fixup previous bad merge (UE disconnection did not work properly anymore)

Doing airplane mode off to connect a cots UE followed by airplane mode on
to disconnect it gives very bad results (bad disconnection with lots of
UL failures followed by lots of logs in the eNB). It used to work properly
after the work done by Xu Bo.

It turns out that in 2018.w04 things were still working okay. But
in 2018.w05 no.

So I ran:

    git diff 2018.w04 2018.w05

And I checked all the modifications that I thought were relevant
(everything related to the UE, oaisim, if4 and fapi has not been checked).

This commits takes back the version of 2018.w04.

The modifications in openair2/RRC/LITE/rrc_eNB.c are necessary, I think.

The other modifications may not be necessary or even wrong. To be checked
at some point.

openair1/PHY/LTE_TRANSPORT/dci_tools.c

@@ -6556,7 +6556,7 @@ uint8_t pdcch_alloc2ul_subframe(LTE_DL_FRAME_PARMS *frame_parms,uint8_t n)
   else
     ul_subframe = ((n+4)%10);
 
-  //  AssertFatal(frame_parms->frame_type == FDD || subframe_select(frame_parms,ul_subframe) == SF_UL,"illegal ul_subframe %d (n %d)\n",ul_subframe,n);
+  AssertFatal(frame_parms->frame_type == FDD || subframe_select(frame_parms,ul_subframe) == SF_UL,"illegal ul_subframe %d (n %d)\n",ul_subframe,n);
 
   LOG_D(PHY, "subframe %d: PUSCH subframe = %d\n", n, ul_subframe);
   return ul_subframe;

openair1/SCHED/fapi_l1.c

@@ -629,7 +629,8 @@ void schedule_response(Sched_Rsp_t *Sched_INFO)
   fp          = &eNB->frame_parms;
   proc        = &eNB->proc.proc_rxtx[0];
 
-  if ((fp->frame_type == TDD) && (subframe_select(fp,subframe)==SF_UL)) return;
+  /* TODO: check that following line is correct - in the meantime it is disabled */
+  //if ((fp->frame_type == TDD) && (subframe_select(fp,subframe)==SF_UL)) return;
 
   ul_subframe = pdcch_alloc2ul_subframe(fp,subframe);
   ul_frame    = pdcch_alloc2ul_frame(fp,frame,subframe);
@@ -664,8 +665,10 @@ void schedule_response(Sched_Rsp_t *Sched_INFO)
 
   int do_oai =0;
   int dont_send =0;
-  if ((ul_subframe<10)&&
-      (subframe_select(fp,ul_subframe)==SF_UL)) { // This means that there is an ul_subframe that can be configured here
+  /* TODO: check the following test - in the meantime it is put back as it was before */
+  //if ((ul_subframe<10)&&
+  //    (subframe_select(fp,ul_subframe)==SF_UL)) { // This means that there is an ul_subframe that can be configured here
+  if (ul_subframe<10) { // This means that there is an ul_subframe that can be configured here
     LOG_D(PHY,"NFAPI: Clearing dci allocations for potential UL subframe %d\n",ul_subframe);
   
     harq_pid = subframe2harq_pid(fp,ul_frame,ul_subframe);

openair1/SCHED/phy_procedures_lte_eNb.c

@@ -452,8 +452,10 @@ void phy_procedures_eNB_TX(PHY_VARS_eNB *eNB,
   }
 
   /* save old HARQ information needed for PHICH generation */
-  if ((ul_subframe < 10)&&
-      (subframe_select(fp,ul_subframe)==SF_UL)) { // This means that there is a potential UL subframe that will be scheduled here
+  /* TODO: check the following test - in the meantime it is put back as it was before */
+  //if ((ul_subframe < 10)&&
+  //    (subframe_select(fp,ul_subframe)==SF_UL)) { // This means that there is a potential UL subframe that will be scheduled here
+  if (ul_subframe < 10) { // This means that there is a potential UL subframe that will be scheduled here
     for (i=0; i<NUMBER_OF_UE_MAX; i++) {
       harq_pid = subframe2harq_pid(fp,ul_frame,ul_subframe);
       if (eNB->ulsch[i]) {

openair2/LAYER2/PDCP_v10.1.0/pdcp.c

@@ -634,6 +634,7 @@ pdcp_data_ind(
 		   rb_id,
 		   sdu_buffer_sizeP - pdcp_header_len - pdcp_tailer_len,
 		   (uint8_t*)&sdu_buffer_pP->data[pdcp_header_len]);
+        free_mem_block(sdu_buffer_pP, __func__);
 
 
       // free_mem_block(new_sdu, __func__);

openair2/RRC/LITE/rrc_eNB.c

@@ -6682,26 +6682,58 @@ rrc_rx_tx(
     RB_FOREACH(ue_context_p, rrc_ue_tree_s, &(RC.rrc[ctxt_pP->module_id]->rrc_ue_head)) {
       if ((ctxt_pP->frame == 0) && (ctxt_pP->subframe==0)) {
 	if (ue_context_p->ue_context.Initialue_identity_s_TMSI.presence == TRUE) {
-	  LOG_I(RRC,"UE rnti %x:S-TMSI %x failure timer %d/20000\n",
+	  LOG_I(RRC,"UE rnti %x:S-TMSI %x failure timer %d/8\n",
 		ue_context_p->ue_context.rnti,
 		ue_context_p->ue_context.Initialue_identity_s_TMSI.m_tmsi,
 		ue_context_p->ue_context.ul_failure_timer);
 	}
 	else {
-	  LOG_I(RRC,"UE rnti %x failure timer %d/20000\n",
+	  LOG_I(RRC,"UE rnti %x failure timer %d/8\n",
 		ue_context_p->ue_context.rnti,
 		ue_context_p->ue_context.ul_failure_timer);
 	}
       }
       if (ue_context_p->ue_context.ul_failure_timer>0) {
 	ue_context_p->ue_context.ul_failure_timer++;
-	if (ue_context_p->ue_context.ul_failure_timer >= 20000) {
+	if (ue_context_p->ue_context.ul_failure_timer >= 8) {
 	  // remove UE after 20 seconds after MAC has indicated UL failure
 	  LOG_I(RRC,"Removing UE %x instance\n",ue_context_p->ue_context.rnti);
 	  ue_to_be_removed = ue_context_p;
 	  break;
 	}
       }
+      if (ue_context_p->ue_context.ue_release_timer_s1>0) {
+        ue_context_p->ue_context.ue_release_timer_s1++;
+        if (ue_context_p->ue_context.ue_release_timer_s1 >=
+            ue_context_p->ue_context.ue_release_timer_thres_s1) {
+          LOG_I(RRC,"Removing UE %x instance Because of UE_CONTEXT_RELEASE_COMMAND not received after %d ms from sending request\n",
+                         ue_context_p->ue_context.rnti, ue_context_p->ue_context.ue_release_timer_thres_s1);
+          ue_to_be_removed = ue_context_p;
+          break;
+        }
+      }
+
+      if (ue_context_p->ue_context.ue_release_timer_rrc>0) {
+        ue_context_p->ue_context.ue_release_timer_rrc++;
+        if (ue_context_p->ue_context.ue_release_timer_rrc >=
+          ue_context_p->ue_context.ue_release_timer_thres_rrc) {
+          LOG_I(RRC,"Removing UE %x instance After UE_CONTEXT_RELEASE_Complete\n", ue_context_p->ue_context.rnti);
+          ue_to_be_removed = ue_context_p;
+          break;
+        }
+      }
+
+      if (ue_context_p->ue_context.ue_reestablishment_timer>0) {
+        ue_context_p->ue_context.ue_reestablishment_timer++;
+        if (ue_context_p->ue_context.ue_reestablishment_timer >=
+            ue_context_p->ue_context.ue_reestablishment_timer_thres) {
+          LOG_I(RRC,"UE %d reestablishment_timer max\n",ue_context_p->ue_context.rnti);
+          ue_context_p->ue_context.ul_failure_timer = 20000;
+          ue_to_be_removed = ue_context_p;
+          ue_context_p->ue_context.ue_reestablishment_timer = 0;
+          break;
+        }
+      }
       if (ue_context_p->ue_context.ue_release_timer>0) {
 	ue_context_p->ue_context.ue_release_timer++;
 	if (ue_context_p->ue_context.ue_release_timer >= 
@@ -6712,8 +6744,18 @@ rrc_rx_tx(
 	}
       }
     }
-    if (ue_to_be_removed)
+    if (ue_to_be_removed) {
+      if(ue_to_be_removed->ue_context.ul_failure_timer >= 8) {
+          ue_to_be_removed->ue_context.ue_release_timer_s1 = 1;
+          ue_to_be_removed->ue_context.ue_release_timer_thres_s1 = 100;
+          ue_to_be_removed->ue_context.ue_release_timer = 0;
+          ue_to_be_removed->ue_context.ue_reestablishment_timer = 0;
+      }
       rrc_eNB_free_UE(ctxt_pP->module_id,ue_to_be_removed);
+      if(ue_to_be_removed->ue_context.ul_failure_timer >= 8){
+        ue_to_be_removed->ue_context.ul_failure_timer = 0;
+      }
+    }
 
 #ifdef RRC_LOCALIZATION