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/*
* Author: Sven Gothel <sgothel@jausoft.com>
* Copyright (c) 2020 Gothel Software e.K.
* Copyright (c) 2020 ZAFENA AB
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#ifndef L2CAP_COMM_HPP_
#define L2CAP_COMM_HPP_
#include <cstring>
#include <string>
#include <memory>
#include <cstdint>
#include <mutex>
#include <atomic>
#include <jau/environment.hpp>
#include "UUID.hpp"
#include "BTTypes0.hpp"
/**
* - - - - - - - - - - - - - - -
*
* Module L2CAPComm:
*
* - BT Core Spec v5.2: Vol 3, Part A: BT Logical Link Control and Adaption Protocol (L2CAP)
*/
namespace direct_bt {
class BTDevice; // forward
/**
* L2CAP Singleton runtime environment properties
* <p>
* Also see {@link DBTEnv::getExplodingProperties(const std::string & prefixDomain)}.
* </p>
*/
class L2CAPEnv : public jau::root_environment {
private:
L2CAPEnv() noexcept;
const bool exploding; // just to trigger exploding properties
public:
/**
* L2CAP poll timeout for reading, defaults to 10s.
* <p>
* Environment variable is 'direct_bt.l2cap.reader.timeout'.
* </p>
*/
const int32_t L2CAP_READER_POLL_TIMEOUT;
/**
* Debugging facility: L2CAP restart count on transmission errors, defaults to 5 attempts.
* <p>
* If negative, L2CAPComm will abort() the program.
* </p>
* <p>
* Environment variable is 'direct_bt.l2cap.restart.count'.
* </p>
*/
const int32_t L2CAP_RESTART_COUNT_ON_ERROR;
/**
* Debug all GATT Data communication
* <p>
* Environment variable is 'direct_bt.debug.l2cap.data'.
* </p>
*/
const bool DEBUG_DATA;
public:
static L2CAPEnv& get() noexcept {
/**
* Thread safe starting with C++11 6.7:
*
* If control enters the declaration concurrently while the variable is being initialized,
* the concurrent execution shall wait for completion of the initialization.
*
* (Magic Statics)
*
* Avoiding non-working double checked locking.
*/
static L2CAPEnv e;
return e;
}
};
/**
* Read/Write L2CAP communication channel.
*/
class L2CAPComm {
public:
enum class Defaults : int {
L2CAP_CONNECT_MAX_RETRY = 3
};
static constexpr int number(const Defaults d) { return static_cast<int>(d); }
static std::string getStateString(bool isConnected, bool hasIOError) {
return "State[open "+std::to_string(isConnected)+", ioError "+std::to_string(hasIOError)+"]";
}
private:
static int l2cap_open_dev(const BDAddressAndType & adapterAddressAndType, const L2CAP_PSM psm, const L2CAP_CID cid);
static int l2cap_close_dev(int dd);
const L2CAPEnv & env;
const BDAddressAndType adapterAddressAndType;
const L2CAP_PSM psm;
const L2CAP_CID cid;
std::recursive_mutex mtx_write;
BDAddressAndType deviceAddressAndType;
std::atomic<int> socket_descriptor; // the l2cap socket
std::atomic<bool> is_open; // reflects state
std::atomic<bool> has_ioerror; // reflects state
std::atomic<bool> interrupt_flag; // for forced disconnect
std::atomic<pthread_t> tid_connect;
std::atomic<pthread_t> tid_read;
bool setBTSecurityLevelImpl(const BTSecurityLevel sec_level);
BTSecurityLevel getBTSecurityLevelImpl();
public:
/**
* Constructing a non connected L2CAP channel instance for the pre-defined PSM and CID.
*/
L2CAPComm(const BDAddressAndType& adapterAddressAndType, const L2CAP_PSM psm, const L2CAP_CID cid);
L2CAPComm(const L2CAPComm&) = delete;
void operator=(const L2CAPComm&) = delete;
/** Destructor closing the L2CAP channel, see {@link #disconnect()}. */
~L2CAPComm() noexcept { close(); }
/**
* Opens and connects the L2CAP channel, locking {@link #mutex_write()}.
* <p>
* BT Core Spec v5.2: Vol 3, Part A: L2CAP_CONNECTION_REQ
* </p>
*
* @param device the remote device to establish this L2CAP connection
* @param sec_level sec_level < BTSecurityLevel::NONE will not set security level
* @return true if connection has been established, otherwise false
*/
bool open(const BTDevice& device, const BTSecurityLevel sec_level=BTSecurityLevel::NONE);
bool isOpen() const { return is_open; }
/** Closing the L2CAP channel, locking {@link #mutex_write()}. */
bool close() noexcept;
/** Return this L2CAP socket descriptor. */
inline int getSocketDescriptor() const noexcept { return socket_descriptor; }
bool hasIOError() const { return has_ioerror; }
std::string getStateString() const { return getStateString(is_open, has_ioerror); }
/** Return the recursive write mutex for multithreading access. */
std::recursive_mutex & mutex_write() { return mtx_write; }
/**
* If sec_level > ::BTSecurityLevel::UNSET, sets the BlueZ's L2CAP socket BT_SECURITY sec_level, determining the SMP security mode per connection.
* <p>
* To unset security, the L2CAP socket should be closed and opened again.
* </p>
*
* @param sec_level sec_level < ::BTSecurityLevel::NONE will not set security level and returns false.
* @return true if a security level > ::BTSecurityLevel::UNSET has been set successfully, false if no security level has been set or if it failed.
*/
bool setBTSecurityLevel(const BTSecurityLevel sec_level);
/**
* Fetches the current BlueZ's L2CAP socket BT_SECURITY sec_level.
*
* @return ::BTSecurityLevel sec_level value, ::BTSecurityLevel::UNSET if failure
*/
BTSecurityLevel getBTSecurityLevel();
/** Generic read, w/o locking suitable for a unique ringbuffer sink. Using L2CAPEnv::L2CAP_READER_POLL_TIMEOUT.*/
jau::snsize_t read(uint8_t* buffer, const jau::nsize_t capacity);
/** Generic write, locking {@link #mutex_write()}. */
jau::snsize_t write(const uint8_t *buffer, const jau::nsize_t length);
};
} // namespace direct_bt
#endif /* L2CAP_COMM_HPP_ */
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