isisd: IS-IS-SR preparation for master 4/5

 * Regroup fonctions to install label for Prefix and Adjacency SID
 * Change 'replace_semantics' variable name by 'make_before_break' in
   sr_prefix_reinstall() function and adjust comments
 * Call directly lsp_regenerate_schedule() from isis_nb_config.c when MSD
   is updated

Signed-off-by: Olivier Dugeon <olivier.dugeon@orange.com>

5 files changed, 83 insertions, 55 deletions

diff --git a/isisd/isis_nb_config.c b/isisd/isis_nb_config.c
index ec3b7baa31..a649e896fa 100644
--- a/isisd/isis_nb_config.c
+++ b/isisd/isis_nb_config.c
@@ -1521,7 +1521,9 @@ int isis_instance_segment_routing_msd_node_msd_modify(
 
 	area = nb_running_get_entry(args->dnode, NULL, true);
 	area->srdb.config.msd = yang_dnode_get_uint8(args->dnode, NULL);
-	isis_sr_cfg_msd_update(area);
+
+	/* Update and regenerate LSP */
+	lsp_regenerate_schedule(area, area->is_type, 0);
 
 	return NB_OK;
 }
@@ -1536,7 +1538,9 @@ int isis_instance_segment_routing_msd_node_msd_destroy(
 
 	area = nb_running_get_entry(args->dnode, NULL, true);
 	area->srdb.config.msd = 0;
-	isis_sr_cfg_msd_update(area);
+
+	/* Update and regenerate LSP */
+	lsp_regenerate_schedule(area, area->is_type, 0);
 
 	return NB_OK;
 }
diff --git a/isisd/isis_sr.c b/isisd/isis_sr.c
index 948b8e39c8..fc97c0fc98 100644
--- a/isisd/isis_sr.c
+++ b/isisd/isis_sr.c
@@ -51,8 +51,7 @@
 DEFINE_MTYPE_STATIC(ISISD, ISIS_SR_INFO, "ISIS segment routing information")
 
 static void sr_prefix_uninstall(struct sr_prefix *srp);
-static void sr_prefix_reinstall(struct sr_prefix *srp,
-				     bool replace_semantics);
+static void sr_prefix_reinstall(struct sr_prefix *srp, bool make_before_break);
 
 /*----------------------------------------------------------------------------*/
 
@@ -138,12 +137,6 @@ int isis_sr_cfg_srgb_update(struct isis_area *area, uint32_t lower_bound,
 	return 0;
 }
 
-/* Handle changes in the local MSD configuration. */
-void isis_sr_cfg_msd_update(struct isis_area *area)
-{
-	lsp_regenerate_schedule(area, area->is_type, 0);
-}
-
 /* Handle new Prefix-SID configuration. */
 struct sr_prefix_cfg *isis_sr_cfg_prefix_add(struct isis_area *area,
 					     const struct prefix *prefix)
@@ -368,8 +361,10 @@ static void sr_node_srgb_update(struct isis_area *area, int level,
 				continue;
 
 			/*
-			 * Reinstall all Prefix-SID nexthops using route replace
-			 * semantics.
+			 * The Prefix-SID input label hasn't changed. We could
+			 * re-install all Prefix-SID with "Make Before Break"
+			 * option. Zebra layer will update output label(s) by
+			 * adding new entry before removing the old one(s).
 			 */
 			sr_prefix_reinstall(srp, true);
 			break;
@@ -506,7 +501,7 @@ static int sr_prefix_install_local(struct sr_prefix *srp)
 	isis_sr_nexthop_update(&srp->u.local.info, MPLS_LABEL_IMPLICIT_NULL);
 
 	/* Install Prefix-SID in the forwarding plane. */
-	isis_zebra_install_prefix_sid(srp);
+	isis_zebra_send_prefix_sid(ZEBRA_MPLS_LABELS_REPLACE, srp);
 
 	return 0;
 }
@@ -587,7 +582,7 @@ static int sr_prefix_install_remote(struct sr_prefix *srp)
 	srp->input_label = input_label;
 
 	/* Install Prefix-SID in the forwarding plane. */
-	isis_zebra_install_prefix_sid(srp);
+	isis_zebra_send_prefix_sid(ZEBRA_MPLS_LABELS_REPLACE, srp);
 
 	return 0;
 }
@@ -647,7 +642,7 @@ static void sr_prefix_uninstall(struct sr_prefix *srp)
 		 srp->sid.value);
 
 	/* Uninstall Prefix-SID from the forwarding plane. */
-	isis_zebra_uninstall_prefix_sid(srp);
+	isis_zebra_send_prefix_sid(ZEBRA_MPLS_LABELS_DELETE, srp);
 
 	/* Reset internal state. */
 	srp->input_label = MPLS_INVALID_LABEL;
@@ -666,15 +661,16 @@ static void sr_prefix_uninstall(struct sr_prefix *srp)
 }
 
 /* Reinstall local or remote Prefix-SID. */
-static void sr_prefix_reinstall(struct sr_prefix *srp, bool replace_semantics)
+static inline void sr_prefix_reinstall(struct sr_prefix *srp,
+				       bool make_before_break)
 {
 	/*
-	 * Route replace semantics can be used only when we know for sure that
+	 * Make Before Break can be used only when we know for sure that
 	 * the Prefix-SID input label hasn't changed. Otherwise we need to
 	 * uninstall the Prefix-SID first using the old input label before
 	 * reinstalling it.
 	 */
-	if (!replace_semantics)
+	if (!make_before_break)
 		sr_prefix_uninstall(srp);
 
 	sr_prefix_install(srp);
@@ -960,6 +956,11 @@ static int sr_route_update(struct isis_area *area, struct prefix *prefix,
 		return 0;
 
 	if (CHECK_FLAG(route_info->flag, ISIS_ROUTE_FLAG_ACTIVE)) {
+		/*
+		 * The Prefix-SID input label hasn't changed. We could use the
+		 * "Make Before Break" option. Zebra layer will update output
+		 * label by adding new label(s) before removing old one(s).
+		 */
 		sr_prefix_reinstall(srp, true);
 		srp->u.remote.rinfo = route_info;
 	} else {
@@ -972,36 +973,6 @@ static int sr_route_update(struct isis_area *area, struct prefix *prefix,
 
 /*----------------------------------------------------------------------------*/
 
-/* Install or uninstall (LAN)-Adj-SID. */
-static void sr_adj_sid_install_uninstall(bool install,
-					 const struct sr_adjacency *sra)
-{
-	struct zapi_labels zl;
-	struct zapi_nexthop *znh;
-	int cmd;
-
-	cmd = install ? ZEBRA_MPLS_LABELS_ADD : ZEBRA_MPLS_LABELS_DELETE;
-
-	sr_debug("  |- %s label %u for interface %s",
-		 install ? "Add" : "Delete", sra->nexthop.label,
-		 sra->adj->circuit->interface->name);
-
-	memset(&zl, 0, sizeof(zl));
-	zl.type = ZEBRA_LSP_ISIS_SR;
-	zl.local_label = sra->nexthop.label;
-	zl.nexthop_num = 1;
-	znh = &zl.nexthops[0];
-	znh->gate = sra->nexthop.address;
-	znh->type = (sra->nexthop.family == AF_INET)
-			    ? NEXTHOP_TYPE_IPV4_IFINDEX
-			    : NEXTHOP_TYPE_IPV6_IFINDEX;
-	znh->ifindex = sra->adj->circuit->interface->ifindex;
-	znh->label_num = 1;
-	znh->labels[0] = MPLS_LABEL_IMPLICIT_NULL;
-
-	(void)zebra_send_mpls_labels(zclient, cmd, &zl);
-}
-
 /* Add new local Adj-SID. */
 static void sr_adj_sid_add_single(struct isis_adjacency *adj, int family,
 				  bool backup)
@@ -1082,7 +1053,7 @@ static void sr_adj_sid_add_single(struct isis_adjacency *adj, int family,
 	listnode_add(area->srdb.adj_sids, sra);
 	listnode_add(adj->adj_sids, sra);
 
-	sr_adj_sid_install_uninstall(true, sra);
+	isis_zebra_send_adjacency_sid(ZEBRA_MPLS_LABELS_ADD, sra);
 }
 
 static void sr_adj_sid_add(struct isis_adjacency *adj, int family)
@@ -1099,7 +1070,7 @@ static void sr_adj_sid_del(struct sr_adjacency *sra)
 
 	sr_debug("ISIS-Sr (%s): Delete Adjacency SID", area->area_tag);
 
-	sr_adj_sid_install_uninstall(false, sra);
+	isis_zebra_send_adjacency_sid(ZEBRA_MPLS_LABELS_DELETE, sra);
 
 	switch (circuit->circ_type) {
 	case CIRCUIT_T_BROADCAST:
diff --git a/isisd/isis_sr.h b/isisd/isis_sr.h
index 0b84db90ff..b2e0130754 100644
--- a/isisd/isis_sr.h
+++ b/isisd/isis_sr.h
@@ -240,7 +240,6 @@ struct isis_sr_db {
 /* Prototypes. */
 extern int isis_sr_cfg_srgb_update(struct isis_area *area, uint32_t lower_bound,
 				   uint32_t upper_bound);
-extern void isis_sr_cfg_msd_update(struct isis_area *area);
 extern struct sr_prefix_cfg *
 isis_sr_cfg_prefix_add(struct isis_area *area, const struct prefix *prefix);
 extern void isis_sr_cfg_prefix_del(struct sr_prefix_cfg *pcfg);
diff --git a/isisd/isis_zebra.c b/isisd/isis_zebra.c
index 94ad0ae488..68f80a3f1f 100644
--- a/isisd/isis_zebra.c
+++ b/isisd/isis_zebra.c
@@ -49,6 +49,7 @@
 #include "isisd/isis_lsp.h"
 #include "isisd/isis_route.h"
 #include "isisd/isis_zebra.h"
+#include "isisd/isis_adjacency.h"
 #include "isisd/isis_te.h"
 #include "isisd/isis_sr.h"
 
@@ -254,7 +255,7 @@ void isis_zebra_route_del_route(struct prefix *prefix,
 }
 
 /* Install Prefix-SID in the forwarding plane. */
-void isis_zebra_install_prefix_sid(const struct sr_prefix *srp)
+static void isis_zebra_prefix_install_prefix_sid(const struct sr_prefix *srp)
 {
 	struct zapi_labels zl;
 	struct zapi_nexthop *znh;
@@ -315,7 +316,7 @@ void isis_zebra_install_prefix_sid(const struct sr_prefix *srp)
 }
 
 /* Uninstall Prefix-SID from the forwarding plane. */
-void isis_zebra_uninstall_prefix_sid(const struct sr_prefix *srp)
+static void isis_zebra_uninstall_prefix_sid(const struct sr_prefix *srp)
 {
 	struct zapi_labels zl;
 
@@ -336,6 +337,58 @@ void isis_zebra_uninstall_prefix_sid(const struct sr_prefix *srp)
 	(void)zebra_send_mpls_labels(zclient, ZEBRA_MPLS_LABELS_DELETE, &zl);
 }
 
+void isis_zebra_send_prefix_sid(int cmd, const struct sr_prefix *srp)
+{
+
+	if (cmd != ZEBRA_MPLS_LABELS_REPLACE
+	    && cmd != ZEBRA_MPLS_LABELS_DELETE) {
+		flog_warn(EC_LIB_DEVELOPMENT, "%s: wrong ZEBRA command",
+			  __func__);
+		return;
+	}
+
+	sr_debug("  |- %s label %u for prefix %pFX",
+		 cmd == ZEBRA_MPLS_LABELS_REPLACE ? "Update" : "Delete",
+		 srp->input_label, &srp->prefix);
+
+	if (cmd == ZEBRA_MPLS_LABELS_REPLACE)
+		isis_zebra_prefix_install_prefix_sid(srp);
+	else
+		isis_zebra_uninstall_prefix_sid(srp);
+}
+
+/* Install or uninstall (LAN)-Adj-SID. */
+void isis_zebra_send_adjacency_sid(int cmd, const struct sr_adjacency *sra)
+{
+	struct zapi_labels zl;
+	struct zapi_nexthop *znh;
+
+	if (cmd != ZEBRA_MPLS_LABELS_ADD && cmd != ZEBRA_MPLS_LABELS_DELETE) {
+		flog_warn(EC_LIB_DEVELOPMENT, "%s: wrong ZEBRA command",
+			  __func__);
+		return;
+	}
+
+	sr_debug("  |- %s label %u for interface %s",
+		 cmd == ZEBRA_MPLS_LABELS_ADD ? "Add" : "Delete",
+		 sra->nexthop.label, sra->adj->circuit->interface->name);
+
+	memset(&zl, 0, sizeof(zl));
+	zl.type = ZEBRA_LSP_ISIS_SR;
+	zl.local_label = sra->nexthop.label;
+	zl.nexthop_num = 1;
+	znh = &zl.nexthops[0];
+	znh->gate = sra->nexthop.address;
+	znh->type = (sra->nexthop.family == AF_INET)
+			    ? NEXTHOP_TYPE_IPV4_IFINDEX
+			    : NEXTHOP_TYPE_IPV6_IFINDEX;
+	znh->ifindex = sra->adj->circuit->interface->ifindex;
+	znh->label_num = 1;
+	znh->labels[0] = MPLS_LABEL_IMPLICIT_NULL;
+
+	(void)zebra_send_mpls_labels(zclient, cmd, &zl);
+}
+
 static int isis_zebra_read(ZAPI_CALLBACK_ARGS)
 {
 	struct zapi_route api;
diff --git a/isisd/isis_zebra.h b/isisd/isis_zebra.h
index cca2b08811..b143d34626 100644
--- a/isisd/isis_zebra.h
+++ b/isisd/isis_zebra.h
@@ -36,6 +36,7 @@ void isis_zebra_stop(void);
 
 struct isis_route_info;
 struct sr_prefix;
+struct sr_adjacency;
 
 void isis_zebra_route_add_route(struct prefix *prefix,
 				struct prefix_ipv6 *src_p,
@@ -43,8 +44,8 @@ void isis_zebra_route_add_route(struct prefix *prefix,
 void isis_zebra_route_del_route(struct prefix *prefix,
 				struct prefix_ipv6 *src_p,
 				struct isis_route_info *route_info);
-void isis_zebra_install_prefix_sid(const struct sr_prefix *srp);
-void isis_zebra_uninstall_prefix_sid(const struct sr_prefix *srp);
+void isis_zebra_send_prefix_sid(int cmd, const struct sr_prefix *srp);
+void isis_zebra_send_adjacency_sid(int cmd, const struct sr_adjacency *sra);
 int isis_distribute_list_update(int routetype);
 void isis_zebra_redistribute_set(afi_t afi, int type);
 void isis_zebra_redistribute_unset(afi_t afi, int type);