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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");
1#include <linux/etherdevice.h>
2#include <linux/if_macvlan.h>
3#include <linux/if_vlan.h>
4#include <linux/interrupt.h>
5#include <linux/nsproxy.h>
6#include <linux/compat.h>
7#include <linux/if_tun.h>
8#include <linux/module.h>
9#include <linux/skbuff.h>
10#include <linux/cache.h>
11#include <linux/sched.h>
12#include <linux/types.h>
13#include <linux/slab.h>
14#include <linux/init.h>
15#include <linux/wait.h>
16#include <linux/cdev.h>
17#include <linux/idr.h>
18#include <linux/fs.h>
19
20#include <net/net_namespace.h>
21#include <net/rtnetlink.h>
22#include <net/sock.h>
23#include <linux/virtio_net.h>
24
25/*
26 * A macvtap queue is the central object of this driver, it connects
27 * an open character device to a macvlan interface. There can be
28 * multiple queues on one interface, which map back to queues
29 * implemented in hardware on the underlying device.
30 *
31 * macvtap_proto is used to allocate queues through the sock allocation
32 * mechanism.
33 *
34 * TODO: multiqueue support is currently not implemented, even though
35 * macvtap is basically prepared for that. We will need to add this
36 * here as well as in virtio-net and qemu to get line rate on 10gbit
37 * adapters from a guest.
38 */
39struct macvtap_queue {
40 struct sock sk;
41 struct socket sock;
42 struct socket_wq wq;
43 int vnet_hdr_sz;
44 struct macvlan_dev __rcu *vlan;
45 struct file *file;
46 unsigned int flags;
47};
48
49static struct proto macvtap_proto = {
50 .name = "macvtap",
51 .owner = THIS_MODULE,
52 .obj_size = sizeof (struct macvtap_queue),
53};
54
55/*
56 * Variables for dealing with macvtaps device numbers.
57 */
58static dev_t macvtap_major;
59#define MACVTAP_NUM_DEVS (1U << MINORBITS)
60static DEFINE_MUTEX(minor_lock);
61static DEFINE_IDR(minor_idr);
62
63#define GOODCOPY_LEN 128
64static struct class *macvtap_class;
65static struct cdev macvtap_cdev;
66
67static const struct proto_ops macvtap_socket_ops;
68
69/*
70 * RCU usage:
71 * The macvtap_queue and the macvlan_dev are loosely coupled, the
72 * pointers from one to the other can only be read while rcu_read_lock
73 * or macvtap_lock is held.
74 *
75 * Both the file and the macvlan_dev hold a reference on the macvtap_queue
76 * through sock_hold(&q->sk). When the macvlan_dev goes away first,
77 * q->vlan becomes inaccessible. When the files gets closed,
78 * macvtap_get_queue() fails.
79 *
80 * There may still be references to the struct sock inside of the
81 * queue from outbound SKBs, but these never reference back to the
82 * file or the dev. The data structure is freed through __sk_free
83 * when both our references and any pending SKBs are gone.
84 */
85static DEFINE_SPINLOCK(macvtap_lock);
86
87/*
88 * get_slot: return a [unused/occupied] slot in vlan->taps[]:
89 * - if 'q' is NULL, return the first empty slot;
90 * - otherwise, return the slot this pointer occupies.
91 */
92static int get_slot(struct macvlan_dev *vlan, struct macvtap_queue *q)
93{
94 int i;
95
96 for (i = 0; i < MAX_MACVTAP_QUEUES; i++) {
97 if (rcu_dereference(vlan->taps[i]) == q)
98 return i;
99 }
100
101 /* Should never happen */
102 BUG_ON(1);
103}
104
105static int macvtap_set_queue(struct net_device *dev, struct file *file,
106 struct macvtap_queue *q)
107{
108 struct macvlan_dev *vlan = netdev_priv(dev);
109 int index;
110 int err = -EBUSY;
111
112 spin_lock(&macvtap_lock);
113 if (vlan->numvtaps == MAX_MACVTAP_QUEUES)
114 goto out;
115
116 err = 0;
117 index = get_slot(vlan, NULL);
118 rcu_assign_pointer(q->vlan, vlan);
119 rcu_assign_pointer(vlan->taps[index], q);
120 sock_hold(&q->sk);
121
122 q->file = file;
123 file->private_data = q;
124
125 vlan->numvtaps++;
126
127out:
128 spin_unlock(&macvtap_lock);
129 return err;
130}
131
132/*
133 * The file owning the queue got closed, give up both
134 * the reference that the files holds as well as the
135 * one from the macvlan_dev if that still exists.
136 *
137 * Using the spinlock makes sure that we don't get
138 * to the queue again after destroying it.
139 */
140static void macvtap_put_queue(struct macvtap_queue *q)
141{
142 struct macvlan_dev *vlan;
143
144 spin_lock(&macvtap_lock);
145 vlan = rcu_dereference_protected(q->vlan,
146 lockdep_is_held(&macvtap_lock));
147 if (vlan) {
148 int index = get_slot(vlan, q);
149
150 RCU_INIT_POINTER(vlan->taps[index], NULL);
151 RCU_INIT_POINTER(q->vlan, NULL);
152 sock_put(&q->sk);
153 --vlan->numvtaps;
154 }
155
156 spin_unlock(&macvtap_lock);
157
158 synchronize_rcu();
159 sock_put(&q->sk);
160}
161
162/*
163 * Select a queue based on the rxq of the device on which this packet
164 * arrived. If the incoming device is not mq, calculate a flow hash
165 * to select a queue. If all fails, find the first available queue.
166 * Cache vlan->numvtaps since it can become zero during the execution
167 * of this function.
168 */
169static struct macvtap_queue *macvtap_get_queue(struct net_device *dev,
170 struct sk_buff *skb)
171{
172 struct macvlan_dev *vlan = netdev_priv(dev);
173 struct macvtap_queue *tap = NULL;
174 int numvtaps = vlan->numvtaps;
175 __u32 rxq;
176
177 if (!numvtaps)
178 goto out;
179
180 /* Check if we can use flow to select a queue */
181 rxq = skb_get_rxhash(skb);
182 if (rxq) {
183 tap = rcu_dereference(vlan->taps[rxq % numvtaps]);
184 if (tap)
185 goto out;
186 }
187
188 if (likely(skb_rx_queue_recorded(skb))) {
189 rxq = skb_get_rx_queue(skb);
190
191 while (unlikely(rxq >= numvtaps))
192 rxq -= numvtaps;
193
194 tap = rcu_dereference(vlan->taps[rxq]);
195 if (tap)
196 goto out;
197 }
198
199 /* Everything failed - find first available queue */
200 for (rxq = 0; rxq < MAX_MACVTAP_QUEUES; rxq++) {
201 tap = rcu_dereference(vlan->taps[rxq]);
202 if (tap)
203 break;
204 }
205
206out:
207 return tap;
208}
209
210/*
211 * The net_device is going away, give up the reference
212 * that it holds on all queues and safely set the pointer
213 * from the queues to NULL.
214 */
215static void macvtap_del_queues(struct net_device *dev)
216{
217 struct macvlan_dev *vlan = netdev_priv(dev);
218 struct macvtap_queue *q, *qlist[MAX_MACVTAP_QUEUES];
219 int i, j = 0;
220
221 /* macvtap_put_queue can free some slots, so go through all slots */
222 spin_lock(&macvtap_lock);
223 for (i = 0; i < MAX_MACVTAP_QUEUES && vlan->numvtaps; i++) {
224 q = rcu_dereference_protected(vlan->taps[i],
225 lockdep_is_held(&macvtap_lock));
226 if (q) {
227 qlist[j++] = q;
228 RCU_INIT_POINTER(vlan->taps[i], NULL);
229 RCU_INIT_POINTER(q->vlan, NULL);
230 vlan->numvtaps--;
231 }
232 }
233 BUG_ON(vlan->numvtaps != 0);
234 /* guarantee that any future macvtap_set_queue will fail */
235 vlan->numvtaps = MAX_MACVTAP_QUEUES;
236 spin_unlock(&macvtap_lock);
237
238 synchronize_rcu();
239
240 for (--j; j >= 0; j--)
241 sock_put(&qlist[j]->sk);
242}
243
244/*
245 * Forward happens for data that gets sent from one macvlan
246 * endpoint to another one in bridge mode. We just take
247 * the skb and put it into the receive queue.
248 */
249static int macvtap_forward(struct net_device *dev, struct sk_buff *skb)
250{
251 struct macvtap_queue *q = macvtap_get_queue(dev, skb);
252 if (!q)
253 goto drop;
254
255 if (skb_queue_len(&q->sk.sk_receive_queue) >= dev->tx_queue_len)
256 goto drop;
257
258 skb_queue_tail(&q->sk.sk_receive_queue, skb);
259 wake_up_interruptible_poll(sk_sleep(&q->sk), POLLIN | POLLRDNORM | POLLRDBAND);
260 return NET_RX_SUCCESS;
261
262drop:
263 kfree_skb(skb);
264 return NET_RX_DROP;
265}
266
267/*
268 * Receive is for data from the external interface (lowerdev),
269 * in case of macvtap, we can treat that the same way as
270 * forward, which macvlan cannot.
271 */
272static int macvtap_receive(struct sk_buff *skb)
273{
274 skb_push(skb, ETH_HLEN);
275 return macvtap_forward(skb->dev, skb);
276}
277
278static int macvtap_get_minor(struct macvlan_dev *vlan)
279{
280 int retval = -ENOMEM;
281 int id;
282
283 mutex_lock(&minor_lock);
284 if (idr_pre_get(&minor_idr, GFP_KERNEL) == 0)
285 goto exit;
286
287 retval = idr_get_new_above(&minor_idr, vlan, 1, &id);
288 if (retval < 0) {
289 if (retval == -EAGAIN)
290 retval = -ENOMEM;
291 goto exit;
292 }
293 if (id < MACVTAP_NUM_DEVS) {
294 vlan->minor = id;
295 } else {
296 printk(KERN_ERR "too many macvtap devices\n");
297 retval = -EINVAL;
298 idr_remove(&minor_idr, id);
299 }
300exit:
301 mutex_unlock(&minor_lock);
302 return retval;
303}
304
305static void macvtap_free_minor(struct macvlan_dev *vlan)
306{
307 mutex_lock(&minor_lock);
308 if (vlan->minor) {
309 idr_remove(&minor_idr, vlan->minor);
310 vlan->minor = 0;
311 }
312 mutex_unlock(&minor_lock);
313}
314
315static struct net_device *dev_get_by_macvtap_minor(int minor)
316{
317 struct net_device *dev = NULL;
318 struct macvlan_dev *vlan;
319
320 mutex_lock(&minor_lock);
321 vlan = idr_find(&minor_idr, minor);
322 if (vlan) {
323 dev = vlan->dev;
324 dev_hold(dev);
325 }
326 mutex_unlock(&minor_lock);
327 return dev;
328}
329
330static int macvtap_newlink(struct net *src_net,
331 struct net_device *dev,
332 struct nlattr *tb[],
333 struct nlattr *data[])
334{
335 /* Don't put anything that may fail after macvlan_common_newlink
336 * because we can't undo what it does.
337 */
338 return macvlan_common_newlink(src_net, dev, tb, data,
339 macvtap_receive, macvtap_forward);
340}
341
342static void macvtap_dellink(struct net_device *dev,
343 struct list_head *head)
344{
345 macvtap_del_queues(dev);
346 macvlan_dellink(dev, head);
347}
348
349static void macvtap_setup(struct net_device *dev)
350{
351 macvlan_common_setup(dev);
352 dev->tx_queue_len = TUN_READQ_SIZE;
353}
354
355static struct rtnl_link_ops macvtap_link_ops __read_mostly = {
356 .kind = "macvtap",
357 .setup = macvtap_setup,
358 .newlink = macvtap_newlink,
359 .dellink = macvtap_dellink,
360};
361
362
363static void macvtap_sock_write_space(struct sock *sk)
364{
365 wait_queue_head_t *wqueue;
366
367 if (!sock_writeable(sk) ||
368 !test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
369 return;
370
371 wqueue = sk_sleep(sk);
372 if (wqueue && waitqueue_active(wqueue))
373 wake_up_interruptible_poll(wqueue, POLLOUT | POLLWRNORM | POLLWRBAND);
374}
375
376static void macvtap_sock_destruct(struct sock *sk)
377{
378 skb_queue_purge(&sk->sk_receive_queue);
379}
380
381static int macvtap_open(struct inode *inode, struct file *file)
382{
383 struct net *net = current->nsproxy->net_ns;
384 struct net_device *dev = dev_get_by_macvtap_minor(iminor(inode));
385 struct macvtap_queue *q;
386 int err;
387
388 err = -ENODEV;
389 if (!dev)
390 goto out;
391
392 err = -ENOMEM;
393 q = (struct macvtap_queue *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
394 &macvtap_proto);
395 if (!q)
396 goto out;
397
398 q->sock.wq = &q->wq;
399 init_waitqueue_head(&q->wq.wait);
400 q->sock.type = SOCK_RAW;
401 q->sock.state = SS_CONNECTED;
402 q->sock.file = file;
403 q->sock.ops = &macvtap_socket_ops;
404 sock_init_data(&q->sock, &q->sk);
405 q->sk.sk_write_space = macvtap_sock_write_space;
406 q->sk.sk_destruct = macvtap_sock_destruct;
407 q->flags = IFF_VNET_HDR | IFF_NO_PI | IFF_TAP;
408 q->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
409
410 /*
411 * so far only KVM virtio_net uses macvtap, enable zero copy between
412 * guest kernel and host kernel when lower device supports zerocopy
413 *
414 * The macvlan supports zerocopy iff the lower device supports zero
415 * copy so we don't have to look at the lower device directly.
416 */
417 if ((dev->features & NETIF_F_HIGHDMA) && (dev->features & NETIF_F_SG))
418 sock_set_flag(&q->sk, SOCK_ZEROCOPY);
419
420 err = macvtap_set_queue(dev, file, q);
421 if (err)
422 sock_put(&q->sk);
423
424out:
425 if (dev)
426 dev_put(dev);
427
428 return err;
429}
430
431static int macvtap_release(struct inode *inode, struct file *file)
432{
433 struct macvtap_queue *q = file->private_data;
434 macvtap_put_queue(q);
435 return 0;
436}
437
438static unsigned int macvtap_poll(struct file *file, poll_table * wait)
439{
440 struct macvtap_queue *q = file->private_data;
441 unsigned int mask = POLLERR;
442
443 if (!q)
444 goto out;
445
446 mask = 0;
447 poll_wait(file, &q->wq.wait, wait);
448
449 if (!skb_queue_empty(&q->sk.sk_receive_queue))
450 mask |= POLLIN | POLLRDNORM;
451
452 if (sock_writeable(&q->sk) ||
453 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &q->sock.flags) &&
454 sock_writeable(&q->sk)))
455 mask |= POLLOUT | POLLWRNORM;
456
457out:
458 return mask;
459}
460
461static inline struct sk_buff *macvtap_alloc_skb(struct sock *sk, size_t prepad,
462 size_t len, size_t linear,
463 int noblock, int *err)
464{
465 struct sk_buff *skb;
466
467 /* Under a page? Don't bother with paged skb. */
468 if (prepad + len < PAGE_SIZE || !linear)
469 linear = len;
470
471 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
472 err);
473 if (!skb)
474 return NULL;
475
476 skb_reserve(skb, prepad);
477 skb_put(skb, linear);
478 skb->data_len = len - linear;
479 skb->len += len - linear;
480
481 return skb;
482}
483
484/* set skb frags from iovec, this can move to core network code for reuse */
485static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from,
486 int offset, size_t count)
487{
488 int len = iov_length(from, count) - offset;
489 int copy = skb_headlen(skb);
490 int size, offset1 = 0;
491 int i = 0;
492
493 /* Skip over from offset */
494 while (count && (offset >= from->iov_len)) {
495 offset -= from->iov_len;
496 ++from;
497 --count;
498 }
499
500 /* copy up to skb headlen */
501 while (count && (copy > 0)) {
502 size = min_t(unsigned int, copy, from->iov_len - offset);
503 if (copy_from_user(skb->data + offset1, from->iov_base + offset,
504 size))
505 return -EFAULT;
506 if (copy > size) {
507 ++from;
508 --count;
509 offset = 0;
510 } else
511 offset += size;
512 copy -= size;
513 offset1 += size;
514 }
515
516 if (len == offset1)
517 return 0;
518
519 while (count--) {
520 struct page *page[MAX_SKB_FRAGS];
521 int num_pages;
522 unsigned long base;
523 unsigned long truesize;
524
525 len = from->iov_len - offset;
526 if (!len) {
527 offset = 0;
528 ++from;
529 continue;
530 }
531 base = (unsigned long)from->iov_base + offset;
532 size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT;
533 if (i + size > MAX_SKB_FRAGS)
534 return -EMSGSIZE;
535 num_pages = get_user_pages_fast(base, size, 0, &page[i]);
536 if (num_pages != size) {
537 for (i = 0; i < num_pages; i++)
538 put_page(page[i]);
539 return -EFAULT;
540 }
541 truesize = size * PAGE_SIZE;
542 skb->data_len += len;
543 skb->len += len;
544 skb->truesize += truesize;
545 atomic_add(truesize, &skb->sk->sk_wmem_alloc);
546 while (len) {
547 int off = base & ~PAGE_MASK;
548 int size = min_t(int, len, PAGE_SIZE - off);
549 __skb_fill_page_desc(skb, i, page[i], off, size);
550 skb_shinfo(skb)->nr_frags++;
551 /* increase sk_wmem_alloc */
552 base += size;
553 len -= size;
554 i++;
555 }
556 offset = 0;
557 ++from;
558 }
559 return 0;
560}
561
562/*
563 * macvtap_skb_from_vnet_hdr and macvtap_skb_to_vnet_hdr should
564 * be shared with the tun/tap driver.
565 */
566static int macvtap_skb_from_vnet_hdr(struct sk_buff *skb,
567 struct virtio_net_hdr *vnet_hdr)
568{
569 unsigned short gso_type = 0;
570 if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
571 switch (vnet_hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
572 case VIRTIO_NET_HDR_GSO_TCPV4:
573 gso_type = SKB_GSO_TCPV4;
574 break;
575 case VIRTIO_NET_HDR_GSO_TCPV6:
576 gso_type = SKB_GSO_TCPV6;
577 break;
578 case VIRTIO_NET_HDR_GSO_UDP:
579 gso_type = SKB_GSO_UDP;
580 break;
581 default:
582 return -EINVAL;
583 }
584
585 if (vnet_hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
586 gso_type |= SKB_GSO_TCP_ECN;
587
588 if (vnet_hdr->gso_size == 0)
589 return -EINVAL;
590 }
591
592 if (vnet_hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
593 if (!skb_partial_csum_set(skb, vnet_hdr->csum_start,
594 vnet_hdr->csum_offset))
595 return -EINVAL;
596 }
597
598 if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
599 skb_shinfo(skb)->gso_size = vnet_hdr->gso_size;
600 skb_shinfo(skb)->gso_type = gso_type;
601
602 /* Header must be checked, and gso_segs computed. */
603 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
604 skb_shinfo(skb)->gso_segs = 0;
605 }
606 return 0;
607}
608
609static int macvtap_skb_to_vnet_hdr(const struct sk_buff *skb,
610 struct virtio_net_hdr *vnet_hdr)
611{
612 memset(vnet_hdr, 0, sizeof(*vnet_hdr));
613
614 if (skb_is_gso(skb)) {
615 struct skb_shared_info *sinfo = skb_shinfo(skb);
616
617 /* This is a hint as to how much should be linear. */
618 vnet_hdr->hdr_len = skb_headlen(skb);
619 vnet_hdr->gso_size = sinfo->gso_size;
620 if (sinfo->gso_type & SKB_GSO_TCPV4)
621 vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
622 else if (sinfo->gso_type & SKB_GSO_TCPV6)
623 vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
624 else if (sinfo->gso_type & SKB_GSO_UDP)
625 vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
626 else
627 BUG();
628 if (sinfo->gso_type & SKB_GSO_TCP_ECN)
629 vnet_hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
630 } else
631 vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
632
633 if (skb->ip_summed == CHECKSUM_PARTIAL) {
634 vnet_hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
635 vnet_hdr->csum_start = skb_checksum_start_offset(skb);
636 vnet_hdr->csum_offset = skb->csum_offset;
637 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
638 vnet_hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID;
639 } /* else everything is zero */
640
641 return 0;
642}
643
644
645/* Get packet from user space buffer */
646static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
647 const struct iovec *iv, unsigned long total_len,
648 size_t count, int noblock)
649{
650 struct sk_buff *skb;
651 struct macvlan_dev *vlan;
652 unsigned long len = total_len;
653 int err;
654 struct virtio_net_hdr vnet_hdr = { 0 };
655 int vnet_hdr_len = 0;
656 int copylen = 0;
657 bool zerocopy = false;
658
659 if (q->flags & IFF_VNET_HDR) {
660 vnet_hdr_len = q->vnet_hdr_sz;
661
662 err = -EINVAL;
663 if (len < vnet_hdr_len)
664 goto err;
665 len -= vnet_hdr_len;
666
667 err = memcpy_fromiovecend((void *)&vnet_hdr, iv, 0,
668 sizeof(vnet_hdr));
669 if (err < 0)
670 goto err;
671 if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
672 vnet_hdr.csum_start + vnet_hdr.csum_offset + 2 >
673 vnet_hdr.hdr_len)
674 vnet_hdr.hdr_len = vnet_hdr.csum_start +
675 vnet_hdr.csum_offset + 2;
676 err = -EINVAL;
677 if (vnet_hdr.hdr_len > len)
678 goto err;
679 }
680
681 err = -EINVAL;
682 if (unlikely(len < ETH_HLEN))
683 goto err;
684
685 err = -EMSGSIZE;
686 if (unlikely(count > UIO_MAXIOV))
687 goto err;
688
689 if (m && m->msg_control && sock_flag(&q->sk, SOCK_ZEROCOPY))
690 zerocopy = true;
691
692 if (zerocopy) {
693 /* Userspace may produce vectors with count greater than
694 * MAX_SKB_FRAGS, so we need to linearize parts of the skb
695 * to let the rest of data to be fit in the frags.
696 */
697 if (count > MAX_SKB_FRAGS) {
698 copylen = iov_length(iv, count - MAX_SKB_FRAGS);
699 if (copylen < vnet_hdr_len)
700 copylen = 0;
701 else
702 copylen -= vnet_hdr_len;
703 }
704 /* There are 256 bytes to be copied in skb, so there is enough
705 * room for skb expand head in case it is used.
706 * The rest buffer is mapped from userspace.
707 */
708 if (copylen < vnet_hdr.hdr_len)
709 copylen = vnet_hdr.hdr_len;
710 if (!copylen)
711 copylen = GOODCOPY_LEN;
712 } else
713 copylen = len;
714
715 skb = macvtap_alloc_skb(&q->sk, NET_IP_ALIGN, copylen,
716 vnet_hdr.hdr_len, noblock, &err);
717 if (!skb)
718 goto err;
719
720 if (zerocopy)
721 err = zerocopy_sg_from_iovec(skb, iv, vnet_hdr_len, count);
722 else
723 err = skb_copy_datagram_from_iovec(skb, 0, iv, vnet_hdr_len,
724 len);
725 if (err)
726 goto err_kfree;
727
728 skb_set_network_header(skb, ETH_HLEN);
729 skb_reset_mac_header(skb);
730 skb->protocol = eth_hdr(skb)->h_proto;
731
732 if (vnet_hdr_len) {
733 err = macvtap_skb_from_vnet_hdr(skb, &vnet_hdr);
734 if (err)
735 goto err_kfree;
736 }
737
738 rcu_read_lock_bh();
739 vlan = rcu_dereference_bh(q->vlan);
740 /* copy skb_ubuf_info for callback when skb has no error */
741 if (zerocopy) {
742 skb_shinfo(skb)->destructor_arg = m->msg_control;
743 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
744 }
745 if (vlan)
746 macvlan_start_xmit(skb, vlan->dev);
747 else
748 kfree_skb(skb);
749 rcu_read_unlock_bh();
750
751 return total_len;
752
753err_kfree:
754 kfree_skb(skb);
755
756err:
757 rcu_read_lock_bh();
758 vlan = rcu_dereference_bh(q->vlan);
759 if (vlan)
760 vlan->dev->stats.tx_dropped++;
761 rcu_read_unlock_bh();
762
763 return err;
764}
765
766static ssize_t macvtap_aio_write(struct kiocb *iocb, const struct iovec *iv,
767 unsigned long count, loff_t pos)
768{
769 struct file *file = iocb->ki_filp;
770 ssize_t result = -ENOLINK;
771 struct macvtap_queue *q = file->private_data;
772
773 result = macvtap_get_user(q, NULL, iv, iov_length(iv, count), count,
774 file->f_flags & O_NONBLOCK);
775 return result;
776}
777
778/* Put packet to the user space buffer */
779static ssize_t macvtap_put_user(struct macvtap_queue *q,
780 const struct sk_buff *skb,
781 const struct iovec *iv, int len)
782{
783 struct macvlan_dev *vlan;
784 int ret;
785 int vnet_hdr_len = 0;
786 int vlan_offset = 0;
787 int copied;
788
789 if (q->flags & IFF_VNET_HDR) {
790 struct virtio_net_hdr vnet_hdr;
791 vnet_hdr_len = q->vnet_hdr_sz;
792 if ((len -= vnet_hdr_len) < 0)
793 return -EINVAL;
794
795 ret = macvtap_skb_to_vnet_hdr(skb, &vnet_hdr);
796 if (ret)
797 return ret;
798
799 if (memcpy_toiovecend(iv, (void *)&vnet_hdr, 0, sizeof(vnet_hdr)))
800 return -EFAULT;
801 }
802 copied = vnet_hdr_len;
803
804 if (!vlan_tx_tag_present(skb))
805 len = min_t(int, skb->len, len);
806 else {
807 int copy;
808 struct {
809 __be16 h_vlan_proto;
810 __be16 h_vlan_TCI;
811 } veth;
812 veth.h_vlan_proto = htons(ETH_P_8021Q);
813 veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb));
814
815 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
816 len = min_t(int, skb->len + VLAN_HLEN, len);
817
818 copy = min_t(int, vlan_offset, len);
819 ret = skb_copy_datagram_const_iovec(skb, 0, iv, copied, copy);
820 len -= copy;
821 copied += copy;
822 if (ret || !len)
823 goto done;
824
825 copy = min_t(int, sizeof(veth), len);
826 ret = memcpy_toiovecend(iv, (void *)&veth, copied, copy);
827 len -= copy;
828 copied += copy;
829 if (ret || !len)
830 goto done;
831 }
832
833 ret = skb_copy_datagram_const_iovec(skb, vlan_offset, iv, copied, len);
834 copied += len;
835
836done:
837 rcu_read_lock_bh();
838 vlan = rcu_dereference_bh(q->vlan);
839 if (vlan)
840 macvlan_count_rx(vlan, copied - vnet_hdr_len, ret == 0, 0);
841 rcu_read_unlock_bh();
842
843 return ret ? ret : copied;
844}
845
846static ssize_t macvtap_do_read(struct macvtap_queue *q, struct kiocb *iocb,
847 const struct iovec *iv, unsigned long len,
848 int noblock)
849{
850 DECLARE_WAITQUEUE(wait, current);
851 struct sk_buff *skb;
852 ssize_t ret = 0;
853
854 add_wait_queue(sk_sleep(&q->sk), &wait);
855 while (len) {
856 current->state = TASK_INTERRUPTIBLE;
857
858 /* Read frames from the queue */
859 skb = skb_dequeue(&q->sk.sk_receive_queue);
860 if (!skb) {
861 if (noblock) {
862 ret = -EAGAIN;
863 break;
864 }
865 if (signal_pending(current)) {
866 ret = -ERESTARTSYS;
867 break;
868 }
869 /* Nothing to read, let's sleep */
870 schedule();
871 continue;
872 }
873 ret = macvtap_put_user(q, skb, iv, len);
874 kfree_skb(skb);
875 break;
876 }
877
878 current->state = TASK_RUNNING;
879 remove_wait_queue(sk_sleep(&q->sk), &wait);
880 return ret;
881}
882
883static ssize_t macvtap_aio_read(struct kiocb *iocb, const struct iovec *iv,
884 unsigned long count, loff_t pos)
885{
886 struct file *file = iocb->ki_filp;
887 struct macvtap_queue *q = file->private_data;
888 ssize_t len, ret = 0;
889
890 len = iov_length(iv, count);
891 if (len < 0) {
892 ret = -EINVAL;
893 goto out;
894 }
895
896 ret = macvtap_do_read(q, iocb, iv, len, file->f_flags & O_NONBLOCK);
897 ret = min_t(ssize_t, ret, len); /* XXX copied from tun.c. Why? */
898out:
899 return ret;
900}
901
902/*
903 * provide compatibility with generic tun/tap interface
904 */
905static long macvtap_ioctl(struct file *file, unsigned int cmd,
906 unsigned long arg)
907{
908 struct macvtap_queue *q = file->private_data;
909 struct macvlan_dev *vlan;
910 void __user *argp = (void __user *)arg;
911 struct ifreq __user *ifr = argp;
912 unsigned int __user *up = argp;
913 unsigned int u;
914 int __user *sp = argp;
915 int s;
916 int ret;
917
918 switch (cmd) {
919 case TUNSETIFF:
920 /* ignore the name, just look at flags */
921 if (get_user(u, &ifr->ifr_flags))
922 return -EFAULT;
923
924 ret = 0;
925 if ((u & ~IFF_VNET_HDR) != (IFF_NO_PI | IFF_TAP))
926 ret = -EINVAL;
927 else
928 q->flags = u;
929
930 return ret;
931
932 case TUNGETIFF:
933 rcu_read_lock_bh();
934 vlan = rcu_dereference_bh(q->vlan);
935 if (vlan)
936 dev_hold(vlan->dev);
937 rcu_read_unlock_bh();
938
939 if (!vlan)
940 return -ENOLINK;
941
942 ret = 0;
943 if (copy_to_user(&ifr->ifr_name, vlan->dev->name, IFNAMSIZ) ||
944 put_user(q->flags, &ifr->ifr_flags))
945 ret = -EFAULT;
946 dev_put(vlan->dev);
947 return ret;
948
949 case TUNGETFEATURES:
950 if (put_user(IFF_TAP | IFF_NO_PI | IFF_VNET_HDR, up))
951 return -EFAULT;
952 return 0;
953
954 case TUNSETSNDBUF:
955 if (get_user(u, up))
956 return -EFAULT;
957
958 q->sk.sk_sndbuf = u;
959 return 0;
960
961 case TUNGETVNETHDRSZ:
962 s = q->vnet_hdr_sz;
963 if (put_user(s, sp))
964 return -EFAULT;
965 return 0;
966
967 case TUNSETVNETHDRSZ:
968 if (get_user(s, sp))
969 return -EFAULT;
970 if (s < (int)sizeof(struct virtio_net_hdr))
971 return -EINVAL;
972
973 q->vnet_hdr_sz = s;
974 return 0;
975
976 case TUNSETOFFLOAD:
977 /* let the user check for future flags */
978 if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 |
979 TUN_F_TSO_ECN | TUN_F_UFO))
980 return -EINVAL;
981
982 /* TODO: only accept frames with the features that
983 got enabled for forwarded frames */
984 if (!(q->flags & IFF_VNET_HDR))
985 return -EINVAL;
986 return 0;
987
988 default:
989 return -EINVAL;
990 }
991}
992
993#ifdef CONFIG_COMPAT
994static long macvtap_compat_ioctl(struct file *file, unsigned int cmd,
995 unsigned long arg)
996{
997 return macvtap_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
998}
999#endif
1000
1001static const struct file_operations macvtap_fops = {
1002 .owner = THIS_MODULE,
1003 .open = macvtap_open,
1004 .release = macvtap_release,
1005 .aio_read = macvtap_aio_read,
1006 .aio_write = macvtap_aio_write,
1007 .poll = macvtap_poll,
1008 .llseek = no_llseek,
1009 .unlocked_ioctl = macvtap_ioctl,
1010#ifdef CONFIG_COMPAT
1011 .compat_ioctl = macvtap_compat_ioctl,
1012#endif
1013};
1014
1015static int macvtap_sendmsg(struct kiocb *iocb, struct socket *sock,
1016 struct msghdr *m, size_t total_len)
1017{
1018 struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock);
1019 return macvtap_get_user(q, m, m->msg_iov, total_len, m->msg_iovlen,
1020 m->msg_flags & MSG_DONTWAIT);
1021}
1022
1023static int macvtap_recvmsg(struct kiocb *iocb, struct socket *sock,
1024 struct msghdr *m, size_t total_len,
1025 int flags)
1026{
1027 struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock);
1028 int ret;
1029 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
1030 return -EINVAL;
1031 ret = macvtap_do_read(q, iocb, m->msg_iov, total_len,
1032 flags & MSG_DONTWAIT);
1033 if (ret > total_len) {
1034 m->msg_flags |= MSG_TRUNC;
1035 ret = flags & MSG_TRUNC ? ret : total_len;
1036 }
1037 return ret;
1038}
1039
1040/* Ops structure to mimic raw sockets with tun */
1041static const struct proto_ops macvtap_socket_ops = {
1042 .sendmsg = macvtap_sendmsg,
1043 .recvmsg = macvtap_recvmsg,
1044};
1045
1046/* Get an underlying socket object from tun file. Returns error unless file is
1047 * attached to a device. The returned object works like a packet socket, it
1048 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
1049 * holding a reference to the file for as long as the socket is in use. */
1050struct socket *macvtap_get_socket(struct file *file)
1051{
1052 struct macvtap_queue *q;
1053 if (file->f_op != &macvtap_fops)
1054 return ERR_PTR(-EINVAL);
1055 q = file->private_data;
1056 if (!q)
1057 return ERR_PTR(-EBADFD);
1058 return &q->sock;
1059}
1060EXPORT_SYMBOL_GPL(macvtap_get_socket);
1061
1062static int macvtap_device_event(struct notifier_block *unused,
1063 unsigned long event, void *ptr)
1064{
1065 struct net_device *dev = ptr;
1066 struct macvlan_dev *vlan;
1067 struct device *classdev;
1068 dev_t devt;
1069 int err;
1070
1071 if (dev->rtnl_link_ops != &macvtap_link_ops)
1072 return NOTIFY_DONE;
1073
1074 vlan = netdev_priv(dev);
1075
1076 switch (event) {
1077 case NETDEV_REGISTER:
1078 /* Create the device node here after the network device has
1079 * been registered but before register_netdevice has
1080 * finished running.
1081 */
1082 err = macvtap_get_minor(vlan);
1083 if (err)
1084 return notifier_from_errno(err);
1085
1086 devt = MKDEV(MAJOR(macvtap_major), vlan->minor);
1087 classdev = device_create(macvtap_class, &dev->dev, devt,
1088 dev, "tap%d", dev->ifindex);
1089 if (IS_ERR(classdev)) {
1090 macvtap_free_minor(vlan);
1091 return notifier_from_errno(PTR_ERR(classdev));
1092 }
1093 break;
1094 case NETDEV_UNREGISTER:
1095 devt = MKDEV(MAJOR(macvtap_major), vlan->minor);
1096 device_destroy(macvtap_class, devt);
1097 macvtap_free_minor(vlan);
1098 break;
1099 }
1100
1101 return NOTIFY_DONE;
1102}
1103
1104static struct notifier_block macvtap_notifier_block __read_mostly = {
1105 .notifier_call = macvtap_device_event,
1106};
1107
1108static int macvtap_init(void)
1109{
1110 int err;
1111
1112 err = alloc_chrdev_region(&macvtap_major, 0,
1113 MACVTAP_NUM_DEVS, "macvtap");
1114 if (err)
1115 goto out1;
1116
1117 cdev_init(&macvtap_cdev, &macvtap_fops);
1118 err = cdev_add(&macvtap_cdev, macvtap_major, MACVTAP_NUM_DEVS);
1119 if (err)
1120 goto out2;
1121
1122 macvtap_class = class_create(THIS_MODULE, "macvtap");
1123 if (IS_ERR(macvtap_class)) {
1124 err = PTR_ERR(macvtap_class);
1125 goto out3;
1126 }
1127
1128 err = register_netdevice_notifier(&macvtap_notifier_block);
1129 if (err)
1130 goto out4;
1131
1132 err = macvlan_link_register(&macvtap_link_ops);
1133 if (err)
1134 goto out5;
1135
1136 return 0;
1137
1138out5:
1139 unregister_netdevice_notifier(&macvtap_notifier_block);
1140out4:
1141 class_unregister(macvtap_class);
1142out3:
1143 cdev_del(&macvtap_cdev);
1144out2:
1145 unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);
1146out1:
1147 return err;
1148}
1149module_init(macvtap_init);
1150
1151static void macvtap_exit(void)
1152{
1153 rtnl_link_unregister(&macvtap_link_ops);
1154 unregister_netdevice_notifier(&macvtap_notifier_block);
1155 class_unregister(macvtap_class);
1156 cdev_del(&macvtap_cdev);
1157 unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);
1158}
1159module_exit(macvtap_exit);
1160
1161MODULE_ALIAS_RTNL_LINK("macvtap");
1162MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
1163MODULE_LICENSE("GPL");