sec: split security engine interface into Tx and Rx

Author: robertfalkenberg

include/srsran/security/security_engine.h

@@ -25,13 +25,20 @@ struct security_result {
   uint32_t                              count;
 };
 
-class security_engine
+class security_engine_tx
 {
 public:
-  virtual ~security_engine() = default;
+  virtual ~security_engine_tx() = default;
 
   virtual security_result encrypt_and_protect_integrity(byte_buffer buf, size_t offset, uint32_t count) = 0;
-  virtual security_result decrypt_and_verify_integrity(byte_buffer buf, size_t offset, uint32_t count)  = 0;
+};
+
+class security_engine_rx
+{
+public:
+  virtual ~security_engine_rx() = default;
+
+  virtual security_result decrypt_and_verify_integrity(byte_buffer buf, size_t offset, uint32_t count) = 0;
 };
 
 } // namespace security

lib/pdcp/pdcp_entity_tx.h

@@ -181,7 +181,7 @@ class pdcp_entity_tx final : public pdcp_entity_tx_rx_base,
 
   pdcp_tx_state st = {};
 
-  std::unique_ptr<security::security_engine> sec_engine;
+  std::unique_ptr<security::security_engine_tx> sec_engine;
 
   security::integrity_enabled integrity_enabled = security::integrity_enabled::off;
   security::ciphering_enabled ciphering_enabled = security::ciphering_enabled::off;

lib/security/security_engine_impl.h

@@ -20,7 +20,7 @@
 namespace srsran {
 namespace security {
 
-class security_engine_impl final : public security_engine
+class security_engine_impl final : public security_engine_tx, public security_engine_rx
 {
 public:
   security_engine_impl(sec_128_as_config  sec_cfg,