multicast_dns 0.2.0 not detecting mDNS packets

I'm trying to do a lookup of a specific service using mDNS but the client in Flutter returns nothing albeit the host (Android Device) received the correct packet from mDNS server (see Wireshark section).

Steps to Reproduce

Create mDNS server (you can use the following code in Go. So you need to put the Go code in a file called main.go and run go get -u github.com/hashicorp/mdns && go run main.go, please make sure you're running that command in the same folder of your main.go. To make sure that the server is running, you can run curl -X GET 'http://localhost:8081/' and then you should receive an ok (see screenshot)

package main

import (
	"fmt"
	"github.com/hashicorp/mdns"
	"os"
  "net/http"
)

func health(w http.ResponseWriter, r *http.Request) {
  fmt.Fprintf(w, "ok")
}

func main() {

	hostname, err := os.Hostname()

	if err != nil {
		panic(fmt.Sprintf("Error getting current hostname, description: %s", err.Error()))
	}

	info := []string{"mDNS get server"}

	service, err := mdns.NewMDNSService(hostname, "_test._tcp", "", "", 8080, nil, info)

	if err != nil {
		panic(fmt.Sprintf("Error while exporting the service, description: %s", err.Error()))
	}

	server, err := mdns.NewServer(&mdns.Config{Zone: service})

	if err != nil {
		panic(fmt.Sprintf("Error while setting the discover server up, description: %s", err.Error()))
	}

	defer server.Shutdown()
	
	http.HandleFunc("/", health)
	http.ListenAndServe(":8081",nil)
}

To check if mDNS server is working you can run (OSX): dns-sd -B _test._tcp (Linux: sudo apt-get install avahi-deamonavahi-utils && avahi-browse -rt _test._tcp)
Regarding flutter you can use:

import 'package:multicast_dns/multicast_dns.dart';
import 'dart:io' show Platform;

Future<void> main() async {
  const String name = '_test._tcp.local';
  MDnsClient client;
  if (Platform.isAndroid) {
     var factory = (dynamic host, int port,
         {bool reuseAddress, bool reusePort, int ttl}) {
       print("Hostname $host");
       print("Port ${port.toString()}");
       return RawDatagramSocket.bind(host, port, reuseAddress: true, reusePort: false, ttl: ttl);
     };
     client = MDnsClient(rawDatagramSocketFactory: factory);
   } else {
     client = MDnsClient();
  }
  // Start the client with default options.
  await client.start();

  // Get the PTR record for the service.
  await for (final PtrResourceRecord ptr in client
      .lookup<PtrResourceRecord>(ResourceRecordQuery.serverPointer(name))) {
    // Use the domainName from the PTR record to get the SRV record,
    // which will have the port and local hostname.
    // Note that duplicate messages may come through, especially if any
    // other mDNS queries are running elsewhere on the machine.
    await for (final SrvResourceRecord srv in client.lookup<SrvResourceRecord>(
        ResourceRecordQuery.service(ptr.domainName))) {
      // Domain name will be something like "[email protected]._dartobservatory._tcp.local"
      final String bundleId =
          ptr.domainName; //.substring(0, ptr.domainName.indexOf('@'));
      print('Dart observatory instance found at '
          '${srv.target}:${srv.port} for "$bundleId".');
    }
  }
  client.stop();

  print('Done.');
}

Run flutter run -d <android-device>.

Expected results:
Something like Dart observatory instance found at...

Actual results:

I/ViewRootImpl(28364): jank_removeInvalidNode all the node in jank list is out of time
W/InputMethodManager(28364): startInputReason = 1
I/flutter (28364): Hostname 0.0.0.0
I/flutter (28364): Port 5353
V/AudioManager(28364): playSoundEffect   effectType: 0
V/AudioManager(28364): querySoundEffectsEnabled...
I/flutter (28364): Hostname InternetAddress('127.0.0.1', IPv4)
I/flutter (28364): Port 5353
I/flutter (28364): Hostname InternetAddress('192.168.2.1', IPv4)
I/flutter (28364): Port 5353
I/flutter (28364): Done.

Logs

flutter doctor -v

[✓] Flutter (Channel stable, 2.0.4, on Linux, locale en_US.UTF-8)
    • Flutter version 2.0.4 at /home/puma/snap/flutter/common/flutter
    • Framework revision b1395592de (4 days ago), 2021-04-01 14:25:01 -0700
    • Engine revision 2dce47073a
    • Dart version 2.12.2

[✓] Android toolchain - develop for Android devices (Android SDK version 29.0.2)
    • Android SDK at /mnt/hd/Android/android-sdk-linux
    • Platform android-30, build-tools 29.0.2
    • Java binary at: /snap/android-studio/current/android-studio/jre/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6222593)
    • All Android licenses accepted.

[✓] Chrome - develop for the web
    • Chrome at google-chrome

[✓] Android Studio
    • Android Studio at /snap/android-studio/current/android-studio/
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • android-studio-dir = /snap/android-studio/current/android-studio/
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6222593)

[✓] Connected device (2 available)
    • ANE LX1 (mobile) • testAndroid • android-arm64  • Android 9 (API 28)
    • Chrome (web)     • chrome           • web-javascript • Google Chrome 89.0.4389.114

• No issues found!

flutter attach --verbose

[ +148 ms] executing: [/home/puma/snap/flutter/common/flutter/] git -c log.showSignature=false log -n 1 --pretty=format:%H
[  +72 ms] Exit code 0 from: git -c log.showSignature=false log -n 1 --pretty=format:%H
[        ] b1395592de68cc8ac4522094ae59956dd21a91db
[   +1 ms] executing: [/home/puma/snap/flutter/common/flutter/] git tag --points-at b1395592de68cc8ac4522094ae59956dd21a91db
[  +24 ms] Exit code 0 from: git tag --points-at b1395592de68cc8ac4522094ae59956dd21a91db
[        ] 2.0.4
[  +79 ms] executing: [/home/puma/snap/flutter/common/flutter/] git rev-parse --abbrev-ref --symbolic @{u}
[   +8 ms] Exit code 0 from: git rev-parse --abbrev-ref --symbolic @{u}
[        ] origin/stable
[        ] executing: [/home/puma/snap/flutter/common/flutter/] git ls-remote --get-url origin
[   +9 ms] Exit code 0 from: git ls-remote --get-url origin
[        ] https://github.com/flutter/flutter.git
[ +114 ms] executing: [/home/puma/snap/flutter/common/flutter/] git rev-parse --abbrev-ref HEAD
[  +10 ms] Exit code 0 from: git rev-parse --abbrev-ref HEAD
[        ] stable
[ +151 ms] Artifact Instance of 'AndroidGenSnapshotArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'AndroidInternalBuildArtifacts' is not required, skipping update.
[   +3 ms] Artifact Instance of 'IOSEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'FlutterWebSdk' is not required, skipping update.
[  +12 ms] Artifact Instance of 'WindowsEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'MacOSEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'LinuxEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'LinuxFuchsiaSDKArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'MacOSFuchsiaSDKArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'FlutterRunnerSDKArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'FlutterRunnerDebugSymbols' is not required, skipping update.
[ +154 ms] Artifact Instance of 'MaterialFonts' is not required, skipping update.
[        ] Artifact Instance of 'GradleWrapper' is not required, skipping update.
[        ] Artifact Instance of 'AndroidGenSnapshotArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'AndroidInternalBuildArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'IOSEngineArtifacts' is not required, skipping update.
[   +1 ms] Artifact Instance of 'FlutterWebSdk' is not required, skipping update.
[        ] Artifact Instance of 'FlutterSdk' is not required, skipping update.
[        ] Artifact Instance of 'WindowsEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'MacOSEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'LinuxEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'LinuxFuchsiaSDKArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'MacOSFuchsiaSDKArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'FlutterRunnerSDKArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'FlutterRunnerDebugSymbols' is not required, skipping update.
[        ] Artifact Instance of 'IosUsbArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'IosUsbArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'IosUsbArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'IosUsbArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'IosUsbArtifacts' is not required, skipping update.
[   +1 ms] Artifact Instance of 'FontSubsetArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'PubDependencies' is not required, skipping update.
[ +123 ms] executing: /mnt/hd/Android/android-sdk-linux/platform-tools/adb devices -l
[  +68 ms] List of devices attached
           testAndroid       device usb:2-1.1 product:ANE-LX1 model:ANE_LX1 device:HWANE transport_id:1
[ +102 ms] /mnt/hd/Android/android-sdk-linux/platform-tools/adb -s testAndroid shell getprop
[ +163 ms] Waiting for a connection from Flutter on ANE LX1...
[ +134 ms] Observatory URL on device: http://127.0.0.1:36421/LB5gpdiwoUU=/
[   +2 ms] executing: /mnt/hd/Android/android-sdk-linux/platform-tools/adb -s testAndroid forward tcp:0 tcp:36421
[  +15 ms] 45003
[   +1 ms] Forwarded host port 45003 to device port 36421 for Observatory
[   +9 ms] Connecting to service protocol: http://127.0.0.1:45003/LB5gpdiwoUU=/
[ +186 ms] Launching a Dart Developer Service (DDS) instance at http://127.0.0.1:0, connecting to VM service at http://127.0.0.1:45003/LB5gpdiwoUU=/.
[ +404 ms] Warning: Failed to start DDS: JSON-RPC error 100: Feature is disabled data: {details: A DDS instance is already connected at http://127.0.0.1:32821/rrJgFvQe3xQ=/., request: {jsonrpc: 2.0, method: _yieldControlToDDS, id: 8, params: {uri:
http://127.0.0.1:37321/2bciKM125Ng=/}}}
[  +55 ms] Successfully connected to service protocol: http://127.0.0.1:45003/LB5gpdiwoUU=/
[   +2 ms] executing: /mnt/hd/Android/android-sdk-linux/platform-tools/adb -s testAndroid shell -x logcat -v time -t 1
[  +84 ms] --------- beginning of main
           04-05 14:15:50.212 I/TrafficMonitor( 1273): gettimer:interval=2000
[ +955 ms] DevFS: Creating new filesystem on the device (null)
[  +18 ms] DevFS: Creating failed. Destroying and trying again
[   +1 ms] DevFS: Deleting filesystem on the device (null)
[  +34 ms] DevFS: Deleted filesystem on the device (null)
[  +15 ms] DevFS: Created new filesystem on the device (file:///data/user/0/com.example.test_mdns_client/code_cache/test_mdns_clientJAQOEZ/test_mdns_client/)
[  +10 ms] Updating assets
[ +299 ms] Syncing files to device ANE LX1...
[   +4 ms] <- reset
[        ] Compiling dart to kernel with 0 updated files
[  +17 ms] /home/puma/snap/flutter/common/flutter/bin/cache/dart-sdk/bin/dart --disable-dart-dev /home/puma/snap/flutter/common/flutter/bin/cache/artifacts/engine/linux-x64/frontend_server.dart.snapshot --sdk-root
/home/puma/snap/flutter/common/flutter/bin/cache/artifacts/engine/common/flutter_patched_sdk/ --incremental --target=flutter --debugger-module-names --experimental-emit-debug-metadata --output-dill /tmp/flutter_tools.FDFYPD/flutter_tool.JBRCDK/app.dill
--packages /home/puma/StudioProjects/test_mdns_client/.dart_tool/package_config.json -Ddart.vm.profile=false -Ddart.vm.product=false --enable-asserts --track-widget-creation --filesystem-scheme org-dartlang-root --initialize-from-dill
build/cache.dill.track.dill
[  +12 ms] <- compile package:test_mdns_client/main.dart

pubspec.yaml

name: test_mdns_client
description: A new Flutter project.

publish_to: 'none' # Remove this line if you wish to publish to pub.dev

version: 1.0.0+1

environment:
  sdk: ">=2.7.0 <3.0.0"

dependencies:
  flutter:
    sdk: flutter
  intl: ^0.15.7
  multicast_dns: any

  cupertino_icons: ^1.0.2

dev_dependencies:
  flutter_test:
    sdk: flutter

flutter:
  uses-material-design: true

Wireshark

Source	        Destination	Protocol	Length	Info
192.168.2.1	224.0.0.251	MDNS		76	Standard query 0x0000 PTR _test._tcp.local, "QM" question
192.168.2.4	192.168.2.1	MDNS		180	Standard query response 0x0000 PTR puma._test._tcp.local SRV 10 1 8080 puma A 127.0.1.1 TXT

Where:

192.168.2.1 is testAndroid device;
192.168.2.4 is the device where mDNS server is running on.

Thanks in advance for your help!!!

@biagiopietro

Hi @biagiopietro
I am not familiar with go but I just installed go and tried your command, i get the following error

tahatesser@Tahas-MBP AndroidStudioProjects % go get github.com/hashicorp/mdns && go run main.go
stat main.go: no such file or directory
tahatesser@Tahas-MBP AndroidStudioProjects % ls
tahatesser@Tahas-MBP AndroidStudioProjects %

version

tahatesser@Tahas-MBP AndroidStudioProjects % go version
go version go1.16.3 darwin/amd64
tahatesser@Tahas-MBP AndroidStudioProjects %

Can you please update the reproducible steps
Thank you

@TahaTesser

Hello @TahaTesser,
You need to put the Go code in a file called main.go and run go run main.go, please make sure you're running that command in the same folder of your main.go. To make sure that the server is running, you can run curl -X GET 'http://localhost:8081/' and then you should receive an ok (see screenshot)

Please let me know how can I help (reproducible steps updated)

@biagiopietro

@biagiopietro
I did the same steps, created a folder and main.go file and copied the Go code and ran the command, I get

tahatesser@Tahas-MBP test_go % ls
main.go
tahatesser@Tahas-MBP test_go % go get -u github.com/hashicorp/mdns && go run main.go
main.go:5:2: no required module provides package github.com/hashicorp/mdns: go.mod file not found in current directory or any parent directory; see 'go help modules'
tahatesser@Tahas-MBP test_go %

Edit:
Tried on a different computer, same error

@TahaTesser

@TahaTesser really weird behavior. 😞 I've tried also on OSX and Ubuntu machines without any issue.
Could you please run go mod init main in the same location of your main.go.
It will generate a go.mod file and inside you should put the following line require github.com/hashicorp/mdns v1.0.3 (after module main).
Once you are done please save the file and run again go run main.go (see screenshot for more details)

I saw that you are using Go version go1.16.3 so I upgraded also to that version and I tried the steps described before and they worked for me

@biagiopietro

Hi @biagiopietro
Thanks for the details, go mod init main did the trick and main.go is running and curl -X GET 'http://localhost:8081/' is returning ok

DNS - main.go preview

logs

Launching lib/main.dart on RMX2001 in debug mode...
✓ Built build/app/outputs/flutter-apk/app-debug.apk.
Connecting to VM Service at ws://127.0.0.1:45587/dDUB8u2-dhU=/ws
I/flutter (15328): Hostname 0.0.0.0
I/flutter (15328): Port 5353
I/flutter (15328): Hostname InternetAddress('127.0.0.1', IPv4)
I/flutter (15328): Port 5353
I/flutter (15328): Hostname InternetAddress('192.168.0.159', IPv4)
I/flutter (15328): Port 5353
D/ColorViewRootUtil(15328): nav gesture mode swipeFromBottom ignore false downY 1242 mScreenHeight 2400 mScreenWidth 1080 mStatusBarHeight 54 globalScale 1.125 nav mode 3 event MotionEvent { action=ACTION_DOWN, actionButton=0, id[0]=0, x[0]=432.0, y[0]=1242.0, toolType[0]=TOOL_TYPE_FINGER, buttonState=0, classification=NONE, metaState=0, flags=0x0, edgeFlags=0x0, pointerCount=1, historySize=0, eventTime=291572, downTime=291572, deviceId=3, source=0x1002, displayId=0 } rotation 0
I/flutter (15328): Done.
I/SurfaceView(15328): 229261539 visibleChanged:true -> SurfaceHolder.Callback.surfaceDestroyed
D/Surface (15328): Surface::disconnect(this=0x70d00e6000,api=1)
D/ViewRootImpl(15328): setSurfaceViewCreated, created:false
D/Surface (15328): Surface::disconnect(this=0x70d00e6000,api=-1)
D/SurfaceView(15328): updateScreenMode w:0 h:0 ViewRoot w:1080 h:2400
D/SurfaceView(15328): try to resquest 90Hz
D/ViewRootImpl(15328): set screen refresh mode 0 due to SurfaceView-229261539
I/Choreographer(15328): Skipped 5 frames!  The application may be doing too much work on its main thread.
I/GED     (15328): ged_boost_gpu_freq, level 100, eOrigin 2, final_idx 27, oppidx_max 27, oppidx_min 0
D/Surface (15328): Surface::disconnect(this=0x70d00e4000,api=1)
V/PhoneWindow(15328): DecorView setVisiblity: visibility = 4, Parent = android.view.ViewRootImpl@89f9b74, this = DecorView@9560761[MainActivity]

dependencies:
  flutter:
    sdk: flutter
  cupertino_icons: ^1.0.2
  multicast_dns: ^0.2.2

flutter doctor -v

taha@taha-Lenovo-ideapad-510S-14IKB:~/AndroidStudioProjects$ fsd
[✓] Flutter (Channel stable, 2.0.4, on Linux, locale en_IN)
    • Flutter version 2.0.4 at /home/taha/Code/flutter_stable
    • Framework revision b1395592de (6 days ago), 2021-04-01 14:25:01 -0700
    • Engine revision 2dce47073a
    • Dart version 2.12.2
[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.3)
    • Android SDK at /home/taha/Code/SDK
    • Platform android-30, build-tools 30.0.3
    • ANDROID_HOME = /home/taha/Code/SDK
    • Java binary at: /home/taha/Code/android-studio/jre/bin/java
    • Java version OpenJDK Runtime Environment (build
      1.8.0_242-release-1644-b3-6222593)
    • All Android licenses accepted.
[✓] Chrome - develop for the web
    • Chrome at google-chrome
[✓] Linux toolchain - develop for Linux desktop
    • clang version 10.0.0-4ubuntu1
    • cmake version 3.16.3
    • ninja version 1.10.0
    • pkg-config version 0.29.1
[!] Android Studio (not installed)
    • Android Studio not found; download from
      https://developer.android.com/studio/index.html
      (or visit https://flutter.dev/docs/get-started/install/linux#android-setup
      for detailed instructions).
[✓] Connected device (3 available)
    • RMX2001 (mobile) • EUYTFEUSQSRGDA6D • android-arm64  • Android 10 (API 29)
    • Linux (desktop)  • linux            • linux-x64      • Linux
    • Chrome (web)     • chrome           • web-javascript • Google Chrome
      89.0.4389.90
! Doctor found issues in 1 category.
taha@taha-Lenovo-ideapad-510S-14IKB:~/AndroidStudioProjects$

Thanks for filing the issue

This is still not working properly as of today. A mDNS resolver on my device shows me what I am looking for, but multicast_dns usually does not resolve anything. Sometimes it does....

Hello everyone,
My apologies for the long absence on this.
I will try to follow up again, from what I checked looks like that there are some edge cases on network level that are not handled properly.
I need to dust off again wireshark and have a deep look.

@MarcelKr

Hi @MarcelKr ,@mbalmer, @exaby73
It took a while to investigate a possible solution, I put findings and 2 proposals in the following PR (I just applied one)

[multicast_dns] Optimized Socket Binding: Always bind to 0.0.0.0 for simplicity and efficiency - #79772 packages#6700

Please I'm not an expert and I would like to have also your eyes on it.

(Having a confirmation that it fixes also in your case is really appreciated)

@biagiopietro

Hey @biagiopietro. Thanks for taking the time in attempting to fix this, that's really cool! However I'm absolutely not confident in making any judgement on the PR since I'm neither an expert in dart (which would probably not be the big issue here) nor in the details one needs to know about networking to add profound statements unfortunately :/

[multicast_dns] Optimized Socket Binding: Always bind to 0.0.0.0 for …

b4d79b5 [multicast_dns] Optimized Socket Binding: Always bind to 0.0.…

Roll Packages from 711b4ac to 03f5f6d (21 revisions) (#150779)

This thread has been automatically locked since there has not been any recent activity after it was closed. If you are still experiencing a similar issue, please open a new bug, including the output of flutter doctor -v and a minimal reproduction of the issue.

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multicast_dns 0.2.0 not detecting mDNS packets #79772

Steps to Reproduce

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multicast_dns 0.2.0 not detecting mDNS packets #79772

Description

Steps to Reproduce

Wireshark

Activity

TahaTesser commented on Apr 6, 2021

biagiopietro commented on Apr 6, 2021

TahaTesser commented on Apr 7, 2021

biagiopietro commented on Apr 7, 2021

biagiopietro commented on Apr 7, 2021

TahaTesser commented on Apr 8, 2021

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mbalmer commented on Feb 25, 2024

biagiopietro commented on May 2, 2024

biagiopietro commented on May 9, 2024

MarcelKr commented on May 13, 2024

github-actions commented on Jul 8, 2024

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