/*
 * This file contains code of the functions to add multicasting features to a
 * process
 */

#include "mcast.h"

/*
 * This function sets the socket option to make the local host join the
 * mulicast group
 */

void 
joinGroup(int s, char *group)
{
	struct sockaddr_in groupStruct;
	struct ip_mreq  mreq;	/* multicast group info structure */

	if ((groupStruct.sin_addr.s_addr = inet_addr(group)) == -1)
		printf("error in inet_addr\n");

	/* check if group address is indeed a Class D address */
	mreq.imr_multiaddr = groupStruct.sin_addr;
	mreq.imr_interface.s_addr = INADDR_ANY;

	if (setsockopt(s, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char *) &mreq,
		       sizeof(mreq)) == -1) {
		printf("error in joining group \n");
		exit(-1);
	}
}

/*
 * This function removes the process from the group
 */

void 
leaveGroup(int recvSock, char *group)
{
	struct sockaddr_in groupStruct;
	struct ip_mreq  dreq;	/* multicast group info structure */

	if ((groupStruct.sin_addr.s_addr = inet_addr(group)) == -1)
		printf("error in inet_addr\n");

	dreq.imr_multiaddr = groupStruct.sin_addr;
	dreq.imr_interface.s_addr = INADDR_ANY;

	if (setsockopt(recvSock, IPPROTO_IP, IP_DROP_MEMBERSHIP,
		       (char *) &dreq, sizeof(dreq)) == -1) {
		printf("error in leaving group \n");
		exit(-1);
	}
	printf("process quitting multicast group %s \n", group);
}


/*
 * This function sets a socket option that allows multipule processes to bind
 * to the same port
 */

void 
reusePort(int s)
{
	int             one = 1;

	if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (char *) &one, sizeof(one)) == -1) {
		printf("error in setsockopt,SO_REUSEPORT \n");
		exit(-1);
	}
}

/*
 * This function sets a socket option that allows multipule processes to bind
 * to the same port
 */

void 
displayDaddr(int s)
{
	int             one = 1;

	if (setsockopt(s, IPPROTO_IP, IP_RECVDSTADDR, (char *) &one, sizeof(one)) < 0)
		perror("IP_RECVDSTADDR setsockopt error");
}



/*
 * This function sets the Time-To-Live value
 */

void 
setTTLvalue(int s, u_char * ttl_value)
{
	if (setsockopt(s, IPPROTO_IP, IP_MULTICAST_TTL, (char *) ttl_value,
		       sizeof(u_char)) == -1) {
		printf("error in setting loopback value\n");
	}
}


/*
 * By default, messages sent to the multicast group are looped back to the local
 * host. this function disables that. loop = 1 /* means enable loopback loop
 * = 0 /* means disable loopback NOTE : by default, loopback is enabled */

void 
setLoopback(int s, u_char loop)
{
	if (setsockopt(s, IPPROTO_IP, IP_MULTICAST_LOOP, (char *) &loop,
		       sizeof(u_char)) == -1) {
		printf("error in disabling loopback\n");
	}
}