zebra: Add helpers to notify locator add/delete

In this commit, we add two helper functions
`zebra_notify_srv6_locator_add` and `zebra_notify_srv6_locator_delete`.
These functions are used to notify locator additions/deletions to
zclients.

Signed-off-by: Carmine Scarpitta <carmine.scarpitta@uniroma2.it>

1 files changed, 52 insertions, 0 deletions

diff --git a/zebra/zebra_srv6.c b/zebra/zebra_srv6.c
index 36506cacc..d61e4f804 100644
--- a/zebra/zebra_srv6.c
+++ b/zebra/zebra_srv6.c
@@ -177,6 +177,58 @@ struct srv6_locator *zebra_srv6_locator_lookup(const char *name)
 	return NULL;
 }
 
+void zebra_notify_srv6_locator_add(struct srv6_locator *locator)
+{
+	struct listnode *node;
+	struct zserv *client;
+
+	/*
+	 * Notify new locator info to zclients.
+	 *
+	 * The srv6 locators and their prefixes are managed by zserv(zebra).
+	 * And an actual configuration the srv6 sid in the srv6 locator is done
+	 * by zclient(bgpd, isisd, etc). The configuration of each locator
+	 * allocation and specify it by zserv and zclient should be
+	 * asynchronous. For that, zclient should be received the event via
+	 * ZAPI when a srv6 locator is added on zebra.
+	 * Basically, in SRv6, adding/removing SRv6 locators is performed less
+	 * frequently than adding rib entries, so a broad to all zclients will
+	 * not degrade the overall performance of FRRouting.
+	 */
+	for (ALL_LIST_ELEMENTS_RO(zrouter.client_list, node, client))
+		zsend_zebra_srv6_locator_add(client, locator);
+}
+
+void zebra_notify_srv6_locator_delete(struct srv6_locator *locator)
+{
+	struct listnode *n;
+	struct srv6_locator_chunk *c;
+	struct zserv *client;
+
+	/*
+	 * Notify deleted locator info to zclients if needed.
+	 *
+	 * zclient(bgpd,isisd,etc) allocates a sid from srv6 locator chunk and
+	 * uses it for its own purpose. For example, in the case of BGP L3VPN,
+	 * the SID assigned to vpn unicast rib will be given.
+	 * And when the locator is deleted by zserv(zebra), those SIDs need to
+	 * be withdrawn. The zclient must initiate the withdrawal of the SIDs
+	 * by ZEBRA_SRV6_LOCATOR_DELETE, and this notification is sent to the
+	 * owner of each chunk.
+	 */
+	for (ALL_LIST_ELEMENTS_RO((struct list *)locator->chunks, n, c)) {
+		if (c->proto == ZEBRA_ROUTE_SYSTEM)
+			continue;
+		client = zserv_find_client(c->proto, c->instance);
+		if (!client) {
+			zlog_warn("Not found zclient(proto=%u, instance=%u).",
+				  c->proto, c->instance);
+			continue;
+		}
+		zsend_zebra_srv6_locator_delete(client, locator);
+	}
+}
+
 struct zebra_srv6 *zebra_srv6_get_default(void)
 {
 	static struct zebra_srv6 srv6;