How to get Domain Name of IP address and IP address from Domain Name in Objective C?

Question

I am able to get the current IP address of my device/machine that I am using - by using this question\'s answer.

I have gone through this question. Java allows to ge

Answer 1

I wrote a Swift version of the accepted answer, though I'm not 100% sure of its correctness.

func reverseDNS(ip: String) -> String {
    var results: UnsafeMutablePointer? = nil
    defer {
        if let results = results {
            freeaddrinfo(results)
        }
    }
    let error = getaddrinfo(ip, nil, nil, &results)
    if (error != 0) {
        print("Unable to reverse ip: \(ip)")
        return ip
    }

    for addrinfo in sequence(first: results, next: { $0?.pointee.ai_next }) {
        guard let pointee = addrinfo?.pointee else {
            print("Unable to reverse ip: \(ip)")
            return ip
        }

        let hname = UnsafeMutablePointer.allocate(capacity: Int(NI_MAXHOST))
        defer {
            hname.deallocate()
        }
        let error = getnameinfo(pointee.ai_addr, pointee.ai_addrlen, hname, socklen_t(NI_MAXHOST), nil, 0, 0)
        if (error != 0) {
            continue
        }
        return String(cString: hname)
    }

    return ip
}