MCAST_BLOCK_SOURCE,&req,sizeof(req)));#elseswitch(grp->sa_family) { #ifdef IP_BLOCK_SOURCEcaseAF_INET: {structip_mreq_source mreq; memcpy(&mreq.imr_multiaddr,&((structsockaddr_in *) grp)->sin_addr,sizeof(structin_addr)); memcpy(&mreq.imr_sourceaddr,&((structsockaddr_in *) src)...