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Treat messages as data

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This commit is contained in:
Christoph Hagen 2023-08-09 16:26:07 +02:00
parent 5d4adf8b15
commit 107b609aea
8 changed files with 53 additions and 345 deletions
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97
Sources/App/API/DeviceResponse.swift
View File

@ -1,97 +0,0 @@
import Foundation
import NIOCore
/**
Encapsulates a response from a device.
*/
struct DeviceResponse {
/// Shorthand property for a timeout event.
static var deviceTimedOut: DeviceResponse {
.init(event: .deviceTimedOut)
}
/// Shorthand property for a disconnected event.
static var deviceNotConnected: DeviceResponse {
.init(event: .deviceNotConnected)
}
/// Shorthand property for a connected event.
static var deviceConnected: DeviceResponse {
.init(event: .deviceConnected)
}
/// Shorthand property for an unexpected socket event.
static var unexpectedSocketEvent: DeviceResponse {
.init(event: .unexpectedSocketEvent)
}
/// Shorthand property for an invalid message.
static var invalidMessageData: DeviceResponse {
.init(event: .invalidMessageData)
}
/// Shorthand property for missing body data.
static var noBodyData: DeviceResponse {
.init(event: .noBodyData)
}
/// Shorthand property for a busy connection
static var operationInProgress: DeviceResponse {
.init(event: .operationInProgress)
}
/// The response to a key from the server
let event: MessageResult
/// The index of the next key to use
let response: Message?
/**
Decode a message from a buffer.
The buffer must contain `Message.length+1` bytes. The first byte denotes the event type,
the remaining bytes contain the message.
- Parameter buffer: The buffer where the message bytes are stored
*/
init?(_ data: Data, request: String) {
guard let byte = data.first else {
log("\(request): No bytes received from device")
return nil
}
guard let event = MessageResult(rawValue: byte) else {
log("\(request): Unknown response \(byte) received from device")
return nil
}
self.event = event
let messageData = data.dropFirst()
guard !messageData.isEmpty else {
// TODO: Check if event should have response message
self.response = nil
return
}
guard messageData.count == Message.length else {
log("\(request): Insufficient message data received from device (expected \(Message.length), got \(messageData.count))")
self.response = nil
return
}
self.response = Message(decodeFrom: data)
}
/**
Create a response from an event without a message from the device.
- Parameter event: The response from the device.
*/
init(event: MessageResult) {
self.event = event
self.response = nil
}
/// Get the reponse encoded in bytes.
var encoded: Data {
guard let message = response else {
return Data([event.rawValue])
}
return Data([event.rawValue]) + message.encoded
}
}

179
Sources/App/API/Message.swift
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@ -1,179 +0,0 @@
import Foundation
import NIOCore
#if canImport(CryptoKit)
import CryptoKit
#else
import Crypto
#endif
/**
An authenticated message to or from the device.
*/
struct Message: Equatable, Hashable {
/// The message authentication code for the message (32 bytes)
let mac: Data
/// The message content
let content: Content
/**
Create an authenticated message
- Parameter mac: The message authentication code
- Parameter content: The message content
*/
init(mac: Data, content: Content) {
self.mac = mac
self.content = content
}
}
extension Message: Codable {
enum CodingKeys: Int, CodingKey {
case mac = 1
case content = 2
}
}
extension Message {
/**
The message content without authentication.
*/
struct Content: Equatable, Hashable {
/// The time of message creation, in UNIX time (seconds since 1970)
let time: UInt32
/// The counter of the message (for freshness)
let id: UInt32
let deviceId: UInt8?
/**
Create new message content.
- Parameter time: The time of message creation,
- Parameter id: The counter of the message
*/
init(time: UInt32, id: UInt32, device: UInt8) {
self.time = time
self.id = id
self.deviceId = device
}
/**
Decode message content from data.
The data consists of two `UInt32` encoded in little endian format
- Warning: The sequence must contain at least 8 bytes, or the function will crash.
- Parameter data: The sequence containing the bytes.
*/
init<T: Sequence>(decodeFrom data: T) where T.Element == UInt8 {
self.time = UInt32(data: Data(data.prefix(MemoryLayout<UInt32>.size)))
self.id = UInt32(data: Data(data.dropLast().suffix(MemoryLayout<UInt32>.size)))
self.deviceId = data.suffix(1).last!
}
/// The byte length of an encoded message content
static var length: Int {
MemoryLayout<UInt32>.size * 2 + 1
}
/// The message content encoded to data
var encoded: Data {
time.encoded + id.encoded + Data([deviceId ?? 0])
}
}
}
extension Message.Content: Codable {
enum CodingKeys: Int, CodingKey {
case time = 1
case id = 2
case deviceId = 3
}
}
extension Message {
/// The length of a message in bytes
static var length: Int {
SHA256.byteCount + Content.length
}
/**
Decode a message from a byte buffer.
The buffer must contain at least `Message.length` bytes, or it will return `nil`.
- Parameter buffer: The buffer containing the bytes.
*/
init?(decodeFrom buffer: ByteBuffer) {
guard let data = buffer.getBytes(at: 0, length: Message.length) else {
return nil
}
self.init(decodeFrom: data)
}
init?(decodeFrom data: Data, index: inout Int) {
guard index + Message.length <= data.count else {
return nil
}
self.init(decodeFrom: data.advanced(by: index))
index += Message.length
}
/// The message encoded to data
var encoded: Data {
mac + content.encoded
}
var bytes: [UInt8] {
Array(encoded)
}
/**
Create a message from received bytes.
- Parameter data: The sequence of bytes
- Note: The sequence must contain at least `Message.length` bytes, or the function will crash.
*/
init<T: Sequence>(decodeFrom data: T) where T.Element == UInt8 {
let count = SHA256.byteCount
self.mac = Data(data.prefix(count))
self.content = .init(decodeFrom: Array(data.dropFirst(count)))
}
/**
Check if the message contains a valid authentication code
- Parameter key: The key used to sign the message.
- Returns: `true`, if the message is valid.
*/
func isValid(using key: SymmetricKey) -> Bool {
HMAC<SHA256>.isValidAuthenticationCode(mac, authenticating: content.encoded, using: key)
}
}
extension Message.Content {
/**
Calculate an authentication code for the message content.
- Parameter key: The key to use to sign the content.
- Returns: The new message signed with the key.
*/
func authenticate(using key: SymmetricKey) -> Message {
let mac = HMAC<SHA256>.authenticationCode(for: encoded, using: key)
return .init(mac: Data(mac.map { $0 }), content: self)
}
/**
Calculate an authentication code for the message content and convert everything to data.
- Parameter key: The key to use to sign the content.
- Returns: The new message signed with the key, serialized to bytes.
*/
func authenticateAndSerialize(using key: SymmetricKey) -> Data {
let encoded = self.encoded
let mac = HMAC<SHA256>.authenticationCode(for: encoded, using: key)
return Data(mac.map { $0 }) + encoded
}
}

21
Sources/App/API/MessageResult.swift
View File

@ -11,8 +11,8 @@ enum MessageResult: UInt8 {
/// A socket event on the device was unexpected (not binary data)
case unexpectedSocketEvent = 2
/// The size of the payload (i.e. message) was invalid, or the data could not be read
case invalidMessageData = 3
/// The size of the payload (i.e. message) was invalid
case invalidMessageSize = 3
/// The transmitted message could not be authenticated using the key
case messageAuthenticationFailed = 4
@ -44,6 +44,10 @@ enum MessageResult: UInt8 {
/// The device is connected
case deviceConnected = 15
case invalidUrlParameter = 20
case invalidResponseAuthentication = 21
}
extension MessageResult: CustomStringConvertible {
@ -54,7 +58,7 @@ extension MessageResult: CustomStringConvertible {
return "The device received unexpected text"
case .unexpectedSocketEvent:
return "Unexpected socket event for the device"
case .invalidMessageData:
case .invalidMessageSize:
return "Invalid message data"
case .messageAuthenticationFailed:
return "Message authentication failed"
@ -76,6 +80,17 @@ extension MessageResult: CustomStringConvertible {
return "Another operation is in progress"
case .deviceConnected:
return "The device is connected"
case .invalidUrlParameter:
return "The url parameter could not be found"
case .invalidResponseAuthentication:
return "The response could not be authenticated"
}
}
}
extension MessageResult {
var encoded: Data {
Data([rawValue])
}
}

17
Sources/App/API/ServerMessage.swift
View File

@ -11,11 +11,11 @@ struct ServerMessage {
static let authTokenSize = SHA256.byteCount
static let length = authTokenSize + Message.length
static let maxLength = authTokenSize + 200
let authToken: Data
let message: Message
let message: Data
/**
Decode a message from a byte buffer.
@ -23,15 +23,16 @@ struct ServerMessage {
- Parameter buffer: The buffer containing the bytes.
*/
init?(decodeFrom buffer: ByteBuffer) {
guard let data = buffer.getBytes(at: 0, length: ServerMessage.length) else {
guard buffer.readableBytes < ServerMessage.maxLength else {
log("Received invalid message with \(buffer.readableBytes) bytes")
return nil
}
guard let data = buffer.getBytes(at: 0, length: buffer.readableBytes) else {
log("Failed to read bytes of received message")
return nil
}
self.authToken = Data(data.prefix(ServerMessage.authTokenSize))
self.message = Message(decodeFrom: Data(data.dropFirst(ServerMessage.authTokenSize)))
}
var encoded: Data {
authToken + message.encoded
self.message = Data(data.dropFirst(ServerMessage.authTokenSize))
}
static func token(from buffer: ByteBuffer) -> Data? {

18
Sources/App/DeviceManager.swift
View File

@ -31,7 +31,7 @@ final class DeviceManager {
}
/// A promise to finish the request once the device responds or times out
private var requestInProgress: EventLoopPromise<DeviceResponse>?
private var requestInProgress: EventLoopPromise<Data>?
init(deviceKey: Data, remoteKey: Data, deviceTimeout: Int64) async {
self.deviceKey = deviceKey
@ -66,24 +66,25 @@ final class DeviceManager {
deviceIsConnected ? "1" : "0"
}
func sendMessageToDevice(_ message: Message, on eventLoop: EventLoop) -> EventLoopFuture<DeviceResponse> {
func sendMessageToDevice(_ message: Data, on eventLoop: EventLoop) -> EventLoopFuture<Data> {
guard let socket = connection, !socket.isClosed else {
connection = nil
return eventLoop.makeSucceededFuture(.deviceNotConnected)
return eventLoop.makeSucceededFuture(MessageResult.deviceNotConnected.encoded)
}
guard requestInProgress == nil else {
return eventLoop.makeSucceededFuture(.operationInProgress)
return eventLoop.makeSucceededFuture(MessageResult.operationInProgress.encoded)
}
let result = eventLoop.makePromise(of: DeviceResponse.self)
let result = eventLoop.makePromise(of: Data.self)
self.requestInProgress = result
socket.send(message.bytes, promise: nil)
socket.send(Array(message), promise: nil)
updateMessageCountMetric()
eventLoop.scheduleTask(in: .seconds(deviceTimeout)) { [weak self] in
guard let promise = self?.requestInProgress else {
return
}
self?.requestInProgress = nil
promise.succeed(.deviceTimedOut)
log("Timed out waiting for device response")
promise.succeed(MessageResult.deviceTimedOut.encoded)
}
return result.futureResult
}
@ -116,9 +117,8 @@ final class DeviceManager {
return
}
defer { requestInProgress = nil }
let response = DeviceResponse(data, request: RouteAPI.socket.rawValue) ?? .unexpectedSocketEvent
log("Device response received")
promise.succeed(response)
promise.succeed(data)
}
func didCloseDeviceSocket() {

8
Sources/App/configure.swift
View File

@ -8,6 +8,13 @@ enum ServerError: Error {
case invalidAuthenticationToken
}
private let dateFormatter: DateFormatter = {
let df = DateFormatter()
df.dateStyle = .short
df.timeStyle = .short
return df
}()
// configures your application
public func configure(_ app: Application) async throws {
let storageFolder = URL(fileURLWithPath: app.directory.resourcesDirectory)
@ -50,6 +57,7 @@ public func configure(_ app: Application) async throws {
}
try await status.update(.nominal)
print("[\(dateFormatter.string(from: Date()))] Server started")
}
private func loadKeys(at url: URL) throws -> (deviceKey: Data, remoteKey: Data) {

18
Sources/App/routes.swift
View File

@ -11,28 +11,28 @@ extension RouteAPI {
}
}
private func messageTransmission(_ req: Request) -> EventLoopFuture<DeviceResponse> {
private func messageTransmission(_ req: Request) -> EventLoopFuture<Data> {
guard let body = req.body.data else {
return req.eventLoop.makeSucceededFuture(.noBodyData)
return req.eventLoop.makeSucceededFuture(MessageResult.noBodyData.encoded)
}
guard let message = ServerMessage(decodeFrom: body) else {
return req.eventLoop.makeSucceededFuture(.invalidMessageData)
return req.eventLoop.makeSucceededFuture(MessageResult.invalidMessageSize.encoded)
}
guard deviceManager.authenticateRemote(message.authToken) else {
return req.eventLoop.makeSucceededFuture(.invalidMessageData)
return req.eventLoop.makeSucceededFuture(MessageResult.messageAuthenticationFailed.encoded)
}
return deviceManager.sendMessageToDevice(message.message, on: req.eventLoop)
}
private func deviceStatus(_ req: Request) -> EventLoopFuture<DeviceResponse> {
private func deviceStatus(_ req: Request) -> EventLoopFuture<MessageResult> {
guard let body = req.body.data else {
return req.eventLoop.makeSucceededFuture(.noBodyData)
}
guard let authToken = ServerMessage.token(from: body) else {
return req.eventLoop.makeSucceededFuture(.invalidMessageData)
return req.eventLoop.makeSucceededFuture(.invalidMessageSize)
}
guard deviceManager.authenticateRemote(authToken) else {
return req.eventLoop.makeSucceededFuture(.invalidMessageData)
return req.eventLoop.makeSucceededFuture(.messageAuthenticationFailed)
}
guard deviceManager.deviceIsConnected else {
return req.eventLoop.makeSucceededFuture(.deviceNotConnected)
@ -48,7 +48,7 @@ func routes(_ app: Application) throws {
The request expects the authentication token of the remote in the body data of the POST request.
The request returns one byte of data, which is the raw value of a `MessageResult`.
Possible results are `noBodyData`, `invalidMessageData`, `deviceNotConnected`, `deviceConnected`.
Possible results are `noBodyData`, `invalidMessageSize`, `deviceNotConnected`, `deviceConnected`.
*/
app.post(RouteAPI.getDeviceStatus.path) { req in
deviceStatus(req).map {
@ -66,7 +66,7 @@ func routes(_ app: Application) throws {
*/
app.post(RouteAPI.postMessage.path) { req in
messageTransmission(req).map {
Response(status: .ok, body: .init(data: $0.encoded))
Response(status: .ok, body: .init(data: $0))
}
}

40
Tests/AppTests/AppTests.swift
View File

@ -10,44 +10,4 @@ final class AppTests: XCTestCase {
XCTAssertEqual(input, output)
}
func testEncodingContent() {
let input = Message.Content(time: 1234567890, id: 23456789, device: 0)
let data = Array(input.encoded)
let output = Message.Content(decodeFrom: data)
XCTAssertEqual(input, output)
let data2 = [42, 42] + data
let output2 = Message.Content(decodeFrom: data2[2...])
XCTAssertEqual(input, output2)
}
func testEncodingMessage() {
let input = Message(mac: Data(repeating: 42, count: 32),
content: Message.Content(time: 1234567890, id: 23456789, device: 0))
let data = input.encoded
let buffer = ByteBuffer(data: data)
let output = Message(decodeFrom: buffer)
XCTAssertEqual(input, output)
}
func testSigning() throws {
let key = SymmetricKey(size: .bits256)
let content = Message.Content(time: 1234567890, id: 23456789, device: 0)
let input = content.authenticate(using: key)
XCTAssertTrue(input.isValid(using: key))
let data = content.authenticateAndSerialize(using: key)
let decoded = Message(decodeFrom: ByteBuffer(data: data))
XCTAssertNotNil(decoded)
XCTAssertTrue(decoded!.isValid(using: key))
XCTAssertEqual(decoded!, input)
XCTAssertEqual(content, input.content)
}
func testMessageTransmission() async throws {
let app = Application(.testing)
defer { app.shutdown() }
try await configure(app)
// How to open a socket via request?
}
}