Fix #4395, fix out of order messages and fix forward perspective. (#4396)

Signed-off-by: Frank Riley <fhriley@gmail.com>

plugin/dnstap/handler.go

@@ -5,6 +5,7 @@ import (
 	"time"
 
 	"github.com/coredns/coredns/plugin"
+	"github.com/coredns/coredns/plugin/dnstap/msg"
 
 	tap "github.com/dnstap/golang-dnstap"
 	"github.com/miekg/dns"
@@ -25,6 +26,19 @@ func (h Dnstap) TapMessage(m *tap.Message) {
 	h.io.Dnstap(tap.Dnstap{Type: &t, Message: m})
 }
 
+func (h Dnstap) tapQuery(w dns.ResponseWriter, query *dns.Msg, queryTime time.Time) {
+	q := new(tap.Message)
+	msg.SetQueryTime(q, queryTime)
+	msg.SetQueryAddress(q, w.RemoteAddr())
+
+	if h.IncludeRawMessage {
+		buf, _ := query.Pack()
+		q.QueryMessage = buf
+	}
+	msg.SetType(q, tap.Message_CLIENT_QUERY)
+	h.TapMessage(q)
+}
+
 // 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 := &ResponseWriter{
@@ -34,6 +48,10 @@ func (h Dnstap) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg)
 		queryTime:      time.Now(),
 	}
 
+	// The query tap message should be sent before sending the query to the
+	// forwarder. Otherwise, the tap messages will come out out of order.
+	h.tapQuery(w, r, rw.queryTime)
+
 	return plugin.NextOrFailure(h.Name(), h.Next, ctx, rw, r)
 }