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gpio: rcar: Fix runtime PM imbalance on error
[linux/fpc-iii.git] / drivers / net / tun.c
blob07476c6510f2f50f8185b2be401a5894e37350c8
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * TUN - Universal TUN/TAP device driver.
4 * Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com>
5 *
6 * $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
7 */
8
9 /*
10 * Changes:
11 *
12 * Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
13 * Add TUNSETLINK ioctl to set the link encapsulation
14 *
15 * Mark Smith <markzzzsmith@yahoo.com.au>
16 * Use eth_random_addr() for tap MAC address.
17 *
18 * Harald Roelle <harald.roelle@ifi.lmu.de> 2004/04/20
19 * Fixes in packet dropping, queue length setting and queue wakeup.
20 * Increased default tx queue length.
21 * Added ethtool API.
22 * Minor cleanups
23 *
24 * Daniel Podlejski <underley@underley.eu.org>
25 * Modifications for 2.3.99-pre5 kernel.
26 */
27
28 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
29
30 #define DRV_NAME "tun"
31 #define DRV_VERSION "1.6"
32 #define DRV_DESCRIPTION "Universal TUN/TAP device driver"
33 #define DRV_COPYRIGHT "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
34
35 #include <linux/module.h>
36 #include <linux/errno.h>
37 #include <linux/kernel.h>
38 #include <linux/sched/signal.h>
39 #include <linux/major.h>
40 #include <linux/slab.h>
41 #include <linux/poll.h>
42 #include <linux/fcntl.h>
43 #include <linux/init.h>
44 #include <linux/skbuff.h>
45 #include <linux/netdevice.h>
46 #include <linux/etherdevice.h>
47 #include <linux/miscdevice.h>
48 #include <linux/ethtool.h>
49 #include <linux/rtnetlink.h>
50 #include <linux/compat.h>
51 #include <linux/if.h>
52 #include <linux/if_arp.h>
53 #include <linux/if_ether.h>
54 #include <linux/if_tun.h>
55 #include <linux/if_vlan.h>
56 #include <linux/crc32.h>
57 #include <linux/nsproxy.h>
58 #include <linux/virtio_net.h>
59 #include <linux/rcupdate.h>
60 #include <net/net_namespace.h>
61 #include <net/netns/generic.h>
62 #include <net/rtnetlink.h>
63 #include <net/sock.h>
64 #include <net/xdp.h>
65 #include <linux/seq_file.h>
66 #include <linux/uio.h>
67 #include <linux/skb_array.h>
68 #include <linux/bpf.h>
69 #include <linux/bpf_trace.h>
70 #include <linux/mutex.h>
71
72 #include <linux/uaccess.h>
73 #include <linux/proc_fs.h>
74
75 static void tun_default_link_ksettings(struct net_device *dev,
76 struct ethtool_link_ksettings *cmd);
77
78 #define TUN_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
79
80 /* TUN device flags */
81
82 /* IFF_ATTACH_QUEUE is never stored in device flags,
83 * overload it to mean fasync when stored there.
84 */
85 #define TUN_FASYNC IFF_ATTACH_QUEUE
86 /* High bits in flags field are unused. */
87 #define TUN_VNET_LE 0x80000000
88 #define TUN_VNET_BE 0x40000000
89
90 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
91 IFF_MULTI_QUEUE | IFF_NAPI | IFF_NAPI_FRAGS)
92
93 #define GOODCOPY_LEN 128
94
95 #define FLT_EXACT_COUNT 8
96 struct tap_filter {
97 unsigned int count; /* Number of addrs. Zero means disabled */
98 u32 mask[2]; /* Mask of the hashed addrs */
99 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
100 };
101
102 /* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
103 * to max number of VCPUs in guest. */
104 #define MAX_TAP_QUEUES 256
105 #define MAX_TAP_FLOWS 4096
106
107 #define TUN_FLOW_EXPIRE (3 * HZ)
108
109 struct tun_pcpu_stats {
110 u64_stats_t rx_packets;
111 u64_stats_t rx_bytes;
112 u64_stats_t tx_packets;
113 u64_stats_t tx_bytes;
114 struct u64_stats_sync syncp;
115 u32 rx_dropped;
116 u32 tx_dropped;
117 u32 rx_frame_errors;
118 };
119
120 /* A tun_file connects an open character device to a tuntap netdevice. It
121 * also contains all socket related structures (except sock_fprog and tap_filter)
122 * to serve as one transmit queue for tuntap device. The sock_fprog and
123 * tap_filter were kept in tun_struct since they were used for filtering for the
124 * netdevice not for a specific queue (at least I didn't see the requirement for
125 * this).
126 *
127 * RCU usage:
128 * The tun_file and tun_struct are loosely coupled, the pointer from one to the
129 * other can only be read while rcu_read_lock or rtnl_lock is held.
130 */
131 struct tun_file {
132 struct sock sk;
133 struct socket socket;
134 struct tun_struct __rcu *tun;
135 struct fasync_struct *fasync;
136 /* only used for fasnyc */
137 unsigned int flags;
138 union {
139 u16 queue_index;
140 unsigned int ifindex;
141 };
142 struct napi_struct napi;
143 bool napi_enabled;
144 bool napi_frags_enabled;
145 struct mutex napi_mutex; /* Protects access to the above napi */
146 struct list_head next;
147 struct tun_struct *detached;
148 struct ptr_ring tx_ring;
149 struct xdp_rxq_info xdp_rxq;
150 };
151
152 struct tun_page {
153 struct page *page;
154 int count;
155 };
156
157 struct tun_flow_entry {
158 struct hlist_node hash_link;
159 struct rcu_head rcu;
160 struct tun_struct *tun;
161
162 u32 rxhash;
163 u32 rps_rxhash;
164 int queue_index;
165 unsigned long updated ____cacheline_aligned_in_smp;
166 };
167
168 #define TUN_NUM_FLOW_ENTRIES 1024
169 #define TUN_MASK_FLOW_ENTRIES (TUN_NUM_FLOW_ENTRIES - 1)
170
171 struct tun_prog {
172 struct rcu_head rcu;
173 struct bpf_prog *prog;
174 };
175
176 /* Since the socket were moved to tun_file, to preserve the behavior of persist
177 * device, socket filter, sndbuf and vnet header size were restore when the
178 * file were attached to a persist device.
179 */
180 struct tun_struct {
181 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES];
182 unsigned int numqueues;
183 unsigned int flags;
184 kuid_t owner;
185 kgid_t group;
186
187 struct net_device *dev;
188 netdev_features_t set_features;
189 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
190 NETIF_F_TSO6)
191
192 int align;
193 int vnet_hdr_sz;
194 int sndbuf;
195 struct tap_filter txflt;
196 struct sock_fprog fprog;
197 /* protected by rtnl lock */
198 bool filter_attached;
199 u32 msg_enable;
200 spinlock_t lock;
201 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
202 struct timer_list flow_gc_timer;
203 unsigned long ageing_time;
204 unsigned int numdisabled;
205 struct list_head disabled;
206 void *security;
207 u32 flow_count;
208 u32 rx_batched;
209 struct tun_pcpu_stats __percpu *pcpu_stats;
210 struct bpf_prog __rcu *xdp_prog;
211 struct tun_prog __rcu *steering_prog;
212 struct tun_prog __rcu *filter_prog;
213 struct ethtool_link_ksettings link_ksettings;
214 };
215
216 struct veth {
217 __be16 h_vlan_proto;
218 __be16 h_vlan_TCI;
219 };
220
221 bool tun_is_xdp_frame(void *ptr)
222 {
223 return (unsigned long)ptr & TUN_XDP_FLAG;
224 }
225 EXPORT_SYMBOL(tun_is_xdp_frame);
226
227 void *tun_xdp_to_ptr(void *ptr)
228 {
229 return (void *)((unsigned long)ptr | TUN_XDP_FLAG);
230 }
231 EXPORT_SYMBOL(tun_xdp_to_ptr);
232
233 void *tun_ptr_to_xdp(void *ptr)
234 {
235 return (void *)((unsigned long)ptr & ~TUN_XDP_FLAG);
236 }
237 EXPORT_SYMBOL(tun_ptr_to_xdp);
238
239 static int tun_napi_receive(struct napi_struct *napi, int budget)
240 {
241 struct tun_file *tfile = container_of(napi, struct tun_file, napi);
242 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
243 struct sk_buff_head process_queue;
244 struct sk_buff *skb;
245 int received = 0;
246
247 __skb_queue_head_init(&process_queue);
248
249 spin_lock(&queue->lock);
250 skb_queue_splice_tail_init(queue, &process_queue);
251 spin_unlock(&queue->lock);
252
253 while (received < budget && (skb = __skb_dequeue(&process_queue))) {
254 napi_gro_receive(napi, skb);
255 ++received;
256 }
257
258 if (!skb_queue_empty(&process_queue)) {
259 spin_lock(&queue->lock);
260 skb_queue_splice(&process_queue, queue);
261 spin_unlock(&queue->lock);
262 }
263
264 return received;
265 }
266
267 static int tun_napi_poll(struct napi_struct *napi, int budget)
268 {
269 unsigned int received;
270
271 received = tun_napi_receive(napi, budget);
272
273 if (received < budget)
274 napi_complete_done(napi, received);
275
276 return received;
277 }
278
279 static void tun_napi_init(struct tun_struct *tun, struct tun_file *tfile,
280 bool napi_en, bool napi_frags)
281 {
282 tfile->napi_enabled = napi_en;
283 tfile->napi_frags_enabled = napi_en && napi_frags;
284 if (napi_en) {
285 netif_tx_napi_add(tun->dev, &tfile->napi, tun_napi_poll,
286 NAPI_POLL_WEIGHT);
287 napi_enable(&tfile->napi);
288 }
289 }
290
291 static void tun_napi_disable(struct tun_file *tfile)
292 {
293 if (tfile->napi_enabled)
294 napi_disable(&tfile->napi);
295 }
296
297 static void tun_napi_del(struct tun_file *tfile)
298 {
299 if (tfile->napi_enabled)
300 netif_napi_del(&tfile->napi);
301 }
302
303 static bool tun_napi_frags_enabled(const struct tun_file *tfile)
304 {
305 return tfile->napi_frags_enabled;
306 }
307
308 #ifdef CONFIG_TUN_VNET_CROSS_LE
309 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
310 {
311 return tun->flags & TUN_VNET_BE ? false :
312 virtio_legacy_is_little_endian();
313 }
314
315 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
316 {
317 int be = !!(tun->flags & TUN_VNET_BE);
318
319 if (put_user(be, argp))
320 return -EFAULT;
321
322 return 0;
323 }
324
325 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
326 {
327 int be;
328
329 if (get_user(be, argp))
330 return -EFAULT;
331
332 if (be)
333 tun->flags |= TUN_VNET_BE;
334 else
335 tun->flags &= ~TUN_VNET_BE;
336
337 return 0;
338 }
339 #else
340 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
341 {
342 return virtio_legacy_is_little_endian();
343 }
344
345 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
346 {
347 return -EINVAL;
348 }
349
350 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
351 {
352 return -EINVAL;
353 }
354 #endif /* CONFIG_TUN_VNET_CROSS_LE */
355
356 static inline bool tun_is_little_endian(struct tun_struct *tun)
357 {
358 return tun->flags & TUN_VNET_LE ||
359 tun_legacy_is_little_endian(tun);
360 }
361
362 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
363 {
364 return __virtio16_to_cpu(tun_is_little_endian(tun), val);
365 }
366
367 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
368 {
369 return __cpu_to_virtio16(tun_is_little_endian(tun), val);
370 }
371
372 static inline u32 tun_hashfn(u32 rxhash)
373 {
374 return rxhash & TUN_MASK_FLOW_ENTRIES;
375 }
376
377 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
378 {
379 struct tun_flow_entry *e;
380
381 hlist_for_each_entry_rcu(e, head, hash_link) {
382 if (e->rxhash == rxhash)
383 return e;
384 }
385 return NULL;
386 }
387
388 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
389 struct hlist_head *head,
390 u32 rxhash, u16 queue_index)
391 {
392 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
393
394 if (e) {
395 netif_info(tun, tx_queued, tun->dev,
396 "create flow: hash %u index %u\n",
397 rxhash, queue_index);
398 e->updated = jiffies;
399 e->rxhash = rxhash;
400 e->rps_rxhash = 0;
401 e->queue_index = queue_index;
402 e->tun = tun;
403 hlist_add_head_rcu(&e->hash_link, head);
404 ++tun->flow_count;
405 }
406 return e;
407 }
408
409 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
410 {
411 netif_info(tun, tx_queued, tun->dev, "delete flow: hash %u index %u\n",
412 e->rxhash, e->queue_index);
413 hlist_del_rcu(&e->hash_link);
414 kfree_rcu(e, rcu);
415 --tun->flow_count;
416 }
417
418 static void tun_flow_flush(struct tun_struct *tun)
419 {
420 int i;
421
422 spin_lock_bh(&tun->lock);
423 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
424 struct tun_flow_entry *e;
425 struct hlist_node *n;
426
427 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
428 tun_flow_delete(tun, e);
429 }
430 spin_unlock_bh(&tun->lock);
431 }
432
433 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
434 {
435 int i;
436
437 spin_lock_bh(&tun->lock);
438 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
439 struct tun_flow_entry *e;
440 struct hlist_node *n;
441
442 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
443 if (e->queue_index == queue_index)
444 tun_flow_delete(tun, e);
445 }
446 }
447 spin_unlock_bh(&tun->lock);
448 }
449
450 static void tun_flow_cleanup(struct timer_list *t)
451 {
452 struct tun_struct *tun = from_timer(tun, t, flow_gc_timer);
453 unsigned long delay = tun->ageing_time;
454 unsigned long next_timer = jiffies + delay;
455 unsigned long count = 0;
456 int i;
457
458 spin_lock(&tun->lock);
459 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
460 struct tun_flow_entry *e;
461 struct hlist_node *n;
462
463 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
464 unsigned long this_timer;
465
466 this_timer = e->updated + delay;
467 if (time_before_eq(this_timer, jiffies)) {
468 tun_flow_delete(tun, e);
469 continue;
470 }
471 count++;
472 if (time_before(this_timer, next_timer))
473 next_timer = this_timer;
474 }
475 }
476
477 if (count)
478 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
479 spin_unlock(&tun->lock);
480 }
481
482 static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
483 struct tun_file *tfile)
484 {
485 struct hlist_head *head;
486 struct tun_flow_entry *e;
487 unsigned long delay = tun->ageing_time;
488 u16 queue_index = tfile->queue_index;
489
490 head = &tun->flows[tun_hashfn(rxhash)];
491
492 rcu_read_lock();
493
494 e = tun_flow_find(head, rxhash);
495 if (likely(e)) {
496 /* TODO: keep queueing to old queue until it's empty? */
497 if (READ_ONCE(e->queue_index) != queue_index)
498 WRITE_ONCE(e->queue_index, queue_index);
499 if (e->updated != jiffies)
500 e->updated = jiffies;
501 sock_rps_record_flow_hash(e->rps_rxhash);
502 } else {
503 spin_lock_bh(&tun->lock);
504 if (!tun_flow_find(head, rxhash) &&
505 tun->flow_count < MAX_TAP_FLOWS)
506 tun_flow_create(tun, head, rxhash, queue_index);
507
508 if (!timer_pending(&tun->flow_gc_timer))
509 mod_timer(&tun->flow_gc_timer,
510 round_jiffies_up(jiffies + delay));
511 spin_unlock_bh(&tun->lock);
512 }
513
514 rcu_read_unlock();
515 }
516
517 /* Save the hash received in the stack receive path and update the
518 * flow_hash table accordingly.
519 */
520 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
521 {
522 if (unlikely(e->rps_rxhash != hash))
523 e->rps_rxhash = hash;
524 }
525
526 /* We try to identify a flow through its rxhash. The reason that
527 * we do not check rxq no. is because some cards(e.g 82599), chooses
528 * the rxq based on the txq where the last packet of the flow comes. As
529 * the userspace application move between processors, we may get a
530 * different rxq no. here.
531 */
532 static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb)
533 {
534 struct tun_flow_entry *e;
535 u32 txq = 0;
536 u32 numqueues = 0;
537
538 numqueues = READ_ONCE(tun->numqueues);
539
540 txq = __skb_get_hash_symmetric(skb);
541 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
542 if (e) {
543 tun_flow_save_rps_rxhash(e, txq);
544 txq = e->queue_index;
545 } else {
546 /* use multiply and shift instead of expensive divide */
547 txq = ((u64)txq * numqueues) >> 32;
548 }
549
550 return txq;
551 }
552
553 static u16 tun_ebpf_select_queue(struct tun_struct *tun, struct sk_buff *skb)
554 {
555 struct tun_prog *prog;
556 u32 numqueues;
557 u16 ret = 0;
558
559 numqueues = READ_ONCE(tun->numqueues);
560 if (!numqueues)
561 return 0;
562
563 prog = rcu_dereference(tun->steering_prog);
564 if (prog)
565 ret = bpf_prog_run_clear_cb(prog->prog, skb);
566
567 return ret % numqueues;
568 }
569
570 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
571 struct net_device *sb_dev)
572 {
573 struct tun_struct *tun = netdev_priv(dev);
574 u16 ret;
575
576 rcu_read_lock();
577 if (rcu_dereference(tun->steering_prog))
578 ret = tun_ebpf_select_queue(tun, skb);
579 else
580 ret = tun_automq_select_queue(tun, skb);
581 rcu_read_unlock();
582
583 return ret;
584 }
585
586 static inline bool tun_not_capable(struct tun_struct *tun)
587 {
588 const struct cred *cred = current_cred();
589 struct net *net = dev_net(tun->dev);
590
591 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
592 (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
593 !ns_capable(net->user_ns, CAP_NET_ADMIN);
594 }
595
596 static void tun_set_real_num_queues(struct tun_struct *tun)
597 {
598 netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
599 netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
600 }
601
602 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
603 {
604 tfile->detached = tun;
605 list_add_tail(&tfile->next, &tun->disabled);
606 ++tun->numdisabled;
607 }
608
609 static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
610 {
611 struct tun_struct *tun = tfile->detached;
612
613 tfile->detached = NULL;
614 list_del_init(&tfile->next);
615 --tun->numdisabled;
616 return tun;
617 }
618
619 void tun_ptr_free(void *ptr)
620 {
621 if (!ptr)
622 return;
623 if (tun_is_xdp_frame(ptr)) {
624 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
625
626 xdp_return_frame(xdpf);
627 } else {
628 __skb_array_destroy_skb(ptr);
629 }
630 }
631 EXPORT_SYMBOL_GPL(tun_ptr_free);
632
633 static void tun_queue_purge(struct tun_file *tfile)
634 {
635 void *ptr;
636
637 while ((ptr = ptr_ring_consume(&tfile->tx_ring)) != NULL)
638 tun_ptr_free(ptr);
639
640 skb_queue_purge(&tfile->sk.sk_write_queue);
641 skb_queue_purge(&tfile->sk.sk_error_queue);
642 }
643
644 static void __tun_detach(struct tun_file *tfile, bool clean)
645 {
646 struct tun_file *ntfile;
647 struct tun_struct *tun;
648
649 tun = rtnl_dereference(tfile->tun);
650
651 if (tun && clean) {
652 tun_napi_disable(tfile);
653 tun_napi_del(tfile);
654 }
655
656 if (tun && !tfile->detached) {
657 u16 index = tfile->queue_index;
658 BUG_ON(index >= tun->numqueues);
659
660 rcu_assign_pointer(tun->tfiles[index],
661 tun->tfiles[tun->numqueues - 1]);
662 ntfile = rtnl_dereference(tun->tfiles[index]);
663 ntfile->queue_index = index;
664 rcu_assign_pointer(tun->tfiles[tun->numqueues - 1],
665 NULL);
666
667 --tun->numqueues;
668 if (clean) {
669 RCU_INIT_POINTER(tfile->tun, NULL);
670 sock_put(&tfile->sk);
671 } else
672 tun_disable_queue(tun, tfile);
673
674 synchronize_net();
675 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
676 /* Drop read queue */
677 tun_queue_purge(tfile);
678 tun_set_real_num_queues(tun);
679 } else if (tfile->detached && clean) {
680 tun = tun_enable_queue(tfile);
681 sock_put(&tfile->sk);
682 }
683
684 if (clean) {
685 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
686 netif_carrier_off(tun->dev);
687
688 if (!(tun->flags & IFF_PERSIST) &&
689 tun->dev->reg_state == NETREG_REGISTERED)
690 unregister_netdevice(tun->dev);
691 }
692 if (tun)
693 xdp_rxq_info_unreg(&tfile->xdp_rxq);
694 ptr_ring_cleanup(&tfile->tx_ring, tun_ptr_free);
695 sock_put(&tfile->sk);
696 }
697 }
698
699 static void tun_detach(struct tun_file *tfile, bool clean)
700 {
701 struct tun_struct *tun;
702 struct net_device *dev;
703
704 rtnl_lock();
705 tun = rtnl_dereference(tfile->tun);
706 dev = tun ? tun->dev : NULL;
707 __tun_detach(tfile, clean);
708 if (dev)
709 netdev_state_change(dev);
710 rtnl_unlock();
711 }
712
713 static void tun_detach_all(struct net_device *dev)
714 {
715 struct tun_struct *tun = netdev_priv(dev);
716 struct tun_file *tfile, *tmp;
717 int i, n = tun->numqueues;
718
719 for (i = 0; i < n; i++) {
720 tfile = rtnl_dereference(tun->tfiles[i]);
721 BUG_ON(!tfile);
722 tun_napi_disable(tfile);
723 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
724 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
725 RCU_INIT_POINTER(tfile->tun, NULL);
726 --tun->numqueues;
727 }
728 list_for_each_entry(tfile, &tun->disabled, next) {
729 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
730 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
731 RCU_INIT_POINTER(tfile->tun, NULL);
732 }
733 BUG_ON(tun->numqueues != 0);
734
735 synchronize_net();
736 for (i = 0; i < n; i++) {
737 tfile = rtnl_dereference(tun->tfiles[i]);
738 tun_napi_del(tfile);
739 /* Drop read queue */
740 tun_queue_purge(tfile);
741 xdp_rxq_info_unreg(&tfile->xdp_rxq);
742 sock_put(&tfile->sk);
743 }
744 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
745 tun_enable_queue(tfile);
746 tun_queue_purge(tfile);
747 xdp_rxq_info_unreg(&tfile->xdp_rxq);
748 sock_put(&tfile->sk);
749 }
750 BUG_ON(tun->numdisabled != 0);
751
752 if (tun->flags & IFF_PERSIST)
753 module_put(THIS_MODULE);
754 }
755
756 static int tun_attach(struct tun_struct *tun, struct file *file,
757 bool skip_filter, bool napi, bool napi_frags,
758 bool publish_tun)
759 {
760 struct tun_file *tfile = file->private_data;
761 struct net_device *dev = tun->dev;
762 int err;
763
764 err = security_tun_dev_attach(tfile->socket.sk, tun->security);
765 if (err < 0)
766 goto out;
767
768 err = -EINVAL;
769 if (rtnl_dereference(tfile->tun) && !tfile->detached)
770 goto out;
771
772 err = -EBUSY;
773 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
774 goto out;
775
776 err = -E2BIG;
777 if (!tfile->detached &&
778 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
779 goto out;
780
781 err = 0;
782
783 /* Re-attach the filter to persist device */
784 if (!skip_filter && (tun->filter_attached == true)) {
785 lock_sock(tfile->socket.sk);
786 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
787 release_sock(tfile->socket.sk);
788 if (!err)
789 goto out;
790 }
791
792 if (!tfile->detached &&
793 ptr_ring_resize(&tfile->tx_ring, dev->tx_queue_len,
794 GFP_KERNEL, tun_ptr_free)) {
795 err = -ENOMEM;
796 goto out;
797 }
798
799 tfile->queue_index = tun->numqueues;
800 tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
801
802 if (tfile->detached) {
803 /* Re-attach detached tfile, updating XDP queue_index */
804 WARN_ON(!xdp_rxq_info_is_reg(&tfile->xdp_rxq));
805
806 if (tfile->xdp_rxq.queue_index != tfile->queue_index)
807 tfile->xdp_rxq.queue_index = tfile->queue_index;
808 } else {
809 /* Setup XDP RX-queue info, for new tfile getting attached */
810 err = xdp_rxq_info_reg(&tfile->xdp_rxq,
811 tun->dev, tfile->queue_index);
812 if (err < 0)
813 goto out;
814 err = xdp_rxq_info_reg_mem_model(&tfile->xdp_rxq,
815 MEM_TYPE_PAGE_SHARED, NULL);
816 if (err < 0) {
817 xdp_rxq_info_unreg(&tfile->xdp_rxq);
818 goto out;
819 }
820 err = 0;
821 }
822
823 if (tfile->detached) {
824 tun_enable_queue(tfile);
825 } else {
826 sock_hold(&tfile->sk);
827 tun_napi_init(tun, tfile, napi, napi_frags);
828 }
829
830 if (rtnl_dereference(tun->xdp_prog))
831 sock_set_flag(&tfile->sk, SOCK_XDP);
832
833 /* device is allowed to go away first, so no need to hold extra
834 * refcnt.
835 */
836
837 /* Publish tfile->tun and tun->tfiles only after we've fully
838 * initialized tfile; otherwise we risk using half-initialized
839 * object.
840 */
841 if (publish_tun)
842 rcu_assign_pointer(tfile->tun, tun);
843 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
844 tun->numqueues++;
845 tun_set_real_num_queues(tun);
846 out:
847 return err;
848 }
849
850 static struct tun_struct *tun_get(struct tun_file *tfile)
851 {
852 struct tun_struct *tun;
853
854 rcu_read_lock();
855 tun = rcu_dereference(tfile->tun);
856 if (tun)
857 dev_hold(tun->dev);
858 rcu_read_unlock();
859
860 return tun;
861 }
862
863 static void tun_put(struct tun_struct *tun)
864 {
865 dev_put(tun->dev);
866 }
867
868 /* TAP filtering */
869 static void addr_hash_set(u32 *mask, const u8 *addr)
870 {
871 int n = ether_crc(ETH_ALEN, addr) >> 26;
872 mask[n >> 5] |= (1 << (n & 31));
873 }
874
875 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
876 {
877 int n = ether_crc(ETH_ALEN, addr) >> 26;
878 return mask[n >> 5] & (1 << (n & 31));
879 }
880
881 static int update_filter(struct tap_filter *filter, void __user *arg)
882 {
883 struct { u8 u[ETH_ALEN]; } *addr;
884 struct tun_filter uf;
885 int err, alen, n, nexact;
886
887 if (copy_from_user(&uf, arg, sizeof(uf)))
888 return -EFAULT;
889
890 if (!uf.count) {
891 /* Disabled */
892 filter->count = 0;
893 return 0;
894 }
895
896 alen = ETH_ALEN * uf.count;
897 addr = memdup_user(arg + sizeof(uf), alen);
898 if (IS_ERR(addr))
899 return PTR_ERR(addr);
900
901 /* The filter is updated without holding any locks. Which is
902 * perfectly safe. We disable it first and in the worst
903 * case we'll accept a few undesired packets. */
904 filter->count = 0;
905 wmb();
906
907 /* Use first set of addresses as an exact filter */
908 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
909 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
910
911 nexact = n;
912
913 /* Remaining multicast addresses are hashed,
914 * unicast will leave the filter disabled. */
915 memset(filter->mask, 0, sizeof(filter->mask));
916 for (; n < uf.count; n++) {
917 if (!is_multicast_ether_addr(addr[n].u)) {
918 err = 0; /* no filter */
919 goto free_addr;
920 }
921 addr_hash_set(filter->mask, addr[n].u);
922 }
923
924 /* For ALLMULTI just set the mask to all ones.
925 * This overrides the mask populated above. */
926 if ((uf.flags & TUN_FLT_ALLMULTI))
927 memset(filter->mask, ~0, sizeof(filter->mask));
928
929 /* Now enable the filter */
930 wmb();
931 filter->count = nexact;
932
933 /* Return the number of exact filters */
934 err = nexact;
935 free_addr:
936 kfree(addr);
937 return err;
938 }
939
940 /* Returns: 0 - drop, !=0 - accept */
941 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
942 {
943 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
944 * at this point. */
945 struct ethhdr *eh = (struct ethhdr *) skb->data;
946 int i;
947
948 /* Exact match */
949 for (i = 0; i < filter->count; i++)
950 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
951 return 1;
952
953 /* Inexact match (multicast only) */
954 if (is_multicast_ether_addr(eh->h_dest))
955 return addr_hash_test(filter->mask, eh->h_dest);
956
957 return 0;
958 }
959
960 /*
961 * Checks whether the packet is accepted or not.
962 * Returns: 0 - drop, !=0 - accept
963 */
964 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
965 {
966 if (!filter->count)
967 return 1;
968
969 return run_filter(filter, skb);
970 }
971
972 /* Network device part of the driver */
973
974 static const struct ethtool_ops tun_ethtool_ops;
975
976 /* Net device detach from fd. */
977 static void tun_net_uninit(struct net_device *dev)
978 {
979 tun_detach_all(dev);
980 }
981
982 /* Net device open. */
983 static int tun_net_open(struct net_device *dev)
984 {
985 netif_tx_start_all_queues(dev);
986
987 return 0;
988 }
989
990 /* Net device close. */
991 static int tun_net_close(struct net_device *dev)
992 {
993 netif_tx_stop_all_queues(dev);
994 return 0;
995 }
996
997 /* Net device start xmit */
998 static void tun_automq_xmit(struct tun_struct *tun, struct sk_buff *skb)
999 {
1000 #ifdef CONFIG_RPS
1001 if (tun->numqueues == 1 && static_branch_unlikely(&rps_needed)) {
1002 /* Select queue was not called for the skbuff, so we extract the
1003 * RPS hash and save it into the flow_table here.
1004 */
1005 struct tun_flow_entry *e;
1006 __u32 rxhash;
1007
1008 rxhash = __skb_get_hash_symmetric(skb);
1009 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)], rxhash);
1010 if (e)
1011 tun_flow_save_rps_rxhash(e, rxhash);
1012 }
1013 #endif
1014 }
1015
1016 static unsigned int run_ebpf_filter(struct tun_struct *tun,
1017 struct sk_buff *skb,
1018 int len)
1019 {
1020 struct tun_prog *prog = rcu_dereference(tun->filter_prog);
1021
1022 if (prog)
1023 len = bpf_prog_run_clear_cb(prog->prog, skb);
1024
1025 return len;
1026 }
1027
1028 /* Net device start xmit */
1029 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
1030 {
1031 struct tun_struct *tun = netdev_priv(dev);
1032 int txq = skb->queue_mapping;
1033 struct tun_file *tfile;
1034 int len = skb->len;
1035
1036 rcu_read_lock();
1037 tfile = rcu_dereference(tun->tfiles[txq]);
1038
1039 /* Drop packet if interface is not attached */
1040 if (!tfile)
1041 goto drop;
1042
1043 if (!rcu_dereference(tun->steering_prog))
1044 tun_automq_xmit(tun, skb);
1045
1046 netif_info(tun, tx_queued, tun->dev, "%s %d\n", __func__, skb->len);
1047
1048 /* Drop if the filter does not like it.
1049 * This is a noop if the filter is disabled.
1050 * Filter can be enabled only for the TAP devices. */
1051 if (!check_filter(&tun->txflt, skb))
1052 goto drop;
1053
1054 if (tfile->socket.sk->sk_filter &&
1055 sk_filter(tfile->socket.sk, skb))
1056 goto drop;
1057
1058 len = run_ebpf_filter(tun, skb, len);
1059 if (len == 0 || pskb_trim(skb, len))
1060 goto drop;
1061
1062 if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC)))
1063 goto drop;
1064
1065 skb_tx_timestamp(skb);
1066
1067 /* Orphan the skb - required as we might hang on to it
1068 * for indefinite time.
1069 */
1070 skb_orphan(skb);
1071
1072 nf_reset_ct(skb);
1073
1074 if (ptr_ring_produce(&tfile->tx_ring, skb))
1075 goto drop;
1076
1077 /* Notify and wake up reader process */
1078 if (tfile->flags & TUN_FASYNC)
1079 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1080 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1081
1082 rcu_read_unlock();
1083 return NETDEV_TX_OK;
1084
1085 drop:
1086 this_cpu_inc(tun->pcpu_stats->tx_dropped);
1087 skb_tx_error(skb);
1088 kfree_skb(skb);
1089 rcu_read_unlock();
1090 return NET_XMIT_DROP;
1091 }
1092
1093 static void tun_net_mclist(struct net_device *dev)
1094 {
1095 /*
1096 * This callback is supposed to deal with mc filter in
1097 * _rx_ path and has nothing to do with the _tx_ path.
1098 * In rx path we always accept everything userspace gives us.
1099 */
1100 }
1101
1102 static netdev_features_t tun_net_fix_features(struct net_device *dev,
1103 netdev_features_t features)
1104 {
1105 struct tun_struct *tun = netdev_priv(dev);
1106
1107 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
1108 }
1109
1110 static void tun_set_headroom(struct net_device *dev, int new_hr)
1111 {
1112 struct tun_struct *tun = netdev_priv(dev);
1113
1114 if (new_hr < NET_SKB_PAD)
1115 new_hr = NET_SKB_PAD;
1116
1117 tun->align = new_hr;
1118 }
1119
1120 static void
1121 tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
1122 {
1123 u32 rx_dropped = 0, tx_dropped = 0, rx_frame_errors = 0;
1124 struct tun_struct *tun = netdev_priv(dev);
1125 struct tun_pcpu_stats *p;
1126 int i;
1127
1128 for_each_possible_cpu(i) {
1129 u64 rxpackets, rxbytes, txpackets, txbytes;
1130 unsigned int start;
1131
1132 p = per_cpu_ptr(tun->pcpu_stats, i);
1133 do {
1134 start = u64_stats_fetch_begin(&p->syncp);
1135 rxpackets = u64_stats_read(&p->rx_packets);
1136 rxbytes = u64_stats_read(&p->rx_bytes);
1137 txpackets = u64_stats_read(&p->tx_packets);
1138 txbytes = u64_stats_read(&p->tx_bytes);
1139 } while (u64_stats_fetch_retry(&p->syncp, start));
1140
1141 stats->rx_packets += rxpackets;
1142 stats->rx_bytes += rxbytes;
1143 stats->tx_packets += txpackets;
1144 stats->tx_bytes += txbytes;
1145
1146 /* u32 counters */
1147 rx_dropped += p->rx_dropped;
1148 rx_frame_errors += p->rx_frame_errors;
1149 tx_dropped += p->tx_dropped;
1150 }
1151 stats->rx_dropped = rx_dropped;
1152 stats->rx_frame_errors = rx_frame_errors;
1153 stats->tx_dropped = tx_dropped;
1154 }
1155
1156 static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1157 struct netlink_ext_ack *extack)
1158 {
1159 struct tun_struct *tun = netdev_priv(dev);
1160 struct tun_file *tfile;
1161 struct bpf_prog *old_prog;
1162 int i;
1163
1164 old_prog = rtnl_dereference(tun->xdp_prog);
1165 rcu_assign_pointer(tun->xdp_prog, prog);
1166 if (old_prog)
1167 bpf_prog_put(old_prog);
1168
1169 for (i = 0; i < tun->numqueues; i++) {
1170 tfile = rtnl_dereference(tun->tfiles[i]);
1171 if (prog)
1172 sock_set_flag(&tfile->sk, SOCK_XDP);
1173 else
1174 sock_reset_flag(&tfile->sk, SOCK_XDP);
1175 }
1176 list_for_each_entry(tfile, &tun->disabled, next) {
1177 if (prog)
1178 sock_set_flag(&tfile->sk, SOCK_XDP);
1179 else
1180 sock_reset_flag(&tfile->sk, SOCK_XDP);
1181 }
1182
1183 return 0;
1184 }
1185
1186 static u32 tun_xdp_query(struct net_device *dev)
1187 {
1188 struct tun_struct *tun = netdev_priv(dev);
1189 const struct bpf_prog *xdp_prog;
1190
1191 xdp_prog = rtnl_dereference(tun->xdp_prog);
1192 if (xdp_prog)
1193 return xdp_prog->aux->id;
1194
1195 return 0;
1196 }
1197
1198 static int tun_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1199 {
1200 switch (xdp->command) {
1201 case XDP_SETUP_PROG:
1202 return tun_xdp_set(dev, xdp->prog, xdp->extack);
1203 case XDP_QUERY_PROG:
1204 xdp->prog_id = tun_xdp_query(dev);
1205 return 0;
1206 default:
1207 return -EINVAL;
1208 }
1209 }
1210
1211 static int tun_net_change_carrier(struct net_device *dev, bool new_carrier)
1212 {
1213 if (new_carrier) {
1214 struct tun_struct *tun = netdev_priv(dev);
1215
1216 if (!tun->numqueues)
1217 return -EPERM;
1218
1219 netif_carrier_on(dev);
1220 } else {
1221 netif_carrier_off(dev);
1222 }
1223 return 0;
1224 }
1225
1226 static const struct net_device_ops tun_netdev_ops = {
1227 .ndo_uninit = tun_net_uninit,
1228 .ndo_open = tun_net_open,
1229 .ndo_stop = tun_net_close,
1230 .ndo_start_xmit = tun_net_xmit,
1231 .ndo_fix_features = tun_net_fix_features,
1232 .ndo_select_queue = tun_select_queue,
1233 .ndo_set_rx_headroom = tun_set_headroom,
1234 .ndo_get_stats64 = tun_net_get_stats64,
1235 .ndo_change_carrier = tun_net_change_carrier,
1236 };
1237
1238 static void __tun_xdp_flush_tfile(struct tun_file *tfile)
1239 {
1240 /* Notify and wake up reader process */
1241 if (tfile->flags & TUN_FASYNC)
1242 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1243 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1244 }
1245
1246 static int tun_xdp_xmit(struct net_device *dev, int n,
1247 struct xdp_frame **frames, u32 flags)
1248 {
1249 struct tun_struct *tun = netdev_priv(dev);
1250 struct tun_file *tfile;
1251 u32 numqueues;
1252 int drops = 0;
1253 int cnt = n;
1254 int i;
1255
1256 if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
1257 return -EINVAL;
1258
1259 rcu_read_lock();
1260
1261 resample:
1262 numqueues = READ_ONCE(tun->numqueues);
1263 if (!numqueues) {
1264 rcu_read_unlock();
1265 return -ENXIO; /* Caller will free/return all frames */
1266 }
1267
1268 tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
1269 numqueues]);
1270 if (unlikely(!tfile))
1271 goto resample;
1272
1273 spin_lock(&tfile->tx_ring.producer_lock);
1274 for (i = 0; i < n; i++) {
1275 struct xdp_frame *xdp = frames[i];
1276 /* Encode the XDP flag into lowest bit for consumer to differ
1277 * XDP buffer from sk_buff.
1278 */
1279 void *frame = tun_xdp_to_ptr(xdp);
1280
1281 if (__ptr_ring_produce(&tfile->tx_ring, frame)) {
1282 this_cpu_inc(tun->pcpu_stats->tx_dropped);
1283 xdp_return_frame_rx_napi(xdp);
1284 drops++;
1285 }
1286 }
1287 spin_unlock(&tfile->tx_ring.producer_lock);
1288
1289 if (flags & XDP_XMIT_FLUSH)
1290 __tun_xdp_flush_tfile(tfile);
1291
1292 rcu_read_unlock();
1293 return cnt - drops;
1294 }
1295
1296 static int tun_xdp_tx(struct net_device *dev, struct xdp_buff *xdp)
1297 {
1298 struct xdp_frame *frame = convert_to_xdp_frame(xdp);
1299
1300 if (unlikely(!frame))
1301 return -EOVERFLOW;
1302
1303 return tun_xdp_xmit(dev, 1, &frame, XDP_XMIT_FLUSH);
1304 }
1305
1306 static const struct net_device_ops tap_netdev_ops = {
1307 .ndo_uninit = tun_net_uninit,
1308 .ndo_open = tun_net_open,
1309 .ndo_stop = tun_net_close,
1310 .ndo_start_xmit = tun_net_xmit,
1311 .ndo_fix_features = tun_net_fix_features,
1312 .ndo_set_rx_mode = tun_net_mclist,
1313 .ndo_set_mac_address = eth_mac_addr,
1314 .ndo_validate_addr = eth_validate_addr,
1315 .ndo_select_queue = tun_select_queue,
1316 .ndo_features_check = passthru_features_check,
1317 .ndo_set_rx_headroom = tun_set_headroom,
1318 .ndo_get_stats64 = tun_net_get_stats64,
1319 .ndo_bpf = tun_xdp,
1320 .ndo_xdp_xmit = tun_xdp_xmit,
1321 .ndo_change_carrier = tun_net_change_carrier,
1322 };
1323
1324 static void tun_flow_init(struct tun_struct *tun)
1325 {
1326 int i;
1327
1328 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1329 INIT_HLIST_HEAD(&tun->flows[i]);
1330
1331 tun->ageing_time = TUN_FLOW_EXPIRE;
1332 timer_setup(&tun->flow_gc_timer, tun_flow_cleanup, 0);
1333 mod_timer(&tun->flow_gc_timer,
1334 round_jiffies_up(jiffies + tun->ageing_time));
1335 }
1336
1337 static void tun_flow_uninit(struct tun_struct *tun)
1338 {
1339 del_timer_sync(&tun->flow_gc_timer);
1340 tun_flow_flush(tun);
1341 }
1342
1343 #define MIN_MTU 68
1344 #define MAX_MTU 65535
1345
1346 /* Initialize net device. */
1347 static void tun_net_init(struct net_device *dev)
1348 {
1349 struct tun_struct *tun = netdev_priv(dev);
1350
1351 switch (tun->flags & TUN_TYPE_MASK) {
1352 case IFF_TUN:
1353 dev->netdev_ops = &tun_netdev_ops;
1354
1355 /* Point-to-Point TUN Device */
1356 dev->hard_header_len = 0;
1357 dev->addr_len = 0;
1358 dev->mtu = 1500;
1359
1360 /* Zero header length */
1361 dev->type = ARPHRD_NONE;
1362 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1363 break;
1364
1365 case IFF_TAP:
1366 dev->netdev_ops = &tap_netdev_ops;
1367 /* Ethernet TAP Device */
1368 ether_setup(dev);
1369 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1370 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1371
1372 eth_hw_addr_random(dev);
1373
1374 break;
1375 }
1376
1377 dev->min_mtu = MIN_MTU;
1378 dev->max_mtu = MAX_MTU - dev->hard_header_len;
1379 }
1380
1381 static bool tun_sock_writeable(struct tun_struct *tun, struct tun_file *tfile)
1382 {
1383 struct sock *sk = tfile->socket.sk;
1384
1385 return (tun->dev->flags & IFF_UP) && sock_writeable(sk);
1386 }
1387
1388 /* Character device part */
1389
1390 /* Poll */
1391 static __poll_t tun_chr_poll(struct file *file, poll_table *wait)
1392 {
1393 struct tun_file *tfile = file->private_data;
1394 struct tun_struct *tun = tun_get(tfile);
1395 struct sock *sk;
1396 __poll_t mask = 0;
1397
1398 if (!tun)
1399 return EPOLLERR;
1400
1401 sk = tfile->socket.sk;
1402
1403 poll_wait(file, sk_sleep(sk), wait);
1404
1405 if (!ptr_ring_empty(&tfile->tx_ring))
1406 mask |= EPOLLIN | EPOLLRDNORM;
1407
1408 /* Make sure SOCKWQ_ASYNC_NOSPACE is set if not writable to
1409 * guarantee EPOLLOUT to be raised by either here or
1410 * tun_sock_write_space(). Then process could get notification
1411 * after it writes to a down device and meets -EIO.
1412 */
1413 if (tun_sock_writeable(tun, tfile) ||
1414 (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1415 tun_sock_writeable(tun, tfile)))
1416 mask |= EPOLLOUT | EPOLLWRNORM;
1417
1418 if (tun->dev->reg_state != NETREG_REGISTERED)
1419 mask = EPOLLERR;
1420
1421 tun_put(tun);
1422 return mask;
1423 }
1424
1425 static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile,
1426 size_t len,
1427 const struct iov_iter *it)
1428 {
1429 struct sk_buff *skb;
1430 size_t linear;
1431 int err;
1432 int i;
1433
1434 if (it->nr_segs > MAX_SKB_FRAGS + 1)
1435 return ERR_PTR(-ENOMEM);
1436
1437 local_bh_disable();
1438 skb = napi_get_frags(&tfile->napi);
1439 local_bh_enable();
1440 if (!skb)
1441 return ERR_PTR(-ENOMEM);
1442
1443 linear = iov_iter_single_seg_count(it);
1444 err = __skb_grow(skb, linear);
1445 if (err)
1446 goto free;
1447
1448 skb->len = len;
1449 skb->data_len = len - linear;
1450 skb->truesize += skb->data_len;
1451
1452 for (i = 1; i < it->nr_segs; i++) {
1453 size_t fragsz = it->iov[i].iov_len;
1454 struct page *page;
1455 void *frag;
1456
1457 if (fragsz == 0 || fragsz > PAGE_SIZE) {
1458 err = -EINVAL;
1459 goto free;
1460 }
1461 frag = netdev_alloc_frag(fragsz);
1462 if (!frag) {
1463 err = -ENOMEM;
1464 goto free;
1465 }
1466 page = virt_to_head_page(frag);
1467 skb_fill_page_desc(skb, i - 1, page,
1468 frag - page_address(page), fragsz);
1469 }
1470
1471 return skb;
1472 free:
1473 /* frees skb and all frags allocated with napi_alloc_frag() */
1474 napi_free_frags(&tfile->napi);
1475 return ERR_PTR(err);
1476 }
1477
1478 /* prepad is the amount to reserve at front. len is length after that.
1479 * linear is a hint as to how much to copy (usually headers). */
1480 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1481 size_t prepad, size_t len,
1482 size_t linear, int noblock)
1483 {
1484 struct sock *sk = tfile->socket.sk;
1485 struct sk_buff *skb;
1486 int err;
1487
1488 /* Under a page? Don't bother with paged skb. */
1489 if (prepad + len < PAGE_SIZE || !linear)
1490 linear = len;
1491
1492 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1493 &err, 0);
1494 if (!skb)
1495 return ERR_PTR(err);
1496
1497 skb_reserve(skb, prepad);
1498 skb_put(skb, linear);
1499 skb->data_len = len - linear;
1500 skb->len += len - linear;
1501
1502 return skb;
1503 }
1504
1505 static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile,
1506 struct sk_buff *skb, int more)
1507 {
1508 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1509 struct sk_buff_head process_queue;
1510 u32 rx_batched = tun->rx_batched;
1511 bool rcv = false;
1512
1513 if (!rx_batched || (!more && skb_queue_empty(queue))) {
1514 local_bh_disable();
1515 skb_record_rx_queue(skb, tfile->queue_index);
1516 netif_receive_skb(skb);
1517 local_bh_enable();
1518 return;
1519 }
1520
1521 spin_lock(&queue->lock);
1522 if (!more || skb_queue_len(queue) == rx_batched) {
1523 __skb_queue_head_init(&process_queue);
1524 skb_queue_splice_tail_init(queue, &process_queue);
1525 rcv = true;
1526 } else {
1527 __skb_queue_tail(queue, skb);
1528 }
1529 spin_unlock(&queue->lock);
1530
1531 if (rcv) {
1532 struct sk_buff *nskb;
1533
1534 local_bh_disable();
1535 while ((nskb = __skb_dequeue(&process_queue))) {
1536 skb_record_rx_queue(nskb, tfile->queue_index);
1537 netif_receive_skb(nskb);
1538 }
1539 skb_record_rx_queue(skb, tfile->queue_index);
1540 netif_receive_skb(skb);
1541 local_bh_enable();
1542 }
1543 }
1544
1545 static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile,
1546 int len, int noblock, bool zerocopy)
1547 {
1548 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
1549 return false;
1550
1551 if (tfile->socket.sk->sk_sndbuf != INT_MAX)
1552 return false;
1553
1554 if (!noblock)
1555 return false;
1556
1557 if (zerocopy)
1558 return false;
1559
1560 if (SKB_DATA_ALIGN(len + TUN_RX_PAD) +
1561 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
1562 return false;
1563
1564 return true;
1565 }
1566
1567 static struct sk_buff *__tun_build_skb(struct tun_file *tfile,
1568 struct page_frag *alloc_frag, char *buf,
1569 int buflen, int len, int pad)
1570 {
1571 struct sk_buff *skb = build_skb(buf, buflen);
1572
1573 if (!skb)
1574 return ERR_PTR(-ENOMEM);
1575
1576 skb_reserve(skb, pad);
1577 skb_put(skb, len);
1578 skb_set_owner_w(skb, tfile->socket.sk);
1579
1580 get_page(alloc_frag->page);
1581 alloc_frag->offset += buflen;
1582
1583 return skb;
1584 }
1585
1586 static int tun_xdp_act(struct tun_struct *tun, struct bpf_prog *xdp_prog,
1587 struct xdp_buff *xdp, u32 act)
1588 {
1589 int err;
1590
1591 switch (act) {
1592 case XDP_REDIRECT:
1593 err = xdp_do_redirect(tun->dev, xdp, xdp_prog);
1594 if (err)
1595 return err;
1596 break;
1597 case XDP_TX:
1598 err = tun_xdp_tx(tun->dev, xdp);
1599 if (err < 0)
1600 return err;
1601 break;
1602 case XDP_PASS:
1603 break;
1604 default:
1605 bpf_warn_invalid_xdp_action(act);
1606 /* fall through */
1607 case XDP_ABORTED:
1608 trace_xdp_exception(tun->dev, xdp_prog, act);
1609 /* fall through */
1610 case XDP_DROP:
1611 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1612 break;
1613 }
1614
1615 return act;
1616 }
1617
1618 static struct sk_buff *tun_build_skb(struct tun_struct *tun,
1619 struct tun_file *tfile,
1620 struct iov_iter *from,
1621 struct virtio_net_hdr *hdr,
1622 int len, int *skb_xdp)
1623 {
1624 struct page_frag *alloc_frag = &current->task_frag;
1625 struct bpf_prog *xdp_prog;
1626 int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1627 char *buf;
1628 size_t copied;
1629 int pad = TUN_RX_PAD;
1630 int err = 0;
1631
1632 rcu_read_lock();
1633 xdp_prog = rcu_dereference(tun->xdp_prog);
1634 if (xdp_prog)
1635 pad += XDP_PACKET_HEADROOM;
1636 buflen += SKB_DATA_ALIGN(len + pad);
1637 rcu_read_unlock();
1638
1639 alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES);
1640 if (unlikely(!skb_page_frag_refill(buflen, alloc_frag, GFP_KERNEL)))
1641 return ERR_PTR(-ENOMEM);
1642
1643 buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
1644 copied = copy_page_from_iter(alloc_frag->page,
1645 alloc_frag->offset + pad,
1646 len, from);
1647 if (copied != len)
1648 return ERR_PTR(-EFAULT);
1649
1650 /* There's a small window that XDP may be set after the check
1651 * of xdp_prog above, this should be rare and for simplicity
1652 * we do XDP on skb in case the headroom is not enough.
1653 */
1654 if (hdr->gso_type || !xdp_prog) {
1655 *skb_xdp = 1;
1656 return __tun_build_skb(tfile, alloc_frag, buf, buflen, len,
1657 pad);
1658 }
1659
1660 *skb_xdp = 0;
1661
1662 local_bh_disable();
1663 rcu_read_lock();
1664 xdp_prog = rcu_dereference(tun->xdp_prog);
1665 if (xdp_prog) {
1666 struct xdp_buff xdp;
1667 u32 act;
1668
1669 xdp.data_hard_start = buf;
1670 xdp.data = buf + pad;
1671 xdp_set_data_meta_invalid(&xdp);
1672 xdp.data_end = xdp.data + len;
1673 xdp.rxq = &tfile->xdp_rxq;
1674
1675 act = bpf_prog_run_xdp(xdp_prog, &xdp);
1676 if (act == XDP_REDIRECT || act == XDP_TX) {
1677 get_page(alloc_frag->page);
1678 alloc_frag->offset += buflen;
1679 }
1680 err = tun_xdp_act(tun, xdp_prog, &xdp, act);
1681 if (err < 0) {
1682 if (act == XDP_REDIRECT || act == XDP_TX)
1683 put_page(alloc_frag->page);
1684 goto out;
1685 }
1686
1687 if (err == XDP_REDIRECT)
1688 xdp_do_flush();
1689 if (err != XDP_PASS)
1690 goto out;
1691
1692 pad = xdp.data - xdp.data_hard_start;
1693 len = xdp.data_end - xdp.data;
1694 }
1695 rcu_read_unlock();
1696 local_bh_enable();
1697
1698 return __tun_build_skb(tfile, alloc_frag, buf, buflen, len, pad);
1699
1700 out:
1701 rcu_read_unlock();
1702 local_bh_enable();
1703 return NULL;
1704 }
1705
1706 /* Get packet from user space buffer */
1707 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1708 void *msg_control, struct iov_iter *from,
1709 int noblock, bool more)
1710 {
1711 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1712 struct sk_buff *skb;
1713 size_t total_len = iov_iter_count(from);
1714 size_t len = total_len, align = tun->align, linear;
1715 struct virtio_net_hdr gso = { 0 };
1716 struct tun_pcpu_stats *stats;
1717 int good_linear;
1718 int copylen;
1719 bool zerocopy = false;
1720 int err;
1721 u32 rxhash = 0;
1722 int skb_xdp = 1;
1723 bool frags = tun_napi_frags_enabled(tfile);
1724
1725 if (!(tun->flags & IFF_NO_PI)) {
1726 if (len < sizeof(pi))
1727 return -EINVAL;
1728 len -= sizeof(pi);
1729
1730 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1731 return -EFAULT;
1732 }
1733
1734 if (tun->flags & IFF_VNET_HDR) {
1735 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1736
1737 if (len < vnet_hdr_sz)
1738 return -EINVAL;
1739 len -= vnet_hdr_sz;
1740
1741 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1742 return -EFAULT;
1743
1744 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1745 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1746 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1747
1748 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1749 return -EINVAL;
1750 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1751 }
1752
1753 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1754 align += NET_IP_ALIGN;
1755 if (unlikely(len < ETH_HLEN ||
1756 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1757 return -EINVAL;
1758 }
1759
1760 good_linear = SKB_MAX_HEAD(align);
1761
1762 if (msg_control) {
1763 struct iov_iter i = *from;
1764
1765 /* There are 256 bytes to be copied in skb, so there is
1766 * enough room for skb expand head in case it is used.
1767 * The rest of the buffer is mapped from userspace.
1768 */
1769 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1770 if (copylen > good_linear)
1771 copylen = good_linear;
1772 linear = copylen;
1773 iov_iter_advance(&i, copylen);
1774 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1775 zerocopy = true;
1776 }
1777
1778 if (!frags && tun_can_build_skb(tun, tfile, len, noblock, zerocopy)) {
1779 /* For the packet that is not easy to be processed
1780 * (e.g gso or jumbo packet), we will do it at after
1781 * skb was created with generic XDP routine.
1782 */
1783 skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp);
1784 if (IS_ERR(skb)) {
1785 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1786 return PTR_ERR(skb);
1787 }
1788 if (!skb)
1789 return total_len;
1790 } else {
1791 if (!zerocopy) {
1792 copylen = len;
1793 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1794 linear = good_linear;
1795 else
1796 linear = tun16_to_cpu(tun, gso.hdr_len);
1797 }
1798
1799 if (frags) {
1800 mutex_lock(&tfile->napi_mutex);
1801 skb = tun_napi_alloc_frags(tfile, copylen, from);
1802 /* tun_napi_alloc_frags() enforces a layout for the skb.
1803 * If zerocopy is enabled, then this layout will be
1804 * overwritten by zerocopy_sg_from_iter().
1805 */
1806 zerocopy = false;
1807 } else {
1808 skb = tun_alloc_skb(tfile, align, copylen, linear,
1809 noblock);
1810 }
1811
1812 if (IS_ERR(skb)) {
1813 if (PTR_ERR(skb) != -EAGAIN)
1814 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1815 if (frags)
1816 mutex_unlock(&tfile->napi_mutex);
1817 return PTR_ERR(skb);
1818 }
1819
1820 if (zerocopy)
1821 err = zerocopy_sg_from_iter(skb, from);
1822 else
1823 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1824
1825 if (err) {
1826 err = -EFAULT;
1827 drop:
1828 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1829 kfree_skb(skb);
1830 if (frags) {
1831 tfile->napi.skb = NULL;
1832 mutex_unlock(&tfile->napi_mutex);
1833 }
1834
1835 return err;
1836 }
1837 }
1838
1839 if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1840 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
1841 kfree_skb(skb);
1842 if (frags) {
1843 tfile->napi.skb = NULL;
1844 mutex_unlock(&tfile->napi_mutex);
1845 }
1846
1847 return -EINVAL;
1848 }
1849
1850 switch (tun->flags & TUN_TYPE_MASK) {
1851 case IFF_TUN:
1852 if (tun->flags & IFF_NO_PI) {
1853 u8 ip_version = skb->len ? (skb->data[0] >> 4) : 0;
1854
1855 switch (ip_version) {
1856 case 4:
1857 pi.proto = htons(ETH_P_IP);
1858 break;
1859 case 6:
1860 pi.proto = htons(ETH_P_IPV6);
1861 break;
1862 default:
1863 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1864 kfree_skb(skb);
1865 return -EINVAL;
1866 }
1867 }
1868
1869 skb_reset_mac_header(skb);
1870 skb->protocol = pi.proto;
1871 skb->dev = tun->dev;
1872 break;
1873 case IFF_TAP:
1874 if (!frags)
1875 skb->protocol = eth_type_trans(skb, tun->dev);
1876 break;
1877 }
1878
1879 /* copy skb_ubuf_info for callback when skb has no error */
1880 if (zerocopy) {
1881 skb_shinfo(skb)->destructor_arg = msg_control;
1882 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1883 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1884 } else if (msg_control) {
1885 struct ubuf_info *uarg = msg_control;
1886 uarg->callback(uarg, false);
1887 }
1888
1889 skb_reset_network_header(skb);
1890 skb_probe_transport_header(skb);
1891
1892 if (skb_xdp) {
1893 struct bpf_prog *xdp_prog;
1894 int ret;
1895
1896 local_bh_disable();
1897 rcu_read_lock();
1898 xdp_prog = rcu_dereference(tun->xdp_prog);
1899 if (xdp_prog) {
1900 ret = do_xdp_generic(xdp_prog, skb);
1901 if (ret != XDP_PASS) {
1902 rcu_read_unlock();
1903 local_bh_enable();
1904 if (frags) {
1905 tfile->napi.skb = NULL;
1906 mutex_unlock(&tfile->napi_mutex);
1907 }
1908 return total_len;
1909 }
1910 }
1911 rcu_read_unlock();
1912 local_bh_enable();
1913 }
1914
1915 /* Compute the costly rx hash only if needed for flow updates.
1916 * We may get a very small possibility of OOO during switching, not
1917 * worth to optimize.
1918 */
1919 if (!rcu_access_pointer(tun->steering_prog) && tun->numqueues > 1 &&
1920 !tfile->detached)
1921 rxhash = __skb_get_hash_symmetric(skb);
1922
1923 rcu_read_lock();
1924 if (unlikely(!(tun->dev->flags & IFF_UP))) {
1925 err = -EIO;
1926 rcu_read_unlock();
1927 goto drop;
1928 }
1929
1930 if (frags) {
1931 /* Exercise flow dissector code path. */
1932 u32 headlen = eth_get_headlen(tun->dev, skb->data,
1933 skb_headlen(skb));
1934
1935 if (unlikely(headlen > skb_headlen(skb))) {
1936 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1937 napi_free_frags(&tfile->napi);
1938 rcu_read_unlock();
1939 mutex_unlock(&tfile->napi_mutex);
1940 WARN_ON(1);
1941 return -ENOMEM;
1942 }
1943
1944 local_bh_disable();
1945 napi_gro_frags(&tfile->napi);
1946 local_bh_enable();
1947 mutex_unlock(&tfile->napi_mutex);
1948 } else if (tfile->napi_enabled) {
1949 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1950 int queue_len;
1951
1952 spin_lock_bh(&queue->lock);
1953 __skb_queue_tail(queue, skb);
1954 queue_len = skb_queue_len(queue);
1955 spin_unlock(&queue->lock);
1956
1957 if (!more || queue_len > NAPI_POLL_WEIGHT)
1958 napi_schedule(&tfile->napi);
1959
1960 local_bh_enable();
1961 } else if (!IS_ENABLED(CONFIG_4KSTACKS)) {
1962 tun_rx_batched(tun, tfile, skb, more);
1963 } else {
1964 netif_rx_ni(skb);
1965 }
1966 rcu_read_unlock();
1967
1968 stats = get_cpu_ptr(tun->pcpu_stats);
1969 u64_stats_update_begin(&stats->syncp);
1970 u64_stats_inc(&stats->rx_packets);
1971 u64_stats_add(&stats->rx_bytes, len);
1972 u64_stats_update_end(&stats->syncp);
1973 put_cpu_ptr(stats);
1974
1975 if (rxhash)
1976 tun_flow_update(tun, rxhash, tfile);
1977
1978 return total_len;
1979 }
1980
1981 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
1982 {
1983 struct file *file = iocb->ki_filp;
1984 struct tun_file *tfile = file->private_data;
1985 struct tun_struct *tun = tun_get(tfile);
1986 ssize_t result;
1987
1988 if (!tun)
1989 return -EBADFD;
1990
1991 result = tun_get_user(tun, tfile, NULL, from,
1992 file->f_flags & O_NONBLOCK, false);
1993
1994 tun_put(tun);
1995 return result;
1996 }
1997
1998 static ssize_t tun_put_user_xdp(struct tun_struct *tun,
1999 struct tun_file *tfile,
2000 struct xdp_frame *xdp_frame,
2001 struct iov_iter *iter)
2002 {
2003 int vnet_hdr_sz = 0;
2004 size_t size = xdp_frame->len;
2005 struct tun_pcpu_stats *stats;
2006 size_t ret;
2007
2008 if (tun->flags & IFF_VNET_HDR) {
2009 struct virtio_net_hdr gso = { 0 };
2010
2011 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2012 if (unlikely(iov_iter_count(iter) < vnet_hdr_sz))
2013 return -EINVAL;
2014 if (unlikely(copy_to_iter(&gso, sizeof(gso), iter) !=
2015 sizeof(gso)))
2016 return -EFAULT;
2017 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2018 }
2019
2020 ret = copy_to_iter(xdp_frame->data, size, iter) + vnet_hdr_sz;
2021
2022 stats = get_cpu_ptr(tun->pcpu_stats);
2023 u64_stats_update_begin(&stats->syncp);
2024 u64_stats_inc(&stats->tx_packets);
2025 u64_stats_add(&stats->tx_bytes, ret);
2026 u64_stats_update_end(&stats->syncp);
2027 put_cpu_ptr(tun->pcpu_stats);
2028
2029 return ret;
2030 }
2031
2032 /* Put packet to the user space buffer */
2033 static ssize_t tun_put_user(struct tun_struct *tun,
2034 struct tun_file *tfile,
2035 struct sk_buff *skb,
2036 struct iov_iter *iter)
2037 {
2038 struct tun_pi pi = { 0, skb->protocol };
2039 struct tun_pcpu_stats *stats;
2040 ssize_t total;
2041 int vlan_offset = 0;
2042 int vlan_hlen = 0;
2043 int vnet_hdr_sz = 0;
2044
2045 if (skb_vlan_tag_present(skb))
2046 vlan_hlen = VLAN_HLEN;
2047
2048 if (tun->flags & IFF_VNET_HDR)
2049 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2050
2051 total = skb->len + vlan_hlen + vnet_hdr_sz;
2052
2053 if (!(tun->flags & IFF_NO_PI)) {
2054 if (iov_iter_count(iter) < sizeof(pi))
2055 return -EINVAL;
2056
2057 total += sizeof(pi);
2058 if (iov_iter_count(iter) < total) {
2059 /* Packet will be striped */
2060 pi.flags |= TUN_PKT_STRIP;
2061 }
2062
2063 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
2064 return -EFAULT;
2065 }
2066
2067 if (vnet_hdr_sz) {
2068 struct virtio_net_hdr gso;
2069
2070 if (iov_iter_count(iter) < vnet_hdr_sz)
2071 return -EINVAL;
2072
2073 if (virtio_net_hdr_from_skb(skb, &gso,
2074 tun_is_little_endian(tun), true,
2075 vlan_hlen)) {
2076 struct skb_shared_info *sinfo = skb_shinfo(skb);
2077 pr_err("unexpected GSO type: "
2078 "0x%x, gso_size %d, hdr_len %d\n",
2079 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
2080 tun16_to_cpu(tun, gso.hdr_len));
2081 print_hex_dump(KERN_ERR, "tun: ",
2082 DUMP_PREFIX_NONE,
2083 16, 1, skb->head,
2084 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
2085 WARN_ON_ONCE(1);
2086 return -EINVAL;
2087 }
2088
2089 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
2090 return -EFAULT;
2091
2092 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2093 }
2094
2095 if (vlan_hlen) {
2096 int ret;
2097 struct veth veth;
2098
2099 veth.h_vlan_proto = skb->vlan_proto;
2100 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
2101
2102 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
2103
2104 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
2105 if (ret || !iov_iter_count(iter))
2106 goto done;
2107
2108 ret = copy_to_iter(&veth, sizeof(veth), iter);
2109 if (ret != sizeof(veth) || !iov_iter_count(iter))
2110 goto done;
2111 }
2112
2113 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
2114
2115 done:
2116 /* caller is in process context, */
2117 stats = get_cpu_ptr(tun->pcpu_stats);
2118 u64_stats_update_begin(&stats->syncp);
2119 u64_stats_inc(&stats->tx_packets);
2120 u64_stats_add(&stats->tx_bytes, skb->len + vlan_hlen);
2121 u64_stats_update_end(&stats->syncp);
2122 put_cpu_ptr(tun->pcpu_stats);
2123
2124 return total;
2125 }
2126
2127 static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err)
2128 {
2129 DECLARE_WAITQUEUE(wait, current);
2130 void *ptr = NULL;
2131 int error = 0;
2132
2133 ptr = ptr_ring_consume(&tfile->tx_ring);
2134 if (ptr)
2135 goto out;
2136 if (noblock) {
2137 error = -EAGAIN;
2138 goto out;
2139 }
2140
2141 add_wait_queue(&tfile->socket.wq.wait, &wait);
2142
2143 while (1) {
2144 set_current_state(TASK_INTERRUPTIBLE);
2145 ptr = ptr_ring_consume(&tfile->tx_ring);
2146 if (ptr)
2147 break;
2148 if (signal_pending(current)) {
2149 error = -ERESTARTSYS;
2150 break;
2151 }
2152 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
2153 error = -EFAULT;
2154 break;
2155 }
2156
2157 schedule();
2158 }
2159
2160 __set_current_state(TASK_RUNNING);
2161 remove_wait_queue(&tfile->socket.wq.wait, &wait);
2162
2163 out:
2164 *err = error;
2165 return ptr;
2166 }
2167
2168 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
2169 struct iov_iter *to,
2170 int noblock, void *ptr)
2171 {
2172 ssize_t ret;
2173 int err;
2174
2175 if (!iov_iter_count(to)) {
2176 tun_ptr_free(ptr);
2177 return 0;
2178 }
2179
2180 if (!ptr) {
2181 /* Read frames from ring */
2182 ptr = tun_ring_recv(tfile, noblock, &err);
2183 if (!ptr)
2184 return err;
2185 }
2186
2187 if (tun_is_xdp_frame(ptr)) {
2188 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2189
2190 ret = tun_put_user_xdp(tun, tfile, xdpf, to);
2191 xdp_return_frame(xdpf);
2192 } else {
2193 struct sk_buff *skb = ptr;
2194
2195 ret = tun_put_user(tun, tfile, skb, to);
2196 if (unlikely(ret < 0))
2197 kfree_skb(skb);
2198 else
2199 consume_skb(skb);
2200 }
2201
2202 return ret;
2203 }
2204
2205 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
2206 {
2207 struct file *file = iocb->ki_filp;
2208 struct tun_file *tfile = file->private_data;
2209 struct tun_struct *tun = tun_get(tfile);
2210 ssize_t len = iov_iter_count(to), ret;
2211
2212 if (!tun)
2213 return -EBADFD;
2214 ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK, NULL);
2215 ret = min_t(ssize_t, ret, len);
2216 if (ret > 0)
2217 iocb->ki_pos = ret;
2218 tun_put(tun);
2219 return ret;
2220 }
2221
2222 static void tun_prog_free(struct rcu_head *rcu)
2223 {
2224 struct tun_prog *prog = container_of(rcu, struct tun_prog, rcu);
2225
2226 bpf_prog_destroy(prog->prog);
2227 kfree(prog);
2228 }
2229
2230 static int __tun_set_ebpf(struct tun_struct *tun,
2231 struct tun_prog __rcu **prog_p,
2232 struct bpf_prog *prog)
2233 {
2234 struct tun_prog *old, *new = NULL;
2235
2236 if (prog) {
2237 new = kmalloc(sizeof(*new), GFP_KERNEL);
2238 if (!new)
2239 return -ENOMEM;
2240 new->prog = prog;
2241 }
2242
2243 spin_lock_bh(&tun->lock);
2244 old = rcu_dereference_protected(*prog_p,
2245 lockdep_is_held(&tun->lock));
2246 rcu_assign_pointer(*prog_p, new);
2247 spin_unlock_bh(&tun->lock);
2248
2249 if (old)
2250 call_rcu(&old->rcu, tun_prog_free);
2251
2252 return 0;
2253 }
2254
2255 static void tun_free_netdev(struct net_device *dev)
2256 {
2257 struct tun_struct *tun = netdev_priv(dev);
2258
2259 BUG_ON(!(list_empty(&tun->disabled)));
2260
2261 free_percpu(tun->pcpu_stats);
2262 /* We clear pcpu_stats so that tun_set_iff() can tell if
2263 * tun_free_netdev() has been called from register_netdevice().
2264 */
2265 tun->pcpu_stats = NULL;
2266
2267 tun_flow_uninit(tun);
2268 security_tun_dev_free_security(tun->security);
2269 __tun_set_ebpf(tun, &tun->steering_prog, NULL);
2270 __tun_set_ebpf(tun, &tun->filter_prog, NULL);
2271 }
2272
2273 static void tun_setup(struct net_device *dev)
2274 {
2275 struct tun_struct *tun = netdev_priv(dev);
2276
2277 tun->owner = INVALID_UID;
2278 tun->group = INVALID_GID;
2279 tun_default_link_ksettings(dev, &tun->link_ksettings);
2280
2281 dev->ethtool_ops = &tun_ethtool_ops;
2282 dev->needs_free_netdev = true;
2283 dev->priv_destructor = tun_free_netdev;
2284 /* We prefer our own queue length */
2285 dev->tx_queue_len = TUN_READQ_SIZE;
2286 }
2287
2288 /* Trivial set of netlink ops to allow deleting tun or tap
2289 * device with netlink.
2290 */
2291 static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
2292 struct netlink_ext_ack *extack)
2293 {
2294 NL_SET_ERR_MSG(extack,
2295 "tun/tap creation via rtnetlink is not supported.");
2296 return -EOPNOTSUPP;
2297 }
2298
2299 static size_t tun_get_size(const struct net_device *dev)
2300 {
2301 BUILD_BUG_ON(sizeof(u32) != sizeof(uid_t));
2302 BUILD_BUG_ON(sizeof(u32) != sizeof(gid_t));
2303
2304 return nla_total_size(sizeof(uid_t)) + /* OWNER */
2305 nla_total_size(sizeof(gid_t)) + /* GROUP */
2306 nla_total_size(sizeof(u8)) + /* TYPE */
2307 nla_total_size(sizeof(u8)) + /* PI */
2308 nla_total_size(sizeof(u8)) + /* VNET_HDR */
2309 nla_total_size(sizeof(u8)) + /* PERSIST */
2310 nla_total_size(sizeof(u8)) + /* MULTI_QUEUE */
2311 nla_total_size(sizeof(u32)) + /* NUM_QUEUES */
2312 nla_total_size(sizeof(u32)) + /* NUM_DISABLED_QUEUES */
2313 0;
2314 }
2315
2316 static int tun_fill_info(struct sk_buff *skb, const struct net_device *dev)
2317 {
2318 struct tun_struct *tun = netdev_priv(dev);
2319
2320 if (nla_put_u8(skb, IFLA_TUN_TYPE, tun->flags & TUN_TYPE_MASK))
2321 goto nla_put_failure;
2322 if (uid_valid(tun->owner) &&
2323 nla_put_u32(skb, IFLA_TUN_OWNER,
2324 from_kuid_munged(current_user_ns(), tun->owner)))
2325 goto nla_put_failure;
2326 if (gid_valid(tun->group) &&
2327 nla_put_u32(skb, IFLA_TUN_GROUP,
2328 from_kgid_munged(current_user_ns(), tun->group)))
2329 goto nla_put_failure;
2330 if (nla_put_u8(skb, IFLA_TUN_PI, !(tun->flags & IFF_NO_PI)))
2331 goto nla_put_failure;
2332 if (nla_put_u8(skb, IFLA_TUN_VNET_HDR, !!(tun->flags & IFF_VNET_HDR)))
2333 goto nla_put_failure;
2334 if (nla_put_u8(skb, IFLA_TUN_PERSIST, !!(tun->flags & IFF_PERSIST)))
2335 goto nla_put_failure;
2336 if (nla_put_u8(skb, IFLA_TUN_MULTI_QUEUE,
2337 !!(tun->flags & IFF_MULTI_QUEUE)))
2338 goto nla_put_failure;
2339 if (tun->flags & IFF_MULTI_QUEUE) {
2340 if (nla_put_u32(skb, IFLA_TUN_NUM_QUEUES, tun->numqueues))
2341 goto nla_put_failure;
2342 if (nla_put_u32(skb, IFLA_TUN_NUM_DISABLED_QUEUES,
2343 tun->numdisabled))
2344 goto nla_put_failure;
2345 }
2346
2347 return 0;
2348
2349 nla_put_failure:
2350 return -EMSGSIZE;
2351 }
2352
2353 static struct rtnl_link_ops tun_link_ops __read_mostly = {
2354 .kind = DRV_NAME,
2355 .priv_size = sizeof(struct tun_struct),
2356 .setup = tun_setup,
2357 .validate = tun_validate,
2358 .get_size = tun_get_size,
2359 .fill_info = tun_fill_info,
2360 };
2361
2362 static void tun_sock_write_space(struct sock *sk)
2363 {
2364 struct tun_file *tfile;
2365 wait_queue_head_t *wqueue;
2366
2367 if (!sock_writeable(sk))
2368 return;
2369
2370 if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
2371 return;
2372
2373 wqueue = sk_sleep(sk);
2374 if (wqueue && waitqueue_active(wqueue))
2375 wake_up_interruptible_sync_poll(wqueue, EPOLLOUT |
2376 EPOLLWRNORM | EPOLLWRBAND);
2377
2378 tfile = container_of(sk, struct tun_file, sk);
2379 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
2380 }
2381
2382 static void tun_put_page(struct tun_page *tpage)
2383 {
2384 if (tpage->page)
2385 __page_frag_cache_drain(tpage->page, tpage->count);
2386 }
2387
2388 static int tun_xdp_one(struct tun_struct *tun,
2389 struct tun_file *tfile,
2390 struct xdp_buff *xdp, int *flush,
2391 struct tun_page *tpage)
2392 {
2393 unsigned int datasize = xdp->data_end - xdp->data;
2394 struct tun_xdp_hdr *hdr = xdp->data_hard_start;
2395 struct virtio_net_hdr *gso = &hdr->gso;
2396 struct tun_pcpu_stats *stats;
2397 struct bpf_prog *xdp_prog;
2398 struct sk_buff *skb = NULL;
2399 u32 rxhash = 0, act;
2400 int buflen = hdr->buflen;
2401 int err = 0;
2402 bool skb_xdp = false;
2403 struct page *page;
2404
2405 xdp_prog = rcu_dereference(tun->xdp_prog);
2406 if (xdp_prog) {
2407 if (gso->gso_type) {
2408 skb_xdp = true;
2409 goto build;
2410 }
2411 xdp_set_data_meta_invalid(xdp);
2412 xdp->rxq = &tfile->xdp_rxq;
2413
2414 act = bpf_prog_run_xdp(xdp_prog, xdp);
2415 err = tun_xdp_act(tun, xdp_prog, xdp, act);
2416 if (err < 0) {
2417 put_page(virt_to_head_page(xdp->data));
2418 return err;
2419 }
2420
2421 switch (err) {
2422 case XDP_REDIRECT:
2423 *flush = true;
2424 /* fall through */
2425 case XDP_TX:
2426 return 0;
2427 case XDP_PASS:
2428 break;
2429 default:
2430 page = virt_to_head_page(xdp->data);
2431 if (tpage->page == page) {
2432 ++tpage->count;
2433 } else {
2434 tun_put_page(tpage);
2435 tpage->page = page;
2436 tpage->count = 1;
2437 }
2438 return 0;
2439 }
2440 }
2441
2442 build:
2443 skb = build_skb(xdp->data_hard_start, buflen);
2444 if (!skb) {
2445 err = -ENOMEM;
2446 goto out;
2447 }
2448
2449 skb_reserve(skb, xdp->data - xdp->data_hard_start);
2450 skb_put(skb, xdp->data_end - xdp->data);
2451
2452 if (virtio_net_hdr_to_skb(skb, gso, tun_is_little_endian(tun))) {
2453 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
2454 kfree_skb(skb);
2455 err = -EINVAL;
2456 goto out;
2457 }
2458
2459 skb->protocol = eth_type_trans(skb, tun->dev);
2460 skb_reset_network_header(skb);
2461 skb_probe_transport_header(skb);
2462
2463 if (skb_xdp) {
2464 err = do_xdp_generic(xdp_prog, skb);
2465 if (err != XDP_PASS)
2466 goto out;
2467 }
2468
2469 if (!rcu_dereference(tun->steering_prog) && tun->numqueues > 1 &&
2470 !tfile->detached)
2471 rxhash = __skb_get_hash_symmetric(skb);
2472
2473 skb_record_rx_queue(skb, tfile->queue_index);
2474 netif_receive_skb(skb);
2475
2476 /* No need for get_cpu_ptr() here since this function is
2477 * always called with bh disabled
2478 */
2479 stats = this_cpu_ptr(tun->pcpu_stats);
2480 u64_stats_update_begin(&stats->syncp);
2481 u64_stats_inc(&stats->rx_packets);
2482 u64_stats_add(&stats->rx_bytes, datasize);
2483 u64_stats_update_end(&stats->syncp);
2484
2485 if (rxhash)
2486 tun_flow_update(tun, rxhash, tfile);
2487
2488 out:
2489 return err;
2490 }
2491
2492 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
2493 {
2494 int ret, i;
2495 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2496 struct tun_struct *tun = tun_get(tfile);
2497 struct tun_msg_ctl *ctl = m->msg_control;
2498 struct xdp_buff *xdp;
2499
2500 if (!tun)
2501 return -EBADFD;
2502
2503 if (ctl && (ctl->type == TUN_MSG_PTR)) {
2504 struct tun_page tpage;
2505 int n = ctl->num;
2506 int flush = 0;
2507
2508 memset(&tpage, 0, sizeof(tpage));
2509
2510 local_bh_disable();
2511 rcu_read_lock();
2512
2513 for (i = 0; i < n; i++) {
2514 xdp = &((struct xdp_buff *)ctl->ptr)[i];
2515 tun_xdp_one(tun, tfile, xdp, &flush, &tpage);
2516 }
2517
2518 if (flush)
2519 xdp_do_flush();
2520
2521 rcu_read_unlock();
2522 local_bh_enable();
2523
2524 tun_put_page(&tpage);
2525
2526 ret = total_len;
2527 goto out;
2528 }
2529
2530 ret = tun_get_user(tun, tfile, ctl ? ctl->ptr : NULL, &m->msg_iter,
2531 m->msg_flags & MSG_DONTWAIT,
2532 m->msg_flags & MSG_MORE);
2533 out:
2534 tun_put(tun);
2535 return ret;
2536 }
2537
2538 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
2539 int flags)
2540 {
2541 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2542 struct tun_struct *tun = tun_get(tfile);
2543 void *ptr = m->msg_control;
2544 int ret;
2545
2546 if (!tun) {
2547 ret = -EBADFD;
2548 goto out_free;
2549 }
2550
2551 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
2552 ret = -EINVAL;
2553 goto out_put_tun;
2554 }
2555 if (flags & MSG_ERRQUEUE) {
2556 ret = sock_recv_errqueue(sock->sk, m, total_len,
2557 SOL_PACKET, TUN_TX_TIMESTAMP);
2558 goto out;
2559 }
2560 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT, ptr);
2561 if (ret > (ssize_t)total_len) {
2562 m->msg_flags |= MSG_TRUNC;
2563 ret = flags & MSG_TRUNC ? ret : total_len;
2564 }
2565 out:
2566 tun_put(tun);
2567 return ret;
2568
2569 out_put_tun:
2570 tun_put(tun);
2571 out_free:
2572 tun_ptr_free(ptr);
2573 return ret;
2574 }
2575
2576 static int tun_ptr_peek_len(void *ptr)
2577 {
2578 if (likely(ptr)) {
2579 if (tun_is_xdp_frame(ptr)) {
2580 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2581
2582 return xdpf->len;
2583 }
2584 return __skb_array_len_with_tag(ptr);
2585 } else {
2586 return 0;
2587 }
2588 }
2589
2590 static int tun_peek_len(struct socket *sock)
2591 {
2592 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2593 struct tun_struct *tun;
2594 int ret = 0;
2595
2596 tun = tun_get(tfile);
2597 if (!tun)
2598 return 0;
2599
2600 ret = PTR_RING_PEEK_CALL(&tfile->tx_ring, tun_ptr_peek_len);
2601 tun_put(tun);
2602
2603 return ret;
2604 }
2605
2606 /* Ops structure to mimic raw sockets with tun */
2607 static const struct proto_ops tun_socket_ops = {
2608 .peek_len = tun_peek_len,
2609 .sendmsg = tun_sendmsg,
2610 .recvmsg = tun_recvmsg,
2611 };
2612
2613 static struct proto tun_proto = {
2614 .name = "tun",
2615 .owner = THIS_MODULE,
2616 .obj_size = sizeof(struct tun_file),
2617 };
2618
2619 static int tun_flags(struct tun_struct *tun)
2620 {
2621 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
2622 }
2623
2624 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
2625 char *buf)
2626 {
2627 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2628 return sprintf(buf, "0x%x\n", tun_flags(tun));
2629 }
2630
2631 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
2632 char *buf)
2633 {
2634 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2635 return uid_valid(tun->owner)?
2636 sprintf(buf, "%u\n",
2637 from_kuid_munged(current_user_ns(), tun->owner)):
2638 sprintf(buf, "-1\n");
2639 }
2640
2641 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
2642 char *buf)
2643 {
2644 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2645 return gid_valid(tun->group) ?
2646 sprintf(buf, "%u\n",
2647 from_kgid_munged(current_user_ns(), tun->group)):
2648 sprintf(buf, "-1\n");
2649 }
2650
2651 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
2652 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
2653 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
2654
2655 static struct attribute *tun_dev_attrs[] = {
2656 &dev_attr_tun_flags.attr,
2657 &dev_attr_owner.attr,
2658 &dev_attr_group.attr,
2659 NULL
2660 };
2661
2662 static const struct attribute_group tun_attr_group = {
2663 .attrs = tun_dev_attrs
2664 };
2665
2666 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
2667 {
2668 struct tun_struct *tun;
2669 struct tun_file *tfile = file->private_data;
2670 struct net_device *dev;
2671 int err;
2672
2673 if (tfile->detached)
2674 return -EINVAL;
2675
2676 if ((ifr->ifr_flags & IFF_NAPI_FRAGS)) {
2677 if (!capable(CAP_NET_ADMIN))
2678 return -EPERM;
2679
2680 if (!(ifr->ifr_flags & IFF_NAPI) ||
2681 (ifr->ifr_flags & TUN_TYPE_MASK) != IFF_TAP)
2682 return -EINVAL;
2683 }
2684
2685 dev = __dev_get_by_name(net, ifr->ifr_name);
2686 if (dev) {
2687 if (ifr->ifr_flags & IFF_TUN_EXCL)
2688 return -EBUSY;
2689 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
2690 tun = netdev_priv(dev);
2691 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
2692 tun = netdev_priv(dev);
2693 else
2694 return -EINVAL;
2695
2696 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
2697 !!(tun->flags & IFF_MULTI_QUEUE))
2698 return -EINVAL;
2699
2700 if (tun_not_capable(tun))
2701 return -EPERM;
2702 err = security_tun_dev_open(tun->security);
2703 if (err < 0)
2704 return err;
2705
2706 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER,
2707 ifr->ifr_flags & IFF_NAPI,
2708 ifr->ifr_flags & IFF_NAPI_FRAGS, true);
2709 if (err < 0)
2710 return err;
2711
2712 if (tun->flags & IFF_MULTI_QUEUE &&
2713 (tun->numqueues + tun->numdisabled > 1)) {
2714 /* One or more queue has already been attached, no need
2715 * to initialize the device again.
2716 */
2717 netdev_state_change(dev);
2718 return 0;
2719 }
2720
2721 tun->flags = (tun->flags & ~TUN_FEATURES) |
2722 (ifr->ifr_flags & TUN_FEATURES);
2723
2724 netdev_state_change(dev);
2725 } else {
2726 char *name;
2727 unsigned long flags = 0;
2728 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
2729 MAX_TAP_QUEUES : 1;
2730
2731 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2732 return -EPERM;
2733 err = security_tun_dev_create();
2734 if (err < 0)
2735 return err;
2736
2737 /* Set dev type */
2738 if (ifr->ifr_flags & IFF_TUN) {
2739 /* TUN device */
2740 flags |= IFF_TUN;
2741 name = "tun%d";
2742 } else if (ifr->ifr_flags & IFF_TAP) {
2743 /* TAP device */
2744 flags |= IFF_TAP;
2745 name = "tap%d";
2746 } else
2747 return -EINVAL;
2748
2749 if (*ifr->ifr_name)
2750 name = ifr->ifr_name;
2751
2752 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
2753 NET_NAME_UNKNOWN, tun_setup, queues,
2754 queues);
2755
2756 if (!dev)
2757 return -ENOMEM;
2758
2759 dev_net_set(dev, net);
2760 dev->rtnl_link_ops = &tun_link_ops;
2761 dev->ifindex = tfile->ifindex;
2762 dev->sysfs_groups[0] = &tun_attr_group;
2763
2764 tun = netdev_priv(dev);
2765 tun->dev = dev;
2766 tun->flags = flags;
2767 tun->txflt.count = 0;
2768 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
2769
2770 tun->align = NET_SKB_PAD;
2771 tun->filter_attached = false;
2772 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
2773 tun->rx_batched = 0;
2774 RCU_INIT_POINTER(tun->steering_prog, NULL);
2775
2776 tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats);
2777 if (!tun->pcpu_stats) {
2778 err = -ENOMEM;
2779 goto err_free_dev;
2780 }
2781
2782 spin_lock_init(&tun->lock);
2783
2784 err = security_tun_dev_alloc_security(&tun->security);
2785 if (err < 0)
2786 goto err_free_stat;
2787
2788 tun_net_init(dev);
2789 tun_flow_init(tun);
2790
2791 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
2792 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
2793 NETIF_F_HW_VLAN_STAG_TX;
2794 dev->features = dev->hw_features | NETIF_F_LLTX;
2795 dev->vlan_features = dev->features &
2796 ~(NETIF_F_HW_VLAN_CTAG_TX |
2797 NETIF_F_HW_VLAN_STAG_TX);
2798
2799 tun->flags = (tun->flags & ~TUN_FEATURES) |
2800 (ifr->ifr_flags & TUN_FEATURES);
2801
2802 INIT_LIST_HEAD(&tun->disabled);
2803 err = tun_attach(tun, file, false, ifr->ifr_flags & IFF_NAPI,
2804 ifr->ifr_flags & IFF_NAPI_FRAGS, false);
2805 if (err < 0)
2806 goto err_free_flow;
2807
2808 err = register_netdevice(tun->dev);
2809 if (err < 0)
2810 goto err_detach;
2811 /* free_netdev() won't check refcnt, to aovid race
2812 * with dev_put() we need publish tun after registration.
2813 */
2814 rcu_assign_pointer(tfile->tun, tun);
2815 }
2816
2817 netif_carrier_on(tun->dev);
2818
2819 /* Make sure persistent devices do not get stuck in
2820 * xoff state.
2821 */
2822 if (netif_running(tun->dev))
2823 netif_tx_wake_all_queues(tun->dev);
2824
2825 strcpy(ifr->ifr_name, tun->dev->name);
2826 return 0;
2827
2828 err_detach:
2829 tun_detach_all(dev);
2830 /* We are here because register_netdevice() has failed.
2831 * If register_netdevice() already called tun_free_netdev()
2832 * while dealing with the error, tun->pcpu_stats has been cleared.
2833 */
2834 if (!tun->pcpu_stats)
2835 goto err_free_dev;
2836
2837 err_free_flow:
2838 tun_flow_uninit(tun);
2839 security_tun_dev_free_security(tun->security);
2840 err_free_stat:
2841 free_percpu(tun->pcpu_stats);
2842 err_free_dev:
2843 free_netdev(dev);
2844 return err;
2845 }
2846
2847 static void tun_get_iff(struct tun_struct *tun, struct ifreq *ifr)
2848 {
2849 strcpy(ifr->ifr_name, tun->dev->name);
2850
2851 ifr->ifr_flags = tun_flags(tun);
2852
2853 }
2854
2855 /* This is like a cut-down ethtool ops, except done via tun fd so no
2856 * privs required. */
2857 static int set_offload(struct tun_struct *tun, unsigned long arg)
2858 {
2859 netdev_features_t features = 0;
2860
2861 if (arg & TUN_F_CSUM) {
2862 features |= NETIF_F_HW_CSUM;
2863 arg &= ~TUN_F_CSUM;
2864
2865 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
2866 if (arg & TUN_F_TSO_ECN) {
2867 features |= NETIF_F_TSO_ECN;
2868 arg &= ~TUN_F_TSO_ECN;
2869 }
2870 if (arg & TUN_F_TSO4)
2871 features |= NETIF_F_TSO;
2872 if (arg & TUN_F_TSO6)
2873 features |= NETIF_F_TSO6;
2874 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
2875 }
2876
2877 arg &= ~TUN_F_UFO;
2878 }
2879
2880 /* This gives the user a way to test for new features in future by
2881 * trying to set them. */
2882 if (arg)
2883 return -EINVAL;
2884
2885 tun->set_features = features;
2886 tun->dev->wanted_features &= ~TUN_USER_FEATURES;
2887 tun->dev->wanted_features |= features;
2888 netdev_update_features(tun->dev);
2889
2890 return 0;
2891 }
2892
2893 static void tun_detach_filter(struct tun_struct *tun, int n)
2894 {
2895 int i;
2896 struct tun_file *tfile;
2897
2898 for (i = 0; i < n; i++) {
2899 tfile = rtnl_dereference(tun->tfiles[i]);
2900 lock_sock(tfile->socket.sk);
2901 sk_detach_filter(tfile->socket.sk);
2902 release_sock(tfile->socket.sk);
2903 }
2904
2905 tun->filter_attached = false;
2906 }
2907
2908 static int tun_attach_filter(struct tun_struct *tun)
2909 {
2910 int i, ret = 0;
2911 struct tun_file *tfile;
2912
2913 for (i = 0; i < tun->numqueues; i++) {
2914 tfile = rtnl_dereference(tun->tfiles[i]);
2915 lock_sock(tfile->socket.sk);
2916 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
2917 release_sock(tfile->socket.sk);
2918 if (ret) {
2919 tun_detach_filter(tun, i);
2920 return ret;
2921 }
2922 }
2923
2924 tun->filter_attached = true;
2925 return ret;
2926 }
2927
2928 static void tun_set_sndbuf(struct tun_struct *tun)
2929 {
2930 struct tun_file *tfile;
2931 int i;
2932
2933 for (i = 0; i < tun->numqueues; i++) {
2934 tfile = rtnl_dereference(tun->tfiles[i]);
2935 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
2936 }
2937 }
2938
2939 static int tun_set_queue(struct file *file, struct ifreq *ifr)
2940 {
2941 struct tun_file *tfile = file->private_data;
2942 struct tun_struct *tun;
2943 int ret = 0;
2944
2945 rtnl_lock();
2946
2947 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
2948 tun = tfile->detached;
2949 if (!tun) {
2950 ret = -EINVAL;
2951 goto unlock;
2952 }
2953 ret = security_tun_dev_attach_queue(tun->security);
2954 if (ret < 0)
2955 goto unlock;
2956 ret = tun_attach(tun, file, false, tun->flags & IFF_NAPI,
2957 tun->flags & IFF_NAPI_FRAGS, true);
2958 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
2959 tun = rtnl_dereference(tfile->tun);
2960 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
2961 ret = -EINVAL;
2962 else
2963 __tun_detach(tfile, false);
2964 } else
2965 ret = -EINVAL;
2966
2967 if (ret >= 0)
2968 netdev_state_change(tun->dev);
2969
2970 unlock:
2971 rtnl_unlock();
2972 return ret;
2973 }
2974
2975 static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog **prog_p,
2976 void __user *data)
2977 {
2978 struct bpf_prog *prog;
2979 int fd;
2980
2981 if (copy_from_user(&fd, data, sizeof(fd)))
2982 return -EFAULT;
2983
2984 if (fd == -1) {
2985 prog = NULL;
2986 } else {
2987 prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
2988 if (IS_ERR(prog))
2989 return PTR_ERR(prog);
2990 }
2991
2992 return __tun_set_ebpf(tun, prog_p, prog);
2993 }
2994
2995 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
2996 unsigned long arg, int ifreq_len)
2997 {
2998 struct tun_file *tfile = file->private_data;
2999 struct net *net = sock_net(&tfile->sk);
3000 struct tun_struct *tun;
3001 void __user* argp = (void __user*)arg;
3002 unsigned int ifindex, carrier;
3003 struct ifreq ifr;
3004 kuid_t owner;
3005 kgid_t group;
3006 int sndbuf;
3007 int vnet_hdr_sz;
3008 int le;
3009 int ret;
3010 bool do_notify = false;
3011
3012 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE ||
3013 (_IOC_TYPE(cmd) == SOCK_IOC_TYPE && cmd != SIOCGSKNS)) {
3014 if (copy_from_user(&ifr, argp, ifreq_len))
3015 return -EFAULT;
3016 } else {
3017 memset(&ifr, 0, sizeof(ifr));
3018 }
3019 if (cmd == TUNGETFEATURES) {
3020 /* Currently this just means: "what IFF flags are valid?".
3021 * This is needed because we never checked for invalid flags on
3022 * TUNSETIFF.
3023 */
3024 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
3025 (unsigned int __user*)argp);
3026 } else if (cmd == TUNSETQUEUE) {
3027 return tun_set_queue(file, &ifr);
3028 } else if (cmd == SIOCGSKNS) {
3029 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3030 return -EPERM;
3031 return open_related_ns(&net->ns, get_net_ns);
3032 }
3033
3034 ret = 0;
3035 rtnl_lock();
3036
3037 tun = tun_get(tfile);
3038 if (cmd == TUNSETIFF) {
3039 ret = -EEXIST;
3040 if (tun)
3041 goto unlock;
3042
3043 ifr.ifr_name[IFNAMSIZ-1] = '\0';
3044
3045 ret = tun_set_iff(net, file, &ifr);
3046
3047 if (ret)
3048 goto unlock;
3049
3050 if (copy_to_user(argp, &ifr, ifreq_len))
3051 ret = -EFAULT;
3052 goto unlock;
3053 }
3054 if (cmd == TUNSETIFINDEX) {
3055 ret = -EPERM;
3056 if (tun)
3057 goto unlock;
3058
3059 ret = -EFAULT;
3060 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
3061 goto unlock;
3062
3063 ret = 0;
3064 tfile->ifindex = ifindex;
3065 goto unlock;
3066 }
3067
3068 ret = -EBADFD;
3069 if (!tun)
3070 goto unlock;
3071
3072 netif_info(tun, drv, tun->dev, "tun_chr_ioctl cmd %u\n", cmd);
3073
3074 net = dev_net(tun->dev);
3075 ret = 0;
3076 switch (cmd) {
3077 case TUNGETIFF:
3078 tun_get_iff(tun, &ifr);
3079
3080 if (tfile->detached)
3081 ifr.ifr_flags |= IFF_DETACH_QUEUE;
3082 if (!tfile->socket.sk->sk_filter)
3083 ifr.ifr_flags |= IFF_NOFILTER;
3084
3085 if (copy_to_user(argp, &ifr, ifreq_len))
3086 ret = -EFAULT;
3087 break;
3088
3089 case TUNSETNOCSUM:
3090 /* Disable/Enable checksum */
3091
3092 /* [unimplemented] */
3093 netif_info(tun, drv, tun->dev, "ignored: set checksum %s\n",
3094 arg ? "disabled" : "enabled");
3095 break;
3096
3097 case TUNSETPERSIST:
3098 /* Disable/Enable persist mode. Keep an extra reference to the
3099 * module to prevent the module being unprobed.
3100 */
3101 if (arg && !(tun->flags & IFF_PERSIST)) {
3102 tun->flags |= IFF_PERSIST;
3103 __module_get(THIS_MODULE);
3104 do_notify = true;
3105 }
3106 if (!arg && (tun->flags & IFF_PERSIST)) {
3107 tun->flags &= ~IFF_PERSIST;
3108 module_put(THIS_MODULE);
3109 do_notify = true;
3110 }
3111
3112 netif_info(tun, drv, tun->dev, "persist %s\n",
3113 arg ? "enabled" : "disabled");
3114 break;
3115
3116 case TUNSETOWNER:
3117 /* Set owner of the device */
3118 owner = make_kuid(current_user_ns(), arg);
3119 if (!uid_valid(owner)) {
3120 ret = -EINVAL;
3121 break;
3122 }
3123 tun->owner = owner;
3124 do_notify = true;
3125 netif_info(tun, drv, tun->dev, "owner set to %u\n",
3126 from_kuid(&init_user_ns, tun->owner));
3127 break;
3128
3129 case TUNSETGROUP:
3130 /* Set group of the device */
3131 group = make_kgid(current_user_ns(), arg);
3132 if (!gid_valid(group)) {
3133 ret = -EINVAL;
3134 break;
3135 }
3136 tun->group = group;
3137 do_notify = true;
3138 netif_info(tun, drv, tun->dev, "group set to %u\n",
3139 from_kgid(&init_user_ns, tun->group));
3140 break;
3141
3142 case TUNSETLINK:
3143 /* Only allow setting the type when the interface is down */
3144 if (tun->dev->flags & IFF_UP) {
3145 netif_info(tun, drv, tun->dev,
3146 "Linktype set failed because interface is up\n");
3147 ret = -EBUSY;
3148 } else {
3149 tun->dev->type = (int) arg;
3150 netif_info(tun, drv, tun->dev, "linktype set to %d\n",
3151 tun->dev->type);
3152 ret = 0;
3153 }
3154 break;
3155
3156 case TUNSETDEBUG:
3157 tun->msg_enable = (u32)arg;
3158 break;
3159
3160 case TUNSETOFFLOAD:
3161 ret = set_offload(tun, arg);
3162 break;
3163
3164 case TUNSETTXFILTER:
3165 /* Can be set only for TAPs */
3166 ret = -EINVAL;
3167 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3168 break;
3169 ret = update_filter(&tun->txflt, (void __user *)arg);
3170 break;
3171
3172 case SIOCGIFHWADDR:
3173 /* Get hw address */
3174 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
3175 ifr.ifr_hwaddr.sa_family = tun->dev->type;
3176 if (copy_to_user(argp, &ifr, ifreq_len))
3177 ret = -EFAULT;
3178 break;
3179
3180 case SIOCSIFHWADDR:
3181 /* Set hw address */
3182 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr, NULL);
3183 break;
3184
3185 case TUNGETSNDBUF:
3186 sndbuf = tfile->socket.sk->sk_sndbuf;
3187 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
3188 ret = -EFAULT;
3189 break;
3190
3191 case TUNSETSNDBUF:
3192 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
3193 ret = -EFAULT;
3194 break;
3195 }
3196 if (sndbuf <= 0) {
3197 ret = -EINVAL;
3198 break;
3199 }
3200
3201 tun->sndbuf = sndbuf;
3202 tun_set_sndbuf(tun);
3203 break;
3204
3205 case TUNGETVNETHDRSZ:
3206 vnet_hdr_sz = tun->vnet_hdr_sz;
3207 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
3208 ret = -EFAULT;
3209 break;
3210
3211 case TUNSETVNETHDRSZ:
3212 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
3213 ret = -EFAULT;
3214 break;
3215 }
3216 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
3217 ret = -EINVAL;
3218 break;
3219 }
3220
3221 tun->vnet_hdr_sz = vnet_hdr_sz;
3222 break;
3223
3224 case TUNGETVNETLE:
3225 le = !!(tun->flags & TUN_VNET_LE);
3226 if (put_user(le, (int __user *)argp))
3227 ret = -EFAULT;
3228 break;
3229
3230 case TUNSETVNETLE:
3231 if (get_user(le, (int __user *)argp)) {
3232 ret = -EFAULT;
3233 break;
3234 }
3235 if (le)
3236 tun->flags |= TUN_VNET_LE;
3237 else
3238 tun->flags &= ~TUN_VNET_LE;
3239 break;
3240
3241 case TUNGETVNETBE:
3242 ret = tun_get_vnet_be(tun, argp);
3243 break;
3244
3245 case TUNSETVNETBE:
3246 ret = tun_set_vnet_be(tun, argp);
3247 break;
3248
3249 case TUNATTACHFILTER:
3250 /* Can be set only for TAPs */
3251 ret = -EINVAL;
3252 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3253 break;
3254 ret = -EFAULT;
3255 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
3256 break;
3257
3258 ret = tun_attach_filter(tun);
3259 break;
3260
3261 case TUNDETACHFILTER:
3262 /* Can be set only for TAPs */
3263 ret = -EINVAL;
3264 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3265 break;
3266 ret = 0;
3267 tun_detach_filter(tun, tun->numqueues);
3268 break;
3269
3270 case TUNGETFILTER:
3271 ret = -EINVAL;
3272 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3273 break;
3274 ret = -EFAULT;
3275 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
3276 break;
3277 ret = 0;
3278 break;
3279
3280 case TUNSETSTEERINGEBPF:
3281 ret = tun_set_ebpf(tun, &tun->steering_prog, argp);
3282 break;
3283
3284 case TUNSETFILTEREBPF:
3285 ret = tun_set_ebpf(tun, &tun->filter_prog, argp);
3286 break;
3287
3288 case TUNSETCARRIER:
3289 ret = -EFAULT;
3290 if (copy_from_user(&carrier, argp, sizeof(carrier)))
3291 goto unlock;
3292
3293 ret = tun_net_change_carrier(tun->dev, (bool)carrier);
3294 break;
3295
3296 case TUNGETDEVNETNS:
3297 ret = -EPERM;
3298 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3299 goto unlock;
3300 ret = open_related_ns(&net->ns, get_net_ns);
3301 break;
3302
3303 default:
3304 ret = -EINVAL;
3305 break;
3306 }
3307
3308 if (do_notify)
3309 netdev_state_change(tun->dev);
3310
3311 unlock:
3312 rtnl_unlock();
3313 if (tun)
3314 tun_put(tun);
3315 return ret;
3316 }
3317
3318 static long tun_chr_ioctl(struct file *file,
3319 unsigned int cmd, unsigned long arg)
3320 {
3321 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
3322 }
3323
3324 #ifdef CONFIG_COMPAT
3325 static long tun_chr_compat_ioctl(struct file *file,
3326 unsigned int cmd, unsigned long arg)
3327 {
3328 switch (cmd) {
3329 case TUNSETIFF:
3330 case TUNGETIFF:
3331 case TUNSETTXFILTER:
3332 case TUNGETSNDBUF:
3333 case TUNSETSNDBUF:
3334 case SIOCGIFHWADDR:
3335 case SIOCSIFHWADDR:
3336 arg = (unsigned long)compat_ptr(arg);
3337 break;
3338 default:
3339 arg = (compat_ulong_t)arg;
3340 break;
3341 }
3342
3343 /*
3344 * compat_ifreq is shorter than ifreq, so we must not access beyond
3345 * the end of that structure. All fields that are used in this
3346 * driver are compatible though, we don't need to convert the
3347 * contents.
3348 */
3349 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
3350 }
3351 #endif /* CONFIG_COMPAT */
3352
3353 static int tun_chr_fasync(int fd, struct file *file, int on)
3354 {
3355 struct tun_file *tfile = file->private_data;
3356 int ret;
3357
3358 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
3359 goto out;
3360
3361 if (on) {
3362 __f_setown(file, task_pid(current), PIDTYPE_TGID, 0);
3363 tfile->flags |= TUN_FASYNC;
3364 } else
3365 tfile->flags &= ~TUN_FASYNC;
3366 ret = 0;
3367 out:
3368 return ret;
3369 }
3370
3371 static int tun_chr_open(struct inode *inode, struct file * file)
3372 {
3373 struct net *net = current->nsproxy->net_ns;
3374 struct tun_file *tfile;
3375
3376 tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
3377 &tun_proto, 0);
3378 if (!tfile)
3379 return -ENOMEM;
3380 if (ptr_ring_init(&tfile->tx_ring, 0, GFP_KERNEL)) {
3381 sk_free(&tfile->sk);
3382 return -ENOMEM;
3383 }
3384
3385 mutex_init(&tfile->napi_mutex);
3386 RCU_INIT_POINTER(tfile->tun, NULL);
3387 tfile->flags = 0;
3388 tfile->ifindex = 0;
3389
3390 init_waitqueue_head(&tfile->socket.wq.wait);
3391
3392 tfile->socket.file = file;
3393 tfile->socket.ops = &tun_socket_ops;
3394
3395 sock_init_data(&tfile->socket, &tfile->sk);
3396
3397 tfile->sk.sk_write_space = tun_sock_write_space;
3398 tfile->sk.sk_sndbuf = INT_MAX;
3399
3400 file->private_data = tfile;
3401 INIT_LIST_HEAD(&tfile->next);
3402
3403 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
3404
3405 return 0;
3406 }
3407
3408 static int tun_chr_close(struct inode *inode, struct file *file)
3409 {
3410 struct tun_file *tfile = file->private_data;
3411
3412 tun_detach(tfile, true);
3413
3414 return 0;
3415 }
3416
3417 #ifdef CONFIG_PROC_FS
3418 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *file)
3419 {
3420 struct tun_file *tfile = file->private_data;
3421 struct tun_struct *tun;
3422 struct ifreq ifr;
3423
3424 memset(&ifr, 0, sizeof(ifr));
3425
3426 rtnl_lock();
3427 tun = tun_get(tfile);
3428 if (tun)
3429 tun_get_iff(tun, &ifr);
3430 rtnl_unlock();
3431
3432 if (tun)
3433 tun_put(tun);
3434
3435 seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
3436 }
3437 #endif
3438
3439 static const struct file_operations tun_fops = {
3440 .owner = THIS_MODULE,
3441 .llseek = no_llseek,
3442 .read_iter = tun_chr_read_iter,
3443 .write_iter = tun_chr_write_iter,
3444 .poll = tun_chr_poll,
3445 .unlocked_ioctl = tun_chr_ioctl,
3446 #ifdef CONFIG_COMPAT
3447 .compat_ioctl = tun_chr_compat_ioctl,
3448 #endif
3449 .open = tun_chr_open,
3450 .release = tun_chr_close,
3451 .fasync = tun_chr_fasync,
3452 #ifdef CONFIG_PROC_FS
3453 .show_fdinfo = tun_chr_show_fdinfo,
3454 #endif
3455 };
3456
3457 static struct miscdevice tun_miscdev = {
3458 .minor = TUN_MINOR,
3459 .name = "tun",
3460 .nodename = "net/tun",
3461 .fops = &tun_fops,
3462 };
3463
3464 /* ethtool interface */
3465
3466 static void tun_default_link_ksettings(struct net_device *dev,
3467 struct ethtool_link_ksettings *cmd)
3468 {
3469 ethtool_link_ksettings_zero_link_mode(cmd, supported);
3470 ethtool_link_ksettings_zero_link_mode(cmd, advertising);
3471 cmd->base.speed = SPEED_10;
3472 cmd->base.duplex = DUPLEX_FULL;
3473 cmd->base.port = PORT_TP;
3474 cmd->base.phy_address = 0;
3475 cmd->base.autoneg = AUTONEG_DISABLE;
3476 }
3477
3478 static int tun_get_link_ksettings(struct net_device *dev,
3479 struct ethtool_link_ksettings *cmd)
3480 {
3481 struct tun_struct *tun = netdev_priv(dev);
3482
3483 memcpy(cmd, &tun->link_ksettings, sizeof(*cmd));
3484 return 0;
3485 }
3486
3487 static int tun_set_link_ksettings(struct net_device *dev,
3488 const struct ethtool_link_ksettings *cmd)
3489 {
3490 struct tun_struct *tun = netdev_priv(dev);
3491
3492 memcpy(&tun->link_ksettings, cmd, sizeof(*cmd));
3493 return 0;
3494 }
3495
3496 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
3497 {
3498 struct tun_struct *tun = netdev_priv(dev);
3499
3500 strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
3501 strlcpy(info->version, DRV_VERSION, sizeof(info->version));
3502
3503 switch (tun->flags & TUN_TYPE_MASK) {
3504 case IFF_TUN:
3505 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
3506 break;
3507 case IFF_TAP:
3508 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
3509 break;
3510 }
3511 }
3512
3513 static u32 tun_get_msglevel(struct net_device *dev)
3514 {
3515 struct tun_struct *tun = netdev_priv(dev);
3516
3517 return tun->msg_enable;
3518 }
3519
3520 static void tun_set_msglevel(struct net_device *dev, u32 value)
3521 {
3522 struct tun_struct *tun = netdev_priv(dev);
3523
3524 tun->msg_enable = value;
3525 }
3526
3527 static int tun_get_coalesce(struct net_device *dev,
3528 struct ethtool_coalesce *ec)
3529 {
3530 struct tun_struct *tun = netdev_priv(dev);
3531
3532 ec->rx_max_coalesced_frames = tun->rx_batched;
3533
3534 return 0;
3535 }
3536
3537 static int tun_set_coalesce(struct net_device *dev,
3538 struct ethtool_coalesce *ec)
3539 {
3540 struct tun_struct *tun = netdev_priv(dev);
3541
3542 if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT)
3543 tun->rx_batched = NAPI_POLL_WEIGHT;
3544 else
3545 tun->rx_batched = ec->rx_max_coalesced_frames;
3546
3547 return 0;
3548 }
3549
3550 static const struct ethtool_ops tun_ethtool_ops = {
3551 .supported_coalesce_params = ETHTOOL_COALESCE_RX_MAX_FRAMES,
3552 .get_drvinfo = tun_get_drvinfo,
3553 .get_msglevel = tun_get_msglevel,
3554 .set_msglevel = tun_set_msglevel,
3555 .get_link = ethtool_op_get_link,
3556 .get_ts_info = ethtool_op_get_ts_info,
3557 .get_coalesce = tun_get_coalesce,
3558 .set_coalesce = tun_set_coalesce,
3559 .get_link_ksettings = tun_get_link_ksettings,
3560 .set_link_ksettings = tun_set_link_ksettings,
3561 };
3562
3563 static int tun_queue_resize(struct tun_struct *tun)
3564 {
3565 struct net_device *dev = tun->dev;
3566 struct tun_file *tfile;
3567 struct ptr_ring **rings;
3568 int n = tun->numqueues + tun->numdisabled;
3569 int ret, i;
3570
3571 rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL);
3572 if (!rings)
3573 return -ENOMEM;
3574
3575 for (i = 0; i < tun->numqueues; i++) {
3576 tfile = rtnl_dereference(tun->tfiles[i]);
3577 rings[i] = &tfile->tx_ring;
3578 }
3579 list_for_each_entry(tfile, &tun->disabled, next)
3580 rings[i++] = &tfile->tx_ring;
3581
3582 ret = ptr_ring_resize_multiple(rings, n,
3583 dev->tx_queue_len, GFP_KERNEL,
3584 tun_ptr_free);
3585
3586 kfree(rings);
3587 return ret;
3588 }
3589
3590 static int tun_device_event(struct notifier_block *unused,
3591 unsigned long event, void *ptr)
3592 {
3593 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3594 struct tun_struct *tun = netdev_priv(dev);
3595 int i;
3596
3597 if (dev->rtnl_link_ops != &tun_link_ops)
3598 return NOTIFY_DONE;
3599
3600 switch (event) {
3601 case NETDEV_CHANGE_TX_QUEUE_LEN:
3602 if (tun_queue_resize(tun))
3603 return NOTIFY_BAD;
3604 break;
3605 case NETDEV_UP:
3606 for (i = 0; i < tun->numqueues; i++) {
3607 struct tun_file *tfile;
3608
3609 tfile = rtnl_dereference(tun->tfiles[i]);
3610 tfile->socket.sk->sk_write_space(tfile->socket.sk);
3611 }
3612 break;
3613 default:
3614 break;
3615 }
3616
3617 return NOTIFY_DONE;
3618 }
3619
3620 static struct notifier_block tun_notifier_block __read_mostly = {
3621 .notifier_call = tun_device_event,
3622 };
3623
3624 static int __init tun_init(void)
3625 {
3626 int ret = 0;
3627
3628 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
3629
3630 ret = rtnl_link_register(&tun_link_ops);
3631 if (ret) {
3632 pr_err("Can't register link_ops\n");
3633 goto err_linkops;
3634 }
3635
3636 ret = misc_register(&tun_miscdev);
3637 if (ret) {
3638 pr_err("Can't register misc device %d\n", TUN_MINOR);
3639 goto err_misc;
3640 }
3641
3642 ret = register_netdevice_notifier(&tun_notifier_block);
3643 if (ret) {
3644 pr_err("Can't register netdevice notifier\n");
3645 goto err_notifier;
3646 }
3647
3648 return 0;
3649
3650 err_notifier:
3651 misc_deregister(&tun_miscdev);
3652 err_misc:
3653 rtnl_link_unregister(&tun_link_ops);
3654 err_linkops:
3655 return ret;
3656 }
3657
3658 static void tun_cleanup(void)
3659 {
3660 misc_deregister(&tun_miscdev);
3661 rtnl_link_unregister(&tun_link_ops);
3662 unregister_netdevice_notifier(&tun_notifier_block);
3663 }
3664
3665 /* Get an underlying socket object from tun file. Returns error unless file is
3666 * attached to a device. The returned object works like a packet socket, it
3667 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
3668 * holding a reference to the file for as long as the socket is in use. */
3669 struct socket *tun_get_socket(struct file *file)
3670 {
3671 struct tun_file *tfile;
3672 if (file->f_op != &tun_fops)
3673 return ERR_PTR(-EINVAL);
3674 tfile = file->private_data;
3675 if (!tfile)
3676 return ERR_PTR(-EBADFD);
3677 return &tfile->socket;
3678 }
3679 EXPORT_SYMBOL_GPL(tun_get_socket);
3680
3681 struct ptr_ring *tun_get_tx_ring(struct file *file)
3682 {
3683 struct tun_file *tfile;
3684
3685 if (file->f_op != &tun_fops)
3686 return ERR_PTR(-EINVAL);
3687 tfile = file->private_data;
3688 if (!tfile)
3689 return ERR_PTR(-EBADFD);
3690 return &tfile->tx_ring;
3691 }
3692 EXPORT_SYMBOL_GPL(tun_get_tx_ring);
3693
3694 module_init(tun_init);
3695 module_exit(tun_cleanup);
3696 MODULE_DESCRIPTION(DRV_DESCRIPTION);
3697 MODULE_AUTHOR(DRV_COPYRIGHT);
3698 MODULE_LICENSE("GPL");
3699 MODULE_ALIAS_MISCDEV(TUN_MINOR);
3700 MODULE_ALIAS("devname:net/tun");
Linux with added FPC-III support