped to a bridge. */
+               if (if_is_operative(ifp) && zif->brslave_info.br_if) {
+                       zebra_evpn_send_add_to_client(zevpn);
+                       zebra_evpn_read_mac_neigh(zevpn, ifp);
+               }
        }
 
        return 0;
@@ -5201,6 +5264,7 @@ int zebra_vxlan_process_vrf_vni_cmd(struct zebra_vrf *zvrf, vni_t vni,
 
        if (add) {
 
+               /* Remove L2VNI if present */
                zebra_vxlan_handle_vni_transition(zvrf, vni, add);
 
                /* check if the vni is already present under zvrf */
@@ -5295,6 +5359,7 @@ int zebra_vxlan_process_vrf_vni_cmd(struct zebra_vrf *zvrf, vni_t vni,
                zvrf->l3vni = 0;
                zl3vni_del(zl3vni);
 
+               /* Add L2VNI for this VNI */
                zebra_vxlan_handle_vni_transition(zvrf, vni, add);
        }
        return 0;