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authorOliver Hartkopp <oliver.hartkopp@volkswagen.de>2007-11-16 18:56:08 -0500
committerDavid S. Miller <davem@davemloft.net>2008-01-28 17:54:12 -0500
commitccb29637991fa6b8321a80c2320a71e379aea962 (patch)
tree07a0a58adcb97c9691ec0d2a0feae5b68804ef4a /drivers/net/can
parentffd980f976e7fd666c2e61bf8ab35107efd11828 (diff)
[CAN]: Add virtual CAN netdevice driver
This patch adds the virtual CAN bus (vcan) network driver. The vcan device is just a loopback device for CAN frames, no real CAN hardware is involved. Signed-off-by: Oliver Hartkopp <oliver.hartkopp@volkswagen.de> Signed-off-by: Urs Thuermann <urs.thuermann@volkswagen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/can')
-rw-r--r--drivers/net/can/Kconfig25
-rw-r--r--drivers/net/can/Makefile5
-rw-r--r--drivers/net/can/vcan.c169
3 files changed, 199 insertions, 0 deletions
diff --git a/drivers/net/can/Kconfig b/drivers/net/can/Kconfig
new file mode 100644
index 000000000000..57def0d57371
--- /dev/null
+++ b/drivers/net/can/Kconfig
@@ -0,0 +1,25 @@
1menu "CAN Device Drivers"
2 depends on CAN
3
4config CAN_VCAN
5 tristate "Virtual Local CAN Interface (vcan)"
6 depends on CAN
7 default N
8 ---help---
9 Similar to the network loopback devices, vcan offers a
10 virtual local CAN interface.
11
12 This driver can also be built as a module. If so, the module
13 will be called vcan.
14
15config CAN_DEBUG_DEVICES
16 bool "CAN devices debugging messages"
17 depends on CAN
18 default N
19 ---help---
20 Say Y here if you want the CAN device drivers to produce a bunch of
21 debug messages to the system log. Select this if you are having
22 a problem with CAN support and want to see more of what is going
23 on.
24
25endmenu
diff --git a/drivers/net/can/Makefile b/drivers/net/can/Makefile
new file mode 100644
index 000000000000..c4bead705cd9
--- /dev/null
+++ b/drivers/net/can/Makefile
@@ -0,0 +1,5 @@
1#
2# Makefile for the Linux Controller Area Network drivers.
3#
4
5obj-$(CONFIG_CAN_VCAN) += vcan.o
diff --git a/drivers/net/can/vcan.c b/drivers/net/can/vcan.c
new file mode 100644
index 000000000000..103f0f1df280
--- /dev/null
+++ b/drivers/net/can/vcan.c
@@ -0,0 +1,169 @@
1/*
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 *
40 * Send feedback to <socketcan-users@lists.berlios.de>
41 *
42 */
43
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 <net/rtnetlink.h>
51
52static __initdata const char banner[] =
53 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
66static int echo; /* echo testing. Default: 0 (Off) */
67module_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{
73 struct net_device_stats *stats = &dev->stats;
74
75 stats->rx_packets++;
76 stats->rx_bytes += skb->len;
77
78 skb->protocol = htons(ETH_P_CAN);
79 skb->pkt_type = PACKET_BROADCAST;
80 skb->dev = dev;
81 skb->ip_summed = CHECKSUM_UNNECESSARY;
82
83 netif_rx(skb);
84}
85
86static int vcan_tx(struct sk_buff *skb, struct net_device *dev)
87{
88 struct net_device_stats *stats = &dev->stats;
89 int loop;
90
91 stats->tx_packets++;
92 stats->tx_bytes += skb->len;
93
94 /* set flag whether this packet has to be looped back */
95 loop = skb->pkt_type == PACKET_LOOPBACK;
96
97 if (!echo) {
98 /* no echo handling available inside this driver */
99
100 if (loop) {
101 /*
102 * only count the packets here, because the
103 * CAN core already did the echo for us
104 */
105 stats->rx_packets++;
106 stats->rx_bytes += skb->len;
107 }
108 kfree_skb(skb);
109 return NETDEV_TX_OK;
110 }
111
112 /* perform standard echo handling for CAN network interfaces */
113
114 if (loop) {
115 struct sock *srcsk = skb->sk;
116
117 skb = skb_share_check(skb, GFP_ATOMIC);
118 if (!skb)
119 return NETDEV_TX_OK;
120
121 /* receive with packet counting */
122 skb->sk = srcsk;
123 vcan_rx(skb, dev);
124 } else {
125 /* no looped packets => no counting */
126 kfree_skb(skb);
127 }
128 return NETDEV_TX_OK;
129}
130
131static void vcan_setup(struct net_device *dev)
132{
133 dev->type = ARPHRD_CAN;
134 dev->mtu = sizeof(struct can_frame);
135 dev->hard_header_len = 0;
136 dev->addr_len = 0;
137 dev->tx_queue_len = 0;
138 dev->flags = IFF_NOARP;
139
140 /* set flags according to driver capabilities */
141 if (echo)
142 dev->flags |= IFF_ECHO;
143
144 dev->hard_start_xmit = vcan_tx;
145 dev->destructor = free_netdev;
146}
147
148static struct rtnl_link_ops vcan_link_ops __read_mostly = {
149 .kind = "vcan",
150 .setup = vcan_setup,
151};
152
153static __init int vcan_init_module(void)
154{
155 printk(banner);
156
157 if (echo)
158 printk(KERN_INFO "vcan: enabled echo on driver level.\n");
159
160 return rtnl_link_register(&vcan_link_ops);
161}
162
163static __exit void vcan_cleanup_module(void)
164{
165 rtnl_link_unregister(&vcan_link_ops);
166}
167
168module_init(vcan_init_module);
169module_exit(vcan_cleanup_module);