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Manpage of IPSEC_GOODMASK
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.
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.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- SEE ALSO
-
- DIAGNOSTICS
-
- HISTORY
-
- BUGS
-
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