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 1.4 2017/05/09 02:56:44 maya 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(const u_char *src, int bits,
53					char *dst, size_t size);
54static char *	inet_net_ntop_ipv6(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(int af, const void *src, int bits, char *dst, size_t size)
69{
70	switch (af) {
71	case AF_INET:
72		return (inet_net_ntop_ipv4(src, bits, dst, size));
73	case AF_INET6:
74		return (inet_net_ntop_ipv6(src, bits, dst, size));
75	default:
76		errno = EAFNOSUPPORT;
77		return (NULL);
78	}
79}
80
81/*
82 * static char *
83 * inet_net_ntop_ipv4(src, bits, dst, size)
84 *	convert IPv4 network number from network to presentation format.
85 *	generates CIDR style result always.
86 * return:
87 *	pointer to dst, or NULL if an error occurred (check errno).
88 * note:
89 *	network byte order assumed.  this means 192.5.5.240/28 has
90 *	0b11110000 in its fourth octet.
91 * author:
92 *	Paul Vixie (ISC), July 1996
93 */
94static char *
95inet_net_ntop_ipv4(const u_char *src, int bits, char *dst, size_t size)
96{
97	char *odst = dst;
98	char *t;
99	u_int m;
100	int b;
101
102	if (bits < 0 || bits > 32) {
103		errno = EINVAL;
104		return (NULL);
105	}
106
107	if (bits == 0) {
108		if (size < sizeof "0")
109			goto emsgsize;
110		*dst++ = '0';
111		size--;
112		*dst = '\0';
113	}
114
115	/* Format whole octets. */
116	for (b = bits / 8; b > 0; b--) {
117		if (size <= sizeof "255.")
118			goto emsgsize;
119		t = dst;
120		dst += SPRINTF((dst, "%u", *src++));
121		if (b > 1) {
122			*dst++ = '.';
123			*dst = '\0';
124		}
125		size -= (size_t)(dst - t);
126	}
127
128	/* Format partial octet. */
129	b = bits % 8;
130	if (b > 0) {
131		if (size <= sizeof ".255")
132			goto emsgsize;
133		t = dst;
134		if (dst != odst)
135			*dst++ = '.';
136		m = ((1 << b) - 1) << (8 - b);
137		dst += SPRINTF((dst, "%u", *src & m));
138		size -= (size_t)(dst - t);
139	}
140
141	/* Format CIDR /width. */
142	if (size <= sizeof "/32")
143		goto emsgsize;
144	dst += SPRINTF((dst, "/%u", bits));
145	return (odst);
146
147 emsgsize:
148	errno = EMSGSIZE;
149	return (NULL);
150}
151
152/*
153 * static char *
154 * inet_net_ntop_ipv6(src, bits, fakebits, dst, size)
155 *	convert IPv6 network number from network to presentation format.
156 *	generates CIDR style result always. Picks the shortest representation
157 *	unless the IP is really IPv4.
158 *	always prints specified number of bits (bits).
159 * return:
160 *	pointer to dst, or NULL if an error occurred (check errno).
161 * note:
162 *	network byte order assumed.  this means 192.5.5.240/28 has
163 *	0x11110000 in its fourth octet.
164 * author:
165 *	Vadim Kogan (UCB), June 2001
166 *  Original version (IPv4) by Paul Vixie (ISC), July 1996
167 */
168
169static char *
170inet_net_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size)
171{
172	u_int	m;
173	int	b;
174	size_t	p;
175	size_t	zero_s, zero_l, tmp_zero_s, tmp_zero_l;
176	size_t	i;
177	int	is_ipv4 = 0;
178	unsigned char inbuf[16];
179	char outbuf[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255/128")];
180	char	*cp;
181	size_t	words;
182	u_char	*s;
183
184	if (bits < 0 || bits > 128) {
185		errno = EINVAL;
186		return (NULL);
187	}
188
189	cp = outbuf;
190
191	if (bits == 0) {
192		*cp++ = ':';
193		*cp++ = ':';
194		*cp = '\0';
195	} else {
196		/* Copy src to private buffer.  Zero host part. */
197		p = (bits + 7) / 8;
198		memcpy(inbuf, src, p);
199		memset(inbuf + p, 0, 16 - p);
200		b = bits % 8;
201		if (b != 0) {
202			m = ~0u << (8 - b);
203			inbuf[p-1] &= m;
204		}
205
206		s = inbuf;
207
208		/* how many words need to be displayed in output */
209		words = (bits + 15) / 16;
210		if (words == 1)
211			words = 2;
212
213		/* Find the longest substring of zero's */
214		zero_s = zero_l = tmp_zero_s = tmp_zero_l = 0;
215		for (i = 0; i < (words * 2); i += 2) {
216			if ((s[i] | s[i+1]) == 0) {
217				if (tmp_zero_l == 0)
218					tmp_zero_s = i / 2;
219				tmp_zero_l++;
220			} else {
221				if (tmp_zero_l && zero_l < tmp_zero_l) {
222					zero_s = tmp_zero_s;
223					zero_l = tmp_zero_l;
224					tmp_zero_l = 0;
225				}
226			}
227		}
228
229		if (tmp_zero_l && zero_l < tmp_zero_l) {
230			zero_s = tmp_zero_s;
231			zero_l = tmp_zero_l;
232		}
233
234		if (zero_l != words && zero_s == 0 && ((zero_l == 6) ||
235		    ((zero_l == 5 && s[10] == 0xff && s[11] == 0xff) ||
236		    ((zero_l == 7 && s[14] != 0 && s[15] != 1)))))
237			is_ipv4 = 1;
238
239		/* Format whole words. */
240		for (p = 0; p < words; p++) {
241			if (zero_l != 0 && p >= zero_s && p < zero_s + zero_l) {
242				/* Time to skip some zeros */
243				if (p == zero_s)
244					*cp++ = ':';
245				if (p == words - 1)
246					*cp++ = ':';
247				s++;
248				s++;
249				continue;
250			}
251
252			if (is_ipv4 && p > 5 ) {
253				*cp++ = (p == 6) ? ':' : '.';
254				cp += SPRINTF((cp, "%u", *s++));
255				/* we can potentially drop the last octet */
256				if (p != 7 || bits > 120) {
257					*cp++ = '.';
258					cp += SPRINTF((cp, "%u", *s++));
259				}
260			} else {
261				if (cp != outbuf)
262					*cp++ = ':';
263				cp += SPRINTF((cp, "%x", *s * 256 + s[1]));
264				s += 2;
265			}
266		}
267	}
268	/* Format CIDR /width. */
269	(void)SPRINTF((cp, "/%u", bits));
270	if (strlen(outbuf) + 1 > size)
271		goto emsgsize;
272	strcpy(dst, outbuf);
273
274	return (dst);
275
276emsgsize:
277	errno = EMSGSIZE;
278	return (NULL);
279}
280