Implementing on-device ping

The firmware UI had a feature to send an advert, which is useful,
but often when out and about I'd like to ping a repeater and get
a signal report, especially when scouting areas. I implemented this
by making the last packet RSSI accessible, adding ping functionality
to MyMesh and implementing some UI changes to allow selecting rows
in the recent adverts screen with a long press, then short presses
to move between rows, and a long press to send a ping. I also made the
selection mode time out after 10 seconds.

examples/companion_radio/MyMesh.cpp

@@ -399,6 +399,30 @@ int MyMesh::getRecentlyHeard(AdvertPath dest[], int max_num) {
   return max_num;
 }
 
+int MyMesh::startPing(const ContactInfo& recipient, uint32_t& est_timeout) {
+    if (recipient.out_path_len == OUT_PATH_UNKNOWN) return MSG_SEND_FAILED; // direct path required
+    uint32_t tag = 0;
+    int result = sendRequest(recipient, REQ_TYPE_GET_STATUS, tag, est_timeout);
+    if (result == MSG_SEND_FAILED) return MSG_SEND_FAILED;
+    clearPendingReqs();
+    memcpy(&pending_ping, recipient.id.pub_key, sizeof(pending_ping));
+    pending_ping_at_ms = millis();
+    _ping_result.ready = false;
+    return result;
+}
+
+bool MyMesh::consumePingResult(uint8_t* pub_key_prefix, float& snr, int8_t& rssi, float& out_snr, int16_t& out_rssi, uint16_t& rtt_ms) {
+    if (!_ping_result.ready) return false;
+    memcpy(pub_key_prefix, _ping_result.pubkey_prefix, sizeof(_ping_result.pubkey_prefix));
+    snr = _ping_result.snr;
+    rssi = _ping_result.rssi;
+    out_snr = _ping_result.out_snr;
+    out_rssi = _ping_result.out_rssi;
+    rtt_ms = _ping_result.rtt_ms;
+    _ping_result.ready = false;
+    return true;
+}
+
 void MyMesh::onContactPathUpdated(const ContactInfo &contact) {
   out_frame[0] = PUSH_CODE_PATH_UPDATED;
   memcpy(&out_frame[1], contact.id.pub_key, PUB_KEY_SIZE);
@@ -698,6 +722,22 @@ void MyMesh::onContactResponse(const ContactInfo &contact, const uint8_t *data,
       i += 6; // pub_key_prefix
     }
     _serial->writeFrame(out_frame, i);
+  } else if (pending_ping && memcmp(&pending_ping, contact.id.pub_key, sizeof(pending_ping)) == 0) {
+    pending_ping = 0;
+    _ping_result.snr = _last_resp_snr;
+    _ping_result.rssi = _last_resp_rssi;
+    _ping_result.out_snr = 0;
+    _ping_result.out_rssi = 0;
+    if (len >= 48) {  // tag(4) + RepeaterStats up through last_snr at offset 42
+      int16_t their_rssi, their_snr_x4;
+      memcpy(&their_rssi, &data[10], sizeof(their_rssi));
+      memcpy(&their_snr_x4, &data[46], sizeof(their_snr_x4));
+      _ping_result.out_snr = their_snr_x4 / 4.0f;
+      _ping_result.out_rssi = their_rssi;
+    }
+    _ping_result.rtt_ms = (uint16_t)(millis() - pending_ping_at_ms);
+    memcpy(_ping_result.pubkey_prefix, contact.id.pub_key, sizeof(_ping_result.pubkey_prefix));
+    _ping_result.ready = true;
   } else if (len > 4 && // check for status response
              pending_status &&
              memcmp(&pending_status, contact.id.pub_key, 4) == 0 // legacy matching scheme

examples/companion_radio/MyMesh.h

@@ -101,6 +101,8 @@ public:
   void enterCLIRescue();
 
   int  getRecentlyHeard(AdvertPath dest[], int max_num);
+  int  startPing(const ContactInfo& recipient, uint32_t& est_timeout);
+  bool consumePingResult(uint8_t* pub_key_prefix, float& snr, int8_t& rssi, float& out_snr, int16_t& out_rssi, uint16_t& rtt_ms);
 
 protected:
   float getAirtimeBudgetFactor() const override;
@@ -160,7 +162,7 @@ protected:
   bool getChannelForSave(uint8_t channel_idx, ChannelDetails& ch) override { return getChannel(channel_idx, ch); }
 
   void clearPendingReqs() {
-    pending_login = pending_status = pending_telemetry = pending_discovery = pending_req = 0;
+    pending_login = pending_status = pending_telemetry = pending_discovery = pending_req = pending_ping = 0;
   }
 
 public:
@@ -206,6 +208,19 @@ private:
   uint32_t pending_status;
   uint32_t pending_telemetry, pending_discovery;   // pending _TELEMETRY_REQ
   uint32_t pending_req;   // pending _BINARY_REQ
+
+  uint32_t pending_ping;
+  unsigned long pending_ping_at_ms;
+  struct {
+	  uint8_t pubkey_prefix[6];
+	  bool ready;
+	  float snr;
+	  int8_t rssi;
+	  float out_snr;
+	  int16_t out_rssi;
+	  uint16_t rtt_ms;
+  } _ping_result;
+
   BaseSerialInterface *_serial;
   AbstractUITask* _ui;
 

examples/companion_radio/ui-new/UITask.cpp

@@ -107,7 +107,11 @@ class HomeScreen : public UIScreen {
   uint8_t _page;
   bool _shutdown_init;
   AdvertPath recent[UI_RECENT_LIST_SIZE];
-
+  bool _select_mode = false;
+  int  _select_idx = 0;
+  unsigned long _select_at_ms = 0;
+  bool _ping_in_flight = false;
+  unsigned long _ping_deadline = 0;
 
   void renderBatteryIndicator(DisplayDriver& display, uint16_t batteryMilliVolts) {
     // Convert millivolts to percentage
@@ -185,6 +189,26 @@ public:
     if (_shutdown_init && !_task->isButtonPressed()) {  // must wait for USR button to be released
       _task->shutdown();
     }
+    if (_select_mode && millis() - _select_at_ms > 10000) {
+      _select_mode = false;
+    }
+    if (_ping_in_flight) {
+      uint8_t pubkey[6];
+      float snr, out_snr;
+      int8_t rssi;
+      int16_t out_rssi;
+      uint16_t rtt_ms;
+      if (the_mesh.consumePingResult(pubkey, snr, rssi, out_snr, out_rssi, rtt_ms)) {
+        char buf[80];
+        sprintf(buf, "rx SNR %.1f RSSI %d\ntx SNR %.1f RSSI %d  %dms",
+                snr, rssi, out_snr, out_rssi, rtt_ms);
+        _task->showAlert(buf, 5000);
+        _ping_in_flight = false;
+      } else if (millis() > _ping_deadline) {
+        _task->showAlert("no response", 3000);
+        _ping_in_flight = false;
+      }
+    }
   }
 
   int render(DisplayDriver& display) override {
@@ -241,6 +265,12 @@ public:
       for (int i = 0; i < UI_RECENT_LIST_SIZE; i++, y += 11) {
         auto a = &recent[i];
         if (a->name[0] == 0) continue;  // empty slot
+        display.setColor(DisplayDriver::GREEN);
+        if (_select_mode && i == _select_idx) {
+          display.setColor(DisplayDriver::YELLOW);
+          display.drawRect(0, y - 1, display.width(), 11);
+          display.setColor(DisplayDriver::GREEN);  // restore for text
+        }
         int secs = _rtc->getCurrentTime() - a->recv_timestamp;
         if (secs < 60) {
           sprintf(tmp, "%ds", secs);
@@ -414,6 +444,35 @@ public:
   }
 
   bool handleInput(char c) override {
+    if (_page == HomePage::RECENT && _select_mode) {
+        if (c == KEY_NEXT || c == KEY_RIGHT) {
+            for (int i = 1; i <= UI_RECENT_LIST_SIZE; i++) {
+                int idx = (_select_idx + i) % UI_RECENT_LIST_SIZE;
+                if (recent[idx].name[0] != 0) { _select_idx = idx; break; }
+            }
+            _select_at_ms = millis();
+            return true;
+        }
+        if (c == KEY_ENTER) {
+            auto* contact = the_mesh.lookupContactByPubKey(recent[_select_idx].pubkey_prefix, 6);
+            if (contact == NULL) {
+                _task->showAlert("not in contacts", 2000);
+            } else {
+                uint32_t est_timeout = 0;
+                int result = the_mesh.startPing(*contact, est_timeout);
+                if (result == MSG_SEND_FAILED) {
+                    _task->showAlert("no direct path", 2000);
+                } else {
+                    _task->showAlert("Pinging...", 800);
+                    _ping_in_flight = true;
+                    _ping_deadline = millis() + 7000;
+                }
+            }
+            _select_mode = false;
+            return true;
+        }
+        return false;
+    }
     if (c == KEY_LEFT || c == KEY_PREV) {
       _page = (_page + HomePage::Count - 1) % HomePage::Count;
       return true;
@@ -433,6 +492,16 @@ public:
       }
       return true;
     }
+    if (c == KEY_ENTER && _page == HomePage::RECENT) {
+        for (int i = 0; i < UI_RECENT_LIST_SIZE; i++) {
+            if (recent[i].name[0] != 0) {
+                _select_idx = i;
+                _select_mode = true;
+                _select_at_ms = millis();
+                return true;
+            }
+        }
+    }
     if (c == KEY_ENTER && _page == HomePage::ADVERT) {
       _task->notify(UIEventType::ack);
       if (the_mesh.advert()) {
@@ -592,8 +661,21 @@ void UITask::begin(DisplayDriver* display, SensorManager* sensors, NodePrefs* no
 }
 
 void UITask::showAlert(const char* text, int duration_millis) {
-  strcpy(_alert, text);
+  strncpy(_alert, text, sizeof(_alert) - 1);
+  _alert[sizeof(_alert) - 1] = '\0';
+  _alert_line_count = 1;
+  for (char* p = _alert; *p; p++) {
+    if (*p == '\n') {
+      *p = '\0';
+      _alert_line_count++;
+    }
+  }
   _alert_expiry = millis() + duration_millis;
+  if (_display != NULL && !_display->isOn() && !hasConnection()) {
+    _display->turnOn();
+  }
+  _auto_off = millis() + AUTO_OFF_MILLIS;
+  _next_refresh = 100;
 }
 
 void UITask::notify(UIEventType t) {
@@ -797,11 +879,19 @@ void UITask::loop() {
         _display->setTextSize(1);
         int y = _display->height() / 3;
         int p = _display->height() / 32;
+        const int line_h = 12;
+        int box_h = y;
+        int needed = p*6 + line_h * _alert_line_count;
+        if (needed > box_h) box_h = needed;
         _display->setColor(DisplayDriver::DARK);
-        _display->fillRect(p, y, _display->width() - p*2, y);
+        _display->fillRect(p, y, _display->width() - p*2, box_h);
         _display->setColor(DisplayDriver::LIGHT);  // draw box border
-        _display->drawRect(p, y, _display->width() - p*2, y);
+        _display->drawRect(p, y, _display->width() - p*2, box_h);
-        _display->drawTextCentered(_display->width() / 2, y + p*3, _alert);
+        const char* line = _alert;
+        for (uint8_t i = 0; i < _alert_line_count; i++) {
+          _display->drawTextCentered(_display->width() / 2, y + p*3 + i*line_h, line);
+          line += strlen(line) + 1;  // step past the '\0' separator
+        }
         _next_refresh = _alert_expiry;   // will need refresh when alert is dismissed
       } else {
         _next_refresh = millis() + delay_millis;

examples/companion_radio/ui-new/UITask.h

@@ -35,6 +35,7 @@ class UITask : public AbstractUITask {
   NodePrefs* _node_prefs;
   char _alert[80];
   unsigned long _alert_expiry;
+  uint8_t _alert_line_count;
   int _msgcount;
   unsigned long ui_started_at, next_batt_chck;
   int next_backlight_btn_check = 0;

src/Dispatcher.cpp

@@ -203,6 +203,7 @@ void Dispatcher::checkRecv() {
       } else {
         if (tryParsePacket(pkt, raw, len)) {
           pkt->_snr = _radio->getLastSNR() * 4.0f;
+          pkt->_rssi = _radio->getLastRSSI();
           score = _radio->packetScore(_radio->getLastSNR(), len);
           air_time = _radio->getEstAirtimeFor(len);
           rx_air_time += air_time;
@@ -359,6 +360,7 @@ Packet* Dispatcher::obtainNewPacket() {
   } else {
     pkt->payload_len = pkt->path_len = 0;
     pkt->_snr = 0;
+    pkt->_rssi = 0;
   }
   return pkt;
 }

src/Packet.h

@@ -49,6 +49,7 @@ public:
   uint8_t path[MAX_PATH_SIZE];
   uint8_t payload[MAX_PACKET_PAYLOAD];
   int8_t _snr;
+  int8_t _rssi;
 
   /**
    * \brief calculate the hash of payload + type
@@ -90,6 +91,7 @@ public:
   bool isMarkedDoNotRetransmit() const { return header == 0xFF; }
 
   float getSNR() const { return ((float)_snr) / 4.0f; }
+  int8_t getRSSI() const { return _rssi; }
 
   /**
    * \returns  the encoded/wire format length of this packet

src/helpers/BaseChatMesh.cpp

@@ -281,6 +281,8 @@ void BaseChatMesh::onPeerDataRecv(mesh::Packet* packet, uint8_t type, int sender
       }
     }
   } else if (type == PAYLOAD_TYPE_RESPONSE && len > 0) {
+    _last_resp_snr = packet->getSNR();
+    _last_resp_rssi = packet->getRSSI();
     onContactResponse(from, data, len);
     if (packet->isRouteFlood() && from.out_path_len != OUT_PATH_UNKNOWN) {
       // we have direct path, but other node is still sending flood response, so maybe they didn't receive reciprocal path properly(?)
@@ -298,6 +300,8 @@ bool BaseChatMesh::onPeerPathRecv(mesh::Packet* packet, int sender_idx, const ui
 
   ContactInfo& from = contacts[i];
 
+  _last_resp_snr = packet->getSNR();
+  _last_resp_rssi = packet->getRSSI();
   return onContactPathRecv(from, packet->path, packet->path_len, path, path_len, extra_type, extra, extra_len);
 }
 

src/helpers/BaseChatMesh.h

@@ -75,6 +75,9 @@ class BaseChatMesh : public mesh::Mesh {
   void sendAckTo(const ContactInfo& dest, uint32_t ack_hash);
 
 protected:
+  float _last_resp_snr = 0;
+  int8_t _last_resp_rssi = 0;
+
   BaseChatMesh(mesh::Radio& radio, mesh::MillisecondClock& ms, mesh::RNG& rng, mesh::RTCClock& rtc, mesh::PacketManager& mgr, mesh::MeshTables& tables)
       : mesh::Mesh(radio, ms, rng, rtc, mgr, tables)
   {