101 lines
3.2 KiB
Swift
101 lines
3.2 KiB
Swift
//
|
|
// XORProcessor.swift
|
|
// TunnelKit
|
|
//
|
|
// Created by Davide De Rosa on 11/4/22.
|
|
// Copyright (c) 2024 Davide De Rosa. All rights reserved.
|
|
//
|
|
// https://github.com/passepartoutvpn
|
|
//
|
|
// This file is part of TunnelKit.
|
|
//
|
|
// TunnelKit is free software: you can redistribute it and/or modify
|
|
// it under the terms of the GNU General Public License as published by
|
|
// the Free Software Foundation, either version 3 of the License, or
|
|
// (at your option) any later version.
|
|
//
|
|
// TunnelKit is distributed in the hope that it will be useful,
|
|
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
// GNU General Public License for more details.
|
|
//
|
|
// You should have received a copy of the GNU General Public License
|
|
// along with TunnelKit. If not, see <http://www.gnu.org/licenses/>.
|
|
//
|
|
|
|
import Foundation
|
|
import TunnelKitOpenVPNCore
|
|
|
|
/// Processes data packets according to a XOR method.
|
|
public struct XORProcessor {
|
|
private let method: OpenVPN.XORMethod?
|
|
|
|
public init(method: OpenVPN.XORMethod?) {
|
|
self.method = method
|
|
}
|
|
|
|
/**
|
|
Returns an array of data packets processed according to XOR method.
|
|
|
|
- Parameter packets: The array of packets.
|
|
- Parameter outbound: Set `true` if packets are outbound, `false` otherwise.
|
|
- Returns: The array of packets after XOR processing.
|
|
**/
|
|
public func processPackets(_ packets: [Data], outbound: Bool) -> [Data] {
|
|
guard let _ = method else {
|
|
return packets
|
|
}
|
|
return packets.map {
|
|
processPacket($0, outbound: outbound)
|
|
}
|
|
}
|
|
|
|
/**
|
|
Returns a data packet processed according to XOR method.
|
|
|
|
- Parameter packets: The packet.
|
|
- Parameter outbound: Set `true` if packet is outbound, `false` otherwise.
|
|
- Returns: The packet after XOR processing.
|
|
**/
|
|
public func processPacket(_ packet: Data, outbound: Bool) -> Data {
|
|
guard let method = method else {
|
|
return packet
|
|
}
|
|
switch method {
|
|
case .xormask(let mask):
|
|
return Self.xormask(packet: packet, mask: mask)
|
|
|
|
case .xorptrpos:
|
|
return Self.xorptrpos(packet: packet)
|
|
|
|
case .reverse:
|
|
return Self.reverse(packet: packet)
|
|
|
|
case .obfuscate(let mask):
|
|
if outbound {
|
|
return Self.xormask(packet: Self.xorptrpos(packet: Self.reverse(packet: Self.xorptrpos(packet: packet))), mask: mask)
|
|
} else {
|
|
return Self.xorptrpos(packet: Self.reverse(packet: Self.xorptrpos(packet: Self.xormask(packet: packet, mask: mask))))
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
extension XORProcessor {
|
|
private static func xormask(packet: Data, mask: Data) -> Data {
|
|
Data(packet.enumerated().map { (index, byte) in
|
|
byte ^ [UInt8](mask)[index % mask.count]
|
|
})
|
|
}
|
|
|
|
private static func xorptrpos(packet: Data) -> Data {
|
|
Data(packet.enumerated().map { (index, byte) in
|
|
byte ^ UInt8(truncatingIfNeeded: index &+ 1)
|
|
})
|
|
}
|
|
|
|
private static func reverse(packet: Data) -> Data {
|
|
Data(([UInt8](packet))[0..<1] + ([UInt8](packet)[1...]).reversed())
|
|
}
|
|
}
|