glibc/resolv/inet_net_pton.c

/*
 * Copyright (c) 1996,1999 by Internet Software Consortium.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 * SOFTWARE.
 */

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#ifdef SPRINTF_CHAR
# define SPRINTF(x) strlen(sprintf/**/x)
#else
# define SPRINTF(x) ((size_t)sprintf x)
#endif

static int	inet_net_pton_ipv4 (const char *src, u_char *dst,
				    size_t size) __THROW;

/*
 * static int
 * inet_net_pton(af, src, dst, size)
 *	convert network number from presentation to network format.
 *	accepts hex octets, hex strings, decimal octets, and /CIDR.
 *	"size" is in bytes and describes "dst".
 * return:
 *	number of bits, either imputed classfully or specified with /CIDR,
 *	or -1 if some failure occurred (check errno).  ENOENT means it was
 *	not a valid network specification.
 * author:
 *	Paul Vixie (ISC), June 1996
 */
int
inet_net_pton (int af, const char *src, void *dst, size_t size)
{
	switch (af) {
	case AF_INET:
		return (inet_net_pton_ipv4(src, dst, size));
	default:
		__set_errno (EAFNOSUPPORT);
		return (-1);
	}
}

/*
 * static int
 * inet_net_pton_ipv4(src, dst, size)
 *	convert IPv4 network number from presentation to network format.
 *	accepts hex octets, hex strings, decimal octets, and /CIDR.
 *	"size" is in bytes and describes "dst".
 * return:
 *	number of bits, either imputed classfully or specified with /CIDR,
 *	or -1 if some failure occurred (check errno).  ENOENT means it was
 *	not an IPv4 network specification.
 * note:
 *	network byte order assumed.  this means 192.5.5.240/28 has
 *	0b11110000 in its fourth octet.
 * author:
 *	Paul Vixie (ISC), June 1996
 */
static int
inet_net_pton_ipv4 (const char *src, u_char *dst, size_t size)
{
	static const char xdigits[] = "0123456789abcdef";
	int n, ch, tmp, dirty, bits;
	const u_char *odst = dst;

	ch = *src++;
	if (ch == '0' && (src[0] == 'x' || src[0] == 'X')
	    && isascii(src[1]) && isxdigit(src[1])) {
		/* Hexadecimal: Eat nybble string. */
		if (size <= 0)
			goto emsgsize;
		dirty = 0;
		tmp = 0;	/* To calm down gcc.  */
		src++;	/* skip x or X. */
		while (isxdigit((ch = *src++))) {
			ch = _tolower(ch);
			n = (const char *) __rawmemchr(xdigits, ch) - xdigits;
			assert(n >= 0 && n <= 15);
			if (dirty == 0)
				tmp = n;
			else
				tmp = (tmp << 4) | n;
			if (++dirty == 2) {
				if (size-- <= 0)
					goto emsgsize;
				*dst++ = (u_char) tmp;
				dirty = 0;
			}
		}
		if (dirty) {  /* Odd trailing nybble? */
			if (size-- <= 0)
				goto emsgsize;
			*dst++ = (u_char) (tmp << 4);
		}
	} else if (isascii(ch) && isdigit(ch)) {
		/* Decimal: eat dotted digit string. */
		for (;;) {
			tmp = 0;
			do {
				n = ((const char *) __rawmemchr(xdigits, ch)
				     - xdigits);
				assert(n >= 0 && n <= 9);
				tmp *= 10;
				tmp += n;
				if (tmp > 255)
					goto enoent;
			} while (isascii((ch = *src++)) && isdigit(ch));
			if (size-- <= 0)
				goto emsgsize;
			*dst++ = (u_char) tmp;
			if (ch == '\0' || ch == '/')
				break;
			if (ch != '.')
				goto enoent;
			ch = *src++;
			if (!isascii(ch) || !isdigit(ch))
				goto enoent;
		}
	} else
		goto enoent;

	bits = -1;
	if (ch == '/' && isascii(src[0]) && isdigit(src[0]) && dst > odst) {
		/* CIDR width specifier.  Nothing can follow it. */
		ch = *src++;	/* Skip over the /. */
		bits = 0;
		do {
			n = (const char *) __rawmemchr(xdigits, ch) - xdigits;
			assert(n >= 0 && n <= 9);
			bits *= 10;
			bits += n;
		} while (isascii((ch = *src++)) && isdigit(ch));
		if (ch != '\0')
			goto enoent;
		if (bits > 32)
			goto emsgsize;
	}

	/* Fiery death and destruction unless we prefetched EOS. */
	if (ch != '\0')
		goto enoent;

	/* If nothing was written to the destination, we found no address. */
	if (dst == odst)
		goto enoent;
	/* If no CIDR spec was given, infer width from net class. */
	if (bits == -1) {
		if (*odst >= 240)	/* Class E */
			bits = 32;
		else if (*odst >= 224)	/* Class D */
			bits = 4;
		else if (*odst >= 192)	/* Class C */
			bits = 24;
		else if (*odst >= 128)	/* Class B */
			bits = 16;
		else			/* Class A */
			bits = 8;
		/* If imputed mask is narrower than specified octets, widen. */
		if (bits >= 8 && bits < ((dst - odst) * 8))
			bits = (dst - odst) * 8;
	}
	/* Extend network to cover the actual mask. */
	while (bits > ((dst - odst) * 8)) {
		if (size-- <= 0)
			goto emsgsize;
		*dst++ = '\0';
	}
	return (bits);

 enoent:
	__set_errno (ENOENT);
	return (-1);

 emsgsize:
	__set_errno (EMSGSIZE);
	return (-1);
}