cu_cp,f1ap: add function to return 5g-s-tmsi as number

Author: FabianEckermann

include/srsran/cu_cp/cu_cp_types.h

@@ -150,6 +150,8 @@ struct cu_cp_five_g_s_tmsi {
     return (five_g_s_tmsi.value().to_uint64() & 0xffffffff);
   };
 
+  uint64_t to_number() const { return five_g_s_tmsi->to_uint64(); }
+
   std::optional<bounded_bitset<48>> five_g_s_tmsi;
 };
 

lib/f1ap/cu_cp/f1ap_asn1_converters.h

@@ -557,14 +557,6 @@ f1ap_rrc_recfg_complete_ind_to_asn1(const f1ap_rrc_recfg_complete_ind& rrc_recfg
   return asn1_rrc_recfg_complete_ind;
 }
 
-/// \brief Calculate the 5G-S-TMSI from the common type 5G-S-TMSI struct.
-inline uint64_t five_g_s_tmsi_struct_to_number(const cu_cp_five_g_s_tmsi& five_g_s_tmsi)
-{
-  // 5G-S-TMSI is a 48 bit string consisting of <aMFSetId (10 bit)><aMFPointer (6 bit)><5G-TMSI (32 bit)>
-  return ((uint64_t)five_g_s_tmsi.get_amf_set_id() << 38) + ((uint64_t)five_g_s_tmsi.get_amf_pointer() << 32) +
-         five_g_s_tmsi.get_five_g_tmsi();
-}
-
 /// \brief Convert F1AP ASN.1 to \c cu_cp_tx_bw.
 /// \param[in] asn1_tx_bw The ASN.1 type tx bw.
 /// \return The common type tx bw.

lib/f1ap/cu_cp/f1ap_asn1_helpers.h

@@ -468,7 +468,7 @@ inline void fill_f1ap_ue_context_modification_response(f1ap_ue_context_modificat
 inline void fill_asn1_paging_message(asn1::f1ap::paging_s& asn1_paging, const cu_cp_paging_message& paging)
 {
   // Add ue id idx value
-  uint64_t five_g_s_tmsi = five_g_s_tmsi_struct_to_number(paging.ue_paging_id);
+  uint64_t five_g_s_tmsi = paging.ue_paging_id.to_number();
 
   // UE Identity Index value is defined as: UE_ID 5G-S-TMSI mod 1024  (see TS 38.304 section 7.1)
   asn1_paging->ue_id_idx_value.set_idx_len10().from_number(five_g_s_tmsi % 1024);