mcast_set_ttl.c

来自「Unix网络编程 基于Socket的网络编程」· C语言 代码 · 共 37 行

#include	"unp.h"

int
mcast_set_ttl(int sockfd, int val)
{
	switch (sockfd_to_family(sockfd)) {
	case AF_INET: {
		u_char		ttl;

		ttl = val;
		return(setsockopt(sockfd, IPPROTO_IP, IP_MULTICAST_TTL,
						  &ttl, sizeof(ttl)));
	}

#ifdef	IPV6
	case AF_INET6: {
		int		hop;

		hop = val;
		return(setsockopt(sockfd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS,
						  &hop, sizeof(hop)));
	}
#endif

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

void
Mcast_set_ttl(int sockfd, int val)
{
	if (mcast_set_ttl(sockfd, val) < 0)
		err_sys("mcast_set_ttl error");
}