2 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (c) 1996-1999 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 ISC DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
15 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18 #if defined(LIBC_SCCS) && !defined(lint)
19 static const char rcsid[] = "$Id: inet_ntop.c,v 1.3.18.2 2005/11/03 23:02:22 marka Exp $";
20 #endif /* LIBC_SCCS and not lint */
21 #include <sys/cdefs.h>
22 __FBSDID("$FreeBSD$");
24 #include "port_before.h"
26 #include <sys/param.h>
27 #include <sys/types.h>
28 #include <sys/socket.h>
30 #include <netinet/in.h>
31 #include <arpa/inet.h>
32 #include <arpa/nameser.h>
38 #include "port_after.h"
41 * WARNING: Don't even consider trying to compile this on a system where
42 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
45 static const char *inet_ntop4(const u_char *src, char *dst, socklen_t size);
46 static const char *inet_ntop6(const u_char *src, char *dst, socklen_t size);
49 * inet_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 inet_ntop(int af, const void * __restrict src, char * __restrict dst,
62 return (inet_ntop4(src, dst, size));
64 return (inet_ntop6(src, dst, size));
73 * inet_ntop4(src, dst, size)
74 * format an IPv4 address
79 * (2) takes a u_char* not an in_addr as input
84 inet_ntop4(const u_char *src, char *dst, socklen_t size)
86 static const char fmt[] = "%u.%u.%u.%u";
87 char tmp[sizeof "255.255.255.255"];
90 l = snprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]);
91 if (l <= 0 || (socklen_t) l >= size) {
95 strlcpy(dst, tmp, size);
100 * inet_ntop6(src, dst, size)
101 * convert IPv6 binary address into presentation (printable) format
106 inet_ntop6(const u_char *src, char *dst, socklen_t size)
109 * Note that int32_t and int16_t need only be "at least" large enough
110 * to contain a value of the specified size. On some systems, like
111 * Crays, there is no such thing as an integer variable with 16 bits.
112 * Keep this in mind if you think this function should have been coded
113 * to use pointer overlays. All the world's not a VAX.
115 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
116 struct { int base, len; } best, cur;
117 u_int words[NS_IN6ADDRSZ / NS_INT16SZ];
122 * Copy the input (bytewise) array into a wordwise array.
123 * Find the longest run of 0x00's in src[] for :: shorthanding.
125 memset(words, '\0', sizeof words);
126 for (i = 0; i < NS_IN6ADDRSZ; i++)
127 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 && (best.len == 6 ||
170 (best.len == 7 && words[7] != 0x0001) ||
171 (best.len == 5 && words[5] == 0xffff))) {
172 if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp))) {
179 tp += sprintf(tp, "%x", words[i]);
181 /* Was it a trailing run of 0x00's? */
182 if (best.base != -1 && (best.base + best.len) ==
183 (NS_IN6ADDRSZ / NS_INT16SZ))
188 * Check for overflow, copy, and we're done.
190 if ((socklen_t)(tp - tmp) > size) {
199 * Weak aliases for applications that use certain private entry points,
200 * and fail to include <arpa/inet.h>.
203 __weak_reference(__inet_ntop, inet_ntop);