debug: выделить link keepalive в отдельную категорию KEEPALIVE (21), добавить DEBUG_DEBUG при приёме keepalive-пакета

lib/debug_config.c

@@ -125,6 +125,8 @@ static const struct {
     {"traffic", DEBUG_CATEGORY_TRAFFIC},
     {"debug", DEBUG_CATEGORY_DEBUG},
     {"general", DEBUG_CATEGORY_GENERAL},
+    {"nat", DEBUG_CATEGORY_NAT},
+    {"keepalive", DEBUG_CATEGORY_KEEPALIVE},
     {"all", DEBUG_CATEGORY_ALL},
     {NULL, DEBUG_CATEGORY_NONE}
 };
@@ -216,6 +218,8 @@ const char* debug_get_category_name(debug_category_t category_idx) {
         case DEBUG_CATEGORY_TRAFFIC:    return "TRAFFIC";
         case DEBUG_CATEGORY_DEBUG:      return "DEBUG";
         case DEBUG_CATEGORY_GENERAL:    return "GENERAL";
+        case DEBUG_CATEGORY_NAT:        return "NAT";
+        case DEBUG_CATEGORY_KEEPALIVE:  return "KEEPALIVE";
         case DEBUG_CATEGORY_NONE:       return "NONE";
         default:                        return "UNKNOWN";
     }