NAME¶
ipsec_goodmask, ipsec_masktobits, ipsec_bitstomask - check if Internet subnet
mask is valid, convert Internet subnet mask to bit count, 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.
