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Merge tag 'for-linus-20190706' of git://git.kernel.dk/linux-block
[linux/fpc-iii.git] / drivers / net / tun.c
blobd7c55e0fa8f4fa58bf723a066c81fab684973b7e
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 /* Uncomment to enable debugging */
79 /* #define TUN_DEBUG 1 */
80
81 #ifdef TUN_DEBUG
82 static int debug;
83
84 #define tun_debug(level, tun, fmt, args...) \
85 do { \
86 if (tun->debug) \
87 netdev_printk(level, tun->dev, fmt, ##args); \
88 } while (0)
89 #define DBG1(level, fmt, args...) \
90 do { \
91 if (debug == 2) \
92 printk(level fmt, ##args); \
93 } while (0)
94 #else
95 #define tun_debug(level, tun, fmt, args...) \
96 do { \
97 if (0) \
98 netdev_printk(level, tun->dev, fmt, ##args); \
99 } while (0)
100 #define DBG1(level, fmt, args...) \
101 do { \
102 if (0) \
103 printk(level fmt, ##args); \
104 } while (0)
105 #endif
106
107 #define TUN_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
108
109 /* TUN device flags */
110
111 /* IFF_ATTACH_QUEUE is never stored in device flags,
112 * overload it to mean fasync when stored there.
113 */
114 #define TUN_FASYNC IFF_ATTACH_QUEUE
115 /* High bits in flags field are unused. */
116 #define TUN_VNET_LE 0x80000000
117 #define TUN_VNET_BE 0x40000000
118
119 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
120 IFF_MULTI_QUEUE | IFF_NAPI | IFF_NAPI_FRAGS)
121
122 #define GOODCOPY_LEN 128
123
124 #define FLT_EXACT_COUNT 8
125 struct tap_filter {
126 unsigned int count; /* Number of addrs. Zero means disabled */
127 u32 mask[2]; /* Mask of the hashed addrs */
128 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
129 };
130
131 /* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
132 * to max number of VCPUs in guest. */
133 #define MAX_TAP_QUEUES 256
134 #define MAX_TAP_FLOWS 4096
135
136 #define TUN_FLOW_EXPIRE (3 * HZ)
137
138 struct tun_pcpu_stats {
139 u64 rx_packets;
140 u64 rx_bytes;
141 u64 tx_packets;
142 u64 tx_bytes;
143 struct u64_stats_sync syncp;
144 u32 rx_dropped;
145 u32 tx_dropped;
146 u32 rx_frame_errors;
147 };
148
149 /* A tun_file connects an open character device to a tuntap netdevice. It
150 * also contains all socket related structures (except sock_fprog and tap_filter)
151 * to serve as one transmit queue for tuntap device. The sock_fprog and
152 * tap_filter were kept in tun_struct since they were used for filtering for the
153 * netdevice not for a specific queue (at least I didn't see the requirement for
154 * this).
155 *
156 * RCU usage:
157 * The tun_file and tun_struct are loosely coupled, the pointer from one to the
158 * other can only be read while rcu_read_lock or rtnl_lock is held.
159 */
160 struct tun_file {
161 struct sock sk;
162 struct socket socket;
163 struct socket_wq wq;
164 struct tun_struct __rcu *tun;
165 struct fasync_struct *fasync;
166 /* only used for fasnyc */
167 unsigned int flags;
168 union {
169 u16 queue_index;
170 unsigned int ifindex;
171 };
172 struct napi_struct napi;
173 bool napi_enabled;
174 bool napi_frags_enabled;
175 struct mutex napi_mutex; /* Protects access to the above napi */
176 struct list_head next;
177 struct tun_struct *detached;
178 struct ptr_ring tx_ring;
179 struct xdp_rxq_info xdp_rxq;
180 };
181
182 struct tun_page {
183 struct page *page;
184 int count;
185 };
186
187 struct tun_flow_entry {
188 struct hlist_node hash_link;
189 struct rcu_head rcu;
190 struct tun_struct *tun;
191
192 u32 rxhash;
193 u32 rps_rxhash;
194 int queue_index;
195 unsigned long updated ____cacheline_aligned_in_smp;
196 };
197
198 #define TUN_NUM_FLOW_ENTRIES 1024
199 #define TUN_MASK_FLOW_ENTRIES (TUN_NUM_FLOW_ENTRIES - 1)
200
201 struct tun_prog {
202 struct rcu_head rcu;
203 struct bpf_prog *prog;
204 };
205
206 /* Since the socket were moved to tun_file, to preserve the behavior of persist
207 * device, socket filter, sndbuf and vnet header size were restore when the
208 * file were attached to a persist device.
209 */
210 struct tun_struct {
211 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES];
212 unsigned int numqueues;
213 unsigned int flags;
214 kuid_t owner;
215 kgid_t group;
216
217 struct net_device *dev;
218 netdev_features_t set_features;
219 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
220 NETIF_F_TSO6)
221
222 int align;
223 int vnet_hdr_sz;
224 int sndbuf;
225 struct tap_filter txflt;
226 struct sock_fprog fprog;
227 /* protected by rtnl lock */
228 bool filter_attached;
229 #ifdef TUN_DEBUG
230 int debug;
231 #endif
232 spinlock_t lock;
233 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
234 struct timer_list flow_gc_timer;
235 unsigned long ageing_time;
236 unsigned int numdisabled;
237 struct list_head disabled;
238 void *security;
239 u32 flow_count;
240 u32 rx_batched;
241 struct tun_pcpu_stats __percpu *pcpu_stats;
242 struct bpf_prog __rcu *xdp_prog;
243 struct tun_prog __rcu *steering_prog;
244 struct tun_prog __rcu *filter_prog;
245 struct ethtool_link_ksettings link_ksettings;
246 };
247
248 struct veth {
249 __be16 h_vlan_proto;
250 __be16 h_vlan_TCI;
251 };
252
253 bool tun_is_xdp_frame(void *ptr)
254 {
255 return (unsigned long)ptr & TUN_XDP_FLAG;
256 }
257 EXPORT_SYMBOL(tun_is_xdp_frame);
258
259 void *tun_xdp_to_ptr(void *ptr)
260 {
261 return (void *)((unsigned long)ptr | TUN_XDP_FLAG);
262 }
263 EXPORT_SYMBOL(tun_xdp_to_ptr);
264
265 void *tun_ptr_to_xdp(void *ptr)
266 {
267 return (void *)((unsigned long)ptr & ~TUN_XDP_FLAG);
268 }
269 EXPORT_SYMBOL(tun_ptr_to_xdp);
270
271 static int tun_napi_receive(struct napi_struct *napi, int budget)
272 {
273 struct tun_file *tfile = container_of(napi, struct tun_file, napi);
274 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
275 struct sk_buff_head process_queue;
276 struct sk_buff *skb;
277 int received = 0;
278
279 __skb_queue_head_init(&process_queue);
280
281 spin_lock(&queue->lock);
282 skb_queue_splice_tail_init(queue, &process_queue);
283 spin_unlock(&queue->lock);
284
285 while (received < budget && (skb = __skb_dequeue(&process_queue))) {
286 napi_gro_receive(napi, skb);
287 ++received;
288 }
289
290 if (!skb_queue_empty(&process_queue)) {
291 spin_lock(&queue->lock);
292 skb_queue_splice(&process_queue, queue);
293 spin_unlock(&queue->lock);
294 }
295
296 return received;
297 }
298
299 static int tun_napi_poll(struct napi_struct *napi, int budget)
300 {
301 unsigned int received;
302
303 received = tun_napi_receive(napi, budget);
304
305 if (received < budget)
306 napi_complete_done(napi, received);
307
308 return received;
309 }
310
311 static void tun_napi_init(struct tun_struct *tun, struct tun_file *tfile,
312 bool napi_en, bool napi_frags)
313 {
314 tfile->napi_enabled = napi_en;
315 tfile->napi_frags_enabled = napi_en && napi_frags;
316 if (napi_en) {
317 netif_napi_add(tun->dev, &tfile->napi, tun_napi_poll,
318 NAPI_POLL_WEIGHT);
319 napi_enable(&tfile->napi);
320 }
321 }
322
323 static void tun_napi_disable(struct tun_file *tfile)
324 {
325 if (tfile->napi_enabled)
326 napi_disable(&tfile->napi);
327 }
328
329 static void tun_napi_del(struct tun_file *tfile)
330 {
331 if (tfile->napi_enabled)
332 netif_napi_del(&tfile->napi);
333 }
334
335 static bool tun_napi_frags_enabled(const struct tun_file *tfile)
336 {
337 return tfile->napi_frags_enabled;
338 }
339
340 #ifdef CONFIG_TUN_VNET_CROSS_LE
341 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
342 {
343 return tun->flags & TUN_VNET_BE ? false :
344 virtio_legacy_is_little_endian();
345 }
346
347 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
348 {
349 int be = !!(tun->flags & TUN_VNET_BE);
350
351 if (put_user(be, argp))
352 return -EFAULT;
353
354 return 0;
355 }
356
357 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
358 {
359 int be;
360
361 if (get_user(be, argp))
362 return -EFAULT;
363
364 if (be)
365 tun->flags |= TUN_VNET_BE;
366 else
367 tun->flags &= ~TUN_VNET_BE;
368
369 return 0;
370 }
371 #else
372 static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
373 {
374 return virtio_legacy_is_little_endian();
375 }
376
377 static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
378 {
379 return -EINVAL;
380 }
381
382 static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
383 {
384 return -EINVAL;
385 }
386 #endif /* CONFIG_TUN_VNET_CROSS_LE */
387
388 static inline bool tun_is_little_endian(struct tun_struct *tun)
389 {
390 return tun->flags & TUN_VNET_LE ||
391 tun_legacy_is_little_endian(tun);
392 }
393
394 static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
395 {
396 return __virtio16_to_cpu(tun_is_little_endian(tun), val);
397 }
398
399 static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
400 {
401 return __cpu_to_virtio16(tun_is_little_endian(tun), val);
402 }
403
404 static inline u32 tun_hashfn(u32 rxhash)
405 {
406 return rxhash & TUN_MASK_FLOW_ENTRIES;
407 }
408
409 static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
410 {
411 struct tun_flow_entry *e;
412
413 hlist_for_each_entry_rcu(e, head, hash_link) {
414 if (e->rxhash == rxhash)
415 return e;
416 }
417 return NULL;
418 }
419
420 static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
421 struct hlist_head *head,
422 u32 rxhash, u16 queue_index)
423 {
424 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
425
426 if (e) {
427 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
428 rxhash, queue_index);
429 e->updated = jiffies;
430 e->rxhash = rxhash;
431 e->rps_rxhash = 0;
432 e->queue_index = queue_index;
433 e->tun = tun;
434 hlist_add_head_rcu(&e->hash_link, head);
435 ++tun->flow_count;
436 }
437 return e;
438 }
439
440 static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
441 {
442 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
443 e->rxhash, e->queue_index);
444 hlist_del_rcu(&e->hash_link);
445 kfree_rcu(e, rcu);
446 --tun->flow_count;
447 }
448
449 static void tun_flow_flush(struct tun_struct *tun)
450 {
451 int i;
452
453 spin_lock_bh(&tun->lock);
454 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
455 struct tun_flow_entry *e;
456 struct hlist_node *n;
457
458 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
459 tun_flow_delete(tun, e);
460 }
461 spin_unlock_bh(&tun->lock);
462 }
463
464 static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
465 {
466 int i;
467
468 spin_lock_bh(&tun->lock);
469 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
470 struct tun_flow_entry *e;
471 struct hlist_node *n;
472
473 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
474 if (e->queue_index == queue_index)
475 tun_flow_delete(tun, e);
476 }
477 }
478 spin_unlock_bh(&tun->lock);
479 }
480
481 static void tun_flow_cleanup(struct timer_list *t)
482 {
483 struct tun_struct *tun = from_timer(tun, t, flow_gc_timer);
484 unsigned long delay = tun->ageing_time;
485 unsigned long next_timer = jiffies + delay;
486 unsigned long count = 0;
487 int i;
488
489 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
490
491 spin_lock(&tun->lock);
492 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
493 struct tun_flow_entry *e;
494 struct hlist_node *n;
495
496 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
497 unsigned long this_timer;
498
499 this_timer = e->updated + delay;
500 if (time_before_eq(this_timer, jiffies)) {
501 tun_flow_delete(tun, e);
502 continue;
503 }
504 count++;
505 if (time_before(this_timer, next_timer))
506 next_timer = this_timer;
507 }
508 }
509
510 if (count)
511 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
512 spin_unlock(&tun->lock);
513 }
514
515 static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
516 struct tun_file *tfile)
517 {
518 struct hlist_head *head;
519 struct tun_flow_entry *e;
520 unsigned long delay = tun->ageing_time;
521 u16 queue_index = tfile->queue_index;
522
523 head = &tun->flows[tun_hashfn(rxhash)];
524
525 rcu_read_lock();
526
527 e = tun_flow_find(head, rxhash);
528 if (likely(e)) {
529 /* TODO: keep queueing to old queue until it's empty? */
530 if (e->queue_index != queue_index)
531 e->queue_index = queue_index;
532 if (e->updated != jiffies)
533 e->updated = jiffies;
534 sock_rps_record_flow_hash(e->rps_rxhash);
535 } else {
536 spin_lock_bh(&tun->lock);
537 if (!tun_flow_find(head, rxhash) &&
538 tun->flow_count < MAX_TAP_FLOWS)
539 tun_flow_create(tun, head, rxhash, queue_index);
540
541 if (!timer_pending(&tun->flow_gc_timer))
542 mod_timer(&tun->flow_gc_timer,
543 round_jiffies_up(jiffies + delay));
544 spin_unlock_bh(&tun->lock);
545 }
546
547 rcu_read_unlock();
548 }
549
550 /**
551 * Save the hash received in the stack receive path and update the
552 * flow_hash table accordingly.
553 */
554 static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
555 {
556 if (unlikely(e->rps_rxhash != hash))
557 e->rps_rxhash = hash;
558 }
559
560 /* We try to identify a flow through its rxhash. The reason that
561 * we do not check rxq no. is because some cards(e.g 82599), chooses
562 * the rxq based on the txq where the last packet of the flow comes. As
563 * the userspace application move between processors, we may get a
564 * different rxq no. here.
565 */
566 static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb)
567 {
568 struct tun_flow_entry *e;
569 u32 txq = 0;
570 u32 numqueues = 0;
571
572 numqueues = READ_ONCE(tun->numqueues);
573
574 txq = __skb_get_hash_symmetric(skb);
575 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
576 if (e) {
577 tun_flow_save_rps_rxhash(e, txq);
578 txq = e->queue_index;
579 } else {
580 /* use multiply and shift instead of expensive divide */
581 txq = ((u64)txq * numqueues) >> 32;
582 }
583
584 return txq;
585 }
586
587 static u16 tun_ebpf_select_queue(struct tun_struct *tun, struct sk_buff *skb)
588 {
589 struct tun_prog *prog;
590 u32 numqueues;
591 u16 ret = 0;
592
593 numqueues = READ_ONCE(tun->numqueues);
594 if (!numqueues)
595 return 0;
596
597 prog = rcu_dereference(tun->steering_prog);
598 if (prog)
599 ret = bpf_prog_run_clear_cb(prog->prog, skb);
600
601 return ret % numqueues;
602 }
603
604 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
605 struct net_device *sb_dev)
606 {
607 struct tun_struct *tun = netdev_priv(dev);
608 u16 ret;
609
610 rcu_read_lock();
611 if (rcu_dereference(tun->steering_prog))
612 ret = tun_ebpf_select_queue(tun, skb);
613 else
614 ret = tun_automq_select_queue(tun, skb);
615 rcu_read_unlock();
616
617 return ret;
618 }
619
620 static inline bool tun_not_capable(struct tun_struct *tun)
621 {
622 const struct cred *cred = current_cred();
623 struct net *net = dev_net(tun->dev);
624
625 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
626 (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
627 !ns_capable(net->user_ns, CAP_NET_ADMIN);
628 }
629
630 static void tun_set_real_num_queues(struct tun_struct *tun)
631 {
632 netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
633 netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
634 }
635
636 static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
637 {
638 tfile->detached = tun;
639 list_add_tail(&tfile->next, &tun->disabled);
640 ++tun->numdisabled;
641 }
642
643 static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
644 {
645 struct tun_struct *tun = tfile->detached;
646
647 tfile->detached = NULL;
648 list_del_init(&tfile->next);
649 --tun->numdisabled;
650 return tun;
651 }
652
653 void tun_ptr_free(void *ptr)
654 {
655 if (!ptr)
656 return;
657 if (tun_is_xdp_frame(ptr)) {
658 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
659
660 xdp_return_frame(xdpf);
661 } else {
662 __skb_array_destroy_skb(ptr);
663 }
664 }
665 EXPORT_SYMBOL_GPL(tun_ptr_free);
666
667 static void tun_queue_purge(struct tun_file *tfile)
668 {
669 void *ptr;
670
671 while ((ptr = ptr_ring_consume(&tfile->tx_ring)) != NULL)
672 tun_ptr_free(ptr);
673
674 skb_queue_purge(&tfile->sk.sk_write_queue);
675 skb_queue_purge(&tfile->sk.sk_error_queue);
676 }
677
678 static void __tun_detach(struct tun_file *tfile, bool clean)
679 {
680 struct tun_file *ntfile;
681 struct tun_struct *tun;
682
683 tun = rtnl_dereference(tfile->tun);
684
685 if (tun && clean) {
686 tun_napi_disable(tfile);
687 tun_napi_del(tfile);
688 }
689
690 if (tun && !tfile->detached) {
691 u16 index = tfile->queue_index;
692 BUG_ON(index >= tun->numqueues);
693
694 rcu_assign_pointer(tun->tfiles[index],
695 tun->tfiles[tun->numqueues - 1]);
696 ntfile = rtnl_dereference(tun->tfiles[index]);
697 ntfile->queue_index = index;
698 rcu_assign_pointer(tun->tfiles[tun->numqueues - 1],
699 NULL);
700
701 --tun->numqueues;
702 if (clean) {
703 RCU_INIT_POINTER(tfile->tun, NULL);
704 sock_put(&tfile->sk);
705 } else
706 tun_disable_queue(tun, tfile);
707
708 synchronize_net();
709 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
710 /* Drop read queue */
711 tun_queue_purge(tfile);
712 tun_set_real_num_queues(tun);
713 } else if (tfile->detached && clean) {
714 tun = tun_enable_queue(tfile);
715 sock_put(&tfile->sk);
716 }
717
718 if (clean) {
719 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
720 netif_carrier_off(tun->dev);
721
722 if (!(tun->flags & IFF_PERSIST) &&
723 tun->dev->reg_state == NETREG_REGISTERED)
724 unregister_netdevice(tun->dev);
725 }
726 if (tun)
727 xdp_rxq_info_unreg(&tfile->xdp_rxq);
728 ptr_ring_cleanup(&tfile->tx_ring, tun_ptr_free);
729 sock_put(&tfile->sk);
730 }
731 }
732
733 static void tun_detach(struct tun_file *tfile, bool clean)
734 {
735 struct tun_struct *tun;
736 struct net_device *dev;
737
738 rtnl_lock();
739 tun = rtnl_dereference(tfile->tun);
740 dev = tun ? tun->dev : NULL;
741 __tun_detach(tfile, clean);
742 if (dev)
743 netdev_state_change(dev);
744 rtnl_unlock();
745 }
746
747 static void tun_detach_all(struct net_device *dev)
748 {
749 struct tun_struct *tun = netdev_priv(dev);
750 struct tun_file *tfile, *tmp;
751 int i, n = tun->numqueues;
752
753 for (i = 0; i < n; i++) {
754 tfile = rtnl_dereference(tun->tfiles[i]);
755 BUG_ON(!tfile);
756 tun_napi_disable(tfile);
757 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
758 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
759 RCU_INIT_POINTER(tfile->tun, NULL);
760 --tun->numqueues;
761 }
762 list_for_each_entry(tfile, &tun->disabled, next) {
763 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
764 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
765 RCU_INIT_POINTER(tfile->tun, NULL);
766 }
767 BUG_ON(tun->numqueues != 0);
768
769 synchronize_net();
770 for (i = 0; i < n; i++) {
771 tfile = rtnl_dereference(tun->tfiles[i]);
772 tun_napi_del(tfile);
773 /* Drop read queue */
774 tun_queue_purge(tfile);
775 xdp_rxq_info_unreg(&tfile->xdp_rxq);
776 sock_put(&tfile->sk);
777 }
778 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
779 tun_enable_queue(tfile);
780 tun_queue_purge(tfile);
781 xdp_rxq_info_unreg(&tfile->xdp_rxq);
782 sock_put(&tfile->sk);
783 }
784 BUG_ON(tun->numdisabled != 0);
785
786 if (tun->flags & IFF_PERSIST)
787 module_put(THIS_MODULE);
788 }
789
790 static int tun_attach(struct tun_struct *tun, struct file *file,
791 bool skip_filter, bool napi, bool napi_frags)
792 {
793 struct tun_file *tfile = file->private_data;
794 struct net_device *dev = tun->dev;
795 int err;
796
797 err = security_tun_dev_attach(tfile->socket.sk, tun->security);
798 if (err < 0)
799 goto out;
800
801 err = -EINVAL;
802 if (rtnl_dereference(tfile->tun) && !tfile->detached)
803 goto out;
804
805 err = -EBUSY;
806 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
807 goto out;
808
809 err = -E2BIG;
810 if (!tfile->detached &&
811 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
812 goto out;
813
814 err = 0;
815
816 /* Re-attach the filter to persist device */
817 if (!skip_filter && (tun->filter_attached == true)) {
818 lock_sock(tfile->socket.sk);
819 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
820 release_sock(tfile->socket.sk);
821 if (!err)
822 goto out;
823 }
824
825 if (!tfile->detached &&
826 ptr_ring_resize(&tfile->tx_ring, dev->tx_queue_len,
827 GFP_KERNEL, tun_ptr_free)) {
828 err = -ENOMEM;
829 goto out;
830 }
831
832 tfile->queue_index = tun->numqueues;
833 tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
834
835 if (tfile->detached) {
836 /* Re-attach detached tfile, updating XDP queue_index */
837 WARN_ON(!xdp_rxq_info_is_reg(&tfile->xdp_rxq));
838
839 if (tfile->xdp_rxq.queue_index != tfile->queue_index)
840 tfile->xdp_rxq.queue_index = tfile->queue_index;
841 } else {
842 /* Setup XDP RX-queue info, for new tfile getting attached */
843 err = xdp_rxq_info_reg(&tfile->xdp_rxq,
844 tun->dev, tfile->queue_index);
845 if (err < 0)
846 goto out;
847 err = xdp_rxq_info_reg_mem_model(&tfile->xdp_rxq,
848 MEM_TYPE_PAGE_SHARED, NULL);
849 if (err < 0) {
850 xdp_rxq_info_unreg(&tfile->xdp_rxq);
851 goto out;
852 }
853 err = 0;
854 }
855
856 if (tfile->detached) {
857 tun_enable_queue(tfile);
858 } else {
859 sock_hold(&tfile->sk);
860 tun_napi_init(tun, tfile, napi, napi_frags);
861 }
862
863 if (rtnl_dereference(tun->xdp_prog))
864 sock_set_flag(&tfile->sk, SOCK_XDP);
865
866 /* device is allowed to go away first, so no need to hold extra
867 * refcnt.
868 */
869
870 /* Publish tfile->tun and tun->tfiles only after we've fully
871 * initialized tfile; otherwise we risk using half-initialized
872 * object.
873 */
874 rcu_assign_pointer(tfile->tun, tun);
875 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
876 tun->numqueues++;
877 tun_set_real_num_queues(tun);
878 out:
879 return err;
880 }
881
882 static struct tun_struct *tun_get(struct tun_file *tfile)
883 {
884 struct tun_struct *tun;
885
886 rcu_read_lock();
887 tun = rcu_dereference(tfile->tun);
888 if (tun)
889 dev_hold(tun->dev);
890 rcu_read_unlock();
891
892 return tun;
893 }
894
895 static void tun_put(struct tun_struct *tun)
896 {
897 dev_put(tun->dev);
898 }
899
900 /* TAP filtering */
901 static void addr_hash_set(u32 *mask, const u8 *addr)
902 {
903 int n = ether_crc(ETH_ALEN, addr) >> 26;
904 mask[n >> 5] |= (1 << (n & 31));
905 }
906
907 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
908 {
909 int n = ether_crc(ETH_ALEN, addr) >> 26;
910 return mask[n >> 5] & (1 << (n & 31));
911 }
912
913 static int update_filter(struct tap_filter *filter, void __user *arg)
914 {
915 struct { u8 u[ETH_ALEN]; } *addr;
916 struct tun_filter uf;
917 int err, alen, n, nexact;
918
919 if (copy_from_user(&uf, arg, sizeof(uf)))
920 return -EFAULT;
921
922 if (!uf.count) {
923 /* Disabled */
924 filter->count = 0;
925 return 0;
926 }
927
928 alen = ETH_ALEN * uf.count;
929 addr = memdup_user(arg + sizeof(uf), alen);
930 if (IS_ERR(addr))
931 return PTR_ERR(addr);
932
933 /* The filter is updated without holding any locks. Which is
934 * perfectly safe. We disable it first and in the worst
935 * case we'll accept a few undesired packets. */
936 filter->count = 0;
937 wmb();
938
939 /* Use first set of addresses as an exact filter */
940 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
941 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
942
943 nexact = n;
944
945 /* Remaining multicast addresses are hashed,
946 * unicast will leave the filter disabled. */
947 memset(filter->mask, 0, sizeof(filter->mask));
948 for (; n < uf.count; n++) {
949 if (!is_multicast_ether_addr(addr[n].u)) {
950 err = 0; /* no filter */
951 goto free_addr;
952 }
953 addr_hash_set(filter->mask, addr[n].u);
954 }
955
956 /* For ALLMULTI just set the mask to all ones.
957 * This overrides the mask populated above. */
958 if ((uf.flags & TUN_FLT_ALLMULTI))
959 memset(filter->mask, ~0, sizeof(filter->mask));
960
961 /* Now enable the filter */
962 wmb();
963 filter->count = nexact;
964
965 /* Return the number of exact filters */
966 err = nexact;
967 free_addr:
968 kfree(addr);
969 return err;
970 }
971
972 /* Returns: 0 - drop, !=0 - accept */
973 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
974 {
975 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
976 * at this point. */
977 struct ethhdr *eh = (struct ethhdr *) skb->data;
978 int i;
979
980 /* Exact match */
981 for (i = 0; i < filter->count; i++)
982 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
983 return 1;
984
985 /* Inexact match (multicast only) */
986 if (is_multicast_ether_addr(eh->h_dest))
987 return addr_hash_test(filter->mask, eh->h_dest);
988
989 return 0;
990 }
991
992 /*
993 * Checks whether the packet is accepted or not.
994 * Returns: 0 - drop, !=0 - accept
995 */
996 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
997 {
998 if (!filter->count)
999 return 1;
1000
1001 return run_filter(filter, skb);
1002 }
1003
1004 /* Network device part of the driver */
1005
1006 static const struct ethtool_ops tun_ethtool_ops;
1007
1008 /* Net device detach from fd. */
1009 static void tun_net_uninit(struct net_device *dev)
1010 {
1011 tun_detach_all(dev);
1012 }
1013
1014 /* Net device open. */
1015 static int tun_net_open(struct net_device *dev)
1016 {
1017 netif_tx_start_all_queues(dev);
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_branch_unlikely(&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 struct tun_flow_entry *e;
1038 __u32 rxhash;
1039
1040 rxhash = __skb_get_hash_symmetric(skb);
1041 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)], rxhash);
1042 if (e)
1043 tun_flow_save_rps_rxhash(e, rxhash);
1044 }
1045 #endif
1046 }
1047
1048 static unsigned int run_ebpf_filter(struct tun_struct *tun,
1049 struct sk_buff *skb,
1050 int len)
1051 {
1052 struct tun_prog *prog = rcu_dereference(tun->filter_prog);
1053
1054 if (prog)
1055 len = bpf_prog_run_clear_cb(prog->prog, skb);
1056
1057 return len;
1058 }
1059
1060 /* Net device start xmit */
1061 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
1062 {
1063 struct tun_struct *tun = netdev_priv(dev);
1064 int txq = skb->queue_mapping;
1065 struct tun_file *tfile;
1066 int len = skb->len;
1067
1068 rcu_read_lock();
1069 tfile = rcu_dereference(tun->tfiles[txq]);
1070
1071 /* Drop packet if interface is not attached */
1072 if (!tfile)
1073 goto drop;
1074
1075 if (!rcu_dereference(tun->steering_prog))
1076 tun_automq_xmit(tun, skb);
1077
1078 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
1079
1080 BUG_ON(!tfile);
1081
1082 /* Drop if the filter does not like it.
1083 * This is a noop if the filter is disabled.
1084 * Filter can be enabled only for the TAP devices. */
1085 if (!check_filter(&tun->txflt, skb))
1086 goto drop;
1087
1088 if (tfile->socket.sk->sk_filter &&
1089 sk_filter(tfile->socket.sk, skb))
1090 goto drop;
1091
1092 len = run_ebpf_filter(tun, skb, len);
1093 if (len == 0 || pskb_trim(skb, len))
1094 goto drop;
1095
1096 if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC)))
1097 goto drop;
1098
1099 skb_tx_timestamp(skb);
1100
1101 /* Orphan the skb - required as we might hang on to it
1102 * for indefinite time.
1103 */
1104 skb_orphan(skb);
1105
1106 nf_reset(skb);
1107
1108 if (ptr_ring_produce(&tfile->tx_ring, skb))
1109 goto drop;
1110
1111 /* Notify and wake up reader process */
1112 if (tfile->flags & TUN_FASYNC)
1113 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1114 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1115
1116 rcu_read_unlock();
1117 return NETDEV_TX_OK;
1118
1119 drop:
1120 this_cpu_inc(tun->pcpu_stats->tx_dropped);
1121 skb_tx_error(skb);
1122 kfree_skb(skb);
1123 rcu_read_unlock();
1124 return NET_XMIT_DROP;
1125 }
1126
1127 static void tun_net_mclist(struct net_device *dev)
1128 {
1129 /*
1130 * This callback is supposed to deal with mc filter in
1131 * _rx_ path and has nothing to do with the _tx_ path.
1132 * In rx path we always accept everything userspace gives us.
1133 */
1134 }
1135
1136 static netdev_features_t tun_net_fix_features(struct net_device *dev,
1137 netdev_features_t features)
1138 {
1139 struct tun_struct *tun = netdev_priv(dev);
1140
1141 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
1142 }
1143
1144 static void tun_set_headroom(struct net_device *dev, int new_hr)
1145 {
1146 struct tun_struct *tun = netdev_priv(dev);
1147
1148 if (new_hr < NET_SKB_PAD)
1149 new_hr = NET_SKB_PAD;
1150
1151 tun->align = new_hr;
1152 }
1153
1154 static void
1155 tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
1156 {
1157 u32 rx_dropped = 0, tx_dropped = 0, rx_frame_errors = 0;
1158 struct tun_struct *tun = netdev_priv(dev);
1159 struct tun_pcpu_stats *p;
1160 int i;
1161
1162 for_each_possible_cpu(i) {
1163 u64 rxpackets, rxbytes, txpackets, txbytes;
1164 unsigned int start;
1165
1166 p = per_cpu_ptr(tun->pcpu_stats, i);
1167 do {
1168 start = u64_stats_fetch_begin(&p->syncp);
1169 rxpackets = p->rx_packets;
1170 rxbytes = p->rx_bytes;
1171 txpackets = p->tx_packets;
1172 txbytes = p->tx_bytes;
1173 } while (u64_stats_fetch_retry(&p->syncp, start));
1174
1175 stats->rx_packets += rxpackets;
1176 stats->rx_bytes += rxbytes;
1177 stats->tx_packets += txpackets;
1178 stats->tx_bytes += txbytes;
1179
1180 /* u32 counters */
1181 rx_dropped += p->rx_dropped;
1182 rx_frame_errors += p->rx_frame_errors;
1183 tx_dropped += p->tx_dropped;
1184 }
1185 stats->rx_dropped = rx_dropped;
1186 stats->rx_frame_errors = rx_frame_errors;
1187 stats->tx_dropped = tx_dropped;
1188 }
1189
1190 static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1191 struct netlink_ext_ack *extack)
1192 {
1193 struct tun_struct *tun = netdev_priv(dev);
1194 struct tun_file *tfile;
1195 struct bpf_prog *old_prog;
1196 int i;
1197
1198 old_prog = rtnl_dereference(tun->xdp_prog);
1199 rcu_assign_pointer(tun->xdp_prog, prog);
1200 if (old_prog)
1201 bpf_prog_put(old_prog);
1202
1203 for (i = 0; i < tun->numqueues; i++) {
1204 tfile = rtnl_dereference(tun->tfiles[i]);
1205 if (prog)
1206 sock_set_flag(&tfile->sk, SOCK_XDP);
1207 else
1208 sock_reset_flag(&tfile->sk, SOCK_XDP);
1209 }
1210 list_for_each_entry(tfile, &tun->disabled, next) {
1211 if (prog)
1212 sock_set_flag(&tfile->sk, SOCK_XDP);
1213 else
1214 sock_reset_flag(&tfile->sk, SOCK_XDP);
1215 }
1216
1217 return 0;
1218 }
1219
1220 static u32 tun_xdp_query(struct net_device *dev)
1221 {
1222 struct tun_struct *tun = netdev_priv(dev);
1223 const struct bpf_prog *xdp_prog;
1224
1225 xdp_prog = rtnl_dereference(tun->xdp_prog);
1226 if (xdp_prog)
1227 return xdp_prog->aux->id;
1228
1229 return 0;
1230 }
1231
1232 static int tun_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1233 {
1234 switch (xdp->command) {
1235 case XDP_SETUP_PROG:
1236 return tun_xdp_set(dev, xdp->prog, xdp->extack);
1237 case XDP_QUERY_PROG:
1238 xdp->prog_id = tun_xdp_query(dev);
1239 return 0;
1240 default:
1241 return -EINVAL;
1242 }
1243 }
1244
1245 static int tun_net_change_carrier(struct net_device *dev, bool new_carrier)
1246 {
1247 if (new_carrier) {
1248 struct tun_struct *tun = netdev_priv(dev);
1249
1250 if (!tun->numqueues)
1251 return -EPERM;
1252
1253 netif_carrier_on(dev);
1254 } else {
1255 netif_carrier_off(dev);
1256 }
1257 return 0;
1258 }
1259
1260 static const struct net_device_ops tun_netdev_ops = {
1261 .ndo_uninit = tun_net_uninit,
1262 .ndo_open = tun_net_open,
1263 .ndo_stop = tun_net_close,
1264 .ndo_start_xmit = tun_net_xmit,
1265 .ndo_fix_features = tun_net_fix_features,
1266 .ndo_select_queue = tun_select_queue,
1267 .ndo_set_rx_headroom = tun_set_headroom,
1268 .ndo_get_stats64 = tun_net_get_stats64,
1269 .ndo_change_carrier = tun_net_change_carrier,
1270 };
1271
1272 static void __tun_xdp_flush_tfile(struct tun_file *tfile)
1273 {
1274 /* Notify and wake up reader process */
1275 if (tfile->flags & TUN_FASYNC)
1276 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1277 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1278 }
1279
1280 static int tun_xdp_xmit(struct net_device *dev, int n,
1281 struct xdp_frame **frames, u32 flags)
1282 {
1283 struct tun_struct *tun = netdev_priv(dev);
1284 struct tun_file *tfile;
1285 u32 numqueues;
1286 int drops = 0;
1287 int cnt = n;
1288 int i;
1289
1290 if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
1291 return -EINVAL;
1292
1293 rcu_read_lock();
1294
1295 resample:
1296 numqueues = READ_ONCE(tun->numqueues);
1297 if (!numqueues) {
1298 rcu_read_unlock();
1299 return -ENXIO; /* Caller will free/return all frames */
1300 }
1301
1302 tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
1303 numqueues]);
1304 if (unlikely(!tfile))
1305 goto resample;
1306
1307 spin_lock(&tfile->tx_ring.producer_lock);
1308 for (i = 0; i < n; i++) {
1309 struct xdp_frame *xdp = frames[i];
1310 /* Encode the XDP flag into lowest bit for consumer to differ
1311 * XDP buffer from sk_buff.
1312 */
1313 void *frame = tun_xdp_to_ptr(xdp);
1314
1315 if (__ptr_ring_produce(&tfile->tx_ring, frame)) {
1316 this_cpu_inc(tun->pcpu_stats->tx_dropped);
1317 xdp_return_frame_rx_napi(xdp);
1318 drops++;
1319 }
1320 }
1321 spin_unlock(&tfile->tx_ring.producer_lock);
1322
1323 if (flags & XDP_XMIT_FLUSH)
1324 __tun_xdp_flush_tfile(tfile);
1325
1326 rcu_read_unlock();
1327 return cnt - drops;
1328 }
1329
1330 static int tun_xdp_tx(struct net_device *dev, struct xdp_buff *xdp)
1331 {
1332 struct xdp_frame *frame = convert_to_xdp_frame(xdp);
1333
1334 if (unlikely(!frame))
1335 return -EOVERFLOW;
1336
1337 return tun_xdp_xmit(dev, 1, &frame, XDP_XMIT_FLUSH);
1338 }
1339
1340 static const struct net_device_ops tap_netdev_ops = {
1341 .ndo_uninit = tun_net_uninit,
1342 .ndo_open = tun_net_open,
1343 .ndo_stop = tun_net_close,
1344 .ndo_start_xmit = tun_net_xmit,
1345 .ndo_fix_features = tun_net_fix_features,
1346 .ndo_set_rx_mode = tun_net_mclist,
1347 .ndo_set_mac_address = eth_mac_addr,
1348 .ndo_validate_addr = eth_validate_addr,
1349 .ndo_select_queue = tun_select_queue,
1350 .ndo_features_check = passthru_features_check,
1351 .ndo_set_rx_headroom = tun_set_headroom,
1352 .ndo_get_stats64 = tun_net_get_stats64,
1353 .ndo_bpf = tun_xdp,
1354 .ndo_xdp_xmit = tun_xdp_xmit,
1355 .ndo_change_carrier = tun_net_change_carrier,
1356 };
1357
1358 static void tun_flow_init(struct tun_struct *tun)
1359 {
1360 int i;
1361
1362 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1363 INIT_HLIST_HEAD(&tun->flows[i]);
1364
1365 tun->ageing_time = TUN_FLOW_EXPIRE;
1366 timer_setup(&tun->flow_gc_timer, tun_flow_cleanup, 0);
1367 mod_timer(&tun->flow_gc_timer,
1368 round_jiffies_up(jiffies + tun->ageing_time));
1369 }
1370
1371 static void tun_flow_uninit(struct tun_struct *tun)
1372 {
1373 del_timer_sync(&tun->flow_gc_timer);
1374 tun_flow_flush(tun);
1375 }
1376
1377 #define MIN_MTU 68
1378 #define MAX_MTU 65535
1379
1380 /* Initialize net device. */
1381 static void tun_net_init(struct net_device *dev)
1382 {
1383 struct tun_struct *tun = netdev_priv(dev);
1384
1385 switch (tun->flags & TUN_TYPE_MASK) {
1386 case IFF_TUN:
1387 dev->netdev_ops = &tun_netdev_ops;
1388
1389 /* Point-to-Point TUN Device */
1390 dev->hard_header_len = 0;
1391 dev->addr_len = 0;
1392 dev->mtu = 1500;
1393
1394 /* Zero header length */
1395 dev->type = ARPHRD_NONE;
1396 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1397 break;
1398
1399 case IFF_TAP:
1400 dev->netdev_ops = &tap_netdev_ops;
1401 /* Ethernet TAP Device */
1402 ether_setup(dev);
1403 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1404 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1405
1406 eth_hw_addr_random(dev);
1407
1408 break;
1409 }
1410
1411 dev->min_mtu = MIN_MTU;
1412 dev->max_mtu = MAX_MTU - dev->hard_header_len;
1413 }
1414
1415 static bool tun_sock_writeable(struct tun_struct *tun, struct tun_file *tfile)
1416 {
1417 struct sock *sk = tfile->socket.sk;
1418
1419 return (tun->dev->flags & IFF_UP) && sock_writeable(sk);
1420 }
1421
1422 /* Character device part */
1423
1424 /* Poll */
1425 static __poll_t tun_chr_poll(struct file *file, poll_table *wait)
1426 {
1427 struct tun_file *tfile = file->private_data;
1428 struct tun_struct *tun = tun_get(tfile);
1429 struct sock *sk;
1430 __poll_t mask = 0;
1431
1432 if (!tun)
1433 return EPOLLERR;
1434
1435 sk = tfile->socket.sk;
1436
1437 tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
1438
1439 poll_wait(file, sk_sleep(sk), wait);
1440
1441 if (!ptr_ring_empty(&tfile->tx_ring))
1442 mask |= EPOLLIN | EPOLLRDNORM;
1443
1444 /* Make sure SOCKWQ_ASYNC_NOSPACE is set if not writable to
1445 * guarantee EPOLLOUT to be raised by either here or
1446 * tun_sock_write_space(). Then process could get notification
1447 * after it writes to a down device and meets -EIO.
1448 */
1449 if (tun_sock_writeable(tun, tfile) ||
1450 (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1451 tun_sock_writeable(tun, tfile)))
1452 mask |= EPOLLOUT | EPOLLWRNORM;
1453
1454 if (tun->dev->reg_state != NETREG_REGISTERED)
1455 mask = EPOLLERR;
1456
1457 tun_put(tun);
1458 return mask;
1459 }
1460
1461 static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile,
1462 size_t len,
1463 const struct iov_iter *it)
1464 {
1465 struct sk_buff *skb;
1466 size_t linear;
1467 int err;
1468 int i;
1469
1470 if (it->nr_segs > MAX_SKB_FRAGS + 1)
1471 return ERR_PTR(-ENOMEM);
1472
1473 local_bh_disable();
1474 skb = napi_get_frags(&tfile->napi);
1475 local_bh_enable();
1476 if (!skb)
1477 return ERR_PTR(-ENOMEM);
1478
1479 linear = iov_iter_single_seg_count(it);
1480 err = __skb_grow(skb, linear);
1481 if (err)
1482 goto free;
1483
1484 skb->len = len;
1485 skb->data_len = len - linear;
1486 skb->truesize += skb->data_len;
1487
1488 for (i = 1; i < it->nr_segs; i++) {
1489 size_t fragsz = it->iov[i].iov_len;
1490 struct page *page;
1491 void *frag;
1492
1493 if (fragsz == 0 || fragsz > PAGE_SIZE) {
1494 err = -EINVAL;
1495 goto free;
1496 }
1497 frag = netdev_alloc_frag(fragsz);
1498 if (!frag) {
1499 err = -ENOMEM;
1500 goto free;
1501 }
1502 page = virt_to_head_page(frag);
1503 skb_fill_page_desc(skb, i - 1, page,
1504 frag - page_address(page), fragsz);
1505 }
1506
1507 return skb;
1508 free:
1509 /* frees skb and all frags allocated with napi_alloc_frag() */
1510 napi_free_frags(&tfile->napi);
1511 return ERR_PTR(err);
1512 }
1513
1514 /* prepad is the amount to reserve at front. len is length after that.
1515 * linear is a hint as to how much to copy (usually headers). */
1516 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1517 size_t prepad, size_t len,
1518 size_t linear, int noblock)
1519 {
1520 struct sock *sk = tfile->socket.sk;
1521 struct sk_buff *skb;
1522 int err;
1523
1524 /* Under a page? Don't bother with paged skb. */
1525 if (prepad + len < PAGE_SIZE || !linear)
1526 linear = len;
1527
1528 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1529 &err, 0);
1530 if (!skb)
1531 return ERR_PTR(err);
1532
1533 skb_reserve(skb, prepad);
1534 skb_put(skb, linear);
1535 skb->data_len = len - linear;
1536 skb->len += len - linear;
1537
1538 return skb;
1539 }
1540
1541 static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile,
1542 struct sk_buff *skb, int more)
1543 {
1544 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1545 struct sk_buff_head process_queue;
1546 u32 rx_batched = tun->rx_batched;
1547 bool rcv = false;
1548
1549 if (!rx_batched || (!more && skb_queue_empty(queue))) {
1550 local_bh_disable();
1551 skb_record_rx_queue(skb, tfile->queue_index);
1552 netif_receive_skb(skb);
1553 local_bh_enable();
1554 return;
1555 }
1556
1557 spin_lock(&queue->lock);
1558 if (!more || skb_queue_len(queue) == rx_batched) {
1559 __skb_queue_head_init(&process_queue);
1560 skb_queue_splice_tail_init(queue, &process_queue);
1561 rcv = true;
1562 } else {
1563 __skb_queue_tail(queue, skb);
1564 }
1565 spin_unlock(&queue->lock);
1566
1567 if (rcv) {
1568 struct sk_buff *nskb;
1569
1570 local_bh_disable();
1571 while ((nskb = __skb_dequeue(&process_queue))) {
1572 skb_record_rx_queue(nskb, tfile->queue_index);
1573 netif_receive_skb(nskb);
1574 }
1575 skb_record_rx_queue(skb, tfile->queue_index);
1576 netif_receive_skb(skb);
1577 local_bh_enable();
1578 }
1579 }
1580
1581 static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile,
1582 int len, int noblock, bool zerocopy)
1583 {
1584 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
1585 return false;
1586
1587 if (tfile->socket.sk->sk_sndbuf != INT_MAX)
1588 return false;
1589
1590 if (!noblock)
1591 return false;
1592
1593 if (zerocopy)
1594 return false;
1595
1596 if (SKB_DATA_ALIGN(len + TUN_RX_PAD) +
1597 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
1598 return false;
1599
1600 return true;
1601 }
1602
1603 static struct sk_buff *__tun_build_skb(struct page_frag *alloc_frag, char *buf,
1604 int buflen, int len, int pad)
1605 {
1606 struct sk_buff *skb = build_skb(buf, buflen);
1607
1608 if (!skb)
1609 return ERR_PTR(-ENOMEM);
1610
1611 skb_reserve(skb, pad);
1612 skb_put(skb, len);
1613
1614 get_page(alloc_frag->page);
1615 alloc_frag->offset += buflen;
1616
1617 return skb;
1618 }
1619
1620 static int tun_xdp_act(struct tun_struct *tun, struct bpf_prog *xdp_prog,
1621 struct xdp_buff *xdp, u32 act)
1622 {
1623 int err;
1624
1625 switch (act) {
1626 case XDP_REDIRECT:
1627 err = xdp_do_redirect(tun->dev, xdp, xdp_prog);
1628 if (err)
1629 return err;
1630 break;
1631 case XDP_TX:
1632 err = tun_xdp_tx(tun->dev, xdp);
1633 if (err < 0)
1634 return err;
1635 break;
1636 case XDP_PASS:
1637 break;
1638 default:
1639 bpf_warn_invalid_xdp_action(act);
1640 /* fall through */
1641 case XDP_ABORTED:
1642 trace_xdp_exception(tun->dev, xdp_prog, act);
1643 /* fall through */
1644 case XDP_DROP:
1645 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1646 break;
1647 }
1648
1649 return act;
1650 }
1651
1652 static struct sk_buff *tun_build_skb(struct tun_struct *tun,
1653 struct tun_file *tfile,
1654 struct iov_iter *from,
1655 struct virtio_net_hdr *hdr,
1656 int len, int *skb_xdp)
1657 {
1658 struct page_frag *alloc_frag = &current->task_frag;
1659 struct bpf_prog *xdp_prog;
1660 int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1661 char *buf;
1662 size_t copied;
1663 int pad = TUN_RX_PAD;
1664 int err = 0;
1665
1666 rcu_read_lock();
1667 xdp_prog = rcu_dereference(tun->xdp_prog);
1668 if (xdp_prog)
1669 pad += XDP_PACKET_HEADROOM;
1670 buflen += SKB_DATA_ALIGN(len + pad);
1671 rcu_read_unlock();
1672
1673 alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES);
1674 if (unlikely(!skb_page_frag_refill(buflen, alloc_frag, GFP_KERNEL)))
1675 return ERR_PTR(-ENOMEM);
1676
1677 buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
1678 copied = copy_page_from_iter(alloc_frag->page,
1679 alloc_frag->offset + pad,
1680 len, from);
1681 if (copied != len)
1682 return ERR_PTR(-EFAULT);
1683
1684 /* There's a small window that XDP may be set after the check
1685 * of xdp_prog above, this should be rare and for simplicity
1686 * we do XDP on skb in case the headroom is not enough.
1687 */
1688 if (hdr->gso_type || !xdp_prog) {
1689 *skb_xdp = 1;
1690 return __tun_build_skb(alloc_frag, buf, buflen, len, pad);
1691 }
1692
1693 *skb_xdp = 0;
1694
1695 local_bh_disable();
1696 rcu_read_lock();
1697 xdp_prog = rcu_dereference(tun->xdp_prog);
1698 if (xdp_prog) {
1699 struct xdp_buff xdp;
1700 u32 act;
1701
1702 xdp.data_hard_start = buf;
1703 xdp.data = buf + pad;
1704 xdp_set_data_meta_invalid(&xdp);
1705 xdp.data_end = xdp.data + len;
1706 xdp.rxq = &tfile->xdp_rxq;
1707
1708 act = bpf_prog_run_xdp(xdp_prog, &xdp);
1709 if (act == XDP_REDIRECT || act == XDP_TX) {
1710 get_page(alloc_frag->page);
1711 alloc_frag->offset += buflen;
1712 }
1713 err = tun_xdp_act(tun, xdp_prog, &xdp, act);
1714 if (err < 0)
1715 goto err_xdp;
1716 if (err == XDP_REDIRECT)
1717 xdp_do_flush_map();
1718 if (err != XDP_PASS)
1719 goto out;
1720
1721 pad = xdp.data - xdp.data_hard_start;
1722 len = xdp.data_end - xdp.data;
1723 }
1724 rcu_read_unlock();
1725 local_bh_enable();
1726
1727 return __tun_build_skb(alloc_frag, buf, buflen, len, pad);
1728
1729 err_xdp:
1730 put_page(alloc_frag->page);
1731 out:
1732 rcu_read_unlock();
1733 local_bh_enable();
1734 return NULL;
1735 }
1736
1737 /* Get packet from user space buffer */
1738 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1739 void *msg_control, struct iov_iter *from,
1740 int noblock, bool more)
1741 {
1742 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1743 struct sk_buff *skb;
1744 size_t total_len = iov_iter_count(from);
1745 size_t len = total_len, align = tun->align, linear;
1746 struct virtio_net_hdr gso = { 0 };
1747 struct tun_pcpu_stats *stats;
1748 int good_linear;
1749 int copylen;
1750 bool zerocopy = false;
1751 int err;
1752 u32 rxhash = 0;
1753 int skb_xdp = 1;
1754 bool frags = tun_napi_frags_enabled(tfile);
1755
1756 if (!(tun->flags & IFF_NO_PI)) {
1757 if (len < sizeof(pi))
1758 return -EINVAL;
1759 len -= sizeof(pi);
1760
1761 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1762 return -EFAULT;
1763 }
1764
1765 if (tun->flags & IFF_VNET_HDR) {
1766 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1767
1768 if (len < vnet_hdr_sz)
1769 return -EINVAL;
1770 len -= vnet_hdr_sz;
1771
1772 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1773 return -EFAULT;
1774
1775 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1776 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1777 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1778
1779 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1780 return -EINVAL;
1781 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1782 }
1783
1784 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1785 align += NET_IP_ALIGN;
1786 if (unlikely(len < ETH_HLEN ||
1787 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1788 return -EINVAL;
1789 }
1790
1791 good_linear = SKB_MAX_HEAD(align);
1792
1793 if (msg_control) {
1794 struct iov_iter i = *from;
1795
1796 /* There are 256 bytes to be copied in skb, so there is
1797 * enough room for skb expand head in case it is used.
1798 * The rest of the buffer is mapped from userspace.
1799 */
1800 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1801 if (copylen > good_linear)
1802 copylen = good_linear;
1803 linear = copylen;
1804 iov_iter_advance(&i, copylen);
1805 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1806 zerocopy = true;
1807 }
1808
1809 if (!frags && tun_can_build_skb(tun, tfile, len, noblock, zerocopy)) {
1810 /* For the packet that is not easy to be processed
1811 * (e.g gso or jumbo packet), we will do it at after
1812 * skb was created with generic XDP routine.
1813 */
1814 skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp);
1815 if (IS_ERR(skb)) {
1816 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1817 return PTR_ERR(skb);
1818 }
1819 if (!skb)
1820 return total_len;
1821 } else {
1822 if (!zerocopy) {
1823 copylen = len;
1824 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1825 linear = good_linear;
1826 else
1827 linear = tun16_to_cpu(tun, gso.hdr_len);
1828 }
1829
1830 if (frags) {
1831 mutex_lock(&tfile->napi_mutex);
1832 skb = tun_napi_alloc_frags(tfile, copylen, from);
1833 /* tun_napi_alloc_frags() enforces a layout for the skb.
1834 * If zerocopy is enabled, then this layout will be
1835 * overwritten by zerocopy_sg_from_iter().
1836 */
1837 zerocopy = false;
1838 } else {
1839 skb = tun_alloc_skb(tfile, align, copylen, linear,
1840 noblock);
1841 }
1842
1843 if (IS_ERR(skb)) {
1844 if (PTR_ERR(skb) != -EAGAIN)
1845 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1846 if (frags)
1847 mutex_unlock(&tfile->napi_mutex);
1848 return PTR_ERR(skb);
1849 }
1850
1851 if (zerocopy)
1852 err = zerocopy_sg_from_iter(skb, from);
1853 else
1854 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1855
1856 if (err) {
1857 err = -EFAULT;
1858 drop:
1859 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1860 kfree_skb(skb);
1861 if (frags) {
1862 tfile->napi.skb = NULL;
1863 mutex_unlock(&tfile->napi_mutex);
1864 }
1865
1866 return err;
1867 }
1868 }
1869
1870 if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1871 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
1872 kfree_skb(skb);
1873 if (frags) {
1874 tfile->napi.skb = NULL;
1875 mutex_unlock(&tfile->napi_mutex);
1876 }
1877
1878 return -EINVAL;
1879 }
1880
1881 switch (tun->flags & TUN_TYPE_MASK) {
1882 case IFF_TUN:
1883 if (tun->flags & IFF_NO_PI) {
1884 u8 ip_version = skb->len ? (skb->data[0] >> 4) : 0;
1885
1886 switch (ip_version) {
1887 case 4:
1888 pi.proto = htons(ETH_P_IP);
1889 break;
1890 case 6:
1891 pi.proto = htons(ETH_P_IPV6);
1892 break;
1893 default:
1894 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1895 kfree_skb(skb);
1896 return -EINVAL;
1897 }
1898 }
1899
1900 skb_reset_mac_header(skb);
1901 skb->protocol = pi.proto;
1902 skb->dev = tun->dev;
1903 break;
1904 case IFF_TAP:
1905 if (!frags)
1906 skb->protocol = eth_type_trans(skb, tun->dev);
1907 break;
1908 }
1909
1910 /* copy skb_ubuf_info for callback when skb has no error */
1911 if (zerocopy) {
1912 skb_shinfo(skb)->destructor_arg = msg_control;
1913 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1914 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1915 } else if (msg_control) {
1916 struct ubuf_info *uarg = msg_control;
1917 uarg->callback(uarg, false);
1918 }
1919
1920 skb_reset_network_header(skb);
1921 skb_probe_transport_header(skb);
1922
1923 if (skb_xdp) {
1924 struct bpf_prog *xdp_prog;
1925 int ret;
1926
1927 local_bh_disable();
1928 rcu_read_lock();
1929 xdp_prog = rcu_dereference(tun->xdp_prog);
1930 if (xdp_prog) {
1931 ret = do_xdp_generic(xdp_prog, skb);
1932 if (ret != XDP_PASS) {
1933 rcu_read_unlock();
1934 local_bh_enable();
1935 return total_len;
1936 }
1937 }
1938 rcu_read_unlock();
1939 local_bh_enable();
1940 }
1941
1942 /* Compute the costly rx hash only if needed for flow updates.
1943 * We may get a very small possibility of OOO during switching, not
1944 * worth to optimize.
1945 */
1946 if (!rcu_access_pointer(tun->steering_prog) && tun->numqueues > 1 &&
1947 !tfile->detached)
1948 rxhash = __skb_get_hash_symmetric(skb);
1949
1950 rcu_read_lock();
1951 if (unlikely(!(tun->dev->flags & IFF_UP))) {
1952 err = -EIO;
1953 rcu_read_unlock();
1954 goto drop;
1955 }
1956
1957 if (frags) {
1958 /* Exercise flow dissector code path. */
1959 u32 headlen = eth_get_headlen(tun->dev, skb->data,
1960 skb_headlen(skb));
1961
1962 if (unlikely(headlen > skb_headlen(skb))) {
1963 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1964 napi_free_frags(&tfile->napi);
1965 rcu_read_unlock();
1966 mutex_unlock(&tfile->napi_mutex);
1967 WARN_ON(1);
1968 return -ENOMEM;
1969 }
1970
1971 local_bh_disable();
1972 napi_gro_frags(&tfile->napi);
1973 local_bh_enable();
1974 mutex_unlock(&tfile->napi_mutex);
1975 } else if (tfile->napi_enabled) {
1976 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1977 int queue_len;
1978
1979 spin_lock_bh(&queue->lock);
1980 __skb_queue_tail(queue, skb);
1981 queue_len = skb_queue_len(queue);
1982 spin_unlock(&queue->lock);
1983
1984 if (!more || queue_len > NAPI_POLL_WEIGHT)
1985 napi_schedule(&tfile->napi);
1986
1987 local_bh_enable();
1988 } else if (!IS_ENABLED(CONFIG_4KSTACKS)) {
1989 tun_rx_batched(tun, tfile, skb, more);
1990 } else {
1991 netif_rx_ni(skb);
1992 }
1993 rcu_read_unlock();
1994
1995 stats = get_cpu_ptr(tun->pcpu_stats);
1996 u64_stats_update_begin(&stats->syncp);
1997 stats->rx_packets++;
1998 stats->rx_bytes += len;
1999 u64_stats_update_end(&stats->syncp);
2000 put_cpu_ptr(stats);
2001
2002 if (rxhash)
2003 tun_flow_update(tun, rxhash, tfile);
2004
2005 return total_len;
2006 }
2007
2008 static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
2009 {
2010 struct file *file = iocb->ki_filp;
2011 struct tun_file *tfile = file->private_data;
2012 struct tun_struct *tun = tun_get(tfile);
2013 ssize_t result;
2014
2015 if (!tun)
2016 return -EBADFD;
2017
2018 result = tun_get_user(tun, tfile, NULL, from,
2019 file->f_flags & O_NONBLOCK, false);
2020
2021 tun_put(tun);
2022 return result;
2023 }
2024
2025 static ssize_t tun_put_user_xdp(struct tun_struct *tun,
2026 struct tun_file *tfile,
2027 struct xdp_frame *xdp_frame,
2028 struct iov_iter *iter)
2029 {
2030 int vnet_hdr_sz = 0;
2031 size_t size = xdp_frame->len;
2032 struct tun_pcpu_stats *stats;
2033 size_t ret;
2034
2035 if (tun->flags & IFF_VNET_HDR) {
2036 struct virtio_net_hdr gso = { 0 };
2037
2038 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2039 if (unlikely(iov_iter_count(iter) < vnet_hdr_sz))
2040 return -EINVAL;
2041 if (unlikely(copy_to_iter(&gso, sizeof(gso), iter) !=
2042 sizeof(gso)))
2043 return -EFAULT;
2044 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2045 }
2046
2047 ret = copy_to_iter(xdp_frame->data, size, iter) + vnet_hdr_sz;
2048
2049 stats = get_cpu_ptr(tun->pcpu_stats);
2050 u64_stats_update_begin(&stats->syncp);
2051 stats->tx_packets++;
2052 stats->tx_bytes += ret;
2053 u64_stats_update_end(&stats->syncp);
2054 put_cpu_ptr(tun->pcpu_stats);
2055
2056 return ret;
2057 }
2058
2059 /* Put packet to the user space buffer */
2060 static ssize_t tun_put_user(struct tun_struct *tun,
2061 struct tun_file *tfile,
2062 struct sk_buff *skb,
2063 struct iov_iter *iter)
2064 {
2065 struct tun_pi pi = { 0, skb->protocol };
2066 struct tun_pcpu_stats *stats;
2067 ssize_t total;
2068 int vlan_offset = 0;
2069 int vlan_hlen = 0;
2070 int vnet_hdr_sz = 0;
2071
2072 if (skb_vlan_tag_present(skb))
2073 vlan_hlen = VLAN_HLEN;
2074
2075 if (tun->flags & IFF_VNET_HDR)
2076 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2077
2078 total = skb->len + vlan_hlen + vnet_hdr_sz;
2079
2080 if (!(tun->flags & IFF_NO_PI)) {
2081 if (iov_iter_count(iter) < sizeof(pi))
2082 return -EINVAL;
2083
2084 total += sizeof(pi);
2085 if (iov_iter_count(iter) < total) {
2086 /* Packet will be striped */
2087 pi.flags |= TUN_PKT_STRIP;
2088 }
2089
2090 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
2091 return -EFAULT;
2092 }
2093
2094 if (vnet_hdr_sz) {
2095 struct virtio_net_hdr gso;
2096
2097 if (iov_iter_count(iter) < vnet_hdr_sz)
2098 return -EINVAL;
2099
2100 if (virtio_net_hdr_from_skb(skb, &gso,
2101 tun_is_little_endian(tun), true,
2102 vlan_hlen)) {
2103 struct skb_shared_info *sinfo = skb_shinfo(skb);
2104 pr_err("unexpected GSO type: "
2105 "0x%x, gso_size %d, hdr_len %d\n",
2106 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
2107 tun16_to_cpu(tun, gso.hdr_len));
2108 print_hex_dump(KERN_ERR, "tun: ",
2109 DUMP_PREFIX_NONE,
2110 16, 1, skb->head,
2111 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
2112 WARN_ON_ONCE(1);
2113 return -EINVAL;
2114 }
2115
2116 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
2117 return -EFAULT;
2118
2119 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2120 }
2121
2122 if (vlan_hlen) {
2123 int ret;
2124 struct veth veth;
2125
2126 veth.h_vlan_proto = skb->vlan_proto;
2127 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
2128
2129 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
2130
2131 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
2132 if (ret || !iov_iter_count(iter))
2133 goto done;
2134
2135 ret = copy_to_iter(&veth, sizeof(veth), iter);
2136 if (ret != sizeof(veth) || !iov_iter_count(iter))
2137 goto done;
2138 }
2139
2140 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
2141
2142 done:
2143 /* caller is in process context, */
2144 stats = get_cpu_ptr(tun->pcpu_stats);
2145 u64_stats_update_begin(&stats->syncp);
2146 stats->tx_packets++;
2147 stats->tx_bytes += skb->len + vlan_hlen;
2148 u64_stats_update_end(&stats->syncp);
2149 put_cpu_ptr(tun->pcpu_stats);
2150
2151 return total;
2152 }
2153
2154 static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err)
2155 {
2156 DECLARE_WAITQUEUE(wait, current);
2157 void *ptr = NULL;
2158 int error = 0;
2159
2160 ptr = ptr_ring_consume(&tfile->tx_ring);
2161 if (ptr)
2162 goto out;
2163 if (noblock) {
2164 error = -EAGAIN;
2165 goto out;
2166 }
2167
2168 add_wait_queue(&tfile->wq.wait, &wait);
2169
2170 while (1) {
2171 set_current_state(TASK_INTERRUPTIBLE);
2172 ptr = ptr_ring_consume(&tfile->tx_ring);
2173 if (ptr)
2174 break;
2175 if (signal_pending(current)) {
2176 error = -ERESTARTSYS;
2177 break;
2178 }
2179 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
2180 error = -EFAULT;
2181 break;
2182 }
2183
2184 schedule();
2185 }
2186
2187 __set_current_state(TASK_RUNNING);
2188 remove_wait_queue(&tfile->wq.wait, &wait);
2189
2190 out:
2191 *err = error;
2192 return ptr;
2193 }
2194
2195 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
2196 struct iov_iter *to,
2197 int noblock, void *ptr)
2198 {
2199 ssize_t ret;
2200 int err;
2201
2202 tun_debug(KERN_INFO, tun, "tun_do_read\n");
2203
2204 if (!iov_iter_count(to)) {
2205 tun_ptr_free(ptr);
2206 return 0;
2207 }
2208
2209 if (!ptr) {
2210 /* Read frames from ring */
2211 ptr = tun_ring_recv(tfile, noblock, &err);
2212 if (!ptr)
2213 return err;
2214 }
2215
2216 if (tun_is_xdp_frame(ptr)) {
2217 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2218
2219 ret = tun_put_user_xdp(tun, tfile, xdpf, to);
2220 xdp_return_frame(xdpf);
2221 } else {
2222 struct sk_buff *skb = ptr;
2223
2224 ret = tun_put_user(tun, tfile, skb, to);
2225 if (unlikely(ret < 0))
2226 kfree_skb(skb);
2227 else
2228 consume_skb(skb);
2229 }
2230
2231 return ret;
2232 }
2233
2234 static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
2235 {
2236 struct file *file = iocb->ki_filp;
2237 struct tun_file *tfile = file->private_data;
2238 struct tun_struct *tun = tun_get(tfile);
2239 ssize_t len = iov_iter_count(to), ret;
2240
2241 if (!tun)
2242 return -EBADFD;
2243 ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK, NULL);
2244 ret = min_t(ssize_t, ret, len);
2245 if (ret > 0)
2246 iocb->ki_pos = ret;
2247 tun_put(tun);
2248 return ret;
2249 }
2250
2251 static void tun_prog_free(struct rcu_head *rcu)
2252 {
2253 struct tun_prog *prog = container_of(rcu, struct tun_prog, rcu);
2254
2255 bpf_prog_destroy(prog->prog);
2256 kfree(prog);
2257 }
2258
2259 static int __tun_set_ebpf(struct tun_struct *tun,
2260 struct tun_prog __rcu **prog_p,
2261 struct bpf_prog *prog)
2262 {
2263 struct tun_prog *old, *new = NULL;
2264
2265 if (prog) {
2266 new = kmalloc(sizeof(*new), GFP_KERNEL);
2267 if (!new)
2268 return -ENOMEM;
2269 new->prog = prog;
2270 }
2271
2272 spin_lock_bh(&tun->lock);
2273 old = rcu_dereference_protected(*prog_p,
2274 lockdep_is_held(&tun->lock));
2275 rcu_assign_pointer(*prog_p, new);
2276 spin_unlock_bh(&tun->lock);
2277
2278 if (old)
2279 call_rcu(&old->rcu, tun_prog_free);
2280
2281 return 0;
2282 }
2283
2284 static void tun_free_netdev(struct net_device *dev)
2285 {
2286 struct tun_struct *tun = netdev_priv(dev);
2287
2288 BUG_ON(!(list_empty(&tun->disabled)));
2289 free_percpu(tun->pcpu_stats);
2290 tun_flow_uninit(tun);
2291 security_tun_dev_free_security(tun->security);
2292 __tun_set_ebpf(tun, &tun->steering_prog, NULL);
2293 __tun_set_ebpf(tun, &tun->filter_prog, NULL);
2294 }
2295
2296 static void tun_setup(struct net_device *dev)
2297 {
2298 struct tun_struct *tun = netdev_priv(dev);
2299
2300 tun->owner = INVALID_UID;
2301 tun->group = INVALID_GID;
2302 tun_default_link_ksettings(dev, &tun->link_ksettings);
2303
2304 dev->ethtool_ops = &tun_ethtool_ops;
2305 dev->needs_free_netdev = true;
2306 dev->priv_destructor = tun_free_netdev;
2307 /* We prefer our own queue length */
2308 dev->tx_queue_len = TUN_READQ_SIZE;
2309 }
2310
2311 /* Trivial set of netlink ops to allow deleting tun or tap
2312 * device with netlink.
2313 */
2314 static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
2315 struct netlink_ext_ack *extack)
2316 {
2317 NL_SET_ERR_MSG(extack,
2318 "tun/tap creation via rtnetlink is not supported.");
2319 return -EOPNOTSUPP;
2320 }
2321
2322 static size_t tun_get_size(const struct net_device *dev)
2323 {
2324 BUILD_BUG_ON(sizeof(u32) != sizeof(uid_t));
2325 BUILD_BUG_ON(sizeof(u32) != sizeof(gid_t));
2326
2327 return nla_total_size(sizeof(uid_t)) + /* OWNER */
2328 nla_total_size(sizeof(gid_t)) + /* GROUP */
2329 nla_total_size(sizeof(u8)) + /* TYPE */
2330 nla_total_size(sizeof(u8)) + /* PI */
2331 nla_total_size(sizeof(u8)) + /* VNET_HDR */
2332 nla_total_size(sizeof(u8)) + /* PERSIST */
2333 nla_total_size(sizeof(u8)) + /* MULTI_QUEUE */
2334 nla_total_size(sizeof(u32)) + /* NUM_QUEUES */
2335 nla_total_size(sizeof(u32)) + /* NUM_DISABLED_QUEUES */
2336 0;
2337 }
2338
2339 static int tun_fill_info(struct sk_buff *skb, const struct net_device *dev)
2340 {
2341 struct tun_struct *tun = netdev_priv(dev);
2342
2343 if (nla_put_u8(skb, IFLA_TUN_TYPE, tun->flags & TUN_TYPE_MASK))
2344 goto nla_put_failure;
2345 if (uid_valid(tun->owner) &&
2346 nla_put_u32(skb, IFLA_TUN_OWNER,
2347 from_kuid_munged(current_user_ns(), tun->owner)))
2348 goto nla_put_failure;
2349 if (gid_valid(tun->group) &&
2350 nla_put_u32(skb, IFLA_TUN_GROUP,
2351 from_kgid_munged(current_user_ns(), tun->group)))
2352 goto nla_put_failure;
2353 if (nla_put_u8(skb, IFLA_TUN_PI, !(tun->flags & IFF_NO_PI)))
2354 goto nla_put_failure;
2355 if (nla_put_u8(skb, IFLA_TUN_VNET_HDR, !!(tun->flags & IFF_VNET_HDR)))
2356 goto nla_put_failure;
2357 if (nla_put_u8(skb, IFLA_TUN_PERSIST, !!(tun->flags & IFF_PERSIST)))
2358 goto nla_put_failure;
2359 if (nla_put_u8(skb, IFLA_TUN_MULTI_QUEUE,
2360 !!(tun->flags & IFF_MULTI_QUEUE)))
2361 goto nla_put_failure;
2362 if (tun->flags & IFF_MULTI_QUEUE) {
2363 if (nla_put_u32(skb, IFLA_TUN_NUM_QUEUES, tun->numqueues))
2364 goto nla_put_failure;
2365 if (nla_put_u32(skb, IFLA_TUN_NUM_DISABLED_QUEUES,
2366 tun->numdisabled))
2367 goto nla_put_failure;
2368 }
2369
2370 return 0;
2371
2372 nla_put_failure:
2373 return -EMSGSIZE;
2374 }
2375
2376 static struct rtnl_link_ops tun_link_ops __read_mostly = {
2377 .kind = DRV_NAME,
2378 .priv_size = sizeof(struct tun_struct),
2379 .setup = tun_setup,
2380 .validate = tun_validate,
2381 .get_size = tun_get_size,
2382 .fill_info = tun_fill_info,
2383 };
2384
2385 static void tun_sock_write_space(struct sock *sk)
2386 {
2387 struct tun_file *tfile;
2388 wait_queue_head_t *wqueue;
2389
2390 if (!sock_writeable(sk))
2391 return;
2392
2393 if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
2394 return;
2395
2396 wqueue = sk_sleep(sk);
2397 if (wqueue && waitqueue_active(wqueue))
2398 wake_up_interruptible_sync_poll(wqueue, EPOLLOUT |
2399 EPOLLWRNORM | EPOLLWRBAND);
2400
2401 tfile = container_of(sk, struct tun_file, sk);
2402 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
2403 }
2404
2405 static void tun_put_page(struct tun_page *tpage)
2406 {
2407 if (tpage->page)
2408 __page_frag_cache_drain(tpage->page, tpage->count);
2409 }
2410
2411 static int tun_xdp_one(struct tun_struct *tun,
2412 struct tun_file *tfile,
2413 struct xdp_buff *xdp, int *flush,
2414 struct tun_page *tpage)
2415 {
2416 unsigned int datasize = xdp->data_end - xdp->data;
2417 struct tun_xdp_hdr *hdr = xdp->data_hard_start;
2418 struct virtio_net_hdr *gso = &hdr->gso;
2419 struct tun_pcpu_stats *stats;
2420 struct bpf_prog *xdp_prog;
2421 struct sk_buff *skb = NULL;
2422 u32 rxhash = 0, act;
2423 int buflen = hdr->buflen;
2424 int err = 0;
2425 bool skb_xdp = false;
2426 struct page *page;
2427
2428 xdp_prog = rcu_dereference(tun->xdp_prog);
2429 if (xdp_prog) {
2430 if (gso->gso_type) {
2431 skb_xdp = true;
2432 goto build;
2433 }
2434 xdp_set_data_meta_invalid(xdp);
2435 xdp->rxq = &tfile->xdp_rxq;
2436
2437 act = bpf_prog_run_xdp(xdp_prog, xdp);
2438 err = tun_xdp_act(tun, xdp_prog, xdp, act);
2439 if (err < 0) {
2440 put_page(virt_to_head_page(xdp->data));
2441 return err;
2442 }
2443
2444 switch (err) {
2445 case XDP_REDIRECT:
2446 *flush = true;
2447 /* fall through */
2448 case XDP_TX:
2449 return 0;
2450 case XDP_PASS:
2451 break;
2452 default:
2453 page = virt_to_head_page(xdp->data);
2454 if (tpage->page == page) {
2455 ++tpage->count;
2456 } else {
2457 tun_put_page(tpage);
2458 tpage->page = page;
2459 tpage->count = 1;
2460 }
2461 return 0;
2462 }
2463 }
2464
2465 build:
2466 skb = build_skb(xdp->data_hard_start, buflen);
2467 if (!skb) {
2468 err = -ENOMEM;
2469 goto out;
2470 }
2471
2472 skb_reserve(skb, xdp->data - xdp->data_hard_start);
2473 skb_put(skb, xdp->data_end - xdp->data);
2474
2475 if (virtio_net_hdr_to_skb(skb, gso, tun_is_little_endian(tun))) {
2476 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
2477 kfree_skb(skb);
2478 err = -EINVAL;
2479 goto out;
2480 }
2481
2482 skb->protocol = eth_type_trans(skb, tun->dev);
2483 skb_reset_network_header(skb);
2484 skb_probe_transport_header(skb);
2485
2486 if (skb_xdp) {
2487 err = do_xdp_generic(xdp_prog, skb);
2488 if (err != XDP_PASS)
2489 goto out;
2490 }
2491
2492 if (!rcu_dereference(tun->steering_prog) && tun->numqueues > 1 &&
2493 !tfile->detached)
2494 rxhash = __skb_get_hash_symmetric(skb);
2495
2496 skb_record_rx_queue(skb, tfile->queue_index);
2497 netif_receive_skb(skb);
2498
2499 /* No need for get_cpu_ptr() here since this function is
2500 * always called with bh disabled
2501 */
2502 stats = this_cpu_ptr(tun->pcpu_stats);
2503 u64_stats_update_begin(&stats->syncp);
2504 stats->rx_packets++;
2505 stats->rx_bytes += datasize;
2506 u64_stats_update_end(&stats->syncp);
2507
2508 if (rxhash)
2509 tun_flow_update(tun, rxhash, tfile);
2510
2511 out:
2512 return err;
2513 }
2514
2515 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
2516 {
2517 int ret, i;
2518 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2519 struct tun_struct *tun = tun_get(tfile);
2520 struct tun_msg_ctl *ctl = m->msg_control;
2521 struct xdp_buff *xdp;
2522
2523 if (!tun)
2524 return -EBADFD;
2525
2526 if (ctl && (ctl->type == TUN_MSG_PTR)) {
2527 struct tun_page tpage;
2528 int n = ctl->num;
2529 int flush = 0;
2530
2531 memset(&tpage, 0, sizeof(tpage));
2532
2533 local_bh_disable();
2534 rcu_read_lock();
2535
2536 for (i = 0; i < n; i++) {
2537 xdp = &((struct xdp_buff *)ctl->ptr)[i];
2538 tun_xdp_one(tun, tfile, xdp, &flush, &tpage);
2539 }
2540
2541 if (flush)
2542 xdp_do_flush_map();
2543
2544 rcu_read_unlock();
2545 local_bh_enable();
2546
2547 tun_put_page(&tpage);
2548
2549 ret = total_len;
2550 goto out;
2551 }
2552
2553 ret = tun_get_user(tun, tfile, ctl ? ctl->ptr : NULL, &m->msg_iter,
2554 m->msg_flags & MSG_DONTWAIT,
2555 m->msg_flags & MSG_MORE);
2556 out:
2557 tun_put(tun);
2558 return ret;
2559 }
2560
2561 static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
2562 int flags)
2563 {
2564 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2565 struct tun_struct *tun = tun_get(tfile);
2566 void *ptr = m->msg_control;
2567 int ret;
2568
2569 if (!tun) {
2570 ret = -EBADFD;
2571 goto out_free;
2572 }
2573
2574 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
2575 ret = -EINVAL;
2576 goto out_put_tun;
2577 }
2578 if (flags & MSG_ERRQUEUE) {
2579 ret = sock_recv_errqueue(sock->sk, m, total_len,
2580 SOL_PACKET, TUN_TX_TIMESTAMP);
2581 goto out;
2582 }
2583 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT, ptr);
2584 if (ret > (ssize_t)total_len) {
2585 m->msg_flags |= MSG_TRUNC;
2586 ret = flags & MSG_TRUNC ? ret : total_len;
2587 }
2588 out:
2589 tun_put(tun);
2590 return ret;
2591
2592 out_put_tun:
2593 tun_put(tun);
2594 out_free:
2595 tun_ptr_free(ptr);
2596 return ret;
2597 }
2598
2599 static int tun_ptr_peek_len(void *ptr)
2600 {
2601 if (likely(ptr)) {
2602 if (tun_is_xdp_frame(ptr)) {
2603 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2604
2605 return xdpf->len;
2606 }
2607 return __skb_array_len_with_tag(ptr);
2608 } else {
2609 return 0;
2610 }
2611 }
2612
2613 static int tun_peek_len(struct socket *sock)
2614 {
2615 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2616 struct tun_struct *tun;
2617 int ret = 0;
2618
2619 tun = tun_get(tfile);
2620 if (!tun)
2621 return 0;
2622
2623 ret = PTR_RING_PEEK_CALL(&tfile->tx_ring, tun_ptr_peek_len);
2624 tun_put(tun);
2625
2626 return ret;
2627 }
2628
2629 /* Ops structure to mimic raw sockets with tun */
2630 static const struct proto_ops tun_socket_ops = {
2631 .peek_len = tun_peek_len,
2632 .sendmsg = tun_sendmsg,
2633 .recvmsg = tun_recvmsg,
2634 };
2635
2636 static struct proto tun_proto = {
2637 .name = "tun",
2638 .owner = THIS_MODULE,
2639 .obj_size = sizeof(struct tun_file),
2640 };
2641
2642 static int tun_flags(struct tun_struct *tun)
2643 {
2644 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
2645 }
2646
2647 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
2648 char *buf)
2649 {
2650 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2651 return sprintf(buf, "0x%x\n", tun_flags(tun));
2652 }
2653
2654 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
2655 char *buf)
2656 {
2657 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2658 return uid_valid(tun->owner)?
2659 sprintf(buf, "%u\n",
2660 from_kuid_munged(current_user_ns(), tun->owner)):
2661 sprintf(buf, "-1\n");
2662 }
2663
2664 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
2665 char *buf)
2666 {
2667 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2668 return gid_valid(tun->group) ?
2669 sprintf(buf, "%u\n",
2670 from_kgid_munged(current_user_ns(), tun->group)):
2671 sprintf(buf, "-1\n");
2672 }
2673
2674 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
2675 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
2676 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
2677
2678 static struct attribute *tun_dev_attrs[] = {
2679 &dev_attr_tun_flags.attr,
2680 &dev_attr_owner.attr,
2681 &dev_attr_group.attr,
2682 NULL
2683 };
2684
2685 static const struct attribute_group tun_attr_group = {
2686 .attrs = tun_dev_attrs
2687 };
2688
2689 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
2690 {
2691 struct tun_struct *tun;
2692 struct tun_file *tfile = file->private_data;
2693 struct net_device *dev;
2694 int err;
2695
2696 if (tfile->detached)
2697 return -EINVAL;
2698
2699 if ((ifr->ifr_flags & IFF_NAPI_FRAGS)) {
2700 if (!capable(CAP_NET_ADMIN))
2701 return -EPERM;
2702
2703 if (!(ifr->ifr_flags & IFF_NAPI) ||
2704 (ifr->ifr_flags & TUN_TYPE_MASK) != IFF_TAP)
2705 return -EINVAL;
2706 }
2707
2708 dev = __dev_get_by_name(net, ifr->ifr_name);
2709 if (dev) {
2710 if (ifr->ifr_flags & IFF_TUN_EXCL)
2711 return -EBUSY;
2712 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
2713 tun = netdev_priv(dev);
2714 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
2715 tun = netdev_priv(dev);
2716 else
2717 return -EINVAL;
2718
2719 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
2720 !!(tun->flags & IFF_MULTI_QUEUE))
2721 return -EINVAL;
2722
2723 if (tun_not_capable(tun))
2724 return -EPERM;
2725 err = security_tun_dev_open(tun->security);
2726 if (err < 0)
2727 return err;
2728
2729 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER,
2730 ifr->ifr_flags & IFF_NAPI,
2731 ifr->ifr_flags & IFF_NAPI_FRAGS);
2732 if (err < 0)
2733 return err;
2734
2735 if (tun->flags & IFF_MULTI_QUEUE &&
2736 (tun->numqueues + tun->numdisabled > 1)) {
2737 /* One or more queue has already been attached, no need
2738 * to initialize the device again.
2739 */
2740 netdev_state_change(dev);
2741 return 0;
2742 }
2743
2744 tun->flags = (tun->flags & ~TUN_FEATURES) |
2745 (ifr->ifr_flags & TUN_FEATURES);
2746
2747 netdev_state_change(dev);
2748 } else {
2749 char *name;
2750 unsigned long flags = 0;
2751 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
2752 MAX_TAP_QUEUES : 1;
2753
2754 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2755 return -EPERM;
2756 err = security_tun_dev_create();
2757 if (err < 0)
2758 return err;
2759
2760 /* Set dev type */
2761 if (ifr->ifr_flags & IFF_TUN) {
2762 /* TUN device */
2763 flags |= IFF_TUN;
2764 name = "tun%d";
2765 } else if (ifr->ifr_flags & IFF_TAP) {
2766 /* TAP device */
2767 flags |= IFF_TAP;
2768 name = "tap%d";
2769 } else
2770 return -EINVAL;
2771
2772 if (*ifr->ifr_name)
2773 name = ifr->ifr_name;
2774
2775 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
2776 NET_NAME_UNKNOWN, tun_setup, queues,
2777 queues);
2778
2779 if (!dev)
2780 return -ENOMEM;
2781 err = dev_get_valid_name(net, dev, name);
2782 if (err < 0)
2783 goto err_free_dev;
2784
2785 dev_net_set(dev, net);
2786 dev->rtnl_link_ops = &tun_link_ops;
2787 dev->ifindex = tfile->ifindex;
2788 dev->sysfs_groups[0] = &tun_attr_group;
2789
2790 tun = netdev_priv(dev);
2791 tun->dev = dev;
2792 tun->flags = flags;
2793 tun->txflt.count = 0;
2794 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
2795
2796 tun->align = NET_SKB_PAD;
2797 tun->filter_attached = false;
2798 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
2799 tun->rx_batched = 0;
2800 RCU_INIT_POINTER(tun->steering_prog, NULL);
2801
2802 tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats);
2803 if (!tun->pcpu_stats) {
2804 err = -ENOMEM;
2805 goto err_free_dev;
2806 }
2807
2808 spin_lock_init(&tun->lock);
2809
2810 err = security_tun_dev_alloc_security(&tun->security);
2811 if (err < 0)
2812 goto err_free_stat;
2813
2814 tun_net_init(dev);
2815 tun_flow_init(tun);
2816
2817 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
2818 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
2819 NETIF_F_HW_VLAN_STAG_TX;
2820 dev->features = dev->hw_features | NETIF_F_LLTX;
2821 dev->vlan_features = dev->features &
2822 ~(NETIF_F_HW_VLAN_CTAG_TX |
2823 NETIF_F_HW_VLAN_STAG_TX);
2824
2825 tun->flags = (tun->flags & ~TUN_FEATURES) |
2826 (ifr->ifr_flags & TUN_FEATURES);
2827
2828 INIT_LIST_HEAD(&tun->disabled);
2829 err = tun_attach(tun, file, false, ifr->ifr_flags & IFF_NAPI,
2830 ifr->ifr_flags & IFF_NAPI_FRAGS);
2831 if (err < 0)
2832 goto err_free_flow;
2833
2834 err = register_netdevice(tun->dev);
2835 if (err < 0)
2836 goto err_detach;
2837 }
2838
2839 netif_carrier_on(tun->dev);
2840
2841 tun_debug(KERN_INFO, tun, "tun_set_iff\n");
2842
2843 /* Make sure persistent devices do not get stuck in
2844 * xoff state.
2845 */
2846 if (netif_running(tun->dev))
2847 netif_tx_wake_all_queues(tun->dev);
2848
2849 strcpy(ifr->ifr_name, tun->dev->name);
2850 return 0;
2851
2852 err_detach:
2853 tun_detach_all(dev);
2854 /* register_netdevice() already called tun_free_netdev() */
2855 goto err_free_dev;
2856
2857 err_free_flow:
2858 tun_flow_uninit(tun);
2859 security_tun_dev_free_security(tun->security);
2860 err_free_stat:
2861 free_percpu(tun->pcpu_stats);
2862 err_free_dev:
2863 free_netdev(dev);
2864 return err;
2865 }
2866
2867 static void tun_get_iff(struct tun_struct *tun, struct ifreq *ifr)
2868 {
2869 tun_debug(KERN_INFO, tun, "tun_get_iff\n");
2870
2871 strcpy(ifr->ifr_name, tun->dev->name);
2872
2873 ifr->ifr_flags = tun_flags(tun);
2874
2875 }
2876
2877 /* This is like a cut-down ethtool ops, except done via tun fd so no
2878 * privs required. */
2879 static int set_offload(struct tun_struct *tun, unsigned long arg)
2880 {
2881 netdev_features_t features = 0;
2882
2883 if (arg & TUN_F_CSUM) {
2884 features |= NETIF_F_HW_CSUM;
2885 arg &= ~TUN_F_CSUM;
2886
2887 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
2888 if (arg & TUN_F_TSO_ECN) {
2889 features |= NETIF_F_TSO_ECN;
2890 arg &= ~TUN_F_TSO_ECN;
2891 }
2892 if (arg & TUN_F_TSO4)
2893 features |= NETIF_F_TSO;
2894 if (arg & TUN_F_TSO6)
2895 features |= NETIF_F_TSO6;
2896 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
2897 }
2898
2899 arg &= ~TUN_F_UFO;
2900 }
2901
2902 /* This gives the user a way to test for new features in future by
2903 * trying to set them. */
2904 if (arg)
2905 return -EINVAL;
2906
2907 tun->set_features = features;
2908 tun->dev->wanted_features &= ~TUN_USER_FEATURES;
2909 tun->dev->wanted_features |= features;
2910 netdev_update_features(tun->dev);
2911
2912 return 0;
2913 }
2914
2915 static void tun_detach_filter(struct tun_struct *tun, int n)
2916 {
2917 int i;
2918 struct tun_file *tfile;
2919
2920 for (i = 0; i < n; i++) {
2921 tfile = rtnl_dereference(tun->tfiles[i]);
2922 lock_sock(tfile->socket.sk);
2923 sk_detach_filter(tfile->socket.sk);
2924 release_sock(tfile->socket.sk);
2925 }
2926
2927 tun->filter_attached = false;
2928 }
2929
2930 static int tun_attach_filter(struct tun_struct *tun)
2931 {
2932 int i, ret = 0;
2933 struct tun_file *tfile;
2934
2935 for (i = 0; i < tun->numqueues; i++) {
2936 tfile = rtnl_dereference(tun->tfiles[i]);
2937 lock_sock(tfile->socket.sk);
2938 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
2939 release_sock(tfile->socket.sk);
2940 if (ret) {
2941 tun_detach_filter(tun, i);
2942 return ret;
2943 }
2944 }
2945
2946 tun->filter_attached = true;
2947 return ret;
2948 }
2949
2950 static void tun_set_sndbuf(struct tun_struct *tun)
2951 {
2952 struct tun_file *tfile;
2953 int i;
2954
2955 for (i = 0; i < tun->numqueues; i++) {
2956 tfile = rtnl_dereference(tun->tfiles[i]);
2957 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
2958 }
2959 }
2960
2961 static int tun_set_queue(struct file *file, struct ifreq *ifr)
2962 {
2963 struct tun_file *tfile = file->private_data;
2964 struct tun_struct *tun;
2965 int ret = 0;
2966
2967 rtnl_lock();
2968
2969 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
2970 tun = tfile->detached;
2971 if (!tun) {
2972 ret = -EINVAL;
2973 goto unlock;
2974 }
2975 ret = security_tun_dev_attach_queue(tun->security);
2976 if (ret < 0)
2977 goto unlock;
2978 ret = tun_attach(tun, file, false, tun->flags & IFF_NAPI,
2979 tun->flags & IFF_NAPI_FRAGS);
2980 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
2981 tun = rtnl_dereference(tfile->tun);
2982 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
2983 ret = -EINVAL;
2984 else
2985 __tun_detach(tfile, false);
2986 } else
2987 ret = -EINVAL;
2988
2989 if (ret >= 0)
2990 netdev_state_change(tun->dev);
2991
2992 unlock:
2993 rtnl_unlock();
2994 return ret;
2995 }
2996
2997 static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog **prog_p,
2998 void __user *data)
2999 {
3000 struct bpf_prog *prog;
3001 int fd;
3002
3003 if (copy_from_user(&fd, data, sizeof(fd)))
3004 return -EFAULT;
3005
3006 if (fd == -1) {
3007 prog = NULL;
3008 } else {
3009 prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
3010 if (IS_ERR(prog))
3011 return PTR_ERR(prog);
3012 }
3013
3014 return __tun_set_ebpf(tun, prog_p, prog);
3015 }
3016
3017 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
3018 unsigned long arg, int ifreq_len)
3019 {
3020 struct tun_file *tfile = file->private_data;
3021 struct net *net = sock_net(&tfile->sk);
3022 struct tun_struct *tun;
3023 void __user* argp = (void __user*)arg;
3024 unsigned int ifindex, carrier;
3025 struct ifreq ifr;
3026 kuid_t owner;
3027 kgid_t group;
3028 int sndbuf;
3029 int vnet_hdr_sz;
3030 int le;
3031 int ret;
3032 bool do_notify = false;
3033
3034 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE ||
3035 (_IOC_TYPE(cmd) == SOCK_IOC_TYPE && cmd != SIOCGSKNS)) {
3036 if (copy_from_user(&ifr, argp, ifreq_len))
3037 return -EFAULT;
3038 } else {
3039 memset(&ifr, 0, sizeof(ifr));
3040 }
3041 if (cmd == TUNGETFEATURES) {
3042 /* Currently this just means: "what IFF flags are valid?".
3043 * This is needed because we never checked for invalid flags on
3044 * TUNSETIFF.
3045 */
3046 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
3047 (unsigned int __user*)argp);
3048 } else if (cmd == TUNSETQUEUE) {
3049 return tun_set_queue(file, &ifr);
3050 } else if (cmd == SIOCGSKNS) {
3051 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3052 return -EPERM;
3053 return open_related_ns(&net->ns, get_net_ns);
3054 }
3055
3056 ret = 0;
3057 rtnl_lock();
3058
3059 tun = tun_get(tfile);
3060 if (cmd == TUNSETIFF) {
3061 ret = -EEXIST;
3062 if (tun)
3063 goto unlock;
3064
3065 ifr.ifr_name[IFNAMSIZ-1] = '\0';
3066
3067 ret = tun_set_iff(net, file, &ifr);
3068
3069 if (ret)
3070 goto unlock;
3071
3072 if (copy_to_user(argp, &ifr, ifreq_len))
3073 ret = -EFAULT;
3074 goto unlock;
3075 }
3076 if (cmd == TUNSETIFINDEX) {
3077 ret = -EPERM;
3078 if (tun)
3079 goto unlock;
3080
3081 ret = -EFAULT;
3082 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
3083 goto unlock;
3084
3085 ret = 0;
3086 tfile->ifindex = ifindex;
3087 goto unlock;
3088 }
3089
3090 ret = -EBADFD;
3091 if (!tun)
3092 goto unlock;
3093
3094 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
3095
3096 net = dev_net(tun->dev);
3097 ret = 0;
3098 switch (cmd) {
3099 case TUNGETIFF:
3100 tun_get_iff(tun, &ifr);
3101
3102 if (tfile->detached)
3103 ifr.ifr_flags |= IFF_DETACH_QUEUE;
3104 if (!tfile->socket.sk->sk_filter)
3105 ifr.ifr_flags |= IFF_NOFILTER;
3106
3107 if (copy_to_user(argp, &ifr, ifreq_len))
3108 ret = -EFAULT;
3109 break;
3110
3111 case TUNSETNOCSUM:
3112 /* Disable/Enable checksum */
3113
3114 /* [unimplemented] */
3115 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
3116 arg ? "disabled" : "enabled");
3117 break;
3118
3119 case TUNSETPERSIST:
3120 /* Disable/Enable persist mode. Keep an extra reference to the
3121 * module to prevent the module being unprobed.
3122 */
3123 if (arg && !(tun->flags & IFF_PERSIST)) {
3124 tun->flags |= IFF_PERSIST;
3125 __module_get(THIS_MODULE);
3126 do_notify = true;
3127 }
3128 if (!arg && (tun->flags & IFF_PERSIST)) {
3129 tun->flags &= ~IFF_PERSIST;
3130 module_put(THIS_MODULE);
3131 do_notify = true;
3132 }
3133
3134 tun_debug(KERN_INFO, tun, "persist %s\n",
3135 arg ? "enabled" : "disabled");
3136 break;
3137
3138 case TUNSETOWNER:
3139 /* Set owner of the device */
3140 owner = make_kuid(current_user_ns(), arg);
3141 if (!uid_valid(owner)) {
3142 ret = -EINVAL;
3143 break;
3144 }
3145 tun->owner = owner;
3146 do_notify = true;
3147 tun_debug(KERN_INFO, tun, "owner set to %u\n",
3148 from_kuid(&init_user_ns, tun->owner));
3149 break;
3150
3151 case TUNSETGROUP:
3152 /* Set group of the device */
3153 group = make_kgid(current_user_ns(), arg);
3154 if (!gid_valid(group)) {
3155 ret = -EINVAL;
3156 break;
3157 }
3158 tun->group = group;
3159 do_notify = true;
3160 tun_debug(KERN_INFO, tun, "group set to %u\n",
3161 from_kgid(&init_user_ns, tun->group));
3162 break;
3163
3164 case TUNSETLINK:
3165 /* Only allow setting the type when the interface is down */
3166 if (tun->dev->flags & IFF_UP) {
3167 tun_debug(KERN_INFO, tun,
3168 "Linktype set failed because interface is up\n");
3169 ret = -EBUSY;
3170 } else {
3171 tun->dev->type = (int) arg;
3172 tun_debug(KERN_INFO, tun, "linktype set to %d\n",
3173 tun->dev->type);
3174 ret = 0;
3175 }
3176 break;
3177
3178 #ifdef TUN_DEBUG
3179 case TUNSETDEBUG:
3180 tun->debug = arg;
3181 break;
3182 #endif
3183 case TUNSETOFFLOAD:
3184 ret = set_offload(tun, arg);
3185 break;
3186
3187 case TUNSETTXFILTER:
3188 /* Can be set only for TAPs */
3189 ret = -EINVAL;
3190 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3191 break;
3192 ret = update_filter(&tun->txflt, (void __user *)arg);
3193 break;
3194
3195 case SIOCGIFHWADDR:
3196 /* Get hw address */
3197 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
3198 ifr.ifr_hwaddr.sa_family = tun->dev->type;
3199 if (copy_to_user(argp, &ifr, ifreq_len))
3200 ret = -EFAULT;
3201 break;
3202
3203 case SIOCSIFHWADDR:
3204 /* Set hw address */
3205 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
3206 ifr.ifr_hwaddr.sa_data);
3207
3208 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr, NULL);
3209 break;
3210
3211 case TUNGETSNDBUF:
3212 sndbuf = tfile->socket.sk->sk_sndbuf;
3213 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
3214 ret = -EFAULT;
3215 break;
3216
3217 case TUNSETSNDBUF:
3218 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
3219 ret = -EFAULT;
3220 break;
3221 }
3222 if (sndbuf <= 0) {
3223 ret = -EINVAL;
3224 break;
3225 }
3226
3227 tun->sndbuf = sndbuf;
3228 tun_set_sndbuf(tun);
3229 break;
3230
3231 case TUNGETVNETHDRSZ:
3232 vnet_hdr_sz = tun->vnet_hdr_sz;
3233 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
3234 ret = -EFAULT;
3235 break;
3236
3237 case TUNSETVNETHDRSZ:
3238 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
3239 ret = -EFAULT;
3240 break;
3241 }
3242 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
3243 ret = -EINVAL;
3244 break;
3245 }
3246
3247 tun->vnet_hdr_sz = vnet_hdr_sz;
3248 break;
3249
3250 case TUNGETVNETLE:
3251 le = !!(tun->flags & TUN_VNET_LE);
3252 if (put_user(le, (int __user *)argp))
3253 ret = -EFAULT;
3254 break;
3255
3256 case TUNSETVNETLE:
3257 if (get_user(le, (int __user *)argp)) {
3258 ret = -EFAULT;
3259 break;
3260 }
3261 if (le)
3262 tun->flags |= TUN_VNET_LE;
3263 else
3264 tun->flags &= ~TUN_VNET_LE;
3265 break;
3266
3267 case TUNGETVNETBE:
3268 ret = tun_get_vnet_be(tun, argp);
3269 break;
3270
3271 case TUNSETVNETBE:
3272 ret = tun_set_vnet_be(tun, argp);
3273 break;
3274
3275 case TUNATTACHFILTER:
3276 /* Can be set only for TAPs */
3277 ret = -EINVAL;
3278 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3279 break;
3280 ret = -EFAULT;
3281 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
3282 break;
3283
3284 ret = tun_attach_filter(tun);
3285 break;
3286
3287 case TUNDETACHFILTER:
3288 /* Can be set only for TAPs */
3289 ret = -EINVAL;
3290 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3291 break;
3292 ret = 0;
3293 tun_detach_filter(tun, tun->numqueues);
3294 break;
3295
3296 case TUNGETFILTER:
3297 ret = -EINVAL;
3298 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3299 break;
3300 ret = -EFAULT;
3301 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
3302 break;
3303 ret = 0;
3304 break;
3305
3306 case TUNSETSTEERINGEBPF:
3307 ret = tun_set_ebpf(tun, &tun->steering_prog, argp);
3308 break;
3309
3310 case TUNSETFILTEREBPF:
3311 ret = tun_set_ebpf(tun, &tun->filter_prog, argp);
3312 break;
3313
3314 case TUNSETCARRIER:
3315 ret = -EFAULT;
3316 if (copy_from_user(&carrier, argp, sizeof(carrier)))
3317 goto unlock;
3318
3319 ret = tun_net_change_carrier(tun->dev, (bool)carrier);
3320 break;
3321
3322 case TUNGETDEVNETNS:
3323 ret = -EPERM;
3324 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3325 goto unlock;
3326 ret = open_related_ns(&net->ns, get_net_ns);
3327 break;
3328
3329 default:
3330 ret = -EINVAL;
3331 break;
3332 }
3333
3334 if (do_notify)
3335 netdev_state_change(tun->dev);
3336
3337 unlock:
3338 rtnl_unlock();
3339 if (tun)
3340 tun_put(tun);
3341 return ret;
3342 }
3343
3344 static long tun_chr_ioctl(struct file *file,
3345 unsigned int cmd, unsigned long arg)
3346 {
3347 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
3348 }
3349
3350 #ifdef CONFIG_COMPAT
3351 static long tun_chr_compat_ioctl(struct file *file,
3352 unsigned int cmd, unsigned long arg)
3353 {
3354 switch (cmd) {
3355 case TUNSETIFF:
3356 case TUNGETIFF:
3357 case TUNSETTXFILTER:
3358 case TUNGETSNDBUF:
3359 case TUNSETSNDBUF:
3360 case SIOCGIFHWADDR:
3361 case SIOCSIFHWADDR:
3362 arg = (unsigned long)compat_ptr(arg);
3363 break;
3364 default:
3365 arg = (compat_ulong_t)arg;
3366 break;
3367 }
3368
3369 /*
3370 * compat_ifreq is shorter than ifreq, so we must not access beyond
3371 * the end of that structure. All fields that are used in this
3372 * driver are compatible though, we don't need to convert the
3373 * contents.
3374 */
3375 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
3376 }
3377 #endif /* CONFIG_COMPAT */
3378
3379 static int tun_chr_fasync(int fd, struct file *file, int on)
3380 {
3381 struct tun_file *tfile = file->private_data;
3382 int ret;
3383
3384 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
3385 goto out;
3386
3387 if (on) {
3388 __f_setown(file, task_pid(current), PIDTYPE_TGID, 0);
3389 tfile->flags |= TUN_FASYNC;
3390 } else
3391 tfile->flags &= ~TUN_FASYNC;
3392 ret = 0;
3393 out:
3394 return ret;
3395 }
3396
3397 static int tun_chr_open(struct inode *inode, struct file * file)
3398 {
3399 struct net *net = current->nsproxy->net_ns;
3400 struct tun_file *tfile;
3401
3402 DBG1(KERN_INFO, "tunX: tun_chr_open\n");
3403
3404 tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
3405 &tun_proto, 0);
3406 if (!tfile)
3407 return -ENOMEM;
3408 if (ptr_ring_init(&tfile->tx_ring, 0, GFP_KERNEL)) {
3409 sk_free(&tfile->sk);
3410 return -ENOMEM;
3411 }
3412
3413 mutex_init(&tfile->napi_mutex);
3414 RCU_INIT_POINTER(tfile->tun, NULL);
3415 tfile->flags = 0;
3416 tfile->ifindex = 0;
3417
3418 init_waitqueue_head(&tfile->wq.wait);
3419 RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq);
3420
3421 tfile->socket.file = file;
3422 tfile->socket.ops = &tun_socket_ops;
3423
3424 sock_init_data(&tfile->socket, &tfile->sk);
3425
3426 tfile->sk.sk_write_space = tun_sock_write_space;
3427 tfile->sk.sk_sndbuf = INT_MAX;
3428
3429 file->private_data = tfile;
3430 INIT_LIST_HEAD(&tfile->next);
3431
3432 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
3433
3434 return 0;
3435 }
3436
3437 static int tun_chr_close(struct inode *inode, struct file *file)
3438 {
3439 struct tun_file *tfile = file->private_data;
3440
3441 tun_detach(tfile, true);
3442
3443 return 0;
3444 }
3445
3446 #ifdef CONFIG_PROC_FS
3447 static void tun_chr_show_fdinfo(struct seq_file *m, struct file *file)
3448 {
3449 struct tun_file *tfile = file->private_data;
3450 struct tun_struct *tun;
3451 struct ifreq ifr;
3452
3453 memset(&ifr, 0, sizeof(ifr));
3454
3455 rtnl_lock();
3456 tun = tun_get(tfile);
3457 if (tun)
3458 tun_get_iff(tun, &ifr);
3459 rtnl_unlock();
3460
3461 if (tun)
3462 tun_put(tun);
3463
3464 seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
3465 }
3466 #endif
3467
3468 static const struct file_operations tun_fops = {
3469 .owner = THIS_MODULE,
3470 .llseek = no_llseek,
3471 .read_iter = tun_chr_read_iter,
3472 .write_iter = tun_chr_write_iter,
3473 .poll = tun_chr_poll,
3474 .unlocked_ioctl = tun_chr_ioctl,
3475 #ifdef CONFIG_COMPAT
3476 .compat_ioctl = tun_chr_compat_ioctl,
3477 #endif
3478 .open = tun_chr_open,
3479 .release = tun_chr_close,
3480 .fasync = tun_chr_fasync,
3481 #ifdef CONFIG_PROC_FS
3482 .show_fdinfo = tun_chr_show_fdinfo,
3483 #endif
3484 };
3485
3486 static struct miscdevice tun_miscdev = {
3487 .minor = TUN_MINOR,
3488 .name = "tun",
3489 .nodename = "net/tun",
3490 .fops = &tun_fops,
3491 };
3492
3493 /* ethtool interface */
3494
3495 static void tun_default_link_ksettings(struct net_device *dev,
3496 struct ethtool_link_ksettings *cmd)
3497 {
3498 ethtool_link_ksettings_zero_link_mode(cmd, supported);
3499 ethtool_link_ksettings_zero_link_mode(cmd, advertising);
3500 cmd->base.speed = SPEED_10;
3501 cmd->base.duplex = DUPLEX_FULL;
3502 cmd->base.port = PORT_TP;
3503 cmd->base.phy_address = 0;
3504 cmd->base.autoneg = AUTONEG_DISABLE;
3505 }
3506
3507 static int tun_get_link_ksettings(struct net_device *dev,
3508 struct ethtool_link_ksettings *cmd)
3509 {
3510 struct tun_struct *tun = netdev_priv(dev);
3511
3512 memcpy(cmd, &tun->link_ksettings, sizeof(*cmd));
3513 return 0;
3514 }
3515
3516 static int tun_set_link_ksettings(struct net_device *dev,
3517 const struct ethtool_link_ksettings *cmd)
3518 {
3519 struct tun_struct *tun = netdev_priv(dev);
3520
3521 memcpy(&tun->link_ksettings, cmd, sizeof(*cmd));
3522 return 0;
3523 }
3524
3525 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
3526 {
3527 struct tun_struct *tun = netdev_priv(dev);
3528
3529 strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
3530 strlcpy(info->version, DRV_VERSION, sizeof(info->version));
3531
3532 switch (tun->flags & TUN_TYPE_MASK) {
3533 case IFF_TUN:
3534 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
3535 break;
3536 case IFF_TAP:
3537 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
3538 break;
3539 }
3540 }
3541
3542 static u32 tun_get_msglevel(struct net_device *dev)
3543 {
3544 #ifdef TUN_DEBUG
3545 struct tun_struct *tun = netdev_priv(dev);
3546 return tun->debug;
3547 #else
3548 return -EOPNOTSUPP;
3549 #endif
3550 }
3551
3552 static void tun_set_msglevel(struct net_device *dev, u32 value)
3553 {
3554 #ifdef TUN_DEBUG
3555 struct tun_struct *tun = netdev_priv(dev);
3556 tun->debug = value;
3557 #endif
3558 }
3559
3560 static int tun_get_coalesce(struct net_device *dev,
3561 struct ethtool_coalesce *ec)
3562 {
3563 struct tun_struct *tun = netdev_priv(dev);
3564
3565 ec->rx_max_coalesced_frames = tun->rx_batched;
3566
3567 return 0;
3568 }
3569
3570 static int tun_set_coalesce(struct net_device *dev,
3571 struct ethtool_coalesce *ec)
3572 {
3573 struct tun_struct *tun = netdev_priv(dev);
3574
3575 if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT)
3576 tun->rx_batched = NAPI_POLL_WEIGHT;
3577 else
3578 tun->rx_batched = ec->rx_max_coalesced_frames;
3579
3580 return 0;
3581 }
3582
3583 static const struct ethtool_ops tun_ethtool_ops = {
3584 .get_drvinfo = tun_get_drvinfo,
3585 .get_msglevel = tun_get_msglevel,
3586 .set_msglevel = tun_set_msglevel,
3587 .get_link = ethtool_op_get_link,
3588 .get_ts_info = ethtool_op_get_ts_info,
3589 .get_coalesce = tun_get_coalesce,
3590 .set_coalesce = tun_set_coalesce,
3591 .get_link_ksettings = tun_get_link_ksettings,
3592 .set_link_ksettings = tun_set_link_ksettings,
3593 };
3594
3595 static int tun_queue_resize(struct tun_struct *tun)
3596 {
3597 struct net_device *dev = tun->dev;
3598 struct tun_file *tfile;
3599 struct ptr_ring **rings;
3600 int n = tun->numqueues + tun->numdisabled;
3601 int ret, i;
3602
3603 rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL);
3604 if (!rings)
3605 return -ENOMEM;
3606
3607 for (i = 0; i < tun->numqueues; i++) {
3608 tfile = rtnl_dereference(tun->tfiles[i]);
3609 rings[i] = &tfile->tx_ring;
3610 }
3611 list_for_each_entry(tfile, &tun->disabled, next)
3612 rings[i++] = &tfile->tx_ring;
3613
3614 ret = ptr_ring_resize_multiple(rings, n,
3615 dev->tx_queue_len, GFP_KERNEL,
3616 tun_ptr_free);
3617
3618 kfree(rings);
3619 return ret;
3620 }
3621
3622 static int tun_device_event(struct notifier_block *unused,
3623 unsigned long event, void *ptr)
3624 {
3625 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3626 struct tun_struct *tun = netdev_priv(dev);
3627 int i;
3628
3629 if (dev->rtnl_link_ops != &tun_link_ops)
3630 return NOTIFY_DONE;
3631
3632 switch (event) {
3633 case NETDEV_CHANGE_TX_QUEUE_LEN:
3634 if (tun_queue_resize(tun))
3635 return NOTIFY_BAD;
3636 break;
3637 case NETDEV_UP:
3638 for (i = 0; i < tun->numqueues; i++) {
3639 struct tun_file *tfile;
3640
3641 tfile = rtnl_dereference(tun->tfiles[i]);
3642 tfile->socket.sk->sk_write_space(tfile->socket.sk);
3643 }
3644 break;
3645 default:
3646 break;
3647 }
3648
3649 return NOTIFY_DONE;
3650 }
3651
3652 static struct notifier_block tun_notifier_block __read_mostly = {
3653 .notifier_call = tun_device_event,
3654 };
3655
3656 static int __init tun_init(void)
3657 {
3658 int ret = 0;
3659
3660 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
3661
3662 ret = rtnl_link_register(&tun_link_ops);
3663 if (ret) {
3664 pr_err("Can't register link_ops\n");
3665 goto err_linkops;
3666 }
3667
3668 ret = misc_register(&tun_miscdev);
3669 if (ret) {
3670 pr_err("Can't register misc device %d\n", TUN_MINOR);
3671 goto err_misc;
3672 }
3673
3674 ret = register_netdevice_notifier(&tun_notifier_block);
3675 if (ret) {
3676 pr_err("Can't register netdevice notifier\n");
3677 goto err_notifier;
3678 }
3679
3680 return 0;
3681
3682 err_notifier:
3683 misc_deregister(&tun_miscdev);
3684 err_misc:
3685 rtnl_link_unregister(&tun_link_ops);
3686 err_linkops:
3687 return ret;
3688 }
3689
3690 static void tun_cleanup(void)
3691 {
3692 misc_deregister(&tun_miscdev);
3693 rtnl_link_unregister(&tun_link_ops);
3694 unregister_netdevice_notifier(&tun_notifier_block);
3695 }
3696
3697 /* Get an underlying socket object from tun file. Returns error unless file is
3698 * attached to a device. The returned object works like a packet socket, it
3699 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
3700 * holding a reference to the file for as long as the socket is in use. */
3701 struct socket *tun_get_socket(struct file *file)
3702 {
3703 struct tun_file *tfile;
3704 if (file->f_op != &tun_fops)
3705 return ERR_PTR(-EINVAL);
3706 tfile = file->private_data;
3707 if (!tfile)
3708 return ERR_PTR(-EBADFD);
3709 return &tfile->socket;
3710 }
3711 EXPORT_SYMBOL_GPL(tun_get_socket);
3712
3713 struct ptr_ring *tun_get_tx_ring(struct file *file)
3714 {
3715 struct tun_file *tfile;
3716
3717 if (file->f_op != &tun_fops)
3718 return ERR_PTR(-EINVAL);
3719 tfile = file->private_data;
3720 if (!tfile)
3721 return ERR_PTR(-EBADFD);
3722 return &tfile->tx_ring;
3723 }
3724 EXPORT_SYMBOL_GPL(tun_get_tx_ring);
3725
3726 module_init(tun_init);
3727 module_exit(tun_cleanup);
3728 MODULE_DESCRIPTION(DRV_DESCRIPTION);
3729 MODULE_AUTHOR(DRV_COPYRIGHT);
3730 MODULE_LICENSE("GPL");
3731 MODULE_ALIAS_MISCDEV(TUN_MINOR);
3732 MODULE_ALIAS("devname:net/tun");
Linux with added FPC-III support