added

_examples/q/Makefile

@@ -3,6 +3,6 @@
 # license that can be found in the LICENSE file.
 include $(GOROOT)/src/Make.inc
 TARG=q
-GOFILES=q.go
+GOFILES=q.go fp.go
 DEPS=../../
 include $(GOROOT)/src/Make.cmd

_examples/q/fp.go

@@ -0,0 +1,61 @@
+// Package main provides ...
+package main
+
+import (
+	"dns"
+	"strconv"
+	"strings"
+)
+
+// fingerPrint creates a (short) string representation of a dns message.
+// If a bit is set we uppercase the name 'AD' otherwise it's lowercase 'ad'.
+func msgToFingerPrint(m *dns.Msg) string {
+	if m == nil {
+		return "<nil>"
+	}
+	h := m.MsgHdr
+
+	// Use the same order as in Perl's fpdns.
+	// But use more flags.
+	s := dns.Opcode_str[h.Opcode]
+	s += "," + dns.Rcode_str[h.Rcode]
+	s += valueOf(h.Response, ",qr")
+	s += valueOf(h.Authoritative, ",aa")
+	s += valueOf(h.Truncated, ",tc")
+	s += valueOf(h.RecursionDesired, ",rd")
+	s += valueOf(h.AuthenticatedData, ",ad")
+	s += valueOf(h.CheckingDisabled, ",ad")
+	s += valueOf(h.Zero, ",z")
+
+	s += "," + strconv.Itoa(len(m.Question))
+	s += "," + strconv.Itoa(len(m.Answer))
+	s += "," + strconv.Itoa(len(m.Ns))
+	s += "," + strconv.Itoa(len(m.Extra))
+
+	// EDNS0
+	// V0,DO,4096 (all on)
+	// v0,do,0    (all off)
+	for _, r := range m.Extra {
+		if r.Header().Rrtype == dns.TypeOPT {
+                        // version is always 0 - and I cannot set it anyway
+			s += valueOf(r.(*dns.RR_OPT).Do(), ",do")
+			s += "," + strconv.Itoa(int(r.(*dns.RR_OPT).UDPSize()))
+			return s
+		}
+	}
+	s += ",do,0"
+	return s
+}
+
+// Create a dns message from a fingerprint string
+func fingerPrintToProbe(fp string, q dns.Question) *dns.Msg {
+
+	return nil
+}
+
+func valueOf(x bool, w string) string {
+	if x {
+		return strings.ToUpper(w)
+	}
+	return strings.ToLower(w)
+}

_examples/q/q.go

@@ -12,22 +12,23 @@ import (
 func q(w dns.RequestWriter, m *dns.Msg) {
 	w.Send(m)
 	r, err := w.Receive()
-        if err != nil {
-                fmt.Printf("%s\n", err.String())
-        }
+	if err != nil {
+		fmt.Printf("%s\n", err.String())
+	}
 	w.Write(r)
 }
 
 func main() {
-	var dnssec *bool = flag.Bool("dnssec", false, "request DNSSEC records")
-	var query *bool = flag.Bool("question", false, "show question")
-	var short *bool = flag.Bool("short", false, "abbreviate long DNSKEY and RRSIG RRs")
-	var aa *bool = flag.Bool("aa", false, "set AA flag in query")
-	var ad *bool = flag.Bool("ad", false, "set AD flag in query")
-	var cd *bool = flag.Bool("cd", false, "set CD flag in query")
-	var rd *bool = flag.Bool("rd", true, "unset RD flag in query")
-	var tcp *bool = flag.Bool("tcp", false, "TCP mode")
-	var nsid *bool = flag.Bool("nsid", false, "ask for NSID")
+	dnssec := flag.Bool("dnssec", false, "request DNSSEC records")
+	query := flag.Bool("question", false, "show question")
+	short := flag.Bool("short", false, "abbreviate long DNSKEY and RRSIG RRs")
+	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")
+	fp := flag.Bool("fingerprint", false, "enable server detection")
 	flag.Usage = func() {
 		fmt.Fprintf(os.Stderr, "Usage: %s [@server(:port)] [qtype] [qclass] [name ...]\n", os.Args[0])
 		flag.PrintDefaults()
@@ -89,10 +90,10 @@ Flags:
 	if !strings.HasSuffix(nameserver, ":53") {
 		nameserver += ":53"
 	}
-	// ipv6 todo
 
-        // We use the async query handling, just to show how
-        // it is to be used.
+	// 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()
@@ -107,14 +108,14 @@ Flags:
 	m.MsgHdr.RecursionDesired = *rd
 	m.Question = make([]dns.Question, 1)
 	if *dnssec || *nsid {
-                m.SetEdns0(dns.DefaultMsgSize, true)
+		m.SetEdns0(dns.DefaultMsgSize, true)
 	}
 	for _, v := range qname {
 		m.Question[0] = dns.Question{v, qtype, qclass}
 		m.Id = dns.Id()
-                if *query {
-                        fmt.Printf("%s\n", m.String())
-                }
+		if *query {
+			fmt.Printf("%s\n", m.String())
+		}
 		c.Do(m, nameserver)
 	}
 
@@ -124,14 +125,17 @@ forever:
 		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 r.Reply.Rcode == dns.RcodeSuccess {
+					if r.Request.Id != r.Reply.Id {
+						fmt.Printf("Id mismatch\n")
+					}
+				}
 				if *short {
 					r.Reply = shortMsg(r.Reply)
 				}
+                                if *fp {
+                                        fmt.Printf("%s\n", msgToFingerPrint(r.Reply))
+                                }
 				fmt.Printf("%v", r.Reply)
 			}
 			i++