mirror of
https://github.com/meshtastic/Meshtastic-Android.git
synced 2026-06-01 22:19:18 +02:00
James Rich
103 lines
2.8 KiB
Markdown
103 lines
2.8 KiB
Markdown
---
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title: Transport
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nav_order: 5
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last_updated: 2026-05-13
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aliases:
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- ble
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- serial
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- tcp
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- radio-transport
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---
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# Transport
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Meshtastic communicates between the app and radio hardware through multiple transport mechanisms.
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## Transport Abstraction
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The transport layer is abstracted through interfaces in `core/network` and `core/ble`, allowing the app to work identically regardless of the underlying connection type.
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```
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App ← RadioController → Transport (BLE | Serial | TCP)
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```
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## Bluetooth Low Energy (BLE)
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**Module:** `core:ble`
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**Platforms:** Android, Desktop (JVM via Kable), iOS (planned)
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The primary transport for mobile devices and also available on desktop:
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- Service discovery for Meshtastic GATT services
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- Characteristic-based read/write for protobuf packets
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- Connection state management and automatic reconnection
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- MTU negotiation for optimal packet sizes
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### Key Classes
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- `core/ble/` — BLE scanning, connection, and GATT operations
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- Platform-specific implementations in `androidMain` and `jvmMain` (Kable)
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## USB Serial
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**Module:** `core:network`
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**Platforms:** Android (OTG), Desktop
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Serial communication over USB:
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- Uses `usb-serial-for-android` library on Android
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- Direct serial port access on Desktop (JVM)
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- Probe table for supported USB vendor/product IDs
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- Automatic detection when USB device is connected
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### Key Classes
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- Serial prober and transport factory in `core/network`
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- Desktop-specific serial in `desktopApp/src/main/kotlin/.../radio/`
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## TCP/IP
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**Module:** `core:network`
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**Platforms:** Android, Desktop, iOS
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Network-based transport for WiFi-enabled radios:
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- TCP socket connection to radio's IP address
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- Default port: 4403
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- Used for development with simulated radios
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- Available when BLE/USB is impractical
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## Transport Factory
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The `RadioTransportFactory` interface abstracts transport creation:
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```kotlin
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interface RadioTransportFactory {
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val supportedDeviceTypes: List<DeviceType>
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fun createTransport(address: String, service: RadioInterfaceService): RadioTransport
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fun isMockTransport(): Boolean
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fun isAddressValid(address: String?): Boolean
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fun toInterfaceAddress(interfaceId: InterfaceId, rest: String): String
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}
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```
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Platform-specific implementations:
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- **Android:** Supports BLE + USB + TCP
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- **Desktop:** Supports BLE (Kable) + USB + TCP
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- **iOS:** Planned BLE + TCP
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## Connection Lifecycle
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1. **Discovery** — Scan for available radios (BLE scan / USB detect / manual TCP)
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2. **Connection** — Establish link to selected radio
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3. **Handshake** — Exchange node info and configuration
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4. **Active** — Normal message exchange
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5. **Disconnection** — Clean teardown or error recovery
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## Adding a New Transport
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1. Implement `RadioTransport` interface
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2. Register in platform-specific `RadioTransportFactory`
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3. Add connection UI in `feature:connections`
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4. Update DI bindings for the platform
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---
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