Content-type: text/html Manpage of IPSEC_GOODMASK

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IPSEC_GOODMASK

Section: C Library Functions (3)
Updated: 13 Oct 1998
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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

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.

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.

This document was created by man2html, using the manual pages.
Time: 04:38:15 GMT, May 22, 2000