Add cell/signal info to system stats panel

Display LTE signal measurements (RSRP, RSRQ, RSSI, PCI, EARFCN) from
DIAG ML1 Serving Cell Measurement messages in the web UI.

- Add CellInfo struct with RwLock cache in gsmtap_parser
- Add CellSignalInfo to SystemStats API response
- Add Cell Signal row to SystemStatsTable with quality indicator
- Support Orbic, Tplink, Tmobile, Wingtech devices (graceful degradation for others)

daemon/src/stats.rs

@@ -9,10 +9,53 @@ use axum::Json;
 use axum::extract::State;
 use axum::http::StatusCode;
 use log::error;
+use rayhunter::gsmtap_parser::get_cached_cell_info;
 use rayhunter::{Device, util::RuntimeMetadata};
 use serde::Serialize;
 use tokio::process::Command;
 
+/// LTE cell/signal information from DIAG measurements.
+/// All fields are optional since they may not be available on all devices
+/// or may not have been received yet.
+#[derive(Debug, Serialize)]
+pub struct CellSignalInfo {
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub rsrp_dbm: Option<f32>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub rsrq_db: Option<f32>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub rssi_dbm: Option<f32>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub pci: Option<u16>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub earfcn: Option<u32>,
+}
+
+/// Get cell/signal information for devices that support DIAG.
+/// Returns None for devices without DIAG support or if no measurements available.
+pub fn get_cell_info(device: &Device) -> Option<CellSignalInfo> {
+    match device {
+        // Devices with DIAG support
+        Device::Orbic | Device::Tplink | Device::Tmobile | Device::Wingtech => {
+            let info = get_cached_cell_info();
+            // Only return if we have at least some data
+            if info.rsrp_dbm.is_some() || info.pci.is_some() {
+                Some(CellSignalInfo {
+                    rsrp_dbm: info.rsrp_dbm,
+                    rsrq_db: info.rsrq_db,
+                    rssi_dbm: info.rssi_dbm,
+                    pci: info.pci,
+                    earfcn: info.earfcn,
+                })
+            } else {
+                None
+            }
+        }
+        // Devices without DIAG support
+        Device::Pinephone | Device::Uz801 => None,
+    }
+}
+
 #[derive(Debug, Serialize)]
 pub struct SystemStats {
     pub disk_stats: DiskStats,
@@ -20,6 +63,8 @@ pub struct SystemStats {
     pub runtime_metadata: RuntimeMetadata,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub battery_status: Option<BatteryState>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub cell_info: Option<CellSignalInfo>,
 }
 
 impl SystemStats {
@@ -36,6 +81,7 @@ impl SystemStats {
                     None
                 }
             },
+            cell_info: get_cell_info(device),
         })
     }
 }

daemon/web/src/lib/components/SystemStatsTable.svelte

@@ -33,6 +33,23 @@
         }
         return text;
     });
+
+    // Cell signal quality assessment based on RSRP
+    // Excellent: >= -80 dBm, Good: -80 to -90, Fair: -90 to -100, Poor: < -100
+    let signal_quality = $derived.by(() => {
+        const rsrp = stats.cell_info?.rsrp_dbm;
+        if (rsrp === undefined) return { label: 'Unknown', color: 'text-gray-500' };
+        if (rsrp >= -80) return { label: 'Excellent', color: 'text-green-600' };
+        if (rsrp >= -90) return { label: 'Good', color: 'text-green-600' };
+        if (rsrp >= -100) return { label: 'Fair', color: 'text-yellow-600' };
+        return { label: 'Poor', color: 'text-red-600' };
+    });
+
+    // Format signal value with unit
+    function formatSignal(value: number | undefined, unit: string): string {
+        if (value === undefined) return '—';
+        return `${value.toFixed(1)} ${unit}`;
+    }
 </script>
 
 <div
@@ -116,6 +133,39 @@
                     </svg>
                 </td>
             </tr>
+            {#if stats.cell_info}
+                <tr class="border-b">
+                    <th class={table_cell_classes}> Cell Signal </th>
+                    <td class={table_cell_classes}>
+                        <div class="flex flex-col gap-1 text-sm">
+                            <div class="flex items-center gap-2">
+                                <span class="font-medium {signal_quality.color}">
+                                    {signal_quality.label}
+                                </span>
+                                {#if stats.cell_info.rsrp_dbm !== undefined}
+                                    <span class="text-gray-600">
+                                        (RSRP: {formatSignal(stats.cell_info.rsrp_dbm, 'dBm')})
+                                    </span>
+                                {/if}
+                            </div>
+                            <div class="text-gray-600 text-xs">
+                                {#if stats.cell_info.pci !== undefined}
+                                    <span>PCI: {stats.cell_info.pci}</span>
+                                {/if}
+                                {#if stats.cell_info.earfcn !== undefined}
+                                    <span class="ml-2">EARFCN: {stats.cell_info.earfcn}</span>
+                                {/if}
+                                {#if stats.cell_info.rsrq_db !== undefined}
+                                    <span class="ml-2">RSRQ: {formatSignal(stats.cell_info.rsrq_db, 'dB')}</span>
+                                {/if}
+                                {#if stats.cell_info.rssi_dbm !== undefined}
+                                    <span class="ml-2">RSSI: {formatSignal(stats.cell_info.rssi_dbm, 'dBm')}</span>
+                                {/if}
+                            </div>
+                        </div>
+                    </td>
+                </tr>
+            {/if}
         </tbody>
     </table>
 </div>

daemon/web/src/lib/systemStats.ts

@@ -3,6 +3,7 @@ export interface SystemStats {
     memory_stats: MemoryStats;
     runtime_metadata: RuntimeMetadata;
     battery_status?: BatteryStatus;
+    cell_info?: CellSignalInfo;
 }
 
 export interface RuntimeMetadata {
@@ -30,3 +31,11 @@ export interface BatteryStatus {
     level: number;
     is_plugged_in: boolean;
 }
+
+export interface CellSignalInfo {
+    rsrp_dbm?: number;
+    rsrq_db?: number;
+    rssi_dbm?: number;
+    pci?: number;
+    earfcn?: number;
+}