From 35efcee5c932fa9400502bde7208b3676732cee9 Mon Sep 17 00:00:00 2001 From: Gregory Nutt Date: Fri, 15 May 2020 07:06:50 -0600 Subject: [PATCH] net/netdev/netdev_register.c: Add some comments. This commit adds some short comments to explain some perplexing logic of PR #1047. --- net/netdev/netdev_register.c | 46 +++++++++++++----------------------- 1 file changed, 17 insertions(+), 29 deletions(-) diff --git a/net/netdev/netdev_register.c b/net/netdev/netdev_register.c index 15a5d1d834..85483dc230 100644 --- a/net/netdev/netdev_register.c +++ b/net/netdev/netdev_register.c @@ -1,36 +1,20 @@ /**************************************************************************** * net/netdev/netdev_register.c * - * Copyright (C) 2007-2012, 2014-2015, 2017-2018 Gregory Nutt. All rights - * reserved. - * Author: Gregory Nutt + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. The + * ASF licenses this file to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance with the + * License. You may obtain a copy of the License at * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: + * http://www.apache.org/licenses/LICENSE-2.0 * - * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in - * the documentation and/or other materials provided with the - * distribution. - * 3. Neither the name NuttX nor the names of its contributors may be - * used to endorse or promote products derived from this software - * without specific prior written permission. - * - * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS - * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT - * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS - * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE - * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, - * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, - * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS - * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED - * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT - * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN - * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE - * POSSIBILITY OF SUCH DAMAGE. + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT + * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the + * License for the specific language governing permissions and limitations + * under the License. * ****************************************************************************/ @@ -335,7 +319,11 @@ int netdev_register(FAR struct net_driver_s *dev, enum net_lltype_e lltype) return -EINVAL; } - /* Update the package length */ + /* Update the package length. A network driver may provide custom + * values for MAC header length and for the maximum packet size. Some + * driver implementations (for example, the simulator) will require + * dynamic MTU calculations to support tunneling (as an example). + */ if (dev->d_llhdrlen == 0) {