1/*-
2 * SPDX-License-Identifier: ISC
3 *
4 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
5 * Copyright (c) 1996,1999 by Internet Software Consortium.
6 *
7 * Permission to use, copy, modify, and distribute this software for any
8 * purpose with or without fee is hereby granted, provided that the above
9 * copyright notice and this permission notice appear in all copies.
10 *
11 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13 * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
17 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18 */
19
20#include "port_before.h"
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#include "port_after.h"
33
34#ifdef SPRINTF_CHAR
35# define SPRINTF(x) strlen(sprintf/**/x)
36#else
37# define SPRINTF(x) ((size_t)sprintf x)
38#endif
39
40static char *	inet_net_ntop_ipv4(const u_char *src, int bits, char *dst,
41		    size_t size);
42static char *	inet_net_ntop_ipv6(const u_char *src, int bits, char *dst,
43		    size_t size);
44
45/*%
46 * char *
47 * inet_net_ntop(af, src, bits, dst, size)
48 *	convert network number from network to presentation format.
49 *	generates CIDR style result always.
50 * return:
51 *	pointer to dst, or NULL if an error occurred (check errno).
52 * author:
53 *	Paul Vixie (ISC), July 1996
54 */
55char *
56inet_net_ntop(int af, const void *src, int bits, char *dst, size_t size)
57{
58	switch (af) {
59	case AF_INET:
60		return (inet_net_ntop_ipv4(src, bits, dst, size));
61	case AF_INET6:
62		return (inet_net_ntop_ipv6(src, bits, dst, size));
63	default:
64		errno = EAFNOSUPPORT;
65		return (NULL);
66	}
67}
68
69/*%
70 * static char *
71 * inet_net_ntop_ipv4(src, bits, dst, size)
72 *	convert IPv4 network number from network to presentation format.
73 *	generates CIDR style result always.
74 * return:
75 *	pointer to dst, or NULL if an error occurred (check errno).
76 * note:
77 *	network byte order assumed.  this means 192.5.5.240/28 has
78 *	0b11110000 in its fourth octet.
79 * author:
80 *	Paul Vixie (ISC), July 1996
81 */
82static char *
83inet_net_ntop_ipv4(const u_char *src, int bits, char *dst, size_t size)
84{
85	char *odst = dst;
86	char *t;
87	u_int m;
88	int b;
89
90	if (bits < 0 || bits > 32) {
91		errno = EINVAL;
92		return (NULL);
93	}
94
95	if (bits == 0) {
96		if (size < sizeof "0")
97			goto emsgsize;
98		*dst++ = '0';
99		size--;
100		*dst = '\0';
101	}
102
103	/* Format whole octets. */
104	for (b = bits / 8; b > 0; b--) {
105		if (size <= sizeof "255.")
106			goto emsgsize;
107		t = dst;
108		dst += SPRINTF((dst, "%u", *src++));
109		if (b > 1) {
110			*dst++ = '.';
111			*dst = '\0';
112		}
113		size -= (size_t)(dst - t);
114	}
115
116	/* Format partial octet. */
117	b = bits % 8;
118	if (b > 0) {
119		if (size <= sizeof ".255")
120			goto emsgsize;
121		t = dst;
122		if (dst != odst)
123			*dst++ = '.';
124		m = ((1 << b) - 1) << (8 - b);
125		dst += SPRINTF((dst, "%u", *src & m));
126		size -= (size_t)(dst - t);
127	}
128
129	/* Format CIDR /width. */
130	if (size <= sizeof "/32")
131		goto emsgsize;
132	dst += SPRINTF((dst, "/%u", bits));
133	return (odst);
134
135 emsgsize:
136	errno = EMSGSIZE;
137	return (NULL);
138}
139
140/*%
141 * static char *
142 * inet_net_ntop_ipv6(src, bits, fakebits, dst, size)
143 *	convert IPv6 network number from network to presentation format.
144 *	generates CIDR style result always. Picks the shortest representation
145 *	unless the IP is really IPv4.
146 *	always prints specified number of bits (bits).
147 * return:
148 *	pointer to dst, or NULL if an error occurred (check errno).
149 * note:
150 *	network byte order assumed.  this means 192.5.5.240/28 has
151 *	0b11110000 in its fourth octet.
152 * author:
153 *	Vadim Kogan (UCB), June 2001
154 *  Original version (IPv4) by Paul Vixie (ISC), July 1996
155 */
156
157static char *
158inet_net_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size) {
159	u_int	m;
160	int	b;
161	int	p;
162	int	zero_s, zero_l, tmp_zero_s, tmp_zero_l;
163	int	i;
164	int	is_ipv4 = 0;
165	unsigned char inbuf[16];
166	char outbuf[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255/128")];
167	char	*cp;
168	int	words;
169	u_char	*s;
170
171	if (bits < 0 || bits > 128) {
172		errno = EINVAL;
173		return (NULL);
174	}
175
176	cp = outbuf;
177
178	if (bits == 0) {
179		*cp++ = ':';
180		*cp++ = ':';
181		*cp = '\0';
182	} else {
183		/* Copy src to private buffer.  Zero host part. */
184		p = (bits + 7) / 8;
185		memcpy(inbuf, src, p);
186		memset(inbuf + p, 0, 16 - p);
187		b = bits % 8;
188		if (b != 0) {
189			m = ~0 << (8 - b);
190			inbuf[p-1] &= m;
191		}
192
193		s = inbuf;
194
195		/* how many words need to be displayed in output */
196		words = (bits + 15) / 16;
197		if (words == 1)
198			words = 2;
199
200		/* Find the longest substring of zero's */
201		zero_s = zero_l = tmp_zero_s = tmp_zero_l = 0;
202		for (i = 0; i < (words * 2); i += 2) {
203			if ((s[i] | s[i+1]) == 0) {
204				if (tmp_zero_l == 0)
205					tmp_zero_s = i / 2;
206				tmp_zero_l++;
207			} else {
208				if (tmp_zero_l && zero_l < tmp_zero_l) {
209					zero_s = tmp_zero_s;
210					zero_l = tmp_zero_l;
211					tmp_zero_l = 0;
212				}
213			}
214		}
215
216		if (tmp_zero_l && zero_l < tmp_zero_l) {
217			zero_s = tmp_zero_s;
218			zero_l = tmp_zero_l;
219		}
220
221		if (zero_l != words && zero_s == 0 && ((zero_l == 6) ||
222		    ((zero_l == 5 && s[10] == 0xff && s[11] == 0xff) ||
223		    ((zero_l == 7 && s[14] != 0 && s[15] != 1)))))
224			is_ipv4 = 1;
225
226		/* Format whole words. */
227		for (p = 0; p < words; p++) {
228			if (zero_l != 0 && p >= zero_s && p < zero_s + zero_l) {
229				/* Time to skip some zeros */
230				if (p == zero_s)
231					*cp++ = ':';
232				if (p == words - 1)
233					*cp++ = ':';
234				s++;
235				s++;
236				continue;
237			}
238
239			if (is_ipv4 && p > 5 ) {
240				*cp++ = (p == 6) ? ':' : '.';
241				cp += SPRINTF((cp, "%u", *s++));
242				/* we can potentially drop the last octet */
243				if (p != 7 || bits > 120) {
244					*cp++ = '.';
245					cp += SPRINTF((cp, "%u", *s++));
246				}
247			} else {
248				if (cp != outbuf)
249					*cp++ = ':';
250				cp += SPRINTF((cp, "%x", *s * 256 + s[1]));
251				s += 2;
252			}
253		}
254	}
255	/* Format CIDR /width. */
256	sprintf(cp, "/%u", bits);
257	if (strlen(outbuf) + 1 > size)
258		goto emsgsize;
259	strcpy(dst, outbuf);
260
261	return (dst);
262
263emsgsize:
264	errno = EMSGSIZE;
265	return (NULL);
266}
267
268/*
269 * Weak aliases for applications that use certain private entry points,
270 * and fail to include <arpa/inet.h>.
271 */
272#undef inet_net_ntop
273__weak_reference(__inet_net_ntop, inet_net_ntop);
274
275/*! \file */
276