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- /* vcan.c - Virtual CAN interface
- *
- * Copyright (c) 2002-2017 Volkswagen Group Electronic Research
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 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 of Volkswagen nor the names of its contributors
- * may be used to endorse or promote products derived from this software
- * without specific prior written permission.
- *
- * Alternatively, provided that this notice is retained in full, this
- * software may be distributed under the terms of the GNU General
- * Public License ("GPL") version 2, in which case the provisions of the
- * GPL apply INSTEAD OF those given above.
- *
- * The provided data structures and external interfaces from this code
- * are not restricted to be used by modules with a GPL compatible license.
- *
- * 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.
- *
- */
- #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
- #include <linux/module.h>
- #include <linux/init.h>
- #include <linux/netdevice.h>
- #include <linux/if_arp.h>
- #include <linux/if_ether.h>
- #include <linux/can.h>
- #include <linux/can/can-ml.h>
- #include <linux/can/dev.h>
- #include <linux/can/skb.h>
- #include <linux/slab.h>
- #include <net/rtnetlink.h>
- #define DRV_NAME "vcan"
- MODULE_DESCRIPTION("virtual CAN interface");
- MODULE_LICENSE("Dual BSD/GPL");
- MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>");
- MODULE_ALIAS_RTNL_LINK(DRV_NAME);
- /* CAN test feature:
- * Enable the echo on driver level for testing the CAN core echo modes.
- * See Documentation/networking/can.rst for details.
- */
- static bool echo; /* echo testing. Default: 0 (Off) */
- module_param(echo, bool, 0444);
- MODULE_PARM_DESC(echo, "Echo sent frames (for testing). Default: 0 (Off)");
- static void vcan_rx(struct sk_buff *skb, struct net_device *dev)
- {
- struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
- struct net_device_stats *stats = &dev->stats;
- stats->rx_packets++;
- stats->rx_bytes += cfd->len;
- skb->pkt_type = PACKET_BROADCAST;
- skb->dev = dev;
- skb->ip_summed = CHECKSUM_UNNECESSARY;
- netif_rx_ni(skb);
- }
- static netdev_tx_t vcan_tx(struct sk_buff *skb, struct net_device *dev)
- {
- struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
- struct net_device_stats *stats = &dev->stats;
- int loop;
- if (can_dropped_invalid_skb(dev, skb))
- return NETDEV_TX_OK;
- stats->tx_packets++;
- stats->tx_bytes += cfd->len;
- /* set flag whether this packet has to be looped back */
- loop = skb->pkt_type == PACKET_LOOPBACK;
- if (!echo) {
- /* no echo handling available inside this driver */
- if (loop) {
- /* only count the packets here, because the
- * CAN core already did the echo for us
- */
- stats->rx_packets++;
- stats->rx_bytes += cfd->len;
- }
- consume_skb(skb);
- return NETDEV_TX_OK;
- }
- /* perform standard echo handling for CAN network interfaces */
- if (loop) {
- skb = can_create_echo_skb(skb);
- if (!skb)
- return NETDEV_TX_OK;
- /* receive with packet counting */
- vcan_rx(skb, dev);
- } else {
- /* no looped packets => no counting */
- consume_skb(skb);
- }
- return NETDEV_TX_OK;
- }
- static int vcan_change_mtu(struct net_device *dev, int new_mtu)
- {
- /* Do not allow changing the MTU while running */
- if (dev->flags & IFF_UP)
- return -EBUSY;
- if (new_mtu != CAN_MTU && new_mtu != CANFD_MTU)
- return -EINVAL;
- dev->mtu = new_mtu;
- return 0;
- }
- static const struct net_device_ops vcan_netdev_ops = {
- .ndo_start_xmit = vcan_tx,
- .ndo_change_mtu = vcan_change_mtu,
- };
- static void vcan_setup(struct net_device *dev)
- {
- dev->type = ARPHRD_CAN;
- dev->mtu = CANFD_MTU;
- dev->hard_header_len = 0;
- dev->addr_len = 0;
- dev->tx_queue_len = 0;
- dev->flags = IFF_NOARP;
- can_set_ml_priv(dev, netdev_priv(dev));
- /* set flags according to driver capabilities */
- if (echo)
- dev->flags |= IFF_ECHO;
- dev->netdev_ops = &vcan_netdev_ops;
- dev->needs_free_netdev = true;
- }
- static struct rtnl_link_ops vcan_link_ops __read_mostly = {
- .kind = DRV_NAME,
- .priv_size = sizeof(struct can_ml_priv),
- .setup = vcan_setup,
- };
- static __init int vcan_init_module(void)
- {
- pr_info("Virtual CAN interface driver\n");
- if (echo)
- pr_info("enabled echo on driver level.\n");
- return rtnl_link_register(&vcan_link_ops);
- }
- static __exit void vcan_cleanup_module(void)
- {
- rtnl_link_unregister(&vcan_link_ops);
- }
- module_init(vcan_init_module);
- module_exit(vcan_cleanup_module);
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