Merge pull request #8603 from Fredi-raspall/pr_tilfa_link_fallback

Pr tilfa link fallback

doc/user/isisd.rst

@@ -261,10 +261,11 @@ ISIS interface
 
    Limit Remote LFA PQ node selection within the specified metric.
 
-.. clicmd:: isis fast-reroute ti-lfa [level-1|level-2] [node-protection]
+.. clicmd:: isis fast-reroute ti-lfa [level-1|level-2] [node-protection [link-fallback]]
 
    Enable per-prefix TI-LFA fast reroute link or node protection.
-
+   When node protection is used, option link-fallback enables the computation and use of
+   link-protecting LFAs for destinations unprotected by node protection.
 
 .. _showing-isis-information:
 

isisd/isis_circuit.h

@@ -152,6 +152,7 @@ struct isis_circuit {
 	struct hash *lfa_excluded_ifaces[ISIS_LEVELS];
 	bool tilfa_protection[ISIS_LEVELS];
 	bool tilfa_node_protection[ISIS_LEVELS];
+	bool tilfa_link_fallback[ISIS_LEVELS];
 	/*
 	 * Counters as in 10589--11.2.5.9
 	 */

isisd/isis_cli.c

@@ -2647,6 +2647,7 @@ void cli_show_ip_isis_frr(struct vty *vty, struct lyd_node *dnode,
 {
 	bool l1_enabled, l2_enabled;
 	bool l1_node_protection, l2_node_protection;
+	bool l1_link_fallback, l2_link_fallback;
 
 	/* Classic LFA */
 	l1_enabled = yang_dnode_get_bool(dnode, "./level-1/lfa/enable");
@@ -2692,13 +2693,21 @@ void cli_show_ip_isis_frr(struct vty *vty, struct lyd_node *dnode,
 		yang_dnode_get_bool(dnode, "./level-1/ti-lfa/node-protection");
 	l2_node_protection =
 		yang_dnode_get_bool(dnode, "./level-2/ti-lfa/node-protection");
+	l1_link_fallback =
+		yang_dnode_get_bool(dnode, "./level-1/ti-lfa/link-fallback");
+	l2_link_fallback =
+		yang_dnode_get_bool(dnode, "./level-2/ti-lfa/link-fallback");
+
 
 	if (l1_enabled || l2_enabled) {
 		if (l1_enabled == l2_enabled
-		    && l1_node_protection == l2_node_protection) {
+		    && l1_node_protection == l2_node_protection
+		    && l1_link_fallback == l2_link_fallback) {
 			vty_out(vty, " isis fast-reroute ti-lfa");
 			if (l1_node_protection)
 				vty_out(vty, " node-protection");
+			if (l1_link_fallback)
+				vty_out(vty, " link-fallback");
 			vty_out(vty, "\n");
 		} else {
 			if (l1_enabled) {
@@ -2706,6 +2715,8 @@ void cli_show_ip_isis_frr(struct vty *vty, struct lyd_node *dnode,
 					" isis fast-reroute ti-lfa level-1");
 				if (l1_node_protection)
 					vty_out(vty, " node-protection");
+				if (l1_link_fallback)
+					vty_out(vty, " link-fallback");
 				vty_out(vty, "\n");
 			}
 			if (l2_enabled) {
@@ -2713,6 +2724,8 @@ void cli_show_ip_isis_frr(struct vty *vty, struct lyd_node *dnode,
 					" isis fast-reroute ti-lfa level-2");
 				if (l2_node_protection)
 					vty_out(vty, " node-protection");
+				if (l2_link_fallback)
+					vty_out(vty, " link-fallback");
 				vty_out(vty, "\n");
 			}
 		}
@@ -2917,14 +2930,15 @@ void cli_show_frr_remote_lfa_max_metric(struct vty *vty, struct lyd_node *dnode,
  * XPath: /frr-interface:lib/interface/frr-isisd:isis/fast-reroute/level-{1,2}/ti-lfa/enable
  */
 DEFPY(isis_ti_lfa, isis_ti_lfa_cmd,
-      "[no] isis fast-reroute ti-lfa [level-1|level-2]$level [node-protection$node_protection]",
+      "[no] isis fast-reroute ti-lfa [level-1|level-2]$level [node-protection$node_protection [link-fallback$link_fallback]]",
       NO_STR
       "IS-IS routing protocol\n"
       "Interface IP Fast-reroute configuration\n"
       "Enable TI-LFA computation\n"
       "Enable TI-LFA computation for Level 1 only\n"
       "Enable TI-LFA computation for Level 2 only\n"
-      "Protect against node failures\n")
+      "Protect against node failures\n"
+      "Enable link-protection fallback\n")
 {
 	if (!level || strmatch(level, "level-1")) {
 		if (no) {
@@ -2936,6 +2950,10 @@ DEFPY(isis_ti_lfa, isis_ti_lfa_cmd,
 				vty,
 				"./frr-isisd:isis/fast-reroute/level-1/ti-lfa/node-protection",
 				NB_OP_MODIFY, "false");
+			nb_cli_enqueue_change(
+				vty,
+				"./frr-isisd:isis/fast-reroute/level-1/ti-lfa/link-fallback",
+				NB_OP_MODIFY, "false");
 		} else {
 			nb_cli_enqueue_change(
 				vty,
@@ -2946,6 +2964,10 @@ DEFPY(isis_ti_lfa, isis_ti_lfa_cmd,
 				"./frr-isisd:isis/fast-reroute/level-1/ti-lfa/node-protection",
 				NB_OP_MODIFY,
 				node_protection ? "true" : "false");
+			nb_cli_enqueue_change(
+				vty,
+				"./frr-isisd:isis/fast-reroute/level-1/ti-lfa/link-fallback",
+				NB_OP_MODIFY, link_fallback ? "true" : "false");
 		}
 	}
 	if (!level || strmatch(level, "level-2")) {
@@ -2958,6 +2980,10 @@ DEFPY(isis_ti_lfa, isis_ti_lfa_cmd,
 				vty,
 				"./frr-isisd:isis/fast-reroute/level-2/ti-lfa/node-protection",
 				NB_OP_MODIFY, "false");
+			nb_cli_enqueue_change(
+				vty,
+				"./frr-isisd:isis/fast-reroute/level-2/ti-lfa/link-fallback",
+				NB_OP_MODIFY, "false");
 		} else {
 			nb_cli_enqueue_change(
 				vty,
@@ -2968,6 +2994,10 @@ DEFPY(isis_ti_lfa, isis_ti_lfa_cmd,
 				"./frr-isisd:isis/fast-reroute/level-2/ti-lfa/node-protection",
 				NB_OP_MODIFY,
 				node_protection ? "true" : "false");
+			nb_cli_enqueue_change(
+				vty,
+				"./frr-isisd:isis/fast-reroute/level-2/ti-lfa/link-fallback",
+				NB_OP_MODIFY, link_fallback ? "true" : "false");
 		}
 	}
 

isisd/isis_lfa.c

@@ -2258,6 +2258,11 @@ static void isis_spf_run_tilfa(struct isis_area *area,
 		spftree_pc_node = isis_tilfa_compute(area, spftree,
 						     spftree_reverse, resource);
 		isis_spftree_del(spftree_pc_node);
+
+		/* don't do link protection unless link-fallback is configured
+		 */
+		if (!circuit->tilfa_link_fallback[spftree->level - 1])
+			return;
 	}
 
 	/* Compute link protecting repair paths. */

isisd/isis_nb.c

@@ -977,6 +977,12 @@ const struct frr_yang_module_info frr_isisd_info = {
 				.modify = lib_interface_isis_fast_reroute_level_1_ti_lfa_node_protection_modify,
 			}
 		},
+		{
+			.xpath = "/frr-interface:lib/interface/frr-isisd:isis/fast-reroute/level-1/ti-lfa/link-fallback",
+			.cbs = {
+				.modify = lib_interface_isis_fast_reroute_level_1_ti_lfa_link_fallback_modify,
+			}
+		},
 		{
 			.xpath = "/frr-interface:lib/interface/frr-isisd:isis/fast-reroute/level-2/lfa/enable",
 			.cbs = {
@@ -1017,6 +1023,12 @@ const struct frr_yang_module_info frr_isisd_info = {
 				.modify = lib_interface_isis_fast_reroute_level_2_ti_lfa_node_protection_modify,
 			}
 		},
+		{
+			.xpath = "/frr-interface:lib/interface/frr-isisd:isis/fast-reroute/level-2/ti-lfa/link-fallback",
+			.cbs = {
+				.modify = lib_interface_isis_fast_reroute_level_2_ti_lfa_link_fallback_modify,
+			}
+		},
 		{
 			.xpath = "/frr-interface:lib/interface/state/frr-isisd:isis",
 			.cbs = {

isisd/isis_nb.h

@@ -319,6 +319,8 @@ int lib_interface_isis_fast_reroute_level_1_ti_lfa_enable_modify(
 	struct nb_cb_modify_args *args);
 int lib_interface_isis_fast_reroute_level_1_ti_lfa_node_protection_modify(
 	struct nb_cb_modify_args *args);
+int lib_interface_isis_fast_reroute_level_1_ti_lfa_link_fallback_modify(
+	struct nb_cb_modify_args *args);
 int lib_interface_isis_fast_reroute_level_2_lfa_enable_modify(
 	struct nb_cb_modify_args *args);
 int lib_interface_isis_fast_reroute_level_2_lfa_exclude_interface_create(
@@ -335,6 +337,8 @@ int lib_interface_isis_fast_reroute_level_2_ti_lfa_enable_modify(
 	struct nb_cb_modify_args *args);
 int lib_interface_isis_fast_reroute_level_2_ti_lfa_node_protection_modify(
 	struct nb_cb_modify_args *args);
+int lib_interface_isis_fast_reroute_level_2_ti_lfa_link_fallback_modify(
+	struct nb_cb_modify_args *args);
 struct yang_data *
 lib_interface_state_isis_get_elem(struct nb_cb_get_elem_args *args);
 const void *lib_interface_state_isis_adjacencies_adjacency_get_next(

isisd/isis_nb_config.c

@@ -3516,6 +3516,30 @@ int lib_interface_isis_fast_reroute_level_1_ti_lfa_node_protection_modify(
 	return NB_OK;
 }
 
+/*
+ * XPath:
+ * /frr-interface:lib/interface/frr-isisd:isis/fast-reroute/level-1/ti-lfa/link-fallback
+ */
+int lib_interface_isis_fast_reroute_level_1_ti_lfa_link_fallback_modify(
+	struct nb_cb_modify_args *args)
+{
+	struct isis_area *area;
+	struct isis_circuit *circuit;
+
+	if (args->event != NB_EV_APPLY)
+		return NB_OK;
+
+	circuit = nb_running_get_entry(args->dnode, NULL, true);
+	circuit->tilfa_link_fallback[0] =
+		yang_dnode_get_bool(args->dnode, NULL);
+
+	area = circuit->area;
+	if (area)
+		lsp_regenerate_schedule(area, area->is_type, 0);
+
+	return NB_OK;
+}
+
 /*
  * XPath:
  * /frr-interface:lib/interface/frr-isisd:isis/fast-reroute/level-2/lfa/enable
@@ -3720,3 +3744,27 @@ int lib_interface_isis_fast_reroute_level_2_ti_lfa_node_protection_modify(
 
 	return NB_OK;
 }
+
+/*
+ * XPath:
+ * /frr-interface:lib/interface/frr-isisd:isis/fast-reroute/level-2/ti-lfa/link-fallback
+ */
+int lib_interface_isis_fast_reroute_level_2_ti_lfa_link_fallback_modify(
+	struct nb_cb_modify_args *args)
+{
+	struct isis_area *area;
+	struct isis_circuit *circuit;
+
+	if (args->event != NB_EV_APPLY)
+		return NB_OK;
+
+	circuit = nb_running_get_entry(args->dnode, NULL, true);
+	circuit->tilfa_link_fallback[1] =
+		yang_dnode_get_bool(args->dnode, NULL);
+
+	area = circuit->area;
+	if (area)
+		lsp_regenerate_schedule(area, area->is_type, 0);
+
+	return NB_OK;
+}

yang/frr-isisd.yang

@@ -493,6 +493,13 @@ module frr-isisd {
         description
           "Node protection is provided by the alternate.";
       }
+      leaf link-fallback {
+        type boolean;
+        must ". = 'false' or ../enable = 'true'";
+        default false;
+        description
+          "Fallback to link protection.";
+      }
     }
   }