diff options
| author | Jun-ichiro itojun Hagino <itojun@cvs.openbsd.org> | 2001-06-11 10:06:05 +0000 |
|---|---|---|
| committer | Jun-ichiro itojun Hagino <itojun@cvs.openbsd.org> | 2001-06-11 10:06:05 +0000 |
| commit | 2661edd5e2d7a0106c9507f4de4c44d6fbe5102d (patch) | |
| tree | 7a116003b29bcf48ddb6f76a18479bd911b44af3 /lib/libc/net/res_query.c | |
| parent | 9f4fa9f45bad8232fea1393de0e5ddeb8b9d20c0 (diff) | |
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.
Diffstat (limited to 'lib/libc/net/res_query.c')
| -rw-r--r-- | lib/libc/net/res_query.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/lib/libc/net/res_query.c b/lib/libc/net/res_query.c index 01d1f691cb7..433e80f6482 100644 --- a/lib/libc/net/res_query.c +++ b/lib/libc/net/res_query.c @@ -1,4 +1,4 @@ -/* $OpenBSD: res_query.c,v 1.13 1999/09/27 23:58:26 alex Exp $ */ +/* $OpenBSD: res_query.c,v 1.14 2001/06/11 10:06:01 itojun Exp $ */ /* * ++Copyright++ 1988, 1993 @@ -60,7 +60,7 @@ static char sccsid[] = "@(#)res_query.c 8.1 (Berkeley) 6/4/93"; static char rcsid[] = "$From: res_query.c,v 8.9 1996/09/22 00:13:28 vixie Exp $"; #else -static char rcsid[] = "$OpenBSD: res_query.c,v 1.13 1999/09/27 23:58:26 alex Exp $"; +static char rcsid[] = "$OpenBSD: res_query.c,v 1.14 2001/06/11 10:06:01 itojun Exp $"; #endif #endif /* LIBC_SCCS and not lint */ @@ -87,6 +87,7 @@ static char rcsid[] = "$OpenBSD: res_query.c,v 1.13 1999/09/27 23:58:26 alex Exp const char *hostalias __P((const char *)); int h_errno; +extern int res_opt __P((int, u_char *, int, int)); /* * Formulate a normal query, send, and await answer. @@ -122,6 +123,8 @@ res_query(name, class, type, answer, anslen) n = res_mkquery(QUERY, name, class, type, NULL, 0, NULL, buf, sizeof(buf)); + if (n > 0 && (_res.options & RES_USE_EDNS0) != 0) + n = res_opt(n, buf, sizeof(buf), anslen); if (n <= 0) { #ifdef DEBUG if (_res.options & RES_DEBUG) |