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ccb29637 OH |
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> | |
3ccd4c61 | 50 | #include <linux/can/dev.h> |
5a0e3ad6 | 51 | #include <linux/slab.h> |
ccb29637 OH |
52 | #include <net/rtnetlink.h> |
53 | ||
54 | static __initdata const char banner[] = | |
55 | KERN_INFO "vcan: Virtual CAN interface driver\n"; | |
56 | ||
57 | MODULE_DESCRIPTION("virtual CAN interface"); | |
58 | MODULE_LICENSE("Dual BSD/GPL"); | |
59 | MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>"); | |
60 | ||
61 | ||
62 | /* | |
63 | * CAN test feature: | |
64 | * Enable the echo on driver level for testing the CAN core echo modes. | |
65 | * See Documentation/networking/can.txt for details. | |
66 | */ | |
67 | ||
68 | static int echo; /* echo testing. Default: 0 (Off) */ | |
69 | module_param(echo, bool, S_IRUGO); | |
70 | MODULE_PARM_DESC(echo, "Echo sent frames (for testing). Default: 0 (Off)"); | |
71 | ||
72 | ||
73 | static void vcan_rx(struct sk_buff *skb, struct net_device *dev) | |
74 | { | |
3ccd4c61 | 75 | struct can_frame *cf = (struct can_frame *)skb->data; |
ccb29637 OH |
76 | struct net_device_stats *stats = &dev->stats; |
77 | ||
78 | stats->rx_packets++; | |
3ccd4c61 | 79 | stats->rx_bytes += cf->can_dlc; |
ccb29637 OH |
80 | |
81 | skb->protocol = htons(ETH_P_CAN); | |
82 | skb->pkt_type = PACKET_BROADCAST; | |
83 | skb->dev = dev; | |
84 | skb->ip_summed = CHECKSUM_UNNECESSARY; | |
85 | ||
481a8199 | 86 | netif_rx_ni(skb); |
ccb29637 OH |
87 | } |
88 | ||
424efe9c | 89 | static netdev_tx_t vcan_tx(struct sk_buff *skb, struct net_device *dev) |
ccb29637 | 90 | { |
3ccd4c61 | 91 | struct can_frame *cf = (struct can_frame *)skb->data; |
ccb29637 OH |
92 | struct net_device_stats *stats = &dev->stats; |
93 | int loop; | |
94 | ||
3ccd4c61 OH |
95 | if (can_dropped_invalid_skb(dev, skb)) |
96 | return NETDEV_TX_OK; | |
97 | ||
ccb29637 | 98 | stats->tx_packets++; |
3ccd4c61 | 99 | stats->tx_bytes += cf->can_dlc; |
ccb29637 OH |
100 | |
101 | /* set flag whether this packet has to be looped back */ | |
102 | loop = skb->pkt_type == PACKET_LOOPBACK; | |
103 | ||
104 | if (!echo) { | |
105 | /* no echo handling available inside this driver */ | |
106 | ||
107 | if (loop) { | |
108 | /* | |
109 | * only count the packets here, because the | |
110 | * CAN core already did the echo for us | |
111 | */ | |
112 | stats->rx_packets++; | |
3ccd4c61 | 113 | stats->rx_bytes += cf->can_dlc; |
ccb29637 OH |
114 | } |
115 | kfree_skb(skb); | |
116 | return NETDEV_TX_OK; | |
117 | } | |
118 | ||
119 | /* perform standard echo handling for CAN network interfaces */ | |
120 | ||
121 | if (loop) { | |
122 | struct sock *srcsk = skb->sk; | |
123 | ||
124 | skb = skb_share_check(skb, GFP_ATOMIC); | |
125 | if (!skb) | |
126 | return NETDEV_TX_OK; | |
127 | ||
128 | /* receive with packet counting */ | |
129 | skb->sk = srcsk; | |
130 | vcan_rx(skb, dev); | |
131 | } else { | |
132 | /* no looped packets => no counting */ | |
133 | kfree_skb(skb); | |
134 | } | |
135 | return NETDEV_TX_OK; | |
136 | } | |
137 | ||
5ad258c0 OH |
138 | static const struct net_device_ops vcan_netdev_ops = { |
139 | .ndo_start_xmit = vcan_tx, | |
140 | }; | |
141 | ||
ccb29637 OH |
142 | static void vcan_setup(struct net_device *dev) |
143 | { | |
fc10af8e OH |
144 | dev->type = ARPHRD_CAN; |
145 | dev->mtu = sizeof(struct can_frame); | |
146 | dev->hard_header_len = 0; | |
147 | dev->addr_len = 0; | |
148 | dev->tx_queue_len = 0; | |
149 | dev->flags = IFF_NOARP; | |
ccb29637 OH |
150 | |
151 | /* set flags according to driver capabilities */ | |
152 | if (echo) | |
153 | dev->flags |= IFF_ECHO; | |
154 | ||
fc10af8e OH |
155 | dev->netdev_ops = &vcan_netdev_ops; |
156 | dev->destructor = free_netdev; | |
ccb29637 OH |
157 | } |
158 | ||
159 | static struct rtnl_link_ops vcan_link_ops __read_mostly = { | |
fc10af8e OH |
160 | .kind = "vcan", |
161 | .setup = vcan_setup, | |
ccb29637 OH |
162 | }; |
163 | ||
164 | static __init int vcan_init_module(void) | |
165 | { | |
166 | printk(banner); | |
167 | ||
168 | if (echo) | |
169 | printk(KERN_INFO "vcan: enabled echo on driver level.\n"); | |
170 | ||
171 | return rtnl_link_register(&vcan_link_ops); | |
172 | } | |
173 | ||
174 | static __exit void vcan_cleanup_module(void) | |
175 | { | |
176 | rtnl_link_unregister(&vcan_link_ops); | |
177 | } | |
178 | ||
179 | module_init(vcan_init_module); | |
180 | module_exit(vcan_cleanup_module); |