1// SPDX-License-Identifier: GPL-2.0-only
2#include <linux/etherdevice.h>
3#include <linux/if_macvlan.h>
4#include <linux/if_tap.h>
5#include <linux/if_vlan.h>
6#include <linux/interrupt.h>
7#include <linux/nsproxy.h>
8#include <linux/compat.h>
9#include <linux/if_tun.h>
10#include <linux/module.h>
11#include <linux/skbuff.h>
12#include <linux/cache.h>
13#include <linux/sched/signal.h>
14#include <linux/types.h>
15#include <linux/slab.h>
16#include <linux/wait.h>
17#include <linux/cdev.h>
18#include <linux/idr.h>
19#include <linux/fs.h>
20#include <linux/uio.h>
21
22#include <net/net_namespace.h>
23#include <net/rtnetlink.h>
24#include <net/sock.h>
25#include <linux/virtio_net.h>
26#include <linux/skb_array.h>
27
28struct macvtap_dev {
29	struct macvlan_dev vlan;
30	struct tap_dev    tap;
31};
32
33/*
34 * Variables for dealing with macvtaps device numbers.
35 */
36static dev_t macvtap_major;
37
38static const void *macvtap_net_namespace(const struct device *d)
39{
40	const struct net_device *dev = to_net_dev(d->parent);
41	return dev_net(dev);
42}
43
44static struct class macvtap_class = {
45	.name = "macvtap",
46	.ns_type = &net_ns_type_operations,
47	.namespace = macvtap_net_namespace,
48};
49static struct cdev macvtap_cdev;
50
51#define TUN_OFFLOADS (NETIF_F_HW_CSUM | NETIF_F_TSO_ECN | NETIF_F_TSO | \
52		      NETIF_F_TSO6)
53
54static void macvtap_count_tx_dropped(struct tap_dev *tap)
55{
56	struct macvtap_dev *vlantap = container_of(tap, struct macvtap_dev, tap);
57	struct macvlan_dev *vlan = &vlantap->vlan;
58
59	this_cpu_inc(vlan->pcpu_stats->tx_dropped);
60}
61
62static void macvtap_count_rx_dropped(struct tap_dev *tap)
63{
64	struct macvtap_dev *vlantap = container_of(tap, struct macvtap_dev, tap);
65	struct macvlan_dev *vlan = &vlantap->vlan;
66
67	macvlan_count_rx(vlan, 0, 0, 0);
68}
69
70static void macvtap_update_features(struct tap_dev *tap,
71				    netdev_features_t features)
72{
73	struct macvtap_dev *vlantap = container_of(tap, struct macvtap_dev, tap);
74	struct macvlan_dev *vlan = &vlantap->vlan;
75
76	vlan->set_features = features;
77	netdev_update_features(vlan->dev);
78}
79
80static int macvtap_newlink(struct net *src_net, struct net_device *dev,
81			   struct nlattr *tb[], struct nlattr *data[],
82			   struct netlink_ext_ack *extack)
83{
84	struct macvtap_dev *vlantap = netdev_priv(dev);
85	int err;
86
87	INIT_LIST_HEAD(&vlantap->tap.queue_list);
88
89	/* Since macvlan supports all offloads by default, make
90	 * tap support all offloads also.
91	 */
92	vlantap->tap.tap_features = TUN_OFFLOADS;
93
94	/* Register callbacks for rx/tx drops accounting and updating
95	 * net_device features
96	 */
97	vlantap->tap.count_tx_dropped = macvtap_count_tx_dropped;
98	vlantap->tap.count_rx_dropped = macvtap_count_rx_dropped;
99	vlantap->tap.update_features  = macvtap_update_features;
100
101	err = netdev_rx_handler_register(dev, tap_handle_frame, &vlantap->tap);
102	if (err)
103		return err;
104
105	/* Don't put anything that may fail after macvlan_common_newlink
106	 * because we can't undo what it does.
107	 */
108	err = macvlan_common_newlink(src_net, dev, tb, data, extack);
109	if (err) {
110		netdev_rx_handler_unregister(dev);
111		return err;
112	}
113
114	vlantap->tap.dev = vlantap->vlan.dev;
115
116	return 0;
117}
118
119static void macvtap_dellink(struct net_device *dev,
120			    struct list_head *head)
121{
122	struct macvtap_dev *vlantap = netdev_priv(dev);
123
124	netdev_rx_handler_unregister(dev);
125	tap_del_queues(&vlantap->tap);
126	macvlan_dellink(dev, head);
127}
128
129static void macvtap_setup(struct net_device *dev)
130{
131	macvlan_common_setup(dev);
132	dev->tx_queue_len = TUN_READQ_SIZE;
133}
134
135static struct net *macvtap_link_net(const struct net_device *dev)
136{
137	return dev_net(macvlan_dev_real_dev(dev));
138}
139
140static struct rtnl_link_ops macvtap_link_ops __read_mostly = {
141	.kind		= "macvtap",
142	.setup		= macvtap_setup,
143	.newlink	= macvtap_newlink,
144	.dellink	= macvtap_dellink,
145	.get_link_net	= macvtap_link_net,
146	.priv_size      = sizeof(struct macvtap_dev),
147};
148
149static int macvtap_device_event(struct notifier_block *unused,
150				unsigned long event, void *ptr)
151{
152	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
153	struct macvtap_dev *vlantap;
154	struct device *classdev;
155	dev_t devt;
156	int err;
157	char tap_name[IFNAMSIZ];
158
159	if (dev->rtnl_link_ops != &macvtap_link_ops)
160		return NOTIFY_DONE;
161
162	snprintf(tap_name, IFNAMSIZ, "tap%d", dev->ifindex);
163	vlantap = netdev_priv(dev);
164
165	switch (event) {
166	case NETDEV_REGISTER:
167		/* Create the device node here after the network device has
168		 * been registered but before register_netdevice has
169		 * finished running.
170		 */
171		err = tap_get_minor(macvtap_major, &vlantap->tap);
172		if (err)
173			return notifier_from_errno(err);
174
175		devt = MKDEV(MAJOR(macvtap_major), vlantap->tap.minor);
176		classdev = device_create(&macvtap_class, &dev->dev, devt,
177					 dev, "%s", tap_name);
178		if (IS_ERR(classdev)) {
179			tap_free_minor(macvtap_major, &vlantap->tap);
180			return notifier_from_errno(PTR_ERR(classdev));
181		}
182		err = sysfs_create_link(&dev->dev.kobj, &classdev->kobj,
183					tap_name);
184		if (err)
185			return notifier_from_errno(err);
186		break;
187	case NETDEV_UNREGISTER:
188		/* vlan->minor == 0 if NETDEV_REGISTER above failed */
189		if (vlantap->tap.minor == 0)
190			break;
191		sysfs_remove_link(&dev->dev.kobj, tap_name);
192		devt = MKDEV(MAJOR(macvtap_major), vlantap->tap.minor);
193		device_destroy(&macvtap_class, devt);
194		tap_free_minor(macvtap_major, &vlantap->tap);
195		break;
196	case NETDEV_CHANGE_TX_QUEUE_LEN:
197		if (tap_queue_resize(&vlantap->tap))
198			return NOTIFY_BAD;
199		break;
200	}
201
202	return NOTIFY_DONE;
203}
204
205static struct notifier_block macvtap_notifier_block __read_mostly = {
206	.notifier_call	= macvtap_device_event,
207};
208
209static int __init macvtap_init(void)
210{
211	int err;
212
213	err = tap_create_cdev(&macvtap_cdev, &macvtap_major, "macvtap",
214			      THIS_MODULE);
215	if (err)
216		goto out1;
217
218	err = class_register(&macvtap_class);
219	if (err)
220		goto out2;
221
222	err = register_netdevice_notifier(&macvtap_notifier_block);
223	if (err)
224		goto out3;
225
226	err = macvlan_link_register(&macvtap_link_ops);
227	if (err)
228		goto out4;
229
230	return 0;
231
232out4:
233	unregister_netdevice_notifier(&macvtap_notifier_block);
234out3:
235	class_unregister(&macvtap_class);
236out2:
237	tap_destroy_cdev(macvtap_major, &macvtap_cdev);
238out1:
239	return err;
240}
241module_init(macvtap_init);
242
243static void __exit macvtap_exit(void)
244{
245	rtnl_link_unregister(&macvtap_link_ops);
246	unregister_netdevice_notifier(&macvtap_notifier_block);
247	class_unregister(&macvtap_class);
248	tap_destroy_cdev(macvtap_major, &macvtap_cdev);
249}
250module_exit(macvtap_exit);
251
252MODULE_ALIAS_RTNL_LINK("macvtap");
253MODULE_DESCRIPTION("MAC-VLAN based tap driver");
254MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
255MODULE_LICENSE("GPL");
256