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1 /*
2 * TUN - Universal TUN/TAP device driver.
3 * Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
16 */
17
18 /*
19 * Changes:
20 *
21 * Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
22 * Add TUNSETLINK ioctl to set the link encapsulation
23 *
24 * Mark Smith <markzzzsmith@yahoo.com.au>
25 * Use eth_random_addr() for tap MAC address.
26 *
27 * Harald Roelle <harald.roelle@ifi.lmu.de> 2004/04/20
28 * Fixes in packet dropping, queue length setting and queue wakeup.
29 * Increased default tx queue length.
30 * Added ethtool API.
31 * Minor cleanups
32 *
33 * Daniel Podlejski <underley@underley.eu.org>
34 * Modifications for 2.3.99-pre5 kernel.
35 */
36
37 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
38
39 #define DRV_NAME "tun"
40 #define DRV_VERSION "1.6"
41 #define DRV_DESCRIPTION "Universal TUN/TAP device driver"
42 #define DRV_COPYRIGHT "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
43
44 #include <linux/module.h>
45 #include <linux/errno.h>
46 #include <linux/kernel.h>
47 #include <linux/major.h>
48 #include <linux/slab.h>
49 #include <linux/poll.h>
50 #include <linux/fcntl.h>
51 #include <linux/init.h>
52 #include <linux/skbuff.h>
53 #include <linux/netdevice.h>
54 #include <linux/etherdevice.h>
55 #include <linux/miscdevice.h>
56 #include <linux/ethtool.h>
57 #include <linux/rtnetlink.h>
58 #include <linux/compat.h>
59 #include <linux/if.h>
60 #include <linux/if_arp.h>
61 #include <linux/if_ether.h>
62 #include <linux/if_tun.h>
63 #include <linux/if_vlan.h>
64 #include <linux/crc32.h>
65 #include <linux/nsproxy.h>
66 #include <linux/virtio_net.h>
67 #include <linux/rcupdate.h>
68 #include <net/net_namespace.h>
69 #include <net/netns/generic.h>
70 #include <net/rtnetlink.h>
71 #include <net/sock.h>
72 #include <linux/seq_file.h>
73 #include <linux/uio.h>
74 #include <linux/skb_array.h>
75
76 #include <linux/uaccess.h>
77
78 /* Uncomment to enable debugging */
79 /* #define TUN_DEBUG 1 */
80
81 #ifdef TUN_DEBUG
82 static int debug;
83
84 #define tun_debug(level, tun, fmt, args...) \
85 do { \
86 if (tun->debug) \
87 netdev_printk(level, tun->dev, fmt, ##args); \
88 } while (0)
89 #define DBG1(level, fmt, args...) \
90 do { \
91 if (debug == 2) \
92 printk(level fmt, ##args); \
93 } while (0)
94 #else
95 #define tun_debug(level, tun, fmt, args...) \
96 do { \
97 if (0) \
98 netdev_printk(level, tun->dev, fmt, ##args); \
99 } while (0)
100 #define DBG1(level, fmt, args...) \
101 do { \
102 if (0) \
103 printk(level fmt, ##args); \
104 } while (0)
105 #endif
106
107 /* TUN device flags */
108
109 /* IFF_ATTACH_QUEUE is never stored in device flags,
110 * overload it to mean fasync when stored there.
111 */
112 #define TUN_FASYNC IFF_ATTACH_QUEUE
113 /* High bits in flags field are unused. */
114 #define TUN_VNET_LE 0x80000000
115 #define TUN_VNET_BE 0x40000000
116
117 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
118 IFF_MULTI_QUEUE)
119 #define GOODCOPY_LEN 128
120
121 #define FLT_EXACT_COUNT 8
122 struct tap_filter {
123 unsigned int count; /* Number of addrs. Zero means disabled */
124 u32 mask[2]; /* Mask of the hashed addrs */
125 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
126 };
127
128 /* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
129 * to max number of VCPUs in guest. */
130 #define MAX_TAP_QUEUES 256
131 #define MAX_TAP_FLOWS 4096
132
133 #define TUN_FLOW_EXPIRE (3 * HZ)
134
135 struct tun_pcpu_stats {
136 u64 rx_packets;
137 u64 rx_bytes;
138 u64 tx_packets;
139 u64 tx_bytes;
140 struct u64_stats_sync syncp;
141 u32 rx_dropped;
142 u32 tx_dropped;
143 u32 rx_frame_errors;
144 };
145
146 /* A tun_file connects an open character device to a tuntap netdevice. It
147 * also contains all socket related structures (except sock_fprog and tap_filter)
148 * to serve as one transmit queue for tuntap device. The sock_fprog and
149 * tap_filter were kept in tun_struct since they were used for filtering for the
150 * netdevice not for a specific queue (at least I didn't see the requirement for
151 * this).
152 *
153 * RCU usage:
154 * The tun_file and tun_struct are loosely coupled, the pointer from one to the
155 * other can only be read while rcu_read_lock or rtnl_lock is held.
156 */
157 struct tun_file {
158 struct sock sk;
159 struct socket socket;
160 struct socket_wq wq;
161 struct tun_struct __rcu *tun;
162 struct fasync_struct *fasync;
163 /* only used for fasnyc */
164 unsigned int flags;
165 union {
166 u16 queue_index;
167 unsigned int ifindex;
168 };
169 struct list_head next;
170 struct tun_struct *detached;
171 struct skb_array tx_array;
172 };
173
174 struct tun_flow_entry {
175 struct hlist_node hash_link;
176 struct rcu_head rcu;
177 struct tun_struct *tun;
178
179 u32 rxhash;
180 u32 rps_rxhash;
181 int queue_index;
182 unsigned long updated;
183 };
184
185 #define TUN_NUM_FLOW_ENTRIES 1024
186
187 /* Since the socket were moved to tun_file, to preserve the behavior of persist
188 * device, socket filter, sndbuf and vnet header size were restore when the
189 * file were attached to a persist device.
190 */
191 struct tun_struct {
192 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES];
193 unsigned int numqueues;
194 unsigned int flags;
195 kuid_t owner;
196 kgid_t group;
197
198 struct net_device *dev;
199 netdev_features_t set_features;
200 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
201 NETIF_F_TSO6|NETIF_F_UFO)
202
203 int align;
204 int vnet_hdr_sz;
205 int sndbuf;
206 struct tap_filter txflt;
207 struct sock_fprog fprog;
208 /* protected by rtnl lock */
209 bool filter_attached;
210 #ifdef TUN_DEBUG
211 int debug;
212 #endif
213 spinlock_t lock;
214 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
215 struct timer_list flow_gc_timer;
216 unsigned long ageing_time;
217 unsigned int numdisabled;
218 struct list_head disabled;
219 void *security;
220 u32 flow_count;
221 struct tun_pcpu_stats __percpu *pcpu_stats;
222 };
223
224 #ifdef CONFIG_TUN_VNET_CROSS_LE
225 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
226 {
227 return tun->flags & TUN_VNET_BE ? false :
228 virtio_legacy_is_little_endian();
229 }
230
231 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
232 {
233 int be = !!(tun->flags & TUN_VNET_BE);
234
235 if (put_user(be, argp))
236 return -EFAULT;
237
238 return 0;
239 }
240
241 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
242 {
243 int be;
244
245 if (get_user(be, argp))
246 return -EFAULT;
247
248 if (be)
249 tun->flags |= TUN_VNET_BE;
250 else
251 tun->flags &= ~TUN_VNET_BE;
252
253 return 0;
254 }
255 #else
256 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
257 {
258 return virtio_legacy_is_little_endian();
259 }
260
261 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
262 {
263 return -EINVAL;
264 }
265
266 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
267 {
268 return -EINVAL;
269 }
270 #endif /* CONFIG_TUN_VNET_CROSS_LE */
271
272 static inline bool tun_is_little_endian(struct tun_struct *tun)
273 {
274 return tun->flags & TUN_VNET_LE ||
275 tun_legacy_is_little_endian(tun);
276 }
277
278 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
279 {
280 return __virtio16_to_cpu(tun_is_little_endian(tun), val);
281 }
282
283 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
284 {
285 return __cpu_to_virtio16(tun_is_little_endian(tun), val);
286 }
287
288 static inline u32 tun_hashfn(u32 rxhash)
289 {
290 return rxhash & 0x3ff;
291 }
292
293 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
294 {
295 struct tun_flow_entry *e;
296
297 hlist_for_each_entry_rcu(e, head, hash_link) {
298 if (e->rxhash == rxhash)
299 return e;
300 }
301 return NULL;
302 }
303
304 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
305 struct hlist_head *head,
306 u32 rxhash, u16 queue_index)
307 {
308 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
309
310 if (e) {
311 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
312 rxhash, queue_index);
313 e->updated = jiffies;
314 e->rxhash = rxhash;
315 e->rps_rxhash = 0;
316 e->queue_index = queue_index;
317 e->tun = tun;
318 hlist_add_head_rcu(&e->hash_link, head);
319 ++tun->flow_count;
320 }
321 return e;
322 }
323
324 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
325 {
326 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
327 e->rxhash, e->queue_index);
328 hlist_del_rcu(&e->hash_link);
329 kfree_rcu(e, rcu);
330 --tun->flow_count;
331 }
332
333 static void tun_flow_flush(struct tun_struct *tun)
334 {
335 int i;
336
337 spin_lock_bh(&tun->lock);
338 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
339 struct tun_flow_entry *e;
340 struct hlist_node *n;
341
342 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
343 tun_flow_delete(tun, e);
344 }
345 spin_unlock_bh(&tun->lock);
346 }
347
348 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
349 {
350 int i;
351
352 spin_lock_bh(&tun->lock);
353 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
354 struct tun_flow_entry *e;
355 struct hlist_node *n;
356
357 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
358 if (e->queue_index == queue_index)
359 tun_flow_delete(tun, e);
360 }
361 }
362 spin_unlock_bh(&tun->lock);
363 }
364
365 static void tun_flow_cleanup(unsigned long data)
366 {
367 struct tun_struct *tun = (struct tun_struct *)data;
368 unsigned long delay = tun->ageing_time;
369 unsigned long next_timer = jiffies + delay;
370 unsigned long count = 0;
371 int i;
372
373 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
374
375 spin_lock_bh(&tun->lock);
376 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
377 struct tun_flow_entry *e;
378 struct hlist_node *n;
379
380 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
381 unsigned long this_timer;
382 count++;
383 this_timer = e->updated + delay;
384 if (time_before_eq(this_timer, jiffies))
385 tun_flow_delete(tun, e);
386 else if (time_before(this_timer, next_timer))
387 next_timer = this_timer;
388 }
389 }
390
391 if (count)
392 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
393 spin_unlock_bh(&tun->lock);
394 }
395
396 static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
397 struct tun_file *tfile)
398 {
399 struct hlist_head *head;
400 struct tun_flow_entry *e;
401 unsigned long delay = tun->ageing_time;
402 u16 queue_index = tfile->queue_index;
403
404 if (!rxhash)
405 return;
406 else
407 head = &tun->flows[tun_hashfn(rxhash)];
408
409 rcu_read_lock();
410
411 /* We may get a very small possibility of OOO during switching, not
412 * worth to optimize.*/
413 if (tun->numqueues == 1 || tfile->detached)
414 goto unlock;
415
416 e = tun_flow_find(head, rxhash);
417 if (likely(e)) {
418 /* TODO: keep queueing to old queue until it's empty? */
419 e->queue_index = queue_index;
420 e->updated = jiffies;
421 sock_rps_record_flow_hash(e->rps_rxhash);
422 } else {
423 spin_lock_bh(&tun->lock);
424 if (!tun_flow_find(head, rxhash) &&
425 tun->flow_count < MAX_TAP_FLOWS)
426 tun_flow_create(tun, head, rxhash, queue_index);
427
428 if (!timer_pending(&tun->flow_gc_timer))
429 mod_timer(&tun->flow_gc_timer,
430 round_jiffies_up(jiffies + delay));
431 spin_unlock_bh(&tun->lock);
432 }
433
434 unlock:
435 rcu_read_unlock();
436 }
437
438 /**
439 * Save the hash received in the stack receive path and update the
440 * flow_hash table accordingly.
441 */
442 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
443 {
444 if (unlikely(e->rps_rxhash != hash))
445 e->rps_rxhash = hash;
446 }
447
448 /* We try to identify a flow through its rxhash first. The reason that
449 * we do not check rxq no. is because some cards(e.g 82599), chooses
450 * the rxq based on the txq where the last packet of the flow comes. As
451 * the userspace application move between processors, we may get a
452 * different rxq no. here. If we could not get rxhash, then we would
453 * hope the rxq no. may help here.
454 */
455 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
456 void *accel_priv, select_queue_fallback_t fallback)
457 {
458 struct tun_struct *tun = netdev_priv(dev);
459 struct tun_flow_entry *e;
460 u32 txq = 0;
461 u32 numqueues = 0;
462
463 rcu_read_lock();
464 numqueues = ACCESS_ONCE(tun->numqueues);
465
466 txq = skb_get_hash(skb);
467 if (txq) {
468 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
469 if (e) {
470 tun_flow_save_rps_rxhash(e, txq);
471 txq = e->queue_index;
472 } else
473 /* use multiply and shift instead of expensive divide */
474 txq = ((u64)txq * numqueues) >> 32;
475 } else if (likely(skb_rx_queue_recorded(skb))) {
476 txq = skb_get_rx_queue(skb);
477 while (unlikely(txq >= numqueues))
478 txq -= numqueues;
479 }
480
481 rcu_read_unlock();
482 return txq;
483 }
484
485 static inline bool tun_not_capable(struct tun_struct *tun)
486 {
487 const struct cred *cred = current_cred();
488 struct net *net = dev_net(tun->dev);
489
490 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
491 (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
492 !ns_capable(net->user_ns, CAP_NET_ADMIN);
493 }
494
495 static void tun_set_real_num_queues(struct tun_struct *tun)
496 {
497 netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
498 netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
499 }
500
501 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
502 {
503 tfile->detached = tun;
504 list_add_tail(&tfile->next, &tun->disabled);
505 ++tun->numdisabled;
506 }
507
508 static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
509 {
510 struct tun_struct *tun = tfile->detached;
511
512 tfile->detached = NULL;
513 list_del_init(&tfile->next);
514 --tun->numdisabled;
515 return tun;
516 }
517
518 static void tun_queue_purge(struct tun_file *tfile)
519 {
520 struct sk_buff *skb;
521
522 while ((skb = skb_array_consume(&tfile->tx_array)) != NULL)
523 kfree_skb(skb);
524
525 skb_queue_purge(&tfile->sk.sk_error_queue);
526 }
527
528 static void __tun_detach(struct tun_file *tfile, bool clean)
529 {
530 struct tun_file *ntfile;
531 struct tun_struct *tun;
532
533 tun = rtnl_dereference(tfile->tun);
534
535 if (tun && !tfile->detached) {
536 u16 index = tfile->queue_index;
537 BUG_ON(index >= tun->numqueues);
538
539 rcu_assign_pointer(tun->tfiles[index],
540 tun->tfiles[tun->numqueues - 1]);
541 ntfile = rtnl_dereference(tun->tfiles[index]);
542 ntfile->queue_index = index;
543
544 --tun->numqueues;
545 if (clean) {
546 RCU_INIT_POINTER(tfile->tun, NULL);
547 sock_put(&tfile->sk);
548 } else
549 tun_disable_queue(tun, tfile);
550
551 synchronize_net();
552 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
553 /* Drop read queue */
554 tun_queue_purge(tfile);
555 tun_set_real_num_queues(tun);
556 } else if (tfile->detached && clean) {
557 tun = tun_enable_queue(tfile);
558 sock_put(&tfile->sk);
559 }
560
561 if (clean) {
562 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
563 netif_carrier_off(tun->dev);
564
565 if (!(tun->flags & IFF_PERSIST) &&
566 tun->dev->reg_state == NETREG_REGISTERED)
567 unregister_netdevice(tun->dev);
568 }
569 if (tun)
570 skb_array_cleanup(&tfile->tx_array);
571 sock_put(&tfile->sk);
572 }
573 }
574
575 static void tun_detach(struct tun_file *tfile, bool clean)
576 {
577 rtnl_lock();
578 __tun_detach(tfile, clean);
579 rtnl_unlock();
580 }
581
582 static void tun_detach_all(struct net_device *dev)
583 {
584 struct tun_struct *tun = netdev_priv(dev);
585 struct tun_file *tfile, *tmp;
586 int i, n = tun->numqueues;
587
588 for (i = 0; i < n; i++) {
589 tfile = rtnl_dereference(tun->tfiles[i]);
590 BUG_ON(!tfile);
591 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
592 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
593 RCU_INIT_POINTER(tfile->tun, NULL);
594 --tun->numqueues;
595 }
596 list_for_each_entry(tfile, &tun->disabled, next) {
597 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
598 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
599 RCU_INIT_POINTER(tfile->tun, NULL);
600 }
601 BUG_ON(tun->numqueues != 0);
602
603 synchronize_net();
604 for (i = 0; i < n; i++) {
605 tfile = rtnl_dereference(tun->tfiles[i]);
606 /* Drop read queue */
607 tun_queue_purge(tfile);
608 sock_put(&tfile->sk);
609 }
610 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
611 tun_enable_queue(tfile);
612 tun_queue_purge(tfile);
613 sock_put(&tfile->sk);
614 }
615 BUG_ON(tun->numdisabled != 0);
616
617 if (tun->flags & IFF_PERSIST)
618 module_put(THIS_MODULE);
619 }
620
621 static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter)
622 {
623 struct tun_file *tfile = file->private_data;
624 struct net_device *dev = tun->dev;
625 int err;
626
627 err = security_tun_dev_attach(tfile->socket.sk, tun->security);
628 if (err < 0)
629 goto out;
630
631 err = -EINVAL;
632 if (rtnl_dereference(tfile->tun) && !tfile->detached)
633 goto out;
634
635 err = -EBUSY;
636 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
637 goto out;
638
639 err = -E2BIG;
640 if (!tfile->detached &&
641 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
642 goto out;
643
644 err = 0;
645
646 /* Re-attach the filter to persist device */
647 if (!skip_filter && (tun->filter_attached == true)) {
648 lock_sock(tfile->socket.sk);
649 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
650 release_sock(tfile->socket.sk);
651 if (!err)
652 goto out;
653 }
654
655 if (!tfile->detached &&
656 skb_array_init(&tfile->tx_array, dev->tx_queue_len, GFP_KERNEL)) {
657 err = -ENOMEM;
658 goto out;
659 }
660
661 tfile->queue_index = tun->numqueues;
662 tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
663 rcu_assign_pointer(tfile->tun, tun);
664 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
665 tun->numqueues++;
666
667 if (tfile->detached)
668 tun_enable_queue(tfile);
669 else
670 sock_hold(&tfile->sk);
671
672 tun_set_real_num_queues(tun);
673
674 /* device is allowed to go away first, so no need to hold extra
675 * refcnt.
676 */
677
678 out:
679 return err;
680 }
681
682 static struct tun_struct *__tun_get(struct tun_file *tfile)
683 {
684 struct tun_struct *tun;
685
686 rcu_read_lock();
687 tun = rcu_dereference(tfile->tun);
688 if (tun)
689 dev_hold(tun->dev);
690 rcu_read_unlock();
691
692 return tun;
693 }
694
695 static struct tun_struct *tun_get(struct file *file)
696 {
697 return __tun_get(file->private_data);
698 }
699
700 static void tun_put(struct tun_struct *tun)
701 {
702 dev_put(tun->dev);
703 }
704
705 /* TAP filtering */
706 static void addr_hash_set(u32 *mask, const u8 *addr)
707 {
708 int n = ether_crc(ETH_ALEN, addr) >> 26;
709 mask[n >> 5] |= (1 << (n & 31));
710 }
711
712 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
713 {
714 int n = ether_crc(ETH_ALEN, addr) >> 26;
715 return mask[n >> 5] & (1 << (n & 31));
716 }
717
718 static int update_filter(struct tap_filter *filter, void __user *arg)
719 {
720 struct { u8 u[ETH_ALEN]; } *addr;
721 struct tun_filter uf;
722 int err, alen, n, nexact;
723
724 if (copy_from_user(&uf, arg, sizeof(uf)))
725 return -EFAULT;
726
727 if (!uf.count) {
728 /* Disabled */
729 filter->count = 0;
730 return 0;
731 }
732
733 alen = ETH_ALEN * uf.count;
734 addr = memdup_user(arg + sizeof(uf), alen);
735 if (IS_ERR(addr))
736 return PTR_ERR(addr);
737
738 /* The filter is updated without holding any locks. Which is
739 * perfectly safe. We disable it first and in the worst
740 * case we'll accept a few undesired packets. */
741 filter->count = 0;
742 wmb();
743
744 /* Use first set of addresses as an exact filter */
745 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
746 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
747
748 nexact = n;
749
750 /* Remaining multicast addresses are hashed,
751 * unicast will leave the filter disabled. */
752 memset(filter->mask, 0, sizeof(filter->mask));
753 for (; n < uf.count; n++) {
754 if (!is_multicast_ether_addr(addr[n].u)) {
755 err = 0; /* no filter */
756 goto free_addr;
757 }
758 addr_hash_set(filter->mask, addr[n].u);
759 }
760
761 /* For ALLMULTI just set the mask to all ones.
762 * This overrides the mask populated above. */
763 if ((uf.flags & TUN_FLT_ALLMULTI))
764 memset(filter->mask, ~0, sizeof(filter->mask));
765
766 /* Now enable the filter */
767 wmb();
768 filter->count = nexact;
769
770 /* Return the number of exact filters */
771 err = nexact;
772 free_addr:
773 kfree(addr);
774 return err;
775 }
776
777 /* Returns: 0 - drop, !=0 - accept */
778 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
779 {
780 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
781 * at this point. */
782 struct ethhdr *eh = (struct ethhdr *) skb->data;
783 int i;
784
785 /* Exact match */
786 for (i = 0; i < filter->count; i++)
787 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
788 return 1;
789
790 /* Inexact match (multicast only) */
791 if (is_multicast_ether_addr(eh->h_dest))
792 return addr_hash_test(filter->mask, eh->h_dest);
793
794 return 0;
795 }
796
797 /*
798 * Checks whether the packet is accepted or not.
799 * Returns: 0 - drop, !=0 - accept
800 */
801 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
802 {
803 if (!filter->count)
804 return 1;
805
806 return run_filter(filter, skb);
807 }
808
809 /* Network device part of the driver */
810
811 static const struct ethtool_ops tun_ethtool_ops;
812
813 /* Net device detach from fd. */
814 static void tun_net_uninit(struct net_device *dev)
815 {
816 tun_detach_all(dev);
817 }
818
819 /* Net device open. */
820 static int tun_net_open(struct net_device *dev)
821 {
822 struct tun_struct *tun = netdev_priv(dev);
823 int i;
824
825 netif_tx_start_all_queues(dev);
826
827 for (i = 0; i < tun->numqueues; i++) {
828 struct tun_file *tfile;
829
830 tfile = rtnl_dereference(tun->tfiles[i]);
831 tfile->socket.sk->sk_write_space(tfile->socket.sk);
832 }
833
834 return 0;
835 }
836
837 /* Net device close. */
838 static int tun_net_close(struct net_device *dev)
839 {
840 netif_tx_stop_all_queues(dev);
841 return 0;
842 }
843
844 /* Net device start xmit */
845 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
846 {
847 struct tun_struct *tun = netdev_priv(dev);
848 int txq = skb->queue_mapping;
849 struct tun_file *tfile;
850 u32 numqueues = 0;
851
852 rcu_read_lock();
853 tfile = rcu_dereference(tun->tfiles[txq]);
854 numqueues = ACCESS_ONCE(tun->numqueues);
855
856 /* Drop packet if interface is not attached */
857 if (txq >= numqueues)
858 goto drop;
859
860 #ifdef CONFIG_RPS
861 if (numqueues == 1 && static_key_false(&rps_needed)) {
862 /* Select queue was not called for the skbuff, so we extract the
863 * RPS hash and save it into the flow_table here.
864 */
865 __u32 rxhash;
866
867 rxhash = skb_get_hash(skb);
868 if (rxhash) {
869 struct tun_flow_entry *e;
870 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)],
871 rxhash);
872 if (e)
873 tun_flow_save_rps_rxhash(e, rxhash);
874 }
875 }
876 #endif
877
878 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
879
880 BUG_ON(!tfile);
881
882 /* Drop if the filter does not like it.
883 * This is a noop if the filter is disabled.
884 * Filter can be enabled only for the TAP devices. */
885 if (!check_filter(&tun->txflt, skb))
886 goto drop;
887
888 if (tfile->socket.sk->sk_filter &&
889 sk_filter(tfile->socket.sk, skb))
890 goto drop;
891
892 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
893 goto drop;
894
895 skb_tx_timestamp(skb);
896
897 /* Orphan the skb - required as we might hang on to it
898 * for indefinite time.
899 */
900 skb_orphan(skb);
901
902 nf_reset(skb);
903
904 if (skb_array_produce(&tfile->tx_array, skb))
905 goto drop;
906
907 /* Notify and wake up reader process */
908 if (tfile->flags & TUN_FASYNC)
909 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
910 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
911
912 rcu_read_unlock();
913 return NETDEV_TX_OK;
914
915 drop:
916 this_cpu_inc(tun->pcpu_stats->tx_dropped);
917 skb_tx_error(skb);
918 kfree_skb(skb);
919 rcu_read_unlock();
920 return NET_XMIT_DROP;
921 }
922
923 static void tun_net_mclist(struct net_device *dev)
924 {
925 /*
926 * This callback is supposed to deal with mc filter in
927 * _rx_ path and has nothing to do with the _tx_ path.
928 * In rx path we always accept everything userspace gives us.
929 */
930 }
931
932 static netdev_features_t tun_net_fix_features(struct net_device *dev,
933 netdev_features_t features)
934 {
935 struct tun_struct *tun = netdev_priv(dev);
936
937 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
938 }
939 #ifdef CONFIG_NET_POLL_CONTROLLER
940 static void tun_poll_controller(struct net_device *dev)
941 {
942 /*
943 * Tun only receives frames when:
944 * 1) the char device endpoint gets data from user space
945 * 2) the tun socket gets a sendmsg call from user space
946 * Since both of those are synchronous operations, we are guaranteed
947 * never to have pending data when we poll for it
948 * so there is nothing to do here but return.
949 * We need this though so netpoll recognizes us as an interface that
950 * supports polling, which enables bridge devices in virt setups to
951 * still use netconsole
952 */
953 return;
954 }
955 #endif
956
957 static void tun_set_headroom(struct net_device *dev, int new_hr)
958 {
959 struct tun_struct *tun = netdev_priv(dev);
960
961 if (new_hr < NET_SKB_PAD)
962 new_hr = NET_SKB_PAD;
963
964 tun->align = new_hr;
965 }
966
967 static struct rtnl_link_stats64 *
968 tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
969 {
970 u32 rx_dropped = 0, tx_dropped = 0, rx_frame_errors = 0;
971 struct tun_struct *tun = netdev_priv(dev);
972 struct tun_pcpu_stats *p;
973 int i;
974
975 for_each_possible_cpu(i) {
976 u64 rxpackets, rxbytes, txpackets, txbytes;
977 unsigned int start;
978
979 p = per_cpu_ptr(tun->pcpu_stats, i);
980 do {
981 start = u64_stats_fetch_begin(&p->syncp);
982 rxpackets = p->rx_packets;
983 rxbytes = p->rx_bytes;
984 txpackets = p->tx_packets;
985 txbytes = p->tx_bytes;
986 } while (u64_stats_fetch_retry(&p->syncp, start));
987
988 stats->rx_packets += rxpackets;
989 stats->rx_bytes += rxbytes;
990 stats->tx_packets += txpackets;
991 stats->tx_bytes += txbytes;
992
993 /* u32 counters */
994 rx_dropped += p->rx_dropped;
995 rx_frame_errors += p->rx_frame_errors;
996 tx_dropped += p->tx_dropped;
997 }
998 stats->rx_dropped = rx_dropped;
999 stats->rx_frame_errors = rx_frame_errors;
1000 stats->tx_dropped = tx_dropped;
1001 return stats;
1002 }
1003
1004 static const struct net_device_ops tun_netdev_ops = {
1005 .ndo_uninit = tun_net_uninit,
1006 .ndo_open = tun_net_open,
1007 .ndo_stop = tun_net_close,
1008 .ndo_start_xmit = tun_net_xmit,
1009 .ndo_fix_features = tun_net_fix_features,
1010 .ndo_select_queue = tun_select_queue,
1011 #ifdef CONFIG_NET_POLL_CONTROLLER
1012 .ndo_poll_controller = tun_poll_controller,
1013 #endif
1014 .ndo_set_rx_headroom = tun_set_headroom,
1015 .ndo_get_stats64 = tun_net_get_stats64,
1016 };
1017
1018 static const struct net_device_ops tap_netdev_ops = {
1019 .ndo_uninit = tun_net_uninit,
1020 .ndo_open = tun_net_open,
1021 .ndo_stop = tun_net_close,
1022 .ndo_start_xmit = tun_net_xmit,
1023 .ndo_fix_features = tun_net_fix_features,
1024 .ndo_set_rx_mode = tun_net_mclist,
1025 .ndo_set_mac_address = eth_mac_addr,
1026 .ndo_validate_addr = eth_validate_addr,
1027 .ndo_select_queue = tun_select_queue,
1028 #ifdef CONFIG_NET_POLL_CONTROLLER
1029 .ndo_poll_controller = tun_poll_controller,
1030 #endif
1031 .ndo_features_check = passthru_features_check,
1032 .ndo_set_rx_headroom = tun_set_headroom,
1033 .ndo_get_stats64 = tun_net_get_stats64,
1034 };
1035
1036 static void tun_flow_init(struct tun_struct *tun)
1037 {
1038 int i;
1039
1040 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1041 INIT_HLIST_HEAD(&tun->flows[i]);
1042
1043 tun->ageing_time = TUN_FLOW_EXPIRE;
1044 setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun);
1045 mod_timer(&tun->flow_gc_timer,
1046 round_jiffies_up(jiffies + tun->ageing_time));
1047 }
1048
1049 static void tun_flow_uninit(struct tun_struct *tun)
1050 {
1051 del_timer_sync(&tun->flow_gc_timer);
1052 tun_flow_flush(tun);
1053 }
1054
1055 #define MIN_MTU 68
1056 #define MAX_MTU 65535
1057
1058 /* Initialize net device. */
1059 static void tun_net_init(struct net_device *dev)
1060 {
1061 struct tun_struct *tun = netdev_priv(dev);
1062
1063 switch (tun->flags & TUN_TYPE_MASK) {
1064 case IFF_TUN:
1065 dev->netdev_ops = &tun_netdev_ops;
1066
1067 /* Point-to-Point TUN Device */
1068 dev->hard_header_len = 0;
1069 dev->addr_len = 0;
1070 dev->mtu = 1500;
1071
1072 /* Zero header length */
1073 dev->type = ARPHRD_NONE;
1074 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1075 break;
1076
1077 case IFF_TAP:
1078 dev->netdev_ops = &tap_netdev_ops;
1079 /* Ethernet TAP Device */
1080 ether_setup(dev);
1081 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1082 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1083
1084 eth_hw_addr_random(dev);
1085
1086 break;
1087 }
1088
1089 dev->min_mtu = MIN_MTU;
1090 dev->max_mtu = MAX_MTU - dev->hard_header_len;
1091 }
1092
1093 /* Character device part */
1094
1095 /* Poll */
1096 static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
1097 {
1098 struct tun_file *tfile = file->private_data;
1099 struct tun_struct *tun = __tun_get(tfile);
1100 struct sock *sk;
1101 unsigned int mask = 0;
1102
1103 if (!tun)
1104 return POLLERR;
1105
1106 sk = tfile->socket.sk;
1107
1108 tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
1109
1110 poll_wait(file, sk_sleep(sk), wait);
1111
1112 if (!skb_array_empty(&tfile->tx_array))
1113 mask |= POLLIN | POLLRDNORM;
1114
1115 if (tun->dev->flags & IFF_UP &&
1116 (sock_writeable(sk) ||
1117 (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1118 sock_writeable(sk))))
1119 mask |= POLLOUT | POLLWRNORM;
1120
1121 if (tun->dev->reg_state != NETREG_REGISTERED)
1122 mask = POLLERR;
1123
1124 tun_put(tun);
1125 return mask;
1126 }
1127
1128 /* prepad is the amount to reserve at front. len is length after that.
1129 * linear is a hint as to how much to copy (usually headers). */
1130 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1131 size_t prepad, size_t len,
1132 size_t linear, int noblock)
1133 {
1134 struct sock *sk = tfile->socket.sk;
1135 struct sk_buff *skb;
1136 int err;
1137
1138 /* Under a page? Don't bother with paged skb. */
1139 if (prepad + len < PAGE_SIZE || !linear)
1140 linear = len;
1141
1142 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1143 &err, 0);
1144 if (!skb)
1145 return ERR_PTR(err);
1146
1147 skb_reserve(skb, prepad);
1148 skb_put(skb, linear);
1149 skb->data_len = len - linear;
1150 skb->len += len - linear;
1151
1152 return skb;
1153 }
1154
1155 /* Get packet from user space buffer */
1156 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1157 void *msg_control, struct iov_iter *from,
1158 int noblock)
1159 {
1160 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1161 struct sk_buff *skb;
1162 size_t total_len = iov_iter_count(from);
1163 size_t len = total_len, align = tun->align, linear;
1164 struct virtio_net_hdr gso = { 0 };
1165 struct tun_pcpu_stats *stats;
1166 int good_linear;
1167 int copylen;
1168 bool zerocopy = false;
1169 int err;
1170 u32 rxhash;
1171
1172 if (!(tun->dev->flags & IFF_UP))
1173 return -EIO;
1174
1175 if (!(tun->flags & IFF_NO_PI)) {
1176 if (len < sizeof(pi))
1177 return -EINVAL;
1178 len -= sizeof(pi);
1179
1180 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1181 return -EFAULT;
1182 }
1183
1184 if (tun->flags & IFF_VNET_HDR) {
1185 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1186
1187 if (len < vnet_hdr_sz)
1188 return -EINVAL;
1189 len -= vnet_hdr_sz;
1190
1191 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1192 return -EFAULT;
1193
1194 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1195 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1196 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1197
1198 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1199 return -EINVAL;
1200 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1201 }
1202
1203 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1204 align += NET_IP_ALIGN;
1205 if (unlikely(len < ETH_HLEN ||
1206 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1207 return -EINVAL;
1208 }
1209
1210 good_linear = SKB_MAX_HEAD(align);
1211
1212 if (msg_control) {
1213 struct iov_iter i = *from;
1214
1215 /* There are 256 bytes to be copied in skb, so there is
1216 * enough room for skb expand head in case it is used.
1217 * The rest of the buffer is mapped from userspace.
1218 */
1219 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1220 if (copylen > good_linear)
1221 copylen = good_linear;
1222 linear = copylen;
1223 iov_iter_advance(&i, copylen);
1224 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1225 zerocopy = true;
1226 }
1227
1228 if (!zerocopy) {
1229 copylen = len;
1230 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1231 linear = good_linear;
1232 else
1233 linear = tun16_to_cpu(tun, gso.hdr_len);
1234 }
1235
1236 skb = tun_alloc_skb(tfile, align, copylen, linear, noblock);
1237 if (IS_ERR(skb)) {
1238 if (PTR_ERR(skb) != -EAGAIN)
1239 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1240 return PTR_ERR(skb);
1241 }
1242
1243 if (zerocopy)
1244 err = zerocopy_sg_from_iter(skb, from);
1245 else
1246 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1247
1248 if (err) {
1249 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1250 kfree_skb(skb);
1251 return -EFAULT;
1252 }
1253
1254 if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1255 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
1256 kfree_skb(skb);
1257 return -EINVAL;
1258 }
1259
1260 switch (tun->flags & TUN_TYPE_MASK) {
1261 case IFF_TUN:
1262 if (tun->flags & IFF_NO_PI) {
1263 switch (skb->data[0] & 0xf0) {
1264 case 0x40:
1265 pi.proto = htons(ETH_P_IP);
1266 break;
1267 case 0x60:
1268 pi.proto = htons(ETH_P_IPV6);
1269 break;
1270 default:
1271 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1272 kfree_skb(skb);
1273 return -EINVAL;
1274 }
1275 }
1276
1277 skb_reset_mac_header(skb);
1278 skb->protocol = pi.proto;
1279 skb->dev = tun->dev;
1280 break;
1281 case IFF_TAP:
1282 skb->protocol = eth_type_trans(skb, tun->dev);
1283 break;
1284 }
1285
1286 /* copy skb_ubuf_info for callback when skb has no error */
1287 if (zerocopy) {
1288 skb_shinfo(skb)->destructor_arg = msg_control;
1289 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1290 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1291 } else if (msg_control) {
1292 struct ubuf_info *uarg = msg_control;
1293 uarg->callback(uarg, false);
1294 }
1295
1296 skb_reset_network_header(skb);
1297 skb_probe_transport_header(skb, 0);
1298
1299 rxhash = skb_get_hash(skb);
1300 #ifndef CONFIG_4KSTACKS
1301 local_bh_disable();
1302 netif_receive_skb(skb);
1303 local_bh_enable();
1304 #else
1305 netif_rx_ni(skb);
1306 #endif
1307
1308 stats = get_cpu_ptr(tun->pcpu_stats);
1309 u64_stats_update_begin(&stats->syncp);
1310 stats->rx_packets++;
1311 stats->rx_bytes += len;
1312 u64_stats_update_end(&stats->syncp);
1313 put_cpu_ptr(stats);
1314
1315 tun_flow_update(tun, rxhash, tfile);
1316 return total_len;
1317 }
1318
1319 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
1320 {
1321 struct file *file = iocb->ki_filp;
1322 struct tun_struct *tun = tun_get(file);
1323 struct tun_file *tfile = file->private_data;
1324 ssize_t result;
1325
1326 if (!tun)
1327 return -EBADFD;
1328
1329 result = tun_get_user(tun, tfile, NULL, from, file->f_flags & O_NONBLOCK);
1330
1331 tun_put(tun);
1332 return result;
1333 }
1334
1335 /* Put packet to the user space buffer */
1336 static ssize_t tun_put_user(struct tun_struct *tun,
1337 struct tun_file *tfile,
1338 struct sk_buff *skb,
1339 struct iov_iter *iter)
1340 {
1341 struct tun_pi pi = { 0, skb->protocol };
1342 struct tun_pcpu_stats *stats;
1343 ssize_t total;
1344 int vlan_offset = 0;
1345 int vlan_hlen = 0;
1346 int vnet_hdr_sz = 0;
1347
1348 if (skb_vlan_tag_present(skb))
1349 vlan_hlen = VLAN_HLEN;
1350
1351 if (tun->flags & IFF_VNET_HDR)
1352 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1353
1354 total = skb->len + vlan_hlen + vnet_hdr_sz;
1355
1356 if (!(tun->flags & IFF_NO_PI)) {
1357 if (iov_iter_count(iter) < sizeof(pi))
1358 return -EINVAL;
1359
1360 total += sizeof(pi);
1361 if (iov_iter_count(iter) < total) {
1362 /* Packet will be striped */
1363 pi.flags |= TUN_PKT_STRIP;
1364 }
1365
1366 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
1367 return -EFAULT;
1368 }
1369
1370 if (vnet_hdr_sz) {
1371 struct virtio_net_hdr gso;
1372
1373 if (iov_iter_count(iter) < vnet_hdr_sz)
1374 return -EINVAL;
1375
1376 if (virtio_net_hdr_from_skb(skb, &gso,
1377 tun_is_little_endian(tun), true)) {
1378 struct skb_shared_info *sinfo = skb_shinfo(skb);
1379 pr_err("unexpected GSO type: "
1380 "0x%x, gso_size %d, hdr_len %d\n",
1381 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
1382 tun16_to_cpu(tun, gso.hdr_len));
1383 print_hex_dump(KERN_ERR, "tun: ",
1384 DUMP_PREFIX_NONE,
1385 16, 1, skb->head,
1386 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
1387 WARN_ON_ONCE(1);
1388 return -EINVAL;
1389 }
1390
1391 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
1392 return -EFAULT;
1393
1394 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
1395 }
1396
1397 if (vlan_hlen) {
1398 int ret;
1399 struct {
1400 __be16 h_vlan_proto;
1401 __be16 h_vlan_TCI;
1402 } veth;
1403
1404 veth.h_vlan_proto = skb->vlan_proto;
1405 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
1406
1407 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
1408
1409 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
1410 if (ret || !iov_iter_count(iter))
1411 goto done;
1412
1413 ret = copy_to_iter(&veth, sizeof(veth), iter);
1414 if (ret != sizeof(veth) || !iov_iter_count(iter))
1415 goto done;
1416 }
1417
1418 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
1419
1420 done:
1421 /* caller is in process context, */
1422 stats = get_cpu_ptr(tun->pcpu_stats);
1423 u64_stats_update_begin(&stats->syncp);
1424 stats->tx_packets++;
1425 stats->tx_bytes += skb->len + vlan_hlen;
1426 u64_stats_update_end(&stats->syncp);
1427 put_cpu_ptr(tun->pcpu_stats);
1428
1429 return total;
1430 }
1431
1432 static struct sk_buff *tun_ring_recv(struct tun_file *tfile, int noblock,
1433 int *err)
1434 {
1435 DECLARE_WAITQUEUE(wait, current);
1436 struct sk_buff *skb = NULL;
1437 int error = 0;
1438
1439 skb = skb_array_consume(&tfile->tx_array);
1440 if (skb)
1441 goto out;
1442 if (noblock) {
1443 error = -EAGAIN;
1444 goto out;
1445 }
1446
1447 add_wait_queue(&tfile->wq.wait, &wait);
1448 current->state = TASK_INTERRUPTIBLE;
1449
1450 while (1) {
1451 skb = skb_array_consume(&tfile->tx_array);
1452 if (skb)
1453 break;
1454 if (signal_pending(current)) {
1455 error = -ERESTARTSYS;
1456 break;
1457 }
1458 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
1459 error = -EFAULT;
1460 break;
1461 }
1462
1463 schedule();
1464 }
1465
1466 current->state = TASK_RUNNING;
1467 remove_wait_queue(&tfile->wq.wait, &wait);
1468
1469 out:
1470 *err = error;
1471 return skb;
1472 }
1473
1474 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
1475 struct iov_iter *to,
1476 int noblock)
1477 {
1478 struct sk_buff *skb;
1479 ssize_t ret;
1480 int err;
1481
1482 tun_debug(KERN_INFO, tun, "tun_do_read\n");
1483
1484 if (!iov_iter_count(to))
1485 return 0;
1486
1487 /* Read frames from ring */
1488 skb = tun_ring_recv(tfile, noblock, &err);
1489 if (!skb)
1490 return err;
1491
1492 ret = tun_put_user(tun, tfile, skb, to);
1493 if (unlikely(ret < 0))
1494 kfree_skb(skb);
1495 else
1496 consume_skb(skb);
1497
1498 return ret;
1499 }
1500
1501 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
1502 {
1503 struct file *file = iocb->ki_filp;
1504 struct tun_file *tfile = file->private_data;
1505 struct tun_struct *tun = __tun_get(tfile);
1506 ssize_t len = iov_iter_count(to), ret;
1507
1508 if (!tun)
1509 return -EBADFD;
1510 ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK);
1511 ret = min_t(ssize_t, ret, len);
1512 if (ret > 0)
1513 iocb->ki_pos = ret;
1514 tun_put(tun);
1515 return ret;
1516 }
1517
1518 static void tun_free_netdev(struct net_device *dev)
1519 {
1520 struct tun_struct *tun = netdev_priv(dev);
1521
1522 BUG_ON(!(list_empty(&tun->disabled)));
1523 free_percpu(tun->pcpu_stats);
1524 tun_flow_uninit(tun);
1525 security_tun_dev_free_security(tun->security);
1526 free_netdev(dev);
1527 }
1528
1529 static void tun_setup(struct net_device *dev)
1530 {
1531 struct tun_struct *tun = netdev_priv(dev);
1532
1533 tun->owner = INVALID_UID;
1534 tun->group = INVALID_GID;
1535
1536 dev->ethtool_ops = &tun_ethtool_ops;
1537 dev->destructor = tun_free_netdev;
1538 /* We prefer our own queue length */
1539 dev->tx_queue_len = TUN_READQ_SIZE;
1540 }
1541
1542 /* Trivial set of netlink ops to allow deleting tun or tap
1543 * device with netlink.
1544 */
1545 static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
1546 {
1547 return -EINVAL;
1548 }
1549
1550 static struct rtnl_link_ops tun_link_ops __read_mostly = {
1551 .kind = DRV_NAME,
1552 .priv_size = sizeof(struct tun_struct),
1553 .setup = tun_setup,
1554 .validate = tun_validate,
1555 };
1556
1557 static void tun_sock_write_space(struct sock *sk)
1558 {
1559 struct tun_file *tfile;
1560 wait_queue_head_t *wqueue;
1561
1562 if (!sock_writeable(sk))
1563 return;
1564
1565 if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
1566 return;
1567
1568 wqueue = sk_sleep(sk);
1569 if (wqueue && waitqueue_active(wqueue))
1570 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1571 POLLWRNORM | POLLWRBAND);
1572
1573 tfile = container_of(sk, struct tun_file, sk);
1574 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
1575 }
1576
1577 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
1578 {
1579 int ret;
1580 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1581 struct tun_struct *tun = __tun_get(tfile);
1582
1583 if (!tun)
1584 return -EBADFD;
1585
1586 ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter,
1587 m->msg_flags & MSG_DONTWAIT);
1588 tun_put(tun);
1589 return ret;
1590 }
1591
1592 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
1593 int flags)
1594 {
1595 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1596 struct tun_struct *tun = __tun_get(tfile);
1597 int ret;
1598
1599 if (!tun)
1600 return -EBADFD;
1601
1602 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
1603 ret = -EINVAL;
1604 goto out;
1605 }
1606 if (flags & MSG_ERRQUEUE) {
1607 ret = sock_recv_errqueue(sock->sk, m, total_len,
1608 SOL_PACKET, TUN_TX_TIMESTAMP);
1609 goto out;
1610 }
1611 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT);
1612 if (ret > (ssize_t)total_len) {
1613 m->msg_flags |= MSG_TRUNC;
1614 ret = flags & MSG_TRUNC ? ret : total_len;
1615 }
1616 out:
1617 tun_put(tun);
1618 return ret;
1619 }
1620
1621 static int tun_peek_len(struct socket *sock)
1622 {
1623 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1624 struct tun_struct *tun;
1625 int ret = 0;
1626
1627 tun = __tun_get(tfile);
1628 if (!tun)
1629 return 0;
1630
1631 ret = skb_array_peek_len(&tfile->tx_array);
1632 tun_put(tun);
1633
1634 return ret;
1635 }
1636
1637 /* Ops structure to mimic raw sockets with tun */
1638 static const struct proto_ops tun_socket_ops = {
1639 .peek_len = tun_peek_len,
1640 .sendmsg = tun_sendmsg,
1641 .recvmsg = tun_recvmsg,
1642 };
1643
1644 static struct proto tun_proto = {
1645 .name = "tun",
1646 .owner = THIS_MODULE,
1647 .obj_size = sizeof(struct tun_file),
1648 };
1649
1650 static int tun_flags(struct tun_struct *tun)
1651 {
1652 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
1653 }
1654
1655 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1656 char *buf)
1657 {
1658 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1659 return sprintf(buf, "0x%x\n", tun_flags(tun));
1660 }
1661
1662 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1663 char *buf)
1664 {
1665 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1666 return uid_valid(tun->owner)?
1667 sprintf(buf, "%u\n",
1668 from_kuid_munged(current_user_ns(), tun->owner)):
1669 sprintf(buf, "-1\n");
1670 }
1671
1672 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1673 char *buf)
1674 {
1675 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1676 return gid_valid(tun->group) ?
1677 sprintf(buf, "%u\n",
1678 from_kgid_munged(current_user_ns(), tun->group)):
1679 sprintf(buf, "-1\n");
1680 }
1681
1682 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1683 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1684 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1685
1686 static struct attribute *tun_dev_attrs[] = {
1687 &dev_attr_tun_flags.attr,
1688 &dev_attr_owner.attr,
1689 &dev_attr_group.attr,
1690 NULL
1691 };
1692
1693 static const struct attribute_group tun_attr_group = {
1694 .attrs = tun_dev_attrs
1695 };
1696
1697 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1698 {
1699 struct tun_struct *tun;
1700 struct tun_file *tfile = file->private_data;
1701 struct net_device *dev;
1702 int err;
1703
1704 if (tfile->detached)
1705 return -EINVAL;
1706
1707 dev = __dev_get_by_name(net, ifr->ifr_name);
1708 if (dev) {
1709 if (ifr->ifr_flags & IFF_TUN_EXCL)
1710 return -EBUSY;
1711 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1712 tun = netdev_priv(dev);
1713 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1714 tun = netdev_priv(dev);
1715 else
1716 return -EINVAL;
1717
1718 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
1719 !!(tun->flags & IFF_MULTI_QUEUE))
1720 return -EINVAL;
1721
1722 if (tun_not_capable(tun))
1723 return -EPERM;
1724 err = security_tun_dev_open(tun->security);
1725 if (err < 0)
1726 return err;
1727
1728 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER);
1729 if (err < 0)
1730 return err;
1731
1732 if (tun->flags & IFF_MULTI_QUEUE &&
1733 (tun->numqueues + tun->numdisabled > 1)) {
1734 /* One or more queue has already been attached, no need
1735 * to initialize the device again.
1736 */
1737 return 0;
1738 }
1739 }
1740 else {
1741 char *name;
1742 unsigned long flags = 0;
1743 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
1744 MAX_TAP_QUEUES : 1;
1745
1746 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1747 return -EPERM;
1748 err = security_tun_dev_create();
1749 if (err < 0)
1750 return err;
1751
1752 /* Set dev type */
1753 if (ifr->ifr_flags & IFF_TUN) {
1754 /* TUN device */
1755 flags |= IFF_TUN;
1756 name = "tun%d";
1757 } else if (ifr->ifr_flags & IFF_TAP) {
1758 /* TAP device */
1759 flags |= IFF_TAP;
1760 name = "tap%d";
1761 } else
1762 return -EINVAL;
1763
1764 if (*ifr->ifr_name)
1765 name = ifr->ifr_name;
1766
1767 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
1768 NET_NAME_UNKNOWN, tun_setup, queues,
1769 queues);
1770
1771 if (!dev)
1772 return -ENOMEM;
1773
1774 dev_net_set(dev, net);
1775 dev->rtnl_link_ops = &tun_link_ops;
1776 dev->ifindex = tfile->ifindex;
1777 dev->sysfs_groups[0] = &tun_attr_group;
1778
1779 tun = netdev_priv(dev);
1780 tun->dev = dev;
1781 tun->flags = flags;
1782 tun->txflt.count = 0;
1783 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1784
1785 tun->align = NET_SKB_PAD;
1786 tun->filter_attached = false;
1787 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
1788
1789 tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats);
1790 if (!tun->pcpu_stats) {
1791 err = -ENOMEM;
1792 goto err_free_dev;
1793 }
1794
1795 spin_lock_init(&tun->lock);
1796
1797 err = security_tun_dev_alloc_security(&tun->security);
1798 if (err < 0)
1799 goto err_free_stat;
1800
1801 tun_net_init(dev);
1802 tun_flow_init(tun);
1803
1804 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1805 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
1806 NETIF_F_HW_VLAN_STAG_TX;
1807 dev->features = dev->hw_features | NETIF_F_LLTX;
1808 dev->vlan_features = dev->features &
1809 ~(NETIF_F_HW_VLAN_CTAG_TX |
1810 NETIF_F_HW_VLAN_STAG_TX);
1811
1812 INIT_LIST_HEAD(&tun->disabled);
1813 err = tun_attach(tun, file, false);
1814 if (err < 0)
1815 goto err_free_flow;
1816
1817 err = register_netdevice(tun->dev);
1818 if (err < 0)
1819 goto err_detach;
1820 }
1821
1822 netif_carrier_on(tun->dev);
1823
1824 tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1825
1826 tun->flags = (tun->flags & ~TUN_FEATURES) |
1827 (ifr->ifr_flags & TUN_FEATURES);
1828
1829 /* Make sure persistent devices do not get stuck in
1830 * xoff state.
1831 */
1832 if (netif_running(tun->dev))
1833 netif_tx_wake_all_queues(tun->dev);
1834
1835 strcpy(ifr->ifr_name, tun->dev->name);
1836 return 0;
1837
1838 err_detach:
1839 tun_detach_all(dev);
1840 err_free_flow:
1841 tun_flow_uninit(tun);
1842 security_tun_dev_free_security(tun->security);
1843 err_free_stat:
1844 free_percpu(tun->pcpu_stats);
1845 err_free_dev:
1846 free_netdev(dev);
1847 return err;
1848 }
1849
1850 static void tun_get_iff(struct net *net, struct tun_struct *tun,
1851 struct ifreq *ifr)
1852 {
1853 tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1854
1855 strcpy(ifr->ifr_name, tun->dev->name);
1856
1857 ifr->ifr_flags = tun_flags(tun);
1858
1859 }
1860
1861 /* This is like a cut-down ethtool ops, except done via tun fd so no
1862 * privs required. */
1863 static int set_offload(struct tun_struct *tun, unsigned long arg)
1864 {
1865 netdev_features_t features = 0;
1866
1867 if (arg & TUN_F_CSUM) {
1868 features |= NETIF_F_HW_CSUM;
1869 arg &= ~TUN_F_CSUM;
1870
1871 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1872 if (arg & TUN_F_TSO_ECN) {
1873 features |= NETIF_F_TSO_ECN;
1874 arg &= ~TUN_F_TSO_ECN;
1875 }
1876 if (arg & TUN_F_TSO4)
1877 features |= NETIF_F_TSO;
1878 if (arg & TUN_F_TSO6)
1879 features |= NETIF_F_TSO6;
1880 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1881 }
1882
1883 if (arg & TUN_F_UFO) {
1884 features |= NETIF_F_UFO;
1885 arg &= ~TUN_F_UFO;
1886 }
1887 }
1888
1889 /* This gives the user a way to test for new features in future by
1890 * trying to set them. */
1891 if (arg)
1892 return -EINVAL;
1893
1894 tun->set_features = features;
1895 netdev_update_features(tun->dev);
1896
1897 return 0;
1898 }
1899
1900 static void tun_detach_filter(struct tun_struct *tun, int n)
1901 {
1902 int i;
1903 struct tun_file *tfile;
1904
1905 for (i = 0; i < n; i++) {
1906 tfile = rtnl_dereference(tun->tfiles[i]);
1907 lock_sock(tfile->socket.sk);
1908 sk_detach_filter(tfile->socket.sk);
1909 release_sock(tfile->socket.sk);
1910 }
1911
1912 tun->filter_attached = false;
1913 }
1914
1915 static int tun_attach_filter(struct tun_struct *tun)
1916 {
1917 int i, ret = 0;
1918 struct tun_file *tfile;
1919
1920 for (i = 0; i < tun->numqueues; i++) {
1921 tfile = rtnl_dereference(tun->tfiles[i]);
1922 lock_sock(tfile->socket.sk);
1923 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
1924 release_sock(tfile->socket.sk);
1925 if (ret) {
1926 tun_detach_filter(tun, i);
1927 return ret;
1928 }
1929 }
1930
1931 tun->filter_attached = true;
1932 return ret;
1933 }
1934
1935 static void tun_set_sndbuf(struct tun_struct *tun)
1936 {
1937 struct tun_file *tfile;
1938 int i;
1939
1940 for (i = 0; i < tun->numqueues; i++) {
1941 tfile = rtnl_dereference(tun->tfiles[i]);
1942 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
1943 }
1944 }
1945
1946 static int tun_set_queue(struct file *file, struct ifreq *ifr)
1947 {
1948 struct tun_file *tfile = file->private_data;
1949 struct tun_struct *tun;
1950 int ret = 0;
1951
1952 rtnl_lock();
1953
1954 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
1955 tun = tfile->detached;
1956 if (!tun) {
1957 ret = -EINVAL;
1958 goto unlock;
1959 }
1960 ret = security_tun_dev_attach_queue(tun->security);
1961 if (ret < 0)
1962 goto unlock;
1963 ret = tun_attach(tun, file, false);
1964 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
1965 tun = rtnl_dereference(tfile->tun);
1966 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
1967 ret = -EINVAL;
1968 else
1969 __tun_detach(tfile, false);
1970 } else
1971 ret = -EINVAL;
1972
1973 unlock:
1974 rtnl_unlock();
1975 return ret;
1976 }
1977
1978 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1979 unsigned long arg, int ifreq_len)
1980 {
1981 struct tun_file *tfile = file->private_data;
1982 struct tun_struct *tun;
1983 void __user* argp = (void __user*)arg;
1984 struct ifreq ifr;
1985 kuid_t owner;
1986 kgid_t group;
1987 int sndbuf;
1988 int vnet_hdr_sz;
1989 unsigned int ifindex;
1990 int le;
1991 int ret;
1992
1993 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == SOCK_IOC_TYPE) {
1994 if (copy_from_user(&ifr, argp, ifreq_len))
1995 return -EFAULT;
1996 } else {
1997 memset(&ifr, 0, sizeof(ifr));
1998 }
1999 if (cmd == TUNGETFEATURES) {
2000 /* Currently this just means: "what IFF flags are valid?".
2001 * This is needed because we never checked for invalid flags on
2002 * TUNSETIFF.
2003 */
2004 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
2005 (unsigned int __user*)argp);
2006 } else if (cmd == TUNSETQUEUE)
2007 return tun_set_queue(file, &ifr);
2008
2009 ret = 0;
2010 rtnl_lock();
2011
2012 tun = __tun_get(tfile);
2013 if (cmd == TUNSETIFF) {
2014 ret = -EEXIST;
2015 if (tun)
2016 goto unlock;
2017
2018 ifr.ifr_name[IFNAMSIZ-1] = '\0';
2019
2020 ret = tun_set_iff(sock_net(&tfile->sk), file, &ifr);
2021
2022 if (ret)
2023 goto unlock;
2024
2025 if (copy_to_user(argp, &ifr, ifreq_len))
2026 ret = -EFAULT;
2027 goto unlock;
2028 }
2029 if (cmd == TUNSETIFINDEX) {
2030 ret = -EPERM;
2031 if (tun)
2032 goto unlock;
2033
2034 ret = -EFAULT;
2035 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
2036 goto unlock;
2037
2038 ret = 0;
2039 tfile->ifindex = ifindex;
2040 goto unlock;
2041 }
2042
2043 ret = -EBADFD;
2044 if (!tun)
2045 goto unlock;
2046
2047 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
2048
2049 ret = 0;
2050 switch (cmd) {
2051 case TUNGETIFF:
2052 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2053
2054 if (tfile->detached)
2055 ifr.ifr_flags |= IFF_DETACH_QUEUE;
2056 if (!tfile->socket.sk->sk_filter)
2057 ifr.ifr_flags |= IFF_NOFILTER;
2058
2059 if (copy_to_user(argp, &ifr, ifreq_len))
2060 ret = -EFAULT;
2061 break;
2062
2063 case TUNSETNOCSUM:
2064 /* Disable/Enable checksum */
2065
2066 /* [unimplemented] */
2067 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
2068 arg ? "disabled" : "enabled");
2069 break;
2070
2071 case TUNSETPERSIST:
2072 /* Disable/Enable persist mode. Keep an extra reference to the
2073 * module to prevent the module being unprobed.
2074 */
2075 if (arg && !(tun->flags & IFF_PERSIST)) {
2076 tun->flags |= IFF_PERSIST;
2077 __module_get(THIS_MODULE);
2078 }
2079 if (!arg && (tun->flags & IFF_PERSIST)) {
2080 tun->flags &= ~IFF_PERSIST;
2081 module_put(THIS_MODULE);
2082 }
2083
2084 tun_debug(KERN_INFO, tun, "persist %s\n",
2085 arg ? "enabled" : "disabled");
2086 break;
2087
2088 case TUNSETOWNER:
2089 /* Set owner of the device */
2090 owner = make_kuid(current_user_ns(), arg);
2091 if (!uid_valid(owner)) {
2092 ret = -EINVAL;
2093 break;
2094 }
2095 tun->owner = owner;
2096 tun_debug(KERN_INFO, tun, "owner set to %u\n",
2097 from_kuid(&init_user_ns, tun->owner));
2098 break;
2099
2100 case TUNSETGROUP:
2101 /* Set group of the device */
2102 group = make_kgid(current_user_ns(), arg);
2103 if (!gid_valid(group)) {
2104 ret = -EINVAL;
2105 break;
2106 }
2107 tun->group = group;
2108 tun_debug(KERN_INFO, tun, "group set to %u\n",
2109 from_kgid(&init_user_ns, tun->group));
2110 break;
2111
2112 case TUNSETLINK:
2113 /* Only allow setting the type when the interface is down */
2114 if (tun->dev->flags & IFF_UP) {
2115 tun_debug(KERN_INFO, tun,
2116 "Linktype set failed because interface is up\n");
2117 ret = -EBUSY;
2118 } else {
2119 tun->dev->type = (int) arg;
2120 tun_debug(KERN_INFO, tun, "linktype set to %d\n",
2121 tun->dev->type);
2122 ret = 0;
2123 }
2124 break;
2125
2126 #ifdef TUN_DEBUG
2127 case TUNSETDEBUG:
2128 tun->debug = arg;
2129 break;
2130 #endif
2131 case TUNSETOFFLOAD:
2132 ret = set_offload(tun, arg);
2133 break;
2134
2135 case TUNSETTXFILTER:
2136 /* Can be set only for TAPs */
2137 ret = -EINVAL;
2138 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2139 break;
2140 ret = update_filter(&tun->txflt, (void __user *)arg);
2141 break;
2142
2143 case SIOCGIFHWADDR:
2144 /* Get hw address */
2145 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
2146 ifr.ifr_hwaddr.sa_family = tun->dev->type;
2147 if (copy_to_user(argp, &ifr, ifreq_len))
2148 ret = -EFAULT;
2149 break;
2150
2151 case SIOCSIFHWADDR:
2152 /* Set hw address */
2153 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
2154 ifr.ifr_hwaddr.sa_data);
2155
2156 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
2157 break;
2158
2159 case TUNGETSNDBUF:
2160 sndbuf = tfile->socket.sk->sk_sndbuf;
2161 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
2162 ret = -EFAULT;
2163 break;
2164
2165 case TUNSETSNDBUF:
2166 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
2167 ret = -EFAULT;
2168 break;
2169 }
2170
2171 tun->sndbuf = sndbuf;
2172 tun_set_sndbuf(tun);
2173 break;
2174
2175 case TUNGETVNETHDRSZ:
2176 vnet_hdr_sz = tun->vnet_hdr_sz;
2177 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
2178 ret = -EFAULT;
2179 break;
2180
2181 case TUNSETVNETHDRSZ:
2182 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
2183 ret = -EFAULT;
2184 break;
2185 }
2186 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
2187 ret = -EINVAL;
2188 break;
2189 }
2190
2191 tun->vnet_hdr_sz = vnet_hdr_sz;
2192 break;
2193
2194 case TUNGETVNETLE:
2195 le = !!(tun->flags & TUN_VNET_LE);
2196 if (put_user(le, (int __user *)argp))
2197 ret = -EFAULT;
2198 break;
2199
2200 case TUNSETVNETLE:
2201 if (get_user(le, (int __user *)argp)) {
2202 ret = -EFAULT;
2203 break;
2204 }
2205 if (le)
2206 tun->flags |= TUN_VNET_LE;
2207 else
2208 tun->flags &= ~TUN_VNET_LE;
2209 break;
2210
2211 case TUNGETVNETBE:
2212 ret = tun_get_vnet_be(tun, argp);
2213 break;
2214
2215 case TUNSETVNETBE:
2216 ret = tun_set_vnet_be(tun, argp);
2217 break;
2218
2219 case TUNATTACHFILTER:
2220 /* Can be set only for TAPs */
2221 ret = -EINVAL;
2222 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2223 break;
2224 ret = -EFAULT;
2225 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
2226 break;
2227
2228 ret = tun_attach_filter(tun);
2229 break;
2230
2231 case TUNDETACHFILTER:
2232 /* Can be set only for TAPs */
2233 ret = -EINVAL;
2234 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2235 break;
2236 ret = 0;
2237 tun_detach_filter(tun, tun->numqueues);
2238 break;
2239
2240 case TUNGETFILTER:
2241 ret = -EINVAL;
2242 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2243 break;
2244 ret = -EFAULT;
2245 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
2246 break;
2247 ret = 0;
2248 break;
2249
2250 default:
2251 ret = -EINVAL;
2252 break;
2253 }
2254
2255 unlock:
2256 rtnl_unlock();
2257 if (tun)
2258 tun_put(tun);
2259 return ret;
2260 }
2261
2262 static long tun_chr_ioctl(struct file *file,
2263 unsigned int cmd, unsigned long arg)
2264 {
2265 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
2266 }
2267
2268 #ifdef CONFIG_COMPAT
2269 static long tun_chr_compat_ioctl(struct file *file,
2270 unsigned int cmd, unsigned long arg)
2271 {
2272 switch (cmd) {
2273 case TUNSETIFF:
2274 case TUNGETIFF:
2275 case TUNSETTXFILTER:
2276 case TUNGETSNDBUF:
2277 case TUNSETSNDBUF:
2278 case SIOCGIFHWADDR:
2279 case SIOCSIFHWADDR:
2280 arg = (unsigned long)compat_ptr(arg);
2281 break;
2282 default:
2283 arg = (compat_ulong_t)arg;
2284 break;
2285 }
2286
2287 /*
2288 * compat_ifreq is shorter than ifreq, so we must not access beyond
2289 * the end of that structure. All fields that are used in this
2290 * driver are compatible though, we don't need to convert the
2291 * contents.
2292 */
2293 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
2294 }
2295 #endif /* CONFIG_COMPAT */
2296
2297 static int tun_chr_fasync(int fd, struct file *file, int on)
2298 {
2299 struct tun_file *tfile = file->private_data;
2300 int ret;
2301
2302 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
2303 goto out;
2304
2305 if (on) {
2306 __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
2307 tfile->flags |= TUN_FASYNC;
2308 } else
2309 tfile->flags &= ~TUN_FASYNC;
2310 ret = 0;
2311 out:
2312 return ret;
2313 }
2314
2315 static int tun_chr_open(struct inode *inode, struct file * file)
2316 {
2317 struct net *net = current->nsproxy->net_ns;
2318 struct tun_file *tfile;
2319
2320 DBG1(KERN_INFO, "tunX: tun_chr_open\n");
2321
2322 tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
2323 &tun_proto, 0);
2324 if (!tfile)
2325 return -ENOMEM;
2326 RCU_INIT_POINTER(tfile->tun, NULL);
2327 tfile->flags = 0;
2328 tfile->ifindex = 0;
2329
2330 init_waitqueue_head(&tfile->wq.wait);
2331 RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq);
2332
2333 tfile->socket.file = file;
2334 tfile->socket.ops = &tun_socket_ops;
2335
2336 sock_init_data(&tfile->socket, &tfile->sk);
2337
2338 tfile->sk.sk_write_space = tun_sock_write_space;
2339 tfile->sk.sk_sndbuf = INT_MAX;
2340
2341 file->private_data = tfile;
2342 INIT_LIST_HEAD(&tfile->next);
2343
2344 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
2345
2346 return 0;
2347 }
2348
2349 static int tun_chr_close(struct inode *inode, struct file *file)
2350 {
2351 struct tun_file *tfile = file->private_data;
2352
2353 tun_detach(tfile, true);
2354
2355 return 0;
2356 }
2357
2358 #ifdef CONFIG_PROC_FS
2359 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *f)
2360 {
2361 struct tun_struct *tun;
2362 struct ifreq ifr;
2363
2364 memset(&ifr, 0, sizeof(ifr));
2365
2366 rtnl_lock();
2367 tun = tun_get(f);
2368 if (tun)
2369 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2370 rtnl_unlock();
2371
2372 if (tun)
2373 tun_put(tun);
2374
2375 seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
2376 }
2377 #endif
2378
2379 static const struct file_operations tun_fops = {
2380 .owner = THIS_MODULE,
2381 .llseek = no_llseek,
2382 .read_iter = tun_chr_read_iter,
2383 .write_iter = tun_chr_write_iter,
2384 .poll = tun_chr_poll,
2385 .unlocked_ioctl = tun_chr_ioctl,
2386 #ifdef CONFIG_COMPAT
2387 .compat_ioctl = tun_chr_compat_ioctl,
2388 #endif
2389 .open = tun_chr_open,
2390 .release = tun_chr_close,
2391 .fasync = tun_chr_fasync,
2392 #ifdef CONFIG_PROC_FS
2393 .show_fdinfo = tun_chr_show_fdinfo,
2394 #endif
2395 };
2396
2397 static struct miscdevice tun_miscdev = {
2398 .minor = TUN_MINOR,
2399 .name = "tun",
2400 .nodename = "net/tun",
2401 .fops = &tun_fops,
2402 };
2403
2404 /* ethtool interface */
2405
2406 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
2407 {
2408 cmd->supported = 0;
2409 cmd->advertising = 0;
2410 ethtool_cmd_speed_set(cmd, SPEED_10);
2411 cmd->duplex = DUPLEX_FULL;
2412 cmd->port = PORT_TP;
2413 cmd->phy_address = 0;
2414 cmd->transceiver = XCVR_INTERNAL;
2415 cmd->autoneg = AUTONEG_DISABLE;
2416 cmd->maxtxpkt = 0;
2417 cmd->maxrxpkt = 0;
2418 return 0;
2419 }
2420
2421 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
2422 {
2423 struct tun_struct *tun = netdev_priv(dev);
2424
2425 strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
2426 strlcpy(info->version, DRV_VERSION, sizeof(info->version));
2427
2428 switch (tun->flags & TUN_TYPE_MASK) {
2429 case IFF_TUN:
2430 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
2431 break;
2432 case IFF_TAP:
2433 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
2434 break;
2435 }
2436 }
2437
2438 static u32 tun_get_msglevel(struct net_device *dev)
2439 {
2440 #ifdef TUN_DEBUG
2441 struct tun_struct *tun = netdev_priv(dev);
2442 return tun->debug;
2443 #else
2444 return -EOPNOTSUPP;
2445 #endif
2446 }
2447
2448 static void tun_set_msglevel(struct net_device *dev, u32 value)
2449 {
2450 #ifdef TUN_DEBUG
2451 struct tun_struct *tun = netdev_priv(dev);
2452 tun->debug = value;
2453 #endif
2454 }
2455
2456 static const struct ethtool_ops tun_ethtool_ops = {
2457 .get_settings = tun_get_settings,
2458 .get_drvinfo = tun_get_drvinfo,
2459 .get_msglevel = tun_get_msglevel,
2460 .set_msglevel = tun_set_msglevel,
2461 .get_link = ethtool_op_get_link,
2462 .get_ts_info = ethtool_op_get_ts_info,
2463 };
2464
2465 static int tun_queue_resize(struct tun_struct *tun)
2466 {
2467 struct net_device *dev = tun->dev;
2468 struct tun_file *tfile;
2469 struct skb_array **arrays;
2470 int n = tun->numqueues + tun->numdisabled;
2471 int ret, i;
2472
2473 arrays = kmalloc(sizeof *arrays * n, GFP_KERNEL);
2474 if (!arrays)
2475 return -ENOMEM;
2476
2477 for (i = 0; i < tun->numqueues; i++) {
2478 tfile = rtnl_dereference(tun->tfiles[i]);
2479 arrays[i] = &tfile->tx_array;
2480 }
2481 list_for_each_entry(tfile, &tun->disabled, next)
2482 arrays[i++] = &tfile->tx_array;
2483
2484 ret = skb_array_resize_multiple(arrays, n,
2485 dev->tx_queue_len, GFP_KERNEL);
2486
2487 kfree(arrays);
2488 return ret;
2489 }
2490
2491 static int tun_device_event(struct notifier_block *unused,
2492 unsigned long event, void *ptr)
2493 {
2494 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
2495 struct tun_struct *tun = netdev_priv(dev);
2496
2497 if (dev->rtnl_link_ops != &tun_link_ops)
2498 return NOTIFY_DONE;
2499
2500 switch (event) {
2501 case NETDEV_CHANGE_TX_QUEUE_LEN:
2502 if (tun_queue_resize(tun))
2503 return NOTIFY_BAD;
2504 break;
2505 default:
2506 break;
2507 }
2508
2509 return NOTIFY_DONE;
2510 }
2511
2512 static struct notifier_block tun_notifier_block __read_mostly = {
2513 .notifier_call = tun_device_event,
2514 };
2515
2516 static int __init tun_init(void)
2517 {
2518 int ret = 0;
2519
2520 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
2521 pr_info("%s\n", DRV_COPYRIGHT);
2522
2523 ret = rtnl_link_register(&tun_link_ops);
2524 if (ret) {
2525 pr_err("Can't register link_ops\n");
2526 goto err_linkops;
2527 }
2528
2529 ret = misc_register(&tun_miscdev);
2530 if (ret) {
2531 pr_err("Can't register misc device %d\n", TUN_MINOR);
2532 goto err_misc;
2533 }
2534
2535 register_netdevice_notifier(&tun_notifier_block);
2536 return 0;
2537 err_misc:
2538 rtnl_link_unregister(&tun_link_ops);
2539 err_linkops:
2540 return ret;
2541 }
2542
2543 static void tun_cleanup(void)
2544 {
2545 misc_deregister(&tun_miscdev);
2546 rtnl_link_unregister(&tun_link_ops);
2547 unregister_netdevice_notifier(&tun_notifier_block);
2548 }
2549
2550 /* Get an underlying socket object from tun file. Returns error unless file is
2551 * attached to a device. The returned object works like a packet socket, it
2552 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
2553 * holding a reference to the file for as long as the socket is in use. */
2554 struct socket *tun_get_socket(struct file *file)
2555 {
2556 struct tun_file *tfile;
2557 if (file->f_op != &tun_fops)
2558 return ERR_PTR(-EINVAL);
2559 tfile = file->private_data;
2560 if (!tfile)
2561 return ERR_PTR(-EBADFD);
2562 return &tfile->socket;
2563 }
2564 EXPORT_SYMBOL_GPL(tun_get_socket);
2565
2566 module_init(tun_init);
2567 module_exit(tun_cleanup);
2568 MODULE_DESCRIPTION(DRV_DESCRIPTION);
2569 MODULE_AUTHOR(DRV_COPYRIGHT);
2570 MODULE_LICENSE("GPL");
2571 MODULE_ALIAS_MISCDEV(TUN_MINOR);
2572 MODULE_ALIAS("devname:net/tun");
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