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1 | /* inet_ntop.c -- convert IPv4 and IPv6 addresses from binary to text form |
2 | ||
3 | Copyright (C) 2005-2006, 2008-2016 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 General Public License as published by | |
7 | the Free Software Foundation; either version 3, 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 General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU General Public License | |
16 | along with this program; if not, see <http://www.gnu.org/licenses/>. */ | |
17 | ||
18 | /* | |
19 | * Copyright (c) 1996-1999 by Internet Software Consortium. | |
20 | * | |
21 | * Permission to use, copy, modify, and distribute this software for any | |
22 | * purpose with or without fee is hereby granted, provided that the above | |
23 | * copyright notice and this permission notice appear in all copies. | |
24 | * | |
25 | * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS | |
26 | * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES | |
27 | * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE | |
28 | * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL | |
29 | * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR | |
30 | * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS | |
31 | * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS | |
32 | * SOFTWARE. | |
33 | */ | |
34 | ||
35 | #include <config.h> | |
36 | ||
37 | /* Specification. */ | |
38 | #include <arpa/inet.h> | |
39 | ||
40 | /* Use this to suppress gcc's "...may be used before initialized" warnings. | |
41 | Beware: The Code argument must not contain commas. */ | |
42 | #ifndef IF_LINT | |
43 | # if defined GCC_LINT || defined lint | |
44 | # define IF_LINT(Code) Code | |
45 | # else | |
46 | # define IF_LINT(Code) /* empty */ | |
47 | # endif | |
48 | #endif | |
49 | ||
50 | #if HAVE_DECL_INET_NTOP | |
51 | ||
52 | # undef inet_ntop | |
53 | ||
54 | const char * | |
55 | rpl_inet_ntop (int af, const void *restrict src, | |
56 | char *restrict dst, socklen_t cnt) | |
57 | { | |
58 | return inet_ntop (af, src, dst, cnt); | |
59 | } | |
60 | ||
61 | #else | |
62 | ||
63 | # include <stdio.h> | |
64 | # include <string.h> | |
65 | # include <errno.h> | |
66 | ||
67 | # define NS_IN6ADDRSZ 16 | |
68 | # define NS_INT16SZ 2 | |
69 | ||
70 | /* | |
71 | * WARNING: Don't even consider trying to compile this on a system where | |
72 | * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX. | |
73 | */ | |
74 | typedef int verify_int_size[4 <= sizeof (int) ? 1 : -1]; | |
75 | ||
76 | static const char *inet_ntop4 (const unsigned char *src, char *dst, socklen_t size); | |
77 | # if HAVE_IPV6 | |
78 | static const char *inet_ntop6 (const unsigned char *src, char *dst, socklen_t size); | |
79 | # endif | |
80 | ||
81 | ||
82 | /* char * | |
83 | * inet_ntop(af, src, dst, size) | |
84 | * convert a network format address to presentation format. | |
85 | * return: | |
86 | * pointer to presentation format address ('dst'), or NULL (see errno). | |
87 | * author: | |
88 | * Paul Vixie, 1996. | |
89 | */ | |
90 | const char * | |
91 | inet_ntop (int af, const void *restrict src, | |
92 | char *restrict dst, socklen_t cnt) | |
93 | { | |
94 | switch (af) | |
95 | { | |
96 | # if HAVE_IPV4 | |
97 | case AF_INET: | |
98 | return (inet_ntop4 (src, dst, cnt)); | |
99 | # endif | |
100 | ||
101 | # if HAVE_IPV6 | |
102 | case AF_INET6: | |
103 | return (inet_ntop6 (src, dst, cnt)); | |
104 | # endif | |
105 | ||
106 | default: | |
107 | errno = EAFNOSUPPORT; | |
108 | return (NULL); | |
109 | } | |
110 | /* NOTREACHED */ | |
111 | } | |
112 | ||
113 | /* const char * | |
114 | * inet_ntop4(src, dst, size) | |
115 | * format an IPv4 address | |
116 | * return: | |
117 | * 'dst' (as a const) | |
118 | * notes: | |
119 | * (1) uses no statics | |
120 | * (2) takes a u_char* not an in_addr as input | |
121 | * author: | |
122 | * Paul Vixie, 1996. | |
123 | */ | |
124 | static const char * | |
125 | inet_ntop4 (const unsigned char *src, char *dst, socklen_t size) | |
126 | { | |
127 | char tmp[sizeof "255.255.255.255"]; | |
128 | int len; | |
129 | ||
130 | len = sprintf (tmp, "%u.%u.%u.%u", src[0], src[1], src[2], src[3]); | |
131 | if (len < 0) | |
132 | return NULL; | |
133 | ||
134 | if (len > size) | |
135 | { | |
136 | errno = ENOSPC; | |
137 | return NULL; | |
138 | } | |
139 | ||
140 | return strcpy (dst, tmp); | |
141 | } | |
142 | ||
143 | # if HAVE_IPV6 | |
144 | ||
145 | /* const char * | |
146 | * inet_ntop6(src, dst, size) | |
147 | * convert IPv6 binary address into presentation (printable) format | |
148 | * author: | |
149 | * Paul Vixie, 1996. | |
150 | */ | |
151 | static const char * | |
152 | inet_ntop6 (const unsigned char *src, char *dst, socklen_t size) | |
153 | { | |
154 | /* | |
155 | * Note that int32_t and int16_t need only be "at least" large enough | |
156 | * to contain a value of the specified size. On some systems, like | |
157 | * Crays, there is no such thing as an integer variable with 16 bits. | |
158 | * Keep this in mind if you think this function should have been coded | |
159 | * to use pointer overlays. All the world's not a VAX. | |
160 | */ | |
161 | char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp; | |
162 | struct | |
163 | { | |
164 | int base, len; | |
165 | } best, cur; | |
166 | unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ]; | |
167 | int i; | |
168 | ||
169 | /* | |
170 | * Preprocess: | |
171 | * Copy the input (bytewise) array into a wordwise array. | |
172 | * Find the longest run of 0x00's in src[] for :: shorthanding. | |
173 | */ | |
174 | memset (words, '\0', sizeof words); | |
175 | for (i = 0; i < NS_IN6ADDRSZ; i += 2) | |
176 | words[i / 2] = (src[i] << 8) | src[i + 1]; | |
177 | best.base = -1; | |
178 | cur.base = -1; | |
179 | IF_LINT(best.len = 0); | |
180 | IF_LINT(cur.len = 0); | |
181 | for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) | |
182 | { | |
183 | if (words[i] == 0) | |
184 | { | |
185 | if (cur.base == -1) | |
186 | cur.base = i, cur.len = 1; | |
187 | else | |
188 | cur.len++; | |
189 | } | |
190 | else | |
191 | { | |
192 | if (cur.base != -1) | |
193 | { | |
194 | if (best.base == -1 || cur.len > best.len) | |
195 | best = cur; | |
196 | cur.base = -1; | |
197 | } | |
198 | } | |
199 | } | |
200 | if (cur.base != -1) | |
201 | { | |
202 | if (best.base == -1 || cur.len > best.len) | |
203 | best = cur; | |
204 | } | |
205 | if (best.base != -1 && best.len < 2) | |
206 | best.base = -1; | |
207 | ||
208 | /* | |
209 | * Format the result. | |
210 | */ | |
211 | tp = tmp; | |
212 | for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) | |
213 | { | |
214 | /* Are we inside the best run of 0x00's? */ | |
215 | if (best.base != -1 && i >= best.base && i < (best.base + best.len)) | |
216 | { | |
217 | if (i == best.base) | |
218 | *tp++ = ':'; | |
219 | continue; | |
220 | } | |
221 | /* Are we following an initial run of 0x00s or any real hex? */ | |
222 | if (i != 0) | |
223 | *tp++ = ':'; | |
224 | /* Is this address an encapsulated IPv4? */ | |
225 | if (i == 6 && best.base == 0 && | |
226 | (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) | |
227 | { | |
228 | if (!inet_ntop4 (src + 12, tp, sizeof tmp - (tp - tmp))) | |
229 | return (NULL); | |
230 | tp += strlen (tp); | |
231 | break; | |
232 | } | |
233 | { | |
234 | int len = sprintf (tp, "%x", words[i]); | |
235 | if (len < 0) | |
236 | return NULL; | |
237 | tp += len; | |
238 | } | |
239 | } | |
240 | /* Was it a trailing run of 0x00's? */ | |
241 | if (best.base != -1 && (best.base + best.len) == | |
242 | (NS_IN6ADDRSZ / NS_INT16SZ)) | |
243 | *tp++ = ':'; | |
244 | *tp++ = '\0'; | |
245 | ||
246 | /* | |
247 | * Check for overflow, copy, and we're done. | |
248 | */ | |
249 | if ((socklen_t) (tp - tmp) > size) | |
250 | { | |
251 | errno = ENOSPC; | |
252 | return NULL; | |
253 | } | |
254 | ||
255 | return strcpy (dst, tmp); | |
256 | } | |
257 | ||
258 | # endif | |
259 | ||
260 | #endif |