after initiating reestablishment, we need to perform cell reselection immediatly

before cell reselection was postponed to the next TTI but this is not possible in
the case where the serving cell changes.

if the "old" serving cell is no longer suitable, we would directly go to RRC IDLE below.
Therefore we need to select the new serving cell before sending the reestablishment
request.

this is tested in TC_8_5_1_1

srsue/src/stack/rrc/rrc.cc

@@ -1396,13 +1396,13 @@ void rrc::proc_con_restablish_request()
     apply_mac_config_dedicated_default();
 
     // perform cell selection in accordance with the cell selection process as specified in TS 36.304 [4];
-    // ... this happens in rrc::run_tti()
+    start_cell_reselection();
   }
 
   // Check timer...
   if (timers->get(t311)->is_running()) {
-    // Check for synchronism
+    // Wait until we're synced and have obtained SIBs
-    if (serving_cell->in_sync) {
+    if (serving_cell->in_sync && serving_cell->has_sib1() && serving_cell->has_sib2() && serving_cell->has_sib3()) {
       // Perform cell selection in accordance to 36.304
       if (cell_selection_criteria(serving_cell->get_rsrp())) {
         // Actions following cell reselection while T311 is running 5.3.7.3
@@ -1424,7 +1424,8 @@ void rrc::proc_con_restablish_request()
       } else {
         // Upon selecting an inter-RAT cell
         rrc_log->warning("Reestablishment Cell Selection criteria failed.\n");
-        rrc_log->console("Reestablishment Cell Selection criteria failed. in_sync=%d\n", serving_cell->in_sync);
+        rrc_log->console("Reestablishment Cell Selection criteria failed (rsrp=%.2f)\n",
+                         serving_cell->get_rsrp());
         leave_connected();
       }
     } else {
@@ -2621,7 +2622,6 @@ void rrc::handle_con_setup(rrc_conn_setup_s* setup)
 /* Reception of RRCConnectionReestablishment by the UE 5.3.7.5 */
 void rrc::handle_con_reest(rrc_conn_reest_s* setup)
 {
-
   timers->get(t301)->stop();
 
   // Reestablish PDCP and RLC for SRB1