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[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(unsigned long data)
448 {
449 struct tun_struct *tun = (struct tun_struct *)data;
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_detach(struct tun_file *tfile, bool clean)
615 {
616 struct tun_file *ntfile;
617 struct tun_struct *tun;
618
619 tun = rtnl_dereference(tfile->tun);
620
621 if (tun && clean) {
622 tun_napi_disable(tun, tfile);
623 tun_napi_del(tun, tfile);
624 }
625
626 if (tun && !tfile->detached) {
627 u16 index = tfile->queue_index;
628 BUG_ON(index >= tun->numqueues);
629
630 rcu_assign_pointer(tun->tfiles[index],
631 tun->tfiles[tun->numqueues - 1]);
632 ntfile = rtnl_dereference(tun->tfiles[index]);
633 ntfile->queue_index = index;
634
635 --tun->numqueues;
636 if (clean) {
637 RCU_INIT_POINTER(tfile->tun, NULL);
638 sock_put(&tfile->sk);
639 } else
640 tun_disable_queue(tun, tfile);
641
642 synchronize_net();
643 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
644 /* Drop read queue */
645 tun_queue_purge(tfile);
646 tun_set_real_num_queues(tun);
647 } else if (tfile->detached && clean) {
648 tun = tun_enable_queue(tfile);
649 sock_put(&tfile->sk);
650 }
651
652 if (clean) {
653 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
654 netif_carrier_off(tun->dev);
655
656 if (!(tun->flags & IFF_PERSIST) &&
657 tun->dev->reg_state == NETREG_REGISTERED)
658 unregister_netdevice(tun->dev);
659 }
660 if (tun)
661 skb_array_cleanup(&tfile->tx_array);
662 sock_put(&tfile->sk);
663 }
664 }
665
666 static void tun_detach(struct tun_file *tfile, bool clean)
667 {
668 rtnl_lock();
669 __tun_detach(tfile, clean);
670 rtnl_unlock();
671 }
672
673 static void tun_detach_all(struct net_device *dev)
674 {
675 struct tun_struct *tun = netdev_priv(dev);
676 struct bpf_prog *xdp_prog = rtnl_dereference(tun->xdp_prog);
677 struct tun_file *tfile, *tmp;
678 int i, n = tun->numqueues;
679
680 for (i = 0; i < n; i++) {
681 tfile = rtnl_dereference(tun->tfiles[i]);
682 BUG_ON(!tfile);
683 tun_napi_disable(tun, tfile);
684 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
685 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
686 RCU_INIT_POINTER(tfile->tun, NULL);
687 --tun->numqueues;
688 }
689 list_for_each_entry(tfile, &tun->disabled, next) {
690 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
691 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
692 RCU_INIT_POINTER(tfile->tun, NULL);
693 }
694 BUG_ON(tun->numqueues != 0);
695
696 synchronize_net();
697 for (i = 0; i < n; i++) {
698 tfile = rtnl_dereference(tun->tfiles[i]);
699 tun_napi_del(tun, tfile);
700 /* Drop read queue */
701 tun_queue_purge(tfile);
702 sock_put(&tfile->sk);
703 }
704 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
705 tun_enable_queue(tfile);
706 tun_queue_purge(tfile);
707 sock_put(&tfile->sk);
708 }
709 BUG_ON(tun->numdisabled != 0);
710
711 if (xdp_prog)
712 bpf_prog_put(xdp_prog);
713
714 if (tun->flags & IFF_PERSIST)
715 module_put(THIS_MODULE);
716 }
717
718 static int tun_attach(struct tun_struct *tun, struct file *file,
719 bool skip_filter, bool napi)
720 {
721 struct tun_file *tfile = file->private_data;
722 struct net_device *dev = tun->dev;
723 int err;
724
725 err = security_tun_dev_attach(tfile->socket.sk, tun->security);
726 if (err < 0)
727 goto out;
728
729 err = -EINVAL;
730 if (rtnl_dereference(tfile->tun) && !tfile->detached)
731 goto out;
732
733 err = -EBUSY;
734 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
735 goto out;
736
737 err = -E2BIG;
738 if (!tfile->detached &&
739 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
740 goto out;
741
742 err = 0;
743
744 /* Re-attach the filter to persist device */
745 if (!skip_filter && (tun->filter_attached == true)) {
746 lock_sock(tfile->socket.sk);
747 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
748 release_sock(tfile->socket.sk);
749 if (!err)
750 goto out;
751 }
752
753 if (!tfile->detached &&
754 skb_array_init(&tfile->tx_array, dev->tx_queue_len, GFP_KERNEL)) {
755 err = -ENOMEM;
756 goto out;
757 }
758
759 tfile->queue_index = tun->numqueues;
760 tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
761 rcu_assign_pointer(tfile->tun, tun);
762 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
763 tun->numqueues++;
764
765 if (tfile->detached) {
766 tun_enable_queue(tfile);
767 } else {
768 sock_hold(&tfile->sk);
769 tun_napi_init(tun, tfile, napi);
770 }
771
772 tun_set_real_num_queues(tun);
773
774 /* device is allowed to go away first, so no need to hold extra
775 * refcnt.
776 */
777
778 out:
779 return err;
780 }
781
782 static struct tun_struct *tun_get(struct tun_file *tfile)
783 {
784 struct tun_struct *tun;
785
786 rcu_read_lock();
787 tun = rcu_dereference(tfile->tun);
788 if (tun)
789 dev_hold(tun->dev);
790 rcu_read_unlock();
791
792 return tun;
793 }
794
795 static void tun_put(struct tun_struct *tun)
796 {
797 dev_put(tun->dev);
798 }
799
800 /* TAP filtering */
801 static void addr_hash_set(u32 *mask, const u8 *addr)
802 {
803 int n = ether_crc(ETH_ALEN, addr) >> 26;
804 mask[n >> 5] |= (1 << (n & 31));
805 }
806
807 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
808 {
809 int n = ether_crc(ETH_ALEN, addr) >> 26;
810 return mask[n >> 5] & (1 << (n & 31));
811 }
812
813 static int update_filter(struct tap_filter *filter, void __user *arg)
814 {
815 struct { u8 u[ETH_ALEN]; } *addr;
816 struct tun_filter uf;
817 int err, alen, n, nexact;
818
819 if (copy_from_user(&uf, arg, sizeof(uf)))
820 return -EFAULT;
821
822 if (!uf.count) {
823 /* Disabled */
824 filter->count = 0;
825 return 0;
826 }
827
828 alen = ETH_ALEN * uf.count;
829 addr = memdup_user(arg + sizeof(uf), alen);
830 if (IS_ERR(addr))
831 return PTR_ERR(addr);
832
833 /* The filter is updated without holding any locks. Which is
834 * perfectly safe. We disable it first and in the worst
835 * case we'll accept a few undesired packets. */
836 filter->count = 0;
837 wmb();
838
839 /* Use first set of addresses as an exact filter */
840 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
841 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
842
843 nexact = n;
844
845 /* Remaining multicast addresses are hashed,
846 * unicast will leave the filter disabled. */
847 memset(filter->mask, 0, sizeof(filter->mask));
848 for (; n < uf.count; n++) {
849 if (!is_multicast_ether_addr(addr[n].u)) {
850 err = 0; /* no filter */
851 goto free_addr;
852 }
853 addr_hash_set(filter->mask, addr[n].u);
854 }
855
856 /* For ALLMULTI just set the mask to all ones.
857 * This overrides the mask populated above. */
858 if ((uf.flags & TUN_FLT_ALLMULTI))
859 memset(filter->mask, ~0, sizeof(filter->mask));
860
861 /* Now enable the filter */
862 wmb();
863 filter->count = nexact;
864
865 /* Return the number of exact filters */
866 err = nexact;
867 free_addr:
868 kfree(addr);
869 return err;
870 }
871
872 /* Returns: 0 - drop, !=0 - accept */
873 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
874 {
875 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
876 * at this point. */
877 struct ethhdr *eh = (struct ethhdr *) skb->data;
878 int i;
879
880 /* Exact match */
881 for (i = 0; i < filter->count; i++)
882 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
883 return 1;
884
885 /* Inexact match (multicast only) */
886 if (is_multicast_ether_addr(eh->h_dest))
887 return addr_hash_test(filter->mask, eh->h_dest);
888
889 return 0;
890 }
891
892 /*
893 * Checks whether the packet is accepted or not.
894 * Returns: 0 - drop, !=0 - accept
895 */
896 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
897 {
898 if (!filter->count)
899 return 1;
900
901 return run_filter(filter, skb);
902 }
903
904 /* Network device part of the driver */
905
906 static const struct ethtool_ops tun_ethtool_ops;
907
908 /* Net device detach from fd. */
909 static void tun_net_uninit(struct net_device *dev)
910 {
911 tun_detach_all(dev);
912 }
913
914 /* Net device open. */
915 static int tun_net_open(struct net_device *dev)
916 {
917 struct tun_struct *tun = netdev_priv(dev);
918 int i;
919
920 netif_tx_start_all_queues(dev);
921
922 for (i = 0; i < tun->numqueues; i++) {
923 struct tun_file *tfile;
924
925 tfile = rtnl_dereference(tun->tfiles[i]);
926 tfile->socket.sk->sk_write_space(tfile->socket.sk);
927 }
928
929 return 0;
930 }
931
932 /* Net device close. */
933 static int tun_net_close(struct net_device *dev)
934 {
935 netif_tx_stop_all_queues(dev);
936 return 0;
937 }
938
939 /* Net device start xmit */
940 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
941 {
942 struct tun_struct *tun = netdev_priv(dev);
943 int txq = skb->queue_mapping;
944 struct tun_file *tfile;
945 u32 numqueues = 0;
946
947 rcu_read_lock();
948 tfile = rcu_dereference(tun->tfiles[txq]);
949 numqueues = READ_ONCE(tun->numqueues);
950
951 /* Drop packet if interface is not attached */
952 if (txq >= numqueues)
953 goto drop;
954
955 #ifdef CONFIG_RPS
956 if (numqueues == 1 && static_key_false(&rps_needed)) {
957 /* Select queue was not called for the skbuff, so we extract the
958 * RPS hash and save it into the flow_table here.
959 */
960 __u32 rxhash;
961
962 rxhash = __skb_get_hash_symmetric(skb);
963 if (rxhash) {
964 struct tun_flow_entry *e;
965 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)],
966 rxhash);
967 if (e)
968 tun_flow_save_rps_rxhash(e, rxhash);
969 }
970 }
971 #endif
972
973 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
974
975 BUG_ON(!tfile);
976
977 /* Drop if the filter does not like it.
978 * This is a noop if the filter is disabled.
979 * Filter can be enabled only for the TAP devices. */
980 if (!check_filter(&tun->txflt, skb))
981 goto drop;
982
983 if (tfile->socket.sk->sk_filter &&
984 sk_filter(tfile->socket.sk, skb))
985 goto drop;
986
987 if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC)))
988 goto drop;
989
990 skb_tx_timestamp(skb);
991
992 /* Orphan the skb - required as we might hang on to it
993 * for indefinite time.
994 */
995 skb_orphan(skb);
996
997 nf_reset(skb);
998
999 if (skb_array_produce(&tfile->tx_array, skb))
1000 goto drop;
1001
1002 /* Notify and wake up reader process */
1003 if (tfile->flags & TUN_FASYNC)
1004 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1005 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1006
1007 rcu_read_unlock();
1008 return NETDEV_TX_OK;
1009
1010 drop:
1011 this_cpu_inc(tun->pcpu_stats->tx_dropped);
1012 skb_tx_error(skb);
1013 kfree_skb(skb);
1014 rcu_read_unlock();
1015 return NET_XMIT_DROP;
1016 }
1017
1018 static void tun_net_mclist(struct net_device *dev)
1019 {
1020 /*
1021 * This callback is supposed to deal with mc filter in
1022 * _rx_ path and has nothing to do with the _tx_ path.
1023 * In rx path we always accept everything userspace gives us.
1024 */
1025 }
1026
1027 static netdev_features_t tun_net_fix_features(struct net_device *dev,
1028 netdev_features_t features)
1029 {
1030 struct tun_struct *tun = netdev_priv(dev);
1031
1032 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
1033 }
1034 #ifdef CONFIG_NET_POLL_CONTROLLER
1035 static void tun_poll_controller(struct net_device *dev)
1036 {
1037 /*
1038 * Tun only receives frames when:
1039 * 1) the char device endpoint gets data from user space
1040 * 2) the tun socket gets a sendmsg call from user space
1041 * If NAPI is not enabled, since both of those are synchronous
1042 * operations, we are guaranteed never to have pending data when we poll
1043 * for it so there is nothing to do here but return.
1044 * We need this though so netpoll recognizes us as an interface that
1045 * supports polling, which enables bridge devices in virt setups to
1046 * still use netconsole
1047 * If NAPI is enabled, however, we need to schedule polling for all
1048 * queues unless we are using napi_gro_frags(), which we call in
1049 * process context and not in NAPI context.
1050 */
1051 struct tun_struct *tun = netdev_priv(dev);
1052
1053 if (tun->flags & IFF_NAPI) {
1054 struct tun_file *tfile;
1055 int i;
1056
1057 if (tun_napi_frags_enabled(tun))
1058 return;
1059
1060 rcu_read_lock();
1061 for (i = 0; i < tun->numqueues; i++) {
1062 tfile = rcu_dereference(tun->tfiles[i]);
1063 if (tfile->napi_enabled)
1064 napi_schedule(&tfile->napi);
1065 }
1066 rcu_read_unlock();
1067 }
1068 return;
1069 }
1070 #endif
1071
1072 static void tun_set_headroom(struct net_device *dev, int new_hr)
1073 {
1074 struct tun_struct *tun = netdev_priv(dev);
1075
1076 if (new_hr < NET_SKB_PAD)
1077 new_hr = NET_SKB_PAD;
1078
1079 tun->align = new_hr;
1080 }
1081
1082 static void
1083 tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
1084 {
1085 u32 rx_dropped = 0, tx_dropped = 0, rx_frame_errors = 0;
1086 struct tun_struct *tun = netdev_priv(dev);
1087 struct tun_pcpu_stats *p;
1088 int i;
1089
1090 for_each_possible_cpu(i) {
1091 u64 rxpackets, rxbytes, txpackets, txbytes;
1092 unsigned int start;
1093
1094 p = per_cpu_ptr(tun->pcpu_stats, i);
1095 do {
1096 start = u64_stats_fetch_begin(&p->syncp);
1097 rxpackets = p->rx_packets;
1098 rxbytes = p->rx_bytes;
1099 txpackets = p->tx_packets;
1100 txbytes = p->tx_bytes;
1101 } while (u64_stats_fetch_retry(&p->syncp, start));
1102
1103 stats->rx_packets += rxpackets;
1104 stats->rx_bytes += rxbytes;
1105 stats->tx_packets += txpackets;
1106 stats->tx_bytes += txbytes;
1107
1108 /* u32 counters */
1109 rx_dropped += p->rx_dropped;
1110 rx_frame_errors += p->rx_frame_errors;
1111 tx_dropped += p->tx_dropped;
1112 }
1113 stats->rx_dropped = rx_dropped;
1114 stats->rx_frame_errors = rx_frame_errors;
1115 stats->tx_dropped = tx_dropped;
1116 }
1117
1118 static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1119 struct netlink_ext_ack *extack)
1120 {
1121 struct tun_struct *tun = netdev_priv(dev);
1122 struct bpf_prog *old_prog;
1123
1124 old_prog = rtnl_dereference(tun->xdp_prog);
1125 rcu_assign_pointer(tun->xdp_prog, prog);
1126 if (old_prog)
1127 bpf_prog_put(old_prog);
1128
1129 return 0;
1130 }
1131
1132 static u32 tun_xdp_query(struct net_device *dev)
1133 {
1134 struct tun_struct *tun = netdev_priv(dev);
1135 const struct bpf_prog *xdp_prog;
1136
1137 xdp_prog = rtnl_dereference(tun->xdp_prog);
1138 if (xdp_prog)
1139 return xdp_prog->aux->id;
1140
1141 return 0;
1142 }
1143
1144 static int tun_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1145 {
1146 switch (xdp->command) {
1147 case XDP_SETUP_PROG:
1148 return tun_xdp_set(dev, xdp->prog, xdp->extack);
1149 case XDP_QUERY_PROG:
1150 xdp->prog_id = tun_xdp_query(dev);
1151 xdp->prog_attached = !!xdp->prog_id;
1152 return 0;
1153 default:
1154 return -EINVAL;
1155 }
1156 }
1157
1158 static const struct net_device_ops tun_netdev_ops = {
1159 .ndo_uninit = tun_net_uninit,
1160 .ndo_open = tun_net_open,
1161 .ndo_stop = tun_net_close,
1162 .ndo_start_xmit = tun_net_xmit,
1163 .ndo_fix_features = tun_net_fix_features,
1164 .ndo_select_queue = tun_select_queue,
1165 #ifdef CONFIG_NET_POLL_CONTROLLER
1166 .ndo_poll_controller = tun_poll_controller,
1167 #endif
1168 .ndo_set_rx_headroom = tun_set_headroom,
1169 .ndo_get_stats64 = tun_net_get_stats64,
1170 };
1171
1172 static const struct net_device_ops tap_netdev_ops = {
1173 .ndo_uninit = tun_net_uninit,
1174 .ndo_open = tun_net_open,
1175 .ndo_stop = tun_net_close,
1176 .ndo_start_xmit = tun_net_xmit,
1177 .ndo_fix_features = tun_net_fix_features,
1178 .ndo_set_rx_mode = tun_net_mclist,
1179 .ndo_set_mac_address = eth_mac_addr,
1180 .ndo_validate_addr = eth_validate_addr,
1181 .ndo_select_queue = tun_select_queue,
1182 #ifdef CONFIG_NET_POLL_CONTROLLER
1183 .ndo_poll_controller = tun_poll_controller,
1184 #endif
1185 .ndo_features_check = passthru_features_check,
1186 .ndo_set_rx_headroom = tun_set_headroom,
1187 .ndo_get_stats64 = tun_net_get_stats64,
1188 .ndo_bpf = tun_xdp,
1189 };
1190
1191 static void tun_flow_init(struct tun_struct *tun)
1192 {
1193 int i;
1194
1195 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1196 INIT_HLIST_HEAD(&tun->flows[i]);
1197
1198 tun->ageing_time = TUN_FLOW_EXPIRE;
1199 setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun);
1200 }
1201
1202 static void tun_flow_uninit(struct tun_struct *tun)
1203 {
1204 del_timer_sync(&tun->flow_gc_timer);
1205 tun_flow_flush(tun);
1206 }
1207
1208 #define MIN_MTU 68
1209 #define MAX_MTU 65535
1210
1211 /* Initialize net device. */
1212 static void tun_net_init(struct net_device *dev)
1213 {
1214 struct tun_struct *tun = netdev_priv(dev);
1215
1216 switch (tun->flags & TUN_TYPE_MASK) {
1217 case IFF_TUN:
1218 dev->netdev_ops = &tun_netdev_ops;
1219
1220 /* Point-to-Point TUN Device */
1221 dev->hard_header_len = 0;
1222 dev->addr_len = 0;
1223 dev->mtu = 1500;
1224
1225 /* Zero header length */
1226 dev->type = ARPHRD_NONE;
1227 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1228 break;
1229
1230 case IFF_TAP:
1231 dev->netdev_ops = &tap_netdev_ops;
1232 /* Ethernet TAP Device */
1233 ether_setup(dev);
1234 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1235 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1236
1237 eth_hw_addr_random(dev);
1238
1239 break;
1240 }
1241
1242 dev->min_mtu = MIN_MTU;
1243 dev->max_mtu = MAX_MTU - dev->hard_header_len;
1244 }
1245
1246 /* Character device part */
1247
1248 /* Poll */
1249 static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
1250 {
1251 struct tun_file *tfile = file->private_data;
1252 struct tun_struct *tun = tun_get(tfile);
1253 struct sock *sk;
1254 unsigned int mask = 0;
1255
1256 if (!tun)
1257 return POLLERR;
1258
1259 sk = tfile->socket.sk;
1260
1261 tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
1262
1263 poll_wait(file, sk_sleep(sk), wait);
1264
1265 if (!skb_array_empty(&tfile->tx_array))
1266 mask |= POLLIN | POLLRDNORM;
1267
1268 if (tun->dev->flags & IFF_UP &&
1269 (sock_writeable(sk) ||
1270 (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1271 sock_writeable(sk))))
1272 mask |= POLLOUT | POLLWRNORM;
1273
1274 if (tun->dev->reg_state != NETREG_REGISTERED)
1275 mask = POLLERR;
1276
1277 tun_put(tun);
1278 return mask;
1279 }
1280
1281 static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile,
1282 size_t len,
1283 const struct iov_iter *it)
1284 {
1285 struct sk_buff *skb;
1286 size_t linear;
1287 int err;
1288 int i;
1289
1290 if (it->nr_segs > MAX_SKB_FRAGS + 1)
1291 return ERR_PTR(-ENOMEM);
1292
1293 local_bh_disable();
1294 skb = napi_get_frags(&tfile->napi);
1295 local_bh_enable();
1296 if (!skb)
1297 return ERR_PTR(-ENOMEM);
1298
1299 linear = iov_iter_single_seg_count(it);
1300 err = __skb_grow(skb, linear);
1301 if (err)
1302 goto free;
1303
1304 skb->len = len;
1305 skb->data_len = len - linear;
1306 skb->truesize += skb->data_len;
1307
1308 for (i = 1; i < it->nr_segs; i++) {
1309 size_t fragsz = it->iov[i].iov_len;
1310 unsigned long offset;
1311 struct page *page;
1312 void *data;
1313
1314 if (fragsz == 0 || fragsz > PAGE_SIZE) {
1315 err = -EINVAL;
1316 goto free;
1317 }
1318
1319 local_bh_disable();
1320 data = napi_alloc_frag(fragsz);
1321 local_bh_enable();
1322 if (!data) {
1323 err = -ENOMEM;
1324 goto free;
1325 }
1326
1327 page = virt_to_head_page(data);
1328 offset = data - page_address(page);
1329 skb_fill_page_desc(skb, i - 1, page, offset, fragsz);
1330 }
1331
1332 return skb;
1333 free:
1334 /* frees skb and all frags allocated with napi_alloc_frag() */
1335 napi_free_frags(&tfile->napi);
1336 return ERR_PTR(err);
1337 }
1338
1339 /* prepad is the amount to reserve at front. len is length after that.
1340 * linear is a hint as to how much to copy (usually headers). */
1341 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1342 size_t prepad, size_t len,
1343 size_t linear, int noblock)
1344 {
1345 struct sock *sk = tfile->socket.sk;
1346 struct sk_buff *skb;
1347 int err;
1348
1349 /* Under a page? Don't bother with paged skb. */
1350 if (prepad + len < PAGE_SIZE || !linear)
1351 linear = len;
1352
1353 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1354 &err, 0);
1355 if (!skb)
1356 return ERR_PTR(err);
1357
1358 skb_reserve(skb, prepad);
1359 skb_put(skb, linear);
1360 skb->data_len = len - linear;
1361 skb->len += len - linear;
1362
1363 return skb;
1364 }
1365
1366 static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile,
1367 struct sk_buff *skb, int more)
1368 {
1369 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1370 struct sk_buff_head process_queue;
1371 u32 rx_batched = tun->rx_batched;
1372 bool rcv = false;
1373
1374 if (!rx_batched || (!more && skb_queue_empty(queue))) {
1375 local_bh_disable();
1376 netif_receive_skb(skb);
1377 local_bh_enable();
1378 return;
1379 }
1380
1381 spin_lock(&queue->lock);
1382 if (!more || skb_queue_len(queue) == rx_batched) {
1383 __skb_queue_head_init(&process_queue);
1384 skb_queue_splice_tail_init(queue, &process_queue);
1385 rcv = true;
1386 } else {
1387 __skb_queue_tail(queue, skb);
1388 }
1389 spin_unlock(&queue->lock);
1390
1391 if (rcv) {
1392 struct sk_buff *nskb;
1393
1394 local_bh_disable();
1395 while ((nskb = __skb_dequeue(&process_queue)))
1396 netif_receive_skb(nskb);
1397 netif_receive_skb(skb);
1398 local_bh_enable();
1399 }
1400 }
1401
1402 static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile,
1403 int len, int noblock, bool zerocopy)
1404 {
1405 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
1406 return false;
1407
1408 if (tfile->socket.sk->sk_sndbuf != INT_MAX)
1409 return false;
1410
1411 if (!noblock)
1412 return false;
1413
1414 if (zerocopy)
1415 return false;
1416
1417 if (SKB_DATA_ALIGN(len + TUN_RX_PAD) +
1418 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
1419 return false;
1420
1421 return true;
1422 }
1423
1424 static struct sk_buff *tun_build_skb(struct tun_struct *tun,
1425 struct tun_file *tfile,
1426 struct iov_iter *from,
1427 struct virtio_net_hdr *hdr,
1428 int len, int *skb_xdp)
1429 {
1430 struct page_frag *alloc_frag = &current->task_frag;
1431 struct sk_buff *skb;
1432 struct bpf_prog *xdp_prog;
1433 int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1434 unsigned int delta = 0;
1435 char *buf;
1436 size_t copied;
1437 bool xdp_xmit = false;
1438 int err, pad = TUN_RX_PAD;
1439
1440 rcu_read_lock();
1441 xdp_prog = rcu_dereference(tun->xdp_prog);
1442 if (xdp_prog)
1443 pad += TUN_HEADROOM;
1444 buflen += SKB_DATA_ALIGN(len + pad);
1445 rcu_read_unlock();
1446
1447 alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES);
1448 if (unlikely(!skb_page_frag_refill(buflen, alloc_frag, GFP_KERNEL)))
1449 return ERR_PTR(-ENOMEM);
1450
1451 buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
1452 copied = copy_page_from_iter(alloc_frag->page,
1453 alloc_frag->offset + pad,
1454 len, from);
1455 if (copied != len)
1456 return ERR_PTR(-EFAULT);
1457
1458 /* There's a small window that XDP may be set after the check
1459 * of xdp_prog above, this should be rare and for simplicity
1460 * we do XDP on skb in case the headroom is not enough.
1461 */
1462 if (hdr->gso_type || !xdp_prog)
1463 *skb_xdp = 1;
1464 else
1465 *skb_xdp = 0;
1466
1467 rcu_read_lock();
1468 xdp_prog = rcu_dereference(tun->xdp_prog);
1469 if (xdp_prog && !*skb_xdp) {
1470 struct xdp_buff xdp;
1471 void *orig_data;
1472 u32 act;
1473
1474 xdp.data_hard_start = buf;
1475 xdp.data = buf + pad;
1476 xdp_set_data_meta_invalid(&xdp);
1477 xdp.data_end = xdp.data + len;
1478 orig_data = xdp.data;
1479 act = bpf_prog_run_xdp(xdp_prog, &xdp);
1480
1481 switch (act) {
1482 case XDP_REDIRECT:
1483 get_page(alloc_frag->page);
1484 alloc_frag->offset += buflen;
1485 err = xdp_do_redirect(tun->dev, &xdp, xdp_prog);
1486 if (err)
1487 goto err_redirect;
1488 rcu_read_unlock();
1489 return NULL;
1490 case XDP_TX:
1491 xdp_xmit = true;
1492 /* fall through */
1493 case XDP_PASS:
1494 delta = orig_data - xdp.data;
1495 break;
1496 default:
1497 bpf_warn_invalid_xdp_action(act);
1498 /* fall through */
1499 case XDP_ABORTED:
1500 trace_xdp_exception(tun->dev, xdp_prog, act);
1501 /* fall through */
1502 case XDP_DROP:
1503 goto err_xdp;
1504 }
1505 }
1506
1507 skb = build_skb(buf, buflen);
1508 if (!skb) {
1509 rcu_read_unlock();
1510 return ERR_PTR(-ENOMEM);
1511 }
1512
1513 skb_reserve(skb, pad - delta);
1514 skb_put(skb, len + delta);
1515 get_page(alloc_frag->page);
1516 alloc_frag->offset += buflen;
1517
1518 if (xdp_xmit) {
1519 skb->dev = tun->dev;
1520 generic_xdp_tx(skb, xdp_prog);
1521 rcu_read_unlock();
1522 return NULL;
1523 }
1524
1525 rcu_read_unlock();
1526
1527 return skb;
1528
1529 err_redirect:
1530 put_page(alloc_frag->page);
1531 err_xdp:
1532 rcu_read_unlock();
1533 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1534 return NULL;
1535 }
1536
1537 /* Get packet from user space buffer */
1538 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1539 void *msg_control, struct iov_iter *from,
1540 int noblock, bool more)
1541 {
1542 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1543 struct sk_buff *skb;
1544 size_t total_len = iov_iter_count(from);
1545 size_t len = total_len, align = tun->align, linear;
1546 struct virtio_net_hdr gso = { 0 };
1547 struct tun_pcpu_stats *stats;
1548 int good_linear;
1549 int copylen;
1550 bool zerocopy = false;
1551 int err;
1552 u32 rxhash;
1553 int skb_xdp = 1;
1554 bool frags = tun_napi_frags_enabled(tun);
1555
1556 if (!(tun->dev->flags & IFF_UP))
1557 return -EIO;
1558
1559 if (!(tun->flags & IFF_NO_PI)) {
1560 if (len < sizeof(pi))
1561 return -EINVAL;
1562 len -= sizeof(pi);
1563
1564 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1565 return -EFAULT;
1566 }
1567
1568 if (tun->flags & IFF_VNET_HDR) {
1569 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1570
1571 if (len < vnet_hdr_sz)
1572 return -EINVAL;
1573 len -= vnet_hdr_sz;
1574
1575 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1576 return -EFAULT;
1577
1578 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1579 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1580 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1581
1582 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1583 return -EINVAL;
1584 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1585 }
1586
1587 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1588 align += NET_IP_ALIGN;
1589 if (unlikely(len < ETH_HLEN ||
1590 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1591 return -EINVAL;
1592 }
1593
1594 good_linear = SKB_MAX_HEAD(align);
1595
1596 if (msg_control) {
1597 struct iov_iter i = *from;
1598
1599 /* There are 256 bytes to be copied in skb, so there is
1600 * enough room for skb expand head in case it is used.
1601 * The rest of the buffer is mapped from userspace.
1602 */
1603 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1604 if (copylen > good_linear)
1605 copylen = good_linear;
1606 linear = copylen;
1607 iov_iter_advance(&i, copylen);
1608 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1609 zerocopy = true;
1610 }
1611
1612 if (!frags && tun_can_build_skb(tun, tfile, len, noblock, zerocopy)) {
1613 /* For the packet that is not easy to be processed
1614 * (e.g gso or jumbo packet), we will do it at after
1615 * skb was created with generic XDP routine.
1616 */
1617 skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp);
1618 if (IS_ERR(skb)) {
1619 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1620 return PTR_ERR(skb);
1621 }
1622 if (!skb)
1623 return total_len;
1624 } else {
1625 if (!zerocopy) {
1626 copylen = len;
1627 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1628 linear = good_linear;
1629 else
1630 linear = tun16_to_cpu(tun, gso.hdr_len);
1631 }
1632
1633 if (frags) {
1634 mutex_lock(&tfile->napi_mutex);
1635 skb = tun_napi_alloc_frags(tfile, copylen, from);
1636 /* tun_napi_alloc_frags() enforces a layout for the skb.
1637 * If zerocopy is enabled, then this layout will be
1638 * overwritten by zerocopy_sg_from_iter().
1639 */
1640 zerocopy = false;
1641 } else {
1642 skb = tun_alloc_skb(tfile, align, copylen, linear,
1643 noblock);
1644 }
1645
1646 if (IS_ERR(skb)) {
1647 if (PTR_ERR(skb) != -EAGAIN)
1648 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1649 if (frags)
1650 mutex_unlock(&tfile->napi_mutex);
1651 return PTR_ERR(skb);
1652 }
1653
1654 if (zerocopy)
1655 err = zerocopy_sg_from_iter(skb, from);
1656 else
1657 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1658
1659 if (err) {
1660 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1661 kfree_skb(skb);
1662 if (frags) {
1663 tfile->napi.skb = NULL;
1664 mutex_unlock(&tfile->napi_mutex);
1665 }
1666
1667 return -EFAULT;
1668 }
1669 }
1670
1671 if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1672 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
1673 kfree_skb(skb);
1674 if (frags) {
1675 tfile->napi.skb = NULL;
1676 mutex_unlock(&tfile->napi_mutex);
1677 }
1678
1679 return -EINVAL;
1680 }
1681
1682 switch (tun->flags & TUN_TYPE_MASK) {
1683 case IFF_TUN:
1684 if (tun->flags & IFF_NO_PI) {
1685 u8 ip_version = skb->len ? (skb->data[0] >> 4) : 0;
1686
1687 switch (ip_version) {
1688 case 4:
1689 pi.proto = htons(ETH_P_IP);
1690 break;
1691 case 6:
1692 pi.proto = htons(ETH_P_IPV6);
1693 break;
1694 default:
1695 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1696 kfree_skb(skb);
1697 return -EINVAL;
1698 }
1699 }
1700
1701 skb_reset_mac_header(skb);
1702 skb->protocol = pi.proto;
1703 skb->dev = tun->dev;
1704 break;
1705 case IFF_TAP:
1706 if (!frags)
1707 skb->protocol = eth_type_trans(skb, tun->dev);
1708 break;
1709 }
1710
1711 /* copy skb_ubuf_info for callback when skb has no error */
1712 if (zerocopy) {
1713 skb_shinfo(skb)->destructor_arg = msg_control;
1714 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1715 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1716 } else if (msg_control) {
1717 struct ubuf_info *uarg = msg_control;
1718 uarg->callback(uarg, false);
1719 }
1720
1721 skb_reset_network_header(skb);
1722 skb_probe_transport_header(skb, 0);
1723
1724 if (skb_xdp) {
1725 struct bpf_prog *xdp_prog;
1726 int ret;
1727
1728 rcu_read_lock();
1729 xdp_prog = rcu_dereference(tun->xdp_prog);
1730 if (xdp_prog) {
1731 ret = do_xdp_generic(xdp_prog, skb);
1732 if (ret != XDP_PASS) {
1733 rcu_read_unlock();
1734 return total_len;
1735 }
1736 }
1737 rcu_read_unlock();
1738 }
1739
1740 rxhash = __skb_get_hash_symmetric(skb);
1741
1742 if (frags) {
1743 /* Exercise flow dissector code path. */
1744 u32 headlen = eth_get_headlen(skb->data, skb_headlen(skb));
1745
1746 if (unlikely(headlen > skb_headlen(skb))) {
1747 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1748 napi_free_frags(&tfile->napi);
1749 mutex_unlock(&tfile->napi_mutex);
1750 WARN_ON(1);
1751 return -ENOMEM;
1752 }
1753
1754 local_bh_disable();
1755 napi_gro_frags(&tfile->napi);
1756 local_bh_enable();
1757 mutex_unlock(&tfile->napi_mutex);
1758 } else if (tfile->napi_enabled) {
1759 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1760 int queue_len;
1761
1762 spin_lock_bh(&queue->lock);
1763 __skb_queue_tail(queue, skb);
1764 queue_len = skb_queue_len(queue);
1765 spin_unlock(&queue->lock);
1766
1767 if (!more || queue_len > NAPI_POLL_WEIGHT)
1768 napi_schedule(&tfile->napi);
1769
1770 local_bh_enable();
1771 } else if (!IS_ENABLED(CONFIG_4KSTACKS)) {
1772 tun_rx_batched(tun, tfile, skb, more);
1773 } else {
1774 netif_rx_ni(skb);
1775 }
1776
1777 stats = get_cpu_ptr(tun->pcpu_stats);
1778 u64_stats_update_begin(&stats->syncp);
1779 stats->rx_packets++;
1780 stats->rx_bytes += len;
1781 u64_stats_update_end(&stats->syncp);
1782 put_cpu_ptr(stats);
1783
1784 tun_flow_update(tun, rxhash, tfile);
1785 return total_len;
1786 }
1787
1788 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
1789 {
1790 struct file *file = iocb->ki_filp;
1791 struct tun_file *tfile = file->private_data;
1792 struct tun_struct *tun = tun_get(tfile);
1793 ssize_t result;
1794
1795 if (!tun)
1796 return -EBADFD;
1797
1798 result = tun_get_user(tun, tfile, NULL, from,
1799 file->f_flags & O_NONBLOCK, false);
1800
1801 tun_put(tun);
1802 return result;
1803 }
1804
1805 /* Put packet to the user space buffer */
1806 static ssize_t tun_put_user(struct tun_struct *tun,
1807 struct tun_file *tfile,
1808 struct sk_buff *skb,
1809 struct iov_iter *iter)
1810 {
1811 struct tun_pi pi = { 0, skb->protocol };
1812 struct tun_pcpu_stats *stats;
1813 ssize_t total;
1814 int vlan_offset = 0;
1815 int vlan_hlen = 0;
1816 int vnet_hdr_sz = 0;
1817
1818 if (skb_vlan_tag_present(skb))
1819 vlan_hlen = VLAN_HLEN;
1820
1821 if (tun->flags & IFF_VNET_HDR)
1822 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1823
1824 total = skb->len + vlan_hlen + vnet_hdr_sz;
1825
1826 if (!(tun->flags & IFF_NO_PI)) {
1827 if (iov_iter_count(iter) < sizeof(pi))
1828 return -EINVAL;
1829
1830 total += sizeof(pi);
1831 if (iov_iter_count(iter) < total) {
1832 /* Packet will be striped */
1833 pi.flags |= TUN_PKT_STRIP;
1834 }
1835
1836 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
1837 return -EFAULT;
1838 }
1839
1840 if (vnet_hdr_sz) {
1841 struct virtio_net_hdr gso;
1842
1843 if (iov_iter_count(iter) < vnet_hdr_sz)
1844 return -EINVAL;
1845
1846 if (virtio_net_hdr_from_skb(skb, &gso,
1847 tun_is_little_endian(tun), true)) {
1848 struct skb_shared_info *sinfo = skb_shinfo(skb);
1849 pr_err("unexpected GSO type: "
1850 "0x%x, gso_size %d, hdr_len %d\n",
1851 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
1852 tun16_to_cpu(tun, gso.hdr_len));
1853 print_hex_dump(KERN_ERR, "tun: ",
1854 DUMP_PREFIX_NONE,
1855 16, 1, skb->head,
1856 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
1857 WARN_ON_ONCE(1);
1858 return -EINVAL;
1859 }
1860
1861 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
1862 return -EFAULT;
1863
1864 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
1865 }
1866
1867 if (vlan_hlen) {
1868 int ret;
1869 struct {
1870 __be16 h_vlan_proto;
1871 __be16 h_vlan_TCI;
1872 } veth;
1873
1874 veth.h_vlan_proto = skb->vlan_proto;
1875 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
1876
1877 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
1878
1879 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
1880 if (ret || !iov_iter_count(iter))
1881 goto done;
1882
1883 ret = copy_to_iter(&veth, sizeof(veth), iter);
1884 if (ret != sizeof(veth) || !iov_iter_count(iter))
1885 goto done;
1886 }
1887
1888 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
1889
1890 done:
1891 /* caller is in process context, */
1892 stats = get_cpu_ptr(tun->pcpu_stats);
1893 u64_stats_update_begin(&stats->syncp);
1894 stats->tx_packets++;
1895 stats->tx_bytes += skb->len + vlan_hlen;
1896 u64_stats_update_end(&stats->syncp);
1897 put_cpu_ptr(tun->pcpu_stats);
1898
1899 return total;
1900 }
1901
1902 static struct sk_buff *tun_ring_recv(struct tun_file *tfile, int noblock,
1903 int *err)
1904 {
1905 DECLARE_WAITQUEUE(wait, current);
1906 struct sk_buff *skb = NULL;
1907 int error = 0;
1908
1909 skb = skb_array_consume(&tfile->tx_array);
1910 if (skb)
1911 goto out;
1912 if (noblock) {
1913 error = -EAGAIN;
1914 goto out;
1915 }
1916
1917 add_wait_queue(&tfile->wq.wait, &wait);
1918 current->state = TASK_INTERRUPTIBLE;
1919
1920 while (1) {
1921 skb = skb_array_consume(&tfile->tx_array);
1922 if (skb)
1923 break;
1924 if (signal_pending(current)) {
1925 error = -ERESTARTSYS;
1926 break;
1927 }
1928 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
1929 error = -EFAULT;
1930 break;
1931 }
1932
1933 schedule();
1934 }
1935
1936 current->state = TASK_RUNNING;
1937 remove_wait_queue(&tfile->wq.wait, &wait);
1938
1939 out:
1940 *err = error;
1941 return skb;
1942 }
1943
1944 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
1945 struct iov_iter *to,
1946 int noblock, struct sk_buff *skb)
1947 {
1948 ssize_t ret;
1949 int err;
1950
1951 tun_debug(KERN_INFO, tun, "tun_do_read\n");
1952
1953 if (!iov_iter_count(to))
1954 return 0;
1955
1956 if (!skb) {
1957 /* Read frames from ring */
1958 skb = tun_ring_recv(tfile, noblock, &err);
1959 if (!skb)
1960 return err;
1961 }
1962
1963 ret = tun_put_user(tun, tfile, skb, to);
1964 if (unlikely(ret < 0))
1965 kfree_skb(skb);
1966 else
1967 consume_skb(skb);
1968
1969 return ret;
1970 }
1971
1972 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
1973 {
1974 struct file *file = iocb->ki_filp;
1975 struct tun_file *tfile = file->private_data;
1976 struct tun_struct *tun = tun_get(tfile);
1977 ssize_t len = iov_iter_count(to), ret;
1978
1979 if (!tun)
1980 return -EBADFD;
1981 ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK, NULL);
1982 ret = min_t(ssize_t, ret, len);
1983 if (ret > 0)
1984 iocb->ki_pos = ret;
1985 tun_put(tun);
1986 return ret;
1987 }
1988
1989 static void tun_free_netdev(struct net_device *dev)
1990 {
1991 struct tun_struct *tun = netdev_priv(dev);
1992
1993 BUG_ON(!(list_empty(&tun->disabled)));
1994 free_percpu(tun->pcpu_stats);
1995 tun_flow_uninit(tun);
1996 security_tun_dev_free_security(tun->security);
1997 }
1998
1999 static void tun_setup(struct net_device *dev)
2000 {
2001 struct tun_struct *tun = netdev_priv(dev);
2002
2003 tun->owner = INVALID_UID;
2004 tun->group = INVALID_GID;
2005
2006 dev->ethtool_ops = &tun_ethtool_ops;
2007 dev->needs_free_netdev = true;
2008 dev->priv_destructor = tun_free_netdev;
2009 /* We prefer our own queue length */
2010 dev->tx_queue_len = TUN_READQ_SIZE;
2011 }
2012
2013 /* Trivial set of netlink ops to allow deleting tun or tap
2014 * device with netlink.
2015 */
2016 static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
2017 struct netlink_ext_ack *extack)
2018 {
2019 return -EINVAL;
2020 }
2021
2022 static struct rtnl_link_ops tun_link_ops __read_mostly = {
2023 .kind = DRV_NAME,
2024 .priv_size = sizeof(struct tun_struct),
2025 .setup = tun_setup,
2026 .validate = tun_validate,
2027 };
2028
2029 static void tun_sock_write_space(struct sock *sk)
2030 {
2031 struct tun_file *tfile;
2032 wait_queue_head_t *wqueue;
2033
2034 if (!sock_writeable(sk))
2035 return;
2036
2037 if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
2038 return;
2039
2040 wqueue = sk_sleep(sk);
2041 if (wqueue && waitqueue_active(wqueue))
2042 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
2043 POLLWRNORM | POLLWRBAND);
2044
2045 tfile = container_of(sk, struct tun_file, sk);
2046 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
2047 }
2048
2049 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
2050 {
2051 int ret;
2052 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2053 struct tun_struct *tun = tun_get(tfile);
2054
2055 if (!tun)
2056 return -EBADFD;
2057
2058 ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter,
2059 m->msg_flags & MSG_DONTWAIT,
2060 m->msg_flags & MSG_MORE);
2061 tun_put(tun);
2062 return ret;
2063 }
2064
2065 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
2066 int flags)
2067 {
2068 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2069 struct tun_struct *tun = tun_get(tfile);
2070 int ret;
2071
2072 if (!tun)
2073 return -EBADFD;
2074
2075 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
2076 ret = -EINVAL;
2077 goto out;
2078 }
2079 if (flags & MSG_ERRQUEUE) {
2080 ret = sock_recv_errqueue(sock->sk, m, total_len,
2081 SOL_PACKET, TUN_TX_TIMESTAMP);
2082 goto out;
2083 }
2084 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT,
2085 m->msg_control);
2086 if (ret > (ssize_t)total_len) {
2087 m->msg_flags |= MSG_TRUNC;
2088 ret = flags & MSG_TRUNC ? ret : total_len;
2089 }
2090 out:
2091 tun_put(tun);
2092 return ret;
2093 }
2094
2095 static int tun_peek_len(struct socket *sock)
2096 {
2097 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2098 struct tun_struct *tun;
2099 int ret = 0;
2100
2101 tun = tun_get(tfile);
2102 if (!tun)
2103 return 0;
2104
2105 ret = skb_array_peek_len(&tfile->tx_array);
2106 tun_put(tun);
2107
2108 return ret;
2109 }
2110
2111 /* Ops structure to mimic raw sockets with tun */
2112 static const struct proto_ops tun_socket_ops = {
2113 .peek_len = tun_peek_len,
2114 .sendmsg = tun_sendmsg,
2115 .recvmsg = tun_recvmsg,
2116 };
2117
2118 static struct proto tun_proto = {
2119 .name = "tun",
2120 .owner = THIS_MODULE,
2121 .obj_size = sizeof(struct tun_file),
2122 };
2123
2124 static int tun_flags(struct tun_struct *tun)
2125 {
2126 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
2127 }
2128
2129 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
2130 char *buf)
2131 {
2132 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2133 return sprintf(buf, "0x%x\n", tun_flags(tun));
2134 }
2135
2136 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
2137 char *buf)
2138 {
2139 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2140 return uid_valid(tun->owner)?
2141 sprintf(buf, "%u\n",
2142 from_kuid_munged(current_user_ns(), tun->owner)):
2143 sprintf(buf, "-1\n");
2144 }
2145
2146 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
2147 char *buf)
2148 {
2149 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2150 return gid_valid(tun->group) ?
2151 sprintf(buf, "%u\n",
2152 from_kgid_munged(current_user_ns(), tun->group)):
2153 sprintf(buf, "-1\n");
2154 }
2155
2156 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
2157 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
2158 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
2159
2160 static struct attribute *tun_dev_attrs[] = {
2161 &dev_attr_tun_flags.attr,
2162 &dev_attr_owner.attr,
2163 &dev_attr_group.attr,
2164 NULL
2165 };
2166
2167 static const struct attribute_group tun_attr_group = {
2168 .attrs = tun_dev_attrs
2169 };
2170
2171 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
2172 {
2173 struct tun_struct *tun;
2174 struct tun_file *tfile = file->private_data;
2175 struct net_device *dev;
2176 int err;
2177
2178 if (tfile->detached)
2179 return -EINVAL;
2180
2181 if ((ifr->ifr_flags & IFF_NAPI_FRAGS)) {
2182 if (!capable(CAP_NET_ADMIN))
2183 return -EPERM;
2184
2185 if (!(ifr->ifr_flags & IFF_NAPI) ||
2186 (ifr->ifr_flags & TUN_TYPE_MASK) != IFF_TAP)
2187 return -EINVAL;
2188 }
2189
2190 dev = __dev_get_by_name(net, ifr->ifr_name);
2191 if (dev) {
2192 if (ifr->ifr_flags & IFF_TUN_EXCL)
2193 return -EBUSY;
2194 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
2195 tun = netdev_priv(dev);
2196 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
2197 tun = netdev_priv(dev);
2198 else
2199 return -EINVAL;
2200
2201 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
2202 !!(tun->flags & IFF_MULTI_QUEUE))
2203 return -EINVAL;
2204
2205 if (tun_not_capable(tun))
2206 return -EPERM;
2207 err = security_tun_dev_open(tun->security);
2208 if (err < 0)
2209 return err;
2210
2211 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER,
2212 ifr->ifr_flags & IFF_NAPI);
2213 if (err < 0)
2214 return err;
2215
2216 if (tun->flags & IFF_MULTI_QUEUE &&
2217 (tun->numqueues + tun->numdisabled > 1)) {
2218 /* One or more queue has already been attached, no need
2219 * to initialize the device again.
2220 */
2221 return 0;
2222 }
2223 }
2224 else {
2225 char *name;
2226 unsigned long flags = 0;
2227 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
2228 MAX_TAP_QUEUES : 1;
2229
2230 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2231 return -EPERM;
2232 err = security_tun_dev_create();
2233 if (err < 0)
2234 return err;
2235
2236 /* Set dev type */
2237 if (ifr->ifr_flags & IFF_TUN) {
2238 /* TUN device */
2239 flags |= IFF_TUN;
2240 name = "tun%d";
2241 } else if (ifr->ifr_flags & IFF_TAP) {
2242 /* TAP device */
2243 flags |= IFF_TAP;
2244 name = "tap%d";
2245 } else
2246 return -EINVAL;
2247
2248 if (*ifr->ifr_name)
2249 name = ifr->ifr_name;
2250
2251 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
2252 NET_NAME_UNKNOWN, tun_setup, queues,
2253 queues);
2254
2255 if (!dev)
2256 return -ENOMEM;
2257 err = dev_get_valid_name(net, dev, name);
2258 if (err < 0)
2259 goto err_free_dev;
2260
2261 dev_net_set(dev, net);
2262 dev->rtnl_link_ops = &tun_link_ops;
2263 dev->ifindex = tfile->ifindex;
2264 dev->sysfs_groups[0] = &tun_attr_group;
2265
2266 tun = netdev_priv(dev);
2267 tun->dev = dev;
2268 tun->flags = flags;
2269 tun->txflt.count = 0;
2270 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
2271
2272 tun->align = NET_SKB_PAD;
2273 tun->filter_attached = false;
2274 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
2275 tun->rx_batched = 0;
2276
2277 tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats);
2278 if (!tun->pcpu_stats) {
2279 err = -ENOMEM;
2280 goto err_free_dev;
2281 }
2282
2283 spin_lock_init(&tun->lock);
2284
2285 err = security_tun_dev_alloc_security(&tun->security);
2286 if (err < 0)
2287 goto err_free_stat;
2288
2289 tun_net_init(dev);
2290 tun_flow_init(tun);
2291
2292 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
2293 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
2294 NETIF_F_HW_VLAN_STAG_TX;
2295 dev->features = dev->hw_features | NETIF_F_LLTX;
2296 dev->vlan_features = dev->features &
2297 ~(NETIF_F_HW_VLAN_CTAG_TX |
2298 NETIF_F_HW_VLAN_STAG_TX);
2299
2300 INIT_LIST_HEAD(&tun->disabled);
2301 err = tun_attach(tun, file, false, ifr->ifr_flags & IFF_NAPI);
2302 if (err < 0)
2303 goto err_free_flow;
2304
2305 err = register_netdevice(tun->dev);
2306 if (err < 0)
2307 goto err_detach;
2308 }
2309
2310 netif_carrier_on(tun->dev);
2311
2312 tun_debug(KERN_INFO, tun, "tun_set_iff\n");
2313
2314 tun->flags = (tun->flags & ~TUN_FEATURES) |
2315 (ifr->ifr_flags & TUN_FEATURES);
2316
2317 /* Make sure persistent devices do not get stuck in
2318 * xoff state.
2319 */
2320 if (netif_running(tun->dev))
2321 netif_tx_wake_all_queues(tun->dev);
2322
2323 strcpy(ifr->ifr_name, tun->dev->name);
2324 return 0;
2325
2326 err_detach:
2327 tun_detach_all(dev);
2328 /* register_netdevice() already called tun_free_netdev() */
2329 goto err_free_dev;
2330
2331 err_free_flow:
2332 tun_flow_uninit(tun);
2333 security_tun_dev_free_security(tun->security);
2334 err_free_stat:
2335 free_percpu(tun->pcpu_stats);
2336 err_free_dev:
2337 free_netdev(dev);
2338 return err;
2339 }
2340
2341 static void tun_get_iff(struct net *net, struct tun_struct *tun,
2342 struct ifreq *ifr)
2343 {
2344 tun_debug(KERN_INFO, tun, "tun_get_iff\n");
2345
2346 strcpy(ifr->ifr_name, tun->dev->name);
2347
2348 ifr->ifr_flags = tun_flags(tun);
2349
2350 }
2351
2352 /* This is like a cut-down ethtool ops, except done via tun fd so no
2353 * privs required. */
2354 static int set_offload(struct tun_struct *tun, unsigned long arg)
2355 {
2356 netdev_features_t features = 0;
2357
2358 if (arg & TUN_F_CSUM) {
2359 features |= NETIF_F_HW_CSUM;
2360 arg &= ~TUN_F_CSUM;
2361
2362 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
2363 if (arg & TUN_F_TSO_ECN) {
2364 features |= NETIF_F_TSO_ECN;
2365 arg &= ~TUN_F_TSO_ECN;
2366 }
2367 if (arg & TUN_F_TSO4)
2368 features |= NETIF_F_TSO;
2369 if (arg & TUN_F_TSO6)
2370 features |= NETIF_F_TSO6;
2371 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
2372 }
2373 }
2374
2375 /* This gives the user a way to test for new features in future by
2376 * trying to set them. */
2377 if (arg)
2378 return -EINVAL;
2379
2380 tun->set_features = features;
2381 tun->dev->wanted_features &= ~TUN_USER_FEATURES;
2382 tun->dev->wanted_features |= features;
2383 netdev_update_features(tun->dev);
2384
2385 return 0;
2386 }
2387
2388 static void tun_detach_filter(struct tun_struct *tun, int n)
2389 {
2390 int i;
2391 struct tun_file *tfile;
2392
2393 for (i = 0; i < n; i++) {
2394 tfile = rtnl_dereference(tun->tfiles[i]);
2395 lock_sock(tfile->socket.sk);
2396 sk_detach_filter(tfile->socket.sk);
2397 release_sock(tfile->socket.sk);
2398 }
2399
2400 tun->filter_attached = false;
2401 }
2402
2403 static int tun_attach_filter(struct tun_struct *tun)
2404 {
2405 int i, ret = 0;
2406 struct tun_file *tfile;
2407
2408 for (i = 0; i < tun->numqueues; i++) {
2409 tfile = rtnl_dereference(tun->tfiles[i]);
2410 lock_sock(tfile->socket.sk);
2411 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
2412 release_sock(tfile->socket.sk);
2413 if (ret) {
2414 tun_detach_filter(tun, i);
2415 return ret;
2416 }
2417 }
2418
2419 tun->filter_attached = true;
2420 return ret;
2421 }
2422
2423 static void tun_set_sndbuf(struct tun_struct *tun)
2424 {
2425 struct tun_file *tfile;
2426 int i;
2427
2428 for (i = 0; i < tun->numqueues; i++) {
2429 tfile = rtnl_dereference(tun->tfiles[i]);
2430 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
2431 }
2432 }
2433
2434 static int tun_set_queue(struct file *file, struct ifreq *ifr)
2435 {
2436 struct tun_file *tfile = file->private_data;
2437 struct tun_struct *tun;
2438 int ret = 0;
2439
2440 rtnl_lock();
2441
2442 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
2443 tun = tfile->detached;
2444 if (!tun) {
2445 ret = -EINVAL;
2446 goto unlock;
2447 }
2448 ret = security_tun_dev_attach_queue(tun->security);
2449 if (ret < 0)
2450 goto unlock;
2451 ret = tun_attach(tun, file, false, tun->flags & IFF_NAPI);
2452 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
2453 tun = rtnl_dereference(tfile->tun);
2454 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
2455 ret = -EINVAL;
2456 else
2457 __tun_detach(tfile, false);
2458 } else
2459 ret = -EINVAL;
2460
2461 unlock:
2462 rtnl_unlock();
2463 return ret;
2464 }
2465
2466 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
2467 unsigned long arg, int ifreq_len)
2468 {
2469 struct tun_file *tfile = file->private_data;
2470 struct tun_struct *tun;
2471 void __user* argp = (void __user*)arg;
2472 struct ifreq ifr;
2473 kuid_t owner;
2474 kgid_t group;
2475 int sndbuf;
2476 int vnet_hdr_sz;
2477 unsigned int ifindex;
2478 int le;
2479 int ret;
2480
2481 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == SOCK_IOC_TYPE) {
2482 if (copy_from_user(&ifr, argp, ifreq_len))
2483 return -EFAULT;
2484 } else {
2485 memset(&ifr, 0, sizeof(ifr));
2486 }
2487 if (cmd == TUNGETFEATURES) {
2488 /* Currently this just means: "what IFF flags are valid?".
2489 * This is needed because we never checked for invalid flags on
2490 * TUNSETIFF.
2491 */
2492 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
2493 (unsigned int __user*)argp);
2494 } else if (cmd == TUNSETQUEUE)
2495 return tun_set_queue(file, &ifr);
2496
2497 ret = 0;
2498 rtnl_lock();
2499
2500 tun = tun_get(tfile);
2501 if (cmd == TUNSETIFF) {
2502 ret = -EEXIST;
2503 if (tun)
2504 goto unlock;
2505
2506 ifr.ifr_name[IFNAMSIZ-1] = '\0';
2507
2508 ret = tun_set_iff(sock_net(&tfile->sk), file, &ifr);
2509
2510 if (ret)
2511 goto unlock;
2512
2513 if (copy_to_user(argp, &ifr, ifreq_len))
2514 ret = -EFAULT;
2515 goto unlock;
2516 }
2517 if (cmd == TUNSETIFINDEX) {
2518 ret = -EPERM;
2519 if (tun)
2520 goto unlock;
2521
2522 ret = -EFAULT;
2523 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
2524 goto unlock;
2525
2526 ret = 0;
2527 tfile->ifindex = ifindex;
2528 goto unlock;
2529 }
2530
2531 ret = -EBADFD;
2532 if (!tun)
2533 goto unlock;
2534
2535 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
2536
2537 ret = 0;
2538 switch (cmd) {
2539 case TUNGETIFF:
2540 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2541
2542 if (tfile->detached)
2543 ifr.ifr_flags |= IFF_DETACH_QUEUE;
2544 if (!tfile->socket.sk->sk_filter)
2545 ifr.ifr_flags |= IFF_NOFILTER;
2546
2547 if (copy_to_user(argp, &ifr, ifreq_len))
2548 ret = -EFAULT;
2549 break;
2550
2551 case TUNSETNOCSUM:
2552 /* Disable/Enable checksum */
2553
2554 /* [unimplemented] */
2555 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
2556 arg ? "disabled" : "enabled");
2557 break;
2558
2559 case TUNSETPERSIST:
2560 /* Disable/Enable persist mode. Keep an extra reference to the
2561 * module to prevent the module being unprobed.
2562 */
2563 if (arg && !(tun->flags & IFF_PERSIST)) {
2564 tun->flags |= IFF_PERSIST;
2565 __module_get(THIS_MODULE);
2566 }
2567 if (!arg && (tun->flags & IFF_PERSIST)) {
2568 tun->flags &= ~IFF_PERSIST;
2569 module_put(THIS_MODULE);
2570 }
2571
2572 tun_debug(KERN_INFO, tun, "persist %s\n",
2573 arg ? "enabled" : "disabled");
2574 break;
2575
2576 case TUNSETOWNER:
2577 /* Set owner of the device */
2578 owner = make_kuid(current_user_ns(), arg);
2579 if (!uid_valid(owner)) {
2580 ret = -EINVAL;
2581 break;
2582 }
2583 tun->owner = owner;
2584 tun_debug(KERN_INFO, tun, "owner set to %u\n",
2585 from_kuid(&init_user_ns, tun->owner));
2586 break;
2587
2588 case TUNSETGROUP:
2589 /* Set group of the device */
2590 group = make_kgid(current_user_ns(), arg);
2591 if (!gid_valid(group)) {
2592 ret = -EINVAL;
2593 break;
2594 }
2595 tun->group = group;
2596 tun_debug(KERN_INFO, tun, "group set to %u\n",
2597 from_kgid(&init_user_ns, tun->group));
2598 break;
2599
2600 case TUNSETLINK:
2601 /* Only allow setting the type when the interface is down */
2602 if (tun->dev->flags & IFF_UP) {
2603 tun_debug(KERN_INFO, tun,
2604 "Linktype set failed because interface is up\n");
2605 ret = -EBUSY;
2606 } else {
2607 tun->dev->type = (int) arg;
2608 tun_debug(KERN_INFO, tun, "linktype set to %d\n",
2609 tun->dev->type);
2610 ret = 0;
2611 }
2612 break;
2613
2614 #ifdef TUN_DEBUG
2615 case TUNSETDEBUG:
2616 tun->debug = arg;
2617 break;
2618 #endif
2619 case TUNSETOFFLOAD:
2620 ret = set_offload(tun, arg);
2621 break;
2622
2623 case TUNSETTXFILTER:
2624 /* Can be set only for TAPs */
2625 ret = -EINVAL;
2626 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2627 break;
2628 ret = update_filter(&tun->txflt, (void __user *)arg);
2629 break;
2630
2631 case SIOCGIFHWADDR:
2632 /* Get hw address */
2633 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
2634 ifr.ifr_hwaddr.sa_family = tun->dev->type;
2635 if (copy_to_user(argp, &ifr, ifreq_len))
2636 ret = -EFAULT;
2637 break;
2638
2639 case SIOCSIFHWADDR:
2640 /* Set hw address */
2641 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
2642 ifr.ifr_hwaddr.sa_data);
2643
2644 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
2645 break;
2646
2647 case TUNGETSNDBUF:
2648 sndbuf = tfile->socket.sk->sk_sndbuf;
2649 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
2650 ret = -EFAULT;
2651 break;
2652
2653 case TUNSETSNDBUF:
2654 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
2655 ret = -EFAULT;
2656 break;
2657 }
2658 if (sndbuf <= 0) {
2659 ret = -EINVAL;
2660 break;
2661 }
2662
2663 tun->sndbuf = sndbuf;
2664 tun_set_sndbuf(tun);
2665 break;
2666
2667 case TUNGETVNETHDRSZ:
2668 vnet_hdr_sz = tun->vnet_hdr_sz;
2669 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
2670 ret = -EFAULT;
2671 break;
2672
2673 case TUNSETVNETHDRSZ:
2674 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
2675 ret = -EFAULT;
2676 break;
2677 }
2678 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
2679 ret = -EINVAL;
2680 break;
2681 }
2682
2683 tun->vnet_hdr_sz = vnet_hdr_sz;
2684 break;
2685
2686 case TUNGETVNETLE:
2687 le = !!(tun->flags & TUN_VNET_LE);
2688 if (put_user(le, (int __user *)argp))
2689 ret = -EFAULT;
2690 break;
2691
2692 case TUNSETVNETLE:
2693 if (get_user(le, (int __user *)argp)) {
2694 ret = -EFAULT;
2695 break;
2696 }
2697 if (le)
2698 tun->flags |= TUN_VNET_LE;
2699 else
2700 tun->flags &= ~TUN_VNET_LE;
2701 break;
2702
2703 case TUNGETVNETBE:
2704 ret = tun_get_vnet_be(tun, argp);
2705 break;
2706
2707 case TUNSETVNETBE:
2708 ret = tun_set_vnet_be(tun, argp);
2709 break;
2710
2711 case TUNATTACHFILTER:
2712 /* Can be set only for TAPs */
2713 ret = -EINVAL;
2714 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2715 break;
2716 ret = -EFAULT;
2717 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
2718 break;
2719
2720 ret = tun_attach_filter(tun);
2721 break;
2722
2723 case TUNDETACHFILTER:
2724 /* Can be set only for TAPs */
2725 ret = -EINVAL;
2726 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2727 break;
2728 ret = 0;
2729 tun_detach_filter(tun, tun->numqueues);
2730 break;
2731
2732 case TUNGETFILTER:
2733 ret = -EINVAL;
2734 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2735 break;
2736 ret = -EFAULT;
2737 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
2738 break;
2739 ret = 0;
2740 break;
2741
2742 default:
2743 ret = -EINVAL;
2744 break;
2745 }
2746
2747 unlock:
2748 rtnl_unlock();
2749 if (tun)
2750 tun_put(tun);
2751 return ret;
2752 }
2753
2754 static long tun_chr_ioctl(struct file *file,
2755 unsigned int cmd, unsigned long arg)
2756 {
2757 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
2758 }
2759
2760 #ifdef CONFIG_COMPAT
2761 static long tun_chr_compat_ioctl(struct file *file,
2762 unsigned int cmd, unsigned long arg)
2763 {
2764 switch (cmd) {
2765 case TUNSETIFF:
2766 case TUNGETIFF:
2767 case TUNSETTXFILTER:
2768 case TUNGETSNDBUF:
2769 case TUNSETSNDBUF:
2770 case SIOCGIFHWADDR:
2771 case SIOCSIFHWADDR:
2772 arg = (unsigned long)compat_ptr(arg);
2773 break;
2774 default:
2775 arg = (compat_ulong_t)arg;
2776 break;
2777 }
2778
2779 /*
2780 * compat_ifreq is shorter than ifreq, so we must not access beyond
2781 * the end of that structure. All fields that are used in this
2782 * driver are compatible though, we don't need to convert the
2783 * contents.
2784 */
2785 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
2786 }
2787 #endif /* CONFIG_COMPAT */
2788
2789 static int tun_chr_fasync(int fd, struct file *file, int on)
2790 {
2791 struct tun_file *tfile = file->private_data;
2792 int ret;
2793
2794 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
2795 goto out;
2796
2797 if (on) {
2798 __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
2799 tfile->flags |= TUN_FASYNC;
2800 } else
2801 tfile->flags &= ~TUN_FASYNC;
2802 ret = 0;
2803 out:
2804 return ret;
2805 }
2806
2807 static int tun_chr_open(struct inode *inode, struct file * file)
2808 {
2809 struct net *net = current->nsproxy->net_ns;
2810 struct tun_file *tfile;
2811
2812 DBG1(KERN_INFO, "tunX: tun_chr_open\n");
2813
2814 tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
2815 &tun_proto, 0);
2816 if (!tfile)
2817 return -ENOMEM;
2818 RCU_INIT_POINTER(tfile->tun, NULL);
2819 tfile->flags = 0;
2820 tfile->ifindex = 0;
2821
2822 init_waitqueue_head(&tfile->wq.wait);
2823 RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq);
2824
2825 tfile->socket.file = file;
2826 tfile->socket.ops = &tun_socket_ops;
2827
2828 sock_init_data(&tfile->socket, &tfile->sk);
2829
2830 tfile->sk.sk_write_space = tun_sock_write_space;
2831 tfile->sk.sk_sndbuf = INT_MAX;
2832
2833 file->private_data = tfile;
2834 INIT_LIST_HEAD(&tfile->next);
2835
2836 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
2837
2838 return 0;
2839 }
2840
2841 static int tun_chr_close(struct inode *inode, struct file *file)
2842 {
2843 struct tun_file *tfile = file->private_data;
2844
2845 tun_detach(tfile, true);
2846
2847 return 0;
2848 }
2849
2850 #ifdef CONFIG_PROC_FS
2851 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *file)
2852 {
2853 struct tun_file *tfile = file->private_data;
2854 struct tun_struct *tun;
2855 struct ifreq ifr;
2856
2857 memset(&ifr, 0, sizeof(ifr));
2858
2859 rtnl_lock();
2860 tun = tun_get(tfile);
2861 if (tun)
2862 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2863 rtnl_unlock();
2864
2865 if (tun)
2866 tun_put(tun);
2867
2868 seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
2869 }
2870 #endif
2871
2872 static const struct file_operations tun_fops = {
2873 .owner = THIS_MODULE,
2874 .llseek = no_llseek,
2875 .read_iter = tun_chr_read_iter,
2876 .write_iter = tun_chr_write_iter,
2877 .poll = tun_chr_poll,
2878 .unlocked_ioctl = tun_chr_ioctl,
2879 #ifdef CONFIG_COMPAT
2880 .compat_ioctl = tun_chr_compat_ioctl,
2881 #endif
2882 .open = tun_chr_open,
2883 .release = tun_chr_close,
2884 .fasync = tun_chr_fasync,
2885 #ifdef CONFIG_PROC_FS
2886 .show_fdinfo = tun_chr_show_fdinfo,
2887 #endif
2888 };
2889
2890 static struct miscdevice tun_miscdev = {
2891 .minor = TUN_MINOR,
2892 .name = "tun",
2893 .nodename = "net/tun",
2894 .fops = &tun_fops,
2895 };
2896
2897 /* ethtool interface */
2898
2899 static int tun_get_link_ksettings(struct net_device *dev,
2900 struct ethtool_link_ksettings *cmd)
2901 {
2902 ethtool_link_ksettings_zero_link_mode(cmd, supported);
2903 ethtool_link_ksettings_zero_link_mode(cmd, advertising);
2904 cmd->base.speed = SPEED_10;
2905 cmd->base.duplex = DUPLEX_FULL;
2906 cmd->base.port = PORT_TP;
2907 cmd->base.phy_address = 0;
2908 cmd->base.autoneg = AUTONEG_DISABLE;
2909 return 0;
2910 }
2911
2912 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
2913 {
2914 struct tun_struct *tun = netdev_priv(dev);
2915
2916 strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
2917 strlcpy(info->version, DRV_VERSION, sizeof(info->version));
2918
2919 switch (tun->flags & TUN_TYPE_MASK) {
2920 case IFF_TUN:
2921 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
2922 break;
2923 case IFF_TAP:
2924 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
2925 break;
2926 }
2927 }
2928
2929 static u32 tun_get_msglevel(struct net_device *dev)
2930 {
2931 #ifdef TUN_DEBUG
2932 struct tun_struct *tun = netdev_priv(dev);
2933 return tun->debug;
2934 #else
2935 return -EOPNOTSUPP;
2936 #endif
2937 }
2938
2939 static void tun_set_msglevel(struct net_device *dev, u32 value)
2940 {
2941 #ifdef TUN_DEBUG
2942 struct tun_struct *tun = netdev_priv(dev);
2943 tun->debug = value;
2944 #endif
2945 }
2946
2947 static int tun_get_coalesce(struct net_device *dev,
2948 struct ethtool_coalesce *ec)
2949 {
2950 struct tun_struct *tun = netdev_priv(dev);
2951
2952 ec->rx_max_coalesced_frames = tun->rx_batched;
2953
2954 return 0;
2955 }
2956
2957 static int tun_set_coalesce(struct net_device *dev,
2958 struct ethtool_coalesce *ec)
2959 {
2960 struct tun_struct *tun = netdev_priv(dev);
2961
2962 if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT)
2963 tun->rx_batched = NAPI_POLL_WEIGHT;
2964 else
2965 tun->rx_batched = ec->rx_max_coalesced_frames;
2966
2967 return 0;
2968 }
2969
2970 static const struct ethtool_ops tun_ethtool_ops = {
2971 .get_drvinfo = tun_get_drvinfo,
2972 .get_msglevel = tun_get_msglevel,
2973 .set_msglevel = tun_set_msglevel,
2974 .get_link = ethtool_op_get_link,
2975 .get_ts_info = ethtool_op_get_ts_info,
2976 .get_coalesce = tun_get_coalesce,
2977 .set_coalesce = tun_set_coalesce,
2978 .get_link_ksettings = tun_get_link_ksettings,
2979 };
2980
2981 static int tun_queue_resize(struct tun_struct *tun)
2982 {
2983 struct net_device *dev = tun->dev;
2984 struct tun_file *tfile;
2985 struct skb_array **arrays;
2986 int n = tun->numqueues + tun->numdisabled;
2987 int ret, i;
2988
2989 arrays = kmalloc_array(n, sizeof(*arrays), GFP_KERNEL);
2990 if (!arrays)
2991 return -ENOMEM;
2992
2993 for (i = 0; i < tun->numqueues; i++) {
2994 tfile = rtnl_dereference(tun->tfiles[i]);
2995 arrays[i] = &tfile->tx_array;
2996 }
2997 list_for_each_entry(tfile, &tun->disabled, next)
2998 arrays[i++] = &tfile->tx_array;
2999
3000 ret = skb_array_resize_multiple(arrays, n,
3001 dev->tx_queue_len, GFP_KERNEL);
3002
3003 kfree(arrays);
3004 return ret;
3005 }
3006
3007 static int tun_device_event(struct notifier_block *unused,
3008 unsigned long event, void *ptr)
3009 {
3010 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3011 struct tun_struct *tun = netdev_priv(dev);
3012
3013 if (dev->rtnl_link_ops != &tun_link_ops)
3014 return NOTIFY_DONE;
3015
3016 switch (event) {
3017 case NETDEV_CHANGE_TX_QUEUE_LEN:
3018 if (tun_queue_resize(tun))
3019 return NOTIFY_BAD;
3020 break;
3021 default:
3022 break;
3023 }
3024
3025 return NOTIFY_DONE;
3026 }
3027
3028 static struct notifier_block tun_notifier_block __read_mostly = {
3029 .notifier_call = tun_device_event,
3030 };
3031
3032 static int __init tun_init(void)
3033 {
3034 int ret = 0;
3035
3036 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
3037
3038 ret = rtnl_link_register(&tun_link_ops);
3039 if (ret) {
3040 pr_err("Can't register link_ops\n");
3041 goto err_linkops;
3042 }
3043
3044 ret = misc_register(&tun_miscdev);
3045 if (ret) {
3046 pr_err("Can't register misc device %d\n", TUN_MINOR);
3047 goto err_misc;
3048 }
3049
3050 ret = register_netdevice_notifier(&tun_notifier_block);
3051 if (ret) {
3052 pr_err("Can't register netdevice notifier\n");
3053 goto err_notifier;
3054 }
3055
3056 return 0;
3057
3058 err_notifier:
3059 misc_deregister(&tun_miscdev);
3060 err_misc:
3061 rtnl_link_unregister(&tun_link_ops);
3062 err_linkops:
3063 return ret;
3064 }
3065
3066 static void tun_cleanup(void)
3067 {
3068 misc_deregister(&tun_miscdev);
3069 rtnl_link_unregister(&tun_link_ops);
3070 unregister_netdevice_notifier(&tun_notifier_block);
3071 }
3072
3073 /* Get an underlying socket object from tun file. Returns error unless file is
3074 * attached to a device. The returned object works like a packet socket, it
3075 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
3076 * holding a reference to the file for as long as the socket is in use. */
3077 struct socket *tun_get_socket(struct file *file)
3078 {
3079 struct tun_file *tfile;
3080 if (file->f_op != &tun_fops)
3081 return ERR_PTR(-EINVAL);
3082 tfile = file->private_data;
3083 if (!tfile)
3084 return ERR_PTR(-EBADFD);
3085 return &tfile->socket;
3086 }
3087 EXPORT_SYMBOL_GPL(tun_get_socket);
3088
3089 struct skb_array *tun_get_skb_array(struct file *file)
3090 {
3091 struct tun_file *tfile;
3092
3093 if (file->f_op != &tun_fops)
3094 return ERR_PTR(-EINVAL);
3095 tfile = file->private_data;
3096 if (!tfile)
3097 return ERR_PTR(-EBADFD);
3098 return &tfile->tx_array;
3099 }
3100 EXPORT_SYMBOL_GPL(tun_get_skb_array);
3101
3102 module_init(tun_init);
3103 module_exit(tun_cleanup);
3104 MODULE_DESCRIPTION(DRV_DESCRIPTION);
3105 MODULE_AUTHOR(DRV_COPYRIGHT);
3106 MODULE_LICENSE("GPL");
3107 MODULE_ALIAS_MISCDEV(TUN_MINOR);
3108 MODULE_ALIAS("devname:net/tun");
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