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189 lines
5.4 KiB
189 lines
5.4 KiB
/* vcan.c - Virtual CAN interface |
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* |
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* Copyright (c) 2002-2017 Volkswagen Group Electronic Research |
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* All rights reserved. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in the |
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* documentation and/or other materials provided with the distribution. |
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* 3. Neither the name of Volkswagen nor the names of its contributors |
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* may be used to endorse or promote products derived from this software |
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* without specific prior written permission. |
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* |
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* Alternatively, provided that this notice is retained in full, this |
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* software may be distributed under the terms of the GNU General |
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* Public License ("GPL") version 2, in which case the provisions of the |
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* GPL apply INSTEAD OF those given above. |
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* |
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* The provided data structures and external interfaces from this code |
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* are not restricted to be used by modules with a GPL compatible license. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH |
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* DAMAGE. |
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* |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/module.h> |
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#include <linux/init.h> |
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#include <linux/netdevice.h> |
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#include <linux/if_arp.h> |
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#include <linux/if_ether.h> |
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#include <linux/can.h> |
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#include <linux/can/can-ml.h> |
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#include <linux/can/dev.h> |
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#include <linux/can/skb.h> |
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#include <linux/slab.h> |
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#include <net/rtnetlink.h> |
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#define DRV_NAME "vcan" |
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MODULE_DESCRIPTION("virtual CAN interface"); |
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MODULE_LICENSE("Dual BSD/GPL"); |
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MODULE_AUTHOR("Urs Thuermann <[email protected]>"); |
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MODULE_ALIAS_RTNL_LINK(DRV_NAME); |
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/* CAN test feature: |
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* Enable the echo on driver level for testing the CAN core echo modes. |
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* See Documentation/networking/can.rst for details. |
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*/ |
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static bool echo; /* echo testing. Default: 0 (Off) */ |
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module_param(echo, bool, 0444); |
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MODULE_PARM_DESC(echo, "Echo sent frames (for testing). Default: 0 (Off)"); |
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static void vcan_rx(struct sk_buff *skb, struct net_device *dev) |
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{ |
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struct canfd_frame *cfd = (struct canfd_frame *)skb->data; |
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struct net_device_stats *stats = &dev->stats; |
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stats->rx_packets++; |
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stats->rx_bytes += cfd->len; |
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skb->pkt_type = PACKET_BROADCAST; |
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skb->dev = dev; |
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skb->ip_summed = CHECKSUM_UNNECESSARY; |
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netif_rx_ni(skb); |
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} |
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static netdev_tx_t vcan_tx(struct sk_buff *skb, struct net_device *dev) |
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{ |
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struct canfd_frame *cfd = (struct canfd_frame *)skb->data; |
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struct net_device_stats *stats = &dev->stats; |
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int loop, len; |
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if (can_dropped_invalid_skb(dev, skb)) |
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return NETDEV_TX_OK; |
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len = cfd->can_id & CAN_RTR_FLAG ? 0 : cfd->len; |
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stats->tx_packets++; |
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stats->tx_bytes += len; |
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/* set flag whether this packet has to be looped back */ |
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loop = skb->pkt_type == PACKET_LOOPBACK; |
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if (!echo) { |
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/* no echo handling available inside this driver */ |
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if (loop) { |
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/* only count the packets here, because the |
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* CAN core already did the echo for us |
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*/ |
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stats->rx_packets++; |
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stats->rx_bytes += len; |
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} |
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consume_skb(skb); |
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return NETDEV_TX_OK; |
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} |
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/* perform standard echo handling for CAN network interfaces */ |
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if (loop) { |
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skb = can_create_echo_skb(skb); |
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if (!skb) |
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return NETDEV_TX_OK; |
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/* receive with packet counting */ |
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vcan_rx(skb, dev); |
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} else { |
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/* no looped packets => no counting */ |
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consume_skb(skb); |
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} |
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return NETDEV_TX_OK; |
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} |
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static int vcan_change_mtu(struct net_device *dev, int new_mtu) |
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{ |
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/* Do not allow changing the MTU while running */ |
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if (dev->flags & IFF_UP) |
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return -EBUSY; |
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if (new_mtu != CAN_MTU && new_mtu != CANFD_MTU) |
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return -EINVAL; |
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dev->mtu = new_mtu; |
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return 0; |
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} |
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static const struct net_device_ops vcan_netdev_ops = { |
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.ndo_start_xmit = vcan_tx, |
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.ndo_change_mtu = vcan_change_mtu, |
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}; |
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static void vcan_setup(struct net_device *dev) |
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{ |
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dev->type = ARPHRD_CAN; |
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dev->mtu = CANFD_MTU; |
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dev->hard_header_len = 0; |
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dev->addr_len = 0; |
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dev->tx_queue_len = 0; |
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dev->flags = IFF_NOARP; |
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can_set_ml_priv(dev, netdev_priv(dev)); |
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/* set flags according to driver capabilities */ |
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if (echo) |
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dev->flags |= IFF_ECHO; |
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dev->netdev_ops = &vcan_netdev_ops; |
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dev->needs_free_netdev = true; |
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} |
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static struct rtnl_link_ops vcan_link_ops __read_mostly = { |
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.kind = DRV_NAME, |
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.priv_size = sizeof(struct can_ml_priv), |
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.setup = vcan_setup, |
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}; |
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static __init int vcan_init_module(void) |
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{ |
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pr_info("Virtual CAN interface driver\n"); |
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if (echo) |
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pr_info("enabled echo on driver level.\n"); |
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return rtnl_link_register(&vcan_link_ops); |
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} |
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static __exit void vcan_cleanup_module(void) |
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{ |
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rtnl_link_unregister(&vcan_link_ops); |
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} |
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module_init(vcan_init_module); |
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module_exit(vcan_cleanup_module);
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