Bootlin logo

Elixir Cross Referencer

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
/*
 *  TUN - Universal TUN/TAP device driver.
 *  Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 *  GNU General Public License for more details.
 *
 *  $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
 */

/*
 *  Changes:
 *
 *  Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
 *    Add TUNSETLINK ioctl to set the link encapsulation
 *
 *  Mark Smith <markzzzsmith@yahoo.com.au>
 *   Use random_ether_addr() for tap MAC address.
 *
 *  Harald Roelle <harald.roelle@ifi.lmu.de>  2004/04/20
 *    Fixes in packet dropping, queue length setting and queue wakeup.
 *    Increased default tx queue length.
 *    Added ethtool API.
 *    Minor cleanups
 *
 *  Daniel Podlejski <underley@underley.eu.org>
 *    Modifications for 2.3.99-pre5 kernel.
 */

#define DRV_NAME	"tun"
#define DRV_VERSION	"1.6"
#define DRV_DESCRIPTION	"Universal TUN/TAP device driver"
#define DRV_COPYRIGHT	"(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/slab.h>
#include <linux/poll.h>
#include <linux/fcntl.h>
#include <linux/init.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/miscdevice.h>
#include <linux/ethtool.h>
#include <linux/rtnetlink.h>
#include <linux/if.h>
#include <linux/if_arp.h>
#include <linux/if_ether.h>
#include <linux/if_tun.h>
#include <linux/crc32.h>

#include <asm/system.h>
#include <asm/uaccess.h>

#ifdef TUN_DEBUG
static int debug;
#endif

/* Network device part of the driver */

static LIST_HEAD(tun_dev_list);
static const struct ethtool_ops tun_ethtool_ops;

/* Net device open. */
static int tun_net_open(struct net_device *dev)
{
	netif_start_queue(dev);
	return 0;
}

/* Net device close. */
static int tun_net_close(struct net_device *dev)
{
	netif_stop_queue(dev);
	return 0;
}

/* Net device start xmit */
static int tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct tun_struct *tun = netdev_priv(dev);

	DBG(KERN_INFO "%s: tun_net_xmit %d\n", tun->dev->name, skb->len);

	/* Drop packet if interface is not attached */
	if (!tun->attached)
		goto drop;

	/* Packet dropping */
	if (skb_queue_len(&tun->readq) >= dev->tx_queue_len) {
		if (!(tun->flags & TUN_ONE_QUEUE)) {
			/* Normal queueing mode. */
			/* Packet scheduler handles dropping of further packets. */
			netif_stop_queue(dev);

			/* We won't see all dropped packets individually, so overrun
			 * error is more appropriate. */
			tun->stats.tx_fifo_errors++;
		} else {
			/* Single queue mode.
			 * Driver handles dropping of all packets itself. */
			goto drop;
		}
	}

	/* Queue packet */
	skb_queue_tail(&tun->readq, skb);
	dev->trans_start = jiffies;

	/* Notify and wake up reader process */
	if (tun->flags & TUN_FASYNC)
		kill_fasync(&tun->fasync, SIGIO, POLL_IN);
	wake_up_interruptible(&tun->read_wait);
	return 0;

drop:
	tun->stats.tx_dropped++;
	kfree_skb(skb);
	return 0;
}

/** Add the specified Ethernet address to this multicast filter. */
static void
add_multi(u32* filter, const u8* addr)
{
	int bit_nr = ether_crc(ETH_ALEN, addr) >> 26;
	filter[bit_nr >> 5] |= 1 << (bit_nr & 31);
}

/** Remove the specified Ethernet addres from this multicast filter. */
static void
del_multi(u32* filter, const u8* addr)
{
	int bit_nr = ether_crc(ETH_ALEN, addr) >> 26;
	filter[bit_nr >> 5] &= ~(1 << (bit_nr & 31));
}

/** Update the list of multicast groups to which the network device belongs.
 * This list is used to filter packets being sent from the character device to
 * the network device. */
static void
tun_net_mclist(struct net_device *dev)
{
	struct tun_struct *tun = netdev_priv(dev);
	const struct dev_mc_list *mclist;
	int i;
	DBG(KERN_DEBUG "%s: tun_net_mclist: mc_count %d\n",
			dev->name, dev->mc_count);
	memset(tun->chr_filter, 0, sizeof tun->chr_filter);
	for (i = 0, mclist = dev->mc_list; i < dev->mc_count && mclist != NULL;
			i++, mclist = mclist->next) {
		add_multi(tun->net_filter, mclist->dmi_addr);
		DBG(KERN_DEBUG "%s: tun_net_mclist: %x:%x:%x:%x:%x:%x\n",
				dev->name,
				mclist->dmi_addr[0], mclist->dmi_addr[1], mclist->dmi_addr[2],
				mclist->dmi_addr[3], mclist->dmi_addr[4], mclist->dmi_addr[5]);
	}
}

static struct net_device_stats *tun_net_stats(struct net_device *dev)
{
	struct tun_struct *tun = netdev_priv(dev);
	return &tun->stats;
}

/* Initialize net device. */
static void tun_net_init(struct net_device *dev)
{
	struct tun_struct *tun = netdev_priv(dev);

	switch (tun->flags & TUN_TYPE_MASK) {
	case TUN_TUN_DEV:
		/* Point-to-Point TUN Device */
		dev->hard_header_len = 0;
		dev->addr_len = 0;
		dev->mtu = 1500;

		/* Zero header length */
		dev->type = ARPHRD_NONE;
		dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
		dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
		break;

	case TUN_TAP_DEV:
		/* Ethernet TAP Device */
		dev->set_multicast_list = tun_net_mclist;

		ether_setup(dev);
		random_ether_addr(dev->dev_addr);
		dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
		break;
	}
}

/* Character device part */

/* Poll */
static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
{
	struct tun_struct *tun = file->private_data;
	unsigned int mask = POLLOUT | POLLWRNORM;

	if (!tun)
		return -EBADFD;

	DBG(KERN_INFO "%s: tun_chr_poll\n", tun->dev->name);

	poll_wait(file, &tun->read_wait, wait);

	if (!skb_queue_empty(&tun->readq))
		mask |= POLLIN | POLLRDNORM;

	return mask;
}

/* Get packet from user space buffer */
static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct iovec *iv, size_t count)
{
	struct tun_pi pi = { 0, __constant_htons(ETH_P_IP) };
	struct sk_buff *skb;
	size_t len = count, align = 0;

	if (!(tun->flags & TUN_NO_PI)) {
		if ((len -= sizeof(pi)) > count)
			return -EINVAL;

		if(memcpy_fromiovec((void *)&pi, iv, sizeof(pi)))
			return -EFAULT;
	}

	if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV)
		align = NET_IP_ALIGN;

	if (!(skb = alloc_skb(len + align, GFP_KERNEL))) {
		tun->stats.rx_dropped++;
		return -ENOMEM;
	}

	if (align)
		skb_reserve(skb, align);
	if (memcpy_fromiovec(skb_put(skb, len), iv, len)) {
		tun->stats.rx_dropped++;
		kfree_skb(skb);
		return -EFAULT;
	}

	skb->dev = tun->dev;
	switch (tun->flags & TUN_TYPE_MASK) {
	case TUN_TUN_DEV:
		skb->mac.raw = skb->data;
		skb->protocol = pi.proto;
		break;
	case TUN_TAP_DEV:
		skb->protocol = eth_type_trans(skb, tun->dev);
		break;
	};

	if (tun->flags & TUN_NOCHECKSUM)
		skb->ip_summed = CHECKSUM_UNNECESSARY;

	netif_rx_ni(skb);
	tun->dev->last_rx = jiffies;

	tun->stats.rx_packets++;
	tun->stats.rx_bytes += len;

	return count;
}

static inline size_t iov_total(const struct iovec *iv, unsigned long count)
{
	unsigned long i;
	size_t len;

	for (i = 0, len = 0; i < count; i++)
		len += iv[i].iov_len;

	return len;
}

static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
			      unsigned long count, loff_t pos)
{
	struct tun_struct *tun = iocb->ki_filp->private_data;

	if (!tun)
		return -EBADFD;

	DBG(KERN_INFO "%s: tun_chr_write %ld\n", tun->dev->name, count);

	return tun_get_user(tun, (struct iovec *) iv, iov_total(iv, count));
}

/* Put packet to the user space buffer */
static __inline__ ssize_t tun_put_user(struct tun_struct *tun,
				       struct sk_buff *skb,
				       struct iovec *iv, int len)
{
	struct tun_pi pi = { 0, skb->protocol };
	ssize_t total = 0;

	if (!(tun->flags & TUN_NO_PI)) {
		if ((len -= sizeof(pi)) < 0)
			return -EINVAL;

		if (len < skb->len) {
			/* Packet will be striped */
			pi.flags |= TUN_PKT_STRIP;
		}

		if (memcpy_toiovec(iv, (void *) &pi, sizeof(pi)))
			return -EFAULT;
		total += sizeof(pi);
	}

	len = min_t(int, skb->len, len);

	skb_copy_datagram_iovec(skb, 0, iv, len);
	total += len;

	tun->stats.tx_packets++;
	tun->stats.tx_bytes += len;

	return total;
}

static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
			    unsigned long count, loff_t pos)
{
	struct file *file = iocb->ki_filp;
	struct tun_struct *tun = file->private_data;
	DECLARE_WAITQUEUE(wait, current);
	struct sk_buff *skb;
	ssize_t len, ret = 0;

	if (!tun)
		return -EBADFD;

	DBG(KERN_INFO "%s: tun_chr_read\n", tun->dev->name);

	len = iov_total(iv, count);
	if (len < 0)
		return -EINVAL;

	add_wait_queue(&tun->read_wait, &wait);
	while (len) {
		const u8 ones[ ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
		u8 addr[ ETH_ALEN];
		int bit_nr;

		current->state = TASK_INTERRUPTIBLE;

		/* Read frames from the queue */
		if (!(skb=skb_dequeue(&tun->readq))) {
			if (file->f_flags & O_NONBLOCK) {
				ret = -EAGAIN;
				break;
			}
			if (signal_pending(current)) {
				ret = -ERESTARTSYS;
				break;
			}

			/* Nothing to read, let's sleep */
			schedule();
			continue;
		}
		netif_wake_queue(tun->dev);

		/** Decide whether to accept this packet. This code is designed to
		 * behave identically to an Ethernet interface. Accept the packet if
		 * - we are promiscuous.
		 * - the packet is addressed to us.
		 * - the packet is broadcast.
		 * - the packet is multicast and
		 *   - we are multicast promiscous.
		 *   - we belong to the multicast group.
		 */
		memcpy(addr, skb->data,
		       min_t(size_t, sizeof addr, skb->len));
		bit_nr = ether_crc(sizeof addr, addr) >> 26;
		if ((tun->if_flags & IFF_PROMISC) ||
				memcmp(addr, tun->dev_addr, sizeof addr) == 0 ||
				memcmp(addr, ones, sizeof addr) == 0 ||
				(((addr[0] == 1 && addr[1] == 0 && addr[2] == 0x5e) ||
				  (addr[0] == 0x33 && addr[1] == 0x33)) &&
				 ((tun->if_flags & IFF_ALLMULTI) ||
				  (tun->chr_filter[bit_nr >> 5] & (1 << (bit_nr & 31)))))) {
			DBG(KERN_DEBUG "%s: tun_chr_readv: accepted: %x:%x:%x:%x:%x:%x\n",
					tun->dev->name, addr[0], addr[1], addr[2],
					addr[3], addr[4], addr[5]);
			ret = tun_put_user(tun, skb, (struct iovec *) iv, len);
			kfree_skb(skb);
			break;
		} else {
			DBG(KERN_DEBUG "%s: tun_chr_readv: rejected: %x:%x:%x:%x:%x:%x\n",
					tun->dev->name, addr[0], addr[1], addr[2],
					addr[3], addr[4], addr[5]);
			kfree_skb(skb);
			continue;
		}
	}

	current->state = TASK_RUNNING;
	remove_wait_queue(&tun->read_wait, &wait);

	return ret;
}

static void tun_setup(struct net_device *dev)
{
	struct tun_struct *tun = netdev_priv(dev);

	skb_queue_head_init(&tun->readq);
	init_waitqueue_head(&tun->read_wait);

	tun->owner = -1;

	SET_MODULE_OWNER(dev);
	dev->open = tun_net_open;
	dev->hard_start_xmit = tun_net_xmit;
	dev->stop = tun_net_close;
	dev->get_stats = tun_net_stats;
	dev->ethtool_ops = &tun_ethtool_ops;
	dev->destructor = free_netdev;
}

static struct tun_struct *tun_get_by_name(const char *name)
{
	struct tun_struct *tun;

	ASSERT_RTNL();
	list_for_each_entry(tun, &tun_dev_list, list) {
		if (!strncmp(tun->dev->name, name, IFNAMSIZ))
		    return tun;
	}

	return NULL;
}

static int tun_set_iff(struct file *file, struct ifreq *ifr)
{
	struct tun_struct *tun;
	struct net_device *dev;
	int err;

	tun = tun_get_by_name(ifr->ifr_name);
	if (tun) {
		if (tun->attached)
			return -EBUSY;

		/* Check permissions */
		if (tun->owner != -1 &&
		    current->euid != tun->owner && !capable(CAP_NET_ADMIN))
			return -EPERM;
	}
	else if (__dev_get_by_name(ifr->ifr_name))
		return -EINVAL;
	else {
		char *name;
		unsigned long flags = 0;

		err = -EINVAL;

		if (!capable(CAP_NET_ADMIN))
			return -EPERM;

		/* Set dev type */
		if (ifr->ifr_flags & IFF_TUN) {
			/* TUN device */
			flags |= TUN_TUN_DEV;
			name = "tun%d";
		} else if (ifr->ifr_flags & IFF_TAP) {
			/* TAP device */
			flags |= TUN_TAP_DEV;
			name = "tap%d";
		} else
			goto failed;

		if (*ifr->ifr_name)
			name = ifr->ifr_name;

		dev = alloc_netdev(sizeof(struct tun_struct), name,
				   tun_setup);
		if (!dev)
			return -ENOMEM;

		tun = netdev_priv(dev);
		tun->dev = dev;
		tun->flags = flags;
		/* Be promiscuous by default to maintain previous behaviour. */
		tun->if_flags = IFF_PROMISC;
		/* Generate random Ethernet address. */
		*(u16 *)tun->dev_addr = htons(0x00FF);
		get_random_bytes(tun->dev_addr + sizeof(u16), 4);
		memset(tun->chr_filter, 0, sizeof tun->chr_filter);

		tun_net_init(dev);

		if (strchr(dev->name, '%')) {
			err = dev_alloc_name(dev, dev->name);
			if (err < 0)
				goto err_free_dev;
		}

		err = register_netdevice(tun->dev);
		if (err < 0)
			goto err_free_dev;

		list_add(&tun->list, &tun_dev_list);
	}

	DBG(KERN_INFO "%s: tun_set_iff\n", tun->dev->name);

	if (ifr->ifr_flags & IFF_NO_PI)
		tun->flags |= TUN_NO_PI;

	if (ifr->ifr_flags & IFF_ONE_QUEUE)
		tun->flags |= TUN_ONE_QUEUE;

	file->private_data = tun;
	tun->attached = 1;

	strcpy(ifr->ifr_name, tun->dev->name);
	return 0;

 err_free_dev:
	free_netdev(dev);
 failed:
	return err;
}

static int tun_chr_ioctl(struct inode *inode, struct file *file,
			 unsigned int cmd, unsigned long arg)
{
	struct tun_struct *tun = file->private_data;
	void __user* argp = (void __user*)arg;
	struct ifreq ifr;

	if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
		if (copy_from_user(&ifr, argp, sizeof ifr))
			return -EFAULT;

	if (cmd == TUNSETIFF && !tun) {
		int err;

		ifr.ifr_name[IFNAMSIZ-1] = '\0';

		rtnl_lock();
		err = tun_set_iff(file, &ifr);
		rtnl_unlock();

		if (err)
			return err;

		if (copy_to_user(argp, &ifr, sizeof(ifr)))
			return -EFAULT;
		return 0;
	}

	if (!tun)
		return -EBADFD;

	DBG(KERN_INFO "%s: tun_chr_ioctl cmd %d\n", tun->dev->name, cmd);

	switch (cmd) {
	case TUNSETNOCSUM:
		/* Disable/Enable checksum */
		if (arg)
			tun->flags |= TUN_NOCHECKSUM;
		else
			tun->flags &= ~TUN_NOCHECKSUM;

		DBG(KERN_INFO "%s: checksum %s\n",
		    tun->dev->name, arg ? "disabled" : "enabled");
		break;

	case TUNSETPERSIST:
		/* Disable/Enable persist mode */
		if (arg)
			tun->flags |= TUN_PERSIST;
		else
			tun->flags &= ~TUN_PERSIST;

		DBG(KERN_INFO "%s: persist %s\n",
		    tun->dev->name, arg ? "disabled" : "enabled");
		break;

	case TUNSETOWNER:
		/* Set owner of the device */
		tun->owner = (uid_t) arg;

		DBG(KERN_INFO "%s: owner set to %d\n", tun->dev->name, tun->owner);
		break;

	case TUNSETLINK:
		/* Only allow setting the type when the interface is down */
		if (tun->dev->flags & IFF_UP) {
			DBG(KERN_INFO "%s: Linktype set failed because interface is up\n",
				tun->dev->name);
			return -EBUSY;
		} else {
			tun->dev->type = (int) arg;
			DBG(KERN_INFO "%s: linktype set to %d\n", tun->dev->name, tun->dev->type);
		}
		break;

#ifdef TUN_DEBUG
	case TUNSETDEBUG:
		tun->debug = arg;
		break;
#endif

	case SIOCGIFFLAGS:
		ifr.ifr_flags = tun->if_flags;
		if (copy_to_user( argp, &ifr, sizeof ifr))
			return -EFAULT;
		return 0;

	case SIOCSIFFLAGS:
		/** Set the character device's interface flags. Currently only
		 * IFF_PROMISC and IFF_ALLMULTI are used. */
		tun->if_flags = ifr.ifr_flags;
		DBG(KERN_INFO "%s: interface flags 0x%lx\n",
				tun->dev->name, tun->if_flags);
		return 0;

	case SIOCGIFHWADDR:
		memcpy(ifr.ifr_hwaddr.sa_data, tun->dev_addr,
				min(sizeof ifr.ifr_hwaddr.sa_data, sizeof tun->dev_addr));
		if (copy_to_user( argp, &ifr, sizeof ifr))
			return -EFAULT;
		return 0;

	case SIOCSIFHWADDR:
		/** Set the character device's hardware address. This is used when
		 * filtering packets being sent from the network device to the character
		 * device. */
		memcpy(tun->dev_addr, ifr.ifr_hwaddr.sa_data,
				min(sizeof ifr.ifr_hwaddr.sa_data, sizeof tun->dev_addr));
		DBG(KERN_DEBUG "%s: set hardware address: %x:%x:%x:%x:%x:%x\n",
				tun->dev->name,
				tun->dev_addr[0], tun->dev_addr[1], tun->dev_addr[2],
				tun->dev_addr[3], tun->dev_addr[4], tun->dev_addr[5]);
		return 0;

	case SIOCADDMULTI:
		/** Add the specified group to the character device's multicast filter
		 * list. */
		add_multi(tun->chr_filter, ifr.ifr_hwaddr.sa_data);
		DBG(KERN_DEBUG "%s: add multi: %x:%x:%x:%x:%x:%x\n",
				tun->dev->name,
				(u8)ifr.ifr_hwaddr.sa_data[0], (u8)ifr.ifr_hwaddr.sa_data[1],
				(u8)ifr.ifr_hwaddr.sa_data[2], (u8)ifr.ifr_hwaddr.sa_data[3],
				(u8)ifr.ifr_hwaddr.sa_data[4], (u8)ifr.ifr_hwaddr.sa_data[5]);
		return 0;

	case SIOCDELMULTI:
		/** Remove the specified group from the character device's multicast
		 * filter list. */
		del_multi(tun->chr_filter, ifr.ifr_hwaddr.sa_data);
		DBG(KERN_DEBUG "%s: del multi: %x:%x:%x:%x:%x:%x\n",
				tun->dev->name,
				(u8)ifr.ifr_hwaddr.sa_data[0], (u8)ifr.ifr_hwaddr.sa_data[1],
				(u8)ifr.ifr_hwaddr.sa_data[2], (u8)ifr.ifr_hwaddr.sa_data[3],
				(u8)ifr.ifr_hwaddr.sa_data[4], (u8)ifr.ifr_hwaddr.sa_data[5]);
		return 0;

	default:
		return -EINVAL;
	};

	return 0;
}

static int tun_chr_fasync(int fd, struct file *file, int on)
{
	struct tun_struct *tun = file->private_data;
	int ret;

	if (!tun)
		return -EBADFD;

	DBG(KERN_INFO "%s: tun_chr_fasync %d\n", tun->dev->name, on);

	if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
		return ret;

	if (on) {
		ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
		if (ret)
			return ret;
		tun->flags |= TUN_FASYNC;
	} else
		tun->flags &= ~TUN_FASYNC;

	return 0;
}

static int tun_chr_open(struct inode *inode, struct file * file)
{
	DBG1(KERN_INFO "tunX: tun_chr_open\n");
	file->private_data = NULL;
	return 0;
}

static int tun_chr_close(struct inode *inode, struct file *file)
{
	struct tun_struct *tun = file->private_data;

	if (!tun)
		return 0;

	DBG(KERN_INFO "%s: tun_chr_close\n", tun->dev->name);

	tun_chr_fasync(-1, file, 0);

	rtnl_lock();

	/* Detach from net device */
	file->private_data = NULL;
	tun->attached = 0;

	/* Drop read queue */
	skb_queue_purge(&tun->readq);

	if (!(tun->flags & TUN_PERSIST)) {
		list_del(&tun->list);
		unregister_netdevice(tun->dev);
	}

	rtnl_unlock();

	return 0;
}

static struct file_operations tun_fops = {
	.owner	= THIS_MODULE,
	.llseek = no_llseek,
	.read  = do_sync_read,
	.aio_read  = tun_chr_aio_read,
	.write = do_sync_write,
	.aio_write = tun_chr_aio_write,
	.poll	= tun_chr_poll,
	.ioctl	= tun_chr_ioctl,
	.open	= tun_chr_open,
	.release = tun_chr_close,
	.fasync = tun_chr_fasync
};

static struct miscdevice tun_miscdev = {
	.minor = TUN_MINOR,
	.name = "tun",
	.fops = &tun_fops,
};

/* ethtool interface */

static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
{
	cmd->supported		= 0;
	cmd->advertising	= 0;
	cmd->speed		= SPEED_10;
	cmd->duplex		= DUPLEX_FULL;
	cmd->port		= PORT_TP;
	cmd->phy_address	= 0;
	cmd->transceiver	= XCVR_INTERNAL;
	cmd->autoneg		= AUTONEG_DISABLE;
	cmd->maxtxpkt		= 0;
	cmd->maxrxpkt		= 0;
	return 0;
}

static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
{
	struct tun_struct *tun = netdev_priv(dev);

	strcpy(info->driver, DRV_NAME);
	strcpy(info->version, DRV_VERSION);
	strcpy(info->fw_version, "N/A");

	switch (tun->flags & TUN_TYPE_MASK) {
	case TUN_TUN_DEV:
		strcpy(info->bus_info, "tun");
		break;
	case TUN_TAP_DEV:
		strcpy(info->bus_info, "tap");
		break;
	}
}

static u32 tun_get_msglevel(struct net_device *dev)
{
#ifdef TUN_DEBUG
	struct tun_struct *tun = netdev_priv(dev);
	return tun->debug;
#else
	return -EOPNOTSUPP;
#endif
}

static void tun_set_msglevel(struct net_device *dev, u32 value)
{
#ifdef TUN_DEBUG
	struct tun_struct *tun = netdev_priv(dev);
	tun->debug = value;
#endif
}

static u32 tun_get_link(struct net_device *dev)
{
	struct tun_struct *tun = netdev_priv(dev);
	return tun->attached;
}

static u32 tun_get_rx_csum(struct net_device *dev)
{
	struct tun_struct *tun = netdev_priv(dev);
	return (tun->flags & TUN_NOCHECKSUM) == 0;
}

static int tun_set_rx_csum(struct net_device *dev, u32 data)
{
	struct tun_struct *tun = netdev_priv(dev);
	if (data)
		tun->flags &= ~TUN_NOCHECKSUM;
	else
		tun->flags |= TUN_NOCHECKSUM;
	return 0;
}

static const struct ethtool_ops tun_ethtool_ops = {
	.get_settings	= tun_get_settings,
	.get_drvinfo	= tun_get_drvinfo,
	.get_msglevel	= tun_get_msglevel,
	.set_msglevel	= tun_set_msglevel,
	.get_link	= tun_get_link,
	.get_rx_csum	= tun_get_rx_csum,
	.set_rx_csum	= tun_set_rx_csum
};

static int __init tun_init(void)
{
	int ret = 0;

	printk(KERN_INFO "tun: %s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
	printk(KERN_INFO "tun: %s\n", DRV_COPYRIGHT);

	ret = misc_register(&tun_miscdev);
	if (ret)
		printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR);
	return ret;
}

static void tun_cleanup(void)
{
	struct tun_struct *tun, *nxt;

	misc_deregister(&tun_miscdev);

	rtnl_lock();
	list_for_each_entry_safe(tun, nxt, &tun_dev_list, list) {
		DBG(KERN_INFO "%s cleaned up\n", tun->dev->name);
		unregister_netdevice(tun->dev);
	}
	rtnl_unlock();

}

module_init(tun_init);
module_exit(tun_cleanup);
MODULE_DESCRIPTION(DRV_DESCRIPTION);
MODULE_AUTHOR(DRV_COPYRIGHT);
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(TUN_MINOR);