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ac8802eb | 1 | /* $OpenBSD: inet_ntop.c,v 1.5 2002/08/23 16:27:31 itojun Exp $ */ |
a704dd54 | 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 | ||
17962c40 | 19 | #include "includes.h" |
a704dd54 | 20 | |
21 | #ifndef HAVE_INET_NTOP | |
22 | ||
23 | #if defined(LIBC_SCCS) && !defined(lint) | |
24 | #if 0 | |
25 | static char rcsid[] = "$From: inet_ntop.c,v 8.7 1996/08/05 08:41:18 vixie Exp $"; | |
26 | #else | |
ac8802eb | 27 | static char rcsid[] = "$OpenBSD: inet_ntop.c,v 1.5 2002/08/23 16:27:31 itojun Exp $"; |
a704dd54 | 28 | #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 | ||
ac8802eb | 57 | static const char *inet_ntop4(const u_char *src, char *dst, size_t size); |
58 | static const char *inet_ntop6(const u_char *src, char *dst, size_t size); | |
a704dd54 | 59 | |
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 | */ | |
68 | const char * | |
69 | inet_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 | */ | |
98 | static const char * | |
99 | inet_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"]; | |
ac8802eb | 106 | int l; |
a704dd54 | 107 | |
ac8802eb | 108 | l = snprintf(tmp, size, fmt, src[0], src[1], src[2], src[3]); |
109 | if (l <= 0 || l >= size) { | |
a704dd54 | 110 | errno = ENOSPC; |
111 | return (NULL); | |
112 | } | |
ac8802eb | 113 | strlcpy(dst, tmp, size); |
a704dd54 | 114 | 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 | */ | |
123 | static const char * | |
124 | inet_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 | */ | |
ac8802eb | 136 | char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"]; |
137 | char *tp, *ep; | |
a704dd54 | 138 | struct { int base, len; } best, cur; |
139 | u_int words[IN6ADDRSZ / INT16SZ]; | |
140 | int i; | |
ac8802eb | 141 | int advance; |
a704dd54 | 142 | |
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; | |
ac8802eb | 178 | ep = tmp + sizeof(tmp); |
179 | for (i = 0; i < (IN6ADDRSZ / INT16SZ) && tp < ep; i++) { | |
a704dd54 | 180 | /* Are we inside the best run of 0x00's? */ |
181 | if (best.base != -1 && i >= best.base && | |
182 | i < (best.base + best.len)) { | |
ac8802eb | 183 | if (i == best.base) { |
184 | if (tp + 1 >= ep) | |
185 | return (NULL); | |
a704dd54 | 186 | *tp++ = ':'; |
ac8802eb | 187 | } |
a704dd54 | 188 | continue; |
189 | } | |
190 | /* Are we following an initial run of 0x00s or any real hex? */ | |
ac8802eb | 191 | if (i != 0) { |
192 | if (tp + 1 >= ep) | |
193 | return (NULL); | |
a704dd54 | 194 | *tp++ = ':'; |
ac8802eb | 195 | } |
a704dd54 | 196 | /* Is this address an encapsulated IPv4? */ |
197 | if (i == 6 && best.base == 0 && | |
198 | (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) { | |
ac8802eb | 199 | if (!inet_ntop4(src+12, tp, (size_t)(ep - tp))) |
a704dd54 | 200 | return (NULL); |
201 | tp += strlen(tp); | |
202 | break; | |
203 | } | |
ac8802eb | 204 | advance = snprintf(tp, ep - tp, "%x", words[i]); |
205 | if (advance <= 0 || advance >= ep - tp) | |
206 | return (NULL); | |
207 | tp += advance; | |
a704dd54 | 208 | } |
209 | /* Was it a trailing run of 0x00's? */ | |
ac8802eb | 210 | if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ)) { |
211 | if (tp + 1 >= ep) | |
212 | return (NULL); | |
a704dd54 | 213 | *tp++ = ':'; |
ac8802eb | 214 | } |
215 | if (tp + 1 >= ep) | |
216 | return (NULL); | |
a704dd54 | 217 | *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 | } | |
ac8802eb | 226 | strlcpy(dst, tmp, size); |
a704dd54 | 227 | return (dst); |
228 | } | |
229 | ||
230 | #endif /* !HAVE_INET_NTOP */ |