From: Mark Andrews <marka@isc.org>
Date: Tue, 24 Sep 2013 23:57:34 +0000 (+1000)
Subject: 3655.   [cleanup]       Simplify TCP message processing when requesting a
X-Git-Tag: v9.6-ESV-R11b1~53
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b29c34ec5d1e35e43d67ff82bb4a800bb1f77b28;p=thirdparty%2Fbind9.git

3655.   [cleanup]       Simplify TCP message processing when requesting a
                        zone transfer.  [RT #34825]

(cherry picked from commit fb623f9a07857d95cf6c47db0aa81a28c3bbc5c0)
---

diff --git a/CHANGES b/CHANGES
index 0285da84150..10d05ca09c7 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,6 @@
+3655.	[cleanup]	Simplify TCP message processing when requesting a
+			zone transfer.  [RT #34825]
+
 3654.	[bug]		Address race condition with manual notify requests.
 			[RT #34806]
 
diff --git a/lib/dns/xfrin.c b/lib/dns/xfrin.c
index 92c1184a243..98397600eac 100644
--- a/lib/dns/xfrin.c
+++ b/lib/dns/xfrin.c
@@ -221,7 +221,6 @@ static isc_result_t xfrin_start(dns_xfrin_ctx_t *xfr);
 static void xfrin_connect_done(isc_task_t *task, isc_event_t *event);
 static isc_result_t xfrin_send_request(dns_xfrin_ctx_t *xfr);
 static void xfrin_send_done(isc_task_t *task, isc_event_t *event);
-static void xfrin_sendlen_done(isc_task_t *task, isc_event_t *event);
 static void xfrin_recv_done(isc_task_t *task, isc_event_t *event);
 static void xfrin_timeout(isc_task_t *task, isc_event_t *event);
 
@@ -860,8 +859,11 @@ xfrin_create(isc_mem_t *mctx,
 	xfr->sourceaddr = *sourceaddr;
 	isc_sockaddr_setport(&xfr->sourceaddr, 0);
 
-	isc_buffer_init(&xfr->qbuffer, xfr->qbuffer_data,
-			sizeof(xfr->qbuffer_data));
+	/*
+	 * Reserve 2 bytes for TCP length at the begining of the buffer.
+	 */
+	isc_buffer_init(&xfr->qbuffer, &xfr->qbuffer_data[2],
+			sizeof(xfr->qbuffer_data) - 2);
 
 	xfr->magic = XFRIN_MAGIC;
 	*xfrp = xfr;
@@ -1043,10 +1045,8 @@ static isc_result_t
 xfrin_send_request(dns_xfrin_ctx_t *xfr) {
 	isc_result_t result;
 	isc_region_t region;
-	isc_region_t lregion;
 	dns_rdataset_t *qrdataset = NULL;
 	dns_message_t *msg = NULL;
-	unsigned char length[2];
 	dns_difftuple_t *soatuple = NULL;
 	dns_name_t *qname = NULL;
 	dns_dbversion_t *ver = NULL;
@@ -1115,12 +1115,16 @@ xfrin_send_request(dns_xfrin_ctx_t *xfr) {
 	isc_buffer_usedregion(&xfr->qbuffer, &region);
 	INSIST(region.length <= 65535);
 
-	length[0] = region.length >> 8;
-	length[1] = region.length & 0xFF;
-	lregion.base = length;
-	lregion.length = 2;
-	CHECK(isc_socket_send(xfr->socket, &lregion, xfr->task,
-			      xfrin_sendlen_done, xfr));
+	/*
+	 * Record message length and adjust region to include TCP
+	 * length field.
+	 */
+	xfr->qbuffer_data[0] = (region.length >> 8) & 0xff;
+	xfr->qbuffer_data[1] = region.length & 0xff;
+	region.base -= 2;
+	region.length += 2;
+	CHECK(isc_socket_send(xfr->socket, &region, xfr->task,
+			      xfrin_send_done, xfr));
 	xfr->sends++;
 
  failure:
@@ -1137,42 +1141,6 @@ xfrin_send_request(dns_xfrin_ctx_t *xfr) {
 	return (result);
 }
 
-/* XXX there should be library support for sending DNS TCP messages */
-
-static void
-xfrin_sendlen_done(isc_task_t *task, isc_event_t *event) {
-	isc_socketevent_t *sev = (isc_socketevent_t *) event;
-	dns_xfrin_ctx_t *xfr = (dns_xfrin_ctx_t *) event->ev_arg;
-	isc_result_t evresult = sev->result;
-	isc_result_t result;
-	isc_region_t region;
-
-	REQUIRE(VALID_XFRIN(xfr));
-
-	UNUSED(task);
-
-	INSIST(event->ev_type == ISC_SOCKEVENT_SENDDONE);
-	isc_event_free(&event);
-
-	xfr->sends--;
-	if (xfr->shuttingdown) {
-		maybe_free(xfr);
-		return;
-	}
-
-	xfrin_log(xfr, ISC_LOG_DEBUG(3), "sent request length prefix");
-	CHECK(evresult);
-
-	isc_buffer_usedregion(&xfr->qbuffer, &region);
-	CHECK(isc_socket_send(xfr->socket, &region, xfr->task,
-			      xfrin_send_done, xfr));
-	xfr->sends++;
- failure:
-	if (result != ISC_R_SUCCESS)
-		xfrin_fail(xfr, result, "failed sending request length prefix");
-}
-
-
 static void
 xfrin_send_done(isc_task_t *task, isc_event_t *event) {
 	isc_socketevent_t *sev = (isc_socketevent_t *) event;