qname minimization: issue a warning only if the server is really broken

diff --git a/bin/tests/system/qmin/tests.sh b/bin/tests/system/qmin/tests.sh
index 43e7358e89b722e29ec86d2ddbe13a0e36913d06..baa67983560da56130faf53b8e6518f062117d08 100755 (executable)
--- a/bin/tests/system/qmin/tests.sh
+++ b/bin/tests/system/qmin/tests.sh
@@ -234,6 +234,13 @@ if [ $ret != 0 ]; then echo_i "failed"; fi
 status=`expr $status + $ret`
 $RNDCCMD 10.53.0.7 flush
 
+n=`expr $n + 1`
+echo_i "information that minimization was unsuccessful for .ugly is logged ($n)"
+ret=0
+grep "success resolving 'icky.icky.icky.ptang.zoop.boing.ugly/A' after disabling qname minimization due to 'FORMERR'" ns7/named.run > /dev/null || ret=1
+if [ $ret != 0 ]; then echo_i "failed"; fi
+status=`expr $status + $ret`
+
 n=`expr $n + 1`
 echo_i "query for .slow is properly minimized when qname-minimization is on ($n)"
 ret=0

diff --git a/lib/dns/resolver.c b/lib/dns/resolver.c
index c3f9b39c2593062e895ea675c78edb19280dfb0b..024620b0cb1abbd68f1ce23bb53b2ff2bef0bebd 100644 (file)
--- a/lib/dns/resolver.c
+++ b/lib/dns/resolver.c
@@ -305,11 +305,12 @@ struct fetchctx {
        ISC_LIST(dns_validator_t)       validators;
        dns_db_t *                      cache;
        dns_adb_t *                     adb;
-       bool                    ns_ttl_ok;
+       bool                            ns_ttl_ok;
        uint32_t                        ns_ttl;
        isc_counter_t *                 qc;
-       bool                    minimized;
+       bool                            minimized;
        unsigned int                    qmin_labels;
+       isc_result_t                    qmin_warning;
        bool                            ip6arpaskip;
        bool                            forwarding;
        dns_name_t                      qminname;
@@ -1664,8 +1665,6 @@ log_edns(fetchctx_t *fctx) {
                      DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO,
                      "success resolving '%s' (in '%s'?) after %s",
                      fctx->info, domainbuf, fctx->reason);
-
-       fctx->reason = NULL;
 }
 
 static void
@@ -1686,9 +1685,19 @@ fctx_done(fetchctx_t *fctx, isc_result_t result, int line) {
                 */
                log_edns(fctx);
                no_response = true;
-       } else if (result == ISC_R_TIMEDOUT)
+               if (fctx->qmin_warning != ISC_R_SUCCESS) {
+                       isc_log_write(dns_lctx, DNS_LOGCATEGORY_LAME_SERVERS,
+                                     DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO,
+                                     "success resolving '%s' "
+                                     "after disabling qname minimization due to '%s'",
+                                     fctx->info,
+                                     isc_result_totext(fctx->qmin_warning));
+               }
+       } else if (result == ISC_R_TIMEDOUT) {
                age_untried = true;
+       }
 
+       fctx->qmin_warning = ISC_R_SUCCESS;
        fctx->reason = NULL;
 
        fctx_stopqueries(fctx, no_response, age_untried);
@@ -4101,11 +4110,12 @@ resume_qmin(isc_task_t *task, isc_event_t *event) {
            result == DNS_R_REMOTEFORMERR)
        {
                if ((fctx->options & DNS_FETCHOPT_QMIN_STRICT) == 0) {
-                       isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
-                                     DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO,
-                                     "disabling qname minimization for '%s' "
-                                     "due to nxdomain", fctx->info);
                        fctx->qmin_labels = DNS_MAX_LABELS + 1;
+                       /*
+                        * We store the result. If we succeed in the end
+                        * we'll issue a warning that the server is broken.
+                        */
+                       fctx->qmin_warning = result;
                } else {
                        fctx_done(fctx, result, __LINE__);
                        goto cleanup;
@@ -4683,6 +4693,7 @@ fctx_create(dns_resolver_t *res, const dns_name_t *name, dns_rdatatype_t type,
        fctx->ip6arpaskip = false;
        fctx->forwarding = false;
        fctx->qmin_labels = 1;
+       fctx->qmin_warning = ISC_R_SUCCESS;
        fctx->qminfetch = NULL;
        dns_rdataset_init(&fctx->qminrrset);
        dns_name_init(&fctx->qmindcname, NULL);