#include    <errno.h>

#include    <net/if.h>

#include    <sys/socket.h>

#define     SA    struct sockaddr

int mcast_join_source_group(int sockfd, const SA *src,

    socklen_t srclen,const SA *grp, socklen_t grplen,

    const char *ifname, u_int ifindex)

{

#ifdef MCAST_JOIN_SOURCE_GROUP

    struct group_source_req req;

    if (ifindex > ) {

        req.gsr_interface = ifindex;

    } else if (ifname != NULL) {

        if ( (req.gsr_interface = if_nametoindex(ifname)) == ) {

            errno = ENXIO;    /* i/f name not found */

            return(-);

        }

    } else {

        req.gsr_interface = ;

    }

    if (grplen > sizeof(req.gsr_group) ||

        srclen > sizeof(req.gsr_source)) {

        errno = EINVAL;

        return -;

    }

    memcpy(&req.gsr_group, grp, grplen);

    memcpy(&req.gsr_source, src, srclen);

    return (setsockopt(sockfd, family_to_level(grp->sa_family),

            MCAST_JOIN_SOURCE_GROUP, &req, sizeof(req)));

#else

    switch (grp->sa_family) {

#ifdef IP_ADD_SOURCE_MEMBERSHIP

        case AF_INET: {

            struct ip_mreq_source    mreq;

            struct ifreq            ifreq;

            memcpy(&mreq.imr_multiaddr,

               &((struct sockaddr_in *) grp)->sin_addr,

               sizeof(struct in_addr));

            memcpy(&mreq.imr_sourceaddr,

               &((struct sockaddr_in *) src)->sin_addr,

               sizeof(struct in_addr));

            if (ifindex > ) {

                if (if_indextoname(ifindex, ifreq.ifr_name) == NULL) {

                    errno = ENXIO;    /* i/f index not found */

                    return(-);

                }

                goto doioctl;

            } else if (ifname != NULL) {

                strncpy(ifreq.ifr_name, ifname, IFNAMSIZ);

                doioctl:

                if (ioctl(sockfd, SIOCGIFADDR, &ifreq) < ) {

                    return(-);

                }

                memcpy(&mreq.imr_interface,

                   &((struct sockaddr_in *) &ifreq.ifr_addr)->sin_addr,

                   sizeof(struct in_addr));

            } else {

                mreq.imr_interface.s_addr = htonl(INADDR_ANY);

            }

            return(setsockopt(sockfd, IPPROTO_IP,

                IP_ADD_SOURCE_MEMBERSHIP,&mreq, sizeof(mreq)));

        }

#endif

#ifdef    IPV6

        /* IPv6 source-specific API is MCAST_JOIN_SOURCE_GROUP */

        case AF_INET6: {}

#endif

        default: {

            errno = EAFNOSUPPORT;

            return(-);

        }

    }

#endif

}