Add ISO socket support

Sources/BluetoothLinux/ISO/ISOFileDescriptor.swift

@@ -0,0 +1,23 @@
+//
+//  ISOFileDescriptor.swift
+//  BluetoothLinux
+//
+
+import Bluetooth
+import Socket
+
+internal extension SocketDescriptor {
+
+    /// Creates an ISO socket binded to the specified address.
+    @usableFromInline
+    static func iso(
+        _ address: ISOSocketAddress,
+        _ flags: SocketFlags
+    ) throws(Errno) -> SocketDescriptor {
+        try bluetooth(
+            .iso,
+            bind: address,
+            flags: flags
+        )
+    }
+}

Sources/BluetoothLinux/ISO/ISOQualityOfService.swift

@@ -0,0 +1,112 @@
+//
+//  ISOQualityOfService.swift
+//  BluetoothLinux
+//
+
+import Bluetooth
+import SystemPackage
+import Socket
+
+public extension BluetoothSocketOption {
+
+    /// Bluetooth Isochronous Channel Quality of Service socket option
+    ///
+    /// Configures the connected isochronous stream parameters of an ISO socket
+    /// (`bt_iso_qos`, unicast). Must be set before the connection is established.
+    struct ISOQualityOfService: Equatable, Hashable, SocketOption, Sendable {
+
+        @_alwaysEmitIntoClient
+        public static var id: BluetoothSocketOption { .isoQualityOfService }
+
+        /// The connected isochronous group identifier (`0xFF` for unset).
+        public var group: UInt8 // cig
+
+        /// The connected isochronous stream identifier (`0xFF` for unset).
+        public var stream: UInt8 // cis
+
+        /// The sleep clock accuracy.
+        public var sleepClockAccuracy: UInt8 // sca
+
+        /// The preferred method of arranging subevents of multiple streams.
+        public var packing: UInt8
+
+        /// The format of the sent data (unframed or framed).
+        public var framing: UInt8
+
+        /// Input (receive) parameters.
+        public var input: IO
+
+        /// Output (send) parameters.
+        public var output: IO
+
+        public init(
+            group: UInt8 = 0xFF,
+            stream: UInt8 = 0xFF,
+            sleepClockAccuracy: UInt8 = 0,
+            packing: UInt8 = 0,
+            framing: UInt8 = 0,
+            input: IO = IO(),
+            output: IO = IO()
+        ) {
+            self.group = group
+            self.stream = stream
+            self.sleepClockAccuracy = sleepClockAccuracy
+            self.packing = packing
+            self.framing = framing
+            self.input = input
+            self.output = output
+        }
+
+        public func withUnsafeBytes<Result, Error>(_ body: ((UnsafeRawBufferPointer) throws(Error) -> (Result))) rethrows -> Result where Error: Swift.Error {
+            return try Swift.withUnsafeBytes(of: self) { bufferPointer in
+                try body(bufferPointer)
+            }
+        }
+
+        public static func withUnsafeBytes<Error>(
+            _ body: (UnsafeMutableRawBufferPointer) throws(Error) -> ()
+        ) rethrows -> Self where Error: Swift.Error {
+            var value = self.init()
+            try Swift.withUnsafeMutableBytes(of: &value, body)
+            return value
+        }
+    }
+}
+
+public extension BluetoothSocketOption.ISOQualityOfService {
+
+    /// Isochronous stream input/output parameters.
+    ///
+    /// `bt_iso_io_qos`
+    struct IO: Equatable, Hashable, Sendable {
+
+        /// SDU interval in microseconds.
+        public var interval: UInt32
+
+        /// Maximum transport latency in milliseconds.
+        public var latency: UInt16
+
+        /// Maximum SDU size in octets.
+        public var sdu: UInt16
+
+        /// PHY to use.
+        public var phy: UInt8
+
+        /// Retransmission number.
+        public var retransmissionNumber: UInt8 // rtn
+
+        public init(
+            interval: UInt32 = 0,
+            latency: UInt16 = 0,
+            sdu: UInt16 = 0,
+            phy: UInt8 = 0,
+            retransmissionNumber: UInt8 = 0
+        ) {
+            self.interval = interval
+            self.latency = latency
+            self.sdu = sdu
+            self.phy = phy
+            self.retransmissionNumber = retransmissionNumber
+        }
+    }
+}

Sources/BluetoothLinux/ISO/ISOSocket.swift

@@ -0,0 +1,165 @@
+//
+//  ISOSocket.swift
+//  BluetoothLinux
+//
+
+import Foundation
+import Bluetooth
+import SystemPackage
+import Socket
+
+/// Bluetooth ISO Socket
+///
+/// Isochronous channels carry time-sensitive audio data between the host
+/// and Low Energy devices (LE Audio). Requires kernel 6.0 or later; on older
+/// kernels the ISO socket is gated behind an experimental feature toggled
+/// via the management interface.
+public struct ISOSocket: Sendable {
+
+    // MARK: - Properties
+
+    @usableFromInline
+    internal let fileDescriptor: SocketDescriptor
+
+    /// Socket address.
+    public let address: ISOSocketAddress
+
+    // MARK: - Initialization
+
+    internal init(
+        fileDescriptor: SocketDescriptor,
+        address: ISOSocketAddress
+    ) {
+        self.fileDescriptor = fileDescriptor
+        self.address = address
+    }
+
+    /// Create a new ISO socket bound to the specified address.
+    public init(address: ISOSocketAddress) throws(Errno) {
+        self.fileDescriptor = try .iso(address, [.closeOnExec, .nonBlocking])
+        self.address = address
+    }
+
+    /// Creates a client socket connected to the specified remote device.
+    ///
+    /// - Note: The quality of service must be configured before connecting
+    ///   when using non-default stream parameters.
+    public static func client(
+        address localAddress: ISOSocketAddress,
+        destination destinationAddress: ISOSocketAddress,
+        qualityOfService: BluetoothSocketOption.ISOQualityOfService? = nil
+    ) throws(Errno) -> Self {
+        let fileDescriptor = try SocketDescriptor.iso(localAddress, [.closeOnExec, .nonBlocking])
+
+        // configure stream parameters before connecting
+        if let qualityOfService {
+            do {
+                try fileDescriptor.setSocketOption(qualityOfService)
+            } catch {
+                try? fileDescriptor.close()
+                throw error
+            }
+        }
+
+        // Start async connect - for non-blocking sockets this returns EINPROGRESS
+        do {
+            try fileDescriptor.connect(to: destinationAddress)
+        } catch Errno.nowInProgress {
+            // Expected for non-blocking socket - connection is in progress
+            // Wait for socket to become writable (indicates connect completed)
+            let timeout: Int = 30_000  // 30 seconds in milliseconds
+            let events = try fileDescriptor.poll(for: [.write, .error, .hangup], timeout: timeout)
+
+            // Check for errors
+            if events.contains(.error) || events.contains(.hangup) {
+                try? fileDescriptor.close()
+                throw Errno.connectionRefused
+            }
+
+            // Check if we timed out (no events returned)
+            if !events.contains(.write) {
+                try? fileDescriptor.close()
+                throw Errno.timedOut
+            }
+        } catch {
+            // Other errors during connect
+            try? fileDescriptor.close()
+            throw error
+        }
+
+        return Self.init(fileDescriptor: fileDescriptor, address: localAddress)
+    }
+
+    /// Creates a server socket listening on the specified address.
+    public static func server(
+        address: ISOSocketAddress,
+        backlog: Int = Socket.maxBacklog
+    ) throws(Errno) -> Self {
+        let fileDescriptor = try SocketDescriptor.iso(address, [.closeOnExec, .nonBlocking])
+        try fileDescriptor.closeIfThrows { () throws(Errno) -> () in
+            try fileDescriptor.listen(backlog: backlog)
+        }
+        return Self.init(fileDescriptor: fileDescriptor, address: address)
+    }
+
+    // MARK: - Methods
+
+    /// Close socket.
+    public func close() {
+        try? fileDescriptor.close()
+    }
+
+    /// Attempt to accept an incoming connection.
+    public func accept() throws(Errno) -> Self {
+        let (fileDescriptor, address) = try self.fileDescriptor.accept(ISOSocketAddress.self)
+        return Self.init(
+            fileDescriptor: fileDescriptor,
+            address: address
+        )
+    }
+
+    /// Write to the socket.
+    public func send(_ data: Data) throws(Errno) -> Int {
+        do {
+            return try data.withUnsafeBytes { (bytes) throws(Errno) -> Int in
+                try fileDescriptor.write(bytes)
+            }
+        }
+        catch {
+            throw error as! Errno // TODO: Foundation doesnt support typed error yet
+        }
+    }
+
+    /// Reads from the socket.
+    public func receive(_ length: Int) throws(Errno) -> Data {
+        do {
+            var data = Data(count: length)
+            let bytesRead = try data.withUnsafeMutableBytes { (bytes) throws(Errno) -> Int in
+                try fileDescriptor.read(into: bytes)
+            }
+            if bytesRead < length {
+                data = data.prefix(bytesRead)
+            }
+            return data
+        }
+        catch {
+            throw error as! Errno // TODO: Foundation doesnt support typed error yet
+        }
+    }
+
+    // MARK: - Options
+
+    /// The quality of service of the socket.
+    public var qualityOfService: BluetoothSocketOption.ISOQualityOfService {
+        get throws(Errno) {
+            try fileDescriptor.getSocketOption(BluetoothSocketOption.ISOQualityOfService.self)
+        }
+    }
+
+    /// Set the quality of service of the socket.
+    ///
+    /// Must be configured before the connection is established.
+    public func setQualityOfService(_ qualityOfService: BluetoothSocketOption.ISOQualityOfService) throws(Errno) {
+        try fileDescriptor.setSocketOption(qualityOfService)
+    }
+}

Sources/BluetoothLinux/ISO/ISOSocketAddress.swift

@@ -0,0 +1,74 @@
+//
+//  ISOSocketAddress.swift
+//  BluetoothLinux
+//
+
+import SystemPackage
+import Socket
+import Bluetooth
+
+/// Bluetooth ISO Socket Address
+@frozen
+public struct ISOSocketAddress: Equatable, Hashable, Sendable {
+
+    // MARK: - Properties
+
+    /// Bluetooth address
+    public var address: BluetoothAddress
+
+    /// Bluetooth address type
+    public var addressType: AddressType
+
+    // MARK: - Initialization
+
+    public init(
+        address: BluetoothAddress,
+        addressType: AddressType = .lowEnergyPublic
+    ) {
+        self.address = address
+        self.addressType = addressType
+    }
+}
+
+extension ISOSocketAddress: BluetoothSocketAddress {
+
+    @_alwaysEmitIntoClient
+    public static var protocolID: BluetoothSocketProtocol { .iso }
+
+    /// Unsafe pointer closure
+    public func withUnsafePointer<Result, Error>(
+      _ body: (UnsafePointer<CInterop.SocketAddress>, UInt32) throws(Error) -> Result
+    ) rethrows -> Result where Error: Swift.Error {
+        var value = CInterop.ISOSocketAddress()
+        value.address = address.littleEndian
+        value.type = addressType.rawValue
+        return try value.withUnsafePointer(body)
+    }
+
+    public static func withUnsafePointer<Error>(
+        _ body: (UnsafeMutablePointer<CInterop.SocketAddress>, UInt32) throws(Error) -> ()
+    ) rethrows -> Self where Error: Swift.Error {
+        var value = CInterop.ISOSocketAddress()
+        try value.withUnsafeMutablePointer(body)
+        return Self.init(value)
+    }
+
+    public static func withUnsafePointer(
+        _ pointer: UnsafeMutablePointer<CInterop.SocketAddress>
+    ) -> Self {
+        pointer.withMemoryRebound(to: CInterop.ISOSocketAddress.self, capacity: 1) { pointer in
+            Self.init(pointer.pointee)
+        }
+    }
+}
+
+internal extension ISOSocketAddress {
+
+    @usableFromInline
+    init(_ bytes: CInterop.ISOSocketAddress) {
+        self.init(
+            address: .init(littleEndian: bytes.address),
+            addressType: AddressType(rawValue: bytes.type) ?? .lowEnergyPublic
+        )
+    }
+}