Support _status txt queries similar to pgeodns

geodns.go

@@ -5,8 +5,14 @@ import (
  "log"
  "os"
  "os/signal"
+ "time"
 )
 
+const VERSION = "2.0"
+
+var timeStarted = time.Now()
+var qCounter uint64 = 0
+
 var (
  listen = flag.String("listen", ":8053", "set the listener address")
  flaglog = flag.Bool("log", false, "be more verbose")
@@ -19,6 +25,8 @@ func main() {
  log.SetFlags(log.Lmicroseconds | log.Lshortfile)
  flag.Parse()
 
+ log.Printf("Starting geodns/%s\n", VERSION)
+
  dirName := "dns"
 
  Zones := make(Zones)

serve.go

@@ -1,9 +1,13 @@
 package main
 
 import (
+ "encoding/json"
  "github.com/miekg/dns"
  "log"
+ "os"
+ "strconv"
  "strings"
+ "time"
 )
 
 func getQuestionName(z *Zone, req *dns.Msg) string {
@@ -21,6 +25,9 @@ func serve(w dns.ResponseWriter, req *dns.Msg, z *Zone) {
  logPrintf("[zone %s] incoming %s %s %d from %s\n", z.Origin, req.Question[0].Name,
  dns.Rr_str[qtype], req.MsgHdr.Id, w.RemoteAddr())
 
+ // is this safe/atomic or does it need to go through a channel?
+ qCounter++
+
  logPrintln("Got request", req)
 
  label := getQuestionName(z, req)
@@ -47,6 +54,14 @@ func serve(w dns.ResponseWriter, req *dns.Msg, z *Zone) {
 
  labels := z.findLabels(label, country, qtype)
  if labels == nil {
+
+ if label == "_status" && (qtype == dns.TypeANY || qtype == dns.TypeTXT) {
+ m.Answer = statusRR(z)
+ m.Authoritative = true
+ w.Write(m)
+ return
+ }
+
  // return NXDOMAIN
  m.SetRcode(req, dns.RcodeNameError)
  m.Authoritative = true
@@ -84,6 +99,31 @@ func serve(w dns.ResponseWriter, req *dns.Msg, z *Zone) {
  return
 }
 
+func statusRR(z *Zone) []dns.RR {
+ var h dns.RR_Header
+ h.Ttl = 1
+ h.Class = dns.ClassINET
+ h.Rrtype = dns.TypeTXT
+ h.Name = "_status." + z.Origin + "."
+ rr := &dns.RR_TXT{Hdr: h}
+
+ status := map[string]string{"v": VERSION, "id": *listen}
+
+ var hostname, err = os.Hostname()
+ if err == nil {
+ status["h"] = hostname
+ }
+ status["up"] = strconv.Itoa(int(time.Since(timeStarted).Seconds()))
+ status["qs"] = strconv.FormatUint(qCounter, 10)
+
+ js, err := json.Marshal(status)
+ //log.Println("status", status, string(js), err)
+ rr.Txt = []string{string(js)}
+ rrs := make([]dns.RR, 1)
+ rrs[0] = rr
+ return rrs
+}
+
 func setupServerFunc(Zone *Zone) func(dns.ResponseWriter, *dns.Msg) {
  return func(w dns.ResponseWriter, r *dns.Msg) {
  serve(w, r, Zone)