2 * Copyright (C) 2004, 2005, 2007, 2009 Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (C) 1996-2001 Internet Software Consortium.
5 * Permission to use, copy, modify, and/or 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.
20 #if defined(LIBC_SCCS) && !defined(lint)
22 "$Id: inet_ntop.c,v 1.21 2009/07/17 23:47:41 tbox Exp $";
23 #endif /* LIBC_SCCS and not lint */
32 #include <isc/print.h>
35 #define NS_IN6ADDRSZ 16
38 * WARNING: Don't even consider trying to compile this on a system where
39 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
42 static const char *inet_ntop4(const unsigned char *src, char *dst,
46 static const char *inet_ntop6(const unsigned char *src, char *dst,
49 const char *isc_net_ntop(int af, const void *src, char *dst, size_t size);
52 * isc_net_ntop(af, src, dst, size)
53 * convert a network format address to presentation format.
55 * pointer to presentation format address (`dst'), or NULL (see errno).
60 isc_net_ntop(int af, const void *src, char *dst, size_t size)
64 return (inet_ntop4(src, dst, size));
67 return (inet_ntop6(src, dst, size));
77 * inet_ntop4(src, dst, size)
78 * format an IPv4 address
84 * (2) takes a unsigned char* not an in_addr as input
89 inet_ntop4(const unsigned char *src, char *dst, size_t size)
91 static const char *fmt = "%u.%u.%u.%u";
92 char tmp[sizeof("255.255.255.255")];
95 len = snprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]);
96 if (len < 0 || (size_t)len >= size)
101 memcpy(dst, tmp, 1 + len);
107 * isc_inet_ntop6(src, dst, size)
108 * convert IPv6 binary address into presentation (printable) format
114 inet_ntop6(const unsigned char *src, char *dst, size_t size)
117 * Note that int32_t and int16_t need only be "at least" large enough
118 * to contain a value of the specified size. On some systems, like
119 * Crays, there is no such thing as an integer variable with 16 bits.
120 * Keep this in mind if you think this function should have been coded
121 * to use pointer overlays. All the world's not a VAX.
123 char tmp[sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")], *tp;
124 struct { int base, len; } best, cur;
125 unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ];
130 * Copy the input (bytewise) array into a wordwise array.
131 * Find the longest run of 0x00's in src[] for :: shorthanding.
133 memset(words, '\0', sizeof(words));
134 for (i = 0; i < NS_IN6ADDRSZ; i++)
135 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
138 best.len = cur.len = 0;
139 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
142 cur.base = i, cur.len = 1;
146 if (cur.base != -1) {
147 if (best.base == -1 || cur.len > best.len)
153 if (cur.base != -1) {
154 if (best.base == -1 || cur.len > best.len)
157 if (best.base != -1 && best.len < 2)
164 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
165 /* Are we inside the best run of 0x00's? */
166 if (best.base != -1 && i >= best.base &&
167 i < (best.base + best.len)) {
172 /* Are we following an initial run of 0x00s or any real hex? */
175 /* Is this address an encapsulated IPv4? */
176 if (i == 6 && best.base == 0 && (best.len == 6 ||
177 (best.len == 7 && words[7] != 0x0001) ||
178 (best.len == 5 && words[5] == 0xffff))) {
179 if (!inet_ntop4(src+12, tp,
180 sizeof(tmp) - (tp - tmp)))
185 tp += snprintf(tp, sizeof(tmp) - (tp - tmp), "%x", words[i]);
187 /* Was it a trailing run of 0x00's? */
188 if (best.base != -1 && (best.base + best.len) ==
189 (NS_IN6ADDRSZ / NS_INT16SZ))
194 * Check for overflow, copy, and we're done.
196 if ((size_t)(tp - tmp) > size) {
200 memcpy(dst, tmp, (size_t)(tp - tmp));
203 #endif /* AF_INET6 */