rcpp_framework/core/net/tcp_connection.h

// This file is originally from Trantor - TcpConnection.h

// Copyright (c) 2016-2021, Tao An.  All rights reserved.

// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
//
//   * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//   * Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
//   * Neither the name of Tao An nor the names of other contributors
// may be used to endorse or promote products derived from this software
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//
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#pragma once

#include "core/containers/msg_buffer.h"
#include "core/loops/callbacks.h"
#include "core/loops/event_loop.h"
#include "core/net/inet_address.h"
#include <functional>
#include <memory>
#include <string>

class SSLContext;
std::shared_ptr<SSLContext> newSSLServerContext(
		const std::string &certPath,
		const std::string &keyPath,
		bool useOldTLS = false,
		const std::vector<std::pair<std::string, std::string> > &sslConfCmds = {});
/**
 * @brief This class represents a TCP connection.
 *
 */
class TcpConnection {
public:
	TcpConnection() = default;
	virtual ~TcpConnection(){};

	/**
	 * @brief Send some data to the peer.
	 *
	 * @param msg
	 * @param len
	 */
	virtual void send(const char *msg, size_t len) = 0;
	virtual void send(const void *msg, size_t len) = 0;
	virtual void send(const std::string &msg) = 0;
	virtual void send(std::string &&msg) = 0;
	virtual void send(const MsgBuffer &buffer) = 0;
	virtual void send(MsgBuffer &&buffer) = 0;
	virtual void send(const std::shared_ptr<std::string> &msgPtr) = 0;
	virtual void send(const std::shared_ptr<MsgBuffer> &msgPtr) = 0;

	/**
	 * @brief Send a file to the peer.
	 *
	 * @param fileName
	 * @param offset
	 * @param length
	 */
	virtual void sendFile(const char *fileName,
			size_t offset = 0,
			size_t length = 0) = 0;

	/**
	 * @brief Get the local address of the connection.
	 *
	 * @return const InetAddress&
	 */
	virtual const InetAddress &localAddr() const = 0;

	/**
	 * @brief Get the remote address of the connection.
	 *
	 * @return const InetAddress&
	 */
	virtual const InetAddress &peerAddr() const = 0;

	/**
	 * @brief Return true if the connection is established.
	 *
	 * @return true
	 * @return false
	 */
	virtual bool connected() const = 0;

	/**
	 * @brief Return false if the connection is established.
	 *
	 * @return true
	 * @return false
	 */
	virtual bool disconnected() const = 0;

	/**
	 * @brief Get the buffer in which the received data stored.
	 *
	 * @return MsgBuffer*
	 */
	virtual MsgBuffer *getRecvBuffer() = 0;

	/**
	 * @brief Set the high water mark callback
	 *
	 * @param cb The callback is called when the data in sending buffer is
	 * larger than the water mark.
	 * @param markLen The water mark in bytes.
	 */
	virtual void setHighWaterMarkCallback(const HighWaterMarkCallback &cb,
			size_t markLen) = 0;

	/**
	 * @brief Set the TCP_NODELAY option to the socket.
	 *
	 * @param on
	 */
	virtual void setTcpNoDelay(bool on) = 0;

	/**
	 * @brief Shutdown the connection.
	 * @note This method only closes the writing direction.
	 */
	virtual void shutdown() = 0;

	/**
	 * @brief Close the connection forcefully.
	 *
	 */
	virtual void forceClose() = 0;

	/**
	 * @brief Get the event loop in which the connection I/O is handled.
	 *
	 * @return EventLoop*
	 */
	virtual EventLoop *getLoop() = 0;

	/**
	 * @brief Set the custom data on the connection.
	 *
	 * @param context
	 */
	void setContext(const std::shared_ptr<void> &context) {
		contextPtr_ = context;
	}
	void setContext(std::shared_ptr<void> &&context) {
		contextPtr_ = std::move(context);
	}

	/**
	 * @brief Get the custom data from the connection.
	 *
	 * @tparam T
	 * @return std::shared_ptr<T>
	 */
	template <typename T>
	std::shared_ptr<T> getContext() const {
		return std::static_pointer_cast<T>(contextPtr_);
	}

	/**
	 * @brief Return true if the custom data is set by user.
	 *
	 * @return true
	 * @return false
	 */
	bool hasContext() const {
		return (bool)contextPtr_;
	}

	/**
	 * @brief Clear the custom data.
	 *
	 */
	void clearContext() {
		contextPtr_.reset();
	}

	/**
	 * @brief Call this method to avoid being kicked off by TcpServer, refer to
	 * the kickoffIdleConnections method in the TcpServer class.
	 *
	 */
	virtual void keepAlive() = 0;

	/**
	 * @brief Return true if the keepAlive() method is called.
	 *
	 * @return true
	 * @return false
	 */
	virtual bool isKeepAlive() = 0;

	/**
	 * @brief Return the number of bytes sent
	 *
	 * @return size_t
	 */
	virtual size_t bytesSent() const = 0;

	/**
	 * @brief Return the number of bytes received.
	 *
	 * @return size_t
	 */
	virtual size_t bytesReceived() const = 0;

	/**
	 * @brief Check whether the connection is SSL encrypted.
	 *
	 * @return true
	 * @return false
	 */
	virtual bool isSSLConnection() const = 0;

	/**
	 * @brief Start the SSL encryption on the connection (as a client).
	 *
	 * @param callback The callback is called when the SSL connection is
	 * established.
	 * @param hostname The server hostname for SNI. If it is empty, the SNI is
	 * not used.
	 * @param sslConfCmds The commands used to call the SSL_CONF_cmd function in
	 * OpenSSL.
	 */
	virtual void startClientEncryption(
			std::function<void()> callback,
			bool useOldTLS = false,
			bool validateCert = true,
			std::string hostname = "",
			const std::vector<std::pair<std::string, std::string> > &sslConfCmds = {}) = 0;

	/**
	 * @brief Start the SSL encryption on the connection (as a server).
	 *
	 * @param ctx The SSL context.
	 * @param callback The callback is called when the SSL connection is
	 * established.
	 */
	virtual void startServerEncryption(const std::shared_ptr<SSLContext> &ctx,
			std::function<void()> callback) = 0;

protected:
	bool validateCert_ = false;

private:
	std::shared_ptr<void> contextPtr_;
};