Ejemplo n.º 1
0
Archivo: q.go Proyecto: elazarl/godns
func newConnMsg(qname, nameserver string, attempts int, qtype, qclass uint16, aa, ad, cd, rd, dnssec, nsid bool) (*dns.Conn, *dns.Msg) {
	d := new(dns.Conn)
	d.RemoteAddr = nameserver
	d.Attempts = attempts

	m := new(dns.Msg)
	m.MsgHdr.Authoritative = aa
	m.MsgHdr.AuthenticatedData = ad
	m.MsgHdr.CheckingDisabled = cd
	m.MsgHdr.RecursionDesired = rd
	m.Question = make([]dns.Question, 1)
	if dnssec || nsid {
		opt := new(dns.RR_OPT)
		opt.SetDo()
		opt.SetVersion(0)
		opt.SetUDPSize(dns.DefaultMsgSize)
		if nsid {
			opt.SetNsid("")
		}
		m.Extra = make([]dns.RR, 1)
		m.Extra[0] = opt
	}
	m.Question[0] = dns.Question{qname, qtype, qclass}
	m.Id = dns.Id()
	return d, m
}
Ejemplo n.º 2
0
func main() {
	dnssec := flag.Bool("dnssec", false, "request DNSSEC records")
	query := flag.Bool("question", false, "show question")
	short := flag.Bool("short", false, "abbreviate long DNSSEC records")
	check := flag.Bool("check", false, "check internal DNSSEC consistency")
	anchor := flag.String("anchor", "", "use the DNSKEY in this file for checking consistency")
	port := flag.Int("port", 53, "port number to use")
	aa := flag.Bool("aa", false, "set AA flag in query")
	ad := flag.Bool("ad", false, "set AD flag in query")
	cd := flag.Bool("cd", false, "set CD flag in query")
	rd := flag.Bool("rd", true, "unset RD flag in query")
	tcp := flag.Bool("tcp", false, "TCP mode")
	nsid := flag.Bool("nsid", false, "ask for NSID")
	flag.Usage = func() {
		fmt.Fprintf(os.Stderr, "Usage: %s [@server] [qtype] [qclass] [name ...]\n", os.Args[0])
		flag.PrintDefaults()
	}

	conf, _ := dns.ClientConfigFromFile("/etc/resolv.conf")
	nameserver := "@" + conf.Servers[0]
	qtype := uint16(0)
	qclass := uint16(dns.ClassINET) // Default qclass
	var qname []string

	flag.Parse()
	if *anchor != "" {
		f, err := os.Open(*anchor)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Failure to open %s: %s\n", *anchor, err.Error())
		}
		r, err := dns.ReadRR(f, *anchor)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Failure to read an RR from %s: %s\n", *anchor, err.Error())
		}
		if k, ok := r.(*dns.RR_DNSKEY); !ok {
			fmt.Fprintf(os.Stderr, "No DNSKEY read from %s\n", *anchor)
		} else {
			dnskey = k
		}
	}

Flags:
	for i := 0; i < flag.NArg(); i++ {
		// If it starts with @ it is a nameserver
		if flag.Arg(i)[0] == '@' {
			nameserver = flag.Arg(i)
			continue Flags
		}
		// First class, then type, to make ANY queries possible
		// And if it looks like type, it is a type
		if k, ok := dns.Str_rr[strings.ToUpper(flag.Arg(i))]; ok {
			qtype = k
			continue Flags
		}
		// If it looks like a class, it is a class
		if k, ok := dns.Str_class[strings.ToUpper(flag.Arg(i))]; ok {
			qclass = k
			continue Flags
		}
		// If it starts with TYPExxx it is unknown rr
		if strings.HasPrefix(flag.Arg(i), "TYPE") {
			i, e := strconv.Atoi(string([]byte(flag.Arg(i))[4:]))
			if e == nil {
				qtype = uint16(i)
				continue Flags
			}
		}

		// Anything else is a qname
		qname = append(qname, flag.Arg(i))
	}
	if len(qname) == 0 {
		qname = make([]string, 1)
		qname[0] = "."
		qtype = dns.TypeNS
	}
	if qtype == 0 {
		qtype = dns.TypeA
	}

	nameserver = string([]byte(nameserver)[1:]) // chop off @
	nameserver += ":" + strconv.Itoa(*port)

	// ipv6 todo
	// We use the async query handling, just to show how
	// it is to be used.
	dns.HandleQueryFunc(".", q)
	dns.ListenAndQuery(nil, nil)
	c := dns.NewClient()
	if *tcp {
		c.Net = "tcp"
	}

	m := new(dns.Msg)
	m.MsgHdr.Authoritative = *aa
	m.MsgHdr.AuthenticatedData = *ad
	m.MsgHdr.CheckingDisabled = *cd
	m.MsgHdr.RecursionDesired = *rd
	m.Question = make([]dns.Question, 1)
	if *dnssec || *nsid {
		o := new(dns.RR_OPT)
		o.Hdr.Name = "."
		o.Hdr.Rrtype = dns.TypeOPT
		if *dnssec {
			o.SetDo()
			o.SetUDPSize(dns.DefaultMsgSize)
		}
		if *nsid {
			o.SetNsid("")
		}
		m.Extra = append(m.Extra, o)
	}

	for _, v := range qname {
		m.Question[0] = dns.Question{v, qtype, qclass}
		m.Id = dns.Id()
		if *query {
			fmt.Printf("%s\n", m.String())
		}
		c.Do(m, nameserver)
	}

	i := 0
forever:
	for {
		select {
		case r := <-dns.DefaultReplyChan:
			if r.Reply != nil {
				if r.Reply.Rcode == dns.RcodeSuccess {
					if r.Request.Id != r.Reply.Id {
						fmt.Printf("Id mismatch\n")
					}
				}
				if *check {
					sigCheck(r.Reply, nameserver, *tcp)
					nsecCheck(r.Reply)
				}
				if *short {
					r.Reply = shortMsg(r.Reply)
				}

				fmt.Printf("%v", r.Reply)
			}
			i++
			if i == len(qname) {
				break forever
			}
		}
	}
}
Ejemplo n.º 3
0
func main() {
	dnssec := flag.Bool("dnssec", false, "request DNSSEC records")
	query := flag.Bool("question", false, "show question")
	short := flag.Bool("short", false, "abbreviate long DNSSEC records")
	check := flag.Bool("check", false, "check internal DNSSEC consistency")
	six := flag.Bool("6", false, "use IPv6 only")
	four := flag.Bool("4", false, "use IPv4 only")
	anchor := flag.String("anchor", "", "use the DNSKEY in this file for interal DNSSEC consistency")
	tsig := flag.String("tsig", "", "request tsig with key: [hmac:]name:key")
	port := flag.Int("port", 53, "port number to use")
	aa := flag.Bool("aa", false, "set AA flag in query")
	ad := flag.Bool("ad", false, "set AD flag in query")
	cd := flag.Bool("cd", false, "set CD flag in query")
	rd := flag.Bool("rd", true, "set RD flag in query")
	fallback := flag.Bool("fallback", false, "fallback to 4096 bytes bufsize and after that TCP")
	tcp := flag.Bool("tcp", false, "TCP mode")
	nsid := flag.Bool("nsid", false, "ask for NSID")
	flag.Usage = func() {
		fmt.Fprintf(os.Stderr, "Usage: %s [@server] [qtype] [qclass] [name ...]\n", os.Args[0])
		flag.PrintDefaults()
	}

	conf, _ := dns.ClientConfigFromFile("/etc/resolv.conf")
	nameserver := "@" + conf.Servers[0]
	qtype := uint16(0)
	qclass := uint16(dns.ClassINET) // Default qclass
	var qname []string

	flag.Parse()
	if *anchor != "" {
		f, err := os.Open(*anchor)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Failure to open %s: %s\n", *anchor, err.Error())
		}
		r, err := dns.ReadRR(f, *anchor)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Failure to read an RR from %s: %s\n", *anchor, err.Error())
		}
		if k, ok := r.(*dns.RR_DNSKEY); !ok {
			fmt.Fprintf(os.Stderr, "No DNSKEY read from %s\n", *anchor)
		} else {
			dnskey = k
		}
	}

Flags:
	for i := 0; i < flag.NArg(); i++ {
		// If it starts with @ it is a nameserver
		if flag.Arg(i)[0] == '@' {
			nameserver = flag.Arg(i)
			continue Flags
		}
		// First class, then type, to make ANY queries possible
		// And if it looks like type, it is a type
		if k, ok := dns.Str_rr[strings.ToUpper(flag.Arg(i))]; ok {
			qtype = k
			switch qtype {
			case dns.TypeAXFR:
				fmt.Fprintf(os.Stderr, "AXFR not supported\n")
				return
			case dns.TypeIXFR:
				fmt.Fprintf(os.Stderr, "AXFR not supported\n")
				return
			}
			continue Flags
		}
		// If it looks like a class, it is a class
		if k, ok := dns.Str_class[strings.ToUpper(flag.Arg(i))]; ok {
			qclass = k
			continue Flags
		}
		// If it starts with TYPExxx it is unknown rr
		if strings.HasPrefix(flag.Arg(i), "TYPE") {
			i, e := strconv.Atoi(string([]byte(flag.Arg(i))[4:]))
			if e == nil {
				qtype = uint16(i)
				switch qtype {
				case dns.TypeAXFR:
					fmt.Fprintf(os.Stderr, "AXFR not supported\n")
					return
				case dns.TypeIXFR:
					fmt.Fprintf(os.Stderr, "AXFR not supported\n")
					return
				}
				continue Flags
			}
		}

		// Anything else is a qname
		qname = append(qname, flag.Arg(i))
	}
	if len(qname) == 0 {
		qname = make([]string, 1)
		qname[0] = "."
		qtype = dns.TypeNS
	}
	if qtype == 0 {
		qtype = dns.TypeA
	}

	nameserver = string([]byte(nameserver)[1:]) // chop off @
	nameserver += ":" + strconv.Itoa(*port)

	// We use the async query handling, just to show how it is to be used.
	dns.HandleQuery(".", q)
	dns.ListenAndQuery(nil)
	c := new(dns.Client)
	if *tcp {
		c.Net = "tcp"
		if *four {
			c.Net = "tcp4"
		}
		if *six {
			c.Net = "tcp6"
		}
	} else {
		c.Net = "udp"
		if *four {
			c.Net = "udp4"
		}
		if *six {
			c.Net = "udp6"
		}
	}

	m := new(dns.Msg)
	m.MsgHdr.Authoritative = *aa
	m.MsgHdr.AuthenticatedData = *ad
	m.MsgHdr.CheckingDisabled = *cd
	m.MsgHdr.RecursionDesired = *rd
	m.Question = make([]dns.Question, 1)
	if *dnssec || *nsid {
		o := new(dns.RR_OPT)
		o.Hdr.Name = "."
		o.Hdr.Rrtype = dns.TypeOPT
		if *dnssec {
			o.SetDo()
			o.SetUDPSize(dns.DefaultMsgSize)
		}
		if *nsid {
			o.SetNsid("")
		}
		m.Extra = append(m.Extra, o)
	}

	for _, v := range qname {
		m.Question[0] = dns.Question{v, qtype, qclass}
		m.Id = dns.Id()
		if *query {
			fmt.Printf("%s\n", m.String())
		}
		// Add tsig
		if *tsig != "" {
			if algo, name, secret, ok := tsigKeyParse(*tsig); ok {
				m.SetTsig(name, algo, 300, time.Now().Unix())
				c.TsigSecret = map[string]string{name: secret}
			} else {
				fmt.Fprintf(os.Stderr, "tsig key data error\n")
				return
			}
		}
		c.Do(m, nameserver)
	}

	i := 0
forever:
	for {
		select {
		case r := <-c.Reply:
			if r.Reply != nil {
				if r.Reply.Rcode == dns.RcodeSuccess {
					if r.Request.Id != r.Reply.Id {
						fmt.Printf("Id mismatch\n")
					}
				}
				if r.Reply.MsgHdr.Truncated && *fallback {
					if c.Net != "tcp" {
						if !*dnssec {
							fmt.Printf(";; Truncated, trying %d bytes bufsize\n", dns.DefaultMsgSize)
							o := new(dns.RR_OPT)
							o.Hdr.Name = "."
							o.Hdr.Rrtype = dns.TypeOPT
							o.SetUDPSize(dns.DefaultMsgSize)
							m.Extra = append(m.Extra, o)
							*dnssec = true
							c.Do(m, nameserver)
							break
						} else {
							// First EDNS, then TCP
							fmt.Printf(";; Truncated, trying TCP\n")
							c.Net = "tcp"
							c.Do(m, nameserver)
							break
						}
					}
				}
				if r.Reply.MsgHdr.Truncated && !*fallback {
					fmt.Printf(";; Truncated\n")
				}
				if *check {
					sigCheck(r.Reply, nameserver, *tcp)
					nsecCheck(r.Reply)
				}
				if *short {
					r.Reply = shortMsg(r.Reply)
				}

				fmt.Printf("%v", r.Reply)
				fmt.Printf("\n;; query time: %.3d µs, server: %s(%s)\n", r.Rtt/1e3, r.RemoteAddr, r.RemoteAddr.Network())
				// Server maybe
			}
			i++
			if i == len(qname) {
				break forever
			}
		}
	}
}