Refactor processing of sdap_Config in add_drb (PDCP)

* use get_sdap_Config to process sdap_Config
* move SDAP config logic to the scope where it is relevant
* add SDAP entity direcly in RRC, not from PDCP
* replaced nr_pdcp_add_drbs with single add_drb call: it was no longer
  efficient to keep it in the new logic. The addMod list can be looped directly in RRC.
* add specific function to add bearers from addMod list in E1, NSA, and UE

doc/SW_archi.md

@@ -325,7 +325,7 @@ The PDCP implementation is secured by a general mutex, akin to the design of the
 
 Initialization of the PDCP layer follows a structure similar to that of the RLC layer. The function `nr_pdcp_layer_init()` initializes PDCP, while a second initialization function, `pdcp_module_init()`, must also be invoked.
 
-To manage UE connections, `nr_pdcp_add_srbs()` is employed for adding UE SRBs in PDCP, while `nr_pdcp_remove_UE()` is used for their removal. Similarly, `nr_pdcp_add_drbs()` adds UE DRBs in PDCP, with `nr_pdcp_remove_UE()` handling their removal.
+To manage UE connections, `nr_pdcp_add_srbs()` is employed for adding UE SRBs in PDCP, while `nr_pdcp_remove_UE()` is used for their removal. Similarly, `add_drb()` adds UE DRB in PDCP, with `nr_pdcp_remove_UE()` handling their removal.
 
 ## PDCP Tx flow
 

openair2/LAYER2/nr_pdcp/cucp_cuup_handler.c

@@ -141,6 +141,24 @@ static instance_t get_f1_gtp_instance(void)
   return inst->gtpInst;
 }
 
+/** @brief Add bearer in PDCP/SDAP for 5GC association (SA) */
+static void e1_add_bearers(const int ue_id, const NR_DRB_ToAddModList_t *addMod, const nr_pdcp_entity_security_keys_and_algos_t *sp)
+{
+  for (int i = 0; i < addMod->list.count; i++) {
+    NR_DRB_ToAddMod_t *drb = addMod->list.array[i];
+    DevAssert(drb->cnAssociation);
+    DevAssert(drb->cnAssociation->present != NR_DRB_ToAddMod__cnAssociation_PR_NOTHING);
+    DevAssert(drb->cnAssociation->present == NR_DRB_ToAddMod__cnAssociation_PR_sdap_Config);
+    DevAssert(drb->cnAssociation->choice.sdap_Config);
+    // get SDAP config
+    sdap_config_t sdap = nr_sdap_get_config(GNB_FLAG_YES, drb->cnAssociation->choice.sdap_Config, drb->drb_Identity);
+    // add SDAP entity
+    new_nr_sdap_entity(GNB_FLAG_YES, ue_id, sdap);
+    // add PDCP entity
+    add_drb(GNB_FLAG_YES, ue_id, drb->pdcp_Config, &sdap, sp);
+  }
+}
+
 void e1_bearer_context_setup(const e1ap_bearer_setup_req_t *req)
 {
   bool need_ue_id_mgmt = e1_used();
@@ -208,11 +226,10 @@ void e1_bearer_context_setup(const e1ap_bearer_setup_req_t *req)
     security_parameters.integrity_algorithm = req->secInfo.integrityProtectionAlgorithm;
     memcpy(security_parameters.ciphering_key, req->secInfo.encryptionKey, NR_K_KEY_SIZE);
     memcpy(security_parameters.integrity_key, req->secInfo.integrityProtectionKey, NR_K_KEY_SIZE);
-    nr_pdcp_add_drbs(true, // set this to notify PDCP that his not UE
-                     cu_up_ue_id,
-                     &DRB_configList,
-                     &security_parameters);
+
+    e1_add_bearers(cu_up_ue_id, &DRB_configList, &security_parameters);
     ASN_STRUCT_RESET(asn_DEF_NR_DRB_ToAddModList, &DRB_configList.list);
+
     if (f1inst >= 0) { /* we have F1(-U) */
       teid_t dummy_teid = 0xffff; // we will update later with answer from DU
       in_addr_t dummy_address = {0}; // IPv4, updated later with answer from DU

openair2/LAYER2/nr_pdcp/nr_pdcp_oai_api.c

@@ -576,74 +576,31 @@ void add_srb(int is_gnb,
 }
 
 void add_drb(int is_gnb,
-             ue_id_t UEid,
-             struct NR_DRB_ToAddMod *s,
+             const ue_id_t UEid,
+             const NR_PDCP_Config_t *pdcp,
+             sdap_config_t *sdap,
              const nr_pdcp_entity_security_keys_and_algos_t *security_parameters)
 {
-  nr_pdcp_entity_t *pdcp_drb;
   nr_pdcp_ue_t *ue;
 
-  int drb_id = s->drb_Identity;
-  if (!s->pdcp_Config || !s->pdcp_Config->drb) {
-    LOG_E(PDCP, "DRB field mandatory present at setup. DRB %d not configured.\n", drb_id);
+  if (!pdcp->drb) {
+    LOG_E(PDCP, "Missing PDCP config. DRB %d not configured.\n", sdap->drb_id);
     return;
   }
 
-  struct NR_PDCP_Config__drb *drb = s->pdcp_Config->drb;
+  struct NR_PDCP_Config__drb *drb = pdcp->drb;
   int sn_size_ul = decode_sn_size_ul(*drb->pdcp_SN_SizeUL);
   int sn_size_dl = decode_sn_size_dl(*drb->pdcp_SN_SizeDL);
   int discard_timer = decode_discard_timer(*drb->discardTimer);
 
-  int has_integrity;
-  int has_ciphering;
-
   /* if pdcp_Config->t_Reordering is not present, it means infinity (-1) */
   int t_reordering = -1;
-  if (s->pdcp_Config->t_Reordering != NULL) {
-    t_reordering = decode_t_reordering(*s->pdcp_Config->t_Reordering);
+  if (pdcp->t_Reordering != NULL) {
+    t_reordering = decode_t_reordering(*pdcp->t_Reordering);
   }
 
-  if (drb->integrityProtection != NULL)
-    has_integrity = 1;
-  else
-    has_integrity = 0;
-
-  if (s->pdcp_Config->ext1 != NULL && s->pdcp_Config->ext1->cipheringDisabled != NULL)
-    has_ciphering = 0;
-  else
-    has_ciphering = 1;
-
-  if ((!s->cnAssociation) || s->cnAssociation->present == NR_DRB_ToAddMod__cnAssociation_PR_NOTHING) {
-    LOG_E(PDCP, "fatal, cnAssociation is missing or present is NR_DRB_ToAddMod__cnAssociation_PR_NOTHING\n");
-    exit(-1);
-  }
-
-  int pdusession_id;
-  bool has_sdap_rx = false;
-  bool has_sdap_tx = false;
-  bool is_sdap_DefaultDRB = false;
-  NR_QFI_t *mappedQFIs2Add = NULL;
-  uint8_t mappedQFIs2AddCount=0;
-  if (s->cnAssociation->present == NR_DRB_ToAddMod__cnAssociation_PR_eps_BearerIdentity)
-     pdusession_id = s->cnAssociation->choice.eps_BearerIdentity;
-  else {
-    if (!s->cnAssociation->choice.sdap_Config) {
-      LOG_E(PDCP,"fatal, sdap_Config is null");
-      exit(-1);
-    }
-    pdusession_id = s->cnAssociation->choice.sdap_Config->pdu_Session;
-    has_sdap_rx = is_sdap_rx(is_gnb, s->cnAssociation->choice.sdap_Config);
-    has_sdap_tx = is_sdap_tx(is_gnb, s->cnAssociation->choice.sdap_Config);
-    is_sdap_DefaultDRB = s->cnAssociation->choice.sdap_Config->defaultDRB == true ? 1 : 0;
-    mappedQFIs2Add = (NR_QFI_t*)s->cnAssociation->choice.sdap_Config->mappedQoS_FlowsToAdd->list.array[0]; 
-    mappedQFIs2AddCount = s->cnAssociation->choice.sdap_Config->mappedQoS_FlowsToAdd->list.count;
-    LOG_D(SDAP, "Captured mappedQoS_FlowsToAdd from RRC: %ld \n", *mappedQFIs2Add);
-  }
-  /* TODO(?): accept different UL and DL SN sizes? */
-  if (sn_size_ul != sn_size_dl) {
-    LOG_E(PDCP, "fatal, bad SN sizes, must be same. ul=%d, dl=%d\n", sn_size_ul, sn_size_dl);
-    exit(1);
-  }
+  int has_integrity = (drb->integrityProtection != NULL) ? 1 : 0;
+  int has_ciphering = (pdcp->ext1 != NULL && pdcp->ext1->cipheringDisabled != NULL) ? 0 : 1;
 
   /* get actual ciphering and integrity algorithm based on pdcp_Config */
   nr_pdcp_entity_security_keys_and_algos_t actual_security_parameters = *security_parameters;
@@ -652,29 +609,33 @@ void add_drb(int is_gnb,
 
   nr_pdcp_manager_lock(nr_pdcp_ue_manager);
   ue = nr_pdcp_manager_get_ue(nr_pdcp_ue_manager, UEid);
-  if (nr_pdcp_get_rb(ue, drb_id, false) != NULL) {
-    LOG_W(PDCP, "warning DRB %d already exist for UE ID %ld, do nothing\n", drb_id, UEid);
+  if (nr_pdcp_get_rb(ue, sdap->drb_id, false) != NULL) {
+    LOG_W(PDCP, "warning DRB %d already exist for UE ID %ld, do nothing\n", sdap->drb_id, UEid);
   } else {
-    pdcp_drb = new_nr_pdcp_entity(NR_PDCP_DRB_AM, is_gnb, drb_id, pdusession_id,
-                                  has_sdap_rx, has_sdap_tx, deliver_sdu_drb, ue,
-                                  is_gnb ?
-                                    deliver_pdu_drb_gnb : deliver_pdu_drb_ue,
-                                  ue,
-                                  sn_size_dl, t_reordering, discard_timer,
-                                  &actual_security_parameters);
-    nr_pdcp_ue_add_drb_pdcp_entity(ue, drb_id, pdcp_drb);
+    // code assumption: same SN size for both DL and UL
+    if (sn_size_ul != sn_size_dl) {
+      LOG_E(PDCP, "fatal, bad SN sizes, must be same. ul=%d, dl=%d\n", sn_size_ul, sn_size_dl);
+      exit(1);
+    }
 
-    LOG_I(PDCP, "added drb %d to UE ID %ld\n", drb_id, UEid);
-    /* add new SDAP entity for the PDU session the DRB belongs to */
-    new_nr_sdap_entity(is_gnb,
-                       has_sdap_rx,
-                       has_sdap_tx,
-                       UEid,
-                       pdusession_id,
-                       is_sdap_DefaultDRB,
-                       drb_id,
-                       mappedQFIs2Add,
-                       mappedQFIs2AddCount);
+    // add PDCP entity
+    nr_pdcp_entity_t *pdcp_drb = new_nr_pdcp_entity(NR_PDCP_DRB_AM,
+                                                    is_gnb,
+                                                    sdap->drb_id,
+                                                    sdap->pdusession_id,
+                                                    sdap->sdap_rx,
+                                                    sdap->sdap_tx,
+                                                    deliver_sdu_drb,
+                                                    ue,
+                                                    is_gnb ? deliver_pdu_drb_gnb : deliver_pdu_drb_ue,
+                                                    ue,
+                                                    sn_size_dl,
+                                                    t_reordering,
+                                                    discard_timer,
+                                                    &actual_security_parameters);
+    nr_pdcp_ue_add_drb_pdcp_entity(ue, sdap->drb_id, pdcp_drb);
+
+    LOG_I(PDCP, "Added DRB %d to UE ID %ld\n", sdap->drb_id, UEid);
   }
   nr_pdcp_manager_unlock(nr_pdcp_ue_manager);
 }
@@ -692,22 +653,6 @@ void nr_pdcp_add_srbs(eNB_flag_t enb_flag,
     LOG_W(PDCP, "nr_pdcp_add_srbs() with void list\n");
 }
 
-void nr_pdcp_add_drbs(eNB_flag_t enb_flag,
-                      ue_id_t UEid,
-                      NR_DRB_ToAddModList_t *const drb2add_list,
-                      const nr_pdcp_entity_security_keys_and_algos_t *security_parameters)
-{
-  if (drb2add_list != NULL) {
-    for (int i = 0; i < drb2add_list->list.count; i++) {
-      add_drb(enb_flag,
-              UEid,
-              drb2add_list->list.array[i],
-              security_parameters);
-    }
-  } else
-    LOG_W(PDCP, "nr_pdcp_add_drbs() with void list\n");
-}
-
 uint64_t get_pdcp_optmask(void)
 {
   return pdcp_optmask;

openair2/LAYER2/nr_pdcp/nr_pdcp_oai_api.h

@@ -33,6 +33,7 @@
 #include "nr_pdcp_ue_manager.h"
 struct NR_DRB_ToAddMod;
 struct NR_SRB_ToAddMod;
+struct sdap_configuration_s;
 
 void nr_pdcp_layer_init(void);
 
@@ -42,19 +43,15 @@ bool nr_pdcp_data_ind(const protocol_ctxt_t *const ctxt_pP,
                       const sdu_size_t sdu_buffer_size,
                       uint8_t *const sdu_buffer);
 
-void nr_pdcp_add_drbs(eNB_flag_t enb_flag,
-                      ue_id_t UEid,
-                      NR_DRB_ToAddModList_t *const drb2add_list,
-                      const nr_pdcp_entity_security_keys_and_algos_t *security_parameters);
-
 void nr_pdcp_add_srbs(eNB_flag_t enb_flag,
                       ue_id_t UEid,
                       NR_SRB_ToAddModList_t *const srb2add_list,
                       const nr_pdcp_entity_security_keys_and_algos_t *security_parameters);
 
 void add_drb(int is_gnb,
-             ue_id_t UEid,
-             struct NR_DRB_ToAddMod *s,
+             const ue_id_t UEid,
+             const NR_PDCP_Config_t *pdcp,
+             struct sdap_configuration_s *sdap,
              const nr_pdcp_entity_security_keys_and_algos_t *security_parameters);
 
 void nr_pdcp_remove_UE(ue_id_t ue_id);

openair2/RRC/NR/rrc_gNB_nsa.c

@@ -161,6 +161,28 @@ static NR_RadioBearerConfig_t *get_default_rbconfig(int eps_bearer_id,
   return rbconfig;
 }
 
+static void rrc_nsa_add_drb(const int ue_id,
+                            const NR_DRB_ToAddModList_t *addMod,
+                            const nr_pdcp_entity_security_keys_and_algos_t *sp)
+{
+  for (int i = 0; i < addMod->list.count; i++) {
+    NR_DRB_ToAddMod_t *drb = addMod->list.array[i];
+    DevAssert(drb->cnAssociation);
+    DevAssert(drb->cnAssociation->present != NR_DRB_ToAddMod__cnAssociation_PR_NOTHING);
+    DevAssert(drb->cnAssociation->present == NR_DRB_ToAddMod__cnAssociation_PR_eps_BearerIdentity);
+    // get SDAP config
+    sdap_config_t sdap = {0};
+    // EPC association
+    sdap.pdusession_id = drb->cnAssociation->choice.eps_BearerIdentity;
+    sdap.drb_id = drb->drb_Identity;
+    sdap.defaultDRB = true;
+    // add SDAP entity (terminated at gNB, since it's EPC)
+    new_nr_sdap_entity(GNB_FLAG_YES, ue_id, sdap);
+    // add PDCP entity
+    add_drb(GNB_FLAG_YES, ue_id, drb->pdcp_Config, &sdap, sp);
+  }
+}
+
 /* generate prototypes for the tree management functions (RB_INSERT used in rrc_add_nsa_user) */
 RB_PROTOTYPE(rrc_nr_ue_tree_s, rrc_gNB_ue_context_s, entries,
              rrc_gNB_compare_ue_rnti_id);
@@ -304,10 +326,7 @@ void rrc_add_nsa_user(gNB_RRC_INST *rrc, x2ap_ENDC_sgnb_addition_req_t *m, sctp_
   }
 
   DevAssert(UE->rb_config != NULL);
-  nr_pdcp_add_drbs(GNB_FLAG_YES,
-                   UE->rrc_ue_id,
-                   UE->rb_config->drb_ToAddModList,
-                   &security_parameters);
+  rrc_nsa_add_drb(UE->rrc_ue_id, UE->rb_config->drb_ToAddModList, &security_parameters);
 
   /* assumption: only a single bearer, see above */
   NR_DRB_ToAddModList_t *rb_list = UE->rb_config->drb_ToAddModList;

openair2/RRC/NR_UE/rrc_UE.c

@@ -599,6 +599,31 @@ static void nr_rrc_process_dedicatedNAS_MessageList(NR_UE_RRC_INST_t *rrc, NR_RR
   }
 }
 
+/** @brief Add bearer in PDCP/SDAP for 5GC association (SA) */
+static void rrc_ue_add_bearer(const int ue_id, const NR_DRB_ToAddMod_t *drb, const nr_pdcp_entity_security_keys_and_algos_t *sp)
+{
+  DevAssert(drb->cnAssociation);
+  DevAssert(drb->cnAssociation->present != NR_DRB_ToAddMod__cnAssociation_PR_NOTHING);
+  // get SDAP config
+  sdap_config_t sdap = {0};
+  if (drb->cnAssociation->present == NR_DRB_ToAddMod__cnAssociation_PR_eps_BearerIdentity) {
+    DevAssert(drb->cnAssociation->present == NR_DRB_ToAddMod__cnAssociation_PR_eps_BearerIdentity);
+
+    // EPC association
+    sdap.pdusession_id = drb->cnAssociation->choice.eps_BearerIdentity;
+    sdap.drb_id = drb->drb_Identity;
+    sdap.defaultDRB = true;
+  } else {
+    DevAssert(drb->cnAssociation->present == NR_DRB_ToAddMod__cnAssociation_PR_sdap_Config);
+    DevAssert(drb->cnAssociation->choice.sdap_Config);
+    sdap = nr_sdap_get_config(GNB_FLAG_NO, drb->cnAssociation->choice.sdap_Config, drb->drb_Identity);
+  }
+  // add SDAP entity
+  new_nr_sdap_entity(GNB_FLAG_NO, ue_id, sdap);
+  // add PDCP entity
+  add_drb(GNB_FLAG_NO, ue_id, drb->pdcp_Config, &sdap, sp);
+}
+
 /**
  * @brief add, modify and release SRBs and/or DRBs
  * @ref   3GPP TS 38.331
@@ -706,10 +731,7 @@ static void nr_rrc_ue_process_RadioBearerConfig(NR_UE_RRC_INST_t *ue_rrc, NR_Rad
           nr_reconfigure_sdap_entity(sdap_Config, ue_rrc->ue_id, sdap_Config->pdu_Session, DRB_id);
       } else {
         set_DRB_status(ue_rrc ,DRB_id, RB_ESTABLISHED);
-        add_drb(false,
-                ue_rrc->ue_id,
-                radioBearerConfig->drb_ToAddModList->list.array[cnt],
-                &security_up_parameters);
+        rrc_ue_add_bearer(ue_rrc->ue_id, radioBearerConfig->drb_ToAddModList->list.array[cnt], &security_up_parameters);
       }
     }
   } // drb_ToAddModList //

openair2/SDAP/nr_sdap/nr_sdap_entity.h

@@ -77,7 +77,7 @@ typedef struct qfi2drb_s {
 
 void nr_pdcp_submit_sdap_ctrl_pdu(ue_id_t ue_id, rb_id_t sdap_ctrl_pdu_drb, nr_sdap_ul_hdr_t ctrl_pdu);
 
-typedef struct {
+typedef struct sdap_configuration_s {
   int pdusession_id;
   int drb_id;
   bool sdap_rx;