From f5c945dc2fe093c5c6529c550cd5fbade9d084c1 Mon Sep 17 00:00:00 2001
From: Andre Puschmann <andre@softwareradiosystems.com>
Date: Mon, 1 Feb 2021 21:32:00 +0100
Subject: [PATCH] mac_nr: add interface to set C-RNTI and contention ID from
 RRC

used during contention-based/free RA
---
 .../srslte/interfaces/ue_nr_interfaces.h      |  6 +++++
 srsue/hdr/stack/mac_nr/mac_nr.h               |  8 +++++--
 srsue/src/stack/mac_nr/mac_nr.cc              | 23 +++++++++++++++++++
 3 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/lib/include/srslte/interfaces/ue_nr_interfaces.h b/lib/include/srslte/interfaces/ue_nr_interfaces.h
index 1d9009b54..0468a606d 100644
--- a/lib/include/srslte/interfaces/ue_nr_interfaces.h
+++ b/lib/include/srslte/interfaces/ue_nr_interfaces.h
@@ -60,6 +60,12 @@ public:
   virtual void setup_lcid(const srslte::logical_channel_config_t& config) = 0;
   virtual void set_config(const srslte::bsr_cfg_t& bsr_cfg)               = 0;
   virtual void set_config(const srslte::sr_cfg_t& sr_cfg)                 = 0;
+
+  // RRC informs MAC about the (randomly) selected ID used for contention-based RA
+  virtual void set_contention_id(const uint64_t ue_identity) = 0;
+
+  // RRC informs MAC about new UE identity for contention-free RA
+  virtual bool set_crnti(const uint16_t crnti) = 0;
 };
 
 class phy_interface_mac_nr
diff --git a/srsue/hdr/stack/mac_nr/mac_nr.h b/srsue/hdr/stack/mac_nr/mac_nr.h
index a4c7ec031..875d63710 100644
--- a/srsue/hdr/stack/mac_nr/mac_nr.h
+++ b/srsue/hdr/stack/mac_nr/mac_nr.h
@@ -58,10 +58,12 @@ public:
 
   void get_metrics(mac_metrics_t* metrics);
 
-  /******** Interface for RRC (RRC -> MAC) ****************/
+  /// Interface for RRC (RRC -> MAC)
   void setup_lcid(const srslte::logical_channel_config_t& config);
   void set_config(const srslte::bsr_cfg_t& bsr_cfg);
   void set_config(const srslte::sr_cfg_t& sr_cfg);
+  void set_contention_id(const uint64_t ue_identity);
+  bool set_crnti(const uint16_t crnti);
 
   /// stack interface
   void process_pdus();
@@ -76,6 +78,7 @@ private:
 
   bool     has_crnti();
   uint16_t get_crnti();
+  bool     is_valid_crnti(const uint16_t crnti);
 
   /// Interaction with rest of the stack
   phy_interface_mac_nr*         phy = nullptr;
@@ -89,7 +92,8 @@ private:
 
   bool started = false;
 
-  uint16_t crnti = 0xdead;
+  uint16_t crnti         = 0xdead;
+  uint64_t contention_id = 0;
 
   static constexpr uint32_t MIN_RLC_PDU_LEN =
       5; ///< minimum bytes that need to be available in a MAC PDU for attempting to add another RLC SDU
diff --git a/srsue/src/stack/mac_nr/mac_nr.cc b/srsue/src/stack/mac_nr/mac_nr.cc
index 61b48d164..596c8289e 100644
--- a/srsue/src/stack/mac_nr/mac_nr.cc
+++ b/srsue/src/stack/mac_nr/mac_nr.cc
@@ -258,6 +258,29 @@ void mac_nr::set_config(const srslte::sr_cfg_t& sr_cfg)
   logger.warning("Not Scheduling Request Config yet");
 }
 
+void mac_nr::set_contention_id(uint64_t ue_identity)
+{
+  contention_id = ue_identity;
+}
+
+bool mac_nr::set_crnti(const uint16_t crnti_)
+{
+  if (is_valid_crnti(crnti_)) {
+    logger.info("Setting C-RNTI to 0x%X", crnti_);
+    crnti = crnti_;
+    return true;
+  } else {
+    logger.warning("Failed to set C-RNTI, 0x%X is not valid.", crnti_);
+    return false;
+  }
+}
+
+bool mac_nr::is_valid_crnti(const uint16_t crnti)
+{
+  // TS 38.321 15.3.0 Table 7.1-1
+  return (crnti >= 0x0001 && crnti <= 0xFFEF);
+}
+
 void mac_nr::get_metrics(mac_metrics_t m[SRSLTE_MAX_CARRIERS]) {}
 
 /**