if_addmulti
error = if_addmulti(ifp, &ifr->ifr_addr, &ifma);
int if_addmulti(struct ifnet *, struct sockaddr *, struct ifmultiaddr **);
error = if_addmulti(ifp, (struct sockaddr *)&sdl, &rifma);
error = if_addmulti(ifp, (struct sockaddr *)&sdl, &rifma);
error = if_addmulti(ifp_p, (struct sockaddr *)&sdl, NULL);
error = if_addmulti(priv->ifp,
error = if_addmulti(ifp, (struct sockaddr *)&sdl, &rifma);
error = if_addmulti(ifp, (struct sockaddr *)&sin, &ifma);
*errorp = if_addmulti(ifp, (struct sockaddr *)&sin6, &ifma);