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hwrng: core - Don't use a stack buffer in add_early_randomness()
[linux/fpc-iii.git] / drivers / net / tun.c
blob8093e39ae263a7bd954682125221189499206b7c
1 /*
2 * TUN - Universal TUN/TAP device driver.
3 * Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
16 */
17
18 /*
19 * Changes:
20 *
21 * Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
22 * Add TUNSETLINK ioctl to set the link encapsulation
23 *
24 * Mark Smith <markzzzsmith@yahoo.com.au>
25 * Use eth_random_addr() for tap MAC address.
26 *
27 * Harald Roelle <harald.roelle@ifi.lmu.de> 2004/04/20
28 * Fixes in packet dropping, queue length setting and queue wakeup.
29 * Increased default tx queue length.
30 * Added ethtool API.
31 * Minor cleanups
32 *
33 * Daniel Podlejski <underley@underley.eu.org>
34 * Modifications for 2.3.99-pre5 kernel.
35 */
36
37 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
38
39 #define DRV_NAME "tun"
40 #define DRV_VERSION "1.6"
41 #define DRV_DESCRIPTION "Universal TUN/TAP device driver"
42 #define DRV_COPYRIGHT "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
43
44 #include <linux/module.h>
45 #include <linux/errno.h>
46 #include <linux/kernel.h>
47 #include <linux/major.h>
48 #include <linux/slab.h>
49 #include <linux/poll.h>
50 #include <linux/fcntl.h>
51 #include <linux/init.h>
52 #include <linux/skbuff.h>
53 #include <linux/netdevice.h>
54 #include <linux/etherdevice.h>
55 #include <linux/miscdevice.h>
56 #include <linux/ethtool.h>
57 #include <linux/rtnetlink.h>
58 #include <linux/compat.h>
59 #include <linux/if.h>
60 #include <linux/if_arp.h>
61 #include <linux/if_ether.h>
62 #include <linux/if_tun.h>
63 #include <linux/if_vlan.h>
64 #include <linux/crc32.h>
65 #include <linux/nsproxy.h>
66 #include <linux/virtio_net.h>
67 #include <linux/rcupdate.h>
68 #include <net/net_namespace.h>
69 #include <net/netns/generic.h>
70 #include <net/rtnetlink.h>
71 #include <net/sock.h>
72 #include <linux/seq_file.h>
73 #include <linux/uio.h>
74 #include <linux/skb_array.h>
75
76 #include <asm/uaccess.h>
77
78 /* Uncomment to enable debugging */
79 /* #define TUN_DEBUG 1 */
80
81 #ifdef TUN_DEBUG
82 static int debug;
83
84 #define tun_debug(level, tun, fmt, args...) \
85 do { \
86 if (tun->debug) \
87 netdev_printk(level, tun->dev, fmt, ##args); \
88 } while (0)
89 #define DBG1(level, fmt, args...) \
90 do { \
91 if (debug == 2) \
92 printk(level fmt, ##args); \
93 } while (0)
94 #else
95 #define tun_debug(level, tun, fmt, args...) \
96 do { \
97 if (0) \
98 netdev_printk(level, tun->dev, fmt, ##args); \
99 } while (0)
100 #define DBG1(level, fmt, args...) \
101 do { \
102 if (0) \
103 printk(level fmt, ##args); \
104 } while (0)
105 #endif
106
107 /* TUN device flags */
108
109 /* IFF_ATTACH_QUEUE is never stored in device flags,
110 * overload it to mean fasync when stored there.
111 */
112 #define TUN_FASYNC IFF_ATTACH_QUEUE
113 /* High bits in flags field are unused. */
114 #define TUN_VNET_LE 0x80000000
115 #define TUN_VNET_BE 0x40000000
116
117 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
118 IFF_MULTI_QUEUE)
119 #define GOODCOPY_LEN 128
120
121 #define FLT_EXACT_COUNT 8
122 struct tap_filter {
123 unsigned int count; /* Number of addrs. Zero means disabled */
124 u32 mask[2]; /* Mask of the hashed addrs */
125 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
126 };
127
128 /* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
129 * to max number of VCPUs in guest. */
130 #define MAX_TAP_QUEUES 256
131 #define MAX_TAP_FLOWS 4096
132
133 #define TUN_FLOW_EXPIRE (3 * HZ)
134
135 struct tun_pcpu_stats {
136 u64 rx_packets;
137 u64 rx_bytes;
138 u64 tx_packets;
139 u64 tx_bytes;
140 struct u64_stats_sync syncp;
141 u32 rx_dropped;
142 u32 tx_dropped;
143 u32 rx_frame_errors;
144 };
145
146 /* A tun_file connects an open character device to a tuntap netdevice. It
147 * also contains all socket related structures (except sock_fprog and tap_filter)
148 * to serve as one transmit queue for tuntap device. The sock_fprog and
149 * tap_filter were kept in tun_struct since they were used for filtering for the
150 * netdevice not for a specific queue (at least I didn't see the requirement for
151 * this).
152 *
153 * RCU usage:
154 * The tun_file and tun_struct are loosely coupled, the pointer from one to the
155 * other can only be read while rcu_read_lock or rtnl_lock is held.
156 */
157 struct tun_file {
158 struct sock sk;
159 struct socket socket;
160 struct socket_wq wq;
161 struct tun_struct __rcu *tun;
162 struct fasync_struct *fasync;
163 /* only used for fasnyc */
164 unsigned int flags;
165 union {
166 u16 queue_index;
167 unsigned int ifindex;
168 };
169 struct list_head next;
170 struct tun_struct *detached;
171 struct skb_array tx_array;
172 };
173
174 struct tun_flow_entry {
175 struct hlist_node hash_link;
176 struct rcu_head rcu;
177 struct tun_struct *tun;
178
179 u32 rxhash;
180 u32 rps_rxhash;
181 int queue_index;
182 unsigned long updated;
183 };
184
185 #define TUN_NUM_FLOW_ENTRIES 1024
186
187 /* Since the socket were moved to tun_file, to preserve the behavior of persist
188 * device, socket filter, sndbuf and vnet header size were restore when the
189 * file were attached to a persist device.
190 */
191 struct tun_struct {
192 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES];
193 unsigned int numqueues;
194 unsigned int flags;
195 kuid_t owner;
196 kgid_t group;
197
198 struct net_device *dev;
199 netdev_features_t set_features;
200 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
201 NETIF_F_TSO6|NETIF_F_UFO)
202
203 int align;
204 int vnet_hdr_sz;
205 int sndbuf;
206 struct tap_filter txflt;
207 struct sock_fprog fprog;
208 /* protected by rtnl lock */
209 bool filter_attached;
210 #ifdef TUN_DEBUG
211 int debug;
212 #endif
213 spinlock_t lock;
214 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
215 struct timer_list flow_gc_timer;
216 unsigned long ageing_time;
217 unsigned int numdisabled;
218 struct list_head disabled;
219 void *security;
220 u32 flow_count;
221 struct tun_pcpu_stats __percpu *pcpu_stats;
222 };
223
224 #ifdef CONFIG_TUN_VNET_CROSS_LE
225 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
226 {
227 return tun->flags & TUN_VNET_BE ? false :
228 virtio_legacy_is_little_endian();
229 }
230
231 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
232 {
233 int be = !!(tun->flags & TUN_VNET_BE);
234
235 if (put_user(be, argp))
236 return -EFAULT;
237
238 return 0;
239 }
240
241 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
242 {
243 int be;
244
245 if (get_user(be, argp))
246 return -EFAULT;
247
248 if (be)
249 tun->flags |= TUN_VNET_BE;
250 else
251 tun->flags &= ~TUN_VNET_BE;
252
253 return 0;
254 }
255 #else
256 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
257 {
258 return virtio_legacy_is_little_endian();
259 }
260
261 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
262 {
263 return -EINVAL;
264 }
265
266 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
267 {
268 return -EINVAL;
269 }
270 #endif /* CONFIG_TUN_VNET_CROSS_LE */
271
272 static inline bool tun_is_little_endian(struct tun_struct *tun)
273 {
274 return tun->flags & TUN_VNET_LE ||
275 tun_legacy_is_little_endian(tun);
276 }
277
278 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
279 {
280 return __virtio16_to_cpu(tun_is_little_endian(tun), val);
281 }
282
283 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
284 {
285 return __cpu_to_virtio16(tun_is_little_endian(tun), val);
286 }
287
288 static inline u32 tun_hashfn(u32 rxhash)
289 {
290 return rxhash & 0x3ff;
291 }
292
293 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
294 {
295 struct tun_flow_entry *e;
296
297 hlist_for_each_entry_rcu(e, head, hash_link) {
298 if (e->rxhash == rxhash)
299 return e;
300 }
301 return NULL;
302 }
303
304 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
305 struct hlist_head *head,
306 u32 rxhash, u16 queue_index)
307 {
308 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
309
310 if (e) {
311 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
312 rxhash, queue_index);
313 e->updated = jiffies;
314 e->rxhash = rxhash;
315 e->rps_rxhash = 0;
316 e->queue_index = queue_index;
317 e->tun = tun;
318 hlist_add_head_rcu(&e->hash_link, head);
319 ++tun->flow_count;
320 }
321 return e;
322 }
323
324 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
325 {
326 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
327 e->rxhash, e->queue_index);
328 hlist_del_rcu(&e->hash_link);
329 kfree_rcu(e, rcu);
330 --tun->flow_count;
331 }
332
333 static void tun_flow_flush(struct tun_struct *tun)
334 {
335 int i;
336
337 spin_lock_bh(&tun->lock);
338 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
339 struct tun_flow_entry *e;
340 struct hlist_node *n;
341
342 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
343 tun_flow_delete(tun, e);
344 }
345 spin_unlock_bh(&tun->lock);
346 }
347
348 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
349 {
350 int i;
351
352 spin_lock_bh(&tun->lock);
353 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
354 struct tun_flow_entry *e;
355 struct hlist_node *n;
356
357 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
358 if (e->queue_index == queue_index)
359 tun_flow_delete(tun, e);
360 }
361 }
362 spin_unlock_bh(&tun->lock);
363 }
364
365 static void tun_flow_cleanup(unsigned long data)
366 {
367 struct tun_struct *tun = (struct tun_struct *)data;
368 unsigned long delay = tun->ageing_time;
369 unsigned long next_timer = jiffies + delay;
370 unsigned long count = 0;
371 int i;
372
373 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
374
375 spin_lock_bh(&tun->lock);
376 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
377 struct tun_flow_entry *e;
378 struct hlist_node *n;
379
380 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
381 unsigned long this_timer;
382 count++;
383 this_timer = e->updated + delay;
384 if (time_before_eq(this_timer, jiffies))
385 tun_flow_delete(tun, e);
386 else if (time_before(this_timer, next_timer))
387 next_timer = this_timer;
388 }
389 }
390
391 if (count)
392 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
393 spin_unlock_bh(&tun->lock);
394 }
395
396 static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
397 struct tun_file *tfile)
398 {
399 struct hlist_head *head;
400 struct tun_flow_entry *e;
401 unsigned long delay = tun->ageing_time;
402 u16 queue_index = tfile->queue_index;
403
404 if (!rxhash)
405 return;
406 else
407 head = &tun->flows[tun_hashfn(rxhash)];
408
409 rcu_read_lock();
410
411 /* We may get a very small possibility of OOO during switching, not
412 * worth to optimize.*/
413 if (tun->numqueues == 1 || tfile->detached)
414 goto unlock;
415
416 e = tun_flow_find(head, rxhash);
417 if (likely(e)) {
418 /* TODO: keep queueing to old queue until it's empty? */
419 e->queue_index = queue_index;
420 e->updated = jiffies;
421 sock_rps_record_flow_hash(e->rps_rxhash);
422 } else {
423 spin_lock_bh(&tun->lock);
424 if (!tun_flow_find(head, rxhash) &&
425 tun->flow_count < MAX_TAP_FLOWS)
426 tun_flow_create(tun, head, rxhash, queue_index);
427
428 if (!timer_pending(&tun->flow_gc_timer))
429 mod_timer(&tun->flow_gc_timer,
430 round_jiffies_up(jiffies + delay));
431 spin_unlock_bh(&tun->lock);
432 }
433
434 unlock:
435 rcu_read_unlock();
436 }
437
438 /**
439 * Save the hash received in the stack receive path and update the
440 * flow_hash table accordingly.
441 */
442 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
443 {
444 if (unlikely(e->rps_rxhash != hash))
445 e->rps_rxhash = hash;
446 }
447
448 /* We try to identify a flow through its rxhash first. The reason that
449 * we do not check rxq no. is because some cards(e.g 82599), chooses
450 * the rxq based on the txq where the last packet of the flow comes. As
451 * the userspace application move between processors, we may get a
452 * different rxq no. here. If we could not get rxhash, then we would
453 * hope the rxq no. may help here.
454 */
455 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
456 void *accel_priv, select_queue_fallback_t fallback)
457 {
458 struct tun_struct *tun = netdev_priv(dev);
459 struct tun_flow_entry *e;
460 u32 txq = 0;
461 u32 numqueues = 0;
462
463 rcu_read_lock();
464 numqueues = ACCESS_ONCE(tun->numqueues);
465
466 txq = skb_get_hash(skb);
467 if (txq) {
468 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
469 if (e) {
470 tun_flow_save_rps_rxhash(e, txq);
471 txq = e->queue_index;
472 } else
473 /* use multiply and shift instead of expensive divide */
474 txq = ((u64)txq * numqueues) >> 32;
475 } else if (likely(skb_rx_queue_recorded(skb))) {
476 txq = skb_get_rx_queue(skb);
477 while (unlikely(txq >= numqueues))
478 txq -= numqueues;
479 }
480
481 rcu_read_unlock();
482 return txq;
483 }
484
485 static inline bool tun_not_capable(struct tun_struct *tun)
486 {
487 const struct cred *cred = current_cred();
488 struct net *net = dev_net(tun->dev);
489
490 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
491 (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
492 !ns_capable(net->user_ns, CAP_NET_ADMIN);
493 }
494
495 static void tun_set_real_num_queues(struct tun_struct *tun)
496 {
497 netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
498 netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
499 }
500
501 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
502 {
503 tfile->detached = tun;
504 list_add_tail(&tfile->next, &tun->disabled);
505 ++tun->numdisabled;
506 }
507
508 static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
509 {
510 struct tun_struct *tun = tfile->detached;
511
512 tfile->detached = NULL;
513 list_del_init(&tfile->next);
514 --tun->numdisabled;
515 return tun;
516 }
517
518 static void tun_queue_purge(struct tun_file *tfile)
519 {
520 struct sk_buff *skb;
521
522 while ((skb = skb_array_consume(&tfile->tx_array)) != NULL)
523 kfree_skb(skb);
524
525 skb_queue_purge(&tfile->sk.sk_error_queue);
526 }
527
528 static void __tun_detach(struct tun_file *tfile, bool clean)
529 {
530 struct tun_file *ntfile;
531 struct tun_struct *tun;
532
533 tun = rtnl_dereference(tfile->tun);
534
535 if (tun && !tfile->detached) {
536 u16 index = tfile->queue_index;
537 BUG_ON(index >= tun->numqueues);
538
539 rcu_assign_pointer(tun->tfiles[index],
540 tun->tfiles[tun->numqueues - 1]);
541 ntfile = rtnl_dereference(tun->tfiles[index]);
542 ntfile->queue_index = index;
543
544 --tun->numqueues;
545 if (clean) {
546 RCU_INIT_POINTER(tfile->tun, NULL);
547 sock_put(&tfile->sk);
548 } else
549 tun_disable_queue(tun, tfile);
550
551 synchronize_net();
552 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
553 /* Drop read queue */
554 tun_queue_purge(tfile);
555 tun_set_real_num_queues(tun);
556 } else if (tfile->detached && clean) {
557 tun = tun_enable_queue(tfile);
558 sock_put(&tfile->sk);
559 }
560
561 if (clean) {
562 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
563 netif_carrier_off(tun->dev);
564
565 if (!(tun->flags & IFF_PERSIST) &&
566 tun->dev->reg_state == NETREG_REGISTERED)
567 unregister_netdevice(tun->dev);
568 }
569 if (tun)
570 skb_array_cleanup(&tfile->tx_array);
571 sock_put(&tfile->sk);
572 }
573 }
574
575 static void tun_detach(struct tun_file *tfile, bool clean)
576 {
577 rtnl_lock();
578 __tun_detach(tfile, clean);
579 rtnl_unlock();
580 }
581
582 static void tun_detach_all(struct net_device *dev)
583 {
584 struct tun_struct *tun = netdev_priv(dev);
585 struct tun_file *tfile, *tmp;
586 int i, n = tun->numqueues;
587
588 for (i = 0; i < n; i++) {
589 tfile = rtnl_dereference(tun->tfiles[i]);
590 BUG_ON(!tfile);
591 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
592 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
593 RCU_INIT_POINTER(tfile->tun, NULL);
594 --tun->numqueues;
595 }
596 list_for_each_entry(tfile, &tun->disabled, next) {
597 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
598 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
599 RCU_INIT_POINTER(tfile->tun, NULL);
600 }
601 BUG_ON(tun->numqueues != 0);
602
603 synchronize_net();
604 for (i = 0; i < n; i++) {
605 tfile = rtnl_dereference(tun->tfiles[i]);
606 /* Drop read queue */
607 tun_queue_purge(tfile);
608 sock_put(&tfile->sk);
609 }
610 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
611 tun_enable_queue(tfile);
612 tun_queue_purge(tfile);
613 sock_put(&tfile->sk);
614 }
615 BUG_ON(tun->numdisabled != 0);
616
617 if (tun->flags & IFF_PERSIST)
618 module_put(THIS_MODULE);
619 }
620
621 static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter)
622 {
623 struct tun_file *tfile = file->private_data;
624 struct net_device *dev = tun->dev;
625 int err;
626
627 err = security_tun_dev_attach(tfile->socket.sk, tun->security);
628 if (err < 0)
629 goto out;
630
631 err = -EINVAL;
632 if (rtnl_dereference(tfile->tun) && !tfile->detached)
633 goto out;
634
635 err = -EBUSY;
636 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
637 goto out;
638
639 err = -E2BIG;
640 if (!tfile->detached &&
641 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
642 goto out;
643
644 err = 0;
645
646 /* Re-attach the filter to persist device */
647 if (!skip_filter && (tun->filter_attached == true)) {
648 lock_sock(tfile->socket.sk);
649 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
650 release_sock(tfile->socket.sk);
651 if (!err)
652 goto out;
653 }
654
655 if (!tfile->detached &&
656 skb_array_init(&tfile->tx_array, dev->tx_queue_len, GFP_KERNEL)) {
657 err = -ENOMEM;
658 goto out;
659 }
660
661 tfile->queue_index = tun->numqueues;
662 tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
663 rcu_assign_pointer(tfile->tun, tun);
664 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
665 tun->numqueues++;
666
667 if (tfile->detached)
668 tun_enable_queue(tfile);
669 else
670 sock_hold(&tfile->sk);
671
672 tun_set_real_num_queues(tun);
673
674 /* device is allowed to go away first, so no need to hold extra
675 * refcnt.
676 */
677
678 out:
679 return err;
680 }
681
682 static struct tun_struct *__tun_get(struct tun_file *tfile)
683 {
684 struct tun_struct *tun;
685
686 rcu_read_lock();
687 tun = rcu_dereference(tfile->tun);
688 if (tun)
689 dev_hold(tun->dev);
690 rcu_read_unlock();
691
692 return tun;
693 }
694
695 static struct tun_struct *tun_get(struct file *file)
696 {
697 return __tun_get(file->private_data);
698 }
699
700 static void tun_put(struct tun_struct *tun)
701 {
702 dev_put(tun->dev);
703 }
704
705 /* TAP filtering */
706 static void addr_hash_set(u32 *mask, const u8 *addr)
707 {
708 int n = ether_crc(ETH_ALEN, addr) >> 26;
709 mask[n >> 5] |= (1 << (n & 31));
710 }
711
712 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
713 {
714 int n = ether_crc(ETH_ALEN, addr) >> 26;
715 return mask[n >> 5] & (1 << (n & 31));
716 }
717
718 static int update_filter(struct tap_filter *filter, void __user *arg)
719 {
720 struct { u8 u[ETH_ALEN]; } *addr;
721 struct tun_filter uf;
722 int err, alen, n, nexact;
723
724 if (copy_from_user(&uf, arg, sizeof(uf)))
725 return -EFAULT;
726
727 if (!uf.count) {
728 /* Disabled */
729 filter->count = 0;
730 return 0;
731 }
732
733 alen = ETH_ALEN * uf.count;
734 addr = memdup_user(arg + sizeof(uf), alen);
735 if (IS_ERR(addr))
736 return PTR_ERR(addr);
737
738 /* The filter is updated without holding any locks. Which is
739 * perfectly safe. We disable it first and in the worst
740 * case we'll accept a few undesired packets. */
741 filter->count = 0;
742 wmb();
743
744 /* Use first set of addresses as an exact filter */
745 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
746 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
747
748 nexact = n;
749
750 /* Remaining multicast addresses are hashed,
751 * unicast will leave the filter disabled. */
752 memset(filter->mask, 0, sizeof(filter->mask));
753 for (; n < uf.count; n++) {
754 if (!is_multicast_ether_addr(addr[n].u)) {
755 err = 0; /* no filter */
756 goto free_addr;
757 }
758 addr_hash_set(filter->mask, addr[n].u);
759 }
760
761 /* For ALLMULTI just set the mask to all ones.
762 * This overrides the mask populated above. */
763 if ((uf.flags & TUN_FLT_ALLMULTI))
764 memset(filter->mask, ~0, sizeof(filter->mask));
765
766 /* Now enable the filter */
767 wmb();
768 filter->count = nexact;
769
770 /* Return the number of exact filters */
771 err = nexact;
772 free_addr:
773 kfree(addr);
774 return err;
775 }
776
777 /* Returns: 0 - drop, !=0 - accept */
778 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
779 {
780 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
781 * at this point. */
782 struct ethhdr *eh = (struct ethhdr *) skb->data;
783 int i;
784
785 /* Exact match */
786 for (i = 0; i < filter->count; i++)
787 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
788 return 1;
789
790 /* Inexact match (multicast only) */
791 if (is_multicast_ether_addr(eh->h_dest))
792 return addr_hash_test(filter->mask, eh->h_dest);
793
794 return 0;
795 }
796
797 /*
798 * Checks whether the packet is accepted or not.
799 * Returns: 0 - drop, !=0 - accept
800 */
801 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
802 {
803 if (!filter->count)
804 return 1;
805
806 return run_filter(filter, skb);
807 }
808
809 /* Network device part of the driver */
810
811 static const struct ethtool_ops tun_ethtool_ops;
812
813 /* Net device detach from fd. */
814 static void tun_net_uninit(struct net_device *dev)
815 {
816 tun_detach_all(dev);
817 }
818
819 /* Net device open. */
820 static int tun_net_open(struct net_device *dev)
821 {
822 netif_tx_start_all_queues(dev);
823 return 0;
824 }
825
826 /* Net device close. */
827 static int tun_net_close(struct net_device *dev)
828 {
829 netif_tx_stop_all_queues(dev);
830 return 0;
831 }
832
833 /* Net device start xmit */
834 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
835 {
836 struct tun_struct *tun = netdev_priv(dev);
837 int txq = skb->queue_mapping;
838 struct tun_file *tfile;
839 u32 numqueues = 0;
840
841 rcu_read_lock();
842 tfile = rcu_dereference(tun->tfiles[txq]);
843 numqueues = ACCESS_ONCE(tun->numqueues);
844
845 /* Drop packet if interface is not attached */
846 if (txq >= numqueues)
847 goto drop;
848
849 #ifdef CONFIG_RPS
850 if (numqueues == 1 && static_key_false(&rps_needed)) {
851 /* Select queue was not called for the skbuff, so we extract the
852 * RPS hash and save it into the flow_table here.
853 */
854 __u32 rxhash;
855
856 rxhash = skb_get_hash(skb);
857 if (rxhash) {
858 struct tun_flow_entry *e;
859 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)],
860 rxhash);
861 if (e)
862 tun_flow_save_rps_rxhash(e, rxhash);
863 }
864 }
865 #endif
866
867 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
868
869 BUG_ON(!tfile);
870
871 /* Drop if the filter does not like it.
872 * This is a noop if the filter is disabled.
873 * Filter can be enabled only for the TAP devices. */
874 if (!check_filter(&tun->txflt, skb))
875 goto drop;
876
877 if (tfile->socket.sk->sk_filter &&
878 sk_filter(tfile->socket.sk, skb))
879 goto drop;
880
881 /* Limit the number of packets queued by dividing txq length with the
882 * number of queues.
883 */
884 if (skb_queue_len(&tfile->socket.sk->sk_receive_queue) * numqueues
885 >= dev->tx_queue_len)
886 goto drop;
887
888 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
889 goto drop;
890
891 skb_tx_timestamp(skb);
892
893 /* Orphan the skb - required as we might hang on to it
894 * for indefinite time.
895 */
896 skb_orphan(skb);
897
898 nf_reset(skb);
899
900 if (skb_array_produce(&tfile->tx_array, skb))
901 goto drop;
902
903 /* Notify and wake up reader process */
904 if (tfile->flags & TUN_FASYNC)
905 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
906 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
907
908 rcu_read_unlock();
909 return NETDEV_TX_OK;
910
911 drop:
912 this_cpu_inc(tun->pcpu_stats->tx_dropped);
913 skb_tx_error(skb);
914 kfree_skb(skb);
915 rcu_read_unlock();
916 return NET_XMIT_DROP;
917 }
918
919 static void tun_net_mclist(struct net_device *dev)
920 {
921 /*
922 * This callback is supposed to deal with mc filter in
923 * _rx_ path and has nothing to do with the _tx_ path.
924 * In rx path we always accept everything userspace gives us.
925 */
926 }
927
928 #define MIN_MTU 68
929 #define MAX_MTU 65535
930
931 static int
932 tun_net_change_mtu(struct net_device *dev, int new_mtu)
933 {
934 if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
935 return -EINVAL;
936 dev->mtu = new_mtu;
937 return 0;
938 }
939
940 static netdev_features_t tun_net_fix_features(struct net_device *dev,
941 netdev_features_t features)
942 {
943 struct tun_struct *tun = netdev_priv(dev);
944
945 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
946 }
947 #ifdef CONFIG_NET_POLL_CONTROLLER
948 static void tun_poll_controller(struct net_device *dev)
949 {
950 /*
951 * Tun only receives frames when:
952 * 1) the char device endpoint gets data from user space
953 * 2) the tun socket gets a sendmsg call from user space
954 * Since both of those are synchronous operations, we are guaranteed
955 * never to have pending data when we poll for it
956 * so there is nothing to do here but return.
957 * We need this though so netpoll recognizes us as an interface that
958 * supports polling, which enables bridge devices in virt setups to
959 * still use netconsole
960 */
961 return;
962 }
963 #endif
964
965 static void tun_set_headroom(struct net_device *dev, int new_hr)
966 {
967 struct tun_struct *tun = netdev_priv(dev);
968
969 if (new_hr < NET_SKB_PAD)
970 new_hr = NET_SKB_PAD;
971
972 tun->align = new_hr;
973 }
974
975 static struct rtnl_link_stats64 *
976 tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
977 {
978 u32 rx_dropped = 0, tx_dropped = 0, rx_frame_errors = 0;
979 struct tun_struct *tun = netdev_priv(dev);
980 struct tun_pcpu_stats *p;
981 int i;
982
983 for_each_possible_cpu(i) {
984 u64 rxpackets, rxbytes, txpackets, txbytes;
985 unsigned int start;
986
987 p = per_cpu_ptr(tun->pcpu_stats, i);
988 do {
989 start = u64_stats_fetch_begin(&p->syncp);
990 rxpackets = p->rx_packets;
991 rxbytes = p->rx_bytes;
992 txpackets = p->tx_packets;
993 txbytes = p->tx_bytes;
994 } while (u64_stats_fetch_retry(&p->syncp, start));
995
996 stats->rx_packets += rxpackets;
997 stats->rx_bytes += rxbytes;
998 stats->tx_packets += txpackets;
999 stats->tx_bytes += txbytes;
1000
1001 /* u32 counters */
1002 rx_dropped += p->rx_dropped;
1003 rx_frame_errors += p->rx_frame_errors;
1004 tx_dropped += p->tx_dropped;
1005 }
1006 stats->rx_dropped = rx_dropped;
1007 stats->rx_frame_errors = rx_frame_errors;
1008 stats->tx_dropped = tx_dropped;
1009 return stats;
1010 }
1011
1012 static const struct net_device_ops tun_netdev_ops = {
1013 .ndo_uninit = tun_net_uninit,
1014 .ndo_open = tun_net_open,
1015 .ndo_stop = tun_net_close,
1016 .ndo_start_xmit = tun_net_xmit,
1017 .ndo_change_mtu = tun_net_change_mtu,
1018 .ndo_fix_features = tun_net_fix_features,
1019 .ndo_select_queue = tun_select_queue,
1020 #ifdef CONFIG_NET_POLL_CONTROLLER
1021 .ndo_poll_controller = tun_poll_controller,
1022 #endif
1023 .ndo_set_rx_headroom = tun_set_headroom,
1024 .ndo_get_stats64 = tun_net_get_stats64,
1025 };
1026
1027 static const struct net_device_ops tap_netdev_ops = {
1028 .ndo_uninit = tun_net_uninit,
1029 .ndo_open = tun_net_open,
1030 .ndo_stop = tun_net_close,
1031 .ndo_start_xmit = tun_net_xmit,
1032 .ndo_change_mtu = tun_net_change_mtu,
1033 .ndo_fix_features = tun_net_fix_features,
1034 .ndo_set_rx_mode = tun_net_mclist,
1035 .ndo_set_mac_address = eth_mac_addr,
1036 .ndo_validate_addr = eth_validate_addr,
1037 .ndo_select_queue = tun_select_queue,
1038 #ifdef CONFIG_NET_POLL_CONTROLLER
1039 .ndo_poll_controller = tun_poll_controller,
1040 #endif
1041 .ndo_features_check = passthru_features_check,
1042 .ndo_set_rx_headroom = tun_set_headroom,
1043 .ndo_get_stats64 = tun_net_get_stats64,
1044 };
1045
1046 static void tun_flow_init(struct tun_struct *tun)
1047 {
1048 int i;
1049
1050 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1051 INIT_HLIST_HEAD(&tun->flows[i]);
1052
1053 tun->ageing_time = TUN_FLOW_EXPIRE;
1054 setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun);
1055 mod_timer(&tun->flow_gc_timer,
1056 round_jiffies_up(jiffies + tun->ageing_time));
1057 }
1058
1059 static void tun_flow_uninit(struct tun_struct *tun)
1060 {
1061 del_timer_sync(&tun->flow_gc_timer);
1062 tun_flow_flush(tun);
1063 }
1064
1065 /* Initialize net device. */
1066 static void tun_net_init(struct net_device *dev)
1067 {
1068 struct tun_struct *tun = netdev_priv(dev);
1069
1070 switch (tun->flags & TUN_TYPE_MASK) {
1071 case IFF_TUN:
1072 dev->netdev_ops = &tun_netdev_ops;
1073
1074 /* Point-to-Point TUN Device */
1075 dev->hard_header_len = 0;
1076 dev->addr_len = 0;
1077 dev->mtu = 1500;
1078
1079 /* Zero header length */
1080 dev->type = ARPHRD_NONE;
1081 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1082 break;
1083
1084 case IFF_TAP:
1085 dev->netdev_ops = &tap_netdev_ops;
1086 /* Ethernet TAP Device */
1087 ether_setup(dev);
1088 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1089 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1090
1091 eth_hw_addr_random(dev);
1092
1093 break;
1094 }
1095 }
1096
1097 /* Character device part */
1098
1099 /* Poll */
1100 static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
1101 {
1102 struct tun_file *tfile = file->private_data;
1103 struct tun_struct *tun = __tun_get(tfile);
1104 struct sock *sk;
1105 unsigned int mask = 0;
1106
1107 if (!tun)
1108 return POLLERR;
1109
1110 sk = tfile->socket.sk;
1111
1112 tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
1113
1114 poll_wait(file, sk_sleep(sk), wait);
1115
1116 if (!skb_array_empty(&tfile->tx_array))
1117 mask |= POLLIN | POLLRDNORM;
1118
1119 if (sock_writeable(sk) ||
1120 (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1121 sock_writeable(sk)))
1122 mask |= POLLOUT | POLLWRNORM;
1123
1124 if (tun->dev->reg_state != NETREG_REGISTERED)
1125 mask = POLLERR;
1126
1127 tun_put(tun);
1128 return mask;
1129 }
1130
1131 /* prepad is the amount to reserve at front. len is length after that.
1132 * linear is a hint as to how much to copy (usually headers). */
1133 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1134 size_t prepad, size_t len,
1135 size_t linear, int noblock)
1136 {
1137 struct sock *sk = tfile->socket.sk;
1138 struct sk_buff *skb;
1139 int err;
1140
1141 /* Under a page? Don't bother with paged skb. */
1142 if (prepad + len < PAGE_SIZE || !linear)
1143 linear = len;
1144
1145 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1146 &err, 0);
1147 if (!skb)
1148 return ERR_PTR(err);
1149
1150 skb_reserve(skb, prepad);
1151 skb_put(skb, linear);
1152 skb->data_len = len - linear;
1153 skb->len += len - linear;
1154
1155 return skb;
1156 }
1157
1158 /* Get packet from user space buffer */
1159 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1160 void *msg_control, struct iov_iter *from,
1161 int noblock)
1162 {
1163 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1164 struct sk_buff *skb;
1165 size_t total_len = iov_iter_count(from);
1166 size_t len = total_len, align = tun->align, linear;
1167 struct virtio_net_hdr gso = { 0 };
1168 struct tun_pcpu_stats *stats;
1169 int good_linear;
1170 int copylen;
1171 bool zerocopy = false;
1172 int err;
1173 u32 rxhash;
1174 ssize_t n;
1175
1176 if (!(tun->dev->flags & IFF_UP))
1177 return -EIO;
1178
1179 if (!(tun->flags & IFF_NO_PI)) {
1180 if (len < sizeof(pi))
1181 return -EINVAL;
1182 len -= sizeof(pi);
1183
1184 n = copy_from_iter(&pi, sizeof(pi), from);
1185 if (n != sizeof(pi))
1186 return -EFAULT;
1187 }
1188
1189 if (tun->flags & IFF_VNET_HDR) {
1190 if (len < tun->vnet_hdr_sz)
1191 return -EINVAL;
1192 len -= tun->vnet_hdr_sz;
1193
1194 n = copy_from_iter(&gso, sizeof(gso), from);
1195 if (n != sizeof(gso))
1196 return -EFAULT;
1197
1198 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1199 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1200 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1201
1202 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1203 return -EINVAL;
1204 iov_iter_advance(from, tun->vnet_hdr_sz - sizeof(gso));
1205 }
1206
1207 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1208 align += NET_IP_ALIGN;
1209 if (unlikely(len < ETH_HLEN ||
1210 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1211 return -EINVAL;
1212 }
1213
1214 good_linear = SKB_MAX_HEAD(align);
1215
1216 if (msg_control) {
1217 struct iov_iter i = *from;
1218
1219 /* There are 256 bytes to be copied in skb, so there is
1220 * enough room for skb expand head in case it is used.
1221 * The rest of the buffer is mapped from userspace.
1222 */
1223 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1224 if (copylen > good_linear)
1225 copylen = good_linear;
1226 linear = copylen;
1227 iov_iter_advance(&i, copylen);
1228 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1229 zerocopy = true;
1230 }
1231
1232 if (!zerocopy) {
1233 copylen = len;
1234 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1235 linear = good_linear;
1236 else
1237 linear = tun16_to_cpu(tun, gso.hdr_len);
1238 }
1239
1240 skb = tun_alloc_skb(tfile, align, copylen, linear, noblock);
1241 if (IS_ERR(skb)) {
1242 if (PTR_ERR(skb) != -EAGAIN)
1243 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1244 return PTR_ERR(skb);
1245 }
1246
1247 if (zerocopy)
1248 err = zerocopy_sg_from_iter(skb, from);
1249 else {
1250 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1251 if (!err && msg_control) {
1252 struct ubuf_info *uarg = msg_control;
1253 uarg->callback(uarg, false);
1254 }
1255 }
1256
1257 if (err) {
1258 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1259 kfree_skb(skb);
1260 return -EFAULT;
1261 }
1262
1263 err = virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun));
1264 if (err) {
1265 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
1266 kfree_skb(skb);
1267 return -EINVAL;
1268 }
1269
1270 switch (tun->flags & TUN_TYPE_MASK) {
1271 case IFF_TUN:
1272 if (tun->flags & IFF_NO_PI) {
1273 switch (skb->data[0] & 0xf0) {
1274 case 0x40:
1275 pi.proto = htons(ETH_P_IP);
1276 break;
1277 case 0x60:
1278 pi.proto = htons(ETH_P_IPV6);
1279 break;
1280 default:
1281 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1282 kfree_skb(skb);
1283 return -EINVAL;
1284 }
1285 }
1286
1287 skb_reset_mac_header(skb);
1288 skb->protocol = pi.proto;
1289 skb->dev = tun->dev;
1290 break;
1291 case IFF_TAP:
1292 skb->protocol = eth_type_trans(skb, tun->dev);
1293 break;
1294 }
1295
1296 /* copy skb_ubuf_info for callback when skb has no error */
1297 if (zerocopy) {
1298 skb_shinfo(skb)->destructor_arg = msg_control;
1299 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1300 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1301 }
1302
1303 skb_reset_network_header(skb);
1304 skb_probe_transport_header(skb, 0);
1305
1306 rxhash = skb_get_hash(skb);
1307 netif_rx_ni(skb);
1308
1309 stats = get_cpu_ptr(tun->pcpu_stats);
1310 u64_stats_update_begin(&stats->syncp);
1311 stats->rx_packets++;
1312 stats->rx_bytes += len;
1313 u64_stats_update_end(&stats->syncp);
1314 put_cpu_ptr(stats);
1315
1316 tun_flow_update(tun, rxhash, tfile);
1317 return total_len;
1318 }
1319
1320 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
1321 {
1322 struct file *file = iocb->ki_filp;
1323 struct tun_struct *tun = tun_get(file);
1324 struct tun_file *tfile = file->private_data;
1325 ssize_t result;
1326
1327 if (!tun)
1328 return -EBADFD;
1329
1330 result = tun_get_user(tun, tfile, NULL, from, file->f_flags & O_NONBLOCK);
1331
1332 tun_put(tun);
1333 return result;
1334 }
1335
1336 /* Put packet to the user space buffer */
1337 static ssize_t tun_put_user(struct tun_struct *tun,
1338 struct tun_file *tfile,
1339 struct sk_buff *skb,
1340 struct iov_iter *iter)
1341 {
1342 struct tun_pi pi = { 0, skb->protocol };
1343 struct tun_pcpu_stats *stats;
1344 ssize_t total;
1345 int vlan_offset = 0;
1346 int vlan_hlen = 0;
1347 int vnet_hdr_sz = 0;
1348
1349 if (skb_vlan_tag_present(skb))
1350 vlan_hlen = VLAN_HLEN;
1351
1352 if (tun->flags & IFF_VNET_HDR)
1353 vnet_hdr_sz = tun->vnet_hdr_sz;
1354
1355 total = skb->len + vlan_hlen + vnet_hdr_sz;
1356
1357 if (!(tun->flags & IFF_NO_PI)) {
1358 if (iov_iter_count(iter) < sizeof(pi))
1359 return -EINVAL;
1360
1361 total += sizeof(pi);
1362 if (iov_iter_count(iter) < total) {
1363 /* Packet will be striped */
1364 pi.flags |= TUN_PKT_STRIP;
1365 }
1366
1367 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
1368 return -EFAULT;
1369 }
1370
1371 if (vnet_hdr_sz) {
1372 struct virtio_net_hdr gso = { 0 }; /* no info leak */
1373 int ret;
1374
1375 if (iov_iter_count(iter) < vnet_hdr_sz)
1376 return -EINVAL;
1377
1378 ret = virtio_net_hdr_from_skb(skb, &gso,
1379 tun_is_little_endian(tun));
1380 if (ret) {
1381 struct skb_shared_info *sinfo = skb_shinfo(skb);
1382 pr_err("unexpected GSO type: "
1383 "0x%x, gso_size %d, hdr_len %d\n",
1384 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
1385 tun16_to_cpu(tun, gso.hdr_len));
1386 print_hex_dump(KERN_ERR, "tun: ",
1387 DUMP_PREFIX_NONE,
1388 16, 1, skb->head,
1389 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
1390 WARN_ON_ONCE(1);
1391 return -EINVAL;
1392 }
1393
1394 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
1395 return -EFAULT;
1396
1397 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
1398 }
1399
1400 if (vlan_hlen) {
1401 int ret;
1402 struct {
1403 __be16 h_vlan_proto;
1404 __be16 h_vlan_TCI;
1405 } veth;
1406
1407 veth.h_vlan_proto = skb->vlan_proto;
1408 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
1409
1410 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
1411
1412 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
1413 if (ret || !iov_iter_count(iter))
1414 goto done;
1415
1416 ret = copy_to_iter(&veth, sizeof(veth), iter);
1417 if (ret != sizeof(veth) || !iov_iter_count(iter))
1418 goto done;
1419 }
1420
1421 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
1422
1423 done:
1424 /* caller is in process context, */
1425 stats = get_cpu_ptr(tun->pcpu_stats);
1426 u64_stats_update_begin(&stats->syncp);
1427 stats->tx_packets++;
1428 stats->tx_bytes += skb->len + vlan_hlen;
1429 u64_stats_update_end(&stats->syncp);
1430 put_cpu_ptr(tun->pcpu_stats);
1431
1432 return total;
1433 }
1434
1435 static struct sk_buff *tun_ring_recv(struct tun_file *tfile, int noblock,
1436 int *err)
1437 {
1438 DECLARE_WAITQUEUE(wait, current);
1439 struct sk_buff *skb = NULL;
1440 int error = 0;
1441
1442 skb = skb_array_consume(&tfile->tx_array);
1443 if (skb)
1444 goto out;
1445 if (noblock) {
1446 error = -EAGAIN;
1447 goto out;
1448 }
1449
1450 add_wait_queue(&tfile->wq.wait, &wait);
1451 current->state = TASK_INTERRUPTIBLE;
1452
1453 while (1) {
1454 skb = skb_array_consume(&tfile->tx_array);
1455 if (skb)
1456 break;
1457 if (signal_pending(current)) {
1458 error = -ERESTARTSYS;
1459 break;
1460 }
1461 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
1462 error = -EFAULT;
1463 break;
1464 }
1465
1466 schedule();
1467 }
1468
1469 current->state = TASK_RUNNING;
1470 remove_wait_queue(&tfile->wq.wait, &wait);
1471
1472 out:
1473 *err = error;
1474 return skb;
1475 }
1476
1477 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
1478 struct iov_iter *to,
1479 int noblock)
1480 {
1481 struct sk_buff *skb;
1482 ssize_t ret;
1483 int err;
1484
1485 tun_debug(KERN_INFO, tun, "tun_do_read\n");
1486
1487 if (!iov_iter_count(to))
1488 return 0;
1489
1490 /* Read frames from ring */
1491 skb = tun_ring_recv(tfile, noblock, &err);
1492 if (!skb)
1493 return err;
1494
1495 ret = tun_put_user(tun, tfile, skb, to);
1496 if (unlikely(ret < 0))
1497 kfree_skb(skb);
1498 else
1499 consume_skb(skb);
1500
1501 return ret;
1502 }
1503
1504 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
1505 {
1506 struct file *file = iocb->ki_filp;
1507 struct tun_file *tfile = file->private_data;
1508 struct tun_struct *tun = __tun_get(tfile);
1509 ssize_t len = iov_iter_count(to), ret;
1510
1511 if (!tun)
1512 return -EBADFD;
1513 ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK);
1514 ret = min_t(ssize_t, ret, len);
1515 if (ret > 0)
1516 iocb->ki_pos = ret;
1517 tun_put(tun);
1518 return ret;
1519 }
1520
1521 static void tun_free_netdev(struct net_device *dev)
1522 {
1523 struct tun_struct *tun = netdev_priv(dev);
1524
1525 BUG_ON(!(list_empty(&tun->disabled)));
1526 free_percpu(tun->pcpu_stats);
1527 tun_flow_uninit(tun);
1528 security_tun_dev_free_security(tun->security);
1529 free_netdev(dev);
1530 }
1531
1532 static void tun_setup(struct net_device *dev)
1533 {
1534 struct tun_struct *tun = netdev_priv(dev);
1535
1536 tun->owner = INVALID_UID;
1537 tun->group = INVALID_GID;
1538
1539 dev->ethtool_ops = &tun_ethtool_ops;
1540 dev->destructor = tun_free_netdev;
1541 /* We prefer our own queue length */
1542 dev->tx_queue_len = TUN_READQ_SIZE;
1543 }
1544
1545 /* Trivial set of netlink ops to allow deleting tun or tap
1546 * device with netlink.
1547 */
1548 static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
1549 {
1550 return -EINVAL;
1551 }
1552
1553 static struct rtnl_link_ops tun_link_ops __read_mostly = {
1554 .kind = DRV_NAME,
1555 .priv_size = sizeof(struct tun_struct),
1556 .setup = tun_setup,
1557 .validate = tun_validate,
1558 };
1559
1560 static void tun_sock_write_space(struct sock *sk)
1561 {
1562 struct tun_file *tfile;
1563 wait_queue_head_t *wqueue;
1564
1565 if (!sock_writeable(sk))
1566 return;
1567
1568 if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
1569 return;
1570
1571 wqueue = sk_sleep(sk);
1572 if (wqueue && waitqueue_active(wqueue))
1573 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1574 POLLWRNORM | POLLWRBAND);
1575
1576 tfile = container_of(sk, struct tun_file, sk);
1577 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
1578 }
1579
1580 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
1581 {
1582 int ret;
1583 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1584 struct tun_struct *tun = __tun_get(tfile);
1585
1586 if (!tun)
1587 return -EBADFD;
1588
1589 ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter,
1590 m->msg_flags & MSG_DONTWAIT);
1591 tun_put(tun);
1592 return ret;
1593 }
1594
1595 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
1596 int flags)
1597 {
1598 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1599 struct tun_struct *tun = __tun_get(tfile);
1600 int ret;
1601
1602 if (!tun)
1603 return -EBADFD;
1604
1605 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
1606 ret = -EINVAL;
1607 goto out;
1608 }
1609 if (flags & MSG_ERRQUEUE) {
1610 ret = sock_recv_errqueue(sock->sk, m, total_len,
1611 SOL_PACKET, TUN_TX_TIMESTAMP);
1612 goto out;
1613 }
1614 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT);
1615 if (ret > (ssize_t)total_len) {
1616 m->msg_flags |= MSG_TRUNC;
1617 ret = flags & MSG_TRUNC ? ret : total_len;
1618 }
1619 out:
1620 tun_put(tun);
1621 return ret;
1622 }
1623
1624 static int tun_peek_len(struct socket *sock)
1625 {
1626 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1627 struct tun_struct *tun;
1628 int ret = 0;
1629
1630 tun = __tun_get(tfile);
1631 if (!tun)
1632 return 0;
1633
1634 ret = skb_array_peek_len(&tfile->tx_array);
1635 tun_put(tun);
1636
1637 return ret;
1638 }
1639
1640 /* Ops structure to mimic raw sockets with tun */
1641 static const struct proto_ops tun_socket_ops = {
1642 .peek_len = tun_peek_len,
1643 .sendmsg = tun_sendmsg,
1644 .recvmsg = tun_recvmsg,
1645 };
1646
1647 static struct proto tun_proto = {
1648 .name = "tun",
1649 .owner = THIS_MODULE,
1650 .obj_size = sizeof(struct tun_file),
1651 };
1652
1653 static int tun_flags(struct tun_struct *tun)
1654 {
1655 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
1656 }
1657
1658 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1659 char *buf)
1660 {
1661 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1662 return sprintf(buf, "0x%x\n", tun_flags(tun));
1663 }
1664
1665 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1666 char *buf)
1667 {
1668 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1669 return uid_valid(tun->owner)?
1670 sprintf(buf, "%u\n",
1671 from_kuid_munged(current_user_ns(), tun->owner)):
1672 sprintf(buf, "-1\n");
1673 }
1674
1675 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1676 char *buf)
1677 {
1678 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1679 return gid_valid(tun->group) ?
1680 sprintf(buf, "%u\n",
1681 from_kgid_munged(current_user_ns(), tun->group)):
1682 sprintf(buf, "-1\n");
1683 }
1684
1685 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1686 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1687 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1688
1689 static struct attribute *tun_dev_attrs[] = {
1690 &dev_attr_tun_flags.attr,
1691 &dev_attr_owner.attr,
1692 &dev_attr_group.attr,
1693 NULL
1694 };
1695
1696 static const struct attribute_group tun_attr_group = {
1697 .attrs = tun_dev_attrs
1698 };
1699
1700 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1701 {
1702 struct tun_struct *tun;
1703 struct tun_file *tfile = file->private_data;
1704 struct net_device *dev;
1705 int err;
1706
1707 if (tfile->detached)
1708 return -EINVAL;
1709
1710 dev = __dev_get_by_name(net, ifr->ifr_name);
1711 if (dev) {
1712 if (ifr->ifr_flags & IFF_TUN_EXCL)
1713 return -EBUSY;
1714 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1715 tun = netdev_priv(dev);
1716 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1717 tun = netdev_priv(dev);
1718 else
1719 return -EINVAL;
1720
1721 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
1722 !!(tun->flags & IFF_MULTI_QUEUE))
1723 return -EINVAL;
1724
1725 if (tun_not_capable(tun))
1726 return -EPERM;
1727 err = security_tun_dev_open(tun->security);
1728 if (err < 0)
1729 return err;
1730
1731 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER);
1732 if (err < 0)
1733 return err;
1734
1735 if (tun->flags & IFF_MULTI_QUEUE &&
1736 (tun->numqueues + tun->numdisabled > 1)) {
1737 /* One or more queue has already been attached, no need
1738 * to initialize the device again.
1739 */
1740 return 0;
1741 }
1742 }
1743 else {
1744 char *name;
1745 unsigned long flags = 0;
1746 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
1747 MAX_TAP_QUEUES : 1;
1748
1749 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1750 return -EPERM;
1751 err = security_tun_dev_create();
1752 if (err < 0)
1753 return err;
1754
1755 /* Set dev type */
1756 if (ifr->ifr_flags & IFF_TUN) {
1757 /* TUN device */
1758 flags |= IFF_TUN;
1759 name = "tun%d";
1760 } else if (ifr->ifr_flags & IFF_TAP) {
1761 /* TAP device */
1762 flags |= IFF_TAP;
1763 name = "tap%d";
1764 } else
1765 return -EINVAL;
1766
1767 if (*ifr->ifr_name)
1768 name = ifr->ifr_name;
1769
1770 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
1771 NET_NAME_UNKNOWN, tun_setup, queues,
1772 queues);
1773
1774 if (!dev)
1775 return -ENOMEM;
1776
1777 dev_net_set(dev, net);
1778 dev->rtnl_link_ops = &tun_link_ops;
1779 dev->ifindex = tfile->ifindex;
1780 dev->sysfs_groups[0] = &tun_attr_group;
1781
1782 tun = netdev_priv(dev);
1783 tun->dev = dev;
1784 tun->flags = flags;
1785 tun->txflt.count = 0;
1786 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1787
1788 tun->align = NET_SKB_PAD;
1789 tun->filter_attached = false;
1790 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
1791
1792 tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats);
1793 if (!tun->pcpu_stats) {
1794 err = -ENOMEM;
1795 goto err_free_dev;
1796 }
1797
1798 spin_lock_init(&tun->lock);
1799
1800 err = security_tun_dev_alloc_security(&tun->security);
1801 if (err < 0)
1802 goto err_free_stat;
1803
1804 tun_net_init(dev);
1805 tun_flow_init(tun);
1806
1807 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1808 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
1809 NETIF_F_HW_VLAN_STAG_TX;
1810 dev->features = dev->hw_features | NETIF_F_LLTX;
1811 dev->vlan_features = dev->features &
1812 ~(NETIF_F_HW_VLAN_CTAG_TX |
1813 NETIF_F_HW_VLAN_STAG_TX);
1814
1815 INIT_LIST_HEAD(&tun->disabled);
1816 err = tun_attach(tun, file, false);
1817 if (err < 0)
1818 goto err_free_flow;
1819
1820 err = register_netdevice(tun->dev);
1821 if (err < 0)
1822 goto err_detach;
1823 }
1824
1825 netif_carrier_on(tun->dev);
1826
1827 tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1828
1829 tun->flags = (tun->flags & ~TUN_FEATURES) |
1830 (ifr->ifr_flags & TUN_FEATURES);
1831
1832 /* Make sure persistent devices do not get stuck in
1833 * xoff state.
1834 */
1835 if (netif_running(tun->dev))
1836 netif_tx_wake_all_queues(tun->dev);
1837
1838 strcpy(ifr->ifr_name, tun->dev->name);
1839 return 0;
1840
1841 err_detach:
1842 tun_detach_all(dev);
1843 err_free_flow:
1844 tun_flow_uninit(tun);
1845 security_tun_dev_free_security(tun->security);
1846 err_free_stat:
1847 free_percpu(tun->pcpu_stats);
1848 err_free_dev:
1849 free_netdev(dev);
1850 return err;
1851 }
1852
1853 static void tun_get_iff(struct net *net, struct tun_struct *tun,
1854 struct ifreq *ifr)
1855 {
1856 tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1857
1858 strcpy(ifr->ifr_name, tun->dev->name);
1859
1860 ifr->ifr_flags = tun_flags(tun);
1861
1862 }
1863
1864 /* This is like a cut-down ethtool ops, except done via tun fd so no
1865 * privs required. */
1866 static int set_offload(struct tun_struct *tun, unsigned long arg)
1867 {
1868 netdev_features_t features = 0;
1869
1870 if (arg & TUN_F_CSUM) {
1871 features |= NETIF_F_HW_CSUM;
1872 arg &= ~TUN_F_CSUM;
1873
1874 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1875 if (arg & TUN_F_TSO_ECN) {
1876 features |= NETIF_F_TSO_ECN;
1877 arg &= ~TUN_F_TSO_ECN;
1878 }
1879 if (arg & TUN_F_TSO4)
1880 features |= NETIF_F_TSO;
1881 if (arg & TUN_F_TSO6)
1882 features |= NETIF_F_TSO6;
1883 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1884 }
1885
1886 if (arg & TUN_F_UFO) {
1887 features |= NETIF_F_UFO;
1888 arg &= ~TUN_F_UFO;
1889 }
1890 }
1891
1892 /* This gives the user a way to test for new features in future by
1893 * trying to set them. */
1894 if (arg)
1895 return -EINVAL;
1896
1897 tun->set_features = features;
1898 netdev_update_features(tun->dev);
1899
1900 return 0;
1901 }
1902
1903 static void tun_detach_filter(struct tun_struct *tun, int n)
1904 {
1905 int i;
1906 struct tun_file *tfile;
1907
1908 for (i = 0; i < n; i++) {
1909 tfile = rtnl_dereference(tun->tfiles[i]);
1910 lock_sock(tfile->socket.sk);
1911 sk_detach_filter(tfile->socket.sk);
1912 release_sock(tfile->socket.sk);
1913 }
1914
1915 tun->filter_attached = false;
1916 }
1917
1918 static int tun_attach_filter(struct tun_struct *tun)
1919 {
1920 int i, ret = 0;
1921 struct tun_file *tfile;
1922
1923 for (i = 0; i < tun->numqueues; i++) {
1924 tfile = rtnl_dereference(tun->tfiles[i]);
1925 lock_sock(tfile->socket.sk);
1926 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
1927 release_sock(tfile->socket.sk);
1928 if (ret) {
1929 tun_detach_filter(tun, i);
1930 return ret;
1931 }
1932 }
1933
1934 tun->filter_attached = true;
1935 return ret;
1936 }
1937
1938 static void tun_set_sndbuf(struct tun_struct *tun)
1939 {
1940 struct tun_file *tfile;
1941 int i;
1942
1943 for (i = 0; i < tun->numqueues; i++) {
1944 tfile = rtnl_dereference(tun->tfiles[i]);
1945 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
1946 }
1947 }
1948
1949 static int tun_set_queue(struct file *file, struct ifreq *ifr)
1950 {
1951 struct tun_file *tfile = file->private_data;
1952 struct tun_struct *tun;
1953 int ret = 0;
1954
1955 rtnl_lock();
1956
1957 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
1958 tun = tfile->detached;
1959 if (!tun) {
1960 ret = -EINVAL;
1961 goto unlock;
1962 }
1963 ret = security_tun_dev_attach_queue(tun->security);
1964 if (ret < 0)
1965 goto unlock;
1966 ret = tun_attach(tun, file, false);
1967 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
1968 tun = rtnl_dereference(tfile->tun);
1969 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
1970 ret = -EINVAL;
1971 else
1972 __tun_detach(tfile, false);
1973 } else
1974 ret = -EINVAL;
1975
1976 unlock:
1977 rtnl_unlock();
1978 return ret;
1979 }
1980
1981 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1982 unsigned long arg, int ifreq_len)
1983 {
1984 struct tun_file *tfile = file->private_data;
1985 struct tun_struct *tun;
1986 void __user* argp = (void __user*)arg;
1987 struct ifreq ifr;
1988 kuid_t owner;
1989 kgid_t group;
1990 int sndbuf;
1991 int vnet_hdr_sz;
1992 unsigned int ifindex;
1993 int le;
1994 int ret;
1995
1996 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) {
1997 if (copy_from_user(&ifr, argp, ifreq_len))
1998 return -EFAULT;
1999 } else {
2000 memset(&ifr, 0, sizeof(ifr));
2001 }
2002 if (cmd == TUNGETFEATURES) {
2003 /* Currently this just means: "what IFF flags are valid?".
2004 * This is needed because we never checked for invalid flags on
2005 * TUNSETIFF.
2006 */
2007 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
2008 (unsigned int __user*)argp);
2009 } else if (cmd == TUNSETQUEUE)
2010 return tun_set_queue(file, &ifr);
2011
2012 ret = 0;
2013 rtnl_lock();
2014
2015 tun = __tun_get(tfile);
2016 if (cmd == TUNSETIFF && !tun) {
2017 ifr.ifr_name[IFNAMSIZ-1] = '\0';
2018
2019 ret = tun_set_iff(sock_net(&tfile->sk), file, &ifr);
2020
2021 if (ret)
2022 goto unlock;
2023
2024 if (copy_to_user(argp, &ifr, ifreq_len))
2025 ret = -EFAULT;
2026 goto unlock;
2027 }
2028 if (cmd == TUNSETIFINDEX) {
2029 ret = -EPERM;
2030 if (tun)
2031 goto unlock;
2032
2033 ret = -EFAULT;
2034 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
2035 goto unlock;
2036
2037 ret = 0;
2038 tfile->ifindex = ifindex;
2039 goto unlock;
2040 }
2041
2042 ret = -EBADFD;
2043 if (!tun)
2044 goto unlock;
2045
2046 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
2047
2048 ret = 0;
2049 switch (cmd) {
2050 case TUNGETIFF:
2051 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2052
2053 if (tfile->detached)
2054 ifr.ifr_flags |= IFF_DETACH_QUEUE;
2055 if (!tfile->socket.sk->sk_filter)
2056 ifr.ifr_flags |= IFF_NOFILTER;
2057
2058 if (copy_to_user(argp, &ifr, ifreq_len))
2059 ret = -EFAULT;
2060 break;
2061
2062 case TUNSETNOCSUM:
2063 /* Disable/Enable checksum */
2064
2065 /* [unimplemented] */
2066 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
2067 arg ? "disabled" : "enabled");
2068 break;
2069
2070 case TUNSETPERSIST:
2071 /* Disable/Enable persist mode. Keep an extra reference to the
2072 * module to prevent the module being unprobed.
2073 */
2074 if (arg && !(tun->flags & IFF_PERSIST)) {
2075 tun->flags |= IFF_PERSIST;
2076 __module_get(THIS_MODULE);
2077 }
2078 if (!arg && (tun->flags & IFF_PERSIST)) {
2079 tun->flags &= ~IFF_PERSIST;
2080 module_put(THIS_MODULE);
2081 }
2082
2083 tun_debug(KERN_INFO, tun, "persist %s\n",
2084 arg ? "enabled" : "disabled");
2085 break;
2086
2087 case TUNSETOWNER:
2088 /* Set owner of the device */
2089 owner = make_kuid(current_user_ns(), arg);
2090 if (!uid_valid(owner)) {
2091 ret = -EINVAL;
2092 break;
2093 }
2094 tun->owner = owner;
2095 tun_debug(KERN_INFO, tun, "owner set to %u\n",
2096 from_kuid(&init_user_ns, tun->owner));
2097 break;
2098
2099 case TUNSETGROUP:
2100 /* Set group of the device */
2101 group = make_kgid(current_user_ns(), arg);
2102 if (!gid_valid(group)) {
2103 ret = -EINVAL;
2104 break;
2105 }
2106 tun->group = group;
2107 tun_debug(KERN_INFO, tun, "group set to %u\n",
2108 from_kgid(&init_user_ns, tun->group));
2109 break;
2110
2111 case TUNSETLINK:
2112 /* Only allow setting the type when the interface is down */
2113 if (tun->dev->flags & IFF_UP) {
2114 tun_debug(KERN_INFO, tun,
2115 "Linktype set failed because interface is up\n");
2116 ret = -EBUSY;
2117 } else {
2118 tun->dev->type = (int) arg;
2119 tun_debug(KERN_INFO, tun, "linktype set to %d\n",
2120 tun->dev->type);
2121 ret = 0;
2122 }
2123 break;
2124
2125 #ifdef TUN_DEBUG
2126 case TUNSETDEBUG:
2127 tun->debug = arg;
2128 break;
2129 #endif
2130 case TUNSETOFFLOAD:
2131 ret = set_offload(tun, arg);
2132 break;
2133
2134 case TUNSETTXFILTER:
2135 /* Can be set only for TAPs */
2136 ret = -EINVAL;
2137 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2138 break;
2139 ret = update_filter(&tun->txflt, (void __user *)arg);
2140 break;
2141
2142 case SIOCGIFHWADDR:
2143 /* Get hw address */
2144 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
2145 ifr.ifr_hwaddr.sa_family = tun->dev->type;
2146 if (copy_to_user(argp, &ifr, ifreq_len))
2147 ret = -EFAULT;
2148 break;
2149
2150 case SIOCSIFHWADDR:
2151 /* Set hw address */
2152 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
2153 ifr.ifr_hwaddr.sa_data);
2154
2155 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
2156 break;
2157
2158 case TUNGETSNDBUF:
2159 sndbuf = tfile->socket.sk->sk_sndbuf;
2160 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
2161 ret = -EFAULT;
2162 break;
2163
2164 case TUNSETSNDBUF:
2165 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
2166 ret = -EFAULT;
2167 break;
2168 }
2169
2170 tun->sndbuf = sndbuf;
2171 tun_set_sndbuf(tun);
2172 break;
2173
2174 case TUNGETVNETHDRSZ:
2175 vnet_hdr_sz = tun->vnet_hdr_sz;
2176 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
2177 ret = -EFAULT;
2178 break;
2179
2180 case TUNSETVNETHDRSZ:
2181 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
2182 ret = -EFAULT;
2183 break;
2184 }
2185 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
2186 ret = -EINVAL;
2187 break;
2188 }
2189
2190 tun->vnet_hdr_sz = vnet_hdr_sz;
2191 break;
2192
2193 case TUNGETVNETLE:
2194 le = !!(tun->flags & TUN_VNET_LE);
2195 if (put_user(le, (int __user *)argp))
2196 ret = -EFAULT;
2197 break;
2198
2199 case TUNSETVNETLE:
2200 if (get_user(le, (int __user *)argp)) {
2201 ret = -EFAULT;
2202 break;
2203 }
2204 if (le)
2205 tun->flags |= TUN_VNET_LE;
2206 else
2207 tun->flags &= ~TUN_VNET_LE;
2208 break;
2209
2210 case TUNGETVNETBE:
2211 ret = tun_get_vnet_be(tun, argp);
2212 break;
2213
2214 case TUNSETVNETBE:
2215 ret = tun_set_vnet_be(tun, argp);
2216 break;
2217
2218 case TUNATTACHFILTER:
2219 /* Can be set only for TAPs */
2220 ret = -EINVAL;
2221 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2222 break;
2223 ret = -EFAULT;
2224 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
2225 break;
2226
2227 ret = tun_attach_filter(tun);
2228 break;
2229
2230 case TUNDETACHFILTER:
2231 /* Can be set only for TAPs */
2232 ret = -EINVAL;
2233 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2234 break;
2235 ret = 0;
2236 tun_detach_filter(tun, tun->numqueues);
2237 break;
2238
2239 case TUNGETFILTER:
2240 ret = -EINVAL;
2241 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2242 break;
2243 ret = -EFAULT;
2244 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
2245 break;
2246 ret = 0;
2247 break;
2248
2249 default:
2250 ret = -EINVAL;
2251 break;
2252 }
2253
2254 unlock:
2255 rtnl_unlock();
2256 if (tun)
2257 tun_put(tun);
2258 return ret;
2259 }
2260
2261 static long tun_chr_ioctl(struct file *file,
2262 unsigned int cmd, unsigned long arg)
2263 {
2264 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
2265 }
2266
2267 #ifdef CONFIG_COMPAT
2268 static long tun_chr_compat_ioctl(struct file *file,
2269 unsigned int cmd, unsigned long arg)
2270 {
2271 switch (cmd) {
2272 case TUNSETIFF:
2273 case TUNGETIFF:
2274 case TUNSETTXFILTER:
2275 case TUNGETSNDBUF:
2276 case TUNSETSNDBUF:
2277 case SIOCGIFHWADDR:
2278 case SIOCSIFHWADDR:
2279 arg = (unsigned long)compat_ptr(arg);
2280 break;
2281 default:
2282 arg = (compat_ulong_t)arg;
2283 break;
2284 }
2285
2286 /*
2287 * compat_ifreq is shorter than ifreq, so we must not access beyond
2288 * the end of that structure. All fields that are used in this
2289 * driver are compatible though, we don't need to convert the
2290 * contents.
2291 */
2292 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
2293 }
2294 #endif /* CONFIG_COMPAT */
2295
2296 static int tun_chr_fasync(int fd, struct file *file, int on)
2297 {
2298 struct tun_file *tfile = file->private_data;
2299 int ret;
2300
2301 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
2302 goto out;
2303
2304 if (on) {
2305 __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
2306 tfile->flags |= TUN_FASYNC;
2307 } else
2308 tfile->flags &= ~TUN_FASYNC;
2309 ret = 0;
2310 out:
2311 return ret;
2312 }
2313
2314 static int tun_chr_open(struct inode *inode, struct file * file)
2315 {
2316 struct net *net = current->nsproxy->net_ns;
2317 struct tun_file *tfile;
2318
2319 DBG1(KERN_INFO, "tunX: tun_chr_open\n");
2320
2321 tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
2322 &tun_proto, 0);
2323 if (!tfile)
2324 return -ENOMEM;
2325 RCU_INIT_POINTER(tfile->tun, NULL);
2326 tfile->flags = 0;
2327 tfile->ifindex = 0;
2328
2329 init_waitqueue_head(&tfile->wq.wait);
2330 RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq);
2331
2332 tfile->socket.file = file;
2333 tfile->socket.ops = &tun_socket_ops;
2334
2335 sock_init_data(&tfile->socket, &tfile->sk);
2336
2337 tfile->sk.sk_write_space = tun_sock_write_space;
2338 tfile->sk.sk_sndbuf = INT_MAX;
2339
2340 file->private_data = tfile;
2341 INIT_LIST_HEAD(&tfile->next);
2342
2343 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
2344
2345 return 0;
2346 }
2347
2348 static int tun_chr_close(struct inode *inode, struct file *file)
2349 {
2350 struct tun_file *tfile = file->private_data;
2351
2352 tun_detach(tfile, true);
2353
2354 return 0;
2355 }
2356
2357 #ifdef CONFIG_PROC_FS
2358 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *f)
2359 {
2360 struct tun_struct *tun;
2361 struct ifreq ifr;
2362
2363 memset(&ifr, 0, sizeof(ifr));
2364
2365 rtnl_lock();
2366 tun = tun_get(f);
2367 if (tun)
2368 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2369 rtnl_unlock();
2370
2371 if (tun)
2372 tun_put(tun);
2373
2374 seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
2375 }
2376 #endif
2377
2378 static const struct file_operations tun_fops = {
2379 .owner = THIS_MODULE,
2380 .llseek = no_llseek,
2381 .read_iter = tun_chr_read_iter,
2382 .write_iter = tun_chr_write_iter,
2383 .poll = tun_chr_poll,
2384 .unlocked_ioctl = tun_chr_ioctl,
2385 #ifdef CONFIG_COMPAT
2386 .compat_ioctl = tun_chr_compat_ioctl,
2387 #endif
2388 .open = tun_chr_open,
2389 .release = tun_chr_close,
2390 .fasync = tun_chr_fasync,
2391 #ifdef CONFIG_PROC_FS
2392 .show_fdinfo = tun_chr_show_fdinfo,
2393 #endif
2394 };
2395
2396 static struct miscdevice tun_miscdev = {
2397 .minor = TUN_MINOR,
2398 .name = "tun",
2399 .nodename = "net/tun",
2400 .fops = &tun_fops,
2401 };
2402
2403 /* ethtool interface */
2404
2405 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
2406 {
2407 cmd->supported = 0;
2408 cmd->advertising = 0;
2409 ethtool_cmd_speed_set(cmd, SPEED_10);
2410 cmd->duplex = DUPLEX_FULL;
2411 cmd->port = PORT_TP;
2412 cmd->phy_address = 0;
2413 cmd->transceiver = XCVR_INTERNAL;
2414 cmd->autoneg = AUTONEG_DISABLE;
2415 cmd->maxtxpkt = 0;
2416 cmd->maxrxpkt = 0;
2417 return 0;
2418 }
2419
2420 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
2421 {
2422 struct tun_struct *tun = netdev_priv(dev);
2423
2424 strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
2425 strlcpy(info->version, DRV_VERSION, sizeof(info->version));
2426
2427 switch (tun->flags & TUN_TYPE_MASK) {
2428 case IFF_TUN:
2429 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
2430 break;
2431 case IFF_TAP:
2432 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
2433 break;
2434 }
2435 }
2436
2437 static u32 tun_get_msglevel(struct net_device *dev)
2438 {
2439 #ifdef TUN_DEBUG
2440 struct tun_struct *tun = netdev_priv(dev);
2441 return tun->debug;
2442 #else
2443 return -EOPNOTSUPP;
2444 #endif
2445 }
2446
2447 static void tun_set_msglevel(struct net_device *dev, u32 value)
2448 {
2449 #ifdef TUN_DEBUG
2450 struct tun_struct *tun = netdev_priv(dev);
2451 tun->debug = value;
2452 #endif
2453 }
2454
2455 static const struct ethtool_ops tun_ethtool_ops = {
2456 .get_settings = tun_get_settings,
2457 .get_drvinfo = tun_get_drvinfo,
2458 .get_msglevel = tun_get_msglevel,
2459 .set_msglevel = tun_set_msglevel,
2460 .get_link = ethtool_op_get_link,
2461 .get_ts_info = ethtool_op_get_ts_info,
2462 };
2463
2464 static int tun_queue_resize(struct tun_struct *tun)
2465 {
2466 struct net_device *dev = tun->dev;
2467 struct tun_file *tfile;
2468 struct skb_array **arrays;
2469 int n = tun->numqueues + tun->numdisabled;
2470 int ret, i;
2471
2472 arrays = kmalloc(sizeof *arrays * n, GFP_KERNEL);
2473 if (!arrays)
2474 return -ENOMEM;
2475
2476 for (i = 0; i < tun->numqueues; i++) {
2477 tfile = rtnl_dereference(tun->tfiles[i]);
2478 arrays[i] = &tfile->tx_array;
2479 }
2480 list_for_each_entry(tfile, &tun->disabled, next)
2481 arrays[i++] = &tfile->tx_array;
2482
2483 ret = skb_array_resize_multiple(arrays, n,
2484 dev->tx_queue_len, GFP_KERNEL);
2485
2486 kfree(arrays);
2487 return ret;
2488 }
2489
2490 static int tun_device_event(struct notifier_block *unused,
2491 unsigned long event, void *ptr)
2492 {
2493 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
2494 struct tun_struct *tun = netdev_priv(dev);
2495
2496 if (dev->rtnl_link_ops != &tun_link_ops)
2497 return NOTIFY_DONE;
2498
2499 switch (event) {
2500 case NETDEV_CHANGE_TX_QUEUE_LEN:
2501 if (tun_queue_resize(tun))
2502 return NOTIFY_BAD;
2503 break;
2504 default:
2505 break;
2506 }
2507
2508 return NOTIFY_DONE;
2509 }
2510
2511 static struct notifier_block tun_notifier_block __read_mostly = {
2512 .notifier_call = tun_device_event,
2513 };
2514
2515 static int __init tun_init(void)
2516 {
2517 int ret = 0;
2518
2519 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
2520 pr_info("%s\n", DRV_COPYRIGHT);
2521
2522 ret = rtnl_link_register(&tun_link_ops);
2523 if (ret) {
2524 pr_err("Can't register link_ops\n");
2525 goto err_linkops;
2526 }
2527
2528 ret = misc_register(&tun_miscdev);
2529 if (ret) {
2530 pr_err("Can't register misc device %d\n", TUN_MINOR);
2531 goto err_misc;
2532 }
2533
2534 register_netdevice_notifier(&tun_notifier_block);
2535 return 0;
2536 err_misc:
2537 rtnl_link_unregister(&tun_link_ops);
2538 err_linkops:
2539 return ret;
2540 }
2541
2542 static void tun_cleanup(void)
2543 {
2544 misc_deregister(&tun_miscdev);
2545 rtnl_link_unregister(&tun_link_ops);
2546 unregister_netdevice_notifier(&tun_notifier_block);
2547 }
2548
2549 /* Get an underlying socket object from tun file. Returns error unless file is
2550 * attached to a device. The returned object works like a packet socket, it
2551 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
2552 * holding a reference to the file for as long as the socket is in use. */
2553 struct socket *tun_get_socket(struct file *file)
2554 {
2555 struct tun_file *tfile;
2556 if (file->f_op != &tun_fops)
2557 return ERR_PTR(-EINVAL);
2558 tfile = file->private_data;
2559 if (!tfile)
2560 return ERR_PTR(-EBADFD);
2561 return &tfile->socket;
2562 }
2563 EXPORT_SYMBOL_GPL(tun_get_socket);
2564
2565 module_init(tun_init);
2566 module_exit(tun_cleanup);
2567 MODULE_DESCRIPTION(DRV_DESCRIPTION);
2568 MODULE_AUTHOR(DRV_COPYRIGHT);
2569 MODULE_LICENSE("GPL");
2570 MODULE_ALIAS_MISCDEV(TUN_MINOR);
2571 MODULE_ALIAS("devname:net/tun");
Linux with added FPC-III support