The SimpleTunnel project contains working examples of the four extension points provided by the Network Extension framework:
- Packet Tunnel Provider
The Packet Tunnel Provider extension point is used to implemnt the client side of a custom network tunneling protocol that encapsulates network data in the form of IP packets. The PacketTunnel target in the SimpleTunnel project produces a sample Packet Tunnel Provider extension.
- App Proxy Provider
The App Proxy Provider extension point is used to implement the client side of a custom network proxy protocol that encapsulates network data in the form of flows of application network data. Both TCP or stream-based and UDP or datagram-based flows of data are supported. The AppProxy target in the SimpleTunnel project produces a sample App Proxy Provider extension.
- Filter Data Provider and Filter Control Provider
The two Filter Provider extension points are used to implement a dynamic, on-device network content filter. The Filter Data Provider extension is responsible for examining network data and making pass/block decisions. The Filter Data Provider extension sandbox prevents the extension from communicating over the network or writing to disk to prevent any leakage of network data. The Filter Control Provider extension can communicate using the network and write to the disk. It is responsible for updating the filtering rules on behalf of the Filter Data Provider extension.
The FilterDataProvider target in the SimpleTunnel project produces a sample Filter Data Provider extension. The FilterControlProvider target in the SimpleTunnel project produces a sample Filter Control Provider extension.e
All of the sample extensions are packaged into the SimpleTunnel app. The SimpleTunnel app contains code demonstrating how to configure and control the various types of Network Extension providers. The SimpleTunnel target in the SimpleTunnel project produces the SimpleTunnel app and all of the sample extensions.
The SimpleTunnel project contains both the client and server sides of a custom network tunneling protocol. The Packet Tunnel Provider and App Proxy Provider extensions implement the client side. The tunnel_server target produces a OS X command-line binary that implements the server side. The server is configured using a plist. A sample plist is included in the tunnel_erver source. To run the server, use this command:
sudo tunnel_server
The NEProvider family of APIs require the following entitlement:
com.apple.developer.networking.networkextension packet-tunnel-provider app-proxy-provider content-filter-provider
The SimpleTunnel.app and the provider extensions will not run if they are not code signed with this entitlement.