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/IPAddressError.swift → Sources/ContainerizationExtras/AddressError.swift

@@ -1,5 +1,5 @@
 //===----------------------------------------------------------------------===//
-// Copyright © 2025 Apple Inc. and the Containerization project authors.
+// Copyright © 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.
@@ -14,7 +14,7 @@
 // limitations under the License.
 //===----------------------------------------------------------------------===//
 
-public struct IPAddressError: Error, Equatable, Hashable, CustomStringConvertible {
+public struct AddressError: Error, Equatable, Hashable, CustomStringConvertible {
     public var description: String {
         String(describing: self.base)
     }

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.
@@ -27,7 +27,7 @@ public enum IPAddress: Sendable, Hashable, CustomStringConvertible, Equatable {
     ///
     /// - Parameter string: IP address string to parse
     /// - Returns: An `IPAddress` containing either an IPv4 or IPv6 address
-    /// - Throws: `IPAddressError.unableToParse` if invalid
+    /// - Throws: `AddressError.unableToParse` if invalid
     public init(_ string: String) throws {
         let utf8 = string.utf8
         var hasColon = false
@@ -50,7 +50,7 @@ public enum IPAddress: Sendable, Hashable, CustomStringConvertible, Equatable {
             let ipv4 = try IPv4Address(string)
             self = .v4(ipv4)
         } else {
-            throw IPAddressError.unableToParse
+            throw AddressError.unableToParse
         }
     }
 
@@ -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)
+    }
+}

Sources/ContainerizationExtras/IPv4Address.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.
@@ -26,7 +26,7 @@ public struct IPv4Address: Sendable, Hashable, CustomStringConvertible, Equatabl
     /// Creates an IPv4Address from a string representation.
     ///
     /// - Parameter string: The IPv4 address string in dotted decimal notation (e.g., "192.168.1.1")
-    /// - Throws: `IPAddressError.unableToParse` if the string is not a valid IPv4 address
+    /// - Throws: `AddressError.unableToParse` if the string is not a valid IPv4 address
     @inlinable
     public init(_ string: String) throws {
         self.value = try Self.parse(string)
@@ -94,15 +94,15 @@ public struct IPv4Address: Sendable, Hashable, CustomStringConvertible, Equatabl
     @usableFromInline
     internal static func parse(_ s: String) throws -> UInt32 {
         guard !s.isEmpty, s.count >= 7, s.count <= 15 else {
-            throw IPAddressError.unableToParse
+            throw AddressError.unableToParse
         }
 
         // IP addresses should only contain ASCII digits and dots
         let utf8 = s.utf8
         for byte in utf8 {
             // ASCII whitespace: space(32), tab(9), newline(10), return(13)
             if byte == 32 || byte == 9 || byte == 10 || byte == 13 {
-                throw IPAddressError.unableToParse
+                throw AddressError.unableToParse
             }
         }
 
@@ -120,7 +120,7 @@ public struct IPv4Address: Sendable, Hashable, CustomStringConvertible, Equatabl
             if byte == 46 {  // ASCII '.'
                 // Validate octet before processing
                 guard octetCount < 3, digitCount > 0, digitCount <= 3, currentOctet <= 255 else {
-                    throw IPAddressError.unableToParse
+                    throw AddressError.unableToParse
                 }
 
                 // Shift result and add current octet
@@ -143,25 +143,25 @@ public struct IPv4Address: Sendable, Hashable, CustomStringConvertible, Equatabl
                     currentOctet = 0
                 } else if digitCount > 1 && currentOctet == 0 {
                     // We had a leading zero and now have more digits - invalid
-                    throw IPAddressError.unableToParse
+                    throw AddressError.unableToParse
                 } else {
                     // Normal case: build the octet value
                     currentOctet = currentOctet * 10 + digit
                 }
 
                 // Early termination if octet becomes too large
                 guard currentOctet <= 255, digitCount <= 3 else {
-                    throw IPAddressError.unableToParse
+                    throw AddressError.unableToParse
                 }
 
             } else {
-                throw IPAddressError.unableToParse
+                throw AddressError.unableToParse
             }
         }
 
         // Validate final octet
         guard octetCount == 3, digitCount > 0, digitCount <= 3, currentOctet <= 255 else {
-            throw IPAddressError.unableToParse
+            throw AddressError.unableToParse
         }
 
         return (result << 8) | UInt32(currentOctet)