Removed redundant definition for max SRBs number (used in RRC procedures)

- according to specs, in NR there are 4 SRBs
- in OAI the relevant define is used in the RRC procedures
- this commit harmonizes code by removing redundancy

common/ngran_types.h

@@ -56,5 +56,4 @@ typedef enum { CPtype = 0, UPtype } E1_t;
 #define GTPV1_U_PORT_NUMBER (2152)
 
 typedef enum { non_dynamic, dynamic } fiveQI_type_t;
-#define maxSRBs 4
 #endif

openair2/RRC/NR/nr_rrc_common.h

@@ -28,7 +28,7 @@
 
 #define NR_RRC_HEADER_SIZE_MAX 64
 #define NR_RRC_BUFFER_SIZE_MAX 1024
-#define NR_NUM_SRB 4
+#define NR_NUM_SRB 4 /* Number of Signalling Radio Bearers according to clause 4.2.2 of 3GPP TS 38.331 */
 #define NR_K_KEY_SIZE 16 /* K keys have 128 bits length */
 
 typedef struct {

openair2/RRC/NR/nr_rrc_defs.h

@@ -241,7 +241,7 @@ typedef struct gNB_RRC_UE_s {
   drb_t                              established_drbs[MAX_DRBS_PER_UE];
   NR_DRB_ToReleaseList_t            *DRB_ReleaseList;
 
-  NR_SRB_INFO_TABLE_ENTRY Srb[maxSRBs]; // 3gpp max is 3 SRBs, number 1..3, we waste the entry 0 for code simplicity
+  NR_SRB_INFO_TABLE_ENTRY Srb[NR_NUM_SRB];
   NR_MeasConfig_t                   *measConfig;
   NR_HANDOVER_INFO                  *handover_info;
   NR_MeasResults_t                  *measResults;

openair2/RRC/NR/rrc_gNB.c

@@ -348,7 +348,7 @@ static NR_SRB_ToAddModList_t *createSRBlist(gNB_RRC_UE_t *ue, bool reestablish)
     return NULL;
   }
   NR_SRB_ToAddModList_t *list = CALLOC(sizeof(*list), 1);
-  for (int i = 0; i < maxSRBs; i++)
+  for (int i = 0; i < NR_NUM_SRB; i++)
     if (ue->Srb[i].Active) {
       asn1cSequenceAdd(list->list, NR_SRB_ToAddMod_t, srb);
       srb->srb_Identity = i;
@@ -918,7 +918,8 @@ static void rrc_gNB_generate_RRCReestablishment(rrc_gNB_ue_context_t *ue_context
   uint8_t security_mode =
       enable_ciphering ? ue_p->ciphering_algorithm | (ue_p->integrity_algorithm << 4) : 0 | (ue_p->integrity_algorithm << 4);
 
-  for (int srb_id = 1; srb_id < maxSRBs; srb_id++) {
+  /* SRBs */
+  for (int srb_id = 1; srb_id < NR_NUM_SRB; srb_id++) {
     if (ue_p->Srb[srb_id].Active) {
       nr_pdcp_config_set_security(ue_p->rrc_ue_id, srb_id, security_mode, kRRCenc, kRRCint, kUPenc);
       // TODO: should send E1 UE Bearer Modification with PDCP Reestablishment flag