1 files changed, 61 insertions, 0 deletions
diff --git a/middleware/file/xfr.go b/middleware/file/xfr.go
new file mode 100644
index 000000000..297de2fc5
--- /dev/null
+++ b/middleware/file/xfr.go
@@ -0,0 +1,61 @@
+package file
+
+import (
+	"fmt"
+
+	"github.com/miekg/coredns/middleware"
+
+	"github.com/miekg/dns"
+	"golang.org/x/net/context"
+)
+
+type (
+	Xfr struct {
+		*Zone
+	}
+)
+
+// Serve an AXFR (or maybe later an IXFR) as well.
+func (x Xfr) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
+	state := middleware.State{W: w, Req: r}
+	if !x.TransferAllowed(state) {
+		return dns.RcodeServerFailure, nil
+	}
+	if state.QType() != dns.TypeAXFR {
+		return 0, fmt.Errorf("file: xfr called with non xfr type: %d", state.QType())
+	}
+	if state.Proto() == "udp" {
+		return 0, fmt.Errorf("file: xfr called with udp")
+	}
+
+	records := x.All()
+	if len(records) == 0 {
+		return dns.RcodeServerFailure, nil
+	}
+
+	ch := make(chan *dns.Envelope)
+	defer close(ch)
+	tr := new(dns.Transfer)
+	go tr.Out(w, r, ch)
+
+	j, l := 0, 0
+	records = append(records, records[0])
+	for i, r := range records {
+		l += dns.Len(r)
+		if l > transferLength {
+			ch <- &dns.Envelope{RR: records[j:i]}
+			l = 0
+			j = i
+		}
+	}
+	if j < len(records) {
+		ch <- &dns.Envelope{RR: records[j:]}
+	}
+
+	w.Hijack()
+	// w.Close() // Client closes connection
+	return dns.RcodeSuccess, nil
+}
+
+//const transferLength = 10e3 // Start a new envelop after message reaches this size.
+const transferLength = 100 // Start a new envelop after message reaches this size.