bgpd: backpressure - Add a typesafe list for Zebra Announcement

Modify the bgp master to hold a type safe list for bgp_dests that need
to be passed to zebra.

Future commits will use this.

Ticket: #3390099

Signed-off-by: Donald Sharp <sharpd@nvidia.com>
Signed-off-by: Rajasekar Raja <rajasekarr@nvidia.com>

Author: donaldsharp

bgpd/bgp_main.c

@@ -207,6 +207,8 @@ static __attribute__((__noreturn__)) void bgp_exit(int status)
 	bgp_evpn_mh_finish();
 	bgp_nhg_finish();
 
+	zebra_announce_fini(&bm->zebra_announce_head);
+
 	/* reverse bgp_dump_init */
 	bgp_dump_finish();
 

bgpd/bgp_table.h

@@ -76,6 +76,8 @@ struct bgp_dest {
 
 	STAILQ_ENTRY(bgp_dest) pq;
 
+	struct zebra_announce_item zai;
+
 	uint64_t version;
 
 	mpls_label_t local_label;
@@ -97,6 +99,8 @@ struct bgp_dest {
 	enum bgp_path_selection_reason reason;
 };
 
+DECLARE_LIST(zebra_announce, struct bgp_dest, zai);
+
 extern void bgp_delete_listnode(struct bgp_dest *dest);
 /*
  * bgp_table_iter_t

bgpd/bgpd.c

@@ -8289,6 +8289,8 @@ void bgp_master_init(struct event_loop *master, const int buffer_size,
 	memset(&bgp_master, 0, sizeof(bgp_master));
 
 	bm = &bgp_master;
+
+	zebra_announce_init(&bm->zebra_announce_head);
 	bm->bgp = list_new();
 	bm->listen_sockets = list_new();
 	bm->port = BGP_PORT_DEFAULT;

bgpd/bgpd.h

@@ -18,6 +18,8 @@
 #include "iana_afi.h"
 #include "asn.h"
 
+PREDECL_LIST(zebra_announce);
+
 /* For union sockunion.  */
 #include "queue.h"
 #include "sockunion.h"
@@ -175,6 +177,9 @@ struct bgp_master {
 
 	bool v6_with_v4_nexthops;
 
+	/* To preserve ordering of installations into zebra across all Vrfs */
+	struct zebra_announce_head zebra_announce_head;
+
 	QOBJ_FIELDS;
 };
 DECLARE_QOBJ_TYPE(bgp_master);