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 /*	$NetBSD: ns_samedomain.c,v 1.2 2004/05/20 20:35:05 christos Exp $	*/

 /*

  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")

  * Copyright (c) 1995,1999 by Internet Software Consortium.

  *

  * Permission to use, copy, modify, and distribute this software for any

  * purpose with or without fee is hereby granted, provided that the above

  * copyright notice and this permission notice appear in all copies.

  *

  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES

  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF

  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR

  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES

  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN

  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT

  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

  */

 /*

  * This version of this file is derived from Android 2.3 "Gingerbread",

  * which contains uncredited changes by Android/Google developers.  It has

  * been modified in 2011 for use in the Android build of Mozilla Firefox by

  * Mozilla contributors (including Michael Edwards <m.k.edwards@gmail.com>,

  * and Steve Workman <sjhworkman@gmail.com>).

  * These changes are offered under the same license as the original NetBSD

  * file, whose copyright and license are unchanged above.

  */

 #define ANDROID_CHANGES 1

 #define MOZILLA_NECKO_EXCLUDE_CODE 1

 #include <sys/cdefs.h>

 #ifndef lint

 #ifdef notdef

 static const char rcsid[] = "Id: ns_samedomain.c,v 1.1.2.2.4.2 2004/03/16 12:34:17 marka Exp";

 #else

 __RCSID("$NetBSD: ns_samedomain.c,v 1.2 2004/05/20 20:35:05 christos Exp $");

 #endif

 #endif

 #include <sys/types.h>

 #include "arpa_nameser.h"

 #include <errno.h>

 #include <string.h>

 #ifndef MOZILLA_NECKO_EXCLUDE_CODE

 #ifndef _LIBC

 /*

  * int

  * ns_samedomain(a, b)

  *	Check whether a name belongs to a domain.

  * Inputs:

  *	a - the domain whose ancestory is being verified

  *	b - the potential ancestor we're checking against

  * Return:

  *	boolean - is a at or below b?

  * Notes:

  *	Trailing dots are first removed from name and domain.

  *	Always compare complete subdomains, not only whether the

  *	domain name is the trailing string of the given name.

  *

  *	"host.foobar.top" lies in "foobar.top" and in "top" and in ""

  *	but NOT in "bar.top"

  */

 int

 ns_samedomain(const char *a, const char *b) {

 	size_t la, lb;

 	int diff, i, escaped;

 	const char *cp;

 	la = strlen(a);

 	lb = strlen(b);

 	/* Ignore a trailing label separator (i.e. an unescaped dot) in 'a'. */

 	if (la != 0U && a[la - 1] == '.') {

 		escaped = 0;

 		/* Note this loop doesn't get executed if la==1. */

 		for (i = la - 2; i >= 0; i--)

 			if (a[i] == '\\') {

 				if (escaped)

 					escaped = 0;

 				else

 					escaped = 1;

 			} else

 				break;

 		if (!escaped)

 			la--;

 	}

 	/* Ignore a trailing label separator (i.e. an unescaped dot) in 'b'. */

 	if (lb != 0U && b[lb - 1] == '.') {

 		escaped = 0;

 		/* note this loop doesn't get executed if lb==1 */

 		for (i = lb - 2; i >= 0; i--)

 			if (b[i] == '\\') {

 				if (escaped)

 					escaped = 0;

 				else

 					escaped = 1;

 			} else

 				break;

 		if (!escaped)

 			lb--;

 	}

 	/* lb == 0 means 'b' is the root domain, so 'a' must be in 'b'. */

 	if (lb == 0U)

 		return (1);

 	/* 'b' longer than 'a' means 'a' can't be in 'b'. */

 	if (lb > la)

 		return (0);

 	/* 'a' and 'b' being equal at this point indicates sameness. */

 	if (lb == la)

 		return (strncasecmp(a, b, lb) == 0);

 	/* Ok, we know la > lb. */

 	diff = la - lb;

 	/*

 	 * If 'a' is only 1 character longer than 'b', then it can't be

 	 * a subdomain of 'b' (because of the need for the '.' label

 	 * separator).

 	 */

 	if (diff < 2)

 		return (0);

 	/*

 	 * If the character before the last 'lb' characters of 'b'

 	 * isn't '.', then it can't be a match (this lets us avoid

 	 * having "foobar.com" match "bar.com").

 	 */

 	if (a[diff - 1] != '.')

 		return (0);

 	/*

 	 * We're not sure about that '.', however.  It could be escaped

          * and thus not a really a label separator.

 	 */

 	escaped = 0;

 	for (i = diff - 2; i >= 0; i--)

 		if (a[i] == '\\') {

 			if (escaped)

 				escaped = 0;

 			else

 				escaped = 1;

 		} else

 			break;

 	if (escaped)

 		return (0);

 	/* Now compare aligned trailing substring. */

 	cp = a + diff;

 	return (strncasecmp(cp, b, lb) == 0);

 }

 /*

  * int

  * ns_subdomain(a, b)

  *	is "a" a subdomain of "b"?

  */

 int

 ns_subdomain(const char *a, const char *b) {

 	return (ns_samename(a, b) != 1 && ns_samedomain(a, b));

 }

 #endif

 #endif

 /*

  * int

  * ns_makecanon(src, dst, dstsize)

  *	make a canonical copy of domain name "src"

  * notes:

  *	foo -> foo.

  *	foo. -> foo.

  *	foo.. -> foo.

  *	foo\. -> foo\..

  *	foo\\. -> foo\\.

  */

 int

 ns_makecanon(const char *src, char *dst, size_t dstsize) {

 	size_t n = strlen(src);

 	if (n + sizeof "." > dstsize) {			/* Note: sizeof == 2 */

 		errno = EMSGSIZE;

 		return (-1);

 	}

 	strcpy(dst, src);

 	while (n >= 1U && dst[n - 1] == '.')		/* Ends in "." */

 		if (n >= 2U && dst[n - 2] == '\\' &&	/* Ends in "\." */

 		    (n < 3U || dst[n - 3] != '\\'))	/* But not "\\." */

 			break;

 		else

 			dst[--n] = '\0';

 	dst[n++] = '.';

 	dst[n] = '\0';

 	return (0);

 }

 /*

  * int

  * ns_samename(a, b)

  *	determine whether domain name "a" is the same as domain name "b"

  * return:

  *	-1 on error

  *	0 if names differ

  *	1 if names are the same

  */

 int

 ns_samename(const char *a, const char *b) {

 	char ta[NS_MAXDNAME], tb[NS_MAXDNAME];

 	if (ns_makecanon(a, ta, sizeof ta) < 0 ||

 	    ns_makecanon(b, tb, sizeof tb) < 0)

 		return (-1);

 	if (strcasecmp(ta, tb) == 0)

 		return (1);

 	else

 		return (0);

 }