1 /* inet_ntop.c -- convert IPv4 and IPv6 addresses from binary to text form
3 Copyright (C) 2005-2006, 2008-2023 Free Software Foundation, Inc.
5 This file is free software: you can redistribute it and/or modify
6 it under the terms of the GNU Lesser General Public License as
7 published by the Free Software Foundation; either version 2.1 of the
8 License, or (at your option) any later version.
10 This file is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public License
16 along with this program. If not, see <https://www.gnu.org/licenses/>. */
19 * Copyright (c) 1996-1999 by Internet Software Consortium.
21 * Permission to use, copy, modify, and distribute this software for any
22 * purpose with or without fee is hereby granted, provided that the above
23 * copyright notice and this permission notice appear in all copies.
25 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
26 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
27 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
28 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
29 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
30 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
31 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
38 #include <arpa/inet.h>
40 /* Use this to suppress gcc's "...may be used before initialized" warnings.
41 Beware: The Code argument must not contain commas. */
43 # if defined GCC_LINT || defined lint
44 # define IF_LINT(Code) Code
46 # define IF_LINT(Code) /* empty */
50 #if HAVE_DECL_INET_NTOP
55 rpl_inet_ntop (int af
, const void *restrict src
,
56 char *restrict dst
, socklen_t cnt
)
58 return inet_ntop (af
, src
, dst
, cnt
);
67 # define NS_IN6ADDRSZ 16
71 * WARNING: Don't even consider trying to compile this on a system where
72 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
74 typedef int verify_int_size
[4 <= sizeof (int) ? 1 : -1];
76 static const char *inet_ntop4 (const unsigned char *src
, char *dst
, socklen_t size
);
78 static const char *inet_ntop6 (const unsigned char *src
, char *dst
, socklen_t size
);
83 * inet_ntop(af, src, dst, size)
84 * convert a network format address to presentation format.
86 * pointer to presentation format address ('dst'), or NULL (see errno).
91 inet_ntop (int af
, const void *restrict src
,
92 char *restrict dst
, socklen_t cnt
)
98 return (inet_ntop4 (src
, dst
, cnt
));
103 return (inet_ntop6 (src
, dst
, cnt
));
107 errno
= EAFNOSUPPORT
;
114 * inet_ntop4(src, dst, size)
115 * format an IPv4 address
119 * (1) uses no statics
120 * (2) takes a u_char* not an in_addr as input
125 inet_ntop4 (const unsigned char *src
, char *dst
, socklen_t size
)
127 char tmp
[sizeof "255.255.255.255"];
130 len
= sprintf (tmp
, "%u.%u.%u.%u", src
[0], src
[1], src
[2], src
[3]);
140 return strcpy (dst
, tmp
);
146 * inet_ntop6(src, dst, size)
147 * convert IPv6 binary address into presentation (printable) format
152 inet_ntop6 (const unsigned char *src
, char *dst
, socklen_t size
)
155 * Note that int32_t and int16_t need only be "at least" large enough
156 * to contain a value of the specified size. On some systems, like
157 * Crays, there is no such thing as an integer variable with 16 bits.
158 * Keep this in mind if you think this function should have been coded
159 * to use pointer overlays. All the world's not a VAX.
161 char tmp
[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp
;
166 unsigned int words
[NS_IN6ADDRSZ
/ NS_INT16SZ
];
171 * Copy the input (bytewise) array into a wordwise array.
172 * Find the longest run of 0x00's in src[] for :: shorthanding.
174 memset (words
, '\0', sizeof words
);
175 for (i
= 0; i
< NS_IN6ADDRSZ
; i
+= 2)
176 words
[i
/ 2] = (src
[i
] << 8) | src
[i
+ 1];
179 IF_LINT(best
.len
= 0);
180 IF_LINT(cur
.len
= 0);
181 for (i
= 0; i
< (NS_IN6ADDRSZ
/ NS_INT16SZ
); i
++)
186 cur
.base
= i
, cur
.len
= 1;
194 if (best
.base
== -1 || cur
.len
> best
.len
)
202 if (best
.base
== -1 || cur
.len
> best
.len
)
205 if (best
.base
!= -1 && best
.len
< 2)
212 for (i
= 0; i
< (NS_IN6ADDRSZ
/ NS_INT16SZ
); i
++)
214 /* Are we inside the best run of 0x00's? */
215 if (best
.base
!= -1 && i
>= best
.base
&& i
< (best
.base
+ best
.len
))
221 /* Are we following an initial run of 0x00s or any real hex? */
224 /* Is this address an encapsulated IPv4? */
225 if (i
== 6 && best
.base
== 0 &&
226 (best
.len
== 6 || (best
.len
== 5 && words
[5] == 0xffff)))
228 if (!inet_ntop4 (src
+ 12, tp
, sizeof tmp
- (tp
- tmp
)))
234 int len
= sprintf (tp
, "%x", words
[i
]);
240 /* Was it a trailing run of 0x00's? */
241 if (best
.base
!= -1 && (best
.base
+ best
.len
) ==
242 (NS_IN6ADDRSZ
/ NS_INT16SZ
))
247 * Check for overflow, copy, and we're done.
249 if ((socklen_t
) (tp
- tmp
) > size
)
255 return strcpy (dst
, tmp
);