Prevent TCP failures from affecting EDNS stats

EDNS mechanisms only apply to DNS over UDP.  Thus, errors encountered
while sending DNS queries over TCP must not influence EDNS timeout
statistics.

(cherry picked from commit fce3c93ea2ac63cd06faf817abf3c775fe11a33d)

diff --git a/bin/tests/system/legacy/tests.sh b/bin/tests/system/legacy/tests.sh
index abc1ca7682a1f8bb22c502e2726d3f10bab281d8..79254e0db261b0089f0e46aaae17775688758ce7 100755 (executable)
--- a/bin/tests/system/legacy/tests.sh
+++ b/bin/tests/system/legacy/tests.sh
@@ -241,6 +241,18 @@ fi
 if [ $ret != 0 ]; then echo_i "failed"; fi
 status=`expr $status + $ret`
 
+n=`expr $n + 1`
+echo_i "checking that TCP failures do not influence EDNS statistics in the ADB ($n)"
+ret=0
+rndc_dumpdb ns1 -adb || ret=1
+timeouts512=`sed -n "s|.*10\.53\.0\.7.*\[edns \([0-9/][0-9/]*\).*|\1|p" ns1/named_dump.db.test$n | awk -F/ '{print $NF}'`
+if [ $timeouts512 -ne 0 ]; then
+       echo_i "512-byte EDNS timeouts according to ADB: $timeouts512, expected: 0"
+       ret=1
+fi
+if [ $ret != 0 ]; then echo_i "failed"; fi
+status=`expr $status + $ret`
+
 if $SHELL ../testcrypto.sh > /dev/null 2>&1
 then
     $PERL $SYSTEMTESTTOP/stop.pl --use-rndc --port ${CONTROLPORT} legacy ns1

diff --git a/lib/dns/resolver.c b/lib/dns/resolver.c
index 7c65fd9956ce8ab158f0419cc5ad5ac19b1ac034..4cd51d78acd0da54c01d0af8a44853eff7e26d3e 100644 (file)
--- a/lib/dns/resolver.c
+++ b/lib/dns/resolver.c
@@ -890,6 +890,25 @@ resquery_destroy(resquery_t **queryp) {
                empty_bucket(res);
 }
 
+/*%
+ * Update EDNS statistics for a server after not getting a response to a UDP
+ * query sent to it.
+ */
+static void
+update_edns_stats(resquery_t *query) {
+       fetchctx_t *fctx = query->fctx;
+
+       if ((query->options & DNS_FETCHOPT_TCP) != 0) {
+               return;
+       }
+
+       if ((query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
+               dns_adb_ednsto(fctx->adb, query->addrinfo, query->udpsize);
+       } else {
+               dns_adb_timeout(fctx->adb, query->addrinfo);
+       }
+}
+
 static void
 fctx_cancelquery(resquery_t **queryp, dns_dispatchevent_t **deventp,
                 isc_time_t *finish, bool no_response,
@@ -950,11 +969,7 @@ fctx_cancelquery(resquery_t **queryp, dns_dispatchevent_t **deventp,
                        uint32_t value;
                        uint32_t mask;
 
-                       if ((query->options & DNS_FETCHOPT_NOEDNS0) == 0)
-                               dns_adb_ednsto(fctx->adb, query->addrinfo,
-                                              query->udpsize);
-                       else
-                               dns_adb_timeout(fctx->adb, query->addrinfo);
+                       update_edns_stats(query);
 
                        /*
                         * If "forward first;" is used and a forwarder timed