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 1.5 2005/11/03 22:59:52 marka Exp $";
20 #endif /* LIBC_SCCS and not lint */
22 #include "port_before.h"
24 #include <sys/param.h>
25 #include <sys/types.h>
26 #include <sys/socket.h>
28 #include <netinet/in.h>
29 #include "arpa/inet.h"
30 #include <arpa/nameser.h>
36 #include "port_after.h"
39 # define SPRINTF(x) strlen(sprintf/**/x)
41 # define SPRINTF(x) ((size_t)sprintf x)
45 * WARNING: Don't even consider trying to compile this on a system where
46 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
49 static const char *inet_ntop4
__P((const u_char
*src
, char *dst
, size_t size
));
50 static const char *inet_ntop6
__P((const u_char
*src
, char *dst
, size_t size
));
53 * inet_ntop(af, src, dst, size)
54 * convert a network format address to presentation format.
56 * pointer to presentation format address (`dst'), or NULL (see errno).
61 inet_ntop(af
, src
, dst
, size
)
69 return (inet_ntop4(src
, dst
, size
));
71 return (inet_ntop6(src
, dst
, size
));
80 * inet_ntop4(src, dst, size)
81 * format an IPv4 address
86 * (2) takes a u_char* not an in_addr as input
91 inet_ntop4(src
, dst
, size
)
96 static const char fmt
[] = "%u.%u.%u.%u";
97 char tmp
[sizeof "255.255.255.255"];
99 if (SPRINTF((tmp
, fmt
, src
[0], src
[1], src
[2], src
[3])) >= size
) {
108 * inet_ntop6(src, dst, size)
109 * convert IPv6 binary address into presentation (printable) format
114 inet_ntop6(src
, dst
, size
)
120 * Note that int32_t and int16_t need only be "at least" large enough
121 * to contain a value of the specified size. On some systems, like
122 * Crays, there is no such thing as an integer variable with 16 bits.
123 * Keep this in mind if you think this function should have been coded
124 * to use pointer overlays. All the world's not a VAX.
126 char tmp
[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp
;
127 struct { int base
, len
; } best
, cur
;
128 u_int words
[NS_IN6ADDRSZ
/ NS_INT16SZ
];
133 * Copy the input (bytewise) array into a wordwise array.
134 * Find the longest run of 0x00's in src[] for :: shorthanding.
136 memset(words
, '\0', sizeof words
);
137 for (i
= 0; i
< NS_IN6ADDRSZ
; i
++)
138 words
[i
/ 2] |= (src
[i
] << ((1 - (i
% 2)) << 3));
143 for (i
= 0; i
< (NS_IN6ADDRSZ
/ NS_INT16SZ
); i
++) {
146 cur
.base
= i
, cur
.len
= 1;
150 if (cur
.base
!= -1) {
151 if (best
.base
== -1 || cur
.len
> best
.len
)
157 if (cur
.base
!= -1) {
158 if (best
.base
== -1 || cur
.len
> best
.len
)
161 if (best
.base
!= -1 && best
.len
< 2)
168 for (i
= 0; i
< (NS_IN6ADDRSZ
/ NS_INT16SZ
); i
++) {
169 /* Are we inside the best run of 0x00's? */
170 if (best
.base
!= -1 && i
>= best
.base
&&
171 i
< (best
.base
+ best
.len
)) {
176 /* Are we following an initial run of 0x00s or any real hex? */
179 /* Is this address an encapsulated IPv4? */
180 if (i
== 6 && best
.base
== 0 && (best
.len
== 6 ||
181 (best
.len
== 7 && words
[7] != 0x0001) ||
182 (best
.len
== 5 && words
[5] == 0xffff))) {
183 if (!inet_ntop4(src
+12, tp
, sizeof tmp
- (tp
- tmp
)))
188 tp
+= SPRINTF((tp
, "%x", words
[i
]));
190 /* Was it a trailing run of 0x00's? */
191 if (best
.base
!= -1 && (best
.base
+ best
.len
) ==
192 (NS_IN6ADDRSZ
/ NS_INT16SZ
))
197 * Check for overflow, copy, and we're done.
199 if ((size_t)(tp
- tmp
) > size
) {
209 * Weak aliases for applications that use certain private entry points,
210 * and fail to include <arpa/inet.h>.
213 __weak_reference(__inet_ntop
, inet_ntop
);