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, len: 0, success: 0, multicast: 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(dev: 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(list: &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, rx_handler: tap_handle_frame, rx_handler_data: &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(tap: &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(dev: 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(info: 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(buf: tap_name, IFNAMSIZ, fmt: "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(major: macvtap_major, tap: &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(cls: &macvtap_class, parent: &dev->dev, devt,
177 drvdata: dev, fmt: "%s", tap_name);
178 if (IS_ERR(ptr: classdev)) {
179 tap_free_minor(major: macvtap_major, tap: &vlantap->tap);
180 return notifier_from_errno(err: PTR_ERR(ptr: classdev));
181 }
182 err = sysfs_create_link(kobj: &dev->dev.kobj, target: &classdev->kobj,
183 name: 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(kobj: &dev->dev.kobj, name: tap_name);
192 devt = MKDEV(MAJOR(macvtap_major), vlantap->tap.minor);
193 device_destroy(cls: &macvtap_class, devt);
194 tap_free_minor(major: macvtap_major, tap: &vlantap->tap);
195 break;
196 case NETDEV_CHANGE_TX_QUEUE_LEN:
197 if (tap_queue_resize(tap: &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(tap_cdev: &macvtap_cdev, tap_major: &macvtap_major, device_name: "macvtap",
214 THIS_MODULE);
215 if (err)
216 goto out1;
217
218 err = class_register(class: &macvtap_class);
219 if (err)
220 goto out2;
221
222 err = register_netdevice_notifier(nb: &macvtap_notifier_block);
223 if (err)
224 goto out3;
225
226 err = macvlan_link_register(ops: &macvtap_link_ops);
227 if (err)
228 goto out4;
229
230 return 0;
231
232out4:
233 unregister_netdevice_notifier(nb: &macvtap_notifier_block);
234out3:
235 class_unregister(class: &macvtap_class);
236out2:
237 tap_destroy_cdev(major: macvtap_major, tap_cdev: &macvtap_cdev);
238out1:
239 return err;
240}
241module_init(macvtap_init);
242
243static void __exit macvtap_exit(void)
244{
245 rtnl_link_unregister(ops: &macvtap_link_ops);
246 unregister_netdevice_notifier(nb: &macvtap_notifier_block);
247 class_unregister(class: &macvtap_class);
248 tap_destroy_cdev(major: macvtap_major, tap_cdev: &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

source code of linux/drivers/net/macvtap.c