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Test path snodes for reliability as well

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pull/148/head
gmbnt 5 years ago
parent c67e2af9a6
commit 1f3d13ee3b
1 changed files with 38 additions and 40 deletions
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68
SignalServiceKit/src/Loki/API/Onion Requests/OnionRequestAPI.swift
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@ -1,8 +1,6 @@
import CryptoSwift
import PromiseKit
// TODO: Test path snodes as well
/// See the "Onion Requests" section of [The Session Whitepaper](https://arxiv.org/pdf/2002.04609.pdf) for more information.
internal enum OnionRequestAPI {
private static let urlSession = URLSession(configuration: .ephemeral, delegate: urlSessionDelegate, delegateQueue: nil)
@ -70,8 +68,8 @@ internal enum OnionRequestAPI {
private typealias OnionBuildingResult = (guardSnode: LokiAPITarget, encryptionResult: EncryptionResult, symmetricKey: Data)
// MARK: Private API
private static func execute(_ verb: HTTPVerb, _ url: String, parameters: JSON? = nil, timeout: TimeInterval = OnionRequestAPI.timeout) -> Promise<Any> {
return Promise<Any> { seal in
private static func execute(_ verb: HTTPVerb, _ url: String, parameters: JSON? = nil, timeout: TimeInterval = OnionRequestAPI.timeout) -> Promise<JSON> {
return Promise<JSON> { seal in
let url = URL(string: url)!
var request = URLRequest(url: url)
request.httpMethod = verb.rawValue
@ -94,27 +92,23 @@ internal enum OnionRequestAPI {
return seal.reject(error)
}
let statusCode = UInt(response.statusCode)
guard 200...299 ~= statusCode else {
var json: JSON? = nil
if let j = try? JSONSerialization.jsonObject(with: data, options: []) as? JSON {
json = j
} else if let result = String(data: data, encoding: .utf8) {
json = [ "result" : result ]
}
guard 200...299 ~= statusCode else {
let jsonDescription = json?.prettifiedDescription ?? "no debugging info provided"
print("[Loki] [Onion Request API] \(verb.rawValue) request to \(url) failed with status code: \(statusCode) (\(jsonDescription)).")
return seal.reject(Error.httpRequestFailed(statusCode: statusCode, json: json))
}
var json: JSON! = nil
if let j = try? JSONSerialization.jsonObject(with: data, options: []) as? JSON {
json = j
} else if let result = String(data: data, encoding: .utf8) {
json = [ "result" : result ]
if let json = json {
seal.fulfill(json)
} else {
print("[Loki] [Onion Request API] Couldn't parse JSON returned by \(verb.rawValue) request to \(url).")
return seal.reject(Error.invalidJSON)
}
seal.fulfill(json!)
}
task.resume()
}
@ -125,9 +119,8 @@ internal enum OnionRequestAPI {
let (promise, seal) = Promise<Void>.pending()
let queue = DispatchQueue(label: UUID().uuidString, qos: .userInitiated) // No need to block the work queue for this
queue.async {
print("[Loki] [Onion Request API] Testing snode: \(snode).")
let url = "\(snode.address):\(snode.port)/get_stats/v1"
let timeout: TimeInterval = 10 // Use a shorter timeout for testing
let timeout: TimeInterval = 6 // Use a shorter timeout for testing
execute(.get, url, timeout: timeout).done(on: queue) { rawResponse in
guard let json = rawResponse as? JSON, let version = json["version"] as? String else { return seal.reject(Error.missingSnodeVersion) }
if version >= "2.0.0" {
@ -146,31 +139,22 @@ internal enum OnionRequestAPI {
/// Finds `guardSnodeCount` guard snodes to use for path building. The returned promise errors out with `Error.insufficientSnodes`
/// if not enough (reliable) snodes are available.
private static func getGuardSnodes() -> Promise<Set<LokiAPITarget>> {
if !guardSnodes.isEmpty {
if guardSnodes.count >= guardSnodeCount {
return Promise<Set<LokiAPITarget>> { $0.fulfill(guardSnodes) }
} else {
print("[Loki] [Onion Request API] Populating guard snode cache.")
return LokiAPI.getRandomSnode().then(on: workQueue) { _ -> Promise<Set<LokiAPITarget>> in // Just used to populate the snode pool
let snodePool = LokiAPI.randomSnodePool
guard !snodePool.isEmpty else { throw Error.insufficientSnodes }
var result: Set<LokiAPITarget> = [] // Sync on DispatchQueue.global()
var unusedSnodes = LokiAPI.randomSnodePool // Sync on workQueue
guard unusedSnodes.count >= guardSnodeCount else { throw Error.insufficientSnodes }
func getGuardSnode() -> Promise<LokiAPITarget> {
// randomElement() uses the system's default random generator, which is cryptographically secure
guard let candidate = snodePool.randomElement() else { return Promise<LokiAPITarget> { $0.reject(Error.insufficientSnodes) } }
guard let candidate = unusedSnodes.randomElement() else { return Promise<LokiAPITarget> { $0.reject(Error.insufficientSnodes) } }
unusedSnodes.remove(candidate)
print("[Loki] [Onion Request API] Testing guard snode: \(candidate).")
// Loop until a reliable guard snode is found
return testSnode(candidate).map(on: workQueue) { candidate }.recover(on: workQueue) { _ in getGuardSnode() }
}
func getAndStoreGuardSnode() -> Promise<LokiAPITarget> {
return getGuardSnode().then(on: workQueue) { guardSnode -> Promise<LokiAPITarget> in
if !result.contains(guardSnode) {
result.insert(guardSnode)
return Promise { $0.fulfill(guardSnode) }
} else {
return getAndStoreGuardSnode()
}
}
}
let promises = (0..<guardSnodeCount).map { _ in getAndStoreGuardSnode() }
let promises = (0..<guardSnodeCount).map { _ in getGuardSnode() }
return when(fulfilled: promises).map(on: workQueue) { guardSnodes in
let guardSnodesAsSet = Set(guardSnodes)
OnionRequestAPI.guardSnodes = guardSnodesAsSet
@ -186,18 +170,32 @@ internal enum OnionRequestAPI {
print("[Loki] [Onion Request API] Building onion request paths.")
return LokiAPI.getRandomSnode().then(on: workQueue) { _ -> Promise<Set<Path>> in // Just used to populate the snode pool
let snodePool = LokiAPI.randomSnodePool
return getGuardSnodes().map(on: workQueue) { guardSnodes in
var unusedSnodes = snodePool.subtracting(guardSnodes)
return getGuardSnodes().then(on: workQueue) { guardSnodes -> Promise<Set<LokiAPITarget>> in
var unusedSnodes = snodePool.subtracting(guardSnodes) // Sync on workQueue
let minSnodeCount = guardSnodeCount * pathSize - guardSnodeCount
guard unusedSnodes.count >= minSnodeCount else { throw Error.insufficientSnodes }
let result: Set<Path> = Set(guardSnodes.map { guardSnode in
// Force unwrapping is safe because of the minSnodeCount check above
func getPathSnode() -> Promise<LokiAPITarget> {
// randomElement() uses the system's default random generator, which is cryptographically secure
let result = [ guardSnode ] + (0..<(pathSize - 1)).map { _ in unusedSnodes.randomElement()! }
guard let candidate = unusedSnodes.randomElement() else { return Promise<LokiAPITarget> { $0.reject(Error.insufficientSnodes) } }
unusedSnodes.remove(candidate)
print("[Loki] [Onion Request API] Testing path snode: \(candidate).")
// Loop until a reliable guard snode is found
return testSnode(candidate).map(on: workQueue) { candidate }.recover(on: workQueue) { _ in getPathSnode() }
}
let promises = (0..<guardSnodeCount).map { _ in getPathSnode() }
return when(fulfilled: promises).map(on: workQueue) { Set($0) }
}.map(on: workQueue) { pathSnodes in
var pathSnodes = pathSnodes
return Set(guardSnodes.map { guardSnode in
let result = [ guardSnode ] + (0..<(pathSize - 1)).map { _ in
// randomElement() uses the system's default random generator, which is cryptographically secure
let pathSnode = pathSnodes.randomElement()! // Safe because of the minSnodeCount check above
pathSnodes.remove(pathSnode)
return pathSnode
}
print("[Loki] [Onion Request API] Built new onion request path: \(result.prettifiedDescription).")
return result
})
return result
}
}
}

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