split off the questions

_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 fp.go lex.go
+GOFILES=q.go fp.go lex.go dns.go
 DEPS=../../
 include $(GOROOT)/src/Make.cmd

_examples/q/dns.go

@@ -0,0 +1,36 @@
+package main
+
+import (
+	"dns"
+)
+
+// Check if the server responds at all
+func dnsAlive(l *lexer) stateFn {
+	l.verbose("Alive")
+	l.setString("QUERY,NOERROR,qr,aa,tc,rd,ra,ad,cd,z,1,0,0,0,do,0")
+	l.setQuestion(".", dns.TypeNS, dns.ClassINET)
+
+	f := l.probe()
+
+	if f.ok() {
+		return dnsDoBitMirror
+	}
+	l.emit(&item{itemError, f.error()})
+	return nil
+}
+
+// Check if the server returns the DO-bit when set in the request.                                                                          
+func dnsDoBitMirror(l *lexer) stateFn {
+	l.verbose("DoBitMirror")
+	// The important part here is that the DO bit is on in the reply
+	l.setString("QUERY,NOERROR,qr,aa,tc,RD,ra,ad,cd,z,1,0,0,0,DO,0")
+	l.setQuestion(".", dns.TypeNS, dns.ClassINET)
+
+	f := l.probe()
+	if !f.Do {
+		l.emit(&item{itemSoftware, NSD})
+		return nil
+	}
+	l.emit(&item{itemSoftware, BIND})
+	return nil
+}

_examples/q/fp.go

@@ -27,6 +27,7 @@ func startParse(addr string) {
 		fp:     new(fingerprint),
 		items:  make(chan item),
 		state:  dnsAlive,
+		debug:  true,
 	}
 
 	l.run()
@@ -61,6 +62,7 @@ type fingerprint struct {
 	Authoritative      bool
 	Truncated          bool
 	RecursionDesired   bool
+	RecursionAvailable bool
 	AuthenticatedData  bool
 	CheckingDisabled   bool
 	Zero               bool
@@ -86,6 +88,7 @@ func (f *fingerprint) String() string {
 	s += valueOfBool(f.Authoritative, ",aa")
 	s += valueOfBool(f.Truncated, ",tc")
 	s += valueOfBool(f.RecursionDesired, ",rd")
+	s += valueOfBool(f.RecursionAvailable, ",ra")
 	s += valueOfBool(f.AuthenticatedData, ",ad")
 	s += valueOfBool(f.CheckingDisabled, ",cd")
 	s += valueOfBool(f.Zero, ",z")
@@ -129,28 +132,33 @@ func (f *fingerprint) setString(str string) {
 				f.RecursionDesired = true
 			}
 		case 6:
+			f.RecursionAvailable = false
+			if s == strings.ToUpper("ra") {
+				f.RecursionAvailable = true
+			}
+		case 7:
 			f.AuthenticatedData = false
 			if s == strings.ToUpper("ad") {
 				f.AuthenticatedData = true
 			}
-		case 7:
+		case 8:
 			f.CheckingDisabled = false
 			if s == strings.ToUpper("cd") {
 				f.CheckingDisabled = true
 			}
-		case 8:
+		case 9:
 			f.Zero = false
 			if s == strings.ToUpper("z") {
 				f.Zero = true
 			}
-		case 9, 10, 11, 12:
+		case 10, 11, 12, 13:
 			// Can not set content of the message
-		case 13:
+		case 14:
 			f.Do = false
 			if s == strings.ToUpper("do") {
 				f.Do = true
 			}
-		case 14:
+		case 15:
 			f.UDPSize = 0
 			f.UDPSize = valueOfString(s)
 		default:
@@ -190,6 +198,7 @@ func msgToFingerprint(m *dns.Msg) *fingerprint {
 	f.Authoritative = h.Authoritative
 	f.Truncated = h.Truncated
 	f.RecursionDesired = h.RecursionDesired
+	f.RecursionAvailable = h.RecursionAvailable
 	f.AuthenticatedData = h.AuthenticatedData
 	f.CheckingDisabled = h.CheckingDisabled
 	f.Zero = h.Zero

_examples/q/lex.go

@@ -34,10 +34,15 @@ type lexer struct {
 	q      dns.Question // question to ask.
 	items  chan item    // channel of scanned items.
 	state  stateFn      // the next function to enter.
+	debug  bool         // if true, the fingerprints are printed.
 }
 
 func (l *lexer) probe() *fingerprint {
-	return sendProbe(l.client, l.addr, l.fp, l.q)
+	f := sendProbe(l.client, l.addr, l.fp, l.q)
+	if l.debug {
+		fmt.Printf("  QR fp: %s\n", f)
+	}
+	return f
 }
 
 func (l *lexer) emit(i *item) {
@@ -46,6 +51,9 @@ func (l *lexer) emit(i *item) {
 
 func (l *lexer) setString(s string) {
 	l.fp.setString(s)
+	if l.debug {
+		fmt.Printf("   Q fp: %s\n", s)
+	}
 }
 
 func (l *lexer) setQuestion(name string, t uint16, c uint16) {
@@ -64,36 +72,3 @@ func (l *lexer) run() {
 func (l *lexer) verbose(s string) {
 	fmt.Printf("running: dns%s\n", s)
 }
-
-// "Lexer" functions, prefixed with dns
-
-// Check if the server responds at all
-func dnsAlive(l *lexer) stateFn {
-	l.verbose("Alive")
-	l.setString("QUERY,NOERROR,qr,aa,tc,rd,ad,cd,z,1,0,0,0,do,0")
-	l.setQuestion(".", dns.TypeNS, dns.ClassINET)
-
-	f := l.probe()
-
-	if f.ok() {
-		return dnsDoBitMirror
-	}
-	l.emit(&item{itemError, f.error()})
-	return nil
-}
-
-// Check if the server returns the DO-bit when set in the request. 
-func dnsDoBitMirror(l *lexer) stateFn {
-	l.verbose("DoBitMirror")
-	// The important part here is that the DO bit is on in the reply
-	l.setString("QUERY,NOERROR,qr,aa,tc,RD,ad,cd,z,1,0,0,0,DO,0")
-	l.setQuestion(".", dns.TypeNS, dns.ClassINET)
-
-	f := l.probe()
-	if !f.Do {
-		l.emit(&item{itemSoftware, NSD})
-                return nil
-	}
-	l.emit(&item{itemSoftware, BIND})
-	return nil
-}