xref: /openbsd-src/lib/libc/net/inet_neta.c (revision db5b349cf7aa19c2b6169fbb65597f2e741714ab)
1 /*	$OpenBSD: inet_neta.c,v 1.6 2005/03/25 13:24:12 otto Exp $	*/
2 
3 /*
4  * Copyright (c) 1996 by Internet Software Consortium.
5  *
6  * Permission to use, copy, modify, and distribute this software for any
7  * purpose with or without fee is hereby granted, provided that the above
8  * copyright notice and this permission notice appear in all copies.
9  *
10  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
11  * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
12  * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
13  * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
14  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
15  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
16  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
17  * SOFTWARE.
18  */
19 
20 #if defined(LIBC_SCCS) && !defined(lint)
21 static const char rcsid[] = "$OpenBSD: inet_neta.c,v 1.6 2005/03/25 13:24:12 otto Exp $";
22 #endif
23 
24 #include <sys/types.h>
25 #include <sys/socket.h>
26 #include <netinet/in.h>
27 #include <arpa/inet.h>
28 
29 #include <errno.h>
30 #include <stdio.h>
31 #include <string.h>
32 
33 /*
34  * char *
35  * inet_neta(src, dst, size)
36  *	format an in_addr_t network number into presentation format.
37  * return:
38  *	pointer to dst, or NULL if an error occurred (check errno).
39  * note:
40  *	format of ``src'' is as for inet_network().
41  * author:
42  *	Paul Vixie (ISC), July 1996
43  */
44 char *
45 inet_neta(in_addr_t src, char *dst, size_t size)
46 {
47 	char *odst = dst;
48 	char *ep;
49 	int advance;
50 
51 	if (src == 0x00000000) {
52 		if (size < sizeof "0.0.0.0")
53 			goto emsgsize;
54 		strlcpy(dst, "0.0.0.0", size);
55 		return dst;
56 	}
57 	ep = dst + size;
58 	if (ep <= dst)
59 		goto emsgsize;
60 	while (src & 0xffffffff) {
61 		u_char b = (src & 0xff000000) >> 24;
62 
63 		src <<= 8;
64 		if (b || src) {
65 			if (ep - dst < sizeof "255.")
66 				goto emsgsize;
67 			advance = snprintf(dst, ep - dst, "%u", b);
68 			if (advance <= 0 || advance >= ep - dst)
69 				goto emsgsize;
70 			dst += advance;
71 			if (src != 0L) {
72 				if (dst + 1 >= ep)
73 					goto emsgsize;
74 				*dst++ = '.';
75 				*dst = '\0';
76 			}
77 		}
78 	}
79 	return (odst);
80 
81  emsgsize:
82 	errno = EMSGSIZE;
83 	return (NULL);
84 }
85