From 2aa4cd219b1fae15f061ec9753d5a6990ec2ba48 Mon Sep 17 00:00:00 2001
From: jca <jca@openbsd.org>
Date: Sat, 18 Feb 2017 19:23:05 +0000
Subject: Add EDNS0 support.

EDNS allows for various DNS extensions, among which UDP DNS packets size
bigger than 512 bytes.  The default is still to not advertize anything.

ok eric@
---
 lib/libc/asr/asr_utils.c | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

(limited to 'lib/libc/asr/asr_utils.c')

diff --git a/lib/libc/asr/asr_utils.c b/lib/libc/asr/asr_utils.c
index 835d5dfb448..e540aae9ab6 100644
--- a/lib/libc/asr/asr_utils.c
+++ b/lib/libc/asr/asr_utils.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: asr_utils.c,v 1.14 2017/02/17 22:24:45 eric Exp $	*/
+/*	$OpenBSD: asr_utils.c,v 1.15 2017/02/18 19:23:05 jca Exp $	*/
 /*
  * Copyright (c) 2009-2012	Eric Faurot	<eric@faurot.net>
  *
@@ -380,6 +380,14 @@ pack_u16(struct asr_pack *p, uint16_t v)
 	return (pack_data(p, &v, 2));
 }
 
+static int
+pack_u32(struct asr_pack *p, uint32_t v)
+{
+	v = htonl(v);
+
+	return (pack_data(p, &v, 4));
+}
+
 static int
 pack_dname(struct asr_pack *p, const char *dname)
 {
@@ -414,6 +422,18 @@ _asr_pack_query(struct asr_pack *p, uint16_t type, uint16_t class, const char *d
 	return (p->err) ? (-1) : (0);
 }
 
+int
+_asr_pack_edns0(struct asr_pack *p, uint16_t pktsz)
+{
+	pack_dname(p, "");	/* root */
+	pack_u16(p, 41);	/* OPT */
+	pack_u16(p, pktsz);	/* UDP payload size */
+	pack_u32(p, 0);		/* extended RCODE and flags */
+	pack_u16(p, 0);		/* RDATA len */
+
+	return (p->err) ? (-1) : (0);
+}
+
 int
 _asr_sockaddr_from_str(struct sockaddr *sa, int family, const char *str)
 {
-- 
cgit v1.2.3-59-g8ed1b