siptrace: debug messages on net data callbacks

(cherry picked from commit 95f3b4dea5d3f0d57ba79c8e8cd34d2ab30c7193)

src/modules/siptrace/siptrace.c

@@ -2141,9 +2141,12 @@ int siptrace_net_data_recv(sr_event_param_t *evp)
 
 	if(siptrace_exec_evcb_msg(&sto) == DROP_R_F) {
 		/* drop() used in event_route - all done */
+		LM_DBG("skipping processing message due to drop\n");
 		return 0;
 	}
 
+	LM_DBG("processing message mode %d\n", _siptrace_mode);
+
 	if(_siptrace_mode & SIPTRACE_MODE_HEP) {
 		trace_send_hep_duplicate(&sto.body, &sto.fromip, &sto.toip, NULL, NULL);
 	}
@@ -2269,9 +2272,12 @@ int siptrace_net_data_sent(sr_event_param_t *evp)
 
 	if(siptrace_exec_evcb_msg(&sto) == DROP_R_F) {
 		/* drop() used in event_route - all done */
+		LM_DBG("skipping processing message due to drop\n");
 		return 0;
 	}
 
+	LM_DBG("processing message mode %d\n", _siptrace_mode);
+
 	if(_siptrace_mode & SIPTRACE_MODE_HEP) {
 		trace_send_hep_duplicate(&sto.body, &sto.fromip, &sto.toip, NULL, NULL);
 	}