1 /*-
2 * SPDX-License-Identifier: ISC
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 "port_before.h"
21
22 #include <sys/types.h>
23 #include <sys/socket.h>
24 #include <netinet/in.h>
25 #include <arpa/nameser.h>
26 #include <arpa/inet.h>
27
28 #include <errno.h>
29 #include <stdio.h>
30 #include <string.h>
31 #include <stdlib.h>
32
33 #include "port_after.h"
34
35 #ifdef SPRINTF_CHAR
36 # define SPRINTF(x) strlen(sprintf/**/x)
37 #else
38 # define SPRINTF(x) ((size_t)sprintf x)
39 #endif
40
41 static char *
42 inet_cidr_ntop_ipv4(const u_char *src, int bits, char *dst, size_t size);
43 static char *
44 inet_cidr_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size);
45
46 /*%
47 * char *
48 * inet_cidr_ntop(af, src, bits, dst, size)
49 * convert network address from network to presentation format.
50 * "src"'s size is determined from its "af".
51 * return:
52 * pointer to dst, or NULL if an error occurred (check errno).
53 * note:
54 * 192.5.5.1/28 has a nonzero host part, which means it isn't a network
55 * as called for by inet_net_ntop() but it can be a host address with
56 * an included netmask.
57 * author:
58 * Paul Vixie (ISC), October 1998
59 */
60 char *
inet_cidr_ntop(int af,const void * src,int bits,char * dst,size_t size)61 inet_cidr_ntop(int af, const void *src, int bits, char *dst, size_t size) {
62 switch (af) {
63 case AF_INET:
64 return (inet_cidr_ntop_ipv4(src, bits, dst, size));
65 case AF_INET6:
66 return (inet_cidr_ntop_ipv6(src, bits, dst, size));
67 default:
68 errno = EAFNOSUPPORT;
69 return (NULL);
70 }
71 }
72
73 static int
decoct(const u_char * src,int bytes,char * dst,size_t size)74 decoct(const u_char *src, int bytes, char *dst, size_t size) {
75 char *odst = dst;
76 char *t;
77 int b;
78
79 for (b = 1; b <= bytes; b++) {
80 if (size < sizeof "255.")
81 return (0);
82 t = dst;
83 dst += SPRINTF((dst, "%u", *src++));
84 if (b != bytes) {
85 *dst++ = '.';
86 *dst = '\0';
87 }
88 size -= (size_t)(dst - t);
89 }
90 return (dst - odst);
91 }
92
93 /*%
94 * static char *
95 * inet_cidr_ntop_ipv4(src, bits, dst, size)
96 * convert IPv4 network address from network to presentation format.
97 * "src"'s size is determined from its "af".
98 * return:
99 * pointer to dst, or NULL if an error occurred (check errno).
100 * note:
101 * network byte order assumed. this means 192.5.5.240/28 has
102 * 0b11110000 in its fourth octet.
103 * author:
104 * Paul Vixie (ISC), October 1998
105 */
106 static char *
inet_cidr_ntop_ipv4(const u_char * src,int bits,char * dst,size_t size)107 inet_cidr_ntop_ipv4(const u_char *src, int bits, char *dst, size_t size) {
108 char *odst = dst;
109 size_t len = 4;
110 size_t b;
111 size_t bytes;
112
113 if ((bits < -1) || (bits > 32)) {
114 errno = EINVAL;
115 return (NULL);
116 }
117
118 /* Find number of significant bytes in address. */
119 if (bits == -1)
120 len = 4;
121 else
122 for (len = 1, b = 1 ; b < 4U; b++)
123 if (*(src + b))
124 len = b + 1;
125
126 /* Format whole octets plus nonzero trailing octets. */
127 bytes = (((bits <= 0) ? 1 : bits) + 7) / 8;
128 if (len > bytes)
129 bytes = len;
130 b = decoct(src, bytes, dst, size);
131 if (b == 0U)
132 goto emsgsize;
133 dst += b;
134 size -= b;
135
136 if (bits != -1) {
137 /* Format CIDR /width. */
138 if (size < sizeof "/32")
139 goto emsgsize;
140 dst += SPRINTF((dst, "/%u", bits));
141 }
142
143 return (odst);
144
145 emsgsize:
146 errno = EMSGSIZE;
147 return (NULL);
148 }
149
150 static char *
inet_cidr_ntop_ipv6(const u_char * src,int bits,char * dst,size_t size)151 inet_cidr_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size) {
152 /*
153 * Note that int32_t and int16_t need only be "at least" large enough
154 * to contain a value of the specified size. On some systems, like
155 * Crays, there is no such thing as an integer variable with 16 bits.
156 * Keep this in mind if you think this function should have been coded
157 * to use pointer overlays. All the world's not a VAX.
158 */
159 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255/128"];
160 char *tp;
161 struct { int base, len; } best, cur;
162 u_int words[NS_IN6ADDRSZ / NS_INT16SZ];
163 int i;
164
165 if ((bits < -1) || (bits > 128)) {
166 errno = EINVAL;
167 return (NULL);
168 }
169
170 /*
171 * Preprocess:
172 * Copy the input (bytewise) array into a wordwise array.
173 * Find the longest run of 0x00's in src[] for :: shorthanding.
174 */
175 memset(words, '\0', sizeof words);
176 for (i = 0; i < NS_IN6ADDRSZ; i++)
177 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
178 best.base = -1;
179 best.len = 0;
180 cur.base = -1;
181 cur.len = 0;
182 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
183 if (words[i] == 0) {
184 if (cur.base == -1)
185 cur.base = i, cur.len = 1;
186 else
187 cur.len++;
188 } else {
189 if (cur.base != -1) {
190 if (best.base == -1 || cur.len > best.len)
191 best = cur;
192 cur.base = -1;
193 }
194 }
195 }
196 if (cur.base != -1) {
197 if (best.base == -1 || cur.len > best.len)
198 best = cur;
199 }
200 if (best.base != -1 && best.len < 2)
201 best.base = -1;
202
203 /*
204 * Format the result.
205 */
206 tp = tmp;
207 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
208 /* Are we inside the best run of 0x00's? */
209 if (best.base != -1 && i >= best.base &&
210 i < (best.base + best.len)) {
211 if (i == best.base)
212 *tp++ = ':';
213 continue;
214 }
215 /* Are we following an initial run of 0x00s or any real hex? */
216 if (i != 0)
217 *tp++ = ':';
218 /* Is this address an encapsulated IPv4? */
219 if (i == 6 && best.base == 0 && (best.len == 6 ||
220 (best.len == 7 && words[7] != 0x0001) ||
221 (best.len == 5 && words[5] == 0xffff))) {
222 int n;
223
224 if (src[15] || bits == -1 || bits > 120)
225 n = 4;
226 else if (src[14] || bits > 112)
227 n = 3;
228 else
229 n = 2;
230 n = decoct(src+12, n, tp, sizeof tmp - (tp - tmp));
231 if (n == 0) {
232 errno = EMSGSIZE;
233 return (NULL);
234 }
235 tp += strlen(tp);
236 break;
237 }
238 tp += SPRINTF((tp, "%x", words[i]));
239 }
240
241 /* Was it a trailing run of 0x00's? */
242 if (best.base != -1 && (best.base + best.len) ==
243 (NS_IN6ADDRSZ / NS_INT16SZ))
244 *tp++ = ':';
245 *tp = '\0';
246
247 if (bits != -1)
248 tp += SPRINTF((tp, "/%u", bits));
249
250 /*
251 * Check for overflow, copy, and we're done.
252 */
253 if ((size_t)(tp - tmp) > size) {
254 errno = EMSGSIZE;
255 return (NULL);
256 }
257 strcpy(dst, tmp);
258 return (dst);
259 }
260
261 /*! \file */
262