1/*
2 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (c) 1995,1999 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#ifndef lint
19static const char rcsid[] = "$Id: ns_samedomain.c,v 1.1.2.2.4.2 2004/03/16 12:34:17 marka Exp $";
20#endif
21#include <sys/cdefs.h>
22__FBSDID("$FreeBSD: head/lib/libc/nameser/ns_samedomain.c 158787 2006-05-21 11:19:36Z ume $");
23
24#include "port_before.h"
25
26#include <sys/types.h>
27#include <arpa/nameser.h>
28#include <errno.h>
29#include <string.h>
30
31#include "port_after.h"
32
33/*
34 * int
35 * ns_samedomain(a, b)
36 * Check whether a name belongs to a domain.
37 * Inputs:
38 * a - the domain whose ancestory is being verified
39 * b - the potential ancestor we're checking against
40 * Return:
41 * boolean - is a at or below b?
42 * Notes:
43 * Trailing dots are first removed from name and domain.
44 * Always compare complete subdomains, not only whether the
45 * domain name is the trailing string of the given name.
46 *
47 * "host.foobar.top" lies in "foobar.top" and in "top" and in ""
48 * but NOT in "bar.top"
49 */
50
51int
52ns_samedomain(const char *a, const char *b) {
53 size_t la, lb;
54 int diff, i, escaped;
55 const char *cp;

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138 return (0);
139
140 /* Now compare aligned trailing substring. */
141 cp = a + diff;
142 return (strncasecmp(cp, b, lb) == 0);
143}
144
145#ifndef _LIBC
146/*
147 * int
148 * ns_subdomain(a, b)
149 * is "a" a subdomain of "b"?
150 */
151int
152ns_subdomain(const char *a, const char *b) {
153 return (ns_samename(a, b) != 1 && ns_samedomain(a, b));
154}
155#endif
156
157/*
158 * int
159 * ns_makecanon(src, dst, dstsize)
160 * make a canonical copy of domain name "src"
161 * notes:
162 * foo -> foo.
163 * foo. -> foo.
164 * foo.. -> foo.
165 * foo\. -> foo\..
166 * foo\\. -> foo\\.
167 */
168
169int
170ns_makecanon(const char *src, char *dst, size_t dstsize) {
171 size_t n = strlen(src);
172
173 if (n + sizeof "." > dstsize) { /* Note: sizeof == 2 */
174 errno = EMSGSIZE;
175 return (-1);
176 }
177 strcpy(dst, src);
178 while (n >= 1U && dst[n - 1] == '.') /* Ends in "." */
179 if (n >= 2U && dst[n - 2] == '\\' && /* Ends in "\." */
180 (n < 3U || dst[n - 3] != '\\')) /* But not "\\." */
181 break;
182 else
183 dst[--n] = '\0';
184 dst[n++] = '.';
185 dst[n] = '\0';
186 return (0);
187}
188
189/*
190 * int
191 * ns_samename(a, b)
192 * determine whether domain name "a" is the same as domain name "b"
193 * return:
194 * -1 on error
195 * 0 if names differ
196 * 1 if names are the same
197 */
198
199int
200ns_samename(const char *a, const char *b) {
201 char ta[NS_MAXDNAME], tb[NS_MAXDNAME];
202
203 if (ns_makecanon(a, ta, sizeof ta) < 0 ||
204 ns_makecanon(b, tb, sizeof tb) < 0)
205 return (-1);
206 if (strcasecmp(ta, tb) == 0)
207 return (1);
208 else
209 return (0);
210}