1
2
3
4
5
6
7
8
9
10
11
12#include <linux/module.h>
13#include <linux/init.h>
14#include <linux/netdevice.h>
15#include <linux/if_arp.h>
16#include <linux/if_ether.h>
17#include <linux/can.h>
18#include <linux/can/dev.h>
19#include <linux/can/skb.h>
20#include <linux/can/vxcan.h>
21#include <linux/can/can-ml.h>
22#include <linux/slab.h>
23#include <net/rtnetlink.h>
24
25#define DRV_NAME "vxcan"
26
27MODULE_DESCRIPTION("Virtual CAN Tunnel");
28MODULE_LICENSE("GPL");
29MODULE_AUTHOR("Oliver Hartkopp <socketcan@hartkopp.net>");
30MODULE_ALIAS_RTNL_LINK(DRV_NAME);
31
32struct vxcan_priv {
33 struct net_device __rcu *peer;
34};
35
36static netdev_tx_t vxcan_xmit(struct sk_buff *skb, struct net_device *dev)
37{
38 struct vxcan_priv *priv = netdev_priv(dev);
39 struct net_device *peer;
40 struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
41 struct net_device_stats *peerstats, *srcstats = &dev->stats;
42
43 if (can_dropped_invalid_skb(dev, skb))
44 return NETDEV_TX_OK;
45
46 rcu_read_lock();
47 peer = rcu_dereference(priv->peer);
48 if (unlikely(!peer)) {
49 kfree_skb(skb);
50 dev->stats.tx_dropped++;
51 goto out_unlock;
52 }
53
54 skb = can_create_echo_skb(skb);
55 if (!skb)
56 goto out_unlock;
57
58
59 skb->csum_start = 0;
60 skb->pkt_type = PACKET_BROADCAST;
61 skb->dev = peer;
62 skb->ip_summed = CHECKSUM_UNNECESSARY;
63
64 if (netif_rx_ni(skb) == NET_RX_SUCCESS) {
65 srcstats->tx_packets++;
66 srcstats->tx_bytes += cfd->len;
67 peerstats = &peer->stats;
68 peerstats->rx_packets++;
69 peerstats->rx_bytes += cfd->len;
70 }
71
72out_unlock:
73 rcu_read_unlock();
74 return NETDEV_TX_OK;
75}
76
77
78static int vxcan_open(struct net_device *dev)
79{
80 struct vxcan_priv *priv = netdev_priv(dev);
81 struct net_device *peer = rtnl_dereference(priv->peer);
82
83 if (!peer)
84 return -ENOTCONN;
85
86 if (peer->flags & IFF_UP) {
87 netif_carrier_on(dev);
88 netif_carrier_on(peer);
89 }
90 return 0;
91}
92
93static int vxcan_close(struct net_device *dev)
94{
95 struct vxcan_priv *priv = netdev_priv(dev);
96 struct net_device *peer = rtnl_dereference(priv->peer);
97
98 netif_carrier_off(dev);
99 if (peer)
100 netif_carrier_off(peer);
101
102 return 0;
103}
104
105static int vxcan_get_iflink(const struct net_device *dev)
106{
107 struct vxcan_priv *priv = netdev_priv(dev);
108 struct net_device *peer;
109 int iflink;
110
111 rcu_read_lock();
112 peer = rcu_dereference(priv->peer);
113 iflink = peer ? peer->ifindex : 0;
114 rcu_read_unlock();
115
116 return iflink;
117}
118
119static int vxcan_change_mtu(struct net_device *dev, int new_mtu)
120{
121
122 if (dev->flags & IFF_UP)
123 return -EBUSY;
124
125 if (new_mtu != CAN_MTU && new_mtu != CANFD_MTU)
126 return -EINVAL;
127
128 dev->mtu = new_mtu;
129 return 0;
130}
131
132static const struct net_device_ops vxcan_netdev_ops = {
133 .ndo_open = vxcan_open,
134 .ndo_stop = vxcan_close,
135 .ndo_start_xmit = vxcan_xmit,
136 .ndo_get_iflink = vxcan_get_iflink,
137 .ndo_change_mtu = vxcan_change_mtu,
138};
139
140static void vxcan_setup(struct net_device *dev)
141{
142 dev->type = ARPHRD_CAN;
143 dev->mtu = CANFD_MTU;
144 dev->hard_header_len = 0;
145 dev->addr_len = 0;
146 dev->tx_queue_len = 0;
147 dev->flags = (IFF_NOARP|IFF_ECHO);
148 dev->netdev_ops = &vxcan_netdev_ops;
149 dev->needs_free_netdev = true;
150 dev->ml_priv = netdev_priv(dev) + ALIGN(sizeof(struct vxcan_priv), NETDEV_ALIGN);
151}
152
153
154static struct rtnl_link_ops vxcan_link_ops;
155
156static int vxcan_newlink(struct net *net, struct net_device *dev,
157 struct nlattr *tb[], struct nlattr *data[],
158 struct netlink_ext_ack *extack)
159{
160 struct vxcan_priv *priv;
161 struct net_device *peer;
162 struct net *peer_net;
163
164 struct nlattr *peer_tb[IFLA_MAX + 1], **tbp = tb;
165 char ifname[IFNAMSIZ];
166 unsigned char name_assign_type;
167 struct ifinfomsg *ifmp = NULL;
168 int err;
169
170
171 if (data && data[VXCAN_INFO_PEER]) {
172 struct nlattr *nla_peer;
173
174 nla_peer = data[VXCAN_INFO_PEER];
175 ifmp = nla_data(nla_peer);
176 err = rtnl_nla_parse_ifla(peer_tb,
177 nla_data(nla_peer) +
178 sizeof(struct ifinfomsg),
179 nla_len(nla_peer) -
180 sizeof(struct ifinfomsg),
181 NULL);
182 if (err < 0)
183 return err;
184
185 tbp = peer_tb;
186 }
187
188 if (ifmp && tbp[IFLA_IFNAME]) {
189 nla_strlcpy(ifname, tbp[IFLA_IFNAME], IFNAMSIZ);
190 name_assign_type = NET_NAME_USER;
191 } else {
192 snprintf(ifname, IFNAMSIZ, DRV_NAME "%%d");
193 name_assign_type = NET_NAME_ENUM;
194 }
195
196 peer_net = rtnl_link_get_net(net, tbp);
197 if (IS_ERR(peer_net))
198 return PTR_ERR(peer_net);
199
200 peer = rtnl_create_link(peer_net, ifname, name_assign_type,
201 &vxcan_link_ops, tbp, extack);
202 if (IS_ERR(peer)) {
203 put_net(peer_net);
204 return PTR_ERR(peer);
205 }
206
207 if (ifmp && dev->ifindex)
208 peer->ifindex = ifmp->ifi_index;
209
210 err = register_netdevice(peer);
211 put_net(peer_net);
212 peer_net = NULL;
213 if (err < 0) {
214 free_netdev(peer);
215 return err;
216 }
217
218 netif_carrier_off(peer);
219
220 err = rtnl_configure_link(peer, ifmp);
221 if (err < 0)
222 goto unregister_network_device;
223
224
225 if (tb[IFLA_IFNAME])
226 nla_strlcpy(dev->name, tb[IFLA_IFNAME], IFNAMSIZ);
227 else
228 snprintf(dev->name, IFNAMSIZ, DRV_NAME "%%d");
229
230 err = register_netdevice(dev);
231 if (err < 0)
232 goto unregister_network_device;
233
234 netif_carrier_off(dev);
235
236
237 priv = netdev_priv(dev);
238 rcu_assign_pointer(priv->peer, peer);
239
240 priv = netdev_priv(peer);
241 rcu_assign_pointer(priv->peer, dev);
242
243 return 0;
244
245unregister_network_device:
246 unregister_netdevice(peer);
247 return err;
248}
249
250static void vxcan_dellink(struct net_device *dev, struct list_head *head)
251{
252 struct vxcan_priv *priv;
253 struct net_device *peer;
254
255 priv = netdev_priv(dev);
256 peer = rtnl_dereference(priv->peer);
257
258
259
260
261
262 RCU_INIT_POINTER(priv->peer, NULL);
263 unregister_netdevice_queue(dev, head);
264
265 if (peer) {
266 priv = netdev_priv(peer);
267 RCU_INIT_POINTER(priv->peer, NULL);
268 unregister_netdevice_queue(peer, head);
269 }
270}
271
272static const struct nla_policy vxcan_policy[VXCAN_INFO_MAX + 1] = {
273 [VXCAN_INFO_PEER] = { .len = sizeof(struct ifinfomsg) },
274};
275
276static struct net *vxcan_get_link_net(const struct net_device *dev)
277{
278 struct vxcan_priv *priv = netdev_priv(dev);
279 struct net_device *peer = rtnl_dereference(priv->peer);
280
281 return peer ? dev_net(peer) : dev_net(dev);
282}
283
284static struct rtnl_link_ops vxcan_link_ops = {
285 .kind = DRV_NAME,
286 .priv_size = ALIGN(sizeof(struct vxcan_priv), NETDEV_ALIGN) + sizeof(struct can_ml_priv),
287 .setup = vxcan_setup,
288 .newlink = vxcan_newlink,
289 .dellink = vxcan_dellink,
290 .policy = vxcan_policy,
291 .maxtype = VXCAN_INFO_MAX,
292 .get_link_net = vxcan_get_link_net,
293};
294
295static __init int vxcan_init(void)
296{
297 pr_info("vxcan: Virtual CAN Tunnel driver\n");
298
299 return rtnl_link_register(&vxcan_link_ops);
300}
301
302static __exit void vxcan_exit(void)
303{
304 rtnl_link_unregister(&vxcan_link_ops);
305}
306
307module_init(vxcan_init);
308module_exit(vxcan_exit);
309
