Single Protocol SDK

The Single Protocol SDK is the ideal choice when you plan to implement a specific protocol within your application. This SDK is suitable if you intend to utilize a single protocol throughout your app or if you prefer to handle protocol switching manually within your application's codebase.

API Documentation

To view a complete list of of the available APIs, see API reference.

VPN SDK Integration

Integrating a VPN SDK into your application typically involves a two-step process: setting up the application target and configuring the network extension target. This process is consistent across most VPN SDKs, with one notable exception - IPSecSDK.

Step 1: Application Target Setup

The first step in the integration process is to configure your application target. This involves modifying your app's build settings, linking necessary libraries, and ensuring that your app has the required permissions and entitlements to utilize the VPN functionality.

Step 2: Network Extension Target Setup

The second step is to set up a network extension target. A network extension is a separate process that runs alongside your main application and handles the VPN connection. This step involves creating a new target in your Xcode project, configuring its build settings, and implementing the necessary code to establish and manage the VPN connection.

IPSecSDK Exception

It's worth noting that IPSecSDK is an exception to the typical two-step integration process. IPSecSDK utilizes Apple's internal tunnel implementation, which eliminates the need for you to set up a separate network extension target.

With IPSecSDK, you only need to focus on setting up the application target. The SDK handles the VPN connection internally, simplifying the integration process.

Getting Started with the SDK

To get started with the single protocol SDK, use the configuration below as a starting point. This minimal setup provides the easiest way to initialize the SDK and begin using its features.

When developing for macOS, it is important to note that even though enabling App Groups is not necessary, you must still provide the groupData and ensure that the groupID property has a valid value. The groupID should follow the format "group.example", where "example" is a unique identifier for your app or project.

Configure Using HydraSDK

import VPNApplicationSDK    
// ...

let groupData = VPNGroupData(
    groupID: "group.com.yourcompany.vpnsdk-demo",
    usesSystemExtension: false
)
    
let hydraConfiguration = HydraConfiguration(
    carrierID: "YOUR_CARRIER_ID",
    extensionBundleID: "com.yourcompany.demo-test.app.hydra-extension",
    groupData: groupData,
    fireshieldConfig: FireshieldConfig(
        mode: .disabled,
        groupData: groupData
    )
)

let hydraSDK = HydraSDK(configuration: hydraConfiguration)

Configure Using IPSecSDK

import VPNApplicationSDK
// ...

let iPSecConfiguration = IPSecConfiguration(
    carrierID: "YOUR_CARRIER_ID",
    trafficCountersFetchInterval: 3.0
)

let iPSecSDK = IPSecSDK(configuration: iPSecConfiguration)

In IPSecSDK, providing GroupData is not necessary.

Connecting VPN and obtaining status

To connect VPN use function start(location:completion:) on SDK instance. When VPN is started or an error occurred, completion handler will be called. To obtain VPN connection status you need to subscribe to vpnStateDidChange notification provided by SDK. For example:

NotificationCenter.default.addObserver(forName: .vpnStateDidChange, object: nil, queue: nil) { notification in
    // ...
}

When you receive notification, get updated VPN status from SDK instance state property and handle this status as designed by your app.

While using Hydra you can also switch location using applyLocationIfConnected(:completion:) when VPN is in connected status. It will update location in the same network extension (without killing it and starting new one). This method will return error if VPN is not currently connected.

Using On Demand mode

iOS and macOS, both provide an ability to connect to VPN automatically when certain (preconfigured) coditions are met. This functionality is called On Demand.

VPN SDK can be configured for On Demand mode with corresponding configuration via isOnDemandEnabled and onDemandRules properties. The SDK could be initialized with this parameter.

On Demand and users with limited traffic

If your service provides limited traffic or a transport error occurs (e.g. credentials to VPN nodes are expired), current session will be killed with VPNTunnelError.trafficExceeded error. If On Demand mode conditions are met, the System will try to restart Network Extension process, until it is up and running. Due to NetworkExtension framework's limitation, it is not possible to disable On Demand mode from Custom Tunnel Provider extension upon receiving these errors. This makes System trying endlessly reconnect to VPN, while Network Extension is unable to provide VPN service due to the error.

In order to overcome this issue, VPN SDK disables real tunneling, leaving Network Extension running in Bypass mode. By doing this, iOS can meet On Demand mode conditions while the traffic is routed locally, without VPN server. It means that user will have their real IP address and there will be no traffic protection.

Whenever app starts, it's highly recommended to check if VPN is connected and if user is out of traffic limit. In this case, it's necessary to disconnect current VPN session and optionally show user a message. To check if current VPN connection is running in Bypass mode read isBypassEnabled property from SDK instance.

In order to catch situation when user is out of traffic without main app running, use BaseNetworkExtensionDelegate callback method vpnDidReceiveError(_:).

Error Handling

Most of the SDK instance calls are accepting completion blocks with errors. If some error occurs, you will receive non-nil Error object with an explanation. Some errors types that can be thrown by VPN SDK methods: PartnerAPI.APIError, VPNSDKError, VPNTransportError, VPNTunnelError. If you need localized description make these types conform to LocalizedError protocol and provide var errorDescription: String? property. Then you can use localizedDescription property on returned Error.

If you are just disconnected from VPN session, you could also check lastTunnelError property of SDK instance, if there was an error during network extension initialization or session management system disconnected VPN remotely, there will be VPNTunnelError case here. You can handle such errors and report if appropriate. Pay attention that this property is always nil for IPSecSDK, because we don't have access to internal IPSec implementation.

Crash Reporting

Some project might consider crash reporting integration (such as, Crashlytics) for Network Extension side. If your crash reporting framework supports Application Extensions and requires additional code to setup it, put the configuration code inside BaseNetworkExtensionDelegate's -init override:

import HydraTunnelProvider

class ProviderDelegate: NSObject, BaseNetworkExtensionDelegate {
    override init() {
        Fabric.with([Crashlytics.self])
    }
}