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 0285da841507fde4a405c515e292b70354c773f9..10d05ca09c7c9b800c0e5f61048c6f7d1b4963d2 100644 (file)
--- 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 92c1184a243b00345e4d490158cd0c1cd16c9833..98397600eac165df62c91caa6234fb63371c223a 100644 (file)
--- 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;