// libresolv continues to the next server when it receives
	// an invalid referral response. See golang.org/issue/15434.
	if rcode == dnsmessage.RCodeSuccess && !h.Authoritative && !h.RecursionAvailable && err == dnsmessage.ErrSectionDone && !hasAdd {
		return errLameReferral
	}

	if rcode != dnsmessage.RCodeSuccess && rcode != dnsmessage.RCodeNameError {
		// None of the error codes make sense
		// for the query we sent. If we didn't get

	var response *dns.Msg
	for _, upstream := range c.resolvConfServers {
		cResponse, _, err := c.Exchange(req, upstream)
		rcode := dns.RcodeServerFailure
		if err == nil && cResponse != nil {
			rcode = cResponse.Rcode
		}
		if rcode == dns.RcodeServerFailure {
			// RcodeServerFailure means the upstream cannot serve the request

						// just make sure that the response has a valid DNS response from upstream resolvers
						if res.Rcode != dns.RcodeSuccess {
							t.Errorf("upstream dns resolution for %s failed: %v", tt.host, res)
						}
					} else {
						if tt.expectResolutionFailure > 0 && tt.expectResolutionFailure != res.Rcode {
							t.Errorf("expected resolution failure does not match with response code for %s: expected: %v, got: %v",

	var ridx Index
	var name string
	var rcode int
	{
		r := pr.TempDecoder(RelocName, idx, SyncObject1)
		r.Sync(SyncSym)
		r.Sync(SyncPkg)
		ridx = r.Reloc(RelocPkg)
		name = r.String()
		rcode = r.Code(SyncCodeObj)
		pr.RetireDecoder(&r)
	}

	path := pr.PeekPkgPath(ridx)
	assert(name != "")

	tag := CodeObj(rcode)

	return path, name, tag

		id := uuid.New()
		log = log.WithLabels("id", id)
	}
	log.Debugf("request %v", req)

	if len(req.Question) == 0 {
		response = new(dns.Msg)
		response.SetReply(req)
		response.Rcode = dns.RcodeServerFailure
		_ = w.WriteMsg(response)
		return
	}

	lp := h.lookupTable.Load()
	hostname := strings.ToLower(req.Question[0].Name)
	if lp == nil {
		if h.respondBeforeSync {

import java.net.InetAddress;

import jcifs.smb1.util.Hexdump;

abstract class NameServicePacket {

    // opcode
    static final int QUERY = 0;
    static final int WACK = 7;

    // rcode
    static final int FMT_ERR = 0x1;
    static final int SRV_ERR = 0x2;
    static final int IMP_ERR = 0x4;
    static final int RFS_ERR = 0x5;
    static final int ACT_ERR = 0x6;
    static final int CFT_ERR = 0x7;

import jcifs.Configuration;
import jcifs.util.Hexdump;


abstract class NameServicePacket {

    // opcode
    static final int QUERY = 0;
    static final int WACK = 7;

    // rcode
    static final int FMT_ERR = 0x1;
    static final int SRV_ERR = 0x2;
    static final int IMP_ERR = 0x4;
    static final int RFS_ERR = 0x5;
    static final int ACT_ERR = 0x6;
    static final int CFT_ERR = 0x7;