Updated NETunnelProvider save format

Signed-off-by: Eric Kuck <eric@bluelinelabs.com>

13 files changed, 494 insertions, 169 deletions

diff --git a/WireGuard/Shared/Model/Configuration.swift b/WireGuard/Shared/Model/Configuration.swift
deleted file mode 100644
index 77dfe97..0000000
--- a/WireGuard/Shared/Model/Configuration.swift
+++ /dev/null
@@ -1,68 +0,0 @@
-// SPDX-License-Identifier: MIT
-// Copyright © 2018 WireGuard LLC. All Rights Reserved.
-
-import Foundation
-
-@available(OSX 10.14, iOS 12.0, *)
-final class TunnelConfiguration: Codable {
-    var interface: InterfaceConfiguration
-    let peers: [PeerConfiguration]
-
-    static let keyLength: Int = 32
-
-    init(interface: InterfaceConfiguration, peers: [PeerConfiguration]) {
-        self.interface = interface
-        self.peers = peers
-
-        let peerPublicKeysArray = peers.map { $0.publicKey }
-        let peerPublicKeysSet = Set<Data>(peerPublicKeysArray)
-        if peerPublicKeysArray.count != peerPublicKeysSet.count {
-            fatalError("Two or more peers cannot have the same public key")
-        }
-    }
-}
-
-@available(OSX 10.14, iOS 12.0, *)
-struct InterfaceConfiguration: Codable {
-    var name: String
-    var privateKey: Data
-    var addresses = [IPAddressRange]()
-    var listenPort: UInt16?
-    var mtu: UInt16?
-    var dns = [DNSServer]()
-
-    init(name: String, privateKey: Data) {
-        self.name = name
-        self.privateKey = privateKey
-        if name.isEmpty {
-            fatalError("Empty name")
-        }
-        if privateKey.count != TunnelConfiguration.keyLength {
-            fatalError("Invalid private key")
-        }
-    }
-}
-
-@available(OSX 10.14, iOS 12.0, *)
-struct PeerConfiguration: Codable {
-    var publicKey: Data
-    var preSharedKey: Data? {
-        didSet(value) {
-            if let value = value {
-                if value.count != TunnelConfiguration.keyLength {
-                    fatalError("Invalid preshared key")
-                }
-            }
-        }
-    }
-    var allowedIPs = [IPAddressRange]()
-    var endpoint: Endpoint?
-    var persistentKeepAlive: UInt16?
-
-    init(publicKey: Data) {
-        self.publicKey = publicKey
-        if publicKey.count != TunnelConfiguration.keyLength {
-            fatalError("Invalid public key")
-        }
-    }
-}
diff --git a/WireGuard/Shared/Model/DNSServer.swift b/WireGuard/Shared/Model/DNSServer.swift
index d1c75fc..8703fbb 100644
--- a/WireGuard/Shared/Model/DNSServer.swift
+++ b/WireGuard/Shared/Model/DNSServer.swift
@@ -4,52 +4,50 @@
 import Foundation
 import Network
 
-@available(OSX 10.14, iOS 12.0, *)
 struct DNSServer {
     let address: IPAddress
-}
-
-// MARK: Converting to and from String
-
-extension DNSServer {
-    init?(from addressString: String) {
-        if let addr = IPv4Address(addressString) {
-            address = addr
-        } else if let addr = IPv6Address(addressString) {
-            address = addr
-        } else {
-            return nil
-        }
-    }
-    func stringRepresentation() -> String {
-        return "\(address)"
+    
+    init(address: IPAddress) {
+        self.address = address
     }
 }
 
-// MARK: Codable
-
-@available(OSX 10.14, iOS 12.0, *)
 extension DNSServer: Codable {
     public func encode(to encoder: Encoder) throws {
         var container = encoder.singleValueContainer()
-        try container.encode(address.rawValue)
+        try container.encode(stringRepresentation)
     }
+    
     public init(from decoder: Decoder) throws {
-        let container = try decoder.singleValueContainer()
-        var data = try container.decode(Data.self)
-        let ipAddressFromData: IPAddress? = {
-            switch data.count {
-            case 4: return IPv4Address(data)
-            case 16: return IPv6Address(data)
-            default: return nil
-            }
-        }()
-        guard let ipAddress = ipAddressFromData else {
+        let values = try decoder.singleValueContainer()
+        let addressString = try values.decode(String.self)
+        
+        if let address = IPv4Address(addressString) {
+            self.address = address
+        } else if let address = IPv6Address(addressString) {
+            self.address = address
+        } else {
             throw DecodingError.invalidData
         }
-        address = ipAddress
     }
+
     enum DecodingError: Error {
         case invalidData
     }
 }
+
+extension DNSServer {
+    var stringRepresentation: String {
+        return "\(address)"
+    }
+    
+    init?(from addressString: String) {
+        if let addr = IPv4Address(addressString) {
+            address = addr
+        } else if let addr = IPv6Address(addressString) {
+            address = addr
+        } else {
+            return nil
+        }
+    }
+}
diff --git a/WireGuard/Shared/Model/Endpoint.swift b/WireGuard/Shared/Model/Endpoint.swift
index 3a4beee..891c564 100644
--- a/WireGuard/Shared/Model/Endpoint.swift
+++ b/WireGuard/Shared/Model/Endpoint.swift
@@ -4,15 +4,48 @@
 import Foundation
 import Network
 
-@available(OSX 10.14, iOS 12.0, *)
 struct Endpoint {
     let host: NWEndpoint.Host
     let port: NWEndpoint.Port
+    
+    init(host: NWEndpoint.Host, port: NWEndpoint.Port) {
+        self.host = host
+        self.port = port
+    }
 }
 
-// MARK: Converting to and from String
+extension Endpoint: Codable {
+    init(from decoder: Decoder) throws {
+        let container = try decoder.singleValueContainer()
+        let endpointString = try container.decode(String.self)
+        guard let endpoint = Endpoint(from: endpointString) else {
+            throw DecodingError.invalidData
+        }
+        self = endpoint
+    }
+    
+    func encode(to encoder: Encoder) throws {
+        var container = encoder.singleValueContainer()
+        try container.encode(stringRepresentation)
+    }
+    
+    enum DecodingError: Error {
+        case invalidData
+    }
+}
 
 extension Endpoint {
+    var stringRepresentation: String {
+        switch host {
+        case .name(let hostname, _):
+            return "\(hostname):\(port)"
+        case .ipv4(let address):
+            return "\(address):\(port)"
+        case .ipv6(let address):
+            return "[\(address)]:\(port)"
+        }
+    }
+    
     init?(from string: String) {
         // Separation of host and port is based on 'parse_endpoint' function in
         // https://git.zx2c4.com/WireGuard/tree/src/tools/config.c
@@ -41,37 +74,6 @@ extension Endpoint {
         host = NWEndpoint.Host(hostString)
         port = endpointPort
     }
-    func stringRepresentation() -> String {
-        switch host {
-        case .name(let hostname, _):
-            return "\(hostname):\(port)"
-        case .ipv4(let address):
-            return "\(address):\(port)"
-        case .ipv6(let address):
-            return "[\(address)]:\(port)"
-        }
-    }
-}
-
-// MARK: Codable
-
-@available(OSX 10.14, iOS 12.0, *)
-extension Endpoint: Codable {
-    public func encode(to encoder: Encoder) throws {
-        var container = encoder.singleValueContainer()
-        try container.encode(stringRepresentation())
-    }
-    public init(from decoder: Decoder) throws {
-        let container = try decoder.singleValueContainer()
-        let endpointString = try container.decode(String.self)
-        guard let endpoint = Endpoint(from: endpointString) else {
-            throw DecodingError.invalidData
-        }
-        self = endpoint
-    }
-    enum DecodingError: Error {
-        case invalidData
-    }
 }
 
 extension Endpoint {
diff --git a/WireGuard/Shared/Model/IPAddressRange.swift b/WireGuard/Shared/Model/IPAddressRange.swift
index 0098c32..da4cbd5 100644
--- a/WireGuard/Shared/Model/IPAddressRange.swift
+++ b/WireGuard/Shared/Model/IPAddressRange.swift
@@ -4,16 +4,28 @@
 import Foundation
 import Network
 
-@available(OSX 10.14, iOS 12.0, *)
 struct IPAddressRange {
     let address: IPAddress
     var networkPrefixLength: UInt8
+    
+    init(address: IPAddress, networkPrefixLength: UInt8) {
+        self.address = address
+        self.networkPrefixLength = networkPrefixLength
+    }
 }
 
-// MARK: Converting to and from String
-
 extension IPAddressRange {
+    var stringRepresentation: String {
+        return "\(address)/\(networkPrefixLength)"
+    }
+    
     init?(from string: String) {
+        guard let parsed = IPAddressRange.parseAddressString(string) else { return nil }
+        address = parsed.0
+        networkPrefixLength = parsed.1
+    }
+    
+    private static func parseAddressString(_ string: String) -> (IPAddress, UInt8)? {
         let endOfIPAddress = string.lastIndex(of: "/") ?? string.endIndex
         let addressString = String(string[string.startIndex ..< endOfIPAddress])
         let address: IPAddress
@@ -24,7 +36,8 @@ extension IPAddressRange {
         } else {
             return nil
         }
-        let maxNetworkPrefixLength: UInt8 = (address is IPv4Address) ? 32 : 128
+        
+        let maxNetworkPrefixLength: UInt8 = address is IPv4Address ? 32 : 128
         var networkPrefixLength: UInt8
         if endOfIPAddress < string.endIndex { // "/" was located
             let indexOfNetworkPrefixLength = string.index(after: endOfIPAddress)
@@ -35,47 +48,25 @@ extension IPAddressRange {
         } else {
             networkPrefixLength = maxNetworkPrefixLength
         }
-        self.address = address
-        self.networkPrefixLength = networkPrefixLength
-    }
-    func stringRepresentation() -> String {
-        return "\(address)/\(networkPrefixLength)"
+        
+        return (address, networkPrefixLength)
     }
 }
 
-// MARK: Codable
-
-@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)
+        try container.encode(stringRepresentation)
     }
+    
     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
+        let values = try decoder.singleValueContainer()
+        let addressString = try values.decode(String.self)
+        guard let parsed = IPAddressRange.parseAddressString(addressString) else { throw DecodingError.invalidData }
+        address = parsed.0
+        networkPrefixLength = parsed.1
     }
+    
     enum DecodingError: Error {
         case invalidData
     }
diff --git a/WireGuard/Shared/Model/InterfaceConfiguration.swift b/WireGuard/Shared/Model/InterfaceConfiguration.swift
new file mode 100644
index 0000000..dfcb1fc
--- /dev/null
+++ b/WireGuard/Shared/Model/InterfaceConfiguration.swift
@@ -0,0 +1,59 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2018 WireGuard LLC. All Rights Reserved.
+
+import Foundation
+
+struct InterfaceConfiguration {
+    var name: String
+    var privateKey: Data
+    var addresses = [IPAddressRange]()
+    var listenPort: UInt16?
+    var mtu: UInt16?
+    var dns = [DNSServer]()
+    
+    init(name: String, privateKey: Data) {
+        self.name = name
+        self.privateKey = privateKey
+        if name.isEmpty {
+            fatalError("Empty name")
+        }
+        if privateKey.count != TunnelConfiguration.keyLength {
+            fatalError("Invalid private key")
+        }
+    }
+}
+
+extension InterfaceConfiguration: Codable {
+    enum CodingKeys: String, CodingKey {
+        case name = "Name"
+        case privateKey = "PrivateKey"
+        case addresses = "Address"
+        case listenPort = "ListenPort"
+        case mtu = "MTU"
+        case dns = "DNS"
+    }
+    
+    init(from decoder: Decoder) throws {
+        let values = try decoder.container(keyedBy: CodingKeys.self)
+        name = try values.decode(String.self, forKey: .name)
+        privateKey = try Data(base64Encoded: values.decode(String.self, forKey: .privateKey))!
+        addresses = try values.decode([IPAddressRange].self, forKey: .addresses)
+        listenPort = try? values.decode(UInt16.self, forKey: .listenPort)
+        mtu = try? values.decode(UInt16.self, forKey: .mtu)
+        dns = try values.decode([DNSServer].self, forKey: .dns)
+    }
+    
+    func encode(to encoder: Encoder) throws {
+        var container = encoder.container(keyedBy: CodingKeys.self)
+        try container.encode(name, forKey: .name)
+        try container.encode(privateKey.base64EncodedString(), forKey: .privateKey)
+        try container.encode(addresses, forKey: .addresses)
+        if let listenPort = listenPort {
+            try container.encode(listenPort, forKey: .listenPort)
+        }
+        if let mtu = mtu {
+            try container.encode(mtu, forKey: .mtu)
+        }
+        try container.encode(dns, forKey: .dns)
+    }
+}
diff --git a/WireGuard/Shared/Model/Legacy/LegacyDNSServer.swift b/WireGuard/Shared/Model/Legacy/LegacyDNSServer.swift
new file mode 100644
index 0000000..f2afcd7
--- /dev/null
+++ b/WireGuard/Shared/Model/Legacy/LegacyDNSServer.swift
@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2018 WireGuard LLC. All Rights Reserved.
+
+import Foundation
+import Network
+
+struct LegacyDNSServer: Codable {
+    let address: IPAddress
+    
+    init(from decoder: Decoder) throws {
+        let container = try decoder.singleValueContainer()
+        var data = try container.decode(Data.self)
+        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
+    }
+    
+    func encode(to encoder: Encoder) throws {
+        var container = encoder.singleValueContainer()
+        try container.encode(address.rawValue)
+    }
+
+    enum DecodingError: Error {
+        case invalidData
+    }
+}
+
+extension LegacyDNSServer {
+    var migrated: DNSServer {
+        return DNSServer(address: address)
+    }
+}
+
+extension Array where Element == LegacyDNSServer {
+    var migrated: [DNSServer] {
+        return map { $0.migrated }
+    }
+}
diff --git a/WireGuard/Shared/Model/Legacy/LegacyEndpoint.swift b/WireGuard/Shared/Model/Legacy/LegacyEndpoint.swift
new file mode 100644
index 0000000..7a80be4
--- /dev/null
+++ b/WireGuard/Shared/Model/Legacy/LegacyEndpoint.swift
@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2018 WireGuard LLC. All Rights Reserved.
+
+import Foundation
+import Network
+
+struct LegacyEndpoint: Codable {
+    let host: NWEndpoint.Host
+    let port: NWEndpoint.Port
+    
+    public init(from decoder: Decoder) throws {
+        let container = try decoder.singleValueContainer()
+        let endpointString = try container.decode(String.self)
+        guard !endpointString.isEmpty else { throw DecodingError.invalidData }
+        let startOfPort: String.Index
+        let hostString: String
+        if endpointString.first! == "[" {
+            // Look for IPv6-style endpoint, like [::1]:80
+            let startOfHost = endpointString.index(after: endpointString.startIndex)
+            guard let endOfHost = endpointString.dropFirst().firstIndex(of: "]") else { throw DecodingError.invalidData }
+            let afterEndOfHost = endpointString.index(after: endOfHost)
+            guard endpointString[afterEndOfHost] == ":" else { throw DecodingError.invalidData }
+            startOfPort = endpointString.index(after: afterEndOfHost)
+            hostString = String(endpointString[startOfHost ..< endOfHost])
+        } else {
+            // Look for an IPv4-style endpoint, like 127.0.0.1:80
+            guard let endOfHost = endpointString.firstIndex(of: ":") else { throw DecodingError.invalidData }
+            startOfPort = endpointString.index(after: endOfHost)
+            hostString = String(endpointString[endpointString.startIndex ..< endOfHost])
+        }
+        guard let endpointPort = NWEndpoint.Port(String(endpointString[startOfPort ..< endpointString.endIndex])) else { throw DecodingError.invalidData }
+        let invalidCharacterIndex = hostString.unicodeScalars.firstIndex { char in
+            return !CharacterSet.urlHostAllowed.contains(char)
+        }
+        guard invalidCharacterIndex == nil else { throw DecodingError.invalidData }
+        host = NWEndpoint.Host(hostString)
+        port = endpointPort
+    }
+    
+    public func encode(to encoder: Encoder) throws {
+        let stringRepresentation: String
+        switch host {
+        case .name(let hostname, _):
+            stringRepresentation = "\(hostname):\(port)"
+        case .ipv4(let address):
+            stringRepresentation = "\(address):\(port)"
+        case .ipv6(let address):
+            stringRepresentation = "[\(address)]:\(port)"
+        }
+        
+        var container = encoder.singleValueContainer()
+        try container.encode(stringRepresentation)
+    }
+
+    enum DecodingError: Error {
+        case invalidData
+    }
+}
+
+extension LegacyEndpoint {
+    var migrated: Endpoint {
+        return Endpoint(host: host, port: port)
+    }
+}
diff --git a/WireGuard/Shared/Model/Legacy/LegacyIPAddressRange.swift b/WireGuard/Shared/Model/Legacy/LegacyIPAddressRange.swift
new file mode 100644
index 0000000..ade87f2
--- /dev/null
+++ b/WireGuard/Shared/Model/Legacy/LegacyIPAddressRange.swift
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2018 WireGuard LLC. All Rights Reserved.
+
+import Foundation
+import Network
+
+struct LegacyIPAddressRange: Codable {
+    let address: IPAddress
+    let networkPrefixLength: UInt8
+    
+    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
+    }
+    
+    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)
+    }
+
+    enum DecodingError: Error {
+        case invalidData
+    }
+}
+
+extension LegacyIPAddressRange {
+    var migrated: IPAddressRange {
+        return IPAddressRange(address: address, networkPrefixLength: networkPrefixLength)
+    }
+}
+
+extension Array where Element == LegacyIPAddressRange {
+    var migrated: [IPAddressRange] {
+        return map { $0.migrated }
+    }
+}
diff --git a/WireGuard/Shared/Model/Legacy/LegacyInterfaceConfiguration.swift b/WireGuard/Shared/Model/Legacy/LegacyInterfaceConfiguration.swift
new file mode 100644
index 0000000..680c8d7
--- /dev/null
+++ b/WireGuard/Shared/Model/Legacy/LegacyInterfaceConfiguration.swift
@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2018 WireGuard LLC. All Rights Reserved.
+
+import Foundation
+
+struct LegacyInterfaceConfiguration: Codable {
+    let name: String
+    let privateKey: Data
+    let addresses: [LegacyIPAddressRange]
+    let listenPort: UInt16?
+    let mtu: UInt16?
+    let dns: [LegacyDNSServer]
+}
+
+extension LegacyInterfaceConfiguration {
+    var migrated: InterfaceConfiguration {
+        var interface = InterfaceConfiguration(name: name, privateKey: privateKey)
+        interface.addresses = addresses.migrated
+        interface.listenPort = listenPort
+        interface.mtu = mtu
+        interface.dns = dns.migrated
+        return interface
+    }
+}
diff --git a/WireGuard/Shared/Model/Legacy/LegacyPeerConfiguration.swift b/WireGuard/Shared/Model/Legacy/LegacyPeerConfiguration.swift
new file mode 100644
index 0000000..5a61b4a
--- /dev/null
+++ b/WireGuard/Shared/Model/Legacy/LegacyPeerConfiguration.swift
@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2018 WireGuard LLC. All Rights Reserved.
+
+import Foundation
+
+struct LegacyPeerConfiguration: Codable {
+    let publicKey: Data
+    let preSharedKey: Data?
+    let allowedIPs: [LegacyIPAddressRange]
+    let endpoint: LegacyEndpoint?
+    let persistentKeepAlive: UInt16?
+}
+
+extension LegacyPeerConfiguration {
+    var migrated: PeerConfiguration {
+        var configuration = PeerConfiguration(publicKey: publicKey)
+        configuration.preSharedKey = preSharedKey
+        configuration.allowedIPs = allowedIPs.migrated
+        configuration.endpoint = endpoint?.migrated
+        configuration.persistentKeepAlive = persistentKeepAlive
+        return configuration
+    }
+}
+
+extension Array where Element == LegacyPeerConfiguration {
+    var migrated: [PeerConfiguration] {
+        return map { $0.migrated }
+    }
+}
diff --git a/WireGuard/Shared/Model/Legacy/LegacyTunnelConfiguration.swift b/WireGuard/Shared/Model/Legacy/LegacyTunnelConfiguration.swift
new file mode 100644
index 0000000..ac369b9
--- /dev/null
+++ b/WireGuard/Shared/Model/Legacy/LegacyTunnelConfiguration.swift
@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2018 WireGuard LLC. All Rights Reserved.
+
+import Foundation
+
+final class LegacyTunnelConfiguration: Codable {
+    let interface: LegacyInterfaceConfiguration
+    let peers: [LegacyPeerConfiguration]
+}
+
+extension LegacyTunnelConfiguration {
+    var migrated: TunnelConfiguration {
+        return TunnelConfiguration(interface: interface.migrated, peers: peers.migrated)
+    }
+}
diff --git a/WireGuard/Shared/Model/PeerConfiguration.swift b/WireGuard/Shared/Model/PeerConfiguration.swift
new file mode 100644
index 0000000..0fad842
--- /dev/null
+++ b/WireGuard/Shared/Model/PeerConfiguration.swift
@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2018 WireGuard LLC. All Rights Reserved.
+
+import Foundation
+
+struct PeerConfiguration {
+    var publicKey: Data
+    var preSharedKey: Data? {
+        didSet(value) {
+            if let value = value {
+                if value.count != TunnelConfiguration.keyLength {
+                    fatalError("Invalid preshared key")
+                }
+            }
+        }
+    }
+    var allowedIPs = [IPAddressRange]()
+    var endpoint: Endpoint?
+    var persistentKeepAlive: UInt16?
+    
+    init(publicKey: Data) {
+        self.publicKey = publicKey
+        if publicKey.count != TunnelConfiguration.keyLength {
+            fatalError("Invalid public key")
+        }
+    }
+}
+
+extension PeerConfiguration: Codable {
+    enum CodingKeys: String, CodingKey {
+        case publicKey = "PublicKey"
+        case preSharedKey = "PreSharedKey"
+        case allowedIPs = "AllowedIPs"
+        case endpoint = "Endpoint"
+        case persistentKeepAlive = "PersistentKeepAlive"
+    }
+    
+    init(from decoder: Decoder) throws {
+        let values = try decoder.container(keyedBy: CodingKeys.self)
+        publicKey = try Data(base64Encoded: values.decode(String.self, forKey: .publicKey))!
+        if let base64PreSharedKey = try? values.decode(Data.self, forKey: .preSharedKey) {
+            preSharedKey = Data(base64Encoded: base64PreSharedKey)
+        } else {
+            preSharedKey = nil
+        }
+        allowedIPs = try values.decode([IPAddressRange].self, forKey: .allowedIPs)
+        endpoint = try? values.decode(Endpoint.self, forKey: .endpoint)
+        persistentKeepAlive = try? values.decode(UInt16.self, forKey: .persistentKeepAlive)
+    }
+    
+    func encode(to encoder: Encoder) throws {
+        var container = encoder.container(keyedBy: CodingKeys.self)
+        try container.encode(publicKey.base64EncodedString(), forKey: .publicKey)
+        if let preSharedKey = preSharedKey {
+            try container.encode(preSharedKey.base64EncodedString(), forKey: .preSharedKey)
+        }
+        
+        try container.encode(allowedIPs, forKey: .allowedIPs)
+        if let endpoint = endpoint {
+            try container.encode(endpoint, forKey: .endpoint)
+        }
+        if let persistentKeepAlive = persistentKeepAlive {
+            try container.encode(persistentKeepAlive, forKey: .persistentKeepAlive)
+        }
+    }
+}
diff --git a/WireGuard/Shared/Model/TunnelConfiguration.swift b/WireGuard/Shared/Model/TunnelConfiguration.swift
new file mode 100644
index 0000000..87812cd
--- /dev/null
+++ b/WireGuard/Shared/Model/TunnelConfiguration.swift
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2018 WireGuard LLC. All Rights Reserved.
+
+import Foundation
+
+final class TunnelConfiguration {
+    var interface: InterfaceConfiguration
+    let peers: [PeerConfiguration]
+
+    static let keyLength = 32
+
+    init(interface: InterfaceConfiguration, peers: [PeerConfiguration]) {
+        self.interface = interface
+        self.peers = peers
+
+        let peerPublicKeysArray = peers.map { $0.publicKey }
+        let peerPublicKeysSet = Set<Data>(peerPublicKeysArray)
+        if peerPublicKeysArray.count != peerPublicKeysSet.count {
+            fatalError("Two or more peers cannot have the same public key")
+        }
+    }
+}
+
+extension TunnelConfiguration: Codable {
+    enum CodingKeys: String, CodingKey {
+        case interface = "Interface"
+        case peers = "Peer"
+    }
+    
+    convenience init(from decoder: Decoder) throws {
+        let values = try decoder.container(keyedBy: CodingKeys.self)
+        let interface = try values.decode(InterfaceConfiguration.self, forKey: .interface)
+        let peers = try values.decode([PeerConfiguration].self, forKey: .peers)
+        self.init(interface: interface, peers: peers)
+    }
+    
+    func encode(to encoder: Encoder) throws {
+        var container = encoder.container(keyedBy: CodingKeys.self)
+        try container.encode(interface, forKey: .interface)
+        try container.encode(peers, forKey: .peers)
+    }
+}