1 files changed, 79 insertions, 0 deletions
diff --git a/plugin/dnstap/handler.go b/plugin/dnstap/handler.go
new file mode 100644
index 000000000..b20bb2ad9
--- /dev/null
+++ b/plugin/dnstap/handler.go
@@ -0,0 +1,79 @@
+package dnstap
+
+import (
+	"fmt"
+	"io"
+
+	"github.com/coredns/coredns/plugin"
+	"github.com/coredns/coredns/plugin/dnstap/msg"
+	"github.com/coredns/coredns/plugin/dnstap/taprw"
+
+	tap "github.com/dnstap/golang-dnstap"
+	"github.com/miekg/dns"
+	"golang.org/x/net/context"
+)
+
+// Dnstap is the dnstap handler.
+type Dnstap struct {
+	Next plugin.Handler
+	Out  io.Writer
+	Pack bool
+}
+
+type (
+	// Tapper is implemented by the Context passed by the dnstap handler.
+	Tapper interface {
+		TapMessage(*tap.Message) error
+		TapBuilder() msg.Builder
+	}
+	tapContext struct {
+		context.Context
+		Dnstap
+	}
+)
+
+// TapperFromContext will return a Tapper if the dnstap plugin is enabled.
+func TapperFromContext(ctx context.Context) (t Tapper) {
+	t, _ = ctx.(Tapper)
+	return
+}
+
+func tapMessageTo(w io.Writer, m *tap.Message) error {
+	frame, err := msg.Marshal(m)
+	if err != nil {
+		return fmt.Errorf("marshal: %s", err)
+	}
+	_, err = w.Write(frame)
+	return err
+}
+
+// TapMessage implements Tapper.
+func (h Dnstap) TapMessage(m *tap.Message) error {
+	return tapMessageTo(h.Out, m)
+}
+
+// TapBuilder implements Tapper.
+func (h Dnstap) TapBuilder() msg.Builder {
+	return msg.Builder{Full: h.Pack}
+}
+
+// ServeDNS logs the client query and response to dnstap and passes the dnstap Context.
+func (h Dnstap) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
+	rw := &taprw.ResponseWriter{ResponseWriter: w, Tapper: &h, Query: r}
+	rw.QueryEpoch()
+
+	code, err := plugin.NextOrFailure(h.Name(), h.Next, tapContext{ctx, h}, rw, r)
+	if err != nil {
+		// ignore dnstap errors
+		return code, err
+	}
+
+	if err := rw.DnstapError(); err != nil {
+		return code, plugin.Error("dnstap", err)
+	}
+
+	return code, nil
+}
+
+// Name returns dnstap.
+func (h Dnstap) Name() string { return "dnstap" }