1 /* $OpenBSD: inet_ntop.c,v 1.8 2008/12/09 19:38:38 otto 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
19 /* OPENBSD ORIGINAL: lib/libc/net/inet_ntop.c */
23 #ifndef HAVE_INET_NTOP
25 #include <sys/param.h>
26 #include <sys/types.h>
27 #include <sys/socket.h>
28 #include <netinet/in.h>
29 #include <arpa/inet.h>
30 #include <arpa/nameser.h>
36 #define IN6ADDRSZ 16 /* IPv6 T_AAAA */
40 #define INT16SZ 2 /* for systems without 16-bit ints */
44 * WARNING: Don't even consider trying to compile this on a system where
45 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
48 static const char *inet_ntop4(const u_char *src, char *dst, size_t size);
49 static const char *inet_ntop6(const u_char *src, char *dst, size_t size);
52 * inet_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 inet_ntop(int af, const void *src, char *dst, socklen_t size)
64 return (inet_ntop4(src, dst, (size_t)size));
66 return (inet_ntop6(src, dst, (size_t)size));
75 * inet_ntop4(src, dst, size)
76 * format an IPv4 address, more or less like inet_ntoa()
81 * (2) takes a u_char* not an in_addr as input
86 inet_ntop4(const u_char *src, char *dst, size_t size)
88 static const char fmt[] = "%u.%u.%u.%u";
89 char tmp[sizeof "255.255.255.255"];
92 l = snprintf(tmp, size, fmt, src[0], src[1], src[2], src[3]);
93 if (l <= 0 || l >= size) {
97 strlcpy(dst, tmp, size);
102 * inet_ntop6(src, dst, size)
103 * convert IPv6 binary address into presentation (printable) format
108 inet_ntop6(const u_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"];
119 struct { int base, len; } best, cur;
120 u_int words[IN6ADDRSZ / INT16SZ];
126 * Copy the input (bytewise) array into a wordwise array.
127 * Find the longest run of 0x00's in src[] for :: shorthanding.
129 memset(words, '\0', sizeof words);
130 for (i = 0; i < IN6ADDRSZ; i++)
131 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
134 for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++) {
137 cur.base = i, cur.len = 1;
141 if (cur.base != -1) {
142 if (best.base == -1 || cur.len > best.len)
148 if (cur.base != -1) {
149 if (best.base == -1 || cur.len > best.len)
152 if (best.base != -1 && best.len < 2)
159 ep = tmp + sizeof(tmp);
160 for (i = 0; i < (IN6ADDRSZ / INT16SZ) && tp < ep; i++) {
161 /* Are we inside the best run of 0x00's? */
162 if (best.base != -1 && i >= best.base &&
163 i < (best.base + best.len)) {
164 if (i == best.base) {
171 /* Are we following an initial run of 0x00s or any real hex? */
177 /* Is this address an encapsulated IPv4? */
178 if (i == 6 && best.base == 0 &&
179 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
180 if (!inet_ntop4(src+12, tp, (size_t)(ep - tp)))
185 advance = snprintf(tp, ep - tp, "%x", words[i]);
186 if (advance <= 0 || advance >= ep - tp)
190 /* Was it a trailing run of 0x00's? */
191 if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ)) {
201 * Check for overflow, copy, and we're done.
203 if ((size_t)(tp - tmp) > size) {
207 strlcpy(dst, tmp, size);
211 #endif /* !HAVE_INET_NTOP */