lib: Add sidStructure in SRv6 SIDs JSON output

The `show ipv6 route json` command displays the IPv6 routing table in
JSON format, including SRv6 SIDs. For each SRv6 SID, it provides
behavior and SID attributes. However, it does not include the SID
structure.

This commit adds the SID structure to the SRv6 SID JSON output.

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

lib/nexthop.c

@@ -1153,6 +1153,7 @@ void nexthop_json_helper(json_object *json_nexthop,
 	json_object *json_backups = NULL;
 	json_object *json_seg6local = NULL;
 	json_object *json_seg6local_context = NULL;
+	json_object *json_srv6_sid_structure = NULL;
 	json_object *json_seg6 = NULL;
 	json_object *json_segs = NULL;
 	int i;
@@ -1328,6 +1329,10 @@ void nexthop_json_helper(json_object *json_nexthop,
 		json_object_object_add(json_nexthop, "seg6localContext",
 				       json_seg6local_context);
 
+		json_srv6_sid_structure = json_object_new_object();
+		srv6_sid_structure2json(&nexthop->nh_srv6->seg6local_ctx, json_srv6_sid_structure);
+		json_object_object_add(json_seg6local, "sidStructure", json_srv6_sid_structure);
+
 		if (nexthop->nh_srv6->seg6_segs &&
 		    nexthop->nh_srv6->seg6_segs->num_segs == 1) {
 			json_seg6 = json_object_new_object();

lib/srv6.c

@@ -71,6 +71,14 @@ int snprintf_seg6_segs(char *str,
 	return strlen(str);
 }
 
+void srv6_sid_structure2json(const struct seg6local_context *ctx, json_object *json)
+{
+	json_object_int_add(json, "blockLen", ctx->block_len);
+	json_object_int_add(json, "nodeLen", ctx->node_len);
+	json_object_int_add(json, "funcLen", ctx->function_len);
+	json_object_int_add(json, "argLen", ctx->argument_len);
+}
+
 void seg6local_context2json(const struct seg6local_context *ctx,
 			    uint32_t action, json_object *json)
 {

lib/srv6.h

@@ -363,6 +363,7 @@ const char *seg6local_context2str(char *str, size_t size,
 				  uint32_t action);
 void seg6local_context2json(const struct seg6local_context *ctx,
 			    uint32_t action, json_object *json);
+void srv6_sid_structure2json(const struct seg6local_context *ctx, json_object *json);
 
 static inline const char *srv6_sid_ctx2str(char *str, size_t size,
 					   const struct srv6_sid_ctx *ctx)