From f5ca329b2d5a2f19b583b7732950256c788db34c Mon Sep 17 00:00:00 2001
From: Hiroki Shirokura <slank.dev@gmail.com>
Date: Sun, 5 Sep 2021 10:05:53 +0000
Subject: [PATCH] zebra: implement srv6 locator add/delete notification via
 ZAPI

Signed-off-by: Hiroki Shirokura <slank.dev@gmail.com>
---
 zebra/zapi_msg.c   | 25 +++++++++++++++++++++++++
 zebra/zebra_srv6.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 70 insertions(+)

diff --git a/zebra/zapi_msg.c b/zebra/zapi_msg.c
index 6666b3525e..07d171b58f 100644
--- a/zebra/zapi_msg.c
+++ b/zebra/zapi_msg.c
@@ -1137,6 +1137,31 @@ static int zsend_table_manager_connect_response(struct zserv *client,
 	return zserv_send_message(client, s);
 }
 
+/* SRv6 locator add notification from zebra daemon. */
+int zsend_zebra_srv6_locator_add(struct zserv *client, struct srv6_locator *loc)
+{
+	struct stream *s = stream_new(ZEBRA_MAX_PACKET_SIZ);
+
+	zclient_create_header(s, ZEBRA_SRV6_LOCATOR_ADD, VRF_DEFAULT);
+	zapi_srv6_locator_encode(s, loc);
+	stream_putw_at(s, 0, stream_get_endp(s));
+
+	return zserv_send_message(client, s);
+}
+
+/* SRv6 locator delete notification from zebra daemon. */
+int zsend_zebra_srv6_locator_delete(struct zserv *client,
+				    struct srv6_locator *loc)
+{
+	struct stream *s = stream_new(ZEBRA_MAX_PACKET_SIZ);
+
+	zclient_create_header(s, ZEBRA_SRV6_LOCATOR_DELETE, VRF_DEFAULT);
+	zapi_srv6_locator_encode(s, loc);
+	stream_putw_at(s, 0, stream_get_endp(s));
+
+	return zserv_send_message(client, s);
+}
+
 /* Inbound message handling ------------------------------------------------ */
 
 const int cmd2type[] = {
diff --git a/zebra/zebra_srv6.c b/zebra/zebra_srv6.c
index b11331a180..ad99ae1786 100644
--- a/zebra/zebra_srv6.c
+++ b/zebra/zebra_srv6.c
@@ -106,15 +106,60 @@ void zebra_srv6_locator_add(struct srv6_locator *locator)
 {
 	struct zebra_srv6 *srv6 = zebra_srv6_get_default();
 	struct srv6_locator *tmp;
+	struct listnode *node;
+	struct zserv *client;
 
 	tmp = zebra_srv6_locator_lookup(locator->name);
 	if (!tmp)
 		listnode_add(srv6->locators, locator);
+
+	/*
+	 * 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_srv6_locator_delete(struct srv6_locator *locator)
 {
+	struct listnode *n;
+	struct srv6_locator_chunk *c;
 	struct zebra_srv6 *srv6 = zebra_srv6_get_default();
+	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(
+				"%s: Not found zclient(proto=%u, instance=%u).",
+				__func__, c->proto, c->instance);
+			continue;
+		}
+		zsend_zebra_srv6_locator_delete(client, locator);
+	}
 
 	listnode_delete(srv6->locators, locator);
 }