1 /* $OpenBSD: inet_ntop.c,v 1.5 2002/08/23 16:27:31 itojun Exp $ */
3 /* Copyright (c) 1996 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 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
18 * $From: inet_ntop.c,v 8.7 1996/08/05 08:41:18 vixie Exp $";
19 * $OpenBSD: inet_ntop.c,v 1.5 2002/08/23 16:27:31 itojun Exp $
24 #ifndef HAVE_INET_NTOP
26 #include <sys/param.h>
27 #include <sys/types.h>
28 #include <sys/socket.h>
29 #include "openbsd-compat/fake-socket.h"
30 #include <netinet/in.h>
31 #include <arpa/inet.h>
33 #include <arpa/nameser.h>
40 #define IN6ADDRSZ 16 /* IPv6 T_AAAA */
44 #define INT16SZ 2 /* for systems without 16-bit ints */
48 * WARNING: Don't even consider trying to compile this on a system where
49 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
52 static const char *inet_ntop4(const u_char *src, char *dst, size_t size);
53 static const char *inet_ntop6(const u_char *src, char *dst, size_t size);
56 * inet_ntop(af, src, dst, size)
57 * convert a network format address to presentation format.
59 * pointer to presentation format address (`dst'), or NULL (see errno).
64 inet_ntop(af, src, dst, size)
72 return (inet_ntop4(src, dst, size));
74 return (inet_ntop6(src, dst, size));
83 * inet_ntop4(src, dst, size)
84 * format an IPv4 address, more or less like inet_ntoa()
89 * (2) takes a u_char* not an in_addr as input
94 inet_ntop4(src, dst, size)
99 static const char fmt[] = "%u.%u.%u.%u";
100 char tmp[sizeof "255.255.255.255"];
103 l = snprintf(tmp, size, fmt, src[0], src[1], src[2], src[3]);
104 if (l <= 0 || l >= size) {
108 strlcpy(dst, tmp, size);
113 * inet_ntop6(src, dst, size)
114 * convert IPv6 binary address into presentation (printable) format
119 inet_ntop6(src, dst, size)
125 * Note that int32_t and int16_t need only be "at least" large enough
126 * to contain a value of the specified size. On some systems, like
127 * Crays, there is no such thing as an integer variable with 16 bits.
128 * Keep this in mind if you think this function should have been coded
129 * to use pointer overlays. All the world's not a VAX.
131 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"];
133 struct { int base, len; } best, cur;
134 u_int words[IN6ADDRSZ / INT16SZ];
140 * Copy the input (bytewise) array into a wordwise array.
141 * Find the longest run of 0x00's in src[] for :: shorthanding.
143 memset(words, '\0', sizeof words);
144 for (i = 0; i < IN6ADDRSZ; i++)
145 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
148 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) {
151 cur.base = i, cur.len = 1;
155 if (cur.base != -1) {
156 if (best.base == -1 || cur.len > best.len)
162 if (cur.base != -1) {
163 if (best.base == -1 || cur.len > best.len)
166 if (best.base != -1 && best.len < 2)
173 ep = tmp + sizeof(tmp);
174 for (i = 0; i < (IN6ADDRSZ / INT16SZ) && tp < ep; i++) {
175 /* Are we inside the best run of 0x00's? */
176 if (best.base != -1 && i >= best.base &&
177 i < (best.base + best.len)) {
178 if (i == best.base) {
185 /* Are we following an initial run of 0x00s or any real hex? */
191 /* Is this address an encapsulated IPv4? */
192 if (i == 6 && best.base == 0 &&
193 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
194 if (!inet_ntop4(src+12, tp, (size_t)(ep - tp)))
199 advance = snprintf(tp, ep - tp, "%x", words[i]);
200 if (advance <= 0 || advance >= ep - tp)
204 /* Was it a trailing run of 0x00's? */
205 if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ)) {
215 * Check for overflow, copy, and we're done.
217 if ((size_t)(tp - tmp) > size) {
221 strlcpy(dst, tmp, size);
225 #endif /* !HAVE_INET_NTOP */