1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * vxcan.c - Virtual CAN Tunnel for cross namespace communication
  4 *
  5 * This code is derived from drivers/net/can/vcan.c for the virtual CAN
  6 * specific parts and from drivers/net/veth.c to implement the netlink API
  7 * for network interface pairs in a common and established way.
  8 *
  9 * Copyright (c) 2017 Oliver Hartkopp <socketcan@hartkopp.net>
 10 */
 11
 12#include <linux/ethtool.h>
 13#include <linux/module.h>
 14#include <linux/init.h>
 15#include <linux/netdevice.h>
 16#include <linux/if_arp.h>
 17#include <linux/if_ether.h>
 18#include <linux/can.h>
 19#include <linux/can/dev.h>
 20#include <linux/can/skb.h>
 21#include <linux/can/vxcan.h>
 22#include <linux/can/can-ml.h>
 23#include <linux/slab.h>
 24#include <net/rtnetlink.h>
 25
 26#define DRV_NAME "vxcan"
 27
 28MODULE_DESCRIPTION("Virtual CAN Tunnel");
 29MODULE_LICENSE("GPL");
 30MODULE_AUTHOR("Oliver Hartkopp <socketcan@hartkopp.net>");
 31MODULE_ALIAS_RTNL_LINK(DRV_NAME);
 32
 33struct vxcan_priv {
 34	struct net_device __rcu	*peer;
 35};
 36
 37static netdev_tx_t vxcan_xmit(struct sk_buff *oskb, struct net_device *dev)
 38{
 39	struct vxcan_priv *priv = netdev_priv(dev);
 40	struct net_device *peer;
 
 41	struct net_device_stats *peerstats, *srcstats = &dev->stats;
 42	struct sk_buff *skb;
 43	unsigned int len;
 44
 45	if (can_dropped_invalid_skb(dev, oskb))
 46		return NETDEV_TX_OK;
 47
 48	rcu_read_lock();
 49	peer = rcu_dereference(priv->peer);
 50	if (unlikely(!peer)) {
 51		kfree_skb(oskb);
 52		dev->stats.tx_dropped++;
 53		goto out_unlock;
 54	}
 55
 56	skb_tx_timestamp(oskb);
 57
 58	skb = skb_clone(oskb, GFP_ATOMIC);
 59	if (skb) {
 60		consume_skb(oskb);
 61	} else {
 62		kfree_skb(oskb);
 63		goto out_unlock;
 64	}
 65
 66	/* reset CAN GW hop counter */
 67	skb->csum_start = 0;
 68	skb->pkt_type   = PACKET_BROADCAST;
 69	skb->dev        = peer;
 70	skb->ip_summed  = CHECKSUM_UNNECESSARY;
 71
 72	len = can_skb_get_data_len(skb);
 73	if (netif_rx(skb) == NET_RX_SUCCESS) {
 74		srcstats->tx_packets++;
 75		srcstats->tx_bytes += len;
 76		peerstats = &peer->stats;
 77		peerstats->rx_packets++;
 78		peerstats->rx_bytes += len;
 79	}
 80
 81out_unlock:
 82	rcu_read_unlock();
 83	return NETDEV_TX_OK;
 84}
 85
 86
 87static int vxcan_open(struct net_device *dev)
 88{
 89	struct vxcan_priv *priv = netdev_priv(dev);
 90	struct net_device *peer = rtnl_dereference(priv->peer);
 91
 92	if (!peer)
 93		return -ENOTCONN;
 94
 95	if (peer->flags & IFF_UP) {
 96		netif_carrier_on(dev);
 97		netif_carrier_on(peer);
 98	}
 99	return 0;
100}
101
102static int vxcan_close(struct net_device *dev)
103{
104	struct vxcan_priv *priv = netdev_priv(dev);
105	struct net_device *peer = rtnl_dereference(priv->peer);
106
107	netif_carrier_off(dev);
108	if (peer)
109		netif_carrier_off(peer);
110
111	return 0;
112}
113
114static int vxcan_get_iflink(const struct net_device *dev)
115{
116	struct vxcan_priv *priv = netdev_priv(dev);
117	struct net_device *peer;
118	int iflink;
119
120	rcu_read_lock();
121	peer = rcu_dereference(priv->peer);
122	iflink = peer ? peer->ifindex : 0;
123	rcu_read_unlock();
124
125	return iflink;
126}
127
128static int vxcan_change_mtu(struct net_device *dev, int new_mtu)
129{
130	/* Do not allow changing the MTU while running */
131	if (dev->flags & IFF_UP)
132		return -EBUSY;
133
134	if (new_mtu != CAN_MTU && new_mtu != CANFD_MTU &&
135	    !can_is_canxl_dev_mtu(new_mtu))
136		return -EINVAL;
137
138	dev->mtu = new_mtu;
139	return 0;
140}
141
142static const struct net_device_ops vxcan_netdev_ops = {
143	.ndo_open	= vxcan_open,
144	.ndo_stop	= vxcan_close,
145	.ndo_start_xmit	= vxcan_xmit,
146	.ndo_get_iflink	= vxcan_get_iflink,
147	.ndo_change_mtu = vxcan_change_mtu,
148};
149
150static const struct ethtool_ops vxcan_ethtool_ops = {
151	.get_ts_info = ethtool_op_get_ts_info,
152};
153
154static void vxcan_setup(struct net_device *dev)
155{
156	struct can_ml_priv *can_ml;
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	dev->netdev_ops		= &vxcan_netdev_ops;
165	dev->ethtool_ops	= &vxcan_ethtool_ops;
166	dev->needs_free_netdev	= true;
167
168	can_ml = netdev_priv(dev) + ALIGN(sizeof(struct vxcan_priv), NETDEV_ALIGN);
169	can_set_ml_priv(dev, can_ml);
170}
171
172/* forward declaration for rtnl_create_link() */
173static struct rtnl_link_ops vxcan_link_ops;
174
175static int vxcan_newlink(struct net *net, struct net_device *dev,
176			 struct nlattr *tb[], struct nlattr *data[],
177			 struct netlink_ext_ack *extack)
178{
179	struct vxcan_priv *priv;
180	struct net_device *peer;
181	struct net *peer_net;
182
183	struct nlattr *peer_tb[IFLA_MAX + 1], **tbp = tb;
184	char ifname[IFNAMSIZ];
185	unsigned char name_assign_type;
186	struct ifinfomsg *ifmp = NULL;
187	int err;
188
189	/* register peer device */
190	if (data && data[VXCAN_INFO_PEER]) {
191		struct nlattr *nla_peer;
192
193		nla_peer = data[VXCAN_INFO_PEER];
194		ifmp = nla_data(nla_peer);
195		err = rtnl_nla_parse_ifinfomsg(peer_tb, nla_peer, extack);
 
 
 
 
 
196		if (err < 0)
197			return err;
198
199		tbp = peer_tb;
200	}
201
202	if (ifmp && tbp[IFLA_IFNAME]) {
203		nla_strscpy(ifname, tbp[IFLA_IFNAME], IFNAMSIZ);
204		name_assign_type = NET_NAME_USER;
205	} else {
206		snprintf(ifname, IFNAMSIZ, DRV_NAME "%%d");
207		name_assign_type = NET_NAME_ENUM;
208	}
209
210	peer_net = rtnl_link_get_net(net, tbp);
211	if (IS_ERR(peer_net))
212		return PTR_ERR(peer_net);
213
214	peer = rtnl_create_link(peer_net, ifname, name_assign_type,
215				&vxcan_link_ops, tbp, extack);
216	if (IS_ERR(peer)) {
217		put_net(peer_net);
218		return PTR_ERR(peer);
219	}
220
221	if (ifmp && dev->ifindex)
222		peer->ifindex = ifmp->ifi_index;
223
224	err = register_netdevice(peer);
225	put_net(peer_net);
226	peer_net = NULL;
227	if (err < 0) {
228		free_netdev(peer);
229		return err;
230	}
231
232	netif_carrier_off(peer);
233
234	err = rtnl_configure_link(peer, ifmp, 0, NULL);
235	if (err < 0)
236		goto unregister_network_device;
237
238	/* register first device */
239	if (tb[IFLA_IFNAME])
240		nla_strscpy(dev->name, tb[IFLA_IFNAME], IFNAMSIZ);
241	else
242		snprintf(dev->name, IFNAMSIZ, DRV_NAME "%%d");
243
244	err = register_netdevice(dev);
245	if (err < 0)
246		goto unregister_network_device;
247
248	netif_carrier_off(dev);
249
250	/* cross link the device pair */
251	priv = netdev_priv(dev);
252	rcu_assign_pointer(priv->peer, peer);
253
254	priv = netdev_priv(peer);
255	rcu_assign_pointer(priv->peer, dev);
256
257	return 0;
258
259unregister_network_device:
260	unregister_netdevice(peer);
261	return err;
262}
263
264static void vxcan_dellink(struct net_device *dev, struct list_head *head)
265{
266	struct vxcan_priv *priv;
267	struct net_device *peer;
268
269	priv = netdev_priv(dev);
270	peer = rtnl_dereference(priv->peer);
271
272	/* Note : dellink() is called from default_device_exit_batch(),
273	 * before a rcu_synchronize() point. The devices are guaranteed
274	 * not being freed before one RCU grace period.
275	 */
276	RCU_INIT_POINTER(priv->peer, NULL);
277	unregister_netdevice_queue(dev, head);
278
279	if (peer) {
280		priv = netdev_priv(peer);
281		RCU_INIT_POINTER(priv->peer, NULL);
282		unregister_netdevice_queue(peer, head);
283	}
284}
285
286static const struct nla_policy vxcan_policy[VXCAN_INFO_MAX + 1] = {
287	[VXCAN_INFO_PEER] = { .len = sizeof(struct ifinfomsg) },
288};
289
290static struct net *vxcan_get_link_net(const struct net_device *dev)
291{
292	struct vxcan_priv *priv = netdev_priv(dev);
293	struct net_device *peer = rtnl_dereference(priv->peer);
294
295	return peer ? dev_net(peer) : dev_net(dev);
296}
297
298static struct rtnl_link_ops vxcan_link_ops = {
299	.kind		= DRV_NAME,
300	.priv_size	= ALIGN(sizeof(struct vxcan_priv), NETDEV_ALIGN) + sizeof(struct can_ml_priv),
301	.setup		= vxcan_setup,
302	.newlink	= vxcan_newlink,
303	.dellink	= vxcan_dellink,
304	.policy		= vxcan_policy,
305	.maxtype	= VXCAN_INFO_MAX,
306	.get_link_net	= vxcan_get_link_net,
307};
308
309static __init int vxcan_init(void)
310{
311	pr_info("vxcan: Virtual CAN Tunnel driver\n");
312
313	return rtnl_link_register(&vxcan_link_ops);
314}
315
316static __exit void vxcan_exit(void)
317{
318	rtnl_link_unregister(&vxcan_link_ops);
319}
320
321module_init(vxcan_init);
322module_exit(vxcan_exit);

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * vxcan.c - Virtual CAN Tunnel for cross namespace communication
  4 *
  5 * This code is derived from drivers/net/can/vcan.c for the virtual CAN
  6 * specific parts and from drivers/net/veth.c to implement the netlink API
  7 * for network interface pairs in a common and established way.
  8 *
  9 * Copyright (c) 2017 Oliver Hartkopp <socketcan@hartkopp.net>
 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	/* reset CAN GW hop counter */
 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	/* Do not allow changing the MTU while running */
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/* forward declaration for rtnl_create_link() */
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	/* register peer device */
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	/* register first device */
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	/* cross link the device pair */
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	/* Note : dellink() is called from default_device_exit_batch(),
259	 * before a rcu_synchronize() point. The devices are guaranteed
260	 * not being freed before one RCU grace period.
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);