inet_net_pton.c

/*	$OpenBSD: inet_net_pton.c,v 1.14 2022/12/27 17:10:06 jmc Exp $	*/

/*
 * Copyright (c) 2012 by Gilles Chehade <[email protected]>
 * Copyright (c) 1996,1999 by Internet Software Consortium.
 *
 * SPDX-License-Identifier: ISC
 *
 * 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 "port_before.h"

#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>

#include "port_after.h"

static int	inet_net_pton_ipv4(const char *, u_char *, size_t);
static int	inet_net_pton_ipv6(const char *, u_char *, size_t);

/*
 * 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));
	case AF_INET6:
		return (inet_net_pton_ipv6(src, dst, size));
	default:
		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",
		digits[] = "0123456789";
	int n, ch, tmp, dirty, bits;
	const u_char *odst = dst;

	ch = (unsigned char)*src++;
	if (ch == '0' && (src[0] == 'x' || src[0] == 'X')
	    && isascii((unsigned char)src[1]) && isxdigit((unsigned char)src[1])) {
		/* Hexadecimal: Eat nybble string. */
		if (size == 0)
			goto emsgsize;
		tmp = 0, dirty = 0;
		src++;	/* skip x or X. */
		while ((ch = (unsigned char)*src++) != '\0' &&
		    isascii(ch) && isxdigit(ch)) {
			if (isupper(ch))
				ch = tolower(ch);
			n = strchr(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 = strchr(digits, ch) - digits;
				assert(n >= 0 && n <= 9);
				tmp *= 10;
				tmp += n;
				if (tmp > 255)
					goto enoent;
			} while ((ch = (unsigned char)*src++) != '\0' &&
				 isascii(ch) && isdigit(ch));
			if (size-- == 0)
				goto emsgsize;
			*dst++ = (u_char) tmp;
			if (ch == '\0' || ch == '/')
				break;
			if (ch != '.')
				goto enoent;
			ch = (unsigned char)*src++;
			if (!isascii(ch) || !isdigit(ch))
				goto enoent;
		}
	} else
		goto enoent;

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

	/* 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 < ((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:
	errno = ENOENT;
	return (-1);

 emsgsize:
	errno = EMSGSIZE;
	return (-1);
}


static int
inet_net_pton_ipv6(const char *src, u_char *dst, size_t size)
{
	struct in6_addr	 in6;
	int		 ret;
	int		 bits;
	size_t		 bytes;
	char		 buf[INET6_ADDRSTRLEN + sizeof("/128")];
	char		*sep;
	const char	*errstr;

	if (strlcpy(buf, src, sizeof buf) >= sizeof buf) {
		errno = EMSGSIZE;
		return (-1);
	}

	sep = strchr(buf, '/');
	if (sep != NULL)
		*sep++ = '\0';

	ret = inet_pton(AF_INET6, buf, &in6);
	if (ret != 1)
		return (-1);

	if (sep == NULL)
		bits = 128;
	else {
		bits = strtonum(sep, 0, 128, &errstr);
		if (errstr) {
			errno = EINVAL;
			return (-1);
		}
	}

	bytes = (bits + 7) / 8;
	if (bytes > size) {
		errno = EMSGSIZE;
		return (-1);
	}
	memcpy(dst, &in6.s6_addr, bytes);
	return (bits);
}

/*
 * Weak aliases for applications that use certain private entry points,
 * and fail to include <arpa/inet.h>.
 */
#undef inet_net_pton
__weak_reference(__inet_net_pton, inet_net_pton);