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Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
[cris-mirror.git] / drivers / net / tun.c
blob7433bb2e4451636778460d22f18cc0a63e5468be
1 /*
2 * TUN - Universal TUN/TAP device driver.
3 * Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
16 */
17
18 /*
19 * Changes:
20 *
21 * Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
22 * Add TUNSETLINK ioctl to set the link encapsulation
23 *
24 * Mark Smith <markzzzsmith@yahoo.com.au>
25 * Use eth_random_addr() for tap MAC address.
26 *
27 * Harald Roelle <harald.roelle@ifi.lmu.de> 2004/04/20
28 * Fixes in packet dropping, queue length setting and queue wakeup.
29 * Increased default tx queue length.
30 * Added ethtool API.
31 * Minor cleanups
32 *
33 * Daniel Podlejski <underley@underley.eu.org>
34 * Modifications for 2.3.99-pre5 kernel.
35 */
36
37 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
38
39 #define DRV_NAME "tun"
40 #define DRV_VERSION "1.6"
41 #define DRV_DESCRIPTION "Universal TUN/TAP device driver"
42 #define DRV_COPYRIGHT "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
43
44 #include <linux/module.h>
45 #include <linux/errno.h>
46 #include <linux/kernel.h>
47 #include <linux/sched/signal.h>
48 #include <linux/major.h>
49 #include <linux/slab.h>
50 #include <linux/poll.h>
51 #include <linux/fcntl.h>
52 #include <linux/init.h>
53 #include <linux/skbuff.h>
54 #include <linux/netdevice.h>
55 #include <linux/etherdevice.h>
56 #include <linux/miscdevice.h>
57 #include <linux/ethtool.h>
58 #include <linux/rtnetlink.h>
59 #include <linux/compat.h>
60 #include <linux/if.h>
61 #include <linux/if_arp.h>
62 #include <linux/if_ether.h>
63 #include <linux/if_tun.h>
64 #include <linux/if_vlan.h>
65 #include <linux/crc32.h>
66 #include <linux/nsproxy.h>
67 #include <linux/virtio_net.h>
68 #include <linux/rcupdate.h>
69 #include <net/net_namespace.h>
70 #include <net/netns/generic.h>
71 #include <net/rtnetlink.h>
72 #include <net/sock.h>
73 #include <linux/seq_file.h>
74 #include <linux/uio.h>
75 #include <linux/skb_array.h>
76 #include <linux/bpf.h>
77 #include <linux/bpf_trace.h>
78 #include <linux/mutex.h>
79
80 #include <linux/uaccess.h>
81
82 /* Uncomment to enable debugging */
83 /* #define TUN_DEBUG 1 */
84
85 #ifdef TUN_DEBUG
86 static int debug;
87
88 #define tun_debug(level, tun, fmt, args...) \
89 do { \
90 if (tun->debug) \
91 netdev_printk(level, tun->dev, fmt, ##args); \
92 } while (0)
93 #define DBG1(level, fmt, args...) \
94 do { \
95 if (debug == 2) \
96 printk(level fmt, ##args); \
97 } while (0)
98 #else
99 #define tun_debug(level, tun, fmt, args...) \
100 do { \
101 if (0) \
102 netdev_printk(level, tun->dev, fmt, ##args); \
103 } while (0)
104 #define DBG1(level, fmt, args...) \
105 do { \
106 if (0) \
107 printk(level fmt, ##args); \
108 } while (0)
109 #endif
110
111 #define TUN_HEADROOM 256
112 #define TUN_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
113
114 /* TUN device flags */
115
116 /* IFF_ATTACH_QUEUE is never stored in device flags,
117 * overload it to mean fasync when stored there.
118 */
119 #define TUN_FASYNC IFF_ATTACH_QUEUE
120 /* High bits in flags field are unused. */
121 #define TUN_VNET_LE 0x80000000
122 #define TUN_VNET_BE 0x40000000
123
124 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
125 IFF_MULTI_QUEUE | IFF_NAPI | IFF_NAPI_FRAGS)
126
127 #define GOODCOPY_LEN 128
128
129 #define FLT_EXACT_COUNT 8
130 struct tap_filter {
131 unsigned int count; /* Number of addrs. Zero means disabled */
132 u32 mask[2]; /* Mask of the hashed addrs */
133 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
134 };
135
136 /* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
137 * to max number of VCPUs in guest. */
138 #define MAX_TAP_QUEUES 256
139 #define MAX_TAP_FLOWS 4096
140
141 #define TUN_FLOW_EXPIRE (3 * HZ)
142
143 struct tun_pcpu_stats {
144 u64 rx_packets;
145 u64 rx_bytes;
146 u64 tx_packets;
147 u64 tx_bytes;
148 struct u64_stats_sync syncp;
149 u32 rx_dropped;
150 u32 tx_dropped;
151 u32 rx_frame_errors;
152 };
153
154 /* A tun_file connects an open character device to a tuntap netdevice. It
155 * also contains all socket related structures (except sock_fprog and tap_filter)
156 * to serve as one transmit queue for tuntap device. The sock_fprog and
157 * tap_filter were kept in tun_struct since they were used for filtering for the
158 * netdevice not for a specific queue (at least I didn't see the requirement for
159 * this).
160 *
161 * RCU usage:
162 * The tun_file and tun_struct are loosely coupled, the pointer from one to the
163 * other can only be read while rcu_read_lock or rtnl_lock is held.
164 */
165 struct tun_file {
166 struct sock sk;
167 struct socket socket;
168 struct socket_wq wq;
169 struct tun_struct __rcu *tun;
170 struct fasync_struct *fasync;
171 /* only used for fasnyc */
172 unsigned int flags;
173 union {
174 u16 queue_index;
175 unsigned int ifindex;
176 };
177 struct napi_struct napi;
178 bool napi_enabled;
179 struct mutex napi_mutex; /* Protects access to the above napi */
180 struct list_head next;
181 struct tun_struct *detached;
182 struct ptr_ring tx_ring;
183 struct xdp_rxq_info xdp_rxq;
184 };
185
186 struct tun_flow_entry {
187 struct hlist_node hash_link;
188 struct rcu_head rcu;
189 struct tun_struct *tun;
190
191 u32 rxhash;
192 u32 rps_rxhash;
193 int queue_index;
194 unsigned long updated;
195 };
196
197 #define TUN_NUM_FLOW_ENTRIES 1024
198
199 struct tun_prog {
200 struct rcu_head rcu;
201 struct bpf_prog *prog;
202 };
203
204 /* Since the socket were moved to tun_file, to preserve the behavior of persist
205 * device, socket filter, sndbuf and vnet header size were restore when the
206 * file were attached to a persist device.
207 */
208 struct tun_struct {
209 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES];
210 unsigned int numqueues;
211 unsigned int flags;
212 kuid_t owner;
213 kgid_t group;
214
215 struct net_device *dev;
216 netdev_features_t set_features;
217 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
218 NETIF_F_TSO6)
219
220 int align;
221 int vnet_hdr_sz;
222 int sndbuf;
223 struct tap_filter txflt;
224 struct sock_fprog fprog;
225 /* protected by rtnl lock */
226 bool filter_attached;
227 #ifdef TUN_DEBUG
228 int debug;
229 #endif
230 spinlock_t lock;
231 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
232 struct timer_list flow_gc_timer;
233 unsigned long ageing_time;
234 unsigned int numdisabled;
235 struct list_head disabled;
236 void *security;
237 u32 flow_count;
238 u32 rx_batched;
239 struct tun_pcpu_stats __percpu *pcpu_stats;
240 struct bpf_prog __rcu *xdp_prog;
241 struct tun_prog __rcu *steering_prog;
242 struct tun_prog __rcu *filter_prog;
243 };
244
245 struct veth {
246 __be16 h_vlan_proto;
247 __be16 h_vlan_TCI;
248 };
249
250 bool tun_is_xdp_buff(void *ptr)
251 {
252 return (unsigned long)ptr & TUN_XDP_FLAG;
253 }
254 EXPORT_SYMBOL(tun_is_xdp_buff);
255
256 void *tun_xdp_to_ptr(void *ptr)
257 {
258 return (void *)((unsigned long)ptr | TUN_XDP_FLAG);
259 }
260 EXPORT_SYMBOL(tun_xdp_to_ptr);
261
262 void *tun_ptr_to_xdp(void *ptr)
263 {
264 return (void *)((unsigned long)ptr & ~TUN_XDP_FLAG);
265 }
266 EXPORT_SYMBOL(tun_ptr_to_xdp);
267
268 static int tun_napi_receive(struct napi_struct *napi, int budget)
269 {
270 struct tun_file *tfile = container_of(napi, struct tun_file, napi);
271 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
272 struct sk_buff_head process_queue;
273 struct sk_buff *skb;
274 int received = 0;
275
276 __skb_queue_head_init(&process_queue);
277
278 spin_lock(&queue->lock);
279 skb_queue_splice_tail_init(queue, &process_queue);
280 spin_unlock(&queue->lock);
281
282 while (received < budget && (skb = __skb_dequeue(&process_queue))) {
283 napi_gro_receive(napi, skb);
284 ++received;
285 }
286
287 if (!skb_queue_empty(&process_queue)) {
288 spin_lock(&queue->lock);
289 skb_queue_splice(&process_queue, queue);
290 spin_unlock(&queue->lock);
291 }
292
293 return received;
294 }
295
296 static int tun_napi_poll(struct napi_struct *napi, int budget)
297 {
298 unsigned int received;
299
300 received = tun_napi_receive(napi, budget);
301
302 if (received < budget)
303 napi_complete_done(napi, received);
304
305 return received;
306 }
307
308 static void tun_napi_init(struct tun_struct *tun, struct tun_file *tfile,
309 bool napi_en)
310 {
311 tfile->napi_enabled = napi_en;
312 if (napi_en) {
313 netif_napi_add(tun->dev, &tfile->napi, tun_napi_poll,
314 NAPI_POLL_WEIGHT);
315 napi_enable(&tfile->napi);
316 mutex_init(&tfile->napi_mutex);
317 }
318 }
319
320 static void tun_napi_disable(struct tun_struct *tun, struct tun_file *tfile)
321 {
322 if (tfile->napi_enabled)
323 napi_disable(&tfile->napi);
324 }
325
326 static void tun_napi_del(struct tun_struct *tun, struct tun_file *tfile)
327 {
328 if (tfile->napi_enabled)
329 netif_napi_del(&tfile->napi);
330 }
331
332 static bool tun_napi_frags_enabled(const struct tun_struct *tun)
333 {
334 return READ_ONCE(tun->flags) & IFF_NAPI_FRAGS;
335 }
336
337 #ifdef CONFIG_TUN_VNET_CROSS_LE
338 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
339 {
340 return tun->flags & TUN_VNET_BE ? false :
341 virtio_legacy_is_little_endian();
342 }
343
344 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
345 {
346 int be = !!(tun->flags & TUN_VNET_BE);
347
348 if (put_user(be, argp))
349 return -EFAULT;
350
351 return 0;
352 }
353
354 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
355 {
356 int be;
357
358 if (get_user(be, argp))
359 return -EFAULT;
360
361 if (be)
362 tun->flags |= TUN_VNET_BE;
363 else
364 tun->flags &= ~TUN_VNET_BE;
365
366 return 0;
367 }
368 #else
369 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
370 {
371 return virtio_legacy_is_little_endian();
372 }
373
374 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
375 {
376 return -EINVAL;
377 }
378
379 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
380 {
381 return -EINVAL;
382 }
383 #endif /* CONFIG_TUN_VNET_CROSS_LE */
384
385 static inline bool tun_is_little_endian(struct tun_struct *tun)
386 {
387 return tun->flags & TUN_VNET_LE ||
388 tun_legacy_is_little_endian(tun);
389 }
390
391 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
392 {
393 return __virtio16_to_cpu(tun_is_little_endian(tun), val);
394 }
395
396 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
397 {
398 return __cpu_to_virtio16(tun_is_little_endian(tun), val);
399 }
400
401 static inline u32 tun_hashfn(u32 rxhash)
402 {
403 return rxhash & 0x3ff;
404 }
405
406 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
407 {
408 struct tun_flow_entry *e;
409
410 hlist_for_each_entry_rcu(e, head, hash_link) {
411 if (e->rxhash == rxhash)
412 return e;
413 }
414 return NULL;
415 }
416
417 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
418 struct hlist_head *head,
419 u32 rxhash, u16 queue_index)
420 {
421 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
422
423 if (e) {
424 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
425 rxhash, queue_index);
426 e->updated = jiffies;
427 e->rxhash = rxhash;
428 e->rps_rxhash = 0;
429 e->queue_index = queue_index;
430 e->tun = tun;
431 hlist_add_head_rcu(&e->hash_link, head);
432 ++tun->flow_count;
433 }
434 return e;
435 }
436
437 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
438 {
439 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
440 e->rxhash, e->queue_index);
441 hlist_del_rcu(&e->hash_link);
442 kfree_rcu(e, rcu);
443 --tun->flow_count;
444 }
445
446 static void tun_flow_flush(struct tun_struct *tun)
447 {
448 int i;
449
450 spin_lock_bh(&tun->lock);
451 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
452 struct tun_flow_entry *e;
453 struct hlist_node *n;
454
455 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
456 tun_flow_delete(tun, e);
457 }
458 spin_unlock_bh(&tun->lock);
459 }
460
461 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
462 {
463 int i;
464
465 spin_lock_bh(&tun->lock);
466 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
467 struct tun_flow_entry *e;
468 struct hlist_node *n;
469
470 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
471 if (e->queue_index == queue_index)
472 tun_flow_delete(tun, e);
473 }
474 }
475 spin_unlock_bh(&tun->lock);
476 }
477
478 static void tun_flow_cleanup(struct timer_list *t)
479 {
480 struct tun_struct *tun = from_timer(tun, t, flow_gc_timer);
481 unsigned long delay = tun->ageing_time;
482 unsigned long next_timer = jiffies + delay;
483 unsigned long count = 0;
484 int i;
485
486 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
487
488 spin_lock(&tun->lock);
489 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
490 struct tun_flow_entry *e;
491 struct hlist_node *n;
492
493 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
494 unsigned long this_timer;
495
496 this_timer = e->updated + delay;
497 if (time_before_eq(this_timer, jiffies)) {
498 tun_flow_delete(tun, e);
499 continue;
500 }
501 count++;
502 if (time_before(this_timer, next_timer))
503 next_timer = this_timer;
504 }
505 }
506
507 if (count)
508 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
509 spin_unlock(&tun->lock);
510 }
511
512 static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
513 struct tun_file *tfile)
514 {
515 struct hlist_head *head;
516 struct tun_flow_entry *e;
517 unsigned long delay = tun->ageing_time;
518 u16 queue_index = tfile->queue_index;
519
520 if (!rxhash)
521 return;
522 else
523 head = &tun->flows[tun_hashfn(rxhash)];
524
525 rcu_read_lock();
526
527 /* We may get a very small possibility of OOO during switching, not
528 * worth to optimize.*/
529 if (tun->numqueues == 1 || tfile->detached)
530 goto unlock;
531
532 e = tun_flow_find(head, rxhash);
533 if (likely(e)) {
534 /* TODO: keep queueing to old queue until it's empty? */
535 e->queue_index = queue_index;
536 e->updated = jiffies;
537 sock_rps_record_flow_hash(e->rps_rxhash);
538 } else {
539 spin_lock_bh(&tun->lock);
540 if (!tun_flow_find(head, rxhash) &&
541 tun->flow_count < MAX_TAP_FLOWS)
542 tun_flow_create(tun, head, rxhash, queue_index);
543
544 if (!timer_pending(&tun->flow_gc_timer))
545 mod_timer(&tun->flow_gc_timer,
546 round_jiffies_up(jiffies + delay));
547 spin_unlock_bh(&tun->lock);
548 }
549
550 unlock:
551 rcu_read_unlock();
552 }
553
554 /**
555 * Save the hash received in the stack receive path and update the
556 * flow_hash table accordingly.
557 */
558 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
559 {
560 if (unlikely(e->rps_rxhash != hash))
561 e->rps_rxhash = hash;
562 }
563
564 /* We try to identify a flow through its rxhash first. The reason that
565 * we do not check rxq no. is because some cards(e.g 82599), chooses
566 * the rxq based on the txq where the last packet of the flow comes. As
567 * the userspace application move between processors, we may get a
568 * different rxq no. here. If we could not get rxhash, then we would
569 * hope the rxq no. may help here.
570 */
571 static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb)
572 {
573 struct tun_flow_entry *e;
574 u32 txq = 0;
575 u32 numqueues = 0;
576
577 numqueues = READ_ONCE(tun->numqueues);
578
579 txq = __skb_get_hash_symmetric(skb);
580 if (txq) {
581 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
582 if (e) {
583 tun_flow_save_rps_rxhash(e, txq);
584 txq = e->queue_index;
585 } else
586 /* use multiply and shift instead of expensive divide */
587 txq = ((u64)txq * numqueues) >> 32;
588 } else if (likely(skb_rx_queue_recorded(skb))) {
589 txq = skb_get_rx_queue(skb);
590 while (unlikely(txq >= numqueues))
591 txq -= numqueues;
592 }
593
594 return txq;
595 }
596
597 static u16 tun_ebpf_select_queue(struct tun_struct *tun, struct sk_buff *skb)
598 {
599 struct tun_prog *prog;
600 u16 ret = 0;
601
602 prog = rcu_dereference(tun->steering_prog);
603 if (prog)
604 ret = bpf_prog_run_clear_cb(prog->prog, skb);
605
606 return ret % tun->numqueues;
607 }
608
609 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
610 void *accel_priv, select_queue_fallback_t fallback)
611 {
612 struct tun_struct *tun = netdev_priv(dev);
613 u16 ret;
614
615 rcu_read_lock();
616 if (rcu_dereference(tun->steering_prog))
617 ret = tun_ebpf_select_queue(tun, skb);
618 else
619 ret = tun_automq_select_queue(tun, skb);
620 rcu_read_unlock();
621
622 return ret;
623 }
624
625 static inline bool tun_not_capable(struct tun_struct *tun)
626 {
627 const struct cred *cred = current_cred();
628 struct net *net = dev_net(tun->dev);
629
630 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
631 (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
632 !ns_capable(net->user_ns, CAP_NET_ADMIN);
633 }
634
635 static void tun_set_real_num_queues(struct tun_struct *tun)
636 {
637 netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
638 netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
639 }
640
641 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
642 {
643 tfile->detached = tun;
644 list_add_tail(&tfile->next, &tun->disabled);
645 ++tun->numdisabled;
646 }
647
648 static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
649 {
650 struct tun_struct *tun = tfile->detached;
651
652 tfile->detached = NULL;
653 list_del_init(&tfile->next);
654 --tun->numdisabled;
655 return tun;
656 }
657
658 static void tun_ptr_free(void *ptr)
659 {
660 if (!ptr)
661 return;
662 if (tun_is_xdp_buff(ptr)) {
663 struct xdp_buff *xdp = tun_ptr_to_xdp(ptr);
664
665 put_page(virt_to_head_page(xdp->data));
666 } else {
667 __skb_array_destroy_skb(ptr);
668 }
669 }
670
671 static void tun_queue_purge(struct tun_file *tfile)
672 {
673 void *ptr;
674
675 while ((ptr = ptr_ring_consume(&tfile->tx_ring)) != NULL)
676 tun_ptr_free(ptr);
677
678 skb_queue_purge(&tfile->sk.sk_write_queue);
679 skb_queue_purge(&tfile->sk.sk_error_queue);
680 }
681
682 static void tun_cleanup_tx_ring(struct tun_file *tfile)
683 {
684 if (tfile->tx_ring.queue) {
685 ptr_ring_cleanup(&tfile->tx_ring, tun_ptr_free);
686 xdp_rxq_info_unreg(&tfile->xdp_rxq);
687 memset(&tfile->tx_ring, 0, sizeof(tfile->tx_ring));
688 }
689 }
690
691 static void __tun_detach(struct tun_file *tfile, bool clean)
692 {
693 struct tun_file *ntfile;
694 struct tun_struct *tun;
695
696 tun = rtnl_dereference(tfile->tun);
697
698 if (tun && clean) {
699 tun_napi_disable(tun, tfile);
700 tun_napi_del(tun, tfile);
701 }
702
703 if (tun && !tfile->detached) {
704 u16 index = tfile->queue_index;
705 BUG_ON(index >= tun->numqueues);
706
707 rcu_assign_pointer(tun->tfiles[index],
708 tun->tfiles[tun->numqueues - 1]);
709 ntfile = rtnl_dereference(tun->tfiles[index]);
710 ntfile->queue_index = index;
711
712 --tun->numqueues;
713 if (clean) {
714 RCU_INIT_POINTER(tfile->tun, NULL);
715 sock_put(&tfile->sk);
716 } else
717 tun_disable_queue(tun, tfile);
718
719 synchronize_net();
720 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
721 /* Drop read queue */
722 tun_queue_purge(tfile);
723 tun_set_real_num_queues(tun);
724 } else if (tfile->detached && clean) {
725 tun = tun_enable_queue(tfile);
726 sock_put(&tfile->sk);
727 }
728
729 if (clean) {
730 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
731 netif_carrier_off(tun->dev);
732
733 if (!(tun->flags & IFF_PERSIST) &&
734 tun->dev->reg_state == NETREG_REGISTERED)
735 unregister_netdevice(tun->dev);
736 }
737 tun_cleanup_tx_ring(tfile);
738 sock_put(&tfile->sk);
739 }
740 }
741
742 static void tun_detach(struct tun_file *tfile, bool clean)
743 {
744 rtnl_lock();
745 __tun_detach(tfile, clean);
746 rtnl_unlock();
747 }
748
749 static void tun_detach_all(struct net_device *dev)
750 {
751 struct tun_struct *tun = netdev_priv(dev);
752 struct tun_file *tfile, *tmp;
753 int i, n = tun->numqueues;
754
755 for (i = 0; i < n; i++) {
756 tfile = rtnl_dereference(tun->tfiles[i]);
757 BUG_ON(!tfile);
758 tun_napi_disable(tun, tfile);
759 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
760 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
761 RCU_INIT_POINTER(tfile->tun, NULL);
762 --tun->numqueues;
763 }
764 list_for_each_entry(tfile, &tun->disabled, next) {
765 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
766 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
767 RCU_INIT_POINTER(tfile->tun, NULL);
768 }
769 BUG_ON(tun->numqueues != 0);
770
771 synchronize_net();
772 for (i = 0; i < n; i++) {
773 tfile = rtnl_dereference(tun->tfiles[i]);
774 tun_napi_del(tun, tfile);
775 /* Drop read queue */
776 tun_queue_purge(tfile);
777 sock_put(&tfile->sk);
778 tun_cleanup_tx_ring(tfile);
779 }
780 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
781 tun_enable_queue(tfile);
782 tun_queue_purge(tfile);
783 sock_put(&tfile->sk);
784 tun_cleanup_tx_ring(tfile);
785 }
786 BUG_ON(tun->numdisabled != 0);
787
788 if (tun->flags & IFF_PERSIST)
789 module_put(THIS_MODULE);
790 }
791
792 static int tun_attach(struct tun_struct *tun, struct file *file,
793 bool skip_filter, bool napi)
794 {
795 struct tun_file *tfile = file->private_data;
796 struct net_device *dev = tun->dev;
797 int err;
798
799 err = security_tun_dev_attach(tfile->socket.sk, tun->security);
800 if (err < 0)
801 goto out;
802
803 err = -EINVAL;
804 if (rtnl_dereference(tfile->tun) && !tfile->detached)
805 goto out;
806
807 err = -EBUSY;
808 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
809 goto out;
810
811 err = -E2BIG;
812 if (!tfile->detached &&
813 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
814 goto out;
815
816 err = 0;
817
818 /* Re-attach the filter to persist device */
819 if (!skip_filter && (tun->filter_attached == true)) {
820 lock_sock(tfile->socket.sk);
821 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
822 release_sock(tfile->socket.sk);
823 if (!err)
824 goto out;
825 }
826
827 if (!tfile->detached &&
828 ptr_ring_init(&tfile->tx_ring, dev->tx_queue_len, GFP_KERNEL)) {
829 err = -ENOMEM;
830 goto out;
831 }
832
833 tfile->queue_index = tun->numqueues;
834 tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
835
836 if (tfile->detached) {
837 /* Re-attach detached tfile, updating XDP queue_index */
838 WARN_ON(!xdp_rxq_info_is_reg(&tfile->xdp_rxq));
839
840 if (tfile->xdp_rxq.queue_index != tfile->queue_index)
841 tfile->xdp_rxq.queue_index = tfile->queue_index;
842 } else {
843 /* Setup XDP RX-queue info, for new tfile getting attached */
844 err = xdp_rxq_info_reg(&tfile->xdp_rxq,
845 tun->dev, tfile->queue_index);
846 if (err < 0)
847 goto out;
848 err = 0;
849 }
850
851 rcu_assign_pointer(tfile->tun, tun);
852 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
853 tun->numqueues++;
854
855 if (tfile->detached) {
856 tun_enable_queue(tfile);
857 } else {
858 sock_hold(&tfile->sk);
859 tun_napi_init(tun, tfile, napi);
860 }
861
862 tun_set_real_num_queues(tun);
863
864 /* device is allowed to go away first, so no need to hold extra
865 * refcnt.
866 */
867
868 out:
869 return err;
870 }
871
872 static struct tun_struct *tun_get(struct tun_file *tfile)
873 {
874 struct tun_struct *tun;
875
876 rcu_read_lock();
877 tun = rcu_dereference(tfile->tun);
878 if (tun)
879 dev_hold(tun->dev);
880 rcu_read_unlock();
881
882 return tun;
883 }
884
885 static void tun_put(struct tun_struct *tun)
886 {
887 dev_put(tun->dev);
888 }
889
890 /* TAP filtering */
891 static void addr_hash_set(u32 *mask, const u8 *addr)
892 {
893 int n = ether_crc(ETH_ALEN, addr) >> 26;
894 mask[n >> 5] |= (1 << (n & 31));
895 }
896
897 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
898 {
899 int n = ether_crc(ETH_ALEN, addr) >> 26;
900 return mask[n >> 5] & (1 << (n & 31));
901 }
902
903 static int update_filter(struct tap_filter *filter, void __user *arg)
904 {
905 struct { u8 u[ETH_ALEN]; } *addr;
906 struct tun_filter uf;
907 int err, alen, n, nexact;
908
909 if (copy_from_user(&uf, arg, sizeof(uf)))
910 return -EFAULT;
911
912 if (!uf.count) {
913 /* Disabled */
914 filter->count = 0;
915 return 0;
916 }
917
918 alen = ETH_ALEN * uf.count;
919 addr = memdup_user(arg + sizeof(uf), alen);
920 if (IS_ERR(addr))
921 return PTR_ERR(addr);
922
923 /* The filter is updated without holding any locks. Which is
924 * perfectly safe. We disable it first and in the worst
925 * case we'll accept a few undesired packets. */
926 filter->count = 0;
927 wmb();
928
929 /* Use first set of addresses as an exact filter */
930 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
931 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
932
933 nexact = n;
934
935 /* Remaining multicast addresses are hashed,
936 * unicast will leave the filter disabled. */
937 memset(filter->mask, 0, sizeof(filter->mask));
938 for (; n < uf.count; n++) {
939 if (!is_multicast_ether_addr(addr[n].u)) {
940 err = 0; /* no filter */
941 goto free_addr;
942 }
943 addr_hash_set(filter->mask, addr[n].u);
944 }
945
946 /* For ALLMULTI just set the mask to all ones.
947 * This overrides the mask populated above. */
948 if ((uf.flags & TUN_FLT_ALLMULTI))
949 memset(filter->mask, ~0, sizeof(filter->mask));
950
951 /* Now enable the filter */
952 wmb();
953 filter->count = nexact;
954
955 /* Return the number of exact filters */
956 err = nexact;
957 free_addr:
958 kfree(addr);
959 return err;
960 }
961
962 /* Returns: 0 - drop, !=0 - accept */
963 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
964 {
965 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
966 * at this point. */
967 struct ethhdr *eh = (struct ethhdr *) skb->data;
968 int i;
969
970 /* Exact match */
971 for (i = 0; i < filter->count; i++)
972 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
973 return 1;
974
975 /* Inexact match (multicast only) */
976 if (is_multicast_ether_addr(eh->h_dest))
977 return addr_hash_test(filter->mask, eh->h_dest);
978
979 return 0;
980 }
981
982 /*
983 * Checks whether the packet is accepted or not.
984 * Returns: 0 - drop, !=0 - accept
985 */
986 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
987 {
988 if (!filter->count)
989 return 1;
990
991 return run_filter(filter, skb);
992 }
993
994 /* Network device part of the driver */
995
996 static const struct ethtool_ops tun_ethtool_ops;
997
998 /* Net device detach from fd. */
999 static void tun_net_uninit(struct net_device *dev)
1000 {
1001 tun_detach_all(dev);
1002 }
1003
1004 /* Net device open. */
1005 static int tun_net_open(struct net_device *dev)
1006 {
1007 struct tun_struct *tun = netdev_priv(dev);
1008 int i;
1009
1010 netif_tx_start_all_queues(dev);
1011
1012 for (i = 0; i < tun->numqueues; i++) {
1013 struct tun_file *tfile;
1014
1015 tfile = rtnl_dereference(tun->tfiles[i]);
1016 tfile->socket.sk->sk_write_space(tfile->socket.sk);
1017 }
1018
1019 return 0;
1020 }
1021
1022 /* Net device close. */
1023 static int tun_net_close(struct net_device *dev)
1024 {
1025 netif_tx_stop_all_queues(dev);
1026 return 0;
1027 }
1028
1029 /* Net device start xmit */
1030 static void tun_automq_xmit(struct tun_struct *tun, struct sk_buff *skb)
1031 {
1032 #ifdef CONFIG_RPS
1033 if (tun->numqueues == 1 && static_key_false(&rps_needed)) {
1034 /* Select queue was not called for the skbuff, so we extract the
1035 * RPS hash and save it into the flow_table here.
1036 */
1037 __u32 rxhash;
1038
1039 rxhash = __skb_get_hash_symmetric(skb);
1040 if (rxhash) {
1041 struct tun_flow_entry *e;
1042 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)],
1043 rxhash);
1044 if (e)
1045 tun_flow_save_rps_rxhash(e, rxhash);
1046 }
1047 }
1048 #endif
1049 }
1050
1051 static unsigned int run_ebpf_filter(struct tun_struct *tun,
1052 struct sk_buff *skb,
1053 int len)
1054 {
1055 struct tun_prog *prog = rcu_dereference(tun->filter_prog);
1056
1057 if (prog)
1058 len = bpf_prog_run_clear_cb(prog->prog, skb);
1059
1060 return len;
1061 }
1062
1063 /* Net device start xmit */
1064 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
1065 {
1066 struct tun_struct *tun = netdev_priv(dev);
1067 int txq = skb->queue_mapping;
1068 struct tun_file *tfile;
1069 int len = skb->len;
1070
1071 rcu_read_lock();
1072 tfile = rcu_dereference(tun->tfiles[txq]);
1073
1074 /* Drop packet if interface is not attached */
1075 if (txq >= tun->numqueues)
1076 goto drop;
1077
1078 if (!rcu_dereference(tun->steering_prog))
1079 tun_automq_xmit(tun, skb);
1080
1081 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
1082
1083 BUG_ON(!tfile);
1084
1085 /* Drop if the filter does not like it.
1086 * This is a noop if the filter is disabled.
1087 * Filter can be enabled only for the TAP devices. */
1088 if (!check_filter(&tun->txflt, skb))
1089 goto drop;
1090
1091 if (tfile->socket.sk->sk_filter &&
1092 sk_filter(tfile->socket.sk, skb))
1093 goto drop;
1094
1095 len = run_ebpf_filter(tun, skb, len);
1096
1097 /* Trim extra bytes since we may insert vlan proto & TCI
1098 * in tun_put_user().
1099 */
1100 len -= skb_vlan_tag_present(skb) ? sizeof(struct veth) : 0;
1101 if (len <= 0 || pskb_trim(skb, len))
1102 goto drop;
1103
1104 if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC)))
1105 goto drop;
1106
1107 skb_tx_timestamp(skb);
1108
1109 /* Orphan the skb - required as we might hang on to it
1110 * for indefinite time.
1111 */
1112 skb_orphan(skb);
1113
1114 nf_reset(skb);
1115
1116 if (ptr_ring_produce(&tfile->tx_ring, skb))
1117 goto drop;
1118
1119 /* Notify and wake up reader process */
1120 if (tfile->flags & TUN_FASYNC)
1121 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1122 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1123
1124 rcu_read_unlock();
1125 return NETDEV_TX_OK;
1126
1127 drop:
1128 this_cpu_inc(tun->pcpu_stats->tx_dropped);
1129 skb_tx_error(skb);
1130 kfree_skb(skb);
1131 rcu_read_unlock();
1132 return NET_XMIT_DROP;
1133 }
1134
1135 static void tun_net_mclist(struct net_device *dev)
1136 {
1137 /*
1138 * This callback is supposed to deal with mc filter in
1139 * _rx_ path and has nothing to do with the _tx_ path.
1140 * In rx path we always accept everything userspace gives us.
1141 */
1142 }
1143
1144 static netdev_features_t tun_net_fix_features(struct net_device *dev,
1145 netdev_features_t features)
1146 {
1147 struct tun_struct *tun = netdev_priv(dev);
1148
1149 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
1150 }
1151 #ifdef CONFIG_NET_POLL_CONTROLLER
1152 static void tun_poll_controller(struct net_device *dev)
1153 {
1154 /*
1155 * Tun only receives frames when:
1156 * 1) the char device endpoint gets data from user space
1157 * 2) the tun socket gets a sendmsg call from user space
1158 * If NAPI is not enabled, since both of those are synchronous
1159 * operations, we are guaranteed never to have pending data when we poll
1160 * for it so there is nothing to do here but return.
1161 * We need this though so netpoll recognizes us as an interface that
1162 * supports polling, which enables bridge devices in virt setups to
1163 * still use netconsole
1164 * If NAPI is enabled, however, we need to schedule polling for all
1165 * queues unless we are using napi_gro_frags(), which we call in
1166 * process context and not in NAPI context.
1167 */
1168 struct tun_struct *tun = netdev_priv(dev);
1169
1170 if (tun->flags & IFF_NAPI) {
1171 struct tun_file *tfile;
1172 int i;
1173
1174 if (tun_napi_frags_enabled(tun))
1175 return;
1176
1177 rcu_read_lock();
1178 for (i = 0; i < tun->numqueues; i++) {
1179 tfile = rcu_dereference(tun->tfiles[i]);
1180 if (tfile->napi_enabled)
1181 napi_schedule(&tfile->napi);
1182 }
1183 rcu_read_unlock();
1184 }
1185 return;
1186 }
1187 #endif
1188
1189 static void tun_set_headroom(struct net_device *dev, int new_hr)
1190 {
1191 struct tun_struct *tun = netdev_priv(dev);
1192
1193 if (new_hr < NET_SKB_PAD)
1194 new_hr = NET_SKB_PAD;
1195
1196 tun->align = new_hr;
1197 }
1198
1199 static void
1200 tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
1201 {
1202 u32 rx_dropped = 0, tx_dropped = 0, rx_frame_errors = 0;
1203 struct tun_struct *tun = netdev_priv(dev);
1204 struct tun_pcpu_stats *p;
1205 int i;
1206
1207 for_each_possible_cpu(i) {
1208 u64 rxpackets, rxbytes, txpackets, txbytes;
1209 unsigned int start;
1210
1211 p = per_cpu_ptr(tun->pcpu_stats, i);
1212 do {
1213 start = u64_stats_fetch_begin(&p->syncp);
1214 rxpackets = p->rx_packets;
1215 rxbytes = p->rx_bytes;
1216 txpackets = p->tx_packets;
1217 txbytes = p->tx_bytes;
1218 } while (u64_stats_fetch_retry(&p->syncp, start));
1219
1220 stats->rx_packets += rxpackets;
1221 stats->rx_bytes += rxbytes;
1222 stats->tx_packets += txpackets;
1223 stats->tx_bytes += txbytes;
1224
1225 /* u32 counters */
1226 rx_dropped += p->rx_dropped;
1227 rx_frame_errors += p->rx_frame_errors;
1228 tx_dropped += p->tx_dropped;
1229 }
1230 stats->rx_dropped = rx_dropped;
1231 stats->rx_frame_errors = rx_frame_errors;
1232 stats->tx_dropped = tx_dropped;
1233 }
1234
1235 static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1236 struct netlink_ext_ack *extack)
1237 {
1238 struct tun_struct *tun = netdev_priv(dev);
1239 struct bpf_prog *old_prog;
1240
1241 old_prog = rtnl_dereference(tun->xdp_prog);
1242 rcu_assign_pointer(tun->xdp_prog, prog);
1243 if (old_prog)
1244 bpf_prog_put(old_prog);
1245
1246 return 0;
1247 }
1248
1249 static u32 tun_xdp_query(struct net_device *dev)
1250 {
1251 struct tun_struct *tun = netdev_priv(dev);
1252 const struct bpf_prog *xdp_prog;
1253
1254 xdp_prog = rtnl_dereference(tun->xdp_prog);
1255 if (xdp_prog)
1256 return xdp_prog->aux->id;
1257
1258 return 0;
1259 }
1260
1261 static int tun_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1262 {
1263 switch (xdp->command) {
1264 case XDP_SETUP_PROG:
1265 return tun_xdp_set(dev, xdp->prog, xdp->extack);
1266 case XDP_QUERY_PROG:
1267 xdp->prog_id = tun_xdp_query(dev);
1268 xdp->prog_attached = !!xdp->prog_id;
1269 return 0;
1270 default:
1271 return -EINVAL;
1272 }
1273 }
1274
1275 static const struct net_device_ops tun_netdev_ops = {
1276 .ndo_uninit = tun_net_uninit,
1277 .ndo_open = tun_net_open,
1278 .ndo_stop = tun_net_close,
1279 .ndo_start_xmit = tun_net_xmit,
1280 .ndo_fix_features = tun_net_fix_features,
1281 .ndo_select_queue = tun_select_queue,
1282 #ifdef CONFIG_NET_POLL_CONTROLLER
1283 .ndo_poll_controller = tun_poll_controller,
1284 #endif
1285 .ndo_set_rx_headroom = tun_set_headroom,
1286 .ndo_get_stats64 = tun_net_get_stats64,
1287 };
1288
1289 static int tun_xdp_xmit(struct net_device *dev, struct xdp_buff *xdp)
1290 {
1291 struct tun_struct *tun = netdev_priv(dev);
1292 struct xdp_buff *buff = xdp->data_hard_start;
1293 int headroom = xdp->data - xdp->data_hard_start;
1294 struct tun_file *tfile;
1295 u32 numqueues;
1296 int ret = 0;
1297
1298 /* Assure headroom is available and buff is properly aligned */
1299 if (unlikely(headroom < sizeof(*xdp) || tun_is_xdp_buff(xdp)))
1300 return -ENOSPC;
1301
1302 *buff = *xdp;
1303
1304 rcu_read_lock();
1305
1306 numqueues = READ_ONCE(tun->numqueues);
1307 if (!numqueues) {
1308 ret = -ENOSPC;
1309 goto out;
1310 }
1311
1312 tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
1313 numqueues]);
1314 /* Encode the XDP flag into lowest bit for consumer to differ
1315 * XDP buffer from sk_buff.
1316 */
1317 if (ptr_ring_produce(&tfile->tx_ring, tun_xdp_to_ptr(buff))) {
1318 this_cpu_inc(tun->pcpu_stats->tx_dropped);
1319 ret = -ENOSPC;
1320 }
1321
1322 out:
1323 rcu_read_unlock();
1324 return ret;
1325 }
1326
1327 static void tun_xdp_flush(struct net_device *dev)
1328 {
1329 struct tun_struct *tun = netdev_priv(dev);
1330 struct tun_file *tfile;
1331 u32 numqueues;
1332
1333 rcu_read_lock();
1334
1335 numqueues = READ_ONCE(tun->numqueues);
1336 if (!numqueues)
1337 goto out;
1338
1339 tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
1340 numqueues]);
1341 /* Notify and wake up reader process */
1342 if (tfile->flags & TUN_FASYNC)
1343 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1344 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1345
1346 out:
1347 rcu_read_unlock();
1348 }
1349
1350 static const struct net_device_ops tap_netdev_ops = {
1351 .ndo_uninit = tun_net_uninit,
1352 .ndo_open = tun_net_open,
1353 .ndo_stop = tun_net_close,
1354 .ndo_start_xmit = tun_net_xmit,
1355 .ndo_fix_features = tun_net_fix_features,
1356 .ndo_set_rx_mode = tun_net_mclist,
1357 .ndo_set_mac_address = eth_mac_addr,
1358 .ndo_validate_addr = eth_validate_addr,
1359 .ndo_select_queue = tun_select_queue,
1360 #ifdef CONFIG_NET_POLL_CONTROLLER
1361 .ndo_poll_controller = tun_poll_controller,
1362 #endif
1363 .ndo_features_check = passthru_features_check,
1364 .ndo_set_rx_headroom = tun_set_headroom,
1365 .ndo_get_stats64 = tun_net_get_stats64,
1366 .ndo_bpf = tun_xdp,
1367 .ndo_xdp_xmit = tun_xdp_xmit,
1368 .ndo_xdp_flush = tun_xdp_flush,
1369 };
1370
1371 static void tun_flow_init(struct tun_struct *tun)
1372 {
1373 int i;
1374
1375 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1376 INIT_HLIST_HEAD(&tun->flows[i]);
1377
1378 tun->ageing_time = TUN_FLOW_EXPIRE;
1379 timer_setup(&tun->flow_gc_timer, tun_flow_cleanup, 0);
1380 mod_timer(&tun->flow_gc_timer,
1381 round_jiffies_up(jiffies + tun->ageing_time));
1382 }
1383
1384 static void tun_flow_uninit(struct tun_struct *tun)
1385 {
1386 del_timer_sync(&tun->flow_gc_timer);
1387 tun_flow_flush(tun);
1388 }
1389
1390 #define MIN_MTU 68
1391 #define MAX_MTU 65535
1392
1393 /* Initialize net device. */
1394 static void tun_net_init(struct net_device *dev)
1395 {
1396 struct tun_struct *tun = netdev_priv(dev);
1397
1398 switch (tun->flags & TUN_TYPE_MASK) {
1399 case IFF_TUN:
1400 dev->netdev_ops = &tun_netdev_ops;
1401
1402 /* Point-to-Point TUN Device */
1403 dev->hard_header_len = 0;
1404 dev->addr_len = 0;
1405 dev->mtu = 1500;
1406
1407 /* Zero header length */
1408 dev->type = ARPHRD_NONE;
1409 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1410 break;
1411
1412 case IFF_TAP:
1413 dev->netdev_ops = &tap_netdev_ops;
1414 /* Ethernet TAP Device */
1415 ether_setup(dev);
1416 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1417 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1418
1419 eth_hw_addr_random(dev);
1420
1421 break;
1422 }
1423
1424 dev->min_mtu = MIN_MTU;
1425 dev->max_mtu = MAX_MTU - dev->hard_header_len;
1426 }
1427
1428 /* Character device part */
1429
1430 /* Poll */
1431 static __poll_t tun_chr_poll(struct file *file, poll_table *wait)
1432 {
1433 struct tun_file *tfile = file->private_data;
1434 struct tun_struct *tun = tun_get(tfile);
1435 struct sock *sk;
1436 __poll_t mask = 0;
1437
1438 if (!tun)
1439 return EPOLLERR;
1440
1441 sk = tfile->socket.sk;
1442
1443 tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
1444
1445 poll_wait(file, sk_sleep(sk), wait);
1446
1447 if (!ptr_ring_empty(&tfile->tx_ring))
1448 mask |= EPOLLIN | EPOLLRDNORM;
1449
1450 if (tun->dev->flags & IFF_UP &&
1451 (sock_writeable(sk) ||
1452 (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1453 sock_writeable(sk))))
1454 mask |= EPOLLOUT | EPOLLWRNORM;
1455
1456 if (tun->dev->reg_state != NETREG_REGISTERED)
1457 mask = EPOLLERR;
1458
1459 tun_put(tun);
1460 return mask;
1461 }
1462
1463 static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile,
1464 size_t len,
1465 const struct iov_iter *it)
1466 {
1467 struct sk_buff *skb;
1468 size_t linear;
1469 int err;
1470 int i;
1471
1472 if (it->nr_segs > MAX_SKB_FRAGS + 1)
1473 return ERR_PTR(-ENOMEM);
1474
1475 local_bh_disable();
1476 skb = napi_get_frags(&tfile->napi);
1477 local_bh_enable();
1478 if (!skb)
1479 return ERR_PTR(-ENOMEM);
1480
1481 linear = iov_iter_single_seg_count(it);
1482 err = __skb_grow(skb, linear);
1483 if (err)
1484 goto free;
1485
1486 skb->len = len;
1487 skb->data_len = len - linear;
1488 skb->truesize += skb->data_len;
1489
1490 for (i = 1; i < it->nr_segs; i++) {
1491 struct page_frag *pfrag = &current->task_frag;
1492 size_t fragsz = it->iov[i].iov_len;
1493
1494 if (fragsz == 0 || fragsz > PAGE_SIZE) {
1495 err = -EINVAL;
1496 goto free;
1497 }
1498
1499 if (!skb_page_frag_refill(fragsz, pfrag, GFP_KERNEL)) {
1500 err = -ENOMEM;
1501 goto free;
1502 }
1503
1504 skb_fill_page_desc(skb, i - 1, pfrag->page,
1505 pfrag->offset, fragsz);
1506 page_ref_inc(pfrag->page);
1507 pfrag->offset += fragsz;
1508 }
1509
1510 return skb;
1511 free:
1512 /* frees skb and all frags allocated with napi_alloc_frag() */
1513 napi_free_frags(&tfile->napi);
1514 return ERR_PTR(err);
1515 }
1516
1517 /* prepad is the amount to reserve at front. len is length after that.
1518 * linear is a hint as to how much to copy (usually headers). */
1519 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1520 size_t prepad, size_t len,
1521 size_t linear, int noblock)
1522 {
1523 struct sock *sk = tfile->socket.sk;
1524 struct sk_buff *skb;
1525 int err;
1526
1527 /* Under a page? Don't bother with paged skb. */
1528 if (prepad + len < PAGE_SIZE || !linear)
1529 linear = len;
1530
1531 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1532 &err, 0);
1533 if (!skb)
1534 return ERR_PTR(err);
1535
1536 skb_reserve(skb, prepad);
1537 skb_put(skb, linear);
1538 skb->data_len = len - linear;
1539 skb->len += len - linear;
1540
1541 return skb;
1542 }
1543
1544 static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile,
1545 struct sk_buff *skb, int more)
1546 {
1547 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1548 struct sk_buff_head process_queue;
1549 u32 rx_batched = tun->rx_batched;
1550 bool rcv = false;
1551
1552 if (!rx_batched || (!more && skb_queue_empty(queue))) {
1553 local_bh_disable();
1554 netif_receive_skb(skb);
1555 local_bh_enable();
1556 return;
1557 }
1558
1559 spin_lock(&queue->lock);
1560 if (!more || skb_queue_len(queue) == rx_batched) {
1561 __skb_queue_head_init(&process_queue);
1562 skb_queue_splice_tail_init(queue, &process_queue);
1563 rcv = true;
1564 } else {
1565 __skb_queue_tail(queue, skb);
1566 }
1567 spin_unlock(&queue->lock);
1568
1569 if (rcv) {
1570 struct sk_buff *nskb;
1571
1572 local_bh_disable();
1573 while ((nskb = __skb_dequeue(&process_queue)))
1574 netif_receive_skb(nskb);
1575 netif_receive_skb(skb);
1576 local_bh_enable();
1577 }
1578 }
1579
1580 static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile,
1581 int len, int noblock, bool zerocopy)
1582 {
1583 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
1584 return false;
1585
1586 if (tfile->socket.sk->sk_sndbuf != INT_MAX)
1587 return false;
1588
1589 if (!noblock)
1590 return false;
1591
1592 if (zerocopy)
1593 return false;
1594
1595 if (SKB_DATA_ALIGN(len + TUN_RX_PAD) +
1596 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
1597 return false;
1598
1599 return true;
1600 }
1601
1602 static struct sk_buff *tun_build_skb(struct tun_struct *tun,
1603 struct tun_file *tfile,
1604 struct iov_iter *from,
1605 struct virtio_net_hdr *hdr,
1606 int len, int *skb_xdp)
1607 {
1608 struct page_frag *alloc_frag = &current->task_frag;
1609 struct sk_buff *skb;
1610 struct bpf_prog *xdp_prog;
1611 int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1612 unsigned int delta = 0;
1613 char *buf;
1614 size_t copied;
1615 bool xdp_xmit = false;
1616 int err, pad = TUN_RX_PAD;
1617
1618 rcu_read_lock();
1619 xdp_prog = rcu_dereference(tun->xdp_prog);
1620 if (xdp_prog)
1621 pad += TUN_HEADROOM;
1622 buflen += SKB_DATA_ALIGN(len + pad);
1623 rcu_read_unlock();
1624
1625 alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES);
1626 if (unlikely(!skb_page_frag_refill(buflen, alloc_frag, GFP_KERNEL)))
1627 return ERR_PTR(-ENOMEM);
1628
1629 buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
1630 copied = copy_page_from_iter(alloc_frag->page,
1631 alloc_frag->offset + pad,
1632 len, from);
1633 if (copied != len)
1634 return ERR_PTR(-EFAULT);
1635
1636 /* There's a small window that XDP may be set after the check
1637 * of xdp_prog above, this should be rare and for simplicity
1638 * we do XDP on skb in case the headroom is not enough.
1639 */
1640 if (hdr->gso_type || !xdp_prog)
1641 *skb_xdp = 1;
1642 else
1643 *skb_xdp = 0;
1644
1645 preempt_disable();
1646 rcu_read_lock();
1647 xdp_prog = rcu_dereference(tun->xdp_prog);
1648 if (xdp_prog && !*skb_xdp) {
1649 struct xdp_buff xdp;
1650 void *orig_data;
1651 u32 act;
1652
1653 xdp.data_hard_start = buf;
1654 xdp.data = buf + pad;
1655 xdp_set_data_meta_invalid(&xdp);
1656 xdp.data_end = xdp.data + len;
1657 xdp.rxq = &tfile->xdp_rxq;
1658 orig_data = xdp.data;
1659 act = bpf_prog_run_xdp(xdp_prog, &xdp);
1660
1661 switch (act) {
1662 case XDP_REDIRECT:
1663 get_page(alloc_frag->page);
1664 alloc_frag->offset += buflen;
1665 err = xdp_do_redirect(tun->dev, &xdp, xdp_prog);
1666 xdp_do_flush_map();
1667 if (err)
1668 goto err_redirect;
1669 rcu_read_unlock();
1670 preempt_enable();
1671 return NULL;
1672 case XDP_TX:
1673 xdp_xmit = true;
1674 /* fall through */
1675 case XDP_PASS:
1676 delta = orig_data - xdp.data;
1677 break;
1678 default:
1679 bpf_warn_invalid_xdp_action(act);
1680 /* fall through */
1681 case XDP_ABORTED:
1682 trace_xdp_exception(tun->dev, xdp_prog, act);
1683 /* fall through */
1684 case XDP_DROP:
1685 goto err_xdp;
1686 }
1687 }
1688
1689 skb = build_skb(buf, buflen);
1690 if (!skb) {
1691 rcu_read_unlock();
1692 preempt_enable();
1693 return ERR_PTR(-ENOMEM);
1694 }
1695
1696 skb_reserve(skb, pad - delta);
1697 skb_put(skb, len + delta);
1698 get_page(alloc_frag->page);
1699 alloc_frag->offset += buflen;
1700
1701 if (xdp_xmit) {
1702 skb->dev = tun->dev;
1703 generic_xdp_tx(skb, xdp_prog);
1704 rcu_read_unlock();
1705 preempt_enable();
1706 return NULL;
1707 }
1708
1709 rcu_read_unlock();
1710 preempt_enable();
1711
1712 return skb;
1713
1714 err_redirect:
1715 put_page(alloc_frag->page);
1716 err_xdp:
1717 rcu_read_unlock();
1718 preempt_enable();
1719 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1720 return NULL;
1721 }
1722
1723 /* Get packet from user space buffer */
1724 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1725 void *msg_control, struct iov_iter *from,
1726 int noblock, bool more)
1727 {
1728 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1729 struct sk_buff *skb;
1730 size_t total_len = iov_iter_count(from);
1731 size_t len = total_len, align = tun->align, linear;
1732 struct virtio_net_hdr gso = { 0 };
1733 struct tun_pcpu_stats *stats;
1734 int good_linear;
1735 int copylen;
1736 bool zerocopy = false;
1737 int err;
1738 u32 rxhash = 0;
1739 int skb_xdp = 1;
1740 bool frags = tun_napi_frags_enabled(tun);
1741
1742 if (!(tun->dev->flags & IFF_UP))
1743 return -EIO;
1744
1745 if (!(tun->flags & IFF_NO_PI)) {
1746 if (len < sizeof(pi))
1747 return -EINVAL;
1748 len -= sizeof(pi);
1749
1750 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1751 return -EFAULT;
1752 }
1753
1754 if (tun->flags & IFF_VNET_HDR) {
1755 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1756
1757 if (len < vnet_hdr_sz)
1758 return -EINVAL;
1759 len -= vnet_hdr_sz;
1760
1761 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1762 return -EFAULT;
1763
1764 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1765 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1766 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1767
1768 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1769 return -EINVAL;
1770 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1771 }
1772
1773 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1774 align += NET_IP_ALIGN;
1775 if (unlikely(len < ETH_HLEN ||
1776 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1777 return -EINVAL;
1778 }
1779
1780 good_linear = SKB_MAX_HEAD(align);
1781
1782 if (msg_control) {
1783 struct iov_iter i = *from;
1784
1785 /* There are 256 bytes to be copied in skb, so there is
1786 * enough room for skb expand head in case it is used.
1787 * The rest of the buffer is mapped from userspace.
1788 */
1789 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1790 if (copylen > good_linear)
1791 copylen = good_linear;
1792 linear = copylen;
1793 iov_iter_advance(&i, copylen);
1794 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1795 zerocopy = true;
1796 }
1797
1798 if (!frags && tun_can_build_skb(tun, tfile, len, noblock, zerocopy)) {
1799 /* For the packet that is not easy to be processed
1800 * (e.g gso or jumbo packet), we will do it at after
1801 * skb was created with generic XDP routine.
1802 */
1803 skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp);
1804 if (IS_ERR(skb)) {
1805 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1806 return PTR_ERR(skb);
1807 }
1808 if (!skb)
1809 return total_len;
1810 } else {
1811 if (!zerocopy) {
1812 copylen = len;
1813 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1814 linear = good_linear;
1815 else
1816 linear = tun16_to_cpu(tun, gso.hdr_len);
1817 }
1818
1819 if (frags) {
1820 mutex_lock(&tfile->napi_mutex);
1821 skb = tun_napi_alloc_frags(tfile, copylen, from);
1822 /* tun_napi_alloc_frags() enforces a layout for the skb.
1823 * If zerocopy is enabled, then this layout will be
1824 * overwritten by zerocopy_sg_from_iter().
1825 */
1826 zerocopy = false;
1827 } else {
1828 skb = tun_alloc_skb(tfile, align, copylen, linear,
1829 noblock);
1830 }
1831
1832 if (IS_ERR(skb)) {
1833 if (PTR_ERR(skb) != -EAGAIN)
1834 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1835 if (frags)
1836 mutex_unlock(&tfile->napi_mutex);
1837 return PTR_ERR(skb);
1838 }
1839
1840 if (zerocopy)
1841 err = zerocopy_sg_from_iter(skb, from);
1842 else
1843 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1844
1845 if (err) {
1846 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1847 kfree_skb(skb);
1848 if (frags) {
1849 tfile->napi.skb = NULL;
1850 mutex_unlock(&tfile->napi_mutex);
1851 }
1852
1853 return -EFAULT;
1854 }
1855 }
1856
1857 if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1858 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
1859 kfree_skb(skb);
1860 if (frags) {
1861 tfile->napi.skb = NULL;
1862 mutex_unlock(&tfile->napi_mutex);
1863 }
1864
1865 return -EINVAL;
1866 }
1867
1868 switch (tun->flags & TUN_TYPE_MASK) {
1869 case IFF_TUN:
1870 if (tun->flags & IFF_NO_PI) {
1871 u8 ip_version = skb->len ? (skb->data[0] >> 4) : 0;
1872
1873 switch (ip_version) {
1874 case 4:
1875 pi.proto = htons(ETH_P_IP);
1876 break;
1877 case 6:
1878 pi.proto = htons(ETH_P_IPV6);
1879 break;
1880 default:
1881 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1882 kfree_skb(skb);
1883 return -EINVAL;
1884 }
1885 }
1886
1887 skb_reset_mac_header(skb);
1888 skb->protocol = pi.proto;
1889 skb->dev = tun->dev;
1890 break;
1891 case IFF_TAP:
1892 if (!frags)
1893 skb->protocol = eth_type_trans(skb, tun->dev);
1894 break;
1895 }
1896
1897 /* copy skb_ubuf_info for callback when skb has no error */
1898 if (zerocopy) {
1899 skb_shinfo(skb)->destructor_arg = msg_control;
1900 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1901 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1902 } else if (msg_control) {
1903 struct ubuf_info *uarg = msg_control;
1904 uarg->callback(uarg, false);
1905 }
1906
1907 skb_reset_network_header(skb);
1908 skb_probe_transport_header(skb, 0);
1909
1910 if (skb_xdp) {
1911 struct bpf_prog *xdp_prog;
1912 int ret;
1913
1914 rcu_read_lock();
1915 xdp_prog = rcu_dereference(tun->xdp_prog);
1916 if (xdp_prog) {
1917 ret = do_xdp_generic(xdp_prog, skb);
1918 if (ret != XDP_PASS) {
1919 rcu_read_unlock();
1920 return total_len;
1921 }
1922 }
1923 rcu_read_unlock();
1924 }
1925
1926 rcu_read_lock();
1927 if (!rcu_dereference(tun->steering_prog))
1928 rxhash = __skb_get_hash_symmetric(skb);
1929 rcu_read_unlock();
1930
1931 if (frags) {
1932 /* Exercise flow dissector code path. */
1933 u32 headlen = eth_get_headlen(skb->data, 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 mutex_unlock(&tfile->napi_mutex);
1939 WARN_ON(1);
1940 return -ENOMEM;
1941 }
1942
1943 local_bh_disable();
1944 napi_gro_frags(&tfile->napi);
1945 local_bh_enable();
1946 mutex_unlock(&tfile->napi_mutex);
1947 } else if (tfile->napi_enabled) {
1948 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1949 int queue_len;
1950
1951 spin_lock_bh(&queue->lock);
1952 __skb_queue_tail(queue, skb);
1953 queue_len = skb_queue_len(queue);
1954 spin_unlock(&queue->lock);
1955
1956 if (!more || queue_len > NAPI_POLL_WEIGHT)
1957 napi_schedule(&tfile->napi);
1958
1959 local_bh_enable();
1960 } else if (!IS_ENABLED(CONFIG_4KSTACKS)) {
1961 tun_rx_batched(tun, tfile, skb, more);
1962 } else {
1963 netif_rx_ni(skb);
1964 }
1965
1966 stats = get_cpu_ptr(tun->pcpu_stats);
1967 u64_stats_update_begin(&stats->syncp);
1968 stats->rx_packets++;
1969 stats->rx_bytes += len;
1970 u64_stats_update_end(&stats->syncp);
1971 put_cpu_ptr(stats);
1972
1973 if (rxhash)
1974 tun_flow_update(tun, rxhash, tfile);
1975
1976 return total_len;
1977 }
1978
1979 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
1980 {
1981 struct file *file = iocb->ki_filp;
1982 struct tun_file *tfile = file->private_data;
1983 struct tun_struct *tun = tun_get(tfile);
1984 ssize_t result;
1985
1986 if (!tun)
1987 return -EBADFD;
1988
1989 result = tun_get_user(tun, tfile, NULL, from,
1990 file->f_flags & O_NONBLOCK, false);
1991
1992 tun_put(tun);
1993 return result;
1994 }
1995
1996 static ssize_t tun_put_user_xdp(struct tun_struct *tun,
1997 struct tun_file *tfile,
1998 struct xdp_buff *xdp,
1999 struct iov_iter *iter)
2000 {
2001 int vnet_hdr_sz = 0;
2002 size_t size = xdp->data_end - xdp->data;
2003 struct tun_pcpu_stats *stats;
2004 size_t ret;
2005
2006 if (tun->flags & IFF_VNET_HDR) {
2007 struct virtio_net_hdr gso = { 0 };
2008
2009 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2010 if (unlikely(iov_iter_count(iter) < vnet_hdr_sz))
2011 return -EINVAL;
2012 if (unlikely(copy_to_iter(&gso, sizeof(gso), iter) !=
2013 sizeof(gso)))
2014 return -EFAULT;
2015 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2016 }
2017
2018 ret = copy_to_iter(xdp->data, size, iter) + vnet_hdr_sz;
2019
2020 stats = get_cpu_ptr(tun->pcpu_stats);
2021 u64_stats_update_begin(&stats->syncp);
2022 stats->tx_packets++;
2023 stats->tx_bytes += ret;
2024 u64_stats_update_end(&stats->syncp);
2025 put_cpu_ptr(tun->pcpu_stats);
2026
2027 return ret;
2028 }
2029
2030 /* Put packet to the user space buffer */
2031 static ssize_t tun_put_user(struct tun_struct *tun,
2032 struct tun_file *tfile,
2033 struct sk_buff *skb,
2034 struct iov_iter *iter)
2035 {
2036 struct tun_pi pi = { 0, skb->protocol };
2037 struct tun_pcpu_stats *stats;
2038 ssize_t total;
2039 int vlan_offset = 0;
2040 int vlan_hlen = 0;
2041 int vnet_hdr_sz = 0;
2042
2043 if (skb_vlan_tag_present(skb))
2044 vlan_hlen = VLAN_HLEN;
2045
2046 if (tun->flags & IFF_VNET_HDR)
2047 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2048
2049 total = skb->len + vlan_hlen + vnet_hdr_sz;
2050
2051 if (!(tun->flags & IFF_NO_PI)) {
2052 if (iov_iter_count(iter) < sizeof(pi))
2053 return -EINVAL;
2054
2055 total += sizeof(pi);
2056 if (iov_iter_count(iter) < total) {
2057 /* Packet will be striped */
2058 pi.flags |= TUN_PKT_STRIP;
2059 }
2060
2061 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
2062 return -EFAULT;
2063 }
2064
2065 if (vnet_hdr_sz) {
2066 struct virtio_net_hdr gso;
2067
2068 if (iov_iter_count(iter) < vnet_hdr_sz)
2069 return -EINVAL;
2070
2071 if (virtio_net_hdr_from_skb(skb, &gso,
2072 tun_is_little_endian(tun), true)) {
2073 struct skb_shared_info *sinfo = skb_shinfo(skb);
2074 pr_err("unexpected GSO type: "
2075 "0x%x, gso_size %d, hdr_len %d\n",
2076 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
2077 tun16_to_cpu(tun, gso.hdr_len));
2078 print_hex_dump(KERN_ERR, "tun: ",
2079 DUMP_PREFIX_NONE,
2080 16, 1, skb->head,
2081 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
2082 WARN_ON_ONCE(1);
2083 return -EINVAL;
2084 }
2085
2086 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
2087 return -EFAULT;
2088
2089 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2090 }
2091
2092 if (vlan_hlen) {
2093 int ret;
2094 struct veth veth;
2095
2096 veth.h_vlan_proto = skb->vlan_proto;
2097 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
2098
2099 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
2100
2101 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
2102 if (ret || !iov_iter_count(iter))
2103 goto done;
2104
2105 ret = copy_to_iter(&veth, sizeof(veth), iter);
2106 if (ret != sizeof(veth) || !iov_iter_count(iter))
2107 goto done;
2108 }
2109
2110 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
2111
2112 done:
2113 /* caller is in process context, */
2114 stats = get_cpu_ptr(tun->pcpu_stats);
2115 u64_stats_update_begin(&stats->syncp);
2116 stats->tx_packets++;
2117 stats->tx_bytes += skb->len + vlan_hlen;
2118 u64_stats_update_end(&stats->syncp);
2119 put_cpu_ptr(tun->pcpu_stats);
2120
2121 return total;
2122 }
2123
2124 static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err)
2125 {
2126 DECLARE_WAITQUEUE(wait, current);
2127 void *ptr = NULL;
2128 int error = 0;
2129
2130 ptr = ptr_ring_consume(&tfile->tx_ring);
2131 if (ptr)
2132 goto out;
2133 if (noblock) {
2134 error = -EAGAIN;
2135 goto out;
2136 }
2137
2138 add_wait_queue(&tfile->wq.wait, &wait);
2139 current->state = TASK_INTERRUPTIBLE;
2140
2141 while (1) {
2142 ptr = ptr_ring_consume(&tfile->tx_ring);
2143 if (ptr)
2144 break;
2145 if (signal_pending(current)) {
2146 error = -ERESTARTSYS;
2147 break;
2148 }
2149 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
2150 error = -EFAULT;
2151 break;
2152 }
2153
2154 schedule();
2155 }
2156
2157 current->state = TASK_RUNNING;
2158 remove_wait_queue(&tfile->wq.wait, &wait);
2159
2160 out:
2161 *err = error;
2162 return ptr;
2163 }
2164
2165 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
2166 struct iov_iter *to,
2167 int noblock, void *ptr)
2168 {
2169 ssize_t ret;
2170 int err;
2171
2172 tun_debug(KERN_INFO, tun, "tun_do_read\n");
2173
2174 if (!iov_iter_count(to)) {
2175 tun_ptr_free(ptr);
2176 return 0;
2177 }
2178
2179 if (!ptr) {
2180 /* Read frames from ring */
2181 ptr = tun_ring_recv(tfile, noblock, &err);
2182 if (!ptr)
2183 return err;
2184 }
2185
2186 if (tun_is_xdp_buff(ptr)) {
2187 struct xdp_buff *xdp = tun_ptr_to_xdp(ptr);
2188
2189 ret = tun_put_user_xdp(tun, tfile, xdp, to);
2190 put_page(virt_to_head_page(xdp->data));
2191 } else {
2192 struct sk_buff *skb = ptr;
2193
2194 ret = tun_put_user(tun, tfile, skb, to);
2195 if (unlikely(ret < 0))
2196 kfree_skb(skb);
2197 else
2198 consume_skb(skb);
2199 }
2200
2201 return ret;
2202 }
2203
2204 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
2205 {
2206 struct file *file = iocb->ki_filp;
2207 struct tun_file *tfile = file->private_data;
2208 struct tun_struct *tun = tun_get(tfile);
2209 ssize_t len = iov_iter_count(to), ret;
2210
2211 if (!tun)
2212 return -EBADFD;
2213 ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK, NULL);
2214 ret = min_t(ssize_t, ret, len);
2215 if (ret > 0)
2216 iocb->ki_pos = ret;
2217 tun_put(tun);
2218 return ret;
2219 }
2220
2221 static void tun_prog_free(struct rcu_head *rcu)
2222 {
2223 struct tun_prog *prog = container_of(rcu, struct tun_prog, rcu);
2224
2225 bpf_prog_destroy(prog->prog);
2226 kfree(prog);
2227 }
2228
2229 static int __tun_set_ebpf(struct tun_struct *tun,
2230 struct tun_prog __rcu **prog_p,
2231 struct bpf_prog *prog)
2232 {
2233 struct tun_prog *old, *new = NULL;
2234
2235 if (prog) {
2236 new = kmalloc(sizeof(*new), GFP_KERNEL);
2237 if (!new)
2238 return -ENOMEM;
2239 new->prog = prog;
2240 }
2241
2242 spin_lock_bh(&tun->lock);
2243 old = rcu_dereference_protected(*prog_p,
2244 lockdep_is_held(&tun->lock));
2245 rcu_assign_pointer(*prog_p, new);
2246 spin_unlock_bh(&tun->lock);
2247
2248 if (old)
2249 call_rcu(&old->rcu, tun_prog_free);
2250
2251 return 0;
2252 }
2253
2254 static void tun_free_netdev(struct net_device *dev)
2255 {
2256 struct tun_struct *tun = netdev_priv(dev);
2257
2258 BUG_ON(!(list_empty(&tun->disabled)));
2259 free_percpu(tun->pcpu_stats);
2260 tun_flow_uninit(tun);
2261 security_tun_dev_free_security(tun->security);
2262 __tun_set_ebpf(tun, &tun->steering_prog, NULL);
2263 __tun_set_ebpf(tun, &tun->filter_prog, NULL);
2264 }
2265
2266 static void tun_setup(struct net_device *dev)
2267 {
2268 struct tun_struct *tun = netdev_priv(dev);
2269
2270 tun->owner = INVALID_UID;
2271 tun->group = INVALID_GID;
2272
2273 dev->ethtool_ops = &tun_ethtool_ops;
2274 dev->needs_free_netdev = true;
2275 dev->priv_destructor = tun_free_netdev;
2276 /* We prefer our own queue length */
2277 dev->tx_queue_len = TUN_READQ_SIZE;
2278 }
2279
2280 /* Trivial set of netlink ops to allow deleting tun or tap
2281 * device with netlink.
2282 */
2283 static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
2284 struct netlink_ext_ack *extack)
2285 {
2286 return -EINVAL;
2287 }
2288
2289 static struct rtnl_link_ops tun_link_ops __read_mostly = {
2290 .kind = DRV_NAME,
2291 .priv_size = sizeof(struct tun_struct),
2292 .setup = tun_setup,
2293 .validate = tun_validate,
2294 };
2295
2296 static void tun_sock_write_space(struct sock *sk)
2297 {
2298 struct tun_file *tfile;
2299 wait_queue_head_t *wqueue;
2300
2301 if (!sock_writeable(sk))
2302 return;
2303
2304 if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
2305 return;
2306
2307 wqueue = sk_sleep(sk);
2308 if (wqueue && waitqueue_active(wqueue))
2309 wake_up_interruptible_sync_poll(wqueue, EPOLLOUT |
2310 EPOLLWRNORM | EPOLLWRBAND);
2311
2312 tfile = container_of(sk, struct tun_file, sk);
2313 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
2314 }
2315
2316 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
2317 {
2318 int ret;
2319 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2320 struct tun_struct *tun = tun_get(tfile);
2321
2322 if (!tun)
2323 return -EBADFD;
2324
2325 ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter,
2326 m->msg_flags & MSG_DONTWAIT,
2327 m->msg_flags & MSG_MORE);
2328 tun_put(tun);
2329 return ret;
2330 }
2331
2332 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
2333 int flags)
2334 {
2335 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2336 struct tun_struct *tun = tun_get(tfile);
2337 void *ptr = m->msg_control;
2338 int ret;
2339
2340 if (!tun) {
2341 ret = -EBADFD;
2342 goto out_free;
2343 }
2344
2345 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
2346 ret = -EINVAL;
2347 goto out_put_tun;
2348 }
2349 if (flags & MSG_ERRQUEUE) {
2350 ret = sock_recv_errqueue(sock->sk, m, total_len,
2351 SOL_PACKET, TUN_TX_TIMESTAMP);
2352 goto out;
2353 }
2354 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT, ptr);
2355 if (ret > (ssize_t)total_len) {
2356 m->msg_flags |= MSG_TRUNC;
2357 ret = flags & MSG_TRUNC ? ret : total_len;
2358 }
2359 out:
2360 tun_put(tun);
2361 return ret;
2362
2363 out_put_tun:
2364 tun_put(tun);
2365 out_free:
2366 tun_ptr_free(ptr);
2367 return ret;
2368 }
2369
2370 static int tun_ptr_peek_len(void *ptr)
2371 {
2372 if (likely(ptr)) {
2373 if (tun_is_xdp_buff(ptr)) {
2374 struct xdp_buff *xdp = tun_ptr_to_xdp(ptr);
2375
2376 return xdp->data_end - xdp->data;
2377 }
2378 return __skb_array_len_with_tag(ptr);
2379 } else {
2380 return 0;
2381 }
2382 }
2383
2384 static int tun_peek_len(struct socket *sock)
2385 {
2386 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2387 struct tun_struct *tun;
2388 int ret = 0;
2389
2390 tun = tun_get(tfile);
2391 if (!tun)
2392 return 0;
2393
2394 ret = PTR_RING_PEEK_CALL(&tfile->tx_ring, tun_ptr_peek_len);
2395 tun_put(tun);
2396
2397 return ret;
2398 }
2399
2400 /* Ops structure to mimic raw sockets with tun */
2401 static const struct proto_ops tun_socket_ops = {
2402 .peek_len = tun_peek_len,
2403 .sendmsg = tun_sendmsg,
2404 .recvmsg = tun_recvmsg,
2405 };
2406
2407 static struct proto tun_proto = {
2408 .name = "tun",
2409 .owner = THIS_MODULE,
2410 .obj_size = sizeof(struct tun_file),
2411 };
2412
2413 static int tun_flags(struct tun_struct *tun)
2414 {
2415 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
2416 }
2417
2418 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
2419 char *buf)
2420 {
2421 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2422 return sprintf(buf, "0x%x\n", tun_flags(tun));
2423 }
2424
2425 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
2426 char *buf)
2427 {
2428 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2429 return uid_valid(tun->owner)?
2430 sprintf(buf, "%u\n",
2431 from_kuid_munged(current_user_ns(), tun->owner)):
2432 sprintf(buf, "-1\n");
2433 }
2434
2435 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
2436 char *buf)
2437 {
2438 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2439 return gid_valid(tun->group) ?
2440 sprintf(buf, "%u\n",
2441 from_kgid_munged(current_user_ns(), tun->group)):
2442 sprintf(buf, "-1\n");
2443 }
2444
2445 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
2446 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
2447 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
2448
2449 static struct attribute *tun_dev_attrs[] = {
2450 &dev_attr_tun_flags.attr,
2451 &dev_attr_owner.attr,
2452 &dev_attr_group.attr,
2453 NULL
2454 };
2455
2456 static const struct attribute_group tun_attr_group = {
2457 .attrs = tun_dev_attrs
2458 };
2459
2460 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
2461 {
2462 struct tun_struct *tun;
2463 struct tun_file *tfile = file->private_data;
2464 struct net_device *dev;
2465 int err;
2466
2467 if (tfile->detached)
2468 return -EINVAL;
2469
2470 if ((ifr->ifr_flags & IFF_NAPI_FRAGS)) {
2471 if (!capable(CAP_NET_ADMIN))
2472 return -EPERM;
2473
2474 if (!(ifr->ifr_flags & IFF_NAPI) ||
2475 (ifr->ifr_flags & TUN_TYPE_MASK) != IFF_TAP)
2476 return -EINVAL;
2477 }
2478
2479 dev = __dev_get_by_name(net, ifr->ifr_name);
2480 if (dev) {
2481 if (ifr->ifr_flags & IFF_TUN_EXCL)
2482 return -EBUSY;
2483 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
2484 tun = netdev_priv(dev);
2485 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
2486 tun = netdev_priv(dev);
2487 else
2488 return -EINVAL;
2489
2490 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
2491 !!(tun->flags & IFF_MULTI_QUEUE))
2492 return -EINVAL;
2493
2494 if (tun_not_capable(tun))
2495 return -EPERM;
2496 err = security_tun_dev_open(tun->security);
2497 if (err < 0)
2498 return err;
2499
2500 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER,
2501 ifr->ifr_flags & IFF_NAPI);
2502 if (err < 0)
2503 return err;
2504
2505 if (tun->flags & IFF_MULTI_QUEUE &&
2506 (tun->numqueues + tun->numdisabled > 1)) {
2507 /* One or more queue has already been attached, no need
2508 * to initialize the device again.
2509 */
2510 return 0;
2511 }
2512 }
2513 else {
2514 char *name;
2515 unsigned long flags = 0;
2516 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
2517 MAX_TAP_QUEUES : 1;
2518
2519 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2520 return -EPERM;
2521 err = security_tun_dev_create();
2522 if (err < 0)
2523 return err;
2524
2525 /* Set dev type */
2526 if (ifr->ifr_flags & IFF_TUN) {
2527 /* TUN device */
2528 flags |= IFF_TUN;
2529 name = "tun%d";
2530 } else if (ifr->ifr_flags & IFF_TAP) {
2531 /* TAP device */
2532 flags |= IFF_TAP;
2533 name = "tap%d";
2534 } else
2535 return -EINVAL;
2536
2537 if (*ifr->ifr_name)
2538 name = ifr->ifr_name;
2539
2540 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
2541 NET_NAME_UNKNOWN, tun_setup, queues,
2542 queues);
2543
2544 if (!dev)
2545 return -ENOMEM;
2546 err = dev_get_valid_name(net, dev, name);
2547 if (err < 0)
2548 goto err_free_dev;
2549
2550 dev_net_set(dev, net);
2551 dev->rtnl_link_ops = &tun_link_ops;
2552 dev->ifindex = tfile->ifindex;
2553 dev->sysfs_groups[0] = &tun_attr_group;
2554
2555 tun = netdev_priv(dev);
2556 tun->dev = dev;
2557 tun->flags = flags;
2558 tun->txflt.count = 0;
2559 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
2560
2561 tun->align = NET_SKB_PAD;
2562 tun->filter_attached = false;
2563 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
2564 tun->rx_batched = 0;
2565 RCU_INIT_POINTER(tun->steering_prog, NULL);
2566
2567 tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats);
2568 if (!tun->pcpu_stats) {
2569 err = -ENOMEM;
2570 goto err_free_dev;
2571 }
2572
2573 spin_lock_init(&tun->lock);
2574
2575 err = security_tun_dev_alloc_security(&tun->security);
2576 if (err < 0)
2577 goto err_free_stat;
2578
2579 tun_net_init(dev);
2580 tun_flow_init(tun);
2581
2582 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
2583 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
2584 NETIF_F_HW_VLAN_STAG_TX;
2585 dev->features = dev->hw_features | NETIF_F_LLTX;
2586 dev->vlan_features = dev->features &
2587 ~(NETIF_F_HW_VLAN_CTAG_TX |
2588 NETIF_F_HW_VLAN_STAG_TX);
2589
2590 INIT_LIST_HEAD(&tun->disabled);
2591 err = tun_attach(tun, file, false, ifr->ifr_flags & IFF_NAPI);
2592 if (err < 0)
2593 goto err_free_flow;
2594
2595 err = register_netdevice(tun->dev);
2596 if (err < 0)
2597 goto err_detach;
2598 }
2599
2600 netif_carrier_on(tun->dev);
2601
2602 tun_debug(KERN_INFO, tun, "tun_set_iff\n");
2603
2604 tun->flags = (tun->flags & ~TUN_FEATURES) |
2605 (ifr->ifr_flags & TUN_FEATURES);
2606
2607 /* Make sure persistent devices do not get stuck in
2608 * xoff state.
2609 */
2610 if (netif_running(tun->dev))
2611 netif_tx_wake_all_queues(tun->dev);
2612
2613 strcpy(ifr->ifr_name, tun->dev->name);
2614 return 0;
2615
2616 err_detach:
2617 tun_detach_all(dev);
2618 /* register_netdevice() already called tun_free_netdev() */
2619 goto err_free_dev;
2620
2621 err_free_flow:
2622 tun_flow_uninit(tun);
2623 security_tun_dev_free_security(tun->security);
2624 err_free_stat:
2625 free_percpu(tun->pcpu_stats);
2626 err_free_dev:
2627 free_netdev(dev);
2628 return err;
2629 }
2630
2631 static void tun_get_iff(struct net *net, struct tun_struct *tun,
2632 struct ifreq *ifr)
2633 {
2634 tun_debug(KERN_INFO, tun, "tun_get_iff\n");
2635
2636 strcpy(ifr->ifr_name, tun->dev->name);
2637
2638 ifr->ifr_flags = tun_flags(tun);
2639
2640 }
2641
2642 /* This is like a cut-down ethtool ops, except done via tun fd so no
2643 * privs required. */
2644 static int set_offload(struct tun_struct *tun, unsigned long arg)
2645 {
2646 netdev_features_t features = 0;
2647
2648 if (arg & TUN_F_CSUM) {
2649 features |= NETIF_F_HW_CSUM;
2650 arg &= ~TUN_F_CSUM;
2651
2652 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
2653 if (arg & TUN_F_TSO_ECN) {
2654 features |= NETIF_F_TSO_ECN;
2655 arg &= ~TUN_F_TSO_ECN;
2656 }
2657 if (arg & TUN_F_TSO4)
2658 features |= NETIF_F_TSO;
2659 if (arg & TUN_F_TSO6)
2660 features |= NETIF_F_TSO6;
2661 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
2662 }
2663
2664 arg &= ~TUN_F_UFO;
2665 }
2666
2667 /* This gives the user a way to test for new features in future by
2668 * trying to set them. */
2669 if (arg)
2670 return -EINVAL;
2671
2672 tun->set_features = features;
2673 tun->dev->wanted_features &= ~TUN_USER_FEATURES;
2674 tun->dev->wanted_features |= features;
2675 netdev_update_features(tun->dev);
2676
2677 return 0;
2678 }
2679
2680 static void tun_detach_filter(struct tun_struct *tun, int n)
2681 {
2682 int i;
2683 struct tun_file *tfile;
2684
2685 for (i = 0; i < n; i++) {
2686 tfile = rtnl_dereference(tun->tfiles[i]);
2687 lock_sock(tfile->socket.sk);
2688 sk_detach_filter(tfile->socket.sk);
2689 release_sock(tfile->socket.sk);
2690 }
2691
2692 tun->filter_attached = false;
2693 }
2694
2695 static int tun_attach_filter(struct tun_struct *tun)
2696 {
2697 int i, ret = 0;
2698 struct tun_file *tfile;
2699
2700 for (i = 0; i < tun->numqueues; i++) {
2701 tfile = rtnl_dereference(tun->tfiles[i]);
2702 lock_sock(tfile->socket.sk);
2703 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
2704 release_sock(tfile->socket.sk);
2705 if (ret) {
2706 tun_detach_filter(tun, i);
2707 return ret;
2708 }
2709 }
2710
2711 tun->filter_attached = true;
2712 return ret;
2713 }
2714
2715 static void tun_set_sndbuf(struct tun_struct *tun)
2716 {
2717 struct tun_file *tfile;
2718 int i;
2719
2720 for (i = 0; i < tun->numqueues; i++) {
2721 tfile = rtnl_dereference(tun->tfiles[i]);
2722 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
2723 }
2724 }
2725
2726 static int tun_set_queue(struct file *file, struct ifreq *ifr)
2727 {
2728 struct tun_file *tfile = file->private_data;
2729 struct tun_struct *tun;
2730 int ret = 0;
2731
2732 rtnl_lock();
2733
2734 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
2735 tun = tfile->detached;
2736 if (!tun) {
2737 ret = -EINVAL;
2738 goto unlock;
2739 }
2740 ret = security_tun_dev_attach_queue(tun->security);
2741 if (ret < 0)
2742 goto unlock;
2743 ret = tun_attach(tun, file, false, tun->flags & IFF_NAPI);
2744 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
2745 tun = rtnl_dereference(tfile->tun);
2746 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
2747 ret = -EINVAL;
2748 else
2749 __tun_detach(tfile, false);
2750 } else
2751 ret = -EINVAL;
2752
2753 unlock:
2754 rtnl_unlock();
2755 return ret;
2756 }
2757
2758 static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog **prog_p,
2759 void __user *data)
2760 {
2761 struct bpf_prog *prog;
2762 int fd;
2763
2764 if (copy_from_user(&fd, data, sizeof(fd)))
2765 return -EFAULT;
2766
2767 if (fd == -1) {
2768 prog = NULL;
2769 } else {
2770 prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
2771 if (IS_ERR(prog))
2772 return PTR_ERR(prog);
2773 }
2774
2775 return __tun_set_ebpf(tun, prog_p, prog);
2776 }
2777
2778 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
2779 unsigned long arg, int ifreq_len)
2780 {
2781 struct tun_file *tfile = file->private_data;
2782 struct tun_struct *tun;
2783 void __user* argp = (void __user*)arg;
2784 struct ifreq ifr;
2785 kuid_t owner;
2786 kgid_t group;
2787 int sndbuf;
2788 int vnet_hdr_sz;
2789 unsigned int ifindex;
2790 int le;
2791 int ret;
2792
2793 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == SOCK_IOC_TYPE) {
2794 if (copy_from_user(&ifr, argp, ifreq_len))
2795 return -EFAULT;
2796 } else {
2797 memset(&ifr, 0, sizeof(ifr));
2798 }
2799 if (cmd == TUNGETFEATURES) {
2800 /* Currently this just means: "what IFF flags are valid?".
2801 * This is needed because we never checked for invalid flags on
2802 * TUNSETIFF.
2803 */
2804 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
2805 (unsigned int __user*)argp);
2806 } else if (cmd == TUNSETQUEUE)
2807 return tun_set_queue(file, &ifr);
2808
2809 ret = 0;
2810 rtnl_lock();
2811
2812 tun = tun_get(tfile);
2813 if (cmd == TUNSETIFF) {
2814 ret = -EEXIST;
2815 if (tun)
2816 goto unlock;
2817
2818 ifr.ifr_name[IFNAMSIZ-1] = '\0';
2819
2820 ret = tun_set_iff(sock_net(&tfile->sk), file, &ifr);
2821
2822 if (ret)
2823 goto unlock;
2824
2825 if (copy_to_user(argp, &ifr, ifreq_len))
2826 ret = -EFAULT;
2827 goto unlock;
2828 }
2829 if (cmd == TUNSETIFINDEX) {
2830 ret = -EPERM;
2831 if (tun)
2832 goto unlock;
2833
2834 ret = -EFAULT;
2835 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
2836 goto unlock;
2837
2838 ret = 0;
2839 tfile->ifindex = ifindex;
2840 goto unlock;
2841 }
2842
2843 ret = -EBADFD;
2844 if (!tun)
2845 goto unlock;
2846
2847 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
2848
2849 ret = 0;
2850 switch (cmd) {
2851 case TUNGETIFF:
2852 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2853
2854 if (tfile->detached)
2855 ifr.ifr_flags |= IFF_DETACH_QUEUE;
2856 if (!tfile->socket.sk->sk_filter)
2857 ifr.ifr_flags |= IFF_NOFILTER;
2858
2859 if (copy_to_user(argp, &ifr, ifreq_len))
2860 ret = -EFAULT;
2861 break;
2862
2863 case TUNSETNOCSUM:
2864 /* Disable/Enable checksum */
2865
2866 /* [unimplemented] */
2867 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
2868 arg ? "disabled" : "enabled");
2869 break;
2870
2871 case TUNSETPERSIST:
2872 /* Disable/Enable persist mode. Keep an extra reference to the
2873 * module to prevent the module being unprobed.
2874 */
2875 if (arg && !(tun->flags & IFF_PERSIST)) {
2876 tun->flags |= IFF_PERSIST;
2877 __module_get(THIS_MODULE);
2878 }
2879 if (!arg && (tun->flags & IFF_PERSIST)) {
2880 tun->flags &= ~IFF_PERSIST;
2881 module_put(THIS_MODULE);
2882 }
2883
2884 tun_debug(KERN_INFO, tun, "persist %s\n",
2885 arg ? "enabled" : "disabled");
2886 break;
2887
2888 case TUNSETOWNER:
2889 /* Set owner of the device */
2890 owner = make_kuid(current_user_ns(), arg);
2891 if (!uid_valid(owner)) {
2892 ret = -EINVAL;
2893 break;
2894 }
2895 tun->owner = owner;
2896 tun_debug(KERN_INFO, tun, "owner set to %u\n",
2897 from_kuid(&init_user_ns, tun->owner));
2898 break;
2899
2900 case TUNSETGROUP:
2901 /* Set group of the device */
2902 group = make_kgid(current_user_ns(), arg);
2903 if (!gid_valid(group)) {
2904 ret = -EINVAL;
2905 break;
2906 }
2907 tun->group = group;
2908 tun_debug(KERN_INFO, tun, "group set to %u\n",
2909 from_kgid(&init_user_ns, tun->group));
2910 break;
2911
2912 case TUNSETLINK:
2913 /* Only allow setting the type when the interface is down */
2914 if (tun->dev->flags & IFF_UP) {
2915 tun_debug(KERN_INFO, tun,
2916 "Linktype set failed because interface is up\n");
2917 ret = -EBUSY;
2918 } else {
2919 tun->dev->type = (int) arg;
2920 tun_debug(KERN_INFO, tun, "linktype set to %d\n",
2921 tun->dev->type);
2922 ret = 0;
2923 }
2924 break;
2925
2926 #ifdef TUN_DEBUG
2927 case TUNSETDEBUG:
2928 tun->debug = arg;
2929 break;
2930 #endif
2931 case TUNSETOFFLOAD:
2932 ret = set_offload(tun, arg);
2933 break;
2934
2935 case TUNSETTXFILTER:
2936 /* Can be set only for TAPs */
2937 ret = -EINVAL;
2938 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2939 break;
2940 ret = update_filter(&tun->txflt, (void __user *)arg);
2941 break;
2942
2943 case SIOCGIFHWADDR:
2944 /* Get hw address */
2945 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
2946 ifr.ifr_hwaddr.sa_family = tun->dev->type;
2947 if (copy_to_user(argp, &ifr, ifreq_len))
2948 ret = -EFAULT;
2949 break;
2950
2951 case SIOCSIFHWADDR:
2952 /* Set hw address */
2953 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
2954 ifr.ifr_hwaddr.sa_data);
2955
2956 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
2957 break;
2958
2959 case TUNGETSNDBUF:
2960 sndbuf = tfile->socket.sk->sk_sndbuf;
2961 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
2962 ret = -EFAULT;
2963 break;
2964
2965 case TUNSETSNDBUF:
2966 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
2967 ret = -EFAULT;
2968 break;
2969 }
2970 if (sndbuf <= 0) {
2971 ret = -EINVAL;
2972 break;
2973 }
2974
2975 tun->sndbuf = sndbuf;
2976 tun_set_sndbuf(tun);
2977 break;
2978
2979 case TUNGETVNETHDRSZ:
2980 vnet_hdr_sz = tun->vnet_hdr_sz;
2981 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
2982 ret = -EFAULT;
2983 break;
2984
2985 case TUNSETVNETHDRSZ:
2986 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
2987 ret = -EFAULT;
2988 break;
2989 }
2990 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
2991 ret = -EINVAL;
2992 break;
2993 }
2994
2995 tun->vnet_hdr_sz = vnet_hdr_sz;
2996 break;
2997
2998 case TUNGETVNETLE:
2999 le = !!(tun->flags & TUN_VNET_LE);
3000 if (put_user(le, (int __user *)argp))
3001 ret = -EFAULT;
3002 break;
3003
3004 case TUNSETVNETLE:
3005 if (get_user(le, (int __user *)argp)) {
3006 ret = -EFAULT;
3007 break;
3008 }
3009 if (le)
3010 tun->flags |= TUN_VNET_LE;
3011 else
3012 tun->flags &= ~TUN_VNET_LE;
3013 break;
3014
3015 case TUNGETVNETBE:
3016 ret = tun_get_vnet_be(tun, argp);
3017 break;
3018
3019 case TUNSETVNETBE:
3020 ret = tun_set_vnet_be(tun, argp);
3021 break;
3022
3023 case TUNATTACHFILTER:
3024 /* Can be set only for TAPs */
3025 ret = -EINVAL;
3026 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3027 break;
3028 ret = -EFAULT;
3029 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
3030 break;
3031
3032 ret = tun_attach_filter(tun);
3033 break;
3034
3035 case TUNDETACHFILTER:
3036 /* Can be set only for TAPs */
3037 ret = -EINVAL;
3038 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3039 break;
3040 ret = 0;
3041 tun_detach_filter(tun, tun->numqueues);
3042 break;
3043
3044 case TUNGETFILTER:
3045 ret = -EINVAL;
3046 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3047 break;
3048 ret = -EFAULT;
3049 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
3050 break;
3051 ret = 0;
3052 break;
3053
3054 case TUNSETSTEERINGEBPF:
3055 ret = tun_set_ebpf(tun, &tun->steering_prog, argp);
3056 break;
3057
3058 case TUNSETFILTEREBPF:
3059 ret = tun_set_ebpf(tun, &tun->filter_prog, argp);
3060 break;
3061
3062 default:
3063 ret = -EINVAL;
3064 break;
3065 }
3066
3067 unlock:
3068 rtnl_unlock();
3069 if (tun)
3070 tun_put(tun);
3071 return ret;
3072 }
3073
3074 static long tun_chr_ioctl(struct file *file,
3075 unsigned int cmd, unsigned long arg)
3076 {
3077 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
3078 }
3079
3080 #ifdef CONFIG_COMPAT
3081 static long tun_chr_compat_ioctl(struct file *file,
3082 unsigned int cmd, unsigned long arg)
3083 {
3084 switch (cmd) {
3085 case TUNSETIFF:
3086 case TUNGETIFF:
3087 case TUNSETTXFILTER:
3088 case TUNGETSNDBUF:
3089 case TUNSETSNDBUF:
3090 case SIOCGIFHWADDR:
3091 case SIOCSIFHWADDR:
3092 arg = (unsigned long)compat_ptr(arg);
3093 break;
3094 default:
3095 arg = (compat_ulong_t)arg;
3096 break;
3097 }
3098
3099 /*
3100 * compat_ifreq is shorter than ifreq, so we must not access beyond
3101 * the end of that structure. All fields that are used in this
3102 * driver are compatible though, we don't need to convert the
3103 * contents.
3104 */
3105 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
3106 }
3107 #endif /* CONFIG_COMPAT */
3108
3109 static int tun_chr_fasync(int fd, struct file *file, int on)
3110 {
3111 struct tun_file *tfile = file->private_data;
3112 int ret;
3113
3114 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
3115 goto out;
3116
3117 if (on) {
3118 __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
3119 tfile->flags |= TUN_FASYNC;
3120 } else
3121 tfile->flags &= ~TUN_FASYNC;
3122 ret = 0;
3123 out:
3124 return ret;
3125 }
3126
3127 static int tun_chr_open(struct inode *inode, struct file * file)
3128 {
3129 struct net *net = current->nsproxy->net_ns;
3130 struct tun_file *tfile;
3131
3132 DBG1(KERN_INFO, "tunX: tun_chr_open\n");
3133
3134 tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
3135 &tun_proto, 0);
3136 if (!tfile)
3137 return -ENOMEM;
3138 RCU_INIT_POINTER(tfile->tun, NULL);
3139 tfile->flags = 0;
3140 tfile->ifindex = 0;
3141
3142 init_waitqueue_head(&tfile->wq.wait);
3143 RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq);
3144
3145 tfile->socket.file = file;
3146 tfile->socket.ops = &tun_socket_ops;
3147
3148 sock_init_data(&tfile->socket, &tfile->sk);
3149
3150 tfile->sk.sk_write_space = tun_sock_write_space;
3151 tfile->sk.sk_sndbuf = INT_MAX;
3152
3153 file->private_data = tfile;
3154 INIT_LIST_HEAD(&tfile->next);
3155
3156 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
3157
3158 memset(&tfile->tx_ring, 0, sizeof(tfile->tx_ring));
3159
3160 return 0;
3161 }
3162
3163 static int tun_chr_close(struct inode *inode, struct file *file)
3164 {
3165 struct tun_file *tfile = file->private_data;
3166
3167 tun_detach(tfile, true);
3168
3169 return 0;
3170 }
3171
3172 #ifdef CONFIG_PROC_FS
3173 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *file)
3174 {
3175 struct tun_file *tfile = file->private_data;
3176 struct tun_struct *tun;
3177 struct ifreq ifr;
3178
3179 memset(&ifr, 0, sizeof(ifr));
3180
3181 rtnl_lock();
3182 tun = tun_get(tfile);
3183 if (tun)
3184 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
3185 rtnl_unlock();
3186
3187 if (tun)
3188 tun_put(tun);
3189
3190 seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
3191 }
3192 #endif
3193
3194 static const struct file_operations tun_fops = {
3195 .owner = THIS_MODULE,
3196 .llseek = no_llseek,
3197 .read_iter = tun_chr_read_iter,
3198 .write_iter = tun_chr_write_iter,
3199 .poll = tun_chr_poll,
3200 .unlocked_ioctl = tun_chr_ioctl,
3201 #ifdef CONFIG_COMPAT
3202 .compat_ioctl = tun_chr_compat_ioctl,
3203 #endif
3204 .open = tun_chr_open,
3205 .release = tun_chr_close,
3206 .fasync = tun_chr_fasync,
3207 #ifdef CONFIG_PROC_FS
3208 .show_fdinfo = tun_chr_show_fdinfo,
3209 #endif
3210 };
3211
3212 static struct miscdevice tun_miscdev = {
3213 .minor = TUN_MINOR,
3214 .name = "tun",
3215 .nodename = "net/tun",
3216 .fops = &tun_fops,
3217 };
3218
3219 /* ethtool interface */
3220
3221 static int tun_get_link_ksettings(struct net_device *dev,
3222 struct ethtool_link_ksettings *cmd)
3223 {
3224 ethtool_link_ksettings_zero_link_mode(cmd, supported);
3225 ethtool_link_ksettings_zero_link_mode(cmd, advertising);
3226 cmd->base.speed = SPEED_10;
3227 cmd->base.duplex = DUPLEX_FULL;
3228 cmd->base.port = PORT_TP;
3229 cmd->base.phy_address = 0;
3230 cmd->base.autoneg = AUTONEG_DISABLE;
3231 return 0;
3232 }
3233
3234 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
3235 {
3236 struct tun_struct *tun = netdev_priv(dev);
3237
3238 strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
3239 strlcpy(info->version, DRV_VERSION, sizeof(info->version));
3240
3241 switch (tun->flags & TUN_TYPE_MASK) {
3242 case IFF_TUN:
3243 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
3244 break;
3245 case IFF_TAP:
3246 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
3247 break;
3248 }
3249 }
3250
3251 static u32 tun_get_msglevel(struct net_device *dev)
3252 {
3253 #ifdef TUN_DEBUG
3254 struct tun_struct *tun = netdev_priv(dev);
3255 return tun->debug;
3256 #else
3257 return -EOPNOTSUPP;
3258 #endif
3259 }
3260
3261 static void tun_set_msglevel(struct net_device *dev, u32 value)
3262 {
3263 #ifdef TUN_DEBUG
3264 struct tun_struct *tun = netdev_priv(dev);
3265 tun->debug = value;
3266 #endif
3267 }
3268
3269 static int tun_get_coalesce(struct net_device *dev,
3270 struct ethtool_coalesce *ec)
3271 {
3272 struct tun_struct *tun = netdev_priv(dev);
3273
3274 ec->rx_max_coalesced_frames = tun->rx_batched;
3275
3276 return 0;
3277 }
3278
3279 static int tun_set_coalesce(struct net_device *dev,
3280 struct ethtool_coalesce *ec)
3281 {
3282 struct tun_struct *tun = netdev_priv(dev);
3283
3284 if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT)
3285 tun->rx_batched = NAPI_POLL_WEIGHT;
3286 else
3287 tun->rx_batched = ec->rx_max_coalesced_frames;
3288
3289 return 0;
3290 }
3291
3292 static const struct ethtool_ops tun_ethtool_ops = {
3293 .get_drvinfo = tun_get_drvinfo,
3294 .get_msglevel = tun_get_msglevel,
3295 .set_msglevel = tun_set_msglevel,
3296 .get_link = ethtool_op_get_link,
3297 .get_ts_info = ethtool_op_get_ts_info,
3298 .get_coalesce = tun_get_coalesce,
3299 .set_coalesce = tun_set_coalesce,
3300 .get_link_ksettings = tun_get_link_ksettings,
3301 };
3302
3303 static int tun_queue_resize(struct tun_struct *tun)
3304 {
3305 struct net_device *dev = tun->dev;
3306 struct tun_file *tfile;
3307 struct ptr_ring **rings;
3308 int n = tun->numqueues + tun->numdisabled;
3309 int ret, i;
3310
3311 rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL);
3312 if (!rings)
3313 return -ENOMEM;
3314
3315 for (i = 0; i < tun->numqueues; i++) {
3316 tfile = rtnl_dereference(tun->tfiles[i]);
3317 rings[i] = &tfile->tx_ring;
3318 }
3319 list_for_each_entry(tfile, &tun->disabled, next)
3320 rings[i++] = &tfile->tx_ring;
3321
3322 ret = ptr_ring_resize_multiple(rings, n,
3323 dev->tx_queue_len, GFP_KERNEL,
3324 tun_ptr_free);
3325
3326 kfree(rings);
3327 return ret;
3328 }
3329
3330 static int tun_device_event(struct notifier_block *unused,
3331 unsigned long event, void *ptr)
3332 {
3333 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3334 struct tun_struct *tun = netdev_priv(dev);
3335
3336 if (dev->rtnl_link_ops != &tun_link_ops)
3337 return NOTIFY_DONE;
3338
3339 switch (event) {
3340 case NETDEV_CHANGE_TX_QUEUE_LEN:
3341 if (tun_queue_resize(tun))
3342 return NOTIFY_BAD;
3343 break;
3344 default:
3345 break;
3346 }
3347
3348 return NOTIFY_DONE;
3349 }
3350
3351 static struct notifier_block tun_notifier_block __read_mostly = {
3352 .notifier_call = tun_device_event,
3353 };
3354
3355 static int __init tun_init(void)
3356 {
3357 int ret = 0;
3358
3359 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
3360
3361 ret = rtnl_link_register(&tun_link_ops);
3362 if (ret) {
3363 pr_err("Can't register link_ops\n");
3364 goto err_linkops;
3365 }
3366
3367 ret = misc_register(&tun_miscdev);
3368 if (ret) {
3369 pr_err("Can't register misc device %d\n", TUN_MINOR);
3370 goto err_misc;
3371 }
3372
3373 ret = register_netdevice_notifier(&tun_notifier_block);
3374 if (ret) {
3375 pr_err("Can't register netdevice notifier\n");
3376 goto err_notifier;
3377 }
3378
3379 return 0;
3380
3381 err_notifier:
3382 misc_deregister(&tun_miscdev);
3383 err_misc:
3384 rtnl_link_unregister(&tun_link_ops);
3385 err_linkops:
3386 return ret;
3387 }
3388
3389 static void tun_cleanup(void)
3390 {
3391 misc_deregister(&tun_miscdev);
3392 rtnl_link_unregister(&tun_link_ops);
3393 unregister_netdevice_notifier(&tun_notifier_block);
3394 }
3395
3396 /* Get an underlying socket object from tun file. Returns error unless file is
3397 * attached to a device. The returned object works like a packet socket, it
3398 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
3399 * holding a reference to the file for as long as the socket is in use. */
3400 struct socket *tun_get_socket(struct file *file)
3401 {
3402 struct tun_file *tfile;
3403 if (file->f_op != &tun_fops)
3404 return ERR_PTR(-EINVAL);
3405 tfile = file->private_data;
3406 if (!tfile)
3407 return ERR_PTR(-EBADFD);
3408 return &tfile->socket;
3409 }
3410 EXPORT_SYMBOL_GPL(tun_get_socket);
3411
3412 struct ptr_ring *tun_get_tx_ring(struct file *file)
3413 {
3414 struct tun_file *tfile;
3415
3416 if (file->f_op != &tun_fops)
3417 return ERR_PTR(-EINVAL);
3418 tfile = file->private_data;
3419 if (!tfile)
3420 return ERR_PTR(-EBADFD);
3421 return &tfile->tx_ring;
3422 }
3423 EXPORT_SYMBOL_GPL(tun_get_tx_ring);
3424
3425 module_init(tun_init);
3426 module_exit(tun_cleanup);
3427 MODULE_DESCRIPTION(DRV_DESCRIPTION);
3428 MODULE_AUTHOR(DRV_COPYRIGHT);
3429 MODULE_LICENSE("GPL");
3430 MODULE_ALIAS_MISCDEV(TUN_MINOR);
3431 MODULE_ALIAS("devname:net/tun");
CRIS linux kernel tree