xref: /freebsd/lib/libc/inet/inet_net_pton.c (revision 580744621f33383027108364dcadad718df46ffe)
1 /*-
2  * SPDX-License-Identifier: ISC
3  *
4  * Copyright (C) 2004, 2005, 2008  Internet Systems Consortium, Inc. ("ISC")
5  * Copyright (C) 1996, 1998, 1999, 2001, 2003  Internet Software Consortium.
6  *
7  * Permission to use, copy, modify, and/or 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 WITH
12  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
13  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
14  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
15  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
16  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
17  * PERFORMANCE OF THIS SOFTWARE.
18  */
19 
20 #if defined(LIBC_SCCS) && !defined(lint)
21 static const char rcsid[] = "$Id: inet_net_pton.c,v 1.10 2008/11/14 02:36:51 marka Exp $";
22 #endif
23 #include <sys/cdefs.h>
24 __FBSDID("$FreeBSD$");
25 
26 #include "port_before.h"
27 
28 #include <sys/types.h>
29 #include <sys/socket.h>
30 #include <netinet/in.h>
31 #include <arpa/nameser.h>
32 #include <arpa/inet.h>
33 
34 #include <assert.h>
35 #include <ctype.h>
36 #include <errno.h>
37 #include <stdio.h>
38 #include <string.h>
39 #include <stdlib.h>
40 
41 #include "port_after.h"
42 
43 #ifdef SPRINTF_CHAR
44 # define SPRINTF(x) strlen(sprintf/**/x)
45 #else
46 # define SPRINTF(x) ((size_t)sprintf x)
47 #endif
48 
49 /*%
50  * static int
51  * inet_net_pton_ipv4(src, dst, size)
52  *	convert IPv4 network number from presentation to network format.
53  *	accepts hex octets, hex strings, decimal octets, and /CIDR.
54  *	"size" is in bytes and describes "dst".
55  * return:
56  *	number of bits, either imputed classfully or specified with /CIDR,
57  *	or -1 if some failure occurred (check errno).  ENOENT means it was
58  *	not an IPv4 network specification.
59  * note:
60  *	network byte order assumed.  this means 192.5.5.240/28 has
61  *	0b11110000 in its fourth octet.
62  * author:
63  *	Paul Vixie (ISC), June 1996
64  */
65 static int
66 inet_net_pton_ipv4(const char *src, u_char *dst, size_t size) {
67 	static const char xdigits[] = "0123456789abcdef";
68 	static const char digits[] = "0123456789";
69 	int n, ch, tmp = 0, dirty, bits;
70 	const u_char *odst = dst;
71 
72 	ch = *src++;
73 	if (ch == '0' && (src[0] == 'x' || src[0] == 'X')
74 	    && isascii((unsigned char)(src[1]))
75 	    && isxdigit((unsigned char)(src[1]))) {
76 		/* Hexadecimal: Eat nybble string. */
77 		if (size <= 0U)
78 			goto emsgsize;
79 		dirty = 0;
80 		src++;	/*%< skip x or X. */
81 		while ((ch = *src++) != '\0' && isascii(ch) && isxdigit(ch)) {
82 			if (isupper(ch))
83 				ch = tolower(ch);
84 			n = strchr(xdigits, ch) - xdigits;
85 			assert(n >= 0 && n <= 15);
86 			if (dirty == 0)
87 				tmp = n;
88 			else
89 				tmp = (tmp << 4) | n;
90 			if (++dirty == 2) {
91 				if (size-- <= 0U)
92 					goto emsgsize;
93 				*dst++ = (u_char) tmp;
94 				dirty = 0;
95 			}
96 		}
97 		if (dirty) {  /*%< Odd trailing nybble? */
98 			if (size-- <= 0U)
99 				goto emsgsize;
100 			*dst++ = (u_char) (tmp << 4);
101 		}
102 	} else if (isascii(ch) && isdigit(ch)) {
103 		/* Decimal: eat dotted digit string. */
104 		for (;;) {
105 			tmp = 0;
106 			do {
107 				n = strchr(digits, ch) - digits;
108 				assert(n >= 0 && n <= 9);
109 				tmp *= 10;
110 				tmp += n;
111 				if (tmp > 255)
112 					goto enoent;
113 			} while ((ch = *src++) != '\0' &&
114 				 isascii(ch) && isdigit(ch));
115 			if (size-- <= 0U)
116 				goto emsgsize;
117 			*dst++ = (u_char) tmp;
118 			if (ch == '\0' || ch == '/')
119 				break;
120 			if (ch != '.')
121 				goto enoent;
122 			ch = *src++;
123 			if (!isascii(ch) || !isdigit(ch))
124 				goto enoent;
125 		}
126 	} else
127 		goto enoent;
128 
129 	bits = -1;
130 	if (ch == '/' && isascii((unsigned char)(src[0])) &&
131 	    isdigit((unsigned char)(src[0])) && dst > odst) {
132 		/* CIDR width specifier.  Nothing can follow it. */
133 		ch = *src++;	/*%< Skip over the /. */
134 		bits = 0;
135 		do {
136 			n = strchr(digits, ch) - digits;
137 			assert(n >= 0 && n <= 9);
138 			bits *= 10;
139 			bits += n;
140 			if (bits > 32)
141 				goto enoent;
142 		} while ((ch = *src++) != '\0' && isascii(ch) && isdigit(ch));
143 		if (ch != '\0')
144 			goto enoent;
145 	}
146 
147 	/* Firey death and destruction unless we prefetched EOS. */
148 	if (ch != '\0')
149 		goto enoent;
150 
151 	/* If nothing was written to the destination, we found no address. */
152 	if (dst == odst)
153 		goto enoent;
154 	/* If no CIDR spec was given, infer width from net class. */
155 	if (bits == -1) {
156 		if (*odst >= 240)	/*%< Class E */
157 			bits = 32;
158 		else if (*odst >= 224)	/*%< Class D */
159 			bits = 8;
160 		else if (*odst >= 192)	/*%< Class C */
161 			bits = 24;
162 		else if (*odst >= 128)	/*%< Class B */
163 			bits = 16;
164 		else			/*%< Class A */
165 			bits = 8;
166 		/* If imputed mask is narrower than specified octets, widen. */
167 		if (bits < ((dst - odst) * 8))
168 			bits = (dst - odst) * 8;
169 		/*
170 		 * If there are no additional bits specified for a class D
171 		 * address adjust bits to 4.
172 		 */
173 		if (bits == 8 && *odst == 224)
174 			bits = 4;
175 	}
176 	/* Extend network to cover the actual mask. */
177 	while (bits > ((dst - odst) * 8)) {
178 		if (size-- <= 0U)
179 			goto emsgsize;
180 		*dst++ = '\0';
181 	}
182 	return (bits);
183 
184  enoent:
185 	errno = ENOENT;
186 	return (-1);
187 
188  emsgsize:
189 	errno = EMSGSIZE;
190 	return (-1);
191 }
192 
193 static int
194 getbits(const char *src, int *bitsp) {
195 	static const char digits[] = "0123456789";
196 	int n;
197 	int val;
198 	char ch;
199 
200 	val = 0;
201 	n = 0;
202 	while ((ch = *src++) != '\0') {
203 		const char *pch;
204 
205 		pch = strchr(digits, ch);
206 		if (pch != NULL) {
207 			if (n++ != 0 && val == 0)	/*%< no leading zeros */
208 				return (0);
209 			val *= 10;
210 			val += (pch - digits);
211 			if (val > 128)			/*%< range */
212 				return (0);
213 			continue;
214 		}
215 		return (0);
216 	}
217 	if (n == 0)
218 		return (0);
219 	*bitsp = val;
220 	return (1);
221 }
222 
223 static int
224 getv4(const char *src, u_char *dst, int *bitsp) {
225 	static const char digits[] = "0123456789";
226 	u_char *odst = dst;
227 	int n;
228 	u_int val;
229 	char ch;
230 
231 	val = 0;
232 	n = 0;
233 	while ((ch = *src++) != '\0') {
234 		const char *pch;
235 
236 		pch = strchr(digits, ch);
237 		if (pch != NULL) {
238 			if (n++ != 0 && val == 0)	/*%< no leading zeros */
239 				return (0);
240 			val *= 10;
241 			val += (pch - digits);
242 			if (val > 255)			/*%< range */
243 				return (0);
244 			continue;
245 		}
246 		if (ch == '.' || ch == '/') {
247 			if (dst - odst > 3)		/*%< too many octets? */
248 				return (0);
249 			*dst++ = val;
250 			if (ch == '/')
251 				return (getbits(src, bitsp));
252 			val = 0;
253 			n = 0;
254 			continue;
255 		}
256 		return (0);
257 	}
258 	if (n == 0)
259 		return (0);
260 	if (dst - odst > 3)		/*%< too many octets? */
261 		return (0);
262 	*dst++ = val;
263 	return (1);
264 }
265 
266 static int
267 inet_net_pton_ipv6(const char *src, u_char *dst, size_t size) {
268 	static const char xdigits_l[] = "0123456789abcdef",
269 			  xdigits_u[] = "0123456789ABCDEF";
270 	u_char tmp[NS_IN6ADDRSZ], *tp, *endp, *colonp;
271 	const char *xdigits, *curtok;
272 	int ch, saw_xdigit;
273 	u_int val;
274 	int digits;
275 	int bits;
276 	size_t bytes;
277 	int words;
278 	int ipv4;
279 
280 	memset((tp = tmp), '\0', NS_IN6ADDRSZ);
281 	endp = tp + NS_IN6ADDRSZ;
282 	colonp = NULL;
283 	/* Leading :: requires some special handling. */
284 	if (*src == ':')
285 		if (*++src != ':')
286 			goto enoent;
287 	curtok = src;
288 	saw_xdigit = 0;
289 	val = 0;
290 	digits = 0;
291 	bits = -1;
292 	ipv4 = 0;
293 	while ((ch = *src++) != '\0') {
294 		const char *pch;
295 
296 		if ((pch = strchr((xdigits = xdigits_l), ch)) == NULL)
297 			pch = strchr((xdigits = xdigits_u), ch);
298 		if (pch != NULL) {
299 			val <<= 4;
300 			val |= (pch - xdigits);
301 			if (++digits > 4)
302 				goto enoent;
303 			saw_xdigit = 1;
304 			continue;
305 		}
306 		if (ch == ':') {
307 			curtok = src;
308 			if (!saw_xdigit) {
309 				if (colonp)
310 					goto enoent;
311 				colonp = tp;
312 				continue;
313 			} else if (*src == '\0')
314 				goto enoent;
315 			if (tp + NS_INT16SZ > endp)
316 				return (0);
317 			*tp++ = (u_char) (val >> 8) & 0xff;
318 			*tp++ = (u_char) val & 0xff;
319 			saw_xdigit = 0;
320 			digits = 0;
321 			val = 0;
322 			continue;
323 		}
324 		if (ch == '.' && ((tp + NS_INADDRSZ) <= endp) &&
325 		     getv4(curtok, tp, &bits) > 0) {
326 			tp += NS_INADDRSZ;
327 			saw_xdigit = 0;
328 			ipv4 = 1;
329 			break;	/*%< '\\0' was seen by inet_pton4(). */
330 		}
331 		if (ch == '/' && getbits(src, &bits) > 0)
332 			break;
333 		goto enoent;
334 	}
335 	if (saw_xdigit) {
336 		if (tp + NS_INT16SZ > endp)
337 			goto enoent;
338 		*tp++ = (u_char) (val >> 8) & 0xff;
339 		*tp++ = (u_char) val & 0xff;
340 	}
341 	if (bits == -1)
342 		bits = 128;
343 
344 	words = (bits + 15) / 16;
345 	if (words < 2)
346 		words = 2;
347 	if (ipv4)
348 		words = 8;
349 	endp =  tmp + 2 * words;
350 
351 	if (colonp != NULL) {
352 		/*
353 		 * Since some memmove()'s erroneously fail to handle
354 		 * overlapping regions, we'll do the shift by hand.
355 		 */
356 		const int n = tp - colonp;
357 		int i;
358 
359 		if (tp == endp)
360 			goto enoent;
361 		for (i = 1; i <= n; i++) {
362 			endp[- i] = colonp[n - i];
363 			colonp[n - i] = 0;
364 		}
365 		tp = endp;
366 	}
367 	if (tp != endp)
368 		goto enoent;
369 
370 	bytes = (bits + 7) / 8;
371 	if (bytes > size)
372 		goto emsgsize;
373 	memcpy(dst, tmp, bytes);
374 	return (bits);
375 
376  enoent:
377 	errno = ENOENT;
378 	return (-1);
379 
380  emsgsize:
381 	errno = EMSGSIZE;
382 	return (-1);
383 }
384 
385 /*%
386  * int
387  * inet_net_pton(af, src, dst, size)
388  *	convert network number from presentation to network format.
389  *	accepts hex octets, hex strings, decimal octets, and /CIDR.
390  *	"size" is in bytes and describes "dst".
391  * return:
392  *	number of bits, either imputed classfully or specified with /CIDR,
393  *	or -1 if some failure occurred (check errno).  ENOENT means it was
394  *	not a valid network specification.
395  * author:
396  *	Paul Vixie (ISC), June 1996
397  */
398 int
399 inet_net_pton(int af, const char *src, void *dst, size_t size) {
400 	switch (af) {
401 	case AF_INET:
402 		return (inet_net_pton_ipv4(src, dst, size));
403 	case AF_INET6:
404 		return (inet_net_pton_ipv6(src, dst, size));
405 	default:
406 		errno = EAFNOSUPPORT;
407 		return (-1);
408 	}
409 }
410 
411 /*
412  * Weak aliases for applications that use certain private entry points,
413  * and fail to include <arpa/inet.h>.
414  */
415 #undef inet_net_pton
416 __weak_reference(__inet_net_pton, inet_net_pton);
417 
418 /*! \file */
419