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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.c194
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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 1.1 1997/03/13 19:07:32 downsj 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 1.1 1997/03/13 19:07:32 downsj 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 __P((const u_char *src, char *dst, size_t size));
43static const char *inet_ntop6 __P((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
92 if (sprintf(tmp, fmt, src[0], src[1], src[2], src[3]) > size) {
93 errno = ENOSPC;
94 return (NULL);
95 }
96 strcpy(dst, tmp);
97 return (dst);
98}
99
100/* const char *
101 * inet_ntop6(src, dst, size)
102 * convert IPv6 binary address into presentation (printable) format
103 * author:
104 * Paul Vixie, 1996.
105 */
106static const char *
107inet_ntop6(src, dst, size)
108 const u_char *src;
109 char *dst;
110 size_t size;
111{
112 /*
113 * Note that int32_t and int16_t need only be "at least" large enough
114 * to contain a value of the specified size. On some systems, like
115 * Crays, there is no such thing as an integer variable with 16 bits.
116 * Keep this in mind if you think this function should have been coded
117 * to use pointer overlays. All the world's not a VAX.
118 */
119 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
120 struct { int base, len; } best, cur;
121 u_int words[IN6ADDRSZ / INT16SZ];
122 int i;
123
124 /*
125 * Preprocess:
126 * Copy the input (bytewise) array into a wordwise array.
127 * Find the longest run of 0x00's in src[] for :: shorthanding.
128 */
129 memset(words, '\0', sizeof words);
130 for (i = 0; i < IN6ADDRSZ; i++)
131 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
132 best.base = -1;
133 cur.base = -1;
134 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) {
135 if (words[i] == 0) {
136 if (cur.base == -1)
137 cur.base = i, cur.len = 1;
138 else
139 cur.len++;
140 } else {
141 if (cur.base != -1) {
142 if (best.base == -1 || cur.len > best.len)
143 best = cur;
144 cur.base = -1;
145 }
146 }
147 }
148 if (cur.base != -1) {
149 if (best.base == -1 || cur.len > best.len)
150 best = cur;
151 }
152 if (best.base != -1 && best.len < 2)
153 best.base = -1;
154
155 /*
156 * Format the result.
157 */
158 tp = tmp;
159 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) {
160 /* Are we inside the best run of 0x00's? */
161 if (best.base != -1 && i >= best.base &&
162 i < (best.base + best.len)) {
163 if (i == best.base)
164 *tp++ = ':';
165 continue;
166 }
167 /* Are we following an initial run of 0x00s or any real hex? */
168 if (i != 0)
169 *tp++ = ':';
170 /* Is this address an encapsulated IPv4? */
171 if (i == 6 && best.base == 0 &&
172 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
173 if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
174 return (NULL);
175 tp += strlen(tp);
176 break;
177 }
178 tp += sprintf(tp, "%x", words[i]);
179 }
180 /* Was it a trailing run of 0x00's? */
181 if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ))
182 *tp++ = ':';
183 *tp++ = '\0';
184
185 /*
186 * Check for overflow, copy, and we're done.
187 */
188 if ((size_t)(tp - tmp) > size) {
189 errno = ENOSPC;
190 return (NULL);
191 }
192 strcpy(dst, tmp);
193 return (dst);
194}
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