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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/math.h>
58#include <linux/nsproxy.h>
59#include <linux/virtio_net.h>
60#include <linux/rcupdate.h>
61#include <net/net_namespace.h>
62#include <net/netns/generic.h>
63#include <net/rtnetlink.h>
64#include <net/sock.h>
65#include <net/xdp.h>
66#include <net/ip_tunnels.h>
67#include <linux/seq_file.h>
68#include <linux/uio.h>
69#include <linux/skb_array.h>
70#include <linux/bpf.h>
71#include <linux/bpf_trace.h>
72#include <linux/mutex.h>
73#include <linux/ieee802154.h>
74#include <uapi/linux/if_ltalk.h>
75#include <uapi/linux/if_fddi.h>
76#include <uapi/linux/if_hippi.h>
77#include <uapi/linux/if_fc.h>
78#include <net/ax25.h>
79#include <net/rose.h>
80#include <net/6lowpan.h>
81#include <net/rps.h>
82
83#include <linux/uaccess.h>
84#include <linux/proc_fs.h>
85
86static void tun_default_link_ksettings(struct net_device *dev,
87 struct ethtool_link_ksettings *cmd);
88
89#define TUN_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
90
91/* TUN device flags */
92
93/* IFF_ATTACH_QUEUE is never stored in device flags,
94 * overload it to mean fasync when stored there.
95 */
96#define TUN_FASYNC IFF_ATTACH_QUEUE
97/* High bits in flags field are unused. */
98#define TUN_VNET_LE 0x80000000
99#define TUN_VNET_BE 0x40000000
100
101#define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
102 IFF_MULTI_QUEUE | IFF_NAPI | IFF_NAPI_FRAGS)
103
104#define GOODCOPY_LEN 128
105
106#define FLT_EXACT_COUNT 8
107struct tap_filter {
108 unsigned int count; /* Number of addrs. Zero means disabled */
109 u32 mask[2]; /* Mask of the hashed addrs */
110 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
111};
112
113/* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
114 * to max number of VCPUs in guest. */
115#define MAX_TAP_QUEUES 256
116#define MAX_TAP_FLOWS 4096
117
118#define TUN_FLOW_EXPIRE (3 * HZ)
119
120/* A tun_file connects an open character device to a tuntap netdevice. It
121 * also contains all socket related structures (except sock_fprog and tap_filter)
122 * to serve as one transmit queue for tuntap device. The sock_fprog and
123 * tap_filter were kept in tun_struct since they were used for filtering for the
124 * netdevice not for a specific queue (at least I didn't see the requirement for
125 * this).
126 *
127 * RCU usage:
128 * The tun_file and tun_struct are loosely coupled, the pointer from one to the
129 * other can only be read while rcu_read_lock or rtnl_lock is held.
130 */
131struct tun_file {
132 struct sock sk;
133 struct socket socket;
134 struct tun_struct __rcu *tun;
135 struct fasync_struct *fasync;
136 /* only used for fasnyc */
137 unsigned int flags;
138 union {
139 u16 queue_index;
140 unsigned int ifindex;
141 };
142 struct napi_struct napi;
143 bool napi_enabled;
144 bool napi_frags_enabled;
145 struct mutex napi_mutex; /* Protects access to the above napi */
146 struct list_head next;
147 struct tun_struct *detached;
148 struct ptr_ring tx_ring;
149 struct xdp_rxq_info xdp_rxq;
150};
151
152struct tun_page {
153 struct page *page;
154 int count;
155};
156
157struct tun_flow_entry {
158 struct hlist_node hash_link;
159 struct rcu_head rcu;
160 struct tun_struct *tun;
161
162 u32 rxhash;
163 u32 rps_rxhash;
164 int queue_index;
165 unsigned long updated ____cacheline_aligned_in_smp;
166};
167
168#define TUN_NUM_FLOW_ENTRIES 1024
169#define TUN_MASK_FLOW_ENTRIES (TUN_NUM_FLOW_ENTRIES - 1)
170
171struct tun_prog {
172 struct rcu_head rcu;
173 struct bpf_prog *prog;
174};
175
176/* Since the socket were moved to tun_file, to preserve the behavior of persist
177 * device, socket filter, sndbuf and vnet header size were restore when the
178 * file were attached to a persist device.
179 */
180struct tun_struct {
181 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES];
182 unsigned int numqueues;
183 unsigned int flags;
184 kuid_t owner;
185 kgid_t group;
186
187 struct net_device *dev;
188 netdev_features_t set_features;
189#define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
190 NETIF_F_TSO6 | NETIF_F_GSO_UDP_L4)
191
192 int align;
193 int vnet_hdr_sz;
194 int sndbuf;
195 struct tap_filter txflt;
196 struct sock_fprog fprog;
197 /* protected by rtnl lock */
198 bool filter_attached;
199 u32 msg_enable;
200 spinlock_t lock;
201 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
202 struct timer_list flow_gc_timer;
203 unsigned long ageing_time;
204 unsigned int numdisabled;
205 struct list_head disabled;
206 void *security;
207 u32 flow_count;
208 u32 rx_batched;
209 atomic_long_t rx_frame_errors;
210 struct bpf_prog __rcu *xdp_prog;
211 struct tun_prog __rcu *steering_prog;
212 struct tun_prog __rcu *filter_prog;
213 struct ethtool_link_ksettings link_ksettings;
214 /* init args */
215 struct file *file;
216 struct ifreq *ifr;
217};
218
219struct veth {
220 __be16 h_vlan_proto;
221 __be16 h_vlan_TCI;
222};
223
224static void tun_flow_init(struct tun_struct *tun);
225static void tun_flow_uninit(struct tun_struct *tun);
226
227static int tun_napi_receive(struct napi_struct *napi, int budget)
228{
229 struct tun_file *tfile = container_of(napi, struct tun_file, napi);
230 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
231 struct sk_buff_head process_queue;
232 struct sk_buff *skb;
233 int received = 0;
234
235 __skb_queue_head_init(&process_queue);
236
237 spin_lock(&queue->lock);
238 skb_queue_splice_tail_init(queue, &process_queue);
239 spin_unlock(&queue->lock);
240
241 while (received < budget && (skb = __skb_dequeue(&process_queue))) {
242 napi_gro_receive(napi, skb);
243 ++received;
244 }
245
246 if (!skb_queue_empty(&process_queue)) {
247 spin_lock(&queue->lock);
248 skb_queue_splice(&process_queue, queue);
249 spin_unlock(&queue->lock);
250 }
251
252 return received;
253}
254
255static int tun_napi_poll(struct napi_struct *napi, int budget)
256{
257 unsigned int received;
258
259 received = tun_napi_receive(napi, budget);
260
261 if (received < budget)
262 napi_complete_done(napi, received);
263
264 return received;
265}
266
267static void tun_napi_init(struct tun_struct *tun, struct tun_file *tfile,
268 bool napi_en, bool napi_frags)
269{
270 tfile->napi_enabled = napi_en;
271 tfile->napi_frags_enabled = napi_en && napi_frags;
272 if (napi_en) {
273 netif_napi_add_tx(tun->dev, &tfile->napi, tun_napi_poll);
274 napi_enable(&tfile->napi);
275 }
276}
277
278static void tun_napi_enable(struct tun_file *tfile)
279{
280 if (tfile->napi_enabled)
281 napi_enable(&tfile->napi);
282}
283
284static void tun_napi_disable(struct tun_file *tfile)
285{
286 if (tfile->napi_enabled)
287 napi_disable(&tfile->napi);
288}
289
290static void tun_napi_del(struct tun_file *tfile)
291{
292 if (tfile->napi_enabled)
293 netif_napi_del(&tfile->napi);
294}
295
296static bool tun_napi_frags_enabled(const struct tun_file *tfile)
297{
298 return tfile->napi_frags_enabled;
299}
300
301#ifdef CONFIG_TUN_VNET_CROSS_LE
302static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
303{
304 return tun->flags & TUN_VNET_BE ? false :
305 virtio_legacy_is_little_endian();
306}
307
308static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
309{
310 int be = !!(tun->flags & TUN_VNET_BE);
311
312 if (put_user(be, argp))
313 return -EFAULT;
314
315 return 0;
316}
317
318static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
319{
320 int be;
321
322 if (get_user(be, argp))
323 return -EFAULT;
324
325 if (be)
326 tun->flags |= TUN_VNET_BE;
327 else
328 tun->flags &= ~TUN_VNET_BE;
329
330 return 0;
331}
332#else
333static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
334{
335 return virtio_legacy_is_little_endian();
336}
337
338static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
339{
340 return -EINVAL;
341}
342
343static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
344{
345 return -EINVAL;
346}
347#endif /* CONFIG_TUN_VNET_CROSS_LE */
348
349static inline bool tun_is_little_endian(struct tun_struct *tun)
350{
351 return tun->flags & TUN_VNET_LE ||
352 tun_legacy_is_little_endian(tun);
353}
354
355static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
356{
357 return __virtio16_to_cpu(tun_is_little_endian(tun), val);
358}
359
360static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
361{
362 return __cpu_to_virtio16(tun_is_little_endian(tun), val);
363}
364
365static inline u32 tun_hashfn(u32 rxhash)
366{
367 return rxhash & TUN_MASK_FLOW_ENTRIES;
368}
369
370static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
371{
372 struct tun_flow_entry *e;
373
374 hlist_for_each_entry_rcu(e, head, hash_link) {
375 if (e->rxhash == rxhash)
376 return e;
377 }
378 return NULL;
379}
380
381static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
382 struct hlist_head *head,
383 u32 rxhash, u16 queue_index)
384{
385 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
386
387 if (e) {
388 netif_info(tun, tx_queued, tun->dev,
389 "create flow: hash %u index %u\n",
390 rxhash, queue_index);
391 e->updated = jiffies;
392 e->rxhash = rxhash;
393 e->rps_rxhash = 0;
394 e->queue_index = queue_index;
395 e->tun = tun;
396 hlist_add_head_rcu(&e->hash_link, head);
397 ++tun->flow_count;
398 }
399 return e;
400}
401
402static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
403{
404 netif_info(tun, tx_queued, tun->dev, "delete flow: hash %u index %u\n",
405 e->rxhash, e->queue_index);
406 hlist_del_rcu(&e->hash_link);
407 kfree_rcu(e, rcu);
408 --tun->flow_count;
409}
410
411static void tun_flow_flush(struct tun_struct *tun)
412{
413 int i;
414
415 spin_lock_bh(&tun->lock);
416 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
417 struct tun_flow_entry *e;
418 struct hlist_node *n;
419
420 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
421 tun_flow_delete(tun, e);
422 }
423 spin_unlock_bh(&tun->lock);
424}
425
426static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
427{
428 int i;
429
430 spin_lock_bh(&tun->lock);
431 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
432 struct tun_flow_entry *e;
433 struct hlist_node *n;
434
435 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
436 if (e->queue_index == queue_index)
437 tun_flow_delete(tun, e);
438 }
439 }
440 spin_unlock_bh(&tun->lock);
441}
442
443static void tun_flow_cleanup(struct timer_list *t)
444{
445 struct tun_struct *tun = from_timer(tun, t, flow_gc_timer);
446 unsigned long delay = tun->ageing_time;
447 unsigned long next_timer = jiffies + delay;
448 unsigned long count = 0;
449 int i;
450
451 spin_lock(&tun->lock);
452 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
453 struct tun_flow_entry *e;
454 struct hlist_node *n;
455
456 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
457 unsigned long this_timer;
458
459 this_timer = e->updated + delay;
460 if (time_before_eq(this_timer, jiffies)) {
461 tun_flow_delete(tun, e);
462 continue;
463 }
464 count++;
465 if (time_before(this_timer, next_timer))
466 next_timer = this_timer;
467 }
468 }
469
470 if (count)
471 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
472 spin_unlock(&tun->lock);
473}
474
475static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
476 struct tun_file *tfile)
477{
478 struct hlist_head *head;
479 struct tun_flow_entry *e;
480 unsigned long delay = tun->ageing_time;
481 u16 queue_index = tfile->queue_index;
482
483 head = &tun->flows[tun_hashfn(rxhash)];
484
485 rcu_read_lock();
486
487 e = tun_flow_find(head, rxhash);
488 if (likely(e)) {
489 /* TODO: keep queueing to old queue until it's empty? */
490 if (READ_ONCE(e->queue_index) != queue_index)
491 WRITE_ONCE(e->queue_index, queue_index);
492 if (e->updated != jiffies)
493 e->updated = jiffies;
494 sock_rps_record_flow_hash(e->rps_rxhash);
495 } else {
496 spin_lock_bh(&tun->lock);
497 if (!tun_flow_find(head, rxhash) &&
498 tun->flow_count < MAX_TAP_FLOWS)
499 tun_flow_create(tun, head, rxhash, queue_index);
500
501 if (!timer_pending(&tun->flow_gc_timer))
502 mod_timer(&tun->flow_gc_timer,
503 round_jiffies_up(jiffies + delay));
504 spin_unlock_bh(&tun->lock);
505 }
506
507 rcu_read_unlock();
508}
509
510/* Save the hash received in the stack receive path and update the
511 * flow_hash table accordingly.
512 */
513static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
514{
515 if (unlikely(e->rps_rxhash != hash))
516 e->rps_rxhash = hash;
517}
518
519/* We try to identify a flow through its rxhash. The reason that
520 * we do not check rxq no. is because some cards(e.g 82599), chooses
521 * the rxq based on the txq where the last packet of the flow comes. As
522 * the userspace application move between processors, we may get a
523 * different rxq no. here.
524 */
525static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb)
526{
527 struct tun_flow_entry *e;
528 u32 txq, numqueues;
529
530 numqueues = READ_ONCE(tun->numqueues);
531
532 txq = __skb_get_hash_symmetric(skb);
533 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
534 if (e) {
535 tun_flow_save_rps_rxhash(e, txq);
536 txq = e->queue_index;
537 } else {
538 txq = reciprocal_scale(txq, numqueues);
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 spin_lock_init(&tun->lock);
982
983 err = security_tun_dev_alloc_security(&tun->security);
984 if (err < 0)
985 return err;
986
987 tun_flow_init(tun);
988
989 dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
990 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
991 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
992 NETIF_F_HW_VLAN_STAG_TX;
993 dev->features = dev->hw_features;
994 dev->vlan_features = dev->features &
995 ~(NETIF_F_HW_VLAN_CTAG_TX |
996 NETIF_F_HW_VLAN_STAG_TX);
997 dev->lltx = true;
998
999 tun->flags = (tun->flags & ~TUN_FEATURES) |
1000 (ifr->ifr_flags & TUN_FEATURES);
1001
1002 INIT_LIST_HEAD(&tun->disabled);
1003 err = tun_attach(tun, tun->file, false, ifr->ifr_flags & IFF_NAPI,
1004 ifr->ifr_flags & IFF_NAPI_FRAGS, false);
1005 if (err < 0) {
1006 tun_flow_uninit(tun);
1007 security_tun_dev_free_security(tun->security);
1008 return err;
1009 }
1010 return 0;
1011}
1012
1013/* Net device detach from fd. */
1014static void tun_net_uninit(struct net_device *dev)
1015{
1016 tun_detach_all(dev);
1017}
1018
1019/* Net device open. */
1020static int tun_net_open(struct net_device *dev)
1021{
1022 netif_tx_start_all_queues(dev);
1023
1024 return 0;
1025}
1026
1027/* Net device close. */
1028static int tun_net_close(struct net_device *dev)
1029{
1030 netif_tx_stop_all_queues(dev);
1031 return 0;
1032}
1033
1034/* Net device start xmit */
1035static void tun_automq_xmit(struct tun_struct *tun, struct sk_buff *skb)
1036{
1037#ifdef CONFIG_RPS
1038 if (tun->numqueues == 1 && static_branch_unlikely(&rps_needed)) {
1039 /* Select queue was not called for the skbuff, so we extract the
1040 * RPS hash and save it into the flow_table here.
1041 */
1042 struct tun_flow_entry *e;
1043 __u32 rxhash;
1044
1045 rxhash = __skb_get_hash_symmetric(skb);
1046 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)], rxhash);
1047 if (e)
1048 tun_flow_save_rps_rxhash(e, rxhash);
1049 }
1050#endif
1051}
1052
1053static unsigned int run_ebpf_filter(struct tun_struct *tun,
1054 struct sk_buff *skb,
1055 int len)
1056{
1057 struct tun_prog *prog = rcu_dereference(tun->filter_prog);
1058
1059 if (prog)
1060 len = bpf_prog_run_clear_cb(prog->prog, skb);
1061
1062 return len;
1063}
1064
1065/* Net device start xmit */
1066static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
1067{
1068 struct tun_struct *tun = netdev_priv(dev);
1069 enum skb_drop_reason drop_reason;
1070 int txq = skb->queue_mapping;
1071 struct netdev_queue *queue;
1072 struct tun_file *tfile;
1073 int len = skb->len;
1074
1075 rcu_read_lock();
1076 tfile = rcu_dereference(tun->tfiles[txq]);
1077
1078 /* Drop packet if interface is not attached */
1079 if (!tfile) {
1080 drop_reason = SKB_DROP_REASON_DEV_READY;
1081 goto drop;
1082 }
1083
1084 if (!rcu_dereference(tun->steering_prog))
1085 tun_automq_xmit(tun, skb);
1086
1087 netif_info(tun, tx_queued, tun->dev, "%s %d\n", __func__, skb->len);
1088
1089 /* Drop if the filter does not like it.
1090 * This is a noop if the filter is disabled.
1091 * Filter can be enabled only for the TAP devices. */
1092 if (!check_filter(&tun->txflt, skb)) {
1093 drop_reason = SKB_DROP_REASON_TAP_TXFILTER;
1094 goto drop;
1095 }
1096
1097 if (tfile->socket.sk->sk_filter &&
1098 sk_filter(tfile->socket.sk, skb)) {
1099 drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
1100 goto drop;
1101 }
1102
1103 len = run_ebpf_filter(tun, skb, len);
1104 if (len == 0) {
1105 drop_reason = SKB_DROP_REASON_TAP_FILTER;
1106 goto drop;
1107 }
1108
1109 if (pskb_trim(skb, len)) {
1110 drop_reason = SKB_DROP_REASON_NOMEM;
1111 goto drop;
1112 }
1113
1114 if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC))) {
1115 drop_reason = SKB_DROP_REASON_SKB_UCOPY_FAULT;
1116 goto drop;
1117 }
1118
1119 skb_tx_timestamp(skb);
1120
1121 /* Orphan the skb - required as we might hang on to it
1122 * for indefinite time.
1123 */
1124 skb_orphan(skb);
1125
1126 nf_reset_ct(skb);
1127
1128 if (ptr_ring_produce(&tfile->tx_ring, skb)) {
1129 drop_reason = SKB_DROP_REASON_FULL_RING;
1130 goto drop;
1131 }
1132
1133 /* dev->lltx requires to do our own update of trans_start */
1134 queue = netdev_get_tx_queue(dev, txq);
1135 txq_trans_cond_update(queue);
1136
1137 /* Notify and wake up reader process */
1138 if (tfile->flags & TUN_FASYNC)
1139 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1140 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1141
1142 rcu_read_unlock();
1143 return NETDEV_TX_OK;
1144
1145drop:
1146 dev_core_stats_tx_dropped_inc(dev);
1147 skb_tx_error(skb);
1148 kfree_skb_reason(skb, drop_reason);
1149 rcu_read_unlock();
1150 return NET_XMIT_DROP;
1151}
1152
1153static void tun_net_mclist(struct net_device *dev)
1154{
1155 /*
1156 * This callback is supposed to deal with mc filter in
1157 * _rx_ path and has nothing to do with the _tx_ path.
1158 * In rx path we always accept everything userspace gives us.
1159 */
1160}
1161
1162static netdev_features_t tun_net_fix_features(struct net_device *dev,
1163 netdev_features_t features)
1164{
1165 struct tun_struct *tun = netdev_priv(dev);
1166
1167 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
1168}
1169
1170static void tun_set_headroom(struct net_device *dev, int new_hr)
1171{
1172 struct tun_struct *tun = netdev_priv(dev);
1173
1174 if (new_hr < NET_SKB_PAD)
1175 new_hr = NET_SKB_PAD;
1176
1177 tun->align = new_hr;
1178}
1179
1180static void
1181tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
1182{
1183 struct tun_struct *tun = netdev_priv(dev);
1184
1185 dev_get_tstats64(dev, stats);
1186
1187 stats->rx_frame_errors +=
1188 (unsigned long)atomic_long_read(&tun->rx_frame_errors);
1189}
1190
1191static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1192 struct netlink_ext_ack *extack)
1193{
1194 struct tun_struct *tun = netdev_priv(dev);
1195 struct tun_file *tfile;
1196 struct bpf_prog *old_prog;
1197 int i;
1198
1199 old_prog = rtnl_dereference(tun->xdp_prog);
1200 rcu_assign_pointer(tun->xdp_prog, prog);
1201 if (old_prog)
1202 bpf_prog_put(old_prog);
1203
1204 for (i = 0; i < tun->numqueues; i++) {
1205 tfile = rtnl_dereference(tun->tfiles[i]);
1206 if (prog)
1207 sock_set_flag(&tfile->sk, SOCK_XDP);
1208 else
1209 sock_reset_flag(&tfile->sk, SOCK_XDP);
1210 }
1211 list_for_each_entry(tfile, &tun->disabled, next) {
1212 if (prog)
1213 sock_set_flag(&tfile->sk, SOCK_XDP);
1214 else
1215 sock_reset_flag(&tfile->sk, SOCK_XDP);
1216 }
1217
1218 return 0;
1219}
1220
1221static int tun_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1222{
1223 switch (xdp->command) {
1224 case XDP_SETUP_PROG:
1225 return tun_xdp_set(dev, xdp->prog, xdp->extack);
1226 default:
1227 return -EINVAL;
1228 }
1229}
1230
1231static int tun_net_change_carrier(struct net_device *dev, bool new_carrier)
1232{
1233 if (new_carrier) {
1234 struct tun_struct *tun = netdev_priv(dev);
1235
1236 if (!tun->numqueues)
1237 return -EPERM;
1238
1239 netif_carrier_on(dev);
1240 } else {
1241 netif_carrier_off(dev);
1242 }
1243 return 0;
1244}
1245
1246static const struct net_device_ops tun_netdev_ops = {
1247 .ndo_init = tun_net_init,
1248 .ndo_uninit = tun_net_uninit,
1249 .ndo_open = tun_net_open,
1250 .ndo_stop = tun_net_close,
1251 .ndo_start_xmit = tun_net_xmit,
1252 .ndo_fix_features = tun_net_fix_features,
1253 .ndo_select_queue = tun_select_queue,
1254 .ndo_set_rx_headroom = tun_set_headroom,
1255 .ndo_get_stats64 = tun_net_get_stats64,
1256 .ndo_change_carrier = tun_net_change_carrier,
1257};
1258
1259static void __tun_xdp_flush_tfile(struct tun_file *tfile)
1260{
1261 /* Notify and wake up reader process */
1262 if (tfile->flags & TUN_FASYNC)
1263 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1264 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1265}
1266
1267static int tun_xdp_xmit(struct net_device *dev, int n,
1268 struct xdp_frame **frames, u32 flags)
1269{
1270 struct tun_struct *tun = netdev_priv(dev);
1271 struct tun_file *tfile;
1272 u32 numqueues;
1273 int nxmit = 0;
1274 int i;
1275
1276 if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
1277 return -EINVAL;
1278
1279 rcu_read_lock();
1280
1281resample:
1282 numqueues = READ_ONCE(tun->numqueues);
1283 if (!numqueues) {
1284 rcu_read_unlock();
1285 return -ENXIO; /* Caller will free/return all frames */
1286 }
1287
1288 tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
1289 numqueues]);
1290 if (unlikely(!tfile))
1291 goto resample;
1292
1293 spin_lock(&tfile->tx_ring.producer_lock);
1294 for (i = 0; i < n; i++) {
1295 struct xdp_frame *xdp = frames[i];
1296 /* Encode the XDP flag into lowest bit for consumer to differ
1297 * XDP buffer from sk_buff.
1298 */
1299 void *frame = tun_xdp_to_ptr(xdp);
1300
1301 if (__ptr_ring_produce(&tfile->tx_ring, frame)) {
1302 dev_core_stats_tx_dropped_inc(dev);
1303 break;
1304 }
1305 nxmit++;
1306 }
1307 spin_unlock(&tfile->tx_ring.producer_lock);
1308
1309 if (flags & XDP_XMIT_FLUSH)
1310 __tun_xdp_flush_tfile(tfile);
1311
1312 rcu_read_unlock();
1313 return nxmit;
1314}
1315
1316static int tun_xdp_tx(struct net_device *dev, struct xdp_buff *xdp)
1317{
1318 struct xdp_frame *frame = xdp_convert_buff_to_frame(xdp);
1319 int nxmit;
1320
1321 if (unlikely(!frame))
1322 return -EOVERFLOW;
1323
1324 nxmit = tun_xdp_xmit(dev, 1, &frame, XDP_XMIT_FLUSH);
1325 if (!nxmit)
1326 xdp_return_frame_rx_napi(frame);
1327 return nxmit;
1328}
1329
1330static const struct net_device_ops tap_netdev_ops = {
1331 .ndo_init = tun_net_init,
1332 .ndo_uninit = tun_net_uninit,
1333 .ndo_open = tun_net_open,
1334 .ndo_stop = tun_net_close,
1335 .ndo_start_xmit = tun_net_xmit,
1336 .ndo_fix_features = tun_net_fix_features,
1337 .ndo_set_rx_mode = tun_net_mclist,
1338 .ndo_set_mac_address = eth_mac_addr,
1339 .ndo_validate_addr = eth_validate_addr,
1340 .ndo_select_queue = tun_select_queue,
1341 .ndo_features_check = passthru_features_check,
1342 .ndo_set_rx_headroom = tun_set_headroom,
1343 .ndo_bpf = tun_xdp,
1344 .ndo_xdp_xmit = tun_xdp_xmit,
1345 .ndo_change_carrier = tun_net_change_carrier,
1346};
1347
1348static void tun_flow_init(struct tun_struct *tun)
1349{
1350 int i;
1351
1352 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1353 INIT_HLIST_HEAD(&tun->flows[i]);
1354
1355 tun->ageing_time = TUN_FLOW_EXPIRE;
1356 timer_setup(&tun->flow_gc_timer, tun_flow_cleanup, 0);
1357 mod_timer(&tun->flow_gc_timer,
1358 round_jiffies_up(jiffies + tun->ageing_time));
1359}
1360
1361static void tun_flow_uninit(struct tun_struct *tun)
1362{
1363 del_timer_sync(&tun->flow_gc_timer);
1364 tun_flow_flush(tun);
1365}
1366
1367#define MIN_MTU 68
1368#define MAX_MTU 65535
1369
1370/* Initialize net device. */
1371static void tun_net_initialize(struct net_device *dev)
1372{
1373 struct tun_struct *tun = netdev_priv(dev);
1374
1375 switch (tun->flags & TUN_TYPE_MASK) {
1376 case IFF_TUN:
1377 dev->netdev_ops = &tun_netdev_ops;
1378 dev->header_ops = &ip_tunnel_header_ops;
1379
1380 /* Point-to-Point TUN Device */
1381 dev->hard_header_len = 0;
1382 dev->addr_len = 0;
1383 dev->mtu = 1500;
1384
1385 /* Zero header length */
1386 dev->type = ARPHRD_NONE;
1387 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1388 break;
1389
1390 case IFF_TAP:
1391 dev->netdev_ops = &tap_netdev_ops;
1392 /* Ethernet TAP Device */
1393 ether_setup(dev);
1394 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1395 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1396
1397 eth_hw_addr_random(dev);
1398
1399 /* Currently tun does not support XDP, only tap does. */
1400 dev->xdp_features = NETDEV_XDP_ACT_BASIC |
1401 NETDEV_XDP_ACT_REDIRECT |
1402 NETDEV_XDP_ACT_NDO_XMIT;
1403
1404 break;
1405 }
1406
1407 dev->min_mtu = MIN_MTU;
1408 dev->max_mtu = MAX_MTU - dev->hard_header_len;
1409}
1410
1411static bool tun_sock_writeable(struct tun_struct *tun, struct tun_file *tfile)
1412{
1413 struct sock *sk = tfile->socket.sk;
1414
1415 return (tun->dev->flags & IFF_UP) && sock_writeable(sk);
1416}
1417
1418/* Character device part */
1419
1420/* Poll */
1421static __poll_t tun_chr_poll(struct file *file, poll_table *wait)
1422{
1423 struct tun_file *tfile = file->private_data;
1424 struct tun_struct *tun = tun_get(tfile);
1425 struct sock *sk;
1426 __poll_t mask = 0;
1427
1428 if (!tun)
1429 return EPOLLERR;
1430
1431 sk = tfile->socket.sk;
1432
1433 poll_wait(file, sk_sleep(sk), wait);
1434
1435 if (!ptr_ring_empty(&tfile->tx_ring))
1436 mask |= EPOLLIN | EPOLLRDNORM;
1437
1438 /* Make sure SOCKWQ_ASYNC_NOSPACE is set if not writable to
1439 * guarantee EPOLLOUT to be raised by either here or
1440 * tun_sock_write_space(). Then process could get notification
1441 * after it writes to a down device and meets -EIO.
1442 */
1443 if (tun_sock_writeable(tun, tfile) ||
1444 (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1445 tun_sock_writeable(tun, tfile)))
1446 mask |= EPOLLOUT | EPOLLWRNORM;
1447
1448 if (tun->dev->reg_state != NETREG_REGISTERED)
1449 mask = EPOLLERR;
1450
1451 tun_put(tun);
1452 return mask;
1453}
1454
1455static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile,
1456 size_t len,
1457 const struct iov_iter *it)
1458{
1459 struct sk_buff *skb;
1460 size_t linear;
1461 int err;
1462 int i;
1463
1464 if (it->nr_segs > MAX_SKB_FRAGS + 1 ||
1465 len > (ETH_MAX_MTU - NET_SKB_PAD - NET_IP_ALIGN))
1466 return ERR_PTR(-EMSGSIZE);
1467
1468 local_bh_disable();
1469 skb = napi_get_frags(&tfile->napi);
1470 local_bh_enable();
1471 if (!skb)
1472 return ERR_PTR(-ENOMEM);
1473
1474 linear = iov_iter_single_seg_count(it);
1475 err = __skb_grow(skb, linear);
1476 if (err)
1477 goto free;
1478
1479 skb->len = len;
1480 skb->data_len = len - linear;
1481 skb->truesize += skb->data_len;
1482
1483 for (i = 1; i < it->nr_segs; i++) {
1484 const struct iovec *iov = iter_iov(it) + i;
1485 size_t fragsz = iov->iov_len;
1486 struct page *page;
1487 void *frag;
1488
1489 if (fragsz == 0 || fragsz > PAGE_SIZE) {
1490 err = -EINVAL;
1491 goto free;
1492 }
1493 frag = netdev_alloc_frag(fragsz);
1494 if (!frag) {
1495 err = -ENOMEM;
1496 goto free;
1497 }
1498 page = virt_to_head_page(frag);
1499 skb_fill_page_desc(skb, i - 1, page,
1500 frag - page_address(page), fragsz);
1501 }
1502
1503 return skb;
1504free:
1505 /* frees skb and all frags allocated with napi_alloc_frag() */
1506 napi_free_frags(&tfile->napi);
1507 return ERR_PTR(err);
1508}
1509
1510/* prepad is the amount to reserve at front. len is length after that.
1511 * linear is a hint as to how much to copy (usually headers). */
1512static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1513 size_t prepad, size_t len,
1514 size_t linear, int noblock)
1515{
1516 struct sock *sk = tfile->socket.sk;
1517 struct sk_buff *skb;
1518 int err;
1519
1520 /* Under a page? Don't bother with paged skb. */
1521 if (prepad + len < PAGE_SIZE)
1522 linear = len;
1523
1524 if (len - linear > MAX_SKB_FRAGS * (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER))
1525 linear = len - MAX_SKB_FRAGS * (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER);
1526 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1527 &err, PAGE_ALLOC_COSTLY_ORDER);
1528 if (!skb)
1529 return ERR_PTR(err);
1530
1531 skb_reserve(skb, prepad);
1532 skb_put(skb, linear);
1533 skb->data_len = len - linear;
1534 skb->len += len - linear;
1535
1536 return skb;
1537}
1538
1539static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile,
1540 struct sk_buff *skb, int more)
1541{
1542 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1543 struct sk_buff_head process_queue;
1544 u32 rx_batched = tun->rx_batched;
1545 bool rcv = false;
1546
1547 if (!rx_batched || (!more && skb_queue_empty(queue))) {
1548 local_bh_disable();
1549 skb_record_rx_queue(skb, tfile->queue_index);
1550 netif_receive_skb(skb);
1551 local_bh_enable();
1552 return;
1553 }
1554
1555 spin_lock(&queue->lock);
1556 if (!more || skb_queue_len(queue) == rx_batched) {
1557 __skb_queue_head_init(&process_queue);
1558 skb_queue_splice_tail_init(queue, &process_queue);
1559 rcv = true;
1560 } else {
1561 __skb_queue_tail(queue, skb);
1562 }
1563 spin_unlock(&queue->lock);
1564
1565 if (rcv) {
1566 struct sk_buff *nskb;
1567
1568 local_bh_disable();
1569 while ((nskb = __skb_dequeue(&process_queue))) {
1570 skb_record_rx_queue(nskb, tfile->queue_index);
1571 netif_receive_skb(nskb);
1572 }
1573 skb_record_rx_queue(skb, tfile->queue_index);
1574 netif_receive_skb(skb);
1575 local_bh_enable();
1576 }
1577}
1578
1579static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile,
1580 int len, int noblock, bool zerocopy)
1581{
1582 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
1583 return false;
1584
1585 if (tfile->socket.sk->sk_sndbuf != INT_MAX)
1586 return false;
1587
1588 if (!noblock)
1589 return false;
1590
1591 if (zerocopy)
1592 return false;
1593
1594 if (SKB_DATA_ALIGN(len + TUN_RX_PAD + XDP_PACKET_HEADROOM) +
1595 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
1596 return false;
1597
1598 return true;
1599}
1600
1601static struct sk_buff *__tun_build_skb(struct tun_file *tfile,
1602 struct page_frag *alloc_frag, char *buf,
1603 int buflen, int len, int pad)
1604{
1605 struct sk_buff *skb = build_skb(buf, buflen);
1606
1607 if (!skb)
1608 return ERR_PTR(-ENOMEM);
1609
1610 skb_reserve(skb, pad);
1611 skb_put(skb, len);
1612 skb_set_owner_w(skb, tfile->socket.sk);
1613
1614 get_page(alloc_frag->page);
1615 alloc_frag->offset += buflen;
1616
1617 return skb;
1618}
1619
1620static int tun_xdp_act(struct tun_struct *tun, struct bpf_prog *xdp_prog,
1621 struct xdp_buff *xdp, u32 act)
1622{
1623 int err;
1624
1625 switch (act) {
1626 case XDP_REDIRECT:
1627 err = xdp_do_redirect(tun->dev, xdp, xdp_prog);
1628 if (err) {
1629 dev_core_stats_rx_dropped_inc(tun->dev);
1630 return err;
1631 }
1632 dev_sw_netstats_rx_add(tun->dev, xdp->data_end - xdp->data);
1633 break;
1634 case XDP_TX:
1635 err = tun_xdp_tx(tun->dev, xdp);
1636 if (err < 0) {
1637 dev_core_stats_rx_dropped_inc(tun->dev);
1638 return err;
1639 }
1640 dev_sw_netstats_rx_add(tun->dev, xdp->data_end - xdp->data);
1641 break;
1642 case XDP_PASS:
1643 break;
1644 default:
1645 bpf_warn_invalid_xdp_action(tun->dev, xdp_prog, act);
1646 fallthrough;
1647 case XDP_ABORTED:
1648 trace_xdp_exception(tun->dev, xdp_prog, act);
1649 fallthrough;
1650 case XDP_DROP:
1651 dev_core_stats_rx_dropped_inc(tun->dev);
1652 break;
1653 }
1654
1655 return act;
1656}
1657
1658static struct sk_buff *tun_build_skb(struct tun_struct *tun,
1659 struct tun_file *tfile,
1660 struct iov_iter *from,
1661 struct virtio_net_hdr *hdr,
1662 int len, int *skb_xdp)
1663{
1664 struct page_frag *alloc_frag = ¤t->task_frag;
1665 struct bpf_net_context __bpf_net_ctx, *bpf_net_ctx;
1666 struct bpf_prog *xdp_prog;
1667 int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1668 char *buf;
1669 size_t copied;
1670 int pad = TUN_RX_PAD;
1671 int err = 0;
1672
1673 rcu_read_lock();
1674 xdp_prog = rcu_dereference(tun->xdp_prog);
1675 if (xdp_prog)
1676 pad += XDP_PACKET_HEADROOM;
1677 buflen += SKB_DATA_ALIGN(len + pad);
1678 rcu_read_unlock();
1679
1680 alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES);
1681 if (unlikely(!skb_page_frag_refill(buflen, alloc_frag, GFP_KERNEL)))
1682 return ERR_PTR(-ENOMEM);
1683
1684 buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
1685 copied = copy_page_from_iter(alloc_frag->page,
1686 alloc_frag->offset + pad,
1687 len, from);
1688 if (copied != len)
1689 return ERR_PTR(-EFAULT);
1690
1691 /* There's a small window that XDP may be set after the check
1692 * of xdp_prog above, this should be rare and for simplicity
1693 * we do XDP on skb in case the headroom is not enough.
1694 */
1695 if (hdr->gso_type || !xdp_prog) {
1696 *skb_xdp = 1;
1697 return __tun_build_skb(tfile, alloc_frag, buf, buflen, len,
1698 pad);
1699 }
1700
1701 *skb_xdp = 0;
1702
1703 local_bh_disable();
1704 rcu_read_lock();
1705 bpf_net_ctx = bpf_net_ctx_set(&__bpf_net_ctx);
1706 xdp_prog = rcu_dereference(tun->xdp_prog);
1707 if (xdp_prog) {
1708 struct xdp_buff xdp;
1709 u32 act;
1710
1711 xdp_init_buff(&xdp, buflen, &tfile->xdp_rxq);
1712 xdp_prepare_buff(&xdp, buf, pad, len, false);
1713
1714 act = bpf_prog_run_xdp(xdp_prog, &xdp);
1715 if (act == XDP_REDIRECT || act == XDP_TX) {
1716 get_page(alloc_frag->page);
1717 alloc_frag->offset += buflen;
1718 }
1719 err = tun_xdp_act(tun, xdp_prog, &xdp, act);
1720 if (err < 0) {
1721 if (act == XDP_REDIRECT || act == XDP_TX)
1722 put_page(alloc_frag->page);
1723 goto out;
1724 }
1725
1726 if (err == XDP_REDIRECT)
1727 xdp_do_flush();
1728 if (err != XDP_PASS)
1729 goto out;
1730
1731 pad = xdp.data - xdp.data_hard_start;
1732 len = xdp.data_end - xdp.data;
1733 }
1734 bpf_net_ctx_clear(bpf_net_ctx);
1735 rcu_read_unlock();
1736 local_bh_enable();
1737
1738 return __tun_build_skb(tfile, alloc_frag, buf, buflen, len, pad);
1739
1740out:
1741 bpf_net_ctx_clear(bpf_net_ctx);
1742 rcu_read_unlock();
1743 local_bh_enable();
1744 return NULL;
1745}
1746
1747/* Get packet from user space buffer */
1748static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1749 void *msg_control, struct iov_iter *from,
1750 int noblock, bool more)
1751{
1752 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1753 struct sk_buff *skb;
1754 size_t total_len = iov_iter_count(from);
1755 size_t len = total_len, align = tun->align, linear;
1756 struct virtio_net_hdr gso = { 0 };
1757 int good_linear;
1758 int copylen;
1759 bool zerocopy = false;
1760 int err;
1761 u32 rxhash = 0;
1762 int skb_xdp = 1;
1763 bool frags = tun_napi_frags_enabled(tfile);
1764 enum skb_drop_reason drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
1765
1766 if (!(tun->flags & IFF_NO_PI)) {
1767 if (len < sizeof(pi))
1768 return -EINVAL;
1769 len -= sizeof(pi);
1770
1771 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1772 return -EFAULT;
1773 }
1774
1775 if (tun->flags & IFF_VNET_HDR) {
1776 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1777
1778 if (len < vnet_hdr_sz)
1779 return -EINVAL;
1780 len -= vnet_hdr_sz;
1781
1782 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1783 return -EFAULT;
1784
1785 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1786 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1787 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1788
1789 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1790 return -EINVAL;
1791 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1792 }
1793
1794 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1795 align += NET_IP_ALIGN;
1796 if (unlikely(len < ETH_HLEN ||
1797 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1798 return -EINVAL;
1799 }
1800
1801 good_linear = SKB_MAX_HEAD(align);
1802
1803 if (msg_control) {
1804 struct iov_iter i = *from;
1805
1806 /* There are 256 bytes to be copied in skb, so there is
1807 * enough room for skb expand head in case it is used.
1808 * The rest of the buffer is mapped from userspace.
1809 */
1810 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1811 if (copylen > good_linear)
1812 copylen = good_linear;
1813 linear = copylen;
1814 iov_iter_advance(&i, copylen);
1815 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1816 zerocopy = true;
1817 }
1818
1819 if (!frags && tun_can_build_skb(tun, tfile, len, noblock, zerocopy)) {
1820 /* For the packet that is not easy to be processed
1821 * (e.g gso or jumbo packet), we will do it at after
1822 * skb was created with generic XDP routine.
1823 */
1824 skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp);
1825 err = PTR_ERR_OR_ZERO(skb);
1826 if (err)
1827 goto drop;
1828 if (!skb)
1829 return total_len;
1830 } else {
1831 if (!zerocopy) {
1832 copylen = len;
1833 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1834 linear = good_linear;
1835 else
1836 linear = tun16_to_cpu(tun, gso.hdr_len);
1837 }
1838
1839 if (frags) {
1840 mutex_lock(&tfile->napi_mutex);
1841 skb = tun_napi_alloc_frags(tfile, copylen, from);
1842 /* tun_napi_alloc_frags() enforces a layout for the skb.
1843 * If zerocopy is enabled, then this layout will be
1844 * overwritten by zerocopy_sg_from_iter().
1845 */
1846 zerocopy = false;
1847 } else {
1848 if (!linear)
1849 linear = min_t(size_t, good_linear, copylen);
1850
1851 skb = tun_alloc_skb(tfile, align, copylen, linear,
1852 noblock);
1853 }
1854
1855 err = PTR_ERR_OR_ZERO(skb);
1856 if (err)
1857 goto drop;
1858
1859 if (zerocopy)
1860 err = zerocopy_sg_from_iter(skb, from);
1861 else
1862 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1863
1864 if (err) {
1865 err = -EFAULT;
1866 drop_reason = SKB_DROP_REASON_SKB_UCOPY_FAULT;
1867 goto drop;
1868 }
1869 }
1870
1871 if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1872 atomic_long_inc(&tun->rx_frame_errors);
1873 err = -EINVAL;
1874 goto free_skb;
1875 }
1876
1877 switch (tun->flags & TUN_TYPE_MASK) {
1878 case IFF_TUN:
1879 if (tun->flags & IFF_NO_PI) {
1880 u8 ip_version = skb->len ? (skb->data[0] >> 4) : 0;
1881
1882 switch (ip_version) {
1883 case 4:
1884 pi.proto = htons(ETH_P_IP);
1885 break;
1886 case 6:
1887 pi.proto = htons(ETH_P_IPV6);
1888 break;
1889 default:
1890 err = -EINVAL;
1891 goto drop;
1892 }
1893 }
1894
1895 skb_reset_mac_header(skb);
1896 skb->protocol = pi.proto;
1897 skb->dev = tun->dev;
1898 break;
1899 case IFF_TAP:
1900 if (frags && !pskb_may_pull(skb, ETH_HLEN)) {
1901 err = -ENOMEM;
1902 drop_reason = SKB_DROP_REASON_HDR_TRUNC;
1903 goto drop;
1904 }
1905 skb->protocol = eth_type_trans(skb, tun->dev);
1906 break;
1907 }
1908
1909 /* copy skb_ubuf_info for callback when skb has no error */
1910 if (zerocopy) {
1911 skb_zcopy_init(skb, msg_control);
1912 } else if (msg_control) {
1913 struct ubuf_info *uarg = msg_control;
1914 uarg->ops->complete(NULL, uarg, false);
1915 }
1916
1917 skb_reset_network_header(skb);
1918 skb_probe_transport_header(skb);
1919 skb_record_rx_queue(skb, tfile->queue_index);
1920
1921 if (skb_xdp) {
1922 struct bpf_prog *xdp_prog;
1923 int ret;
1924
1925 local_bh_disable();
1926 rcu_read_lock();
1927 xdp_prog = rcu_dereference(tun->xdp_prog);
1928 if (xdp_prog) {
1929 ret = do_xdp_generic(xdp_prog, &skb);
1930 if (ret != XDP_PASS) {
1931 rcu_read_unlock();
1932 local_bh_enable();
1933 goto unlock_frags;
1934 }
1935 }
1936 rcu_read_unlock();
1937 local_bh_enable();
1938 }
1939
1940 /* Compute the costly rx hash only if needed for flow updates.
1941 * We may get a very small possibility of OOO during switching, not
1942 * worth to optimize.
1943 */
1944 if (!rcu_access_pointer(tun->steering_prog) && tun->numqueues > 1 &&
1945 !tfile->detached)
1946 rxhash = __skb_get_hash_symmetric(skb);
1947
1948 rcu_read_lock();
1949 if (unlikely(!(tun->dev->flags & IFF_UP))) {
1950 err = -EIO;
1951 rcu_read_unlock();
1952 drop_reason = SKB_DROP_REASON_DEV_READY;
1953 goto drop;
1954 }
1955
1956 if (frags) {
1957 u32 headlen;
1958
1959 /* Exercise flow dissector code path. */
1960 skb_push(skb, ETH_HLEN);
1961 headlen = eth_get_headlen(tun->dev, skb->data,
1962 skb_headlen(skb));
1963
1964 if (unlikely(headlen > skb_headlen(skb))) {
1965 WARN_ON_ONCE(1);
1966 err = -ENOMEM;
1967 dev_core_stats_rx_dropped_inc(tun->dev);
1968napi_busy:
1969 napi_free_frags(&tfile->napi);
1970 rcu_read_unlock();
1971 mutex_unlock(&tfile->napi_mutex);
1972 return err;
1973 }
1974
1975 if (likely(napi_schedule_prep(&tfile->napi))) {
1976 local_bh_disable();
1977 napi_gro_frags(&tfile->napi);
1978 napi_complete(&tfile->napi);
1979 local_bh_enable();
1980 } else {
1981 err = -EBUSY;
1982 goto napi_busy;
1983 }
1984 mutex_unlock(&tfile->napi_mutex);
1985 } else if (tfile->napi_enabled) {
1986 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1987 int queue_len;
1988
1989 spin_lock_bh(&queue->lock);
1990
1991 if (unlikely(tfile->detached)) {
1992 spin_unlock_bh(&queue->lock);
1993 rcu_read_unlock();
1994 err = -EBUSY;
1995 goto free_skb;
1996 }
1997
1998 __skb_queue_tail(queue, skb);
1999 queue_len = skb_queue_len(queue);
2000 spin_unlock(&queue->lock);
2001
2002 if (!more || queue_len > NAPI_POLL_WEIGHT)
2003 napi_schedule(&tfile->napi);
2004
2005 local_bh_enable();
2006 } else if (!IS_ENABLED(CONFIG_4KSTACKS)) {
2007 tun_rx_batched(tun, tfile, skb, more);
2008 } else {
2009 netif_rx(skb);
2010 }
2011 rcu_read_unlock();
2012
2013 preempt_disable();
2014 dev_sw_netstats_rx_add(tun->dev, len);
2015 preempt_enable();
2016
2017 if (rxhash)
2018 tun_flow_update(tun, rxhash, tfile);
2019
2020 return total_len;
2021
2022drop:
2023 if (err != -EAGAIN)
2024 dev_core_stats_rx_dropped_inc(tun->dev);
2025
2026free_skb:
2027 if (!IS_ERR_OR_NULL(skb))
2028 kfree_skb_reason(skb, drop_reason);
2029
2030unlock_frags:
2031 if (frags) {
2032 tfile->napi.skb = NULL;
2033 mutex_unlock(&tfile->napi_mutex);
2034 }
2035
2036 return err ?: total_len;
2037}
2038
2039static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
2040{
2041 struct file *file = iocb->ki_filp;
2042 struct tun_file *tfile = file->private_data;
2043 struct tun_struct *tun = tun_get(tfile);
2044 ssize_t result;
2045 int noblock = 0;
2046
2047 if (!tun)
2048 return -EBADFD;
2049
2050 if ((file->f_flags & O_NONBLOCK) || (iocb->ki_flags & IOCB_NOWAIT))
2051 noblock = 1;
2052
2053 result = tun_get_user(tun, tfile, NULL, from, noblock, false);
2054
2055 tun_put(tun);
2056 return result;
2057}
2058
2059static ssize_t tun_put_user_xdp(struct tun_struct *tun,
2060 struct tun_file *tfile,
2061 struct xdp_frame *xdp_frame,
2062 struct iov_iter *iter)
2063{
2064 int vnet_hdr_sz = 0;
2065 size_t size = xdp_frame->len;
2066 size_t ret;
2067
2068 if (tun->flags & IFF_VNET_HDR) {
2069 struct virtio_net_hdr gso = { 0 };
2070
2071 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2072 if (unlikely(iov_iter_count(iter) < vnet_hdr_sz))
2073 return -EINVAL;
2074 if (unlikely(copy_to_iter(&gso, sizeof(gso), iter) !=
2075 sizeof(gso)))
2076 return -EFAULT;
2077 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2078 }
2079
2080 ret = copy_to_iter(xdp_frame->data, size, iter) + vnet_hdr_sz;
2081
2082 preempt_disable();
2083 dev_sw_netstats_tx_add(tun->dev, 1, ret);
2084 preempt_enable();
2085
2086 return ret;
2087}
2088
2089/* Put packet to the user space buffer */
2090static ssize_t tun_put_user(struct tun_struct *tun,
2091 struct tun_file *tfile,
2092 struct sk_buff *skb,
2093 struct iov_iter *iter)
2094{
2095 struct tun_pi pi = { 0, skb->protocol };
2096 ssize_t total;
2097 int vlan_offset = 0;
2098 int vlan_hlen = 0;
2099 int vnet_hdr_sz = 0;
2100
2101 if (skb_vlan_tag_present(skb))
2102 vlan_hlen = VLAN_HLEN;
2103
2104 if (tun->flags & IFF_VNET_HDR)
2105 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2106
2107 total = skb->len + vlan_hlen + vnet_hdr_sz;
2108
2109 if (!(tun->flags & IFF_NO_PI)) {
2110 if (iov_iter_count(iter) < sizeof(pi))
2111 return -EINVAL;
2112
2113 total += sizeof(pi);
2114 if (iov_iter_count(iter) < total) {
2115 /* Packet will be striped */
2116 pi.flags |= TUN_PKT_STRIP;
2117 }
2118
2119 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
2120 return -EFAULT;
2121 }
2122
2123 if (vnet_hdr_sz) {
2124 struct virtio_net_hdr gso;
2125
2126 if (iov_iter_count(iter) < vnet_hdr_sz)
2127 return -EINVAL;
2128
2129 if (virtio_net_hdr_from_skb(skb, &gso,
2130 tun_is_little_endian(tun), true,
2131 vlan_hlen)) {
2132 struct skb_shared_info *sinfo = skb_shinfo(skb);
2133
2134 if (net_ratelimit()) {
2135 netdev_err(tun->dev, "unexpected GSO type: 0x%x, gso_size %d, hdr_len %d\n",
2136 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
2137 tun16_to_cpu(tun, gso.hdr_len));
2138 print_hex_dump(KERN_ERR, "tun: ",
2139 DUMP_PREFIX_NONE,
2140 16, 1, skb->head,
2141 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
2142 }
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 tun_flow_uninit(tun);
2322 security_tun_dev_free_security(tun->security);
2323 __tun_set_ebpf(tun, &tun->steering_prog, NULL);
2324 __tun_set_ebpf(tun, &tun->filter_prog, NULL);
2325}
2326
2327static void tun_setup(struct net_device *dev)
2328{
2329 struct tun_struct *tun = netdev_priv(dev);
2330
2331 tun->owner = INVALID_UID;
2332 tun->group = INVALID_GID;
2333 tun_default_link_ksettings(dev, &tun->link_ksettings);
2334
2335 dev->ethtool_ops = &tun_ethtool_ops;
2336 dev->needs_free_netdev = true;
2337 dev->priv_destructor = tun_free_netdev;
2338 /* We prefer our own queue length */
2339 dev->tx_queue_len = TUN_READQ_SIZE;
2340}
2341
2342/* Trivial set of netlink ops to allow deleting tun or tap
2343 * device with netlink.
2344 */
2345static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
2346 struct netlink_ext_ack *extack)
2347{
2348 NL_SET_ERR_MSG(extack,
2349 "tun/tap creation via rtnetlink is not supported.");
2350 return -EOPNOTSUPP;
2351}
2352
2353static size_t tun_get_size(const struct net_device *dev)
2354{
2355 BUILD_BUG_ON(sizeof(u32) != sizeof(uid_t));
2356 BUILD_BUG_ON(sizeof(u32) != sizeof(gid_t));
2357
2358 return nla_total_size(sizeof(uid_t)) + /* OWNER */
2359 nla_total_size(sizeof(gid_t)) + /* GROUP */
2360 nla_total_size(sizeof(u8)) + /* TYPE */
2361 nla_total_size(sizeof(u8)) + /* PI */
2362 nla_total_size(sizeof(u8)) + /* VNET_HDR */
2363 nla_total_size(sizeof(u8)) + /* PERSIST */
2364 nla_total_size(sizeof(u8)) + /* MULTI_QUEUE */
2365 nla_total_size(sizeof(u32)) + /* NUM_QUEUES */
2366 nla_total_size(sizeof(u32)) + /* NUM_DISABLED_QUEUES */
2367 0;
2368}
2369
2370static int tun_fill_info(struct sk_buff *skb, const struct net_device *dev)
2371{
2372 struct tun_struct *tun = netdev_priv(dev);
2373
2374 if (nla_put_u8(skb, IFLA_TUN_TYPE, tun->flags & TUN_TYPE_MASK))
2375 goto nla_put_failure;
2376 if (uid_valid(tun->owner) &&
2377 nla_put_u32(skb, IFLA_TUN_OWNER,
2378 from_kuid_munged(current_user_ns(), tun->owner)))
2379 goto nla_put_failure;
2380 if (gid_valid(tun->group) &&
2381 nla_put_u32(skb, IFLA_TUN_GROUP,
2382 from_kgid_munged(current_user_ns(), tun->group)))
2383 goto nla_put_failure;
2384 if (nla_put_u8(skb, IFLA_TUN_PI, !(tun->flags & IFF_NO_PI)))
2385 goto nla_put_failure;
2386 if (nla_put_u8(skb, IFLA_TUN_VNET_HDR, !!(tun->flags & IFF_VNET_HDR)))
2387 goto nla_put_failure;
2388 if (nla_put_u8(skb, IFLA_TUN_PERSIST, !!(tun->flags & IFF_PERSIST)))
2389 goto nla_put_failure;
2390 if (nla_put_u8(skb, IFLA_TUN_MULTI_QUEUE,
2391 !!(tun->flags & IFF_MULTI_QUEUE)))
2392 goto nla_put_failure;
2393 if (tun->flags & IFF_MULTI_QUEUE) {
2394 if (nla_put_u32(skb, IFLA_TUN_NUM_QUEUES, tun->numqueues))
2395 goto nla_put_failure;
2396 if (nla_put_u32(skb, IFLA_TUN_NUM_DISABLED_QUEUES,
2397 tun->numdisabled))
2398 goto nla_put_failure;
2399 }
2400
2401 return 0;
2402
2403nla_put_failure:
2404 return -EMSGSIZE;
2405}
2406
2407static struct rtnl_link_ops tun_link_ops __read_mostly = {
2408 .kind = DRV_NAME,
2409 .priv_size = sizeof(struct tun_struct),
2410 .setup = tun_setup,
2411 .validate = tun_validate,
2412 .get_size = tun_get_size,
2413 .fill_info = tun_fill_info,
2414};
2415
2416static void tun_sock_write_space(struct sock *sk)
2417{
2418 struct tun_file *tfile;
2419 wait_queue_head_t *wqueue;
2420
2421 if (!sock_writeable(sk))
2422 return;
2423
2424 if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
2425 return;
2426
2427 wqueue = sk_sleep(sk);
2428 if (wqueue && waitqueue_active(wqueue))
2429 wake_up_interruptible_sync_poll(wqueue, EPOLLOUT |
2430 EPOLLWRNORM | EPOLLWRBAND);
2431
2432 tfile = container_of(sk, struct tun_file, sk);
2433 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
2434}
2435
2436static void tun_put_page(struct tun_page *tpage)
2437{
2438 if (tpage->page)
2439 __page_frag_cache_drain(tpage->page, tpage->count);
2440}
2441
2442static int tun_xdp_one(struct tun_struct *tun,
2443 struct tun_file *tfile,
2444 struct xdp_buff *xdp, int *flush,
2445 struct tun_page *tpage)
2446{
2447 unsigned int datasize = xdp->data_end - xdp->data;
2448 struct tun_xdp_hdr *hdr = xdp->data_hard_start;
2449 struct virtio_net_hdr *gso = &hdr->gso;
2450 struct bpf_prog *xdp_prog;
2451 struct sk_buff *skb = NULL;
2452 struct sk_buff_head *queue;
2453 u32 rxhash = 0, act;
2454 int buflen = hdr->buflen;
2455 int ret = 0;
2456 bool skb_xdp = false;
2457 struct page *page;
2458
2459 if (unlikely(datasize < ETH_HLEN))
2460 return -EINVAL;
2461
2462 xdp_prog = rcu_dereference(tun->xdp_prog);
2463 if (xdp_prog) {
2464 if (gso->gso_type) {
2465 skb_xdp = true;
2466 goto build;
2467 }
2468
2469 xdp_init_buff(xdp, buflen, &tfile->xdp_rxq);
2470 xdp_set_data_meta_invalid(xdp);
2471
2472 act = bpf_prog_run_xdp(xdp_prog, xdp);
2473 ret = tun_xdp_act(tun, xdp_prog, xdp, act);
2474 if (ret < 0) {
2475 put_page(virt_to_head_page(xdp->data));
2476 return ret;
2477 }
2478
2479 switch (ret) {
2480 case XDP_REDIRECT:
2481 *flush = true;
2482 fallthrough;
2483 case XDP_TX:
2484 return 0;
2485 case XDP_PASS:
2486 break;
2487 default:
2488 page = virt_to_head_page(xdp->data);
2489 if (tpage->page == page) {
2490 ++tpage->count;
2491 } else {
2492 tun_put_page(tpage);
2493 tpage->page = page;
2494 tpage->count = 1;
2495 }
2496 return 0;
2497 }
2498 }
2499
2500build:
2501 skb = build_skb(xdp->data_hard_start, buflen);
2502 if (!skb) {
2503 ret = -ENOMEM;
2504 goto out;
2505 }
2506
2507 skb_reserve(skb, xdp->data - xdp->data_hard_start);
2508 skb_put(skb, xdp->data_end - xdp->data);
2509
2510 if (virtio_net_hdr_to_skb(skb, gso, tun_is_little_endian(tun))) {
2511 atomic_long_inc(&tun->rx_frame_errors);
2512 kfree_skb(skb);
2513 ret = -EINVAL;
2514 goto out;
2515 }
2516
2517 skb->protocol = eth_type_trans(skb, tun->dev);
2518 skb_reset_network_header(skb);
2519 skb_probe_transport_header(skb);
2520 skb_record_rx_queue(skb, tfile->queue_index);
2521
2522 if (skb_xdp) {
2523 ret = do_xdp_generic(xdp_prog, &skb);
2524 if (ret != XDP_PASS) {
2525 ret = 0;
2526 goto out;
2527 }
2528 }
2529
2530 if (!rcu_dereference(tun->steering_prog) && tun->numqueues > 1 &&
2531 !tfile->detached)
2532 rxhash = __skb_get_hash_symmetric(skb);
2533
2534 if (tfile->napi_enabled) {
2535 queue = &tfile->sk.sk_write_queue;
2536 spin_lock(&queue->lock);
2537
2538 if (unlikely(tfile->detached)) {
2539 spin_unlock(&queue->lock);
2540 kfree_skb(skb);
2541 return -EBUSY;
2542 }
2543
2544 __skb_queue_tail(queue, skb);
2545 spin_unlock(&queue->lock);
2546 ret = 1;
2547 } else {
2548 netif_receive_skb(skb);
2549 ret = 0;
2550 }
2551
2552 /* No need to disable preemption here since this function is
2553 * always called with bh disabled
2554 */
2555 dev_sw_netstats_rx_add(tun->dev, datasize);
2556
2557 if (rxhash)
2558 tun_flow_update(tun, rxhash, tfile);
2559
2560out:
2561 return ret;
2562}
2563
2564static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
2565{
2566 int ret, i;
2567 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2568 struct tun_struct *tun = tun_get(tfile);
2569 struct tun_msg_ctl *ctl = m->msg_control;
2570 struct xdp_buff *xdp;
2571
2572 if (!tun)
2573 return -EBADFD;
2574
2575 if (m->msg_controllen == sizeof(struct tun_msg_ctl) &&
2576 ctl && ctl->type == TUN_MSG_PTR) {
2577 struct bpf_net_context __bpf_net_ctx, *bpf_net_ctx;
2578 struct tun_page tpage;
2579 int n = ctl->num;
2580 int flush = 0, queued = 0;
2581
2582 memset(&tpage, 0, sizeof(tpage));
2583
2584 local_bh_disable();
2585 rcu_read_lock();
2586 bpf_net_ctx = bpf_net_ctx_set(&__bpf_net_ctx);
2587
2588 for (i = 0; i < n; i++) {
2589 xdp = &((struct xdp_buff *)ctl->ptr)[i];
2590 ret = tun_xdp_one(tun, tfile, xdp, &flush, &tpage);
2591 if (ret > 0)
2592 queued += ret;
2593 }
2594
2595 if (flush)
2596 xdp_do_flush();
2597
2598 if (tfile->napi_enabled && queued > 0)
2599 napi_schedule(&tfile->napi);
2600
2601 bpf_net_ctx_clear(bpf_net_ctx);
2602 rcu_read_unlock();
2603 local_bh_enable();
2604
2605 tun_put_page(&tpage);
2606
2607 ret = total_len;
2608 goto out;
2609 }
2610
2611 ret = tun_get_user(tun, tfile, ctl ? ctl->ptr : NULL, &m->msg_iter,
2612 m->msg_flags & MSG_DONTWAIT,
2613 m->msg_flags & MSG_MORE);
2614out:
2615 tun_put(tun);
2616 return ret;
2617}
2618
2619static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
2620 int flags)
2621{
2622 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2623 struct tun_struct *tun = tun_get(tfile);
2624 void *ptr = m->msg_control;
2625 int ret;
2626
2627 if (!tun) {
2628 ret = -EBADFD;
2629 goto out_free;
2630 }
2631
2632 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
2633 ret = -EINVAL;
2634 goto out_put_tun;
2635 }
2636 if (flags & MSG_ERRQUEUE) {
2637 ret = sock_recv_errqueue(sock->sk, m, total_len,
2638 SOL_PACKET, TUN_TX_TIMESTAMP);
2639 goto out;
2640 }
2641 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT, ptr);
2642 if (ret > (ssize_t)total_len) {
2643 m->msg_flags |= MSG_TRUNC;
2644 ret = flags & MSG_TRUNC ? ret : total_len;
2645 }
2646out:
2647 tun_put(tun);
2648 return ret;
2649
2650out_put_tun:
2651 tun_put(tun);
2652out_free:
2653 tun_ptr_free(ptr);
2654 return ret;
2655}
2656
2657static int tun_ptr_peek_len(void *ptr)
2658{
2659 if (likely(ptr)) {
2660 if (tun_is_xdp_frame(ptr)) {
2661 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
2662
2663 return xdpf->len;
2664 }
2665 return __skb_array_len_with_tag(ptr);
2666 } else {
2667 return 0;
2668 }
2669}
2670
2671static int tun_peek_len(struct socket *sock)
2672{
2673 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2674 struct tun_struct *tun;
2675 int ret = 0;
2676
2677 tun = tun_get(tfile);
2678 if (!tun)
2679 return 0;
2680
2681 ret = PTR_RING_PEEK_CALL(&tfile->tx_ring, tun_ptr_peek_len);
2682 tun_put(tun);
2683
2684 return ret;
2685}
2686
2687/* Ops structure to mimic raw sockets with tun */
2688static const struct proto_ops tun_socket_ops = {
2689 .peek_len = tun_peek_len,
2690 .sendmsg = tun_sendmsg,
2691 .recvmsg = tun_recvmsg,
2692};
2693
2694static struct proto tun_proto = {
2695 .name = "tun",
2696 .owner = THIS_MODULE,
2697 .obj_size = sizeof(struct tun_file),
2698};
2699
2700static int tun_flags(struct tun_struct *tun)
2701{
2702 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
2703}
2704
2705static ssize_t tun_flags_show(struct device *dev, struct device_attribute *attr,
2706 char *buf)
2707{
2708 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2709 return sysfs_emit(buf, "0x%x\n", tun_flags(tun));
2710}
2711
2712static ssize_t owner_show(struct device *dev, struct device_attribute *attr,
2713 char *buf)
2714{
2715 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2716 return uid_valid(tun->owner)?
2717 sysfs_emit(buf, "%u\n",
2718 from_kuid_munged(current_user_ns(), tun->owner)) :
2719 sysfs_emit(buf, "-1\n");
2720}
2721
2722static ssize_t group_show(struct device *dev, struct device_attribute *attr,
2723 char *buf)
2724{
2725 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2726 return gid_valid(tun->group) ?
2727 sysfs_emit(buf, "%u\n",
2728 from_kgid_munged(current_user_ns(), tun->group)) :
2729 sysfs_emit(buf, "-1\n");
2730}
2731
2732static DEVICE_ATTR_RO(tun_flags);
2733static DEVICE_ATTR_RO(owner);
2734static DEVICE_ATTR_RO(group);
2735
2736static struct attribute *tun_dev_attrs[] = {
2737 &dev_attr_tun_flags.attr,
2738 &dev_attr_owner.attr,
2739 &dev_attr_group.attr,
2740 NULL
2741};
2742
2743static const struct attribute_group tun_attr_group = {
2744 .attrs = tun_dev_attrs
2745};
2746
2747static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
2748{
2749 struct tun_struct *tun;
2750 struct tun_file *tfile = file->private_data;
2751 struct net_device *dev;
2752 int err;
2753
2754 if (tfile->detached)
2755 return -EINVAL;
2756
2757 if ((ifr->ifr_flags & IFF_NAPI_FRAGS)) {
2758 if (!capable(CAP_NET_ADMIN))
2759 return -EPERM;
2760
2761 if (!(ifr->ifr_flags & IFF_NAPI) ||
2762 (ifr->ifr_flags & TUN_TYPE_MASK) != IFF_TAP)
2763 return -EINVAL;
2764 }
2765
2766 dev = __dev_get_by_name(net, ifr->ifr_name);
2767 if (dev) {
2768 if (ifr->ifr_flags & IFF_TUN_EXCL)
2769 return -EBUSY;
2770 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
2771 tun = netdev_priv(dev);
2772 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
2773 tun = netdev_priv(dev);
2774 else
2775 return -EINVAL;
2776
2777 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
2778 !!(tun->flags & IFF_MULTI_QUEUE))
2779 return -EINVAL;
2780
2781 if (tun_not_capable(tun))
2782 return -EPERM;
2783 err = security_tun_dev_open(tun->security);
2784 if (err < 0)
2785 return err;
2786
2787 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER,
2788 ifr->ifr_flags & IFF_NAPI,
2789 ifr->ifr_flags & IFF_NAPI_FRAGS, true);
2790 if (err < 0)
2791 return err;
2792
2793 if (tun->flags & IFF_MULTI_QUEUE &&
2794 (tun->numqueues + tun->numdisabled > 1)) {
2795 /* One or more queue has already been attached, no need
2796 * to initialize the device again.
2797 */
2798 netdev_state_change(dev);
2799 return 0;
2800 }
2801
2802 tun->flags = (tun->flags & ~TUN_FEATURES) |
2803 (ifr->ifr_flags & TUN_FEATURES);
2804
2805 netdev_state_change(dev);
2806 } else {
2807 char *name;
2808 unsigned long flags = 0;
2809 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
2810 MAX_TAP_QUEUES : 1;
2811
2812 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2813 return -EPERM;
2814 err = security_tun_dev_create();
2815 if (err < 0)
2816 return err;
2817
2818 /* Set dev type */
2819 if (ifr->ifr_flags & IFF_TUN) {
2820 /* TUN device */
2821 flags |= IFF_TUN;
2822 name = "tun%d";
2823 } else if (ifr->ifr_flags & IFF_TAP) {
2824 /* TAP device */
2825 flags |= IFF_TAP;
2826 name = "tap%d";
2827 } else
2828 return -EINVAL;
2829
2830 if (*ifr->ifr_name)
2831 name = ifr->ifr_name;
2832
2833 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
2834 NET_NAME_UNKNOWN, tun_setup, queues,
2835 queues);
2836
2837 if (!dev)
2838 return -ENOMEM;
2839
2840 dev_net_set(dev, net);
2841 dev->rtnl_link_ops = &tun_link_ops;
2842 dev->ifindex = tfile->ifindex;
2843 dev->sysfs_groups[0] = &tun_attr_group;
2844
2845 tun = netdev_priv(dev);
2846 tun->dev = dev;
2847 tun->flags = flags;
2848 tun->txflt.count = 0;
2849 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
2850
2851 tun->align = NET_SKB_PAD;
2852 tun->filter_attached = false;
2853 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
2854 tun->rx_batched = 0;
2855 RCU_INIT_POINTER(tun->steering_prog, NULL);
2856
2857 tun->ifr = ifr;
2858 tun->file = file;
2859
2860 tun_net_initialize(dev);
2861
2862 err = register_netdevice(tun->dev);
2863 if (err < 0) {
2864 free_netdev(dev);
2865 return err;
2866 }
2867 /* free_netdev() won't check refcnt, to avoid race
2868 * with dev_put() we need publish tun after registration.
2869 */
2870 rcu_assign_pointer(tfile->tun, tun);
2871 }
2872
2873 if (ifr->ifr_flags & IFF_NO_CARRIER)
2874 netif_carrier_off(tun->dev);
2875 else
2876 netif_carrier_on(tun->dev);
2877
2878 /* Make sure persistent devices do not get stuck in
2879 * xoff state.
2880 */
2881 if (netif_running(tun->dev))
2882 netif_tx_wake_all_queues(tun->dev);
2883
2884 strcpy(ifr->ifr_name, tun->dev->name);
2885 return 0;
2886}
2887
2888static void tun_get_iff(struct tun_struct *tun, struct ifreq *ifr)
2889{
2890 strcpy(ifr->ifr_name, tun->dev->name);
2891
2892 ifr->ifr_flags = tun_flags(tun);
2893
2894}
2895
2896/* This is like a cut-down ethtool ops, except done via tun fd so no
2897 * privs required. */
2898static int set_offload(struct tun_struct *tun, unsigned long arg)
2899{
2900 netdev_features_t features = 0;
2901
2902 if (arg & TUN_F_CSUM) {
2903 features |= NETIF_F_HW_CSUM;
2904 arg &= ~TUN_F_CSUM;
2905
2906 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
2907 if (arg & TUN_F_TSO_ECN) {
2908 features |= NETIF_F_TSO_ECN;
2909 arg &= ~TUN_F_TSO_ECN;
2910 }
2911 if (arg & TUN_F_TSO4)
2912 features |= NETIF_F_TSO;
2913 if (arg & TUN_F_TSO6)
2914 features |= NETIF_F_TSO6;
2915 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
2916 }
2917
2918 arg &= ~TUN_F_UFO;
2919
2920 /* TODO: for now USO4 and USO6 should work simultaneously */
2921 if (arg & TUN_F_USO4 && arg & TUN_F_USO6) {
2922 features |= NETIF_F_GSO_UDP_L4;
2923 arg &= ~(TUN_F_USO4 | TUN_F_USO6);
2924 }
2925 }
2926
2927 /* This gives the user a way to test for new features in future by
2928 * trying to set them. */
2929 if (arg)
2930 return -EINVAL;
2931
2932 tun->set_features = features;
2933 tun->dev->wanted_features &= ~TUN_USER_FEATURES;
2934 tun->dev->wanted_features |= features;
2935 netdev_update_features(tun->dev);
2936
2937 return 0;
2938}
2939
2940static void tun_detach_filter(struct tun_struct *tun, int n)
2941{
2942 int i;
2943 struct tun_file *tfile;
2944
2945 for (i = 0; i < n; i++) {
2946 tfile = rtnl_dereference(tun->tfiles[i]);
2947 lock_sock(tfile->socket.sk);
2948 sk_detach_filter(tfile->socket.sk);
2949 release_sock(tfile->socket.sk);
2950 }
2951
2952 tun->filter_attached = false;
2953}
2954
2955static int tun_attach_filter(struct tun_struct *tun)
2956{
2957 int i, ret = 0;
2958 struct tun_file *tfile;
2959
2960 for (i = 0; i < tun->numqueues; i++) {
2961 tfile = rtnl_dereference(tun->tfiles[i]);
2962 lock_sock(tfile->socket.sk);
2963 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
2964 release_sock(tfile->socket.sk);
2965 if (ret) {
2966 tun_detach_filter(tun, i);
2967 return ret;
2968 }
2969 }
2970
2971 tun->filter_attached = true;
2972 return ret;
2973}
2974
2975static void tun_set_sndbuf(struct tun_struct *tun)
2976{
2977 struct tun_file *tfile;
2978 int i;
2979
2980 for (i = 0; i < tun->numqueues; i++) {
2981 tfile = rtnl_dereference(tun->tfiles[i]);
2982 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
2983 }
2984}
2985
2986static int tun_set_queue(struct file *file, struct ifreq *ifr)
2987{
2988 struct tun_file *tfile = file->private_data;
2989 struct tun_struct *tun;
2990 int ret = 0;
2991
2992 rtnl_lock();
2993
2994 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
2995 tun = tfile->detached;
2996 if (!tun) {
2997 ret = -EINVAL;
2998 goto unlock;
2999 }
3000 ret = security_tun_dev_attach_queue(tun->security);
3001 if (ret < 0)
3002 goto unlock;
3003 ret = tun_attach(tun, file, false, tun->flags & IFF_NAPI,
3004 tun->flags & IFF_NAPI_FRAGS, true);
3005 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
3006 tun = rtnl_dereference(tfile->tun);
3007 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
3008 ret = -EINVAL;
3009 else
3010 __tun_detach(tfile, false);
3011 } else
3012 ret = -EINVAL;
3013
3014 if (ret >= 0)
3015 netdev_state_change(tun->dev);
3016
3017unlock:
3018 rtnl_unlock();
3019 return ret;
3020}
3021
3022static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog __rcu **prog_p,
3023 void __user *data)
3024{
3025 struct bpf_prog *prog;
3026 int fd;
3027
3028 if (copy_from_user(&fd, data, sizeof(fd)))
3029 return -EFAULT;
3030
3031 if (fd == -1) {
3032 prog = NULL;
3033 } else {
3034 prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
3035 if (IS_ERR(prog))
3036 return PTR_ERR(prog);
3037 }
3038
3039 return __tun_set_ebpf(tun, prog_p, prog);
3040}
3041
3042/* Return correct value for tun->dev->addr_len based on tun->dev->type. */
3043static unsigned char tun_get_addr_len(unsigned short type)
3044{
3045 switch (type) {
3046 case ARPHRD_IP6GRE:
3047 case ARPHRD_TUNNEL6:
3048 return sizeof(struct in6_addr);
3049 case ARPHRD_IPGRE:
3050 case ARPHRD_TUNNEL:
3051 case ARPHRD_SIT:
3052 return 4;
3053 case ARPHRD_ETHER:
3054 return ETH_ALEN;
3055 case ARPHRD_IEEE802154:
3056 case ARPHRD_IEEE802154_MONITOR:
3057 return IEEE802154_EXTENDED_ADDR_LEN;
3058 case ARPHRD_PHONET_PIPE:
3059 case ARPHRD_PPP:
3060 case ARPHRD_NONE:
3061 return 0;
3062 case ARPHRD_6LOWPAN:
3063 return EUI64_ADDR_LEN;
3064 case ARPHRD_FDDI:
3065 return FDDI_K_ALEN;
3066 case ARPHRD_HIPPI:
3067 return HIPPI_ALEN;
3068 case ARPHRD_IEEE802:
3069 return FC_ALEN;
3070 case ARPHRD_ROSE:
3071 return ROSE_ADDR_LEN;
3072 case ARPHRD_NETROM:
3073 return AX25_ADDR_LEN;
3074 case ARPHRD_LOCALTLK:
3075 return LTALK_ALEN;
3076 default:
3077 return 0;
3078 }
3079}
3080
3081static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
3082 unsigned long arg, int ifreq_len)
3083{
3084 struct tun_file *tfile = file->private_data;
3085 struct net *net = sock_net(&tfile->sk);
3086 struct tun_struct *tun;
3087 void __user* argp = (void __user*)arg;
3088 unsigned int carrier;
3089 struct ifreq ifr;
3090 kuid_t owner;
3091 kgid_t group;
3092 int ifindex;
3093 int sndbuf;
3094 int vnet_hdr_sz;
3095 int le;
3096 int ret;
3097 bool do_notify = false;
3098
3099 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE ||
3100 (_IOC_TYPE(cmd) == SOCK_IOC_TYPE && cmd != SIOCGSKNS)) {
3101 if (copy_from_user(&ifr, argp, ifreq_len))
3102 return -EFAULT;
3103 } else {
3104 memset(&ifr, 0, sizeof(ifr));
3105 }
3106 if (cmd == TUNGETFEATURES) {
3107 /* Currently this just means: "what IFF flags are valid?".
3108 * This is needed because we never checked for invalid flags on
3109 * TUNSETIFF.
3110 */
3111 return put_user(IFF_TUN | IFF_TAP | IFF_NO_CARRIER |
3112 TUN_FEATURES, (unsigned int __user*)argp);
3113 } else if (cmd == TUNSETQUEUE) {
3114 return tun_set_queue(file, &ifr);
3115 } else if (cmd == SIOCGSKNS) {
3116 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3117 return -EPERM;
3118 return open_related_ns(&net->ns, get_net_ns);
3119 }
3120
3121 rtnl_lock();
3122
3123 tun = tun_get(tfile);
3124 if (cmd == TUNSETIFF) {
3125 ret = -EEXIST;
3126 if (tun)
3127 goto unlock;
3128
3129 ifr.ifr_name[IFNAMSIZ-1] = '\0';
3130
3131 ret = tun_set_iff(net, file, &ifr);
3132
3133 if (ret)
3134 goto unlock;
3135
3136 if (copy_to_user(argp, &ifr, ifreq_len))
3137 ret = -EFAULT;
3138 goto unlock;
3139 }
3140 if (cmd == TUNSETIFINDEX) {
3141 ret = -EPERM;
3142 if (tun)
3143 goto unlock;
3144
3145 ret = -EFAULT;
3146 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
3147 goto unlock;
3148 ret = -EINVAL;
3149 if (ifindex < 0)
3150 goto unlock;
3151 ret = 0;
3152 tfile->ifindex = ifindex;
3153 goto unlock;
3154 }
3155
3156 ret = -EBADFD;
3157 if (!tun)
3158 goto unlock;
3159
3160 netif_info(tun, drv, tun->dev, "tun_chr_ioctl cmd %u\n", cmd);
3161
3162 net = dev_net(tun->dev);
3163 ret = 0;
3164 switch (cmd) {
3165 case TUNGETIFF:
3166 tun_get_iff(tun, &ifr);
3167
3168 if (tfile->detached)
3169 ifr.ifr_flags |= IFF_DETACH_QUEUE;
3170 if (!tfile->socket.sk->sk_filter)
3171 ifr.ifr_flags |= IFF_NOFILTER;
3172
3173 if (copy_to_user(argp, &ifr, ifreq_len))
3174 ret = -EFAULT;
3175 break;
3176
3177 case TUNSETNOCSUM:
3178 /* Disable/Enable checksum */
3179
3180 /* [unimplemented] */
3181 netif_info(tun, drv, tun->dev, "ignored: set checksum %s\n",
3182 arg ? "disabled" : "enabled");
3183 break;
3184
3185 case TUNSETPERSIST:
3186 /* Disable/Enable persist mode. Keep an extra reference to the
3187 * module to prevent the module being unprobed.
3188 */
3189 if (arg && !(tun->flags & IFF_PERSIST)) {
3190 tun->flags |= IFF_PERSIST;
3191 __module_get(THIS_MODULE);
3192 do_notify = true;
3193 }
3194 if (!arg && (tun->flags & IFF_PERSIST)) {
3195 tun->flags &= ~IFF_PERSIST;
3196 module_put(THIS_MODULE);
3197 do_notify = true;
3198 }
3199
3200 netif_info(tun, drv, tun->dev, "persist %s\n",
3201 arg ? "enabled" : "disabled");
3202 break;
3203
3204 case TUNSETOWNER:
3205 /* Set owner of the device */
3206 owner = make_kuid(current_user_ns(), arg);
3207 if (!uid_valid(owner)) {
3208 ret = -EINVAL;
3209 break;
3210 }
3211 tun->owner = owner;
3212 do_notify = true;
3213 netif_info(tun, drv, tun->dev, "owner set to %u\n",
3214 from_kuid(&init_user_ns, tun->owner));
3215 break;
3216
3217 case TUNSETGROUP:
3218 /* Set group of the device */
3219 group = make_kgid(current_user_ns(), arg);
3220 if (!gid_valid(group)) {
3221 ret = -EINVAL;
3222 break;
3223 }
3224 tun->group = group;
3225 do_notify = true;
3226 netif_info(tun, drv, tun->dev, "group set to %u\n",
3227 from_kgid(&init_user_ns, tun->group));
3228 break;
3229
3230 case TUNSETLINK:
3231 /* Only allow setting the type when the interface is down */
3232 if (tun->dev->flags & IFF_UP) {
3233 netif_info(tun, drv, tun->dev,
3234 "Linktype set failed because interface is up\n");
3235 ret = -EBUSY;
3236 } else {
3237 ret = call_netdevice_notifiers(NETDEV_PRE_TYPE_CHANGE,
3238 tun->dev);
3239 ret = notifier_to_errno(ret);
3240 if (ret) {
3241 netif_info(tun, drv, tun->dev,
3242 "Refused to change device type\n");
3243 break;
3244 }
3245 tun->dev->type = (int) arg;
3246 tun->dev->addr_len = tun_get_addr_len(tun->dev->type);
3247 netif_info(tun, drv, tun->dev, "linktype set to %d\n",
3248 tun->dev->type);
3249 call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE,
3250 tun->dev);
3251 }
3252 break;
3253
3254 case TUNSETDEBUG:
3255 tun->msg_enable = (u32)arg;
3256 break;
3257
3258 case TUNSETOFFLOAD:
3259 ret = set_offload(tun, arg);
3260 break;
3261
3262 case TUNSETTXFILTER:
3263 /* Can be set only for TAPs */
3264 ret = -EINVAL;
3265 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3266 break;
3267 ret = update_filter(&tun->txflt, (void __user *)arg);
3268 break;
3269
3270 case SIOCGIFHWADDR:
3271 /* Get hw address */
3272 dev_get_mac_address(&ifr.ifr_hwaddr, net, tun->dev->name);
3273 if (copy_to_user(argp, &ifr, ifreq_len))
3274 ret = -EFAULT;
3275 break;
3276
3277 case SIOCSIFHWADDR:
3278 /* Set hw address */
3279 ret = dev_set_mac_address_user(tun->dev, &ifr.ifr_hwaddr, NULL);
3280 break;
3281
3282 case TUNGETSNDBUF:
3283 sndbuf = tfile->socket.sk->sk_sndbuf;
3284 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
3285 ret = -EFAULT;
3286 break;
3287
3288 case TUNSETSNDBUF:
3289 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
3290 ret = -EFAULT;
3291 break;
3292 }
3293 if (sndbuf <= 0) {
3294 ret = -EINVAL;
3295 break;
3296 }
3297
3298 tun->sndbuf = sndbuf;
3299 tun_set_sndbuf(tun);
3300 break;
3301
3302 case TUNGETVNETHDRSZ:
3303 vnet_hdr_sz = tun->vnet_hdr_sz;
3304 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
3305 ret = -EFAULT;
3306 break;
3307
3308 case TUNSETVNETHDRSZ:
3309 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
3310 ret = -EFAULT;
3311 break;
3312 }
3313 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
3314 ret = -EINVAL;
3315 break;
3316 }
3317
3318 tun->vnet_hdr_sz = vnet_hdr_sz;
3319 break;
3320
3321 case TUNGETVNETLE:
3322 le = !!(tun->flags & TUN_VNET_LE);
3323 if (put_user(le, (int __user *)argp))
3324 ret = -EFAULT;
3325 break;
3326
3327 case TUNSETVNETLE:
3328 if (get_user(le, (int __user *)argp)) {
3329 ret = -EFAULT;
3330 break;
3331 }
3332 if (le)
3333 tun->flags |= TUN_VNET_LE;
3334 else
3335 tun->flags &= ~TUN_VNET_LE;
3336 break;
3337
3338 case TUNGETVNETBE:
3339 ret = tun_get_vnet_be(tun, argp);
3340 break;
3341
3342 case TUNSETVNETBE:
3343 ret = tun_set_vnet_be(tun, argp);
3344 break;
3345
3346 case TUNATTACHFILTER:
3347 /* Can be set only for TAPs */
3348 ret = -EINVAL;
3349 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3350 break;
3351 ret = -EFAULT;
3352 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
3353 break;
3354
3355 ret = tun_attach_filter(tun);
3356 break;
3357
3358 case TUNDETACHFILTER:
3359 /* Can be set only for TAPs */
3360 ret = -EINVAL;
3361 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3362 break;
3363 ret = 0;
3364 tun_detach_filter(tun, tun->numqueues);
3365 break;
3366
3367 case TUNGETFILTER:
3368 ret = -EINVAL;
3369 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3370 break;
3371 ret = -EFAULT;
3372 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
3373 break;
3374 ret = 0;
3375 break;
3376
3377 case TUNSETSTEERINGEBPF:
3378 ret = tun_set_ebpf(tun, &tun->steering_prog, argp);
3379 break;
3380
3381 case TUNSETFILTEREBPF:
3382 ret = tun_set_ebpf(tun, &tun->filter_prog, argp);
3383 break;
3384
3385 case TUNSETCARRIER:
3386 ret = -EFAULT;
3387 if (copy_from_user(&carrier, argp, sizeof(carrier)))
3388 goto unlock;
3389
3390 ret = tun_net_change_carrier(tun->dev, (bool)carrier);
3391 break;
3392
3393 case TUNGETDEVNETNS:
3394 ret = -EPERM;
3395 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
3396 goto unlock;
3397 ret = open_related_ns(&net->ns, get_net_ns);
3398 break;
3399
3400 default:
3401 ret = -EINVAL;
3402 break;
3403 }
3404
3405 if (do_notify)
3406 netdev_state_change(tun->dev);
3407
3408unlock:
3409 rtnl_unlock();
3410 if (tun)
3411 tun_put(tun);
3412 return ret;
3413}
3414
3415static long tun_chr_ioctl(struct file *file,
3416 unsigned int cmd, unsigned long arg)
3417{
3418 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
3419}
3420
3421#ifdef CONFIG_COMPAT
3422static long tun_chr_compat_ioctl(struct file *file,
3423 unsigned int cmd, unsigned long arg)
3424{
3425 switch (cmd) {
3426 case TUNSETIFF:
3427 case TUNGETIFF:
3428 case TUNSETTXFILTER:
3429 case TUNGETSNDBUF:
3430 case TUNSETSNDBUF:
3431 case SIOCGIFHWADDR:
3432 case SIOCSIFHWADDR:
3433 arg = (unsigned long)compat_ptr(arg);
3434 break;
3435 default:
3436 arg = (compat_ulong_t)arg;
3437 break;
3438 }
3439
3440 /*
3441 * compat_ifreq is shorter than ifreq, so we must not access beyond
3442 * the end of that structure. All fields that are used in this
3443 * driver are compatible though, we don't need to convert the
3444 * contents.
3445 */
3446 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
3447}
3448#endif /* CONFIG_COMPAT */
3449
3450static int tun_chr_fasync(int fd, struct file *file, int on)
3451{
3452 struct tun_file *tfile = file->private_data;
3453 int ret;
3454
3455 if (on) {
3456 ret = file_f_owner_allocate(file);
3457 if (ret)
3458 goto out;
3459 }
3460
3461 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
3462 goto out;
3463
3464 if (on) {
3465 __f_setown(file, task_pid(current), PIDTYPE_TGID, 0);
3466 tfile->flags |= TUN_FASYNC;
3467 } else
3468 tfile->flags &= ~TUN_FASYNC;
3469 ret = 0;
3470out:
3471 return ret;
3472}
3473
3474static int tun_chr_open(struct inode *inode, struct file * file)
3475{
3476 struct net *net = current->nsproxy->net_ns;
3477 struct tun_file *tfile;
3478
3479 tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
3480 &tun_proto, 0);
3481 if (!tfile)
3482 return -ENOMEM;
3483 if (ptr_ring_init(&tfile->tx_ring, 0, GFP_KERNEL)) {
3484 sk_free(&tfile->sk);
3485 return -ENOMEM;
3486 }
3487
3488 mutex_init(&tfile->napi_mutex);
3489 RCU_INIT_POINTER(tfile->tun, NULL);
3490 tfile->flags = 0;
3491 tfile->ifindex = 0;
3492
3493 init_waitqueue_head(&tfile->socket.wq.wait);
3494
3495 tfile->socket.file = file;
3496 tfile->socket.ops = &tun_socket_ops;
3497
3498 sock_init_data_uid(&tfile->socket, &tfile->sk, current_fsuid());
3499
3500 tfile->sk.sk_write_space = tun_sock_write_space;
3501 tfile->sk.sk_sndbuf = INT_MAX;
3502
3503 file->private_data = tfile;
3504 INIT_LIST_HEAD(&tfile->next);
3505
3506 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
3507
3508 /* tun groks IOCB_NOWAIT just fine, mark it as such */
3509 file->f_mode |= FMODE_NOWAIT;
3510 return 0;
3511}
3512
3513static int tun_chr_close(struct inode *inode, struct file *file)
3514{
3515 struct tun_file *tfile = file->private_data;
3516
3517 tun_detach(tfile, true);
3518
3519 return 0;
3520}
3521
3522#ifdef CONFIG_PROC_FS
3523static void tun_chr_show_fdinfo(struct seq_file *m, struct file *file)
3524{
3525 struct tun_file *tfile = file->private_data;
3526 struct tun_struct *tun;
3527 struct ifreq ifr;
3528
3529 memset(&ifr, 0, sizeof(ifr));
3530
3531 rtnl_lock();
3532 tun = tun_get(tfile);
3533 if (tun)
3534 tun_get_iff(tun, &ifr);
3535 rtnl_unlock();
3536
3537 if (tun)
3538 tun_put(tun);
3539
3540 seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
3541}
3542#endif
3543
3544static const struct file_operations tun_fops = {
3545 .owner = THIS_MODULE,
3546 .read_iter = tun_chr_read_iter,
3547 .write_iter = tun_chr_write_iter,
3548 .poll = tun_chr_poll,
3549 .unlocked_ioctl = tun_chr_ioctl,
3550#ifdef CONFIG_COMPAT
3551 .compat_ioctl = tun_chr_compat_ioctl,
3552#endif
3553 .open = tun_chr_open,
3554 .release = tun_chr_close,
3555 .fasync = tun_chr_fasync,
3556#ifdef CONFIG_PROC_FS
3557 .show_fdinfo = tun_chr_show_fdinfo,
3558#endif
3559};
3560
3561static struct miscdevice tun_miscdev = {
3562 .minor = TUN_MINOR,
3563 .name = "tun",
3564 .nodename = "net/tun",
3565 .fops = &tun_fops,
3566};
3567
3568/* ethtool interface */
3569
3570static void tun_default_link_ksettings(struct net_device *dev,
3571 struct ethtool_link_ksettings *cmd)
3572{
3573 ethtool_link_ksettings_zero_link_mode(cmd, supported);
3574 ethtool_link_ksettings_zero_link_mode(cmd, advertising);
3575 cmd->base.speed = SPEED_10000;
3576 cmd->base.duplex = DUPLEX_FULL;
3577 cmd->base.port = PORT_TP;
3578 cmd->base.phy_address = 0;
3579 cmd->base.autoneg = AUTONEG_DISABLE;
3580}
3581
3582static int tun_get_link_ksettings(struct net_device *dev,
3583 struct ethtool_link_ksettings *cmd)
3584{
3585 struct tun_struct *tun = netdev_priv(dev);
3586
3587 memcpy(cmd, &tun->link_ksettings, sizeof(*cmd));
3588 return 0;
3589}
3590
3591static int tun_set_link_ksettings(struct net_device *dev,
3592 const struct ethtool_link_ksettings *cmd)
3593{
3594 struct tun_struct *tun = netdev_priv(dev);
3595
3596 memcpy(&tun->link_ksettings, cmd, sizeof(*cmd));
3597 return 0;
3598}
3599
3600static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
3601{
3602 struct tun_struct *tun = netdev_priv(dev);
3603
3604 strscpy(info->driver, DRV_NAME, sizeof(info->driver));
3605 strscpy(info->version, DRV_VERSION, sizeof(info->version));
3606
3607 switch (tun->flags & TUN_TYPE_MASK) {
3608 case IFF_TUN:
3609 strscpy(info->bus_info, "tun", sizeof(info->bus_info));
3610 break;
3611 case IFF_TAP:
3612 strscpy(info->bus_info, "tap", sizeof(info->bus_info));
3613 break;
3614 }
3615}
3616
3617static u32 tun_get_msglevel(struct net_device *dev)
3618{
3619 struct tun_struct *tun = netdev_priv(dev);
3620
3621 return tun->msg_enable;
3622}
3623
3624static void tun_set_msglevel(struct net_device *dev, u32 value)
3625{
3626 struct tun_struct *tun = netdev_priv(dev);
3627
3628 tun->msg_enable = value;
3629}
3630
3631static int tun_get_coalesce(struct net_device *dev,
3632 struct ethtool_coalesce *ec,
3633 struct kernel_ethtool_coalesce *kernel_coal,
3634 struct netlink_ext_ack *extack)
3635{
3636 struct tun_struct *tun = netdev_priv(dev);
3637
3638 ec->rx_max_coalesced_frames = tun->rx_batched;
3639
3640 return 0;
3641}
3642
3643static int tun_set_coalesce(struct net_device *dev,
3644 struct ethtool_coalesce *ec,
3645 struct kernel_ethtool_coalesce *kernel_coal,
3646 struct netlink_ext_ack *extack)
3647{
3648 struct tun_struct *tun = netdev_priv(dev);
3649
3650 if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT)
3651 tun->rx_batched = NAPI_POLL_WEIGHT;
3652 else
3653 tun->rx_batched = ec->rx_max_coalesced_frames;
3654
3655 return 0;
3656}
3657
3658static void tun_get_channels(struct net_device *dev,
3659 struct ethtool_channels *channels)
3660{
3661 struct tun_struct *tun = netdev_priv(dev);
3662
3663 channels->combined_count = tun->numqueues;
3664 channels->max_combined = tun->flags & IFF_MULTI_QUEUE ? MAX_TAP_QUEUES : 1;
3665}
3666
3667static const struct ethtool_ops tun_ethtool_ops = {
3668 .supported_coalesce_params = ETHTOOL_COALESCE_RX_MAX_FRAMES,
3669 .get_drvinfo = tun_get_drvinfo,
3670 .get_msglevel = tun_get_msglevel,
3671 .set_msglevel = tun_set_msglevel,
3672 .get_link = ethtool_op_get_link,
3673 .get_channels = tun_get_channels,
3674 .get_ts_info = ethtool_op_get_ts_info,
3675 .get_coalesce = tun_get_coalesce,
3676 .set_coalesce = tun_set_coalesce,
3677 .get_link_ksettings = tun_get_link_ksettings,
3678 .set_link_ksettings = tun_set_link_ksettings,
3679};
3680
3681static int tun_queue_resize(struct tun_struct *tun)
3682{
3683 struct net_device *dev = tun->dev;
3684 struct tun_file *tfile;
3685 struct ptr_ring **rings;
3686 int n = tun->numqueues + tun->numdisabled;
3687 int ret, i;
3688
3689 rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL);
3690 if (!rings)
3691 return -ENOMEM;
3692
3693 for (i = 0; i < tun->numqueues; i++) {
3694 tfile = rtnl_dereference(tun->tfiles[i]);
3695 rings[i] = &tfile->tx_ring;
3696 }
3697 list_for_each_entry(tfile, &tun->disabled, next)
3698 rings[i++] = &tfile->tx_ring;
3699
3700 ret = ptr_ring_resize_multiple_bh(rings, n,
3701 dev->tx_queue_len, GFP_KERNEL,
3702 tun_ptr_free);
3703
3704 kfree(rings);
3705 return ret;
3706}
3707
3708static int tun_device_event(struct notifier_block *unused,
3709 unsigned long event, void *ptr)
3710{
3711 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3712 struct tun_struct *tun = netdev_priv(dev);
3713 int i;
3714
3715 if (dev->rtnl_link_ops != &tun_link_ops)
3716 return NOTIFY_DONE;
3717
3718 switch (event) {
3719 case NETDEV_CHANGE_TX_QUEUE_LEN:
3720 if (tun_queue_resize(tun))
3721 return NOTIFY_BAD;
3722 break;
3723 case NETDEV_UP:
3724 for (i = 0; i < tun->numqueues; i++) {
3725 struct tun_file *tfile;
3726
3727 tfile = rtnl_dereference(tun->tfiles[i]);
3728 tfile->socket.sk->sk_write_space(tfile->socket.sk);
3729 }
3730 break;
3731 default:
3732 break;
3733 }
3734
3735 return NOTIFY_DONE;
3736}
3737
3738static struct notifier_block tun_notifier_block __read_mostly = {
3739 .notifier_call = tun_device_event,
3740};
3741
3742static int __init tun_init(void)
3743{
3744 int ret = 0;
3745
3746 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
3747
3748 ret = rtnl_link_register(&tun_link_ops);
3749 if (ret) {
3750 pr_err("Can't register link_ops\n");
3751 goto err_linkops;
3752 }
3753
3754 ret = misc_register(&tun_miscdev);
3755 if (ret) {
3756 pr_err("Can't register misc device %d\n", TUN_MINOR);
3757 goto err_misc;
3758 }
3759
3760 ret = register_netdevice_notifier(&tun_notifier_block);
3761 if (ret) {
3762 pr_err("Can't register netdevice notifier\n");
3763 goto err_notifier;
3764 }
3765
3766 return 0;
3767
3768err_notifier:
3769 misc_deregister(&tun_miscdev);
3770err_misc:
3771 rtnl_link_unregister(&tun_link_ops);
3772err_linkops:
3773 return ret;
3774}
3775
3776static void __exit tun_cleanup(void)
3777{
3778 misc_deregister(&tun_miscdev);
3779 rtnl_link_unregister(&tun_link_ops);
3780 unregister_netdevice_notifier(&tun_notifier_block);
3781}
3782
3783/* Get an underlying socket object from tun file. Returns error unless file is
3784 * attached to a device. The returned object works like a packet socket, it
3785 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
3786 * holding a reference to the file for as long as the socket is in use. */
3787struct socket *tun_get_socket(struct file *file)
3788{
3789 struct tun_file *tfile;
3790 if (file->f_op != &tun_fops)
3791 return ERR_PTR(-EINVAL);
3792 tfile = file->private_data;
3793 if (!tfile)
3794 return ERR_PTR(-EBADFD);
3795 return &tfile->socket;
3796}
3797EXPORT_SYMBOL_GPL(tun_get_socket);
3798
3799struct ptr_ring *tun_get_tx_ring(struct file *file)
3800{
3801 struct tun_file *tfile;
3802
3803 if (file->f_op != &tun_fops)
3804 return ERR_PTR(-EINVAL);
3805 tfile = file->private_data;
3806 if (!tfile)
3807 return ERR_PTR(-EBADFD);
3808 return &tfile->tx_ring;
3809}
3810EXPORT_SYMBOL_GPL(tun_get_tx_ring);
3811
3812module_init(tun_init);
3813module_exit(tun_cleanup);
3814MODULE_DESCRIPTION(DRV_DESCRIPTION);
3815MODULE_AUTHOR(DRV_COPYRIGHT);
3816MODULE_LICENSE("GPL");
3817MODULE_ALIAS_MISCDEV(TUN_MINOR);
3818MODULE_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
75#include <asm/uaccess.h>
76
77/* Uncomment to enable debugging */
78/* #define TUN_DEBUG 1 */
79
80#ifdef TUN_DEBUG
81static int debug;
82
83#define tun_debug(level, tun, fmt, args...) \
84do { \
85 if (tun->debug) \
86 netdev_printk(level, tun->dev, fmt, ##args); \
87} while (0)
88#define DBG1(level, fmt, args...) \
89do { \
90 if (debug == 2) \
91 printk(level fmt, ##args); \
92} while (0)
93#else
94#define tun_debug(level, tun, fmt, args...) \
95do { \
96 if (0) \
97 netdev_printk(level, tun->dev, fmt, ##args); \
98} while (0)
99#define DBG1(level, fmt, args...) \
100do { \
101 if (0) \
102 printk(level fmt, ##args); \
103} while (0)
104#endif
105
106/* TUN device flags */
107
108/* IFF_ATTACH_QUEUE is never stored in device flags,
109 * overload it to mean fasync when stored there.
110 */
111#define TUN_FASYNC IFF_ATTACH_QUEUE
112/* High bits in flags field are unused. */
113#define TUN_VNET_LE 0x80000000
114#define TUN_VNET_BE 0x40000000
115
116#define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
117 IFF_MULTI_QUEUE)
118#define GOODCOPY_LEN 128
119
120#define FLT_EXACT_COUNT 8
121struct tap_filter {
122 unsigned int count; /* Number of addrs. Zero means disabled */
123 u32 mask[2]; /* Mask of the hashed addrs */
124 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
125};
126
127/* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
128 * to max number of VCPUs in guest. */
129#define MAX_TAP_QUEUES 256
130#define MAX_TAP_FLOWS 4096
131
132#define TUN_FLOW_EXPIRE (3 * HZ)
133
134/* A tun_file connects an open character device to a tuntap netdevice. It
135 * also contains all socket related structures (except sock_fprog and tap_filter)
136 * to serve as one transmit queue for tuntap device. The sock_fprog and
137 * tap_filter were kept in tun_struct since they were used for filtering for the
138 * netdevice not for a specific queue (at least I didn't see the requirement for
139 * this).
140 *
141 * RCU usage:
142 * The tun_file and tun_struct are loosely coupled, the pointer from one to the
143 * other can only be read while rcu_read_lock or rtnl_lock is held.
144 */
145struct tun_file {
146 struct sock sk;
147 struct socket socket;
148 struct socket_wq wq;
149 struct tun_struct __rcu *tun;
150 struct fasync_struct *fasync;
151 /* only used for fasnyc */
152 unsigned int flags;
153 union {
154 u16 queue_index;
155 unsigned int ifindex;
156 };
157 struct list_head next;
158 struct tun_struct *detached;
159};
160
161struct tun_flow_entry {
162 struct hlist_node hash_link;
163 struct rcu_head rcu;
164 struct tun_struct *tun;
165
166 u32 rxhash;
167 u32 rps_rxhash;
168 int queue_index;
169 unsigned long updated;
170};
171
172#define TUN_NUM_FLOW_ENTRIES 1024
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_UFO)
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#ifdef TUN_DEBUG
198 int debug;
199#endif
200 spinlock_t lock;
201 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
202 struct timer_list flow_gc_timer;
203 unsigned long ageing_time;
204 unsigned int numdisabled;
205 struct list_head disabled;
206 void *security;
207 u32 flow_count;
208};
209
210#ifdef CONFIG_TUN_VNET_CROSS_LE
211static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
212{
213 return tun->flags & TUN_VNET_BE ? false :
214 virtio_legacy_is_little_endian();
215}
216
217static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
218{
219 int be = !!(tun->flags & TUN_VNET_BE);
220
221 if (put_user(be, argp))
222 return -EFAULT;
223
224 return 0;
225}
226
227static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
228{
229 int be;
230
231 if (get_user(be, argp))
232 return -EFAULT;
233
234 if (be)
235 tun->flags |= TUN_VNET_BE;
236 else
237 tun->flags &= ~TUN_VNET_BE;
238
239 return 0;
240}
241#else
242static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
243{
244 return virtio_legacy_is_little_endian();
245}
246
247static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
248{
249 return -EINVAL;
250}
251
252static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
253{
254 return -EINVAL;
255}
256#endif /* CONFIG_TUN_VNET_CROSS_LE */
257
258static inline bool tun_is_little_endian(struct tun_struct *tun)
259{
260 return tun->flags & TUN_VNET_LE ||
261 tun_legacy_is_little_endian(tun);
262}
263
264static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
265{
266 return __virtio16_to_cpu(tun_is_little_endian(tun), val);
267}
268
269static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
270{
271 return __cpu_to_virtio16(tun_is_little_endian(tun), val);
272}
273
274static inline u32 tun_hashfn(u32 rxhash)
275{
276 return rxhash & 0x3ff;
277}
278
279static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
280{
281 struct tun_flow_entry *e;
282
283 hlist_for_each_entry_rcu(e, head, hash_link) {
284 if (e->rxhash == rxhash)
285 return e;
286 }
287 return NULL;
288}
289
290static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
291 struct hlist_head *head,
292 u32 rxhash, u16 queue_index)
293{
294 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
295
296 if (e) {
297 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
298 rxhash, queue_index);
299 e->updated = jiffies;
300 e->rxhash = rxhash;
301 e->rps_rxhash = 0;
302 e->queue_index = queue_index;
303 e->tun = tun;
304 hlist_add_head_rcu(&e->hash_link, head);
305 ++tun->flow_count;
306 }
307 return e;
308}
309
310static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
311{
312 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
313 e->rxhash, e->queue_index);
314 hlist_del_rcu(&e->hash_link);
315 kfree_rcu(e, rcu);
316 --tun->flow_count;
317}
318
319static void tun_flow_flush(struct tun_struct *tun)
320{
321 int i;
322
323 spin_lock_bh(&tun->lock);
324 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
325 struct tun_flow_entry *e;
326 struct hlist_node *n;
327
328 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
329 tun_flow_delete(tun, e);
330 }
331 spin_unlock_bh(&tun->lock);
332}
333
334static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
335{
336 int i;
337
338 spin_lock_bh(&tun->lock);
339 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
340 struct tun_flow_entry *e;
341 struct hlist_node *n;
342
343 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
344 if (e->queue_index == queue_index)
345 tun_flow_delete(tun, e);
346 }
347 }
348 spin_unlock_bh(&tun->lock);
349}
350
351static void tun_flow_cleanup(unsigned long data)
352{
353 struct tun_struct *tun = (struct tun_struct *)data;
354 unsigned long delay = tun->ageing_time;
355 unsigned long next_timer = jiffies + delay;
356 unsigned long count = 0;
357 int i;
358
359 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
360
361 spin_lock_bh(&tun->lock);
362 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
363 struct tun_flow_entry *e;
364 struct hlist_node *n;
365
366 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
367 unsigned long this_timer;
368 count++;
369 this_timer = e->updated + delay;
370 if (time_before_eq(this_timer, jiffies))
371 tun_flow_delete(tun, e);
372 else if (time_before(this_timer, next_timer))
373 next_timer = this_timer;
374 }
375 }
376
377 if (count)
378 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
379 spin_unlock_bh(&tun->lock);
380}
381
382static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
383 struct tun_file *tfile)
384{
385 struct hlist_head *head;
386 struct tun_flow_entry *e;
387 unsigned long delay = tun->ageing_time;
388 u16 queue_index = tfile->queue_index;
389
390 if (!rxhash)
391 return;
392 else
393 head = &tun->flows[tun_hashfn(rxhash)];
394
395 rcu_read_lock();
396
397 /* We may get a very small possibility of OOO during switching, not
398 * worth to optimize.*/
399 if (tun->numqueues == 1 || tfile->detached)
400 goto unlock;
401
402 e = tun_flow_find(head, rxhash);
403 if (likely(e)) {
404 /* TODO: keep queueing to old queue until it's empty? */
405 e->queue_index = queue_index;
406 e->updated = jiffies;
407 sock_rps_record_flow_hash(e->rps_rxhash);
408 } else {
409 spin_lock_bh(&tun->lock);
410 if (!tun_flow_find(head, rxhash) &&
411 tun->flow_count < MAX_TAP_FLOWS)
412 tun_flow_create(tun, head, rxhash, queue_index);
413
414 if (!timer_pending(&tun->flow_gc_timer))
415 mod_timer(&tun->flow_gc_timer,
416 round_jiffies_up(jiffies + delay));
417 spin_unlock_bh(&tun->lock);
418 }
419
420unlock:
421 rcu_read_unlock();
422}
423
424/**
425 * Save the hash received in the stack receive path and update the
426 * flow_hash table accordingly.
427 */
428static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
429{
430 if (unlikely(e->rps_rxhash != hash))
431 e->rps_rxhash = hash;
432}
433
434/* We try to identify a flow through its rxhash first. The reason that
435 * we do not check rxq no. is because some cards(e.g 82599), chooses
436 * the rxq based on the txq where the last packet of the flow comes. As
437 * the userspace application move between processors, we may get a
438 * different rxq no. here. If we could not get rxhash, then we would
439 * hope the rxq no. may help here.
440 */
441static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
442 void *accel_priv, select_queue_fallback_t fallback)
443{
444 struct tun_struct *tun = netdev_priv(dev);
445 struct tun_flow_entry *e;
446 u32 txq = 0;
447 u32 numqueues = 0;
448
449 rcu_read_lock();
450 numqueues = ACCESS_ONCE(tun->numqueues);
451
452 txq = skb_get_hash(skb);
453 if (txq) {
454 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
455 if (e) {
456 tun_flow_save_rps_rxhash(e, txq);
457 txq = e->queue_index;
458 } else
459 /* use multiply and shift instead of expensive divide */
460 txq = ((u64)txq * numqueues) >> 32;
461 } else if (likely(skb_rx_queue_recorded(skb))) {
462 txq = skb_get_rx_queue(skb);
463 while (unlikely(txq >= numqueues))
464 txq -= numqueues;
465 }
466
467 rcu_read_unlock();
468 return txq;
469}
470
471static inline bool tun_not_capable(struct tun_struct *tun)
472{
473 const struct cred *cred = current_cred();
474 struct net *net = dev_net(tun->dev);
475
476 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
477 (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
478 !ns_capable(net->user_ns, CAP_NET_ADMIN);
479}
480
481static void tun_set_real_num_queues(struct tun_struct *tun)
482{
483 netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
484 netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
485}
486
487static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
488{
489 tfile->detached = tun;
490 list_add_tail(&tfile->next, &tun->disabled);
491 ++tun->numdisabled;
492}
493
494static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
495{
496 struct tun_struct *tun = tfile->detached;
497
498 tfile->detached = NULL;
499 list_del_init(&tfile->next);
500 --tun->numdisabled;
501 return tun;
502}
503
504static void tun_queue_purge(struct tun_file *tfile)
505{
506 skb_queue_purge(&tfile->sk.sk_receive_queue);
507 skb_queue_purge(&tfile->sk.sk_error_queue);
508}
509
510static void __tun_detach(struct tun_file *tfile, bool clean)
511{
512 struct tun_file *ntfile;
513 struct tun_struct *tun;
514
515 tun = rtnl_dereference(tfile->tun);
516
517 if (tun && !tfile->detached) {
518 u16 index = tfile->queue_index;
519 BUG_ON(index >= tun->numqueues);
520
521 rcu_assign_pointer(tun->tfiles[index],
522 tun->tfiles[tun->numqueues - 1]);
523 ntfile = rtnl_dereference(tun->tfiles[index]);
524 ntfile->queue_index = index;
525
526 --tun->numqueues;
527 if (clean) {
528 RCU_INIT_POINTER(tfile->tun, NULL);
529 sock_put(&tfile->sk);
530 } else
531 tun_disable_queue(tun, tfile);
532
533 synchronize_net();
534 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
535 /* Drop read queue */
536 tun_queue_purge(tfile);
537 tun_set_real_num_queues(tun);
538 } else if (tfile->detached && clean) {
539 tun = tun_enable_queue(tfile);
540 sock_put(&tfile->sk);
541 }
542
543 if (clean) {
544 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
545 netif_carrier_off(tun->dev);
546
547 if (!(tun->flags & IFF_PERSIST) &&
548 tun->dev->reg_state == NETREG_REGISTERED)
549 unregister_netdevice(tun->dev);
550 }
551 sock_put(&tfile->sk);
552 }
553}
554
555static void tun_detach(struct tun_file *tfile, bool clean)
556{
557 rtnl_lock();
558 __tun_detach(tfile, clean);
559 rtnl_unlock();
560}
561
562static void tun_detach_all(struct net_device *dev)
563{
564 struct tun_struct *tun = netdev_priv(dev);
565 struct tun_file *tfile, *tmp;
566 int i, n = tun->numqueues;
567
568 for (i = 0; i < n; i++) {
569 tfile = rtnl_dereference(tun->tfiles[i]);
570 BUG_ON(!tfile);
571 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
572 RCU_INIT_POINTER(tfile->tun, NULL);
573 --tun->numqueues;
574 }
575 list_for_each_entry(tfile, &tun->disabled, next) {
576 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
577 RCU_INIT_POINTER(tfile->tun, NULL);
578 }
579 BUG_ON(tun->numqueues != 0);
580
581 synchronize_net();
582 for (i = 0; i < n; i++) {
583 tfile = rtnl_dereference(tun->tfiles[i]);
584 /* Drop read queue */
585 tun_queue_purge(tfile);
586 sock_put(&tfile->sk);
587 }
588 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
589 tun_enable_queue(tfile);
590 tun_queue_purge(tfile);
591 sock_put(&tfile->sk);
592 }
593 BUG_ON(tun->numdisabled != 0);
594
595 if (tun->flags & IFF_PERSIST)
596 module_put(THIS_MODULE);
597}
598
599static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter)
600{
601 struct tun_file *tfile = file->private_data;
602 int err;
603
604 err = security_tun_dev_attach(tfile->socket.sk, tun->security);
605 if (err < 0)
606 goto out;
607
608 err = -EINVAL;
609 if (rtnl_dereference(tfile->tun) && !tfile->detached)
610 goto out;
611
612 err = -EBUSY;
613 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
614 goto out;
615
616 err = -E2BIG;
617 if (!tfile->detached &&
618 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
619 goto out;
620
621 err = 0;
622
623 /* Re-attach the filter to persist device */
624 if (!skip_filter && (tun->filter_attached == true)) {
625 err = __sk_attach_filter(&tun->fprog, tfile->socket.sk,
626 lockdep_rtnl_is_held());
627 if (!err)
628 goto out;
629 }
630 tfile->queue_index = tun->numqueues;
631 rcu_assign_pointer(tfile->tun, tun);
632 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
633 tun->numqueues++;
634
635 if (tfile->detached)
636 tun_enable_queue(tfile);
637 else
638 sock_hold(&tfile->sk);
639
640 tun_set_real_num_queues(tun);
641
642 /* device is allowed to go away first, so no need to hold extra
643 * refcnt.
644 */
645
646out:
647 return err;
648}
649
650static struct tun_struct *__tun_get(struct tun_file *tfile)
651{
652 struct tun_struct *tun;
653
654 rcu_read_lock();
655 tun = rcu_dereference(tfile->tun);
656 if (tun)
657 dev_hold(tun->dev);
658 rcu_read_unlock();
659
660 return tun;
661}
662
663static struct tun_struct *tun_get(struct file *file)
664{
665 return __tun_get(file->private_data);
666}
667
668static void tun_put(struct tun_struct *tun)
669{
670 dev_put(tun->dev);
671}
672
673/* TAP filtering */
674static void addr_hash_set(u32 *mask, const u8 *addr)
675{
676 int n = ether_crc(ETH_ALEN, addr) >> 26;
677 mask[n >> 5] |= (1 << (n & 31));
678}
679
680static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
681{
682 int n = ether_crc(ETH_ALEN, addr) >> 26;
683 return mask[n >> 5] & (1 << (n & 31));
684}
685
686static int update_filter(struct tap_filter *filter, void __user *arg)
687{
688 struct { u8 u[ETH_ALEN]; } *addr;
689 struct tun_filter uf;
690 int err, alen, n, nexact;
691
692 if (copy_from_user(&uf, arg, sizeof(uf)))
693 return -EFAULT;
694
695 if (!uf.count) {
696 /* Disabled */
697 filter->count = 0;
698 return 0;
699 }
700
701 alen = ETH_ALEN * uf.count;
702 addr = kmalloc(alen, GFP_KERNEL);
703 if (!addr)
704 return -ENOMEM;
705
706 if (copy_from_user(addr, arg + sizeof(uf), alen)) {
707 err = -EFAULT;
708 goto done;
709 }
710
711 /* The filter is updated without holding any locks. Which is
712 * perfectly safe. We disable it first and in the worst
713 * case we'll accept a few undesired packets. */
714 filter->count = 0;
715 wmb();
716
717 /* Use first set of addresses as an exact filter */
718 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
719 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
720
721 nexact = n;
722
723 /* Remaining multicast addresses are hashed,
724 * unicast will leave the filter disabled. */
725 memset(filter->mask, 0, sizeof(filter->mask));
726 for (; n < uf.count; n++) {
727 if (!is_multicast_ether_addr(addr[n].u)) {
728 err = 0; /* no filter */
729 goto done;
730 }
731 addr_hash_set(filter->mask, addr[n].u);
732 }
733
734 /* For ALLMULTI just set the mask to all ones.
735 * This overrides the mask populated above. */
736 if ((uf.flags & TUN_FLT_ALLMULTI))
737 memset(filter->mask, ~0, sizeof(filter->mask));
738
739 /* Now enable the filter */
740 wmb();
741 filter->count = nexact;
742
743 /* Return the number of exact filters */
744 err = nexact;
745
746done:
747 kfree(addr);
748 return err;
749}
750
751/* Returns: 0 - drop, !=0 - accept */
752static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
753{
754 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
755 * at this point. */
756 struct ethhdr *eh = (struct ethhdr *) skb->data;
757 int i;
758
759 /* Exact match */
760 for (i = 0; i < filter->count; i++)
761 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
762 return 1;
763
764 /* Inexact match (multicast only) */
765 if (is_multicast_ether_addr(eh->h_dest))
766 return addr_hash_test(filter->mask, eh->h_dest);
767
768 return 0;
769}
770
771/*
772 * Checks whether the packet is accepted or not.
773 * Returns: 0 - drop, !=0 - accept
774 */
775static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
776{
777 if (!filter->count)
778 return 1;
779
780 return run_filter(filter, skb);
781}
782
783/* Network device part of the driver */
784
785static const struct ethtool_ops tun_ethtool_ops;
786
787/* Net device detach from fd. */
788static void tun_net_uninit(struct net_device *dev)
789{
790 tun_detach_all(dev);
791}
792
793/* Net device open. */
794static int tun_net_open(struct net_device *dev)
795{
796 netif_tx_start_all_queues(dev);
797 return 0;
798}
799
800/* Net device close. */
801static int tun_net_close(struct net_device *dev)
802{
803 netif_tx_stop_all_queues(dev);
804 return 0;
805}
806
807/* Net device start xmit */
808static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
809{
810 struct tun_struct *tun = netdev_priv(dev);
811 int txq = skb->queue_mapping;
812 struct tun_file *tfile;
813 u32 numqueues = 0;
814
815 rcu_read_lock();
816 tfile = rcu_dereference(tun->tfiles[txq]);
817 numqueues = ACCESS_ONCE(tun->numqueues);
818
819 /* Drop packet if interface is not attached */
820 if (txq >= numqueues)
821 goto drop;
822
823 if (numqueues == 1) {
824 /* Select queue was not called for the skbuff, so we extract the
825 * RPS hash and save it into the flow_table here.
826 */
827 __u32 rxhash;
828
829 rxhash = skb_get_hash(skb);
830 if (rxhash) {
831 struct tun_flow_entry *e;
832 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)],
833 rxhash);
834 if (e)
835 tun_flow_save_rps_rxhash(e, rxhash);
836 }
837 }
838
839 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
840
841 BUG_ON(!tfile);
842
843 /* Drop if the filter does not like it.
844 * This is a noop if the filter is disabled.
845 * Filter can be enabled only for the TAP devices. */
846 if (!check_filter(&tun->txflt, skb))
847 goto drop;
848
849 if (tfile->socket.sk->sk_filter &&
850 sk_filter(tfile->socket.sk, skb))
851 goto drop;
852
853 /* Limit the number of packets queued by dividing txq length with the
854 * number of queues.
855 */
856 if (skb_queue_len(&tfile->socket.sk->sk_receive_queue) * numqueues
857 >= dev->tx_queue_len)
858 goto drop;
859
860 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
861 goto drop;
862
863 if (skb->sk && sk_fullsock(skb->sk)) {
864 sock_tx_timestamp(skb->sk, &skb_shinfo(skb)->tx_flags);
865 sw_tx_timestamp(skb);
866 }
867
868 /* Orphan the skb - required as we might hang on to it
869 * for indefinite time.
870 */
871 skb_orphan(skb);
872
873 nf_reset(skb);
874
875 /* Enqueue packet */
876 skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb);
877
878 /* Notify and wake up reader process */
879 if (tfile->flags & TUN_FASYNC)
880 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
881 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
882
883 rcu_read_unlock();
884 return NETDEV_TX_OK;
885
886drop:
887 dev->stats.tx_dropped++;
888 skb_tx_error(skb);
889 kfree_skb(skb);
890 rcu_read_unlock();
891 return NET_XMIT_DROP;
892}
893
894static void tun_net_mclist(struct net_device *dev)
895{
896 /*
897 * This callback is supposed to deal with mc filter in
898 * _rx_ path and has nothing to do with the _tx_ path.
899 * In rx path we always accept everything userspace gives us.
900 */
901}
902
903#define MIN_MTU 68
904#define MAX_MTU 65535
905
906static int
907tun_net_change_mtu(struct net_device *dev, int new_mtu)
908{
909 if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
910 return -EINVAL;
911 dev->mtu = new_mtu;
912 return 0;
913}
914
915static netdev_features_t tun_net_fix_features(struct net_device *dev,
916 netdev_features_t features)
917{
918 struct tun_struct *tun = netdev_priv(dev);
919
920 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
921}
922#ifdef CONFIG_NET_POLL_CONTROLLER
923static void tun_poll_controller(struct net_device *dev)
924{
925 /*
926 * Tun only receives frames when:
927 * 1) the char device endpoint gets data from user space
928 * 2) the tun socket gets a sendmsg call from user space
929 * Since both of those are synchronous operations, we are guaranteed
930 * never to have pending data when we poll for it
931 * so there is nothing to do here but return.
932 * We need this though so netpoll recognizes us as an interface that
933 * supports polling, which enables bridge devices in virt setups to
934 * still use netconsole
935 */
936 return;
937}
938#endif
939
940static void tun_set_headroom(struct net_device *dev, int new_hr)
941{
942 struct tun_struct *tun = netdev_priv(dev);
943
944 if (new_hr < NET_SKB_PAD)
945 new_hr = NET_SKB_PAD;
946
947 tun->align = new_hr;
948}
949
950static const struct net_device_ops tun_netdev_ops = {
951 .ndo_uninit = tun_net_uninit,
952 .ndo_open = tun_net_open,
953 .ndo_stop = tun_net_close,
954 .ndo_start_xmit = tun_net_xmit,
955 .ndo_change_mtu = tun_net_change_mtu,
956 .ndo_fix_features = tun_net_fix_features,
957 .ndo_select_queue = tun_select_queue,
958#ifdef CONFIG_NET_POLL_CONTROLLER
959 .ndo_poll_controller = tun_poll_controller,
960#endif
961 .ndo_set_rx_headroom = tun_set_headroom,
962};
963
964static const struct net_device_ops tap_netdev_ops = {
965 .ndo_uninit = tun_net_uninit,
966 .ndo_open = tun_net_open,
967 .ndo_stop = tun_net_close,
968 .ndo_start_xmit = tun_net_xmit,
969 .ndo_change_mtu = tun_net_change_mtu,
970 .ndo_fix_features = tun_net_fix_features,
971 .ndo_set_rx_mode = tun_net_mclist,
972 .ndo_set_mac_address = eth_mac_addr,
973 .ndo_validate_addr = eth_validate_addr,
974 .ndo_select_queue = tun_select_queue,
975#ifdef CONFIG_NET_POLL_CONTROLLER
976 .ndo_poll_controller = tun_poll_controller,
977#endif
978 .ndo_features_check = passthru_features_check,
979 .ndo_set_rx_headroom = tun_set_headroom,
980};
981
982static void tun_flow_init(struct tun_struct *tun)
983{
984 int i;
985
986 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
987 INIT_HLIST_HEAD(&tun->flows[i]);
988
989 tun->ageing_time = TUN_FLOW_EXPIRE;
990 setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun);
991 mod_timer(&tun->flow_gc_timer,
992 round_jiffies_up(jiffies + tun->ageing_time));
993}
994
995static void tun_flow_uninit(struct tun_struct *tun)
996{
997 del_timer_sync(&tun->flow_gc_timer);
998 tun_flow_flush(tun);
999}
1000
1001/* Initialize net device. */
1002static void tun_net_init(struct net_device *dev)
1003{
1004 struct tun_struct *tun = netdev_priv(dev);
1005
1006 switch (tun->flags & TUN_TYPE_MASK) {
1007 case IFF_TUN:
1008 dev->netdev_ops = &tun_netdev_ops;
1009
1010 /* Point-to-Point TUN Device */
1011 dev->hard_header_len = 0;
1012 dev->addr_len = 0;
1013 dev->mtu = 1500;
1014
1015 /* Zero header length */
1016 dev->type = ARPHRD_NONE;
1017 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1018 break;
1019
1020 case IFF_TAP:
1021 dev->netdev_ops = &tap_netdev_ops;
1022 /* Ethernet TAP Device */
1023 ether_setup(dev);
1024 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1025 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1026
1027 eth_hw_addr_random(dev);
1028
1029 break;
1030 }
1031}
1032
1033/* Character device part */
1034
1035/* Poll */
1036static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
1037{
1038 struct tun_file *tfile = file->private_data;
1039 struct tun_struct *tun = __tun_get(tfile);
1040 struct sock *sk;
1041 unsigned int mask = 0;
1042
1043 if (!tun)
1044 return POLLERR;
1045
1046 sk = tfile->socket.sk;
1047
1048 tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
1049
1050 poll_wait(file, sk_sleep(sk), wait);
1051
1052 if (!skb_queue_empty(&sk->sk_receive_queue))
1053 mask |= POLLIN | POLLRDNORM;
1054
1055 if (sock_writeable(sk) ||
1056 (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1057 sock_writeable(sk)))
1058 mask |= POLLOUT | POLLWRNORM;
1059
1060 if (tun->dev->reg_state != NETREG_REGISTERED)
1061 mask = POLLERR;
1062
1063 tun_put(tun);
1064 return mask;
1065}
1066
1067/* prepad is the amount to reserve at front. len is length after that.
1068 * linear is a hint as to how much to copy (usually headers). */
1069static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1070 size_t prepad, size_t len,
1071 size_t linear, int noblock)
1072{
1073 struct sock *sk = tfile->socket.sk;
1074 struct sk_buff *skb;
1075 int err;
1076
1077 /* Under a page? Don't bother with paged skb. */
1078 if (prepad + len < PAGE_SIZE || !linear)
1079 linear = len;
1080
1081 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1082 &err, 0);
1083 if (!skb)
1084 return ERR_PTR(err);
1085
1086 skb_reserve(skb, prepad);
1087 skb_put(skb, linear);
1088 skb->data_len = len - linear;
1089 skb->len += len - linear;
1090
1091 return skb;
1092}
1093
1094/* Get packet from user space buffer */
1095static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1096 void *msg_control, struct iov_iter *from,
1097 int noblock)
1098{
1099 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1100 struct sk_buff *skb;
1101 size_t total_len = iov_iter_count(from);
1102 size_t len = total_len, align = tun->align, linear;
1103 struct virtio_net_hdr gso = { 0 };
1104 int good_linear;
1105 int copylen;
1106 bool zerocopy = false;
1107 int err;
1108 u32 rxhash;
1109 ssize_t n;
1110
1111 if (!(tun->dev->flags & IFF_UP))
1112 return -EIO;
1113
1114 if (!(tun->flags & IFF_NO_PI)) {
1115 if (len < sizeof(pi))
1116 return -EINVAL;
1117 len -= sizeof(pi);
1118
1119 n = copy_from_iter(&pi, sizeof(pi), from);
1120 if (n != sizeof(pi))
1121 return -EFAULT;
1122 }
1123
1124 if (tun->flags & IFF_VNET_HDR) {
1125 if (len < tun->vnet_hdr_sz)
1126 return -EINVAL;
1127 len -= tun->vnet_hdr_sz;
1128
1129 n = copy_from_iter(&gso, sizeof(gso), from);
1130 if (n != sizeof(gso))
1131 return -EFAULT;
1132
1133 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1134 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1135 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1136
1137 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1138 return -EINVAL;
1139 iov_iter_advance(from, tun->vnet_hdr_sz - sizeof(gso));
1140 }
1141
1142 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1143 align += NET_IP_ALIGN;
1144 if (unlikely(len < ETH_HLEN ||
1145 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1146 return -EINVAL;
1147 }
1148
1149 good_linear = SKB_MAX_HEAD(align);
1150
1151 if (msg_control) {
1152 struct iov_iter i = *from;
1153
1154 /* There are 256 bytes to be copied in skb, so there is
1155 * enough room for skb expand head in case it is used.
1156 * The rest of the buffer is mapped from userspace.
1157 */
1158 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1159 if (copylen > good_linear)
1160 copylen = good_linear;
1161 linear = copylen;
1162 iov_iter_advance(&i, copylen);
1163 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1164 zerocopy = true;
1165 }
1166
1167 if (!zerocopy) {
1168 copylen = len;
1169 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1170 linear = good_linear;
1171 else
1172 linear = tun16_to_cpu(tun, gso.hdr_len);
1173 }
1174
1175 skb = tun_alloc_skb(tfile, align, copylen, linear, noblock);
1176 if (IS_ERR(skb)) {
1177 if (PTR_ERR(skb) != -EAGAIN)
1178 tun->dev->stats.rx_dropped++;
1179 return PTR_ERR(skb);
1180 }
1181
1182 if (zerocopy)
1183 err = zerocopy_sg_from_iter(skb, from);
1184 else {
1185 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1186 if (!err && msg_control) {
1187 struct ubuf_info *uarg = msg_control;
1188 uarg->callback(uarg, false);
1189 }
1190 }
1191
1192 if (err) {
1193 tun->dev->stats.rx_dropped++;
1194 kfree_skb(skb);
1195 return -EFAULT;
1196 }
1197
1198 if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
1199 if (!skb_partial_csum_set(skb, tun16_to_cpu(tun, gso.csum_start),
1200 tun16_to_cpu(tun, gso.csum_offset))) {
1201 tun->dev->stats.rx_frame_errors++;
1202 kfree_skb(skb);
1203 return -EINVAL;
1204 }
1205 }
1206
1207 switch (tun->flags & TUN_TYPE_MASK) {
1208 case IFF_TUN:
1209 if (tun->flags & IFF_NO_PI) {
1210 switch (skb->data[0] & 0xf0) {
1211 case 0x40:
1212 pi.proto = htons(ETH_P_IP);
1213 break;
1214 case 0x60:
1215 pi.proto = htons(ETH_P_IPV6);
1216 break;
1217 default:
1218 tun->dev->stats.rx_dropped++;
1219 kfree_skb(skb);
1220 return -EINVAL;
1221 }
1222 }
1223
1224 skb_reset_mac_header(skb);
1225 skb->protocol = pi.proto;
1226 skb->dev = tun->dev;
1227 break;
1228 case IFF_TAP:
1229 skb->protocol = eth_type_trans(skb, tun->dev);
1230 break;
1231 }
1232
1233 if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
1234 pr_debug("GSO!\n");
1235 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
1236 case VIRTIO_NET_HDR_GSO_TCPV4:
1237 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1238 break;
1239 case VIRTIO_NET_HDR_GSO_TCPV6:
1240 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
1241 break;
1242 case VIRTIO_NET_HDR_GSO_UDP:
1243 skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1244 break;
1245 default:
1246 tun->dev->stats.rx_frame_errors++;
1247 kfree_skb(skb);
1248 return -EINVAL;
1249 }
1250
1251 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
1252 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
1253
1254 skb_shinfo(skb)->gso_size = tun16_to_cpu(tun, gso.gso_size);
1255 if (skb_shinfo(skb)->gso_size == 0) {
1256 tun->dev->stats.rx_frame_errors++;
1257 kfree_skb(skb);
1258 return -EINVAL;
1259 }
1260
1261 /* Header must be checked, and gso_segs computed. */
1262 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
1263 skb_shinfo(skb)->gso_segs = 0;
1264 }
1265
1266 /* copy skb_ubuf_info for callback when skb has no error */
1267 if (zerocopy) {
1268 skb_shinfo(skb)->destructor_arg = msg_control;
1269 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1270 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1271 }
1272
1273 skb_reset_network_header(skb);
1274 skb_probe_transport_header(skb, 0);
1275
1276 rxhash = skb_get_hash(skb);
1277 netif_rx_ni(skb);
1278
1279 tun->dev->stats.rx_packets++;
1280 tun->dev->stats.rx_bytes += len;
1281
1282 tun_flow_update(tun, rxhash, tfile);
1283 return total_len;
1284}
1285
1286static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
1287{
1288 struct file *file = iocb->ki_filp;
1289 struct tun_struct *tun = tun_get(file);
1290 struct tun_file *tfile = file->private_data;
1291 ssize_t result;
1292
1293 if (!tun)
1294 return -EBADFD;
1295
1296 result = tun_get_user(tun, tfile, NULL, from, file->f_flags & O_NONBLOCK);
1297
1298 tun_put(tun);
1299 return result;
1300}
1301
1302/* Put packet to the user space buffer */
1303static ssize_t tun_put_user(struct tun_struct *tun,
1304 struct tun_file *tfile,
1305 struct sk_buff *skb,
1306 struct iov_iter *iter)
1307{
1308 struct tun_pi pi = { 0, skb->protocol };
1309 ssize_t total;
1310 int vlan_offset = 0;
1311 int vlan_hlen = 0;
1312 int vnet_hdr_sz = 0;
1313
1314 if (skb_vlan_tag_present(skb))
1315 vlan_hlen = VLAN_HLEN;
1316
1317 if (tun->flags & IFF_VNET_HDR)
1318 vnet_hdr_sz = tun->vnet_hdr_sz;
1319
1320 total = skb->len + vlan_hlen + vnet_hdr_sz;
1321
1322 if (!(tun->flags & IFF_NO_PI)) {
1323 if (iov_iter_count(iter) < sizeof(pi))
1324 return -EINVAL;
1325
1326 total += sizeof(pi);
1327 if (iov_iter_count(iter) < total) {
1328 /* Packet will be striped */
1329 pi.flags |= TUN_PKT_STRIP;
1330 }
1331
1332 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
1333 return -EFAULT;
1334 }
1335
1336 if (vnet_hdr_sz) {
1337 struct virtio_net_hdr gso = { 0 }; /* no info leak */
1338 if (iov_iter_count(iter) < vnet_hdr_sz)
1339 return -EINVAL;
1340
1341 if (skb_is_gso(skb)) {
1342 struct skb_shared_info *sinfo = skb_shinfo(skb);
1343
1344 /* This is a hint as to how much should be linear. */
1345 gso.hdr_len = cpu_to_tun16(tun, skb_headlen(skb));
1346 gso.gso_size = cpu_to_tun16(tun, sinfo->gso_size);
1347 if (sinfo->gso_type & SKB_GSO_TCPV4)
1348 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
1349 else if (sinfo->gso_type & SKB_GSO_TCPV6)
1350 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
1351 else if (sinfo->gso_type & SKB_GSO_UDP)
1352 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
1353 else {
1354 pr_err("unexpected GSO type: "
1355 "0x%x, gso_size %d, hdr_len %d\n",
1356 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
1357 tun16_to_cpu(tun, gso.hdr_len));
1358 print_hex_dump(KERN_ERR, "tun: ",
1359 DUMP_PREFIX_NONE,
1360 16, 1, skb->head,
1361 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
1362 WARN_ON_ONCE(1);
1363 return -EINVAL;
1364 }
1365 if (sinfo->gso_type & SKB_GSO_TCP_ECN)
1366 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
1367 } else
1368 gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
1369
1370 if (skb->ip_summed == CHECKSUM_PARTIAL) {
1371 gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
1372 gso.csum_start = cpu_to_tun16(tun, skb_checksum_start_offset(skb) +
1373 vlan_hlen);
1374 gso.csum_offset = cpu_to_tun16(tun, skb->csum_offset);
1375 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
1376 gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
1377 } /* else everything is zero */
1378
1379 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
1380 return -EFAULT;
1381
1382 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
1383 }
1384
1385 if (vlan_hlen) {
1386 int ret;
1387 struct {
1388 __be16 h_vlan_proto;
1389 __be16 h_vlan_TCI;
1390 } veth;
1391
1392 veth.h_vlan_proto = skb->vlan_proto;
1393 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
1394
1395 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
1396
1397 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
1398 if (ret || !iov_iter_count(iter))
1399 goto done;
1400
1401 ret = copy_to_iter(&veth, sizeof(veth), iter);
1402 if (ret != sizeof(veth) || !iov_iter_count(iter))
1403 goto done;
1404 }
1405
1406 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
1407
1408done:
1409 tun->dev->stats.tx_packets++;
1410 tun->dev->stats.tx_bytes += skb->len + vlan_hlen;
1411
1412 return total;
1413}
1414
1415static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
1416 struct iov_iter *to,
1417 int noblock)
1418{
1419 struct sk_buff *skb;
1420 ssize_t ret;
1421 int peeked, err, off = 0;
1422
1423 tun_debug(KERN_INFO, tun, "tun_do_read\n");
1424
1425 if (!iov_iter_count(to))
1426 return 0;
1427
1428 if (tun->dev->reg_state != NETREG_REGISTERED)
1429 return -EIO;
1430
1431 /* Read frames from queue */
1432 skb = __skb_recv_datagram(tfile->socket.sk, noblock ? MSG_DONTWAIT : 0,
1433 &peeked, &off, &err);
1434 if (!skb)
1435 return err;
1436
1437 ret = tun_put_user(tun, tfile, skb, to);
1438 if (unlikely(ret < 0))
1439 kfree_skb(skb);
1440 else
1441 consume_skb(skb);
1442
1443 return ret;
1444}
1445
1446static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
1447{
1448 struct file *file = iocb->ki_filp;
1449 struct tun_file *tfile = file->private_data;
1450 struct tun_struct *tun = __tun_get(tfile);
1451 ssize_t len = iov_iter_count(to), ret;
1452
1453 if (!tun)
1454 return -EBADFD;
1455 ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK);
1456 ret = min_t(ssize_t, ret, len);
1457 if (ret > 0)
1458 iocb->ki_pos = ret;
1459 tun_put(tun);
1460 return ret;
1461}
1462
1463static void tun_free_netdev(struct net_device *dev)
1464{
1465 struct tun_struct *tun = netdev_priv(dev);
1466
1467 BUG_ON(!(list_empty(&tun->disabled)));
1468 tun_flow_uninit(tun);
1469 security_tun_dev_free_security(tun->security);
1470 free_netdev(dev);
1471}
1472
1473static void tun_setup(struct net_device *dev)
1474{
1475 struct tun_struct *tun = netdev_priv(dev);
1476
1477 tun->owner = INVALID_UID;
1478 tun->group = INVALID_GID;
1479
1480 dev->ethtool_ops = &tun_ethtool_ops;
1481 dev->destructor = tun_free_netdev;
1482 /* We prefer our own queue length */
1483 dev->tx_queue_len = TUN_READQ_SIZE;
1484}
1485
1486/* Trivial set of netlink ops to allow deleting tun or tap
1487 * device with netlink.
1488 */
1489static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
1490{
1491 return -EINVAL;
1492}
1493
1494static struct rtnl_link_ops tun_link_ops __read_mostly = {
1495 .kind = DRV_NAME,
1496 .priv_size = sizeof(struct tun_struct),
1497 .setup = tun_setup,
1498 .validate = tun_validate,
1499};
1500
1501static void tun_sock_write_space(struct sock *sk)
1502{
1503 struct tun_file *tfile;
1504 wait_queue_head_t *wqueue;
1505
1506 if (!sock_writeable(sk))
1507 return;
1508
1509 if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
1510 return;
1511
1512 wqueue = sk_sleep(sk);
1513 if (wqueue && waitqueue_active(wqueue))
1514 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1515 POLLWRNORM | POLLWRBAND);
1516
1517 tfile = container_of(sk, struct tun_file, sk);
1518 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
1519}
1520
1521static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
1522{
1523 int ret;
1524 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1525 struct tun_struct *tun = __tun_get(tfile);
1526
1527 if (!tun)
1528 return -EBADFD;
1529
1530 ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter,
1531 m->msg_flags & MSG_DONTWAIT);
1532 tun_put(tun);
1533 return ret;
1534}
1535
1536static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
1537 int flags)
1538{
1539 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1540 struct tun_struct *tun = __tun_get(tfile);
1541 int ret;
1542
1543 if (!tun)
1544 return -EBADFD;
1545
1546 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
1547 ret = -EINVAL;
1548 goto out;
1549 }
1550 if (flags & MSG_ERRQUEUE) {
1551 ret = sock_recv_errqueue(sock->sk, m, total_len,
1552 SOL_PACKET, TUN_TX_TIMESTAMP);
1553 goto out;
1554 }
1555 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT);
1556 if (ret > (ssize_t)total_len) {
1557 m->msg_flags |= MSG_TRUNC;
1558 ret = flags & MSG_TRUNC ? ret : total_len;
1559 }
1560out:
1561 tun_put(tun);
1562 return ret;
1563}
1564
1565/* Ops structure to mimic raw sockets with tun */
1566static const struct proto_ops tun_socket_ops = {
1567 .sendmsg = tun_sendmsg,
1568 .recvmsg = tun_recvmsg,
1569};
1570
1571static struct proto tun_proto = {
1572 .name = "tun",
1573 .owner = THIS_MODULE,
1574 .obj_size = sizeof(struct tun_file),
1575};
1576
1577static int tun_flags(struct tun_struct *tun)
1578{
1579 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
1580}
1581
1582static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1583 char *buf)
1584{
1585 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1586 return sprintf(buf, "0x%x\n", tun_flags(tun));
1587}
1588
1589static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1590 char *buf)
1591{
1592 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1593 return uid_valid(tun->owner)?
1594 sprintf(buf, "%u\n",
1595 from_kuid_munged(current_user_ns(), tun->owner)):
1596 sprintf(buf, "-1\n");
1597}
1598
1599static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1600 char *buf)
1601{
1602 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1603 return gid_valid(tun->group) ?
1604 sprintf(buf, "%u\n",
1605 from_kgid_munged(current_user_ns(), tun->group)):
1606 sprintf(buf, "-1\n");
1607}
1608
1609static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1610static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1611static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1612
1613static struct attribute *tun_dev_attrs[] = {
1614 &dev_attr_tun_flags.attr,
1615 &dev_attr_owner.attr,
1616 &dev_attr_group.attr,
1617 NULL
1618};
1619
1620static const struct attribute_group tun_attr_group = {
1621 .attrs = tun_dev_attrs
1622};
1623
1624static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1625{
1626 struct tun_struct *tun;
1627 struct tun_file *tfile = file->private_data;
1628 struct net_device *dev;
1629 int err;
1630
1631 if (tfile->detached)
1632 return -EINVAL;
1633
1634 dev = __dev_get_by_name(net, ifr->ifr_name);
1635 if (dev) {
1636 if (ifr->ifr_flags & IFF_TUN_EXCL)
1637 return -EBUSY;
1638 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1639 tun = netdev_priv(dev);
1640 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1641 tun = netdev_priv(dev);
1642 else
1643 return -EINVAL;
1644
1645 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
1646 !!(tun->flags & IFF_MULTI_QUEUE))
1647 return -EINVAL;
1648
1649 if (tun_not_capable(tun))
1650 return -EPERM;
1651 err = security_tun_dev_open(tun->security);
1652 if (err < 0)
1653 return err;
1654
1655 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER);
1656 if (err < 0)
1657 return err;
1658
1659 if (tun->flags & IFF_MULTI_QUEUE &&
1660 (tun->numqueues + tun->numdisabled > 1)) {
1661 /* One or more queue has already been attached, no need
1662 * to initialize the device again.
1663 */
1664 return 0;
1665 }
1666 }
1667 else {
1668 char *name;
1669 unsigned long flags = 0;
1670 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
1671 MAX_TAP_QUEUES : 1;
1672
1673 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1674 return -EPERM;
1675 err = security_tun_dev_create();
1676 if (err < 0)
1677 return err;
1678
1679 /* Set dev type */
1680 if (ifr->ifr_flags & IFF_TUN) {
1681 /* TUN device */
1682 flags |= IFF_TUN;
1683 name = "tun%d";
1684 } else if (ifr->ifr_flags & IFF_TAP) {
1685 /* TAP device */
1686 flags |= IFF_TAP;
1687 name = "tap%d";
1688 } else
1689 return -EINVAL;
1690
1691 if (*ifr->ifr_name)
1692 name = ifr->ifr_name;
1693
1694 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
1695 NET_NAME_UNKNOWN, tun_setup, queues,
1696 queues);
1697
1698 if (!dev)
1699 return -ENOMEM;
1700
1701 dev_net_set(dev, net);
1702 dev->rtnl_link_ops = &tun_link_ops;
1703 dev->ifindex = tfile->ifindex;
1704 dev->sysfs_groups[0] = &tun_attr_group;
1705
1706 tun = netdev_priv(dev);
1707 tun->dev = dev;
1708 tun->flags = flags;
1709 tun->txflt.count = 0;
1710 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1711
1712 tun->align = NET_SKB_PAD;
1713 tun->filter_attached = false;
1714 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
1715
1716 spin_lock_init(&tun->lock);
1717
1718 err = security_tun_dev_alloc_security(&tun->security);
1719 if (err < 0)
1720 goto err_free_dev;
1721
1722 tun_net_init(dev);
1723 tun_flow_init(tun);
1724
1725 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1726 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
1727 NETIF_F_HW_VLAN_STAG_TX;
1728 dev->features = dev->hw_features;
1729 dev->vlan_features = dev->features &
1730 ~(NETIF_F_HW_VLAN_CTAG_TX |
1731 NETIF_F_HW_VLAN_STAG_TX);
1732
1733 INIT_LIST_HEAD(&tun->disabled);
1734 err = tun_attach(tun, file, false);
1735 if (err < 0)
1736 goto err_free_flow;
1737
1738 err = register_netdevice(tun->dev);
1739 if (err < 0)
1740 goto err_detach;
1741 }
1742
1743 netif_carrier_on(tun->dev);
1744
1745 tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1746
1747 tun->flags = (tun->flags & ~TUN_FEATURES) |
1748 (ifr->ifr_flags & TUN_FEATURES);
1749
1750 /* Make sure persistent devices do not get stuck in
1751 * xoff state.
1752 */
1753 if (netif_running(tun->dev))
1754 netif_tx_wake_all_queues(tun->dev);
1755
1756 strcpy(ifr->ifr_name, tun->dev->name);
1757 return 0;
1758
1759err_detach:
1760 tun_detach_all(dev);
1761err_free_flow:
1762 tun_flow_uninit(tun);
1763 security_tun_dev_free_security(tun->security);
1764err_free_dev:
1765 free_netdev(dev);
1766 return err;
1767}
1768
1769static void tun_get_iff(struct net *net, struct tun_struct *tun,
1770 struct ifreq *ifr)
1771{
1772 tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1773
1774 strcpy(ifr->ifr_name, tun->dev->name);
1775
1776 ifr->ifr_flags = tun_flags(tun);
1777
1778}
1779
1780/* This is like a cut-down ethtool ops, except done via tun fd so no
1781 * privs required. */
1782static int set_offload(struct tun_struct *tun, unsigned long arg)
1783{
1784 netdev_features_t features = 0;
1785
1786 if (arg & TUN_F_CSUM) {
1787 features |= NETIF_F_HW_CSUM;
1788 arg &= ~TUN_F_CSUM;
1789
1790 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1791 if (arg & TUN_F_TSO_ECN) {
1792 features |= NETIF_F_TSO_ECN;
1793 arg &= ~TUN_F_TSO_ECN;
1794 }
1795 if (arg & TUN_F_TSO4)
1796 features |= NETIF_F_TSO;
1797 if (arg & TUN_F_TSO6)
1798 features |= NETIF_F_TSO6;
1799 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1800 }
1801
1802 if (arg & TUN_F_UFO) {
1803 features |= NETIF_F_UFO;
1804 arg &= ~TUN_F_UFO;
1805 }
1806 }
1807
1808 /* This gives the user a way to test for new features in future by
1809 * trying to set them. */
1810 if (arg)
1811 return -EINVAL;
1812
1813 tun->set_features = features;
1814 netdev_update_features(tun->dev);
1815
1816 return 0;
1817}
1818
1819static void tun_detach_filter(struct tun_struct *tun, int n)
1820{
1821 int i;
1822 struct tun_file *tfile;
1823
1824 for (i = 0; i < n; i++) {
1825 tfile = rtnl_dereference(tun->tfiles[i]);
1826 __sk_detach_filter(tfile->socket.sk, lockdep_rtnl_is_held());
1827 }
1828
1829 tun->filter_attached = false;
1830}
1831
1832static int tun_attach_filter(struct tun_struct *tun)
1833{
1834 int i, ret = 0;
1835 struct tun_file *tfile;
1836
1837 for (i = 0; i < tun->numqueues; i++) {
1838 tfile = rtnl_dereference(tun->tfiles[i]);
1839 ret = __sk_attach_filter(&tun->fprog, tfile->socket.sk,
1840 lockdep_rtnl_is_held());
1841 if (ret) {
1842 tun_detach_filter(tun, i);
1843 return ret;
1844 }
1845 }
1846
1847 tun->filter_attached = true;
1848 return ret;
1849}
1850
1851static void tun_set_sndbuf(struct tun_struct *tun)
1852{
1853 struct tun_file *tfile;
1854 int i;
1855
1856 for (i = 0; i < tun->numqueues; i++) {
1857 tfile = rtnl_dereference(tun->tfiles[i]);
1858 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
1859 }
1860}
1861
1862static int tun_set_queue(struct file *file, struct ifreq *ifr)
1863{
1864 struct tun_file *tfile = file->private_data;
1865 struct tun_struct *tun;
1866 int ret = 0;
1867
1868 rtnl_lock();
1869
1870 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
1871 tun = tfile->detached;
1872 if (!tun) {
1873 ret = -EINVAL;
1874 goto unlock;
1875 }
1876 ret = security_tun_dev_attach_queue(tun->security);
1877 if (ret < 0)
1878 goto unlock;
1879 ret = tun_attach(tun, file, false);
1880 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
1881 tun = rtnl_dereference(tfile->tun);
1882 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
1883 ret = -EINVAL;
1884 else
1885 __tun_detach(tfile, false);
1886 } else
1887 ret = -EINVAL;
1888
1889unlock:
1890 rtnl_unlock();
1891 return ret;
1892}
1893
1894static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1895 unsigned long arg, int ifreq_len)
1896{
1897 struct tun_file *tfile = file->private_data;
1898 struct tun_struct *tun;
1899 void __user* argp = (void __user*)arg;
1900 struct ifreq ifr;
1901 kuid_t owner;
1902 kgid_t group;
1903 int sndbuf;
1904 int vnet_hdr_sz;
1905 unsigned int ifindex;
1906 int le;
1907 int ret;
1908
1909 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) {
1910 if (copy_from_user(&ifr, argp, ifreq_len))
1911 return -EFAULT;
1912 } else {
1913 memset(&ifr, 0, sizeof(ifr));
1914 }
1915 if (cmd == TUNGETFEATURES) {
1916 /* Currently this just means: "what IFF flags are valid?".
1917 * This is needed because we never checked for invalid flags on
1918 * TUNSETIFF.
1919 */
1920 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
1921 (unsigned int __user*)argp);
1922 } else if (cmd == TUNSETQUEUE)
1923 return tun_set_queue(file, &ifr);
1924
1925 ret = 0;
1926 rtnl_lock();
1927
1928 tun = __tun_get(tfile);
1929 if (cmd == TUNSETIFF && !tun) {
1930 ifr.ifr_name[IFNAMSIZ-1] = '\0';
1931
1932 ret = tun_set_iff(sock_net(&tfile->sk), file, &ifr);
1933
1934 if (ret)
1935 goto unlock;
1936
1937 if (copy_to_user(argp, &ifr, ifreq_len))
1938 ret = -EFAULT;
1939 goto unlock;
1940 }
1941 if (cmd == TUNSETIFINDEX) {
1942 ret = -EPERM;
1943 if (tun)
1944 goto unlock;
1945
1946 ret = -EFAULT;
1947 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
1948 goto unlock;
1949
1950 ret = 0;
1951 tfile->ifindex = ifindex;
1952 goto unlock;
1953 }
1954
1955 ret = -EBADFD;
1956 if (!tun)
1957 goto unlock;
1958
1959 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
1960
1961 ret = 0;
1962 switch (cmd) {
1963 case TUNGETIFF:
1964 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1965
1966 if (tfile->detached)
1967 ifr.ifr_flags |= IFF_DETACH_QUEUE;
1968 if (!tfile->socket.sk->sk_filter)
1969 ifr.ifr_flags |= IFF_NOFILTER;
1970
1971 if (copy_to_user(argp, &ifr, ifreq_len))
1972 ret = -EFAULT;
1973 break;
1974
1975 case TUNSETNOCSUM:
1976 /* Disable/Enable checksum */
1977
1978 /* [unimplemented] */
1979 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
1980 arg ? "disabled" : "enabled");
1981 break;
1982
1983 case TUNSETPERSIST:
1984 /* Disable/Enable persist mode. Keep an extra reference to the
1985 * module to prevent the module being unprobed.
1986 */
1987 if (arg && !(tun->flags & IFF_PERSIST)) {
1988 tun->flags |= IFF_PERSIST;
1989 __module_get(THIS_MODULE);
1990 }
1991 if (!arg && (tun->flags & IFF_PERSIST)) {
1992 tun->flags &= ~IFF_PERSIST;
1993 module_put(THIS_MODULE);
1994 }
1995
1996 tun_debug(KERN_INFO, tun, "persist %s\n",
1997 arg ? "enabled" : "disabled");
1998 break;
1999
2000 case TUNSETOWNER:
2001 /* Set owner of the device */
2002 owner = make_kuid(current_user_ns(), arg);
2003 if (!uid_valid(owner)) {
2004 ret = -EINVAL;
2005 break;
2006 }
2007 tun->owner = owner;
2008 tun_debug(KERN_INFO, tun, "owner set to %u\n",
2009 from_kuid(&init_user_ns, tun->owner));
2010 break;
2011
2012 case TUNSETGROUP:
2013 /* Set group of the device */
2014 group = make_kgid(current_user_ns(), arg);
2015 if (!gid_valid(group)) {
2016 ret = -EINVAL;
2017 break;
2018 }
2019 tun->group = group;
2020 tun_debug(KERN_INFO, tun, "group set to %u\n",
2021 from_kgid(&init_user_ns, tun->group));
2022 break;
2023
2024 case TUNSETLINK:
2025 /* Only allow setting the type when the interface is down */
2026 if (tun->dev->flags & IFF_UP) {
2027 tun_debug(KERN_INFO, tun,
2028 "Linktype set failed because interface is up\n");
2029 ret = -EBUSY;
2030 } else {
2031 tun->dev->type = (int) arg;
2032 tun_debug(KERN_INFO, tun, "linktype set to %d\n",
2033 tun->dev->type);
2034 ret = 0;
2035 }
2036 break;
2037
2038#ifdef TUN_DEBUG
2039 case TUNSETDEBUG:
2040 tun->debug = arg;
2041 break;
2042#endif
2043 case TUNSETOFFLOAD:
2044 ret = set_offload(tun, arg);
2045 break;
2046
2047 case TUNSETTXFILTER:
2048 /* Can be set only for TAPs */
2049 ret = -EINVAL;
2050 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2051 break;
2052 ret = update_filter(&tun->txflt, (void __user *)arg);
2053 break;
2054
2055 case SIOCGIFHWADDR:
2056 /* Get hw address */
2057 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
2058 ifr.ifr_hwaddr.sa_family = tun->dev->type;
2059 if (copy_to_user(argp, &ifr, ifreq_len))
2060 ret = -EFAULT;
2061 break;
2062
2063 case SIOCSIFHWADDR:
2064 /* Set hw address */
2065 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
2066 ifr.ifr_hwaddr.sa_data);
2067
2068 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
2069 break;
2070
2071 case TUNGETSNDBUF:
2072 sndbuf = tfile->socket.sk->sk_sndbuf;
2073 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
2074 ret = -EFAULT;
2075 break;
2076
2077 case TUNSETSNDBUF:
2078 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
2079 ret = -EFAULT;
2080 break;
2081 }
2082
2083 tun->sndbuf = sndbuf;
2084 tun_set_sndbuf(tun);
2085 break;
2086
2087 case TUNGETVNETHDRSZ:
2088 vnet_hdr_sz = tun->vnet_hdr_sz;
2089 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
2090 ret = -EFAULT;
2091 break;
2092
2093 case TUNSETVNETHDRSZ:
2094 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
2095 ret = -EFAULT;
2096 break;
2097 }
2098 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
2099 ret = -EINVAL;
2100 break;
2101 }
2102
2103 tun->vnet_hdr_sz = vnet_hdr_sz;
2104 break;
2105
2106 case TUNGETVNETLE:
2107 le = !!(tun->flags & TUN_VNET_LE);
2108 if (put_user(le, (int __user *)argp))
2109 ret = -EFAULT;
2110 break;
2111
2112 case TUNSETVNETLE:
2113 if (get_user(le, (int __user *)argp)) {
2114 ret = -EFAULT;
2115 break;
2116 }
2117 if (le)
2118 tun->flags |= TUN_VNET_LE;
2119 else
2120 tun->flags &= ~TUN_VNET_LE;
2121 break;
2122
2123 case TUNGETVNETBE:
2124 ret = tun_get_vnet_be(tun, argp);
2125 break;
2126
2127 case TUNSETVNETBE:
2128 ret = tun_set_vnet_be(tun, argp);
2129 break;
2130
2131 case TUNATTACHFILTER:
2132 /* Can be set only for TAPs */
2133 ret = -EINVAL;
2134 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2135 break;
2136 ret = -EFAULT;
2137 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
2138 break;
2139
2140 ret = tun_attach_filter(tun);
2141 break;
2142
2143 case TUNDETACHFILTER:
2144 /* Can be set only for TAPs */
2145 ret = -EINVAL;
2146 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2147 break;
2148 ret = 0;
2149 tun_detach_filter(tun, tun->numqueues);
2150 break;
2151
2152 case TUNGETFILTER:
2153 ret = -EINVAL;
2154 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
2155 break;
2156 ret = -EFAULT;
2157 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
2158 break;
2159 ret = 0;
2160 break;
2161
2162 default:
2163 ret = -EINVAL;
2164 break;
2165 }
2166
2167unlock:
2168 rtnl_unlock();
2169 if (tun)
2170 tun_put(tun);
2171 return ret;
2172}
2173
2174static long tun_chr_ioctl(struct file *file,
2175 unsigned int cmd, unsigned long arg)
2176{
2177 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
2178}
2179
2180#ifdef CONFIG_COMPAT
2181static long tun_chr_compat_ioctl(struct file *file,
2182 unsigned int cmd, unsigned long arg)
2183{
2184 switch (cmd) {
2185 case TUNSETIFF:
2186 case TUNGETIFF:
2187 case TUNSETTXFILTER:
2188 case TUNGETSNDBUF:
2189 case TUNSETSNDBUF:
2190 case SIOCGIFHWADDR:
2191 case SIOCSIFHWADDR:
2192 arg = (unsigned long)compat_ptr(arg);
2193 break;
2194 default:
2195 arg = (compat_ulong_t)arg;
2196 break;
2197 }
2198
2199 /*
2200 * compat_ifreq is shorter than ifreq, so we must not access beyond
2201 * the end of that structure. All fields that are used in this
2202 * driver are compatible though, we don't need to convert the
2203 * contents.
2204 */
2205 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
2206}
2207#endif /* CONFIG_COMPAT */
2208
2209static int tun_chr_fasync(int fd, struct file *file, int on)
2210{
2211 struct tun_file *tfile = file->private_data;
2212 int ret;
2213
2214 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
2215 goto out;
2216
2217 if (on) {
2218 __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
2219 tfile->flags |= TUN_FASYNC;
2220 } else
2221 tfile->flags &= ~TUN_FASYNC;
2222 ret = 0;
2223out:
2224 return ret;
2225}
2226
2227static int tun_chr_open(struct inode *inode, struct file * file)
2228{
2229 struct net *net = current->nsproxy->net_ns;
2230 struct tun_file *tfile;
2231
2232 DBG1(KERN_INFO, "tunX: tun_chr_open\n");
2233
2234 tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
2235 &tun_proto, 0);
2236 if (!tfile)
2237 return -ENOMEM;
2238 RCU_INIT_POINTER(tfile->tun, NULL);
2239 tfile->flags = 0;
2240 tfile->ifindex = 0;
2241
2242 init_waitqueue_head(&tfile->wq.wait);
2243 RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq);
2244
2245 tfile->socket.file = file;
2246 tfile->socket.ops = &tun_socket_ops;
2247
2248 sock_init_data(&tfile->socket, &tfile->sk);
2249
2250 tfile->sk.sk_write_space = tun_sock_write_space;
2251 tfile->sk.sk_sndbuf = INT_MAX;
2252
2253 file->private_data = tfile;
2254 INIT_LIST_HEAD(&tfile->next);
2255
2256 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
2257
2258 return 0;
2259}
2260
2261static int tun_chr_close(struct inode *inode, struct file *file)
2262{
2263 struct tun_file *tfile = file->private_data;
2264
2265 tun_detach(tfile, true);
2266
2267 return 0;
2268}
2269
2270#ifdef CONFIG_PROC_FS
2271static void tun_chr_show_fdinfo(struct seq_file *m, struct file *f)
2272{
2273 struct tun_struct *tun;
2274 struct ifreq ifr;
2275
2276 memset(&ifr, 0, sizeof(ifr));
2277
2278 rtnl_lock();
2279 tun = tun_get(f);
2280 if (tun)
2281 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2282 rtnl_unlock();
2283
2284 if (tun)
2285 tun_put(tun);
2286
2287 seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
2288}
2289#endif
2290
2291static const struct file_operations tun_fops = {
2292 .owner = THIS_MODULE,
2293 .llseek = no_llseek,
2294 .read_iter = tun_chr_read_iter,
2295 .write_iter = tun_chr_write_iter,
2296 .poll = tun_chr_poll,
2297 .unlocked_ioctl = tun_chr_ioctl,
2298#ifdef CONFIG_COMPAT
2299 .compat_ioctl = tun_chr_compat_ioctl,
2300#endif
2301 .open = tun_chr_open,
2302 .release = tun_chr_close,
2303 .fasync = tun_chr_fasync,
2304#ifdef CONFIG_PROC_FS
2305 .show_fdinfo = tun_chr_show_fdinfo,
2306#endif
2307};
2308
2309static struct miscdevice tun_miscdev = {
2310 .minor = TUN_MINOR,
2311 .name = "tun",
2312 .nodename = "net/tun",
2313 .fops = &tun_fops,
2314};
2315
2316/* ethtool interface */
2317
2318static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
2319{
2320 cmd->supported = 0;
2321 cmd->advertising = 0;
2322 ethtool_cmd_speed_set(cmd, SPEED_10);
2323 cmd->duplex = DUPLEX_FULL;
2324 cmd->port = PORT_TP;
2325 cmd->phy_address = 0;
2326 cmd->transceiver = XCVR_INTERNAL;
2327 cmd->autoneg = AUTONEG_DISABLE;
2328 cmd->maxtxpkt = 0;
2329 cmd->maxrxpkt = 0;
2330 return 0;
2331}
2332
2333static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
2334{
2335 struct tun_struct *tun = netdev_priv(dev);
2336
2337 strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
2338 strlcpy(info->version, DRV_VERSION, sizeof(info->version));
2339
2340 switch (tun->flags & TUN_TYPE_MASK) {
2341 case IFF_TUN:
2342 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
2343 break;
2344 case IFF_TAP:
2345 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
2346 break;
2347 }
2348}
2349
2350static u32 tun_get_msglevel(struct net_device *dev)
2351{
2352#ifdef TUN_DEBUG
2353 struct tun_struct *tun = netdev_priv(dev);
2354 return tun->debug;
2355#else
2356 return -EOPNOTSUPP;
2357#endif
2358}
2359
2360static void tun_set_msglevel(struct net_device *dev, u32 value)
2361{
2362#ifdef TUN_DEBUG
2363 struct tun_struct *tun = netdev_priv(dev);
2364 tun->debug = value;
2365#endif
2366}
2367
2368static const struct ethtool_ops tun_ethtool_ops = {
2369 .get_settings = tun_get_settings,
2370 .get_drvinfo = tun_get_drvinfo,
2371 .get_msglevel = tun_get_msglevel,
2372 .set_msglevel = tun_set_msglevel,
2373 .get_link = ethtool_op_get_link,
2374 .get_ts_info = ethtool_op_get_ts_info,
2375};
2376
2377
2378static int __init tun_init(void)
2379{
2380 int ret = 0;
2381
2382 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
2383 pr_info("%s\n", DRV_COPYRIGHT);
2384
2385 ret = rtnl_link_register(&tun_link_ops);
2386 if (ret) {
2387 pr_err("Can't register link_ops\n");
2388 goto err_linkops;
2389 }
2390
2391 ret = misc_register(&tun_miscdev);
2392 if (ret) {
2393 pr_err("Can't register misc device %d\n", TUN_MINOR);
2394 goto err_misc;
2395 }
2396 return 0;
2397err_misc:
2398 rtnl_link_unregister(&tun_link_ops);
2399err_linkops:
2400 return ret;
2401}
2402
2403static void tun_cleanup(void)
2404{
2405 misc_deregister(&tun_miscdev);
2406 rtnl_link_unregister(&tun_link_ops);
2407}
2408
2409/* Get an underlying socket object from tun file. Returns error unless file is
2410 * attached to a device. The returned object works like a packet socket, it
2411 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
2412 * holding a reference to the file for as long as the socket is in use. */
2413struct socket *tun_get_socket(struct file *file)
2414{
2415 struct tun_file *tfile;
2416 if (file->f_op != &tun_fops)
2417 return ERR_PTR(-EINVAL);
2418 tfile = file->private_data;
2419 if (!tfile)
2420 return ERR_PTR(-EBADFD);
2421 return &tfile->socket;
2422}
2423EXPORT_SYMBOL_GPL(tun_get_socket);
2424
2425module_init(tun_init);
2426module_exit(tun_cleanup);
2427MODULE_DESCRIPTION(DRV_DESCRIPTION);
2428MODULE_AUTHOR(DRV_COPYRIGHT);
2429MODULE_LICENSE("GPL");
2430MODULE_ALIAS_MISCDEV(TUN_MINOR);
2431MODULE_ALIAS("devname:net/tun");