Merge pull request #22 from keeshux/parse-ping-from-push-reply

Parse ping from PUSH_REPLY

TunnelKit/Sources/Core/SessionProxy+PushReply.swift

@@ -150,6 +150,9 @@ public protocol SessionReply {
     /// The optional compression framing.
     var compressionFraming: SessionProxy.CompressionFraming? { get }
     
+    /// The optional keep-alive interval.
+    var ping: Int? { get }
+
     /// The optional authentication token.
     var authToken: String? { get }
     
@@ -191,6 +194,8 @@ extension SessionProxy {
 
         private static let compRegexp = try! NSRegularExpression(pattern: "comp(ress|-lzo)", options: [])
         
+        private static let pingRegexp = try! NSRegularExpression(pattern: "ping \\d+", options: [])
+
         private static let authTokenRegexp = try! NSRegularExpression(pattern: "auth-token [a-zA-Z0-9/=+]+", options: [])
 
         private static let peerIdRegexp = try! NSRegularExpression(pattern: "peer-id [0-9]+", options: [])
@@ -207,6 +212,8 @@ extension SessionProxy {
         
         let compressionFraming: SessionProxy.CompressionFraming?
         
+        let ping: Int?
+        
         let authToken: String?
         
         let peerId: UInt32?
@@ -232,6 +239,7 @@ extension SessionProxy {
 
             var dnsServers: [String] = []
             var compressionFraming: SessionProxy.CompressionFraming?
+            var ping: Int?
             var authToken: String?
             var peerId: UInt32?
             var cipher: SessionProxy.Cipher?
@@ -388,6 +396,12 @@ extension SessionProxy {
                 }
             }
             
+            // MARK: Keep-alive
+            
+            PushReply.pingRegexp.enumerateArguments(in: message) {
+                ping = Int($0[0])
+            }
+            
             // MARK: Authentication
 
             PushReply.authTokenRegexp.enumerateArguments(in: message) {
@@ -406,6 +420,7 @@ extension SessionProxy {
 
             self.dnsServers = dnsServers
             self.compressionFraming = compressionFraming
+            self.ping = ping
             self.authToken = authToken
             self.peerId = peerId
             self.cipher = cipher

TunnelKit/Sources/Core/SessionProxy.swift

@@ -85,6 +85,18 @@ public class SessionProxy {
     
     private let configuration: Configuration
     
+    private var keepAliveInterval: TimeInterval? {
+        let interval: TimeInterval?
+        if let negInterval = pushReply?.ping, negInterval > 0 {
+            interval = TimeInterval(negInterval)
+        } else if let cfgInterval = configuration.keepAliveInterval, cfgInterval > 0.0 {
+            interval = cfgInterval
+        } else {
+            return nil
+        }
+        return interval
+    }
+    
     /// An optional `SessionProxyDelegate` for receiving session events.
     public weak var delegate: SessionProxyDelegate?
     
@@ -583,13 +595,11 @@ public class SessionProxy {
             return
         }
 
-        if let interval = configuration.keepAliveInterval, interval > 0 {
+        // postpone ping if elapsed less than keep-alive
+        if let interval = keepAliveInterval {
             let elapsed = now.timeIntervalSince(lastPingOut)
             guard (elapsed >= interval) else {
-                let remaining = min(interval, interval - elapsed)
-                queue.asyncAfter(deadline: .now() + remaining) { [weak self] in
-                    self?.ping()
-                }
+                scheduleNextPing(elapsed: elapsed)
                 return
             }
         }
@@ -598,10 +608,16 @@ public class SessionProxy {
         sendDataPackets([DataPacket.pingString])
         lastPingOut = Date()
 
-        if let interval = configuration.keepAliveInterval, interval > 0 {
-            queue.asyncAfter(deadline: .now() + interval) { [weak self] in
-                self?.ping()
-            }
+        scheduleNextPing()
+    }
+    
+    private func scheduleNextPing(elapsed: TimeInterval = 0.0) {
+        guard let interval = keepAliveInterval else {
+            return
+        }
+        let remaining = min(interval, interval - elapsed)
+        queue.asyncAfter(deadline: .now() + remaining) { [weak self] in
+            self?.ping()
         }
     }
     
@@ -904,11 +920,7 @@ public class SessionProxy {
         }
         delegate?.sessionDidStart(self, remoteAddress: remoteAddress, reply: reply)
 
-        if let interval = configuration.keepAliveInterval, interval > 0 {
-            queue.asyncAfter(deadline: .now() + interval) { [weak self] in
-                self?.ping()
-            }
-        }
+        scheduleNextPing()
     }
     
     // Ruby: transition_keys
@@ -1040,6 +1052,9 @@ public class SessionProxy {
         if let negFraming = pushedFraming {
             log.debug("Negotiated compression framing: \(negFraming.rawValue)")
         }
+        if let negPing = pushReply.ping {
+            log.debug("Negotiated keep-alive: \(negPing) seconds")
+        }
         let pushedCipher = pushReply.cipher
         if let negCipher = pushedCipher {
             log.debug("Negotiated cipher: \(negCipher.rawValue)")

TunnelKitTests/PushTests.swift

@@ -115,4 +115,12 @@ class PushTests: XCTestCase {
         
         XCTAssertEqual(reply.cipher, .aes256gcm)
     }
+    
+    func testPing() {
+        let msg = "PUSH_REPLY,route 192.168.1.0 255.255.255.0,route 10.0.2.0 255.255.255.0,dhcp-option DNS 192.168.1.99,dhcp-option DNS 176.103.130.130,route 10.0.2.1,topology net30,ping 10,ping-restart 60,ifconfig 10.0.2.14 10.0.2.13"
+        let reply = try! SessionProxy.PushReply(message: msg)!
+        reply.debug()
+        
+        XCTAssertEqual(reply.ping, 10)
+    }
 }