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path: root/src/lib/libc/net/inet_ntop.c
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Diffstat (limited to 'src/lib/libc/net/inet_ntop.c')
-rw-r--r--src/lib/libc/net/inet_ntop.c213
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diff --git a/src/lib/libc/net/inet_ntop.c b/src/lib/libc/net/inet_ntop.c
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1/* $OpenBSD: inet_ntop.c,v 1.5 2002/08/23 16:27:31 itojun Exp $ */
2
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
19#if defined(LIBC_SCCS) && !defined(lint)
20#if 0
21static char rcsid[] = "$From: inet_ntop.c,v 8.7 1996/08/05 08:41:18 vixie Exp $";
22#else
23static char rcsid[] = "$OpenBSD: inet_ntop.c,v 1.5 2002/08/23 16:27:31 itojun Exp $";
24#endif
25#endif /* LIBC_SCCS and not lint */
26
27#include <sys/param.h>
28#include <sys/types.h>
29#include <sys/socket.h>
30#include <netinet/in.h>
31#include <arpa/inet.h>
32#include <arpa/nameser.h>
33#include <string.h>
34#include <errno.h>
35#include <stdio.h>
36
37/*
38 * WARNING: Don't even consider trying to compile this on a system where
39 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
40 */
41
42static const char *inet_ntop4(const u_char *src, char *dst, size_t size);
43static const char *inet_ntop6(const u_char *src, char *dst, size_t size);
44
45/* char *
46 * inet_ntop(af, src, dst, size)
47 * convert a network format address to presentation format.
48 * return:
49 * pointer to presentation format address (`dst'), or NULL (see errno).
50 * author:
51 * Paul Vixie, 1996.
52 */
53const char *
54inet_ntop(af, src, dst, size)
55 int af;
56 const void *src;
57 char *dst;
58 size_t size;
59{
60 switch (af) {
61 case AF_INET:
62 return (inet_ntop4(src, dst, size));
63 case AF_INET6:
64 return (inet_ntop6(src, dst, size));
65 default:
66 errno = EAFNOSUPPORT;
67 return (NULL);
68 }
69 /* NOTREACHED */
70}
71
72/* const char *
73 * inet_ntop4(src, dst, size)
74 * format an IPv4 address, more or less like inet_ntoa()
75 * return:
76 * `dst' (as a const)
77 * notes:
78 * (1) uses no statics
79 * (2) takes a u_char* not an in_addr as input
80 * author:
81 * Paul Vixie, 1996.
82 */
83static const char *
84inet_ntop4(src, dst, size)
85 const u_char *src;
86 char *dst;
87 size_t size;
88{
89 static const char fmt[] = "%u.%u.%u.%u";
90 char tmp[sizeof "255.255.255.255"];
91 int l;
92
93 l = snprintf(tmp, size, fmt, src[0], src[1], src[2], src[3]);
94 if (l <= 0 || l >= size) {
95 errno = ENOSPC;
96 return (NULL);
97 }
98 strlcpy(dst, tmp, size);
99 return (dst);
100}
101
102/* const char *
103 * inet_ntop6(src, dst, size)
104 * convert IPv6 binary address into presentation (printable) format
105 * author:
106 * Paul Vixie, 1996.
107 */
108static const char *
109inet_ntop6(src, dst, size)
110 const u_char *src;
111 char *dst;
112 size_t size;
113{
114 /*
115 * Note that int32_t and int16_t need only be "at least" large enough
116 * to contain a value of the specified size. On some systems, like
117 * Crays, there is no such thing as an integer variable with 16 bits.
118 * Keep this in mind if you think this function should have been coded
119 * to use pointer overlays. All the world's not a VAX.
120 */
121 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"];
122 char *tp, *ep;
123 struct { int base, len; } best, cur;
124 u_int words[IN6ADDRSZ / INT16SZ];
125 int i;
126 int advance;
127
128 /*
129 * Preprocess:
130 * Copy the input (bytewise) array into a wordwise array.
131 * Find the longest run of 0x00's in src[] for :: shorthanding.
132 */
133 memset(words, '\0', sizeof words);
134 for (i = 0; i < IN6ADDRSZ; i++)
135 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
136 best.base = -1;
137 cur.base = -1;
138 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) {
139 if (words[i] == 0) {
140 if (cur.base == -1)
141 cur.base = i, cur.len = 1;
142 else
143 cur.len++;
144 } else {
145 if (cur.base != -1) {
146 if (best.base == -1 || cur.len > best.len)
147 best = cur;
148 cur.base = -1;
149 }
150 }
151 }
152 if (cur.base != -1) {
153 if (best.base == -1 || cur.len > best.len)
154 best = cur;
155 }
156 if (best.base != -1 && best.len < 2)
157 best.base = -1;
158
159 /*
160 * Format the result.
161 */
162 tp = tmp;
163 ep = tmp + sizeof(tmp);
164 for (i = 0; i < (IN6ADDRSZ / INT16SZ) && tp < ep; i++) {
165 /* Are we inside the best run of 0x00's? */
166 if (best.base != -1 && i >= best.base &&
167 i < (best.base + best.len)) {
168 if (i == best.base) {
169 if (tp + 1 >= ep)
170 return (NULL);
171 *tp++ = ':';
172 }
173 continue;
174 }
175 /* Are we following an initial run of 0x00s or any real hex? */
176 if (i != 0) {
177 if (tp + 1 >= ep)
178 return (NULL);
179 *tp++ = ':';
180 }
181 /* Is this address an encapsulated IPv4? */
182 if (i == 6 && best.base == 0 &&
183 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
184 if (!inet_ntop4(src+12, tp, (size_t)(ep - tp)))
185 return (NULL);
186 tp += strlen(tp);
187 break;
188 }
189 advance = snprintf(tp, ep - tp, "%x", words[i]);
190 if (advance <= 0 || advance >= ep - tp)
191 return (NULL);
192 tp += advance;
193 }
194 /* Was it a trailing run of 0x00's? */
195 if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ)) {
196 if (tp + 1 >= ep)
197 return (NULL);
198 *tp++ = ':';
199 }
200 if (tp + 1 >= ep)
201 return (NULL);
202 *tp++ = '\0';
203
204 /*
205 * Check for overflow, copy, and we're done.
206 */
207 if ((size_t)(tp - tmp) > size) {
208 errno = ENOSPC;
209 return (NULL);
210 }
211 strlcpy(dst, tmp, size);
212 return (dst);
213}