/*
 *      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/hash.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/ethtool.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 <net/xfrm.h>
#include <linux/highmem.h>
#include <linux/init.h>
#include <linux/kmod.h>
#include <linux/module.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 <linux/ip.h>
#include <net/ip.h>
#include <linux/ipv6.h>
#include <linux/in.h>
#include <linux/jhash.h>
#include <linux/random.h>
#include <trace/events/napi.h>

#include "net-sysfs.h"

/* Instead of increasing this, you should create a hash table. */
#define MAX_GRO_SKBS 8

/* This should be increased if a protocol with a bigger head is added. */
#define GRO_MAX_HEAD (MAX_HEADER + 128)

/*
 *      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 */

/*
 * The @dev_base_head list is protected by @dev_base_lock and the rtnl
 * semaphore.
 *
 * Pure readers hold dev_base_lock for reading, or rcu_read_lock()
 *
 * 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);

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_32(hash, NETDEV_HASHBITS)];
}

static inline struct hlist_head *dev_index_hash(struct net *net, int ifindex)
{
        return &net->dev_index_head[ifindex & (NETDEV_HASHENTRIES - 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_rcu(&dev->dev_list, &net->dev_base_head);
        hlist_add_head_rcu(&dev->name_hlist, dev_name_hash(net, dev->name));
        hlist_add_head_rcu(&dev->index_hlist,
                           dev_index_hash(net, dev->ifindex));
        write_unlock_bh(&dev_base_lock);
        return 0;
}

/* Device list removal
 * caller must respect a RCU grace period before freeing/reusing dev
 */
static void unlist_netdevice(struct net_device *dev)
{
        ASSERT_RTNL();

        /* Unlink dev from the device chain */
        write_lock_bh(&dev_base_lock);
        list_del_rcu(&dev->dev_list);
        hlist_del_rcu(&dev->name_hlist);
        hlist_del_rcu(&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);
EXPORT_PER_CPU_SYMBOL(softnet_data);

#ifdef CONFIG_LOCKDEP
/*
 * register_netdevice() inits txq->_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_PHONET,
         ARPHRD_PHONET_PIPE, ARPHRD_IEEE802154,
         ARPHRD_VOID, ARPHRD_NONE};

static const char *const 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_PHONET",
         "_xmit_PHONET_PIPE", "_xmit_IEEE802154",
         "_xmit_VOID", "_xmit_NONE"};

static struct lock_class_key netdev_xmit_lock_key[ARRAY_SIZE(netdev_lock_type)];
static struct lock_class_key netdev_addr_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_xmit_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]);
}

static inline void netdev_set_addr_lockdep_class(struct net_device *dev)
{
        int i;

        i = netdev_lock_pos(dev->type);
        lockdep_set_class_and_name(&dev->addr_list_lock,
                                   &netdev_addr_lock_key[i],
                                   netdev_lock_name[i]);
}
#else
static inline void netdev_set_xmit_lockdep_class(spinlock_t *lock,
                                                 unsigned short dev_type)
{
}
static inline void netdev_set_addr_lockdep_class(struct net_device *dev)
{
}
#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);
}
EXPORT_SYMBOL(dev_add_pack);

/**
 *      __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.\n", pt);
out:
        spin_unlock_bh(&ptype_lock);
}
EXPORT_SYMBOL(__dev_remove_pack);

/**
 *      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();
}
EXPORT_SYMBOL(dev_remove_pack);

/******************************************************************************

                      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));
                        strlcpy(s[i].name, name, IFNAMSIZ);
                        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] != ' ' &&
                    !strcmp(dev->name, 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;
}
EXPORT_SYMBOL(netdev_boot_setup_check);


/**
 *      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;
        struct net_device *dev;
        struct hlist_head *head = dev_name_hash(net, name);

        hlist_for_each_entry(dev, p, head, name_hlist)
                if (!strncmp(dev->name, name, IFNAMSIZ))
                        return dev;

        return NULL;
}
EXPORT_SYMBOL(__dev_get_by_name);

/**
 *      dev_get_by_name_rcu     - find a device by its name
 *      @net: the applicable net namespace
 *      @name: name to find
 *
 *      Find an interface by name.
 *      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. The caller must hold RCU lock.
 */

struct net_device *dev_get_by_name_rcu(struct net *net, const char *name)
{
        struct hlist_node *p;
        struct net_device *dev;
        struct hlist_head *head = dev_name_hash(net, name);

        hlist_for_each_entry_rcu(dev, p, head, name_hlist)
                if (!strncmp(dev->name, name, IFNAMSIZ))
                        return dev;

        return NULL;
}
EXPORT_SYMBOL(dev_get_by_name_rcu);

/**
 *      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;

        rcu_read_lock();
        dev = dev_get_by_name_rcu(net, name);
        if (dev)
                dev_hold(dev);
        rcu_read_unlock();
        return dev;
}
EXPORT_SYMBOL(dev_get_by_name);

/**
 *      __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;
        struct net_device *dev;
        struct hlist_head *head = dev_index_hash(net, ifindex);

        hlist_for_each_entry(dev, p, head, index_hlist)
                if (dev->ifindex == ifindex)
                        return dev;

        return NULL;
}
EXPORT_SYMBOL(__dev_get_by_index);

/**
 *      dev_get_by_index_rcu - 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 RCU lock.
 */

struct net_device *dev_get_by_index_rcu(struct net *net, int ifindex)
{
        struct hlist_node *p;
        struct net_device *dev;
        struct hlist_head *head = dev_index_hash(net, ifindex);

        hlist_for_each_entry_rcu(dev, p, head, index_hlist)
                if (dev->ifindex == ifindex)
                        return dev;

        return NULL;
}
EXPORT_SYMBOL(dev_get_by_index_rcu);


/**
 *      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;

        rcu_read_lock();
        dev = dev_get_by_index_rcu(net, ifindex);
        if (dev)
                dev_hold(dev);
        rcu_read_unlock();
        return dev;
}
EXPORT_SYMBOL(dev_get_by_index);

/**
 *      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;
        rcu_read_lock();
        for_each_netdev_rcu(net, dev) {
                if (((dev->flags ^ if_flags) & mask) == 0) {
                        dev_hold(dev);
                        ret = dev;
                        break;
                }
        }
        rcu_read_unlock();
        return ret;
}
EXPORT_SYMBOL(dev_get_by_flags);

/**
 *      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;
}
EXPORT_SYMBOL(dev_valid_name);

/**
 *      __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);
        }

        if (buf != name)
                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;
}
EXPORT_SYMBOL(dev_alloc_name);

static int dev_get_valid_name(struct net *net, const char *name, char *buf,
                              bool fmt)
{
        if (!dev_valid_name(name))
                return -EINVAL;

        if (fmt && strchr(name, '%'))
                return __dev_alloc_name(net, name, buf);
        else if (__dev_get_by_name(net, name))
                return -EEXIST;
        else if (buf != name)
                strlcpy(buf, name, IFNAMSIZ);

        return 0;
}

/**
 *      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, const 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 (strncmp(newname, dev->name, IFNAMSIZ) == 0)
                return 0;

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

        err = dev_get_valid_name(net, newname, dev->name, 1);
        if (err < 0)
                return err;

rollback:
        /* For now only devices in the initial network namespace
         * are in sysfs.
         */
        if (net_eq(net, &init_net)) {
                ret = device_rename(&dev->dev, dev->name);
                if (ret) {
                        memcpy(dev->name, oldname, IFNAMSIZ);
                        return ret;
                }
        }

        write_lock_bh(&dev_base_lock);
        hlist_del(&dev->name_hlist);
        write_unlock_bh(&dev_base_lock);

        synchronize_rcu();

        write_lock_bh(&dev_base_lock);
        hlist_add_head_rcu(&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) {
                /* err >= 0 after dev_alloc_name() or stores the first errno */
                if (err >= 0) {
                        err = ret;
                        memcpy(dev->name, oldname, IFNAMSIZ);
                        goto rollback;
                } else {
                        printk(KERN_ERR
                               "%s: name change rollback failed: %d.\n",
                               dev->name, ret);
                }
        }

        return err;
}

/**
 *      dev_set_alias - change ifalias of a device
 *      @dev: device
 *      @alias: name up to IFALIASZ
 *      @len: limit of bytes to copy from info
 *
 *      Set ifalias for a device,
 */
int dev_set_alias(struct net_device *dev, const char *alias, size_t len)
{
        ASSERT_RTNL();

        if (len >= IFALIASZ)
                return -EINVAL;

        if (!len) {
                if (dev->ifalias) {
                        kfree(dev->ifalias);
                        dev->ifalias = NULL;
                }
                return 0;
        }

        dev->ifalias = krealloc(dev->ifalias, len + 1, GFP_KERNEL);
        if (!dev->ifalias)
                return -ENOMEM;

        strlcpy(dev->ifalias, alias, len+1);
        return len;
}


/**
 *      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);
        }
}
EXPORT_SYMBOL(netdev_state_change);

void netdev_bonding_change(struct net_device *dev, unsigned long event)
{
        call_netdevice_notifiers(event, dev);
}
EXPORT_SYMBOL(netdev_bonding_change);

/**
 *      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;

        rcu_read_lock();
        dev = dev_get_by_name_rcu(net, name);
        rcu_read_unlock();

        if (!dev && capable(CAP_NET_ADMIN))
                request_module("%s", name);
}
EXPORT_SYMBOL(dev_load);

/**
 *      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)
{
        const struct net_device_ops *ops = dev->netdev_ops;
        int ret;

        ASSERT_RTNL();

        /*
         *      Is it already up?
         */

        if (dev->flags & IFF_UP)
                return 0;

        /*
         *      Is it even present?
         */
        if (!netif_device_present(dev))
                return -ENODEV;

        ret = call_netdevice_notifiers(NETDEV_PRE_UP, dev);
        ret = notifier_to_errno(ret);
        if (ret)
                return ret;

        /*
         *      Call device private open method
         */
        set_bit(__LINK_STATE_START, &dev->state);

        if (ops->ndo_validate_addr)
                ret = ops->ndo_validate_addr(dev);

        if (!ret && ops->ndo_open)
                ret = ops->ndo_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;

                /*
                 *      Enable NET_DMA
                 */
                net_dmaengine_get();

                /*
                 *      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;
}
EXPORT_SYMBOL(dev_open);

/**
 *      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)
{
        const struct net_device_ops *ops = dev->netdev_ops;
        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 (ops->ndo_stop)
                ops->ndo_stop(dev);

        /*
         *      Device is now down.
         */

        dev->flags &= ~IFF_UP;

        /*
         * Tell people we are down
         */
        call_netdevice_notifiers(NETDEV_DOWN, dev);

        /*
         *      Shutdown NET_DMA
         */
        net_dmaengine_put();

        return 0;
}
EXPORT_SYMBOL(dev_close);


/**
 *      dev_disable_lro - disable Large Receive Offload on a device
 *      @dev: device
 *
 *      Disable Large Receive Offload (LRO) on a net device.  Must be
 *      called under RTNL.  This is needed if received packets may be
 *      forwarded to another interface.
 */
void dev_disable_lro(struct net_device *dev)
{
        if (dev->ethtool_ops && dev->ethtool_ops->get_flags &&
            dev->ethtool_ops->set_flags) {
                u32 flags = dev->ethtool_ops->get_flags(dev);
                if (flags & ETH_FLAG_LRO) {
                        flags &= ~ETH_FLAG_LRO;
                        dev->ethtool_ops->set_flags(dev, flags);
                }
        }
        WARN_ON(dev->features & NETIF_F_LRO);
}
EXPORT_SYMBOL(dev_disable_lro);


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

        raw_notifier_chain_unregister(&netdev_chain, nb);
        goto unlock;
}
EXPORT_SYMBOL(register_netdevice_notifier);

/**
 *      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;
}
EXPORT_SYMBOL(unregister_netdevice_notifier);

/**
 *      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);
}
EXPORT_SYMBOL(net_enable_timestamp);

void net_disable_timestamp(void)
{
        atomic_dec(&netstamp_needed);
}
EXPORT_SYMBOL(net_disable_timestamp);

static inline void net_timestamp(struct sk_buff *skb)
{
        if (atomic_read(&netstamp_needed))
                __net_timestamp(skb);
        else
                skb->tstamp.tv64 = 0;
}

/**
 * dev_forward_skb - loopback an skb to another netif
 *
 * @dev: destination network device
 * @skb: buffer to forward
 *
 * return values:
 *      NET_RX_SUCCESS  (no congestion)
 *      NET_RX_DROP     (packet was dropped)
 *
 * dev_forward_skb can be used for injecting an skb from the
 * start_xmit function of one device into the receive queue
 * of another device.
 *
 * The receiving device may be in another namespace, so
 * we have to clear all information in the skb that could
 * impact namespace isolation.
 */
int dev_forward_skb(struct net_device *dev, struct sk_buff *skb)
{
        skb_orphan(skb);

        if (!(dev->flags & IFF_UP))
                return NET_RX_DROP;

        if (skb->len > (dev->mtu + dev->hard_header_len))
                return NET_RX_DROP;

        skb_dst_drop(skb);
        skb->tstamp.tv64 = 0;
        skb->pkt_type = PACKET_HOST;
        skb->protocol = eth_type_trans(skb, dev);
        skb->mark = 0;
        secpath_reset(skb);
        nf_reset(skb);
        return netif_rx(skb);
}
EXPORT_SYMBOL_GPL(dev_forward_skb);

/*
 *      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;

#ifdef CONFIG_NET_CLS_ACT
        if (!(skb->tstamp.tv64 && (G_TC_FROM(skb->tc_verd) & AT_INGRESS)))
                net_timestamp(skb);
#else
        net_timestamp(skb);
#endif

        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\n",
                                               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();
}


static inline void __netif_reschedule(struct Qdisc *q)
{
        struct softnet_data *sd;
        unsigned long flags;

        local_irq_save(flags);
        sd = &__get_cpu_var(softnet_data);
        q->next_sched = sd->output_queue;
        sd->output_queue = q;
        raise_softirq_irqoff(NET_TX_SOFTIRQ);
        local_irq_restore(flags);
}

void __netif_schedule(struct Qdisc *q)
{
        if (!test_and_set_bit(__QDISC_STATE_SCHED, &q->state))
                __netif_reschedule(q);
}
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_tx_stop_all_queues(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_tx_wake_all_queues(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)) ||
                ((features & NETIF_F_FCOE_CRC) &&
                 protocol == htons(ETH_P_FCOE)));
}

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;
}
EXPORT_SYMBOL(skb_checksum_help);

/**
 *      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;

        skb_reset_mac_header(skb);
        skb->mac_len = skb->network_header - skb->mac_header;
        __skb_pull(skb, skb->mac_len);

        if (unlikely(skb->ip_summed != CHECKSUM_PARTIAL)) {
                struct net_device *dev = skb->dev;
                struct ethtool_drvinfo info = {};

                if (dev && dev->ethtool_ops && dev->ethtool_ops->get_drvinfo)
                        dev->ethtool_ops->get_drvinfo(dev, &info);

                WARN(1, "%s: caps=(0x%lx, 0x%lx) len=%d data_len=%d "
                        "ip_summed=%d",
                     info.driver, dev ? dev->features : 0L,
                     skb->sk ? skb->sk->sk_route_caps : 0L,
                     skb->len, skb->data_len, skb->ip_summed);

                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.\n",
                        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,
                        struct netdev_queue *txq)
{
        const struct net_device_ops *ops = dev->netdev_ops;
        int rc = NETDEV_TX_OK;

        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;
                }

                /*
                 * If device doesnt need skb->dst, release it right now while
                 * its hot in this cpu cache
                 */
                if (dev->priv_flags & IFF_XMIT_DST_RELEASE)
                        skb_dst_drop(skb);

                rc = ops->ndo_start_xmit(skb, dev);
                if (rc == NETDEV_TX_OK)
                        txq_trans_update(txq);
                /*
                 * TODO: if skb_orphan() was called by
                 * dev->hard_start_xmit() (for example, the unmodified
                 * igb driver does that; bnx2 doesn't), then
                 * skb_tx_software_timestamp() will be unable to send
                 * back the time stamp.
                 *
                 * How can this be prevented? Always create another
                 * reference to the socket before calling
                 * dev->hard_start_xmit()? Prevent that skb_orphan()
                 * does anything in dev->hard_start_xmit() by clearing
                 * the skb destructor before the call and restoring it
                 * afterwards, then doing the skb_orphan() ourselves?
                 */
                return rc;
        }

gso:
        do {
                struct sk_buff *nskb = skb->next;

                skb->next = nskb->next;
                nskb->next = NULL;
                rc = ops->ndo_start_xmit(nskb, dev);
                if (unlikely(rc != NETDEV_TX_OK)) {
                        if (rc & ~NETDEV_TX_MASK)
                                goto out_kfree_gso_skb;
                        nskb->next = skb->next;
                        skb->next = nskb;
                        return rc;
                }
                txq_trans_update(txq);
                if (unlikely(netif_tx_queue_stopped(txq) && skb->next))
                        return NETDEV_TX_BUSY;
        } while (skb->next);

out_kfree_gso_skb:
        if (likely(skb->next == NULL))
                skb->destructor = DEV_GSO_CB(skb)->destructor;
out_kfree_skb:
        kfree_skb(skb);
        return rc;
}

static u32 skb_tx_hashrnd;

u16 skb_tx_hash(const struct net_device *dev, const struct sk_buff *skb)
{
        u32 hash;

        if (skb_rx_queue_recorded(skb)) {
                hash = skb_get_rx_queue(skb);
                while (unlikely(hash >= dev->real_num_tx_queues))
                        hash -= dev->real_num_tx_queues;
                return hash;
        }

        if (skb->sk && skb->sk->sk_hash)
                hash = skb->sk->sk_hash;
        else
                hash = skb->protocol;

        hash = jhash_1word(hash, skb_tx_hashrnd);

        return (u16) (((u64) hash * dev->real_num_tx_queues) >> 32);
}
EXPORT_SYMBOL(skb_tx_hash);

static inline u16 dev_cap_txqueue(struct net_device *dev, u16 queue_index)
{
        if (unlikely(queue_index >= dev->real_num_tx_queues)) {
                if (net_ratelimit()) {
                        WARN(1, "%s selects TX queue %d, but "
                             "real number of TX queues is %d\n",
                             dev->name, queue_index,
                             dev->real_num_tx_queues);
                }
                return 0;
        }
        return queue_index;
}

static struct netdev_queue *dev_pick_tx(struct net_device *dev,
                                        struct sk_buff *skb)
{
        u16 queue_index;
        struct sock *sk = skb->sk;

        if (sk_tx_queue_recorded(sk)) {
                queue_index = sk_tx_queue_get(sk);
        } else {
                const struct net_device_ops *ops = dev->netdev_ops;

                if (ops->ndo_select_queue) {
                        queue_index = ops->ndo_select_queue(dev, skb);
                        queue_index = dev_cap_txqueue(dev, queue_index);
                } else {
                        queue_index = 0;
                        if (dev->real_num_tx_queues > 1)
                                queue_index = skb_tx_hash(dev, skb);

                        if (sk && sk->sk_dst_cache)
                                sk_tx_queue_set(sk, queue_index);
                }
        }

        skb_set_queue_mapping(skb, queue_index);
        return netdev_get_tx_queue(dev, queue_index);
}

static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q,
                                 struct net_device *dev,
                                 struct netdev_queue *txq)
{
        spinlock_t *root_lock = qdisc_lock(q);
        int rc;

        spin_lock(root_lock);
        if (unlikely(test_bit(__QDISC_STATE_DEACTIVATED, &q->state))) {
                kfree_skb(skb);
                rc = NET_XMIT_DROP;
        } else if ((q->flags & TCQ_F_CAN_BYPASS) && !qdisc_qlen(q) &&
                   !test_and_set_bit(__QDISC_STATE_RUNNING, &q->state)) {
                /*
                 * This is a work-conserving queue; there are no old skbs
                 * waiting to be sent out; and the qdisc is not running -
                 * xmit the skb directly.
                 */
                __qdisc_update_bstats(q, skb->len);
                if (sch_direct_xmit(skb, q, dev, txq, root_lock))
                        __qdisc_run(q);
                else
                        clear_bit(__QDISC_STATE_RUNNING, &q->state);

                rc = NET_XMIT_SUCCESS;
        } else {
                rc = qdisc_enqueue_root(skb, q);
                qdisc_run(q);
        }
        spin_unlock(root_lock);

        return rc;
}

/**
 *      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 netdev_queue *txq;
        struct Qdisc *q;
        int rc = -ENOMEM;

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

        if (skb_has_frags(skb) &&
            !(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:
        /* Disable soft irqs for various locks below. Also
         * stops preemption for RCU.
         */
        rcu_read_lock_bh();

        txq = dev_pick_tx(dev, skb);
        q = rcu_dereference(txq->qdisc);

#ifdef CONFIG_NET_CLS_ACT
        skb->tc_verd = SET_TC_AT(skb->tc_verd, AT_EGRESS);
#endif
        if (q->enqueue) {
                rc = __dev_xmit_skb(skb, q, dev, txq);
                goto out;
        }

        /* 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 (txq->xmit_lock_owner != cpu) {

                        HARD_TX_LOCK(dev, txq, cpu);

                        if (!netif_tx_queue_stopped(txq)) {
                                rc = dev_hard_start_xmit(skb, dev, txq);
                                if (dev_xmit_complete(rc)) {
                                        HARD_TX_UNLOCK(dev, txq);
                                        goto out;
                                }
                        }
                        HARD_TX_UNLOCK(dev, txq);
                        if (net_ratelimit())
                                printk(KERN_CRIT "Virtual device %s asks to "
                                       "queue packet!\n", 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!\n", dev->name);
                }
        }

        rc = -ENETDOWN;
        rcu_read_unlock_bh();

out_kfree_skb:
        kfree_skb(skb);
        return rc;
out:
        rcu_read_unlock_bh();
        return rc;
}
EXPORT_SYMBOL(dev_queue_xmit);


/*=======================================================================
                        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:
                        __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;
}
EXPORT_SYMBOL(netif_rx);

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 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;

                        WARN_ON(atomic_read(&skb->users));
                        __kfree_skb(skb);
                }
        }

        if (sd->output_queue) {
                struct Qdisc *head;

                local_irq_disable();
                head = sd->output_queue;
                sd->output_queue = NULL;
                local_irq_enable();

                while (head) {
                        struct Qdisc *q = head;
                        spinlock_t *root_lock;

                        head = head->next_sched;

                        root_lock = qdisc_lock(q);
                        if (spin_trylock(root_lock)) {
                                smp_mb__before_clear_bit();
                                clear_bit(__QDISC_STATE_SCHED,
                                          &q->state);
                                qdisc_run(q);
                                spin_unlock(root_lock);
                        } else {
                                if (!test_bit(__QDISC_STATE_DEACTIVATED,
                                              &q->state)) {
                                        __netif_reschedule(q);
                                } else {
                                        smp_mb__before_clear_bit();
                                        clear_bit(__QDISC_STATE_SCHED,
                                                  &q->state);
                                }
                        }
                }
        }
}

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)

#if defined(CONFIG_ATM_LANE) || defined(CONFIG_ATM_LANE_MODULE)
/* This hook is defined here for ATM LANE */
int (*br_fdb_test_addr_hook)(struct net_device *dev,
                             unsigned char *addr) __read_mostly;
EXPORT_SYMBOL_GPL(br_fdb_test_addr_hook);
#endif

/*
 * 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;
EXPORT_SYMBOL_GPL(br_handle_frame_hook);

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 net_device *dev = skb->dev;
        u32 ttl = G_TC_RTTL(skb->tc_verd);
        struct netdev_queue *rxq;
        int result = TC_ACT_OK;
        struct Qdisc *q;

        if (MAX_RED_LOOP < ttl++) {
                printk(KERN_WARNING
                       "Redir loop detected Dropping packet (%d->%d)\n",
                       skb->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);

        rxq = &dev->rx_queue;

        q = rxq->qdisc;
        if (q != &noop_qdisc) {
                spin_lock(qdisc_lock(q));
                if (likely(!test_bit(__QDISC_STATE_DEACTIVATED, &q->state)))
                        result = qdisc_enqueue_root(skb, q);
                spin_unlock(qdisc_lock(q));
        }

        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->rx_queue.qdisc == &noop_qdisc)
                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_nit_deliver - deliver received packets to network taps
 *      @skb: buffer
 *
 *      This function is used to deliver incoming packets to network
 *      taps. It should be used when the normal netif_receive_skb path
 *      is bypassed, for example because of VLAN acceleration.
 */
void netif_nit_deliver(struct sk_buff *skb)
{
        struct packet_type *ptype;

        if (list_empty(&ptype_all))
                return;

        skb_reset_network_header(skb);
        skb_reset_transport_header(skb);
        skb->mac_len = skb->network_header - skb->mac_header;

        rcu_read_lock();
        list_for_each_entry_rcu(ptype, &ptype_all, list) {
                if (!ptype->dev || ptype->dev == skb->dev)
                        deliver_skb(skb, ptype, skb->dev);
        }
        rcu_read_unlock();
}

/**
 *      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;
        struct net_device *null_or_orig;
        int ret = NET_RX_DROP;
        __be16 type;

        if (!skb->tstamp.tv64)
                net_timestamp(skb);

        if (vlan_tx_tag_present(skb) && vlan_hwaccel_do_receive(skb))
                return NET_RX_SUCCESS;

        /* if we've gotten here through NAPI, check netpoll */
        if (netpoll_receive_skb(skb))
                return NET_RX_DROP;

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

        null_or_orig = NULL;
        orig_dev = skb->dev;
        if (orig_dev->master) {
                if (skb_bond_should_drop(skb))
                        null_or_orig = orig_dev; /* deliver only exact match */
                else
                        skb->dev = orig_dev->master;
        }

        __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();

#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 == null_or_orig || ptype->dev == skb->dev ||
                    ptype->dev == orig_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 == null_or_orig || ptype->dev == skb->dev ||
                     ptype->dev == orig_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;
}
EXPORT_SYMBOL(netif_receive_skb);

/* Network device is going away, flush any packets still pending  */
static void flush_backlog(void *arg)
{
        struct net_device *dev = arg;
        struct softnet_data *queue = &__get_cpu_var(softnet_data);
        struct sk_buff *skb, *tmp;

        skb_queue_walk_safe(&queue->input_pkt_queue, skb, tmp)
                if (skb->dev == dev) {
                        __skb_unlink(skb, &queue->input_pkt_queue);
                        kfree_skb(skb);
                }
}

static int napi_gro_complete(struct sk_buff *skb)
{
        struct packet_type *ptype;
        __be16 type = skb->protocol;
        struct list_head *head = &ptype_base[ntohs(type) & PTYPE_HASH_MASK];
        int err = -ENOENT;

        if (NAPI_GRO_CB(skb)->count == 1) {
                skb_shinfo(skb)->gso_size = 0;
                goto out;
        }

        rcu_read_lock();
        list_for_each_entry_rcu(ptype, head, list) {
                if (ptype->type != type || ptype->dev || !ptype->gro_complete)
                        continue;

                err = ptype->gro_complete(skb);
                break;
        }
        rcu_read_unlock();

        if (err) {
                WARN_ON(&ptype->list == head);
                kfree_skb(skb);
                return NET_RX_SUCCESS;
        }

out:
        return netif_receive_skb(skb);
}

void napi_gro_flush(struct napi_struct *napi)
{
        struct sk_buff *skb, *next;

        for (skb = napi->gro_list; skb; skb = next) {
                next = skb->next;
                skb->next = NULL;
                napi_gro_complete(skb);
        }

        napi->gro_count = 0;
        napi->gro_list = NULL;
}
EXPORT_SYMBOL(napi_gro_flush);

enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
{
        struct sk_buff **pp = NULL;
        struct packet_type *ptype;
        __be16 type = skb->protocol;
        struct list_head *head = &ptype_base[ntohs(type) & PTYPE_HASH_MASK];
        int same_flow;
        int mac_len;
        enum gro_result ret;

        if (!(skb->dev->features & NETIF_F_GRO))
                goto normal;

        if (skb_is_gso(skb) || skb_has_frags(skb))
                goto normal;

        rcu_read_lock();
        list_for_each_entry_rcu(ptype, head, list) {
                if (ptype->type != type || ptype->dev || !ptype->gro_receive)
                        continue;

                skb_set_network_header(skb, skb_gro_offset(skb));
                mac_len = skb->network_header - skb->mac_header;
                skb->mac_len = mac_len;
                NAPI_GRO_CB(skb)->same_flow = 0;
                NAPI_GRO_CB(skb)->flush = 0;
                NAPI_GRO_CB(skb)->free = 0;

                pp = ptype->gro_receive(&napi->gro_list, skb);
                break;
        }
        rcu_read_unlock();

        if (&ptype->list == head)
                goto normal;

        same_flow = NAPI_GRO_CB(skb)->same_flow;
        ret = NAPI_GRO_CB(skb)->free ? GRO_MERGED_FREE : GRO_MERGED;

        if (pp) {
                struct sk_buff *nskb = *pp;

                *pp = nskb->next;
                nskb->next = NULL;
                napi_gro_complete(nskb);
                napi->gro_count--;
        }

        if (same_flow)
                goto ok;

        if (NAPI_GRO_CB(skb)->flush || napi->gro_count >= MAX_GRO_SKBS)
                goto normal;

        napi->gro_count++;
        NAPI_GRO_CB(skb)->count = 1;
        skb_shinfo(skb)->gso_size = skb_gro_len(skb);
        skb->next = napi->gro_list;
        napi->gro_list = skb;
        ret = GRO_HELD;

pull:
        if (skb_headlen(skb) < skb_gro_offset(skb)) {
                int grow = skb_gro_offset(skb) - skb_headlen(skb);

                BUG_ON(skb->end - skb->tail < grow);

                memcpy(skb_tail_pointer(skb), NAPI_GRO_CB(skb)->frag0, grow);

                skb->tail += grow;
                skb->data_len -= grow;

                skb_shinfo(skb)->frags[0].page_offset += grow;
                skb_shinfo(skb)->frags[0].size -= grow;

                if (unlikely(!skb_shinfo(skb)->frags[0].size)) {
                        put_page(skb_shinfo(skb)->frags[0].page);
                        memmove(skb_shinfo(skb)->frags,
                                skb_shinfo(skb)->frags + 1,
                                --skb_shinfo(skb)->nr_frags);
                }
        }

ok:
        return ret;

normal:
        ret = GRO_NORMAL;
        goto pull;
}
EXPORT_SYMBOL(dev_gro_receive);

static gro_result_t
__napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
{
        struct sk_buff *p;

        if (netpoll_rx_on(skb))
                return GRO_NORMAL;

        for (p = napi->gro_list; p; p = p->next) {
                NAPI_GRO_CB(p)->same_flow =
                        (p->dev == skb->dev) &&
                        !compare_ether_header(skb_mac_header(p),
                                              skb_gro_mac_header(skb));
                NAPI_GRO_CB(p)->flush = 0;
        }

        return dev_gro_receive(napi, skb);
}

gro_result_t napi_skb_finish(gro_result_t ret, struct sk_buff *skb)
{
        switch (ret) {
        case GRO_NORMAL:
                if (netif_receive_skb(skb))
                        ret = GRO_DROP;
                break;

        case GRO_DROP:
        case GRO_MERGED_FREE:
                kfree_skb(skb);
                break;

        case GRO_HELD:
        case GRO_MERGED:
                break;
        }

        return ret;
}
EXPORT_SYMBOL(napi_skb_finish);

void skb_gro_reset_offset(struct sk_buff *skb)
{
        NAPI_GRO_CB(skb)->data_offset = 0;
        NAPI_GRO_CB(skb)->frag0 = NULL;
        NAPI_GRO_CB(skb)->frag0_len = 0;

        if (skb->mac_header == skb->tail &&
            !PageHighMem(skb_shinfo(skb)->frags[0].page)) {
                NAPI_GRO_CB(skb)->frag0 =
                        page_address(skb_shinfo(skb)->frags[0].page) +
                        skb_shinfo(skb)->frags[0].page_offset;
                NAPI_GRO_CB(skb)->frag0_len = skb_shinfo(skb)->frags[0].size;
        }
}
EXPORT_SYMBOL(skb_gro_reset_offset);

gro_result_t napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
{
        skb_gro_reset_offset(skb);

        return napi_skb_finish(__napi_gro_receive(napi, skb), skb);
}
EXPORT_SYMBOL(napi_gro_receive);

void napi_reuse_skb(struct napi_struct *napi, struct sk_buff *skb)
{
        __skb_pull(skb, skb_headlen(skb));
        skb_reserve(skb, NET_IP_ALIGN - skb_headroom(skb));

        napi->skb = skb;
}
EXPORT_SYMBOL(napi_reuse_skb);

struct sk_buff *napi_get_frags(struct napi_struct *napi)
{
        struct sk_buff *skb = napi->skb;

        if (!skb) {
                skb = netdev_alloc_skb_ip_align(napi->dev, GRO_MAX_HEAD);
                if (skb)
                        napi->skb = skb;
        }
        return skb;
}
EXPORT_SYMBOL(napi_get_frags);

gro_result_t napi_frags_finish(struct napi_struct *napi, struct sk_buff *skb,
                               gro_result_t ret)
{
        switch (ret) {
        case GRO_NORMAL:
        case GRO_HELD:
                skb->protocol = eth_type_trans(skb, skb->dev);

                if (ret == GRO_HELD)
                        skb_gro_pull(skb, -ETH_HLEN);
                else if (netif_receive_skb(skb))
                        ret = GRO_DROP;
                break;

        case GRO_DROP:
        case GRO_MERGED_FREE:
                napi_reuse_skb(napi, skb);
                break;

        case GRO_MERGED:
                break;
        }

        return ret;
}
EXPORT_SYMBOL(napi_frags_finish);

struct sk_buff *napi_frags_skb(struct napi_struct *napi)
{
        struct sk_buff *skb = napi->skb;
        struct ethhdr *eth;
        unsigned int hlen;
        unsigned int off;

        napi->skb = NULL;

        skb_reset_mac_header(skb);
        skb_gro_reset_offset(skb);

        off = skb_gro_offset(skb);
        hlen = off + sizeof(*eth);
        eth = skb_gro_header_fast(skb, off);
        if (skb_gro_header_hard(skb, hlen)) {
                eth = skb_gro_header_slow(skb, hlen, off);
                if (unlikely(!eth)) {
                        napi_reuse_skb(napi, skb);
                        skb = NULL;
                        goto out;
                }
        }

        skb_gro_pull(skb, sizeof(*eth));

        /*
         * This works because the only protocols we care about don't require
         * special handling.  We'll fix it up properly at the end.
         */
        skb->protocol = eth->h_proto;

out:
        return skb;
}
EXPORT_SYMBOL(napi_frags_skb);

gro_result_t napi_gro_frags(struct napi_struct *napi)
{
        struct sk_buff *skb = napi_frags_skb(napi);

        if (!skb)
                return GRO_DROP;

        return napi_frags_finish(napi, skb, __napi_gro_receive(napi, skb));
}
EXPORT_SYMBOL(napi_gro_frags);

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;

                local_irq_disable();
                skb = __skb_dequeue(&queue->input_pkt_queue);
                if (!skb) {
                        __napi_complete(napi);
                        local_irq_enable();
                        break;
                }
                local_irq_enable();

                netif_receive_skb(skb);
        } 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);

void __napi_complete(struct napi_struct *n)
{
        BUG_ON(!test_bit(NAPI_STATE_SCHED, &n->state));
        BUG_ON(n->gro_list);

        list_del(&n->poll_list);
        smp_mb__before_clear_bit();
        clear_bit(NAPI_STATE_SCHED, &n->state);
}
EXPORT_SYMBOL(__napi_complete);

void napi_complete(struct napi_struct *n)
{
        unsigned long flags;

        /*
         * don't let napi dequeue from the cpu poll list
         * just in case its running on a different cpu
         */
        if (unlikely(test_bit(NAPI_STATE_NPSVC, &n->state)))
                return;

        napi_gro_flush(n);
        local_irq_save(flags);
        __napi_complete(n);
        local_irq_restore(flags);
}
EXPORT_SYMBOL(napi_complete);

void netif_napi_add(struct net_device *dev, struct napi_struct *napi,
                    int (*poll)(struct napi_struct *, int), int weight)
{
        INIT_LIST_HEAD(&napi->poll_list);
        napi->gro_count = 0;
        napi->gro_list = NULL;
        napi->skb = NULL;
        napi->poll = poll;
        napi->weight = weight;
        list_add(&napi->dev_list, &dev->napi_list);
        napi->dev = dev;
#ifdef CONFIG_NETPOLL
        spin_lock_init(&napi->poll_lock);
        napi->poll_owner = -1;
#endif
        set_bit(NAPI_STATE_SCHED, &napi->state);
}
EXPORT_SYMBOL(netif_napi_add);

void netif_napi_del(struct napi_struct *napi)
{
        struct sk_buff *skb, *next;

        list_del_init(&napi->dev_list);
        napi_free_frags(napi);

        for (skb = napi->gro_list; skb; skb = next) {
                next = skb->next;
                skb->next = NULL;
                kfree_skb(skb);
        }

        napi->gro_list = NULL;
        napi->gro_count = 0;
}
EXPORT_SYMBOL(netif_napi_del);


static void net_rx_action(struct softirq_action *h)
{
        struct list_head *list = &__get_cpu_var(softnet_data).poll_list;
        unsigned long time_limit = jiffies + 2;
        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.
                 * Allow this to run for 2 jiffies since which will allow
                 * an average latency of 1.5/HZ.
                 */
                if (unlikely(budget <= 0 || time_after(jiffies, time_limit)))
                        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);
                        trace_napi_poll(n);
                }

                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))) {
                                local_irq_enable();