1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
|
/* vcan.c - Virtual CAN interface
*
* Copyright (c) 2002-2017 Volkswagen Group Electronic Research
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Volkswagen nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* Alternatively, provided that this notice is retained in full, this
* software may be distributed under the terms of the GNU General
* Public License ("GPL") version 2, in which case the provisions of the
* GPL apply INSTEAD OF those given above.
*
* The provided data structures and external interfaces from this code
* are not restricted to be used by modules with a GPL compatible license.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/init.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/if_ether.h>
#include <linux/can.h>
#include <linux/can/can-ml.h>
#include <linux/can/dev.h>
#include <linux/can/skb.h>
#include <linux/slab.h>
#include <net/rtnetlink.h>
#define DRV_NAME "vcan"
MODULE_DESCRIPTION("virtual CAN interface");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>");
MODULE_ALIAS_RTNL_LINK(DRV_NAME);
/* CAN test feature:
* Enable the echo on driver level for testing the CAN core echo modes.
* See Documentation/networking/can.rst for details.
*/
static bool echo; /* echo testing. Default: 0 (Off) */
module_param(echo, bool, 0444);
MODULE_PARM_DESC(echo, "Echo sent frames (for testing). Default: 0 (Off)");
static void vcan_rx(struct sk_buff *skb, struct net_device *dev)
{
struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
struct net_device_stats *stats = &dev->stats;
stats->rx_packets++;
stats->rx_bytes += cfd->len;
skb->pkt_type = PACKET_BROADCAST;
skb->dev = dev;
skb->ip_summed = CHECKSUM_UNNECESSARY;
netif_rx_ni(skb);
}
static netdev_tx_t vcan_tx(struct sk_buff *skb, struct net_device *dev)
{
struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
struct net_device_stats *stats = &dev->stats;
int loop, len;
if (can_dropped_invalid_skb(dev, skb))
return NETDEV_TX_OK;
len = cfd->can_id & CAN_RTR_FLAG ? 0 : cfd->len;
stats->tx_packets++;
stats->tx_bytes += len;
/* set flag whether this packet has to be looped back */
loop = skb->pkt_type == PACKET_LOOPBACK;
if (!echo) {
/* no echo handling available inside this driver */
if (loop) {
/* only count the packets here, because the
* CAN core already did the echo for us
*/
stats->rx_packets++;
stats->rx_bytes += len;
}
consume_skb(skb);
return NETDEV_TX_OK;
}
/* perform standard echo handling for CAN network interfaces */
if (loop) {
skb = can_create_echo_skb(skb);
if (!skb)
return NETDEV_TX_OK;
/* receive with packet counting */
vcan_rx(skb, dev);
} else {
/* no looped packets => no counting */
consume_skb(skb);
}
return NETDEV_TX_OK;
}
static int vcan_change_mtu(struct net_device *dev, int new_mtu)
{
/* Do not allow changing the MTU while running */
if (dev->flags & IFF_UP)
return -EBUSY;
if (new_mtu != CAN_MTU && new_mtu != CANFD_MTU)
return -EINVAL;
dev->mtu = new_mtu;
return 0;
}
static const struct net_device_ops vcan_netdev_ops = {
.ndo_start_xmit = vcan_tx,
.ndo_change_mtu = vcan_change_mtu,
};
static void vcan_setup(struct net_device *dev)
{
dev->type = ARPHRD_CAN;
dev->mtu = CANFD_MTU;
dev->hard_header_len = 0;
dev->addr_len = 0;
dev->tx_queue_len = 0;
dev->flags = IFF_NOARP;
can_set_ml_priv(dev, netdev_priv(dev));
/* set flags according to driver capabilities */
if (echo)
dev->flags |= IFF_ECHO;
dev->netdev_ops = &vcan_netdev_ops;
dev->needs_free_netdev = true;
}
static struct rtnl_link_ops vcan_link_ops __read_mostly = {
.kind = DRV_NAME,
.priv_size = sizeof(struct can_ml_priv),
.setup = vcan_setup,
};
static __init int vcan_init_module(void)
{
pr_info("Virtual CAN interface driver\n");
if (echo)
pr_info("enabled echo on driver level.\n");
return rtnl_link_register(&vcan_link_ops);
}
static __exit void vcan_cleanup_module(void)
{
rtnl_link_unregister(&vcan_link_ops);
}
module_init(vcan_init_module);
module_exit(vcan_cleanup_module);
|
