Files
esp-nimble-cpp/src/NimBLEL2CAPChannel.h
2025-06-02 18:06:40 -06:00

127 lines
4.8 KiB
C++

//
// (C) Dr. Michael 'Mickey' Lauer <mickey@vanille-media.de>
//
#ifndef NIMBLE_CPP_L2CAPCHANNEL_H_
#define NIMBLE_CPP_L2CAPCHANNEL_H_
#include "nimconfig.h"
#if CONFIG_BT_ENABLED && CONFIG_BT_NIMBLE_L2CAP_COC_MAX_NUM
# include "inttypes.h"
# if defined(CONFIG_NIMBLE_CPP_IDF)
# include "host/ble_l2cap.h"
# include "os/os_mbuf.h"
# else
# include "nimble/nimble/host/include/host/ble_l2cap.h"
# include "nimble/porting/nimble/include/os/os_mbuf.h"
# endif
/**** FIX COMPILATION ****/
# undef min
# undef max
/**************************/
# include <vector>
# include <atomic>
class NimBLEClient;
class NimBLEL2CAPChannelCallbacks;
struct NimBLETaskData;
/**
* @brief Encapsulates a L2CAP channel.
*
* This class is used to encapsulate a L2CAP connection oriented channel, both
* from the "server" (which waits for the connection to be opened) and the "client"
* (which opens the connection) point of view.
*/
class NimBLEL2CAPChannel {
public:
/// @brief Open an L2CAP channel via the specified PSM and MTU.
/// @param[in] psm The PSM to use.
/// @param[in] mtu The MTU to use. Note that this is the local MTU. Upon opening the channel,
/// the final MTU will be negotiated to be the minimum of local and remote.
/// @param[in] callbacks The callbacks to use. NOTE that these callbacks are called from the
/// context of the NimBLE bluetooth task (`nimble_host`) and MUST be handled as fast as possible.
/// @return True if the channel was opened successfully, false otherwise.
static NimBLEL2CAPChannel* connect(NimBLEClient* client, uint16_t psm, uint16_t mtu, NimBLEL2CAPChannelCallbacks* callbacks);
/// @brief Write data to the channel.
///
/// If the size of the data exceeds the MTU, the data will be split into multiple fragments.
/// @return true on success, after the data has been sent.
/// @return false, if the data can't be sent.
///
/// NOTE: This function will block until the data has been sent or an error occurred.
bool write(const std::vector<uint8_t>& bytes);
/// @return True, if the channel is connected. False, otherwise.
bool isConnected() const { return !!channel; }
protected:
NimBLEL2CAPChannel(uint16_t psm, uint16_t mtu, NimBLEL2CAPChannelCallbacks* callbacks);
~NimBLEL2CAPChannel();
int handleConnectionEvent(struct ble_l2cap_event* event);
int handleAcceptEvent(struct ble_l2cap_event* event);
int handleDataReceivedEvent(struct ble_l2cap_event* event);
int handleTxUnstalledEvent(struct ble_l2cap_event* event);
int handleDisconnectionEvent(struct ble_l2cap_event* event);
private:
friend class NimBLEL2CAPServer;
static constexpr const char* LOG_TAG = "NimBLEL2CAPChannel";
const uint16_t psm; // PSM of the channel
const uint16_t mtu; // The requested (local) MTU of the channel, might be larger than negotiated MTU
struct ble_l2cap_chan* channel = nullptr;
NimBLEL2CAPChannelCallbacks* callbacks;
uint8_t* receiveBuffer = nullptr; // buffers a full (local) MTU
// NimBLE memory pool
void* _coc_memory = nullptr;
struct os_mempool _coc_mempool;
struct os_mbuf_pool _coc_mbuf_pool;
// Runtime handling
std::atomic<bool> stalled{false};
NimBLETaskData* m_pTaskData{nullptr};
// Allocate / deallocate NimBLE memory pool
bool setupMemPool();
void teardownMemPool();
// Writes data up to the size of the negotiated MTU to the channel.
int writeFragment(std::vector<uint8_t>::const_iterator begin, std::vector<uint8_t>::const_iterator end);
// L2CAP event handler
static int handleL2capEvent(struct ble_l2cap_event* event, void* arg);
};
/**
* @brief Callbacks base class for the L2CAP channel.
*/
class NimBLEL2CAPChannelCallbacks {
public:
NimBLEL2CAPChannelCallbacks() = default;
virtual ~NimBLEL2CAPChannelCallbacks() = default;
/// Called when the client attempts to open a channel on the server.
/// You can choose to accept or deny the connection.
/// Default implementation returns true.
virtual bool shouldAcceptConnection(NimBLEL2CAPChannel* channel) { return true; }
/// Called after a connection has been made.
/// Default implementation does nothing.
virtual void onConnect(NimBLEL2CAPChannel* channel, uint16_t negotiatedMTU) {};
/// Called when data has been read from the channel.
/// Default implementation does nothing.
virtual void onRead(NimBLEL2CAPChannel* channel, std::vector<uint8_t>& data) {};
/// Called after the channel has been disconnected.
/// Default implementation does nothing.
virtual void onDisconnect(NimBLEL2CAPChannel* channel) {};
};
#endif // CONFIG_BT_ENABLED && CONFIG_BT_NIMBLE_L2CAP_COC_MAX_NUM
#endif // NIMBLE_CPP_L2CAPCHANNEL_H_