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
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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
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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/dev.h>
49 #include <linux/can/skb.h>
50 #include <linux/slab.h>
51 #include <net/rtnetlink.h>
53 MODULE_DESCRIPTION("virtual CAN interface");
54 MODULE_LICENSE("Dual BSD/GPL");
55 MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>");
60 * Enable the echo on driver level for testing the CAN core echo modes.
61 * See Documentation/networking/can.txt for details.
64 static bool echo
; /* echo testing. Default: 0 (Off) */
65 module_param(echo
, bool, S_IRUGO
);
66 MODULE_PARM_DESC(echo
, "Echo sent frames (for testing). Default: 0 (Off)");
69 static void vcan_rx(struct sk_buff
*skb
, struct net_device
*dev
)
71 struct canfd_frame
*cfd
= (struct canfd_frame
*)skb
->data
;
72 struct net_device_stats
*stats
= &dev
->stats
;
75 stats
->rx_bytes
+= cfd
->len
;
77 skb
->pkt_type
= PACKET_BROADCAST
;
79 skb
->ip_summed
= CHECKSUM_UNNECESSARY
;
81 if (!(skb
->tstamp
.tv64
))
87 static netdev_tx_t
vcan_tx(struct sk_buff
*skb
, struct net_device
*dev
)
89 struct canfd_frame
*cfd
= (struct canfd_frame
*)skb
->data
;
90 struct net_device_stats
*stats
= &dev
->stats
;
93 if (can_dropped_invalid_skb(dev
, skb
))
97 stats
->tx_bytes
+= cfd
->len
;
99 /* set flag whether this packet has to be looped back */
100 loop
= skb
->pkt_type
== PACKET_LOOPBACK
;
103 /* no echo handling available inside this driver */
107 * only count the packets here, because the
108 * CAN core already did the echo for us
111 stats
->rx_bytes
+= cfd
->len
;
117 /* perform standard echo handling for CAN network interfaces */
121 skb
= can_create_echo_skb(skb
);
125 /* receive with packet counting */
128 /* no looped packets => no counting */
134 static int vcan_change_mtu(struct net_device
*dev
, int new_mtu
)
136 /* Do not allow changing the MTU while running */
137 if (dev
->flags
& IFF_UP
)
140 if (new_mtu
!= CAN_MTU
&& new_mtu
!= CANFD_MTU
)
147 static const struct net_device_ops vcan_netdev_ops
= {
148 .ndo_start_xmit
= vcan_tx
,
149 .ndo_change_mtu
= vcan_change_mtu
,
152 static void vcan_setup(struct net_device
*dev
)
154 dev
->type
= ARPHRD_CAN
;
156 dev
->hard_header_len
= 0;
158 dev
->tx_queue_len
= 0;
159 dev
->flags
= IFF_NOARP
;
161 /* set flags according to driver capabilities */
163 dev
->flags
|= IFF_ECHO
;
165 dev
->netdev_ops
= &vcan_netdev_ops
;
166 dev
->destructor
= free_netdev
;
169 static struct rtnl_link_ops vcan_link_ops __read_mostly
= {
174 static __init
int vcan_init_module(void)
176 pr_info("vcan: Virtual CAN interface driver\n");
179 printk(KERN_INFO
"vcan: enabled echo on driver level.\n");
181 return rtnl_link_register(&vcan_link_ops
);
184 static __exit
void vcan_cleanup_module(void)
186 rtnl_link_unregister(&vcan_link_ops
);
189 module_init(vcan_init_module
);
190 module_exit(vcan_cleanup_module
);