Alternative of VpnService in iOS (Swift) - ios

Question

We have an android app that has a custom VPN built into it. We have used VpnService class to implement this feature. This is the code in Android used to build a virtual interface.
We create the tunnel first and then create multiple udp sessions in multiple threads.
try {
if (vpnInterface == null) {
Builder builder = new Builder();
builder.setMtu(1024);
builder.addAddress("10.10.10.9", 32);
builder.addRoute("10.10.10.0", 24);
vpnInterface = builder
.setSession(getString(R.string.app_name))
.setConfigureIntent(pendingIntent)
.setBlocking(true)
.establish();
FileDescriptor vpnFileDescriptor = vpnInterface.getFileDescriptor();
writePacket(vpnFileDescriptor);
readPacket(vpnFileDescriptor);
}
} catch (Exception e) {
e.printStackTrace();
}
We want to do the exact same thing is ios as well. I'm a swift newbie and I tried to work with Network extensions and use the NEPacketTunnelNetworkSettings to replicate this feature but I could not make it work. How would I create a layer 3 virtual network interface in iOS? This is what I have so far.
import NetworkExtension
class PacketTunnelProvider: NEPacketTunnelProvider {
override func startTunnel(options: [String : NSObject]?, completionHandler: #escaping (Error?) -> Void) {
let serverAddress = "10.10.10.10"
let clientAddress = "10.10.10.9"
let mtu = 1024 as NSNumber?
let netMask = "255.255.255.255"
let settings = NEPacketTunnelNetworkSettings(tunnelRemoteAddress: serverAddress)
settings.ipv4Settings = NEIPv4Settings(addresses: [clientAddress], subnetMasks: [netMask])
settings.ipv4Settings?.includedRoutes = [NEIPv4Route.default()]
settings.ipv4Settings?.excludedRoutes = []
settings.mtu = mtu
setTunnelNetworkSettings(settings){ error in
if let e = error {
print("ERROR:",e)
NSLog("Settings error %#", e.localizedDescription)
} else {
NSLog("Settings %#", "Settings have been created successfully and tunnel has started")
}
}
}
override func stopTunnel(with reason: NEProviderStopReason, completionHandler: #escaping () -> Void) {
// Add code here to start the process of stopping the tunnel.
completionHandler()
}
override func handleAppMessage(_ messageData: Data, completionHandler: ((Data?) -> Void)?) {
// Add code here to handle the message.
if let handler = completionHandler {
handler(messageData)
}
}
override func sleep(completionHandler: #escaping () -> Void) {
// Add code here to get ready to sleep.
completionHandler()
}
override func wake() {
// Add code here to wake up.
}
}