WIP: middleware/dnstap (#711)

middleware/dnstap add

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,
+	}
+}