Merge pull request #454 from jbrazio/jbrazio/2025_3f11ad35

RS232/ESP-NOW Bridge/cross repeater implementation

Author: fdlamotte

examples/simple_repeater/main.cpp

@@ -78,28 +78,38 @@
 
 /* ------------------------------ Code -------------------------------- */
 
-#define REQ_TYPE_GET_STATUS          0x01   // same as _GET_STATS
-#define REQ_TYPE_KEEP_ALIVE          0x02
-#define REQ_TYPE_GET_TELEMETRY_DATA  0x03
-
-#define RESP_SERVER_LOGIN_OK      0   // response to ANON_REQ
-
-struct RepeaterStats {
-  uint16_t batt_milli_volts;
-  uint16_t curr_tx_queue_len;
-  int16_t  noise_floor;
-  int16_t  last_rssi;
-  uint32_t n_packets_recv;
-  uint32_t n_packets_sent;
-  uint32_t total_air_time_secs;
-  uint32_t total_up_time_secs;
-  uint32_t n_sent_flood, n_sent_direct;
-  uint32_t n_recv_flood, n_recv_direct;
-  uint16_t err_events;                // was 'n_full_events'
-  int16_t  last_snr;   // x 4
-  uint16_t n_direct_dups, n_flood_dups;
-  uint32_t total_rx_air_time_secs;
-};
+#ifdef WITH_RS232_BRIDGE
+#include "helpers/bridges/RS232Bridge.h"
+#define WITH_BRIDGE
+#endif
+
+#ifdef WITH_ESPNOW_BRIDGE
+#include "helpers/bridges/ESPNowBridge.h"
+#define WITH_BRIDGE
+#endif
+
+#define REQ_TYPE_GET_STATUS         0x01 // same as _GET_STATS
+#define REQ_TYPE_KEEP_ALIVE         0x02
+#define REQ_TYPE_GET_TELEMETRY_DATA 0x03
+
+#define RESP_SERVER_LOGIN_OK        0 // response to ANON_REQ
+
+  struct RepeaterStats {
+    uint16_t batt_milli_volts;
+    uint16_t curr_tx_queue_len;
+    int16_t noise_floor;
+    int16_t last_rssi;
+    uint32_t n_packets_recv;
+    uint32_t n_packets_sent;
+    uint32_t total_air_time_secs;
+    uint32_t total_up_time_secs;
+    uint32_t n_sent_flood, n_sent_direct;
+    uint32_t n_recv_flood, n_recv_direct;
+    uint16_t err_events; // was 'n_full_events'
+    int16_t last_snr;    // x 4
+    uint16_t n_direct_dups, n_flood_dups;
+    uint32_t total_rx_air_time_secs;
+  };
 
 struct ClientInfo {
   mesh::Identity id;
@@ -114,6 +124,10 @@ struct ClientInfo {
   #define MAX_CLIENTS           32
 #endif
 
+#ifdef WITH_BRIDGE
+AbstractBridge* bridge;
+#endif
+
 struct NeighbourInfo {
   mesh::Identity id;
   uint32_t advert_timestamp;
@@ -300,6 +314,9 @@ class MyMesh : public mesh::Mesh, public CommonCLICallbacks {
     }
   }
   void logTx(mesh::Packet* pkt, int len) override {
+#ifdef WITH_BRIDGE
+    bridge->onPacketTransmitted(pkt);
+#endif
     if (_logging) {
       File f = openAppend(PACKET_LOG_FILE);
       if (f) {
@@ -364,9 +381,9 @@ class MyMesh : public mesh::Mesh, public CommonCLICallbacks {
       } else if (strcmp((char *) &data[4], _prefs.guest_password) == 0) {  // check guest password
         is_admin = false;
       } else {
-    #if MESH_DEBUG
+#if MESH_DEBUG
         MESH_DEBUG_PRINTLN("Invalid password: %s", &data[4]);
-    #endif
+#endif
         return;
       }
 
@@ -384,15 +401,15 @@ class MyMesh : public mesh::Mesh, public CommonCLICallbacks {
 
       uint32_t now = getRTCClock()->getCurrentTimeUnique();
       memcpy(reply_data, &now, 4);   // response packets always prefixed with timestamp
-    #if 0
+#if 0
       memcpy(&reply_data[4], "OK", 2);   // legacy response
-    #else
+#else
       reply_data[4] = RESP_SERVER_LOGIN_OK;
       reply_data[5] = 0;  // NEW: recommended keep-alive interval (secs / 16)
       reply_data[6] = is_admin ? 1 : 0;
       reply_data[7] = 0;  // FUTURE: reserved
       getRNG()->random(&reply_data[8], 4);   // random blob to help packet-hash uniqueness
-  #endif
+#endif
 
       if (packet->isRouteFlood()) {
         // let this sender know path TO here, so they can use sendDirect(), and ALSO encode the response
@@ -565,14 +582,23 @@ class MyMesh : public mesh::Mesh, public CommonCLICallbacks {
      : mesh::Mesh(radio, ms, rng, rtc, *new StaticPoolPacketManager(32), tables),
       _cli(board, rtc, &_prefs, this), telemetry(MAX_PACKET_PAYLOAD - 4)
   {
+#ifdef WITH_BRIDGE
+#if defined(WITH_RS232_BRIDGE)
+    bridge = new RS232Bridge(WITH_RS232_BRIDGE, _mgr, &rtc);
+#elif defined(WITH_ESPNOW_BRIDGE)
+    bridge = new ESPNowBridge(_mgr, &rtc);
+#else
+#error "You must choose either RS232 or ESPNow bridge"
+#endif
+#endif
     memset(known_clients, 0, sizeof(known_clients));
     next_local_advert = next_flood_advert = 0;
     set_radio_at = revert_radio_at = 0;
     _logging = false;
 
-  #if MAX_NEIGHBOURS
+#if MAX_NEIGHBOURS
     memset(neighbours, 0, sizeof(neighbours));
-  #endif
+#endif
 
     // defaults
     memset(&_prefs, 0, sizeof(_prefs));
@@ -765,6 +791,10 @@ class MyMesh : public mesh::Mesh, public CommonCLICallbacks {
   }
 
   void loop() {
+#ifdef WITH_BRIDGE
+    bridge->loop();
+#endif
+
     mesh::Mesh::loop();
 
     if (next_flood_advert && millisHasNowPassed(next_flood_advert)) {
@@ -813,6 +843,10 @@ void setup() {
   Serial.begin(115200);
   delay(1000);
 
+#ifdef WITH_BRIDGE
+  bridge->begin();
+#endif
+
   board.begin();
 
 #ifdef DISPLAY_CLASS
@@ -824,7 +858,9 @@ void setup() {
   }
 #endif
 
-  if (!radio_init()) { halt(); }
+  if (!radio_init()) {
+    halt();
+  }
 
   fast_rng.begin(radio_get_rng_seed());
 

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/AbstractBridge.h

@@ -0,0 +1,34 @@
+#pragma once
+
+#include <Mesh.h>
+
+class AbstractBridge {
+public:
+  virtual ~AbstractBridge() {}
+
+  /**
+   * @brief Initializes the bridge.
+   */
+  virtual void begin() = 0;
+
+  /**
+   * @brief A method to be called on every main loop iteration.
+   *        Used for tasks like checking for incoming data.
+   */
+  virtual void loop() = 0;
+
+  /**
+   * @brief A callback that is triggered when the mesh transmits a packet.
+   *        The bridge can use this to forward the packet.
+   * 
+   * @param packet The packet that was transmitted.
+   */
+  virtual void onPacketTransmitted(mesh::Packet* packet) = 0;
+
+  /**
+   * @brief Processes a received packet from the bridge's medium.
+   * 
+   * @param packet The packet that was received.
+   */
+  virtual void onPacketReceived(mesh::Packet* packet) = 0;
+};

src/helpers/bridges/BridgeBase.cpp

@@ -0,0 +1,36 @@
+#include "BridgeBase.h"
+
+#include <Arduino.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, millis() + BRIDGE_DELAY);
+  } else {
+    _mgr->free(packet);
+  }
+}

src/helpers/bridges/BridgeBase.h

@@ -0,0 +1,112 @@
+#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;
+
+  /**
+   * @brief Common magic number used by all bridge implementations for packet identification
+   *
+   * This magic number is placed at the beginning of bridge packets to identify
+   * them as mesh bridge packets and provide frame synchronization.
+   */
+  static constexpr uint16_t BRIDGE_PACKET_MAGIC = 0xC03E;
+
+  /**
+   * @brief Common field sizes used by bridge implementations
+   *
+   * These constants define the size of common packet fields used across bridges.
+   * BRIDGE_MAGIC_SIZE is used by all bridges for packet identification.
+   * BRIDGE_LENGTH_SIZE is used by bridges that need explicit length fields (like RS232).
+   * BRIDGE_CHECKSUM_SIZE is used by all bridges for Fletcher-16 checksums.
+   */
+  static constexpr uint16_t BRIDGE_MAGIC_SIZE = sizeof(BRIDGE_PACKET_MAGIC);
+  static constexpr uint16_t BRIDGE_LENGTH_SIZE = sizeof(uint16_t);
+  static constexpr uint16_t BRIDGE_CHECKSUM_SIZE = sizeof(uint16_t);
+
+  /**
+   * @brief Default delay in milliseconds for scheduling inbound packet processing
+   *
+   * It provides a buffer to prevent immediate processing conflicts in the mesh network.
+   * Used in handleReceivedPacket() as: millis() + BRIDGE_DELAY
+   */
+  static constexpr uint16_t BRIDGE_DELAY = 500; // TODO: maybe too high ?
+
+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);
+};