zebra: fix crash seen on VxLAN SG table cleanup done as a part of vrf disable

There are two fixes in this commit -
1. Prevent implicit deletion of (*,G) entries during (S,G) cleanup.
This is done by creating a dummy reference on all (*,G) entries.
This is needed for a hash-walk based table cleanup.
2. Free up the SG hash table when the VRF is deleted.

Ticket: CM-30151

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

diff --git a/zebra/zebra_vxlan.c b/zebra/zebra_vxlan.c
index 4b3b142d4024bb804cee1a903edff68b61343310..d039bfe9113114ee57f85397c951066936933b91 100644 (file)
--- a/zebra/zebra_vxlan.c
+++ b/zebra/zebra_vxlan.c
@@ -116,7 +116,7 @@ static void zebra_vxlan_sg_deref(struct in_addr local_vtep_ip,
                                struct in_addr mcast_grp);
 static void zebra_vxlan_sg_ref(struct in_addr local_vtep_ip,
                                struct in_addr mcast_grp);
-static void zebra_vxlan_sg_cleanup(struct hash_bucket *bucket, void *arg);
+static void zebra_vxlan_cleanup_sg_table(struct zebra_vrf *zvrf);
 
 /* Private functions */
 static int host_rb_entry_compare(const struct host_rb_entry *hle1,
@@ -5658,7 +5658,7 @@ void zebra_vxlan_cleanup_tables(struct zebra_vrf *zvrf)
        if (!zvrf)
                return;
        hash_iterate(zvrf->evpn_table, zebra_evpn_vxlan_cleanup_all, zvrf);
-       hash_iterate(zvrf->vxlan_sg_table, zebra_vxlan_sg_cleanup, NULL);
+       zebra_vxlan_cleanup_sg_table(zvrf);
 
        if (zvrf == evpn_zvrf)
                zebra_evpn_es_cleanup();
@@ -5671,6 +5671,11 @@ void zebra_vxlan_close_tables(struct zebra_vrf *zvrf)
                return;
        hash_iterate(zvrf->evpn_table, zebra_evpn_vxlan_cleanup_all, zvrf);
        hash_free(zvrf->evpn_table);
+       if (zvrf->vxlan_sg_table) {
+               zebra_vxlan_cleanup_sg_table(zvrf);
+               hash_free(zvrf->vxlan_sg_table);
+               zvrf->vxlan_sg_table = NULL;
+       }
 }
 
 /* init the l3vni table */
@@ -5919,6 +5924,30 @@ static void zebra_vxlan_sg_ref(struct in_addr local_vtep_ip,
        zebra_vxlan_sg_do_ref(zvrf, local_vtep_ip, mcast_grp);
 }
 
+static void zebra_vxlan_xg_pre_cleanup(struct hash_bucket *backet, void *arg)
+{
+       zebra_vxlan_sg_t *vxlan_sg = (zebra_vxlan_sg_t *)backet->data;
+
+       /* increment the ref count against (*,G) to prevent them from being
+        * deleted
+        */
+       if (vxlan_sg->sg.src.s_addr == INADDR_ANY)
+               ++vxlan_sg->ref_cnt;
+}
+
+static void zebra_vxlan_xg_post_cleanup(struct hash_bucket *backet, void *arg)
+{
+       zebra_vxlan_sg_t *vxlan_sg = (zebra_vxlan_sg_t *)backet->data;
+
+       /* decrement the dummy ref count against (*,G) to delete them */
+       if (vxlan_sg->sg.src.s_addr == INADDR_ANY) {
+               if (vxlan_sg->ref_cnt)
+                       --vxlan_sg->ref_cnt;
+               if (!vxlan_sg->ref_cnt)
+                       zebra_vxlan_sg_del(vxlan_sg);
+       }
+}
+
 static void zebra_vxlan_sg_cleanup(struct hash_bucket *backet, void *arg)
 {
        zebra_vxlan_sg_t *vxlan_sg = (zebra_vxlan_sg_t *)backet->data;
@@ -5926,6 +5955,19 @@ static void zebra_vxlan_sg_cleanup(struct hash_bucket *backet, void *arg)
        zebra_vxlan_sg_del(vxlan_sg);
 }
 
+static void zebra_vxlan_cleanup_sg_table(struct zebra_vrf *zvrf)
+{
+       /* increment the ref count against (*,G) to prevent them from being
+        * deleted
+        */
+       hash_iterate(zvrf->vxlan_sg_table, zebra_vxlan_xg_pre_cleanup, NULL);
+
+       hash_iterate(zvrf->vxlan_sg_table, zebra_vxlan_sg_cleanup, NULL);
+
+       /* decrement the dummy ref count against the XG entries */
+       hash_iterate(zvrf->vxlan_sg_table, zebra_vxlan_xg_post_cleanup, NULL);
+}
+
 static void zebra_vxlan_sg_replay_send(struct hash_bucket *backet, void *arg)
 {
        zebra_vxlan_sg_t *vxlan_sg = (zebra_vxlan_sg_t *)backet->data;