Merge pull request #19 from keeshux/parse-compression-framing-from-push-reply

Parse compression framing from PUSH_REPLY

TunnelKit/Sources/Core/SessionProxy+PushReply.swift

@@ -147,6 +147,9 @@ public protocol SessionReply {
     /// The DNS servers set up for this session.
     var dnsServers: [String] { get }
     
+    /// The optional compression framing.
+    var compressionFraming: SessionProxy.CompressionFraming? { get }
+    
     /// The optional authentication token.
     var authToken: String? { get }
     
@@ -186,6 +189,8 @@ extension SessionProxy {
 
         private static let dnsRegexp = try! NSRegularExpression(pattern: "dhcp-option DNS6? [\\d\\.a-fA-F:]+", options: [])
 
+        private static let compRegexp = try! NSRegularExpression(pattern: "comp(ress|-lzo)", 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: [])
@@ -200,6 +205,8 @@ extension SessionProxy {
         
         let dnsServers: [String]
         
+        let compressionFraming: SessionProxy.CompressionFraming?
+        
         let authToken: String?
         
         let peerId: UInt32?
@@ -224,6 +231,7 @@ extension SessionProxy {
             var optIfconfig6Arguments: [String]?
 
             var dnsServers: [String] = []
+            var compressionFraming: SessionProxy.CompressionFraming?
             var authToken: String?
             var peerId: UInt32?
             var cipher: SessionProxy.Cipher?
@@ -365,6 +373,21 @@ extension SessionProxy {
                 dnsServers.append($0[1])
             }
             
+            // MARK: Compression
+            
+            PushReply.compRegexp.enumerateComponents(in: message) {
+                switch $0[0] {
+                case "comp-lzo":
+                    compressionFraming = .compLZO
+                    
+                case "compress":
+                    compressionFraming = .compress
+                    
+                default:
+                    break
+                }
+            }
+            
             // MARK: Authentication
 
             PushReply.authTokenRegexp.enumerateArguments(in: message) {
@@ -382,6 +405,7 @@ extension SessionProxy {
             }
 
             self.dnsServers = dnsServers
+            self.compressionFraming = compressionFraming
             self.authToken = authToken
             self.peerId = peerId
             self.cipher = cipher
@@ -404,13 +428,20 @@ extension SessionProxy {
 
 private extension NSRegularExpression {
     func enumerateArguments(in string: String, using block: ([String]) -> Void) {
+        enumerateComponents(in: string) { (tokens) in
+            var args = tokens
+            args.removeFirst()
+            block(args)
+        }
+    }
+
+    func enumerateComponents(in string: String, using block: ([String]) -> Void) {
         enumerateMatches(in: string, options: [], range: NSMakeRange(0, string.count)) { (result, flags, stop) in
             guard let range = result?.range else {
                 return
             }
             let match = (string as NSString).substring(with: range)
-            var tokens = match.components(separatedBy: " ")
-            tokens.removeFirst()
+            let tokens = match.components(separatedBy: " ")
             block(tokens)
         }
     }

TunnelKit/Sources/Core/SessionProxy.swift

@@ -1031,6 +1031,10 @@ public class SessionProxy {
             log.debug("Set up encryption")
         }
         
+        let pushedFraming = pushReply.compressionFraming
+        if let negFraming = pushedFraming {
+            log.debug("Negotiated compression framing: \(negFraming.rawValue)")
+        }
         let pushedCipher = pushReply.cipher
         if let negCipher = pushedCipher {
             log.debug("Negotiated cipher: \(negCipher.rawValue)")
@@ -1054,7 +1058,7 @@ public class SessionProxy {
             encrypter: bridge.encrypter(),
             decrypter: bridge.decrypter(),
             peerId: pushReply.peerId ?? PacketPeerIdDisabled,
-            compressionFraming: configuration.compressionFraming.native,
+            compressionFraming: (pushedFraming ?? configuration.compressionFraming).native,
             maxPackets: link?.packetBufferSize ?? 200,
             usesReplayProtection: CoreConfiguration.usesReplayProtection
         )

TunnelKitTests/PushTests.swift

@@ -92,11 +92,19 @@ class PushTests: XCTestCase {
         XCTAssertEqual(reply.dnsServers, ["2001:4860:4860::8888", "2001:4860:4860::8844"])
     }
     
-    func testNCP() {
+    func testCompressionFraming() {
         let msg = "PUSH_REPLY,dhcp-option DNS 8.8.8.8,dhcp-option DNS 4.4.4.4,comp-lzo no,route 10.8.0.1,topology net30,ping 10,ping-restart 120,ifconfig 10.8.0.6 10.8.0.5,peer-id 0,cipher AES-256-CBC"
         let reply = try! SessionProxy.PushReply(message: msg)!
         reply.debug()
         
+        XCTAssertEqual(reply.compressionFraming, .compLZO)
+    }
+    
+    func testNCP() {
+        let msg = "PUSH_REPLY,dhcp-option DNS 8.8.8.8,dhcp-option DNS 4.4.4.4,comp-lzo no,route 10.8.0.1,topology net30,ping 10,ping-restart 120,ifconfig 10.8.0.6 10.8.0.5,peer-id 0,cipher AES-256-GCM"
+        let reply = try! SessionProxy.PushReply(message: msg)!
+        reply.debug()
+
         XCTAssertEqual(reply.cipher, .aes256gcm)
     }