pdcp_fifo.c

/*
 * Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The OpenAirInterface Software Alliance licenses this file to You under
 * the OAI Public License, Version 1.1  (the "License"); you may not use this file
 * except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.openairinterface.org/?page_id=698
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *-------------------------------------------------------------------------------
 * For more information about the OpenAirInterface (OAI) Software Alliance:
 *      contact@openairinterface.org
 */

/*! \file pdcp_fifo.c
 * \brief pdcp interface with linux IP interface, have a look at http://man7.org/linux/man-pages/man7/netlink.7.html for netlink
 * \author  Navid Nikaein and Lionel GAUTHIER
 * \date 2009 - 2016
 * \version 0.5
 * \email navid.nikaein@eurecom.fr
 * \warning This component can be runned only in user-space
 * @ingroup pdcp
 */

#define PDCP_FIFO_C
#define PDCP_DEBUG 1
#define DEBUG_PDCP_FIFO_FLUSH_SDU

extern int otg_enabled;

#include "pdcp.h"
#include "pdcp_primitives.h"

#include <pthread.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#define rtf_put write
#define rtf_get read

#include "../MAC/mac_extern.h"
#include "RRC/L2_INTERFACE/openair_rrc_L2_interface.h"
#include "NETWORK_DRIVER/LITE/constant.h"
//#include "SIMULATION/ETH_TRANSPORT/extern.h"
#include "UTIL/OCG/OCG.h"
#include "UTIL/OCG/OCG_extern.h"
#include "common/utils/LOG/log.h"
#include "UTIL/OTG/otg_tx.h"
#include "UTIL/FIFO/pad_list.h"
#include "common/utils/LOG/vcd_signal_dumper.h"
#include "platform_constants.h"
#include "msc.h"
#include "pdcp.h"

#include "assertions.h"

#ifdef PDCP_USE_NETLINK
#include <sys/socket.h>
#include <linux/netlink.h>
#include "NETWORK_DRIVER/UE_IP/constant.h"

extern char nl_rx_buf[NL_MAX_PAYLOAD];
extern struct sockaddr_nl nas_src_addr, nas_dest_addr;
extern struct nlmsghdr *nas_nlh_tx;
extern struct nlmsghdr *nas_nlh_rx;
extern struct iovec nas_iov_tx;
extern struct iovec nas_iov_rx;
#ifdef UE_NAS_USE_TUN
extern int nas_sock_fd[MAX_MOBILES_PER_ENB];
#else
extern int nas_sock_fd;
#endif
extern struct msghdr nas_msg_tx;
extern struct msghdr nas_msg_rx;

unsigned char pdcp_read_state_g = 0;
extern uint8_t nfapi_mode;
#ifdef UESIM_EXPANSION
extern uint16_t inst_pdcp_list[NUMBER_OF_UE_MAX];
#endif
#endif

extern Packet_OTG_List_t *otg_pdcp_buffer;
#if defined(LINK_ENB_PDCP_TO_GTPV1U)
#  include "gtpv1u_eNB_task.h"
#  include "gtpv1u_eNB_defs.h"
#endif

extern int gtpv1u_new_data_req( uint8_t  enb_module_idP, rnti_t   ue_rntiP, uint8_t  rab_idP, uint8_t *buffer_pP, uint32_t buf_lenP, uint32_t buf_offsetP);

/* Prevent de-queueing the same PDCP SDU from the queue twice
 * by multiple threads. This has happened in TDD when thread-odd
 * is flushing a PDCP SDU after UE_RX() processing; whereas
 * thread-even is at a special-subframe, skips the UE_RX() process
 * and goes straight to the PDCP SDU flushing. The 2nd flushing
 * dequeues the same SDU again causing unexpected behavior.
 *
 * comment out the MACRO below to disable this protection
 */
#define PDCP_SDU_FLUSH_LOCK

#ifdef PDCP_SDU_FLUSH_LOCK
static pthread_mutex_t mtex = PTHREAD_MUTEX_INITIALIZER;
#endif

pdcp_data_req_header_t pdcp_read_header_g;

//-----------------------------------------------------------------------------
int pdcp_fifo_flush_sdus(const protocol_ctxt_t* const  ctxt_pP)
{
   //-----------------------------------------------------------------------------

   //#if defined(PDCP_USE_NETLINK) && defined(LINUX)
   int ret = 0;
   //#endif

#ifdef DEBUG_PDCP_FIFO_FLUSH_SDU
#define THREAD_NAME_LEN 16
   static char threadname[THREAD_NAME_LEN];
   ret = pthread_getname_np(pthread_self(), threadname, THREAD_NAME_LEN);
   if (ret != 0)
   {
      perror("pthread_getname_np : ");
      exit_fun("Error getting thread name");
   }
#undef THREAD_NAME_LEN
#endif

#ifdef PDCP_SDU_FLUSH_LOCK
   ret = pthread_mutex_trylock(&mtex);
   if (ret == EBUSY) {
#ifdef DEBUG_PDCP_FIFO_FLUSH_SDU
      LOG_W(PDCP, "[%s] at SFN/SF=%d/%d wait for PDCP FIFO to be unlocked\n",
            threadname, ctxt_pP->frame, ctxt_pP->subframe);
#endif
      if (pthread_mutex_lock(&mtex)) {
         exit_fun("PDCP_SDU_FLUSH_LOCK lock error!");
      }
#ifdef DEBUG_PDCP_FIFO_FLUSH_SDU
      LOG_I(PDCP, "[%s] at SFN/SF=%d/%d PDCP FIFO is unlocked\n",
            threadname, ctxt_pP->frame, ctxt_pP->subframe);
#endif
   } else if (ret != 0) {
      exit_fun("PDCP_SDU_FLUSH_LOCK trylock error!");
   }

#endif

   mem_block_t     *sdu_p            = list_get_head (&pdcp_sdu_list);
   int              bytes_wrote      = 0;
   int              pdcp_nb_sdu_sent = 0;
   uint8_t          cont             = 1;
#if defined(LINK_ENB_PDCP_TO_GTPV1U)
   //MessageDef      *message_p        = NULL;
#endif

   VCD_SIGNAL_DUMPER_DUMP_FUNCTION_BY_NAME( VCD_SIGNAL_DUMPER_FUNCTIONS_PDCP_FIFO_FLUSH, 1 );
   while (sdu_p && cont) { //&& sdu_p!=0x01 && sdu_p!=0x02 && sdu_p!=0x100000000 && sdu_p!=0x200000000

#ifdef DEBUG_PDCP_FIFO_FLUSH_SDU
      LOG_D(PDCP, "[%s] SFN/SF=%d/%d inst=%d size=%d\n",
            threadname, ctxt_pP->frame, ctxt_pP->subframe,
            ((pdcp_data_ind_header_t*) sdu_p->data)->inst,
            ((pdcp_data_ind_header_t *) sdu_p->data)->data_size);
#else
      // Raphael: was suppressed by Raymond --> should be suppressed?
      // value of sdu_p->data->inst is set in pdcp_data_ind
      // it's necessary to set 1 in case of UE with S1.
      //if (ctxt_pP->enb_flag){
      //  ((pdcp_data_ind_header_t *)(sdu_p->data))->inst = 0;
      //}
#endif

#if (LTE_RRC_VERSION >= MAKE_VERSION(14, 0, 0))
      //TTN (29/05/18) OIP1 for UE-eNB, OIP0 for UE-UE (incoming packets)
      //for the  moment, based on rb_id, we distinguish between the traffic from eNB and from other UE

      //traffic from other UE
      if ( ((pdcp_data_ind_header_t *)(sdu_p->data))->rb_id >= 4) {
         ((pdcp_data_ind_header_t *)(sdu_p->data))->inst = 0;
      } else
#endif
      { //traffic from eNB
         ((pdcp_data_ind_header_t *)(sdu_p->data))->inst = 1;
      }

#if defined(LINK_ENB_PDCP_TO_GTPV1U)

      if (ctxt_pP->enb_flag) {
         AssertFatal(0, "Now execution should not go here");
         LOG_D(PDCP,"Sending to GTPV1U %d bytes\n", ((pdcp_data_ind_header_t *)(sdu_p->data))->data_size);
         gtpv1u_new_data_req(
               ctxt_pP->module_id, //gtpv1u_data_t *gtpv1u_data_p,
               ctxt_pP->rnti,//rb_id/LTE_maxDRB, TO DO UE ID
               ((pdcp_data_ind_header_t *)(sdu_p->data))->rb_id + 4,
               &(((uint8_t *) sdu_p->data)[sizeof (pdcp_data_ind_header_t)]),
               ((pdcp_data_ind_header_t *)(sdu_p->data))->data_size,
               0);

         list_remove_head (&pdcp_sdu_list);
         free_mem_block (sdu_p, __func__);
         cont = 1;
         pdcp_nb_sdu_sent += 1;
         sdu_p = list_get_head (&pdcp_sdu_list);
         LOG_D(OTG,"After  GTPV1U\n");
         continue; // loop again
      }

#endif /* defined(ENABLE_USE_MME) */
#ifdef PDCP_DEBUG
      LOG_D(PDCP, "PDCP->IP TTI %d INST %d: Preparing %d Bytes of data from rab %d to Nas_mesh\n",
            ctxt_pP->frame, ((pdcp_data_ind_header_t *)(sdu_p->data))->inst,
            ((pdcp_data_ind_header_t *)(sdu_p->data))->data_size, ((pdcp_data_ind_header_t *)(sdu_p->data))->rb_id);
#endif //PDCP_DEBUG
      cont = 0;

//TTN - for D2D (PC5S)
#if (LTE_RRC_VERSION >= MAKE_VERSION(14, 0, 0))
      sidelink_pc5s_element *sl_pc5s_msg_recv = NULL;
      char send_buf[BUFSIZE];
      int rb_id = ((pdcp_data_ind_header_t *)(sdu_p->data))->rb_id;

      if (rb_id >= MAX_NUM_LCID_DATA) { //hardcoded for PC5-Signaling
      //if ((rb_id == 28) | (rb_id == 29) | (rb_id == 30))

#ifdef PDCP_DEBUG
         sl_pc5s_msg_recv = calloc(1, sizeof(sidelink_pc5s_element));
         memcpy((void*)sl_pc5s_msg_recv, (void*)(sdu_p->data+sizeof(pdcp_data_ind_header_t)), sizeof(sidelink_pc5s_element));
         LOG_I(PDCP,"Received PC5S message, header traffic_type: %d)\n", sl_pc5s_msg_recv->pc5s_header.traffic_type);
         LOG_I(PDCP,"Received PC5S message, header rb_id: %d)\n", sl_pc5s_msg_recv->pc5s_header.rb_id);
         LOG_I(PDCP,"Received PC5S message, header data_size: %d)\n", sl_pc5s_msg_recv->pc5s_header.data_size);
         LOG_I(PDCP,"Received PC5S message, header inst: %d)\n", sl_pc5s_msg_recv->pc5s_header.inst);
         LOG_I(PDCP,"Received PC5-S message, sourceL2Id: 0x%08x\n)\n", sl_pc5s_msg_recv->pc5s_header.sourceL2Id);
         LOG_I(PDCP,"Received PC5-S message, destinationL1Id: 0x%08x\n)\n", sl_pc5s_msg_recv->pc5s_header.destinationL2Id);
         free(sl_pc5s_msg_recv);
#endif
         memset(send_buf, 0, BUFSIZE);
         memcpy((void *)send_buf, (void*)(sdu_p->data+sizeof(pdcp_data_ind_header_t)), sizeof(sidelink_pc5s_element));

         int prose_addr_len = sizeof(prose_pdcp_addr);
         int n = sendto(pdcp_pc5_sockfd, (char *)send_buf, sizeof(sidelink_pc5s_element), 0, (struct sockaddr *)&prose_pdcp_addr, prose_addr_len);
         if (n < 0) {
            LOG_E(PDCP, "ERROR: Failed to send to ProSe App\n");
            exit(EXIT_FAILURE);
         }
      }
#endif

      if (!pdcp_output_sdu_bytes_to_write) {
         if (!pdcp_output_header_bytes_to_write) {
            pdcp_output_header_bytes_to_write = sizeof (pdcp_data_ind_header_t);
         }

#ifdef PDCP_USE_RT_FIFO
         bytes_wrote = rtf_put (PDCP2PDCP_USE_RT_FIFO,
               &(((uint8_t *) sdu->data)[sizeof (pdcp_data_ind_header_t) - pdcp_output_header_bytes_to_write]),
               pdcp_output_header_bytes_to_write);

#else
#ifdef PDCP_USE_NETLINK
#ifdef LINUX
         memcpy(NLMSG_DATA(nas_nlh_tx), &(((uint8_t *) sdu_p->data)[sizeof (pdcp_data_ind_header_t) - pdcp_output_header_bytes_to_write]),
               pdcp_output_header_bytes_to_write);
         nas_nlh_tx->nlmsg_len = pdcp_output_header_bytes_to_write;
#endif //LINUX
#endif //PDCP_USE_NETLINK

         bytes_wrote = pdcp_output_header_bytes_to_write;
#endif //PDCP_USE_RT_FIFO

#ifdef PDCP_DEBUG
         LOG_D(PDCP, "Frame %d Sent %d Bytes of header to Nas_mesh\n",
               ctxt_pP->frame,
               bytes_wrote);
#endif //PDCP_DEBUG

         if (bytes_wrote > 0) {
            pdcp_output_header_bytes_to_write = pdcp_output_header_bytes_to_write - bytes_wrote;

            if (!pdcp_output_header_bytes_to_write) { // continue with sdu
               pdcp_output_sdu_bytes_to_write = ((pdcp_data_ind_header_t *) sdu_p->data)->data_size;
               AssertFatal(pdcp_output_sdu_bytes_to_write >= 0, "invalid data_size!");

#ifdef PDCP_USE_RT_FIFO
               bytes_wrote = rtf_put (PDCP2PDCP_USE_RT_FIFO, &(sdu->data[sizeof (pdcp_data_ind_header_t)]), pdcp_output_sdu_bytes_to_write);
#else

#ifdef PDCP_USE_NETLINK
#ifdef LINUX
              // LOG_I(PDCP, "Panos-D: pdcp_fifo_flush_sdus() in PDCP_USE_NETLINK 2 \n");
          memcpy(NLMSG_DATA(nas_nlh_tx)+sizeof(pdcp_data_ind_header_t), &(sdu_p->data[sizeof (pdcp_data_ind_header_t)]), pdcp_output_sdu_bytes_to_write);
          nas_nlh_tx->nlmsg_len += pdcp_output_sdu_bytes_to_write;
          VCD_SIGNAL_DUMPER_DUMP_VARIABLE_BY_NAME( VCD_SIGNAL_DUMPER_VARIABLES_UE_PDCP_FLUSH_SIZE, pdcp_output_sdu_bytes_to_write);
          VCD_SIGNAL_DUMPER_DUMP_FUNCTION_BY_NAME( VCD_SIGNAL_DUMPER_FUNCTIONS_PDCP_FIFO_FLUSH_BUFFER, 1 );
#ifdef UE_NAS_USE_TUN
          ret = write(nas_sock_fd[ctxt_pP->module_id], &(sdu_p->data[sizeof(pdcp_data_ind_header_t)]), pdcp_output_sdu_bytes_to_write);
#else
          ret = sendmsg(nas_sock_fd,&nas_msg_tx,0);
#endif
          VCD_SIGNAL_DUMPER_DUMP_FUNCTION_BY_NAME( VCD_SIGNAL_DUMPER_FUNCTIONS_PDCP_FIFO_FLUSH_BUFFER, 0 );
          VCD_SIGNAL_DUMPER_DUMP_VARIABLE_BY_NAME( VCD_SIGNAL_DUMPER_VARIABLES_UE_PDCP_FLUSH_ERR, ret );

          if (ret<0) {
            LOG_E(PDCP, "[PDCP_FIFOS] sendmsg returns %d (errno: %d)\n", ret, errno);
      	    MSC_LOG_TX_MESSAGE_FAILED(
      	      (ctxt_pP->enb_flag == ENB_FLAG_YES) ? MSC_PDCP_ENB:MSC_PDCP_UE,
      	      (ctxt_pP->enb_flag == ENB_FLAG_YES) ? MSC_IP_ENB:MSC_IP_UE,
      	      NULL,
      	      0,
      	      MSC_AS_TIME_FMT" DATA-IND RNTI %"PRIx16" rb %u size %u",
      	      MSC_AS_TIME_ARGS(ctxt_pP),
      	      ((pdcp_data_ind_header_t *)(sdu_p->data))->rb_id,
      	      ((pdcp_data_ind_header_t *)(sdu_p->data))->data_size);
	    AssertFatal(1==0,"sendmsg failed for nas_sock_fd\n");
            break;
          } else {
        	  MSC_LOG_TX_MESSAGE(
        	    (ctxt_pP->enb_flag == ENB_FLAG_YES) ? MSC_PDCP_ENB:MSC_PDCP_UE,
        	    (ctxt_pP->enb_flag == ENB_FLAG_YES) ? MSC_IP_ENB:MSC_IP_UE,
        	    NULL,
        	    0,
        	    MSC_AS_TIME_FMT" DATA-IND RNTI %"PRIx16" rb %u size %u",
        	    MSC_AS_TIME_ARGS(ctxt_pP),
        	    ((pdcp_data_ind_header_t *)(sdu_p->data))->rb_id,
        	    ((pdcp_data_ind_header_t *)(sdu_p->data))->data_size);
          }

#endif // LINUX
#endif //PDCP_USE_NETLINK
               bytes_wrote= pdcp_output_sdu_bytes_to_write;
#endif // PDCP_USE_RT_FIFO

#ifdef PDCP_DEBUG
               LOG_I(PDCP, "PDCP->IP Frame %d INST %d: Sent %d Bytes of data from rab %d to higher layers\n",
                     ctxt_pP->frame,
                     ((pdcp_data_ind_header_t *)(sdu_p->data))->inst,
                     bytes_wrote,
                     ((pdcp_data_ind_header_t *)(sdu_p->data))->rb_id);
#endif //PDCP_DEBUG

               if (bytes_wrote > 0) {
                  pdcp_output_sdu_bytes_to_write -= bytes_wrote;

                  if (!pdcp_output_sdu_bytes_to_write) { // OK finish with this SDU
                     // LOG_D(PDCP, "rb sent a sdu qos_sap %d\n", sapiP);
                     LOG_D(PDCP,
                           "[FRAME %05d][xxx][PDCP][MOD xx/xx][RB %u][--- PDCP_DATA_IND / %d Bytes --->][IP][INSTANCE %u][RB %u]\n",
                           ctxt_pP->frame,
                           ((pdcp_data_ind_header_t *)(sdu_p->data))->rb_id,
                           ((pdcp_data_ind_header_t *)(sdu_p->data))->data_size,
                           ((pdcp_data_ind_header_t *)(sdu_p->data))->inst,
                           ((pdcp_data_ind_header_t *)(sdu_p->data))->rb_id);

                     list_remove_head (&pdcp_sdu_list);
                     free_mem_block (sdu_p, __func__);

                     cont = 1;
                     pdcp_nb_sdu_sent += 1;
                     sdu_p = list_get_head (&pdcp_sdu_list);
                  } else {
                     LOG_D(PDCP, "1 skip free_mem_block: pdcp_output_sdu_bytes_to_write = %d\n", pdcp_output_sdu_bytes_to_write);
                     AssertFatal(pdcp_output_sdu_bytes_to_write > 0, "pdcp_output_sdu_bytes_to_write cannot be negative!");
                  }
               } else {
                  LOG_W(PDCP, "2: RADIO->IP SEND SDU CONGESTION!\n");
               }
            } else {
               LOG_W(PDCP, "3: RADIO->IP SEND SDU CONGESTION!\n");
            }
         } else {
            LOG_D(PDCP, "4 skip free_mem_block: bytes_wrote = %d\n", bytes_wrote);
         }
      } else {
         // continue writing sdu
#ifdef PDCP_USE_RT_FIFO
         bytes_wrote = rtf_put (PDCP2PDCP_USE_RT_FIFO,
               (uint8_t *) (&(sdu_p->data[sizeof (pdcp_data_ind_header_t) + ((pdcp_data_ind_header_t *) sdu_p->data)->data_size - pdcp_output_sdu_bytes_to_write])),
               pdcp_output_sdu_bytes_to_write);
#else  // PDCP_USE_RT_FIFO
         bytes_wrote = pdcp_output_sdu_bytes_to_write;
#endif  // PDCP_USE_RT_FIFO
         LOG_D(PDCP, "THINH 2 bytes_wrote = %d\n", bytes_wrote);

         if (bytes_wrote > 0) {
            pdcp_output_sdu_bytes_to_write -= bytes_wrote;

            if (!pdcp_output_sdu_bytes_to_write) {     // OK finish with this SDU
               //PRINT_RB_SEND_OUTPUT_SDU ("[PDCP] RADIO->IP SEND SDU\n");
               list_remove_head (&pdcp_sdu_list);
               free_mem_block (sdu_p, __func__);
               cont = 1;
               pdcp_nb_sdu_sent += 1;
               sdu_p = list_get_head (&pdcp_sdu_list);
               // LOG_D(PDCP, "rb sent a sdu from rab\n");
            } else {
               LOG_D(PDCP, "5 skip free_mem_block: pdcp_output_sdu_bytes_to_write = %d\n", pdcp_output_sdu_bytes_to_write);
            }
         } else {
            LOG_D(PDCP, "6 skip free_mem_block: bytes_wrote = %d\n", bytes_wrote);
         }
      }
   }
   VCD_SIGNAL_DUMPER_DUMP_FUNCTION_BY_NAME( VCD_SIGNAL_DUMPER_FUNCTIONS_PDCP_FIFO_FLUSH, 0 );

#ifdef PDCP_USE_RT_FIFO

   if ((pdcp_nb_sdu_sent)) {
      if ((pdcp_2_nas_irq > 0)) {
#ifdef PDCP_DEBUG
         LOG_D(PDCP, "Frame %d : Trigger NAS RX interrupt\n",
               ctxt_pP->frame);
#endif //PDCP_DEBUG
         rt_pend_linux_srq (pdcp_2_nas_irq);

      } else {
         LOG_E(PDCP, "Frame %d: ERROR IF IP STACK WANTED : NOTIF PACKET(S) pdcp_2_nas_irq not initialized : %d\n",
               ctxt_pP->frame,
               pdcp_2_nas_irq);
      }
   }

#endif  //PDCP_USE_RT_FIFO

#ifdef PDCP_SDU_FLUSH_LOCK
   if (pthread_mutex_unlock(&mtex)) exit_fun("PDCP_SDU_FLUSH_LOCK unlock error!");
#endif

   return pdcp_nb_sdu_sent;
}

//-----------------------------------------------------------------------------
int pdcp_fifo_read_input_sdus (const protocol_ctxt_t* const  ctxt_pP)
{
#ifdef UE_NAS_USE_TUN
  protocol_ctxt_t ctxt = *ctxt_pP;
  hash_key_t key = HASHTABLE_NOT_A_KEY_VALUE;
  hashtable_rc_t h_rc;
  pdcp_t* pdcp_p = NULL;
  int len;
  rb_id_t rab_id = DEFAULT_RAB_ID;

  do {
    VCD_SIGNAL_DUMPER_DUMP_FUNCTION_BY_NAME( VCD_SIGNAL_DUMPER_FUNCTIONS_PDCP_FIFO_READ, 1 );
    VCD_SIGNAL_DUMPER_DUMP_FUNCTION_BY_NAME( VCD_SIGNAL_DUMPER_FUNCTIONS_PDCP_FIFO_READ_BUFFER, 1 );
    len = read(nas_sock_fd[ctxt_pP->module_id], &nl_rx_buf, NL_MAX_PAYLOAD);
    VCD_SIGNAL_DUMPER_DUMP_FUNCTION_BY_NAME( VCD_SIGNAL_DUMPER_FUNCTIONS_PDCP_FIFO_READ_BUFFER, 0 );

    if (len<=0) continue;
    LOG_D(PDCP, "PDCP_COLL_KEY_DEFAULT_DRB_VALUE(module_id=%d, rnti=%x, enb_flag=%d)\n",
          ctxt.module_id, ctxt.rnti, ctxt.enb_flag);
    key = PDCP_COLL_KEY_DEFAULT_DRB_VALUE(ctxt.module_id, ctxt.rnti, ctxt.enb_flag);
    h_rc = hashtable_get(pdcp_coll_p, key, (void**)&pdcp_p);
    if (h_rc == HASH_TABLE_OK) {
      LOG_D(PDCP, "[FRAME %5u][UE][NETLINK][IP->PDCP] INST %d: Received socket with length %d on Rab %d \n",
            ctxt.frame, ctxt.instance, len, rab_id);

      LOG_D(PDCP, "[FRAME %5u][UE][IP][INSTANCE %u][RB %u][--- PDCP_DATA_REQ / %d Bytes --->][PDCP][MOD %u][UE %u][RB %u]\n",
            ctxt.frame, ctxt.instance, rab_id, len, ctxt.module_id,
            ctxt.rnti, rab_id);
      MSC_LOG_RX_MESSAGE((ctxt_pP->enb_flag == ENB_FLAG_YES) ? MSC_PDCP_ENB:MSC_PDCP_UE,
                         (ctxt_pP->enb_flag == ENB_FLAG_YES) ? MSC_IP_ENB:MSC_IP_UE,
                         NULL, 0,
                         MSC_AS_TIME_FMT" DATA-REQ inst %u rb %u rab %u size %u",
                         MSC_AS_TIME_ARGS(ctxt_pP),
                         ctxt.instance, rab_id, rab_id, len);

      pdcp_data_req(&ctxt, SRB_FLAG_NO, rab_id, RLC_MUI_UNDEFINED,
                    RLC_SDU_CONFIRM_NO, len, (unsigned char *)nl_rx_buf,
                    PDCP_TRANSMISSION_MODE_DATA
#if (LTE_RRC_VERSION >= MAKE_VERSION(14, 0, 0))
                    , NULL, NULL
#endif
                   );
    } else {
      MSC_LOG_RX_DISCARDED_MESSAGE(
      (ctxt_pP->enb_flag == ENB_FLAG_YES) ? MSC_PDCP_ENB:MSC_PDCP_UE,
      (ctxt_pP->enb_flag == ENB_FLAG_YES) ? MSC_IP_ENB:MSC_IP_UE,
      NULL,
      0,
      MSC_AS_TIME_FMT" DATA-REQ inst %u rb %u rab %u size %u",
      MSC_AS_TIME_ARGS(ctxt_pP),
      ctxt.instance, rab_id, rab_id, len);
      LOG_D(PDCP,
            "[FRAME %5u][UE][IP][INSTANCE %u][RB %u][--- PDCP_DATA_REQ / %d Bytes ---X][PDCP][MOD %u][UE %u][RB %u] NON INSTANCIATED INSTANCE key 0x%"PRIx64", DROPPED\n",
            ctxt.frame, ctxt.instance, rab_id, len, ctxt.module_id,
            ctxt.rnti, rab_id, key);
    }
  } while (len > 0);
  VCD_SIGNAL_DUMPER_DUMP_FUNCTION_BY_NAME( VCD_SIGNAL_DUMPER_FUNCTIONS_PDCP_FIFO_READ, 0 );
  return len;

#else /* UE_NAS_USE_TUN */

#ifdef PDCP_USE_NETLINK
   protocol_ctxt_t                ctxt_cpy = *ctxt_pP;
   protocol_ctxt_t                ctxt;
   hash_key_t                     key       = HASHTABLE_NOT_A_KEY_VALUE;
   hashtable_rc_t                 h_rc;
   struct pdcp_netlink_element_s* data_p    = NULL;
   /* avoid gcc warnings */
   (void)data_p;
   module_id_t                    ue_id     = 0;
   pdcp_t*                        pdcp_p    = NULL;

//TTN for D2D (PC5S)
#if (LTE_RRC_VERSION >= MAKE_VERSION(14, 0, 0))
   int prose_addr_len;
   char send_buf[BUFSIZE], receive_buf[BUFSIZE];
   //int optval;
   int bytes_received;
   sidelink_pc5s_element *sl_pc5s_msg_recv = NULL;
   sidelink_pc5s_element *sl_pc5s_msg_send = NULL;
   //uint32_t sourceL2Id;
   //uint32_t groupL2Id;
   //module_id_t         module_id = 0;
   pc5s_header_t *pc5s_header;
#endif

# if defined(PDCP_USE_NETLINK_QUEUES)
   rb_id_t                        rab_id    = 0;

   pdcp_transmission_mode_t       pdcp_mode = PDCP_TRANSMISSION_MODE_UNKNOWN;


   while (pdcp_netlink_dequeue_element(ctxt_pP, &data_p) != 0) {
      DevAssert(data_p != NULL);
      rab_id = data_p->pdcp_read_header.rb_id % LTE_maxDRB; //Panos: maxDRB
      // ctxt_pP->rnti is NOT_A_RNTI
      ctxt_cpy.rnti = pdcp_module_id_to_rnti[ctxt_cpy.module_id][data_p->pdcp_read_header.inst];
      key = PDCP_COLL_KEY_VALUE(ctxt_pP->module_id, ctxt_cpy.rnti, ctxt_pP->enb_flag, rab_id, SRB_FLAG_NO);
      h_rc = hashtable_get(pdcp_coll_p, key, (void**)&pdcp_p);

      if (h_rc != HASH_TABLE_OK) {
         LOG_W(PDCP, PROTOCOL_CTXT_FMT" Dropped IP PACKET cause no PDCP instanciated\n",
               PROTOCOL_CTXT_ARGS(ctxt_pP));
         free(data_p->data);
         free(data_p);
         data_p = NULL;
         continue;
      }

      CHECK_CTXT_ARGS(&ctxt_cpy);

      AssertFatal (rab_id    < LTE_maxDRB,                       "RB id is too high (%u/%d)!\n", rab_id, LTE_maxDRB);

      if (rab_id != 0) {
         LOG_D(PDCP, "[FRAME %05d][%s][IP][INSTANCE %u][RB %u][--- PDCP_DATA_REQ "
               "/ %d Bytes --->][PDCP][MOD %u][RB %u]\n",
               ctxt_cpy.frame,
               (ctxt_cpy.enb_flag) ? "eNB" : "UE",
                     data_p->pdcp_read_header.inst,
                     data_p->pdcp_read_header.rb_id,
                     data_p->pdcp_read_header.data_size,
                     ctxt_cpy.module_id,
                     rab_id);
#ifdef  OAI_NW_DRIVER_TYPE_ETHERNET

         if ((data_p->pdcp_read_header.traffic_type == TRAFFIC_IPV6_TYPE_MULTICAST) /*TRAFFIC_IPV6_TYPE_MULTICAST */ ||
               (data_p->pdcp_read_header.traffic_type == TRAFFIC_IPV4_TYPE_MULTICAST) /*TRAFFIC_IPV4_TYPE_MULTICAST */ ||
               (data_p->pdcp_read_header.traffic_type == TRAFFIC_IPV4_TYPE_BROADCAST) /*TRAFFIC_IPV4_TYPE_BROADCAST */ ) {
#if (LTE_RRC_VERSION >= MAKE_VERSION(10, 0, 0))
            PDCP_TRANSMISSION_MODE_TRANSPARENT;
#else
            pdcp_mode= PDCP_TRANSMISSION_MODE_DATA;
#endif
         } else if ((data_p->pdcp_read_header.traffic_type == TRAFFIC_IPV6_TYPE_UNICAST) /* TRAFFIC_IPV6_TYPE_UNICAST */ ||
               (data_p->pdcp_read_header.traffic_type == TRAFFIC_IPV4_TYPE_UNICAST) /*TRAFFIC_IPV4_TYPE_UNICAST*/ ) {
            pdcp_mode=  PDCP_TRANSMISSION_MODE_DATA;
         } else {
            pdcp_mode= PDCP_TRANSMISSION_MODE_DATA;
            LOG_W(PDCP,"unknown IP traffic type \n");
         }

#else // OAI_NW_DRIVER_TYPE_ETHERNET NASMESH driver does not curreenlty support multicast traffic
         pdcp_mode = PDCP_TRANSMISSION_MODE_DATA;
#endif
         pdcp_data_req(&ctxt_cpy,
               SRB_FLAG_NO,
               rab_id % LTE_maxDRB,
               RLC_MUI_UNDEFINED,
               RLC_SDU_CONFIRM_NO,
               data_p->pdcp_read_header.data_size,
               data_p->data,
               pdcp_mode
#if (LTE_RRC_VERSION >= MAKE_VERSION(14, 0, 0))
               ,NULL, NULL
#endif
               );
      } else if (ctxt_cpy.enb_flag) {
         /* rb_id = 0, thus interpreated as broadcast and transported as
          * multiple unicast is a broadcast packet, we have to send this
          * packet on all default RABS of all connected UEs
          */
         LOG_D(PDCP, "eNB Try Forcing send on DEFAULT_RAB_ID first_ue_local %u nb_ue_local %u\n", oai_emulation.info.first_ue_local, oai_emulation.info.nb_ue_local);

         for (ue_id = 0; ue_id < NB_UE_INST; ue_id++) {
            if (pdcp_module_id_to_rnti[ctxt_cpy.module_id][ue_id] != NOT_A_RNTI) {
               LOG_D(PDCP, "eNB Try Forcing send on DEFAULT_RAB_ID UE %d\n", ue_id);
               ctxt.module_id     = ctxt_cpy.module_id;
               ctxt.rnti          = ctxt_cpy.pdcp_module_id_to_rnti[ctxt_cpy.module_id][ue_id];
               ctxt.frame         = ctxt_cpy.frame;
               ctxt.enb_flag      = ctxt_cpy.enb_flag;

               pdcp_data_req(
                     &ctxt,
                     SRB_FLAG_NO,
                     DEFAULT_RAB_ID,
                     RLC_MUI_UNDEFINED,
                     RLC_SDU_CONFIRM_NO,
                     data_p->pdcp_read_header.data_size,
                     data_p->data,
                     PDCP_TRANSMISSION_MODE_DATA
#if (LTE_RRC_VERSION >= MAKE_VERSION(14, 0, 0))
                     ,NULL, NULL
#endif
                     );
            }
         }
      } else {
         LOG_D(PDCP, "Forcing send on DEFAULT_RAB_ID\n");
         pdcp_data_req(
               &ctxt_cpy,
               SRB_FLAG_NO,
               DEFAULT_RAB_ID,
               RLC_MUI_UNDEFINED,
               RLC_SDU_CONFIRM_NO,
               data_p->pdcp_read_header.data_size,
               data_p->data,
               PDCP_TRANSMISSION_MODE_DATA
#if (LTE_RRC_VERSION >= MAKE_VERSION(14, 0, 0))
               ,NULL, NULL
#endif
               );
      }

      free(data_p->data);
      free(data_p);
      data_p = NULL;
   }

   return 0;
# else /* PDCP_USE_NETLINK_QUEUES*/
   int              len = 1;
   int  msg_len;
   rb_id_t          rab_id  = 0;
   int rlc_data_req_flag = 3;


//TTN for D2D (PC5S)
#if (LTE_RRC_VERSION >= MAKE_VERSION(14, 0, 0))
   prose_addr_len = sizeof(prose_pdcp_addr);
   // receive a message from ProSe App
   memset(receive_buf, 0, BUFSIZE);
   bytes_received = recvfrom(pdcp_pc5_sockfd, receive_buf, BUFSIZE, 0,
         (struct sockaddr *) &prose_pdcp_addr, (socklen_t *)&prose_addr_len);
   //  if (bytes_received < 0){
   //    LOG_E(RRC, "ERROR: Failed to receive from ProSe App\n");
   //    exit(EXIT_FAILURE);
   // }
   if (bytes_received > 0) {
      pc5s_header = calloc(1, sizeof(pc5s_header_t));
      memcpy((void *)pc5s_header, (void *)receive_buf, sizeof(pc5s_header_t));

      if (pc5s_header->traffic_type == TRAFFIC_PC5S_SESSION_INIT){
         //send reply to ProSe app
         LOG_D(PDCP,"Received a request to open PDCP socket and establish a new PDCP session ... send response to ProSe App \n");
         memset(send_buf, 0, BUFSIZE);
         sl_pc5s_msg_send = calloc(1, sizeof(sidelink_pc5s_element));
         sl_pc5s_msg_send->pc5s_header.traffic_type = TRAFFIC_PC5S_SESSION_INIT;
         sl_pc5s_msg_send->pc5sPrimitive.status = 1;

         memcpy((void *)send_buf, (void *)sl_pc5s_msg_send, sizeof(sidelink_pc5s_element));
         int prose_addr_len = sizeof(prose_pdcp_addr);
         int bytes_sent = sendto(pdcp_pc5_sockfd, (char *)send_buf, sizeof(sidelink_pc5s_element), 0, (struct sockaddr *)&prose_pdcp_addr, prose_addr_len);
         if (bytes_sent < 0) {
            LOG_E(PDCP, "ERROR: Failed to send to ProSe App\n");
            exit(EXIT_FAILURE);
         }
      } else if (pc5s_header->traffic_type == TRAFFIC_PC5S_SIGNALLING) { //if containing PC5-S message -> send to other UE
         LOG_I(PDCP,"Received PC5-S message ... send to the other UE\n");
#ifdef PDCP_DEBUG
         LOG_I(PDCP,"Received PC5-S message, traffic_type: %d)\n", pc5s_header->traffic_type);
         LOG_I(PDCP,"Received PC5-S message, rbid: %d)\n", pc5s_header->rb_id);
         LOG_I(PDCP,"Received PC5-S message, data_size: %d)\n", pc5s_header->data_size);
         LOG_I(PDCP,"Received PC5-S message, inst: %d)\n", pc5s_header->inst);
         LOG_I(PDCP,"Received PC5-S message,sourceL2Id: 0x%08x\n)\n", pc5s_header->sourceL2Id);
         LOG_I(PDCP,"Received PC5-S message,destinationL1Id: 0x%08x\n)\n", pc5s_header->destinationL2Id);

#endif

#ifdef OAI_EMU

         // overwrite function input parameters, because only one netlink socket for all instances
         if (pc5s_header->inst < oai_emulation.info.nb_enb_local) {
            ctxt.frame         = ctxt_cpy.frame;
            ctxt.enb_flag      = ENB_FLAG_YES;
            ctxt.module_id     = pc5s_header.inst  +  oai_emulation.info.first_enb_local;
            ctxt.rnti          = oai_emulation.info.eNB_ue_module_id_to_rnti[ctxt.module_id ][pc5s_header->rb_id / LTE_maxDRB + oai_emulation.info.first_ue_local];
            rab_id    = pc5s_header->rb_id % LTE_maxDRB;
         } else {
            ctxt.frame         = ctxt_cpy.frame;
            ctxt.enb_flag      = ENB_FLAG_NO;
            ctxt.module_id     = pc5s_header->inst - oai_emulation.info.nb_enb_local + oai_emulation.info.first_ue_local;
            ctxt.rnti          = pdcp_UE_UE_module_id_to_rnti[ctxt.module_id];
            rab_id    = pc5s_header->rb_id % LTE_maxDRB;
         }

         CHECK_CTXT_ARGS(&ctxt);
         AssertFatal (rab_id    < LTE_maxDRB,                       "RB id is too high (%u/%d)!\n", rab_id, LTE_maxDRB);
         /*LGpdcp_read_header.inst = (pc5s_header.inst >= oai_emulation.info.nb_enb_local) ? \
                  pc5s_header.inst - oai_emulation.info.nb_enb_local+ NB_eNB_INST + oai_emulation.info.first_ue_local :
                  pc5s_header.inst +  oai_emulation.info.first_enb_local;*/
#else // OAI_EMU
         /* TODO: do we have to reset to 0 or not? not for a scenario with 1 UE at least */
         //          pc5s_header.inst = 0;
         //#warning "TO DO CORRCT VALUES FOR ue mod id, enb mod id"
         ctxt.frame         = ctxt_cpy.frame;
         ctxt.enb_flag      = ctxt_cpy.enb_flag;

         LOG_I(PDCP, "[PDCP] pc5s_header->rb_id = %d\n", pc5s_header->rb_id);

         if (ctxt_cpy.enb_flag) {
            ctxt.module_id = 0;
            rab_id      = pc5s_header->rb_id % LTE_maxDRB;
            ctxt.rnti          = pdcp_eNB_UE_instance_to_rnti[pdcp_eNB_UE_instance_to_rnti_index];
         } else {
            ctxt.module_id = 0;
            rab_id      = pc5s_header->rb_id % LTE_maxDRB;
            ctxt.rnti          = pdcp_UE_UE_module_id_to_rnti[ctxt.module_id];
         }
#endif

         //UE
         if (!ctxt.enb_flag) {
            if (rab_id != 0) {
               if (rab_id == UE_IP_DEFAULT_RAB_ID) {
                  LOG_D(PDCP, "PDCP_COLL_KEY_DEFAULT_DRB_VALUE(module_id=%d, rnti=%x, enb_flag=%d)\n",
                        ctxt.module_id, ctxt.rnti, ctxt.enb_flag);
                  key = PDCP_COLL_KEY_DEFAULT_DRB_VALUE(ctxt.module_id, ctxt.rnti, ctxt.enb_flag);
                  h_rc = hashtable_get(pdcp_coll_p, key, (void**)&pdcp_p);
                  LOG_D(PDCP,"request key %x : (%d,%x,%d,%d)\n",
                        (uint8_t)key,ctxt.module_id, ctxt.rnti, ctxt.enb_flag, rab_id);
               } else {
                  rab_id = rab_id % LTE_maxDRB;
                  LOG_I(PDCP, "PDCP_COLL_KEY_VALUE(module_id=%d, rnti=%x, enb_flag=%d, rab_id=%d, SRB_FLAG=%d)\n",
                        ctxt.module_id, ctxt.rnti, ctxt.enb_flag, rab_id, SRB_FLAG_NO);
                  key = PDCP_COLL_KEY_VALUE(ctxt.module_id, ctxt.rnti, ctxt.enb_flag, rab_id, SRB_FLAG_NO);
                  h_rc = hashtable_get(pdcp_coll_p, key, (void**)&pdcp_p);
                  LOG_I(PDCP,"request key %x : (%d,%x,%d,%d)\n",
                		  (uint8_t)key,ctxt.module_id, ctxt.rnti, ctxt.enb_flag, rab_id);
               }

               if (h_rc == HASH_TABLE_OK) {
                  rab_id = pdcp_p->rb_id;
#ifdef PDCP_DEBUG
                  LOG_D(PDCP, "[FRAME %5u][UE][NETLINK][IP->PDCP] INST %d: Received socket with length %d  on Rab %d \n",
                        ctxt.frame,
                        pc5s_header->inst,
                        bytes_received,
                        pc5s_header->rb_id);

                  LOG_D(PDCP, "[FRAME %5u][UE][IP][INSTANCE %u][RB %u][--- PDCP_DATA_REQ / %d Bytes --->][PDCP][MOD %u][UE %u][RB %u]\n",
                        ctxt.frame,
                        pc5s_header->inst,
                        pc5s_header->rb_id,
                        pc5s_header->data_size,
                        ctxt.module_id,
                        ctxt.rnti,
                        rab_id);
#endif
                  MSC_LOG_RX_MESSAGE(
                        (ctxt_pP->enb_flag == ENB_FLAG_YES) ? MSC_PDCP_ENB:MSC_PDCP_UE,
                              (ctxt_pP->enb_flag == ENB_FLAG_YES) ? MSC_IP_ENB:MSC_IP_UE,
                                    NULL,
                                    0,
                                    MSC_AS_TIME_FMT" DATA-REQ inst %u rb %u rab %u size %u",
                                    MSC_AS_TIME_ARGS(ctxt_pP),
                                    pc5s_header->inst,
                                    pc5s_header->rb_id,
                                    rab_id,
                                    pc5s_header->data_size);

                  /*LOG_I(PDCP, "In pdcp_fifo_read_input_sdus() before calling pdcp_data_req() 1 \n");
                  list_display_memory_head_tail(&pdcp_sdu_list);*/

                  pdcp_data_req(
                        &ctxt,
                        SRB_FLAG_NO,
                        rab_id,
                        RLC_MUI_UNDEFINED,
                        RLC_SDU_CONFIRM_NO,
                        pc5s_header->data_size,
                        (unsigned char *)receive_buf,
                        PDCP_TRANSMISSION_MODE_DATA
#if (LTE_RRC_VERSION >= MAKE_VERSION(14, 0, 0))
                        ,&pc5s_header->sourceL2Id
                        ,&pc5s_header->destinationL2Id
#endif
                        );
                  /*LOG_I(PDCP, "In pdcp_fifo_read_input_sdus() after calling pdcp_data_req 1() \n");
                  list_display_memory_head_tail(&pdcp_sdu_list);*/

               } else {
                  MSC_LOG_RX_DISCARDED_MESSAGE(
                        (ctxt_pP->enb_flag == ENB_FLAG_YES) ? MSC_PDCP_ENB:MSC_PDCP_UE,
                              (ctxt_pP->enb_flag == ENB_FLAG_YES) ? MSC_IP_ENB:MSC_IP_UE,
                                    NULL,
                                    0,
                                    MSC_AS_TIME_FMT" DATA-REQ inst %u rb %u rab %u size %u",
                                    MSC_AS_TIME_ARGS(ctxt_pP),
                                    pc5s_header->inst,
                                    pc5s_header->rb_id,
                                    rab_id,
                                    pc5s_header->data_size);
                  LOG_D(PDCP,
                        "[FRAME %5u][UE][IP][INSTANCE %u][RB %u][--- PDCP_DATA_REQ / %d Bytes ---X][PDCP][MOD %u][UE %u][RB %u] NON INSTANCIATED INSTANCE key 0x%"PRIx64", DROPPED\n",
                        ctxt.frame,
                        pc5s_header->inst,
                        pc5s_header->rb_id,
                        pc5s_header->data_size,
                        ctxt.module_id,
                        ctxt.rnti,
                        rab_id,
                        key);
               }
            }  else { //if (rab_id == 0)
               LOG_D(PDCP, "Forcing send on DEFAULT_RAB_ID\n");
               LOG_D(PDCP, "[FRAME %5u][eNB][IP][INSTANCE %u][RB %u][--- PDCP_DATA_REQ / %d Bytes --->][PDCP][MOD %u][UE %u][RB DEFAULT_RAB_ID %u]\n",
                     ctxt.frame,
                     pc5s_header->inst,
                     pc5s_header->rb_id,
                     pc5s_header->data_size,
                     ctxt.module_id,
                     ctxt.rnti,
                     DEFAULT_RAB_ID);
               MSC_LOG_RX_MESSAGE(
                     (ctxt_pP->enb_flag == ENB_FLAG_YES) ? MSC_PDCP_ENB:MSC_PDCP_UE,
                           (ctxt_pP->enb_flag == ENB_FLAG_YES) ? MSC_IP_ENB:MSC_IP_UE,
                                 NULL,0,
                                 MSC_AS_TIME_FMT" DATA-REQ inst %u rb %u default rab %u size %u",
                                 MSC_AS_TIME_ARGS(ctxt_pP),
                                 pc5s_header->inst,
                                 pc5s_header->rb_id,
                                 DEFAULT_RAB_ID,
                                 pc5s_header->data_size);
               pdcp_data_req (
                     &ctxt,
                     SRB_FLAG_NO,
                     DEFAULT_RAB_ID,
                     RLC_MUI_UNDEFINED,
                     RLC_SDU_CONFIRM_NO,
                     pc5s_header->data_size,
                     (unsigned char *)receive_buf,
                     PDCP_TRANSMISSION_MODE_DATA
#if (LTE_RRC_VERSION >= MAKE_VERSION(14, 0, 0))
                     ,&pc5s_header->sourceL2Id
                     ,&pc5s_header->destinationL2Id
#endif
                     );
            }
         }
          free (sl_pc5s_msg_recv);
          free (sl_pc5s_msg_send);
      }
   }

#endif /*end PC5S*/
   while ((len > 0) && (rlc_data_req_flag !=0))  {
      VCD_SIGNAL_DUMPER_DUMP_FUNCTION_BY_NAME( VCD_SIGNAL_DUMPER_FUNCTIONS_PDCP_FIFO_READ, 1 );
      VCD_SIGNAL_DUMPER_DUMP_FUNCTION_BY_NAME( VCD_SIGNAL_DUMPER_FUNCTIONS_PDCP_FIFO_READ_BUFFER, 1 );
      len = recvmsg(nas_sock_fd, &nas_msg_rx, 0);
      VCD_SIGNAL_DUMPER_DUMP_FUNCTION_BY_NAME( VCD_SIGNAL_DUMPER_FUNCTIONS_PDCP_FIFO_READ_BUFFER, 0 );

      if (len<=0) {
         // nothing in pdcp NAS socket
         //LOG_D(PDCP, "[PDCP][NETLINK] Nothing in socket, length %d \n", len);
      } else {

         msg_len = len;
         for (nas_nlh_rx = (struct nlmsghdr *) nl_rx_buf;
               NLMSG_OK (nas_nlh_rx, msg_len);
               nas_nlh_rx = NLMSG_NEXT (nas_nlh_rx, msg_len)) {

            if (nas_nlh_rx->nlmsg_type == NLMSG_DONE) {
               LOG_D(PDCP, "[PDCP][NETLINK] RX NLMSG_DONE\n");
               //return;
            }

            if (nas_nlh_rx->nlmsg_type == NLMSG_ERROR) {
               LOG_D(PDCP, "[PDCP][NETLINK] RX NLMSG_ERROR\n");
            }

            if (pdcp_read_state_g == 0) {
               if (nas_nlh_rx->nlmsg_len == sizeof (pdcp_data_req_header_t) + sizeof(struct nlmsghdr)) {
                  pdcp_read_state_g = 1;  //get
                  memcpy((void *)&pdcp_read_header_g, (void *)NLMSG_DATA(nas_nlh_rx), sizeof(pdcp_data_req_header_t));
                  LOG_D(PDCP, "[PDCP][NETLINK] RX pdcp_data_req_header_t inst %u, rb_id %u data_size %d, source L2Id 0x%08x, destination L2Id 0x%08x\n",
                        pdcp_read_header_g.inst, pdcp_read_header_g.rb_id, pdcp_read_header_g.data_size,pdcp_read_header_g.sourceL2Id, pdcp_read_header_g.destinationL2Id );
               } else {
                  LOG_E(PDCP, "[PDCP][NETLINK] WRONG size %d should be sizeof (pdcp_data_req_header_t) + sizeof(struct nlmsghdr)\n",
                        nas_nlh_rx->nlmsg_len);
               }
            } else {
               pdcp_read_state_g = 0;
               // print_active_requests()
#ifdef PDCP_DEBUG
               LOG_D(PDCP, "[PDCP][NETLINK] Something in socket, length %zu\n",
                     nas_nlh_rx->nlmsg_len - sizeof(struct nlmsghdr));
#endif

#ifdef OAI_EMU


               // overwrite function input parameters, because only one netlink socket for all instances
               if (pdcp_read_header_g.inst < oai_emulation.info.nb_enb_local) {
                  ctxt.frame         = ctxt_cpy.frame;
                  ctxt.enb_flag      = ENB_FLAG_YES;
                  ctxt.module_id     = pdcp_read_header_g.inst  +  oai_emulation.info.first_enb_local;
                  ctxt.rnti          = oai_emulation.info.eNB_ue_module_id_to_rnti[ctxt.module_id ][pdcp_read_header_g.rb_id / LTE_maxDRB + oai_emulation.info.first_ue_local];
                  rab_id    = pdcp_read_header_g.rb_id % LTE_maxDRB;
               } else {
                  ctxt.frame         = ctxt_cpy.frame;
                  ctxt.enb_flag      = ENB_FLAG_NO;
                  ctxt.module_id     = pdcp_read_header_g.inst - oai_emulation.info.nb_enb_local + oai_emulation.info.first_ue_local;
                  ctxt.rnti          = pdcp_UE_UE_module_id_to_rnti[ctxt.module_id];
                  rab_id    = pdcp_read_header_g.rb_id % LTE_maxDRB;
               }

               CHECK_CTXT_ARGS(&ctxt);
               AssertFatal (rab_id    < LTE_maxDRB,                       "RB id is too high (%u/%d)!\n", rab_id, LTE_maxDRB);
               /*LGpdcp_read_header.inst = (pdcp_read_header_g.inst >= oai_emulation.info.nb_enb_local) ? \
                  pdcp_read_header_g.inst - oai_emulation.info.nb_enb_local+ NB_eNB_INST + oai_emulation.info.first_ue_local :
                  pdcp_read_header_g.inst +  oai_emulation.info.first_enb_local;*/
#else // OAI_EMU
               /* TODO: do we have to reset to 0 or not? not for a scenario with 1 UE at least */
               //          pdcp_read_header_g.inst = 0;
               //#warning "TO DO CORRCT VALUES FOR ue mod id, enb mod id"
               ctxt.frame         = ctxt_cpy.frame;
               ctxt.enb_flag      = ctxt_cpy.enb_flag;

#ifdef PDCP_DEBUG
               LOG_D(PDCP, "[PDCP][NETLINK] pdcp_read_header_g.rb_id = %d, source L2Id = 0x%08x, destination L2Id = 0x%08x \n", pdcp_read_header_g.rb_id, pdcp_read_header_g.sourceL2Id, pdcp_read_header_g.destinationL2Id);
#endif
          if (ctxt_cpy.enb_flag) {
            ctxt.module_id = 0;
            rab_id      = pdcp_read_header_g.rb_id % LTE_maxDRB;
            ctxt.rnti          = pdcp_eNB_UE_instance_to_rnti[pdcp_read_header_g.rb_id / LTE_maxDRB];
          } else {
            if (nfapi_mode == 3) {
#ifdef UESIM_EXPANSION
              ctxt.module_id = inst_pdcp_list[pdcp_read_header_g.inst];
#else
              ctxt.module_id = pdcp_read_header_g.inst;
#endif
            } else {
              ctxt.module_id = 0;
            }
            rab_id      = pdcp_read_header_g.rb_id % LTE_maxDRB;
            ctxt.rnti          = pdcp_UE_UE_module_id_to_rnti[ctxt.module_id];
          }

#endif

          if (ctxt.enb_flag) {
            if (rab_id != 0) {
              rab_id = rab_id % LTE_maxDRB;
              key = PDCP_COLL_KEY_VALUE(ctxt.module_id, ctxt.rnti, ctxt.enb_flag, rab_id, SRB_FLAG_NO);
              h_rc = hashtable_get(pdcp_coll_p, key, (void**)&pdcp_p);

                     if (h_rc == HASH_TABLE_OK) {
#ifdef PDCP_DEBUG
                        LOG_D(PDCP, "[FRAME %5u][eNB][NETLINK][IP->PDCP] INST %d: Received socket with length %d (nlmsg_len = %zu) on Rab %d \n",
                              ctxt.frame,
                              pdcp_read_header_g.inst,
                              len,
                              nas_nlh_rx->nlmsg_len-sizeof(struct nlmsghdr),
                              pdcp_read_header_g.rb_id);
#endif

                        MSC_LOG_RX_MESSAGE(
                              (ctxt_pP->enb_flag == ENB_FLAG_YES) ? MSC_PDCP_ENB:MSC_PDCP_UE,
                                    (ctxt_pP->enb_flag == ENB_FLAG_YES) ? MSC_IP_ENB:MSC_IP_UE,
                                          NULL,
                                          0,
                                          MSC_AS_TIME_FMT" DATA-REQ inst %u rb %u rab %u size %u",
                                          MSC_AS_TIME_ARGS(ctxt_pP),
                                          pdcp_read_header_g.inst,
                                          pdcp_read_header_g.rb_id,
                                          rab_id,
                                          pdcp_read_header_g.data_size);
                        LOG_D(PDCP, "[FRAME %5u][eNB][IP][INSTANCE %u][RB %u][--- PDCP_DATA_REQ / %d Bytes --->][PDCP][MOD %u]UE %u][RB %u]\n",
                              ctxt_cpy.frame,
                              pdcp_read_header_g.inst,
                              pdcp_read_header_g.rb_id,
                              pdcp_read_header_g.data_size,
                              ctxt.module_id,
                              ctxt.rnti,
                              rab_id);

                        pdcp_data_req(&ctxt,
                              SRB_FLAG_NO,
                              rab_id,
                              RLC_MUI_UNDEFINED,
                              RLC_SDU_CONFIRM_NO,
                              pdcp_read_header_g.data_size,
                              (unsigned char *)NLMSG_DATA(nas_nlh_rx),
                              PDCP_TRANSMISSION_MODE_DATA
#if (LTE_RRC_VERSION >= MAKE_VERSION(14, 0, 0))
                              ,NULL, NULL
#endif
                              );
                     } else {
                        LOG_D(PDCP, "[FRAME %5u][eNB][IP][INSTANCE %u][RB %u][--- PDCP_DATA_REQ / %d Bytes ---X][PDCP][MOD %u][UE %u][RB %u] NON INSTANCIATED INSTANCE, DROPPED\n",
                              ctxt.frame,
                              pdcp_read_header_g.inst,
                              pdcp_read_header_g.rb_id,
                              pdcp_read_header_g.data_size,
                              ctxt.module_id,
                              ctxt.rnti,
                              rab_id);
                     }
                  } else  { // rb_id =0, thus interpreated as broadcast and transported as multiple unicast
                     // is a broadcast packet, we have to send this packet on all default RABS of all connected UEs
                     //#warning CODE TO BE REVIEWED, ONLY WORK FOR SIMPLE TOPOLOGY CASES
                     for (ue_id = 0; ue_id < NB_UE_INST; ue_id++) {
                        if (oai_emulation.info.eNB_ue_module_id_to_rnti[ctxt_cpy.module_id][ue_id] != NOT_A_RNTI) {
                           ctxt.rnti = oai_emulation.info.eNB_ue_module_id_to_rnti[ctxt_cpy.module_id][ue_id];
                           LOG_D(PDCP, "[FRAME %5u][eNB][IP][INSTANCE %u][RB %u][--- PDCP_DATA_REQ / %d Bytes --->][PDCP][MOD %u][UE %u][RB DEFAULT_RAB_ID %u]\n",
                                 ctxt.frame,
                                 pdcp_read_header_g.inst,
                                 pdcp_read_header_g.rb_id,
                                 pdcp_read_header_g.data_size,
                                 ctxt.module_id,
                                 ctxt.rnti,
                                 DEFAULT_RAB_ID);
                           pdcp_data_req (
                                 &ctxt,
                                 SRB_FLAG_NO,
                                 DEFAULT_RAB_ID,
                                 RLC_MUI_UNDEFINED,
                                 RLC_SDU_CONFIRM_NO,
                                 pdcp_read_header_g.data_size,
                                 (unsigned char *)NLMSG_DATA(nas_nlh_rx),
                                 PDCP_TRANSMISSION_MODE_DATA
#if (LTE_RRC_VERSION >= MAKE_VERSION(14, 0, 0))
                                ,NULL, NULL
#endif
                                );
                        }
                     }
                  }
               } else { // enb_flag
                  if (rab_id != 0) {
                     if (rab_id == UE_IP_DEFAULT_RAB_ID) {
                        LOG_D(PDCP, "PDCP_COLL_KEY_DEFAULT_DRB_VALUE(module_id=%d, rnti=%x, enb_flag=%d)\n",
                              ctxt.module_id, ctxt.rnti, ctxt.enb_flag);
                        key = PDCP_COLL_KEY_DEFAULT_DRB_VALUE(ctxt.module_id, ctxt.rnti, ctxt.enb_flag);
                        h_rc = hashtable_get(pdcp_coll_p, key, (void**)&pdcp_p);
                        LOG_D(PDCP,"request key %x : (%d,%x,%d,%d)\n",
                        		(uint8_t)key,ctxt.module_id, ctxt.rnti, ctxt.enb_flag, rab_id);
                     } else {
                        rab_id = rab_id % LTE_maxDRB;
                        LOG_D(PDCP, "PDCP_COLL_KEY_VALUE(module_id=%d, rnti=%x, enb_flag=%d, rab_id=%d, SRB_FLAG=%d)\n",
                              ctxt.module_id, ctxt.rnti, ctxt.enb_flag, rab_id, SRB_FLAG_NO);
                        key = PDCP_COLL_KEY_VALUE(ctxt.module_id, ctxt.rnti, ctxt.enb_flag, rab_id, SRB_FLAG_NO);
                        h_rc = hashtable_get(pdcp_coll_p, key, (void**)&pdcp_p);
                        LOG_D(PDCP,"request key %x : (%d,%x,%d,%d)\n",
                        		(uint8_t)key,ctxt.module_id, ctxt.rnti, ctxt.enb_flag, rab_id);
                     }

                     if (h_rc == HASH_TABLE_OK) {
                        rab_id = pdcp_p->rb_id;
#ifdef PDCP_DEBUG
                        LOG_D(PDCP, "[FRAME %5u][UE][NETLINK][IP->PDCP] INST %d: Received socket with length %d (nlmsg_len = %zu) on Rab %d \n",
                              ctxt.frame,
                              pdcp_read_header_g.inst,
                              len,
                              nas_nlh_rx->nlmsg_len-sizeof(struct nlmsghdr),
                              pdcp_read_header_g.rb_id);

                        LOG_D(PDCP, "[FRAME %5u][UE][IP][INSTANCE %u][RB %u][--- PDCP_DATA_REQ / %d Bytes --->][PDCP][MOD %u][UE %u][RB %u]\n",
                              ctxt.frame,
                              pdcp_read_header_g.inst,
                              pdcp_read_header_g.rb_id,
                              pdcp_read_header_g.data_size,
                              ctxt.module_id,
                              ctxt.rnti,
                              rab_id);
#endif
                        MSC_LOG_RX_MESSAGE(
                              (ctxt_pP->enb_flag == ENB_FLAG_YES) ? MSC_PDCP_ENB:MSC_PDCP_UE,
                                    (ctxt_pP->enb_flag == ENB_FLAG_YES) ? MSC_IP_ENB:MSC_IP_UE,
                                          NULL,
                                          0,
                                          MSC_AS_TIME_FMT" DATA-REQ inst %u rb %u rab %u size %u",
                                          MSC_AS_TIME_ARGS(ctxt_pP),
                                          pdcp_read_header_g.inst,
                                          pdcp_read_header_g.rb_id,
                                          rab_id,
                                          pdcp_read_header_g.data_size);
                        if(nfapi_mode == 3){
                        pdcp_data_req(
                              &ctxt,
                              SRB_FLAG_NO,
                              rab_id,
                              RLC_MUI_UNDEFINED,
                              RLC_SDU_CONFIRM_NO,
                              pdcp_read_header_g.data_size,
                              (unsigned char *)NLMSG_DATA(nas_nlh_rx),
                              PDCP_TRANSMISSION_MODE_DATA
#if (LTE_RRC_VERSION >= MAKE_VERSION(14, 0, 0))
                              ,NULL
                              ,NULL
#endif
                              );
                        }else{
                        	//TTN - for traffic from OIP1 (to eNB), sourceL2/DestL2 should be set to NULL
                        	LOG_D(PDCP, "[THINH] source L2 Id: 0x%08x, destL2 0x%08x \n",pdcp_read_header_g.sourceL2Id, pdcp_read_header_g.destinationL2Id);
                        	if (pdcp_read_header_g.inst == 0 ){ //INST == 0 (OIP0)
                        		pdcp_data_req(&ctxt,
                        				SRB_FLAG_NO,
                        				rab_id,
                        				RLC_MUI_UNDEFINED,
                        				RLC_SDU_CONFIRM_NO,
                        				pdcp_read_header_g.data_size,
                        				(unsigned char *)NLMSG_DATA(nas_nlh_rx),
                        				PDCP_TRANSMISSION_MODE_DATA
                        				#if (LTE_RRC_VERSION >= MAKE_VERSION(14, 0, 0))
                        				,&pdcp_read_header_g.sourceL2Id //NULL
                        				,&pdcp_read_header_g.destinationL2Id //NULL
                        				#endif
                        				);
                        	} else {  //INST == 1 (OIP1)
                        		pdcp_data_req(
                        				&ctxt,
                        				SRB_FLAG_NO,
                        				rab_id,
                        				RLC_MUI_UNDEFINED,
                        				RLC_SDU_CONFIRM_NO,
                        				pdcp_read_header_g.data_size,
                        				(unsigned char *)NLMSG_DATA(nas_nlh_rx),
                        				PDCP_TRANSMISSION_MODE_DATA
                        				#if (LTE_RRC_VERSION >= MAKE_VERSION(14, 0, 0))
                        				,NULL
                        				,NULL
                        				#endif
                        				);
                        	}
                        }
                     } else {
                        MSC_LOG_RX_DISCARDED_MESSAGE(
                              (ctxt_pP->enb_flag == ENB_FLAG_YES) ? MSC_PDCP_ENB:MSC_PDCP_UE,
                                    (ctxt_pP->enb_flag == ENB_FLAG_YES) ? MSC_IP_ENB:MSC_IP_UE,
                                          NULL,
                                          0,
                                          MSC_AS_TIME_FMT" DATA-REQ inst %u rb %u rab %u size %u",
                                          MSC_AS_TIME_ARGS(ctxt_pP),
                                          pdcp_read_header_g.inst,
                                          pdcp_read_header_g.rb_id,
                                          rab_id,
                                          pdcp_read_header_g.data_size);
                        LOG_D(PDCP,
                              "[FRAME %5u][UE][IP][INSTANCE %u][RB %u][--- PDCP_DATA_REQ / %d Bytes ---X][PDCP][MOD %u][UE %u][RB %u] NON INSTANCIATED INSTANCE key 0x%"PRIx64", DROPPED\n",
                              ctxt.frame,
                              pdcp_read_header_g.inst,
                              pdcp_read_header_g.rb_id,
                              pdcp_read_header_g.data_size,
                              ctxt.module_id,
                              ctxt.rnti,
                              rab_id,
                              key);
                     }
                  }  else {
                     LOG_D(PDCP, "Forcing send on DEFAULT_RAB_ID\n");
                     LOG_D(PDCP, "[FRAME %5u][eNB][IP][INSTANCE %u][RB %u][--- PDCP_DATA_REQ / %d Bytes --->][PDCP][MOD %u][UE %u][RB DEFAULT_RAB_ID %u]\n",
                           ctxt.frame,
                           pdcp_read_header_g.inst,
                           pdcp_read_header_g.rb_id,
                           pdcp_read_header_g.data_size,
                           ctxt.module_id,
                           ctxt.rnti,
                           DEFAULT_RAB_ID);
                     MSC_LOG_RX_MESSAGE(
                           (ctxt_pP->enb_flag == ENB_FLAG_YES) ? MSC_PDCP_ENB:MSC_PDCP_UE,
                                 (ctxt_pP->enb_flag == ENB_FLAG_YES) ? MSC_IP_ENB:MSC_IP_UE,
                                       NULL,0,
                                       MSC_AS_TIME_FMT" DATA-REQ inst %u rb %u default rab %u size %u",
                                       MSC_AS_TIME_ARGS(ctxt_pP),
                                       pdcp_read_header_g.inst,
                                       pdcp_read_header_g.rb_id,
                                       DEFAULT_RAB_ID,
                                       pdcp_read_header_g.data_size);
                     if(nfapi_mode == 3){
                    	 pdcp_data_req (
                    			 &ctxt,
                    			 SRB_FLAG_NO,
                    			 DEFAULT_RAB_ID,
                    			 RLC_MUI_UNDEFINED,
                    			 RLC_SDU_CONFIRM_NO,
                    			 pdcp_read_header_g.data_size,
                    			 (unsigned char *)NLMSG_DATA(nas_nlh_rx),
                    			 PDCP_TRANSMISSION_MODE_DATA
                    			 #if (LTE_RRC_VERSION >= MAKE_VERSION(14, 0, 0))
                    			 ,NULL
                    			 ,NULL
                    			 #endif
                    			 );
                     }else{
                    	 //TTN - for traffic from OIP1 (to eNB), sourceL2/DestL2 should be set to NULL
                    	 if (pdcp_read_header_g.inst == 0){  //INST == 0 (OIP0)
                    		 LOG_D(PDCP, "[THINH] source L2 Id: 0x%08x, destL2 0x%08x \n",pdcp_read_header_g.sourceL2Id, pdcp_read_header_g.destinationL2Id);
                    		 pdcp_data_req (
                    				 &ctxt,
                    				 SRB_FLAG_NO,
                    				 DEFAULT_RAB_ID,
                    				 RLC_MUI_UNDEFINED,
                    				 RLC_SDU_CONFIRM_NO,
                    				 pdcp_read_header_g.data_size,
                    				 (unsigned char *)NLMSG_DATA(nas_nlh_rx),
                    				 PDCP_TRANSMISSION_MODE_DATA
                    				 #if (LTE_RRC_VERSION >= MAKE_VERSION(14, 0, 0))
                    				 ,&pdcp_read_header_g.sourceL2Id
                    				 ,&pdcp_read_header_g.destinationL2Id
                    				 #endif
                    				 );
                    	 }  else { //INST == 1 (OIP1)
                    		 pdcp_data_req (
                    				 &ctxt,
                    				 SRB_FLAG_NO,
                    				 DEFAULT_RAB_ID,
                    				 RLC_MUI_UNDEFINED,
                    				 RLC_SDU_CONFIRM_NO,
                    				 pdcp_read_header_g.data_size,
                    				 (unsigned char *)NLMSG_DATA(nas_nlh_rx),
                    				 PDCP_TRANSMISSION_MODE_DATA
                    				 #if (LTE_RRC_VERSION >= MAKE_VERSION(14, 0, 0))
                    				 ,NULL
                    				 ,NULL
                    				 #endif
                    				 );
                    	 }
                     }
                  }
               }

            }
         }
      }
      VCD_SIGNAL_DUMPER_DUMP_FUNCTION_BY_NAME( VCD_SIGNAL_DUMPER_FUNCTIONS_PDCP_FIFO_READ, 0 );
   }


   return len;
# endif
#else // neither PDCP_USE_NETLINK nor PDCP_USE_RT_FIFO
   return 0;
#endif // PDCP_USE_NETLINK
#endif /* #else UE_NAS_USE_TUN */
}


void pdcp_fifo_read_input_sdus_from_otg (const protocol_ctxt_t* const  ctxt_pP) {


  module_id_t          dst_id; // dst for otg
  protocol_ctxt_t      ctxt;
  // we need to add conditions to avoid transmitting data when the UE is not RRC connected.
  if ((otg_enabled==1) && (ctxt_pP->enb_flag == ENB_FLAG_YES)) { // generate DL traffic

    PROTOCOL_CTXT_SET_BY_MODULE_ID(
      &ctxt,
      ctxt_pP->module_id,
      ctxt_pP->enb_flag,
      NOT_A_RNTI,
      ctxt_pP->frame,
      ctxt_pP->subframe,
      ctxt_pP->module_id);

    for (dst_id = 0; dst_id<MAX_MOBILES_PER_ENB; dst_id++) {
      ctxt.rnti = oai_emulation.info.eNB_ue_module_id_to_rnti[ctxt.module_id][dst_id];
    }
  }
}

//TTN for D2D (PC5S)
#if (LTE_RRC_VERSION >= MAKE_VERSION(14, 0, 0))

void
pdcp_pc5_socket_init() {
	//pthread_attr_t     attr;
   //struct sched_param sched_param;
   int optval; // flag value for setsockopt
   //int n; // message byte size

   //create PDCP socket
   pdcp_pc5_sockfd = socket(AF_INET, SOCK_DGRAM, 0);
   if (pdcp_pc5_sockfd < 0){
      LOG_E(PDCP,"[pdcp_pc5_socket_init] Error opening socket %d (%d:%s)\n",pdcp_pc5_sockfd,errno, strerror(errno));
      exit(EXIT_FAILURE);
   }

   optval = 1;
   setsockopt(pdcp_pc5_sockfd, SOL_SOCKET, SO_REUSEADDR,
         (const void *)&optval , sizeof(int));

   fcntl(pdcp_pc5_sockfd,F_SETFL,O_NONBLOCK);

   bzero((char *) &pdcp_sin, sizeof(pdcp_sin));
   pdcp_sin.sin_family = AF_INET;
   pdcp_sin.sin_addr.s_addr = htonl(INADDR_ANY);
   pdcp_sin.sin_port = htons(PDCP_SOCKET_PORT_NO);
   // associate the parent socket with a port
   if (bind(pdcp_pc5_sockfd, (struct sockaddr *) &pdcp_sin,
         sizeof(pdcp_sin)) < 0) {
      LOG_E(PDCP,"[pdcp_pc5_socket_init] ERROR: Failed on binding the socket\n");
      exit(1);
   }

}

#endif