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mm/hmm.c: remove superfluous RCU protection around radix tree lookup
[linux/fpc-iii.git] / drivers / net / tun.c
bloba1ba262f40ad0755d2cea34867851bb7acd8e2de
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 #include <linux/proc_fs.h>
82
83 /* Uncomment to enable debugging */
84 /* #define TUN_DEBUG 1 */
85
86 #ifdef TUN_DEBUG
87 static int debug;
88
89 #define tun_debug(level, tun, fmt, args...) \
90 do { \
91 if (tun->debug) \
92 netdev_printk(level, tun->dev, fmt, ##args); \
93 } while (0)
94 #define DBG1(level, fmt, args...) \
95 do { \
96 if (debug == 2) \
97 printk(level fmt, ##args); \
98 } while (0)
99 #else
100 #define tun_debug(level, tun, fmt, args...) \
101 do { \
102 if (0) \
103 netdev_printk(level, tun->dev, fmt, ##args); \
104 } while (0)
105 #define DBG1(level, fmt, args...) \
106 do { \
107 if (0) \
108 printk(level fmt, ##args); \
109 } while (0)
110 #endif
111
112 #define TUN_HEADROOM 256
113 #define TUN_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
114
115 /* TUN device flags */
116
117 /* IFF_ATTACH_QUEUE is never stored in device flags,
118 * overload it to mean fasync when stored there.
119 */
120 #define TUN_FASYNC IFF_ATTACH_QUEUE
121 /* High bits in flags field are unused. */
122 #define TUN_VNET_LE 0x80000000
123 #define TUN_VNET_BE 0x40000000
124
125 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
126 IFF_MULTI_QUEUE | IFF_NAPI | IFF_NAPI_FRAGS)
127
128 #define GOODCOPY_LEN 128
129
130 #define FLT_EXACT_COUNT 8
131 struct tap_filter {
132 unsigned int count; /* Number of addrs. Zero means disabled */
133 u32 mask[2]; /* Mask of the hashed addrs */
134 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
135 };
136
137 /* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
138 * to max number of VCPUs in guest. */
139 #define MAX_TAP_QUEUES 256
140 #define MAX_TAP_FLOWS 4096
141
142 #define TUN_FLOW_EXPIRE (3 * HZ)
143
144 struct tun_pcpu_stats {
145 u64 rx_packets;
146 u64 rx_bytes;
147 u64 tx_packets;
148 u64 tx_bytes;
149 struct u64_stats_sync syncp;
150 u32 rx_dropped;
151 u32 tx_dropped;
152 u32 rx_frame_errors;
153 };
154
155 /* A tun_file connects an open character device to a tuntap netdevice. It
156 * also contains all socket related structures (except sock_fprog and tap_filter)
157 * to serve as one transmit queue for tuntap device. The sock_fprog and
158 * tap_filter were kept in tun_struct since they were used for filtering for the
159 * netdevice not for a specific queue (at least I didn't see the requirement for
160 * this).
161 *
162 * RCU usage:
163 * The tun_file and tun_struct are loosely coupled, the pointer from one to the
164 * other can only be read while rcu_read_lock or rtnl_lock is held.
165 */
166 struct tun_file {
167 struct sock sk;
168 struct socket socket;
169 struct socket_wq wq;
170 struct tun_struct __rcu *tun;
171 struct fasync_struct *fasync;
172 /* only used for fasnyc */
173 unsigned int flags;
174 union {
175 u16 queue_index;
176 unsigned int ifindex;
177 };
178 struct napi_struct napi;
179 bool napi_enabled;
180 struct mutex napi_mutex; /* Protects access to the above napi */
181 struct list_head next;
182 struct tun_struct *detached;
183 struct ptr_ring tx_ring;
184 struct xdp_rxq_info xdp_rxq;
185 };
186
187 struct tun_flow_entry {
188 struct hlist_node hash_link;
189 struct rcu_head rcu;
190 struct tun_struct *tun;
191
192 u32 rxhash;
193 u32 rps_rxhash;
194 int queue_index;
195 unsigned long updated;
196 };
197
198 #define TUN_NUM_FLOW_ENTRIES 1024
199
200 struct tun_prog {
201 struct rcu_head rcu;
202 struct bpf_prog *prog;
203 };
204
205 /* Since the socket were moved to tun_file, to preserve the behavior of persist
206 * device, socket filter, sndbuf and vnet header size were restore when the
207 * file were attached to a persist device.
208 */
209 struct tun_struct {
210 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES];
211 unsigned int numqueues;
212 unsigned int flags;
213 kuid_t owner;
214 kgid_t group;
215
216 struct net_device *dev;
217 netdev_features_t set_features;
218 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
219 NETIF_F_TSO6)
220
221 int align;
222 int vnet_hdr_sz;
223 int sndbuf;
224 struct tap_filter txflt;
225 struct sock_fprog fprog;
226 /* protected by rtnl lock */
227 bool filter_attached;
228 #ifdef TUN_DEBUG
229 int debug;
230 #endif
231 spinlock_t lock;
232 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
233 struct timer_list flow_gc_timer;
234 unsigned long ageing_time;
235 unsigned int numdisabled;
236 struct list_head disabled;
237 void *security;
238 u32 flow_count;
239 u32 rx_batched;
240 struct tun_pcpu_stats __percpu *pcpu_stats;
241 struct bpf_prog __rcu *xdp_prog;
242 struct tun_prog __rcu *steering_prog;
243 struct tun_prog __rcu *filter_prog;
244 };
245
246 struct veth {
247 __be16 h_vlan_proto;
248 __be16 h_vlan_TCI;
249 };
250
251 bool tun_is_xdp_buff(void *ptr)
252 {
253 return (unsigned long)ptr & TUN_XDP_FLAG;
254 }
255 EXPORT_SYMBOL(tun_is_xdp_buff);
256
257 void *tun_xdp_to_ptr(void *ptr)
258 {
259 return (void *)((unsigned long)ptr | TUN_XDP_FLAG);
260 }
261 EXPORT_SYMBOL(tun_xdp_to_ptr);
262
263 void *tun_ptr_to_xdp(void *ptr)
264 {
265 return (void *)((unsigned long)ptr & ~TUN_XDP_FLAG);
266 }
267 EXPORT_SYMBOL(tun_ptr_to_xdp);
268
269 static int tun_napi_receive(struct napi_struct *napi, int budget)
270 {
271 struct tun_file *tfile = container_of(napi, struct tun_file, napi);
272 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
273 struct sk_buff_head process_queue;
274 struct sk_buff *skb;
275 int received = 0;
276
277 __skb_queue_head_init(&process_queue);
278
279 spin_lock(&queue->lock);
280 skb_queue_splice_tail_init(queue, &process_queue);
281 spin_unlock(&queue->lock);
282
283 while (received < budget && (skb = __skb_dequeue(&process_queue))) {
284 napi_gro_receive(napi, skb);
285 ++received;
286 }
287
288 if (!skb_queue_empty(&process_queue)) {
289 spin_lock(&queue->lock);
290 skb_queue_splice(&process_queue, queue);
291 spin_unlock(&queue->lock);
292 }
293
294 return received;
295 }
296
297 static int tun_napi_poll(struct napi_struct *napi, int budget)
298 {
299 unsigned int received;
300
301 received = tun_napi_receive(napi, budget);
302
303 if (received < budget)
304 napi_complete_done(napi, received);
305
306 return received;
307 }
308
309 static void tun_napi_init(struct tun_struct *tun, struct tun_file *tfile,
310 bool napi_en)
311 {
312 tfile->napi_enabled = napi_en;
313 if (napi_en) {
314 netif_napi_add(tun->dev, &tfile->napi, tun_napi_poll,
315 NAPI_POLL_WEIGHT);
316 napi_enable(&tfile->napi);
317 mutex_init(&tfile->napi_mutex);
318 }
319 }
320
321 static void tun_napi_disable(struct tun_struct *tun, struct tun_file *tfile)
322 {
323 if (tfile->napi_enabled)
324 napi_disable(&tfile->napi);
325 }
326
327 static void tun_napi_del(struct tun_struct *tun, struct tun_file *tfile)
328 {
329 if (tfile->napi_enabled)
330 netif_napi_del(&tfile->napi);
331 }
332
333 static bool tun_napi_frags_enabled(const struct tun_struct *tun)
334 {
335 return READ_ONCE(tun->flags) & IFF_NAPI_FRAGS;
336 }
337
338 #ifdef CONFIG_TUN_VNET_CROSS_LE
339 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
340 {
341 return tun->flags & TUN_VNET_BE ? false :
342 virtio_legacy_is_little_endian();
343 }
344
345 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
346 {
347 int be = !!(tun->flags & TUN_VNET_BE);
348
349 if (put_user(be, argp))
350 return -EFAULT;
351
352 return 0;
353 }
354
355 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
356 {
357 int be;
358
359 if (get_user(be, argp))
360 return -EFAULT;
361
362 if (be)
363 tun->flags |= TUN_VNET_BE;
364 else
365 tun->flags &= ~TUN_VNET_BE;
366
367 return 0;
368 }
369 #else
370 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
371 {
372 return virtio_legacy_is_little_endian();
373 }
374
375 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
376 {
377 return -EINVAL;
378 }
379
380 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
381 {
382 return -EINVAL;
383 }
384 #endif /* CONFIG_TUN_VNET_CROSS_LE */
385
386 static inline bool tun_is_little_endian(struct tun_struct *tun)
387 {
388 return tun->flags & TUN_VNET_LE ||
389 tun_legacy_is_little_endian(tun);
390 }
391
392 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
393 {
394 return __virtio16_to_cpu(tun_is_little_endian(tun), val);
395 }
396
397 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
398 {
399 return __cpu_to_virtio16(tun_is_little_endian(tun), val);
400 }
401
402 static inline u32 tun_hashfn(u32 rxhash)
403 {
404 return rxhash & 0x3ff;
405 }
406
407 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
408 {
409 struct tun_flow_entry *e;
410
411 hlist_for_each_entry_rcu(e, head, hash_link) {
412 if (e->rxhash == rxhash)
413 return e;
414 }
415 return NULL;
416 }
417
418 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
419 struct hlist_head *head,
420 u32 rxhash, u16 queue_index)
421 {
422 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
423
424 if (e) {
425 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
426 rxhash, queue_index);
427 e->updated = jiffies;
428 e->rxhash = rxhash;
429 e->rps_rxhash = 0;
430 e->queue_index = queue_index;
431 e->tun = tun;
432 hlist_add_head_rcu(&e->hash_link, head);
433 ++tun->flow_count;
434 }
435 return e;
436 }
437
438 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
439 {
440 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
441 e->rxhash, e->queue_index);
442 hlist_del_rcu(&e->hash_link);
443 kfree_rcu(e, rcu);
444 --tun->flow_count;
445 }
446
447 static void tun_flow_flush(struct tun_struct *tun)
448 {
449 int i;
450
451 spin_lock_bh(&tun->lock);
452 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
453 struct tun_flow_entry *e;
454 struct hlist_node *n;
455
456 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
457 tun_flow_delete(tun, e);
458 }
459 spin_unlock_bh(&tun->lock);
460 }
461
462 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
463 {
464 int i;
465
466 spin_lock_bh(&tun->lock);
467 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
468 struct tun_flow_entry *e;
469 struct hlist_node *n;
470
471 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
472 if (e->queue_index == queue_index)
473 tun_flow_delete(tun, e);
474 }
475 }
476 spin_unlock_bh(&tun->lock);
477 }
478
479 static void tun_flow_cleanup(struct timer_list *t)
480 {
481 struct tun_struct *tun = from_timer(tun, t, flow_gc_timer);
482 unsigned long delay = tun->ageing_time;
483 unsigned long next_timer = jiffies + delay;
484 unsigned long count = 0;
485 int i;
486
487 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
488
489 spin_lock(&tun->lock);
490 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
491 struct tun_flow_entry *e;
492 struct hlist_node *n;
493
494 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
495 unsigned long this_timer;
496
497 this_timer = e->updated + delay;
498 if (time_before_eq(this_timer, jiffies)) {
499 tun_flow_delete(tun, e);
500 continue;
501 }
502 count++;
503 if (time_before(this_timer, next_timer))
504 next_timer = this_timer;
505 }
506 }
507
508 if (count)
509 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
510 spin_unlock(&tun->lock);
511 }
512
513 static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
514 struct tun_file *tfile)
515 {
516 struct hlist_head *head;
517 struct tun_flow_entry *e;
518 unsigned long delay = tun->ageing_time;
519 u16 queue_index = tfile->queue_index;
520
521 if (!rxhash)
522 return;
523 else
524 head = &tun->flows[tun_hashfn(rxhash)];
525
526 rcu_read_lock();
527
528 /* We may get a very small possibility of OOO during switching, not
529 * worth to optimize.*/
530 if (tun->numqueues == 1 || tfile->detached)
531 goto unlock;
532
533 e = tun_flow_find(head, rxhash);
534 if (likely(e)) {
535 /* TODO: keep queueing to old queue until it's empty? */
536 e->queue_index = queue_index;
537 e->updated = jiffies;
538 sock_rps_record_flow_hash(e->rps_rxhash);
539 } else {
540 spin_lock_bh(&tun->lock);
541 if (!tun_flow_find(head, rxhash) &&
542 tun->flow_count < MAX_TAP_FLOWS)
543 tun_flow_create(tun, head, rxhash, queue_index);
544
545 if (!timer_pending(&tun->flow_gc_timer))
546 mod_timer(&tun->flow_gc_timer,
547 round_jiffies_up(jiffies + delay));
548 spin_unlock_bh(&tun->lock);
549 }
550
551 unlock:
552 rcu_read_unlock();
553 }
554
555 /**
556 * Save the hash received in the stack receive path and update the
557 * flow_hash table accordingly.
558 */
559 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
560 {
561 if (unlikely(e->rps_rxhash != hash))
562 e->rps_rxhash = hash;
563 }
564
565 /* We try to identify a flow through its rxhash first. The reason that
566 * we do not check rxq no. is because some cards(e.g 82599), chooses
567 * the rxq based on the txq where the last packet of the flow comes. As
568 * the userspace application move between processors, we may get a
569 * different rxq no. here. If we could not get rxhash, then we would
570 * hope the rxq no. may help here.
571 */
572 static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb)
573 {
574 struct tun_flow_entry *e;
575 u32 txq = 0;
576 u32 numqueues = 0;
577
578 numqueues = READ_ONCE(tun->numqueues);
579
580 txq = __skb_get_hash_symmetric(skb);
581 if (txq) {
582 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
583 if (e) {
584 tun_flow_save_rps_rxhash(e, txq);
585 txq = e->queue_index;
586 } else
587 /* use multiply and shift instead of expensive divide */
588 txq = ((u64)txq * numqueues) >> 32;
589 } else if (likely(skb_rx_queue_recorded(skb))) {
590 txq = skb_get_rx_queue(skb);
591 while (unlikely(txq >= numqueues))
592 txq -= numqueues;
593 }
594
595 return txq;
596 }
597
598 static u16 tun_ebpf_select_queue(struct tun_struct *tun, struct sk_buff *skb)
599 {
600 struct tun_prog *prog;
601 u16 ret = 0;
602
603 prog = rcu_dereference(tun->steering_prog);
604 if (prog)
605 ret = bpf_prog_run_clear_cb(prog->prog, skb);
606
607 return ret % tun->numqueues;
608 }
609
610 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
611 void *accel_priv, select_queue_fallback_t fallback)
612 {
613 struct tun_struct *tun = netdev_priv(dev);
614 u16 ret;
615
616 rcu_read_lock();
617 if (rcu_dereference(tun->steering_prog))
618 ret = tun_ebpf_select_queue(tun, skb);
619 else
620 ret = tun_automq_select_queue(tun, skb);
621 rcu_read_unlock();
622
623 return ret;
624 }
625
626 static inline bool tun_not_capable(struct tun_struct *tun)
627 {
628 const struct cred *cred = current_cred();
629 struct net *net = dev_net(tun->dev);
630
631 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
632 (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
633 !ns_capable(net->user_ns, CAP_NET_ADMIN);
634 }
635
636 static void tun_set_real_num_queues(struct tun_struct *tun)
637 {
638 netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
639 netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
640 }
641
642 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
643 {
644 tfile->detached = tun;
645 list_add_tail(&tfile->next, &tun->disabled);
646 ++tun->numdisabled;
647 }
648
649 static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
650 {
651 struct tun_struct *tun = tfile->detached;
652
653 tfile->detached = NULL;
654 list_del_init(&tfile->next);
655 --tun->numdisabled;
656 return tun;
657 }
658
659 void tun_ptr_free(void *ptr)
660 {
661 if (!ptr)
662 return;
663 if (tun_is_xdp_buff(ptr)) {
664 struct xdp_buff *xdp = tun_ptr_to_xdp(ptr);
665
666 put_page(virt_to_head_page(xdp->data));
667 } else {
668 __skb_array_destroy_skb(ptr);
669 }
670 }
671 EXPORT_SYMBOL_GPL(tun_ptr_free);
672
673 static void tun_queue_purge(struct tun_file *tfile)
674 {
675 void *ptr;
676
677 while ((ptr = ptr_ring_consume(&tfile->tx_ring)) != NULL)
678 tun_ptr_free(ptr);
679
680 skb_queue_purge(&tfile->sk.sk_write_queue);
681 skb_queue_purge(&tfile->sk.sk_error_queue);
682 }
683
684 static void tun_cleanup_tx_ring(struct tun_file *tfile)
685 {
686 if (tfile->tx_ring.queue) {
687 ptr_ring_cleanup(&tfile->tx_ring, tun_ptr_free);
688 xdp_rxq_info_unreg(&tfile->xdp_rxq);
689 memset(&tfile->tx_ring, 0, sizeof(tfile->tx_ring));
690 }
691 }
692
693 static void __tun_detach(struct tun_file *tfile, bool clean)
694 {
695 struct tun_file *ntfile;
696 struct tun_struct *tun;
697
698 tun = rtnl_dereference(tfile->tun);
699
700 if (tun && clean) {
701 tun_napi_disable(tun, tfile);
702 tun_napi_del(tun, tfile);
703 }
704
705 if (tun && !tfile->detached) {
706 u16 index = tfile->queue_index;
707 BUG_ON(index >= tun->numqueues);
708
709 rcu_assign_pointer(tun->tfiles[index],
710 tun->tfiles[tun->numqueues - 1]);
711 ntfile = rtnl_dereference(tun->tfiles[index]);
712 ntfile->queue_index = index;
713
714 --tun->numqueues;
715 if (clean) {
716 RCU_INIT_POINTER(tfile->tun, NULL);
717 sock_put(&tfile->sk);
718 } else
719 tun_disable_queue(tun, tfile);
720
721 synchronize_net();
722 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
723 /* Drop read queue */
724 tun_queue_purge(tfile);
725 tun_set_real_num_queues(tun);
726 } else if (tfile->detached && clean) {
727 tun = tun_enable_queue(tfile);
728 sock_put(&tfile->sk);
729 }
730
731 if (clean) {
732 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
733 netif_carrier_off(tun->dev);
734
735 if (!(tun->flags & IFF_PERSIST) &&
736 tun->dev->reg_state == NETREG_REGISTERED)
737 unregister_netdevice(tun->dev);
738 }
739 tun_cleanup_tx_ring(tfile);
740 sock_put(&tfile->sk);
741 }
742 }
743
744 static void tun_detach(struct tun_file *tfile, bool clean)
745 {
746 rtnl_lock();
747 __tun_detach(tfile, clean);
748 rtnl_unlock();
749 }
750
751 static void tun_detach_all(struct net_device *dev)
752 {
753 struct tun_struct *tun = netdev_priv(dev);
754 struct tun_file *tfile, *tmp;
755 int i, n = tun->numqueues;
756
757 for (i = 0; i < n; i++) {
758 tfile = rtnl_dereference(tun->tfiles[i]);
759 BUG_ON(!tfile);
760 tun_napi_disable(tun, tfile);
761 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
762 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
763 RCU_INIT_POINTER(tfile->tun, NULL);
764 --tun->numqueues;
765 }
766 list_for_each_entry(tfile, &tun->disabled, next) {
767 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
768 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
769 RCU_INIT_POINTER(tfile->tun, NULL);
770 }
771 BUG_ON(tun->numqueues != 0);
772
773 synchronize_net();
774 for (i = 0; i < n; i++) {
775 tfile = rtnl_dereference(tun->tfiles[i]);
776 tun_napi_del(tun, tfile);
777 /* Drop read queue */
778 tun_queue_purge(tfile);
779 sock_put(&tfile->sk);
780 tun_cleanup_tx_ring(tfile);
781 }
782 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
783 tun_enable_queue(tfile);
784 tun_queue_purge(tfile);
785 sock_put(&tfile->sk);
786 tun_cleanup_tx_ring(tfile);
787 }
788 BUG_ON(tun->numdisabled != 0);
789
790 if (tun->flags & IFF_PERSIST)
791 module_put(THIS_MODULE);
792 }
793
794 static int tun_attach(struct tun_struct *tun, struct file *file,
795 bool skip_filter, bool napi)
796 {
797 struct tun_file *tfile = file->private_data;
798 struct net_device *dev = tun->dev;
799 int err;
800
801 err = security_tun_dev_attach(tfile->socket.sk, tun->security);
802 if (err < 0)
803 goto out;
804
805 err = -EINVAL;
806 if (rtnl_dereference(tfile->tun) && !tfile->detached)
807 goto out;
808
809 err = -EBUSY;
810 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
811 goto out;
812
813 err = -E2BIG;
814 if (!tfile->detached &&
815 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
816 goto out;
817
818 err = 0;
819
820 /* Re-attach the filter to persist device */
821 if (!skip_filter && (tun->filter_attached == true)) {
822 lock_sock(tfile->socket.sk);
823 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
824 release_sock(tfile->socket.sk);
825 if (!err)
826 goto out;
827 }
828
829 if (!tfile->detached &&
830 ptr_ring_init(&tfile->tx_ring, dev->tx_queue_len, GFP_KERNEL)) {
831 err = -ENOMEM;
832 goto out;
833 }
834
835 tfile->queue_index = tun->numqueues;
836 tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
837
838 if (tfile->detached) {
839 /* Re-attach detached tfile, updating XDP queue_index */
840 WARN_ON(!xdp_rxq_info_is_reg(&tfile->xdp_rxq));
841
842 if (tfile->xdp_rxq.queue_index != tfile->queue_index)
843 tfile->xdp_rxq.queue_index = tfile->queue_index;
844 } else {
845 /* Setup XDP RX-queue info, for new tfile getting attached */
846 err = xdp_rxq_info_reg(&tfile->xdp_rxq,
847 tun->dev, tfile->queue_index);
848 if (err < 0)
849 goto out;
850 err = 0;
851 }
852
853 rcu_assign_pointer(tfile->tun, tun);
854 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
855 tun->numqueues++;
856
857 if (tfile->detached) {
858 tun_enable_queue(tfile);
859 } else {
860 sock_hold(&tfile->sk);
861 tun_napi_init(tun, tfile, napi);
862 }
863
864 tun_set_real_num_queues(tun);
865
866 /* device is allowed to go away first, so no need to hold extra
867 * refcnt.
868 */
869
870 out:
871 return err;
872 }
873
874 static struct tun_struct *tun_get(struct tun_file *tfile)
875 {
876 struct tun_struct *tun;
877
878 rcu_read_lock();
879 tun = rcu_dereference(tfile->tun);
880 if (tun)
881 dev_hold(tun->dev);
882 rcu_read_unlock();
883
884 return tun;
885 }
886
887 static void tun_put(struct tun_struct *tun)
888 {
889 dev_put(tun->dev);
890 }
891
892 /* TAP filtering */
893 static void addr_hash_set(u32 *mask, const u8 *addr)
894 {
895 int n = ether_crc(ETH_ALEN, addr) >> 26;
896 mask[n >> 5] |= (1 << (n & 31));
897 }
898
899 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
900 {
901 int n = ether_crc(ETH_ALEN, addr) >> 26;
902 return mask[n >> 5] & (1 << (n & 31));
903 }
904
905 static int update_filter(struct tap_filter *filter, void __user *arg)
906 {
907 struct { u8 u[ETH_ALEN]; } *addr;
908 struct tun_filter uf;
909 int err, alen, n, nexact;
910
911 if (copy_from_user(&uf, arg, sizeof(uf)))
912 return -EFAULT;
913
914 if (!uf.count) {
915 /* Disabled */
916 filter->count = 0;
917 return 0;
918 }
919
920 alen = ETH_ALEN * uf.count;
921 addr = memdup_user(arg + sizeof(uf), alen);
922 if (IS_ERR(addr))
923 return PTR_ERR(addr);
924
925 /* The filter is updated without holding any locks. Which is
926 * perfectly safe. We disable it first and in the worst
927 * case we'll accept a few undesired packets. */
928 filter->count = 0;
929 wmb();
930
931 /* Use first set of addresses as an exact filter */
932 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
933 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
934
935 nexact = n;
936
937 /* Remaining multicast addresses are hashed,
938 * unicast will leave the filter disabled. */
939 memset(filter->mask, 0, sizeof(filter->mask));
940 for (; n < uf.count; n++) {
941 if (!is_multicast_ether_addr(addr[n].u)) {
942 err = 0; /* no filter */
943 goto free_addr;
944 }
945 addr_hash_set(filter->mask, addr[n].u);
946 }
947
948 /* For ALLMULTI just set the mask to all ones.
949 * This overrides the mask populated above. */
950 if ((uf.flags & TUN_FLT_ALLMULTI))
951 memset(filter->mask, ~0, sizeof(filter->mask));
952
953 /* Now enable the filter */
954 wmb();
955 filter->count = nexact;
956
957 /* Return the number of exact filters */
958 err = nexact;
959 free_addr:
960 kfree(addr);
961 return err;
962 }
963
964 /* Returns: 0 - drop, !=0 - accept */
965 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
966 {
967 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
968 * at this point. */
969 struct ethhdr *eh = (struct ethhdr *) skb->data;
970 int i;
971
972 /* Exact match */
973 for (i = 0; i < filter->count; i++)
974 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
975 return 1;
976
977 /* Inexact match (multicast only) */
978 if (is_multicast_ether_addr(eh->h_dest))
979 return addr_hash_test(filter->mask, eh->h_dest);
980
981 return 0;
982 }
983
984 /*
985 * Checks whether the packet is accepted or not.
986 * Returns: 0 - drop, !=0 - accept
987 */
988 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
989 {
990 if (!filter->count)
991 return 1;
992
993 return run_filter(filter, skb);
994 }
995
996 /* Network device part of the driver */
997
998 static const struct ethtool_ops tun_ethtool_ops;
999
1000 /* Net device detach from fd. */
1001 static void tun_net_uninit(struct net_device *dev)
1002 {
1003 tun_detach_all(dev);
1004 }
1005
1006 /* Net device open. */
1007 static int tun_net_open(struct net_device *dev)
1008 {
1009 struct tun_struct *tun = netdev_priv(dev);
1010 int i;
1011
1012 netif_tx_start_all_queues(dev);
1013
1014 for (i = 0; i < tun->numqueues; i++) {
1015 struct tun_file *tfile;
1016
1017 tfile = rtnl_dereference(tun->tfiles[i]);
1018 tfile->socket.sk->sk_write_space(tfile->socket.sk);
1019 }
1020
1021 return 0;
1022 }
1023
1024 /* Net device close. */
1025 static int tun_net_close(struct net_device *dev)
1026 {
1027 netif_tx_stop_all_queues(dev);
1028 return 0;
1029 }
1030
1031 /* Net device start xmit */
1032 static void tun_automq_xmit(struct tun_struct *tun, struct sk_buff *skb)
1033 {
1034 #ifdef CONFIG_RPS
1035 if (tun->numqueues == 1 && static_key_false(&rps_needed)) {
1036 /* Select queue was not called for the skbuff, so we extract the
1037 * RPS hash and save it into the flow_table here.
1038 */
1039 __u32 rxhash;
1040
1041 rxhash = __skb_get_hash_symmetric(skb);
1042 if (rxhash) {
1043 struct tun_flow_entry *e;
1044 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)],
1045 rxhash);
1046 if (e)
1047 tun_flow_save_rps_rxhash(e, rxhash);
1048 }
1049 }
1050 #endif
1051 }
1052
1053 static unsigned int run_ebpf_filter(struct tun_struct *tun,
1054 struct sk_buff *skb,
1055 int len)
1056 {
1057 struct tun_prog *prog = rcu_dereference(tun->filter_prog);
1058
1059 if (prog)
1060 len = bpf_prog_run_clear_cb(prog->prog, skb);
1061
1062 return len;
1063 }
1064
1065 /* Net device start xmit */
1066 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
1067 {
1068 struct tun_struct *tun = netdev_priv(dev);
1069 int txq = skb->queue_mapping;
1070 struct tun_file *tfile;
1071 int len = skb->len;
1072
1073 rcu_read_lock();
1074 tfile = rcu_dereference(tun->tfiles[txq]);
1075
1076 /* Drop packet if interface is not attached */
1077 if (txq >= tun->numqueues)
1078 goto drop;
1079
1080 if (!rcu_dereference(tun->steering_prog))
1081 tun_automq_xmit(tun, skb);
1082
1083 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
1084
1085 BUG_ON(!tfile);
1086
1087 /* Drop if the filter does not like it.
1088 * This is a noop if the filter is disabled.
1089 * Filter can be enabled only for the TAP devices. */
1090 if (!check_filter(&tun->txflt, skb))
1091 goto drop;
1092
1093 if (tfile->socket.sk->sk_filter &&
1094 sk_filter(tfile->socket.sk, skb))
1095 goto drop;
1096
1097 len = run_ebpf_filter(tun, skb, len);
1098
1099 /* Trim extra bytes since we may insert vlan proto & TCI
1100 * in tun_put_user().
1101 */
1102 len -= skb_vlan_tag_present(skb) ? sizeof(struct veth) : 0;
1103 if (len <= 0 || pskb_trim(skb, len))
1104 goto drop;
1105
1106 if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC)))
1107 goto drop;
1108
1109 skb_tx_timestamp(skb);
1110
1111 /* Orphan the skb - required as we might hang on to it
1112 * for indefinite time.
1113 */
1114 skb_orphan(skb);
1115
1116 nf_reset(skb);
1117
1118 if (ptr_ring_produce(&tfile->tx_ring, skb))
1119 goto drop;
1120
1121 /* Notify and wake up reader process */
1122 if (tfile->flags & TUN_FASYNC)
1123 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1124 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1125
1126 rcu_read_unlock();
1127 return NETDEV_TX_OK;
1128
1129 drop:
1130 this_cpu_inc(tun->pcpu_stats->tx_dropped);
1131 skb_tx_error(skb);
1132 kfree_skb(skb);
1133 rcu_read_unlock();
1134 return NET_XMIT_DROP;
1135 }
1136
1137 static void tun_net_mclist(struct net_device *dev)
1138 {
1139 /*
1140 * This callback is supposed to deal with mc filter in
1141 * _rx_ path and has nothing to do with the _tx_ path.
1142 * In rx path we always accept everything userspace gives us.
1143 */
1144 }
1145
1146 static netdev_features_t tun_net_fix_features(struct net_device *dev,
1147 netdev_features_t features)
1148 {
1149 struct tun_struct *tun = netdev_priv(dev);
1150
1151 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
1152 }
1153 #ifdef CONFIG_NET_POLL_CONTROLLER
1154 static void tun_poll_controller(struct net_device *dev)
1155 {
1156 /*
1157 * Tun only receives frames when:
1158 * 1) the char device endpoint gets data from user space
1159 * 2) the tun socket gets a sendmsg call from user space
1160 * If NAPI is not enabled, since both of those are synchronous
1161 * operations, we are guaranteed never to have pending data when we poll
1162 * for it so there is nothing to do here but return.
1163 * We need this though so netpoll recognizes us as an interface that
1164 * supports polling, which enables bridge devices in virt setups to
1165 * still use netconsole
1166 * If NAPI is enabled, however, we need to schedule polling for all
1167 * queues unless we are using napi_gro_frags(), which we call in
1168 * process context and not in NAPI context.
1169 */
1170 struct tun_struct *tun = netdev_priv(dev);
1171
1172 if (tun->flags & IFF_NAPI) {
1173 struct tun_file *tfile;
1174 int i;
1175
1176 if (tun_napi_frags_enabled(tun))
1177 return;
1178
1179 rcu_read_lock();
1180 for (i = 0; i < tun->numqueues; i++) {
1181 tfile = rcu_dereference(tun->tfiles[i]);
1182 if (tfile->napi_enabled)
1183 napi_schedule(&tfile->napi);
1184 }
1185 rcu_read_unlock();
1186 }
1187 return;
1188 }
1189 #endif
1190
1191 static void tun_set_headroom(struct net_device *dev, int new_hr)
1192 {
1193 struct tun_struct *tun = netdev_priv(dev);
1194
1195 if (new_hr < NET_SKB_PAD)
1196 new_hr = NET_SKB_PAD;
1197
1198 tun->align = new_hr;
1199 }
1200
1201 static void
1202 tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
1203 {
1204 u32 rx_dropped = 0, tx_dropped = 0, rx_frame_errors = 0;
1205 struct tun_struct *tun = netdev_priv(dev);
1206 struct tun_pcpu_stats *p;
1207 int i;
1208
1209 for_each_possible_cpu(i) {
1210 u64 rxpackets, rxbytes, txpackets, txbytes;
1211 unsigned int start;
1212
1213 p = per_cpu_ptr(tun->pcpu_stats, i);
1214 do {
1215 start = u64_stats_fetch_begin(&p->syncp);
1216 rxpackets = p->rx_packets;
1217 rxbytes = p->rx_bytes;
1218 txpackets = p->tx_packets;
1219 txbytes = p->tx_bytes;
1220 } while (u64_stats_fetch_retry(&p->syncp, start));
1221
1222 stats->rx_packets += rxpackets;
1223 stats->rx_bytes += rxbytes;
1224 stats->tx_packets += txpackets;
1225 stats->tx_bytes += txbytes;
1226
1227 /* u32 counters */
1228 rx_dropped += p->rx_dropped;
1229 rx_frame_errors += p->rx_frame_errors;
1230 tx_dropped += p->tx_dropped;
1231 }
1232 stats->rx_dropped = rx_dropped;
1233 stats->rx_frame_errors = rx_frame_errors;
1234 stats->tx_dropped = tx_dropped;
1235 }
1236
1237 static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1238 struct netlink_ext_ack *extack)
1239 {
1240 struct tun_struct *tun = netdev_priv(dev);
1241 struct bpf_prog *old_prog;
1242
1243 old_prog = rtnl_dereference(tun->xdp_prog);
1244 rcu_assign_pointer(tun->xdp_prog, prog);
1245 if (old_prog)
1246 bpf_prog_put(old_prog);
1247
1248 return 0;
1249 }
1250
1251 static u32 tun_xdp_query(struct net_device *dev)
1252 {
1253 struct tun_struct *tun = netdev_priv(dev);
1254 const struct bpf_prog *xdp_prog;
1255
1256 xdp_prog = rtnl_dereference(tun->xdp_prog);
1257 if (xdp_prog)
1258 return xdp_prog->aux->id;
1259
1260 return 0;
1261 }
1262
1263 static int tun_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1264 {
1265 switch (xdp->command) {
1266 case XDP_SETUP_PROG:
1267 return tun_xdp_set(dev, xdp->prog, xdp->extack);
1268 case XDP_QUERY_PROG:
1269 xdp->prog_id = tun_xdp_query(dev);
1270 xdp->prog_attached = !!xdp->prog_id;
1271 return 0;
1272 default:
1273 return -EINVAL;
1274 }
1275 }
1276
1277 static const struct net_device_ops tun_netdev_ops = {
1278 .ndo_uninit = tun_net_uninit,
1279 .ndo_open = tun_net_open,
1280 .ndo_stop = tun_net_close,
1281 .ndo_start_xmit = tun_net_xmit,
1282 .ndo_fix_features = tun_net_fix_features,
1283 .ndo_select_queue = tun_select_queue,
1284 #ifdef CONFIG_NET_POLL_CONTROLLER
1285 .ndo_poll_controller = tun_poll_controller,
1286 #endif
1287 .ndo_set_rx_headroom = tun_set_headroom,
1288 .ndo_get_stats64 = tun_net_get_stats64,
1289 };
1290
1291 static int tun_xdp_xmit(struct net_device *dev, struct xdp_buff *xdp)
1292 {
1293 struct tun_struct *tun = netdev_priv(dev);
1294 struct xdp_buff *buff = xdp->data_hard_start;
1295 int headroom = xdp->data - xdp->data_hard_start;
1296 struct tun_file *tfile;
1297 u32 numqueues;
1298 int ret = 0;
1299
1300 /* Assure headroom is available and buff is properly aligned */
1301 if (unlikely(headroom < sizeof(*xdp) || tun_is_xdp_buff(xdp)))
1302 return -ENOSPC;
1303
1304 *buff = *xdp;
1305
1306 rcu_read_lock();
1307
1308 numqueues = READ_ONCE(tun->numqueues);
1309 if (!numqueues) {
1310 ret = -ENOSPC;
1311 goto out;
1312 }
1313
1314 tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
1315 numqueues]);
1316 /* Encode the XDP flag into lowest bit for consumer to differ
1317 * XDP buffer from sk_buff.
1318 */
1319 if (ptr_ring_produce(&tfile->tx_ring, tun_xdp_to_ptr(buff))) {
1320 this_cpu_inc(tun->pcpu_stats->tx_dropped);
1321 ret = -ENOSPC;
1322 }
1323
1324 out:
1325 rcu_read_unlock();
1326 return ret;
1327 }
1328
1329 static void tun_xdp_flush(struct net_device *dev)
1330 {
1331 struct tun_struct *tun = netdev_priv(dev);
1332 struct tun_file *tfile;
1333 u32 numqueues;
1334
1335 rcu_read_lock();
1336
1337 numqueues = READ_ONCE(tun->numqueues);
1338 if (!numqueues)
1339 goto out;
1340
1341 tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
1342 numqueues]);
1343 /* Notify and wake up reader process */
1344 if (tfile->flags & TUN_FASYNC)
1345 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1346 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1347
1348 out:
1349 rcu_read_unlock();
1350 }
1351
1352 static const struct net_device_ops tap_netdev_ops = {
1353 .ndo_uninit = tun_net_uninit,
1354 .ndo_open = tun_net_open,
1355 .ndo_stop = tun_net_close,
1356 .ndo_start_xmit = tun_net_xmit,
1357 .ndo_fix_features = tun_net_fix_features,
1358 .ndo_set_rx_mode = tun_net_mclist,
1359 .ndo_set_mac_address = eth_mac_addr,
1360 .ndo_validate_addr = eth_validate_addr,
1361 .ndo_select_queue = tun_select_queue,
1362 #ifdef CONFIG_NET_POLL_CONTROLLER
1363 .ndo_poll_controller = tun_poll_controller,
1364 #endif
1365 .ndo_features_check = passthru_features_check,
1366 .ndo_set_rx_headroom = tun_set_headroom,
1367 .ndo_get_stats64 = tun_net_get_stats64,
1368 .ndo_bpf = tun_xdp,
1369 .ndo_xdp_xmit = tun_xdp_xmit,
1370 .ndo_xdp_flush = tun_xdp_flush,
1371 };
1372
1373 static void tun_flow_init(struct tun_struct *tun)
1374 {
1375 int i;
1376
1377 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1378 INIT_HLIST_HEAD(&tun->flows[i]);
1379
1380 tun->ageing_time = TUN_FLOW_EXPIRE;
1381 timer_setup(&tun->flow_gc_timer, tun_flow_cleanup, 0);
1382 mod_timer(&tun->flow_gc_timer,
1383 round_jiffies_up(jiffies + tun->ageing_time));
1384 }
1385
1386 static void tun_flow_uninit(struct tun_struct *tun)
1387 {
1388 del_timer_sync(&tun->flow_gc_timer);
1389 tun_flow_flush(tun);
1390 }
1391
1392 #define MIN_MTU 68
1393 #define MAX_MTU 65535
1394
1395 /* Initialize net device. */
1396 static void tun_net_init(struct net_device *dev)
1397 {
1398 struct tun_struct *tun = netdev_priv(dev);
1399
1400 switch (tun->flags & TUN_TYPE_MASK) {
1401 case IFF_TUN:
1402 dev->netdev_ops = &tun_netdev_ops;
1403
1404 /* Point-to-Point TUN Device */
1405 dev->hard_header_len = 0;
1406 dev->addr_len = 0;
1407 dev->mtu = 1500;
1408
1409 /* Zero header length */
1410 dev->type = ARPHRD_NONE;
1411 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1412 break;
1413
1414 case IFF_TAP:
1415 dev->netdev_ops = &tap_netdev_ops;
1416 /* Ethernet TAP Device */
1417 ether_setup(dev);
1418 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1419 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1420
1421 eth_hw_addr_random(dev);
1422
1423 break;
1424 }
1425
1426 dev->min_mtu = MIN_MTU;
1427 dev->max_mtu = MAX_MTU - dev->hard_header_len;
1428 }
1429
1430 /* Character device part */
1431
1432 /* Poll */
1433 static __poll_t tun_chr_poll(struct file *file, poll_table *wait)
1434 {
1435 struct tun_file *tfile = file->private_data;
1436 struct tun_struct *tun = tun_get(tfile);
1437 struct sock *sk;
1438 __poll_t mask = 0;
1439
1440 if (!tun)
1441 return EPOLLERR;
1442
1443 sk = tfile->socket.sk;
1444
1445 tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
1446
1447 poll_wait(file, sk_sleep(sk), wait);
1448
1449 if (!ptr_ring_empty(&tfile->tx_ring))
1450 mask |= EPOLLIN | EPOLLRDNORM;
1451
1452 if (tun->dev->flags & IFF_UP &&
1453 (sock_writeable(sk) ||
1454 (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1455 sock_writeable(sk))))
1456 mask |= EPOLLOUT | EPOLLWRNORM;
1457
1458 if (tun->dev->reg_state != NETREG_REGISTERED)
1459 mask = EPOLLERR;
1460
1461 tun_put(tun);
1462 return mask;
1463 }
1464
1465 static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile,
1466 size_t len,
1467 const struct iov_iter *it)
1468 {
1469 struct sk_buff *skb;
1470 size_t linear;
1471 int err;
1472 int i;
1473
1474 if (it->nr_segs > MAX_SKB_FRAGS + 1)
1475 return ERR_PTR(-ENOMEM);
1476
1477 local_bh_disable();
1478 skb = napi_get_frags(&tfile->napi);
1479 local_bh_enable();
1480 if (!skb)
1481 return ERR_PTR(-ENOMEM);
1482
1483 linear = iov_iter_single_seg_count(it);
1484 err = __skb_grow(skb, linear);
1485 if (err)
1486 goto free;
1487
1488 skb->len = len;
1489 skb->data_len = len - linear;
1490 skb->truesize += skb->data_len;
1491
1492 for (i = 1; i < it->nr_segs; i++) {
1493 struct page_frag *pfrag = &current->task_frag;
1494 size_t fragsz = it->iov[i].iov_len;
1495
1496 if (fragsz == 0 || fragsz > PAGE_SIZE) {
1497 err = -EINVAL;
1498 goto free;
1499 }
1500
1501 if (!skb_page_frag_refill(fragsz, pfrag, GFP_KERNEL)) {
1502 err = -ENOMEM;
1503 goto free;
1504 }
1505
1506 skb_fill_page_desc(skb, i - 1, pfrag->page,
1507 pfrag->offset, fragsz);
1508 page_ref_inc(pfrag->page);
1509 pfrag->offset += fragsz;
1510 }
1511
1512 return skb;
1513 free:
1514 /* frees skb and all frags allocated with napi_alloc_frag() */
1515 napi_free_frags(&tfile->napi);
1516 return ERR_PTR(err);
1517 }
1518
1519 /* prepad is the amount to reserve at front. len is length after that.
1520 * linear is a hint as to how much to copy (usually headers). */
1521 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1522 size_t prepad, size_t len,
1523 size_t linear, int noblock)
1524 {
1525 struct sock *sk = tfile->socket.sk;
1526 struct sk_buff *skb;
1527 int err;
1528
1529 /* Under a page? Don't bother with paged skb. */
1530 if (prepad + len < PAGE_SIZE || !linear)
1531 linear = len;
1532
1533 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1534 &err, 0);
1535 if (!skb)
1536 return ERR_PTR(err);
1537
1538 skb_reserve(skb, prepad);
1539 skb_put(skb, linear);
1540 skb->data_len = len - linear;
1541 skb->len += len - linear;
1542
1543 return skb;
1544 }
1545
1546 static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile,
1547 struct sk_buff *skb, int more)
1548 {
1549 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1550 struct sk_buff_head process_queue;
1551 u32 rx_batched = tun->rx_batched;
1552 bool rcv = false;
1553
1554 if (!rx_batched || (!more && skb_queue_empty(queue))) {
1555 local_bh_disable();
1556 netif_receive_skb(skb);
1557 local_bh_enable();
1558 return;
1559 }
1560
1561 spin_lock(&queue->lock);
1562 if (!more || skb_queue_len(queue) == rx_batched) {
1563 __skb_queue_head_init(&process_queue);
1564 skb_queue_splice_tail_init(queue, &process_queue);
1565 rcv = true;
1566 } else {
1567 __skb_queue_tail(queue, skb);
1568 }
1569 spin_unlock(&queue->lock);
1570
1571 if (rcv) {
1572 struct sk_buff *nskb;
1573
1574 local_bh_disable();
1575 while ((nskb = __skb_dequeue(&process_queue)))
1576 netif_receive_skb(nskb);
1577 netif_receive_skb(skb);
1578 local_bh_enable();
1579 }
1580 }
1581
1582 static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile,
1583 int len, int noblock, bool zerocopy)
1584 {
1585 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
1586 return false;
1587
1588 if (tfile->socket.sk->sk_sndbuf != INT_MAX)
1589 return false;
1590
1591 if (!noblock)
1592 return false;
1593
1594 if (zerocopy)
1595 return false;
1596
1597 if (SKB_DATA_ALIGN(len + TUN_RX_PAD) +
1598 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
1599 return false;
1600
1601 return true;
1602 }
1603
1604 static struct sk_buff *tun_build_skb(struct tun_struct *tun,
1605 struct tun_file *tfile,
1606 struct iov_iter *from,
1607 struct virtio_net_hdr *hdr,
1608 int len, int *skb_xdp)
1609 {
1610 struct page_frag *alloc_frag = &current->task_frag;
1611 struct sk_buff *skb;
1612 struct bpf_prog *xdp_prog;
1613 int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1614 unsigned int delta = 0;
1615 char *buf;
1616 size_t copied;
1617 int err, pad = TUN_RX_PAD;
1618
1619 rcu_read_lock();
1620 xdp_prog = rcu_dereference(tun->xdp_prog);
1621 if (xdp_prog)
1622 pad += TUN_HEADROOM;
1623 buflen += SKB_DATA_ALIGN(len + pad);
1624 rcu_read_unlock();
1625
1626 alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES);
1627 if (unlikely(!skb_page_frag_refill(buflen, alloc_frag, GFP_KERNEL)))
1628 return ERR_PTR(-ENOMEM);
1629
1630 buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
1631 copied = copy_page_from_iter(alloc_frag->page,
1632 alloc_frag->offset + pad,
1633 len, from);
1634 if (copied != len)
1635 return ERR_PTR(-EFAULT);
1636
1637 /* There's a small window that XDP may be set after the check
1638 * of xdp_prog above, this should be rare and for simplicity
1639 * we do XDP on skb in case the headroom is not enough.
1640 */
1641 if (hdr->gso_type || !xdp_prog)
1642 *skb_xdp = 1;
1643 else
1644 *skb_xdp = 0;
1645
1646 preempt_disable();
1647 rcu_read_lock();
1648 xdp_prog = rcu_dereference(tun->xdp_prog);
1649 if (xdp_prog && !*skb_xdp) {
1650 struct xdp_buff xdp;
1651 void *orig_data;
1652 u32 act;
1653
1654 xdp.data_hard_start = buf;
1655 xdp.data = buf + pad;
1656 xdp_set_data_meta_invalid(&xdp);
1657 xdp.data_end = xdp.data + len;
1658 xdp.rxq = &tfile->xdp_rxq;
1659 orig_data = xdp.data;
1660 act = bpf_prog_run_xdp(xdp_prog, &xdp);
1661
1662 switch (act) {
1663 case XDP_REDIRECT:
1664 get_page(alloc_frag->page);
1665 alloc_frag->offset += buflen;
1666 err = xdp_do_redirect(tun->dev, &xdp, xdp_prog);
1667 xdp_do_flush_map();
1668 if (err)
1669 goto err_redirect;
1670 rcu_read_unlock();
1671 preempt_enable();
1672 return NULL;
1673 case XDP_TX:
1674 get_page(alloc_frag->page);
1675 alloc_frag->offset += buflen;
1676 if (tun_xdp_xmit(tun->dev, &xdp))
1677 goto err_redirect;
1678 tun_xdp_flush(tun->dev);
1679 rcu_read_unlock();
1680 preempt_enable();
1681 return NULL;
1682 case XDP_PASS:
1683 delta = orig_data - xdp.data;
1684 break;
1685 default:
1686 bpf_warn_invalid_xdp_action(act);
1687 /* fall through */
1688 case XDP_ABORTED:
1689 trace_xdp_exception(tun->dev, xdp_prog, act);
1690 /* fall through */
1691 case XDP_DROP:
1692 goto err_xdp;
1693 }
1694 }
1695
1696 skb = build_skb(buf, buflen);
1697 if (!skb) {
1698 rcu_read_unlock();
1699 preempt_enable();
1700 return ERR_PTR(-ENOMEM);
1701 }
1702
1703 skb_reserve(skb, pad - delta);
1704 skb_put(skb, len + delta);
1705 get_page(alloc_frag->page);
1706 alloc_frag->offset += buflen;
1707
1708 rcu_read_unlock();
1709 preempt_enable();
1710
1711 return skb;
1712
1713 err_redirect:
1714 put_page(alloc_frag->page);
1715 err_xdp:
1716 rcu_read_unlock();
1717 preempt_enable();
1718 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1719 return NULL;
1720 }
1721
1722 /* Get packet from user space buffer */
1723 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1724 void *msg_control, struct iov_iter *from,
1725 int noblock, bool more)
1726 {
1727 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1728 struct sk_buff *skb;
1729 size_t total_len = iov_iter_count(from);
1730 size_t len = total_len, align = tun->align, linear;
1731 struct virtio_net_hdr gso = { 0 };
1732 struct tun_pcpu_stats *stats;
1733 int good_linear;
1734 int copylen;
1735 bool zerocopy = false;
1736 int err;
1737 u32 rxhash = 0;
1738 int skb_xdp = 1;
1739 bool frags = tun_napi_frags_enabled(tun);
1740
1741 if (!(tun->dev->flags & IFF_UP))
1742 return -EIO;
1743
1744 if (!(tun->flags & IFF_NO_PI)) {
1745 if (len < sizeof(pi))
1746 return -EINVAL;
1747 len -= sizeof(pi);
1748
1749 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1750 return -EFAULT;
1751 }
1752
1753 if (tun->flags & IFF_VNET_HDR) {
1754 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1755
1756 if (len < vnet_hdr_sz)
1757 return -EINVAL;
1758 len -= vnet_hdr_sz;
1759
1760 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1761 return -EFAULT;
1762
1763 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1764 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1765 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1766
1767 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1768 return -EINVAL;
1769 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1770 }
1771
1772 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1773 align += NET_IP_ALIGN;
1774 if (unlikely(len < ETH_HLEN ||
1775 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1776 return -EINVAL;
1777 }
1778
1779 good_linear = SKB_MAX_HEAD(align);
1780
1781 if (msg_control) {
1782 struct iov_iter i = *from;
1783
1784 /* There are 256 bytes to be copied in skb, so there is
1785 * enough room for skb expand head in case it is used.
1786 * The rest of the buffer is mapped from userspace.
1787 */
1788 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1789 if (copylen > good_linear)
1790 copylen = good_linear;
1791 linear = copylen;
1792 iov_iter_advance(&i, copylen);
1793 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1794 zerocopy = true;
1795 }
1796
1797 if (!frags && tun_can_build_skb(tun, tfile, len, noblock, zerocopy)) {
1798 /* For the packet that is not easy to be processed
1799 * (e.g gso or jumbo packet), we will do it at after
1800 * skb was created with generic XDP routine.
1801 */
1802 skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp);
1803 if (IS_ERR(skb)) {
1804 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1805 return PTR_ERR(skb);
1806 }
1807 if (!skb)
1808 return total_len;
1809 } else {
1810 if (!zerocopy) {
1811 copylen = len;
1812 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1813 linear = good_linear;
1814 else
1815 linear = tun16_to_cpu(tun, gso.hdr_len);
1816 }
1817
1818 if (frags) {
1819 mutex_lock(&tfile->napi_mutex);
1820 skb = tun_napi_alloc_frags(tfile, copylen, from);
1821 /* tun_napi_alloc_frags() enforces a layout for the skb.
1822 * If zerocopy is enabled, then this layout will be
1823 * overwritten by zerocopy_sg_from_iter().
1824 */
1825 zerocopy = false;
1826 } else {
1827 skb = tun_alloc_skb(tfile, align, copylen, linear,
1828 noblock);
1829 }
1830
1831 if (IS_ERR(skb)) {
1832 if (PTR_ERR(skb) != -EAGAIN)
1833 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1834 if (frags)
1835 mutex_unlock(&tfile->napi_mutex);
1836 return PTR_ERR(skb);
1837 }
1838
1839 if (zerocopy)
1840 err = zerocopy_sg_from_iter(skb, from);
1841 else
1842 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1843
1844 if (err) {
1845 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1846 kfree_skb(skb);
1847 if (frags) {
1848 tfile->napi.skb = NULL;
1849 mutex_unlock(&tfile->napi_mutex);
1850 }
1851
1852 return -EFAULT;
1853 }
1854 }
1855
1856 if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1857 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
1858 kfree_skb(skb);
1859 if (frags) {
1860 tfile->napi.skb = NULL;
1861 mutex_unlock(&tfile->napi_mutex);
1862 }
1863
1864 return -EINVAL;
1865 }
1866
1867 switch (tun->flags & TUN_TYPE_MASK) {
1868 case IFF_TUN:
1869 if (tun->flags & IFF_NO_PI) {
1870 u8 ip_version = skb->len ? (skb->data[0] >> 4) : 0;
1871
1872 switch (ip_version) {
1873 case 4:
1874 pi.proto = htons(ETH_P_IP);
1875 break;
1876 case 6:
1877 pi.proto = htons(ETH_P_IPV6);
1878 break;
1879 default:
1880 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1881 kfree_skb(skb);
1882 return -EINVAL;
1883 }
1884 }
1885
1886 skb_reset_mac_header(skb);
1887 skb->protocol = pi.proto;
1888 skb->dev = tun->dev;
1889 break;
1890 case IFF_TAP:
1891 if (!frags)
1892 skb->protocol = eth_type_trans(skb, tun->dev);
1893 break;
1894 }
1895
1896 /* copy skb_ubuf_info for callback when skb has no error */
1897 if (zerocopy) {
1898 skb_shinfo(skb)->destructor_arg = msg_control;
1899 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1900 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1901 } else if (msg_control) {
1902 struct ubuf_info *uarg = msg_control;
1903 uarg->callback(uarg, false);
1904 }
1905
1906 skb_reset_network_header(skb);
1907 skb_probe_transport_header(skb, 0);
1908
1909 if (skb_xdp) {
1910 struct bpf_prog *xdp_prog;
1911 int ret;
1912
1913 rcu_read_lock();
1914 xdp_prog = rcu_dereference(tun->xdp_prog);
1915 if (xdp_prog) {
1916 ret = do_xdp_generic(xdp_prog, skb);
1917 if (ret != XDP_PASS) {
1918 rcu_read_unlock();
1919 return total_len;
1920 }
1921 }
1922 rcu_read_unlock();
1923 }
1924
1925 rcu_read_lock();
1926 if (!rcu_dereference(tun->steering_prog))
1927 rxhash = __skb_get_hash_symmetric(skb);
1928 rcu_read_unlock();
1929
1930 if (frags) {
1931 /* Exercise flow dissector code path. */
1932 u32 headlen = eth_get_headlen(skb->data, skb_headlen(skb));
1933
1934 if (unlikely(headlen > skb_headlen(skb))) {
1935 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1936 napi_free_frags(&tfile->napi);
1937 mutex_unlock(&tfile->napi_mutex);
1938 WARN_ON(1);
1939 return -ENOMEM;
1940 }
1941
1942 local_bh_disable();
1943 napi_gro_frags(&tfile->napi);
1944 local_bh_enable();
1945 mutex_unlock(&tfile->napi_mutex);
1946 } else if (tfile->napi_enabled) {
1947 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1948 int queue_len;
1949
1950 spin_lock_bh(&queue->lock);
1951 __skb_queue_tail(queue, skb);
1952 queue_len = skb_queue_len(queue);
1953 spin_unlock(&queue->lock);
1954
1955 if (!more || queue_len > NAPI_POLL_WEIGHT)
1956 napi_schedule(&tfile->napi);
1957
1958 local_bh_enable();
1959 } else if (!IS_ENABLED(CONFIG_4KSTACKS)) {
1960 tun_rx_batched(tun, tfile, skb, more);
1961 } else {
1962 netif_rx_ni(skb);
1963 }
1964
1965 stats = get_cpu_ptr(tun->pcpu_stats);
1966 u64_stats_update_begin(&stats->syncp);
1967 stats->rx_packets++;
1968 stats->rx_bytes += len;
1969 u64_stats_update_end(&stats->syncp);
1970 put_cpu_ptr(stats);
1971
1972 if (rxhash)
1973 tun_flow_update(tun, rxhash, tfile);
1974
1975 return total_len;
1976 }
1977
1978 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
1979 {
1980 struct file *file = iocb->ki_filp;
1981 struct tun_file *tfile = file->private_data;
1982 struct tun_struct *tun = tun_get(tfile);
1983 ssize_t result;
1984
1985 if (!tun)
1986 return -EBADFD;
1987
1988 result = tun_get_user(tun, tfile, NULL, from,
1989 file->f_flags & O_NONBLOCK, false);
1990
1991 tun_put(tun);
1992 return result;
1993 }
1994
1995 static ssize_t tun_put_user_xdp(struct tun_struct *tun,
1996 struct tun_file *tfile,
1997 struct xdp_buff *xdp,
1998 struct iov_iter *iter)
1999 {
2000 int vnet_hdr_sz = 0;
2001 size_t size = xdp->data_end - xdp->data;
2002 struct tun_pcpu_stats *stats;
2003 size_t ret;
2004
2005 if (tun->flags & IFF_VNET_HDR) {
2006 struct virtio_net_hdr gso = { 0 };
2007
2008 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2009 if (unlikely(iov_iter_count(iter) < vnet_hdr_sz))
2010 return -EINVAL;
2011 if (unlikely(copy_to_iter(&gso, sizeof(gso), iter) !=
2012 sizeof(gso)))
2013 return -EFAULT;
2014 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2015 }
2016
2017 ret = copy_to_iter(xdp->data, size, iter) + vnet_hdr_sz;
2018
2019 stats = get_cpu_ptr(tun->pcpu_stats);
2020 u64_stats_update_begin(&stats->syncp);
2021 stats->tx_packets++;
2022 stats->tx_bytes += ret;
2023 u64_stats_update_end(&stats->syncp);
2024 put_cpu_ptr(tun->pcpu_stats);
2025
2026 return ret;
2027 }
2028
2029 /* Put packet to the user space buffer */
2030 static ssize_t tun_put_user(struct tun_struct *tun,
2031 struct tun_file *tfile,
2032 struct sk_buff *skb,
2033 struct iov_iter *iter)
2034 {
2035 struct tun_pi pi = { 0, skb->protocol };
2036 struct tun_pcpu_stats *stats;
2037 ssize_t total;
2038 int vlan_offset = 0;
2039 int vlan_hlen = 0;
2040 int vnet_hdr_sz = 0;
2041
2042 if (skb_vlan_tag_present(skb))
2043 vlan_hlen = VLAN_HLEN;
2044
2045 if (tun->flags & IFF_VNET_HDR)
2046 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2047
2048 total = skb->len + vlan_hlen + vnet_hdr_sz;
2049
2050 if (!(tun->flags & IFF_NO_PI)) {
2051 if (iov_iter_count(iter) < sizeof(pi))
2052 return -EINVAL;
2053
2054 total += sizeof(pi);
2055 if (iov_iter_count(iter) < total) {
2056 /* Packet will be striped */
2057 pi.flags |= TUN_PKT_STRIP;
2058 }
2059
2060 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
2061 return -EFAULT;
2062 }
2063
2064 if (vnet_hdr_sz) {
2065 struct virtio_net_hdr gso;
2066
2067 if (iov_iter_count(iter) < vnet_hdr_sz)
2068 return -EINVAL;
2069
2070 if (virtio_net_hdr_from_skb(skb, &gso,
2071 tun_is_little_endian(tun), true)) {
2072 struct skb_shared_info *sinfo = skb_shinfo(skb);
2073 pr_err("unexpected GSO type: "
2074 "0x%x, gso_size %d, hdr_len %d\n",
2075 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
2076 tun16_to_cpu(tun, gso.hdr_len));
2077 print_hex_dump(KERN_ERR, "tun: ",
2078 DUMP_PREFIX_NONE,
2079 16, 1, skb->head,
2080 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
2081 WARN_ON_ONCE(1);
2082 return -EINVAL;
2083 }
2084
2085 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
2086 return -EFAULT;
2087
2088 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2089 }
2090
2091 if (vlan_hlen) {
2092 int ret;
2093 struct veth veth;
2094
2095 veth.h_vlan_proto = skb->vlan_proto;
2096 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
2097
2098 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
2099
2100 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
2101 if (ret || !iov_iter_count(iter))
2102 goto done;
2103
2104 ret = copy_to_iter(&veth, sizeof(veth), iter);
2105 if (ret != sizeof(veth) || !iov_iter_count(iter))
2106 goto done;
2107 }
2108
2109 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
2110
2111 done:
2112 /* caller is in process context, */
2113 stats = get_cpu_ptr(tun->pcpu_stats);
2114 u64_stats_update_begin(&stats->syncp);
2115 stats->tx_packets++;
2116 stats->tx_bytes += skb->len + vlan_hlen;
2117 u64_stats_update_end(&stats->syncp);
2118 put_cpu_ptr(tun->pcpu_stats);
2119
2120 return total;
2121 }
2122
2123 static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err)
2124 {
2125 DECLARE_WAITQUEUE(wait, current);
2126 void *ptr = NULL;
2127 int error = 0;
2128
2129 ptr = ptr_ring_consume(&tfile->tx_ring);
2130 if (ptr)
2131 goto out;
2132 if (noblock) {
2133 error = -EAGAIN;
2134 goto out;
2135 }
2136
2137 add_wait_queue(&tfile->wq.wait, &wait);
2138 current->state = TASK_INTERRUPTIBLE;
2139
2140 while (1) {
2141 ptr = ptr_ring_consume(&tfile->tx_ring);
2142 if (ptr)
2143 break;
2144 if (signal_pending(current)) {
2145 error = -ERESTARTSYS;
2146 break;
2147 }
2148 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
2149 error = -EFAULT;
2150 break;
2151 }
2152
2153 schedule();
2154 }
2155
2156 current->state = TASK_RUNNING;
2157 remove_wait_queue(&tfile->wq.wait, &wait);
2158
2159 out:
2160 *err = error;
2161 return ptr;
2162 }
2163
2164 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
2165 struct iov_iter *to,
2166 int noblock, void *ptr)
2167 {
2168 ssize_t ret;
2169 int err;
2170
2171 tun_debug(KERN_INFO, tun, "tun_do_read\n");
2172
2173 if (!iov_iter_count(to)) {
2174 tun_ptr_free(ptr);
2175 return 0;
2176 }
2177
2178 if (!ptr) {
2179 /* Read frames from ring */
2180 ptr = tun_ring_recv(tfile, noblock, &err);
2181 if (!ptr)
2182 return err;
2183 }
2184
2185 if (tun_is_xdp_buff(ptr)) {
2186 struct xdp_buff *xdp = tun_ptr_to_xdp(ptr);
2187
2188 ret = tun_put_user_xdp(tun, tfile, xdp, to);
2189 put_page(virt_to_head_page(xdp->data));
2190 } else {
2191 struct sk_buff *skb = ptr;
2192
2193 ret = tun_put_user(tun, tfile, skb, to);
2194 if (unlikely(ret < 0))
2195 kfree_skb(skb);
2196 else
2197 consume_skb(skb);
2198 }
2199
2200 return ret;
2201 }
2202
2203 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
2204 {
2205 struct file *file = iocb->ki_filp;
2206 struct tun_file *tfile = file->private_data;
2207 struct tun_struct *tun = tun_get(tfile);
2208 ssize_t len = iov_iter_count(to), ret;
2209
2210 if (!tun)
2211 return -EBADFD;
2212 ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK, NULL);
2213 ret = min_t(ssize_t, ret, len);
2214 if (ret > 0)
2215 iocb->ki_pos = ret;
2216 tun_put(tun);
2217 return ret;
2218 }
2219
2220 static void tun_prog_free(struct rcu_head *rcu)
2221 {
2222 struct tun_prog *prog = container_of(rcu, struct tun_prog, rcu);
2223
2224 bpf_prog_destroy(prog->prog);
2225 kfree(prog);
2226 }
2227
2228 static int __tun_set_ebpf(struct tun_struct *tun,
2229 struct tun_prog __rcu **prog_p,
2230 struct bpf_prog *prog)
2231 {
2232 struct tun_prog *old, *new = NULL;
2233
2234 if (prog) {
2235 new = kmalloc(sizeof(*new), GFP_KERNEL);
2236 if (!new)
2237 return -ENOMEM;
2238 new->prog = prog;
2239 }
2240
2241 spin_lock_bh(&tun->lock);
2242 old = rcu_dereference_protected(*prog_p,
2243 lockdep_is_held(&tun->lock));
2244 rcu_assign_pointer(*prog_p, new);
2245 spin_unlock_bh(&tun->lock);
2246
2247 if (old)
2248 call_rcu(&old->rcu, tun_prog_free);
2249
2250 return 0;
2251 }
2252
2253 static void tun_free_netdev(struct net_device *dev)
2254 {
2255 struct tun_struct *tun = netdev_priv(dev);
2256
2257 BUG_ON(!(list_empty(&tun->disabled)));
2258 free_percpu(tun->pcpu_stats);
2259 tun_flow_uninit(tun);
2260 security_tun_dev_free_security(tun->security);
2261 __tun_set_ebpf(tun, &tun->steering_prog, NULL);
2262 __tun_set_ebpf(tun, &tun->filter_prog, NULL);
2263 }
2264
2265 static void tun_setup(struct net_device *dev)
2266 {
2267 struct tun_struct *tun = netdev_priv(dev);
2268
2269 tun->owner = INVALID_UID;
2270 tun->group = INVALID_GID;
2271
2272 dev->ethtool_ops = &tun_ethtool_ops;
2273 dev->needs_free_netdev = true;
2274 dev->priv_destructor = tun_free_netdev;
2275 /* We prefer our own queue length */
2276 dev->tx_queue_len = TUN_READQ_SIZE;
2277 }
2278
2279 /* Trivial set of netlink ops to allow deleting tun or tap
2280 * device with netlink.
2281 */
2282 static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
2283 struct netlink_ext_ack *extack)
2284 {
2285 return -EINVAL;
2286 }
2287
2288 static size_t tun_get_size(const struct net_device *dev)
2289 {
2290 BUILD_BUG_ON(sizeof(u32) != sizeof(uid_t));
2291 BUILD_BUG_ON(sizeof(u32) != sizeof(gid_t));
2292
2293 return nla_total_size(sizeof(uid_t)) + /* OWNER */
2294 nla_total_size(sizeof(gid_t)) + /* GROUP */
2295 nla_total_size(sizeof(u8)) + /* TYPE */
2296 nla_total_size(sizeof(u8)) + /* PI */
2297 nla_total_size(sizeof(u8)) + /* VNET_HDR */
2298 nla_total_size(sizeof(u8)) + /* PERSIST */
2299 nla_total_size(sizeof(u8)) + /* MULTI_QUEUE */
2300 nla_total_size(sizeof(u32)) + /* NUM_QUEUES */
2301 nla_total_size(sizeof(u32)) + /* NUM_DISABLED_QUEUES */
2302 0;
2303 }
2304
2305 static int tun_fill_info(struct sk_buff *skb, const struct net_device *dev)
2306 {
2307 struct tun_struct *tun = netdev_priv(dev);
2308
2309 if (nla_put_u8(skb, IFLA_TUN_TYPE, tun->flags & TUN_TYPE_MASK))
2310 goto nla_put_failure;
2311 if (uid_valid(tun->owner) &&
2312 nla_put_u32(skb, IFLA_TUN_OWNER,
2313 from_kuid_munged(current_user_ns(), tun->owner)))
2314 goto nla_put_failure;
2315 if (gid_valid(tun->group) &&
2316 nla_put_u32(skb, IFLA_TUN_GROUP,
2317 from_kgid_munged(current_user_ns(), tun->group)))
2318 goto nla_put_failure;
2319 if (nla_put_u8(skb, IFLA_TUN_PI, !(tun->flags & IFF_NO_PI)))
2320 goto nla_put_failure;
2321 if (nla_put_u8(skb, IFLA_TUN_VNET_HDR, !!(tun->flags & IFF_VNET_HDR)))
2322 goto nla_put_failure;
2323 if (nla_put_u8(skb, IFLA_TUN_PERSIST, !!(tun->flags & IFF_PERSIST)))
2324 goto nla_put_failure;
2325 if (nla_put_u8(skb, IFLA_TUN_MULTI_QUEUE,
2326 !!(tun->flags & IFF_MULTI_QUEUE)))
2327 goto nla_put_failure;
2328 if (tun->flags & IFF_MULTI_QUEUE) {
2329 if (nla_put_u32(skb, IFLA_TUN_NUM_QUEUES, tun->numqueues))
2330 goto nla_put_failure;
2331 if (nla_put_u32(skb, IFLA_TUN_NUM_DISABLED_QUEUES,
2332 tun->numdisabled))
2333 goto nla_put_failure;
2334 }
2335
2336 return 0;
2337
2338 nla_put_failure:
2339 return -EMSGSIZE;
2340 }
2341
2342 static struct rtnl_link_ops tun_link_ops __read_mostly = {
2343 .kind = DRV_NAME,
2344 .priv_size = sizeof(struct tun_struct),
2345 .setup = tun_setup,
2346 .validate = tun_validate,
2347 .get_size = tun_get_size,
2348 .fill_info = tun_fill_info,
2349 };
2350
2351 static void tun_sock_write_space(struct sock *sk)
2352 {
2353 struct tun_file *tfile;
2354 wait_queue_head_t *wqueue;
2355
2356 if (!sock_writeable(sk))
2357 return;
2358
2359 if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
2360 return;
2361
2362 wqueue = sk_sleep(sk);
2363 if (wqueue && waitqueue_active(wqueue))
2364 wake_up_interruptible_sync_poll(wqueue, EPOLLOUT |
2365 EPOLLWRNORM | EPOLLWRBAND);
2366
2367 tfile = container_of(sk, struct tun_file, sk);
2368 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
2369 }
2370
2371 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
2372 {
2373 int ret;
2374 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2375 struct tun_struct *tun = tun_get(tfile);
2376
2377 if (!tun)
2378 return -EBADFD;
2379
2380 ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter,
2381 m->msg_flags & MSG_DONTWAIT,
2382 m->msg_flags & MSG_MORE);
2383 tun_put(tun);
2384 return ret;
2385 }
2386
2387 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
2388 int flags)
2389 {
2390 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2391 struct tun_struct *tun = tun_get(tfile);
2392 void *ptr = m->msg_control;
2393 int ret;
2394
2395 if (!tun) {
2396 ret = -EBADFD;
2397 goto out_free;
2398 }
2399
2400 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
2401 ret = -EINVAL;
2402 goto out_put_tun;
2403 }
2404 if (flags & MSG_ERRQUEUE) {
2405 ret = sock_recv_errqueue(sock->sk, m, total_len,
2406 SOL_PACKET, TUN_TX_TIMESTAMP);
2407 goto out;
2408 }
2409 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT, ptr);
2410 if (ret > (ssize_t)total_len) {
2411 m->msg_flags |= MSG_TRUNC;
2412 ret = flags & MSG_TRUNC ? ret : total_len;
2413 }
2414 out:
2415 tun_put(tun);
2416 return ret;
2417
2418 out_put_tun:
2419 tun_put(tun);
2420 out_free:
2421 tun_ptr_free(ptr);
2422 return ret;
2423 }
2424
2425 static int tun_ptr_peek_len(void *ptr)
2426 {
2427 if (likely(ptr)) {
2428 if (tun_is_xdp_buff(ptr)) {
2429 struct xdp_buff *xdp = tun_ptr_to_xdp(ptr);
2430
2431 return xdp->data_end - xdp->data;
2432 }
2433 return __skb_array_len_with_tag(ptr);
2434 } else {
2435 return 0;
2436 }
2437 }
2438
2439 static int tun_peek_len(struct socket *sock)
2440 {
2441 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2442 struct tun_struct *tun;
2443 int ret = 0;
2444
2445 tun = tun_get(tfile);
2446 if (!tun)
2447 return 0;
2448
2449 ret = PTR_RING_PEEK_CALL(&tfile->tx_ring, tun_ptr_peek_len);
2450 tun_put(tun);
2451
2452 return ret;
2453 }
2454
2455 /* Ops structure to mimic raw sockets with tun */
2456 static const struct proto_ops tun_socket_ops = {
2457 .peek_len = tun_peek_len,
2458 .sendmsg = tun_sendmsg,
2459 .recvmsg = tun_recvmsg,
2460 };
2461
2462 static struct proto tun_proto = {
2463 .name = "tun",
2464 .owner = THIS_MODULE,
2465 .obj_size = sizeof(struct tun_file),
2466 };
2467
2468 static int tun_flags(struct tun_struct *tun)
2469 {
2470 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
2471 }
2472
2473 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
2474 char *buf)
2475 {
2476 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2477 return sprintf(buf, "0x%x\n", tun_flags(tun));
2478 }
2479
2480 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
2481 char *buf)
2482 {
2483 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2484 return uid_valid(tun->owner)?
2485 sprintf(buf, "%u\n",
2486 from_kuid_munged(current_user_ns(), tun->owner)):
2487 sprintf(buf, "-1\n");
2488 }
2489
2490 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
2491 char *buf)
2492 {
2493 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2494 return gid_valid(tun->group) ?
2495 sprintf(buf, "%u\n",
2496 from_kgid_munged(current_user_ns(), tun->group)):
2497 sprintf(buf, "-1\n");
2498 }
2499
2500 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
2501 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
2502 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
2503
2504 static struct attribute *tun_dev_attrs[] = {
2505 &dev_attr_tun_flags.attr,
2506 &dev_attr_owner.attr,
2507 &dev_attr_group.attr,
2508 NULL
2509 };
2510
2511 static const struct attribute_group tun_attr_group = {
2512 .attrs = tun_dev_attrs
2513 };
2514
2515 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
2516 {
2517 struct tun_struct *tun;
2518 struct tun_file *tfile = file->private_data;
2519 struct net_device *dev;
2520 int err;
2521
2522 if (tfile->detached)
2523 return -EINVAL;
2524
2525 if ((ifr->ifr_flags & IFF_NAPI_FRAGS)) {
2526 if (!capable(CAP_NET_ADMIN))
2527 return -EPERM;
2528
2529 if (!(ifr->ifr_flags & IFF_NAPI) ||
2530 (ifr->ifr_flags & TUN_TYPE_MASK) != IFF_TAP)
2531 return -EINVAL;
2532 }
2533
2534 dev = __dev_get_by_name(net, ifr->ifr_name);
2535 if (dev) {
2536 if (ifr->ifr_flags & IFF_TUN_EXCL)
2537 return -EBUSY;
2538 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
2539 tun = netdev_priv(dev);
2540 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
2541 tun = netdev_priv(dev);
2542 else
2543 return -EINVAL;
2544
2545 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
2546 !!(tun->flags & IFF_MULTI_QUEUE))
2547 return -EINVAL;
2548
2549 if (tun_not_capable(tun))
2550 return -EPERM;
2551 err = security_tun_dev_open(tun->security);
2552 if (err < 0)
2553 return err;
2554
2555 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER,
2556 ifr->ifr_flags & IFF_NAPI);
2557 if (err < 0)
2558 return err;
2559
2560 if (tun->flags & IFF_MULTI_QUEUE &&
2561 (tun->numqueues + tun->numdisabled > 1)) {
2562 /* One or more queue has already been attached, no need
2563 * to initialize the device again.
2564 */
2565 return 0;
2566 }
2567 }
2568 else {
2569 char *name;
2570 unsigned long flags = 0;
2571 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
2572 MAX_TAP_QUEUES : 1;
2573
2574 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2575 return -EPERM;
2576 err = security_tun_dev_create();
2577 if (err < 0)
2578 return err;
2579
2580 /* Set dev type */
2581 if (ifr->ifr_flags & IFF_TUN) {
2582 /* TUN device */
2583 flags |= IFF_TUN;
2584 name = "tun%d";
2585 } else if (ifr->ifr_flags & IFF_TAP) {
2586 /* TAP device */
2587 flags |= IFF_TAP;
2588 name = "tap%d";
2589 } else
2590 return -EINVAL;
2591
2592 if (*ifr->ifr_name)
2593 name = ifr->ifr_name;
2594
2595 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
2596 NET_NAME_UNKNOWN, tun_setup, queues,
2597 queues);
2598
2599 if (!dev)
2600 return -ENOMEM;
2601 err = dev_get_valid_name(net, dev, name);
2602 if (err < 0)
2603 goto err_free_dev;
2604
2605 dev_net_set(dev, net);
2606 dev->rtnl_link_ops = &tun_link_ops;
2607 dev->ifindex = tfile->ifindex;
2608 dev->sysfs_groups[0] = &tun_attr_group;
2609
2610 tun = netdev_priv(dev);
2611 tun->dev = dev;
2612 tun->flags = flags;
2613 tun->txflt.count = 0;
2614 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
2615
2616 tun->align = NET_SKB_PAD;
2617 tun->filter_attached = false;
2618 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
2619 tun->rx_batched = 0;
2620 RCU_INIT_POINTER(tun->steering_prog, NULL);
2621
2622 tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats);
2623 if (!tun->pcpu_stats) {
2624 err = -ENOMEM;
2625 goto err_free_dev;
2626 }
2627
2628 spin_lock_init(&tun->lock);
2629
2630 err = security_tun_dev_alloc_security(&tun->security);
2631 if (err < 0)
2632 goto err_free_stat;
2633
2634 tun_net_init(dev);
2635 tun_flow_init(tun);
2636
2637 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
2638 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
2639 NETIF_F_HW_VLAN_STAG_TX;
2640 dev->features = dev->hw_features | NETIF_F_LLTX;
2641 dev->vlan_features = dev->features &
2642 ~(NETIF_F_HW_VLAN_CTAG_TX |
2643 NETIF_F_HW_VLAN_STAG_TX);
2644
2645 INIT_LIST_HEAD(&tun->disabled);
2646 err = tun_attach(tun, file, false, ifr->ifr_flags & IFF_NAPI);
2647 if (err < 0)
2648 goto err_free_flow;
2649
2650 err = register_netdevice(tun->dev);
2651 if (err < 0)
2652 goto err_detach;
2653 }
2654
2655 netif_carrier_on(tun->dev);
2656
2657 tun_debug(KERN_INFO, tun, "tun_set_iff\n");
2658
2659 tun->flags = (tun->flags & ~TUN_FEATURES) |
2660 (ifr->ifr_flags & TUN_FEATURES);
2661
2662 /* Make sure persistent devices do not get stuck in
2663 * xoff state.
2664 */
2665 if (netif_running(tun->dev))
2666 netif_tx_wake_all_queues(tun->dev);
2667
2668 strcpy(ifr->ifr_name, tun->dev->name);
2669 return 0;
2670
2671 err_detach:
2672 tun_detach_all(dev);
2673 /* register_netdevice() already called tun_free_netdev() */
2674 goto err_free_dev;
2675
2676 err_free_flow:
2677 tun_flow_uninit(tun);
2678 security_tun_dev_free_security(tun->security);
2679 err_free_stat:
2680 free_percpu(tun->pcpu_stats);
2681 err_free_dev:
2682 free_netdev(dev);
2683 return err;
2684 }
2685
2686 static void tun_get_iff(struct net *net, struct tun_struct *tun,
2687 struct ifreq *ifr)
2688 {
2689 tun_debug(KERN_INFO, tun, "tun_get_iff\n");
2690
2691 strcpy(ifr->ifr_name, tun->dev->name);
2692
2693 ifr->ifr_flags = tun_flags(tun);
2694
2695 }
2696
2697 /* This is like a cut-down ethtool ops, except done via tun fd so no
2698 * privs required. */
2699 static int set_offload(struct tun_struct *tun, unsigned long arg)
2700 {
2701 netdev_features_t features = 0;
2702
2703 if (arg & TUN_F_CSUM) {
2704 features |= NETIF_F_HW_CSUM;
2705 arg &= ~TUN_F_CSUM;
2706
2707 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
2708 if (arg & TUN_F_TSO_ECN) {
2709 features |= NETIF_F_TSO_ECN;
2710 arg &= ~TUN_F_TSO_ECN;
2711 }
2712 if (arg & TUN_F_TSO4)
2713 features |= NETIF_F_TSO;
2714 if (arg & TUN_F_TSO6)
2715 features |= NETIF_F_TSO6;
2716 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
2717 }
2718
2719 arg &= ~TUN_F_UFO;
2720 }
2721
2722 /* This gives the user a way to test for new features in future by
2723 * trying to set them. */
2724 if (arg)
2725 return -EINVAL;
2726
2727 tun->set_features = features;
2728 tun->dev->wanted_features &= ~TUN_USER_FEATURES;
2729 tun->dev->wanted_features |= features;
2730 netdev_update_features(tun->dev);
2731
2732 return 0;
2733 }
2734
2735 static void tun_detach_filter(struct tun_struct *tun, int n)
2736 {
2737 int i;
2738 struct tun_file *tfile;
2739
2740 for (i = 0; i < n; i++) {
2741 tfile = rtnl_dereference(tun->tfiles[i]);
2742 lock_sock(tfile->socket.sk);
2743 sk_detach_filter(tfile->socket.sk);
2744 release_sock(tfile->socket.sk);
2745 }
2746
2747 tun->filter_attached = false;
2748 }
2749
2750 static int tun_attach_filter(struct tun_struct *tun)
2751 {
2752 int i, ret = 0;
2753 struct tun_file *tfile;
2754
2755 for (i = 0; i < tun->numqueues; i++) {
2756 tfile = rtnl_dereference(tun->tfiles[i]);
2757 lock_sock(tfile->socket.sk);
2758 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
2759 release_sock(tfile->socket.sk);
2760 if (ret) {
2761 tun_detach_filter(tun, i);
2762 return ret;
2763 }
2764 }
2765
2766 tun->filter_attached = true;
2767 return ret;
2768 }
2769
2770 static void tun_set_sndbuf(struct tun_struct *tun)
2771 {
2772 struct tun_file *tfile;
2773 int i;
2774
2775 for (i = 0; i < tun->numqueues; i++) {
2776 tfile = rtnl_dereference(tun->tfiles[i]);
2777 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
2778 }
2779 }
2780
2781 static int tun_set_queue(struct file *file, struct ifreq *ifr)
2782 {
2783 struct tun_file *tfile = file->private_data;
2784 struct tun_struct *tun;
2785 int ret = 0;
2786
2787 rtnl_lock();
2788
2789 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
2790 tun = tfile->detached;
2791 if (!tun) {
2792 ret = -EINVAL;
2793 goto unlock;
2794 }
2795 ret = security_tun_dev_attach_queue(tun->security);
2796 if (ret < 0)
2797 goto unlock;
2798 ret = tun_attach(tun, file, false, tun->flags & IFF_NAPI);
2799 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
2800 tun = rtnl_dereference(tfile->tun);
2801 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
2802 ret = -EINVAL;
2803 else
2804 __tun_detach(tfile, false);
2805 } else
2806 ret = -EINVAL;
2807
2808 unlock:
2809 rtnl_unlock();
2810 return ret;
2811 }
2812
2813 static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog **prog_p,
2814 void __user *data)
2815 {
2816 struct bpf_prog *prog;
2817 int fd;
2818
2819 if (copy_from_user(&fd, data, sizeof(fd)))
2820 return -EFAULT;
2821
2822 if (fd == -1) {
2823 prog = NULL;
2824 } else {
2825 prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
2826 if (IS_ERR(prog))
2827 return PTR_ERR(prog);
2828 }
2829
2830 return __tun_set_ebpf(tun, prog_p, prog);
2831 }
2832
2833 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
2834 unsigned long arg, int ifreq_len)
2835 {
2836 struct tun_file *tfile = file->private_data;
2837 struct tun_struct *tun;
2838 void __user* argp = (void __user*)arg;
2839 struct ifreq ifr;
2840 struct net *net;
2841 kuid_t owner;
2842 kgid_t group;
2843 int sndbuf;
2844 int vnet_hdr_sz;
2845 unsigned int ifindex;
2846 int le;
2847 int ret;
2848
2849 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE ||
2850 (_IOC_TYPE(cmd) == SOCK_IOC_TYPE && cmd != SIOCGSKNS)) {
2851 if (copy_from_user(&ifr, argp, ifreq_len))
2852 return -EFAULT;
2853 } else {
2854 memset(&ifr, 0, sizeof(ifr));
2855 }
2856 if (cmd == TUNGETFEATURES) {
2857 /* Currently this just means: "what IFF flags are valid?".
2858 * This is needed because we never checked for invalid flags on
2859 * TUNSETIFF.
2860 */
2861 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
2862 (unsigned int __user*)argp);
2863 } else if (cmd == TUNSETQUEUE)
2864 return tun_set_queue(file, &ifr);
2865
2866 ret = 0;
2867 rtnl_lock();
2868
2869 tun = tun_get(tfile);
2870 net = sock_net(&tfile->sk);
2871 if (cmd == TUNSETIFF) {
2872 ret = -EEXIST;
2873 if (tun)
2874 goto unlock;
2875
2876 ifr.ifr_name[IFNAMSIZ-1] = '\0';
2877
2878 ret = tun_set_iff(net, file, &ifr);
2879
2880 if (ret)
2881 goto unlock;
2882
2883 if (copy_to_user(argp, &ifr, ifreq_len))
2884 ret = -EFAULT;
2885 goto unlock;
2886 }
2887 if (cmd == TUNSETIFINDEX) {
2888 ret = -EPERM;
2889 if (tun)
2890 goto unlock;
2891
2892 ret = -EFAULT;
2893 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
2894 goto unlock;
2895
2896 ret = 0;
2897 tfile->ifindex = ifindex;
2898 goto unlock;
2899 }
2900 if (cmd == SIOCGSKNS) {
2901 ret = -EPERM;
2902 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2903 goto unlock;
2904
2905 ret = open_related_ns(&net->ns, get_net_ns);
2906 goto unlock;
2907 }
2908
2909 ret = -EBADFD;
2910 if (!tun)
2911 goto unlock;
2912
2913 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
2914
2915 ret = 0;
2916 switch (cmd) {
2917 case TUNGETIFF:
2918 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2919
2920 if (tfile->detached)
2921 ifr.ifr_flags |= IFF_DETACH_QUEUE;
2922 if (!tfile->socket.sk->sk_filter)
2923 ifr.ifr_flags |= IFF_NOFILTER;
2924
2925 if (copy_to_user(argp, &ifr, ifreq_len))
2926 ret = -EFAULT;
2927 break;
2928
2929 case TUNSETNOCSUM:
2930 /* Disable/Enable checksum */
2931
2932 /* [unimplemented] */
2933 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
2934 arg ? "disabled" : "enabled");
2935 break;
2936
2937 case TUNSETPERSIST:
2938 /* Disable/Enable persist mode. Keep an extra reference to the
2939 * module to prevent the module being unprobed.
2940 */
2941 if (arg && !(tun->flags & IFF_PERSIST)) {
2942 tun->flags |= IFF_PERSIST;
2943 __module_get(THIS_MODULE);
2944 }
2945 if (!arg && (tun->flags & IFF_PERSIST)) {
2946 tun->flags &= ~IFF_PERSIST;
2947 module_put(THIS_MODULE);
2948 }
2949
2950 tun_debug(KERN_INFO, tun, "persist %s\n",
2951 arg ? "enabled" : "disabled");
2952 break;
2953
2954 case TUNSETOWNER:
2955 /* Set owner of the device */
2956 owner = make_kuid(current_user_ns(), arg);
2957 if (!uid_valid(owner)) {
2958 ret = -EINVAL;
2959 break;
2960 }
2961 tun->owner = owner;
2962 tun_debug(KERN_INFO, tun, "owner set to %u\n",
2963 from_kuid(&init_user_ns, tun->owner));
2964 break;
2965
2966 case TUNSETGROUP:
2967 /* Set group of the device */
2968 group = make_kgid(current_user_ns(), arg);
2969 if (!gid_valid(group)) {
2970 ret = -EINVAL;
2971 break;
2972 }
2973 tun->group = group;
2974 tun_debug(KERN_INFO, tun, "group set to %u\n",
2975 from_kgid(&init_user_ns, tun->group));
2976 break;
2977
2978 case TUNSETLINK:
2979 /* Only allow setting the type when the interface is down */
2980 if (tun->dev->flags & IFF_UP) {
2981 tun_debug(KERN_INFO, tun,
2982 "Linktype set failed because interface is up\n");
2983 ret = -EBUSY;
2984 } else {
2985 tun->dev->type = (int) arg;
2986 tun_debug(KERN_INFO, tun, "linktype set to %d\n",
2987 tun->dev->type);
2988 ret = 0;
2989 }
2990 break;
2991
2992 #ifdef TUN_DEBUG
2993 case TUNSETDEBUG:
2994 tun->debug = arg;
2995 break;
2996 #endif
2997 case TUNSETOFFLOAD:
2998 ret = set_offload(tun, arg);
2999 break;
3000
3001 case TUNSETTXFILTER:
3002 /* Can be set only for TAPs */
3003 ret = -EINVAL;
3004 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3005 break;
3006 ret = update_filter(&tun->txflt, (void __user *)arg);
3007 break;
3008
3009 case SIOCGIFHWADDR:
3010 /* Get hw address */
3011 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
3012 ifr.ifr_hwaddr.sa_family = tun->dev->type;
3013 if (copy_to_user(argp, &ifr, ifreq_len))
3014 ret = -EFAULT;
3015 break;
3016
3017 case SIOCSIFHWADDR:
3018 /* Set hw address */
3019 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
3020 ifr.ifr_hwaddr.sa_data);
3021
3022 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
3023 break;
3024
3025 case TUNGETSNDBUF:
3026 sndbuf = tfile->socket.sk->sk_sndbuf;
3027 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
3028 ret = -EFAULT;
3029 break;
3030
3031 case TUNSETSNDBUF:
3032 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
3033 ret = -EFAULT;
3034 break;
3035 }
3036 if (sndbuf <= 0) {
3037 ret = -EINVAL;
3038 break;
3039 }
3040
3041 tun->sndbuf = sndbuf;
3042 tun_set_sndbuf(tun);
3043 break;
3044
3045 case TUNGETVNETHDRSZ:
3046 vnet_hdr_sz = tun->vnet_hdr_sz;
3047 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
3048 ret = -EFAULT;
3049 break;
3050
3051 case TUNSETVNETHDRSZ:
3052 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
3053 ret = -EFAULT;
3054 break;
3055 }
3056 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
3057 ret = -EINVAL;
3058 break;
3059 }
3060
3061 tun->vnet_hdr_sz = vnet_hdr_sz;
3062 break;
3063
3064 case TUNGETVNETLE:
3065 le = !!(tun->flags & TUN_VNET_LE);
3066 if (put_user(le, (int __user *)argp))
3067 ret = -EFAULT;
3068 break;
3069
3070 case TUNSETVNETLE:
3071 if (get_user(le, (int __user *)argp)) {
3072 ret = -EFAULT;
3073 break;
3074 }
3075 if (le)
3076 tun->flags |= TUN_VNET_LE;
3077 else
3078 tun->flags &= ~TUN_VNET_LE;
3079 break;
3080
3081 case TUNGETVNETBE:
3082 ret = tun_get_vnet_be(tun, argp);
3083 break;
3084
3085 case TUNSETVNETBE:
3086 ret = tun_set_vnet_be(tun, argp);
3087 break;
3088
3089 case TUNATTACHFILTER:
3090 /* Can be set only for TAPs */
3091 ret = -EINVAL;
3092 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3093 break;
3094 ret = -EFAULT;
3095 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
3096 break;
3097
3098 ret = tun_attach_filter(tun);
3099 break;
3100
3101 case TUNDETACHFILTER:
3102 /* Can be set only for TAPs */
3103 ret = -EINVAL;
3104 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3105 break;
3106 ret = 0;
3107 tun_detach_filter(tun, tun->numqueues);
3108 break;
3109
3110 case TUNGETFILTER:
3111 ret = -EINVAL;
3112 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3113 break;
3114 ret = -EFAULT;
3115 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
3116 break;
3117 ret = 0;
3118 break;
3119
3120 case TUNSETSTEERINGEBPF:
3121 ret = tun_set_ebpf(tun, &tun->steering_prog, argp);
3122 break;
3123
3124 case TUNSETFILTEREBPF:
3125 ret = tun_set_ebpf(tun, &tun->filter_prog, argp);
3126 break;
3127
3128 default:
3129 ret = -EINVAL;
3130 break;
3131 }
3132
3133 unlock:
3134 rtnl_unlock();
3135 if (tun)
3136 tun_put(tun);
3137 return ret;
3138 }
3139
3140 static long tun_chr_ioctl(struct file *file,
3141 unsigned int cmd, unsigned long arg)
3142 {
3143 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
3144 }
3145
3146 #ifdef CONFIG_COMPAT
3147 static long tun_chr_compat_ioctl(struct file *file,
3148 unsigned int cmd, unsigned long arg)
3149 {
3150 switch (cmd) {
3151 case TUNSETIFF:
3152 case TUNGETIFF:
3153 case TUNSETTXFILTER:
3154 case TUNGETSNDBUF:
3155 case TUNSETSNDBUF:
3156 case SIOCGIFHWADDR:
3157 case SIOCSIFHWADDR:
3158 arg = (unsigned long)compat_ptr(arg);
3159 break;
3160 default:
3161 arg = (compat_ulong_t)arg;
3162 break;
3163 }
3164
3165 /*
3166 * compat_ifreq is shorter than ifreq, so we must not access beyond
3167 * the end of that structure. All fields that are used in this
3168 * driver are compatible though, we don't need to convert the
3169 * contents.
3170 */
3171 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
3172 }
3173 #endif /* CONFIG_COMPAT */
3174
3175 static int tun_chr_fasync(int fd, struct file *file, int on)
3176 {
3177 struct tun_file *tfile = file->private_data;
3178 int ret;
3179
3180 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
3181 goto out;
3182
3183 if (on) {
3184 __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
3185 tfile->flags |= TUN_FASYNC;
3186 } else
3187 tfile->flags &= ~TUN_FASYNC;
3188 ret = 0;
3189 out:
3190 return ret;
3191 }
3192
3193 static int tun_chr_open(struct inode *inode, struct file * file)
3194 {
3195 struct net *net = current->nsproxy->net_ns;
3196 struct tun_file *tfile;
3197
3198 DBG1(KERN_INFO, "tunX: tun_chr_open\n");
3199
3200 tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
3201 &tun_proto, 0);
3202 if (!tfile)
3203 return -ENOMEM;
3204 RCU_INIT_POINTER(tfile->tun, NULL);
3205 tfile->flags = 0;
3206 tfile->ifindex = 0;
3207
3208 init_waitqueue_head(&tfile->wq.wait);
3209 RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq);
3210
3211 tfile->socket.file = file;
3212 tfile->socket.ops = &tun_socket_ops;
3213
3214 sock_init_data(&tfile->socket, &tfile->sk);
3215
3216 tfile->sk.sk_write_space = tun_sock_write_space;
3217 tfile->sk.sk_sndbuf = INT_MAX;
3218
3219 file->private_data = tfile;
3220 INIT_LIST_HEAD(&tfile->next);
3221
3222 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
3223
3224 memset(&tfile->tx_ring, 0, sizeof(tfile->tx_ring));
3225
3226 return 0;
3227 }
3228
3229 static int tun_chr_close(struct inode *inode, struct file *file)
3230 {
3231 struct tun_file *tfile = file->private_data;
3232
3233 tun_detach(tfile, true);
3234
3235 return 0;
3236 }
3237
3238 #ifdef CONFIG_PROC_FS
3239 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *file)
3240 {
3241 struct tun_file *tfile = file->private_data;
3242 struct tun_struct *tun;
3243 struct ifreq ifr;
3244
3245 memset(&ifr, 0, sizeof(ifr));
3246
3247 rtnl_lock();
3248 tun = tun_get(tfile);
3249 if (tun)
3250 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
3251 rtnl_unlock();
3252
3253 if (tun)
3254 tun_put(tun);
3255
3256 seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
3257 }
3258 #endif
3259
3260 static const struct file_operations tun_fops = {
3261 .owner = THIS_MODULE,
3262 .llseek = no_llseek,
3263 .read_iter = tun_chr_read_iter,
3264 .write_iter = tun_chr_write_iter,
3265 .poll = tun_chr_poll,
3266 .unlocked_ioctl = tun_chr_ioctl,
3267 #ifdef CONFIG_COMPAT
3268 .compat_ioctl = tun_chr_compat_ioctl,
3269 #endif
3270 .open = tun_chr_open,
3271 .release = tun_chr_close,
3272 .fasync = tun_chr_fasync,
3273 #ifdef CONFIG_PROC_FS
3274 .show_fdinfo = tun_chr_show_fdinfo,
3275 #endif
3276 };
3277
3278 static struct miscdevice tun_miscdev = {
3279 .minor = TUN_MINOR,
3280 .name = "tun",
3281 .nodename = "net/tun",
3282 .fops = &tun_fops,
3283 };
3284
3285 /* ethtool interface */
3286
3287 static int tun_get_link_ksettings(struct net_device *dev,
3288 struct ethtool_link_ksettings *cmd)
3289 {
3290 ethtool_link_ksettings_zero_link_mode(cmd, supported);
3291 ethtool_link_ksettings_zero_link_mode(cmd, advertising);
3292 cmd->base.speed = SPEED_10;
3293 cmd->base.duplex = DUPLEX_FULL;
3294 cmd->base.port = PORT_TP;
3295 cmd->base.phy_address = 0;
3296 cmd->base.autoneg = AUTONEG_DISABLE;
3297 return 0;
3298 }
3299
3300 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
3301 {
3302 struct tun_struct *tun = netdev_priv(dev);
3303
3304 strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
3305 strlcpy(info->version, DRV_VERSION, sizeof(info->version));
3306
3307 switch (tun->flags & TUN_TYPE_MASK) {
3308 case IFF_TUN:
3309 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
3310 break;
3311 case IFF_TAP:
3312 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
3313 break;
3314 }
3315 }
3316
3317 static u32 tun_get_msglevel(struct net_device *dev)
3318 {
3319 #ifdef TUN_DEBUG
3320 struct tun_struct *tun = netdev_priv(dev);
3321 return tun->debug;
3322 #else
3323 return -EOPNOTSUPP;
3324 #endif
3325 }
3326
3327 static void tun_set_msglevel(struct net_device *dev, u32 value)
3328 {
3329 #ifdef TUN_DEBUG
3330 struct tun_struct *tun = netdev_priv(dev);
3331 tun->debug = value;
3332 #endif
3333 }
3334
3335 static int tun_get_coalesce(struct net_device *dev,
3336 struct ethtool_coalesce *ec)
3337 {
3338 struct tun_struct *tun = netdev_priv(dev);
3339
3340 ec->rx_max_coalesced_frames = tun->rx_batched;
3341
3342 return 0;
3343 }
3344
3345 static int tun_set_coalesce(struct net_device *dev,
3346 struct ethtool_coalesce *ec)
3347 {
3348 struct tun_struct *tun = netdev_priv(dev);
3349
3350 if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT)
3351 tun->rx_batched = NAPI_POLL_WEIGHT;
3352 else
3353 tun->rx_batched = ec->rx_max_coalesced_frames;
3354
3355 return 0;
3356 }
3357
3358 static const struct ethtool_ops tun_ethtool_ops = {
3359 .get_drvinfo = tun_get_drvinfo,
3360 .get_msglevel = tun_get_msglevel,
3361 .set_msglevel = tun_set_msglevel,
3362 .get_link = ethtool_op_get_link,
3363 .get_ts_info = ethtool_op_get_ts_info,
3364 .get_coalesce = tun_get_coalesce,
3365 .set_coalesce = tun_set_coalesce,
3366 .get_link_ksettings = tun_get_link_ksettings,
3367 };
3368
3369 static int tun_queue_resize(struct tun_struct *tun)
3370 {
3371 struct net_device *dev = tun->dev;
3372 struct tun_file *tfile;
3373 struct ptr_ring **rings;
3374 int n = tun->numqueues + tun->numdisabled;
3375 int ret, i;
3376
3377 rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL);
3378 if (!rings)
3379 return -ENOMEM;
3380
3381 for (i = 0; i < tun->numqueues; i++) {
3382 tfile = rtnl_dereference(tun->tfiles[i]);
3383 rings[i] = &tfile->tx_ring;
3384 }
3385 list_for_each_entry(tfile, &tun->disabled, next)
3386 rings[i++] = &tfile->tx_ring;
3387
3388 ret = ptr_ring_resize_multiple(rings, n,
3389 dev->tx_queue_len, GFP_KERNEL,
3390 tun_ptr_free);
3391
3392 kfree(rings);
3393 return ret;
3394 }
3395
3396 static int tun_device_event(struct notifier_block *unused,
3397 unsigned long event, void *ptr)
3398 {
3399 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3400 struct tun_struct *tun = netdev_priv(dev);
3401
3402 if (dev->rtnl_link_ops != &tun_link_ops)
3403 return NOTIFY_DONE;
3404
3405 switch (event) {
3406 case NETDEV_CHANGE_TX_QUEUE_LEN:
3407 if (tun_queue_resize(tun))
3408 return NOTIFY_BAD;
3409 break;
3410 default:
3411 break;
3412 }
3413
3414 return NOTIFY_DONE;
3415 }
3416
3417 static struct notifier_block tun_notifier_block __read_mostly = {
3418 .notifier_call = tun_device_event,
3419 };
3420
3421 static int __init tun_init(void)
3422 {
3423 int ret = 0;
3424
3425 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
3426
3427 ret = rtnl_link_register(&tun_link_ops);
3428 if (ret) {
3429 pr_err("Can't register link_ops\n");
3430 goto err_linkops;
3431 }
3432
3433 ret = misc_register(&tun_miscdev);
3434 if (ret) {
3435 pr_err("Can't register misc device %d\n", TUN_MINOR);
3436 goto err_misc;
3437 }
3438
3439 ret = register_netdevice_notifier(&tun_notifier_block);
3440 if (ret) {
3441 pr_err("Can't register netdevice notifier\n");
3442 goto err_notifier;
3443 }
3444
3445 return 0;
3446
3447 err_notifier:
3448 misc_deregister(&tun_miscdev);
3449 err_misc:
3450 rtnl_link_unregister(&tun_link_ops);
3451 err_linkops:
3452 return ret;
3453 }
3454
3455 static void tun_cleanup(void)
3456 {
3457 misc_deregister(&tun_miscdev);
3458 rtnl_link_unregister(&tun_link_ops);
3459 unregister_netdevice_notifier(&tun_notifier_block);
3460 }
3461
3462 /* Get an underlying socket object from tun file. Returns error unless file is
3463 * attached to a device. The returned object works like a packet socket, it
3464 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
3465 * holding a reference to the file for as long as the socket is in use. */
3466 struct socket *tun_get_socket(struct file *file)
3467 {
3468 struct tun_file *tfile;
3469 if (file->f_op != &tun_fops)
3470 return ERR_PTR(-EINVAL);
3471 tfile = file->private_data;
3472 if (!tfile)
3473 return ERR_PTR(-EBADFD);
3474 return &tfile->socket;
3475 }
3476 EXPORT_SYMBOL_GPL(tun_get_socket);
3477
3478 struct ptr_ring *tun_get_tx_ring(struct file *file)
3479 {
3480 struct tun_file *tfile;
3481
3482 if (file->f_op != &tun_fops)
3483 return ERR_PTR(-EINVAL);
3484 tfile = file->private_data;
3485 if (!tfile)
3486 return ERR_PTR(-EBADFD);
3487 return &tfile->tx_ring;
3488 }
3489 EXPORT_SYMBOL_GPL(tun_get_tx_ring);
3490
3491 module_init(tun_init);
3492 module_exit(tun_cleanup);
3493 MODULE_DESCRIPTION(DRV_DESCRIPTION);
3494 MODULE_AUTHOR(DRV_COPYRIGHT);
3495 MODULE_LICENSE("GPL");
3496 MODULE_ALIAS_MISCDEV(TUN_MINOR);
3497 MODULE_ALIAS("devname:net/tun");
Linux with added FPC-III support