Big Sur change in getifaddrs()

Question

Created Sep ’20

Replies 3

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Participants 3

The BSD network call:
getifaddrs()
returns an IPV4 address for the WiFi network connection on Catalina and iOS 13, but appears to return only IPV6 addresses on Big Sur and iOS 14.

Is this intended behavior? If so, where is this documented?

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Answer 1

DTS Engineer OP

Apple

Sep ’20

That’s not my experience. How are you testing this?

ps Pasted in below is the code I wrote to digest getifaddrs into something more pleasant. This assumes the SockAddr type I posted here.

Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@apple.com"

Code Block static var allAddresses: [AddressInfo] {
    var addrList: UnsafeMutablePointer<ifaddrs>? = nil
    let err = getifaddrs(&addrList)
    guard err == 0, let start = addrList else { return [] }
    defer { freeifaddrs(start) }
    return sequence(first: start, next: { $0.pointee.ifa_next })
        .map { i -> AddressInfo in
            AddressInfo(
                name: String(cString: i.pointee.ifa_name),
                flags: .init(rawValue: i.pointee.ifa_flags),
                address: i.pointee.ifa_addr.flatMap { SockAddr(saPtr: $0) },
                netmask: i.pointee.ifa_netmask.flatMap { SockAddr(saPtr: $0) },
                destinationAddress: i.pointee.ifa_dstaddr.flatMap { SockAddr(saPtr: $0) },
                data: i.pointee.ifa_data.flatMap { Data(bytes: $0, count: MemoryLayout<if_data>.size) }
            )
        }
}
struct AddressInfo {
    // Reading the (frankly terrifying) code for `getifaddrs` I believe that
    // the name field (`ifa_addr`) is always non-`NULL`.  That seems to be
    // confirmed by the man page.  All the other fields, however, may be
    // NULL.
    var name: String
    var flags: InterfaceFlags
    var address: SockAddr?
    var netmask: SockAddr?
    var destinationAddress: SockAddr?
    var data: Data?
}
struct InterfaceFlags: OptionSet {
    var rawValue: CUnsignedInt
    static let isUp = InterfaceFlags(rawValue: CUnsignedInt(bitPattern: IFF_UP))
    … and so on …
}

0

Answer 2

SuperKingKong OP

Aug ’22

Hello, we used getifaddrs' ifi_ibytes on macOS10 to get traffic data from the utun network card,But the traffic read through ifi_ibytes on macOS11 and macOS12 is doubled. Does the system upgrade affect GetifADdrs? I look forward to your reply. Thanks. SuperJohn

0

Answer 3

DTS Engineer OP

Apple

Aug ’22

Rather than reanimating all the threads that have ever mentioned getifaddrs, please start a new thread with the details of the specific issue you’re dealing with. Feel free to include links to any existing threads if you think they’re relevant. Oh, and tag with with Network so that I see it.

Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

0