/*
 * BFD daemon code
 * Copyright (C) 2018 Network Device Education Foundation, Inc. ("NetDEF")
 *
 * FRR is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2, or (at your option) any
 * later version.
 *
 * FRR is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with FRR; see the file COPYING.  If not, write to the Free
 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 * 02111-1307, USA.
 */

#include <zebra.h>

#include "bfd.h"
#include "lib/version.h"


/*
 * FRR related code.
 */
DEFINE_MGROUP(BFDD, "Bidirectional Forwarding Detection Daemon");
DEFINE_MTYPE(BFDD, BFDD_TMP, "short-lived temporary memory");
DEFINE_MTYPE(BFDD, BFDD_CONFIG, "long-lived configuration memory");
DEFINE_MTYPE(BFDD, BFDD_LABEL, "long-lived label memory");
DEFINE_MTYPE(BFDD, BFDD_CONTROL, "long-lived control socket memory");
DEFINE_MTYPE(BFDD, BFDD_NOTIFICATION, "short-lived control notification data");

/* Master of threads. */
struct thread_master *master;

/* BFDd privileges */
static zebra_capabilities_t _caps_p[] = {ZCAP_BIND};

struct zebra_privs_t bfdd_privs = {
#if defined(FRR_USER) && defined(FRR_GROUP)
	.user = FRR_USER,
	.group = FRR_GROUP,
#endif
#if defined(VTY_GROUP)
	.vty_group = VTY_GROUP,
#endif
	.caps_p = _caps_p,
	.cap_num_p = array_size(_caps_p),
	.cap_num_i = 0,
};

void socket_close(int *s)
{
	if (*s <= 0)
		return;

	if (close(*s) != 0)
		log_error("%s: close(%d): (%d) %s", __func__, *s, errno,
			  strerror(errno));

	*s = -1;
}

static void sigusr1_handler(void)
{
	zlog_rotate();
}

static void sigterm_handler(void)
{
	/* Signalize shutdown. */
	frr_early_fini();

	/* Stop receiving message from zebra. */
	bfdd_zclient_stop();

	/* Shutdown controller to avoid receiving anymore commands. */
	control_shutdown();

	/* Shutdown and free all protocol related memory. */
	bfd_shutdown();

	/* Close all descriptors. */
	socket_close(&bglobal.bg_echo);
	socket_close(&bglobal.bg_shop);
	socket_close(&bglobal.bg_mhop);
	socket_close(&bglobal.bg_shop6);
	socket_close(&bglobal.bg_mhop6);

	/* Terminate and free() FRR related memory. */
	frr_fini();

	exit(0);
}

static struct quagga_signal_t bfd_signals[] = {
	{
		.signal = SIGUSR1,
		.handler = &sigusr1_handler,
	},
	{
		.signal = SIGTERM,
		.handler = &sigterm_handler,
	},
	{
		.signal = SIGINT,
		.handler = &sigterm_handler,
	},
};

FRR_DAEMON_INFO(bfdd, BFD, .vty_port = 2617,
		.proghelp = "Implementation of the BFD protocol.",
		.signals = bfd_signals, .n_signals = array_size(bfd_signals),
		.privs = &bfdd_privs)

#define OPTION_CTLSOCK 1001
static struct option longopts[] = {
	{"bfdctl", required_argument, NULL, OPTION_CTLSOCK},
	{0}
};


/*
 * BFD daemon related code.
 */
struct bfd_global bglobal;

struct bfd_diag_str_list diag_list[] = {
	{.str = "control-expired", .type = BD_CONTROL_EXPIRED},
	{.str = "echo-failed", .type = BD_ECHO_FAILED},
	{.str = "neighbor-down", .type = BD_NEIGHBOR_DOWN},
	{.str = "forwarding-reset", .type = BD_FORWARDING_RESET},
	{.str = "path-down", .type = BD_PATH_DOWN},
	{.str = "concatenated-path-down", .type = BD_CONCATPATH_DOWN},
	{.str = "administratively-down", .type = BD_ADMIN_DOWN},
	{.str = "reverse-concat-path-down", .type = BD_REVCONCATPATH_DOWN},
	{.str = NULL},
};

struct bfd_state_str_list state_list[] = {
	{.str = "admin-down", .type = PTM_BFD_ADM_DOWN},
	{.str = "down", .type = PTM_BFD_DOWN},
	{.str = "init", .type = PTM_BFD_INIT},
	{.str = "up", .type = PTM_BFD_UP},
	{.str = NULL},
};


static void bg_init(void)
{
	TAILQ_INIT(&bglobal.bg_bcslist);

	bglobal.bg_shop = bp_udp_shop();
	bglobal.bg_mhop = bp_udp_mhop();
	bglobal.bg_shop6 = bp_udp6_shop();
	bglobal.bg_mhop6 = bp_udp6_mhop();
	bglobal.bg_echo = bp_echo_socket();
	bglobal.bg_echov6 = bp_echov6_socket();
}

int main(int argc, char *argv[])
{
	const char *ctl_path = BFDD_CONTROL_SOCKET;
	int opt;

	frr_preinit(&bfdd_di, argc, argv);
	frr_opt_add("", longopts,
		    "      --bfdctl       Specify bfdd control socket\n");

	while (true) {
		opt = frr_getopt(argc, argv, NULL);
		if (opt == EOF)
			break;

		switch (opt) {
		case OPTION_CTLSOCK:
			ctl_path = optarg;
			break;

		default:
			frr_help_exit(1);
			break;
		}
	}

#if 0 /* TODO add support for JSON configuration files. */
	parse_config(conf);
#endif

	/* Initialize logging API. */
	log_init(1, BLOG_DEBUG, &bfdd_di);

	/* Initialize system sockets. */
	bg_init();

	/* Initialize control socket. */
	control_init(ctl_path);

	/* Initialize FRR infrastructure. */
	master = frr_init();

	/* Initialize BFD data structures. */
	bfd_initialize();

	/* Initialize zebra connection. */
	bfdd_zclient_init(&bfdd_privs);

	/* Add descriptors to the event loop. */
	thread_add_read(master, bfd_recv_cb, NULL, bglobal.bg_shop,
			&bglobal.bg_ev[0]);
	thread_add_read(master, bfd_recv_cb, NULL, bglobal.bg_mhop,
			&bglobal.bg_ev[1]);
	thread_add_read(master, bfd_recv_cb, NULL, bglobal.bg_shop6,
			&bglobal.bg_ev[2]);
	thread_add_read(master, bfd_recv_cb, NULL, bglobal.bg_mhop6,
			&bglobal.bg_ev[3]);
	thread_add_read(master, bfd_recv_cb, NULL, bglobal.bg_echo,
			&bglobal.bg_ev[4]);
	thread_add_read(master, bfd_recv_cb, NULL, bglobal.bg_echov6,
			&bglobal.bg_ev[5]);
	thread_add_read(master, control_accept, NULL, bglobal.bg_csock,
			&bglobal.bg_csockev);

	/* Install commands. */
	bfdd_vty_init();

	/* read configuration file and daemonize  */
	frr_config_fork();

	frr_run(master);
	/* NOTREACHED */

	return 0;
}