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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 <net/ip_tunnels.h>
66#include <linux/seq_file.h>
67#include <linux/uio.h>
68#include <linux/skb_array.h>
69#include <linux/bpf.h>
70#include <linux/bpf_trace.h>
71#include <linux/mutex.h>
72#include <linux/ieee802154.h>
73#include <linux/if_ltalk.h>
74#include <uapi/linux/if_fddi.h>
75#include <uapi/linux/if_hippi.h>
76#include <uapi/linux/if_fc.h>
77#include <net/ax25.h>
78#include <net/rose.h>
79#include <net/6lowpan.h>
80
81#include <linux/uaccess.h>
82#include <linux/proc_fs.h>
83
84static void tun_default_link_ksettings(struct net_device *dev,
85 struct ethtool_link_ksettings *cmd);
86
87#define TUN_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
88
89/* TUN device flags */
90
91/* IFF_ATTACH_QUEUE is never stored in device flags,
92 * overload it to mean fasync when stored there.
93 */
94#define TUN_FASYNC IFF_ATTACH_QUEUE
95/* High bits in flags field are unused. */
96#define TUN_VNET_LE 0x80000000
97#define TUN_VNET_BE 0x40000000
98
99#define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
100 IFF_MULTI_QUEUE | IFF_NAPI | IFF_NAPI_FRAGS)
101
102#define GOODCOPY_LEN 128
103
104#define FLT_EXACT_COUNT 8
105struct tap_filter {
106 unsigned int count; /* Number of addrs. Zero means disabled */
107 u32 mask[2]; /* Mask of the hashed addrs */
108 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
109};
110
111/* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
112 * to max number of VCPUs in guest. */
113#define MAX_TAP_QUEUES 256
114#define MAX_TAP_FLOWS 4096
115
116#define TUN_FLOW_EXPIRE (3 * HZ)
117
118/* A tun_file connects an open character device to a tuntap netdevice. It
119 * also contains all socket related structures (except sock_fprog and tap_filter)
120 * to serve as one transmit queue for tuntap device. The sock_fprog and
121 * tap_filter were kept in tun_struct since they were used for filtering for the
122 * netdevice not for a specific queue (at least I didn't see the requirement for
123 * this).
124 *
125 * RCU usage:
126 * The tun_file and tun_struct are loosely coupled, the pointer from one to the
127 * other can only be read while rcu_read_lock or rtnl_lock is held.
128 */
129struct tun_file {
130 struct sock sk;
131 struct socket socket;
132 struct tun_struct __rcu *tun;
133 struct fasync_struct *fasync;
134 /* only used for fasnyc */
135 unsigned int flags;
136 union {
137 u16 queue_index;
138 unsigned int ifindex;
139 };
140 struct napi_struct napi;
141 bool napi_enabled;
142 bool napi_frags_enabled;
143 struct mutex napi_mutex; /* Protects access to the above napi */
144 struct list_head next;
145 struct tun_struct *detached;
146 struct ptr_ring tx_ring;
147 struct xdp_rxq_info xdp_rxq;
148};
149
150struct tun_page {
151 struct page *page;
152 int count;
153};
154
155struct tun_flow_entry {
156 struct hlist_node hash_link;
157 struct rcu_head rcu;
158 struct tun_struct *tun;
159
160 u32 rxhash;
161 u32 rps_rxhash;
162 int queue_index;
163 unsigned long updated ____cacheline_aligned_in_smp;
164};
165
166#define TUN_NUM_FLOW_ENTRIES 1024
167#define TUN_MASK_FLOW_ENTRIES (TUN_NUM_FLOW_ENTRIES - 1)
168
169struct tun_prog {
170 struct rcu_head rcu;
171 struct bpf_prog *prog;
172};
173
174/* Since the socket were moved to tun_file, to preserve the behavior of persist
175 * device, socket filter, sndbuf and vnet header size were restore when the
176 * file were attached to a persist device.
177 */
178struct tun_struct {
179 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES];
180 unsigned int numqueues;
181 unsigned int flags;
182 kuid_t owner;
183 kgid_t group;
184
185 struct net_device *dev;
186 netdev_features_t set_features;
187#define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
188 NETIF_F_TSO6 | NETIF_F_GSO_UDP_L4)
189
190 int align;
191 int vnet_hdr_sz;
192 int sndbuf;
193 struct tap_filter txflt;
194 struct sock_fprog fprog;
195 /* protected by rtnl lock */
196 bool filter_attached;
197 u32 msg_enable;
198 spinlock_t lock;
199 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
200 struct timer_list flow_gc_timer;
201 unsigned long ageing_time;
202 unsigned int numdisabled;
203 struct list_head disabled;
204 void *security;
205 u32 flow_count;
206 u32 rx_batched;
207 atomic_long_t rx_frame_errors;
208 struct bpf_prog __rcu *xdp_prog;
209 struct tun_prog __rcu *steering_prog;
210 struct tun_prog __rcu *filter_prog;
211 struct ethtool_link_ksettings link_ksettings;
212 /* init args */
213 struct file *file;
214 struct ifreq *ifr;
215};
216
217struct veth {
218 __be16 h_vlan_proto;
219 __be16 h_vlan_TCI;
220};
221
222static void tun_flow_init(struct tun_struct *tun);
223static void tun_flow_uninit(struct tun_struct *tun);
224
225static int tun_napi_receive(struct napi_struct *napi, int budget)
226{
227 struct tun_file *tfile = container_of(napi, struct tun_file, napi);
228 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
229 struct sk_buff_head process_queue;
230 struct sk_buff *skb;
231 int received = 0;
232
233 __skb_queue_head_init(&process_queue);
234
235 spin_lock(&queue->lock);
236 skb_queue_splice_tail_init(queue, &process_queue);
237 spin_unlock(&queue->lock);
238
239 while (received < budget && (skb = __skb_dequeue(&process_queue))) {
240 napi_gro_receive(napi, skb);
241 ++received;
242 }
243
244 if (!skb_queue_empty(&process_queue)) {
245 spin_lock(&queue->lock);
246 skb_queue_splice(&process_queue, queue);
247 spin_unlock(&queue->lock);
248 }
249
250 return received;
251}
252
253static int tun_napi_poll(struct napi_struct *napi, int budget)
254{
255 unsigned int received;
256
257 received = tun_napi_receive(napi, budget);
258
259 if (received < budget)
260 napi_complete_done(napi, received);
261
262 return received;
263}
264
265static void tun_napi_init(struct tun_struct *tun, struct tun_file *tfile,
266 bool napi_en, bool napi_frags)
267{
268 tfile->napi_enabled = napi_en;
269 tfile->napi_frags_enabled = napi_en && napi_frags;
270 if (napi_en) {
271 netif_napi_add_tx(tun->dev, &tfile->napi, tun_napi_poll);
272 napi_enable(&tfile->napi);
273 }
274}
275
276static void tun_napi_enable(struct tun_file *tfile)
277{
278 if (tfile->napi_enabled)
279 napi_enable(&tfile->napi);
280}
281
282static void tun_napi_disable(struct tun_file *tfile)
283{
284 if (tfile->napi_enabled)
285 napi_disable(&tfile->napi);
286}
287
288static void tun_napi_del(struct tun_file *tfile)
289{
290 if (tfile->napi_enabled)
291 netif_napi_del(&tfile->napi);
292}
293
294static bool tun_napi_frags_enabled(const struct tun_file *tfile)
295{
296 return tfile->napi_frags_enabled;
297}
298
299#ifdef CONFIG_TUN_VNET_CROSS_LE
300static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
301{
302 return tun->flags & TUN_VNET_BE ? false :
303 virtio_legacy_is_little_endian();
304}
305
306static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
307{
308 int be = !!(tun->flags & TUN_VNET_BE);
309
310 if (put_user(be, argp))
311 return -EFAULT;
312
313 return 0;
314}
315
316static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
317{
318 int be;
319
320 if (get_user(be, argp))
321 return -EFAULT;
322
323 if (be)
324 tun->flags |= TUN_VNET_BE;
325 else
326 tun->flags &= ~TUN_VNET_BE;
327
328 return 0;
329}
330#else
331static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
332{
333 return virtio_legacy_is_little_endian();
334}
335
336static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
337{
338 return -EINVAL;
339}
340
341static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
342{
343 return -EINVAL;
344}
345#endif /* CONFIG_TUN_VNET_CROSS_LE */
346
347static inline bool tun_is_little_endian(struct tun_struct *tun)
348{
349 return tun->flags & TUN_VNET_LE ||
350 tun_legacy_is_little_endian(tun);
351}
352
353static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
354{
355 return __virtio16_to_cpu(tun_is_little_endian(tun), val);
356}
357
358static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
359{
360 return __cpu_to_virtio16(tun_is_little_endian(tun), val);
361}
362
363static inline u32 tun_hashfn(u32 rxhash)
364{
365 return rxhash & TUN_MASK_FLOW_ENTRIES;
366}
367
368static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
369{
370 struct tun_flow_entry *e;
371
372 hlist_for_each_entry_rcu(e, head, hash_link) {
373 if (e->rxhash == rxhash)
374 return e;
375 }
376 return NULL;
377}
378
379static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
380 struct hlist_head *head,
381 u32 rxhash, u16 queue_index)
382{
383 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
384
385 if (e) {
386 netif_info(tun, tx_queued, tun->dev,
387 "create flow: hash %u index %u\n",
388 rxhash, queue_index);
389 e->updated = jiffies;
390 e->rxhash = rxhash;
391 e->rps_rxhash = 0;
392 e->queue_index = queue_index;
393 e->tun = tun;
394 hlist_add_head_rcu(&e->hash_link, head);
395 ++tun->flow_count;
396 }
397 return e;
398}
399
400static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
401{
402 netif_info(tun, tx_queued, tun->dev, "delete flow: hash %u index %u\n",
403 e->rxhash, e->queue_index);
404 hlist_del_rcu(&e->hash_link);
405 kfree_rcu(e, rcu);
406 --tun->flow_count;
407}
408
409static void tun_flow_flush(struct tun_struct *tun)
410{
411 int i;
412
413 spin_lock_bh(&tun->lock);
414 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
415 struct tun_flow_entry *e;
416 struct hlist_node *n;
417
418 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
419 tun_flow_delete(tun, e);
420 }
421 spin_unlock_bh(&tun->lock);
422}
423
424static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
425{
426 int i;
427
428 spin_lock_bh(&tun->lock);
429 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
430 struct tun_flow_entry *e;
431 struct hlist_node *n;
432
433 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
434 if (e->queue_index == queue_index)
435 tun_flow_delete(tun, e);
436 }
437 }
438 spin_unlock_bh(&tun->lock);
439}
440
441static void tun_flow_cleanup(struct timer_list *t)
442{
443 struct tun_struct *tun = from_timer(tun, t, flow_gc_timer);
444 unsigned long delay = tun->ageing_time;
445 unsigned long next_timer = jiffies + delay;
446 unsigned long count = 0;
447 int i;
448
449 spin_lock(&tun->lock);
450 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
451 struct tun_flow_entry *e;
452 struct hlist_node *n;
453
454 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
455 unsigned long this_timer;
456
457 this_timer = e->updated + delay;
458 if (time_before_eq(this_timer, jiffies)) {
459 tun_flow_delete(tun, e);
460 continue;
461 }
462 count++;
463 if (time_before(this_timer, next_timer))
464 next_timer = this_timer;
465 }
466 }
467
468 if (count)
469 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
470 spin_unlock(&tun->lock);
471}
472
473static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
474 struct tun_file *tfile)
475{
476 struct hlist_head *head;
477 struct tun_flow_entry *e;
478 unsigned long delay = tun->ageing_time;
479 u16 queue_index = tfile->queue_index;
480
481 head = &tun->flows[tun_hashfn(rxhash)];
482
483 rcu_read_lock();
484
485 e = tun_flow_find(head, rxhash);
486 if (likely(e)) {
487 /* TODO: keep queueing to old queue until it's empty? */
488 if (READ_ONCE(e->queue_index) != queue_index)
489 WRITE_ONCE(e->queue_index, queue_index);
490 if (e->updated != jiffies)
491 e->updated = jiffies;
492 sock_rps_record_flow_hash(e->rps_rxhash);
493 } else {
494 spin_lock_bh(&tun->lock);
495 if (!tun_flow_find(head, rxhash) &&
496 tun->flow_count < MAX_TAP_FLOWS)
497 tun_flow_create(tun, head, rxhash, queue_index);
498
499 if (!timer_pending(&tun->flow_gc_timer))
500 mod_timer(&tun->flow_gc_timer,
501 round_jiffies_up(jiffies + delay));
502 spin_unlock_bh(&tun->lock);
503 }
504
505 rcu_read_unlock();
506}
507
508/* Save the hash received in the stack receive path and update the
509 * flow_hash table accordingly.
510 */
511static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
512{
513 if (unlikely(e->rps_rxhash != hash))
514 e->rps_rxhash = hash;
515}
516
517/* We try to identify a flow through its rxhash. The reason that
518 * we do not check rxq no. is because some cards(e.g 82599), chooses
519 * the rxq based on the txq where the last packet of the flow comes. As
520 * the userspace application move between processors, we may get a
521 * different rxq no. here.
522 */
523static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb)
524{
525 struct tun_flow_entry *e;
526 u32 txq = 0;
527 u32 numqueues = 0;
528
529 numqueues = READ_ONCE(tun->numqueues);
530
531 txq = __skb_get_hash_symmetric(skb);
532 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
533 if (e) {
534 tun_flow_save_rps_rxhash(e, txq);
535 txq = e->queue_index;
536 } else {
537 /* use multiply and shift instead of expensive divide */
538 txq = ((u64)txq * numqueues) >> 32;
539 }
540
541 return txq;
542}
543
544static u16 tun_ebpf_select_queue(struct tun_struct *tun, struct sk_buff *skb)
545{
546 struct tun_prog *prog;
547 u32 numqueues;
548 u16 ret = 0;
549
550 numqueues = READ_ONCE(tun->numqueues);
551 if (!numqueues)
552 return 0;
553
554 prog = rcu_dereference(tun->steering_prog);
555 if (prog)
556 ret = bpf_prog_run_clear_cb(prog->prog, skb);
557
558 return ret % numqueues;
559}
560
561static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
562 struct net_device *sb_dev)
563{
564 struct tun_struct *tun = netdev_priv(dev);
565 u16 ret;
566
567 rcu_read_lock();
568 if (rcu_dereference(tun->steering_prog))
569 ret = tun_ebpf_select_queue(tun, skb);
570 else
571 ret = tun_automq_select_queue(tun, skb);
572 rcu_read_unlock();
573
574 return ret;
575}
576
577static inline bool tun_not_capable(struct tun_struct *tun)
578{
579 const struct cred *cred = current_cred();
580 struct net *net = dev_net(tun->dev);
581
582 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
583 (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
584 !ns_capable(net->user_ns, CAP_NET_ADMIN);
585}
586
587static void tun_set_real_num_queues(struct tun_struct *tun)
588{
589 netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
590 netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
591}
592
593static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
594{
595 tfile->detached = tun;
596 list_add_tail(&tfile->next, &tun->disabled);
597 ++tun->numdisabled;
598}
599
600static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
601{
602 struct tun_struct *tun = tfile->detached;
603
604 tfile->detached = NULL;
605 list_del_init(&tfile->next);
606 --tun->numdisabled;
607 return tun;
608}
609
610void tun_ptr_free(void *ptr)
611{
612 if (!ptr)
613 return;
614 if (tun_is_xdp_frame(ptr)) {
615 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
616
617 xdp_return_frame(xdpf);
618 } else {
619 __skb_array_destroy_skb(ptr);
620 }
621}
622EXPORT_SYMBOL_GPL(tun_ptr_free);
623
624static void tun_queue_purge(struct tun_file *tfile)
625{
626 void *ptr;
627
628 while ((ptr = ptr_ring_consume(&tfile->tx_ring)) != NULL)
629 tun_ptr_free(ptr);
630
631 skb_queue_purge(&tfile->sk.sk_write_queue);
632 skb_queue_purge(&tfile->sk.sk_error_queue);
633}
634
635static void __tun_detach(struct tun_file *tfile, bool clean)
636{
637 struct tun_file *ntfile;
638 struct tun_struct *tun;
639
640 tun = rtnl_dereference(tfile->tun);
641
642 if (tun && clean) {
643 if (!tfile->detached)
644 tun_napi_disable(tfile);
645 tun_napi_del(tfile);
646 }
647
648 if (tun && !tfile->detached) {
649 u16 index = tfile->queue_index;
650 BUG_ON(index >= tun->numqueues);
651
652 rcu_assign_pointer(tun->tfiles[index],
653 tun->tfiles[tun->numqueues - 1]);
654 ntfile = rtnl_dereference(tun->tfiles[index]);
655 ntfile->queue_index = index;
656 ntfile->xdp_rxq.queue_index = index;
657 rcu_assign_pointer(tun->tfiles[tun->numqueues - 1],
658 NULL);
659
660 --tun->numqueues;
661 if (clean) {
662 RCU_INIT_POINTER(tfile->tun, NULL);
663 sock_put(&tfile->sk);
664 } else {
665 tun_disable_queue(tun, tfile);
666 tun_napi_disable(tfile);
667 }
668
669 synchronize_net();
670 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
671 /* Drop read queue */
672 tun_queue_purge(tfile);
673 tun_set_real_num_queues(tun);
674 } else if (tfile->detached && clean) {
675 tun = tun_enable_queue(tfile);
676 sock_put(&tfile->sk);
677 }
678
679 if (clean) {
680 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
681 netif_carrier_off(tun->dev);
682
683 if (!(tun->flags & IFF_PERSIST) &&
684 tun->dev->reg_state == NETREG_REGISTERED)
685 unregister_netdevice(tun->dev);
686 }
687 if (tun)
688 xdp_rxq_info_unreg(&tfile->xdp_rxq);
689 ptr_ring_cleanup(&tfile->tx_ring, tun_ptr_free);
690 }
691}
692
693static void tun_detach(struct tun_file *tfile, bool clean)
694{
695 struct tun_struct *tun;
696 struct net_device *dev;
697
698 rtnl_lock();
699 tun = rtnl_dereference(tfile->tun);
700 dev = tun ? tun->dev : NULL;
701 __tun_detach(tfile, clean);
702 if (dev)
703 netdev_state_change(dev);
704 rtnl_unlock();
705
706 if (clean)
707 sock_put(&tfile->sk);
708}
709
710static void tun_detach_all(struct net_device *dev)
711{
712 struct tun_struct *tun = netdev_priv(dev);
713 struct tun_file *tfile, *tmp;
714 int i, n = tun->numqueues;
715
716 for (i = 0; i < n; i++) {
717 tfile = rtnl_dereference(tun->tfiles[i]);
718 BUG_ON(!tfile);
719 tun_napi_disable(tfile);
720 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
721 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
722 RCU_INIT_POINTER(tfile->tun, NULL);
723 --tun->numqueues;
724 }
725 list_for_each_entry(tfile, &tun->disabled, next) {
726 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
727 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
728 RCU_INIT_POINTER(tfile->tun, NULL);
729 }
730 BUG_ON(tun->numqueues != 0);
731
732 synchronize_net();
733 for (i = 0; i < n; i++) {
734 tfile = rtnl_dereference(tun->tfiles[i]);
735 tun_napi_del(tfile);
736 /* Drop read queue */
737 tun_queue_purge(tfile);
738 xdp_rxq_info_unreg(&tfile->xdp_rxq);
739 sock_put(&tfile->sk);
740 }
741 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
742 tun_napi_del(tfile);
743 tun_enable_queue(tfile);
744 tun_queue_purge(tfile);
745 xdp_rxq_info_unreg(&tfile->xdp_rxq);
746 sock_put(&tfile->sk);
747 }
748 BUG_ON(tun->numdisabled != 0);
749
750 if (tun->flags & IFF_PERSIST)
751 module_put(THIS_MODULE);
752}
753
754static int tun_attach(struct tun_struct *tun, struct file *file,
755 bool skip_filter, bool napi, bool napi_frags,
756 bool publish_tun)
757{
758 struct tun_file *tfile = file->private_data;
759 struct net_device *dev = tun->dev;
760 int err;
761
762 err = security_tun_dev_attach(tfile->socket.sk, tun->security);
763 if (err < 0)
764 goto out;
765
766 err = -EINVAL;
767 if (rtnl_dereference(tfile->tun) && !tfile->detached)
768 goto out;
769
770 err = -EBUSY;
771 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
772 goto out;
773
774 err = -E2BIG;
775 if (!tfile->detached &&
776 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
777 goto out;
778
779 err = 0;
780
781 /* Re-attach the filter to persist device */
782 if (!skip_filter && (tun->filter_attached == true)) {
783 lock_sock(tfile->socket.sk);
784 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
785 release_sock(tfile->socket.sk);
786 if (!err)
787 goto out;
788 }
789
790 if (!tfile->detached &&
791 ptr_ring_resize(&tfile->tx_ring, dev->tx_queue_len,
792 GFP_KERNEL, tun_ptr_free)) {
793 err = -ENOMEM;
794 goto out;
795 }
796
797 tfile->queue_index = tun->numqueues;
798 tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
799
800 if (tfile->detached) {
801 /* Re-attach detached tfile, updating XDP queue_index */
802 WARN_ON(!xdp_rxq_info_is_reg(&tfile->xdp_rxq));
803
804 if (tfile->xdp_rxq.queue_index != tfile->queue_index)
805 tfile->xdp_rxq.queue_index = tfile->queue_index;
806 } else {
807 /* Setup XDP RX-queue info, for new tfile getting attached */
808 err = xdp_rxq_info_reg(&tfile->xdp_rxq,
809 tun->dev, tfile->queue_index, 0);
810 if (err < 0)
811 goto out;
812 err = xdp_rxq_info_reg_mem_model(&tfile->xdp_rxq,
813 MEM_TYPE_PAGE_SHARED, NULL);
814 if (err < 0) {
815 xdp_rxq_info_unreg(&tfile->xdp_rxq);
816 goto out;
817 }
818 err = 0;
819 }
820
821 if (tfile->detached) {
822 tun_enable_queue(tfile);
823 tun_napi_enable(tfile);
824 } else {
825 sock_hold(&tfile->sk);
826 tun_napi_init(tun, tfile, napi, napi_frags);
827 }
828
829 if (rtnl_dereference(tun->xdp_prog))
830 sock_set_flag(&tfile->sk, SOCK_XDP);
831
832 /* device is allowed to go away first, so no need to hold extra
833 * refcnt.
834 */
835
836 /* Publish tfile->tun and tun->tfiles only after we've fully
837 * initialized tfile; otherwise we risk using half-initialized
838 * object.
839 */
840 if (publish_tun)
841 rcu_assign_pointer(tfile->tun, tun);
842 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
843 tun->numqueues++;
844 tun_set_real_num_queues(tun);
845out:
846 return err;
847}
848
849static struct tun_struct *tun_get(struct tun_file *tfile)
850{
851 struct tun_struct *tun;
852
853 rcu_read_lock();
854 tun = rcu_dereference(tfile->tun);
855 if (tun)
856 dev_hold(tun->dev);
857 rcu_read_unlock();
858
859 return tun;
860}
861
862static void tun_put(struct tun_struct *tun)
863{
864 dev_put(tun->dev);
865}
866
867/* TAP filtering */
868static void addr_hash_set(u32 *mask, const u8 *addr)
869{
870 int n = ether_crc(ETH_ALEN, addr) >> 26;
871 mask[n >> 5] |= (1 << (n & 31));
872}
873
874static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
875{
876 int n = ether_crc(ETH_ALEN, addr) >> 26;
877 return mask[n >> 5] & (1 << (n & 31));
878}
879
880static int update_filter(struct tap_filter *filter, void __user *arg)
881{
882 struct { u8 u[ETH_ALEN]; } *addr;
883 struct tun_filter uf;
884 int err, alen, n, nexact;
885
886 if (copy_from_user(&uf, arg, sizeof(uf)))
887 return -EFAULT;
888
889 if (!uf.count) {
890 /* Disabled */
891 filter->count = 0;
892 return 0;
893 }
894
895 alen = ETH_ALEN * uf.count;
896 addr = memdup_user(arg + sizeof(uf), alen);
897 if (IS_ERR(addr))
898 return PTR_ERR(addr);
899
900 /* The filter is updated without holding any locks. Which is
901 * perfectly safe. We disable it first and in the worst
902 * case we'll accept a few undesired packets. */
903 filter->count = 0;
904 wmb();
905
906 /* Use first set of addresses as an exact filter */
907 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
908 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
909
910 nexact = n;
911
912 /* Remaining multicast addresses are hashed,
913 * unicast will leave the filter disabled. */
914 memset(filter->mask, 0, sizeof(filter->mask));
915 for (; n < uf.count; n++) {
916 if (!is_multicast_ether_addr(addr[n].u)) {
917 err = 0; /* no filter */
918 goto free_addr;
919 }
920 addr_hash_set(filter->mask, addr[n].u);
921 }
922
923 /* For ALLMULTI just set the mask to all ones.
924 * This overrides the mask populated above. */
925 if ((uf.flags & TUN_FLT_ALLMULTI))
926 memset(filter->mask, ~0, sizeof(filter->mask));
927
928 /* Now enable the filter */
929 wmb();
930 filter->count = nexact;
931
932 /* Return the number of exact filters */
933 err = nexact;
934free_addr:
935 kfree(addr);
936 return err;
937}
938
939/* Returns: 0 - drop, !=0 - accept */
940static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
941{
942 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
943 * at this point. */
944 struct ethhdr *eh = (struct ethhdr *) skb->data;
945 int i;
946
947 /* Exact match */
948 for (i = 0; i < filter->count; i++)
949 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
950 return 1;
951
952 /* Inexact match (multicast only) */
953 if (is_multicast_ether_addr(eh->h_dest))
954 return addr_hash_test(filter->mask, eh->h_dest);
955
956 return 0;
957}
958
959/*
960 * Checks whether the packet is accepted or not.
961 * Returns: 0 - drop, !=0 - accept
962 */
963static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
964{
965 if (!filter->count)
966 return 1;
967
968 return run_filter(filter, skb);
969}
970
971/* Network device part of the driver */
972
973static const struct ethtool_ops tun_ethtool_ops;
974
975static int tun_net_init(struct net_device *dev)
976{
977 struct tun_struct *tun = netdev_priv(dev);
978 struct ifreq *ifr = tun->ifr;
979 int err;
980
981 dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
982 if (!dev->tstats)
983 return -ENOMEM;
984
985 spin_lock_init(&tun->lock);
986
987 err = security_tun_dev_alloc_security(&tun->security);
988 if (err < 0) {
989 free_percpu(dev->tstats);
990 return err;
991 }
992
993 tun_flow_init(tun);
994
995 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
996 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
997 NETIF_F_HW_VLAN_STAG_TX;
998 dev->features = dev->hw_features | NETIF_F_LLTX;
999 dev->vlan_features = dev->features &
1000 ~(NETIF_F_HW_VLAN_CTAG_TX |
1001 NETIF_F_HW_VLAN_STAG_TX);
1002
1003 tun->flags = (tun->flags & ~TUN_FEATURES) |
1004 (ifr->ifr_flags & TUN_FEATURES);
1005
1006 INIT_LIST_HEAD(&tun->disabled);
1007 err = tun_attach(tun, tun->file, false, ifr->ifr_flags & IFF_NAPI,
1008 ifr->ifr_flags & IFF_NAPI_FRAGS, false);
1009 if (err < 0) {
1010 tun_flow_uninit(tun);
1011 security_tun_dev_free_security(tun->security);
1012 free_percpu(dev->tstats);
1013 return err;
1014 }
1015 return 0;
1016}
1017
1018/* Net device detach from fd. */
1019static void tun_net_uninit(struct net_device *dev)
1020{
1021 tun_detach_all(dev);
1022}
1023
1024/* Net device open. */
1025static int tun_net_open(struct net_device *dev)
1026{
1027 netif_tx_start_all_queues(dev);
1028
1029 return 0;
1030}
1031
1032/* Net device close. */
1033static int tun_net_close(struct net_device *dev)
1034{
1035 netif_tx_stop_all_queues(dev);
1036 return 0;
1037}
1038
1039/* Net device start xmit */
1040static void tun_automq_xmit(struct tun_struct *tun, struct sk_buff *skb)
1041{
1042#ifdef CONFIG_RPS
1043 if (tun->numqueues == 1 && static_branch_unlikely(&rps_needed)) {
1044 /* Select queue was not called for the skbuff, so we extract the
1045 * RPS hash and save it into the flow_table here.
1046 */
1047 struct tun_flow_entry *e;
1048 __u32 rxhash;
1049
1050 rxhash = __skb_get_hash_symmetric(skb);
1051 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)], rxhash);
1052 if (e)
1053 tun_flow_save_rps_rxhash(e, rxhash);
1054 }
1055#endif
1056}
1057
1058static unsigned int run_ebpf_filter(struct tun_struct *tun,
1059 struct sk_buff *skb,
1060 int len)
1061{
1062 struct tun_prog *prog = rcu_dereference(tun->filter_prog);
1063
1064 if (prog)
1065 len = bpf_prog_run_clear_cb(prog->prog, skb);
1066
1067 return len;
1068}
1069
1070/* Net device start xmit */
1071static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
1072{
1073 struct tun_struct *tun = netdev_priv(dev);
1074 enum skb_drop_reason drop_reason;
1075 int txq = skb->queue_mapping;
1076 struct netdev_queue *queue;
1077 struct tun_file *tfile;
1078 int len = skb->len;
1079
1080 rcu_read_lock();
1081 tfile = rcu_dereference(tun->tfiles[txq]);
1082
1083 /* Drop packet if interface is not attached */
1084 if (!tfile) {
1085 drop_reason = SKB_DROP_REASON_DEV_READY;
1086 goto drop;
1087 }
1088
1089 if (!rcu_dereference(tun->steering_prog))
1090 tun_automq_xmit(tun, skb);
1091
1092 netif_info(tun, tx_queued, tun->dev, "%s %d\n", __func__, skb->len);
1093
1094 /* Drop if the filter does not like it.
1095 * This is a noop if the filter is disabled.
1096 * Filter can be enabled only for the TAP devices. */
1097 if (!check_filter(&tun->txflt, skb)) {
1098 drop_reason = SKB_DROP_REASON_TAP_TXFILTER;
1099 goto drop;
1100 }
1101
1102 if (tfile->socket.sk->sk_filter &&
1103 sk_filter(tfile->socket.sk, skb)) {
1104 drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
1105 goto drop;
1106 }
1107
1108 len = run_ebpf_filter(tun, skb, len);
1109 if (len == 0) {
1110 drop_reason = SKB_DROP_REASON_TAP_FILTER;
1111 goto drop;
1112 }
1113
1114 if (pskb_trim(skb, len)) {
1115 drop_reason = SKB_DROP_REASON_NOMEM;
1116 goto drop;
1117 }
1118
1119 if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC))) {
1120 drop_reason = SKB_DROP_REASON_SKB_UCOPY_FAULT;
1121 goto drop;
1122 }
1123
1124 skb_tx_timestamp(skb);
1125
1126 /* Orphan the skb - required as we might hang on to it
1127 * for indefinite time.
1128 */
1129 skb_orphan(skb);
1130
1131 nf_reset_ct(skb);
1132
1133 if (ptr_ring_produce(&tfile->tx_ring, skb)) {
1134 drop_reason = SKB_DROP_REASON_FULL_RING;
1135 goto drop;
1136 }
1137
1138 /* NETIF_F_LLTX requires to do our own update of trans_start */
1139 queue = netdev_get_tx_queue(dev, txq);
1140 txq_trans_cond_update(queue);
1141
1142 /* Notify and wake up reader process */
1143 if (tfile->flags & TUN_FASYNC)
1144 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1145 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1146
1147 rcu_read_unlock();
1148 return NETDEV_TX_OK;
1149
1150drop:
1151 dev_core_stats_tx_dropped_inc(dev);
1152 skb_tx_error(skb);
1153 kfree_skb_reason(skb, drop_reason);
1154 rcu_read_unlock();
1155 return NET_XMIT_DROP;
1156}
1157
1158static void tun_net_mclist(struct net_device *dev)
1159{
1160 /*
1161 * This callback is supposed to deal with mc filter in
1162 * _rx_ path and has nothing to do with the _tx_ path.
1163 * In rx path we always accept everything userspace gives us.
1164 */
1165}
1166
1167static netdev_features_t tun_net_fix_features(struct net_device *dev,
1168 netdev_features_t features)
1169{
1170 struct tun_struct *tun = netdev_priv(dev);
1171
1172 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
1173}
1174
1175static void tun_set_headroom(struct net_device *dev, int new_hr)
1176{
1177 struct tun_struct *tun = netdev_priv(dev);
1178
1179 if (new_hr < NET_SKB_PAD)
1180 new_hr = NET_SKB_PAD;
1181
1182 tun->align = new_hr;
1183}
1184
1185static void
1186tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
1187{
1188 struct tun_struct *tun = netdev_priv(dev);
1189
1190 dev_get_tstats64(dev, stats);
1191
1192 stats->rx_frame_errors +=
1193 (unsigned long)atomic_long_read(&tun->rx_frame_errors);
1194}
1195
1196static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1197 struct netlink_ext_ack *extack)
1198{
1199 struct tun_struct *tun = netdev_priv(dev);
1200 struct tun_file *tfile;
1201 struct bpf_prog *old_prog;
1202 int i;
1203
1204 old_prog = rtnl_dereference(tun->xdp_prog);
1205 rcu_assign_pointer(tun->xdp_prog, prog);
1206 if (old_prog)
1207 bpf_prog_put(old_prog);
1208
1209 for (i = 0; i < tun->numqueues; i++) {
1210 tfile = rtnl_dereference(tun->tfiles[i]);
1211 if (prog)
1212 sock_set_flag(&tfile->sk, SOCK_XDP);
1213 else
1214 sock_reset_flag(&tfile->sk, SOCK_XDP);
1215 }
1216 list_for_each_entry(tfile, &tun->disabled, next) {
1217 if (prog)
1218 sock_set_flag(&tfile->sk, SOCK_XDP);
1219 else
1220 sock_reset_flag(&tfile->sk, SOCK_XDP);
1221 }
1222
1223 return 0;
1224}
1225
1226static int tun_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1227{
1228 switch (xdp->command) {
1229 case XDP_SETUP_PROG:
1230 return tun_xdp_set(dev, xdp->prog, xdp->extack);
1231 default:
1232 return -EINVAL;
1233 }
1234}
1235
1236static int tun_net_change_carrier(struct net_device *dev, bool new_carrier)
1237{
1238 if (new_carrier) {
1239 struct tun_struct *tun = netdev_priv(dev);
1240
1241 if (!tun->numqueues)
1242 return -EPERM;
1243
1244 netif_carrier_on(dev);
1245 } else {
1246 netif_carrier_off(dev);
1247 }
1248 return 0;
1249}
1250
1251static const struct net_device_ops tun_netdev_ops = {
1252 .ndo_init = tun_net_init,
1253 .ndo_uninit = tun_net_uninit,
1254 .ndo_open = tun_net_open,
1255 .ndo_stop = tun_net_close,
1256 .ndo_start_xmit = tun_net_xmit,
1257 .ndo_fix_features = tun_net_fix_features,
1258 .ndo_select_queue = tun_select_queue,
1259 .ndo_set_rx_headroom = tun_set_headroom,
1260 .ndo_get_stats64 = tun_net_get_stats64,
1261 .ndo_change_carrier = tun_net_change_carrier,
1262};
1263
1264static void __tun_xdp_flush_tfile(struct tun_file *tfile)
1265{
1266 /* Notify and wake up reader process */
1267 if (tfile->flags & TUN_FASYNC)
1268 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1269 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1270}
1271
1272static int tun_xdp_xmit(struct net_device *dev, int n,
1273 struct xdp_frame **frames, u32 flags)
1274{
1275 struct tun_struct *tun = netdev_priv(dev);
1276 struct tun_file *tfile;
1277 u32 numqueues;
1278 int nxmit = 0;
1279 int i;
1280
1281 if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
1282 return -EINVAL;
1283
1284 rcu_read_lock();
1285
1286resample:
1287 numqueues = READ_ONCE(tun->numqueues);
1288 if (!numqueues) {
1289 rcu_read_unlock();
1290 return -ENXIO; /* Caller will free/return all frames */
1291 }
1292
1293 tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
1294 numqueues]);
1295 if (unlikely(!tfile))
1296 goto resample;
1297
1298 spin_lock(&tfile->tx_ring.producer_lock);
1299 for (i = 0; i < n; i++) {
1300 struct xdp_frame *xdp = frames[i];
1301 /* Encode the XDP flag into lowest bit for consumer to differ
1302 * XDP buffer from sk_buff.
1303 */
1304 void *frame = tun_xdp_to_ptr(xdp);
1305
1306 if (__ptr_ring_produce(&tfile->tx_ring, frame)) {
1307 dev_core_stats_tx_dropped_inc(dev);
1308 break;
1309 }
1310 nxmit++;
1311 }
1312 spin_unlock(&tfile->tx_ring.producer_lock);
1313
1314 if (flags & XDP_XMIT_FLUSH)
1315 __tun_xdp_flush_tfile(tfile);
1316
1317 rcu_read_unlock();
1318 return nxmit;
1319}
1320
1321static int tun_xdp_tx(struct net_device *dev, struct xdp_buff *xdp)
1322{
1323 struct xdp_frame *frame = xdp_convert_buff_to_frame(xdp);
1324 int nxmit;
1325
1326 if (unlikely(!frame))
1327 return -EOVERFLOW;
1328
1329 nxmit = tun_xdp_xmit(dev, 1, &frame, XDP_XMIT_FLUSH);
1330 if (!nxmit)
1331 xdp_return_frame_rx_napi(frame);
1332 return nxmit;
1333}
1334
1335static const struct net_device_ops tap_netdev_ops = {
1336 .ndo_init = tun_net_init,
1337 .ndo_uninit = tun_net_uninit,
1338 .ndo_open = tun_net_open,
1339 .ndo_stop = tun_net_close,
1340 .ndo_start_xmit = tun_net_xmit,
1341 .ndo_fix_features = tun_net_fix_features,
1342 .ndo_set_rx_mode = tun_net_mclist,
1343 .ndo_set_mac_address = eth_mac_addr,
1344 .ndo_validate_addr = eth_validate_addr,
1345 .ndo_select_queue = tun_select_queue,
1346 .ndo_features_check = passthru_features_check,
1347 .ndo_set_rx_headroom = tun_set_headroom,
1348 .ndo_get_stats64 = dev_get_tstats64,
1349 .ndo_bpf = tun_xdp,
1350 .ndo_xdp_xmit = tun_xdp_xmit,
1351 .ndo_change_carrier = tun_net_change_carrier,
1352};
1353
1354static void tun_flow_init(struct tun_struct *tun)
1355{
1356 int i;
1357
1358 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1359 INIT_HLIST_HEAD(&tun->flows[i]);
1360
1361 tun->ageing_time = TUN_FLOW_EXPIRE;
1362 timer_setup(&tun->flow_gc_timer, tun_flow_cleanup, 0);
1363 mod_timer(&tun->flow_gc_timer,
1364 round_jiffies_up(jiffies + tun->ageing_time));
1365}
1366
1367static void tun_flow_uninit(struct tun_struct *tun)
1368{
1369 del_timer_sync(&tun->flow_gc_timer);
1370 tun_flow_flush(tun);
1371}
1372
1373#define MIN_MTU 68
1374#define MAX_MTU 65535
1375
1376/* Initialize net device. */
1377static void tun_net_initialize(struct net_device *dev)
1378{
1379 struct tun_struct *tun = netdev_priv(dev);
1380
1381 switch (tun->flags & TUN_TYPE_MASK) {
1382 case IFF_TUN:
1383 dev->netdev_ops = &tun_netdev_ops;
1384 dev->header_ops = &ip_tunnel_header_ops;
1385
1386 /* Point-to-Point TUN Device */
1387 dev->hard_header_len = 0;
1388 dev->addr_len = 0;
1389 dev->mtu = 1500;
1390
1391 /* Zero header length */
1392 dev->type = ARPHRD_NONE;
1393 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1394 break;
1395
1396 case IFF_TAP:
1397 dev->netdev_ops = &tap_netdev_ops;
1398 /* Ethernet TAP Device */
1399 ether_setup(dev);
1400 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1401 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1402
1403 eth_hw_addr_random(dev);
1404
1405 /* Currently tun does not support XDP, only tap does. */
1406 dev->xdp_features = NETDEV_XDP_ACT_BASIC |
1407 NETDEV_XDP_ACT_REDIRECT |
1408 NETDEV_XDP_ACT_NDO_XMIT;
1409
1410 break;
1411 }
1412
1413 dev->min_mtu = MIN_MTU;
1414 dev->max_mtu = MAX_MTU - dev->hard_header_len;
1415}
1416
1417static bool tun_sock_writeable(struct tun_struct *tun, struct tun_file *tfile)
1418{
1419 struct sock *sk = tfile->socket.sk;
1420
1421 return (tun->dev->flags & IFF_UP) && sock_writeable(sk);
1422}
1423
1424/* Character device part */
1425
1426/* Poll */
1427static __poll_t tun_chr_poll(struct file *file, poll_table *wait)
1428{
1429 struct tun_file *tfile = file->private_data;
1430 struct tun_struct *tun = tun_get(tfile);
1431 struct sock *sk;
1432 __poll_t mask = 0;
1433
1434 if (!tun)
1435 return EPOLLERR;
1436
1437 sk = tfile->socket.sk;
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
1461static 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 len > (ETH_MAX_MTU - NET_SKB_PAD - NET_IP_ALIGN))
1472 return ERR_PTR(-EMSGSIZE);
1473
1474 local_bh_disable();
1475 skb = napi_get_frags(&tfile->napi);
1476 local_bh_enable();
1477 if (!skb)
1478 return ERR_PTR(-ENOMEM);
1479
1480 linear = iov_iter_single_seg_count(it);
1481 err = __skb_grow(skb, linear);
1482 if (err)
1483 goto free;
1484
1485 skb->len = len;
1486 skb->data_len = len - linear;
1487 skb->truesize += skb->data_len;
1488
1489 for (i = 1; i < it->nr_segs; i++) {
1490 const struct iovec *iov = iter_iov(it);
1491 size_t fragsz = iov->iov_len;
1492 struct page *page;
1493 void *frag;
1494
1495 if (fragsz == 0 || fragsz > PAGE_SIZE) {
1496 err = -EINVAL;
1497 goto free;
1498 }
1499 frag = netdev_alloc_frag(fragsz);
1500 if (!frag) {
1501 err = -ENOMEM;
1502 goto free;
1503 }
1504 page = virt_to_head_page(frag);
1505 skb_fill_page_desc(skb, i - 1, page,
1506 frag - page_address(page), fragsz);
1507 }
1508
1509 return skb;
1510free:
1511 /* frees skb and all frags allocated with napi_alloc_frag() */
1512 napi_free_frags(&tfile->napi);
1513 return ERR_PTR(err);
1514}
1515
1516/* prepad is the amount to reserve at front. len is length after that.
1517 * linear is a hint as to how much to copy (usually headers). */
1518static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1519 size_t prepad, size_t len,
1520 size_t linear, int noblock)
1521{
1522 struct sock *sk = tfile->socket.sk;
1523 struct sk_buff *skb;
1524 int err;
1525
1526 /* Under a page? Don't bother with paged skb. */
1527 if (prepad + len < PAGE_SIZE)
1528 linear = len;
1529
1530 if (len - linear > MAX_SKB_FRAGS * (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER))
1531 linear = len - MAX_SKB_FRAGS * (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER);
1532 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1533 &err, PAGE_ALLOC_COSTLY_ORDER);
1534 if (!skb)
1535 return ERR_PTR(err);
1536
1537 skb_reserve(skb, prepad);
1538 skb_put(skb, linear);
1539 skb->data_len = len - linear;
1540 skb->len += len - linear;
1541
1542 return skb;
1543}
1544
1545static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile,
1546 struct sk_buff *skb, int more)
1547{
1548 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1549 struct sk_buff_head process_queue;
1550 u32 rx_batched = tun->rx_batched;
1551 bool rcv = false;
1552
1553 if (!rx_batched || (!more && skb_queue_empty(queue))) {
1554 local_bh_disable();
1555 skb_record_rx_queue(skb, tfile->queue_index);
1556 netif_receive_skb(skb);
1557 local_bh_enable();
1558 return;
1559 }
1560
1561 spin_lock(&queue->lock);
1562 if (!more || skb_queue_len(queue) == rx_batched) {
1563 __skb_queue_head_init(&process_queue);
1564 skb_queue_splice_tail_init(queue, &process_queue);
1565 rcv = true;
1566 } else {
1567 __skb_queue_tail(queue, skb);
1568 }
1569 spin_unlock(&queue->lock);
1570
1571 if (rcv) {
1572 struct sk_buff *nskb;
1573
1574 local_bh_disable();
1575 while ((nskb = __skb_dequeue(&process_queue))) {
1576 skb_record_rx_queue(nskb, tfile->queue_index);
1577 netif_receive_skb(nskb);
1578 }
1579 skb_record_rx_queue(skb, tfile->queue_index);
1580 netif_receive_skb(skb);
1581 local_bh_enable();
1582 }
1583}
1584
1585static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile,
1586 int len, int noblock, bool zerocopy)
1587{
1588 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
1589 return false;
1590
1591 if (tfile->socket.sk->sk_sndbuf != INT_MAX)
1592 return false;
1593
1594 if (!noblock)
1595 return false;
1596
1597 if (zerocopy)
1598 return false;
1599
1600 if (SKB_DATA_ALIGN(len + TUN_RX_PAD + XDP_PACKET_HEADROOM) +
1601 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
1602 return false;
1603
1604 return true;
1605}
1606
1607static struct sk_buff *__tun_build_skb(struct tun_file *tfile,
1608 struct page_frag *alloc_frag, char *buf,
1609 int buflen, int len, int pad)
1610{
1611 struct sk_buff *skb = build_skb(buf, buflen);
1612
1613 if (!skb)
1614 return ERR_PTR(-ENOMEM);
1615
1616 skb_reserve(skb, pad);
1617 skb_put(skb, len);
1618 skb_set_owner_w(skb, tfile->socket.sk);
1619
1620 get_page(alloc_frag->page);
1621 alloc_frag->offset += buflen;
1622
1623 return skb;
1624}
1625
1626static int tun_xdp_act(struct tun_struct *tun, struct bpf_prog *xdp_prog,
1627 struct xdp_buff *xdp, u32 act)
1628{
1629 int err;
1630
1631 switch (act) {
1632 case XDP_REDIRECT:
1633 err = xdp_do_redirect(tun->dev, xdp, xdp_prog);
1634 if (err) {
1635 dev_core_stats_rx_dropped_inc(tun->dev);
1636 return err;
1637 }
1638 dev_sw_netstats_rx_add(tun->dev, xdp->data_end - xdp->data);
1639 break;
1640 case XDP_TX:
1641 err = tun_xdp_tx(tun->dev, xdp);
1642 if (err < 0) {
1643 dev_core_stats_rx_dropped_inc(tun->dev);
1644 return err;
1645 }
1646 dev_sw_netstats_rx_add(tun->dev, xdp->data_end - xdp->data);
1647 break;
1648 case XDP_PASS:
1649 break;
1650 default:
1651 bpf_warn_invalid_xdp_action(tun->dev, xdp_prog, act);
1652 fallthrough;
1653 case XDP_ABORTED:
1654 trace_xdp_exception(tun->dev, xdp_prog, act);
1655 fallthrough;
1656 case XDP_DROP:
1657 dev_core_stats_rx_dropped_inc(tun->dev);
1658 break;
1659 }
1660
1661 return act;
1662}
1663
1664static struct sk_buff *tun_build_skb(struct tun_struct *tun,
1665 struct tun_file *tfile,
1666 struct iov_iter *from,
1667 struct virtio_net_hdr *hdr,
1668 int len, int *skb_xdp)
1669{
1670 struct page_frag *alloc_frag = ¤t->task_frag;
1671 struct bpf_prog *xdp_prog;
1672 int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1673 char *buf;
1674 size_t copied;
1675 int pad = TUN_RX_PAD;
1676 int err = 0;
1677
1678 rcu_read_lock();
1679 xdp_prog = rcu_dereference(tun->xdp_prog);
1680 if (xdp_prog)
1681 pad += XDP_PACKET_HEADROOM;
1682 buflen += SKB_DATA_ALIGN(len + pad);
1683 rcu_read_unlock();
1684
1685 alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES);
1686 if (unlikely(!skb_page_frag_refill(buflen, alloc_frag, GFP_KERNEL)))
1687 return ERR_PTR(-ENOMEM);
1688
1689 buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
1690 copied = copy_page_from_iter(alloc_frag->page,
1691 alloc_frag->offset + pad,
1692 len, from);
1693 if (copied != len)
1694 return ERR_PTR(-EFAULT);
1695
1696 /* There's a small window that XDP may be set after the check
1697 * of xdp_prog above, this should be rare and for simplicity
1698 * we do XDP on skb in case the headroom is not enough.
1699 */
1700 if (hdr->gso_type || !xdp_prog) {
1701 *skb_xdp = 1;
1702 return __tun_build_skb(tfile, alloc_frag, buf, buflen, len,
1703 pad);
1704 }
1705
1706 *skb_xdp = 0;
1707
1708 local_bh_disable();
1709 rcu_read_lock();
1710 xdp_prog = rcu_dereference(tun->xdp_prog);
1711 if (xdp_prog) {
1712 struct xdp_buff xdp;
1713 u32 act;
1714
1715 xdp_init_buff(&xdp, buflen, &tfile->xdp_rxq);
1716 xdp_prepare_buff(&xdp, buf, pad, len, false);
1717
1718 act = bpf_prog_run_xdp(xdp_prog, &xdp);
1719 if (act == XDP_REDIRECT || act == XDP_TX) {
1720 get_page(alloc_frag->page);
1721 alloc_frag->offset += buflen;
1722 }
1723 err = tun_xdp_act(tun, xdp_prog, &xdp, act);
1724 if (err < 0) {
1725 if (act == XDP_REDIRECT || act == XDP_TX)
1726 put_page(alloc_frag->page);
1727 goto out;
1728 }
1729
1730 if (err == XDP_REDIRECT)
1731 xdp_do_flush();
1732 if (err != XDP_PASS)
1733 goto out;
1734
1735 pad = xdp.data - xdp.data_hard_start;
1736 len = xdp.data_end - xdp.data;
1737 }
1738 rcu_read_unlock();
1739 local_bh_enable();
1740
1741 return __tun_build_skb(tfile, alloc_frag, buf, buflen, len, pad);
1742
1743out:
1744 rcu_read_unlock();
1745 local_bh_enable();
1746 return NULL;
1747}
1748
1749/* Get packet from user space buffer */
1750static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1751 void *msg_control, struct iov_iter *from,
1752 int noblock, bool more)
1753{
1754 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1755 struct sk_buff *skb;
1756 size_t total_len = iov_iter_count(from);
1757 size_t len = total_len, align = tun->align, linear;
1758 struct virtio_net_hdr gso = { 0 };
1759 int good_linear;
1760 int copylen;
1761 bool zerocopy = false;
1762 int err;
1763 u32 rxhash = 0;
1764 int skb_xdp = 1;
1765 bool frags = tun_napi_frags_enabled(tfile);
1766 enum skb_drop_reason drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
1767
1768 if (!(tun->flags & IFF_NO_PI)) {
1769 if (len < sizeof(pi))
1770 return -EINVAL;
1771 len -= sizeof(pi);
1772
1773 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1774 return -EFAULT;
1775 }
1776
1777 if (tun->flags & IFF_VNET_HDR) {
1778 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1779
1780 if (len < vnet_hdr_sz)
1781 return -EINVAL;
1782 len -= vnet_hdr_sz;
1783
1784 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1785 return -EFAULT;
1786
1787 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1788 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1789 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1790
1791 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1792 return -EINVAL;
1793 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1794 }
1795
1796 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1797 align += NET_IP_ALIGN;
1798 if (unlikely(len < ETH_HLEN ||
1799 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1800 return -EINVAL;
1801 }
1802
1803 good_linear = SKB_MAX_HEAD(align);
1804
1805 if (msg_control) {
1806 struct iov_iter i = *from;
1807
1808 /* There are 256 bytes to be copied in skb, so there is
1809 * enough room for skb expand head in case it is used.
1810 * The rest of the buffer is mapped from userspace.
1811 */
1812 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1813 if (copylen > good_linear)
1814 copylen = good_linear;
1815 linear = copylen;
1816 iov_iter_advance(&i, copylen);
1817 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1818 zerocopy = true;
1819 }
1820
1821 if (!frags && tun_can_build_skb(tun, tfile, len, noblock, zerocopy)) {
1822 /* For the packet that is not easy to be processed
1823 * (e.g gso or jumbo packet), we will do it at after
1824 * skb was created with generic XDP routine.
1825 */
1826 skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp);
1827 err = PTR_ERR_OR_ZERO(skb);
1828 if (err)
1829 goto drop;
1830 if (!skb)
1831 return total_len;
1832 } else {
1833 if (!zerocopy) {
1834 copylen = len;
1835 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1836 linear = good_linear;
1837 else
1838 linear = tun16_to_cpu(tun, gso.hdr_len);
1839 }
1840
1841 if (frags) {
1842 mutex_lock(&tfile->napi_mutex);
1843 skb = tun_napi_alloc_frags(tfile, copylen, from);
1844 /* tun_napi_alloc_frags() enforces a layout for the skb.
1845 * If zerocopy is enabled, then this layout will be
1846 * overwritten by zerocopy_sg_from_iter().
1847 */
1848 zerocopy = false;
1849 } else {
1850 if (!linear)
1851 linear = min_t(size_t, good_linear, copylen);
1852
1853 skb = tun_alloc_skb(tfile, align, copylen, linear,
1854 noblock);
1855 }
1856
1857 err = PTR_ERR_OR_ZERO(skb);
1858 if (err)
1859 goto drop;
1860
1861 if (zerocopy)
1862 err = zerocopy_sg_from_iter(skb, from);
1863 else
1864 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1865
1866 if (err) {
1867 err = -EFAULT;
1868 drop_reason = SKB_DROP_REASON_SKB_UCOPY_FAULT;
1869 goto drop;
1870 }
1871 }
1872
1873 if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1874 atomic_long_inc(&tun->rx_frame_errors);
1875 err = -EINVAL;
1876 goto free_skb;
1877 }
1878
1879 switch (tun->flags & TUN_TYPE_MASK) {
1880 case IFF_TUN:
1881 if (tun->flags & IFF_NO_PI) {
1882 u8 ip_version = skb->len ? (skb->data[0] >> 4) : 0;
1883
1884 switch (ip_version) {
1885 case 4:
1886 pi.proto = htons(ETH_P_IP);
1887 break;
1888 case 6:
1889 pi.proto = htons(ETH_P_IPV6);
1890 break;
1891 default:
1892 err = -EINVAL;
1893 goto drop;
1894 }
1895 }
1896
1897 skb_reset_mac_header(skb);
1898 skb->protocol = pi.proto;
1899 skb->dev = tun->dev;
1900 break;
1901 case IFF_TAP:
1902 if (frags && !pskb_may_pull(skb, ETH_HLEN)) {
1903 err = -ENOMEM;
1904 drop_reason = SKB_DROP_REASON_HDR_TRUNC;
1905 goto drop;
1906 }
1907 skb->protocol = eth_type_trans(skb, tun->dev);
1908 break;
1909 }
1910
1911 /* copy skb_ubuf_info for callback when skb has no error */
1912 if (zerocopy) {
1913 skb_zcopy_init(skb, msg_control);
1914 } else if (msg_control) {
1915 struct ubuf_info *uarg = msg_control;
1916 uarg->callback(NULL, uarg, false);
1917 }
1918
1919 skb_reset_network_header(skb);
1920 skb_probe_transport_header(skb);
1921 skb_record_rx_queue(skb, tfile->queue_index);
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 goto unlock_frags;
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 drop_reason = SKB_DROP_REASON_DEV_READY;
1955 goto drop;
1956 }
1957
1958 if (frags) {
1959 u32 headlen;
1960
1961 /* Exercise flow dissector code path. */
1962 skb_push(skb, ETH_HLEN);
1963 headlen = eth_get_headlen(tun->dev, skb->data,
1964 skb_headlen(skb));
1965
1966 if (unlikely(headlen > skb_headlen(skb))) {
1967 WARN_ON_ONCE(1);
1968 err = -ENOMEM;
1969 dev_core_stats_rx_dropped_inc(tun->dev);
1970napi_busy:
1971 napi_free_frags(&tfile->napi);
1972 rcu_read_unlock();
1973 mutex_unlock(&tfile->napi_mutex);
1974 return err;
1975 }
1976
1977 if (likely(napi_schedule_prep(&tfile->napi))) {
1978 local_bh_disable();
1979 napi_gro_frags(&tfile->napi);
1980 napi_complete(&tfile->napi);
1981 local_bh_enable();
1982 } else {
1983 err = -EBUSY;
1984 goto napi_busy;
1985 }
1986 mutex_unlock(&tfile->napi_mutex);
1987 } else if (tfile->napi_enabled) {
1988 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1989 int queue_len;
1990
1991 spin_lock_bh(&queue->lock);
1992
1993 if (unlikely(tfile->detached)) {
1994 spin_unlock_bh(&queue->lock);
1995 rcu_read_unlock();
1996 err = -EBUSY;
1997 goto free_skb;
1998 }
1999
2000 __skb_queue_tail(queue, skb);
2001 queue_len = skb_queue_len(queue);
2002 spin_unlock(&queue->lock);
2003
2004 if (!more || queue_len > NAPI_POLL_WEIGHT)
2005 napi_schedule(&tfile->napi);
2006
2007 local_bh_enable();
2008 } else if (!IS_ENABLED(CONFIG_4KSTACKS)) {
2009 tun_rx_batched(tun, tfile, skb, more);
2010 } else {
2011 netif_rx(skb);
2012 }
2013 rcu_read_unlock();
2014
2015 preempt_disable();
2016 dev_sw_netstats_rx_add(tun->dev, len);
2017 preempt_enable();
2018
2019 if (rxhash)
2020 tun_flow_update(tun, rxhash, tfile);
2021
2022 return total_len;
2023
2024drop:
2025 if (err != -EAGAIN)
2026 dev_core_stats_rx_dropped_inc(tun->dev);
2027
2028free_skb:
2029 if (!IS_ERR_OR_NULL(skb))
2030 kfree_skb_reason(skb, drop_reason);
2031
2032unlock_frags:
2033 if (frags) {
2034 tfile->napi.skb = NULL;
2035 mutex_unlock(&tfile->napi_mutex);
2036 }
2037
2038 return err ?: total_len;
2039}
2040
2041static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
2042{
2043 struct file *file = iocb->ki_filp;
2044 struct tun_file *tfile = file->private_data;
2045 struct tun_struct *tun = tun_get(tfile);
2046 ssize_t result;
2047 int noblock = 0;
2048
2049 if (!tun)
2050 return -EBADFD;
2051
2052 if ((file->f_flags & O_NONBLOCK) || (iocb->ki_flags & IOCB_NOWAIT))
2053 noblock = 1;
2054
2055 result = tun_get_user(tun, tfile, NULL, from, noblock, false);
2056
2057 tun_put(tun);
2058 return result;
2059}
2060
2061static ssize_t tun_put_user_xdp(struct tun_struct *tun,
2062 struct tun_file *tfile,
2063 struct xdp_frame *xdp_frame,
2064 struct iov_iter *iter)
2065{
2066 int vnet_hdr_sz = 0;
2067 size_t size = xdp_frame->len;
2068 size_t ret;
2069
2070 if (tun->flags & IFF_VNET_HDR) {
2071 struct virtio_net_hdr gso = { 0 };
2072
2073 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2074 if (unlikely(iov_iter_count(iter) < vnet_hdr_sz))
2075 return -EINVAL;
2076 if (unlikely(copy_to_iter(&gso, sizeof(gso), iter) !=
2077 sizeof(gso)))
2078 return -EFAULT;
2079 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2080 }
2081
2082 ret = copy_to_iter(xdp_frame->data, size, iter) + vnet_hdr_sz;
2083
2084 preempt_disable();
2085 dev_sw_netstats_tx_add(tun->dev, 1, ret);
2086 preempt_enable();
2087
2088 return ret;
2089}
2090
2091/* Put packet to the user space buffer */
2092static ssize_t tun_put_user(struct tun_struct *tun,
2093 struct tun_file *tfile,
2094 struct sk_buff *skb,
2095 struct iov_iter *iter)
2096{
2097 struct tun_pi pi = { 0, skb->protocol };
2098 ssize_t total;
2099 int vlan_offset = 0;
2100 int vlan_hlen = 0;
2101 int vnet_hdr_sz = 0;
2102
2103 if (skb_vlan_tag_present(skb))
2104 vlan_hlen = VLAN_HLEN;
2105
2106 if (tun->flags & IFF_VNET_HDR)
2107 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2108
2109 total = skb->len + vlan_hlen + vnet_hdr_sz;
2110
2111 if (!(tun->flags & IFF_NO_PI)) {
2112 if (iov_iter_count(iter) < sizeof(pi))
2113 return -EINVAL;
2114
2115 total += sizeof(pi);
2116 if (iov_iter_count(iter) < total) {
2117 /* Packet will be striped */
2118 pi.flags |= TUN_PKT_STRIP;
2119 }
2120
2121 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
2122 return -EFAULT;
2123 }
2124
2125 if (vnet_hdr_sz) {
2126 struct virtio_net_hdr gso;
2127
2128 if (iov_iter_count(iter) < vnet_hdr_sz)
2129 return -EINVAL;
2130
2131 if (virtio_net_hdr_from_skb(skb, &gso,
2132 tun_is_little_endian(tun), true,
2133 vlan_hlen)) {
2134 struct skb_shared_info *sinfo = skb_shinfo(skb);
2135 pr_err("unexpected GSO type: "
2136 "0x%x, gso_size %d, hdr_len %d\n",
2137 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
2138 tun16_to_cpu(tun, gso.hdr_len));
2139 print_hex_dump(KERN_ERR, "tun: ",
2140 DUMP_PREFIX_NONE,
2141 16, 1, skb->head,
2142 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
2143 WARN_ON_ONCE(1);
2144 return -EINVAL;
2145 }
2146
2147 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
2148 return -EFAULT;
2149
2150 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2151 }
2152
2153 if (vlan_hlen) {
2154 int ret;
2155 struct veth veth;
2156
2157 veth.h_vlan_proto = skb->vlan_proto;
2158 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
2159
2160 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
2161
2162 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
2163 if (ret || !iov_iter_count(iter))
2164 goto done;
2165
2166 ret = copy_to_iter(&veth, sizeof(veth), iter);
2167 if (ret != sizeof(veth) || !iov_iter_count(iter))
2168 goto done;
2169 }
2170
2171 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
2172
2173done:
2174 /* caller is in process context, */
2175 preempt_disable();
2176 dev_sw_netstats_tx_add(tun->dev, 1, skb->len + vlan_hlen);
2177 preempt_enable();
2178
2179 return total;
2180}
2181
2182static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err)
2183{
2184 DECLARE_WAITQUEUE(wait, current);
2185 void *ptr = NULL;
2186 int error = 0;
2187
2188 ptr = ptr_ring_consume(&tfile->tx_ring);
2189 if (ptr)
2190 goto out;
2191 if (noblock) {
2192 error = -EAGAIN;
2193 goto out;
2194 }
2195
2196 add_wait_queue(&tfile->socket.wq.wait, &wait);
2197
2198 while (1) {
2199 set_current_state(TASK_INTERRUPTIBLE);
2200 ptr = ptr_ring_consume(&tfile->tx_ring);
2201 if (ptr)
2202 break;
2203 if (signal_pending(current)) {
2204 error = -ERESTARTSYS;
2205 break;
2206 }
2207 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
2208 error = -EFAULT;
2209 break;
2210 }
2211
2212 schedule();
2213 }
2214
2215 __set_current_state(TASK_RUNNING);
2216 remove_wait_queue(&tfile->socket.wq.wait, &wait);
2217
2218out:
2219 *err = error;
2220 return ptr;
2221}
2222
2223static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
2224 struct iov_iter *to,
2225 int noblock, void *ptr)
2226{
2227 ssize_t ret;
2228 int err;
2229
2230 if (!iov_iter_count(to)) {
2231 tun_ptr_free(ptr);
2232 return 0;
2233 }
2234
2235 if (!ptr) {
2236 /* Read frames from ring */
2237 ptr = tun_ring_recv(tfile, noblock, &err);
2238 if (!ptr)
2239 return err;
2240 }
2241
2242 if (tun_is_xdp_frame(ptr)) {
2243 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2244
2245 ret = tun_put_user_xdp(tun, tfile, xdpf, to);
2246 xdp_return_frame(xdpf);
2247 } else {
2248 struct sk_buff *skb = ptr;
2249
2250 ret = tun_put_user(tun, tfile, skb, to);
2251 if (unlikely(ret < 0))
2252 kfree_skb(skb);
2253 else
2254 consume_skb(skb);
2255 }
2256
2257 return ret;
2258}
2259
2260static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
2261{
2262 struct file *file = iocb->ki_filp;
2263 struct tun_file *tfile = file->private_data;
2264 struct tun_struct *tun = tun_get(tfile);
2265 ssize_t len = iov_iter_count(to), ret;
2266 int noblock = 0;
2267
2268 if (!tun)
2269 return -EBADFD;
2270
2271 if ((file->f_flags & O_NONBLOCK) || (iocb->ki_flags & IOCB_NOWAIT))
2272 noblock = 1;
2273
2274 ret = tun_do_read(tun, tfile, to, noblock, NULL);
2275 ret = min_t(ssize_t, ret, len);
2276 if (ret > 0)
2277 iocb->ki_pos = ret;
2278 tun_put(tun);
2279 return ret;
2280}
2281
2282static void tun_prog_free(struct rcu_head *rcu)
2283{
2284 struct tun_prog *prog = container_of(rcu, struct tun_prog, rcu);
2285
2286 bpf_prog_destroy(prog->prog);
2287 kfree(prog);
2288}
2289
2290static int __tun_set_ebpf(struct tun_struct *tun,
2291 struct tun_prog __rcu **prog_p,
2292 struct bpf_prog *prog)
2293{
2294 struct tun_prog *old, *new = NULL;
2295
2296 if (prog) {
2297 new = kmalloc(sizeof(*new), GFP_KERNEL);
2298 if (!new)
2299 return -ENOMEM;
2300 new->prog = prog;
2301 }
2302
2303 spin_lock_bh(&tun->lock);
2304 old = rcu_dereference_protected(*prog_p,
2305 lockdep_is_held(&tun->lock));
2306 rcu_assign_pointer(*prog_p, new);
2307 spin_unlock_bh(&tun->lock);
2308
2309 if (old)
2310 call_rcu(&old->rcu, tun_prog_free);
2311
2312 return 0;
2313}
2314
2315static void tun_free_netdev(struct net_device *dev)
2316{
2317 struct tun_struct *tun = netdev_priv(dev);
2318
2319 BUG_ON(!(list_empty(&tun->disabled)));
2320
2321 free_percpu(dev->tstats);
2322 tun_flow_uninit(tun);
2323 security_tun_dev_free_security(tun->security);
2324 __tun_set_ebpf(tun, &tun->steering_prog, NULL);
2325 __tun_set_ebpf(tun, &tun->filter_prog, NULL);
2326}
2327
2328static void tun_setup(struct net_device *dev)
2329{
2330 struct tun_struct *tun = netdev_priv(dev);
2331
2332 tun->owner = INVALID_UID;
2333 tun->group = INVALID_GID;
2334 tun_default_link_ksettings(dev, &tun->link_ksettings);
2335
2336 dev->ethtool_ops = &tun_ethtool_ops;
2337 dev->needs_free_netdev = true;
2338 dev->priv_destructor = tun_free_netdev;
2339 /* We prefer our own queue length */
2340 dev->tx_queue_len = TUN_READQ_SIZE;
2341}
2342
2343/* Trivial set of netlink ops to allow deleting tun or tap
2344 * device with netlink.
2345 */
2346static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
2347 struct netlink_ext_ack *extack)
2348{
2349 NL_SET_ERR_MSG(extack,
2350 "tun/tap creation via rtnetlink is not supported.");
2351 return -EOPNOTSUPP;
2352}
2353
2354static size_t tun_get_size(const struct net_device *dev)
2355{
2356 BUILD_BUG_ON(sizeof(u32) != sizeof(uid_t));
2357 BUILD_BUG_ON(sizeof(u32) != sizeof(gid_t));
2358
2359 return nla_total_size(sizeof(uid_t)) + /* OWNER */
2360 nla_total_size(sizeof(gid_t)) + /* GROUP */
2361 nla_total_size(sizeof(u8)) + /* TYPE */
2362 nla_total_size(sizeof(u8)) + /* PI */
2363 nla_total_size(sizeof(u8)) + /* VNET_HDR */
2364 nla_total_size(sizeof(u8)) + /* PERSIST */
2365 nla_total_size(sizeof(u8)) + /* MULTI_QUEUE */
2366 nla_total_size(sizeof(u32)) + /* NUM_QUEUES */
2367 nla_total_size(sizeof(u32)) + /* NUM_DISABLED_QUEUES */
2368 0;
2369}
2370
2371static int tun_fill_info(struct sk_buff *skb, const struct net_device *dev)
2372{
2373 struct tun_struct *tun = netdev_priv(dev);
2374
2375 if (nla_put_u8(skb, IFLA_TUN_TYPE, tun->flags & TUN_TYPE_MASK))
2376 goto nla_put_failure;
2377 if (uid_valid(tun->owner) &&
2378 nla_put_u32(skb, IFLA_TUN_OWNER,
2379 from_kuid_munged(current_user_ns(), tun->owner)))
2380 goto nla_put_failure;
2381 if (gid_valid(tun->group) &&
2382 nla_put_u32(skb, IFLA_TUN_GROUP,
2383 from_kgid_munged(current_user_ns(), tun->group)))
2384 goto nla_put_failure;
2385 if (nla_put_u8(skb, IFLA_TUN_PI, !(tun->flags & IFF_NO_PI)))
2386 goto nla_put_failure;
2387 if (nla_put_u8(skb, IFLA_TUN_VNET_HDR, !!(tun->flags & IFF_VNET_HDR)))
2388 goto nla_put_failure;
2389 if (nla_put_u8(skb, IFLA_TUN_PERSIST, !!(tun->flags & IFF_PERSIST)))
2390 goto nla_put_failure;
2391 if (nla_put_u8(skb, IFLA_TUN_MULTI_QUEUE,
2392 !!(tun->flags & IFF_MULTI_QUEUE)))
2393 goto nla_put_failure;
2394 if (tun->flags & IFF_MULTI_QUEUE) {
2395 if (nla_put_u32(skb, IFLA_TUN_NUM_QUEUES, tun->numqueues))
2396 goto nla_put_failure;
2397 if (nla_put_u32(skb, IFLA_TUN_NUM_DISABLED_QUEUES,
2398 tun->numdisabled))
2399 goto nla_put_failure;
2400 }
2401
2402 return 0;
2403
2404nla_put_failure:
2405 return -EMSGSIZE;
2406}
2407
2408static struct rtnl_link_ops tun_link_ops __read_mostly = {
2409 .kind = DRV_NAME,
2410 .priv_size = sizeof(struct tun_struct),
2411 .setup = tun_setup,
2412 .validate = tun_validate,
2413 .get_size = tun_get_size,
2414 .fill_info = tun_fill_info,
2415};
2416
2417static void tun_sock_write_space(struct sock *sk)
2418{
2419 struct tun_file *tfile;
2420 wait_queue_head_t *wqueue;
2421
2422 if (!sock_writeable(sk))
2423 return;
2424
2425 if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
2426 return;
2427
2428 wqueue = sk_sleep(sk);
2429 if (wqueue && waitqueue_active(wqueue))
2430 wake_up_interruptible_sync_poll(wqueue, EPOLLOUT |
2431 EPOLLWRNORM | EPOLLWRBAND);
2432
2433 tfile = container_of(sk, struct tun_file, sk);
2434 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
2435}
2436
2437static void tun_put_page(struct tun_page *tpage)
2438{
2439 if (tpage->page)
2440 __page_frag_cache_drain(tpage->page, tpage->count);
2441}
2442
2443static int tun_xdp_one(struct tun_struct *tun,
2444 struct tun_file *tfile,
2445 struct xdp_buff *xdp, int *flush,
2446 struct tun_page *tpage)
2447{
2448 unsigned int datasize = xdp->data_end - xdp->data;
2449 struct tun_xdp_hdr *hdr = xdp->data_hard_start;
2450 struct virtio_net_hdr *gso = &hdr->gso;
2451 struct bpf_prog *xdp_prog;
2452 struct sk_buff *skb = NULL;
2453 struct sk_buff_head *queue;
2454 u32 rxhash = 0, act;
2455 int buflen = hdr->buflen;
2456 int ret = 0;
2457 bool skb_xdp = false;
2458 struct page *page;
2459
2460 xdp_prog = rcu_dereference(tun->xdp_prog);
2461 if (xdp_prog) {
2462 if (gso->gso_type) {
2463 skb_xdp = true;
2464 goto build;
2465 }
2466
2467 xdp_init_buff(xdp, buflen, &tfile->xdp_rxq);
2468 xdp_set_data_meta_invalid(xdp);
2469
2470 act = bpf_prog_run_xdp(xdp_prog, xdp);
2471 ret = tun_xdp_act(tun, xdp_prog, xdp, act);
2472 if (ret < 0) {
2473 put_page(virt_to_head_page(xdp->data));
2474 return ret;
2475 }
2476
2477 switch (ret) {
2478 case XDP_REDIRECT:
2479 *flush = true;
2480 fallthrough;
2481 case XDP_TX:
2482 return 0;
2483 case XDP_PASS:
2484 break;
2485 default:
2486 page = virt_to_head_page(xdp->data);
2487 if (tpage->page == page) {
2488 ++tpage->count;
2489 } else {
2490 tun_put_page(tpage);
2491 tpage->page = page;
2492 tpage->count = 1;
2493 }
2494 return 0;
2495 }
2496 }
2497
2498build:
2499 skb = build_skb(xdp->data_hard_start, buflen);
2500 if (!skb) {
2501 ret = -ENOMEM;
2502 goto out;
2503 }
2504
2505 skb_reserve(skb, xdp->data - xdp->data_hard_start);
2506 skb_put(skb, xdp->data_end - xdp->data);
2507
2508 if (virtio_net_hdr_to_skb(skb, gso, tun_is_little_endian(tun))) {
2509 atomic_long_inc(&tun->rx_frame_errors);
2510 kfree_skb(skb);
2511 ret = -EINVAL;
2512 goto out;
2513 }
2514
2515 skb->protocol = eth_type_trans(skb, tun->dev);
2516 skb_reset_network_header(skb);
2517 skb_probe_transport_header(skb);
2518 skb_record_rx_queue(skb, tfile->queue_index);
2519
2520 if (skb_xdp) {
2521 ret = do_xdp_generic(xdp_prog, skb);
2522 if (ret != XDP_PASS) {
2523 ret = 0;
2524 goto out;
2525 }
2526 }
2527
2528 if (!rcu_dereference(tun->steering_prog) && tun->numqueues > 1 &&
2529 !tfile->detached)
2530 rxhash = __skb_get_hash_symmetric(skb);
2531
2532 if (tfile->napi_enabled) {
2533 queue = &tfile->sk.sk_write_queue;
2534 spin_lock(&queue->lock);
2535
2536 if (unlikely(tfile->detached)) {
2537 spin_unlock(&queue->lock);
2538 kfree_skb(skb);
2539 return -EBUSY;
2540 }
2541
2542 __skb_queue_tail(queue, skb);
2543 spin_unlock(&queue->lock);
2544 ret = 1;
2545 } else {
2546 netif_receive_skb(skb);
2547 ret = 0;
2548 }
2549
2550 /* No need to disable preemption here since this function is
2551 * always called with bh disabled
2552 */
2553 dev_sw_netstats_rx_add(tun->dev, datasize);
2554
2555 if (rxhash)
2556 tun_flow_update(tun, rxhash, tfile);
2557
2558out:
2559 return ret;
2560}
2561
2562static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
2563{
2564 int ret, i;
2565 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2566 struct tun_struct *tun = tun_get(tfile);
2567 struct tun_msg_ctl *ctl = m->msg_control;
2568 struct xdp_buff *xdp;
2569
2570 if (!tun)
2571 return -EBADFD;
2572
2573 if (m->msg_controllen == sizeof(struct tun_msg_ctl) &&
2574 ctl && ctl->type == TUN_MSG_PTR) {
2575 struct tun_page tpage;
2576 int n = ctl->num;
2577 int flush = 0, queued = 0;
2578
2579 memset(&tpage, 0, sizeof(tpage));
2580
2581 local_bh_disable();
2582 rcu_read_lock();
2583
2584 for (i = 0; i < n; i++) {
2585 xdp = &((struct xdp_buff *)ctl->ptr)[i];
2586 ret = tun_xdp_one(tun, tfile, xdp, &flush, &tpage);
2587 if (ret > 0)
2588 queued += ret;
2589 }
2590
2591 if (flush)
2592 xdp_do_flush();
2593
2594 if (tfile->napi_enabled && queued > 0)
2595 napi_schedule(&tfile->napi);
2596
2597 rcu_read_unlock();
2598 local_bh_enable();
2599
2600 tun_put_page(&tpage);
2601
2602 ret = total_len;
2603 goto out;
2604 }
2605
2606 ret = tun_get_user(tun, tfile, ctl ? ctl->ptr : NULL, &m->msg_iter,
2607 m->msg_flags & MSG_DONTWAIT,
2608 m->msg_flags & MSG_MORE);
2609out:
2610 tun_put(tun);
2611 return ret;
2612}
2613
2614static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
2615 int flags)
2616{
2617 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2618 struct tun_struct *tun = tun_get(tfile);
2619 void *ptr = m->msg_control;
2620 int ret;
2621
2622 if (!tun) {
2623 ret = -EBADFD;
2624 goto out_free;
2625 }
2626
2627 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
2628 ret = -EINVAL;
2629 goto out_put_tun;
2630 }
2631 if (flags & MSG_ERRQUEUE) {
2632 ret = sock_recv_errqueue(sock->sk, m, total_len,
2633 SOL_PACKET, TUN_TX_TIMESTAMP);
2634 goto out;
2635 }
2636 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT, ptr);
2637 if (ret > (ssize_t)total_len) {
2638 m->msg_flags |= MSG_TRUNC;
2639 ret = flags & MSG_TRUNC ? ret : total_len;
2640 }
2641out:
2642 tun_put(tun);
2643 return ret;
2644
2645out_put_tun:
2646 tun_put(tun);
2647out_free:
2648 tun_ptr_free(ptr);
2649 return ret;
2650}
2651
2652static int tun_ptr_peek_len(void *ptr)
2653{
2654 if (likely(ptr)) {
2655 if (tun_is_xdp_frame(ptr)) {
2656 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2657
2658 return xdpf->len;
2659 }
2660 return __skb_array_len_with_tag(ptr);
2661 } else {
2662 return 0;
2663 }
2664}
2665
2666static int tun_peek_len(struct socket *sock)
2667{
2668 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2669 struct tun_struct *tun;
2670 int ret = 0;
2671
2672 tun = tun_get(tfile);
2673 if (!tun)
2674 return 0;
2675
2676 ret = PTR_RING_PEEK_CALL(&tfile->tx_ring, tun_ptr_peek_len);
2677 tun_put(tun);
2678
2679 return ret;
2680}
2681
2682/* Ops structure to mimic raw sockets with tun */
2683static const struct proto_ops tun_socket_ops = {
2684 .peek_len = tun_peek_len,
2685 .sendmsg = tun_sendmsg,
2686 .recvmsg = tun_recvmsg,
2687};
2688
2689static struct proto tun_proto = {
2690 .name = "tun",
2691 .owner = THIS_MODULE,
2692 .obj_size = sizeof(struct tun_file),
2693};
2694
2695static int tun_flags(struct tun_struct *tun)
2696{
2697 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
2698}
2699
2700static ssize_t tun_flags_show(struct device *dev, struct device_attribute *attr,
2701 char *buf)
2702{
2703 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2704 return sysfs_emit(buf, "0x%x\n", tun_flags(tun));
2705}
2706
2707static ssize_t owner_show(struct device *dev, struct device_attribute *attr,
2708 char *buf)
2709{
2710 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2711 return uid_valid(tun->owner)?
2712 sysfs_emit(buf, "%u\n",
2713 from_kuid_munged(current_user_ns(), tun->owner)) :
2714 sysfs_emit(buf, "-1\n");
2715}
2716
2717static ssize_t group_show(struct device *dev, struct device_attribute *attr,
2718 char *buf)
2719{
2720 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2721 return gid_valid(tun->group) ?
2722 sysfs_emit(buf, "%u\n",
2723 from_kgid_munged(current_user_ns(), tun->group)) :
2724 sysfs_emit(buf, "-1\n");
2725}
2726
2727static DEVICE_ATTR_RO(tun_flags);
2728static DEVICE_ATTR_RO(owner);
2729static DEVICE_ATTR_RO(group);
2730
2731static struct attribute *tun_dev_attrs[] = {
2732 &dev_attr_tun_flags.attr,
2733 &dev_attr_owner.attr,
2734 &dev_attr_group.attr,
2735 NULL
2736};
2737
2738static const struct attribute_group tun_attr_group = {
2739 .attrs = tun_dev_attrs
2740};
2741
2742static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
2743{
2744 struct tun_struct *tun;
2745 struct tun_file *tfile = file->private_data;
2746 struct net_device *dev;
2747 int err;
2748
2749 if (tfile->detached)
2750 return -EINVAL;
2751
2752 if ((ifr->ifr_flags & IFF_NAPI_FRAGS)) {
2753 if (!capable(CAP_NET_ADMIN))
2754 return -EPERM;
2755
2756 if (!(ifr->ifr_flags & IFF_NAPI) ||
2757 (ifr->ifr_flags & TUN_TYPE_MASK) != IFF_TAP)
2758 return -EINVAL;
2759 }
2760
2761 dev = __dev_get_by_name(net, ifr->ifr_name);
2762 if (dev) {
2763 if (ifr->ifr_flags & IFF_TUN_EXCL)
2764 return -EBUSY;
2765 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
2766 tun = netdev_priv(dev);
2767 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
2768 tun = netdev_priv(dev);
2769 else
2770 return -EINVAL;
2771
2772 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
2773 !!(tun->flags & IFF_MULTI_QUEUE))
2774 return -EINVAL;
2775
2776 if (tun_not_capable(tun))
2777 return -EPERM;
2778 err = security_tun_dev_open(tun->security);
2779 if (err < 0)
2780 return err;
2781
2782 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER,
2783 ifr->ifr_flags & IFF_NAPI,
2784 ifr->ifr_flags & IFF_NAPI_FRAGS, true);
2785 if (err < 0)
2786 return err;
2787
2788 if (tun->flags & IFF_MULTI_QUEUE &&
2789 (tun->numqueues + tun->numdisabled > 1)) {
2790 /* One or more queue has already been attached, no need
2791 * to initialize the device again.
2792 */
2793 netdev_state_change(dev);
2794 return 0;
2795 }
2796
2797 tun->flags = (tun->flags & ~TUN_FEATURES) |
2798 (ifr->ifr_flags & TUN_FEATURES);
2799
2800 netdev_state_change(dev);
2801 } else {
2802 char *name;
2803 unsigned long flags = 0;
2804 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
2805 MAX_TAP_QUEUES : 1;
2806
2807 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2808 return -EPERM;
2809 err = security_tun_dev_create();
2810 if (err < 0)
2811 return err;
2812
2813 /* Set dev type */
2814 if (ifr->ifr_flags & IFF_TUN) {
2815 /* TUN device */
2816 flags |= IFF_TUN;
2817 name = "tun%d";
2818 } else if (ifr->ifr_flags & IFF_TAP) {
2819 /* TAP device */
2820 flags |= IFF_TAP;
2821 name = "tap%d";
2822 } else
2823 return -EINVAL;
2824
2825 if (*ifr->ifr_name)
2826 name = ifr->ifr_name;
2827
2828 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
2829 NET_NAME_UNKNOWN, tun_setup, queues,
2830 queues);
2831
2832 if (!dev)
2833 return -ENOMEM;
2834
2835 dev_net_set(dev, net);
2836 dev->rtnl_link_ops = &tun_link_ops;
2837 dev->ifindex = tfile->ifindex;
2838 dev->sysfs_groups[0] = &tun_attr_group;
2839
2840 tun = netdev_priv(dev);
2841 tun->dev = dev;
2842 tun->flags = flags;
2843 tun->txflt.count = 0;
2844 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
2845
2846 tun->align = NET_SKB_PAD;
2847 tun->filter_attached = false;
2848 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
2849 tun->rx_batched = 0;
2850 RCU_INIT_POINTER(tun->steering_prog, NULL);
2851
2852 tun->ifr = ifr;
2853 tun->file = file;
2854
2855 tun_net_initialize(dev);
2856
2857 err = register_netdevice(tun->dev);
2858 if (err < 0) {
2859 free_netdev(dev);
2860 return err;
2861 }
2862 /* free_netdev() won't check refcnt, to avoid race
2863 * with dev_put() we need publish tun after registration.
2864 */
2865 rcu_assign_pointer(tfile->tun, tun);
2866 }
2867
2868 if (ifr->ifr_flags & IFF_NO_CARRIER)
2869 netif_carrier_off(tun->dev);
2870 else
2871 netif_carrier_on(tun->dev);
2872
2873 /* Make sure persistent devices do not get stuck in
2874 * xoff state.
2875 */
2876 if (netif_running(tun->dev))
2877 netif_tx_wake_all_queues(tun->dev);
2878
2879 strcpy(ifr->ifr_name, tun->dev->name);
2880 return 0;
2881}
2882
2883static void tun_get_iff(struct tun_struct *tun, struct ifreq *ifr)
2884{
2885 strcpy(ifr->ifr_name, tun->dev->name);
2886
2887 ifr->ifr_flags = tun_flags(tun);
2888
2889}
2890
2891/* This is like a cut-down ethtool ops, except done via tun fd so no
2892 * privs required. */
2893static int set_offload(struct tun_struct *tun, unsigned long arg)
2894{
2895 netdev_features_t features = 0;
2896
2897 if (arg & TUN_F_CSUM) {
2898 features |= NETIF_F_HW_CSUM;
2899 arg &= ~TUN_F_CSUM;
2900
2901 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
2902 if (arg & TUN_F_TSO_ECN) {
2903 features |= NETIF_F_TSO_ECN;
2904 arg &= ~TUN_F_TSO_ECN;
2905 }
2906 if (arg & TUN_F_TSO4)
2907 features |= NETIF_F_TSO;
2908 if (arg & TUN_F_TSO6)
2909 features |= NETIF_F_TSO6;
2910 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
2911 }
2912
2913 arg &= ~TUN_F_UFO;
2914
2915 /* TODO: for now USO4 and USO6 should work simultaneously */
2916 if (arg & TUN_F_USO4 && arg & TUN_F_USO6) {
2917 features |= NETIF_F_GSO_UDP_L4;
2918 arg &= ~(TUN_F_USO4 | TUN_F_USO6);
2919 }
2920 }
2921
2922 /* This gives the user a way to test for new features in future by
2923 * trying to set them. */
2924 if (arg)
2925 return -EINVAL;
2926
2927 tun->set_features = features;
2928 tun->dev->wanted_features &= ~TUN_USER_FEATURES;
2929 tun->dev->wanted_features |= features;
2930 netdev_update_features(tun->dev);
2931
2932 return 0;
2933}
2934
2935static void tun_detach_filter(struct tun_struct *tun, int n)
2936{
2937 int i;
2938 struct tun_file *tfile;
2939
2940 for (i = 0; i < n; i++) {
2941 tfile = rtnl_dereference(tun->tfiles[i]);
2942 lock_sock(tfile->socket.sk);
2943 sk_detach_filter(tfile->socket.sk);
2944 release_sock(tfile->socket.sk);
2945 }
2946
2947 tun->filter_attached = false;
2948}
2949
2950static int tun_attach_filter(struct tun_struct *tun)
2951{
2952 int i, ret = 0;
2953 struct tun_file *tfile;
2954
2955 for (i = 0; i < tun->numqueues; i++) {
2956 tfile = rtnl_dereference(tun->tfiles[i]);
2957 lock_sock(tfile->socket.sk);
2958 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
2959 release_sock(tfile->socket.sk);
2960 if (ret) {
2961 tun_detach_filter(tun, i);
2962 return ret;
2963 }
2964 }
2965
2966 tun->filter_attached = true;
2967 return ret;
2968}
2969
2970static void tun_set_sndbuf(struct tun_struct *tun)
2971{
2972 struct tun_file *tfile;
2973 int i;
2974
2975 for (i = 0; i < tun->numqueues; i++) {
2976 tfile = rtnl_dereference(tun->tfiles[i]);
2977 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
2978 }
2979}
2980
2981static int tun_set_queue(struct file *file, struct ifreq *ifr)
2982{
2983 struct tun_file *tfile = file->private_data;
2984 struct tun_struct *tun;
2985 int ret = 0;
2986
2987 rtnl_lock();
2988
2989 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
2990 tun = tfile->detached;
2991 if (!tun) {
2992 ret = -EINVAL;
2993 goto unlock;
2994 }
2995 ret = security_tun_dev_attach_queue(tun->security);
2996 if (ret < 0)
2997 goto unlock;
2998 ret = tun_attach(tun, file, false, tun->flags & IFF_NAPI,
2999 tun->flags & IFF_NAPI_FRAGS, true);
3000 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
3001 tun = rtnl_dereference(tfile->tun);
3002 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
3003 ret = -EINVAL;
3004 else
3005 __tun_detach(tfile, false);
3006 } else
3007 ret = -EINVAL;
3008
3009 if (ret >= 0)
3010 netdev_state_change(tun->dev);
3011
3012unlock:
3013 rtnl_unlock();
3014 return ret;
3015}
3016
3017static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog __rcu **prog_p,
3018 void __user *data)
3019{
3020 struct bpf_prog *prog;
3021 int fd;
3022
3023 if (copy_from_user(&fd, data, sizeof(fd)))
3024 return -EFAULT;
3025
3026 if (fd == -1) {
3027 prog = NULL;
3028 } else {
3029 prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
3030 if (IS_ERR(prog))
3031 return PTR_ERR(prog);
3032 }
3033
3034 return __tun_set_ebpf(tun, prog_p, prog);
3035}
3036
3037/* Return correct value for tun->dev->addr_len based on tun->dev->type. */
3038static unsigned char tun_get_addr_len(unsigned short type)
3039{
3040 switch (type) {
3041 case ARPHRD_IP6GRE:
3042 case ARPHRD_TUNNEL6:
3043 return sizeof(struct in6_addr);
3044 case ARPHRD_IPGRE:
3045 case ARPHRD_TUNNEL:
3046 case ARPHRD_SIT:
3047 return 4;
3048 case ARPHRD_ETHER:
3049 return ETH_ALEN;
3050 case ARPHRD_IEEE802154:
3051 case ARPHRD_IEEE802154_MONITOR:
3052 return IEEE802154_EXTENDED_ADDR_LEN;
3053 case ARPHRD_PHONET_PIPE:
3054 case ARPHRD_PPP:
3055 case ARPHRD_NONE:
3056 return 0;
3057 case ARPHRD_6LOWPAN:
3058 return EUI64_ADDR_LEN;
3059 case ARPHRD_FDDI:
3060 return FDDI_K_ALEN;
3061 case ARPHRD_HIPPI:
3062 return HIPPI_ALEN;
3063 case ARPHRD_IEEE802:
3064 return FC_ALEN;
3065 case ARPHRD_ROSE:
3066 return ROSE_ADDR_LEN;
3067 case ARPHRD_NETROM:
3068 return AX25_ADDR_LEN;
3069 case ARPHRD_LOCALTLK:
3070 return LTALK_ALEN;
3071 default:
3072 return 0;
3073 }
3074}
3075
3076static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
3077 unsigned long arg, int ifreq_len)
3078{
3079 struct tun_file *tfile = file->private_data;
3080 struct net *net = sock_net(&tfile->sk);
3081 struct tun_struct *tun;
3082 void __user* argp = (void __user*)arg;
3083 unsigned int carrier;
3084 struct ifreq ifr;
3085 kuid_t owner;
3086 kgid_t group;
3087 int ifindex;
3088 int sndbuf;
3089 int vnet_hdr_sz;
3090 int le;
3091 int ret;
3092 bool do_notify = false;
3093
3094 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE ||
3095 (_IOC_TYPE(cmd) == SOCK_IOC_TYPE && cmd != SIOCGSKNS)) {
3096 if (copy_from_user(&ifr, argp, ifreq_len))
3097 return -EFAULT;
3098 } else {
3099 memset(&ifr, 0, sizeof(ifr));
3100 }
3101 if (cmd == TUNGETFEATURES) {
3102 /* Currently this just means: "what IFF flags are valid?".
3103 * This is needed because we never checked for invalid flags on
3104 * TUNSETIFF.
3105 */
3106 return put_user(IFF_TUN | IFF_TAP | IFF_NO_CARRIER |
3107 TUN_FEATURES, (unsigned int __user*)argp);
3108 } else if (cmd == TUNSETQUEUE) {
3109 return tun_set_queue(file, &ifr);
3110 } else if (cmd == SIOCGSKNS) {
3111 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3112 return -EPERM;
3113 return open_related_ns(&net->ns, get_net_ns);
3114 }
3115
3116 rtnl_lock();
3117
3118 tun = tun_get(tfile);
3119 if (cmd == TUNSETIFF) {
3120 ret = -EEXIST;
3121 if (tun)
3122 goto unlock;
3123
3124 ifr.ifr_name[IFNAMSIZ-1] = '\0';
3125
3126 ret = tun_set_iff(net, file, &ifr);
3127
3128 if (ret)
3129 goto unlock;
3130
3131 if (copy_to_user(argp, &ifr, ifreq_len))
3132 ret = -EFAULT;
3133 goto unlock;
3134 }
3135 if (cmd == TUNSETIFINDEX) {
3136 ret = -EPERM;
3137 if (tun)
3138 goto unlock;
3139
3140 ret = -EFAULT;
3141 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
3142 goto unlock;
3143 ret = -EINVAL;
3144 if (ifindex < 0)
3145 goto unlock;
3146 ret = 0;
3147 tfile->ifindex = ifindex;
3148 goto unlock;
3149 }
3150
3151 ret = -EBADFD;
3152 if (!tun)
3153 goto unlock;
3154
3155 netif_info(tun, drv, tun->dev, "tun_chr_ioctl cmd %u\n", cmd);
3156
3157 net = dev_net(tun->dev);
3158 ret = 0;
3159 switch (cmd) {
3160 case TUNGETIFF:
3161 tun_get_iff(tun, &ifr);
3162
3163 if (tfile->detached)
3164 ifr.ifr_flags |= IFF_DETACH_QUEUE;
3165 if (!tfile->socket.sk->sk_filter)
3166 ifr.ifr_flags |= IFF_NOFILTER;
3167
3168 if (copy_to_user(argp, &ifr, ifreq_len))
3169 ret = -EFAULT;
3170 break;
3171
3172 case TUNSETNOCSUM:
3173 /* Disable/Enable checksum */
3174
3175 /* [unimplemented] */
3176 netif_info(tun, drv, tun->dev, "ignored: set checksum %s\n",
3177 arg ? "disabled" : "enabled");
3178 break;
3179
3180 case TUNSETPERSIST:
3181 /* Disable/Enable persist mode. Keep an extra reference to the
3182 * module to prevent the module being unprobed.
3183 */
3184 if (arg && !(tun->flags & IFF_PERSIST)) {
3185 tun->flags |= IFF_PERSIST;
3186 __module_get(THIS_MODULE);
3187 do_notify = true;
3188 }
3189 if (!arg && (tun->flags & IFF_PERSIST)) {
3190 tun->flags &= ~IFF_PERSIST;
3191 module_put(THIS_MODULE);
3192 do_notify = true;
3193 }
3194
3195 netif_info(tun, drv, tun->dev, "persist %s\n",
3196 arg ? "enabled" : "disabled");
3197 break;
3198
3199 case TUNSETOWNER:
3200 /* Set owner of the device */
3201 owner = make_kuid(current_user_ns(), arg);
3202 if (!uid_valid(owner)) {
3203 ret = -EINVAL;
3204 break;
3205 }
3206 tun->owner = owner;
3207 do_notify = true;
3208 netif_info(tun, drv, tun->dev, "owner set to %u\n",
3209 from_kuid(&init_user_ns, tun->owner));
3210 break;
3211
3212 case TUNSETGROUP:
3213 /* Set group of the device */
3214 group = make_kgid(current_user_ns(), arg);
3215 if (!gid_valid(group)) {
3216 ret = -EINVAL;
3217 break;
3218 }
3219 tun->group = group;
3220 do_notify = true;
3221 netif_info(tun, drv, tun->dev, "group set to %u\n",
3222 from_kgid(&init_user_ns, tun->group));
3223 break;
3224
3225 case TUNSETLINK:
3226 /* Only allow setting the type when the interface is down */
3227 if (tun->dev->flags & IFF_UP) {
3228 netif_info(tun, drv, tun->dev,
3229 "Linktype set failed because interface is up\n");
3230 ret = -EBUSY;
3231 } else {
3232 ret = call_netdevice_notifiers(NETDEV_PRE_TYPE_CHANGE,
3233 tun->dev);
3234 ret = notifier_to_errno(ret);
3235 if (ret) {
3236 netif_info(tun, drv, tun->dev,
3237 "Refused to change device type\n");
3238 break;
3239 }
3240 tun->dev->type = (int) arg;
3241 tun->dev->addr_len = tun_get_addr_len(tun->dev->type);
3242 netif_info(tun, drv, tun->dev, "linktype set to %d\n",
3243 tun->dev->type);
3244 call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE,
3245 tun->dev);
3246 }
3247 break;
3248
3249 case TUNSETDEBUG:
3250 tun->msg_enable = (u32)arg;
3251 break;
3252
3253 case TUNSETOFFLOAD:
3254 ret = set_offload(tun, arg);
3255 break;
3256
3257 case TUNSETTXFILTER:
3258 /* Can be set only for TAPs */
3259 ret = -EINVAL;
3260 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3261 break;
3262 ret = update_filter(&tun->txflt, (void __user *)arg);
3263 break;
3264
3265 case SIOCGIFHWADDR:
3266 /* Get hw address */
3267 dev_get_mac_address(&ifr.ifr_hwaddr, net, tun->dev->name);
3268 if (copy_to_user(argp, &ifr, ifreq_len))
3269 ret = -EFAULT;
3270 break;
3271
3272 case SIOCSIFHWADDR:
3273 /* Set hw address */
3274 ret = dev_set_mac_address_user(tun->dev, &ifr.ifr_hwaddr, NULL);
3275 break;
3276
3277 case TUNGETSNDBUF:
3278 sndbuf = tfile->socket.sk->sk_sndbuf;
3279 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
3280 ret = -EFAULT;
3281 break;
3282
3283 case TUNSETSNDBUF:
3284 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
3285 ret = -EFAULT;
3286 break;
3287 }
3288 if (sndbuf <= 0) {
3289 ret = -EINVAL;
3290 break;
3291 }
3292
3293 tun->sndbuf = sndbuf;
3294 tun_set_sndbuf(tun);
3295 break;
3296
3297 case TUNGETVNETHDRSZ:
3298 vnet_hdr_sz = tun->vnet_hdr_sz;
3299 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
3300 ret = -EFAULT;
3301 break;
3302
3303 case TUNSETVNETHDRSZ:
3304 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
3305 ret = -EFAULT;
3306 break;
3307 }
3308 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
3309 ret = -EINVAL;
3310 break;
3311 }
3312
3313 tun->vnet_hdr_sz = vnet_hdr_sz;
3314 break;
3315
3316 case TUNGETVNETLE:
3317 le = !!(tun->flags & TUN_VNET_LE);
3318 if (put_user(le, (int __user *)argp))
3319 ret = -EFAULT;
3320 break;
3321
3322 case TUNSETVNETLE:
3323 if (get_user(le, (int __user *)argp)) {
3324 ret = -EFAULT;
3325 break;
3326 }
3327 if (le)
3328 tun->flags |= TUN_VNET_LE;
3329 else
3330 tun->flags &= ~TUN_VNET_LE;
3331 break;
3332
3333 case TUNGETVNETBE:
3334 ret = tun_get_vnet_be(tun, argp);
3335 break;
3336
3337 case TUNSETVNETBE:
3338 ret = tun_set_vnet_be(tun, argp);
3339 break;
3340
3341 case TUNATTACHFILTER:
3342 /* Can be set only for TAPs */
3343 ret = -EINVAL;
3344 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3345 break;
3346 ret = -EFAULT;
3347 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
3348 break;
3349
3350 ret = tun_attach_filter(tun);
3351 break;
3352
3353 case TUNDETACHFILTER:
3354 /* Can be set only for TAPs */
3355 ret = -EINVAL;
3356 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3357 break;
3358 ret = 0;
3359 tun_detach_filter(tun, tun->numqueues);
3360 break;
3361
3362 case TUNGETFILTER:
3363 ret = -EINVAL;
3364 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3365 break;
3366 ret = -EFAULT;
3367 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
3368 break;
3369 ret = 0;
3370 break;
3371
3372 case TUNSETSTEERINGEBPF:
3373 ret = tun_set_ebpf(tun, &tun->steering_prog, argp);
3374 break;
3375
3376 case TUNSETFILTEREBPF:
3377 ret = tun_set_ebpf(tun, &tun->filter_prog, argp);
3378 break;
3379
3380 case TUNSETCARRIER:
3381 ret = -EFAULT;
3382 if (copy_from_user(&carrier, argp, sizeof(carrier)))
3383 goto unlock;
3384
3385 ret = tun_net_change_carrier(tun->dev, (bool)carrier);
3386 break;
3387
3388 case TUNGETDEVNETNS:
3389 ret = -EPERM;
3390 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3391 goto unlock;
3392 ret = open_related_ns(&net->ns, get_net_ns);
3393 break;
3394
3395 default:
3396 ret = -EINVAL;
3397 break;
3398 }
3399
3400 if (do_notify)
3401 netdev_state_change(tun->dev);
3402
3403unlock:
3404 rtnl_unlock();
3405 if (tun)
3406 tun_put(tun);
3407 return ret;
3408}
3409
3410static long tun_chr_ioctl(struct file *file,
3411 unsigned int cmd, unsigned long arg)
3412{
3413 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
3414}
3415
3416#ifdef CONFIG_COMPAT
3417static long tun_chr_compat_ioctl(struct file *file,
3418 unsigned int cmd, unsigned long arg)
3419{
3420 switch (cmd) {
3421 case TUNSETIFF:
3422 case TUNGETIFF:
3423 case TUNSETTXFILTER:
3424 case TUNGETSNDBUF:
3425 case TUNSETSNDBUF:
3426 case SIOCGIFHWADDR:
3427 case SIOCSIFHWADDR:
3428 arg = (unsigned long)compat_ptr(arg);
3429 break;
3430 default:
3431 arg = (compat_ulong_t)arg;
3432 break;
3433 }
3434
3435 /*
3436 * compat_ifreq is shorter than ifreq, so we must not access beyond
3437 * the end of that structure. All fields that are used in this
3438 * driver are compatible though, we don't need to convert the
3439 * contents.
3440 */
3441 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
3442}
3443#endif /* CONFIG_COMPAT */
3444
3445static int tun_chr_fasync(int fd, struct file *file, int on)
3446{
3447 struct tun_file *tfile = file->private_data;
3448 int ret;
3449
3450 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
3451 goto out;
3452
3453 if (on) {
3454 __f_setown(file, task_pid(current), PIDTYPE_TGID, 0);
3455 tfile->flags |= TUN_FASYNC;
3456 } else
3457 tfile->flags &= ~TUN_FASYNC;
3458 ret = 0;
3459out:
3460 return ret;
3461}
3462
3463static int tun_chr_open(struct inode *inode, struct file * file)
3464{
3465 struct net *net = current->nsproxy->net_ns;
3466 struct tun_file *tfile;
3467
3468 tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
3469 &tun_proto, 0);
3470 if (!tfile)
3471 return -ENOMEM;
3472 if (ptr_ring_init(&tfile->tx_ring, 0, GFP_KERNEL)) {
3473 sk_free(&tfile->sk);
3474 return -ENOMEM;
3475 }
3476
3477 mutex_init(&tfile->napi_mutex);
3478 RCU_INIT_POINTER(tfile->tun, NULL);
3479 tfile->flags = 0;
3480 tfile->ifindex = 0;
3481
3482 init_waitqueue_head(&tfile->socket.wq.wait);
3483
3484 tfile->socket.file = file;
3485 tfile->socket.ops = &tun_socket_ops;
3486
3487 sock_init_data_uid(&tfile->socket, &tfile->sk, current_fsuid());
3488
3489 tfile->sk.sk_write_space = tun_sock_write_space;
3490 tfile->sk.sk_sndbuf = INT_MAX;
3491
3492 file->private_data = tfile;
3493 INIT_LIST_HEAD(&tfile->next);
3494
3495 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
3496
3497 /* tun groks IOCB_NOWAIT just fine, mark it as such */
3498 file->f_mode |= FMODE_NOWAIT;
3499 return 0;
3500}
3501
3502static int tun_chr_close(struct inode *inode, struct file *file)
3503{
3504 struct tun_file *tfile = file->private_data;
3505
3506 tun_detach(tfile, true);
3507
3508 return 0;
3509}
3510
3511#ifdef CONFIG_PROC_FS
3512static void tun_chr_show_fdinfo(struct seq_file *m, struct file *file)
3513{
3514 struct tun_file *tfile = file->private_data;
3515 struct tun_struct *tun;
3516 struct ifreq ifr;
3517
3518 memset(&ifr, 0, sizeof(ifr));
3519
3520 rtnl_lock();
3521 tun = tun_get(tfile);
3522 if (tun)
3523 tun_get_iff(tun, &ifr);
3524 rtnl_unlock();
3525
3526 if (tun)
3527 tun_put(tun);
3528
3529 seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
3530}
3531#endif
3532
3533static const struct file_operations tun_fops = {
3534 .owner = THIS_MODULE,
3535 .llseek = no_llseek,
3536 .read_iter = tun_chr_read_iter,
3537 .write_iter = tun_chr_write_iter,
3538 .poll = tun_chr_poll,
3539 .unlocked_ioctl = tun_chr_ioctl,
3540#ifdef CONFIG_COMPAT
3541 .compat_ioctl = tun_chr_compat_ioctl,
3542#endif
3543 .open = tun_chr_open,
3544 .release = tun_chr_close,
3545 .fasync = tun_chr_fasync,
3546#ifdef CONFIG_PROC_FS
3547 .show_fdinfo = tun_chr_show_fdinfo,
3548#endif
3549};
3550
3551static struct miscdevice tun_miscdev = {
3552 .minor = TUN_MINOR,
3553 .name = "tun",
3554 .nodename = "net/tun",
3555 .fops = &tun_fops,
3556};
3557
3558/* ethtool interface */
3559
3560static void tun_default_link_ksettings(struct net_device *dev,
3561 struct ethtool_link_ksettings *cmd)
3562{
3563 ethtool_link_ksettings_zero_link_mode(cmd, supported);
3564 ethtool_link_ksettings_zero_link_mode(cmd, advertising);
3565 cmd->base.speed = SPEED_10000;
3566 cmd->base.duplex = DUPLEX_FULL;
3567 cmd->base.port = PORT_TP;
3568 cmd->base.phy_address = 0;
3569 cmd->base.autoneg = AUTONEG_DISABLE;
3570}
3571
3572static int tun_get_link_ksettings(struct net_device *dev,
3573 struct ethtool_link_ksettings *cmd)
3574{
3575 struct tun_struct *tun = netdev_priv(dev);
3576
3577 memcpy(cmd, &tun->link_ksettings, sizeof(*cmd));
3578 return 0;
3579}
3580
3581static int tun_set_link_ksettings(struct net_device *dev,
3582 const struct ethtool_link_ksettings *cmd)
3583{
3584 struct tun_struct *tun = netdev_priv(dev);
3585
3586 memcpy(&tun->link_ksettings, cmd, sizeof(*cmd));
3587 return 0;
3588}
3589
3590static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
3591{
3592 struct tun_struct *tun = netdev_priv(dev);
3593
3594 strscpy(info->driver, DRV_NAME, sizeof(info->driver));
3595 strscpy(info->version, DRV_VERSION, sizeof(info->version));
3596
3597 switch (tun->flags & TUN_TYPE_MASK) {
3598 case IFF_TUN:
3599 strscpy(info->bus_info, "tun", sizeof(info->bus_info));
3600 break;
3601 case IFF_TAP:
3602 strscpy(info->bus_info, "tap", sizeof(info->bus_info));
3603 break;
3604 }
3605}
3606
3607static u32 tun_get_msglevel(struct net_device *dev)
3608{
3609 struct tun_struct *tun = netdev_priv(dev);
3610
3611 return tun->msg_enable;
3612}
3613
3614static void tun_set_msglevel(struct net_device *dev, u32 value)
3615{
3616 struct tun_struct *tun = netdev_priv(dev);
3617
3618 tun->msg_enable = value;
3619}
3620
3621static int tun_get_coalesce(struct net_device *dev,
3622 struct ethtool_coalesce *ec,
3623 struct kernel_ethtool_coalesce *kernel_coal,
3624 struct netlink_ext_ack *extack)
3625{
3626 struct tun_struct *tun = netdev_priv(dev);
3627
3628 ec->rx_max_coalesced_frames = tun->rx_batched;
3629
3630 return 0;
3631}
3632
3633static int tun_set_coalesce(struct net_device *dev,
3634 struct ethtool_coalesce *ec,
3635 struct kernel_ethtool_coalesce *kernel_coal,
3636 struct netlink_ext_ack *extack)
3637{
3638 struct tun_struct *tun = netdev_priv(dev);
3639
3640 if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT)
3641 tun->rx_batched = NAPI_POLL_WEIGHT;
3642 else
3643 tun->rx_batched = ec->rx_max_coalesced_frames;
3644
3645 return 0;
3646}
3647
3648static const struct ethtool_ops tun_ethtool_ops = {
3649 .supported_coalesce_params = ETHTOOL_COALESCE_RX_MAX_FRAMES,
3650 .get_drvinfo = tun_get_drvinfo,
3651 .get_msglevel = tun_get_msglevel,
3652 .set_msglevel = tun_set_msglevel,
3653 .get_link = ethtool_op_get_link,
3654 .get_ts_info = ethtool_op_get_ts_info,
3655 .get_coalesce = tun_get_coalesce,
3656 .set_coalesce = tun_set_coalesce,
3657 .get_link_ksettings = tun_get_link_ksettings,
3658 .set_link_ksettings = tun_set_link_ksettings,
3659};
3660
3661static int tun_queue_resize(struct tun_struct *tun)
3662{
3663 struct net_device *dev = tun->dev;
3664 struct tun_file *tfile;
3665 struct ptr_ring **rings;
3666 int n = tun->numqueues + tun->numdisabled;
3667 int ret, i;
3668
3669 rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL);
3670 if (!rings)
3671 return -ENOMEM;
3672
3673 for (i = 0; i < tun->numqueues; i++) {
3674 tfile = rtnl_dereference(tun->tfiles[i]);
3675 rings[i] = &tfile->tx_ring;
3676 }
3677 list_for_each_entry(tfile, &tun->disabled, next)
3678 rings[i++] = &tfile->tx_ring;
3679
3680 ret = ptr_ring_resize_multiple(rings, n,
3681 dev->tx_queue_len, GFP_KERNEL,
3682 tun_ptr_free);
3683
3684 kfree(rings);
3685 return ret;
3686}
3687
3688static int tun_device_event(struct notifier_block *unused,
3689 unsigned long event, void *ptr)
3690{
3691 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3692 struct tun_struct *tun = netdev_priv(dev);
3693 int i;
3694
3695 if (dev->rtnl_link_ops != &tun_link_ops)
3696 return NOTIFY_DONE;
3697
3698 switch (event) {
3699 case NETDEV_CHANGE_TX_QUEUE_LEN:
3700 if (tun_queue_resize(tun))
3701 return NOTIFY_BAD;
3702 break;
3703 case NETDEV_UP:
3704 for (i = 0; i < tun->numqueues; i++) {
3705 struct tun_file *tfile;
3706
3707 tfile = rtnl_dereference(tun->tfiles[i]);
3708 tfile->socket.sk->sk_write_space(tfile->socket.sk);
3709 }
3710 break;
3711 default:
3712 break;
3713 }
3714
3715 return NOTIFY_DONE;
3716}
3717
3718static struct notifier_block tun_notifier_block __read_mostly = {
3719 .notifier_call = tun_device_event,
3720};
3721
3722static int __init tun_init(void)
3723{
3724 int ret = 0;
3725
3726 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
3727
3728 ret = rtnl_link_register(&tun_link_ops);
3729 if (ret) {
3730 pr_err("Can't register link_ops\n");
3731 goto err_linkops;
3732 }
3733
3734 ret = misc_register(&tun_miscdev);
3735 if (ret) {
3736 pr_err("Can't register misc device %d\n", TUN_MINOR);
3737 goto err_misc;
3738 }
3739
3740 ret = register_netdevice_notifier(&tun_notifier_block);
3741 if (ret) {
3742 pr_err("Can't register netdevice notifier\n");
3743 goto err_notifier;
3744 }
3745
3746 return 0;
3747
3748err_notifier:
3749 misc_deregister(&tun_miscdev);
3750err_misc:
3751 rtnl_link_unregister(&tun_link_ops);
3752err_linkops:
3753 return ret;
3754}
3755
3756static void __exit tun_cleanup(void)
3757{
3758 misc_deregister(&tun_miscdev);
3759 rtnl_link_unregister(&tun_link_ops);
3760 unregister_netdevice_notifier(&tun_notifier_block);
3761}
3762
3763/* Get an underlying socket object from tun file. Returns error unless file is
3764 * attached to a device. The returned object works like a packet socket, it
3765 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
3766 * holding a reference to the file for as long as the socket is in use. */
3767struct socket *tun_get_socket(struct file *file)
3768{
3769 struct tun_file *tfile;
3770 if (file->f_op != &tun_fops)
3771 return ERR_PTR(-EINVAL);
3772 tfile = file->private_data;
3773 if (!tfile)
3774 return ERR_PTR(-EBADFD);
3775 return &tfile->socket;
3776}
3777EXPORT_SYMBOL_GPL(tun_get_socket);
3778
3779struct ptr_ring *tun_get_tx_ring(struct file *file)
3780{
3781 struct tun_file *tfile;
3782
3783 if (file->f_op != &tun_fops)
3784 return ERR_PTR(-EINVAL);
3785 tfile = file->private_data;
3786 if (!tfile)
3787 return ERR_PTR(-EBADFD);
3788 return &tfile->tx_ring;
3789}
3790EXPORT_SYMBOL_GPL(tun_get_tx_ring);
3791
3792module_init(tun_init);
3793module_exit(tun_cleanup);
3794MODULE_DESCRIPTION(DRV_DESCRIPTION);
3795MODULE_AUTHOR(DRV_COPYRIGHT);
3796MODULE_LICENSE("GPL");
3797MODULE_ALIAS_MISCDEV(TUN_MINOR);
3798MODULE_ALIAS("devname:net/tun");
1/*
2 * TUN - Universal TUN/TAP device driver.
3 * Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
16 */
17
18/*
19 * Changes:
20 *
21 * Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
22 * Add TUNSETLINK ioctl to set the link encapsulation
23 *
24 * Mark Smith <markzzzsmith@yahoo.com.au>
25 * Use eth_random_addr() for tap MAC address.
26 *
27 * Harald Roelle <harald.roelle@ifi.lmu.de> 2004/04/20
28 * Fixes in packet dropping, queue length setting and queue wakeup.
29 * Increased default tx queue length.
30 * Added ethtool API.
31 * Minor cleanups
32 *
33 * Daniel Podlejski <underley@underley.eu.org>
34 * Modifications for 2.3.99-pre5 kernel.
35 */
36
37#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
38
39#define DRV_NAME "tun"
40#define DRV_VERSION "1.6"
41#define DRV_DESCRIPTION "Universal TUN/TAP device driver"
42#define DRV_COPYRIGHT "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
43
44#include <linux/module.h>
45#include <linux/errno.h>
46#include <linux/kernel.h>
47#include <linux/major.h>
48#include <linux/slab.h>
49#include <linux/poll.h>
50#include <linux/fcntl.h>
51#include <linux/init.h>
52#include <linux/skbuff.h>
53#include <linux/netdevice.h>
54#include <linux/etherdevice.h>
55#include <linux/miscdevice.h>
56#include <linux/ethtool.h>
57#include <linux/rtnetlink.h>
58#include <linux/compat.h>
59#include <linux/if.h>
60#include <linux/if_arp.h>
61#include <linux/if_ether.h>
62#include <linux/if_tun.h>
63#include <linux/if_vlan.h>
64#include <linux/crc32.h>
65#include <linux/nsproxy.h>
66#include <linux/virtio_net.h>
67#include <linux/rcupdate.h>
68#include <net/net_namespace.h>
69#include <net/netns/generic.h>
70#include <net/rtnetlink.h>
71#include <net/sock.h>
72#include <linux/seq_file.h>
73#include <linux/uio.h>
74#include <linux/skb_array.h>
75
76#include <linux/uaccess.h>
77
78/* Uncomment to enable debugging */
79/* #define TUN_DEBUG 1 */
80
81#ifdef TUN_DEBUG
82static int debug;
83
84#define tun_debug(level, tun, fmt, args...) \
85do { \
86 if (tun->debug) \
87 netdev_printk(level, tun->dev, fmt, ##args); \
88} while (0)
89#define DBG1(level, fmt, args...) \
90do { \
91 if (debug == 2) \
92 printk(level fmt, ##args); \
93} while (0)
94#else
95#define tun_debug(level, tun, fmt, args...) \
96do { \
97 if (0) \
98 netdev_printk(level, tun->dev, fmt, ##args); \
99} while (0)
100#define DBG1(level, fmt, args...) \
101do { \
102 if (0) \
103 printk(level fmt, ##args); \
104} while (0)
105#endif
106
107/* TUN device flags */
108
109/* IFF_ATTACH_QUEUE is never stored in device flags,
110 * overload it to mean fasync when stored there.
111 */
112#define TUN_FASYNC IFF_ATTACH_QUEUE
113/* High bits in flags field are unused. */
114#define TUN_VNET_LE 0x80000000
115#define TUN_VNET_BE 0x40000000
116
117#define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
118 IFF_MULTI_QUEUE)
119#define GOODCOPY_LEN 128
120
121#define FLT_EXACT_COUNT 8
122struct tap_filter {
123 unsigned int count; /* Number of addrs. Zero means disabled */
124 u32 mask[2]; /* Mask of the hashed addrs */
125 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
126};
127
128/* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
129 * to max number of VCPUs in guest. */
130#define MAX_TAP_QUEUES 256
131#define MAX_TAP_FLOWS 4096
132
133#define TUN_FLOW_EXPIRE (3 * HZ)
134
135struct tun_pcpu_stats {
136 u64 rx_packets;
137 u64 rx_bytes;
138 u64 tx_packets;
139 u64 tx_bytes;
140 struct u64_stats_sync syncp;
141 u32 rx_dropped;
142 u32 tx_dropped;
143 u32 rx_frame_errors;
144};
145
146/* A tun_file connects an open character device to a tuntap netdevice. It
147 * also contains all socket related structures (except sock_fprog and tap_filter)
148 * to serve as one transmit queue for tuntap device. The sock_fprog and
149 * tap_filter were kept in tun_struct since they were used for filtering for the
150 * netdevice not for a specific queue (at least I didn't see the requirement for
151 * this).
152 *
153 * RCU usage:
154 * The tun_file and tun_struct are loosely coupled, the pointer from one to the
155 * other can only be read while rcu_read_lock or rtnl_lock is held.
156 */
157struct tun_file {
158 struct sock sk;
159 struct socket socket;
160 struct socket_wq wq;
161 struct tun_struct __rcu *tun;
162 struct fasync_struct *fasync;
163 /* only used for fasnyc */
164 unsigned int flags;
165 union {
166 u16 queue_index;
167 unsigned int ifindex;
168 };
169 struct list_head next;
170 struct tun_struct *detached;
171 struct skb_array tx_array;
172};
173
174struct tun_flow_entry {
175 struct hlist_node hash_link;
176 struct rcu_head rcu;
177 struct tun_struct *tun;
178
179 u32 rxhash;
180 u32 rps_rxhash;
181 int queue_index;
182 unsigned long updated;
183};
184
185#define TUN_NUM_FLOW_ENTRIES 1024
186
187/* Since the socket were moved to tun_file, to preserve the behavior of persist
188 * device, socket filter, sndbuf and vnet header size were restore when the
189 * file were attached to a persist device.
190 */
191struct tun_struct {
192 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES];
193 unsigned int numqueues;
194 unsigned int flags;
195 kuid_t owner;
196 kgid_t group;
197
198 struct net_device *dev;
199 netdev_features_t set_features;
200#define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
201 NETIF_F_TSO6|NETIF_F_UFO)
202
203 int align;
204 int vnet_hdr_sz;
205 int sndbuf;
206 struct tap_filter txflt;
207 struct sock_fprog fprog;
208 /* protected by rtnl lock */
209 bool filter_attached;
210#ifdef TUN_DEBUG
211 int debug;
212#endif
213 spinlock_t lock;
214 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
215 struct timer_list flow_gc_timer;
216 unsigned long ageing_time;
217 unsigned int numdisabled;
218 struct list_head disabled;
219 void *security;
220 u32 flow_count;
221 struct tun_pcpu_stats __percpu *pcpu_stats;
222};
223
224#ifdef CONFIG_TUN_VNET_CROSS_LE
225static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
226{
227 return tun->flags & TUN_VNET_BE ? false :
228 virtio_legacy_is_little_endian();
229}
230
231static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
232{
233 int be = !!(tun->flags & TUN_VNET_BE);
234
235 if (put_user(be, argp))
236 return -EFAULT;
237
238 return 0;
239}
240
241static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
242{
243 int be;
244
245 if (get_user(be, argp))
246 return -EFAULT;
247
248 if (be)
249 tun->flags |= TUN_VNET_BE;
250 else
251 tun->flags &= ~TUN_VNET_BE;
252
253 return 0;
254}
255#else
256static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
257{
258 return virtio_legacy_is_little_endian();
259}
260
261static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
262{
263 return -EINVAL;
264}
265
266static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
267{
268 return -EINVAL;
269}
270#endif /* CONFIG_TUN_VNET_CROSS_LE */
271
272static inline bool tun_is_little_endian(struct tun_struct *tun)
273{
274 return tun->flags & TUN_VNET_LE ||
275 tun_legacy_is_little_endian(tun);
276}
277
278static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
279{
280 return __virtio16_to_cpu(tun_is_little_endian(tun), val);
281}
282
283static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
284{
285 return __cpu_to_virtio16(tun_is_little_endian(tun), val);
286}
287
288static inline u32 tun_hashfn(u32 rxhash)
289{
290 return rxhash & 0x3ff;
291}
292
293static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
294{
295 struct tun_flow_entry *e;
296
297 hlist_for_each_entry_rcu(e, head, hash_link) {
298 if (e->rxhash == rxhash)
299 return e;
300 }
301 return NULL;
302}
303
304static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
305 struct hlist_head *head,
306 u32 rxhash, u16 queue_index)
307{
308 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
309
310 if (e) {
311 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
312 rxhash, queue_index);
313 e->updated = jiffies;
314 e->rxhash = rxhash;
315 e->rps_rxhash = 0;
316 e->queue_index = queue_index;
317 e->tun = tun;
318 hlist_add_head_rcu(&e->hash_link, head);
319 ++tun->flow_count;
320 }
321 return e;
322}
323
324static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
325{
326 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
327 e->rxhash, e->queue_index);
328 hlist_del_rcu(&e->hash_link);
329 kfree_rcu(e, rcu);
330 --tun->flow_count;
331}
332
333static void tun_flow_flush(struct tun_struct *tun)
334{
335 int i;
336
337 spin_lock_bh(&tun->lock);
338 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
339 struct tun_flow_entry *e;
340 struct hlist_node *n;
341
342 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
343 tun_flow_delete(tun, e);
344 }
345 spin_unlock_bh(&tun->lock);
346}
347
348static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
349{
350 int i;
351
352 spin_lock_bh(&tun->lock);
353 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
354 struct tun_flow_entry *e;
355 struct hlist_node *n;
356
357 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
358 if (e->queue_index == queue_index)
359 tun_flow_delete(tun, e);
360 }
361 }
362 spin_unlock_bh(&tun->lock);
363}
364
365static void tun_flow_cleanup(unsigned long data)
366{
367 struct tun_struct *tun = (struct tun_struct *)data;
368 unsigned long delay = tun->ageing_time;
369 unsigned long next_timer = jiffies + delay;
370 unsigned long count = 0;
371 int i;
372
373 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
374
375 spin_lock_bh(&tun->lock);
376 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
377 struct tun_flow_entry *e;
378 struct hlist_node *n;
379
380 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
381 unsigned long this_timer;
382 count++;
383 this_timer = e->updated + delay;
384 if (time_before_eq(this_timer, jiffies))
385 tun_flow_delete(tun, e);
386 else if (time_before(this_timer, next_timer))
387 next_timer = this_timer;
388 }
389 }
390
391 if (count)
392 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
393 spin_unlock_bh(&tun->lock);
394}
395
396static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
397 struct tun_file *tfile)
398{
399 struct hlist_head *head;
400 struct tun_flow_entry *e;
401 unsigned long delay = tun->ageing_time;
402 u16 queue_index = tfile->queue_index;
403
404 if (!rxhash)
405 return;
406 else
407 head = &tun->flows[tun_hashfn(rxhash)];
408
409 rcu_read_lock();
410
411 /* We may get a very small possibility of OOO during switching, not
412 * worth to optimize.*/
413 if (tun->numqueues == 1 || tfile->detached)
414 goto unlock;
415
416 e = tun_flow_find(head, rxhash);
417 if (likely(e)) {
418 /* TODO: keep queueing to old queue until it's empty? */
419 e->queue_index = queue_index;
420 e->updated = jiffies;
421 sock_rps_record_flow_hash(e->rps_rxhash);
422 } else {
423 spin_lock_bh(&tun->lock);
424 if (!tun_flow_find(head, rxhash) &&
425 tun->flow_count < MAX_TAP_FLOWS)
426 tun_flow_create(tun, head, rxhash, queue_index);
427
428 if (!timer_pending(&tun->flow_gc_timer))
429 mod_timer(&tun->flow_gc_timer,
430 round_jiffies_up(jiffies + delay));
431 spin_unlock_bh(&tun->lock);
432 }
433
434unlock:
435 rcu_read_unlock();
436}
437
438/**
439 * Save the hash received in the stack receive path and update the
440 * flow_hash table accordingly.
441 */
442static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
443{
444 if (unlikely(e->rps_rxhash != hash))
445 e->rps_rxhash = hash;
446}
447
448/* We try to identify a flow through its rxhash first. The reason that
449 * we do not check rxq no. is because some cards(e.g 82599), chooses
450 * the rxq based on the txq where the last packet of the flow comes. As
451 * the userspace application move between processors, we may get a
452 * different rxq no. here. If we could not get rxhash, then we would
453 * hope the rxq no. may help here.
454 */
455static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
456 void *accel_priv, select_queue_fallback_t fallback)
457{
458 struct tun_struct *tun = netdev_priv(dev);
459 struct tun_flow_entry *e;
460 u32 txq = 0;
461 u32 numqueues = 0;
462
463 rcu_read_lock();
464 numqueues = ACCESS_ONCE(tun->numqueues);
465
466 txq = skb_get_hash(skb);
467 if (txq) {
468 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
469 if (e) {
470 tun_flow_save_rps_rxhash(e, txq);
471 txq = e->queue_index;
472 } else
473 /* use multiply and shift instead of expensive divide */
474 txq = ((u64)txq * numqueues) >> 32;
475 } else if (likely(skb_rx_queue_recorded(skb))) {
476 txq = skb_get_rx_queue(skb);
477 while (unlikely(txq >= numqueues))
478 txq -= numqueues;
479 }
480
481 rcu_read_unlock();
482 return txq;
483}
484
485static inline bool tun_not_capable(struct tun_struct *tun)
486{
487 const struct cred *cred = current_cred();
488 struct net *net = dev_net(tun->dev);
489
490 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
491 (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
492 !ns_capable(net->user_ns, CAP_NET_ADMIN);
493}
494
495static void tun_set_real_num_queues(struct tun_struct *tun)
496{
497 netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
498 netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
499}
500
501static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
502{
503 tfile->detached = tun;
504 list_add_tail(&tfile->next, &tun->disabled);
505 ++tun->numdisabled;
506}
507
508static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
509{
510 struct tun_struct *tun = tfile->detached;
511
512 tfile->detached = NULL;
513 list_del_init(&tfile->next);
514 --tun->numdisabled;
515 return tun;
516}
517
518static void tun_queue_purge(struct tun_file *tfile)
519{
520 struct sk_buff *skb;
521
522 while ((skb = skb_array_consume(&tfile->tx_array)) != NULL)
523 kfree_skb(skb);
524
525 skb_queue_purge(&tfile->sk.sk_error_queue);
526}
527
528static void __tun_detach(struct tun_file *tfile, bool clean)
529{
530 struct tun_file *ntfile;
531 struct tun_struct *tun;
532
533 tun = rtnl_dereference(tfile->tun);
534
535 if (tun && !tfile->detached) {
536 u16 index = tfile->queue_index;
537 BUG_ON(index >= tun->numqueues);
538
539 rcu_assign_pointer(tun->tfiles[index],
540 tun->tfiles[tun->numqueues - 1]);
541 ntfile = rtnl_dereference(tun->tfiles[index]);
542 ntfile->queue_index = index;
543
544 --tun->numqueues;
545 if (clean) {
546 RCU_INIT_POINTER(tfile->tun, NULL);
547 sock_put(&tfile->sk);
548 } else
549 tun_disable_queue(tun, tfile);
550
551 synchronize_net();
552 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
553 /* Drop read queue */
554 tun_queue_purge(tfile);
555 tun_set_real_num_queues(tun);
556 } else if (tfile->detached && clean) {
557 tun = tun_enable_queue(tfile);
558 sock_put(&tfile->sk);
559 }
560
561 if (clean) {
562 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
563 netif_carrier_off(tun->dev);
564
565 if (!(tun->flags & IFF_PERSIST) &&
566 tun->dev->reg_state == NETREG_REGISTERED)
567 unregister_netdevice(tun->dev);
568 }
569 if (tun)
570 skb_array_cleanup(&tfile->tx_array);
571 sock_put(&tfile->sk);
572 }
573}
574
575static void tun_detach(struct tun_file *tfile, bool clean)
576{
577 rtnl_lock();
578 __tun_detach(tfile, clean);
579 rtnl_unlock();
580}
581
582static void tun_detach_all(struct net_device *dev)
583{
584 struct tun_struct *tun = netdev_priv(dev);
585 struct tun_file *tfile, *tmp;
586 int i, n = tun->numqueues;
587
588 for (i = 0; i < n; i++) {
589 tfile = rtnl_dereference(tun->tfiles[i]);
590 BUG_ON(!tfile);
591 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
592 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
593 RCU_INIT_POINTER(tfile->tun, NULL);
594 --tun->numqueues;
595 }
596 list_for_each_entry(tfile, &tun->disabled, next) {
597 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
598 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
599 RCU_INIT_POINTER(tfile->tun, NULL);
600 }
601 BUG_ON(tun->numqueues != 0);
602
603 synchronize_net();
604 for (i = 0; i < n; i++) {
605 tfile = rtnl_dereference(tun->tfiles[i]);
606 /* Drop read queue */
607 tun_queue_purge(tfile);
608 sock_put(&tfile->sk);
609 }
610 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
611 tun_enable_queue(tfile);
612 tun_queue_purge(tfile);
613 sock_put(&tfile->sk);
614 }
615 BUG_ON(tun->numdisabled != 0);
616
617 if (tun->flags & IFF_PERSIST)
618 module_put(THIS_MODULE);
619}
620
621static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter)
622{
623 struct tun_file *tfile = file->private_data;
624 struct net_device *dev = tun->dev;
625 int err;
626
627 err = security_tun_dev_attach(tfile->socket.sk, tun->security);
628 if (err < 0)
629 goto out;
630
631 err = -EINVAL;
632 if (rtnl_dereference(tfile->tun) && !tfile->detached)
633 goto out;
634
635 err = -EBUSY;
636 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
637 goto out;
638
639 err = -E2BIG;
640 if (!tfile->detached &&
641 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
642 goto out;
643
644 err = 0;
645
646 /* Re-attach the filter to persist device */
647 if (!skip_filter && (tun->filter_attached == true)) {
648 lock_sock(tfile->socket.sk);
649 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
650 release_sock(tfile->socket.sk);
651 if (!err)
652 goto out;
653 }
654
655 if (!tfile->detached &&
656 skb_array_init(&tfile->tx_array, dev->tx_queue_len, GFP_KERNEL)) {
657 err = -ENOMEM;
658 goto out;
659 }
660
661 tfile->queue_index = tun->numqueues;
662 tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
663 rcu_assign_pointer(tfile->tun, tun);
664 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
665 tun->numqueues++;
666
667 if (tfile->detached)
668 tun_enable_queue(tfile);
669 else
670 sock_hold(&tfile->sk);
671
672 tun_set_real_num_queues(tun);
673
674 /* device is allowed to go away first, so no need to hold extra
675 * refcnt.
676 */
677
678out:
679 return err;
680}
681
682static struct tun_struct *__tun_get(struct tun_file *tfile)
683{
684 struct tun_struct *tun;
685
686 rcu_read_lock();
687 tun = rcu_dereference(tfile->tun);
688 if (tun)
689 dev_hold(tun->dev);
690 rcu_read_unlock();
691
692 return tun;
693}
694
695static struct tun_struct *tun_get(struct file *file)
696{
697 return __tun_get(file->private_data);
698}
699
700static void tun_put(struct tun_struct *tun)
701{
702 dev_put(tun->dev);
703}
704
705/* TAP filtering */
706static void addr_hash_set(u32 *mask, const u8 *addr)
707{
708 int n = ether_crc(ETH_ALEN, addr) >> 26;
709 mask[n >> 5] |= (1 << (n & 31));
710}
711
712static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
713{
714 int n = ether_crc(ETH_ALEN, addr) >> 26;
715 return mask[n >> 5] & (1 << (n & 31));
716}
717
718static int update_filter(struct tap_filter *filter, void __user *arg)
719{
720 struct { u8 u[ETH_ALEN]; } *addr;
721 struct tun_filter uf;
722 int err, alen, n, nexact;
723
724 if (copy_from_user(&uf, arg, sizeof(uf)))
725 return -EFAULT;
726
727 if (!uf.count) {
728 /* Disabled */
729 filter->count = 0;
730 return 0;
731 }
732
733 alen = ETH_ALEN * uf.count;
734 addr = memdup_user(arg + sizeof(uf), alen);
735 if (IS_ERR(addr))
736 return PTR_ERR(addr);
737
738 /* The filter is updated without holding any locks. Which is
739 * perfectly safe. We disable it first and in the worst
740 * case we'll accept a few undesired packets. */
741 filter->count = 0;
742 wmb();
743
744 /* Use first set of addresses as an exact filter */
745 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
746 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
747
748 nexact = n;
749
750 /* Remaining multicast addresses are hashed,
751 * unicast will leave the filter disabled. */
752 memset(filter->mask, 0, sizeof(filter->mask));
753 for (; n < uf.count; n++) {
754 if (!is_multicast_ether_addr(addr[n].u)) {
755 err = 0; /* no filter */
756 goto free_addr;
757 }
758 addr_hash_set(filter->mask, addr[n].u);
759 }
760
761 /* For ALLMULTI just set the mask to all ones.
762 * This overrides the mask populated above. */
763 if ((uf.flags & TUN_FLT_ALLMULTI))
764 memset(filter->mask, ~0, sizeof(filter->mask));
765
766 /* Now enable the filter */
767 wmb();
768 filter->count = nexact;
769
770 /* Return the number of exact filters */
771 err = nexact;
772free_addr:
773 kfree(addr);
774 return err;
775}
776
777/* Returns: 0 - drop, !=0 - accept */
778static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
779{
780 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
781 * at this point. */
782 struct ethhdr *eh = (struct ethhdr *) skb->data;
783 int i;
784
785 /* Exact match */
786 for (i = 0; i < filter->count; i++)
787 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
788 return 1;
789
790 /* Inexact match (multicast only) */
791 if (is_multicast_ether_addr(eh->h_dest))
792 return addr_hash_test(filter->mask, eh->h_dest);
793
794 return 0;
795}
796
797/*
798 * Checks whether the packet is accepted or not.
799 * Returns: 0 - drop, !=0 - accept
800 */
801static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
802{
803 if (!filter->count)
804 return 1;
805
806 return run_filter(filter, skb);
807}
808
809/* Network device part of the driver */
810
811static const struct ethtool_ops tun_ethtool_ops;
812
813/* Net device detach from fd. */
814static void tun_net_uninit(struct net_device *dev)
815{
816 tun_detach_all(dev);
817}
818
819/* Net device open. */
820static int tun_net_open(struct net_device *dev)
821{
822 struct tun_struct *tun = netdev_priv(dev);
823 int i;
824
825 netif_tx_start_all_queues(dev);
826
827 for (i = 0; i < tun->numqueues; i++) {
828 struct tun_file *tfile;
829
830 tfile = rtnl_dereference(tun->tfiles[i]);
831 tfile->socket.sk->sk_write_space(tfile->socket.sk);
832 }
833
834 return 0;
835}
836
837/* Net device close. */
838static int tun_net_close(struct net_device *dev)
839{
840 netif_tx_stop_all_queues(dev);
841 return 0;
842}
843
844/* Net device start xmit */
845static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
846{
847 struct tun_struct *tun = netdev_priv(dev);
848 int txq = skb->queue_mapping;
849 struct tun_file *tfile;
850 u32 numqueues = 0;
851
852 rcu_read_lock();
853 tfile = rcu_dereference(tun->tfiles[txq]);
854 numqueues = ACCESS_ONCE(tun->numqueues);
855
856 /* Drop packet if interface is not attached */
857 if (txq >= numqueues)
858 goto drop;
859
860#ifdef CONFIG_RPS
861 if (numqueues == 1 && static_key_false(&rps_needed)) {
862 /* Select queue was not called for the skbuff, so we extract the
863 * RPS hash and save it into the flow_table here.
864 */
865 __u32 rxhash;
866
867 rxhash = skb_get_hash(skb);
868 if (rxhash) {
869 struct tun_flow_entry *e;
870 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)],
871 rxhash);
872 if (e)
873 tun_flow_save_rps_rxhash(e, rxhash);
874 }
875 }
876#endif
877
878 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
879
880 BUG_ON(!tfile);
881
882 /* Drop if the filter does not like it.
883 * This is a noop if the filter is disabled.
884 * Filter can be enabled only for the TAP devices. */
885 if (!check_filter(&tun->txflt, skb))
886 goto drop;
887
888 if (tfile->socket.sk->sk_filter &&
889 sk_filter(tfile->socket.sk, skb))
890 goto drop;
891
892 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
893 goto drop;
894
895 skb_tx_timestamp(skb);
896
897 /* Orphan the skb - required as we might hang on to it
898 * for indefinite time.
899 */
900 skb_orphan(skb);
901
902 nf_reset(skb);
903
904 if (skb_array_produce(&tfile->tx_array, skb))
905 goto drop;
906
907 /* Notify and wake up reader process */
908 if (tfile->flags & TUN_FASYNC)
909 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
910 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
911
912 rcu_read_unlock();
913 return NETDEV_TX_OK;
914
915drop:
916 this_cpu_inc(tun->pcpu_stats->tx_dropped);
917 skb_tx_error(skb);
918 kfree_skb(skb);
919 rcu_read_unlock();
920 return NET_XMIT_DROP;
921}
922
923static void tun_net_mclist(struct net_device *dev)
924{
925 /*
926 * This callback is supposed to deal with mc filter in
927 * _rx_ path and has nothing to do with the _tx_ path.
928 * In rx path we always accept everything userspace gives us.
929 */
930}
931
932static netdev_features_t tun_net_fix_features(struct net_device *dev,
933 netdev_features_t features)
934{
935 struct tun_struct *tun = netdev_priv(dev);
936
937 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
938}
939#ifdef CONFIG_NET_POLL_CONTROLLER
940static void tun_poll_controller(struct net_device *dev)
941{
942 /*
943 * Tun only receives frames when:
944 * 1) the char device endpoint gets data from user space
945 * 2) the tun socket gets a sendmsg call from user space
946 * Since both of those are synchronous operations, we are guaranteed
947 * never to have pending data when we poll for it
948 * so there is nothing to do here but return.
949 * We need this though so netpoll recognizes us as an interface that
950 * supports polling, which enables bridge devices in virt setups to
951 * still use netconsole
952 */
953 return;
954}
955#endif
956
957static void tun_set_headroom(struct net_device *dev, int new_hr)
958{
959 struct tun_struct *tun = netdev_priv(dev);
960
961 if (new_hr < NET_SKB_PAD)
962 new_hr = NET_SKB_PAD;
963
964 tun->align = new_hr;
965}
966
967static struct rtnl_link_stats64 *
968tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
969{
970 u32 rx_dropped = 0, tx_dropped = 0, rx_frame_errors = 0;
971 struct tun_struct *tun = netdev_priv(dev);
972 struct tun_pcpu_stats *p;
973 int i;
974
975 for_each_possible_cpu(i) {
976 u64 rxpackets, rxbytes, txpackets, txbytes;
977 unsigned int start;
978
979 p = per_cpu_ptr(tun->pcpu_stats, i);
980 do {
981 start = u64_stats_fetch_begin(&p->syncp);
982 rxpackets = p->rx_packets;
983 rxbytes = p->rx_bytes;
984 txpackets = p->tx_packets;
985 txbytes = p->tx_bytes;
986 } while (u64_stats_fetch_retry(&p->syncp, start));
987
988 stats->rx_packets += rxpackets;
989 stats->rx_bytes += rxbytes;
990 stats->tx_packets += txpackets;
991 stats->tx_bytes += txbytes;
992
993 /* u32 counters */
994 rx_dropped += p->rx_dropped;
995 rx_frame_errors += p->rx_frame_errors;
996 tx_dropped += p->tx_dropped;
997 }
998 stats->rx_dropped = rx_dropped;
999 stats->rx_frame_errors = rx_frame_errors;
1000 stats->tx_dropped = tx_dropped;
1001 return stats;
1002}
1003
1004static const struct net_device_ops tun_netdev_ops = {
1005 .ndo_uninit = tun_net_uninit,
1006 .ndo_open = tun_net_open,
1007 .ndo_stop = tun_net_close,
1008 .ndo_start_xmit = tun_net_xmit,
1009 .ndo_fix_features = tun_net_fix_features,
1010 .ndo_select_queue = tun_select_queue,
1011#ifdef CONFIG_NET_POLL_CONTROLLER
1012 .ndo_poll_controller = tun_poll_controller,
1013#endif
1014 .ndo_set_rx_headroom = tun_set_headroom,
1015 .ndo_get_stats64 = tun_net_get_stats64,
1016};
1017
1018static const struct net_device_ops tap_netdev_ops = {
1019 .ndo_uninit = tun_net_uninit,
1020 .ndo_open = tun_net_open,
1021 .ndo_stop = tun_net_close,
1022 .ndo_start_xmit = tun_net_xmit,
1023 .ndo_fix_features = tun_net_fix_features,
1024 .ndo_set_rx_mode = tun_net_mclist,
1025 .ndo_set_mac_address = eth_mac_addr,
1026 .ndo_validate_addr = eth_validate_addr,
1027 .ndo_select_queue = tun_select_queue,
1028#ifdef CONFIG_NET_POLL_CONTROLLER
1029 .ndo_poll_controller = tun_poll_controller,
1030#endif
1031 .ndo_features_check = passthru_features_check,
1032 .ndo_set_rx_headroom = tun_set_headroom,
1033 .ndo_get_stats64 = tun_net_get_stats64,
1034};
1035
1036static void tun_flow_init(struct tun_struct *tun)
1037{
1038 int i;
1039
1040 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1041 INIT_HLIST_HEAD(&tun->flows[i]);
1042
1043 tun->ageing_time = TUN_FLOW_EXPIRE;
1044 setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun);
1045 mod_timer(&tun->flow_gc_timer,
1046 round_jiffies_up(jiffies + tun->ageing_time));
1047}
1048
1049static void tun_flow_uninit(struct tun_struct *tun)
1050{
1051 del_timer_sync(&tun->flow_gc_timer);
1052 tun_flow_flush(tun);
1053}
1054
1055#define MIN_MTU 68
1056#define MAX_MTU 65535
1057
1058/* Initialize net device. */
1059static void tun_net_init(struct net_device *dev)
1060{
1061 struct tun_struct *tun = netdev_priv(dev);
1062
1063 switch (tun->flags & TUN_TYPE_MASK) {
1064 case IFF_TUN:
1065 dev->netdev_ops = &tun_netdev_ops;
1066
1067 /* Point-to-Point TUN Device */
1068 dev->hard_header_len = 0;
1069 dev->addr_len = 0;
1070 dev->mtu = 1500;
1071
1072 /* Zero header length */
1073 dev->type = ARPHRD_NONE;
1074 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1075 break;
1076
1077 case IFF_TAP:
1078 dev->netdev_ops = &tap_netdev_ops;
1079 /* Ethernet TAP Device */
1080 ether_setup(dev);
1081 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1082 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1083
1084 eth_hw_addr_random(dev);
1085
1086 break;
1087 }
1088
1089 dev->min_mtu = MIN_MTU;
1090 dev->max_mtu = MAX_MTU - dev->hard_header_len;
1091}
1092
1093/* Character device part */
1094
1095/* Poll */
1096static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
1097{
1098 struct tun_file *tfile = file->private_data;
1099 struct tun_struct *tun = __tun_get(tfile);
1100 struct sock *sk;
1101 unsigned int mask = 0;
1102
1103 if (!tun)
1104 return POLLERR;
1105
1106 sk = tfile->socket.sk;
1107
1108 tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
1109
1110 poll_wait(file, sk_sleep(sk), wait);
1111
1112 if (!skb_array_empty(&tfile->tx_array))
1113 mask |= POLLIN | POLLRDNORM;
1114
1115 if (tun->dev->flags & IFF_UP &&
1116 (sock_writeable(sk) ||
1117 (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1118 sock_writeable(sk))))
1119 mask |= POLLOUT | POLLWRNORM;
1120
1121 if (tun->dev->reg_state != NETREG_REGISTERED)
1122 mask = POLLERR;
1123
1124 tun_put(tun);
1125 return mask;
1126}
1127
1128/* prepad is the amount to reserve at front. len is length after that.
1129 * linear is a hint as to how much to copy (usually headers). */
1130static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1131 size_t prepad, size_t len,
1132 size_t linear, int noblock)
1133{
1134 struct sock *sk = tfile->socket.sk;
1135 struct sk_buff *skb;
1136 int err;
1137
1138 /* Under a page? Don't bother with paged skb. */
1139 if (prepad + len < PAGE_SIZE || !linear)
1140 linear = len;
1141
1142 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1143 &err, 0);
1144 if (!skb)
1145 return ERR_PTR(err);
1146
1147 skb_reserve(skb, prepad);
1148 skb_put(skb, linear);
1149 skb->data_len = len - linear;
1150 skb->len += len - linear;
1151
1152 return skb;
1153}
1154
1155/* Get packet from user space buffer */
1156static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1157 void *msg_control, struct iov_iter *from,
1158 int noblock)
1159{
1160 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1161 struct sk_buff *skb;
1162 size_t total_len = iov_iter_count(from);
1163 size_t len = total_len, align = tun->align, linear;
1164 struct virtio_net_hdr gso = { 0 };
1165 struct tun_pcpu_stats *stats;
1166 int good_linear;
1167 int copylen;
1168 bool zerocopy = false;
1169 int err;
1170 u32 rxhash;
1171
1172 if (!(tun->dev->flags & IFF_UP))
1173 return -EIO;
1174
1175 if (!(tun->flags & IFF_NO_PI)) {
1176 if (len < sizeof(pi))
1177 return -EINVAL;
1178 len -= sizeof(pi);
1179
1180 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1181 return -EFAULT;
1182 }
1183
1184 if (tun->flags & IFF_VNET_HDR) {
1185 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1186
1187 if (len < vnet_hdr_sz)
1188 return -EINVAL;
1189 len -= vnet_hdr_sz;
1190
1191 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1192 return -EFAULT;
1193
1194 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1195 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1196 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1197
1198 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1199 return -EINVAL;
1200 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1201 }
1202
1203 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1204 align += NET_IP_ALIGN;
1205 if (unlikely(len < ETH_HLEN ||
1206 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1207 return -EINVAL;
1208 }
1209
1210 good_linear = SKB_MAX_HEAD(align);
1211
1212 if (msg_control) {
1213 struct iov_iter i = *from;
1214
1215 /* There are 256 bytes to be copied in skb, so there is
1216 * enough room for skb expand head in case it is used.
1217 * The rest of the buffer is mapped from userspace.
1218 */
1219 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1220 if (copylen > good_linear)
1221 copylen = good_linear;
1222 linear = copylen;
1223 iov_iter_advance(&i, copylen);
1224 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1225 zerocopy = true;
1226 }
1227
1228 if (!zerocopy) {
1229 copylen = len;
1230 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1231 linear = good_linear;
1232 else
1233 linear = tun16_to_cpu(tun, gso.hdr_len);
1234 }
1235
1236 skb = tun_alloc_skb(tfile, align, copylen, linear, noblock);
1237 if (IS_ERR(skb)) {
1238 if (PTR_ERR(skb) != -EAGAIN)
1239 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1240 return PTR_ERR(skb);
1241 }
1242
1243 if (zerocopy)
1244 err = zerocopy_sg_from_iter(skb, from);
1245 else
1246 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1247
1248 if (err) {
1249 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1250 kfree_skb(skb);
1251 return -EFAULT;
1252 }
1253
1254 if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1255 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
1256 kfree_skb(skb);
1257 return -EINVAL;
1258 }
1259
1260 switch (tun->flags & TUN_TYPE_MASK) {
1261 case IFF_TUN:
1262 if (tun->flags & IFF_NO_PI) {
1263 switch (skb->data[0] & 0xf0) {
1264 case 0x40:
1265 pi.proto = htons(ETH_P_IP);
1266 break;
1267 case 0x60:
1268 pi.proto = htons(ETH_P_IPV6);
1269 break;
1270 default:
1271 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1272 kfree_skb(skb);
1273 return -EINVAL;
1274 }
1275 }
1276
1277 skb_reset_mac_header(skb);
1278 skb->protocol = pi.proto;
1279 skb->dev = tun->dev;
1280 break;
1281 case IFF_TAP:
1282 skb->protocol = eth_type_trans(skb, tun->dev);
1283 break;
1284 }
1285
1286 /* copy skb_ubuf_info for callback when skb has no error */
1287 if (zerocopy) {
1288 skb_shinfo(skb)->destructor_arg = msg_control;
1289 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1290 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1291 } else if (msg_control) {
1292 struct ubuf_info *uarg = msg_control;
1293 uarg->callback(uarg, false);
1294 }
1295
1296 skb_reset_network_header(skb);
1297 skb_probe_transport_header(skb, 0);
1298
1299 rxhash = skb_get_hash(skb);
1300#ifndef CONFIG_4KSTACKS
1301 local_bh_disable();
1302 netif_receive_skb(skb);
1303 local_bh_enable();
1304#else
1305 netif_rx_ni(skb);
1306#endif
1307
1308 stats = get_cpu_ptr(tun->pcpu_stats);
1309 u64_stats_update_begin(&stats->syncp);
1310 stats->rx_packets++;
1311 stats->rx_bytes += len;
1312 u64_stats_update_end(&stats->syncp);
1313 put_cpu_ptr(stats);
1314
1315 tun_flow_update(tun, rxhash, tfile);
1316 return total_len;
1317}
1318
1319static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
1320{
1321 struct file *file = iocb->ki_filp;
1322 struct tun_struct *tun = tun_get(file);
1323 struct tun_file *tfile = file->private_data;
1324 ssize_t result;
1325
1326 if (!tun)
1327 return -EBADFD;
1328
1329 result = tun_get_user(tun, tfile, NULL, from, file->f_flags & O_NONBLOCK);
1330
1331 tun_put(tun);
1332 return result;
1333}
1334
1335/* Put packet to the user space buffer */
1336static ssize_t tun_put_user(struct tun_struct *tun,
1337 struct tun_file *tfile,
1338 struct sk_buff *skb,
1339 struct iov_iter *iter)
1340{
1341 struct tun_pi pi = { 0, skb->protocol };
1342 struct tun_pcpu_stats *stats;
1343 ssize_t total;
1344 int vlan_offset = 0;
1345 int vlan_hlen = 0;
1346 int vnet_hdr_sz = 0;
1347
1348 if (skb_vlan_tag_present(skb))
1349 vlan_hlen = VLAN_HLEN;
1350
1351 if (tun->flags & IFF_VNET_HDR)
1352 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1353
1354 total = skb->len + vlan_hlen + vnet_hdr_sz;
1355
1356 if (!(tun->flags & IFF_NO_PI)) {
1357 if (iov_iter_count(iter) < sizeof(pi))
1358 return -EINVAL;
1359
1360 total += sizeof(pi);
1361 if (iov_iter_count(iter) < total) {
1362 /* Packet will be striped */
1363 pi.flags |= TUN_PKT_STRIP;
1364 }
1365
1366 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
1367 return -EFAULT;
1368 }
1369
1370 if (vnet_hdr_sz) {
1371 struct virtio_net_hdr gso;
1372
1373 if (iov_iter_count(iter) < vnet_hdr_sz)
1374 return -EINVAL;
1375
1376 if (virtio_net_hdr_from_skb(skb, &gso,
1377 tun_is_little_endian(tun), true)) {
1378 struct skb_shared_info *sinfo = skb_shinfo(skb);
1379 pr_err("unexpected GSO type: "
1380 "0x%x, gso_size %d, hdr_len %d\n",
1381 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
1382 tun16_to_cpu(tun, gso.hdr_len));
1383 print_hex_dump(KERN_ERR, "tun: ",
1384 DUMP_PREFIX_NONE,
1385 16, 1, skb->head,
1386 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
1387 WARN_ON_ONCE(1);
1388 return -EINVAL;
1389 }
1390
1391 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
1392 return -EFAULT;
1393
1394 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
1395 }
1396
1397 if (vlan_hlen) {
1398 int ret;
1399 struct {
1400 __be16 h_vlan_proto;
1401 __be16 h_vlan_TCI;
1402 } veth;
1403
1404 veth.h_vlan_proto = skb->vlan_proto;
1405 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
1406
1407 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
1408
1409 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
1410 if (ret || !iov_iter_count(iter))
1411 goto done;
1412
1413 ret = copy_to_iter(&veth, sizeof(veth), iter);
1414 if (ret != sizeof(veth) || !iov_iter_count(iter))
1415 goto done;
1416 }
1417
1418 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
1419
1420done:
1421 /* caller is in process context, */
1422 stats = get_cpu_ptr(tun->pcpu_stats);
1423 u64_stats_update_begin(&stats->syncp);
1424 stats->tx_packets++;
1425 stats->tx_bytes += skb->len + vlan_hlen;
1426 u64_stats_update_end(&stats->syncp);
1427 put_cpu_ptr(tun->pcpu_stats);
1428
1429 return total;
1430}
1431
1432static struct sk_buff *tun_ring_recv(struct tun_file *tfile, int noblock,
1433 int *err)
1434{
1435 DECLARE_WAITQUEUE(wait, current);
1436 struct sk_buff *skb = NULL;
1437 int error = 0;
1438
1439 skb = skb_array_consume(&tfile->tx_array);
1440 if (skb)
1441 goto out;
1442 if (noblock) {
1443 error = -EAGAIN;
1444 goto out;
1445 }
1446
1447 add_wait_queue(&tfile->wq.wait, &wait);
1448 current->state = TASK_INTERRUPTIBLE;
1449
1450 while (1) {
1451 skb = skb_array_consume(&tfile->tx_array);
1452 if (skb)
1453 break;
1454 if (signal_pending(current)) {
1455 error = -ERESTARTSYS;
1456 break;
1457 }
1458 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
1459 error = -EFAULT;
1460 break;
1461 }
1462
1463 schedule();
1464 }
1465
1466 current->state = TASK_RUNNING;
1467 remove_wait_queue(&tfile->wq.wait, &wait);
1468
1469out:
1470 *err = error;
1471 return skb;
1472}
1473
1474static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
1475 struct iov_iter *to,
1476 int noblock)
1477{
1478 struct sk_buff *skb;
1479 ssize_t ret;
1480 int err;
1481
1482 tun_debug(KERN_INFO, tun, "tun_do_read\n");
1483
1484 if (!iov_iter_count(to))
1485 return 0;
1486
1487 /* Read frames from ring */
1488 skb = tun_ring_recv(tfile, noblock, &err);
1489 if (!skb)
1490 return err;
1491
1492 ret = tun_put_user(tun, tfile, skb, to);
1493 if (unlikely(ret < 0))
1494 kfree_skb(skb);
1495 else
1496 consume_skb(skb);
1497
1498 return ret;
1499}
1500
1501static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
1502{
1503 struct file *file = iocb->ki_filp;
1504 struct tun_file *tfile = file->private_data;
1505 struct tun_struct *tun = __tun_get(tfile);
1506 ssize_t len = iov_iter_count(to), ret;
1507
1508 if (!tun)
1509 return -EBADFD;
1510 ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK);
1511 ret = min_t(ssize_t, ret, len);
1512 if (ret > 0)
1513 iocb->ki_pos = ret;
1514 tun_put(tun);
1515 return ret;
1516}
1517
1518static void tun_free_netdev(struct net_device *dev)
1519{
1520 struct tun_struct *tun = netdev_priv(dev);
1521
1522 BUG_ON(!(list_empty(&tun->disabled)));
1523 free_percpu(tun->pcpu_stats);
1524 tun_flow_uninit(tun);
1525 security_tun_dev_free_security(tun->security);
1526 free_netdev(dev);
1527}
1528
1529static void tun_setup(struct net_device *dev)
1530{
1531 struct tun_struct *tun = netdev_priv(dev);
1532
1533 tun->owner = INVALID_UID;
1534 tun->group = INVALID_GID;
1535
1536 dev->ethtool_ops = &tun_ethtool_ops;
1537 dev->destructor = tun_free_netdev;
1538 /* We prefer our own queue length */
1539 dev->tx_queue_len = TUN_READQ_SIZE;
1540}
1541
1542/* Trivial set of netlink ops to allow deleting tun or tap
1543 * device with netlink.
1544 */
1545static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
1546{
1547 return -EINVAL;
1548}
1549
1550static struct rtnl_link_ops tun_link_ops __read_mostly = {
1551 .kind = DRV_NAME,
1552 .priv_size = sizeof(struct tun_struct),
1553 .setup = tun_setup,
1554 .validate = tun_validate,
1555};
1556
1557static void tun_sock_write_space(struct sock *sk)
1558{
1559 struct tun_file *tfile;
1560 wait_queue_head_t *wqueue;
1561
1562 if (!sock_writeable(sk))
1563 return;
1564
1565 if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
1566 return;
1567
1568 wqueue = sk_sleep(sk);
1569 if (wqueue && waitqueue_active(wqueue))
1570 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1571 POLLWRNORM | POLLWRBAND);
1572
1573 tfile = container_of(sk, struct tun_file, sk);
1574 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
1575}
1576
1577static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
1578{
1579 int ret;
1580 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1581 struct tun_struct *tun = __tun_get(tfile);
1582
1583 if (!tun)
1584 return -EBADFD;
1585
1586 ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter,
1587 m->msg_flags & MSG_DONTWAIT);
1588 tun_put(tun);
1589 return ret;
1590}
1591
1592static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
1593 int flags)
1594{
1595 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1596 struct tun_struct *tun = __tun_get(tfile);
1597 int ret;
1598
1599 if (!tun)
1600 return -EBADFD;
1601
1602 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
1603 ret = -EINVAL;
1604 goto out;
1605 }
1606 if (flags & MSG_ERRQUEUE) {
1607 ret = sock_recv_errqueue(sock->sk, m, total_len,
1608 SOL_PACKET, TUN_TX_TIMESTAMP);
1609 goto out;
1610 }
1611 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT);
1612 if (ret > (ssize_t)total_len) {
1613 m->msg_flags |= MSG_TRUNC;
1614 ret = flags & MSG_TRUNC ? ret : total_len;
1615 }
1616out:
1617 tun_put(tun);
1618 return ret;
1619}
1620
1621static int tun_peek_len(struct socket *sock)
1622{
1623 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1624 struct tun_struct *tun;
1625 int ret = 0;
1626
1627 tun = __tun_get(tfile);
1628 if (!tun)
1629 return 0;
1630
1631 ret = skb_array_peek_len(&tfile->tx_array);
1632 tun_put(tun);
1633
1634 return ret;
1635}
1636
1637/* Ops structure to mimic raw sockets with tun */
1638static const struct proto_ops tun_socket_ops = {
1639 .peek_len = tun_peek_len,
1640 .sendmsg = tun_sendmsg,
1641 .recvmsg = tun_recvmsg,
1642};
1643
1644static struct proto tun_proto = {
1645 .name = "tun",
1646 .owner = THIS_MODULE,
1647 .obj_size = sizeof(struct tun_file),
1648};
1649
1650static int tun_flags(struct tun_struct *tun)
1651{
1652 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
1653}
1654
1655static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1656 char *buf)
1657{
1658 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1659 return sprintf(buf, "0x%x\n", tun_flags(tun));
1660}
1661
1662static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1663 char *buf)
1664{
1665 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1666 return uid_valid(tun->owner)?
1667 sprintf(buf, "%u\n",
1668 from_kuid_munged(current_user_ns(), tun->owner)):
1669 sprintf(buf, "-1\n");
1670}
1671
1672static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1673 char *buf)
1674{
1675 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1676 return gid_valid(tun->group) ?
1677 sprintf(buf, "%u\n",
1678 from_kgid_munged(current_user_ns(), tun->group)):
1679 sprintf(buf, "-1\n");
1680}
1681
1682static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1683static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1684static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1685
1686static struct attribute *tun_dev_attrs[] = {
1687 &dev_attr_tun_flags.attr,
1688 &dev_attr_owner.attr,
1689 &dev_attr_group.attr,
1690 NULL
1691};
1692
1693static const struct attribute_group tun_attr_group = {
1694 .attrs = tun_dev_attrs
1695};
1696
1697static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1698{
1699 struct tun_struct *tun;
1700 struct tun_file *tfile = file->private_data;
1701 struct net_device *dev;
1702 int err;
1703
1704 if (tfile->detached)
1705 return -EINVAL;
1706
1707 dev = __dev_get_by_name(net, ifr->ifr_name);
1708 if (dev) {
1709 if (ifr->ifr_flags & IFF_TUN_EXCL)
1710 return -EBUSY;
1711 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1712 tun = netdev_priv(dev);
1713 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1714 tun = netdev_priv(dev);
1715 else
1716 return -EINVAL;
1717
1718 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
1719 !!(tun->flags & IFF_MULTI_QUEUE))
1720 return -EINVAL;
1721
1722 if (tun_not_capable(tun))
1723 return -EPERM;
1724 err = security_tun_dev_open(tun->security);
1725 if (err < 0)
1726 return err;
1727
1728 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER);
1729 if (err < 0)
1730 return err;
1731
1732 if (tun->flags & IFF_MULTI_QUEUE &&
1733 (tun->numqueues + tun->numdisabled > 1)) {
1734 /* One or more queue has already been attached, no need
1735 * to initialize the device again.
1736 */
1737 return 0;
1738 }
1739 }
1740 else {
1741 char *name;
1742 unsigned long flags = 0;
1743 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
1744 MAX_TAP_QUEUES : 1;
1745
1746 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1747 return -EPERM;
1748 err = security_tun_dev_create();
1749 if (err < 0)
1750 return err;
1751
1752 /* Set dev type */
1753 if (ifr->ifr_flags & IFF_TUN) {
1754 /* TUN device */
1755 flags |= IFF_TUN;
1756 name = "tun%d";
1757 } else if (ifr->ifr_flags & IFF_TAP) {
1758 /* TAP device */
1759 flags |= IFF_TAP;
1760 name = "tap%d";
1761 } else
1762 return -EINVAL;
1763
1764 if (*ifr->ifr_name)
1765 name = ifr->ifr_name;
1766
1767 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
1768 NET_NAME_UNKNOWN, tun_setup, queues,
1769 queues);
1770
1771 if (!dev)
1772 return -ENOMEM;
1773
1774 dev_net_set(dev, net);
1775 dev->rtnl_link_ops = &tun_link_ops;
1776 dev->ifindex = tfile->ifindex;
1777 dev->sysfs_groups[0] = &tun_attr_group;
1778
1779 tun = netdev_priv(dev);
1780 tun->dev = dev;
1781 tun->flags = flags;
1782 tun->txflt.count = 0;
1783 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1784
1785 tun->align = NET_SKB_PAD;
1786 tun->filter_attached = false;
1787 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
1788
1789 tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats);
1790 if (!tun->pcpu_stats) {
1791 err = -ENOMEM;
1792 goto err_free_dev;
1793 }
1794
1795 spin_lock_init(&tun->lock);
1796
1797 err = security_tun_dev_alloc_security(&tun->security);
1798 if (err < 0)
1799 goto err_free_stat;
1800
1801 tun_net_init(dev);
1802 tun_flow_init(tun);
1803
1804 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1805 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
1806 NETIF_F_HW_VLAN_STAG_TX;
1807 dev->features = dev->hw_features | NETIF_F_LLTX;
1808 dev->vlan_features = dev->features &
1809 ~(NETIF_F_HW_VLAN_CTAG_TX |
1810 NETIF_F_HW_VLAN_STAG_TX);
1811
1812 INIT_LIST_HEAD(&tun->disabled);
1813 err = tun_attach(tun, file, false);
1814 if (err < 0)
1815 goto err_free_flow;
1816
1817 err = register_netdevice(tun->dev);
1818 if (err < 0)
1819 goto err_detach;
1820 }
1821
1822 netif_carrier_on(tun->dev);
1823
1824 tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1825
1826 tun->flags = (tun->flags & ~TUN_FEATURES) |
1827 (ifr->ifr_flags & TUN_FEATURES);
1828
1829 /* Make sure persistent devices do not get stuck in
1830 * xoff state.
1831 */
1832 if (netif_running(tun->dev))
1833 netif_tx_wake_all_queues(tun->dev);
1834
1835 strcpy(ifr->ifr_name, tun->dev->name);
1836 return 0;
1837
1838err_detach:
1839 tun_detach_all(dev);
1840err_free_flow:
1841 tun_flow_uninit(tun);
1842 security_tun_dev_free_security(tun->security);
1843err_free_stat:
1844 free_percpu(tun->pcpu_stats);
1845err_free_dev:
1846 free_netdev(dev);
1847 return err;
1848}
1849
1850static void tun_get_iff(struct net *net, struct tun_struct *tun,
1851 struct ifreq *ifr)
1852{
1853 tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1854
1855 strcpy(ifr->ifr_name, tun->dev->name);
1856
1857 ifr->ifr_flags = tun_flags(tun);
1858
1859}
1860
1861/* This is like a cut-down ethtool ops, except done via tun fd so no
1862 * privs required. */
1863static int set_offload(struct tun_struct *tun, unsigned long arg)
1864{
1865 netdev_features_t features = 0;
1866
1867 if (arg & TUN_F_CSUM) {
1868 features |= NETIF_F_HW_CSUM;
1869 arg &= ~TUN_F_CSUM;
1870
1871 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1872 if (arg & TUN_F_TSO_ECN) {
1873 features |= NETIF_F_TSO_ECN;
1874 arg &= ~TUN_F_TSO_ECN;
1875 }
1876 if (arg & TUN_F_TSO4)
1877 features |= NETIF_F_TSO;
1878 if (arg & TUN_F_TSO6)
1879 features |= NETIF_F_TSO6;
1880 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1881 }
1882
1883 if (arg & TUN_F_UFO) {
1884 features |= NETIF_F_UFO;
1885 arg &= ~TUN_F_UFO;
1886 }
1887 }
1888
1889 /* This gives the user a way to test for new features in future by
1890 * trying to set them. */
1891 if (arg)
1892 return -EINVAL;
1893
1894 tun->set_features = features;
1895 netdev_update_features(tun->dev);
1896
1897 return 0;
1898}
1899
1900static void tun_detach_filter(struct tun_struct *tun, int n)
1901{
1902 int i;
1903 struct tun_file *tfile;
1904
1905 for (i = 0; i < n; i++) {
1906 tfile = rtnl_dereference(tun->tfiles[i]);
1907 lock_sock(tfile->socket.sk);
1908 sk_detach_filter(tfile->socket.sk);
1909 release_sock(tfile->socket.sk);
1910 }
1911
1912 tun->filter_attached = false;
1913}
1914
1915static int tun_attach_filter(struct tun_struct *tun)
1916{
1917 int i, ret = 0;
1918 struct tun_file *tfile;
1919
1920 for (i = 0; i < tun->numqueues; i++) {
1921 tfile = rtnl_dereference(tun->tfiles[i]);
1922 lock_sock(tfile->socket.sk);
1923 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
1924 release_sock(tfile->socket.sk);
1925 if (ret) {
1926 tun_detach_filter(tun, i);
1927 return ret;
1928 }
1929 }
1930
1931 tun->filter_attached = true;
1932 return ret;
1933}
1934
1935static void tun_set_sndbuf(struct tun_struct *tun)
1936{
1937 struct tun_file *tfile;
1938 int i;
1939
1940 for (i = 0; i < tun->numqueues; i++) {
1941 tfile = rtnl_dereference(tun->tfiles[i]);
1942 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
1943 }
1944}
1945
1946static int tun_set_queue(struct file *file, struct ifreq *ifr)
1947{
1948 struct tun_file *tfile = file->private_data;
1949 struct tun_struct *tun;
1950 int ret = 0;
1951
1952 rtnl_lock();
1953
1954 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
1955 tun = tfile->detached;
1956 if (!tun) {
1957 ret = -EINVAL;
1958 goto unlock;
1959 }
1960 ret = security_tun_dev_attach_queue(tun->security);
1961 if (ret < 0)
1962 goto unlock;
1963 ret = tun_attach(tun, file, false);
1964 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
1965 tun = rtnl_dereference(tfile->tun);
1966 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
1967 ret = -EINVAL;
1968 else
1969 __tun_detach(tfile, false);
1970 } else
1971 ret = -EINVAL;
1972
1973unlock:
1974 rtnl_unlock();
1975 return ret;
1976}
1977
1978static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1979 unsigned long arg, int ifreq_len)
1980{
1981 struct tun_file *tfile = file->private_data;
1982 struct tun_struct *tun;
1983 void __user* argp = (void __user*)arg;
1984 struct ifreq ifr;
1985 kuid_t owner;
1986 kgid_t group;
1987 int sndbuf;
1988 int vnet_hdr_sz;
1989 unsigned int ifindex;
1990 int le;
1991 int ret;
1992
1993 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == SOCK_IOC_TYPE) {
1994 if (copy_from_user(&ifr, argp, ifreq_len))
1995 return -EFAULT;
1996 } else {
1997 memset(&ifr, 0, sizeof(ifr));
1998 }
1999 if (cmd == TUNGETFEATURES) {
2000 /* Currently this just means: "what IFF flags are valid?".
2001 * This is needed because we never checked for invalid flags on
2002 * TUNSETIFF.
2003 */
2004 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
2005 (unsigned int __user*)argp);
2006 } else if (cmd == TUNSETQUEUE)
2007 return tun_set_queue(file, &ifr);
2008
2009 ret = 0;
2010 rtnl_lock();
2011
2012 tun = __tun_get(tfile);
2013 if (cmd == TUNSETIFF) {
2014 ret = -EEXIST;
2015 if (tun)
2016 goto unlock;
2017
2018 ifr.ifr_name[IFNAMSIZ-1] = '\0';
2019
2020 ret = tun_set_iff(sock_net(&tfile->sk), file, &ifr);
2021
2022 if (ret)
2023 goto unlock;
2024
2025 if (copy_to_user(argp, &ifr, ifreq_len))
2026 ret = -EFAULT;
2027 goto unlock;
2028 }
2029 if (cmd == TUNSETIFINDEX) {
2030 ret = -EPERM;
2031 if (tun)
2032 goto unlock;
2033
2034 ret = -EFAULT;
2035 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
2036 goto unlock;
2037
2038 ret = 0;
2039 tfile->ifindex = ifindex;
2040 goto unlock;
2041 }
2042
2043 ret = -EBADFD;
2044 if (!tun)
2045 goto unlock;
2046
2047 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
2048
2049 ret = 0;
2050 switch (cmd) {
2051 case TUNGETIFF:
2052 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2053
2054 if (tfile->detached)
2055 ifr.ifr_flags |= IFF_DETACH_QUEUE;
2056 if (!tfile->socket.sk->sk_filter)
2057 ifr.ifr_flags |= IFF_NOFILTER;
2058
2059 if (copy_to_user(argp, &ifr, ifreq_len))
2060 ret = -EFAULT;
2061 break;
2062
2063 case TUNSETNOCSUM:
2064 /* Disable/Enable checksum */
2065
2066 /* [unimplemented] */
2067 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
2068 arg ? "disabled" : "enabled");
2069 break;
2070
2071 case TUNSETPERSIST:
2072 /* Disable/Enable persist mode. Keep an extra reference to the
2073 * module to prevent the module being unprobed.
2074 */
2075 if (arg && !(tun->flags & IFF_PERSIST)) {
2076 tun->flags |= IFF_PERSIST;
2077 __module_get(THIS_MODULE);
2078 }
2079 if (!arg && (tun->flags & IFF_PERSIST)) {
2080 tun->flags &= ~IFF_PERSIST;
2081 module_put(THIS_MODULE);
2082 }
2083
2084 tun_debug(KERN_INFO, tun, "persist %s\n",
2085 arg ? "enabled" : "disabled");
2086 break;
2087
2088 case TUNSETOWNER:
2089 /* Set owner of the device */
2090 owner = make_kuid(current_user_ns(), arg);
2091 if (!uid_valid(owner)) {
2092 ret = -EINVAL;
2093 break;
2094 }
2095 tun->owner = owner;
2096 tun_debug(KERN_INFO, tun, "owner set to %u\n",
2097 from_kuid(&init_user_ns, tun->owner));
2098 break;
2099
2100 case TUNSETGROUP:
2101 /* Set group of the device */
2102 group = make_kgid(current_user_ns(), arg);
2103 if (!gid_valid(group)) {
2104 ret = -EINVAL;
2105 break;
2106 }
2107 tun->group = group;
2108 tun_debug(KERN_INFO, tun, "group set to %u\n",
2109 from_kgid(&init_user_ns, tun->group));
2110 break;
2111
2112 case TUNSETLINK:
2113 /* Only allow setting the type when the interface is down */
2114 if (tun->dev->flags & IFF_UP) {
2115 tun_debug(KERN_INFO, tun,
2116 "Linktype set failed because interface is up\n");
2117 ret = -EBUSY;
2118 } else {
2119 tun->dev->type = (int) arg;
2120 tun_debug(KERN_INFO, tun, "linktype set to %d\n",
2121 tun->dev->type);
2122 ret = 0;
2123 }
2124 break;
2125
2126#ifdef TUN_DEBUG
2127 case TUNSETDEBUG:
2128 tun->debug = arg;
2129 break;
2130#endif
2131 case TUNSETOFFLOAD:
2132 ret = set_offload(tun, arg);
2133 break;
2134
2135 case TUNSETTXFILTER:
2136 /* Can be set only for TAPs */
2137 ret = -EINVAL;
2138 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2139 break;
2140 ret = update_filter(&tun->txflt, (void __user *)arg);
2141 break;
2142
2143 case SIOCGIFHWADDR:
2144 /* Get hw address */
2145 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
2146 ifr.ifr_hwaddr.sa_family = tun->dev->type;
2147 if (copy_to_user(argp, &ifr, ifreq_len))
2148 ret = -EFAULT;
2149 break;
2150
2151 case SIOCSIFHWADDR:
2152 /* Set hw address */
2153 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
2154 ifr.ifr_hwaddr.sa_data);
2155
2156 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
2157 break;
2158
2159 case TUNGETSNDBUF:
2160 sndbuf = tfile->socket.sk->sk_sndbuf;
2161 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
2162 ret = -EFAULT;
2163 break;
2164
2165 case TUNSETSNDBUF:
2166 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
2167 ret = -EFAULT;
2168 break;
2169 }
2170
2171 tun->sndbuf = sndbuf;
2172 tun_set_sndbuf(tun);
2173 break;
2174
2175 case TUNGETVNETHDRSZ:
2176 vnet_hdr_sz = tun->vnet_hdr_sz;
2177 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
2178 ret = -EFAULT;
2179 break;
2180
2181 case TUNSETVNETHDRSZ:
2182 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
2183 ret = -EFAULT;
2184 break;
2185 }
2186 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
2187 ret = -EINVAL;
2188 break;
2189 }
2190
2191 tun->vnet_hdr_sz = vnet_hdr_sz;
2192 break;
2193
2194 case TUNGETVNETLE:
2195 le = !!(tun->flags & TUN_VNET_LE);
2196 if (put_user(le, (int __user *)argp))
2197 ret = -EFAULT;
2198 break;
2199
2200 case TUNSETVNETLE:
2201 if (get_user(le, (int __user *)argp)) {
2202 ret = -EFAULT;
2203 break;
2204 }
2205 if (le)
2206 tun->flags |= TUN_VNET_LE;
2207 else
2208 tun->flags &= ~TUN_VNET_LE;
2209 break;
2210
2211 case TUNGETVNETBE:
2212 ret = tun_get_vnet_be(tun, argp);
2213 break;
2214
2215 case TUNSETVNETBE:
2216 ret = tun_set_vnet_be(tun, argp);
2217 break;
2218
2219 case TUNATTACHFILTER:
2220 /* Can be set only for TAPs */
2221 ret = -EINVAL;
2222 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2223 break;
2224 ret = -EFAULT;
2225 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
2226 break;
2227
2228 ret = tun_attach_filter(tun);
2229 break;
2230
2231 case TUNDETACHFILTER:
2232 /* Can be set only for TAPs */
2233 ret = -EINVAL;
2234 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2235 break;
2236 ret = 0;
2237 tun_detach_filter(tun, tun->numqueues);
2238 break;
2239
2240 case TUNGETFILTER:
2241 ret = -EINVAL;
2242 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2243 break;
2244 ret = -EFAULT;
2245 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
2246 break;
2247 ret = 0;
2248 break;
2249
2250 default:
2251 ret = -EINVAL;
2252 break;
2253 }
2254
2255unlock:
2256 rtnl_unlock();
2257 if (tun)
2258 tun_put(tun);
2259 return ret;
2260}
2261
2262static long tun_chr_ioctl(struct file *file,
2263 unsigned int cmd, unsigned long arg)
2264{
2265 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
2266}
2267
2268#ifdef CONFIG_COMPAT
2269static long tun_chr_compat_ioctl(struct file *file,
2270 unsigned int cmd, unsigned long arg)
2271{
2272 switch (cmd) {
2273 case TUNSETIFF:
2274 case TUNGETIFF:
2275 case TUNSETTXFILTER:
2276 case TUNGETSNDBUF:
2277 case TUNSETSNDBUF:
2278 case SIOCGIFHWADDR:
2279 case SIOCSIFHWADDR:
2280 arg = (unsigned long)compat_ptr(arg);
2281 break;
2282 default:
2283 arg = (compat_ulong_t)arg;
2284 break;
2285 }
2286
2287 /*
2288 * compat_ifreq is shorter than ifreq, so we must not access beyond
2289 * the end of that structure. All fields that are used in this
2290 * driver are compatible though, we don't need to convert the
2291 * contents.
2292 */
2293 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
2294}
2295#endif /* CONFIG_COMPAT */
2296
2297static int tun_chr_fasync(int fd, struct file *file, int on)
2298{
2299 struct tun_file *tfile = file->private_data;
2300 int ret;
2301
2302 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
2303 goto out;
2304
2305 if (on) {
2306 __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
2307 tfile->flags |= TUN_FASYNC;
2308 } else
2309 tfile->flags &= ~TUN_FASYNC;
2310 ret = 0;
2311out:
2312 return ret;
2313}
2314
2315static int tun_chr_open(struct inode *inode, struct file * file)
2316{
2317 struct net *net = current->nsproxy->net_ns;
2318 struct tun_file *tfile;
2319
2320 DBG1(KERN_INFO, "tunX: tun_chr_open\n");
2321
2322 tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
2323 &tun_proto, 0);
2324 if (!tfile)
2325 return -ENOMEM;
2326 RCU_INIT_POINTER(tfile->tun, NULL);
2327 tfile->flags = 0;
2328 tfile->ifindex = 0;
2329
2330 init_waitqueue_head(&tfile->wq.wait);
2331 RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq);
2332
2333 tfile->socket.file = file;
2334 tfile->socket.ops = &tun_socket_ops;
2335
2336 sock_init_data(&tfile->socket, &tfile->sk);
2337
2338 tfile->sk.sk_write_space = tun_sock_write_space;
2339 tfile->sk.sk_sndbuf = INT_MAX;
2340
2341 file->private_data = tfile;
2342 INIT_LIST_HEAD(&tfile->next);
2343
2344 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
2345
2346 return 0;
2347}
2348
2349static int tun_chr_close(struct inode *inode, struct file *file)
2350{
2351 struct tun_file *tfile = file->private_data;
2352
2353 tun_detach(tfile, true);
2354
2355 return 0;
2356}
2357
2358#ifdef CONFIG_PROC_FS
2359static void tun_chr_show_fdinfo(struct seq_file *m, struct file *f)
2360{
2361 struct tun_struct *tun;
2362 struct ifreq ifr;
2363
2364 memset(&ifr, 0, sizeof(ifr));
2365
2366 rtnl_lock();
2367 tun = tun_get(f);
2368 if (tun)
2369 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2370 rtnl_unlock();
2371
2372 if (tun)
2373 tun_put(tun);
2374
2375 seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
2376}
2377#endif
2378
2379static const struct file_operations tun_fops = {
2380 .owner = THIS_MODULE,
2381 .llseek = no_llseek,
2382 .read_iter = tun_chr_read_iter,
2383 .write_iter = tun_chr_write_iter,
2384 .poll = tun_chr_poll,
2385 .unlocked_ioctl = tun_chr_ioctl,
2386#ifdef CONFIG_COMPAT
2387 .compat_ioctl = tun_chr_compat_ioctl,
2388#endif
2389 .open = tun_chr_open,
2390 .release = tun_chr_close,
2391 .fasync = tun_chr_fasync,
2392#ifdef CONFIG_PROC_FS
2393 .show_fdinfo = tun_chr_show_fdinfo,
2394#endif
2395};
2396
2397static struct miscdevice tun_miscdev = {
2398 .minor = TUN_MINOR,
2399 .name = "tun",
2400 .nodename = "net/tun",
2401 .fops = &tun_fops,
2402};
2403
2404/* ethtool interface */
2405
2406static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
2407{
2408 cmd->supported = 0;
2409 cmd->advertising = 0;
2410 ethtool_cmd_speed_set(cmd, SPEED_10);
2411 cmd->duplex = DUPLEX_FULL;
2412 cmd->port = PORT_TP;
2413 cmd->phy_address = 0;
2414 cmd->transceiver = XCVR_INTERNAL;
2415 cmd->autoneg = AUTONEG_DISABLE;
2416 cmd->maxtxpkt = 0;
2417 cmd->maxrxpkt = 0;
2418 return 0;
2419}
2420
2421static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
2422{
2423 struct tun_struct *tun = netdev_priv(dev);
2424
2425 strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
2426 strlcpy(info->version, DRV_VERSION, sizeof(info->version));
2427
2428 switch (tun->flags & TUN_TYPE_MASK) {
2429 case IFF_TUN:
2430 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
2431 break;
2432 case IFF_TAP:
2433 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
2434 break;
2435 }
2436}
2437
2438static u32 tun_get_msglevel(struct net_device *dev)
2439{
2440#ifdef TUN_DEBUG
2441 struct tun_struct *tun = netdev_priv(dev);
2442 return tun->debug;
2443#else
2444 return -EOPNOTSUPP;
2445#endif
2446}
2447
2448static void tun_set_msglevel(struct net_device *dev, u32 value)
2449{
2450#ifdef TUN_DEBUG
2451 struct tun_struct *tun = netdev_priv(dev);
2452 tun->debug = value;
2453#endif
2454}
2455
2456static const struct ethtool_ops tun_ethtool_ops = {
2457 .get_settings = tun_get_settings,
2458 .get_drvinfo = tun_get_drvinfo,
2459 .get_msglevel = tun_get_msglevel,
2460 .set_msglevel = tun_set_msglevel,
2461 .get_link = ethtool_op_get_link,
2462 .get_ts_info = ethtool_op_get_ts_info,
2463};
2464
2465static int tun_queue_resize(struct tun_struct *tun)
2466{
2467 struct net_device *dev = tun->dev;
2468 struct tun_file *tfile;
2469 struct skb_array **arrays;
2470 int n = tun->numqueues + tun->numdisabled;
2471 int ret, i;
2472
2473 arrays = kmalloc(sizeof *arrays * n, GFP_KERNEL);
2474 if (!arrays)
2475 return -ENOMEM;
2476
2477 for (i = 0; i < tun->numqueues; i++) {
2478 tfile = rtnl_dereference(tun->tfiles[i]);
2479 arrays[i] = &tfile->tx_array;
2480 }
2481 list_for_each_entry(tfile, &tun->disabled, next)
2482 arrays[i++] = &tfile->tx_array;
2483
2484 ret = skb_array_resize_multiple(arrays, n,
2485 dev->tx_queue_len, GFP_KERNEL);
2486
2487 kfree(arrays);
2488 return ret;
2489}
2490
2491static int tun_device_event(struct notifier_block *unused,
2492 unsigned long event, void *ptr)
2493{
2494 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
2495 struct tun_struct *tun = netdev_priv(dev);
2496
2497 if (dev->rtnl_link_ops != &tun_link_ops)
2498 return NOTIFY_DONE;
2499
2500 switch (event) {
2501 case NETDEV_CHANGE_TX_QUEUE_LEN:
2502 if (tun_queue_resize(tun))
2503 return NOTIFY_BAD;
2504 break;
2505 default:
2506 break;
2507 }
2508
2509 return NOTIFY_DONE;
2510}
2511
2512static struct notifier_block tun_notifier_block __read_mostly = {
2513 .notifier_call = tun_device_event,
2514};
2515
2516static int __init tun_init(void)
2517{
2518 int ret = 0;
2519
2520 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
2521 pr_info("%s\n", DRV_COPYRIGHT);
2522
2523 ret = rtnl_link_register(&tun_link_ops);
2524 if (ret) {
2525 pr_err("Can't register link_ops\n");
2526 goto err_linkops;
2527 }
2528
2529 ret = misc_register(&tun_miscdev);
2530 if (ret) {
2531 pr_err("Can't register misc device %d\n", TUN_MINOR);
2532 goto err_misc;
2533 }
2534
2535 register_netdevice_notifier(&tun_notifier_block);
2536 return 0;
2537err_misc:
2538 rtnl_link_unregister(&tun_link_ops);
2539err_linkops:
2540 return ret;
2541}
2542
2543static void tun_cleanup(void)
2544{
2545 misc_deregister(&tun_miscdev);
2546 rtnl_link_unregister(&tun_link_ops);
2547 unregister_netdevice_notifier(&tun_notifier_block);
2548}
2549
2550/* Get an underlying socket object from tun file. Returns error unless file is
2551 * attached to a device. The returned object works like a packet socket, it
2552 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
2553 * holding a reference to the file for as long as the socket is in use. */
2554struct socket *tun_get_socket(struct file *file)
2555{
2556 struct tun_file *tfile;
2557 if (file->f_op != &tun_fops)
2558 return ERR_PTR(-EINVAL);
2559 tfile = file->private_data;
2560 if (!tfile)
2561 return ERR_PTR(-EBADFD);
2562 return &tfile->socket;
2563}
2564EXPORT_SYMBOL_GPL(tun_get_socket);
2565
2566module_init(tun_init);
2567module_exit(tun_cleanup);
2568MODULE_DESCRIPTION(DRV_DESCRIPTION);
2569MODULE_AUTHOR(DRV_COPYRIGHT);
2570MODULE_LICENSE("GPL");
2571MODULE_ALIAS_MISCDEV(TUN_MINOR);
2572MODULE_ALIAS("devname:net/tun");