support EDNS0 (RFC2671) buffer size notification on DNS queries.

"options edns0" in /etc/resolv.conf will enable the behavior.  no behavior
change if you don't have the line.  see resolv.conf(5) for more details.

EDNS0 is useful for avoiding TCP DNS queries/replies on larger DNS responses.
also, draft-ietf-dnsext-message-size-* plans to mandate EDNS0 support for DNS
clients that support IPv6 transport.

1 files changed, 4 insertions, 2 deletions

diff --git a/src/lib/libc/net/res_debug.c b/src/lib/libc/net/res_debug.c
index e1894b1508..54be69cef7 100644
--- a/src/lib/libc/net/res_debug.c
+++ b/src/lib/libc/net/res_debug.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: res_debug.c,v 1.10 2000/07/07 20:59:47 deraadt Exp $  */
+/*      $OpenBSD: res_debug.c,v 1.11 2001/06/11 10:05:59 itojun Exp $   */
 
 /*
  * ++Copyright++ 1985, 1990, 1993
@@ -82,7 +82,7 @@
 static char sccsid[] = "@(#)res_debug.c 8.1 (Berkeley) 6/4/93";
 static char rcsid[] = "$From: res_debug.c,v 8.19 1996/11/26 10:11:23 vixie Exp $";
 #else
-static char rcsid[] = "$OpenBSD: res_debug.c,v 1.10 2000/07/07 20:59:47 deraadt Exp $";
+static char rcsid[] = "$OpenBSD: res_debug.c,v 1.11 2001/06/11 10:05:59 itojun Exp $";
 #endif
 #endif /* LIBC_SCCS and not lint */
 
@@ -1028,6 +1028,8 @@ __p_option(option)
         case RES_DNSRCH:        return "dnsrch";
         case RES_INSECURE1:     return "insecure1";
         case RES_INSECURE2:     return "insecure2";
+        case RES_USE_INET6:     return "inet6";
+        case RES_USE_EDNS0:     return "edns0";
         default:                sprintf(nbuf, "?0x%lx?", (u_long)option);
                                 return (nbuf);
         }