DNS resolve multicast os x

dns_resolve_multicast.swift

var res : __res_9_state = __res_9_state()
res_9_ninit(&res)

var addr: in_addr = in_addr()
inet_aton("224.0.0.251", &addr)
res.nsaddr_list.0.sin_addr = addr
res.nsaddr_list.0.sin_family = sa_family_t(AF_INET)
res.nsaddr_list.0.sin_port = in_port_t(5353).bigEndian
res.nscount = 1


let start = NSDate()
var answer = [CUnsignedChar](count: 1024, repeatedValue: 0)
print("About to query....")
// So this takes a LONG time on first bluetooth connect.  I don't know why. The service is found almost instantly.
// Could try forcing IPV6.  Something to do w/ link local.
let nBytesRead : CInt = res_9_nquery(&res, hosttarget, Int32(ns_c_any.rawValue), Int32(ns_t_a.rawValue), &answer, Int32(answer.count))
print("bytes read: \(nBytesRead)")
var handle: __ns_msg = __ns_msg()
res_9_ns_initparse(answer, nBytesRead, &handle)

// ns_msg_count is defined in nameser.h, but it's a C macro.  Expanding it here:
assert(ns_s_an.rawValue == 1, "ns_s_an constant changed")
let answerCount = handle._counts.1

 if answerCount > 0 {
    var ip = [CChar](count: 256, repeatedValue: 0)
    var rr : __ns_rr = __ns_rr()
    if(res_9_ns_parserr(&handle, ns_s_an, 0, &rr) == 0) {
        // Here we can't use ns_rr_rdata, so expanding the macro in nameser.h
        let v1 : UnsafePointer<u_char> = (rr.rdata + 0)

        // Cast between UnsafePointer<u_char> and UnsafePointer<in_addr>
        let v99 : UnsafePointer<in_addr> = UnsafePointer<in_addr>(v1)
        strcpy(&ip, inet_ntoa(v99.memory))
        print(String.fromCString(ip))
    }
 }
print("Done in \(NSDate().timeIntervalSinceDate(start))")