1/*
2 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (c) 1996,1999 by Internet Software Consortium.
4 *
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.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
15 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18#if defined(LIBC_SCCS) && !defined(lint)
19static const char rcsid[] = "$Id: inet_net_ntop.c,v 1.5 2006/06/20 02:50:14 marka Exp $";
20#endif
21
22#include "port_before.h"
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#include <stdlib.h>
33
34#include "port_after.h"
35
36#ifdef SPRINTF_CHAR
37# define SPRINTF(x) strlen(sprintf/**/x)
38#else
39# define SPRINTF(x) ((size_t)sprintf x)
40#endif
41
42static char *	inet_net_ntop_ipv4 __P((const u_char *src, int bits,
43					char *dst, size_t size));
44static char *	inet_net_ntop_ipv6 __P((const u_char *src, int bits,
45					char *dst, size_t size));
46
47/*%
48 * char *
49 * inet_net_ntop(af, src, bits, dst, size)
50 *	convert network number from network to presentation format.
51 *	generates CIDR style result always.
52 * return:
53 *	pointer to dst, or NULL if an error occurred (check errno).
54 * author:
55 *	Paul Vixie (ISC), July 1996
56 */
57char *
58inet_net_ntop(af, src, bits, dst, size)
59	int af;
60	const void *src;
61	int bits;
62	char *dst;
63	size_t size;
64{
65	switch (af) {
66	case AF_INET:
67		return (inet_net_ntop_ipv4(src, bits, dst, size));
68	case AF_INET6:
69		return (inet_net_ntop_ipv6(src, bits, dst, size));
70	default:
71		errno = EAFNOSUPPORT;
72		return (NULL);
73	}
74}
75
76/*%
77 * static char *
78 * inet_net_ntop_ipv4(src, bits, dst, size)
79 *	convert IPv4 network number from network to presentation format.
80 *	generates CIDR style result always.
81 * return:
82 *	pointer to dst, or NULL if an error occurred (check errno).
83 * note:
84 *	network byte order assumed.  this means 192.5.5.240/28 has
85 *	0b11110000 in its fourth octet.
86 * author:
87 *	Paul Vixie (ISC), July 1996
88 */
89static char *
90inet_net_ntop_ipv4(src, bits, dst, size)
91	const u_char *src;
92	int bits;
93	char *dst;
94	size_t size;
95{
96	char *odst = dst;
97	char *t;
98	u_int m;
99	int b;
100
101	if (bits < 0 || bits > 32) {
102		errno = EINVAL;
103		return (NULL);
104	}
105
106	if (bits == 0) {
107		if (size < sizeof "0")
108			goto emsgsize;
109		*dst++ = '0';
110		size--;
111		*dst = '\0';
112	}
113
114	/* Format whole octets. */
115	for (b = bits / 8; b > 0; b--) {
116		if (size <= sizeof "255.")
117			goto emsgsize;
118		t = dst;
119		dst += SPRINTF((dst, "%u", *src++));
120		if (b > 1) {
121			*dst++ = '.';
122			*dst = '\0';
123		}
124		size -= (size_t)(dst - t);
125	}
126
127	/* Format partial octet. */
128	b = bits % 8;
129	if (b > 0) {
130		if (size <= sizeof ".255")
131			goto emsgsize;
132		t = dst;
133		if (dst != odst)
134			*dst++ = '.';
135		m = ((1 << b) - 1) << (8 - b);
136		dst += SPRINTF((dst, "%u", *src & m));
137		size -= (size_t)(dst - t);
138	}
139
140	/* Format CIDR /width. */
141	if (size <= sizeof "/32")
142		goto emsgsize;
143	dst += SPRINTF((dst, "/%u", bits));
144	return (odst);
145
146 emsgsize:
147	errno = EMSGSIZE;
148	return (NULL);
149}
150
151/*%
152 * static char *
153 * inet_net_ntop_ipv6(src, bits, fakebits, dst, size)
154 *	convert IPv6 network number from network to presentation format.
155 *	generates CIDR style result always. Picks the shortest representation
156 *	unless the IP is really IPv4.
157 *	always prints specified number of bits (bits).
158 * return:
159 *	pointer to dst, or NULL if an error occurred (check errno).
160 * note:
161 *	network byte order assumed.  this means 192.5.5.240/28 has
162 *	0x11110000 in its fourth octet.
163 * author:
164 *	Vadim Kogan (UCB), June 2001
165 *  Original version (IPv4) by Paul Vixie (ISC), July 1996
166 */
167
168static char *
169inet_net_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size) {
170	u_int	m;
171	int	b;
172	int	p;
173	int	zero_s, zero_l, tmp_zero_s, tmp_zero_l;
174	int	i;
175	int	is_ipv4 = 0;
176	unsigned char inbuf[16];
177	char outbuf[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255/128")];
178	char	*cp;
179	int	words;
180	u_char	*s;
181
182	if (bits < 0 || bits > 128) {
183		errno = EINVAL;
184		return (NULL);
185	}
186
187	cp = outbuf;
188
189	if (bits == 0) {
190		*cp++ = ':';
191		*cp++ = ':';
192		*cp = '\0';
193	} else {
194		/* Copy src to private buffer.  Zero host part. */
195		p = (bits + 7) / 8;
196		memcpy(inbuf, src, p);
197		memset(inbuf + p, 0, 16 - p);
198		b = bits % 8;
199		if (b != 0) {
200			m = ~0 << (8 - b);
201			inbuf[p-1] &= m;
202		}
203
204		s = inbuf;
205
206		/* how many words need to be displayed in output */
207		words = (bits + 15) / 16;
208		if (words == 1)
209			words = 2;
210
211		/* Find the longest substring of zero's */
212		zero_s = zero_l = tmp_zero_s = tmp_zero_l = 0;
213		for (i = 0; i < (words * 2); i += 2) {
214			if ((s[i] | s[i+1]) == 0) {
215				if (tmp_zero_l == 0)
216					tmp_zero_s = i / 2;
217				tmp_zero_l++;
218			} else {
219				if (tmp_zero_l && zero_l < tmp_zero_l) {
220					zero_s = tmp_zero_s;
221					zero_l = tmp_zero_l;
222					tmp_zero_l = 0;
223				}
224			}
225		}
226
227		if (tmp_zero_l && zero_l < tmp_zero_l) {
228			zero_s = tmp_zero_s;
229			zero_l = tmp_zero_l;
230		}
231
232		if (zero_l != words && zero_s == 0 && ((zero_l == 6) ||
233		    ((zero_l == 5 && s[10] == 0xff && s[11] == 0xff) ||
234		    ((zero_l == 7 && s[14] != 0 && s[15] != 1)))))
235			is_ipv4 = 1;
236
237		/* Format whole words. */
238		for (p = 0; p < words; p++) {
239			if (zero_l != 0 && p >= zero_s && p < zero_s + zero_l) {
240				/* Time to skip some zeros */
241				if (p == zero_s)
242					*cp++ = ':';
243				if (p == words - 1)
244					*cp++ = ':';
245				s++;
246				s++;
247				continue;
248			}
249
250			if (is_ipv4 && p > 5 ) {
251				*cp++ = (p == 6) ? ':' : '.';
252				cp += SPRINTF((cp, "%u", *s++));
253				/* we can potentially drop the last octet */
254				if (p != 7 || bits > 120) {
255					*cp++ = '.';
256					cp += SPRINTF((cp, "%u", *s++));
257				}
258			} else {
259				if (cp != outbuf)
260					*cp++ = ':';
261				cp += SPRINTF((cp, "%x", *s * 256 + s[1]));
262				s += 2;
263			}
264		}
265	}
266	/* Format CIDR /width. */
267	sprintf(cp, "/%u", bits);
268	if (strlen(outbuf) + 1 > size)
269		goto emsgsize;
270	strcpy(dst, outbuf);
271
272	return (dst);
273
274emsgsize:
275	errno = EMSGSIZE;
276	return (NULL);
277}
278
279#undef inet_net_ntop
280#pragma weak inet_net_ntop = __inet_net_ntop
281