socket_mcjoin6.c

It support IPv4 and IPv6 unicast and multicast and contains a trivial sender and a trivial receiver

#include <sys/types.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include "socket.h"
#include "byte.h"
#include "haveip6.h"
#include "ip6.h"
#include "error.h"

#ifndef IPV6_ADD_MEMBERSHIP
#ifdef IPV6_JOIN_GROUP
#define IPV6_ADD_MEMBERSHIP IPV6_JOIN_GROUP
#else
#undef LIBC_HAS_IP6
#endif
#endif

int socket_mcjoin6(int s,const char ip[16],int interface)
{
#ifdef LIBC_HAS_IP6
  struct ipv6_mreq opt;
#endif
  if (ip6_isv4mapped(ip))
    return socket_mcjoin4(s,ip+12,ip);
#ifdef LIBC_HAS_IP6
  byte_copy(&opt.ipv6mr_multiaddr,16,ip);
  opt.ipv6mr_interface=interface;
  return setsockopt(s,IPPROTO_IPV6,IPV6_ADD_MEMBERSHIP,&opt,sizeof opt);
#else
  errno=error_proto;
  return -1;
#endif
}