Paging (F1AP): wire paging through mac_rrc_dl and use F1AP free/decoding lib on CU/DU

Introduce paging_transfer in the mac_rrc_dl interface so the CU can pass
paging to the DU (F1 or direct). Use the F1AP paging lib on both CU and DU
for decode/free and to avoid leaking the message after send.

- Add f1_paging_transfer_func_t and paging_transfer to nr_mac_rrc_dl_if_s
  (mac_rrc_dl.h, nr_rrc_defs.h).
- F1AP path: paging_f1ap() allocates F1AP_PAGING, copies with cp_f1ap_paging(),
  sends via ITTI to TASK_CU_F1. Direct path: f1_paging_transfer_direct() stub
- CU task: call free_f1ap_paging() after CU_send_Paging() to release the message.
- DU: DU_handle_Paging() uses decode_f1ap_paging()/free_f1ap_paging() from lib,
  returns on decode failure; remove inline ASN.1 IE parsing.
- cleanup outdated header comments in header files
- Left a TODO not in DU code to build PCCH (in F1 and direct paths)

openair2/F1AP/f1ap_cu_task.c

@@ -38,6 +38,7 @@
 #include "lib/f1ap_interface_management.h"
 #include "lib/f1ap_ue_context.h"
 #include "f1ap_cu_paging.h"
+#include "lib/f1ap_paging.h"
 #include "f1ap_cu_task.h"
 #include "openair2/RRC/NR/nr_rrc_defs.h"
 #include <openair3/ocp-gtpu/gtp_itf.h>
@@ -204,6 +205,7 @@ void *F1AP_CU_task(void *arg) {
 
       case F1AP_PAGING:
         CU_send_Paging(assoc_id, &F1AP_PAGING(received_msg));
+        free_f1ap_paging(&F1AP_PAGING(received_msg));
         break;
 
       case F1AP_UE_CONTEXT_MODIFICATION_CONFIRM:

openair2/F1AP/f1ap_du_paging.c

@@ -19,75 +19,37 @@
  *      contact@openairinterface.org
  */
 
-/*! \file f1ap_du_interface_management.h
- * \brief f1ap interface management for DU
- * \author EURECOM/NTUST
- * \date 2018
- * \version 0.1
- * \company Eurecom
- * \email: navid.nikaein@eurecom.fr, bing-kai.hong@eurecom.fr
- * \note
- * \warning
- */
 #include "f1ap_common.h"
 #include "f1ap_du_paging.h"
+#include "lib/f1ap_paging.h"
 #include "conversions.h"
 #include "oai_asn1.h"
 #include "openair2/RRC/LTE/rrc_proto.h"
 
+/* @brief Handle F1AP Paging message at DU */
 int DU_handle_Paging(instance_t instance, sctp_assoc_t assoc_id, uint32_t stream, F1AP_F1AP_PDU_t *pdu)
 {
-  F1AP_Paging_t *paging;
-  F1AP_PagingIEs_t *ie;
-  long tmsi;
-  uint8_t pagingdrx;
-  uint8_t  *fiveg_tmsi_buf = NULL;
+  f1ap_paging_t decoded = {0};
 
   DevAssert(pdu);
+  (void)instance;
+  (void)assoc_id;
+  (void)stream;
 
-  if ( LOG_DEBUGFLAG(DEBUG_ASN1) ) {
+  if (LOG_DEBUGFLAG(DEBUG_ASN1)) {
     xer_fprint(stdout, &asn_DEF_F1AP_F1AP_PDU, pdu);
   }
 
-  paging = &pdu->choice.initiatingMessage->value.choice.Paging;
-  // get UEIdentityIndexValue
-  F1AP_FIND_PROTOCOLIE_BY_ID(F1AP_PagingIEs_t, ie, paging,
-                             F1AP_ProtocolIE_ID_id_UEIdentityIndexValue, true);
-
-  LOG_D(F1AP, "indexLength10 %d\n", BIT_STRING_to_uint32(&ie->value.choice.UEIdentityIndexValue.choice.indexLength10));
-
-  // get PagingIdentity
-  F1AP_FIND_PROTOCOLIE_BY_ID(F1AP_PagingIEs_t, ie, paging,
-                             F1AP_ProtocolIE_ID_id_PagingIdentity, true);
-
-  if(ie != NULL){
-    fiveg_tmsi_buf = ie->value.choice.PagingIdentity.choice.cNUEPagingIdentity->choice.fiveG_S_TMSI.buf;
-
-    tmsi = ((long)fiveg_tmsi_buf[0] << 40) +
-           ((long)fiveg_tmsi_buf[1] << 32) +
-           (fiveg_tmsi_buf[2] << 24) +
-           (fiveg_tmsi_buf[3] << 16) +
-           (fiveg_tmsi_buf[4] << 8) +
-           fiveg_tmsi_buf[5];
-
-    LOG_D(F1AP, "tmsi %ld\n", tmsi);
+  if (!decode_f1ap_paging(&decoded, pdu)) {
+    LOG_E(F1AP, "Failed to decode F1AP Paging\n");
+    return -1;
   }
 
-  // get PagingDRX
-  F1AP_FIND_PROTOCOLIE_BY_ID(F1AP_PagingIEs_t, ie, paging,
-                             F1AP_ProtocolIE_ID_id_PagingDRX, true);
-
-  if(ie != NULL) {
-    pagingdrx = (uint8_t)ie->value.choice.PagingDRX;
-  }
-
-  LOG_D(F1AP, "pagingdrx %u\n", pagingdrx);
-
-  // get PagingCell_List
-  F1AP_FIND_PROTOCOLIE_BY_ID(F1AP_PagingIEs_t, ie, paging,
-                             F1AP_ProtocolIE_ID_id_PagingCell_List, true);
-
-  AssertFatal(false, "not implemented\n");
+  /** @todo Build PCCH-Message (Paging) at DU per TS 38.331 §5.3.2; apply
+   *  RRC padding per §8.5; deliver as RLC SDU per §8.2. For each
+   *  cell in Paging Cell List that belongs to this DU, queue for MAC; MAC schedules
+   *  at PF/PO per TS 38.304 §7. */
 
+  free_f1ap_paging(&decoded);
   return 0;
 }

openair2/F1AP/f1ap_du_paging.h

@@ -19,20 +19,10 @@
  *      contact@openairinterface.org
  */
 
-/*! \file f1ap_du_interface_management.h
- * \brief f1ap interface management for DU
- * \author EURECOM/NTUST
- * \date 2018
- * \version 0.1
- * \company Eurecom
- * \email: navid.nikaein@eurecom.fr, bing-kai.hong@eurecom.fr
- * \note
- * \warning
- */
-
 #ifndef F1AP_DU_PAGING_H_
 #define F1AP_DU_PAGING_H_
 
+/* Paging (gNB-CU initiated) */
 int DU_handle_Paging(instance_t instance, sctp_assoc_t assoc_id, uint32_t stream, F1AP_F1AP_PDU_t *pdu);
 
 #endif /* F1AP_DU_PAGING_H_ */