nr,gnb,rrc: implement basic NR RRC bearer addition and reconf message sending

lib/include/srsran/asn1/rrc_nr_utils.h

@@ -60,6 +60,9 @@ struct pdcch_cfg_common_s;
 struct pdcch_cfg_s;
 struct mib_s;
 
+struct srb_to_add_mod_s;
+struct drb_to_add_mod_s;
+
 } // namespace rrc_nr
 } // namespace asn1
 
@@ -144,4 +147,16 @@ pdcp_config_t make_drb_pdcp_config_t(const uint8_t bearer_id, bool is_ue, const
 
 } // namespace srsran
 
+/************************
+ * ASN1 RRC extensions
+ ***********************/
+namespace asn1 {
+
+namespace rrc_nr {
+bool operator==(const srb_to_add_mod_s& lhs, const srb_to_add_mod_s& rhs);
+bool operator==(const drb_to_add_mod_s& lhs, const drb_to_add_mod_s& rhs);
+} // namespace rrc_nr
+
+} // namespace asn1
+
 #endif // SRSRAN_RRC_NR_UTILS_H

lib/src/asn1/rrc_nr_utils.cc

@@ -1624,3 +1624,29 @@ ASN1_OBJ_ID_DEFINE(asn1::rrc_nr::report_cfg_to_add_mod_s, report_cfg_id);
 ASN1_OBJ_ID_DEFINE(asn1::rrc_nr::meas_id_to_add_mod_s, meas_id);
 
 } // namespace srsran
+
+namespace asn1 {
+
+namespace rrc_nr {
+
+bool operator==(const srb_to_add_mod_s& lhs, const srb_to_add_mod_s& rhs)
+{
+  if (lhs.srb_id != rhs.srb_id or lhs.pdcp_cfg_present != rhs.pdcp_cfg_present) {
+    return false;
+  }
+  // TODO: check remaining fields
+  return true;
+}
+bool operator==(const drb_to_add_mod_s& lhs, const drb_to_add_mod_s& rhs)
+{
+  if (lhs.drb_id != rhs.drb_id or lhs.pdcp_cfg_present != rhs.pdcp_cfg_present or
+      lhs.cn_assoc_present != rhs.cn_assoc_present) {
+    return false;
+  }
+  // TODO: check remaining fields
+  return true;
+}
+
+} // namespace rrc_nr
+
+} // namespace asn1

srsgnb/hdr/stack/rrc/cell_asn1_config.h

@@ -30,6 +30,15 @@ int fill_master_cell_cfg_from_enb_cfg(const rrc_nr_cfg_t& cfg, uint32_t cc, asn1
 int fill_mib_from_enb_cfg(const rrc_cell_cfg_nr_t& cell_cfg, asn1::rrc_nr::mib_s& mib);
 int fill_sib1_from_enb_cfg(const rrc_nr_cfg_t& cfg, uint32_t cc, asn1::rrc_nr::sib1_s& sib1);
 
+/**
+ * Based on the previous and new radio bearer config, generate ASN1 diff
+ * @return if a change was detected
+ */
+bool compute_diff_radio_bearer_cfg(const rrc_nr_cfg_t&                     cfg,
+                                   const asn1::rrc_nr::radio_bearer_cfg_s& prev_bearers,
+                                   const asn1::rrc_nr::radio_bearer_cfg_s& next_bearers,
+                                   asn1::rrc_nr::radio_bearer_cfg_s&       diff);
+
 /// Apply radioBearerConfig updates to CellGroupConfig
 void fill_cellgroup_with_radio_bearer_cfg(const rrc_nr_cfg_t&                     cfg,
                                           const asn1::rrc_nr::radio_bearer_cfg_s& bearers,

srsgnb/hdr/stack/rrc/rrc_nr_ue.h

@@ -149,7 +149,7 @@ private:
 
   // RRC configs for UEs
   asn1::rrc_nr::cell_group_cfg_s   cell_group_cfg;
-  asn1::rrc_nr::radio_bearer_cfg_s radio_bearer_cfg;
+  asn1::rrc_nr::radio_bearer_cfg_s radio_bearer_cfg, next_radio_bearer_cfg;
 
   // MAC controller
   sched_nr_interface::ue_cfg_t uecfg{};

srsgnb/src/stack/rrc/cell_asn1_config.cc

@@ -11,6 +11,7 @@
  */
 
 #include "srsgnb/hdr/stack/rrc/cell_asn1_config.h"
+#include "srsran/asn1/obj_id_cmp_utils.h"
 #include "srsran/asn1/rrc_nr_utils.h"
 #include "srsran/common/band_helper.h"
 #include <bitset>
@@ -1169,6 +1170,28 @@ int fill_sib1_from_enb_cfg(const rrc_nr_cfg_t& cfg, uint32_t cc, asn1::rrc_nr::s
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 
+bool compute_diff_radio_bearer_cfg(const rrc_nr_cfg_t&       cfg,
+                                   const radio_bearer_cfg_s& prev_bearers,
+                                   const radio_bearer_cfg_s& next_bearers,
+                                   radio_bearer_cfg_s&       diff)
+{
+  // Compute SRB differences
+  std::vector<uint8_t> srbs_to_rem;
+  srsran::compute_cfg_diff(
+      prev_bearers.srb_to_add_mod_list, next_bearers.srb_to_add_mod_list, diff.srb_to_add_mod_list, srbs_to_rem);
+  diff.srb_to_add_mod_list_present = diff.srb_to_add_mod_list.size() > 0;
+
+  // Compute DRB differences
+  srsran::compute_cfg_diff(prev_bearers.drb_to_add_mod_list,
+                           next_bearers.drb_to_add_mod_list,
+                           diff.drb_to_add_mod_list,
+                           diff.drb_to_release_list);
+  diff.drb_to_add_mod_list_present = diff.drb_to_add_mod_list.size() > 0;
+  diff.drb_to_release_list_present = diff.drb_to_release_list.size() > 0;
+
+  return diff.srb_to_add_mod_list_present or diff.drb_to_release_list_present or diff.drb_to_add_mod_list_present;
+}
+
 void fill_cellgroup_with_radio_bearer_cfg(const rrc_nr_cfg_t&                     cfg,
                                           const asn1::rrc_nr::radio_bearer_cfg_s& bearers,
                                           asn1::rrc_nr::cell_group_cfg_s&         out)

srsgnb/src/stack/rrc/rrc_nr_ue.cc

@@ -879,23 +879,28 @@ void rrc_nr::ue::send_rrc_setup()
 {
   const uint8_t max_wait_time_secs = 16;
 
+  // Add SRB1 to UE context
+  // Note: See 5.3.5.6.3 - SRB addition/modification
+  next_radio_bearer_cfg.srb_to_add_mod_list_present = true;
+  next_radio_bearer_cfg.srb_to_add_mod_list.resize(1);
+  srb_to_add_mod_s& srb1 = next_radio_bearer_cfg.srb_to_add_mod_list[0];
+  srb1.srb_id            = 1;
+
+  // Generate RRC setup message
+
   dl_ccch_msg_s msg;
   rrc_setup_s&  setup        = msg.msg.set_c1().set_rrc_setup();
   setup.rrc_transaction_id   = (uint8_t)((transaction_id++) % 4);
   rrc_setup_ies_s& setup_ies = setup.crit_exts.set_rrc_setup();
 
   // Fill RRC Setup
-  // Note: See 5.3.5.6.3 - SRB addition/modification
+  // - Setup SRB1
-  setup_ies.radio_bearer_cfg.srb_to_add_mod_list_present = true;
+  compute_diff_radio_bearer_cfg(parent->cfg, radio_bearer_cfg, next_radio_bearer_cfg, setup_ies.radio_bearer_cfg);
-  setup_ies.radio_bearer_cfg.srb_to_add_mod_list.resize(1);
-  srb_to_add_mod_s& srb1 = setup_ies.radio_bearer_cfg.srb_to_add_mod_list[0];
-  srb1.srb_id            = 1;
 
+  // - Setup masterCellGroup
   asn1::rrc_nr::cell_group_cfg_s master_cell_group = *parent->cell_ctxt->master_cell_group;
-
+  // - Derive master cell group config bearers
-  // Derive master cell group config bearers
   fill_cellgroup_with_radio_bearer_cfg(parent->cfg, setup_ies.radio_bearer_cfg, master_cell_group);
-
   {
     srsran::unique_byte_buffer_t pdu = srsran::make_byte_buffer();
     asn1::bit_ref                bref{pdu->data(), pdu->get_tailroom()};
@@ -921,7 +926,8 @@ void rrc_nr::ue::send_rrc_setup()
 /// TS 38.331, RRCSetupComplete
 void rrc_nr::ue::handle_rrc_setup_complete(const asn1::rrc_nr::rrc_setup_complete_s& msg)
 {
-  // TODO: handle RRCSetupComplete
+  // Update current radio bearer cfg
+  radio_bearer_cfg = next_radio_bearer_cfg;
 
   // Create UE context in NGAP
   using ngap_cause_t = asn1::ngap_nr::rrcestablishment_cause_opts::options;
@@ -959,6 +965,10 @@ void rrc_nr::ue::send_rrc_reconfiguration()
   dl_dcch_msg.msg.set_c1().set_rrc_recfg().rrc_transaction_id = (uint8_t)((transaction_id++) % 4);
   rrc_recfg_ies_s& ies = dl_dcch_msg.msg.c1().rrc_recfg().crit_exts.set_rrc_recfg();
 
+  // Add new SRBs/DRBs
+  ies.radio_bearer_cfg_present =
+      compute_diff_radio_bearer_cfg(parent->cfg, radio_bearer_cfg, next_radio_bearer_cfg, ies.radio_bearer_cfg);
+
   ies.non_crit_ext_present                   = true;
   ies.non_crit_ext.master_cell_group_present = false; // TODO
 
@@ -969,7 +979,7 @@ void rrc_nr::ue::send_rrc_reconfiguration()
 
 void rrc_nr::ue::handle_rrc_reconfiguration_complete(const asn1::rrc_nr::rrc_recfg_complete_s& msg)
 {
-  // TODO: handle RRCReconfComplete
+  radio_bearer_cfg = next_radio_bearer_cfg;
 }
 
 void rrc_nr::ue::send_dl_information_transfer(srsran::unique_byte_buffer_t sdu)
@@ -991,7 +1001,40 @@ void rrc_nr::ue::handle_ul_information_transfer(const asn1::rrc_nr::ul_info_tran
   parent->ngap->write_pdu(rnti, msg.crit_exts.ul_info_transfer().ded_nas_msg);
 }
 
-void rrc_nr::ue::establish_eps_bearer(uint32_t pdu_session_id, srsran::const_byte_span nas_pdu, uint32_t lcid) {}
+void rrc_nr::ue::establish_eps_bearer(uint32_t pdu_session_id, srsran::const_byte_span nas_pdu, uint32_t lcid)
+{
+  // Add SRB2, if not yet added
+  if (radio_bearer_cfg.srb_to_add_mod_list.size() <= 1) {
+    next_radio_bearer_cfg.srb_to_add_mod_list_present = true;
+    next_radio_bearer_cfg.srb_to_add_mod_list.resize(1);
+    next_radio_bearer_cfg.srb_to_add_mod_list[0].srb_id = 2;
+  }
+
+  drb_to_add_mod_s drb;
+  drb.cn_assoc_present                                    = true;
+  drb.cn_assoc.set_sdap_cfg().pdu_session                 = 1;
+  drb.cn_assoc.sdap_cfg().sdap_hdr_dl.value               = asn1::rrc_nr::sdap_cfg_s::sdap_hdr_dl_opts::absent;
+  drb.cn_assoc.sdap_cfg().sdap_hdr_ul.value               = asn1::rrc_nr::sdap_cfg_s::sdap_hdr_ul_opts::absent;
+  drb.cn_assoc.sdap_cfg().default_drb                     = true;
+  drb.cn_assoc.sdap_cfg().mapped_qos_flows_to_add_present = true;
+  drb.cn_assoc.sdap_cfg().mapped_qos_flows_to_add.resize(1);
+  drb.cn_assoc.sdap_cfg().mapped_qos_flows_to_add[0] = 1;
+
+  drb.drb_id                               = 1;
+  drb.pdcp_cfg_present                     = true;
+  drb.pdcp_cfg.drb.discard_timer_present   = true;
+  drb.pdcp_cfg.drb.discard_timer.value     = pdcp_cfg_s::drb_s_::discard_timer_opts::ms100;
+  drb.pdcp_cfg.drb.pdcp_sn_size_ul_present = true;
+  drb.pdcp_cfg.drb.pdcp_sn_size_ul.value   = asn1::rrc_nr::pdcp_cfg_s::drb_s_::pdcp_sn_size_ul_opts::len18bits;
+  drb.pdcp_cfg.drb.pdcp_sn_size_dl_present = true;
+  drb.pdcp_cfg.drb.pdcp_sn_size_dl.value   = asn1::rrc_nr::pdcp_cfg_s::drb_s_::pdcp_sn_size_dl_opts::len18bits;
+  drb.pdcp_cfg.drb.hdr_compress.set_not_used();
+  drb.pdcp_cfg.t_reordering_present = true;
+  drb.pdcp_cfg.t_reordering.value   = asn1::rrc_nr::pdcp_cfg_s::t_reordering_opts::ms0;
+
+  next_radio_bearer_cfg.drb_to_add_mod_list_present = true;
+  next_radio_bearer_cfg.drb_to_add_mod_list.push_back(drb);
+}
 
 bool rrc_nr::ue::init_pucch()
 {