Swift 3如何解决NetService IP？

Question

我在尝试使用Swift 3编写Bonjour。

这是我的代码，我可以接收到委托。

func netServiceDidResolveAddress(_ sender: NetService) {
 print("netServiceDidResolveAddress service name \(sender.name) of type \(sender.type)," +
                "port \(sender.port), addresses \(sender.addresses)")
}

这是我的结果：

netServiceDidResolveAddress 服务名称为Webber的Mac mini，类型为_myapp._tcp.，端口为5678，地址为可选项([<1002162e c0a80205 00000000 00000000>, <1c1e162e 00000000 fe800000 00000000 00bce7ad 24b4b7e8 08000000>])

c0a80205 是我要查找的IP => 192.168.2.5

而地址是[Data]，苹果公司说

服务的地址。这是一个NSData实例的NSArray，每个实例包含一个单独的sockaddr结构，适用于connect(2)。如果未解析服务的地址或服务尚未解析，则返回一个空的NSArray。

我仍然困惑为什么不能使用Data .bytes？因为苹果公司说：“这是一个NSData实例的NSArray”，但我无法像NSData一样使用它。

那么如何将地址解析为可读的IP字符串呢？

我之前尝试过这样做，但没有得到我期望的结果...

let thedata = NSData(bytes: sender.addresses, length: (sender.addresses?.count)!)
var storage = sockaddr_storage()
thedata.getBytes(&storage, length: sizeof(sockaddr_storage))

if Int32(storage.ss_family) == AF_INET {
    let addr4 = withUnsafePointer(&storage) {UnsafePointer<sockaddr_in>($0).pointee }
    print(inet_ntoa(addr4.sin_addr));
}

任何建议都将有所帮助，谢谢。

- Webber Lai

Answer 1

以下是我在Swift 3中的做法。

func netServiceDidResolveAddress(_ sender: NetService) {
    var hostname = [CChar](repeating: 0, count: Int(NI_MAXHOST))
    guard let data = sender.addresses?.first else { return }
    data.withUnsafeBytes { (pointer:UnsafePointer<sockaddr>) -> Void in
        guard getnameinfo(pointer, socklen_t(data.count), &hostname, socklen_t(hostname.count), nil, 0, NI_NUMERICHOST) == 0 else {
            return
        }
    }
    let ipAddress = String(cString:hostname)
    print(ipAddress)
}

Swift 5

>>

Swift 5

var hostname = [CChar](repeating: 0, count: Int(NI_MAXHOST))
data.withUnsafeBytes { (pointer: UnsafeRawBufferPointer) -> Void in
        let sockaddrPtr = pointer.bindMemory(to: sockaddr.self)
        guard let unsafePtr = sockaddrPtr.baseAddress else { return }
        guard getnameinfo(unsafePtr, socklen_t(data.count), &hostname, socklen_t(hostname.count), nil, 0, NI_NUMERICHOST) == 0 else {
            return
        }
    }
let ipAddress = String(cString:hostname)
print(ipAddress)

- Phil Cole

---

Phil，使用Swift 5时我收到了一个警告：“'withUnsafeBytes'已弃用：请改用withUnsafeBytes <R>（_：（UnsafeRawBufferPointer）throws-> R）rethrows-> R”。你能告诉我如何解决这个问题吗？苹果的文档对我来说太难了。 - KaasCoder

请使用建议的 withUnsafeBytes 方法并使用 baseAddress.assumingMemoryBound(to:) 进行转换。请参见下面的答案。 - Nick Hingston

Answer 2

编辑Phil Coles的答案，得到了适用于Swift 5.0的无警告解决方案：

func netServiceDidResolveAddress(_ sender: NetService) {
        var hostname = [CChar](repeating: 0, count: Int(NI_MAXHOST))
        guard let data = sender.addresses?.first else { return }
        data.withUnsafeBytes { ptr in
            guard let sockaddr_ptr = ptr.baseAddress?.assumingMemoryBound(to: sockaddr.self) else {
                // handle error
                return
            }
            var sockaddr = sockaddr_ptr.pointee
            guard getnameinfo(sockaddr_ptr, socklen_t(sockaddr.sa_len), &hostname, socklen_t(hostname.count), nil, 0, NI_NUMERICHOST) == 0 else {
                return
            }
        }
        let ipAddress = String(cString:hostname)
        print(ipAddress)
    }

- Nick Hingston

Answer 3

好的...这并不是一个聪明的回答，但至少我可以得到可读的IP地址。

只需使用此函数获取IP字符串即可。

let bonjourDevices = [NetService]()

let bonjourDevice = bonjourDevices[0] 

let host = self.getIPV4StringfromAddress(address:bonjourDevice.addresses!)


func getIPV4StringfromAddress(address: [Data] , port : Int ) -> String{

        let data = address.first! as NSData;

        var ip1 = UInt8(0)
        data.getBytes(&ip1, range: NSMakeRange(4, 1))

        var ip2 = UInt8(0)
        data.getBytes(&ip2, range: NSMakeRange(5, 1))

        var ip3 = UInt8(0)
        data.getBytes(&ip3, range: NSMakeRange(6, 1))

        var ip4 = UInt8(0)
        data.getBytes(&ip4, range: NSMakeRange(7, 1))

        let ipStr = String(format: "%d.%d.%d.%d:%d",ip1,ip2,ip3,ip4,port);

        return ipStr;
    }

- Webber Lai

Answer 4

我无法让它与Data一起工作，但是使用NSData，我会这样使用：

extension NSData {
    func castToCPointer<T>() -> T {
        let mem = UnsafeMutablePointer<T>.allocate(capacity: MemoryLayout<T.Type>.size)
        self.getBytes(mem, length: MemoryLayout<T.Type>.size)
         return mem.move()
    }
}

所以我们有了 netServiceDidResolveAddress：

func netServiceDidResolveAddress(_ sender: NetService) {
    if let addresses = sender.addresses, addresses.count > 0 {
        for address in addresses {
            let data = address as NSData

            let inetAddress: sockaddr_in = data.castToCPointer()
            if inetAddress.sin_family == __uint8_t(AF_INET) {
                if let ip = String(cString: inet_ntoa(inetAddress.sin_addr), encoding: .ascii) {
                    // IPv4
                    print(ip)
                }
            } else if inetAddress.sin_family == __uint8_t(AF_INET6) {
                let inetAddress6: sockaddr_in6 = data.castToCPointer()
                let ipStringBuffer = UnsafeMutablePointer<Int8>.allocate(capacity: Int(INET6_ADDRSTRLEN))
                var addr = inetAddress6.sin6_addr

                if let ipString = inet_ntop(Int32(inetAddress6.sin6_family), &addr, ipStringBuffer, __uint32_t(INET6_ADDRSTRLEN)) {
                    if let ip = String(cString: ipString, encoding: .ascii) {
                        // IPv6
                        print(ip)
                    }
                }

                ipStringBuffer.deallocate(capacity: Int(INET6_ADDRSTRLEN))
            }
        }
    }
}

我有以下结果（在显示之前将ip存储在数组中）：

["172.16.10.120", "172.16.8.251", "::", "::82c9:d9a5:2eed:1c87"]

这段代码是受 https://gist.github.com/agrippa1994/d8c66a2ded74fb2dd801 的启发编写的，使用的是Swift 2.3，并进行了适配以支持Swift 3.0。

- Kévin Renella

---

ipStringBuffer.deallocate(capacity: Int(INET6_ADDRSTRLEN)) 已经过时了，请使用 ipStringBuffer.deallocate() 替代。 - KaasCoder