[PATCH] Add dn_skipname() from OpenBSD

[Natanael Copa]

dn_skipname() is needed by a few applications like yate, wine, kde, libspf2
and probably more.

Fixes https://bugs.busybox.net/show_bug.cgi?id=297

Signed-off-by: Natanael Copa <natanael.copa at gmail.com>
---
 libresolv/resolv.c |   85 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 85 insertions(+), 0 deletions(-)

diff --git a/libresolv/resolv.c b/libresolv/resolv.c
index 38b10ff..c55046d 100644
--- a/libresolv/resolv.c
+++ b/libresolv/resolv.c
@@ -7,7 +7,9 @@
  * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
  */
 
+#include <sys/types.h>
 #include <features.h>
+#include <resolv.h>
 
 void __stub1(void);
 void __stub1(void)
@@ -16,3 +18,86 @@ void __stub1(void)
 }
 link_warning (__stub1, "the `libresolv' library is a stub.  Do you really need it?")
 
+/* taken from OpenBSD source */
+/*
+ * ++Copyright++ 1985, 1993
+ * -
+ * Copyright (c) 1985, 1993
+ *    The Regents of the University of California.  All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * -
+ * Portions Copyright (c) 1993 by Digital Equipment Corporation.
+ * 
+ * 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, and that
+ * the name of Digital Equipment Corporation not be used in advertising or
+ * publicity pertaining to distribution of the document or software without
+ * specific, written prior permission.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
+ * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
+ * CORPORATION 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.
+ * -
+ * --Copyright--
+ */
+
+/*
+ * Skip over a compressed domain name. Return the size or -1.
+ */
+int
+__dn_skipname(const u_char *comp_dn, const u_char *eom)
+{
+	const u_char *cp;
+	int n;
+
+	cp = comp_dn;
+	while (cp < eom && (n = *cp++)) {
+		/*
+		 * check for indirection
+		 */
+		switch (n & INDIR_MASK) {
+		case 0:			/* normal case, n == len */
+			cp += n;
+			continue;
+		case INDIR_MASK:	/* indirection */
+			cp++;
+			break;
+		default:		/* illegal type */
+			return (-1);
+		}
+		break;
+	}
+	if (cp > eom)
+		return (-1);
+	return (cp - comp_dn);
+}
+
-- 
1.6.4.2