xref: /linux/net/core/dev.c (revision de2fe5e07d58424bc286fff3fd3c1b0bf933cd58)
1 /*
2  * 	NET3	Protocol independent device support routines.
3  *
4  *		This program is free software; you can redistribute it and/or
5  *		modify it under the terms of the GNU General Public License
6  *		as published by the Free Software Foundation; either version
7  *		2 of the License, or (at your option) any later version.
8  *
9  *	Derived from the non IP parts of dev.c 1.0.19
10  * 		Authors:	Ross Biro
11  *				Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12  *				Mark Evans, <evansmp@uhura.aston.ac.uk>
13  *
14  *	Additional Authors:
15  *		Florian la Roche <rzsfl@rz.uni-sb.de>
16  *		Alan Cox <gw4pts@gw4pts.ampr.org>
17  *		David Hinds <dahinds@users.sourceforge.net>
18  *		Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
19  *		Adam Sulmicki <adam@cfar.umd.edu>
20  *              Pekka Riikonen <priikone@poesidon.pspt.fi>
21  *
22  *	Changes:
23  *              D.J. Barrow     :       Fixed bug where dev->refcnt gets set
24  *              			to 2 if register_netdev gets called
25  *              			before net_dev_init & also removed a
26  *              			few lines of code in the process.
27  *		Alan Cox	:	device private ioctl copies fields back.
28  *		Alan Cox	:	Transmit queue code does relevant
29  *					stunts to keep the queue safe.
30  *		Alan Cox	:	Fixed double lock.
31  *		Alan Cox	:	Fixed promisc NULL pointer trap
32  *		????????	:	Support the full private ioctl range
33  *		Alan Cox	:	Moved ioctl permission check into
34  *					drivers
35  *		Tim Kordas	:	SIOCADDMULTI/SIOCDELMULTI
36  *		Alan Cox	:	100 backlog just doesn't cut it when
37  *					you start doing multicast video 8)
38  *		Alan Cox	:	Rewrote net_bh and list manager.
39  *		Alan Cox	: 	Fix ETH_P_ALL echoback lengths.
40  *		Alan Cox	:	Took out transmit every packet pass
41  *					Saved a few bytes in the ioctl handler
42  *		Alan Cox	:	Network driver sets packet type before
43  *					calling netif_rx. Saves a function
44  *					call a packet.
45  *		Alan Cox	:	Hashed net_bh()
46  *		Richard Kooijman:	Timestamp fixes.
47  *		Alan Cox	:	Wrong field in SIOCGIFDSTADDR
48  *		Alan Cox	:	Device lock protection.
49  *		Alan Cox	: 	Fixed nasty side effect of device close
50  *					changes.
51  *		Rudi Cilibrasi	:	Pass the right thing to
52  *					set_mac_address()
53  *		Dave Miller	:	32bit quantity for the device lock to
54  *					make it work out on a Sparc.
55  *		Bjorn Ekwall	:	Added KERNELD hack.
56  *		Alan Cox	:	Cleaned up the backlog initialise.
57  *		Craig Metz	:	SIOCGIFCONF fix if space for under
58  *					1 device.
59  *	    Thomas Bogendoerfer :	Return ENODEV for dev_open, if there
60  *					is no device open function.
61  *		Andi Kleen	:	Fix error reporting for SIOCGIFCONF
62  *	    Michael Chastain	:	Fix signed/unsigned for SIOCGIFCONF
63  *		Cyrus Durgin	:	Cleaned for KMOD
64  *		Adam Sulmicki   :	Bug Fix : Network Device Unload
65  *					A network device unload needs to purge
66  *					the backlog queue.
67  *	Paul Rusty Russell	:	SIOCSIFNAME
68  *              Pekka Riikonen  :	Netdev boot-time settings code
69  *              Andrew Morton   :       Make unregister_netdevice wait
70  *              			indefinitely on dev->refcnt
71  * 		J Hadi Salim	:	- Backlog queue sampling
72  *				        - netif_rx() feedback
73  */
74 
75 #include <asm/uaccess.h>
76 #include <asm/system.h>
77 #include <linux/bitops.h>
78 #include <linux/capability.h>
79 #include <linux/config.h>
80 #include <linux/cpu.h>
81 #include <linux/types.h>
82 #include <linux/kernel.h>
83 #include <linux/sched.h>
84 #include <linux/mutex.h>
85 #include <linux/string.h>
86 #include <linux/mm.h>
87 #include <linux/socket.h>
88 #include <linux/sockios.h>
89 #include <linux/errno.h>
90 #include <linux/interrupt.h>
91 #include <linux/if_ether.h>
92 #include <linux/netdevice.h>
93 #include <linux/etherdevice.h>
94 #include <linux/notifier.h>
95 #include <linux/skbuff.h>
96 #include <net/sock.h>
97 #include <linux/rtnetlink.h>
98 #include <linux/proc_fs.h>
99 #include <linux/seq_file.h>
100 #include <linux/stat.h>
101 #include <linux/if_bridge.h>
102 #include <linux/divert.h>
103 #include <net/dst.h>
104 #include <net/pkt_sched.h>
105 #include <net/checksum.h>
106 #include <linux/highmem.h>
107 #include <linux/init.h>
108 #include <linux/kmod.h>
109 #include <linux/module.h>
110 #include <linux/kallsyms.h>
111 #include <linux/netpoll.h>
112 #include <linux/rcupdate.h>
113 #include <linux/delay.h>
114 #include <linux/wireless.h>
115 #include <net/iw_handler.h>
116 #include <asm/current.h>
117 #include <linux/audit.h>
118 
119 /*
120  *	The list of packet types we will receive (as opposed to discard)
121  *	and the routines to invoke.
122  *
123  *	Why 16. Because with 16 the only overlap we get on a hash of the
124  *	low nibble of the protocol value is RARP/SNAP/X.25.
125  *
126  *      NOTE:  That is no longer true with the addition of VLAN tags.  Not
127  *             sure which should go first, but I bet it won't make much
128  *             difference if we are running VLANs.  The good news is that
129  *             this protocol won't be in the list unless compiled in, so
130  *             the average user (w/out VLANs) will not be adversly affected.
131  *             --BLG
132  *
133  *		0800	IP
134  *		8100    802.1Q VLAN
135  *		0001	802.3
136  *		0002	AX.25
137  *		0004	802.2
138  *		8035	RARP
139  *		0005	SNAP
140  *		0805	X.25
141  *		0806	ARP
142  *		8137	IPX
143  *		0009	Localtalk
144  *		86DD	IPv6
145  */
146 
147 static DEFINE_SPINLOCK(ptype_lock);
148 static struct list_head ptype_base[16];	/* 16 way hashed list */
149 static struct list_head ptype_all;		/* Taps */
150 
151 /*
152  * The @dev_base list is protected by @dev_base_lock and the rtln
153  * semaphore.
154  *
155  * Pure readers hold dev_base_lock for reading.
156  *
157  * Writers must hold the rtnl semaphore while they loop through the
158  * dev_base list, and hold dev_base_lock for writing when they do the
159  * actual updates.  This allows pure readers to access the list even
160  * while a writer is preparing to update it.
161  *
162  * To put it another way, dev_base_lock is held for writing only to
163  * protect against pure readers; the rtnl semaphore provides the
164  * protection against other writers.
165  *
166  * See, for example usages, register_netdevice() and
167  * unregister_netdevice(), which must be called with the rtnl
168  * semaphore held.
169  */
170 struct net_device *dev_base;
171 static struct net_device **dev_tail = &dev_base;
172 DEFINE_RWLOCK(dev_base_lock);
173 
174 EXPORT_SYMBOL(dev_base);
175 EXPORT_SYMBOL(dev_base_lock);
176 
177 #define NETDEV_HASHBITS	8
178 static struct hlist_head dev_name_head[1<<NETDEV_HASHBITS];
179 static struct hlist_head dev_index_head[1<<NETDEV_HASHBITS];
180 
181 static inline struct hlist_head *dev_name_hash(const char *name)
182 {
183 	unsigned hash = full_name_hash(name, strnlen(name, IFNAMSIZ));
184 	return &dev_name_head[hash & ((1<<NETDEV_HASHBITS)-1)];
185 }
186 
187 static inline struct hlist_head *dev_index_hash(int ifindex)
188 {
189 	return &dev_index_head[ifindex & ((1<<NETDEV_HASHBITS)-1)];
190 }
191 
192 /*
193  *	Our notifier list
194  */
195 
196 static BLOCKING_NOTIFIER_HEAD(netdev_chain);
197 
198 /*
199  *	Device drivers call our routines to queue packets here. We empty the
200  *	queue in the local softnet handler.
201  */
202 DEFINE_PER_CPU(struct softnet_data, softnet_data) = { NULL };
203 
204 #ifdef CONFIG_SYSFS
205 extern int netdev_sysfs_init(void);
206 extern int netdev_register_sysfs(struct net_device *);
207 extern void netdev_unregister_sysfs(struct net_device *);
208 #else
209 #define netdev_sysfs_init()	 	(0)
210 #define netdev_register_sysfs(dev)	(0)
211 #define	netdev_unregister_sysfs(dev)	do { } while(0)
212 #endif
213 
214 
215 /*******************************************************************************
216 
217 		Protocol management and registration routines
218 
219 *******************************************************************************/
220 
221 /*
222  *	For efficiency
223  */
224 
225 int netdev_nit;
226 
227 /*
228  *	Add a protocol ID to the list. Now that the input handler is
229  *	smarter we can dispense with all the messy stuff that used to be
230  *	here.
231  *
232  *	BEWARE!!! Protocol handlers, mangling input packets,
233  *	MUST BE last in hash buckets and checking protocol handlers
234  *	MUST start from promiscuous ptype_all chain in net_bh.
235  *	It is true now, do not change it.
236  *	Explanation follows: if protocol handler, mangling packet, will
237  *	be the first on list, it is not able to sense, that packet
238  *	is cloned and should be copied-on-write, so that it will
239  *	change it and subsequent readers will get broken packet.
240  *							--ANK (980803)
241  */
242 
243 /**
244  *	dev_add_pack - add packet handler
245  *	@pt: packet type declaration
246  *
247  *	Add a protocol handler to the networking stack. The passed &packet_type
248  *	is linked into kernel lists and may not be freed until it has been
249  *	removed from the kernel lists.
250  *
251  *	This call does not sleep therefore it can not
252  *	guarantee all CPU's that are in middle of receiving packets
253  *	will see the new packet type (until the next received packet).
254  */
255 
256 void dev_add_pack(struct packet_type *pt)
257 {
258 	int hash;
259 
260 	spin_lock_bh(&ptype_lock);
261 	if (pt->type == htons(ETH_P_ALL)) {
262 		netdev_nit++;
263 		list_add_rcu(&pt->list, &ptype_all);
264 	} else {
265 		hash = ntohs(pt->type) & 15;
266 		list_add_rcu(&pt->list, &ptype_base[hash]);
267 	}
268 	spin_unlock_bh(&ptype_lock);
269 }
270 
271 /**
272  *	__dev_remove_pack	 - remove packet handler
273  *	@pt: packet type declaration
274  *
275  *	Remove a protocol handler that was previously added to the kernel
276  *	protocol handlers by dev_add_pack(). The passed &packet_type is removed
277  *	from the kernel lists and can be freed or reused once this function
278  *	returns.
279  *
280  *      The packet type might still be in use by receivers
281  *	and must not be freed until after all the CPU's have gone
282  *	through a quiescent state.
283  */
284 void __dev_remove_pack(struct packet_type *pt)
285 {
286 	struct list_head *head;
287 	struct packet_type *pt1;
288 
289 	spin_lock_bh(&ptype_lock);
290 
291 	if (pt->type == htons(ETH_P_ALL)) {
292 		netdev_nit--;
293 		head = &ptype_all;
294 	} else
295 		head = &ptype_base[ntohs(pt->type) & 15];
296 
297 	list_for_each_entry(pt1, head, list) {
298 		if (pt == pt1) {
299 			list_del_rcu(&pt->list);
300 			goto out;
301 		}
302 	}
303 
304 	printk(KERN_WARNING "dev_remove_pack: %p not found.\n", pt);
305 out:
306 	spin_unlock_bh(&ptype_lock);
307 }
308 /**
309  *	dev_remove_pack	 - remove packet handler
310  *	@pt: packet type declaration
311  *
312  *	Remove a protocol handler that was previously added to the kernel
313  *	protocol handlers by dev_add_pack(). The passed &packet_type is removed
314  *	from the kernel lists and can be freed or reused once this function
315  *	returns.
316  *
317  *	This call sleeps to guarantee that no CPU is looking at the packet
318  *	type after return.
319  */
320 void dev_remove_pack(struct packet_type *pt)
321 {
322 	__dev_remove_pack(pt);
323 
324 	synchronize_net();
325 }
326 
327 /******************************************************************************
328 
329 		      Device Boot-time Settings Routines
330 
331 *******************************************************************************/
332 
333 /* Boot time configuration table */
334 static struct netdev_boot_setup dev_boot_setup[NETDEV_BOOT_SETUP_MAX];
335 
336 /**
337  *	netdev_boot_setup_add	- add new setup entry
338  *	@name: name of the device
339  *	@map: configured settings for the device
340  *
341  *	Adds new setup entry to the dev_boot_setup list.  The function
342  *	returns 0 on error and 1 on success.  This is a generic routine to
343  *	all netdevices.
344  */
345 static int netdev_boot_setup_add(char *name, struct ifmap *map)
346 {
347 	struct netdev_boot_setup *s;
348 	int i;
349 
350 	s = dev_boot_setup;
351 	for (i = 0; i < NETDEV_BOOT_SETUP_MAX; i++) {
352 		if (s[i].name[0] == '\0' || s[i].name[0] == ' ') {
353 			memset(s[i].name, 0, sizeof(s[i].name));
354 			strcpy(s[i].name, name);
355 			memcpy(&s[i].map, map, sizeof(s[i].map));
356 			break;
357 		}
358 	}
359 
360 	return i >= NETDEV_BOOT_SETUP_MAX ? 0 : 1;
361 }
362 
363 /**
364  *	netdev_boot_setup_check	- check boot time settings
365  *	@dev: the netdevice
366  *
367  * 	Check boot time settings for the device.
368  *	The found settings are set for the device to be used
369  *	later in the device probing.
370  *	Returns 0 if no settings found, 1 if they are.
371  */
372 int netdev_boot_setup_check(struct net_device *dev)
373 {
374 	struct netdev_boot_setup *s = dev_boot_setup;
375 	int i;
376 
377 	for (i = 0; i < NETDEV_BOOT_SETUP_MAX; i++) {
378 		if (s[i].name[0] != '\0' && s[i].name[0] != ' ' &&
379 		    !strncmp(dev->name, s[i].name, strlen(s[i].name))) {
380 			dev->irq 	= s[i].map.irq;
381 			dev->base_addr 	= s[i].map.base_addr;
382 			dev->mem_start 	= s[i].map.mem_start;
383 			dev->mem_end 	= s[i].map.mem_end;
384 			return 1;
385 		}
386 	}
387 	return 0;
388 }
389 
390 
391 /**
392  *	netdev_boot_base	- get address from boot time settings
393  *	@prefix: prefix for network device
394  *	@unit: id for network device
395  *
396  * 	Check boot time settings for the base address of device.
397  *	The found settings are set for the device to be used
398  *	later in the device probing.
399  *	Returns 0 if no settings found.
400  */
401 unsigned long netdev_boot_base(const char *prefix, int unit)
402 {
403 	const struct netdev_boot_setup *s = dev_boot_setup;
404 	char name[IFNAMSIZ];
405 	int i;
406 
407 	sprintf(name, "%s%d", prefix, unit);
408 
409 	/*
410 	 * If device already registered then return base of 1
411 	 * to indicate not to probe for this interface
412 	 */
413 	if (__dev_get_by_name(name))
414 		return 1;
415 
416 	for (i = 0; i < NETDEV_BOOT_SETUP_MAX; i++)
417 		if (!strcmp(name, s[i].name))
418 			return s[i].map.base_addr;
419 	return 0;
420 }
421 
422 /*
423  * Saves at boot time configured settings for any netdevice.
424  */
425 int __init netdev_boot_setup(char *str)
426 {
427 	int ints[5];
428 	struct ifmap map;
429 
430 	str = get_options(str, ARRAY_SIZE(ints), ints);
431 	if (!str || !*str)
432 		return 0;
433 
434 	/* Save settings */
435 	memset(&map, 0, sizeof(map));
436 	if (ints[0] > 0)
437 		map.irq = ints[1];
438 	if (ints[0] > 1)
439 		map.base_addr = ints[2];
440 	if (ints[0] > 2)
441 		map.mem_start = ints[3];
442 	if (ints[0] > 3)
443 		map.mem_end = ints[4];
444 
445 	/* Add new entry to the list */
446 	return netdev_boot_setup_add(str, &map);
447 }
448 
449 __setup("netdev=", netdev_boot_setup);
450 
451 /*******************************************************************************
452 
453 			    Device Interface Subroutines
454 
455 *******************************************************************************/
456 
457 /**
458  *	__dev_get_by_name	- find a device by its name
459  *	@name: name to find
460  *
461  *	Find an interface by name. Must be called under RTNL semaphore
462  *	or @dev_base_lock. If the name is found a pointer to the device
463  *	is returned. If the name is not found then %NULL is returned. The
464  *	reference counters are not incremented so the caller must be
465  *	careful with locks.
466  */
467 
468 struct net_device *__dev_get_by_name(const char *name)
469 {
470 	struct hlist_node *p;
471 
472 	hlist_for_each(p, dev_name_hash(name)) {
473 		struct net_device *dev
474 			= hlist_entry(p, struct net_device, name_hlist);
475 		if (!strncmp(dev->name, name, IFNAMSIZ))
476 			return dev;
477 	}
478 	return NULL;
479 }
480 
481 /**
482  *	dev_get_by_name		- find a device by its name
483  *	@name: name to find
484  *
485  *	Find an interface by name. This can be called from any
486  *	context and does its own locking. The returned handle has
487  *	the usage count incremented and the caller must use dev_put() to
488  *	release it when it is no longer needed. %NULL is returned if no
489  *	matching device is found.
490  */
491 
492 struct net_device *dev_get_by_name(const char *name)
493 {
494 	struct net_device *dev;
495 
496 	read_lock(&dev_base_lock);
497 	dev = __dev_get_by_name(name);
498 	if (dev)
499 		dev_hold(dev);
500 	read_unlock(&dev_base_lock);
501 	return dev;
502 }
503 
504 /**
505  *	__dev_get_by_index - find a device by its ifindex
506  *	@ifindex: index of device
507  *
508  *	Search for an interface by index. Returns %NULL if the device
509  *	is not found or a pointer to the device. The device has not
510  *	had its reference counter increased so the caller must be careful
511  *	about locking. The caller must hold either the RTNL semaphore
512  *	or @dev_base_lock.
513  */
514 
515 struct net_device *__dev_get_by_index(int ifindex)
516 {
517 	struct hlist_node *p;
518 
519 	hlist_for_each(p, dev_index_hash(ifindex)) {
520 		struct net_device *dev
521 			= hlist_entry(p, struct net_device, index_hlist);
522 		if (dev->ifindex == ifindex)
523 			return dev;
524 	}
525 	return NULL;
526 }
527 
528 
529 /**
530  *	dev_get_by_index - find a device by its ifindex
531  *	@ifindex: index of device
532  *
533  *	Search for an interface by index. Returns NULL if the device
534  *	is not found or a pointer to the device. The device returned has
535  *	had a reference added and the pointer is safe until the user calls
536  *	dev_put to indicate they have finished with it.
537  */
538 
539 struct net_device *dev_get_by_index(int ifindex)
540 {
541 	struct net_device *dev;
542 
543 	read_lock(&dev_base_lock);
544 	dev = __dev_get_by_index(ifindex);
545 	if (dev)
546 		dev_hold(dev);
547 	read_unlock(&dev_base_lock);
548 	return dev;
549 }
550 
551 /**
552  *	dev_getbyhwaddr - find a device by its hardware address
553  *	@type: media type of device
554  *	@ha: hardware address
555  *
556  *	Search for an interface by MAC address. Returns NULL if the device
557  *	is not found or a pointer to the device. The caller must hold the
558  *	rtnl semaphore. The returned device has not had its ref count increased
559  *	and the caller must therefore be careful about locking
560  *
561  *	BUGS:
562  *	If the API was consistent this would be __dev_get_by_hwaddr
563  */
564 
565 struct net_device *dev_getbyhwaddr(unsigned short type, char *ha)
566 {
567 	struct net_device *dev;
568 
569 	ASSERT_RTNL();
570 
571 	for (dev = dev_base; dev; dev = dev->next)
572 		if (dev->type == type &&
573 		    !memcmp(dev->dev_addr, ha, dev->addr_len))
574 			break;
575 	return dev;
576 }
577 
578 EXPORT_SYMBOL(dev_getbyhwaddr);
579 
580 struct net_device *dev_getfirstbyhwtype(unsigned short type)
581 {
582 	struct net_device *dev;
583 
584 	rtnl_lock();
585 	for (dev = dev_base; dev; dev = dev->next) {
586 		if (dev->type == type) {
587 			dev_hold(dev);
588 			break;
589 		}
590 	}
591 	rtnl_unlock();
592 	return dev;
593 }
594 
595 EXPORT_SYMBOL(dev_getfirstbyhwtype);
596 
597 /**
598  *	dev_get_by_flags - find any device with given flags
599  *	@if_flags: IFF_* values
600  *	@mask: bitmask of bits in if_flags to check
601  *
602  *	Search for any interface with the given flags. Returns NULL if a device
603  *	is not found or a pointer to the device. The device returned has
604  *	had a reference added and the pointer is safe until the user calls
605  *	dev_put to indicate they have finished with it.
606  */
607 
608 struct net_device * dev_get_by_flags(unsigned short if_flags, unsigned short mask)
609 {
610 	struct net_device *dev;
611 
612 	read_lock(&dev_base_lock);
613 	for (dev = dev_base; dev != NULL; dev = dev->next) {
614 		if (((dev->flags ^ if_flags) & mask) == 0) {
615 			dev_hold(dev);
616 			break;
617 		}
618 	}
619 	read_unlock(&dev_base_lock);
620 	return dev;
621 }
622 
623 /**
624  *	dev_valid_name - check if name is okay for network device
625  *	@name: name string
626  *
627  *	Network device names need to be valid file names to
628  *	to allow sysfs to work
629  */
630 int dev_valid_name(const char *name)
631 {
632 	return !(*name == '\0'
633 		 || !strcmp(name, ".")
634 		 || !strcmp(name, "..")
635 		 || strchr(name, '/'));
636 }
637 
638 /**
639  *	dev_alloc_name - allocate a name for a device
640  *	@dev: device
641  *	@name: name format string
642  *
643  *	Passed a format string - eg "lt%d" it will try and find a suitable
644  *	id. Not efficient for many devices, not called a lot. The caller
645  *	must hold the dev_base or rtnl lock while allocating the name and
646  *	adding the device in order to avoid duplicates. Returns the number
647  *	of the unit assigned or a negative errno code.
648  */
649 
650 int dev_alloc_name(struct net_device *dev, const char *name)
651 {
652 	int i = 0;
653 	char buf[IFNAMSIZ];
654 	const char *p;
655 	const int max_netdevices = 8*PAGE_SIZE;
656 	long *inuse;
657 	struct net_device *d;
658 
659 	p = strnchr(name, IFNAMSIZ-1, '%');
660 	if (p) {
661 		/*
662 		 * Verify the string as this thing may have come from
663 		 * the user.  There must be either one "%d" and no other "%"
664 		 * characters.
665 		 */
666 		if (p[1] != 'd' || strchr(p + 2, '%'))
667 			return -EINVAL;
668 
669 		/* Use one page as a bit array of possible slots */
670 		inuse = (long *) get_zeroed_page(GFP_ATOMIC);
671 		if (!inuse)
672 			return -ENOMEM;
673 
674 		for (d = dev_base; d; d = d->next) {
675 			if (!sscanf(d->name, name, &i))
676 				continue;
677 			if (i < 0 || i >= max_netdevices)
678 				continue;
679 
680 			/*  avoid cases where sscanf is not exact inverse of printf */
681 			snprintf(buf, sizeof(buf), name, i);
682 			if (!strncmp(buf, d->name, IFNAMSIZ))
683 				set_bit(i, inuse);
684 		}
685 
686 		i = find_first_zero_bit(inuse, max_netdevices);
687 		free_page((unsigned long) inuse);
688 	}
689 
690 	snprintf(buf, sizeof(buf), name, i);
691 	if (!__dev_get_by_name(buf)) {
692 		strlcpy(dev->name, buf, IFNAMSIZ);
693 		return i;
694 	}
695 
696 	/* It is possible to run out of possible slots
697 	 * when the name is long and there isn't enough space left
698 	 * for the digits, or if all bits are used.
699 	 */
700 	return -ENFILE;
701 }
702 
703 
704 /**
705  *	dev_change_name - change name of a device
706  *	@dev: device
707  *	@newname: name (or format string) must be at least IFNAMSIZ
708  *
709  *	Change name of a device, can pass format strings "eth%d".
710  *	for wildcarding.
711  */
712 int dev_change_name(struct net_device *dev, char *newname)
713 {
714 	int err = 0;
715 
716 	ASSERT_RTNL();
717 
718 	if (dev->flags & IFF_UP)
719 		return -EBUSY;
720 
721 	if (!dev_valid_name(newname))
722 		return -EINVAL;
723 
724 	if (strchr(newname, '%')) {
725 		err = dev_alloc_name(dev, newname);
726 		if (err < 0)
727 			return err;
728 		strcpy(newname, dev->name);
729 	}
730 	else if (__dev_get_by_name(newname))
731 		return -EEXIST;
732 	else
733 		strlcpy(dev->name, newname, IFNAMSIZ);
734 
735 	err = class_device_rename(&dev->class_dev, dev->name);
736 	if (!err) {
737 		hlist_del(&dev->name_hlist);
738 		hlist_add_head(&dev->name_hlist, dev_name_hash(dev->name));
739 		blocking_notifier_call_chain(&netdev_chain,
740 				NETDEV_CHANGENAME, dev);
741 	}
742 
743 	return err;
744 }
745 
746 /**
747  *	netdev_features_change - device changes fatures
748  *	@dev: device to cause notification
749  *
750  *	Called to indicate a device has changed features.
751  */
752 void netdev_features_change(struct net_device *dev)
753 {
754 	blocking_notifier_call_chain(&netdev_chain, NETDEV_FEAT_CHANGE, dev);
755 }
756 EXPORT_SYMBOL(netdev_features_change);
757 
758 /**
759  *	netdev_state_change - device changes state
760  *	@dev: device to cause notification
761  *
762  *	Called to indicate a device has changed state. This function calls
763  *	the notifier chains for netdev_chain and sends a NEWLINK message
764  *	to the routing socket.
765  */
766 void netdev_state_change(struct net_device *dev)
767 {
768 	if (dev->flags & IFF_UP) {
769 		blocking_notifier_call_chain(&netdev_chain,
770 				NETDEV_CHANGE, dev);
771 		rtmsg_ifinfo(RTM_NEWLINK, dev, 0);
772 	}
773 }
774 
775 /**
776  *	dev_load 	- load a network module
777  *	@name: name of interface
778  *
779  *	If a network interface is not present and the process has suitable
780  *	privileges this function loads the module. If module loading is not
781  *	available in this kernel then it becomes a nop.
782  */
783 
784 void dev_load(const char *name)
785 {
786 	struct net_device *dev;
787 
788 	read_lock(&dev_base_lock);
789 	dev = __dev_get_by_name(name);
790 	read_unlock(&dev_base_lock);
791 
792 	if (!dev && capable(CAP_SYS_MODULE))
793 		request_module("%s", name);
794 }
795 
796 static int default_rebuild_header(struct sk_buff *skb)
797 {
798 	printk(KERN_DEBUG "%s: default_rebuild_header called -- BUG!\n",
799 	       skb->dev ? skb->dev->name : "NULL!!!");
800 	kfree_skb(skb);
801 	return 1;
802 }
803 
804 
805 /**
806  *	dev_open	- prepare an interface for use.
807  *	@dev:	device to open
808  *
809  *	Takes a device from down to up state. The device's private open
810  *	function is invoked and then the multicast lists are loaded. Finally
811  *	the device is moved into the up state and a %NETDEV_UP message is
812  *	sent to the netdev notifier chain.
813  *
814  *	Calling this function on an active interface is a nop. On a failure
815  *	a negative errno code is returned.
816  */
817 int dev_open(struct net_device *dev)
818 {
819 	int ret = 0;
820 
821 	/*
822 	 *	Is it already up?
823 	 */
824 
825 	if (dev->flags & IFF_UP)
826 		return 0;
827 
828 	/*
829 	 *	Is it even present?
830 	 */
831 	if (!netif_device_present(dev))
832 		return -ENODEV;
833 
834 	/*
835 	 *	Call device private open method
836 	 */
837 	set_bit(__LINK_STATE_START, &dev->state);
838 	if (dev->open) {
839 		ret = dev->open(dev);
840 		if (ret)
841 			clear_bit(__LINK_STATE_START, &dev->state);
842 	}
843 
844  	/*
845 	 *	If it went open OK then:
846 	 */
847 
848 	if (!ret) {
849 		/*
850 		 *	Set the flags.
851 		 */
852 		dev->flags |= IFF_UP;
853 
854 		/*
855 		 *	Initialize multicasting status
856 		 */
857 		dev_mc_upload(dev);
858 
859 		/*
860 		 *	Wakeup transmit queue engine
861 		 */
862 		dev_activate(dev);
863 
864 		/*
865 		 *	... and announce new interface.
866 		 */
867 		blocking_notifier_call_chain(&netdev_chain, NETDEV_UP, dev);
868 	}
869 	return ret;
870 }
871 
872 /**
873  *	dev_close - shutdown an interface.
874  *	@dev: device to shutdown
875  *
876  *	This function moves an active device into down state. A
877  *	%NETDEV_GOING_DOWN is sent to the netdev notifier chain. The device
878  *	is then deactivated and finally a %NETDEV_DOWN is sent to the notifier
879  *	chain.
880  */
881 int dev_close(struct net_device *dev)
882 {
883 	if (!(dev->flags & IFF_UP))
884 		return 0;
885 
886 	/*
887 	 *	Tell people we are going down, so that they can
888 	 *	prepare to death, when device is still operating.
889 	 */
890 	blocking_notifier_call_chain(&netdev_chain, NETDEV_GOING_DOWN, dev);
891 
892 	dev_deactivate(dev);
893 
894 	clear_bit(__LINK_STATE_START, &dev->state);
895 
896 	/* Synchronize to scheduled poll. We cannot touch poll list,
897 	 * it can be even on different cpu. So just clear netif_running(),
898 	 * and wait when poll really will happen. Actually, the best place
899 	 * for this is inside dev->stop() after device stopped its irq
900 	 * engine, but this requires more changes in devices. */
901 
902 	smp_mb__after_clear_bit(); /* Commit netif_running(). */
903 	while (test_bit(__LINK_STATE_RX_SCHED, &dev->state)) {
904 		/* No hurry. */
905 		msleep(1);
906 	}
907 
908 	/*
909 	 *	Call the device specific close. This cannot fail.
910 	 *	Only if device is UP
911 	 *
912 	 *	We allow it to be called even after a DETACH hot-plug
913 	 *	event.
914 	 */
915 	if (dev->stop)
916 		dev->stop(dev);
917 
918 	/*
919 	 *	Device is now down.
920 	 */
921 
922 	dev->flags &= ~IFF_UP;
923 
924 	/*
925 	 * Tell people we are down
926 	 */
927 	blocking_notifier_call_chain(&netdev_chain, NETDEV_DOWN, dev);
928 
929 	return 0;
930 }
931 
932 
933 /*
934  *	Device change register/unregister. These are not inline or static
935  *	as we export them to the world.
936  */
937 
938 /**
939  *	register_netdevice_notifier - register a network notifier block
940  *	@nb: notifier
941  *
942  *	Register a notifier to be called when network device events occur.
943  *	The notifier passed is linked into the kernel structures and must
944  *	not be reused until it has been unregistered. A negative errno code
945  *	is returned on a failure.
946  *
947  * 	When registered all registration and up events are replayed
948  *	to the new notifier to allow device to have a race free
949  *	view of the network device list.
950  */
951 
952 int register_netdevice_notifier(struct notifier_block *nb)
953 {
954 	struct net_device *dev;
955 	int err;
956 
957 	rtnl_lock();
958 	err = blocking_notifier_chain_register(&netdev_chain, nb);
959 	if (!err) {
960 		for (dev = dev_base; dev; dev = dev->next) {
961 			nb->notifier_call(nb, NETDEV_REGISTER, dev);
962 
963 			if (dev->flags & IFF_UP)
964 				nb->notifier_call(nb, NETDEV_UP, dev);
965 		}
966 	}
967 	rtnl_unlock();
968 	return err;
969 }
970 
971 /**
972  *	unregister_netdevice_notifier - unregister a network notifier block
973  *	@nb: notifier
974  *
975  *	Unregister a notifier previously registered by
976  *	register_netdevice_notifier(). The notifier is unlinked into the
977  *	kernel structures and may then be reused. A negative errno code
978  *	is returned on a failure.
979  */
980 
981 int unregister_netdevice_notifier(struct notifier_block *nb)
982 {
983 	int err;
984 
985 	rtnl_lock();
986 	err = blocking_notifier_chain_unregister(&netdev_chain, nb);
987 	rtnl_unlock();
988 	return err;
989 }
990 
991 /**
992  *	call_netdevice_notifiers - call all network notifier blocks
993  *      @val: value passed unmodified to notifier function
994  *      @v:   pointer passed unmodified to notifier function
995  *
996  *	Call all network notifier blocks.  Parameters and return value
997  *	are as for blocking_notifier_call_chain().
998  */
999 
1000 int call_netdevice_notifiers(unsigned long val, void *v)
1001 {
1002 	return blocking_notifier_call_chain(&netdev_chain, val, v);
1003 }
1004 
1005 /* When > 0 there are consumers of rx skb time stamps */
1006 static atomic_t netstamp_needed = ATOMIC_INIT(0);
1007 
1008 void net_enable_timestamp(void)
1009 {
1010 	atomic_inc(&netstamp_needed);
1011 }
1012 
1013 void net_disable_timestamp(void)
1014 {
1015 	atomic_dec(&netstamp_needed);
1016 }
1017 
1018 void __net_timestamp(struct sk_buff *skb)
1019 {
1020 	struct timeval tv;
1021 
1022 	do_gettimeofday(&tv);
1023 	skb_set_timestamp(skb, &tv);
1024 }
1025 EXPORT_SYMBOL(__net_timestamp);
1026 
1027 static inline void net_timestamp(struct sk_buff *skb)
1028 {
1029 	if (atomic_read(&netstamp_needed))
1030 		__net_timestamp(skb);
1031 	else {
1032 		skb->tstamp.off_sec = 0;
1033 		skb->tstamp.off_usec = 0;
1034 	}
1035 }
1036 
1037 /*
1038  *	Support routine. Sends outgoing frames to any network
1039  *	taps currently in use.
1040  */
1041 
1042 void dev_queue_xmit_nit(struct sk_buff *skb, struct net_device *dev)
1043 {
1044 	struct packet_type *ptype;
1045 
1046 	net_timestamp(skb);
1047 
1048 	rcu_read_lock();
1049 	list_for_each_entry_rcu(ptype, &ptype_all, list) {
1050 		/* Never send packets back to the socket
1051 		 * they originated from - MvS (miquels@drinkel.ow.org)
1052 		 */
1053 		if ((ptype->dev == dev || !ptype->dev) &&
1054 		    (ptype->af_packet_priv == NULL ||
1055 		     (struct sock *)ptype->af_packet_priv != skb->sk)) {
1056 			struct sk_buff *skb2= skb_clone(skb, GFP_ATOMIC);
1057 			if (!skb2)
1058 				break;
1059 
1060 			/* skb->nh should be correctly
1061 			   set by sender, so that the second statement is
1062 			   just protection against buggy protocols.
1063 			 */
1064 			skb2->mac.raw = skb2->data;
1065 
1066 			if (skb2->nh.raw < skb2->data ||
1067 			    skb2->nh.raw > skb2->tail) {
1068 				if (net_ratelimit())
1069 					printk(KERN_CRIT "protocol %04x is "
1070 					       "buggy, dev %s\n",
1071 					       skb2->protocol, dev->name);
1072 				skb2->nh.raw = skb2->data;
1073 			}
1074 
1075 			skb2->h.raw = skb2->nh.raw;
1076 			skb2->pkt_type = PACKET_OUTGOING;
1077 			ptype->func(skb2, skb->dev, ptype, skb->dev);
1078 		}
1079 	}
1080 	rcu_read_unlock();
1081 }
1082 
1083 /*
1084  * Invalidate hardware checksum when packet is to be mangled, and
1085  * complete checksum manually on outgoing path.
1086  */
1087 int skb_checksum_help(struct sk_buff *skb, int inward)
1088 {
1089 	unsigned int csum;
1090 	int ret = 0, offset = skb->h.raw - skb->data;
1091 
1092 	if (inward) {
1093 		skb->ip_summed = CHECKSUM_NONE;
1094 		goto out;
1095 	}
1096 
1097 	if (skb_cloned(skb)) {
1098 		ret = pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
1099 		if (ret)
1100 			goto out;
1101 	}
1102 
1103 	BUG_ON(offset > (int)skb->len);
1104 	csum = skb_checksum(skb, offset, skb->len-offset, 0);
1105 
1106 	offset = skb->tail - skb->h.raw;
1107 	BUG_ON(offset <= 0);
1108 	BUG_ON(skb->csum + 2 > offset);
1109 
1110 	*(u16*)(skb->h.raw + skb->csum) = csum_fold(csum);
1111 	skb->ip_summed = CHECKSUM_NONE;
1112 out:
1113 	return ret;
1114 }
1115 
1116 /* Take action when hardware reception checksum errors are detected. */
1117 #ifdef CONFIG_BUG
1118 void netdev_rx_csum_fault(struct net_device *dev)
1119 {
1120 	if (net_ratelimit()) {
1121 		printk(KERN_ERR "%s: hw csum failure.\n",
1122 			dev ? dev->name : "<unknown>");
1123 		dump_stack();
1124 	}
1125 }
1126 EXPORT_SYMBOL(netdev_rx_csum_fault);
1127 #endif
1128 
1129 #ifdef CONFIG_HIGHMEM
1130 /* Actually, we should eliminate this check as soon as we know, that:
1131  * 1. IOMMU is present and allows to map all the memory.
1132  * 2. No high memory really exists on this machine.
1133  */
1134 
1135 static inline int illegal_highdma(struct net_device *dev, struct sk_buff *skb)
1136 {
1137 	int i;
1138 
1139 	if (dev->features & NETIF_F_HIGHDMA)
1140 		return 0;
1141 
1142 	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
1143 		if (PageHighMem(skb_shinfo(skb)->frags[i].page))
1144 			return 1;
1145 
1146 	return 0;
1147 }
1148 #else
1149 #define illegal_highdma(dev, skb)	(0)
1150 #endif
1151 
1152 /* Keep head the same: replace data */
1153 int __skb_linearize(struct sk_buff *skb, gfp_t gfp_mask)
1154 {
1155 	unsigned int size;
1156 	u8 *data;
1157 	long offset;
1158 	struct skb_shared_info *ninfo;
1159 	int headerlen = skb->data - skb->head;
1160 	int expand = (skb->tail + skb->data_len) - skb->end;
1161 
1162 	if (skb_shared(skb))
1163 		BUG();
1164 
1165 	if (expand <= 0)
1166 		expand = 0;
1167 
1168 	size = skb->end - skb->head + expand;
1169 	size = SKB_DATA_ALIGN(size);
1170 	data = kmalloc(size + sizeof(struct skb_shared_info), gfp_mask);
1171 	if (!data)
1172 		return -ENOMEM;
1173 
1174 	/* Copy entire thing */
1175 	if (skb_copy_bits(skb, -headerlen, data, headerlen + skb->len))
1176 		BUG();
1177 
1178 	/* Set up shinfo */
1179 	ninfo = (struct skb_shared_info*)(data + size);
1180 	atomic_set(&ninfo->dataref, 1);
1181 	ninfo->tso_size = skb_shinfo(skb)->tso_size;
1182 	ninfo->tso_segs = skb_shinfo(skb)->tso_segs;
1183 	ninfo->nr_frags = 0;
1184 	ninfo->frag_list = NULL;
1185 
1186 	/* Offset between the two in bytes */
1187 	offset = data - skb->head;
1188 
1189 	/* Free old data. */
1190 	skb_release_data(skb);
1191 
1192 	skb->head = data;
1193 	skb->end  = data + size;
1194 
1195 	/* Set up new pointers */
1196 	skb->h.raw   += offset;
1197 	skb->nh.raw  += offset;
1198 	skb->mac.raw += offset;
1199 	skb->tail    += offset;
1200 	skb->data    += offset;
1201 
1202 	/* We are no longer a clone, even if we were. */
1203 	skb->cloned    = 0;
1204 
1205 	skb->tail     += skb->data_len;
1206 	skb->data_len  = 0;
1207 	return 0;
1208 }
1209 
1210 #define HARD_TX_LOCK(dev, cpu) {			\
1211 	if ((dev->features & NETIF_F_LLTX) == 0) {	\
1212 		spin_lock(&dev->xmit_lock);		\
1213 		dev->xmit_lock_owner = cpu;		\
1214 	}						\
1215 }
1216 
1217 #define HARD_TX_UNLOCK(dev) {				\
1218 	if ((dev->features & NETIF_F_LLTX) == 0) {	\
1219 		dev->xmit_lock_owner = -1;		\
1220 		spin_unlock(&dev->xmit_lock);		\
1221 	}						\
1222 }
1223 
1224 /**
1225  *	dev_queue_xmit - transmit a buffer
1226  *	@skb: buffer to transmit
1227  *
1228  *	Queue a buffer for transmission to a network device. The caller must
1229  *	have set the device and priority and built the buffer before calling
1230  *	this function. The function can be called from an interrupt.
1231  *
1232  *	A negative errno code is returned on a failure. A success does not
1233  *	guarantee the frame will be transmitted as it may be dropped due
1234  *	to congestion or traffic shaping.
1235  *
1236  * -----------------------------------------------------------------------------------
1237  *      I notice this method can also return errors from the queue disciplines,
1238  *      including NET_XMIT_DROP, which is a positive value.  So, errors can also
1239  *      be positive.
1240  *
1241  *      Regardless of the return value, the skb is consumed, so it is currently
1242  *      difficult to retry a send to this method.  (You can bump the ref count
1243  *      before sending to hold a reference for retry if you are careful.)
1244  *
1245  *      When calling this method, interrupts MUST be enabled.  This is because
1246  *      the BH enable code must have IRQs enabled so that it will not deadlock.
1247  *          --BLG
1248  */
1249 
1250 int dev_queue_xmit(struct sk_buff *skb)
1251 {
1252 	struct net_device *dev = skb->dev;
1253 	struct Qdisc *q;
1254 	int rc = -ENOMEM;
1255 
1256 	if (skb_shinfo(skb)->frag_list &&
1257 	    !(dev->features & NETIF_F_FRAGLIST) &&
1258 	    __skb_linearize(skb, GFP_ATOMIC))
1259 		goto out_kfree_skb;
1260 
1261 	/* Fragmented skb is linearized if device does not support SG,
1262 	 * or if at least one of fragments is in highmem and device
1263 	 * does not support DMA from it.
1264 	 */
1265 	if (skb_shinfo(skb)->nr_frags &&
1266 	    (!(dev->features & NETIF_F_SG) || illegal_highdma(dev, skb)) &&
1267 	    __skb_linearize(skb, GFP_ATOMIC))
1268 		goto out_kfree_skb;
1269 
1270 	/* If packet is not checksummed and device does not support
1271 	 * checksumming for this protocol, complete checksumming here.
1272 	 */
1273 	if (skb->ip_summed == CHECKSUM_HW &&
1274 	    (!(dev->features & (NETIF_F_HW_CSUM | NETIF_F_NO_CSUM)) &&
1275 	     (!(dev->features & NETIF_F_IP_CSUM) ||
1276 	      skb->protocol != htons(ETH_P_IP))))
1277 	      	if (skb_checksum_help(skb, 0))
1278 	      		goto out_kfree_skb;
1279 
1280 	spin_lock_prefetch(&dev->queue_lock);
1281 
1282 	/* Disable soft irqs for various locks below. Also
1283 	 * stops preemption for RCU.
1284 	 */
1285 	local_bh_disable();
1286 
1287 	/* Updates of qdisc are serialized by queue_lock.
1288 	 * The struct Qdisc which is pointed to by qdisc is now a
1289 	 * rcu structure - it may be accessed without acquiring
1290 	 * a lock (but the structure may be stale.) The freeing of the
1291 	 * qdisc will be deferred until it's known that there are no
1292 	 * more references to it.
1293 	 *
1294 	 * If the qdisc has an enqueue function, we still need to
1295 	 * hold the queue_lock before calling it, since queue_lock
1296 	 * also serializes access to the device queue.
1297 	 */
1298 
1299 	q = rcu_dereference(dev->qdisc);
1300 #ifdef CONFIG_NET_CLS_ACT
1301 	skb->tc_verd = SET_TC_AT(skb->tc_verd,AT_EGRESS);
1302 #endif
1303 	if (q->enqueue) {
1304 		/* Grab device queue */
1305 		spin_lock(&dev->queue_lock);
1306 
1307 		rc = q->enqueue(skb, q);
1308 
1309 		qdisc_run(dev);
1310 
1311 		spin_unlock(&dev->queue_lock);
1312 		rc = rc == NET_XMIT_BYPASS ? NET_XMIT_SUCCESS : rc;
1313 		goto out;
1314 	}
1315 
1316 	/* The device has no queue. Common case for software devices:
1317 	   loopback, all the sorts of tunnels...
1318 
1319 	   Really, it is unlikely that xmit_lock protection is necessary here.
1320 	   (f.e. loopback and IP tunnels are clean ignoring statistics
1321 	   counters.)
1322 	   However, it is possible, that they rely on protection
1323 	   made by us here.
1324 
1325 	   Check this and shot the lock. It is not prone from deadlocks.
1326 	   Either shot noqueue qdisc, it is even simpler 8)
1327 	 */
1328 	if (dev->flags & IFF_UP) {
1329 		int cpu = smp_processor_id(); /* ok because BHs are off */
1330 
1331 		if (dev->xmit_lock_owner != cpu) {
1332 
1333 			HARD_TX_LOCK(dev, cpu);
1334 
1335 			if (!netif_queue_stopped(dev)) {
1336 				if (netdev_nit)
1337 					dev_queue_xmit_nit(skb, dev);
1338 
1339 				rc = 0;
1340 				if (!dev->hard_start_xmit(skb, dev)) {
1341 					HARD_TX_UNLOCK(dev);
1342 					goto out;
1343 				}
1344 			}
1345 			HARD_TX_UNLOCK(dev);
1346 			if (net_ratelimit())
1347 				printk(KERN_CRIT "Virtual device %s asks to "
1348 				       "queue packet!\n", dev->name);
1349 		} else {
1350 			/* Recursion is detected! It is possible,
1351 			 * unfortunately */
1352 			if (net_ratelimit())
1353 				printk(KERN_CRIT "Dead loop on virtual device "
1354 				       "%s, fix it urgently!\n", dev->name);
1355 		}
1356 	}
1357 
1358 	rc = -ENETDOWN;
1359 	local_bh_enable();
1360 
1361 out_kfree_skb:
1362 	kfree_skb(skb);
1363 	return rc;
1364 out:
1365 	local_bh_enable();
1366 	return rc;
1367 }
1368 
1369 
1370 /*=======================================================================
1371 			Receiver routines
1372   =======================================================================*/
1373 
1374 int netdev_max_backlog = 1000;
1375 int netdev_budget = 300;
1376 int weight_p = 64;            /* old backlog weight */
1377 
1378 DEFINE_PER_CPU(struct netif_rx_stats, netdev_rx_stat) = { 0, };
1379 
1380 
1381 /**
1382  *	netif_rx	-	post buffer to the network code
1383  *	@skb: buffer to post
1384  *
1385  *	This function receives a packet from a device driver and queues it for
1386  *	the upper (protocol) levels to process.  It always succeeds. The buffer
1387  *	may be dropped during processing for congestion control or by the
1388  *	protocol layers.
1389  *
1390  *	return values:
1391  *	NET_RX_SUCCESS	(no congestion)
1392  *	NET_RX_CN_LOW   (low congestion)
1393  *	NET_RX_CN_MOD   (moderate congestion)
1394  *	NET_RX_CN_HIGH  (high congestion)
1395  *	NET_RX_DROP     (packet was dropped)
1396  *
1397  */
1398 
1399 int netif_rx(struct sk_buff *skb)
1400 {
1401 	struct softnet_data *queue;
1402 	unsigned long flags;
1403 
1404 	/* if netpoll wants it, pretend we never saw it */
1405 	if (netpoll_rx(skb))
1406 		return NET_RX_DROP;
1407 
1408 	if (!skb->tstamp.off_sec)
1409 		net_timestamp(skb);
1410 
1411 	/*
1412 	 * The code is rearranged so that the path is the most
1413 	 * short when CPU is congested, but is still operating.
1414 	 */
1415 	local_irq_save(flags);
1416 	queue = &__get_cpu_var(softnet_data);
1417 
1418 	__get_cpu_var(netdev_rx_stat).total++;
1419 	if (queue->input_pkt_queue.qlen <= netdev_max_backlog) {
1420 		if (queue->input_pkt_queue.qlen) {
1421 enqueue:
1422 			dev_hold(skb->dev);
1423 			__skb_queue_tail(&queue->input_pkt_queue, skb);
1424 			local_irq_restore(flags);
1425 			return NET_RX_SUCCESS;
1426 		}
1427 
1428 		netif_rx_schedule(&queue->backlog_dev);
1429 		goto enqueue;
1430 	}
1431 
1432 	__get_cpu_var(netdev_rx_stat).dropped++;
1433 	local_irq_restore(flags);
1434 
1435 	kfree_skb(skb);
1436 	return NET_RX_DROP;
1437 }
1438 
1439 int netif_rx_ni(struct sk_buff *skb)
1440 {
1441 	int err;
1442 
1443 	preempt_disable();
1444 	err = netif_rx(skb);
1445 	if (local_softirq_pending())
1446 		do_softirq();
1447 	preempt_enable();
1448 
1449 	return err;
1450 }
1451 
1452 EXPORT_SYMBOL(netif_rx_ni);
1453 
1454 static inline struct net_device *skb_bond(struct sk_buff *skb)
1455 {
1456 	struct net_device *dev = skb->dev;
1457 
1458 	if (dev->master) {
1459 		/*
1460 		 * On bonding slaves other than the currently active
1461 		 * slave, suppress duplicates except for 802.3ad
1462 		 * ETH_P_SLOW and alb non-mcast/bcast.
1463 		 */
1464 		if (dev->priv_flags & IFF_SLAVE_INACTIVE) {
1465 			if (dev->master->priv_flags & IFF_MASTER_ALB) {
1466 				if (skb->pkt_type != PACKET_BROADCAST &&
1467 				    skb->pkt_type != PACKET_MULTICAST)
1468 					goto keep;
1469 			}
1470 
1471 			if (dev->master->priv_flags & IFF_MASTER_8023AD &&
1472 			    skb->protocol == __constant_htons(ETH_P_SLOW))
1473 				goto keep;
1474 
1475 			kfree_skb(skb);
1476 			return NULL;
1477 		}
1478 keep:
1479 		skb->dev = dev->master;
1480 	}
1481 
1482 	return dev;
1483 }
1484 
1485 static void net_tx_action(struct softirq_action *h)
1486 {
1487 	struct softnet_data *sd = &__get_cpu_var(softnet_data);
1488 
1489 	if (sd->completion_queue) {
1490 		struct sk_buff *clist;
1491 
1492 		local_irq_disable();
1493 		clist = sd->completion_queue;
1494 		sd->completion_queue = NULL;
1495 		local_irq_enable();
1496 
1497 		while (clist) {
1498 			struct sk_buff *skb = clist;
1499 			clist = clist->next;
1500 
1501 			BUG_TRAP(!atomic_read(&skb->users));
1502 			__kfree_skb(skb);
1503 		}
1504 	}
1505 
1506 	if (sd->output_queue) {
1507 		struct net_device *head;
1508 
1509 		local_irq_disable();
1510 		head = sd->output_queue;
1511 		sd->output_queue = NULL;
1512 		local_irq_enable();
1513 
1514 		while (head) {
1515 			struct net_device *dev = head;
1516 			head = head->next_sched;
1517 
1518 			smp_mb__before_clear_bit();
1519 			clear_bit(__LINK_STATE_SCHED, &dev->state);
1520 
1521 			if (spin_trylock(&dev->queue_lock)) {
1522 				qdisc_run(dev);
1523 				spin_unlock(&dev->queue_lock);
1524 			} else {
1525 				netif_schedule(dev);
1526 			}
1527 		}
1528 	}
1529 }
1530 
1531 static __inline__ int deliver_skb(struct sk_buff *skb,
1532 				  struct packet_type *pt_prev,
1533 				  struct net_device *orig_dev)
1534 {
1535 	atomic_inc(&skb->users);
1536 	return pt_prev->func(skb, skb->dev, pt_prev, orig_dev);
1537 }
1538 
1539 #if defined(CONFIG_BRIDGE) || defined (CONFIG_BRIDGE_MODULE)
1540 int (*br_handle_frame_hook)(struct net_bridge_port *p, struct sk_buff **pskb);
1541 struct net_bridge;
1542 struct net_bridge_fdb_entry *(*br_fdb_get_hook)(struct net_bridge *br,
1543 						unsigned char *addr);
1544 void (*br_fdb_put_hook)(struct net_bridge_fdb_entry *ent);
1545 
1546 static __inline__ int handle_bridge(struct sk_buff **pskb,
1547 				    struct packet_type **pt_prev, int *ret,
1548 				    struct net_device *orig_dev)
1549 {
1550 	struct net_bridge_port *port;
1551 
1552 	if ((*pskb)->pkt_type == PACKET_LOOPBACK ||
1553 	    (port = rcu_dereference((*pskb)->dev->br_port)) == NULL)
1554 		return 0;
1555 
1556 	if (*pt_prev) {
1557 		*ret = deliver_skb(*pskb, *pt_prev, orig_dev);
1558 		*pt_prev = NULL;
1559 	}
1560 
1561 	return br_handle_frame_hook(port, pskb);
1562 }
1563 #else
1564 #define handle_bridge(skb, pt_prev, ret, orig_dev)	(0)
1565 #endif
1566 
1567 #ifdef CONFIG_NET_CLS_ACT
1568 /* TODO: Maybe we should just force sch_ingress to be compiled in
1569  * when CONFIG_NET_CLS_ACT is? otherwise some useless instructions
1570  * a compare and 2 stores extra right now if we dont have it on
1571  * but have CONFIG_NET_CLS_ACT
1572  * NOTE: This doesnt stop any functionality; if you dont have
1573  * the ingress scheduler, you just cant add policies on ingress.
1574  *
1575  */
1576 static int ing_filter(struct sk_buff *skb)
1577 {
1578 	struct Qdisc *q;
1579 	struct net_device *dev = skb->dev;
1580 	int result = TC_ACT_OK;
1581 
1582 	if (dev->qdisc_ingress) {
1583 		__u32 ttl = (__u32) G_TC_RTTL(skb->tc_verd);
1584 		if (MAX_RED_LOOP < ttl++) {
1585 			printk("Redir loop detected Dropping packet (%s->%s)\n",
1586 				skb->input_dev->name, skb->dev->name);
1587 			return TC_ACT_SHOT;
1588 		}
1589 
1590 		skb->tc_verd = SET_TC_RTTL(skb->tc_verd,ttl);
1591 
1592 		skb->tc_verd = SET_TC_AT(skb->tc_verd,AT_INGRESS);
1593 
1594 		spin_lock(&dev->ingress_lock);
1595 		if ((q = dev->qdisc_ingress) != NULL)
1596 			result = q->enqueue(skb, q);
1597 		spin_unlock(&dev->ingress_lock);
1598 
1599 	}
1600 
1601 	return result;
1602 }
1603 #endif
1604 
1605 int netif_receive_skb(struct sk_buff *skb)
1606 {
1607 	struct packet_type *ptype, *pt_prev;
1608 	struct net_device *orig_dev;
1609 	int ret = NET_RX_DROP;
1610 	unsigned short type;
1611 
1612 	/* if we've gotten here through NAPI, check netpoll */
1613 	if (skb->dev->poll && netpoll_rx(skb))
1614 		return NET_RX_DROP;
1615 
1616 	if (!skb->tstamp.off_sec)
1617 		net_timestamp(skb);
1618 
1619 	if (!skb->input_dev)
1620 		skb->input_dev = skb->dev;
1621 
1622 	orig_dev = skb_bond(skb);
1623 
1624 	if (!orig_dev)
1625 		return NET_RX_DROP;
1626 
1627 	__get_cpu_var(netdev_rx_stat).total++;
1628 
1629 	skb->h.raw = skb->nh.raw = skb->data;
1630 	skb->mac_len = skb->nh.raw - skb->mac.raw;
1631 
1632 	pt_prev = NULL;
1633 
1634 	rcu_read_lock();
1635 
1636 #ifdef CONFIG_NET_CLS_ACT
1637 	if (skb->tc_verd & TC_NCLS) {
1638 		skb->tc_verd = CLR_TC_NCLS(skb->tc_verd);
1639 		goto ncls;
1640 	}
1641 #endif
1642 
1643 	list_for_each_entry_rcu(ptype, &ptype_all, list) {
1644 		if (!ptype->dev || ptype->dev == skb->dev) {
1645 			if (pt_prev)
1646 				ret = deliver_skb(skb, pt_prev, orig_dev);
1647 			pt_prev = ptype;
1648 		}
1649 	}
1650 
1651 #ifdef CONFIG_NET_CLS_ACT
1652 	if (pt_prev) {
1653 		ret = deliver_skb(skb, pt_prev, orig_dev);
1654 		pt_prev = NULL; /* noone else should process this after*/
1655 	} else {
1656 		skb->tc_verd = SET_TC_OK2MUNGE(skb->tc_verd);
1657 	}
1658 
1659 	ret = ing_filter(skb);
1660 
1661 	if (ret == TC_ACT_SHOT || (ret == TC_ACT_STOLEN)) {
1662 		kfree_skb(skb);
1663 		goto out;
1664 	}
1665 
1666 	skb->tc_verd = 0;
1667 ncls:
1668 #endif
1669 
1670 	handle_diverter(skb);
1671 
1672 	if (handle_bridge(&skb, &pt_prev, &ret, orig_dev))
1673 		goto out;
1674 
1675 	type = skb->protocol;
1676 	list_for_each_entry_rcu(ptype, &ptype_base[ntohs(type)&15], list) {
1677 		if (ptype->type == type &&
1678 		    (!ptype->dev || ptype->dev == skb->dev)) {
1679 			if (pt_prev)
1680 				ret = deliver_skb(skb, pt_prev, orig_dev);
1681 			pt_prev = ptype;
1682 		}
1683 	}
1684 
1685 	if (pt_prev) {
1686 		ret = pt_prev->func(skb, skb->dev, pt_prev, orig_dev);
1687 	} else {
1688 		kfree_skb(skb);
1689 		/* Jamal, now you will not able to escape explaining
1690 		 * me how you were going to use this. :-)
1691 		 */
1692 		ret = NET_RX_DROP;
1693 	}
1694 
1695 out:
1696 	rcu_read_unlock();
1697 	return ret;
1698 }
1699 
1700 static int process_backlog(struct net_device *backlog_dev, int *budget)
1701 {
1702 	int work = 0;
1703 	int quota = min(backlog_dev->quota, *budget);
1704 	struct softnet_data *queue = &__get_cpu_var(softnet_data);
1705 	unsigned long start_time = jiffies;
1706 
1707 	backlog_dev->weight = weight_p;
1708 	for (;;) {
1709 		struct sk_buff *skb;
1710 		struct net_device *dev;
1711 
1712 		local_irq_disable();
1713 		skb = __skb_dequeue(&queue->input_pkt_queue);
1714 		if (!skb)
1715 			goto job_done;
1716 		local_irq_enable();
1717 
1718 		dev = skb->dev;
1719 
1720 		netif_receive_skb(skb);
1721 
1722 		dev_put(dev);
1723 
1724 		work++;
1725 
1726 		if (work >= quota || jiffies - start_time > 1)
1727 			break;
1728 
1729 	}
1730 
1731 	backlog_dev->quota -= work;
1732 	*budget -= work;
1733 	return -1;
1734 
1735 job_done:
1736 	backlog_dev->quota -= work;
1737 	*budget -= work;
1738 
1739 	list_del(&backlog_dev->poll_list);
1740 	smp_mb__before_clear_bit();
1741 	netif_poll_enable(backlog_dev);
1742 
1743 	local_irq_enable();
1744 	return 0;
1745 }
1746 
1747 static void net_rx_action(struct softirq_action *h)
1748 {
1749 	struct softnet_data *queue = &__get_cpu_var(softnet_data);
1750 	unsigned long start_time = jiffies;
1751 	int budget = netdev_budget;
1752 	void *have;
1753 
1754 	local_irq_disable();
1755 
1756 	while (!list_empty(&queue->poll_list)) {
1757 		struct net_device *dev;
1758 
1759 		if (budget <= 0 || jiffies - start_time > 1)
1760 			goto softnet_break;
1761 
1762 		local_irq_enable();
1763 
1764 		dev = list_entry(queue->poll_list.next,
1765 				 struct net_device, poll_list);
1766 		have = netpoll_poll_lock(dev);
1767 
1768 		if (dev->quota <= 0 || dev->poll(dev, &budget)) {
1769 			netpoll_poll_unlock(have);
1770 			local_irq_disable();
1771 			list_move_tail(&dev->poll_list, &queue->poll_list);
1772 			if (dev->quota < 0)
1773 				dev->quota += dev->weight;
1774 			else
1775 				dev->quota = dev->weight;
1776 		} else {
1777 			netpoll_poll_unlock(have);
1778 			dev_put(dev);
1779 			local_irq_disable();
1780 		}
1781 	}
1782 out:
1783 	local_irq_enable();
1784 	return;
1785 
1786 softnet_break:
1787 	__get_cpu_var(netdev_rx_stat).time_squeeze++;
1788 	__raise_softirq_irqoff(NET_RX_SOFTIRQ);
1789 	goto out;
1790 }
1791 
1792 static gifconf_func_t * gifconf_list [NPROTO];
1793 
1794 /**
1795  *	register_gifconf	-	register a SIOCGIF handler
1796  *	@family: Address family
1797  *	@gifconf: Function handler
1798  *
1799  *	Register protocol dependent address dumping routines. The handler
1800  *	that is passed must not be freed or reused until it has been replaced
1801  *	by another handler.
1802  */
1803 int register_gifconf(unsigned int family, gifconf_func_t * gifconf)
1804 {
1805 	if (family >= NPROTO)
1806 		return -EINVAL;
1807 	gifconf_list[family] = gifconf;
1808 	return 0;
1809 }
1810 
1811 
1812 /*
1813  *	Map an interface index to its name (SIOCGIFNAME)
1814  */
1815 
1816 /*
1817  *	We need this ioctl for efficient implementation of the
1818  *	if_indextoname() function required by the IPv6 API.  Without
1819  *	it, we would have to search all the interfaces to find a
1820  *	match.  --pb
1821  */
1822 
1823 static int dev_ifname(struct ifreq __user *arg)
1824 {
1825 	struct net_device *dev;
1826 	struct ifreq ifr;
1827 
1828 	/*
1829 	 *	Fetch the caller's info block.
1830 	 */
1831 
1832 	if (copy_from_user(&ifr, arg, sizeof(struct ifreq)))
1833 		return -EFAULT;
1834 
1835 	read_lock(&dev_base_lock);
1836 	dev = __dev_get_by_index(ifr.ifr_ifindex);
1837 	if (!dev) {
1838 		read_unlock(&dev_base_lock);
1839 		return -ENODEV;
1840 	}
1841 
1842 	strcpy(ifr.ifr_name, dev->name);
1843 	read_unlock(&dev_base_lock);
1844 
1845 	if (copy_to_user(arg, &ifr, sizeof(struct ifreq)))
1846 		return -EFAULT;
1847 	return 0;
1848 }
1849 
1850 /*
1851  *	Perform a SIOCGIFCONF call. This structure will change
1852  *	size eventually, and there is nothing I can do about it.
1853  *	Thus we will need a 'compatibility mode'.
1854  */
1855 
1856 static int dev_ifconf(char __user *arg)
1857 {
1858 	struct ifconf ifc;
1859 	struct net_device *dev;
1860 	char __user *pos;
1861 	int len;
1862 	int total;
1863 	int i;
1864 
1865 	/*
1866 	 *	Fetch the caller's info block.
1867 	 */
1868 
1869 	if (copy_from_user(&ifc, arg, sizeof(struct ifconf)))
1870 		return -EFAULT;
1871 
1872 	pos = ifc.ifc_buf;
1873 	len = ifc.ifc_len;
1874 
1875 	/*
1876 	 *	Loop over the interfaces, and write an info block for each.
1877 	 */
1878 
1879 	total = 0;
1880 	for (dev = dev_base; dev; dev = dev->next) {
1881 		for (i = 0; i < NPROTO; i++) {
1882 			if (gifconf_list[i]) {
1883 				int done;
1884 				if (!pos)
1885 					done = gifconf_list[i](dev, NULL, 0);
1886 				else
1887 					done = gifconf_list[i](dev, pos + total,
1888 							       len - total);
1889 				if (done < 0)
1890 					return -EFAULT;
1891 				total += done;
1892 			}
1893 		}
1894   	}
1895 
1896 	/*
1897 	 *	All done.  Write the updated control block back to the caller.
1898 	 */
1899 	ifc.ifc_len = total;
1900 
1901 	/*
1902 	 * 	Both BSD and Solaris return 0 here, so we do too.
1903 	 */
1904 	return copy_to_user(arg, &ifc, sizeof(struct ifconf)) ? -EFAULT : 0;
1905 }
1906 
1907 #ifdef CONFIG_PROC_FS
1908 /*
1909  *	This is invoked by the /proc filesystem handler to display a device
1910  *	in detail.
1911  */
1912 static __inline__ struct net_device *dev_get_idx(loff_t pos)
1913 {
1914 	struct net_device *dev;
1915 	loff_t i;
1916 
1917 	for (i = 0, dev = dev_base; dev && i < pos; ++i, dev = dev->next);
1918 
1919 	return i == pos ? dev : NULL;
1920 }
1921 
1922 void *dev_seq_start(struct seq_file *seq, loff_t *pos)
1923 {
1924 	read_lock(&dev_base_lock);
1925 	return *pos ? dev_get_idx(*pos - 1) : SEQ_START_TOKEN;
1926 }
1927 
1928 void *dev_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1929 {
1930 	++*pos;
1931 	return v == SEQ_START_TOKEN ? dev_base : ((struct net_device *)v)->next;
1932 }
1933 
1934 void dev_seq_stop(struct seq_file *seq, void *v)
1935 {
1936 	read_unlock(&dev_base_lock);
1937 }
1938 
1939 static void dev_seq_printf_stats(struct seq_file *seq, struct net_device *dev)
1940 {
1941 	if (dev->get_stats) {
1942 		struct net_device_stats *stats = dev->get_stats(dev);
1943 
1944 		seq_printf(seq, "%6s:%8lu %7lu %4lu %4lu %4lu %5lu %10lu %9lu "
1945 				"%8lu %7lu %4lu %4lu %4lu %5lu %7lu %10lu\n",
1946 			   dev->name, stats->rx_bytes, stats->rx_packets,
1947 			   stats->rx_errors,
1948 			   stats->rx_dropped + stats->rx_missed_errors,
1949 			   stats->rx_fifo_errors,
1950 			   stats->rx_length_errors + stats->rx_over_errors +
1951 			     stats->rx_crc_errors + stats->rx_frame_errors,
1952 			   stats->rx_compressed, stats->multicast,
1953 			   stats->tx_bytes, stats->tx_packets,
1954 			   stats->tx_errors, stats->tx_dropped,
1955 			   stats->tx_fifo_errors, stats->collisions,
1956 			   stats->tx_carrier_errors +
1957 			     stats->tx_aborted_errors +
1958 			     stats->tx_window_errors +
1959 			     stats->tx_heartbeat_errors,
1960 			   stats->tx_compressed);
1961 	} else
1962 		seq_printf(seq, "%6s: No statistics available.\n", dev->name);
1963 }
1964 
1965 /*
1966  *	Called from the PROCfs module. This now uses the new arbitrary sized
1967  *	/proc/net interface to create /proc/net/dev
1968  */
1969 static int dev_seq_show(struct seq_file *seq, void *v)
1970 {
1971 	if (v == SEQ_START_TOKEN)
1972 		seq_puts(seq, "Inter-|   Receive                            "
1973 			      "                    |  Transmit\n"
1974 			      " face |bytes    packets errs drop fifo frame "
1975 			      "compressed multicast|bytes    packets errs "
1976 			      "drop fifo colls carrier compressed\n");
1977 	else
1978 		dev_seq_printf_stats(seq, v);
1979 	return 0;
1980 }
1981 
1982 static struct netif_rx_stats *softnet_get_online(loff_t *pos)
1983 {
1984 	struct netif_rx_stats *rc = NULL;
1985 
1986 	while (*pos < NR_CPUS)
1987 	       	if (cpu_online(*pos)) {
1988 			rc = &per_cpu(netdev_rx_stat, *pos);
1989 			break;
1990 		} else
1991 			++*pos;
1992 	return rc;
1993 }
1994 
1995 static void *softnet_seq_start(struct seq_file *seq, loff_t *pos)
1996 {
1997 	return softnet_get_online(pos);
1998 }
1999 
2000 static void *softnet_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2001 {
2002 	++*pos;
2003 	return softnet_get_online(pos);
2004 }
2005 
2006 static void softnet_seq_stop(struct seq_file *seq, void *v)
2007 {
2008 }
2009 
2010 static int softnet_seq_show(struct seq_file *seq, void *v)
2011 {
2012 	struct netif_rx_stats *s = v;
2013 
2014 	seq_printf(seq, "%08x %08x %08x %08x %08x %08x %08x %08x %08x\n",
2015 		   s->total, s->dropped, s->time_squeeze, 0,
2016 		   0, 0, 0, 0, /* was fastroute */
2017 		   s->cpu_collision );
2018 	return 0;
2019 }
2020 
2021 static struct seq_operations dev_seq_ops = {
2022 	.start = dev_seq_start,
2023 	.next  = dev_seq_next,
2024 	.stop  = dev_seq_stop,
2025 	.show  = dev_seq_show,
2026 };
2027 
2028 static int dev_seq_open(struct inode *inode, struct file *file)
2029 {
2030 	return seq_open(file, &dev_seq_ops);
2031 }
2032 
2033 static struct file_operations dev_seq_fops = {
2034 	.owner	 = THIS_MODULE,
2035 	.open    = dev_seq_open,
2036 	.read    = seq_read,
2037 	.llseek  = seq_lseek,
2038 	.release = seq_release,
2039 };
2040 
2041 static struct seq_operations softnet_seq_ops = {
2042 	.start = softnet_seq_start,
2043 	.next  = softnet_seq_next,
2044 	.stop  = softnet_seq_stop,
2045 	.show  = softnet_seq_show,
2046 };
2047 
2048 static int softnet_seq_open(struct inode *inode, struct file *file)
2049 {
2050 	return seq_open(file, &softnet_seq_ops);
2051 }
2052 
2053 static struct file_operations softnet_seq_fops = {
2054 	.owner	 = THIS_MODULE,
2055 	.open    = softnet_seq_open,
2056 	.read    = seq_read,
2057 	.llseek  = seq_lseek,
2058 	.release = seq_release,
2059 };
2060 
2061 #ifdef CONFIG_WIRELESS_EXT
2062 extern int wireless_proc_init(void);
2063 #else
2064 #define wireless_proc_init() 0
2065 #endif
2066 
2067 static int __init dev_proc_init(void)
2068 {
2069 	int rc = -ENOMEM;
2070 
2071 	if (!proc_net_fops_create("dev", S_IRUGO, &dev_seq_fops))
2072 		goto out;
2073 	if (!proc_net_fops_create("softnet_stat", S_IRUGO, &softnet_seq_fops))
2074 		goto out_dev;
2075 	if (wireless_proc_init())
2076 		goto out_softnet;
2077 	rc = 0;
2078 out:
2079 	return rc;
2080 out_softnet:
2081 	proc_net_remove("softnet_stat");
2082 out_dev:
2083 	proc_net_remove("dev");
2084 	goto out;
2085 }
2086 #else
2087 #define dev_proc_init() 0
2088 #endif	/* CONFIG_PROC_FS */
2089 
2090 
2091 /**
2092  *	netdev_set_master	-	set up master/slave pair
2093  *	@slave: slave device
2094  *	@master: new master device
2095  *
2096  *	Changes the master device of the slave. Pass %NULL to break the
2097  *	bonding. The caller must hold the RTNL semaphore. On a failure
2098  *	a negative errno code is returned. On success the reference counts
2099  *	are adjusted, %RTM_NEWLINK is sent to the routing socket and the
2100  *	function returns zero.
2101  */
2102 int netdev_set_master(struct net_device *slave, struct net_device *master)
2103 {
2104 	struct net_device *old = slave->master;
2105 
2106 	ASSERT_RTNL();
2107 
2108 	if (master) {
2109 		if (old)
2110 			return -EBUSY;
2111 		dev_hold(master);
2112 	}
2113 
2114 	slave->master = master;
2115 
2116 	synchronize_net();
2117 
2118 	if (old)
2119 		dev_put(old);
2120 
2121 	if (master)
2122 		slave->flags |= IFF_SLAVE;
2123 	else
2124 		slave->flags &= ~IFF_SLAVE;
2125 
2126 	rtmsg_ifinfo(RTM_NEWLINK, slave, IFF_SLAVE);
2127 	return 0;
2128 }
2129 
2130 /**
2131  *	dev_set_promiscuity	- update promiscuity count on a device
2132  *	@dev: device
2133  *	@inc: modifier
2134  *
2135  *	Add or remove promsicuity from a device. While the count in the device
2136  *	remains above zero the interface remains promiscuous. Once it hits zero
2137  *	the device reverts back to normal filtering operation. A negative inc
2138  *	value is used to drop promiscuity on the device.
2139  */
2140 void dev_set_promiscuity(struct net_device *dev, int inc)
2141 {
2142 	unsigned short old_flags = dev->flags;
2143 
2144 	if ((dev->promiscuity += inc) == 0)
2145 		dev->flags &= ~IFF_PROMISC;
2146 	else
2147 		dev->flags |= IFF_PROMISC;
2148 	if (dev->flags != old_flags) {
2149 		dev_mc_upload(dev);
2150 		printk(KERN_INFO "device %s %s promiscuous mode\n",
2151 		       dev->name, (dev->flags & IFF_PROMISC) ? "entered" :
2152 		       					       "left");
2153 		audit_log(current->audit_context, GFP_ATOMIC,
2154 			AUDIT_ANOM_PROMISCUOUS,
2155 			"dev=%s prom=%d old_prom=%d auid=%u",
2156 			dev->name, (dev->flags & IFF_PROMISC),
2157 			(old_flags & IFF_PROMISC),
2158 			audit_get_loginuid(current->audit_context));
2159 	}
2160 }
2161 
2162 /**
2163  *	dev_set_allmulti	- update allmulti count on a device
2164  *	@dev: device
2165  *	@inc: modifier
2166  *
2167  *	Add or remove reception of all multicast frames to a device. While the
2168  *	count in the device remains above zero the interface remains listening
2169  *	to all interfaces. Once it hits zero the device reverts back to normal
2170  *	filtering operation. A negative @inc value is used to drop the counter
2171  *	when releasing a resource needing all multicasts.
2172  */
2173 
2174 void dev_set_allmulti(struct net_device *dev, int inc)
2175 {
2176 	unsigned short old_flags = dev->flags;
2177 
2178 	dev->flags |= IFF_ALLMULTI;
2179 	if ((dev->allmulti += inc) == 0)
2180 		dev->flags &= ~IFF_ALLMULTI;
2181 	if (dev->flags ^ old_flags)
2182 		dev_mc_upload(dev);
2183 }
2184 
2185 unsigned dev_get_flags(const struct net_device *dev)
2186 {
2187 	unsigned flags;
2188 
2189 	flags = (dev->flags & ~(IFF_PROMISC |
2190 				IFF_ALLMULTI |
2191 				IFF_RUNNING |
2192 				IFF_LOWER_UP |
2193 				IFF_DORMANT)) |
2194 		(dev->gflags & (IFF_PROMISC |
2195 				IFF_ALLMULTI));
2196 
2197 	if (netif_running(dev)) {
2198 		if (netif_oper_up(dev))
2199 			flags |= IFF_RUNNING;
2200 		if (netif_carrier_ok(dev))
2201 			flags |= IFF_LOWER_UP;
2202 		if (netif_dormant(dev))
2203 			flags |= IFF_DORMANT;
2204 	}
2205 
2206 	return flags;
2207 }
2208 
2209 int dev_change_flags(struct net_device *dev, unsigned flags)
2210 {
2211 	int ret;
2212 	int old_flags = dev->flags;
2213 
2214 	/*
2215 	 *	Set the flags on our device.
2216 	 */
2217 
2218 	dev->flags = (flags & (IFF_DEBUG | IFF_NOTRAILERS | IFF_NOARP |
2219 			       IFF_DYNAMIC | IFF_MULTICAST | IFF_PORTSEL |
2220 			       IFF_AUTOMEDIA)) |
2221 		     (dev->flags & (IFF_UP | IFF_VOLATILE | IFF_PROMISC |
2222 				    IFF_ALLMULTI));
2223 
2224 	/*
2225 	 *	Load in the correct multicast list now the flags have changed.
2226 	 */
2227 
2228 	dev_mc_upload(dev);
2229 
2230 	/*
2231 	 *	Have we downed the interface. We handle IFF_UP ourselves
2232 	 *	according to user attempts to set it, rather than blindly
2233 	 *	setting it.
2234 	 */
2235 
2236 	ret = 0;
2237 	if ((old_flags ^ flags) & IFF_UP) {	/* Bit is different  ? */
2238 		ret = ((old_flags & IFF_UP) ? dev_close : dev_open)(dev);
2239 
2240 		if (!ret)
2241 			dev_mc_upload(dev);
2242 	}
2243 
2244 	if (dev->flags & IFF_UP &&
2245 	    ((old_flags ^ dev->flags) &~ (IFF_UP | IFF_PROMISC | IFF_ALLMULTI |
2246 					  IFF_VOLATILE)))
2247 		blocking_notifier_call_chain(&netdev_chain,
2248 				NETDEV_CHANGE, dev);
2249 
2250 	if ((flags ^ dev->gflags) & IFF_PROMISC) {
2251 		int inc = (flags & IFF_PROMISC) ? +1 : -1;
2252 		dev->gflags ^= IFF_PROMISC;
2253 		dev_set_promiscuity(dev, inc);
2254 	}
2255 
2256 	/* NOTE: order of synchronization of IFF_PROMISC and IFF_ALLMULTI
2257 	   is important. Some (broken) drivers set IFF_PROMISC, when
2258 	   IFF_ALLMULTI is requested not asking us and not reporting.
2259 	 */
2260 	if ((flags ^ dev->gflags) & IFF_ALLMULTI) {
2261 		int inc = (flags & IFF_ALLMULTI) ? +1 : -1;
2262 		dev->gflags ^= IFF_ALLMULTI;
2263 		dev_set_allmulti(dev, inc);
2264 	}
2265 
2266 	if (old_flags ^ dev->flags)
2267 		rtmsg_ifinfo(RTM_NEWLINK, dev, old_flags ^ dev->flags);
2268 
2269 	return ret;
2270 }
2271 
2272 int dev_set_mtu(struct net_device *dev, int new_mtu)
2273 {
2274 	int err;
2275 
2276 	if (new_mtu == dev->mtu)
2277 		return 0;
2278 
2279 	/*	MTU must be positive.	 */
2280 	if (new_mtu < 0)
2281 		return -EINVAL;
2282 
2283 	if (!netif_device_present(dev))
2284 		return -ENODEV;
2285 
2286 	err = 0;
2287 	if (dev->change_mtu)
2288 		err = dev->change_mtu(dev, new_mtu);
2289 	else
2290 		dev->mtu = new_mtu;
2291 	if (!err && dev->flags & IFF_UP)
2292 		blocking_notifier_call_chain(&netdev_chain,
2293 				NETDEV_CHANGEMTU, dev);
2294 	return err;
2295 }
2296 
2297 int dev_set_mac_address(struct net_device *dev, struct sockaddr *sa)
2298 {
2299 	int err;
2300 
2301 	if (!dev->set_mac_address)
2302 		return -EOPNOTSUPP;
2303 	if (sa->sa_family != dev->type)
2304 		return -EINVAL;
2305 	if (!netif_device_present(dev))
2306 		return -ENODEV;
2307 	err = dev->set_mac_address(dev, sa);
2308 	if (!err)
2309 		blocking_notifier_call_chain(&netdev_chain,
2310 				NETDEV_CHANGEADDR, dev);
2311 	return err;
2312 }
2313 
2314 /*
2315  *	Perform the SIOCxIFxxx calls.
2316  */
2317 static int dev_ifsioc(struct ifreq *ifr, unsigned int cmd)
2318 {
2319 	int err;
2320 	struct net_device *dev = __dev_get_by_name(ifr->ifr_name);
2321 
2322 	if (!dev)
2323 		return -ENODEV;
2324 
2325 	switch (cmd) {
2326 		case SIOCGIFFLAGS:	/* Get interface flags */
2327 			ifr->ifr_flags = dev_get_flags(dev);
2328 			return 0;
2329 
2330 		case SIOCSIFFLAGS:	/* Set interface flags */
2331 			return dev_change_flags(dev, ifr->ifr_flags);
2332 
2333 		case SIOCGIFMETRIC:	/* Get the metric on the interface
2334 					   (currently unused) */
2335 			ifr->ifr_metric = 0;
2336 			return 0;
2337 
2338 		case SIOCSIFMETRIC:	/* Set the metric on the interface
2339 					   (currently unused) */
2340 			return -EOPNOTSUPP;
2341 
2342 		case SIOCGIFMTU:	/* Get the MTU of a device */
2343 			ifr->ifr_mtu = dev->mtu;
2344 			return 0;
2345 
2346 		case SIOCSIFMTU:	/* Set the MTU of a device */
2347 			return dev_set_mtu(dev, ifr->ifr_mtu);
2348 
2349 		case SIOCGIFHWADDR:
2350 			if (!dev->addr_len)
2351 				memset(ifr->ifr_hwaddr.sa_data, 0, sizeof ifr->ifr_hwaddr.sa_data);
2352 			else
2353 				memcpy(ifr->ifr_hwaddr.sa_data, dev->dev_addr,
2354 				       min(sizeof ifr->ifr_hwaddr.sa_data, (size_t) dev->addr_len));
2355 			ifr->ifr_hwaddr.sa_family = dev->type;
2356 			return 0;
2357 
2358 		case SIOCSIFHWADDR:
2359 			return dev_set_mac_address(dev, &ifr->ifr_hwaddr);
2360 
2361 		case SIOCSIFHWBROADCAST:
2362 			if (ifr->ifr_hwaddr.sa_family != dev->type)
2363 				return -EINVAL;
2364 			memcpy(dev->broadcast, ifr->ifr_hwaddr.sa_data,
2365 			       min(sizeof ifr->ifr_hwaddr.sa_data, (size_t) dev->addr_len));
2366 			blocking_notifier_call_chain(&netdev_chain,
2367 					    NETDEV_CHANGEADDR, dev);
2368 			return 0;
2369 
2370 		case SIOCGIFMAP:
2371 			ifr->ifr_map.mem_start = dev->mem_start;
2372 			ifr->ifr_map.mem_end   = dev->mem_end;
2373 			ifr->ifr_map.base_addr = dev->base_addr;
2374 			ifr->ifr_map.irq       = dev->irq;
2375 			ifr->ifr_map.dma       = dev->dma;
2376 			ifr->ifr_map.port      = dev->if_port;
2377 			return 0;
2378 
2379 		case SIOCSIFMAP:
2380 			if (dev->set_config) {
2381 				if (!netif_device_present(dev))
2382 					return -ENODEV;
2383 				return dev->set_config(dev, &ifr->ifr_map);
2384 			}
2385 			return -EOPNOTSUPP;
2386 
2387 		case SIOCADDMULTI:
2388 			if (!dev->set_multicast_list ||
2389 			    ifr->ifr_hwaddr.sa_family != AF_UNSPEC)
2390 				return -EINVAL;
2391 			if (!netif_device_present(dev))
2392 				return -ENODEV;
2393 			return dev_mc_add(dev, ifr->ifr_hwaddr.sa_data,
2394 					  dev->addr_len, 1);
2395 
2396 		case SIOCDELMULTI:
2397 			if (!dev->set_multicast_list ||
2398 			    ifr->ifr_hwaddr.sa_family != AF_UNSPEC)
2399 				return -EINVAL;
2400 			if (!netif_device_present(dev))
2401 				return -ENODEV;
2402 			return dev_mc_delete(dev, ifr->ifr_hwaddr.sa_data,
2403 					     dev->addr_len, 1);
2404 
2405 		case SIOCGIFINDEX:
2406 			ifr->ifr_ifindex = dev->ifindex;
2407 			return 0;
2408 
2409 		case SIOCGIFTXQLEN:
2410 			ifr->ifr_qlen = dev->tx_queue_len;
2411 			return 0;
2412 
2413 		case SIOCSIFTXQLEN:
2414 			if (ifr->ifr_qlen < 0)
2415 				return -EINVAL;
2416 			dev->tx_queue_len = ifr->ifr_qlen;
2417 			return 0;
2418 
2419 		case SIOCSIFNAME:
2420 			ifr->ifr_newname[IFNAMSIZ-1] = '\0';
2421 			return dev_change_name(dev, ifr->ifr_newname);
2422 
2423 		/*
2424 		 *	Unknown or private ioctl
2425 		 */
2426 
2427 		default:
2428 			if ((cmd >= SIOCDEVPRIVATE &&
2429 			    cmd <= SIOCDEVPRIVATE + 15) ||
2430 			    cmd == SIOCBONDENSLAVE ||
2431 			    cmd == SIOCBONDRELEASE ||
2432 			    cmd == SIOCBONDSETHWADDR ||
2433 			    cmd == SIOCBONDSLAVEINFOQUERY ||
2434 			    cmd == SIOCBONDINFOQUERY ||
2435 			    cmd == SIOCBONDCHANGEACTIVE ||
2436 			    cmd == SIOCGMIIPHY ||
2437 			    cmd == SIOCGMIIREG ||
2438 			    cmd == SIOCSMIIREG ||
2439 			    cmd == SIOCBRADDIF ||
2440 			    cmd == SIOCBRDELIF ||
2441 			    cmd == SIOCWANDEV) {
2442 				err = -EOPNOTSUPP;
2443 				if (dev->do_ioctl) {
2444 					if (netif_device_present(dev))
2445 						err = dev->do_ioctl(dev, ifr,
2446 								    cmd);
2447 					else
2448 						err = -ENODEV;
2449 				}
2450 			} else
2451 				err = -EINVAL;
2452 
2453 	}
2454 	return err;
2455 }
2456 
2457 /*
2458  *	This function handles all "interface"-type I/O control requests. The actual
2459  *	'doing' part of this is dev_ifsioc above.
2460  */
2461 
2462 /**
2463  *	dev_ioctl	-	network device ioctl
2464  *	@cmd: command to issue
2465  *	@arg: pointer to a struct ifreq in user space
2466  *
2467  *	Issue ioctl functions to devices. This is normally called by the
2468  *	user space syscall interfaces but can sometimes be useful for
2469  *	other purposes. The return value is the return from the syscall if
2470  *	positive or a negative errno code on error.
2471  */
2472 
2473 int dev_ioctl(unsigned int cmd, void __user *arg)
2474 {
2475 	struct ifreq ifr;
2476 	int ret;
2477 	char *colon;
2478 
2479 	/* One special case: SIOCGIFCONF takes ifconf argument
2480 	   and requires shared lock, because it sleeps writing
2481 	   to user space.
2482 	 */
2483 
2484 	if (cmd == SIOCGIFCONF) {
2485 		rtnl_lock();
2486 		ret = dev_ifconf((char __user *) arg);
2487 		rtnl_unlock();
2488 		return ret;
2489 	}
2490 	if (cmd == SIOCGIFNAME)
2491 		return dev_ifname((struct ifreq __user *)arg);
2492 
2493 	if (copy_from_user(&ifr, arg, sizeof(struct ifreq)))
2494 		return -EFAULT;
2495 
2496 	ifr.ifr_name[IFNAMSIZ-1] = 0;
2497 
2498 	colon = strchr(ifr.ifr_name, ':');
2499 	if (colon)
2500 		*colon = 0;
2501 
2502 	/*
2503 	 *	See which interface the caller is talking about.
2504 	 */
2505 
2506 	switch (cmd) {
2507 		/*
2508 		 *	These ioctl calls:
2509 		 *	- can be done by all.
2510 		 *	- atomic and do not require locking.
2511 		 *	- return a value
2512 		 */
2513 		case SIOCGIFFLAGS:
2514 		case SIOCGIFMETRIC:
2515 		case SIOCGIFMTU:
2516 		case SIOCGIFHWADDR:
2517 		case SIOCGIFSLAVE:
2518 		case SIOCGIFMAP:
2519 		case SIOCGIFINDEX:
2520 		case SIOCGIFTXQLEN:
2521 			dev_load(ifr.ifr_name);
2522 			read_lock(&dev_base_lock);
2523 			ret = dev_ifsioc(&ifr, cmd);
2524 			read_unlock(&dev_base_lock);
2525 			if (!ret) {
2526 				if (colon)
2527 					*colon = ':';
2528 				if (copy_to_user(arg, &ifr,
2529 						 sizeof(struct ifreq)))
2530 					ret = -EFAULT;
2531 			}
2532 			return ret;
2533 
2534 		case SIOCETHTOOL:
2535 			dev_load(ifr.ifr_name);
2536 			rtnl_lock();
2537 			ret = dev_ethtool(&ifr);
2538 			rtnl_unlock();
2539 			if (!ret) {
2540 				if (colon)
2541 					*colon = ':';
2542 				if (copy_to_user(arg, &ifr,
2543 						 sizeof(struct ifreq)))
2544 					ret = -EFAULT;
2545 			}
2546 			return ret;
2547 
2548 		/*
2549 		 *	These ioctl calls:
2550 		 *	- require superuser power.
2551 		 *	- require strict serialization.
2552 		 *	- return a value
2553 		 */
2554 		case SIOCGMIIPHY:
2555 		case SIOCGMIIREG:
2556 		case SIOCSIFNAME:
2557 			if (!capable(CAP_NET_ADMIN))
2558 				return -EPERM;
2559 			dev_load(ifr.ifr_name);
2560 			rtnl_lock();
2561 			ret = dev_ifsioc(&ifr, cmd);
2562 			rtnl_unlock();
2563 			if (!ret) {
2564 				if (colon)
2565 					*colon = ':';
2566 				if (copy_to_user(arg, &ifr,
2567 						 sizeof(struct ifreq)))
2568 					ret = -EFAULT;
2569 			}
2570 			return ret;
2571 
2572 		/*
2573 		 *	These ioctl calls:
2574 		 *	- require superuser power.
2575 		 *	- require strict serialization.
2576 		 *	- do not return a value
2577 		 */
2578 		case SIOCSIFFLAGS:
2579 		case SIOCSIFMETRIC:
2580 		case SIOCSIFMTU:
2581 		case SIOCSIFMAP:
2582 		case SIOCSIFHWADDR:
2583 		case SIOCSIFSLAVE:
2584 		case SIOCADDMULTI:
2585 		case SIOCDELMULTI:
2586 		case SIOCSIFHWBROADCAST:
2587 		case SIOCSIFTXQLEN:
2588 		case SIOCSMIIREG:
2589 		case SIOCBONDENSLAVE:
2590 		case SIOCBONDRELEASE:
2591 		case SIOCBONDSETHWADDR:
2592 		case SIOCBONDCHANGEACTIVE:
2593 		case SIOCBRADDIF:
2594 		case SIOCBRDELIF:
2595 			if (!capable(CAP_NET_ADMIN))
2596 				return -EPERM;
2597 			/* fall through */
2598 		case SIOCBONDSLAVEINFOQUERY:
2599 		case SIOCBONDINFOQUERY:
2600 			dev_load(ifr.ifr_name);
2601 			rtnl_lock();
2602 			ret = dev_ifsioc(&ifr, cmd);
2603 			rtnl_unlock();
2604 			return ret;
2605 
2606 		case SIOCGIFMEM:
2607 			/* Get the per device memory space. We can add this but
2608 			 * currently do not support it */
2609 		case SIOCSIFMEM:
2610 			/* Set the per device memory buffer space.
2611 			 * Not applicable in our case */
2612 		case SIOCSIFLINK:
2613 			return -EINVAL;
2614 
2615 		/*
2616 		 *	Unknown or private ioctl.
2617 		 */
2618 		default:
2619 			if (cmd == SIOCWANDEV ||
2620 			    (cmd >= SIOCDEVPRIVATE &&
2621 			     cmd <= SIOCDEVPRIVATE + 15)) {
2622 				dev_load(ifr.ifr_name);
2623 				rtnl_lock();
2624 				ret = dev_ifsioc(&ifr, cmd);
2625 				rtnl_unlock();
2626 				if (!ret && copy_to_user(arg, &ifr,
2627 							 sizeof(struct ifreq)))
2628 					ret = -EFAULT;
2629 				return ret;
2630 			}
2631 #ifdef CONFIG_WIRELESS_EXT
2632 			/* Take care of Wireless Extensions */
2633 			if (cmd >= SIOCIWFIRST && cmd <= SIOCIWLAST) {
2634 				/* If command is `set a parameter', or
2635 				 * `get the encoding parameters', check if
2636 				 * the user has the right to do it */
2637 				if (IW_IS_SET(cmd) || cmd == SIOCGIWENCODE) {
2638 					if (!capable(CAP_NET_ADMIN))
2639 						return -EPERM;
2640 				}
2641 				dev_load(ifr.ifr_name);
2642 				rtnl_lock();
2643 				/* Follow me in net/core/wireless.c */
2644 				ret = wireless_process_ioctl(&ifr, cmd);
2645 				rtnl_unlock();
2646 				if (IW_IS_GET(cmd) &&
2647 				    copy_to_user(arg, &ifr,
2648 					    	 sizeof(struct ifreq)))
2649 					ret = -EFAULT;
2650 				return ret;
2651 			}
2652 #endif	/* CONFIG_WIRELESS_EXT */
2653 			return -EINVAL;
2654 	}
2655 }
2656 
2657 
2658 /**
2659  *	dev_new_index	-	allocate an ifindex
2660  *
2661  *	Returns a suitable unique value for a new device interface
2662  *	number.  The caller must hold the rtnl semaphore or the
2663  *	dev_base_lock to be sure it remains unique.
2664  */
2665 static int dev_new_index(void)
2666 {
2667 	static int ifindex;
2668 	for (;;) {
2669 		if (++ifindex <= 0)
2670 			ifindex = 1;
2671 		if (!__dev_get_by_index(ifindex))
2672 			return ifindex;
2673 	}
2674 }
2675 
2676 static int dev_boot_phase = 1;
2677 
2678 /* Delayed registration/unregisteration */
2679 static DEFINE_SPINLOCK(net_todo_list_lock);
2680 static struct list_head net_todo_list = LIST_HEAD_INIT(net_todo_list);
2681 
2682 static inline void net_set_todo(struct net_device *dev)
2683 {
2684 	spin_lock(&net_todo_list_lock);
2685 	list_add_tail(&dev->todo_list, &net_todo_list);
2686 	spin_unlock(&net_todo_list_lock);
2687 }
2688 
2689 /**
2690  *	register_netdevice	- register a network device
2691  *	@dev: device to register
2692  *
2693  *	Take a completed network device structure and add it to the kernel
2694  *	interfaces. A %NETDEV_REGISTER message is sent to the netdev notifier
2695  *	chain. 0 is returned on success. A negative errno code is returned
2696  *	on a failure to set up the device, or if the name is a duplicate.
2697  *
2698  *	Callers must hold the rtnl semaphore. You may want
2699  *	register_netdev() instead of this.
2700  *
2701  *	BUGS:
2702  *	The locking appears insufficient to guarantee two parallel registers
2703  *	will not get the same name.
2704  */
2705 
2706 int register_netdevice(struct net_device *dev)
2707 {
2708 	struct hlist_head *head;
2709 	struct hlist_node *p;
2710 	int ret;
2711 
2712 	BUG_ON(dev_boot_phase);
2713 	ASSERT_RTNL();
2714 
2715 	/* When net_device's are persistent, this will be fatal. */
2716 	BUG_ON(dev->reg_state != NETREG_UNINITIALIZED);
2717 
2718 	spin_lock_init(&dev->queue_lock);
2719 	spin_lock_init(&dev->xmit_lock);
2720 	dev->xmit_lock_owner = -1;
2721 #ifdef CONFIG_NET_CLS_ACT
2722 	spin_lock_init(&dev->ingress_lock);
2723 #endif
2724 
2725 	ret = alloc_divert_blk(dev);
2726 	if (ret)
2727 		goto out;
2728 
2729 	dev->iflink = -1;
2730 
2731 	/* Init, if this function is available */
2732 	if (dev->init) {
2733 		ret = dev->init(dev);
2734 		if (ret) {
2735 			if (ret > 0)
2736 				ret = -EIO;
2737 			goto out_err;
2738 		}
2739 	}
2740 
2741 	if (!dev_valid_name(dev->name)) {
2742 		ret = -EINVAL;
2743 		goto out_err;
2744 	}
2745 
2746 	dev->ifindex = dev_new_index();
2747 	if (dev->iflink == -1)
2748 		dev->iflink = dev->ifindex;
2749 
2750 	/* Check for existence of name */
2751 	head = dev_name_hash(dev->name);
2752 	hlist_for_each(p, head) {
2753 		struct net_device *d
2754 			= hlist_entry(p, struct net_device, name_hlist);
2755 		if (!strncmp(d->name, dev->name, IFNAMSIZ)) {
2756 			ret = -EEXIST;
2757  			goto out_err;
2758 		}
2759  	}
2760 
2761 	/* Fix illegal SG+CSUM combinations. */
2762 	if ((dev->features & NETIF_F_SG) &&
2763 	    !(dev->features & (NETIF_F_IP_CSUM |
2764 			       NETIF_F_NO_CSUM |
2765 			       NETIF_F_HW_CSUM))) {
2766 		printk("%s: Dropping NETIF_F_SG since no checksum feature.\n",
2767 		       dev->name);
2768 		dev->features &= ~NETIF_F_SG;
2769 	}
2770 
2771 	/* TSO requires that SG is present as well. */
2772 	if ((dev->features & NETIF_F_TSO) &&
2773 	    !(dev->features & NETIF_F_SG)) {
2774 		printk("%s: Dropping NETIF_F_TSO since no SG feature.\n",
2775 		       dev->name);
2776 		dev->features &= ~NETIF_F_TSO;
2777 	}
2778 	if (dev->features & NETIF_F_UFO) {
2779 		if (!(dev->features & NETIF_F_HW_CSUM)) {
2780 			printk(KERN_ERR "%s: Dropping NETIF_F_UFO since no "
2781 					"NETIF_F_HW_CSUM feature.\n",
2782 							dev->name);
2783 			dev->features &= ~NETIF_F_UFO;
2784 		}
2785 		if (!(dev->features & NETIF_F_SG)) {
2786 			printk(KERN_ERR "%s: Dropping NETIF_F_UFO since no "
2787 					"NETIF_F_SG feature.\n",
2788 					dev->name);
2789 			dev->features &= ~NETIF_F_UFO;
2790 		}
2791 	}
2792 
2793 	/*
2794 	 *	nil rebuild_header routine,
2795 	 *	that should be never called and used as just bug trap.
2796 	 */
2797 
2798 	if (!dev->rebuild_header)
2799 		dev->rebuild_header = default_rebuild_header;
2800 
2801 	/*
2802 	 *	Default initial state at registry is that the
2803 	 *	device is present.
2804 	 */
2805 
2806 	set_bit(__LINK_STATE_PRESENT, &dev->state);
2807 
2808 	dev->next = NULL;
2809 	dev_init_scheduler(dev);
2810 	write_lock_bh(&dev_base_lock);
2811 	*dev_tail = dev;
2812 	dev_tail = &dev->next;
2813 	hlist_add_head(&dev->name_hlist, head);
2814 	hlist_add_head(&dev->index_hlist, dev_index_hash(dev->ifindex));
2815 	dev_hold(dev);
2816 	dev->reg_state = NETREG_REGISTERING;
2817 	write_unlock_bh(&dev_base_lock);
2818 
2819 	/* Notify protocols, that a new device appeared. */
2820 	blocking_notifier_call_chain(&netdev_chain, NETDEV_REGISTER, dev);
2821 
2822 	/* Finish registration after unlock */
2823 	net_set_todo(dev);
2824 	ret = 0;
2825 
2826 out:
2827 	return ret;
2828 out_err:
2829 	free_divert_blk(dev);
2830 	goto out;
2831 }
2832 
2833 /**
2834  *	register_netdev	- register a network device
2835  *	@dev: device to register
2836  *
2837  *	Take a completed network device structure and add it to the kernel
2838  *	interfaces. A %NETDEV_REGISTER message is sent to the netdev notifier
2839  *	chain. 0 is returned on success. A negative errno code is returned
2840  *	on a failure to set up the device, or if the name is a duplicate.
2841  *
2842  *	This is a wrapper around register_netdev that takes the rtnl semaphore
2843  *	and expands the device name if you passed a format string to
2844  *	alloc_netdev.
2845  */
2846 int register_netdev(struct net_device *dev)
2847 {
2848 	int err;
2849 
2850 	rtnl_lock();
2851 
2852 	/*
2853 	 * If the name is a format string the caller wants us to do a
2854 	 * name allocation.
2855 	 */
2856 	if (strchr(dev->name, '%')) {
2857 		err = dev_alloc_name(dev, dev->name);
2858 		if (err < 0)
2859 			goto out;
2860 	}
2861 
2862 	/*
2863 	 * Back compatibility hook. Kill this one in 2.5
2864 	 */
2865 	if (dev->name[0] == 0 || dev->name[0] == ' ') {
2866 		err = dev_alloc_name(dev, "eth%d");
2867 		if (err < 0)
2868 			goto out;
2869 	}
2870 
2871 	err = register_netdevice(dev);
2872 out:
2873 	rtnl_unlock();
2874 	return err;
2875 }
2876 EXPORT_SYMBOL(register_netdev);
2877 
2878 /*
2879  * netdev_wait_allrefs - wait until all references are gone.
2880  *
2881  * This is called when unregistering network devices.
2882  *
2883  * Any protocol or device that holds a reference should register
2884  * for netdevice notification, and cleanup and put back the
2885  * reference if they receive an UNREGISTER event.
2886  * We can get stuck here if buggy protocols don't correctly
2887  * call dev_put.
2888  */
2889 static void netdev_wait_allrefs(struct net_device *dev)
2890 {
2891 	unsigned long rebroadcast_time, warning_time;
2892 
2893 	rebroadcast_time = warning_time = jiffies;
2894 	while (atomic_read(&dev->refcnt) != 0) {
2895 		if (time_after(jiffies, rebroadcast_time + 1 * HZ)) {
2896 			rtnl_lock();
2897 
2898 			/* Rebroadcast unregister notification */
2899 			blocking_notifier_call_chain(&netdev_chain,
2900 					    NETDEV_UNREGISTER, dev);
2901 
2902 			if (test_bit(__LINK_STATE_LINKWATCH_PENDING,
2903 				     &dev->state)) {
2904 				/* We must not have linkwatch events
2905 				 * pending on unregister. If this
2906 				 * happens, we simply run the queue
2907 				 * unscheduled, resulting in a noop
2908 				 * for this device.
2909 				 */
2910 				linkwatch_run_queue();
2911 			}
2912 
2913 			__rtnl_unlock();
2914 
2915 			rebroadcast_time = jiffies;
2916 		}
2917 
2918 		msleep(250);
2919 
2920 		if (time_after(jiffies, warning_time + 10 * HZ)) {
2921 			printk(KERN_EMERG "unregister_netdevice: "
2922 			       "waiting for %s to become free. Usage "
2923 			       "count = %d\n",
2924 			       dev->name, atomic_read(&dev->refcnt));
2925 			warning_time = jiffies;
2926 		}
2927 	}
2928 }
2929 
2930 /* The sequence is:
2931  *
2932  *	rtnl_lock();
2933  *	...
2934  *	register_netdevice(x1);
2935  *	register_netdevice(x2);
2936  *	...
2937  *	unregister_netdevice(y1);
2938  *	unregister_netdevice(y2);
2939  *      ...
2940  *	rtnl_unlock();
2941  *	free_netdev(y1);
2942  *	free_netdev(y2);
2943  *
2944  * We are invoked by rtnl_unlock() after it drops the semaphore.
2945  * This allows us to deal with problems:
2946  * 1) We can create/delete sysfs objects which invoke hotplug
2947  *    without deadlocking with linkwatch via keventd.
2948  * 2) Since we run with the RTNL semaphore not held, we can sleep
2949  *    safely in order to wait for the netdev refcnt to drop to zero.
2950  */
2951 static DEFINE_MUTEX(net_todo_run_mutex);
2952 void netdev_run_todo(void)
2953 {
2954 	struct list_head list = LIST_HEAD_INIT(list);
2955 	int err;
2956 
2957 
2958 	/* Need to guard against multiple cpu's getting out of order. */
2959 	mutex_lock(&net_todo_run_mutex);
2960 
2961 	/* Not safe to do outside the semaphore.  We must not return
2962 	 * until all unregister events invoked by the local processor
2963 	 * have been completed (either by this todo run, or one on
2964 	 * another cpu).
2965 	 */
2966 	if (list_empty(&net_todo_list))
2967 		goto out;
2968 
2969 	/* Snapshot list, allow later requests */
2970 	spin_lock(&net_todo_list_lock);
2971 	list_splice_init(&net_todo_list, &list);
2972 	spin_unlock(&net_todo_list_lock);
2973 
2974 	while (!list_empty(&list)) {
2975 		struct net_device *dev
2976 			= list_entry(list.next, struct net_device, todo_list);
2977 		list_del(&dev->todo_list);
2978 
2979 		switch(dev->reg_state) {
2980 		case NETREG_REGISTERING:
2981 			err = netdev_register_sysfs(dev);
2982 			if (err)
2983 				printk(KERN_ERR "%s: failed sysfs registration (%d)\n",
2984 				       dev->name, err);
2985 			dev->reg_state = NETREG_REGISTERED;
2986 			break;
2987 
2988 		case NETREG_UNREGISTERING:
2989 			netdev_unregister_sysfs(dev);
2990 			dev->reg_state = NETREG_UNREGISTERED;
2991 
2992 			netdev_wait_allrefs(dev);
2993 
2994 			/* paranoia */
2995 			BUG_ON(atomic_read(&dev->refcnt));
2996 			BUG_TRAP(!dev->ip_ptr);
2997 			BUG_TRAP(!dev->ip6_ptr);
2998 			BUG_TRAP(!dev->dn_ptr);
2999 
3000 
3001 			/* It must be the very last action,
3002 			 * after this 'dev' may point to freed up memory.
3003 			 */
3004 			if (dev->destructor)
3005 				dev->destructor(dev);
3006 			break;
3007 
3008 		default:
3009 			printk(KERN_ERR "network todo '%s' but state %d\n",
3010 			       dev->name, dev->reg_state);
3011 			break;
3012 		}
3013 	}
3014 
3015 out:
3016 	mutex_unlock(&net_todo_run_mutex);
3017 }
3018 
3019 /**
3020  *	alloc_netdev - allocate network device
3021  *	@sizeof_priv:	size of private data to allocate space for
3022  *	@name:		device name format string
3023  *	@setup:		callback to initialize device
3024  *
3025  *	Allocates a struct net_device with private data area for driver use
3026  *	and performs basic initialization.
3027  */
3028 struct net_device *alloc_netdev(int sizeof_priv, const char *name,
3029 		void (*setup)(struct net_device *))
3030 {
3031 	void *p;
3032 	struct net_device *dev;
3033 	int alloc_size;
3034 
3035 	/* ensure 32-byte alignment of both the device and private area */
3036 	alloc_size = (sizeof(*dev) + NETDEV_ALIGN_CONST) & ~NETDEV_ALIGN_CONST;
3037 	alloc_size += sizeof_priv + NETDEV_ALIGN_CONST;
3038 
3039 	p = kmalloc(alloc_size, GFP_KERNEL);
3040 	if (!p) {
3041 		printk(KERN_ERR "alloc_dev: Unable to allocate device.\n");
3042 		return NULL;
3043 	}
3044 	memset(p, 0, alloc_size);
3045 
3046 	dev = (struct net_device *)
3047 		(((long)p + NETDEV_ALIGN_CONST) & ~NETDEV_ALIGN_CONST);
3048 	dev->padded = (char *)dev - (char *)p;
3049 
3050 	if (sizeof_priv)
3051 		dev->priv = netdev_priv(dev);
3052 
3053 	setup(dev);
3054 	strcpy(dev->name, name);
3055 	return dev;
3056 }
3057 EXPORT_SYMBOL(alloc_netdev);
3058 
3059 /**
3060  *	free_netdev - free network device
3061  *	@dev: device
3062  *
3063  *	This function does the last stage of destroying an allocated device
3064  * 	interface. The reference to the device object is released.
3065  *	If this is the last reference then it will be freed.
3066  */
3067 void free_netdev(struct net_device *dev)
3068 {
3069 #ifdef CONFIG_SYSFS
3070 	/*  Compatiablity with error handling in drivers */
3071 	if (dev->reg_state == NETREG_UNINITIALIZED) {
3072 		kfree((char *)dev - dev->padded);
3073 		return;
3074 	}
3075 
3076 	BUG_ON(dev->reg_state != NETREG_UNREGISTERED);
3077 	dev->reg_state = NETREG_RELEASED;
3078 
3079 	/* will free via class release */
3080 	class_device_put(&dev->class_dev);
3081 #else
3082 	kfree((char *)dev - dev->padded);
3083 #endif
3084 }
3085 
3086 /* Synchronize with packet receive processing. */
3087 void synchronize_net(void)
3088 {
3089 	might_sleep();
3090 	synchronize_rcu();
3091 }
3092 
3093 /**
3094  *	unregister_netdevice - remove device from the kernel
3095  *	@dev: device
3096  *
3097  *	This function shuts down a device interface and removes it
3098  *	from the kernel tables. On success 0 is returned, on a failure
3099  *	a negative errno code is returned.
3100  *
3101  *	Callers must hold the rtnl semaphore.  You may want
3102  *	unregister_netdev() instead of this.
3103  */
3104 
3105 int unregister_netdevice(struct net_device *dev)
3106 {
3107 	struct net_device *d, **dp;
3108 
3109 	BUG_ON(dev_boot_phase);
3110 	ASSERT_RTNL();
3111 
3112 	/* Some devices call without registering for initialization unwind. */
3113 	if (dev->reg_state == NETREG_UNINITIALIZED) {
3114 		printk(KERN_DEBUG "unregister_netdevice: device %s/%p never "
3115 				  "was registered\n", dev->name, dev);
3116 		return -ENODEV;
3117 	}
3118 
3119 	BUG_ON(dev->reg_state != NETREG_REGISTERED);
3120 
3121 	/* If device is running, close it first. */
3122 	if (dev->flags & IFF_UP)
3123 		dev_close(dev);
3124 
3125 	/* And unlink it from device chain. */
3126 	for (dp = &dev_base; (d = *dp) != NULL; dp = &d->next) {
3127 		if (d == dev) {
3128 			write_lock_bh(&dev_base_lock);
3129 			hlist_del(&dev->name_hlist);
3130 			hlist_del(&dev->index_hlist);
3131 			if (dev_tail == &dev->next)
3132 				dev_tail = dp;
3133 			*dp = d->next;
3134 			write_unlock_bh(&dev_base_lock);
3135 			break;
3136 		}
3137 	}
3138 	if (!d) {
3139 		printk(KERN_ERR "unregister net_device: '%s' not found\n",
3140 		       dev->name);
3141 		return -ENODEV;
3142 	}
3143 
3144 	dev->reg_state = NETREG_UNREGISTERING;
3145 
3146 	synchronize_net();
3147 
3148 	/* Shutdown queueing discipline. */
3149 	dev_shutdown(dev);
3150 
3151 
3152 	/* Notify protocols, that we are about to destroy
3153 	   this device. They should clean all the things.
3154 	*/
3155 	blocking_notifier_call_chain(&netdev_chain, NETDEV_UNREGISTER, dev);
3156 
3157 	/*
3158 	 *	Flush the multicast chain
3159 	 */
3160 	dev_mc_discard(dev);
3161 
3162 	if (dev->uninit)
3163 		dev->uninit(dev);
3164 
3165 	/* Notifier chain MUST detach us from master device. */
3166 	BUG_TRAP(!dev->master);
3167 
3168 	free_divert_blk(dev);
3169 
3170 	/* Finish processing unregister after unlock */
3171 	net_set_todo(dev);
3172 
3173 	synchronize_net();
3174 
3175 	dev_put(dev);
3176 	return 0;
3177 }
3178 
3179 /**
3180  *	unregister_netdev - remove device from the kernel
3181  *	@dev: device
3182  *
3183  *	This function shuts down a device interface and removes it
3184  *	from the kernel tables. On success 0 is returned, on a failure
3185  *	a negative errno code is returned.
3186  *
3187  *	This is just a wrapper for unregister_netdevice that takes
3188  *	the rtnl semaphore.  In general you want to use this and not
3189  *	unregister_netdevice.
3190  */
3191 void unregister_netdev(struct net_device *dev)
3192 {
3193 	rtnl_lock();
3194 	unregister_netdevice(dev);
3195 	rtnl_unlock();
3196 }
3197 
3198 EXPORT_SYMBOL(unregister_netdev);
3199 
3200 #ifdef CONFIG_HOTPLUG_CPU
3201 static int dev_cpu_callback(struct notifier_block *nfb,
3202 			    unsigned long action,
3203 			    void *ocpu)
3204 {
3205 	struct sk_buff **list_skb;
3206 	struct net_device **list_net;
3207 	struct sk_buff *skb;
3208 	unsigned int cpu, oldcpu = (unsigned long)ocpu;
3209 	struct softnet_data *sd, *oldsd;
3210 
3211 	if (action != CPU_DEAD)
3212 		return NOTIFY_OK;
3213 
3214 	local_irq_disable();
3215 	cpu = smp_processor_id();
3216 	sd = &per_cpu(softnet_data, cpu);
3217 	oldsd = &per_cpu(softnet_data, oldcpu);
3218 
3219 	/* Find end of our completion_queue. */
3220 	list_skb = &sd->completion_queue;
3221 	while (*list_skb)
3222 		list_skb = &(*list_skb)->next;
3223 	/* Append completion queue from offline CPU. */
3224 	*list_skb = oldsd->completion_queue;
3225 	oldsd->completion_queue = NULL;
3226 
3227 	/* Find end of our output_queue. */
3228 	list_net = &sd->output_queue;
3229 	while (*list_net)
3230 		list_net = &(*list_net)->next_sched;
3231 	/* Append output queue from offline CPU. */
3232 	*list_net = oldsd->output_queue;
3233 	oldsd->output_queue = NULL;
3234 
3235 	raise_softirq_irqoff(NET_TX_SOFTIRQ);
3236 	local_irq_enable();
3237 
3238 	/* Process offline CPU's input_pkt_queue */
3239 	while ((skb = __skb_dequeue(&oldsd->input_pkt_queue)))
3240 		netif_rx(skb);
3241 
3242 	return NOTIFY_OK;
3243 }
3244 #endif /* CONFIG_HOTPLUG_CPU */
3245 
3246 
3247 /*
3248  *	Initialize the DEV module. At boot time this walks the device list and
3249  *	unhooks any devices that fail to initialise (normally hardware not
3250  *	present) and leaves us with a valid list of present and active devices.
3251  *
3252  */
3253 
3254 /*
3255  *       This is called single threaded during boot, so no need
3256  *       to take the rtnl semaphore.
3257  */
3258 static int __init net_dev_init(void)
3259 {
3260 	int i, rc = -ENOMEM;
3261 
3262 	BUG_ON(!dev_boot_phase);
3263 
3264 	net_random_init();
3265 
3266 	if (dev_proc_init())
3267 		goto out;
3268 
3269 	if (netdev_sysfs_init())
3270 		goto out;
3271 
3272 	INIT_LIST_HEAD(&ptype_all);
3273 	for (i = 0; i < 16; i++)
3274 		INIT_LIST_HEAD(&ptype_base[i]);
3275 
3276 	for (i = 0; i < ARRAY_SIZE(dev_name_head); i++)
3277 		INIT_HLIST_HEAD(&dev_name_head[i]);
3278 
3279 	for (i = 0; i < ARRAY_SIZE(dev_index_head); i++)
3280 		INIT_HLIST_HEAD(&dev_index_head[i]);
3281 
3282 	/*
3283 	 *	Initialise the packet receive queues.
3284 	 */
3285 
3286 	for_each_cpu(i) {
3287 		struct softnet_data *queue;
3288 
3289 		queue = &per_cpu(softnet_data, i);
3290 		skb_queue_head_init(&queue->input_pkt_queue);
3291 		queue->completion_queue = NULL;
3292 		INIT_LIST_HEAD(&queue->poll_list);
3293 		set_bit(__LINK_STATE_START, &queue->backlog_dev.state);
3294 		queue->backlog_dev.weight = weight_p;
3295 		queue->backlog_dev.poll = process_backlog;
3296 		atomic_set(&queue->backlog_dev.refcnt, 1);
3297 	}
3298 
3299 	dev_boot_phase = 0;
3300 
3301 	open_softirq(NET_TX_SOFTIRQ, net_tx_action, NULL);
3302 	open_softirq(NET_RX_SOFTIRQ, net_rx_action, NULL);
3303 
3304 	hotcpu_notifier(dev_cpu_callback, 0);
3305 	dst_init();
3306 	dev_mcast_init();
3307 	rc = 0;
3308 out:
3309 	return rc;
3310 }
3311 
3312 subsys_initcall(net_dev_init);
3313 
3314 EXPORT_SYMBOL(__dev_get_by_index);
3315 EXPORT_SYMBOL(__dev_get_by_name);
3316 EXPORT_SYMBOL(__dev_remove_pack);
3317 EXPORT_SYMBOL(__skb_linearize);
3318 EXPORT_SYMBOL(dev_valid_name);
3319 EXPORT_SYMBOL(dev_add_pack);
3320 EXPORT_SYMBOL(dev_alloc_name);
3321 EXPORT_SYMBOL(dev_close);
3322 EXPORT_SYMBOL(dev_get_by_flags);
3323 EXPORT_SYMBOL(dev_get_by_index);
3324 EXPORT_SYMBOL(dev_get_by_name);
3325 EXPORT_SYMBOL(dev_open);
3326 EXPORT_SYMBOL(dev_queue_xmit);
3327 EXPORT_SYMBOL(dev_remove_pack);
3328 EXPORT_SYMBOL(dev_set_allmulti);
3329 EXPORT_SYMBOL(dev_set_promiscuity);
3330 EXPORT_SYMBOL(dev_change_flags);
3331 EXPORT_SYMBOL(dev_set_mtu);
3332 EXPORT_SYMBOL(dev_set_mac_address);
3333 EXPORT_SYMBOL(free_netdev);
3334 EXPORT_SYMBOL(netdev_boot_setup_check);
3335 EXPORT_SYMBOL(netdev_set_master);
3336 EXPORT_SYMBOL(netdev_state_change);
3337 EXPORT_SYMBOL(netif_receive_skb);
3338 EXPORT_SYMBOL(netif_rx);
3339 EXPORT_SYMBOL(register_gifconf);
3340 EXPORT_SYMBOL(register_netdevice);
3341 EXPORT_SYMBOL(register_netdevice_notifier);
3342 EXPORT_SYMBOL(skb_checksum_help);
3343 EXPORT_SYMBOL(synchronize_net);
3344 EXPORT_SYMBOL(unregister_netdevice);
3345 EXPORT_SYMBOL(unregister_netdevice_notifier);
3346 EXPORT_SYMBOL(net_enable_timestamp);
3347 EXPORT_SYMBOL(net_disable_timestamp);
3348 EXPORT_SYMBOL(dev_get_flags);
3349 
3350 #if defined(CONFIG_BRIDGE) || defined(CONFIG_BRIDGE_MODULE)
3351 EXPORT_SYMBOL(br_handle_frame_hook);
3352 EXPORT_SYMBOL(br_fdb_get_hook);
3353 EXPORT_SYMBOL(br_fdb_put_hook);
3354 #endif
3355 
3356 #ifdef CONFIG_KMOD
3357 EXPORT_SYMBOL(dev_load);
3358 #endif
3359 
3360 EXPORT_PER_CPU_SYMBOL(softnet_data);
3361