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8912421c LC |
1 | /* inet_ntop.c -- convert IPv4 and IPv6 addresses from binary to text form |
2 | ||
3 | Copyright (C) 2005, 2006, 2008, 2009 Free Software Foundation, Inc. | |
4 | ||
5 | This program is free software; you can redistribute it and/or modify | |
6 | it under the terms of the GNU Lesser General Public License as published by | |
7 | the Free Software Foundation; either version 2, or (at your option) | |
8 | any later version. | |
9 | ||
10 | This program is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | GNU Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public License | |
16 | along with this program; if not, write to the Free Software Foundation, | |
17 | Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ | |
18 | ||
19 | /* | |
20 | * Copyright (c) 1996-1999 by Internet Software Consortium. | |
21 | * | |
22 | * Permission to use, copy, modify, and distribute this software for any | |
23 | * purpose with or without fee is hereby granted, provided that the above | |
24 | * copyright notice and this permission notice appear in all copies. | |
25 | * | |
26 | * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS | |
27 | * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES | |
28 | * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE | |
29 | * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL | |
30 | * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR | |
31 | * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS | |
32 | * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS | |
33 | * SOFTWARE. | |
34 | */ | |
35 | ||
36 | #include <config.h> | |
37 | ||
38 | /* Specification. */ | |
39 | #include <arpa/inet.h> | |
40 | ||
41 | #include <stdio.h> | |
42 | #include <string.h> | |
43 | #include <errno.h> | |
44 | ||
45 | #define NS_IN6ADDRSZ 16 | |
46 | #define NS_INT16SZ 2 | |
47 | ||
48 | /* | |
49 | * WARNING: Don't even consider trying to compile this on a system where | |
50 | * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX. | |
51 | */ | |
52 | typedef int verify_int_size[2 * sizeof (int) - 7]; | |
53 | ||
54 | static const char *inet_ntop4 (const unsigned char *src, char *dst, socklen_t size); | |
55 | #if HAVE_IPV6 | |
56 | static const char *inet_ntop6 (const unsigned char *src, char *dst, socklen_t size); | |
57 | #endif | |
58 | ||
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 (int af, const void *restrict src, | |
70 | char *restrict dst, socklen_t cnt) | |
71 | { | |
72 | switch (af) | |
73 | { | |
74 | #if HAVE_IPV4 | |
75 | case AF_INET: | |
76 | return (inet_ntop4 (src, dst, cnt)); | |
77 | #endif | |
78 | ||
79 | #if HAVE_IPV6 | |
80 | case AF_INET6: | |
81 | return (inet_ntop6 (src, dst, cnt)); | |
82 | #endif | |
83 | ||
84 | default: | |
85 | errno = EAFNOSUPPORT; | |
86 | return (NULL); | |
87 | } | |
88 | /* NOTREACHED */ | |
89 | } | |
90 | ||
91 | /* const char * | |
92 | * inet_ntop4(src, dst, size) | |
93 | * format an IPv4 address | |
94 | * return: | |
95 | * `dst' (as a const) | |
96 | * notes: | |
97 | * (1) uses no statics | |
98 | * (2) takes a u_char* not an in_addr as input | |
99 | * author: | |
100 | * Paul Vixie, 1996. | |
101 | */ | |
102 | static const char * | |
103 | inet_ntop4 (const unsigned char *src, char *dst, socklen_t size) | |
104 | { | |
105 | char tmp[sizeof "255.255.255.255"]; | |
106 | int len; | |
107 | ||
108 | len = sprintf (tmp, "%u.%u.%u.%u", src[0], src[1], src[2], src[3]); | |
109 | if (len < 0) | |
110 | return NULL; | |
111 | ||
112 | if (len > size) | |
113 | { | |
114 | errno = ENOSPC; | |
115 | return NULL; | |
116 | } | |
117 | ||
118 | return strcpy (dst, tmp); | |
119 | } | |
120 | ||
121 | #if HAVE_IPV6 | |
122 | ||
123 | /* const char * | |
124 | * inet_ntop6(src, dst, size) | |
125 | * convert IPv6 binary address into presentation (printable) format | |
126 | * author: | |
127 | * Paul Vixie, 1996. | |
128 | */ | |
129 | static const char * | |
130 | inet_ntop6 (const unsigned char *src, char *dst, socklen_t size) | |
131 | { | |
132 | /* | |
133 | * Note that int32_t and int16_t need only be "at least" large enough | |
134 | * to contain a value of the specified size. On some systems, like | |
135 | * Crays, there is no such thing as an integer variable with 16 bits. | |
136 | * Keep this in mind if you think this function should have been coded | |
137 | * to use pointer overlays. All the world's not a VAX. | |
138 | */ | |
139 | char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp; | |
140 | struct | |
141 | { | |
142 | int base, len; | |
143 | } best, cur; | |
144 | unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ]; | |
145 | int i; | |
146 | ||
147 | /* | |
148 | * Preprocess: | |
149 | * Copy the input (bytewise) array into a wordwise array. | |
150 | * Find the longest run of 0x00's in src[] for :: shorthanding. | |
151 | */ | |
152 | memset (words, '\0', sizeof words); | |
153 | for (i = 0; i < NS_IN6ADDRSZ; i += 2) | |
154 | words[i / 2] = (src[i] << 8) | src[i + 1]; | |
155 | best.base = -1; | |
156 | cur.base = -1; | |
157 | for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) | |
158 | { | |
159 | if (words[i] == 0) | |
160 | { | |
161 | if (cur.base == -1) | |
162 | cur.base = i, cur.len = 1; | |
163 | else | |
164 | cur.len++; | |
165 | } | |
166 | else | |
167 | { | |
168 | if (cur.base != -1) | |
169 | { | |
170 | if (best.base == -1 || cur.len > best.len) | |
171 | best = cur; | |
172 | cur.base = -1; | |
173 | } | |
174 | } | |
175 | } | |
176 | if (cur.base != -1) | |
177 | { | |
178 | if (best.base == -1 || cur.len > best.len) | |
179 | best = cur; | |
180 | } | |
181 | if (best.base != -1 && best.len < 2) | |
182 | best.base = -1; | |
183 | ||
184 | /* | |
185 | * Format the result. | |
186 | */ | |
187 | tp = tmp; | |
188 | for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) | |
189 | { | |
190 | /* Are we inside the best run of 0x00's? */ | |
191 | if (best.base != -1 && i >= best.base && i < (best.base + best.len)) | |
192 | { | |
193 | if (i == best.base) | |
194 | *tp++ = ':'; | |
195 | continue; | |
196 | } | |
197 | /* Are we following an initial run of 0x00s or any real hex? */ | |
198 | if (i != 0) | |
199 | *tp++ = ':'; | |
200 | /* Is this address an encapsulated IPv4? */ | |
201 | if (i == 6 && best.base == 0 && | |
202 | (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) | |
203 | { | |
204 | if (!inet_ntop4 (src + 12, tp, sizeof tmp - (tp - tmp))) | |
205 | return (NULL); | |
206 | tp += strlen (tp); | |
207 | break; | |
208 | } | |
209 | { | |
210 | int len = sprintf (tp, "%x", words[i]); | |
211 | if (len < 0) | |
212 | return NULL; | |
213 | tp += len; | |
214 | } | |
215 | } | |
216 | /* Was it a trailing run of 0x00's? */ | |
217 | if (best.base != -1 && (best.base + best.len) == | |
218 | (NS_IN6ADDRSZ / NS_INT16SZ)) | |
219 | *tp++ = ':'; | |
220 | *tp++ = '\0'; | |
221 | ||
222 | /* | |
223 | * Check for overflow, copy, and we're done. | |
224 | */ | |
225 | if ((socklen_t) (tp - tmp) > size) | |
226 | { | |
227 | errno = ENOSPC; | |
228 | return NULL; | |
229 | } | |
230 | ||
231 | return strcpy (dst, tmp); | |
232 | } | |
233 | ||
234 | #endif |