add support for EDNS0 extended flag DNSSEC OK (aka DO). ok deraadt@

src/include/arpa/nameser.h

@@ -1,4 +1,4 @@
-/*	$OpenBSD: nameser.h,v 1.5 2001/07/25 17:05:46 jakob Exp $	*/
+/*	$OpenBSD: nameser.h,v 1.6 2001/07/31 22:02:18 jakob Exp $	*/
 
 /*
  * ++Copyright++ 1983, 1989, 1993
@@ -248,6 +248,11 @@
 					/* Max length of text sig block */
 #define	MAX_KEY_BASE64			(((MAX_MD5RSA_KEY_BYTES+2)/3)*4)
 
+/*
+ * EDNS0 Z-field extended flags
+ */
+#define DNS_MESSAGEEXTFLAG_DO	0x8000U
+
 /*
  * Status return codes for T_UNSPEC conversion routines
  */

src/include/resolv.h

@@ -1,4 +1,4 @@
-/*	$OpenBSD: resolv.h,v 1.6 2001/06/11 10:06:02 itojun Exp $	*/
+/*	$OpenBSD: resolv.h,v 1.7 2001/07/31 22:02:18 jakob Exp $	*/
 
 /*
  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
@@ -194,6 +194,8 @@ struct __res_state_ext {
 #define	RES_USE_INET6	0x00002000	/* use/map IPv6 in gethostbyname() */
 /* KAME extensions: use higher bit to avoid conflict with ISC use */
 #define	RES_USE_EDNS0	0x40000000	/* use EDNS0 */
+/* DNSSEC extensions: use higher bit to avoid conflict with ISC use */
+#define	RES_USE_DNSSEC	0x20000000	/* use DNSSEC using OK bit in OPT */
 
 #define RES_DEFAULT	(RES_RECURSE | RES_DEFNAMES | RES_DNSRCH)