dns: fix transaction handling

When logging is disabled, the app layer would still be flagged
as logging. This caused transactions not to be freed until the
end of the flow as the logged tx id would never increment.

This fix postpones the setting of the app layer parser "logger"
flag to the point where we know the logger is enabled.

src/app-layer-dns-common.c

@@ -159,6 +159,8 @@ DNSTransaction *DNSTransactionAlloc(const uint16_t tx_id) {
  *  \brief Free a DNS TX
  *  \param tx DNS TX to free */
 static void DNSTransactionFree(DNSTransaction *tx) {
+    SCEnter();
+
     DNSQueryEntry *q = NULL;
     while ((q = TAILQ_FIRST(&tx->query_list))) {
         TAILQ_REMOVE(&tx->query_list, q, next);
@@ -177,6 +179,7 @@ static void DNSTransactionFree(DNSTransaction *tx) {
 
     AppLayerDecoderEventsFreeEvents(tx->decoder_events);
     SCFree(tx);
+    SCReturn;
 }
 
 /**
@@ -211,6 +214,7 @@ void DNSStateTransactionFree(void *state, uint64_t tx_id) {
         DNSTransactionFree(tx);
         break;
     }
+    SCReturn;
 }
 
 /** \internal
@@ -252,6 +256,7 @@ void *DNSStateAlloc(void) {
 }
 
 void DNSStateFree(void *s) {
+    SCEnter();
     if (s) {
         DNSState *dns_state = (DNSState *) s;
 
@@ -267,6 +272,7 @@ void DNSStateFree(void *s) {
         SCFree(s);
         s = NULL;
     }
+    SCReturn;
 }
 
 /** \brief Validation checks for DNS request header

src/app-layer-parser.c

@@ -1008,6 +1008,9 @@ static void AppLayerTransactionsCleanup(AppLayerProto *p, AppLayerParserStateSto
         inspect = parser_state_store->inspect_id[1];
     log = parser_state_store->log_id;
 
+    SCLogDebug("inspect %"PRIu64", log %"PRIu64", logger: %s",
+            inspect, log, p->logger ? "true" : "false");
+
     if (p->logger == TRUE) {
         uint64_t min = log < inspect ? log : inspect;
         if (min > 0) {

src/log-dnslog.c

@@ -78,8 +78,6 @@ void TmModuleLogDnsLogRegister (void) {
     OutputRegisterModule(MODULE_NAME, "dns-log", LogDnsLogInitCtx);
 
     /* enable the logger for the app layer */
-    AppLayerRegisterLogger(ALPROTO_DNS_UDP);
-    AppLayerRegisterLogger(ALPROTO_DNS_TCP);
     SCLogDebug("registered %s", MODULE_NAME);
 }
 
@@ -460,6 +458,9 @@ OutputCtx *LogDnsLogInitCtx(ConfNode *conf)
 
     SCLogDebug("DNS log output initialized");
 
+    AppLayerRegisterLogger(ALPROTO_DNS_UDP);
+    AppLayerRegisterLogger(ALPROTO_DNS_TCP);
+
     return output_ctx;
 }