1/*
2 * Copyright (C) 1996-2001  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
9 * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
10 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
11 * INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
12 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
13 * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
14 * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
15 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18
19#include "rsync.h"
20
21#define NS_INT16SZ	 2
22#define NS_IN6ADDRSZ	16
23
24/*
25 * WARNING: Don't even consider trying to compile this on a system where
26 * sizeof(int) < 4.  sizeof(int) > 4 is fine; all the world's not a VAX.
27 */
28
29static const char *inet_ntop4(const unsigned char *src, char *dst,
30			      size_t size);
31
32#ifdef AF_INET6
33static const char *inet_ntop6(const unsigned char *src, char *dst,
34			      size_t size);
35#endif
36
37/* char *
38 * isc_net_ntop(af, src, dst, size)
39 *	convert a network format address to presentation format.
40 * return:
41 *	pointer to presentation format address (`dst'), or NULL (see errno).
42 * author:
43 *	Paul Vixie, 1996.
44 */
45const char *
46inet_ntop(int af, const void *src, char *dst, size_t size)
47{
48	switch (af) {
49	case AF_INET:
50		return (inet_ntop4(src, dst, size));
51#ifdef AF_INET6
52	case AF_INET6:
53		return (inet_ntop6(src, dst, size));
54#endif
55	default:
56		errno = EAFNOSUPPORT;
57		return (NULL);
58	}
59	/* NOTREACHED */
60}
61
62/* const char *
63 * inet_ntop4(src, dst, size)
64 *	format an IPv4 address
65 * return:
66 *	`dst' (as a const)
67 * notes:
68 *	(1) uses no statics
69 *	(2) takes a unsigned char* not an in_addr as input
70 * author:
71 *	Paul Vixie, 1996.
72 */
73static const char *
74inet_ntop4(const unsigned char *src, char *dst, size_t size)
75{
76	static const char *fmt = "%u.%u.%u.%u";
77	char tmp[sizeof "255.255.255.255"];
78	size_t len;
79
80	len = snprintf(tmp, sizeof tmp, fmt, src[0], src[1], src[2], src[3]);
81	if (len >= size) {
82		errno = ENOSPC;
83		return (NULL);
84	}
85	memcpy(dst, tmp, len + 1);
86
87	return (dst);
88}
89
90/* const char *
91 * isc_inet_ntop6(src, dst, size)
92 *	convert IPv6 binary address into presentation (printable) format
93 * author:
94 *	Paul Vixie, 1996.
95 */
96#ifdef AF_INET6
97static const char *
98inet_ntop6(const unsigned char *src, char *dst, size_t size)
99{
100	/*
101	 * Note that int32_t and int16_t need only be "at least" large enough
102	 * to contain a value of the specified size.  On some systems, like
103	 * Crays, there is no such thing as an integer variable with 16 bits.
104	 * Keep this in mind if you think this function should have been coded
105	 * to use pointer overlays.  All the world's not a VAX.
106	 */
107	char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
108	struct { int base, len; } best, cur;
109	unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ];
110	int i, inc;
111
112	/*
113	 * Preprocess:
114	 *	Copy the input (bytewise) array into a wordwise array.
115	 *	Find the longest run of 0x00's in src[] for :: shorthanding.
116	 */
117	memset(words, '\0', sizeof words);
118	for (i = 0; i < NS_IN6ADDRSZ; i++)
119		words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
120	best.base = -1;
121	cur.base = -1;
122	for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
123		if (words[i] == 0) {
124			if (cur.base == -1)
125				cur.base = i, cur.len = 1;
126			else
127				cur.len++;
128		} else {
129			if (cur.base != -1) {
130				if (best.base == -1 || cur.len > best.len)
131					best = cur;
132				cur.base = -1;
133			}
134		}
135	}
136	if (cur.base != -1) {
137		if (best.base == -1 || cur.len > best.len)
138			best = cur;
139	}
140	if (best.base != -1 && best.len < 2)
141		best.base = -1;
142
143	/*
144	 * Format the result.
145	 */
146	tp = tmp;
147	for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
148		/* Are we inside the best run of 0x00's? */
149		if (best.base != -1 && i >= best.base &&
150		    i < (best.base + best.len)) {
151			if (i == best.base)
152				*tp++ = ':';
153			continue;
154		}
155		/* Are we following an initial run of 0x00s or any real hex? */
156		if (i != 0)
157			*tp++ = ':';
158		/* Is this address an encapsulated IPv4? */
159		if (i == 6 && best.base == 0 &&
160		    (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
161			if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
162				return (NULL);
163			tp += strlen(tp);
164			break;
165		}
166		inc = snprintf(tp, 5, "%x", words[i]);
167		assert(inc < 5);
168		tp += inc;
169	}
170	/* Was it a trailing run of 0x00's? */
171	if (best.base != -1 && (best.base + best.len) ==
172	    (NS_IN6ADDRSZ / NS_INT16SZ))
173		*tp++ = ':';
174	*tp++ = '\0';
175
176	/*
177	 * Check for overflow, copy, and we're done.
178	 */
179	if ((size_t)(tp - tmp) > size) {
180		errno = ENOSPC;
181		return (NULL);
182	}
183	memcpy(dst, tmp, tp - tmp);
184	return (dst);
185}
186#endif /* AF_INET6 */
187