1 /* from NetBSD: inet_ntop.c,v 1.9 2000/01/22 22:19:16 mycroft 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
20 #define EAFNOSUPPORT 52
31 # define SPRINTF(x) strlen(sprintf/**/x)
33 # define SPRINTF(x) ((size_t)sprintf x)
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 *src
, char *dst
, size_t size
)
58 return (inet_ntop4(src
, dst
, size
));
61 return (inet_ntop6(src
, dst
, size
));
71 * inet_ntop4(src, dst, size)
72 * format an IPv4 address, more or less like inet_ntoa()
77 * (2) takes a u_char* not an in_addr as input
82 inet_ntop4(const u_char
*src
, char *dst
, size_t size
)
84 static const char fmt
[] = "%u.%u.%u.%u";
85 char tmp
[sizeof "255.255.255.255"];
87 if (SPRINTF((tmp
, fmt
, src
[0], src
[1], src
[2], src
[3])) > size
) {
97 * inet_ntop6(src, dst, size)
98 * convert IPv6 binary address into presentation (printable) format
103 inet_ntop6(const u_char
*src
, char *dst
, size_t size
)
106 * Note that int32_t and int16_t need only be "at least" large enough
107 * to contain a value of the specified size. On some systems, like
108 * Crays, there is no such thing as an integer variable with 16 bits.
109 * Keep this in mind if you think this function should have been coded
110 * to use pointer overlays. All the world's not a VAX.
112 char tmp
[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp
;
113 struct { int base
, len
; } best
, cur
;
114 u_int words
[IN6ADDRSZ
/ INT16SZ
];
119 * Copy the input (bytewise) array into a wordwise array.
120 * Find the longest run of 0x00's in src[] for :: shorthanding.
122 memset(words
, '\0', sizeof words
);
123 for (i
= 0; i
< IN6ADDRSZ
; i
++)
124 words
[i
/ 2] |= (src
[i
] << ((1 - (i
% 2)) << 3));
127 for (i
= 0; i
< (IN6ADDRSZ
/ INT16SZ
); i
++) {
130 cur
.base
= i
, cur
.len
= 1;
134 if (cur
.base
!= -1) {
135 if (best
.base
== -1 || cur
.len
> best
.len
)
141 if (cur
.base
!= -1) {
142 if (best
.base
== -1 || cur
.len
> best
.len
)
145 if (best
.base
!= -1 && best
.len
< 2)
152 for (i
= 0; i
< (IN6ADDRSZ
/ INT16SZ
); i
++) {
153 /* Are we inside the best run of 0x00's? */
154 if (best
.base
!= -1 && i
>= best
.base
&&
155 i
< (best
.base
+ best
.len
)) {
160 /* Are we following an initial run of 0x00s or any real hex? */
163 /* Is this address an encapsulated IPv4? */
164 if (i
== 6 && best
.base
== 0 &&
165 (best
.len
== 6 || (best
.len
== 5 && words
[5] == 0xffff))) {
166 if (!inet_ntop4(src
+12, tp
, sizeof tmp
- (tp
- tmp
)))
171 tp
+= SPRINTF((tp
, "%x", words
[i
]));
173 /* Was it a trailing run of 0x00's? */
174 if (best
.base
!= -1 && (best
.base
+ best
.len
) == (IN6ADDRSZ
/ INT16SZ
))
179 * Check for overflow, copy, and we're done.
181 if ((size_t)(tp
- tmp
) > size
) {