ripngd: retrofit the 'router ripng' command to the new northbound model

* Implement the northbound callbacks associated to the
  '/frr-ripngd:ripngd/instance' YANG path (the code is mostly a copy
  and paste from the original "router ripng" DEFUNs);
* Move ripng_make_socket() out of ripng_create() since creating a
  socket is an error-prone operation and thus needs to be performed
  separately during the NB_EV_PREPARE phase;
* On ripng_create(), fetch the defaults from the frr-ripngd YANG
  model;
* Convert the "[no] router ripng" CLI commands to be dumb wrappers
  around the northbound callbacks;
* On ripng_config_write(), write logic to call all 'cli_show'
  northbound callbacks defined under the '/frr-ripngd:ripngd/instance'
  YANG path.

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

5 files changed, 97 insertions, 58 deletions

diff --git a/ripngd/ripng_cli.c b/ripngd/ripng_cli.c
index b033a39ac..7bdc74220 100644
--- a/ripngd/ripng_cli.c
+++ b/ripngd/ripng_cli.c
@@ -34,6 +34,49 @@
 #include "ripngd/ripng_cli_clippy.c"
 #endif
 
+/*
+ * XPath: /frr-ripngd:ripngd/instance
+ */
+DEFPY_NOSH (router_ripng,
+       router_ripng_cmd,
+       "router ripng",
+       "Enable a routing process\n"
+       "Make RIPng instance command\n")
+{
+	int ret;
+
+	nb_cli_enqueue_change(vty, "/frr-ripngd:ripngd/instance", NB_OP_CREATE,
+			      NULL);
+
+	ret = nb_cli_apply_changes(vty, NULL);
+	if (ret == CMD_SUCCESS)
+		VTY_PUSH_XPATH(RIPNG_NODE, "/frr-ripngd:ripngd/instance");
+
+	return ret;
+}
+
+DEFPY (no_router_ripng,
+       no_router_ripng_cmd,
+       "no router ripng",
+       NO_STR
+       "Enable a routing process\n"
+       "Make RIPng instance command\n")
+{
+	nb_cli_enqueue_change(vty, "/frr-ripngd:ripngd/instance", NB_OP_DELETE,
+			      NULL);
+
+	return nb_cli_apply_changes(vty, NULL);
+}
+
+void cli_show_router_ripng(struct vty *vty, struct lyd_node *dnode,
+			 bool show_defaults)
+{
+	vty_out(vty, "!\n");
+	vty_out(vty, "router ripng\n");
+}
+
 void ripng_cli_init(void)
 {
+	install_element(CONFIG_NODE, &router_ripng_cmd);
+	install_element(CONFIG_NODE, &no_router_ripng_cmd);
 }
diff --git a/ripngd/ripng_cli.h b/ripngd/ripng_cli.h
index a3f29b985..f0ef046f6 100644
--- a/ripngd/ripng_cli.h
+++ b/ripngd/ripng_cli.h
@@ -21,4 +21,7 @@
 #ifndef _FRR_RIPNG_CLI_H_
 #define _FRR_RIPNG_CLI_H_
 
+extern void cli_show_router_ripng(struct vty *vty, struct lyd_node *dnode,
+				  bool show_defaults);
+
 #endif /* _FRR_RIPNG_CLI_H_ */
diff --git a/ripngd/ripng_northbound.c b/ripngd/ripng_northbound.c
index 84e4bf43e..219d8d1db 100644
--- a/ripngd/ripng_northbound.c
+++ b/ripngd/ripng_northbound.c
@@ -40,14 +40,38 @@ static int ripngd_instance_create(enum nb_event event,
 				  const struct lyd_node *dnode,
 				  union nb_resource *resource)
 {
-	/* TODO: implement me. */
+	int socket;
+
+	switch (event) {
+	case NB_EV_VALIDATE:
+		break;
+	case NB_EV_PREPARE:
+		socket = ripng_make_socket();
+		if (socket < 0)
+			return NB_ERR_RESOURCE;
+		resource->fd = socket;
+		break;
+	case NB_EV_ABORT:
+		socket = resource->fd;
+		close(socket);
+		break;
+	case NB_EV_APPLY:
+		socket = resource->fd;
+		ripng_create(socket);
+		break;
+	}
+
 	return NB_OK;
 }
 
 static int ripngd_instance_delete(enum nb_event event,
 				  const struct lyd_node *dnode)
 {
-	/* TODO: implement me. */
+	if (event != NB_EV_APPLY)
+		return NB_OK;
+
+	ripng_clean();
+
 	return NB_OK;
 }
 
@@ -484,6 +508,7 @@ const struct frr_yang_module_info frr_ripngd_info = {
 			.xpath = "/frr-ripngd:ripngd/instance",
 			.cbs.create = ripngd_instance_create,
 			.cbs.delete = ripngd_instance_delete,
+			.cbs.cli_show = cli_show_router_ripng,
 		},
 		{
 			.xpath = "/frr-ripngd:ripngd/instance/allow-ecmp",
diff --git a/ripngd/ripngd.c b/ripngd/ripngd.c
index 2cbbbae7f..634596719 100644
--- a/ripngd/ripngd.c
+++ b/ripngd/ripngd.c
@@ -36,6 +36,7 @@
 #include "if_rmap.h"
 #include "privs.h"
 #include "lib_errors.h"
+#include "northbound_cli.h"
 
 #include "ripngd/ripngd.h"
 #include "ripngd/ripng_route.h"
@@ -87,7 +88,7 @@ void ripng_info_free(struct ripng_info *rinfo)
 }
 
 /* Create ripng socket. */
-static int ripng_make_socket(void)
+int ripng_make_socket(void)
 {
 	int ret;
 	int sock;
@@ -1778,7 +1779,7 @@ void ripng_output_process(struct interface *ifp, struct sockaddr_in6 *to,
 }
 
 /* Create new RIPng instance and set it to global variable. */
-static int ripng_create(void)
+int ripng_create(int socket)
 {
 	/* ripng should be NULL. */
 	assert(ripng == NULL);
@@ -1788,10 +1789,15 @@ static int ripng_create(void)
 
 	/* Default version and timer values. */
 	ripng->version = RIPNG_V1;
-	ripng->update_time = RIPNG_UPDATE_TIMER_DEFAULT;
-	ripng->timeout_time = RIPNG_TIMEOUT_TIMER_DEFAULT;
-	ripng->garbage_time = RIPNG_GARBAGE_TIMER_DEFAULT;
-	ripng->default_metric = RIPNG_DEFAULT_METRIC_DEFAULT;
+	ripng->update_time = yang_get_default_uint32(
+		"%s/timers/update-interval", RIPNG_INSTANCE);
+	ripng->timeout_time = yang_get_default_uint32(
+		"%s/timers/holddown-interval", RIPNG_INSTANCE);
+	ripng->garbage_time = yang_get_default_uint32(
+		"%s/timers/flush-interval", RIPNG_INSTANCE);
+	ripng->default_metric =
+		yang_get_default_uint8("%s/default-metric", RIPNG_INSTANCE);
+	ripng->ecmp = yang_get_default_bool("%s/allow-ecmp", RIPNG_INSTANCE);
 
 	/* Make buffer.  */
 	ripng->ibuf = stream_new(RIPNG_MAX_PACKET_SIZE * 5);
@@ -1803,9 +1809,7 @@ static int ripng_create(void)
 	ripng->aggregate = agg_table_init();
 
 	/* Make socket. */
-	ripng->sock = ripng_make_socket();
-	if (ripng->sock < 0)
-		return ripng->sock;
+	ripng->sock = socket;
 
 	/* Threads. */
 	ripng_event(RIPNG_READ, ripng->sock);
@@ -2153,41 +2157,6 @@ DEFUN (clear_ipv6_rip,
 	return CMD_SUCCESS;
 }
 
-DEFUN_NOSH (router_ripng,
-       router_ripng_cmd,
-       "router ripng",
-       "Enable a routing process\n"
-       "Make RIPng instance command\n")
-{
-	int ret;
-
-	vty->node = RIPNG_NODE;
-
-	if (!ripng) {
-		ret = ripng_create();
-
-		/* Notice to user we couldn't create RIPng. */
-		if (ret < 0) {
-			zlog_warn("can't create RIPng");
-			return CMD_WARNING_CONFIG_FAILED;
-		}
-	}
-
-	return CMD_SUCCESS;
-}
-
-DEFUN (no_router_ripng,
-       no_router_ripng_cmd,
-       "no router ripng",
-       NO_STR
-       "Enable a routing process\n"
-       "Make RIPng instance command\n")
-{
-	if (ripng)
-		ripng_clean();
-	return CMD_SUCCESS;
-}
-
 DEFUN (ripng_route,
        ripng_route_cmd,
        "route IPV6ADDR",
@@ -2643,15 +2612,14 @@ DEFUN (no_ripng_allow_ecmp,
 /* RIPng configuration write function. */
 static int ripng_config_write(struct vty *vty)
 {
-	int ripng_network_write(struct vty *, int);
-	void ripng_redistribute_write(struct vty *, int);
+	struct lyd_node *dnode;
 	int write = 0;
 	struct agg_node *rp;
 
-	if (ripng) {
-
-		/* RIPng router. */
-		vty_out(vty, "router ripng\n");
+	dnode = yang_dnode_get(running_config->dnode,
+			       "/frr-ripngd:ripngd/instance");
+	if (dnode) {
+		nb_cli_show_dnode_cmds(vty, dnode, false);
 
 		if (ripng->default_information)
 			vty_out(vty, " default-information originate\n");
@@ -2705,12 +2673,13 @@ static int ripng_config_write(struct vty *vty)
 	vty_out (vty, " garbage-timer %d\n", ripng->garbage_time);
 #endif /* 0 */
 
-		write += config_write_distribute(vty);
+		config_write_distribute(vty);
 
-		write += config_write_if_rmap(vty);
+		config_write_if_rmap(vty);
 
-		write++;
+		write = 1;
 	}
+
 	return write;
 }
 
@@ -2989,9 +2958,6 @@ void ripng_init()
 
 	install_element(ENABLE_NODE, &clear_ipv6_rip_cmd);
 
-	install_element(CONFIG_NODE, &router_ripng_cmd);
-	install_element(CONFIG_NODE, &no_router_ripng_cmd);
-
 	install_default(RIPNG_NODE);
 	install_element(RIPNG_NODE, &ripng_route_cmd);
 	install_element(RIPNG_NODE, &no_ripng_route_cmd);
diff --git a/ripngd/ripngd.h b/ripngd/ripngd.h
index 7d4f822da..de3b2e194 100644
--- a/ripngd/ripngd.h
+++ b/ripngd/ripngd.h
@@ -410,6 +410,8 @@ extern int ripng_interface_address_add(int command, struct zclient *,
 extern int ripng_interface_address_delete(int command, struct zclient *,
 					  zebra_size_t, vrf_id_t);
 
+extern int ripng_create(int socket);
+extern int ripng_make_socket(void);
 extern int ripng_network_write(struct vty *, int);
 
 extern struct ripng_info *ripng_ecmp_add(struct ripng_info *);