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tun: fix tun_napi_alloc_frags() frag allocator
[mirror_ubuntu-bionic-kernel.git] / drivers / net / tun.c
1 /*
2 * TUN - Universal TUN/TAP device driver.
3 * Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
16 */
17
18 /*
19 * Changes:
20 *
21 * Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
22 * Add TUNSETLINK ioctl to set the link encapsulation
23 *
24 * Mark Smith <markzzzsmith@yahoo.com.au>
25 * Use eth_random_addr() for tap MAC address.
26 *
27 * Harald Roelle <harald.roelle@ifi.lmu.de> 2004/04/20
28 * Fixes in packet dropping, queue length setting and queue wakeup.
29 * Increased default tx queue length.
30 * Added ethtool API.
31 * Minor cleanups
32 *
33 * Daniel Podlejski <underley@underley.eu.org>
34 * Modifications for 2.3.99-pre5 kernel.
35 */
36
37 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
38
39 #define DRV_NAME "tun"
40 #define DRV_VERSION "1.6"
41 #define DRV_DESCRIPTION "Universal TUN/TAP device driver"
42 #define DRV_COPYRIGHT "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
43
44 #include <linux/module.h>
45 #include <linux/errno.h>
46 #include <linux/kernel.h>
47 #include <linux/sched/signal.h>
48 #include <linux/major.h>
49 #include <linux/slab.h>
50 #include <linux/poll.h>
51 #include <linux/fcntl.h>
52 #include <linux/init.h>
53 #include <linux/skbuff.h>
54 #include <linux/netdevice.h>
55 #include <linux/etherdevice.h>
56 #include <linux/miscdevice.h>
57 #include <linux/ethtool.h>
58 #include <linux/rtnetlink.h>
59 #include <linux/compat.h>
60 #include <linux/if.h>
61 #include <linux/if_arp.h>
62 #include <linux/if_ether.h>
63 #include <linux/if_tun.h>
64 #include <linux/if_vlan.h>
65 #include <linux/crc32.h>
66 #include <linux/nsproxy.h>
67 #include <linux/virtio_net.h>
68 #include <linux/rcupdate.h>
69 #include <net/net_namespace.h>
70 #include <net/netns/generic.h>
71 #include <net/rtnetlink.h>
72 #include <net/sock.h>
73 #include <linux/seq_file.h>
74 #include <linux/uio.h>
75 #include <linux/skb_array.h>
76 #include <linux/bpf.h>
77 #include <linux/bpf_trace.h>
78 #include <linux/mutex.h>
79
80 #include <linux/uaccess.h>
81
82 /* Uncomment to enable debugging */
83 /* #define TUN_DEBUG 1 */
84
85 #ifdef TUN_DEBUG
86 static int debug;
87
88 #define tun_debug(level, tun, fmt, args...) \
89 do { \
90 if (tun->debug) \
91 netdev_printk(level, tun->dev, fmt, ##args); \
92 } while (0)
93 #define DBG1(level, fmt, args...) \
94 do { \
95 if (debug == 2) \
96 printk(level fmt, ##args); \
97 } while (0)
98 #else
99 #define tun_debug(level, tun, fmt, args...) \
100 do { \
101 if (0) \
102 netdev_printk(level, tun->dev, fmt, ##args); \
103 } while (0)
104 #define DBG1(level, fmt, args...) \
105 do { \
106 if (0) \
107 printk(level fmt, ##args); \
108 } while (0)
109 #endif
110
111 #define TUN_HEADROOM 256
112 #define TUN_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
113
114 /* TUN device flags */
115
116 /* IFF_ATTACH_QUEUE is never stored in device flags,
117 * overload it to mean fasync when stored there.
118 */
119 #define TUN_FASYNC IFF_ATTACH_QUEUE
120 /* High bits in flags field are unused. */
121 #define TUN_VNET_LE 0x80000000
122 #define TUN_VNET_BE 0x40000000
123
124 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
125 IFF_MULTI_QUEUE | IFF_NAPI | IFF_NAPI_FRAGS)
126
127 #define GOODCOPY_LEN 128
128
129 #define FLT_EXACT_COUNT 8
130 struct tap_filter {
131 unsigned int count; /* Number of addrs. Zero means disabled */
132 u32 mask[2]; /* Mask of the hashed addrs */
133 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
134 };
135
136 /* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
137 * to max number of VCPUs in guest. */
138 #define MAX_TAP_QUEUES 256
139 #define MAX_TAP_FLOWS 4096
140
141 #define TUN_FLOW_EXPIRE (3 * HZ)
142
143 struct tun_pcpu_stats {
144 u64 rx_packets;
145 u64 rx_bytes;
146 u64 tx_packets;
147 u64 tx_bytes;
148 struct u64_stats_sync syncp;
149 u32 rx_dropped;
150 u32 tx_dropped;
151 u32 rx_frame_errors;
152 };
153
154 /* A tun_file connects an open character device to a tuntap netdevice. It
155 * also contains all socket related structures (except sock_fprog and tap_filter)
156 * to serve as one transmit queue for tuntap device. The sock_fprog and
157 * tap_filter were kept in tun_struct since they were used for filtering for the
158 * netdevice not for a specific queue (at least I didn't see the requirement for
159 * this).
160 *
161 * RCU usage:
162 * The tun_file and tun_struct are loosely coupled, the pointer from one to the
163 * other can only be read while rcu_read_lock or rtnl_lock is held.
164 */
165 struct tun_file {
166 struct sock sk;
167 struct socket socket;
168 struct socket_wq wq;
169 struct tun_struct __rcu *tun;
170 struct fasync_struct *fasync;
171 /* only used for fasnyc */
172 unsigned int flags;
173 union {
174 u16 queue_index;
175 unsigned int ifindex;
176 };
177 struct napi_struct napi;
178 bool napi_enabled;
179 struct mutex napi_mutex; /* Protects access to the above napi */
180 struct list_head next;
181 struct tun_struct *detached;
182 struct skb_array tx_array;
183 };
184
185 struct tun_flow_entry {
186 struct hlist_node hash_link;
187 struct rcu_head rcu;
188 struct tun_struct *tun;
189
190 u32 rxhash;
191 u32 rps_rxhash;
192 int queue_index;
193 unsigned long updated;
194 };
195
196 #define TUN_NUM_FLOW_ENTRIES 1024
197
198 /* Since the socket were moved to tun_file, to preserve the behavior of persist
199 * device, socket filter, sndbuf and vnet header size were restore when the
200 * file were attached to a persist device.
201 */
202 struct tun_struct {
203 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES];
204 unsigned int numqueues;
205 unsigned int flags;
206 kuid_t owner;
207 kgid_t group;
208
209 struct net_device *dev;
210 netdev_features_t set_features;
211 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
212 NETIF_F_TSO6)
213
214 int align;
215 int vnet_hdr_sz;
216 int sndbuf;
217 struct tap_filter txflt;
218 struct sock_fprog fprog;
219 /* protected by rtnl lock */
220 bool filter_attached;
221 #ifdef TUN_DEBUG
222 int debug;
223 #endif
224 spinlock_t lock;
225 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
226 struct timer_list flow_gc_timer;
227 unsigned long ageing_time;
228 unsigned int numdisabled;
229 struct list_head disabled;
230 void *security;
231 u32 flow_count;
232 u32 rx_batched;
233 struct tun_pcpu_stats __percpu *pcpu_stats;
234 struct bpf_prog __rcu *xdp_prog;
235 };
236
237 static int tun_napi_receive(struct napi_struct *napi, int budget)
238 {
239 struct tun_file *tfile = container_of(napi, struct tun_file, napi);
240 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
241 struct sk_buff_head process_queue;
242 struct sk_buff *skb;
243 int received = 0;
244
245 __skb_queue_head_init(&process_queue);
246
247 spin_lock(&queue->lock);
248 skb_queue_splice_tail_init(queue, &process_queue);
249 spin_unlock(&queue->lock);
250
251 while (received < budget && (skb = __skb_dequeue(&process_queue))) {
252 napi_gro_receive(napi, skb);
253 ++received;
254 }
255
256 if (!skb_queue_empty(&process_queue)) {
257 spin_lock(&queue->lock);
258 skb_queue_splice(&process_queue, queue);
259 spin_unlock(&queue->lock);
260 }
261
262 return received;
263 }
264
265 static int tun_napi_poll(struct napi_struct *napi, int budget)
266 {
267 unsigned int received;
268
269 received = tun_napi_receive(napi, budget);
270
271 if (received < budget)
272 napi_complete_done(napi, received);
273
274 return received;
275 }
276
277 static void tun_napi_init(struct tun_struct *tun, struct tun_file *tfile,
278 bool napi_en)
279 {
280 tfile->napi_enabled = napi_en;
281 if (napi_en) {
282 netif_napi_add(tun->dev, &tfile->napi, tun_napi_poll,
283 NAPI_POLL_WEIGHT);
284 napi_enable(&tfile->napi);
285 mutex_init(&tfile->napi_mutex);
286 }
287 }
288
289 static void tun_napi_disable(struct tun_struct *tun, struct tun_file *tfile)
290 {
291 if (tfile->napi_enabled)
292 napi_disable(&tfile->napi);
293 }
294
295 static void tun_napi_del(struct tun_struct *tun, struct tun_file *tfile)
296 {
297 if (tfile->napi_enabled)
298 netif_napi_del(&tfile->napi);
299 }
300
301 static bool tun_napi_frags_enabled(const struct tun_struct *tun)
302 {
303 return READ_ONCE(tun->flags) & IFF_NAPI_FRAGS;
304 }
305
306 #ifdef CONFIG_TUN_VNET_CROSS_LE
307 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
308 {
309 return tun->flags & TUN_VNET_BE ? false :
310 virtio_legacy_is_little_endian();
311 }
312
313 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
314 {
315 int be = !!(tun->flags & TUN_VNET_BE);
316
317 if (put_user(be, argp))
318 return -EFAULT;
319
320 return 0;
321 }
322
323 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
324 {
325 int be;
326
327 if (get_user(be, argp))
328 return -EFAULT;
329
330 if (be)
331 tun->flags |= TUN_VNET_BE;
332 else
333 tun->flags &= ~TUN_VNET_BE;
334
335 return 0;
336 }
337 #else
338 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
339 {
340 return virtio_legacy_is_little_endian();
341 }
342
343 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
344 {
345 return -EINVAL;
346 }
347
348 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
349 {
350 return -EINVAL;
351 }
352 #endif /* CONFIG_TUN_VNET_CROSS_LE */
353
354 static inline bool tun_is_little_endian(struct tun_struct *tun)
355 {
356 return tun->flags & TUN_VNET_LE ||
357 tun_legacy_is_little_endian(tun);
358 }
359
360 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
361 {
362 return __virtio16_to_cpu(tun_is_little_endian(tun), val);
363 }
364
365 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
366 {
367 return __cpu_to_virtio16(tun_is_little_endian(tun), val);
368 }
369
370 static inline u32 tun_hashfn(u32 rxhash)
371 {
372 return rxhash & 0x3ff;
373 }
374
375 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
376 {
377 struct tun_flow_entry *e;
378
379 hlist_for_each_entry_rcu(e, head, hash_link) {
380 if (e->rxhash == rxhash)
381 return e;
382 }
383 return NULL;
384 }
385
386 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
387 struct hlist_head *head,
388 u32 rxhash, u16 queue_index)
389 {
390 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
391
392 if (e) {
393 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
394 rxhash, queue_index);
395 e->updated = jiffies;
396 e->rxhash = rxhash;
397 e->rps_rxhash = 0;
398 e->queue_index = queue_index;
399 e->tun = tun;
400 hlist_add_head_rcu(&e->hash_link, head);
401 ++tun->flow_count;
402 }
403 return e;
404 }
405
406 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
407 {
408 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
409 e->rxhash, e->queue_index);
410 hlist_del_rcu(&e->hash_link);
411 kfree_rcu(e, rcu);
412 --tun->flow_count;
413 }
414
415 static void tun_flow_flush(struct tun_struct *tun)
416 {
417 int i;
418
419 spin_lock_bh(&tun->lock);
420 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
421 struct tun_flow_entry *e;
422 struct hlist_node *n;
423
424 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
425 tun_flow_delete(tun, e);
426 }
427 spin_unlock_bh(&tun->lock);
428 }
429
430 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
431 {
432 int i;
433
434 spin_lock_bh(&tun->lock);
435 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
436 struct tun_flow_entry *e;
437 struct hlist_node *n;
438
439 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
440 if (e->queue_index == queue_index)
441 tun_flow_delete(tun, e);
442 }
443 }
444 spin_unlock_bh(&tun->lock);
445 }
446
447 static void tun_flow_cleanup(struct timer_list *t)
448 {
449 struct tun_struct *tun = from_timer(tun, t, flow_gc_timer);
450 unsigned long delay = tun->ageing_time;
451 unsigned long next_timer = jiffies + delay;
452 unsigned long count = 0;
453 int i;
454
455 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
456
457 spin_lock(&tun->lock);
458 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
459 struct tun_flow_entry *e;
460 struct hlist_node *n;
461
462 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
463 unsigned long this_timer;
464
465 this_timer = e->updated + delay;
466 if (time_before_eq(this_timer, jiffies)) {
467 tun_flow_delete(tun, e);
468 continue;
469 }
470 count++;
471 if (time_before(this_timer, next_timer))
472 next_timer = this_timer;
473 }
474 }
475
476 if (count)
477 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
478 spin_unlock(&tun->lock);
479 }
480
481 static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
482 struct tun_file *tfile)
483 {
484 struct hlist_head *head;
485 struct tun_flow_entry *e;
486 unsigned long delay = tun->ageing_time;
487 u16 queue_index = tfile->queue_index;
488
489 if (!rxhash)
490 return;
491 else
492 head = &tun->flows[tun_hashfn(rxhash)];
493
494 rcu_read_lock();
495
496 /* We may get a very small possibility of OOO during switching, not
497 * worth to optimize.*/
498 if (tun->numqueues == 1 || tfile->detached)
499 goto unlock;
500
501 e = tun_flow_find(head, rxhash);
502 if (likely(e)) {
503 /* TODO: keep queueing to old queue until it's empty? */
504 e->queue_index = queue_index;
505 e->updated = jiffies;
506 sock_rps_record_flow_hash(e->rps_rxhash);
507 } else {
508 spin_lock_bh(&tun->lock);
509 if (!tun_flow_find(head, rxhash) &&
510 tun->flow_count < MAX_TAP_FLOWS)
511 tun_flow_create(tun, head, rxhash, queue_index);
512
513 if (!timer_pending(&tun->flow_gc_timer))
514 mod_timer(&tun->flow_gc_timer,
515 round_jiffies_up(jiffies + delay));
516 spin_unlock_bh(&tun->lock);
517 }
518
519 unlock:
520 rcu_read_unlock();
521 }
522
523 /**
524 * Save the hash received in the stack receive path and update the
525 * flow_hash table accordingly.
526 */
527 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
528 {
529 if (unlikely(e->rps_rxhash != hash))
530 e->rps_rxhash = hash;
531 }
532
533 /* We try to identify a flow through its rxhash first. The reason that
534 * we do not check rxq no. is because some cards(e.g 82599), chooses
535 * the rxq based on the txq where the last packet of the flow comes. As
536 * the userspace application move between processors, we may get a
537 * different rxq no. here. If we could not get rxhash, then we would
538 * hope the rxq no. may help here.
539 */
540 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
541 void *accel_priv, select_queue_fallback_t fallback)
542 {
543 struct tun_struct *tun = netdev_priv(dev);
544 struct tun_flow_entry *e;
545 u32 txq = 0;
546 u32 numqueues = 0;
547
548 rcu_read_lock();
549 numqueues = READ_ONCE(tun->numqueues);
550
551 txq = __skb_get_hash_symmetric(skb);
552 if (txq) {
553 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
554 if (e) {
555 tun_flow_save_rps_rxhash(e, txq);
556 txq = e->queue_index;
557 } else
558 /* use multiply and shift instead of expensive divide */
559 txq = ((u64)txq * numqueues) >> 32;
560 } else if (likely(skb_rx_queue_recorded(skb))) {
561 txq = skb_get_rx_queue(skb);
562 while (unlikely(txq >= numqueues))
563 txq -= numqueues;
564 }
565
566 rcu_read_unlock();
567 return txq;
568 }
569
570 static inline bool tun_not_capable(struct tun_struct *tun)
571 {
572 const struct cred *cred = current_cred();
573 struct net *net = dev_net(tun->dev);
574
575 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
576 (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
577 !ns_capable(net->user_ns, CAP_NET_ADMIN);
578 }
579
580 static void tun_set_real_num_queues(struct tun_struct *tun)
581 {
582 netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
583 netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
584 }
585
586 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
587 {
588 tfile->detached = tun;
589 list_add_tail(&tfile->next, &tun->disabled);
590 ++tun->numdisabled;
591 }
592
593 static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
594 {
595 struct tun_struct *tun = tfile->detached;
596
597 tfile->detached = NULL;
598 list_del_init(&tfile->next);
599 --tun->numdisabled;
600 return tun;
601 }
602
603 static void tun_queue_purge(struct tun_file *tfile)
604 {
605 struct sk_buff *skb;
606
607 while ((skb = skb_array_consume(&tfile->tx_array)) != NULL)
608 kfree_skb(skb);
609
610 skb_queue_purge(&tfile->sk.sk_write_queue);
611 skb_queue_purge(&tfile->sk.sk_error_queue);
612 }
613
614 static void tun_cleanup_tx_array(struct tun_file *tfile)
615 {
616 if (tfile->tx_array.ring.queue) {
617 skb_array_cleanup(&tfile->tx_array);
618 memset(&tfile->tx_array, 0, sizeof(tfile->tx_array));
619 }
620 }
621
622 static void __tun_detach(struct tun_file *tfile, bool clean)
623 {
624 struct tun_file *ntfile;
625 struct tun_struct *tun;
626
627 tun = rtnl_dereference(tfile->tun);
628
629 if (tun && clean) {
630 tun_napi_disable(tun, tfile);
631 tun_napi_del(tun, tfile);
632 }
633
634 if (tun && !tfile->detached) {
635 u16 index = tfile->queue_index;
636 BUG_ON(index >= tun->numqueues);
637
638 rcu_assign_pointer(tun->tfiles[index],
639 tun->tfiles[tun->numqueues - 1]);
640 ntfile = rtnl_dereference(tun->tfiles[index]);
641 ntfile->queue_index = index;
642
643 --tun->numqueues;
644 if (clean) {
645 RCU_INIT_POINTER(tfile->tun, NULL);
646 sock_put(&tfile->sk);
647 } else
648 tun_disable_queue(tun, tfile);
649
650 synchronize_net();
651 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
652 /* Drop read queue */
653 tun_queue_purge(tfile);
654 tun_set_real_num_queues(tun);
655 } else if (tfile->detached && clean) {
656 tun = tun_enable_queue(tfile);
657 sock_put(&tfile->sk);
658 }
659
660 if (clean) {
661 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
662 netif_carrier_off(tun->dev);
663
664 if (!(tun->flags & IFF_PERSIST) &&
665 tun->dev->reg_state == NETREG_REGISTERED)
666 unregister_netdevice(tun->dev);
667 }
668 tun_cleanup_tx_array(tfile);
669 sock_put(&tfile->sk);
670 }
671 }
672
673 static void tun_detach(struct tun_file *tfile, bool clean)
674 {
675 rtnl_lock();
676 __tun_detach(tfile, clean);
677 rtnl_unlock();
678 }
679
680 static void tun_detach_all(struct net_device *dev)
681 {
682 struct tun_struct *tun = netdev_priv(dev);
683 struct bpf_prog *xdp_prog = rtnl_dereference(tun->xdp_prog);
684 struct tun_file *tfile, *tmp;
685 int i, n = tun->numqueues;
686
687 for (i = 0; i < n; i++) {
688 tfile = rtnl_dereference(tun->tfiles[i]);
689 BUG_ON(!tfile);
690 tun_napi_disable(tun, tfile);
691 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
692 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
693 RCU_INIT_POINTER(tfile->tun, NULL);
694 --tun->numqueues;
695 }
696 list_for_each_entry(tfile, &tun->disabled, next) {
697 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
698 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
699 RCU_INIT_POINTER(tfile->tun, NULL);
700 }
701 BUG_ON(tun->numqueues != 0);
702
703 synchronize_net();
704 for (i = 0; i < n; i++) {
705 tfile = rtnl_dereference(tun->tfiles[i]);
706 tun_napi_del(tun, tfile);
707 /* Drop read queue */
708 tun_queue_purge(tfile);
709 sock_put(&tfile->sk);
710 tun_cleanup_tx_array(tfile);
711 }
712 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
713 tun_enable_queue(tfile);
714 tun_queue_purge(tfile);
715 sock_put(&tfile->sk);
716 tun_cleanup_tx_array(tfile);
717 }
718 BUG_ON(tun->numdisabled != 0);
719
720 if (xdp_prog)
721 bpf_prog_put(xdp_prog);
722
723 if (tun->flags & IFF_PERSIST)
724 module_put(THIS_MODULE);
725 }
726
727 static int tun_attach(struct tun_struct *tun, struct file *file,
728 bool skip_filter, bool napi)
729 {
730 struct tun_file *tfile = file->private_data;
731 struct net_device *dev = tun->dev;
732 int err;
733
734 err = security_tun_dev_attach(tfile->socket.sk, tun->security);
735 if (err < 0)
736 goto out;
737
738 err = -EINVAL;
739 if (rtnl_dereference(tfile->tun) && !tfile->detached)
740 goto out;
741
742 err = -EBUSY;
743 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
744 goto out;
745
746 err = -E2BIG;
747 if (!tfile->detached &&
748 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
749 goto out;
750
751 err = 0;
752
753 /* Re-attach the filter to persist device */
754 if (!skip_filter && (tun->filter_attached == true)) {
755 lock_sock(tfile->socket.sk);
756 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
757 release_sock(tfile->socket.sk);
758 if (!err)
759 goto out;
760 }
761
762 if (!tfile->detached &&
763 skb_array_init(&tfile->tx_array, dev->tx_queue_len, GFP_KERNEL)) {
764 err = -ENOMEM;
765 goto out;
766 }
767
768 tfile->queue_index = tun->numqueues;
769 tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
770 rcu_assign_pointer(tfile->tun, tun);
771 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
772 tun->numqueues++;
773
774 if (tfile->detached) {
775 tun_enable_queue(tfile);
776 } else {
777 sock_hold(&tfile->sk);
778 tun_napi_init(tun, tfile, napi);
779 }
780
781 tun_set_real_num_queues(tun);
782
783 /* device is allowed to go away first, so no need to hold extra
784 * refcnt.
785 */
786
787 out:
788 return err;
789 }
790
791 static struct tun_struct *tun_get(struct tun_file *tfile)
792 {
793 struct tun_struct *tun;
794
795 rcu_read_lock();
796 tun = rcu_dereference(tfile->tun);
797 if (tun)
798 dev_hold(tun->dev);
799 rcu_read_unlock();
800
801 return tun;
802 }
803
804 static void tun_put(struct tun_struct *tun)
805 {
806 dev_put(tun->dev);
807 }
808
809 /* TAP filtering */
810 static void addr_hash_set(u32 *mask, const u8 *addr)
811 {
812 int n = ether_crc(ETH_ALEN, addr) >> 26;
813 mask[n >> 5] |= (1 << (n & 31));
814 }
815
816 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
817 {
818 int n = ether_crc(ETH_ALEN, addr) >> 26;
819 return mask[n >> 5] & (1 << (n & 31));
820 }
821
822 static int update_filter(struct tap_filter *filter, void __user *arg)
823 {
824 struct { u8 u[ETH_ALEN]; } *addr;
825 struct tun_filter uf;
826 int err, alen, n, nexact;
827
828 if (copy_from_user(&uf, arg, sizeof(uf)))
829 return -EFAULT;
830
831 if (!uf.count) {
832 /* Disabled */
833 filter->count = 0;
834 return 0;
835 }
836
837 alen = ETH_ALEN * uf.count;
838 addr = memdup_user(arg + sizeof(uf), alen);
839 if (IS_ERR(addr))
840 return PTR_ERR(addr);
841
842 /* The filter is updated without holding any locks. Which is
843 * perfectly safe. We disable it first and in the worst
844 * case we'll accept a few undesired packets. */
845 filter->count = 0;
846 wmb();
847
848 /* Use first set of addresses as an exact filter */
849 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
850 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
851
852 nexact = n;
853
854 /* Remaining multicast addresses are hashed,
855 * unicast will leave the filter disabled. */
856 memset(filter->mask, 0, sizeof(filter->mask));
857 for (; n < uf.count; n++) {
858 if (!is_multicast_ether_addr(addr[n].u)) {
859 err = 0; /* no filter */
860 goto free_addr;
861 }
862 addr_hash_set(filter->mask, addr[n].u);
863 }
864
865 /* For ALLMULTI just set the mask to all ones.
866 * This overrides the mask populated above. */
867 if ((uf.flags & TUN_FLT_ALLMULTI))
868 memset(filter->mask, ~0, sizeof(filter->mask));
869
870 /* Now enable the filter */
871 wmb();
872 filter->count = nexact;
873
874 /* Return the number of exact filters */
875 err = nexact;
876 free_addr:
877 kfree(addr);
878 return err;
879 }
880
881 /* Returns: 0 - drop, !=0 - accept */
882 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
883 {
884 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
885 * at this point. */
886 struct ethhdr *eh = (struct ethhdr *) skb->data;
887 int i;
888
889 /* Exact match */
890 for (i = 0; i < filter->count; i++)
891 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
892 return 1;
893
894 /* Inexact match (multicast only) */
895 if (is_multicast_ether_addr(eh->h_dest))
896 return addr_hash_test(filter->mask, eh->h_dest);
897
898 return 0;
899 }
900
901 /*
902 * Checks whether the packet is accepted or not.
903 * Returns: 0 - drop, !=0 - accept
904 */
905 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
906 {
907 if (!filter->count)
908 return 1;
909
910 return run_filter(filter, skb);
911 }
912
913 /* Network device part of the driver */
914
915 static const struct ethtool_ops tun_ethtool_ops;
916
917 /* Net device detach from fd. */
918 static void tun_net_uninit(struct net_device *dev)
919 {
920 tun_detach_all(dev);
921 }
922
923 /* Net device open. */
924 static int tun_net_open(struct net_device *dev)
925 {
926 struct tun_struct *tun = netdev_priv(dev);
927 int i;
928
929 netif_tx_start_all_queues(dev);
930
931 for (i = 0; i < tun->numqueues; i++) {
932 struct tun_file *tfile;
933
934 tfile = rtnl_dereference(tun->tfiles[i]);
935 tfile->socket.sk->sk_write_space(tfile->socket.sk);
936 }
937
938 return 0;
939 }
940
941 /* Net device close. */
942 static int tun_net_close(struct net_device *dev)
943 {
944 netif_tx_stop_all_queues(dev);
945 return 0;
946 }
947
948 /* Net device start xmit */
949 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
950 {
951 struct tun_struct *tun = netdev_priv(dev);
952 int txq = skb->queue_mapping;
953 struct tun_file *tfile;
954 u32 numqueues = 0;
955
956 rcu_read_lock();
957 tfile = rcu_dereference(tun->tfiles[txq]);
958 numqueues = READ_ONCE(tun->numqueues);
959
960 /* Drop packet if interface is not attached */
961 if (txq >= numqueues)
962 goto drop;
963
964 #ifdef CONFIG_RPS
965 if (numqueues == 1 && static_key_false(&rps_needed)) {
966 /* Select queue was not called for the skbuff, so we extract the
967 * RPS hash and save it into the flow_table here.
968 */
969 __u32 rxhash;
970
971 rxhash = __skb_get_hash_symmetric(skb);
972 if (rxhash) {
973 struct tun_flow_entry *e;
974 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)],
975 rxhash);
976 if (e)
977 tun_flow_save_rps_rxhash(e, rxhash);
978 }
979 }
980 #endif
981
982 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
983
984 BUG_ON(!tfile);
985
986 /* Drop if the filter does not like it.
987 * This is a noop if the filter is disabled.
988 * Filter can be enabled only for the TAP devices. */
989 if (!check_filter(&tun->txflt, skb))
990 goto drop;
991
992 if (tfile->socket.sk->sk_filter &&
993 sk_filter(tfile->socket.sk, skb))
994 goto drop;
995
996 if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC)))
997 goto drop;
998
999 skb_tx_timestamp(skb);
1000
1001 /* Orphan the skb - required as we might hang on to it
1002 * for indefinite time.
1003 */
1004 skb_orphan(skb);
1005
1006 nf_reset(skb);
1007
1008 if (skb_array_produce(&tfile->tx_array, skb))
1009 goto drop;
1010
1011 /* Notify and wake up reader process */
1012 if (tfile->flags & TUN_FASYNC)
1013 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1014 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1015
1016 rcu_read_unlock();
1017 return NETDEV_TX_OK;
1018
1019 drop:
1020 this_cpu_inc(tun->pcpu_stats->tx_dropped);
1021 skb_tx_error(skb);
1022 kfree_skb(skb);
1023 rcu_read_unlock();
1024 return NET_XMIT_DROP;
1025 }
1026
1027 static void tun_net_mclist(struct net_device *dev)
1028 {
1029 /*
1030 * This callback is supposed to deal with mc filter in
1031 * _rx_ path and has nothing to do with the _tx_ path.
1032 * In rx path we always accept everything userspace gives us.
1033 */
1034 }
1035
1036 static netdev_features_t tun_net_fix_features(struct net_device *dev,
1037 netdev_features_t features)
1038 {
1039 struct tun_struct *tun = netdev_priv(dev);
1040
1041 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
1042 }
1043 #ifdef CONFIG_NET_POLL_CONTROLLER
1044 static void tun_poll_controller(struct net_device *dev)
1045 {
1046 /*
1047 * Tun only receives frames when:
1048 * 1) the char device endpoint gets data from user space
1049 * 2) the tun socket gets a sendmsg call from user space
1050 * If NAPI is not enabled, since both of those are synchronous
1051 * operations, we are guaranteed never to have pending data when we poll
1052 * for it so there is nothing to do here but return.
1053 * We need this though so netpoll recognizes us as an interface that
1054 * supports polling, which enables bridge devices in virt setups to
1055 * still use netconsole
1056 * If NAPI is enabled, however, we need to schedule polling for all
1057 * queues unless we are using napi_gro_frags(), which we call in
1058 * process context and not in NAPI context.
1059 */
1060 struct tun_struct *tun = netdev_priv(dev);
1061
1062 if (tun->flags & IFF_NAPI) {
1063 struct tun_file *tfile;
1064 int i;
1065
1066 if (tun_napi_frags_enabled(tun))
1067 return;
1068
1069 rcu_read_lock();
1070 for (i = 0; i < tun->numqueues; i++) {
1071 tfile = rcu_dereference(tun->tfiles[i]);
1072 if (tfile->napi_enabled)
1073 napi_schedule(&tfile->napi);
1074 }
1075 rcu_read_unlock();
1076 }
1077 return;
1078 }
1079 #endif
1080
1081 static void tun_set_headroom(struct net_device *dev, int new_hr)
1082 {
1083 struct tun_struct *tun = netdev_priv(dev);
1084
1085 if (new_hr < NET_SKB_PAD)
1086 new_hr = NET_SKB_PAD;
1087
1088 tun->align = new_hr;
1089 }
1090
1091 static void
1092 tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
1093 {
1094 u32 rx_dropped = 0, tx_dropped = 0, rx_frame_errors = 0;
1095 struct tun_struct *tun = netdev_priv(dev);
1096 struct tun_pcpu_stats *p;
1097 int i;
1098
1099 for_each_possible_cpu(i) {
1100 u64 rxpackets, rxbytes, txpackets, txbytes;
1101 unsigned int start;
1102
1103 p = per_cpu_ptr(tun->pcpu_stats, i);
1104 do {
1105 start = u64_stats_fetch_begin(&p->syncp);
1106 rxpackets = p->rx_packets;
1107 rxbytes = p->rx_bytes;
1108 txpackets = p->tx_packets;
1109 txbytes = p->tx_bytes;
1110 } while (u64_stats_fetch_retry(&p->syncp, start));
1111
1112 stats->rx_packets += rxpackets;
1113 stats->rx_bytes += rxbytes;
1114 stats->tx_packets += txpackets;
1115 stats->tx_bytes += txbytes;
1116
1117 /* u32 counters */
1118 rx_dropped += p->rx_dropped;
1119 rx_frame_errors += p->rx_frame_errors;
1120 tx_dropped += p->tx_dropped;
1121 }
1122 stats->rx_dropped = rx_dropped;
1123 stats->rx_frame_errors = rx_frame_errors;
1124 stats->tx_dropped = tx_dropped;
1125 }
1126
1127 static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1128 struct netlink_ext_ack *extack)
1129 {
1130 struct tun_struct *tun = netdev_priv(dev);
1131 struct bpf_prog *old_prog;
1132
1133 old_prog = rtnl_dereference(tun->xdp_prog);
1134 rcu_assign_pointer(tun->xdp_prog, prog);
1135 if (old_prog)
1136 bpf_prog_put(old_prog);
1137
1138 return 0;
1139 }
1140
1141 static u32 tun_xdp_query(struct net_device *dev)
1142 {
1143 struct tun_struct *tun = netdev_priv(dev);
1144 const struct bpf_prog *xdp_prog;
1145
1146 xdp_prog = rtnl_dereference(tun->xdp_prog);
1147 if (xdp_prog)
1148 return xdp_prog->aux->id;
1149
1150 return 0;
1151 }
1152
1153 static int tun_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1154 {
1155 switch (xdp->command) {
1156 case XDP_SETUP_PROG:
1157 return tun_xdp_set(dev, xdp->prog, xdp->extack);
1158 case XDP_QUERY_PROG:
1159 xdp->prog_id = tun_xdp_query(dev);
1160 xdp->prog_attached = !!xdp->prog_id;
1161 return 0;
1162 default:
1163 return -EINVAL;
1164 }
1165 }
1166
1167 static const struct net_device_ops tun_netdev_ops = {
1168 .ndo_uninit = tun_net_uninit,
1169 .ndo_open = tun_net_open,
1170 .ndo_stop = tun_net_close,
1171 .ndo_start_xmit = tun_net_xmit,
1172 .ndo_fix_features = tun_net_fix_features,
1173 .ndo_select_queue = tun_select_queue,
1174 #ifdef CONFIG_NET_POLL_CONTROLLER
1175 .ndo_poll_controller = tun_poll_controller,
1176 #endif
1177 .ndo_set_rx_headroom = tun_set_headroom,
1178 .ndo_get_stats64 = tun_net_get_stats64,
1179 };
1180
1181 static const struct net_device_ops tap_netdev_ops = {
1182 .ndo_uninit = tun_net_uninit,
1183 .ndo_open = tun_net_open,
1184 .ndo_stop = tun_net_close,
1185 .ndo_start_xmit = tun_net_xmit,
1186 .ndo_fix_features = tun_net_fix_features,
1187 .ndo_set_rx_mode = tun_net_mclist,
1188 .ndo_set_mac_address = eth_mac_addr,
1189 .ndo_validate_addr = eth_validate_addr,
1190 .ndo_select_queue = tun_select_queue,
1191 #ifdef CONFIG_NET_POLL_CONTROLLER
1192 .ndo_poll_controller = tun_poll_controller,
1193 #endif
1194 .ndo_features_check = passthru_features_check,
1195 .ndo_set_rx_headroom = tun_set_headroom,
1196 .ndo_get_stats64 = tun_net_get_stats64,
1197 .ndo_bpf = tun_xdp,
1198 };
1199
1200 static void tun_flow_init(struct tun_struct *tun)
1201 {
1202 int i;
1203
1204 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1205 INIT_HLIST_HEAD(&tun->flows[i]);
1206
1207 tun->ageing_time = TUN_FLOW_EXPIRE;
1208 timer_setup(&tun->flow_gc_timer, tun_flow_cleanup, 0);
1209 mod_timer(&tun->flow_gc_timer,
1210 round_jiffies_up(jiffies + tun->ageing_time));
1211 }
1212
1213 static void tun_flow_uninit(struct tun_struct *tun)
1214 {
1215 del_timer_sync(&tun->flow_gc_timer);
1216 tun_flow_flush(tun);
1217 }
1218
1219 #define MIN_MTU 68
1220 #define MAX_MTU 65535
1221
1222 /* Initialize net device. */
1223 static void tun_net_init(struct net_device *dev)
1224 {
1225 struct tun_struct *tun = netdev_priv(dev);
1226
1227 switch (tun->flags & TUN_TYPE_MASK) {
1228 case IFF_TUN:
1229 dev->netdev_ops = &tun_netdev_ops;
1230
1231 /* Point-to-Point TUN Device */
1232 dev->hard_header_len = 0;
1233 dev->addr_len = 0;
1234 dev->mtu = 1500;
1235
1236 /* Zero header length */
1237 dev->type = ARPHRD_NONE;
1238 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1239 break;
1240
1241 case IFF_TAP:
1242 dev->netdev_ops = &tap_netdev_ops;
1243 /* Ethernet TAP Device */
1244 ether_setup(dev);
1245 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1246 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1247
1248 eth_hw_addr_random(dev);
1249
1250 break;
1251 }
1252
1253 dev->min_mtu = MIN_MTU;
1254 dev->max_mtu = MAX_MTU - dev->hard_header_len;
1255 }
1256
1257 /* Character device part */
1258
1259 /* Poll */
1260 static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
1261 {
1262 struct tun_file *tfile = file->private_data;
1263 struct tun_struct *tun = tun_get(tfile);
1264 struct sock *sk;
1265 unsigned int mask = 0;
1266
1267 if (!tun)
1268 return POLLERR;
1269
1270 sk = tfile->socket.sk;
1271
1272 tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
1273
1274 poll_wait(file, sk_sleep(sk), wait);
1275
1276 if (!skb_array_empty(&tfile->tx_array))
1277 mask |= POLLIN | POLLRDNORM;
1278
1279 if (tun->dev->flags & IFF_UP &&
1280 (sock_writeable(sk) ||
1281 (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1282 sock_writeable(sk))))
1283 mask |= POLLOUT | POLLWRNORM;
1284
1285 if (tun->dev->reg_state != NETREG_REGISTERED)
1286 mask = POLLERR;
1287
1288 tun_put(tun);
1289 return mask;
1290 }
1291
1292 static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile,
1293 size_t len,
1294 const struct iov_iter *it)
1295 {
1296 struct sk_buff *skb;
1297 size_t linear;
1298 int err;
1299 int i;
1300
1301 if (it->nr_segs > MAX_SKB_FRAGS + 1)
1302 return ERR_PTR(-ENOMEM);
1303
1304 local_bh_disable();
1305 skb = napi_get_frags(&tfile->napi);
1306 local_bh_enable();
1307 if (!skb)
1308 return ERR_PTR(-ENOMEM);
1309
1310 linear = iov_iter_single_seg_count(it);
1311 err = __skb_grow(skb, linear);
1312 if (err)
1313 goto free;
1314
1315 skb->len = len;
1316 skb->data_len = len - linear;
1317 skb->truesize += skb->data_len;
1318
1319 for (i = 1; i < it->nr_segs; i++) {
1320 struct page_frag *pfrag = &current->task_frag;
1321 size_t fragsz = it->iov[i].iov_len;
1322
1323 if (fragsz == 0 || fragsz > PAGE_SIZE) {
1324 err = -EINVAL;
1325 goto free;
1326 }
1327
1328 if (!skb_page_frag_refill(fragsz, pfrag, GFP_KERNEL)) {
1329 err = -ENOMEM;
1330 goto free;
1331 }
1332
1333 skb_fill_page_desc(skb, i - 1, pfrag->page,
1334 pfrag->offset, fragsz);
1335 page_ref_inc(pfrag->page);
1336 pfrag->offset += fragsz;
1337 }
1338
1339 return skb;
1340 free:
1341 /* frees skb and all frags allocated with napi_alloc_frag() */
1342 napi_free_frags(&tfile->napi);
1343 return ERR_PTR(err);
1344 }
1345
1346 /* prepad is the amount to reserve at front. len is length after that.
1347 * linear is a hint as to how much to copy (usually headers). */
1348 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1349 size_t prepad, size_t len,
1350 size_t linear, int noblock)
1351 {
1352 struct sock *sk = tfile->socket.sk;
1353 struct sk_buff *skb;
1354 int err;
1355
1356 /* Under a page? Don't bother with paged skb. */
1357 if (prepad + len < PAGE_SIZE || !linear)
1358 linear = len;
1359
1360 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1361 &err, 0);
1362 if (!skb)
1363 return ERR_PTR(err);
1364
1365 skb_reserve(skb, prepad);
1366 skb_put(skb, linear);
1367 skb->data_len = len - linear;
1368 skb->len += len - linear;
1369
1370 return skb;
1371 }
1372
1373 static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile,
1374 struct sk_buff *skb, int more)
1375 {
1376 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1377 struct sk_buff_head process_queue;
1378 u32 rx_batched = tun->rx_batched;
1379 bool rcv = false;
1380
1381 if (!rx_batched || (!more && skb_queue_empty(queue))) {
1382 local_bh_disable();
1383 netif_receive_skb(skb);
1384 local_bh_enable();
1385 return;
1386 }
1387
1388 spin_lock(&queue->lock);
1389 if (!more || skb_queue_len(queue) == rx_batched) {
1390 __skb_queue_head_init(&process_queue);
1391 skb_queue_splice_tail_init(queue, &process_queue);
1392 rcv = true;
1393 } else {
1394 __skb_queue_tail(queue, skb);
1395 }
1396 spin_unlock(&queue->lock);
1397
1398 if (rcv) {
1399 struct sk_buff *nskb;
1400
1401 local_bh_disable();
1402 while ((nskb = __skb_dequeue(&process_queue)))
1403 netif_receive_skb(nskb);
1404 netif_receive_skb(skb);
1405 local_bh_enable();
1406 }
1407 }
1408
1409 static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile,
1410 int len, int noblock, bool zerocopy)
1411 {
1412 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
1413 return false;
1414
1415 if (tfile->socket.sk->sk_sndbuf != INT_MAX)
1416 return false;
1417
1418 if (!noblock)
1419 return false;
1420
1421 if (zerocopy)
1422 return false;
1423
1424 if (SKB_DATA_ALIGN(len + TUN_RX_PAD) +
1425 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
1426 return false;
1427
1428 return true;
1429 }
1430
1431 static struct sk_buff *tun_build_skb(struct tun_struct *tun,
1432 struct tun_file *tfile,
1433 struct iov_iter *from,
1434 struct virtio_net_hdr *hdr,
1435 int len, int *skb_xdp)
1436 {
1437 struct page_frag *alloc_frag = &current->task_frag;
1438 struct sk_buff *skb;
1439 struct bpf_prog *xdp_prog;
1440 int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1441 unsigned int delta = 0;
1442 char *buf;
1443 size_t copied;
1444 bool xdp_xmit = false;
1445 int err, pad = TUN_RX_PAD;
1446
1447 rcu_read_lock();
1448 xdp_prog = rcu_dereference(tun->xdp_prog);
1449 if (xdp_prog)
1450 pad += TUN_HEADROOM;
1451 buflen += SKB_DATA_ALIGN(len + pad);
1452 rcu_read_unlock();
1453
1454 alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES);
1455 if (unlikely(!skb_page_frag_refill(buflen, alloc_frag, GFP_KERNEL)))
1456 return ERR_PTR(-ENOMEM);
1457
1458 buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
1459 copied = copy_page_from_iter(alloc_frag->page,
1460 alloc_frag->offset + pad,
1461 len, from);
1462 if (copied != len)
1463 return ERR_PTR(-EFAULT);
1464
1465 /* There's a small window that XDP may be set after the check
1466 * of xdp_prog above, this should be rare and for simplicity
1467 * we do XDP on skb in case the headroom is not enough.
1468 */
1469 if (hdr->gso_type || !xdp_prog)
1470 *skb_xdp = 1;
1471 else
1472 *skb_xdp = 0;
1473
1474 rcu_read_lock();
1475 xdp_prog = rcu_dereference(tun->xdp_prog);
1476 if (xdp_prog && !*skb_xdp) {
1477 struct xdp_buff xdp;
1478 void *orig_data;
1479 u32 act;
1480
1481 xdp.data_hard_start = buf;
1482 xdp.data = buf + pad;
1483 xdp_set_data_meta_invalid(&xdp);
1484 xdp.data_end = xdp.data + len;
1485 orig_data = xdp.data;
1486 act = bpf_prog_run_xdp(xdp_prog, &xdp);
1487
1488 switch (act) {
1489 case XDP_REDIRECT:
1490 get_page(alloc_frag->page);
1491 alloc_frag->offset += buflen;
1492 err = xdp_do_redirect(tun->dev, &xdp, xdp_prog);
1493 if (err)
1494 goto err_redirect;
1495 rcu_read_unlock();
1496 return NULL;
1497 case XDP_TX:
1498 xdp_xmit = true;
1499 /* fall through */
1500 case XDP_PASS:
1501 delta = orig_data - xdp.data;
1502 break;
1503 default:
1504 bpf_warn_invalid_xdp_action(act);
1505 /* fall through */
1506 case XDP_ABORTED:
1507 trace_xdp_exception(tun->dev, xdp_prog, act);
1508 /* fall through */
1509 case XDP_DROP:
1510 goto err_xdp;
1511 }
1512 }
1513
1514 skb = build_skb(buf, buflen);
1515 if (!skb) {
1516 rcu_read_unlock();
1517 return ERR_PTR(-ENOMEM);
1518 }
1519
1520 skb_reserve(skb, pad - delta);
1521 skb_put(skb, len + delta);
1522 get_page(alloc_frag->page);
1523 alloc_frag->offset += buflen;
1524
1525 if (xdp_xmit) {
1526 skb->dev = tun->dev;
1527 generic_xdp_tx(skb, xdp_prog);
1528 rcu_read_unlock();
1529 return NULL;
1530 }
1531
1532 rcu_read_unlock();
1533
1534 return skb;
1535
1536 err_redirect:
1537 put_page(alloc_frag->page);
1538 err_xdp:
1539 rcu_read_unlock();
1540 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1541 return NULL;
1542 }
1543
1544 /* Get packet from user space buffer */
1545 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1546 void *msg_control, struct iov_iter *from,
1547 int noblock, bool more)
1548 {
1549 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1550 struct sk_buff *skb;
1551 size_t total_len = iov_iter_count(from);
1552 size_t len = total_len, align = tun->align, linear;
1553 struct virtio_net_hdr gso = { 0 };
1554 struct tun_pcpu_stats *stats;
1555 int good_linear;
1556 int copylen;
1557 bool zerocopy = false;
1558 int err;
1559 u32 rxhash;
1560 int skb_xdp = 1;
1561 bool frags = tun_napi_frags_enabled(tun);
1562
1563 if (!(tun->dev->flags & IFF_UP))
1564 return -EIO;
1565
1566 if (!(tun->flags & IFF_NO_PI)) {
1567 if (len < sizeof(pi))
1568 return -EINVAL;
1569 len -= sizeof(pi);
1570
1571 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1572 return -EFAULT;
1573 }
1574
1575 if (tun->flags & IFF_VNET_HDR) {
1576 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1577
1578 if (len < vnet_hdr_sz)
1579 return -EINVAL;
1580 len -= vnet_hdr_sz;
1581
1582 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1583 return -EFAULT;
1584
1585 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1586 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1587 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1588
1589 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1590 return -EINVAL;
1591 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1592 }
1593
1594 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1595 align += NET_IP_ALIGN;
1596 if (unlikely(len < ETH_HLEN ||
1597 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1598 return -EINVAL;
1599 }
1600
1601 good_linear = SKB_MAX_HEAD(align);
1602
1603 if (msg_control) {
1604 struct iov_iter i = *from;
1605
1606 /* There are 256 bytes to be copied in skb, so there is
1607 * enough room for skb expand head in case it is used.
1608 * The rest of the buffer is mapped from userspace.
1609 */
1610 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1611 if (copylen > good_linear)
1612 copylen = good_linear;
1613 linear = copylen;
1614 iov_iter_advance(&i, copylen);
1615 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1616 zerocopy = true;
1617 }
1618
1619 if (!frags && tun_can_build_skb(tun, tfile, len, noblock, zerocopy)) {
1620 /* For the packet that is not easy to be processed
1621 * (e.g gso or jumbo packet), we will do it at after
1622 * skb was created with generic XDP routine.
1623 */
1624 skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp);
1625 if (IS_ERR(skb)) {
1626 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1627 return PTR_ERR(skb);
1628 }
1629 if (!skb)
1630 return total_len;
1631 } else {
1632 if (!zerocopy) {
1633 copylen = len;
1634 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1635 linear = good_linear;
1636 else
1637 linear = tun16_to_cpu(tun, gso.hdr_len);
1638 }
1639
1640 if (frags) {
1641 mutex_lock(&tfile->napi_mutex);
1642 skb = tun_napi_alloc_frags(tfile, copylen, from);
1643 /* tun_napi_alloc_frags() enforces a layout for the skb.
1644 * If zerocopy is enabled, then this layout will be
1645 * overwritten by zerocopy_sg_from_iter().
1646 */
1647 zerocopy = false;
1648 } else {
1649 skb = tun_alloc_skb(tfile, align, copylen, linear,
1650 noblock);
1651 }
1652
1653 if (IS_ERR(skb)) {
1654 if (PTR_ERR(skb) != -EAGAIN)
1655 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1656 if (frags)
1657 mutex_unlock(&tfile->napi_mutex);
1658 return PTR_ERR(skb);
1659 }
1660
1661 if (zerocopy)
1662 err = zerocopy_sg_from_iter(skb, from);
1663 else
1664 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1665
1666 if (err) {
1667 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1668 kfree_skb(skb);
1669 if (frags) {
1670 tfile->napi.skb = NULL;
1671 mutex_unlock(&tfile->napi_mutex);
1672 }
1673
1674 return -EFAULT;
1675 }
1676 }
1677
1678 if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1679 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
1680 kfree_skb(skb);
1681 if (frags) {
1682 tfile->napi.skb = NULL;
1683 mutex_unlock(&tfile->napi_mutex);
1684 }
1685
1686 return -EINVAL;
1687 }
1688
1689 switch (tun->flags & TUN_TYPE_MASK) {
1690 case IFF_TUN:
1691 if (tun->flags & IFF_NO_PI) {
1692 u8 ip_version = skb->len ? (skb->data[0] >> 4) : 0;
1693
1694 switch (ip_version) {
1695 case 4:
1696 pi.proto = htons(ETH_P_IP);
1697 break;
1698 case 6:
1699 pi.proto = htons(ETH_P_IPV6);
1700 break;
1701 default:
1702 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1703 kfree_skb(skb);
1704 return -EINVAL;
1705 }
1706 }
1707
1708 skb_reset_mac_header(skb);
1709 skb->protocol = pi.proto;
1710 skb->dev = tun->dev;
1711 break;
1712 case IFF_TAP:
1713 if (!frags)
1714 skb->protocol = eth_type_trans(skb, tun->dev);
1715 break;
1716 }
1717
1718 /* copy skb_ubuf_info for callback when skb has no error */
1719 if (zerocopy) {
1720 skb_shinfo(skb)->destructor_arg = msg_control;
1721 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1722 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1723 } else if (msg_control) {
1724 struct ubuf_info *uarg = msg_control;
1725 uarg->callback(uarg, false);
1726 }
1727
1728 skb_reset_network_header(skb);
1729 skb_probe_transport_header(skb, 0);
1730
1731 if (skb_xdp) {
1732 struct bpf_prog *xdp_prog;
1733 int ret;
1734
1735 rcu_read_lock();
1736 xdp_prog = rcu_dereference(tun->xdp_prog);
1737 if (xdp_prog) {
1738 ret = do_xdp_generic(xdp_prog, skb);
1739 if (ret != XDP_PASS) {
1740 rcu_read_unlock();
1741 return total_len;
1742 }
1743 }
1744 rcu_read_unlock();
1745 }
1746
1747 rxhash = __skb_get_hash_symmetric(skb);
1748
1749 if (frags) {
1750 /* Exercise flow dissector code path. */
1751 u32 headlen = eth_get_headlen(skb->data, skb_headlen(skb));
1752
1753 if (unlikely(headlen > skb_headlen(skb))) {
1754 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1755 napi_free_frags(&tfile->napi);
1756 mutex_unlock(&tfile->napi_mutex);
1757 WARN_ON(1);
1758 return -ENOMEM;
1759 }
1760
1761 local_bh_disable();
1762 napi_gro_frags(&tfile->napi);
1763 local_bh_enable();
1764 mutex_unlock(&tfile->napi_mutex);
1765 } else if (tfile->napi_enabled) {
1766 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1767 int queue_len;
1768
1769 spin_lock_bh(&queue->lock);
1770 __skb_queue_tail(queue, skb);
1771 queue_len = skb_queue_len(queue);
1772 spin_unlock(&queue->lock);
1773
1774 if (!more || queue_len > NAPI_POLL_WEIGHT)
1775 napi_schedule(&tfile->napi);
1776
1777 local_bh_enable();
1778 } else if (!IS_ENABLED(CONFIG_4KSTACKS)) {
1779 tun_rx_batched(tun, tfile, skb, more);
1780 } else {
1781 netif_rx_ni(skb);
1782 }
1783
1784 stats = get_cpu_ptr(tun->pcpu_stats);
1785 u64_stats_update_begin(&stats->syncp);
1786 stats->rx_packets++;
1787 stats->rx_bytes += len;
1788 u64_stats_update_end(&stats->syncp);
1789 put_cpu_ptr(stats);
1790
1791 tun_flow_update(tun, rxhash, tfile);
1792 return total_len;
1793 }
1794
1795 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
1796 {
1797 struct file *file = iocb->ki_filp;
1798 struct tun_file *tfile = file->private_data;
1799 struct tun_struct *tun = tun_get(tfile);
1800 ssize_t result;
1801
1802 if (!tun)
1803 return -EBADFD;
1804
1805 result = tun_get_user(tun, tfile, NULL, from,
1806 file->f_flags & O_NONBLOCK, false);
1807
1808 tun_put(tun);
1809 return result;
1810 }
1811
1812 /* Put packet to the user space buffer */
1813 static ssize_t tun_put_user(struct tun_struct *tun,
1814 struct tun_file *tfile,
1815 struct sk_buff *skb,
1816 struct iov_iter *iter)
1817 {
1818 struct tun_pi pi = { 0, skb->protocol };
1819 struct tun_pcpu_stats *stats;
1820 ssize_t total;
1821 int vlan_offset = 0;
1822 int vlan_hlen = 0;
1823 int vnet_hdr_sz = 0;
1824
1825 if (skb_vlan_tag_present(skb))
1826 vlan_hlen = VLAN_HLEN;
1827
1828 if (tun->flags & IFF_VNET_HDR)
1829 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1830
1831 total = skb->len + vlan_hlen + vnet_hdr_sz;
1832
1833 if (!(tun->flags & IFF_NO_PI)) {
1834 if (iov_iter_count(iter) < sizeof(pi))
1835 return -EINVAL;
1836
1837 total += sizeof(pi);
1838 if (iov_iter_count(iter) < total) {
1839 /* Packet will be striped */
1840 pi.flags |= TUN_PKT_STRIP;
1841 }
1842
1843 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
1844 return -EFAULT;
1845 }
1846
1847 if (vnet_hdr_sz) {
1848 struct virtio_net_hdr gso;
1849
1850 if (iov_iter_count(iter) < vnet_hdr_sz)
1851 return -EINVAL;
1852
1853 if (virtio_net_hdr_from_skb(skb, &gso,
1854 tun_is_little_endian(tun), true)) {
1855 struct skb_shared_info *sinfo = skb_shinfo(skb);
1856 pr_err("unexpected GSO type: "
1857 "0x%x, gso_size %d, hdr_len %d\n",
1858 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
1859 tun16_to_cpu(tun, gso.hdr_len));
1860 print_hex_dump(KERN_ERR, "tun: ",
1861 DUMP_PREFIX_NONE,
1862 16, 1, skb->head,
1863 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
1864 WARN_ON_ONCE(1);
1865 return -EINVAL;
1866 }
1867
1868 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
1869 return -EFAULT;
1870
1871 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
1872 }
1873
1874 if (vlan_hlen) {
1875 int ret;
1876 struct {
1877 __be16 h_vlan_proto;
1878 __be16 h_vlan_TCI;
1879 } veth;
1880
1881 veth.h_vlan_proto = skb->vlan_proto;
1882 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
1883
1884 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
1885
1886 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
1887 if (ret || !iov_iter_count(iter))
1888 goto done;
1889
1890 ret = copy_to_iter(&veth, sizeof(veth), iter);
1891 if (ret != sizeof(veth) || !iov_iter_count(iter))
1892 goto done;
1893 }
1894
1895 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
1896
1897 done:
1898 /* caller is in process context, */
1899 stats = get_cpu_ptr(tun->pcpu_stats);
1900 u64_stats_update_begin(&stats->syncp);
1901 stats->tx_packets++;
1902 stats->tx_bytes += skb->len + vlan_hlen;
1903 u64_stats_update_end(&stats->syncp);
1904 put_cpu_ptr(tun->pcpu_stats);
1905
1906 return total;
1907 }
1908
1909 static struct sk_buff *tun_ring_recv(struct tun_file *tfile, int noblock,
1910 int *err)
1911 {
1912 DECLARE_WAITQUEUE(wait, current);
1913 struct sk_buff *skb = NULL;
1914 int error = 0;
1915
1916 skb = skb_array_consume(&tfile->tx_array);
1917 if (skb)
1918 goto out;
1919 if (noblock) {
1920 error = -EAGAIN;
1921 goto out;
1922 }
1923
1924 add_wait_queue(&tfile->wq.wait, &wait);
1925 current->state = TASK_INTERRUPTIBLE;
1926
1927 while (1) {
1928 skb = skb_array_consume(&tfile->tx_array);
1929 if (skb)
1930 break;
1931 if (signal_pending(current)) {
1932 error = -ERESTARTSYS;
1933 break;
1934 }
1935 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
1936 error = -EFAULT;
1937 break;
1938 }
1939
1940 schedule();
1941 }
1942
1943 current->state = TASK_RUNNING;
1944 remove_wait_queue(&tfile->wq.wait, &wait);
1945
1946 out:
1947 *err = error;
1948 return skb;
1949 }
1950
1951 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
1952 struct iov_iter *to,
1953 int noblock, struct sk_buff *skb)
1954 {
1955 ssize_t ret;
1956 int err;
1957
1958 tun_debug(KERN_INFO, tun, "tun_do_read\n");
1959
1960 if (!iov_iter_count(to)) {
1961 if (skb)
1962 kfree_skb(skb);
1963 return 0;
1964 }
1965
1966 if (!skb) {
1967 /* Read frames from ring */
1968 skb = tun_ring_recv(tfile, noblock, &err);
1969 if (!skb)
1970 return err;
1971 }
1972
1973 ret = tun_put_user(tun, tfile, skb, to);
1974 if (unlikely(ret < 0))
1975 kfree_skb(skb);
1976 else
1977 consume_skb(skb);
1978
1979 return ret;
1980 }
1981
1982 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
1983 {
1984 struct file *file = iocb->ki_filp;
1985 struct tun_file *tfile = file->private_data;
1986 struct tun_struct *tun = tun_get(tfile);
1987 ssize_t len = iov_iter_count(to), ret;
1988
1989 if (!tun)
1990 return -EBADFD;
1991 ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK, NULL);
1992 ret = min_t(ssize_t, ret, len);
1993 if (ret > 0)
1994 iocb->ki_pos = ret;
1995 tun_put(tun);
1996 return ret;
1997 }
1998
1999 static void tun_free_netdev(struct net_device *dev)
2000 {
2001 struct tun_struct *tun = netdev_priv(dev);
2002
2003 BUG_ON(!(list_empty(&tun->disabled)));
2004 free_percpu(tun->pcpu_stats);
2005 tun_flow_uninit(tun);
2006 security_tun_dev_free_security(tun->security);
2007 }
2008
2009 static void tun_setup(struct net_device *dev)
2010 {
2011 struct tun_struct *tun = netdev_priv(dev);
2012
2013 tun->owner = INVALID_UID;
2014 tun->group = INVALID_GID;
2015
2016 dev->ethtool_ops = &tun_ethtool_ops;
2017 dev->needs_free_netdev = true;
2018 dev->priv_destructor = tun_free_netdev;
2019 /* We prefer our own queue length */
2020 dev->tx_queue_len = TUN_READQ_SIZE;
2021 }
2022
2023 /* Trivial set of netlink ops to allow deleting tun or tap
2024 * device with netlink.
2025 */
2026 static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
2027 struct netlink_ext_ack *extack)
2028 {
2029 return -EINVAL;
2030 }
2031
2032 static struct rtnl_link_ops tun_link_ops __read_mostly = {
2033 .kind = DRV_NAME,
2034 .priv_size = sizeof(struct tun_struct),
2035 .setup = tun_setup,
2036 .validate = tun_validate,
2037 };
2038
2039 static void tun_sock_write_space(struct sock *sk)
2040 {
2041 struct tun_file *tfile;
2042 wait_queue_head_t *wqueue;
2043
2044 if (!sock_writeable(sk))
2045 return;
2046
2047 if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
2048 return;
2049
2050 wqueue = sk_sleep(sk);
2051 if (wqueue && waitqueue_active(wqueue))
2052 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
2053 POLLWRNORM | POLLWRBAND);
2054
2055 tfile = container_of(sk, struct tun_file, sk);
2056 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
2057 }
2058
2059 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
2060 {
2061 int ret;
2062 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2063 struct tun_struct *tun = tun_get(tfile);
2064
2065 if (!tun)
2066 return -EBADFD;
2067
2068 ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter,
2069 m->msg_flags & MSG_DONTWAIT,
2070 m->msg_flags & MSG_MORE);
2071 tun_put(tun);
2072 return ret;
2073 }
2074
2075 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
2076 int flags)
2077 {
2078 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2079 struct tun_struct *tun = tun_get(tfile);
2080 struct sk_buff *skb = m->msg_control;
2081 int ret;
2082
2083 if (!tun) {
2084 ret = -EBADFD;
2085 goto out_free_skb;
2086 }
2087
2088 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
2089 ret = -EINVAL;
2090 goto out_put_tun;
2091 }
2092 if (flags & MSG_ERRQUEUE) {
2093 ret = sock_recv_errqueue(sock->sk, m, total_len,
2094 SOL_PACKET, TUN_TX_TIMESTAMP);
2095 goto out;
2096 }
2097 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT, skb);
2098 if (ret > (ssize_t)total_len) {
2099 m->msg_flags |= MSG_TRUNC;
2100 ret = flags & MSG_TRUNC ? ret : total_len;
2101 }
2102 out:
2103 tun_put(tun);
2104 return ret;
2105
2106 out_put_tun:
2107 tun_put(tun);
2108 out_free_skb:
2109 if (skb)
2110 kfree_skb(skb);
2111 return ret;
2112 }
2113
2114 static int tun_peek_len(struct socket *sock)
2115 {
2116 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2117 struct tun_struct *tun;
2118 int ret = 0;
2119
2120 tun = tun_get(tfile);
2121 if (!tun)
2122 return 0;
2123
2124 ret = skb_array_peek_len(&tfile->tx_array);
2125 tun_put(tun);
2126
2127 return ret;
2128 }
2129
2130 /* Ops structure to mimic raw sockets with tun */
2131 static const struct proto_ops tun_socket_ops = {
2132 .peek_len = tun_peek_len,
2133 .sendmsg = tun_sendmsg,
2134 .recvmsg = tun_recvmsg,
2135 };
2136
2137 static struct proto tun_proto = {
2138 .name = "tun",
2139 .owner = THIS_MODULE,
2140 .obj_size = sizeof(struct tun_file),
2141 };
2142
2143 static int tun_flags(struct tun_struct *tun)
2144 {
2145 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
2146 }
2147
2148 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
2149 char *buf)
2150 {
2151 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2152 return sprintf(buf, "0x%x\n", tun_flags(tun));
2153 }
2154
2155 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
2156 char *buf)
2157 {
2158 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2159 return uid_valid(tun->owner)?
2160 sprintf(buf, "%u\n",
2161 from_kuid_munged(current_user_ns(), tun->owner)):
2162 sprintf(buf, "-1\n");
2163 }
2164
2165 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
2166 char *buf)
2167 {
2168 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2169 return gid_valid(tun->group) ?
2170 sprintf(buf, "%u\n",
2171 from_kgid_munged(current_user_ns(), tun->group)):
2172 sprintf(buf, "-1\n");
2173 }
2174
2175 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
2176 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
2177 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
2178
2179 static struct attribute *tun_dev_attrs[] = {
2180 &dev_attr_tun_flags.attr,
2181 &dev_attr_owner.attr,
2182 &dev_attr_group.attr,
2183 NULL
2184 };
2185
2186 static const struct attribute_group tun_attr_group = {
2187 .attrs = tun_dev_attrs
2188 };
2189
2190 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
2191 {
2192 struct tun_struct *tun;
2193 struct tun_file *tfile = file->private_data;
2194 struct net_device *dev;
2195 int err;
2196
2197 if (tfile->detached)
2198 return -EINVAL;
2199
2200 if ((ifr->ifr_flags & IFF_NAPI_FRAGS)) {
2201 if (!capable(CAP_NET_ADMIN))
2202 return -EPERM;
2203
2204 if (!(ifr->ifr_flags & IFF_NAPI) ||
2205 (ifr->ifr_flags & TUN_TYPE_MASK) != IFF_TAP)
2206 return -EINVAL;
2207 }
2208
2209 dev = __dev_get_by_name(net, ifr->ifr_name);
2210 if (dev) {
2211 if (ifr->ifr_flags & IFF_TUN_EXCL)
2212 return -EBUSY;
2213 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
2214 tun = netdev_priv(dev);
2215 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
2216 tun = netdev_priv(dev);
2217 else
2218 return -EINVAL;
2219
2220 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
2221 !!(tun->flags & IFF_MULTI_QUEUE))
2222 return -EINVAL;
2223
2224 if (tun_not_capable(tun))
2225 return -EPERM;
2226 err = security_tun_dev_open(tun->security);
2227 if (err < 0)
2228 return err;
2229
2230 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER,
2231 ifr->ifr_flags & IFF_NAPI);
2232 if (err < 0)
2233 return err;
2234
2235 if (tun->flags & IFF_MULTI_QUEUE &&
2236 (tun->numqueues + tun->numdisabled > 1)) {
2237 /* One or more queue has already been attached, no need
2238 * to initialize the device again.
2239 */
2240 return 0;
2241 }
2242 }
2243 else {
2244 char *name;
2245 unsigned long flags = 0;
2246 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
2247 MAX_TAP_QUEUES : 1;
2248
2249 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2250 return -EPERM;
2251 err = security_tun_dev_create();
2252 if (err < 0)
2253 return err;
2254
2255 /* Set dev type */
2256 if (ifr->ifr_flags & IFF_TUN) {
2257 /* TUN device */
2258 flags |= IFF_TUN;
2259 name = "tun%d";
2260 } else if (ifr->ifr_flags & IFF_TAP) {
2261 /* TAP device */
2262 flags |= IFF_TAP;
2263 name = "tap%d";
2264 } else
2265 return -EINVAL;
2266
2267 if (*ifr->ifr_name)
2268 name = ifr->ifr_name;
2269
2270 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
2271 NET_NAME_UNKNOWN, tun_setup, queues,
2272 queues);
2273
2274 if (!dev)
2275 return -ENOMEM;
2276 err = dev_get_valid_name(net, dev, name);
2277 if (err < 0)
2278 goto err_free_dev;
2279
2280 dev_net_set(dev, net);
2281 dev->rtnl_link_ops = &tun_link_ops;
2282 dev->ifindex = tfile->ifindex;
2283 dev->sysfs_groups[0] = &tun_attr_group;
2284
2285 tun = netdev_priv(dev);
2286 tun->dev = dev;
2287 tun->flags = flags;
2288 tun->txflt.count = 0;
2289 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
2290
2291 tun->align = NET_SKB_PAD;
2292 tun->filter_attached = false;
2293 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
2294 tun->rx_batched = 0;
2295
2296 tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats);
2297 if (!tun->pcpu_stats) {
2298 err = -ENOMEM;
2299 goto err_free_dev;
2300 }
2301
2302 spin_lock_init(&tun->lock);
2303
2304 err = security_tun_dev_alloc_security(&tun->security);
2305 if (err < 0)
2306 goto err_free_stat;
2307
2308 tun_net_init(dev);
2309 tun_flow_init(tun);
2310
2311 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
2312 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
2313 NETIF_F_HW_VLAN_STAG_TX;
2314 dev->features = dev->hw_features | NETIF_F_LLTX;
2315 dev->vlan_features = dev->features &
2316 ~(NETIF_F_HW_VLAN_CTAG_TX |
2317 NETIF_F_HW_VLAN_STAG_TX);
2318
2319 INIT_LIST_HEAD(&tun->disabled);
2320 err = tun_attach(tun, file, false, ifr->ifr_flags & IFF_NAPI);
2321 if (err < 0)
2322 goto err_free_flow;
2323
2324 err = register_netdevice(tun->dev);
2325 if (err < 0)
2326 goto err_detach;
2327 }
2328
2329 netif_carrier_on(tun->dev);
2330
2331 tun_debug(KERN_INFO, tun, "tun_set_iff\n");
2332
2333 tun->flags = (tun->flags & ~TUN_FEATURES) |
2334 (ifr->ifr_flags & TUN_FEATURES);
2335
2336 /* Make sure persistent devices do not get stuck in
2337 * xoff state.
2338 */
2339 if (netif_running(tun->dev))
2340 netif_tx_wake_all_queues(tun->dev);
2341
2342 strcpy(ifr->ifr_name, tun->dev->name);
2343 return 0;
2344
2345 err_detach:
2346 tun_detach_all(dev);
2347 /* register_netdevice() already called tun_free_netdev() */
2348 goto err_free_dev;
2349
2350 err_free_flow:
2351 tun_flow_uninit(tun);
2352 security_tun_dev_free_security(tun->security);
2353 err_free_stat:
2354 free_percpu(tun->pcpu_stats);
2355 err_free_dev:
2356 free_netdev(dev);
2357 return err;
2358 }
2359
2360 static void tun_get_iff(struct net *net, struct tun_struct *tun,
2361 struct ifreq *ifr)
2362 {
2363 tun_debug(KERN_INFO, tun, "tun_get_iff\n");
2364
2365 strcpy(ifr->ifr_name, tun->dev->name);
2366
2367 ifr->ifr_flags = tun_flags(tun);
2368
2369 }
2370
2371 /* This is like a cut-down ethtool ops, except done via tun fd so no
2372 * privs required. */
2373 static int set_offload(struct tun_struct *tun, unsigned long arg)
2374 {
2375 netdev_features_t features = 0;
2376
2377 if (arg & TUN_F_CSUM) {
2378 features |= NETIF_F_HW_CSUM;
2379 arg &= ~TUN_F_CSUM;
2380
2381 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
2382 if (arg & TUN_F_TSO_ECN) {
2383 features |= NETIF_F_TSO_ECN;
2384 arg &= ~TUN_F_TSO_ECN;
2385 }
2386 if (arg & TUN_F_TSO4)
2387 features |= NETIF_F_TSO;
2388 if (arg & TUN_F_TSO6)
2389 features |= NETIF_F_TSO6;
2390 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
2391 }
2392
2393 arg &= ~TUN_F_UFO;
2394 }
2395
2396 /* This gives the user a way to test for new features in future by
2397 * trying to set them. */
2398 if (arg)
2399 return -EINVAL;
2400
2401 tun->set_features = features;
2402 tun->dev->wanted_features &= ~TUN_USER_FEATURES;
2403 tun->dev->wanted_features |= features;
2404 netdev_update_features(tun->dev);
2405
2406 return 0;
2407 }
2408
2409 static void tun_detach_filter(struct tun_struct *tun, int n)
2410 {
2411 int i;
2412 struct tun_file *tfile;
2413
2414 for (i = 0; i < n; i++) {
2415 tfile = rtnl_dereference(tun->tfiles[i]);
2416 lock_sock(tfile->socket.sk);
2417 sk_detach_filter(tfile->socket.sk);
2418 release_sock(tfile->socket.sk);
2419 }
2420
2421 tun->filter_attached = false;
2422 }
2423
2424 static int tun_attach_filter(struct tun_struct *tun)
2425 {
2426 int i, ret = 0;
2427 struct tun_file *tfile;
2428
2429 for (i = 0; i < tun->numqueues; i++) {
2430 tfile = rtnl_dereference(tun->tfiles[i]);
2431 lock_sock(tfile->socket.sk);
2432 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
2433 release_sock(tfile->socket.sk);
2434 if (ret) {
2435 tun_detach_filter(tun, i);
2436 return ret;
2437 }
2438 }
2439
2440 tun->filter_attached = true;
2441 return ret;
2442 }
2443
2444 static void tun_set_sndbuf(struct tun_struct *tun)
2445 {
2446 struct tun_file *tfile;
2447 int i;
2448
2449 for (i = 0; i < tun->numqueues; i++) {
2450 tfile = rtnl_dereference(tun->tfiles[i]);
2451 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
2452 }
2453 }
2454
2455 static int tun_set_queue(struct file *file, struct ifreq *ifr)
2456 {
2457 struct tun_file *tfile = file->private_data;
2458 struct tun_struct *tun;
2459 int ret = 0;
2460
2461 rtnl_lock();
2462
2463 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
2464 tun = tfile->detached;
2465 if (!tun) {
2466 ret = -EINVAL;
2467 goto unlock;
2468 }
2469 ret = security_tun_dev_attach_queue(tun->security);
2470 if (ret < 0)
2471 goto unlock;
2472 ret = tun_attach(tun, file, false, tun->flags & IFF_NAPI);
2473 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
2474 tun = rtnl_dereference(tfile->tun);
2475 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
2476 ret = -EINVAL;
2477 else
2478 __tun_detach(tfile, false);
2479 } else
2480 ret = -EINVAL;
2481
2482 unlock:
2483 rtnl_unlock();
2484 return ret;
2485 }
2486
2487 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
2488 unsigned long arg, int ifreq_len)
2489 {
2490 struct tun_file *tfile = file->private_data;
2491 struct tun_struct *tun;
2492 void __user* argp = (void __user*)arg;
2493 struct ifreq ifr;
2494 kuid_t owner;
2495 kgid_t group;
2496 int sndbuf;
2497 int vnet_hdr_sz;
2498 unsigned int ifindex;
2499 int le;
2500 int ret;
2501
2502 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == SOCK_IOC_TYPE) {
2503 if (copy_from_user(&ifr, argp, ifreq_len))
2504 return -EFAULT;
2505 } else {
2506 memset(&ifr, 0, sizeof(ifr));
2507 }
2508 if (cmd == TUNGETFEATURES) {
2509 /* Currently this just means: "what IFF flags are valid?".
2510 * This is needed because we never checked for invalid flags on
2511 * TUNSETIFF.
2512 */
2513 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
2514 (unsigned int __user*)argp);
2515 } else if (cmd == TUNSETQUEUE)
2516 return tun_set_queue(file, &ifr);
2517
2518 ret = 0;
2519 rtnl_lock();
2520
2521 tun = tun_get(tfile);
2522 if (cmd == TUNSETIFF) {
2523 ret = -EEXIST;
2524 if (tun)
2525 goto unlock;
2526
2527 ifr.ifr_name[IFNAMSIZ-1] = '\0';
2528
2529 ret = tun_set_iff(sock_net(&tfile->sk), file, &ifr);
2530
2531 if (ret)
2532 goto unlock;
2533
2534 if (copy_to_user(argp, &ifr, ifreq_len))
2535 ret = -EFAULT;
2536 goto unlock;
2537 }
2538 if (cmd == TUNSETIFINDEX) {
2539 ret = -EPERM;
2540 if (tun)
2541 goto unlock;
2542
2543 ret = -EFAULT;
2544 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
2545 goto unlock;
2546
2547 ret = 0;
2548 tfile->ifindex = ifindex;
2549 goto unlock;
2550 }
2551
2552 ret = -EBADFD;
2553 if (!tun)
2554 goto unlock;
2555
2556 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
2557
2558 ret = 0;
2559 switch (cmd) {
2560 case TUNGETIFF:
2561 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2562
2563 if (tfile->detached)
2564 ifr.ifr_flags |= IFF_DETACH_QUEUE;
2565 if (!tfile->socket.sk->sk_filter)
2566 ifr.ifr_flags |= IFF_NOFILTER;
2567
2568 if (copy_to_user(argp, &ifr, ifreq_len))
2569 ret = -EFAULT;
2570 break;
2571
2572 case TUNSETNOCSUM:
2573 /* Disable/Enable checksum */
2574
2575 /* [unimplemented] */
2576 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
2577 arg ? "disabled" : "enabled");
2578 break;
2579
2580 case TUNSETPERSIST:
2581 /* Disable/Enable persist mode. Keep an extra reference to the
2582 * module to prevent the module being unprobed.
2583 */
2584 if (arg && !(tun->flags & IFF_PERSIST)) {
2585 tun->flags |= IFF_PERSIST;
2586 __module_get(THIS_MODULE);
2587 }
2588 if (!arg && (tun->flags & IFF_PERSIST)) {
2589 tun->flags &= ~IFF_PERSIST;
2590 module_put(THIS_MODULE);
2591 }
2592
2593 tun_debug(KERN_INFO, tun, "persist %s\n",
2594 arg ? "enabled" : "disabled");
2595 break;
2596
2597 case TUNSETOWNER:
2598 /* Set owner of the device */
2599 owner = make_kuid(current_user_ns(), arg);
2600 if (!uid_valid(owner)) {
2601 ret = -EINVAL;
2602 break;
2603 }
2604 tun->owner = owner;
2605 tun_debug(KERN_INFO, tun, "owner set to %u\n",
2606 from_kuid(&init_user_ns, tun->owner));
2607 break;
2608
2609 case TUNSETGROUP:
2610 /* Set group of the device */
2611 group = make_kgid(current_user_ns(), arg);
2612 if (!gid_valid(group)) {
2613 ret = -EINVAL;
2614 break;
2615 }
2616 tun->group = group;
2617 tun_debug(KERN_INFO, tun, "group set to %u\n",
2618 from_kgid(&init_user_ns, tun->group));
2619 break;
2620
2621 case TUNSETLINK:
2622 /* Only allow setting the type when the interface is down */
2623 if (tun->dev->flags & IFF_UP) {
2624 tun_debug(KERN_INFO, tun,
2625 "Linktype set failed because interface is up\n");
2626 ret = -EBUSY;
2627 } else {
2628 tun->dev->type = (int) arg;
2629 tun_debug(KERN_INFO, tun, "linktype set to %d\n",
2630 tun->dev->type);
2631 ret = 0;
2632 }
2633 break;
2634
2635 #ifdef TUN_DEBUG
2636 case TUNSETDEBUG:
2637 tun->debug = arg;
2638 break;
2639 #endif
2640 case TUNSETOFFLOAD:
2641 ret = set_offload(tun, arg);
2642 break;
2643
2644 case TUNSETTXFILTER:
2645 /* Can be set only for TAPs */
2646 ret = -EINVAL;
2647 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2648 break;
2649 ret = update_filter(&tun->txflt, (void __user *)arg);
2650 break;
2651
2652 case SIOCGIFHWADDR:
2653 /* Get hw address */
2654 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
2655 ifr.ifr_hwaddr.sa_family = tun->dev->type;
2656 if (copy_to_user(argp, &ifr, ifreq_len))
2657 ret = -EFAULT;
2658 break;
2659
2660 case SIOCSIFHWADDR:
2661 /* Set hw address */
2662 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
2663 ifr.ifr_hwaddr.sa_data);
2664
2665 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
2666 break;
2667
2668 case TUNGETSNDBUF:
2669 sndbuf = tfile->socket.sk->sk_sndbuf;
2670 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
2671 ret = -EFAULT;
2672 break;
2673
2674 case TUNSETSNDBUF:
2675 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
2676 ret = -EFAULT;
2677 break;
2678 }
2679 if (sndbuf <= 0) {
2680 ret = -EINVAL;
2681 break;
2682 }
2683
2684 tun->sndbuf = sndbuf;
2685 tun_set_sndbuf(tun);
2686 break;
2687
2688 case TUNGETVNETHDRSZ:
2689 vnet_hdr_sz = tun->vnet_hdr_sz;
2690 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
2691 ret = -EFAULT;
2692 break;
2693
2694 case TUNSETVNETHDRSZ:
2695 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
2696 ret = -EFAULT;
2697 break;
2698 }
2699 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
2700 ret = -EINVAL;
2701 break;
2702 }
2703
2704 tun->vnet_hdr_sz = vnet_hdr_sz;
2705 break;
2706
2707 case TUNGETVNETLE:
2708 le = !!(tun->flags & TUN_VNET_LE);
2709 if (put_user(le, (int __user *)argp))
2710 ret = -EFAULT;
2711 break;
2712
2713 case TUNSETVNETLE:
2714 if (get_user(le, (int __user *)argp)) {
2715 ret = -EFAULT;
2716 break;
2717 }
2718 if (le)
2719 tun->flags |= TUN_VNET_LE;
2720 else
2721 tun->flags &= ~TUN_VNET_LE;
2722 break;
2723
2724 case TUNGETVNETBE:
2725 ret = tun_get_vnet_be(tun, argp);
2726 break;
2727
2728 case TUNSETVNETBE:
2729 ret = tun_set_vnet_be(tun, argp);
2730 break;
2731
2732 case TUNATTACHFILTER:
2733 /* Can be set only for TAPs */
2734 ret = -EINVAL;
2735 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2736 break;
2737 ret = -EFAULT;
2738 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
2739 break;
2740
2741 ret = tun_attach_filter(tun);
2742 break;
2743
2744 case TUNDETACHFILTER:
2745 /* Can be set only for TAPs */
2746 ret = -EINVAL;
2747 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2748 break;
2749 ret = 0;
2750 tun_detach_filter(tun, tun->numqueues);
2751 break;
2752
2753 case TUNGETFILTER:
2754 ret = -EINVAL;
2755 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2756 break;
2757 ret = -EFAULT;
2758 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
2759 break;
2760 ret = 0;
2761 break;
2762
2763 default:
2764 ret = -EINVAL;
2765 break;
2766 }
2767
2768 unlock:
2769 rtnl_unlock();
2770 if (tun)
2771 tun_put(tun);
2772 return ret;
2773 }
2774
2775 static long tun_chr_ioctl(struct file *file,
2776 unsigned int cmd, unsigned long arg)
2777 {
2778 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
2779 }
2780
2781 #ifdef CONFIG_COMPAT
2782 static long tun_chr_compat_ioctl(struct file *file,
2783 unsigned int cmd, unsigned long arg)
2784 {
2785 switch (cmd) {
2786 case TUNSETIFF:
2787 case TUNGETIFF:
2788 case TUNSETTXFILTER:
2789 case TUNGETSNDBUF:
2790 case TUNSETSNDBUF:
2791 case SIOCGIFHWADDR:
2792 case SIOCSIFHWADDR:
2793 arg = (unsigned long)compat_ptr(arg);
2794 break;
2795 default:
2796 arg = (compat_ulong_t)arg;
2797 break;
2798 }
2799
2800 /*
2801 * compat_ifreq is shorter than ifreq, so we must not access beyond
2802 * the end of that structure. All fields that are used in this
2803 * driver are compatible though, we don't need to convert the
2804 * contents.
2805 */
2806 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
2807 }
2808 #endif /* CONFIG_COMPAT */
2809
2810 static int tun_chr_fasync(int fd, struct file *file, int on)
2811 {
2812 struct tun_file *tfile = file->private_data;
2813 int ret;
2814
2815 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
2816 goto out;
2817
2818 if (on) {
2819 __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
2820 tfile->flags |= TUN_FASYNC;
2821 } else
2822 tfile->flags &= ~TUN_FASYNC;
2823 ret = 0;
2824 out:
2825 return ret;
2826 }
2827
2828 static int tun_chr_open(struct inode *inode, struct file * file)
2829 {
2830 struct net *net = current->nsproxy->net_ns;
2831 struct tun_file *tfile;
2832
2833 DBG1(KERN_INFO, "tunX: tun_chr_open\n");
2834
2835 tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
2836 &tun_proto, 0);
2837 if (!tfile)
2838 return -ENOMEM;
2839 RCU_INIT_POINTER(tfile->tun, NULL);
2840 tfile->flags = 0;
2841 tfile->ifindex = 0;
2842
2843 init_waitqueue_head(&tfile->wq.wait);
2844 RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq);
2845
2846 tfile->socket.file = file;
2847 tfile->socket.ops = &tun_socket_ops;
2848
2849 sock_init_data(&tfile->socket, &tfile->sk);
2850
2851 tfile->sk.sk_write_space = tun_sock_write_space;
2852 tfile->sk.sk_sndbuf = INT_MAX;
2853
2854 file->private_data = tfile;
2855 INIT_LIST_HEAD(&tfile->next);
2856
2857 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
2858
2859 memset(&tfile->tx_array, 0, sizeof(tfile->tx_array));
2860
2861 return 0;
2862 }
2863
2864 static int tun_chr_close(struct inode *inode, struct file *file)
2865 {
2866 struct tun_file *tfile = file->private_data;
2867
2868 tun_detach(tfile, true);
2869
2870 return 0;
2871 }
2872
2873 #ifdef CONFIG_PROC_FS
2874 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *file)
2875 {
2876 struct tun_file *tfile = file->private_data;
2877 struct tun_struct *tun;
2878 struct ifreq ifr;
2879
2880 memset(&ifr, 0, sizeof(ifr));
2881
2882 rtnl_lock();
2883 tun = tun_get(tfile);
2884 if (tun)
2885 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2886 rtnl_unlock();
2887
2888 if (tun)
2889 tun_put(tun);
2890
2891 seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
2892 }
2893 #endif
2894
2895 static const struct file_operations tun_fops = {
2896 .owner = THIS_MODULE,
2897 .llseek = no_llseek,
2898 .read_iter = tun_chr_read_iter,
2899 .write_iter = tun_chr_write_iter,
2900 .poll = tun_chr_poll,
2901 .unlocked_ioctl = tun_chr_ioctl,
2902 #ifdef CONFIG_COMPAT
2903 .compat_ioctl = tun_chr_compat_ioctl,
2904 #endif
2905 .open = tun_chr_open,
2906 .release = tun_chr_close,
2907 .fasync = tun_chr_fasync,
2908 #ifdef CONFIG_PROC_FS
2909 .show_fdinfo = tun_chr_show_fdinfo,
2910 #endif
2911 };
2912
2913 static struct miscdevice tun_miscdev = {
2914 .minor = TUN_MINOR,
2915 .name = "tun",
2916 .nodename = "net/tun",
2917 .fops = &tun_fops,
2918 };
2919
2920 /* ethtool interface */
2921
2922 static int tun_get_link_ksettings(struct net_device *dev,
2923 struct ethtool_link_ksettings *cmd)
2924 {
2925 ethtool_link_ksettings_zero_link_mode(cmd, supported);
2926 ethtool_link_ksettings_zero_link_mode(cmd, advertising);
2927 cmd->base.speed = SPEED_10;
2928 cmd->base.duplex = DUPLEX_FULL;
2929 cmd->base.port = PORT_TP;
2930 cmd->base.phy_address = 0;
2931 cmd->base.autoneg = AUTONEG_DISABLE;
2932 return 0;
2933 }
2934
2935 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
2936 {
2937 struct tun_struct *tun = netdev_priv(dev);
2938
2939 strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
2940 strlcpy(info->version, DRV_VERSION, sizeof(info->version));
2941
2942 switch (tun->flags & TUN_TYPE_MASK) {
2943 case IFF_TUN:
2944 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
2945 break;
2946 case IFF_TAP:
2947 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
2948 break;
2949 }
2950 }
2951
2952 static u32 tun_get_msglevel(struct net_device *dev)
2953 {
2954 #ifdef TUN_DEBUG
2955 struct tun_struct *tun = netdev_priv(dev);
2956 return tun->debug;
2957 #else
2958 return -EOPNOTSUPP;
2959 #endif
2960 }
2961
2962 static void tun_set_msglevel(struct net_device *dev, u32 value)
2963 {
2964 #ifdef TUN_DEBUG
2965 struct tun_struct *tun = netdev_priv(dev);
2966 tun->debug = value;
2967 #endif
2968 }
2969
2970 static int tun_get_coalesce(struct net_device *dev,
2971 struct ethtool_coalesce *ec)
2972 {
2973 struct tun_struct *tun = netdev_priv(dev);
2974
2975 ec->rx_max_coalesced_frames = tun->rx_batched;
2976
2977 return 0;
2978 }
2979
2980 static int tun_set_coalesce(struct net_device *dev,
2981 struct ethtool_coalesce *ec)
2982 {
2983 struct tun_struct *tun = netdev_priv(dev);
2984
2985 if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT)
2986 tun->rx_batched = NAPI_POLL_WEIGHT;
2987 else
2988 tun->rx_batched = ec->rx_max_coalesced_frames;
2989
2990 return 0;
2991 }
2992
2993 static const struct ethtool_ops tun_ethtool_ops = {
2994 .get_drvinfo = tun_get_drvinfo,
2995 .get_msglevel = tun_get_msglevel,
2996 .set_msglevel = tun_set_msglevel,
2997 .get_link = ethtool_op_get_link,
2998 .get_ts_info = ethtool_op_get_ts_info,
2999 .get_coalesce = tun_get_coalesce,
3000 .set_coalesce = tun_set_coalesce,
3001 .get_link_ksettings = tun_get_link_ksettings,
3002 };
3003
3004 static int tun_queue_resize(struct tun_struct *tun)
3005 {
3006 struct net_device *dev = tun->dev;
3007 struct tun_file *tfile;
3008 struct skb_array **arrays;
3009 int n = tun->numqueues + tun->numdisabled;
3010 int ret, i;
3011
3012 arrays = kmalloc_array(n, sizeof(*arrays), GFP_KERNEL);
3013 if (!arrays)
3014 return -ENOMEM;
3015
3016 for (i = 0; i < tun->numqueues; i++) {
3017 tfile = rtnl_dereference(tun->tfiles[i]);
3018 arrays[i] = &tfile->tx_array;
3019 }
3020 list_for_each_entry(tfile, &tun->disabled, next)
3021 arrays[i++] = &tfile->tx_array;
3022
3023 ret = skb_array_resize_multiple(arrays, n,
3024 dev->tx_queue_len, GFP_KERNEL);
3025
3026 kfree(arrays);
3027 return ret;
3028 }
3029
3030 static int tun_device_event(struct notifier_block *unused,
3031 unsigned long event, void *ptr)
3032 {
3033 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3034 struct tun_struct *tun = netdev_priv(dev);
3035
3036 if (dev->rtnl_link_ops != &tun_link_ops)
3037 return NOTIFY_DONE;
3038
3039 switch (event) {
3040 case NETDEV_CHANGE_TX_QUEUE_LEN:
3041 if (tun_queue_resize(tun))
3042 return NOTIFY_BAD;
3043 break;
3044 default:
3045 break;
3046 }
3047
3048 return NOTIFY_DONE;
3049 }
3050
3051 static struct notifier_block tun_notifier_block __read_mostly = {
3052 .notifier_call = tun_device_event,
3053 };
3054
3055 static int __init tun_init(void)
3056 {
3057 int ret = 0;
3058
3059 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
3060
3061 ret = rtnl_link_register(&tun_link_ops);
3062 if (ret) {
3063 pr_err("Can't register link_ops\n");
3064 goto err_linkops;
3065 }
3066
3067 ret = misc_register(&tun_miscdev);
3068 if (ret) {
3069 pr_err("Can't register misc device %d\n", TUN_MINOR);
3070 goto err_misc;
3071 }
3072
3073 ret = register_netdevice_notifier(&tun_notifier_block);
3074 if (ret) {
3075 pr_err("Can't register netdevice notifier\n");
3076 goto err_notifier;
3077 }
3078
3079 return 0;
3080
3081 err_notifier:
3082 misc_deregister(&tun_miscdev);
3083 err_misc:
3084 rtnl_link_unregister(&tun_link_ops);
3085 err_linkops:
3086 return ret;
3087 }
3088
3089 static void tun_cleanup(void)
3090 {
3091 misc_deregister(&tun_miscdev);
3092 rtnl_link_unregister(&tun_link_ops);
3093 unregister_netdevice_notifier(&tun_notifier_block);
3094 }
3095
3096 /* Get an underlying socket object from tun file. Returns error unless file is
3097 * attached to a device. The returned object works like a packet socket, it
3098 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
3099 * holding a reference to the file for as long as the socket is in use. */
3100 struct socket *tun_get_socket(struct file *file)
3101 {
3102 struct tun_file *tfile;
3103 if (file->f_op != &tun_fops)
3104 return ERR_PTR(-EINVAL);
3105 tfile = file->private_data;
3106 if (!tfile)
3107 return ERR_PTR(-EBADFD);
3108 return &tfile->socket;
3109 }
3110 EXPORT_SYMBOL_GPL(tun_get_socket);
3111
3112 struct skb_array *tun_get_skb_array(struct file *file)
3113 {
3114 struct tun_file *tfile;
3115
3116 if (file->f_op != &tun_fops)
3117 return ERR_PTR(-EINVAL);
3118 tfile = file->private_data;
3119 if (!tfile)
3120 return ERR_PTR(-EBADFD);
3121 return &tfile->tx_array;
3122 }
3123 EXPORT_SYMBOL_GPL(tun_get_skb_array);
3124
3125 module_init(tun_init);
3126 module_exit(tun_cleanup);
3127 MODULE_DESCRIPTION(DRV_DESCRIPTION);
3128 MODULE_AUTHOR(DRV_COPYRIGHT);
3129 MODULE_LICENSE("GPL");
3130 MODULE_ALIAS_MISCDEV(TUN_MINOR);
3131 MODULE_ALIAS("devname:net/tun");
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