Added encryption simulation in dbsim

Option --encryption=1 enables encryption simulation in dbsim. The
`do_crypt()` callback flips bits of input buffer and writes to output.

dbsim/db_params.cpp

@@ -69,6 +69,8 @@ db::params db::parse_args(int argc, char** argv)
          "number of rows per table")
         ("alg-freq", po::value<size_t>(&params.alg_freq),
          "ALG frequency")
+        ("encryption", po::value<bool>(&params.encryption),
+         "Enable encryption callback")
         ("debug-log-level", po::value<int>(&params.debug_log_level),
          "debug logging level: 0 - none, 1 - verbose")
         ("fast-exit", po::value<int>(&params.fast_exit),

dbsim/db_params.hpp

@@ -32,6 +32,7 @@ namespace db
         size_t n_transactions;
         size_t n_rows;
         size_t alg_freq;
+        bool encryption;
         std::string topology;
         std::string wsrep_provider;
         std::string wsrep_provider_options;
@@ -43,6 +44,7 @@ namespace db
             , n_transactions(0)
             , n_rows(1000)
             , alg_freq(0)
+            , encryption(false)
             , topology()
             , wsrep_provider()
             , wsrep_provider_options()

dbsim/db_server_service.cpp

@@ -165,10 +165,16 @@ void db::server_service::debug_sync(const char*)
 int db::server_service::do_crypt(void**                ctx         WSREP_UNUSED,
                                  wsrep::const_buffer&  key         WSREP_UNUSED,
                                  const char            (*iv)[32]   WSREP_UNUSED,
-                                 wsrep::const_buffer&  input       WSREP_UNUSED,
+                                 wsrep::const_buffer&  input,
-                                 void*                 output      WSREP_UNUSED,
+                                 void*                 output,
                                  bool                  encrypt     WSREP_UNUSED,
                                  bool                  last        WSREP_UNUSED)
 {
-    return -1;
+
+    for (size_t i(0); i < input.size(); ++i)
+    {
+        static_cast<unsigned char*>(output)[i] =
+            ~static_cast<const unsigned char*>(input.data())[i];
+    }
+    return input.size();
 }

dbsim/db_server_service.hpp

@@ -65,7 +65,6 @@ namespace db
                      void*                 output,
                      bool                  encrypt,
                      bool                  last) override;
-                     
     private:
         db::server& server_;
     };

dbsim/db_simulator.cpp

@@ -140,7 +140,7 @@ void db::simulator::start()
         std::string server_options(params_.wsrep_provider_options);
 
         if (server.server_state().load_provider(
-                params_.wsrep_provider, server_options, false))
+                params_.wsrep_provider, server_options, params_.encryption))
         {
             throw wsrep::runtime_error("Failed to load provider");
         }