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IPSEC_GOODMASK(3)          Library Functions Manual          IPSEC_GOODMASK(3)



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 <&lt;freeswan.h>&gt;

       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)