zebra: send a local-mac del to bgpd on mac mod to remote

When events cross paths between bgp and zebra bgpd could end up with a
dangling local MAC entry. Consider the following sequence of events on
rack-1 -
1. MAC1 has MM sequence number 1 and points to rack-3
2. Now a packet is rxed locally on rack-1 and rack-2 (simultaneously) with
source-mac=MAC1.
3. This would cause rack-1 and rack-2 to set the MM seq to 2 and
simultaneously report the MAC as local.
4. Now let's say on rack-1 zebra's MACIP_ADD is in bgpd's queue. bgpd
accepts rack-3's update and sends a remote MACIP add to zebra with MM=2.
5. zebra updates the MAC entry from local=>remote.
6. bgpd now processes zebra's "stale local" making it the best path.
However zebra no longer has a local MAC entry.

At this point bgpd and zebra are effectively out of sync i.e. bgpd has a
local-MAC which is not present in the kernel or in zebra.

To handle this window zebra should send a local MAC delete to bgpd on
modifying its cache to remote.

Ticket: CM-22687
Reviewed By: CCR-7935

Signed-off-by: Anuradha Karuppiah <anuradhak@cumulusnetworks.com>

diff --git a/zebra/zebra_vxlan.c b/zebra/zebra_vxlan.c
index 58cf6eb30f1338c9a05ef01244d1abaae1791ad3..9ecf83433373fe82deeb190f16e4290d02800f02 100644 (file)
--- a/zebra/zebra_vxlan.c
+++ b/zebra/zebra_vxlan.c
@@ -148,8 +148,7 @@ static void zvni_mac_del_all(zebra_vni_t *zvni, int uninstall, int upd_client,
 static zebra_mac_t *zvni_mac_lookup(zebra_vni_t *zvni, struct ethaddr *macaddr);
 static int zvni_mac_send_add_to_client(vni_t vni, struct ethaddr *macaddr,
                                       uint8_t flags, uint32_t seq);
-static int zvni_mac_send_del_to_client(vni_t vni, struct ethaddr *macaddr,
-                                      uint8_t flags);
+static int zvni_mac_send_del_to_client(vni_t vni, struct ethaddr *macaddr);
 static zebra_vni_t *zvni_map_vlan(struct interface *ifp,
                                  struct interface *br_if, vlanid_t vid);
 static int zvni_mac_install(zebra_vni_t *zvni, zebra_mac_t *mac);
@@ -2321,7 +2320,7 @@ static void zvni_mac_del_hash_entry(struct hash_backet *backet, void *arg)
                                  &wctx->r_vtep_ip))) {
                if (wctx->upd_client && (mac->flags & ZEBRA_MAC_LOCAL)) {
                        zvni_mac_send_del_to_client(wctx->zvni->vni,
-                                                   &mac->macaddr, mac->flags);
+                                                   &mac->macaddr);
                }
 
                if (wctx->uninstall)
@@ -2408,18 +2407,10 @@ static int zvni_mac_send_add_to_client(vni_t vni, struct ethaddr *macaddr,
 /*
  * Inform BGP about local MAC deletion.
  */
-static int zvni_mac_send_del_to_client(vni_t vni, struct ethaddr *macaddr,
-                                      uint8_t mac_flags)
+static int zvni_mac_send_del_to_client(vni_t vni, struct ethaddr *macaddr)
 {
-       uint8_t flags = 0;
-
-       if (CHECK_FLAG(mac_flags, ZEBRA_MAC_STICKY))
-               SET_FLAG(flags, ZEBRA_MACIP_TYPE_STICKY);
-       if (CHECK_FLAG(mac_flags, ZEBRA_MAC_DEF_GW))
-               SET_FLAG(flags, ZEBRA_MACIP_TYPE_GW);
-
-       return zvni_macip_send_msg_to_client(vni, macaddr, NULL, flags,
-                                            0, ZEBRA_MACIP_DEL);
+       return zvni_macip_send_msg_to_client(vni, macaddr, NULL, 0 /* flags */,
+                                            0 /* seq */, ZEBRA_MACIP_DEL);
 }
 
 /*
@@ -4218,6 +4209,10 @@ static void process_remote_macip_add(vni_t vni,
                        }
                }
 
+               /* Remove local MAC from BGP. */
+               if (CHECK_FLAG(mac->flags, ZEBRA_MAC_LOCAL))
+                       zvni_mac_send_del_to_client(zvni->vni, macaddr);
+
                /* Set "auto" and "remote" forwarding info. */
                UNSET_FLAG(mac->flags, ZEBRA_MAC_LOCAL);
                memset(&mac->fwd_info, 0, sizeof(mac->fwd_info));
@@ -4238,6 +4233,7 @@ static void process_remote_macip_add(vni_t vni,
 
                /* Install the entry. */
                zvni_mac_install(zvni, mac);
+
        }
 
        /* Update seq number. */
@@ -5631,7 +5627,7 @@ int zebra_vxlan_check_del_local_mac(struct interface *ifp,
                        ifp->ifindex, vni);
 
        /* Remove MAC from BGP. */
-       zvni_mac_send_del_to_client(zvni->vni, macaddr, mac->flags);
+       zvni_mac_send_del_to_client(zvni->vni, macaddr);
 
        /*
         * If there are no neigh associated with the mac delete the mac
@@ -5742,7 +5738,7 @@ int zebra_vxlan_local_mac_del(struct interface *ifp, struct interface *br_if,
        zvni_process_neigh_on_local_mac_del(zvni, mac);
 
        /* Remove MAC from BGP. */
-       zvni_mac_send_del_to_client(zvni->vni, macaddr, mac->flags);
+       zvni_mac_send_del_to_client(zvni->vni, macaddr);
 
        /*
         * If there are no neigh associated with the mac delete the mac