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Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm...
[linux-2.6/btrfs-unstable.git] / drivers / net / tun.c
blob498dc0d4ba5e6c4a55ab7e4d322dc2bdaac83097
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
72 #include <asm/uaccess.h>
73
74 /* Uncomment to enable debugging */
75 /* #define TUN_DEBUG 1 */
76
77 #ifdef TUN_DEBUG
78 static int debug;
79
80 #define tun_debug(level, tun, fmt, args...) \
81 do { \
82 if (tun->debug) \
83 netdev_printk(level, tun->dev, fmt, ##args); \
84 } while (0)
85 #define DBG1(level, fmt, args...) \
86 do { \
87 if (debug == 2) \
88 printk(level fmt, ##args); \
89 } while (0)
90 #else
91 #define tun_debug(level, tun, fmt, args...) \
92 do { \
93 if (0) \
94 netdev_printk(level, tun->dev, fmt, ##args); \
95 } while (0)
96 #define DBG1(level, fmt, args...) \
97 do { \
98 if (0) \
99 printk(level fmt, ##args); \
100 } while (0)
101 #endif
102
103 #define GOODCOPY_LEN 128
104
105 #define FLT_EXACT_COUNT 8
106 struct tap_filter {
107 unsigned int count; /* Number of addrs. Zero means disabled */
108 u32 mask[2]; /* Mask of the hashed addrs */
109 unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
110 };
111
112 struct tun_file {
113 atomic_t count;
114 struct tun_struct *tun;
115 struct net *net;
116 };
117
118 struct tun_sock;
119
120 struct tun_struct {
121 struct tun_file *tfile;
122 unsigned int flags;
123 kuid_t owner;
124 kgid_t group;
125
126 struct net_device *dev;
127 netdev_features_t set_features;
128 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
129 NETIF_F_TSO6|NETIF_F_UFO)
130 struct fasync_struct *fasync;
131
132 struct tap_filter txflt;
133 struct socket socket;
134 struct socket_wq wq;
135
136 int vnet_hdr_sz;
137
138 #ifdef TUN_DEBUG
139 int debug;
140 #endif
141 };
142
143 struct tun_sock {
144 struct sock sk;
145 struct tun_struct *tun;
146 };
147
148 static inline struct tun_sock *tun_sk(struct sock *sk)
149 {
150 return container_of(sk, struct tun_sock, sk);
151 }
152
153 static int tun_attach(struct tun_struct *tun, struct file *file)
154 {
155 struct tun_file *tfile = file->private_data;
156 int err;
157
158 ASSERT_RTNL();
159
160 netif_tx_lock_bh(tun->dev);
161
162 err = -EINVAL;
163 if (tfile->tun)
164 goto out;
165
166 err = -EBUSY;
167 if (tun->tfile)
168 goto out;
169
170 err = 0;
171 tfile->tun = tun;
172 tun->tfile = tfile;
173 tun->socket.file = file;
174 netif_carrier_on(tun->dev);
175 dev_hold(tun->dev);
176 sock_hold(tun->socket.sk);
177 atomic_inc(&tfile->count);
178
179 out:
180 netif_tx_unlock_bh(tun->dev);
181 return err;
182 }
183
184 static void __tun_detach(struct tun_struct *tun)
185 {
186 /* Detach from net device */
187 netif_tx_lock_bh(tun->dev);
188 netif_carrier_off(tun->dev);
189 tun->tfile = NULL;
190 netif_tx_unlock_bh(tun->dev);
191
192 /* Drop read queue */
193 skb_queue_purge(&tun->socket.sk->sk_receive_queue);
194
195 /* Drop the extra count on the net device */
196 dev_put(tun->dev);
197 }
198
199 static void tun_detach(struct tun_struct *tun)
200 {
201 rtnl_lock();
202 __tun_detach(tun);
203 rtnl_unlock();
204 }
205
206 static struct tun_struct *__tun_get(struct tun_file *tfile)
207 {
208 struct tun_struct *tun = NULL;
209
210 if (atomic_inc_not_zero(&tfile->count))
211 tun = tfile->tun;
212
213 return tun;
214 }
215
216 static struct tun_struct *tun_get(struct file *file)
217 {
218 return __tun_get(file->private_data);
219 }
220
221 static void tun_put(struct tun_struct *tun)
222 {
223 struct tun_file *tfile = tun->tfile;
224
225 if (atomic_dec_and_test(&tfile->count))
226 tun_detach(tfile->tun);
227 }
228
229 /* TAP filtering */
230 static void addr_hash_set(u32 *mask, const u8 *addr)
231 {
232 int n = ether_crc(ETH_ALEN, addr) >> 26;
233 mask[n >> 5] |= (1 << (n & 31));
234 }
235
236 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
237 {
238 int n = ether_crc(ETH_ALEN, addr) >> 26;
239 return mask[n >> 5] & (1 << (n & 31));
240 }
241
242 static int update_filter(struct tap_filter *filter, void __user *arg)
243 {
244 struct { u8 u[ETH_ALEN]; } *addr;
245 struct tun_filter uf;
246 int err, alen, n, nexact;
247
248 if (copy_from_user(&uf, arg, sizeof(uf)))
249 return -EFAULT;
250
251 if (!uf.count) {
252 /* Disabled */
253 filter->count = 0;
254 return 0;
255 }
256
257 alen = ETH_ALEN * uf.count;
258 addr = kmalloc(alen, GFP_KERNEL);
259 if (!addr)
260 return -ENOMEM;
261
262 if (copy_from_user(addr, arg + sizeof(uf), alen)) {
263 err = -EFAULT;
264 goto done;
265 }
266
267 /* The filter is updated without holding any locks. Which is
268 * perfectly safe. We disable it first and in the worst
269 * case we'll accept a few undesired packets. */
270 filter->count = 0;
271 wmb();
272
273 /* Use first set of addresses as an exact filter */
274 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
275 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
276
277 nexact = n;
278
279 /* Remaining multicast addresses are hashed,
280 * unicast will leave the filter disabled. */
281 memset(filter->mask, 0, sizeof(filter->mask));
282 for (; n < uf.count; n++) {
283 if (!is_multicast_ether_addr(addr[n].u)) {
284 err = 0; /* no filter */
285 goto done;
286 }
287 addr_hash_set(filter->mask, addr[n].u);
288 }
289
290 /* For ALLMULTI just set the mask to all ones.
291 * This overrides the mask populated above. */
292 if ((uf.flags & TUN_FLT_ALLMULTI))
293 memset(filter->mask, ~0, sizeof(filter->mask));
294
295 /* Now enable the filter */
296 wmb();
297 filter->count = nexact;
298
299 /* Return the number of exact filters */
300 err = nexact;
301
302 done:
303 kfree(addr);
304 return err;
305 }
306
307 /* Returns: 0 - drop, !=0 - accept */
308 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
309 {
310 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
311 * at this point. */
312 struct ethhdr *eh = (struct ethhdr *) skb->data;
313 int i;
314
315 /* Exact match */
316 for (i = 0; i < filter->count; i++)
317 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
318 return 1;
319
320 /* Inexact match (multicast only) */
321 if (is_multicast_ether_addr(eh->h_dest))
322 return addr_hash_test(filter->mask, eh->h_dest);
323
324 return 0;
325 }
326
327 /*
328 * Checks whether the packet is accepted or not.
329 * Returns: 0 - drop, !=0 - accept
330 */
331 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
332 {
333 if (!filter->count)
334 return 1;
335
336 return run_filter(filter, skb);
337 }
338
339 /* Network device part of the driver */
340
341 static const struct ethtool_ops tun_ethtool_ops;
342
343 /* Net device detach from fd. */
344 static void tun_net_uninit(struct net_device *dev)
345 {
346 struct tun_struct *tun = netdev_priv(dev);
347 struct tun_file *tfile = tun->tfile;
348
349 /* Inform the methods they need to stop using the dev.
350 */
351 if (tfile) {
352 wake_up_all(&tun->wq.wait);
353 if (atomic_dec_and_test(&tfile->count))
354 __tun_detach(tun);
355 }
356 }
357
358 static void tun_free_netdev(struct net_device *dev)
359 {
360 struct tun_struct *tun = netdev_priv(dev);
361
362 BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED, &tun->socket.flags));
363
364 sk_release_kernel(tun->socket.sk);
365 }
366
367 /* Net device open. */
368 static int tun_net_open(struct net_device *dev)
369 {
370 netif_start_queue(dev);
371 return 0;
372 }
373
374 /* Net device close. */
375 static int tun_net_close(struct net_device *dev)
376 {
377 netif_stop_queue(dev);
378 return 0;
379 }
380
381 /* Net device start xmit */
382 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
383 {
384 struct tun_struct *tun = netdev_priv(dev);
385
386 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
387
388 /* Drop packet if interface is not attached */
389 if (!tun->tfile)
390 goto drop;
391
392 /* Drop if the filter does not like it.
393 * This is a noop if the filter is disabled.
394 * Filter can be enabled only for the TAP devices. */
395 if (!check_filter(&tun->txflt, skb))
396 goto drop;
397
398 if (tun->socket.sk->sk_filter &&
399 sk_filter(tun->socket.sk, skb))
400 goto drop;
401
402 if (skb_queue_len(&tun->socket.sk->sk_receive_queue) >= dev->tx_queue_len) {
403 if (!(tun->flags & TUN_ONE_QUEUE)) {
404 /* Normal queueing mode. */
405 /* Packet scheduler handles dropping of further packets. */
406 netif_stop_queue(dev);
407
408 /* We won't see all dropped packets individually, so overrun
409 * error is more appropriate. */
410 dev->stats.tx_fifo_errors++;
411 } else {
412 /* Single queue mode.
413 * Driver handles dropping of all packets itself. */
414 goto drop;
415 }
416 }
417
418 /* Orphan the skb - required as we might hang on to it
419 * for indefinite time. */
420 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
421 goto drop;
422 skb_orphan(skb);
423
424 /* Enqueue packet */
425 skb_queue_tail(&tun->socket.sk->sk_receive_queue, skb);
426
427 /* Notify and wake up reader process */
428 if (tun->flags & TUN_FASYNC)
429 kill_fasync(&tun->fasync, SIGIO, POLL_IN);
430 wake_up_interruptible_poll(&tun->wq.wait, POLLIN |
431 POLLRDNORM | POLLRDBAND);
432 return NETDEV_TX_OK;
433
434 drop:
435 dev->stats.tx_dropped++;
436 kfree_skb(skb);
437 return NETDEV_TX_OK;
438 }
439
440 static void tun_net_mclist(struct net_device *dev)
441 {
442 /*
443 * This callback is supposed to deal with mc filter in
444 * _rx_ path and has nothing to do with the _tx_ path.
445 * In rx path we always accept everything userspace gives us.
446 */
447 }
448
449 #define MIN_MTU 68
450 #define MAX_MTU 65535
451
452 static int
453 tun_net_change_mtu(struct net_device *dev, int new_mtu)
454 {
455 if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
456 return -EINVAL;
457 dev->mtu = new_mtu;
458 return 0;
459 }
460
461 static netdev_features_t tun_net_fix_features(struct net_device *dev,
462 netdev_features_t features)
463 {
464 struct tun_struct *tun = netdev_priv(dev);
465
466 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
467 }
468 #ifdef CONFIG_NET_POLL_CONTROLLER
469 static void tun_poll_controller(struct net_device *dev)
470 {
471 /*
472 * Tun only receives frames when:
473 * 1) the char device endpoint gets data from user space
474 * 2) the tun socket gets a sendmsg call from user space
475 * Since both of those are syncronous operations, we are guaranteed
476 * never to have pending data when we poll for it
477 * so theres nothing to do here but return.
478 * We need this though so netpoll recognizes us as an interface that
479 * supports polling, which enables bridge devices in virt setups to
480 * still use netconsole
481 */
482 return;
483 }
484 #endif
485 static const struct net_device_ops tun_netdev_ops = {
486 .ndo_uninit = tun_net_uninit,
487 .ndo_open = tun_net_open,
488 .ndo_stop = tun_net_close,
489 .ndo_start_xmit = tun_net_xmit,
490 .ndo_change_mtu = tun_net_change_mtu,
491 .ndo_fix_features = tun_net_fix_features,
492 #ifdef CONFIG_NET_POLL_CONTROLLER
493 .ndo_poll_controller = tun_poll_controller,
494 #endif
495 };
496
497 static const struct net_device_ops tap_netdev_ops = {
498 .ndo_uninit = tun_net_uninit,
499 .ndo_open = tun_net_open,
500 .ndo_stop = tun_net_close,
501 .ndo_start_xmit = tun_net_xmit,
502 .ndo_change_mtu = tun_net_change_mtu,
503 .ndo_fix_features = tun_net_fix_features,
504 .ndo_set_rx_mode = tun_net_mclist,
505 .ndo_set_mac_address = eth_mac_addr,
506 .ndo_validate_addr = eth_validate_addr,
507 #ifdef CONFIG_NET_POLL_CONTROLLER
508 .ndo_poll_controller = tun_poll_controller,
509 #endif
510 };
511
512 /* Initialize net device. */
513 static void tun_net_init(struct net_device *dev)
514 {
515 struct tun_struct *tun = netdev_priv(dev);
516
517 switch (tun->flags & TUN_TYPE_MASK) {
518 case TUN_TUN_DEV:
519 dev->netdev_ops = &tun_netdev_ops;
520
521 /* Point-to-Point TUN Device */
522 dev->hard_header_len = 0;
523 dev->addr_len = 0;
524 dev->mtu = 1500;
525
526 /* Zero header length */
527 dev->type = ARPHRD_NONE;
528 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
529 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */
530 break;
531
532 case TUN_TAP_DEV:
533 dev->netdev_ops = &tap_netdev_ops;
534 /* Ethernet TAP Device */
535 ether_setup(dev);
536 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
537
538 eth_hw_addr_random(dev);
539
540 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */
541 break;
542 }
543 }
544
545 /* Character device part */
546
547 /* Poll */
548 static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
549 {
550 struct tun_file *tfile = file->private_data;
551 struct tun_struct *tun = __tun_get(tfile);
552 struct sock *sk;
553 unsigned int mask = 0;
554
555 if (!tun)
556 return POLLERR;
557
558 sk = tun->socket.sk;
559
560 tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
561
562 poll_wait(file, &tun->wq.wait, wait);
563
564 if (!skb_queue_empty(&sk->sk_receive_queue))
565 mask |= POLLIN | POLLRDNORM;
566
567 if (sock_writeable(sk) ||
568 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
569 sock_writeable(sk)))
570 mask |= POLLOUT | POLLWRNORM;
571
572 if (tun->dev->reg_state != NETREG_REGISTERED)
573 mask = POLLERR;
574
575 tun_put(tun);
576 return mask;
577 }
578
579 /* prepad is the amount to reserve at front. len is length after that.
580 * linear is a hint as to how much to copy (usually headers). */
581 static struct sk_buff *tun_alloc_skb(struct tun_struct *tun,
582 size_t prepad, size_t len,
583 size_t linear, int noblock)
584 {
585 struct sock *sk = tun->socket.sk;
586 struct sk_buff *skb;
587 int err;
588
589 sock_update_classid(sk);
590
591 /* Under a page? Don't bother with paged skb. */
592 if (prepad + len < PAGE_SIZE || !linear)
593 linear = len;
594
595 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
596 &err);
597 if (!skb)
598 return ERR_PTR(err);
599
600 skb_reserve(skb, prepad);
601 skb_put(skb, linear);
602 skb->data_len = len - linear;
603 skb->len += len - linear;
604
605 return skb;
606 }
607
608 /* set skb frags from iovec, this can move to core network code for reuse */
609 static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from,
610 int offset, size_t count)
611 {
612 int len = iov_length(from, count) - offset;
613 int copy = skb_headlen(skb);
614 int size, offset1 = 0;
615 int i = 0;
616
617 /* Skip over from offset */
618 while (count && (offset >= from->iov_len)) {
619 offset -= from->iov_len;
620 ++from;
621 --count;
622 }
623
624 /* copy up to skb headlen */
625 while (count && (copy > 0)) {
626 size = min_t(unsigned int, copy, from->iov_len - offset);
627 if (copy_from_user(skb->data + offset1, from->iov_base + offset,
628 size))
629 return -EFAULT;
630 if (copy > size) {
631 ++from;
632 --count;
633 offset = 0;
634 } else
635 offset += size;
636 copy -= size;
637 offset1 += size;
638 }
639
640 if (len == offset1)
641 return 0;
642
643 while (count--) {
644 struct page *page[MAX_SKB_FRAGS];
645 int num_pages;
646 unsigned long base;
647 unsigned long truesize;
648
649 len = from->iov_len - offset;
650 if (!len) {
651 offset = 0;
652 ++from;
653 continue;
654 }
655 base = (unsigned long)from->iov_base + offset;
656 size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT;
657 if (i + size > MAX_SKB_FRAGS)
658 return -EMSGSIZE;
659 num_pages = get_user_pages_fast(base, size, 0, &page[i]);
660 if (num_pages != size) {
661 for (i = 0; i < num_pages; i++)
662 put_page(page[i]);
663 return -EFAULT;
664 }
665 truesize = size * PAGE_SIZE;
666 skb->data_len += len;
667 skb->len += len;
668 skb->truesize += truesize;
669 atomic_add(truesize, &skb->sk->sk_wmem_alloc);
670 while (len) {
671 int off = base & ~PAGE_MASK;
672 int size = min_t(int, len, PAGE_SIZE - off);
673 __skb_fill_page_desc(skb, i, page[i], off, size);
674 skb_shinfo(skb)->nr_frags++;
675 /* increase sk_wmem_alloc */
676 base += size;
677 len -= size;
678 i++;
679 }
680 offset = 0;
681 ++from;
682 }
683 return 0;
684 }
685
686 /* Get packet from user space buffer */
687 static ssize_t tun_get_user(struct tun_struct *tun, void *msg_control,
688 const struct iovec *iv, size_t total_len,
689 size_t count, int noblock)
690 {
691 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
692 struct sk_buff *skb;
693 size_t len = total_len, align = NET_SKB_PAD;
694 struct virtio_net_hdr gso = { 0 };
695 int offset = 0;
696 int copylen;
697 bool zerocopy = false;
698 int err;
699
700 if (!(tun->flags & TUN_NO_PI)) {
701 if ((len -= sizeof(pi)) > total_len)
702 return -EINVAL;
703
704 if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
705 return -EFAULT;
706 offset += sizeof(pi);
707 }
708
709 if (tun->flags & TUN_VNET_HDR) {
710 if ((len -= tun->vnet_hdr_sz) > total_len)
711 return -EINVAL;
712
713 if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
714 return -EFAULT;
715
716 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
717 gso.csum_start + gso.csum_offset + 2 > gso.hdr_len)
718 gso.hdr_len = gso.csum_start + gso.csum_offset + 2;
719
720 if (gso.hdr_len > len)
721 return -EINVAL;
722 offset += tun->vnet_hdr_sz;
723 }
724
725 if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
726 align += NET_IP_ALIGN;
727 if (unlikely(len < ETH_HLEN ||
728 (gso.hdr_len && gso.hdr_len < ETH_HLEN)))
729 return -EINVAL;
730 }
731
732 if (msg_control)
733 zerocopy = true;
734
735 if (zerocopy) {
736 /* Userspace may produce vectors with count greater than
737 * MAX_SKB_FRAGS, so we need to linearize parts of the skb
738 * to let the rest of data to be fit in the frags.
739 */
740 if (count > MAX_SKB_FRAGS) {
741 copylen = iov_length(iv, count - MAX_SKB_FRAGS);
742 if (copylen < offset)
743 copylen = 0;
744 else
745 copylen -= offset;
746 } else
747 copylen = 0;
748 /* There are 256 bytes to be copied in skb, so there is enough
749 * room for skb expand head in case it is used.
750 * The rest of the buffer is mapped from userspace.
751 */
752 if (copylen < gso.hdr_len)
753 copylen = gso.hdr_len;
754 if (!copylen)
755 copylen = GOODCOPY_LEN;
756 } else
757 copylen = len;
758
759 skb = tun_alloc_skb(tun, align, copylen, gso.hdr_len, noblock);
760 if (IS_ERR(skb)) {
761 if (PTR_ERR(skb) != -EAGAIN)
762 tun->dev->stats.rx_dropped++;
763 return PTR_ERR(skb);
764 }
765
766 if (zerocopy)
767 err = zerocopy_sg_from_iovec(skb, iv, offset, count);
768 else
769 err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len);
770
771 if (err) {
772 tun->dev->stats.rx_dropped++;
773 kfree_skb(skb);
774 return -EFAULT;
775 }
776
777 if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
778 if (!skb_partial_csum_set(skb, gso.csum_start,
779 gso.csum_offset)) {
780 tun->dev->stats.rx_frame_errors++;
781 kfree_skb(skb);
782 return -EINVAL;
783 }
784 }
785
786 switch (tun->flags & TUN_TYPE_MASK) {
787 case TUN_TUN_DEV:
788 if (tun->flags & TUN_NO_PI) {
789 switch (skb->data[0] & 0xf0) {
790 case 0x40:
791 pi.proto = htons(ETH_P_IP);
792 break;
793 case 0x60:
794 pi.proto = htons(ETH_P_IPV6);
795 break;
796 default:
797 tun->dev->stats.rx_dropped++;
798 kfree_skb(skb);
799 return -EINVAL;
800 }
801 }
802
803 skb_reset_mac_header(skb);
804 skb->protocol = pi.proto;
805 skb->dev = tun->dev;
806 break;
807 case TUN_TAP_DEV:
808 skb->protocol = eth_type_trans(skb, tun->dev);
809 break;
810 }
811
812 if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
813 pr_debug("GSO!\n");
814 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
815 case VIRTIO_NET_HDR_GSO_TCPV4:
816 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
817 break;
818 case VIRTIO_NET_HDR_GSO_TCPV6:
819 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
820 break;
821 case VIRTIO_NET_HDR_GSO_UDP:
822 skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
823 break;
824 default:
825 tun->dev->stats.rx_frame_errors++;
826 kfree_skb(skb);
827 return -EINVAL;
828 }
829
830 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
831 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
832
833 skb_shinfo(skb)->gso_size = gso.gso_size;
834 if (skb_shinfo(skb)->gso_size == 0) {
835 tun->dev->stats.rx_frame_errors++;
836 kfree_skb(skb);
837 return -EINVAL;
838 }
839
840 /* Header must be checked, and gso_segs computed. */
841 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
842 skb_shinfo(skb)->gso_segs = 0;
843 }
844
845 /* copy skb_ubuf_info for callback when skb has no error */
846 if (zerocopy) {
847 skb_shinfo(skb)->destructor_arg = msg_control;
848 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
849 }
850
851 netif_rx_ni(skb);
852
853 tun->dev->stats.rx_packets++;
854 tun->dev->stats.rx_bytes += len;
855
856 return total_len;
857 }
858
859 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
860 unsigned long count, loff_t pos)
861 {
862 struct file *file = iocb->ki_filp;
863 struct tun_struct *tun = tun_get(file);
864 ssize_t result;
865
866 if (!tun)
867 return -EBADFD;
868
869 tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count);
870
871 result = tun_get_user(tun, NULL, iv, iov_length(iv, count), count,
872 file->f_flags & O_NONBLOCK);
873
874 tun_put(tun);
875 return result;
876 }
877
878 /* Put packet to the user space buffer */
879 static ssize_t tun_put_user(struct tun_struct *tun,
880 struct sk_buff *skb,
881 const struct iovec *iv, int len)
882 {
883 struct tun_pi pi = { 0, skb->protocol };
884 ssize_t total = 0;
885
886 if (!(tun->flags & TUN_NO_PI)) {
887 if ((len -= sizeof(pi)) < 0)
888 return -EINVAL;
889
890 if (len < skb->len) {
891 /* Packet will be striped */
892 pi.flags |= TUN_PKT_STRIP;
893 }
894
895 if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi)))
896 return -EFAULT;
897 total += sizeof(pi);
898 }
899
900 if (tun->flags & TUN_VNET_HDR) {
901 struct virtio_net_hdr gso = { 0 }; /* no info leak */
902 if ((len -= tun->vnet_hdr_sz) < 0)
903 return -EINVAL;
904
905 if (skb_is_gso(skb)) {
906 struct skb_shared_info *sinfo = skb_shinfo(skb);
907
908 /* This is a hint as to how much should be linear. */
909 gso.hdr_len = skb_headlen(skb);
910 gso.gso_size = sinfo->gso_size;
911 if (sinfo->gso_type & SKB_GSO_TCPV4)
912 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
913 else if (sinfo->gso_type & SKB_GSO_TCPV6)
914 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
915 else if (sinfo->gso_type & SKB_GSO_UDP)
916 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
917 else {
918 pr_err("unexpected GSO type: "
919 "0x%x, gso_size %d, hdr_len %d\n",
920 sinfo->gso_type, gso.gso_size,
921 gso.hdr_len);
922 print_hex_dump(KERN_ERR, "tun: ",
923 DUMP_PREFIX_NONE,
924 16, 1, skb->head,
925 min((int)gso.hdr_len, 64), true);
926 WARN_ON_ONCE(1);
927 return -EINVAL;
928 }
929 if (sinfo->gso_type & SKB_GSO_TCP_ECN)
930 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
931 } else
932 gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
933
934 if (skb->ip_summed == CHECKSUM_PARTIAL) {
935 gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
936 gso.csum_start = skb_checksum_start_offset(skb);
937 gso.csum_offset = skb->csum_offset;
938 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
939 gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
940 } /* else everything is zero */
941
942 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total,
943 sizeof(gso))))
944 return -EFAULT;
945 total += tun->vnet_hdr_sz;
946 }
947
948 len = min_t(int, skb->len, len);
949
950 skb_copy_datagram_const_iovec(skb, 0, iv, total, len);
951 total += skb->len;
952
953 tun->dev->stats.tx_packets++;
954 tun->dev->stats.tx_bytes += len;
955
956 return total;
957 }
958
959 static ssize_t tun_do_read(struct tun_struct *tun,
960 struct kiocb *iocb, const struct iovec *iv,
961 ssize_t len, int noblock)
962 {
963 DECLARE_WAITQUEUE(wait, current);
964 struct sk_buff *skb;
965 ssize_t ret = 0;
966
967 tun_debug(KERN_INFO, tun, "tun_chr_read\n");
968
969 if (unlikely(!noblock))
970 add_wait_queue(&tun->wq.wait, &wait);
971 while (len) {
972 current->state = TASK_INTERRUPTIBLE;
973
974 /* Read frames from the queue */
975 if (!(skb=skb_dequeue(&tun->socket.sk->sk_receive_queue))) {
976 if (noblock) {
977 ret = -EAGAIN;
978 break;
979 }
980 if (signal_pending(current)) {
981 ret = -ERESTARTSYS;
982 break;
983 }
984 if (tun->dev->reg_state != NETREG_REGISTERED) {
985 ret = -EIO;
986 break;
987 }
988
989 /* Nothing to read, let's sleep */
990 schedule();
991 continue;
992 }
993 netif_wake_queue(tun->dev);
994
995 ret = tun_put_user(tun, skb, iv, len);
996 kfree_skb(skb);
997 break;
998 }
999
1000 current->state = TASK_RUNNING;
1001 if (unlikely(!noblock))
1002 remove_wait_queue(&tun->wq.wait, &wait);
1003
1004 return ret;
1005 }
1006
1007 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
1008 unsigned long count, loff_t pos)
1009 {
1010 struct file *file = iocb->ki_filp;
1011 struct tun_file *tfile = file->private_data;
1012 struct tun_struct *tun = __tun_get(tfile);
1013 ssize_t len, ret;
1014
1015 if (!tun)
1016 return -EBADFD;
1017 len = iov_length(iv, count);
1018 if (len < 0) {
1019 ret = -EINVAL;
1020 goto out;
1021 }
1022
1023 ret = tun_do_read(tun, iocb, iv, len, file->f_flags & O_NONBLOCK);
1024 ret = min_t(ssize_t, ret, len);
1025 out:
1026 tun_put(tun);
1027 return ret;
1028 }
1029
1030 static void tun_setup(struct net_device *dev)
1031 {
1032 struct tun_struct *tun = netdev_priv(dev);
1033
1034 tun->owner = INVALID_UID;
1035 tun->group = INVALID_GID;
1036
1037 dev->ethtool_ops = &tun_ethtool_ops;
1038 dev->destructor = tun_free_netdev;
1039 }
1040
1041 /* Trivial set of netlink ops to allow deleting tun or tap
1042 * device with netlink.
1043 */
1044 static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
1045 {
1046 return -EINVAL;
1047 }
1048
1049 static struct rtnl_link_ops tun_link_ops __read_mostly = {
1050 .kind = DRV_NAME,
1051 .priv_size = sizeof(struct tun_struct),
1052 .setup = tun_setup,
1053 .validate = tun_validate,
1054 };
1055
1056 static void tun_sock_write_space(struct sock *sk)
1057 {
1058 struct tun_struct *tun;
1059 wait_queue_head_t *wqueue;
1060
1061 if (!sock_writeable(sk))
1062 return;
1063
1064 if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
1065 return;
1066
1067 wqueue = sk_sleep(sk);
1068 if (wqueue && waitqueue_active(wqueue))
1069 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1070 POLLWRNORM | POLLWRBAND);
1071
1072 tun = tun_sk(sk)->tun;
1073 kill_fasync(&tun->fasync, SIGIO, POLL_OUT);
1074 }
1075
1076 static void tun_sock_destruct(struct sock *sk)
1077 {
1078 free_netdev(tun_sk(sk)->tun->dev);
1079 }
1080
1081 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock,
1082 struct msghdr *m, size_t total_len)
1083 {
1084 struct tun_struct *tun = container_of(sock, struct tun_struct, socket);
1085 return tun_get_user(tun, m->msg_control, m->msg_iov, total_len,
1086 m->msg_iovlen, m->msg_flags & MSG_DONTWAIT);
1087 }
1088
1089 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
1090 struct msghdr *m, size_t total_len,
1091 int flags)
1092 {
1093 struct tun_struct *tun = container_of(sock, struct tun_struct, socket);
1094 int ret;
1095 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
1096 return -EINVAL;
1097 ret = tun_do_read(tun, iocb, m->msg_iov, total_len,
1098 flags & MSG_DONTWAIT);
1099 if (ret > total_len) {
1100 m->msg_flags |= MSG_TRUNC;
1101 ret = flags & MSG_TRUNC ? ret : total_len;
1102 }
1103 return ret;
1104 }
1105
1106 static int tun_release(struct socket *sock)
1107 {
1108 if (sock->sk)
1109 sock_put(sock->sk);
1110 return 0;
1111 }
1112
1113 /* Ops structure to mimic raw sockets with tun */
1114 static const struct proto_ops tun_socket_ops = {
1115 .sendmsg = tun_sendmsg,
1116 .recvmsg = tun_recvmsg,
1117 .release = tun_release,
1118 };
1119
1120 static struct proto tun_proto = {
1121 .name = "tun",
1122 .owner = THIS_MODULE,
1123 .obj_size = sizeof(struct tun_sock),
1124 };
1125
1126 static int tun_flags(struct tun_struct *tun)
1127 {
1128 int flags = 0;
1129
1130 if (tun->flags & TUN_TUN_DEV)
1131 flags |= IFF_TUN;
1132 else
1133 flags |= IFF_TAP;
1134
1135 if (tun->flags & TUN_NO_PI)
1136 flags |= IFF_NO_PI;
1137
1138 if (tun->flags & TUN_ONE_QUEUE)
1139 flags |= IFF_ONE_QUEUE;
1140
1141 if (tun->flags & TUN_VNET_HDR)
1142 flags |= IFF_VNET_HDR;
1143
1144 return flags;
1145 }
1146
1147 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1148 char *buf)
1149 {
1150 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1151 return sprintf(buf, "0x%x\n", tun_flags(tun));
1152 }
1153
1154 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1155 char *buf)
1156 {
1157 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1158 return uid_valid(tun->owner)?
1159 sprintf(buf, "%u\n",
1160 from_kuid_munged(current_user_ns(), tun->owner)):
1161 sprintf(buf, "-1\n");
1162 }
1163
1164 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1165 char *buf)
1166 {
1167 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1168 return gid_valid(tun->group) ?
1169 sprintf(buf, "%u\n",
1170 from_kgid_munged(current_user_ns(), tun->group)):
1171 sprintf(buf, "-1\n");
1172 }
1173
1174 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1175 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1176 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1177
1178 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1179 {
1180 struct sock *sk;
1181 struct tun_struct *tun;
1182 struct net_device *dev;
1183 int err;
1184
1185 dev = __dev_get_by_name(net, ifr->ifr_name);
1186 if (dev) {
1187 const struct cred *cred = current_cred();
1188
1189 if (ifr->ifr_flags & IFF_TUN_EXCL)
1190 return -EBUSY;
1191 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1192 tun = netdev_priv(dev);
1193 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1194 tun = netdev_priv(dev);
1195 else
1196 return -EINVAL;
1197
1198 if (((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
1199 (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
1200 !capable(CAP_NET_ADMIN))
1201 return -EPERM;
1202 err = security_tun_dev_attach(tun->socket.sk);
1203 if (err < 0)
1204 return err;
1205
1206 err = tun_attach(tun, file);
1207 if (err < 0)
1208 return err;
1209 }
1210 else {
1211 char *name;
1212 unsigned long flags = 0;
1213
1214 if (!capable(CAP_NET_ADMIN))
1215 return -EPERM;
1216 err = security_tun_dev_create();
1217 if (err < 0)
1218 return err;
1219
1220 /* Set dev type */
1221 if (ifr->ifr_flags & IFF_TUN) {
1222 /* TUN device */
1223 flags |= TUN_TUN_DEV;
1224 name = "tun%d";
1225 } else if (ifr->ifr_flags & IFF_TAP) {
1226 /* TAP device */
1227 flags |= TUN_TAP_DEV;
1228 name = "tap%d";
1229 } else
1230 return -EINVAL;
1231
1232 if (*ifr->ifr_name)
1233 name = ifr->ifr_name;
1234
1235 dev = alloc_netdev(sizeof(struct tun_struct), name,
1236 tun_setup);
1237 if (!dev)
1238 return -ENOMEM;
1239
1240 dev_net_set(dev, net);
1241 dev->rtnl_link_ops = &tun_link_ops;
1242
1243 tun = netdev_priv(dev);
1244 tun->dev = dev;
1245 tun->flags = flags;
1246 tun->txflt.count = 0;
1247 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1248 set_bit(SOCK_EXTERNALLY_ALLOCATED, &tun->socket.flags);
1249
1250 err = -ENOMEM;
1251 sk = sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL, &tun_proto);
1252 if (!sk)
1253 goto err_free_dev;
1254
1255 sk_change_net(sk, net);
1256 tun->socket.wq = &tun->wq;
1257 init_waitqueue_head(&tun->wq.wait);
1258 tun->socket.ops = &tun_socket_ops;
1259 sock_init_data(&tun->socket, sk);
1260 sk->sk_write_space = tun_sock_write_space;
1261 sk->sk_sndbuf = INT_MAX;
1262 sock_set_flag(sk, SOCK_ZEROCOPY);
1263
1264 tun_sk(sk)->tun = tun;
1265
1266 security_tun_dev_post_create(sk);
1267
1268 tun_net_init(dev);
1269
1270 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1271 TUN_USER_FEATURES;
1272 dev->features = dev->hw_features;
1273
1274 err = register_netdevice(tun->dev);
1275 if (err < 0)
1276 goto err_free_sk;
1277
1278 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) ||
1279 device_create_file(&tun->dev->dev, &dev_attr_owner) ||
1280 device_create_file(&tun->dev->dev, &dev_attr_group))
1281 pr_err("Failed to create tun sysfs files\n");
1282
1283 sk->sk_destruct = tun_sock_destruct;
1284
1285 err = tun_attach(tun, file);
1286 if (err < 0)
1287 goto failed;
1288 }
1289
1290 tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1291
1292 if (ifr->ifr_flags & IFF_NO_PI)
1293 tun->flags |= TUN_NO_PI;
1294 else
1295 tun->flags &= ~TUN_NO_PI;
1296
1297 if (ifr->ifr_flags & IFF_ONE_QUEUE)
1298 tun->flags |= TUN_ONE_QUEUE;
1299 else
1300 tun->flags &= ~TUN_ONE_QUEUE;
1301
1302 if (ifr->ifr_flags & IFF_VNET_HDR)
1303 tun->flags |= TUN_VNET_HDR;
1304 else
1305 tun->flags &= ~TUN_VNET_HDR;
1306
1307 /* Make sure persistent devices do not get stuck in
1308 * xoff state.
1309 */
1310 if (netif_running(tun->dev))
1311 netif_wake_queue(tun->dev);
1312
1313 strcpy(ifr->ifr_name, tun->dev->name);
1314 return 0;
1315
1316 err_free_sk:
1317 tun_free_netdev(dev);
1318 err_free_dev:
1319 free_netdev(dev);
1320 failed:
1321 return err;
1322 }
1323
1324 static int tun_get_iff(struct net *net, struct tun_struct *tun,
1325 struct ifreq *ifr)
1326 {
1327 tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1328
1329 strcpy(ifr->ifr_name, tun->dev->name);
1330
1331 ifr->ifr_flags = tun_flags(tun);
1332
1333 return 0;
1334 }
1335
1336 /* This is like a cut-down ethtool ops, except done via tun fd so no
1337 * privs required. */
1338 static int set_offload(struct tun_struct *tun, unsigned long arg)
1339 {
1340 netdev_features_t features = 0;
1341
1342 if (arg & TUN_F_CSUM) {
1343 features |= NETIF_F_HW_CSUM;
1344 arg &= ~TUN_F_CSUM;
1345
1346 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1347 if (arg & TUN_F_TSO_ECN) {
1348 features |= NETIF_F_TSO_ECN;
1349 arg &= ~TUN_F_TSO_ECN;
1350 }
1351 if (arg & TUN_F_TSO4)
1352 features |= NETIF_F_TSO;
1353 if (arg & TUN_F_TSO6)
1354 features |= NETIF_F_TSO6;
1355 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1356 }
1357
1358 if (arg & TUN_F_UFO) {
1359 features |= NETIF_F_UFO;
1360 arg &= ~TUN_F_UFO;
1361 }
1362 }
1363
1364 /* This gives the user a way to test for new features in future by
1365 * trying to set them. */
1366 if (arg)
1367 return -EINVAL;
1368
1369 tun->set_features = features;
1370 netdev_update_features(tun->dev);
1371
1372 return 0;
1373 }
1374
1375 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1376 unsigned long arg, int ifreq_len)
1377 {
1378 struct tun_file *tfile = file->private_data;
1379 struct tun_struct *tun;
1380 void __user* argp = (void __user*)arg;
1381 struct sock_fprog fprog;
1382 struct ifreq ifr;
1383 kuid_t owner;
1384 kgid_t group;
1385 int sndbuf;
1386 int vnet_hdr_sz;
1387 int ret;
1388
1389 if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89) {
1390 if (copy_from_user(&ifr, argp, ifreq_len))
1391 return -EFAULT;
1392 } else {
1393 memset(&ifr, 0, sizeof(ifr));
1394 }
1395 if (cmd == TUNGETFEATURES) {
1396 /* Currently this just means: "what IFF flags are valid?".
1397 * This is needed because we never checked for invalid flags on
1398 * TUNSETIFF. */
1399 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
1400 IFF_VNET_HDR,
1401 (unsigned int __user*)argp);
1402 }
1403
1404 rtnl_lock();
1405
1406 tun = __tun_get(tfile);
1407 if (cmd == TUNSETIFF && !tun) {
1408 ifr.ifr_name[IFNAMSIZ-1] = '\0';
1409
1410 ret = tun_set_iff(tfile->net, file, &ifr);
1411
1412 if (ret)
1413 goto unlock;
1414
1415 if (copy_to_user(argp, &ifr, ifreq_len))
1416 ret = -EFAULT;
1417 goto unlock;
1418 }
1419
1420 ret = -EBADFD;
1421 if (!tun)
1422 goto unlock;
1423
1424 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %d\n", cmd);
1425
1426 ret = 0;
1427 switch (cmd) {
1428 case TUNGETIFF:
1429 ret = tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1430 if (ret)
1431 break;
1432
1433 if (copy_to_user(argp, &ifr, ifreq_len))
1434 ret = -EFAULT;
1435 break;
1436
1437 case TUNSETNOCSUM:
1438 /* Disable/Enable checksum */
1439
1440 /* [unimplemented] */
1441 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
1442 arg ? "disabled" : "enabled");
1443 break;
1444
1445 case TUNSETPERSIST:
1446 /* Disable/Enable persist mode */
1447 if (arg)
1448 tun->flags |= TUN_PERSIST;
1449 else
1450 tun->flags &= ~TUN_PERSIST;
1451
1452 tun_debug(KERN_INFO, tun, "persist %s\n",
1453 arg ? "enabled" : "disabled");
1454 break;
1455
1456 case TUNSETOWNER:
1457 /* Set owner of the device */
1458 owner = make_kuid(current_user_ns(), arg);
1459 if (!uid_valid(owner)) {
1460 ret = -EINVAL;
1461 break;
1462 }
1463 tun->owner = owner;
1464 tun_debug(KERN_INFO, tun, "owner set to %d\n",
1465 from_kuid(&init_user_ns, tun->owner));
1466 break;
1467
1468 case TUNSETGROUP:
1469 /* Set group of the device */
1470 group = make_kgid(current_user_ns(), arg);
1471 if (!gid_valid(group)) {
1472 ret = -EINVAL;
1473 break;
1474 }
1475 tun->group = group;
1476 tun_debug(KERN_INFO, tun, "group set to %d\n",
1477 from_kgid(&init_user_ns, tun->group));
1478 break;
1479
1480 case TUNSETLINK:
1481 /* Only allow setting the type when the interface is down */
1482 if (tun->dev->flags & IFF_UP) {
1483 tun_debug(KERN_INFO, tun,
1484 "Linktype set failed because interface is up\n");
1485 ret = -EBUSY;
1486 } else {
1487 tun->dev->type = (int) arg;
1488 tun_debug(KERN_INFO, tun, "linktype set to %d\n",
1489 tun->dev->type);
1490 ret = 0;
1491 }
1492 break;
1493
1494 #ifdef TUN_DEBUG
1495 case TUNSETDEBUG:
1496 tun->debug = arg;
1497 break;
1498 #endif
1499 case TUNSETOFFLOAD:
1500 ret = set_offload(tun, arg);
1501 break;
1502
1503 case TUNSETTXFILTER:
1504 /* Can be set only for TAPs */
1505 ret = -EINVAL;
1506 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1507 break;
1508 ret = update_filter(&tun->txflt, (void __user *)arg);
1509 break;
1510
1511 case SIOCGIFHWADDR:
1512 /* Get hw address */
1513 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
1514 ifr.ifr_hwaddr.sa_family = tun->dev->type;
1515 if (copy_to_user(argp, &ifr, ifreq_len))
1516 ret = -EFAULT;
1517 break;
1518
1519 case SIOCSIFHWADDR:
1520 /* Set hw address */
1521 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
1522 ifr.ifr_hwaddr.sa_data);
1523
1524 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
1525 break;
1526
1527 case TUNGETSNDBUF:
1528 sndbuf = tun->socket.sk->sk_sndbuf;
1529 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
1530 ret = -EFAULT;
1531 break;
1532
1533 case TUNSETSNDBUF:
1534 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
1535 ret = -EFAULT;
1536 break;
1537 }
1538
1539 tun->socket.sk->sk_sndbuf = sndbuf;
1540 break;
1541
1542 case TUNGETVNETHDRSZ:
1543 vnet_hdr_sz = tun->vnet_hdr_sz;
1544 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
1545 ret = -EFAULT;
1546 break;
1547
1548 case TUNSETVNETHDRSZ:
1549 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
1550 ret = -EFAULT;
1551 break;
1552 }
1553 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
1554 ret = -EINVAL;
1555 break;
1556 }
1557
1558 tun->vnet_hdr_sz = vnet_hdr_sz;
1559 break;
1560
1561 case TUNATTACHFILTER:
1562 /* Can be set only for TAPs */
1563 ret = -EINVAL;
1564 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1565 break;
1566 ret = -EFAULT;
1567 if (copy_from_user(&fprog, argp, sizeof(fprog)))
1568 break;
1569
1570 ret = sk_attach_filter(&fprog, tun->socket.sk);
1571 break;
1572
1573 case TUNDETACHFILTER:
1574 /* Can be set only for TAPs */
1575 ret = -EINVAL;
1576 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1577 break;
1578 ret = sk_detach_filter(tun->socket.sk);
1579 break;
1580
1581 default:
1582 ret = -EINVAL;
1583 break;
1584 }
1585
1586 unlock:
1587 rtnl_unlock();
1588 if (tun)
1589 tun_put(tun);
1590 return ret;
1591 }
1592
1593 static long tun_chr_ioctl(struct file *file,
1594 unsigned int cmd, unsigned long arg)
1595 {
1596 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
1597 }
1598
1599 #ifdef CONFIG_COMPAT
1600 static long tun_chr_compat_ioctl(struct file *file,
1601 unsigned int cmd, unsigned long arg)
1602 {
1603 switch (cmd) {
1604 case TUNSETIFF:
1605 case TUNGETIFF:
1606 case TUNSETTXFILTER:
1607 case TUNGETSNDBUF:
1608 case TUNSETSNDBUF:
1609 case SIOCGIFHWADDR:
1610 case SIOCSIFHWADDR:
1611 arg = (unsigned long)compat_ptr(arg);
1612 break;
1613 default:
1614 arg = (compat_ulong_t)arg;
1615 break;
1616 }
1617
1618 /*
1619 * compat_ifreq is shorter than ifreq, so we must not access beyond
1620 * the end of that structure. All fields that are used in this
1621 * driver are compatible though, we don't need to convert the
1622 * contents.
1623 */
1624 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
1625 }
1626 #endif /* CONFIG_COMPAT */
1627
1628 static int tun_chr_fasync(int fd, struct file *file, int on)
1629 {
1630 struct tun_struct *tun = tun_get(file);
1631 int ret;
1632
1633 if (!tun)
1634 return -EBADFD;
1635
1636 tun_debug(KERN_INFO, tun, "tun_chr_fasync %d\n", on);
1637
1638 if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
1639 goto out;
1640
1641 if (on) {
1642 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
1643 if (ret)
1644 goto out;
1645 tun->flags |= TUN_FASYNC;
1646 } else
1647 tun->flags &= ~TUN_FASYNC;
1648 ret = 0;
1649 out:
1650 tun_put(tun);
1651 return ret;
1652 }
1653
1654 static int tun_chr_open(struct inode *inode, struct file * file)
1655 {
1656 struct tun_file *tfile;
1657
1658 DBG1(KERN_INFO, "tunX: tun_chr_open\n");
1659
1660 tfile = kmalloc(sizeof(*tfile), GFP_KERNEL);
1661 if (!tfile)
1662 return -ENOMEM;
1663 atomic_set(&tfile->count, 0);
1664 tfile->tun = NULL;
1665 tfile->net = get_net(current->nsproxy->net_ns);
1666 file->private_data = tfile;
1667 return 0;
1668 }
1669
1670 static int tun_chr_close(struct inode *inode, struct file *file)
1671 {
1672 struct tun_file *tfile = file->private_data;
1673 struct tun_struct *tun;
1674
1675 tun = __tun_get(tfile);
1676 if (tun) {
1677 struct net_device *dev = tun->dev;
1678
1679 tun_debug(KERN_INFO, tun, "tun_chr_close\n");
1680
1681 __tun_detach(tun);
1682
1683 /* If desirable, unregister the netdevice. */
1684 if (!(tun->flags & TUN_PERSIST)) {
1685 rtnl_lock();
1686 if (dev->reg_state == NETREG_REGISTERED)
1687 unregister_netdevice(dev);
1688 rtnl_unlock();
1689 }
1690 }
1691
1692 tun = tfile->tun;
1693 if (tun)
1694 sock_put(tun->socket.sk);
1695
1696 put_net(tfile->net);
1697 kfree(tfile);
1698
1699 return 0;
1700 }
1701
1702 static const struct file_operations tun_fops = {
1703 .owner = THIS_MODULE,
1704 .llseek = no_llseek,
1705 .read = do_sync_read,
1706 .aio_read = tun_chr_aio_read,
1707 .write = do_sync_write,
1708 .aio_write = tun_chr_aio_write,
1709 .poll = tun_chr_poll,
1710 .unlocked_ioctl = tun_chr_ioctl,
1711 #ifdef CONFIG_COMPAT
1712 .compat_ioctl = tun_chr_compat_ioctl,
1713 #endif
1714 .open = tun_chr_open,
1715 .release = tun_chr_close,
1716 .fasync = tun_chr_fasync
1717 };
1718
1719 static struct miscdevice tun_miscdev = {
1720 .minor = TUN_MINOR,
1721 .name = "tun",
1722 .nodename = "net/tun",
1723 .fops = &tun_fops,
1724 };
1725
1726 /* ethtool interface */
1727
1728 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
1729 {
1730 cmd->supported = 0;
1731 cmd->advertising = 0;
1732 ethtool_cmd_speed_set(cmd, SPEED_10);
1733 cmd->duplex = DUPLEX_FULL;
1734 cmd->port = PORT_TP;
1735 cmd->phy_address = 0;
1736 cmd->transceiver = XCVR_INTERNAL;
1737 cmd->autoneg = AUTONEG_DISABLE;
1738 cmd->maxtxpkt = 0;
1739 cmd->maxrxpkt = 0;
1740 return 0;
1741 }
1742
1743 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
1744 {
1745 struct tun_struct *tun = netdev_priv(dev);
1746
1747 strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
1748 strlcpy(info->version, DRV_VERSION, sizeof(info->version));
1749
1750 switch (tun->flags & TUN_TYPE_MASK) {
1751 case TUN_TUN_DEV:
1752 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
1753 break;
1754 case TUN_TAP_DEV:
1755 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
1756 break;
1757 }
1758 }
1759
1760 static u32 tun_get_msglevel(struct net_device *dev)
1761 {
1762 #ifdef TUN_DEBUG
1763 struct tun_struct *tun = netdev_priv(dev);
1764 return tun->debug;
1765 #else
1766 return -EOPNOTSUPP;
1767 #endif
1768 }
1769
1770 static void tun_set_msglevel(struct net_device *dev, u32 value)
1771 {
1772 #ifdef TUN_DEBUG
1773 struct tun_struct *tun = netdev_priv(dev);
1774 tun->debug = value;
1775 #endif
1776 }
1777
1778 static const struct ethtool_ops tun_ethtool_ops = {
1779 .get_settings = tun_get_settings,
1780 .get_drvinfo = tun_get_drvinfo,
1781 .get_msglevel = tun_get_msglevel,
1782 .set_msglevel = tun_set_msglevel,
1783 .get_link = ethtool_op_get_link,
1784 };
1785
1786
1787 static int __init tun_init(void)
1788 {
1789 int ret = 0;
1790
1791 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
1792 pr_info("%s\n", DRV_COPYRIGHT);
1793
1794 ret = rtnl_link_register(&tun_link_ops);
1795 if (ret) {
1796 pr_err("Can't register link_ops\n");
1797 goto err_linkops;
1798 }
1799
1800 ret = misc_register(&tun_miscdev);
1801 if (ret) {
1802 pr_err("Can't register misc device %d\n", TUN_MINOR);
1803 goto err_misc;
1804 }
1805 return 0;
1806 err_misc:
1807 rtnl_link_unregister(&tun_link_ops);
1808 err_linkops:
1809 return ret;
1810 }
1811
1812 static void tun_cleanup(void)
1813 {
1814 misc_deregister(&tun_miscdev);
1815 rtnl_link_unregister(&tun_link_ops);
1816 }
1817
1818 /* Get an underlying socket object from tun file. Returns error unless file is
1819 * attached to a device. The returned object works like a packet socket, it
1820 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
1821 * holding a reference to the file for as long as the socket is in use. */
1822 struct socket *tun_get_socket(struct file *file)
1823 {
1824 struct tun_struct *tun;
1825 if (file->f_op != &tun_fops)
1826 return ERR_PTR(-EINVAL);
1827 tun = tun_get(file);
1828 if (!tun)
1829 return ERR_PTR(-EBADFD);
1830 tun_put(tun);
1831 return &tun->socket;
1832 }
1833 EXPORT_SYMBOL_GPL(tun_get_socket);
1834
1835 module_init(tun_init);
1836 module_exit(tun_cleanup);
1837 MODULE_DESCRIPTION(DRV_DESCRIPTION);
1838 MODULE_AUTHOR(DRV_COPYRIGHT);
1839 MODULE_LICENSE("GPL");
1840 MODULE_ALIAS_MISCDEV(TUN_MINOR);
1841 MODULE_ALIAS("devname:net/tun");
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