extern int ip_mc_gsfget(struct sock *sk, struct group_filter *gsf,
struct group_filter __user *optval, int __user *optlen);
extern int ip_mc_sf_allow(struct sock *sk, __be32 local, __be32 rmt, int dif);
extern int ip_mc_gsfget(struct sock *sk, struct group_filter *gsf,
struct group_filter __user *optval, int __user *optlen);
extern int ip_mc_sf_allow(struct sock *sk, __be32 local, __be32 rmt, int dif);