xref: /illumos-gate/usr/src/lib/libresolv2/common/inet/inet_net_pton.c (revision aedf2b3bb56b025fcaf87b49ec6c8aeea07f16d7)
1 /*
2  * Copyright (C) 2004, 2005, 2008  Internet Systems Consortium, Inc. ("ISC")
3  * Copyright (C) 1996, 1998, 1999, 2001, 2003  Internet Software Consortium.
4  *
5  * Permission to use, copy, modify, and/or distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
10  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
11  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
12  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
13  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
14  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
15  * PERFORMANCE OF THIS SOFTWARE.
16  */
17 
18 #if defined(LIBC_SCCS) && !defined(lint)
19 static const char rcsid[] = "$Id: inet_net_pton.c,v 1.10 2008/11/14 02:36:51 marka Exp $";
20 #endif
21 
22 #include "port_before.h"
23 
24 #include <sys/types.h>
25 #include <sys/socket.h>
26 #include <netinet/in.h>
27 #include <arpa/nameser.h>
28 #include <arpa/inet.h>
29 
30 #include <isc/assertions.h>
31 #include <ctype.h>
32 #include <errno.h>
33 #include <stdio.h>
34 #include <string.h>
35 #include <stdlib.h>
36 
37 #include "port_after.h"
38 
39 #ifdef SPRINTF_CHAR
40 # define SPRINTF(x) strlen(sprintf/**/x)
41 #else
42 # define SPRINTF(x) ((size_t)sprintf x)
43 #endif
44 
45 /*%
46  * static int
47  * inet_net_pton_ipv4(src, dst, size)
48  *	convert IPv4 network number from presentation to network format.
49  *	accepts hex octets, hex strings, decimal octets, and /CIDR.
50  *	"size" is in bytes and describes "dst".
51  * return:
52  *	number of bits, either imputed classfully or specified with /CIDR,
53  *	or -1 if some failure occurred (check errno).  ENOENT means it was
54  *	not an IPv4 network specification.
55  * note:
56  *	network byte order assumed.  this means 192.5.5.240/28 has
57  *	0b11110000 in its fourth octet.
58  * author:
59  *	Paul Vixie (ISC), June 1996
60  */
61 static int
62 inet_net_pton_ipv4(const char *src, u_char *dst, size_t size) {
63 	static const char xdigits[] = "0123456789abcdef";
64 	static const char digits[] = "0123456789";
65 	int n, ch, tmp = 0, dirty, bits;
66 	const u_char *odst = dst;
67 
68 	ch = *src++;
69 	if (ch == '0' && (src[0] == 'x' || src[0] == 'X')
70 	    && isascii((unsigned char)(src[1]))
71 	    && isxdigit((unsigned char)(src[1]))) {
72 		/* Hexadecimal: Eat nybble string. */
73 		if (size <= 0U)
74 			goto emsgsize;
75 		dirty = 0;
76 		src++;	/*%< skip x or X. */
77 		while ((ch = *src++) != '\0' && isascii(ch) && isxdigit(ch)) {
78 			if (isupper(ch))
79 				ch = tolower(ch);
80 			n = strchr(xdigits, ch) - xdigits;
81 			INSIST(n >= 0 && n <= 15);
82 			if (dirty == 0)
83 				tmp = n;
84 			else
85 				tmp = (tmp << 4) | n;
86 			if (++dirty == 2) {
87 				if (size-- <= 0U)
88 					goto emsgsize;
89 				*dst++ = (u_char) tmp;
90 				dirty = 0;
91 			}
92 		}
93 		if (dirty) {  /*%< Odd trailing nybble? */
94 			if (size-- <= 0U)
95 				goto emsgsize;
96 			*dst++ = (u_char) (tmp << 4);
97 		}
98 	} else if (isascii(ch) && isdigit(ch)) {
99 		/* Decimal: eat dotted digit string. */
100 		for (;;) {
101 			tmp = 0;
102 			do {
103 				n = strchr(digits, ch) - digits;
104 				INSIST(n >= 0 && n <= 9);
105 				tmp *= 10;
106 				tmp += n;
107 				if (tmp > 255)
108 					goto enoent;
109 			} while ((ch = *src++) != '\0' &&
110 				 isascii(ch) && isdigit(ch));
111 			if (size-- <= 0U)
112 				goto emsgsize;
113 			*dst++ = (u_char) tmp;
114 			if (ch == '\0' || ch == '/')
115 				break;
116 			if (ch != '.')
117 				goto enoent;
118 			ch = *src++;
119 			if (!isascii(ch) || !isdigit(ch))
120 				goto enoent;
121 		}
122 	} else
123 		goto enoent;
124 
125 	bits = -1;
126 	if (ch == '/' && isascii((unsigned char)(src[0])) &&
127 	    isdigit((unsigned char)(src[0])) && dst > odst) {
128 		/* CIDR width specifier.  Nothing can follow it. */
129 		ch = *src++;	/*%< Skip over the /. */
130 		bits = 0;
131 		do {
132 			n = strchr(digits, ch) - digits;
133 			INSIST(n >= 0 && n <= 9);
134 			bits *= 10;
135 			bits += n;
136 			if (bits > 32)
137 				goto enoent;
138 		} while ((ch = *src++) != '\0' && isascii(ch) && isdigit(ch));
139 		if (ch != '\0')
140 			goto enoent;
141 	}
142 
143 	/* Firey death and destruction unless we prefetched EOS. */
144 	if (ch != '\0')
145 		goto enoent;
146 
147 	/* If nothing was written to the destination, we found no address. */
148 	if (dst == odst)
149 		goto enoent;
150 	/* If no CIDR spec was given, infer width from net class. */
151 	if (bits == -1) {
152 		if (*odst >= 240)	/*%< Class E */
153 			bits = 32;
154 		else if (*odst >= 224)	/*%< Class D */
155 			bits = 8;
156 		else if (*odst >= 192)	/*%< Class C */
157 			bits = 24;
158 		else if (*odst >= 128)	/*%< Class B */
159 			bits = 16;
160 		else			/*%< Class A */
161 			bits = 8;
162 		/* If imputed mask is narrower than specified octets, widen. */
163 		if (bits < ((dst - odst) * 8))
164 			bits = (dst - odst) * 8;
165 		/*
166 		 * If there are no additional bits specified for a class D
167 		 * address adjust bits to 4.
168 		 */
169 		if (bits == 8 && *odst == 224)
170 			bits = 4;
171 	}
172 	/* Extend network to cover the actual mask. */
173 	while (bits > ((dst - odst) * 8)) {
174 		if (size-- <= 0U)
175 			goto emsgsize;
176 		*dst++ = '\0';
177 	}
178 	return (bits);
179 
180  enoent:
181 	errno = ENOENT;
182 	return (-1);
183 
184  emsgsize:
185 	errno = EMSGSIZE;
186 	return (-1);
187 }
188 
189 static int
190 getbits(const char *src, int *bitsp) {
191 	static const char digits[] = "0123456789";
192 	int n;
193 	int val;
194 	char ch;
195 
196 	val = 0;
197 	n = 0;
198 	while ((ch = *src++) != '\0') {
199 		const char *pch;
200 
201 		pch = strchr(digits, ch);
202 		if (pch != NULL) {
203 			if (n++ != 0 && val == 0)	/*%< no leading zeros */
204 				return (0);
205 			val *= 10;
206 			val += (pch - digits);
207 			if (val > 128)			/*%< range */
208 				return (0);
209 			continue;
210 		}
211 		return (0);
212 	}
213 	if (n == 0)
214 		return (0);
215 	*bitsp = val;
216 	return (1);
217 }
218 
219 static int
220 getv4(const char *src, u_char *dst, int *bitsp) {
221 	static const char digits[] = "0123456789";
222 	u_char *odst = dst;
223 	int n;
224 	u_int val;
225 	char ch;
226 
227 	val = 0;
228 	n = 0;
229 	while ((ch = *src++) != '\0') {
230 		const char *pch;
231 
232 		pch = strchr(digits, ch);
233 		if (pch != NULL) {
234 			if (n++ != 0 && val == 0)	/*%< no leading zeros */
235 				return (0);
236 			val *= 10;
237 			val += (pch - digits);
238 			if (val > 255)			/*%< range */
239 				return (0);
240 			continue;
241 		}
242 		if (ch == '.' || ch == '/') {
243 			if (dst - odst > 3)		/*%< too many octets? */
244 				return (0);
245 			*dst++ = val;
246 			if (ch == '/')
247 				return (getbits(src, bitsp));
248 			val = 0;
249 			n = 0;
250 			continue;
251 		}
252 		return (0);
253 	}
254 	if (n == 0)
255 		return (0);
256 	if (dst - odst > 3)		/*%< too many octets? */
257 		return (0);
258 	*dst++ = val;
259 	return (1);
260 }
261 
262 static int
263 inet_net_pton_ipv6(const char *src, u_char *dst, size_t size) {
264 	static const char xdigits_l[] = "0123456789abcdef",
265 			  xdigits_u[] = "0123456789ABCDEF";
266 	u_char tmp[NS_IN6ADDRSZ], *tp, *endp, *colonp;
267 	const char *xdigits, *curtok;
268 	int ch, saw_xdigit;
269 	u_int val;
270 	int digits;
271 	int bits;
272 	size_t bytes;
273 	int words;
274 	int ipv4;
275 
276 	memset((tp = tmp), '\0', NS_IN6ADDRSZ);
277 	endp = tp + NS_IN6ADDRSZ;
278 	colonp = NULL;
279 	/* Leading :: requires some special handling. */
280 	if (*src == ':')
281 		if (*++src != ':')
282 			goto enoent;
283 	curtok = src;
284 	saw_xdigit = 0;
285 	val = 0;
286 	digits = 0;
287 	bits = -1;
288 	ipv4 = 0;
289 	while ((ch = *src++) != '\0') {
290 		const char *pch;
291 
292 		if ((pch = strchr((xdigits = xdigits_l), ch)) == NULL)
293 			pch = strchr((xdigits = xdigits_u), ch);
294 		if (pch != NULL) {
295 			val <<= 4;
296 			val |= (pch - xdigits);
297 			if (++digits > 4)
298 				goto enoent;
299 			saw_xdigit = 1;
300 			continue;
301 		}
302 		if (ch == ':') {
303 			curtok = src;
304 			if (!saw_xdigit) {
305 				if (colonp)
306 					goto enoent;
307 				colonp = tp;
308 				continue;
309 			} else if (*src == '\0')
310 				goto enoent;
311 			if (tp + NS_INT16SZ > endp)
312 				return (0);
313 			*tp++ = (u_char) (val >> 8) & 0xff;
314 			*tp++ = (u_char) val & 0xff;
315 			saw_xdigit = 0;
316 			digits = 0;
317 			val = 0;
318 			continue;
319 		}
320 		if (ch == '.' && ((tp + NS_INADDRSZ) <= endp) &&
321 		     getv4(curtok, tp, &bits) > 0) {
322 			tp += NS_INADDRSZ;
323 			saw_xdigit = 0;
324 			ipv4 = 1;
325 			break;	/*%< '\\0' was seen by inet_pton4(). */
326 		}
327 		if (ch == '/' && getbits(src, &bits) > 0)
328 			break;
329 		goto enoent;
330 	}
331 	if (saw_xdigit) {
332 		if (tp + NS_INT16SZ > endp)
333 			goto enoent;
334 		*tp++ = (u_char) (val >> 8) & 0xff;
335 		*tp++ = (u_char) val & 0xff;
336 	}
337 	if (bits == -1)
338 		bits = 128;
339 
340 	words = (bits + 15) / 16;
341 	if (words < 2)
342 		words = 2;
343 	if (ipv4)
344 		words = 8;
345 	endp =  tmp + 2 * words;
346 
347 	if (colonp != NULL) {
348 		/*
349 		 * Since some memmove()'s erroneously fail to handle
350 		 * overlapping regions, we'll do the shift by hand.
351 		 */
352 		const int n = tp - colonp;
353 		int i;
354 
355 		if (tp == endp)
356 			goto enoent;
357 		for (i = 1; i <= n; i++) {
358 			endp[- i] = colonp[n - i];
359 			colonp[n - i] = 0;
360 		}
361 		tp = endp;
362 	}
363 	if (tp != endp)
364 		goto enoent;
365 
366 	bytes = (bits + 7) / 8;
367 	if (bytes > size)
368 		goto emsgsize;
369 	memcpy(dst, tmp, bytes);
370 	return (bits);
371 
372  enoent:
373 	errno = ENOENT;
374 	return (-1);
375 
376  emsgsize:
377 	errno = EMSGSIZE;
378 	return (-1);
379 }
380 
381 /*%
382  * int
383  * inet_net_pton(af, src, dst, size)
384  *	convert network number from presentation to network format.
385  *	accepts hex octets, hex strings, decimal octets, and /CIDR.
386  *	"size" is in bytes and describes "dst".
387  * return:
388  *	number of bits, either imputed classfully or specified with /CIDR,
389  *	or -1 if some failure occurred (check errno).  ENOENT means it was
390  *	not a valid network specification.
391  * author:
392  *	Paul Vixie (ISC), June 1996
393  */
394 int
395 inet_net_pton(int af, const char *src, void *dst, size_t size) {
396 	switch (af) {
397 	case AF_INET:
398 		return (inet_net_pton_ipv4(src, dst, size));
399 	case AF_INET6:
400 		return (inet_net_pton_ipv6(src, dst, size));
401 	default:
402 		errno = EAFNOSUPPORT;
403 		return (-1);
404 	}
405 }
406 
407 /*! \file */
408