Golang Msg.SetEdns0方法代码示例

// Retrieve the DNSKEY records of a zone and convert them
// to DS records for SHA1, SHA256 and SHA384.
func ExampleDS(zone string) {
	config, _ := dns.ClientConfigFromFile("/etc/resolv.conf")
	c := new(dns.Client)
	m := new(dns.Msg)
	if zone == "" {
		zone = "miek.nl"
	}
	m.SetQuestion(dns.Fqdn(zone), dns.TypeDNSKEY)
	m.SetEdns0(4096, true)
	r, _, err := c.Exchange(m, config.Servers[0]+":"+config.Port)
	if err != nil {
		return
	}
	if r.Rcode != dns.RcodeSuccess {
		return
	}
	for _, k := range r.Answer {
		if key, ok := k.(*dns.DNSKEY); ok {
			for _, alg := range []uint8{dns.SHA1, dns.SHA256, dns.SHA384} {
				fmt.Printf("%s; %d\n", key.ToDS(alg).String(), key.Flags)
			}
		}
	}
}

func serve(w dns.ResponseWriter, req *dns.Msg, z *Zone) {

	qtype := req.Question[0].Qtype

	logPrintf("[zone %s] incoming %s %s %d from %s\n", z.Origin, req.Question[0].Name,
		dns.TypeToString[qtype], req.MsgHdr.Id, w.RemoteAddr())

	// Global meter
	metrics.Get("queries").(metrics.Meter).Mark(1)

	// Zone meter
	z.Metrics.Queries.Mark(1)

	logPrintln("Got request", req)

	label := getQuestionName(z, req)

	z.Metrics.LabelStats.Add(label)

	realIp, _, _ := net.SplitHostPort(w.RemoteAddr().String())

	z.Metrics.ClientStats.Add(realIp)

	var ip net.IP // EDNS or real IP
	var edns *dns.EDNS0_SUBNET
	var opt_rr *dns.OPT

	for _, extra := range req.Extra {

		switch extra.(type) {
		case *dns.OPT:
			for _, o := range extra.(*dns.OPT).Option {
				opt_rr = extra.(*dns.OPT)
				switch e := o.(type) {
				case *dns.EDNS0_NSID:
					// do stuff with e.Nsid
				case *dns.EDNS0_SUBNET:
					z.Metrics.EdnsQueries.Mark(1)
					logPrintln("Got edns", e.Address, e.Family, e.SourceNetmask, e.SourceScope)
					if e.Address != nil {
						edns = e
						ip = e.Address
					}
				}
			}
		}
	}

	if len(ip) == 0 { // no edns subnet
		ip = net.ParseIP(realIp)
	}

	targets, netmask := z.Options.Targeting.GetTargets(ip)

	m := new(dns.Msg)
	m.SetReply(req)
	if e := m.IsEdns0(); e != nil {
		m.SetEdns0(4096, e.Do())
	}
	m.Authoritative = true

	// TODO: set scope to 0 if there are no alternate responses
	if edns != nil {
		if edns.Family != 0 {
			if netmask < 16 {
				netmask = 16
			}
			edns.SourceScope = uint8(netmask)
			m.Extra = append(m.Extra, opt_rr)
		}
	}

	labels, labelQtype := z.findLabels(label, targets, qTypes{dns.TypeMF, dns.TypeCNAME, qtype})
	if labelQtype == 0 {
		labelQtype = qtype
	}

	if labels == nil {

		firstLabel := (strings.Split(label, "."))[0]

		if firstLabel == "_status" {
			if qtype == dns.TypeANY || qtype == dns.TypeTXT {
				m.Answer = statusRR(label + "." + z.Origin + ".")
			} else {
				m.Ns = append(m.Ns, z.SoaRR())
			}
			m.Authoritative = true
			w.WriteMsg(m)
			return
		}

		if firstLabel == "_country" {
			if qtype == dns.TypeANY || qtype == dns.TypeTXT {
				h := dns.RR_Header{Ttl: 1, Class: dns.ClassINET, Rrtype: dns.TypeTXT}
				h.Name = label + "." + z.Origin + "."

				txt := []string{
					w.RemoteAddr().String(),
					ip.String(),
//.........这里部分代码省略.........

func serve(w dns.ResponseWriter, req *dns.Msg, z *Zone) {

	qtype := req.Question[0].Qtype

	logPrintf("[zone %s] incoming  %s %s (id %d) from %s\n", z.Origin, req.Question[0].Name,
		dns.TypeToString[qtype], req.Id, w.RemoteAddr())

	// Global meter
	metrics.Get("queries").(metrics.Meter).Mark(1)

	// Zone meter
	z.Metrics.Queries.Mark(1)

	logPrintln("Got request", req)

	label := getQuestionName(z, req)

	z.Metrics.LabelStats.Add(label)

	// IP that's talking to us (not EDNS CLIENT SUBNET)
	var realIP net.IP

	if addr, ok := w.RemoteAddr().(*net.UDPAddr); ok {
		realIP = make(net.IP, len(addr.IP))
		copy(realIP, addr.IP)
	} else if addr, ok := w.RemoteAddr().(*net.TCPAddr); ok {
		realIP = make(net.IP, len(addr.IP))
		copy(realIP, addr.IP)
	}

	z.Metrics.ClientStats.Add(realIP.String())

	var ip net.IP // EDNS or real IP
	var edns *dns.EDNS0_SUBNET
	var opt_rr *dns.OPT

	for _, extra := range req.Extra {

		switch extra.(type) {
		case *dns.OPT:
			for _, o := range extra.(*dns.OPT).Option {
				opt_rr = extra.(*dns.OPT)
				switch e := o.(type) {
				case *dns.EDNS0_NSID:
					// do stuff with e.Nsid
				case *dns.EDNS0_SUBNET:
					z.Metrics.EdnsQueries.Mark(1)
					logPrintln("Got edns", e.Address, e.Family, e.SourceNetmask, e.SourceScope)
					if e.Address != nil {
						edns = e
						ip = e.Address
					}
				}
			}
		}
	}

	if len(ip) == 0 { // no edns subnet
		ip = realIP
	}

	targets, netmask := z.Options.Targeting.GetTargets(ip)

	m := new(dns.Msg)
	m.SetReply(req)
	if e := m.IsEdns0(); e != nil {
		m.SetEdns0(4096, e.Do())
	}
	m.Authoritative = true

	// TODO: set scope to 0 if there are no alternate responses
	if edns != nil {
		if edns.Family != 0 {
			if netmask < 16 {
				netmask = 16
			}
			edns.SourceScope = uint8(netmask)
			m.Extra = append(m.Extra, opt_rr)
		}
	}

	labels, labelQtype := z.findLabels(label, targets, qTypes{dns.TypeMF, dns.TypeCNAME, qtype})
	if labelQtype == 0 {
		labelQtype = qtype
	}

	if labels == nil {

		permitDebug := !*flagPrivateDebug || (realIP != nil && realIP.IsLoopback())

		firstLabel := (strings.Split(label, "."))[0]

		if permitDebug && firstLabel == "_status" {
			if qtype == dns.TypeANY || qtype == dns.TypeTXT {
				m.Answer = statusRR(label + "." + z.Origin + ".")
			} else {
				m.Ns = append(m.Ns, z.SoaRR())
			}
			m.Authoritative = true
			w.WriteMsg(m)
//.........这里部分代码省略.........