1 /* OPENBSD ORIGINAL: lib/libc/net/inet_ntop.c */
3 /* $OpenBSD: inet_ntop.c,v 1.5 2002/08/23 16:27:31 itojun Exp $ */
5 /* Copyright (c) 1996 by Internet Software Consortium.
7 * Permission to use, copy, modify, and distribute this software for any
8 * purpose with or without fee is hereby granted, provided that the above
9 * copyright notice and this permission notice appear in all copies.
11 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
12 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
13 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
14 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
15 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
16 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
17 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
23 #ifndef HAVE_INET_NTOP
25 #if defined(LIBC_SCCS) && !defined(lint)
27 static char rcsid[] = "$From: inet_ntop.c,v 8.7 1996/08/05 08:41:18 vixie Exp $";
29 static char rcsid[] = "$OpenBSD: inet_ntop.c,v 1.5 2002/08/23 16:27:31 itojun Exp $";
31 #endif /* LIBC_SCCS and not lint */
33 #include <sys/param.h>
34 #include <sys/types.h>
35 #include <sys/socket.h>
36 #include <netinet/in.h>
37 #include <arpa/inet.h>
39 #include <arpa/nameser.h>
46 #define IN6ADDRSZ 16 /* IPv6 T_AAAA */
50 #define INT16SZ 2 /* for systems without 16-bit ints */
54 * WARNING: Don't even consider trying to compile this on a system where
55 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
58 static const char *inet_ntop4(const u_char *src, char *dst, size_t size);
59 static const char *inet_ntop6(const u_char *src, char *dst, size_t size);
62 * inet_ntop(af, src, dst, size)
63 * convert a network format address to presentation format.
65 * pointer to presentation format address (`dst'), or NULL (see errno).
70 inet_ntop(af, src, dst, size)
78 return (inet_ntop4(src, dst, size));
80 return (inet_ntop6(src, dst, size));
89 * inet_ntop4(src, dst, size)
90 * format an IPv4 address, more or less like inet_ntoa()
95 * (2) takes a u_char* not an in_addr as input
100 inet_ntop4(src, dst, size)
105 static const char fmt[] = "%u.%u.%u.%u";
106 char tmp[sizeof "255.255.255.255"];
109 l = snprintf(tmp, size, fmt, src[0], src[1], src[2], src[3]);
110 if (l <= 0 || l >= size) {
114 strlcpy(dst, tmp, size);
119 * inet_ntop6(src, dst, size)
120 * convert IPv6 binary address into presentation (printable) format
125 inet_ntop6(src, dst, size)
131 * Note that int32_t and int16_t need only be "at least" large enough
132 * to contain a value of the specified size. On some systems, like
133 * Crays, there is no such thing as an integer variable with 16 bits.
134 * Keep this in mind if you think this function should have been coded
135 * to use pointer overlays. All the world's not a VAX.
137 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"];
139 struct { int base, len; } best, cur;
140 u_int words[IN6ADDRSZ / INT16SZ];
146 * Copy the input (bytewise) array into a wordwise array.
147 * Find the longest run of 0x00's in src[] for :: shorthanding.
149 memset(words, '\0', sizeof words);
150 for (i = 0; i < IN6ADDRSZ; i++)
151 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
154 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) {
157 cur.base = i, cur.len = 1;
161 if (cur.base != -1) {
162 if (best.base == -1 || cur.len > best.len)
168 if (cur.base != -1) {
169 if (best.base == -1 || cur.len > best.len)
172 if (best.base != -1 && best.len < 2)
179 ep = tmp + sizeof(tmp);
180 for (i = 0; i < (IN6ADDRSZ / INT16SZ) && tp < ep; i++) {
181 /* Are we inside the best run of 0x00's? */
182 if (best.base != -1 && i >= best.base &&
183 i < (best.base + best.len)) {
184 if (i == best.base) {
191 /* Are we following an initial run of 0x00s or any real hex? */
197 /* Is this address an encapsulated IPv4? */
198 if (i == 6 && best.base == 0 &&
199 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
200 if (!inet_ntop4(src+12, tp, (size_t)(ep - tp)))
205 advance = snprintf(tp, ep - tp, "%x", words[i]);
206 if (advance <= 0 || advance >= ep - tp)
210 /* Was it a trailing run of 0x00's? */
211 if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ)) {
221 * Check for overflow, copy, and we're done.
223 if ((size_t)(tp - tmp) > size) {
227 strlcpy(dst, tmp, size);
231 #endif /* !HAVE_INET_NTOP */