PageRenderTime 16ms CodeModel.GetById 2ms app.highlight 11ms RepoModel.GetById 1ms app.codeStats 0ms

/contrib/bind9/lib/isc/inet_ntop.c

https://bitbucket.org/freebsd/freebsd-head/
C | 199 lines | 112 code | 17 blank | 70 comment | 48 complexity | 1c27cad0dae5ba442bac60657191b395 MD5 | raw file
  1/*
  2 * Copyright (C) 2004, 2005, 2007, 2009  Internet Systems Consortium, Inc. ("ISC")
  3 * Copyright (C) 1996-2001  Internet Software Consortium.
  4 *
  5 * Permission to use, copy, modify, and/or 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 WITH
 10 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 11 * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
 12 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 13 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
 14 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 15 * PERFORMANCE OF THIS SOFTWARE.
 16 */
 17
 18/*! \file */
 19
 20#if defined(LIBC_SCCS) && !defined(lint)
 21static char rcsid[] =
 22	"$Id: inet_ntop.c,v 1.21 2009/07/17 23:47:41 tbox Exp $";
 23#endif /* LIBC_SCCS and not lint */
 24
 25#include <config.h>
 26
 27#include <errno.h>
 28#include <stdio.h>
 29#include <string.h>
 30
 31#include <isc/net.h>
 32#include <isc/print.h>
 33
 34#define NS_INT16SZ	 2
 35#define NS_IN6ADDRSZ	16
 36
 37/*
 38 * WARNING: Don't even consider trying to compile this on a system where
 39 * sizeof(int) < 4.  sizeof(int) > 4 is fine; all the world's not a VAX.
 40 */
 41
 42static const char *inet_ntop4(const unsigned char *src, char *dst,
 43			      size_t size);
 44
 45#ifdef AF_INET6
 46static const char *inet_ntop6(const unsigned char *src, char *dst,
 47			      size_t size);
 48#endif
 49
 50/*! char *
 51 * isc_net_ntop(af, src, dst, size)
 52 *	convert a network format address to presentation format.
 53 * \return
 54 *	pointer to presentation format address (`dst'), or NULL (see errno).
 55 * \author
 56 *	Paul Vixie, 1996.
 57 */
 58const char *
 59isc_net_ntop(int af, const void *src, char *dst, size_t size)
 60{
 61	switch (af) {
 62	case AF_INET:
 63		return (inet_ntop4(src, dst, size));
 64#ifdef AF_INET6
 65	case AF_INET6:
 66		return (inet_ntop6(src, dst, size));
 67#endif
 68	default:
 69		errno = EAFNOSUPPORT;
 70		return (NULL);
 71	}
 72	/* NOTREACHED */
 73}
 74
 75/*! const char *
 76 * inet_ntop4(src, dst, size)
 77 *	format an IPv4 address
 78 * \return
 79 *	`dst' (as a const)
 80 * \note
 81 *	(1) uses no statics
 82 * \note
 83 *	(2) takes a unsigned char* not an in_addr as input
 84 * \author
 85 *	Paul Vixie, 1996.
 86 */
 87static const char *
 88inet_ntop4(const unsigned char *src, char *dst, size_t size)
 89{
 90	static const char *fmt = "%u.%u.%u.%u";
 91	char tmp[sizeof("255.255.255.255")];
 92
 93	if ((size_t)sprintf(tmp, fmt, src[0], src[1], src[2], src[3]) >= size)
 94	{
 95		errno = ENOSPC;
 96		return (NULL);
 97	}
 98	strcpy(dst, tmp);
 99
100	return (dst);
101}
102
103/*! const char *
104 * isc_inet_ntop6(src, dst, size)
105 *	convert IPv6 binary address into presentation (printable) format
106 * \author
107 *	Paul Vixie, 1996.
108 */
109#ifdef AF_INET6
110static const char *
111inet_ntop6(const unsigned char *src, char *dst, size_t size)
112{
113	/*
114	 * Note that int32_t and int16_t need only be "at least" large enough
115	 * to contain a value of the specified size.  On some systems, like
116	 * Crays, there is no such thing as an integer variable with 16 bits.
117	 * Keep this in mind if you think this function should have been coded
118	 * to use pointer overlays.  All the world's not a VAX.
119	 */
120	char tmp[sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")], *tp;
121	struct { int base, len; } best, cur;
122	unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ];
123	int i;
124
125	/*
126	 * Preprocess:
127	 *	Copy the input (bytewise) array into a wordwise array.
128	 *	Find the longest run of 0x00's in src[] for :: shorthanding.
129	 */
130	memset(words, '\0', sizeof(words));
131	for (i = 0; i < NS_IN6ADDRSZ; i++)
132		words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
133	best.base = -1;
134	cur.base = -1;
135	for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
136		if (words[i] == 0) {
137			if (cur.base == -1)
138				cur.base = i, cur.len = 1;
139			else
140				cur.len++;
141		} else {
142			if (cur.base != -1) {
143				if (best.base == -1 || cur.len > best.len)
144					best = cur;
145				cur.base = -1;
146			}
147		}
148	}
149	if (cur.base != -1) {
150		if (best.base == -1 || cur.len > best.len)
151			best = cur;
152	}
153	if (best.base != -1 && best.len < 2)
154		best.base = -1;
155
156	/*
157	 * Format the result.
158	 */
159	tp = tmp;
160	for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
161		/* Are we inside the best run of 0x00's? */
162		if (best.base != -1 && i >= best.base &&
163		    i < (best.base + best.len)) {
164			if (i == best.base)
165				*tp++ = ':';
166			continue;
167		}
168		/* Are we following an initial run of 0x00s or any real hex? */
169		if (i != 0)
170			*tp++ = ':';
171		/* Is this address an encapsulated IPv4? */
172		if (i == 6 && best.base == 0 && (best.len == 6 ||
173		    (best.len == 7 && words[7] != 0x0001) ||
174		    (best.len == 5 && words[5] == 0xffff))) {
175			if (!inet_ntop4(src+12, tp,
176					sizeof(tmp) - (tp - tmp)))
177				return (NULL);
178			tp += strlen(tp);
179			break;
180		}
181		tp += sprintf(tp, "%x", words[i]);
182	}
183	/* Was it a trailing run of 0x00's? */
184	if (best.base != -1 && (best.base + best.len) ==
185	    (NS_IN6ADDRSZ / NS_INT16SZ))
186		*tp++ = ':';
187	*tp++ = '\0';
188
189	/*
190	 * Check for overflow, copy, and we're done.
191	 */
192	if ((size_t)(tp - tmp) > size) {
193		errno = ENOSPC;
194		return (NULL);
195	}
196	strcpy(dst, tmp);
197	return (dst);
198}
199#endif /* AF_INET6 */