2 * Copyright (C) 2004 Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (C) 1996-2001 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 WITH
10 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
11 * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
12 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
13 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
14 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
15 * PERFORMANCE OF THIS SOFTWARE.
18 #if defined(LIBC_SCCS) && !defined(lint)
20 "$Id: inet_ntop.c,v 1.12.12.4 2004/08/28 06:25:21 marka Exp $";
21 #endif /* LIBC_SCCS and not lint */
30 #include <isc/print.h>
33 #define NS_IN6ADDRSZ 16
36 * WARNING: Don't even consider trying to compile this on a system where
37 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
40 static const char *inet_ntop4(const unsigned char *src, char *dst,
44 static const char *inet_ntop6(const unsigned char *src, char *dst,
49 * isc_net_ntop(af, src, dst, size)
50 * convert a network format address to presentation format.
52 * pointer to presentation format address (`dst'), or NULL (see errno).
57 isc_net_ntop(int af, const void *src, char *dst, size_t size)
61 return (inet_ntop4(src, dst, size));
64 return (inet_ntop6(src, dst, size));
74 * inet_ntop4(src, dst, size)
75 * format an IPv4 address
80 * (2) takes a unsigned char* not an in_addr as input
85 inet_ntop4(const unsigned char *src, char *dst, size_t size)
87 static const char *fmt = "%u.%u.%u.%u";
88 char tmp[sizeof("255.255.255.255")];
90 if ((size_t)sprintf(tmp, fmt, src[0], src[1], src[2], src[3]) >= size)
101 * isc_inet_ntop6(src, dst, size)
102 * convert IPv6 binary address into presentation (printable) format
108 inet_ntop6(const unsigned char *src, char *dst, size_t size)
111 * Note that int32_t and int16_t need only be "at least" large enough
112 * to contain a value of the specified size. On some systems, like
113 * Crays, there is no such thing as an integer variable with 16 bits.
114 * Keep this in mind if you think this function should have been coded
115 * to use pointer overlays. All the world's not a VAX.
117 char tmp[sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")], *tp;
118 struct { int base, len; } best, cur;
119 unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ];
124 * Copy the input (bytewise) array into a wordwise array.
125 * Find the longest run of 0x00's in src[] for :: shorthanding.
127 memset(words, '\0', sizeof(words));
128 for (i = 0; i < NS_IN6ADDRSZ; i++)
129 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
132 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
135 cur.base = i, cur.len = 1;
139 if (cur.base != -1) {
140 if (best.base == -1 || cur.len > best.len)
146 if (cur.base != -1) {
147 if (best.base == -1 || cur.len > best.len)
150 if (best.base != -1 && best.len < 2)
157 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
158 /* Are we inside the best run of 0x00's? */
159 if (best.base != -1 && i >= best.base &&
160 i < (best.base + best.len)) {
165 /* Are we following an initial run of 0x00s or any real hex? */
168 /* Is this address an encapsulated IPv4? */
169 if (i == 6 && best.base == 0 &&
170 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
171 if (!inet_ntop4(src+12, tp,
172 sizeof(tmp) - (tp - tmp)))
177 tp += sprintf(tp, "%x", words[i]);
179 /* Was it a trailing run of 0x00's? */
180 if (best.base != -1 && (best.base + best.len) ==
181 (NS_IN6ADDRSZ / NS_INT16SZ))
186 * Check for overflow, copy, and we're done.
188 if ((size_t)(tp - tmp) > size) {
195 #endif /* AF_INET6 */