MeshCoreTel-firmware/examples/simple_repeater/main.cpp

#include <Arduino.h>   // needed for PlatformIO
#include <Mesh.h>

#if defined(NRF52_PLATFORM) || defined(STM32_PLATFORM)
  #include <InternalFileSystem.h>
#elif defined(RP2040_PLATFORM)
  #include <LittleFS.h>
#elif defined(ESP32)
  #include <SPIFFS.h>
#endif

#include <helpers/ArduinoHelpers.h>
#include <helpers/StaticPoolPacketManager.h>
#include <helpers/SimpleMeshTables.h>
#include <helpers/IdentityStore.h>
#include <helpers/AdvertDataHelpers.h>
#include <helpers/TxtDataHelpers.h>
#include <helpers/CommonCLI.h>
#include <RTClib.h>
#include <target.h>

/* ------------------------------ Config -------------------------------- */

#ifndef FIRMWARE_BUILD_DATE
  #define FIRMWARE_BUILD_DATE   "24 Jul 2025"
#endif

#ifndef FIRMWARE_VERSION
  #define FIRMWARE_VERSION   "v1.7.4"
#endif

#ifndef LORA_FREQ
  #define LORA_FREQ   915.0
#endif
#ifndef LORA_BW
  #define LORA_BW     250
#endif
#ifndef LORA_SF
  #define LORA_SF     10
#endif
#ifndef LORA_CR
  #define LORA_CR      5
#endif
#ifndef LORA_TX_POWER
  #define LORA_TX_POWER  20
#endif

#ifndef ADVERT_NAME
  #define  ADVERT_NAME   "repeater"
#endif
#ifndef ADVERT_LAT
  #define  ADVERT_LAT  0.0
#endif
#ifndef ADVERT_LON
  #define  ADVERT_LON  0.0
#endif

#ifndef ADMIN_PASSWORD
  #define  ADMIN_PASSWORD  "password"
#endif

#ifndef SERVER_RESPONSE_DELAY
  #define SERVER_RESPONSE_DELAY   300
#endif

#ifndef TXT_ACK_DELAY
  #define TXT_ACK_DELAY     200
#endif

#ifdef DISPLAY_CLASS
  #include "UITask.h"
  static UITask ui_task(display);
#endif

#define FIRMWARE_ROLE "repeater"

#define PACKET_LOG_FILE  "/packet_log"

/* ------------------------------ 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;
};

struct ClientInfo {
  mesh::Identity id;
  uint32_t last_timestamp, last_activity;
  uint8_t secret[PUB_KEY_SIZE];
  bool    is_admin;
  int8_t  out_path_len;
  uint8_t out_path[MAX_PATH_SIZE];
};

#ifndef MAX_CLIENTS
  #define MAX_CLIENTS           32
#endif

struct NeighbourInfo {
  mesh::Identity id;
  uint32_t advert_timestamp;
  uint32_t heard_timestamp;
  int8_t snr; // multiplied by 4, user should divide to get float value
};

#define CLI_REPLY_DELAY_MILLIS  600

class MyMesh : public mesh::Mesh, public CommonCLICallbacks {
  FILESYSTEM* _fs;
  unsigned long next_local_advert, next_flood_advert;
  bool _logging;
  NodePrefs _prefs;
  CommonCLI _cli;
  uint8_t reply_data[MAX_PACKET_PAYLOAD];
  ClientInfo known_clients[MAX_CLIENTS];
#if MAX_NEIGHBOURS
  NeighbourInfo neighbours[MAX_NEIGHBOURS];
#endif
  CayenneLPP telemetry;
  unsigned long set_radio_at, revert_radio_at;
  float pending_freq;
  float pending_bw;
  uint8_t pending_sf;
  uint8_t pending_cr;

  ClientInfo* putClient(const mesh::Identity& id) {
    uint32_t min_time = 0xFFFFFFFF;
    ClientInfo* oldest = &known_clients[0];
    for (int i = 0; i < MAX_CLIENTS; i++) {
      if (known_clients[i].last_activity < min_time) {
        oldest = &known_clients[i];
        min_time = oldest->last_activity;
      }
      if (id.matches(known_clients[i].id)) return &known_clients[i];  // already known
    }

    oldest->id = id;
    oldest->out_path_len = -1;  // initially out_path is unknown
    oldest->last_timestamp = 0;
    return oldest;
  }

  void putNeighbour(const mesh::Identity& id, uint32_t timestamp, float snr) {
  #if MAX_NEIGHBOURS    // check if neighbours enabled    
    // find existing neighbour, else use least recently updated
    uint32_t oldest_timestamp = 0xFFFFFFFF;
    NeighbourInfo* neighbour = &neighbours[0];
    for (int i = 0; i < MAX_NEIGHBOURS; i++) {
      // if neighbour already known, we should update it
      if (id.matches(neighbours[i].id)) {
        neighbour = &neighbours[i];
        break;
      }

      // otherwise we should update the least recently updated neighbour
      if (neighbours[i].heard_timestamp < oldest_timestamp) {
        neighbour = &neighbours[i];
        oldest_timestamp = neighbour->heard_timestamp;
      }
    }

    // update neighbour info
    neighbour->id = id;
    neighbour->advert_timestamp = timestamp;
    neighbour->heard_timestamp = getRTCClock()->getCurrentTime();
    neighbour->snr = (int8_t) (snr * 4);
  #endif
  }

  int handleRequest(ClientInfo* sender, uint32_t sender_timestamp, uint8_t* payload, size_t payload_len) {
   // uint32_t now = getRTCClock()->getCurrentTimeUnique();
   // memcpy(reply_data, &now, 4);   // response packets always prefixed with timestamp
    memcpy(reply_data, &sender_timestamp, 4);   // reflect sender_timestamp back in response packet (kind of like a 'tag')

    switch (payload[0]) {
      case REQ_TYPE_GET_STATUS: {   // guests can also access this now
        RepeaterStats stats;
        stats.batt_milli_volts = board.getBattMilliVolts();
        stats.curr_tx_queue_len = _mgr->getOutboundCount(0xFFFFFFFF);
        stats.noise_floor = (int16_t)_radio->getNoiseFloor();
        stats.last_rssi = (int16_t) radio_driver.getLastRSSI();
        stats.n_packets_recv = radio_driver.getPacketsRecv();
        stats.n_packets_sent = radio_driver.getPacketsSent();
        stats.total_air_time_secs = getTotalAirTime() / 1000;
        stats.total_up_time_secs = _ms->getMillis() / 1000;
        stats.n_sent_flood = getNumSentFlood();
        stats.n_sent_direct = getNumSentDirect();
        stats.n_recv_flood = getNumRecvFlood();
        stats.n_recv_direct = getNumRecvDirect();
        stats.err_events = _err_flags;
        stats.last_snr = (int16_t)(radio_driver.getLastSNR() * 4);
        stats.n_direct_dups = ((SimpleMeshTables *)getTables())->getNumDirectDups();
        stats.n_flood_dups = ((SimpleMeshTables *)getTables())->getNumFloodDups();
        stats.total_rx_air_time_secs = getReceiveAirTime() / 1000;

        memcpy(&reply_data[4], &stats, sizeof(stats));

        return 4 + sizeof(stats);  //  reply_len
      }
      case REQ_TYPE_GET_TELEMETRY_DATA: {
        uint8_t perm_mask = ~(payload[1]);    // NEW: first reserved byte (of 4), is now inverse mask to apply to permissions

        telemetry.reset();
        telemetry.addVoltage(TELEM_CHANNEL_SELF, (float)board.getBattMilliVolts() / 1000.0f);
        // query other sensors -- target specific
        sensors.querySensors((sender->is_admin ? 0xFF : 0x00) & perm_mask, telemetry);

        uint8_t tlen = telemetry.getSize();
        memcpy(&reply_data[4], telemetry.getBuffer(), tlen);
        return 4 + tlen;  // reply_len
      }
    }
    return 0;  // unknown command
  }

  mesh::Packet* createSelfAdvert() {
    uint8_t app_data[MAX_ADVERT_DATA_SIZE];
    uint8_t app_data_len;
    {
      AdvertDataBuilder builder(ADV_TYPE_REPEATER, _prefs.node_name, _prefs.node_lat, _prefs.node_lon);
      app_data_len = builder.encodeTo(app_data);
    }

   return createAdvert(self_id, app_data, app_data_len);
  }

  File openAppend(const char* fname) {
  #if defined(NRF52_PLATFORM) || defined(STM32_PLATFORM)
    return _fs->open(fname, FILE_O_WRITE);
  #elif defined(RP2040_PLATFORM)
    return _fs->open(fname, "a");
  #else
    return _fs->open(fname, "a", true);
  #endif
  }

protected:
  float getAirtimeBudgetFactor() const override {
    return _prefs.airtime_factor;
  }

  bool allowPacketForward(const mesh::Packet* packet) override {
    if (_prefs.disable_fwd) return false;
    if (packet->isRouteFlood() && packet->path_len >= _prefs.flood_max) return false;
    return true;
  }

  const char* getLogDateTime() override {
    static char tmp[32];
    uint32_t now = getRTCClock()->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;
  }

  void logRxRaw(float snr, float rssi, const uint8_t raw[], int len) override {
  #if MESH_PACKET_LOGGING
    Serial.print(getLogDateTime());
    Serial.print(" RAW: ");
    mesh::Utils::printHex(Serial, raw, len);
    Serial.println();
  #endif
  }

  void logRx(mesh::Packet* pkt, int len, float score) override {
    if (_logging) {
      File f = openAppend(PACKET_LOG_FILE);
      if (f) {
        f.print(getLogDateTime());
        f.printf(": RX, len=%d (type=%d, route=%s, payload_len=%d) SNR=%d RSSI=%d score=%d",
          len, pkt->getPayloadType(), pkt->isRouteDirect() ? "D" : "F", pkt->payload_len,
          (int)_radio->getLastSNR(), (int)_radio->getLastRSSI(), (int)(score*1000));

        if (pkt->getPayloadType() == PAYLOAD_TYPE_PATH || pkt->getPayloadType() == PAYLOAD_TYPE_REQ
          || pkt->getPayloadType() == PAYLOAD_TYPE_RESPONSE || pkt->getPayloadType() == PAYLOAD_TYPE_TXT_MSG) {
          f.printf(" [%02X -> %02X]\n", (uint32_t)pkt->payload[1], (uint32_t)pkt->payload[0]);
        } else {
          f.printf("\n");
        }
        f.close();
      }
    }
  }
  void logTx(mesh::Packet* pkt, int len) override {
    if (_logging) {
      File f = openAppend(PACKET_LOG_FILE);
      if (f) {
        f.print(getLogDateTime());
        f.printf(": TX, len=%d (type=%d, route=%s, payload_len=%d)",
          len, pkt->getPayloadType(), pkt->isRouteDirect() ? "D" : "F", pkt->payload_len);

        if (pkt->getPayloadType() == PAYLOAD_TYPE_PATH || pkt->getPayloadType() == PAYLOAD_TYPE_REQ
          || pkt->getPayloadType() == PAYLOAD_TYPE_RESPONSE || pkt->getPayloadType() == PAYLOAD_TYPE_TXT_MSG) {
          f.printf(" [%02X -> %02X]\n", (uint32_t)pkt->payload[1], (uint32_t)pkt->payload[0]);
        } else {
          f.printf("\n");
        }
        f.close();
      }
    }
  }
  void logTxFail(mesh::Packet* pkt, int len) override {
    if (_logging) {
      File f = openAppend(PACKET_LOG_FILE);
      if (f) {
        f.print(getLogDateTime());
        f.printf(": TX FAIL!, len=%d (type=%d, route=%s, payload_len=%d)\n",
          len, pkt->getPayloadType(), pkt->isRouteDirect() ? "D" : "F", pkt->payload_len);
        f.close();
      }
    }
  }

  int calcRxDelay(float score, uint32_t air_time) const override {
    if (_prefs.rx_delay_base <= 0.0f) return 0;
    return (int) ((pow(_prefs.rx_delay_base, 0.85f - score) - 1.0) * air_time);
  }

  uint32_t getRetransmitDelay(const mesh::Packet* packet) override {
    uint32_t t = (_radio->getEstAirtimeFor(packet->path_len + packet->payload_len + 2) * _prefs.tx_delay_factor);
    return getRNG()->nextInt(0, 6)*t;
  }
  uint32_t getDirectRetransmitDelay(const mesh::Packet* packet) override {
    uint32_t t = (_radio->getEstAirtimeFor(packet->path_len + packet->payload_len + 2) * _prefs.direct_tx_delay_factor);
    return getRNG()->nextInt(0, 6)*t;
  }
  int getInterferenceThreshold() const override {
    return _prefs.interference_threshold;
  }
  int getAGCResetInterval() const override {
    return ((int)_prefs.agc_reset_interval) * 4000;   // milliseconds
  }
  uint8_t getExtraAckTransmitCount() const override {
    return _prefs.multi_acks;
  }

  void onAnonDataRecv(mesh::Packet* packet, const uint8_t* secret, const mesh::Identity& sender, uint8_t* data, size_t len) override {
    if (packet->getPayloadType() == PAYLOAD_TYPE_ANON_REQ) {  // received an initial request by a possible admin client (unknown at this stage)
      uint32_t timestamp;
      memcpy(&timestamp, data, 4);

      bool is_admin;
      data[len] = 0;  // ensure null terminator
      if (strcmp((char *) &data[4], _prefs.password) == 0) {  // check for valid password
        is_admin = true;
      } else if (strcmp((char *) &data[4], _prefs.guest_password) == 0) {  // check guest password
        is_admin = false;
      } else {
    #if MESH_DEBUG
        MESH_DEBUG_PRINTLN("Invalid password: %s", &data[4]);
    #endif
        return;
      }

      auto client = putClient(sender);  // add to known clients (if not already known)
      if (timestamp <= client->last_timestamp) {
        MESH_DEBUG_PRINTLN("Possible login replay attack!");
        return;  // FATAL: client table is full -OR- replay attack
      }

      MESH_DEBUG_PRINTLN("Login success!");
      client->last_timestamp = timestamp;
      client->last_activity = getRTCClock()->getCurrentTime();
      client->is_admin = is_admin;
      memcpy(client->secret, secret, PUB_KEY_SIZE);

      uint32_t now = getRTCClock()->getCurrentTimeUnique();
      memcpy(reply_data, &now, 4);   // response packets always prefixed with timestamp
    #if 0
      memcpy(&reply_data[4], "OK", 2);   // legacy response
    #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

      if (packet->isRouteFlood()) {
        // let this sender know path TO here, so they can use sendDirect(), and ALSO encode the response
        mesh::Packet* path = createPathReturn(sender, client->secret, packet->path, packet->path_len,
                                              PAYLOAD_TYPE_RESPONSE, reply_data, 12);
        if (path) sendFlood(path, SERVER_RESPONSE_DELAY);
      } else {
        mesh::Packet* reply = createDatagram(PAYLOAD_TYPE_RESPONSE, sender, client->secret, reply_data, 12);
        if (reply) {
          if (client->out_path_len >= 0) {  // we have an out_path, so send DIRECT
            sendDirect(reply, client->out_path, client->out_path_len, SERVER_RESPONSE_DELAY);
          } else {
            sendFlood(reply, SERVER_RESPONSE_DELAY);
          }
        }
      }
    }
  }

  int  matching_peer_indexes[MAX_CLIENTS];

  int searchPeersByHash(const uint8_t* hash) override {
    int n = 0;
    for (int i = 0; i < MAX_CLIENTS; i++) {
      if (known_clients[i].id.isHashMatch(hash)) {
        matching_peer_indexes[n++] = i;  // store the INDEXES of matching contacts (for subsequent 'peer' methods)
      }
    }
    return n;
  }

  void getPeerSharedSecret(uint8_t* dest_secret, int peer_idx) override {
    int i = matching_peer_indexes[peer_idx];
    if (i >= 0 && i < MAX_CLIENTS) {
      // lookup pre-calculated shared_secret
      memcpy(dest_secret, known_clients[i].secret, PUB_KEY_SIZE);
    } else {
      MESH_DEBUG_PRINTLN("getPeerSharedSecret: Invalid peer idx: %d", i);
    }
  }

  void onAdvertRecv(mesh::Packet* packet, const mesh::Identity& id, uint32_t timestamp, const uint8_t* app_data, size_t app_data_len) {
    mesh::Mesh::onAdvertRecv(packet, id, timestamp, app_data, app_data_len);  // chain to super impl

    // if this a zero hop advert, add it to neighbours
    if (packet->path_len == 0) {
      AdvertDataParser parser(app_data, app_data_len);
      if (parser.isValid() && parser.getType() == ADV_TYPE_REPEATER) {   // just keep neigbouring Repeaters
        putNeighbour(id, timestamp, packet->getSNR());
      }
    }
  }

  void onPeerDataRecv(mesh::Packet* packet, uint8_t type, int sender_idx, const uint8_t* secret, uint8_t* data, size_t len) override {
    int i = matching_peer_indexes[sender_idx];
    if (i < 0 || i >= MAX_CLIENTS) {  // get from our known_clients table (sender SHOULD already be known in this context)
      MESH_DEBUG_PRINTLN("onPeerDataRecv: invalid peer idx: %d", i);
      return;
    }
    auto client = &known_clients[i];
    if (type == PAYLOAD_TYPE_REQ) {  // request (from a Known admin client!)
      uint32_t timestamp;
      memcpy(&timestamp, data, 4);

      if (timestamp > client->last_timestamp) {  // prevent replay attacks
        int reply_len = handleRequest(client, timestamp, &data[4], len - 4);
        if (reply_len == 0) return;  // invalid command

        client->last_timestamp = timestamp;
        client->last_activity = getRTCClock()->getCurrentTime();

        if (packet->isRouteFlood()) {
          // let this sender know path TO here, so they can use sendDirect(), and ALSO encode the response
          mesh::Packet* path = createPathReturn(client->id, secret, packet->path, packet->path_len,
                                                PAYLOAD_TYPE_RESPONSE, reply_data, reply_len);
          if (path) sendFlood(path, SERVER_RESPONSE_DELAY);
        } else {
          mesh::Packet* reply = createDatagram(PAYLOAD_TYPE_RESPONSE, client->id, secret, reply_data, reply_len);
          if (reply) {
            if (client->out_path_len >= 0) {  // we have an out_path, so send DIRECT
              sendDirect(reply, client->out_path, client->out_path_len, SERVER_RESPONSE_DELAY);
            } else {
              sendFlood(reply, SERVER_RESPONSE_DELAY);
            }
          }
        }
      } else {
        MESH_DEBUG_PRINTLN("onPeerDataRecv: possible replay attack detected");
      }
    } else if (type == PAYLOAD_TYPE_TXT_MSG && len > 5 && client->is_admin) {   // a CLI command
      uint32_t sender_timestamp;
      memcpy(&sender_timestamp, data, 4);  // timestamp (by sender's RTC clock - which could be wrong)
      uint flags = (data[4] >> 2);   // message attempt number, and other flags

      if (!(flags == TXT_TYPE_PLAIN || flags == TXT_TYPE_CLI_DATA)) {
        MESH_DEBUG_PRINTLN("onPeerDataRecv: unsupported text type received: flags=%02x", (uint32_t)flags);
      } else if (sender_timestamp >= client->last_timestamp) {  // prevent replay attacks
        bool is_retry = (sender_timestamp == client->last_timestamp);
        client->last_timestamp = sender_timestamp;
        client->last_activity = getRTCClock()->getCurrentTime();

        // len can be > original length, but 'text' will be padded with zeroes
        data[len] = 0; // need to make a C string again, with null terminator

        if (flags == TXT_TYPE_PLAIN) {  // for legacy CLI, send Acks
          uint32_t ack_hash;    // calc truncated hash of the message timestamp + text + sender pub_key, to prove to sender that we got it
          mesh::Utils::sha256((uint8_t *) &ack_hash, 4, data, 5 + strlen((char *)&data[5]), client->id.pub_key, PUB_KEY_SIZE);

          mesh::Packet* ack = createAck(ack_hash);
          if (ack) {
            if (client->out_path_len < 0) {
              sendFlood(ack, TXT_ACK_DELAY);
            } else {
              sendDirect(ack, client->out_path, client->out_path_len, TXT_ACK_DELAY);
            }
          }
        }

        uint8_t temp[166];
        char *command = (char *) &data[5];
        char *reply = (char *) &temp[5];
        if (is_retry) {
          *reply = 0;
        } else {
          handleCommand(sender_timestamp, command, reply);
        }
        int text_len = strlen(reply);
        if (text_len > 0) {
          uint32_t timestamp = getRTCClock()->getCurrentTimeUnique();
          if (timestamp == sender_timestamp) {
            // WORKAROUND: the two timestamps need to be different, in the CLI view
            timestamp++;
          }
          memcpy(temp, &timestamp, 4);   // mostly an extra blob to help make packet_hash unique
          temp[4] = (TXT_TYPE_CLI_DATA << 2);   // NOTE: legacy was: TXT_TYPE_PLAIN

          auto reply = createDatagram(PAYLOAD_TYPE_TXT_MSG, client->id, secret, temp, 5 + text_len);
          if (reply) {
            if (client->out_path_len < 0) {
              sendFlood(reply, CLI_REPLY_DELAY_MILLIS);
            } else {
              sendDirect(reply, client->out_path, client->out_path_len, CLI_REPLY_DELAY_MILLIS);
            }
          }
        }
      } else {
        MESH_DEBUG_PRINTLN("onPeerDataRecv: possible replay attack detected");
      }
    }
  }

  bool onPeerPathRecv(mesh::Packet* packet, int sender_idx, const uint8_t* secret, uint8_t* path, uint8_t path_len, uint8_t extra_type, uint8_t* extra, uint8_t extra_len) override {
    // TODO: prevent replay attacks
    int i = matching_peer_indexes[sender_idx];

    if (i >= 0 && i < MAX_CLIENTS) {  // get from our known_clients table (sender SHOULD already be known in this context)
      MESH_DEBUG_PRINTLN("PATH to client, path_len=%d", (uint32_t) path_len);
      auto client = &known_clients[i];
      memcpy(client->out_path, path, client->out_path_len = path_len);  // store a copy of path, for sendDirect()
    } else {
      MESH_DEBUG_PRINTLN("onPeerPathRecv: invalid peer idx: %d", i);
    }

    // NOTE: no reciprocal path send!!
    return false;
  }

public:
  MyMesh(mesh::MainBoard& board, mesh::Radio& radio, mesh::MillisecondClock& ms, mesh::RNG& rng, mesh::RTCClock& rtc, mesh::MeshTables& tables)
     : mesh::Mesh(radio, ms, rng, rtc, *new StaticPoolPacketManager(32), tables),
      _cli(board, rtc, &_prefs, this), telemetry(MAX_PACKET_PAYLOAD - 4)
  {
    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
    memset(neighbours, 0, sizeof(neighbours));
  #endif

    // defaults
    memset(&_prefs, 0, sizeof(_prefs));
    _prefs.airtime_factor = 1.0;    // one half
    _prefs.rx_delay_base =   0.0f;  // turn off by default, was 10.0;
    _prefs.tx_delay_factor = 0.5f;   // was 0.25f
    StrHelper::strncpy(_prefs.node_name, ADVERT_NAME, sizeof(_prefs.node_name));
    _prefs.node_lat = ADVERT_LAT;
    _prefs.node_lon = ADVERT_LON;
    StrHelper::strncpy(_prefs.password, ADMIN_PASSWORD, sizeof(_prefs.password));
    _prefs.freq = LORA_FREQ;
    _prefs.sf = LORA_SF;
    _prefs.bw = LORA_BW;
    _prefs.cr = LORA_CR;
    _prefs.tx_power_dbm = LORA_TX_POWER;
    _prefs.advert_interval = 1;  // default to 2 minutes for NEW installs
    _prefs.flood_advert_interval = 3;   // 3 hours
    _prefs.flood_max = 64;
    _prefs.interference_threshold = 0;  // disabled
  }

  void begin(FILESYSTEM* fs) {
    mesh::Mesh::begin();
    _fs = fs;
    // load persisted prefs
    _cli.loadPrefs(_fs);

    radio_set_params(_prefs.freq, _prefs.bw, _prefs.sf, _prefs.cr);
    radio_set_tx_power(_prefs.tx_power_dbm);

    updateAdvertTimer();
    updateFloodAdvertTimer();
  }

  const char* getFirmwareVer() override { return FIRMWARE_VERSION; }
  const char* getBuildDate() override { return FIRMWARE_BUILD_DATE; }
  const char* getRole() override { return FIRMWARE_ROLE; }
  const char* getNodeName() { return _prefs.node_name; }
  NodePrefs* getNodePrefs() { 
    return &_prefs; 
  }

  void savePrefs() override {
    _cli.savePrefs(_fs);
  }

  void applyTempRadioParams(float freq, float bw, uint8_t sf, uint8_t cr, int timeout_mins) override {
    set_radio_at = futureMillis(2000);   // give CLI reply some time to be sent back, before applying temp radio params
    pending_freq = freq;
    pending_bw = bw;
    pending_sf = sf;
    pending_cr = cr;

    revert_radio_at = futureMillis(2000 + timeout_mins*60*1000);   // schedule when to revert radio params
  }

  bool formatFileSystem() override {
#if defined(NRF52_PLATFORM) || defined(STM32_PLATFORM)
    return InternalFS.format();
#elif defined(RP2040_PLATFORM)
    return LittleFS.format();
#elif defined(ESP32)
    return SPIFFS.format();
#else
    #error "need to implement file system erase"
    return false;
#endif
  }

  void sendSelfAdvertisement(int delay_millis) override {
    mesh::Packet* pkt = createSelfAdvert();
    if (pkt) {
      sendFlood(pkt, delay_millis);
    } else {
      MESH_DEBUG_PRINTLN("ERROR: unable to create advertisement packet!");
    }
  }

  void updateAdvertTimer() override {
    if (_prefs.advert_interval > 0) {  // schedule local advert timer
      next_local_advert = futureMillis( ((uint32_t)_prefs.advert_interval) * 2 * 60 * 1000);
    } else {
      next_local_advert = 0;  // stop the timer
    }
  }
  void updateFloodAdvertTimer() override {
    if (_prefs.flood_advert_interval > 0) {  // schedule flood advert timer
      next_flood_advert = futureMillis( ((uint32_t)_prefs.flood_advert_interval) * 60 * 60 * 1000);
    } else {
      next_flood_advert = 0;  // stop the timer
    }
  }

  void setLoggingOn(bool enable) override { _logging = enable; }

  void eraseLogFile() override {
    _fs->remove(PACKET_LOG_FILE);
  }

  void dumpLogFile() override {
#if defined(RP2040_PLATFORM)
    File f = _fs->open(PACKET_LOG_FILE, "r");
#else
    File f = _fs->open(PACKET_LOG_FILE);
#endif
    if (f) {
      while (f.available()) {
        int c = f.read();
        if (c < 0) break;
        Serial.print((char)c);
      }
      f.close();
    }
  }

  void setTxPower(uint8_t power_dbm) override {
    radio_set_tx_power(power_dbm);
  }

  void formatNeighborsReply(char *reply) override {
    char *dp = reply;

#if MAX_NEIGHBOURS
    for (int i = 0; i < MAX_NEIGHBOURS && dp - reply < 134; i++) {
      NeighbourInfo* neighbour = &neighbours[i];
      if (neighbour->heard_timestamp == 0) continue;    // skip empty slots

      // add new line if not first item
      if (i > 0) *dp++ = '\n';

      char hex[10];
      // get 4 bytes of neighbour id as hex
      mesh::Utils::toHex(hex, neighbour->id.pub_key, 4);

      // add next neighbour
      uint32_t secs_ago = getRTCClock()->getCurrentTime() - neighbour->heard_timestamp;
      sprintf(dp, "%s:%d:%d", hex, secs_ago, neighbour->snr);
      while (*dp) dp++;   // find end of string
    }
#endif
    if (dp == reply) {   // no neighbours, need empty response
      strcpy(dp, "-none-"); dp += 6;
    }
    *dp = 0;  // null terminator
  }

  mesh::LocalIdentity& getSelfId() override { return self_id; }

  void clearStats() override {
    radio_driver.resetStats();
    resetStats();
    ((SimpleMeshTables *)getTables())->resetStats();
  }

  void handleCommand(uint32_t sender_timestamp, char* command, char* reply) {
    while (*command == ' ') command++;   // skip leading spaces

    if (strlen(command) > 4 && command[2] == '|') {  // optional prefix (for companion radio CLI)
      memcpy(reply, command, 3);  // reflect the prefix back
      reply += 3;
      command += 3;
    }

    _cli.handleCommand(sender_timestamp, command, reply);  // common CLI commands
  }

  void loop() {
    mesh::Mesh::loop();

    if (next_flood_advert && millisHasNowPassed(next_flood_advert)) {
      mesh::Packet* pkt = createSelfAdvert();
      if (pkt) sendFlood(pkt);

      updateFloodAdvertTimer();   // schedule next flood advert
      updateAdvertTimer();   // also schedule local advert (so they don't overlap)
    } else if (next_local_advert && millisHasNowPassed(next_local_advert)) {
      mesh::Packet* pkt = createSelfAdvert();
      if (pkt) sendZeroHop(pkt);

      updateAdvertTimer();   // schedule next local advert
    }

    if (set_radio_at && millisHasNowPassed(set_radio_at)) {   // apply pending (temporary) radio params
      set_radio_at = 0;  // clear timer
      radio_set_params(pending_freq, pending_bw, pending_sf, pending_cr);
      MESH_DEBUG_PRINTLN("Temp radio params");
    }

    if (revert_radio_at && millisHasNowPassed(revert_radio_at)) {   // revert radio params to orig
      revert_radio_at = 0;  // clear timer
      radio_set_params(_prefs.freq, _prefs.bw, _prefs.sf, _prefs.cr);
      MESH_DEBUG_PRINTLN("Radio params restored");
    }

  #ifdef DISPLAY_CLASS
    ui_task.loop();
  #endif
  }
};

StdRNG fast_rng;
SimpleMeshTables tables;

MyMesh the_mesh(board, radio_driver, *new ArduinoMillis(), fast_rng, rtc_clock, tables);

void halt() {
  while (1) ;
}

static char command[160];

void setup() {
  Serial.begin(115200);
  delay(1000);

  board.begin();

#ifdef DISPLAY_CLASS
  if (display.begin()) {
    display.startFrame();
    display.print("Please wait...");
    display.endFrame();
  }
#endif

  if (!radio_init()) { halt(); }

  fast_rng.begin(radio_get_rng_seed());

  FILESYSTEM* fs;
#if defined(NRF52_PLATFORM) || defined(STM32_PLATFORM)
  InternalFS.begin();
  fs = &InternalFS;
  IdentityStore store(InternalFS, "");
#elif defined(ESP32)
  SPIFFS.begin(true);
  fs = &SPIFFS;
  IdentityStore store(SPIFFS, "/identity");
#elif defined(RP2040_PLATFORM)
  LittleFS.begin();
  fs = &LittleFS;
  IdentityStore store(LittleFS, "/identity");
  store.begin();
#else
  #error "need to define filesystem"
#endif
  if (!store.load("_main", the_mesh.self_id)) {
    MESH_DEBUG_PRINTLN("Generating new keypair");
    the_mesh.self_id = radio_new_identity();   // create new random identity
    int count = 0;
    while (count < 10 && (the_mesh.self_id.pub_key[0] == 0x00 || the_mesh.self_id.pub_key[0] == 0xFF)) {  // reserved id hashes
      the_mesh.self_id = radio_new_identity(); count++;
    }
    store.save("_main", the_mesh.self_id);
  }

  Serial.print("Repeater ID: ");
  mesh::Utils::printHex(Serial, the_mesh.self_id.pub_key, PUB_KEY_SIZE); Serial.println();

  command[0] = 0;

  sensors.begin();

  the_mesh.begin(fs);

#ifdef DISPLAY_CLASS
  ui_task.begin(the_mesh.getNodePrefs(), FIRMWARE_BUILD_DATE, FIRMWARE_VERSION);
#endif

  // send out initial Advertisement to the mesh
  the_mesh.sendSelfAdvertisement(16000);
}

void loop() {
  int len = strlen(command);
  while (Serial.available() && len < sizeof(command)-1) {
    char c = Serial.read();
    if (c != '\n') {
      command[len++] = c;
      command[len] = 0;
    }
    Serial.print(c);
  }
  if (len == sizeof(command)-1) {  // command buffer full
    command[sizeof(command)-1] = '\r';
  }

  if (len > 0 && command[len - 1] == '\r') {  // received complete line
    command[len - 1] = 0;  // replace newline with C string null terminator
    char reply[160];
    the_mesh.handleCommand(0, command, reply);  // NOTE: there is no sender_timestamp via serial!
    if (reply[0]) {
      Serial.print("  -> "); Serial.println(reply);
    }

    command[0] = 0;  // reset command buffer
  }

  the_mesh.loop();
  sensors.loop();
}