Testing playground to support the peernet protocol on android phones. The implementation above is a proof of concept android application. There is currently no modifications done to the peernet core to get it running on android phones. As a brief the entire project is done using Kotlin with Go mobile.

Screenshots:

Disclaimer:

It is important to note that there could be scenarios where the phone could potencially freeze. The current commits are currently unstable.

Current Features:

Upload file to peernet
1. Add files to warehouse
2. Add file to blockchain
Download file from peernet
View latest files uploaded

Build from gomobile:

The following steps below demonstrate how to build the application:

Create go project with the package called mobile

## The following applies for linux 
- mkdir mobile 
- cd mobile/
- go mod init <module name>
- touch mobile.go

add to mobile.go

package mobile

import (
	"fmt"
	"github.com/PeernetOfficial/core"
	"github.com/PeernetOfficial/core/webapi"
	"github.com/google/uuid"
	"net/http"
	"time"
)

// MobileMain The following function is called as a bind function
// from the Kotlin implementation
func MobileMain(path string) {

	var config core.Config

	// Load the config file
	core.LoadConfig(path+"Config.yaml", &config)

	//Setting modified paths in the config file
	config.SearchIndex = path + "data/search_Index/"
	config.BlockchainGlobal = path + "data/blockchain/"
	config.BlockchainMain = path + "data/blockchain_main/"
	config.WarehouseMain = path + "data/warehouse/"
	config.GeoIPDatabase = path + "data/GeoLite2-City.mmdb"
	config.LogFile = path + "data/log.txt"
    
	// save modified config changes
	core.SaveConfig(path+"Config.yaml", &config)

	backendInit, status, err := core.Init("Your application/1.0", path+"Config.yaml", nil)
	if status != core.ExitSuccess {
		fmt.Printf("Error %d initializing config: %s\n", status, err.Error())
		return
	}

	// start config api server
	webapi.Start(backendInit, []string{"127.0.0.1:5125"}, false, "", "", 10*time.Second, 10*time.Second, uuid.Nil)

	backendInit.Connect()

	// Checks if the go code can access the internet
	if !connected() {
		fmt.Print("Not connected to the internet ")
	} else {
		fmt.Print("Connected")
	}

}

func connected() (ok bool) {
	_, err := http.Get("http://clients3.google.com/generate_204")
	if err != nil {
		return false
	}
	return true
}

Install go mobile

go install golang.org/x/mobile/cmd/gomobile@latest

Initialize go mobile

gomobile init

Add path for Android NDK

export ANDROID_HOME=$HOME/Android/Sdk

Generate .aar and .jar file

gomobile bind -target android .

Output:
mobile.aar  mobile-sources.jar

clone the following repo

git clone https://github.com/PeernetOfficial/core-android

add the following files(i.e mobile.aar,mobile-sources.jar) to the following path. Overwrite it if the file already exists

/<path of the repo>/core-android/app/libs/

Open the project in android studio and click the play button.

Implementation

// Todo

Indentified issues

The core-android only supports upto Android API level 29.

Api level 30 issue

The following is a list of the ways that apps are affected by this change (from Api level 30 onwards):

NetworkInterface.getHardwareAddress() returns null for every interface.
Apps cannot use the bind() function on NETLINK_ROUTE sockets.
The ip command does not return information about interfaces.
Apps cannot send RTM_GETLINK messages.

source (https://developer.android.com/training/articles/user-data-ids#mac-11-plus)

Possible solution

" SDK 30 prohibits syscall.NetlinkRIB(syscall.RTM_GETADDR, ...) which Go's net.Interfaces uses. Implement an Android specific version of net.Interfaces to use instead.

Passing primitive types across JNI is relatively straightforward, passing a single object of a complex class is annoying but still possible, but passing lists and other more complex data structures is way harder. As such, this commit added a Java routine to render the interface information to a string and pass that across JNI as a primitive type for Go code to parse. " PR with a solution: https://github.com/tailscale/tailscale-android/pull/21

Track issue