kanonproxy

   

An anonymous proxy written in kotlin.

There are four modules for this project.

Core

The core module is meant to be a library that can run on Android or Linux. It does not provide the client / server functionality. It is able to process packets which have been parsed by https://github.com/compscidr/knet, manage sessions and make outgoing anonymous requests based on the incoming traffic. It also receives the return traffic, and puts them into a queue. Outgoing ICMP requests are made by https://github.com/compscidr/icmp

It is up to consumers of the this library to implement a server or a tun/tap adapter, or a VPN service on Android to make use of this library.

There are example implementations of a client and server in each of the respective modules as well.

Lastly there is a sample Android app which uses a local client and server alongside the Android VPN functionality to intercept the packets.

Usage

The examples below show a contrived example where the packets are manually constructed. This is a valid usecase, however, you probably want instead to parse a stream from an OS via a TUN/TAP driver, or an Android VPN iostream or something. This library takes a list of the Packet type from the knet library https://github.com/compscidr/knet, so if you have a stream, you can convert that stream into a list of packets by parsing it with that lib.

The other thing to note is that in order to handle Icmp traffic, we use the icmp library: https://github.com/compscidr/icmp. Depending on whether you are on linux or android, you should pass the appropriate Icmp object to the proxy. On linux its IcmpLinux on android its IcmpAndroid. You also need to use different dependencies for each. For linux implementation("com.jasonernst.icmp:icmp-linux") and for android implementation("com.jasonernst.icmp:icmp-android")

Linux:

val kanonProxy = KAnonProxy(IcmpLinux)

val payload = "Test Data".toByteArray()
val sourceAddress = InetAddress.getByName("127.0.0.1") as Inet4Address
val sourcePort: UShort = 12345u
val destinationAddress = InetAddress.getByName("127.0.0.1") as Inet4Address
val destinationPort: UShort = 54321u
val udpHeader = UdpHeader(sourcePort, destinationPort, payload.size.toUShort())
val packet =
    Packet(
        Ipv4Header(
            sourceAddress = sourceAddress,
            destinationAddress = destinationAddress,
            protocol = IpType.UDP.value,
            totalLength =
            (
                    Ipv4Header.IP4_MIN_HEADER_LENGTH +
                            udpHeader.totalLength +
                            payload.size.toUShort()
                    ).toUShort(),
        ),
        udpHeader,
        payload,
    )
val packets = listOf(packet)
kAnonProxy.handlePackets(packets)
val response = kanonProxy.takeResponse()

There are more examples of usage in the tests