3 files changed, 156 insertions, 0 deletions
diff --git a/middleware/dnstap/msg/msg.go b/middleware/dnstap/msg/msg.go
new file mode 100644
index 000000000..97c7ec7cc
--- /dev/null
+++ b/middleware/dnstap/msg/msg.go
@@ -0,0 +1,89 @@
+// Package msg helps to build a dnstap Message.
+package msg
+
+import (
+	"errors"
+	"net"
+	"time"
+
+	"github.com/coredns/coredns/request"
+
+	tap "github.com/dnstap/golang-dnstap"
+	"github.com/miekg/dns"
+)
+
+// Data helps to build a dnstap Message.
+// It can be transformed into the actual Message using this package.
+type Data struct {
+	Type        tap.Message_Type
+	Packed      []byte
+	SocketProto tap.SocketProtocol
+	SocketFam   tap.SocketFamily
+	Address     []byte
+	Port        uint32
+	TimeSec     uint64
+}
+
+func (d *Data) FromRequest(r request.Request) error {
+	switch addr := r.W.RemoteAddr().(type) {
+	case *net.TCPAddr:
+		d.Address = addr.IP
+		d.Port = uint32(addr.Port)
+		d.SocketProto = tap.SocketProtocol_TCP
+	case *net.UDPAddr:
+		d.Address = addr.IP
+		d.Port = uint32(addr.Port)
+		d.SocketProto = tap.SocketProtocol_UDP
+	default:
+		return errors.New("unknown remote address type")
+	}
+
+	if a := net.IP(d.Address); a.To4() != nil {
+		d.SocketFam = tap.SocketFamily_INET
+	} else {
+		d.SocketFam = tap.SocketFamily_INET6
+	}
+
+	return nil
+}
+
+func (d *Data) Pack(m *dns.Msg) error {
+	packed, err := m.Pack()
+	if err != nil {
+		return err
+	}
+	d.Packed = packed
+	return nil
+}
+
+func (d *Data) Epoch() {
+	d.TimeSec = uint64(time.Now().Unix())
+}
+
+// Transform the data into a client response message.
+func (d *Data) ToClientResponse() *tap.Message {
+	d.Type = tap.Message_CLIENT_RESPONSE
+	return &tap.Message{
+		Type:            &d.Type,
+		SocketFamily:    &d.SocketFam,
+		SocketProtocol:  &d.SocketProto,
+		ResponseTimeSec: &d.TimeSec,
+		ResponseMessage: d.Packed,
+		QueryAddress:    d.Address,
+		QueryPort:       &d.Port,
+	}
+}
+
+// Transform the data into a client query message.
+func (d *Data) ToClientQuery() *tap.Message {
+	d.Type = tap.Message_CLIENT_QUERY
+	return &tap.Message{
+		Type:           &d.Type,
+		SocketFamily:   &d.SocketFam,
+		SocketProtocol: &d.SocketProto,
+		QueryTimeSec:   &d.TimeSec,
+		QueryMessage:   d.Packed,
+		QueryAddress:   d.Address,
+		QueryPort:      &d.Port,
+	}
+}
diff --git a/middleware/dnstap/msg/msg_test.go b/middleware/dnstap/msg/msg_test.go
new file mode 100644
index 000000000..6a54a9e8c
--- /dev/null
+++ b/middleware/dnstap/msg/msg_test.go
@@ -0,0 +1,42 @@
+package msg
+
+import (
+	"net"
+	"reflect"
+	"testing"
+
+	"github.com/coredns/coredns/middleware/test"
+	"github.com/coredns/coredns/request"
+
+	tap "github.com/dnstap/golang-dnstap"
+	"github.com/miekg/dns"
+)
+
+func testRequest(t *testing.T, expected Data, r request.Request) {
+	d := Data{}
+	if err := d.FromRequest(r); err != nil {
+		t.Fail()
+		return
+	}
+	if d.SocketProto != expected.SocketProto ||
+		d.SocketFam != expected.SocketFam ||
+		!reflect.DeepEqual(d.Address, expected.Address) ||
+		d.Port != expected.Port {
+		t.Fatalf("expected: %v, have: %v", expected, d)
+		return
+	}
+}
+func TestRequest(t *testing.T) {
+	testRequest(t, Data{
+		SocketProto: tap.SocketProtocol_UDP,
+		SocketFam:   tap.SocketFamily_INET,
+		Address:     net.ParseIP("10.240.0.1"),
+		Port:        40212,
+	}, testingRequest())
+}
+func testingRequest() request.Request {
+	m := new(dns.Msg)
+	m.SetQuestion("example.com.", dns.TypeA)
+	m.SetEdns0(4097, true)
+	return request.Request{W: &test.ResponseWriter{}, Req: m}
+}
diff --git a/middleware/dnstap/msg/wrapper.go b/middleware/dnstap/msg/wrapper.go
new file mode 100644
index 000000000..0cb6a76c0
--- /dev/null
+++ b/middleware/dnstap/msg/wrapper.go
@@ -0,0 +1,25 @@
+package msg
+
+import (
+	"fmt"
+
+	lib "github.com/dnstap/golang-dnstap"
+	"github.com/golang/protobuf/proto"
+)
+
+func wrap(m *lib.Message) *lib.Dnstap {
+	t := lib.Dnstap_MESSAGE
+	return &lib.Dnstap{
+		Type:    &t,
+		Message: m,
+	}
+}
+
+func Marshal(m *lib.Message) (data []byte, err error) {
+	data, err = proto.Marshal(wrap(m))
+	if err != nil {
+		err = fmt.Errorf("proto: %s", err)
+		return
+	}
+	return
+}