1 files changed, 29 insertions, 5 deletions
diff --git a/plugin/dnstap/handler.go b/plugin/dnstap/handler.go
index a4b1acff0..59dbabab2 100644
--- a/plugin/dnstap/handler.go
+++ b/plugin/dnstap/handler.go
@@ -6,6 +6,8 @@ import (
 
 	"github.com/coredns/coredns/plugin"
 	"github.com/coredns/coredns/plugin/dnstap/msg"
+	"github.com/coredns/coredns/plugin/pkg/replacer"
+	"github.com/coredns/coredns/request"
 
 	tap "github.com/dnstap/golang-dnstap"
 	"github.com/miekg/dns"
@@ -15,20 +17,40 @@ import (
 type Dnstap struct {
 	Next plugin.Handler
 	io   tapper
+	repl replacer.Replacer
 
 	// IncludeRawMessage will include the raw DNS message into the dnstap messages if true.
 	IncludeRawMessage bool
 	Identity          []byte
 	Version           []byte
+	ExtraFormat       string
 }
 
-// TapMessage sends the message m to the dnstap interface.
+// TapMessage sends the message m to the dnstap interface, without populating "Extra" field.
 func (h Dnstap) TapMessage(m *tap.Message) {
+	if h.ExtraFormat == "" {
+		h.tapWithExtra(m, nil)
+	} else {
+		h.tapWithExtra(m, []byte(h.ExtraFormat))
+	}
+}
+
+// TapMessageWithMetadata sends the message m to the dnstap interface, with "Extra" field being populated.
+func (h Dnstap) TapMessageWithMetadata(ctx context.Context, m *tap.Message, state request.Request) {
+	if h.ExtraFormat == "" {
+		h.tapWithExtra(m, nil)
+		return
+	}
+	extraStr := h.repl.Replace(ctx, state, nil, h.ExtraFormat)
+	h.tapWithExtra(m, []byte(extraStr))
+}
+
+func (h Dnstap) tapWithExtra(m *tap.Message, extra []byte) {
 	t := tap.Dnstap_MESSAGE
-	h.io.Dnstap(&tap.Dnstap{Type: &t, Message: m, Identity: h.Identity, Version: h.Version})
+	h.io.Dnstap(&tap.Dnstap{Type: &t, Message: m, Identity: h.Identity, Version: h.Version, Extra: extra})
 }
 
-func (h Dnstap) tapQuery(w dns.ResponseWriter, query *dns.Msg, queryTime time.Time) {
+func (h Dnstap) tapQuery(ctx context.Context, w dns.ResponseWriter, query *dns.Msg, queryTime time.Time) {
 	q := new(tap.Message)
 	msg.SetQueryTime(q, queryTime)
 	msg.SetQueryAddress(q, w.RemoteAddr())
@@ -38,7 +60,8 @@ func (h Dnstap) tapQuery(w dns.ResponseWriter, query *dns.Msg, queryTime time.Ti
 		q.QueryMessage = buf
 	}
 	msg.SetType(q, tap.Message_CLIENT_QUERY)
-	h.TapMessage(q)
+	state := request.Request{W: w, Req: query}
+	h.TapMessageWithMetadata(ctx, q, state)
 }
 
 // ServeDNS logs the client query and response to dnstap and passes the dnstap Context.
@@ -47,12 +70,13 @@ func (h Dnstap) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg)
 		ResponseWriter: w,
 		Dnstap:         h,
 		query:          r,
+		ctx:            ctx,
 		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)
+	h.tapQuery(ctx, w, r, rw.queryTime)
 
 	return plugin.NextOrFailure(h.Name(), h.Next, ctx, rw, r)
 }