/*
   * 	NET3	Protocol independent device support routines.
   *
   *		This program is free software; you can redistribute it and/or
   *		modify it under the terms of the GNU General Public License
   *		as published by the Free Software Foundation; either version
   *		2 of the License, or (at your option) any later version.
   *
   *	Derived from the non IP parts of dev.c 1.0.19

   * 		Authors:	Ross Biro

   *				Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
   *				Mark Evans, <evansmp@uhura.aston.ac.uk>
   *
   *	Additional Authors:
   *		Florian la Roche <rzsfl@rz.uni-sb.de>
   *		Alan Cox <gw4pts@gw4pts.ampr.org>
   *		David Hinds <dahinds@users.sourceforge.net>
   *		Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
   *		Adam Sulmicki <adam@cfar.umd.edu>
   *              Pekka Riikonen <priikone@poesidon.pspt.fi>
   *
   *	Changes:
   *              D.J. Barrow     :       Fixed bug where dev->refcnt gets set
   *              			to 2 if register_netdev gets called
   *              			before net_dev_init & also removed a
   *              			few lines of code in the process.
   *		Alan Cox	:	device private ioctl copies fields back.
   *		Alan Cox	:	Transmit queue code does relevant
   *					stunts to keep the queue safe.
   *		Alan Cox	:	Fixed double lock.
   *		Alan Cox	:	Fixed promisc NULL pointer trap
   *		????????	:	Support the full private ioctl range
   *		Alan Cox	:	Moved ioctl permission check into
   *					drivers
   *		Tim Kordas	:	SIOCADDMULTI/SIOCDELMULTI
   *		Alan Cox	:	100 backlog just doesn't cut it when
   *					you start doing multicast video 8)
   *		Alan Cox	:	Rewrote net_bh and list manager.
   *		Alan Cox	: 	Fix ETH_P_ALL echoback lengths.
   *		Alan Cox	:	Took out transmit every packet pass
   *					Saved a few bytes in the ioctl handler
   *		Alan Cox	:	Network driver sets packet type before
   *					calling netif_rx. Saves a function
   *					call a packet.
   *		Alan Cox	:	Hashed net_bh()
   *		Richard Kooijman:	Timestamp fixes.
   *		Alan Cox	:	Wrong field in SIOCGIFDSTADDR
   *		Alan Cox	:	Device lock protection.
   *		Alan Cox	: 	Fixed nasty side effect of device close
   *					changes.
   *		Rudi Cilibrasi	:	Pass the right thing to
   *					set_mac_address()
   *		Dave Miller	:	32bit quantity for the device lock to
   *					make it work out on a Sparc.
   *		Bjorn Ekwall	:	Added KERNELD hack.
   *		Alan Cox	:	Cleaned up the backlog initialise.
   *		Craig Metz	:	SIOCGIFCONF fix if space for under
   *					1 device.
   *	    Thomas Bogendoerfer :	Return ENODEV for dev_open, if there
   *					is no device open function.
   *		Andi Kleen	:	Fix error reporting for SIOCGIFCONF
   *	    Michael Chastain	:	Fix signed/unsigned for SIOCGIFCONF
   *		Cyrus Durgin	:	Cleaned for KMOD
   *		Adam Sulmicki   :	Bug Fix : Network Device Unload
   *					A network device unload needs to purge
   *					the backlog queue.
   *	Paul Rusty Russell	:	SIOCSIFNAME
   *              Pekka Riikonen  :	Netdev boot-time settings code
   *              Andrew Morton   :       Make unregister_netdevice wait
   *              			indefinitely on dev->refcnt
   * 		J Hadi Salim	:	- Backlog queue sampling
   *				        - netif_rx() feedback
   */
  
  #include <asm/uaccess.h>
  #include <asm/system.h>
  #include <linux/bitops.h>

  #include <linux/capability.h>

  #include <linux/cpu.h>
  #include <linux/types.h>
  #include <linux/kernel.h>
  #include <linux/sched.h>

  #include <linux/mutex.h>

  #include <linux/string.h>
  #include <linux/mm.h>
  #include <linux/socket.h>
  #include <linux/sockios.h>
  #include <linux/errno.h>
  #include <linux/interrupt.h>
  #include <linux/if_ether.h>
  #include <linux/netdevice.h>
  #include <linux/etherdevice.h>
  #include <linux/notifier.h>
  #include <linux/skbuff.h>

  #include <net/net_namespace.h>

  #include <net/sock.h>
  #include <linux/rtnetlink.h>
  #include <linux/proc_fs.h>
  #include <linux/seq_file.h>
  #include <linux/stat.h>
  #include <linux/if_bridge.h>

  #include <linux/if_macvlan.h>

  #include <net/dst.h>
  #include <net/pkt_sched.h>
  #include <net/checksum.h>
  #include <linux/highmem.h>
  #include <linux/init.h>
  #include <linux/kmod.h>
  #include <linux/module.h>
  #include <linux/kallsyms.h>
  #include <linux/netpoll.h>
  #include <linux/rcupdate.h>
  #include <linux/delay.h>

  #include <net/wext.h>

  #include <net/iw_handler.h>

  #include <asm/current.h>

  #include <linux/audit.h>

  #include <linux/dmaengine.h>

  #include <linux/err.h>

  #include <linux/ctype.h>

  #include <linux/if_arp.h>

  #include <linux/if_vlan.h>

  #include "net-sysfs.h"

  /*
   *	The list of packet types we will receive (as opposed to discard)
   *	and the routines to invoke.
   *
   *	Why 16. Because with 16 the only overlap we get on a hash of the
   *	low nibble of the protocol value is RARP/SNAP/X.25.
   *
   *      NOTE:  That is no longer true with the addition of VLAN tags.  Not
   *             sure which should go first, but I bet it won't make much
   *             difference if we are running VLANs.  The good news is that
   *             this protocol won't be in the list unless compiled in, so

   *             the average user (w/out VLANs) will not be adversely affected.

   *             --BLG
   *
   *		0800	IP
   *		8100    802.1Q VLAN
   *		0001	802.3
   *		0002	AX.25
   *		0004	802.2
   *		8035	RARP
   *		0005	SNAP
   *		0805	X.25
   *		0806	ARP
   *		8137	IPX
   *		0009	Localtalk
   *		86DD	IPv6
   */

  #define PTYPE_HASH_SIZE	(16)
  #define PTYPE_HASH_MASK	(PTYPE_HASH_SIZE - 1)

  static DEFINE_SPINLOCK(ptype_lock);

  static struct list_head ptype_base[PTYPE_HASH_SIZE] __read_mostly;

  static struct list_head ptype_all __read_mostly;	/* Taps */

  #ifdef CONFIG_NET_DMA

  struct net_dma {
  	struct dma_client client;
  	spinlock_t lock;
  	cpumask_t channel_mask;

  	struct dma_chan **channels;

  };
  
  static enum dma_state_client
  netdev_dma_event(struct dma_client *client, struct dma_chan *chan,
  	enum dma_state state);
  
  static struct net_dma net_dma = {
  	.client = {
  		.event_callback = netdev_dma_event,
  	},
  };

  #endif

  /*

   * The @dev_base_head list is protected by @dev_base_lock and the rtnl

   * semaphore.
   *
   * Pure readers hold dev_base_lock for reading.
   *
   * Writers must hold the rtnl semaphore while they loop through the

   * dev_base_head list, and hold dev_base_lock for writing when they do the

   * actual updates.  This allows pure readers to access the list even
   * while a writer is preparing to update it.
   *
   * To put it another way, dev_base_lock is held for writing only to
   * protect against pure readers; the rtnl semaphore provides the
   * protection against other writers.
   *
   * See, for example usages, register_netdevice() and
   * unregister_netdevice(), which must be called with the rtnl
   * semaphore held.
   */

  DEFINE_RWLOCK(dev_base_lock);

  EXPORT_SYMBOL(dev_base_lock);
  
  #define NETDEV_HASHBITS	8

  #define NETDEV_HASHENTRIES (1 << NETDEV_HASHBITS)

  static inline struct hlist_head *dev_name_hash(struct net *net, const char *name)

  {
  	unsigned hash = full_name_hash(name, strnlen(name, IFNAMSIZ));

  	return &net->dev_name_head[hash & ((1 << NETDEV_HASHBITS) - 1)];

  }

  static inline struct hlist_head *dev_index_hash(struct net *net, int ifindex)

  {

  	return &net->dev_index_head[ifindex & ((1 << NETDEV_HASHBITS) - 1)];

  }

  /* Device list insertion */
  static int list_netdevice(struct net_device *dev)
  {

  	struct net *net = dev_net(dev);

  
  	ASSERT_RTNL();
  
  	write_lock_bh(&dev_base_lock);
  	list_add_tail(&dev->dev_list, &net->dev_base_head);
  	hlist_add_head(&dev->name_hlist, dev_name_hash(net, dev->name));
  	hlist_add_head(&dev->index_hlist, dev_index_hash(net, dev->ifindex));
  	write_unlock_bh(&dev_base_lock);
  	return 0;
  }
  
  /* Device list removal */
  static void unlist_netdevice(struct net_device *dev)
  {
  	ASSERT_RTNL();
  
  	/* Unlink dev from the device chain */
  	write_lock_bh(&dev_base_lock);
  	list_del(&dev->dev_list);
  	hlist_del(&dev->name_hlist);
  	hlist_del(&dev->index_hlist);
  	write_unlock_bh(&dev_base_lock);
  }

  /*
   *	Our notifier list
   */

  static RAW_NOTIFIER_HEAD(netdev_chain);

  
  /*
   *	Device drivers call our routines to queue packets here. We empty the
   *	queue in the local softnet handler.
   */

  
  DEFINE_PER_CPU(struct softnet_data, softnet_data);

  #ifdef CONFIG_DEBUG_LOCK_ALLOC
  /*
   * register_netdevice() inits dev->_xmit_lock and sets lockdep class
   * according to dev->type
   */
  static const unsigned short netdev_lock_type[] =
  	{ARPHRD_NETROM, ARPHRD_ETHER, ARPHRD_EETHER, ARPHRD_AX25,
  	 ARPHRD_PRONET, ARPHRD_CHAOS, ARPHRD_IEEE802, ARPHRD_ARCNET,
  	 ARPHRD_APPLETLK, ARPHRD_DLCI, ARPHRD_ATM, ARPHRD_METRICOM,
  	 ARPHRD_IEEE1394, ARPHRD_EUI64, ARPHRD_INFINIBAND, ARPHRD_SLIP,
  	 ARPHRD_CSLIP, ARPHRD_SLIP6, ARPHRD_CSLIP6, ARPHRD_RSRVD,
  	 ARPHRD_ADAPT, ARPHRD_ROSE, ARPHRD_X25, ARPHRD_HWX25,
  	 ARPHRD_PPP, ARPHRD_CISCO, ARPHRD_LAPB, ARPHRD_DDCMP,
  	 ARPHRD_RAWHDLC, ARPHRD_TUNNEL, ARPHRD_TUNNEL6, ARPHRD_FRAD,
  	 ARPHRD_SKIP, ARPHRD_LOOPBACK, ARPHRD_LOCALTLK, ARPHRD_FDDI,
  	 ARPHRD_BIF, ARPHRD_SIT, ARPHRD_IPDDP, ARPHRD_IPGRE,
  	 ARPHRD_PIMREG, ARPHRD_HIPPI, ARPHRD_ASH, ARPHRD_ECONET,
  	 ARPHRD_IRDA, ARPHRD_FCPP, ARPHRD_FCAL, ARPHRD_FCPL,
  	 ARPHRD_FCFABRIC, ARPHRD_IEEE802_TR, ARPHRD_IEEE80211,
  	 ARPHRD_IEEE80211_PRISM, ARPHRD_IEEE80211_RADIOTAP, ARPHRD_VOID,
  	 ARPHRD_NONE};
  
  static const char *netdev_lock_name[] =
  	{"_xmit_NETROM", "_xmit_ETHER", "_xmit_EETHER", "_xmit_AX25",
  	 "_xmit_PRONET", "_xmit_CHAOS", "_xmit_IEEE802", "_xmit_ARCNET",
  	 "_xmit_APPLETLK", "_xmit_DLCI", "_xmit_ATM", "_xmit_METRICOM",
  	 "_xmit_IEEE1394", "_xmit_EUI64", "_xmit_INFINIBAND", "_xmit_SLIP",
  	 "_xmit_CSLIP", "_xmit_SLIP6", "_xmit_CSLIP6", "_xmit_RSRVD",
  	 "_xmit_ADAPT", "_xmit_ROSE", "_xmit_X25", "_xmit_HWX25",
  	 "_xmit_PPP", "_xmit_CISCO", "_xmit_LAPB", "_xmit_DDCMP",
  	 "_xmit_RAWHDLC", "_xmit_TUNNEL", "_xmit_TUNNEL6", "_xmit_FRAD",
  	 "_xmit_SKIP", "_xmit_LOOPBACK", "_xmit_LOCALTLK", "_xmit_FDDI",
  	 "_xmit_BIF", "_xmit_SIT", "_xmit_IPDDP", "_xmit_IPGRE",
  	 "_xmit_PIMREG", "_xmit_HIPPI", "_xmit_ASH", "_xmit_ECONET",
  	 "_xmit_IRDA", "_xmit_FCPP", "_xmit_FCAL", "_xmit_FCPL",
  	 "_xmit_FCFABRIC", "_xmit_IEEE802_TR", "_xmit_IEEE80211",
  	 "_xmit_IEEE80211_PRISM", "_xmit_IEEE80211_RADIOTAP", "_xmit_VOID",
  	 "_xmit_NONE"};
  
  static struct lock_class_key netdev_xmit_lock_key[ARRAY_SIZE(netdev_lock_type)];
  
  static inline unsigned short netdev_lock_pos(unsigned short dev_type)
  {
  	int i;
  
  	for (i = 0; i < ARRAY_SIZE(netdev_lock_type); i++)
  		if (netdev_lock_type[i] == dev_type)
  			return i;
  	/* the last key is used by default */
  	return ARRAY_SIZE(netdev_lock_type) - 1;
  }
  
  static inline void netdev_set_lockdep_class(spinlock_t *lock,
  					    unsigned short dev_type)
  {
  	int i;
  
  	i = netdev_lock_pos(dev_type);
  	lockdep_set_class_and_name(lock, &netdev_xmit_lock_key[i],
  				   netdev_lock_name[i]);
  }
  #else
  static inline void netdev_set_lockdep_class(spinlock_t *lock,
  					    unsigned short dev_type)
  {
  }
  #endif

  
  /*******************************************************************************
  
  		Protocol management and registration routines
  
  *******************************************************************************/
  
  /*

   *	Add a protocol ID to the list. Now that the input handler is
   *	smarter we can dispense with all the messy stuff that used to be
   *	here.
   *
   *	BEWARE!!! Protocol handlers, mangling input packets,
   *	MUST BE last in hash buckets and checking protocol handlers
   *	MUST start from promiscuous ptype_all chain in net_bh.
   *	It is true now, do not change it.
   *	Explanation follows: if protocol handler, mangling packet, will
   *	be the first on list, it is not able to sense, that packet
   *	is cloned and should be copied-on-write, so that it will
   *	change it and subsequent readers will get broken packet.
   *							--ANK (980803)
   */
  
  /**
   *	dev_add_pack - add packet handler
   *	@pt: packet type declaration
   *
   *	Add a protocol handler to the networking stack. The passed &packet_type
   *	is linked into kernel lists and may not be freed until it has been
   *	removed from the kernel lists.
   *

   *	This call does not sleep therefore it can not

   *	guarantee all CPU's that are in middle of receiving packets
   *	will see the new packet type (until the next received packet).
   */
  
  void dev_add_pack(struct packet_type *pt)
  {
  	int hash;
  
  	spin_lock_bh(&ptype_lock);

  	if (pt->type == htons(ETH_P_ALL))

  		list_add_rcu(&pt->list, &ptype_all);

  	else {

  		hash = ntohs(pt->type) & PTYPE_HASH_MASK;

  		list_add_rcu(&pt->list, &ptype_base[hash]);
  	}
  	spin_unlock_bh(&ptype_lock);
  }

  /**
   *	__dev_remove_pack	 - remove packet handler
   *	@pt: packet type declaration
   *
   *	Remove a protocol handler that was previously added to the kernel
   *	protocol handlers by dev_add_pack(). The passed &packet_type is removed
   *	from the kernel lists and can be freed or reused once this function

   *	returns.

   *
   *      The packet type might still be in use by receivers
   *	and must not be freed until after all the CPU's have gone
   *	through a quiescent state.
   */
  void __dev_remove_pack(struct packet_type *pt)
  {
  	struct list_head *head;
  	struct packet_type *pt1;
  
  	spin_lock_bh(&ptype_lock);

  	if (pt->type == htons(ETH_P_ALL))

  		head = &ptype_all;

  	else

  		head = &ptype_base[ntohs(pt->type) & PTYPE_HASH_MASK];

  
  	list_for_each_entry(pt1, head, list) {
  		if (pt == pt1) {
  			list_del_rcu(&pt->list);
  			goto out;
  		}
  	}
  
  	printk(KERN_WARNING "dev_remove_pack: %p not found.
  ", pt);
  out:
  	spin_unlock_bh(&ptype_lock);
  }
  /**
   *	dev_remove_pack	 - remove packet handler
   *	@pt: packet type declaration
   *
   *	Remove a protocol handler that was previously added to the kernel
   *	protocol handlers by dev_add_pack(). The passed &packet_type is removed
   *	from the kernel lists and can be freed or reused once this function
   *	returns.
   *
   *	This call sleeps to guarantee that no CPU is looking at the packet
   *	type after return.
   */
  void dev_remove_pack(struct packet_type *pt)
  {
  	__dev_remove_pack(pt);

  	synchronize_net();
  }
  
  /******************************************************************************
  
  		      Device Boot-time Settings Routines
  
  *******************************************************************************/
  
  /* Boot time configuration table */
  static struct netdev_boot_setup dev_boot_setup[NETDEV_BOOT_SETUP_MAX];
  
  /**
   *	netdev_boot_setup_add	- add new setup entry
   *	@name: name of the device
   *	@map: configured settings for the device
   *
   *	Adds new setup entry to the dev_boot_setup list.  The function
   *	returns 0 on error and 1 on success.  This is a generic routine to
   *	all netdevices.
   */
  static int netdev_boot_setup_add(char *name, struct ifmap *map)
  {
  	struct netdev_boot_setup *s;
  	int i;
  
  	s = dev_boot_setup;
  	for (i = 0; i < NETDEV_BOOT_SETUP_MAX; i++) {
  		if (s[i].name[0] == '\0' || s[i].name[0] == ' ') {
  			memset(s[i].name, 0, sizeof(s[i].name));
  			strcpy(s[i].name, name);
  			memcpy(&s[i].map, map, sizeof(s[i].map));
  			break;
  		}
  	}
  
  	return i >= NETDEV_BOOT_SETUP_MAX ? 0 : 1;
  }
  
  /**
   *	netdev_boot_setup_check	- check boot time settings
   *	@dev: the netdevice
   *
   * 	Check boot time settings for the device.
   *	The found settings are set for the device to be used
   *	later in the device probing.
   *	Returns 0 if no settings found, 1 if they are.
   */
  int netdev_boot_setup_check(struct net_device *dev)
  {
  	struct netdev_boot_setup *s = dev_boot_setup;
  	int i;
  
  	for (i = 0; i < NETDEV_BOOT_SETUP_MAX; i++) {
  		if (s[i].name[0] != '\0' && s[i].name[0] != ' ' &&
  		    !strncmp(dev->name, s[i].name, strlen(s[i].name))) {
  			dev->irq 	= s[i].map.irq;
  			dev->base_addr 	= s[i].map.base_addr;
  			dev->mem_start 	= s[i].map.mem_start;
  			dev->mem_end 	= s[i].map.mem_end;
  			return 1;
  		}
  	}
  	return 0;
  }
  
  
  /**
   *	netdev_boot_base	- get address from boot time settings
   *	@prefix: prefix for network device
   *	@unit: id for network device
   *
   * 	Check boot time settings for the base address of device.
   *	The found settings are set for the device to be used
   *	later in the device probing.
   *	Returns 0 if no settings found.
   */
  unsigned long netdev_boot_base(const char *prefix, int unit)
  {
  	const struct netdev_boot_setup *s = dev_boot_setup;
  	char name[IFNAMSIZ];
  	int i;
  
  	sprintf(name, "%s%d", prefix, unit);
  
  	/*
  	 * If device already registered then return base of 1
  	 * to indicate not to probe for this interface
  	 */

  	if (__dev_get_by_name(&init_net, name))

  		return 1;
  
  	for (i = 0; i < NETDEV_BOOT_SETUP_MAX; i++)
  		if (!strcmp(name, s[i].name))
  			return s[i].map.base_addr;
  	return 0;
  }
  
  /*
   * Saves at boot time configured settings for any netdevice.
   */
  int __init netdev_boot_setup(char *str)
  {
  	int ints[5];
  	struct ifmap map;
  
  	str = get_options(str, ARRAY_SIZE(ints), ints);
  	if (!str || !*str)
  		return 0;
  
  	/* Save settings */
  	memset(&map, 0, sizeof(map));
  	if (ints[0] > 0)
  		map.irq = ints[1];
  	if (ints[0] > 1)
  		map.base_addr = ints[2];
  	if (ints[0] > 2)
  		map.mem_start = ints[3];
  	if (ints[0] > 3)
  		map.mem_end = ints[4];
  
  	/* Add new entry to the list */
  	return netdev_boot_setup_add(str, &map);
  }
  
  __setup("netdev=", netdev_boot_setup);
  
  /*******************************************************************************
  
  			    Device Interface Subroutines
  
  *******************************************************************************/
  
  /**
   *	__dev_get_by_name	- find a device by its name

   *	@net: the applicable net namespace

   *	@name: name to find
   *
   *	Find an interface by name. Must be called under RTNL semaphore
   *	or @dev_base_lock. If the name is found a pointer to the device
   *	is returned. If the name is not found then %NULL is returned. The
   *	reference counters are not incremented so the caller must be
   *	careful with locks.
   */

  struct net_device *__dev_get_by_name(struct net *net, const char *name)

  {
  	struct hlist_node *p;

  	hlist_for_each(p, dev_name_hash(net, name)) {

  		struct net_device *dev
  			= hlist_entry(p, struct net_device, name_hlist);
  		if (!strncmp(dev->name, name, IFNAMSIZ))
  			return dev;
  	}
  	return NULL;
  }
  
  /**
   *	dev_get_by_name		- find a device by its name

   *	@net: the applicable net namespace

   *	@name: name to find
   *
   *	Find an interface by name. This can be called from any
   *	context and does its own locking. The returned handle has
   *	the usage count incremented and the caller must use dev_put() to
   *	release it when it is no longer needed. %NULL is returned if no
   *	matching device is found.
   */

  struct net_device *dev_get_by_name(struct net *net, const char *name)

  {
  	struct net_device *dev;
  
  	read_lock(&dev_base_lock);

  	dev = __dev_get_by_name(net, name);

  	if (dev)
  		dev_hold(dev);
  	read_unlock(&dev_base_lock);
  	return dev;
  }
  
  /**
   *	__dev_get_by_index - find a device by its ifindex

   *	@net: the applicable net namespace

   *	@ifindex: index of device
   *
   *	Search for an interface by index. Returns %NULL if the device
   *	is not found or a pointer to the device. The device has not
   *	had its reference counter increased so the caller must be careful
   *	about locking. The caller must hold either the RTNL semaphore
   *	or @dev_base_lock.
   */

  struct net_device *__dev_get_by_index(struct net *net, int ifindex)

  {
  	struct hlist_node *p;

  	hlist_for_each(p, dev_index_hash(net, ifindex)) {

  		struct net_device *dev
  			= hlist_entry(p, struct net_device, index_hlist);
  		if (dev->ifindex == ifindex)
  			return dev;
  	}
  	return NULL;
  }
  
  
  /**
   *	dev_get_by_index - find a device by its ifindex

   *	@net: the applicable net namespace

   *	@ifindex: index of device
   *
   *	Search for an interface by index. Returns NULL if the device
   *	is not found or a pointer to the device. The device returned has
   *	had a reference added and the pointer is safe until the user calls
   *	dev_put to indicate they have finished with it.
   */

  struct net_device *dev_get_by_index(struct net *net, int ifindex)

  {
  	struct net_device *dev;
  
  	read_lock(&dev_base_lock);

  	dev = __dev_get_by_index(net, ifindex);

  	if (dev)
  		dev_hold(dev);
  	read_unlock(&dev_base_lock);
  	return dev;
  }
  
  /**
   *	dev_getbyhwaddr - find a device by its hardware address

   *	@net: the applicable net namespace

   *	@type: media type of device
   *	@ha: hardware address
   *
   *	Search for an interface by MAC address. Returns NULL if the device
   *	is not found or a pointer to the device. The caller must hold the
   *	rtnl semaphore. The returned device has not had its ref count increased
   *	and the caller must therefore be careful about locking
   *
   *	BUGS:
   *	If the API was consistent this would be __dev_get_by_hwaddr
   */

  struct net_device *dev_getbyhwaddr(struct net *net, unsigned short type, char *ha)

  {
  	struct net_device *dev;
  
  	ASSERT_RTNL();

  	for_each_netdev(net, dev)

  		if (dev->type == type &&
  		    !memcmp(dev->dev_addr, ha, dev->addr_len))

  			return dev;
  
  	return NULL;

  }

  EXPORT_SYMBOL(dev_getbyhwaddr);

  struct net_device *__dev_getfirstbyhwtype(struct net *net, unsigned short type)

  {
  	struct net_device *dev;

  	ASSERT_RTNL();

  	for_each_netdev(net, dev)

  		if (dev->type == type)

  			return dev;
  
  	return NULL;

  }
  
  EXPORT_SYMBOL(__dev_getfirstbyhwtype);

  struct net_device *dev_getfirstbyhwtype(struct net *net, unsigned short type)

  {
  	struct net_device *dev;
  
  	rtnl_lock();

  	dev = __dev_getfirstbyhwtype(net, type);

  	if (dev)
  		dev_hold(dev);

  	rtnl_unlock();
  	return dev;
  }
  
  EXPORT_SYMBOL(dev_getfirstbyhwtype);
  
  /**
   *	dev_get_by_flags - find any device with given flags

   *	@net: the applicable net namespace

   *	@if_flags: IFF_* values
   *	@mask: bitmask of bits in if_flags to check
   *
   *	Search for any interface with the given flags. Returns NULL if a device

   *	is not found or a pointer to the device. The device returned has

   *	had a reference added and the pointer is safe until the user calls
   *	dev_put to indicate they have finished with it.
   */

  struct net_device * dev_get_by_flags(struct net *net, unsigned short if_flags, unsigned short mask)

  {

  	struct net_device *dev, *ret;

  	ret = NULL;

  	read_lock(&dev_base_lock);

  	for_each_netdev(net, dev) {

  		if (((dev->flags ^ if_flags) & mask) == 0) {
  			dev_hold(dev);

  			ret = dev;

  			break;
  		}
  	}
  	read_unlock(&dev_base_lock);

  	return ret;

  }
  
  /**
   *	dev_valid_name - check if name is okay for network device
   *	@name: name string
   *
   *	Network device names need to be valid file names to

   *	to allow sysfs to work.  We also disallow any kind of
   *	whitespace.

   */

  int dev_valid_name(const char *name)

  {

  	if (*name == '\0')
  		return 0;

  	if (strlen(name) >= IFNAMSIZ)
  		return 0;

  	if (!strcmp(name, ".") || !strcmp(name, ".."))
  		return 0;
  
  	while (*name) {
  		if (*name == '/' || isspace(*name))
  			return 0;
  		name++;
  	}
  	return 1;

  }
  
  /**

   *	__dev_alloc_name - allocate a name for a device
   *	@net: network namespace to allocate the device name in

   *	@name: name format string

   *	@buf:  scratch buffer and result name string

   *
   *	Passed a format string - eg "lt%d" it will try and find a suitable

   *	id. It scans list of devices to build up a free map, then chooses
   *	the first empty slot. The caller must hold the dev_base or rtnl lock
   *	while allocating the name and adding the device in order to avoid
   *	duplicates.
   *	Limited to bits_per_byte * page size devices (ie 32K on most platforms).
   *	Returns the number of the unit assigned or a negative errno code.

   */

  static int __dev_alloc_name(struct net *net, const char *name, char *buf)

  {
  	int i = 0;

  	const char *p;
  	const int max_netdevices = 8*PAGE_SIZE;

  	unsigned long *inuse;

  	struct net_device *d;
  
  	p = strnchr(name, IFNAMSIZ-1, '%');
  	if (p) {
  		/*
  		 * Verify the string as this thing may have come from
  		 * the user.  There must be either one "%d" and no other "%"
  		 * characters.
  		 */
  		if (p[1] != 'd' || strchr(p + 2, '%'))
  			return -EINVAL;
  
  		/* Use one page as a bit array of possible slots */

  		inuse = (unsigned long *) get_zeroed_page(GFP_ATOMIC);

  		if (!inuse)
  			return -ENOMEM;

  		for_each_netdev(net, d) {

  			if (!sscanf(d->name, name, &i))
  				continue;
  			if (i < 0 || i >= max_netdevices)
  				continue;
  
  			/*  avoid cases where sscanf is not exact inverse of printf */

  			snprintf(buf, IFNAMSIZ, name, i);

  			if (!strncmp(buf, d->name, IFNAMSIZ))
  				set_bit(i, inuse);
  		}
  
  		i = find_first_zero_bit(inuse, max_netdevices);
  		free_page((unsigned long) inuse);
  	}

  	snprintf(buf, IFNAMSIZ, name, i);
  	if (!__dev_get_by_name(net, buf))

  		return i;

  
  	/* It is possible to run out of possible slots
  	 * when the name is long and there isn't enough space left
  	 * for the digits, or if all bits are used.
  	 */
  	return -ENFILE;
  }

  /**
   *	dev_alloc_name - allocate a name for a device
   *	@dev: device
   *	@name: name format string
   *
   *	Passed a format string - eg "lt%d" it will try and find a suitable
   *	id. It scans list of devices to build up a free map, then chooses
   *	the first empty slot. The caller must hold the dev_base or rtnl lock
   *	while allocating the name and adding the device in order to avoid
   *	duplicates.
   *	Limited to bits_per_byte * page size devices (ie 32K on most platforms).
   *	Returns the number of the unit assigned or a negative errno code.
   */
  
  int dev_alloc_name(struct net_device *dev, const char *name)
  {
  	char buf[IFNAMSIZ];
  	struct net *net;
  	int ret;

  	BUG_ON(!dev_net(dev));
  	net = dev_net(dev);

  	ret = __dev_alloc_name(net, name, buf);
  	if (ret >= 0)
  		strlcpy(dev->name, buf, IFNAMSIZ);
  	return ret;
  }

  
  /**
   *	dev_change_name - change name of a device
   *	@dev: device
   *	@newname: name (or format string) must be at least IFNAMSIZ
   *
   *	Change name of a device, can pass format strings "eth%d".
   *	for wildcarding.
   */
  int dev_change_name(struct net_device *dev, char *newname)
  {

  	char oldname[IFNAMSIZ];

  	int err = 0;

  	int ret;

  	struct net *net;

  
  	ASSERT_RTNL();

  	BUG_ON(!dev_net(dev));

  	net = dev_net(dev);

  	if (dev->flags & IFF_UP)
  		return -EBUSY;
  
  	if (!dev_valid_name(newname))
  		return -EINVAL;

  	if (strncmp(newname, dev->name, IFNAMSIZ) == 0)
  		return 0;

  	memcpy(oldname, dev->name, IFNAMSIZ);

  	if (strchr(newname, '%')) {
  		err = dev_alloc_name(dev, newname);
  		if (err < 0)
  			return err;
  		strcpy(newname, dev->name);
  	}

  	else if (__dev_get_by_name(net, newname))

  		return -EEXIST;
  	else
  		strlcpy(dev->name, newname, IFNAMSIZ);

  rollback:

  	err = device_rename(&dev->dev, dev->name);
  	if (err) {
  		memcpy(dev->name, oldname, IFNAMSIZ);
  		return err;
  	}

  
  	write_lock_bh(&dev_base_lock);

  	hlist_del(&dev->name_hlist);

  	hlist_add_head(&dev->name_hlist, dev_name_hash(net, dev->name));

  	write_unlock_bh(&dev_base_lock);

  	ret = call_netdevice_notifiers(NETDEV_CHANGENAME, dev);

  	ret = notifier_to_errno(ret);
  
  	if (ret) {
  		if (err) {
  			printk(KERN_ERR
  			       "%s: name change rollback failed: %d.
  ",
  			       dev->name, ret);
  		} else {
  			err = ret;
  			memcpy(dev->name, oldname, IFNAMSIZ);
  			goto rollback;
  		}
  	}

  
  	return err;
  }
  
  /**

   *	netdev_features_change - device changes features

   *	@dev: device to cause notification
   *
   *	Called to indicate a device has changed features.
   */
  void netdev_features_change(struct net_device *dev)
  {

  	call_netdevice_notifiers(NETDEV_FEAT_CHANGE, dev);

  }
  EXPORT_SYMBOL(netdev_features_change);
  
  /**

   *	netdev_state_change - device changes state
   *	@dev: device to cause notification
   *
   *	Called to indicate a device has changed state. This function calls
   *	the notifier chains for netdev_chain and sends a NEWLINK message
   *	to the routing socket.
   */
  void netdev_state_change(struct net_device *dev)
  {
  	if (dev->flags & IFF_UP) {

  		call_netdevice_notifiers(NETDEV_CHANGE, dev);

  		rtmsg_ifinfo(RTM_NEWLINK, dev, 0);
  	}
  }
  
  /**
   *	dev_load 	- load a network module

   *	@net: the applicable net namespace

   *	@name: name of interface
   *
   *	If a network interface is not present and the process has suitable
   *	privileges this function loads the module. If module loading is not
   *	available in this kernel then it becomes a nop.
   */

  void dev_load(struct net *net, const char *name)

  {

  	struct net_device *dev;

  
  	read_lock(&dev_base_lock);

  	dev = __dev_get_by_name(net, name);

  	read_unlock(&dev_base_lock);
  
  	if (!dev && capable(CAP_SYS_MODULE))
  		request_module("%s", name);
  }

  /**
   *	dev_open	- prepare an interface for use.
   *	@dev:	device to open
   *
   *	Takes a device from down to up state. The device's private open
   *	function is invoked and then the multicast lists are loaded. Finally
   *	the device is moved into the up state and a %NETDEV_UP message is
   *	sent to the netdev notifier chain.
   *
   *	Calling this function on an active interface is a nop. On a failure
   *	a negative errno code is returned.
   */
  int dev_open(struct net_device *dev)
  {
  	int ret = 0;

  	ASSERT_RTNL();

  	/*
  	 *	Is it already up?
  	 */
  
  	if (dev->flags & IFF_UP)
  		return 0;
  
  	/*
  	 *	Is it even present?
  	 */
  	if (!netif_device_present(dev))
  		return -ENODEV;
  
  	/*
  	 *	Call device private open method
  	 */
  	set_bit(__LINK_STATE_START, &dev->state);

  
  	if (dev->validate_addr)
  		ret = dev->validate_addr(dev);
  
  	if (!ret && dev->open)

  		ret = dev->open(dev);

  	/*

  	 *	If it went open OK then:
  	 */

  	if (ret)
  		clear_bit(__LINK_STATE_START, &dev->state);
  	else {

  		/*
  		 *	Set the flags.
  		 */
  		dev->flags |= IFF_UP;
  
  		/*
  		 *	Initialize multicasting status
  		 */

  		dev_set_rx_mode(dev);

  
  		/*
  		 *	Wakeup transmit queue engine
  		 */
  		dev_activate(dev);
  
  		/*
  		 *	... and announce new interface.
  		 */

  		call_netdevice_notifiers(NETDEV_UP, dev);

  	}

  	return ret;
  }
  
  /**
   *	dev_close - shutdown an interface.
   *	@dev: device to shutdown
   *
   *	This function moves an active device into down state. A
   *	%NETDEV_GOING_DOWN is sent to the netdev notifier chain. The device
   *	is then deactivated and finally a %NETDEV_DOWN is sent to the notifier
   *	chain.
   */
  int dev_close(struct net_device *dev)
  {

  	ASSERT_RTNL();

  	might_sleep();

  	if (!(dev->flags & IFF_UP))
  		return 0;
  
  	/*
  	 *	Tell people we are going down, so that they can
  	 *	prepare to death, when device is still operating.
  	 */

  	call_netdevice_notifiers(NETDEV_GOING_DOWN, dev);

  	clear_bit(__LINK_STATE_START, &dev->state);
  
  	/* Synchronize to scheduled poll. We cannot touch poll list,

  	 * it can be even on different cpu. So just clear netif_running().
  	 *
  	 * dev->stop() will invoke napi_disable() on all of it's
  	 * napi_struct instances on this device.
  	 */

  	smp_mb__after_clear_bit(); /* Commit netif_running(). */

  	dev_deactivate(dev);

  	/*
  	 *	Call the device specific close. This cannot fail.
  	 *	Only if device is UP
  	 *
  	 *	We allow it to be called even after a DETACH hot-plug
  	 *	event.
  	 */
  	if (dev->stop)
  		dev->stop(dev);
  
  	/*
  	 *	Device is now down.
  	 */
  
  	dev->flags &= ~IFF_UP;
  
  	/*
  	 * Tell people we are down
  	 */

  	call_netdevice_notifiers(NETDEV_DOWN, dev);

  
  	return 0;
  }

  static int dev_boot_phase = 1;

  /*
   *	Device change register/unregister. These are not inline or static
   *	as we export them to the world.
   */
  
  /**
   *	register_netdevice_notifier - register a network notifier block
   *	@nb: notifier
   *
   *	Register a notifier to be called when network device events occur.
   *	The notifier passed is linked into the kernel structures and must
   *	not be reused until it has been unregistered. A negative errno code
   *	is returned on a failure.
   *
   * 	When registered all registration and up events are replayed

   *	to the new notifier to allow device to have a race free

   *	view of the network device list.
   */
  
  int register_netdevice_notifier(struct notifier_block *nb)
  {
  	struct net_device *dev;

  	struct net_device *last;

  	struct net *net;

  	int err;
  
  	rtnl_lock();

  	err = raw_notifier_chain_register(&netdev_chain, nb);

  	if (err)
  		goto unlock;

  	if (dev_boot_phase)
  		goto unlock;
  	for_each_net(net) {
  		for_each_netdev(net, dev) {
  			err = nb->notifier_call(nb, NETDEV_REGISTER, dev);
  			err = notifier_to_errno(err);
  			if (err)
  				goto rollback;
  
  			if (!(dev->flags & IFF_UP))
  				continue;

  			nb->notifier_call(nb, NETDEV_UP, dev);
  		}

  	}

  
  unlock:

  	rtnl_unlock();
  	return err;

  
  rollback:
  	last = dev;

  	for_each_net(net) {
  		for_each_netdev(net, dev) {
  			if (dev == last)
  				break;

  			if (dev->flags & IFF_UP) {
  				nb->notifier_call(nb, NETDEV_GOING_DOWN, dev);
  				nb->notifier_call(nb, NETDEV_DOWN, dev);
  			}
  			nb->notifier_call(nb, NETDEV_UNREGISTER, dev);

  		}

  	}

  
  	raw_notifier_chain_unregister(&netdev_chain, nb);

  	goto unlock;

  }
  
  /**
   *	unregister_netdevice_notifier - unregister a network notifier block
   *	@nb: notifier
   *
   *	Unregister a notifier previously registered by
   *	register_netdevice_notifier(). The notifier is unlinked into the
   *	kernel structures and may then be reused. A negative errno code
   *	is returned on a failure.
   */
  
  int unregister_netdevice_notifier(struct notifier_block *nb)
  {

  	int err;
  
  	rtnl_lock();

  	err = raw_notifier_chain_unregister(&netdev_chain, nb);

  	rtnl_unlock();
  	return err;

  }
  
  /**
   *	call_netdevice_notifiers - call all network notifier blocks
   *      @val: value passed unmodified to notifier function

   *      @dev: net_device pointer passed unmodified to notifier function

   *
   *	Call all network notifier blocks.  Parameters and return value

   *	are as for raw_notifier_call_chain().

   */

  int call_netdevice_notifiers(unsigned long val, struct net_device *dev)

  {

  	return raw_notifier_call_chain(&netdev_chain, val, dev);

  }
  
  /* When > 0 there are consumers of rx skb time stamps */
  static atomic_t netstamp_needed = ATOMIC_INIT(0);
  
  void net_enable_timestamp(void)
  {
  	atomic_inc(&netstamp_needed);
  }
  
  void net_disable_timestamp(void)
  {
  	atomic_dec(&netstamp_needed);
  }

  static inline void net_timestamp(struct sk_buff *skb)

  {
  	if (atomic_read(&netstamp_needed))

  		__net_timestamp(skb);

  	else
  		skb->tstamp.tv64 = 0;

  }
  
  /*
   *	Support routine. Sends outgoing frames to any network
   *	taps currently in use.
   */

  static void dev_queue_xmit_nit(struct sk_buff *skb, struct net_device *dev)

  {
  	struct packet_type *ptype;

  
  	net_timestamp(skb);

  
  	rcu_read_lock();
  	list_for_each_entry_rcu(ptype, &ptype_all, list) {
  		/* Never send packets back to the socket
  		 * they originated from - MvS (miquels@drinkel.ow.org)
  		 */
  		if ((ptype->dev == dev || !ptype->dev) &&
  		    (ptype->af_packet_priv == NULL ||
  		     (struct sock *)ptype->af_packet_priv != skb->sk)) {
  			struct sk_buff *skb2= skb_clone(skb, GFP_ATOMIC);
  			if (!skb2)
  				break;
  
  			/* skb->nh should be correctly
  			   set by sender, so that the second statement is
  			   just protection against buggy protocols.
  			 */

  			skb_reset_mac_header(skb2);

  			if (skb_network_header(skb2) < skb2->data ||

  			    skb2->network_header > skb2->tail) {

  				if (net_ratelimit())
  					printk(KERN_CRIT "protocol %04x is "
  					       "buggy, dev %s
  ",
  					       skb2->protocol, dev->name);

  				skb_reset_network_header(skb2);

  			}

  			skb2->transport_header = skb2->network_header;

  			skb2->pkt_type = PACKET_OUTGOING;

  			ptype->func(skb2, skb->dev, ptype, skb->dev);

  		}
  	}
  	rcu_read_unlock();
  }

  
  void __netif_schedule(struct net_device *dev)
  {
  	if (!test_and_set_bit(__LINK_STATE_SCHED, &dev->state)) {
  		unsigned long flags;
  		struct softnet_data *sd;
  
  		local_irq_save(flags);
  		sd = &__get_cpu_var(softnet_data);
  		dev->next_sched = sd->output_queue;
  		sd->output_queue = dev;
  		raise_softirq_irqoff(NET_TX_SOFTIRQ);
  		local_irq_restore(flags);
  	}
  }
  EXPORT_SYMBOL(__netif_schedule);

  void dev_kfree_skb_irq(struct sk_buff *skb)

  {

  	if (atomic_dec_and_test(&skb->users)) {
  		struct softnet_data *sd;
  		unsigned long flags;

  		local_irq_save(flags);
  		sd = &__get_cpu_var(softnet_data);
  		skb->next = sd->completion_queue;
  		sd->completion_queue = skb;
  		raise_softirq_irqoff(NET_TX_SOFTIRQ);
  		local_irq_restore(flags);
  	}

  }

  EXPORT_SYMBOL(dev_kfree_skb_irq);

  
  void dev_kfree_skb_any(struct sk_buff *skb)
  {
  	if (in_irq() || irqs_disabled())
  		dev_kfree_skb_irq(skb);
  	else
  		dev_kfree_skb(skb);
  }
  EXPORT_SYMBOL(dev_kfree_skb_any);

  /**
   * netif_device_detach - mark device as removed
   * @dev: network device
   *
   * Mark device as removed from system and therefore no longer available.
   */

  void netif_device_detach(struct net_device *dev)
  {
  	if (test_and_clear_bit(__LINK_STATE_PRESENT, &dev->state) &&
  	    netif_running(dev)) {
  		netif_stop_queue(dev);
  	}
  }
  EXPORT_SYMBOL(netif_device_detach);

  /**
   * netif_device_attach - mark device as attached
   * @dev: network device
   *
   * Mark device as attached from system and restart if needed.
   */

  void netif_device_attach(struct net_device *dev)
  {
  	if (!test_and_set_bit(__LINK_STATE_PRESENT, &dev->state) &&
  	    netif_running(dev)) {
  		netif_wake_queue(dev);

  		__netdev_watchdog_up(dev);

  	}
  }
  EXPORT_SYMBOL(netif_device_attach);

  static bool can_checksum_protocol(unsigned long features, __be16 protocol)
  {
  	return ((features & NETIF_F_GEN_CSUM) ||
  		((features & NETIF_F_IP_CSUM) &&
  		 protocol == htons(ETH_P_IP)) ||
  		((features & NETIF_F_IPV6_CSUM) &&
  		 protocol == htons(ETH_P_IPV6)));
  }
  
  static bool dev_can_checksum(struct net_device *dev, struct sk_buff *skb)
  {
  	if (can_checksum_protocol(dev->features, skb->protocol))
  		return true;
  
  	if (skb->protocol == htons(ETH_P_8021Q)) {
  		struct vlan_ethhdr *veh = (struct vlan_ethhdr *)skb->data;
  		if (can_checksum_protocol(dev->features & dev->vlan_features,
  					  veh->h_vlan_encapsulated_proto))
  			return true;
  	}
  
  	return false;
  }

  /*
   * Invalidate hardware checksum when packet is to be mangled, and
   * complete checksum manually on outgoing path.
   */

  int skb_checksum_help(struct sk_buff *skb)

  {

  	__wsum csum;

  	int ret = 0, offset;

  	if (skb->ip_summed == CHECKSUM_COMPLETE)

  		goto out_set_summed;
  
  	if (unlikely(skb_shinfo(skb)->gso_size)) {

  		/* Let GSO fix up the checksum. */
  		goto out_set_summed;

  	}

  	offset = skb->csum_start - skb_headroom(skb);
  	BUG_ON(offset >= skb_headlen(skb));
  	csum = skb_checksum(skb, offset, skb->len - offset, 0);
  
  	offset += skb->csum_offset;
  	BUG_ON(offset + sizeof(__sum16) > skb_headlen(skb));
  
  	if (skb_cloned(skb) &&
  	    !skb_clone_writable(skb, offset + sizeof(__sum16))) {

  		ret = pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
  		if (ret)
  			goto out;
  	}

  	*(__sum16 *)(skb->data + offset) = csum_fold(csum);

  out_set_summed:

  	skb->ip_summed = CHECKSUM_NONE;

  out:

  	return ret;
  }

  /**
   *	skb_gso_segment - Perform segmentation on skb.
   *	@skb: buffer to segment

   *	@features: features for the output path (see dev->features)

   *
   *	This function segments the given skb and returns a list of segments.

   *
   *	It may return NULL if the skb requires no segmentation.  This is
   *	only possible when GSO is used for verifying header integrity.

   */

  struct sk_buff *skb_gso_segment(struct sk_buff *skb, int features)

  {
  	struct sk_buff *segs = ERR_PTR(-EPROTONOSUPPORT);
  	struct packet_type *ptype;

  	__be16 type = skb->protocol;

  	int err;

  
  	BUG_ON(skb_shinfo(skb)->frag_list);

  	skb_reset_mac_header(skb);

  	skb->mac_len = skb->network_header - skb->mac_header;

  	__skb_pull(skb, skb->mac_len);

  	if (WARN_ON(skb->ip_summed != CHECKSUM_PARTIAL)) {

  		if (skb_header_cloned(skb) &&
  		    (err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
  			return ERR_PTR(err);
  	}

  	rcu_read_lock();

  	list_for_each_entry_rcu(ptype,
  			&ptype_base[ntohs(type) & PTYPE_HASH_MASK], list) {

  		if (ptype->type == type && !ptype->dev && ptype->gso_segment) {

  			if (unlikely(skb->ip_summed != CHECKSUM_PARTIAL)) {

  				err = ptype->gso_send_check(skb);
  				segs = ERR_PTR(err);
  				if (err || skb_gso_ok(skb, features))
  					break;

  				__skb_push(skb, (skb->data -
  						 skb_network_header(skb)));

  			}

  			segs = ptype->gso_segment(skb, features);

  			break;
  		}
  	}
  	rcu_read_unlock();

  	__skb_push(skb, skb->data - skb_mac_header(skb));

  	return segs;
  }
  
  EXPORT_SYMBOL(skb_gso_segment);

  /* Take action when hardware reception checksum errors are detected. */
  #ifdef CONFIG_BUG
  void netdev_rx_csum_fault(struct net_device *dev)
  {
  	if (net_ratelimit()) {

  		printk(KERN_ERR "%s: hw csum failure.
  ",

  			dev ? dev->name : "<unknown>");

  		dump_stack();
  	}
  }
  EXPORT_SYMBOL(netdev_rx_csum_fault);
  #endif

  /* Actually, we should eliminate this check as soon as we know, that:
   * 1. IOMMU is present and allows to map all the memory.
   * 2. No high memory really exists on this machine.
   */
  
  static inline int illegal_highdma(struct net_device *dev, struct sk_buff *skb)
  {

  #ifdef CONFIG_HIGHMEM

  	int i;
  
  	if (dev->features & NETIF_F_HIGHDMA)
  		return 0;
  
  	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
  		if (PageHighMem(skb_shinfo(skb)->frags[i].page))
  			return 1;

  #endif

  	return 0;
  }

  struct dev_gso_cb {
  	void (*destructor)(struct sk_buff *skb);
  };
  
  #define DEV_GSO_CB(skb) ((struct dev_gso_cb *)(skb)->cb)
  
  static void dev_gso_skb_destructor(struct sk_buff *skb)
  {
  	struct dev_gso_cb *cb;
  
  	do {
  		struct sk_buff *nskb = skb->next;
  
  		skb->next = nskb->next;
  		nskb->next = NULL;
  		kfree_skb(nskb);
  	} while (skb->next);
  
  	cb = DEV_GSO_CB(skb);
  	if (cb->destructor)
  		cb->destructor(skb);
  }
  
  /**
   *	dev_gso_segment - Perform emulated hardware segmentation on skb.
   *	@skb: buffer to segment
   *
   *	This function segments the given skb and stores the list of segments
   *	in skb->next.
   */
  static int dev_gso_segment(struct sk_buff *skb)
  {
  	struct net_device *dev = skb->dev;
  	struct sk_buff *segs;

  	int features = dev->features & ~(illegal_highdma(dev, skb) ?
  					 NETIF_F_SG : 0);
  
  	segs = skb_gso_segment(skb, features);
  
  	/* Verifying header integrity only. */
  	if (!segs)
  		return 0;

  	if (IS_ERR(segs))

  		return PTR_ERR(segs);
  
  	skb->next = segs;
  	DEV_GSO_CB(skb)->destructor = skb->destructor;
  	skb->destructor = dev_gso_skb_destructor;
  
  	return 0;
  }
  
  int dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev)
  {
  	if (likely(!skb->next)) {

  		if (!list_empty(&ptype_all))

  			dev_queue_xmit_nit(skb, dev);

  		if (netif_needs_gso(dev, skb)) {
  			if (unlikely(dev_gso_segment(skb)))
  				goto out_kfree_skb;
  			if (skb->next)
  				goto gso;
  		}

  		return dev->hard_start_xmit(skb, dev);

  	}

  gso:

  	do {
  		struct sk_buff *nskb = skb->next;
  		int rc;
  
  		skb->next = nskb->next;
  		nskb->next = NULL;
  		rc = dev->hard_start_xmit(nskb, dev);
  		if (unlikely(rc)) {

  			nskb->next = skb->next;

  			skb->next = nskb;
  			return rc;
  		}

  		if (unlikely((netif_queue_stopped(dev) ||

  			     netif_subqueue_stopped(dev, skb)) &&

  			     skb->next))

  			return NETDEV_TX_BUSY;

  	} while (skb->next);

  	skb->destructor = DEV_GSO_CB(skb)->destructor;
  
  out_kfree_skb:
  	kfree_skb(skb);
  	return 0;
  }

  /**
   *	dev_queue_xmit - transmit a buffer
   *	@skb: buffer to transmit
   *
   *	Queue a buffer for transmission to a network device. The caller must
   *	have set the device and priority and built the buffer before calling
   *	this function. The function can be called from an interrupt.
   *
   *	A negative errno code is returned on a failure. A success does not
   *	guarantee the frame will be transmitted as it may be dropped due
   *	to congestion or traffic shaping.

   *
   * -----------------------------------------------------------------------------------
   *      I notice this method can also return errors from the queue disciplines,
   *      including NET_XMIT_DROP, which is a positive value.  So, errors can also
   *      be positive.
   *
   *      Regardless of the return value, the skb is consumed, so it is currently
   *      difficult to retry a send to this method.  (You can bump the ref count
   *      before sending to hold a reference for retry if you are careful.)
   *
   *      When calling this method, interrupts MUST be enabled.  This is because
   *      the BH enable code must have IRQs enabled so that it will not deadlock.
   *          --BLG

   */
  
  int dev_queue_xmit(struct sk_buff *skb)
  {
  	struct net_device *dev = skb->dev;
  	struct Qdisc *q;
  	int rc = -ENOMEM;

  	/* GSO will handle the following emulations directly. */
  	if (netif_needs_gso(dev, skb))
  		goto gso;

  	if (skb_shinfo(skb)->frag_list &&
  	    !(dev->features & NETIF_F_FRAGLIST) &&

  	    __skb_linearize(skb))

  		goto out_kfree_skb;
  
  	/* Fragmented skb is linearized if device does not support SG,
  	 * or if at least one of fragments is in highmem and device
  	 * does not support DMA from it.
  	 */
  	if (skb_shinfo(skb)->nr_frags &&
  	    (!(dev->features & NETIF_F_SG) || illegal_highdma(dev, skb)) &&

  	    __skb_linearize(skb))

  		goto out_kfree_skb;
  
  	/* If packet is not checksummed and device does not support
  	 * checksumming for this protocol, complete checksumming here.
  	 */

  	if (skb->ip_summed == CHECKSUM_PARTIAL) {
  		skb_set_transport_header(skb, skb->csum_start -
  					      skb_headroom(skb));

  		if (!dev_can_checksum(dev, skb) && skb_checksum_help(skb))
  			goto out_kfree_skb;

  	}

  gso:

  	spin_lock_prefetch(&dev->queue_lock);

  	/* Disable soft irqs for various locks below. Also
  	 * stops preemption for RCU.

  	 */

  	rcu_read_lock_bh();

  	/* Updates of qdisc are serialized by queue_lock.
  	 * The struct Qdisc which is pointed to by qdisc is now a
  	 * rcu structure - it may be accessed without acquiring

  	 * a lock (but the structure may be stale.) The freeing of the

  	 * qdisc will be deferred until it's known that there are no

  	 * more references to it.

  	 *
  	 * If the qdisc has an enqueue function, we still need to

  	 * hold the queue_lock before calling it, since queue_lock
  	 * also serializes access to the device queue.
  	 */
  
  	q = rcu_dereference(dev->qdisc);
  #ifdef CONFIG_NET_CLS_ACT
  	skb->tc_verd = SET_TC_AT(skb->tc_verd,AT_EGRESS);
  #endif
  	if (q->enqueue) {
  		/* Grab device queue */
  		spin_lock(&dev->queue_lock);

  		q = dev->qdisc;
  		if (q->enqueue) {

  			/* reset queue_mapping to zero */

  			skb_set_queue_mapping(skb, 0);

  			rc = q->enqueue(skb, q);
  			qdisc_run(dev);
  			spin_unlock(&dev->queue_lock);

  			rc = rc == NET_XMIT_BYPASS ? NET_XMIT_SUCCESS : rc;
  			goto out;
  		}

  		spin_unlock(&dev->queue_lock);

  	}
  
  	/* The device has no queue. Common case for software devices:
  	   loopback, all the sorts of tunnels...

  	   Really, it is unlikely that netif_tx_lock protection is necessary
  	   here.  (f.e. loopback and IP tunnels are clean ignoring statistics

  	   counters.)
  	   However, it is possible, that they rely on protection
  	   made by us here.
  
  	   Check this and shot the lock. It is not prone from deadlocks.
  	   Either shot noqueue qdisc, it is even simpler 8)
  	 */
  	if (dev->flags & IFF_UP) {
  		int cpu = smp_processor_id(); /* ok because BHs are off */
  
  		if (dev->xmit_lock_owner != cpu) {
  
  			HARD_TX_LOCK(dev, cpu);

  			if (!netif_queue_stopped(dev) &&

  			    !netif_subqueue_stopped(dev, skb)) {

  				rc = 0;

  				if (!dev_hard_start_xmit(skb, dev)) {

  					HARD_TX_UNLOCK(dev);
  					goto out;
  				}
  			}
  			HARD_TX_UNLOCK(dev);
  			if (net_ratelimit())
  				printk(KERN_CRIT "Virtual device %s asks to "
  				       "queue packet!
  ", dev->name);
  		} else {
  			/* Recursion is detected! It is possible,
  			 * unfortunately */
  			if (net_ratelimit())
  				printk(KERN_CRIT "Dead loop on virtual device "
  				       "%s, fix it urgently!
  ", dev->name);
  		}
  	}
  
  	rc = -ENETDOWN;

  	rcu_read_unlock_bh();

  
  out_kfree_skb:
  	kfree_skb(skb);
  	return rc;
  out:

  	rcu_read_unlock_bh();

  	return rc;
  }
  
  
  /*=======================================================================
  			Receiver routines
    =======================================================================*/

  int netdev_max_backlog __read_mostly = 1000;
  int netdev_budget __read_mostly = 300;
  int weight_p __read_mostly = 64;            /* old backlog weight */

  
  DEFINE_PER_CPU(struct netif_rx_stats, netdev_rx_stat) = { 0, };

  /**
   *	netif_rx	-	post buffer to the network code
   *	@skb: buffer to post
   *
   *	This function receives a packet from a device driver and queues it for
   *	the upper (protocol) levels to process.  It always succeeds. The buffer
   *	may be dropped during processing for congestion control or by the
   *	protocol layers.
   *
   *	return values:
   *	NET_RX_SUCCESS	(no congestion)

   *	NET_RX_DROP     (packet was dropped)
   *
   */
  
  int netif_rx(struct sk_buff *skb)
  {

  	struct softnet_data *queue;
  	unsigned long flags;
  
  	/* if netpoll wants it, pretend we never saw it */
  	if (netpoll_rx(skb))
  		return NET_RX_DROP;

  	if (!skb->tstamp.tv64)

  		net_timestamp(skb);

  
  	/*
  	 * The code is rearranged so that the path is the most
  	 * short when CPU is congested, but is still operating.
  	 */
  	local_irq_save(flags);

  	queue = &__get_cpu_var(softnet_data);
  
  	__get_cpu_var(netdev_rx_stat).total++;
  	if (queue->input_pkt_queue.qlen <= netdev_max_backlog) {
  		if (queue->input_pkt_queue.qlen) {

  enqueue:
  			dev_hold(skb->dev);
  			__skb_queue_tail(&queue->input_pkt_queue, skb);

  			local_irq_restore(flags);

  			return NET_RX_SUCCESS;

  		}

  		napi_schedule(&queue->backlog);

  		goto enqueue;
  	}

  	__get_cpu_var(netdev_rx_stat).dropped++;
  	local_irq_restore(flags);
  
  	kfree_skb(skb);
  	return NET_RX_DROP;
  }
  
  int netif_rx_ni(struct sk_buff *skb)
  {
  	int err;
  
  	preempt_disable();
  	err = netif_rx(skb);
  	if (local_softirq_pending())
  		do_softirq();
  	preempt_enable();
  
  	return err;
  }
  
  EXPORT_SYMBOL(netif_rx_ni);

  static inline struct net_device *skb_bond(struct sk_buff *skb)

  {
  	struct net_device *dev = skb->dev;

  	if (dev->master) {

  		if (skb_bond_should_drop(skb)) {

  			kfree_skb(skb);
  			return NULL;
  		}

  		skb->dev = dev->master;

  	}

  
  	return dev;

  }

  static void net_tx_action(struct softirq_action *h)
  {
  	struct softnet_data *sd = &__get_cpu_var(softnet_data);
  
  	if (sd->completion_queue) {
  		struct sk_buff *clist;
  
  		local_irq_disable();
  		clist = sd->completion_queue;
  		sd->completion_queue = NULL;
  		local_irq_enable();
  
  		while (clist) {
  			struct sk_buff *skb = clist;
  			clist = clist->next;
  
  			BUG_TRAP(!atomic_read(&skb->users));
  			__kfree_skb(skb);
  		}
  	}
  
  	if (sd->output_queue) {
  		struct net_device *head;
  
  		local_irq_disable();
  		head = sd->output_queue;
  		sd->output_queue = NULL;
  		local_irq_enable();
  
  		while (head) {
  			struct net_device *dev = head;
  			head = head->next_sched;
  
  			smp_mb__before_clear_bit();
  			clear_bit(__LINK_STATE_SCHED, &dev->state);
  
  			if (spin_trylock(&dev->queue_lock)) {
  				qdisc_run(dev);
  				spin_unlock(&dev->queue_lock);
  			} else {
  				netif_schedule(dev);
  			}
  		}
  	}
  }

  static inline int deliver_skb(struct sk_buff *skb,
  			      struct packet_type *pt_prev,
  			      struct net_device *orig_dev)

  {
  	atomic_inc(&skb->users);

  	return pt_prev->func(skb, skb->dev, pt_prev, orig_dev);

  }
  
  #if defined(CONFIG_BRIDGE) || defined (CONFIG_BRIDGE_MODULE)

  /* These hooks defined here for ATM */

  struct net_bridge;
  struct net_bridge_fdb_entry *(*br_fdb_get_hook)(struct net_bridge *br,
  						unsigned char *addr);

  void (*br_fdb_put_hook)(struct net_bridge_fdb_entry *ent) __read_mostly;

  /*
   * If bridge module is loaded call bridging hook.
   *  returns NULL if packet was consumed.
   */
  struct sk_buff *(*br_handle_frame_hook)(struct net_bridge_port *p,
  					struct sk_buff *skb) __read_mostly;
  static inline struct sk_buff *handle_bridge(struct sk_buff *skb,
  					    struct packet_type **pt_prev, int *ret,
  					    struct net_device *orig_dev)

  {
  	struct net_bridge_port *port;

  	if (skb->pkt_type == PACKET_LOOPBACK ||
  	    (port = rcu_dereference(skb->dev->br_port)) == NULL)
  		return skb;

  
  	if (*pt_prev) {

  		*ret = deliver_skb(skb, *pt_prev, orig_dev);

  		*pt_prev = NULL;

  	}

  	return br_handle_frame_hook(port, skb);

  }
  #else

  #define handle_bridge(skb, pt_prev, ret, orig_dev)	(skb)

  #endif

  #if defined(CONFIG_MACVLAN) || defined(CONFIG_MACVLAN_MODULE)
  struct sk_buff *(*macvlan_handle_frame_hook)(struct sk_buff *skb) __read_mostly;
  EXPORT_SYMBOL_GPL(macvlan_handle_frame_hook);
  
  static inline struct sk_buff *handle_macvlan(struct sk_buff *skb,
  					     struct packet_type **pt_prev,
  					     int *ret,
  					     struct net_device *orig_dev)
  {
  	if (skb->dev->macvlan_port == NULL)
  		return skb;
  
  	if (*pt_prev) {
  		*ret = deliver_skb(skb, *pt_prev, orig_dev);
  		*pt_prev = NULL;
  	}
  	return macvlan_handle_frame_hook(skb);
  }
  #else
  #define handle_macvlan(skb, pt_prev, ret, orig_dev)	(skb)
  #endif

  #ifdef CONFIG_NET_CLS_ACT
  /* TODO: Maybe we should just force sch_ingress to be compiled in
   * when CONFIG_NET_CLS_ACT is? otherwise some useless instructions
   * a compare and 2 stores extra right now if we dont have it on
   * but have CONFIG_NET_CLS_ACT

   * NOTE: This doesnt stop any functionality; if you dont have

   * the ingress scheduler, you just cant add policies on ingress.
   *
   */

  static int ing_filter(struct sk_buff *skb)

  {
  	struct Qdisc *q;
  	struct net_device *dev = skb->dev;
  	int result = TC_ACT_OK;

  	u32 ttl = G_TC_RTTL(skb->tc_verd);

  	if (MAX_RED_LOOP < ttl++) {
  		printk(KERN_WARNING
  		       "Redir loop detected Dropping packet (%d->%d)
  ",
  		       skb->iif, dev->ifindex);
  		return TC_ACT_SHOT;
  	}

  	skb->tc_verd = SET_TC_RTTL(skb->tc_verd, ttl);
  	skb->tc_verd = SET_TC_AT(skb->tc_verd, AT_INGRESS);

  	spin_lock(&dev->ingress_lock);
  	if ((q = dev->qdisc_ingress) != NULL)
  		result = q->enqueue(skb, q);
  	spin_unlock(&dev->ingress_lock);
  
  	return result;
  }

  static inline struct sk_buff *handle_ing(struct sk_buff *skb,
  					 struct packet_type **pt_prev,
  					 int *ret, struct net_device *orig_dev)
  {
  	if (!skb->dev->qdisc_ingress)
  		goto out;

  	if (*pt_prev) {
  		*ret = deliver_skb(skb, *pt_prev, orig_dev);
  		*pt_prev = NULL;
  	} else {
  		/* Huh? Why does turning on AF_PACKET affect this? */
  		skb->tc_verd = SET_TC_OK2MUNGE(skb->tc_verd);

  	}

  	switch (ing_filter(skb)) {
  	case TC_ACT_SHOT:
  	case TC_ACT_STOLEN:
  		kfree_skb(skb);
  		return NULL;
  	}
  
  out:
  	skb->tc_verd = 0;
  	return skb;

  }
  #endif

  /**
   *	netif_receive_skb - process receive buffer from network
   *	@skb: buffer to process
   *
   *	netif_receive_skb() is the main receive data processing function.
   *	It always succeeds. The buffer may be dropped during processing
   *	for congestion control or by the protocol layers.
   *
   *	This function may only be called from softirq context and interrupts
   *	should be enabled.
   *
   *	Return values (usually ignored):
   *	NET_RX_SUCCESS: no congestion
   *	NET_RX_DROP: packet was dropped
   */

  int netif_receive_skb(struct sk_buff *skb)
  {
  	struct packet_type *ptype, *pt_prev;

  	struct net_device *orig_dev;

  	int ret = NET_RX_DROP;

  	__be16 type;

  
  	/* if we've gotten here through NAPI, check netpoll */

  	if (netpoll_receive_skb(skb))

  		return NET_RX_DROP;

  	if (!skb->tstamp.tv64)

  		net_timestamp(skb);

  	if (!skb->iif)
  		skb->iif = skb->dev->ifindex;

  	orig_dev = skb_bond(skb);

  	if (!orig_dev)
  		return NET_RX_DROP;

  	__get_cpu_var(netdev_rx_stat).total++;

  	skb_reset_network_header(skb);

  	skb_reset_transport_header(skb);

  	skb->mac_len = skb->network_header - skb->mac_header;

  
  	pt_prev = NULL;
  
  	rcu_read_lock();

  	/* Don't receive packets in an exiting network namespace */
  	if (!net_alive(dev_net(skb->dev)))
  		goto out;

  #ifdef CONFIG_NET_CLS_ACT
  	if (skb->tc_verd & TC_NCLS) {
  		skb->tc_verd = CLR_TC_NCLS(skb->tc_verd);
  		goto ncls;
  	}
  #endif
  
  	list_for_each_entry_rcu(ptype, &ptype_all, list) {
  		if (!ptype->dev || ptype->dev == skb->dev) {

  			if (pt_prev)

  				ret = deliver_skb(skb, pt_prev, orig_dev);

  			pt_prev = ptype;
  		}
  	}
  
  #ifdef CONFIG_NET_CLS_ACT

  	skb = handle_ing(skb, &pt_prev, &ret, orig_dev);
  	if (!skb)

  		goto out;

  ncls:
  #endif

  	skb = handle_bridge(skb, &pt_prev, &ret, orig_dev);
  	if (!skb)

  		goto out;

  	skb = handle_macvlan(skb, &pt_prev, &ret, orig_dev);
  	if (!skb)
  		goto out;

  
  	type = skb->protocol;

  	list_for_each_entry_rcu(ptype,
  			&ptype_base[ntohs(type) & PTYPE_HASH_MASK], list) {

  		if (ptype->type == type &&
  		    (!ptype->dev || ptype->dev == skb->dev)) {

  			if (pt_prev)

  				ret = deliver_skb(skb, pt_prev, orig_dev);

  			pt_prev = ptype;
  		}
  	}
  
  	if (pt_prev) {

  		ret = pt_prev->func(skb, skb->dev, pt_prev, orig_dev);

  	} else {
  		kfree_skb(skb);
  		/* Jamal, now you will not able to escape explaining
  		 * me how you were going to use this. :-)
  		 */
  		ret = NET_RX_DROP;
  	}
  
  out:
  	rcu_read_unlock();
  	return ret;
  }

  static int process_backlog(struct napi_struct *napi, int quota)

  {
  	int work = 0;

  	struct softnet_data *queue = &__get_cpu_var(softnet_data);
  	unsigned long start_time = jiffies;

  	napi->weight = weight_p;
  	do {

  		struct sk_buff *skb;
  		struct net_device *dev;
  
  		local_irq_disable();
  		skb = __skb_dequeue(&queue->input_pkt_queue);

  		if (!skb) {
  			__napi_complete(napi);
  			local_irq_enable();
  			break;
  		}

  		local_irq_enable();
  
  		dev = skb->dev;
  
  		netif_receive_skb(skb);
  
  		dev_put(dev);

  	} while (++work < quota && jiffies == start_time);

  	return work;
  }

  /**
   * __napi_schedule - schedule for receive

   * @n: entry to schedule

   *
   * The entry's receive function will be scheduled to run
   */

  void __napi_schedule(struct napi_struct *n)

  {
  	unsigned long flags;

  	local_irq_save(flags);
  	list_add_tail(&n->poll_list, &__get_cpu_var(softnet_data).poll_list);
  	__raise_softirq_irqoff(NET_RX_SOFTIRQ);
  	local_irq_restore(flags);

  }

  EXPORT_SYMBOL(__napi_schedule);

  
  static void net_rx_action(struct softirq_action *h)
  {

  	struct list_head *list = &__get_cpu_var(softnet_data).poll_list;

  	unsigned long start_time = jiffies;

  	int budget = netdev_budget;

  	void *have;

  	local_irq_disable();

  	while (!list_empty(list)) {
  		struct napi_struct *n;
  		int work, weight;

  		/* If softirq window is exhuasted then punt.
  		 *
  		 * Note that this is a slight policy change from the
  		 * previous NAPI code, which would allow up to 2
  		 * jiffies to pass before breaking out.  The test
  		 * used to be "jiffies - start_time > 1".
  		 */
  		if (unlikely(budget <= 0 || jiffies != start_time))

  			goto softnet_break;
  
  		local_irq_enable();

  		/* Even though interrupts have been re-enabled, this
  		 * access is safe because interrupts can only add new
  		 * entries to the tail of this list, and only ->poll()
  		 * calls can remove this head entry from the list.
  		 */
  		n = list_entry(list->next, struct napi_struct, poll_list);

  		have = netpoll_poll_lock(n);
  
  		weight = n->weight;

  		/* This NAPI_STATE_SCHED test is for avoiding a race
  		 * with netpoll's poll_napi().  Only the entity which
  		 * obtains the lock and sees NAPI_STATE_SCHED set will
  		 * actually make the ->poll() call.  Therefore we avoid
  		 * accidently calling ->poll() when NAPI is not scheduled.
  		 */
  		work = 0;
  		if (test_bit(NAPI_STATE_SCHED, &n->state))
  			work = n->poll(n, weight);

  
  		WARN_ON_ONCE(work > weight);
  
  		budget -= work;
  
  		local_irq_disable();
  
  		/* Drivers must not modify the NAPI state if they
  		 * consume the entire weight.  In such cases this code
  		 * still "owns" the NAPI instance and therefore can
  		 * move the instance around on the list at-will.
  		 */

  		if (unlikely(work == weight)) {
  			if (unlikely(napi_disable_pending(n)))
  				__napi_complete(n);
  			else
  				list_move_tail(&n->poll_list, list);
  		}

  
  		netpoll_poll_unlock(have);

  	}
  out:

  	local_irq_enable();

  #ifdef CONFIG_NET_DMA
  	/*
  	 * There may not be any more sk_buffs coming right now, so push
  	 * any pending DMA copies to hardware
  	 */

  	if (!cpus_empty(net_dma.channel_mask)) {
  		int chan_idx;
  		for_each_cpu_mask(chan_idx, net_dma.channel_mask) {
  			struct dma_chan *chan = net_dma.channels[chan_idx];
  			if (chan)
  				dma_async_memcpy_issue_pending(chan);
  		}

  	}
  #endif

  	return;
  
  softnet_break:
  	__get_cpu_var(netdev_rx_stat).time_squeeze++;
  	__raise_softirq_irqoff(NET_RX_SOFTIRQ);
  	goto out;
  }
  
  static gifconf_func_t * gifconf_list [NPROTO];
  
  /**
   *	register_gifconf	-	register a SIOCGIF handler
   *	@family: Address family
   *	@gifconf: Function handler
   *
   *	Register protocol dependent address dumping routines. The handler
   *	that is passed must not be freed or reused until it has been replaced
   *	by another handler.
   */
  int register_gifconf(unsigned int family, gifconf_func_t * gifconf)
  {
  	if (family >= NPROTO)
  		return -EINVAL;
  	gifconf_list[family] = gifconf;
  	return 0;
  }
  
  
  /*
   *	Map an interface index to its name (SIOCGIFNAME)
   */
  
  /*
   *	We need this ioctl for efficient implementation of the
   *	if_indextoname() function required by the IPv6 API.  Without
   *	it, we would have to search all the interfaces to find a
   *	match.  --pb
   */

  static int dev_ifname(struct net *net, struct ifreq __user *arg)

  {
  	struct net_device *dev;
  	struct ifreq ifr;
  
  	/*
  	 *	Fetch the caller's info block.
  	 */
  
  	if (copy_from_user(&ifr, arg, sizeof(struct ifreq)))
  		return -EFAULT;
  
  	read_lock(&dev_base_lock);

  	dev = __dev_get_by_index(net, ifr.ifr_ifindex);

  	if (!dev) {
  		read_unlock(&dev_base_lock);
  		return -ENODEV;
  	}
  
  	strcpy(ifr.ifr_name, dev->name);
  	read_unlock(&dev_base_lock);
  
  	if (copy_to_user(arg, &ifr, sizeof(struct ifreq)))
  		return -EFAULT;
  	return 0;
  }
  
  /*
   *	Perform a SIOCGIFCONF call. This structure will change
   *	size eventually, and there is nothing I can do about it.
   *	Thus we will need a 'compatibility mode'.
   */

  static int dev_ifconf(struct net *net, char __user *arg)

  {
  	struct ifconf ifc;
  	struct net_device *dev;
  	char __user *pos;
  	int len;
  	int total;
  	int i;
  
  	/*
  	 *	Fetch the caller's info block.
  	 */
  
  	if (copy_from_user(&ifc, arg, sizeof(struct ifconf)))
  		return -EFAULT;
  
  	pos = ifc.ifc_buf;
  	len = ifc.ifc_len;
  
  	/*
  	 *	Loop over the interfaces, and write an info block for each.
  	 */
  
  	total = 0;

  	for_each_netdev(net, dev) {

  		for (i = 0; i < NPROTO; i++) {
  			if (gifconf_list[i]) {
  				int done;
  				if (!pos)
  					done = gifconf_list[i](dev, NULL, 0);
  				else
  					done = gifconf_list[i](dev, pos + total,
  							       len - total);
  				if (done < 0)
  					return -EFAULT;
  				total += done;
  			}
  		}

  	}

  
  	/*
  	 *	All done.  Write the updated control block back to the caller.
  	 */
  	ifc.ifc_len = total;
  
  	/*
  	 * 	Both BSD and Solaris return 0 here, so we do too.
  	 */
  	return copy_to_user(arg, &ifc, sizeof(struct ifconf)) ? -EFAULT : 0;
  }
  
  #ifdef CONFIG_PROC_FS
  /*
   *	This is invoked by the /proc filesystem handler to display a device
   *	in detail.
   */

  void *dev_seq_start(struct seq_file *seq, loff_t *pos)

  	__acquires(dev_base_lock)

  {

  	struct net *net = seq_file_net(seq);

  	loff_t off;

  	struct net_device *dev;

  	read_lock(&dev_base_lock);
  	if (!*pos)
  		return SEQ_START_TOKEN;

  	off = 1;

  	for_each_netdev(net, dev)

  		if (off++ == *pos)
  			return dev;

  	return NULL;

  }
  
  void *dev_seq_next(struct seq_file *seq, void *v, loff_t *pos)
  {

  	struct net *net = seq_file_net(seq);

  	++*pos;

  	return v == SEQ_START_TOKEN ?

  		first_net_device(net) : next_net_device((struct net_device *)v);

  }
  
  void dev_seq_stop(struct seq_file *seq, void *v)

  	__releases(dev_base_lock)

  {
  	read_unlock(&dev_base_lock);
  }
  
  static void dev_seq_printf_stats(struct seq_file *seq, struct net_device *dev)
  {

  	struct net_device_stats *stats = dev->get_stats(dev);

  	seq_printf(seq, "%6s:%8lu %7lu %4lu %4lu %4lu %5lu %10lu %9lu "
  		   "%8lu %7lu %4lu %4lu %4lu %5lu %7lu %10lu
  ",
  		   dev->name, stats->rx_bytes, stats->rx_packets,
  		   stats->rx_errors,
  		   stats->rx_dropped + stats->rx_missed_errors,
  		   stats->rx_fifo_errors,
  		   stats->rx_length_errors + stats->rx_over_errors +
  		    stats->rx_crc_errors + stats->rx_frame_errors,
  		   stats->rx_compressed, stats->multicast,
  		   stats->tx_bytes, stats->tx_packets,
  		   stats->tx_errors, stats->tx_dropped,
  		   stats->tx_fifo_errors, stats->collisions,
  		   stats->tx_carrier_errors +
  		    stats->tx_aborted_errors +
  		    stats->tx_window_errors +
  		    stats->tx_heartbeat_errors,
  		   stats->tx_compressed);

  }
  
  /*
   *	Called from the PROCfs module. This now uses the new arbitrary sized
   *	/proc/net interface to create /proc/net/dev
   */
  static int dev_seq_show(struct seq_file *seq, void *v)
  {
  	if (v == SEQ_START_TOKEN)
  		seq_puts(seq, "Inter-|   Receive                            "
  			      "                    |  Transmit
  "
  			      " face |bytes    packets errs drop fifo frame "
  			      "compressed multicast|bytes    packets errs "
  			      "drop fifo colls carrier compressed
  ");
  	else
  		dev_seq_printf_stats(seq, v);
  	return 0;
  }
  
  static struct netif_rx_stats *softnet_get_online(loff_t *pos)
  {
  	struct netif_rx_stats *rc = NULL;

  	while (*pos < nr_cpu_ids)

  		if (cpu_online(*pos)) {

  			rc = &per_cpu(netdev_rx_stat, *pos);
  			break;
  		} else
  			++*pos;
  	return rc;
  }
  
  static void *softnet_seq_start(struct seq_file *seq, loff_t *pos)
  {
  	return softnet_get_online(pos);
  }
  
  static void *softnet_seq_next(struct seq_file *seq, void *v, loff_t *pos)
  {
  	++*pos;
  	return softnet_get_online(pos);
  }
  
  static void softnet_seq_stop(struct seq_file *seq, void *v)
  {
  }
  
  static int softnet_seq_show(struct seq_file *seq, void *v)
  {
  	struct netif_rx_stats *s = v;
  
  	seq_printf(seq, "%08x %08x %08x %08x %08x %08x %08x %08x %08x
  ",

  		   s->total, s->dropped, s->time_squeeze, 0,

  		   0, 0, 0, 0, /* was fastroute */
  		   s->cpu_collision );

  	return 0;
  }

  static const struct seq_operations dev_seq_ops = {

  	.start = dev_seq_start,
  	.next  = dev_seq_next,
  	.stop  = dev_seq_stop,
  	.show  = dev_seq_show,
  };
  
  static int dev_seq_open(struct inode *inode, struct file *file)
  {

  	return seq_open_net(inode, file, &dev_seq_ops,
  			    sizeof(struct seq_net_private));

  }

  static const struct file_operations dev_seq_fops = {

  	.owner	 = THIS_MODULE,
  	.open    = dev_seq_open,
  	.read    = seq_read,
  	.llseek  = seq_lseek,

  	.release = seq_release_net,

  };

  static const struct seq_operations softnet_seq_ops = {

  	.start = softnet_seq_start,
  	.next  = softnet_seq_next,
  	.stop  = softnet_seq_stop,
  	.show  = softnet_seq_show,
  };
  
  static int softnet_seq_open(struct inode *inode, struct file *file)
  {
  	return seq_open(file, &softnet_seq_ops);
  }

  static const struct file_operations softnet_seq_fops = {

  	.owner	 = THIS_MODULE,
  	.open    = softnet_seq_open,
  	.read    = seq_read,
  	.llseek  = seq_lseek,
  	.release = seq_release,
  };

  static void *ptype_get_idx(loff_t pos)
  {
  	struct packet_type *pt = NULL;
  	loff_t i = 0;
  	int t;
  
  	list_for_each_entry_rcu(pt, &ptype_all, list) {
  		if (i == pos)
  			return pt;
  		++i;
  	}

  	for (t = 0; t < PTYPE_HASH_SIZE; t++) {

  		list_for_each_entry_rcu(pt, &ptype_base[t], list) {
  			if (i == pos)
  				return pt;
  			++i;
  		}
  	}
  	return NULL;
  }
  
  static void *ptype_seq_start(struct seq_file *seq, loff_t *pos)

  	__acquires(RCU)

  {
  	rcu_read_lock();
  	return *pos ? ptype_get_idx(*pos - 1) : SEQ_START_TOKEN;
  }
  
  static void *ptype_seq_next(struct seq_file *seq, void *v, loff_t *pos)
  {
  	struct packet_type *pt;
  	struct list_head *nxt;
  	int hash;
  
  	++*pos;
  	if (v == SEQ_START_TOKEN)
  		return ptype_get_idx(0);
  
  	pt = v;
  	nxt = pt->list.next;
  	if (pt->type == htons(ETH_P_ALL)) {
  		if (nxt != &ptype_all)
  			goto found;
  		hash = 0;
  		nxt = ptype_base[0].next;
  	} else

  		hash = ntohs(pt->type) & PTYPE_HASH_MASK;

  
  	while (nxt == &ptype_base[hash]) {

  		if (++hash >= PTYPE_HASH_SIZE)

  			return NULL;
  		nxt = ptype_base[hash].next;
  	}
  found:
  	return list_entry(nxt, struct packet_type, list);
  }
  
  static void ptype_seq_stop(struct seq_file *seq, void *v)

  	__releases(RCU)

  {
  	rcu_read_unlock();
  }
  
  static void ptype_seq_decode(struct seq_file *seq, void *sym)
  {
  #ifdef CONFIG_KALLSYMS
  	unsigned long offset = 0, symsize;
  	const char *symname;
  	char *modname;
  	char namebuf[128];
  
  	symname = kallsyms_lookup((unsigned long)sym, &symsize, &offset,
  				  &modname, namebuf);
  
  	if (symname) {
  		char *delim = ":";
  
  		if (!modname)
  			modname = delim = "";
  		seq_printf(seq, "%s%s%s%s+0x%lx", delim, modname, delim,
  			   symname, offset);
  		return;
  	}
  #endif
  
  	seq_printf(seq, "[%p]", sym);
  }
  
  static int ptype_seq_show(struct seq_file *seq, void *v)
  {
  	struct packet_type *pt = v;
  
  	if (v == SEQ_START_TOKEN)
  		seq_puts(seq, "Type Device      Function
  ");

  	else if (pt->dev == NULL || dev_net(pt->dev) == seq_file_net(seq)) {

  		if (pt->type == htons(ETH_P_ALL))
  			seq_puts(seq, "ALL ");
  		else
  			seq_printf(seq, "%04x", ntohs(pt->type));
  
  		seq_printf(seq, " %-8s ",
  			   pt->dev ? pt->dev->name : "");
  		ptype_seq_decode(seq,  pt->func);
  		seq_putc(seq, '
  ');
  	}
  
  	return 0;
  }
  
  static const struct seq_operations ptype_seq_ops = {
  	.start = ptype_seq_start,
  	.next  = ptype_seq_next,
  	.stop  = ptype_seq_stop,
  	.show  = ptype_seq_show,
  };
  
  static int ptype_seq_open(struct inode *inode, struct file *file)
  {

  	return seq_open_net(inode, file, &ptype_seq_ops,
  			sizeof(struct seq_net_private));

  }
  
  static const struct file_operations ptype_seq_fops = {
  	.owner	 = THIS_MODULE,
  	.open    = ptype_seq_open,
  	.read    = seq_read,
  	.llseek  = seq_lseek,

  	.release = seq_release_net,

  };

  static int __net_init dev_proc_net_init(struct net *net)

  {
  	int rc = -ENOMEM;

  	if (!proc_net_fops_create(net, "dev", S_IRUGO, &dev_seq_fops))

  		goto out;

  	if (!proc_net_fops_create(net, "softnet_stat", S_IRUGO, &softnet_seq_fops))