net/netfilter/nf_sockopt.c
  1.  int nf_getsockopt(struct sock *sk, int pf, int val, char __user *opt, int *len)
    2. 

  2.  {
    3. 

  3.      return nf_sockopt(sk, pf, val, opt, len, 1);
    4. 

  4.  }
    5. 

  5.  EXPORT_SYMBOL(nf_getsockopt);