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Merge tag 'chrome-platform-for-linus-4.13' of git://git.kernel.org/pub/scm/linux...
[linux/fpc-iii.git] / drivers / net / tun.c
blob3d4c24572ecdcda8ffdd47070ce75dcb625441da
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/sched/signal.h>
48 #include <linux/major.h>
49 #include <linux/slab.h>
50 #include <linux/poll.h>
51 #include <linux/fcntl.h>
52 #include <linux/init.h>
53 #include <linux/skbuff.h>
54 #include <linux/netdevice.h>
55 #include <linux/etherdevice.h>
56 #include <linux/miscdevice.h>
57 #include <linux/ethtool.h>
58 #include <linux/rtnetlink.h>
59 #include <linux/compat.h>
60 #include <linux/if.h>
61 #include <linux/if_arp.h>
62 #include <linux/if_ether.h>
63 #include <linux/if_tun.h>
64 #include <linux/if_vlan.h>
65 #include <linux/crc32.h>
66 #include <linux/nsproxy.h>
67 #include <linux/virtio_net.h>
68 #include <linux/rcupdate.h>
69 #include <net/net_namespace.h>
70 #include <net/netns/generic.h>
71 #include <net/rtnetlink.h>
72 #include <net/sock.h>
73 #include <linux/seq_file.h>
74 #include <linux/uio.h>
75 #include <linux/skb_array.h>
76
77 #include <linux/uaccess.h>
78
79 /* Uncomment to enable debugging */
80 /* #define TUN_DEBUG 1 */
81
82 #ifdef TUN_DEBUG
83 static int debug;
84
85 #define tun_debug(level, tun, fmt, args...) \
86 do { \
87 if (tun->debug) \
88 netdev_printk(level, tun->dev, fmt, ##args); \
89 } while (0)
90 #define DBG1(level, fmt, args...) \
91 do { \
92 if (debug == 2) \
93 printk(level fmt, ##args); \
94 } while (0)
95 #else
96 #define tun_debug(level, tun, fmt, args...) \
97 do { \
98 if (0) \
99 netdev_printk(level, tun->dev, fmt, ##args); \
100 } while (0)
101 #define DBG1(level, fmt, args...) \
102 do { \
103 if (0) \
104 printk(level fmt, ##args); \
105 } while (0)
106 #endif
107
108 /* TUN device flags */
109
110 /* IFF_ATTACH_QUEUE is never stored in device flags,
111 * overload it to mean fasync when stored there.
112 */
113 #define TUN_FASYNC IFF_ATTACH_QUEUE
114 /* High bits in flags field are unused. */
115 #define TUN_VNET_LE 0x80000000
116 #define TUN_VNET_BE 0x40000000
117
118 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
119 IFF_MULTI_QUEUE)
120 #define GOODCOPY_LEN 128
121
122 #define FLT_EXACT_COUNT 8
123 struct tap_filter {
124 unsigned int count; /* Number of addrs. Zero means disabled */
125 u32 mask[2]; /* Mask of the hashed addrs */
126 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
127 };
128
129 /* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
130 * to max number of VCPUs in guest. */
131 #define MAX_TAP_QUEUES 256
132 #define MAX_TAP_FLOWS 4096
133
134 #define TUN_FLOW_EXPIRE (3 * HZ)
135
136 struct tun_pcpu_stats {
137 u64 rx_packets;
138 u64 rx_bytes;
139 u64 tx_packets;
140 u64 tx_bytes;
141 struct u64_stats_sync syncp;
142 u32 rx_dropped;
143 u32 tx_dropped;
144 u32 rx_frame_errors;
145 };
146
147 /* A tun_file connects an open character device to a tuntap netdevice. It
148 * also contains all socket related structures (except sock_fprog and tap_filter)
149 * to serve as one transmit queue for tuntap device. The sock_fprog and
150 * tap_filter were kept in tun_struct since they were used for filtering for the
151 * netdevice not for a specific queue (at least I didn't see the requirement for
152 * this).
153 *
154 * RCU usage:
155 * The tun_file and tun_struct are loosely coupled, the pointer from one to the
156 * other can only be read while rcu_read_lock or rtnl_lock is held.
157 */
158 struct tun_file {
159 struct sock sk;
160 struct socket socket;
161 struct socket_wq wq;
162 struct tun_struct __rcu *tun;
163 struct fasync_struct *fasync;
164 /* only used for fasnyc */
165 unsigned int flags;
166 union {
167 u16 queue_index;
168 unsigned int ifindex;
169 };
170 struct list_head next;
171 struct tun_struct *detached;
172 struct skb_array tx_array;
173 };
174
175 struct tun_flow_entry {
176 struct hlist_node hash_link;
177 struct rcu_head rcu;
178 struct tun_struct *tun;
179
180 u32 rxhash;
181 u32 rps_rxhash;
182 int queue_index;
183 unsigned long updated;
184 };
185
186 #define TUN_NUM_FLOW_ENTRIES 1024
187
188 /* Since the socket were moved to tun_file, to preserve the behavior of persist
189 * device, socket filter, sndbuf and vnet header size were restore when the
190 * file were attached to a persist device.
191 */
192 struct tun_struct {
193 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES];
194 unsigned int numqueues;
195 unsigned int flags;
196 kuid_t owner;
197 kgid_t group;
198
199 struct net_device *dev;
200 netdev_features_t set_features;
201 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
202 NETIF_F_TSO6|NETIF_F_UFO)
203
204 int align;
205 int vnet_hdr_sz;
206 int sndbuf;
207 struct tap_filter txflt;
208 struct sock_fprog fprog;
209 /* protected by rtnl lock */
210 bool filter_attached;
211 #ifdef TUN_DEBUG
212 int debug;
213 #endif
214 spinlock_t lock;
215 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
216 struct timer_list flow_gc_timer;
217 unsigned long ageing_time;
218 unsigned int numdisabled;
219 struct list_head disabled;
220 void *security;
221 u32 flow_count;
222 u32 rx_batched;
223 struct tun_pcpu_stats __percpu *pcpu_stats;
224 };
225
226 #ifdef CONFIG_TUN_VNET_CROSS_LE
227 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
228 {
229 return tun->flags & TUN_VNET_BE ? false :
230 virtio_legacy_is_little_endian();
231 }
232
233 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
234 {
235 int be = !!(tun->flags & TUN_VNET_BE);
236
237 if (put_user(be, argp))
238 return -EFAULT;
239
240 return 0;
241 }
242
243 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
244 {
245 int be;
246
247 if (get_user(be, argp))
248 return -EFAULT;
249
250 if (be)
251 tun->flags |= TUN_VNET_BE;
252 else
253 tun->flags &= ~TUN_VNET_BE;
254
255 return 0;
256 }
257 #else
258 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
259 {
260 return virtio_legacy_is_little_endian();
261 }
262
263 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
264 {
265 return -EINVAL;
266 }
267
268 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
269 {
270 return -EINVAL;
271 }
272 #endif /* CONFIG_TUN_VNET_CROSS_LE */
273
274 static inline bool tun_is_little_endian(struct tun_struct *tun)
275 {
276 return tun->flags & TUN_VNET_LE ||
277 tun_legacy_is_little_endian(tun);
278 }
279
280 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
281 {
282 return __virtio16_to_cpu(tun_is_little_endian(tun), val);
283 }
284
285 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
286 {
287 return __cpu_to_virtio16(tun_is_little_endian(tun), val);
288 }
289
290 static inline u32 tun_hashfn(u32 rxhash)
291 {
292 return rxhash & 0x3ff;
293 }
294
295 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
296 {
297 struct tun_flow_entry *e;
298
299 hlist_for_each_entry_rcu(e, head, hash_link) {
300 if (e->rxhash == rxhash)
301 return e;
302 }
303 return NULL;
304 }
305
306 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
307 struct hlist_head *head,
308 u32 rxhash, u16 queue_index)
309 {
310 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
311
312 if (e) {
313 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
314 rxhash, queue_index);
315 e->updated = jiffies;
316 e->rxhash = rxhash;
317 e->rps_rxhash = 0;
318 e->queue_index = queue_index;
319 e->tun = tun;
320 hlist_add_head_rcu(&e->hash_link, head);
321 ++tun->flow_count;
322 }
323 return e;
324 }
325
326 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
327 {
328 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
329 e->rxhash, e->queue_index);
330 hlist_del_rcu(&e->hash_link);
331 kfree_rcu(e, rcu);
332 --tun->flow_count;
333 }
334
335 static void tun_flow_flush(struct tun_struct *tun)
336 {
337 int i;
338
339 spin_lock_bh(&tun->lock);
340 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
341 struct tun_flow_entry *e;
342 struct hlist_node *n;
343
344 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
345 tun_flow_delete(tun, e);
346 }
347 spin_unlock_bh(&tun->lock);
348 }
349
350 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
351 {
352 int i;
353
354 spin_lock_bh(&tun->lock);
355 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
356 struct tun_flow_entry *e;
357 struct hlist_node *n;
358
359 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
360 if (e->queue_index == queue_index)
361 tun_flow_delete(tun, e);
362 }
363 }
364 spin_unlock_bh(&tun->lock);
365 }
366
367 static void tun_flow_cleanup(unsigned long data)
368 {
369 struct tun_struct *tun = (struct tun_struct *)data;
370 unsigned long delay = tun->ageing_time;
371 unsigned long next_timer = jiffies + delay;
372 unsigned long count = 0;
373 int i;
374
375 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
376
377 spin_lock_bh(&tun->lock);
378 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
379 struct tun_flow_entry *e;
380 struct hlist_node *n;
381
382 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
383 unsigned long this_timer;
384 count++;
385 this_timer = e->updated + delay;
386 if (time_before_eq(this_timer, jiffies))
387 tun_flow_delete(tun, e);
388 else if (time_before(this_timer, next_timer))
389 next_timer = this_timer;
390 }
391 }
392
393 if (count)
394 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
395 spin_unlock_bh(&tun->lock);
396 }
397
398 static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
399 struct tun_file *tfile)
400 {
401 struct hlist_head *head;
402 struct tun_flow_entry *e;
403 unsigned long delay = tun->ageing_time;
404 u16 queue_index = tfile->queue_index;
405
406 if (!rxhash)
407 return;
408 else
409 head = &tun->flows[tun_hashfn(rxhash)];
410
411 rcu_read_lock();
412
413 /* We may get a very small possibility of OOO during switching, not
414 * worth to optimize.*/
415 if (tun->numqueues == 1 || tfile->detached)
416 goto unlock;
417
418 e = tun_flow_find(head, rxhash);
419 if (likely(e)) {
420 /* TODO: keep queueing to old queue until it's empty? */
421 e->queue_index = queue_index;
422 e->updated = jiffies;
423 sock_rps_record_flow_hash(e->rps_rxhash);
424 } else {
425 spin_lock_bh(&tun->lock);
426 if (!tun_flow_find(head, rxhash) &&
427 tun->flow_count < MAX_TAP_FLOWS)
428 tun_flow_create(tun, head, rxhash, queue_index);
429
430 if (!timer_pending(&tun->flow_gc_timer))
431 mod_timer(&tun->flow_gc_timer,
432 round_jiffies_up(jiffies + delay));
433 spin_unlock_bh(&tun->lock);
434 }
435
436 unlock:
437 rcu_read_unlock();
438 }
439
440 /**
441 * Save the hash received in the stack receive path and update the
442 * flow_hash table accordingly.
443 */
444 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
445 {
446 if (unlikely(e->rps_rxhash != hash))
447 e->rps_rxhash = hash;
448 }
449
450 /* We try to identify a flow through its rxhash first. The reason that
451 * we do not check rxq no. is because some cards(e.g 82599), chooses
452 * the rxq based on the txq where the last packet of the flow comes. As
453 * the userspace application move between processors, we may get a
454 * different rxq no. here. If we could not get rxhash, then we would
455 * hope the rxq no. may help here.
456 */
457 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
458 void *accel_priv, select_queue_fallback_t fallback)
459 {
460 struct tun_struct *tun = netdev_priv(dev);
461 struct tun_flow_entry *e;
462 u32 txq = 0;
463 u32 numqueues = 0;
464
465 rcu_read_lock();
466 numqueues = ACCESS_ONCE(tun->numqueues);
467
468 txq = __skb_get_hash_symmetric(skb);
469 if (txq) {
470 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
471 if (e) {
472 tun_flow_save_rps_rxhash(e, txq);
473 txq = e->queue_index;
474 } else
475 /* use multiply and shift instead of expensive divide */
476 txq = ((u64)txq * numqueues) >> 32;
477 } else if (likely(skb_rx_queue_recorded(skb))) {
478 txq = skb_get_rx_queue(skb);
479 while (unlikely(txq >= numqueues))
480 txq -= numqueues;
481 }
482
483 rcu_read_unlock();
484 return txq;
485 }
486
487 static inline bool tun_not_capable(struct tun_struct *tun)
488 {
489 const struct cred *cred = current_cred();
490 struct net *net = dev_net(tun->dev);
491
492 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
493 (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
494 !ns_capable(net->user_ns, CAP_NET_ADMIN);
495 }
496
497 static void tun_set_real_num_queues(struct tun_struct *tun)
498 {
499 netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
500 netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
501 }
502
503 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
504 {
505 tfile->detached = tun;
506 list_add_tail(&tfile->next, &tun->disabled);
507 ++tun->numdisabled;
508 }
509
510 static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
511 {
512 struct tun_struct *tun = tfile->detached;
513
514 tfile->detached = NULL;
515 list_del_init(&tfile->next);
516 --tun->numdisabled;
517 return tun;
518 }
519
520 static void tun_queue_purge(struct tun_file *tfile)
521 {
522 struct sk_buff *skb;
523
524 while ((skb = skb_array_consume(&tfile->tx_array)) != NULL)
525 kfree_skb(skb);
526
527 skb_queue_purge(&tfile->sk.sk_write_queue);
528 skb_queue_purge(&tfile->sk.sk_error_queue);
529 }
530
531 static void __tun_detach(struct tun_file *tfile, bool clean)
532 {
533 struct tun_file *ntfile;
534 struct tun_struct *tun;
535
536 tun = rtnl_dereference(tfile->tun);
537
538 if (tun && !tfile->detached) {
539 u16 index = tfile->queue_index;
540 BUG_ON(index >= tun->numqueues);
541
542 rcu_assign_pointer(tun->tfiles[index],
543 tun->tfiles[tun->numqueues - 1]);
544 ntfile = rtnl_dereference(tun->tfiles[index]);
545 ntfile->queue_index = index;
546
547 --tun->numqueues;
548 if (clean) {
549 RCU_INIT_POINTER(tfile->tun, NULL);
550 sock_put(&tfile->sk);
551 } else
552 tun_disable_queue(tun, tfile);
553
554 synchronize_net();
555 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
556 /* Drop read queue */
557 tun_queue_purge(tfile);
558 tun_set_real_num_queues(tun);
559 } else if (tfile->detached && clean) {
560 tun = tun_enable_queue(tfile);
561 sock_put(&tfile->sk);
562 }
563
564 if (clean) {
565 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
566 netif_carrier_off(tun->dev);
567
568 if (!(tun->flags & IFF_PERSIST) &&
569 tun->dev->reg_state == NETREG_REGISTERED)
570 unregister_netdevice(tun->dev);
571 }
572 if (tun)
573 skb_array_cleanup(&tfile->tx_array);
574 sock_put(&tfile->sk);
575 }
576 }
577
578 static void tun_detach(struct tun_file *tfile, bool clean)
579 {
580 rtnl_lock();
581 __tun_detach(tfile, clean);
582 rtnl_unlock();
583 }
584
585 static void tun_detach_all(struct net_device *dev)
586 {
587 struct tun_struct *tun = netdev_priv(dev);
588 struct tun_file *tfile, *tmp;
589 int i, n = tun->numqueues;
590
591 for (i = 0; i < n; i++) {
592 tfile = rtnl_dereference(tun->tfiles[i]);
593 BUG_ON(!tfile);
594 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
595 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
596 RCU_INIT_POINTER(tfile->tun, NULL);
597 --tun->numqueues;
598 }
599 list_for_each_entry(tfile, &tun->disabled, next) {
600 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
601 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
602 RCU_INIT_POINTER(tfile->tun, NULL);
603 }
604 BUG_ON(tun->numqueues != 0);
605
606 synchronize_net();
607 for (i = 0; i < n; i++) {
608 tfile = rtnl_dereference(tun->tfiles[i]);
609 /* Drop read queue */
610 tun_queue_purge(tfile);
611 sock_put(&tfile->sk);
612 }
613 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
614 tun_enable_queue(tfile);
615 tun_queue_purge(tfile);
616 sock_put(&tfile->sk);
617 }
618 BUG_ON(tun->numdisabled != 0);
619
620 if (tun->flags & IFF_PERSIST)
621 module_put(THIS_MODULE);
622 }
623
624 static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter)
625 {
626 struct tun_file *tfile = file->private_data;
627 struct net_device *dev = tun->dev;
628 int err;
629
630 err = security_tun_dev_attach(tfile->socket.sk, tun->security);
631 if (err < 0)
632 goto out;
633
634 err = -EINVAL;
635 if (rtnl_dereference(tfile->tun) && !tfile->detached)
636 goto out;
637
638 err = -EBUSY;
639 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
640 goto out;
641
642 err = -E2BIG;
643 if (!tfile->detached &&
644 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
645 goto out;
646
647 err = 0;
648
649 /* Re-attach the filter to persist device */
650 if (!skip_filter && (tun->filter_attached == true)) {
651 lock_sock(tfile->socket.sk);
652 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
653 release_sock(tfile->socket.sk);
654 if (!err)
655 goto out;
656 }
657
658 if (!tfile->detached &&
659 skb_array_init(&tfile->tx_array, dev->tx_queue_len, GFP_KERNEL)) {
660 err = -ENOMEM;
661 goto out;
662 }
663
664 tfile->queue_index = tun->numqueues;
665 tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
666 rcu_assign_pointer(tfile->tun, tun);
667 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
668 tun->numqueues++;
669
670 if (tfile->detached)
671 tun_enable_queue(tfile);
672 else
673 sock_hold(&tfile->sk);
674
675 tun_set_real_num_queues(tun);
676
677 /* device is allowed to go away first, so no need to hold extra
678 * refcnt.
679 */
680
681 out:
682 return err;
683 }
684
685 static struct tun_struct *__tun_get(struct tun_file *tfile)
686 {
687 struct tun_struct *tun;
688
689 rcu_read_lock();
690 tun = rcu_dereference(tfile->tun);
691 if (tun)
692 dev_hold(tun->dev);
693 rcu_read_unlock();
694
695 return tun;
696 }
697
698 static struct tun_struct *tun_get(struct file *file)
699 {
700 return __tun_get(file->private_data);
701 }
702
703 static void tun_put(struct tun_struct *tun)
704 {
705 dev_put(tun->dev);
706 }
707
708 /* TAP filtering */
709 static void addr_hash_set(u32 *mask, const u8 *addr)
710 {
711 int n = ether_crc(ETH_ALEN, addr) >> 26;
712 mask[n >> 5] |= (1 << (n & 31));
713 }
714
715 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
716 {
717 int n = ether_crc(ETH_ALEN, addr) >> 26;
718 return mask[n >> 5] & (1 << (n & 31));
719 }
720
721 static int update_filter(struct tap_filter *filter, void __user *arg)
722 {
723 struct { u8 u[ETH_ALEN]; } *addr;
724 struct tun_filter uf;
725 int err, alen, n, nexact;
726
727 if (copy_from_user(&uf, arg, sizeof(uf)))
728 return -EFAULT;
729
730 if (!uf.count) {
731 /* Disabled */
732 filter->count = 0;
733 return 0;
734 }
735
736 alen = ETH_ALEN * uf.count;
737 addr = memdup_user(arg + sizeof(uf), alen);
738 if (IS_ERR(addr))
739 return PTR_ERR(addr);
740
741 /* The filter is updated without holding any locks. Which is
742 * perfectly safe. We disable it first and in the worst
743 * case we'll accept a few undesired packets. */
744 filter->count = 0;
745 wmb();
746
747 /* Use first set of addresses as an exact filter */
748 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
749 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
750
751 nexact = n;
752
753 /* Remaining multicast addresses are hashed,
754 * unicast will leave the filter disabled. */
755 memset(filter->mask, 0, sizeof(filter->mask));
756 for (; n < uf.count; n++) {
757 if (!is_multicast_ether_addr(addr[n].u)) {
758 err = 0; /* no filter */
759 goto free_addr;
760 }
761 addr_hash_set(filter->mask, addr[n].u);
762 }
763
764 /* For ALLMULTI just set the mask to all ones.
765 * This overrides the mask populated above. */
766 if ((uf.flags & TUN_FLT_ALLMULTI))
767 memset(filter->mask, ~0, sizeof(filter->mask));
768
769 /* Now enable the filter */
770 wmb();
771 filter->count = nexact;
772
773 /* Return the number of exact filters */
774 err = nexact;
775 free_addr:
776 kfree(addr);
777 return err;
778 }
779
780 /* Returns: 0 - drop, !=0 - accept */
781 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
782 {
783 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
784 * at this point. */
785 struct ethhdr *eh = (struct ethhdr *) skb->data;
786 int i;
787
788 /* Exact match */
789 for (i = 0; i < filter->count; i++)
790 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
791 return 1;
792
793 /* Inexact match (multicast only) */
794 if (is_multicast_ether_addr(eh->h_dest))
795 return addr_hash_test(filter->mask, eh->h_dest);
796
797 return 0;
798 }
799
800 /*
801 * Checks whether the packet is accepted or not.
802 * Returns: 0 - drop, !=0 - accept
803 */
804 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
805 {
806 if (!filter->count)
807 return 1;
808
809 return run_filter(filter, skb);
810 }
811
812 /* Network device part of the driver */
813
814 static const struct ethtool_ops tun_ethtool_ops;
815
816 /* Net device detach from fd. */
817 static void tun_net_uninit(struct net_device *dev)
818 {
819 tun_detach_all(dev);
820 }
821
822 /* Net device open. */
823 static int tun_net_open(struct net_device *dev)
824 {
825 struct tun_struct *tun = netdev_priv(dev);
826 int i;
827
828 netif_tx_start_all_queues(dev);
829
830 for (i = 0; i < tun->numqueues; i++) {
831 struct tun_file *tfile;
832
833 tfile = rtnl_dereference(tun->tfiles[i]);
834 tfile->socket.sk->sk_write_space(tfile->socket.sk);
835 }
836
837 return 0;
838 }
839
840 /* Net device close. */
841 static int tun_net_close(struct net_device *dev)
842 {
843 netif_tx_stop_all_queues(dev);
844 return 0;
845 }
846
847 /* Net device start xmit */
848 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
849 {
850 struct tun_struct *tun = netdev_priv(dev);
851 int txq = skb->queue_mapping;
852 struct tun_file *tfile;
853 u32 numqueues = 0;
854
855 rcu_read_lock();
856 tfile = rcu_dereference(tun->tfiles[txq]);
857 numqueues = ACCESS_ONCE(tun->numqueues);
858
859 /* Drop packet if interface is not attached */
860 if (txq >= numqueues)
861 goto drop;
862
863 #ifdef CONFIG_RPS
864 if (numqueues == 1 && static_key_false(&rps_needed)) {
865 /* Select queue was not called for the skbuff, so we extract the
866 * RPS hash and save it into the flow_table here.
867 */
868 __u32 rxhash;
869
870 rxhash = __skb_get_hash_symmetric(skb);
871 if (rxhash) {
872 struct tun_flow_entry *e;
873 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)],
874 rxhash);
875 if (e)
876 tun_flow_save_rps_rxhash(e, rxhash);
877 }
878 }
879 #endif
880
881 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
882
883 BUG_ON(!tfile);
884
885 /* Drop if the filter does not like it.
886 * This is a noop if the filter is disabled.
887 * Filter can be enabled only for the TAP devices. */
888 if (!check_filter(&tun->txflt, skb))
889 goto drop;
890
891 if (tfile->socket.sk->sk_filter &&
892 sk_filter(tfile->socket.sk, skb))
893 goto drop;
894
895 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
896 goto drop;
897
898 skb_tx_timestamp(skb);
899
900 /* Orphan the skb - required as we might hang on to it
901 * for indefinite time.
902 */
903 skb_orphan(skb);
904
905 nf_reset(skb);
906
907 if (skb_array_produce(&tfile->tx_array, skb))
908 goto drop;
909
910 /* Notify and wake up reader process */
911 if (tfile->flags & TUN_FASYNC)
912 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
913 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
914
915 rcu_read_unlock();
916 return NETDEV_TX_OK;
917
918 drop:
919 this_cpu_inc(tun->pcpu_stats->tx_dropped);
920 skb_tx_error(skb);
921 kfree_skb(skb);
922 rcu_read_unlock();
923 return NET_XMIT_DROP;
924 }
925
926 static void tun_net_mclist(struct net_device *dev)
927 {
928 /*
929 * This callback is supposed to deal with mc filter in
930 * _rx_ path and has nothing to do with the _tx_ path.
931 * In rx path we always accept everything userspace gives us.
932 */
933 }
934
935 static netdev_features_t tun_net_fix_features(struct net_device *dev,
936 netdev_features_t features)
937 {
938 struct tun_struct *tun = netdev_priv(dev);
939
940 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
941 }
942 #ifdef CONFIG_NET_POLL_CONTROLLER
943 static void tun_poll_controller(struct net_device *dev)
944 {
945 /*
946 * Tun only receives frames when:
947 * 1) the char device endpoint gets data from user space
948 * 2) the tun socket gets a sendmsg call from user space
949 * Since both of those are synchronous operations, we are guaranteed
950 * never to have pending data when we poll for it
951 * so there is nothing to do here but return.
952 * We need this though so netpoll recognizes us as an interface that
953 * supports polling, which enables bridge devices in virt setups to
954 * still use netconsole
955 */
956 return;
957 }
958 #endif
959
960 static void tun_set_headroom(struct net_device *dev, int new_hr)
961 {
962 struct tun_struct *tun = netdev_priv(dev);
963
964 if (new_hr < NET_SKB_PAD)
965 new_hr = NET_SKB_PAD;
966
967 tun->align = new_hr;
968 }
969
970 static void
971 tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
972 {
973 u32 rx_dropped = 0, tx_dropped = 0, rx_frame_errors = 0;
974 struct tun_struct *tun = netdev_priv(dev);
975 struct tun_pcpu_stats *p;
976 int i;
977
978 for_each_possible_cpu(i) {
979 u64 rxpackets, rxbytes, txpackets, txbytes;
980 unsigned int start;
981
982 p = per_cpu_ptr(tun->pcpu_stats, i);
983 do {
984 start = u64_stats_fetch_begin(&p->syncp);
985 rxpackets = p->rx_packets;
986 rxbytes = p->rx_bytes;
987 txpackets = p->tx_packets;
988 txbytes = p->tx_bytes;
989 } while (u64_stats_fetch_retry(&p->syncp, start));
990
991 stats->rx_packets += rxpackets;
992 stats->rx_bytes += rxbytes;
993 stats->tx_packets += txpackets;
994 stats->tx_bytes += txbytes;
995
996 /* u32 counters */
997 rx_dropped += p->rx_dropped;
998 rx_frame_errors += p->rx_frame_errors;
999 tx_dropped += p->tx_dropped;
1000 }
1001 stats->rx_dropped = rx_dropped;
1002 stats->rx_frame_errors = rx_frame_errors;
1003 stats->tx_dropped = tx_dropped;
1004 }
1005
1006 static const struct net_device_ops tun_netdev_ops = {
1007 .ndo_uninit = tun_net_uninit,
1008 .ndo_open = tun_net_open,
1009 .ndo_stop = tun_net_close,
1010 .ndo_start_xmit = tun_net_xmit,
1011 .ndo_fix_features = tun_net_fix_features,
1012 .ndo_select_queue = tun_select_queue,
1013 #ifdef CONFIG_NET_POLL_CONTROLLER
1014 .ndo_poll_controller = tun_poll_controller,
1015 #endif
1016 .ndo_set_rx_headroom = tun_set_headroom,
1017 .ndo_get_stats64 = tun_net_get_stats64,
1018 };
1019
1020 static const struct net_device_ops tap_netdev_ops = {
1021 .ndo_uninit = tun_net_uninit,
1022 .ndo_open = tun_net_open,
1023 .ndo_stop = tun_net_close,
1024 .ndo_start_xmit = tun_net_xmit,
1025 .ndo_fix_features = tun_net_fix_features,
1026 .ndo_set_rx_mode = tun_net_mclist,
1027 .ndo_set_mac_address = eth_mac_addr,
1028 .ndo_validate_addr = eth_validate_addr,
1029 .ndo_select_queue = tun_select_queue,
1030 #ifdef CONFIG_NET_POLL_CONTROLLER
1031 .ndo_poll_controller = tun_poll_controller,
1032 #endif
1033 .ndo_features_check = passthru_features_check,
1034 .ndo_set_rx_headroom = tun_set_headroom,
1035 .ndo_get_stats64 = tun_net_get_stats64,
1036 };
1037
1038 static void tun_flow_init(struct tun_struct *tun)
1039 {
1040 int i;
1041
1042 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1043 INIT_HLIST_HEAD(&tun->flows[i]);
1044
1045 tun->ageing_time = TUN_FLOW_EXPIRE;
1046 setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun);
1047 mod_timer(&tun->flow_gc_timer,
1048 round_jiffies_up(jiffies + tun->ageing_time));
1049 }
1050
1051 static void tun_flow_uninit(struct tun_struct *tun)
1052 {
1053 del_timer_sync(&tun->flow_gc_timer);
1054 tun_flow_flush(tun);
1055 }
1056
1057 #define MIN_MTU 68
1058 #define MAX_MTU 65535
1059
1060 /* Initialize net device. */
1061 static void tun_net_init(struct net_device *dev)
1062 {
1063 struct tun_struct *tun = netdev_priv(dev);
1064
1065 switch (tun->flags & TUN_TYPE_MASK) {
1066 case IFF_TUN:
1067 dev->netdev_ops = &tun_netdev_ops;
1068
1069 /* Point-to-Point TUN Device */
1070 dev->hard_header_len = 0;
1071 dev->addr_len = 0;
1072 dev->mtu = 1500;
1073
1074 /* Zero header length */
1075 dev->type = ARPHRD_NONE;
1076 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1077 break;
1078
1079 case IFF_TAP:
1080 dev->netdev_ops = &tap_netdev_ops;
1081 /* Ethernet TAP Device */
1082 ether_setup(dev);
1083 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1084 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1085
1086 eth_hw_addr_random(dev);
1087
1088 break;
1089 }
1090
1091 dev->min_mtu = MIN_MTU;
1092 dev->max_mtu = MAX_MTU - dev->hard_header_len;
1093 }
1094
1095 /* Character device part */
1096
1097 /* Poll */
1098 static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
1099 {
1100 struct tun_file *tfile = file->private_data;
1101 struct tun_struct *tun = __tun_get(tfile);
1102 struct sock *sk;
1103 unsigned int mask = 0;
1104
1105 if (!tun)
1106 return POLLERR;
1107
1108 sk = tfile->socket.sk;
1109
1110 tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
1111
1112 poll_wait(file, sk_sleep(sk), wait);
1113
1114 if (!skb_array_empty(&tfile->tx_array))
1115 mask |= POLLIN | POLLRDNORM;
1116
1117 if (tun->dev->flags & IFF_UP &&
1118 (sock_writeable(sk) ||
1119 (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1120 sock_writeable(sk))))
1121 mask |= POLLOUT | POLLWRNORM;
1122
1123 if (tun->dev->reg_state != NETREG_REGISTERED)
1124 mask = POLLERR;
1125
1126 tun_put(tun);
1127 return mask;
1128 }
1129
1130 /* prepad is the amount to reserve at front. len is length after that.
1131 * linear is a hint as to how much to copy (usually headers). */
1132 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1133 size_t prepad, size_t len,
1134 size_t linear, int noblock)
1135 {
1136 struct sock *sk = tfile->socket.sk;
1137 struct sk_buff *skb;
1138 int err;
1139
1140 /* Under a page? Don't bother with paged skb. */
1141 if (prepad + len < PAGE_SIZE || !linear)
1142 linear = len;
1143
1144 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1145 &err, 0);
1146 if (!skb)
1147 return ERR_PTR(err);
1148
1149 skb_reserve(skb, prepad);
1150 skb_put(skb, linear);
1151 skb->data_len = len - linear;
1152 skb->len += len - linear;
1153
1154 return skb;
1155 }
1156
1157 static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile,
1158 struct sk_buff *skb, int more)
1159 {
1160 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1161 struct sk_buff_head process_queue;
1162 u32 rx_batched = tun->rx_batched;
1163 bool rcv = false;
1164
1165 if (!rx_batched || (!more && skb_queue_empty(queue))) {
1166 local_bh_disable();
1167 netif_receive_skb(skb);
1168 local_bh_enable();
1169 return;
1170 }
1171
1172 spin_lock(&queue->lock);
1173 if (!more || skb_queue_len(queue) == rx_batched) {
1174 __skb_queue_head_init(&process_queue);
1175 skb_queue_splice_tail_init(queue, &process_queue);
1176 rcv = true;
1177 } else {
1178 __skb_queue_tail(queue, skb);
1179 }
1180 spin_unlock(&queue->lock);
1181
1182 if (rcv) {
1183 struct sk_buff *nskb;
1184
1185 local_bh_disable();
1186 while ((nskb = __skb_dequeue(&process_queue)))
1187 netif_receive_skb(nskb);
1188 netif_receive_skb(skb);
1189 local_bh_enable();
1190 }
1191 }
1192
1193 /* Get packet from user space buffer */
1194 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1195 void *msg_control, struct iov_iter *from,
1196 int noblock, bool more)
1197 {
1198 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1199 struct sk_buff *skb;
1200 size_t total_len = iov_iter_count(from);
1201 size_t len = total_len, align = tun->align, linear;
1202 struct virtio_net_hdr gso = { 0 };
1203 struct tun_pcpu_stats *stats;
1204 int good_linear;
1205 int copylen;
1206 bool zerocopy = false;
1207 int err;
1208 u32 rxhash;
1209
1210 if (!(tun->dev->flags & IFF_UP))
1211 return -EIO;
1212
1213 if (!(tun->flags & IFF_NO_PI)) {
1214 if (len < sizeof(pi))
1215 return -EINVAL;
1216 len -= sizeof(pi);
1217
1218 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1219 return -EFAULT;
1220 }
1221
1222 if (tun->flags & IFF_VNET_HDR) {
1223 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1224
1225 if (len < vnet_hdr_sz)
1226 return -EINVAL;
1227 len -= vnet_hdr_sz;
1228
1229 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1230 return -EFAULT;
1231
1232 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1233 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1234 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1235
1236 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1237 return -EINVAL;
1238 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1239 }
1240
1241 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1242 align += NET_IP_ALIGN;
1243 if (unlikely(len < ETH_HLEN ||
1244 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1245 return -EINVAL;
1246 }
1247
1248 good_linear = SKB_MAX_HEAD(align);
1249
1250 if (msg_control) {
1251 struct iov_iter i = *from;
1252
1253 /* There are 256 bytes to be copied in skb, so there is
1254 * enough room for skb expand head in case it is used.
1255 * The rest of the buffer is mapped from userspace.
1256 */
1257 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1258 if (copylen > good_linear)
1259 copylen = good_linear;
1260 linear = copylen;
1261 iov_iter_advance(&i, copylen);
1262 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1263 zerocopy = true;
1264 }
1265
1266 if (!zerocopy) {
1267 copylen = len;
1268 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1269 linear = good_linear;
1270 else
1271 linear = tun16_to_cpu(tun, gso.hdr_len);
1272 }
1273
1274 skb = tun_alloc_skb(tfile, align, copylen, linear, noblock);
1275 if (IS_ERR(skb)) {
1276 if (PTR_ERR(skb) != -EAGAIN)
1277 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1278 return PTR_ERR(skb);
1279 }
1280
1281 if (zerocopy)
1282 err = zerocopy_sg_from_iter(skb, from);
1283 else
1284 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1285
1286 if (err) {
1287 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1288 kfree_skb(skb);
1289 return -EFAULT;
1290 }
1291
1292 if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1293 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
1294 kfree_skb(skb);
1295 return -EINVAL;
1296 }
1297
1298 switch (tun->flags & TUN_TYPE_MASK) {
1299 case IFF_TUN:
1300 if (tun->flags & IFF_NO_PI) {
1301 switch (skb->data[0] & 0xf0) {
1302 case 0x40:
1303 pi.proto = htons(ETH_P_IP);
1304 break;
1305 case 0x60:
1306 pi.proto = htons(ETH_P_IPV6);
1307 break;
1308 default:
1309 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1310 kfree_skb(skb);
1311 return -EINVAL;
1312 }
1313 }
1314
1315 skb_reset_mac_header(skb);
1316 skb->protocol = pi.proto;
1317 skb->dev = tun->dev;
1318 break;
1319 case IFF_TAP:
1320 skb->protocol = eth_type_trans(skb, tun->dev);
1321 break;
1322 }
1323
1324 /* copy skb_ubuf_info for callback when skb has no error */
1325 if (zerocopy) {
1326 skb_shinfo(skb)->destructor_arg = msg_control;
1327 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1328 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1329 } else if (msg_control) {
1330 struct ubuf_info *uarg = msg_control;
1331 uarg->callback(uarg, false);
1332 }
1333
1334 skb_reset_network_header(skb);
1335 skb_probe_transport_header(skb, 0);
1336
1337 rxhash = __skb_get_hash_symmetric(skb);
1338 #ifndef CONFIG_4KSTACKS
1339 tun_rx_batched(tun, tfile, skb, more);
1340 #else
1341 netif_rx_ni(skb);
1342 #endif
1343
1344 stats = get_cpu_ptr(tun->pcpu_stats);
1345 u64_stats_update_begin(&stats->syncp);
1346 stats->rx_packets++;
1347 stats->rx_bytes += len;
1348 u64_stats_update_end(&stats->syncp);
1349 put_cpu_ptr(stats);
1350
1351 tun_flow_update(tun, rxhash, tfile);
1352 return total_len;
1353 }
1354
1355 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
1356 {
1357 struct file *file = iocb->ki_filp;
1358 struct tun_struct *tun = tun_get(file);
1359 struct tun_file *tfile = file->private_data;
1360 ssize_t result;
1361
1362 if (!tun)
1363 return -EBADFD;
1364
1365 result = tun_get_user(tun, tfile, NULL, from,
1366 file->f_flags & O_NONBLOCK, false);
1367
1368 tun_put(tun);
1369 return result;
1370 }
1371
1372 /* Put packet to the user space buffer */
1373 static ssize_t tun_put_user(struct tun_struct *tun,
1374 struct tun_file *tfile,
1375 struct sk_buff *skb,
1376 struct iov_iter *iter)
1377 {
1378 struct tun_pi pi = { 0, skb->protocol };
1379 struct tun_pcpu_stats *stats;
1380 ssize_t total;
1381 int vlan_offset = 0;
1382 int vlan_hlen = 0;
1383 int vnet_hdr_sz = 0;
1384
1385 if (skb_vlan_tag_present(skb))
1386 vlan_hlen = VLAN_HLEN;
1387
1388 if (tun->flags & IFF_VNET_HDR)
1389 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1390
1391 total = skb->len + vlan_hlen + vnet_hdr_sz;
1392
1393 if (!(tun->flags & IFF_NO_PI)) {
1394 if (iov_iter_count(iter) < sizeof(pi))
1395 return -EINVAL;
1396
1397 total += sizeof(pi);
1398 if (iov_iter_count(iter) < total) {
1399 /* Packet will be striped */
1400 pi.flags |= TUN_PKT_STRIP;
1401 }
1402
1403 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
1404 return -EFAULT;
1405 }
1406
1407 if (vnet_hdr_sz) {
1408 struct virtio_net_hdr gso;
1409
1410 if (iov_iter_count(iter) < vnet_hdr_sz)
1411 return -EINVAL;
1412
1413 if (virtio_net_hdr_from_skb(skb, &gso,
1414 tun_is_little_endian(tun), true)) {
1415 struct skb_shared_info *sinfo = skb_shinfo(skb);
1416 pr_err("unexpected GSO type: "
1417 "0x%x, gso_size %d, hdr_len %d\n",
1418 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
1419 tun16_to_cpu(tun, gso.hdr_len));
1420 print_hex_dump(KERN_ERR, "tun: ",
1421 DUMP_PREFIX_NONE,
1422 16, 1, skb->head,
1423 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
1424 WARN_ON_ONCE(1);
1425 return -EINVAL;
1426 }
1427
1428 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
1429 return -EFAULT;
1430
1431 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
1432 }
1433
1434 if (vlan_hlen) {
1435 int ret;
1436 struct {
1437 __be16 h_vlan_proto;
1438 __be16 h_vlan_TCI;
1439 } veth;
1440
1441 veth.h_vlan_proto = skb->vlan_proto;
1442 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
1443
1444 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
1445
1446 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
1447 if (ret || !iov_iter_count(iter))
1448 goto done;
1449
1450 ret = copy_to_iter(&veth, sizeof(veth), iter);
1451 if (ret != sizeof(veth) || !iov_iter_count(iter))
1452 goto done;
1453 }
1454
1455 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
1456
1457 done:
1458 /* caller is in process context, */
1459 stats = get_cpu_ptr(tun->pcpu_stats);
1460 u64_stats_update_begin(&stats->syncp);
1461 stats->tx_packets++;
1462 stats->tx_bytes += skb->len + vlan_hlen;
1463 u64_stats_update_end(&stats->syncp);
1464 put_cpu_ptr(tun->pcpu_stats);
1465
1466 return total;
1467 }
1468
1469 static struct sk_buff *tun_ring_recv(struct tun_file *tfile, int noblock,
1470 int *err)
1471 {
1472 DECLARE_WAITQUEUE(wait, current);
1473 struct sk_buff *skb = NULL;
1474 int error = 0;
1475
1476 skb = skb_array_consume(&tfile->tx_array);
1477 if (skb)
1478 goto out;
1479 if (noblock) {
1480 error = -EAGAIN;
1481 goto out;
1482 }
1483
1484 add_wait_queue(&tfile->wq.wait, &wait);
1485 current->state = TASK_INTERRUPTIBLE;
1486
1487 while (1) {
1488 skb = skb_array_consume(&tfile->tx_array);
1489 if (skb)
1490 break;
1491 if (signal_pending(current)) {
1492 error = -ERESTARTSYS;
1493 break;
1494 }
1495 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
1496 error = -EFAULT;
1497 break;
1498 }
1499
1500 schedule();
1501 }
1502
1503 current->state = TASK_RUNNING;
1504 remove_wait_queue(&tfile->wq.wait, &wait);
1505
1506 out:
1507 *err = error;
1508 return skb;
1509 }
1510
1511 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
1512 struct iov_iter *to,
1513 int noblock, struct sk_buff *skb)
1514 {
1515 ssize_t ret;
1516 int err;
1517
1518 tun_debug(KERN_INFO, tun, "tun_do_read\n");
1519
1520 if (!iov_iter_count(to))
1521 return 0;
1522
1523 if (!skb) {
1524 /* Read frames from ring */
1525 skb = tun_ring_recv(tfile, noblock, &err);
1526 if (!skb)
1527 return err;
1528 }
1529
1530 ret = tun_put_user(tun, tfile, skb, to);
1531 if (unlikely(ret < 0))
1532 kfree_skb(skb);
1533 else
1534 consume_skb(skb);
1535
1536 return ret;
1537 }
1538
1539 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
1540 {
1541 struct file *file = iocb->ki_filp;
1542 struct tun_file *tfile = file->private_data;
1543 struct tun_struct *tun = __tun_get(tfile);
1544 ssize_t len = iov_iter_count(to), ret;
1545
1546 if (!tun)
1547 return -EBADFD;
1548 ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK, NULL);
1549 ret = min_t(ssize_t, ret, len);
1550 if (ret > 0)
1551 iocb->ki_pos = ret;
1552 tun_put(tun);
1553 return ret;
1554 }
1555
1556 static void tun_free_netdev(struct net_device *dev)
1557 {
1558 struct tun_struct *tun = netdev_priv(dev);
1559
1560 BUG_ON(!(list_empty(&tun->disabled)));
1561 free_percpu(tun->pcpu_stats);
1562 tun_flow_uninit(tun);
1563 security_tun_dev_free_security(tun->security);
1564 }
1565
1566 static void tun_setup(struct net_device *dev)
1567 {
1568 struct tun_struct *tun = netdev_priv(dev);
1569
1570 tun->owner = INVALID_UID;
1571 tun->group = INVALID_GID;
1572
1573 dev->ethtool_ops = &tun_ethtool_ops;
1574 dev->needs_free_netdev = true;
1575 dev->priv_destructor = tun_free_netdev;
1576 /* We prefer our own queue length */
1577 dev->tx_queue_len = TUN_READQ_SIZE;
1578 }
1579
1580 /* Trivial set of netlink ops to allow deleting tun or tap
1581 * device with netlink.
1582 */
1583 static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
1584 struct netlink_ext_ack *extack)
1585 {
1586 return -EINVAL;
1587 }
1588
1589 static struct rtnl_link_ops tun_link_ops __read_mostly = {
1590 .kind = DRV_NAME,
1591 .priv_size = sizeof(struct tun_struct),
1592 .setup = tun_setup,
1593 .validate = tun_validate,
1594 };
1595
1596 static void tun_sock_write_space(struct sock *sk)
1597 {
1598 struct tun_file *tfile;
1599 wait_queue_head_t *wqueue;
1600
1601 if (!sock_writeable(sk))
1602 return;
1603
1604 if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
1605 return;
1606
1607 wqueue = sk_sleep(sk);
1608 if (wqueue && waitqueue_active(wqueue))
1609 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1610 POLLWRNORM | POLLWRBAND);
1611
1612 tfile = container_of(sk, struct tun_file, sk);
1613 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
1614 }
1615
1616 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
1617 {
1618 int ret;
1619 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1620 struct tun_struct *tun = __tun_get(tfile);
1621
1622 if (!tun)
1623 return -EBADFD;
1624
1625 ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter,
1626 m->msg_flags & MSG_DONTWAIT,
1627 m->msg_flags & MSG_MORE);
1628 tun_put(tun);
1629 return ret;
1630 }
1631
1632 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
1633 int flags)
1634 {
1635 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1636 struct tun_struct *tun = __tun_get(tfile);
1637 int ret;
1638
1639 if (!tun)
1640 return -EBADFD;
1641
1642 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
1643 ret = -EINVAL;
1644 goto out;
1645 }
1646 if (flags & MSG_ERRQUEUE) {
1647 ret = sock_recv_errqueue(sock->sk, m, total_len,
1648 SOL_PACKET, TUN_TX_TIMESTAMP);
1649 goto out;
1650 }
1651 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT,
1652 m->msg_control);
1653 if (ret > (ssize_t)total_len) {
1654 m->msg_flags |= MSG_TRUNC;
1655 ret = flags & MSG_TRUNC ? ret : total_len;
1656 }
1657 out:
1658 tun_put(tun);
1659 return ret;
1660 }
1661
1662 static int tun_peek_len(struct socket *sock)
1663 {
1664 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1665 struct tun_struct *tun;
1666 int ret = 0;
1667
1668 tun = __tun_get(tfile);
1669 if (!tun)
1670 return 0;
1671
1672 ret = skb_array_peek_len(&tfile->tx_array);
1673 tun_put(tun);
1674
1675 return ret;
1676 }
1677
1678 /* Ops structure to mimic raw sockets with tun */
1679 static const struct proto_ops tun_socket_ops = {
1680 .peek_len = tun_peek_len,
1681 .sendmsg = tun_sendmsg,
1682 .recvmsg = tun_recvmsg,
1683 };
1684
1685 static struct proto tun_proto = {
1686 .name = "tun",
1687 .owner = THIS_MODULE,
1688 .obj_size = sizeof(struct tun_file),
1689 };
1690
1691 static int tun_flags(struct tun_struct *tun)
1692 {
1693 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
1694 }
1695
1696 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1697 char *buf)
1698 {
1699 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1700 return sprintf(buf, "0x%x\n", tun_flags(tun));
1701 }
1702
1703 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1704 char *buf)
1705 {
1706 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1707 return uid_valid(tun->owner)?
1708 sprintf(buf, "%u\n",
1709 from_kuid_munged(current_user_ns(), tun->owner)):
1710 sprintf(buf, "-1\n");
1711 }
1712
1713 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1714 char *buf)
1715 {
1716 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1717 return gid_valid(tun->group) ?
1718 sprintf(buf, "%u\n",
1719 from_kgid_munged(current_user_ns(), tun->group)):
1720 sprintf(buf, "-1\n");
1721 }
1722
1723 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1724 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1725 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1726
1727 static struct attribute *tun_dev_attrs[] = {
1728 &dev_attr_tun_flags.attr,
1729 &dev_attr_owner.attr,
1730 &dev_attr_group.attr,
1731 NULL
1732 };
1733
1734 static const struct attribute_group tun_attr_group = {
1735 .attrs = tun_dev_attrs
1736 };
1737
1738 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1739 {
1740 struct tun_struct *tun;
1741 struct tun_file *tfile = file->private_data;
1742 struct net_device *dev;
1743 int err;
1744
1745 if (tfile->detached)
1746 return -EINVAL;
1747
1748 dev = __dev_get_by_name(net, ifr->ifr_name);
1749 if (dev) {
1750 if (ifr->ifr_flags & IFF_TUN_EXCL)
1751 return -EBUSY;
1752 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1753 tun = netdev_priv(dev);
1754 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1755 tun = netdev_priv(dev);
1756 else
1757 return -EINVAL;
1758
1759 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
1760 !!(tun->flags & IFF_MULTI_QUEUE))
1761 return -EINVAL;
1762
1763 if (tun_not_capable(tun))
1764 return -EPERM;
1765 err = security_tun_dev_open(tun->security);
1766 if (err < 0)
1767 return err;
1768
1769 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER);
1770 if (err < 0)
1771 return err;
1772
1773 if (tun->flags & IFF_MULTI_QUEUE &&
1774 (tun->numqueues + tun->numdisabled > 1)) {
1775 /* One or more queue has already been attached, no need
1776 * to initialize the device again.
1777 */
1778 return 0;
1779 }
1780 }
1781 else {
1782 char *name;
1783 unsigned long flags = 0;
1784 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
1785 MAX_TAP_QUEUES : 1;
1786
1787 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1788 return -EPERM;
1789 err = security_tun_dev_create();
1790 if (err < 0)
1791 return err;
1792
1793 /* Set dev type */
1794 if (ifr->ifr_flags & IFF_TUN) {
1795 /* TUN device */
1796 flags |= IFF_TUN;
1797 name = "tun%d";
1798 } else if (ifr->ifr_flags & IFF_TAP) {
1799 /* TAP device */
1800 flags |= IFF_TAP;
1801 name = "tap%d";
1802 } else
1803 return -EINVAL;
1804
1805 if (*ifr->ifr_name)
1806 name = ifr->ifr_name;
1807
1808 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
1809 NET_NAME_UNKNOWN, tun_setup, queues,
1810 queues);
1811
1812 if (!dev)
1813 return -ENOMEM;
1814
1815 dev_net_set(dev, net);
1816 dev->rtnl_link_ops = &tun_link_ops;
1817 dev->ifindex = tfile->ifindex;
1818 dev->sysfs_groups[0] = &tun_attr_group;
1819
1820 tun = netdev_priv(dev);
1821 tun->dev = dev;
1822 tun->flags = flags;
1823 tun->txflt.count = 0;
1824 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1825
1826 tun->align = NET_SKB_PAD;
1827 tun->filter_attached = false;
1828 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
1829 tun->rx_batched = 0;
1830
1831 tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats);
1832 if (!tun->pcpu_stats) {
1833 err = -ENOMEM;
1834 goto err_free_dev;
1835 }
1836
1837 spin_lock_init(&tun->lock);
1838
1839 err = security_tun_dev_alloc_security(&tun->security);
1840 if (err < 0)
1841 goto err_free_stat;
1842
1843 tun_net_init(dev);
1844 tun_flow_init(tun);
1845
1846 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1847 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
1848 NETIF_F_HW_VLAN_STAG_TX;
1849 dev->features = dev->hw_features | NETIF_F_LLTX;
1850 dev->vlan_features = dev->features &
1851 ~(NETIF_F_HW_VLAN_CTAG_TX |
1852 NETIF_F_HW_VLAN_STAG_TX);
1853
1854 INIT_LIST_HEAD(&tun->disabled);
1855 err = tun_attach(tun, file, false);
1856 if (err < 0)
1857 goto err_free_flow;
1858
1859 err = register_netdevice(tun->dev);
1860 if (err < 0)
1861 goto err_detach;
1862 }
1863
1864 netif_carrier_on(tun->dev);
1865
1866 tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1867
1868 tun->flags = (tun->flags & ~TUN_FEATURES) |
1869 (ifr->ifr_flags & TUN_FEATURES);
1870
1871 /* Make sure persistent devices do not get stuck in
1872 * xoff state.
1873 */
1874 if (netif_running(tun->dev))
1875 netif_tx_wake_all_queues(tun->dev);
1876
1877 strcpy(ifr->ifr_name, tun->dev->name);
1878 return 0;
1879
1880 err_detach:
1881 tun_detach_all(dev);
1882 err_free_flow:
1883 tun_flow_uninit(tun);
1884 security_tun_dev_free_security(tun->security);
1885 err_free_stat:
1886 free_percpu(tun->pcpu_stats);
1887 err_free_dev:
1888 free_netdev(dev);
1889 return err;
1890 }
1891
1892 static void tun_get_iff(struct net *net, struct tun_struct *tun,
1893 struct ifreq *ifr)
1894 {
1895 tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1896
1897 strcpy(ifr->ifr_name, tun->dev->name);
1898
1899 ifr->ifr_flags = tun_flags(tun);
1900
1901 }
1902
1903 /* This is like a cut-down ethtool ops, except done via tun fd so no
1904 * privs required. */
1905 static int set_offload(struct tun_struct *tun, unsigned long arg)
1906 {
1907 netdev_features_t features = 0;
1908
1909 if (arg & TUN_F_CSUM) {
1910 features |= NETIF_F_HW_CSUM;
1911 arg &= ~TUN_F_CSUM;
1912
1913 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1914 if (arg & TUN_F_TSO_ECN) {
1915 features |= NETIF_F_TSO_ECN;
1916 arg &= ~TUN_F_TSO_ECN;
1917 }
1918 if (arg & TUN_F_TSO4)
1919 features |= NETIF_F_TSO;
1920 if (arg & TUN_F_TSO6)
1921 features |= NETIF_F_TSO6;
1922 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1923 }
1924
1925 if (arg & TUN_F_UFO) {
1926 features |= NETIF_F_UFO;
1927 arg &= ~TUN_F_UFO;
1928 }
1929 }
1930
1931 /* This gives the user a way to test for new features in future by
1932 * trying to set them. */
1933 if (arg)
1934 return -EINVAL;
1935
1936 tun->set_features = features;
1937 tun->dev->wanted_features &= ~TUN_USER_FEATURES;
1938 tun->dev->wanted_features |= features;
1939 netdev_update_features(tun->dev);
1940
1941 return 0;
1942 }
1943
1944 static void tun_detach_filter(struct tun_struct *tun, int n)
1945 {
1946 int i;
1947 struct tun_file *tfile;
1948
1949 for (i = 0; i < n; i++) {
1950 tfile = rtnl_dereference(tun->tfiles[i]);
1951 lock_sock(tfile->socket.sk);
1952 sk_detach_filter(tfile->socket.sk);
1953 release_sock(tfile->socket.sk);
1954 }
1955
1956 tun->filter_attached = false;
1957 }
1958
1959 static int tun_attach_filter(struct tun_struct *tun)
1960 {
1961 int i, ret = 0;
1962 struct tun_file *tfile;
1963
1964 for (i = 0; i < tun->numqueues; i++) {
1965 tfile = rtnl_dereference(tun->tfiles[i]);
1966 lock_sock(tfile->socket.sk);
1967 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
1968 release_sock(tfile->socket.sk);
1969 if (ret) {
1970 tun_detach_filter(tun, i);
1971 return ret;
1972 }
1973 }
1974
1975 tun->filter_attached = true;
1976 return ret;
1977 }
1978
1979 static void tun_set_sndbuf(struct tun_struct *tun)
1980 {
1981 struct tun_file *tfile;
1982 int i;
1983
1984 for (i = 0; i < tun->numqueues; i++) {
1985 tfile = rtnl_dereference(tun->tfiles[i]);
1986 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
1987 }
1988 }
1989
1990 static int tun_set_queue(struct file *file, struct ifreq *ifr)
1991 {
1992 struct tun_file *tfile = file->private_data;
1993 struct tun_struct *tun;
1994 int ret = 0;
1995
1996 rtnl_lock();
1997
1998 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
1999 tun = tfile->detached;
2000 if (!tun) {
2001 ret = -EINVAL;
2002 goto unlock;
2003 }
2004 ret = security_tun_dev_attach_queue(tun->security);
2005 if (ret < 0)
2006 goto unlock;
2007 ret = tun_attach(tun, file, false);
2008 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
2009 tun = rtnl_dereference(tfile->tun);
2010 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
2011 ret = -EINVAL;
2012 else
2013 __tun_detach(tfile, false);
2014 } else
2015 ret = -EINVAL;
2016
2017 unlock:
2018 rtnl_unlock();
2019 return ret;
2020 }
2021
2022 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
2023 unsigned long arg, int ifreq_len)
2024 {
2025 struct tun_file *tfile = file->private_data;
2026 struct tun_struct *tun;
2027 void __user* argp = (void __user*)arg;
2028 struct ifreq ifr;
2029 kuid_t owner;
2030 kgid_t group;
2031 int sndbuf;
2032 int vnet_hdr_sz;
2033 unsigned int ifindex;
2034 int le;
2035 int ret;
2036
2037 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == SOCK_IOC_TYPE) {
2038 if (copy_from_user(&ifr, argp, ifreq_len))
2039 return -EFAULT;
2040 } else {
2041 memset(&ifr, 0, sizeof(ifr));
2042 }
2043 if (cmd == TUNGETFEATURES) {
2044 /* Currently this just means: "what IFF flags are valid?".
2045 * This is needed because we never checked for invalid flags on
2046 * TUNSETIFF.
2047 */
2048 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
2049 (unsigned int __user*)argp);
2050 } else if (cmd == TUNSETQUEUE)
2051 return tun_set_queue(file, &ifr);
2052
2053 ret = 0;
2054 rtnl_lock();
2055
2056 tun = __tun_get(tfile);
2057 if (cmd == TUNSETIFF) {
2058 ret = -EEXIST;
2059 if (tun)
2060 goto unlock;
2061
2062 ifr.ifr_name[IFNAMSIZ-1] = '\0';
2063
2064 ret = tun_set_iff(sock_net(&tfile->sk), file, &ifr);
2065
2066 if (ret)
2067 goto unlock;
2068
2069 if (copy_to_user(argp, &ifr, ifreq_len))
2070 ret = -EFAULT;
2071 goto unlock;
2072 }
2073 if (cmd == TUNSETIFINDEX) {
2074 ret = -EPERM;
2075 if (tun)
2076 goto unlock;
2077
2078 ret = -EFAULT;
2079 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
2080 goto unlock;
2081
2082 ret = 0;
2083 tfile->ifindex = ifindex;
2084 goto unlock;
2085 }
2086
2087 ret = -EBADFD;
2088 if (!tun)
2089 goto unlock;
2090
2091 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
2092
2093 ret = 0;
2094 switch (cmd) {
2095 case TUNGETIFF:
2096 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2097
2098 if (tfile->detached)
2099 ifr.ifr_flags |= IFF_DETACH_QUEUE;
2100 if (!tfile->socket.sk->sk_filter)
2101 ifr.ifr_flags |= IFF_NOFILTER;
2102
2103 if (copy_to_user(argp, &ifr, ifreq_len))
2104 ret = -EFAULT;
2105 break;
2106
2107 case TUNSETNOCSUM:
2108 /* Disable/Enable checksum */
2109
2110 /* [unimplemented] */
2111 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
2112 arg ? "disabled" : "enabled");
2113 break;
2114
2115 case TUNSETPERSIST:
2116 /* Disable/Enable persist mode. Keep an extra reference to the
2117 * module to prevent the module being unprobed.
2118 */
2119 if (arg && !(tun->flags & IFF_PERSIST)) {
2120 tun->flags |= IFF_PERSIST;
2121 __module_get(THIS_MODULE);
2122 }
2123 if (!arg && (tun->flags & IFF_PERSIST)) {
2124 tun->flags &= ~IFF_PERSIST;
2125 module_put(THIS_MODULE);
2126 }
2127
2128 tun_debug(KERN_INFO, tun, "persist %s\n",
2129 arg ? "enabled" : "disabled");
2130 break;
2131
2132 case TUNSETOWNER:
2133 /* Set owner of the device */
2134 owner = make_kuid(current_user_ns(), arg);
2135 if (!uid_valid(owner)) {
2136 ret = -EINVAL;
2137 break;
2138 }
2139 tun->owner = owner;
2140 tun_debug(KERN_INFO, tun, "owner set to %u\n",
2141 from_kuid(&init_user_ns, tun->owner));
2142 break;
2143
2144 case TUNSETGROUP:
2145 /* Set group of the device */
2146 group = make_kgid(current_user_ns(), arg);
2147 if (!gid_valid(group)) {
2148 ret = -EINVAL;
2149 break;
2150 }
2151 tun->group = group;
2152 tun_debug(KERN_INFO, tun, "group set to %u\n",
2153 from_kgid(&init_user_ns, tun->group));
2154 break;
2155
2156 case TUNSETLINK:
2157 /* Only allow setting the type when the interface is down */
2158 if (tun->dev->flags & IFF_UP) {
2159 tun_debug(KERN_INFO, tun,
2160 "Linktype set failed because interface is up\n");
2161 ret = -EBUSY;
2162 } else {
2163 tun->dev->type = (int) arg;
2164 tun_debug(KERN_INFO, tun, "linktype set to %d\n",
2165 tun->dev->type);
2166 ret = 0;
2167 }
2168 break;
2169
2170 #ifdef TUN_DEBUG
2171 case TUNSETDEBUG:
2172 tun->debug = arg;
2173 break;
2174 #endif
2175 case TUNSETOFFLOAD:
2176 ret = set_offload(tun, arg);
2177 break;
2178
2179 case TUNSETTXFILTER:
2180 /* Can be set only for TAPs */
2181 ret = -EINVAL;
2182 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2183 break;
2184 ret = update_filter(&tun->txflt, (void __user *)arg);
2185 break;
2186
2187 case SIOCGIFHWADDR:
2188 /* Get hw address */
2189 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
2190 ifr.ifr_hwaddr.sa_family = tun->dev->type;
2191 if (copy_to_user(argp, &ifr, ifreq_len))
2192 ret = -EFAULT;
2193 break;
2194
2195 case SIOCSIFHWADDR:
2196 /* Set hw address */
2197 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
2198 ifr.ifr_hwaddr.sa_data);
2199
2200 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
2201 break;
2202
2203 case TUNGETSNDBUF:
2204 sndbuf = tfile->socket.sk->sk_sndbuf;
2205 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
2206 ret = -EFAULT;
2207 break;
2208
2209 case TUNSETSNDBUF:
2210 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
2211 ret = -EFAULT;
2212 break;
2213 }
2214
2215 tun->sndbuf = sndbuf;
2216 tun_set_sndbuf(tun);
2217 break;
2218
2219 case TUNGETVNETHDRSZ:
2220 vnet_hdr_sz = tun->vnet_hdr_sz;
2221 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
2222 ret = -EFAULT;
2223 break;
2224
2225 case TUNSETVNETHDRSZ:
2226 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
2227 ret = -EFAULT;
2228 break;
2229 }
2230 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
2231 ret = -EINVAL;
2232 break;
2233 }
2234
2235 tun->vnet_hdr_sz = vnet_hdr_sz;
2236 break;
2237
2238 case TUNGETVNETLE:
2239 le = !!(tun->flags & TUN_VNET_LE);
2240 if (put_user(le, (int __user *)argp))
2241 ret = -EFAULT;
2242 break;
2243
2244 case TUNSETVNETLE:
2245 if (get_user(le, (int __user *)argp)) {
2246 ret = -EFAULT;
2247 break;
2248 }
2249 if (le)
2250 tun->flags |= TUN_VNET_LE;
2251 else
2252 tun->flags &= ~TUN_VNET_LE;
2253 break;
2254
2255 case TUNGETVNETBE:
2256 ret = tun_get_vnet_be(tun, argp);
2257 break;
2258
2259 case TUNSETVNETBE:
2260 ret = tun_set_vnet_be(tun, argp);
2261 break;
2262
2263 case TUNATTACHFILTER:
2264 /* Can be set only for TAPs */
2265 ret = -EINVAL;
2266 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2267 break;
2268 ret = -EFAULT;
2269 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
2270 break;
2271
2272 ret = tun_attach_filter(tun);
2273 break;
2274
2275 case TUNDETACHFILTER:
2276 /* Can be set only for TAPs */
2277 ret = -EINVAL;
2278 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2279 break;
2280 ret = 0;
2281 tun_detach_filter(tun, tun->numqueues);
2282 break;
2283
2284 case TUNGETFILTER:
2285 ret = -EINVAL;
2286 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2287 break;
2288 ret = -EFAULT;
2289 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
2290 break;
2291 ret = 0;
2292 break;
2293
2294 default:
2295 ret = -EINVAL;
2296 break;
2297 }
2298
2299 unlock:
2300 rtnl_unlock();
2301 if (tun)
2302 tun_put(tun);
2303 return ret;
2304 }
2305
2306 static long tun_chr_ioctl(struct file *file,
2307 unsigned int cmd, unsigned long arg)
2308 {
2309 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
2310 }
2311
2312 #ifdef CONFIG_COMPAT
2313 static long tun_chr_compat_ioctl(struct file *file,
2314 unsigned int cmd, unsigned long arg)
2315 {
2316 switch (cmd) {
2317 case TUNSETIFF:
2318 case TUNGETIFF:
2319 case TUNSETTXFILTER:
2320 case TUNGETSNDBUF:
2321 case TUNSETSNDBUF:
2322 case SIOCGIFHWADDR:
2323 case SIOCSIFHWADDR:
2324 arg = (unsigned long)compat_ptr(arg);
2325 break;
2326 default:
2327 arg = (compat_ulong_t)arg;
2328 break;
2329 }
2330
2331 /*
2332 * compat_ifreq is shorter than ifreq, so we must not access beyond
2333 * the end of that structure. All fields that are used in this
2334 * driver are compatible though, we don't need to convert the
2335 * contents.
2336 */
2337 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
2338 }
2339 #endif /* CONFIG_COMPAT */
2340
2341 static int tun_chr_fasync(int fd, struct file *file, int on)
2342 {
2343 struct tun_file *tfile = file->private_data;
2344 int ret;
2345
2346 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
2347 goto out;
2348
2349 if (on) {
2350 __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
2351 tfile->flags |= TUN_FASYNC;
2352 } else
2353 tfile->flags &= ~TUN_FASYNC;
2354 ret = 0;
2355 out:
2356 return ret;
2357 }
2358
2359 static int tun_chr_open(struct inode *inode, struct file * file)
2360 {
2361 struct net *net = current->nsproxy->net_ns;
2362 struct tun_file *tfile;
2363
2364 DBG1(KERN_INFO, "tunX: tun_chr_open\n");
2365
2366 tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
2367 &tun_proto, 0);
2368 if (!tfile)
2369 return -ENOMEM;
2370 RCU_INIT_POINTER(tfile->tun, NULL);
2371 tfile->flags = 0;
2372 tfile->ifindex = 0;
2373
2374 init_waitqueue_head(&tfile->wq.wait);
2375 RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq);
2376
2377 tfile->socket.file = file;
2378 tfile->socket.ops = &tun_socket_ops;
2379
2380 sock_init_data(&tfile->socket, &tfile->sk);
2381
2382 tfile->sk.sk_write_space = tun_sock_write_space;
2383 tfile->sk.sk_sndbuf = INT_MAX;
2384
2385 file->private_data = tfile;
2386 INIT_LIST_HEAD(&tfile->next);
2387
2388 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
2389
2390 return 0;
2391 }
2392
2393 static int tun_chr_close(struct inode *inode, struct file *file)
2394 {
2395 struct tun_file *tfile = file->private_data;
2396
2397 tun_detach(tfile, true);
2398
2399 return 0;
2400 }
2401
2402 #ifdef CONFIG_PROC_FS
2403 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *f)
2404 {
2405 struct tun_struct *tun;
2406 struct ifreq ifr;
2407
2408 memset(&ifr, 0, sizeof(ifr));
2409
2410 rtnl_lock();
2411 tun = tun_get(f);
2412 if (tun)
2413 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2414 rtnl_unlock();
2415
2416 if (tun)
2417 tun_put(tun);
2418
2419 seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
2420 }
2421 #endif
2422
2423 static const struct file_operations tun_fops = {
2424 .owner = THIS_MODULE,
2425 .llseek = no_llseek,
2426 .read_iter = tun_chr_read_iter,
2427 .write_iter = tun_chr_write_iter,
2428 .poll = tun_chr_poll,
2429 .unlocked_ioctl = tun_chr_ioctl,
2430 #ifdef CONFIG_COMPAT
2431 .compat_ioctl = tun_chr_compat_ioctl,
2432 #endif
2433 .open = tun_chr_open,
2434 .release = tun_chr_close,
2435 .fasync = tun_chr_fasync,
2436 #ifdef CONFIG_PROC_FS
2437 .show_fdinfo = tun_chr_show_fdinfo,
2438 #endif
2439 };
2440
2441 static struct miscdevice tun_miscdev = {
2442 .minor = TUN_MINOR,
2443 .name = "tun",
2444 .nodename = "net/tun",
2445 .fops = &tun_fops,
2446 };
2447
2448 /* ethtool interface */
2449
2450 static int tun_get_link_ksettings(struct net_device *dev,
2451 struct ethtool_link_ksettings *cmd)
2452 {
2453 ethtool_link_ksettings_zero_link_mode(cmd, supported);
2454 ethtool_link_ksettings_zero_link_mode(cmd, advertising);
2455 cmd->base.speed = SPEED_10;
2456 cmd->base.duplex = DUPLEX_FULL;
2457 cmd->base.port = PORT_TP;
2458 cmd->base.phy_address = 0;
2459 cmd->base.autoneg = AUTONEG_DISABLE;
2460 return 0;
2461 }
2462
2463 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
2464 {
2465 struct tun_struct *tun = netdev_priv(dev);
2466
2467 strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
2468 strlcpy(info->version, DRV_VERSION, sizeof(info->version));
2469
2470 switch (tun->flags & TUN_TYPE_MASK) {
2471 case IFF_TUN:
2472 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
2473 break;
2474 case IFF_TAP:
2475 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
2476 break;
2477 }
2478 }
2479
2480 static u32 tun_get_msglevel(struct net_device *dev)
2481 {
2482 #ifdef TUN_DEBUG
2483 struct tun_struct *tun = netdev_priv(dev);
2484 return tun->debug;
2485 #else
2486 return -EOPNOTSUPP;
2487 #endif
2488 }
2489
2490 static void tun_set_msglevel(struct net_device *dev, u32 value)
2491 {
2492 #ifdef TUN_DEBUG
2493 struct tun_struct *tun = netdev_priv(dev);
2494 tun->debug = value;
2495 #endif
2496 }
2497
2498 static int tun_get_coalesce(struct net_device *dev,
2499 struct ethtool_coalesce *ec)
2500 {
2501 struct tun_struct *tun = netdev_priv(dev);
2502
2503 ec->rx_max_coalesced_frames = tun->rx_batched;
2504
2505 return 0;
2506 }
2507
2508 static int tun_set_coalesce(struct net_device *dev,
2509 struct ethtool_coalesce *ec)
2510 {
2511 struct tun_struct *tun = netdev_priv(dev);
2512
2513 if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT)
2514 tun->rx_batched = NAPI_POLL_WEIGHT;
2515 else
2516 tun->rx_batched = ec->rx_max_coalesced_frames;
2517
2518 return 0;
2519 }
2520
2521 static const struct ethtool_ops tun_ethtool_ops = {
2522 .get_drvinfo = tun_get_drvinfo,
2523 .get_msglevel = tun_get_msglevel,
2524 .set_msglevel = tun_set_msglevel,
2525 .get_link = ethtool_op_get_link,
2526 .get_ts_info = ethtool_op_get_ts_info,
2527 .get_coalesce = tun_get_coalesce,
2528 .set_coalesce = tun_set_coalesce,
2529 .get_link_ksettings = tun_get_link_ksettings,
2530 };
2531
2532 static int tun_queue_resize(struct tun_struct *tun)
2533 {
2534 struct net_device *dev = tun->dev;
2535 struct tun_file *tfile;
2536 struct skb_array **arrays;
2537 int n = tun->numqueues + tun->numdisabled;
2538 int ret, i;
2539
2540 arrays = kmalloc(sizeof *arrays * n, GFP_KERNEL);
2541 if (!arrays)
2542 return -ENOMEM;
2543
2544 for (i = 0; i < tun->numqueues; i++) {
2545 tfile = rtnl_dereference(tun->tfiles[i]);
2546 arrays[i] = &tfile->tx_array;
2547 }
2548 list_for_each_entry(tfile, &tun->disabled, next)
2549 arrays[i++] = &tfile->tx_array;
2550
2551 ret = skb_array_resize_multiple(arrays, n,
2552 dev->tx_queue_len, GFP_KERNEL);
2553
2554 kfree(arrays);
2555 return ret;
2556 }
2557
2558 static int tun_device_event(struct notifier_block *unused,
2559 unsigned long event, void *ptr)
2560 {
2561 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
2562 struct tun_struct *tun = netdev_priv(dev);
2563
2564 if (dev->rtnl_link_ops != &tun_link_ops)
2565 return NOTIFY_DONE;
2566
2567 switch (event) {
2568 case NETDEV_CHANGE_TX_QUEUE_LEN:
2569 if (tun_queue_resize(tun))
2570 return NOTIFY_BAD;
2571 break;
2572 default:
2573 break;
2574 }
2575
2576 return NOTIFY_DONE;
2577 }
2578
2579 static struct notifier_block tun_notifier_block __read_mostly = {
2580 .notifier_call = tun_device_event,
2581 };
2582
2583 static int __init tun_init(void)
2584 {
2585 int ret = 0;
2586
2587 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
2588
2589 ret = rtnl_link_register(&tun_link_ops);
2590 if (ret) {
2591 pr_err("Can't register link_ops\n");
2592 goto err_linkops;
2593 }
2594
2595 ret = misc_register(&tun_miscdev);
2596 if (ret) {
2597 pr_err("Can't register misc device %d\n", TUN_MINOR);
2598 goto err_misc;
2599 }
2600
2601 register_netdevice_notifier(&tun_notifier_block);
2602 return 0;
2603 err_misc:
2604 rtnl_link_unregister(&tun_link_ops);
2605 err_linkops:
2606 return ret;
2607 }
2608
2609 static void tun_cleanup(void)
2610 {
2611 misc_deregister(&tun_miscdev);
2612 rtnl_link_unregister(&tun_link_ops);
2613 unregister_netdevice_notifier(&tun_notifier_block);
2614 }
2615
2616 /* Get an underlying socket object from tun file. Returns error unless file is
2617 * attached to a device. The returned object works like a packet socket, it
2618 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
2619 * holding a reference to the file for as long as the socket is in use. */
2620 struct socket *tun_get_socket(struct file *file)
2621 {
2622 struct tun_file *tfile;
2623 if (file->f_op != &tun_fops)
2624 return ERR_PTR(-EINVAL);
2625 tfile = file->private_data;
2626 if (!tfile)
2627 return ERR_PTR(-EBADFD);
2628 return &tfile->socket;
2629 }
2630 EXPORT_SYMBOL_GPL(tun_get_socket);
2631
2632 struct skb_array *tun_get_skb_array(struct file *file)
2633 {
2634 struct tun_file *tfile;
2635
2636 if (file->f_op != &tun_fops)
2637 return ERR_PTR(-EINVAL);
2638 tfile = file->private_data;
2639 if (!tfile)
2640 return ERR_PTR(-EBADFD);
2641 return &tfile->tx_array;
2642 }
2643 EXPORT_SYMBOL_GPL(tun_get_skb_array);
2644
2645 module_init(tun_init);
2646 module_exit(tun_cleanup);
2647 MODULE_DESCRIPTION(DRV_DESCRIPTION);
2648 MODULE_AUTHOR(DRV_COPYRIGHT);
2649 MODULE_LICENSE("GPL");
2650 MODULE_ALIAS_MISCDEV(TUN_MINOR);
2651 MODULE_ALIAS("devname:net/tun");
Linux with added FPC-III support