vcan.c 5.6 KB

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  1. /* vcan.c - Virtual CAN interface
  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. #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  41. #include <linux/ethtool.h>
  42. #include <linux/module.h>
  43. #include <linux/init.h>
  44. #include <linux/netdevice.h>
  45. #include <linux/if_arp.h>
  46. #include <linux/if_ether.h>
  47. #include <linux/can.h>
  48. #include <linux/can/can-ml.h>
  49. #include <linux/can/dev.h>
  50. #include <linux/can/skb.h>
  51. #include <linux/slab.h>
  52. #include <net/rtnetlink.h>
  53. #define DRV_NAME "vcan"
  54. MODULE_DESCRIPTION("virtual CAN interface");
  55. MODULE_LICENSE("Dual BSD/GPL");
  56. MODULE_AUTHOR("Urs Thuermann <[email protected]>");
  57. MODULE_ALIAS_RTNL_LINK(DRV_NAME);
  58. /* CAN test feature:
  59. * Enable the echo on driver level for testing the CAN core echo modes.
  60. * See Documentation/networking/can.rst for details.
  61. */
  62. static bool echo; /* echo testing. Default: 0 (Off) */
  63. module_param(echo, bool, 0444);
  64. MODULE_PARM_DESC(echo, "Echo sent frames (for testing). Default: 0 (Off)");
  65. static void vcan_rx(struct sk_buff *skb, struct net_device *dev)
  66. {
  67. struct net_device_stats *stats = &dev->stats;
  68. stats->rx_packets++;
  69. stats->rx_bytes += can_skb_get_data_len(skb);
  70. skb->pkt_type = PACKET_BROADCAST;
  71. skb->dev = dev;
  72. skb->ip_summed = CHECKSUM_UNNECESSARY;
  73. netif_rx(skb);
  74. }
  75. static netdev_tx_t vcan_tx(struct sk_buff *skb, struct net_device *dev)
  76. {
  77. struct net_device_stats *stats = &dev->stats;
  78. unsigned int len;
  79. int loop;
  80. if (can_dropped_invalid_skb(dev, skb))
  81. return NETDEV_TX_OK;
  82. len = can_skb_get_data_len(skb);
  83. stats->tx_packets++;
  84. stats->tx_bytes += len;
  85. /* set flag whether this packet has to be looped back */
  86. loop = skb->pkt_type == PACKET_LOOPBACK;
  87. skb_tx_timestamp(skb);
  88. if (!echo) {
  89. /* no echo handling available inside this driver */
  90. if (loop) {
  91. /* only count the packets here, because the
  92. * CAN core already did the echo for us
  93. */
  94. stats->rx_packets++;
  95. stats->rx_bytes += len;
  96. }
  97. consume_skb(skb);
  98. return NETDEV_TX_OK;
  99. }
  100. /* perform standard echo handling for CAN network interfaces */
  101. if (loop) {
  102. skb = can_create_echo_skb(skb);
  103. if (!skb)
  104. return NETDEV_TX_OK;
  105. /* receive with packet counting */
  106. vcan_rx(skb, dev);
  107. } else {
  108. /* no looped packets => no counting */
  109. consume_skb(skb);
  110. }
  111. return NETDEV_TX_OK;
  112. }
  113. static int vcan_change_mtu(struct net_device *dev, int new_mtu)
  114. {
  115. /* Do not allow changing the MTU while running */
  116. if (dev->flags & IFF_UP)
  117. return -EBUSY;
  118. if (new_mtu != CAN_MTU && new_mtu != CANFD_MTU &&
  119. !can_is_canxl_dev_mtu(new_mtu))
  120. return -EINVAL;
  121. dev->mtu = new_mtu;
  122. return 0;
  123. }
  124. static const struct net_device_ops vcan_netdev_ops = {
  125. .ndo_start_xmit = vcan_tx,
  126. .ndo_change_mtu = vcan_change_mtu,
  127. };
  128. static const struct ethtool_ops vcan_ethtool_ops = {
  129. .get_ts_info = ethtool_op_get_ts_info,
  130. };
  131. static void vcan_setup(struct net_device *dev)
  132. {
  133. dev->type = ARPHRD_CAN;
  134. dev->mtu = CANFD_MTU;
  135. dev->hard_header_len = 0;
  136. dev->addr_len = 0;
  137. dev->tx_queue_len = 0;
  138. dev->flags = IFF_NOARP;
  139. can_set_ml_priv(dev, netdev_priv(dev));
  140. /* set flags according to driver capabilities */
  141. if (echo)
  142. dev->flags |= IFF_ECHO;
  143. dev->netdev_ops = &vcan_netdev_ops;
  144. dev->ethtool_ops = &vcan_ethtool_ops;
  145. dev->needs_free_netdev = true;
  146. }
  147. static struct rtnl_link_ops vcan_link_ops __read_mostly = {
  148. .kind = DRV_NAME,
  149. .priv_size = sizeof(struct can_ml_priv),
  150. .setup = vcan_setup,
  151. };
  152. static __init int vcan_init_module(void)
  153. {
  154. pr_info("Virtual CAN interface driver\n");
  155. if (echo)
  156. pr_info("enabled echo on driver level.\n");
  157. return rtnl_link_register(&vcan_link_ops);
  158. }
  159. static __exit void vcan_cleanup_module(void)
  160. {
  161. rtnl_link_unregister(&vcan_link_ops);
  162. }
  163. module_init(vcan_init_module);
  164. module_exit(vcan_cleanup_module);