mirror_frr/lib/mgmt_fe_client.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * MGMTD Frontend Client Library api interfaces
 * Copyright (C) 2021  Vmware, Inc.
 *		       Pushpasis Sarkar <spushpasis@vmware.com>
 */

#include <zebra.h>
#include "compiler.h"
#include "debug.h"
#include "memory.h"
#include "libfrr.h"
#include "mgmt_fe_client.h"
#include "mgmt_msg.h"
#include "mgmt_pb.h"
#include "network.h"
#include "stream.h"
#include "sockopt.h"

#include "lib/mgmt_fe_client_clippy.c"

PREDECL_LIST(mgmt_sessions);

struct mgmt_fe_client_session {
	uint64_t client_id;  /* FE client identifies itself with this ID */
	uint64_t session_id; /* FE adapter identified session with this ID */
	struct mgmt_fe_client *client;
	uintptr_t user_ctx;

	struct mgmt_sessions_item list_linkage;
};

DECLARE_LIST(mgmt_sessions, struct mgmt_fe_client_session, list_linkage);

DEFINE_MTYPE_STATIC(LIB, MGMTD_FE_CLIENT, "frontend client");
DEFINE_MTYPE_STATIC(LIB, MGMTD_FE_CLIENT_NAME, "frontend client name");
DEFINE_MTYPE_STATIC(LIB, MGMTD_FE_SESSION, "frontend session");

struct mgmt_fe_client {
	struct msg_client client;
	char *name;
	struct mgmt_fe_client_cbs cbs;
	uintptr_t user_data;
	struct mgmt_sessions_head sessions;
};

#define FOREACH_SESSION_IN_LIST(client, session)                               \
	frr_each_safe (mgmt_sessions, &(client)->sessions, (session))

struct debug mgmt_dbg_fe_client = {0, "Management frontend client operations"};


static struct mgmt_fe_client_session *
mgmt_fe_find_session_by_client_id(struct mgmt_fe_client *client,
				  uint64_t client_id)
{
	struct mgmt_fe_client_session *session;

	FOREACH_SESSION_IN_LIST (client, session) {
		if (session->client_id == client_id) {
			MGMTD_FE_CLIENT_DBG("Found session-id %" PRIu64
					    " using client-id %" PRIu64,
					    session->session_id, client_id);
			return session;
		}
	}
	MGMTD_FE_CLIENT_DBG("Session not found using client-id %" PRIu64,
			    client_id);
	return NULL;
}

static struct mgmt_fe_client_session *
mgmt_fe_find_session_by_session_id(struct mgmt_fe_client *client,
				   uint64_t session_id)
{
	struct mgmt_fe_client_session *session;

	FOREACH_SESSION_IN_LIST (client, session) {
		if (session->session_id == session_id) {
			MGMTD_FE_CLIENT_DBG(
				"Found session of client-id %" PRIu64
				" using session-id %" PRIu64,
				session->client_id, session_id);
			return session;
		}
	}
	MGMTD_FE_CLIENT_DBG("Session not found using session-id %" PRIu64,
			    session_id);
	return NULL;
}

static int mgmt_fe_client_send_msg(struct mgmt_fe_client *client,
				   Mgmtd__FeMessage *fe_msg,
				   bool short_circuit_ok)
{
	return msg_conn_send_msg(
		&client->client.conn, MGMT_MSG_VERSION_PROTOBUF, fe_msg,
		mgmtd__fe_message__get_packed_size(fe_msg),
		(size_t(*)(void *, void *))mgmtd__fe_message__pack,
		short_circuit_ok);
}

static int mgmt_fe_send_register_req(struct mgmt_fe_client *client)
{
	Mgmtd__FeMessage fe_msg;
	Mgmtd__FeRegisterReq rgstr_req;

	mgmtd__fe_register_req__init(&rgstr_req);
	rgstr_req.client_name = client->name;

	mgmtd__fe_message__init(&fe_msg);
	fe_msg.message_case = MGMTD__FE_MESSAGE__MESSAGE_REGISTER_REQ;
	fe_msg.register_req = &rgstr_req;

	MGMTD_FE_CLIENT_DBG(
		"Sending REGISTER_REQ message to MGMTD Frontend server");

	return mgmt_fe_client_send_msg(client, &fe_msg, true);
}

static int mgmt_fe_send_session_req(struct mgmt_fe_client *client,
				    struct mgmt_fe_client_session *session,
				    bool create)
{
	Mgmtd__FeMessage fe_msg;
	Mgmtd__FeSessionReq sess_req;
	bool scok;

	mgmtd__fe_session_req__init(&sess_req);
	sess_req.create = create;
	if (create) {
		sess_req.id_case = MGMTD__FE_SESSION_REQ__ID_CLIENT_CONN_ID;
		sess_req.client_conn_id = session->client_id;
		scok = true;
	} else {
		sess_req.id_case = MGMTD__FE_SESSION_REQ__ID_SESSION_ID;
		sess_req.session_id = session->session_id;
		scok = false;
	}

	mgmtd__fe_message__init(&fe_msg);
	fe_msg.message_case = MGMTD__FE_MESSAGE__MESSAGE_SESSION_REQ;
	fe_msg.session_req = &sess_req;

	MGMTD_FE_CLIENT_DBG(
		"Sending SESSION_REQ %s message for client-id %" PRIu64,
		create ? "create" : "destroy", session->client_id);

	return mgmt_fe_client_send_msg(client, &fe_msg, scok);
}

int mgmt_fe_send_lockds_req(struct mgmt_fe_client *client, uint64_t session_id,
			    uint64_t req_id, Mgmtd__DatastoreId ds_id,
			    bool lock)
{
	(void)req_id;
	Mgmtd__FeMessage fe_msg;
	Mgmtd__FeLockDsReq lockds_req;

	mgmtd__fe_lock_ds_req__init(&lockds_req);
	lockds_req.session_id = session_id;
	lockds_req.req_id = req_id;
	lockds_req.ds_id = ds_id;
	lockds_req.lock = lock;

	mgmtd__fe_message__init(&fe_msg);
	fe_msg.message_case = MGMTD__FE_MESSAGE__MESSAGE_LOCKDS_REQ;
	fe_msg.lockds_req = &lockds_req;

	MGMTD_FE_CLIENT_DBG(
		"Sending %sLOCK_REQ message for Ds:%d session-id %" PRIu64,
		lock ? "" : "UN", ds_id, session_id);

	return mgmt_fe_client_send_msg(client, &fe_msg, false);
}

int mgmt_fe_send_setcfg_req(struct mgmt_fe_client *client, uint64_t session_id,
			    uint64_t req_id, Mgmtd__DatastoreId ds_id,
			    Mgmtd__YangCfgDataReq **data_req, int num_data_reqs,
			    bool implicit_commit, Mgmtd__DatastoreId dst_ds_id)
{
	(void)req_id;
	Mgmtd__FeMessage fe_msg;
	Mgmtd__FeSetConfigReq setcfg_req;

	mgmtd__fe_set_config_req__init(&setcfg_req);
	setcfg_req.session_id = session_id;
	setcfg_req.ds_id = ds_id;
	setcfg_req.req_id = req_id;
	setcfg_req.data = data_req;
	setcfg_req.n_data = (size_t)num_data_reqs;
	setcfg_req.implicit_commit = implicit_commit;
	setcfg_req.commit_ds_id = dst_ds_id;

	mgmtd__fe_message__init(&fe_msg);
	fe_msg.message_case = MGMTD__FE_MESSAGE__MESSAGE_SETCFG_REQ;
	fe_msg.setcfg_req = &setcfg_req;

	MGMTD_FE_CLIENT_DBG(
		"Sending SET_CONFIG_REQ message for Ds:%d session-id %" PRIu64
		" (#xpaths:%d)",
		ds_id, session_id, num_data_reqs);

	return mgmt_fe_client_send_msg(client, &fe_msg, false);
}

int mgmt_fe_send_commitcfg_req(struct mgmt_fe_client *client,
			       uint64_t session_id, uint64_t req_id,
			       Mgmtd__DatastoreId src_ds_id,
			       Mgmtd__DatastoreId dest_ds_id,
			       bool validate_only, bool abort)
{
	(void)req_id;
	Mgmtd__FeMessage fe_msg;
	Mgmtd__FeCommitConfigReq commitcfg_req;

	mgmtd__fe_commit_config_req__init(&commitcfg_req);
	commitcfg_req.session_id = session_id;
	commitcfg_req.src_ds_id = src_ds_id;
	commitcfg_req.dst_ds_id = dest_ds_id;
	commitcfg_req.req_id = req_id;
	commitcfg_req.validate_only = validate_only;
	commitcfg_req.abort = abort;

	mgmtd__fe_message__init(&fe_msg);
	fe_msg.message_case = MGMTD__FE_MESSAGE__MESSAGE_COMMCFG_REQ;
	fe_msg.commcfg_req = &commitcfg_req;

	MGMTD_FE_CLIENT_DBG(
		"Sending COMMIT_CONFIG_REQ message for Src-Ds:%d, Dst-Ds:%d session-id %" PRIu64,
		src_ds_id, dest_ds_id, session_id);

	return mgmt_fe_client_send_msg(client, &fe_msg, false);
}

int mgmt_fe_send_getcfg_req(struct mgmt_fe_client *client, uint64_t session_id,
			    uint64_t req_id, Mgmtd__DatastoreId ds_id,
			    Mgmtd__YangGetDataReq *data_req[],
			    int num_data_reqs)
{
	(void)req_id;
	Mgmtd__FeMessage fe_msg;
	Mgmtd__FeGetConfigReq getcfg_req;

	mgmtd__fe_get_config_req__init(&getcfg_req);
	getcfg_req.session_id = session_id;
	getcfg_req.ds_id = ds_id;
	getcfg_req.req_id = req_id;
	getcfg_req.data = data_req;
	getcfg_req.n_data = (size_t)num_data_reqs;

	mgmtd__fe_message__init(&fe_msg);
	fe_msg.message_case = MGMTD__FE_MESSAGE__MESSAGE_GETCFG_REQ;
	fe_msg.getcfg_req = &getcfg_req;

	MGMTD_FE_CLIENT_DBG(
		"Sending GET_CONFIG_REQ message for Ds:%d session-id %" PRIu64
		" (#xpaths:%d)",
		ds_id, session_id, num_data_reqs);

	return mgmt_fe_client_send_msg(client, &fe_msg, false);
}

int mgmt_fe_send_getdata_req(struct mgmt_fe_client *client, uint64_t session_id,
			     uint64_t req_id, Mgmtd__DatastoreId ds_id,
			     Mgmtd__YangGetDataReq *data_req[],
			     int num_data_reqs)
{
	(void)req_id;
	Mgmtd__FeMessage fe_msg;
	Mgmtd__FeGetDataReq getdata_req;

	mgmtd__fe_get_data_req__init(&getdata_req);
	getdata_req.session_id = session_id;
	getdata_req.ds_id = ds_id;
	getdata_req.req_id = req_id;
	getdata_req.data = data_req;
	getdata_req.n_data = (size_t)num_data_reqs;

	mgmtd__fe_message__init(&fe_msg);
	fe_msg.message_case = MGMTD__FE_MESSAGE__MESSAGE_GETDATA_REQ;
	fe_msg.getdata_req = &getdata_req;

	MGMTD_FE_CLIENT_DBG(
		"Sending GET_CONFIG_REQ message for Ds:%d session-id %" PRIu64
		" (#xpaths:%d)",
		ds_id, session_id, num_data_reqs);

	return mgmt_fe_client_send_msg(client, &fe_msg, false);
}

int mgmt_fe_send_regnotify_req(struct mgmt_fe_client *client,
			       uint64_t session_id, uint64_t req_id,
			       Mgmtd__DatastoreId ds_id, bool register_req,
			       Mgmtd__YangDataXPath *data_req[],
			       int num_data_reqs)
{
	(void)req_id;
	Mgmtd__FeMessage fe_msg;
	Mgmtd__FeRegisterNotifyReq regntfy_req;

	mgmtd__fe_register_notify_req__init(&regntfy_req);
	regntfy_req.session_id = session_id;
	regntfy_req.ds_id = ds_id;
	regntfy_req.register_req = register_req;
	regntfy_req.data_xpath = data_req;
	regntfy_req.n_data_xpath = (size_t)num_data_reqs;

	mgmtd__fe_message__init(&fe_msg);
	fe_msg.message_case = MGMTD__FE_MESSAGE__MESSAGE_REGNOTIFY_REQ;
	fe_msg.regnotify_req = &regntfy_req;

	return mgmt_fe_client_send_msg(client, &fe_msg, false);
}

static int mgmt_fe_client_handle_msg(struct mgmt_fe_client *client,
				     Mgmtd__FeMessage *fe_msg)
{
	struct mgmt_fe_client_session *session = NULL;

	/*
	 * protobuf-c adds a max size enum with an internal, and changing by
	 * version, name; cast to an int to avoid unhandled enum warnings
	 */
	switch ((int)fe_msg->message_case) {
	case MGMTD__FE_MESSAGE__MESSAGE_SESSION_REPLY:
		if (fe_msg->session_reply->create &&
		    fe_msg->session_reply->has_client_conn_id) {
			MGMTD_FE_CLIENT_DBG(
				"Got SESSION_REPLY (create) for client-id %" PRIu64
				" with session-id: %" PRIu64,
				fe_msg->session_reply->client_conn_id,
				fe_msg->session_reply->session_id);

			session = mgmt_fe_find_session_by_client_id(
				client, fe_msg->session_reply->client_conn_id);

			if (session && fe_msg->session_reply->success) {
				MGMTD_FE_CLIENT_DBG(
					"Session Created for client-id %" PRIu64,
					fe_msg->session_reply->client_conn_id);
				session->session_id =
					fe_msg->session_reply->session_id;
			} else {
				MGMTD_FE_CLIENT_ERR(
					"Session Create failed for client-id %" PRIu64,
					fe_msg->session_reply->client_conn_id);
			}
		} else if (!fe_msg->session_reply->create) {
			MGMTD_FE_CLIENT_DBG(
				"Got SESSION_REPLY (destroy) for session-id %" PRIu64,
				fe_msg->session_reply->session_id);

			session = mgmt_fe_find_session_by_session_id(
				client, fe_msg->session_req->session_id);
		}

		/* The session state may be deleted by the callback */
		if (session && session->client &&
		    session->client->cbs.client_session_notify)
			(*session->client->cbs.client_session_notify)(
				client, client->user_data, session->client_id,
				fe_msg->session_reply->create,
				fe_msg->session_reply->success,
				fe_msg->session_reply->session_id,
				session->user_ctx);
		break;
	case MGMTD__FE_MESSAGE__MESSAGE_LOCKDS_REPLY:
		MGMTD_FE_CLIENT_DBG("Got LOCKDS_REPLY for session-id %" PRIu64,
				    fe_msg->lockds_reply->session_id);
		session = mgmt_fe_find_session_by_session_id(
			client, fe_msg->lockds_reply->session_id);

		if (session && session->client &&
		    session->client->cbs.lock_ds_notify)
			(*session->client->cbs.lock_ds_notify)(
				client, client->user_data, session->client_id,
				fe_msg->lockds_reply->session_id,
				session->user_ctx, fe_msg->lockds_reply->req_id,
				fe_msg->lockds_reply->lock,
				fe_msg->lockds_reply->success,
				fe_msg->lockds_reply->ds_id,
				fe_msg->lockds_reply->error_if_any);
		break;
	case MGMTD__FE_MESSAGE__MESSAGE_SETCFG_REPLY:
		MGMTD_FE_CLIENT_DBG("Got SETCFG_REPLY for session-id %" PRIu64,
				    fe_msg->setcfg_reply->session_id);

		session = mgmt_fe_find_session_by_session_id(
			client, fe_msg->setcfg_reply->session_id);

		if (session && session->client &&
		    session->client->cbs.set_config_notify)
			(*session->client->cbs.set_config_notify)(
				client, client->user_data, session->client_id,
				fe_msg->setcfg_reply->session_id,
				session->user_ctx, fe_msg->setcfg_reply->req_id,
				fe_msg->setcfg_reply->success,
				fe_msg->setcfg_reply->ds_id,
				fe_msg->setcfg_reply->error_if_any);
		break;
	case MGMTD__FE_MESSAGE__MESSAGE_COMMCFG_REPLY:
		MGMTD_FE_CLIENT_DBG("Got COMMCFG_REPLY for session-id %" PRIu64,
				    fe_msg->commcfg_reply->session_id);

		session = mgmt_fe_find_session_by_session_id(
			client, fe_msg->commcfg_reply->session_id);

		if (session && session->client &&
		    session->client->cbs.commit_config_notify)
			(*session->client->cbs.commit_config_notify)(
				client, client->user_data, session->client_id,
				fe_msg->commcfg_reply->session_id,
				session->user_ctx,
				fe_msg->commcfg_reply->req_id,
				fe_msg->commcfg_reply->success,
				fe_msg->commcfg_reply->src_ds_id,
				fe_msg->commcfg_reply->dst_ds_id,
				fe_msg->commcfg_reply->validate_only,
				fe_msg->commcfg_reply->error_if_any);
		break;
	case MGMTD__FE_MESSAGE__MESSAGE_GETCFG_REPLY:
		MGMTD_FE_CLIENT_DBG("Got GETCFG_REPLY for session-id %" PRIu64,
				    fe_msg->getcfg_reply->session_id);

		session = mgmt_fe_find_session_by_session_id(
			client, fe_msg->getcfg_reply->session_id);

		if (session && session->client &&
		    session->client->cbs.get_data_notify)
			(*session->client->cbs.get_data_notify)(
				client, client->user_data, session->client_id,
				fe_msg->getcfg_reply->session_id,
				session->user_ctx, fe_msg->getcfg_reply->req_id,
				fe_msg->getcfg_reply->success,
				fe_msg->getcfg_reply->ds_id,
				fe_msg->getcfg_reply->data
					? fe_msg->getcfg_reply->data->data
					: NULL,
				fe_msg->getcfg_reply->data
					? fe_msg->getcfg_reply->data->n_data
					: 0,
				fe_msg->getcfg_reply->data
					? fe_msg->getcfg_reply->data->next_indx
					: 0,
				fe_msg->getcfg_reply->error_if_any);
		break;
	case MGMTD__FE_MESSAGE__MESSAGE_GETDATA_REPLY:
		MGMTD_FE_CLIENT_DBG("Got GETDATA_REPLY for session-id %" PRIu64,
				    fe_msg->getdata_reply->session_id);

		session = mgmt_fe_find_session_by_session_id(
			client, fe_msg->getdata_reply->session_id);

		if (session && session->client &&
		    session->client->cbs.get_data_notify)
			(*session->client->cbs.get_data_notify)(
				client, client->user_data, session->client_id,
				fe_msg->getdata_reply->session_id,
				session->user_ctx,
				fe_msg->getdata_reply->req_id,
				fe_msg->getdata_reply->success,
				fe_msg->getdata_reply->ds_id,
				fe_msg->getdata_reply->data
					? fe_msg->getdata_reply->data->data
					: NULL,
				fe_msg->getdata_reply->data
					? fe_msg->getdata_reply->data->n_data
					: 0,
				fe_msg->getdata_reply->data
					? fe_msg->getdata_reply->data->next_indx
					: 0,
				fe_msg->getdata_reply->error_if_any);
		break;
	case MGMTD__FE_MESSAGE__MESSAGE_NOTIFY_DATA_REQ:
	case MGMTD__FE_MESSAGE__MESSAGE_REGNOTIFY_REQ:
		/*
		 * TODO: Add handling code in future.
		 */
		break;
	/*
	 * NOTE: The following messages are always sent from Frontend
	 * clients to MGMTd only and/or need not be handled here.
	 */
	case MGMTD__FE_MESSAGE__MESSAGE_REGISTER_REQ:
	case MGMTD__FE_MESSAGE__MESSAGE_SESSION_REQ:
	case MGMTD__FE_MESSAGE__MESSAGE_LOCKDS_REQ:
	case MGMTD__FE_MESSAGE__MESSAGE_SETCFG_REQ:
	case MGMTD__FE_MESSAGE__MESSAGE_COMMCFG_REQ:
	case MGMTD__FE_MESSAGE__MESSAGE_GETCFG_REQ:
	case MGMTD__FE_MESSAGE__MESSAGE_GETDATA_REQ:
	case MGMTD__FE_MESSAGE__MESSAGE__NOT_SET:
	default:
		/*
		 * A 'default' case is being added contrary to the
		 * FRR code guidelines to take care of build
		 * failures on certain build systems (courtesy of
		 * the proto-c package).
		 */
		break;
	}

	return 0;
}

static void mgmt_fe_client_process_msg(uint8_t version, uint8_t *data,
				       size_t len, struct msg_conn *conn)
{
	struct mgmt_fe_client *client;
	struct msg_client *msg_client;
	Mgmtd__FeMessage *fe_msg;

	msg_client = container_of(conn, struct msg_client, conn);
	client = container_of(msg_client, struct mgmt_fe_client, client);

	fe_msg = mgmtd__fe_message__unpack(NULL, len, data);
	if (!fe_msg) {
		MGMTD_FE_CLIENT_DBG("Failed to decode %zu bytes from server.",
				    len);
		return;
	}
	MGMTD_FE_CLIENT_DBG(
		"Decoded %zu bytes of message(msg: %u/%u) from server", len,
		fe_msg->message_case, fe_msg->message_case);
	(void)mgmt_fe_client_handle_msg(client, fe_msg);
	mgmtd__fe_message__free_unpacked(fe_msg, NULL);
}

static int _notify_connect_disconnect(struct msg_client *msg_client,
				      bool connected)
{
	struct mgmt_fe_client *client =
		container_of(msg_client, struct mgmt_fe_client, client);
	struct mgmt_fe_client_session *session;
	int ret;

	/* Send REGISTER_REQ message */
	if (connected) {
		if ((ret = mgmt_fe_send_register_req(client)) != 0)
			return ret;
	}

	/* Walk list of sessions for this FE client deleting them */
	if (!connected && mgmt_sessions_count(&client->sessions)) {
		MGMTD_FE_CLIENT_DBG("Cleaning up existing sessions");

		FOREACH_SESSION_IN_LIST (client, session) {
			assert(session->client);

			/* unlink from list first this avoids double free */
			mgmt_sessions_del(&client->sessions, session);

			/* notify FE client the session is being deleted */
			if (session->client->cbs.client_session_notify) {
				(*session->client->cbs.client_session_notify)(
					client, client->user_data,
					session->client_id, false, true,
					session->session_id, session->user_ctx);
			}

			XFREE(MTYPE_MGMTD_FE_SESSION, session);
		}
	}

	/* Notify FE client through registered callback (if any). */
	if (client->cbs.client_connect_notify)
		(void)(*client->cbs.client_connect_notify)(
			client, client->user_data, connected);
	return 0;
}

static int mgmt_fe_client_notify_connect(struct msg_client *client)
{
	return _notify_connect_disconnect(client, true);
}

static int mgmt_fe_client_notify_disconnect(struct msg_conn *conn)
{
	struct msg_client *client = container_of(conn, struct msg_client, conn);

	return _notify_connect_disconnect(client, false);
}


DEFPY(debug_mgmt_client_fe, debug_mgmt_client_fe_cmd,
      "[no] debug mgmt client frontend",
      NO_STR DEBUG_STR MGMTD_STR
      "client\n"
      "frontend\n")
{
	uint32_t mode = DEBUG_NODE2MODE(vty->node);

	DEBUG_MODE_SET(&mgmt_dbg_fe_client, mode, !no);

	return CMD_SUCCESS;
}

static void mgmt_debug_client_fe_set_all(uint32_t flags, bool set)
{
	DEBUG_FLAGS_SET(&mgmt_dbg_fe_client, flags, set);
}

static int mgmt_debug_fe_client_config_write(struct vty *vty)
{
	if (DEBUG_MODE_CHECK(&mgmt_dbg_fe_client, DEBUG_MODE_CONF))
		vty_out(vty, "debug mgmt client frontend\n");

	return CMD_SUCCESS;
}

void mgmt_debug_fe_client_show_debug(struct vty *vty)
{
	if (MGMTD_DBG_FE_CLIENT_CHECK())
		vty_out(vty, "debug mgmt client frontend\n");
}

static struct debug_callbacks mgmt_dbg_fe_client_cbs = {
	.debug_set_all = mgmt_debug_client_fe_set_all};

static struct cmd_node mgmt_dbg_node = {
	.name = "mgmt client frontend",
	.node = DEBUG_NODE,
	.prompt = "",
	.config_write = mgmt_debug_fe_client_config_write,
};

/*
 * Initialize library and try connecting with MGMTD.
 */
struct mgmt_fe_client *mgmt_fe_client_create(const char *client_name,
					     struct mgmt_fe_client_cbs *cbs,
					     uintptr_t user_data,
					     struct event_loop *event_loop)
{
	struct mgmt_fe_client *client =
		XCALLOC(MTYPE_MGMTD_FE_CLIENT, sizeof(*client));

	client->name = XSTRDUP(MTYPE_MGMTD_FE_CLIENT_NAME, client_name);
	client->user_data = user_data;
	if (cbs)
		client->cbs = *cbs;

	mgmt_sessions_init(&client->sessions);

	msg_client_init(&client->client, event_loop, MGMTD_FE_SERVER_PATH,
			mgmt_fe_client_notify_connect,
			mgmt_fe_client_notify_disconnect,
			mgmt_fe_client_process_msg, MGMTD_FE_MAX_NUM_MSG_PROC,
			MGMTD_FE_MAX_NUM_MSG_WRITE, MGMTD_FE_MSG_MAX_LEN, true,
			"FE-client", MGMTD_DBG_FE_CLIENT_CHECK());

	MGMTD_FE_CLIENT_DBG("Initialized client '%s'", client_name);

	return client;
}

void mgmt_fe_client_lib_vty_init(void)
{
	debug_init(&mgmt_dbg_fe_client_cbs);
	install_node(&mgmt_dbg_node);
	install_element(ENABLE_NODE, &debug_mgmt_client_fe_cmd);
	install_element(CONFIG_NODE, &debug_mgmt_client_fe_cmd);
}

uint mgmt_fe_client_session_count(struct mgmt_fe_client *client)
{
	return mgmt_sessions_count(&client->sessions);
}

/*
 * Create a new Session for a Frontend Client connection.
 */
enum mgmt_result mgmt_fe_create_client_session(struct mgmt_fe_client *client,
					       uint64_t client_id,
					       uintptr_t user_ctx)
{
	struct mgmt_fe_client_session *session;

	session = XCALLOC(MTYPE_MGMTD_FE_SESSION,
			  sizeof(struct mgmt_fe_client_session));
	assert(session);
	session->user_ctx = user_ctx;
	session->client_id = client_id;
	session->client = client;
	session->session_id = 0;

	mgmt_sessions_add_tail(&client->sessions, session);

	if (mgmt_fe_send_session_req(client, session, true) != 0) {
		XFREE(MTYPE_MGMTD_FE_SESSION, session);
		return MGMTD_INTERNAL_ERROR;
	}

	return MGMTD_SUCCESS;
}

/*
 * Delete an existing Session for a Frontend Client connection.
 */
enum mgmt_result mgmt_fe_destroy_client_session(struct mgmt_fe_client *client,
						uint64_t client_id)
{
	struct mgmt_fe_client_session *session;

	session = mgmt_fe_find_session_by_client_id(client, client_id);
	if (!session || session->client != client)
		return MGMTD_INVALID_PARAM;

	if (session->session_id &&
	    mgmt_fe_send_session_req(client, session, false) != 0)
		MGMTD_FE_CLIENT_ERR(
			"Failed to send session destroy request for the session-id %" PRIu64,
			session->session_id);

	mgmt_sessions_del(&client->sessions, session);
	XFREE(MTYPE_MGMTD_FE_SESSION, session);

	return MGMTD_SUCCESS;
}

/*
 * Destroy library and cleanup everything.
 */
void mgmt_fe_client_destroy(struct mgmt_fe_client *client)
{
	struct mgmt_fe_client_session *session;

	MGMTD_FE_CLIENT_DBG("Destroying MGMTD Frontend Client '%s'",
			    client->name);

	FOREACH_SESSION_IN_LIST (client, session)
		mgmt_fe_destroy_client_session(client, session->client_id);

	msg_client_cleanup(&client->client);

	XFREE(MTYPE_MGMTD_FE_CLIENT_NAME, client->name);
	XFREE(MTYPE_MGMTD_FE_CLIENT, client);
}