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1/*
2 * TUN - Universal TUN/TAP device driver.
3 * Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
16 */
17
18/*
19 * Changes:
20 *
21 * Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
22 * Add TUNSETLINK ioctl to set the link encapsulation
23 *
24 * Mark Smith <markzzzsmith@yahoo.com.au>
25 * Use eth_random_addr() for tap MAC address.
26 *
27 * Harald Roelle <harald.roelle@ifi.lmu.de> 2004/04/20
28 * Fixes in packet dropping, queue length setting and queue wakeup.
29 * Increased default tx queue length.
30 * Added ethtool API.
31 * Minor cleanups
32 *
33 * Daniel Podlejski <underley@underley.eu.org>
34 * Modifications for 2.3.99-pre5 kernel.
35 */
36
37#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
38
39#define DRV_NAME "tun"
40#define DRV_VERSION "1.6"
41#define DRV_DESCRIPTION "Universal TUN/TAP device driver"
42#define DRV_COPYRIGHT "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
43
44#include <linux/module.h>
45#include <linux/errno.h>
46#include <linux/kernel.h>
47#include <linux/sched/signal.h>
48#include <linux/major.h>
49#include <linux/slab.h>
50#include <linux/poll.h>
51#include <linux/fcntl.h>
52#include <linux/init.h>
53#include <linux/skbuff.h>
54#include <linux/netdevice.h>
55#include <linux/etherdevice.h>
56#include <linux/miscdevice.h>
57#include <linux/ethtool.h>
58#include <linux/rtnetlink.h>
59#include <linux/compat.h>
60#include <linux/if.h>
61#include <linux/if_arp.h>
62#include <linux/if_ether.h>
63#include <linux/if_tun.h>
64#include <linux/if_vlan.h>
65#include <linux/crc32.h>
66#include <linux/nsproxy.h>
67#include <linux/virtio_net.h>
68#include <linux/rcupdate.h>
69#include <net/net_namespace.h>
70#include <net/netns/generic.h>
71#include <net/rtnetlink.h>
72#include <net/sock.h>
73#include <linux/seq_file.h>
74#include <linux/uio.h>
75#include <linux/skb_array.h>
76#include <linux/bpf.h>
77#include <linux/bpf_trace.h>
78#include <linux/mutex.h>
79
80#include <linux/uaccess.h>
81#include <linux/proc_fs.h>
82
83/* Uncomment to enable debugging */
84/* #define TUN_DEBUG 1 */
85
86#ifdef TUN_DEBUG
87static int debug;
88
89#define tun_debug(level, tun, fmt, args...) \
90do { \
91 if (tun->debug) \
92 netdev_printk(level, tun->dev, fmt, ##args); \
93} while (0)
94#define DBG1(level, fmt, args...) \
95do { \
96 if (debug == 2) \
97 printk(level fmt, ##args); \
98} while (0)
99#else
100#define tun_debug(level, tun, fmt, args...) \
101do { \
102 if (0) \
103 netdev_printk(level, tun->dev, fmt, ##args); \
104} while (0)
105#define DBG1(level, fmt, args...) \
106do { \
107 if (0) \
108 printk(level fmt, ##args); \
109} while (0)
110#endif
111
112#define TUN_HEADROOM 256
113#define TUN_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
114
115/* TUN device flags */
116
117/* IFF_ATTACH_QUEUE is never stored in device flags,
118 * overload it to mean fasync when stored there.
119 */
120#define TUN_FASYNC IFF_ATTACH_QUEUE
121/* High bits in flags field are unused. */
122#define TUN_VNET_LE 0x80000000
123#define TUN_VNET_BE 0x40000000
124
125#define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
126 IFF_MULTI_QUEUE | IFF_NAPI | IFF_NAPI_FRAGS)
127
128#define GOODCOPY_LEN 128
129
130#define FLT_EXACT_COUNT 8
131struct tap_filter {
132 unsigned int count; /* Number of addrs. Zero means disabled */
133 u32 mask[2]; /* Mask of the hashed addrs */
134 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
135};
136
137/* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
138 * to max number of VCPUs in guest. */
139#define MAX_TAP_QUEUES 256
140#define MAX_TAP_FLOWS 4096
141
142#define TUN_FLOW_EXPIRE (3 * HZ)
143
144struct tun_pcpu_stats {
145 u64 rx_packets;
146 u64 rx_bytes;
147 u64 tx_packets;
148 u64 tx_bytes;
149 struct u64_stats_sync syncp;
150 u32 rx_dropped;
151 u32 tx_dropped;
152 u32 rx_frame_errors;
153};
154
155/* A tun_file connects an open character device to a tuntap netdevice. It
156 * also contains all socket related structures (except sock_fprog and tap_filter)
157 * to serve as one transmit queue for tuntap device. The sock_fprog and
158 * tap_filter were kept in tun_struct since they were used for filtering for the
159 * netdevice not for a specific queue (at least I didn't see the requirement for
160 * this).
161 *
162 * RCU usage:
163 * The tun_file and tun_struct are loosely coupled, the pointer from one to the
164 * other can only be read while rcu_read_lock or rtnl_lock is held.
165 */
166struct tun_file {
167 struct sock sk;
168 struct socket socket;
169 struct socket_wq wq;
170 struct tun_struct __rcu *tun;
171 struct fasync_struct *fasync;
172 /* only used for fasnyc */
173 unsigned int flags;
174 union {
175 u16 queue_index;
176 unsigned int ifindex;
177 };
178 struct napi_struct napi;
179 bool napi_enabled;
180 struct mutex napi_mutex; /* Protects access to the above napi */
181 struct list_head next;
182 struct tun_struct *detached;
183 struct ptr_ring tx_ring;
184 struct xdp_rxq_info xdp_rxq;
185};
186
187struct tun_flow_entry {
188 struct hlist_node hash_link;
189 struct rcu_head rcu;
190 struct tun_struct *tun;
191
192 u32 rxhash;
193 u32 rps_rxhash;
194 int queue_index;
195 unsigned long updated;
196};
197
198#define TUN_NUM_FLOW_ENTRIES 1024
199
200struct tun_prog {
201 struct rcu_head rcu;
202 struct bpf_prog *prog;
203};
204
205/* Since the socket were moved to tun_file, to preserve the behavior of persist
206 * device, socket filter, sndbuf and vnet header size were restore when the
207 * file were attached to a persist device.
208 */
209struct tun_struct {
210 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES];
211 unsigned int numqueues;
212 unsigned int flags;
213 kuid_t owner;
214 kgid_t group;
215
216 struct net_device *dev;
217 netdev_features_t set_features;
218#define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
219 NETIF_F_TSO6)
220
221 int align;
222 int vnet_hdr_sz;
223 int sndbuf;
224 struct tap_filter txflt;
225 struct sock_fprog fprog;
226 /* protected by rtnl lock */
227 bool filter_attached;
228#ifdef TUN_DEBUG
229 int debug;
230#endif
231 spinlock_t lock;
232 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
233 struct timer_list flow_gc_timer;
234 unsigned long ageing_time;
235 unsigned int numdisabled;
236 struct list_head disabled;
237 void *security;
238 u32 flow_count;
239 u32 rx_batched;
240 struct tun_pcpu_stats __percpu *pcpu_stats;
241 struct bpf_prog __rcu *xdp_prog;
242 struct tun_prog __rcu *steering_prog;
243 struct tun_prog __rcu *filter_prog;
244};
245
246struct veth {
247 __be16 h_vlan_proto;
248 __be16 h_vlan_TCI;
249};
250
251bool tun_is_xdp_buff(void *ptr)
252{
253 return (unsigned long)ptr & TUN_XDP_FLAG;
254}
255EXPORT_SYMBOL(tun_is_xdp_buff);
256
257void *tun_xdp_to_ptr(void *ptr)
258{
259 return (void *)((unsigned long)ptr | TUN_XDP_FLAG);
260}
261EXPORT_SYMBOL(tun_xdp_to_ptr);
262
263void *tun_ptr_to_xdp(void *ptr)
264{
265 return (void *)((unsigned long)ptr & ~TUN_XDP_FLAG);
266}
267EXPORT_SYMBOL(tun_ptr_to_xdp);
268
269static int tun_napi_receive(struct napi_struct *napi, int budget)
270{
271 struct tun_file *tfile = container_of(napi, struct tun_file, napi);
272 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
273 struct sk_buff_head process_queue;
274 struct sk_buff *skb;
275 int received = 0;
276
277 __skb_queue_head_init(&process_queue);
278
279 spin_lock(&queue->lock);
280 skb_queue_splice_tail_init(queue, &process_queue);
281 spin_unlock(&queue->lock);
282
283 while (received < budget && (skb = __skb_dequeue(&process_queue))) {
284 napi_gro_receive(napi, skb);
285 ++received;
286 }
287
288 if (!skb_queue_empty(&process_queue)) {
289 spin_lock(&queue->lock);
290 skb_queue_splice(&process_queue, queue);
291 spin_unlock(&queue->lock);
292 }
293
294 return received;
295}
296
297static int tun_napi_poll(struct napi_struct *napi, int budget)
298{
299 unsigned int received;
300
301 received = tun_napi_receive(napi, budget);
302
303 if (received < budget)
304 napi_complete_done(napi, received);
305
306 return received;
307}
308
309static void tun_napi_init(struct tun_struct *tun, struct tun_file *tfile,
310 bool napi_en)
311{
312 tfile->napi_enabled = napi_en;
313 if (napi_en) {
314 netif_napi_add(tun->dev, &tfile->napi, tun_napi_poll,
315 NAPI_POLL_WEIGHT);
316 napi_enable(&tfile->napi);
317 mutex_init(&tfile->napi_mutex);
318 }
319}
320
321static void tun_napi_disable(struct tun_struct *tun, struct tun_file *tfile)
322{
323 if (tfile->napi_enabled)
324 napi_disable(&tfile->napi);
325}
326
327static void tun_napi_del(struct tun_struct *tun, struct tun_file *tfile)
328{
329 if (tfile->napi_enabled)
330 netif_napi_del(&tfile->napi);
331}
332
333static bool tun_napi_frags_enabled(const struct tun_struct *tun)
334{
335 return READ_ONCE(tun->flags) & IFF_NAPI_FRAGS;
336}
337
338#ifdef CONFIG_TUN_VNET_CROSS_LE
339static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
340{
341 return tun->flags & TUN_VNET_BE ? false :
342 virtio_legacy_is_little_endian();
343}
344
345static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
346{
347 int be = !!(tun->flags & TUN_VNET_BE);
348
349 if (put_user(be, argp))
350 return -EFAULT;
351
352 return 0;
353}
354
355static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
356{
357 int be;
358
359 if (get_user(be, argp))
360 return -EFAULT;
361
362 if (be)
363 tun->flags |= TUN_VNET_BE;
364 else
365 tun->flags &= ~TUN_VNET_BE;
366
367 return 0;
368}
369#else
370static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
371{
372 return virtio_legacy_is_little_endian();
373}
374
375static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
376{
377 return -EINVAL;
378}
379
380static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
381{
382 return -EINVAL;
383}
384#endif /* CONFIG_TUN_VNET_CROSS_LE */
385
386static inline bool tun_is_little_endian(struct tun_struct *tun)
387{
388 return tun->flags & TUN_VNET_LE ||
389 tun_legacy_is_little_endian(tun);
390}
391
392static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
393{
394 return __virtio16_to_cpu(tun_is_little_endian(tun), val);
395}
396
397static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
398{
399 return __cpu_to_virtio16(tun_is_little_endian(tun), val);
400}
401
402static inline u32 tun_hashfn(u32 rxhash)
403{
404 return rxhash & 0x3ff;
405}
406
407static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
408{
409 struct tun_flow_entry *e;
410
411 hlist_for_each_entry_rcu(e, head, hash_link) {
412 if (e->rxhash == rxhash)
413 return e;
414 }
415 return NULL;
416}
417
418static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
419 struct hlist_head *head,
420 u32 rxhash, u16 queue_index)
421{
422 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
423
424 if (e) {
425 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
426 rxhash, queue_index);
427 e->updated = jiffies;
428 e->rxhash = rxhash;
429 e->rps_rxhash = 0;
430 e->queue_index = queue_index;
431 e->tun = tun;
432 hlist_add_head_rcu(&e->hash_link, head);
433 ++tun->flow_count;
434 }
435 return e;
436}
437
438static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
439{
440 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
441 e->rxhash, e->queue_index);
442 hlist_del_rcu(&e->hash_link);
443 kfree_rcu(e, rcu);
444 --tun->flow_count;
445}
446
447static void tun_flow_flush(struct tun_struct *tun)
448{
449 int i;
450
451 spin_lock_bh(&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 tun_flow_delete(tun, e);
458 }
459 spin_unlock_bh(&tun->lock);
460}
461
462static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
463{
464 int i;
465
466 spin_lock_bh(&tun->lock);
467 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
468 struct tun_flow_entry *e;
469 struct hlist_node *n;
470
471 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
472 if (e->queue_index == queue_index)
473 tun_flow_delete(tun, e);
474 }
475 }
476 spin_unlock_bh(&tun->lock);
477}
478
479static void tun_flow_cleanup(struct timer_list *t)
480{
481 struct tun_struct *tun = from_timer(tun, t, flow_gc_timer);
482 unsigned long delay = tun->ageing_time;
483 unsigned long next_timer = jiffies + delay;
484 unsigned long count = 0;
485 int i;
486
487 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
488
489 spin_lock(&tun->lock);
490 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
491 struct tun_flow_entry *e;
492 struct hlist_node *n;
493
494 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
495 unsigned long this_timer;
496
497 this_timer = e->updated + delay;
498 if (time_before_eq(this_timer, jiffies)) {
499 tun_flow_delete(tun, e);
500 continue;
501 }
502 count++;
503 if (time_before(this_timer, next_timer))
504 next_timer = this_timer;
505 }
506 }
507
508 if (count)
509 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
510 spin_unlock(&tun->lock);
511}
512
513static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
514 struct tun_file *tfile)
515{
516 struct hlist_head *head;
517 struct tun_flow_entry *e;
518 unsigned long delay = tun->ageing_time;
519 u16 queue_index = tfile->queue_index;
520
521 if (!rxhash)
522 return;
523 else
524 head = &tun->flows[tun_hashfn(rxhash)];
525
526 rcu_read_lock();
527
528 /* We may get a very small possibility of OOO during switching, not
529 * worth to optimize.*/
530 if (tun->numqueues == 1 || tfile->detached)
531 goto unlock;
532
533 e = tun_flow_find(head, rxhash);
534 if (likely(e)) {
535 /* TODO: keep queueing to old queue until it's empty? */
536 e->queue_index = queue_index;
537 e->updated = jiffies;
538 sock_rps_record_flow_hash(e->rps_rxhash);
539 } else {
540 spin_lock_bh(&tun->lock);
541 if (!tun_flow_find(head, rxhash) &&
542 tun->flow_count < MAX_TAP_FLOWS)
543 tun_flow_create(tun, head, rxhash, queue_index);
544
545 if (!timer_pending(&tun->flow_gc_timer))
546 mod_timer(&tun->flow_gc_timer,
547 round_jiffies_up(jiffies + delay));
548 spin_unlock_bh(&tun->lock);
549 }
550
551unlock:
552 rcu_read_unlock();
553}
554
555/**
556 * Save the hash received in the stack receive path and update the
557 * flow_hash table accordingly.
558 */
559static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
560{
561 if (unlikely(e->rps_rxhash != hash))
562 e->rps_rxhash = hash;
563}
564
565/* We try to identify a flow through its rxhash first. The reason that
566 * we do not check rxq no. is because some cards(e.g 82599), chooses
567 * the rxq based on the txq where the last packet of the flow comes. As
568 * the userspace application move between processors, we may get a
569 * different rxq no. here. If we could not get rxhash, then we would
570 * hope the rxq no. may help here.
571 */
572static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb)
573{
574 struct tun_flow_entry *e;
575 u32 txq = 0;
576 u32 numqueues = 0;
577
578 numqueues = READ_ONCE(tun->numqueues);
579
580 txq = __skb_get_hash_symmetric(skb);
581 if (txq) {
582 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
583 if (e) {
584 tun_flow_save_rps_rxhash(e, txq);
585 txq = e->queue_index;
586 } else
587 /* use multiply and shift instead of expensive divide */
588 txq = ((u64)txq * numqueues) >> 32;
589 } else if (likely(skb_rx_queue_recorded(skb))) {
590 txq = skb_get_rx_queue(skb);
591 while (unlikely(txq >= numqueues))
592 txq -= numqueues;
593 }
594
595 return txq;
596}
597
598static u16 tun_ebpf_select_queue(struct tun_struct *tun, struct sk_buff *skb)
599{
600 struct tun_prog *prog;
601 u16 ret = 0;
602
603 prog = rcu_dereference(tun->steering_prog);
604 if (prog)
605 ret = bpf_prog_run_clear_cb(prog->prog, skb);
606
607 return ret % tun->numqueues;
608}
609
610static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
611 void *accel_priv, select_queue_fallback_t fallback)
612{
613 struct tun_struct *tun = netdev_priv(dev);
614 u16 ret;
615
616 rcu_read_lock();
617 if (rcu_dereference(tun->steering_prog))
618 ret = tun_ebpf_select_queue(tun, skb);
619 else
620 ret = tun_automq_select_queue(tun, skb);
621 rcu_read_unlock();
622
623 return ret;
624}
625
626static inline bool tun_not_capable(struct tun_struct *tun)
627{
628 const struct cred *cred = current_cred();
629 struct net *net = dev_net(tun->dev);
630
631 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
632 (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
633 !ns_capable(net->user_ns, CAP_NET_ADMIN);
634}
635
636static void tun_set_real_num_queues(struct tun_struct *tun)
637{
638 netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
639 netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
640}
641
642static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
643{
644 tfile->detached = tun;
645 list_add_tail(&tfile->next, &tun->disabled);
646 ++tun->numdisabled;
647}
648
649static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
650{
651 struct tun_struct *tun = tfile->detached;
652
653 tfile->detached = NULL;
654 list_del_init(&tfile->next);
655 --tun->numdisabled;
656 return tun;
657}
658
659void tun_ptr_free(void *ptr)
660{
661 if (!ptr)
662 return;
663 if (tun_is_xdp_buff(ptr)) {
664 struct xdp_buff *xdp = tun_ptr_to_xdp(ptr);
665
666 put_page(virt_to_head_page(xdp->data));
667 } else {
668 __skb_array_destroy_skb(ptr);
669 }
670}
671EXPORT_SYMBOL_GPL(tun_ptr_free);
672
673static void tun_queue_purge(struct tun_file *tfile)
674{
675 void *ptr;
676
677 while ((ptr = ptr_ring_consume(&tfile->tx_ring)) != NULL)
678 tun_ptr_free(ptr);
679
680 skb_queue_purge(&tfile->sk.sk_write_queue);
681 skb_queue_purge(&tfile->sk.sk_error_queue);
682}
683
684static void __tun_detach(struct tun_file *tfile, bool clean)
685{
686 struct tun_file *ntfile;
687 struct tun_struct *tun;
688
689 tun = rtnl_dereference(tfile->tun);
690
691 if (tun && clean) {
692 tun_napi_disable(tun, tfile);
693 tun_napi_del(tun, tfile);
694 }
695
696 if (tun && !tfile->detached) {
697 u16 index = tfile->queue_index;
698 BUG_ON(index >= tun->numqueues);
699
700 rcu_assign_pointer(tun->tfiles[index],
701 tun->tfiles[tun->numqueues - 1]);
702 ntfile = rtnl_dereference(tun->tfiles[index]);
703 ntfile->queue_index = index;
704
705 --tun->numqueues;
706 if (clean) {
707 RCU_INIT_POINTER(tfile->tun, NULL);
708 sock_put(&tfile->sk);
709 } else
710 tun_disable_queue(tun, tfile);
711
712 synchronize_net();
713 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
714 /* Drop read queue */
715 tun_queue_purge(tfile);
716 tun_set_real_num_queues(tun);
717 } else if (tfile->detached && clean) {
718 tun = tun_enable_queue(tfile);
719 sock_put(&tfile->sk);
720 }
721
722 if (clean) {
723 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
724 netif_carrier_off(tun->dev);
725
726 if (!(tun->flags & IFF_PERSIST) &&
727 tun->dev->reg_state == NETREG_REGISTERED)
728 unregister_netdevice(tun->dev);
729 }
730 if (tun)
731 xdp_rxq_info_unreg(&tfile->xdp_rxq);
732 ptr_ring_cleanup(&tfile->tx_ring, tun_ptr_free);
733 sock_put(&tfile->sk);
734 }
735}
736
737static void tun_detach(struct tun_file *tfile, bool clean)
738{
739 struct tun_struct *tun;
740 struct net_device *dev;
741
742 rtnl_lock();
743 tun = rtnl_dereference(tfile->tun);
744 dev = tun ? tun->dev : NULL;
745 __tun_detach(tfile, clean);
746 if (dev)
747 netdev_state_change(dev);
748 rtnl_unlock();
749}
750
751static void tun_detach_all(struct net_device *dev)
752{
753 struct tun_struct *tun = netdev_priv(dev);
754 struct tun_file *tfile, *tmp;
755 int i, n = tun->numqueues;
756
757 for (i = 0; i < n; i++) {
758 tfile = rtnl_dereference(tun->tfiles[i]);
759 BUG_ON(!tfile);
760 tun_napi_disable(tun, tfile);
761 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
762 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
763 RCU_INIT_POINTER(tfile->tun, NULL);
764 --tun->numqueues;
765 }
766 list_for_each_entry(tfile, &tun->disabled, next) {
767 tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
768 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
769 RCU_INIT_POINTER(tfile->tun, NULL);
770 }
771 BUG_ON(tun->numqueues != 0);
772
773 synchronize_net();
774 for (i = 0; i < n; i++) {
775 tfile = rtnl_dereference(tun->tfiles[i]);
776 tun_napi_del(tun, tfile);
777 /* Drop read queue */
778 tun_queue_purge(tfile);
779 xdp_rxq_info_unreg(&tfile->xdp_rxq);
780 sock_put(&tfile->sk);
781 }
782 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
783 tun_enable_queue(tfile);
784 tun_queue_purge(tfile);
785 xdp_rxq_info_unreg(&tfile->xdp_rxq);
786 sock_put(&tfile->sk);
787 }
788 BUG_ON(tun->numdisabled != 0);
789
790 if (tun->flags & IFF_PERSIST)
791 module_put(THIS_MODULE);
792}
793
794static int tun_attach(struct tun_struct *tun, struct file *file,
795 bool skip_filter, bool napi)
796{
797 struct tun_file *tfile = file->private_data;
798 struct net_device *dev = tun->dev;
799 int err;
800
801 err = security_tun_dev_attach(tfile->socket.sk, tun->security);
802 if (err < 0)
803 goto out;
804
805 err = -EINVAL;
806 if (rtnl_dereference(tfile->tun) && !tfile->detached)
807 goto out;
808
809 err = -EBUSY;
810 if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
811 goto out;
812
813 err = -E2BIG;
814 if (!tfile->detached &&
815 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
816 goto out;
817
818 err = 0;
819
820 /* Re-attach the filter to persist device */
821 if (!skip_filter && (tun->filter_attached == true)) {
822 lock_sock(tfile->socket.sk);
823 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
824 release_sock(tfile->socket.sk);
825 if (!err)
826 goto out;
827 }
828
829 if (!tfile->detached &&
830 ptr_ring_resize(&tfile->tx_ring, dev->tx_queue_len,
831 GFP_KERNEL, tun_ptr_free)) {
832 err = -ENOMEM;
833 goto out;
834 }
835
836 tfile->queue_index = tun->numqueues;
837 tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
838
839 if (tfile->detached) {
840 /* Re-attach detached tfile, updating XDP queue_index */
841 WARN_ON(!xdp_rxq_info_is_reg(&tfile->xdp_rxq));
842
843 if (tfile->xdp_rxq.queue_index != tfile->queue_index)
844 tfile->xdp_rxq.queue_index = tfile->queue_index;
845 } else {
846 /* Setup XDP RX-queue info, for new tfile getting attached */
847 err = xdp_rxq_info_reg(&tfile->xdp_rxq,
848 tun->dev, tfile->queue_index);
849 if (err < 0)
850 goto out;
851 err = 0;
852 }
853
854 rcu_assign_pointer(tfile->tun, tun);
855 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
856 tun->numqueues++;
857
858 if (tfile->detached) {
859 tun_enable_queue(tfile);
860 } else {
861 sock_hold(&tfile->sk);
862 tun_napi_init(tun, tfile, napi);
863 }
864
865 tun_set_real_num_queues(tun);
866
867 /* device is allowed to go away first, so no need to hold extra
868 * refcnt.
869 */
870
871out:
872 return err;
873}
874
875static struct tun_struct *tun_get(struct tun_file *tfile)
876{
877 struct tun_struct *tun;
878
879 rcu_read_lock();
880 tun = rcu_dereference(tfile->tun);
881 if (tun)
882 dev_hold(tun->dev);
883 rcu_read_unlock();
884
885 return tun;
886}
887
888static void tun_put(struct tun_struct *tun)
889{
890 dev_put(tun->dev);
891}
892
893/* TAP filtering */
894static void addr_hash_set(u32 *mask, const u8 *addr)
895{
896 int n = ether_crc(ETH_ALEN, addr) >> 26;
897 mask[n >> 5] |= (1 << (n & 31));
898}
899
900static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
901{
902 int n = ether_crc(ETH_ALEN, addr) >> 26;
903 return mask[n >> 5] & (1 << (n & 31));
904}
905
906static int update_filter(struct tap_filter *filter, void __user *arg)
907{
908 struct { u8 u[ETH_ALEN]; } *addr;
909 struct tun_filter uf;
910 int err, alen, n, nexact;
911
912 if (copy_from_user(&uf, arg, sizeof(uf)))
913 return -EFAULT;
914
915 if (!uf.count) {
916 /* Disabled */
917 filter->count = 0;
918 return 0;
919 }
920
921 alen = ETH_ALEN * uf.count;
922 addr = memdup_user(arg + sizeof(uf), alen);
923 if (IS_ERR(addr))
924 return PTR_ERR(addr);
925
926 /* The filter is updated without holding any locks. Which is
927 * perfectly safe. We disable it first and in the worst
928 * case we'll accept a few undesired packets. */
929 filter->count = 0;
930 wmb();
931
932 /* Use first set of addresses as an exact filter */
933 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
934 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
935
936 nexact = n;
937
938 /* Remaining multicast addresses are hashed,
939 * unicast will leave the filter disabled. */
940 memset(filter->mask, 0, sizeof(filter->mask));
941 for (; n < uf.count; n++) {
942 if (!is_multicast_ether_addr(addr[n].u)) {
943 err = 0; /* no filter */
944 goto free_addr;
945 }
946 addr_hash_set(filter->mask, addr[n].u);
947 }
948
949 /* For ALLMULTI just set the mask to all ones.
950 * This overrides the mask populated above. */
951 if ((uf.flags & TUN_FLT_ALLMULTI))
952 memset(filter->mask, ~0, sizeof(filter->mask));
953
954 /* Now enable the filter */
955 wmb();
956 filter->count = nexact;
957
958 /* Return the number of exact filters */
959 err = nexact;
960free_addr:
961 kfree(addr);
962 return err;
963}
964
965/* Returns: 0 - drop, !=0 - accept */
966static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
967{
968 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
969 * at this point. */
970 struct ethhdr *eh = (struct ethhdr *) skb->data;
971 int i;
972
973 /* Exact match */
974 for (i = 0; i < filter->count; i++)
975 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
976 return 1;
977
978 /* Inexact match (multicast only) */
979 if (is_multicast_ether_addr(eh->h_dest))
980 return addr_hash_test(filter->mask, eh->h_dest);
981
982 return 0;
983}
984
985/*
986 * Checks whether the packet is accepted or not.
987 * Returns: 0 - drop, !=0 - accept
988 */
989static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
990{
991 if (!filter->count)
992 return 1;
993
994 return run_filter(filter, skb);
995}
996
997/* Network device part of the driver */
998
999static const struct ethtool_ops tun_ethtool_ops;
1000
1001/* Net device detach from fd. */
1002static void tun_net_uninit(struct net_device *dev)
1003{
1004 tun_detach_all(dev);
1005}
1006
1007/* Net device open. */
1008static int tun_net_open(struct net_device *dev)
1009{
1010 struct tun_struct *tun = netdev_priv(dev);
1011 int i;
1012
1013 netif_tx_start_all_queues(dev);
1014
1015 for (i = 0; i < tun->numqueues; i++) {
1016 struct tun_file *tfile;
1017
1018 tfile = rtnl_dereference(tun->tfiles[i]);
1019 tfile->socket.sk->sk_write_space(tfile->socket.sk);
1020 }
1021
1022 return 0;
1023}
1024
1025/* Net device close. */
1026static int tun_net_close(struct net_device *dev)
1027{
1028 netif_tx_stop_all_queues(dev);
1029 return 0;
1030}
1031
1032/* Net device start xmit */
1033static void tun_automq_xmit(struct tun_struct *tun, struct sk_buff *skb)
1034{
1035#ifdef CONFIG_RPS
1036 if (tun->numqueues == 1 && static_key_false(&rps_needed)) {
1037 /* Select queue was not called for the skbuff, so we extract the
1038 * RPS hash and save it into the flow_table here.
1039 */
1040 __u32 rxhash;
1041
1042 rxhash = __skb_get_hash_symmetric(skb);
1043 if (rxhash) {
1044 struct tun_flow_entry *e;
1045 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)],
1046 rxhash);
1047 if (e)
1048 tun_flow_save_rps_rxhash(e, rxhash);
1049 }
1050 }
1051#endif
1052}
1053
1054static unsigned int run_ebpf_filter(struct tun_struct *tun,
1055 struct sk_buff *skb,
1056 int len)
1057{
1058 struct tun_prog *prog = rcu_dereference(tun->filter_prog);
1059
1060 if (prog)
1061 len = bpf_prog_run_clear_cb(prog->prog, skb);
1062
1063 return len;
1064}
1065
1066/* Net device start xmit */
1067static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
1068{
1069 struct tun_struct *tun = netdev_priv(dev);
1070 int txq = skb->queue_mapping;
1071 struct tun_file *tfile;
1072 int len = skb->len;
1073
1074 rcu_read_lock();
1075 tfile = rcu_dereference(tun->tfiles[txq]);
1076
1077 /* Drop packet if interface is not attached */
1078 if (txq >= tun->numqueues)
1079 goto drop;
1080
1081 if (!rcu_dereference(tun->steering_prog))
1082 tun_automq_xmit(tun, skb);
1083
1084 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
1085
1086 BUG_ON(!tfile);
1087
1088 /* Drop if the filter does not like it.
1089 * This is a noop if the filter is disabled.
1090 * Filter can be enabled only for the TAP devices. */
1091 if (!check_filter(&tun->txflt, skb))
1092 goto drop;
1093
1094 if (tfile->socket.sk->sk_filter &&
1095 sk_filter(tfile->socket.sk, skb))
1096 goto drop;
1097
1098 len = run_ebpf_filter(tun, skb, len);
1099 if (len == 0 || pskb_trim(skb, len))
1100 goto drop;
1101
1102 if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC)))
1103 goto drop;
1104
1105 skb_tx_timestamp(skb);
1106
1107 /* Orphan the skb - required as we might hang on to it
1108 * for indefinite time.
1109 */
1110 skb_orphan(skb);
1111
1112 nf_reset(skb);
1113
1114 if (ptr_ring_produce(&tfile->tx_ring, skb))
1115 goto drop;
1116
1117 /* Notify and wake up reader process */
1118 if (tfile->flags & TUN_FASYNC)
1119 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1120 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1121
1122 rcu_read_unlock();
1123 return NETDEV_TX_OK;
1124
1125drop:
1126 this_cpu_inc(tun->pcpu_stats->tx_dropped);
1127 skb_tx_error(skb);
1128 kfree_skb(skb);
1129 rcu_read_unlock();
1130 return NET_XMIT_DROP;
1131}
1132
1133static void tun_net_mclist(struct net_device *dev)
1134{
1135 /*
1136 * This callback is supposed to deal with mc filter in
1137 * _rx_ path and has nothing to do with the _tx_ path.
1138 * In rx path we always accept everything userspace gives us.
1139 */
1140}
1141
1142static netdev_features_t tun_net_fix_features(struct net_device *dev,
1143 netdev_features_t features)
1144{
1145 struct tun_struct *tun = netdev_priv(dev);
1146
1147 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
1148}
1149#ifdef CONFIG_NET_POLL_CONTROLLER
1150static void tun_poll_controller(struct net_device *dev)
1151{
1152 /*
1153 * Tun only receives frames when:
1154 * 1) the char device endpoint gets data from user space
1155 * 2) the tun socket gets a sendmsg call from user space
1156 * If NAPI is not enabled, since both of those are synchronous
1157 * operations, we are guaranteed never to have pending data when we poll
1158 * for it so there is nothing to do here but return.
1159 * We need this though so netpoll recognizes us as an interface that
1160 * supports polling, which enables bridge devices in virt setups to
1161 * still use netconsole
1162 * If NAPI is enabled, however, we need to schedule polling for all
1163 * queues unless we are using napi_gro_frags(), which we call in
1164 * process context and not in NAPI context.
1165 */
1166 struct tun_struct *tun = netdev_priv(dev);
1167
1168 if (tun->flags & IFF_NAPI) {
1169 struct tun_file *tfile;
1170 int i;
1171
1172 if (tun_napi_frags_enabled(tun))
1173 return;
1174
1175 rcu_read_lock();
1176 for (i = 0; i < tun->numqueues; i++) {
1177 tfile = rcu_dereference(tun->tfiles[i]);
1178 if (tfile->napi_enabled)
1179 napi_schedule(&tfile->napi);
1180 }
1181 rcu_read_unlock();
1182 }
1183 return;
1184}
1185#endif
1186
1187static void tun_set_headroom(struct net_device *dev, int new_hr)
1188{
1189 struct tun_struct *tun = netdev_priv(dev);
1190
1191 if (new_hr < NET_SKB_PAD)
1192 new_hr = NET_SKB_PAD;
1193
1194 tun->align = new_hr;
1195}
1196
1197static void
1198tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
1199{
1200 u32 rx_dropped = 0, tx_dropped = 0, rx_frame_errors = 0;
1201 struct tun_struct *tun = netdev_priv(dev);
1202 struct tun_pcpu_stats *p;
1203 int i;
1204
1205 for_each_possible_cpu(i) {
1206 u64 rxpackets, rxbytes, txpackets, txbytes;
1207 unsigned int start;
1208
1209 p = per_cpu_ptr(tun->pcpu_stats, i);
1210 do {
1211 start = u64_stats_fetch_begin(&p->syncp);
1212 rxpackets = p->rx_packets;
1213 rxbytes = p->rx_bytes;
1214 txpackets = p->tx_packets;
1215 txbytes = p->tx_bytes;
1216 } while (u64_stats_fetch_retry(&p->syncp, start));
1217
1218 stats->rx_packets += rxpackets;
1219 stats->rx_bytes += rxbytes;
1220 stats->tx_packets += txpackets;
1221 stats->tx_bytes += txbytes;
1222
1223 /* u32 counters */
1224 rx_dropped += p->rx_dropped;
1225 rx_frame_errors += p->rx_frame_errors;
1226 tx_dropped += p->tx_dropped;
1227 }
1228 stats->rx_dropped = rx_dropped;
1229 stats->rx_frame_errors = rx_frame_errors;
1230 stats->tx_dropped = tx_dropped;
1231}
1232
1233static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1234 struct netlink_ext_ack *extack)
1235{
1236 struct tun_struct *tun = netdev_priv(dev);
1237 struct bpf_prog *old_prog;
1238
1239 old_prog = rtnl_dereference(tun->xdp_prog);
1240 rcu_assign_pointer(tun->xdp_prog, prog);
1241 if (old_prog)
1242 bpf_prog_put(old_prog);
1243
1244 return 0;
1245}
1246
1247static u32 tun_xdp_query(struct net_device *dev)
1248{
1249 struct tun_struct *tun = netdev_priv(dev);
1250 const struct bpf_prog *xdp_prog;
1251
1252 xdp_prog = rtnl_dereference(tun->xdp_prog);
1253 if (xdp_prog)
1254 return xdp_prog->aux->id;
1255
1256 return 0;
1257}
1258
1259static int tun_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1260{
1261 switch (xdp->command) {
1262 case XDP_SETUP_PROG:
1263 return tun_xdp_set(dev, xdp->prog, xdp->extack);
1264 case XDP_QUERY_PROG:
1265 xdp->prog_id = tun_xdp_query(dev);
1266 xdp->prog_attached = !!xdp->prog_id;
1267 return 0;
1268 default:
1269 return -EINVAL;
1270 }
1271}
1272
1273static const struct net_device_ops tun_netdev_ops = {
1274 .ndo_uninit = tun_net_uninit,
1275 .ndo_open = tun_net_open,
1276 .ndo_stop = tun_net_close,
1277 .ndo_start_xmit = tun_net_xmit,
1278 .ndo_fix_features = tun_net_fix_features,
1279 .ndo_select_queue = tun_select_queue,
1280#ifdef CONFIG_NET_POLL_CONTROLLER
1281 .ndo_poll_controller = tun_poll_controller,
1282#endif
1283 .ndo_set_rx_headroom = tun_set_headroom,
1284 .ndo_get_stats64 = tun_net_get_stats64,
1285};
1286
1287static int tun_xdp_xmit(struct net_device *dev, struct xdp_buff *xdp)
1288{
1289 struct tun_struct *tun = netdev_priv(dev);
1290 struct xdp_buff *buff = xdp->data_hard_start;
1291 int headroom = xdp->data - xdp->data_hard_start;
1292 struct tun_file *tfile;
1293 u32 numqueues;
1294 int ret = 0;
1295
1296 /* Assure headroom is available and buff is properly aligned */
1297 if (unlikely(headroom < sizeof(*xdp) || tun_is_xdp_buff(xdp)))
1298 return -ENOSPC;
1299
1300 *buff = *xdp;
1301
1302 rcu_read_lock();
1303
1304 numqueues = READ_ONCE(tun->numqueues);
1305 if (!numqueues) {
1306 ret = -ENOSPC;
1307 goto out;
1308 }
1309
1310 tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
1311 numqueues]);
1312 /* Encode the XDP flag into lowest bit for consumer to differ
1313 * XDP buffer from sk_buff.
1314 */
1315 if (ptr_ring_produce(&tfile->tx_ring, tun_xdp_to_ptr(buff))) {
1316 this_cpu_inc(tun->pcpu_stats->tx_dropped);
1317 ret = -ENOSPC;
1318 }
1319
1320out:
1321 rcu_read_unlock();
1322 return ret;
1323}
1324
1325static void tun_xdp_flush(struct net_device *dev)
1326{
1327 struct tun_struct *tun = netdev_priv(dev);
1328 struct tun_file *tfile;
1329 u32 numqueues;
1330
1331 rcu_read_lock();
1332
1333 numqueues = READ_ONCE(tun->numqueues);
1334 if (!numqueues)
1335 goto out;
1336
1337 tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
1338 numqueues]);
1339 /* Notify and wake up reader process */
1340 if (tfile->flags & TUN_FASYNC)
1341 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
1342 tfile->socket.sk->sk_data_ready(tfile->socket.sk);
1343
1344out:
1345 rcu_read_unlock();
1346}
1347
1348static const struct net_device_ops tap_netdev_ops = {
1349 .ndo_uninit = tun_net_uninit,
1350 .ndo_open = tun_net_open,
1351 .ndo_stop = tun_net_close,
1352 .ndo_start_xmit = tun_net_xmit,
1353 .ndo_fix_features = tun_net_fix_features,
1354 .ndo_set_rx_mode = tun_net_mclist,
1355 .ndo_set_mac_address = eth_mac_addr,
1356 .ndo_validate_addr = eth_validate_addr,
1357 .ndo_select_queue = tun_select_queue,
1358#ifdef CONFIG_NET_POLL_CONTROLLER
1359 .ndo_poll_controller = tun_poll_controller,
1360#endif
1361 .ndo_features_check = passthru_features_check,
1362 .ndo_set_rx_headroom = tun_set_headroom,
1363 .ndo_get_stats64 = tun_net_get_stats64,
1364 .ndo_bpf = tun_xdp,
1365 .ndo_xdp_xmit = tun_xdp_xmit,
1366 .ndo_xdp_flush = tun_xdp_flush,
1367};
1368
1369static void tun_flow_init(struct tun_struct *tun)
1370{
1371 int i;
1372
1373 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
1374 INIT_HLIST_HEAD(&tun->flows[i]);
1375
1376 tun->ageing_time = TUN_FLOW_EXPIRE;
1377 timer_setup(&tun->flow_gc_timer, tun_flow_cleanup, 0);
1378 mod_timer(&tun->flow_gc_timer,
1379 round_jiffies_up(jiffies + tun->ageing_time));
1380}
1381
1382static void tun_flow_uninit(struct tun_struct *tun)
1383{
1384 del_timer_sync(&tun->flow_gc_timer);
1385 tun_flow_flush(tun);
1386}
1387
1388#define MIN_MTU 68
1389#define MAX_MTU 65535
1390
1391/* Initialize net device. */
1392static void tun_net_init(struct net_device *dev)
1393{
1394 struct tun_struct *tun = netdev_priv(dev);
1395
1396 switch (tun->flags & TUN_TYPE_MASK) {
1397 case IFF_TUN:
1398 dev->netdev_ops = &tun_netdev_ops;
1399
1400 /* Point-to-Point TUN Device */
1401 dev->hard_header_len = 0;
1402 dev->addr_len = 0;
1403 dev->mtu = 1500;
1404
1405 /* Zero header length */
1406 dev->type = ARPHRD_NONE;
1407 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1408 break;
1409
1410 case IFF_TAP:
1411 dev->netdev_ops = &tap_netdev_ops;
1412 /* Ethernet TAP Device */
1413 ether_setup(dev);
1414 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1415 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1416
1417 eth_hw_addr_random(dev);
1418
1419 break;
1420 }
1421
1422 dev->min_mtu = MIN_MTU;
1423 dev->max_mtu = MAX_MTU - dev->hard_header_len;
1424}
1425
1426static bool tun_sock_writeable(struct tun_struct *tun, struct tun_file *tfile)
1427{
1428 struct sock *sk = tfile->socket.sk;
1429
1430 return (tun->dev->flags & IFF_UP) && sock_writeable(sk);
1431}
1432
1433/* Character device part */
1434
1435/* Poll */
1436static __poll_t tun_chr_poll(struct file *file, poll_table *wait)
1437{
1438 struct tun_file *tfile = file->private_data;
1439 struct tun_struct *tun = tun_get(tfile);
1440 struct sock *sk;
1441 __poll_t mask = 0;
1442
1443 if (!tun)
1444 return EPOLLERR;
1445
1446 sk = tfile->socket.sk;
1447
1448 tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
1449
1450 poll_wait(file, sk_sleep(sk), wait);
1451
1452 if (!ptr_ring_empty(&tfile->tx_ring))
1453 mask |= EPOLLIN | EPOLLRDNORM;
1454
1455 /* Make sure SOCKWQ_ASYNC_NOSPACE is set if not writable to
1456 * guarantee EPOLLOUT to be raised by either here or
1457 * tun_sock_write_space(). Then process could get notification
1458 * after it writes to a down device and meets -EIO.
1459 */
1460 if (tun_sock_writeable(tun, tfile) ||
1461 (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
1462 tun_sock_writeable(tun, tfile)))
1463 mask |= EPOLLOUT | EPOLLWRNORM;
1464
1465 if (tun->dev->reg_state != NETREG_REGISTERED)
1466 mask = EPOLLERR;
1467
1468 tun_put(tun);
1469 return mask;
1470}
1471
1472static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile,
1473 size_t len,
1474 const struct iov_iter *it)
1475{
1476 struct sk_buff *skb;
1477 size_t linear;
1478 int err;
1479 int i;
1480
1481 if (it->nr_segs > MAX_SKB_FRAGS + 1)
1482 return ERR_PTR(-ENOMEM);
1483
1484 local_bh_disable();
1485 skb = napi_get_frags(&tfile->napi);
1486 local_bh_enable();
1487 if (!skb)
1488 return ERR_PTR(-ENOMEM);
1489
1490 linear = iov_iter_single_seg_count(it);
1491 err = __skb_grow(skb, linear);
1492 if (err)
1493 goto free;
1494
1495 skb->len = len;
1496 skb->data_len = len - linear;
1497 skb->truesize += skb->data_len;
1498
1499 for (i = 1; i < it->nr_segs; i++) {
1500 struct page_frag *pfrag = ¤t->task_frag;
1501 size_t fragsz = it->iov[i].iov_len;
1502
1503 if (fragsz == 0 || fragsz > PAGE_SIZE) {
1504 err = -EINVAL;
1505 goto free;
1506 }
1507
1508 if (!skb_page_frag_refill(fragsz, pfrag, GFP_KERNEL)) {
1509 err = -ENOMEM;
1510 goto free;
1511 }
1512
1513 skb_fill_page_desc(skb, i - 1, pfrag->page,
1514 pfrag->offset, fragsz);
1515 page_ref_inc(pfrag->page);
1516 pfrag->offset += fragsz;
1517 }
1518
1519 return skb;
1520free:
1521 /* frees skb and all frags allocated with napi_alloc_frag() */
1522 napi_free_frags(&tfile->napi);
1523 return ERR_PTR(err);
1524}
1525
1526/* prepad is the amount to reserve at front. len is length after that.
1527 * linear is a hint as to how much to copy (usually headers). */
1528static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
1529 size_t prepad, size_t len,
1530 size_t linear, int noblock)
1531{
1532 struct sock *sk = tfile->socket.sk;
1533 struct sk_buff *skb;
1534 int err;
1535
1536 /* Under a page? Don't bother with paged skb. */
1537 if (prepad + len < PAGE_SIZE || !linear)
1538 linear = len;
1539
1540 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1541 &err, 0);
1542 if (!skb)
1543 return ERR_PTR(err);
1544
1545 skb_reserve(skb, prepad);
1546 skb_put(skb, linear);
1547 skb->data_len = len - linear;
1548 skb->len += len - linear;
1549
1550 return skb;
1551}
1552
1553static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile,
1554 struct sk_buff *skb, int more)
1555{
1556 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1557 struct sk_buff_head process_queue;
1558 u32 rx_batched = tun->rx_batched;
1559 bool rcv = false;
1560
1561 if (!rx_batched || (!more && skb_queue_empty(queue))) {
1562 local_bh_disable();
1563 netif_receive_skb(skb);
1564 local_bh_enable();
1565 return;
1566 }
1567
1568 spin_lock(&queue->lock);
1569 if (!more || skb_queue_len(queue) == rx_batched) {
1570 __skb_queue_head_init(&process_queue);
1571 skb_queue_splice_tail_init(queue, &process_queue);
1572 rcv = true;
1573 } else {
1574 __skb_queue_tail(queue, skb);
1575 }
1576 spin_unlock(&queue->lock);
1577
1578 if (rcv) {
1579 struct sk_buff *nskb;
1580
1581 local_bh_disable();
1582 while ((nskb = __skb_dequeue(&process_queue)))
1583 netif_receive_skb(nskb);
1584 netif_receive_skb(skb);
1585 local_bh_enable();
1586 }
1587}
1588
1589static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile,
1590 int len, int noblock, bool zerocopy)
1591{
1592 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
1593 return false;
1594
1595 if (tfile->socket.sk->sk_sndbuf != INT_MAX)
1596 return false;
1597
1598 if (!noblock)
1599 return false;
1600
1601 if (zerocopy)
1602 return false;
1603
1604 if (SKB_DATA_ALIGN(len + TUN_RX_PAD) +
1605 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
1606 return false;
1607
1608 return true;
1609}
1610
1611static struct sk_buff *tun_build_skb(struct tun_struct *tun,
1612 struct tun_file *tfile,
1613 struct iov_iter *from,
1614 struct virtio_net_hdr *hdr,
1615 int len, int *skb_xdp)
1616{
1617 struct page_frag *alloc_frag = ¤t->task_frag;
1618 struct sk_buff *skb;
1619 struct bpf_prog *xdp_prog;
1620 int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1621 unsigned int delta = 0;
1622 char *buf;
1623 size_t copied;
1624 int err, pad = TUN_RX_PAD;
1625
1626 rcu_read_lock();
1627 xdp_prog = rcu_dereference(tun->xdp_prog);
1628 if (xdp_prog)
1629 pad += TUN_HEADROOM;
1630 buflen += SKB_DATA_ALIGN(len + pad);
1631 rcu_read_unlock();
1632
1633 alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES);
1634 if (unlikely(!skb_page_frag_refill(buflen, alloc_frag, GFP_KERNEL)))
1635 return ERR_PTR(-ENOMEM);
1636
1637 buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
1638 copied = copy_page_from_iter(alloc_frag->page,
1639 alloc_frag->offset + pad,
1640 len, from);
1641 if (copied != len)
1642 return ERR_PTR(-EFAULT);
1643
1644 /* There's a small window that XDP may be set after the check
1645 * of xdp_prog above, this should be rare and for simplicity
1646 * we do XDP on skb in case the headroom is not enough.
1647 */
1648 if (hdr->gso_type || !xdp_prog)
1649 *skb_xdp = 1;
1650 else
1651 *skb_xdp = 0;
1652
1653 local_bh_disable();
1654 rcu_read_lock();
1655 xdp_prog = rcu_dereference(tun->xdp_prog);
1656 if (xdp_prog && !*skb_xdp) {
1657 struct xdp_buff xdp;
1658 void *orig_data;
1659 u32 act;
1660
1661 xdp.data_hard_start = buf;
1662 xdp.data = buf + pad;
1663 xdp_set_data_meta_invalid(&xdp);
1664 xdp.data_end = xdp.data + len;
1665 xdp.rxq = &tfile->xdp_rxq;
1666 orig_data = xdp.data;
1667 act = bpf_prog_run_xdp(xdp_prog, &xdp);
1668
1669 switch (act) {
1670 case XDP_REDIRECT:
1671 get_page(alloc_frag->page);
1672 alloc_frag->offset += buflen;
1673 err = xdp_do_redirect(tun->dev, &xdp, xdp_prog);
1674 xdp_do_flush_map();
1675 if (err)
1676 goto err_redirect;
1677 rcu_read_unlock();
1678 local_bh_enable();
1679 return NULL;
1680 case XDP_TX:
1681 get_page(alloc_frag->page);
1682 alloc_frag->offset += buflen;
1683 if (tun_xdp_xmit(tun->dev, &xdp))
1684 goto err_redirect;
1685 tun_xdp_flush(tun->dev);
1686 rcu_read_unlock();
1687 local_bh_enable();
1688 return NULL;
1689 case XDP_PASS:
1690 delta = orig_data - xdp.data;
1691 break;
1692 default:
1693 bpf_warn_invalid_xdp_action(act);
1694 /* fall through */
1695 case XDP_ABORTED:
1696 trace_xdp_exception(tun->dev, xdp_prog, act);
1697 /* fall through */
1698 case XDP_DROP:
1699 goto err_xdp;
1700 }
1701 }
1702
1703 skb = build_skb(buf, buflen);
1704 if (!skb) {
1705 rcu_read_unlock();
1706 local_bh_enable();
1707 return ERR_PTR(-ENOMEM);
1708 }
1709
1710 skb_reserve(skb, pad - delta);
1711 skb_put(skb, len + delta);
1712 get_page(alloc_frag->page);
1713 alloc_frag->offset += buflen;
1714
1715 rcu_read_unlock();
1716 local_bh_enable();
1717
1718 return skb;
1719
1720err_redirect:
1721 put_page(alloc_frag->page);
1722err_xdp:
1723 rcu_read_unlock();
1724 local_bh_enable();
1725 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1726 return NULL;
1727}
1728
1729/* Get packet from user space buffer */
1730static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1731 void *msg_control, struct iov_iter *from,
1732 int noblock, bool more)
1733{
1734 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1735 struct sk_buff *skb;
1736 size_t total_len = iov_iter_count(from);
1737 size_t len = total_len, align = tun->align, linear;
1738 struct virtio_net_hdr gso = { 0 };
1739 struct tun_pcpu_stats *stats;
1740 int good_linear;
1741 int copylen;
1742 bool zerocopy = false;
1743 int err;
1744 u32 rxhash = 0;
1745 int skb_xdp = 1;
1746 bool frags = tun_napi_frags_enabled(tun);
1747
1748 if (!(tun->dev->flags & IFF_UP))
1749 return -EIO;
1750
1751 if (!(tun->flags & IFF_NO_PI)) {
1752 if (len < sizeof(pi))
1753 return -EINVAL;
1754 len -= sizeof(pi);
1755
1756 if (!copy_from_iter_full(&pi, sizeof(pi), from))
1757 return -EFAULT;
1758 }
1759
1760 if (tun->flags & IFF_VNET_HDR) {
1761 int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
1762
1763 if (len < vnet_hdr_sz)
1764 return -EINVAL;
1765 len -= vnet_hdr_sz;
1766
1767 if (!copy_from_iter_full(&gso, sizeof(gso), from))
1768 return -EFAULT;
1769
1770 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1771 tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
1772 gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
1773
1774 if (tun16_to_cpu(tun, gso.hdr_len) > len)
1775 return -EINVAL;
1776 iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
1777 }
1778
1779 if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
1780 align += NET_IP_ALIGN;
1781 if (unlikely(len < ETH_HLEN ||
1782 (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
1783 return -EINVAL;
1784 }
1785
1786 good_linear = SKB_MAX_HEAD(align);
1787
1788 if (msg_control) {
1789 struct iov_iter i = *from;
1790
1791 /* There are 256 bytes to be copied in skb, so there is
1792 * enough room for skb expand head in case it is used.
1793 * The rest of the buffer is mapped from userspace.
1794 */
1795 copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
1796 if (copylen > good_linear)
1797 copylen = good_linear;
1798 linear = copylen;
1799 iov_iter_advance(&i, copylen);
1800 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
1801 zerocopy = true;
1802 }
1803
1804 if (!frags && tun_can_build_skb(tun, tfile, len, noblock, zerocopy)) {
1805 /* For the packet that is not easy to be processed
1806 * (e.g gso or jumbo packet), we will do it at after
1807 * skb was created with generic XDP routine.
1808 */
1809 skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp);
1810 if (IS_ERR(skb)) {
1811 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1812 return PTR_ERR(skb);
1813 }
1814 if (!skb)
1815 return total_len;
1816 } else {
1817 if (!zerocopy) {
1818 copylen = len;
1819 if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
1820 linear = good_linear;
1821 else
1822 linear = tun16_to_cpu(tun, gso.hdr_len);
1823 }
1824
1825 if (frags) {
1826 mutex_lock(&tfile->napi_mutex);
1827 skb = tun_napi_alloc_frags(tfile, copylen, from);
1828 /* tun_napi_alloc_frags() enforces a layout for the skb.
1829 * If zerocopy is enabled, then this layout will be
1830 * overwritten by zerocopy_sg_from_iter().
1831 */
1832 zerocopy = false;
1833 } else {
1834 skb = tun_alloc_skb(tfile, align, copylen, linear,
1835 noblock);
1836 }
1837
1838 if (IS_ERR(skb)) {
1839 if (PTR_ERR(skb) != -EAGAIN)
1840 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1841 if (frags)
1842 mutex_unlock(&tfile->napi_mutex);
1843 return PTR_ERR(skb);
1844 }
1845
1846 if (zerocopy)
1847 err = zerocopy_sg_from_iter(skb, from);
1848 else
1849 err = skb_copy_datagram_from_iter(skb, 0, from, len);
1850
1851 if (err) {
1852 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1853 kfree_skb(skb);
1854 if (frags) {
1855 tfile->napi.skb = NULL;
1856 mutex_unlock(&tfile->napi_mutex);
1857 }
1858
1859 return -EFAULT;
1860 }
1861 }
1862
1863 if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
1864 this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
1865 kfree_skb(skb);
1866 if (frags) {
1867 tfile->napi.skb = NULL;
1868 mutex_unlock(&tfile->napi_mutex);
1869 }
1870
1871 return -EINVAL;
1872 }
1873
1874 switch (tun->flags & TUN_TYPE_MASK) {
1875 case IFF_TUN:
1876 if (tun->flags & IFF_NO_PI) {
1877 u8 ip_version = skb->len ? (skb->data[0] >> 4) : 0;
1878
1879 switch (ip_version) {
1880 case 4:
1881 pi.proto = htons(ETH_P_IP);
1882 break;
1883 case 6:
1884 pi.proto = htons(ETH_P_IPV6);
1885 break;
1886 default:
1887 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1888 kfree_skb(skb);
1889 return -EINVAL;
1890 }
1891 }
1892
1893 skb_reset_mac_header(skb);
1894 skb->protocol = pi.proto;
1895 skb->dev = tun->dev;
1896 break;
1897 case IFF_TAP:
1898 if (!frags)
1899 skb->protocol = eth_type_trans(skb, tun->dev);
1900 break;
1901 }
1902
1903 /* copy skb_ubuf_info for callback when skb has no error */
1904 if (zerocopy) {
1905 skb_shinfo(skb)->destructor_arg = msg_control;
1906 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1907 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1908 } else if (msg_control) {
1909 struct ubuf_info *uarg = msg_control;
1910 uarg->callback(uarg, false);
1911 }
1912
1913 skb_reset_network_header(skb);
1914 skb_probe_transport_header(skb, 0);
1915
1916 if (skb_xdp) {
1917 struct bpf_prog *xdp_prog;
1918 int ret;
1919
1920 local_bh_disable();
1921 rcu_read_lock();
1922 xdp_prog = rcu_dereference(tun->xdp_prog);
1923 if (xdp_prog) {
1924 ret = do_xdp_generic(xdp_prog, skb);
1925 if (ret != XDP_PASS) {
1926 rcu_read_unlock();
1927 local_bh_enable();
1928 return total_len;
1929 }
1930 }
1931 rcu_read_unlock();
1932 local_bh_enable();
1933 }
1934
1935 rcu_read_lock();
1936 if (!rcu_dereference(tun->steering_prog))
1937 rxhash = __skb_get_hash_symmetric(skb);
1938 rcu_read_unlock();
1939
1940 if (frags) {
1941 /* Exercise flow dissector code path. */
1942 u32 headlen = eth_get_headlen(skb->data, skb_headlen(skb));
1943
1944 if (unlikely(headlen > skb_headlen(skb))) {
1945 this_cpu_inc(tun->pcpu_stats->rx_dropped);
1946 napi_free_frags(&tfile->napi);
1947 mutex_unlock(&tfile->napi_mutex);
1948 WARN_ON(1);
1949 return -ENOMEM;
1950 }
1951
1952 local_bh_disable();
1953 napi_gro_frags(&tfile->napi);
1954 local_bh_enable();
1955 mutex_unlock(&tfile->napi_mutex);
1956 } else if (tfile->napi_enabled) {
1957 struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
1958 int queue_len;
1959
1960 spin_lock_bh(&queue->lock);
1961 __skb_queue_tail(queue, skb);
1962 queue_len = skb_queue_len(queue);
1963 spin_unlock(&queue->lock);
1964
1965 if (!more || queue_len > NAPI_POLL_WEIGHT)
1966 napi_schedule(&tfile->napi);
1967
1968 local_bh_enable();
1969 } else if (!IS_ENABLED(CONFIG_4KSTACKS)) {
1970 tun_rx_batched(tun, tfile, skb, more);
1971 } else {
1972 netif_rx_ni(skb);
1973 }
1974
1975 stats = get_cpu_ptr(tun->pcpu_stats);
1976 u64_stats_update_begin(&stats->syncp);
1977 stats->rx_packets++;
1978 stats->rx_bytes += len;
1979 u64_stats_update_end(&stats->syncp);
1980 put_cpu_ptr(stats);
1981
1982 if (rxhash)
1983 tun_flow_update(tun, rxhash, tfile);
1984
1985 return total_len;
1986}
1987
1988static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
1989{
1990 struct file *file = iocb->ki_filp;
1991 struct tun_file *tfile = file->private_data;
1992 struct tun_struct *tun = tun_get(tfile);
1993 ssize_t result;
1994
1995 if (!tun)
1996 return -EBADFD;
1997
1998 result = tun_get_user(tun, tfile, NULL, from,
1999 file->f_flags & O_NONBLOCK, false);
2000
2001 tun_put(tun);
2002 return result;
2003}
2004
2005static ssize_t tun_put_user_xdp(struct tun_struct *tun,
2006 struct tun_file *tfile,
2007 struct xdp_buff *xdp,
2008 struct iov_iter *iter)
2009{
2010 int vnet_hdr_sz = 0;
2011 size_t size = xdp->data_end - xdp->data;
2012 struct tun_pcpu_stats *stats;
2013 size_t ret;
2014
2015 if (tun->flags & IFF_VNET_HDR) {
2016 struct virtio_net_hdr gso = { 0 };
2017
2018 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2019 if (unlikely(iov_iter_count(iter) < vnet_hdr_sz))
2020 return -EINVAL;
2021 if (unlikely(copy_to_iter(&gso, sizeof(gso), iter) !=
2022 sizeof(gso)))
2023 return -EFAULT;
2024 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2025 }
2026
2027 ret = copy_to_iter(xdp->data, size, iter) + vnet_hdr_sz;
2028
2029 stats = get_cpu_ptr(tun->pcpu_stats);
2030 u64_stats_update_begin(&stats->syncp);
2031 stats->tx_packets++;
2032 stats->tx_bytes += ret;
2033 u64_stats_update_end(&stats->syncp);
2034 put_cpu_ptr(tun->pcpu_stats);
2035
2036 return ret;
2037}
2038
2039/* Put packet to the user space buffer */
2040static ssize_t tun_put_user(struct tun_struct *tun,
2041 struct tun_file *tfile,
2042 struct sk_buff *skb,
2043 struct iov_iter *iter)
2044{
2045 struct tun_pi pi = { 0, skb->protocol };
2046 struct tun_pcpu_stats *stats;
2047 ssize_t total;
2048 int vlan_offset = 0;
2049 int vlan_hlen = 0;
2050 int vnet_hdr_sz = 0;
2051
2052 if (skb_vlan_tag_present(skb))
2053 vlan_hlen = VLAN_HLEN;
2054
2055 if (tun->flags & IFF_VNET_HDR)
2056 vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
2057
2058 total = skb->len + vlan_hlen + vnet_hdr_sz;
2059
2060 if (!(tun->flags & IFF_NO_PI)) {
2061 if (iov_iter_count(iter) < sizeof(pi))
2062 return -EINVAL;
2063
2064 total += sizeof(pi);
2065 if (iov_iter_count(iter) < total) {
2066 /* Packet will be striped */
2067 pi.flags |= TUN_PKT_STRIP;
2068 }
2069
2070 if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
2071 return -EFAULT;
2072 }
2073
2074 if (vnet_hdr_sz) {
2075 struct virtio_net_hdr gso;
2076
2077 if (iov_iter_count(iter) < vnet_hdr_sz)
2078 return -EINVAL;
2079
2080 if (virtio_net_hdr_from_skb(skb, &gso,
2081 tun_is_little_endian(tun), true)) {
2082 struct skb_shared_info *sinfo = skb_shinfo(skb);
2083 pr_err("unexpected GSO type: "
2084 "0x%x, gso_size %d, hdr_len %d\n",
2085 sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
2086 tun16_to_cpu(tun, gso.hdr_len));
2087 print_hex_dump(KERN_ERR, "tun: ",
2088 DUMP_PREFIX_NONE,
2089 16, 1, skb->head,
2090 min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
2091 WARN_ON_ONCE(1);
2092 return -EINVAL;
2093 }
2094
2095 if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
2096 return -EFAULT;
2097
2098 iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
2099 }
2100
2101 if (vlan_hlen) {
2102 int ret;
2103 struct veth veth;
2104
2105 veth.h_vlan_proto = skb->vlan_proto;
2106 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
2107
2108 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
2109
2110 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
2111 if (ret || !iov_iter_count(iter))
2112 goto done;
2113
2114 ret = copy_to_iter(&veth, sizeof(veth), iter);
2115 if (ret != sizeof(veth) || !iov_iter_count(iter))
2116 goto done;
2117 }
2118
2119 skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
2120
2121done:
2122 /* caller is in process context, */
2123 stats = get_cpu_ptr(tun->pcpu_stats);
2124 u64_stats_update_begin(&stats->syncp);
2125 stats->tx_packets++;
2126 stats->tx_bytes += skb->len + vlan_hlen;
2127 u64_stats_update_end(&stats->syncp);
2128 put_cpu_ptr(tun->pcpu_stats);
2129
2130 return total;
2131}
2132
2133static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err)
2134{
2135 DECLARE_WAITQUEUE(wait, current);
2136 void *ptr = NULL;
2137 int error = 0;
2138
2139 ptr = ptr_ring_consume(&tfile->tx_ring);
2140 if (ptr)
2141 goto out;
2142 if (noblock) {
2143 error = -EAGAIN;
2144 goto out;
2145 }
2146
2147 add_wait_queue(&tfile->wq.wait, &wait);
2148 current->state = TASK_INTERRUPTIBLE;
2149
2150 while (1) {
2151 ptr = ptr_ring_consume(&tfile->tx_ring);
2152 if (ptr)
2153 break;
2154 if (signal_pending(current)) {
2155 error = -ERESTARTSYS;
2156 break;
2157 }
2158 if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
2159 error = -EFAULT;
2160 break;
2161 }
2162
2163 schedule();
2164 }
2165
2166 current->state = TASK_RUNNING;
2167 remove_wait_queue(&tfile->wq.wait, &wait);
2168
2169out:
2170 *err = error;
2171 return ptr;
2172}
2173
2174static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
2175 struct iov_iter *to,
2176 int noblock, void *ptr)
2177{
2178 ssize_t ret;
2179 int err;
2180
2181 tun_debug(KERN_INFO, tun, "tun_do_read\n");
2182
2183 if (!iov_iter_count(to)) {
2184 tun_ptr_free(ptr);
2185 return 0;
2186 }
2187
2188 if (!ptr) {
2189 /* Read frames from ring */
2190 ptr = tun_ring_recv(tfile, noblock, &err);
2191 if (!ptr)
2192 return err;
2193 }
2194
2195 if (tun_is_xdp_buff(ptr)) {
2196 struct xdp_buff *xdp = tun_ptr_to_xdp(ptr);
2197
2198 ret = tun_put_user_xdp(tun, tfile, xdp, to);
2199 put_page(virt_to_head_page(xdp->data));
2200 } else {
2201 struct sk_buff *skb = ptr;
2202
2203 ret = tun_put_user(tun, tfile, skb, to);
2204 if (unlikely(ret < 0))
2205 kfree_skb(skb);
2206 else
2207 consume_skb(skb);
2208 }
2209
2210 return ret;
2211}
2212
2213static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
2214{
2215 struct file *file = iocb->ki_filp;
2216 struct tun_file *tfile = file->private_data;
2217 struct tun_struct *tun = tun_get(tfile);
2218 ssize_t len = iov_iter_count(to), ret;
2219
2220 if (!tun)
2221 return -EBADFD;
2222 ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK, NULL);
2223 ret = min_t(ssize_t, ret, len);
2224 if (ret > 0)
2225 iocb->ki_pos = ret;
2226 tun_put(tun);
2227 return ret;
2228}
2229
2230static void tun_prog_free(struct rcu_head *rcu)
2231{
2232 struct tun_prog *prog = container_of(rcu, struct tun_prog, rcu);
2233
2234 bpf_prog_destroy(prog->prog);
2235 kfree(prog);
2236}
2237
2238static int __tun_set_ebpf(struct tun_struct *tun,
2239 struct tun_prog __rcu **prog_p,
2240 struct bpf_prog *prog)
2241{
2242 struct tun_prog *old, *new = NULL;
2243
2244 if (prog) {
2245 new = kmalloc(sizeof(*new), GFP_KERNEL);
2246 if (!new)
2247 return -ENOMEM;
2248 new->prog = prog;
2249 }
2250
2251 spin_lock_bh(&tun->lock);
2252 old = rcu_dereference_protected(*prog_p,
2253 lockdep_is_held(&tun->lock));
2254 rcu_assign_pointer(*prog_p, new);
2255 spin_unlock_bh(&tun->lock);
2256
2257 if (old)
2258 call_rcu(&old->rcu, tun_prog_free);
2259
2260 return 0;
2261}
2262
2263static void tun_free_netdev(struct net_device *dev)
2264{
2265 struct tun_struct *tun = netdev_priv(dev);
2266
2267 BUG_ON(!(list_empty(&tun->disabled)));
2268 free_percpu(tun->pcpu_stats);
2269 tun_flow_uninit(tun);
2270 security_tun_dev_free_security(tun->security);
2271 __tun_set_ebpf(tun, &tun->steering_prog, NULL);
2272 __tun_set_ebpf(tun, &tun->filter_prog, NULL);
2273}
2274
2275static void tun_setup(struct net_device *dev)
2276{
2277 struct tun_struct *tun = netdev_priv(dev);
2278
2279 tun->owner = INVALID_UID;
2280 tun->group = INVALID_GID;
2281
2282 dev->ethtool_ops = &tun_ethtool_ops;
2283 dev->needs_free_netdev = true;
2284 dev->priv_destructor = tun_free_netdev;
2285 /* We prefer our own queue length */
2286 dev->tx_queue_len = TUN_READQ_SIZE;
2287}
2288
2289/* Trivial set of netlink ops to allow deleting tun or tap
2290 * device with netlink.
2291 */
2292static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
2293 struct netlink_ext_ack *extack)
2294{
2295 return -EINVAL;
2296}
2297
2298static size_t tun_get_size(const struct net_device *dev)
2299{
2300 BUILD_BUG_ON(sizeof(u32) != sizeof(uid_t));
2301 BUILD_BUG_ON(sizeof(u32) != sizeof(gid_t));
2302
2303 return nla_total_size(sizeof(uid_t)) + /* OWNER */
2304 nla_total_size(sizeof(gid_t)) + /* GROUP */
2305 nla_total_size(sizeof(u8)) + /* TYPE */
2306 nla_total_size(sizeof(u8)) + /* PI */
2307 nla_total_size(sizeof(u8)) + /* VNET_HDR */
2308 nla_total_size(sizeof(u8)) + /* PERSIST */
2309 nla_total_size(sizeof(u8)) + /* MULTI_QUEUE */
2310 nla_total_size(sizeof(u32)) + /* NUM_QUEUES */
2311 nla_total_size(sizeof(u32)) + /* NUM_DISABLED_QUEUES */
2312 0;
2313}
2314
2315static int tun_fill_info(struct sk_buff *skb, const struct net_device *dev)
2316{
2317 struct tun_struct *tun = netdev_priv(dev);
2318
2319 if (nla_put_u8(skb, IFLA_TUN_TYPE, tun->flags & TUN_TYPE_MASK))
2320 goto nla_put_failure;
2321 if (uid_valid(tun->owner) &&
2322 nla_put_u32(skb, IFLA_TUN_OWNER,
2323 from_kuid_munged(current_user_ns(), tun->owner)))
2324 goto nla_put_failure;
2325 if (gid_valid(tun->group) &&
2326 nla_put_u32(skb, IFLA_TUN_GROUP,
2327 from_kgid_munged(current_user_ns(), tun->group)))
2328 goto nla_put_failure;
2329 if (nla_put_u8(skb, IFLA_TUN_PI, !(tun->flags & IFF_NO_PI)))
2330 goto nla_put_failure;
2331 if (nla_put_u8(skb, IFLA_TUN_VNET_HDR, !!(tun->flags & IFF_VNET_HDR)))
2332 goto nla_put_failure;
2333 if (nla_put_u8(skb, IFLA_TUN_PERSIST, !!(tun->flags & IFF_PERSIST)))
2334 goto nla_put_failure;
2335 if (nla_put_u8(skb, IFLA_TUN_MULTI_QUEUE,
2336 !!(tun->flags & IFF_MULTI_QUEUE)))
2337 goto nla_put_failure;
2338 if (tun->flags & IFF_MULTI_QUEUE) {
2339 if (nla_put_u32(skb, IFLA_TUN_NUM_QUEUES, tun->numqueues))
2340 goto nla_put_failure;
2341 if (nla_put_u32(skb, IFLA_TUN_NUM_DISABLED_QUEUES,
2342 tun->numdisabled))
2343 goto nla_put_failure;
2344 }
2345
2346 return 0;
2347
2348nla_put_failure:
2349 return -EMSGSIZE;
2350}
2351
2352static struct rtnl_link_ops tun_link_ops __read_mostly = {
2353 .kind = DRV_NAME,
2354 .priv_size = sizeof(struct tun_struct),
2355 .setup = tun_setup,
2356 .validate = tun_validate,
2357 .get_size = tun_get_size,
2358 .fill_info = tun_fill_info,
2359};
2360
2361static void tun_sock_write_space(struct sock *sk)
2362{
2363 struct tun_file *tfile;
2364 wait_queue_head_t *wqueue;
2365
2366 if (!sock_writeable(sk))
2367 return;
2368
2369 if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
2370 return;
2371
2372 wqueue = sk_sleep(sk);
2373 if (wqueue && waitqueue_active(wqueue))
2374 wake_up_interruptible_sync_poll(wqueue, EPOLLOUT |
2375 EPOLLWRNORM | EPOLLWRBAND);
2376
2377 tfile = container_of(sk, struct tun_file, sk);
2378 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
2379}
2380
2381static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
2382{
2383 int ret;
2384 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2385 struct tun_struct *tun = tun_get(tfile);
2386
2387 if (!tun)
2388 return -EBADFD;
2389
2390 ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter,
2391 m->msg_flags & MSG_DONTWAIT,
2392 m->msg_flags & MSG_MORE);
2393 tun_put(tun);
2394 return ret;
2395}
2396
2397static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
2398 int flags)
2399{
2400 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2401 struct tun_struct *tun = tun_get(tfile);
2402 void *ptr = m->msg_control;
2403 int ret;
2404
2405 if (!tun) {
2406 ret = -EBADFD;
2407 goto out_free;
2408 }
2409
2410 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
2411 ret = -EINVAL;
2412 goto out_put_tun;
2413 }
2414 if (flags & MSG_ERRQUEUE) {
2415 ret = sock_recv_errqueue(sock->sk, m, total_len,
2416 SOL_PACKET, TUN_TX_TIMESTAMP);
2417 goto out;
2418 }
2419 ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT, ptr);
2420 if (ret > (ssize_t)total_len) {
2421 m->msg_flags |= MSG_TRUNC;
2422 ret = flags & MSG_TRUNC ? ret : total_len;
2423 }
2424out:
2425 tun_put(tun);
2426 return ret;
2427
2428out_put_tun:
2429 tun_put(tun);
2430out_free:
2431 tun_ptr_free(ptr);
2432 return ret;
2433}
2434
2435static int tun_ptr_peek_len(void *ptr)
2436{
2437 if (likely(ptr)) {
2438 if (tun_is_xdp_buff(ptr)) {
2439 struct xdp_buff *xdp = tun_ptr_to_xdp(ptr);
2440
2441 return xdp->data_end - xdp->data;
2442 }
2443 return __skb_array_len_with_tag(ptr);
2444 } else {
2445 return 0;
2446 }
2447}
2448
2449static int tun_peek_len(struct socket *sock)
2450{
2451 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
2452 struct tun_struct *tun;
2453 int ret = 0;
2454
2455 tun = tun_get(tfile);
2456 if (!tun)
2457 return 0;
2458
2459 ret = PTR_RING_PEEK_CALL(&tfile->tx_ring, tun_ptr_peek_len);
2460 tun_put(tun);
2461
2462 return ret;
2463}
2464
2465/* Ops structure to mimic raw sockets with tun */
2466static const struct proto_ops tun_socket_ops = {
2467 .peek_len = tun_peek_len,
2468 .sendmsg = tun_sendmsg,
2469 .recvmsg = tun_recvmsg,
2470};
2471
2472static struct proto tun_proto = {
2473 .name = "tun",
2474 .owner = THIS_MODULE,
2475 .obj_size = sizeof(struct tun_file),
2476};
2477
2478static int tun_flags(struct tun_struct *tun)
2479{
2480 return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
2481}
2482
2483static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
2484 char *buf)
2485{
2486 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2487 return sprintf(buf, "0x%x\n", tun_flags(tun));
2488}
2489
2490static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
2491 char *buf)
2492{
2493 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2494 return uid_valid(tun->owner)?
2495 sprintf(buf, "%u\n",
2496 from_kuid_munged(current_user_ns(), tun->owner)):
2497 sprintf(buf, "-1\n");
2498}
2499
2500static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
2501 char *buf)
2502{
2503 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
2504 return gid_valid(tun->group) ?
2505 sprintf(buf, "%u\n",
2506 from_kgid_munged(current_user_ns(), tun->group)):
2507 sprintf(buf, "-1\n");
2508}
2509
2510static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
2511static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
2512static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
2513
2514static struct attribute *tun_dev_attrs[] = {
2515 &dev_attr_tun_flags.attr,
2516 &dev_attr_owner.attr,
2517 &dev_attr_group.attr,
2518 NULL
2519};
2520
2521static const struct attribute_group tun_attr_group = {
2522 .attrs = tun_dev_attrs
2523};
2524
2525static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
2526{
2527 struct tun_struct *tun;
2528 struct tun_file *tfile = file->private_data;
2529 struct net_device *dev;
2530 int err;
2531
2532 if (tfile->detached)
2533 return -EINVAL;
2534
2535 if ((ifr->ifr_flags & IFF_NAPI_FRAGS)) {
2536 if (!capable(CAP_NET_ADMIN))
2537 return -EPERM;
2538
2539 if (!(ifr->ifr_flags & IFF_NAPI) ||
2540 (ifr->ifr_flags & TUN_TYPE_MASK) != IFF_TAP)
2541 return -EINVAL;
2542 }
2543
2544 dev = __dev_get_by_name(net, ifr->ifr_name);
2545 if (dev) {
2546 if (ifr->ifr_flags & IFF_TUN_EXCL)
2547 return -EBUSY;
2548 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
2549 tun = netdev_priv(dev);
2550 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
2551 tun = netdev_priv(dev);
2552 else
2553 return -EINVAL;
2554
2555 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
2556 !!(tun->flags & IFF_MULTI_QUEUE))
2557 return -EINVAL;
2558
2559 if (tun_not_capable(tun))
2560 return -EPERM;
2561 err = security_tun_dev_open(tun->security);
2562 if (err < 0)
2563 return err;
2564
2565 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER,
2566 ifr->ifr_flags & IFF_NAPI);
2567 if (err < 0)
2568 return err;
2569
2570 if (tun->flags & IFF_MULTI_QUEUE &&
2571 (tun->numqueues + tun->numdisabled > 1)) {
2572 /* One or more queue has already been attached, no need
2573 * to initialize the device again.
2574 */
2575 netdev_state_change(dev);
2576 return 0;
2577 }
2578
2579 tun->flags = (tun->flags & ~TUN_FEATURES) |
2580 (ifr->ifr_flags & TUN_FEATURES);
2581
2582 netdev_state_change(dev);
2583 } else {
2584 char *name;
2585 unsigned long flags = 0;
2586 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
2587 MAX_TAP_QUEUES : 1;
2588
2589 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2590 return -EPERM;
2591 err = security_tun_dev_create();
2592 if (err < 0)
2593 return err;
2594
2595 /* Set dev type */
2596 if (ifr->ifr_flags & IFF_TUN) {
2597 /* TUN device */
2598 flags |= IFF_TUN;
2599 name = "tun%d";
2600 } else if (ifr->ifr_flags & IFF_TAP) {
2601 /* TAP device */
2602 flags |= IFF_TAP;
2603 name = "tap%d";
2604 } else
2605 return -EINVAL;
2606
2607 if (*ifr->ifr_name)
2608 name = ifr->ifr_name;
2609
2610 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
2611 NET_NAME_UNKNOWN, tun_setup, queues,
2612 queues);
2613
2614 if (!dev)
2615 return -ENOMEM;
2616 err = dev_get_valid_name(net, dev, name);
2617 if (err < 0)
2618 goto err_free_dev;
2619
2620 dev_net_set(dev, net);
2621 dev->rtnl_link_ops = &tun_link_ops;
2622 dev->ifindex = tfile->ifindex;
2623 dev->sysfs_groups[0] = &tun_attr_group;
2624
2625 tun = netdev_priv(dev);
2626 tun->dev = dev;
2627 tun->flags = flags;
2628 tun->txflt.count = 0;
2629 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
2630
2631 tun->align = NET_SKB_PAD;
2632 tun->filter_attached = false;
2633 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
2634 tun->rx_batched = 0;
2635 RCU_INIT_POINTER(tun->steering_prog, NULL);
2636
2637 tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats);
2638 if (!tun->pcpu_stats) {
2639 err = -ENOMEM;
2640 goto err_free_dev;
2641 }
2642
2643 spin_lock_init(&tun->lock);
2644
2645 err = security_tun_dev_alloc_security(&tun->security);
2646 if (err < 0)
2647 goto err_free_stat;
2648
2649 tun_net_init(dev);
2650 tun_flow_init(tun);
2651
2652 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
2653 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
2654 NETIF_F_HW_VLAN_STAG_TX;
2655 dev->features = dev->hw_features | NETIF_F_LLTX;
2656 dev->vlan_features = dev->features &
2657 ~(NETIF_F_HW_VLAN_CTAG_TX |
2658 NETIF_F_HW_VLAN_STAG_TX);
2659
2660 tun->flags = (tun->flags & ~TUN_FEATURES) |
2661 (ifr->ifr_flags & TUN_FEATURES);
2662
2663 INIT_LIST_HEAD(&tun->disabled);
2664 err = tun_attach(tun, file, false, ifr->ifr_flags & IFF_NAPI);
2665 if (err < 0)
2666 goto err_free_flow;
2667
2668 err = register_netdevice(tun->dev);
2669 if (err < 0)
2670 goto err_detach;
2671 }
2672
2673 netif_carrier_on(tun->dev);
2674
2675 tun_debug(KERN_INFO, tun, "tun_set_iff\n");
2676
2677 /* Make sure persistent devices do not get stuck in
2678 * xoff state.
2679 */
2680 if (netif_running(tun->dev))
2681 netif_tx_wake_all_queues(tun->dev);
2682
2683 strcpy(ifr->ifr_name, tun->dev->name);
2684 return 0;
2685
2686err_detach:
2687 tun_detach_all(dev);
2688 /* register_netdevice() already called tun_free_netdev() */
2689 goto err_free_dev;
2690
2691err_free_flow:
2692 tun_flow_uninit(tun);
2693 security_tun_dev_free_security(tun->security);
2694err_free_stat:
2695 free_percpu(tun->pcpu_stats);
2696err_free_dev:
2697 free_netdev(dev);
2698 return err;
2699}
2700
2701static void tun_get_iff(struct net *net, struct tun_struct *tun,
2702 struct ifreq *ifr)
2703{
2704 tun_debug(KERN_INFO, tun, "tun_get_iff\n");
2705
2706 strcpy(ifr->ifr_name, tun->dev->name);
2707
2708 ifr->ifr_flags = tun_flags(tun);
2709
2710}
2711
2712/* This is like a cut-down ethtool ops, except done via tun fd so no
2713 * privs required. */
2714static int set_offload(struct tun_struct *tun, unsigned long arg)
2715{
2716 netdev_features_t features = 0;
2717
2718 if (arg & TUN_F_CSUM) {
2719 features |= NETIF_F_HW_CSUM;
2720 arg &= ~TUN_F_CSUM;
2721
2722 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
2723 if (arg & TUN_F_TSO_ECN) {
2724 features |= NETIF_F_TSO_ECN;
2725 arg &= ~TUN_F_TSO_ECN;
2726 }
2727 if (arg & TUN_F_TSO4)
2728 features |= NETIF_F_TSO;
2729 if (arg & TUN_F_TSO6)
2730 features |= NETIF_F_TSO6;
2731 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
2732 }
2733
2734 arg &= ~TUN_F_UFO;
2735 }
2736
2737 /* This gives the user a way to test for new features in future by
2738 * trying to set them. */
2739 if (arg)
2740 return -EINVAL;
2741
2742 tun->set_features = features;
2743 tun->dev->wanted_features &= ~TUN_USER_FEATURES;
2744 tun->dev->wanted_features |= features;
2745 netdev_update_features(tun->dev);
2746
2747 return 0;
2748}
2749
2750static void tun_detach_filter(struct tun_struct *tun, int n)
2751{
2752 int i;
2753 struct tun_file *tfile;
2754
2755 for (i = 0; i < n; i++) {
2756 tfile = rtnl_dereference(tun->tfiles[i]);
2757 lock_sock(tfile->socket.sk);
2758 sk_detach_filter(tfile->socket.sk);
2759 release_sock(tfile->socket.sk);
2760 }
2761
2762 tun->filter_attached = false;
2763}
2764
2765static int tun_attach_filter(struct tun_struct *tun)
2766{
2767 int i, ret = 0;
2768 struct tun_file *tfile;
2769
2770 for (i = 0; i < tun->numqueues; i++) {
2771 tfile = rtnl_dereference(tun->tfiles[i]);
2772 lock_sock(tfile->socket.sk);
2773 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
2774 release_sock(tfile->socket.sk);
2775 if (ret) {
2776 tun_detach_filter(tun, i);
2777 return ret;
2778 }
2779 }
2780
2781 tun->filter_attached = true;
2782 return ret;
2783}
2784
2785static void tun_set_sndbuf(struct tun_struct *tun)
2786{
2787 struct tun_file *tfile;
2788 int i;
2789
2790 for (i = 0; i < tun->numqueues; i++) {
2791 tfile = rtnl_dereference(tun->tfiles[i]);
2792 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
2793 }
2794}
2795
2796static int tun_set_queue(struct file *file, struct ifreq *ifr)
2797{
2798 struct tun_file *tfile = file->private_data;
2799 struct tun_struct *tun;
2800 int ret = 0;
2801
2802 rtnl_lock();
2803
2804 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
2805 tun = tfile->detached;
2806 if (!tun) {
2807 ret = -EINVAL;
2808 goto unlock;
2809 }
2810 ret = security_tun_dev_attach_queue(tun->security);
2811 if (ret < 0)
2812 goto unlock;
2813 ret = tun_attach(tun, file, false, tun->flags & IFF_NAPI);
2814 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
2815 tun = rtnl_dereference(tfile->tun);
2816 if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
2817 ret = -EINVAL;
2818 else
2819 __tun_detach(tfile, false);
2820 } else
2821 ret = -EINVAL;
2822
2823 if (ret >= 0)
2824 netdev_state_change(tun->dev);
2825
2826unlock:
2827 rtnl_unlock();
2828 return ret;
2829}
2830
2831static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog **prog_p,
2832 void __user *data)
2833{
2834 struct bpf_prog *prog;
2835 int fd;
2836
2837 if (copy_from_user(&fd, data, sizeof(fd)))
2838 return -EFAULT;
2839
2840 if (fd == -1) {
2841 prog = NULL;
2842 } else {
2843 prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
2844 if (IS_ERR(prog))
2845 return PTR_ERR(prog);
2846 }
2847
2848 return __tun_set_ebpf(tun, prog_p, prog);
2849}
2850
2851static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
2852 unsigned long arg, int ifreq_len)
2853{
2854 struct tun_file *tfile = file->private_data;
2855 struct tun_struct *tun;
2856 void __user* argp = (void __user*)arg;
2857 struct ifreq ifr;
2858 struct net *net;
2859 kuid_t owner;
2860 kgid_t group;
2861 int sndbuf;
2862 int vnet_hdr_sz;
2863 unsigned int ifindex;
2864 int le;
2865 int ret;
2866 bool do_notify = false;
2867
2868 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE ||
2869 (_IOC_TYPE(cmd) == SOCK_IOC_TYPE && cmd != SIOCGSKNS)) {
2870 if (copy_from_user(&ifr, argp, ifreq_len))
2871 return -EFAULT;
2872 } else {
2873 memset(&ifr, 0, sizeof(ifr));
2874 }
2875 if (cmd == TUNGETFEATURES) {
2876 /* Currently this just means: "what IFF flags are valid?".
2877 * This is needed because we never checked for invalid flags on
2878 * TUNSETIFF.
2879 */
2880 return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
2881 (unsigned int __user*)argp);
2882 } else if (cmd == TUNSETQUEUE)
2883 return tun_set_queue(file, &ifr);
2884
2885 ret = 0;
2886 rtnl_lock();
2887
2888 tun = tun_get(tfile);
2889 net = sock_net(&tfile->sk);
2890 if (cmd == TUNSETIFF) {
2891 ret = -EEXIST;
2892 if (tun)
2893 goto unlock;
2894
2895 ifr.ifr_name[IFNAMSIZ-1] = '\0';
2896
2897 ret = tun_set_iff(net, file, &ifr);
2898
2899 if (ret)
2900 goto unlock;
2901
2902 if (copy_to_user(argp, &ifr, ifreq_len))
2903 ret = -EFAULT;
2904 goto unlock;
2905 }
2906 if (cmd == TUNSETIFINDEX) {
2907 ret = -EPERM;
2908 if (tun)
2909 goto unlock;
2910
2911 ret = -EFAULT;
2912 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
2913 goto unlock;
2914
2915 ret = 0;
2916 tfile->ifindex = ifindex;
2917 goto unlock;
2918 }
2919 if (cmd == SIOCGSKNS) {
2920 ret = -EPERM;
2921 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
2922 goto unlock;
2923
2924 ret = open_related_ns(&net->ns, get_net_ns);
2925 goto unlock;
2926 }
2927
2928 ret = -EBADFD;
2929 if (!tun)
2930 goto unlock;
2931
2932 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
2933
2934 ret = 0;
2935 switch (cmd) {
2936 case TUNGETIFF:
2937 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2938
2939 if (tfile->detached)
2940 ifr.ifr_flags |= IFF_DETACH_QUEUE;
2941 if (!tfile->socket.sk->sk_filter)
2942 ifr.ifr_flags |= IFF_NOFILTER;
2943
2944 if (copy_to_user(argp, &ifr, ifreq_len))
2945 ret = -EFAULT;
2946 break;
2947
2948 case TUNSETNOCSUM:
2949 /* Disable/Enable checksum */
2950
2951 /* [unimplemented] */
2952 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
2953 arg ? "disabled" : "enabled");
2954 break;
2955
2956 case TUNSETPERSIST:
2957 /* Disable/Enable persist mode. Keep an extra reference to the
2958 * module to prevent the module being unprobed.
2959 */
2960 if (arg && !(tun->flags & IFF_PERSIST)) {
2961 tun->flags |= IFF_PERSIST;
2962 __module_get(THIS_MODULE);
2963 do_notify = true;
2964 }
2965 if (!arg && (tun->flags & IFF_PERSIST)) {
2966 tun->flags &= ~IFF_PERSIST;
2967 module_put(THIS_MODULE);
2968 do_notify = true;
2969 }
2970
2971 tun_debug(KERN_INFO, tun, "persist %s\n",
2972 arg ? "enabled" : "disabled");
2973 break;
2974
2975 case TUNSETOWNER:
2976 /* Set owner of the device */
2977 owner = make_kuid(current_user_ns(), arg);
2978 if (!uid_valid(owner)) {
2979 ret = -EINVAL;
2980 break;
2981 }
2982 tun->owner = owner;
2983 do_notify = true;
2984 tun_debug(KERN_INFO, tun, "owner set to %u\n",
2985 from_kuid(&init_user_ns, tun->owner));
2986 break;
2987
2988 case TUNSETGROUP:
2989 /* Set group of the device */
2990 group = make_kgid(current_user_ns(), arg);
2991 if (!gid_valid(group)) {
2992 ret = -EINVAL;
2993 break;
2994 }
2995 tun->group = group;
2996 do_notify = true;
2997 tun_debug(KERN_INFO, tun, "group set to %u\n",
2998 from_kgid(&init_user_ns, tun->group));
2999 break;
3000
3001 case TUNSETLINK:
3002 /* Only allow setting the type when the interface is down */
3003 if (tun->dev->flags & IFF_UP) {
3004 tun_debug(KERN_INFO, tun,
3005 "Linktype set failed because interface is up\n");
3006 ret = -EBUSY;
3007 } else {
3008 tun->dev->type = (int) arg;
3009 tun_debug(KERN_INFO, tun, "linktype set to %d\n",
3010 tun->dev->type);
3011 ret = 0;
3012 }
3013 break;
3014
3015#ifdef TUN_DEBUG
3016 case TUNSETDEBUG:
3017 tun->debug = arg;
3018 break;
3019#endif
3020 case TUNSETOFFLOAD:
3021 ret = set_offload(tun, arg);
3022 break;
3023
3024 case TUNSETTXFILTER:
3025 /* Can be set only for TAPs */
3026 ret = -EINVAL;
3027 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3028 break;
3029 ret = update_filter(&tun->txflt, (void __user *)arg);
3030 break;
3031
3032 case SIOCGIFHWADDR:
3033 /* Get hw address */
3034 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
3035 ifr.ifr_hwaddr.sa_family = tun->dev->type;
3036 if (copy_to_user(argp, &ifr, ifreq_len))
3037 ret = -EFAULT;
3038 break;
3039
3040 case SIOCSIFHWADDR:
3041 /* Set hw address */
3042 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
3043 ifr.ifr_hwaddr.sa_data);
3044
3045 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
3046 break;
3047
3048 case TUNGETSNDBUF:
3049 sndbuf = tfile->socket.sk->sk_sndbuf;
3050 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
3051 ret = -EFAULT;
3052 break;
3053
3054 case TUNSETSNDBUF:
3055 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
3056 ret = -EFAULT;
3057 break;
3058 }
3059 if (sndbuf <= 0) {
3060 ret = -EINVAL;
3061 break;
3062 }
3063
3064 tun->sndbuf = sndbuf;
3065 tun_set_sndbuf(tun);
3066 break;
3067
3068 case TUNGETVNETHDRSZ:
3069 vnet_hdr_sz = tun->vnet_hdr_sz;
3070 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
3071 ret = -EFAULT;
3072 break;
3073
3074 case TUNSETVNETHDRSZ:
3075 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
3076 ret = -EFAULT;
3077 break;
3078 }
3079 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
3080 ret = -EINVAL;
3081 break;
3082 }
3083
3084 tun->vnet_hdr_sz = vnet_hdr_sz;
3085 break;
3086
3087 case TUNGETVNETLE:
3088 le = !!(tun->flags & TUN_VNET_LE);
3089 if (put_user(le, (int __user *)argp))
3090 ret = -EFAULT;
3091 break;
3092
3093 case TUNSETVNETLE:
3094 if (get_user(le, (int __user *)argp)) {
3095 ret = -EFAULT;
3096 break;
3097 }
3098 if (le)
3099 tun->flags |= TUN_VNET_LE;
3100 else
3101 tun->flags &= ~TUN_VNET_LE;
3102 break;
3103
3104 case TUNGETVNETBE:
3105 ret = tun_get_vnet_be(tun, argp);
3106 break;
3107
3108 case TUNSETVNETBE:
3109 ret = tun_set_vnet_be(tun, argp);
3110 break;
3111
3112 case TUNATTACHFILTER:
3113 /* Can be set only for TAPs */
3114 ret = -EINVAL;
3115 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3116 break;
3117 ret = -EFAULT;
3118 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
3119 break;
3120
3121 ret = tun_attach_filter(tun);
3122 break;
3123
3124 case TUNDETACHFILTER:
3125 /* Can be set only for TAPs */
3126 ret = -EINVAL;
3127 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3128 break;
3129 ret = 0;
3130 tun_detach_filter(tun, tun->numqueues);
3131 break;
3132
3133 case TUNGETFILTER:
3134 ret = -EINVAL;
3135 if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
3136 break;
3137 ret = -EFAULT;
3138 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
3139 break;
3140 ret = 0;
3141 break;
3142
3143 case TUNSETSTEERINGEBPF:
3144 ret = tun_set_ebpf(tun, &tun->steering_prog, argp);
3145 break;
3146
3147 case TUNSETFILTEREBPF:
3148 ret = tun_set_ebpf(tun, &tun->filter_prog, argp);
3149 break;
3150
3151 default:
3152 ret = -EINVAL;
3153 break;
3154 }
3155
3156 if (do_notify)
3157 netdev_state_change(tun->dev);
3158
3159unlock:
3160 rtnl_unlock();
3161 if (tun)
3162 tun_put(tun);
3163 return ret;
3164}
3165
3166static long tun_chr_ioctl(struct file *file,
3167 unsigned int cmd, unsigned long arg)
3168{
3169 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
3170}
3171
3172#ifdef CONFIG_COMPAT
3173static long tun_chr_compat_ioctl(struct file *file,
3174 unsigned int cmd, unsigned long arg)
3175{
3176 switch (cmd) {
3177 case TUNSETIFF:
3178 case TUNGETIFF:
3179 case TUNSETTXFILTER:
3180 case TUNGETSNDBUF:
3181 case TUNSETSNDBUF:
3182 case SIOCGIFHWADDR:
3183 case SIOCSIFHWADDR:
3184 arg = (unsigned long)compat_ptr(arg);
3185 break;
3186 default:
3187 arg = (compat_ulong_t)arg;
3188 break;
3189 }
3190
3191 /*
3192 * compat_ifreq is shorter than ifreq, so we must not access beyond
3193 * the end of that structure. All fields that are used in this
3194 * driver are compatible though, we don't need to convert the
3195 * contents.
3196 */
3197 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
3198}
3199#endif /* CONFIG_COMPAT */
3200
3201static int tun_chr_fasync(int fd, struct file *file, int on)
3202{
3203 struct tun_file *tfile = file->private_data;
3204 int ret;
3205
3206 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
3207 goto out;
3208
3209 if (on) {
3210 __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
3211 tfile->flags |= TUN_FASYNC;
3212 } else
3213 tfile->flags &= ~TUN_FASYNC;
3214 ret = 0;
3215out:
3216 return ret;
3217}
3218
3219static int tun_chr_open(struct inode *inode, struct file * file)
3220{
3221 struct net *net = current->nsproxy->net_ns;
3222 struct tun_file *tfile;
3223
3224 DBG1(KERN_INFO, "tunX: tun_chr_open\n");
3225
3226 tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
3227 &tun_proto, 0);
3228 if (!tfile)
3229 return -ENOMEM;
3230 if (ptr_ring_init(&tfile->tx_ring, 0, GFP_KERNEL)) {
3231 sk_free(&tfile->sk);
3232 return -ENOMEM;
3233 }
3234
3235 RCU_INIT_POINTER(tfile->tun, NULL);
3236 tfile->flags = 0;
3237 tfile->ifindex = 0;
3238
3239 init_waitqueue_head(&tfile->wq.wait);
3240 RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq);
3241
3242 tfile->socket.file = file;
3243 tfile->socket.ops = &tun_socket_ops;
3244
3245 sock_init_data(&tfile->socket, &tfile->sk);
3246
3247 tfile->sk.sk_write_space = tun_sock_write_space;
3248 tfile->sk.sk_sndbuf = INT_MAX;
3249
3250 file->private_data = tfile;
3251 INIT_LIST_HEAD(&tfile->next);
3252
3253 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
3254
3255 return 0;
3256}
3257
3258static int tun_chr_close(struct inode *inode, struct file *file)
3259{
3260 struct tun_file *tfile = file->private_data;
3261
3262 tun_detach(tfile, true);
3263
3264 return 0;
3265}
3266
3267#ifdef CONFIG_PROC_FS
3268static void tun_chr_show_fdinfo(struct seq_file *m, struct file *file)
3269{
3270 struct tun_file *tfile = file->private_data;
3271 struct tun_struct *tun;
3272 struct ifreq ifr;
3273
3274 memset(&ifr, 0, sizeof(ifr));
3275
3276 rtnl_lock();
3277 tun = tun_get(tfile);
3278 if (tun)
3279 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
3280 rtnl_unlock();
3281
3282 if (tun)
3283 tun_put(tun);
3284
3285 seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
3286}
3287#endif
3288
3289static const struct file_operations tun_fops = {
3290 .owner = THIS_MODULE,
3291 .llseek = no_llseek,
3292 .read_iter = tun_chr_read_iter,
3293 .write_iter = tun_chr_write_iter,
3294 .poll = tun_chr_poll,
3295 .unlocked_ioctl = tun_chr_ioctl,
3296#ifdef CONFIG_COMPAT
3297 .compat_ioctl = tun_chr_compat_ioctl,
3298#endif
3299 .open = tun_chr_open,
3300 .release = tun_chr_close,
3301 .fasync = tun_chr_fasync,
3302#ifdef CONFIG_PROC_FS
3303 .show_fdinfo = tun_chr_show_fdinfo,
3304#endif
3305};
3306
3307static struct miscdevice tun_miscdev = {
3308 .minor = TUN_MINOR,
3309 .name = "tun",
3310 .nodename = "net/tun",
3311 .fops = &tun_fops,
3312};
3313
3314/* ethtool interface */
3315
3316static int tun_get_link_ksettings(struct net_device *dev,
3317 struct ethtool_link_ksettings *cmd)
3318{
3319 ethtool_link_ksettings_zero_link_mode(cmd, supported);
3320 ethtool_link_ksettings_zero_link_mode(cmd, advertising);
3321 cmd->base.speed = SPEED_10;
3322 cmd->base.duplex = DUPLEX_FULL;
3323 cmd->base.port = PORT_TP;
3324 cmd->base.phy_address = 0;
3325 cmd->base.autoneg = AUTONEG_DISABLE;
3326 return 0;
3327}
3328
3329static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
3330{
3331 struct tun_struct *tun = netdev_priv(dev);
3332
3333 strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
3334 strlcpy(info->version, DRV_VERSION, sizeof(info->version));
3335
3336 switch (tun->flags & TUN_TYPE_MASK) {
3337 case IFF_TUN:
3338 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
3339 break;
3340 case IFF_TAP:
3341 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
3342 break;
3343 }
3344}
3345
3346static u32 tun_get_msglevel(struct net_device *dev)
3347{
3348#ifdef TUN_DEBUG
3349 struct tun_struct *tun = netdev_priv(dev);
3350 return tun->debug;
3351#else
3352 return -EOPNOTSUPP;
3353#endif
3354}
3355
3356static void tun_set_msglevel(struct net_device *dev, u32 value)
3357{
3358#ifdef TUN_DEBUG
3359 struct tun_struct *tun = netdev_priv(dev);
3360 tun->debug = value;
3361#endif
3362}
3363
3364static int tun_get_coalesce(struct net_device *dev,
3365 struct ethtool_coalesce *ec)
3366{
3367 struct tun_struct *tun = netdev_priv(dev);
3368
3369 ec->rx_max_coalesced_frames = tun->rx_batched;
3370
3371 return 0;
3372}
3373
3374static int tun_set_coalesce(struct net_device *dev,
3375 struct ethtool_coalesce *ec)
3376{
3377 struct tun_struct *tun = netdev_priv(dev);
3378
3379 if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT)
3380 tun->rx_batched = NAPI_POLL_WEIGHT;
3381 else
3382 tun->rx_batched = ec->rx_max_coalesced_frames;
3383
3384 return 0;
3385}
3386
3387static const struct ethtool_ops tun_ethtool_ops = {
3388 .get_drvinfo = tun_get_drvinfo,
3389 .get_msglevel = tun_get_msglevel,
3390 .set_msglevel = tun_set_msglevel,
3391 .get_link = ethtool_op_get_link,
3392 .get_ts_info = ethtool_op_get_ts_info,
3393 .get_coalesce = tun_get_coalesce,
3394 .set_coalesce = tun_set_coalesce,
3395 .get_link_ksettings = tun_get_link_ksettings,
3396};
3397
3398static int tun_queue_resize(struct tun_struct *tun)
3399{
3400 struct net_device *dev = tun->dev;
3401 struct tun_file *tfile;
3402 struct ptr_ring **rings;
3403 int n = tun->numqueues + tun->numdisabled;
3404 int ret, i;
3405
3406 rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL);
3407 if (!rings)
3408 return -ENOMEM;
3409
3410 for (i = 0; i < tun->numqueues; i++) {
3411 tfile = rtnl_dereference(tun->tfiles[i]);
3412 rings[i] = &tfile->tx_ring;
3413 }
3414 list_for_each_entry(tfile, &tun->disabled, next)
3415 rings[i++] = &tfile->tx_ring;
3416
3417 ret = ptr_ring_resize_multiple(rings, n,
3418 dev->tx_queue_len, GFP_KERNEL,
3419 tun_ptr_free);
3420
3421 kfree(rings);
3422 return ret;
3423}
3424
3425static int tun_device_event(struct notifier_block *unused,
3426 unsigned long event, void *ptr)
3427{
3428 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3429 struct tun_struct *tun = netdev_priv(dev);
3430
3431 if (dev->rtnl_link_ops != &tun_link_ops)
3432 return NOTIFY_DONE;
3433
3434 switch (event) {
3435 case NETDEV_CHANGE_TX_QUEUE_LEN:
3436 if (tun_queue_resize(tun))
3437 return NOTIFY_BAD;
3438 break;
3439 default:
3440 break;
3441 }
3442
3443 return NOTIFY_DONE;
3444}
3445
3446static struct notifier_block tun_notifier_block __read_mostly = {
3447 .notifier_call = tun_device_event,
3448};
3449
3450static int __init tun_init(void)
3451{
3452 int ret = 0;
3453
3454 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
3455
3456 ret = rtnl_link_register(&tun_link_ops);
3457 if (ret) {
3458 pr_err("Can't register link_ops\n");
3459 goto err_linkops;
3460 }
3461
3462 ret = misc_register(&tun_miscdev);
3463 if (ret) {
3464 pr_err("Can't register misc device %d\n", TUN_MINOR);
3465 goto err_misc;
3466 }
3467
3468 ret = register_netdevice_notifier(&tun_notifier_block);
3469 if (ret) {
3470 pr_err("Can't register netdevice notifier\n");
3471 goto err_notifier;
3472 }
3473
3474 return 0;
3475
3476err_notifier:
3477 misc_deregister(&tun_miscdev);
3478err_misc:
3479 rtnl_link_unregister(&tun_link_ops);
3480err_linkops:
3481 return ret;
3482}
3483
3484static void tun_cleanup(void)
3485{
3486 misc_deregister(&tun_miscdev);
3487 rtnl_link_unregister(&tun_link_ops);
3488 unregister_netdevice_notifier(&tun_notifier_block);
3489}
3490
3491/* Get an underlying socket object from tun file. Returns error unless file is
3492 * attached to a device. The returned object works like a packet socket, it
3493 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
3494 * holding a reference to the file for as long as the socket is in use. */
3495struct socket *tun_get_socket(struct file *file)
3496{
3497 struct tun_file *tfile;
3498 if (file->f_op != &tun_fops)
3499 return ERR_PTR(-EINVAL);
3500 tfile = file->private_data;
3501 if (!tfile)
3502 return ERR_PTR(-EBADFD);
3503 return &tfile->socket;
3504}
3505EXPORT_SYMBOL_GPL(tun_get_socket);
3506
3507struct ptr_ring *tun_get_tx_ring(struct file *file)
3508{
3509 struct tun_file *tfile;
3510
3511 if (file->f_op != &tun_fops)
3512 return ERR_PTR(-EINVAL);
3513 tfile = file->private_data;
3514 if (!tfile)
3515 return ERR_PTR(-EBADFD);
3516 return &tfile->tx_ring;
3517}
3518EXPORT_SYMBOL_GPL(tun_get_tx_ring);
3519
3520module_init(tun_init);
3521module_exit(tun_cleanup);
3522MODULE_DESCRIPTION(DRV_DESCRIPTION);
3523MODULE_AUTHOR(DRV_COPYRIGHT);
3524MODULE_LICENSE("GPL");
3525MODULE_ALIAS_MISCDEV(TUN_MINOR);
3526MODULE_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
74#include <asm/uaccess.h>
75
76/* Uncomment to enable debugging */
77/* #define TUN_DEBUG 1 */
78
79#ifdef TUN_DEBUG
80static int debug;
81
82#define tun_debug(level, tun, fmt, args...) \
83do { \
84 if (tun->debug) \
85 netdev_printk(level, tun->dev, fmt, ##args); \
86} while (0)
87#define DBG1(level, fmt, args...) \
88do { \
89 if (debug == 2) \
90 printk(level fmt, ##args); \
91} while (0)
92#else
93#define tun_debug(level, tun, fmt, args...) \
94do { \
95 if (0) \
96 netdev_printk(level, tun->dev, fmt, ##args); \
97} while (0)
98#define DBG1(level, fmt, args...) \
99do { \
100 if (0) \
101 printk(level fmt, ##args); \
102} while (0)
103#endif
104
105#define GOODCOPY_LEN 128
106
107#define FLT_EXACT_COUNT 8
108struct tap_filter {
109 unsigned int count; /* Number of addrs. Zero means disabled */
110 u32 mask[2]; /* Mask of the hashed addrs */
111 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
112};
113
114/* DEFAULT_MAX_NUM_RSS_QUEUES were chosen to let the rx/tx queues allocated for
115 * the netdevice to be fit in one page. So we can make sure the success of
116 * memory allocation. TODO: increase the limit. */
117#define MAX_TAP_QUEUES DEFAULT_MAX_NUM_RSS_QUEUES
118#define MAX_TAP_FLOWS 4096
119
120#define TUN_FLOW_EXPIRE (3 * HZ)
121
122/* A tun_file connects an open character device to a tuntap netdevice. It
123 * also contains all socket related structures (except sock_fprog and tap_filter)
124 * to serve as one transmit queue for tuntap device. The sock_fprog and
125 * tap_filter were kept in tun_struct since they were used for filtering for the
126 * netdevice not for a specific queue (at least I didn't see the requirement for
127 * this).
128 *
129 * RCU usage:
130 * The tun_file and tun_struct are loosely coupled, the pointer from one to the
131 * other can only be read while rcu_read_lock or rtnl_lock is held.
132 */
133struct tun_file {
134 struct sock sk;
135 struct socket socket;
136 struct socket_wq wq;
137 struct tun_struct __rcu *tun;
138 struct net *net;
139 struct fasync_struct *fasync;
140 /* only used for fasnyc */
141 unsigned int flags;
142 union {
143 u16 queue_index;
144 unsigned int ifindex;
145 };
146 struct list_head next;
147 struct tun_struct *detached;
148};
149
150struct tun_flow_entry {
151 struct hlist_node hash_link;
152 struct rcu_head rcu;
153 struct tun_struct *tun;
154
155 u32 rxhash;
156 u32 rps_rxhash;
157 int queue_index;
158 unsigned long updated;
159};
160
161#define TUN_NUM_FLOW_ENTRIES 1024
162
163/* Since the socket were moved to tun_file, to preserve the behavior of persist
164 * device, socket filter, sndbuf and vnet header size were restore when the
165 * file were attached to a persist device.
166 */
167struct tun_struct {
168 struct tun_file __rcu *tfiles[MAX_TAP_QUEUES];
169 unsigned int numqueues;
170 unsigned int flags;
171 kuid_t owner;
172 kgid_t group;
173
174 struct net_device *dev;
175 netdev_features_t set_features;
176#define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
177 NETIF_F_TSO6|NETIF_F_UFO)
178
179 int vnet_hdr_sz;
180 int sndbuf;
181 struct tap_filter txflt;
182 struct sock_fprog fprog;
183 /* protected by rtnl lock */
184 bool filter_attached;
185#ifdef TUN_DEBUG
186 int debug;
187#endif
188 spinlock_t lock;
189 struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
190 struct timer_list flow_gc_timer;
191 unsigned long ageing_time;
192 unsigned int numdisabled;
193 struct list_head disabled;
194 void *security;
195 u32 flow_count;
196};
197
198static inline u32 tun_hashfn(u32 rxhash)
199{
200 return rxhash & 0x3ff;
201}
202
203static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
204{
205 struct tun_flow_entry *e;
206
207 hlist_for_each_entry_rcu(e, head, hash_link) {
208 if (e->rxhash == rxhash)
209 return e;
210 }
211 return NULL;
212}
213
214static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
215 struct hlist_head *head,
216 u32 rxhash, u16 queue_index)
217{
218 struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
219
220 if (e) {
221 tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
222 rxhash, queue_index);
223 e->updated = jiffies;
224 e->rxhash = rxhash;
225 e->rps_rxhash = 0;
226 e->queue_index = queue_index;
227 e->tun = tun;
228 hlist_add_head_rcu(&e->hash_link, head);
229 ++tun->flow_count;
230 }
231 return e;
232}
233
234static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
235{
236 tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
237 e->rxhash, e->queue_index);
238 sock_rps_reset_flow_hash(e->rps_rxhash);
239 hlist_del_rcu(&e->hash_link);
240 kfree_rcu(e, rcu);
241 --tun->flow_count;
242}
243
244static void tun_flow_flush(struct tun_struct *tun)
245{
246 int i;
247
248 spin_lock_bh(&tun->lock);
249 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
250 struct tun_flow_entry *e;
251 struct hlist_node *n;
252
253 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
254 tun_flow_delete(tun, e);
255 }
256 spin_unlock_bh(&tun->lock);
257}
258
259static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
260{
261 int i;
262
263 spin_lock_bh(&tun->lock);
264 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
265 struct tun_flow_entry *e;
266 struct hlist_node *n;
267
268 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
269 if (e->queue_index == queue_index)
270 tun_flow_delete(tun, e);
271 }
272 }
273 spin_unlock_bh(&tun->lock);
274}
275
276static void tun_flow_cleanup(unsigned long data)
277{
278 struct tun_struct *tun = (struct tun_struct *)data;
279 unsigned long delay = tun->ageing_time;
280 unsigned long next_timer = jiffies + delay;
281 unsigned long count = 0;
282 int i;
283
284 tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
285
286 spin_lock_bh(&tun->lock);
287 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
288 struct tun_flow_entry *e;
289 struct hlist_node *n;
290
291 hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
292 unsigned long this_timer;
293 count++;
294 this_timer = e->updated + delay;
295 if (time_before_eq(this_timer, jiffies))
296 tun_flow_delete(tun, e);
297 else if (time_before(this_timer, next_timer))
298 next_timer = this_timer;
299 }
300 }
301
302 if (count)
303 mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
304 spin_unlock_bh(&tun->lock);
305}
306
307static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
308 struct tun_file *tfile)
309{
310 struct hlist_head *head;
311 struct tun_flow_entry *e;
312 unsigned long delay = tun->ageing_time;
313 u16 queue_index = tfile->queue_index;
314
315 if (!rxhash)
316 return;
317 else
318 head = &tun->flows[tun_hashfn(rxhash)];
319
320 rcu_read_lock();
321
322 /* We may get a very small possibility of OOO during switching, not
323 * worth to optimize.*/
324 if (tun->numqueues == 1 || tfile->detached)
325 goto unlock;
326
327 e = tun_flow_find(head, rxhash);
328 if (likely(e)) {
329 /* TODO: keep queueing to old queue until it's empty? */
330 e->queue_index = queue_index;
331 e->updated = jiffies;
332 sock_rps_record_flow_hash(e->rps_rxhash);
333 } else {
334 spin_lock_bh(&tun->lock);
335 if (!tun_flow_find(head, rxhash) &&
336 tun->flow_count < MAX_TAP_FLOWS)
337 tun_flow_create(tun, head, rxhash, queue_index);
338
339 if (!timer_pending(&tun->flow_gc_timer))
340 mod_timer(&tun->flow_gc_timer,
341 round_jiffies_up(jiffies + delay));
342 spin_unlock_bh(&tun->lock);
343 }
344
345unlock:
346 rcu_read_unlock();
347}
348
349/**
350 * Save the hash received in the stack receive path and update the
351 * flow_hash table accordingly.
352 */
353static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
354{
355 if (unlikely(e->rps_rxhash != hash)) {
356 sock_rps_reset_flow_hash(e->rps_rxhash);
357 e->rps_rxhash = hash;
358 }
359}
360
361/* We try to identify a flow through its rxhash first. The reason that
362 * we do not check rxq no. is because some cards(e.g 82599), chooses
363 * the rxq based on the txq where the last packet of the flow comes. As
364 * the userspace application move between processors, we may get a
365 * different rxq no. here. If we could not get rxhash, then we would
366 * hope the rxq no. may help here.
367 */
368static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
369 void *accel_priv, select_queue_fallback_t fallback)
370{
371 struct tun_struct *tun = netdev_priv(dev);
372 struct tun_flow_entry *e;
373 u32 txq = 0;
374 u32 numqueues = 0;
375
376 rcu_read_lock();
377 numqueues = ACCESS_ONCE(tun->numqueues);
378
379 txq = skb_get_hash(skb);
380 if (txq) {
381 e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
382 if (e) {
383 tun_flow_save_rps_rxhash(e, txq);
384 txq = e->queue_index;
385 } else
386 /* use multiply and shift instead of expensive divide */
387 txq = ((u64)txq * numqueues) >> 32;
388 } else if (likely(skb_rx_queue_recorded(skb))) {
389 txq = skb_get_rx_queue(skb);
390 while (unlikely(txq >= numqueues))
391 txq -= numqueues;
392 }
393
394 rcu_read_unlock();
395 return txq;
396}
397
398static inline bool tun_not_capable(struct tun_struct *tun)
399{
400 const struct cred *cred = current_cred();
401 struct net *net = dev_net(tun->dev);
402
403 return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
404 (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
405 !ns_capable(net->user_ns, CAP_NET_ADMIN);
406}
407
408static void tun_set_real_num_queues(struct tun_struct *tun)
409{
410 netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
411 netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
412}
413
414static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
415{
416 tfile->detached = tun;
417 list_add_tail(&tfile->next, &tun->disabled);
418 ++tun->numdisabled;
419}
420
421static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
422{
423 struct tun_struct *tun = tfile->detached;
424
425 tfile->detached = NULL;
426 list_del_init(&tfile->next);
427 --tun->numdisabled;
428 return tun;
429}
430
431static void tun_queue_purge(struct tun_file *tfile)
432{
433 skb_queue_purge(&tfile->sk.sk_receive_queue);
434 skb_queue_purge(&tfile->sk.sk_error_queue);
435}
436
437static void __tun_detach(struct tun_file *tfile, bool clean)
438{
439 struct tun_file *ntfile;
440 struct tun_struct *tun;
441
442 tun = rtnl_dereference(tfile->tun);
443
444 if (tun && !tfile->detached) {
445 u16 index = tfile->queue_index;
446 BUG_ON(index >= tun->numqueues);
447
448 rcu_assign_pointer(tun->tfiles[index],
449 tun->tfiles[tun->numqueues - 1]);
450 ntfile = rtnl_dereference(tun->tfiles[index]);
451 ntfile->queue_index = index;
452
453 --tun->numqueues;
454 if (clean) {
455 RCU_INIT_POINTER(tfile->tun, NULL);
456 sock_put(&tfile->sk);
457 } else
458 tun_disable_queue(tun, tfile);
459
460 synchronize_net();
461 tun_flow_delete_by_queue(tun, tun->numqueues + 1);
462 /* Drop read queue */
463 tun_queue_purge(tfile);
464 tun_set_real_num_queues(tun);
465 } else if (tfile->detached && clean) {
466 tun = tun_enable_queue(tfile);
467 sock_put(&tfile->sk);
468 }
469
470 if (clean) {
471 if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
472 netif_carrier_off(tun->dev);
473
474 if (!(tun->flags & TUN_PERSIST) &&
475 tun->dev->reg_state == NETREG_REGISTERED)
476 unregister_netdevice(tun->dev);
477 }
478
479 BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED,
480 &tfile->socket.flags));
481 sk_release_kernel(&tfile->sk);
482 }
483}
484
485static void tun_detach(struct tun_file *tfile, bool clean)
486{
487 rtnl_lock();
488 __tun_detach(tfile, clean);
489 rtnl_unlock();
490}
491
492static void tun_detach_all(struct net_device *dev)
493{
494 struct tun_struct *tun = netdev_priv(dev);
495 struct tun_file *tfile, *tmp;
496 int i, n = tun->numqueues;
497
498 for (i = 0; i < n; i++) {
499 tfile = rtnl_dereference(tun->tfiles[i]);
500 BUG_ON(!tfile);
501 wake_up_all(&tfile->wq.wait);
502 RCU_INIT_POINTER(tfile->tun, NULL);
503 --tun->numqueues;
504 }
505 list_for_each_entry(tfile, &tun->disabled, next) {
506 wake_up_all(&tfile->wq.wait);
507 RCU_INIT_POINTER(tfile->tun, NULL);
508 }
509 BUG_ON(tun->numqueues != 0);
510
511 synchronize_net();
512 for (i = 0; i < n; i++) {
513 tfile = rtnl_dereference(tun->tfiles[i]);
514 /* Drop read queue */
515 tun_queue_purge(tfile);
516 sock_put(&tfile->sk);
517 }
518 list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
519 tun_enable_queue(tfile);
520 tun_queue_purge(tfile);
521 sock_put(&tfile->sk);
522 }
523 BUG_ON(tun->numdisabled != 0);
524
525 if (tun->flags & TUN_PERSIST)
526 module_put(THIS_MODULE);
527}
528
529static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter)
530{
531 struct tun_file *tfile = file->private_data;
532 int err;
533
534 err = security_tun_dev_attach(tfile->socket.sk, tun->security);
535 if (err < 0)
536 goto out;
537
538 err = -EINVAL;
539 if (rtnl_dereference(tfile->tun) && !tfile->detached)
540 goto out;
541
542 err = -EBUSY;
543 if (!(tun->flags & TUN_TAP_MQ) && tun->numqueues == 1)
544 goto out;
545
546 err = -E2BIG;
547 if (!tfile->detached &&
548 tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
549 goto out;
550
551 err = 0;
552
553 /* Re-attach the filter to persist device */
554 if (!skip_filter && (tun->filter_attached == true)) {
555 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
556 if (!err)
557 goto out;
558 }
559 tfile->queue_index = tun->numqueues;
560 rcu_assign_pointer(tfile->tun, tun);
561 rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
562 tun->numqueues++;
563
564 if (tfile->detached)
565 tun_enable_queue(tfile);
566 else
567 sock_hold(&tfile->sk);
568
569 tun_set_real_num_queues(tun);
570
571 /* device is allowed to go away first, so no need to hold extra
572 * refcnt.
573 */
574
575out:
576 return err;
577}
578
579static struct tun_struct *__tun_get(struct tun_file *tfile)
580{
581 struct tun_struct *tun;
582
583 rcu_read_lock();
584 tun = rcu_dereference(tfile->tun);
585 if (tun)
586 dev_hold(tun->dev);
587 rcu_read_unlock();
588
589 return tun;
590}
591
592static struct tun_struct *tun_get(struct file *file)
593{
594 return __tun_get(file->private_data);
595}
596
597static void tun_put(struct tun_struct *tun)
598{
599 dev_put(tun->dev);
600}
601
602/* TAP filtering */
603static void addr_hash_set(u32 *mask, const u8 *addr)
604{
605 int n = ether_crc(ETH_ALEN, addr) >> 26;
606 mask[n >> 5] |= (1 << (n & 31));
607}
608
609static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
610{
611 int n = ether_crc(ETH_ALEN, addr) >> 26;
612 return mask[n >> 5] & (1 << (n & 31));
613}
614
615static int update_filter(struct tap_filter *filter, void __user *arg)
616{
617 struct { u8 u[ETH_ALEN]; } *addr;
618 struct tun_filter uf;
619 int err, alen, n, nexact;
620
621 if (copy_from_user(&uf, arg, sizeof(uf)))
622 return -EFAULT;
623
624 if (!uf.count) {
625 /* Disabled */
626 filter->count = 0;
627 return 0;
628 }
629
630 alen = ETH_ALEN * uf.count;
631 addr = kmalloc(alen, GFP_KERNEL);
632 if (!addr)
633 return -ENOMEM;
634
635 if (copy_from_user(addr, arg + sizeof(uf), alen)) {
636 err = -EFAULT;
637 goto done;
638 }
639
640 /* The filter is updated without holding any locks. Which is
641 * perfectly safe. We disable it first and in the worst
642 * case we'll accept a few undesired packets. */
643 filter->count = 0;
644 wmb();
645
646 /* Use first set of addresses as an exact filter */
647 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
648 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
649
650 nexact = n;
651
652 /* Remaining multicast addresses are hashed,
653 * unicast will leave the filter disabled. */
654 memset(filter->mask, 0, sizeof(filter->mask));
655 for (; n < uf.count; n++) {
656 if (!is_multicast_ether_addr(addr[n].u)) {
657 err = 0; /* no filter */
658 goto done;
659 }
660 addr_hash_set(filter->mask, addr[n].u);
661 }
662
663 /* For ALLMULTI just set the mask to all ones.
664 * This overrides the mask populated above. */
665 if ((uf.flags & TUN_FLT_ALLMULTI))
666 memset(filter->mask, ~0, sizeof(filter->mask));
667
668 /* Now enable the filter */
669 wmb();
670 filter->count = nexact;
671
672 /* Return the number of exact filters */
673 err = nexact;
674
675done:
676 kfree(addr);
677 return err;
678}
679
680/* Returns: 0 - drop, !=0 - accept */
681static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
682{
683 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
684 * at this point. */
685 struct ethhdr *eh = (struct ethhdr *) skb->data;
686 int i;
687
688 /* Exact match */
689 for (i = 0; i < filter->count; i++)
690 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
691 return 1;
692
693 /* Inexact match (multicast only) */
694 if (is_multicast_ether_addr(eh->h_dest))
695 return addr_hash_test(filter->mask, eh->h_dest);
696
697 return 0;
698}
699
700/*
701 * Checks whether the packet is accepted or not.
702 * Returns: 0 - drop, !=0 - accept
703 */
704static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
705{
706 if (!filter->count)
707 return 1;
708
709 return run_filter(filter, skb);
710}
711
712/* Network device part of the driver */
713
714static const struct ethtool_ops tun_ethtool_ops;
715
716/* Net device detach from fd. */
717static void tun_net_uninit(struct net_device *dev)
718{
719 tun_detach_all(dev);
720}
721
722/* Net device open. */
723static int tun_net_open(struct net_device *dev)
724{
725 netif_tx_start_all_queues(dev);
726 return 0;
727}
728
729/* Net device close. */
730static int tun_net_close(struct net_device *dev)
731{
732 netif_tx_stop_all_queues(dev);
733 return 0;
734}
735
736/* Net device start xmit */
737static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
738{
739 struct tun_struct *tun = netdev_priv(dev);
740 int txq = skb->queue_mapping;
741 struct tun_file *tfile;
742 u32 numqueues = 0;
743
744 rcu_read_lock();
745 tfile = rcu_dereference(tun->tfiles[txq]);
746 numqueues = ACCESS_ONCE(tun->numqueues);
747
748 /* Drop packet if interface is not attached */
749 if (txq >= numqueues)
750 goto drop;
751
752 if (numqueues == 1) {
753 /* Select queue was not called for the skbuff, so we extract the
754 * RPS hash and save it into the flow_table here.
755 */
756 __u32 rxhash;
757
758 rxhash = skb_get_hash(skb);
759 if (rxhash) {
760 struct tun_flow_entry *e;
761 e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)],
762 rxhash);
763 if (e)
764 tun_flow_save_rps_rxhash(e, rxhash);
765 }
766 }
767
768 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
769
770 BUG_ON(!tfile);
771
772 /* Drop if the filter does not like it.
773 * This is a noop if the filter is disabled.
774 * Filter can be enabled only for the TAP devices. */
775 if (!check_filter(&tun->txflt, skb))
776 goto drop;
777
778 if (tfile->socket.sk->sk_filter &&
779 sk_filter(tfile->socket.sk, skb))
780 goto drop;
781
782 /* Limit the number of packets queued by dividing txq length with the
783 * number of queues.
784 */
785 if (skb_queue_len(&tfile->socket.sk->sk_receive_queue) * numqueues
786 >= dev->tx_queue_len)
787 goto drop;
788
789 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
790 goto drop;
791
792 if (skb->sk) {
793 sock_tx_timestamp(skb->sk, &skb_shinfo(skb)->tx_flags);
794 sw_tx_timestamp(skb);
795 }
796
797 /* Orphan the skb - required as we might hang on to it
798 * for indefinite time.
799 */
800 skb_orphan(skb);
801
802 nf_reset(skb);
803
804 /* Enqueue packet */
805 skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb);
806
807 /* Notify and wake up reader process */
808 if (tfile->flags & TUN_FASYNC)
809 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
810 wake_up_interruptible_poll(&tfile->wq.wait, POLLIN |
811 POLLRDNORM | POLLRDBAND);
812
813 rcu_read_unlock();
814 return NETDEV_TX_OK;
815
816drop:
817 dev->stats.tx_dropped++;
818 skb_tx_error(skb);
819 kfree_skb(skb);
820 rcu_read_unlock();
821 return NETDEV_TX_OK;
822}
823
824static void tun_net_mclist(struct net_device *dev)
825{
826 /*
827 * This callback is supposed to deal with mc filter in
828 * _rx_ path and has nothing to do with the _tx_ path.
829 * In rx path we always accept everything userspace gives us.
830 */
831}
832
833#define MIN_MTU 68
834#define MAX_MTU 65535
835
836static int
837tun_net_change_mtu(struct net_device *dev, int new_mtu)
838{
839 if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
840 return -EINVAL;
841 dev->mtu = new_mtu;
842 return 0;
843}
844
845static netdev_features_t tun_net_fix_features(struct net_device *dev,
846 netdev_features_t features)
847{
848 struct tun_struct *tun = netdev_priv(dev);
849
850 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
851}
852#ifdef CONFIG_NET_POLL_CONTROLLER
853static void tun_poll_controller(struct net_device *dev)
854{
855 /*
856 * Tun only receives frames when:
857 * 1) the char device endpoint gets data from user space
858 * 2) the tun socket gets a sendmsg call from user space
859 * Since both of those are synchronous operations, we are guaranteed
860 * never to have pending data when we poll for it
861 * so there is nothing to do here but return.
862 * We need this though so netpoll recognizes us as an interface that
863 * supports polling, which enables bridge devices in virt setups to
864 * still use netconsole
865 */
866 return;
867}
868#endif
869static const struct net_device_ops tun_netdev_ops = {
870 .ndo_uninit = tun_net_uninit,
871 .ndo_open = tun_net_open,
872 .ndo_stop = tun_net_close,
873 .ndo_start_xmit = tun_net_xmit,
874 .ndo_change_mtu = tun_net_change_mtu,
875 .ndo_fix_features = tun_net_fix_features,
876 .ndo_select_queue = tun_select_queue,
877#ifdef CONFIG_NET_POLL_CONTROLLER
878 .ndo_poll_controller = tun_poll_controller,
879#endif
880};
881
882static const struct net_device_ops tap_netdev_ops = {
883 .ndo_uninit = tun_net_uninit,
884 .ndo_open = tun_net_open,
885 .ndo_stop = tun_net_close,
886 .ndo_start_xmit = tun_net_xmit,
887 .ndo_change_mtu = tun_net_change_mtu,
888 .ndo_fix_features = tun_net_fix_features,
889 .ndo_set_rx_mode = tun_net_mclist,
890 .ndo_set_mac_address = eth_mac_addr,
891 .ndo_validate_addr = eth_validate_addr,
892 .ndo_select_queue = tun_select_queue,
893#ifdef CONFIG_NET_POLL_CONTROLLER
894 .ndo_poll_controller = tun_poll_controller,
895#endif
896};
897
898static void tun_flow_init(struct tun_struct *tun)
899{
900 int i;
901
902 for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
903 INIT_HLIST_HEAD(&tun->flows[i]);
904
905 tun->ageing_time = TUN_FLOW_EXPIRE;
906 setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun);
907 mod_timer(&tun->flow_gc_timer,
908 round_jiffies_up(jiffies + tun->ageing_time));
909}
910
911static void tun_flow_uninit(struct tun_struct *tun)
912{
913 del_timer_sync(&tun->flow_gc_timer);
914 tun_flow_flush(tun);
915}
916
917/* Initialize net device. */
918static void tun_net_init(struct net_device *dev)
919{
920 struct tun_struct *tun = netdev_priv(dev);
921
922 switch (tun->flags & TUN_TYPE_MASK) {
923 case TUN_TUN_DEV:
924 dev->netdev_ops = &tun_netdev_ops;
925
926 /* Point-to-Point TUN Device */
927 dev->hard_header_len = 0;
928 dev->addr_len = 0;
929 dev->mtu = 1500;
930
931 /* Zero header length */
932 dev->type = ARPHRD_NONE;
933 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
934 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */
935 break;
936
937 case TUN_TAP_DEV:
938 dev->netdev_ops = &tap_netdev_ops;
939 /* Ethernet TAP Device */
940 ether_setup(dev);
941 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
942 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
943
944 eth_hw_addr_random(dev);
945
946 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */
947 break;
948 }
949}
950
951/* Character device part */
952
953/* Poll */
954static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
955{
956 struct tun_file *tfile = file->private_data;
957 struct tun_struct *tun = __tun_get(tfile);
958 struct sock *sk;
959 unsigned int mask = 0;
960
961 if (!tun)
962 return POLLERR;
963
964 sk = tfile->socket.sk;
965
966 tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
967
968 poll_wait(file, &tfile->wq.wait, wait);
969
970 if (!skb_queue_empty(&sk->sk_receive_queue))
971 mask |= POLLIN | POLLRDNORM;
972
973 if (sock_writeable(sk) ||
974 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
975 sock_writeable(sk)))
976 mask |= POLLOUT | POLLWRNORM;
977
978 if (tun->dev->reg_state != NETREG_REGISTERED)
979 mask = POLLERR;
980
981 tun_put(tun);
982 return mask;
983}
984
985/* prepad is the amount to reserve at front. len is length after that.
986 * linear is a hint as to how much to copy (usually headers). */
987static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
988 size_t prepad, size_t len,
989 size_t linear, int noblock)
990{
991 struct sock *sk = tfile->socket.sk;
992 struct sk_buff *skb;
993 int err;
994
995 /* Under a page? Don't bother with paged skb. */
996 if (prepad + len < PAGE_SIZE || !linear)
997 linear = len;
998
999 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
1000 &err, 0);
1001 if (!skb)
1002 return ERR_PTR(err);
1003
1004 skb_reserve(skb, prepad);
1005 skb_put(skb, linear);
1006 skb->data_len = len - linear;
1007 skb->len += len - linear;
1008
1009 return skb;
1010}
1011
1012/* Get packet from user space buffer */
1013static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
1014 void *msg_control, const struct iovec *iv,
1015 size_t total_len, size_t count, int noblock)
1016{
1017 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
1018 struct sk_buff *skb;
1019 size_t len = total_len, align = NET_SKB_PAD, linear;
1020 struct virtio_net_hdr gso = { 0 };
1021 int good_linear;
1022 int offset = 0;
1023 int copylen;
1024 bool zerocopy = false;
1025 int err;
1026 u32 rxhash;
1027
1028 if (!(tun->flags & TUN_NO_PI)) {
1029 if (len < sizeof(pi))
1030 return -EINVAL;
1031 len -= sizeof(pi);
1032
1033 if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
1034 return -EFAULT;
1035 offset += sizeof(pi);
1036 }
1037
1038 if (tun->flags & TUN_VNET_HDR) {
1039 if (len < tun->vnet_hdr_sz)
1040 return -EINVAL;
1041 len -= tun->vnet_hdr_sz;
1042
1043 if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
1044 return -EFAULT;
1045
1046 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
1047 gso.csum_start + gso.csum_offset + 2 > gso.hdr_len)
1048 gso.hdr_len = gso.csum_start + gso.csum_offset + 2;
1049
1050 if (gso.hdr_len > len)
1051 return -EINVAL;
1052 offset += tun->vnet_hdr_sz;
1053 }
1054
1055 if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
1056 align += NET_IP_ALIGN;
1057 if (unlikely(len < ETH_HLEN ||
1058 (gso.hdr_len && gso.hdr_len < ETH_HLEN)))
1059 return -EINVAL;
1060 }
1061
1062 good_linear = SKB_MAX_HEAD(align);
1063
1064 if (msg_control) {
1065 /* There are 256 bytes to be copied in skb, so there is
1066 * enough room for skb expand head in case it is used.
1067 * The rest of the buffer is mapped from userspace.
1068 */
1069 copylen = gso.hdr_len ? gso.hdr_len : GOODCOPY_LEN;
1070 if (copylen > good_linear)
1071 copylen = good_linear;
1072 linear = copylen;
1073 if (iov_pages(iv, offset + copylen, count) <= MAX_SKB_FRAGS)
1074 zerocopy = true;
1075 }
1076
1077 if (!zerocopy) {
1078 copylen = len;
1079 if (gso.hdr_len > good_linear)
1080 linear = good_linear;
1081 else
1082 linear = gso.hdr_len;
1083 }
1084
1085 skb = tun_alloc_skb(tfile, align, copylen, linear, noblock);
1086 if (IS_ERR(skb)) {
1087 if (PTR_ERR(skb) != -EAGAIN)
1088 tun->dev->stats.rx_dropped++;
1089 return PTR_ERR(skb);
1090 }
1091
1092 if (zerocopy)
1093 err = zerocopy_sg_from_iovec(skb, iv, offset, count);
1094 else {
1095 err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len);
1096 if (!err && msg_control) {
1097 struct ubuf_info *uarg = msg_control;
1098 uarg->callback(uarg, false);
1099 }
1100 }
1101
1102 if (err) {
1103 tun->dev->stats.rx_dropped++;
1104 kfree_skb(skb);
1105 return -EFAULT;
1106 }
1107
1108 if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
1109 if (!skb_partial_csum_set(skb, gso.csum_start,
1110 gso.csum_offset)) {
1111 tun->dev->stats.rx_frame_errors++;
1112 kfree_skb(skb);
1113 return -EINVAL;
1114 }
1115 }
1116
1117 switch (tun->flags & TUN_TYPE_MASK) {
1118 case TUN_TUN_DEV:
1119 if (tun->flags & TUN_NO_PI) {
1120 switch (skb->data[0] & 0xf0) {
1121 case 0x40:
1122 pi.proto = htons(ETH_P_IP);
1123 break;
1124 case 0x60:
1125 pi.proto = htons(ETH_P_IPV6);
1126 break;
1127 default:
1128 tun->dev->stats.rx_dropped++;
1129 kfree_skb(skb);
1130 return -EINVAL;
1131 }
1132 }
1133
1134 skb_reset_mac_header(skb);
1135 skb->protocol = pi.proto;
1136 skb->dev = tun->dev;
1137 break;
1138 case TUN_TAP_DEV:
1139 skb->protocol = eth_type_trans(skb, tun->dev);
1140 break;
1141 }
1142
1143 if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
1144 pr_debug("GSO!\n");
1145 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
1146 case VIRTIO_NET_HDR_GSO_TCPV4:
1147 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1148 break;
1149 case VIRTIO_NET_HDR_GSO_TCPV6:
1150 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
1151 break;
1152 case VIRTIO_NET_HDR_GSO_UDP:
1153 skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1154 break;
1155 default:
1156 tun->dev->stats.rx_frame_errors++;
1157 kfree_skb(skb);
1158 return -EINVAL;
1159 }
1160
1161 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
1162 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
1163
1164 skb_shinfo(skb)->gso_size = gso.gso_size;
1165 if (skb_shinfo(skb)->gso_size == 0) {
1166 tun->dev->stats.rx_frame_errors++;
1167 kfree_skb(skb);
1168 return -EINVAL;
1169 }
1170
1171 /* Header must be checked, and gso_segs computed. */
1172 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
1173 skb_shinfo(skb)->gso_segs = 0;
1174 }
1175
1176 /* copy skb_ubuf_info for callback when skb has no error */
1177 if (zerocopy) {
1178 skb_shinfo(skb)->destructor_arg = msg_control;
1179 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
1180 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1181 }
1182
1183 skb_reset_network_header(skb);
1184 skb_probe_transport_header(skb, 0);
1185
1186 rxhash = skb_get_hash(skb);
1187 netif_rx_ni(skb);
1188
1189 tun->dev->stats.rx_packets++;
1190 tun->dev->stats.rx_bytes += len;
1191
1192 tun_flow_update(tun, rxhash, tfile);
1193 return total_len;
1194}
1195
1196static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
1197 unsigned long count, loff_t pos)
1198{
1199 struct file *file = iocb->ki_filp;
1200 struct tun_struct *tun = tun_get(file);
1201 struct tun_file *tfile = file->private_data;
1202 ssize_t result;
1203
1204 if (!tun)
1205 return -EBADFD;
1206
1207 tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count);
1208
1209 result = tun_get_user(tun, tfile, NULL, iv, iov_length(iv, count),
1210 count, file->f_flags & O_NONBLOCK);
1211
1212 tun_put(tun);
1213 return result;
1214}
1215
1216/* Put packet to the user space buffer */
1217static ssize_t tun_put_user(struct tun_struct *tun,
1218 struct tun_file *tfile,
1219 struct sk_buff *skb,
1220 const struct iovec *iv, int len)
1221{
1222 struct tun_pi pi = { 0, skb->protocol };
1223 ssize_t total = 0;
1224 int vlan_offset = 0, copied;
1225
1226 if (!(tun->flags & TUN_NO_PI)) {
1227 if ((len -= sizeof(pi)) < 0)
1228 return -EINVAL;
1229
1230 if (len < skb->len) {
1231 /* Packet will be striped */
1232 pi.flags |= TUN_PKT_STRIP;
1233 }
1234
1235 if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi)))
1236 return -EFAULT;
1237 total += sizeof(pi);
1238 }
1239
1240 if (tun->flags & TUN_VNET_HDR) {
1241 struct virtio_net_hdr gso = { 0 }; /* no info leak */
1242 if ((len -= tun->vnet_hdr_sz) < 0)
1243 return -EINVAL;
1244
1245 if (skb_is_gso(skb)) {
1246 struct skb_shared_info *sinfo = skb_shinfo(skb);
1247
1248 /* This is a hint as to how much should be linear. */
1249 gso.hdr_len = skb_headlen(skb);
1250 gso.gso_size = sinfo->gso_size;
1251 if (sinfo->gso_type & SKB_GSO_TCPV4)
1252 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
1253 else if (sinfo->gso_type & SKB_GSO_TCPV6)
1254 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
1255 else if (sinfo->gso_type & SKB_GSO_UDP)
1256 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
1257 else {
1258 pr_err("unexpected GSO type: "
1259 "0x%x, gso_size %d, hdr_len %d\n",
1260 sinfo->gso_type, gso.gso_size,
1261 gso.hdr_len);
1262 print_hex_dump(KERN_ERR, "tun: ",
1263 DUMP_PREFIX_NONE,
1264 16, 1, skb->head,
1265 min((int)gso.hdr_len, 64), true);
1266 WARN_ON_ONCE(1);
1267 return -EINVAL;
1268 }
1269 if (sinfo->gso_type & SKB_GSO_TCP_ECN)
1270 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
1271 } else
1272 gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
1273
1274 if (skb->ip_summed == CHECKSUM_PARTIAL) {
1275 gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
1276 gso.csum_start = skb_checksum_start_offset(skb);
1277 gso.csum_offset = skb->csum_offset;
1278 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
1279 gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
1280 } /* else everything is zero */
1281
1282 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total,
1283 sizeof(gso))))
1284 return -EFAULT;
1285 total += tun->vnet_hdr_sz;
1286 }
1287
1288 copied = total;
1289 total += skb->len;
1290 if (!vlan_tx_tag_present(skb)) {
1291 len = min_t(int, skb->len, len);
1292 } else {
1293 int copy, ret;
1294 struct {
1295 __be16 h_vlan_proto;
1296 __be16 h_vlan_TCI;
1297 } veth;
1298
1299 veth.h_vlan_proto = skb->vlan_proto;
1300 veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb));
1301
1302 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
1303 len = min_t(int, skb->len + VLAN_HLEN, len);
1304 total += VLAN_HLEN;
1305
1306 copy = min_t(int, vlan_offset, len);
1307 ret = skb_copy_datagram_const_iovec(skb, 0, iv, copied, copy);
1308 len -= copy;
1309 copied += copy;
1310 if (ret || !len)
1311 goto done;
1312
1313 copy = min_t(int, sizeof(veth), len);
1314 ret = memcpy_toiovecend(iv, (void *)&veth, copied, copy);
1315 len -= copy;
1316 copied += copy;
1317 if (ret || !len)
1318 goto done;
1319 }
1320
1321 skb_copy_datagram_const_iovec(skb, vlan_offset, iv, copied, len);
1322
1323done:
1324 tun->dev->stats.tx_packets++;
1325 tun->dev->stats.tx_bytes += len;
1326
1327 return total;
1328}
1329
1330static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
1331 const struct iovec *iv, ssize_t len, int noblock)
1332{
1333 DECLARE_WAITQUEUE(wait, current);
1334 struct sk_buff *skb;
1335 ssize_t ret = 0;
1336
1337 tun_debug(KERN_INFO, tun, "tun_do_read\n");
1338
1339 if (unlikely(!noblock))
1340 add_wait_queue(&tfile->wq.wait, &wait);
1341 while (len) {
1342 if (unlikely(!noblock))
1343 current->state = TASK_INTERRUPTIBLE;
1344
1345 /* Read frames from the queue */
1346 if (!(skb = skb_dequeue(&tfile->socket.sk->sk_receive_queue))) {
1347 if (noblock) {
1348 ret = -EAGAIN;
1349 break;
1350 }
1351 if (signal_pending(current)) {
1352 ret = -ERESTARTSYS;
1353 break;
1354 }
1355 if (tun->dev->reg_state != NETREG_REGISTERED) {
1356 ret = -EIO;
1357 break;
1358 }
1359
1360 /* Nothing to read, let's sleep */
1361 schedule();
1362 continue;
1363 }
1364
1365 ret = tun_put_user(tun, tfile, skb, iv, len);
1366 kfree_skb(skb);
1367 break;
1368 }
1369
1370 if (unlikely(!noblock)) {
1371 current->state = TASK_RUNNING;
1372 remove_wait_queue(&tfile->wq.wait, &wait);
1373 }
1374
1375 return ret;
1376}
1377
1378static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
1379 unsigned long count, loff_t pos)
1380{
1381 struct file *file = iocb->ki_filp;
1382 struct tun_file *tfile = file->private_data;
1383 struct tun_struct *tun = __tun_get(tfile);
1384 ssize_t len, ret;
1385
1386 if (!tun)
1387 return -EBADFD;
1388 len = iov_length(iv, count);
1389 if (len < 0) {
1390 ret = -EINVAL;
1391 goto out;
1392 }
1393
1394 ret = tun_do_read(tun, tfile, iv, len,
1395 file->f_flags & O_NONBLOCK);
1396 ret = min_t(ssize_t, ret, len);
1397 if (ret > 0)
1398 iocb->ki_pos = ret;
1399out:
1400 tun_put(tun);
1401 return ret;
1402}
1403
1404static void tun_free_netdev(struct net_device *dev)
1405{
1406 struct tun_struct *tun = netdev_priv(dev);
1407
1408 BUG_ON(!(list_empty(&tun->disabled)));
1409 tun_flow_uninit(tun);
1410 security_tun_dev_free_security(tun->security);
1411 free_netdev(dev);
1412}
1413
1414static void tun_setup(struct net_device *dev)
1415{
1416 struct tun_struct *tun = netdev_priv(dev);
1417
1418 tun->owner = INVALID_UID;
1419 tun->group = INVALID_GID;
1420
1421 dev->ethtool_ops = &tun_ethtool_ops;
1422 dev->destructor = tun_free_netdev;
1423}
1424
1425/* Trivial set of netlink ops to allow deleting tun or tap
1426 * device with netlink.
1427 */
1428static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
1429{
1430 return -EINVAL;
1431}
1432
1433static struct rtnl_link_ops tun_link_ops __read_mostly = {
1434 .kind = DRV_NAME,
1435 .priv_size = sizeof(struct tun_struct),
1436 .setup = tun_setup,
1437 .validate = tun_validate,
1438};
1439
1440static void tun_sock_write_space(struct sock *sk)
1441{
1442 struct tun_file *tfile;
1443 wait_queue_head_t *wqueue;
1444
1445 if (!sock_writeable(sk))
1446 return;
1447
1448 if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
1449 return;
1450
1451 wqueue = sk_sleep(sk);
1452 if (wqueue && waitqueue_active(wqueue))
1453 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1454 POLLWRNORM | POLLWRBAND);
1455
1456 tfile = container_of(sk, struct tun_file, sk);
1457 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
1458}
1459
1460static int tun_sendmsg(struct kiocb *iocb, struct socket *sock,
1461 struct msghdr *m, size_t total_len)
1462{
1463 int ret;
1464 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1465 struct tun_struct *tun = __tun_get(tfile);
1466
1467 if (!tun)
1468 return -EBADFD;
1469 ret = tun_get_user(tun, tfile, m->msg_control, m->msg_iov, total_len,
1470 m->msg_iovlen, m->msg_flags & MSG_DONTWAIT);
1471 tun_put(tun);
1472 return ret;
1473}
1474
1475static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
1476 struct msghdr *m, size_t total_len,
1477 int flags)
1478{
1479 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1480 struct tun_struct *tun = __tun_get(tfile);
1481 int ret;
1482
1483 if (!tun)
1484 return -EBADFD;
1485
1486 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
1487 ret = -EINVAL;
1488 goto out;
1489 }
1490 if (flags & MSG_ERRQUEUE) {
1491 ret = sock_recv_errqueue(sock->sk, m, total_len,
1492 SOL_PACKET, TUN_TX_TIMESTAMP);
1493 goto out;
1494 }
1495 ret = tun_do_read(tun, tfile, m->msg_iov, total_len,
1496 flags & MSG_DONTWAIT);
1497 if (ret > total_len) {
1498 m->msg_flags |= MSG_TRUNC;
1499 ret = flags & MSG_TRUNC ? ret : total_len;
1500 }
1501out:
1502 tun_put(tun);
1503 return ret;
1504}
1505
1506static int tun_release(struct socket *sock)
1507{
1508 if (sock->sk)
1509 sock_put(sock->sk);
1510 return 0;
1511}
1512
1513/* Ops structure to mimic raw sockets with tun */
1514static const struct proto_ops tun_socket_ops = {
1515 .sendmsg = tun_sendmsg,
1516 .recvmsg = tun_recvmsg,
1517 .release = tun_release,
1518};
1519
1520static struct proto tun_proto = {
1521 .name = "tun",
1522 .owner = THIS_MODULE,
1523 .obj_size = sizeof(struct tun_file),
1524};
1525
1526static int tun_flags(struct tun_struct *tun)
1527{
1528 int flags = 0;
1529
1530 if (tun->flags & TUN_TUN_DEV)
1531 flags |= IFF_TUN;
1532 else
1533 flags |= IFF_TAP;
1534
1535 if (tun->flags & TUN_NO_PI)
1536 flags |= IFF_NO_PI;
1537
1538 /* This flag has no real effect. We track the value for backwards
1539 * compatibility.
1540 */
1541 if (tun->flags & TUN_ONE_QUEUE)
1542 flags |= IFF_ONE_QUEUE;
1543
1544 if (tun->flags & TUN_VNET_HDR)
1545 flags |= IFF_VNET_HDR;
1546
1547 if (tun->flags & TUN_TAP_MQ)
1548 flags |= IFF_MULTI_QUEUE;
1549
1550 if (tun->flags & TUN_PERSIST)
1551 flags |= IFF_PERSIST;
1552
1553 return flags;
1554}
1555
1556static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1557 char *buf)
1558{
1559 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1560 return sprintf(buf, "0x%x\n", tun_flags(tun));
1561}
1562
1563static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1564 char *buf)
1565{
1566 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1567 return uid_valid(tun->owner)?
1568 sprintf(buf, "%u\n",
1569 from_kuid_munged(current_user_ns(), tun->owner)):
1570 sprintf(buf, "-1\n");
1571}
1572
1573static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1574 char *buf)
1575{
1576 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1577 return gid_valid(tun->group) ?
1578 sprintf(buf, "%u\n",
1579 from_kgid_munged(current_user_ns(), tun->group)):
1580 sprintf(buf, "-1\n");
1581}
1582
1583static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1584static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1585static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1586
1587static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1588{
1589 struct tun_struct *tun;
1590 struct tun_file *tfile = file->private_data;
1591 struct net_device *dev;
1592 int err;
1593
1594 if (tfile->detached)
1595 return -EINVAL;
1596
1597 dev = __dev_get_by_name(net, ifr->ifr_name);
1598 if (dev) {
1599 if (ifr->ifr_flags & IFF_TUN_EXCL)
1600 return -EBUSY;
1601 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1602 tun = netdev_priv(dev);
1603 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1604 tun = netdev_priv(dev);
1605 else
1606 return -EINVAL;
1607
1608 if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
1609 !!(tun->flags & TUN_TAP_MQ))
1610 return -EINVAL;
1611
1612 if (tun_not_capable(tun))
1613 return -EPERM;
1614 err = security_tun_dev_open(tun->security);
1615 if (err < 0)
1616 return err;
1617
1618 err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER);
1619 if (err < 0)
1620 return err;
1621
1622 if (tun->flags & TUN_TAP_MQ &&
1623 (tun->numqueues + tun->numdisabled > 1)) {
1624 /* One or more queue has already been attached, no need
1625 * to initialize the device again.
1626 */
1627 return 0;
1628 }
1629 }
1630 else {
1631 char *name;
1632 unsigned long flags = 0;
1633 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
1634 MAX_TAP_QUEUES : 1;
1635
1636 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1637 return -EPERM;
1638 err = security_tun_dev_create();
1639 if (err < 0)
1640 return err;
1641
1642 /* Set dev type */
1643 if (ifr->ifr_flags & IFF_TUN) {
1644 /* TUN device */
1645 flags |= TUN_TUN_DEV;
1646 name = "tun%d";
1647 } else if (ifr->ifr_flags & IFF_TAP) {
1648 /* TAP device */
1649 flags |= TUN_TAP_DEV;
1650 name = "tap%d";
1651 } else
1652 return -EINVAL;
1653
1654 if (*ifr->ifr_name)
1655 name = ifr->ifr_name;
1656
1657 dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
1658 tun_setup, queues, queues);
1659
1660 if (!dev)
1661 return -ENOMEM;
1662
1663 dev_net_set(dev, net);
1664 dev->rtnl_link_ops = &tun_link_ops;
1665 dev->ifindex = tfile->ifindex;
1666
1667 tun = netdev_priv(dev);
1668 tun->dev = dev;
1669 tun->flags = flags;
1670 tun->txflt.count = 0;
1671 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1672
1673 tun->filter_attached = false;
1674 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
1675
1676 spin_lock_init(&tun->lock);
1677
1678 err = security_tun_dev_alloc_security(&tun->security);
1679 if (err < 0)
1680 goto err_free_dev;
1681
1682 tun_net_init(dev);
1683 tun_flow_init(tun);
1684
1685 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1686 TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
1687 NETIF_F_HW_VLAN_STAG_TX;
1688 dev->features = dev->hw_features;
1689 dev->vlan_features = dev->features &
1690 ~(NETIF_F_HW_VLAN_CTAG_TX |
1691 NETIF_F_HW_VLAN_STAG_TX);
1692
1693 INIT_LIST_HEAD(&tun->disabled);
1694 err = tun_attach(tun, file, false);
1695 if (err < 0)
1696 goto err_free_flow;
1697
1698 err = register_netdevice(tun->dev);
1699 if (err < 0)
1700 goto err_detach;
1701
1702 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) ||
1703 device_create_file(&tun->dev->dev, &dev_attr_owner) ||
1704 device_create_file(&tun->dev->dev, &dev_attr_group))
1705 pr_err("Failed to create tun sysfs files\n");
1706 }
1707
1708 netif_carrier_on(tun->dev);
1709
1710 tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1711
1712 if (ifr->ifr_flags & IFF_NO_PI)
1713 tun->flags |= TUN_NO_PI;
1714 else
1715 tun->flags &= ~TUN_NO_PI;
1716
1717 /* This flag has no real effect. We track the value for backwards
1718 * compatibility.
1719 */
1720 if (ifr->ifr_flags & IFF_ONE_QUEUE)
1721 tun->flags |= TUN_ONE_QUEUE;
1722 else
1723 tun->flags &= ~TUN_ONE_QUEUE;
1724
1725 if (ifr->ifr_flags & IFF_VNET_HDR)
1726 tun->flags |= TUN_VNET_HDR;
1727 else
1728 tun->flags &= ~TUN_VNET_HDR;
1729
1730 if (ifr->ifr_flags & IFF_MULTI_QUEUE)
1731 tun->flags |= TUN_TAP_MQ;
1732 else
1733 tun->flags &= ~TUN_TAP_MQ;
1734
1735 /* Make sure persistent devices do not get stuck in
1736 * xoff state.
1737 */
1738 if (netif_running(tun->dev))
1739 netif_tx_wake_all_queues(tun->dev);
1740
1741 strcpy(ifr->ifr_name, tun->dev->name);
1742 return 0;
1743
1744err_detach:
1745 tun_detach_all(dev);
1746err_free_flow:
1747 tun_flow_uninit(tun);
1748 security_tun_dev_free_security(tun->security);
1749err_free_dev:
1750 free_netdev(dev);
1751 return err;
1752}
1753
1754static void tun_get_iff(struct net *net, struct tun_struct *tun,
1755 struct ifreq *ifr)
1756{
1757 tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1758
1759 strcpy(ifr->ifr_name, tun->dev->name);
1760
1761 ifr->ifr_flags = tun_flags(tun);
1762
1763}
1764
1765/* This is like a cut-down ethtool ops, except done via tun fd so no
1766 * privs required. */
1767static int set_offload(struct tun_struct *tun, unsigned long arg)
1768{
1769 netdev_features_t features = 0;
1770
1771 if (arg & TUN_F_CSUM) {
1772 features |= NETIF_F_HW_CSUM;
1773 arg &= ~TUN_F_CSUM;
1774
1775 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1776 if (arg & TUN_F_TSO_ECN) {
1777 features |= NETIF_F_TSO_ECN;
1778 arg &= ~TUN_F_TSO_ECN;
1779 }
1780 if (arg & TUN_F_TSO4)
1781 features |= NETIF_F_TSO;
1782 if (arg & TUN_F_TSO6)
1783 features |= NETIF_F_TSO6;
1784 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1785 }
1786
1787 if (arg & TUN_F_UFO) {
1788 features |= NETIF_F_UFO;
1789 arg &= ~TUN_F_UFO;
1790 }
1791 }
1792
1793 /* This gives the user a way to test for new features in future by
1794 * trying to set them. */
1795 if (arg)
1796 return -EINVAL;
1797
1798 tun->set_features = features;
1799 netdev_update_features(tun->dev);
1800
1801 return 0;
1802}
1803
1804static void tun_detach_filter(struct tun_struct *tun, int n)
1805{
1806 int i;
1807 struct tun_file *tfile;
1808
1809 for (i = 0; i < n; i++) {
1810 tfile = rtnl_dereference(tun->tfiles[i]);
1811 sk_detach_filter(tfile->socket.sk);
1812 }
1813
1814 tun->filter_attached = false;
1815}
1816
1817static int tun_attach_filter(struct tun_struct *tun)
1818{
1819 int i, ret = 0;
1820 struct tun_file *tfile;
1821
1822 for (i = 0; i < tun->numqueues; i++) {
1823 tfile = rtnl_dereference(tun->tfiles[i]);
1824 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
1825 if (ret) {
1826 tun_detach_filter(tun, i);
1827 return ret;
1828 }
1829 }
1830
1831 tun->filter_attached = true;
1832 return ret;
1833}
1834
1835static void tun_set_sndbuf(struct tun_struct *tun)
1836{
1837 struct tun_file *tfile;
1838 int i;
1839
1840 for (i = 0; i < tun->numqueues; i++) {
1841 tfile = rtnl_dereference(tun->tfiles[i]);
1842 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
1843 }
1844}
1845
1846static int tun_set_queue(struct file *file, struct ifreq *ifr)
1847{
1848 struct tun_file *tfile = file->private_data;
1849 struct tun_struct *tun;
1850 int ret = 0;
1851
1852 rtnl_lock();
1853
1854 if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
1855 tun = tfile->detached;
1856 if (!tun) {
1857 ret = -EINVAL;
1858 goto unlock;
1859 }
1860 ret = security_tun_dev_attach_queue(tun->security);
1861 if (ret < 0)
1862 goto unlock;
1863 ret = tun_attach(tun, file, false);
1864 } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
1865 tun = rtnl_dereference(tfile->tun);
1866 if (!tun || !(tun->flags & TUN_TAP_MQ) || tfile->detached)
1867 ret = -EINVAL;
1868 else
1869 __tun_detach(tfile, false);
1870 } else
1871 ret = -EINVAL;
1872
1873unlock:
1874 rtnl_unlock();
1875 return ret;
1876}
1877
1878static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1879 unsigned long arg, int ifreq_len)
1880{
1881 struct tun_file *tfile = file->private_data;
1882 struct tun_struct *tun;
1883 void __user* argp = (void __user*)arg;
1884 struct ifreq ifr;
1885 kuid_t owner;
1886 kgid_t group;
1887 int sndbuf;
1888 int vnet_hdr_sz;
1889 unsigned int ifindex;
1890 int ret;
1891
1892 if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) {
1893 if (copy_from_user(&ifr, argp, ifreq_len))
1894 return -EFAULT;
1895 } else {
1896 memset(&ifr, 0, sizeof(ifr));
1897 }
1898 if (cmd == TUNGETFEATURES) {
1899 /* Currently this just means: "what IFF flags are valid?".
1900 * This is needed because we never checked for invalid flags on
1901 * TUNSETIFF. */
1902 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
1903 IFF_VNET_HDR | IFF_MULTI_QUEUE,
1904 (unsigned int __user*)argp);
1905 } else if (cmd == TUNSETQUEUE)
1906 return tun_set_queue(file, &ifr);
1907
1908 ret = 0;
1909 rtnl_lock();
1910
1911 tun = __tun_get(tfile);
1912 if (cmd == TUNSETIFF && !tun) {
1913 ifr.ifr_name[IFNAMSIZ-1] = '\0';
1914
1915 ret = tun_set_iff(tfile->net, file, &ifr);
1916
1917 if (ret)
1918 goto unlock;
1919
1920 if (copy_to_user(argp, &ifr, ifreq_len))
1921 ret = -EFAULT;
1922 goto unlock;
1923 }
1924 if (cmd == TUNSETIFINDEX) {
1925 ret = -EPERM;
1926 if (tun)
1927 goto unlock;
1928
1929 ret = -EFAULT;
1930 if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
1931 goto unlock;
1932
1933 ret = 0;
1934 tfile->ifindex = ifindex;
1935 goto unlock;
1936 }
1937
1938 ret = -EBADFD;
1939 if (!tun)
1940 goto unlock;
1941
1942 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
1943
1944 ret = 0;
1945 switch (cmd) {
1946 case TUNGETIFF:
1947 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1948
1949 if (tfile->detached)
1950 ifr.ifr_flags |= IFF_DETACH_QUEUE;
1951 if (!tfile->socket.sk->sk_filter)
1952 ifr.ifr_flags |= IFF_NOFILTER;
1953
1954 if (copy_to_user(argp, &ifr, ifreq_len))
1955 ret = -EFAULT;
1956 break;
1957
1958 case TUNSETNOCSUM:
1959 /* Disable/Enable checksum */
1960
1961 /* [unimplemented] */
1962 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
1963 arg ? "disabled" : "enabled");
1964 break;
1965
1966 case TUNSETPERSIST:
1967 /* Disable/Enable persist mode. Keep an extra reference to the
1968 * module to prevent the module being unprobed.
1969 */
1970 if (arg && !(tun->flags & TUN_PERSIST)) {
1971 tun->flags |= TUN_PERSIST;
1972 __module_get(THIS_MODULE);
1973 }
1974 if (!arg && (tun->flags & TUN_PERSIST)) {
1975 tun->flags &= ~TUN_PERSIST;
1976 module_put(THIS_MODULE);
1977 }
1978
1979 tun_debug(KERN_INFO, tun, "persist %s\n",
1980 arg ? "enabled" : "disabled");
1981 break;
1982
1983 case TUNSETOWNER:
1984 /* Set owner of the device */
1985 owner = make_kuid(current_user_ns(), arg);
1986 if (!uid_valid(owner)) {
1987 ret = -EINVAL;
1988 break;
1989 }
1990 tun->owner = owner;
1991 tun_debug(KERN_INFO, tun, "owner set to %u\n",
1992 from_kuid(&init_user_ns, tun->owner));
1993 break;
1994
1995 case TUNSETGROUP:
1996 /* Set group of the device */
1997 group = make_kgid(current_user_ns(), arg);
1998 if (!gid_valid(group)) {
1999 ret = -EINVAL;
2000 break;
2001 }
2002 tun->group = group;
2003 tun_debug(KERN_INFO, tun, "group set to %u\n",
2004 from_kgid(&init_user_ns, tun->group));
2005 break;
2006
2007 case TUNSETLINK:
2008 /* Only allow setting the type when the interface is down */
2009 if (tun->dev->flags & IFF_UP) {
2010 tun_debug(KERN_INFO, tun,
2011 "Linktype set failed because interface is up\n");
2012 ret = -EBUSY;
2013 } else {
2014 tun->dev->type = (int) arg;
2015 tun_debug(KERN_INFO, tun, "linktype set to %d\n",
2016 tun->dev->type);
2017 ret = 0;
2018 }
2019 break;
2020
2021#ifdef TUN_DEBUG
2022 case TUNSETDEBUG:
2023 tun->debug = arg;
2024 break;
2025#endif
2026 case TUNSETOFFLOAD:
2027 ret = set_offload(tun, arg);
2028 break;
2029
2030 case TUNSETTXFILTER:
2031 /* Can be set only for TAPs */
2032 ret = -EINVAL;
2033 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
2034 break;
2035 ret = update_filter(&tun->txflt, (void __user *)arg);
2036 break;
2037
2038 case SIOCGIFHWADDR:
2039 /* Get hw address */
2040 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
2041 ifr.ifr_hwaddr.sa_family = tun->dev->type;
2042 if (copy_to_user(argp, &ifr, ifreq_len))
2043 ret = -EFAULT;
2044 break;
2045
2046 case SIOCSIFHWADDR:
2047 /* Set hw address */
2048 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
2049 ifr.ifr_hwaddr.sa_data);
2050
2051 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
2052 break;
2053
2054 case TUNGETSNDBUF:
2055 sndbuf = tfile->socket.sk->sk_sndbuf;
2056 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
2057 ret = -EFAULT;
2058 break;
2059
2060 case TUNSETSNDBUF:
2061 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
2062 ret = -EFAULT;
2063 break;
2064 }
2065
2066 tun->sndbuf = sndbuf;
2067 tun_set_sndbuf(tun);
2068 break;
2069
2070 case TUNGETVNETHDRSZ:
2071 vnet_hdr_sz = tun->vnet_hdr_sz;
2072 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
2073 ret = -EFAULT;
2074 break;
2075
2076 case TUNSETVNETHDRSZ:
2077 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
2078 ret = -EFAULT;
2079 break;
2080 }
2081 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
2082 ret = -EINVAL;
2083 break;
2084 }
2085
2086 tun->vnet_hdr_sz = vnet_hdr_sz;
2087 break;
2088
2089 case TUNATTACHFILTER:
2090 /* Can be set only for TAPs */
2091 ret = -EINVAL;
2092 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
2093 break;
2094 ret = -EFAULT;
2095 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
2096 break;
2097
2098 ret = tun_attach_filter(tun);
2099 break;
2100
2101 case TUNDETACHFILTER:
2102 /* Can be set only for TAPs */
2103 ret = -EINVAL;
2104 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
2105 break;
2106 ret = 0;
2107 tun_detach_filter(tun, tun->numqueues);
2108 break;
2109
2110 case TUNGETFILTER:
2111 ret = -EINVAL;
2112 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
2113 break;
2114 ret = -EFAULT;
2115 if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
2116 break;
2117 ret = 0;
2118 break;
2119
2120 default:
2121 ret = -EINVAL;
2122 break;
2123 }
2124
2125unlock:
2126 rtnl_unlock();
2127 if (tun)
2128 tun_put(tun);
2129 return ret;
2130}
2131
2132static long tun_chr_ioctl(struct file *file,
2133 unsigned int cmd, unsigned long arg)
2134{
2135 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
2136}
2137
2138#ifdef CONFIG_COMPAT
2139static long tun_chr_compat_ioctl(struct file *file,
2140 unsigned int cmd, unsigned long arg)
2141{
2142 switch (cmd) {
2143 case TUNSETIFF:
2144 case TUNGETIFF:
2145 case TUNSETTXFILTER:
2146 case TUNGETSNDBUF:
2147 case TUNSETSNDBUF:
2148 case SIOCGIFHWADDR:
2149 case SIOCSIFHWADDR:
2150 arg = (unsigned long)compat_ptr(arg);
2151 break;
2152 default:
2153 arg = (compat_ulong_t)arg;
2154 break;
2155 }
2156
2157 /*
2158 * compat_ifreq is shorter than ifreq, so we must not access beyond
2159 * the end of that structure. All fields that are used in this
2160 * driver are compatible though, we don't need to convert the
2161 * contents.
2162 */
2163 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
2164}
2165#endif /* CONFIG_COMPAT */
2166
2167static int tun_chr_fasync(int fd, struct file *file, int on)
2168{
2169 struct tun_file *tfile = file->private_data;
2170 int ret;
2171
2172 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
2173 goto out;
2174
2175 if (on) {
2176 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
2177 if (ret)
2178 goto out;
2179 tfile->flags |= TUN_FASYNC;
2180 } else
2181 tfile->flags &= ~TUN_FASYNC;
2182 ret = 0;
2183out:
2184 return ret;
2185}
2186
2187static int tun_chr_open(struct inode *inode, struct file * file)
2188{
2189 struct tun_file *tfile;
2190
2191 DBG1(KERN_INFO, "tunX: tun_chr_open\n");
2192
2193 tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL,
2194 &tun_proto);
2195 if (!tfile)
2196 return -ENOMEM;
2197 RCU_INIT_POINTER(tfile->tun, NULL);
2198 tfile->net = get_net(current->nsproxy->net_ns);
2199 tfile->flags = 0;
2200 tfile->ifindex = 0;
2201
2202 rcu_assign_pointer(tfile->socket.wq, &tfile->wq);
2203 init_waitqueue_head(&tfile->wq.wait);
2204
2205 tfile->socket.file = file;
2206 tfile->socket.ops = &tun_socket_ops;
2207
2208 sock_init_data(&tfile->socket, &tfile->sk);
2209 sk_change_net(&tfile->sk, tfile->net);
2210
2211 tfile->sk.sk_write_space = tun_sock_write_space;
2212 tfile->sk.sk_sndbuf = INT_MAX;
2213
2214 file->private_data = tfile;
2215 set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags);
2216 INIT_LIST_HEAD(&tfile->next);
2217
2218 sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
2219
2220 return 0;
2221}
2222
2223static int tun_chr_close(struct inode *inode, struct file *file)
2224{
2225 struct tun_file *tfile = file->private_data;
2226 struct net *net = tfile->net;
2227
2228 tun_detach(tfile, true);
2229 put_net(net);
2230
2231 return 0;
2232}
2233
2234#ifdef CONFIG_PROC_FS
2235static int tun_chr_show_fdinfo(struct seq_file *m, struct file *f)
2236{
2237 struct tun_struct *tun;
2238 struct ifreq ifr;
2239
2240 memset(&ifr, 0, sizeof(ifr));
2241
2242 rtnl_lock();
2243 tun = tun_get(f);
2244 if (tun)
2245 tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
2246 rtnl_unlock();
2247
2248 if (tun)
2249 tun_put(tun);
2250
2251 return seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
2252}
2253#endif
2254
2255static const struct file_operations tun_fops = {
2256 .owner = THIS_MODULE,
2257 .llseek = no_llseek,
2258 .read = do_sync_read,
2259 .aio_read = tun_chr_aio_read,
2260 .write = do_sync_write,
2261 .aio_write = tun_chr_aio_write,
2262 .poll = tun_chr_poll,
2263 .unlocked_ioctl = tun_chr_ioctl,
2264#ifdef CONFIG_COMPAT
2265 .compat_ioctl = tun_chr_compat_ioctl,
2266#endif
2267 .open = tun_chr_open,
2268 .release = tun_chr_close,
2269 .fasync = tun_chr_fasync,
2270#ifdef CONFIG_PROC_FS
2271 .show_fdinfo = tun_chr_show_fdinfo,
2272#endif
2273};
2274
2275static struct miscdevice tun_miscdev = {
2276 .minor = TUN_MINOR,
2277 .name = "tun",
2278 .nodename = "net/tun",
2279 .fops = &tun_fops,
2280};
2281
2282/* ethtool interface */
2283
2284static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
2285{
2286 cmd->supported = 0;
2287 cmd->advertising = 0;
2288 ethtool_cmd_speed_set(cmd, SPEED_10);
2289 cmd->duplex = DUPLEX_FULL;
2290 cmd->port = PORT_TP;
2291 cmd->phy_address = 0;
2292 cmd->transceiver = XCVR_INTERNAL;
2293 cmd->autoneg = AUTONEG_DISABLE;
2294 cmd->maxtxpkt = 0;
2295 cmd->maxrxpkt = 0;
2296 return 0;
2297}
2298
2299static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
2300{
2301 struct tun_struct *tun = netdev_priv(dev);
2302
2303 strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
2304 strlcpy(info->version, DRV_VERSION, sizeof(info->version));
2305
2306 switch (tun->flags & TUN_TYPE_MASK) {
2307 case TUN_TUN_DEV:
2308 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
2309 break;
2310 case TUN_TAP_DEV:
2311 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
2312 break;
2313 }
2314}
2315
2316static u32 tun_get_msglevel(struct net_device *dev)
2317{
2318#ifdef TUN_DEBUG
2319 struct tun_struct *tun = netdev_priv(dev);
2320 return tun->debug;
2321#else
2322 return -EOPNOTSUPP;
2323#endif
2324}
2325
2326static void tun_set_msglevel(struct net_device *dev, u32 value)
2327{
2328#ifdef TUN_DEBUG
2329 struct tun_struct *tun = netdev_priv(dev);
2330 tun->debug = value;
2331#endif
2332}
2333
2334static const struct ethtool_ops tun_ethtool_ops = {
2335 .get_settings = tun_get_settings,
2336 .get_drvinfo = tun_get_drvinfo,
2337 .get_msglevel = tun_get_msglevel,
2338 .set_msglevel = tun_set_msglevel,
2339 .get_link = ethtool_op_get_link,
2340 .get_ts_info = ethtool_op_get_ts_info,
2341};
2342
2343
2344static int __init tun_init(void)
2345{
2346 int ret = 0;
2347
2348 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
2349 pr_info("%s\n", DRV_COPYRIGHT);
2350
2351 ret = rtnl_link_register(&tun_link_ops);
2352 if (ret) {
2353 pr_err("Can't register link_ops\n");
2354 goto err_linkops;
2355 }
2356
2357 ret = misc_register(&tun_miscdev);
2358 if (ret) {
2359 pr_err("Can't register misc device %d\n", TUN_MINOR);
2360 goto err_misc;
2361 }
2362 return 0;
2363err_misc:
2364 rtnl_link_unregister(&tun_link_ops);
2365err_linkops:
2366 return ret;
2367}
2368
2369static void tun_cleanup(void)
2370{
2371 misc_deregister(&tun_miscdev);
2372 rtnl_link_unregister(&tun_link_ops);
2373}
2374
2375/* Get an underlying socket object from tun file. Returns error unless file is
2376 * attached to a device. The returned object works like a packet socket, it
2377 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
2378 * holding a reference to the file for as long as the socket is in use. */
2379struct socket *tun_get_socket(struct file *file)
2380{
2381 struct tun_file *tfile;
2382 if (file->f_op != &tun_fops)
2383 return ERR_PTR(-EINVAL);
2384 tfile = file->private_data;
2385 if (!tfile)
2386 return ERR_PTR(-EBADFD);
2387 return &tfile->socket;
2388}
2389EXPORT_SYMBOL_GPL(tun_get_socket);
2390
2391module_init(tun_init);
2392module_exit(tun_cleanup);
2393MODULE_DESCRIPTION(DRV_DESCRIPTION);
2394MODULE_AUTHOR(DRV_COPYRIGHT);
2395MODULE_LICENSE("GPL");
2396MODULE_ALIAS_MISCDEV(TUN_MINOR);
2397MODULE_ALIAS("devname:net/tun");