mcast_leave.c

Unix网络编程 基于Socket的网络编程

#include	"unp.h"

int
mcast_leave(int sockfd, const SA *sa, socklen_t salen)
{
	switch (sa->sa_family) {
	case AF_INET: {
		struct ip_mreq		mreq;

		memcpy(&mreq.imr_multiaddr,
			   &((struct sockaddr_in *) sa)->sin_addr,
			   sizeof(struct in_addr));
		mreq.imr_interface.s_addr = htonl(INADDR_ANY);
		return(setsockopt(sockfd, IPPROTO_IP, IP_DROP_MEMBERSHIP,
						  &mreq, sizeof(mreq)));
	}

#ifdef	IPV6
	case AF_INET6: {
		struct ipv6_mreq	mreq6;

		memcpy(&mreq6.ipv6mr_multiaddr,
			   &((struct sockaddr_in6 *) sa)->sin6_addr,
			   sizeof(struct in6_addr));
		mreq6.ipv6mr_interface = 0;
		return(setsockopt(sockfd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP,
						  &mreq6, sizeof(mreq6)));
	}
#endif

	default:
		errno = EPROTONOSUPPORT;
		return(-1);
	}
}

void
Mcast_leave(int sockfd, const SA *sa, socklen_t salen)
{
	if (mcast_leave(sockfd, sa, salen) < 0)
		err_sys("mcast_leave error");
}