add light validation mode

This mode enables skipping of auth checks, transaction signature recovery and other tests that can be inferred as passed if the node implicitly trusts the active set of producers to maintain correctness

libraries/chain/controller.cpp

@@ -1652,15 +1652,34 @@ optional<producer_schedule_type> controller::proposed_producers()const {
 }
 
 bool controller::skip_auth_check() const {
-   return my->replaying && !my->conf.force_all_checks && !my->in_trx_requiring_checks;
+   // replaying
+   bool consider_skipping = my->replaying;
+
+   // OR in light validation mode
+   consider_skipping = consider_skipping || my->conf.validation_mode == validation_mode::LIGHT;
+
+   return consider_skipping
+      && !my->conf.force_all_checks
+      && !my->in_trx_requiring_checks;
 }
 
 bool controller::skip_db_sessions() const {
-   return !my->conf.disable_replay_opts && my->pending && !my->in_trx_requiring_checks && my->pending->_block_status == block_status::irreversible;
+   bool consider_skipping = my->pending && my->pending->_block_status == block_status::irreversible;
+   return consider_skipping
+      && !my->conf.disable_replay_opts
+      && !my->in_trx_requiring_checks;
 }
 
 bool controller::skip_trx_checks() const {
-   return !my->conf.disable_replay_opts && my->pending && !my->in_trx_requiring_checks && (my->pending->_block_status == block_status::irreversible || my->pending->_block_status == block_status::validated);
+   // in a pending irreversible or previously validated block
+   bool consider_skipping = my->pending && ( my->pending->_block_status == block_status::irreversible || my->pending->_block_status == block_status::validated );
+
+   // OR in light validation mode
+   consider_skipping = consider_skipping || my->conf.validation_mode == validation_mode::LIGHT;
+
+   return consider_skipping
+      && !my->conf.disable_replay_opts
+      && !my->in_trx_requiring_checks;
 }
 
 bool controller::contracts_console()const {
@@ -1675,6 +1694,10 @@ db_read_mode controller::get_read_mode()const {
    return my->read_mode;
 }
 
+validation_mode controller::get_validation_mode()const {
+   return my->conf.validation_mode;
+}
+
 const apply_handler* controller::find_apply_handler( account_name receiver, account_name scope, action_name act ) const
 {
    auto native_handler_scope = my->apply_handlers.find( receiver );

libraries/chain/include/eosio/chain/controller.hpp

@@ -39,6 +39,11 @@ namespace eosio { namespace chain {
       IRREVERSIBLE
    };
 
+   enum class validation_mode {
+      FULL,
+      LIGHT
+   };
+
    class controller {
       public:
 
@@ -63,7 +68,8 @@ namespace eosio { namespace chain {
             genesis_state            genesis;
             wasm_interface::vm_type  wasm_runtime = chain::config::default_wasm_runtime;
 
-            db_read_mode             read_mode    = db_read_mode::SPECULATIVE;
+            db_read_mode             read_mode              = db_read_mode::SPECULATIVE;
+            validation_mode          validation_mode        = validation_mode::FULL;
 
             flat_set<account_name>   resource_greylist;
          };
@@ -221,6 +227,7 @@ namespace eosio { namespace chain {
          chain_id_type get_chain_id()const;
 
          db_read_mode get_read_mode()const;
+         validation_mode get_validation_mode()const;
 
          void set_subjective_cpu_leeway(fc::microseconds leeway);
 

plugins/chain_plugin/chain_plugin.cpp

@@ -72,6 +72,39 @@ void validate(boost::any& v,
   }
 }
 
+std::ostream& operator<<(std::ostream& osm, eosio::chain::validation_mode m) {
+   if ( m == eosio::chain::validation_mode::FULL ) {
+      osm << "full";
+   } else if ( m == eosio::chain::validation_mode::LIGHT ) {
+      osm << "light";
+   }
+
+   return osm;
+}
+
+void validate(boost::any& v,
+              std::vector<std::string> const& values,
+              eosio::chain::validation_mode* /* target_type */,
+              int)
+{
+  using namespace boost::program_options;
+
+  // Make sure no previous assignment to 'v' was made.
+  validators::check_first_occurrence(v);
+
+  // Extract the first string from 'values'. If there is more than
+  // one string, it's an error, and exception will be thrown.
+  std::string const& s = validators::get_single_string(values);
+
+  if ( s == "full" ) {
+     v = boost::any(eosio::chain::validation_mode::FULL);
+  } else if ( s == "light" ) {
+     v = boost::any(eosio::chain::validation_mode::LIGHT);
+  } else {
+     throw validation_error(validation_error::invalid_option_value);
+  }
+}
+
 }
 
 using namespace eosio;
@@ -202,6 +235,10 @@ void chain_plugin::set_program_options(options_description& cli, options_descrip
           "In \"speculative\" mode database contains changes done up to the head block plus changes made by transactions not yet included to the blockchain.\n"
           "In \"head\" mode database contains changes done up to the current head block.\n")
           //"In \"irreversible\" mode database contains changes done up the current irreversible block.\n")
+         ("validation-mode", boost::program_options::value<eosio::chain::validation_mode>()->default_value(eosio::chain::validation_mode::FULL),
+          "Chain validation mode (\"full\" or \"light\").\n"
+          "In \"full\" mode all incoming blocks will be fully validated.\n"
+          "In \"light\" mode all incoming blocks headers will be fully validated; transactions in those validated blocks will be trusted \n")
          ;
 
 // TODO: rate limiting
@@ -516,6 +553,10 @@ void chain_plugin::plugin_initialize(const variables_map& options) {
          EOS_ASSERT( my->chain_config->read_mode != db_read_mode::IRREVERSIBLE, plugin_config_exception, "irreversible mode not currently supported." );
       }
 
+      if ( options.count("validation-mode") ) {
+         my->chain_config->validation_mode = options.at("validation-mode").as<validation_mode>();
+      }
+
       my->chain.emplace( *my->chain_config );
       my->chain_id.emplace( my->chain->get_chain_id());
 

plugins/producer_plugin/producer_plugin.cpp

@@ -650,6 +650,10 @@ void producer_plugin::plugin_startup()
    EOS_ASSERT( my->_producers.empty() || chain.get_read_mode() == chain::db_read_mode::SPECULATIVE, plugin_config_exception,
               "node cannot have any producer-name configured because block production is impossible when read_mode is not \"speculative\"" );
 
+   EOS_ASSERT( my->_producers.empty() || chain.get_validation_mode() == chain::validation_mode::FULL, plugin_config_exception,
+              "node cannot have any producer-name configured because block production is not safe when validation_mode is not \"full\"" );
+
+
    my->_accepted_block_connection.emplace(chain.accepted_block.connect( [this]( const auto& bsp ){ my->on_block( bsp ); } ));
    my->_irreversible_block_connection.emplace(chain.irreversible_block.connect( [this]( const auto& bsp ){ my->on_irreversible_block( bsp->block ); } ));