NAME
ipsec_atoasr - convert ASCII to Internet address, subnet, or range
ipsec rangetoa - 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 */
11 June 2001