Adds MACAddress type.

Sources/Containerization/ContainerManager.swift

@@ -1,5 +1,5 @@
 //===----------------------------------------------------------------------===//
-// Copyright © 2025 Apple Inc. and the Containerization project authors.
+// Copyright © 2025-2026 Apple Inc. and the Containerization project authors.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -93,7 +93,7 @@ public struct ContainerManager: Sendable {
         public struct Interface: Containerization.Interface, VZInterface, Sendable {
             public let ipv4Address: CIDRv4
             public let ipv4Gateway: IPv4Address?
-            public let macAddress: String?
+            public let macAddress: MACAddress?
 
             // `reference` isn't used concurrently.
             nonisolated(unsafe) private let reference: vmnet_network_ref
@@ -102,7 +102,7 @@ public struct ContainerManager: Sendable {
                 reference: vmnet_network_ref,
                 ipv4Address: CIDRv4,
                 ipv4Gateway: IPv4Address,
-                macAddress: String? = nil
+                macAddress: MACAddress? = nil
             ) {
                 self.ipv4Address = ipv4Address
                 self.ipv4Gateway = ipv4Gateway
@@ -114,7 +114,7 @@ public struct ContainerManager: Sendable {
             public func device() throws -> VZVirtioNetworkDeviceConfiguration {
                 let config = VZVirtioNetworkDeviceConfiguration()
                 if let macAddress = self.macAddress {
-                    guard let mac = VZMACAddress(string: macAddress) else {
+                    guard let mac = VZMACAddress(string: macAddress.description) else {
                         throw ContainerizationError(.invalidArgument, message: "invalid mac address \(macAddress)")
                     }
                     config.macAddress = mac

Sources/Containerization/Interface.swift

@@ -1,5 +1,5 @@
 //===----------------------------------------------------------------------===//
-// Copyright © 2025 Apple Inc. and the Containerization project authors.
+// Copyright © 2025-2026 Apple Inc. and the Containerization project authors.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -26,5 +26,5 @@ public protocol Interface: Sendable {
     var ipv4Gateway: IPv4Address? { get }
 
     /// The interface MAC address, or nil to auto-configure the address.
-    var macAddress: String? { get }
+    var macAddress: MACAddress? { get }
 }

Sources/Containerization/NATInterface.swift

@@ -1,5 +1,5 @@
 //===----------------------------------------------------------------------===//
-// Copyright © 2025 Apple Inc. and the Containerization project authors.
+// Copyright © 2025-2026 Apple Inc. and the Containerization project authors.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -19,9 +19,9 @@ import ContainerizationExtras
 public struct NATInterface: Interface {
     public var ipv4Address: CIDRv4
     public var ipv4Gateway: IPv4Address?
-    public var macAddress: String?
+    public var macAddress: MACAddress?
 
-    public init(ipv4Address: CIDRv4, ipv4Gateway: IPv4Address?, macAddress: String? = nil) {
+    public init(ipv4Address: CIDRv4, ipv4Gateway: IPv4Address?, macAddress: MACAddress? = nil) {
         self.ipv4Address = ipv4Address
         self.ipv4Gateway = ipv4Gateway
         self.macAddress = macAddress

Sources/Containerization/NATNetworkInterface.swift

@@ -1,5 +1,5 @@
 //===----------------------------------------------------------------------===//
-// Copyright © 2025 Apple Inc. and the Containerization project authors.
+// Copyright © 2025-2026 Apple Inc. and the Containerization project authors.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -29,7 +29,7 @@ import Synchronization
 public final class NATNetworkInterface: Interface, Sendable {
     public let ipv4Address: CIDRv4
     public let ipv4Gateway: IPv4Address?
-    public let macAddress: String?
+    public let macAddress: MACAddress?
 
     @available(macOS 26, *)
     // `reference` isn't used concurrently.
@@ -40,7 +40,7 @@ public final class NATNetworkInterface: Interface, Sendable {
         ipv4Address: CIDRv4,
         ipv4Gateway: IPv4Address?,
         reference: sending vmnet_network_ref,
-        macAddress: String? = nil
+        macAddress: MACAddress? = nil
     ) {
         self.ipv4Address = ipv4Address
         self.ipv4Gateway = ipv4Gateway
@@ -52,7 +52,7 @@ public final class NATNetworkInterface: Interface, Sendable {
     public init(
         ipv4Address: CIDRv4,
         ipv4Gateway: IPv4Address?,
-        macAddress: String? = nil
+        macAddress: MACAddress? = nil
     ) {
         self.ipv4Address = ipv4Address
         self.ipv4Gateway = ipv4Gateway
@@ -66,7 +66,7 @@ extension NATNetworkInterface: VZInterface {
     public func device() throws -> VZVirtioNetworkDeviceConfiguration {
         let config = VZVirtioNetworkDeviceConfiguration()
         if let macAddress = self.macAddress {
-            guard let mac = VZMACAddress(string: macAddress) else {
+            guard let mac = VZMACAddress(string: macAddress.description) else {
                 throw ContainerizationError(.invalidArgument, message: "invalid mac address \(macAddress)")
             }
             config.macAddress = mac

Sources/Containerization/VZVirtualMachineInstance.swift

@@ -1,5 +1,5 @@
 //===----------------------------------------------------------------------===//
-// Copyright © 2025 Apple Inc. and the Containerization project authors.
+// Copyright © 2025-2026 Apple Inc. and the Containerization project authors.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -465,7 +465,7 @@ extension NATInterface: VZInterface {
     public func device() throws -> VZVirtioNetworkDeviceConfiguration {
         let config = VZVirtioNetworkDeviceConfiguration()
         if let macAddress = self.macAddress {
-            guard let mac = VZMACAddress(string: macAddress) else {
+            guard let mac = VZMACAddress(string: macAddress.description) else {
                 throw ContainerizationError(.invalidArgument, message: "invalid mac address \(macAddress)")
             }
             config.macAddress = mac

Sources/ContainerizationExtras/CIDR.swift

@@ -1,5 +1,5 @@
 //===----------------------------------------------------------------------===//
-// Copyright © 2025 Apple Inc. and the Containerization project authors.
+// Copyright © 2025-2026 Apple Inc. and the Containerization project authors.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -133,3 +133,16 @@ extension CIDR {
         case invalidAddressRange(lower: String, upper: String)
     }
 }
+
+extension CIDR: Codable {
+    public init(from decoder: Decoder) throws {
+        let container = try decoder.singleValueContainer()
+        let string = try container.decode(String.self)
+        try self.init(string)
+    }
+
+    public func encode(to encoder: Encoder) throws {
+        var container = encoder.singleValueContainer()
+        try container.encode(description)
+    }
+}

Sources/ContainerizationExtras/IPAddress.swift

@@ -1,5 +1,5 @@
 //===----------------------------------------------------------------------===//
-// Copyright © 2025 Apple Inc. and the Containerization project authors.
+// Copyright © 2025-2026 Apple Inc. and the Containerization project authors.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -133,3 +133,16 @@ public enum IPAddress: Sendable, Hashable, CustomStringConvertible, Equatable {
         }
     }
 }
+
+extension IPAddress: Codable {
+    public init(from decoder: Decoder) throws {
+        let container = try decoder.singleValueContainer()
+        let string = try container.decode(String.self)
+        try self.init(string)
+    }
+
+    public func encode(to encoder: Encoder) throws {
+        var container = encoder.singleValueContainer()
+        try container.encode(description)
+    }
+}