xref: /linux/drivers/net/tun.c (revision f3d9478b2ce468c3115b02ecae7e975990697f15)
1 /*
2  *  TUN - Universal TUN/TAP device driver.
3  *  Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com>
4  *
5  *  This program is free software; you can redistribute it and/or modify
6  *  it under the terms of the GNU General Public License as published by
7  *  the Free Software Foundation; either version 2 of the License, or
8  *  (at your option) any later version.
9  *
10  *  This program is distributed in the hope that it will be useful,
11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13  *  GNU General Public License for more details.
14  *
15  *  $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
16  */
17 
18 /*
19  *  Changes:
20  *
21  *  Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
22  *    Add TUNSETLINK ioctl to set the link encapsulation
23  *
24  *  Mark Smith <markzzzsmith@yahoo.com.au>
25  *   Use random_ether_addr() for tap MAC address.
26  *
27  *  Harald Roelle <harald.roelle@ifi.lmu.de>  2004/04/20
28  *    Fixes in packet dropping, queue length setting and queue wakeup.
29  *    Increased default tx queue length.
30  *    Added ethtool API.
31  *    Minor cleanups
32  *
33  *  Daniel Podlejski <underley@underley.eu.org>
34  *    Modifications for 2.3.99-pre5 kernel.
35  */
36 
37 #define DRV_NAME	"tun"
38 #define DRV_VERSION	"1.6"
39 #define DRV_DESCRIPTION	"Universal TUN/TAP device driver"
40 #define DRV_COPYRIGHT	"(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
41 
42 #include <linux/config.h>
43 #include <linux/module.h>
44 #include <linux/errno.h>
45 #include <linux/kernel.h>
46 #include <linux/major.h>
47 #include <linux/slab.h>
48 #include <linux/poll.h>
49 #include <linux/fcntl.h>
50 #include <linux/init.h>
51 #include <linux/skbuff.h>
52 #include <linux/netdevice.h>
53 #include <linux/etherdevice.h>
54 #include <linux/miscdevice.h>
55 #include <linux/ethtool.h>
56 #include <linux/rtnetlink.h>
57 #include <linux/if.h>
58 #include <linux/if_arp.h>
59 #include <linux/if_ether.h>
60 #include <linux/if_tun.h>
61 #include <linux/crc32.h>
62 
63 #include <asm/system.h>
64 #include <asm/uaccess.h>
65 
66 #ifdef TUN_DEBUG
67 static int debug;
68 #endif
69 
70 /* Network device part of the driver */
71 
72 static LIST_HEAD(tun_dev_list);
73 static struct ethtool_ops tun_ethtool_ops;
74 
75 /* Net device open. */
76 static int tun_net_open(struct net_device *dev)
77 {
78 	netif_start_queue(dev);
79 	return 0;
80 }
81 
82 /* Net device close. */
83 static int tun_net_close(struct net_device *dev)
84 {
85 	netif_stop_queue(dev);
86 	return 0;
87 }
88 
89 /* Net device start xmit */
90 static int tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
91 {
92 	struct tun_struct *tun = netdev_priv(dev);
93 
94 	DBG(KERN_INFO "%s: tun_net_xmit %d\n", tun->dev->name, skb->len);
95 
96 	/* Drop packet if interface is not attached */
97 	if (!tun->attached)
98 		goto drop;
99 
100 	/* Packet dropping */
101 	if (skb_queue_len(&tun->readq) >= dev->tx_queue_len) {
102 		if (!(tun->flags & TUN_ONE_QUEUE)) {
103 			/* Normal queueing mode. */
104 			/* Packet scheduler handles dropping of further packets. */
105 			netif_stop_queue(dev);
106 
107 			/* We won't see all dropped packets individually, so overrun
108 			 * error is more appropriate. */
109 			tun->stats.tx_fifo_errors++;
110 		} else {
111 			/* Single queue mode.
112 			 * Driver handles dropping of all packets itself. */
113 			goto drop;
114 		}
115 	}
116 
117 	/* Queue packet */
118 	skb_queue_tail(&tun->readq, skb);
119 	dev->trans_start = jiffies;
120 
121 	/* Notify and wake up reader process */
122 	if (tun->flags & TUN_FASYNC)
123 		kill_fasync(&tun->fasync, SIGIO, POLL_IN);
124 	wake_up_interruptible(&tun->read_wait);
125 	return 0;
126 
127 drop:
128 	tun->stats.tx_dropped++;
129 	kfree_skb(skb);
130 	return 0;
131 }
132 
133 /** Add the specified Ethernet address to this multicast filter. */
134 static void
135 add_multi(u32* filter, const u8* addr)
136 {
137 	int bit_nr = ether_crc(ETH_ALEN, addr) >> 26;
138 	filter[bit_nr >> 5] |= 1 << (bit_nr & 31);
139 }
140 
141 /** Remove the specified Ethernet addres from this multicast filter. */
142 static void
143 del_multi(u32* filter, const u8* addr)
144 {
145 	int bit_nr = ether_crc(ETH_ALEN, addr) >> 26;
146 	filter[bit_nr >> 5] &= ~(1 << (bit_nr & 31));
147 }
148 
149 /** Update the list of multicast groups to which the network device belongs.
150  * This list is used to filter packets being sent from the character device to
151  * the network device. */
152 static void
153 tun_net_mclist(struct net_device *dev)
154 {
155 	struct tun_struct *tun = netdev_priv(dev);
156 	const struct dev_mc_list *mclist;
157 	int i;
158 	DBG(KERN_DEBUG "%s: tun_net_mclist: mc_count %d\n",
159 			dev->name, dev->mc_count);
160 	memset(tun->chr_filter, 0, sizeof tun->chr_filter);
161 	for (i = 0, mclist = dev->mc_list; i < dev->mc_count && mclist != NULL;
162 			i++, mclist = mclist->next) {
163 		add_multi(tun->net_filter, mclist->dmi_addr);
164 		DBG(KERN_DEBUG "%s: tun_net_mclist: %x:%x:%x:%x:%x:%x\n",
165 				dev->name,
166 				mclist->dmi_addr[0], mclist->dmi_addr[1], mclist->dmi_addr[2],
167 				mclist->dmi_addr[3], mclist->dmi_addr[4], mclist->dmi_addr[5]);
168 	}
169 }
170 
171 static struct net_device_stats *tun_net_stats(struct net_device *dev)
172 {
173 	struct tun_struct *tun = netdev_priv(dev);
174 	return &tun->stats;
175 }
176 
177 /* Initialize net device. */
178 static void tun_net_init(struct net_device *dev)
179 {
180 	struct tun_struct *tun = netdev_priv(dev);
181 
182 	switch (tun->flags & TUN_TYPE_MASK) {
183 	case TUN_TUN_DEV:
184 		/* Point-to-Point TUN Device */
185 		dev->hard_header_len = 0;
186 		dev->addr_len = 0;
187 		dev->mtu = 1500;
188 
189 		/* Zero header length */
190 		dev->type = ARPHRD_NONE;
191 		dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
192 		dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
193 		break;
194 
195 	case TUN_TAP_DEV:
196 		/* Ethernet TAP Device */
197 		dev->set_multicast_list = tun_net_mclist;
198 
199 		ether_setup(dev);
200 		random_ether_addr(dev->dev_addr);
201 		dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
202 		break;
203 	}
204 }
205 
206 /* Character device part */
207 
208 /* Poll */
209 static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
210 {
211 	struct tun_struct *tun = file->private_data;
212 	unsigned int mask = POLLOUT | POLLWRNORM;
213 
214 	if (!tun)
215 		return -EBADFD;
216 
217 	DBG(KERN_INFO "%s: tun_chr_poll\n", tun->dev->name);
218 
219 	poll_wait(file, &tun->read_wait, wait);
220 
221 	if (!skb_queue_empty(&tun->readq))
222 		mask |= POLLIN | POLLRDNORM;
223 
224 	return mask;
225 }
226 
227 /* Get packet from user space buffer */
228 static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct iovec *iv, size_t count)
229 {
230 	struct tun_pi pi = { 0, __constant_htons(ETH_P_IP) };
231 	struct sk_buff *skb;
232 	size_t len = count, align = 0;
233 
234 	if (!(tun->flags & TUN_NO_PI)) {
235 		if ((len -= sizeof(pi)) > count)
236 			return -EINVAL;
237 
238 		if(memcpy_fromiovec((void *)&pi, iv, sizeof(pi)))
239 			return -EFAULT;
240 	}
241 
242 	if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV)
243 		align = NET_IP_ALIGN;
244 
245 	if (!(skb = alloc_skb(len + align, GFP_KERNEL))) {
246 		tun->stats.rx_dropped++;
247 		return -ENOMEM;
248 	}
249 
250 	if (align)
251 		skb_reserve(skb, align);
252 	if (memcpy_fromiovec(skb_put(skb, len), iv, len)) {
253 		tun->stats.rx_dropped++;
254 		kfree_skb(skb);
255 		return -EFAULT;
256 	}
257 
258 	skb->dev = tun->dev;
259 	switch (tun->flags & TUN_TYPE_MASK) {
260 	case TUN_TUN_DEV:
261 		skb->mac.raw = skb->data;
262 		skb->protocol = pi.proto;
263 		break;
264 	case TUN_TAP_DEV:
265 		skb->protocol = eth_type_trans(skb, tun->dev);
266 		break;
267 	};
268 
269 	if (tun->flags & TUN_NOCHECKSUM)
270 		skb->ip_summed = CHECKSUM_UNNECESSARY;
271 
272 	netif_rx_ni(skb);
273 	tun->dev->last_rx = jiffies;
274 
275 	tun->stats.rx_packets++;
276 	tun->stats.rx_bytes += len;
277 
278 	return count;
279 }
280 
281 static inline size_t iov_total(const struct iovec *iv, unsigned long count)
282 {
283 	unsigned long i;
284 	size_t len;
285 
286 	for (i = 0, len = 0; i < count; i++)
287 		len += iv[i].iov_len;
288 
289 	return len;
290 }
291 
292 /* Writev */
293 static ssize_t tun_chr_writev(struct file * file, const struct iovec *iv,
294 			      unsigned long count, loff_t *pos)
295 {
296 	struct tun_struct *tun = file->private_data;
297 
298 	if (!tun)
299 		return -EBADFD;
300 
301 	DBG(KERN_INFO "%s: tun_chr_write %ld\n", tun->dev->name, count);
302 
303 	return tun_get_user(tun, (struct iovec *) iv, iov_total(iv, count));
304 }
305 
306 /* Write */
307 static ssize_t tun_chr_write(struct file * file, const char __user * buf,
308 			     size_t count, loff_t *pos)
309 {
310 	struct iovec iv = { (void __user *) buf, count };
311 	return tun_chr_writev(file, &iv, 1, pos);
312 }
313 
314 /* Put packet to the user space buffer */
315 static __inline__ ssize_t tun_put_user(struct tun_struct *tun,
316 				       struct sk_buff *skb,
317 				       struct iovec *iv, int len)
318 {
319 	struct tun_pi pi = { 0, skb->protocol };
320 	ssize_t total = 0;
321 
322 	if (!(tun->flags & TUN_NO_PI)) {
323 		if ((len -= sizeof(pi)) < 0)
324 			return -EINVAL;
325 
326 		if (len < skb->len) {
327 			/* Packet will be striped */
328 			pi.flags |= TUN_PKT_STRIP;
329 		}
330 
331 		if (memcpy_toiovec(iv, (void *) &pi, sizeof(pi)))
332 			return -EFAULT;
333 		total += sizeof(pi);
334 	}
335 
336 	len = min_t(int, skb->len, len);
337 
338 	skb_copy_datagram_iovec(skb, 0, iv, len);
339 	total += len;
340 
341 	tun->stats.tx_packets++;
342 	tun->stats.tx_bytes += len;
343 
344 	return total;
345 }
346 
347 /* Readv */
348 static ssize_t tun_chr_readv(struct file *file, const struct iovec *iv,
349 			    unsigned long count, loff_t *pos)
350 {
351 	struct tun_struct *tun = file->private_data;
352 	DECLARE_WAITQUEUE(wait, current);
353 	struct sk_buff *skb;
354 	ssize_t len, ret = 0;
355 
356 	if (!tun)
357 		return -EBADFD;
358 
359 	DBG(KERN_INFO "%s: tun_chr_read\n", tun->dev->name);
360 
361 	len = iov_total(iv, count);
362 	if (len < 0)
363 		return -EINVAL;
364 
365 	add_wait_queue(&tun->read_wait, &wait);
366 	while (len) {
367 		const u8 ones[ ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
368 		u8 addr[ ETH_ALEN];
369 		int bit_nr;
370 
371 		current->state = TASK_INTERRUPTIBLE;
372 
373 		/* Read frames from the queue */
374 		if (!(skb=skb_dequeue(&tun->readq))) {
375 			if (file->f_flags & O_NONBLOCK) {
376 				ret = -EAGAIN;
377 				break;
378 			}
379 			if (signal_pending(current)) {
380 				ret = -ERESTARTSYS;
381 				break;
382 			}
383 
384 			/* Nothing to read, let's sleep */
385 			schedule();
386 			continue;
387 		}
388 		netif_wake_queue(tun->dev);
389 
390 		/** Decide whether to accept this packet. This code is designed to
391 		 * behave identically to an Ethernet interface. Accept the packet if
392 		 * - we are promiscuous.
393 		 * - the packet is addressed to us.
394 		 * - the packet is broadcast.
395 		 * - the packet is multicast and
396 		 *   - we are multicast promiscous.
397 		 *   - we belong to the multicast group.
398 		 */
399 		memcpy(addr, skb->data,
400 		       min_t(size_t, sizeof addr, skb->len));
401 		bit_nr = ether_crc(sizeof addr, addr) >> 26;
402 		if ((tun->if_flags & IFF_PROMISC) ||
403 				memcmp(addr, tun->dev_addr, sizeof addr) == 0 ||
404 				memcmp(addr, ones, sizeof addr) == 0 ||
405 				(((addr[0] == 1 && addr[1] == 0 && addr[2] == 0x5e) ||
406 				  (addr[0] == 0x33 && addr[1] == 0x33)) &&
407 				 ((tun->if_flags & IFF_ALLMULTI) ||
408 				  (tun->chr_filter[bit_nr >> 5] & (1 << (bit_nr & 31)))))) {
409 			DBG(KERN_DEBUG "%s: tun_chr_readv: accepted: %x:%x:%x:%x:%x:%x\n",
410 					tun->dev->name, addr[0], addr[1], addr[2],
411 					addr[3], addr[4], addr[5]);
412 			ret = tun_put_user(tun, skb, (struct iovec *) iv, len);
413 			kfree_skb(skb);
414 			break;
415 		} else {
416 			DBG(KERN_DEBUG "%s: tun_chr_readv: rejected: %x:%x:%x:%x:%x:%x\n",
417 					tun->dev->name, addr[0], addr[1], addr[2],
418 					addr[3], addr[4], addr[5]);
419 			kfree_skb(skb);
420 			continue;
421 		}
422 	}
423 
424 	current->state = TASK_RUNNING;
425 	remove_wait_queue(&tun->read_wait, &wait);
426 
427 	return ret;
428 }
429 
430 /* Read */
431 static ssize_t tun_chr_read(struct file * file, char __user * buf,
432 			    size_t count, loff_t *pos)
433 {
434 	struct iovec iv = { buf, count };
435 	return tun_chr_readv(file, &iv, 1, pos);
436 }
437 
438 static void tun_setup(struct net_device *dev)
439 {
440 	struct tun_struct *tun = netdev_priv(dev);
441 
442 	skb_queue_head_init(&tun->readq);
443 	init_waitqueue_head(&tun->read_wait);
444 
445 	tun->owner = -1;
446 
447 	SET_MODULE_OWNER(dev);
448 	dev->open = tun_net_open;
449 	dev->hard_start_xmit = tun_net_xmit;
450 	dev->stop = tun_net_close;
451 	dev->get_stats = tun_net_stats;
452 	dev->ethtool_ops = &tun_ethtool_ops;
453 	dev->destructor = free_netdev;
454 }
455 
456 static struct tun_struct *tun_get_by_name(const char *name)
457 {
458 	struct tun_struct *tun;
459 
460 	ASSERT_RTNL();
461 	list_for_each_entry(tun, &tun_dev_list, list) {
462 		if (!strncmp(tun->dev->name, name, IFNAMSIZ))
463 		    return tun;
464 	}
465 
466 	return NULL;
467 }
468 
469 static int tun_set_iff(struct file *file, struct ifreq *ifr)
470 {
471 	struct tun_struct *tun;
472 	struct net_device *dev;
473 	int err;
474 
475 	tun = tun_get_by_name(ifr->ifr_name);
476 	if (tun) {
477 		if (tun->attached)
478 			return -EBUSY;
479 
480 		/* Check permissions */
481 		if (tun->owner != -1 &&
482 		    current->euid != tun->owner && !capable(CAP_NET_ADMIN))
483 			return -EPERM;
484 	}
485 	else if (__dev_get_by_name(ifr->ifr_name))
486 		return -EINVAL;
487 	else {
488 		char *name;
489 		unsigned long flags = 0;
490 
491 		err = -EINVAL;
492 
493 		/* Set dev type */
494 		if (ifr->ifr_flags & IFF_TUN) {
495 			/* TUN device */
496 			flags |= TUN_TUN_DEV;
497 			name = "tun%d";
498 		} else if (ifr->ifr_flags & IFF_TAP) {
499 			/* TAP device */
500 			flags |= TUN_TAP_DEV;
501 			name = "tap%d";
502 		} else
503 			goto failed;
504 
505 		if (*ifr->ifr_name)
506 			name = ifr->ifr_name;
507 
508 		dev = alloc_netdev(sizeof(struct tun_struct), name,
509 				   tun_setup);
510 		if (!dev)
511 			return -ENOMEM;
512 
513 		tun = netdev_priv(dev);
514 		tun->dev = dev;
515 		tun->flags = flags;
516 		/* Be promiscuous by default to maintain previous behaviour. */
517 		tun->if_flags = IFF_PROMISC;
518 		/* Generate random Ethernet address. */
519 		*(u16 *)tun->dev_addr = htons(0x00FF);
520 		get_random_bytes(tun->dev_addr + sizeof(u16), 4);
521 		memset(tun->chr_filter, 0, sizeof tun->chr_filter);
522 
523 		tun_net_init(dev);
524 
525 		if (strchr(dev->name, '%')) {
526 			err = dev_alloc_name(dev, dev->name);
527 			if (err < 0)
528 				goto err_free_dev;
529 		}
530 
531 		err = register_netdevice(tun->dev);
532 		if (err < 0)
533 			goto err_free_dev;
534 
535 		list_add(&tun->list, &tun_dev_list);
536 	}
537 
538 	DBG(KERN_INFO "%s: tun_set_iff\n", tun->dev->name);
539 
540 	if (ifr->ifr_flags & IFF_NO_PI)
541 		tun->flags |= TUN_NO_PI;
542 
543 	if (ifr->ifr_flags & IFF_ONE_QUEUE)
544 		tun->flags |= TUN_ONE_QUEUE;
545 
546 	file->private_data = tun;
547 	tun->attached = 1;
548 
549 	strcpy(ifr->ifr_name, tun->dev->name);
550 	return 0;
551 
552  err_free_dev:
553 	free_netdev(dev);
554  failed:
555 	return err;
556 }
557 
558 static int tun_chr_ioctl(struct inode *inode, struct file *file,
559 			 unsigned int cmd, unsigned long arg)
560 {
561 	struct tun_struct *tun = file->private_data;
562 	void __user* argp = (void __user*)arg;
563 	struct ifreq ifr;
564 
565 	if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
566 		if (copy_from_user(&ifr, argp, sizeof ifr))
567 			return -EFAULT;
568 
569 	if (cmd == TUNSETIFF && !tun) {
570 		int err;
571 
572 		ifr.ifr_name[IFNAMSIZ-1] = '\0';
573 
574 		rtnl_lock();
575 		err = tun_set_iff(file, &ifr);
576 		rtnl_unlock();
577 
578 		if (err)
579 			return err;
580 
581 		if (copy_to_user(argp, &ifr, sizeof(ifr)))
582 			return -EFAULT;
583 		return 0;
584 	}
585 
586 	if (!tun)
587 		return -EBADFD;
588 
589 	DBG(KERN_INFO "%s: tun_chr_ioctl cmd %d\n", tun->dev->name, cmd);
590 
591 	switch (cmd) {
592 	case TUNSETNOCSUM:
593 		/* Disable/Enable checksum */
594 		if (arg)
595 			tun->flags |= TUN_NOCHECKSUM;
596 		else
597 			tun->flags &= ~TUN_NOCHECKSUM;
598 
599 		DBG(KERN_INFO "%s: checksum %s\n",
600 		    tun->dev->name, arg ? "disabled" : "enabled");
601 		break;
602 
603 	case TUNSETPERSIST:
604 		/* Disable/Enable persist mode */
605 		if (arg)
606 			tun->flags |= TUN_PERSIST;
607 		else
608 			tun->flags &= ~TUN_PERSIST;
609 
610 		DBG(KERN_INFO "%s: persist %s\n",
611 		    tun->dev->name, arg ? "disabled" : "enabled");
612 		break;
613 
614 	case TUNSETOWNER:
615 		/* Set owner of the device */
616 		tun->owner = (uid_t) arg;
617 
618 		DBG(KERN_INFO "%s: owner set to %d\n", tun->dev->name, tun->owner);
619 		break;
620 
621 	case TUNSETLINK:
622 		/* Only allow setting the type when the interface is down */
623 		if (tun->dev->flags & IFF_UP) {
624 			DBG(KERN_INFO "%s: Linktype set failed because interface is up\n",
625 				tun->dev->name);
626 			return -EBUSY;
627 		} else {
628 			tun->dev->type = (int) arg;
629 			DBG(KERN_INFO "%s: linktype set to %d\n", tun->dev->name, tun->dev->type);
630 		}
631 		break;
632 
633 #ifdef TUN_DEBUG
634 	case TUNSETDEBUG:
635 		tun->debug = arg;
636 		break;
637 #endif
638 
639 	case SIOCGIFFLAGS:
640 		ifr.ifr_flags = tun->if_flags;
641 		if (copy_to_user( argp, &ifr, sizeof ifr))
642 			return -EFAULT;
643 		return 0;
644 
645 	case SIOCSIFFLAGS:
646 		/** Set the character device's interface flags. Currently only
647 		 * IFF_PROMISC and IFF_ALLMULTI are used. */
648 		tun->if_flags = ifr.ifr_flags;
649 		DBG(KERN_INFO "%s: interface flags 0x%lx\n",
650 				tun->dev->name, tun->if_flags);
651 		return 0;
652 
653 	case SIOCGIFHWADDR:
654 		memcpy(ifr.ifr_hwaddr.sa_data, tun->dev_addr,
655 				min(sizeof ifr.ifr_hwaddr.sa_data, sizeof tun->dev_addr));
656 		if (copy_to_user( argp, &ifr, sizeof ifr))
657 			return -EFAULT;
658 		return 0;
659 
660 	case SIOCSIFHWADDR:
661 		/** Set the character device's hardware address. This is used when
662 		 * filtering packets being sent from the network device to the character
663 		 * device. */
664 		memcpy(tun->dev_addr, ifr.ifr_hwaddr.sa_data,
665 				min(sizeof ifr.ifr_hwaddr.sa_data, sizeof tun->dev_addr));
666 		DBG(KERN_DEBUG "%s: set hardware address: %x:%x:%x:%x:%x:%x\n",
667 				tun->dev->name,
668 				tun->dev_addr[0], tun->dev_addr[1], tun->dev_addr[2],
669 				tun->dev_addr[3], tun->dev_addr[4], tun->dev_addr[5]);
670 		return 0;
671 
672 	case SIOCADDMULTI:
673 		/** Add the specified group to the character device's multicast filter
674 		 * list. */
675 		add_multi(tun->chr_filter, ifr.ifr_hwaddr.sa_data);
676 		DBG(KERN_DEBUG "%s: add multi: %x:%x:%x:%x:%x:%x\n",
677 				tun->dev->name,
678 				(u8)ifr.ifr_hwaddr.sa_data[0], (u8)ifr.ifr_hwaddr.sa_data[1],
679 				(u8)ifr.ifr_hwaddr.sa_data[2], (u8)ifr.ifr_hwaddr.sa_data[3],
680 				(u8)ifr.ifr_hwaddr.sa_data[4], (u8)ifr.ifr_hwaddr.sa_data[5]);
681 		return 0;
682 
683 	case SIOCDELMULTI:
684 		/** Remove the specified group from the character device's multicast
685 		 * filter list. */
686 		del_multi(tun->chr_filter, ifr.ifr_hwaddr.sa_data);
687 		DBG(KERN_DEBUG "%s: del multi: %x:%x:%x:%x:%x:%x\n",
688 				tun->dev->name,
689 				(u8)ifr.ifr_hwaddr.sa_data[0], (u8)ifr.ifr_hwaddr.sa_data[1],
690 				(u8)ifr.ifr_hwaddr.sa_data[2], (u8)ifr.ifr_hwaddr.sa_data[3],
691 				(u8)ifr.ifr_hwaddr.sa_data[4], (u8)ifr.ifr_hwaddr.sa_data[5]);
692 		return 0;
693 
694 	default:
695 		return -EINVAL;
696 	};
697 
698 	return 0;
699 }
700 
701 static int tun_chr_fasync(int fd, struct file *file, int on)
702 {
703 	struct tun_struct *tun = file->private_data;
704 	int ret;
705 
706 	if (!tun)
707 		return -EBADFD;
708 
709 	DBG(KERN_INFO "%s: tun_chr_fasync %d\n", tun->dev->name, on);
710 
711 	if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
712 		return ret;
713 
714 	if (on) {
715 		ret = f_setown(file, current->pid, 0);
716 		if (ret)
717 			return ret;
718 		tun->flags |= TUN_FASYNC;
719 	} else
720 		tun->flags &= ~TUN_FASYNC;
721 
722 	return 0;
723 }
724 
725 static int tun_chr_open(struct inode *inode, struct file * file)
726 {
727 	DBG1(KERN_INFO "tunX: tun_chr_open\n");
728 	file->private_data = NULL;
729 	return 0;
730 }
731 
732 static int tun_chr_close(struct inode *inode, struct file *file)
733 {
734 	struct tun_struct *tun = file->private_data;
735 
736 	if (!tun)
737 		return 0;
738 
739 	DBG(KERN_INFO "%s: tun_chr_close\n", tun->dev->name);
740 
741 	tun_chr_fasync(-1, file, 0);
742 
743 	rtnl_lock();
744 
745 	/* Detach from net device */
746 	file->private_data = NULL;
747 	tun->attached = 0;
748 
749 	/* Drop read queue */
750 	skb_queue_purge(&tun->readq);
751 
752 	if (!(tun->flags & TUN_PERSIST)) {
753 		list_del(&tun->list);
754 		unregister_netdevice(tun->dev);
755 	}
756 
757 	rtnl_unlock();
758 
759 	return 0;
760 }
761 
762 static struct file_operations tun_fops = {
763 	.owner	= THIS_MODULE,
764 	.llseek = no_llseek,
765 	.read	= tun_chr_read,
766 	.readv	= tun_chr_readv,
767 	.write	= tun_chr_write,
768 	.writev = tun_chr_writev,
769 	.poll	= tun_chr_poll,
770 	.ioctl	= tun_chr_ioctl,
771 	.open	= tun_chr_open,
772 	.release = tun_chr_close,
773 	.fasync = tun_chr_fasync
774 };
775 
776 static struct miscdevice tun_miscdev = {
777 	.minor = TUN_MINOR,
778 	.name = "tun",
779 	.fops = &tun_fops,
780 	.devfs_name = "net/tun",
781 };
782 
783 /* ethtool interface */
784 
785 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
786 {
787 	cmd->supported		= 0;
788 	cmd->advertising	= 0;
789 	cmd->speed		= SPEED_10;
790 	cmd->duplex		= DUPLEX_FULL;
791 	cmd->port		= PORT_TP;
792 	cmd->phy_address	= 0;
793 	cmd->transceiver	= XCVR_INTERNAL;
794 	cmd->autoneg		= AUTONEG_DISABLE;
795 	cmd->maxtxpkt		= 0;
796 	cmd->maxrxpkt		= 0;
797 	return 0;
798 }
799 
800 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
801 {
802 	struct tun_struct *tun = netdev_priv(dev);
803 
804 	strcpy(info->driver, DRV_NAME);
805 	strcpy(info->version, DRV_VERSION);
806 	strcpy(info->fw_version, "N/A");
807 
808 	switch (tun->flags & TUN_TYPE_MASK) {
809 	case TUN_TUN_DEV:
810 		strcpy(info->bus_info, "tun");
811 		break;
812 	case TUN_TAP_DEV:
813 		strcpy(info->bus_info, "tap");
814 		break;
815 	}
816 }
817 
818 static u32 tun_get_msglevel(struct net_device *dev)
819 {
820 #ifdef TUN_DEBUG
821 	struct tun_struct *tun = netdev_priv(dev);
822 	return tun->debug;
823 #else
824 	return -EOPNOTSUPP;
825 #endif
826 }
827 
828 static void tun_set_msglevel(struct net_device *dev, u32 value)
829 {
830 #ifdef TUN_DEBUG
831 	struct tun_struct *tun = netdev_priv(dev);
832 	tun->debug = value;
833 #endif
834 }
835 
836 static u32 tun_get_link(struct net_device *dev)
837 {
838 	struct tun_struct *tun = netdev_priv(dev);
839 	return tun->attached;
840 }
841 
842 static u32 tun_get_rx_csum(struct net_device *dev)
843 {
844 	struct tun_struct *tun = netdev_priv(dev);
845 	return (tun->flags & TUN_NOCHECKSUM) == 0;
846 }
847 
848 static int tun_set_rx_csum(struct net_device *dev, u32 data)
849 {
850 	struct tun_struct *tun = netdev_priv(dev);
851 	if (data)
852 		tun->flags &= ~TUN_NOCHECKSUM;
853 	else
854 		tun->flags |= TUN_NOCHECKSUM;
855 	return 0;
856 }
857 
858 static struct ethtool_ops tun_ethtool_ops = {
859 	.get_settings	= tun_get_settings,
860 	.get_drvinfo	= tun_get_drvinfo,
861 	.get_msglevel	= tun_get_msglevel,
862 	.set_msglevel	= tun_set_msglevel,
863 	.get_link	= tun_get_link,
864 	.get_rx_csum	= tun_get_rx_csum,
865 	.set_rx_csum	= tun_set_rx_csum
866 };
867 
868 static int __init tun_init(void)
869 {
870 	int ret = 0;
871 
872 	printk(KERN_INFO "tun: %s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
873 	printk(KERN_INFO "tun: %s\n", DRV_COPYRIGHT);
874 
875 	ret = misc_register(&tun_miscdev);
876 	if (ret)
877 		printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR);
878 	return ret;
879 }
880 
881 static void tun_cleanup(void)
882 {
883 	struct tun_struct *tun, *nxt;
884 
885 	misc_deregister(&tun_miscdev);
886 
887 	rtnl_lock();
888 	list_for_each_entry_safe(tun, nxt, &tun_dev_list, list) {
889 		DBG(KERN_INFO "%s cleaned up\n", tun->dev->name);
890 		unregister_netdevice(tun->dev);
891 	}
892 	rtnl_unlock();
893 
894 }
895 
896 module_init(tun_init);
897 module_exit(tun_cleanup);
898 MODULE_DESCRIPTION(DRV_DESCRIPTION);
899 MODULE_AUTHOR(DRV_COPYRIGHT);
900 MODULE_LICENSE("GPL");
901 MODULE_ALIAS_MISCDEV(TUN_MINOR);
902