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#include <sys/cdefs.h>
19#if defined(LIBC_SCCS) && !defined(lint)
20#ifdef notdef
21static const char rcsid[] = "Id: inet_net_ntop.c,v 1.1.2.1 2002/08/02 02:17:21 marka Exp ";
22#else
23__RCSID("$NetBSD: inet_net_ntop.c,v 1.1 2004/05/20 23:13:02 christos Exp $");
24#endif
25#endif
26
27#include "port_before.h"
28
29#include "namespace.h"
30#include <sys/types.h>
31#include <sys/socket.h>
32#include <netinet/in.h>
33#include <arpa/inet.h>
34
35#include <errno.h>
36#include <stdio.h>
37#include <string.h>
38#include <stdlib.h>
39
40#include "port_after.h"
41
42#ifdef __weak_alias
43__weak_alias(inet_net_ntop,_inet_net_ntop)
44#endif
45
46#ifdef SPRINTF_CHAR
47# define SPRINTF(x) strlen(sprintf/**/x)
48#else
49# define SPRINTF(x) sprintf x
50#endif
51
52static char *	inet_net_ntop_ipv4 __P((const u_char *src, int bits,
53					char *dst, size_t size));
54static char *	inet_net_ntop_ipv6 __P((const u_char *src, int bits,
55					char *dst, size_t size));
56
57/*
58 * char *
59 * inet_net_ntop(af, src, bits, dst, size)
60 *	convert network number from network to presentation format.
61 *	generates CIDR style result always.
62 * return:
63 *	pointer to dst, or NULL if an error occurred (check errno).
64 * author:
65 *	Paul Vixie (ISC), July 1996
66 */
67char *
68inet_net_ntop(af, src, bits, dst, size)
69	int af;
70	const void *src;
71	int bits;
72	char *dst;
73	size_t size;
74{
75	switch (af) {
76	case AF_INET:
77		return (inet_net_ntop_ipv4(src, bits, dst, size));
78	case AF_INET6:
79		return (inet_net_ntop_ipv6(src, bits, dst, size));
80	default:
81		errno = EAFNOSUPPORT;
82		return (NULL);
83	}
84}
85
86/*
87 * static char *
88 * inet_net_ntop_ipv4(src, bits, dst, size)
89 *	convert IPv4 network number from network to presentation format.
90 *	generates CIDR style result always.
91 * return:
92 *	pointer to dst, or NULL if an error occurred (check errno).
93 * note:
94 *	network byte order assumed.  this means 192.5.5.240/28 has
95 *	0b11110000 in its fourth octet.
96 * author:
97 *	Paul Vixie (ISC), July 1996
98 */
99static char *
100inet_net_ntop_ipv4(src, bits, dst, size)
101	const u_char *src;
102	int bits;
103	char *dst;
104	size_t size;
105{
106	char *odst = dst;
107	char *t;
108	u_int m;
109	int b;
110
111	if (bits < 0 || bits > 32) {
112		errno = EINVAL;
113		return (NULL);
114	}
115
116	if (bits == 0) {
117		if (size < sizeof "0")
118			goto emsgsize;
119		*dst++ = '0';
120		size--;
121		*dst = '\0';
122	}
123
124	/* Format whole octets. */
125	for (b = bits / 8; b > 0; b--) {
126		if (size <= sizeof "255.")
127			goto emsgsize;
128		t = dst;
129		dst += SPRINTF((dst, "%u", *src++));
130		if (b > 1) {
131			*dst++ = '.';
132			*dst = '\0';
133		}
134		size -= (size_t)(dst - t);
135	}
136
137	/* Format partial octet. */
138	b = bits % 8;
139	if (b > 0) {
140		if (size <= sizeof ".255")
141			goto emsgsize;
142		t = dst;
143		if (dst != odst)
144			*dst++ = '.';
145		m = ((1 << b) - 1) << (8 - b);
146		dst += SPRINTF((dst, "%u", *src & m));
147		size -= (size_t)(dst - t);
148	}
149
150	/* Format CIDR /width. */
151	if (size <= sizeof "/32")
152		goto emsgsize;
153	dst += SPRINTF((dst, "/%u", bits));
154	return (odst);
155
156 emsgsize:
157	errno = EMSGSIZE;
158	return (NULL);
159}
160
161/*
162 * static char *
163 * inet_net_ntop_ipv6(src, bits, fakebits, dst, size)
164 *	convert IPv6 network number from network to presentation format.
165 *	generates CIDR style result always. Picks the shortest representation
166 *	unless the IP is really IPv4.
167 *	always prints specified number of bits (bits).
168 * return:
169 *	pointer to dst, or NULL if an error occurred (check errno).
170 * note:
171 *	network byte order assumed.  this means 192.5.5.240/28 has
172 *	0x11110000 in its fourth octet.
173 * author:
174 *	Vadim Kogan (UCB), June 2001
175 *  Original version (IPv4) by Paul Vixie (ISC), July 1996
176 */
177
178static char *
179inet_net_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size) {
180	u_int	m;
181	int	b;
182	size_t	p;
183	size_t	zero_s, zero_l, tmp_zero_s, tmp_zero_l;
184	size_t	i;
185	int	is_ipv4 = 0;
186	unsigned char inbuf[16];
187	char outbuf[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255/128")];
188	char	*cp;
189	size_t	words;
190	u_char	*s;
191
192	if (bits < 0 || bits > 128) {
193		errno = EINVAL;
194		return (NULL);
195	}
196
197	cp = outbuf;
198
199	if (bits == 0) {
200		*cp++ = ':';
201		*cp++ = ':';
202		*cp = '\0';
203	} else {
204		/* Copy src to private buffer.  Zero host part. */
205		p = (bits + 7) / 8;
206		memcpy(inbuf, src, p);
207		memset(inbuf + p, 0, 16 - p);
208		b = bits % 8;
209		if (b != 0) {
210			m = ~0 << (8 - b);
211			inbuf[p-1] &= m;
212		}
213
214		s = inbuf;
215
216		/* how many words need to be displayed in output */
217		words = (bits + 15) / 16;
218		if (words == 1)
219			words = 2;
220
221		/* Find the longest substring of zero's */
222		zero_s = zero_l = tmp_zero_s = tmp_zero_l = 0;
223		for (i = 0; i < (words * 2); i += 2) {
224			if ((s[i] | s[i+1]) == 0) {
225				if (tmp_zero_l == 0)
226					tmp_zero_s = i / 2;
227				tmp_zero_l++;
228			} else {
229				if (tmp_zero_l && zero_l < tmp_zero_l) {
230					zero_s = tmp_zero_s;
231					zero_l = tmp_zero_l;
232					tmp_zero_l = 0;
233				}
234			}
235		}
236
237		if (tmp_zero_l && zero_l < tmp_zero_l) {
238			zero_s = tmp_zero_s;
239			zero_l = tmp_zero_l;
240		}
241
242		if (zero_l != words && zero_s == 0 && ((zero_l == 6) ||
243		    ((zero_l == 5 && s[10] == 0xff && s[11] == 0xff) ||
244		    ((zero_l == 7 && s[14] != 0 && s[15] != 1)))))
245			is_ipv4 = 1;
246
247		/* Format whole words. */
248		for (p = 0; p < words; p++) {
249			if (zero_l != 0 && p >= zero_s && p < zero_s + zero_l) {
250				/* Time to skip some zeros */
251				if (p == zero_s)
252					*cp++ = ':';
253				if (p == words - 1)
254					*cp++ = ':';
255				s++;
256				s++;
257				continue;
258			}
259
260			if (is_ipv4 && p > 5 ) {
261				*cp++ = (p == 6) ? ':' : '.';
262				cp += SPRINTF((cp, "%u", *s++));
263				/* we can potentially drop the last octet */
264				if (p != 7 || bits > 120) {
265					*cp++ = '.';
266					cp += SPRINTF((cp, "%u", *s++));
267				}
268			} else {
269				if (cp != outbuf)
270					*cp++ = ':';
271				cp += SPRINTF((cp, "%x", *s * 256 + s[1]));
272				s += 2;
273			}
274		}
275	}
276	/* Format CIDR /width. */
277	(void)SPRINTF((cp, "/%u", bits));
278	if (strlen(outbuf) + 1 > size)
279		goto emsgsize;
280	strcpy(dst, outbuf);
281
282	return (dst);
283
284emsgsize:
285	errno = EMSGSIZE;
286	return (NULL);
287}
288