Implementing IXFR

_examples/axfr/axfr.go

@@ -3,20 +3,37 @@ package main
 import (
         "fmt"
         "dns"
+        "flag"
 )
 
+
 func main() {
+        var serial *int = flag.Int("serial", 0, "Perform an IXFR with the given serial")
+
+        flag.Parse()
+
 	res := new(dns.Resolver)
 	res.FromFile("/etc/resolv.conf")
+        res.Servers[0] = "213.154.224.1"
 
         ch := make(chan dns.RR)
 
 	m := new(dns.Msg)
 	m.Question = make([]dns.Question, 1)
-	m.Question[0] = dns.Question{"atoom.net", dns.TypeAXFR, dns.ClassINET}
+        if *serial > 0 {
+	        m.Question[0] = dns.Question{"tjeb.nl.", dns.TypeIXFR, dns.ClassINET}
+                soa := new(dns.RR_SOA)
+                soa.Hdr = dns.RR_Header{"tjeb.nl.", dns.TypeSOA, dns.ClassINET, 14400, 0}
+                soa.Serial = uint32(*serial)
+                m.Ns = make([]dns.RR, 1)
+                m.Ns[0] = soa
+                go res.Ixfr(m, ch)
+        } else {
+	        m.Question[0] = dns.Question{"tjeb.nl.", dns.TypeAXFR, dns.ClassINET}
+                go res.Axfr(m, ch)
+        }
 
-        go res.Axfr(m, ch)
-	for x := range ch {
+        for x := range ch {
                 fmt.Printf("%v\n",x)
         }
 }

resolver.go

@@ -120,6 +120,12 @@ func (res *Resolver) Ixfr(q *Msg, m chan RR) {
 		return
 	}
 
+        const (
+                FIRST = iota
+                SECOND
+                LAST
+        )
+
         defer close(m)
 Server:
 	for i := 0; i < len(res.Servers); i++ {
@@ -129,13 +135,13 @@ Server:
 			err = cerr
 			continue Server
 		}
-		first := true
+		state := FIRST
                 var serial int          // The first serial seen is the current server serial
                 var _ = serial
 
                 defer c.Close()
 		for {
-			if first {
+			if state == FIRST {
 				in, cerr = exchangeTCP(c, sending, res, true)
 			} else {
 				in, err = exchangeTCP(c, sending, res, false)
@@ -153,7 +159,7 @@ Server:
 				return
 			}
 
-			if first {
+			if state == FIRST {
                                 // A single SOA RR signals "no changes"
                                 if len(in.Answer) == 1 && checkSOA(in, true) {
                                         c.Close()
@@ -168,12 +174,20 @@ Server:
                                 // This serial is important
                                 serial = int(in.Answer[0].(*RR_SOA).Serial)
 				sendFromMsg(in, m)
-				first = !first
+				state = SECOND
 			}
 
                         // Now we need to check each message for SOA records, to see what we need to do
-			if !first {
-                                
+			if state != FIRST {
+                                if !checkSOA(in, false) {
+                                        // Soa record not the last one
+                                        sendFromMsg(in, m)
+                                        continue
+                                } else{
+                                        c.Close()
+                                        sendFromMsg(in, m)
+                                        return
+                                }
 			}
 		}
 		panic("not reached")