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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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090049#include <linux/slab.h>
Oliver Hartkoppccb29632007-11-16 15:56:08 -080050#include <net/rtnetlink.h>
51
Andi Kleenc477ebd2012-10-04 17:11:55 -070052static __initconst const char banner[] =
Oliver Hartkoppccb29632007-11-16 15:56:08 -080053 KERN_INFO "vcan: Virtual CAN interface driver\n";
54
55MODULE_DESCRIPTION("virtual CAN interface");
56MODULE_LICENSE("Dual BSD/GPL");
57MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>");
58
59
60/*
61 * CAN test feature:
62 * Enable the echo on driver level for testing the CAN core echo modes.
63 * See Documentation/networking/can.txt for details.
64 */
65
Rusty Russelleb939922011-12-19 14:08:01 +000066static bool echo; /* echo testing. Default: 0 (Off) */
Oliver Hartkoppccb29632007-11-16 15:56:08 -080067module_param(echo, bool, S_IRUGO);
68MODULE_PARM_DESC(echo, "Echo sent frames (for testing). Default: 0 (Off)");
69
70
71static void vcan_rx(struct sk_buff *skb, struct net_device *dev)
72{
Oliver Hartkopp41052ef2012-06-13 20:56:59 +020073 struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
Oliver Hartkoppccb29632007-11-16 15:56:08 -080074 struct net_device_stats *stats = &dev->stats;
75
76 stats->rx_packets++;
Oliver Hartkopp41052ef2012-06-13 20:56:59 +020077 stats->rx_bytes += cfd->len;
Oliver Hartkoppccb29632007-11-16 15:56:08 -080078
Oliver Hartkoppccb29632007-11-16 15:56:08 -080079 skb->pkt_type = PACKET_BROADCAST;
80 skb->dev = dev;
81 skb->ip_summed = CHECKSUM_UNNECESSARY;
82
Oliver Hartkopp481a8192009-09-15 01:31:34 -070083 netif_rx_ni(skb);
Oliver Hartkoppccb29632007-11-16 15:56:08 -080084}
85
Stephen Hemminger424efe92009-08-31 19:50:51 +000086static netdev_tx_t vcan_tx(struct sk_buff *skb, struct net_device *dev)
Oliver Hartkoppccb29632007-11-16 15:56:08 -080087{
Oliver Hartkopp41052ef2012-06-13 20:56:59 +020088 struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
Oliver Hartkoppccb29632007-11-16 15:56:08 -080089 struct net_device_stats *stats = &dev->stats;
90 int loop;
91
Oliver Hartkopp3ccd4c62010-01-12 02:00:46 -080092 if (can_dropped_invalid_skb(dev, skb))
93 return NETDEV_TX_OK;
94
Oliver Hartkoppccb29632007-11-16 15:56:08 -080095 stats->tx_packets++;
Oliver Hartkopp41052ef2012-06-13 20:56:59 +020096 stats->tx_bytes += cfd->len;
Oliver Hartkoppccb29632007-11-16 15:56:08 -080097
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 */
103
104 if (loop) {
105 /*
106 * only count the packets here, because the
107 * CAN core already did the echo for us
108 */
109 stats->rx_packets++;
Oliver Hartkopp41052ef2012-06-13 20:56:59 +0200110 stats->rx_bytes += cfd->len;
Oliver Hartkoppccb29632007-11-16 15:56:08 -0800111 }
112 kfree_skb(skb);
113 return NETDEV_TX_OK;
114 }
115
116 /* perform standard echo handling for CAN network interfaces */
117
118 if (loop) {
119 struct sock *srcsk = skb->sk;
120
121 skb = skb_share_check(skb, GFP_ATOMIC);
122 if (!skb)
123 return NETDEV_TX_OK;
124
125 /* receive with packet counting */
126 skb->sk = srcsk;
127 vcan_rx(skb, dev);
128 } else {
129 /* no looped packets => no counting */
130 kfree_skb(skb);
131 }
132 return NETDEV_TX_OK;
133}
134
Oliver Hartkopp41052ef2012-06-13 20:56:59 +0200135static int vcan_change_mtu(struct net_device *dev, int new_mtu)
136{
137 /* Do not allow changing the MTU while running */
138 if (dev->flags & IFF_UP)
139 return -EBUSY;
140
141 if (new_mtu != CAN_MTU && new_mtu != CANFD_MTU)
142 return -EINVAL;
143
144 dev->mtu = new_mtu;
145 return 0;
146}
147
Oliver Hartkopp5ad258c2008-12-16 01:42:50 -0800148static const struct net_device_ops vcan_netdev_ops = {
149 .ndo_start_xmit = vcan_tx,
Oliver Hartkopp41052ef2012-06-13 20:56:59 +0200150 .ndo_change_mtu = vcan_change_mtu,
Oliver Hartkopp5ad258c2008-12-16 01:42:50 -0800151};
152
Oliver Hartkoppccb29632007-11-16 15:56:08 -0800153static void vcan_setup(struct net_device *dev)
154{
Oliver Hartkoppfc10af82008-12-17 15:37:55 -0800155 dev->type = ARPHRD_CAN;
Oliver Hartkopp41052ef2012-06-13 20:56:59 +0200156 dev->mtu = CAN_MTU;
Oliver Hartkoppfc10af82008-12-17 15:37:55 -0800157 dev->hard_header_len = 0;
158 dev->addr_len = 0;
159 dev->tx_queue_len = 0;
160 dev->flags = IFF_NOARP;
Oliver Hartkoppccb29632007-11-16 15:56:08 -0800161
162 /* set flags according to driver capabilities */
163 if (echo)
164 dev->flags |= IFF_ECHO;
165
Oliver Hartkoppfc10af82008-12-17 15:37:55 -0800166 dev->netdev_ops = &vcan_netdev_ops;
167 dev->destructor = free_netdev;
Oliver Hartkoppccb29632007-11-16 15:56:08 -0800168}
169
170static struct rtnl_link_ops vcan_link_ops __read_mostly = {
Oliver Hartkoppfc10af82008-12-17 15:37:55 -0800171 .kind = "vcan",
172 .setup = vcan_setup,
Oliver Hartkoppccb29632007-11-16 15:56:08 -0800173};
174
175static __init int vcan_init_module(void)
176{
177 printk(banner);
178
179 if (echo)
180 printk(KERN_INFO "vcan: enabled echo on driver level.\n");
181
182 return rtnl_link_register(&vcan_link_ops);
183}
184
185static __exit void vcan_cleanup_module(void)
186{
187 rtnl_link_unregister(&vcan_link_ops);
188}
189
190module_init(vcan_init_module);
191module_exit(vcan_cleanup_module);