1 /*
2 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (c) 1998,1999 by Internet Software Consortium.
4 *
5 * Permission to use, copy, modify, and 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
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
15 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 *
17 * $Id: inet_cidr_ntop.c,v 1.7 2006/10/11 02:18:18 marka Exp $
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 static char *
36 inet_cidr_ntop_ipv4(const u_char *src, int bits, char *dst, size_t size);
37 static char *
38 inet_cidr_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size);
39
40 /*%
41 * char *
42 * inet_cidr_ntop(af, src, bits, dst, size)
43 * convert network address from network to presentation format.
44 * "src"'s size is determined from its "af".
45 * return:
46 * pointer to dst, or NULL if an error occurred (check errno).
47 * note:
48 * 192.5.5.1/28 has a nonzero host part, which means it isn't a network
49 * as called for by inet_net_ntop() but it can be a host address with
50 * an included netmask.
51 * author:
52 * Paul Vixie (ISC), October 1998
53 */
54 char *
inet_cidr_ntop(int af,const void * src,int bits,char * dst,size_t size)55 inet_cidr_ntop(int af, const void *src, int bits, char *dst, size_t size) {
56 switch (af) {
57 case AF_INET:
58 return (inet_cidr_ntop_ipv4(src, bits, dst, size));
59 case AF_INET6:
60 return (inet_cidr_ntop_ipv6(src, bits, dst, size));
61 default:
62 errno = EAFNOSUPPORT;
63 return (NULL);
64 }
65 }
66
67 static int
decoct(const u_char * src,int bytes,char * dst,size_t size)68 decoct(const u_char *src, int bytes, char *dst, size_t size) {
69 char *odst = dst;
70 char *t;
71 int b;
72
73 for (b = 1; b <= bytes; b++) {
74 if (size < sizeof "255.")
75 return (0);
76 t = dst;
77 dst += sprintf(dst, "%u", *src++);
78 if (b != bytes) {
79 *dst++ = '.';
80 *dst = '\0';
81 }
82 size -= (size_t)(dst - t);
83 }
84 return (dst - odst);
85 }
86
87 /*%
88 * static char *
89 * inet_cidr_ntop_ipv4(src, bits, dst, size)
90 * convert IPv4 network address from network to presentation format.
91 * "src"'s size is determined from its "af".
92 * return:
93 * pointer to dst, or NULL if an error occurred (check errno).
94 * note:
95 * network byte order assumed. this means 192.5.5.240/28 has
96 * 0b11110000 in its fourth octet.
97 * author:
98 * Paul Vixie (ISC), October 1998
99 */
100 static char *
inet_cidr_ntop_ipv4(const u_char * src,int bits,char * dst,size_t size)101 inet_cidr_ntop_ipv4(const u_char *src, int bits, char *dst, size_t size) {
102 char *odst = dst;
103 size_t len = 4;
104 size_t b;
105 size_t bytes;
106
107 if ((bits < -1) || (bits > 32)) {
108 errno = EINVAL;
109 return (NULL);
110 }
111
112 /* Find number of significant bytes in address. */
113 if (bits == -1)
114 len = 4;
115 else
116 for (len = 1, b = 1 ; b < 4U; b++)
117 if (*(src + b))
118 len = b + 1;
119
120 /* Format whole octets plus nonzero trailing octets. */
121 bytes = (((bits <= 0) ? 1 : bits) + 7) / 8;
122 if (len > bytes)
123 bytes = len;
124 b = decoct(src, bytes, dst, size);
125 if (b == 0U)
126 goto emsgsize;
127 dst += b;
128 size -= b;
129
130 if (bits != -1) {
131 /* Format CIDR /width. */
132 if (size < sizeof "/32")
133 goto emsgsize;
134 dst += sprintf(dst, "/%u", bits);
135 }
136
137 return (odst);
138
139 emsgsize:
140 errno = EMSGSIZE;
141 return (NULL);
142 }
143
144 static char *
inet_cidr_ntop_ipv6(const u_char * src,int bits,char * dst,size_t size)145 inet_cidr_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size) {
146 /*
147 * Note that int32_t and int16_t need only be "at least" large enough
148 * to contain a value of the specified size. On some systems, like
149 * Crays, there is no such thing as an integer variable with 16 bits.
150 * Keep this in mind if you think this function should have been coded
151 * to use pointer overlays. All the world's not a VAX.
152 */
153 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255/128"];
154 char *tp;
155 struct { int base, len; } best, cur;
156 u_int words[NS_IN6ADDRSZ / NS_INT16SZ];
157 int i;
158
159 if ((bits < -1) || (bits > 128)) {
160 errno = EINVAL;
161 return (NULL);
162 }
163
164 /*
165 * Preprocess:
166 * Copy the input (bytewise) array into a wordwise array.
167 * Find the longest run of 0x00's in src[] for :: shorthanding.
168 */
169 memset(words, '\0', sizeof words);
170 for (i = 0; i < NS_IN6ADDRSZ; i++)
171 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
172 best.base = -1;
173 best.len = 0;
174 cur.base = -1;
175 cur.len = 0;
176 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
177 if (words[i] == 0) {
178 if (cur.base == -1)
179 cur.base = i, cur.len = 1;
180 else
181 cur.len++;
182 } else {
183 if (cur.base != -1) {
184 if (best.base == -1 || cur.len > best.len)
185 best = cur;
186 cur.base = -1;
187 }
188 }
189 }
190 if (cur.base != -1) {
191 if (best.base == -1 || cur.len > best.len)
192 best = cur;
193 }
194 if (best.base != -1 && best.len < 2)
195 best.base = -1;
196
197 /*
198 * Format the result.
199 */
200 tp = tmp;
201 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
202 /* Are we inside the best run of 0x00's? */
203 if (best.base != -1 && i >= best.base &&
204 i < (best.base + best.len)) {
205 if (i == best.base)
206 *tp++ = ':';
207 continue;
208 }
209 /* Are we following an initial run of 0x00s or any real hex? */
210 if (i != 0)
211 *tp++ = ':';
212 /* Is this address an encapsulated IPv4? */
213 if (i == 6 && best.base == 0 && (best.len == 6 ||
214 (best.len == 7 && words[7] != 0x0001) ||
215 (best.len == 5 && words[5] == 0xffff))) {
216 int n;
217
218 if (src[15] || bits == -1 || bits > 120)
219 n = 4;
220 else if (src[14] || bits > 112)
221 n = 3;
222 else
223 n = 2;
224 n = decoct(src+12, n, tp, sizeof tmp - (tp - tmp));
225 if (n == 0) {
226 errno = EMSGSIZE;
227 return (NULL);
228 }
229 tp += strlen(tp);
230 break;
231 }
232 tp += sprintf(tp, "%x", words[i]);
233 }
234
235 /* Was it a trailing run of 0x00's? */
236 if (best.base != -1 && (best.base + best.len) ==
237 (NS_IN6ADDRSZ / NS_INT16SZ))
238 *tp++ = ':';
239 *tp = '\0';
240
241 if (bits != -1)
242 tp += sprintf(tp, "/%u", bits);
243
244 /*
245 * Check for overflow, copy, and we're done.
246 */
247 if ((size_t)(tp - tmp) > size) {
248 errno = EMSGSIZE;
249 return (NULL);
250 }
251 strcpy(dst, tmp);
252 return (dst);
253 }
254