Initialize OpenVPN adapter and establish connection

OpenVPN Tunnel Provider/PacketTunnelProvider.swift

@@ -7,11 +7,61 @@
 //
 
 import NetworkExtension
+import KeychainAccess
+
+enum PacketTunnelProviderError: Error {
+    
+    case startFailure(message: String)
+    
+}
 
 class PacketTunnelProvider: NEPacketTunnelProvider {
     
+    let keychain = Keychain(service: "me.ss-abramchuk.openvpn-ios-client", accessGroup: "2TWXCGG7R3.keychain-shared")
+    
+    var vpnAdapter: OpenVPNAdapter?
+    
+    var startHandler: ((Error?) -> Void)?
+    var stopHandler: (() -> Void)?
+    
     override func startTunnel(options: [String : NSObject]? = nil, completionHandler: @escaping (Error?) -> Void) {
-        // TODO: Some
+        guard let settings = options?["Settings"] as? Data else {
+            let error = PacketTunnelProviderError.startFailure(message: "Failed to retrieve OpenVPN settings from options")
+            completionHandler(error)
+            
+            return
+        }
+        
+        vpnAdapter = OpenVPNAdapter()
+        vpnAdapter?.delegate = self
+        
+        if let username = protocolConfiguration.username {
+            vpnAdapter?.username = username
+        }
+        
+        if let reference = protocolConfiguration.passwordReference {
+            do {
+                guard let password = try keychain.get(ref: reference) else {
+                    throw PacketTunnelProviderError.startFailure(message: "Failed to retrieve password from keychain")
+                }
+                
+                vpnAdapter?.password = password
+            } catch {
+                completionHandler(error)
+                return
+            }
+        }
+        
+        do {
+            try vpnAdapter?.configure(using: settings)
+        } catch {
+            completionHandler(error)
+            return
+        }
+        
+        startHandler = completionHandler
+
+        vpnAdapter?.connect()
     }
     
     override func stopTunnel(with reason: NEProviderStopReason, completionHandler: @escaping () -> Void) {
@@ -19,3 +69,21 @@ class PacketTunnelProvider: NEPacketTunnelProvider {
     }
     
 }
+
+extension PacketTunnelProvider: OpenVPNAdapterDelegate {
+    
+    func configureTunnel(settings: NEPacketTunnelNetworkSettings, callback: @escaping (NEPacketTunnelFlow?) -> Void) {
+        setTunnelNetworkSettings(settings) { (error) in
+            callback(error == nil ? self.packetFlow : nil)
+        }
+    }
+    
+    func handle(event: OpenVPNEvent, message: String?) {
+        
+    }
+    
+    func handle(error: Error) {
+        
+    }
+    
+}