zebra: separate zebra_vrf_lookup_table_with_id()

We were creating `other` tables in rib_del(), vty commands, and
dataplane return callback via the zebra_vrf_table_with_table_id()
API.

Seperate the API into only a lookup, never create
and added another with `get` in the name (following the standard
we use in other table APIs).

Then changed the rib_del(), rib_find_rn_from_ctx(), and show route
summary vty command to use the lookup API instead.

This was found via a crash where two different vrfs though they owned
the table. On delete, one free'd all the nodes, and then the other tried
to use them. It required specific timing of a VRF existing, going away,
and coming back again to cause the crash.

=23464== Invalid read of size 8
==23464==    at 0x179EA4: rib_dest_from_rnode (rib.h:433)
==23464==    by 0x17ACB1: zebra_vrf_delete (zebra_vrf.c:253)
==23464==    by 0x48F3D45: vrf_delete (vrf.c:243)
==23464==    by 0x48F4468: vrf_terminate (vrf.c:532)
==23464==    by 0x13D8C5: sigint (main.c:172)
==23464==    by 0x48DD25C: quagga_sigevent_process (sigevent.c:105)
==23464==    by 0x48F0502: thread_fetch (thread.c:1417)
==23464==    by 0x48AC82B: frr_run (libfrr.c:1023)
==23464==    by 0x13DD02: main (main.c:483)
==23464==  Address 0x5152788 is 104 bytes inside a block of size 112 free'd
==23464==    at 0x48369AB: free (in /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so)
==23464==    by 0x48B25B8: qfree (memory.c:129)
==23464==    by 0x48EA335: route_node_destroy (table.c:500)
==23464==    by 0x48E967F: route_node_free (table.c:90)
==23464==    by 0x48E9742: route_table_free (table.c:124)
==23464==    by 0x48E9599: route_table_finish (table.c:60)
==23464==    by 0x170CEA: zebra_router_free_table (zebra_router.c:165)
==23464==    by 0x170DB4: zebra_router_release_table (zebra_router.c:188)
==23464==    by 0x17AAD2: zebra_vrf_disable (zebra_vrf.c:222)
==23464==    by 0x48F3F0C: vrf_disable (vrf.c:313)
==23464==    by 0x48F3CCF: vrf_delete (vrf.c:223)
==23464==    by 0x48F4468: vrf_terminate (vrf.c:532)
==23464==  Block was alloc'd at
==23464==    at 0x4837B65: calloc (in /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so)
==23464==    by 0x48B24A2: qcalloc (memory.c:110)
==23464==    by 0x48EA2FE: route_node_create (table.c:488)
==23464==    by 0x48E95C7: route_node_new (table.c:66)
==23464==    by 0x48E95E5: route_node_set (table.c:75)
==23464==    by 0x48E9EA9: route_node_get (table.c:326)
==23464==    by 0x48E1EDB: srcdest_rnode_get (srcdest_table.c:244)
==23464==    by 0x16EA4B: rib_add_multipath (zebra_rib.c:2730)
==23464==    by 0x1A5310: zread_route_add (zapi_msg.c:1592)
==23464==    by 0x1A7B8E: zserv_handle_commands (zapi_msg.c:2579)
==23464==    by 0x19D689: zserv_process_messages (zserv.c:523)
==23464==    by 0x48F09F8: thread_call (thread.c:1599)

Signed-off-by: Stephen Worley <sworley@cumulusnetworks.com>

5 files changed, 46 insertions, 24 deletions

diff --git a/zebra/redistribute.c b/zebra/redistribute.c
index 4e0163f8ac..98603c9693 100644
--- a/zebra/redistribute.c
+++ b/zebra/redistribute.c
@@ -718,8 +718,8 @@ int zebra_import_table(afi_t afi, vrf_id_t vrf_id, uint32_t table_id,
 	if (afi >= AFI_MAX)
 		return (-1);
 
-	table = zebra_vrf_table_with_table_id(afi, SAFI_UNICAST, vrf_id,
-					      table_id);
+	table = zebra_vrf_get_table_with_table_id(afi, SAFI_UNICAST, vrf_id,
+						  table_id);
 	if (table == NULL) {
 		return 0;
 	} else if (IS_ZEBRA_DEBUG_RIB) {
@@ -830,8 +830,8 @@ static void zebra_import_table_rm_update_vrf_afi(struct zebra_vrf *zvrf,
 	if ((!rmap_name) || (strcmp(rmap_name, rmap) != 0))
 		return;
 
-	table = zebra_vrf_table_with_table_id(afi, SAFI_UNICAST,
-					      zvrf->vrf->vrf_id, table_id);
+	table = zebra_vrf_get_table_with_table_id(afi, SAFI_UNICAST,
+						  zvrf->vrf->vrf_id, table_id);
 	if (!table) {
 		if (IS_ZEBRA_DEBUG_RIB_DETAILED)
 			zlog_debug("%s: Table id=%d not found", __func__,
diff --git a/zebra/zebra_rib.c b/zebra/zebra_rib.c
index e0bf1a58f2..c24a518afb 100644
--- a/zebra/zebra_rib.c
+++ b/zebra/zebra_rib.c
@@ -1575,10 +1575,9 @@ rib_find_rn_from_ctx(const struct zebra_dplane_ctx *ctx)
 
 	/* Locate rn and re(s) from ctx */
 
-	table = zebra_vrf_table_with_table_id(dplane_ctx_get_afi(ctx),
-					      dplane_ctx_get_safi(ctx),
-					      dplane_ctx_get_vrf(ctx),
-					      dplane_ctx_get_table(ctx));
+	table = zebra_vrf_lookup_table_with_table_id(
+		dplane_ctx_get_afi(ctx), dplane_ctx_get_safi(ctx),
+		dplane_ctx_get_vrf(ctx), dplane_ctx_get_table(ctx));
 	if (table == NULL) {
 		if (IS_ZEBRA_DEBUG_DPLANE) {
 			zlog_debug("Failed to find route for ctx: no table for afi %d, safi %d, vrf %u",
@@ -2664,7 +2663,8 @@ int rib_add_multipath(afi_t afi, safi_t safi, struct prefix *p,
 	assert(!src_p || !src_p->prefixlen || afi == AFI_IP6);
 
 	/* Lookup table.  */
-	table = zebra_vrf_table_with_table_id(afi, safi, re->vrf_id, re->table);
+	table = zebra_vrf_get_table_with_table_id(afi, safi, re->vrf_id,
+						  re->table);
 	if (!table) {
 		if (re->ng)
 			nexthop_group_delete(&re->ng);
@@ -2809,7 +2809,8 @@ void rib_delete(afi_t afi, safi_t safi, vrf_id_t vrf_id, int type,
 	assert(!src_p || !src_p->prefixlen || afi == AFI_IP6);
 
 	/* Lookup table.  */
-	table = zebra_vrf_table_with_table_id(afi, safi, vrf_id, table_id);
+	table = zebra_vrf_lookup_table_with_table_id(afi, safi, vrf_id,
+						     table_id);
 	if (!table)
 		return;
 
diff --git a/zebra/zebra_vrf.c b/zebra/zebra_vrf.c
index f425c0e49e..c392303760 100644
--- a/zebra/zebra_vrf.c
+++ b/zebra/zebra_vrf.c
@@ -343,13 +343,12 @@ int zebra_vrf_has_config(struct zebra_vrf *zvrf)
  * - case VRF backend is default : on default VRF only
  * - case VRF backend is netns : on all VRFs
  */
-struct route_table *zebra_vrf_table_with_table_id(afi_t afi, safi_t safi,
-						  vrf_id_t vrf_id,
-						  uint32_t table_id)
+struct route_table *zebra_vrf_lookup_table_with_table_id(afi_t afi, safi_t safi,
+							 vrf_id_t vrf_id,
+							 uint32_t table_id)
 {
 	struct zebra_vrf *zvrf = vrf_info_lookup(vrf_id);
 	struct other_route_table ort, *otable;
-	struct route_table *table;
 
 	if (!zvrf)
 		return NULL;
@@ -364,9 +363,28 @@ struct route_table *zebra_vrf_table_with_table_id(afi_t afi, safi_t safi,
 	ort.safi = safi;
 	ort.table_id = table_id;
 	otable = otable_find(&zvrf->other_tables, &ort);
+
 	if (otable)
 		return otable->table;
 
+	return NULL;
+}
+
+struct route_table *zebra_vrf_get_table_with_table_id(afi_t afi, safi_t safi,
+						      vrf_id_t vrf_id,
+						      uint32_t table_id)
+{
+	struct zebra_vrf *zvrf = vrf_info_lookup(vrf_id);
+	struct other_route_table *otable;
+	struct route_table *table;
+
+	table = zebra_vrf_lookup_table_with_table_id(afi, safi, vrf_id,
+						     table_id);
+
+	if (table)
+		goto done;
+
+	/* Create it as an `other` table */
 	table = zebra_router_get_table(zvrf, table_id, afi, safi);
 
 	otable = XCALLOC(MTYPE_OTHER_TABLE, sizeof(*otable));
@@ -376,6 +394,7 @@ struct route_table *zebra_vrf_table_with_table_id(afi_t afi, safi_t safi,
 	otable->table = table;
 	otable_add(&zvrf->other_tables, otable);
 
+done:
 	return table;
 }
 
diff --git a/zebra/zebra_vrf.h b/zebra/zebra_vrf.h
index 6c80f9bcb4..5448e17073 100644
--- a/zebra/zebra_vrf.h
+++ b/zebra/zebra_vrf.h
@@ -233,9 +233,13 @@ zvrf_other_table_compare_func(const struct other_route_table *a,
 DECLARE_RBTREE_UNIQ(otable, struct other_route_table, next,
 		    zvrf_other_table_compare_func)
 
-struct route_table *zebra_vrf_table_with_table_id(afi_t afi, safi_t safi,
-						  vrf_id_t vrf_id,
-						  uint32_t table_id);
+extern struct route_table *
+zebra_vrf_lookup_table_with_table_id(afi_t afi, safi_t safi, vrf_id_t vrf_id,
+				     uint32_t table_id);
+extern struct route_table *zebra_vrf_get_table_with_table_id(afi_t afi,
+							     safi_t safi,
+							     vrf_id_t vrf_id,
+							     uint32_t table_id);
 
 extern void zebra_vrf_update_all(struct zserv *client);
 extern struct zebra_vrf *zebra_vrf_lookup_by_id(vrf_id_t vrf_id);
diff --git a/zebra/zebra_vty.c b/zebra/zebra_vty.c
index 9d17454730..12517f3135 100644
--- a/zebra/zebra_vty.c
+++ b/zebra/zebra_vty.c
@@ -1708,10 +1708,9 @@ DEFPY (show_route_summary,
 			if ((zvrf = vrf->info) == NULL)
 				continue;
 
-			table = zebra_vrf_table_with_table_id(afi,
-							      SAFI_UNICAST,
-							      zvrf->vrf->vrf_id,
-							      table_id);
+			table = zebra_vrf_lookup_table_with_table_id(
+				afi, SAFI_UNICAST, zvrf->vrf->vrf_id, table_id);
+
 			if (!table)
 				continue;
 
@@ -1726,9 +1725,8 @@ DEFPY (show_route_summary,
 		if (vrf_name)
 			VRF_GET_ID(vrf_id, vrf_name, false);
 
-		table = zebra_vrf_table_with_table_id(afi,
-						      SAFI_UNICAST,
-						      vrf_id, table_id);
+		table = zebra_vrf_lookup_table_with_table_id(afi, SAFI_UNICAST,
+							     vrf_id, table_id);
 		if (!table)
 			return CMD_SUCCESS;