]> git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - drivers/net/tun.c
projects / mirror_ubuntu-artful-kernel.git / blob
? search:
summary | shortlog | log | commit | commitdiff | tree
blame | history | raw | HEAD
Merge tag 'for_3.7-fixes-pm' of git://git.kernel.org/pub/scm/linux/kernel/git/khilman...
[mirror_ubuntu-artful-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 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/crc32.h>
64 #include <linux/nsproxy.h>
65 #include <linux/virtio_net.h>
66 #include <linux/rcupdate.h>
67 #include <net/net_namespace.h>
68 #include <net/netns/generic.h>
69 #include <net/rtnetlink.h>
70 #include <net/sock.h>
71 #include <net/cls_cgroup.h>
72
73 #include <asm/uaccess.h>
74
75 /* Uncomment to enable debugging */
76 /* #define TUN_DEBUG 1 */
77
78 #ifdef TUN_DEBUG
79 static int debug;
80
81 #define tun_debug(level, tun, fmt, args...) \
82 do { \
83 if (tun->debug) \
84 netdev_printk(level, tun->dev, fmt, ##args); \
85 } while (0)
86 #define DBG1(level, fmt, args...) \
87 do { \
88 if (debug == 2) \
89 printk(level fmt, ##args); \
90 } while (0)
91 #else
92 #define tun_debug(level, tun, fmt, args...) \
93 do { \
94 if (0) \
95 netdev_printk(level, tun->dev, fmt, ##args); \
96 } while (0)
97 #define DBG1(level, fmt, args...) \
98 do { \
99 if (0) \
100 printk(level fmt, ##args); \
101 } while (0)
102 #endif
103
104 #define GOODCOPY_LEN 128
105
106 #define FLT_EXACT_COUNT 8
107 struct tap_filter {
108 unsigned int count; /* Number of addrs. Zero means disabled */
109 u32 mask[2]; /* Mask of the hashed addrs */
110 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
111 };
112
113 struct tun_file {
114 atomic_t count;
115 struct tun_struct *tun;
116 struct net *net;
117 };
118
119 struct tun_sock;
120
121 struct tun_struct {
122 struct tun_file *tfile;
123 unsigned int flags;
124 kuid_t owner;
125 kgid_t group;
126
127 struct net_device *dev;
128 netdev_features_t set_features;
129 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
130 NETIF_F_TSO6|NETIF_F_UFO)
131 struct fasync_struct *fasync;
132
133 struct tap_filter txflt;
134 struct socket socket;
135 struct socket_wq wq;
136
137 int vnet_hdr_sz;
138
139 #ifdef TUN_DEBUG
140 int debug;
141 #endif
142 };
143
144 struct tun_sock {
145 struct sock sk;
146 struct tun_struct *tun;
147 };
148
149 static inline struct tun_sock *tun_sk(struct sock *sk)
150 {
151 return container_of(sk, struct tun_sock, sk);
152 }
153
154 static int tun_attach(struct tun_struct *tun, struct file *file)
155 {
156 struct tun_file *tfile = file->private_data;
157 int err;
158
159 ASSERT_RTNL();
160
161 netif_tx_lock_bh(tun->dev);
162
163 err = -EINVAL;
164 if (tfile->tun)
165 goto out;
166
167 err = -EBUSY;
168 if (tun->tfile)
169 goto out;
170
171 err = 0;
172 tfile->tun = tun;
173 tun->tfile = tfile;
174 tun->socket.file = file;
175 netif_carrier_on(tun->dev);
176 dev_hold(tun->dev);
177 sock_hold(tun->socket.sk);
178 atomic_inc(&tfile->count);
179
180 out:
181 netif_tx_unlock_bh(tun->dev);
182 return err;
183 }
184
185 static void __tun_detach(struct tun_struct *tun)
186 {
187 /* Detach from net device */
188 netif_tx_lock_bh(tun->dev);
189 netif_carrier_off(tun->dev);
190 tun->tfile = NULL;
191 netif_tx_unlock_bh(tun->dev);
192
193 /* Drop read queue */
194 skb_queue_purge(&tun->socket.sk->sk_receive_queue);
195
196 /* Drop the extra count on the net device */
197 dev_put(tun->dev);
198 }
199
200 static void tun_detach(struct tun_struct *tun)
201 {
202 rtnl_lock();
203 __tun_detach(tun);
204 rtnl_unlock();
205 }
206
207 static struct tun_struct *__tun_get(struct tun_file *tfile)
208 {
209 struct tun_struct *tun = NULL;
210
211 if (atomic_inc_not_zero(&tfile->count))
212 tun = tfile->tun;
213
214 return tun;
215 }
216
217 static struct tun_struct *tun_get(struct file *file)
218 {
219 return __tun_get(file->private_data);
220 }
221
222 static void tun_put(struct tun_struct *tun)
223 {
224 struct tun_file *tfile = tun->tfile;
225
226 if (atomic_dec_and_test(&tfile->count))
227 tun_detach(tfile->tun);
228 }
229
230 /* TAP filtering */
231 static void addr_hash_set(u32 *mask, const u8 *addr)
232 {
233 int n = ether_crc(ETH_ALEN, addr) >> 26;
234 mask[n >> 5] |= (1 << (n & 31));
235 }
236
237 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
238 {
239 int n = ether_crc(ETH_ALEN, addr) >> 26;
240 return mask[n >> 5] & (1 << (n & 31));
241 }
242
243 static int update_filter(struct tap_filter *filter, void __user *arg)
244 {
245 struct { u8 u[ETH_ALEN]; } *addr;
246 struct tun_filter uf;
247 int err, alen, n, nexact;
248
249 if (copy_from_user(&uf, arg, sizeof(uf)))
250 return -EFAULT;
251
252 if (!uf.count) {
253 /* Disabled */
254 filter->count = 0;
255 return 0;
256 }
257
258 alen = ETH_ALEN * uf.count;
259 addr = kmalloc(alen, GFP_KERNEL);
260 if (!addr)
261 return -ENOMEM;
262
263 if (copy_from_user(addr, arg + sizeof(uf), alen)) {
264 err = -EFAULT;
265 goto done;
266 }
267
268 /* The filter is updated without holding any locks. Which is
269 * perfectly safe. We disable it first and in the worst
270 * case we'll accept a few undesired packets. */
271 filter->count = 0;
272 wmb();
273
274 /* Use first set of addresses as an exact filter */
275 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
276 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
277
278 nexact = n;
279
280 /* Remaining multicast addresses are hashed,
281 * unicast will leave the filter disabled. */
282 memset(filter->mask, 0, sizeof(filter->mask));
283 for (; n < uf.count; n++) {
284 if (!is_multicast_ether_addr(addr[n].u)) {
285 err = 0; /* no filter */
286 goto done;
287 }
288 addr_hash_set(filter->mask, addr[n].u);
289 }
290
291 /* For ALLMULTI just set the mask to all ones.
292 * This overrides the mask populated above. */
293 if ((uf.flags & TUN_FLT_ALLMULTI))
294 memset(filter->mask, ~0, sizeof(filter->mask));
295
296 /* Now enable the filter */
297 wmb();
298 filter->count = nexact;
299
300 /* Return the number of exact filters */
301 err = nexact;
302
303 done:
304 kfree(addr);
305 return err;
306 }
307
308 /* Returns: 0 - drop, !=0 - accept */
309 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
310 {
311 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
312 * at this point. */
313 struct ethhdr *eh = (struct ethhdr *) skb->data;
314 int i;
315
316 /* Exact match */
317 for (i = 0; i < filter->count; i++)
318 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
319 return 1;
320
321 /* Inexact match (multicast only) */
322 if (is_multicast_ether_addr(eh->h_dest))
323 return addr_hash_test(filter->mask, eh->h_dest);
324
325 return 0;
326 }
327
328 /*
329 * Checks whether the packet is accepted or not.
330 * Returns: 0 - drop, !=0 - accept
331 */
332 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
333 {
334 if (!filter->count)
335 return 1;
336
337 return run_filter(filter, skb);
338 }
339
340 /* Network device part of the driver */
341
342 static const struct ethtool_ops tun_ethtool_ops;
343
344 /* Net device detach from fd. */
345 static void tun_net_uninit(struct net_device *dev)
346 {
347 struct tun_struct *tun = netdev_priv(dev);
348 struct tun_file *tfile = tun->tfile;
349
350 /* Inform the methods they need to stop using the dev.
351 */
352 if (tfile) {
353 wake_up_all(&tun->wq.wait);
354 if (atomic_dec_and_test(&tfile->count))
355 __tun_detach(tun);
356 }
357 }
358
359 static void tun_free_netdev(struct net_device *dev)
360 {
361 struct tun_struct *tun = netdev_priv(dev);
362
363 BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED, &tun->socket.flags));
364
365 sk_release_kernel(tun->socket.sk);
366 }
367
368 /* Net device open. */
369 static int tun_net_open(struct net_device *dev)
370 {
371 netif_start_queue(dev);
372 return 0;
373 }
374
375 /* Net device close. */
376 static int tun_net_close(struct net_device *dev)
377 {
378 netif_stop_queue(dev);
379 return 0;
380 }
381
382 /* Net device start xmit */
383 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
384 {
385 struct tun_struct *tun = netdev_priv(dev);
386
387 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
388
389 /* Drop packet if interface is not attached */
390 if (!tun->tfile)
391 goto drop;
392
393 /* Drop if the filter does not like it.
394 * This is a noop if the filter is disabled.
395 * Filter can be enabled only for the TAP devices. */
396 if (!check_filter(&tun->txflt, skb))
397 goto drop;
398
399 if (tun->socket.sk->sk_filter &&
400 sk_filter(tun->socket.sk, skb))
401 goto drop;
402
403 if (skb_queue_len(&tun->socket.sk->sk_receive_queue) >= dev->tx_queue_len) {
404 if (!(tun->flags & TUN_ONE_QUEUE)) {
405 /* Normal queueing mode. */
406 /* Packet scheduler handles dropping of further packets. */
407 netif_stop_queue(dev);
408
409 /* We won't see all dropped packets individually, so overrun
410 * error is more appropriate. */
411 dev->stats.tx_fifo_errors++;
412 } else {
413 /* Single queue mode.
414 * Driver handles dropping of all packets itself. */
415 goto drop;
416 }
417 }
418
419 /* Orphan the skb - required as we might hang on to it
420 * for indefinite time. */
421 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
422 goto drop;
423 skb_orphan(skb);
424
425 /* Enqueue packet */
426 skb_queue_tail(&tun->socket.sk->sk_receive_queue, skb);
427
428 /* Notify and wake up reader process */
429 if (tun->flags & TUN_FASYNC)
430 kill_fasync(&tun->fasync, SIGIO, POLL_IN);
431 wake_up_interruptible_poll(&tun->wq.wait, POLLIN |
432 POLLRDNORM | POLLRDBAND);
433 return NETDEV_TX_OK;
434
435 drop:
436 dev->stats.tx_dropped++;
437 kfree_skb(skb);
438 return NETDEV_TX_OK;
439 }
440
441 static void tun_net_mclist(struct net_device *dev)
442 {
443 /*
444 * This callback is supposed to deal with mc filter in
445 * _rx_ path and has nothing to do with the _tx_ path.
446 * In rx path we always accept everything userspace gives us.
447 */
448 }
449
450 #define MIN_MTU 68
451 #define MAX_MTU 65535
452
453 static int
454 tun_net_change_mtu(struct net_device *dev, int new_mtu)
455 {
456 if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
457 return -EINVAL;
458 dev->mtu = new_mtu;
459 return 0;
460 }
461
462 static netdev_features_t tun_net_fix_features(struct net_device *dev,
463 netdev_features_t features)
464 {
465 struct tun_struct *tun = netdev_priv(dev);
466
467 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
468 }
469 #ifdef CONFIG_NET_POLL_CONTROLLER
470 static void tun_poll_controller(struct net_device *dev)
471 {
472 /*
473 * Tun only receives frames when:
474 * 1) the char device endpoint gets data from user space
475 * 2) the tun socket gets a sendmsg call from user space
476 * Since both of those are syncronous operations, we are guaranteed
477 * never to have pending data when we poll for it
478 * so theres nothing to do here but return.
479 * We need this though so netpoll recognizes us as an interface that
480 * supports polling, which enables bridge devices in virt setups to
481 * still use netconsole
482 */
483 return;
484 }
485 #endif
486 static const struct net_device_ops tun_netdev_ops = {
487 .ndo_uninit = tun_net_uninit,
488 .ndo_open = tun_net_open,
489 .ndo_stop = tun_net_close,
490 .ndo_start_xmit = tun_net_xmit,
491 .ndo_change_mtu = tun_net_change_mtu,
492 .ndo_fix_features = tun_net_fix_features,
493 #ifdef CONFIG_NET_POLL_CONTROLLER
494 .ndo_poll_controller = tun_poll_controller,
495 #endif
496 };
497
498 static const struct net_device_ops tap_netdev_ops = {
499 .ndo_uninit = tun_net_uninit,
500 .ndo_open = tun_net_open,
501 .ndo_stop = tun_net_close,
502 .ndo_start_xmit = tun_net_xmit,
503 .ndo_change_mtu = tun_net_change_mtu,
504 .ndo_fix_features = tun_net_fix_features,
505 .ndo_set_rx_mode = tun_net_mclist,
506 .ndo_set_mac_address = eth_mac_addr,
507 .ndo_validate_addr = eth_validate_addr,
508 #ifdef CONFIG_NET_POLL_CONTROLLER
509 .ndo_poll_controller = tun_poll_controller,
510 #endif
511 };
512
513 /* Initialize net device. */
514 static void tun_net_init(struct net_device *dev)
515 {
516 struct tun_struct *tun = netdev_priv(dev);
517
518 switch (tun->flags & TUN_TYPE_MASK) {
519 case TUN_TUN_DEV:
520 dev->netdev_ops = &tun_netdev_ops;
521
522 /* Point-to-Point TUN Device */
523 dev->hard_header_len = 0;
524 dev->addr_len = 0;
525 dev->mtu = 1500;
526
527 /* Zero header length */
528 dev->type = ARPHRD_NONE;
529 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
530 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */
531 break;
532
533 case TUN_TAP_DEV:
534 dev->netdev_ops = &tap_netdev_ops;
535 /* Ethernet TAP Device */
536 ether_setup(dev);
537 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
538
539 eth_hw_addr_random(dev);
540
541 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */
542 break;
543 }
544 }
545
546 /* Character device part */
547
548 /* Poll */
549 static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
550 {
551 struct tun_file *tfile = file->private_data;
552 struct tun_struct *tun = __tun_get(tfile);
553 struct sock *sk;
554 unsigned int mask = 0;
555
556 if (!tun)
557 return POLLERR;
558
559 sk = tun->socket.sk;
560
561 tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
562
563 poll_wait(file, &tun->wq.wait, wait);
564
565 if (!skb_queue_empty(&sk->sk_receive_queue))
566 mask |= POLLIN | POLLRDNORM;
567
568 if (sock_writeable(sk) ||
569 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
570 sock_writeable(sk)))
571 mask |= POLLOUT | POLLWRNORM;
572
573 if (tun->dev->reg_state != NETREG_REGISTERED)
574 mask = POLLERR;
575
576 tun_put(tun);
577 return mask;
578 }
579
580 /* prepad is the amount to reserve at front. len is length after that.
581 * linear is a hint as to how much to copy (usually headers). */
582 static struct sk_buff *tun_alloc_skb(struct tun_struct *tun,
583 size_t prepad, size_t len,
584 size_t linear, int noblock)
585 {
586 struct sock *sk = tun->socket.sk;
587 struct sk_buff *skb;
588 int err;
589
590 sock_update_classid(sk);
591
592 /* Under a page? Don't bother with paged skb. */
593 if (prepad + len < PAGE_SIZE || !linear)
594 linear = len;
595
596 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
597 &err);
598 if (!skb)
599 return ERR_PTR(err);
600
601 skb_reserve(skb, prepad);
602 skb_put(skb, linear);
603 skb->data_len = len - linear;
604 skb->len += len - linear;
605
606 return skb;
607 }
608
609 /* set skb frags from iovec, this can move to core network code for reuse */
610 static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from,
611 int offset, size_t count)
612 {
613 int len = iov_length(from, count) - offset;
614 int copy = skb_headlen(skb);
615 int size, offset1 = 0;
616 int i = 0;
617
618 /* Skip over from offset */
619 while (count && (offset >= from->iov_len)) {
620 offset -= from->iov_len;
621 ++from;
622 --count;
623 }
624
625 /* copy up to skb headlen */
626 while (count && (copy > 0)) {
627 size = min_t(unsigned int, copy, from->iov_len - offset);
628 if (copy_from_user(skb->data + offset1, from->iov_base + offset,
629 size))
630 return -EFAULT;
631 if (copy > size) {
632 ++from;
633 --count;
634 offset = 0;
635 } else
636 offset += size;
637 copy -= size;
638 offset1 += size;
639 }
640
641 if (len == offset1)
642 return 0;
643
644 while (count--) {
645 struct page *page[MAX_SKB_FRAGS];
646 int num_pages;
647 unsigned long base;
648 unsigned long truesize;
649
650 len = from->iov_len - offset;
651 if (!len) {
652 offset = 0;
653 ++from;
654 continue;
655 }
656 base = (unsigned long)from->iov_base + offset;
657 size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT;
658 if (i + size > MAX_SKB_FRAGS)
659 return -EMSGSIZE;
660 num_pages = get_user_pages_fast(base, size, 0, &page[i]);
661 if (num_pages != size) {
662 for (i = 0; i < num_pages; i++)
663 put_page(page[i]);
664 return -EFAULT;
665 }
666 truesize = size * PAGE_SIZE;
667 skb->data_len += len;
668 skb->len += len;
669 skb->truesize += truesize;
670 atomic_add(truesize, &skb->sk->sk_wmem_alloc);
671 while (len) {
672 int off = base & ~PAGE_MASK;
673 int size = min_t(int, len, PAGE_SIZE - off);
674 __skb_fill_page_desc(skb, i, page[i], off, size);
675 skb_shinfo(skb)->nr_frags++;
676 /* increase sk_wmem_alloc */
677 base += size;
678 len -= size;
679 i++;
680 }
681 offset = 0;
682 ++from;
683 }
684 return 0;
685 }
686
687 /* Get packet from user space buffer */
688 static ssize_t tun_get_user(struct tun_struct *tun, void *msg_control,
689 const struct iovec *iv, size_t total_len,
690 size_t count, int noblock)
691 {
692 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
693 struct sk_buff *skb;
694 size_t len = total_len, align = NET_SKB_PAD;
695 struct virtio_net_hdr gso = { 0 };
696 int offset = 0;
697 int copylen;
698 bool zerocopy = false;
699 int err;
700
701 if (!(tun->flags & TUN_NO_PI)) {
702 if ((len -= sizeof(pi)) > total_len)
703 return -EINVAL;
704
705 if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
706 return -EFAULT;
707 offset += sizeof(pi);
708 }
709
710 if (tun->flags & TUN_VNET_HDR) {
711 if ((len -= tun->vnet_hdr_sz) > total_len)
712 return -EINVAL;
713
714 if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
715 return -EFAULT;
716
717 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
718 gso.csum_start + gso.csum_offset + 2 > gso.hdr_len)
719 gso.hdr_len = gso.csum_start + gso.csum_offset + 2;
720
721 if (gso.hdr_len > len)
722 return -EINVAL;
723 offset += tun->vnet_hdr_sz;
724 }
725
726 if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
727 align += NET_IP_ALIGN;
728 if (unlikely(len < ETH_HLEN ||
729 (gso.hdr_len && gso.hdr_len < ETH_HLEN)))
730 return -EINVAL;
731 }
732
733 if (msg_control)
734 zerocopy = true;
735
736 if (zerocopy) {
737 /* Userspace may produce vectors with count greater than
738 * MAX_SKB_FRAGS, so we need to linearize parts of the skb
739 * to let the rest of data to be fit in the frags.
740 */
741 if (count > MAX_SKB_FRAGS) {
742 copylen = iov_length(iv, count - MAX_SKB_FRAGS);
743 if (copylen < offset)
744 copylen = 0;
745 else
746 copylen -= offset;
747 } else
748 copylen = 0;
749 /* There are 256 bytes to be copied in skb, so there is enough
750 * room for skb expand head in case it is used.
751 * The rest of the buffer is mapped from userspace.
752 */
753 if (copylen < gso.hdr_len)
754 copylen = gso.hdr_len;
755 if (!copylen)
756 copylen = GOODCOPY_LEN;
757 } else
758 copylen = len;
759
760 skb = tun_alloc_skb(tun, align, copylen, gso.hdr_len, noblock);
761 if (IS_ERR(skb)) {
762 if (PTR_ERR(skb) != -EAGAIN)
763 tun->dev->stats.rx_dropped++;
764 return PTR_ERR(skb);
765 }
766
767 if (zerocopy)
768 err = zerocopy_sg_from_iovec(skb, iv, offset, count);
769 else
770 err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len);
771
772 if (err) {
773 tun->dev->stats.rx_dropped++;
774 kfree_skb(skb);
775 return -EFAULT;
776 }
777
778 if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
779 if (!skb_partial_csum_set(skb, gso.csum_start,
780 gso.csum_offset)) {
781 tun->dev->stats.rx_frame_errors++;
782 kfree_skb(skb);
783 return -EINVAL;
784 }
785 }
786
787 switch (tun->flags & TUN_TYPE_MASK) {
788 case TUN_TUN_DEV:
789 if (tun->flags & TUN_NO_PI) {
790 switch (skb->data[0] & 0xf0) {
791 case 0x40:
792 pi.proto = htons(ETH_P_IP);
793 break;
794 case 0x60:
795 pi.proto = htons(ETH_P_IPV6);
796 break;
797 default:
798 tun->dev->stats.rx_dropped++;
799 kfree_skb(skb);
800 return -EINVAL;
801 }
802 }
803
804 skb_reset_mac_header(skb);
805 skb->protocol = pi.proto;
806 skb->dev = tun->dev;
807 break;
808 case TUN_TAP_DEV:
809 skb->protocol = eth_type_trans(skb, tun->dev);
810 break;
811 }
812
813 if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
814 pr_debug("GSO!\n");
815 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
816 case VIRTIO_NET_HDR_GSO_TCPV4:
817 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
818 break;
819 case VIRTIO_NET_HDR_GSO_TCPV6:
820 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
821 break;
822 case VIRTIO_NET_HDR_GSO_UDP:
823 skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
824 break;
825 default:
826 tun->dev->stats.rx_frame_errors++;
827 kfree_skb(skb);
828 return -EINVAL;
829 }
830
831 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
832 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
833
834 skb_shinfo(skb)->gso_size = gso.gso_size;
835 if (skb_shinfo(skb)->gso_size == 0) {
836 tun->dev->stats.rx_frame_errors++;
837 kfree_skb(skb);
838 return -EINVAL;
839 }
840
841 /* Header must be checked, and gso_segs computed. */
842 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
843 skb_shinfo(skb)->gso_segs = 0;
844 }
845
846 /* copy skb_ubuf_info for callback when skb has no error */
847 if (zerocopy) {
848 skb_shinfo(skb)->destructor_arg = msg_control;
849 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
850 }
851
852 netif_rx_ni(skb);
853
854 tun->dev->stats.rx_packets++;
855 tun->dev->stats.rx_bytes += len;
856
857 return total_len;
858 }
859
860 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
861 unsigned long count, loff_t pos)
862 {
863 struct file *file = iocb->ki_filp;
864 struct tun_struct *tun = tun_get(file);
865 ssize_t result;
866
867 if (!tun)
868 return -EBADFD;
869
870 tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count);
871
872 result = tun_get_user(tun, NULL, iv, iov_length(iv, count), count,
873 file->f_flags & O_NONBLOCK);
874
875 tun_put(tun);
876 return result;
877 }
878
879 /* Put packet to the user space buffer */
880 static ssize_t tun_put_user(struct tun_struct *tun,
881 struct sk_buff *skb,
882 const struct iovec *iv, int len)
883 {
884 struct tun_pi pi = { 0, skb->protocol };
885 ssize_t total = 0;
886
887 if (!(tun->flags & TUN_NO_PI)) {
888 if ((len -= sizeof(pi)) < 0)
889 return -EINVAL;
890
891 if (len < skb->len) {
892 /* Packet will be striped */
893 pi.flags |= TUN_PKT_STRIP;
894 }
895
896 if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi)))
897 return -EFAULT;
898 total += sizeof(pi);
899 }
900
901 if (tun->flags & TUN_VNET_HDR) {
902 struct virtio_net_hdr gso = { 0 }; /* no info leak */
903 if ((len -= tun->vnet_hdr_sz) < 0)
904 return -EINVAL;
905
906 if (skb_is_gso(skb)) {
907 struct skb_shared_info *sinfo = skb_shinfo(skb);
908
909 /* This is a hint as to how much should be linear. */
910 gso.hdr_len = skb_headlen(skb);
911 gso.gso_size = sinfo->gso_size;
912 if (sinfo->gso_type & SKB_GSO_TCPV4)
913 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
914 else if (sinfo->gso_type & SKB_GSO_TCPV6)
915 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
916 else if (sinfo->gso_type & SKB_GSO_UDP)
917 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
918 else {
919 pr_err("unexpected GSO type: "
920 "0x%x, gso_size %d, hdr_len %d\n",
921 sinfo->gso_type, gso.gso_size,
922 gso.hdr_len);
923 print_hex_dump(KERN_ERR, "tun: ",
924 DUMP_PREFIX_NONE,
925 16, 1, skb->head,
926 min((int)gso.hdr_len, 64), true);
927 WARN_ON_ONCE(1);
928 return -EINVAL;
929 }
930 if (sinfo->gso_type & SKB_GSO_TCP_ECN)
931 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
932 } else
933 gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
934
935 if (skb->ip_summed == CHECKSUM_PARTIAL) {
936 gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
937 gso.csum_start = skb_checksum_start_offset(skb);
938 gso.csum_offset = skb->csum_offset;
939 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
940 gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
941 } /* else everything is zero */
942
943 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total,
944 sizeof(gso))))
945 return -EFAULT;
946 total += tun->vnet_hdr_sz;
947 }
948
949 len = min_t(int, skb->len, len);
950
951 skb_copy_datagram_const_iovec(skb, 0, iv, total, len);
952 total += skb->len;
953
954 tun->dev->stats.tx_packets++;
955 tun->dev->stats.tx_bytes += len;
956
957 return total;
958 }
959
960 static ssize_t tun_do_read(struct tun_struct *tun,
961 struct kiocb *iocb, const struct iovec *iv,
962 ssize_t len, int noblock)
963 {
964 DECLARE_WAITQUEUE(wait, current);
965 struct sk_buff *skb;
966 ssize_t ret = 0;
967
968 tun_debug(KERN_INFO, tun, "tun_chr_read\n");
969
970 if (unlikely(!noblock))
971 add_wait_queue(&tun->wq.wait, &wait);
972 while (len) {
973 current->state = TASK_INTERRUPTIBLE;
974
975 /* Read frames from the queue */
976 if (!(skb=skb_dequeue(&tun->socket.sk->sk_receive_queue))) {
977 if (noblock) {
978 ret = -EAGAIN;
979 break;
980 }
981 if (signal_pending(current)) {
982 ret = -ERESTARTSYS;
983 break;
984 }
985 if (tun->dev->reg_state != NETREG_REGISTERED) {
986 ret = -EIO;
987 break;
988 }
989
990 /* Nothing to read, let's sleep */
991 schedule();
992 continue;
993 }
994 netif_wake_queue(tun->dev);
995
996 ret = tun_put_user(tun, skb, iv, len);
997 kfree_skb(skb);
998 break;
999 }
1000
1001 current->state = TASK_RUNNING;
1002 if (unlikely(!noblock))
1003 remove_wait_queue(&tun->wq.wait, &wait);
1004
1005 return ret;
1006 }
1007
1008 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
1009 unsigned long count, loff_t pos)
1010 {
1011 struct file *file = iocb->ki_filp;
1012 struct tun_file *tfile = file->private_data;
1013 struct tun_struct *tun = __tun_get(tfile);
1014 ssize_t len, ret;
1015
1016 if (!tun)
1017 return -EBADFD;
1018 len = iov_length(iv, count);
1019 if (len < 0) {
1020 ret = -EINVAL;
1021 goto out;
1022 }
1023
1024 ret = tun_do_read(tun, iocb, iv, len, file->f_flags & O_NONBLOCK);
1025 ret = min_t(ssize_t, ret, len);
1026 out:
1027 tun_put(tun);
1028 return ret;
1029 }
1030
1031 static void tun_setup(struct net_device *dev)
1032 {
1033 struct tun_struct *tun = netdev_priv(dev);
1034
1035 tun->owner = INVALID_UID;
1036 tun->group = INVALID_GID;
1037
1038 dev->ethtool_ops = &tun_ethtool_ops;
1039 dev->destructor = tun_free_netdev;
1040 }
1041
1042 /* Trivial set of netlink ops to allow deleting tun or tap
1043 * device with netlink.
1044 */
1045 static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
1046 {
1047 return -EINVAL;
1048 }
1049
1050 static struct rtnl_link_ops tun_link_ops __read_mostly = {
1051 .kind = DRV_NAME,
1052 .priv_size = sizeof(struct tun_struct),
1053 .setup = tun_setup,
1054 .validate = tun_validate,
1055 };
1056
1057 static void tun_sock_write_space(struct sock *sk)
1058 {
1059 struct tun_struct *tun;
1060 wait_queue_head_t *wqueue;
1061
1062 if (!sock_writeable(sk))
1063 return;
1064
1065 if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
1066 return;
1067
1068 wqueue = sk_sleep(sk);
1069 if (wqueue && waitqueue_active(wqueue))
1070 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1071 POLLWRNORM | POLLWRBAND);
1072
1073 tun = tun_sk(sk)->tun;
1074 kill_fasync(&tun->fasync, SIGIO, POLL_OUT);
1075 }
1076
1077 static void tun_sock_destruct(struct sock *sk)
1078 {
1079 free_netdev(tun_sk(sk)->tun->dev);
1080 }
1081
1082 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock,
1083 struct msghdr *m, size_t total_len)
1084 {
1085 struct tun_struct *tun = container_of(sock, struct tun_struct, socket);
1086 return tun_get_user(tun, m->msg_control, m->msg_iov, total_len,
1087 m->msg_iovlen, m->msg_flags & MSG_DONTWAIT);
1088 }
1089
1090 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
1091 struct msghdr *m, size_t total_len,
1092 int flags)
1093 {
1094 struct tun_struct *tun = container_of(sock, struct tun_struct, socket);
1095 int ret;
1096 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
1097 return -EINVAL;
1098 ret = tun_do_read(tun, iocb, m->msg_iov, total_len,
1099 flags & MSG_DONTWAIT);
1100 if (ret > total_len) {
1101 m->msg_flags |= MSG_TRUNC;
1102 ret = flags & MSG_TRUNC ? ret : total_len;
1103 }
1104 return ret;
1105 }
1106
1107 static int tun_release(struct socket *sock)
1108 {
1109 if (sock->sk)
1110 sock_put(sock->sk);
1111 return 0;
1112 }
1113
1114 /* Ops structure to mimic raw sockets with tun */
1115 static const struct proto_ops tun_socket_ops = {
1116 .sendmsg = tun_sendmsg,
1117 .recvmsg = tun_recvmsg,
1118 .release = tun_release,
1119 };
1120
1121 static struct proto tun_proto = {
1122 .name = "tun",
1123 .owner = THIS_MODULE,
1124 .obj_size = sizeof(struct tun_sock),
1125 };
1126
1127 static int tun_flags(struct tun_struct *tun)
1128 {
1129 int flags = 0;
1130
1131 if (tun->flags & TUN_TUN_DEV)
1132 flags |= IFF_TUN;
1133 else
1134 flags |= IFF_TAP;
1135
1136 if (tun->flags & TUN_NO_PI)
1137 flags |= IFF_NO_PI;
1138
1139 if (tun->flags & TUN_ONE_QUEUE)
1140 flags |= IFF_ONE_QUEUE;
1141
1142 if (tun->flags & TUN_VNET_HDR)
1143 flags |= IFF_VNET_HDR;
1144
1145 return flags;
1146 }
1147
1148 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1149 char *buf)
1150 {
1151 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1152 return sprintf(buf, "0x%x\n", tun_flags(tun));
1153 }
1154
1155 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1156 char *buf)
1157 {
1158 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1159 return uid_valid(tun->owner)?
1160 sprintf(buf, "%u\n",
1161 from_kuid_munged(current_user_ns(), tun->owner)):
1162 sprintf(buf, "-1\n");
1163 }
1164
1165 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1166 char *buf)
1167 {
1168 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1169 return gid_valid(tun->group) ?
1170 sprintf(buf, "%u\n",
1171 from_kgid_munged(current_user_ns(), tun->group)):
1172 sprintf(buf, "-1\n");
1173 }
1174
1175 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1176 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1177 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1178
1179 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1180 {
1181 struct sock *sk;
1182 struct tun_struct *tun;
1183 struct net_device *dev;
1184 int err;
1185
1186 dev = __dev_get_by_name(net, ifr->ifr_name);
1187 if (dev) {
1188 const struct cred *cred = current_cred();
1189
1190 if (ifr->ifr_flags & IFF_TUN_EXCL)
1191 return -EBUSY;
1192 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1193 tun = netdev_priv(dev);
1194 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1195 tun = netdev_priv(dev);
1196 else
1197 return -EINVAL;
1198
1199 if (((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
1200 (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
1201 !capable(CAP_NET_ADMIN))
1202 return -EPERM;
1203 err = security_tun_dev_attach(tun->socket.sk);
1204 if (err < 0)
1205 return err;
1206
1207 err = tun_attach(tun, file);
1208 if (err < 0)
1209 return err;
1210 }
1211 else {
1212 char *name;
1213 unsigned long flags = 0;
1214
1215 if (!capable(CAP_NET_ADMIN))
1216 return -EPERM;
1217 err = security_tun_dev_create();
1218 if (err < 0)
1219 return err;
1220
1221 /* Set dev type */
1222 if (ifr->ifr_flags & IFF_TUN) {
1223 /* TUN device */
1224 flags |= TUN_TUN_DEV;
1225 name = "tun%d";
1226 } else if (ifr->ifr_flags & IFF_TAP) {
1227 /* TAP device */
1228 flags |= TUN_TAP_DEV;
1229 name = "tap%d";
1230 } else
1231 return -EINVAL;
1232
1233 if (*ifr->ifr_name)
1234 name = ifr->ifr_name;
1235
1236 dev = alloc_netdev(sizeof(struct tun_struct), name,
1237 tun_setup);
1238 if (!dev)
1239 return -ENOMEM;
1240
1241 dev_net_set(dev, net);
1242 dev->rtnl_link_ops = &tun_link_ops;
1243
1244 tun = netdev_priv(dev);
1245 tun->dev = dev;
1246 tun->flags = flags;
1247 tun->txflt.count = 0;
1248 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1249 set_bit(SOCK_EXTERNALLY_ALLOCATED, &tun->socket.flags);
1250
1251 err = -ENOMEM;
1252 sk = sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL, &tun_proto);
1253 if (!sk)
1254 goto err_free_dev;
1255
1256 sk_change_net(sk, net);
1257 tun->socket.wq = &tun->wq;
1258 init_waitqueue_head(&tun->wq.wait);
1259 tun->socket.ops = &tun_socket_ops;
1260 sock_init_data(&tun->socket, sk);
1261 sk->sk_write_space = tun_sock_write_space;
1262 sk->sk_sndbuf = INT_MAX;
1263 sock_set_flag(sk, SOCK_ZEROCOPY);
1264
1265 tun_sk(sk)->tun = tun;
1266
1267 security_tun_dev_post_create(sk);
1268
1269 tun_net_init(dev);
1270
1271 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1272 TUN_USER_FEATURES;
1273 dev->features = dev->hw_features;
1274
1275 err = register_netdevice(tun->dev);
1276 if (err < 0)
1277 goto err_free_sk;
1278
1279 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) ||
1280 device_create_file(&tun->dev->dev, &dev_attr_owner) ||
1281 device_create_file(&tun->dev->dev, &dev_attr_group))
1282 pr_err("Failed to create tun sysfs files\n");
1283
1284 sk->sk_destruct = tun_sock_destruct;
1285
1286 err = tun_attach(tun, file);
1287 if (err < 0)
1288 goto failed;
1289 }
1290
1291 tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1292
1293 if (ifr->ifr_flags & IFF_NO_PI)
1294 tun->flags |= TUN_NO_PI;
1295 else
1296 tun->flags &= ~TUN_NO_PI;
1297
1298 if (ifr->ifr_flags & IFF_ONE_QUEUE)
1299 tun->flags |= TUN_ONE_QUEUE;
1300 else
1301 tun->flags &= ~TUN_ONE_QUEUE;
1302
1303 if (ifr->ifr_flags & IFF_VNET_HDR)
1304 tun->flags |= TUN_VNET_HDR;
1305 else
1306 tun->flags &= ~TUN_VNET_HDR;
1307
1308 /* Make sure persistent devices do not get stuck in
1309 * xoff state.
1310 */
1311 if (netif_running(tun->dev))
1312 netif_wake_queue(tun->dev);
1313
1314 strcpy(ifr->ifr_name, tun->dev->name);
1315 return 0;
1316
1317 err_free_sk:
1318 tun_free_netdev(dev);
1319 err_free_dev:
1320 free_netdev(dev);
1321 failed:
1322 return err;
1323 }
1324
1325 static int tun_get_iff(struct net *net, struct tun_struct *tun,
1326 struct ifreq *ifr)
1327 {
1328 tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1329
1330 strcpy(ifr->ifr_name, tun->dev->name);
1331
1332 ifr->ifr_flags = tun_flags(tun);
1333
1334 return 0;
1335 }
1336
1337 /* This is like a cut-down ethtool ops, except done via tun fd so no
1338 * privs required. */
1339 static int set_offload(struct tun_struct *tun, unsigned long arg)
1340 {
1341 netdev_features_t features = 0;
1342
1343 if (arg & TUN_F_CSUM) {
1344 features |= NETIF_F_HW_CSUM;
1345 arg &= ~TUN_F_CSUM;
1346
1347 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1348 if (arg & TUN_F_TSO_ECN) {
1349 features |= NETIF_F_TSO_ECN;
1350 arg &= ~TUN_F_TSO_ECN;
1351 }
1352 if (arg & TUN_F_TSO4)
1353 features |= NETIF_F_TSO;
1354 if (arg & TUN_F_TSO6)
1355 features |= NETIF_F_TSO6;
1356 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1357 }
1358
1359 if (arg & TUN_F_UFO) {
1360 features |= NETIF_F_UFO;
1361 arg &= ~TUN_F_UFO;
1362 }
1363 }
1364
1365 /* This gives the user a way to test for new features in future by
1366 * trying to set them. */
1367 if (arg)
1368 return -EINVAL;
1369
1370 tun->set_features = features;
1371 netdev_update_features(tun->dev);
1372
1373 return 0;
1374 }
1375
1376 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1377 unsigned long arg, int ifreq_len)
1378 {
1379 struct tun_file *tfile = file->private_data;
1380 struct tun_struct *tun;
1381 void __user* argp = (void __user*)arg;
1382 struct sock_fprog fprog;
1383 struct ifreq ifr;
1384 kuid_t owner;
1385 kgid_t group;
1386 int sndbuf;
1387 int vnet_hdr_sz;
1388 int ret;
1389
1390 if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89) {
1391 if (copy_from_user(&ifr, argp, ifreq_len))
1392 return -EFAULT;
1393 } else {
1394 memset(&ifr, 0, sizeof(ifr));
1395 }
1396 if (cmd == TUNGETFEATURES) {
1397 /* Currently this just means: "what IFF flags are valid?".
1398 * This is needed because we never checked for invalid flags on
1399 * TUNSETIFF. */
1400 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
1401 IFF_VNET_HDR,
1402 (unsigned int __user*)argp);
1403 }
1404
1405 rtnl_lock();
1406
1407 tun = __tun_get(tfile);
1408 if (cmd == TUNSETIFF && !tun) {
1409 ifr.ifr_name[IFNAMSIZ-1] = '\0';
1410
1411 ret = tun_set_iff(tfile->net, file, &ifr);
1412
1413 if (ret)
1414 goto unlock;
1415
1416 if (copy_to_user(argp, &ifr, ifreq_len))
1417 ret = -EFAULT;
1418 goto unlock;
1419 }
1420
1421 ret = -EBADFD;
1422 if (!tun)
1423 goto unlock;
1424
1425 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %d\n", cmd);
1426
1427 ret = 0;
1428 switch (cmd) {
1429 case TUNGETIFF:
1430 ret = tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1431 if (ret)
1432 break;
1433
1434 if (copy_to_user(argp, &ifr, ifreq_len))
1435 ret = -EFAULT;
1436 break;
1437
1438 case TUNSETNOCSUM:
1439 /* Disable/Enable checksum */
1440
1441 /* [unimplemented] */
1442 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
1443 arg ? "disabled" : "enabled");
1444 break;
1445
1446 case TUNSETPERSIST:
1447 /* Disable/Enable persist mode */
1448 if (arg)
1449 tun->flags |= TUN_PERSIST;
1450 else
1451 tun->flags &= ~TUN_PERSIST;
1452
1453 tun_debug(KERN_INFO, tun, "persist %s\n",
1454 arg ? "enabled" : "disabled");
1455 break;
1456
1457 case TUNSETOWNER:
1458 /* Set owner of the device */
1459 owner = make_kuid(current_user_ns(), arg);
1460 if (!uid_valid(owner)) {
1461 ret = -EINVAL;
1462 break;
1463 }
1464 tun->owner = owner;
1465 tun_debug(KERN_INFO, tun, "owner set to %d\n",
1466 from_kuid(&init_user_ns, tun->owner));
1467 break;
1468
1469 case TUNSETGROUP:
1470 /* Set group of the device */
1471 group = make_kgid(current_user_ns(), arg);
1472 if (!gid_valid(group)) {
1473 ret = -EINVAL;
1474 break;
1475 }
1476 tun->group = group;
1477 tun_debug(KERN_INFO, tun, "group set to %d\n",
1478 from_kgid(&init_user_ns, tun->group));
1479 break;
1480
1481 case TUNSETLINK:
1482 /* Only allow setting the type when the interface is down */
1483 if (tun->dev->flags & IFF_UP) {
1484 tun_debug(KERN_INFO, tun,
1485 "Linktype set failed because interface is up\n");
1486 ret = -EBUSY;
1487 } else {
1488 tun->dev->type = (int) arg;
1489 tun_debug(KERN_INFO, tun, "linktype set to %d\n",
1490 tun->dev->type);
1491 ret = 0;
1492 }
1493 break;
1494
1495 #ifdef TUN_DEBUG
1496 case TUNSETDEBUG:
1497 tun->debug = arg;
1498 break;
1499 #endif
1500 case TUNSETOFFLOAD:
1501 ret = set_offload(tun, arg);
1502 break;
1503
1504 case TUNSETTXFILTER:
1505 /* Can be set only for TAPs */
1506 ret = -EINVAL;
1507 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1508 break;
1509 ret = update_filter(&tun->txflt, (void __user *)arg);
1510 break;
1511
1512 case SIOCGIFHWADDR:
1513 /* Get hw address */
1514 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
1515 ifr.ifr_hwaddr.sa_family = tun->dev->type;
1516 if (copy_to_user(argp, &ifr, ifreq_len))
1517 ret = -EFAULT;
1518 break;
1519
1520 case SIOCSIFHWADDR:
1521 /* Set hw address */
1522 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
1523 ifr.ifr_hwaddr.sa_data);
1524
1525 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
1526 break;
1527
1528 case TUNGETSNDBUF:
1529 sndbuf = tun->socket.sk->sk_sndbuf;
1530 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
1531 ret = -EFAULT;
1532 break;
1533
1534 case TUNSETSNDBUF:
1535 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
1536 ret = -EFAULT;
1537 break;
1538 }
1539
1540 tun->socket.sk->sk_sndbuf = sndbuf;
1541 break;
1542
1543 case TUNGETVNETHDRSZ:
1544 vnet_hdr_sz = tun->vnet_hdr_sz;
1545 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
1546 ret = -EFAULT;
1547 break;
1548
1549 case TUNSETVNETHDRSZ:
1550 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
1551 ret = -EFAULT;
1552 break;
1553 }
1554 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
1555 ret = -EINVAL;
1556 break;
1557 }
1558
1559 tun->vnet_hdr_sz = vnet_hdr_sz;
1560 break;
1561
1562 case TUNATTACHFILTER:
1563 /* Can be set only for TAPs */
1564 ret = -EINVAL;
1565 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1566 break;
1567 ret = -EFAULT;
1568 if (copy_from_user(&fprog, argp, sizeof(fprog)))
1569 break;
1570
1571 ret = sk_attach_filter(&fprog, tun->socket.sk);
1572 break;
1573
1574 case TUNDETACHFILTER:
1575 /* Can be set only for TAPs */
1576 ret = -EINVAL;
1577 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1578 break;
1579 ret = sk_detach_filter(tun->socket.sk);
1580 break;
1581
1582 default:
1583 ret = -EINVAL;
1584 break;
1585 }
1586
1587 unlock:
1588 rtnl_unlock();
1589 if (tun)
1590 tun_put(tun);
1591 return ret;
1592 }
1593
1594 static long tun_chr_ioctl(struct file *file,
1595 unsigned int cmd, unsigned long arg)
1596 {
1597 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
1598 }
1599
1600 #ifdef CONFIG_COMPAT
1601 static long tun_chr_compat_ioctl(struct file *file,
1602 unsigned int cmd, unsigned long arg)
1603 {
1604 switch (cmd) {
1605 case TUNSETIFF:
1606 case TUNGETIFF:
1607 case TUNSETTXFILTER:
1608 case TUNGETSNDBUF:
1609 case TUNSETSNDBUF:
1610 case SIOCGIFHWADDR:
1611 case SIOCSIFHWADDR:
1612 arg = (unsigned long)compat_ptr(arg);
1613 break;
1614 default:
1615 arg = (compat_ulong_t)arg;
1616 break;
1617 }
1618
1619 /*
1620 * compat_ifreq is shorter than ifreq, so we must not access beyond
1621 * the end of that structure. All fields that are used in this
1622 * driver are compatible though, we don't need to convert the
1623 * contents.
1624 */
1625 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
1626 }
1627 #endif /* CONFIG_COMPAT */
1628
1629 static int tun_chr_fasync(int fd, struct file *file, int on)
1630 {
1631 struct tun_struct *tun = tun_get(file);
1632 int ret;
1633
1634 if (!tun)
1635 return -EBADFD;
1636
1637 tun_debug(KERN_INFO, tun, "tun_chr_fasync %d\n", on);
1638
1639 if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
1640 goto out;
1641
1642 if (on) {
1643 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
1644 if (ret)
1645 goto out;
1646 tun->flags |= TUN_FASYNC;
1647 } else
1648 tun->flags &= ~TUN_FASYNC;
1649 ret = 0;
1650 out:
1651 tun_put(tun);
1652 return ret;
1653 }
1654
1655 static int tun_chr_open(struct inode *inode, struct file * file)
1656 {
1657 struct tun_file *tfile;
1658
1659 DBG1(KERN_INFO, "tunX: tun_chr_open\n");
1660
1661 tfile = kmalloc(sizeof(*tfile), GFP_KERNEL);
1662 if (!tfile)
1663 return -ENOMEM;
1664 atomic_set(&tfile->count, 0);
1665 tfile->tun = NULL;
1666 tfile->net = get_net(current->nsproxy->net_ns);
1667 file->private_data = tfile;
1668 return 0;
1669 }
1670
1671 static int tun_chr_close(struct inode *inode, struct file *file)
1672 {
1673 struct tun_file *tfile = file->private_data;
1674 struct tun_struct *tun;
1675
1676 tun = __tun_get(tfile);
1677 if (tun) {
1678 struct net_device *dev = tun->dev;
1679
1680 tun_debug(KERN_INFO, tun, "tun_chr_close\n");
1681
1682 __tun_detach(tun);
1683
1684 /* If desirable, unregister the netdevice. */
1685 if (!(tun->flags & TUN_PERSIST)) {
1686 rtnl_lock();
1687 if (dev->reg_state == NETREG_REGISTERED)
1688 unregister_netdevice(dev);
1689 rtnl_unlock();
1690 }
1691 }
1692
1693 tun = tfile->tun;
1694 if (tun)
1695 sock_put(tun->socket.sk);
1696
1697 put_net(tfile->net);
1698 kfree(tfile);
1699
1700 return 0;
1701 }
1702
1703 static const struct file_operations tun_fops = {
1704 .owner = THIS_MODULE,
1705 .llseek = no_llseek,
1706 .read = do_sync_read,
1707 .aio_read = tun_chr_aio_read,
1708 .write = do_sync_write,
1709 .aio_write = tun_chr_aio_write,
1710 .poll = tun_chr_poll,
1711 .unlocked_ioctl = tun_chr_ioctl,
1712 #ifdef CONFIG_COMPAT
1713 .compat_ioctl = tun_chr_compat_ioctl,
1714 #endif
1715 .open = tun_chr_open,
1716 .release = tun_chr_close,
1717 .fasync = tun_chr_fasync
1718 };
1719
1720 static struct miscdevice tun_miscdev = {
1721 .minor = TUN_MINOR,
1722 .name = "tun",
1723 .nodename = "net/tun",
1724 .fops = &tun_fops,
1725 };
1726
1727 /* ethtool interface */
1728
1729 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
1730 {
1731 cmd->supported = 0;
1732 cmd->advertising = 0;
1733 ethtool_cmd_speed_set(cmd, SPEED_10);
1734 cmd->duplex = DUPLEX_FULL;
1735 cmd->port = PORT_TP;
1736 cmd->phy_address = 0;
1737 cmd->transceiver = XCVR_INTERNAL;
1738 cmd->autoneg = AUTONEG_DISABLE;
1739 cmd->maxtxpkt = 0;
1740 cmd->maxrxpkt = 0;
1741 return 0;
1742 }
1743
1744 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
1745 {
1746 struct tun_struct *tun = netdev_priv(dev);
1747
1748 strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
1749 strlcpy(info->version, DRV_VERSION, sizeof(info->version));
1750
1751 switch (tun->flags & TUN_TYPE_MASK) {
1752 case TUN_TUN_DEV:
1753 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
1754 break;
1755 case TUN_TAP_DEV:
1756 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
1757 break;
1758 }
1759 }
1760
1761 static u32 tun_get_msglevel(struct net_device *dev)
1762 {
1763 #ifdef TUN_DEBUG
1764 struct tun_struct *tun = netdev_priv(dev);
1765 return tun->debug;
1766 #else
1767 return -EOPNOTSUPP;
1768 #endif
1769 }
1770
1771 static void tun_set_msglevel(struct net_device *dev, u32 value)
1772 {
1773 #ifdef TUN_DEBUG
1774 struct tun_struct *tun = netdev_priv(dev);
1775 tun->debug = value;
1776 #endif
1777 }
1778
1779 static const struct ethtool_ops tun_ethtool_ops = {
1780 .get_settings = tun_get_settings,
1781 .get_drvinfo = tun_get_drvinfo,
1782 .get_msglevel = tun_get_msglevel,
1783 .set_msglevel = tun_set_msglevel,
1784 .get_link = ethtool_op_get_link,
1785 };
1786
1787
1788 static int __init tun_init(void)
1789 {
1790 int ret = 0;
1791
1792 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
1793 pr_info("%s\n", DRV_COPYRIGHT);
1794
1795 ret = rtnl_link_register(&tun_link_ops);
1796 if (ret) {
1797 pr_err("Can't register link_ops\n");
1798 goto err_linkops;
1799 }
1800
1801 ret = misc_register(&tun_miscdev);
1802 if (ret) {
1803 pr_err("Can't register misc device %d\n", TUN_MINOR);
1804 goto err_misc;
1805 }
1806 return 0;
1807 err_misc:
1808 rtnl_link_unregister(&tun_link_ops);
1809 err_linkops:
1810 return ret;
1811 }
1812
1813 static void tun_cleanup(void)
1814 {
1815 misc_deregister(&tun_miscdev);
1816 rtnl_link_unregister(&tun_link_ops);
1817 }
1818
1819 /* Get an underlying socket object from tun file. Returns error unless file is
1820 * attached to a device. The returned object works like a packet socket, it
1821 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
1822 * holding a reference to the file for as long as the socket is in use. */
1823 struct socket *tun_get_socket(struct file *file)
1824 {
1825 struct tun_struct *tun;
1826 if (file->f_op != &tun_fops)
1827 return ERR_PTR(-EINVAL);
1828 tun = tun_get(file);
1829 if (!tun)
1830 return ERR_PTR(-EBADFD);
1831 tun_put(tun);
1832 return &tun->socket;
1833 }
1834 EXPORT_SYMBOL_GPL(tun_get_socket);
1835
1836 module_init(tun_init);
1837 module_exit(tun_cleanup);
1838 MODULE_DESCRIPTION(DRV_DESCRIPTION);
1839 MODULE_AUTHOR(DRV_COPYRIGHT);
1840 MODULE_LICENSE("GPL");
1841 MODULE_ALIAS_MISCDEV(TUN_MINOR);
1842 MODULE_ALIAS("devname:net/tun");
Ubuntu Artful kernel mirror