From 73d42fac712538b0afb0d41a7d22cccd3188b54b Mon Sep 17 00:00:00 2001
From: ZorazeAli <zoraze.ali@cttc.es>
Date: Tue, 23 Apr 2019 16:21:07 +0200
Subject: [PATCH] lte: Discard packets arriving after UE context removal at
 EpcEnbApplication

Due to RLF the UE context deletion might get triggered during the reception of a packet by EpcEnbApplication from EpcSgwApplication. This patch will enable  EpcEnbApplication  to discard  such packets.
---
 src/lte/model/epc-enb-application.cc | 15 +++++++++++----
 src/lte/model/epc-pgw-application.cc |  1 +
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/lte/model/epc-enb-application.cc b/src/lte/model/epc-enb-application.cc
index 8805e1c86..becae00ec 100644
--- a/src/lte/model/epc-enb-application.cc
+++ b/src/lte/model/epc-enb-application.cc
@@ -197,8 +197,10 @@ EpcEnbApplication::DoUeContextRelease (uint16_t rnti)
         {
           uint32_t teid = bidIt->second;
           m_teidRbidMap.erase (teid);
+          NS_LOG_INFO ("TEID: " << teid << " erased");
         }
       m_rbidTeidMap.erase (rntiIt);
+      NS_LOG_INFO ("RNTI: " << rntiIt->first << " erased");
     }
 }
 
@@ -295,10 +297,15 @@ EpcEnbApplication::RecvFromS1uSocket (Ptr<Socket> socket)
   packet->RemoveHeader (gtpu);
   uint32_t teid = gtpu.GetTeid ();
   std::map<uint32_t, EpsFlowId_t>::iterator it = m_teidRbidMap.find (teid);
-  NS_ASSERT_MSG (it != m_teidRbidMap.end (), "cell id = " << m_cellId);
-
-  m_rxS1uSocketPktTrace (packet->Copy ());
-  SendToLteSocket (packet, it->second.m_rnti, it->second.m_bid);
+  if (it == m_teidRbidMap.end ())
+    {
+      NS_LOG_WARN ("UE context at cell id " << m_cellId << " not found, discarding packet");
+    }
+  else
+    {
+      m_rxS1uSocketPktTrace (packet->Copy ());
+      SendToLteSocket (packet, it->second.m_rnti, it->second.m_bid);
+    }
 }
 
 void 
diff --git a/src/lte/model/epc-pgw-application.cc b/src/lte/model/epc-pgw-application.cc
index d50cc680b..85231f4a5 100644
--- a/src/lte/model/epc-pgw-application.cc
+++ b/src/lte/model/epc-pgw-application.cc
@@ -423,6 +423,7 @@ EpcPgwApplication::DoRecvDeleteBearerResponse (Ptr<Packet> packet)
   for (auto &epsBearerId : msg.GetEpsBearerIds ())
     {
       // Remove de-activated bearer contexts from PGW side
+      NS_LOG_INFO ("PGW removing bearer " << (uint16_t) epsBearerId << " of IMSI " << imsi);
       ueit->second->RemoveBearer (epsBearerId);
     }
 }