1 /*
2 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (c) 1996-1999 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 ISC DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
15 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18 #include "ares_setup.h"
19
20 #ifdef HAVE_SYS_SOCKET_H
21 # include <sys/socket.h>
22 #endif
23 #ifdef HAVE_NETINET_IN_H
24 # include <netinet/in.h>
25 #endif
26 #ifdef HAVE_ARPA_INET_H
27 # include <arpa/inet.h>
28 #endif
29 #ifdef HAVE_ARPA_NAMESER_H
30 # include <arpa/nameser.h>
31 #else
32 # include "nameser.h"
33 #endif
34 #ifdef HAVE_ARPA_NAMESER_COMPAT_H
35 # include <arpa/nameser_compat.h>
36 #endif
37
38 #include <ctype.h>
39 #include <stdio.h>
40 #include <string.h>
41 #include <stdlib.h>
42
43 #include "ares.h"
44 #include "ares_ipv6.h"
45 #include "inet_ntop.h"
46
47
48 #ifndef HAVE_INET_NTOP
49
50 /*
51 * WARNING: Don't even consider trying to compile this on a system where
52 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
53 */
54
55 static const char *inet_ntop4(const unsigned char *src, char *dst, size_t size);
56 static const char *inet_ntop6(const unsigned char *src, char *dst, size_t size);
57
58 /* char *
59 * inet_ntop(af, src, dst, size)
60 * convert a network format address to presentation format.
61 * return:
62 * pointer to presentation format address (`dst'), or NULL (see errno).
63 * note:
64 * On Windows we store the error in the thread errno, not
65 * in the winsock error code. This is to avoid loosing the
66 * actual last winsock error. So use macro ERRNO to fetch the
67 * errno this funtion sets when returning NULL, not SOCKERRNO.
68 * author:
69 * Paul Vixie, 1996.
70 */
71 const char *
ares_inet_ntop(int af,const void * src,char * dst,size_t size)72 ares_inet_ntop(int af, const void *src, char *dst, size_t size)
73 {
74 switch (af) {
75 case AF_INET:
76 return (inet_ntop4(src, dst, size));
77 case AF_INET6:
78 return (inet_ntop6(src, dst, size));
79 default:
80 SET_ERRNO(EAFNOSUPPORT);
81 return (NULL);
82 }
83 /* NOTREACHED */
84 }
85
86 /* const char *
87 * inet_ntop4(src, dst, size)
88 * format an IPv4 address
89 * return:
90 * `dst' (as a const)
91 * notes:
92 * (1) uses no statics
93 * (2) takes a unsigned char* not an in_addr as input
94 * author:
95 * Paul Vixie, 1996.
96 */
97 static const char *
inet_ntop4(const unsigned char * src,char * dst,size_t size)98 inet_ntop4(const unsigned char *src, char *dst, size_t size)
99 {
100 static const char fmt[] = "%u.%u.%u.%u";
101 char tmp[sizeof("255.255.255.255")];
102
103 if ((size_t)sprintf(tmp, fmt, src[0], src[1], src[2], src[3]) >= size) {
104 SET_ERRNO(ENOSPC);
105 return (NULL);
106 }
107 strcpy(dst, tmp);
108 return (dst);
109 }
110
111 /* const char *
112 * inet_ntop6(src, dst, size)
113 * convert IPv6 binary address into presentation (printable) format
114 * author:
115 * Paul Vixie, 1996.
116 */
117 static const char *
inet_ntop6(const unsigned char * src,char * dst,size_t size)118 inet_ntop6(const unsigned char *src, char *dst, size_t size)
119 {
120 /*
121 * Note that int32_t and int16_t need only be "at least" large enough
122 * to contain a value of the specified size. On some systems, like
123 * Crays, there is no such thing as an integer variable with 16 bits.
124 * Keep this in mind if you think this function should have been coded
125 * to use pointer overlays. All the world's not a VAX.
126 */
127 char tmp[sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")];
128 char *tp;
129 struct { int base, len; } best, cur;
130 unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ];
131 int i;
132
133 /*
134 * Preprocess:
135 * Copy the input (bytewise) array into a wordwise array.
136 * Find the longest run of 0x00's in src[] for :: shorthanding.
137 */
138 memset(words, '\0', sizeof(words));
139 for (i = 0; i < NS_IN6ADDRSZ; i++)
140 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
141 best.base = -1;
142 best.len = 0;
143 cur.base = -1;
144 cur.len = 0;
145 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
146 if (words[i] == 0) {
147 if (cur.base == -1)
148 cur.base = i, cur.len = 1;
149 else
150 cur.len++;
151 } else {
152 if (cur.base != -1) {
153 if (best.base == -1 || cur.len > best.len)
154 best = cur;
155 cur.base = -1;
156 }
157 }
158 }
159 if (cur.base != -1) {
160 if (best.base == -1 || cur.len > best.len)
161 best = cur;
162 }
163 if (best.base != -1 && best.len < 2)
164 best.base = -1;
165
166 /*
167 * Format the result.
168 */
169 tp = tmp;
170 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
171 /* Are we inside the best run of 0x00's? */
172 if (best.base != -1 && i >= best.base &&
173 i < (best.base + best.len)) {
174 if (i == best.base)
175 *tp++ = ':';
176 continue;
177 }
178 /* Are we following an initial run of 0x00s or any real hex? */
179 if (i != 0)
180 *tp++ = ':';
181 /* Is this address an encapsulated IPv4? */
182 if (i == 6 && best.base == 0 && (best.len == 6 ||
183 (best.len == 7 && words[7] != 0x0001) ||
184 (best.len == 5 && words[5] == 0xffff))) {
185 if (!inet_ntop4(src+12, tp, sizeof(tmp) - (tp - tmp)))
186 return (NULL);
187 tp += strlen(tp);
188 break;
189 }
190 tp += sprintf(tp, "%x", words[i]);
191 }
192 /* Was it a trailing run of 0x00's? */
193 if (best.base != -1 && (best.base + best.len) ==
194 (NS_IN6ADDRSZ / NS_INT16SZ))
195 *tp++ = ':';
196 *tp++ = '\0';
197
198 /*
199 * Check for overflow, copy, and we're done.
200 */
201 if ((size_t)(tp - tmp) > size) {
202 SET_ERRNO(ENOSPC);
203 return (NULL);
204 }
205 strcpy(dst, tmp);
206 return (dst);
207 }
208 #endif
209