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tun: There is no longer any need to deny changing network namespaces
[mirror_ubuntu-bionic-kernel.git] / drivers / net / tun.c
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 random_ether_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 DRV_NAME "tun"
38 #define DRV_VERSION "1.6"
39 #define DRV_DESCRIPTION "Universal TUN/TAP device driver"
40 #define DRV_COPYRIGHT "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
41
42 #include <linux/module.h>
43 #include <linux/errno.h>
44 #include <linux/kernel.h>
45 #include <linux/major.h>
46 #include <linux/slab.h>
47 #include <linux/smp_lock.h>
48 #include <linux/poll.h>
49 #include <linux/fcntl.h>
50 #include <linux/init.h>
51 #include <linux/skbuff.h>
52 #include <linux/netdevice.h>
53 #include <linux/etherdevice.h>
54 #include <linux/miscdevice.h>
55 #include <linux/ethtool.h>
56 #include <linux/rtnetlink.h>
57 #include <linux/if.h>
58 #include <linux/if_arp.h>
59 #include <linux/if_ether.h>
60 #include <linux/if_tun.h>
61 #include <linux/crc32.h>
62 #include <linux/nsproxy.h>
63 #include <linux/virtio_net.h>
64 #include <net/net_namespace.h>
65 #include <net/netns/generic.h>
66
67 #include <asm/system.h>
68 #include <asm/uaccess.h>
69
70 /* Uncomment to enable debugging */
71 /* #define TUN_DEBUG 1 */
72
73 #ifdef TUN_DEBUG
74 static int debug;
75
76 #define DBG if(tun->debug)printk
77 #define DBG1 if(debug==2)printk
78 #else
79 #define DBG( a... )
80 #define DBG1( a... )
81 #endif
82
83 #define FLT_EXACT_COUNT 8
84 struct tap_filter {
85 unsigned int count; /* Number of addrs. Zero means disabled */
86 u32 mask[2]; /* Mask of the hashed addrs */
87 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
88 };
89
90 struct tun_file {
91 atomic_t count;
92 struct tun_struct *tun;
93 struct net *net;
94 wait_queue_head_t read_wait;
95 };
96
97 struct tun_struct {
98 struct tun_file *tfile;
99 unsigned int flags;
100 uid_t owner;
101 gid_t group;
102
103 struct sk_buff_head readq;
104
105 struct net_device *dev;
106 struct fasync_struct *fasync;
107
108 struct tap_filter txflt;
109
110 #ifdef TUN_DEBUG
111 int debug;
112 #endif
113 };
114
115 static int tun_attach(struct tun_struct *tun, struct file *file)
116 {
117 struct tun_file *tfile = file->private_data;
118 const struct cred *cred = current_cred();
119 int err;
120
121 ASSERT_RTNL();
122
123 /* Check permissions */
124 if (((tun->owner != -1 && cred->euid != tun->owner) ||
125 (tun->group != -1 && cred->egid != tun->group)) &&
126 !capable(CAP_NET_ADMIN))
127 return -EPERM;
128
129 netif_tx_lock_bh(tun->dev);
130
131 err = -EINVAL;
132 if (tfile->tun)
133 goto out;
134
135 err = -EBUSY;
136 if (tun->tfile)
137 goto out;
138
139 err = 0;
140 tfile->tun = tun;
141 tun->tfile = tfile;
142 dev_hold(tun->dev);
143 atomic_inc(&tfile->count);
144
145 out:
146 netif_tx_unlock_bh(tun->dev);
147 return err;
148 }
149
150 static void __tun_detach(struct tun_struct *tun)
151 {
152 struct tun_file *tfile = tun->tfile;
153
154 /* Detach from net device */
155 netif_tx_lock_bh(tun->dev);
156 tfile->tun = NULL;
157 tun->tfile = NULL;
158 netif_tx_unlock_bh(tun->dev);
159
160 /* Drop read queue */
161 skb_queue_purge(&tun->readq);
162
163 /* Drop the extra count on the net device */
164 dev_put(tun->dev);
165 }
166
167 static void tun_detach(struct tun_struct *tun)
168 {
169 rtnl_lock();
170 __tun_detach(tun);
171 rtnl_unlock();
172 }
173
174 static struct tun_struct *__tun_get(struct tun_file *tfile)
175 {
176 struct tun_struct *tun = NULL;
177
178 if (atomic_inc_not_zero(&tfile->count))
179 tun = tfile->tun;
180
181 return tun;
182 }
183
184 static struct tun_struct *tun_get(struct file *file)
185 {
186 return __tun_get(file->private_data);
187 }
188
189 static void tun_put(struct tun_struct *tun)
190 {
191 struct tun_file *tfile = tun->tfile;
192
193 if (atomic_dec_and_test(&tfile->count))
194 tun_detach(tfile->tun);
195 }
196
197 /* TAP filterting */
198 static void addr_hash_set(u32 *mask, const u8 *addr)
199 {
200 int n = ether_crc(ETH_ALEN, addr) >> 26;
201 mask[n >> 5] |= (1 << (n & 31));
202 }
203
204 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
205 {
206 int n = ether_crc(ETH_ALEN, addr) >> 26;
207 return mask[n >> 5] & (1 << (n & 31));
208 }
209
210 static int update_filter(struct tap_filter *filter, void __user *arg)
211 {
212 struct { u8 u[ETH_ALEN]; } *addr;
213 struct tun_filter uf;
214 int err, alen, n, nexact;
215
216 if (copy_from_user(&uf, arg, sizeof(uf)))
217 return -EFAULT;
218
219 if (!uf.count) {
220 /* Disabled */
221 filter->count = 0;
222 return 0;
223 }
224
225 alen = ETH_ALEN * uf.count;
226 addr = kmalloc(alen, GFP_KERNEL);
227 if (!addr)
228 return -ENOMEM;
229
230 if (copy_from_user(addr, arg + sizeof(uf), alen)) {
231 err = -EFAULT;
232 goto done;
233 }
234
235 /* The filter is updated without holding any locks. Which is
236 * perfectly safe. We disable it first and in the worst
237 * case we'll accept a few undesired packets. */
238 filter->count = 0;
239 wmb();
240
241 /* Use first set of addresses as an exact filter */
242 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
243 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
244
245 nexact = n;
246
247 /* The rest is hashed */
248 memset(filter->mask, 0, sizeof(filter->mask));
249 for (; n < uf.count; n++)
250 addr_hash_set(filter->mask, addr[n].u);
251
252 /* For ALLMULTI just set the mask to all ones.
253 * This overrides the mask populated above. */
254 if ((uf.flags & TUN_FLT_ALLMULTI))
255 memset(filter->mask, ~0, sizeof(filter->mask));
256
257 /* Now enable the filter */
258 wmb();
259 filter->count = nexact;
260
261 /* Return the number of exact filters */
262 err = nexact;
263
264 done:
265 kfree(addr);
266 return err;
267 }
268
269 /* Returns: 0 - drop, !=0 - accept */
270 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
271 {
272 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
273 * at this point. */
274 struct ethhdr *eh = (struct ethhdr *) skb->data;
275 int i;
276
277 /* Exact match */
278 for (i = 0; i < filter->count; i++)
279 if (!compare_ether_addr(eh->h_dest, filter->addr[i]))
280 return 1;
281
282 /* Inexact match (multicast only) */
283 if (is_multicast_ether_addr(eh->h_dest))
284 return addr_hash_test(filter->mask, eh->h_dest);
285
286 return 0;
287 }
288
289 /*
290 * Checks whether the packet is accepted or not.
291 * Returns: 0 - drop, !=0 - accept
292 */
293 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
294 {
295 if (!filter->count)
296 return 1;
297
298 return run_filter(filter, skb);
299 }
300
301 /* Network device part of the driver */
302
303 static const struct ethtool_ops tun_ethtool_ops;
304
305 /* Net device detach from fd. */
306 static void tun_net_uninit(struct net_device *dev)
307 {
308 struct tun_struct *tun = netdev_priv(dev);
309 struct tun_file *tfile = tun->tfile;
310
311 /* Inform the methods they need to stop using the dev.
312 */
313 if (tfile) {
314 wake_up_all(&tfile->read_wait);
315 if (atomic_dec_and_test(&tfile->count))
316 __tun_detach(tun);
317 }
318 }
319
320 /* Net device open. */
321 static int tun_net_open(struct net_device *dev)
322 {
323 netif_start_queue(dev);
324 return 0;
325 }
326
327 /* Net device close. */
328 static int tun_net_close(struct net_device *dev)
329 {
330 netif_stop_queue(dev);
331 return 0;
332 }
333
334 /* Net device start xmit */
335 static int tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
336 {
337 struct tun_struct *tun = netdev_priv(dev);
338
339 DBG(KERN_INFO "%s: tun_net_xmit %d\n", tun->dev->name, skb->len);
340
341 /* Drop packet if interface is not attached */
342 if (!tun->tfile)
343 goto drop;
344
345 /* Drop if the filter does not like it.
346 * This is a noop if the filter is disabled.
347 * Filter can be enabled only for the TAP devices. */
348 if (!check_filter(&tun->txflt, skb))
349 goto drop;
350
351 if (skb_queue_len(&tun->readq) >= dev->tx_queue_len) {
352 if (!(tun->flags & TUN_ONE_QUEUE)) {
353 /* Normal queueing mode. */
354 /* Packet scheduler handles dropping of further packets. */
355 netif_stop_queue(dev);
356
357 /* We won't see all dropped packets individually, so overrun
358 * error is more appropriate. */
359 dev->stats.tx_fifo_errors++;
360 } else {
361 /* Single queue mode.
362 * Driver handles dropping of all packets itself. */
363 goto drop;
364 }
365 }
366
367 /* Enqueue packet */
368 skb_queue_tail(&tun->readq, skb);
369 dev->trans_start = jiffies;
370
371 /* Notify and wake up reader process */
372 if (tun->flags & TUN_FASYNC)
373 kill_fasync(&tun->fasync, SIGIO, POLL_IN);
374 wake_up_interruptible(&tun->tfile->read_wait);
375 return 0;
376
377 drop:
378 dev->stats.tx_dropped++;
379 kfree_skb(skb);
380 return 0;
381 }
382
383 static void tun_net_mclist(struct net_device *dev)
384 {
385 /*
386 * This callback is supposed to deal with mc filter in
387 * _rx_ path and has nothing to do with the _tx_ path.
388 * In rx path we always accept everything userspace gives us.
389 */
390 return;
391 }
392
393 #define MIN_MTU 68
394 #define MAX_MTU 65535
395
396 static int
397 tun_net_change_mtu(struct net_device *dev, int new_mtu)
398 {
399 if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
400 return -EINVAL;
401 dev->mtu = new_mtu;
402 return 0;
403 }
404
405 static const struct net_device_ops tun_netdev_ops = {
406 .ndo_uninit = tun_net_uninit,
407 .ndo_open = tun_net_open,
408 .ndo_stop = tun_net_close,
409 .ndo_start_xmit = tun_net_xmit,
410 .ndo_change_mtu = tun_net_change_mtu,
411 };
412
413 static const struct net_device_ops tap_netdev_ops = {
414 .ndo_uninit = tun_net_uninit,
415 .ndo_open = tun_net_open,
416 .ndo_stop = tun_net_close,
417 .ndo_start_xmit = tun_net_xmit,
418 .ndo_change_mtu = tun_net_change_mtu,
419 .ndo_set_multicast_list = tun_net_mclist,
420 .ndo_set_mac_address = eth_mac_addr,
421 .ndo_validate_addr = eth_validate_addr,
422 };
423
424 /* Initialize net device. */
425 static void tun_net_init(struct net_device *dev)
426 {
427 struct tun_struct *tun = netdev_priv(dev);
428
429 switch (tun->flags & TUN_TYPE_MASK) {
430 case TUN_TUN_DEV:
431 dev->netdev_ops = &tun_netdev_ops;
432
433 /* Point-to-Point TUN Device */
434 dev->hard_header_len = 0;
435 dev->addr_len = 0;
436 dev->mtu = 1500;
437
438 /* Zero header length */
439 dev->type = ARPHRD_NONE;
440 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
441 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */
442 break;
443
444 case TUN_TAP_DEV:
445 dev->netdev_ops = &tap_netdev_ops;
446 /* Ethernet TAP Device */
447 ether_setup(dev);
448
449 random_ether_addr(dev->dev_addr);
450
451 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */
452 break;
453 }
454 }
455
456 /* Character device part */
457
458 /* Poll */
459 static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
460 {
461 struct tun_file *tfile = file->private_data;
462 struct tun_struct *tun = __tun_get(tfile);
463 unsigned int mask = POLLOUT | POLLWRNORM;
464
465 if (!tun)
466 return POLLERR;
467
468 DBG(KERN_INFO "%s: tun_chr_poll\n", tun->dev->name);
469
470 poll_wait(file, &tfile->read_wait, wait);
471
472 if (!skb_queue_empty(&tun->readq))
473 mask |= POLLIN | POLLRDNORM;
474
475 if (tun->dev->reg_state != NETREG_REGISTERED)
476 mask = POLLERR;
477
478 tun_put(tun);
479 return mask;
480 }
481
482 /* prepad is the amount to reserve at front. len is length after that.
483 * linear is a hint as to how much to copy (usually headers). */
484 static struct sk_buff *tun_alloc_skb(size_t prepad, size_t len, size_t linear,
485 gfp_t gfp)
486 {
487 struct sk_buff *skb;
488 unsigned int i;
489
490 skb = alloc_skb(prepad + len, gfp|__GFP_NOWARN);
491 if (skb) {
492 skb_reserve(skb, prepad);
493 skb_put(skb, len);
494 return skb;
495 }
496
497 /* Under a page? Don't bother with paged skb. */
498 if (prepad + len < PAGE_SIZE)
499 return NULL;
500
501 /* Start with a normal skb, and add pages. */
502 skb = alloc_skb(prepad + linear, gfp);
503 if (!skb)
504 return NULL;
505
506 skb_reserve(skb, prepad);
507 skb_put(skb, linear);
508
509 len -= linear;
510
511 for (i = 0; i < MAX_SKB_FRAGS; i++) {
512 skb_frag_t *f = &skb_shinfo(skb)->frags[i];
513
514 f->page = alloc_page(gfp|__GFP_ZERO);
515 if (!f->page)
516 break;
517
518 f->page_offset = 0;
519 f->size = PAGE_SIZE;
520
521 skb->data_len += PAGE_SIZE;
522 skb->len += PAGE_SIZE;
523 skb->truesize += PAGE_SIZE;
524 skb_shinfo(skb)->nr_frags++;
525
526 if (len < PAGE_SIZE) {
527 len = 0;
528 break;
529 }
530 len -= PAGE_SIZE;
531 }
532
533 /* Too large, or alloc fail? */
534 if (unlikely(len)) {
535 kfree_skb(skb);
536 skb = NULL;
537 }
538
539 return skb;
540 }
541
542 /* Get packet from user space buffer */
543 static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct iovec *iv, size_t count)
544 {
545 struct tun_pi pi = { 0, __constant_htons(ETH_P_IP) };
546 struct sk_buff *skb;
547 size_t len = count, align = 0;
548 struct virtio_net_hdr gso = { 0 };
549
550 if (!(tun->flags & TUN_NO_PI)) {
551 if ((len -= sizeof(pi)) > count)
552 return -EINVAL;
553
554 if(memcpy_fromiovec((void *)&pi, iv, sizeof(pi)))
555 return -EFAULT;
556 }
557
558 if (tun->flags & TUN_VNET_HDR) {
559 if ((len -= sizeof(gso)) > count)
560 return -EINVAL;
561
562 if (memcpy_fromiovec((void *)&gso, iv, sizeof(gso)))
563 return -EFAULT;
564
565 if (gso.hdr_len > len)
566 return -EINVAL;
567 }
568
569 if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
570 align = NET_IP_ALIGN;
571 if (unlikely(len < ETH_HLEN))
572 return -EINVAL;
573 }
574
575 if (!(skb = tun_alloc_skb(align, len, gso.hdr_len, GFP_KERNEL))) {
576 tun->dev->stats.rx_dropped++;
577 return -ENOMEM;
578 }
579
580 if (skb_copy_datagram_from_iovec(skb, 0, iv, len)) {
581 tun->dev->stats.rx_dropped++;
582 kfree_skb(skb);
583 return -EFAULT;
584 }
585
586 if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
587 if (!skb_partial_csum_set(skb, gso.csum_start,
588 gso.csum_offset)) {
589 tun->dev->stats.rx_frame_errors++;
590 kfree_skb(skb);
591 return -EINVAL;
592 }
593 } else if (tun->flags & TUN_NOCHECKSUM)
594 skb->ip_summed = CHECKSUM_UNNECESSARY;
595
596 switch (tun->flags & TUN_TYPE_MASK) {
597 case TUN_TUN_DEV:
598 if (tun->flags & TUN_NO_PI) {
599 switch (skb->data[0] & 0xf0) {
600 case 0x40:
601 pi.proto = htons(ETH_P_IP);
602 break;
603 case 0x60:
604 pi.proto = htons(ETH_P_IPV6);
605 break;
606 default:
607 tun->dev->stats.rx_dropped++;
608 kfree_skb(skb);
609 return -EINVAL;
610 }
611 }
612
613 skb_reset_mac_header(skb);
614 skb->protocol = pi.proto;
615 skb->dev = tun->dev;
616 break;
617 case TUN_TAP_DEV:
618 skb->protocol = eth_type_trans(skb, tun->dev);
619 break;
620 };
621
622 if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
623 pr_debug("GSO!\n");
624 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
625 case VIRTIO_NET_HDR_GSO_TCPV4:
626 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
627 break;
628 case VIRTIO_NET_HDR_GSO_TCPV6:
629 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
630 break;
631 default:
632 tun->dev->stats.rx_frame_errors++;
633 kfree_skb(skb);
634 return -EINVAL;
635 }
636
637 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
638 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
639
640 skb_shinfo(skb)->gso_size = gso.gso_size;
641 if (skb_shinfo(skb)->gso_size == 0) {
642 tun->dev->stats.rx_frame_errors++;
643 kfree_skb(skb);
644 return -EINVAL;
645 }
646
647 /* Header must be checked, and gso_segs computed. */
648 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
649 skb_shinfo(skb)->gso_segs = 0;
650 }
651
652 netif_rx_ni(skb);
653
654 tun->dev->stats.rx_packets++;
655 tun->dev->stats.rx_bytes += len;
656
657 return count;
658 }
659
660 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
661 unsigned long count, loff_t pos)
662 {
663 struct tun_struct *tun = tun_get(iocb->ki_filp);
664 ssize_t result;
665
666 if (!tun)
667 return -EBADFD;
668
669 DBG(KERN_INFO "%s: tun_chr_write %ld\n", tun->dev->name, count);
670
671 result = tun_get_user(tun, (struct iovec *) iv, iov_length(iv, count));
672
673 tun_put(tun);
674 return result;
675 }
676
677 /* Put packet to the user space buffer */
678 static __inline__ ssize_t tun_put_user(struct tun_struct *tun,
679 struct sk_buff *skb,
680 struct iovec *iv, int len)
681 {
682 struct tun_pi pi = { 0, skb->protocol };
683 ssize_t total = 0;
684
685 if (!(tun->flags & TUN_NO_PI)) {
686 if ((len -= sizeof(pi)) < 0)
687 return -EINVAL;
688
689 if (len < skb->len) {
690 /* Packet will be striped */
691 pi.flags |= TUN_PKT_STRIP;
692 }
693
694 if (memcpy_toiovec(iv, (void *) &pi, sizeof(pi)))
695 return -EFAULT;
696 total += sizeof(pi);
697 }
698
699 if (tun->flags & TUN_VNET_HDR) {
700 struct virtio_net_hdr gso = { 0 }; /* no info leak */
701 if ((len -= sizeof(gso)) < 0)
702 return -EINVAL;
703
704 if (skb_is_gso(skb)) {
705 struct skb_shared_info *sinfo = skb_shinfo(skb);
706
707 /* This is a hint as to how much should be linear. */
708 gso.hdr_len = skb_headlen(skb);
709 gso.gso_size = sinfo->gso_size;
710 if (sinfo->gso_type & SKB_GSO_TCPV4)
711 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
712 else if (sinfo->gso_type & SKB_GSO_TCPV6)
713 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
714 else
715 BUG();
716 if (sinfo->gso_type & SKB_GSO_TCP_ECN)
717 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
718 } else
719 gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
720
721 if (skb->ip_summed == CHECKSUM_PARTIAL) {
722 gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
723 gso.csum_start = skb->csum_start - skb_headroom(skb);
724 gso.csum_offset = skb->csum_offset;
725 } /* else everything is zero */
726
727 if (unlikely(memcpy_toiovec(iv, (void *)&gso, sizeof(gso))))
728 return -EFAULT;
729 total += sizeof(gso);
730 }
731
732 len = min_t(int, skb->len, len);
733
734 skb_copy_datagram_iovec(skb, 0, iv, len);
735 total += len;
736
737 tun->dev->stats.tx_packets++;
738 tun->dev->stats.tx_bytes += len;
739
740 return total;
741 }
742
743 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
744 unsigned long count, loff_t pos)
745 {
746 struct file *file = iocb->ki_filp;
747 struct tun_file *tfile = file->private_data;
748 struct tun_struct *tun = __tun_get(tfile);
749 DECLARE_WAITQUEUE(wait, current);
750 struct sk_buff *skb;
751 ssize_t len, ret = 0;
752
753 if (!tun)
754 return -EBADFD;
755
756 DBG(KERN_INFO "%s: tun_chr_read\n", tun->dev->name);
757
758 len = iov_length(iv, count);
759 if (len < 0) {
760 ret = -EINVAL;
761 goto out;
762 }
763
764 add_wait_queue(&tfile->read_wait, &wait);
765 while (len) {
766 current->state = TASK_INTERRUPTIBLE;
767
768 /* Read frames from the queue */
769 if (!(skb=skb_dequeue(&tun->readq))) {
770 if (file->f_flags & O_NONBLOCK) {
771 ret = -EAGAIN;
772 break;
773 }
774 if (signal_pending(current)) {
775 ret = -ERESTARTSYS;
776 break;
777 }
778 if (tun->dev->reg_state != NETREG_REGISTERED) {
779 ret = -EIO;
780 break;
781 }
782
783 /* Nothing to read, let's sleep */
784 schedule();
785 continue;
786 }
787 netif_wake_queue(tun->dev);
788
789 ret = tun_put_user(tun, skb, (struct iovec *) iv, len);
790 kfree_skb(skb);
791 break;
792 }
793
794 current->state = TASK_RUNNING;
795 remove_wait_queue(&tfile->read_wait, &wait);
796
797 out:
798 tun_put(tun);
799 return ret;
800 }
801
802 static void tun_setup(struct net_device *dev)
803 {
804 struct tun_struct *tun = netdev_priv(dev);
805
806 skb_queue_head_init(&tun->readq);
807
808 tun->owner = -1;
809 tun->group = -1;
810
811 dev->ethtool_ops = &tun_ethtool_ops;
812 dev->destructor = free_netdev;
813 }
814
815 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
816 {
817 struct tun_struct *tun;
818 struct net_device *dev;
819 int err;
820
821 dev = __dev_get_by_name(net, ifr->ifr_name);
822 if (dev) {
823 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
824 tun = netdev_priv(dev);
825 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
826 tun = netdev_priv(dev);
827 else
828 return -EINVAL;
829
830 err = tun_attach(tun, file);
831 if (err < 0)
832 return err;
833 }
834 else {
835 char *name;
836 unsigned long flags = 0;
837
838 err = -EINVAL;
839
840 if (!capable(CAP_NET_ADMIN))
841 return -EPERM;
842
843 /* Set dev type */
844 if (ifr->ifr_flags & IFF_TUN) {
845 /* TUN device */
846 flags |= TUN_TUN_DEV;
847 name = "tun%d";
848 } else if (ifr->ifr_flags & IFF_TAP) {
849 /* TAP device */
850 flags |= TUN_TAP_DEV;
851 name = "tap%d";
852 } else
853 goto failed;
854
855 if (*ifr->ifr_name)
856 name = ifr->ifr_name;
857
858 dev = alloc_netdev(sizeof(struct tun_struct), name,
859 tun_setup);
860 if (!dev)
861 return -ENOMEM;
862
863 dev_net_set(dev, net);
864
865 tun = netdev_priv(dev);
866 tun->dev = dev;
867 tun->flags = flags;
868 tun->txflt.count = 0;
869
870 tun_net_init(dev);
871
872 if (strchr(dev->name, '%')) {
873 err = dev_alloc_name(dev, dev->name);
874 if (err < 0)
875 goto err_free_dev;
876 }
877
878 err = register_netdevice(tun->dev);
879 if (err < 0)
880 goto err_free_dev;
881
882 err = tun_attach(tun, file);
883 if (err < 0)
884 goto err_free_dev;
885 }
886
887 DBG(KERN_INFO "%s: tun_set_iff\n", tun->dev->name);
888
889 if (ifr->ifr_flags & IFF_NO_PI)
890 tun->flags |= TUN_NO_PI;
891 else
892 tun->flags &= ~TUN_NO_PI;
893
894 if (ifr->ifr_flags & IFF_ONE_QUEUE)
895 tun->flags |= TUN_ONE_QUEUE;
896 else
897 tun->flags &= ~TUN_ONE_QUEUE;
898
899 if (ifr->ifr_flags & IFF_VNET_HDR)
900 tun->flags |= TUN_VNET_HDR;
901 else
902 tun->flags &= ~TUN_VNET_HDR;
903
904 /* Make sure persistent devices do not get stuck in
905 * xoff state.
906 */
907 if (netif_running(tun->dev))
908 netif_wake_queue(tun->dev);
909
910 strcpy(ifr->ifr_name, tun->dev->name);
911 return 0;
912
913 err_free_dev:
914 free_netdev(dev);
915 failed:
916 return err;
917 }
918
919 static int tun_get_iff(struct net *net, struct file *file, struct ifreq *ifr)
920 {
921 struct tun_struct *tun = tun_get(file);
922
923 if (!tun)
924 return -EBADFD;
925
926 DBG(KERN_INFO "%s: tun_get_iff\n", tun->dev->name);
927
928 strcpy(ifr->ifr_name, tun->dev->name);
929
930 ifr->ifr_flags = 0;
931
932 if (ifr->ifr_flags & TUN_TUN_DEV)
933 ifr->ifr_flags |= IFF_TUN;
934 else
935 ifr->ifr_flags |= IFF_TAP;
936
937 if (tun->flags & TUN_NO_PI)
938 ifr->ifr_flags |= IFF_NO_PI;
939
940 if (tun->flags & TUN_ONE_QUEUE)
941 ifr->ifr_flags |= IFF_ONE_QUEUE;
942
943 if (tun->flags & TUN_VNET_HDR)
944 ifr->ifr_flags |= IFF_VNET_HDR;
945
946 tun_put(tun);
947 return 0;
948 }
949
950 /* This is like a cut-down ethtool ops, except done via tun fd so no
951 * privs required. */
952 static int set_offload(struct net_device *dev, unsigned long arg)
953 {
954 unsigned int old_features, features;
955
956 old_features = dev->features;
957 /* Unset features, set them as we chew on the arg. */
958 features = (old_features & ~(NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST
959 |NETIF_F_TSO_ECN|NETIF_F_TSO|NETIF_F_TSO6));
960
961 if (arg & TUN_F_CSUM) {
962 features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
963 arg &= ~TUN_F_CSUM;
964
965 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
966 if (arg & TUN_F_TSO_ECN) {
967 features |= NETIF_F_TSO_ECN;
968 arg &= ~TUN_F_TSO_ECN;
969 }
970 if (arg & TUN_F_TSO4)
971 features |= NETIF_F_TSO;
972 if (arg & TUN_F_TSO6)
973 features |= NETIF_F_TSO6;
974 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
975 }
976 }
977
978 /* This gives the user a way to test for new features in future by
979 * trying to set them. */
980 if (arg)
981 return -EINVAL;
982
983 dev->features = features;
984 if (old_features != dev->features)
985 netdev_features_change(dev);
986
987 return 0;
988 }
989
990 static int tun_chr_ioctl(struct inode *inode, struct file *file,
991 unsigned int cmd, unsigned long arg)
992 {
993 struct tun_file *tfile = file->private_data;
994 struct tun_struct *tun;
995 void __user* argp = (void __user*)arg;
996 struct ifreq ifr;
997 int ret;
998
999 if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
1000 if (copy_from_user(&ifr, argp, sizeof ifr))
1001 return -EFAULT;
1002
1003 if (cmd == TUNGETFEATURES) {
1004 /* Currently this just means: "what IFF flags are valid?".
1005 * This is needed because we never checked for invalid flags on
1006 * TUNSETIFF. */
1007 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
1008 IFF_VNET_HDR,
1009 (unsigned int __user*)argp);
1010 }
1011
1012 tun = __tun_get(tfile);
1013 if (cmd == TUNSETIFF && !tun) {
1014 int err;
1015
1016 ifr.ifr_name[IFNAMSIZ-1] = '\0';
1017
1018 rtnl_lock();
1019 err = tun_set_iff(tfile->net, file, &ifr);
1020 rtnl_unlock();
1021
1022 if (err)
1023 return err;
1024
1025 if (copy_to_user(argp, &ifr, sizeof(ifr)))
1026 return -EFAULT;
1027 return 0;
1028 }
1029
1030
1031 if (!tun)
1032 return -EBADFD;
1033
1034 DBG(KERN_INFO "%s: tun_chr_ioctl cmd %d\n", tun->dev->name, cmd);
1035
1036 ret = 0;
1037 switch (cmd) {
1038 case TUNGETIFF:
1039 ret = tun_get_iff(current->nsproxy->net_ns, file, &ifr);
1040 if (ret)
1041 break;
1042
1043 if (copy_to_user(argp, &ifr, sizeof(ifr)))
1044 ret = -EFAULT;
1045 break;
1046
1047 case TUNSETNOCSUM:
1048 /* Disable/Enable checksum */
1049 if (arg)
1050 tun->flags |= TUN_NOCHECKSUM;
1051 else
1052 tun->flags &= ~TUN_NOCHECKSUM;
1053
1054 DBG(KERN_INFO "%s: checksum %s\n",
1055 tun->dev->name, arg ? "disabled" : "enabled");
1056 break;
1057
1058 case TUNSETPERSIST:
1059 /* Disable/Enable persist mode */
1060 if (arg)
1061 tun->flags |= TUN_PERSIST;
1062 else
1063 tun->flags &= ~TUN_PERSIST;
1064
1065 DBG(KERN_INFO "%s: persist %s\n",
1066 tun->dev->name, arg ? "enabled" : "disabled");
1067 break;
1068
1069 case TUNSETOWNER:
1070 /* Set owner of the device */
1071 tun->owner = (uid_t) arg;
1072
1073 DBG(KERN_INFO "%s: owner set to %d\n", tun->dev->name, tun->owner);
1074 break;
1075
1076 case TUNSETGROUP:
1077 /* Set group of the device */
1078 tun->group= (gid_t) arg;
1079
1080 DBG(KERN_INFO "%s: group set to %d\n", tun->dev->name, tun->group);
1081 break;
1082
1083 case TUNSETLINK:
1084 /* Only allow setting the type when the interface is down */
1085 rtnl_lock();
1086 if (tun->dev->flags & IFF_UP) {
1087 DBG(KERN_INFO "%s: Linktype set failed because interface is up\n",
1088 tun->dev->name);
1089 ret = -EBUSY;
1090 } else {
1091 tun->dev->type = (int) arg;
1092 DBG(KERN_INFO "%s: linktype set to %d\n", tun->dev->name, tun->dev->type);
1093 ret = 0;
1094 }
1095 rtnl_unlock();
1096 break;
1097
1098 #ifdef TUN_DEBUG
1099 case TUNSETDEBUG:
1100 tun->debug = arg;
1101 break;
1102 #endif
1103 case TUNSETOFFLOAD:
1104 rtnl_lock();
1105 ret = set_offload(tun->dev, arg);
1106 rtnl_unlock();
1107 break;
1108
1109 case TUNSETTXFILTER:
1110 /* Can be set only for TAPs */
1111 ret = -EINVAL;
1112 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1113 break;
1114 rtnl_lock();
1115 ret = update_filter(&tun->txflt, (void __user *)arg);
1116 rtnl_unlock();
1117 break;
1118
1119 case SIOCGIFHWADDR:
1120 /* Get hw addres */
1121 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
1122 ifr.ifr_hwaddr.sa_family = tun->dev->type;
1123 if (copy_to_user(argp, &ifr, sizeof ifr))
1124 ret = -EFAULT;
1125 break;
1126
1127 case SIOCSIFHWADDR:
1128 /* Set hw address */
1129 DBG(KERN_DEBUG "%s: set hw address: %pM\n",
1130 tun->dev->name, ifr.ifr_hwaddr.sa_data);
1131
1132 rtnl_lock();
1133 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
1134 rtnl_unlock();
1135 break;
1136 default:
1137 ret = -EINVAL;
1138 break;
1139 };
1140
1141 tun_put(tun);
1142 return ret;
1143 }
1144
1145 static int tun_chr_fasync(int fd, struct file *file, int on)
1146 {
1147 struct tun_struct *tun = tun_get(file);
1148 int ret;
1149
1150 if (!tun)
1151 return -EBADFD;
1152
1153 DBG(KERN_INFO "%s: tun_chr_fasync %d\n", tun->dev->name, on);
1154
1155 lock_kernel();
1156 if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
1157 goto out;
1158
1159 if (on) {
1160 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
1161 if (ret)
1162 goto out;
1163 tun->flags |= TUN_FASYNC;
1164 } else
1165 tun->flags &= ~TUN_FASYNC;
1166 ret = 0;
1167 out:
1168 unlock_kernel();
1169 tun_put(tun);
1170 return ret;
1171 }
1172
1173 static int tun_chr_open(struct inode *inode, struct file * file)
1174 {
1175 struct tun_file *tfile;
1176 cycle_kernel_lock();
1177 DBG1(KERN_INFO "tunX: tun_chr_open\n");
1178
1179 tfile = kmalloc(sizeof(*tfile), GFP_KERNEL);
1180 if (!tfile)
1181 return -ENOMEM;
1182 atomic_set(&tfile->count, 0);
1183 tfile->tun = NULL;
1184 tfile->net = get_net(current->nsproxy->net_ns);
1185 init_waitqueue_head(&tfile->read_wait);
1186 file->private_data = tfile;
1187 return 0;
1188 }
1189
1190 static int tun_chr_close(struct inode *inode, struct file *file)
1191 {
1192 struct tun_file *tfile = file->private_data;
1193 struct tun_struct *tun = __tun_get(tfile);
1194
1195
1196 if (tun) {
1197 DBG(KERN_INFO "%s: tun_chr_close\n", tun->dev->name);
1198
1199 rtnl_lock();
1200 __tun_detach(tun);
1201
1202 /* If desireable, unregister the netdevice. */
1203 if (!(tun->flags & TUN_PERSIST))
1204 unregister_netdevice(tun->dev);
1205
1206 rtnl_unlock();
1207 }
1208
1209 put_net(tfile->net);
1210 kfree(tfile);
1211
1212 return 0;
1213 }
1214
1215 static const struct file_operations tun_fops = {
1216 .owner = THIS_MODULE,
1217 .llseek = no_llseek,
1218 .read = do_sync_read,
1219 .aio_read = tun_chr_aio_read,
1220 .write = do_sync_write,
1221 .aio_write = tun_chr_aio_write,
1222 .poll = tun_chr_poll,
1223 .ioctl = tun_chr_ioctl,
1224 .open = tun_chr_open,
1225 .release = tun_chr_close,
1226 .fasync = tun_chr_fasync
1227 };
1228
1229 static struct miscdevice tun_miscdev = {
1230 .minor = TUN_MINOR,
1231 .name = "tun",
1232 .fops = &tun_fops,
1233 };
1234
1235 /* ethtool interface */
1236
1237 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
1238 {
1239 cmd->supported = 0;
1240 cmd->advertising = 0;
1241 cmd->speed = SPEED_10;
1242 cmd->duplex = DUPLEX_FULL;
1243 cmd->port = PORT_TP;
1244 cmd->phy_address = 0;
1245 cmd->transceiver = XCVR_INTERNAL;
1246 cmd->autoneg = AUTONEG_DISABLE;
1247 cmd->maxtxpkt = 0;
1248 cmd->maxrxpkt = 0;
1249 return 0;
1250 }
1251
1252 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
1253 {
1254 struct tun_struct *tun = netdev_priv(dev);
1255
1256 strcpy(info->driver, DRV_NAME);
1257 strcpy(info->version, DRV_VERSION);
1258 strcpy(info->fw_version, "N/A");
1259
1260 switch (tun->flags & TUN_TYPE_MASK) {
1261 case TUN_TUN_DEV:
1262 strcpy(info->bus_info, "tun");
1263 break;
1264 case TUN_TAP_DEV:
1265 strcpy(info->bus_info, "tap");
1266 break;
1267 }
1268 }
1269
1270 static u32 tun_get_msglevel(struct net_device *dev)
1271 {
1272 #ifdef TUN_DEBUG
1273 struct tun_struct *tun = netdev_priv(dev);
1274 return tun->debug;
1275 #else
1276 return -EOPNOTSUPP;
1277 #endif
1278 }
1279
1280 static void tun_set_msglevel(struct net_device *dev, u32 value)
1281 {
1282 #ifdef TUN_DEBUG
1283 struct tun_struct *tun = netdev_priv(dev);
1284 tun->debug = value;
1285 #endif
1286 }
1287
1288 static u32 tun_get_link(struct net_device *dev)
1289 {
1290 struct tun_struct *tun = netdev_priv(dev);
1291 return !!tun->tfile;
1292 }
1293
1294 static u32 tun_get_rx_csum(struct net_device *dev)
1295 {
1296 struct tun_struct *tun = netdev_priv(dev);
1297 return (tun->flags & TUN_NOCHECKSUM) == 0;
1298 }
1299
1300 static int tun_set_rx_csum(struct net_device *dev, u32 data)
1301 {
1302 struct tun_struct *tun = netdev_priv(dev);
1303 if (data)
1304 tun->flags &= ~TUN_NOCHECKSUM;
1305 else
1306 tun->flags |= TUN_NOCHECKSUM;
1307 return 0;
1308 }
1309
1310 static const struct ethtool_ops tun_ethtool_ops = {
1311 .get_settings = tun_get_settings,
1312 .get_drvinfo = tun_get_drvinfo,
1313 .get_msglevel = tun_get_msglevel,
1314 .set_msglevel = tun_set_msglevel,
1315 .get_link = tun_get_link,
1316 .get_rx_csum = tun_get_rx_csum,
1317 .set_rx_csum = tun_set_rx_csum
1318 };
1319
1320 static int tun_init_net(struct net *net)
1321 {
1322 return 0;
1323 }
1324
1325 static void tun_exit_net(struct net *net)
1326 {
1327 struct net_device *dev, *next;
1328
1329 rtnl_lock();
1330 for_each_netdev_safe(net, dev, next) {
1331 if (dev->ethtool_ops != &tun_ethtool_ops)
1332 continue;
1333 DBG(KERN_INFO "%s cleaned up\n", dev->name);
1334 unregister_netdevice(dev);
1335 }
1336 rtnl_unlock();
1337 }
1338
1339 static struct pernet_operations tun_net_ops = {
1340 .init = tun_init_net,
1341 .exit = tun_exit_net,
1342 };
1343
1344 static int __init tun_init(void)
1345 {
1346 int ret = 0;
1347
1348 printk(KERN_INFO "tun: %s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
1349 printk(KERN_INFO "tun: %s\n", DRV_COPYRIGHT);
1350
1351 ret = register_pernet_device(&tun_net_ops);
1352 if (ret) {
1353 printk(KERN_ERR "tun: Can't register pernet ops\n");
1354 goto err_pernet;
1355 }
1356
1357 ret = misc_register(&tun_miscdev);
1358 if (ret) {
1359 printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR);
1360 goto err_misc;
1361 }
1362 return 0;
1363
1364 err_misc:
1365 unregister_pernet_device(&tun_net_ops);
1366 err_pernet:
1367 return ret;
1368 }
1369
1370 static void tun_cleanup(void)
1371 {
1372 misc_deregister(&tun_miscdev);
1373 unregister_pernet_device(&tun_net_ops);
1374 }
1375
1376 module_init(tun_init);
1377 module_exit(tun_cleanup);
1378 MODULE_DESCRIPTION(DRV_DESCRIPTION);
1379 MODULE_AUTHOR(DRV_COPYRIGHT);
1380 MODULE_LICENSE("GPL");
1381 MODULE_ALIAS_MISCDEV(TUN_MINOR);
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