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tuntap: move socket to tun_file
[deliverable/linux.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
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 /* A tun_file connects an open character device to a tuntap netdevice. It
113 * also contains all socket related strctures (except sock_fprog and tap_filter)
114 * to serve as one transmit queue for tuntap device. The sock_fprog and
115 * tap_filter were kept in tun_struct since they were used for filtering for the
116 * netdevice not for a specific queue (at least I didn't see the reqirement for
117 * this).
118 */
119 struct tun_file {
120 struct sock sk;
121 struct socket socket;
122 struct socket_wq wq;
123 atomic_t count;
124 struct tun_struct *tun;
125 struct net *net;
126 struct fasync_struct *fasync;
127 /* only used for fasnyc */
128 unsigned int flags;
129 };
130
131 /* Since the socket were moved to tun_file, to preserve the behavior of persist
132 * device, socket fileter, sndbuf and vnet header size were restore when the
133 * file were attached to a persist device.
134 */
135 struct tun_struct {
136 struct tun_file *tfile;
137 unsigned int flags;
138 kuid_t owner;
139 kgid_t group;
140
141 struct net_device *dev;
142 netdev_features_t set_features;
143 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
144 NETIF_F_TSO6|NETIF_F_UFO)
145
146 int vnet_hdr_sz;
147 int sndbuf;
148 struct tap_filter txflt;
149 struct sock_fprog fprog;
150 /* protected by rtnl lock */
151 bool filter_attached;
152 #ifdef TUN_DEBUG
153 int debug;
154 #endif
155 };
156
157 static int tun_attach(struct tun_struct *tun, struct file *file)
158 {
159 struct tun_file *tfile = file->private_data;
160 int err;
161
162 ASSERT_RTNL();
163
164 netif_tx_lock_bh(tun->dev);
165
166 err = -EINVAL;
167 if (tfile->tun)
168 goto out;
169
170 err = -EBUSY;
171 if (tun->tfile)
172 goto out;
173
174 err = 0;
175
176 /* Re-attach filter when attaching to a persist device */
177 if (tun->filter_attached == true) {
178 err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
179 if (!err)
180 goto out;
181 }
182 tfile->tun = tun;
183 tfile->socket.sk->sk_sndbuf = tun->sndbuf;
184 tun->tfile = tfile;
185 netif_carrier_on(tun->dev);
186 dev_hold(tun->dev);
187 sock_hold(&tfile->sk);
188 atomic_inc(&tfile->count);
189
190 out:
191 netif_tx_unlock_bh(tun->dev);
192 return err;
193 }
194
195 static void __tun_detach(struct tun_struct *tun)
196 {
197 struct tun_file *tfile = tun->tfile;
198 /* Detach from net device */
199 netif_tx_lock_bh(tun->dev);
200 netif_carrier_off(tun->dev);
201 tun->tfile = NULL;
202 tfile->tun = NULL;
203 netif_tx_unlock_bh(tun->dev);
204
205 /* Drop read queue */
206 skb_queue_purge(&tfile->socket.sk->sk_receive_queue);
207
208 /* Drop the extra count on the net device */
209 dev_put(tun->dev);
210 }
211
212 static void tun_detach(struct tun_struct *tun)
213 {
214 rtnl_lock();
215 __tun_detach(tun);
216 rtnl_unlock();
217 }
218
219 static struct tun_struct *__tun_get(struct tun_file *tfile)
220 {
221 struct tun_struct *tun = NULL;
222
223 if (atomic_inc_not_zero(&tfile->count))
224 tun = tfile->tun;
225
226 return tun;
227 }
228
229 static struct tun_struct *tun_get(struct file *file)
230 {
231 return __tun_get(file->private_data);
232 }
233
234 static void tun_put(struct tun_struct *tun)
235 {
236 struct tun_file *tfile = tun->tfile;
237
238 if (atomic_dec_and_test(&tfile->count))
239 tun_detach(tfile->tun);
240 }
241
242 /* TAP filtering */
243 static void addr_hash_set(u32 *mask, const u8 *addr)
244 {
245 int n = ether_crc(ETH_ALEN, addr) >> 26;
246 mask[n >> 5] |= (1 << (n & 31));
247 }
248
249 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
250 {
251 int n = ether_crc(ETH_ALEN, addr) >> 26;
252 return mask[n >> 5] & (1 << (n & 31));
253 }
254
255 static int update_filter(struct tap_filter *filter, void __user *arg)
256 {
257 struct { u8 u[ETH_ALEN]; } *addr;
258 struct tun_filter uf;
259 int err, alen, n, nexact;
260
261 if (copy_from_user(&uf, arg, sizeof(uf)))
262 return -EFAULT;
263
264 if (!uf.count) {
265 /* Disabled */
266 filter->count = 0;
267 return 0;
268 }
269
270 alen = ETH_ALEN * uf.count;
271 addr = kmalloc(alen, GFP_KERNEL);
272 if (!addr)
273 return -ENOMEM;
274
275 if (copy_from_user(addr, arg + sizeof(uf), alen)) {
276 err = -EFAULT;
277 goto done;
278 }
279
280 /* The filter is updated without holding any locks. Which is
281 * perfectly safe. We disable it first and in the worst
282 * case we'll accept a few undesired packets. */
283 filter->count = 0;
284 wmb();
285
286 /* Use first set of addresses as an exact filter */
287 for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
288 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
289
290 nexact = n;
291
292 /* Remaining multicast addresses are hashed,
293 * unicast will leave the filter disabled. */
294 memset(filter->mask, 0, sizeof(filter->mask));
295 for (; n < uf.count; n++) {
296 if (!is_multicast_ether_addr(addr[n].u)) {
297 err = 0; /* no filter */
298 goto done;
299 }
300 addr_hash_set(filter->mask, addr[n].u);
301 }
302
303 /* For ALLMULTI just set the mask to all ones.
304 * This overrides the mask populated above. */
305 if ((uf.flags & TUN_FLT_ALLMULTI))
306 memset(filter->mask, ~0, sizeof(filter->mask));
307
308 /* Now enable the filter */
309 wmb();
310 filter->count = nexact;
311
312 /* Return the number of exact filters */
313 err = nexact;
314
315 done:
316 kfree(addr);
317 return err;
318 }
319
320 /* Returns: 0 - drop, !=0 - accept */
321 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
322 {
323 /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
324 * at this point. */
325 struct ethhdr *eh = (struct ethhdr *) skb->data;
326 int i;
327
328 /* Exact match */
329 for (i = 0; i < filter->count; i++)
330 if (ether_addr_equal(eh->h_dest, filter->addr[i]))
331 return 1;
332
333 /* Inexact match (multicast only) */
334 if (is_multicast_ether_addr(eh->h_dest))
335 return addr_hash_test(filter->mask, eh->h_dest);
336
337 return 0;
338 }
339
340 /*
341 * Checks whether the packet is accepted or not.
342 * Returns: 0 - drop, !=0 - accept
343 */
344 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
345 {
346 if (!filter->count)
347 return 1;
348
349 return run_filter(filter, skb);
350 }
351
352 /* Network device part of the driver */
353
354 static const struct ethtool_ops tun_ethtool_ops;
355
356 /* Net device detach from fd. */
357 static void tun_net_uninit(struct net_device *dev)
358 {
359 struct tun_struct *tun = netdev_priv(dev);
360 struct tun_file *tfile = tun->tfile;
361
362 /* Inform the methods they need to stop using the dev.
363 */
364 if (tfile) {
365 wake_up_all(&tfile->wq.wait);
366 if (atomic_dec_and_test(&tfile->count))
367 __tun_detach(tun);
368 }
369 }
370
371 /* Net device open. */
372 static int tun_net_open(struct net_device *dev)
373 {
374 netif_start_queue(dev);
375 return 0;
376 }
377
378 /* Net device close. */
379 static int tun_net_close(struct net_device *dev)
380 {
381 netif_stop_queue(dev);
382 return 0;
383 }
384
385 /* Net device start xmit */
386 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
387 {
388 struct tun_struct *tun = netdev_priv(dev);
389 struct tun_file *tfile = tun->tfile;
390
391 tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
392
393 /* Drop packet if interface is not attached */
394 if (!tfile)
395 goto drop;
396
397 /* Drop if the filter does not like it.
398 * This is a noop if the filter is disabled.
399 * Filter can be enabled only for the TAP devices. */
400 if (!check_filter(&tun->txflt, skb))
401 goto drop;
402
403 if (tfile->socket.sk->sk_filter &&
404 sk_filter(tfile->socket.sk, skb))
405 goto drop;
406
407 if (skb_queue_len(&tfile->socket.sk->sk_receive_queue)
408 >= dev->tx_queue_len) {
409 if (!(tun->flags & TUN_ONE_QUEUE)) {
410 /* Normal queueing mode. */
411 /* Packet scheduler handles dropping of further packets. */
412 netif_stop_queue(dev);
413
414 /* We won't see all dropped packets individually, so overrun
415 * error is more appropriate. */
416 dev->stats.tx_fifo_errors++;
417 } else {
418 /* Single queue mode.
419 * Driver handles dropping of all packets itself. */
420 goto drop;
421 }
422 }
423
424 /* Orphan the skb - required as we might hang on to it
425 * for indefinite time. */
426 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
427 goto drop;
428 skb_orphan(skb);
429
430 /* Enqueue packet */
431 skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb);
432
433 /* Notify and wake up reader process */
434 if (tfile->flags & TUN_FASYNC)
435 kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
436 wake_up_interruptible_poll(&tfile->wq.wait, POLLIN |
437 POLLRDNORM | POLLRDBAND);
438 return NETDEV_TX_OK;
439
440 drop:
441 dev->stats.tx_dropped++;
442 kfree_skb(skb);
443 return NETDEV_TX_OK;
444 }
445
446 static void tun_net_mclist(struct net_device *dev)
447 {
448 /*
449 * This callback is supposed to deal with mc filter in
450 * _rx_ path and has nothing to do with the _tx_ path.
451 * In rx path we always accept everything userspace gives us.
452 */
453 }
454
455 #define MIN_MTU 68
456 #define MAX_MTU 65535
457
458 static int
459 tun_net_change_mtu(struct net_device *dev, int new_mtu)
460 {
461 if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
462 return -EINVAL;
463 dev->mtu = new_mtu;
464 return 0;
465 }
466
467 static netdev_features_t tun_net_fix_features(struct net_device *dev,
468 netdev_features_t features)
469 {
470 struct tun_struct *tun = netdev_priv(dev);
471
472 return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
473 }
474 #ifdef CONFIG_NET_POLL_CONTROLLER
475 static void tun_poll_controller(struct net_device *dev)
476 {
477 /*
478 * Tun only receives frames when:
479 * 1) the char device endpoint gets data from user space
480 * 2) the tun socket gets a sendmsg call from user space
481 * Since both of those are syncronous operations, we are guaranteed
482 * never to have pending data when we poll for it
483 * so theres nothing to do here but return.
484 * We need this though so netpoll recognizes us as an interface that
485 * supports polling, which enables bridge devices in virt setups to
486 * still use netconsole
487 */
488 return;
489 }
490 #endif
491 static const struct net_device_ops tun_netdev_ops = {
492 .ndo_uninit = tun_net_uninit,
493 .ndo_open = tun_net_open,
494 .ndo_stop = tun_net_close,
495 .ndo_start_xmit = tun_net_xmit,
496 .ndo_change_mtu = tun_net_change_mtu,
497 .ndo_fix_features = tun_net_fix_features,
498 #ifdef CONFIG_NET_POLL_CONTROLLER
499 .ndo_poll_controller = tun_poll_controller,
500 #endif
501 };
502
503 static const struct net_device_ops tap_netdev_ops = {
504 .ndo_uninit = tun_net_uninit,
505 .ndo_open = tun_net_open,
506 .ndo_stop = tun_net_close,
507 .ndo_start_xmit = tun_net_xmit,
508 .ndo_change_mtu = tun_net_change_mtu,
509 .ndo_fix_features = tun_net_fix_features,
510 .ndo_set_rx_mode = tun_net_mclist,
511 .ndo_set_mac_address = eth_mac_addr,
512 .ndo_validate_addr = eth_validate_addr,
513 #ifdef CONFIG_NET_POLL_CONTROLLER
514 .ndo_poll_controller = tun_poll_controller,
515 #endif
516 };
517
518 /* Initialize net device. */
519 static void tun_net_init(struct net_device *dev)
520 {
521 struct tun_struct *tun = netdev_priv(dev);
522
523 switch (tun->flags & TUN_TYPE_MASK) {
524 case TUN_TUN_DEV:
525 dev->netdev_ops = &tun_netdev_ops;
526
527 /* Point-to-Point TUN Device */
528 dev->hard_header_len = 0;
529 dev->addr_len = 0;
530 dev->mtu = 1500;
531
532 /* Zero header length */
533 dev->type = ARPHRD_NONE;
534 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
535 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */
536 break;
537
538 case TUN_TAP_DEV:
539 dev->netdev_ops = &tap_netdev_ops;
540 /* Ethernet TAP Device */
541 ether_setup(dev);
542 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
543
544 eth_hw_addr_random(dev);
545
546 dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */
547 break;
548 }
549 }
550
551 /* Character device part */
552
553 /* Poll */
554 static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
555 {
556 struct tun_file *tfile = file->private_data;
557 struct tun_struct *tun = __tun_get(tfile);
558 struct sock *sk;
559 unsigned int mask = 0;
560
561 if (!tun)
562 return POLLERR;
563
564 sk = tfile->socket.sk;
565
566 tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
567
568 poll_wait(file, &tfile->wq.wait, wait);
569
570 if (!skb_queue_empty(&sk->sk_receive_queue))
571 mask |= POLLIN | POLLRDNORM;
572
573 if (sock_writeable(sk) ||
574 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
575 sock_writeable(sk)))
576 mask |= POLLOUT | POLLWRNORM;
577
578 if (tun->dev->reg_state != NETREG_REGISTERED)
579 mask = POLLERR;
580
581 tun_put(tun);
582 return mask;
583 }
584
585 /* prepad is the amount to reserve at front. len is length after that.
586 * linear is a hint as to how much to copy (usually headers). */
587 static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
588 size_t prepad, size_t len,
589 size_t linear, int noblock)
590 {
591 struct sock *sk = tfile->socket.sk;
592 struct sk_buff *skb;
593 int err;
594
595 /* Under a page? Don't bother with paged skb. */
596 if (prepad + len < PAGE_SIZE || !linear)
597 linear = len;
598
599 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
600 &err);
601 if (!skb)
602 return ERR_PTR(err);
603
604 skb_reserve(skb, prepad);
605 skb_put(skb, linear);
606 skb->data_len = len - linear;
607 skb->len += len - linear;
608
609 return skb;
610 }
611
612 /* set skb frags from iovec, this can move to core network code for reuse */
613 static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from,
614 int offset, size_t count)
615 {
616 int len = iov_length(from, count) - offset;
617 int copy = skb_headlen(skb);
618 int size, offset1 = 0;
619 int i = 0;
620
621 /* Skip over from offset */
622 while (count && (offset >= from->iov_len)) {
623 offset -= from->iov_len;
624 ++from;
625 --count;
626 }
627
628 /* copy up to skb headlen */
629 while (count && (copy > 0)) {
630 size = min_t(unsigned int, copy, from->iov_len - offset);
631 if (copy_from_user(skb->data + offset1, from->iov_base + offset,
632 size))
633 return -EFAULT;
634 if (copy > size) {
635 ++from;
636 --count;
637 offset = 0;
638 } else
639 offset += size;
640 copy -= size;
641 offset1 += size;
642 }
643
644 if (len == offset1)
645 return 0;
646
647 while (count--) {
648 struct page *page[MAX_SKB_FRAGS];
649 int num_pages;
650 unsigned long base;
651 unsigned long truesize;
652
653 len = from->iov_len - offset;
654 if (!len) {
655 offset = 0;
656 ++from;
657 continue;
658 }
659 base = (unsigned long)from->iov_base + offset;
660 size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT;
661 if (i + size > MAX_SKB_FRAGS)
662 return -EMSGSIZE;
663 num_pages = get_user_pages_fast(base, size, 0, &page[i]);
664 if (num_pages != size) {
665 for (i = 0; i < num_pages; i++)
666 put_page(page[i]);
667 return -EFAULT;
668 }
669 truesize = size * PAGE_SIZE;
670 skb->data_len += len;
671 skb->len += len;
672 skb->truesize += truesize;
673 atomic_add(truesize, &skb->sk->sk_wmem_alloc);
674 while (len) {
675 int off = base & ~PAGE_MASK;
676 int size = min_t(int, len, PAGE_SIZE - off);
677 __skb_fill_page_desc(skb, i, page[i], off, size);
678 skb_shinfo(skb)->nr_frags++;
679 /* increase sk_wmem_alloc */
680 base += size;
681 len -= size;
682 i++;
683 }
684 offset = 0;
685 ++from;
686 }
687 return 0;
688 }
689
690 /* Get packet from user space buffer */
691 static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
692 void *msg_control, const struct iovec *iv,
693 size_t total_len, size_t count, int noblock)
694 {
695 struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
696 struct sk_buff *skb;
697 size_t len = total_len, align = NET_SKB_PAD;
698 struct virtio_net_hdr gso = { 0 };
699 int offset = 0;
700 int copylen;
701 bool zerocopy = false;
702 int err;
703
704 if (!(tun->flags & TUN_NO_PI)) {
705 if ((len -= sizeof(pi)) > total_len)
706 return -EINVAL;
707
708 if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
709 return -EFAULT;
710 offset += sizeof(pi);
711 }
712
713 if (tun->flags & TUN_VNET_HDR) {
714 if ((len -= tun->vnet_hdr_sz) > total_len)
715 return -EINVAL;
716
717 if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
718 return -EFAULT;
719
720 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
721 gso.csum_start + gso.csum_offset + 2 > gso.hdr_len)
722 gso.hdr_len = gso.csum_start + gso.csum_offset + 2;
723
724 if (gso.hdr_len > len)
725 return -EINVAL;
726 offset += tun->vnet_hdr_sz;
727 }
728
729 if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
730 align += NET_IP_ALIGN;
731 if (unlikely(len < ETH_HLEN ||
732 (gso.hdr_len && gso.hdr_len < ETH_HLEN)))
733 return -EINVAL;
734 }
735
736 if (msg_control)
737 zerocopy = true;
738
739 if (zerocopy) {
740 /* Userspace may produce vectors with count greater than
741 * MAX_SKB_FRAGS, so we need to linearize parts of the skb
742 * to let the rest of data to be fit in the frags.
743 */
744 if (count > MAX_SKB_FRAGS) {
745 copylen = iov_length(iv, count - MAX_SKB_FRAGS);
746 if (copylen < offset)
747 copylen = 0;
748 else
749 copylen -= offset;
750 } else
751 copylen = 0;
752 /* There are 256 bytes to be copied in skb, so there is enough
753 * room for skb expand head in case it is used.
754 * The rest of the buffer is mapped from userspace.
755 */
756 if (copylen < gso.hdr_len)
757 copylen = gso.hdr_len;
758 if (!copylen)
759 copylen = GOODCOPY_LEN;
760 } else
761 copylen = len;
762
763 skb = tun_alloc_skb(tfile, align, copylen, gso.hdr_len, noblock);
764 if (IS_ERR(skb)) {
765 if (PTR_ERR(skb) != -EAGAIN)
766 tun->dev->stats.rx_dropped++;
767 return PTR_ERR(skb);
768 }
769
770 if (zerocopy)
771 err = zerocopy_sg_from_iovec(skb, iv, offset, count);
772 else
773 err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len);
774
775 if (err) {
776 tun->dev->stats.rx_dropped++;
777 kfree_skb(skb);
778 return -EFAULT;
779 }
780
781 if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
782 if (!skb_partial_csum_set(skb, gso.csum_start,
783 gso.csum_offset)) {
784 tun->dev->stats.rx_frame_errors++;
785 kfree_skb(skb);
786 return -EINVAL;
787 }
788 }
789
790 switch (tun->flags & TUN_TYPE_MASK) {
791 case TUN_TUN_DEV:
792 if (tun->flags & TUN_NO_PI) {
793 switch (skb->data[0] & 0xf0) {
794 case 0x40:
795 pi.proto = htons(ETH_P_IP);
796 break;
797 case 0x60:
798 pi.proto = htons(ETH_P_IPV6);
799 break;
800 default:
801 tun->dev->stats.rx_dropped++;
802 kfree_skb(skb);
803 return -EINVAL;
804 }
805 }
806
807 skb_reset_mac_header(skb);
808 skb->protocol = pi.proto;
809 skb->dev = tun->dev;
810 break;
811 case TUN_TAP_DEV:
812 skb->protocol = eth_type_trans(skb, tun->dev);
813 break;
814 }
815
816 if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
817 pr_debug("GSO!\n");
818 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
819 case VIRTIO_NET_HDR_GSO_TCPV4:
820 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
821 break;
822 case VIRTIO_NET_HDR_GSO_TCPV6:
823 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
824 break;
825 case VIRTIO_NET_HDR_GSO_UDP:
826 skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
827 break;
828 default:
829 tun->dev->stats.rx_frame_errors++;
830 kfree_skb(skb);
831 return -EINVAL;
832 }
833
834 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
835 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
836
837 skb_shinfo(skb)->gso_size = gso.gso_size;
838 if (skb_shinfo(skb)->gso_size == 0) {
839 tun->dev->stats.rx_frame_errors++;
840 kfree_skb(skb);
841 return -EINVAL;
842 }
843
844 /* Header must be checked, and gso_segs computed. */
845 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
846 skb_shinfo(skb)->gso_segs = 0;
847 }
848
849 /* copy skb_ubuf_info for callback when skb has no error */
850 if (zerocopy) {
851 skb_shinfo(skb)->destructor_arg = msg_control;
852 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
853 }
854
855 netif_rx_ni(skb);
856
857 tun->dev->stats.rx_packets++;
858 tun->dev->stats.rx_bytes += len;
859
860 return total_len;
861 }
862
863 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
864 unsigned long count, loff_t pos)
865 {
866 struct file *file = iocb->ki_filp;
867 struct tun_struct *tun = tun_get(file);
868 struct tun_file *tfile = file->private_data;
869 ssize_t result;
870
871 if (!tun)
872 return -EBADFD;
873
874 tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count);
875
876 result = tun_get_user(tun, tfile, NULL, iv, iov_length(iv, count),
877 count, file->f_flags & O_NONBLOCK);
878
879 tun_put(tun);
880 return result;
881 }
882
883 /* Put packet to the user space buffer */
884 static ssize_t tun_put_user(struct tun_struct *tun,
885 struct tun_file *tfile,
886 struct sk_buff *skb,
887 const struct iovec *iv, int len)
888 {
889 struct tun_pi pi = { 0, skb->protocol };
890 ssize_t total = 0;
891
892 if (!(tun->flags & TUN_NO_PI)) {
893 if ((len -= sizeof(pi)) < 0)
894 return -EINVAL;
895
896 if (len < skb->len) {
897 /* Packet will be striped */
898 pi.flags |= TUN_PKT_STRIP;
899 }
900
901 if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi)))
902 return -EFAULT;
903 total += sizeof(pi);
904 }
905
906 if (tun->flags & TUN_VNET_HDR) {
907 struct virtio_net_hdr gso = { 0 }; /* no info leak */
908 if ((len -= tun->vnet_hdr_sz) < 0)
909 return -EINVAL;
910
911 if (skb_is_gso(skb)) {
912 struct skb_shared_info *sinfo = skb_shinfo(skb);
913
914 /* This is a hint as to how much should be linear. */
915 gso.hdr_len = skb_headlen(skb);
916 gso.gso_size = sinfo->gso_size;
917 if (sinfo->gso_type & SKB_GSO_TCPV4)
918 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
919 else if (sinfo->gso_type & SKB_GSO_TCPV6)
920 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
921 else if (sinfo->gso_type & SKB_GSO_UDP)
922 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
923 else {
924 pr_err("unexpected GSO type: "
925 "0x%x, gso_size %d, hdr_len %d\n",
926 sinfo->gso_type, gso.gso_size,
927 gso.hdr_len);
928 print_hex_dump(KERN_ERR, "tun: ",
929 DUMP_PREFIX_NONE,
930 16, 1, skb->head,
931 min((int)gso.hdr_len, 64), true);
932 WARN_ON_ONCE(1);
933 return -EINVAL;
934 }
935 if (sinfo->gso_type & SKB_GSO_TCP_ECN)
936 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
937 } else
938 gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
939
940 if (skb->ip_summed == CHECKSUM_PARTIAL) {
941 gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
942 gso.csum_start = skb_checksum_start_offset(skb);
943 gso.csum_offset = skb->csum_offset;
944 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
945 gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
946 } /* else everything is zero */
947
948 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total,
949 sizeof(gso))))
950 return -EFAULT;
951 total += tun->vnet_hdr_sz;
952 }
953
954 len = min_t(int, skb->len, len);
955
956 skb_copy_datagram_const_iovec(skb, 0, iv, total, len);
957 total += skb->len;
958
959 tun->dev->stats.tx_packets++;
960 tun->dev->stats.tx_bytes += len;
961
962 return total;
963 }
964
965 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
966 struct kiocb *iocb, const struct iovec *iv,
967 ssize_t len, int noblock)
968 {
969 DECLARE_WAITQUEUE(wait, current);
970 struct sk_buff *skb;
971 ssize_t ret = 0;
972
973 tun_debug(KERN_INFO, tun, "tun_chr_read\n");
974
975 if (unlikely(!noblock))
976 add_wait_queue(&tfile->wq.wait, &wait);
977 while (len) {
978 current->state = TASK_INTERRUPTIBLE;
979
980 /* Read frames from the queue */
981 if (!(skb = skb_dequeue(&tfile->socket.sk->sk_receive_queue))) {
982 if (noblock) {
983 ret = -EAGAIN;
984 break;
985 }
986 if (signal_pending(current)) {
987 ret = -ERESTARTSYS;
988 break;
989 }
990 if (tun->dev->reg_state != NETREG_REGISTERED) {
991 ret = -EIO;
992 break;
993 }
994
995 /* Nothing to read, let's sleep */
996 schedule();
997 continue;
998 }
999 netif_wake_queue(tun->dev);
1000
1001 ret = tun_put_user(tun, tfile, skb, iv, len);
1002 kfree_skb(skb);
1003 break;
1004 }
1005
1006 current->state = TASK_RUNNING;
1007 if (unlikely(!noblock))
1008 remove_wait_queue(&tfile->wq.wait, &wait);
1009
1010 return ret;
1011 }
1012
1013 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
1014 unsigned long count, loff_t pos)
1015 {
1016 struct file *file = iocb->ki_filp;
1017 struct tun_file *tfile = file->private_data;
1018 struct tun_struct *tun = __tun_get(tfile);
1019 ssize_t len, ret;
1020
1021 if (!tun)
1022 return -EBADFD;
1023 len = iov_length(iv, count);
1024 if (len < 0) {
1025 ret = -EINVAL;
1026 goto out;
1027 }
1028
1029 ret = tun_do_read(tun, tfile, iocb, iv, len,
1030 file->f_flags & O_NONBLOCK);
1031 ret = min_t(ssize_t, ret, len);
1032 out:
1033 tun_put(tun);
1034 return ret;
1035 }
1036
1037 static void tun_setup(struct net_device *dev)
1038 {
1039 struct tun_struct *tun = netdev_priv(dev);
1040
1041 tun->owner = INVALID_UID;
1042 tun->group = INVALID_GID;
1043
1044 dev->ethtool_ops = &tun_ethtool_ops;
1045 dev->destructor = free_netdev;
1046 }
1047
1048 /* Trivial set of netlink ops to allow deleting tun or tap
1049 * device with netlink.
1050 */
1051 static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
1052 {
1053 return -EINVAL;
1054 }
1055
1056 static struct rtnl_link_ops tun_link_ops __read_mostly = {
1057 .kind = DRV_NAME,
1058 .priv_size = sizeof(struct tun_struct),
1059 .setup = tun_setup,
1060 .validate = tun_validate,
1061 };
1062
1063 static void tun_sock_write_space(struct sock *sk)
1064 {
1065 struct tun_file *tfile;
1066 wait_queue_head_t *wqueue;
1067
1068 if (!sock_writeable(sk))
1069 return;
1070
1071 if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
1072 return;
1073
1074 wqueue = sk_sleep(sk);
1075 if (wqueue && waitqueue_active(wqueue))
1076 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
1077 POLLWRNORM | POLLWRBAND);
1078
1079 tfile = container_of(sk, struct tun_file, sk);
1080 kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
1081 }
1082
1083 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock,
1084 struct msghdr *m, size_t total_len)
1085 {
1086 int ret;
1087 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1088 struct tun_struct *tun = __tun_get(tfile);
1089
1090 if (!tun)
1091 return -EBADFD;
1092
1093 ret = tun_get_user(tun, tfile, m->msg_control, m->msg_iov, total_len,
1094 m->msg_iovlen, m->msg_flags & MSG_DONTWAIT);
1095 tun_put(tun);
1096 return ret;
1097 }
1098
1099
1100 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
1101 struct msghdr *m, size_t total_len,
1102 int flags)
1103 {
1104 struct tun_file *tfile = container_of(sock, struct tun_file, socket);
1105 struct tun_struct *tun = __tun_get(tfile);
1106 int ret;
1107
1108 if (!tun)
1109 return -EBADFD;
1110
1111 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
1112 return -EINVAL;
1113 ret = tun_do_read(tun, tfile, iocb, m->msg_iov, total_len,
1114 flags & MSG_DONTWAIT);
1115 if (ret > total_len) {
1116 m->msg_flags |= MSG_TRUNC;
1117 ret = flags & MSG_TRUNC ? ret : total_len;
1118 }
1119 tun_put(tun);
1120 return ret;
1121 }
1122
1123 static int tun_release(struct socket *sock)
1124 {
1125 if (sock->sk)
1126 sock_put(sock->sk);
1127 return 0;
1128 }
1129
1130 /* Ops structure to mimic raw sockets with tun */
1131 static const struct proto_ops tun_socket_ops = {
1132 .sendmsg = tun_sendmsg,
1133 .recvmsg = tun_recvmsg,
1134 .release = tun_release,
1135 };
1136
1137 static struct proto tun_proto = {
1138 .name = "tun",
1139 .owner = THIS_MODULE,
1140 .obj_size = sizeof(struct tun_file),
1141 };
1142
1143 static int tun_flags(struct tun_struct *tun)
1144 {
1145 int flags = 0;
1146
1147 if (tun->flags & TUN_TUN_DEV)
1148 flags |= IFF_TUN;
1149 else
1150 flags |= IFF_TAP;
1151
1152 if (tun->flags & TUN_NO_PI)
1153 flags |= IFF_NO_PI;
1154
1155 if (tun->flags & TUN_ONE_QUEUE)
1156 flags |= IFF_ONE_QUEUE;
1157
1158 if (tun->flags & TUN_VNET_HDR)
1159 flags |= IFF_VNET_HDR;
1160
1161 return flags;
1162 }
1163
1164 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1165 char *buf)
1166 {
1167 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1168 return sprintf(buf, "0x%x\n", tun_flags(tun));
1169 }
1170
1171 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1172 char *buf)
1173 {
1174 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1175 return uid_valid(tun->owner)?
1176 sprintf(buf, "%u\n",
1177 from_kuid_munged(current_user_ns(), tun->owner)):
1178 sprintf(buf, "-1\n");
1179 }
1180
1181 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1182 char *buf)
1183 {
1184 struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1185 return gid_valid(tun->group) ?
1186 sprintf(buf, "%u\n",
1187 from_kgid_munged(current_user_ns(), tun->group)):
1188 sprintf(buf, "-1\n");
1189 }
1190
1191 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1192 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1193 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1194
1195 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1196 {
1197 struct tun_struct *tun;
1198 struct tun_file *tfile = file->private_data;
1199 struct net_device *dev;
1200 int err;
1201
1202 dev = __dev_get_by_name(net, ifr->ifr_name);
1203 if (dev) {
1204 const struct cred *cred = current_cred();
1205
1206 if (ifr->ifr_flags & IFF_TUN_EXCL)
1207 return -EBUSY;
1208 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1209 tun = netdev_priv(dev);
1210 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1211 tun = netdev_priv(dev);
1212 else
1213 return -EINVAL;
1214
1215 if (((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
1216 (gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
1217 !capable(CAP_NET_ADMIN))
1218 return -EPERM;
1219 err = security_tun_dev_attach(tfile->socket.sk);
1220 if (err < 0)
1221 return err;
1222
1223 err = tun_attach(tun, file);
1224 if (err < 0)
1225 return err;
1226 }
1227 else {
1228 char *name;
1229 unsigned long flags = 0;
1230
1231 if (!capable(CAP_NET_ADMIN))
1232 return -EPERM;
1233 err = security_tun_dev_create();
1234 if (err < 0)
1235 return err;
1236
1237 /* Set dev type */
1238 if (ifr->ifr_flags & IFF_TUN) {
1239 /* TUN device */
1240 flags |= TUN_TUN_DEV;
1241 name = "tun%d";
1242 } else if (ifr->ifr_flags & IFF_TAP) {
1243 /* TAP device */
1244 flags |= TUN_TAP_DEV;
1245 name = "tap%d";
1246 } else
1247 return -EINVAL;
1248
1249 if (*ifr->ifr_name)
1250 name = ifr->ifr_name;
1251
1252 dev = alloc_netdev(sizeof(struct tun_struct), name,
1253 tun_setup);
1254 if (!dev)
1255 return -ENOMEM;
1256
1257 dev_net_set(dev, net);
1258 dev->rtnl_link_ops = &tun_link_ops;
1259
1260 tun = netdev_priv(dev);
1261 tun->dev = dev;
1262 tun->flags = flags;
1263 tun->txflt.count = 0;
1264 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1265
1266 tun->filter_attached = false;
1267 tun->sndbuf = tfile->socket.sk->sk_sndbuf;
1268
1269 security_tun_dev_post_create(&tfile->sk);
1270
1271 tun_net_init(dev);
1272
1273 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1274 TUN_USER_FEATURES;
1275 dev->features = dev->hw_features;
1276
1277 err = register_netdevice(tun->dev);
1278 if (err < 0)
1279 goto err_free_dev;
1280
1281 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) ||
1282 device_create_file(&tun->dev->dev, &dev_attr_owner) ||
1283 device_create_file(&tun->dev->dev, &dev_attr_group))
1284 pr_err("Failed to create tun sysfs files\n");
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_dev:
1318 free_netdev(dev);
1319 failed:
1320 return err;
1321 }
1322
1323 static int tun_get_iff(struct net *net, struct tun_struct *tun,
1324 struct ifreq *ifr)
1325 {
1326 tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1327
1328 strcpy(ifr->ifr_name, tun->dev->name);
1329
1330 ifr->ifr_flags = tun_flags(tun);
1331
1332 return 0;
1333 }
1334
1335 /* This is like a cut-down ethtool ops, except done via tun fd so no
1336 * privs required. */
1337 static int set_offload(struct tun_struct *tun, unsigned long arg)
1338 {
1339 netdev_features_t features = 0;
1340
1341 if (arg & TUN_F_CSUM) {
1342 features |= NETIF_F_HW_CSUM;
1343 arg &= ~TUN_F_CSUM;
1344
1345 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1346 if (arg & TUN_F_TSO_ECN) {
1347 features |= NETIF_F_TSO_ECN;
1348 arg &= ~TUN_F_TSO_ECN;
1349 }
1350 if (arg & TUN_F_TSO4)
1351 features |= NETIF_F_TSO;
1352 if (arg & TUN_F_TSO6)
1353 features |= NETIF_F_TSO6;
1354 arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1355 }
1356
1357 if (arg & TUN_F_UFO) {
1358 features |= NETIF_F_UFO;
1359 arg &= ~TUN_F_UFO;
1360 }
1361 }
1362
1363 /* This gives the user a way to test for new features in future by
1364 * trying to set them. */
1365 if (arg)
1366 return -EINVAL;
1367
1368 tun->set_features = features;
1369 netdev_update_features(tun->dev);
1370
1371 return 0;
1372 }
1373
1374 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1375 unsigned long arg, int ifreq_len)
1376 {
1377 struct tun_file *tfile = file->private_data;
1378 struct tun_struct *tun;
1379 void __user* argp = (void __user*)arg;
1380 struct ifreq ifr;
1381 kuid_t owner;
1382 kgid_t group;
1383 int sndbuf;
1384 int vnet_hdr_sz;
1385 int ret;
1386
1387 if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89) {
1388 if (copy_from_user(&ifr, argp, ifreq_len))
1389 return -EFAULT;
1390 } else {
1391 memset(&ifr, 0, sizeof(ifr));
1392 }
1393 if (cmd == TUNGETFEATURES) {
1394 /* Currently this just means: "what IFF flags are valid?".
1395 * This is needed because we never checked for invalid flags on
1396 * TUNSETIFF. */
1397 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
1398 IFF_VNET_HDR,
1399 (unsigned int __user*)argp);
1400 }
1401
1402 rtnl_lock();
1403
1404 tun = __tun_get(tfile);
1405 if (cmd == TUNSETIFF && !tun) {
1406 ifr.ifr_name[IFNAMSIZ-1] = '\0';
1407
1408 ret = tun_set_iff(tfile->net, file, &ifr);
1409
1410 if (ret)
1411 goto unlock;
1412
1413 if (copy_to_user(argp, &ifr, ifreq_len))
1414 ret = -EFAULT;
1415 goto unlock;
1416 }
1417
1418 ret = -EBADFD;
1419 if (!tun)
1420 goto unlock;
1421
1422 tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
1423
1424 ret = 0;
1425 switch (cmd) {
1426 case TUNGETIFF:
1427 ret = tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1428 if (ret)
1429 break;
1430
1431 if (copy_to_user(argp, &ifr, ifreq_len))
1432 ret = -EFAULT;
1433 break;
1434
1435 case TUNSETNOCSUM:
1436 /* Disable/Enable checksum */
1437
1438 /* [unimplemented] */
1439 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
1440 arg ? "disabled" : "enabled");
1441 break;
1442
1443 case TUNSETPERSIST:
1444 /* Disable/Enable persist mode. Keep an extra reference to the
1445 * module to prevent the module being unprobed.
1446 */
1447 if (arg) {
1448 tun->flags |= TUN_PERSIST;
1449 __module_get(THIS_MODULE);
1450 } else {
1451 tun->flags &= ~TUN_PERSIST;
1452 module_put(THIS_MODULE);
1453 }
1454
1455 tun_debug(KERN_INFO, tun, "persist %s\n",
1456 arg ? "enabled" : "disabled");
1457 break;
1458
1459 case TUNSETOWNER:
1460 /* Set owner of the device */
1461 owner = make_kuid(current_user_ns(), arg);
1462 if (!uid_valid(owner)) {
1463 ret = -EINVAL;
1464 break;
1465 }
1466 tun->owner = owner;
1467 tun_debug(KERN_INFO, tun, "owner set to %u\n",
1468 from_kuid(&init_user_ns, tun->owner));
1469 break;
1470
1471 case TUNSETGROUP:
1472 /* Set group of the device */
1473 group = make_kgid(current_user_ns(), arg);
1474 if (!gid_valid(group)) {
1475 ret = -EINVAL;
1476 break;
1477 }
1478 tun->group = group;
1479 tun_debug(KERN_INFO, tun, "group set to %u\n",
1480 from_kgid(&init_user_ns, tun->group));
1481 break;
1482
1483 case TUNSETLINK:
1484 /* Only allow setting the type when the interface is down */
1485 if (tun->dev->flags & IFF_UP) {
1486 tun_debug(KERN_INFO, tun,
1487 "Linktype set failed because interface is up\n");
1488 ret = -EBUSY;
1489 } else {
1490 tun->dev->type = (int) arg;
1491 tun_debug(KERN_INFO, tun, "linktype set to %d\n",
1492 tun->dev->type);
1493 ret = 0;
1494 }
1495 break;
1496
1497 #ifdef TUN_DEBUG
1498 case TUNSETDEBUG:
1499 tun->debug = arg;
1500 break;
1501 #endif
1502 case TUNSETOFFLOAD:
1503 ret = set_offload(tun, arg);
1504 break;
1505
1506 case TUNSETTXFILTER:
1507 /* Can be set only for TAPs */
1508 ret = -EINVAL;
1509 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1510 break;
1511 ret = update_filter(&tun->txflt, (void __user *)arg);
1512 break;
1513
1514 case SIOCGIFHWADDR:
1515 /* Get hw address */
1516 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
1517 ifr.ifr_hwaddr.sa_family = tun->dev->type;
1518 if (copy_to_user(argp, &ifr, ifreq_len))
1519 ret = -EFAULT;
1520 break;
1521
1522 case SIOCSIFHWADDR:
1523 /* Set hw address */
1524 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
1525 ifr.ifr_hwaddr.sa_data);
1526
1527 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
1528 break;
1529
1530 case TUNGETSNDBUF:
1531 sndbuf = tfile->socket.sk->sk_sndbuf;
1532 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
1533 ret = -EFAULT;
1534 break;
1535
1536 case TUNSETSNDBUF:
1537 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
1538 ret = -EFAULT;
1539 break;
1540 }
1541
1542 tun->sndbuf = tfile->socket.sk->sk_sndbuf = sndbuf;
1543 break;
1544
1545 case TUNGETVNETHDRSZ:
1546 vnet_hdr_sz = tun->vnet_hdr_sz;
1547 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
1548 ret = -EFAULT;
1549 break;
1550
1551 case TUNSETVNETHDRSZ:
1552 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
1553 ret = -EFAULT;
1554 break;
1555 }
1556 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
1557 ret = -EINVAL;
1558 break;
1559 }
1560
1561 tun->vnet_hdr_sz = vnet_hdr_sz;
1562 break;
1563
1564 case TUNATTACHFILTER:
1565 /* Can be set only for TAPs */
1566 ret = -EINVAL;
1567 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1568 break;
1569 ret = -EFAULT;
1570 if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
1571 break;
1572
1573 ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
1574 if (!ret)
1575 tun->filter_attached = true;
1576 break;
1577
1578 case TUNDETACHFILTER:
1579 /* Can be set only for TAPs */
1580 ret = -EINVAL;
1581 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1582 break;
1583 ret = sk_detach_filter(tfile->socket.sk);
1584 if (!ret)
1585 tun->filter_attached = false;
1586 break;
1587
1588 default:
1589 ret = -EINVAL;
1590 break;
1591 }
1592
1593 unlock:
1594 rtnl_unlock();
1595 if (tun)
1596 tun_put(tun);
1597 return ret;
1598 }
1599
1600 static long tun_chr_ioctl(struct file *file,
1601 unsigned int cmd, unsigned long arg)
1602 {
1603 return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
1604 }
1605
1606 #ifdef CONFIG_COMPAT
1607 static long tun_chr_compat_ioctl(struct file *file,
1608 unsigned int cmd, unsigned long arg)
1609 {
1610 switch (cmd) {
1611 case TUNSETIFF:
1612 case TUNGETIFF:
1613 case TUNSETTXFILTER:
1614 case TUNGETSNDBUF:
1615 case TUNSETSNDBUF:
1616 case SIOCGIFHWADDR:
1617 case SIOCSIFHWADDR:
1618 arg = (unsigned long)compat_ptr(arg);
1619 break;
1620 default:
1621 arg = (compat_ulong_t)arg;
1622 break;
1623 }
1624
1625 /*
1626 * compat_ifreq is shorter than ifreq, so we must not access beyond
1627 * the end of that structure. All fields that are used in this
1628 * driver are compatible though, we don't need to convert the
1629 * contents.
1630 */
1631 return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
1632 }
1633 #endif /* CONFIG_COMPAT */
1634
1635 static int tun_chr_fasync(int fd, struct file *file, int on)
1636 {
1637 struct tun_file *tfile = file->private_data;
1638 int ret;
1639
1640 if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
1641 goto out;
1642
1643 if (on) {
1644 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
1645 if (ret)
1646 goto out;
1647 tfile->flags |= TUN_FASYNC;
1648 } else
1649 tfile->flags &= ~TUN_FASYNC;
1650 ret = 0;
1651 out:
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 = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL,
1662 &tun_proto);
1663 if (!tfile)
1664 return -ENOMEM;
1665 atomic_set(&tfile->count, 0);
1666 tfile->tun = NULL;
1667 tfile->net = get_net(current->nsproxy->net_ns);
1668 tfile->flags = 0;
1669
1670 rcu_assign_pointer(tfile->socket.wq, &tfile->wq);
1671 init_waitqueue_head(&tfile->wq.wait);
1672
1673 tfile->socket.file = file;
1674 tfile->socket.ops = &tun_socket_ops;
1675
1676 sock_init_data(&tfile->socket, &tfile->sk);
1677 sk_change_net(&tfile->sk, tfile->net);
1678
1679 tfile->sk.sk_write_space = tun_sock_write_space;
1680 tfile->sk.sk_sndbuf = INT_MAX;
1681
1682 file->private_data = tfile;
1683 set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags);
1684
1685 return 0;
1686 }
1687
1688 static int tun_chr_close(struct inode *inode, struct file *file)
1689 {
1690 struct tun_file *tfile = file->private_data;
1691 struct tun_struct *tun;
1692 struct net *net = tfile->net;
1693
1694 tun = __tun_get(tfile);
1695 if (tun) {
1696 struct net_device *dev = tun->dev;
1697
1698 tun_debug(KERN_INFO, tun, "tun_chr_close\n");
1699
1700 __tun_detach(tun);
1701
1702 /* If desirable, unregister the netdevice. */
1703 if (!(tun->flags & TUN_PERSIST)) {
1704 rtnl_lock();
1705 if (dev->reg_state == NETREG_REGISTERED)
1706 unregister_netdevice(dev);
1707 rtnl_unlock();
1708 }
1709
1710 /* drop the reference that netdevice holds */
1711 sock_put(&tfile->sk);
1712 }
1713
1714 /* drop the reference that file holds */
1715 BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED,
1716 &tfile->socket.flags));
1717 sk_release_kernel(&tfile->sk);
1718 put_net(net);
1719
1720 return 0;
1721 }
1722
1723 static const struct file_operations tun_fops = {
1724 .owner = THIS_MODULE,
1725 .llseek = no_llseek,
1726 .read = do_sync_read,
1727 .aio_read = tun_chr_aio_read,
1728 .write = do_sync_write,
1729 .aio_write = tun_chr_aio_write,
1730 .poll = tun_chr_poll,
1731 .unlocked_ioctl = tun_chr_ioctl,
1732 #ifdef CONFIG_COMPAT
1733 .compat_ioctl = tun_chr_compat_ioctl,
1734 #endif
1735 .open = tun_chr_open,
1736 .release = tun_chr_close,
1737 .fasync = tun_chr_fasync
1738 };
1739
1740 static struct miscdevice tun_miscdev = {
1741 .minor = TUN_MINOR,
1742 .name = "tun",
1743 .nodename = "net/tun",
1744 .fops = &tun_fops,
1745 };
1746
1747 /* ethtool interface */
1748
1749 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
1750 {
1751 cmd->supported = 0;
1752 cmd->advertising = 0;
1753 ethtool_cmd_speed_set(cmd, SPEED_10);
1754 cmd->duplex = DUPLEX_FULL;
1755 cmd->port = PORT_TP;
1756 cmd->phy_address = 0;
1757 cmd->transceiver = XCVR_INTERNAL;
1758 cmd->autoneg = AUTONEG_DISABLE;
1759 cmd->maxtxpkt = 0;
1760 cmd->maxrxpkt = 0;
1761 return 0;
1762 }
1763
1764 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
1765 {
1766 struct tun_struct *tun = netdev_priv(dev);
1767
1768 strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
1769 strlcpy(info->version, DRV_VERSION, sizeof(info->version));
1770
1771 switch (tun->flags & TUN_TYPE_MASK) {
1772 case TUN_TUN_DEV:
1773 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
1774 break;
1775 case TUN_TAP_DEV:
1776 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
1777 break;
1778 }
1779 }
1780
1781 static u32 tun_get_msglevel(struct net_device *dev)
1782 {
1783 #ifdef TUN_DEBUG
1784 struct tun_struct *tun = netdev_priv(dev);
1785 return tun->debug;
1786 #else
1787 return -EOPNOTSUPP;
1788 #endif
1789 }
1790
1791 static void tun_set_msglevel(struct net_device *dev, u32 value)
1792 {
1793 #ifdef TUN_DEBUG
1794 struct tun_struct *tun = netdev_priv(dev);
1795 tun->debug = value;
1796 #endif
1797 }
1798
1799 static const struct ethtool_ops tun_ethtool_ops = {
1800 .get_settings = tun_get_settings,
1801 .get_drvinfo = tun_get_drvinfo,
1802 .get_msglevel = tun_get_msglevel,
1803 .set_msglevel = tun_set_msglevel,
1804 .get_link = ethtool_op_get_link,
1805 };
1806
1807
1808 static int __init tun_init(void)
1809 {
1810 int ret = 0;
1811
1812 pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
1813 pr_info("%s\n", DRV_COPYRIGHT);
1814
1815 ret = rtnl_link_register(&tun_link_ops);
1816 if (ret) {
1817 pr_err("Can't register link_ops\n");
1818 goto err_linkops;
1819 }
1820
1821 ret = misc_register(&tun_miscdev);
1822 if (ret) {
1823 pr_err("Can't register misc device %d\n", TUN_MINOR);
1824 goto err_misc;
1825 }
1826 return 0;
1827 err_misc:
1828 rtnl_link_unregister(&tun_link_ops);
1829 err_linkops:
1830 return ret;
1831 }
1832
1833 static void tun_cleanup(void)
1834 {
1835 misc_deregister(&tun_miscdev);
1836 rtnl_link_unregister(&tun_link_ops);
1837 }
1838
1839 /* Get an underlying socket object from tun file. Returns error unless file is
1840 * attached to a device. The returned object works like a packet socket, it
1841 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
1842 * holding a reference to the file for as long as the socket is in use. */
1843 struct socket *tun_get_socket(struct file *file)
1844 {
1845 struct tun_struct *tun;
1846 struct tun_file *tfile = file->private_data;
1847 if (file->f_op != &tun_fops)
1848 return ERR_PTR(-EINVAL);
1849 tun = tun_get(file);
1850 if (!tun)
1851 return ERR_PTR(-EBADFD);
1852 tun_put(tun);
1853 return &tfile->socket;
1854 }
1855 EXPORT_SYMBOL_GPL(tun_get_socket);
1856
1857 module_init(tun_init);
1858 module_exit(tun_cleanup);
1859 MODULE_DESCRIPTION(DRV_DESCRIPTION);
1860 MODULE_AUTHOR(DRV_COPYRIGHT);
1861 MODULE_LICENSE("GPL");
1862 MODULE_ALIAS_MISCDEV(TUN_MINOR);
1863 MODULE_ALIAS("devname:net/tun");
Linux kernel - Deliverables
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