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)