1 /* $NetBSD: inet_cidr_pton.c,v 1.10 2024/01/20 14:52:47 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 1.6 2005/04/27 04:56:19 sra Exp";
24 #else
25 __RCSID("$NetBSD: inet_cidr_pton.c,v 1.10 2024/01/20 14:52:47 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 <stddef.h>
44 #include <stdlib.h>
45
46 #include "port_after.h"
47
48 #ifdef __weak_alias
49 __weak_alias(inet_cidr_pton,_inet_cidr_pton)
50 #endif
51
52 static int inet_cidr_pton_ipv4(const char *src, u_char *dst,
53 int *bits, int ipv6);
54 static int inet_cidr_pton_ipv6(const char *src, u_char *dst, int *bits);
55
56 static int getbits(const char *, int ipv6);
57
58 /*%
59 * int
60 * inet_cidr_pton(af, src, dst, *bits)
61 * convert network address from presentation to network format.
62 * accepts inet_pton()'s input for this "af" plus trailing "/CIDR".
63 * "dst" is assumed large enough for its "af". "bits" is set to the
64 * /CIDR prefix length, which can have defaults (like /32 for IPv4).
65 * return:
66 * -1 if an error occurred (inspect errno; ENOENT means bad format).
67 * 0 if successful conversion occurred.
68 * note:
69 * 192.5.5.1/28 has a nonzero host part, which means it isn't a network
70 * as called for by inet_net_pton() but it can be a host address with
71 * an included netmask.
72 * author:
73 * Paul Vixie (ISC), October 1998
74 */
75 int
inet_cidr_pton(int af,const char * src,void * dst,int * bits)76 inet_cidr_pton(int af, const char *src, void *dst, int *bits) {
77 switch (af) {
78 case AF_INET:
79 return inet_cidr_pton_ipv4(src, dst, bits, 0);
80 case AF_INET6:
81 return inet_cidr_pton_ipv6(src, dst, bits);
82 default:
83 errno = EAFNOSUPPORT;
84 return -1;
85 }
86 }
87
88 static const char digits[] = "0123456789";
89
90 static int
inet_cidr_pton_ipv4(const char * src,u_char * dst,int * pbits,int ipv6)91 inet_cidr_pton_ipv4(const char *src, u_char *dst, int *pbits, int ipv6) {
92 const u_char *odst = dst;
93 int ch, bits;
94 ptrdiff_t n, tmp;
95 size_t size = 4;
96
97 /* Get the mantissa. */
98 while (ch = *src++, (isascii(ch) && isdigit(ch))) {
99 tmp = 0;
100 do {
101 n = strchr(digits, ch) - digits;
102 INSIST(n >= 0 && n <= 9);
103 tmp *= 10;
104 tmp += n;
105 if (tmp > 255)
106 goto enoent;
107 } while ((ch = *src++) != '\0' && isascii(ch) && isdigit(ch));
108 if (size-- == 0U)
109 goto emsgsize;
110 *dst++ = (u_char) tmp;
111 if (ch == '\0' || ch == '/')
112 break;
113 if (ch != '.')
114 goto enoent;
115 }
116
117 /* Get the prefix length if any. */
118 bits = -1;
119 if (ch == '/' && dst > odst) {
120 bits = getbits(src, ipv6);
121 if (bits == -2)
122 goto enoent;
123 } else if (ch != '\0')
124 goto enoent;
125
126 /* Prefix length can default to /32 only if all four octets spec'd. */
127 if (bits == -1) {
128 if (dst - odst == 4)
129 bits = ipv6 ? 128 : 32;
130 else
131 goto enoent;
132 }
133
134 /* If nothing was written to the destination, we found no address. */
135 if (dst == odst)
136 goto enoent;
137
138 /* If prefix length overspecifies mantissa, life is bad. */
139 if (((bits - (ipv6 ? 96 : 0)) / 8) > (dst - odst))
140 goto enoent;
141
142 /* Extend address to four octets. */
143 while (size-- > 0U)
144 *dst++ = 0;
145
146 *pbits = bits;
147 return 0;
148
149 enoent:
150 errno = ENOENT;
151 return -1;
152
153 emsgsize:
154 errno = EMSGSIZE;
155 return -1;
156 }
157
158 static int
inet_cidr_pton_ipv6(const char * src,u_char * dst,int * pbits)159 inet_cidr_pton_ipv6(const char *src, u_char *dst, int *pbits) {
160 static const char xdigits_l[] = "0123456789abcdef",
161 xdigits_u[] = "0123456789ABCDEF";
162 u_char tmp[NS_IN6ADDRSZ], *tp, *endp, *colonp;
163 const char *xdigits, *curtok;
164 int ch, saw_xdigit;
165 u_int val;
166 int bits;
167
168 memset((tp = tmp), '\0', NS_IN6ADDRSZ);
169 endp = tp + NS_IN6ADDRSZ;
170 colonp = NULL;
171 /* Leading :: requires some special handling. */
172 if (*src == ':')
173 if (*++src != ':')
174 return 0;
175 curtok = src;
176 saw_xdigit = 0;
177 val = 0;
178 bits = -1;
179 while ((ch = *src++) != '\0') {
180 const char *pch;
181
182 if ((pch = strchr((xdigits = xdigits_l), ch)) == NULL)
183 pch = strchr((xdigits = xdigits_u), ch);
184 if (pch != NULL) {
185 val <<= 4;
186 val |= (int)(pch - xdigits);
187 if (val > 0xffff)
188 return 0;
189 saw_xdigit = 1;
190 continue;
191 }
192 if (ch == ':') {
193 curtok = src;
194 if (!saw_xdigit) {
195 if (colonp)
196 return 0;
197 colonp = tp;
198 continue;
199 } else if (*src == '\0') {
200 return 0;
201 }
202 if (tp + NS_INT16SZ > endp)
203 return 0;
204 *tp++ = (u_char) (val >> 8) & 0xff;
205 *tp++ = (u_char) val & 0xff;
206 saw_xdigit = 0;
207 val = 0;
208 continue;
209 }
210 if (ch == '.' && ((tp + NS_INADDRSZ) <= endp) &&
211 inet_cidr_pton_ipv4(curtok, tp, &bits, 1) == 0) {
212 tp += NS_INADDRSZ;
213 saw_xdigit = 0;
214 break; /*%< '\\0' was seen by inet_pton4(). */
215 }
216 if (ch == '/') {
217 bits = getbits(src, 1);
218 if (bits == -2)
219 goto enoent;
220 break;
221 }
222 goto enoent;
223 }
224 if (saw_xdigit) {
225 if (tp + NS_INT16SZ > endp)
226 goto emsgsize;
227 *tp++ = (u_char) (val >> 8) & 0xff;
228 *tp++ = (u_char) val & 0xff;
229 }
230 if (colonp != NULL) {
231 /*
232 * Since some memmove()'s erroneously fail to handle
233 * overlapping regions, we'll do the shift by hand.
234 */
235 const ptrdiff_t n = tp - colonp;
236 int i;
237
238 if (tp == endp)
239 goto enoent;
240 for (i = 1; i <= n; i++) {
241 endp[- i] = colonp[n - i];
242 colonp[n - i] = 0;
243 }
244 tp = endp;
245 }
246
247 memcpy(dst, tmp, NS_IN6ADDRSZ);
248
249 *pbits = bits;
250 return 0;
251
252 enoent:
253 errno = ENOENT;
254 return -1;
255
256 emsgsize:
257 errno = EMSGSIZE;
258 return -1;
259 }
260
261 static int
getbits(const char * src,int ipv6)262 getbits(const char *src, int ipv6) {
263 int bits = 0;
264
265 if (*src == '\0') /*%< syntax */
266 return -2;
267 do {
268 char ch = *src++;
269 const char *cp = strchr(digits, ch);
270 if (cp == NULL) /*%< syntax */
271 return -2;
272 bits *= 10;
273 bits += (int)(cp - digits);
274 if (bits == 0 && *src != '\0') /*%< no leading zeros */
275 return -2;
276 if (bits > (ipv6 ? 128 : 32)) /*%< range error */
277 return -2;
278 } while (*src != '\0');
279
280 return bits;
281 }
282
283 /*! \file */
284