Add native protocol service plugins

plugins/services/mqtt_test.go

@@ -0,0 +1,19 @@
+//go:build plugin_mqtt || !plugin_selective
+
+package services
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestParseMQTTConnack(t *testing.T) {
+	banner, ok := parseMQTTConnack([]byte{0x20, 0x02, 0x00, 0x05})
+	if !ok || !strings.Contains(banner, "not authorized") {
+		t.Fatalf("unexpected mqtt banner: %q ok=%v", banner, ok)
+	}
+
+	if _, ok := parseMQTTConnack([]byte{0x10, 0x02, 0x00, 0x00}); ok {
+		t.Fatal("unexpected match for non-connack packet")
+	}
+}