---
name: "ipsec_atoasr"
section: "3"
platform: "linux"
package: "openswan"
version: "1:2.6.37-3+deb7u1"
release: "Debian 7 (Wheezy)"
platforms: ["linux"]
url: "https://new.carta.tech/ipsec_atoasr"
---

# ipsec\_atoasr(3)

convert ASCII to Internet address, subnet, or range, convert Internet address range to ASCII

## 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)](/ipsec_addrtoa/3.md) and [*ipsec\_subnettoa*(3)](/ipsec_subnettoa/3.md)).

A single address can be any form acceptable to [*ipsec\_atoaddr*(3)](/ipsec_atoaddr/3.md): dotted decimal, DNS name, or hexadecimal number. A subnet specification uses the form *network***/***mask* interpreted by [*ipsec\_atosubnet*(3)](/ipsec_atosubnet/3.md).

An address range is two [*ipsec\_atoaddr*(3)](/ipsec_atoaddr/3.md) 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_atoaddr/3.md), [ipsec\_atosubnet(3)](/ipsec_atosubnet/3.md)

## DIAGNOSTICS

Fatal errors in *atoasr* are: empty input; error in [*ipsec\_atoaddr*(3)](/ipsec_atoaddr/3.md) or [*ipsec\_atosubnet*(3)](/ipsec_atosubnet/3.md) 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 */
```