2 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (c) 1996-1999 by Internet Software Consortium.
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.
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.
18 #include "ares_setup.h"
20 #ifdef HAVE_NETINET_IN_H
21 # include <netinet/in.h>
23 #ifdef HAVE_ARPA_INET_H
24 # include <arpa/inet.h>
26 #ifdef HAVE_ARPA_NAMESER_H
27 # include <arpa/nameser.h>
31 #ifdef HAVE_ARPA_NAMESER_COMPAT_H
32 # include <arpa/nameser_compat.h>
36 #include "ares_ipv6.h"
37 #include "inet_ntop.h"
40 #ifndef HAVE_INET_NTOP
43 * WARNING: Don't even consider trying to compile this on a system where
44 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
47 static const char *inet_ntop4(const unsigned char *src, char *dst, size_t size);
48 static const char *inet_ntop6(const unsigned char *src, char *dst, size_t size);
51 * inet_ntop(af, src, dst, size)
52 * convert a network format address to presentation format.
54 * pointer to presentation format address (`dst'), or NULL (see errno).
56 * On Windows we store the error in the thread errno, not
57 * in the winsock error code. This is to avoid loosing the
58 * actual last winsock error. So use macro ERRNO to fetch the
59 * errno this funtion sets when returning NULL, not SOCKERRNO.
64 ares_inet_ntop(int af, const void *src, char *dst, size_t size)
68 return (inet_ntop4(src, dst, size));
70 return (inet_ntop6(src, dst, size));
72 SET_ERRNO(EAFNOSUPPORT);
79 * inet_ntop4(src, dst, size)
80 * format an IPv4 address
85 * (2) takes a unsigned char* not an in_addr as input
90 inet_ntop4(const unsigned char *src, char *dst, size_t size)
92 static const char fmt[] = "%u.%u.%u.%u";
93 char tmp[sizeof("255.255.255.255")];
95 if ((size_t)sprintf(tmp, fmt, src[0], src[1], src[2], src[3]) >= size) {
104 * inet_ntop6(src, dst, size)
105 * convert IPv6 binary address into presentation (printable) format
110 inet_ntop6(const unsigned char *src, char *dst, size_t size)
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.
119 char tmp[sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")];
121 struct { int base, len; } best, cur;
122 unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ];
127 * Copy the input (bytewise) array into a wordwise array.
128 * Find the longest run of 0x00's in src[] for :: shorthanding.
130 memset(words, '\0', sizeof(words));
131 for (i = 0; i < NS_IN6ADDRSZ; i++)
132 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
137 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
140 cur.base = i, cur.len = 1;
144 if (cur.base != -1) {
145 if (best.base == -1 || cur.len > best.len)
151 if (cur.base != -1) {
152 if (best.base == -1 || cur.len > best.len)
155 if (best.base != -1 && best.len < 2)
162 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
163 /* Are we inside the best run of 0x00's? */
164 if (best.base != -1 && i >= best.base &&
165 i < (best.base + best.len)) {
170 /* Are we following an initial run of 0x00s or any real hex? */
173 /* Is this address an encapsulated IPv4? */
174 if (i == 6 && best.base == 0 && (best.len == 6 ||
175 (best.len == 7 && words[7] != 0x0001) ||
176 (best.len == 5 && words[5] == 0xffff))) {
177 if (!inet_ntop4(src+12, tp, sizeof(tmp) - (tp - tmp)))
182 tp += sprintf(tp, "%x", words[i]);
184 /* Was it a trailing run of 0x00's? */
185 if (best.base != -1 && (best.base + best.len) ==
186 (NS_IN6ADDRSZ / NS_INT16SZ))
191 * Check for overflow, copy, and we're done.
193 if ((size_t)(tp - tmp) > size) {