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inet_cidr_pton.c revision 1.2 
      1 /*	$NetBSD: inet_cidr_pton.c,v 1.2 2004/05/20 23:12:33 christos Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
      5  * Copyright (c) 1998,1999 by Internet Software Consortium.
      6  *
      7  * Permission to use, copy, modify, and distribute this software for any
      8  * purpose with or without fee is hereby granted, provided that the above
      9  * copyright notice and this permission notice appear in all copies.
     10  *
     11  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
     12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
     13  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
     14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
     15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
     16  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
     17  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
     18  */
     19 
     20 #include <sys/cdefs.h>
     21 #if defined(LIBC_SCCS) && !defined(lint)
     22 #if 0
     23 static const char rcsid[] = "Id: inet_cidr_pton.c,v 1.2.2.1.8.2 2004/03/17 00:29:46 marka Exp";
     24 #else
     25 __RCSID("$NetBSD: inet_cidr_pton.c,v 1.2 2004/05/20 23:12:33 christos Exp $");
     26 #endif
     27 #endif
     28 
     29 #include "port_before.h"
     30 
     31 #include "namespace.h"
     32 #include <sys/types.h>
     33 #include <sys/socket.h>
     34 #include <netinet/in.h>
     35 #include <arpa/nameser.h>
     36 #include <arpa/inet.h>
     37 
     38 #include <isc/assertions.h>
     39 #include <ctype.h>
     40 #include <errno.h>
     41 #include <stdio.h>
     42 #include <string.h>
     43 #include <stdlib.h>
     44 
     45 #include "port_after.h"
     46 
     47 #ifdef SPRINTF_CHAR
     48 # define SPRINTF(x) strlen(sprintf/**/x)
     49 #else
     50 # define SPRINTF(x) ((size_t)sprintf x)
     51 #endif
     52 
     53 #ifdef __weak_alias
     54 __weak_alias(inet_cidr_pton,_inet_cidr_pton)
     55 #endif
     56 
     57 static int	inet_cidr_pton_ipv4 __P((const char *src, u_char *dst,
     58 					 int *bits, int ipv6));
     59 static int	inet_cidr_pton_ipv6 __P((const char *src, u_char *dst,
     60 					 int *bits));
     61 
     62 static int	getbits(const char *, int ipv6);
     63 
     64 /*
     65  * int
     66  * inet_cidr_pton(af, src, dst, *bits)
     67  *	convert network address from presentation to network format.
     68  *	accepts inet_pton()'s input for this "af" plus trailing "/CIDR".
     69  *	"dst" is assumed large enough for its "af".  "bits" is set to the
     70  *	/CIDR prefix length, which can have defaults (like /32 for IPv4).
     71  * return:
     72  *	-1 if an error occurred (inspect errno; ENOENT means bad format).
     73  *	0 if successful conversion occurred.
     74  * note:
     75  *	192.5.5.1/28 has a nonzero host part, which means it isn't a network
     76  *	as called for by inet_net_pton() but it can be a host address with
     77  *	an included netmask.
     78  * author:
     79  *	Paul Vixie (ISC), October 1998
     80  */
     81 int
     82 inet_cidr_pton(int af, const char *src, void *dst, int *bits) {
     83 	switch (af) {
     84 	case AF_INET:
     85 		return (inet_cidr_pton_ipv4(src, dst, bits, 0));
     86 	case AF_INET6:
     87 		return (inet_cidr_pton_ipv6(src, dst, bits));
     88 	default:
     89 		errno = EAFNOSUPPORT;
     90 		return (-1);
     91 	}
     92 }
     93 
     94 static const char digits[] = "0123456789";
     95 
     96 static int
     97 inet_cidr_pton_ipv4(const char *src, u_char *dst, int *pbits, int ipv6) {
     98 	const u_char *odst = dst;
     99 	int n, ch, tmp, bits;
    100 	size_t size = 4;
    101 
    102 	/* Get the mantissa. */
    103 	while (ch = *src++, (isascii(ch) && isdigit(ch))) {
    104 		tmp = 0;
    105 		do {
    106 			n = strchr(digits, ch) - digits;
    107 			INSIST(n >= 0 && n <= 9);
    108 			tmp *= 10;
    109 			tmp += n;
    110 			if (tmp > 255)
    111 				goto enoent;
    112 		} while ((ch = *src++) != '\0' && isascii(ch) && isdigit(ch));
    113 		if (size-- == 0U)
    114 			goto emsgsize;
    115 		*dst++ = (u_char) tmp;
    116 		if (ch == '\0' || ch == '/')
    117 			break;
    118 		if (ch != '.')
    119 			goto enoent;
    120 	}
    121 
    122 	/* Get the prefix length if any. */
    123 	bits = -1;
    124 	if (ch == '/' && dst > odst) {
    125 		bits = getbits(src, ipv6);
    126 		if (bits == -2)
    127 			goto enoent;
    128 	} else if (ch != '\0')
    129 		goto enoent;
    130 
    131 	/* Prefix length can default to /32 only if all four octets spec'd. */
    132 	if (bits == -1) {
    133 		if (dst - odst == 4)
    134 			bits = ipv6 ? 128 : 32;
    135 		else
    136 			goto enoent;
    137 	}
    138 
    139 	/* If nothing was written to the destination, we found no address. */
    140 	if (dst == odst)
    141 		goto enoent;
    142 
    143 	/* If prefix length overspecifies mantissa, life is bad. */
    144 	if (((bits - (ipv6 ? 96 : 0)) / 8) > (dst - odst))
    145 		goto enoent;
    146 
    147 	/* Extend address to four octets. */
    148 	while (size-- > 0U)
    149 		*dst++ = 0;
    150 
    151 	*pbits = bits;
    152 	return (0);
    153 
    154  enoent:
    155 	errno = ENOENT;
    156 	return (-1);
    157 
    158  emsgsize:
    159 	errno = EMSGSIZE;
    160 	return (-1);
    161 }
    162 
    163 static int
    164 inet_cidr_pton_ipv6(const char *src, u_char *dst, int *pbits) {
    165 	static const char xdigits_l[] = "0123456789abcdef",
    166 			  xdigits_u[] = "0123456789ABCDEF";
    167 	u_char tmp[NS_IN6ADDRSZ], *tp, *endp, *colonp;
    168 	const char *xdigits, *curtok;
    169 	int ch, saw_xdigit;
    170 	u_int val;
    171 	int bits;
    172 
    173 	memset((tp = tmp), '\0', NS_IN6ADDRSZ);
    174 	endp = tp + NS_IN6ADDRSZ;
    175 	colonp = NULL;
    176 	/* Leading :: requires some special handling. */
    177 	if (*src == ':')
    178 		if (*++src != ':')
    179 			return (0);
    180 	curtok = src;
    181 	saw_xdigit = 0;
    182 	val = 0;
    183 	bits = -1;
    184 	while ((ch = *src++) != '\0') {
    185 		const char *pch;
    186 
    187 		if ((pch = strchr((xdigits = xdigits_l), ch)) == NULL)
    188 			pch = strchr((xdigits = xdigits_u), ch);
    189 		if (pch != NULL) {
    190 			val <<= 4;
    191 			val |= (pch - xdigits);
    192 			if (val > 0xffff)
    193 				return (0);
    194 			saw_xdigit = 1;
    195 			continue;
    196 		}
    197 		if (ch == ':') {
    198 			curtok = src;
    199 			if (!saw_xdigit) {
    200 				if (colonp)
    201 					return (0);
    202 				colonp = tp;
    203 				continue;
    204 			} else if (*src == '\0') {
    205 				return (0);
    206 			}
    207 			if (tp + NS_INT16SZ > endp)
    208 				return (0);
    209 			*tp++ = (u_char) (val >> 8) & 0xff;
    210 			*tp++ = (u_char) val & 0xff;
    211 			saw_xdigit = 0;
    212 			val = 0;
    213 			continue;
    214 		}
    215 		if (ch == '.' && ((tp + NS_INADDRSZ) <= endp) &&
    216 		    inet_cidr_pton_ipv4(curtok, tp, &bits, 1) == 0) {
    217 			tp += NS_INADDRSZ;
    218 			saw_xdigit = 0;
    219 			break;	/* '\0' was seen by inet_pton4(). */
    220 		}
    221 		if (ch == '/') {
    222 			bits = getbits(src, 1);
    223 			if (bits == -2)
    224 				goto enoent;
    225 			break;
    226 		}
    227 		goto enoent;
    228 	}
    229 	if (saw_xdigit) {
    230 		if (tp + NS_INT16SZ > endp)
    231 			goto emsgsize;
    232 		*tp++ = (u_char) (val >> 8) & 0xff;
    233 		*tp++ = (u_char) val & 0xff;
    234 	}
    235 	if (colonp != NULL) {
    236 		/*
    237 		 * Since some memmove()'s erroneously fail to handle
    238 		 * overlapping regions, we'll do the shift by hand.
    239 		 */
    240 		const int n = tp - colonp;
    241 		int i;
    242 
    243 		if (tp == endp)
    244 			goto enoent;
    245 		for (i = 1; i <= n; i++) {
    246 			endp[- i] = colonp[n - i];
    247 			colonp[n - i] = 0;
    248 		}
    249 		tp = endp;
    250 	}
    251 
    252 	memcpy(dst, tmp, NS_IN6ADDRSZ);
    253 
    254 	*pbits = bits;
    255 	return (0);
    256 
    257  enoent:
    258 	errno = ENOENT;
    259 	return (-1);
    260 
    261  emsgsize:
    262 	errno = EMSGSIZE;
    263 	return (-1);
    264 }
    265 
    266 static int
    267 getbits(const char *src, int ipv6) {
    268 	int bits = 0;
    269 	char *cp, ch;
    270 
    271 	if (*src == '\0')			/* syntax */
    272 		return (-2);
    273 	do {
    274 		ch = *src++;
    275 		cp = strchr(digits, ch);
    276 		if (cp == NULL)			/* syntax */
    277 			return (-2);
    278 		bits *= 10;
    279 		bits += cp - digits;
    280 		if (bits == 0 && *src != '\0')	/* no leading zeros */
    281 			return (-2);
    282 		if (bits > (ipv6 ? 128 : 32))	/* range error */
    283 			return (-2);
    284 	} while (*src != '\0');
    285 
    286 	return (bits);
    287 }
    288