David Brazdil | 0f672f6 | 2019-12-10 10:32:29 +0000 | [diff] [blame^] | 1 | /* vcan.c - Virtual CAN interface |
Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 2 | * |
| 3 | * Copyright (c) 2002-2017 Volkswagen Group Electronic Research |
| 4 | * All rights reserved. |
| 5 | * |
| 6 | * Redistribution and use in source and binary forms, with or without |
| 7 | * modification, are permitted provided that the following conditions |
| 8 | * are met: |
| 9 | * 1. Redistributions of source code must retain the above copyright |
| 10 | * notice, this list of conditions and the following disclaimer. |
| 11 | * 2. Redistributions in binary form must reproduce the above copyright |
| 12 | * notice, this list of conditions and the following disclaimer in the |
| 13 | * documentation and/or other materials provided with the distribution. |
| 14 | * 3. Neither the name of Volkswagen nor the names of its contributors |
| 15 | * may be used to endorse or promote products derived from this software |
| 16 | * without specific prior written permission. |
| 17 | * |
| 18 | * Alternatively, provided that this notice is retained in full, this |
| 19 | * software may be distributed under the terms of the GNU General |
| 20 | * Public License ("GPL") version 2, in which case the provisions of the |
| 21 | * GPL apply INSTEAD OF those given above. |
| 22 | * |
| 23 | * The provided data structures and external interfaces from this code |
| 24 | * are not restricted to be used by modules with a GPL compatible license. |
| 25 | * |
| 26 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 27 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 28 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| 29 | * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| 30 | * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| 31 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| 32 | * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 33 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 34 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 35 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| 36 | * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH |
| 37 | * DAMAGE. |
| 38 | * |
| 39 | */ |
| 40 | |
David Brazdil | 0f672f6 | 2019-12-10 10:32:29 +0000 | [diff] [blame^] | 41 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 42 | |
Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 43 | #include <linux/module.h> |
| 44 | #include <linux/init.h> |
| 45 | #include <linux/netdevice.h> |
| 46 | #include <linux/if_arp.h> |
| 47 | #include <linux/if_ether.h> |
| 48 | #include <linux/can.h> |
David Brazdil | 0f672f6 | 2019-12-10 10:32:29 +0000 | [diff] [blame^] | 49 | #include <linux/can/can-ml.h> |
Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 50 | #include <linux/can/dev.h> |
| 51 | #include <linux/can/skb.h> |
| 52 | #include <linux/slab.h> |
| 53 | #include <net/rtnetlink.h> |
| 54 | |
| 55 | #define DRV_NAME "vcan" |
| 56 | |
| 57 | MODULE_DESCRIPTION("virtual CAN interface"); |
| 58 | MODULE_LICENSE("Dual BSD/GPL"); |
| 59 | MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>"); |
| 60 | MODULE_ALIAS_RTNL_LINK(DRV_NAME); |
| 61 | |
David Brazdil | 0f672f6 | 2019-12-10 10:32:29 +0000 | [diff] [blame^] | 62 | /* CAN test feature: |
Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 63 | * Enable the echo on driver level for testing the CAN core echo modes. |
| 64 | * See Documentation/networking/can.rst for details. |
| 65 | */ |
| 66 | |
| 67 | static bool echo; /* echo testing. Default: 0 (Off) */ |
| 68 | module_param(echo, bool, 0444); |
| 69 | MODULE_PARM_DESC(echo, "Echo sent frames (for testing). Default: 0 (Off)"); |
| 70 | |
Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 71 | static void vcan_rx(struct sk_buff *skb, struct net_device *dev) |
| 72 | { |
| 73 | struct canfd_frame *cfd = (struct canfd_frame *)skb->data; |
| 74 | struct net_device_stats *stats = &dev->stats; |
| 75 | |
| 76 | stats->rx_packets++; |
| 77 | stats->rx_bytes += cfd->len; |
| 78 | |
| 79 | skb->pkt_type = PACKET_BROADCAST; |
| 80 | skb->dev = dev; |
| 81 | skb->ip_summed = CHECKSUM_UNNECESSARY; |
| 82 | |
| 83 | netif_rx_ni(skb); |
| 84 | } |
| 85 | |
| 86 | static netdev_tx_t vcan_tx(struct sk_buff *skb, struct net_device *dev) |
| 87 | { |
| 88 | struct canfd_frame *cfd = (struct canfd_frame *)skb->data; |
| 89 | struct net_device_stats *stats = &dev->stats; |
| 90 | int loop; |
| 91 | |
| 92 | if (can_dropped_invalid_skb(dev, skb)) |
| 93 | return NETDEV_TX_OK; |
| 94 | |
| 95 | stats->tx_packets++; |
| 96 | stats->tx_bytes += cfd->len; |
| 97 | |
| 98 | /* set flag whether this packet has to be looped back */ |
| 99 | loop = skb->pkt_type == PACKET_LOOPBACK; |
| 100 | |
| 101 | if (!echo) { |
| 102 | /* no echo handling available inside this driver */ |
Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 103 | if (loop) { |
David Brazdil | 0f672f6 | 2019-12-10 10:32:29 +0000 | [diff] [blame^] | 104 | /* only count the packets here, because the |
Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 105 | * CAN core already did the echo for us |
| 106 | */ |
| 107 | stats->rx_packets++; |
| 108 | stats->rx_bytes += cfd->len; |
| 109 | } |
| 110 | consume_skb(skb); |
| 111 | return NETDEV_TX_OK; |
| 112 | } |
| 113 | |
| 114 | /* perform standard echo handling for CAN network interfaces */ |
| 115 | |
| 116 | if (loop) { |
Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 117 | skb = can_create_echo_skb(skb); |
| 118 | if (!skb) |
| 119 | return NETDEV_TX_OK; |
| 120 | |
| 121 | /* receive with packet counting */ |
| 122 | vcan_rx(skb, dev); |
| 123 | } else { |
| 124 | /* no looped packets => no counting */ |
| 125 | consume_skb(skb); |
| 126 | } |
| 127 | return NETDEV_TX_OK; |
| 128 | } |
| 129 | |
| 130 | static int vcan_change_mtu(struct net_device *dev, int new_mtu) |
| 131 | { |
| 132 | /* Do not allow changing the MTU while running */ |
| 133 | if (dev->flags & IFF_UP) |
| 134 | return -EBUSY; |
| 135 | |
| 136 | if (new_mtu != CAN_MTU && new_mtu != CANFD_MTU) |
| 137 | return -EINVAL; |
| 138 | |
| 139 | dev->mtu = new_mtu; |
| 140 | return 0; |
| 141 | } |
| 142 | |
| 143 | static const struct net_device_ops vcan_netdev_ops = { |
| 144 | .ndo_start_xmit = vcan_tx, |
| 145 | .ndo_change_mtu = vcan_change_mtu, |
| 146 | }; |
| 147 | |
| 148 | static void vcan_setup(struct net_device *dev) |
| 149 | { |
| 150 | dev->type = ARPHRD_CAN; |
| 151 | dev->mtu = CANFD_MTU; |
| 152 | dev->hard_header_len = 0; |
| 153 | dev->addr_len = 0; |
| 154 | dev->tx_queue_len = 0; |
| 155 | dev->flags = IFF_NOARP; |
David Brazdil | 0f672f6 | 2019-12-10 10:32:29 +0000 | [diff] [blame^] | 156 | dev->ml_priv = netdev_priv(dev); |
Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 157 | |
| 158 | /* set flags according to driver capabilities */ |
| 159 | if (echo) |
| 160 | dev->flags |= IFF_ECHO; |
| 161 | |
| 162 | dev->netdev_ops = &vcan_netdev_ops; |
| 163 | dev->needs_free_netdev = true; |
| 164 | } |
| 165 | |
| 166 | static struct rtnl_link_ops vcan_link_ops __read_mostly = { |
David Brazdil | 0f672f6 | 2019-12-10 10:32:29 +0000 | [diff] [blame^] | 167 | .kind = DRV_NAME, |
| 168 | .priv_size = sizeof(struct can_ml_priv), |
| 169 | .setup = vcan_setup, |
Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 170 | }; |
| 171 | |
| 172 | static __init int vcan_init_module(void) |
| 173 | { |
David Brazdil | 0f672f6 | 2019-12-10 10:32:29 +0000 | [diff] [blame^] | 174 | pr_info("Virtual CAN interface driver\n"); |
Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 175 | |
| 176 | if (echo) |
David Brazdil | 0f672f6 | 2019-12-10 10:32:29 +0000 | [diff] [blame^] | 177 | pr_info("enabled echo on driver level.\n"); |
Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 178 | |
| 179 | return rtnl_link_register(&vcan_link_ops); |
| 180 | } |
| 181 | |
| 182 | static __exit void vcan_cleanup_module(void) |
| 183 | { |
| 184 | rtnl_link_unregister(&vcan_link_ops); |
| 185 | } |
| 186 | |
| 187 | module_init(vcan_init_module); |
| 188 | module_exit(vcan_cleanup_module); |