1 /* $OpenBSD: inet_ntop.c,v 1.1 1997/03/13 19:07:32 downsj 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
21 #ifndef HAVE_INET_NTOP
23 #if defined(LIBC_SCCS) && !defined(lint)
25 static char rcsid[] = "$From: inet_ntop.c,v 8.7 1996/08/05 08:41:18 vixie Exp $";
27 static char rcsid[] = "$OpenBSD: inet_ntop.c,v 1.1 1997/03/13 19:07:32 downsj Exp $";
29 #endif /* LIBC_SCCS and not lint */
31 #include <sys/param.h>
32 #include <sys/types.h>
33 #include <sys/socket.h>
34 #include <netinet/in.h>
35 #include <arpa/inet.h>
37 #include <arpa/nameser.h>
44 #define IN6ADDRSZ 16 /* IPv6 T_AAAA */
48 #define INT16SZ 2 /* for systems without 16-bit ints */
52 * WARNING: Don't even consider trying to compile this on a system where
53 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
56 static const char *inet_ntop4 (const u_char *src, char *dst, size_t size);
58 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));
81 return (inet_ntop6(src, dst, size));
91 * inet_ntop4(src, dst, size)
92 * format an IPv4 address, more or less like inet_ntoa()
97 * (2) takes a u_char* not an in_addr as input
102 inet_ntop4(src, dst, size)
107 static const char fmt[] = "%u.%u.%u.%u";
108 char tmp[sizeof "255.255.255.255"];
110 if (sprintf(tmp, fmt, src[0], src[1], src[2], src[3]) > size) {
119 * inet_ntop6(src, dst, size)
120 * convert IPv6 binary address into presentation (printable) format
126 inet_ntop6(src, dst, size)
132 * Note that int32_t and int16_t need only be "at least" large enough
133 * to contain a value of the specified size. On some systems, like
134 * Crays, there is no such thing as an integer variable with 16 bits.
135 * Keep this in mind if you think this function should have been coded
136 * to use pointer overlays. All the world's not a VAX.
138 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
139 struct { int base, len; } best, cur;
140 u_int words[IN6ADDRSZ / INT16SZ];
145 * Copy the input (bytewise) array into a wordwise array.
146 * Find the longest run of 0x00's in src[] for :: shorthanding.
148 memset(words, '\0', sizeof words);
149 for (i = 0; i < IN6ADDRSZ; i++)
150 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
153 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) {
156 cur.base = i, cur.len = 1;
160 if (cur.base != -1) {
161 if (best.base == -1 || cur.len > best.len)
167 if (cur.base != -1) {
168 if (best.base == -1 || cur.len > best.len)
171 if (best.base != -1 && best.len < 2)
178 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) {
179 /* Are we inside the best run of 0x00's? */
180 if (best.base != -1 && i >= best.base &&
181 i < (best.base + best.len)) {
186 /* Are we following an initial run of 0x00s or any real hex? */
189 /* Is this address an encapsulated IPv4? */
190 if (i == 6 && best.base == 0 &&
191 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
192 if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
197 tp += sprintf(tp, "%x", words[i]);
199 /* Was it a trailing run of 0x00's? */
200 if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ))
205 * Check for overflow, copy, and we're done.
207 if ((size_t)(tp - tmp) > size) {
214 #endif /* AF_INET6 */
216 #endif /* !HAVE_INET_NTOP */