mikkeli
ff13d63333
GetMethodID raises NoSuchMethodError when a lookup fails, and any further JNI call made while an exception is pending aborts the process. runIperfLive resolved three method IDs back to back without checking, so the first failure made the second call fatal — turning a diagnosable configuration problem into a SIGABRT with a stack that pointed at the JNI entry rather than the cause. resolve_method() clears the pending exception and returns NULL, and the caller now bails out with a log naming which lookups failed and pointing at the keep rules. The R8 problem this exposed is fixed separately; this is about the failure being reportable rather than fatal, whatever the cause. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
iperf3-gui
A Flutter-based Android GUI wrapper for iperf3, the popular network performance measurement tool.
Features
- Client-mode network throughput testing
- Configurable server, port, duration and parallel streams
- Live iperf3 output, streamed line by line while the test runs
- Stop a running test early
- Copy the transcript to the clipboard
- iperf3 3.19 compiled into the app as a native library — no external binary
Architecture
lib/
├── domain/
│ ├── models/ # TestConfiguration, Iperf3Result
├── data/
│ └── services/ # Iperf3Service (MethodChannel → JNI)
├── ui/
│ └── features/
│ └── test_run/ # TestRunScreen, TestRunViewModel
└── main.dart # App entry point
android/app/src/main/
├── kotlin/…/IperfRunner.kt # MethodChannel handler, runs tests off the platform thread
└── cpp/iperf_jni.c # JNI bridge into the iperf3 API
See docs/README.md for the data flow, the native API surface and the design decisions behind them.
Why JNI instead of executing a binary
Android SELinux in Enforcing mode blocks execve() from the untrusted_app
domain, so shipping an iperf3 ELF in assets and running it via Process.start()
fails with "Permission denied". iperf3 is therefore compiled as a shared library
(libiperf3jni.so) and called in-process over JNI.
assets/iperf3/ still holds the pre-compiled binaries from that earlier
approach. They are not declared in pubspec.yaml, so they are not packaged into
the APK, and nothing in the app reads them.
Building
Prerequisites:
- Flutter 3.47+
- Android SDK with platform android-36
- JDK 17
- NDK r28+ and CMake 3.22.1 (for the native build)
flutter pub get
flutter analyze
flutter test
flutter build apk --debug
adb install -r build/app/outputs/flutter-apk/app-debug.apk
Testing against a local server
iperf3 -s -p 5201 # on a machine on the same network
ip -4 addr show # note its address
Enter that address in the app, then press GO.
Dependencies
- Dart:
provider - Native: iperf3 3.19 + cJSON, built by CMake for
armeabi-v7aandarm64-v8a
License
MIT — bundled iperf3 3.19 is BSD-3-Clause licensed.