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1/* vcan.c - Virtual CAN interface2 *3 * Copyright (c) 2002-2017 Volkswagen Group Electronic Research4 * All rights reserved.5 *6 * Redistribution and use in source and binary forms, with or without7 * modification, are permitted provided that the following conditions8 * are met:9 * 1. Redistributions of source code must retain the above copyright10 * notice, this list of conditions and the following disclaimer.11 * 2. Redistributions in binary form must reproduce the above copyright12 * notice, this list of conditions and the following disclaimer in the13 * documentation and/or other materials provided with the distribution.14 * 3. Neither the name of Volkswagen nor the names of its contributors15 * may be used to endorse or promote products derived from this software16 * without specific prior written permission.17 *18 * Alternatively, provided that this notice is retained in full, this19 * software may be distributed under the terms of the GNU General20 * Public License ("GPL") version 2, in which case the provisions of the21 * GPL apply INSTEAD OF those given above.22 *23 * The provided data structures and external interfaces from this code24 * are not restricted to be used by modules with a GPL compatible license.25 *26 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS27 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT28 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR29 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT30 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,31 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT32 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,33 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY34 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT35 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE36 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH37 * DAMAGE.38 *39 */40 41#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt42 43#include <linux/ethtool.h>44#include <linux/module.h>45#include <linux/init.h>46#include <linux/netdevice.h>47#include <linux/if_arp.h>48#include <linux/if_ether.h>49#include <linux/can.h>50#include <linux/can/can-ml.h>51#include <linux/can/dev.h>52#include <linux/can/skb.h>53#include <linux/slab.h>54#include <net/rtnetlink.h>55 56#define DRV_NAME "vcan"57 58MODULE_DESCRIPTION("virtual CAN interface");59MODULE_LICENSE("Dual BSD/GPL");60MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>");61MODULE_ALIAS_RTNL_LINK(DRV_NAME);62 63/* CAN test feature:64 * Enable the echo on driver level for testing the CAN core echo modes.65 * See Documentation/networking/can.rst for details.66 */67 68static bool echo; /* echo testing. Default: 0 (Off) */69module_param(echo, bool, 0444);70MODULE_PARM_DESC(echo, "Echo sent frames (for testing). Default: 0 (Off)");71 72static void vcan_rx(struct sk_buff *skb, struct net_device *dev)73{74 struct net_device_stats *stats = &dev->stats;75 76 stats->rx_packets++;77 stats->rx_bytes += can_skb_get_data_len(skb);78 79 skb->pkt_type = PACKET_BROADCAST;80 skb->dev = dev;81 skb->ip_summed = CHECKSUM_UNNECESSARY;82 83 netif_rx(skb);84}85 86static netdev_tx_t vcan_tx(struct sk_buff *skb, struct net_device *dev)87{88 struct net_device_stats *stats = &dev->stats;89 unsigned int len;90 int loop;91 92 if (can_dropped_invalid_skb(dev, skb))93 return NETDEV_TX_OK;94 95 len = can_skb_get_data_len(skb);96 stats->tx_packets++;97 stats->tx_bytes += len;98 99 /* set flag whether this packet has to be looped back */100 loop = skb->pkt_type == PACKET_LOOPBACK;101 102 skb_tx_timestamp(skb);103 104 if (!echo) {105 /* no echo handling available inside this driver */106 if (loop) {107 /* only count the packets here, because the108 * CAN core already did the echo for us109 */110 stats->rx_packets++;111 stats->rx_bytes += len;112 }113 consume_skb(skb);114 return NETDEV_TX_OK;115 }116 117 /* perform standard echo handling for CAN network interfaces */118 119 if (loop) {120 skb = can_create_echo_skb(skb);121 if (!skb)122 return NETDEV_TX_OK;123 124 /* receive with packet counting */125 vcan_rx(skb, dev);126 } else {127 /* no looped packets => no counting */128 consume_skb(skb);129 }130 return NETDEV_TX_OK;131}132 133static int vcan_change_mtu(struct net_device *dev, int new_mtu)134{135 /* Do not allow changing the MTU while running */136 if (dev->flags & IFF_UP)137 return -EBUSY;138 139 if (new_mtu != CAN_MTU && new_mtu != CANFD_MTU &&140 !can_is_canxl_dev_mtu(new_mtu))141 return -EINVAL;142 143 WRITE_ONCE(dev->mtu, new_mtu);144 return 0;145}146 147static const struct net_device_ops vcan_netdev_ops = {148 .ndo_start_xmit = vcan_tx,149 .ndo_change_mtu = vcan_change_mtu,150};151 152static const struct ethtool_ops vcan_ethtool_ops = {153 .get_ts_info = ethtool_op_get_ts_info,154};155 156static void vcan_setup(struct net_device *dev)157{158 dev->type = ARPHRD_CAN;159 dev->mtu = CANFD_MTU;160 dev->hard_header_len = 0;161 dev->addr_len = 0;162 dev->tx_queue_len = 0;163 dev->flags = IFF_NOARP;164 can_set_ml_priv(dev, netdev_priv(dev));165 166 /* set flags according to driver capabilities */167 if (echo)168 dev->flags |= IFF_ECHO;169 170 dev->netdev_ops = &vcan_netdev_ops;171 dev->ethtool_ops = &vcan_ethtool_ops;172 dev->needs_free_netdev = true;173}174 175static struct rtnl_link_ops vcan_link_ops __read_mostly = {176 .kind = DRV_NAME,177 .priv_size = sizeof(struct can_ml_priv),178 .setup = vcan_setup,179};180 181static __init int vcan_init_module(void)182{183 pr_info("Virtual CAN interface driver\n");184 185 if (echo)186 pr_info("enabled echo on driver level.\n");187 188 return rtnl_link_register(&vcan_link_ops);189}190 191static __exit void vcan_cleanup_module(void)192{193 rtnl_link_unregister(&vcan_link_ops);194}195 196module_init(vcan_init_module);197module_exit(vcan_cleanup_module);198