NAME¶
ipsec_atoasr, ipsec_rangetoa - convert ASCII to Internet address, subnet, or
range, convert Internet address range to ASCII
SYNOPSIS¶
#include <freeswan.h>
const char *atoasr(const char *src, size_t srclen, char *type, struct
in_addr *addrs);
size_t rangetoa(struct in_addr *addrs, int format, char *dst, size_t
dstlen);
DESCRIPTION¶
These functions are obsolete; there is no current equivalent, because so far
they have not proved useful.
Atoasr converts an ASCII address, subnet, or address range into a
suitable combination of binary addresses (in network byte order).
Rangetoa converts an address range back into ASCII, using
dotted-decimal form for the addresses (the other reverse conversions are
handled by
ipsec_addrtoa(3) and
ipsec_subnettoa(3)).
A single address can be any form acceptable to
ipsec_atoaddr(3): dotted
decimal, DNS name, or hexadecimal number. A subnet specification uses the form
network/mask interpreted by
ipsec_atosubnet(3).
An address range is two
ipsec_atoaddr(3) addresses separated by a
... delimiter. If there are four dots rather than three, the first is
taken as part of the begin address, e.g. for a complete DNS name which ends
with
. to suppress completion attempts. The begin address of a range
must be less than or equal to the end address.
The
srclen parameter of
atoasr specifies the length of the ASCII
string pointed to by
src; it is an error for there to be anything else
(e.g., a terminating NUL) within that length. As a convenience for cases where
an entire NUL-terminated string is to be converted, a
srclen value of
0 is taken to mean
strlen(src).
The
type parameter of
atoasr must point to a
char variable
used to record which form was found. The
addrs parameter must point to
a two-element array of
struct in_addr which receives the results. The
values stored into
*type, and the corresponding values in the array,
are:
*type addrs[0] addrs[1]
address
'a' address -
subnet
's' network mask
range
'r' begin end
The
dstlen parameter of
rangetoa specifies the size of the
dst parameter; under no circumstances are more than
dstlen bytes
written to
dst. A result which will not fit is truncated.
Dstlen
can be zero, in which case
dst need not be valid and no result is
written, but the return value is unaffected; in all other cases, the (possibly
truncated) result is NUL-terminated. The
freeswan.h header file defines
a constant,
RANGETOA_BUF, which is the size of a buffer just large
enough for worst-case results.
The
format parameter of
rangetoa specifies what format is to be
used for the conversion. The value
0 (not the ASCII character
'0', but a zero value) specifies a reasonable default, and is in fact
the only format currently available. This parameter is a hedge against future
needs.
Atoasr returns NULL for success and a pointer to a string-literal error
message for failure; see DIAGNOSTICS.
Rangetoa returns
0 for a
failure, and otherwise always returns the size of buffer which would be needed
to accommodate the full conversion result, including terminating NUL; it is
the caller's responsibility to check this against the size of the provided
buffer to determine whether truncation has occurred.
SEE ALSO¶
ipsec_atoaddr(3),
ipsec_atosubnet(3)
DIAGNOSTICS¶
Fatal errors in
atoasr are: empty input; error in
ipsec_atoaddr(3)
or
ipsec_atosubnet(3) during conversion; begin address of range exceeds
end address.
Fatal errors in
rangetoa are: unknown format.
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 = atoasr( /* ... */ );
if (error != NULL) {
/* something went wrong */
