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tun: unbreak truncated packet signalling
[linux-2.6/btrfs-unstable.git] / drivers / net / tun.c
blob7c8343a4f91823a579910cbcccc5827a2eb1d986
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
73 #include <asm/uaccess.h>
74
75 /* Uncomment to enable debugging */
76 /* #define TUN_DEBUG 1 */
77
78 #ifdef TUN_DEBUG
79 static int debug;
80
81 #define tun_debug(level, tun, fmt, args...) \
82 do { \
83 if (tun->debug) \
84 netdev_printk(level, tun->dev, fmt, ##args); \
85 } while (0)
86 #define DBG1(level, fmt, args...) \
87 do { \
88 if (debug == 2) \
89 printk(level fmt, ##args); \
90 } while (0)
91 #else
92 #define tun_debug(level, tun, fmt, args...) \
93 do { \
94 if (0) \
95 netdev_printk(level, tun->dev, fmt, ##args); \
96 } while (0)
97 #define DBG1(level, fmt, args...) \
98 do { \
99 if (0) \
100 printk(level fmt, ##args); \
101 } while (0)
102 #endif
103
104 #define GOODCOPY_LEN 128
105
106 #define FLT_EXACT_COUNT 8
107 struct tap_filter {
108 unsigned int count; /* Number of addrs. Zero means disabled */
109 u32 mask[2]; /* Mask of the hashed addrs */
110 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
111 };
112
113 /* DEFAULT_MAX_NUM_RSS_QUEUES were choosed to let the rx/tx queues allocated for
114 * the netdevice to be fit in one page. So we can make sure the success of
115 * memory allocation. TODO: increase the limit. */
116 #define MAX_TAP_QUEUES DEFAULT_MAX_NUM_RSS_QUEUES
117 #define MAX_TAP_FLOWS 4096
118
119 #define TUN_FLOW_EXPIRE (3 * HZ)
120
121 /* A tun_file connects an open character device to a tuntap netdevice. It
122 * also contains all socket related strctures (except sock_fprog and tap_filter)
123 * to serve as one transmit queue for tuntap device. The sock_fprog and
124 * tap_filter were kept in tun_struct since they were used for filtering for the
125 * netdevice not for a specific queue (at least I didn't see the requirement for
126 * this).
127 *
128 * RCU usage:
129 * The tun_file and tun_struct are loosely coupled, the pointer from one to the
130 * other can only be read while rcu_read_lock or rtnl_lock is held.
131 */
132 struct tun_file {
133 struct sock sk;
134 struct socket socket;
135 struct socket_wq wq;
136 struct tun_struct __rcu *tun;
137 struct net *net;
138 struct fasync_struct *fasync;
139 /* only used for fasnyc */
140 unsigned int flags;
141 union {
142 u16 queue_index;
143 unsigned int ifindex;
144 };
145 struct list_head next;
146 struct tun_struct *detached;
147 };
148
149 struct tun_flow_entry {
150 struct hlist_node hash_link;
151 struct rcu_head rcu;
152 struct tun_struct *tun;
153
154 u32 rxhash;
155 int queue_index;
156 unsigned long updated;
157 };
158
159 #define TUN_NUM_FLOW_ENTRIES 1024
160
161 /* Since the socket were moved to tun_file, to preserve the behavior of persist
162 * device, socket filter, sndbuf and vnet header size were restore when the
163 * file were attached to a persist device.
164 */
165 struct tun_struct {
166 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES];
167 unsigned int numqueues;
168 unsigned int flags;
169 kuid_t owner;
170 kgid_t group;
171
172 struct net_device *dev;
173 netdev_features_t set_features;
174 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
175 NETIF_F_TSO6|NETIF_F_UFO)
176
177 int vnet_hdr_sz;
178 int sndbuf;
179 struct tap_filter txflt;
180 struct sock_fprog fprog;
181 /* protected by rtnl lock */
182 bool filter_attached;
183 #ifdef TUN_DEBUG
184 int debug;
185 #endif
186 spinlock_t lock;
187 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
188 struct timer_list flow_gc_timer;
189 unsigned long ageing_time;
190 unsigned int numdisabled;
191 struct list_head disabled;
192 void *security;
193 u32 flow_count;
194 };
195
196 static inline u32 tun_hashfn(u32 rxhash)
197 {
198 return rxhash & 0x3ff;
199 }
200
201 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
202 {
203 struct tun_flow_entry *e;
204
205 hlist_for_each_entry_rcu(e, head, hash_link) {
206 if (e->rxhash == rxhash)
207 return e;
208 }
209 return NULL;
210 }
211
212 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
213 struct hlist_head *head,
214 u32 rxhash, u16 queue_index)
215 {
216 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
217
218 if (e) {
219 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
220 rxhash, queue_index);
221 e->updated = jiffies;
222 e->rxhash = rxhash;
223 e->queue_index = queue_index;
224 e->tun = tun;
225 hlist_add_head_rcu(&e->hash_link, head);
226 ++tun->flow_count;
227 }
228 return e;
229 }
230
231 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
232 {
233 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
234 e->rxhash, e->queue_index);
235 hlist_del_rcu(&e->hash_link);
236 kfree_rcu(e, rcu);
237 --tun->flow_count;
238 }
239
240 static void tun_flow_flush(struct tun_struct *tun)
241 {
242 int i;
243
244 spin_lock_bh(&tun->lock);
245 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
246 struct tun_flow_entry *e;
247 struct hlist_node *n;
248
249 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
250 tun_flow_delete(tun, e);
251 }
252 spin_unlock_bh(&tun->lock);
253 }
254
255 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
256 {
257 int i;
258
259 spin_lock_bh(&tun->lock);
260 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
261 struct tun_flow_entry *e;
262 struct hlist_node *n;
263
264 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
265 if (e->queue_index == queue_index)
266 tun_flow_delete(tun, e);
267 }
268 }
269 spin_unlock_bh(&tun->lock);
270 }
271
272 static void tun_flow_cleanup(unsigned long data)
273 {
274 struct tun_struct *tun = (struct tun_struct *)data;
275 unsigned long delay = tun->ageing_time;
276 unsigned long next_timer = jiffies + delay;
277 unsigned long count = 0;
278 int i;
279
280 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
281
282 spin_lock_bh(&tun->lock);
283 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
284 struct tun_flow_entry *e;
285 struct hlist_node *n;
286
287 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
288 unsigned long this_timer;
289 count++;
290 this_timer = e->updated + delay;
291 if (time_before_eq(this_timer, jiffies))
292 tun_flow_delete(tun, e);
293 else if (time_before(this_timer, next_timer))
294 next_timer = this_timer;
295 }
296 }
297
298 if (count)
299 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
300 spin_unlock_bh(&tun->lock);
301 }
302
303 static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
304 struct tun_file *tfile)
305 {
306 struct hlist_head *head;
307 struct tun_flow_entry *e;
308 unsigned long delay = tun->ageing_time;
309 u16 queue_index = tfile->queue_index;
310
311 if (!rxhash)
312 return;
313 else
314 head = &tun->flows[tun_hashfn(rxhash)];
315
316 rcu_read_lock();
317
318 /* We may get a very small possibility of OOO during switching, not
319 * worth to optimize.*/
320 if (tun->numqueues == 1 || tfile->detached)
321 goto unlock;
322
323 e = tun_flow_find(head, rxhash);
324 if (likely(e)) {
325 /* TODO: keep queueing to old queue until it's empty? */
326 e->queue_index = queue_index;
327 e->updated = jiffies;
328 } else {
329 spin_lock_bh(&tun->lock);
330 if (!tun_flow_find(head, rxhash) &&
331 tun->flow_count < MAX_TAP_FLOWS)
332 tun_flow_create(tun, head, rxhash, queue_index);
333
334 if (!timer_pending(&tun->flow_gc_timer))
335 mod_timer(&tun->flow_gc_timer,
336 round_jiffies_up(jiffies + delay));
337 spin_unlock_bh(&tun->lock);
338 }
339
340 unlock:
341 rcu_read_unlock();
342 }
343
344 /* We try to identify a flow through its rxhash first. The reason that
345 * we do not check rxq no. is becuase some cards(e.g 82599), chooses
346 * the rxq based on the txq where the last packet of the flow comes. As
347 * the userspace application move between processors, we may get a
348 * different rxq no. here. If we could not get rxhash, then we would
349 * hope the rxq no. may help here.
350 */
351 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb)
352 {
353 struct tun_struct *tun = netdev_priv(dev);
354 struct tun_flow_entry *e;
355 u32 txq = 0;
356 u32 numqueues = 0;
357
358 rcu_read_lock();
359 numqueues = ACCESS_ONCE(tun->numqueues);
360
361 txq = skb_get_rxhash(skb);
362 if (txq) {
363 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
364 if (e)
365 txq = e->queue_index;
366 else
367 /* use multiply and shift instead of expensive divide */
368 txq = ((u64)txq * numqueues) >> 32;
369 } else if (likely(skb_rx_queue_recorded(skb))) {
370 txq = skb_get_rx_queue(skb);
371 while (unlikely(txq >= numqueues))
372 txq -= numqueues;
373 }
374
375 rcu_read_unlock();
376 return txq;
377 }
378
379 static inline bool tun_not_capable(struct tun_struct *tun)
380 {
381 const struct cred *cred = current_cred();
382 struct net *net = dev_net(tun->dev);
383
384 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
385 (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
386 !ns_capable(net->user_ns, CAP_NET_ADMIN);
387 }
388
389 static void tun_set_real_num_queues(struct tun_struct *tun)
390 {
391 netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
392 netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
393 }
394
395 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
396 {
397 tfile->detached = tun;
398 list_add_tail(&tfile->next, &tun->disabled);
399 ++tun->numdisabled;
400 }
401
402 static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
403 {
404 struct tun_struct *tun = tfile->detached;
405
406 tfile->detached = NULL;
407 list_del_init(&tfile->next);
408 --tun->numdisabled;
409 return tun;
410 }
411
412 static void tun_queue_purge(struct tun_file *tfile)
413 {
414 skb_queue_purge(&tfile->sk.sk_receive_queue);
415 skb_queue_purge(&tfile->sk.sk_error_queue);
416 }
417
418 static void __tun_detach(struct tun_file *tfile, bool clean)
419 {
420 struct tun_file *ntfile;
421 struct tun_struct *tun;
422
423 tun = rtnl_dereference(tfile->tun);
424
425 if (tun && !tfile->detached) {
426 u16 index = tfile->queue_index;
427 BUG_ON(index >= tun->numqueues);
428
429 rcu_assign_pointer(tun->tfiles[index],
430 tun->tfiles[tun->numqueues - 1]);
431 ntfile = rtnl_dereference(tun->tfiles[index]);
432 ntfile->queue_index = index;
433
434 --tun->numqueues;
435 if (clean) {
436 rcu_assign_pointer(tfile->tun, NULL);
437 sock_put(&tfile->sk);
438 } else
439 tun_disable_queue(tun, tfile);
440
441 synchronize_net();
442 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
443 /* Drop read queue */
444 tun_queue_purge(tfile);
445 tun_set_real_num_queues(tun);
446 } else if (tfile->detached && clean) {
447 tun = tun_enable_queue(tfile);
448 sock_put(&tfile->sk);
449 }
450
451 if (clean) {
452 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
453 netif_carrier_off(tun->dev);
454
455 if (!(tun->flags & TUN_PERSIST) &&
456 tun->dev->reg_state == NETREG_REGISTERED)
457 unregister_netdevice(tun->dev);
458 }
459
460 BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED,
461 &tfile->socket.flags));
462 sk_release_kernel(&tfile->sk);
463 }
464 }
465
466 static void tun_detach(struct tun_file *tfile, bool clean)
467 {
468 rtnl_lock();
469 __tun_detach(tfile, clean);
470 rtnl_unlock();
471 }
472
473 static void tun_detach_all(struct net_device *dev)
474 {
475 struct tun_struct *tun = netdev_priv(dev);
476 struct tun_file *tfile, *tmp;
477 int i, n = tun->numqueues;
478
479 for (i = 0; i < n; i++) {
480 tfile = rtnl_dereference(tun->tfiles[i]);
481 BUG_ON(!tfile);
482 wake_up_all(&tfile->wq.wait);
483 rcu_assign_pointer(tfile->tun, NULL);
484 --tun->numqueues;
485 }
486 list_for_each_entry(tfile, &tun->disabled, next) {
487 wake_up_all(&tfile->wq.wait);
488 rcu_assign_pointer(tfile->tun, NULL);
489 }
490 BUG_ON(tun->numqueues != 0);
491
492 synchronize_net();
493 for (i = 0; i < n; i++) {
494 tfile = rtnl_dereference(tun->tfiles[i]);
495 /* Drop read queue */
496 tun_queue_purge(tfile);
497 sock_put(&tfile->sk);
498 }
499 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
500 tun_enable_queue(tfile);
501 tun_queue_purge(tfile);
502 sock_put(&tfile->sk);
503 }
504 BUG_ON(tun->numdisabled != 0);
505
506 if (tun->flags & TUN_PERSIST)
507 module_put(THIS_MODULE);
508 }
509
510 static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter)
511 {
512 struct tun_file *tfile = file->private_data;
513 int err;
514
515 err = security_tun_dev_attach(tfile->socket.sk, tun->security);
516 if (err < 0)
517 goto out;
518
519 err = -EINVAL;
520 if (rtnl_dereference(tfile->tun) && !tfile->detached)
521 goto out;
522
523 err = -EBUSY;
524 if (!(tun->flags & TUN_TAP_MQ) && tun->numqueues == 1)
525 goto out;
526
527 err = -E2BIG;
528 if (!tfile->detached &&
529 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
530 goto out;
531
532 err = 0;
533
534 /* Re-attach the filter to presist device */
535 if (!skip_filter && (tun->filter_attached == true)) {
536 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
537 if (!err)
538 goto out;
539 }
540 tfile->queue_index = tun->numqueues;
541 rcu_assign_pointer(tfile->tun, tun);
542 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
543 tun->numqueues++;
544
545 if (tfile->detached)
546 tun_enable_queue(tfile);
547 else
548 sock_hold(&tfile->sk);
549
550 tun_set_real_num_queues(tun);
551
552 /* device is allowed to go away first, so no need to hold extra
553 * refcnt.
554 */
555
556 out:
557 return err;
558 }
559
560 static struct tun_struct *__tun_get(struct tun_file *tfile)
561 {
562 struct tun_struct *tun;
563
564 rcu_read_lock();
565 tun = rcu_dereference(tfile->tun);
566 if (tun)
567 dev_hold(tun->dev);
568 rcu_read_unlock();
569
570 return tun;
571 }
572
573 static struct tun_struct *tun_get(struct file *file)
574 {
575 return __tun_get(file->private_data);
576 }
577
578 static void tun_put(struct tun_struct *tun)
579 {
580 dev_put(tun->dev);
581 }
582
583 /* TAP filtering */
584 static void addr_hash_set(u32 *mask, const u8 *addr)
585 {
586 int n = ether_crc(ETH_ALEN, addr) >> 26;
587 mask[n >> 5] |= (1 << (n & 31));
588 }
589
590 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
591 {
592 int n = ether_crc(ETH_ALEN, addr) >> 26;
593 return mask[n >> 5] & (1 << (n & 31));
594 }
595
596 static int update_filter(struct tap_filter *filter, void __user *arg)
597 {
598 struct { u8 u[ETH_ALEN]; } *addr;
599 struct tun_filter uf;
600 int err, alen, n, nexact;
601
602 if (copy_from_user(&uf, arg, sizeof(uf)))
603 return -EFAULT;
604
605 if (!uf.count) {
606 /* Disabled */
607 filter->count = 0;
608 return 0;
609 }
610
611 alen = ETH_ALEN * uf.count;
612 addr = kmalloc(alen, GFP_KERNEL);
613 if (!addr)
614 return -ENOMEM;
615
616 if (copy_from_user(addr, arg + sizeof(uf), alen)) {
617 err = -EFAULT;
618 goto done;
619 }
620
621 /* The filter is updated without holding any locks. Which is
622 * perfectly safe. We disable it first and in the worst
623 * case we'll accept a few undesired packets. */
624 filter->count = 0;
625 wmb();
626
627 /* Use first set of addresses as an exact filter */
628 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
629 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
630
631 nexact = n;
632
633 /* Remaining multicast addresses are hashed,
634 * unicast will leave the filter disabled. */
635 memset(filter->mask, 0, sizeof(filter->mask));
636 for (; n < uf.count; n++) {
637 if (!is_multicast_ether_addr(addr[n].u)) {
638 err = 0; /* no filter */
639 goto done;
640 }
641 addr_hash_set(filter->mask, addr[n].u);
642 }
643
644 /* For ALLMULTI just set the mask to all ones.
645 * This overrides the mask populated above. */
646 if ((uf.flags & TUN_FLT_ALLMULTI))
647 memset(filter->mask, ~0, sizeof(filter->mask));
648
649 /* Now enable the filter */
650 wmb();
651 filter->count = nexact;
652
653 /* Return the number of exact filters */
654 err = nexact;
655
656 done:
657 kfree(addr);
658 return err;
659 }
660
661 /* Returns: 0 - drop, !=0 - accept */
662 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
663 {
664 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
665 * at this point. */
666 struct ethhdr *eh = (struct ethhdr *) skb->data;
667 int i;
668
669 /* Exact match */
670 for (i = 0; i < filter->count; i++)
671 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
672 return 1;
673
674 /* Inexact match (multicast only) */
675 if (is_multicast_ether_addr(eh->h_dest))
676 return addr_hash_test(filter->mask, eh->h_dest);
677
678 return 0;
679 }
680
681 /*
682 * Checks whether the packet is accepted or not.
683 * Returns: 0 - drop, !=0 - accept
684 */
685 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
686 {
687 if (!filter->count)
688 return 1;
689
690 return run_filter(filter, skb);
691 }
692
693 /* Network device part of the driver */
694
695 static const struct ethtool_ops tun_ethtool_ops;
696
697 /* Net device detach from fd. */
698 static void tun_net_uninit(struct net_device *dev)
699 {
700 tun_detach_all(dev);
701 }
702
703 /* Net device open. */
704 static int tun_net_open(struct net_device *dev)
705 {
706 netif_tx_start_all_queues(dev);
707 return 0;
708 }
709
710 /* Net device close. */
711 static int tun_net_close(struct net_device *dev)
712 {
713 netif_tx_stop_all_queues(dev);
714 return 0;
715 }
716
717 /* Net device start xmit */
718 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
719 {
720 struct tun_struct *tun = netdev_priv(dev);
721 int txq = skb->queue_mapping;
722 struct tun_file *tfile;
723
724 rcu_read_lock();
725 tfile = rcu_dereference(tun->tfiles[txq]);
726
727 /* Drop packet if interface is not attached */
728 if (txq >= tun->numqueues)
729 goto drop;
730
731 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
732
733 BUG_ON(!tfile);
734
735 /* Drop if the filter does not like it.
736 * This is a noop if the filter is disabled.
737 * Filter can be enabled only for the TAP devices. */
738 if (!check_filter(&tun->txflt, skb))
739 goto drop;
740
741 if (tfile->socket.sk->sk_filter &&
742 sk_filter(tfile->socket.sk, skb))
743 goto drop;
744
745 /* Limit the number of packets queued by dividing txq length with the
746 * number of queues.
747 */
748 if (skb_queue_len(&tfile->socket.sk->sk_receive_queue)
749 >= dev->tx_queue_len / tun->numqueues)
750 goto drop;
751
752 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
753 goto drop;
754
755 if (skb->sk) {
756 sock_tx_timestamp(skb->sk, &skb_shinfo(skb)->tx_flags);
757 sw_tx_timestamp(skb);
758 }
759
760 /* Orphan the skb - required as we might hang on to it
761 * for indefinite time.
762 */
763 skb_orphan(skb);
764
765 nf_reset(skb);
766
767 /* Enqueue packet */
768 skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb);
769
770 /* Notify and wake up reader process */
771 if (tfile->flags & TUN_FASYNC)
772 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
773 wake_up_interruptible_poll(&tfile->wq.wait, POLLIN |
774 POLLRDNORM | POLLRDBAND);
775
776 rcu_read_unlock();
777 return NETDEV_TX_OK;
778
779 drop:
780 dev->stats.tx_dropped++;
781 skb_tx_error(skb);
782 kfree_skb(skb);
783 rcu_read_unlock();
784 return NETDEV_TX_OK;
785 }
786
787 static void tun_net_mclist(struct net_device *dev)
788 {
789 /*
790 * This callback is supposed to deal with mc filter in
791 * _rx_ path and has nothing to do with the _tx_ path.
792 * In rx path we always accept everything userspace gives us.
793 */
794 }
795
796 #define MIN_MTU 68
797 #define MAX_MTU 65535
798
799 static int
800 tun_net_change_mtu(struct net_device *dev, int new_mtu)
801 {
802 if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
803 return -EINVAL;
804 dev->mtu = new_mtu;
805 return 0;
806 }
807
808 static netdev_features_t tun_net_fix_features(struct net_device *dev,
809 netdev_features_t features)
810 {
811 struct tun_struct *tun = netdev_priv(dev);
812
813 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
814 }
815 #ifdef CONFIG_NET_POLL_CONTROLLER
816 static void tun_poll_controller(struct net_device *dev)
817 {
818 /*
819 * Tun only receives frames when:
820 * 1) the char device endpoint gets data from user space
821 * 2) the tun socket gets a sendmsg call from user space
822 * Since both of those are syncronous operations, we are guaranteed
823 * never to have pending data when we poll for it
824 * so theres nothing to do here but return.
825 * We need this though so netpoll recognizes us as an interface that
826 * supports polling, which enables bridge devices in virt setups to
827 * still use netconsole
828 */
829 return;
830 }
831 #endif
832 static const struct net_device_ops tun_netdev_ops = {
833 .ndo_uninit = tun_net_uninit,
834 .ndo_open = tun_net_open,
835 .ndo_stop = tun_net_close,
836 .ndo_start_xmit = tun_net_xmit,
837 .ndo_change_mtu = tun_net_change_mtu,
838 .ndo_fix_features = tun_net_fix_features,
839 .ndo_select_queue = tun_select_queue,
840 #ifdef CONFIG_NET_POLL_CONTROLLER
841 .ndo_poll_controller = tun_poll_controller,
842 #endif
843 };
844
845 static const struct net_device_ops tap_netdev_ops = {
846 .ndo_uninit = tun_net_uninit,
847 .ndo_open = tun_net_open,
848 .ndo_stop = tun_net_close,
849 .ndo_start_xmit = tun_net_xmit,
850 .ndo_change_mtu = tun_net_change_mtu,
851 .ndo_fix_features = tun_net_fix_features,
852 .ndo_set_rx_mode = tun_net_mclist,
853 .ndo_set_mac_address = eth_mac_addr,
854 .ndo_validate_addr = eth_validate_addr,
855 .ndo_select_queue = tun_select_queue,
856 #ifdef CONFIG_NET_POLL_CONTROLLER
857 .ndo_poll_controller = tun_poll_controller,
858 #endif
859 };
860
861 static void tun_flow_init(struct tun_struct *tun)
862 {
863 int i;
864
865 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
866 INIT_HLIST_HEAD(&tun->flows[i]);
867
868 tun->ageing_time = TUN_FLOW_EXPIRE;
869 setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun);
870 mod_timer(&tun->flow_gc_timer,
871 round_jiffies_up(jiffies + tun->ageing_time));
872 }
873
874 static void tun_flow_uninit(struct tun_struct *tun)
875 {
876 del_timer_sync(&tun->flow_gc_timer);
877 tun_flow_flush(tun);
878 }
879
880 /* Initialize net device. */
881 static void tun_net_init(struct net_device *dev)
882 {
883 struct tun_struct *tun = netdev_priv(dev);
884
885 switch (tun->flags & TUN_TYPE_MASK) {
886 case TUN_TUN_DEV:
887 dev->netdev_ops = &tun_netdev_ops;
888
889 /* Point-to-Point TUN Device */
890 dev->hard_header_len = 0;
891 dev->addr_len = 0;
892 dev->mtu = 1500;
893
894 /* Zero header length */
895 dev->type = ARPHRD_NONE;
896 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
897 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */
898 break;
899
900 case TUN_TAP_DEV:
901 dev->netdev_ops = &tap_netdev_ops;
902 /* Ethernet TAP Device */
903 ether_setup(dev);
904 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
905 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
906
907 eth_hw_addr_random(dev);
908
909 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */
910 break;
911 }
912 }
913
914 /* Character device part */
915
916 /* Poll */
917 static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
918 {
919 struct tun_file *tfile = file->private_data;
920 struct tun_struct *tun = __tun_get(tfile);
921 struct sock *sk;
922 unsigned int mask = 0;
923
924 if (!tun)
925 return POLLERR;
926
927 sk = tfile->socket.sk;
928
929 tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
930
931 poll_wait(file, &tfile->wq.wait, wait);
932
933 if (!skb_queue_empty(&sk->sk_receive_queue))
934 mask |= POLLIN | POLLRDNORM;
935
936 if (sock_writeable(sk) ||
937 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
938 sock_writeable(sk)))
939 mask |= POLLOUT | POLLWRNORM;
940
941 if (tun->dev->reg_state != NETREG_REGISTERED)
942 mask = POLLERR;
943
944 tun_put(tun);
945 return mask;
946 }
947
948 /* prepad is the amount to reserve at front. len is length after that.
949 * linear is a hint as to how much to copy (usually headers). */
950 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
951 size_t prepad, size_t len,
952 size_t linear, int noblock)
953 {
954 struct sock *sk = tfile->socket.sk;
955 struct sk_buff *skb;
956 int err;
957
958 /* Under a page? Don't bother with paged skb. */
959 if (prepad + len < PAGE_SIZE || !linear)
960 linear = len;
961
962 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
963 &err, 0);
964 if (!skb)
965 return ERR_PTR(err);
966
967 skb_reserve(skb, prepad);
968 skb_put(skb, linear);
969 skb->data_len = len - linear;
970 skb->len += len - linear;
971
972 return skb;
973 }
974
975 /* Get packet from user space buffer */
976 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
977 void *msg_control, const struct iovec *iv,
978 size_t total_len, size_t count, int noblock)
979 {
980 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
981 struct sk_buff *skb;
982 size_t len = total_len, align = NET_SKB_PAD, linear;
983 struct virtio_net_hdr gso = { 0 };
984 int good_linear;
985 int offset = 0;
986 int copylen;
987 bool zerocopy = false;
988 int err;
989 u32 rxhash;
990
991 if (!(tun->flags & TUN_NO_PI)) {
992 if (len < sizeof(pi))
993 return -EINVAL;
994 len -= sizeof(pi);
995
996 if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
997 return -EFAULT;
998 offset += sizeof(pi);
999 }
1000
1001 if (tun->flags & TUN_VNET_HDR) {
1002 if (len < tun->vnet_hdr_sz)
1003 return -EINVAL;
1004 len -= tun->vnet_hdr_sz;
1005
1006 if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
1007 return -EFAULT;
1008
1009 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1010 gso.csum_start + gso.csum_offset + 2 > gso.hdr_len)
1011 gso.hdr_len = gso.csum_start + gso.csum_offset + 2;
1012
1013 if (gso.hdr_len > len)
1014 return -EINVAL;
1015 offset += tun->vnet_hdr_sz;
1016 }
1017
1018 if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
1019 align += NET_IP_ALIGN;
1020 if (unlikely(len < ETH_HLEN ||
1021 (gso.hdr_len && gso.hdr_len < ETH_HLEN)))
1022 return -EINVAL;
1023 }
1024
1025 good_linear = SKB_MAX_HEAD(align);
1026
1027 if (msg_control) {
1028 /* There are 256 bytes to be copied in skb, so there is
1029 * enough room for skb expand head in case it is used.
1030 * The rest of the buffer is mapped from userspace.
1031 */
1032 copylen = gso.hdr_len ? gso.hdr_len : GOODCOPY_LEN;
1033 if (copylen > good_linear)
1034 copylen = good_linear;
1035 linear = copylen;
1036 if (iov_pages(iv, offset + copylen, count) <= MAX_SKB_FRAGS)
1037 zerocopy = true;
1038 }
1039
1040 if (!zerocopy) {
1041 copylen = len;
1042 if (gso.hdr_len > good_linear)
1043 linear = good_linear;
1044 else
1045 linear = gso.hdr_len;
1046 }
1047
1048 skb = tun_alloc_skb(tfile, align, copylen, linear, noblock);
1049 if (IS_ERR(skb)) {
1050 if (PTR_ERR(skb) != -EAGAIN)
1051 tun->dev->stats.rx_dropped++;
1052 return PTR_ERR(skb);
1053 }
1054
1055 if (zerocopy)
1056 err = zerocopy_sg_from_iovec(skb, iv, offset, count);
1057 else {
1058 err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len);
1059 if (!err && msg_control) {
1060 struct ubuf_info *uarg = msg_control;
1061 uarg->callback(uarg, false);
1062 }
1063 }
1064
1065 if (err) {
1066 tun->dev->stats.rx_dropped++;
1067 kfree_skb(skb);
1068 return -EFAULT;
1069 }
1070
1071 if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
1072 if (!skb_partial_csum_set(skb, gso.csum_start,
1073 gso.csum_offset)) {
1074 tun->dev->stats.rx_frame_errors++;
1075 kfree_skb(skb);
1076 return -EINVAL;
1077 }
1078 }
1079
1080 switch (tun->flags & TUN_TYPE_MASK) {
1081 case TUN_TUN_DEV:
1082 if (tun->flags & TUN_NO_PI) {
1083 switch (skb->data[0] & 0xf0) {
1084 case 0x40:
1085 pi.proto = htons(ETH_P_IP);
1086 break;
1087 case 0x60:
1088 pi.proto = htons(ETH_P_IPV6);
1089 break;
1090 default:
1091 tun->dev->stats.rx_dropped++;
1092 kfree_skb(skb);
1093 return -EINVAL;
1094 }
1095 }
1096
1097 skb_reset_mac_header(skb);
1098 skb->protocol = pi.proto;
1099 skb->dev = tun->dev;
1100 break;
1101 case TUN_TAP_DEV:
1102 skb->protocol = eth_type_trans(skb, tun->dev);
1103 break;
1104 }
1105
1106 if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
1107 pr_debug("GSO!\n");
1108 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
1109 case VIRTIO_NET_HDR_GSO_TCPV4:
1110 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1111 break;
1112 case VIRTIO_NET_HDR_GSO_TCPV6:
1113 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
1114 break;
1115 case VIRTIO_NET_HDR_GSO_UDP:
1116 skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1117 break;
1118 default:
1119 tun->dev->stats.rx_frame_errors++;
1120 kfree_skb(skb);
1121 return -EINVAL;
1122 }
1123
1124 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
1125 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
1126
1127 skb_shinfo(skb)->gso_size = gso.gso_size;
1128 if (skb_shinfo(skb)->gso_size == 0) {
1129 tun->dev->stats.rx_frame_errors++;
1130 kfree_skb(skb);
1131 return -EINVAL;
1132 }
1133
1134 /* Header must be checked, and gso_segs computed. */
1135 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
1136 skb_shinfo(skb)->gso_segs = 0;
1137 }
1138
1139 /* copy skb_ubuf_info for callback when skb has no error */
1140 if (zerocopy) {
1141 skb_shinfo(skb)->destructor_arg = msg_control;
1142 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1143 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1144 }
1145
1146 skb_reset_network_header(skb);
1147 skb_probe_transport_header(skb, 0);
1148
1149 rxhash = skb_get_rxhash(skb);
1150 netif_rx_ni(skb);
1151
1152 tun->dev->stats.rx_packets++;
1153 tun->dev->stats.rx_bytes += len;
1154
1155 tun_flow_update(tun, rxhash, tfile);
1156 return total_len;
1157 }
1158
1159 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
1160 unsigned long count, loff_t pos)
1161 {
1162 struct file *file = iocb->ki_filp;
1163 struct tun_struct *tun = tun_get(file);
1164 struct tun_file *tfile = file->private_data;
1165 ssize_t result;
1166
1167 if (!tun)
1168 return -EBADFD;
1169
1170 tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count);
1171
1172 result = tun_get_user(tun, tfile, NULL, iv, iov_length(iv, count),
1173 count, file->f_flags & O_NONBLOCK);
1174
1175 tun_put(tun);
1176 return result;
1177 }
1178
1179 /* Put packet to the user space buffer */
1180 static ssize_t tun_put_user(struct tun_struct *tun,
1181 struct tun_file *tfile,
1182 struct sk_buff *skb,
1183 const struct iovec *iv, int len)
1184 {
1185 struct tun_pi pi = { 0, skb->protocol };
1186 ssize_t total = 0;
1187 int vlan_offset = 0, copied;
1188
1189 if (!(tun->flags & TUN_NO_PI)) {
1190 if ((len -= sizeof(pi)) < 0)
1191 return -EINVAL;
1192
1193 if (len < skb->len) {
1194 /* Packet will be striped */
1195 pi.flags |= TUN_PKT_STRIP;
1196 }
1197
1198 if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi)))
1199 return -EFAULT;
1200 total += sizeof(pi);
1201 }
1202
1203 if (tun->flags & TUN_VNET_HDR) {
1204 struct virtio_net_hdr gso = { 0 }; /* no info leak */
1205 if ((len -= tun->vnet_hdr_sz) < 0)
1206 return -EINVAL;
1207
1208 if (skb_is_gso(skb)) {
1209 struct skb_shared_info *sinfo = skb_shinfo(skb);
1210
1211 /* This is a hint as to how much should be linear. */
1212 gso.hdr_len = skb_headlen(skb);
1213 gso.gso_size = sinfo->gso_size;
1214 if (sinfo->gso_type & SKB_GSO_TCPV4)
1215 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
1216 else if (sinfo->gso_type & SKB_GSO_TCPV6)
1217 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
1218 else if (sinfo->gso_type & SKB_GSO_UDP)
1219 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
1220 else {
1221 pr_err("unexpected GSO type: "
1222 "0x%x, gso_size %d, hdr_len %d\n",
1223 sinfo->gso_type, gso.gso_size,
1224 gso.hdr_len);
1225 print_hex_dump(KERN_ERR, "tun: ",
1226 DUMP_PREFIX_NONE,
1227 16, 1, skb->head,
1228 min((int)gso.hdr_len, 64), true);
1229 WARN_ON_ONCE(1);
1230 return -EINVAL;
1231 }
1232 if (sinfo->gso_type & SKB_GSO_TCP_ECN)
1233 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
1234 } else
1235 gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
1236
1237 if (skb->ip_summed == CHECKSUM_PARTIAL) {
1238 gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
1239 gso.csum_start = skb_checksum_start_offset(skb);
1240 gso.csum_offset = skb->csum_offset;
1241 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
1242 gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
1243 } /* else everything is zero */
1244
1245 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total,
1246 sizeof(gso))))
1247 return -EFAULT;
1248 total += tun->vnet_hdr_sz;
1249 }
1250
1251 copied = total;
1252 total += skb->len;
1253 if (!vlan_tx_tag_present(skb)) {
1254 len = min_t(int, skb->len, len);
1255 } else {
1256 int copy, ret;
1257 struct {
1258 __be16 h_vlan_proto;
1259 __be16 h_vlan_TCI;
1260 } veth;
1261
1262 veth.h_vlan_proto = skb->vlan_proto;
1263 veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb));
1264
1265 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
1266 len = min_t(int, skb->len + VLAN_HLEN, len);
1267 total += VLAN_HLEN;
1268
1269 copy = min_t(int, vlan_offset, len);
1270 ret = skb_copy_datagram_const_iovec(skb, 0, iv, copied, copy);
1271 len -= copy;
1272 copied += copy;
1273 if (ret || !len)
1274 goto done;
1275
1276 copy = min_t(int, sizeof(veth), len);
1277 ret = memcpy_toiovecend(iv, (void *)&veth, copied, copy);
1278 len -= copy;
1279 copied += copy;
1280 if (ret || !len)
1281 goto done;
1282 }
1283
1284 skb_copy_datagram_const_iovec(skb, vlan_offset, iv, copied, len);
1285
1286 done:
1287 tun->dev->stats.tx_packets++;
1288 tun->dev->stats.tx_bytes += len;
1289
1290 return total;
1291 }
1292
1293 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
1294 struct kiocb *iocb, const struct iovec *iv,
1295 ssize_t len, int noblock)
1296 {
1297 DECLARE_WAITQUEUE(wait, current);
1298 struct sk_buff *skb;
1299 ssize_t ret = 0;
1300
1301 tun_debug(KERN_INFO, tun, "tun_do_read\n");
1302
1303 if (unlikely(!noblock))
1304 add_wait_queue(&tfile->wq.wait, &wait);
1305 while (len) {
1306 if (unlikely(!noblock))
1307 current->state = TASK_INTERRUPTIBLE;
1308
1309 /* Read frames from the queue */
1310 if (!(skb = skb_dequeue(&tfile->socket.sk->sk_receive_queue))) {
1311 if (noblock) {
1312 ret = -EAGAIN;
1313 break;
1314 }
1315 if (signal_pending(current)) {
1316 ret = -ERESTARTSYS;
1317 break;
1318 }
1319 if (tun->dev->reg_state != NETREG_REGISTERED) {
1320 ret = -EIO;
1321 break;
1322 }
1323
1324 /* Nothing to read, let's sleep */
1325 schedule();
1326 continue;
1327 }
1328
1329 ret = tun_put_user(tun, tfile, skb, iv, len);
1330 kfree_skb(skb);
1331 break;
1332 }
1333
1334 if (unlikely(!noblock)) {
1335 current->state = TASK_RUNNING;
1336 remove_wait_queue(&tfile->wq.wait, &wait);
1337 }
1338
1339 return ret;
1340 }
1341
1342 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
1343 unsigned long count, loff_t pos)
1344 {
1345 struct file *file = iocb->ki_filp;
1346 struct tun_file *tfile = file->private_data;
1347 struct tun_struct *tun = __tun_get(tfile);
1348 ssize_t len, ret;
1349
1350 if (!tun)
1351 return -EBADFD;
1352 len = iov_length(iv, count);
1353 if (len < 0) {
1354 ret = -EINVAL;
1355 goto out;
1356 }
1357
1358 ret = tun_do_read(tun, tfile, iocb, iv, len,
1359 file->f_flags & O_NONBLOCK);
1360 ret = min_t(ssize_t, ret, len);
1361 if (ret > 0)
1362 iocb->ki_pos = ret;
1363 out:
1364 tun_put(tun);
1365 return ret;
1366 }
1367
1368 static void tun_free_netdev(struct net_device *dev)
1369 {
1370 struct tun_struct *tun = netdev_priv(dev);
1371
1372 BUG_ON(!(list_empty(&tun->disabled)));
1373 tun_flow_uninit(tun);
1374 security_tun_dev_free_security(tun->security);
1375 free_netdev(dev);
1376 }
1377
1378 static void tun_setup(struct net_device *dev)
1379 {
1380 struct tun_struct *tun = netdev_priv(dev);
1381
1382 tun->owner = INVALID_UID;
1383 tun->group = INVALID_GID;
1384
1385 dev->ethtool_ops = &tun_ethtool_ops;
1386 dev->destructor = tun_free_netdev;
1387 }
1388
1389 /* Trivial set of netlink ops to allow deleting tun or tap
1390 * device with netlink.
1391 */
1392 static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
1393 {
1394 return -EINVAL;
1395 }
1396
1397 static struct rtnl_link_ops tun_link_ops __read_mostly = {
1398 .kind = DRV_NAME,
1399 .priv_size = sizeof(struct tun_struct),
1400 .setup = tun_setup,
1401 .validate = tun_validate,
1402 };
1403
1404 static void tun_sock_write_space(struct sock *sk)
1405 {
1406 struct tun_file *tfile;
1407 wait_queue_head_t *wqueue;
1408
1409 if (!sock_writeable(sk))
1410 return;
1411
1412 if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
1413 return;
1414
1415 wqueue = sk_sleep(sk);
1416 if (wqueue && waitqueue_active(wqueue))
1417 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1418 POLLWRNORM | POLLWRBAND);
1419
1420 tfile = container_of(sk, struct tun_file, sk);
1421 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
1422 }
1423
1424 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock,
1425 struct msghdr *m, size_t total_len)
1426 {
1427 int ret;
1428 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1429 struct tun_struct *tun = __tun_get(tfile);
1430
1431 if (!tun)
1432 return -EBADFD;
1433 ret = tun_get_user(tun, tfile, m->msg_control, m->msg_iov, total_len,
1434 m->msg_iovlen, m->msg_flags & MSG_DONTWAIT);
1435 tun_put(tun);
1436 return ret;
1437 }
1438
1439 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
1440 struct msghdr *m, size_t total_len,
1441 int flags)
1442 {
1443 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1444 struct tun_struct *tun = __tun_get(tfile);
1445 int ret;
1446
1447 if (!tun)
1448 return -EBADFD;
1449
1450 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
1451 ret = -EINVAL;
1452 goto out;
1453 }
1454 if (flags & MSG_ERRQUEUE) {
1455 ret = sock_recv_errqueue(sock->sk, m, total_len,
1456 SOL_PACKET, TUN_TX_TIMESTAMP);
1457 goto out;
1458 }
1459 ret = tun_do_read(tun, tfile, iocb, m->msg_iov, total_len,
1460 flags & MSG_DONTWAIT);
1461 if (ret > total_len) {
1462 m->msg_flags |= MSG_TRUNC;
1463 ret = flags & MSG_TRUNC ? ret : total_len;
1464 }
1465 out:
1466 tun_put(tun);
1467 return ret;
1468 }
1469
1470 static int tun_release(struct socket *sock)
1471 {
1472 if (sock->sk)
1473 sock_put(sock->sk);
1474 return 0;
1475 }
1476
1477 /* Ops structure to mimic raw sockets with tun */
1478 static const struct proto_ops tun_socket_ops = {
1479 .sendmsg = tun_sendmsg,
1480 .recvmsg = tun_recvmsg,
1481 .release = tun_release,
1482 };
1483
1484 static struct proto tun_proto = {
1485 .name = "tun",
1486 .owner = THIS_MODULE,
1487 .obj_size = sizeof(struct tun_file),
1488 };
1489
1490 static int tun_flags(struct tun_struct *tun)
1491 {
1492 int flags = 0;
1493
1494 if (tun->flags & TUN_TUN_DEV)
1495 flags |= IFF_TUN;
1496 else
1497 flags |= IFF_TAP;
1498
1499 if (tun->flags & TUN_NO_PI)
1500 flags |= IFF_NO_PI;
1501
1502 /* This flag has no real effect. We track the value for backwards
1503 * compatibility.
1504 */
1505 if (tun->flags & TUN_ONE_QUEUE)
1506 flags |= IFF_ONE_QUEUE;
1507
1508 if (tun->flags & TUN_VNET_HDR)
1509 flags |= IFF_VNET_HDR;
1510
1511 if (tun->flags & TUN_TAP_MQ)
1512 flags |= IFF_MULTI_QUEUE;
1513
1514 if (tun->flags & TUN_PERSIST)
1515 flags |= IFF_PERSIST;
1516
1517 return flags;
1518 }
1519
1520 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1521 char *buf)
1522 {
1523 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1524 return sprintf(buf, "0x%x\n", tun_flags(tun));
1525 }
1526
1527 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1528 char *buf)
1529 {
1530 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1531 return uid_valid(tun->owner)?
1532 sprintf(buf, "%u\n",
1533 from_kuid_munged(current_user_ns(), tun->owner)):
1534 sprintf(buf, "-1\n");
1535 }
1536
1537 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1538 char *buf)
1539 {
1540 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1541 return gid_valid(tun->group) ?
1542 sprintf(buf, "%u\n",
1543 from_kgid_munged(current_user_ns(), tun->group)):
1544 sprintf(buf, "-1\n");
1545 }
1546
1547 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1548 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1549 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1550
1551 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1552 {
1553 struct tun_struct *tun;
1554 struct tun_file *tfile = file->private_data;
1555 struct net_device *dev;
1556 int err;
1557
1558 if (tfile->detached)
1559 return -EINVAL;
1560
1561 dev = __dev_get_by_name(net, ifr->ifr_name);
1562 if (dev) {
1563 if (ifr->ifr_flags & IFF_TUN_EXCL)
1564 return -EBUSY;
1565 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1566 tun = netdev_priv(dev);
1567 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1568 tun = netdev_priv(dev);
1569 else
1570 return -EINVAL;
1571
1572 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
1573 !!(tun->flags & TUN_TAP_MQ))
1574 return -EINVAL;
1575
1576 if (tun_not_capable(tun))
1577 return -EPERM;
1578 err = security_tun_dev_open(tun->security);
1579 if (err < 0)
1580 return err;
1581
1582 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER);
1583 if (err < 0)
1584 return err;
1585
1586 if (tun->flags & TUN_TAP_MQ &&
1587 (tun->numqueues + tun->numdisabled > 1)) {
1588 /* One or more queue has already been attached, no need
1589 * to initialize the device again.
1590 */
1591 return 0;
1592 }
1593 }
1594 else {
1595 char *name;
1596 unsigned long flags = 0;
1597 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
1598 MAX_TAP_QUEUES : 1;
1599
1600 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1601 return -EPERM;
1602 err = security_tun_dev_create();
1603 if (err < 0)
1604 return err;
1605
1606 /* Set dev type */
1607 if (ifr->ifr_flags & IFF_TUN) {
1608 /* TUN device */
1609 flags |= TUN_TUN_DEV;
1610 name = "tun%d";
1611 } else if (ifr->ifr_flags & IFF_TAP) {
1612 /* TAP device */
1613 flags |= TUN_TAP_DEV;
1614 name = "tap%d";
1615 } else
1616 return -EINVAL;
1617
1618 if (*ifr->ifr_name)
1619 name = ifr->ifr_name;
1620
1621 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
1622 tun_setup, queues, queues);
1623
1624 if (!dev)
1625 return -ENOMEM;
1626
1627 dev_net_set(dev, net);
1628 dev->rtnl_link_ops = &tun_link_ops;
1629 dev->ifindex = tfile->ifindex;
1630
1631 tun = netdev_priv(dev);
1632 tun->dev = dev;
1633 tun->flags = flags;
1634 tun->txflt.count = 0;
1635 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1636
1637 tun->filter_attached = false;
1638 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
1639
1640 spin_lock_init(&tun->lock);
1641
1642 err = security_tun_dev_alloc_security(&tun->security);
1643 if (err < 0)
1644 goto err_free_dev;
1645
1646 tun_net_init(dev);
1647 tun_flow_init(tun);
1648
1649 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1650 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
1651 NETIF_F_HW_VLAN_STAG_TX;
1652 dev->features = dev->hw_features;
1653 dev->vlan_features = dev->features;
1654
1655 INIT_LIST_HEAD(&tun->disabled);
1656 err = tun_attach(tun, file, false);
1657 if (err < 0)
1658 goto err_free_flow;
1659
1660 err = register_netdevice(tun->dev);
1661 if (err < 0)
1662 goto err_detach;
1663
1664 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) ||
1665 device_create_file(&tun->dev->dev, &dev_attr_owner) ||
1666 device_create_file(&tun->dev->dev, &dev_attr_group))
1667 pr_err("Failed to create tun sysfs files\n");
1668 }
1669
1670 netif_carrier_on(tun->dev);
1671
1672 tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1673
1674 if (ifr->ifr_flags & IFF_NO_PI)
1675 tun->flags |= TUN_NO_PI;
1676 else
1677 tun->flags &= ~TUN_NO_PI;
1678
1679 /* This flag has no real effect. We track the value for backwards
1680 * compatibility.
1681 */
1682 if (ifr->ifr_flags & IFF_ONE_QUEUE)
1683 tun->flags |= TUN_ONE_QUEUE;
1684 else
1685 tun->flags &= ~TUN_ONE_QUEUE;
1686
1687 if (ifr->ifr_flags & IFF_VNET_HDR)
1688 tun->flags |= TUN_VNET_HDR;
1689 else
1690 tun->flags &= ~TUN_VNET_HDR;
1691
1692 if (ifr->ifr_flags & IFF_MULTI_QUEUE)
1693 tun->flags |= TUN_TAP_MQ;
1694 else
1695 tun->flags &= ~TUN_TAP_MQ;
1696
1697 /* Make sure persistent devices do not get stuck in
1698 * xoff state.
1699 */
1700 if (netif_running(tun->dev))
1701 netif_tx_wake_all_queues(tun->dev);
1702
1703 strcpy(ifr->ifr_name, tun->dev->name);
1704 return 0;
1705
1706 err_detach:
1707 tun_detach_all(dev);
1708 err_free_flow:
1709 tun_flow_uninit(tun);
1710 security_tun_dev_free_security(tun->security);
1711 err_free_dev:
1712 free_netdev(dev);
1713 return err;
1714 }
1715
1716 static void tun_get_iff(struct net *net, struct tun_struct *tun,
1717 struct ifreq *ifr)
1718 {
1719 tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1720
1721 strcpy(ifr->ifr_name, tun->dev->name);
1722
1723 ifr->ifr_flags = tun_flags(tun);
1724
1725 }
1726
1727 /* This is like a cut-down ethtool ops, except done via tun fd so no
1728 * privs required. */
1729 static int set_offload(struct tun_struct *tun, unsigned long arg)
1730 {
1731 netdev_features_t features = 0;
1732
1733 if (arg & TUN_F_CSUM) {
1734 features |= NETIF_F_HW_CSUM;
1735 arg &= ~TUN_F_CSUM;
1736
1737 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1738 if (arg & TUN_F_TSO_ECN) {
1739 features |= NETIF_F_TSO_ECN;
1740 arg &= ~TUN_F_TSO_ECN;
1741 }
1742 if (arg & TUN_F_TSO4)
1743 features |= NETIF_F_TSO;
1744 if (arg & TUN_F_TSO6)
1745 features |= NETIF_F_TSO6;
1746 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1747 }
1748
1749 if (arg & TUN_F_UFO) {
1750 features |= NETIF_F_UFO;
1751 arg &= ~TUN_F_UFO;
1752 }
1753 }
1754
1755 /* This gives the user a way to test for new features in future by
1756 * trying to set them. */
1757 if (arg)
1758 return -EINVAL;
1759
1760 tun->set_features = features;
1761 netdev_update_features(tun->dev);
1762
1763 return 0;
1764 }
1765
1766 static void tun_detach_filter(struct tun_struct *tun, int n)
1767 {
1768 int i;
1769 struct tun_file *tfile;
1770
1771 for (i = 0; i < n; i++) {
1772 tfile = rtnl_dereference(tun->tfiles[i]);
1773 sk_detach_filter(tfile->socket.sk);
1774 }
1775
1776 tun->filter_attached = false;
1777 }
1778
1779 static int tun_attach_filter(struct tun_struct *tun)
1780 {
1781 int i, ret = 0;
1782 struct tun_file *tfile;
1783
1784 for (i = 0; i < tun->numqueues; i++) {
1785 tfile = rtnl_dereference(tun->tfiles[i]);
1786 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
1787 if (ret) {
1788 tun_detach_filter(tun, i);
1789 return ret;
1790 }
1791 }
1792
1793 tun->filter_attached = true;
1794 return ret;
1795 }
1796
1797 static void tun_set_sndbuf(struct tun_struct *tun)
1798 {
1799 struct tun_file *tfile;
1800 int i;
1801
1802 for (i = 0; i < tun->numqueues; i++) {
1803 tfile = rtnl_dereference(tun->tfiles[i]);
1804 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
1805 }
1806 }
1807
1808 static int tun_set_queue(struct file *file, struct ifreq *ifr)
1809 {
1810 struct tun_file *tfile = file->private_data;
1811 struct tun_struct *tun;
1812 int ret = 0;
1813
1814 rtnl_lock();
1815
1816 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
1817 tun = tfile->detached;
1818 if (!tun) {
1819 ret = -EINVAL;
1820 goto unlock;
1821 }
1822 ret = security_tun_dev_attach_queue(tun->security);
1823 if (ret < 0)
1824 goto unlock;
1825 ret = tun_attach(tun, file, false);
1826 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
1827 tun = rtnl_dereference(tfile->tun);
1828 if (!tun || !(tun->flags & TUN_TAP_MQ) || tfile->detached)
1829 ret = -EINVAL;
1830 else
1831 __tun_detach(tfile, false);
1832 } else
1833 ret = -EINVAL;
1834
1835 unlock:
1836 rtnl_unlock();
1837 return ret;
1838 }
1839
1840 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1841 unsigned long arg, int ifreq_len)
1842 {
1843 struct tun_file *tfile = file->private_data;
1844 struct tun_struct *tun;
1845 void __user* argp = (void __user*)arg;
1846 struct ifreq ifr;
1847 kuid_t owner;
1848 kgid_t group;
1849 int sndbuf;
1850 int vnet_hdr_sz;
1851 unsigned int ifindex;
1852 int ret;
1853
1854 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) {
1855 if (copy_from_user(&ifr, argp, ifreq_len))
1856 return -EFAULT;
1857 } else {
1858 memset(&ifr, 0, sizeof(ifr));
1859 }
1860 if (cmd == TUNGETFEATURES) {
1861 /* Currently this just means: "what IFF flags are valid?".
1862 * This is needed because we never checked for invalid flags on
1863 * TUNSETIFF. */
1864 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
1865 IFF_VNET_HDR | IFF_MULTI_QUEUE,
1866 (unsigned int __user*)argp);
1867 } else if (cmd == TUNSETQUEUE)
1868 return tun_set_queue(file, &ifr);
1869
1870 ret = 0;
1871 rtnl_lock();
1872
1873 tun = __tun_get(tfile);
1874 if (cmd == TUNSETIFF && !tun) {
1875 ifr.ifr_name[IFNAMSIZ-1] = '\0';
1876
1877 ret = tun_set_iff(tfile->net, file, &ifr);
1878
1879 if (ret)
1880 goto unlock;
1881
1882 if (copy_to_user(argp, &ifr, ifreq_len))
1883 ret = -EFAULT;
1884 goto unlock;
1885 }
1886 if (cmd == TUNSETIFINDEX) {
1887 ret = -EPERM;
1888 if (tun)
1889 goto unlock;
1890
1891 ret = -EFAULT;
1892 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
1893 goto unlock;
1894
1895 ret = 0;
1896 tfile->ifindex = ifindex;
1897 goto unlock;
1898 }
1899
1900 ret = -EBADFD;
1901 if (!tun)
1902 goto unlock;
1903
1904 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
1905
1906 ret = 0;
1907 switch (cmd) {
1908 case TUNGETIFF:
1909 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1910
1911 if (tfile->detached)
1912 ifr.ifr_flags |= IFF_DETACH_QUEUE;
1913 if (!tfile->socket.sk->sk_filter)
1914 ifr.ifr_flags |= IFF_NOFILTER;
1915
1916 if (copy_to_user(argp, &ifr, ifreq_len))
1917 ret = -EFAULT;
1918 break;
1919
1920 case TUNSETNOCSUM:
1921 /* Disable/Enable checksum */
1922
1923 /* [unimplemented] */
1924 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
1925 arg ? "disabled" : "enabled");
1926 break;
1927
1928 case TUNSETPERSIST:
1929 /* Disable/Enable persist mode. Keep an extra reference to the
1930 * module to prevent the module being unprobed.
1931 */
1932 if (arg && !(tun->flags & TUN_PERSIST)) {
1933 tun->flags |= TUN_PERSIST;
1934 __module_get(THIS_MODULE);
1935 }
1936 if (!arg && (tun->flags & TUN_PERSIST)) {
1937 tun->flags &= ~TUN_PERSIST;
1938 module_put(THIS_MODULE);
1939 }
1940
1941 tun_debug(KERN_INFO, tun, "persist %s\n",
1942 arg ? "enabled" : "disabled");
1943 break;
1944
1945 case TUNSETOWNER:
1946 /* Set owner of the device */
1947 owner = make_kuid(current_user_ns(), arg);
1948 if (!uid_valid(owner)) {
1949 ret = -EINVAL;
1950 break;
1951 }
1952 tun->owner = owner;
1953 tun_debug(KERN_INFO, tun, "owner set to %u\n",
1954 from_kuid(&init_user_ns, tun->owner));
1955 break;
1956
1957 case TUNSETGROUP:
1958 /* Set group of the device */
1959 group = make_kgid(current_user_ns(), arg);
1960 if (!gid_valid(group)) {
1961 ret = -EINVAL;
1962 break;
1963 }
1964 tun->group = group;
1965 tun_debug(KERN_INFO, tun, "group set to %u\n",
1966 from_kgid(&init_user_ns, tun->group));
1967 break;
1968
1969 case TUNSETLINK:
1970 /* Only allow setting the type when the interface is down */
1971 if (tun->dev->flags & IFF_UP) {
1972 tun_debug(KERN_INFO, tun,
1973 "Linktype set failed because interface is up\n");
1974 ret = -EBUSY;
1975 } else {
1976 tun->dev->type = (int) arg;
1977 tun_debug(KERN_INFO, tun, "linktype set to %d\n",
1978 tun->dev->type);
1979 ret = 0;
1980 }
1981 break;
1982
1983 #ifdef TUN_DEBUG
1984 case TUNSETDEBUG:
1985 tun->debug = arg;
1986 break;
1987 #endif
1988 case TUNSETOFFLOAD:
1989 ret = set_offload(tun, arg);
1990 break;
1991
1992 case TUNSETTXFILTER:
1993 /* Can be set only for TAPs */
1994 ret = -EINVAL;
1995 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1996 break;
1997 ret = update_filter(&tun->txflt, (void __user *)arg);
1998 break;
1999
2000 case SIOCGIFHWADDR:
2001 /* Get hw address */
2002 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
2003 ifr.ifr_hwaddr.sa_family = tun->dev->type;
2004 if (copy_to_user(argp, &ifr, ifreq_len))
2005 ret = -EFAULT;
2006 break;
2007
2008 case SIOCSIFHWADDR:
2009 /* Set hw address */
2010 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
2011 ifr.ifr_hwaddr.sa_data);
2012
2013 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
2014 break;
2015
2016 case TUNGETSNDBUF:
2017 sndbuf = tfile->socket.sk->sk_sndbuf;
2018 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
2019 ret = -EFAULT;
2020 break;
2021
2022 case TUNSETSNDBUF:
2023 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
2024 ret = -EFAULT;
2025 break;
2026 }
2027
2028 tun->sndbuf = sndbuf;
2029 tun_set_sndbuf(tun);
2030 break;
2031
2032 case TUNGETVNETHDRSZ:
2033 vnet_hdr_sz = tun->vnet_hdr_sz;
2034 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
2035 ret = -EFAULT;
2036 break;
2037
2038 case TUNSETVNETHDRSZ:
2039 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
2040 ret = -EFAULT;
2041 break;
2042 }
2043 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
2044 ret = -EINVAL;
2045 break;
2046 }
2047
2048 tun->vnet_hdr_sz = vnet_hdr_sz;
2049 break;
2050
2051 case TUNATTACHFILTER:
2052 /* Can be set only for TAPs */
2053 ret = -EINVAL;
2054 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
2055 break;
2056 ret = -EFAULT;
2057 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
2058 break;
2059
2060 ret = tun_attach_filter(tun);
2061 break;
2062
2063 case TUNDETACHFILTER:
2064 /* Can be set only for TAPs */
2065 ret = -EINVAL;
2066 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
2067 break;
2068 ret = 0;
2069 tun_detach_filter(tun, tun->numqueues);
2070 break;
2071
2072 case TUNGETFILTER:
2073 ret = -EINVAL;
2074 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
2075 break;
2076 ret = -EFAULT;
2077 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
2078 break;
2079 ret = 0;
2080 break;
2081
2082 default:
2083 ret = -EINVAL;
2084 break;
2085 }
2086
2087 unlock:
2088 rtnl_unlock();
2089 if (tun)
2090 tun_put(tun);
2091 return ret;
2092 }
2093
2094 static long tun_chr_ioctl(struct file *file,
2095 unsigned int cmd, unsigned long arg)
2096 {
2097 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
2098 }
2099
2100 #ifdef CONFIG_COMPAT
2101 static long tun_chr_compat_ioctl(struct file *file,
2102 unsigned int cmd, unsigned long arg)
2103 {
2104 switch (cmd) {
2105 case TUNSETIFF:
2106 case TUNGETIFF:
2107 case TUNSETTXFILTER:
2108 case TUNGETSNDBUF:
2109 case TUNSETSNDBUF:
2110 case SIOCGIFHWADDR:
2111 case SIOCSIFHWADDR:
2112 arg = (unsigned long)compat_ptr(arg);
2113 break;
2114 default:
2115 arg = (compat_ulong_t)arg;
2116 break;
2117 }
2118
2119 /*
2120 * compat_ifreq is shorter than ifreq, so we must not access beyond
2121 * the end of that structure. All fields that are used in this
2122 * driver are compatible though, we don't need to convert the
2123 * contents.
2124 */
2125 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
2126 }
2127 #endif /* CONFIG_COMPAT */
2128
2129 static int tun_chr_fasync(int fd, struct file *file, int on)
2130 {
2131 struct tun_file *tfile = file->private_data;
2132 int ret;
2133
2134 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
2135 goto out;
2136
2137 if (on) {
2138 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
2139 if (ret)
2140 goto out;
2141 tfile->flags |= TUN_FASYNC;
2142 } else
2143 tfile->flags &= ~TUN_FASYNC;
2144 ret = 0;
2145 out:
2146 return ret;
2147 }
2148
2149 static int tun_chr_open(struct inode *inode, struct file * file)
2150 {
2151 struct tun_file *tfile;
2152
2153 DBG1(KERN_INFO, "tunX: tun_chr_open\n");
2154
2155 tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL,
2156 &tun_proto);
2157 if (!tfile)
2158 return -ENOMEM;
2159 rcu_assign_pointer(tfile->tun, NULL);
2160 tfile->net = get_net(current->nsproxy->net_ns);
2161 tfile->flags = 0;
2162 tfile->ifindex = 0;
2163
2164 rcu_assign_pointer(tfile->socket.wq, &tfile->wq);
2165 init_waitqueue_head(&tfile->wq.wait);
2166
2167 tfile->socket.file = file;
2168 tfile->socket.ops = &tun_socket_ops;
2169
2170 sock_init_data(&tfile->socket, &tfile->sk);
2171 sk_change_net(&tfile->sk, tfile->net);
2172
2173 tfile->sk.sk_write_space = tun_sock_write_space;
2174 tfile->sk.sk_sndbuf = INT_MAX;
2175
2176 file->private_data = tfile;
2177 set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags);
2178 INIT_LIST_HEAD(&tfile->next);
2179
2180 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
2181
2182 return 0;
2183 }
2184
2185 static int tun_chr_close(struct inode *inode, struct file *file)
2186 {
2187 struct tun_file *tfile = file->private_data;
2188 struct net *net = tfile->net;
2189
2190 tun_detach(tfile, true);
2191 put_net(net);
2192
2193 return 0;
2194 }
2195
2196 static const struct file_operations tun_fops = {
2197 .owner = THIS_MODULE,
2198 .llseek = no_llseek,
2199 .read = do_sync_read,
2200 .aio_read = tun_chr_aio_read,
2201 .write = do_sync_write,
2202 .aio_write = tun_chr_aio_write,
2203 .poll = tun_chr_poll,
2204 .unlocked_ioctl = tun_chr_ioctl,
2205 #ifdef CONFIG_COMPAT
2206 .compat_ioctl = tun_chr_compat_ioctl,
2207 #endif
2208 .open = tun_chr_open,
2209 .release = tun_chr_close,
2210 .fasync = tun_chr_fasync
2211 };
2212
2213 static struct miscdevice tun_miscdev = {
2214 .minor = TUN_MINOR,
2215 .name = "tun",
2216 .nodename = "net/tun",
2217 .fops = &tun_fops,
2218 };
2219
2220 /* ethtool interface */
2221
2222 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
2223 {
2224 cmd->supported = 0;
2225 cmd->advertising = 0;
2226 ethtool_cmd_speed_set(cmd, SPEED_10);
2227 cmd->duplex = DUPLEX_FULL;
2228 cmd->port = PORT_TP;
2229 cmd->phy_address = 0;
2230 cmd->transceiver = XCVR_INTERNAL;
2231 cmd->autoneg = AUTONEG_DISABLE;
2232 cmd->maxtxpkt = 0;
2233 cmd->maxrxpkt = 0;
2234 return 0;
2235 }
2236
2237 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
2238 {
2239 struct tun_struct *tun = netdev_priv(dev);
2240
2241 strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
2242 strlcpy(info->version, DRV_VERSION, sizeof(info->version));
2243
2244 switch (tun->flags & TUN_TYPE_MASK) {
2245 case TUN_TUN_DEV:
2246 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
2247 break;
2248 case TUN_TAP_DEV:
2249 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
2250 break;
2251 }
2252 }
2253
2254 static u32 tun_get_msglevel(struct net_device *dev)
2255 {
2256 #ifdef TUN_DEBUG
2257 struct tun_struct *tun = netdev_priv(dev);
2258 return tun->debug;
2259 #else
2260 return -EOPNOTSUPP;
2261 #endif
2262 }
2263
2264 static void tun_set_msglevel(struct net_device *dev, u32 value)
2265 {
2266 #ifdef TUN_DEBUG
2267 struct tun_struct *tun = netdev_priv(dev);
2268 tun->debug = value;
2269 #endif
2270 }
2271
2272 static const struct ethtool_ops tun_ethtool_ops = {
2273 .get_settings = tun_get_settings,
2274 .get_drvinfo = tun_get_drvinfo,
2275 .get_msglevel = tun_get_msglevel,
2276 .set_msglevel = tun_set_msglevel,
2277 .get_link = ethtool_op_get_link,
2278 .get_ts_info = ethtool_op_get_ts_info,
2279 };
2280
2281
2282 static int __init tun_init(void)
2283 {
2284 int ret = 0;
2285
2286 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
2287 pr_info("%s\n", DRV_COPYRIGHT);
2288
2289 ret = rtnl_link_register(&tun_link_ops);
2290 if (ret) {
2291 pr_err("Can't register link_ops\n");
2292 goto err_linkops;
2293 }
2294
2295 ret = misc_register(&tun_miscdev);
2296 if (ret) {
2297 pr_err("Can't register misc device %d\n", TUN_MINOR);
2298 goto err_misc;
2299 }
2300 return 0;
2301 err_misc:
2302 rtnl_link_unregister(&tun_link_ops);
2303 err_linkops:
2304 return ret;
2305 }
2306
2307 static void tun_cleanup(void)
2308 {
2309 misc_deregister(&tun_miscdev);
2310 rtnl_link_unregister(&tun_link_ops);
2311 }
2312
2313 /* Get an underlying socket object from tun file. Returns error unless file is
2314 * attached to a device. The returned object works like a packet socket, it
2315 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
2316 * holding a reference to the file for as long as the socket is in use. */
2317 struct socket *tun_get_socket(struct file *file)
2318 {
2319 struct tun_file *tfile;
2320 if (file->f_op != &tun_fops)
2321 return ERR_PTR(-EINVAL);
2322 tfile = file->private_data;
2323 if (!tfile)
2324 return ERR_PTR(-EBADFD);
2325 return &tfile->socket;
2326 }
2327 EXPORT_SYMBOL_GPL(tun_get_socket);
2328
2329 module_init(tun_init);
2330 module_exit(tun_cleanup);
2331 MODULE_DESCRIPTION(DRV_DESCRIPTION);
2332 MODULE_AUTHOR(DRV_COPYRIGHT);
2333 MODULE_LICENSE("GPL");
2334 MODULE_ALIAS_MISCDEV(TUN_MINOR);
2335 MODULE_ALIAS("devname:net/tun");
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