/*
 * Copyright (c) 2001,2002 Sebastien Petit <spe@bsdfr.org>
 *
 * Redistribution and use in source forms, with and without modification,
 * are permitted provided that the following conditions are met:
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution. Obviously, it
 *    would be nice if you gave credit where credit is due but requiring it
 *    would be too onerous.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by Sebastien Petit.
 * 4. Neither the name of its contributors may be used to endorse or promote
 *    products derived from this software without specific prior written
 *    permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $Id: vrrp_multicast.c,v 1.1 2017/06/14 12:01:54 misho Exp $
 */

#include <errno.h>
#include "vrrp_multicast.h"

/* join multicast group with ip address */
char 
vrrp_multicast_join_group(int sd, u_char * multicast_ip, struct in_addr * interface_ip)
{
	struct ip_mreq  imr;

	bzero(&imr, sizeof(imr));
	imr.imr_multiaddr.s_addr = inet_addr(multicast_ip);
	imr.imr_interface.s_addr = interface_ip->s_addr;
	if (setsockopt(sd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &imr, sizeof(imr)) == -1) {
		syslog(LOG_ERR, "cannot join multicast group %s with ip source %s [ IP_ADD_MEMBERSHIP ]", multicast_ip, inet_ntoa(*interface_ip));
		return -1;
	}
	return 0;
}

/* Set multicast ttl IP */
char 
vrrp_multicast_set_ttl(int sd, u_char ttl)
{
	if (setsockopt(sd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl)) == -1) {
		syslog(LOG_ERR, "cannot set multicast TTL: %s", strerror(errno));
		return -1;
	}
	return 0;
}

char 
vrrp_multicast_set_if(int sd, struct in_addr * addr, char *if_name)
{
	if (setsockopt(sd, IPPROTO_IP, IP_MULTICAST_IF, addr, sizeof(*addr)) == -1) {
		syslog(LOG_ERR, "cannot setsockopt IP_MULTICAST_IF on primary address of %s: %s", if_name, strerror(errno));
		return -1;
	}
	return 0;
}

int vrrp_multicast_set_loopback(int sd, u_char flag) {
	if (setsockopt(sd, IPPROTO_IP, IP_MULTICAST_LOOP, &flag, sizeof(flag)) == -1) {
		syslog(LOG_ERR, "cannot setsockopt IP_MULTICAST_LOOP: %s", strerror(errno));
		return -1;
	}

	return 0;
}

/* Open VRRP socket and join multicast group */
char 
vrrp_multicast_set_socket(struct vrrp_vr * vr)
{
	if (vrrp_multicast_join_group(vr->sd, VRRP_MULTICAST_IP, (struct in_addr *) & vr->vr_if->ip_addrs[0]) == -1) {
		close(vr->sd);
		return -1;
	}
	if (vrrp_multicast_set_ttl(vr->sd, VRRP_MULTICAST_TTL) == -1) {
		close(vr->sd);
		return -1;
	}
	/* XXX don't need to force interface for multicast. Let the kernel
	 * choose by itself. this setsockopt doesn't work with ipsec/ah...
	 * don't know why */
	if (vrrp_multicast_set_if(vr->sd, &vr->vr_if->ip_addrs[0], vr->vr_if->if_name) == -1) {
		close(vr->sd);
		return -1;
	}
	if (vrrp_multicast_set_loopback(vr->sd, VRRP_MULTICAST_DISABLE_LOOPBACK) == -1) {
		close(vr->sd);
		return -1;
	}

	return 0;
}

char 
vrrp_multicast_open_socket(struct vrrp_vr * vr)
{
	if (vrrp_network_open_socket(vr) == -1)
		return -1;
	if (vrrp_multicast_set_socket(vr) == -1)
		return -1;

	return 0;
}