isisd, yang: implement read-only list of adjacencies

The new "adjacency-state" grouping is almost a 1:1 copy of the
same grouping from the IETF IS-IS module, except for the "usage"
and "lastuptime" leafs that were skipped (more work needs to be
done to support those).

Signed-off-by: Renato Westphal <renato@opensourcerouting.org>

isisd/isis_northbound.c

@@ -48,6 +48,23 @@
 #include "lib/lib_errors.h"
 #include "lib/vrf.h"
 
+/*
+ * Helper functions.
+ */
+static const char *isis_yang_adj_state(enum isis_adj_state state)
+{
+	switch (state) {
+	case ISIS_ADJ_DOWN:
+		return "down";
+	case ISIS_ADJ_UP:
+		return "up";
+	case ISIS_ADJ_INITIALIZING:
+		return "init";
+	default:
+		return "failed";
+	}
+}
+
 /*
  * XPath: /frr-isisd:isis/instance
  */
@@ -2303,6 +2320,169 @@ static int lib_interface_isis_multi_topology_ipv6_dstsrc_modify(
 							ISIS_MT_IPV6_DSTSRC);
 }
 
+/*
+ * XPath: /frr-interface:lib/interface/frr-isisd:isis/adjacencies/adjacency
+ */
+static const void *
+lib_interface_isis_adjacencies_adjacency_get_next(const void *parent_list_entry,
+						  const void *list_entry)
+{
+	struct interface *ifp;
+	struct isis_circuit *circuit;
+	struct isis_adjacency *adj, *adj_next = NULL;
+	struct list *list;
+	struct listnode *node, *node_next;
+
+	/* Get first adjacency. */
+	if (list_entry == NULL) {
+		ifp = (struct interface *)parent_list_entry;
+		if (!ifp)
+			return NULL;
+
+		circuit = circuit_scan_by_ifp(ifp);
+		if (!circuit)
+			return NULL;
+
+		switch (circuit->circ_type) {
+		case CIRCUIT_T_BROADCAST:
+			for (int level = ISIS_LEVEL1; level <= ISIS_LEVELS;
+			     level++) {
+				adj = listnode_head(
+					circuit->u.bc.adjdb[level - 1]);
+				if (adj)
+					break;
+			}
+			break;
+		case CIRCUIT_T_P2P:
+			adj = circuit->u.p2p.neighbor;
+			break;
+		default:
+			adj = NULL;
+			break;
+		}
+
+		return adj;
+	}
+
+	/* Get next adjacency. */
+	adj = (struct isis_adjacency *)list_entry;
+	circuit = adj->circuit;
+	switch (circuit->circ_type) {
+	case CIRCUIT_T_BROADCAST:
+		list = circuit->u.bc.adjdb[adj->level - 1];
+		node = listnode_lookup(list, adj);
+		node_next = listnextnode(node);
+		if (node_next)
+			adj_next = listgetdata(node_next);
+		else if (adj->level == ISIS_LEVEL1) {
+			/*
+			 * Once we finish the L1 adjacencies, move to the L2
+			 * adjacencies list.
+			 */
+			list = circuit->u.bc.adjdb[ISIS_LEVEL2 - 1];
+			adj_next = listnode_head(list);
+		}
+		break;
+	case CIRCUIT_T_P2P:
+		/* P2P circuits have at most one adjacency. */
+	default:
+		break;
+	}
+
+	return adj_next;
+}
+
+/*
+ * XPath:
+ * /frr-interface:lib/interface/frr-isisd:isis/adjacencies/adjacency/neighbor-sys-type
+ */
+static struct yang_data *
+lib_interface_isis_adjacencies_adjacency_neighbor_sys_type_get_elem(
+	const char *xpath, const void *list_entry)
+{
+	const struct isis_adjacency *adj = list_entry;
+
+	return yang_data_new_enum(xpath, adj->level);
+}
+
+/*
+ * XPath:
+ * /frr-interface:lib/interface/frr-isisd:isis/adjacencies/adjacency/neighbor-sysid
+ */
+static struct yang_data *
+lib_interface_isis_adjacencies_adjacency_neighbor_sysid_get_elem(
+	const char *xpath, const void *list_entry)
+{
+	const struct isis_adjacency *adj = list_entry;
+
+	return yang_data_new_string(xpath, sysid_print(adj->sysid));
+}
+
+/*
+ * XPath:
+ * /frr-interface:lib/interface/frr-isisd:isis/adjacencies/adjacency/neighbor-extended-circuit-id
+ */
+static struct yang_data *
+lib_interface_isis_adjacencies_adjacency_neighbor_extended_circuit_id_get_elem(
+	const char *xpath, const void *list_entry)
+{
+	const struct isis_adjacency *adj = list_entry;
+
+	return yang_data_new_uint32(xpath, adj->circuit->circuit_id);
+}
+
+/*
+ * XPath:
+ * /frr-interface:lib/interface/frr-isisd:isis/adjacencies/adjacency/neighbor-snpa
+ */
+static struct yang_data *
+lib_interface_isis_adjacencies_adjacency_neighbor_snpa_get_elem(
+	const char *xpath, const void *list_entry)
+{
+	const struct isis_adjacency *adj = list_entry;
+
+	return yang_data_new_string(xpath, snpa_print(adj->snpa));
+}
+
+/*
+ * XPath:
+ * /frr-interface:lib/interface/frr-isisd:isis/adjacencies/adjacency/hold-timer
+ */
+static struct yang_data *
+lib_interface_isis_adjacencies_adjacency_hold_timer_get_elem(
+	const char *xpath, const void *list_entry)
+{
+	const struct isis_adjacency *adj = list_entry;
+
+	return yang_data_new_uint16(xpath, adj->hold_time);
+}
+
+/*
+ * XPath:
+ * /frr-interface:lib/interface/frr-isisd:isis/adjacencies/adjacency/neighbor-priority
+ */
+static struct yang_data *
+lib_interface_isis_adjacencies_adjacency_neighbor_priority_get_elem(
+	const char *xpath, const void *list_entry)
+{
+	const struct isis_adjacency *adj = list_entry;
+
+	return yang_data_new_uint8(xpath, adj->prio[adj->level - 1]);
+}
+
+/*
+ * XPath:
+ * /frr-interface:lib/interface/frr-isisd:isis/adjacencies/adjacency/state
+ */
+static struct yang_data *
+lib_interface_isis_adjacencies_adjacency_state_get_elem(const char *xpath,
+							const void *list_entry)
+{
+	const struct isis_adjacency *adj = list_entry;
+
+	return yang_data_new_string(xpath, isis_yang_adj_state(adj->adj_state));
+}
+
 /*
  * NOTIFICATIONS
  */
@@ -2545,19 +2725,7 @@ void isis_notif_adj_state_change(const struct isis_adjacency *adj,
 	listnode_add(arguments, data);
 
 	snprintf(xpath_arg, sizeof(xpath_arg), "%s/state", xpath);
-	switch (new_state) {
+	data = yang_data_new_string(xpath_arg, isis_yang_adj_state(new_state));
-	case ISIS_ADJ_DOWN:
-		data = yang_data_new_string(xpath_arg, "down");
-		break;
-	case ISIS_ADJ_UP:
-		data = yang_data_new_string(xpath_arg, "up");
-		break;
-	case ISIS_ADJ_INITIALIZING:
-		data = yang_data_new_string(xpath_arg, "init");
-		break;
-	default:
-		data = yang_data_new_string(xpath_arg, "failed");
-	}
 	listnode_add(arguments, data);
 	if (new_state == ISIS_ADJ_DOWN) {
 		snprintf(xpath_arg, sizeof(xpath_arg), "%s/reason", xpath);
@@ -3483,6 +3651,54 @@ const struct frr_yang_module_info frr_isisd_info = {
 				.modify = lib_interface_isis_multi_topology_ipv6_dstsrc_modify,
 			},
 		},
+		{
+			.xpath = "/frr-interface:lib/interface/frr-isisd:isis/adjacencies/adjacency",
+			.cbs = {
+				.get_next = lib_interface_isis_adjacencies_adjacency_get_next,
+			}
+		},
+		{
+			.xpath = "/frr-interface:lib/interface/frr-isisd:isis/adjacencies/adjacency/neighbor-sys-type",
+			.cbs = {
+				.get_elem = lib_interface_isis_adjacencies_adjacency_neighbor_sys_type_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-interface:lib/interface/frr-isisd:isis/adjacencies/adjacency/neighbor-sysid",
+			.cbs = {
+				.get_elem = lib_interface_isis_adjacencies_adjacency_neighbor_sysid_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-interface:lib/interface/frr-isisd:isis/adjacencies/adjacency/neighbor-extended-circuit-id",
+			.cbs = {
+				.get_elem = lib_interface_isis_adjacencies_adjacency_neighbor_extended_circuit_id_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-interface:lib/interface/frr-isisd:isis/adjacencies/adjacency/neighbor-snpa",
+			.cbs = {
+				.get_elem = lib_interface_isis_adjacencies_adjacency_neighbor_snpa_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-interface:lib/interface/frr-isisd:isis/adjacencies/adjacency/hold-timer",
+			.cbs = {
+				.get_elem = lib_interface_isis_adjacencies_adjacency_hold_timer_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-interface:lib/interface/frr-isisd:isis/adjacencies/adjacency/neighbor-priority",
+			.cbs = {
+				.get_elem = lib_interface_isis_adjacencies_adjacency_neighbor_priority_get_elem,
+			}
+		},
+		{
+			.xpath = "/frr-interface:lib/interface/frr-isisd:isis/adjacencies/adjacency/state",
+			.cbs = {
+				.get_elem = lib_interface_isis_adjacencies_adjacency_state_get_elem,
+			}
+		},
 		{
 			.xpath = NULL,
 		},

yang/frr-isisd.yang

@@ -61,6 +61,13 @@ module frr-isisd {
       "This type defines IS-IS level of an object.";
   }
 
+  typedef extended-circuit-id {
+    type uint32;
+    description
+      "This type defines the extended circuit ID
+       associated with an interface.";
+  }
+
   typedef network-type {
     type enumeration {
       enum "unknown" {
@@ -95,6 +102,20 @@ module frr-isisd {
        pattern, An example LSP ID is 0143.0438.AeF0.02-01";
   }
 
+  typedef snpa {
+    type string {
+      length "0 .. 20";
+    }
+    description
+      "This type defines the Subnetwork Point
+       of Attachment (SNPA) format.
+       The SNPA should be encoded according to the rules
+       specified for the particular type of subnetwork
+       being used. As an example, for an ethernet subnetwork,
+       the SNPA is encoded as a MAC address like
+       '00aa.bbcc.ddee'.";
+  }
+
   typedef system-id {
     type string {
       pattern "[0-9A-Fa-f]{4}\\.[0-9A-Fa-f]{4}\\.[0-9A-Fa-f]{4}";
@@ -544,6 +565,70 @@ module frr-isisd {
     }
   }
 
+  grouping adjacency-state {
+    container adjacencies {
+      config false;
+      list adjacency {
+        leaf neighbor-sys-type {
+          type level;
+          description
+            "Level capability of neighboring system";
+        }
+        leaf neighbor-sysid {
+          type system-id;
+          description
+            "The system-id of the neighbor";
+        }
+        leaf neighbor-extended-circuit-id {
+          type extended-circuit-id;
+          description
+            "Circuit ID of the neighbor";
+        }
+        leaf neighbor-snpa {
+          type snpa;
+          description
+            "SNPA of the neighbor";
+        }
+        leaf hold-timer {
+          type uint16;
+          units seconds;
+          description
+            "The holding time in seconds for this
+             adjacency. This value is based on
+             received hello PDUs and the elapsed
+             time since receipt.";
+        }
+        leaf neighbor-priority {
+          type uint8 {
+            range "0 .. 127";
+          }
+          description
+            "Priority of the neighboring IS for becoming
+             the DIS.";
+        }
+        leaf state {
+          type adj-state-type;
+          description
+            "This leaf describes the state of the interface.";
+        }
+
+        description
+          "List of operational adjacencies.";
+      }
+      description
+        "This container lists the adjacencies of
+         the local node.";
+    }
+    description
+      "Adjacency state";
+  }
+
+  grouping interface-state {
+    description
+      "IS-IS interface operational state.";
+    uses adjacency-state;
+  }
+
   grouping notification-instance-hdr {
     description
       "Instance specific IS-IS notification data grouping";
@@ -582,7 +667,7 @@ module frr-isisd {
     }
 
     leaf extended-circuit-id {
-      type uint32;
+      type extended-circuit-id;
       description
         "Eextended circuit-id of the interface.";
     }
@@ -1003,6 +1088,7 @@ module frr-isisd {
       description
         "IS-IS interface parameters.";
       uses interface-config;
+      uses interface-state;
     }
   }