Model for an IP Address range

Signed-off-by: Roopesh Chander <roop@roopc.net>

WireGuard/WireGuard.xcodeproj/project.pbxproj

@@ -11,6 +11,7 @@
 		6F7774E2217181B1006A79B3 /* AppDelegate.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6F7774E0217181B1006A79B3 /* AppDelegate.swift */; };
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 		6F7774E82172020C006A79B3 /* Configuration.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6F7774E72172020C006A79B3 /* Configuration.swift */; };
+		6F7774EA217229DB006A79B3 /* IPAddressRange.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6F7774E9217229DB006A79B3 /* IPAddressRange.swift */; };
 		6FF4AC1F211EC472002C96EB /* Assets.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = 6FF4AC1E211EC472002C96EB /* Assets.xcassets */; };
 		6FF4AC22211EC472002C96EB /* LaunchScreen.storyboard in Resources */ = {isa = PBXBuildFile; fileRef = 6FF4AC20211EC472002C96EB /* LaunchScreen.storyboard */; };
 		6FF4AC472120B9E0002C96EB /* NetworkExtension.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 6FF4AC462120B9E0002C96EB /* NetworkExtension.framework */; };
@@ -21,6 +22,7 @@
 		6F7774E0217181B1006A79B3 /* AppDelegate.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = AppDelegate.swift; sourceTree = "<group>"; };
 		6F7774E321718281006A79B3 /* TunnelsListTableViewController.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = TunnelsListTableViewController.swift; sourceTree = "<group>"; };
 		6F7774E72172020C006A79B3 /* Configuration.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Configuration.swift; sourceTree = "<group>"; };
+		6F7774E9217229DB006A79B3 /* IPAddressRange.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = IPAddressRange.swift; sourceTree = "<group>"; };
 		6FF4AC14211EC46F002C96EB /* WireGuard.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = WireGuard.app; sourceTree = BUILT_PRODUCTS_DIR; };
 		6FF4AC1E211EC472002C96EB /* Assets.xcassets */ = {isa = PBXFileReference; lastKnownFileType = folder.assetcatalog; path = Assets.xcassets; sourceTree = "<group>"; };
 		6FF4AC21211EC472002C96EB /* Base */ = {isa = PBXFileReference; lastKnownFileType = file.storyboard; name = Base; path = Base.lproj/LaunchScreen.storyboard; sourceTree = "<group>"; };
@@ -64,6 +66,7 @@
 			isa = PBXGroup;
 			children = (
 				6F7774E72172020C006A79B3 /* Configuration.swift */,
+				6F7774E9217229DB006A79B3 /* IPAddressRange.swift */,
 			);
 			path = Model;
 			sourceTree = "<group>";
@@ -184,6 +187,7 @@
 			files = (
 				6F7774E421718281006A79B3 /* TunnelsListTableViewController.swift in Sources */,
 				6F7774E2217181B1006A79B3 /* AppDelegate.swift in Sources */,
+				6F7774EA217229DB006A79B3 /* IPAddressRange.swift in Sources */,
 				6F7774E82172020C006A79B3 /* Configuration.swift in Sources */,
 				6F7774E1217181B1006A79B3 /* MainViewController.swift in Sources */,
 			);

WireGuard/WireGuard/Model/IPAddressRange.swift

@@ -0,0 +1,54 @@
+//
+//  IPAddressRange.swift
+//  WireGuard
+//
+//  Created by Roopesh Chander on 13/10/18.
+//  Copyright © 2018 WireGuard LLC. All rights reserved.
+//
+
+import Foundation
+import Network
+
+@available(OSX 10.14, iOS 12.0, *)
+struct IPAddressRange {
+    let address: IPAddress
+    var networkPrefixLength: UInt8
+}
+
+@available(OSX 10.14, iOS 12.0, *)
+extension IPAddressRange: Codable {
+    public func encode(to encoder: Encoder) throws {
+        var container = encoder.singleValueContainer()
+        let addressDataLength: Int
+        if address is IPv4Address {
+            addressDataLength = 4
+        } else if address is IPv6Address {
+            addressDataLength = 16
+        } else {
+            fatalError()
+        }
+        var data = Data(capacity: addressDataLength + 1)
+        data.append(address.rawValue)
+        data.append(networkPrefixLength)
+        try container.encode(data)
+    }
+    public init(from decoder: Decoder) throws {
+        let container = try decoder.singleValueContainer()
+        var data = try container.decode(Data.self)
+        networkPrefixLength = data.removeLast()
+        let ipAddressFromData: IPAddress? = {
+            switch (data.count) {
+            case 4: return IPv4Address(data)
+            case 16: return IPv6Address(data)
+            default: return nil
+            }
+        }()
+        guard let ipAddress = ipAddressFromData else {
+            throw DecodingError.invalidData
+        }
+        address = ipAddress
+    }
+    enum DecodingError: Error {
+        case invalidData
+    }
+}