2 * vcan.c - Virtual CAN interface
4 * Copyright (c) 2002-2007 Volkswagen Group Electronic Research
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
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.
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.
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.
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
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33 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
34 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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40 * Send feedback to <socketcan-users@lists.berlios.de>
44 #include <linux/module.h>
45 #include <linux/init.h>
46 #include <linux/netdevice.h>
47 #include <linux/if_arp.h>
48 #include <linux/if_ether.h>
49 #include <linux/can.h>
50 #include <linux/can/dev.h>
51 #include <net/rtnetlink.h>
53 static __initdata
const char banner
[] =
54 KERN_INFO
"vcan: Virtual CAN interface driver\n";
56 MODULE_DESCRIPTION("virtual CAN interface");
57 MODULE_LICENSE("Dual BSD/GPL");
58 MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>");
63 * Enable the echo on driver level for testing the CAN core echo modes.
64 * See Documentation/networking/can.txt for details.
67 static int echo
; /* echo testing. Default: 0 (Off) */
68 module_param(echo
, bool, S_IRUGO
);
69 MODULE_PARM_DESC(echo
, "Echo sent frames (for testing). Default: 0 (Off)");
72 static void vcan_rx(struct sk_buff
*skb
, struct net_device
*dev
)
74 struct can_frame
*cf
= (struct can_frame
*)skb
->data
;
75 struct net_device_stats
*stats
= &dev
->stats
;
78 stats
->rx_bytes
+= cf
->can_dlc
;
80 skb
->protocol
= htons(ETH_P_CAN
);
81 skb
->pkt_type
= PACKET_BROADCAST
;
83 skb
->ip_summed
= CHECKSUM_UNNECESSARY
;
88 static netdev_tx_t
vcan_tx(struct sk_buff
*skb
, struct net_device
*dev
)
90 struct can_frame
*cf
= (struct can_frame
*)skb
->data
;
91 struct net_device_stats
*stats
= &dev
->stats
;
94 if (can_dropped_invalid_skb(dev
, skb
))
98 stats
->tx_bytes
+= cf
->can_dlc
;
100 /* set flag whether this packet has to be looped back */
101 loop
= skb
->pkt_type
== PACKET_LOOPBACK
;
104 /* no echo handling available inside this driver */
108 * only count the packets here, because the
109 * CAN core already did the echo for us
112 stats
->rx_bytes
+= cf
->can_dlc
;
118 /* perform standard echo handling for CAN network interfaces */
121 struct sock
*srcsk
= skb
->sk
;
123 skb
= skb_share_check(skb
, GFP_ATOMIC
);
127 /* receive with packet counting */
131 /* no looped packets => no counting */
137 static const struct net_device_ops vcan_netdev_ops
= {
138 .ndo_start_xmit
= vcan_tx
,
141 static void vcan_setup(struct net_device
*dev
)
143 dev
->type
= ARPHRD_CAN
;
144 dev
->mtu
= sizeof(struct can_frame
);
145 dev
->hard_header_len
= 0;
147 dev
->tx_queue_len
= 0;
148 dev
->flags
= IFF_NOARP
;
150 /* set flags according to driver capabilities */
152 dev
->flags
|= IFF_ECHO
;
154 dev
->netdev_ops
= &vcan_netdev_ops
;
155 dev
->destructor
= free_netdev
;
158 static struct rtnl_link_ops vcan_link_ops __read_mostly
= {
163 static __init
int vcan_init_module(void)
168 printk(KERN_INFO
"vcan: enabled echo on driver level.\n");
170 return rtnl_link_register(&vcan_link_ops
);
173 static __exit
void vcan_cleanup_module(void)
175 rtnl_link_unregister(&vcan_link_ops
);
178 module_init(vcan_init_module
);
179 module_exit(vcan_cleanup_module
);