Introduce L2CAP infrastructure. (#954)

Author: h2zero

examples/L2CAP/L2CAP_Client/L2CAP_Client.ino

@@ -0,0 +1,143 @@
+//
+// (C) Dr. Michael 'Mickey' Lauer <mickey@vanille-media.de>
+//
+
+#include <Arduino.h>
+#include <NimBLEDevice.h>
+
+#if CONFIG_BT_NIMBLE_L2CAP_COC_MAX_NUM <= 0
+# error "CONFIG_BT_NIMBLE_L2CAP_COC_MAX_NUM must be set to 1 or greater"
+#endif
+
+// See the following for generating UUIDs:
+// https://www.uuidgenerator.net/
+
+// The remote service we wish to connect to.
+static NimBLEUUID serviceUUID("dcbc7255-1e9e-49a0-a360-b0430b6c6905");
+// The characteristic of the remote service we are interested in.
+static NimBLEUUID charUUID("371a55c8-f251-4ad2-90b3-c7c195b049be");
+
+#define L2CAP_CHANNEL 150
+#define L2CAP_MTU     5000
+
+const NimBLEAdvertisedDevice* theDevice  = NULL;
+NimBLEClient*                 theClient  = NULL;
+NimBLEL2CAPChannel*           theChannel = NULL;
+
+size_t bytesSent       = 0;
+size_t bytesReceived   = 0;
+size_t numberOfSeconds = 0;
+
+class L2CAPChannelCallbacks : public NimBLEL2CAPChannelCallbacks {
+  public:
+    void onConnect(NimBLEL2CAPChannel* channel) { Serial.println("L2CAP connection established"); }
+
+    void onMTUChange(NimBLEL2CAPChannel* channel, uint16_t mtu) { Serial.printf("L2CAP MTU changed to %d\n", mtu); }
+
+    void onRead(NimBLEL2CAPChannel* channel, std::vector<uint8_t>& data) {
+        Serial.printf("L2CAP read %d bytes\n", data.size());
+    }
+    void onDisconnect(NimBLEL2CAPChannel* channel) { Serial.println("L2CAP disconnected"); }
+} L2Callbacks;
+
+class ClientCallbacks : public NimBLEClientCallbacks {
+    void onConnect(NimBLEClient* pClient) {
+        Serial.println("GAP connected");
+        pClient->setDataLen(251);
+
+        theChannel = NimBLEL2CAPChannel::connect(pClient, L2CAP_CHANNEL, L2CAP_MTU, &L2Callbacks);
+    }
+
+    void onDisconnect(NimBLEClient* pClient, int reason) {
+        printf("GAP disconnected (reason: %d)\n", reason);
+        theDevice  = NULL;
+        theChannel = NULL;
+        NimBLEDevice::getScan()->start(5 * 1000, true);
+    }
+} clientCallbacks;
+
+class ScanCallbacks : public NimBLEScanCallbacks {
+    void onResult(const NimBLEAdvertisedDevice* advertisedDevice) {
+        if (theDevice) {
+            return;
+        }
+        Serial.printf("BLE Advertised Device found: %s\n", advertisedDevice->toString().c_str());
+
+        if (!advertisedDevice->haveServiceUUID()) {
+            return;
+        }
+        if (!advertisedDevice->isAdvertisingService(serviceUUID)) {
+            return;
+        }
+
+        Serial.println("Found the device we're interested in!");
+        NimBLEDevice::getScan()->stop();
+
+        // Hand over the device to the other task
+        theDevice = advertisedDevice;
+    }
+} scanCallbacks;
+
+void setup() {
+    Serial.begin(115200);
+    Serial.println("Starting L2CAP client example");
+
+    NimBLEDevice::init("L2CAP-Client");
+    NimBLEDevice::setMTU(BLE_ATT_MTU_MAX);
+
+    auto scan = NimBLEDevice::getScan();
+    scan->setScanCallbacks(&scanCallbacks);
+    scan->setInterval(1349);
+    scan->setWindow(449);
+    scan->setActiveScan(true);
+    scan->start(25 * 1000, false);
+}
+
+void loop() {
+    static uint8_t       sequenceNumber = 0;
+    static unsigned long firstBytesTime = 0;
+    auto                 now            = millis();
+
+    if (!theDevice) {
+        delay(1000);
+        return;
+    }
+
+    if (!theClient) {
+        theClient = NimBLEDevice::createClient();
+        theClient->setConnectionParams(6, 6, 0, 42);
+        theClient->setClientCallbacks(&clientCallbacks);
+        if (!theClient->connect(theDevice)) {
+            Serial.println("Error: Could not connect to device");
+            return;
+        }
+        delay(2000);
+    }
+
+    if (!theChannel) {
+        Serial.println("l2cap channel not initialized");
+        delay(2000);
+        return;
+    }
+
+    if (!theChannel->isConnected()) {
+        Serial.println("l2cap channel not connected\n");
+        delay(2000);
+        return;
+    }
+
+    std::vector<uint8_t> data(5000, sequenceNumber++);
+    if (theChannel->write(data)) {
+        if (bytesSent == 0) {
+            firstBytesTime = now;
+        }
+        bytesSent += data.size();
+        if (now - firstBytesTime > 1000) {
+            int bytesSentPerSeconds = bytesSent / ((now - firstBytesTime) / 1000);
+            printf("Bandwidth: %d b/sec = %d KB/sec\n", bytesSentPerSeconds, bytesSentPerSeconds / 1024);
+        }
+    } else {
+        Serial.println("failed to send!");
+        abort();
+    }
+}

examples/L2CAP/L2CAP_Server/L2CAP_Server.ino

@@ -0,0 +1,97 @@
+//
+// (C) Dr. Michael 'Mickey' Lauer <mickey@vanille-media.de>
+//
+
+#include <Arduino.h>
+#include <NimBLEDevice.h>
+
+// See the following for generating UUIDs:
+// https://www.uuidgenerator.net/
+
+#define SERVICE_UUID        "dcbc7255-1e9e-49a0-a360-b0430b6c6905"
+#define CHARACTERISTIC_UUID "371a55c8-f251-4ad2-90b3-c7c195b049be"
+#define L2CAP_CHANNEL       150
+#define L2CAP_MTU           5000
+
+class GATTCallbacks : public NimBLEServerCallbacks {
+  public:
+    void onConnect(NimBLEServer* pServer, NimBLEConnInfo& info) {
+        /// Booster #1
+        pServer->setDataLen(info.getConnHandle(), 251);
+        /// Booster #2 (especially for Apple devices)
+        NimBLEDevice::getServer()->updateConnParams(info.getConnHandle(), 12, 12, 0, 200);
+    }
+} gattCallbacks;
+
+class L2CAPChannelCallbacks : public NimBLEL2CAPChannelCallbacks {
+  public:
+    bool    connected = false;
+    size_t  numberOfReceivedBytes;
+    uint8_t nextSequenceNumber;
+    int     numberOfSeconds;
+
+  public:
+    void onConnect(NimBLEL2CAPChannel* channel) {
+        Serial.println("L2CAP connection established");
+        connected       = true;
+        numberOfSeconds = numberOfReceivedBytes = nextSequenceNumber = 0;
+    }
+
+    void onRead(NimBLEL2CAPChannel* channel, std::vector<uint8_t>& data) {
+        numberOfReceivedBytes += data.size();
+        size_t sequenceNumber  = data[0];
+        Serial.printf("L2CAP read %d bytes w/ sequence number %d", data.size(), sequenceNumber);
+        if (sequenceNumber != nextSequenceNumber) {
+            Serial.printf("(wrong sequence number %d, expected %d)\n", sequenceNumber, nextSequenceNumber);
+        } else {
+            nextSequenceNumber++;
+        }
+    }
+
+    void onDisconnect(NimBLEL2CAPChannel* channel) {
+        Serial.println("L2CAP disconnected");
+        connected             = false;
+    }
+} l2capCallbacks;
+
+void setup() {
+    Serial.begin(115200);
+    Serial.println("Starting L2CAP server example");
+
+    NimBLEDevice::init("L2CAP-Server");
+    NimBLEDevice::setMTU(BLE_ATT_MTU_MAX);
+
+    auto cocServer = NimBLEDevice::createL2CAPServer();
+    auto channel   = cocServer->createService(L2CAP_CHANNEL, L2CAP_MTU, &l2capCallbacks);
+
+    auto server = NimBLEDevice::createServer();
+    server->setCallbacks(&gattCallbacks);
+
+    auto service        = server->createService(SERVICE_UUID);
+    auto characteristic = service->createCharacteristic(CHARACTERISTIC_UUID, NIMBLE_PROPERTY::READ);
+    characteristic->setValue(L2CAP_CHANNEL);
+    service->start();
+
+    auto advertising = BLEDevice::getAdvertising();
+    advertising->addServiceUUID(SERVICE_UUID);
+    advertising->enableScanResponse(true);
+
+    NimBLEDevice::startAdvertising();
+    Serial.println("Server waiting for connection requests");
+}
+
+void loop() {
+    // Wait until transfer actually starts...
+    if (!l2capCallbacks.numberOfReceivedBytes) {
+        delay(10);
+        return;
+    }
+
+    delay(1000);
+    if (!l2capCallbacks.connected) {
+        return;
+    }
+
+    int bps = l2capCallbacks.numberOfReceivedBytes / ++l2capCallbacks.numberOfSeconds;
+    Serial.printf("Bandwidth: %d b/sec = %d KB/sec\n", bps, bps / 1024);
+}

src/NimBLEDevice.cpp

@@ -65,6 +65,9 @@
 
 # if defined(CONFIG_BT_NIMBLE_ROLE_PERIPHERAL)
 #  include "NimBLEServer.h"
+#  if CONFIG_BT_NIMBLE_L2CAP_COC_MAX_NUM > 0
+#  include "NimBLEL2CAPServer.h"
+#  endif
 # endif
 
 # include "NimBLELog.h"
@@ -85,6 +88,9 @@ NimBLEScan* NimBLEDevice::m_pScan = nullptr;
 
 # if defined(CONFIG_BT_NIMBLE_ROLE_PERIPHERAL)
 NimBLEServer* NimBLEDevice::m_pServer = nullptr;
+#  if CONFIG_BT_NIMBLE_L2CAP_COC_MAX_NUM > 0
+NimBLEL2CAPServer* NimBLEDevice::m_pL2CAPServer = nullptr;
+#  endif
 # endif
 
 # if defined(CONFIG_BT_NIMBLE_ROLE_BROADCASTER)
@@ -140,6 +146,27 @@ NimBLEServer* NimBLEDevice::createServer() {
 NimBLEServer* NimBLEDevice::getServer() {
     return m_pServer;
 } // getServer
+
+#  if CONFIG_BT_NIMBLE_L2CAP_COC_MAX_NUM > 0
+/**
+ * @brief Create an instance of a L2CAP server.
+ * @return A pointer to the instance of the L2CAP server.
+ */
+NimBLEL2CAPServer* NimBLEDevice::createL2CAPServer() {
+    if (NimBLEDevice::m_pL2CAPServer == nullptr) {
+        NimBLEDevice::m_pL2CAPServer = new NimBLEL2CAPServer();
+    }
+    return m_pL2CAPServer;
+} // createL2CAPServer
+
+/**
+ * @brief Get the instance of the L2CAP server.
+ * @return A pointer to the L2CAP server instance or nullptr if none have been created.
+ */
+NimBLEL2CAPServer* NimBLEDevice::getL2CAPServer() {
+    return m_pL2CAPServer;
+} // getL2CAPServer
+#  endif
 # endif // #if defined(CONFIG_BT_NIMBLE_ROLE_PERIPHERAL)
 
 /* -------------------------------------------------------------------------- */
@@ -965,6 +992,12 @@ bool NimBLEDevice::deinit(bool clearAll) {
             delete NimBLEDevice::m_pServer;
             NimBLEDevice::m_pServer = nullptr;
         }
+#  if CONFIG_BT_NIMBLE_L2CAP_COC_MAX_NUM > 0
+        if (NimBLEDevice::m_pL2CAPServer != nullptr) {
+            delete NimBLEDevice::m_pL2CAPServer;
+            NimBLEDevice::m_pL2CAPServer = nullptr;
+        }
+#  endif
 # endif
 
 # if defined(CONFIG_BT_NIMBLE_ROLE_BROADCASTER)

src/NimBLEDevice.h

@@ -59,6 +59,9 @@ class NimBLEAdvertising;
 
 # if defined(CONFIG_BT_NIMBLE_ROLE_PERIPHERAL)
 class NimBLEServer;
+#  if CONFIG_BT_NIMBLE_L2CAP_COC_MAX_NUM > 0
+class NimBLEL2CAPServer;
+#  endif
 # endif
 
 # if defined(CONFIG_BT_NIMBLE_ROLE_PERIPHERAL) || defined(CONFIG_BT_NIMBLE_ROLE_CENTRAL)
@@ -95,6 +98,13 @@ class NimBLEDeviceCallbacks;
 # define BLEEddystoneTLM              NimBLEEddystoneTLM
 # define BLEEddystoneURL              NimBLEEddystoneURL
 # define BLEConnInfo                  NimBLEConnInfo
+# define BLEL2CAPServer               NimBLEL2CAPServer
+# define BLEL2CAPService              NimBLEL2CAPService
+# define BLEL2CAPServiceCallbacks     NimBLEL2CAPServiceCallbacks
+# define BLEL2CAPClient               NimBLEL2CAPClient
+# define BLEL2CAPClientCallbacks      NimBLEL2CAPClientCallbacks
+# define BLEL2CAPChannel              NimBLEL2CAPChannel
+# define BLEL2CAPChannelCallbacks     NimBLEL2CAPChannelCallbacks
 
 # ifdef CONFIG_BT_NIMBLE_MAX_CONNECTIONS
 #  define NIMBLE_MAX_CONNECTIONS CONFIG_BT_NIMBLE_MAX_CONNECTIONS
@@ -160,6 +170,10 @@ class NimBLEDevice {
 # if defined(CONFIG_BT_NIMBLE_ROLE_PERIPHERAL)
     static NimBLEServer* createServer();
     static NimBLEServer* getServer();
+#  if CONFIG_BT_NIMBLE_L2CAP_COC_MAX_NUM > 0
+    static NimBLEL2CAPServer* createL2CAPServer();
+    static NimBLEL2CAPServer* getL2CAPServer();
+#  endif
 # endif
 
 # if defined(CONFIG_BT_NIMBLE_ROLE_PERIPHERAL) || defined(CONFIG_BT_NIMBLE_ROLE_CENTRAL)
@@ -216,6 +230,9 @@ class NimBLEDevice {
 
 # if defined(CONFIG_BT_NIMBLE_ROLE_PERIPHERAL)
     static NimBLEServer* m_pServer;
+#  if CONFIG_BT_NIMBLE_L2CAP_COC_MAX_NUM > 0
+    static NimBLEL2CAPServer* m_pL2CAPServer;
+#  endif
 # endif
 
 # if defined(CONFIG_BT_NIMBLE_ROLE_BROADCASTER)
@@ -275,6 +292,10 @@ class NimBLEDevice {
 #  include "NimBLEService.h"
 #  include "NimBLECharacteristic.h"
 #  include "NimBLEDescriptor.h"
+#  if CONFIG_BT_NIMBLE_L2CAP_COC_MAX_NUM > 0
+#   include "NimBLEL2CAPServer.h"
+#   include "NimBLEL2CAPChannel.h"
+#  endif
 # endif
 
 # if defined(CONFIG_BT_NIMBLE_ROLE_BROADCASTER)