Add EventReplayAttack

mtglib/events.go

@@ -99,3 +99,16 @@ func (e EventIPBlocklisted) StreamID() string {
 func (e EventIPBlocklisted) Timestamp() time.Time {
 	return e.CreatedAt
 }
+
+type EventReplayAttack struct {
+	CreatedAt time.Time
+	ConnID    string
+}
+
+func (e EventReplayAttack) StreamID() string {
+	return e.ConnID
+}
+
+func (e EventReplayAttack) Timestamp() time.Time {
+	return e.CreatedAt
+}

mtglib/events_test.go

@@ -87,6 +87,16 @@ func (suite *EventsTestSuite) TestEventIPBlocklisted() {
 	suite.WithinDuration(time.Now(), evt.Timestamp(), 10*time.Millisecond)
 }
 
+func (suite *EventsTestSuite) TestEventReplayAttack() {
+	evt := mtglib.EventReplayAttack{
+		CreatedAt: time.Now(),
+		ConnID:    "CONNID",
+	}
+
+	suite.Equal("CONNID", evt.StreamID())
+	suite.WithinDuration(time.Now(), evt.Timestamp(), 10*time.Millisecond)
+}
+
 func TestEvents(t *testing.T) {
 	t.Parallel()
 	suite.Run(t, &EventsTestSuite{})

mtglib/proxy.go

@@ -166,6 +166,10 @@ func (p *Proxy) doFakeTLSHandshake(ctx *streamContext) bool {
 
 	if p.antiReplayCache.SeenBefore(hello.SessionID) {
 		p.logger.Warning("replay attack has been detected!")
+		p.eventStream.Send(p.ctx, EventReplayAttack{
+			CreatedAt: time.Now(),
+			ConnID:    ctx.connID,
+		})
 		p.doDomainFronting(ctx, rewind)
 
 		return false