xref: /openbmc/linux/drivers/net/tun.c (revision 6f52b16c5b29b89d92c0e7236f4655dc8491ad70)
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 
79 #include <linux/uaccess.h>
80 
81 /* Uncomment to enable debugging */
82 /* #define TUN_DEBUG 1 */
83 
84 #ifdef TUN_DEBUG
85 static int debug;
86 
87 #define tun_debug(level, tun, fmt, args...)			\
88 do {								\
89 	if (tun->debug)						\
90 		netdev_printk(level, tun->dev, fmt, ##args);	\
91 } while (0)
92 #define DBG1(level, fmt, args...)				\
93 do {								\
94 	if (debug == 2)						\
95 		printk(level fmt, ##args);			\
96 } while (0)
97 #else
98 #define tun_debug(level, tun, fmt, args...)			\
99 do {								\
100 	if (0)							\
101 		netdev_printk(level, tun->dev, fmt, ##args);	\
102 } while (0)
103 #define DBG1(level, fmt, args...)				\
104 do {								\
105 	if (0)							\
106 		printk(level fmt, ##args);			\
107 } while (0)
108 #endif
109 
110 #define TUN_HEADROOM 256
111 #define TUN_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
112 
113 /* TUN device flags */
114 
115 /* IFF_ATTACH_QUEUE is never stored in device flags,
116  * overload it to mean fasync when stored there.
117  */
118 #define TUN_FASYNC	IFF_ATTACH_QUEUE
119 /* High bits in flags field are unused. */
120 #define TUN_VNET_LE     0x80000000
121 #define TUN_VNET_BE     0x40000000
122 
123 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
124 		      IFF_MULTI_QUEUE)
125 #define GOODCOPY_LEN 128
126 
127 #define FLT_EXACT_COUNT 8
128 struct tap_filter {
129 	unsigned int    count;    /* Number of addrs. Zero means disabled */
130 	u32             mask[2];  /* Mask of the hashed addrs */
131 	unsigned char	addr[FLT_EXACT_COUNT][ETH_ALEN];
132 };
133 
134 /* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
135  * to max number of VCPUs in guest. */
136 #define MAX_TAP_QUEUES 256
137 #define MAX_TAP_FLOWS  4096
138 
139 #define TUN_FLOW_EXPIRE (3 * HZ)
140 
141 struct tun_pcpu_stats {
142 	u64 rx_packets;
143 	u64 rx_bytes;
144 	u64 tx_packets;
145 	u64 tx_bytes;
146 	struct u64_stats_sync syncp;
147 	u32 rx_dropped;
148 	u32 tx_dropped;
149 	u32 rx_frame_errors;
150 };
151 
152 /* A tun_file connects an open character device to a tuntap netdevice. It
153  * also contains all socket related structures (except sock_fprog and tap_filter)
154  * to serve as one transmit queue for tuntap device. The sock_fprog and
155  * tap_filter were kept in tun_struct since they were used for filtering for the
156  * netdevice not for a specific queue (at least I didn't see the requirement for
157  * this).
158  *
159  * RCU usage:
160  * The tun_file and tun_struct are loosely coupled, the pointer from one to the
161  * other can only be read while rcu_read_lock or rtnl_lock is held.
162  */
163 struct tun_file {
164 	struct sock sk;
165 	struct socket socket;
166 	struct socket_wq wq;
167 	struct tun_struct __rcu *tun;
168 	struct fasync_struct *fasync;
169 	/* only used for fasnyc */
170 	unsigned int flags;
171 	union {
172 		u16 queue_index;
173 		unsigned int ifindex;
174 	};
175 	struct list_head next;
176 	struct tun_struct *detached;
177 	struct skb_array tx_array;
178 };
179 
180 struct tun_flow_entry {
181 	struct hlist_node hash_link;
182 	struct rcu_head rcu;
183 	struct tun_struct *tun;
184 
185 	u32 rxhash;
186 	u32 rps_rxhash;
187 	int queue_index;
188 	unsigned long updated;
189 };
190 
191 #define TUN_NUM_FLOW_ENTRIES 1024
192 
193 /* Since the socket were moved to tun_file, to preserve the behavior of persist
194  * device, socket filter, sndbuf and vnet header size were restore when the
195  * file were attached to a persist device.
196  */
197 struct tun_struct {
198 	struct tun_file __rcu	*tfiles[MAX_TAP_QUEUES];
199 	unsigned int            numqueues;
200 	unsigned int 		flags;
201 	kuid_t			owner;
202 	kgid_t			group;
203 
204 	struct net_device	*dev;
205 	netdev_features_t	set_features;
206 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
207 			  NETIF_F_TSO6)
208 
209 	int			align;
210 	int			vnet_hdr_sz;
211 	int			sndbuf;
212 	struct tap_filter	txflt;
213 	struct sock_fprog	fprog;
214 	/* protected by rtnl lock */
215 	bool			filter_attached;
216 #ifdef TUN_DEBUG
217 	int debug;
218 #endif
219 	spinlock_t lock;
220 	struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
221 	struct timer_list flow_gc_timer;
222 	unsigned long ageing_time;
223 	unsigned int numdisabled;
224 	struct list_head disabled;
225 	void *security;
226 	u32 flow_count;
227 	u32 rx_batched;
228 	struct tun_pcpu_stats __percpu *pcpu_stats;
229 	struct bpf_prog __rcu *xdp_prog;
230 };
231 
232 #ifdef CONFIG_TUN_VNET_CROSS_LE
233 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
234 {
235 	return tun->flags & TUN_VNET_BE ? false :
236 		virtio_legacy_is_little_endian();
237 }
238 
239 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
240 {
241 	int be = !!(tun->flags & TUN_VNET_BE);
242 
243 	if (put_user(be, argp))
244 		return -EFAULT;
245 
246 	return 0;
247 }
248 
249 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
250 {
251 	int be;
252 
253 	if (get_user(be, argp))
254 		return -EFAULT;
255 
256 	if (be)
257 		tun->flags |= TUN_VNET_BE;
258 	else
259 		tun->flags &= ~TUN_VNET_BE;
260 
261 	return 0;
262 }
263 #else
264 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
265 {
266 	return virtio_legacy_is_little_endian();
267 }
268 
269 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
270 {
271 	return -EINVAL;
272 }
273 
274 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
275 {
276 	return -EINVAL;
277 }
278 #endif /* CONFIG_TUN_VNET_CROSS_LE */
279 
280 static inline bool tun_is_little_endian(struct tun_struct *tun)
281 {
282 	return tun->flags & TUN_VNET_LE ||
283 		tun_legacy_is_little_endian(tun);
284 }
285 
286 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
287 {
288 	return __virtio16_to_cpu(tun_is_little_endian(tun), val);
289 }
290 
291 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
292 {
293 	return __cpu_to_virtio16(tun_is_little_endian(tun), val);
294 }
295 
296 static inline u32 tun_hashfn(u32 rxhash)
297 {
298 	return rxhash & 0x3ff;
299 }
300 
301 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
302 {
303 	struct tun_flow_entry *e;
304 
305 	hlist_for_each_entry_rcu(e, head, hash_link) {
306 		if (e->rxhash == rxhash)
307 			return e;
308 	}
309 	return NULL;
310 }
311 
312 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
313 					      struct hlist_head *head,
314 					      u32 rxhash, u16 queue_index)
315 {
316 	struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
317 
318 	if (e) {
319 		tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
320 			  rxhash, queue_index);
321 		e->updated = jiffies;
322 		e->rxhash = rxhash;
323 		e->rps_rxhash = 0;
324 		e->queue_index = queue_index;
325 		e->tun = tun;
326 		hlist_add_head_rcu(&e->hash_link, head);
327 		++tun->flow_count;
328 	}
329 	return e;
330 }
331 
332 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
333 {
334 	tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
335 		  e->rxhash, e->queue_index);
336 	hlist_del_rcu(&e->hash_link);
337 	kfree_rcu(e, rcu);
338 	--tun->flow_count;
339 }
340 
341 static void tun_flow_flush(struct tun_struct *tun)
342 {
343 	int i;
344 
345 	spin_lock_bh(&tun->lock);
346 	for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
347 		struct tun_flow_entry *e;
348 		struct hlist_node *n;
349 
350 		hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
351 			tun_flow_delete(tun, e);
352 	}
353 	spin_unlock_bh(&tun->lock);
354 }
355 
356 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
357 {
358 	int i;
359 
360 	spin_lock_bh(&tun->lock);
361 	for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
362 		struct tun_flow_entry *e;
363 		struct hlist_node *n;
364 
365 		hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
366 			if (e->queue_index == queue_index)
367 				tun_flow_delete(tun, e);
368 		}
369 	}
370 	spin_unlock_bh(&tun->lock);
371 }
372 
373 static void tun_flow_cleanup(unsigned long data)
374 {
375 	struct tun_struct *tun = (struct tun_struct *)data;
376 	unsigned long delay = tun->ageing_time;
377 	unsigned long next_timer = jiffies + delay;
378 	unsigned long count = 0;
379 	int i;
380 
381 	tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
382 
383 	spin_lock_bh(&tun->lock);
384 	for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
385 		struct tun_flow_entry *e;
386 		struct hlist_node *n;
387 
388 		hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
389 			unsigned long this_timer;
390 			count++;
391 			this_timer = e->updated + delay;
392 			if (time_before_eq(this_timer, jiffies))
393 				tun_flow_delete(tun, e);
394 			else if (time_before(this_timer, next_timer))
395 				next_timer = this_timer;
396 		}
397 	}
398 
399 	if (count)
400 		mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
401 	spin_unlock_bh(&tun->lock);
402 }
403 
404 static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
405 			    struct tun_file *tfile)
406 {
407 	struct hlist_head *head;
408 	struct tun_flow_entry *e;
409 	unsigned long delay = tun->ageing_time;
410 	u16 queue_index = tfile->queue_index;
411 
412 	if (!rxhash)
413 		return;
414 	else
415 		head = &tun->flows[tun_hashfn(rxhash)];
416 
417 	rcu_read_lock();
418 
419 	/* We may get a very small possibility of OOO during switching, not
420 	 * worth to optimize.*/
421 	if (tun->numqueues == 1 || tfile->detached)
422 		goto unlock;
423 
424 	e = tun_flow_find(head, rxhash);
425 	if (likely(e)) {
426 		/* TODO: keep queueing to old queue until it's empty? */
427 		e->queue_index = queue_index;
428 		e->updated = jiffies;
429 		sock_rps_record_flow_hash(e->rps_rxhash);
430 	} else {
431 		spin_lock_bh(&tun->lock);
432 		if (!tun_flow_find(head, rxhash) &&
433 		    tun->flow_count < MAX_TAP_FLOWS)
434 			tun_flow_create(tun, head, rxhash, queue_index);
435 
436 		if (!timer_pending(&tun->flow_gc_timer))
437 			mod_timer(&tun->flow_gc_timer,
438 				  round_jiffies_up(jiffies + delay));
439 		spin_unlock_bh(&tun->lock);
440 	}
441 
442 unlock:
443 	rcu_read_unlock();
444 }
445 
446 /**
447  * Save the hash received in the stack receive path and update the
448  * flow_hash table accordingly.
449  */
450 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
451 {
452 	if (unlikely(e->rps_rxhash != hash))
453 		e->rps_rxhash = hash;
454 }
455 
456 /* We try to identify a flow through its rxhash first. The reason that
457  * we do not check rxq no. is because some cards(e.g 82599), chooses
458  * the rxq based on the txq where the last packet of the flow comes. As
459  * the userspace application move between processors, we may get a
460  * different rxq no. here. If we could not get rxhash, then we would
461  * hope the rxq no. may help here.
462  */
463 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
464 			    void *accel_priv, select_queue_fallback_t fallback)
465 {
466 	struct tun_struct *tun = netdev_priv(dev);
467 	struct tun_flow_entry *e;
468 	u32 txq = 0;
469 	u32 numqueues = 0;
470 
471 	rcu_read_lock();
472 	numqueues = ACCESS_ONCE(tun->numqueues);
473 
474 	txq = __skb_get_hash_symmetric(skb);
475 	if (txq) {
476 		e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
477 		if (e) {
478 			tun_flow_save_rps_rxhash(e, txq);
479 			txq = e->queue_index;
480 		} else
481 			/* use multiply and shift instead of expensive divide */
482 			txq = ((u64)txq * numqueues) >> 32;
483 	} else if (likely(skb_rx_queue_recorded(skb))) {
484 		txq = skb_get_rx_queue(skb);
485 		while (unlikely(txq >= numqueues))
486 			txq -= numqueues;
487 	}
488 
489 	rcu_read_unlock();
490 	return txq;
491 }
492 
493 static inline bool tun_not_capable(struct tun_struct *tun)
494 {
495 	const struct cred *cred = current_cred();
496 	struct net *net = dev_net(tun->dev);
497 
498 	return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
499 		  (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
500 		!ns_capable(net->user_ns, CAP_NET_ADMIN);
501 }
502 
503 static void tun_set_real_num_queues(struct tun_struct *tun)
504 {
505 	netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
506 	netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
507 }
508 
509 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
510 {
511 	tfile->detached = tun;
512 	list_add_tail(&tfile->next, &tun->disabled);
513 	++tun->numdisabled;
514 }
515 
516 static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
517 {
518 	struct tun_struct *tun = tfile->detached;
519 
520 	tfile->detached = NULL;
521 	list_del_init(&tfile->next);
522 	--tun->numdisabled;
523 	return tun;
524 }
525 
526 static void tun_queue_purge(struct tun_file *tfile)
527 {
528 	struct sk_buff *skb;
529 
530 	while ((skb = skb_array_consume(&tfile->tx_array)) != NULL)
531 		kfree_skb(skb);
532 
533 	skb_queue_purge(&tfile->sk.sk_write_queue);
534 	skb_queue_purge(&tfile->sk.sk_error_queue);
535 }
536 
537 static void __tun_detach(struct tun_file *tfile, bool clean)
538 {
539 	struct tun_file *ntfile;
540 	struct tun_struct *tun;
541 
542 	tun = rtnl_dereference(tfile->tun);
543 
544 	if (tun && !tfile->detached) {
545 		u16 index = tfile->queue_index;
546 		BUG_ON(index >= tun->numqueues);
547 
548 		rcu_assign_pointer(tun->tfiles[index],
549 				   tun->tfiles[tun->numqueues - 1]);
550 		ntfile = rtnl_dereference(tun->tfiles[index]);
551 		ntfile->queue_index = index;
552 
553 		--tun->numqueues;
554 		if (clean) {
555 			RCU_INIT_POINTER(tfile->tun, NULL);
556 			sock_put(&tfile->sk);
557 		} else
558 			tun_disable_queue(tun, tfile);
559 
560 		synchronize_net();
561 		tun_flow_delete_by_queue(tun, tun->numqueues + 1);
562 		/* Drop read queue */
563 		tun_queue_purge(tfile);
564 		tun_set_real_num_queues(tun);
565 	} else if (tfile->detached && clean) {
566 		tun = tun_enable_queue(tfile);
567 		sock_put(&tfile->sk);
568 	}
569 
570 	if (clean) {
571 		if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
572 			netif_carrier_off(tun->dev);
573 
574 			if (!(tun->flags & IFF_PERSIST) &&
575 			    tun->dev->reg_state == NETREG_REGISTERED)
576 				unregister_netdevice(tun->dev);
577 		}
578 		if (tun)
579 			skb_array_cleanup(&tfile->tx_array);
580 		sock_put(&tfile->sk);
581 	}
582 }
583 
584 static void tun_detach(struct tun_file *tfile, bool clean)
585 {
586 	rtnl_lock();
587 	__tun_detach(tfile, clean);
588 	rtnl_unlock();
589 }
590 
591 static void tun_detach_all(struct net_device *dev)
592 {
593 	struct tun_struct *tun = netdev_priv(dev);
594 	struct bpf_prog *xdp_prog = rtnl_dereference(tun->xdp_prog);
595 	struct tun_file *tfile, *tmp;
596 	int i, n = tun->numqueues;
597 
598 	for (i = 0; i < n; i++) {
599 		tfile = rtnl_dereference(tun->tfiles[i]);
600 		BUG_ON(!tfile);
601 		tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
602 		tfile->socket.sk->sk_data_ready(tfile->socket.sk);
603 		RCU_INIT_POINTER(tfile->tun, NULL);
604 		--tun->numqueues;
605 	}
606 	list_for_each_entry(tfile, &tun->disabled, next) {
607 		tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
608 		tfile->socket.sk->sk_data_ready(tfile->socket.sk);
609 		RCU_INIT_POINTER(tfile->tun, NULL);
610 	}
611 	BUG_ON(tun->numqueues != 0);
612 
613 	synchronize_net();
614 	for (i = 0; i < n; i++) {
615 		tfile = rtnl_dereference(tun->tfiles[i]);
616 		/* Drop read queue */
617 		tun_queue_purge(tfile);
618 		sock_put(&tfile->sk);
619 	}
620 	list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
621 		tun_enable_queue(tfile);
622 		tun_queue_purge(tfile);
623 		sock_put(&tfile->sk);
624 	}
625 	BUG_ON(tun->numdisabled != 0);
626 
627 	if (xdp_prog)
628 		bpf_prog_put(xdp_prog);
629 
630 	if (tun->flags & IFF_PERSIST)
631 		module_put(THIS_MODULE);
632 }
633 
634 static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter)
635 {
636 	struct tun_file *tfile = file->private_data;
637 	struct net_device *dev = tun->dev;
638 	int err;
639 
640 	err = security_tun_dev_attach(tfile->socket.sk, tun->security);
641 	if (err < 0)
642 		goto out;
643 
644 	err = -EINVAL;
645 	if (rtnl_dereference(tfile->tun) && !tfile->detached)
646 		goto out;
647 
648 	err = -EBUSY;
649 	if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
650 		goto out;
651 
652 	err = -E2BIG;
653 	if (!tfile->detached &&
654 	    tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
655 		goto out;
656 
657 	err = 0;
658 
659 	/* Re-attach the filter to persist device */
660 	if (!skip_filter && (tun->filter_attached == true)) {
661 		lock_sock(tfile->socket.sk);
662 		err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
663 		release_sock(tfile->socket.sk);
664 		if (!err)
665 			goto out;
666 	}
667 
668 	if (!tfile->detached &&
669 	    skb_array_init(&tfile->tx_array, dev->tx_queue_len, GFP_KERNEL)) {
670 		err = -ENOMEM;
671 		goto out;
672 	}
673 
674 	tfile->queue_index = tun->numqueues;
675 	tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
676 	rcu_assign_pointer(tfile->tun, tun);
677 	rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
678 	tun->numqueues++;
679 
680 	if (tfile->detached)
681 		tun_enable_queue(tfile);
682 	else
683 		sock_hold(&tfile->sk);
684 
685 	tun_set_real_num_queues(tun);
686 
687 	/* device is allowed to go away first, so no need to hold extra
688 	 * refcnt.
689 	 */
690 
691 out:
692 	return err;
693 }
694 
695 static struct tun_struct *__tun_get(struct tun_file *tfile)
696 {
697 	struct tun_struct *tun;
698 
699 	rcu_read_lock();
700 	tun = rcu_dereference(tfile->tun);
701 	if (tun)
702 		dev_hold(tun->dev);
703 	rcu_read_unlock();
704 
705 	return tun;
706 }
707 
708 static struct tun_struct *tun_get(struct file *file)
709 {
710 	return __tun_get(file->private_data);
711 }
712 
713 static void tun_put(struct tun_struct *tun)
714 {
715 	dev_put(tun->dev);
716 }
717 
718 /* TAP filtering */
719 static void addr_hash_set(u32 *mask, const u8 *addr)
720 {
721 	int n = ether_crc(ETH_ALEN, addr) >> 26;
722 	mask[n >> 5] |= (1 << (n & 31));
723 }
724 
725 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
726 {
727 	int n = ether_crc(ETH_ALEN, addr) >> 26;
728 	return mask[n >> 5] & (1 << (n & 31));
729 }
730 
731 static int update_filter(struct tap_filter *filter, void __user *arg)
732 {
733 	struct { u8 u[ETH_ALEN]; } *addr;
734 	struct tun_filter uf;
735 	int err, alen, n, nexact;
736 
737 	if (copy_from_user(&uf, arg, sizeof(uf)))
738 		return -EFAULT;
739 
740 	if (!uf.count) {
741 		/* Disabled */
742 		filter->count = 0;
743 		return 0;
744 	}
745 
746 	alen = ETH_ALEN * uf.count;
747 	addr = memdup_user(arg + sizeof(uf), alen);
748 	if (IS_ERR(addr))
749 		return PTR_ERR(addr);
750 
751 	/* The filter is updated without holding any locks. Which is
752 	 * perfectly safe. We disable it first and in the worst
753 	 * case we'll accept a few undesired packets. */
754 	filter->count = 0;
755 	wmb();
756 
757 	/* Use first set of addresses as an exact filter */
758 	for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
759 		memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
760 
761 	nexact = n;
762 
763 	/* Remaining multicast addresses are hashed,
764 	 * unicast will leave the filter disabled. */
765 	memset(filter->mask, 0, sizeof(filter->mask));
766 	for (; n < uf.count; n++) {
767 		if (!is_multicast_ether_addr(addr[n].u)) {
768 			err = 0; /* no filter */
769 			goto free_addr;
770 		}
771 		addr_hash_set(filter->mask, addr[n].u);
772 	}
773 
774 	/* For ALLMULTI just set the mask to all ones.
775 	 * This overrides the mask populated above. */
776 	if ((uf.flags & TUN_FLT_ALLMULTI))
777 		memset(filter->mask, ~0, sizeof(filter->mask));
778 
779 	/* Now enable the filter */
780 	wmb();
781 	filter->count = nexact;
782 
783 	/* Return the number of exact filters */
784 	err = nexact;
785 free_addr:
786 	kfree(addr);
787 	return err;
788 }
789 
790 /* Returns: 0 - drop, !=0 - accept */
791 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
792 {
793 	/* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
794 	 * at this point. */
795 	struct ethhdr *eh = (struct ethhdr *) skb->data;
796 	int i;
797 
798 	/* Exact match */
799 	for (i = 0; i < filter->count; i++)
800 		if (ether_addr_equal(eh->h_dest, filter->addr[i]))
801 			return 1;
802 
803 	/* Inexact match (multicast only) */
804 	if (is_multicast_ether_addr(eh->h_dest))
805 		return addr_hash_test(filter->mask, eh->h_dest);
806 
807 	return 0;
808 }
809 
810 /*
811  * Checks whether the packet is accepted or not.
812  * Returns: 0 - drop, !=0 - accept
813  */
814 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
815 {
816 	if (!filter->count)
817 		return 1;
818 
819 	return run_filter(filter, skb);
820 }
821 
822 /* Network device part of the driver */
823 
824 static const struct ethtool_ops tun_ethtool_ops;
825 
826 /* Net device detach from fd. */
827 static void tun_net_uninit(struct net_device *dev)
828 {
829 	tun_detach_all(dev);
830 }
831 
832 /* Net device open. */
833 static int tun_net_open(struct net_device *dev)
834 {
835 	struct tun_struct *tun = netdev_priv(dev);
836 	int i;
837 
838 	netif_tx_start_all_queues(dev);
839 
840 	for (i = 0; i < tun->numqueues; i++) {
841 		struct tun_file *tfile;
842 
843 		tfile = rtnl_dereference(tun->tfiles[i]);
844 		tfile->socket.sk->sk_write_space(tfile->socket.sk);
845 	}
846 
847 	return 0;
848 }
849 
850 /* Net device close. */
851 static int tun_net_close(struct net_device *dev)
852 {
853 	netif_tx_stop_all_queues(dev);
854 	return 0;
855 }
856 
857 /* Net device start xmit */
858 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
859 {
860 	struct tun_struct *tun = netdev_priv(dev);
861 	int txq = skb->queue_mapping;
862 	struct tun_file *tfile;
863 	u32 numqueues = 0;
864 
865 	rcu_read_lock();
866 	tfile = rcu_dereference(tun->tfiles[txq]);
867 	numqueues = ACCESS_ONCE(tun->numqueues);
868 
869 	/* Drop packet if interface is not attached */
870 	if (txq >= numqueues)
871 		goto drop;
872 
873 #ifdef CONFIG_RPS
874 	if (numqueues == 1 && static_key_false(&rps_needed)) {
875 		/* Select queue was not called for the skbuff, so we extract the
876 		 * RPS hash and save it into the flow_table here.
877 		 */
878 		__u32 rxhash;
879 
880 		rxhash = __skb_get_hash_symmetric(skb);
881 		if (rxhash) {
882 			struct tun_flow_entry *e;
883 			e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)],
884 					rxhash);
885 			if (e)
886 				tun_flow_save_rps_rxhash(e, rxhash);
887 		}
888 	}
889 #endif
890 
891 	tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
892 
893 	BUG_ON(!tfile);
894 
895 	/* Drop if the filter does not like it.
896 	 * This is a noop if the filter is disabled.
897 	 * Filter can be enabled only for the TAP devices. */
898 	if (!check_filter(&tun->txflt, skb))
899 		goto drop;
900 
901 	if (tfile->socket.sk->sk_filter &&
902 	    sk_filter(tfile->socket.sk, skb))
903 		goto drop;
904 
905 	if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC)))
906 		goto drop;
907 
908 	skb_tx_timestamp(skb);
909 
910 	/* Orphan the skb - required as we might hang on to it
911 	 * for indefinite time.
912 	 */
913 	skb_orphan(skb);
914 
915 	nf_reset(skb);
916 
917 	if (skb_array_produce(&tfile->tx_array, skb))
918 		goto drop;
919 
920 	/* Notify and wake up reader process */
921 	if (tfile->flags & TUN_FASYNC)
922 		kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
923 	tfile->socket.sk->sk_data_ready(tfile->socket.sk);
924 
925 	rcu_read_unlock();
926 	return NETDEV_TX_OK;
927 
928 drop:
929 	this_cpu_inc(tun->pcpu_stats->tx_dropped);
930 	skb_tx_error(skb);
931 	kfree_skb(skb);
932 	rcu_read_unlock();
933 	return NET_XMIT_DROP;
934 }
935 
936 static void tun_net_mclist(struct net_device *dev)
937 {
938 	/*
939 	 * This callback is supposed to deal with mc filter in
940 	 * _rx_ path and has nothing to do with the _tx_ path.
941 	 * In rx path we always accept everything userspace gives us.
942 	 */
943 }
944 
945 static netdev_features_t tun_net_fix_features(struct net_device *dev,
946 	netdev_features_t features)
947 {
948 	struct tun_struct *tun = netdev_priv(dev);
949 
950 	return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
951 }
952 #ifdef CONFIG_NET_POLL_CONTROLLER
953 static void tun_poll_controller(struct net_device *dev)
954 {
955 	/*
956 	 * Tun only receives frames when:
957 	 * 1) the char device endpoint gets data from user space
958 	 * 2) the tun socket gets a sendmsg call from user space
959 	 * Since both of those are synchronous operations, we are guaranteed
960 	 * never to have pending data when we poll for it
961 	 * so there is nothing to do here but return.
962 	 * We need this though so netpoll recognizes us as an interface that
963 	 * supports polling, which enables bridge devices in virt setups to
964 	 * still use netconsole
965 	 */
966 	return;
967 }
968 #endif
969 
970 static void tun_set_headroom(struct net_device *dev, int new_hr)
971 {
972 	struct tun_struct *tun = netdev_priv(dev);
973 
974 	if (new_hr < NET_SKB_PAD)
975 		new_hr = NET_SKB_PAD;
976 
977 	tun->align = new_hr;
978 }
979 
980 static void
981 tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
982 {
983 	u32 rx_dropped = 0, tx_dropped = 0, rx_frame_errors = 0;
984 	struct tun_struct *tun = netdev_priv(dev);
985 	struct tun_pcpu_stats *p;
986 	int i;
987 
988 	for_each_possible_cpu(i) {
989 		u64 rxpackets, rxbytes, txpackets, txbytes;
990 		unsigned int start;
991 
992 		p = per_cpu_ptr(tun->pcpu_stats, i);
993 		do {
994 			start = u64_stats_fetch_begin(&p->syncp);
995 			rxpackets	= p->rx_packets;
996 			rxbytes		= p->rx_bytes;
997 			txpackets	= p->tx_packets;
998 			txbytes		= p->tx_bytes;
999 		} while (u64_stats_fetch_retry(&p->syncp, start));
1000 
1001 		stats->rx_packets	+= rxpackets;
1002 		stats->rx_bytes		+= rxbytes;
1003 		stats->tx_packets	+= txpackets;
1004 		stats->tx_bytes		+= txbytes;
1005 
1006 		/* u32 counters */
1007 		rx_dropped	+= p->rx_dropped;
1008 		rx_frame_errors	+= p->rx_frame_errors;
1009 		tx_dropped	+= p->tx_dropped;
1010 	}
1011 	stats->rx_dropped  = rx_dropped;
1012 	stats->rx_frame_errors = rx_frame_errors;
1013 	stats->tx_dropped = tx_dropped;
1014 }
1015 
1016 static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1017 		       struct netlink_ext_ack *extack)
1018 {
1019 	struct tun_struct *tun = netdev_priv(dev);
1020 	struct bpf_prog *old_prog;
1021 
1022 	old_prog = rtnl_dereference(tun->xdp_prog);
1023 	rcu_assign_pointer(tun->xdp_prog, prog);
1024 	if (old_prog)
1025 		bpf_prog_put(old_prog);
1026 
1027 	return 0;
1028 }
1029 
1030 static u32 tun_xdp_query(struct net_device *dev)
1031 {
1032 	struct tun_struct *tun = netdev_priv(dev);
1033 	const struct bpf_prog *xdp_prog;
1034 
1035 	xdp_prog = rtnl_dereference(tun->xdp_prog);
1036 	if (xdp_prog)
1037 		return xdp_prog->aux->id;
1038 
1039 	return 0;
1040 }
1041 
1042 static int tun_xdp(struct net_device *dev, struct netdev_xdp *xdp)
1043 {
1044 	switch (xdp->command) {
1045 	case XDP_SETUP_PROG:
1046 		return tun_xdp_set(dev, xdp->prog, xdp->extack);
1047 	case XDP_QUERY_PROG:
1048 		xdp->prog_id = tun_xdp_query(dev);
1049 		xdp->prog_attached = !!xdp->prog_id;
1050 		return 0;
1051 	default:
1052 		return -EINVAL;
1053 	}
1054 }
1055 
1056 static const struct net_device_ops tun_netdev_ops = {
1057 	.ndo_uninit		= tun_net_uninit,
1058 	.ndo_open		= tun_net_open,
1059 	.ndo_stop		= tun_net_close,
1060 	.ndo_start_xmit		= tun_net_xmit,
1061 	.ndo_fix_features	= tun_net_fix_features,
1062 	.ndo_select_queue	= tun_select_queue,
1063 #ifdef CONFIG_NET_POLL_CONTROLLER
1064 	.ndo_poll_controller	= tun_poll_controller,
1065 #endif
1066 	.ndo_set_rx_headroom	= tun_set_headroom,
1067 	.ndo_get_stats64	= tun_net_get_stats64,
1068 };
1069 
1070 static const struct net_device_ops tap_netdev_ops = {
1071 	.ndo_uninit		= tun_net_uninit,
1072 	.ndo_open		= tun_net_open,
1073 	.ndo_stop		= tun_net_close,
1074 	.ndo_start_xmit		= tun_net_xmit,
1075 	.ndo_fix_features	= tun_net_fix_features,
1076 	.ndo_set_rx_mode	= tun_net_mclist,
1077 	.ndo_set_mac_address	= eth_mac_addr,
1078 	.ndo_validate_addr	= eth_validate_addr,
1079 	.ndo_select_queue	= tun_select_queue,
1080 #ifdef CONFIG_NET_POLL_CONTROLLER
1081 	.ndo_poll_controller	= tun_poll_controller,
1082 #endif
1083 	.ndo_features_check	= passthru_features_check,
1084 	.ndo_set_rx_headroom	= tun_set_headroom,
1085 	.ndo_get_stats64	= tun_net_get_stats64,
1086 	.ndo_xdp		= tun_xdp,
1087 };
1088 
1089 static void tun_flow_init(struct tun_struct *tun)
1090 {
1091 	int i;
1092 
1093 	for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1094 		INIT_HLIST_HEAD(&tun->flows[i]);
1095 
1096 	tun->ageing_time = TUN_FLOW_EXPIRE;
1097 	setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun);
1098 	mod_timer(&tun->flow_gc_timer,
1099 		  round_jiffies_up(jiffies + tun->ageing_time));
1100 }
1101 
1102 static void tun_flow_uninit(struct tun_struct *tun)
1103 {
1104 	del_timer_sync(&tun->flow_gc_timer);
1105 	tun_flow_flush(tun);
1106 }
1107 
1108 #define MIN_MTU 68
1109 #define MAX_MTU 65535
1110 
1111 /* Initialize net device. */
1112 static void tun_net_init(struct net_device *dev)
1113 {
1114 	struct tun_struct *tun = netdev_priv(dev);
1115 
1116 	switch (tun->flags & TUN_TYPE_MASK) {
1117 	case IFF_TUN:
1118 		dev->netdev_ops = &tun_netdev_ops;
1119 
1120 		/* Point-to-Point TUN Device */
1121 		dev->hard_header_len = 0;
1122 		dev->addr_len = 0;
1123 		dev->mtu = 1500;
1124 
1125 		/* Zero header length */
1126 		dev->type = ARPHRD_NONE;
1127 		dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1128 		break;
1129 
1130 	case IFF_TAP:
1131 		dev->netdev_ops = &tap_netdev_ops;
1132 		/* Ethernet TAP Device */
1133 		ether_setup(dev);
1134 		dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1135 		dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1136 
1137 		eth_hw_addr_random(dev);
1138 
1139 		break;
1140 	}
1141 
1142 	dev->min_mtu = MIN_MTU;
1143 	dev->max_mtu = MAX_MTU - dev->hard_header_len;
1144 }
1145 
1146 /* Character device part */
1147 
1148 /* Poll */
1149 static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
1150 {
1151 	struct tun_file *tfile = file->private_data;
1152 	struct tun_struct *tun = __tun_get(tfile);
1153 	struct sock *sk;
1154 	unsigned int mask = 0;
1155 
1156 	if (!tun)
1157 		return POLLERR;
1158 
1159 	sk = tfile->socket.sk;
1160 
1161 	tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
1162 
1163 	poll_wait(file, sk_sleep(sk), wait);
1164 
1165 	if (!skb_array_empty(&tfile->tx_array))
1166 		mask |= POLLIN | POLLRDNORM;
1167 
1168 	if (tun->dev->flags & IFF_UP &&
1169 	    (sock_writeable(sk) ||
1170 	     (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1171 	      sock_writeable(sk))))
1172 		mask |= POLLOUT | POLLWRNORM;
1173 
1174 	if (tun->dev->reg_state != NETREG_REGISTERED)
1175 		mask = POLLERR;
1176 
1177 	tun_put(tun);
1178 	return mask;
1179 }
1180 
1181 /* prepad is the amount to reserve at front.  len is length after that.
1182  * linear is a hint as to how much to copy (usually headers). */
1183 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1184 				     size_t prepad, size_t len,
1185 				     size_t linear, int noblock)
1186 {
1187 	struct sock *sk = tfile->socket.sk;
1188 	struct sk_buff *skb;
1189 	int err;
1190 
1191 	/* Under a page?  Don't bother with paged skb. */
1192 	if (prepad + len < PAGE_SIZE || !linear)
1193 		linear = len;
1194 
1195 	skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1196 				   &err, 0);
1197 	if (!skb)
1198 		return ERR_PTR(err);
1199 
1200 	skb_reserve(skb, prepad);
1201 	skb_put(skb, linear);
1202 	skb->data_len = len - linear;
1203 	skb->len += len - linear;
1204 
1205 	return skb;
1206 }
1207 
1208 static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile,
1209 			   struct sk_buff *skb, int more)
1210 {
1211 	struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1212 	struct sk_buff_head process_queue;
1213 	u32 rx_batched = tun->rx_batched;
1214 	bool rcv = false;
1215 
1216 	if (!rx_batched || (!more && skb_queue_empty(queue))) {
1217 		local_bh_disable();
1218 		netif_receive_skb(skb);
1219 		local_bh_enable();
1220 		return;
1221 	}
1222 
1223 	spin_lock(&queue->lock);
1224 	if (!more || skb_queue_len(queue) == rx_batched) {
1225 		__skb_queue_head_init(&process_queue);
1226 		skb_queue_splice_tail_init(queue, &process_queue);
1227 		rcv = true;
1228 	} else {
1229 		__skb_queue_tail(queue, skb);
1230 	}
1231 	spin_unlock(&queue->lock);
1232 
1233 	if (rcv) {
1234 		struct sk_buff *nskb;
1235 
1236 		local_bh_disable();
1237 		while ((nskb = __skb_dequeue(&process_queue)))
1238 			netif_receive_skb(nskb);
1239 		netif_receive_skb(skb);
1240 		local_bh_enable();
1241 	}
1242 }
1243 
1244 static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile,
1245 			      int len, int noblock, bool zerocopy)
1246 {
1247 	if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
1248 		return false;
1249 
1250 	if (tfile->socket.sk->sk_sndbuf != INT_MAX)
1251 		return false;
1252 
1253 	if (!noblock)
1254 		return false;
1255 
1256 	if (zerocopy)
1257 		return false;
1258 
1259 	if (SKB_DATA_ALIGN(len + TUN_RX_PAD) +
1260 	    SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
1261 		return false;
1262 
1263 	return true;
1264 }
1265 
1266 static struct sk_buff *tun_build_skb(struct tun_struct *tun,
1267 				     struct tun_file *tfile,
1268 				     struct iov_iter *from,
1269 				     struct virtio_net_hdr *hdr,
1270 				     int len, int *skb_xdp)
1271 {
1272 	struct page_frag *alloc_frag = &current->task_frag;
1273 	struct sk_buff *skb;
1274 	struct bpf_prog *xdp_prog;
1275 	int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1276 	unsigned int delta = 0;
1277 	char *buf;
1278 	size_t copied;
1279 	bool xdp_xmit = false;
1280 	int err, pad = TUN_RX_PAD;
1281 
1282 	rcu_read_lock();
1283 	xdp_prog = rcu_dereference(tun->xdp_prog);
1284 	if (xdp_prog)
1285 		pad += TUN_HEADROOM;
1286 	buflen += SKB_DATA_ALIGN(len + pad);
1287 	rcu_read_unlock();
1288 
1289 	if (unlikely(!skb_page_frag_refill(buflen, alloc_frag, GFP_KERNEL)))
1290 		return ERR_PTR(-ENOMEM);
1291 
1292 	buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
1293 	copied = copy_page_from_iter(alloc_frag->page,
1294 				     alloc_frag->offset + pad,
1295 				     len, from);
1296 	if (copied != len)
1297 		return ERR_PTR(-EFAULT);
1298 
1299 	/* There's a small window that XDP may be set after the check
1300 	 * of xdp_prog above, this should be rare and for simplicity
1301 	 * we do XDP on skb in case the headroom is not enough.
1302 	 */
1303 	if (hdr->gso_type || !xdp_prog)
1304 		*skb_xdp = 1;
1305 	else
1306 		*skb_xdp = 0;
1307 
1308 	rcu_read_lock();
1309 	xdp_prog = rcu_dereference(tun->xdp_prog);
1310 	if (xdp_prog && !*skb_xdp) {
1311 		struct xdp_buff xdp;
1312 		void *orig_data;
1313 		u32 act;
1314 
1315 		xdp.data_hard_start = buf;
1316 		xdp.data = buf + pad;
1317 		xdp.data_end = xdp.data + len;
1318 		orig_data = xdp.data;
1319 		act = bpf_prog_run_xdp(xdp_prog, &xdp);
1320 
1321 		switch (act) {
1322 		case XDP_REDIRECT:
1323 			get_page(alloc_frag->page);
1324 			alloc_frag->offset += buflen;
1325 			err = xdp_do_redirect(tun->dev, &xdp, xdp_prog);
1326 			if (err)
1327 				goto err_redirect;
1328 			return NULL;
1329 		case XDP_TX:
1330 			xdp_xmit = true;
1331 			/* fall through */
1332 		case XDP_PASS:
1333 			delta = orig_data - xdp.data;
1334 			break;
1335 		default:
1336 			bpf_warn_invalid_xdp_action(act);
1337 			/* fall through */
1338 		case XDP_ABORTED:
1339 			trace_xdp_exception(tun->dev, xdp_prog, act);
1340 			/* fall through */
1341 		case XDP_DROP:
1342 			goto err_xdp;
1343 		}
1344 	}
1345 
1346 	skb = build_skb(buf, buflen);
1347 	if (!skb) {
1348 		rcu_read_unlock();
1349 		return ERR_PTR(-ENOMEM);
1350 	}
1351 
1352 	skb_reserve(skb, pad - delta);
1353 	skb_put(skb, len + delta);
1354 	get_page(alloc_frag->page);
1355 	alloc_frag->offset += buflen;
1356 
1357 	if (xdp_xmit) {
1358 		skb->dev = tun->dev;
1359 		generic_xdp_tx(skb, xdp_prog);
1360 		rcu_read_lock();
1361 		return NULL;
1362 	}
1363 
1364 	rcu_read_unlock();
1365 
1366 	return skb;
1367 
1368 err_redirect:
1369 	put_page(alloc_frag->page);
1370 err_xdp:
1371 	rcu_read_unlock();
1372 	this_cpu_inc(tun->pcpu_stats->rx_dropped);
1373 	return NULL;
1374 }
1375 
1376 /* Get packet from user space buffer */
1377 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1378 			    void *msg_control, struct iov_iter *from,
1379 			    int noblock, bool more)
1380 {
1381 	struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1382 	struct sk_buff *skb;
1383 	size_t total_len = iov_iter_count(from);
1384 	size_t len = total_len, align = tun->align, linear;
1385 	struct virtio_net_hdr gso = { 0 };
1386 	struct tun_pcpu_stats *stats;
1387 	int good_linear;
1388 	int copylen;
1389 	bool zerocopy = false;
1390 	int err;
1391 	u32 rxhash;
1392 	int skb_xdp = 1;
1393 
1394 	if (!(tun->dev->flags & IFF_UP))
1395 		return -EIO;
1396 
1397 	if (!(tun->flags & IFF_NO_PI)) {
1398 		if (len < sizeof(pi))
1399 			return -EINVAL;
1400 		len -= sizeof(pi);
1401 
1402 		if (!copy_from_iter_full(&pi, sizeof(pi), from))
1403 			return -EFAULT;
1404 	}
1405 
1406 	if (tun->flags & IFF_VNET_HDR) {
1407 		int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1408 
1409 		if (len < vnet_hdr_sz)
1410 			return -EINVAL;
1411 		len -= vnet_hdr_sz;
1412 
1413 		if (!copy_from_iter_full(&gso, sizeof(gso), from))
1414 			return -EFAULT;
1415 
1416 		if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1417 		    tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1418 			gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1419 
1420 		if (tun16_to_cpu(tun, gso.hdr_len) > len)
1421 			return -EINVAL;
1422 		iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1423 	}
1424 
1425 	if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1426 		align += NET_IP_ALIGN;
1427 		if (unlikely(len < ETH_HLEN ||
1428 			     (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1429 			return -EINVAL;
1430 	}
1431 
1432 	good_linear = SKB_MAX_HEAD(align);
1433 
1434 	if (msg_control) {
1435 		struct iov_iter i = *from;
1436 
1437 		/* There are 256 bytes to be copied in skb, so there is
1438 		 * enough room for skb expand head in case it is used.
1439 		 * The rest of the buffer is mapped from userspace.
1440 		 */
1441 		copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1442 		if (copylen > good_linear)
1443 			copylen = good_linear;
1444 		linear = copylen;
1445 		iov_iter_advance(&i, copylen);
1446 		if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1447 			zerocopy = true;
1448 	}
1449 
1450 	if (tun_can_build_skb(tun, tfile, len, noblock, zerocopy)) {
1451 		/* For the packet that is not easy to be processed
1452 		 * (e.g gso or jumbo packet), we will do it at after
1453 		 * skb was created with generic XDP routine.
1454 		 */
1455 		skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp);
1456 		if (IS_ERR(skb)) {
1457 			this_cpu_inc(tun->pcpu_stats->rx_dropped);
1458 			return PTR_ERR(skb);
1459 		}
1460 		if (!skb)
1461 			return total_len;
1462 	} else {
1463 		if (!zerocopy) {
1464 			copylen = len;
1465 			if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1466 				linear = good_linear;
1467 			else
1468 				linear = tun16_to_cpu(tun, gso.hdr_len);
1469 		}
1470 
1471 		skb = tun_alloc_skb(tfile, align, copylen, linear, noblock);
1472 		if (IS_ERR(skb)) {
1473 			if (PTR_ERR(skb) != -EAGAIN)
1474 				this_cpu_inc(tun->pcpu_stats->rx_dropped);
1475 			return PTR_ERR(skb);
1476 		}
1477 
1478 		if (zerocopy)
1479 			err = zerocopy_sg_from_iter(skb, from);
1480 		else
1481 			err = skb_copy_datagram_from_iter(skb, 0, from, len);
1482 
1483 		if (err) {
1484 			this_cpu_inc(tun->pcpu_stats->rx_dropped);
1485 			kfree_skb(skb);
1486 			return -EFAULT;
1487 		}
1488 	}
1489 
1490 	if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1491 		this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
1492 		kfree_skb(skb);
1493 		return -EINVAL;
1494 	}
1495 
1496 	switch (tun->flags & TUN_TYPE_MASK) {
1497 	case IFF_TUN:
1498 		if (tun->flags & IFF_NO_PI) {
1499 			u8 ip_version = skb->len ? (skb->data[0] >> 4) : 0;
1500 
1501 			switch (ip_version) {
1502 			case 4:
1503 				pi.proto = htons(ETH_P_IP);
1504 				break;
1505 			case 6:
1506 				pi.proto = htons(ETH_P_IPV6);
1507 				break;
1508 			default:
1509 				this_cpu_inc(tun->pcpu_stats->rx_dropped);
1510 				kfree_skb(skb);
1511 				return -EINVAL;
1512 			}
1513 		}
1514 
1515 		skb_reset_mac_header(skb);
1516 		skb->protocol = pi.proto;
1517 		skb->dev = tun->dev;
1518 		break;
1519 	case IFF_TAP:
1520 		skb->protocol = eth_type_trans(skb, tun->dev);
1521 		break;
1522 	}
1523 
1524 	/* copy skb_ubuf_info for callback when skb has no error */
1525 	if (zerocopy) {
1526 		skb_shinfo(skb)->destructor_arg = msg_control;
1527 		skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1528 		skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1529 	} else if (msg_control) {
1530 		struct ubuf_info *uarg = msg_control;
1531 		uarg->callback(uarg, false);
1532 	}
1533 
1534 	skb_reset_network_header(skb);
1535 	skb_probe_transport_header(skb, 0);
1536 
1537 	if (skb_xdp) {
1538 		struct bpf_prog *xdp_prog;
1539 		int ret;
1540 
1541 		rcu_read_lock();
1542 		xdp_prog = rcu_dereference(tun->xdp_prog);
1543 		if (xdp_prog) {
1544 			ret = do_xdp_generic(xdp_prog, skb);
1545 			if (ret != XDP_PASS) {
1546 				rcu_read_unlock();
1547 				return total_len;
1548 			}
1549 		}
1550 		rcu_read_unlock();
1551 	}
1552 
1553 	rxhash = __skb_get_hash_symmetric(skb);
1554 #ifndef CONFIG_4KSTACKS
1555 	tun_rx_batched(tun, tfile, skb, more);
1556 #else
1557 	netif_rx_ni(skb);
1558 #endif
1559 
1560 	stats = get_cpu_ptr(tun->pcpu_stats);
1561 	u64_stats_update_begin(&stats->syncp);
1562 	stats->rx_packets++;
1563 	stats->rx_bytes += len;
1564 	u64_stats_update_end(&stats->syncp);
1565 	put_cpu_ptr(stats);
1566 
1567 	tun_flow_update(tun, rxhash, tfile);
1568 	return total_len;
1569 }
1570 
1571 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
1572 {
1573 	struct file *file = iocb->ki_filp;
1574 	struct tun_struct *tun = tun_get(file);
1575 	struct tun_file *tfile = file->private_data;
1576 	ssize_t result;
1577 
1578 	if (!tun)
1579 		return -EBADFD;
1580 
1581 	result = tun_get_user(tun, tfile, NULL, from,
1582 			      file->f_flags & O_NONBLOCK, false);
1583 
1584 	tun_put(tun);
1585 	return result;
1586 }
1587 
1588 /* Put packet to the user space buffer */
1589 static ssize_t tun_put_user(struct tun_struct *tun,
1590 			    struct tun_file *tfile,
1591 			    struct sk_buff *skb,
1592 			    struct iov_iter *iter)
1593 {
1594 	struct tun_pi pi = { 0, skb->protocol };
1595 	struct tun_pcpu_stats *stats;
1596 	ssize_t total;
1597 	int vlan_offset = 0;
1598 	int vlan_hlen = 0;
1599 	int vnet_hdr_sz = 0;
1600 
1601 	if (skb_vlan_tag_present(skb))
1602 		vlan_hlen = VLAN_HLEN;
1603 
1604 	if (tun->flags & IFF_VNET_HDR)
1605 		vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1606 
1607 	total = skb->len + vlan_hlen + vnet_hdr_sz;
1608 
1609 	if (!(tun->flags & IFF_NO_PI)) {
1610 		if (iov_iter_count(iter) < sizeof(pi))
1611 			return -EINVAL;
1612 
1613 		total += sizeof(pi);
1614 		if (iov_iter_count(iter) < total) {
1615 			/* Packet will be striped */
1616 			pi.flags |= TUN_PKT_STRIP;
1617 		}
1618 
1619 		if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
1620 			return -EFAULT;
1621 	}
1622 
1623 	if (vnet_hdr_sz) {
1624 		struct virtio_net_hdr gso;
1625 
1626 		if (iov_iter_count(iter) < vnet_hdr_sz)
1627 			return -EINVAL;
1628 
1629 		if (virtio_net_hdr_from_skb(skb, &gso,
1630 					    tun_is_little_endian(tun), true)) {
1631 			struct skb_shared_info *sinfo = skb_shinfo(skb);
1632 			pr_err("unexpected GSO type: "
1633 			       "0x%x, gso_size %d, hdr_len %d\n",
1634 			       sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
1635 			       tun16_to_cpu(tun, gso.hdr_len));
1636 			print_hex_dump(KERN_ERR, "tun: ",
1637 				       DUMP_PREFIX_NONE,
1638 				       16, 1, skb->head,
1639 				       min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
1640 			WARN_ON_ONCE(1);
1641 			return -EINVAL;
1642 		}
1643 
1644 		if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
1645 			return -EFAULT;
1646 
1647 		iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
1648 	}
1649 
1650 	if (vlan_hlen) {
1651 		int ret;
1652 		struct {
1653 			__be16 h_vlan_proto;
1654 			__be16 h_vlan_TCI;
1655 		} veth;
1656 
1657 		veth.h_vlan_proto = skb->vlan_proto;
1658 		veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
1659 
1660 		vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
1661 
1662 		ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
1663 		if (ret || !iov_iter_count(iter))
1664 			goto done;
1665 
1666 		ret = copy_to_iter(&veth, sizeof(veth), iter);
1667 		if (ret != sizeof(veth) || !iov_iter_count(iter))
1668 			goto done;
1669 	}
1670 
1671 	skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
1672 
1673 done:
1674 	/* caller is in process context, */
1675 	stats = get_cpu_ptr(tun->pcpu_stats);
1676 	u64_stats_update_begin(&stats->syncp);
1677 	stats->tx_packets++;
1678 	stats->tx_bytes += skb->len + vlan_hlen;
1679 	u64_stats_update_end(&stats->syncp);
1680 	put_cpu_ptr(tun->pcpu_stats);
1681 
1682 	return total;
1683 }
1684 
1685 static struct sk_buff *tun_ring_recv(struct tun_file *tfile, int noblock,
1686 				     int *err)
1687 {
1688 	DECLARE_WAITQUEUE(wait, current);
1689 	struct sk_buff *skb = NULL;
1690 	int error = 0;
1691 
1692 	skb = skb_array_consume(&tfile->tx_array);
1693 	if (skb)
1694 		goto out;
1695 	if (noblock) {
1696 		error = -EAGAIN;
1697 		goto out;
1698 	}
1699 
1700 	add_wait_queue(&tfile->wq.wait, &wait);
1701 	current->state = TASK_INTERRUPTIBLE;
1702 
1703 	while (1) {
1704 		skb = skb_array_consume(&tfile->tx_array);
1705 		if (skb)
1706 			break;
1707 		if (signal_pending(current)) {
1708 			error = -ERESTARTSYS;
1709 			break;
1710 		}
1711 		if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
1712 			error = -EFAULT;
1713 			break;
1714 		}
1715 
1716 		schedule();
1717 	}
1718 
1719 	current->state = TASK_RUNNING;
1720 	remove_wait_queue(&tfile->wq.wait, &wait);
1721 
1722 out:
1723 	*err = error;
1724 	return skb;
1725 }
1726 
1727 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
1728 			   struct iov_iter *to,
1729 			   int noblock, struct sk_buff *skb)
1730 {
1731 	ssize_t ret;
1732 	int err;
1733 
1734 	tun_debug(KERN_INFO, tun, "tun_do_read\n");
1735 
1736 	if (!iov_iter_count(to))
1737 		return 0;
1738 
1739 	if (!skb) {
1740 		/* Read frames from ring */
1741 		skb = tun_ring_recv(tfile, noblock, &err);
1742 		if (!skb)
1743 			return err;
1744 	}
1745 
1746 	ret = tun_put_user(tun, tfile, skb, to);
1747 	if (unlikely(ret < 0))
1748 		kfree_skb(skb);
1749 	else
1750 		consume_skb(skb);
1751 
1752 	return ret;
1753 }
1754 
1755 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
1756 {
1757 	struct file *file = iocb->ki_filp;
1758 	struct tun_file *tfile = file->private_data;
1759 	struct tun_struct *tun = __tun_get(tfile);
1760 	ssize_t len = iov_iter_count(to), ret;
1761 
1762 	if (!tun)
1763 		return -EBADFD;
1764 	ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK, NULL);
1765 	ret = min_t(ssize_t, ret, len);
1766 	if (ret > 0)
1767 		iocb->ki_pos = ret;
1768 	tun_put(tun);
1769 	return ret;
1770 }
1771 
1772 static void tun_free_netdev(struct net_device *dev)
1773 {
1774 	struct tun_struct *tun = netdev_priv(dev);
1775 
1776 	BUG_ON(!(list_empty(&tun->disabled)));
1777 	free_percpu(tun->pcpu_stats);
1778 	tun_flow_uninit(tun);
1779 	security_tun_dev_free_security(tun->security);
1780 }
1781 
1782 static void tun_setup(struct net_device *dev)
1783 {
1784 	struct tun_struct *tun = netdev_priv(dev);
1785 
1786 	tun->owner = INVALID_UID;
1787 	tun->group = INVALID_GID;
1788 
1789 	dev->ethtool_ops = &tun_ethtool_ops;
1790 	dev->needs_free_netdev = true;
1791 	dev->priv_destructor = tun_free_netdev;
1792 	/* We prefer our own queue length */
1793 	dev->tx_queue_len = TUN_READQ_SIZE;
1794 }
1795 
1796 /* Trivial set of netlink ops to allow deleting tun or tap
1797  * device with netlink.
1798  */
1799 static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
1800 			struct netlink_ext_ack *extack)
1801 {
1802 	return -EINVAL;
1803 }
1804 
1805 static struct rtnl_link_ops tun_link_ops __read_mostly = {
1806 	.kind		= DRV_NAME,
1807 	.priv_size	= sizeof(struct tun_struct),
1808 	.setup		= tun_setup,
1809 	.validate	= tun_validate,
1810 };
1811 
1812 static void tun_sock_write_space(struct sock *sk)
1813 {
1814 	struct tun_file *tfile;
1815 	wait_queue_head_t *wqueue;
1816 
1817 	if (!sock_writeable(sk))
1818 		return;
1819 
1820 	if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
1821 		return;
1822 
1823 	wqueue = sk_sleep(sk);
1824 	if (wqueue && waitqueue_active(wqueue))
1825 		wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1826 						POLLWRNORM | POLLWRBAND);
1827 
1828 	tfile = container_of(sk, struct tun_file, sk);
1829 	kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
1830 }
1831 
1832 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
1833 {
1834 	int ret;
1835 	struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1836 	struct tun_struct *tun = __tun_get(tfile);
1837 
1838 	if (!tun)
1839 		return -EBADFD;
1840 
1841 	ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter,
1842 			   m->msg_flags & MSG_DONTWAIT,
1843 			   m->msg_flags & MSG_MORE);
1844 	tun_put(tun);
1845 	return ret;
1846 }
1847 
1848 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
1849 		       int flags)
1850 {
1851 	struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1852 	struct tun_struct *tun = __tun_get(tfile);
1853 	int ret;
1854 
1855 	if (!tun)
1856 		return -EBADFD;
1857 
1858 	if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
1859 		ret = -EINVAL;
1860 		goto out;
1861 	}
1862 	if (flags & MSG_ERRQUEUE) {
1863 		ret = sock_recv_errqueue(sock->sk, m, total_len,
1864 					 SOL_PACKET, TUN_TX_TIMESTAMP);
1865 		goto out;
1866 	}
1867 	ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT,
1868 			  m->msg_control);
1869 	if (ret > (ssize_t)total_len) {
1870 		m->msg_flags |= MSG_TRUNC;
1871 		ret = flags & MSG_TRUNC ? ret : total_len;
1872 	}
1873 out:
1874 	tun_put(tun);
1875 	return ret;
1876 }
1877 
1878 static int tun_peek_len(struct socket *sock)
1879 {
1880 	struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1881 	struct tun_struct *tun;
1882 	int ret = 0;
1883 
1884 	tun = __tun_get(tfile);
1885 	if (!tun)
1886 		return 0;
1887 
1888 	ret = skb_array_peek_len(&tfile->tx_array);
1889 	tun_put(tun);
1890 
1891 	return ret;
1892 }
1893 
1894 /* Ops structure to mimic raw sockets with tun */
1895 static const struct proto_ops tun_socket_ops = {
1896 	.peek_len = tun_peek_len,
1897 	.sendmsg = tun_sendmsg,
1898 	.recvmsg = tun_recvmsg,
1899 };
1900 
1901 static struct proto tun_proto = {
1902 	.name		= "tun",
1903 	.owner		= THIS_MODULE,
1904 	.obj_size	= sizeof(struct tun_file),
1905 };
1906 
1907 static int tun_flags(struct tun_struct *tun)
1908 {
1909 	return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
1910 }
1911 
1912 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1913 			      char *buf)
1914 {
1915 	struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1916 	return sprintf(buf, "0x%x\n", tun_flags(tun));
1917 }
1918 
1919 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1920 			      char *buf)
1921 {
1922 	struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1923 	return uid_valid(tun->owner)?
1924 		sprintf(buf, "%u\n",
1925 			from_kuid_munged(current_user_ns(), tun->owner)):
1926 		sprintf(buf, "-1\n");
1927 }
1928 
1929 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1930 			      char *buf)
1931 {
1932 	struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1933 	return gid_valid(tun->group) ?
1934 		sprintf(buf, "%u\n",
1935 			from_kgid_munged(current_user_ns(), tun->group)):
1936 		sprintf(buf, "-1\n");
1937 }
1938 
1939 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1940 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1941 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1942 
1943 static struct attribute *tun_dev_attrs[] = {
1944 	&dev_attr_tun_flags.attr,
1945 	&dev_attr_owner.attr,
1946 	&dev_attr_group.attr,
1947 	NULL
1948 };
1949 
1950 static const struct attribute_group tun_attr_group = {
1951 	.attrs = tun_dev_attrs
1952 };
1953 
1954 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1955 {
1956 	struct tun_struct *tun;
1957 	struct tun_file *tfile = file->private_data;
1958 	struct net_device *dev;
1959 	int err;
1960 
1961 	if (tfile->detached)
1962 		return -EINVAL;
1963 
1964 	dev = __dev_get_by_name(net, ifr->ifr_name);
1965 	if (dev) {
1966 		if (ifr->ifr_flags & IFF_TUN_EXCL)
1967 			return -EBUSY;
1968 		if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1969 			tun = netdev_priv(dev);
1970 		else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1971 			tun = netdev_priv(dev);
1972 		else
1973 			return -EINVAL;
1974 
1975 		if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
1976 		    !!(tun->flags & IFF_MULTI_QUEUE))
1977 			return -EINVAL;
1978 
1979 		if (tun_not_capable(tun))
1980 			return -EPERM;
1981 		err = security_tun_dev_open(tun->security);
1982 		if (err < 0)
1983 			return err;
1984 
1985 		err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER);
1986 		if (err < 0)
1987 			return err;
1988 
1989 		if (tun->flags & IFF_MULTI_QUEUE &&
1990 		    (tun->numqueues + tun->numdisabled > 1)) {
1991 			/* One or more queue has already been attached, no need
1992 			 * to initialize the device again.
1993 			 */
1994 			return 0;
1995 		}
1996 	}
1997 	else {
1998 		char *name;
1999 		unsigned long flags = 0;
2000 		int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
2001 			     MAX_TAP_QUEUES : 1;
2002 
2003 		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2004 			return -EPERM;
2005 		err = security_tun_dev_create();
2006 		if (err < 0)
2007 			return err;
2008 
2009 		/* Set dev type */
2010 		if (ifr->ifr_flags & IFF_TUN) {
2011 			/* TUN device */
2012 			flags |= IFF_TUN;
2013 			name = "tun%d";
2014 		} else if (ifr->ifr_flags & IFF_TAP) {
2015 			/* TAP device */
2016 			flags |= IFF_TAP;
2017 			name = "tap%d";
2018 		} else
2019 			return -EINVAL;
2020 
2021 		if (*ifr->ifr_name)
2022 			name = ifr->ifr_name;
2023 
2024 		dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
2025 				       NET_NAME_UNKNOWN, tun_setup, queues,
2026 				       queues);
2027 
2028 		if (!dev)
2029 			return -ENOMEM;
2030 		err = dev_get_valid_name(net, dev, name);
2031 		if (err)
2032 			goto err_free_dev;
2033 
2034 		dev_net_set(dev, net);
2035 		dev->rtnl_link_ops = &tun_link_ops;
2036 		dev->ifindex = tfile->ifindex;
2037 		dev->sysfs_groups[0] = &tun_attr_group;
2038 
2039 		tun = netdev_priv(dev);
2040 		tun->dev = dev;
2041 		tun->flags = flags;
2042 		tun->txflt.count = 0;
2043 		tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
2044 
2045 		tun->align = NET_SKB_PAD;
2046 		tun->filter_attached = false;
2047 		tun->sndbuf = tfile->socket.sk->sk_sndbuf;
2048 		tun->rx_batched = 0;
2049 
2050 		tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats);
2051 		if (!tun->pcpu_stats) {
2052 			err = -ENOMEM;
2053 			goto err_free_dev;
2054 		}
2055 
2056 		spin_lock_init(&tun->lock);
2057 
2058 		err = security_tun_dev_alloc_security(&tun->security);
2059 		if (err < 0)
2060 			goto err_free_stat;
2061 
2062 		tun_net_init(dev);
2063 		tun_flow_init(tun);
2064 
2065 		dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
2066 				   TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
2067 				   NETIF_F_HW_VLAN_STAG_TX;
2068 		dev->features = dev->hw_features | NETIF_F_LLTX;
2069 		dev->vlan_features = dev->features &
2070 				     ~(NETIF_F_HW_VLAN_CTAG_TX |
2071 				       NETIF_F_HW_VLAN_STAG_TX);
2072 
2073 		INIT_LIST_HEAD(&tun->disabled);
2074 		err = tun_attach(tun, file, false);
2075 		if (err < 0)
2076 			goto err_free_flow;
2077 
2078 		err = register_netdevice(tun->dev);
2079 		if (err < 0)
2080 			goto err_detach;
2081 	}
2082 
2083 	netif_carrier_on(tun->dev);
2084 
2085 	tun_debug(KERN_INFO, tun, "tun_set_iff\n");
2086 
2087 	tun->flags = (tun->flags & ~TUN_FEATURES) |
2088 		(ifr->ifr_flags & TUN_FEATURES);
2089 
2090 	/* Make sure persistent devices do not get stuck in
2091 	 * xoff state.
2092 	 */
2093 	if (netif_running(tun->dev))
2094 		netif_tx_wake_all_queues(tun->dev);
2095 
2096 	strcpy(ifr->ifr_name, tun->dev->name);
2097 	return 0;
2098 
2099 err_detach:
2100 	tun_detach_all(dev);
2101 	/* register_netdevice() already called tun_free_netdev() */
2102 	goto err_free_dev;
2103 
2104 err_free_flow:
2105 	tun_flow_uninit(tun);
2106 	security_tun_dev_free_security(tun->security);
2107 err_free_stat:
2108 	free_percpu(tun->pcpu_stats);
2109 err_free_dev:
2110 	free_netdev(dev);
2111 	return err;
2112 }
2113 
2114 static void tun_get_iff(struct net *net, struct tun_struct *tun,
2115 		       struct ifreq *ifr)
2116 {
2117 	tun_debug(KERN_INFO, tun, "tun_get_iff\n");
2118 
2119 	strcpy(ifr->ifr_name, tun->dev->name);
2120 
2121 	ifr->ifr_flags = tun_flags(tun);
2122 
2123 }
2124 
2125 /* This is like a cut-down ethtool ops, except done via tun fd so no
2126  * privs required. */
2127 static int set_offload(struct tun_struct *tun, unsigned long arg)
2128 {
2129 	netdev_features_t features = 0;
2130 
2131 	if (arg & TUN_F_CSUM) {
2132 		features |= NETIF_F_HW_CSUM;
2133 		arg &= ~TUN_F_CSUM;
2134 
2135 		if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
2136 			if (arg & TUN_F_TSO_ECN) {
2137 				features |= NETIF_F_TSO_ECN;
2138 				arg &= ~TUN_F_TSO_ECN;
2139 			}
2140 			if (arg & TUN_F_TSO4)
2141 				features |= NETIF_F_TSO;
2142 			if (arg & TUN_F_TSO6)
2143 				features |= NETIF_F_TSO6;
2144 			arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
2145 		}
2146 	}
2147 
2148 	/* This gives the user a way to test for new features in future by
2149 	 * trying to set them. */
2150 	if (arg)
2151 		return -EINVAL;
2152 
2153 	tun->set_features = features;
2154 	tun->dev->wanted_features &= ~TUN_USER_FEATURES;
2155 	tun->dev->wanted_features |= features;
2156 	netdev_update_features(tun->dev);
2157 
2158 	return 0;
2159 }
2160 
2161 static void tun_detach_filter(struct tun_struct *tun, int n)
2162 {
2163 	int i;
2164 	struct tun_file *tfile;
2165 
2166 	for (i = 0; i < n; i++) {
2167 		tfile = rtnl_dereference(tun->tfiles[i]);
2168 		lock_sock(tfile->socket.sk);
2169 		sk_detach_filter(tfile->socket.sk);
2170 		release_sock(tfile->socket.sk);
2171 	}
2172 
2173 	tun->filter_attached = false;
2174 }
2175 
2176 static int tun_attach_filter(struct tun_struct *tun)
2177 {
2178 	int i, ret = 0;
2179 	struct tun_file *tfile;
2180 
2181 	for (i = 0; i < tun->numqueues; i++) {
2182 		tfile = rtnl_dereference(tun->tfiles[i]);
2183 		lock_sock(tfile->socket.sk);
2184 		ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
2185 		release_sock(tfile->socket.sk);
2186 		if (ret) {
2187 			tun_detach_filter(tun, i);
2188 			return ret;
2189 		}
2190 	}
2191 
2192 	tun->filter_attached = true;
2193 	return ret;
2194 }
2195 
2196 static void tun_set_sndbuf(struct tun_struct *tun)
2197 {
2198 	struct tun_file *tfile;
2199 	int i;
2200 
2201 	for (i = 0; i < tun->numqueues; i++) {
2202 		tfile = rtnl_dereference(tun->tfiles[i]);
2203 		tfile->socket.sk->sk_sndbuf = tun->sndbuf;
2204 	}
2205 }
2206 
2207 static int tun_set_queue(struct file *file, struct ifreq *ifr)
2208 {
2209 	struct tun_file *tfile = file->private_data;
2210 	struct tun_struct *tun;
2211 	int ret = 0;
2212 
2213 	rtnl_lock();
2214 
2215 	if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
2216 		tun = tfile->detached;
2217 		if (!tun) {
2218 			ret = -EINVAL;
2219 			goto unlock;
2220 		}
2221 		ret = security_tun_dev_attach_queue(tun->security);
2222 		if (ret < 0)
2223 			goto unlock;
2224 		ret = tun_attach(tun, file, false);
2225 	} else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
2226 		tun = rtnl_dereference(tfile->tun);
2227 		if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
2228 			ret = -EINVAL;
2229 		else
2230 			__tun_detach(tfile, false);
2231 	} else
2232 		ret = -EINVAL;
2233 
2234 unlock:
2235 	rtnl_unlock();
2236 	return ret;
2237 }
2238 
2239 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
2240 			    unsigned long arg, int ifreq_len)
2241 {
2242 	struct tun_file *tfile = file->private_data;
2243 	struct tun_struct *tun;
2244 	void __user* argp = (void __user*)arg;
2245 	struct ifreq ifr;
2246 	kuid_t owner;
2247 	kgid_t group;
2248 	int sndbuf;
2249 	int vnet_hdr_sz;
2250 	unsigned int ifindex;
2251 	int le;
2252 	int ret;
2253 
2254 	if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == SOCK_IOC_TYPE) {
2255 		if (copy_from_user(&ifr, argp, ifreq_len))
2256 			return -EFAULT;
2257 	} else {
2258 		memset(&ifr, 0, sizeof(ifr));
2259 	}
2260 	if (cmd == TUNGETFEATURES) {
2261 		/* Currently this just means: "what IFF flags are valid?".
2262 		 * This is needed because we never checked for invalid flags on
2263 		 * TUNSETIFF.
2264 		 */
2265 		return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
2266 				(unsigned int __user*)argp);
2267 	} else if (cmd == TUNSETQUEUE)
2268 		return tun_set_queue(file, &ifr);
2269 
2270 	ret = 0;
2271 	rtnl_lock();
2272 
2273 	tun = __tun_get(tfile);
2274 	if (cmd == TUNSETIFF) {
2275 		ret = -EEXIST;
2276 		if (tun)
2277 			goto unlock;
2278 
2279 		ifr.ifr_name[IFNAMSIZ-1] = '\0';
2280 
2281 		ret = tun_set_iff(sock_net(&tfile->sk), file, &ifr);
2282 
2283 		if (ret)
2284 			goto unlock;
2285 
2286 		if (copy_to_user(argp, &ifr, ifreq_len))
2287 			ret = -EFAULT;
2288 		goto unlock;
2289 	}
2290 	if (cmd == TUNSETIFINDEX) {
2291 		ret = -EPERM;
2292 		if (tun)
2293 			goto unlock;
2294 
2295 		ret = -EFAULT;
2296 		if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
2297 			goto unlock;
2298 
2299 		ret = 0;
2300 		tfile->ifindex = ifindex;
2301 		goto unlock;
2302 	}
2303 
2304 	ret = -EBADFD;
2305 	if (!tun)
2306 		goto unlock;
2307 
2308 	tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
2309 
2310 	ret = 0;
2311 	switch (cmd) {
2312 	case TUNGETIFF:
2313 		tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2314 
2315 		if (tfile->detached)
2316 			ifr.ifr_flags |= IFF_DETACH_QUEUE;
2317 		if (!tfile->socket.sk->sk_filter)
2318 			ifr.ifr_flags |= IFF_NOFILTER;
2319 
2320 		if (copy_to_user(argp, &ifr, ifreq_len))
2321 			ret = -EFAULT;
2322 		break;
2323 
2324 	case TUNSETNOCSUM:
2325 		/* Disable/Enable checksum */
2326 
2327 		/* [unimplemented] */
2328 		tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
2329 			  arg ? "disabled" : "enabled");
2330 		break;
2331 
2332 	case TUNSETPERSIST:
2333 		/* Disable/Enable persist mode. Keep an extra reference to the
2334 		 * module to prevent the module being unprobed.
2335 		 */
2336 		if (arg && !(tun->flags & IFF_PERSIST)) {
2337 			tun->flags |= IFF_PERSIST;
2338 			__module_get(THIS_MODULE);
2339 		}
2340 		if (!arg && (tun->flags & IFF_PERSIST)) {
2341 			tun->flags &= ~IFF_PERSIST;
2342 			module_put(THIS_MODULE);
2343 		}
2344 
2345 		tun_debug(KERN_INFO, tun, "persist %s\n",
2346 			  arg ? "enabled" : "disabled");
2347 		break;
2348 
2349 	case TUNSETOWNER:
2350 		/* Set owner of the device */
2351 		owner = make_kuid(current_user_ns(), arg);
2352 		if (!uid_valid(owner)) {
2353 			ret = -EINVAL;
2354 			break;
2355 		}
2356 		tun->owner = owner;
2357 		tun_debug(KERN_INFO, tun, "owner set to %u\n",
2358 			  from_kuid(&init_user_ns, tun->owner));
2359 		break;
2360 
2361 	case TUNSETGROUP:
2362 		/* Set group of the device */
2363 		group = make_kgid(current_user_ns(), arg);
2364 		if (!gid_valid(group)) {
2365 			ret = -EINVAL;
2366 			break;
2367 		}
2368 		tun->group = group;
2369 		tun_debug(KERN_INFO, tun, "group set to %u\n",
2370 			  from_kgid(&init_user_ns, tun->group));
2371 		break;
2372 
2373 	case TUNSETLINK:
2374 		/* Only allow setting the type when the interface is down */
2375 		if (tun->dev->flags & IFF_UP) {
2376 			tun_debug(KERN_INFO, tun,
2377 				  "Linktype set failed because interface is up\n");
2378 			ret = -EBUSY;
2379 		} else {
2380 			tun->dev->type = (int) arg;
2381 			tun_debug(KERN_INFO, tun, "linktype set to %d\n",
2382 				  tun->dev->type);
2383 			ret = 0;
2384 		}
2385 		break;
2386 
2387 #ifdef TUN_DEBUG
2388 	case TUNSETDEBUG:
2389 		tun->debug = arg;
2390 		break;
2391 #endif
2392 	case TUNSETOFFLOAD:
2393 		ret = set_offload(tun, arg);
2394 		break;
2395 
2396 	case TUNSETTXFILTER:
2397 		/* Can be set only for TAPs */
2398 		ret = -EINVAL;
2399 		if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2400 			break;
2401 		ret = update_filter(&tun->txflt, (void __user *)arg);
2402 		break;
2403 
2404 	case SIOCGIFHWADDR:
2405 		/* Get hw address */
2406 		memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
2407 		ifr.ifr_hwaddr.sa_family = tun->dev->type;
2408 		if (copy_to_user(argp, &ifr, ifreq_len))
2409 			ret = -EFAULT;
2410 		break;
2411 
2412 	case SIOCSIFHWADDR:
2413 		/* Set hw address */
2414 		tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
2415 			  ifr.ifr_hwaddr.sa_data);
2416 
2417 		ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
2418 		break;
2419 
2420 	case TUNGETSNDBUF:
2421 		sndbuf = tfile->socket.sk->sk_sndbuf;
2422 		if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
2423 			ret = -EFAULT;
2424 		break;
2425 
2426 	case TUNSETSNDBUF:
2427 		if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
2428 			ret = -EFAULT;
2429 			break;
2430 		}
2431 
2432 		tun->sndbuf = sndbuf;
2433 		tun_set_sndbuf(tun);
2434 		break;
2435 
2436 	case TUNGETVNETHDRSZ:
2437 		vnet_hdr_sz = tun->vnet_hdr_sz;
2438 		if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
2439 			ret = -EFAULT;
2440 		break;
2441 
2442 	case TUNSETVNETHDRSZ:
2443 		if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
2444 			ret = -EFAULT;
2445 			break;
2446 		}
2447 		if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
2448 			ret = -EINVAL;
2449 			break;
2450 		}
2451 
2452 		tun->vnet_hdr_sz = vnet_hdr_sz;
2453 		break;
2454 
2455 	case TUNGETVNETLE:
2456 		le = !!(tun->flags & TUN_VNET_LE);
2457 		if (put_user(le, (int __user *)argp))
2458 			ret = -EFAULT;
2459 		break;
2460 
2461 	case TUNSETVNETLE:
2462 		if (get_user(le, (int __user *)argp)) {
2463 			ret = -EFAULT;
2464 			break;
2465 		}
2466 		if (le)
2467 			tun->flags |= TUN_VNET_LE;
2468 		else
2469 			tun->flags &= ~TUN_VNET_LE;
2470 		break;
2471 
2472 	case TUNGETVNETBE:
2473 		ret = tun_get_vnet_be(tun, argp);
2474 		break;
2475 
2476 	case TUNSETVNETBE:
2477 		ret = tun_set_vnet_be(tun, argp);
2478 		break;
2479 
2480 	case TUNATTACHFILTER:
2481 		/* Can be set only for TAPs */
2482 		ret = -EINVAL;
2483 		if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2484 			break;
2485 		ret = -EFAULT;
2486 		if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
2487 			break;
2488 
2489 		ret = tun_attach_filter(tun);
2490 		break;
2491 
2492 	case TUNDETACHFILTER:
2493 		/* Can be set only for TAPs */
2494 		ret = -EINVAL;
2495 		if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2496 			break;
2497 		ret = 0;
2498 		tun_detach_filter(tun, tun->numqueues);
2499 		break;
2500 
2501 	case TUNGETFILTER:
2502 		ret = -EINVAL;
2503 		if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2504 			break;
2505 		ret = -EFAULT;
2506 		if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
2507 			break;
2508 		ret = 0;
2509 		break;
2510 
2511 	default:
2512 		ret = -EINVAL;
2513 		break;
2514 	}
2515 
2516 unlock:
2517 	rtnl_unlock();
2518 	if (tun)
2519 		tun_put(tun);
2520 	return ret;
2521 }
2522 
2523 static long tun_chr_ioctl(struct file *file,
2524 			  unsigned int cmd, unsigned long arg)
2525 {
2526 	return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
2527 }
2528 
2529 #ifdef CONFIG_COMPAT
2530 static long tun_chr_compat_ioctl(struct file *file,
2531 			 unsigned int cmd, unsigned long arg)
2532 {
2533 	switch (cmd) {
2534 	case TUNSETIFF:
2535 	case TUNGETIFF:
2536 	case TUNSETTXFILTER:
2537 	case TUNGETSNDBUF:
2538 	case TUNSETSNDBUF:
2539 	case SIOCGIFHWADDR:
2540 	case SIOCSIFHWADDR:
2541 		arg = (unsigned long)compat_ptr(arg);
2542 		break;
2543 	default:
2544 		arg = (compat_ulong_t)arg;
2545 		break;
2546 	}
2547 
2548 	/*
2549 	 * compat_ifreq is shorter than ifreq, so we must not access beyond
2550 	 * the end of that structure. All fields that are used in this
2551 	 * driver are compatible though, we don't need to convert the
2552 	 * contents.
2553 	 */
2554 	return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
2555 }
2556 #endif /* CONFIG_COMPAT */
2557 
2558 static int tun_chr_fasync(int fd, struct file *file, int on)
2559 {
2560 	struct tun_file *tfile = file->private_data;
2561 	int ret;
2562 
2563 	if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
2564 		goto out;
2565 
2566 	if (on) {
2567 		__f_setown(file, task_pid(current), PIDTYPE_PID, 0);
2568 		tfile->flags |= TUN_FASYNC;
2569 	} else
2570 		tfile->flags &= ~TUN_FASYNC;
2571 	ret = 0;
2572 out:
2573 	return ret;
2574 }
2575 
2576 static int tun_chr_open(struct inode *inode, struct file * file)
2577 {
2578 	struct net *net = current->nsproxy->net_ns;
2579 	struct tun_file *tfile;
2580 
2581 	DBG1(KERN_INFO, "tunX: tun_chr_open\n");
2582 
2583 	tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
2584 					    &tun_proto, 0);
2585 	if (!tfile)
2586 		return -ENOMEM;
2587 	RCU_INIT_POINTER(tfile->tun, NULL);
2588 	tfile->flags = 0;
2589 	tfile->ifindex = 0;
2590 
2591 	init_waitqueue_head(&tfile->wq.wait);
2592 	RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq);
2593 
2594 	tfile->socket.file = file;
2595 	tfile->socket.ops = &tun_socket_ops;
2596 
2597 	sock_init_data(&tfile->socket, &tfile->sk);
2598 
2599 	tfile->sk.sk_write_space = tun_sock_write_space;
2600 	tfile->sk.sk_sndbuf = INT_MAX;
2601 
2602 	file->private_data = tfile;
2603 	INIT_LIST_HEAD(&tfile->next);
2604 
2605 	sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
2606 
2607 	return 0;
2608 }
2609 
2610 static int tun_chr_close(struct inode *inode, struct file *file)
2611 {
2612 	struct tun_file *tfile = file->private_data;
2613 
2614 	tun_detach(tfile, true);
2615 
2616 	return 0;
2617 }
2618 
2619 #ifdef CONFIG_PROC_FS
2620 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *f)
2621 {
2622 	struct tun_struct *tun;
2623 	struct ifreq ifr;
2624 
2625 	memset(&ifr, 0, sizeof(ifr));
2626 
2627 	rtnl_lock();
2628 	tun = tun_get(f);
2629 	if (tun)
2630 		tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2631 	rtnl_unlock();
2632 
2633 	if (tun)
2634 		tun_put(tun);
2635 
2636 	seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
2637 }
2638 #endif
2639 
2640 static const struct file_operations tun_fops = {
2641 	.owner	= THIS_MODULE,
2642 	.llseek = no_llseek,
2643 	.read_iter  = tun_chr_read_iter,
2644 	.write_iter = tun_chr_write_iter,
2645 	.poll	= tun_chr_poll,
2646 	.unlocked_ioctl	= tun_chr_ioctl,
2647 #ifdef CONFIG_COMPAT
2648 	.compat_ioctl = tun_chr_compat_ioctl,
2649 #endif
2650 	.open	= tun_chr_open,
2651 	.release = tun_chr_close,
2652 	.fasync = tun_chr_fasync,
2653 #ifdef CONFIG_PROC_FS
2654 	.show_fdinfo = tun_chr_show_fdinfo,
2655 #endif
2656 };
2657 
2658 static struct miscdevice tun_miscdev = {
2659 	.minor = TUN_MINOR,
2660 	.name = "tun",
2661 	.nodename = "net/tun",
2662 	.fops = &tun_fops,
2663 };
2664 
2665 /* ethtool interface */
2666 
2667 static int tun_get_link_ksettings(struct net_device *dev,
2668 				  struct ethtool_link_ksettings *cmd)
2669 {
2670 	ethtool_link_ksettings_zero_link_mode(cmd, supported);
2671 	ethtool_link_ksettings_zero_link_mode(cmd, advertising);
2672 	cmd->base.speed		= SPEED_10;
2673 	cmd->base.duplex	= DUPLEX_FULL;
2674 	cmd->base.port		= PORT_TP;
2675 	cmd->base.phy_address	= 0;
2676 	cmd->base.autoneg	= AUTONEG_DISABLE;
2677 	return 0;
2678 }
2679 
2680 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
2681 {
2682 	struct tun_struct *tun = netdev_priv(dev);
2683 
2684 	strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
2685 	strlcpy(info->version, DRV_VERSION, sizeof(info->version));
2686 
2687 	switch (tun->flags & TUN_TYPE_MASK) {
2688 	case IFF_TUN:
2689 		strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
2690 		break;
2691 	case IFF_TAP:
2692 		strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
2693 		break;
2694 	}
2695 }
2696 
2697 static u32 tun_get_msglevel(struct net_device *dev)
2698 {
2699 #ifdef TUN_DEBUG
2700 	struct tun_struct *tun = netdev_priv(dev);
2701 	return tun->debug;
2702 #else
2703 	return -EOPNOTSUPP;
2704 #endif
2705 }
2706 
2707 static void tun_set_msglevel(struct net_device *dev, u32 value)
2708 {
2709 #ifdef TUN_DEBUG
2710 	struct tun_struct *tun = netdev_priv(dev);
2711 	tun->debug = value;
2712 #endif
2713 }
2714 
2715 static int tun_get_coalesce(struct net_device *dev,
2716 			    struct ethtool_coalesce *ec)
2717 {
2718 	struct tun_struct *tun = netdev_priv(dev);
2719 
2720 	ec->rx_max_coalesced_frames = tun->rx_batched;
2721 
2722 	return 0;
2723 }
2724 
2725 static int tun_set_coalesce(struct net_device *dev,
2726 			    struct ethtool_coalesce *ec)
2727 {
2728 	struct tun_struct *tun = netdev_priv(dev);
2729 
2730 	if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT)
2731 		tun->rx_batched = NAPI_POLL_WEIGHT;
2732 	else
2733 		tun->rx_batched = ec->rx_max_coalesced_frames;
2734 
2735 	return 0;
2736 }
2737 
2738 static const struct ethtool_ops tun_ethtool_ops = {
2739 	.get_drvinfo	= tun_get_drvinfo,
2740 	.get_msglevel	= tun_get_msglevel,
2741 	.set_msglevel	= tun_set_msglevel,
2742 	.get_link	= ethtool_op_get_link,
2743 	.get_ts_info	= ethtool_op_get_ts_info,
2744 	.get_coalesce   = tun_get_coalesce,
2745 	.set_coalesce   = tun_set_coalesce,
2746 	.get_link_ksettings = tun_get_link_ksettings,
2747 };
2748 
2749 static int tun_queue_resize(struct tun_struct *tun)
2750 {
2751 	struct net_device *dev = tun->dev;
2752 	struct tun_file *tfile;
2753 	struct skb_array **arrays;
2754 	int n = tun->numqueues + tun->numdisabled;
2755 	int ret, i;
2756 
2757 	arrays = kmalloc_array(n, sizeof(*arrays), GFP_KERNEL);
2758 	if (!arrays)
2759 		return -ENOMEM;
2760 
2761 	for (i = 0; i < tun->numqueues; i++) {
2762 		tfile = rtnl_dereference(tun->tfiles[i]);
2763 		arrays[i] = &tfile->tx_array;
2764 	}
2765 	list_for_each_entry(tfile, &tun->disabled, next)
2766 		arrays[i++] = &tfile->tx_array;
2767 
2768 	ret = skb_array_resize_multiple(arrays, n,
2769 					dev->tx_queue_len, GFP_KERNEL);
2770 
2771 	kfree(arrays);
2772 	return ret;
2773 }
2774 
2775 static int tun_device_event(struct notifier_block *unused,
2776 			    unsigned long event, void *ptr)
2777 {
2778 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
2779 	struct tun_struct *tun = netdev_priv(dev);
2780 
2781 	if (dev->rtnl_link_ops != &tun_link_ops)
2782 		return NOTIFY_DONE;
2783 
2784 	switch (event) {
2785 	case NETDEV_CHANGE_TX_QUEUE_LEN:
2786 		if (tun_queue_resize(tun))
2787 			return NOTIFY_BAD;
2788 		break;
2789 	default:
2790 		break;
2791 	}
2792 
2793 	return NOTIFY_DONE;
2794 }
2795 
2796 static struct notifier_block tun_notifier_block __read_mostly = {
2797 	.notifier_call	= tun_device_event,
2798 };
2799 
2800 static int __init tun_init(void)
2801 {
2802 	int ret = 0;
2803 
2804 	pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
2805 
2806 	ret = rtnl_link_register(&tun_link_ops);
2807 	if (ret) {
2808 		pr_err("Can't register link_ops\n");
2809 		goto err_linkops;
2810 	}
2811 
2812 	ret = misc_register(&tun_miscdev);
2813 	if (ret) {
2814 		pr_err("Can't register misc device %d\n", TUN_MINOR);
2815 		goto err_misc;
2816 	}
2817 
2818 	ret = register_netdevice_notifier(&tun_notifier_block);
2819 	if (ret) {
2820 		pr_err("Can't register netdevice notifier\n");
2821 		goto err_notifier;
2822 	}
2823 
2824 	return  0;
2825 
2826 err_notifier:
2827 	misc_deregister(&tun_miscdev);
2828 err_misc:
2829 	rtnl_link_unregister(&tun_link_ops);
2830 err_linkops:
2831 	return ret;
2832 }
2833 
2834 static void tun_cleanup(void)
2835 {
2836 	misc_deregister(&tun_miscdev);
2837 	rtnl_link_unregister(&tun_link_ops);
2838 	unregister_netdevice_notifier(&tun_notifier_block);
2839 }
2840 
2841 /* Get an underlying socket object from tun file.  Returns error unless file is
2842  * attached to a device.  The returned object works like a packet socket, it
2843  * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
2844  * holding a reference to the file for as long as the socket is in use. */
2845 struct socket *tun_get_socket(struct file *file)
2846 {
2847 	struct tun_file *tfile;
2848 	if (file->f_op != &tun_fops)
2849 		return ERR_PTR(-EINVAL);
2850 	tfile = file->private_data;
2851 	if (!tfile)
2852 		return ERR_PTR(-EBADFD);
2853 	return &tfile->socket;
2854 }
2855 EXPORT_SYMBOL_GPL(tun_get_socket);
2856 
2857 struct skb_array *tun_get_skb_array(struct file *file)
2858 {
2859 	struct tun_file *tfile;
2860 
2861 	if (file->f_op != &tun_fops)
2862 		return ERR_PTR(-EINVAL);
2863 	tfile = file->private_data;
2864 	if (!tfile)
2865 		return ERR_PTR(-EBADFD);
2866 	return &tfile->tx_array;
2867 }
2868 EXPORT_SYMBOL_GPL(tun_get_skb_array);
2869 
2870 module_init(tun_init);
2871 module_exit(tun_cleanup);
2872 MODULE_DESCRIPTION(DRV_DESCRIPTION);
2873 MODULE_AUTHOR(DRV_COPYRIGHT);
2874 MODULE_LICENSE("GPL");
2875 MODULE_ALIAS_MISCDEV(TUN_MINOR);
2876 MODULE_ALIAS("devname:net/tun");
2877