1 | /* vcan.c - Virtual CAN interface |
2 | * |
3 | * Copyright (c) 2002-2017 Volkswagen Group Electronic Research |
4 | * All rights reserved. |
5 | * |
6 | * Redistribution and use in source and binary forms, with or without |
7 | * modification, are permitted provided that the following conditions |
8 | * are met: |
9 | * 1. Redistributions of source code must retain the above copyright |
10 | * notice, this list of conditions and the following disclaimer. |
11 | * 2. Redistributions in binary form must reproduce the above copyright |
12 | * notice, this list of conditions and the following disclaimer in the |
13 | * documentation and/or other materials provided with the distribution. |
14 | * 3. Neither the name of Volkswagen nor the names of its contributors |
15 | * may be used to endorse or promote products derived from this software |
16 | * without specific prior written permission. |
17 | * |
18 | * Alternatively, provided that this notice is retained in full, this |
19 | * software may be distributed under the terms of the GNU General |
20 | * Public License ("GPL") version 2, in which case the provisions of the |
21 | * GPL apply INSTEAD OF those given above. |
22 | * |
23 | * The provided data structures and external interfaces from this code |
24 | * are not restricted to be used by modules with a GPL compatible license. |
25 | * |
26 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
27 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
28 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
29 | * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
30 | * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
31 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
32 | * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
33 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
34 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
35 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
36 | * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH |
37 | * DAMAGE. |
38 | * |
39 | */ |
40 | |
41 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
42 | |
43 | #include <linux/ethtool.h> |
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/can-ml.h> |
51 | #include <linux/can/dev.h> |
52 | #include <linux/can/skb.h> |
53 | #include <linux/slab.h> |
54 | #include <net/rtnetlink.h> |
55 | |
56 | #define DRV_NAME "vcan" |
57 | |
58 | MODULE_DESCRIPTION("virtual CAN interface" ); |
59 | MODULE_LICENSE("Dual BSD/GPL" ); |
60 | MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>" ); |
61 | MODULE_ALIAS_RTNL_LINK(DRV_NAME); |
62 | |
63 | /* CAN test feature: |
64 | * Enable the echo on driver level for testing the CAN core echo modes. |
65 | * See Documentation/networking/can.rst for details. |
66 | */ |
67 | |
68 | static bool echo; /* echo testing. Default: 0 (Off) */ |
69 | module_param(echo, bool, 0444); |
70 | MODULE_PARM_DESC(echo, "Echo sent frames (for testing). Default: 0 (Off)" ); |
71 | |
72 | static void vcan_rx(struct sk_buff *skb, struct net_device *dev) |
73 | { |
74 | struct net_device_stats *stats = &dev->stats; |
75 | |
76 | stats->rx_packets++; |
77 | stats->rx_bytes += can_skb_get_data_len(skb); |
78 | |
79 | skb->pkt_type = PACKET_BROADCAST; |
80 | skb->dev = dev; |
81 | skb->ip_summed = CHECKSUM_UNNECESSARY; |
82 | |
83 | netif_rx(skb); |
84 | } |
85 | |
86 | static netdev_tx_t vcan_tx(struct sk_buff *skb, struct net_device *dev) |
87 | { |
88 | struct net_device_stats *stats = &dev->stats; |
89 | unsigned int len; |
90 | int loop; |
91 | |
92 | if (can_dropped_invalid_skb(dev, skb)) |
93 | return NETDEV_TX_OK; |
94 | |
95 | len = can_skb_get_data_len(skb); |
96 | stats->tx_packets++; |
97 | stats->tx_bytes += len; |
98 | |
99 | /* set flag whether this packet has to be looped back */ |
100 | loop = skb->pkt_type == PACKET_LOOPBACK; |
101 | |
102 | skb_tx_timestamp(skb); |
103 | |
104 | if (!echo) { |
105 | /* no echo handling available inside this driver */ |
106 | if (loop) { |
107 | /* only count the packets here, because the |
108 | * CAN core already did the echo for us |
109 | */ |
110 | stats->rx_packets++; |
111 | stats->rx_bytes += len; |
112 | } |
113 | consume_skb(skb); |
114 | return NETDEV_TX_OK; |
115 | } |
116 | |
117 | /* perform standard echo handling for CAN network interfaces */ |
118 | |
119 | if (loop) { |
120 | skb = can_create_echo_skb(skb); |
121 | if (!skb) |
122 | return NETDEV_TX_OK; |
123 | |
124 | /* receive with packet counting */ |
125 | vcan_rx(skb, dev); |
126 | } else { |
127 | /* no looped packets => no counting */ |
128 | consume_skb(skb); |
129 | } |
130 | return NETDEV_TX_OK; |
131 | } |
132 | |
133 | static int vcan_change_mtu(struct net_device *dev, int new_mtu) |
134 | { |
135 | /* Do not allow changing the MTU while running */ |
136 | if (dev->flags & IFF_UP) |
137 | return -EBUSY; |
138 | |
139 | if (new_mtu != CAN_MTU && new_mtu != CANFD_MTU && |
140 | !can_is_canxl_dev_mtu(mtu: new_mtu)) |
141 | return -EINVAL; |
142 | |
143 | dev->mtu = new_mtu; |
144 | return 0; |
145 | } |
146 | |
147 | static const struct net_device_ops vcan_netdev_ops = { |
148 | .ndo_start_xmit = vcan_tx, |
149 | .ndo_change_mtu = vcan_change_mtu, |
150 | }; |
151 | |
152 | static const struct ethtool_ops vcan_ethtool_ops = { |
153 | .get_ts_info = ethtool_op_get_ts_info, |
154 | }; |
155 | |
156 | static void vcan_setup(struct net_device *dev) |
157 | { |
158 | dev->type = ARPHRD_CAN; |
159 | dev->mtu = CANFD_MTU; |
160 | dev->hard_header_len = 0; |
161 | dev->addr_len = 0; |
162 | dev->tx_queue_len = 0; |
163 | dev->flags = IFF_NOARP; |
164 | can_set_ml_priv(dev, ml_priv: netdev_priv(dev)); |
165 | |
166 | /* set flags according to driver capabilities */ |
167 | if (echo) |
168 | dev->flags |= IFF_ECHO; |
169 | |
170 | dev->netdev_ops = &vcan_netdev_ops; |
171 | dev->ethtool_ops = &vcan_ethtool_ops; |
172 | dev->needs_free_netdev = true; |
173 | } |
174 | |
175 | static struct rtnl_link_ops vcan_link_ops __read_mostly = { |
176 | .kind = DRV_NAME, |
177 | .priv_size = sizeof(struct can_ml_priv), |
178 | .setup = vcan_setup, |
179 | }; |
180 | |
181 | static __init int vcan_init_module(void) |
182 | { |
183 | pr_info("Virtual CAN interface driver\n" ); |
184 | |
185 | if (echo) |
186 | pr_info("enabled echo on driver level.\n" ); |
187 | |
188 | return rtnl_link_register(ops: &vcan_link_ops); |
189 | } |
190 | |
191 | static __exit void vcan_cleanup_module(void) |
192 | { |
193 | rtnl_link_unregister(ops: &vcan_link_ops); |
194 | } |
195 | |
196 | module_init(vcan_init_module); |
197 | module_exit(vcan_cleanup_module); |
198 | |