3.5 KiB
Android + ZeroTier SDK
Welcome!
Imagine a flat, encrypted, no-configuration LAN for all of the instances of your Android app.
This short tutorial will show you how to enable ZeroTier functionality for your Android app with little to no code modification. Check out our ZeroTier SDK page for more info on how the integration works and Shim Techniques for a discussion of shims available for your app/technology.
In this example we aim to set up a minimal Android Studio project which contains all of the components necessary to enable ZeroTier for your app. If you'd rather skip all of these steps and grab the code, look in the sdk/android folder in the source tree. Otherwise, let's get started!
Step 1: Build Shared Library libZeroTierOneJNI.so
Open zerotiersdk/integrations/Android/proj and build it.
Note: Building the project will take a while if you are building for all architectures, See note below on how to speed up this process.
The resultant zerotiersdk/integrations/Android/java/libs/YOUR_ARCH/libZeroTierOneJNI.so will be what you want to import for your own project to provide the shim interface to your app. Select your architecture and copy the shared library into YourProject/src/main/jniLibs/YOUR_ARCH/
Step 2: App Code Modifications
Create new package called Netcon in your project and add a new file called NetconWrapper.java containing:
package Netcon;
public class NetconWrapper {
public native void startOneService();
static { System.loadLibrary("ZeroTierOneJNI”); } // Loads JNI code
}
And now, start the service:
new Thread(new Runnable() {
public void run() {
NetconWrapper wrapper = new NetconWrapper();
wrapper.startOneService(); // Calls to JNI code
}
}).start();
Step 3: Pick a shim for your app
If functional interposition isn't available for the API or library you've chosen to use, ZeroTier offers a SOCKS5 proxy server which can allow connectivity to your virtual network as long as your client API supports the SOCKS5 protocol. This proxy service will run alongside the tap service and can be turned on by compiling with the -DUSE_SOCKS_PROXY flag. By default, the proxy service is available at 0.0.0.0:1337.
Step 4: Add necessary app permissions
In order for your application to write the auth keys to the internal storage you'll need to set a few permissions in your AndroidManifest.xml file:
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
Step 5: Join a network!
Simply call zt_join_network("XXXXXXXXXXXXXXXX")
Additional notes
As mentioned above, you can reduce the amount of time required to build the ZeroTier JNI library by only building for the architectures you want. You can specify the architectures in zerotiersdk/integrations/Android/java/jni/Application.mk
If you change the method/class/package name for the Netcon glue code in NetconWrapper.java (Not recommended!), you must also change the name of the JNI implementation in the Netcon source to match the new java name. For example, if the glue code is contained in a package Java.com.example.joseph.NetconProxyTest, a JNI implementation name of Java_com_example_joseph_netconproxytest_NetconWrapper_startOneService would be required in the appropriate C/C++ source/header files.