NAME
ipsec_rangetosubnet - convert address range to subnet
SYNOPSIS
#include <freeswan.h>
const char *rangetosubnet(const ip_address * start,
const ip_address * stop, ip_subnet * dst);
DESCRIPTION
Rangetosubnet accepts two IP addresses which define an address range,
from start to stop inclusive, and converts this to a subnet if
possible. The addresses must both be IPv4 or both be IPv6, and the
address family of the resulting subnet is the same.
Rangetosubnet returns NULL for success and a pointer to a
string-literal error message for failure; see DIAGNOSTICS.
SEE ALSO
ipsec_initsubnet(3), ipsec_ttosubnet(3)
DIAGNOSTICS
Fatal errors in rangetosubnet are: mixed address families; unknown
address family; start and stop do not define a subnet.
HISTORY
Written for the FreeS/WAN project by Henry Spencer.
BUGS
The restriction of error reports to literal strings (so that callers
don´t need to worry about freeing them or copying them) does limit the
precision of error reporting.
The error-reporting convention lends itself to slightly obscure code,
because many readers will not think of NULL as signifying success. A
good way to make it clearer is to write something like:
const char *error;
error = rangetosubnet( /* ... */ );
if (error != NULL) {
/* something went wrong */