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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 struct mutex napi_mutex; /* Protects access to the above napi */
179 struct list_head next;
180 struct tun_struct *detached;
181 struct skb_array tx_array;
182 };
183
184 struct tun_flow_entry {
185 struct hlist_node hash_link;
186 struct rcu_head rcu;
187 struct tun_struct *tun;
188
189 u32 rxhash;
190 u32 rps_rxhash;
191 int queue_index;
192 unsigned long updated;
193 };
194
195 #define TUN_NUM_FLOW_ENTRIES 1024
196
197 /* Since the socket were moved to tun_file, to preserve the behavior of persist
198 * device, socket filter, sndbuf and vnet header size were restore when the
199 * file were attached to a persist device.
200 */
201 struct tun_struct {
202 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES];
203 unsigned int numqueues;
204 unsigned int flags;
205 kuid_t owner;
206 kgid_t group;
207
208 struct net_device *dev;
209 netdev_features_t set_features;
210 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
211 NETIF_F_TSO6)
212
213 int align;
214 int vnet_hdr_sz;
215 int sndbuf;
216 struct tap_filter txflt;
217 struct sock_fprog fprog;
218 /* protected by rtnl lock */
219 bool filter_attached;
220 #ifdef TUN_DEBUG
221 int debug;
222 #endif
223 spinlock_t lock;
224 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
225 struct timer_list flow_gc_timer;
226 unsigned long ageing_time;
227 unsigned int numdisabled;
228 struct list_head disabled;
229 void *security;
230 u32 flow_count;
231 u32 rx_batched;
232 struct tun_pcpu_stats __percpu *pcpu_stats;
233 struct bpf_prog __rcu *xdp_prog;
234 };
235
236 static int tun_napi_receive(struct napi_struct *napi, int budget)
237 {
238 struct tun_file *tfile = container_of(napi, struct tun_file, napi);
239 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
240 struct sk_buff_head process_queue;
241 struct sk_buff *skb;
242 int received = 0;
243
244 __skb_queue_head_init(&process_queue);
245
246 spin_lock(&queue->lock);
247 skb_queue_splice_tail_init(queue, &process_queue);
248 spin_unlock(&queue->lock);
249
250 while (received < budget && (skb = __skb_dequeue(&process_queue))) {
251 napi_gro_receive(napi, skb);
252 ++received;
253 }
254
255 if (!skb_queue_empty(&process_queue)) {
256 spin_lock(&queue->lock);
257 skb_queue_splice(&process_queue, queue);
258 spin_unlock(&queue->lock);
259 }
260
261 return received;
262 }
263
264 static int tun_napi_poll(struct napi_struct *napi, int budget)
265 {
266 unsigned int received;
267
268 received = tun_napi_receive(napi, budget);
269
270 if (received < budget)
271 napi_complete_done(napi, received);
272
273 return received;
274 }
275
276 static void tun_napi_init(struct tun_struct *tun, struct tun_file *tfile,
277 bool napi_en)
278 {
279 if (napi_en) {
280 netif_napi_add(tun->dev, &tfile->napi, tun_napi_poll,
281 NAPI_POLL_WEIGHT);
282 napi_enable(&tfile->napi);
283 mutex_init(&tfile->napi_mutex);
284 }
285 }
286
287 static void tun_napi_disable(struct tun_struct *tun, struct tun_file *tfile)
288 {
289 if (tun->flags & IFF_NAPI)
290 napi_disable(&tfile->napi);
291 }
292
293 static void tun_napi_del(struct tun_struct *tun, struct tun_file *tfile)
294 {
295 if (tun->flags & IFF_NAPI)
296 netif_napi_del(&tfile->napi);
297 }
298
299 static bool tun_napi_frags_enabled(const struct tun_struct *tun)
300 {
301 return READ_ONCE(tun->flags) & IFF_NAPI_FRAGS;
302 }
303
304 #ifdef CONFIG_TUN_VNET_CROSS_LE
305 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
306 {
307 return tun->flags & TUN_VNET_BE ? false :
308 virtio_legacy_is_little_endian();
309 }
310
311 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
312 {
313 int be = !!(tun->flags & TUN_VNET_BE);
314
315 if (put_user(be, argp))
316 return -EFAULT;
317
318 return 0;
319 }
320
321 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
322 {
323 int be;
324
325 if (get_user(be, argp))
326 return -EFAULT;
327
328 if (be)
329 tun->flags |= TUN_VNET_BE;
330 else
331 tun->flags &= ~TUN_VNET_BE;
332
333 return 0;
334 }
335 #else
336 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
337 {
338 return virtio_legacy_is_little_endian();
339 }
340
341 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
342 {
343 return -EINVAL;
344 }
345
346 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
347 {
348 return -EINVAL;
349 }
350 #endif /* CONFIG_TUN_VNET_CROSS_LE */
351
352 static inline bool tun_is_little_endian(struct tun_struct *tun)
353 {
354 return tun->flags & TUN_VNET_LE ||
355 tun_legacy_is_little_endian(tun);
356 }
357
358 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
359 {
360 return __virtio16_to_cpu(tun_is_little_endian(tun), val);
361 }
362
363 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
364 {
365 return __cpu_to_virtio16(tun_is_little_endian(tun), val);
366 }
367
368 static inline u32 tun_hashfn(u32 rxhash)
369 {
370 return rxhash & 0x3ff;
371 }
372
373 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
374 {
375 struct tun_flow_entry *e;
376
377 hlist_for_each_entry_rcu(e, head, hash_link) {
378 if (e->rxhash == rxhash)
379 return e;
380 }
381 return NULL;
382 }
383
384 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
385 struct hlist_head *head,
386 u32 rxhash, u16 queue_index)
387 {
388 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
389
390 if (e) {
391 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
392 rxhash, queue_index);
393 e->updated = jiffies;
394 e->rxhash = rxhash;
395 e->rps_rxhash = 0;
396 e->queue_index = queue_index;
397 e->tun = tun;
398 hlist_add_head_rcu(&e->hash_link, head);
399 ++tun->flow_count;
400 }
401 return e;
402 }
403
404 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
405 {
406 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
407 e->rxhash, e->queue_index);
408 hlist_del_rcu(&e->hash_link);
409 kfree_rcu(e, rcu);
410 --tun->flow_count;
411 }
412
413 static void tun_flow_flush(struct tun_struct *tun)
414 {
415 int i;
416
417 spin_lock_bh(&tun->lock);
418 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
419 struct tun_flow_entry *e;
420 struct hlist_node *n;
421
422 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
423 tun_flow_delete(tun, e);
424 }
425 spin_unlock_bh(&tun->lock);
426 }
427
428 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
429 {
430 int i;
431
432 spin_lock_bh(&tun->lock);
433 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
434 struct tun_flow_entry *e;
435 struct hlist_node *n;
436
437 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
438 if (e->queue_index == queue_index)
439 tun_flow_delete(tun, e);
440 }
441 }
442 spin_unlock_bh(&tun->lock);
443 }
444
445 static void tun_flow_cleanup(unsigned long data)
446 {
447 struct tun_struct *tun = (struct tun_struct *)data;
448 unsigned long delay = tun->ageing_time;
449 unsigned long next_timer = jiffies + delay;
450 unsigned long count = 0;
451 int i;
452
453 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
454
455 spin_lock_bh(&tun->lock);
456 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
457 struct tun_flow_entry *e;
458 struct hlist_node *n;
459
460 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
461 unsigned long this_timer;
462 count++;
463 this_timer = e->updated + delay;
464 if (time_before_eq(this_timer, jiffies))
465 tun_flow_delete(tun, e);
466 else if (time_before(this_timer, next_timer))
467 next_timer = this_timer;
468 }
469 }
470
471 if (count)
472 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
473 spin_unlock_bh(&tun->lock);
474 }
475
476 static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
477 struct tun_file *tfile)
478 {
479 struct hlist_head *head;
480 struct tun_flow_entry *e;
481 unsigned long delay = tun->ageing_time;
482 u16 queue_index = tfile->queue_index;
483
484 if (!rxhash)
485 return;
486 else
487 head = &tun->flows[tun_hashfn(rxhash)];
488
489 rcu_read_lock();
490
491 /* We may get a very small possibility of OOO during switching, not
492 * worth to optimize.*/
493 if (tun->numqueues == 1 || tfile->detached)
494 goto unlock;
495
496 e = tun_flow_find(head, rxhash);
497 if (likely(e)) {
498 /* TODO: keep queueing to old queue until it's empty? */
499 e->queue_index = queue_index;
500 e->updated = jiffies;
501 sock_rps_record_flow_hash(e->rps_rxhash);
502 } else {
503 spin_lock_bh(&tun->lock);
504 if (!tun_flow_find(head, rxhash) &&
505 tun->flow_count < MAX_TAP_FLOWS)
506 tun_flow_create(tun, head, rxhash, queue_index);
507
508 if (!timer_pending(&tun->flow_gc_timer))
509 mod_timer(&tun->flow_gc_timer,
510 round_jiffies_up(jiffies + delay));
511 spin_unlock_bh(&tun->lock);
512 }
513
514 unlock:
515 rcu_read_unlock();
516 }
517
518 /**
519 * Save the hash received in the stack receive path and update the
520 * flow_hash table accordingly.
521 */
522 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
523 {
524 if (unlikely(e->rps_rxhash != hash))
525 e->rps_rxhash = hash;
526 }
527
528 /* We try to identify a flow through its rxhash first. The reason that
529 * we do not check rxq no. is because some cards(e.g 82599), chooses
530 * the rxq based on the txq where the last packet of the flow comes. As
531 * the userspace application move between processors, we may get a
532 * different rxq no. here. If we could not get rxhash, then we would
533 * hope the rxq no. may help here.
534 */
535 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
536 void *accel_priv, select_queue_fallback_t fallback)
537 {
538 struct tun_struct *tun = netdev_priv(dev);
539 struct tun_flow_entry *e;
540 u32 txq = 0;
541 u32 numqueues = 0;
542
543 rcu_read_lock();
544 numqueues = ACCESS_ONCE(tun->numqueues);
545
546 txq = __skb_get_hash_symmetric(skb);
547 if (txq) {
548 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
549 if (e) {
550 tun_flow_save_rps_rxhash(e, txq);
551 txq = e->queue_index;
552 } else
553 /* use multiply and shift instead of expensive divide */
554 txq = ((u64)txq * numqueues) >> 32;
555 } else if (likely(skb_rx_queue_recorded(skb))) {
556 txq = skb_get_rx_queue(skb);
557 while (unlikely(txq >= numqueues))
558 txq -= numqueues;
559 }
560
561 rcu_read_unlock();
562 return txq;
563 }
564
565 static inline bool tun_not_capable(struct tun_struct *tun)
566 {
567 const struct cred *cred = current_cred();
568 struct net *net = dev_net(tun->dev);
569
570 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
571 (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
572 !ns_capable(net->user_ns, CAP_NET_ADMIN);
573 }
574
575 static void tun_set_real_num_queues(struct tun_struct *tun)
576 {
577 netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
578 netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
579 }
580
581 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
582 {
583 tfile->detached = tun;
584 list_add_tail(&tfile->next, &tun->disabled);
585 ++tun->numdisabled;
586 }
587
588 static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
589 {
590 struct tun_struct *tun = tfile->detached;
591
592 tfile->detached = NULL;
593 list_del_init(&tfile->next);
594 --tun->numdisabled;
595 return tun;
596 }
597
598 static void tun_queue_purge(struct tun_file *tfile)
599 {
600 struct sk_buff *skb;
601
602 while ((skb = skb_array_consume(&tfile->tx_array)) != NULL)
603 kfree_skb(skb);
604
605 skb_queue_purge(&tfile->sk.sk_write_queue);
606 skb_queue_purge(&tfile->sk.sk_error_queue);
607 }
608
609 static void __tun_detach(struct tun_file *tfile, bool clean)
610 {
611 struct tun_file *ntfile;
612 struct tun_struct *tun;
613
614 tun = rtnl_dereference(tfile->tun);
615
616 if (tun && clean) {
617 tun_napi_disable(tun, tfile);
618 tun_napi_del(tun, tfile);
619 }
620
621 if (tun && !tfile->detached) {
622 u16 index = tfile->queue_index;
623 BUG_ON(index >= tun->numqueues);
624
625 rcu_assign_pointer(tun->tfiles[index],
626 tun->tfiles[tun->numqueues - 1]);
627 ntfile = rtnl_dereference(tun->tfiles[index]);
628 ntfile->queue_index = index;
629
630 --tun->numqueues;
631 if (clean) {
632 RCU_INIT_POINTER(tfile->tun, NULL);
633 sock_put(&tfile->sk);
634 } else
635 tun_disable_queue(tun, tfile);
636
637 synchronize_net();
638 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
639 /* Drop read queue */
640 tun_queue_purge(tfile);
641 tun_set_real_num_queues(tun);
642 } else if (tfile->detached && clean) {
643 tun = tun_enable_queue(tfile);
644 sock_put(&tfile->sk);
645 }
646
647 if (clean) {
648 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
649 netif_carrier_off(tun->dev);
650
651 if (!(tun->flags & IFF_PERSIST) &&
652 tun->dev->reg_state == NETREG_REGISTERED)
653 unregister_netdevice(tun->dev);
654 }
655 if (tun)
656 skb_array_cleanup(&tfile->tx_array);
657 sock_put(&tfile->sk);
658 }
659 }
660
661 static void tun_detach(struct tun_file *tfile, bool clean)
662 {
663 rtnl_lock();
664 __tun_detach(tfile, clean);
665 rtnl_unlock();
666 }
667
668 static void tun_detach_all(struct net_device *dev)
669 {
670 struct tun_struct *tun = netdev_priv(dev);
671 struct bpf_prog *xdp_prog = rtnl_dereference(tun->xdp_prog);
672 struct tun_file *tfile, *tmp;
673 int i, n = tun->numqueues;
674
675 for (i = 0; i < n; i++) {
676 tfile = rtnl_dereference(tun->tfiles[i]);
677 BUG_ON(!tfile);
678 tun_napi_disable(tun, tfile);
679 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
680 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
681 RCU_INIT_POINTER(tfile->tun, NULL);
682 --tun->numqueues;
683 }
684 list_for_each_entry(tfile, &tun->disabled, next) {
685 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
686 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
687 RCU_INIT_POINTER(tfile->tun, NULL);
688 }
689 BUG_ON(tun->numqueues != 0);
690
691 synchronize_net();
692 for (i = 0; i < n; i++) {
693 tfile = rtnl_dereference(tun->tfiles[i]);
694 tun_napi_del(tun, tfile);
695 /* Drop read queue */
696 tun_queue_purge(tfile);
697 sock_put(&tfile->sk);
698 }
699 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
700 tun_enable_queue(tfile);
701 tun_queue_purge(tfile);
702 sock_put(&tfile->sk);
703 }
704 BUG_ON(tun->numdisabled != 0);
705
706 if (xdp_prog)
707 bpf_prog_put(xdp_prog);
708
709 if (tun->flags & IFF_PERSIST)
710 module_put(THIS_MODULE);
711 }
712
713 static int tun_attach(struct tun_struct *tun, struct file *file,
714 bool skip_filter, bool napi)
715 {
716 struct tun_file *tfile = file->private_data;
717 struct net_device *dev = tun->dev;
718 int err;
719
720 err = security_tun_dev_attach(tfile->socket.sk, tun->security);
721 if (err < 0)
722 goto out;
723
724 err = -EINVAL;
725 if (rtnl_dereference(tfile->tun) && !tfile->detached)
726 goto out;
727
728 err = -EBUSY;
729 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
730 goto out;
731
732 err = -E2BIG;
733 if (!tfile->detached &&
734 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
735 goto out;
736
737 err = 0;
738
739 /* Re-attach the filter to persist device */
740 if (!skip_filter && (tun->filter_attached == true)) {
741 lock_sock(tfile->socket.sk);
742 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
743 release_sock(tfile->socket.sk);
744 if (!err)
745 goto out;
746 }
747
748 if (!tfile->detached &&
749 skb_array_init(&tfile->tx_array, dev->tx_queue_len, GFP_KERNEL)) {
750 err = -ENOMEM;
751 goto out;
752 }
753
754 tfile->queue_index = tun->numqueues;
755 tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
756 rcu_assign_pointer(tfile->tun, tun);
757 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
758 tun->numqueues++;
759
760 if (tfile->detached) {
761 tun_enable_queue(tfile);
762 } else {
763 sock_hold(&tfile->sk);
764 tun_napi_init(tun, tfile, napi);
765 }
766
767 tun_set_real_num_queues(tun);
768
769 /* device is allowed to go away first, so no need to hold extra
770 * refcnt.
771 */
772
773 out:
774 return err;
775 }
776
777 static struct tun_struct *tun_get(struct tun_file *tfile)
778 {
779 struct tun_struct *tun;
780
781 rcu_read_lock();
782 tun = rcu_dereference(tfile->tun);
783 if (tun)
784 dev_hold(tun->dev);
785 rcu_read_unlock();
786
787 return tun;
788 }
789
790 static void tun_put(struct tun_struct *tun)
791 {
792 dev_put(tun->dev);
793 }
794
795 /* TAP filtering */
796 static void addr_hash_set(u32 *mask, const u8 *addr)
797 {
798 int n = ether_crc(ETH_ALEN, addr) >> 26;
799 mask[n >> 5] |= (1 << (n & 31));
800 }
801
802 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
803 {
804 int n = ether_crc(ETH_ALEN, addr) >> 26;
805 return mask[n >> 5] & (1 << (n & 31));
806 }
807
808 static int update_filter(struct tap_filter *filter, void __user *arg)
809 {
810 struct { u8 u[ETH_ALEN]; } *addr;
811 struct tun_filter uf;
812 int err, alen, n, nexact;
813
814 if (copy_from_user(&uf, arg, sizeof(uf)))
815 return -EFAULT;
816
817 if (!uf.count) {
818 /* Disabled */
819 filter->count = 0;
820 return 0;
821 }
822
823 alen = ETH_ALEN * uf.count;
824 addr = memdup_user(arg + sizeof(uf), alen);
825 if (IS_ERR(addr))
826 return PTR_ERR(addr);
827
828 /* The filter is updated without holding any locks. Which is
829 * perfectly safe. We disable it first and in the worst
830 * case we'll accept a few undesired packets. */
831 filter->count = 0;
832 wmb();
833
834 /* Use first set of addresses as an exact filter */
835 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
836 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
837
838 nexact = n;
839
840 /* Remaining multicast addresses are hashed,
841 * unicast will leave the filter disabled. */
842 memset(filter->mask, 0, sizeof(filter->mask));
843 for (; n < uf.count; n++) {
844 if (!is_multicast_ether_addr(addr[n].u)) {
845 err = 0; /* no filter */
846 goto free_addr;
847 }
848 addr_hash_set(filter->mask, addr[n].u);
849 }
850
851 /* For ALLMULTI just set the mask to all ones.
852 * This overrides the mask populated above. */
853 if ((uf.flags & TUN_FLT_ALLMULTI))
854 memset(filter->mask, ~0, sizeof(filter->mask));
855
856 /* Now enable the filter */
857 wmb();
858 filter->count = nexact;
859
860 /* Return the number of exact filters */
861 err = nexact;
862 free_addr:
863 kfree(addr);
864 return err;
865 }
866
867 /* Returns: 0 - drop, !=0 - accept */
868 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
869 {
870 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
871 * at this point. */
872 struct ethhdr *eh = (struct ethhdr *) skb->data;
873 int i;
874
875 /* Exact match */
876 for (i = 0; i < filter->count; i++)
877 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
878 return 1;
879
880 /* Inexact match (multicast only) */
881 if (is_multicast_ether_addr(eh->h_dest))
882 return addr_hash_test(filter->mask, eh->h_dest);
883
884 return 0;
885 }
886
887 /*
888 * Checks whether the packet is accepted or not.
889 * Returns: 0 - drop, !=0 - accept
890 */
891 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
892 {
893 if (!filter->count)
894 return 1;
895
896 return run_filter(filter, skb);
897 }
898
899 /* Network device part of the driver */
900
901 static const struct ethtool_ops tun_ethtool_ops;
902
903 /* Net device detach from fd. */
904 static void tun_net_uninit(struct net_device *dev)
905 {
906 tun_detach_all(dev);
907 }
908
909 /* Net device open. */
910 static int tun_net_open(struct net_device *dev)
911 {
912 struct tun_struct *tun = netdev_priv(dev);
913 int i;
914
915 netif_tx_start_all_queues(dev);
916
917 for (i = 0; i < tun->numqueues; i++) {
918 struct tun_file *tfile;
919
920 tfile = rtnl_dereference(tun->tfiles[i]);
921 tfile->socket.sk->sk_write_space(tfile->socket.sk);
922 }
923
924 return 0;
925 }
926
927 /* Net device close. */
928 static int tun_net_close(struct net_device *dev)
929 {
930 netif_tx_stop_all_queues(dev);
931 return 0;
932 }
933
934 /* Net device start xmit */
935 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
936 {
937 struct tun_struct *tun = netdev_priv(dev);
938 int txq = skb->queue_mapping;
939 struct tun_file *tfile;
940 u32 numqueues = 0;
941
942 rcu_read_lock();
943 tfile = rcu_dereference(tun->tfiles[txq]);
944 numqueues = ACCESS_ONCE(tun->numqueues);
945
946 /* Drop packet if interface is not attached */
947 if (txq >= numqueues)
948 goto drop;
949
950 #ifdef CONFIG_RPS
951 if (numqueues == 1 && static_key_false(&rps_needed)) {
952 /* Select queue was not called for the skbuff, so we extract the
953 * RPS hash and save it into the flow_table here.
954 */
955 __u32 rxhash;
956
957 rxhash = __skb_get_hash_symmetric(skb);
958 if (rxhash) {
959 struct tun_flow_entry *e;
960 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)],
961 rxhash);
962 if (e)
963 tun_flow_save_rps_rxhash(e, rxhash);
964 }
965 }
966 #endif
967
968 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
969
970 BUG_ON(!tfile);
971
972 /* Drop if the filter does not like it.
973 * This is a noop if the filter is disabled.
974 * Filter can be enabled only for the TAP devices. */
975 if (!check_filter(&tun->txflt, skb))
976 goto drop;
977
978 if (tfile->socket.sk->sk_filter &&
979 sk_filter(tfile->socket.sk, skb))
980 goto drop;
981
982 if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC)))
983 goto drop;
984
985 skb_tx_timestamp(skb);
986
987 /* Orphan the skb - required as we might hang on to it
988 * for indefinite time.
989 */
990 skb_orphan(skb);
991
992 nf_reset(skb);
993
994 if (skb_array_produce(&tfile->tx_array, skb))
995 goto drop;
996
997 /* Notify and wake up reader process */
998 if (tfile->flags & TUN_FASYNC)
999 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1000 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1001
1002 rcu_read_unlock();
1003 return NETDEV_TX_OK;
1004
1005 drop:
1006 this_cpu_inc(tun->pcpu_stats->tx_dropped);
1007 skb_tx_error(skb);
1008 kfree_skb(skb);
1009 rcu_read_unlock();
1010 return NET_XMIT_DROP;
1011 }
1012
1013 static void tun_net_mclist(struct net_device *dev)
1014 {
1015 /*
1016 * This callback is supposed to deal with mc filter in
1017 * _rx_ path and has nothing to do with the _tx_ path.
1018 * In rx path we always accept everything userspace gives us.
1019 */
1020 }
1021
1022 static netdev_features_t tun_net_fix_features(struct net_device *dev,
1023 netdev_features_t features)
1024 {
1025 struct tun_struct *tun = netdev_priv(dev);
1026
1027 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
1028 }
1029 #ifdef CONFIG_NET_POLL_CONTROLLER
1030 static void tun_poll_controller(struct net_device *dev)
1031 {
1032 /*
1033 * Tun only receives frames when:
1034 * 1) the char device endpoint gets data from user space
1035 * 2) the tun socket gets a sendmsg call from user space
1036 * If NAPI is not enabled, since both of those are synchronous
1037 * operations, we are guaranteed never to have pending data when we poll
1038 * for it so there is nothing to do here but return.
1039 * We need this though so netpoll recognizes us as an interface that
1040 * supports polling, which enables bridge devices in virt setups to
1041 * still use netconsole
1042 * If NAPI is enabled, however, we need to schedule polling for all
1043 * queues unless we are using napi_gro_frags(), which we call in
1044 * process context and not in NAPI context.
1045 */
1046 struct tun_struct *tun = netdev_priv(dev);
1047
1048 if (tun->flags & IFF_NAPI) {
1049 struct tun_file *tfile;
1050 int i;
1051
1052 if (tun_napi_frags_enabled(tun))
1053 return;
1054
1055 rcu_read_lock();
1056 for (i = 0; i < tun->numqueues; i++) {
1057 tfile = rcu_dereference(tun->tfiles[i]);
1058 napi_schedule(&tfile->napi);
1059 }
1060 rcu_read_unlock();
1061 }
1062 return;
1063 }
1064 #endif
1065
1066 static void tun_set_headroom(struct net_device *dev, int new_hr)
1067 {
1068 struct tun_struct *tun = netdev_priv(dev);
1069
1070 if (new_hr < NET_SKB_PAD)
1071 new_hr = NET_SKB_PAD;
1072
1073 tun->align = new_hr;
1074 }
1075
1076 static void
1077 tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
1078 {
1079 u32 rx_dropped = 0, tx_dropped = 0, rx_frame_errors = 0;
1080 struct tun_struct *tun = netdev_priv(dev);
1081 struct tun_pcpu_stats *p;
1082 int i;
1083
1084 for_each_possible_cpu(i) {
1085 u64 rxpackets, rxbytes, txpackets, txbytes;
1086 unsigned int start;
1087
1088 p = per_cpu_ptr(tun->pcpu_stats, i);
1089 do {
1090 start = u64_stats_fetch_begin(&p->syncp);
1091 rxpackets = p->rx_packets;
1092 rxbytes = p->rx_bytes;
1093 txpackets = p->tx_packets;
1094 txbytes = p->tx_bytes;
1095 } while (u64_stats_fetch_retry(&p->syncp, start));
1096
1097 stats->rx_packets += rxpackets;
1098 stats->rx_bytes += rxbytes;
1099 stats->tx_packets += txpackets;
1100 stats->tx_bytes += txbytes;
1101
1102 /* u32 counters */
1103 rx_dropped += p->rx_dropped;
1104 rx_frame_errors += p->rx_frame_errors;
1105 tx_dropped += p->tx_dropped;
1106 }
1107 stats->rx_dropped = rx_dropped;
1108 stats->rx_frame_errors = rx_frame_errors;
1109 stats->tx_dropped = tx_dropped;
1110 }
1111
1112 static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1113 struct netlink_ext_ack *extack)
1114 {
1115 struct tun_struct *tun = netdev_priv(dev);
1116 struct bpf_prog *old_prog;
1117
1118 old_prog = rtnl_dereference(tun->xdp_prog);
1119 rcu_assign_pointer(tun->xdp_prog, prog);
1120 if (old_prog)
1121 bpf_prog_put(old_prog);
1122
1123 return 0;
1124 }
1125
1126 static u32 tun_xdp_query(struct net_device *dev)
1127 {
1128 struct tun_struct *tun = netdev_priv(dev);
1129 const struct bpf_prog *xdp_prog;
1130
1131 xdp_prog = rtnl_dereference(tun->xdp_prog);
1132 if (xdp_prog)
1133 return xdp_prog->aux->id;
1134
1135 return 0;
1136 }
1137
1138 static int tun_xdp(struct net_device *dev, struct netdev_xdp *xdp)
1139 {
1140 switch (xdp->command) {
1141 case XDP_SETUP_PROG:
1142 return tun_xdp_set(dev, xdp->prog, xdp->extack);
1143 case XDP_QUERY_PROG:
1144 xdp->prog_id = tun_xdp_query(dev);
1145 xdp->prog_attached = !!xdp->prog_id;
1146 return 0;
1147 default:
1148 return -EINVAL;
1149 }
1150 }
1151
1152 static const struct net_device_ops tun_netdev_ops = {
1153 .ndo_uninit = tun_net_uninit,
1154 .ndo_open = tun_net_open,
1155 .ndo_stop = tun_net_close,
1156 .ndo_start_xmit = tun_net_xmit,
1157 .ndo_fix_features = tun_net_fix_features,
1158 .ndo_select_queue = tun_select_queue,
1159 #ifdef CONFIG_NET_POLL_CONTROLLER
1160 .ndo_poll_controller = tun_poll_controller,
1161 #endif
1162 .ndo_set_rx_headroom = tun_set_headroom,
1163 .ndo_get_stats64 = tun_net_get_stats64,
1164 };
1165
1166 static const struct net_device_ops tap_netdev_ops = {
1167 .ndo_uninit = tun_net_uninit,
1168 .ndo_open = tun_net_open,
1169 .ndo_stop = tun_net_close,
1170 .ndo_start_xmit = tun_net_xmit,
1171 .ndo_fix_features = tun_net_fix_features,
1172 .ndo_set_rx_mode = tun_net_mclist,
1173 .ndo_set_mac_address = eth_mac_addr,
1174 .ndo_validate_addr = eth_validate_addr,
1175 .ndo_select_queue = tun_select_queue,
1176 #ifdef CONFIG_NET_POLL_CONTROLLER
1177 .ndo_poll_controller = tun_poll_controller,
1178 #endif
1179 .ndo_features_check = passthru_features_check,
1180 .ndo_set_rx_headroom = tun_set_headroom,
1181 .ndo_get_stats64 = tun_net_get_stats64,
1182 .ndo_xdp = tun_xdp,
1183 };
1184
1185 static void tun_flow_init(struct tun_struct *tun)
1186 {
1187 int i;
1188
1189 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1190 INIT_HLIST_HEAD(&tun->flows[i]);
1191
1192 tun->ageing_time = TUN_FLOW_EXPIRE;
1193 setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun);
1194 mod_timer(&tun->flow_gc_timer,
1195 round_jiffies_up(jiffies + tun->ageing_time));
1196 }
1197
1198 static void tun_flow_uninit(struct tun_struct *tun)
1199 {
1200 del_timer_sync(&tun->flow_gc_timer);
1201 tun_flow_flush(tun);
1202 }
1203
1204 #define MIN_MTU 68
1205 #define MAX_MTU 65535
1206
1207 /* Initialize net device. */
1208 static void tun_net_init(struct net_device *dev)
1209 {
1210 struct tun_struct *tun = netdev_priv(dev);
1211
1212 switch (tun->flags & TUN_TYPE_MASK) {
1213 case IFF_TUN:
1214 dev->netdev_ops = &tun_netdev_ops;
1215
1216 /* Point-to-Point TUN Device */
1217 dev->hard_header_len = 0;
1218 dev->addr_len = 0;
1219 dev->mtu = 1500;
1220
1221 /* Zero header length */
1222 dev->type = ARPHRD_NONE;
1223 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1224 break;
1225
1226 case IFF_TAP:
1227 dev->netdev_ops = &tap_netdev_ops;
1228 /* Ethernet TAP Device */
1229 ether_setup(dev);
1230 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1231 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1232
1233 eth_hw_addr_random(dev);
1234
1235 break;
1236 }
1237
1238 dev->min_mtu = MIN_MTU;
1239 dev->max_mtu = MAX_MTU - dev->hard_header_len;
1240 }
1241
1242 /* Character device part */
1243
1244 /* Poll */
1245 static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
1246 {
1247 struct tun_file *tfile = file->private_data;
1248 struct tun_struct *tun = tun_get(tfile);
1249 struct sock *sk;
1250 unsigned int mask = 0;
1251
1252 if (!tun)
1253 return POLLERR;
1254
1255 sk = tfile->socket.sk;
1256
1257 tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
1258
1259 poll_wait(file, sk_sleep(sk), wait);
1260
1261 if (!skb_array_empty(&tfile->tx_array))
1262 mask |= POLLIN | POLLRDNORM;
1263
1264 if (tun->dev->flags & IFF_UP &&
1265 (sock_writeable(sk) ||
1266 (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1267 sock_writeable(sk))))
1268 mask |= POLLOUT | POLLWRNORM;
1269
1270 if (tun->dev->reg_state != NETREG_REGISTERED)
1271 mask = POLLERR;
1272
1273 tun_put(tun);
1274 return mask;
1275 }
1276
1277 static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile,
1278 size_t len,
1279 const struct iov_iter *it)
1280 {
1281 struct sk_buff *skb;
1282 size_t linear;
1283 int err;
1284 int i;
1285
1286 if (it->nr_segs > MAX_SKB_FRAGS + 1)
1287 return ERR_PTR(-ENOMEM);
1288
1289 local_bh_disable();
1290 skb = napi_get_frags(&tfile->napi);
1291 local_bh_enable();
1292 if (!skb)
1293 return ERR_PTR(-ENOMEM);
1294
1295 linear = iov_iter_single_seg_count(it);
1296 err = __skb_grow(skb, linear);
1297 if (err)
1298 goto free;
1299
1300 skb->len = len;
1301 skb->data_len = len - linear;
1302 skb->truesize += skb->data_len;
1303
1304 for (i = 1; i < it->nr_segs; i++) {
1305 size_t fragsz = it->iov[i].iov_len;
1306 unsigned long offset;
1307 struct page *page;
1308 void *data;
1309
1310 if (fragsz == 0 || fragsz > PAGE_SIZE) {
1311 err = -EINVAL;
1312 goto free;
1313 }
1314
1315 local_bh_disable();
1316 data = napi_alloc_frag(fragsz);
1317 local_bh_enable();
1318 if (!data) {
1319 err = -ENOMEM;
1320 goto free;
1321 }
1322
1323 page = virt_to_head_page(data);
1324 offset = data - page_address(page);
1325 skb_fill_page_desc(skb, i - 1, page, offset, fragsz);
1326 }
1327
1328 return skb;
1329 free:
1330 /* frees skb and all frags allocated with napi_alloc_frag() */
1331 napi_free_frags(&tfile->napi);
1332 return ERR_PTR(err);
1333 }
1334
1335 /* prepad is the amount to reserve at front. len is length after that.
1336 * linear is a hint as to how much to copy (usually headers). */
1337 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1338 size_t prepad, size_t len,
1339 size_t linear, int noblock)
1340 {
1341 struct sock *sk = tfile->socket.sk;
1342 struct sk_buff *skb;
1343 int err;
1344
1345 /* Under a page? Don't bother with paged skb. */
1346 if (prepad + len < PAGE_SIZE || !linear)
1347 linear = len;
1348
1349 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1350 &err, 0);
1351 if (!skb)
1352 return ERR_PTR(err);
1353
1354 skb_reserve(skb, prepad);
1355 skb_put(skb, linear);
1356 skb->data_len = len - linear;
1357 skb->len += len - linear;
1358
1359 return skb;
1360 }
1361
1362 static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile,
1363 struct sk_buff *skb, int more)
1364 {
1365 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1366 struct sk_buff_head process_queue;
1367 u32 rx_batched = tun->rx_batched;
1368 bool rcv = false;
1369
1370 if (!rx_batched || (!more && skb_queue_empty(queue))) {
1371 local_bh_disable();
1372 netif_receive_skb(skb);
1373 local_bh_enable();
1374 return;
1375 }
1376
1377 spin_lock(&queue->lock);
1378 if (!more || skb_queue_len(queue) == rx_batched) {
1379 __skb_queue_head_init(&process_queue);
1380 skb_queue_splice_tail_init(queue, &process_queue);
1381 rcv = true;
1382 } else {
1383 __skb_queue_tail(queue, skb);
1384 }
1385 spin_unlock(&queue->lock);
1386
1387 if (rcv) {
1388 struct sk_buff *nskb;
1389
1390 local_bh_disable();
1391 while ((nskb = __skb_dequeue(&process_queue)))
1392 netif_receive_skb(nskb);
1393 netif_receive_skb(skb);
1394 local_bh_enable();
1395 }
1396 }
1397
1398 static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile,
1399 int len, int noblock, bool zerocopy)
1400 {
1401 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
1402 return false;
1403
1404 if (tfile->socket.sk->sk_sndbuf != INT_MAX)
1405 return false;
1406
1407 if (!noblock)
1408 return false;
1409
1410 if (zerocopy)
1411 return false;
1412
1413 if (SKB_DATA_ALIGN(len + TUN_RX_PAD) +
1414 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
1415 return false;
1416
1417 return true;
1418 }
1419
1420 static struct sk_buff *tun_build_skb(struct tun_struct *tun,
1421 struct tun_file *tfile,
1422 struct iov_iter *from,
1423 struct virtio_net_hdr *hdr,
1424 int len, int *skb_xdp)
1425 {
1426 struct page_frag *alloc_frag = &current->task_frag;
1427 struct sk_buff *skb;
1428 struct bpf_prog *xdp_prog;
1429 int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1430 unsigned int delta = 0;
1431 char *buf;
1432 size_t copied;
1433 bool xdp_xmit = false;
1434 int err, pad = TUN_RX_PAD;
1435
1436 rcu_read_lock();
1437 xdp_prog = rcu_dereference(tun->xdp_prog);
1438 if (xdp_prog)
1439 pad += TUN_HEADROOM;
1440 buflen += SKB_DATA_ALIGN(len + pad);
1441 rcu_read_unlock();
1442
1443 if (unlikely(!skb_page_frag_refill(buflen, alloc_frag, GFP_KERNEL)))
1444 return ERR_PTR(-ENOMEM);
1445
1446 buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
1447 copied = copy_page_from_iter(alloc_frag->page,
1448 alloc_frag->offset + pad,
1449 len, from);
1450 if (copied != len)
1451 return ERR_PTR(-EFAULT);
1452
1453 /* There's a small window that XDP may be set after the check
1454 * of xdp_prog above, this should be rare and for simplicity
1455 * we do XDP on skb in case the headroom is not enough.
1456 */
1457 if (hdr->gso_type || !xdp_prog)
1458 *skb_xdp = 1;
1459 else
1460 *skb_xdp = 0;
1461
1462 rcu_read_lock();
1463 xdp_prog = rcu_dereference(tun->xdp_prog);
1464 if (xdp_prog && !*skb_xdp) {
1465 struct xdp_buff xdp;
1466 void *orig_data;
1467 u32 act;
1468
1469 xdp.data_hard_start = buf;
1470 xdp.data = buf + pad;
1471 xdp_set_data_meta_invalid(&xdp);
1472 xdp.data_end = xdp.data + len;
1473 orig_data = xdp.data;
1474 act = bpf_prog_run_xdp(xdp_prog, &xdp);
1475
1476 switch (act) {
1477 case XDP_REDIRECT:
1478 get_page(alloc_frag->page);
1479 alloc_frag->offset += buflen;
1480 err = xdp_do_redirect(tun->dev, &xdp, xdp_prog);
1481 if (err)
1482 goto err_redirect;
1483 return NULL;
1484 case XDP_TX:
1485 xdp_xmit = true;
1486 /* fall through */
1487 case XDP_PASS:
1488 delta = orig_data - xdp.data;
1489 break;
1490 default:
1491 bpf_warn_invalid_xdp_action(act);
1492 /* fall through */
1493 case XDP_ABORTED:
1494 trace_xdp_exception(tun->dev, xdp_prog, act);
1495 /* fall through */
1496 case XDP_DROP:
1497 goto err_xdp;
1498 }
1499 }
1500
1501 skb = build_skb(buf, buflen);
1502 if (!skb) {
1503 rcu_read_unlock();
1504 return ERR_PTR(-ENOMEM);
1505 }
1506
1507 skb_reserve(skb, pad - delta);
1508 skb_put(skb, len + delta);
1509 get_page(alloc_frag->page);
1510 alloc_frag->offset += buflen;
1511
1512 if (xdp_xmit) {
1513 skb->dev = tun->dev;
1514 generic_xdp_tx(skb, xdp_prog);
1515 rcu_read_lock();
1516 return NULL;
1517 }
1518
1519 rcu_read_unlock();
1520
1521 return skb;
1522
1523 err_redirect:
1524 put_page(alloc_frag->page);
1525 err_xdp:
1526 rcu_read_unlock();
1527 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1528 return NULL;
1529 }
1530
1531 /* Get packet from user space buffer */
1532 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1533 void *msg_control, struct iov_iter *from,
1534 int noblock, bool more)
1535 {
1536 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1537 struct sk_buff *skb;
1538 size_t total_len = iov_iter_count(from);
1539 size_t len = total_len, align = tun->align, linear;
1540 struct virtio_net_hdr gso = { 0 };
1541 struct tun_pcpu_stats *stats;
1542 int good_linear;
1543 int copylen;
1544 bool zerocopy = false;
1545 int err;
1546 u32 rxhash;
1547 int skb_xdp = 1;
1548 bool frags = tun_napi_frags_enabled(tun);
1549
1550 if (!(tun->dev->flags & IFF_UP))
1551 return -EIO;
1552
1553 if (!(tun->flags & IFF_NO_PI)) {
1554 if (len < sizeof(pi))
1555 return -EINVAL;
1556 len -= sizeof(pi);
1557
1558 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1559 return -EFAULT;
1560 }
1561
1562 if (tun->flags & IFF_VNET_HDR) {
1563 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1564
1565 if (len < vnet_hdr_sz)
1566 return -EINVAL;
1567 len -= vnet_hdr_sz;
1568
1569 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1570 return -EFAULT;
1571
1572 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1573 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1574 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1575
1576 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1577 return -EINVAL;
1578 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1579 }
1580
1581 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1582 align += NET_IP_ALIGN;
1583 if (unlikely(len < ETH_HLEN ||
1584 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1585 return -EINVAL;
1586 }
1587
1588 good_linear = SKB_MAX_HEAD(align);
1589
1590 if (msg_control) {
1591 struct iov_iter i = *from;
1592
1593 /* There are 256 bytes to be copied in skb, so there is
1594 * enough room for skb expand head in case it is used.
1595 * The rest of the buffer is mapped from userspace.
1596 */
1597 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1598 if (copylen > good_linear)
1599 copylen = good_linear;
1600 linear = copylen;
1601 iov_iter_advance(&i, copylen);
1602 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1603 zerocopy = true;
1604 }
1605
1606 if (!frags && tun_can_build_skb(tun, tfile, len, noblock, zerocopy)) {
1607 /* For the packet that is not easy to be processed
1608 * (e.g gso or jumbo packet), we will do it at after
1609 * skb was created with generic XDP routine.
1610 */
1611 skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp);
1612 if (IS_ERR(skb)) {
1613 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1614 return PTR_ERR(skb);
1615 }
1616 if (!skb)
1617 return total_len;
1618 } else {
1619 if (!zerocopy) {
1620 copylen = len;
1621 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1622 linear = good_linear;
1623 else
1624 linear = tun16_to_cpu(tun, gso.hdr_len);
1625 }
1626
1627 if (frags) {
1628 mutex_lock(&tfile->napi_mutex);
1629 skb = tun_napi_alloc_frags(tfile, copylen, from);
1630 /* tun_napi_alloc_frags() enforces a layout for the skb.
1631 * If zerocopy is enabled, then this layout will be
1632 * overwritten by zerocopy_sg_from_iter().
1633 */
1634 zerocopy = false;
1635 } else {
1636 skb = tun_alloc_skb(tfile, align, copylen, linear,
1637 noblock);
1638 }
1639
1640 if (IS_ERR(skb)) {
1641 if (PTR_ERR(skb) != -EAGAIN)
1642 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1643 if (frags)
1644 mutex_unlock(&tfile->napi_mutex);
1645 return PTR_ERR(skb);
1646 }
1647
1648 if (zerocopy)
1649 err = zerocopy_sg_from_iter(skb, from);
1650 else
1651 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1652
1653 if (err) {
1654 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1655 kfree_skb(skb);
1656 if (frags) {
1657 tfile->napi.skb = NULL;
1658 mutex_unlock(&tfile->napi_mutex);
1659 }
1660
1661 return -EFAULT;
1662 }
1663 }
1664
1665 if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1666 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
1667 kfree_skb(skb);
1668 if (frags) {
1669 tfile->napi.skb = NULL;
1670 mutex_unlock(&tfile->napi_mutex);
1671 }
1672
1673 return -EINVAL;
1674 }
1675
1676 switch (tun->flags & TUN_TYPE_MASK) {
1677 case IFF_TUN:
1678 if (tun->flags & IFF_NO_PI) {
1679 switch (skb->data[0] & 0xf0) {
1680 case 0x40:
1681 pi.proto = htons(ETH_P_IP);
1682 break;
1683 case 0x60:
1684 pi.proto = htons(ETH_P_IPV6);
1685 break;
1686 default:
1687 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1688 kfree_skb(skb);
1689 return -EINVAL;
1690 }
1691 }
1692
1693 skb_reset_mac_header(skb);
1694 skb->protocol = pi.proto;
1695 skb->dev = tun->dev;
1696 break;
1697 case IFF_TAP:
1698 if (!frags)
1699 skb->protocol = eth_type_trans(skb, tun->dev);
1700 break;
1701 }
1702
1703 /* copy skb_ubuf_info for callback when skb has no error */
1704 if (zerocopy) {
1705 skb_shinfo(skb)->destructor_arg = msg_control;
1706 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1707 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1708 } else if (msg_control) {
1709 struct ubuf_info *uarg = msg_control;
1710 uarg->callback(uarg, false);
1711 }
1712
1713 skb_reset_network_header(skb);
1714 skb_probe_transport_header(skb, 0);
1715
1716 if (skb_xdp) {
1717 struct bpf_prog *xdp_prog;
1718 int ret;
1719
1720 rcu_read_lock();
1721 xdp_prog = rcu_dereference(tun->xdp_prog);
1722 if (xdp_prog) {
1723 ret = do_xdp_generic(xdp_prog, skb);
1724 if (ret != XDP_PASS) {
1725 rcu_read_unlock();
1726 return total_len;
1727 }
1728 }
1729 rcu_read_unlock();
1730 }
1731
1732 rxhash = __skb_get_hash_symmetric(skb);
1733
1734 if (frags) {
1735 /* Exercise flow dissector code path. */
1736 u32 headlen = eth_get_headlen(skb->data, skb_headlen(skb));
1737
1738 if (headlen > skb_headlen(skb) || headlen < ETH_HLEN) {
1739 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1740 napi_free_frags(&tfile->napi);
1741 mutex_unlock(&tfile->napi_mutex);
1742 WARN_ON(1);
1743 return -ENOMEM;
1744 }
1745
1746 local_bh_disable();
1747 napi_gro_frags(&tfile->napi);
1748 local_bh_enable();
1749 mutex_unlock(&tfile->napi_mutex);
1750 } else if (tun->flags & IFF_NAPI) {
1751 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1752 int queue_len;
1753
1754 spin_lock_bh(&queue->lock);
1755 __skb_queue_tail(queue, skb);
1756 queue_len = skb_queue_len(queue);
1757 spin_unlock(&queue->lock);
1758
1759 if (!more || queue_len > NAPI_POLL_WEIGHT)
1760 napi_schedule(&tfile->napi);
1761
1762 local_bh_enable();
1763 } else if (!IS_ENABLED(CONFIG_4KSTACKS)) {
1764 tun_rx_batched(tun, tfile, skb, more);
1765 } else {
1766 netif_rx_ni(skb);
1767 }
1768
1769 stats = get_cpu_ptr(tun->pcpu_stats);
1770 u64_stats_update_begin(&stats->syncp);
1771 stats->rx_packets++;
1772 stats->rx_bytes += len;
1773 u64_stats_update_end(&stats->syncp);
1774 put_cpu_ptr(stats);
1775
1776 tun_flow_update(tun, rxhash, tfile);
1777 return total_len;
1778 }
1779
1780 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
1781 {
1782 struct file *file = iocb->ki_filp;
1783 struct tun_file *tfile = file->private_data;
1784 struct tun_struct *tun = tun_get(tfile);
1785 ssize_t result;
1786
1787 if (!tun)
1788 return -EBADFD;
1789
1790 result = tun_get_user(tun, tfile, NULL, from,
1791 file->f_flags & O_NONBLOCK, false);
1792
1793 tun_put(tun);
1794 return result;
1795 }
1796
1797 /* Put packet to the user space buffer */
1798 static ssize_t tun_put_user(struct tun_struct *tun,
1799 struct tun_file *tfile,
1800 struct sk_buff *skb,
1801 struct iov_iter *iter)
1802 {
1803 struct tun_pi pi = { 0, skb->protocol };
1804 struct tun_pcpu_stats *stats;
1805 ssize_t total;
1806 int vlan_offset = 0;
1807 int vlan_hlen = 0;
1808 int vnet_hdr_sz = 0;
1809
1810 if (skb_vlan_tag_present(skb))
1811 vlan_hlen = VLAN_HLEN;
1812
1813 if (tun->flags & IFF_VNET_HDR)
1814 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1815
1816 total = skb->len + vlan_hlen + vnet_hdr_sz;
1817
1818 if (!(tun->flags & IFF_NO_PI)) {
1819 if (iov_iter_count(iter) < sizeof(pi))
1820 return -EINVAL;
1821
1822 total += sizeof(pi);
1823 if (iov_iter_count(iter) < total) {
1824 /* Packet will be striped */
1825 pi.flags |= TUN_PKT_STRIP;
1826 }
1827
1828 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
1829 return -EFAULT;
1830 }
1831
1832 if (vnet_hdr_sz) {
1833 struct virtio_net_hdr gso;
1834
1835 if (iov_iter_count(iter) < vnet_hdr_sz)
1836 return -EINVAL;
1837
1838 if (virtio_net_hdr_from_skb(skb, &gso,
1839 tun_is_little_endian(tun), true)) {
1840 struct skb_shared_info *sinfo = skb_shinfo(skb);
1841 pr_err("unexpected GSO type: "
1842 "0x%x, gso_size %d, hdr_len %d\n",
1843 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
1844 tun16_to_cpu(tun, gso.hdr_len));
1845 print_hex_dump(KERN_ERR, "tun: ",
1846 DUMP_PREFIX_NONE,
1847 16, 1, skb->head,
1848 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
1849 WARN_ON_ONCE(1);
1850 return -EINVAL;
1851 }
1852
1853 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
1854 return -EFAULT;
1855
1856 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
1857 }
1858
1859 if (vlan_hlen) {
1860 int ret;
1861 struct {
1862 __be16 h_vlan_proto;
1863 __be16 h_vlan_TCI;
1864 } veth;
1865
1866 veth.h_vlan_proto = skb->vlan_proto;
1867 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
1868
1869 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
1870
1871 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
1872 if (ret || !iov_iter_count(iter))
1873 goto done;
1874
1875 ret = copy_to_iter(&veth, sizeof(veth), iter);
1876 if (ret != sizeof(veth) || !iov_iter_count(iter))
1877 goto done;
1878 }
1879
1880 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
1881
1882 done:
1883 /* caller is in process context, */
1884 stats = get_cpu_ptr(tun->pcpu_stats);
1885 u64_stats_update_begin(&stats->syncp);
1886 stats->tx_packets++;
1887 stats->tx_bytes += skb->len + vlan_hlen;
1888 u64_stats_update_end(&stats->syncp);
1889 put_cpu_ptr(tun->pcpu_stats);
1890
1891 return total;
1892 }
1893
1894 static struct sk_buff *tun_ring_recv(struct tun_file *tfile, int noblock,
1895 int *err)
1896 {
1897 DECLARE_WAITQUEUE(wait, current);
1898 struct sk_buff *skb = NULL;
1899 int error = 0;
1900
1901 skb = skb_array_consume(&tfile->tx_array);
1902 if (skb)
1903 goto out;
1904 if (noblock) {
1905 error = -EAGAIN;
1906 goto out;
1907 }
1908
1909 add_wait_queue(&tfile->wq.wait, &wait);
1910 current->state = TASK_INTERRUPTIBLE;
1911
1912 while (1) {
1913 skb = skb_array_consume(&tfile->tx_array);
1914 if (skb)
1915 break;
1916 if (signal_pending(current)) {
1917 error = -ERESTARTSYS;
1918 break;
1919 }
1920 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
1921 error = -EFAULT;
1922 break;
1923 }
1924
1925 schedule();
1926 }
1927
1928 current->state = TASK_RUNNING;
1929 remove_wait_queue(&tfile->wq.wait, &wait);
1930
1931 out:
1932 *err = error;
1933 return skb;
1934 }
1935
1936 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
1937 struct iov_iter *to,
1938 int noblock, struct sk_buff *skb)
1939 {
1940 ssize_t ret;
1941 int err;
1942
1943 tun_debug(KERN_INFO, tun, "tun_do_read\n");
1944
1945 if (!iov_iter_count(to))
1946 return 0;
1947
1948 if (!skb) {
1949 /* Read frames from ring */
1950 skb = tun_ring_recv(tfile, noblock, &err);
1951 if (!skb)
1952 return err;
1953 }
1954
1955 ret = tun_put_user(tun, tfile, skb, to);
1956 if (unlikely(ret < 0))
1957 kfree_skb(skb);
1958 else
1959 consume_skb(skb);
1960
1961 return ret;
1962 }
1963
1964 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
1965 {
1966 struct file *file = iocb->ki_filp;
1967 struct tun_file *tfile = file->private_data;
1968 struct tun_struct *tun = tun_get(tfile);
1969 ssize_t len = iov_iter_count(to), ret;
1970
1971 if (!tun)
1972 return -EBADFD;
1973 ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK, NULL);
1974 ret = min_t(ssize_t, ret, len);
1975 if (ret > 0)
1976 iocb->ki_pos = ret;
1977 tun_put(tun);
1978 return ret;
1979 }
1980
1981 static void tun_free_netdev(struct net_device *dev)
1982 {
1983 struct tun_struct *tun = netdev_priv(dev);
1984
1985 BUG_ON(!(list_empty(&tun->disabled)));
1986 free_percpu(tun->pcpu_stats);
1987 tun_flow_uninit(tun);
1988 security_tun_dev_free_security(tun->security);
1989 }
1990
1991 static void tun_setup(struct net_device *dev)
1992 {
1993 struct tun_struct *tun = netdev_priv(dev);
1994
1995 tun->owner = INVALID_UID;
1996 tun->group = INVALID_GID;
1997
1998 dev->ethtool_ops = &tun_ethtool_ops;
1999 dev->needs_free_netdev = true;
2000 dev->priv_destructor = tun_free_netdev;
2001 /* We prefer our own queue length */
2002 dev->tx_queue_len = TUN_READQ_SIZE;
2003 }
2004
2005 /* Trivial set of netlink ops to allow deleting tun or tap
2006 * device with netlink.
2007 */
2008 static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
2009 struct netlink_ext_ack *extack)
2010 {
2011 return -EINVAL;
2012 }
2013
2014 static struct rtnl_link_ops tun_link_ops __read_mostly = {
2015 .kind = DRV_NAME,
2016 .priv_size = sizeof(struct tun_struct),
2017 .setup = tun_setup,
2018 .validate = tun_validate,
2019 };
2020
2021 static void tun_sock_write_space(struct sock *sk)
2022 {
2023 struct tun_file *tfile;
2024 wait_queue_head_t *wqueue;
2025
2026 if (!sock_writeable(sk))
2027 return;
2028
2029 if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
2030 return;
2031
2032 wqueue = sk_sleep(sk);
2033 if (wqueue && waitqueue_active(wqueue))
2034 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
2035 POLLWRNORM | POLLWRBAND);
2036
2037 tfile = container_of(sk, struct tun_file, sk);
2038 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
2039 }
2040
2041 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
2042 {
2043 int ret;
2044 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2045 struct tun_struct *tun = tun_get(tfile);
2046
2047 if (!tun)
2048 return -EBADFD;
2049
2050 ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter,
2051 m->msg_flags & MSG_DONTWAIT,
2052 m->msg_flags & MSG_MORE);
2053 tun_put(tun);
2054 return ret;
2055 }
2056
2057 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
2058 int flags)
2059 {
2060 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2061 struct tun_struct *tun = tun_get(tfile);
2062 int ret;
2063
2064 if (!tun)
2065 return -EBADFD;
2066
2067 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
2068 ret = -EINVAL;
2069 goto out;
2070 }
2071 if (flags & MSG_ERRQUEUE) {
2072 ret = sock_recv_errqueue(sock->sk, m, total_len,
2073 SOL_PACKET, TUN_TX_TIMESTAMP);
2074 goto out;
2075 }
2076 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT,
2077 m->msg_control);
2078 if (ret > (ssize_t)total_len) {
2079 m->msg_flags |= MSG_TRUNC;
2080 ret = flags & MSG_TRUNC ? ret : total_len;
2081 }
2082 out:
2083 tun_put(tun);
2084 return ret;
2085 }
2086
2087 static int tun_peek_len(struct socket *sock)
2088 {
2089 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2090 struct tun_struct *tun;
2091 int ret = 0;
2092
2093 tun = tun_get(tfile);
2094 if (!tun)
2095 return 0;
2096
2097 ret = skb_array_peek_len(&tfile->tx_array);
2098 tun_put(tun);
2099
2100 return ret;
2101 }
2102
2103 /* Ops structure to mimic raw sockets with tun */
2104 static const struct proto_ops tun_socket_ops = {
2105 .peek_len = tun_peek_len,
2106 .sendmsg = tun_sendmsg,
2107 .recvmsg = tun_recvmsg,
2108 };
2109
2110 static struct proto tun_proto = {
2111 .name = "tun",
2112 .owner = THIS_MODULE,
2113 .obj_size = sizeof(struct tun_file),
2114 };
2115
2116 static int tun_flags(struct tun_struct *tun)
2117 {
2118 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
2119 }
2120
2121 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
2122 char *buf)
2123 {
2124 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2125 return sprintf(buf, "0x%x\n", tun_flags(tun));
2126 }
2127
2128 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
2129 char *buf)
2130 {
2131 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2132 return uid_valid(tun->owner)?
2133 sprintf(buf, "%u\n",
2134 from_kuid_munged(current_user_ns(), tun->owner)):
2135 sprintf(buf, "-1\n");
2136 }
2137
2138 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
2139 char *buf)
2140 {
2141 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2142 return gid_valid(tun->group) ?
2143 sprintf(buf, "%u\n",
2144 from_kgid_munged(current_user_ns(), tun->group)):
2145 sprintf(buf, "-1\n");
2146 }
2147
2148 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
2149 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
2150 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
2151
2152 static struct attribute *tun_dev_attrs[] = {
2153 &dev_attr_tun_flags.attr,
2154 &dev_attr_owner.attr,
2155 &dev_attr_group.attr,
2156 NULL
2157 };
2158
2159 static const struct attribute_group tun_attr_group = {
2160 .attrs = tun_dev_attrs
2161 };
2162
2163 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
2164 {
2165 struct tun_struct *tun;
2166 struct tun_file *tfile = file->private_data;
2167 struct net_device *dev;
2168 int err;
2169
2170 if (tfile->detached)
2171 return -EINVAL;
2172
2173 if ((ifr->ifr_flags & IFF_NAPI_FRAGS)) {
2174 if (!capable(CAP_NET_ADMIN))
2175 return -EPERM;
2176
2177 if (!(ifr->ifr_flags & IFF_NAPI) ||
2178 (ifr->ifr_flags & TUN_TYPE_MASK) != IFF_TAP)
2179 return -EINVAL;
2180 }
2181
2182 dev = __dev_get_by_name(net, ifr->ifr_name);
2183 if (dev) {
2184 if (ifr->ifr_flags & IFF_TUN_EXCL)
2185 return -EBUSY;
2186 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
2187 tun = netdev_priv(dev);
2188 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
2189 tun = netdev_priv(dev);
2190 else
2191 return -EINVAL;
2192
2193 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
2194 !!(tun->flags & IFF_MULTI_QUEUE))
2195 return -EINVAL;
2196
2197 if (tun_not_capable(tun))
2198 return -EPERM;
2199 err = security_tun_dev_open(tun->security);
2200 if (err < 0)
2201 return err;
2202
2203 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER,
2204 ifr->ifr_flags & IFF_NAPI);
2205 if (err < 0)
2206 return err;
2207
2208 if (tun->flags & IFF_MULTI_QUEUE &&
2209 (tun->numqueues + tun->numdisabled > 1)) {
2210 /* One or more queue has already been attached, no need
2211 * to initialize the device again.
2212 */
2213 return 0;
2214 }
2215 }
2216 else {
2217 char *name;
2218 unsigned long flags = 0;
2219 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
2220 MAX_TAP_QUEUES : 1;
2221
2222 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2223 return -EPERM;
2224 err = security_tun_dev_create();
2225 if (err < 0)
2226 return err;
2227
2228 /* Set dev type */
2229 if (ifr->ifr_flags & IFF_TUN) {
2230 /* TUN device */
2231 flags |= IFF_TUN;
2232 name = "tun%d";
2233 } else if (ifr->ifr_flags & IFF_TAP) {
2234 /* TAP device */
2235 flags |= IFF_TAP;
2236 name = "tap%d";
2237 } else
2238 return -EINVAL;
2239
2240 if (*ifr->ifr_name)
2241 name = ifr->ifr_name;
2242
2243 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
2244 NET_NAME_UNKNOWN, tun_setup, queues,
2245 queues);
2246
2247 if (!dev)
2248 return -ENOMEM;
2249
2250 dev_net_set(dev, net);
2251 dev->rtnl_link_ops = &tun_link_ops;
2252 dev->ifindex = tfile->ifindex;
2253 dev->sysfs_groups[0] = &tun_attr_group;
2254
2255 tun = netdev_priv(dev);
2256 tun->dev = dev;
2257 tun->flags = flags;
2258 tun->txflt.count = 0;
2259 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
2260
2261 tun->align = NET_SKB_PAD;
2262 tun->filter_attached = false;
2263 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
2264 tun->rx_batched = 0;
2265
2266 tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats);
2267 if (!tun->pcpu_stats) {
2268 err = -ENOMEM;
2269 goto err_free_dev;
2270 }
2271
2272 spin_lock_init(&tun->lock);
2273
2274 err = security_tun_dev_alloc_security(&tun->security);
2275 if (err < 0)
2276 goto err_free_stat;
2277
2278 tun_net_init(dev);
2279 tun_flow_init(tun);
2280
2281 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
2282 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
2283 NETIF_F_HW_VLAN_STAG_TX;
2284 dev->features = dev->hw_features | NETIF_F_LLTX;
2285 dev->vlan_features = dev->features &
2286 ~(NETIF_F_HW_VLAN_CTAG_TX |
2287 NETIF_F_HW_VLAN_STAG_TX);
2288
2289 INIT_LIST_HEAD(&tun->disabled);
2290 err = tun_attach(tun, file, false, ifr->ifr_flags & IFF_NAPI);
2291 if (err < 0)
2292 goto err_free_flow;
2293
2294 err = register_netdevice(tun->dev);
2295 if (err < 0)
2296 goto err_detach;
2297 }
2298
2299 netif_carrier_on(tun->dev);
2300
2301 tun_debug(KERN_INFO, tun, "tun_set_iff\n");
2302
2303 tun->flags = (tun->flags & ~TUN_FEATURES) |
2304 (ifr->ifr_flags & TUN_FEATURES);
2305
2306 /* Make sure persistent devices do not get stuck in
2307 * xoff state.
2308 */
2309 if (netif_running(tun->dev))
2310 netif_tx_wake_all_queues(tun->dev);
2311
2312 strcpy(ifr->ifr_name, tun->dev->name);
2313 return 0;
2314
2315 err_detach:
2316 tun_detach_all(dev);
2317 /* register_netdevice() already called tun_free_netdev() */
2318 goto err_free_dev;
2319
2320 err_free_flow:
2321 tun_flow_uninit(tun);
2322 security_tun_dev_free_security(tun->security);
2323 err_free_stat:
2324 free_percpu(tun->pcpu_stats);
2325 err_free_dev:
2326 free_netdev(dev);
2327 return err;
2328 }
2329
2330 static void tun_get_iff(struct net *net, struct tun_struct *tun,
2331 struct ifreq *ifr)
2332 {
2333 tun_debug(KERN_INFO, tun, "tun_get_iff\n");
2334
2335 strcpy(ifr->ifr_name, tun->dev->name);
2336
2337 ifr->ifr_flags = tun_flags(tun);
2338
2339 }
2340
2341 /* This is like a cut-down ethtool ops, except done via tun fd so no
2342 * privs required. */
2343 static int set_offload(struct tun_struct *tun, unsigned long arg)
2344 {
2345 netdev_features_t features = 0;
2346
2347 if (arg & TUN_F_CSUM) {
2348 features |= NETIF_F_HW_CSUM;
2349 arg &= ~TUN_F_CSUM;
2350
2351 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
2352 if (arg & TUN_F_TSO_ECN) {
2353 features |= NETIF_F_TSO_ECN;
2354 arg &= ~TUN_F_TSO_ECN;
2355 }
2356 if (arg & TUN_F_TSO4)
2357 features |= NETIF_F_TSO;
2358 if (arg & TUN_F_TSO6)
2359 features |= NETIF_F_TSO6;
2360 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
2361 }
2362 }
2363
2364 /* This gives the user a way to test for new features in future by
2365 * trying to set them. */
2366 if (arg)
2367 return -EINVAL;
2368
2369 tun->set_features = features;
2370 tun->dev->wanted_features &= ~TUN_USER_FEATURES;
2371 tun->dev->wanted_features |= features;
2372 netdev_update_features(tun->dev);
2373
2374 return 0;
2375 }
2376
2377 static void tun_detach_filter(struct tun_struct *tun, int n)
2378 {
2379 int i;
2380 struct tun_file *tfile;
2381
2382 for (i = 0; i < n; i++) {
2383 tfile = rtnl_dereference(tun->tfiles[i]);
2384 lock_sock(tfile->socket.sk);
2385 sk_detach_filter(tfile->socket.sk);
2386 release_sock(tfile->socket.sk);
2387 }
2388
2389 tun->filter_attached = false;
2390 }
2391
2392 static int tun_attach_filter(struct tun_struct *tun)
2393 {
2394 int i, ret = 0;
2395 struct tun_file *tfile;
2396
2397 for (i = 0; i < tun->numqueues; i++) {
2398 tfile = rtnl_dereference(tun->tfiles[i]);
2399 lock_sock(tfile->socket.sk);
2400 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
2401 release_sock(tfile->socket.sk);
2402 if (ret) {
2403 tun_detach_filter(tun, i);
2404 return ret;
2405 }
2406 }
2407
2408 tun->filter_attached = true;
2409 return ret;
2410 }
2411
2412 static void tun_set_sndbuf(struct tun_struct *tun)
2413 {
2414 struct tun_file *tfile;
2415 int i;
2416
2417 for (i = 0; i < tun->numqueues; i++) {
2418 tfile = rtnl_dereference(tun->tfiles[i]);
2419 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
2420 }
2421 }
2422
2423 static int tun_set_queue(struct file *file, struct ifreq *ifr)
2424 {
2425 struct tun_file *tfile = file->private_data;
2426 struct tun_struct *tun;
2427 int ret = 0;
2428
2429 rtnl_lock();
2430
2431 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
2432 tun = tfile->detached;
2433 if (!tun) {
2434 ret = -EINVAL;
2435 goto unlock;
2436 }
2437 ret = security_tun_dev_attach_queue(tun->security);
2438 if (ret < 0)
2439 goto unlock;
2440 ret = tun_attach(tun, file, false, tun->flags & IFF_NAPI);
2441 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
2442 tun = rtnl_dereference(tfile->tun);
2443 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
2444 ret = -EINVAL;
2445 else
2446 __tun_detach(tfile, false);
2447 } else
2448 ret = -EINVAL;
2449
2450 unlock:
2451 rtnl_unlock();
2452 return ret;
2453 }
2454
2455 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
2456 unsigned long arg, int ifreq_len)
2457 {
2458 struct tun_file *tfile = file->private_data;
2459 struct tun_struct *tun;
2460 void __user* argp = (void __user*)arg;
2461 struct ifreq ifr;
2462 kuid_t owner;
2463 kgid_t group;
2464 int sndbuf;
2465 int vnet_hdr_sz;
2466 unsigned int ifindex;
2467 int le;
2468 int ret;
2469
2470 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == SOCK_IOC_TYPE) {
2471 if (copy_from_user(&ifr, argp, ifreq_len))
2472 return -EFAULT;
2473 } else {
2474 memset(&ifr, 0, sizeof(ifr));
2475 }
2476 if (cmd == TUNGETFEATURES) {
2477 /* Currently this just means: "what IFF flags are valid?".
2478 * This is needed because we never checked for invalid flags on
2479 * TUNSETIFF.
2480 */
2481 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
2482 (unsigned int __user*)argp);
2483 } else if (cmd == TUNSETQUEUE)
2484 return tun_set_queue(file, &ifr);
2485
2486 ret = 0;
2487 rtnl_lock();
2488
2489 tun = tun_get(tfile);
2490 if (cmd == TUNSETIFF) {
2491 ret = -EEXIST;
2492 if (tun)
2493 goto unlock;
2494
2495 ifr.ifr_name[IFNAMSIZ-1] = '\0';
2496
2497 ret = tun_set_iff(sock_net(&tfile->sk), file, &ifr);
2498
2499 if (ret)
2500 goto unlock;
2501
2502 if (copy_to_user(argp, &ifr, ifreq_len))
2503 ret = -EFAULT;
2504 goto unlock;
2505 }
2506 if (cmd == TUNSETIFINDEX) {
2507 ret = -EPERM;
2508 if (tun)
2509 goto unlock;
2510
2511 ret = -EFAULT;
2512 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
2513 goto unlock;
2514
2515 ret = 0;
2516 tfile->ifindex = ifindex;
2517 goto unlock;
2518 }
2519
2520 ret = -EBADFD;
2521 if (!tun)
2522 goto unlock;
2523
2524 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
2525
2526 ret = 0;
2527 switch (cmd) {
2528 case TUNGETIFF:
2529 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2530
2531 if (tfile->detached)
2532 ifr.ifr_flags |= IFF_DETACH_QUEUE;
2533 if (!tfile->socket.sk->sk_filter)
2534 ifr.ifr_flags |= IFF_NOFILTER;
2535
2536 if (copy_to_user(argp, &ifr, ifreq_len))
2537 ret = -EFAULT;
2538 break;
2539
2540 case TUNSETNOCSUM:
2541 /* Disable/Enable checksum */
2542
2543 /* [unimplemented] */
2544 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
2545 arg ? "disabled" : "enabled");
2546 break;
2547
2548 case TUNSETPERSIST:
2549 /* Disable/Enable persist mode. Keep an extra reference to the
2550 * module to prevent the module being unprobed.
2551 */
2552 if (arg && !(tun->flags & IFF_PERSIST)) {
2553 tun->flags |= IFF_PERSIST;
2554 __module_get(THIS_MODULE);
2555 }
2556 if (!arg && (tun->flags & IFF_PERSIST)) {
2557 tun->flags &= ~IFF_PERSIST;
2558 module_put(THIS_MODULE);
2559 }
2560
2561 tun_debug(KERN_INFO, tun, "persist %s\n",
2562 arg ? "enabled" : "disabled");
2563 break;
2564
2565 case TUNSETOWNER:
2566 /* Set owner of the device */
2567 owner = make_kuid(current_user_ns(), arg);
2568 if (!uid_valid(owner)) {
2569 ret = -EINVAL;
2570 break;
2571 }
2572 tun->owner = owner;
2573 tun_debug(KERN_INFO, tun, "owner set to %u\n",
2574 from_kuid(&init_user_ns, tun->owner));
2575 break;
2576
2577 case TUNSETGROUP:
2578 /* Set group of the device */
2579 group = make_kgid(current_user_ns(), arg);
2580 if (!gid_valid(group)) {
2581 ret = -EINVAL;
2582 break;
2583 }
2584 tun->group = group;
2585 tun_debug(KERN_INFO, tun, "group set to %u\n",
2586 from_kgid(&init_user_ns, tun->group));
2587 break;
2588
2589 case TUNSETLINK:
2590 /* Only allow setting the type when the interface is down */
2591 if (tun->dev->flags & IFF_UP) {
2592 tun_debug(KERN_INFO, tun,
2593 "Linktype set failed because interface is up\n");
2594 ret = -EBUSY;
2595 } else {
2596 tun->dev->type = (int) arg;
2597 tun_debug(KERN_INFO, tun, "linktype set to %d\n",
2598 tun->dev->type);
2599 ret = 0;
2600 }
2601 break;
2602
2603 #ifdef TUN_DEBUG
2604 case TUNSETDEBUG:
2605 tun->debug = arg;
2606 break;
2607 #endif
2608 case TUNSETOFFLOAD:
2609 ret = set_offload(tun, arg);
2610 break;
2611
2612 case TUNSETTXFILTER:
2613 /* Can be set only for TAPs */
2614 ret = -EINVAL;
2615 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2616 break;
2617 ret = update_filter(&tun->txflt, (void __user *)arg);
2618 break;
2619
2620 case SIOCGIFHWADDR:
2621 /* Get hw address */
2622 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
2623 ifr.ifr_hwaddr.sa_family = tun->dev->type;
2624 if (copy_to_user(argp, &ifr, ifreq_len))
2625 ret = -EFAULT;
2626 break;
2627
2628 case SIOCSIFHWADDR:
2629 /* Set hw address */
2630 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
2631 ifr.ifr_hwaddr.sa_data);
2632
2633 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
2634 break;
2635
2636 case TUNGETSNDBUF:
2637 sndbuf = tfile->socket.sk->sk_sndbuf;
2638 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
2639 ret = -EFAULT;
2640 break;
2641
2642 case TUNSETSNDBUF:
2643 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
2644 ret = -EFAULT;
2645 break;
2646 }
2647
2648 tun->sndbuf = sndbuf;
2649 tun_set_sndbuf(tun);
2650 break;
2651
2652 case TUNGETVNETHDRSZ:
2653 vnet_hdr_sz = tun->vnet_hdr_sz;
2654 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
2655 ret = -EFAULT;
2656 break;
2657
2658 case TUNSETVNETHDRSZ:
2659 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
2660 ret = -EFAULT;
2661 break;
2662 }
2663 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
2664 ret = -EINVAL;
2665 break;
2666 }
2667
2668 tun->vnet_hdr_sz = vnet_hdr_sz;
2669 break;
2670
2671 case TUNGETVNETLE:
2672 le = !!(tun->flags & TUN_VNET_LE);
2673 if (put_user(le, (int __user *)argp))
2674 ret = -EFAULT;
2675 break;
2676
2677 case TUNSETVNETLE:
2678 if (get_user(le, (int __user *)argp)) {
2679 ret = -EFAULT;
2680 break;
2681 }
2682 if (le)
2683 tun->flags |= TUN_VNET_LE;
2684 else
2685 tun->flags &= ~TUN_VNET_LE;
2686 break;
2687
2688 case TUNGETVNETBE:
2689 ret = tun_get_vnet_be(tun, argp);
2690 break;
2691
2692 case TUNSETVNETBE:
2693 ret = tun_set_vnet_be(tun, argp);
2694 break;
2695
2696 case TUNATTACHFILTER:
2697 /* Can be set only for TAPs */
2698 ret = -EINVAL;
2699 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2700 break;
2701 ret = -EFAULT;
2702 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
2703 break;
2704
2705 ret = tun_attach_filter(tun);
2706 break;
2707
2708 case TUNDETACHFILTER:
2709 /* Can be set only for TAPs */
2710 ret = -EINVAL;
2711 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2712 break;
2713 ret = 0;
2714 tun_detach_filter(tun, tun->numqueues);
2715 break;
2716
2717 case TUNGETFILTER:
2718 ret = -EINVAL;
2719 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2720 break;
2721 ret = -EFAULT;
2722 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
2723 break;
2724 ret = 0;
2725 break;
2726
2727 default:
2728 ret = -EINVAL;
2729 break;
2730 }
2731
2732 unlock:
2733 rtnl_unlock();
2734 if (tun)
2735 tun_put(tun);
2736 return ret;
2737 }
2738
2739 static long tun_chr_ioctl(struct file *file,
2740 unsigned int cmd, unsigned long arg)
2741 {
2742 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
2743 }
2744
2745 #ifdef CONFIG_COMPAT
2746 static long tun_chr_compat_ioctl(struct file *file,
2747 unsigned int cmd, unsigned long arg)
2748 {
2749 switch (cmd) {
2750 case TUNSETIFF:
2751 case TUNGETIFF:
2752 case TUNSETTXFILTER:
2753 case TUNGETSNDBUF:
2754 case TUNSETSNDBUF:
2755 case SIOCGIFHWADDR:
2756 case SIOCSIFHWADDR:
2757 arg = (unsigned long)compat_ptr(arg);
2758 break;
2759 default:
2760 arg = (compat_ulong_t)arg;
2761 break;
2762 }
2763
2764 /*
2765 * compat_ifreq is shorter than ifreq, so we must not access beyond
2766 * the end of that structure. All fields that are used in this
2767 * driver are compatible though, we don't need to convert the
2768 * contents.
2769 */
2770 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
2771 }
2772 #endif /* CONFIG_COMPAT */
2773
2774 static int tun_chr_fasync(int fd, struct file *file, int on)
2775 {
2776 struct tun_file *tfile = file->private_data;
2777 int ret;
2778
2779 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
2780 goto out;
2781
2782 if (on) {
2783 __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
2784 tfile->flags |= TUN_FASYNC;
2785 } else
2786 tfile->flags &= ~TUN_FASYNC;
2787 ret = 0;
2788 out:
2789 return ret;
2790 }
2791
2792 static int tun_chr_open(struct inode *inode, struct file * file)
2793 {
2794 struct net *net = current->nsproxy->net_ns;
2795 struct tun_file *tfile;
2796
2797 DBG1(KERN_INFO, "tunX: tun_chr_open\n");
2798
2799 tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
2800 &tun_proto, 0);
2801 if (!tfile)
2802 return -ENOMEM;
2803 RCU_INIT_POINTER(tfile->tun, NULL);
2804 tfile->flags = 0;
2805 tfile->ifindex = 0;
2806
2807 init_waitqueue_head(&tfile->wq.wait);
2808 RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq);
2809
2810 tfile->socket.file = file;
2811 tfile->socket.ops = &tun_socket_ops;
2812
2813 sock_init_data(&tfile->socket, &tfile->sk);
2814
2815 tfile->sk.sk_write_space = tun_sock_write_space;
2816 tfile->sk.sk_sndbuf = INT_MAX;
2817
2818 file->private_data = tfile;
2819 INIT_LIST_HEAD(&tfile->next);
2820
2821 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
2822
2823 return 0;
2824 }
2825
2826 static int tun_chr_close(struct inode *inode, struct file *file)
2827 {
2828 struct tun_file *tfile = file->private_data;
2829
2830 tun_detach(tfile, true);
2831
2832 return 0;
2833 }
2834
2835 #ifdef CONFIG_PROC_FS
2836 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *file)
2837 {
2838 struct tun_file *tfile = file->private_data;
2839 struct tun_struct *tun;
2840 struct ifreq ifr;
2841
2842 memset(&ifr, 0, sizeof(ifr));
2843
2844 rtnl_lock();
2845 tun = tun_get(tfile);
2846 if (tun)
2847 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2848 rtnl_unlock();
2849
2850 if (tun)
2851 tun_put(tun);
2852
2853 seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
2854 }
2855 #endif
2856
2857 static const struct file_operations tun_fops = {
2858 .owner = THIS_MODULE,
2859 .llseek = no_llseek,
2860 .read_iter = tun_chr_read_iter,
2861 .write_iter = tun_chr_write_iter,
2862 .poll = tun_chr_poll,
2863 .unlocked_ioctl = tun_chr_ioctl,
2864 #ifdef CONFIG_COMPAT
2865 .compat_ioctl = tun_chr_compat_ioctl,
2866 #endif
2867 .open = tun_chr_open,
2868 .release = tun_chr_close,
2869 .fasync = tun_chr_fasync,
2870 #ifdef CONFIG_PROC_FS
2871 .show_fdinfo = tun_chr_show_fdinfo,
2872 #endif
2873 };
2874
2875 static struct miscdevice tun_miscdev = {
2876 .minor = TUN_MINOR,
2877 .name = "tun",
2878 .nodename = "net/tun",
2879 .fops = &tun_fops,
2880 };
2881
2882 /* ethtool interface */
2883
2884 static int tun_get_link_ksettings(struct net_device *dev,
2885 struct ethtool_link_ksettings *cmd)
2886 {
2887 ethtool_link_ksettings_zero_link_mode(cmd, supported);
2888 ethtool_link_ksettings_zero_link_mode(cmd, advertising);
2889 cmd->base.speed = SPEED_10;
2890 cmd->base.duplex = DUPLEX_FULL;
2891 cmd->base.port = PORT_TP;
2892 cmd->base.phy_address = 0;
2893 cmd->base.autoneg = AUTONEG_DISABLE;
2894 return 0;
2895 }
2896
2897 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
2898 {
2899 struct tun_struct *tun = netdev_priv(dev);
2900
2901 strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
2902 strlcpy(info->version, DRV_VERSION, sizeof(info->version));
2903
2904 switch (tun->flags & TUN_TYPE_MASK) {
2905 case IFF_TUN:
2906 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
2907 break;
2908 case IFF_TAP:
2909 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
2910 break;
2911 }
2912 }
2913
2914 static u32 tun_get_msglevel(struct net_device *dev)
2915 {
2916 #ifdef TUN_DEBUG
2917 struct tun_struct *tun = netdev_priv(dev);
2918 return tun->debug;
2919 #else
2920 return -EOPNOTSUPP;
2921 #endif
2922 }
2923
2924 static void tun_set_msglevel(struct net_device *dev, u32 value)
2925 {
2926 #ifdef TUN_DEBUG
2927 struct tun_struct *tun = netdev_priv(dev);
2928 tun->debug = value;
2929 #endif
2930 }
2931
2932 static int tun_get_coalesce(struct net_device *dev,
2933 struct ethtool_coalesce *ec)
2934 {
2935 struct tun_struct *tun = netdev_priv(dev);
2936
2937 ec->rx_max_coalesced_frames = tun->rx_batched;
2938
2939 return 0;
2940 }
2941
2942 static int tun_set_coalesce(struct net_device *dev,
2943 struct ethtool_coalesce *ec)
2944 {
2945 struct tun_struct *tun = netdev_priv(dev);
2946
2947 if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT)
2948 tun->rx_batched = NAPI_POLL_WEIGHT;
2949 else
2950 tun->rx_batched = ec->rx_max_coalesced_frames;
2951
2952 return 0;
2953 }
2954
2955 static const struct ethtool_ops tun_ethtool_ops = {
2956 .get_drvinfo = tun_get_drvinfo,
2957 .get_msglevel = tun_get_msglevel,
2958 .set_msglevel = tun_set_msglevel,
2959 .get_link = ethtool_op_get_link,
2960 .get_ts_info = ethtool_op_get_ts_info,
2961 .get_coalesce = tun_get_coalesce,
2962 .set_coalesce = tun_set_coalesce,
2963 .get_link_ksettings = tun_get_link_ksettings,
2964 };
2965
2966 static int tun_queue_resize(struct tun_struct *tun)
2967 {
2968 struct net_device *dev = tun->dev;
2969 struct tun_file *tfile;
2970 struct skb_array **arrays;
2971 int n = tun->numqueues + tun->numdisabled;
2972 int ret, i;
2973
2974 arrays = kmalloc_array(n, sizeof(*arrays), GFP_KERNEL);
2975 if (!arrays)
2976 return -ENOMEM;
2977
2978 for (i = 0; i < tun->numqueues; i++) {
2979 tfile = rtnl_dereference(tun->tfiles[i]);
2980 arrays[i] = &tfile->tx_array;
2981 }
2982 list_for_each_entry(tfile, &tun->disabled, next)
2983 arrays[i++] = &tfile->tx_array;
2984
2985 ret = skb_array_resize_multiple(arrays, n,
2986 dev->tx_queue_len, GFP_KERNEL);
2987
2988 kfree(arrays);
2989 return ret;
2990 }
2991
2992 static int tun_device_event(struct notifier_block *unused,
2993 unsigned long event, void *ptr)
2994 {
2995 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
2996 struct tun_struct *tun = netdev_priv(dev);
2997
2998 if (dev->rtnl_link_ops != &tun_link_ops)
2999 return NOTIFY_DONE;
3000
3001 switch (event) {
3002 case NETDEV_CHANGE_TX_QUEUE_LEN:
3003 if (tun_queue_resize(tun))
3004 return NOTIFY_BAD;
3005 break;
3006 default:
3007 break;
3008 }
3009
3010 return NOTIFY_DONE;
3011 }
3012
3013 static struct notifier_block tun_notifier_block __read_mostly = {
3014 .notifier_call = tun_device_event,
3015 };
3016
3017 static int __init tun_init(void)
3018 {
3019 int ret = 0;
3020
3021 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
3022
3023 ret = rtnl_link_register(&tun_link_ops);
3024 if (ret) {
3025 pr_err("Can't register link_ops\n");
3026 goto err_linkops;
3027 }
3028
3029 ret = misc_register(&tun_miscdev);
3030 if (ret) {
3031 pr_err("Can't register misc device %d\n", TUN_MINOR);
3032 goto err_misc;
3033 }
3034
3035 ret = register_netdevice_notifier(&tun_notifier_block);
3036 if (ret) {
3037 pr_err("Can't register netdevice notifier\n");
3038 goto err_notifier;
3039 }
3040
3041 return 0;
3042
3043 err_notifier:
3044 misc_deregister(&tun_miscdev);
3045 err_misc:
3046 rtnl_link_unregister(&tun_link_ops);
3047 err_linkops:
3048 return ret;
3049 }
3050
3051 static void tun_cleanup(void)
3052 {
3053 misc_deregister(&tun_miscdev);
3054 rtnl_link_unregister(&tun_link_ops);
3055 unregister_netdevice_notifier(&tun_notifier_block);
3056 }
3057
3058 /* Get an underlying socket object from tun file. Returns error unless file is
3059 * attached to a device. The returned object works like a packet socket, it
3060 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
3061 * holding a reference to the file for as long as the socket is in use. */
3062 struct socket *tun_get_socket(struct file *file)
3063 {
3064 struct tun_file *tfile;
3065 if (file->f_op != &tun_fops)
3066 return ERR_PTR(-EINVAL);
3067 tfile = file->private_data;
3068 if (!tfile)
3069 return ERR_PTR(-EBADFD);
3070 return &tfile->socket;
3071 }
3072 EXPORT_SYMBOL_GPL(tun_get_socket);
3073
3074 struct skb_array *tun_get_skb_array(struct file *file)
3075 {
3076 struct tun_file *tfile;
3077
3078 if (file->f_op != &tun_fops)
3079 return ERR_PTR(-EINVAL);
3080 tfile = file->private_data;
3081 if (!tfile)
3082 return ERR_PTR(-EBADFD);
3083 return &tfile->tx_array;
3084 }
3085 EXPORT_SYMBOL_GPL(tun_get_skb_array);
3086
3087 module_init(tun_init);
3088 module_exit(tun_cleanup);
3089 MODULE_DESCRIPTION(DRV_DESCRIPTION);
3090 MODULE_AUTHOR(DRV_COPYRIGHT);
3091 MODULE_LICENSE("GPL");
3092 MODULE_ALIAS_MISCDEV(TUN_MINOR);
3093 MODULE_ALIAS("devname:net/tun");
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