How to detect if the internet connection is over WiFi or Ethernet?

Question

Is there a way to open network settings programmatically? Closest thing I know is opening the main settings page:

let settingsURL = NSURL(string: UIApplicationOpenSettingsURLString)!
UIApplication.sharedApplication().openURL(settingsURL)

I want to be able to detect if the internet connection is over WiFi or Ethernet.

Answer 1

The way to detect this is to look at the name of the network interfaces. For Mac and Apple TV, en0 and en1 refer to the wired and wireless interfaces respectively.

Add this to your bridging header (or create one if needed):

#include <ifaddrs.h>
#include <net/if_dl.h>

Then use this Swift code to get the information you need:

struct Networking {

    enum NetworkInterfaceType: String, CustomStringConvertible {
        case Ethernet = "en0"
        case Wifi = "en1"
        case Unknown = ""

        var description: String {
            switch self {
            case .Ethernet:
                return "Ethernet"
            case .Wifi:
                return "Wifi"
            case .Unknown:
                return "Unknown"
            }
        }
    }

    static var networkInterfaceType: NetworkInterfaceType {
        if let name = Networking().getInterfaces().first?.name, let type = NetworkInterfaceType(rawValue: name) {
            return type
        }

        return .Unknown
    }

    static var isConnectedByEthernet: Bool {
        let networking = Networking()
        for addr in networking.getInterfaces() {
            if addr.name == NetworkInterfaceType.Ethernet.rawValue {
                return true
            }
        }
        return false
    }

    static var isConnectedByWiFi: Bool {
        let networking = Networking()
        for addr in networking.getInterfaces() {
            if addr.name == NetworkInterfaceType.Wifi.rawValue {
                return true
            }
        }
        return false
    }

    // Credit to Martin R http://stackoverflow.com/a/34016247/600753 for this lovely code
    // New Swift 3 implementation needed upated to replace unsafepointer calls with .withMemoryRebound
    func getInterfaces() -> [(name : String, addr: String, mac : String)] {

        var addresses = [(name : String, addr: String, mac : String)]()
        var nameToMac = [ String: String ]()

        // Get list of all interfaces on the local machine:
        var ifaddr : UnsafeMutablePointer<ifaddrs>?
        guard getifaddrs(&ifaddr) == 0 else { return [] }
        guard let firstAddr = ifaddr else { return [] }

        // For each interface ...
        for ptr in sequence(first: firstAddr, next: { $0.pointee.ifa_next }) {
            let flags = Int32(ptr.pointee.ifa_flags)
            if var addr = ptr.pointee.ifa_addr {
                let name = String(cString: ptr.pointee.ifa_name)

                // Check for running IPv4, IPv6 interfaces. Skip the loopback interface.
                if (flags & (IFF_UP|IFF_RUNNING|IFF_LOOPBACK)) == (IFF_UP|IFF_RUNNING) {
                    switch Int32(addr.pointee.sa_family) {
                    case AF_LINK:
                        nameToMac[name] = withUnsafePointer(to: &addr) { unsafeAddr in
                            unsafeAddr.withMemoryRebound(to: sockaddr_dl.self, capacity: 1) { dl in
                                dl.withMemoryRebound(to: Int8.self, capacity: 1) { dll in
                                    let lladdr = UnsafeRawBufferPointer(start: dll + 8 + Int(dl.pointee.sdl_nlen), count: Int(dl.pointee.sdl_alen))

                                    if lladdr.count == 6 {
                                        return lladdr.map { String(format:"%02hhx", $0)}.joined(separator: ":")
                                    } else {
                                        return nil
                                    }
                                }
                            }
                        }

                    case AF_INET, AF_INET6:
                        // Convert interface address to a human readable string:
                        var hostname = [CChar](repeating: 0, count: Int(NI_MAXHOST))
                        if (getnameinfo(addr, socklen_t(addr.pointee.sa_len),
                                        &hostname, socklen_t(hostname.count),
                                        nil, socklen_t(0), NI_NUMERICHOST) == 0) {
                            let address = String(cString: hostname)
                            addresses.append( (name: name, addr: address, mac : "") )
                        }
                    default:
                        break
                    }
                }
            }
        }

        freeifaddrs(ifaddr)

        // Now add the mac address to the tuples:
        for (i, addr) in addresses.enumerated() {
            if let mac = nameToMac[addr.name] {
                addresses[i] = (name: addr.name, addr: addr.addr, mac : mac)
            }
        }

        return addresses
    }
}

Usage is:

debugPrint(Networking.networkInterfaceType)

Or:

switch Networking.networkInterfaceType {
case .Ethernet:
    // do something
    break

case .Wifi:
    // do something else
    break

default:
    break
}

Answer 2

For iOS 12.0+, tvOS 12.0+, macOS 10.14+ and watchOS 5.0+ apps you can use NWPathMonitor to solve the problem that you described in your question. Add this code to your application(_:didFinishLaunchingWithOptions:) implementation (Swift 5.1.3/Xcode 11.3.1):

let pathMonitor = NWPathMonitor()
pathMonitor.pathUpdateHandler = { path in
    if path.status == .satisfied {
        if path.usesInterfaceType(.wifi) {
            print("wifi")
        } else if path.usesInterfaceType(.cellular) {
            print("cellular")
        } else if path.usesInterfaceType(.wiredEthernet) {
            print("wiredEthernet")
        } else if path.usesInterfaceType(.loopback) {
            print("loopback")
        } else if path.usesInterfaceType(.other) {
            print("other")
        }
    } else {
        print("not connected")
    }
}
pathMonitor.start(queue: .global(qos: .background))

And don't forget to add import Network to the top of the file.

Answer 3

You can use Reachability API.

let reachability: Reachability = Reachability.reachabilityForInternetConnection()
(reachability.currentReachabilityStatus().value == ReachableViaWiFi.value) // For WiFi
(reachability.currentReachabilityStatus().value == ReachableViaWWAN.value) // For WWAN
(reachability.currentReachabilityStatus().value == NotReachable.value) // For No Internet