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NAME

       ipsec_goodmask - is this Internet subnet mask a valid one?
       ipsec masktobits - convert Internet subnet mask to bit count
       ipsec bitstomask - convert bit count to Internet subnet mask

SYNOPSIS

       #include <freeswan.h>

       int goodmask(struct in_addr mask);
       int masktobits(struct in_addr mask);
       struct in_addr bitstomask(int n);

DESCRIPTION

       These  functions  are  obsolete; see ipsec_masktocount(3) for a partial
       replacement.

       Goodmask reports whether the subnet mask is a valid one, i.e.  consists
       of  a  (possibly  empty)  sequence of 1s followed by a (possibly empty)
       sequence of 0s.  Masktobits takes a (valid) subnet mask and returns the
       number of 1 bits in it.  Bitstomask reverses this, returning the subnet
       mask corresponding to bit count n.

       All masks are in network byte order.

SEE ALSO

       inet(3), ipsec_atosubnet(3)

DIAGNOSTICS

       Masktobits returns -1 for an invalid mask.  Bitstomask returns an  all-
       zeros mask for a negative or out-of-range n.

HISTORY

       Written for the FreeS/WAN project by Henry Spencer.

BUGS

       The  error-reporting  convention of bitstomask is less than ideal; zero
       is sometimes a legitimate mask.

                                 11 June 2001                IPSEC_GOODMASK(3)