mysql_routing.h

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/*
  Copyright (c) 2015, 2026, Oracle and/or its affiliates.
 
  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License, version 2.0,
  as published by the Free Software Foundation.
 
  This program is designed to work with certain software (including
  but not limited to OpenSSL) that is licensed under separate terms,
  as designated in a particular file or component or in included license
  documentation.  The authors of MySQL hereby grant you an additional
  permission to link the program and your derivative works with the
  separately licensed software that they have either included with
  the program or referenced in the documentation.
 
  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.
 
  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/
 
#ifndef ROUTING_MYSQLROUTING_INCLUDED
#define ROUTING_MYSQLROUTING_INCLUDED
 
#include "mysqlrouter/datatypes.h"
#include "mysqlrouter/routing_export.h"
#include "mysqlrouter/routing_plugin_export.h"
 
/** @file
 * @brief Defining the class MySQLRouting
 *
 * This file defines the main class `MySQLRouting` which is used to configure,
 * start and manage a connection routing from clients and MySQL servers.
 *
 */
 
#include <array>
#include <atomic>
#include <chrono>
#include <map>
#include <memory>
#include <mutex>
#include <stdexcept>
 
#ifndef _WIN32
#include <arpa/inet.h>
#include <netdb.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <sys/socket.h>
#include <unistd.h>
#else
#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#endif
 
#include "connection.h"
#include "connection_container.h"
#include "context.h"
#include "destination.h"
#include "destination_ssl_context.h"
#include "mysql/harness/filesystem.h"
#include "mysql/harness/net_ts/internet.h"
#include "mysql/harness/net_ts/io_context.h"
#include "mysql/harness/net_ts/local.h"
#include "mysql/harness/plugin.h"
#include "mysql/harness/stdx/monitor.h"
#include "mysql_router_thread.h"
#include "mysql_routing_base.h"
#include "mysqlrouter/base_protocol.h"
#include "mysqlrouter/io_thread.h"
#include "mysqlrouter/routing.h"
#include "mysqlrouter/routing_component.h"
#include "mysqlrouter/uri.h"
#include "plugin_config.h"
#include "socket_container.h"
#include "tcp_address.h"
 
namespace mysql_harness {
class PluginFuncEnv;
}  // namespace mysql_harness
 
class MySQLRouting;
 
class ROUTING_EXPORT AcceptingEndpoint {
 public:
  AcceptingEndpoint(net::io_context &io_ctx,
                    const std::string &parent_routing_name)
      : io_ctx_(io_ctx), parent_routing_name_(parent_routing_name) {}
 
  AcceptingEndpoint(const AcceptingEndpoint &) = delete;
 
  virtual stdx::expected<void, std::error_code> setup() = 0;
  virtual stdx::expected<void, std::error_code> cancel() = 0;
  virtual bool is_open() const = 0;
 
  virtual void start(MySQLRouting *r, std::list<IoThread> &,
                     WaitableMonitor<bool> &waitable) = 0;
 
  virtual std::string name() = 0;
 
  virtual ~AcceptingEndpoint() {}
 
 protected:
  net::io_context &io_ctx_;
  // used when the acceptor logs
  std::string parent_routing_name_;
};
 
class ROUTING_EXPORT AcceptingEndpointTcpSocket : public AcceptingEndpoint {
 public:
  AcceptingEndpointTcpSocket(net::io_context &io_ctx,
                             const std::string &parent_routing_name,
                             const std::string &address, uint16_t port);
 
  stdx::expected<void, std::error_code> setup() override;
  stdx::expected<void, std::error_code> cancel() override;
  bool is_open() const override;
 
  void start(MySQLRouting *r, std::list<IoThread> &,
             WaitableMonitor<bool> &waitable) override;
 
  std::string name() override;
 
 private:
  net::ip::tcp::acceptor service_;
  net::ip::tcp::endpoint service_endpoint_;
 
  std::string address_;
  uint16_t port_;
};
 
#ifndef _WIN32
class ROUTING_EXPORT AcceptingEndpointUnixSocket : public AcceptingEndpoint {
 public:
  AcceptingEndpointUnixSocket(net::io_context &io_ctx,
                              const std::string &parent_routing_name,
                              const std::string &socket_name);
 
  stdx::expected<void, std::error_code> setup() override;
  stdx::expected<void, std::error_code> cancel() override;
  bool is_open() const override;
 
  void start(MySQLRouting *r, std::list<IoThread> &,
             WaitableMonitor<bool> &waitable) override;
 
  std::string name() override;
 
 private:
  local::stream_protocol::acceptor service_;
  local::stream_protocol::endpoint service_endpoint_;
 
  std::string socket_name_;
};
#endif
 
/** @class MySQLRouting
 *  @brief Manage Connections from clients to MySQL servers
 *
 *  The class MySQLRouter is used to start a service listening on a particular
 *  TCP port for incoming MySQL Client connection and route these to a MySQL
 *  Server.
 */
class ROUTING_EXPORT MySQLRouting : public MySQLRoutingBase {
 public:
  /** @brief Default constructor
   *
   * @param routing_config routing configuration
   * @param io_ctx IO context for routing connections
   * @param acceptor_io_ctx IO context for accepting client connections
   * @param route_name Name of connection routing (can be empty string)
   * @param client_ssl_ctx SSL context of the client side
   * @param dest_ssl_ctx SSL contexts of the destinations
   */
  MySQLRouting(const RoutingConfig &routing_config, net::io_context &io_ctx,
               net::io_context &acceptor_io_ctx,
               const std::string &route_name = {},
               TlsServerContext *client_ssl_ctx = nullptr,
               DestinationTlsContext *dest_ssl_ctx = nullptr);
 
  MySQLRouting(const RoutingConfig &routing_config, net::io_context &io_ctx,
               const std::string &route_name = {},
               TlsServerContext *client_ssl_ctx = nullptr,
               DestinationTlsContext *dest_ssl_ctx = nullptr);
 
  /** @brief Runs the service and accept incoming connections
   *
   * Runs the connection routing service and starts accepting incoming
   * MySQL client connections.
   *
   * @throw std::runtime_error on errors.
   *
   */
  void run(mysql_harness::PluginFuncEnv *env);
 
  /** @brief Sets the destinations from URI
   *
   * Sets destinations using the given string. The string should be a comma
   * separated list of MySQL servers.
   *
   * Example of destinations:
   *   "10.0.10.5,10.0.11.6:3307"
   *
   * @param csv destinations as comma-separated-values
   */
  void set_destinations_from_csv(const std::string &csv);
 
  void set_destinations_from_uri(const mysqlrouter::URI &uri);
 
  /** @brief Returns timeout when connecting to destination
   *
   * @return Timeout in seconds as int
   */
  std::chrono::milliseconds get_destination_connect_timeout() const noexcept {
    return context_.get_destination_connect_timeout();
  }
 
  /** @brief Sets timeout when connecting to destination
   *
   * Checks timeout connecting with destination servers.
   *
   * @throw std::invalid_argument when an invalid value was provided.
   *
   * @param timeout Timeout
   */
  void validate_destination_connect_timeout(std::chrono::milliseconds timeout);
 
  /** @brief Sets maximum active connections
   *
   * Sets maximum of active connections. Maximum must be between 1 and
   * 65535.
   *
   * @throw std::invalid_argument when an invalid value was provided.
   *
   * @param maximum Max number of connections allowed
   * @return New value as int
   */
  int set_max_connections(int maximum);
 
  /** @brief Returns maximum active connections
   *
   * @return Maximum as int
   */
  int get_max_connections() const noexcept override { return max_connections_; }
 
  /**
   * create new connection to MySQL Server than can handle client's
   * traffic and adds it to connection container.
   *
   * @param client_socket socket used to transfer data to/from client
   * @param client_endpoint endpoint of client
   */
  template <class ClientProtocol>
  void create_connection(
      typename ClientProtocol::socket client_socket,
      const typename ClientProtocol::endpoint &client_endpoint);
 
  routing::RoutingStrategy get_routing_strategy() const override;
 
  std::vector<mysql_harness::TCPAddress> get_destinations() const override;
 
  std::vector<MySQLRoutingAPI::ConnData> get_connections() override;
 
  MySQLRoutingConnectionBase *get_connection(const std::string &) override;
 
  RouteDestination *destinations() { return destination_.get(); }
 
  void disconnect_all();
 
  /**
   * Stop accepting new connections on a listening socket.
   */
  void stop_socket_acceptors() override;
 
  /**
   * Check if we are accepting connections on a routing socket.
   *
   * @retval true if we are accepting connections, false otherwise
   */
  bool is_accepting_connections() const override;
 
  /**
   * Refresh routing socket acceptor state based on currently usable
   * destinations.
   *
   * @returns std::string on errors.
   */
  stdx::expected<void, std::string> refresh_socket_acceptor_state() override;
 
 private:
  /** @brief Sets unix socket permissions so that the socket is accessible
   *         to all users (no-op on Windows)
   * @param socket_file path to socket file
   *
   * @throw std::runtime_error if chmod() inside fails
   */
  static void set_unix_socket_permissions(const char *socket_file);
 
  stdx::expected<void, std::string> run_acceptor(
      mysql_harness::PluginFuncEnv *env);
 
  stdx::expected<void, std::string> start_accepting_connections();
  stdx::expected<void, std::string> restart_accepting_connections();
 
  /** Stop socket acceptors while socket_acceptor_state_mtx_ is held. */
  void stop_socket_acceptors_unlocked();
 
 public:
  MySQLRoutingContext &get_context() override { return context_; }
 
  bool is_running() const override { return is_running_; }
 
  /**
   * get the purpose of connections to this route.
   *
   * - read-write : all statements are treated as "read-write".
   * - read-only  : all statements are treated as "read-only".
   * - unavailable: it is currently unknown where the statement should go to.
   *
   * "Unavailable" is used for read-write splitting where the purpose is
   * determined per statement, session, ...
   *
   * A statement over a read-only server connection may end up on a read-write
   * server in case all read-only servers aren't reachable. Even if the server
   * is read-write, the connections purpose is read-only and if the server
   * changes its role from PRIMARY to SECONDARY, these read-only connections
   * will not be abort as a SECONDARY is good enough to serve read-only
   * connections.
   */
  mysqlrouter::ServerMode purpose() const override;
 
 private:
  /** Monitor for controlling and notifying socket acceptors. */
  WaitableMonitor<bool> acceptor_waitable_{false};
 
  /** @brief wrapper for data used by all connections */
  MySQLRoutingContext context_;
 
  net::io_context &io_ctx_;
  net::io_context &acceptor_io_ctx_;
 
  /** @brief Destination object to use when getting next connection */
  std::unique_ptr<RouteDestination> destination_;
 
  bool is_destination_standalone_{false};
 
  /** @brief Routing strategy to use when getting next destination */
  routing::RoutingStrategy routing_strategy_;
 
  /** @brief access_mode of the servers in the routing */
  routing::AccessMode access_mode_;
 
  /** @brief Maximum active connections
   *
   * Maximum number of incoming connections that will be accepted
   * by this MySQLRouter instances. There is no maximum for outgoing
   * connections since it is one-to-one with incoming.
   */
  int max_connections_;
 
  /** @brief used to unregister from subscription on allowed nodes changes */
  AllowedNodesChangeCallbacksListIterator allowed_nodes_list_iterator_;
 
  /** @brief container for connections */
  ConnectionContainer connection_container_;
 
  /** Information if the routing plugin is still running. */
  std::atomic<bool> is_running_{true};
 
  /** Serializes socket acceptor state transitions. */
  std::mutex socket_acceptor_state_mtx_;
 
  /** Used when the accepting port is been reopened and it failed, to schedule
   * another retry for standalone-destination(s) route. */
  net::steady_timer accept_port_reopen_retry_timer_{io_ctx_};
 
#ifdef FRIEND_TEST
  FRIEND_TEST(RoutingTests, bug_24841281);
  FRIEND_TEST(RoutingTests, get_routing_thread_name);
  FRIEND_TEST(RoutingTests, NoAcceptorRestartRetryAfterRoutingStops);
  FRIEND_TEST(ClassicProtocolRoutingTest, NoValidDestinations);
  FRIEND_TEST(TestSetupTcpService, single_addr_ok);
  FRIEND_TEST(TestSetupTcpService, getaddrinfo_fails);
  FRIEND_TEST(TestSetupTcpService, socket_fails_for_all_addr);
  FRIEND_TEST(TestSetupTcpService, socket_fails);
  FRIEND_TEST(TestSetupTcpService, bind_fails);
  FRIEND_TEST(TestSetupTcpService, listen_fails);
#ifndef _WIN32
  FRIEND_TEST(TestSetupTcpService, setsockopt_fails);
  FRIEND_TEST(TestSetupNamedSocketService, unix_socket_permissions_failure);
#endif
#endif
 
  std::vector<std::unique_ptr<AcceptingEndpoint>> accepting_endpoints_;
};
 
extern "C" {
extern mysql_harness::Plugin ROUTING_PLUGIN_EXPORT harness_plugin_routing;
}
 
#endif  // ROUTING_MYSQLROUTING_INCLUDED