Refactor bridge implementations to inherit from BridgeBase

Author: jbrazio

platformio.ini

@@ -47,6 +47,7 @@ build_src_filter =
   +<*.cpp>
   +<helpers/*.cpp>
   +<helpers/radiolib/*.cpp>
+  +<helpers/bridges/BridgeBase.cpp>
   +<helpers/ui/MomentaryButton.cpp>
 
 ; ----------------- ESP32 ---------------------

src/helpers/bridges/BridgeBase.cpp

@@ -0,0 +1,34 @@
+#include "BridgeBase.h"
+
+const char *BridgeBase::getLogDateTime() {
+  static char tmp[32];
+  uint32_t now = _rtc->getCurrentTime();
+  DateTime dt = DateTime(now);
+  sprintf(tmp, "%02d:%02d:%02d - %d/%d/%d U", dt.hour(), dt.minute(), dt.second(), dt.day(), dt.month(),
+          dt.year());
+  return tmp;
+}
+
+uint16_t BridgeBase::fletcher16(const uint8_t *data, size_t len) {
+  uint8_t sum1 = 0, sum2 = 0;
+
+  for (size_t i = 0; i < len; i++) {
+    sum1 = (sum1 + data[i]) % 255;
+    sum2 = (sum2 + sum1) % 255;
+  }
+
+  return (sum2 << 8) | sum1;
+}
+
+bool BridgeBase::validateChecksum(const uint8_t *data, size_t len, uint16_t received_checksum) {
+  uint16_t calculated_checksum = fletcher16(data, len);
+  return received_checksum == calculated_checksum;
+}
+
+void BridgeBase::handleReceivedPacket(mesh::Packet *packet) {
+  if (!_seen_packets.hasSeen(packet)) {
+    _mgr->queueInbound(packet, 0);
+  } else {
+    _mgr->free(packet);
+  }
+}

src/helpers/bridges/BridgeBase.h

@@ -0,0 +1,84 @@
+#pragma once
+
+#include "helpers/AbstractBridge.h"
+#include "helpers/SimpleMeshTables.h"
+
+#include <RTClib.h>
+
+/**
+ * @brief Base class implementing common bridge functionality
+ *
+ * This class provides common functionality used by different bridge implementations
+ * like packet tracking, checksum calculation, timestamping, and duplicate detection.
+ *
+ * Features:
+ * - Fletcher-16 checksum calculation for data integrity
+ * - Packet duplicate detection using SimpleMeshTables
+ * - Common timestamp formatting for debug logging
+ * - Shared packet management and queuing logic
+ */
+class BridgeBase : public AbstractBridge {
+public:
+  virtual ~BridgeBase() = default;
+
+protected:
+  /** Packet manager for allocating and queuing mesh packets */
+  mesh::PacketManager *_mgr;
+
+  /** RTC clock for timestamping debug messages */
+  mesh::RTCClock *_rtc;
+
+  /** Tracks seen packets to prevent loops in broadcast communications */
+  SimpleMeshTables _seen_packets;
+
+  /**
+   * @brief Constructs a BridgeBase instance
+   *
+   * @param mgr PacketManager for allocating and queuing packets
+   * @param rtc RTCClock for timestamping debug messages
+   */
+  BridgeBase(mesh::PacketManager *mgr, mesh::RTCClock *rtc) : _mgr(mgr), _rtc(rtc) {}
+
+  /**
+   * @brief Gets formatted date/time string for logging
+   *
+   * Format: "HH:MM:SS - DD/MM/YYYY U"
+   *
+   * @return Formatted date/time string
+   */
+  const char *getLogDateTime();
+
+  /**
+   * @brief Calculate Fletcher-16 checksum
+   *
+   * Based on: https://en.wikipedia.org/wiki/Fletcher%27s_checksum
+   * Used to verify data integrity of received packets
+   *
+   * @param data Pointer to data to calculate checksum for
+   * @param len Length of data in bytes
+   * @return Calculated Fletcher-16 checksum
+   */
+  static uint16_t fletcher16(const uint8_t *data, size_t len);
+
+  /**
+   * @brief Validate received checksum against calculated checksum
+   *
+   * @param data Pointer to data to validate
+   * @param len Length of data in bytes
+   * @param received_checksum Checksum received with data
+   * @return true if checksum is valid, false otherwise
+   */
+  bool validateChecksum(const uint8_t *data, size_t len, uint16_t received_checksum);
+
+  /**
+   * @brief Common packet handling for received packets
+   *
+   * Implements the standard pattern used by all bridges:
+   * - Check if packet was seen before using _seen_packets.hasSeen()
+   * - Queue packet for mesh processing if not seen before
+   * - Free packet if already seen to prevent duplicates
+   *
+   * @param packet The received mesh packet
+   */
+  void handleReceivedPacket(mesh::Packet *packet);
+};

src/helpers/bridges/ESPNowBridge.cpp

@@ -1,6 +1,5 @@
 #include "ESPNowBridge.h"
 
-#include <RTClib.h>
 #include <WiFi.h>
 #include <esp_wifi.h>
 
@@ -22,21 +21,8 @@ void ESPNowBridge::send_cb(const uint8_t *mac, esp_now_send_status_t status) {
   }
 }
 
-// Fletcher16 checksum calculation
-static uint16_t fletcher16(const uint8_t *data, size_t len) {
-  uint16_t sum1 = 0;
-  uint16_t sum2 = 0;
-
-  while (len--) {
-    sum1 = (sum1 + *data++) % 255;
-    sum2 = (sum2 + sum1) % 255;
-  }
-
-  return (sum2 << 8) | sum1;
-}
-
 ESPNowBridge::ESPNowBridge(mesh::PacketManager *mgr, mesh::RTCClock *rtc)
-    : _mgr(mgr), _rtc(rtc), _rx_buffer_pos(0) {
+    : BridgeBase(mgr, rtc), _rx_buffer_pos(0) {
   _instance = this;
 }
 
@@ -115,13 +101,12 @@ void ESPNowBridge::onDataRecv(const uint8_t *mac, const uint8_t *data, int32_t l
   // Validate checksum
   uint16_t received_checksum = (decrypted[0] << 8) | decrypted[1];
   const size_t payloadLen = encryptedDataLen - CHECKSUM_SIZE;
-  uint16_t calculated_checksum = fletcher16(decrypted + CHECKSUM_SIZE, payloadLen);
 
-  if (received_checksum != calculated_checksum) {
+  if (!validateChecksum(decrypted + CHECKSUM_SIZE, payloadLen, received_checksum)) {
     // Failed to decrypt - likely from a different network
 #if MESH_PACKET_LOGGING
-    Serial.printf("%s: ESPNOW BRIDGE: RX checksum mismatch, rcv=0x%04X calc=0x%04X\n", getLogDateTime(),
-                  received_checksum, calculated_checksum);
+    Serial.printf("%s: ESPNOW BRIDGE: RX checksum mismatch, rcv=0x%04X\n", getLogDateTime(),
+                  received_checksum);
 #endif
     return;
   }
@@ -146,23 +131,19 @@ void ESPNowBridge::onDataSent(const uint8_t *mac_addr, esp_now_send_status_t sta
 }
 
 void ESPNowBridge::onPacketReceived(mesh::Packet *packet) {
-  if (!_seen_packets.hasSeen(packet)) {
-    _mgr->queueInbound(packet, 0);
-  } else {
-    _mgr->free(packet);
-  }
+  handleReceivedPacket(packet);
 }
 
 void ESPNowBridge::onPacketTransmitted(mesh::Packet *packet) {
-  if (!_seen_packets.hasSeen(packet)) {
-
-    // First validate the packet pointer
-    if (!packet) {
+  // First validate the packet pointer
+  if (!packet) {
 #if MESH_PACKET_LOGGING
-      Serial.printf("%s: ESPNOW BRIDGE: TX invalid packet pointer\n", getLogDateTime());
+    Serial.printf("%s: ESPNOW BRIDGE: TX invalid packet pointer\n", getLogDateTime());
 #endif
-      return;
-    }
+    return;
+  }
+
+  if (!_seen_packets.hasSeen(packet)) {
 
     // Create a temporary buffer just for size calculation and reuse for actual writing
     uint8_t sizingBuffer[MAX_PAYLOAD_SIZE];
@@ -212,13 +193,4 @@ void ESPNowBridge::onPacketTransmitted(mesh::Packet *packet) {
   }
 }
 
-const char *ESPNowBridge::getLogDateTime() {
-  static char tmp[32];
-  uint32_t now = _rtc->getCurrentTime();
-  DateTime dt = DateTime(now);
-  sprintf(tmp, "%02d:%02d:%02d - %d/%d/%d U", dt.hour(), dt.minute(), dt.second(), dt.day(), dt.month(),
-          dt.year());
-  return tmp;
-}
-
 #endif

src/helpers/bridges/ESPNowBridge.h

@@ -2,8 +2,7 @@
 
 #include "MeshCore.h"
 #include "esp_now.h"
-#include "helpers/AbstractBridge.h"
-#include "helpers/SimpleMeshTables.h"
+#include "helpers/bridges/BridgeBase.h"
 
 #ifdef WITH_ESPNOW_BRIDGE
 
@@ -44,21 +43,12 @@
  * WITH_ESPNOW_BRIDGE_SECRET values. Packets encrypted with a different key will
  * fail the checksum validation and be discarded.
  */
-class ESPNowBridge : public AbstractBridge {
+class ESPNowBridge : public BridgeBase {
 private:
   static ESPNowBridge *_instance;
   static void recv_cb(const uint8_t *mac, const uint8_t *data, int32_t len);
   static void send_cb(const uint8_t *mac, esp_now_send_status_t status);
 
-  /** Packet manager for allocating and queuing mesh packets */
-  mesh::PacketManager *_mgr;
-
-  /** RTC clock for timestamping debug messages */
-  mesh::RTCClock *_rtc;
-
-  /** Tracks seen packets to prevent loops in broadcast communications */
-  SimpleMeshTables _seen_packets;
-
   /**
    * ESP-NOW Protocol Structure:
    * - ESP-NOW header: 20 bytes (handled by ESP-NOW protocol)
@@ -168,14 +158,6 @@ class ESPNowBridge : public AbstractBridge {
    * @param packet The mesh packet to transmit
    */
   void onPacketTransmitted(mesh::Packet *packet) override;
-
-  /**
-   * Gets formatted date/time string for logging
-   * Format: "HH:MM:SS - DD/MM/YYYY U"
-   *
-   * @return Formatted date/time string
-   */
-  const char *getLogDateTime();
 };
 
 #endif