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Oliver Hartkoppccb29632007-11-16 15:56:08 -08001/*
2 * vcan.c - Virtual CAN interface
3 *
4 * Copyright (c) 2002-2007 Volkswagen Group Electronic Research
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of Volkswagen nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * Alternatively, provided that this notice is retained in full, this
20 * software may be distributed under the terms of the GNU General
21 * Public License ("GPL") version 2, in which case the provisions of the
22 * GPL apply INSTEAD OF those given above.
23 *
24 * The provided data structures and external interfaces from this code
25 * are not restricted to be used by modules with a GPL compatible license.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
28 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
29 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
30 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
31 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
32 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
33 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
34 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
35 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
36 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
37 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
38 * DAMAGE.
39 *
Oliver Hartkoppccb29632007-11-16 15:56:08 -080040 */
41
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>
Oliver Hartkopp3ccd4c62010-01-12 02:00:46 -080048#include <linux/can/dev.h>
Oliver Hartkopp0ae89be2014-01-30 10:11:28 +010049#include <linux/can/skb.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090050#include <linux/slab.h>
Oliver Hartkoppccb29632007-11-16 15:56:08 -080051#include <net/rtnetlink.h>
52
Oliver Hartkoppccb29632007-11-16 15:56:08 -080053MODULE_DESCRIPTION("virtual CAN interface");
54MODULE_LICENSE("Dual BSD/GPL");
55MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>");
56
57
58/*
59 * CAN test feature:
60 * Enable the echo on driver level for testing the CAN core echo modes.
61 * See Documentation/networking/can.txt for details.
62 */
63
Rusty Russelleb939922011-12-19 14:08:01 +000064static bool echo; /* echo testing. Default: 0 (Off) */
Oliver Hartkoppccb29632007-11-16 15:56:08 -080065module_param(echo, bool, S_IRUGO);
66MODULE_PARM_DESC(echo, "Echo sent frames (for testing). Default: 0 (Off)");
67
68
69static void vcan_rx(struct sk_buff *skb, struct net_device *dev)
70{
Oliver Hartkopp41052ef2012-06-13 20:56:59 +020071 struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
Oliver Hartkoppccb29632007-11-16 15:56:08 -080072 struct net_device_stats *stats = &dev->stats;
73
74 stats->rx_packets++;
Oliver Hartkopp41052ef2012-06-13 20:56:59 +020075 stats->rx_bytes += cfd->len;
Oliver Hartkoppccb29632007-11-16 15:56:08 -080076
Oliver Hartkoppccb29632007-11-16 15:56:08 -080077 skb->pkt_type = PACKET_BROADCAST;
78 skb->dev = dev;
79 skb->ip_summed = CHECKSUM_UNNECESSARY;
80
Oliver Hartkopp36c01242015-06-21 18:50:44 +020081 if (!(skb->tstamp.tv64))
82 __net_timestamp(skb);
83
Oliver Hartkopp481a8192009-09-15 01:31:34 -070084 netif_rx_ni(skb);
Oliver Hartkoppccb29632007-11-16 15:56:08 -080085}
86
Stephen Hemminger424efe92009-08-31 19:50:51 +000087static netdev_tx_t vcan_tx(struct sk_buff *skb, struct net_device *dev)
Oliver Hartkoppccb29632007-11-16 15:56:08 -080088{
Oliver Hartkopp41052ef2012-06-13 20:56:59 +020089 struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
Oliver Hartkoppccb29632007-11-16 15:56:08 -080090 struct net_device_stats *stats = &dev->stats;
91 int loop;
92
Oliver Hartkopp3ccd4c62010-01-12 02:00:46 -080093 if (can_dropped_invalid_skb(dev, skb))
94 return NETDEV_TX_OK;
95
Oliver Hartkoppccb29632007-11-16 15:56:08 -080096 stats->tx_packets++;
Oliver Hartkopp41052ef2012-06-13 20:56:59 +020097 stats->tx_bytes += cfd->len;
Oliver Hartkoppccb29632007-11-16 15:56:08 -080098
99 /* set flag whether this packet has to be looped back */
100 loop = skb->pkt_type == PACKET_LOOPBACK;
101
102 if (!echo) {
103 /* no echo handling available inside this driver */
104
105 if (loop) {
106 /*
107 * only count the packets here, because the
108 * CAN core already did the echo for us
109 */
110 stats->rx_packets++;
Oliver Hartkopp41052ef2012-06-13 20:56:59 +0200111 stats->rx_bytes += cfd->len;
Oliver Hartkoppccb29632007-11-16 15:56:08 -0800112 }
Oliver Hartkopp0ae89be2014-01-30 10:11:28 +0100113 consume_skb(skb);
Oliver Hartkoppccb29632007-11-16 15:56:08 -0800114 return NETDEV_TX_OK;
115 }
116
117 /* perform standard echo handling for CAN network interfaces */
118
119 if (loop) {
Oliver Hartkoppccb29632007-11-16 15:56:08 -0800120
Oliver Hartkopp0ae89be2014-01-30 10:11:28 +0100121 skb = can_create_echo_skb(skb);
Oliver Hartkoppccb29632007-11-16 15:56:08 -0800122 if (!skb)
123 return NETDEV_TX_OK;
124
125 /* receive with packet counting */
Oliver Hartkoppccb29632007-11-16 15:56:08 -0800126 vcan_rx(skb, dev);
127 } else {
128 /* no looped packets => no counting */
Oliver Hartkopp0ae89be2014-01-30 10:11:28 +0100129 consume_skb(skb);
Oliver Hartkoppccb29632007-11-16 15:56:08 -0800130 }
131 return NETDEV_TX_OK;
132}
133
Oliver Hartkopp41052ef2012-06-13 20:56:59 +0200134static int vcan_change_mtu(struct net_device *dev, int new_mtu)
135{
136 /* Do not allow changing the MTU while running */
137 if (dev->flags & IFF_UP)
138 return -EBUSY;
139
140 if (new_mtu != CAN_MTU && new_mtu != CANFD_MTU)
141 return -EINVAL;
142
143 dev->mtu = new_mtu;
144 return 0;
145}
146
Oliver Hartkopp5ad258c2008-12-16 01:42:50 -0800147static const struct net_device_ops vcan_netdev_ops = {
148 .ndo_start_xmit = vcan_tx,
Oliver Hartkopp41052ef2012-06-13 20:56:59 +0200149 .ndo_change_mtu = vcan_change_mtu,
Oliver Hartkopp5ad258c2008-12-16 01:42:50 -0800150};
151
Oliver Hartkoppccb29632007-11-16 15:56:08 -0800152static void vcan_setup(struct net_device *dev)
153{
Oliver Hartkoppfc10af82008-12-17 15:37:55 -0800154 dev->type = ARPHRD_CAN;
Oliver Hartkopp41052ef2012-06-13 20:56:59 +0200155 dev->mtu = CAN_MTU;
Oliver Hartkoppfc10af82008-12-17 15:37:55 -0800156 dev->hard_header_len = 0;
157 dev->addr_len = 0;
158 dev->tx_queue_len = 0;
159 dev->flags = IFF_NOARP;
Oliver Hartkoppccb29632007-11-16 15:56:08 -0800160
161 /* set flags according to driver capabilities */
162 if (echo)
163 dev->flags |= IFF_ECHO;
164
Oliver Hartkoppfc10af82008-12-17 15:37:55 -0800165 dev->netdev_ops = &vcan_netdev_ops;
166 dev->destructor = free_netdev;
Oliver Hartkoppccb29632007-11-16 15:56:08 -0800167}
168
169static struct rtnl_link_ops vcan_link_ops __read_mostly = {
Oliver Hartkoppfc10af82008-12-17 15:37:55 -0800170 .kind = "vcan",
171 .setup = vcan_setup,
Oliver Hartkoppccb29632007-11-16 15:56:08 -0800172};
173
174static __init int vcan_init_module(void)
175{
Jeremiah Mahlerace9bb22014-12-03 00:44:04 -0800176 pr_info("vcan: Virtual CAN interface driver\n");
Oliver Hartkoppccb29632007-11-16 15:56:08 -0800177
178 if (echo)
179 printk(KERN_INFO "vcan: enabled echo on driver level.\n");
180
181 return rtnl_link_register(&vcan_link_ops);
182}
183
184static __exit void vcan_cleanup_module(void)
185{
186 rtnl_link_unregister(&vcan_link_ops);
187}
188
189module_init(vcan_init_module);
190module_exit(vcan_cleanup_module);