1/*
2 * Copyright (c) 1996,1999 by Internet Software Consortium.
3 *
4 * Permission to use, copy, modify, and distribute this software for any
5 * purpose with or without fee is hereby granted, provided that the above
6 * copyright notice and this permission notice appear in all copies.
7 *
8 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
9 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
10 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
11 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
12 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
13 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
14 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
15 * SOFTWARE.
16 */
17
18#if defined(LIBC_SCCS) && !defined(lint)
19static const char rcsid[] = "$BINDId: inet_net_ntop.c,v 1.6 1999/01/08 19:23:42 vixie Exp $";
20#endif
21
22#include <sys/types.h>
23#include <sys/socket.h>
24#include <netinet/in.h>
25#include <arpa/inet.h>
26
27#include <errno.h>
28#include <stdio.h>
29#include <string.h>
30#include <stdlib.h>
31
32#ifdef SPRINTF_CHAR
33# define SPRINTF(x) strlen(sprintf/**/x)
34#else
35# define SPRINTF(x) ((size_t)sprintf x)
36#endif
37
38static char * inet_net_ntop_ipv4 (const u_char *src, int bits,
39 char *dst, size_t size) __THROW;
40
41/*
42 * char *
43 * inet_net_ntop(af, src, bits, dst, size)
44 * convert network number from network to presentation format.
45 * generates CIDR style result always.
46 * return:
47 * pointer to dst, or NULL if an error occurred (check errno).
48 * author:
49 * Paul Vixie (ISC), July 1996
50 */
51char *
52inet_net_ntop (int af, const void *src, int bits, char *dst, size_t size)
53{
54 switch (af) {
55 case AF_INET:
56 return (inet_net_ntop_ipv4(src, bits, dst, size));
57 default:
58 __set_errno (EAFNOSUPPORT);
59 return (NULL);
60 }
61}
62
63/*
64 * static char *
65 * inet_net_ntop_ipv4(src, bits, dst, size)
66 * convert IPv4 network number from network to presentation format.
67 * generates CIDR style result always.
68 * return:
69 * pointer to dst, or NULL if an error occurred (check errno).
70 * note:
71 * network byte order assumed. this means 192.5.5.240/28 has
72 * 0b11110000 in its fourth octet.
73 * author:
74 * Paul Vixie (ISC), July 1996
75 */
76static char *
77inet_net_ntop_ipv4 (const u_char *src, int bits, char *dst, size_t size)
78{
79 char *odst = dst;
80 char *t;
81 u_int m;
82 int b;
83
84 if (bits < 0 || bits > 32) {
85 __set_errno (EINVAL);
86 return (NULL);
87 }
88 if (bits == 0) {
89 if (size < sizeof "0")
90 goto emsgsize;
91 *dst++ = '0';
92 size--;
93 *dst = '\0';
94 }
95
96 /* Format whole octets. */
97 for (b = bits / 8; b > 0; b--) {
98 if (size < sizeof "255.")
99 goto emsgsize;
100 t = dst;
101 dst += SPRINTF((dst, "%u", *src++));
102 if (b > 1) {
103 *dst++ = '.';
104 *dst = '\0';
105 }
106 size -= (size_t)(dst - t);
107 }
108
109 /* Format partial octet. */
110 b = bits % 8;
111 if (b > 0) {
112 if (size < sizeof ".255")
113 goto emsgsize;
114 t = dst;
115 if (dst != odst)
116 *dst++ = '.';
117 m = ((1 << b) - 1) << (8 - b);
118 dst += SPRINTF((dst, "%u", *src & m));
119 size -= (size_t)(dst - t);
120 }
121
122 /* Format CIDR /width. */
123 if (size < sizeof "/32")
124 goto emsgsize;
125 dst += SPRINTF((dst, "/%u", bits));
126 return (odst);
127
128 emsgsize:
129 __set_errno (EMSGSIZE);
130 return (NULL);
131}
132