Package com.codename1.vpn.tunnel

package com.codename1.vpn.tunnel

Writing the tunnel itself, rather than asking the system to run one.

com.codename1.vpn.profile asks the operating system to run an IKEv2 or IPsec client it already implements, which is what most apps want. This package is the other thing: the app receives raw IP packets and decides what happens to them.

Android only

Tunnels.isSupported() answers true on Android and false everywhere else, including iOS. Ask it, and keep a path for the answer being no.

  • Android: CN1VpnService, which ships in the port and which the builder declares in the manifest for an app that referenced this package. It is a VpnService in the app's own process, needing BIND_VPN_SERVICE and the user's consent. The tunnel runs in that process, so the instance passed to Tunnels.start(VpnTunnel, TunnelSetup) is the instance that runs and everything it closed over is still there.
  • iOS: not supported. A packet tunnel there is an NEPacketTunnelProvider in a Network Extension -- a separate process with its own bundle -- and a Java tunnel needs a virtual machine inside it. The translation that would produce one without the application shell, which uses UIKit APIs an extension may not call, has not been written. ios.vpn.tunnel fails the build rather than generating an extension too broken to compile.
  • Simulator and desktop: a loopback transport, so the packet loop can be exercised without a device.
Why the API is shaped for another process anyway

TunnelSetup.data, TunnelConfiguration and the packet pooling in PacketBuffer all assume the tunnel may be constructed somewhere the app's statics are not, under a memory budget far below an app's. That is the shape a Network Extension needs, and it costs an Android tunnel nothing to be written that way. A tunnel that takes its configuration from VpnTunnel.onStart(TunnelConfiguration) rather than reaching for a static the app set is the one that stays portable.

  • Class
    Description
    PacketBuffer
    One IP packet on its way through the tunnel.
    TunnelConfiguration
    What the tunnel was started with.
    Tunnels
    Starts and stops a packet tunnel this application implements.
    TunnelSetup
    What an application asks the platform to set up before its tunnel runs.
    TunnelStopReason
    Why a tunnel stopped.
    TunnelTransport
    How packets reach the tunnel, which is where the two platforms differ.
    VpnTunnel
    The packet loop, written once for both platforms.