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.
17 * $Id: inet_ntop.c,v 1.5 2005/11/03 22:59:52 marka Exp $
20 #include "port_before.h"
22 #include <sys/param.h>
23 #include <sys/types.h>
24 #include <sys/socket.h>
26 #include <netinet/in.h>
27 #include "arpa/inet.h"
28 #include <arpa/nameser.h>
34 #include "port_after.h"
37 * WARNING: Don't even consider trying to compile this on a system where
38 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
41 static const char *inet_ntop4(const u_char *src, char *dst, size_t size);
42 static const char *inet_ntop6(const u_char *src, char *dst, size_t size);
45 * inet_ntop(af, src, dst, size)
46 * convert a network format address to presentation format.
48 * pointer to presentation format address (`dst'), or NULL (see errno).
53 inet_ntop(int af, const void * __restrict src, char * __restrict dst,
58 return (inet_ntop4(src, dst, size));
60 return (inet_ntop6(src, dst, size));
69 * inet_ntop4(src, dst, size)
70 * format an IPv4 address
75 * (2) takes a u_char* not an in_addr as input
80 inet_ntop4(const u_char *src, char *dst, size_t size)
82 static const char fmt[] = "%u.%u.%u.%u";
83 char tmp[sizeof "255.255.255.255"];
86 l = snprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]);
87 if (l <= 0 || (socklen_t)l >= size) {
91 strlcpy(dst, tmp, size);
96 * inet_ntop6(src, dst, size)
97 * convert IPv6 binary address into presentation (printable) format
102 inet_ntop6(const u_char *src, char *dst, size_t size)
105 * Note that int32_t and int16_t need only be "at least" large enough
106 * to contain a value of the specified size. On some systems, like
107 * Crays, there is no such thing as an integer variable with 16 bits.
108 * Keep this in mind if you think this function should have been coded
109 * to use pointer overlays. All the world's not a VAX.
111 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
112 struct { int base, len; } best, cur;
113 u_int words[NS_IN6ADDRSZ / NS_INT16SZ];
118 * Copy the input (bytewise) array into a wordwise array.
119 * Find the longest run of 0x00's in src[] for :: shorthanding.
121 memset(words, '\0', sizeof words);
122 for (i = 0; i < NS_IN6ADDRSZ; i++)
123 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
128 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
131 cur.base = i, cur.len = 1;
135 if (cur.base != -1) {
136 if (best.base == -1 || cur.len > best.len)
142 if (cur.base != -1) {
143 if (best.base == -1 || cur.len > best.len)
146 if (best.base != -1 && best.len < 2)
153 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
154 /* Are we inside the best run of 0x00's? */
155 if (best.base != -1 && i >= best.base &&
156 i < (best.base + best.len)) {
161 /* Are we following an initial run of 0x00s or any real hex? */
164 /* Is this address an encapsulated IPv4? */
165 if (i == 6 && best.base == 0 && (best.len == 6 ||
166 (best.len == 7 && words[7] != 0x0001) ||
167 (best.len == 5 && words[5] == 0xffff))) {
168 if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp))) {
175 tp += sprintf(tp, "%x", words[i]);
177 /* Was it a trailing run of 0x00's? */
178 if (best.base != -1 && (best.base + best.len) ==
179 (NS_IN6ADDRSZ / NS_INT16SZ))
184 * Check for overflow, copy, and we're done.
186 if ((socklen_t)(tp - tmp) > size) {
195 * Weak aliases for applications that use certain private entry points,
196 * and fail to include <arpa/inet.h>.
199 __weak_reference(__inet_ntop, inet_ntop);