xref: /openbmc/linux/drivers/net/macvtap.c (revision 10a03c36)
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 
28 struct macvtap_dev {
29 	struct macvlan_dev vlan;
30 	struct tap_dev    tap;
31 };
32 
33 /*
34  * Variables for dealing with macvtaps device numbers.
35  */
36 static dev_t macvtap_major;
37 
macvtap_net_namespace(const struct device * d)38 static 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 
44 static struct class macvtap_class = {
45 	.name = "macvtap",
46 	.ns_type = &net_ns_type_operations,
47 	.namespace = macvtap_net_namespace,
48 };
49 static 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 
macvtap_count_tx_dropped(struct tap_dev * tap)54 static 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 
macvtap_count_rx_dropped(struct tap_dev * tap)62 static 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 
macvtap_update_features(struct tap_dev * tap,netdev_features_t features)70 static 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 
macvtap_newlink(struct net * src_net,struct net_device * dev,struct nlattr * tb[],struct nlattr * data[],struct netlink_ext_ack * extack)80 static 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 
macvtap_dellink(struct net_device * dev,struct list_head * head)119 static 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 
macvtap_setup(struct net_device * dev)129 static void macvtap_setup(struct net_device *dev)
130 {
131 	macvlan_common_setup(dev);
132 	dev->tx_queue_len = TUN_READQ_SIZE;
133 }
134 
macvtap_link_net(const struct net_device * dev)135 static struct net *macvtap_link_net(const struct net_device *dev)
136 {
137 	return dev_net(macvlan_dev_real_dev(dev));
138 }
139 
140 static 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 
macvtap_device_event(struct notifier_block * unused,unsigned long event,void * ptr)149 static 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 
205 static struct notifier_block macvtap_notifier_block __read_mostly = {
206 	.notifier_call	= macvtap_device_event,
207 };
208 
macvtap_init(void)209 static 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 
232 out4:
233 	unregister_netdevice_notifier(&macvtap_notifier_block);
234 out3:
235 	class_unregister(&macvtap_class);
236 out2:
237 	tap_destroy_cdev(macvtap_major, &macvtap_cdev);
238 out1:
239 	return err;
240 }
241 module_init(macvtap_init);
242 
macvtap_exit(void)243 static 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 }
250 module_exit(macvtap_exit);
251 
252 MODULE_ALIAS_RTNL_LINK("macvtap");
253 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
254 MODULE_LICENSE("GPL");
255