zebra: Repond to GET_LOCATOR ZAPI request

The previous commits introduced a new operation,
`ZEBRA_SRV6_MANAGER_GET_LOCATOR`, allowing a daemon to request
information about a specific SRv6 locator from the SRv6 SID Manager.

This commit extends the SID Manager to respond to a
`ZEBRA_SRV6_MANAGER_GET_LOCATOR` request and provide the requested
locator information.

Signed-off-by: Carmine Scarpitta <cscarpit@cisco.com>

zebra/zapi_msg.c

@@ -3006,6 +3006,31 @@ stream_failure:
 	return;
 }
 
+/**
+ * Handle SRv6 locator get request received from a client daemon protocol.
+ *
+ * @param client The client zapi session
+ * @param msg The request message
+ */
+static void zread_srv6_manager_get_locator(struct zserv *client,
+					   struct stream *msg)
+{
+	struct stream *s = msg;
+	uint16_t len;
+	char locator_name[SRV6_LOCNAME_SIZE] = { 0 };
+	struct srv6_locator *locator = NULL;
+
+	/* Get data */
+	STREAM_GETW(s, len);
+	STREAM_GET(locator_name, s, len);
+
+	/* Call hook to get the locator info using wrapper */
+	srv6_manager_get_locator_call(&locator, client, locator_name);
+
+stream_failure:
+	return;
+}
+
 static void zread_srv6_manager_request(ZAPI_HANDLER_ARGS)
 {
 	switch (hdr->command) {
@@ -3017,6 +3042,9 @@ static void zread_srv6_manager_request(ZAPI_HANDLER_ARGS)
 		zread_srv6_manager_release_locator_chunk(client, msg,
 							 zvrf_id(zvrf));
 		break;
+	case ZEBRA_SRV6_MANAGER_GET_LOCATOR:
+		zread_srv6_manager_get_locator(client, msg);
+		break;
 	default:
 		zlog_err("%s: unknown SRv6 Manager command", __func__);
 		break;
@@ -3965,6 +3993,7 @@ void (*const zserv_handlers[])(ZAPI_HANDLER_ARGS) = {
 	[ZEBRA_MLAG_FORWARD_MSG] = zebra_mlag_forward_client_msg,
 	[ZEBRA_SRV6_MANAGER_GET_LOCATOR_CHUNK] = zread_srv6_manager_request,
 	[ZEBRA_SRV6_MANAGER_RELEASE_LOCATOR_CHUNK] = zread_srv6_manager_request,
+	[ZEBRA_SRV6_MANAGER_GET_LOCATOR] = zread_srv6_manager_request,
 	[ZEBRA_CLIENT_CAPABILITIES] = zread_client_capabilities,
 	[ZEBRA_NEIGH_DISCOVER] = zread_neigh_discover,
 	[ZEBRA_NHG_ADD] = zread_nhg_add,

zebra/zapi_msg.h

@@ -110,6 +110,9 @@ extern int zsend_zebra_srv6_locator_delete(struct zserv *client,
 extern int zsend_srv6_manager_get_locator_chunk_response(struct zserv *client,
 		vrf_id_t vrf_id, struct srv6_locator *loc);
 
+extern int zsend_srv6_manager_get_locator_response(struct zserv *client,
+						   struct srv6_locator *locator);
+
 #ifdef __cplusplus
 }
 #endif

zebra/zebra_srv6.c

@@ -61,6 +61,11 @@ DEFINE_HOOK(srv6_manager_release_chunk,
 	     vrf_id_t vrf_id),
 	    (client, locator_name, vrf_id));
 
+DEFINE_HOOK(srv6_manager_get_locator,
+	    (struct srv6_locator **locator, struct zserv *client,
+	     const char *locator_name),
+	    (locator, client, locator_name));
+
 /* define wrappers to be called in zapi_msg.c (as hooks must be called in
  * source file where they were defined)
  */
@@ -91,6 +96,13 @@ int srv6_manager_client_disconnect_cb(struct zserv *client)
 	return 0;
 }
 
+void srv6_manager_get_locator_call(struct srv6_locator **locator,
+				   struct zserv *client,
+				   const char *locator_name)
+{
+	hook_call(srv6_manager_get_locator, locator, client, locator_name);
+}
+
 static int zebra_srv6_cleanup(struct zserv *client)
 {
 	return 0;
@@ -921,6 +933,28 @@ void zebra_srv6_encap_src_addr_unset(void)
 	memset(&srv6->encap_src_addr, 0, sizeof(struct in6_addr));
 }
 
+/**
+ * Handle a get SRv6 Locator request received from a client.
+ *
+ * It looks up the requested locator and send it to the client.
+ *
+ * @param locator SRv6 locator returned by this function
+ * @param client The client that sent the Get SRv6 Locator request
+ * @param locator_name Name of the locator to look up
+ *
+ * @return 0 on success
+ */
+static int srv6_manager_get_srv6_locator_internal(struct srv6_locator **locator,
+						  struct zserv *client,
+						  const char *locator_name)
+{
+	*locator = zebra_srv6_locator_lookup(locator_name);
+	if (!*locator)
+		return -1;
+
+	return zsend_zebra_srv6_locator_add(client, *locator);
+}
+
 void zebra_srv6_terminate(void)
 {
 	struct srv6_locator *locator;
@@ -983,6 +1017,9 @@ void zebra_srv6_init(void)
 		      zebra_srv6_manager_get_locator_chunk);
 	hook_register(srv6_manager_release_chunk,
 		      zebra_srv6_manager_release_locator_chunk);
+
+	hook_register(srv6_manager_get_locator,
+		      srv6_manager_get_srv6_locator_internal);
 }
 
 bool zebra_srv6_is_enable(void)

zebra/zebra_srv6.h

@@ -231,6 +231,10 @@ DECLARE_HOOK(srv6_manager_release_chunk,
 	      vrf_id_t vrf_id),
 	     (client, locator_name, vrf_id));
 
+DECLARE_HOOK(srv6_manager_get_locator,
+	     (struct srv6_locator **locator, struct zserv *client,
+	      const char *locator_name),
+	     (locator, client, locator_name));
 
 extern void zebra_srv6_locator_add(struct srv6_locator *locator);
 extern void zebra_srv6_locator_delete(struct srv6_locator *locator);
@@ -286,6 +290,10 @@ zebra_srv6_sid_alloc(struct zebra_srv6_sid_ctx *ctx, struct in6_addr *sid_value,
 extern void zebra_srv6_sid_free(struct zebra_srv6_sid *sid);
 extern void delete_zebra_srv6_sid(void *val);
 
+extern void srv6_manager_get_locator_call(struct srv6_locator **locator,
+					  struct zserv *client,
+					  const char *locator_name);
+
 extern struct zebra_srv6_sid_ctx *zebra_srv6_sid_ctx_alloc(void);
 extern void zebra_srv6_sid_ctx_free(struct zebra_srv6_sid_ctx *ctx);
 extern void delete_zebra_srv6_sid_ctx(void *val);