blob: 3bea519afb8c4fa9e46bf27eb1c177e78afc220a [file] [log] [blame]
Damien Miller71eb0c12002-09-11 10:29:11 +10001/* $OpenBSD: inet_ntop.c,v 1.5 2002/08/23 16:27:31 itojun Exp $ */
Tim Ricee991e3c2001-08-07 15:29:07 -07002
3/* Copyright (c) 1996 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 INTERNET SOFTWARE CONSORTIUM DISCLAIMS
10 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
11 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
12 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
13 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
14 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
15 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
16 * SOFTWARE.
17 */
18
Ben Lindstromdd21fe92002-06-27 18:23:20 +000019#include "includes.h"
Tim Ricee991e3c2001-08-07 15:29:07 -070020
21#ifndef HAVE_INET_NTOP
22
23#if defined(LIBC_SCCS) && !defined(lint)
24#if 0
25static char rcsid[] = "$From: inet_ntop.c,v 8.7 1996/08/05 08:41:18 vixie Exp $";
26#else
Damien Miller71eb0c12002-09-11 10:29:11 +100027static char rcsid[] = "$OpenBSD: inet_ntop.c,v 1.5 2002/08/23 16:27:31 itojun Exp $";
Tim Ricee991e3c2001-08-07 15:29:07 -070028#endif
29#endif /* LIBC_SCCS and not lint */
30
31#include <sys/param.h>
32#include <sys/types.h>
33#include <sys/socket.h>
34#include "openbsd-compat/fake-socket.h"
35#include <netinet/in.h>
36#include <arpa/inet.h>
37#ifndef HAVE_CYGWIN
38#include <arpa/nameser.h>
39#endif
40#include <string.h>
41#include <errno.h>
42#include <stdio.h>
43
44#ifndef IN6ADDRSZ
45#define IN6ADDRSZ 16 /* IPv6 T_AAAA */
46#endif
47
48#ifndef INT16SZ
49#define INT16SZ 2 /* for systems without 16-bit ints */
50#endif
51
52/*
53 * WARNING: Don't even consider trying to compile this on a system where
54 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
55 */
56
Damien Miller71eb0c12002-09-11 10:29:11 +100057static const char *inet_ntop4(const u_char *src, char *dst, size_t size);
58static const char *inet_ntop6(const u_char *src, char *dst, size_t size);
Tim Ricee991e3c2001-08-07 15:29:07 -070059
60/* char *
61 * inet_ntop(af, src, dst, size)
62 * convert a network format address to presentation format.
63 * return:
64 * pointer to presentation format address (`dst'), or NULL (see errno).
65 * author:
66 * Paul Vixie, 1996.
67 */
68const char *
69inet_ntop(af, src, dst, size)
70 int af;
71 const void *src;
72 char *dst;
73 size_t size;
74{
75 switch (af) {
76 case AF_INET:
77 return (inet_ntop4(src, dst, size));
78 case AF_INET6:
79 return (inet_ntop6(src, dst, size));
80 default:
81 errno = EAFNOSUPPORT;
82 return (NULL);
83 }
84 /* NOTREACHED */
85}
86
87/* const char *
88 * inet_ntop4(src, dst, size)
89 * format an IPv4 address, more or less like inet_ntoa()
90 * return:
91 * `dst' (as a const)
92 * notes:
93 * (1) uses no statics
94 * (2) takes a u_char* not an in_addr as input
95 * author:
96 * Paul Vixie, 1996.
97 */
98static const char *
99inet_ntop4(src, dst, size)
100 const u_char *src;
101 char *dst;
102 size_t size;
103{
104 static const char fmt[] = "%u.%u.%u.%u";
105 char tmp[sizeof "255.255.255.255"];
Damien Miller71eb0c12002-09-11 10:29:11 +1000106 int l;
Tim Ricee991e3c2001-08-07 15:29:07 -0700107
Damien Miller71eb0c12002-09-11 10:29:11 +1000108 l = snprintf(tmp, size, fmt, src[0], src[1], src[2], src[3]);
109 if (l <= 0 || l >= size) {
Tim Ricee991e3c2001-08-07 15:29:07 -0700110 errno = ENOSPC;
111 return (NULL);
112 }
Damien Miller71eb0c12002-09-11 10:29:11 +1000113 strlcpy(dst, tmp, size);
Tim Ricee991e3c2001-08-07 15:29:07 -0700114 return (dst);
115}
116
117/* const char *
118 * inet_ntop6(src, dst, size)
119 * convert IPv6 binary address into presentation (printable) format
120 * author:
121 * Paul Vixie, 1996.
122 */
123static const char *
124inet_ntop6(src, dst, size)
125 const u_char *src;
126 char *dst;
127 size_t size;
128{
129 /*
130 * Note that int32_t and int16_t need only be "at least" large enough
131 * to contain a value of the specified size. On some systems, like
132 * Crays, there is no such thing as an integer variable with 16 bits.
133 * Keep this in mind if you think this function should have been coded
134 * to use pointer overlays. All the world's not a VAX.
135 */
Damien Miller71eb0c12002-09-11 10:29:11 +1000136 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"];
137 char *tp, *ep;
Tim Ricee991e3c2001-08-07 15:29:07 -0700138 struct { int base, len; } best, cur;
139 u_int words[IN6ADDRSZ / INT16SZ];
140 int i;
Damien Miller71eb0c12002-09-11 10:29:11 +1000141 int advance;
Tim Ricee991e3c2001-08-07 15:29:07 -0700142
143 /*
144 * Preprocess:
145 * Copy the input (bytewise) array into a wordwise array.
146 * Find the longest run of 0x00's in src[] for :: shorthanding.
147 */
148 memset(words, '\0', sizeof words);
149 for (i = 0; i < IN6ADDRSZ; i++)
150 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
151 best.base = -1;
152 cur.base = -1;
153 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) {
154 if (words[i] == 0) {
155 if (cur.base == -1)
156 cur.base = i, cur.len = 1;
157 else
158 cur.len++;
159 } else {
160 if (cur.base != -1) {
161 if (best.base == -1 || cur.len > best.len)
162 best = cur;
163 cur.base = -1;
164 }
165 }
166 }
167 if (cur.base != -1) {
168 if (best.base == -1 || cur.len > best.len)
169 best = cur;
170 }
171 if (best.base != -1 && best.len < 2)
172 best.base = -1;
173
174 /*
175 * Format the result.
176 */
177 tp = tmp;
Damien Miller71eb0c12002-09-11 10:29:11 +1000178 ep = tmp + sizeof(tmp);
179 for (i = 0; i < (IN6ADDRSZ / INT16SZ) && tp < ep; i++) {
Tim Ricee991e3c2001-08-07 15:29:07 -0700180 /* Are we inside the best run of 0x00's? */
181 if (best.base != -1 && i >= best.base &&
182 i < (best.base + best.len)) {
Damien Miller71eb0c12002-09-11 10:29:11 +1000183 if (i == best.base) {
184 if (tp + 1 >= ep)
185 return (NULL);
Tim Ricee991e3c2001-08-07 15:29:07 -0700186 *tp++ = ':';
Damien Miller71eb0c12002-09-11 10:29:11 +1000187 }
Tim Ricee991e3c2001-08-07 15:29:07 -0700188 continue;
189 }
190 /* Are we following an initial run of 0x00s or any real hex? */
Damien Miller71eb0c12002-09-11 10:29:11 +1000191 if (i != 0) {
192 if (tp + 1 >= ep)
193 return (NULL);
Tim Ricee991e3c2001-08-07 15:29:07 -0700194 *tp++ = ':';
Damien Miller71eb0c12002-09-11 10:29:11 +1000195 }
Tim Ricee991e3c2001-08-07 15:29:07 -0700196 /* Is this address an encapsulated IPv4? */
197 if (i == 6 && best.base == 0 &&
198 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
Damien Miller71eb0c12002-09-11 10:29:11 +1000199 if (!inet_ntop4(src+12, tp, (size_t)(ep - tp)))
Tim Ricee991e3c2001-08-07 15:29:07 -0700200 return (NULL);
201 tp += strlen(tp);
202 break;
203 }
Damien Miller71eb0c12002-09-11 10:29:11 +1000204 advance = snprintf(tp, ep - tp, "%x", words[i]);
205 if (advance <= 0 || advance >= ep - tp)
206 return (NULL);
207 tp += advance;
Tim Ricee991e3c2001-08-07 15:29:07 -0700208 }
209 /* Was it a trailing run of 0x00's? */
Damien Miller71eb0c12002-09-11 10:29:11 +1000210 if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ)) {
211 if (tp + 1 >= ep)
212 return (NULL);
Tim Ricee991e3c2001-08-07 15:29:07 -0700213 *tp++ = ':';
Damien Miller71eb0c12002-09-11 10:29:11 +1000214 }
215 if (tp + 1 >= ep)
216 return (NULL);
Tim Ricee991e3c2001-08-07 15:29:07 -0700217 *tp++ = '\0';
218
219 /*
220 * Check for overflow, copy, and we're done.
221 */
222 if ((size_t)(tp - tmp) > size) {
223 errno = ENOSPC;
224 return (NULL);
225 }
Damien Miller71eb0c12002-09-11 10:29:11 +1000226 strlcpy(dst, tmp, size);
Tim Ricee991e3c2001-08-07 15:29:07 -0700227 return (dst);
228}
229
230#endif /* !HAVE_INET_NTOP */