From c03a914cec77271ba4a4f218f1f0bd5401b3639a Mon Sep 17 00:00:00 2001
From: Miek Gieben <miek@miek.nl>
Date: Mon, 3 Sep 2012 13:56:43 +0200
Subject: [PATCH] add version.server and version.bind

---
 ex/reflect/reflect.go |  2 ++
 example_test.go       |  2 ++
 server.go             | 44 +++++++++++++++++++++++++++++++++++++++++--
 3 files changed, 46 insertions(+), 2 deletions(-)

diff --git a/ex/reflect/reflect.go b/ex/reflect/reflect.go
index 75e3bb20..f43b8a3b 100644
--- a/ex/reflect/reflect.go
+++ b/ex/reflect/reflect.go
@@ -160,6 +160,8 @@ func main() {
 	dns.HandleFunc(".", handleReflect)
 	dns.HandleFunc("authors.bind.", dns.HandleAuthors)
 	dns.HandleFunc("authors.server.", dns.HandleAuthors)
+	dns.HandleFunc("version.bind.", dns.HandleVersion)
+	dns.HandleFunc("version.server.", dns.HandleVersion)
 	go serve("tcp", name, secret)
 	go serve("udp", name, secret)
 	sig := make(chan os.Signal)
diff --git a/example_test.go b/example_test.go
index a1a2e9c4..82bccaa2 100644
--- a/example_test.go
+++ b/example_test.go
@@ -56,6 +56,8 @@ func ExampleToDs(zone string) {
 // queries.
 func ExampleAuthors() {
 	// ... server setup is out of scope ...
+
+	// Register the handle funcs.
 	HandleFunc("authors.bind.", HandleAuthors)
 	HandleFunc("authors.server.", HandleAuthors)
 
diff --git a/server.go b/server.go
index 9c62b44d..41d21d03 100644
--- a/server.go
+++ b/server.go
@@ -73,6 +73,9 @@ var DefaultServeMux = NewServeMux()
 // Authors is a list of authors that helped create or make Go DNS better.
 var Authors = []string{ "Miek Gieben", "Ask Bjorn Hansen", "Dave Cheney", "Dusty Wilson", "Peter van Dijk"}
 
+// Version holds the current version.
+var Version = "Go DNS"
+
 // The HandlerFunc type is an adapter to allow the use of
 // ordinary functions as DNS handlers.  If f is a function
 // with the appropriate signature, HandlerFunc(f) is a
@@ -95,7 +98,14 @@ func HandleFailed(w ResponseWriter, r *Msg) {
 
 // AuthorHandler returns a HandlerFunc that returns the authors
 // of Go DNS for 'authors.bind' or 'authors.server' queries in the
-// CHAOS Class.
+// CHAOS Class. Note with 
+//
+//	HandleFunc("authors.bind.", HandleAuthors)
+//
+// The handler is registered for all DNS classes, thereby potentially
+// hijacking the authors.bind. zone in the IN class. If you need the
+// authors.bind zone to exist in the IN class, you need to register
+// some other handler, check the class in there and then call HandleAuthors.
 func HandleAuthors(w ResponseWriter, r *Msg) {
 	if len(r.Question) != 1 {
 		HandleFailed(w, r)
@@ -109,7 +119,6 @@ func HandleAuthors(w ResponseWriter, r *Msg) {
 		HandleFailed(w, r)
 		return
 	}
-	// primary author
 	m := new(Msg)
 	m.SetReply(r)
 	for _, author := range Authors {
@@ -119,8 +128,39 @@ func HandleAuthors(w ResponseWriter, r *Msg) {
 	w.Write(m)
 }
 
+// VersionHandler returns a HandlerFunc that returns the version
+// of Go DNS for 'version.bind' or 'version.server' queries in the
+// CHAOS Class. Note with 
+//
+//	HandleFunc("version.bind.", HandleVersion)
+//
+// The handler is registered for all DNS classes, thereby potentially
+// hijacking the version.bind. zone in the IN class. If you need the
+// version.bind zone to exist in the IN class, you need to register
+// some other handler, check the class in there and then call HandleVersion.
+func HandleVersion(w ResponseWriter, r *Msg) {
+	if len(r.Question) != 1 {
+		HandleFailed(w, r)
+		return
+	}
+	if r.Question[0].Qtype != ClassCHAOS && r.Question[0].Qtype != TypeTXT {
+		HandleFailed(w, r)
+		return
+	}
+	if r.Question[0].Name != "version.server." && r.Question[0].Name != "version.bind." {
+		HandleFailed(w, r)
+		return
+	}
+	m := new(Msg)
+	m.SetReply(r)
+	h := RR_Header{r.Question[0].Name, TypeTXT, ClassCHAOS, 0, 0}
+	m.Answer = append(m.Answer, &RR_TXT{h, []string{Version}})
+	w.Write(m)
+}
+
 func authorHandler() Handler { return HandlerFunc(HandleAuthors) }
 func failedHandler() Handler { return HandlerFunc(HandleFailed) }
+func versionHandler() Handler { return HandlerFunc(HandleVersion) }
 
 // Start a server on addresss and network speficied. Invoke handler
 // for any incoming queries.