1 /* $NetBSD: inet_net_ntop.c,v 1.1.1.2 2012/09/09 16:07:50 christos Exp $ */
2
3 /*
4 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
5 * Copyright (c) 1996,1999 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 #if defined(LIBC_SCCS) && !defined(lint)
21 static const char rcsid[] = "Id: inet_net_ntop.c,v 1.5 2006/06/20 02:50:14 marka Exp ";
22 #endif
23
24 #include "port_before.h"
25
26 #include <sys/types.h>
27 #include <sys/socket.h>
28 #include <netinet/in.h>
29 #include <arpa/inet.h>
30
31 #include <errno.h>
32 #include <stdio.h>
33 #include <string.h>
34 #include <stdlib.h>
35
36 #include "port_after.h"
37
38 #ifdef SPRINTF_CHAR
39 # define SPRINTF(x) strlen(sprintf/**/x)
40 #else
41 # define SPRINTF(x) ((size_t)sprintf x)
42 #endif
43
44 static char * inet_net_ntop_ipv4 __P((const u_char *src, int bits,
45 char *dst, size_t size));
46 static char * inet_net_ntop_ipv6 __P((const u_char *src, int bits,
47 char *dst, size_t size));
48
49 /*%
50 * char *
51 * inet_net_ntop(af, src, bits, dst, size)
52 * convert network number from network to presentation format.
53 * generates CIDR style result always.
54 * return:
55 * pointer to dst, or NULL if an error occurred (check errno).
56 * author:
57 * Paul Vixie (ISC), July 1996
58 */
59 char *
inet_net_ntop(af,src,bits,dst,size)60 inet_net_ntop(af, src, bits, dst, size)
61 int af;
62 const void *src;
63 int bits;
64 char *dst;
65 size_t size;
66 {
67 switch (af) {
68 case AF_INET:
69 return (inet_net_ntop_ipv4(src, bits, dst, size));
70 case AF_INET6:
71 return (inet_net_ntop_ipv6(src, bits, dst, size));
72 default:
73 errno = EAFNOSUPPORT;
74 return (NULL);
75 }
76 }
77
78 /*%
79 * static char *
80 * inet_net_ntop_ipv4(src, bits, dst, size)
81 * convert IPv4 network number from network to presentation format.
82 * generates CIDR style result always.
83 * return:
84 * pointer to dst, or NULL if an error occurred (check errno).
85 * note:
86 * network byte order assumed. this means 192.5.5.240/28 has
87 * 0b11110000 in its fourth octet.
88 * author:
89 * Paul Vixie (ISC), July 1996
90 */
91 static char *
inet_net_ntop_ipv4(src,bits,dst,size)92 inet_net_ntop_ipv4(src, bits, dst, size)
93 const u_char *src;
94 int bits;
95 char *dst;
96 size_t size;
97 {
98 char *odst = dst;
99 char *t;
100 u_int m;
101 int b;
102
103 if (bits < 0 || bits > 32) {
104 errno = EINVAL;
105 return (NULL);
106 }
107
108 if (bits == 0) {
109 if (size < sizeof "0")
110 goto emsgsize;
111 *dst++ = '0';
112 size--;
113 *dst = '\0';
114 }
115
116 /* Format whole octets. */
117 for (b = bits / 8; b > 0; b--) {
118 if (size <= sizeof "255.")
119 goto emsgsize;
120 t = dst;
121 dst += SPRINTF((dst, "%u", *src++));
122 if (b > 1) {
123 *dst++ = '.';
124 *dst = '\0';
125 }
126 size -= (size_t)(dst - t);
127 }
128
129 /* Format partial octet. */
130 b = bits % 8;
131 if (b > 0) {
132 if (size <= sizeof ".255")
133 goto emsgsize;
134 t = dst;
135 if (dst != odst)
136 *dst++ = '.';
137 m = ((1 << b) - 1) << (8 - b);
138 dst += SPRINTF((dst, "%u", *src & m));
139 size -= (size_t)(dst - t);
140 }
141
142 /* Format CIDR /width. */
143 if (size <= sizeof "/32")
144 goto emsgsize;
145 dst += SPRINTF((dst, "/%u", bits));
146 return (odst);
147
148 emsgsize:
149 errno = EMSGSIZE;
150 return (NULL);
151 }
152
153 /*%
154 * static char *
155 * inet_net_ntop_ipv6(src, bits, fakebits, dst, size)
156 * convert IPv6 network number from network to presentation format.
157 * generates CIDR style result always. Picks the shortest representation
158 * unless the IP is really IPv4.
159 * always prints specified number of bits (bits).
160 * return:
161 * pointer to dst, or NULL if an error occurred (check errno).
162 * note:
163 * network byte order assumed. this means 192.5.5.240/28 has
164 * 0x11110000 in its fourth octet.
165 * author:
166 * Vadim Kogan (UCB), June 2001
167 * Original version (IPv4) by Paul Vixie (ISC), July 1996
168 */
169
170 static char *
inet_net_ntop_ipv6(const u_char * src,int bits,char * dst,size_t size)171 inet_net_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size) {
172 u_int m;
173 int b;
174 int p;
175 int zero_s, zero_l, tmp_zero_s, tmp_zero_l;
176 int i;
177 int is_ipv4 = 0;
178 unsigned char inbuf[16];
179 char outbuf[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255/128")];
180 char *cp;
181 int words;
182 u_char *s;
183
184 if (bits < 0 || bits > 128) {
185 errno = EINVAL;
186 return (NULL);
187 }
188
189 cp = outbuf;
190
191 if (bits == 0) {
192 *cp++ = ':';
193 *cp++ = ':';
194 *cp = '\0';
195 } else {
196 /* Copy src to private buffer. Zero host part. */
197 p = (bits + 7) / 8;
198 memcpy(inbuf, src, p);
199 memset(inbuf + p, 0, 16 - p);
200 b = bits % 8;
201 if (b != 0) {
202 m = ~0 << (8 - b);
203 inbuf[p-1] &= m;
204 }
205
206 s = inbuf;
207
208 /* how many words need to be displayed in output */
209 words = (bits + 15) / 16;
210 if (words == 1)
211 words = 2;
212
213 /* Find the longest substring of zero's */
214 zero_s = zero_l = tmp_zero_s = tmp_zero_l = 0;
215 for (i = 0; i < (words * 2); i += 2) {
216 if ((s[i] | s[i+1]) == 0) {
217 if (tmp_zero_l == 0)
218 tmp_zero_s = i / 2;
219 tmp_zero_l++;
220 } else {
221 if (tmp_zero_l && zero_l < tmp_zero_l) {
222 zero_s = tmp_zero_s;
223 zero_l = tmp_zero_l;
224 tmp_zero_l = 0;
225 }
226 }
227 }
228
229 if (tmp_zero_l && zero_l < tmp_zero_l) {
230 zero_s = tmp_zero_s;
231 zero_l = tmp_zero_l;
232 }
233
234 if (zero_l != words && zero_s == 0 && ((zero_l == 6) ||
235 ((zero_l == 5 && s[10] == 0xff && s[11] == 0xff) ||
236 ((zero_l == 7 && s[14] != 0 && s[15] != 1)))))
237 is_ipv4 = 1;
238
239 /* Format whole words. */
240 for (p = 0; p < words; p++) {
241 if (zero_l != 0 && p >= zero_s && p < zero_s + zero_l) {
242 /* Time to skip some zeros */
243 if (p == zero_s)
244 *cp++ = ':';
245 if (p == words - 1)
246 *cp++ = ':';
247 s++;
248 s++;
249 continue;
250 }
251
252 if (is_ipv4 && p > 5 ) {
253 *cp++ = (p == 6) ? ':' : '.';
254 cp += SPRINTF((cp, "%u", *s++));
255 /* we can potentially drop the last octet */
256 if (p != 7 || bits > 120) {
257 *cp++ = '.';
258 cp += SPRINTF((cp, "%u", *s++));
259 }
260 } else {
261 if (cp != outbuf)
262 *cp++ = ':';
263 cp += SPRINTF((cp, "%x", *s * 256 + s[1]));
264 s += 2;
265 }
266 }
267 }
268 /* Format CIDR /width. */
269 sprintf(cp, "/%u", bits);
270 if (strlen(outbuf) + 1 > size)
271 goto emsgsize;
272 strcpy(dst, outbuf);
273
274 return (dst);
275
276 emsgsize:
277 errno = EMSGSIZE;
278 return (NULL);
279 }
280
281 /*! \file */
282