Refactor SDAP UL: QoS flow to DRB Mapping configuration and end-marker control PDU mapping

The function nr_sdap_ue_qfi2drb_config should do UL QoS flow to DRB mapping configuration
for a SDAP entity has already been established according to TS 37.324, 5.3 QoS flow to
DRB Mapping, 5.3.1 Configuration Procedures. It should handle both mapping rules to add and to remove.

To this purpose:

* Simplify function signature by passing the sdap config.
* Improve readability of the function.
* Move handling of sdap.mappedQFIs2ReleaseCount (in nr_reconfigure_sdap_entity)
  inside the function.
* Simplify end-marker control PDU mapping function by removing unused
  DRB ID input parameter (the function is fetching the DRB ID based on the input
  map type)
* use int instead of legacy rb_id_t
* limit scope of functions whenever necessary

openair2/SDAP/nr_sdap/nr_sdap_entity.c

@@ -281,7 +281,7 @@ static void nr_sdap_rx_entity(nr_sdap_entity_t *entity,
          */
         if(!entity->qfi2drb_table[sdap_hdr->QFI].drb_id && entity->default_drb){
           nr_sdap_ul_hdr_t sdap_ctrl_pdu = entity->sdap_construct_ctrl_pdu(sdap_hdr->QFI);
-          rb_id_t sdap_ctrl_pdu_drb = entity->sdap_map_ctrl_pdu(entity, pdcp_entity, SDAP_CTRL_PDU_MAP_DEF_DRB, sdap_hdr->QFI);
+          int sdap_ctrl_pdu_drb = entity->sdap_map_ctrl_pdu(entity, SDAP_CTRL_PDU_MAP_DEF_DRB, sdap_hdr->QFI);
           entity->sdap_submit_ctrl_pdu(ue_id, sdap_ctrl_pdu_drb, sdap_ctrl_pdu);
         }
 
@@ -296,7 +296,7 @@ static void nr_sdap_rx_entity(nr_sdap_entity_t *entity,
          */
         if (pdcp_entity != entity->qfi2drb_table[sdap_hdr->QFI].drb_id) {
           nr_sdap_ul_hdr_t sdap_ctrl_pdu = entity->sdap_construct_ctrl_pdu(sdap_hdr->QFI);
-          rb_id_t sdap_ctrl_pdu_drb = entity->sdap_map_ctrl_pdu(entity, pdcp_entity, SDAP_CTRL_PDU_MAP_RULE_DRB, sdap_hdr->QFI);
+          int sdap_ctrl_pdu_drb = entity->sdap_map_ctrl_pdu(entity, SDAP_CTRL_PDU_MAP_RULE_DRB, sdap_hdr->QFI);
           entity->sdap_submit_ctrl_pdu(ue_id, sdap_ctrl_pdu_drb, sdap_ctrl_pdu);
         }
 
@@ -397,15 +397,16 @@ nr_sdap_ul_hdr_t nr_sdap_construct_ctrl_pdu(uint8_t qfi){
   return sdap_end_marker_hdr;
 }
 
-rb_id_t nr_sdap_map_ctrl_pdu(nr_sdap_entity_t *entity, rb_id_t pdcp_entity, int map_type, uint8_t dl_qfi){
-  rb_id_t drb_of_endmarker = 0;
+int nr_sdap_map_ctrl_pdu(nr_sdap_entity_t *entity, int map_type, uint8_t dl_qfi)
+{
+  int drb_of_endmarker = 0;
   if(map_type == SDAP_CTRL_PDU_MAP_DEF_DRB){
     drb_of_endmarker = entity->default_drb;
-    LOG_D(SDAP, "Mapping Control PDU QFI: %u to Default DRB: %ld\n", dl_qfi, drb_of_endmarker);
+    LOG_D(SDAP, "Mapping Control PDU QFI: %u to Default DRB: %d\n", dl_qfi, drb_of_endmarker);
   }
   if(map_type == SDAP_CTRL_PDU_MAP_RULE_DRB){
     drb_of_endmarker = entity->qfi2drb_map(entity, dl_qfi);
-    LOG_D(SDAP, "Mapping Control PDU QFI: %u to DRB: %ld\n", dl_qfi, drb_of_endmarker);
+    LOG_D(SDAP, "Mapping Control PDU QFI: %u to DRB: %d\n", dl_qfi, drb_of_endmarker);
   }
   return drb_of_endmarker;
 }
@@ -421,39 +422,40 @@ void nr_sdap_submit_ctrl_pdu(ue_id_t ue_id, rb_id_t sdap_ctrl_pdu_drb, nr_sdap_u
   }
 }
 
-/**
- * @brief UL QoS flow to DRB mapping configuration for an existing SDAP entity
- *        according to TS 37.324, 5.3 QoS flow to DRB Mapping, clause 5.3.1 Configuration Procedures
- */
-static void nr_sdap_ue_qfi2drb_config(nr_sdap_entity_t *existing_sdap_entity,
-                                      rb_id_t pdcp_entity,
-                                      ue_id_t ue_id,
-                                      NR_QFI_t *mapped_qfi_2_add,
-                                      uint8_t mappedQFIs2AddCount,
-                                      uint8_t drb_identity,
-                                      bool has_sdap_rx,
-                                      bool has_sdap_tx)
+/** @brief UL QoS flow to DRB mapping configuration for a SDAP entity has already been established
+ *         according to TS 37.324, 5.3 QoS flow to DRB Mapping, 5.3.1 Configuration Procedures.
+ *         The function handles both UL QoS Flows mapping rules to add and to remove. */
+static void nr_sdap_ue_qfi2drb_config(nr_sdap_entity_t *entity, const ue_id_t ue_id, const sdap_config_t sdap)
 {
-  LOG_D(SDAP, "RRC Configuring SDAP Entity\n");
-  for(int i = 0; i < mappedQFIs2AddCount; i++){
-    uint8_t qfi = mapped_qfi_2_add[i];
-    /* a default DRB exists and there is no QFI to DRB mapping rule for the QFI */
-    if (existing_sdap_entity->default_drb && existing_sdap_entity->qfi2drb_table[qfi].drb_id == SDAP_NO_MAPPING_RULE) {
-      nr_sdap_ul_hdr_t sdap_ctrl_pdu = existing_sdap_entity->sdap_construct_ctrl_pdu(qfi);
-      rb_id_t sdap_ctrl_pdu_drb =
-          existing_sdap_entity->sdap_map_ctrl_pdu(existing_sdap_entity, pdcp_entity, SDAP_CTRL_PDU_MAP_DEF_DRB, qfi);
-      existing_sdap_entity->sdap_submit_ctrl_pdu(ue_id, sdap_ctrl_pdu_drb, sdap_ctrl_pdu);
-    }
-    /* the stored UL QFI to DRB mapping rule is different from the configured one and has UL SDAP header*/
-    if (existing_sdap_entity->qfi2drb_table[qfi].drb_id != drb_identity && existing_sdap_entity->qfi2drb_table[qfi].has_sdap_tx) {
-      nr_sdap_ul_hdr_t sdap_ctrl_pdu = existing_sdap_entity->sdap_construct_ctrl_pdu(qfi);
-      rb_id_t sdap_ctrl_pdu_drb =
-          existing_sdap_entity->sdap_map_ctrl_pdu(existing_sdap_entity, pdcp_entity, SDAP_CTRL_PDU_MAP_RULE_DRB, qfi);
-      existing_sdap_entity->sdap_submit_ctrl_pdu(ue_id, sdap_ctrl_pdu_drb, sdap_ctrl_pdu);
-    }
-    /* update QFI to DRB mapping rules */
+  // handle QFIs to DRB mapping rule to add
+  for (int i = 0; i < sdap.mappedQFIs2AddCount; i++) {
+    uint8_t qfi = sdap.mappedQFIs2Add[i];
+    /* a default DRB exists and there is no stored QFI to DRB mapping rule for the QFI */
+    if (entity->default_drb && entity->qfi2drb_table[qfi].drb_id == SDAP_NO_MAPPING_RULE) {
+      // construct an end-marker control PDU (6.2.3 TS 37.324)
+      nr_sdap_ul_hdr_t sdap_ctrl_pdu = entity->sdap_construct_ctrl_pdu(qfi);
+      // map the end-marker control PDU to the default DRB
+      int sdap_ctrl_pdu_drb = entity->sdap_map_ctrl_pdu(entity, SDAP_CTRL_PDU_MAP_DEF_DRB, qfi);
+      // submit the end-marker control PDU to the lower layers
+      entity->sdap_submit_ctrl_pdu(ue_id, sdap_ctrl_pdu_drb, sdap_ctrl_pdu);
+    }
+    /* the stored UL QFI to DRB mapping rule is different from the configured one and has UL SDAP header */
+    if (entity->qfi2drb_table[qfi].drb_id != sdap.drb_id && entity->qfi2drb_table[qfi].has_sdap_tx) {
+      // construct an end-marker control PDU (6.2.3 TS 37.324)
+      nr_sdap_ul_hdr_t sdap_ctrl_pdu = entity->sdap_construct_ctrl_pdu(qfi);
+      // map the end-marker control PDU to the DRB according to the stored QoS flow to DRB mapping rule
+      int sdap_ctrl_pdu_drb = entity->sdap_map_ctrl_pdu(entity, SDAP_CTRL_PDU_MAP_RULE_DRB, qfi);
+      // submit the end-marker control PDU to the lower layers
+      entity->sdap_submit_ctrl_pdu(ue_id, sdap_ctrl_pdu_drb, sdap_ctrl_pdu);
+    }
+    // store QFI to DRB mapping rules
     LOG_D(SDAP, "Storing the configured QoS flow to DRB mapping rule\n");
-    existing_sdap_entity->qfi2drb_map_update(existing_sdap_entity, qfi, drb_identity, has_sdap_rx, has_sdap_tx);
+    entity->qfi2drb_map_update(entity, qfi, sdap.drb_id, sdap.sdap_rx, sdap.sdap_tx);
+  }
+
+  // handle QFIs to DRB mapping rule to release
+  for (int i = 0; i < sdap.mappedQFIs2ReleaseCount; i++) {
+    entity->qfi2drb_map_delete(entity, sdap.mappedQFIs2Release[i]);
   }
 }
 
@@ -478,14 +480,7 @@ nr_sdap_entity_t *new_nr_sdap_entity(const int is_gnb, const ue_id_t ue_id, cons
   if (sdap_entity) {
     LOG_E(SDAP, "SDAP Entity for UE already exists with RNTI/UE ID: %lu and PDU SESSION ID: %d\n", ue_id, sdap.pdusession_id);
     if (!is_gnb) {
-      nr_sdap_ue_qfi2drb_config(sdap_entity,
-                                sdap_entity->default_drb,
-                                ue_id,
-                                sdap.mappedQFIs2Add,
-                                sdap.mappedQFIs2AddCount,
-                                sdap.drb_id,
-                                sdap.sdap_rx,
-                                sdap.sdap_tx);
+      nr_sdap_ue_qfi2drb_config(sdap_entity, ue_id, sdap);
     } else {
       // store QFI to DRB mapping rules
       for (int i = 0; i < sdap.mappedQFIs2AddCount; i++) {
@@ -708,20 +703,8 @@ void nr_reconfigure_sdap_entity(NR_SDAP_Config_t *sdap_config, ue_id_t ue_id, in
               ue_id,
               pdusession_id);
   /* QFI to DRB mapping */
-  sdap_config_t sdap = get_sdap_Config(is_gnb, sdap_config, drb_id);
-  nr_sdap_ue_qfi2drb_config(sdap_entity,
-                            sdap_entity->default_drb,
-                            ue_id,
-                            sdap.mappedQFIs2Add,
-                            sdap.mappedQFIs2AddCount,
-                            drb_id,
-                            sdap.sdap_rx,
-                            sdap.sdap_tx);
-  /* handle QFIs to DRB mapping rule to release */
-  for (int i = 0; i < sdap.mappedQFIs2ReleaseCount; i++) {
-    uint8_t qfi = sdap.mappedQFIs2Release[i];
-    sdap_entity->qfi2drb_map_delete(sdap_entity, qfi);
-  }
+  sdap_config_t sdap = nr_sdap_get_config(is_gnb, sdap_config, drb_id);
+  nr_sdap_ue_qfi2drb_config(sdap_entity, ue_id, sdap);
 }
 
 void set_qfi(uint8_t qfi, uint8_t pduid, ue_id_t ue_id)

openair2/SDAP/nr_sdap/nr_sdap_entity.h

@@ -108,7 +108,7 @@ typedef struct nr_sdap_entity_s {
   int (*qfi2drb_map)(struct nr_sdap_entity_s *entity, uint8_t qfi);
 
   nr_sdap_ul_hdr_t (*sdap_construct_ctrl_pdu)(uint8_t qfi);
-  rb_id_t (*sdap_map_ctrl_pdu)(struct nr_sdap_entity_s *entity, rb_id_t pdcp_entity, int map_type, uint8_t dl_qfi);
+  int (*sdap_map_ctrl_pdu)(struct nr_sdap_entity_s *entity, int map_type, uint8_t dl_qfi);
   void (*sdap_submit_ctrl_pdu)(ue_id_t ue_id, rb_id_t sdap_ctrl_pdu_drb, nr_sdap_ul_hdr_t ctrl_pdu);
 
   bool (*tx_entity)(struct nr_sdap_entity_s *entity,
@@ -156,7 +156,7 @@ nr_sdap_ul_hdr_t nr_sdap_construct_ctrl_pdu(uint8_t qfi);
  * 1.) default DRB or 
  * 2.) DRB according to the stored QoS flow to DRB mapping rule
  */
-rb_id_t nr_sdap_map_ctrl_pdu(nr_sdap_entity_t *entity, rb_id_t pdcp_entity, int map_type, uint8_t dl_qfi);
+int nr_sdap_map_ctrl_pdu(nr_sdap_entity_t *entity, int map_type, uint8_t dl_qfi);
 
 /*
  * TS 37.324 5.3 QoS flow to DRB Mapping