From f274cbeaed0e4c5fdbde9f5c30833d7f1da37cd3 Mon Sep 17 00:00:00 2001
From: Mark Andrews <marka@isc.org>
Date: Thu, 30 Oct 2014 11:42:02 +1100
Subject: [PATCH] 3992.   [func]          DiG can now send queries without
 questions                         (dig +header-only). [RT #37599]

---
 CHANGES                   |  3 +++
 bin/dig/dig.c             |  5 +++++
 bin/dig/dig.docbook       | 11 +++++++++++
 bin/dig/dighost.c         |  7 +++++--
 bin/dig/include/dig/dig.h |  3 ++-
 doc/arm/notes.xml         |  6 ++++++
 6 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/CHANGES b/CHANGES
index c7301607f1..0b5a2de328 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,6 @@
+3992.	[func]		DiG can now send queries without questions
+			(dig +header-only). [RT #37599]
+
 3991.	[func]		Add the ability to buffer logging output by specifying
 			"buffered yes;" when defining a channel. [RT #26561]
 
diff --git a/bin/dig/dig.c b/bin/dig/dig.c
index 0b4045e338..2a00b058d8 100644
--- a/bin/dig/dig.c
+++ b/bin/dig/dig.c
@@ -230,6 +230,7 @@ help(void) {
 "                 +[no]dnssec         (Request DNSSEC records)\n"
 "                 +[no]expire         (Request time to expire)\n"
 "                 +[no]nsid           (Request Name Server ID)\n"
+"                 +[no]header-only    (Send query without a question section)\n"
 #ifdef ISC_PLATFORM_USESIT
 "                 +[no]sit            (Request a Source Identity Token)\n"
 #endif
@@ -1017,6 +1018,10 @@ plus_option(char *option, isc_boolean_t is_batchfile,
 		FULLCHECK("fail");
 		lookup->servfail_stops = state;
 		break;
+	case 'h':
+		FULLCHECK("header-only");
+		lookup->header_only = state;
+		break;
 	case 'i':
 		switch (cmd[1]) {
 		case 'd': /* identify */
diff --git a/bin/dig/dig.docbook b/bin/dig/dig.docbook
index 5dfbe212df..24fba64ee2 100644
--- a/bin/dig/dig.docbook
+++ b/bin/dig/dig.docbook
@@ -622,6 +622,17 @@
 	  </listitem>
 	</varlistentry>
 
+	<varlistentry>
+	  <term><option>+[no]header-only</option></term>
+	  <listitem>
+	    <para>
+	      Send a query with a DNS header without a question section.
+	      The default is to add a question section.  The query type
+	      and query name are ignored when this is set.
+	    </para>
+	  </listitem>
+	</varlistentry>
+
 	<varlistentry>
 	  <term><option>+[no]identify</option></term>
 	  <listitem>
diff --git a/bin/dig/dighost.c b/bin/dig/dighost.c
index c9e048e20a..7d418804fd 100644
--- a/bin/dig/dighost.c
+++ b/bin/dig/dighost.c
@@ -786,6 +786,7 @@ make_empty_lookup(void) {
 	looknew->ednsflags = 0;
 	looknew->expire = ISC_FALSE;
 	looknew->nsid = ISC_FALSE;
+	looknew->header_only = ISC_FALSE;
 #ifdef ISC_PLATFORM_USESIT
 	looknew->sit = ISC_FALSE;
 #endif
@@ -881,6 +882,7 @@ clone_lookup(dig_lookup_t *lookold, isc_boolean_t servers) {
 	looknew->ednsflags = lookold->ednsflags;
 	looknew->expire = lookold->expire;
 	looknew->nsid = lookold->nsid;
+	looknew->header_only = lookold->header_only;
 #ifdef ISC_PLATFORM_USESIT
 	looknew->sit = lookold->sit;
 	looknew->sitvalue = lookold->sitvalue;
@@ -2431,8 +2433,9 @@ setup_lookup(dig_lookup_t *lookup) {
 		}
 	}
 
-	add_question(lookup->sendmsg, lookup->name, lookup->rdclass,
-		     lookup->rdtype);
+	if (!lookup->header_only)
+		add_question(lookup->sendmsg, lookup->name, lookup->rdclass,
+			     lookup->rdtype);
 
 	/* add_soa */
 	if (lookup->rdtype == dns_rdatatype_ixfr)
diff --git a/bin/dig/include/dig/dig.h b/bin/dig/include/dig/dig.h
index 97e1e7b00c..435e8d539c 100644
--- a/bin/dig/include/dig/dig.h
+++ b/bin/dig/include/dig/dig.h
@@ -135,7 +135,8 @@ struct dig_lookup {
 #ifdef ISC_PLATFORM_USESIT
 		sit,
 #endif
-		nsid;   /*% Name Server ID (RFC 5001) */
+		nsid,   /*% Name Server ID (RFC 5001) */
+		header_only;
 #ifdef DIG_SIGCHASE
 isc_boolean_t	sigchase;
 #if DIG_SIGCHASE_TD
diff --git a/doc/arm/notes.xml b/doc/arm/notes.xml
index bf1c982b21..52480d4e04 100644
--- a/doc/arm/notes.xml
+++ b/doc/arm/notes.xml
@@ -127,6 +127,12 @@
           yet-to-be-defined EDNS flags in DNS requests.
 	</para>
       </listitem>
+      <listitem>
+	<para>
+          <command>dig +header-only</command> can now be used to send
+	  queries without a question section.
+	</para>
+      </listitem>
       <listitem>
 	<para>
           <command>dig +ttlunits</command> causes <command>dig</command>