/*
 * originally based on the dummy device.
 *
 * Copyright 1999, Thomas Davis, tadavis@lbl.gov.
 * Licensed under the GPL. Based on dummy.c, and eql.c devices.
 *
 * bonding.c: an Ethernet Bonding driver
 *
 * This is useful to talk to a Cisco EtherChannel compatible equipment:
 *      Cisco 5500
 *      Sun Trunking (Solaris)
 *      Alteon AceDirector Trunks
 *      Linux Bonding
 *      and probably many L2 switches ...
 *
 * How it works:
 *    ifconfig bond0 ipaddress netmask up
 *      will setup a network device, with an ip address.  No mac address
 *      will be assigned at this time.  The hw mac address will come from
 *      the first slave bonded to the channel.  All slaves will then use
 *      this hw mac address.
 *
 *    ifconfig bond0 down
 *         will release all slaves, marking them as down.
 *
 *    ifenslave bond0 eth0
 *      will attach eth0 to bond0 as a slave.  eth0 hw mac address will either
 *      a: be used as initial mac address
 *      b: if a hw mac address already is there, eth0's hw mac address
 *         will then be set from bond0.
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/interrupt.h>
#include <linux/ptrace.h>
#include <linux/ioport.h>
#include <linux/in.h>
#include <net/ip.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/timer.h>
#include <linux/socket.h>
#include <linux/ctype.h>
#include <linux/inet.h>
#include <linux/bitops.h>
#include <linux/io.h>
#include <asm/dma.h>
#include <linux/uaccess.h>
#include <linux/errno.h>
#include <linux/netdevice.h>
#include <linux/inetdevice.h>
#include <linux/igmp.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <linux/rtnetlink.h>
#include <linux/smp.h>
#include <linux/if_ether.h>
#include <net/arp.h>
#include <linux/mii.h>
#include <linux/ethtool.h>
#include <linux/if_vlan.h>
#include <linux/if_bonding.h>
#include <linux/jiffies.h>
#include <linux/preempt.h>
#include <net/route.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include <net/pkt_sched.h>
#include "bonding.h"
#include "bond_3ad.h"
#include "bond_alb.h"

/*---------------------------- Module parameters ----------------------------*/

/* monitor all links that often (in milliseconds). <=0 disables monitoring */
#define BOND_LINK_MON_INTERV    0
#define BOND_LINK_ARP_INTERV    0

static int max_bonds    = BOND_DEFAULT_MAX_BONDS;
static int tx_queues    = BOND_DEFAULT_TX_QUEUES;
static int num_peer_notif = 1;
static int miimon       = BOND_LINK_MON_INTERV;
static int updelay;
static int downdelay;
static int use_carrier  = 1;
static char *mode;
static char *primary;
static char *primary_reselect;
static char *lacp_rate;
static int min_links;
static char *ad_select;
static char *xmit_hash_policy;
static int arp_interval = BOND_LINK_ARP_INTERV;
static char *arp_ip_target[BOND_MAX_ARP_TARGETS];
static char *arp_validate;
static char *fail_over_mac;
static int all_slaves_active = 0;
static struct bond_params bonding_defaults;
static int resend_igmp = BOND_DEFAULT_RESEND_IGMP;

module_param(max_bonds, int, 0);
MODULE_PARM_DESC(max_bonds, "Max number of bonded devices");
module_param(tx_queues, int, 0);
MODULE_PARM_DESC(tx_queues, "Max number of transmit queues (default = 16)");
module_param_named(num_grat_arp, num_peer_notif, int, 0644);
MODULE_PARM_DESC(num_grat_arp, "Number of peer notifications to send on "
                               "failover event (alias of num_unsol_na)");
module_param_named(num_unsol_na, num_peer_notif, int, 0644);
MODULE_PARM_DESC(num_unsol_na, "Number of peer notifications to send on "
                               "failover event (alias of num_grat_arp)");
module_param(miimon, int, 0);
MODULE_PARM_DESC(miimon, "Link check interval in milliseconds");
module_param(updelay, int, 0);
MODULE_PARM_DESC(updelay, "Delay before considering link up, in milliseconds");
module_param(downdelay, int, 0);
MODULE_PARM_DESC(downdelay, "Delay before considering link down, "
                            "in milliseconds");
module_param(use_carrier, int, 0);
MODULE_PARM_DESC(use_carrier, "Use netif_carrier_ok (vs MII ioctls) in miimon; "
                              "0 for off, 1 for on (default)");
module_param(mode, charp, 0);
MODULE_PARM_DESC(mode, "Mode of operation; 0 for balance-rr, "
                       "1 for active-backup, 2 for balance-xor, "
                       "3 for broadcast, 4 for 802.3ad, 5 for balance-tlb, "
                       "6 for balance-alb");
module_param(primary, charp, 0);
MODULE_PARM_DESC(primary, "Primary network device to use");
module_param(primary_reselect, charp, 0);
MODULE_PARM_DESC(primary_reselect, "Reselect primary slave "
                                   "once it comes up; "
                                   "0 for always (default), "
                                   "1 for only if speed of primary is "
                                   "better, "
                                   "2 for only on active slave "
                                   "failure");
module_param(lacp_rate, charp, 0);
MODULE_PARM_DESC(lacp_rate, "LACPDU tx rate to request from 802.3ad partner; "
                            "0 for slow, 1 for fast");
module_param(ad_select, charp, 0);
MODULE_PARM_DESC(ad_select, "803.ad aggregation selection logic; "
                            "0 for stable (default), 1 for bandwidth, "
                            "2 for count");
module_param(min_links, int, 0);
MODULE_PARM_DESC(min_links, "Minimum number of available links before turning on carrier");

module_param(xmit_hash_policy, charp, 0);
MODULE_PARM_DESC(xmit_hash_policy, "balance-xor and 802.3ad hashing method; "
                                   "0 for layer 2 (default), 1 for layer 3+4, "
                                   "2 for layer 2+3");
module_param(arp_interval, int, 0);
MODULE_PARM_DESC(arp_interval, "arp interval in milliseconds");
module_param_array(arp_ip_target, charp, NULL, 0);
MODULE_PARM_DESC(arp_ip_target, "arp targets in n.n.n.n form");
module_param(arp_validate, charp, 0);
MODULE_PARM_DESC(arp_validate, "validate src/dst of ARP probes; "
                               "0 for none (default), 1 for active, "
                               "2 for backup, 3 for all");
module_param(fail_over_mac, charp, 0);
MODULE_PARM_DESC(fail_over_mac, "For active-backup, do not set all slaves to "
                                "the same MAC; 0 for none (default), "
                                "1 for active, 2 for follow");
module_param(all_slaves_active, int, 0);
MODULE_PARM_DESC(all_slaves_active, "Keep all frames received on an interface"
                                     "by setting active flag for all slaves; "
                                     "0 for never (default), 1 for always.");
module_param(resend_igmp, int, 0);
MODULE_PARM_DESC(resend_igmp, "Number of IGMP membership reports to send on "
                              "link failure");

/*----------------------------- Global variables ----------------------------*/

#ifdef CONFIG_NET_POLL_CONTROLLER
atomic_t netpoll_block_tx = ATOMIC_INIT(0);
#endif

int bond_net_id __read_mostly;

static __be32 arp_target[BOND_MAX_ARP_TARGETS];
static int arp_ip_count;
static int bond_mode    = BOND_MODE_ROUNDROBIN;
static int xmit_hashtype = BOND_XMIT_POLICY_LAYER2;
static int lacp_fast;

const struct bond_parm_tbl bond_lacp_tbl[] = {
{       "slow",         AD_LACP_SLOW},
{       "fast",         AD_LACP_FAST},
{       NULL,           -1},
};

const struct bond_parm_tbl bond_mode_tbl[] = {
{       "balance-rr",           BOND_MODE_ROUNDROBIN},
{       "active-backup",        BOND_MODE_ACTIVEBACKUP},
{       "balance-xor",          BOND_MODE_XOR},
{       "broadcast",            BOND_MODE_BROADCAST},
{       "802.3ad",              BOND_MODE_8023AD},
{       "balance-tlb",          BOND_MODE_TLB},
{       "balance-alb",          BOND_MODE_ALB},
{       NULL,                   -1},
};

const struct bond_parm_tbl xmit_hashtype_tbl[] = {
{       "layer2",               BOND_XMIT_POLICY_LAYER2},
{       "layer3+4",             BOND_XMIT_POLICY_LAYER34},
{       "layer2+3",             BOND_XMIT_POLICY_LAYER23},
{       NULL,                   -1},
};

const struct bond_parm_tbl arp_validate_tbl[] = {
{       "none",                 BOND_ARP_VALIDATE_NONE},
{       "active",               BOND_ARP_VALIDATE_ACTIVE},
{       "backup",               BOND_ARP_VALIDATE_BACKUP},
{       "all",                  BOND_ARP_VALIDATE_ALL},
{       NULL,                   -1},
};

const struct bond_parm_tbl fail_over_mac_tbl[] = {
{       "none",                 BOND_FOM_NONE},
{       "active",               BOND_FOM_ACTIVE},
{       "follow",               BOND_FOM_FOLLOW},
{       NULL,                   -1},
};

const struct bond_parm_tbl pri_reselect_tbl[] = {
{       "always",               BOND_PRI_RESELECT_ALWAYS},
{       "better",               BOND_PRI_RESELECT_BETTER},
{       "failure",              BOND_PRI_RESELECT_FAILURE},
{       NULL,                   -1},
};

struct bond_parm_tbl ad_select_tbl[] = {
{       "stable",       BOND_AD_STABLE},
{       "bandwidth",    BOND_AD_BANDWIDTH},
{       "count",        BOND_AD_COUNT},
{       NULL,           -1},
};

/*-------------------------- Forward declarations ---------------------------*/

static int bond_init(struct net_device *bond_dev);
static void bond_uninit(struct net_device *bond_dev);

/*---------------------------- General routines -----------------------------*/

const char *bond_mode_name(int mode)
{
        static const char *names[] = {
                [BOND_MODE_ROUNDROBIN] = "load balancing (round-robin)",
                [BOND_MODE_ACTIVEBACKUP] = "fault-tolerance (active-backup)",
                [BOND_MODE_XOR] = "load balancing (xor)",
                [BOND_MODE_BROADCAST] = "fault-tolerance (broadcast)",
                [BOND_MODE_8023AD] = "IEEE 802.3ad Dynamic link aggregation",
                [BOND_MODE_TLB] = "transmit load balancing",
                [BOND_MODE_ALB] = "adaptive load balancing",
        };

        if (mode < 0 || mode > BOND_MODE_ALB)
                return "unknown";

        return names[mode];
}

/*---------------------------------- VLAN -----------------------------------*/

/**
 * bond_add_vlan - add a new vlan id on bond
 * @bond: bond that got the notification
 * @vlan_id: the vlan id to add
 *
 * Returns -ENOMEM if allocation failed.
 */
static int bond_add_vlan(struct bonding *bond, unsigned short vlan_id)
{
        struct vlan_entry *vlan;

        pr_debug("bond: %s, vlan id %d\n",
                 (bond ? bond->dev->name : "None"), vlan_id);

        vlan = kzalloc(sizeof(struct vlan_entry), GFP_KERNEL);
        if (!vlan)
                return -ENOMEM;

        INIT_LIST_HEAD(&vlan->vlan_list);
        vlan->vlan_id = vlan_id;

        write_lock_bh(&bond->lock);

        list_add_tail(&vlan->vlan_list, &bond->vlan_list);

        write_unlock_bh(&bond->lock);

        pr_debug("added VLAN ID %d on bond %s\n", vlan_id, bond->dev->name);

        return 0;
}

/**
 * bond_del_vlan - delete a vlan id from bond
 * @bond: bond that got the notification
 * @vlan_id: the vlan id to delete
 *
 * returns -ENODEV if @vlan_id was not found in @bond.
 */
static int bond_del_vlan(struct bonding *bond, unsigned short vlan_id)
{
        struct vlan_entry *vlan;
        int res = -ENODEV;

        pr_debug("bond: %s, vlan id %d\n", bond->dev->name, vlan_id);

        block_netpoll_tx();
        write_lock_bh(&bond->lock);

        list_for_each_entry(vlan, &bond->vlan_list, vlan_list) {
                if (vlan->vlan_id == vlan_id) {
                        list_del(&vlan->vlan_list);

                        if (bond_is_lb(bond))
                                bond_alb_clear_vlan(bond, vlan_id);

                        pr_debug("removed VLAN ID %d from bond %s\n",
                                 vlan_id, bond->dev->name);

                        kfree(vlan);

                        res = 0;
                        goto out;
                }
        }

        pr_debug("couldn't find VLAN ID %d in bond %s\n",
                 vlan_id, bond->dev->name);

out:
        write_unlock_bh(&bond->lock);
        unblock_netpoll_tx();
        return res;
}

/**
 * bond_next_vlan - safely skip to the next item in the vlans list.
 * @bond: the bond we're working on
 * @curr: item we're advancing from
 *
 * Returns %NULL if list is empty, bond->next_vlan if @curr is %NULL,
 * or @curr->next otherwise (even if it is @curr itself again).
 *
 * Caller must hold bond->lock
 */
struct vlan_entry *bond_next_vlan(struct bonding *bond, struct vlan_entry *curr)
{
        struct vlan_entry *next, *last;

        if (list_empty(&bond->vlan_list))
                return NULL;

        if (!curr) {
                next = list_entry(bond->vlan_list.next,
                                  struct vlan_entry, vlan_list);
        } else {
                last = list_entry(bond->vlan_list.prev,
                                  struct vlan_entry, vlan_list);
                if (last == curr) {
                        next = list_entry(bond->vlan_list.next,
                                          struct vlan_entry, vlan_list);
                } else {
                        next = list_entry(curr->vlan_list.next,
                                          struct vlan_entry, vlan_list);
                }
        }

        return next;
}

/**
 * bond_dev_queue_xmit - Prepare skb for xmit.
 *
 * @bond: bond device that got this skb for tx.
 * @skb: hw accel VLAN tagged skb to transmit
 * @slave_dev: slave that is supposed to xmit this skbuff
 */
int bond_dev_queue_xmit(struct bonding *bond, struct sk_buff *skb,
                        struct net_device *slave_dev)
{
        skb->dev = slave_dev;

        BUILD_BUG_ON(sizeof(skb->queue_mapping) !=
                     sizeof(qdisc_skb_cb(skb)->slave_dev_queue_mapping));
        skb->queue_mapping = qdisc_skb_cb(skb)->slave_dev_queue_mapping;

        if (unlikely(netpoll_tx_running(bond->dev)))
                bond_netpoll_send_skb(bond_get_slave_by_dev(bond, slave_dev), skb);
        else
                dev_queue_xmit(skb);

        return 0;
}

/*
 * In the following 2 functions, bond_vlan_rx_add_vid and bond_vlan_rx_kill_vid,
 * We don't protect the slave list iteration with a lock because:
 * a. This operation is performed in IOCTL context,
 * b. The operation is protected by the RTNL semaphore in the 8021q code,
 * c. Holding a lock with BH disabled while directly calling a base driver
 *    entry point is generally a BAD idea.
 *
 * The design of synchronization/protection for this operation in the 8021q
 * module is good for one or more VLAN devices over a single physical device
 * and cannot be extended for a teaming solution like bonding, so there is a
 * potential race condition here where a net device from the vlan group might
 * be referenced (either by a base driver or the 8021q code) while it is being
 * removed from the system. However, it turns out we're not making matters
 * worse, and if it works for regular VLAN usage it will work here too.
*/

/**
 * bond_vlan_rx_add_vid - Propagates adding an id to slaves
 * @bond_dev: bonding net device that got called
 * @vid: vlan id being added
 */
static int bond_vlan_rx_add_vid(struct net_device *bond_dev, uint16_t vid)
{
        struct bonding *bond = netdev_priv(bond_dev);
        struct slave *slave, *stop_at;
        int i, res;

        bond_for_each_slave(bond, slave, i) {
                res = vlan_vid_add(slave->dev, vid);
                if (res)
                        goto unwind;
        }

        res = bond_add_vlan(bond, vid);
        if (res) {
                pr_err("%s: Error: Failed to add vlan id %d\n",
                       bond_dev->name, vid);
                return res;
        }

        return 0;

unwind:
        /* unwind from head to the slave that failed */
        stop_at = slave;
        bond_for_each_slave_from_to(bond, slave, i, bond->first_slave, stop_at)
                vlan_vid_del(slave->dev, vid);

        return res;
}

/**
 * bond_vlan_rx_kill_vid - Propagates deleting an id to slaves
 * @bond_dev: bonding net device that got called
 * @vid: vlan id being removed
 */
static int bond_vlan_rx_kill_vid(struct net_device *bond_dev, uint16_t vid)
{
        struct bonding *bond = netdev_priv(bond_dev);
        struct slave *slave;
        int i, res;

        bond_for_each_slave(bond, slave, i)
                vlan_vid_del(slave->dev, vid);

        res = bond_del_vlan(bond, vid);
        if (res) {
                pr_err("%s: Error: Failed to remove vlan id %d\n",
                       bond_dev->name, vid);
                return res;
        }

        return 0;
}

static void bond_add_vlans_on_slave(struct bonding *bond, struct net_device *slave_dev)
{
        struct vlan_entry *vlan;
        int res;

        list_for_each_entry(vlan, &bond->vlan_list, vlan_list) {
                res = vlan_vid_add(slave_dev, vlan->vlan_id);
                if (res)
                        pr_warning("%s: Failed to add vlan id %d to device %s\n",
                                   bond->dev->name, vlan->vlan_id,
                                   slave_dev->name);
        }
}

static void bond_del_vlans_from_slave(struct bonding *bond,
                                      struct net_device *slave_dev)
{
        struct vlan_entry *vlan;

        list_for_each_entry(vlan, &bond->vlan_list, vlan_list) {
                if (!vlan->vlan_id)
                        continue;
                vlan_vid_del(slave_dev, vlan->vlan_id);
        }
}

/*------------------------------- Link status -------------------------------*/

/*
 * Set the carrier state for the master according to the state of its
 * slaves.  If any slaves are up, the master is up.  In 802.3ad mode,
 * do special 802.3ad magic.
 *
 * Returns zero if carrier state does not change, nonzero if it does.
 */
static int bond_set_carrier(struct bonding *bond)
{
        struct slave *slave;
        int i;

        if (bond->slave_cnt == 0)
                goto down;

        if (bond->params.mode == BOND_MODE_8023AD)
                return bond_3ad_set_carrier(bond);

        bond_for_each_slave(bond, slave, i) {
                if (slave->link == BOND_LINK_UP) {
                        if (!netif_carrier_ok(bond->dev)) {
                                netif_carrier_on(bond->dev);
                                return 1;
                        }
                        return 0;
                }
        }

down:
        if (netif_carrier_ok(bond->dev)) {
                netif_carrier_off(bond->dev);
                return 1;
        }
        return 0;
}

/*
 * Get link speed and duplex from the slave's base driver
 * using ethtool. If for some reason the call fails or the
 * values are invalid, set speed and duplex to -1,
 * and return.
 */
static void bond_update_speed_duplex(struct slave *slave)
{
        struct net_device *slave_dev = slave->dev;
        struct ethtool_cmd ecmd;
        u32 slave_speed;
        int res;

        slave->speed = SPEED_UNKNOWN;
        slave->duplex = DUPLEX_UNKNOWN;

        res = __ethtool_get_settings(slave_dev, &ecmd);
        if (res < 0)
                return;

        slave_speed = ethtool_cmd_speed(&ecmd);
        if (slave_speed == 0 || slave_speed == ((__u32) -1))
                return;

        switch (ecmd.duplex) {
        case DUPLEX_FULL:
        case DUPLEX_HALF:
                break;
        default:
                return;
        }

        slave->speed = slave_speed;
        slave->duplex = ecmd.duplex;

        return;
}

/*
 * if <dev> supports MII link status reporting, check its link status.
 *
 * We either do MII/ETHTOOL ioctls, or check netif_carrier_ok(),
 * depending upon the setting of the use_carrier parameter.
 *
 * Return either BMSR_LSTATUS, meaning that the link is up (or we
 * can't tell and just pretend it is), or 0, meaning that the link is
 * down.
 *
 * If reporting is non-zero, instead of faking link up, return -1 if
 * both ETHTOOL and MII ioctls fail (meaning the device does not
 * support them).  If use_carrier is set, return whatever it says.
 * It'd be nice if there was a good way to tell if a driver supports
 * netif_carrier, but there really isn't.
 */
static int bond_check_dev_link(struct bonding *bond,
                               struct net_device *slave_dev, int reporting)
{
        const struct net_device_ops *slave_ops = slave_dev->netdev_ops;
        int (*ioctl)(struct net_device *, struct ifreq *, int);
        struct ifreq ifr;
        struct mii_ioctl_data *mii;

        if (!reporting && !netif_running(slave_dev))
                return 0;

        if (bond->params.use_carrier)
                return netif_carrier_ok(slave_dev) ? BMSR_LSTATUS : 0;

        /* Try to get link status using Ethtool first. */
        if (slave_dev->ethtool_ops->get_link)
                return slave_dev->ethtool_ops->get_link(slave_dev) ?
                        BMSR_LSTATUS : 0;

        /* Ethtool can't be used, fallback to MII ioctls. */
        ioctl = slave_ops->ndo_do_ioctl;
        if (ioctl) {
                /* TODO: set pointer to correct ioctl on a per team member */
                /*       bases to make this more efficient. that is, once  */
                /*       we determine the correct ioctl, we will always    */
                /*       call it and not the others for that team          */
                /*       member.                                           */

                /*
                 * We cannot assume that SIOCGMIIPHY will also read a
                 * register; not all network drivers (e.g., e100)
                 * support that.
                 */

                /* Yes, the mii is overlaid on the ifreq.ifr_ifru */
                strncpy(ifr.ifr_name, slave_dev->name, IFNAMSIZ);
                mii = if_mii(&ifr);
                if (IOCTL(slave_dev, &ifr, SIOCGMIIPHY) == 0) {
                        mii->reg_num = MII_BMSR;
                        if (IOCTL(slave_dev, &ifr, SIOCGMIIREG) == 0)
                                return mii->val_out & BMSR_LSTATUS;
                }
        }

        /*
         * If reporting, report that either there's no dev->do_ioctl,
         * or both SIOCGMIIREG and get_link failed (meaning that we
         * cannot report link status).  If not reporting, pretend
         * we're ok.
         */
        return reporting ? -1 : BMSR_LSTATUS;
}

/*----------------------------- Multicast list ------------------------------*/

/*
 * Push the promiscuity flag down to appropriate slaves
 */
static int bond_set_promiscuity(struct bonding *bond, int inc)
{
        int err = 0;
        if (USES_PRIMARY(bond->params.mode)) {
                /* write lock already acquired */
                if (bond->curr_active_slave) {
                        err = dev_set_promiscuity(bond->curr_active_slave->dev,
                                                  inc);
                }
        } else {
                struct slave *slave;
                int i;
                bond_for_each_slave(bond, slave, i) {
                        err = dev_set_promiscuity(slave->dev, inc);
                        if (err)
                                return err;
                }
        }
        return err;
}

/*
 * Push the allmulti flag down to all slaves
 */
static int bond_set_allmulti(struct bonding *bond, int inc)
{
        int err = 0;
        if (USES_PRIMARY(bond->params.mode)) {
                /* write lock already acquired */
                if (bond->curr_active_slave) {
                        err = dev_set_allmulti(bond->curr_active_slave->dev,
                                               inc);
                }
        } else {
                struct slave *slave;
                int i;
                bond_for_each_slave(bond, slave, i) {
                        err = dev_set_allmulti(slave->dev, inc);
                        if (err)
                                return err;
                }
        }
        return err;
}

/*
 * Add a Multicast address to slaves
 * according to mode
 */
static void bond_mc_add(struct bonding *bond, void *addr)
{
        if (USES_PRIMARY(bond->params.mode)) {
                /* write lock already acquired */
                if (bond->curr_active_slave)
                        dev_mc_add(bond->curr_active_slave->dev, addr);
        } else {
                struct slave *slave;
                int i;

                bond_for_each_slave(bond, slave, i)
                        dev_mc_add(slave->dev, addr);
        }
}

/*
 * Remove a multicast address from slave
 * according to mode
 */
static void bond_mc_del(struct bonding *bond, void *addr)
{
        if (USES_PRIMARY(bond->params.mode)) {
                /* write lock already acquired */
                if (bond->curr_active_slave)
                        dev_mc_del(bond->curr_active_slave->dev, addr);
        } else {
                struct slave *slave;
                int i;
                bond_for_each_slave(bond, slave, i) {
                        dev_mc_del(slave->dev, addr);
                }
        }
}


static void __bond_resend_igmp_join_requests(struct net_device *dev)
{
        struct in_device *in_dev;

        rcu_read_lock();
        in_dev = __in_dev_get_rcu(dev);
        if (in_dev)
                ip_mc_rejoin_groups(in_dev);
        rcu_read_unlock();
}

/*
 * Retrieve the list of registered multicast addresses for the bonding
 * device and retransmit an IGMP JOIN request to the current active
 * slave.
 */
static void bond_resend_igmp_join_requests(struct bonding *bond)
{
        struct net_device *bond_dev, *vlan_dev, *master_dev;
        struct vlan_entry *vlan;

        read_lock(&bond->lock);

        bond_dev = bond->dev;

        /* rejoin all groups on bond device */
        __bond_resend_igmp_join_requests(bond_dev);

        /*
         * if bond is enslaved to a bridge,
         * then rejoin all groups on its master
         */
        master_dev = bond_dev->master;
        if (master_dev)
                if ((master_dev->priv_flags & IFF_EBRIDGE)
                        && (bond_dev->priv_flags & IFF_BRIDGE_PORT))
                        __bond_resend_igmp_join_requests(master_dev);

        /* rejoin all groups on vlan devices */
        list_for_each_entry(vlan, &bond->vlan_list, vlan_list) {
                rcu_read_lock();
                vlan_dev = __vlan_find_dev_deep(bond_dev,
                                                vlan->vlan_id);
                rcu_read_unlock();
                if (vlan_dev)
                        __bond_resend_igmp_join_requests(vlan_dev);
        }

        if (--bond->igmp_retrans > 0)
                queue_delayed_work(bond->wq, &bond->mcast_work, HZ/5);

        read_unlock(&bond->lock);
}

static void bond_resend_igmp_join_requests_delayed(struct work_struct *work)
{
        struct bonding *bond = container_of(work, struct bonding,
                                            mcast_work.work);
        bond_resend_igmp_join_requests(bond);
}

/*
 * flush all members of flush->mc_list from device dev->mc_list
 */
static void bond_mc_list_flush(struct net_device *bond_dev,
                               struct net_device *slave_dev)
{
        struct bonding *bond = netdev_priv(bond_dev);
        struct netdev_hw_addr *ha;

        netdev_for_each_mc_addr(ha, bond_dev)
                dev_mc_del(slave_dev, ha->addr);

        if (bond->params.mode == BOND_MODE_8023AD) {
                /* del lacpdu mc addr from mc list */
                u8 lacpdu_multicast[ETH_ALEN] = MULTICAST_LACPDU_ADDR;

                dev_mc_del(slave_dev, lacpdu_multicast);
        }
}

/*--------------------------- Active slave change ---------------------------*/

/*
 * Update the mc list and multicast-related flags for the new and
 * old active slaves (if any) according to the multicast mode, and
 * promiscuous flags unconditionally.
 */
static void bond_mc_swap(struct bonding *bond, struct slave *new_active,
                         struct slave *old_active)
{
        struct netdev_hw_addr *ha;

        if (!USES_PRIMARY(bond->params.mode))
                /* nothing to do -  mc list is already up-to-date on
                 * all slaves
                 */
                return;

        if (old_active) {
                if (bond->dev->flags & IFF_PROMISC)
                        dev_set_promiscuity(old_active->dev, -1);

                if (bond->dev->flags & IFF_ALLMULTI)
                        dev_set_allmulti(old_active->dev, -1);

                netdev_for_each_mc_addr(ha, bond->dev)
                        dev_mc_del(old_active->dev, ha->addr);
        }

        if (new_active) {
                /* FIXME: Signal errors upstream. */
                if (bond->dev->flags & IFF_PROMISC)
                        dev_set_promiscuity(new_active->dev, 1);

                if (bond->dev->flags & IFF_ALLMULTI)
                        dev_set_allmulti(new_active->dev, 1);

                netdev_for_each_mc_addr(ha, bond->dev)
                        dev_mc_add(new_active->dev, ha->addr);
        }
}

/*
 * bond_do_fail_over_mac
 *
 * Perform special MAC address swapping for fail_over_mac settings
 *
 * Called with RTNL, bond->lock for read, curr_slave_lock for write_bh.
 */
static void bond_do_fail_over_mac(struct bonding *bond,
                                  struct slave *new_active,
                                  struct slave *old_active)
        __releases(&bond->curr_slave_lock)
        __releases(&bond->lock)
        __acquires(&bond->lock)
        __acquires(&bond->curr_slave_lock)
{
        u8 tmp_mac[ETH_ALEN];
        struct sockaddr saddr;
        int rv;

        switch (bond->params.fail_over_mac) {
        case BOND_FOM_ACTIVE:
                if (new_active) {
                        memcpy(bond->dev->dev_addr,  new_active->dev->dev_addr,
                               new_active->dev->addr_len);
                        write_unlock_bh(&bond->curr_slave_lock);
                        read_unlock(&bond->lock);
                        call_netdevice_notifiers(NETDEV_CHANGEADDR, bond->dev);
                        read_lock(&bond->lock);
                        write_lock_bh(&bond->curr_slave_lock);
                }
                break;
        case BOND_FOM_FOLLOW:
                /*
                 * if new_active && old_active, swap them
                 * if just old_active, do nothing (going to no active slave)
                 * if just new_active, set new_active to bond's MAC
                 */
                if (!new_active)
                        return;

                write_unlock_bh(&bond->curr_slave_lock);
                read_unlock(&bond->lock);

                if (old_active) {
                        memcpy(tmp_mac, new_active->dev->dev_addr, ETH_ALEN);
                        memcpy(saddr.sa_data, old_active->dev->dev_addr,
                               ETH_ALEN);
                        saddr.sa_family = new_active->dev->type;
                } else {
                        memcpy(saddr.sa_data, bond->dev->dev_addr, ETH_ALEN);
                        saddr.sa_family = bond->dev->type;
                }

                rv = dev_set_mac_address(new_active->dev, &saddr);
                if (rv) {
                        pr_err("%s: Error %d setting MAC of slave %s\n",
                               bond->dev->name, -rv, new_active->dev->name);
                        goto out;
                }

                if (!old_active)
                        goto out;

                memcpy(saddr.sa_data, tmp_mac, ETH_ALEN);
                saddr.sa_family = old_active->dev->type;

                rv = dev_set_mac_address(old_active->dev, &saddr);
                if (rv)
                        pr_err("%s: Error %d setting MAC of slave %s\n",
                               bond->dev->name, -rv, new_active->dev->name);
out:
                read_lock(&bond->lock);
                write_lock_bh(&bond->curr_slave_lock);
                break;
        default:
                pr_err("%s: bond_do_fail_over_mac impossible: bad policy %d\n",
                       bond->dev->name, bond->params.fail_over_mac);
                break;
        }

}

static bool bond_should_change_active(struct bonding *bond)
{
        struct slave *prim = bond->primary_slave;
        struct slave *curr = bond->curr_active_slave;

        if (!prim || !curr || curr->link != BOND_LINK_UP)
                return true;
        if (bond->force_primary) {
                bond->force_primary = false;
                return true;
        }
        if (bond->params.primary_reselect == BOND_PRI_RESELECT_BETTER &&
            (prim->speed < curr->speed ||
             (prim->speed == curr->speed && prim->duplex <= curr->duplex)))
                return false;
        if (bond->params.primary_reselect == BOND_PRI_RESELECT_FAILURE)
                return false;
        return true;
}

/**
 * find_best_interface - select the best available slave to be the active one
 * @bond: our bonding struct
 *
 * Warning: Caller must hold curr_slave_lock for writing.
 */
static struct slave *bond_find_best_slave(struct bonding *bond)
{
        struct slave *new_active, *old_active;
        struct slave *bestslave = NULL;
        int mintime = bond->params.updelay;
        int i;

        new_active = bond->curr_active_slave;

        if (!new_active) { /* there were no active slaves left */
                if (bond->slave_cnt > 0)   /* found one slave */
                        new_active = bond->first_slave;
                else
                        return NULL; /* still no slave, return NULL */
        }

        if ((bond->primary_slave) &&
            bond->primary_slave->link == BOND_LINK_UP &&
            bond_should_change_active(bond)) {
                new_active = bond->primary_slave;
        }

        /* remember where to stop iterating over the slaves */
        old_active = new_active;

        bond_for_each_slave_from(bond, new_active, i, old_active) {
                if (new_active->link == BOND_LINK_UP) {
                        return new_active;
                } else if (new_active->link == BOND_LINK_BACK &&
                           IS_UP(new_active->dev)) {
                        /* link up, but waiting for stabilization */
                        if (new_active->delay < mintime) {
                                mintime = new_active->delay;
                                bestslave = new_active;
                        }
                }
        }

        return bestslave;
}

static bool bond_should_notify_peers(struct bonding *bond)
{
        struct slave *slave = bond->curr_active_slave;

        pr_debug("bond_should_notify_peers: bond %s slave %s\n",
                 bond->dev->name, slave ? slave->dev->name : "NULL");

        if (!slave || !bond->send_peer_notif ||
            test_bit(__LINK_STATE_LINKWATCH_PENDING, &slave->dev->state))
                return false;

        bond->send_peer_notif--;
        return true;
}

/**
 * change_active_interface - change the active slave into the specified one
 * @bond: our bonding struct
 * @new: the new slave to make the active one
 *
 * Set the new slave to the bond's settings and unset them on the old
 * curr_active_slave.
 * Setting include flags, mc-list, promiscuity, allmulti, etc.
 *
 * If @new's link state is %BOND_LINK_BACK we'll set it to %BOND_LINK_UP,
 * because it is apparently the best available slave we have, even though its
 * updelay hasn't timed out yet.
 *
 * If new_active is not NULL, caller must hold bond->lock for read and
 * curr_slave_lock for write_bh.
 */
void bond_change_active_slave(struct bonding *bond, struct slave *new_active)
{
        struct slave *old_active = bond->curr_active_slave;

        if (old_active == new_active)
                return;

        if (new_active) {
                new_active->jiffies = jiffies;

                if (new_active->link == BOND_LINK_BACK) {
                        if (USES_PRIMARY(bond->params.mode)) {
                                pr_info("%s: making interface %s the new active one %d ms earlier.\n",
                                        bond->dev->name, new_active->dev->name,
                                        (bond->params.updelay - new_active->delay) * bond->params.miimon);
                        }

                        new_active->delay = 0;
                        new_active->link = BOND_LINK_UP;

                        if (bond->params.mode == BOND_MODE_8023AD)
                                bond_3ad_handle_link_change(new_active, BOND_LINK_UP);

                        if (bond_is_lb(bond))
                                bond_alb_handle_link_change(bond, new_active, BOND_LINK_UP);
                } else {
                        if (USES_PRIMARY(bond->params.mode)) {
                                pr_info("%s: making interface %s the new active one.\n",
                                        bond->dev->name, new_active->dev->name);
                        }
                }
        }

        if (USES_PRIMARY(bond->params.mode))
                bond_mc_swap(bond, new_active, old_active);

        if (bond_is_lb(bond)) {
                bond_alb_handle_active_change(bond, new_active);
                if (old_active)
                        bond_set_slave_inactive_flags(old_active);
                if (new_active)
                        bond_set_slave_active_flags(new_active);
        } else {
                bond->curr_active_slave = new_active;
        }

        if (bond->params.mode == BOND_MODE_ACTIVEBACKUP) {
                if (old_active)
                        bond_set_slave_inactive_flags(old_active);

                if (new_active) {
                        bool should_notify_peers = false;

                        bond_set_slave_active_flags(new_active);

                        if (bond->params.fail_over_mac)
                                bond_do_fail_over_mac(bond, new_active,
                                                      old_active);

                        if (netif_running(bond->dev)) {
                                bond->send_peer_notif =
                                        bond->params.num_peer_notif;
                                should_notify_peers =
                                        bond_should_notify_peers(bond);
                        }

                        write_unlock_bh(&bond->curr_slave_lock);
                        read_unlock(&bond->lock);

                        call_netdevice_notifiers(NETDEV_BONDING_FAILOVER, bond->dev);
                        if (should_notify_peers)
                                call_netdevice_notifiers(NETDEV_NOTIFY_PEERS,
                                                         bond->dev);

                        read_lock(&bond->lock);
                        write_lock_bh(&bond->curr_slave_lock);
                }
        }

        /* resend IGMP joins since active slave has changed or
         * all were sent on curr_active_slave.
         * resend only if bond is brought up with the affected
         * bonding modes and the retransmission is enabled */
        if (netif_running(bond->dev) && (bond->params.resend_igmp > 0) &&
            ((USES_PRIMARY(bond->params.mode) && new_active) ||
             bond->params.mode == BOND_MODE_ROUNDROBIN)) {
                bond->igmp_retrans = bond->params.resend_igmp;
                queue_delayed_work(bond->wq, &bond->mcast_work, 0);
        }
}

/**
 * bond_select_active_slave - select a new active slave, if needed
 * @bond: our bonding struct
 *
 * This functions should be called when one of the following occurs:
 * - The old curr_active_slave has been released or lost its link.
 * - The primary_slave has got its link back.
 * - A slave has got its link back and there's no old curr_active_slave.
 *
 * Caller must hold bond->lock for read and curr_slave_lock for write_bh.
 */
void bond_select_active_slave(struct bonding *bond)
{
        struct slave *best_slave;
        int rv;

        best_slave = bond_find_best_slave(bond);
        if (best_slave != bond->curr_active_slave) {
                bond_change_active_slave(bond, best_slave);
                rv = bond_set_carrier(bond);
                if (!rv)
                        return;

                if (netif_carrier_ok(bond->dev)) {
                        pr_info("%s: first active interface up!\n",
                                bond->dev->name);
                } else {
                        pr_info("%s: now running without any active interface !\n",
                                bond->dev->name);
                }
        }
}

/*--------------------------- slave list handling ---------------------------*/

/*
 * This function attaches the slave to the end of list.
 *
 * bond->lock held for writing by caller.
 */
static void bond_attach_slave(struct bonding *bond, struct slave *new_slave)
{
        if (bond->first_slave == NULL) { /* attaching the first slave */
                new_slave->next = new_slave;
                new_slave->prev = new_slave;
                bond->first_slave = new_slave;
        } else {
                new_slave->next = bond->first_slave;
                new_slave->prev = bond->first_slave->prev;
                new_slave->next->prev = new_slave;
                new_slave->prev->next = new_slave;
        }

        bond->slave_cnt++;
}

/*
 * This function detaches the slave from the list.
 * WARNING: no check is made to verify if the slave effectively
 * belongs to <bond>.
 * Nothing is freed on return, structures are just unchained.
 * If any slave pointer in bond was pointing to <slave>,
 * it should be changed by the calling function.
 *
 * bond->lock held for writing by caller.
 */
static void bond_detach_slave(struct bonding *bond, struct slave *slave)
{
        if (slave->next)
                slave->next->prev = slave->prev;

        if (slave->prev)
                slave->prev->next = slave->next;

        if (bond->first_slave == slave) { /* slave is the first slave */
                if (bond->slave_cnt > 1) { /* there are more slave */
                        bond->first_slave = slave->next;
                } else {
                        bond->first_slave = NULL; /* slave was the last one */
                }
        }

        slave->next = NULL;
        slave->prev = NULL;
        bond->slave_cnt--;
}

#ifdef CONFIG_NET_POLL_CONTROLLER
static inline int slave_enable_netpoll(struct slave *slave)
{
        struct netpoll *np;
        int err = 0;

        np = kzalloc(sizeof(*np), GFP_ATOMIC);
        err = -ENOMEM;
        if (!np)
                goto out;

        err = __netpoll_setup(np, slave->dev, GFP_ATOMIC);
        if (err) {
                kfree(np);
                goto out;
        }
        slave->np = np;
out:
        return err;
}
static inline void slave_disable_netpoll(struct slave *slave)
{
        struct netpoll *np = slave->np;

        if (!np)
                return;

        slave->np = NULL;
        __netpoll_free_rcu(np);
}
static inline bool slave_dev_support_netpoll(struct net_device *slave_dev)
{
        if (slave_dev->priv_flags & IFF_DISABLE_NETPOLL)
                return false;
        if (!slave_dev->netdev_ops->ndo_poll_controller)
                return false;
        return true;
}

static void bond_poll_controller(struct net_device *bond_dev)
{
}

static void __bond_netpoll_cleanup(struct bonding *bond)
{
        struct slave *slave;
        int i;

        bond_for_each_slave(bond, slave, i)
                if (IS_UP(slave->dev))
                        slave_disable_netpoll(slave);
}
static void bond_netpoll_cleanup(struct net_device *bond_dev)
{
        struct bonding *bond = netdev_priv(bond_dev);

        read_lock(&bond->lock);
        __bond_netpoll_cleanup(bond);
        read_unlock(&bond->lock);
}

static int bond_netpoll_setup(struct net_device *dev, struct netpoll_info *ni, gfp_t gfp)
{
        struct bonding *bond = netdev_priv(dev);
        struct slave *slave;
        int i, err = 0;

        read_lock(&bond->lock);
        bond_for_each_slave(bond, slave, i) {
                err = slave_enable_netpoll(slave);
                if (err) {
                        __bond_netpoll_cleanup(bond);
                        break;
                }
        }
        read_unlock(&bond->lock);
        return err;
}

static struct netpoll_info *bond_netpoll_info(struct bonding *bond)
{
        return bond->dev->npinfo;
}

#else
static inline int slave_enable_netpoll(struct slave *slave)
{
        return 0;
}
static inline void slave_disable_netpoll(struct slave *slave)
{
}
static void bond_netpoll_cleanup(struct net_device *bond_dev)
{
}
#endif

/*---------------------------------- IOCTL ----------------------------------*/

static int bond_sethwaddr(struct net_device *bond_dev,
                          struct net_device *slave_dev)
{
        pr_debug("bond_dev=%p\n", bond_dev);
        pr_debug("slave_dev=%p\n", slave_dev);
        pr_debug("slave_dev->addr_len=%d\n", slave_dev->addr_len);
        memcpy(bond_dev->dev_addr, slave_dev->dev_addr, slave_dev->addr_len);
        return 0;
}

static netdev_features_t bond_fix_features(struct net_device *dev,
        netdev_features_t features)
{
        struct slave *slave;
        struct bonding *bond = netdev_priv(dev);
        netdev_features_t mask;
        int i;

        read_lock(&bond->lock);

        if (!bond->first_slave) {
                /* Disable adding VLANs to empty bond. But why? --mq */
                features |= NETIF_F_VLAN_CHALLENGED;
                goto out;
        }

        mask = features;
        features &= ~NETIF_F_ONE_FOR_ALL;
        features |= NETIF_F_ALL_FOR_ALL;

        bond_for_each_slave(bond, slave, i) {
                features = netdev_increment_features(features,
                                                     slave->dev->features,
                                                     mask);
        }

out:
        read_unlock(&bond->lock);
        return features;
}

#define BOND_VLAN_FEATURES      (NETIF_F_ALL_CSUM | NETIF_F_SG | \
                                 NETIF_F_FRAGLIST | NETIF_F_ALL_TSO | \
                                 NETIF_F_HIGHDMA | NETIF_F_LRO)

static void bond_compute_features(struct bonding *bond)
{
        struct slave *slave;
        struct net_device *bond_dev = bond->dev;
        netdev_features_t vlan_features = BOND_VLAN_FEATURES;
        unsigned short max_hard_header_len = ETH_HLEN;
        unsigned int gso_max_size = GSO_MAX_SIZE;
        u16 gso_max_segs = GSO_MAX_SEGS;
        int i;
        unsigned int flags, dst_release_flag = IFF_XMIT_DST_RELEASE;

        read_lock(&bond->lock);

        if (!bond->first_slave)
                goto done;

        bond_for_each_slave(bond, slave, i) {
                vlan_features = netdev_increment_features(vlan_features,
                        slave->dev->vlan_features, BOND_VLAN_FEATURES);

                dst_release_flag &= slave->dev->priv_flags;
                if (slave->dev->hard_header_len > max_hard_header_len)
                        max_hard_header_len = slave->dev->hard_header_len;

                gso_max_size = min(gso_max_size, slave->dev->gso_max_size);
                gso_max_segs = min(gso_max_segs, slave->dev->gso_max_segs);
        }

done:
        bond_dev->vlan_features = vlan_features;
        bond_dev->hard_header_len = max_hard_header_len;
        bond_dev->gso_max_segs = gso_max_segs;
        netif_set_gso_max_size(bond_dev, gso_max_size);

        flags = bond_dev->priv_flags & ~IFF_XMIT_DST_RELEASE;
        bond_dev->priv_flags = flags | dst_release_flag;

        read_unlock(&bond->lock);

        netdev_change_features(bond_dev);
}

static void bond_setup_by_slave(struct net_device *bond_dev,
                                struct net_device *slave_dev)
{
        struct bonding *bond = netdev_priv(bond_dev);

        bond_dev->header_ops        = slave_dev->header_ops;

        bond_dev->type              = slave_dev->type;
        bond_dev->hard_header_len   = slave_dev->hard_header_len;
        bond_dev->addr_len          = slave_dev->addr_len;

        memcpy(bond_dev->broadcast, slave_dev->broadcast,
                slave_dev->addr_len);
        bond->setup_by_slave = 1;
}

/* On bonding slaves other than the currently active slave, suppress
 * duplicates except for alb non-mcast/bcast.
 */
static bool bond_should_deliver_exact_match(struct sk_buff *skb,
                                            struct slave *slave,
                                            struct bonding *bond)
{
        if (bond_is_slave_inactive(slave)) {
                if (bond->params.mode == BOND_MODE_ALB &&
                    skb->pkt_type != PACKET_BROADCAST &&
                    skb->pkt_type != PACKET_MULTICAST)
                        return false;
                return true;
        }
        return false;
}

static rx_handler_result_t bond_handle_frame(struct sk_buff **pskb)
{
        struct sk_buff *skb = *pskb;
        struct slave *slave;
        struct bonding *bond;
        int (*recv_probe)(const struct sk_buff *, struct bonding *,
                          struct slave *);
        int ret = RX_HANDLER_ANOTHER;

        skb = skb_share_check(skb, GFP_ATOMIC);
        if (unlikely(!skb))
                return RX_HANDLER_CONSUMED;

        *pskb = skb;

        slave = bond_slave_get_rcu(skb->dev);
        bond = slave->bond;

        if (bond->params.arp_interval)
                slave->dev->last_rx = jiffies;

        recv_probe = ACCESS_ONCE(bond->recv_probe);
        if (recv_probe) {
                ret = recv_probe(skb, bond, slave);
                if (ret == RX_HANDLER_CONSUMED) {
                        consume_skb(skb);
                        return ret;
                }
        }

        if (bond_should_deliver_exact_match(skb, slave, bond)) {
                return RX_HANDLER_EXACT;
        }

        skb->dev = bond->dev;

        if (bond->params.mode == BOND_MODE_ALB &&
            bond->dev->priv_flags & IFF_BRIDGE_PORT &&
            skb->pkt_type == PACKET_HOST) {

                if (unlikely(skb_cow_head(skb,
                                          skb->data - skb_mac_header(skb)))) {
                        kfree_skb(skb);
                        return RX_HANDLER_CONSUMED;
                }
                memcpy(eth_hdr(skb)->h_dest, bond->dev->dev_addr, ETH_ALEN);
        }

        return ret;
}

/* enslave device <slave> to bond device <master> */
int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
{
        struct bonding *bond = netdev_priv(bond_dev);
        const struct net_device_ops *slave_ops = slave_dev->netdev_ops;
        struct slave *new_slave = NULL;
        struct netdev_hw_addr *ha;
        struct sockaddr addr;
        int link_reporting;
        int res = 0;

        if (!bond->params.use_carrier &&
            slave_dev->ethtool_ops->get_link == NULL &&
            slave_ops->ndo_do_ioctl == NULL) {
                pr_warning("%s: Warning: no link monitoring support for %s\n",
                           bond_dev->name, slave_dev->name);
        }

        /* already enslaved */
        if (slave_dev->flags & IFF_SLAVE) {
                pr_debug("Error, Device was already enslaved\n");
                return -EBUSY;
        }

        /* vlan challenged mutual exclusion */
        /* no need to lock since we're protected by rtnl_lock */
        if (slave_dev->features & NETIF_F_VLAN_CHALLENGED) {
                pr_debug("%s: NETIF_F_VLAN_CHALLENGED\n", slave_dev->name);
                if (vlan_uses_dev(bond_dev)) {
                        pr_err("%s: Error: cannot enslave VLAN challenged slave %s on VLAN enabled bond %s\n",
                               bond_dev->name, slave_dev->name, bond_dev->name);
                        return -EPERM;
                } else {
                        pr_warning("%s: Warning: enslaved VLAN challenged slave %s. Adding VLANs will be blocked as long as %s is part of bond %s\n",
                                   bond_dev->name, slave_dev->name,
                                   slave_dev->name, bond_dev->name);
                }
        } else {
                pr_debug("%s: ! NETIF_F_VLAN_CHALLENGED\n", slave_dev->name);
        }

        /*
         * Old ifenslave binaries are no longer supported.  These can
         * be identified with moderate accuracy by the state of the slave:
         * the current ifenslave will set the interface down prior to
         * enslaving it; the old ifenslave will not.
         */
        if ((slave_dev->flags & IFF_UP)) {
                pr_err("%s is up. This may be due to an out of date ifenslave.\n",
                       slave_dev->name);
                res = -EPERM;
                goto err_undo_flags;
        }

        /* set bonding device ether type by slave - bonding netdevices are
         * created with ether_setup, so when the slave type is not ARPHRD_ETHER
         * there is a need to override some of the type dependent attribs/funcs.
         *
         * bond ether type mutual exclusion - don't allow slaves of dissimilar
         * ether type (eg ARPHRD_ETHER and ARPHRD_INFINIBAND) share the same bond
         */
        if (bond->slave_cnt == 0) {
                if (bond_dev->type != slave_dev->type) {
                        pr_debug("%s: change device type from %d to %d\n",
                                 bond_dev->name,
                                 bond_dev->type, slave_dev->type);

                        res = call_netdevice_notifiers(NETDEV_PRE_TYPE_CHANGE,
                                                       bond_dev);
                        res = notifier_to_errno(res);
                        if (res) {
                                pr_err("%s: refused to change device type\n",
                                       bond_dev->name);
                                res = -EBUSY;
                                goto err_undo_flags;
                        }

                        /* Flush unicast and multicast addresses */
                        dev_uc_flush(bond_dev);
                        dev_mc_flush(bond_dev);

                        if (slave_dev->type != ARPHRD_ETHER)
                                bond_setup_by_slave(bond_dev, slave_dev);
                        else {
                                ether_setup(bond_dev);
                                bond_dev->priv_flags &= ~IFF_TX_SKB_SHARING;
                        }

                        call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE,
                                                 bond_dev);
                }
        } else if (bond_dev->type != slave_dev->type) {
                pr_err("%s ether type (%d) is different from other slaves (%d), can not enslave it.\n",
                       slave_dev->name,
                       slave_dev->type, bond_dev->type);
                res = -EINVAL;
                goto err_undo_flags;
        }

        if (slave_ops->ndo_set_mac_address == NULL) {
                if (bond->slave_cnt == 0) {
                        pr_warning("%s: Warning: The first slave device specified does not support setting the MAC address. Setting fail_over_mac to active.",
                                   bond_dev->name);
                        bond->params.fail_over_mac = BOND_FOM_ACTIVE;
                } else if (bond->params.fail_over_mac != BOND_FOM_ACTIVE) {
                        pr_err("%s: Error: The slave device specified does not support setting the MAC address, but fail_over_mac is not set to active.\n",
                               bond_dev->name);
                        res = -EOPNOTSUPP;
                        goto err_undo_flags;
                }
        }

        call_netdevice_notifiers(NETDEV_JOIN, slave_dev);

        /* If this is the first slave, then we need to set the master's hardware
         * address to be the same as the slave's. */
        if (is_zero_ether_addr(bond->dev->dev_addr))
                memcpy(bond->dev->dev_addr, slave_dev->dev_addr,
                       slave_dev->addr_len);


        new_slave = kzalloc(sizeof(struct slave), GFP_KERNEL);
        if (!new_slave) {
                res = -ENOMEM;
                goto err_undo_flags;
        }

        /*
         * Set the new_slave's queue_id to be zero.  Queue ID mapping
         * is set via sysfs or module option if desired.
         */
        new_slave->queue_id = 0;

        /* Save slave's original mtu and then set it to match the bond */
        new_slave->original_mtu = slave_dev->mtu;
        res = dev_set_mtu(slave_dev, bond->dev->mtu);
        if (res) {
                pr_debug("Error %d calling dev_set_mtu\n", res);
                goto err_free;
        }

        /*
         * Save slave's original ("permanent") mac address for modes
         * that need it, and for restoring it upon release, and then
         * set it to the master's address
         */
        memcpy(new_slave->perm_hwaddr, slave_dev->dev_addr, ETH_ALEN);

        if (!bond->params.fail_over_mac) {
                /*
                 * Set slave to master's mac address.  The application already
                 * set the master's mac address to that of the first slave
                 */
                memcpy(addr.sa_data, bond_dev->dev_addr, bond_dev->addr_len);
                addr.sa_family = slave_dev->type;
                res = dev_set_mac_address(slave_dev, &addr);
                if (res) {
                        pr_debug("Error %d calling set_mac_address\n", res);
                        goto err_restore_mtu;
                }
        }

        res = netdev_set_bond_master(slave_dev, bond_dev);
        if (res) {
                pr_debug("Error %d calling netdev_set_bond_master\n", res);
                goto err_restore_mac;
        }

        /* open the slave since the application closed it */
        res = dev_open(slave_dev);
        if (res) {
                pr_debug("Opening slave %s failed\n", slave_dev->name);
                goto err_unset_master;
        }

        new_slave->bond = bond;
        new_slave->dev = slave_dev;
        slave_dev->priv_flags |= IFF_BONDING;

        if (bond_is_lb(bond)) {
                /* bond_alb_init_slave() must be called before all other stages since
                 * it might fail and we do not want to have to undo everything
                 */
                res = bond_alb_init_slave(bond, new_slave);
                if (res)
                        goto err_close;
        }

        /* If the mode USES_PRIMARY, then the new slave gets the
         * master's promisc (and mc) settings only if it becomes the
         * curr_active_slave, and that is taken care of later when calling
         * bond_change_active()
         */
        if (!USES_PRIMARY(bond->params.mode)) {
                /* set promiscuity level to new slave */
                if (bond_dev->flags & IFF_PROMISC) {
                        res = dev_set_promiscuity(slave_dev, 1);
                        if (res)
                                goto err_close;
                }

                /* set allmulti level to new slave */
                if (bond_dev->flags & IFF_ALLMULTI) {
                        res = dev_set_allmulti(slave_dev, 1);
                        if (res)
                                goto err_close;
                }

                netif_addr_lock_bh(bond_dev);
                /* upload master's mc_list to new slave */
                netdev_for_each_mc_addr(ha, bond_dev)
                        dev_mc_add(slave_dev, ha->addr);
                netif_addr_unlock_bh(bond_dev);
        }

        if (bond->params.mode == BOND_MODE_8023AD) {
                /* add lacpdu mc addr to mc list */
                u8 lacpdu_multicast[ETH_ALEN] = MULTICAST_LACPDU_ADDR;

                dev_mc_add(slave_dev, lacpdu_multicast);
        }

        bond_add_vlans_on_slave(bond, slave_dev);

        write_lock_bh(&bond->lock);

        bond_attach_slave(bond, new_slave);

        new_slave->delay = 0;
        new_slave->link_failure_count = 0;

        write_unlock_bh(&bond->lock);

        bond_compute_features(bond);

        read_lock(&bond->lock);

        new_slave->last_arp_rx = jiffies -
                (msecs_to_jiffies(bond->params.arp_interval) + 1);

        if (bond->params.miimon && !bond->params.use_carrier) {
                link_reporting = bond_check_dev_link(bond, slave_dev, 1);

                if ((link_reporting == -1) && !bond->params.arp_interval) {
                        /*
                         * miimon is set but a bonded network driver
                         * does not support ETHTOOL/MII and
                         * arp_interval is not set.  Note: if
                         * use_carrier is enabled, we will never go
                         * here (because netif_carrier is always
                         * supported); thus, we don't need to change
                         * the messages for netif_carrier.
                         */
                        pr_warning("%s: Warning: MII and ETHTOOL support not available for interface %s, and arp_interval/arp_ip_target module parameters not specified, thus bonding will not detect link failures! see bonding.txt for details.\n",
                               bond_dev->name, slave_dev->name);
                } else if (link_reporting == -1) {
                        /* unable get link status using mii/ethtool */
                        pr_warning("%s: Warning: can't get link status from interface %s; the network driver associated with this interface does not support MII or ETHTOOL link status reporting, thus miimon has no effect on this interface.\n",
                                   bond_dev->name, slave_dev->name);
                }
        }

        /* check for initial state */
        if (bond->params.miimon) {
                if (bond_check_dev_link(bond, slave_dev, 0) == BMSR_LSTATUS) {
                        if (bond->params.updelay) {
                                new_slave->link = BOND_LINK_BACK;
                                new_slave->delay = bond->params.updelay;
                        } else {
                                new_slave->link = BOND_LINK_UP;
                        }
                } else {
                        new_slave->link = BOND_LINK_DOWN;
                }
        } else if (bond->params.arp_interval) {
                new_slave->link = (netif_carrier_ok(slave_dev) ?
                        BOND_LINK_UP : BOND_LINK_DOWN);
        } else {
                new_slave->link = BOND_LINK_UP;
        }

        if (new_slave->link != BOND_LINK_DOWN)
                new_slave->jiffies = jiffies;
        pr_debug("Initial state of slave_dev is BOND_LINK_%s\n",
                new_slave->link == BOND_LINK_DOWN ? "DOWN" :
                        (new_slave->link == BOND_LINK_UP ? "UP" : "BACK"));

        bond_update_speed_duplex(new_slave);

        if (USES_PRIMARY(bond->params.mode) && bond->params.primary[0]) {
                /* if there is a primary slave, remember it */
                if (strcmp(bond->params.primary, new_slave->dev->name) == 0) {
                        bond->primary_slave = new_slave;
                        bond->force_primary = true;
                }
        }

        write_lock_bh(&bond->curr_slave_lock);

        switch (bond->params.mode) {
        case BOND_MODE_ACTIVEBACKUP:
                bond_set_slave_inactive_flags(new_slave);
                bond_select_active_slave(bond);
                break;
        case BOND_MODE_8023AD:
                /* in 802.3ad mode, the internal mechanism
                 * will activate the slaves in the selected
                 * aggregator
                 */
                bond_set_slave_inactive_flags(new_slave);
                /* if this is the first slave */
                if (bond->slave_cnt == 1) {
                        SLAVE_AD_INFO(new_slave).id = 1;
                        /* Initialize AD with the number of times that the AD timer is called in 1 second
                         * can be called only after the mac address of the bond is set
                         */
                        bond_3ad_initialize(bond, 1000/AD_TIMER_INTERVAL);
                } else {
                        SLAVE_AD_INFO(new_slave).id =
                                SLAVE_AD_INFO(new_slave->prev).id + 1;
                }

                bond_3ad_bind_slave(new_slave);
                break;
        case BOND_MODE_TLB:
        case BOND_MODE_ALB:
                bond_set_active_slave(new_slave);
                bond_set_slave_inactive_flags(new_slave);
                bond_select_active_slave(bond);
                break;
        default:
                pr_debug("This slave is always active in trunk mode\n");

                /* always active in trunk mode */
                bond_set_active_slave(new_slave);

                /* In trunking mode there is little meaning to curr_active_slave
                 * anyway (it holds no special properties of the bond device),
                 * so we can change it without calling change_active_interface()
                 */
                if (!bond->curr_active_slave && new_slave->link == BOND_LINK_UP)
                        bond->curr_active_slave = new_slave;

                break;
        } /* switch(bond_mode) */

        write_unlock_bh(&bond->curr_slave_lock);

        bond_set_carrier(bond);

#ifdef CONFIG_NET_POLL_CONTROLLER
        slave_dev->npinfo = bond_netpoll_info(bond);
        if (slave_dev->npinfo) {
                if (slave_enable_netpoll(new_slave)) {
                        read_unlock(&bond->lock);
                        pr_info("Error, %s: master_dev is using netpoll, "
                                 "but new slave device does not support netpoll.\n",
                                 bond_dev->name);
                        res = -EBUSY;
                        goto err_detach;
                }
        }
#endif

        read_unlock(&bond->lock);

        res = bond_create_slave_symlinks(bond_dev, slave_dev);
        if (res)
                goto err_detach;

        res = netdev_rx_handler_register(slave_dev, bond_handle_frame,
                                         new_slave);
        if (res) {
                pr_debug("Error %d calling netdev_rx_handler_register\n", res);
                goto err_dest_symlinks;
        }

        pr_info("%s: enslaving %s as a%s interface with a%s link.\n",
                bond_dev->name, slave_dev->name,
                bond_is_active_slave(new_slave) ? "n active" : " backup",
                new_slave->link != BOND_LINK_DOWN ? "n up" : " down");

        /* enslave is successful */
        return 0;

/* Undo stages on error */
err_dest_symlinks:
        bond_destroy_slave_symlinks(bond_dev, slave_dev);

err_detach:
        write_lock_bh(&bond->lock);
        bond_detach_slave(bond, new_slave);
        write_unlock_bh(&bond->lock);

err_close:
        dev_close(slave_dev);

err_unset_master:
        netdev_set_bond_master(slave_dev, NULL);

err_restore_mac:
        if (!bond->params.fail_over_mac) {
                /* XXX TODO - fom follow mode needs to change master's
                 * MAC if this slave's MAC is in use by the bond, or at
                 * least print a warning.
                 */
                memcpy(addr.sa_data, new_slave->perm_hwaddr, ETH_ALEN);
                addr.sa_family = slave_dev->type;
                dev_set_mac_address(slave_dev, &addr);
        }

err_restore_mtu:
        dev_set_mtu(slave_dev, new_slave->original_mtu);

err_free:
        kfree(new_slave);

err_undo_flags:
        bond_compute_features(bond);

        return res;
}

/*
 * Try to release the slave device <slave> from the bond device <master>
 * It is legal to access curr_active_slave without a lock because all the function
 * is write-locked.
 *
 * The rules for slave state should be:
 *   for Active/Backup:
 *     Active stays on all backups go down
 *   for Bonded connections:
 *     The first up interface should be left on and all others downed.
 */
int bond_release(struct net_device *bond_dev, struct net_device *slave_dev)
{
        struct bonding *bond = netdev_priv(bond_dev);
        struct slave *slave, *oldcurrent;
        struct sockaddr addr;
        netdev_features_t old_features = bond_dev->features;

        /* slave is not a slave or master is not master of this slave */
        if (!(slave_dev->flags & IFF_SLAVE) ||
            (slave_dev->master != bond_dev)) {
                pr_err("%s: Error: cannot release %s.\n",
                       bond_dev->name, slave_dev->name);
                return -EINVAL;
        }

        block_netpoll_tx();
        call_netdevice_notifiers(NETDEV_RELEASE, bond_dev);
        write_lock_bh(&bond->lock);

        slave = bond_get_slave_by_dev(bond, slave_dev);
        if (!slave) {
                /* not a slave of this bond */
                pr_info("%s: %s not enslaved\n",
                        bond_dev->name, slave_dev->name);
                write_unlock_bh(&bond->lock);
                unblock_netpoll_tx();
                return -EINVAL;
        }

        /* unregister rx_handler early so bond_handle_frame wouldn't be called
         * for this slave anymore.
         */
        netdev_rx_handler_unregister(slave_dev);
        write_unlock_bh(&bond->lock);
        synchronize_net();
        write_lock_bh(&bond->lock);

        if (!bond->params.fail_over_mac) {
                if (ether_addr_equal(bond_dev->dev_addr, slave->perm_hwaddr) &&
                    bond->slave_cnt > 1)
                        pr_warning("%s: Warning: the permanent HWaddr of %s - %pM - is still in use by %s. Set the HWaddr of %s to a different address to avoid conflicts.\n",
                                   bond_dev->name, slave_dev->name,
                                   slave->perm_hwaddr,
                                   bond_dev->name, slave_dev->name);
        }

        /* Inform AD package of unbinding of slave. */
        if (bond->params.mode == BOND_MODE_8023AD) {
                /* must be called before the slave is
                 * detached from the list
                 */
                bond_3ad_unbind_slave(slave);
        }

        pr_info("%s: releasing %s interface %s\n",
                bond_dev->name,
                bond_is_active_slave(slave) ? "active" : "backup",
                slave_dev->name);

        oldcurrent = bond->curr_active_slave;

        bond->current_arp_slave = NULL;

        /* release the slave from its bond */
        bond_detach_slave(bond, slave);

        if (bond->primary_slave == slave)
                bond->primary_slave = NULL;

        if (oldcurrent == slave)
                bond_change_active_slave(bond, NULL);

        if (bond_is_lb(bond)) {
                /* Must be called only after the slave has been
                 * detached from the list and the curr_active_slave
                 * has been cleared (if our_slave == old_current),
                 * but before a new active slave is selected.
                 */
                write_unlock_bh(&bond->lock);
                bond_alb_deinit_slave(bond, slave);
                write_lock_bh(&bond->lock);
        }

        if (oldcurrent == slave) {
                /*
                 * Note that we hold RTNL over this sequence, so there
                 * is no concern that another slave add/remove event
                 * will interfere.
                 */
                write_unlock_bh(&bond->lock);
                read_lock(&bond->lock);
                write_lock_bh(&bond->curr_slave_lock);

                bond_select_active_slave(bond);

                write_unlock_bh(&bond->curr_slave_lock);
                read_unlock(&bond->lock);
                write_lock_bh(&bond->lock);
        }

        if (bond->slave_cnt == 0) {
                bond_set_carrier(bond);

                /* if the last slave was removed, zero the mac address
                 * of the master so it will be set by the application
                 * to the mac address of the first slave
                 */
                memset(bond_dev->dev_addr, 0, bond_dev->addr_len);

                if (bond_vlan_used(bond)) {
                        pr_warning("%s: Warning: clearing HW address of %s while it still has VLANs.\n",
                                   bond_dev->name, bond_dev->name);
                        pr_warning("%s: When re-adding slaves, make sure the bond's HW address matches its VLANs'.\n",
                                   bond_dev->name);
                }
        }

        write_unlock_bh(&bond->lock);
        unblock_netpoll_tx();

        if (bond->slave_cnt == 0)
                call_netdevice_notifiers(NETDEV_CHANGEADDR, bond->dev);

        bond_compute_features(bond);
        if (!(bond_dev->features & NETIF_F_VLAN_CHALLENGED) &&
            (old_features & NETIF_F_VLAN_CHALLENGED))
                pr_info("%s: last VLAN challenged slave %s left bond %s. VLAN blocking is removed\n",
                        bond_dev->name, slave_dev->name, bond_dev->name);

        /* must do this from outside any spinlocks */
        bond_destroy_slave_symlinks(bond_dev, slave_dev);

        bond_del_vlans_from_slave(bond, slave_dev);

        /* If the mode USES_PRIMARY, then we should only remove its
         * promisc and mc settings if it was the curr_active_slave, but that was
         * already taken care of above when we detached the slave
         */
        if (!USES_PRIMARY(bond->params.mode)) {
                /* unset promiscuity level from slave */
                if (bond_dev->flags & IFF_PROMISC)
                        dev_set_promiscuity(slave_dev, -1);

                /* unset allmulti level from slave */
                if (bond_dev->flags & IFF_ALLMULTI)
                        dev_set_allmulti(slave_dev, -1);

                /* flush master's mc_list from slave */
                netif_addr_lock_bh(bond_dev);
                bond_mc_list_flush(bond_dev, slave_dev);
                netif_addr_unlock_bh(bond_dev);
        }

        netdev_set_bond_master(slave_dev, NULL);

        slave_disable_netpoll(slave);

        /* close slave before restoring its mac address */
        dev_close(slave_dev);

        if (bond->params.fail_over_mac != BOND_FOM_ACTIVE) {
                /* restore original ("permanent") mac address */
                memcpy(addr.sa_data, slave->perm_hwaddr, ETH_ALEN);
                addr.sa_family = slave_dev->type;
                dev_set_mac_address(slave_dev, &addr);
        }

        dev_set_mtu(slave_dev, slave->original_mtu);

        slave_dev->priv_flags &= ~IFF_BONDING;

        kfree(slave);

        return 0;  /* deletion OK */
}

/*
* First release a slave and then destroy the bond if no more slaves are left.
* Must be under rtnl_lock when this function is called.
*/
static int  bond_release_and_destroy(struct net_device *bond_dev,
                                     struct net_device *slave_dev)
{
        struct bonding *bond = netdev_priv(bond_dev);
        int ret;

        ret = bond_release(bond_dev, slave_dev);
        if ((ret == 0) && (bond->slave_cnt == 0)) {
                bond_dev->priv_flags |= IFF_DISABLE_NETPOLL;
                pr_info("%s: destroying bond %s.\n",
                        bond_dev->name, bond_dev->name);
                unregister_netdevice(bond_dev);
        }
        return ret;
}

/*
 * This function releases all slaves.
 */
static int bond_release_all(struct net_device *bond_dev)
{
        struct bonding *bond = netdev_priv(bond_dev);
        struct slave *slave;
        struct net_device *slave_dev;
        struct sockaddr addr;

        write_lock_bh(&bond->lock);

        netif_carrier_off(bond_dev);

        if (bond->slave_cnt == 0)
                goto out;

        bond->current_arp_slave = NULL;
        bond->primary_slave = NULL;
        bond_change_active_slave(bond, NULL);

        while ((slave = bond->first_slave) != NULL) {
                /* Inform AD package of unbinding of slave
                 * before slave is detached from the list.
                 */
                if (bond->params.mode == BOND_MODE_8023AD)
                        bond_3ad_unbind_slave(slave);

                slave_dev = slave->dev;
                bond_detach_slave(bond, slave);

                /* now that the slave is detached, unlock and perform
                 * all the undo steps that should not be called from
                 * within a lock.
                 */
                write_unlock_bh(&bond->lock);

                /* unregister rx_handler early so bond_handle_frame wouldn't
                 * be called for this slave anymore.
                 */
                netdev_rx_handler_unregister(slave_dev);
                synchronize_net();

                if (bond_is_lb(bond)) {
                        /* must be called only after the slave
                         * has been detached from the list
                         */
                        bond_alb_deinit_slave(bond, slave);
                }

                bond_destroy_slave_symlinks(bond_dev, slave_dev);
                bond_del_vlans_from_slave(bond, slave_dev);

                /* If the mode USES_PRIMARY, then we should only remove its
                 * promisc and mc settings if it was the curr_active_slave, but that was
                 * already taken care of above when we detached the slave
                 */
                if (!USES_PRIMARY(bond->params.mode)) {
                        /* unset promiscuity level from slave */
                        if (bond_dev->flags & IFF_PROMISC)
                                dev_set_promiscuity(slave_dev, -1);

                        /* unset allmulti level from slave */
                        if (bond_dev->flags & IFF_ALLMULTI)
                                dev_set_allmulti(slave_dev, -1);

                        /* flush master's mc_list from slave */
                        netif_addr_lock_bh(bond_dev);
                        bond_mc_list_flush(bond_dev, slave_dev);
                        netif_addr_unlock_bh(bond_dev);
                }

                netdev_set_bond_master(slave_dev, NULL);

                slave_disable_netpoll(slave);

                /* close slave before restoring its mac address */
                dev_close(slave_dev);

                if (!bond->params.fail_over_mac) {
                        /* restore original ("permanent") mac address*/
                        memcpy(addr.sa_data, slave->perm_hwaddr, ETH_ALEN);
                        addr.sa_family = slave_dev->type;
                        dev_set_mac_address(slave_dev, &addr);
                }

                kfree(slave);

                /* re-acquire the lock before getting the next slave */
                write_lock_bh(&bond->lock);
        }

        /* zero the mac address of the master so it will be
         * set by the application to the mac address of the
         * first slave
         */
        memset(bond_dev->dev_addr, 0, bond_dev->addr_len);

        if (bond_vlan_used(bond)) {
                pr_warning("%s: Warning: clearing HW address of %s while it still has VLANs.\n",
                           bond_dev->name, bond_dev->name);
                pr_warning("%s: When re-adding slaves, make sure the bond's HW address matches its VLANs'.\n",
                           bond_dev->name);
        }

        pr_info("%s: released all slaves\n", bond_dev->name);

out:
        write_unlock_bh(&bond->lock);

        bond_compute_features(bond);

        return 0;
}

/*
 * This function changes the active slave to slave <slave_dev>.
 * It returns -EINVAL in the following cases.
 *  - <slave_dev> is not found in the list.
 *  - There is not active slave now.
 *  - <slave_dev> is already active.
 *  - The link state of <slave_dev> is not BOND_LINK_UP.
 *  - <slave_dev> is not running.
 * In these cases, this function does nothing.
 * In the other cases, current_slave pointer is changed and 0 is returned.
 */
static int bond_ioctl_change_active(struct net_device *bond_dev, struct net_device *slave_dev)
{
        struct bonding *bond = netdev_priv(bond_dev);
        struct slave *old_active = NULL;
        struct slave *new_active = NULL;
        int res = 0;

        if (!USES_PRIMARY(bond->params.mode))
                return -EINVAL;

        /* Verify that master_dev is indeed the master of slave_dev */
        if (!(slave_dev->flags & IFF_SLAVE) || (slave_dev->master != bond_dev))
                return -EINVAL;

        read_lock(&bond->lock);

        read_lock(&bond->curr_slave_lock);
        old_active = bond->curr_active_slave;
        read_unlock(&bond->curr_slave_lock);

        new_active = bond_get_slave_by_dev(bond, slave_dev);

        /*
         * Changing to the current active: do nothing; return success.
         */
        if (new_active && (new_active == old_active)) {
                read_unlock(&bond->lock);
                return 0;
        }

        if ((new_active) &&
            (old_active) &&
            (new_active->link == BOND_LINK_UP) &&
            IS_UP(new_active->dev)) {
                block_netpoll_tx();
                write_lock_bh(&bond->curr_slave_lock);
                bond_change_active_slave(bond, new_active);
                write_unlock_bh(&bond->curr_slave_lock);
                unblock_netpoll_tx();
        } else
                res = -EINVAL;

        read_unlock(&bond->lock);

        return res;
}

static int bond_info_query(struct net_device *bond_dev, struct ifbond *info)
{
        struct bonding *bond = netdev_priv(bond_dev);

        info->bond_mode = bond->params.mode;
        info->miimon = bond->params.miimon;

        read_lock(&bond->lock);
        info->num_slaves = bond->slave_cnt;
        read_unlock(&bond->lock);

        return 0;
}

static int bond_slave_info_query(struct net_device *bond_dev, struct ifslave *info)
{
        struct bonding *bond = netdev_priv(bond_dev);
        struct slave *slave;
        int i, res = -ENODEV;

        read_lock(&bond->lock);

        bond_for_each_slave(bond, slave, i) {
                if (i == (int)info->slave_id) {
                        res = 0;
                        strcpy(info->slave_name, slave->dev->name);
                        info->link = slave->link;
                        info->state = bond_slave_state(slave);
                        info->link_failure_count = slave->link_failure_count;
                        break;
                }
        }

        read_unlock(&bond->lock);

        return res;
}

/*-------------------------------- Monitoring -------------------------------*/


static int bond_miimon_inspect(struct bonding *bond)
{
        struct slave *slave;
        int i, link_state, commit = 0;
        bool ignore_updelay;

        ignore_updelay = !bond->curr_active_slave ? true : false;

        bond_for_each_slave(bond, slave, i) {
                slave->new_link = BOND_LINK_NOCHANGE;

                link_state = bond_check_dev_link(bond, slave->dev, 0);

                switch (slave->link) {
                case BOND_LINK_UP:
                        if (link_state)
                                continue;

                        slave->link = BOND_LINK_FAIL;
                        slave->delay = bond->params.downdelay;
                        if (slave->delay) {
                                pr_info("%s: link status down for %sinterface %s, disabling it in %d ms.\n",
                                        bond->dev->name,
                                        (bond->params.mode ==
                                         BOND_MODE_ACTIVEBACKUP) ?
                                        (bond_is_active_slave(slave) ?
                                         "active " : "backup ") : "",
                                        slave->dev->name,
                                        bond->params.downdelay * bond->params.miimon);
                        }
                        /*FALLTHRU*/
                case BOND_LINK_FAIL:
                        if (link_state) {
                                /*
                                 * recovered before downdelay expired
                                 */
                                slave->link = BOND_LINK_UP;
                                slave->jiffies = jiffies;
                                pr_info("%s: link status up again after %d ms for interface %s.\n",
                                        bond->dev->name,
                                        (bond->params.downdelay - slave->delay) *
                                        bond->params.miimon,
                                        slave->dev->name);
                                continue;
                        }

                        if (slave->delay <= 0) {
                                slave->new_link = BOND_LINK_DOWN;
                                commit++;
                                continue;
                        }

                        slave->delay--;
                        break;

                case BOND_LINK_DOWN:
                        if (!link_state)
                                continue;

                        slave->link = BOND_LINK_BACK;
                        slave->delay = bond->params.updelay;

                        if (slave->delay) {
                                pr_info("%s: link status up for interface %s, enabling it in %d ms.\n",
                                        bond->dev->name, slave->dev->name,
                                        ignore_updelay ? 0 :
                                        bond->params.updelay *
                                        bond->params.miimon);
                        }
                        /*FALLTHRU*/
                case BOND_LINK_BACK:
                        if (!link_state) {
                                slave->link = BOND_LINK_DOWN;
                                pr_info("%s: link status down again after %d ms for interface %s.\n",
                                        bond->dev->name,
                                        (bond->params.updelay - slave->delay) *
                                        bond->params.miimon,
                                        slave->dev->name);

                                continue;
                        }

                        if (ignore_updelay)
                                slave->delay = 0;

                        if (slave->delay <= 0) {
                                slave->new_link = BOND_LINK_UP;
                                commit++;
                                ignore_updelay = false;
                                continue;
                        }

                        slave->delay--;
                        break;
                }
        }

        return commit;
}

static void bond_miimon_commit(struct bonding *bond)
{
        struct slave *slave;
        int i;

        bond_for_each_slave(bond, slave, i) {
                switch (slave->new_link) {
                case BOND_LINK_NOCHANGE:
                        continue;

                case BOND_LINK_UP:
                        slave->link = BOND_LINK_UP;
                        slave->jiffies = jiffies;

                        if (bond->params.mode == BOND_MODE_8023AD) {
                                /* prevent it from being the active one */
                                bond_set_backup_slave(slave);
                        } else if (bond->params.mode != BOND_MODE_ACTIVEBACKUP) {
                                /* make it immediately active */
                                bond_set_active_slave(slave);
                        } else if (slave != bond->primary_slave) {
                                /* prevent it from being the active one */
                                bond_set_backup_slave(slave);
                        }

                        bond_update_speed_duplex(slave);

                        pr_info("%s: link status definitely up for interface %s, %u Mbps %s duplex.\n",
                                bond->dev->name, slave->dev->name,
                                slave->speed, slave->duplex ? "full" : "half");

                        /* notify ad that the link status has changed */
                        if (bond->params.mode == BOND_MODE_8023AD)
                                bond_3ad_handle_link_change(slave, BOND_LINK_UP);

                        if (bond_is_lb(bond))
                                bond_alb_handle_link_change(bond, slave,
                                                            BOND_LINK_UP);

                        if (!bond->curr_active_slave ||
                            (slave == bond->primary_slave))
                                goto do_failover;

                        continue;

                case BOND_LINK_DOWN:
                        if (slave->link_failure_count < UINT_MAX)
                                slave->link_failure_count++;

                        slave->link = BOND_LINK_DOWN;

                        if (bond->params.mode == BOND_MODE_ACTIVEBACKUP ||
                            bond->params.mode == BOND_MODE_8023AD)
                                bond_set_slave_inactive_flags(slave);

                        pr_info("%s: link status definitely down for interface %s, disabling it\n",
                                bond->dev->name, slave->dev->name);

                        if (bond->params.mode == BOND_MODE_8023AD)
                                bond_3ad_handle_link_change(slave,
                                                            BOND_LINK_DOWN);

                        if (bond_is_lb(bond))
                                bond_alb_handle_link_change(bond, slave,
                                                            BOND_LINK_DOWN);

                        if (slave == bond->curr_active_slave)
                                goto do_failover;

                        continue;

                default:
                        pr_err("%s: invalid new link %d on slave %s\n",
                               bond->dev->name, slave->new_link,
                               slave->dev->name);
                        slave->new_link = BOND_LINK_NOCHANGE;

                        continue;
                }

do_failover:
                ASSERT_RTNL();
                block_netpoll_tx();
                write_lock_bh(&bond->curr_slave_lock);
                bond_select_active_slave(bond);
                write_unlock_bh(&bond->curr_slave_lock);
                unblock_netpoll_tx();
        }

        bond_set_carrier(bond);
}

/*
 * bond_mii_monitor
 *
 * Really a wrapper that splits the mii monitor into two phases: an
 * inspection, then (if inspection indicates something needs to be done)
 * an acquisition of appropriate locks followed by a commit phase to
 * implement whatever link state changes are indicated.
 */
void bond_mii_monitor(struct work_struct *work)
{
        struct bonding *bond = container_of(work, struct bonding,
                                            mii_work.work);
        bool should_notify_peers = false;
        unsigned long delay;

        read_lock(&bond->lock);

        delay = msecs_to_jiffies(bond->params.miimon);

        if (bond->slave_cnt == 0)
                goto re_arm;

        should_notify_peers = bond_should_notify_peers(bond);

        if (bond_miimon_inspect(bond)) {
                read_unlock(&bond->lock);

                /* Race avoidance with bond_close cancel of workqueue */
                if (!rtnl_trylock()) {
                        read_lock(&bond->lock);
                        delay = 1;
                        should_notify_peers = false;
                        goto re_arm;
                }

                read_lock(&bond->lock);

                bond_miimon_commit(bond);

                read_unlock(&bond->lock);
                rtnl_unlock();  /* might sleep, hold no other locks */
                read_lock(&bond->lock);
        }

re_arm:
        if (bond->params.miimon)
                queue_delayed_work(bond->wq, &bond->mii_work, delay);

        read_unlock(&bond->lock);

        if (should_notify_peers) {
                if (!rtnl_trylock()) {
                        read_lock(&bond->lock);
                        bond->send_peer_notif++;
                        read_unlock(&bond->lock);
                        return;
                }
                call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, bond->dev);
                rtnl_unlock();
        }
}

static int bond_has_this_ip(struct bonding *bond, __be32 ip)
{
        struct vlan_entry *vlan;
        struct net_device *vlan_dev;

        if (ip == bond_confirm_addr(bond->dev, 0, ip))
                return 1;

        list_for_each_entry(vlan, &bond->vlan_list, vlan_list) {
                rcu_read_lock();
                vlan_dev = __vlan_find_dev_deep(bond->dev, vlan->vlan_id);
                rcu_read_unlock();
                if (vlan_dev && ip == bond_confirm_addr(vlan_dev, 0, ip))
                        return 1;
        }

        return 0;
}

/*
 * We go to the (large) trouble of VLAN tagging ARP frames because
 * switches in VLAN mode (especially if ports are configured as
 * "native" to a VLAN) might not pass non-tagged frames.
 */
static void bond_arp_send(struct net_device *slave_dev, int arp_op, __be32 dest_ip, __be32 src_ip, unsigned short vlan_id)
{
        struct sk_buff *skb;

        pr_debug("arp %d on slave %s: dst %x src %x vid %d\n", arp_op,
                 slave_dev->name, dest_ip, src_ip, vlan_id);

        skb = arp_create(arp_op, ETH_P_ARP, dest_ip, slave_dev, src_ip,
                         NULL, slave_dev->dev_addr, NULL);

        if (!skb) {
                pr_err("ARP packet allocation failed\n");
                return;
        }
        if (vlan_id) {
                skb = vlan_put_tag(skb, vlan_id);
                if (!skb) {
                        pr_err("failed to insert VLAN tag\n");
                        return;
                }
        }
        arp_xmit(skb);
}


static void bond_arp_send_all(struct bonding *bond, struct slave *slave)
{
        int i, vlan_id;
        __be32 *targets = bond->params.arp_targets;
        struct vlan_entry *vlan;
        struct net_device *vlan_dev = NULL;
        struct rtable *rt;

        for (i = 0; (i < BOND_MAX_ARP_TARGETS); i++) {
                __be32 addr;
                if (!targets[i])
                        break;
                pr_debug("basa: target %x\n", targets[i]);
                if (!bond_vlan_used(bond)) {
                        pr_debug("basa: empty vlan: arp_send\n");
                        addr = bond_confirm_addr(bond->dev, targets[i], 0);
                        bond_arp_send(slave->dev, ARPOP_REQUEST, targets[i],
                                      addr, 0);
                        continue;
                }

                /*
                 * If VLANs are configured, we do a route lookup to
                 * determine which VLAN interface would be used, so we
                 * can tag the ARP with the proper VLAN tag.
                 */
                rt = ip_route_output(dev_net(bond->dev), targets[i], 0,
                                     RTO_ONLINK, 0);
                if (IS_ERR(rt)) {
                        if (net_ratelimit()) {
                                pr_warning("%s: no route to arp_ip_target %pI4\n",
                                           bond->dev->name, &targets[i]);
                        }
                        continue;
                }

                /*
                 * This target is not on a VLAN
                 */
                if (rt->dst.dev == bond->dev) {
                        ip_rt_put(rt);
                        pr_debug("basa: rtdev == bond->dev: arp_send\n");
                        addr = bond_confirm_addr(bond->dev, targets[i], 0);
                        bond_arp_send(slave->dev, ARPOP_REQUEST, targets[i],
                                      addr, 0);
                        continue;
                }

                vlan_id = 0;
                list_for_each_entry(vlan, &bond->vlan_list, vlan_list) {
                        rcu_read_lock();
                        vlan_dev = __vlan_find_dev_deep(bond->dev,
                                                        vlan->vlan_id);
                        rcu_read_unlock();
                        if (vlan_dev == rt->dst.dev) {
                                vlan_id = vlan->vlan_id;
                                pr_debug("basa: vlan match on %s %d\n",
                                       vlan_dev->name, vlan_id);
                                break;
                        }
                }

                if (vlan_id && vlan_dev) {
                        ip_rt_put(rt);
                        addr = bond_confirm_addr(vlan_dev, targets[i], 0);
                        bond_arp_send(slave->dev, ARPOP_REQUEST, targets[i],
                                      addr, vlan_id);
                        continue;
                }

                if (net_ratelimit()) {
                        pr_warning("%s: no path to arp_ip_target %pI4 via rt.dev %s\n",
                                   bond->dev->name, &targets[i],
                                   rt->dst.dev ? rt->dst.dev->name : "NULL");
                }
                ip_rt_put(rt);
        }
}

static void bond_validate_arp(struct bonding *bond, struct slave *slave, __be32 sip, __be32 tip)
{
        int i;
        __be32 *targets = bond->params.arp_targets;

        for (i = 0; (i < BOND_MAX_ARP_TARGETS) && targets[i]; i++) {
                pr_debug("bva: sip %pI4 tip %pI4 t[%d] %pI4 bhti(tip) %d\n",
                         &sip, &tip, i, &targets[i],
                         bond_has_this_ip(bond, tip));
                if (sip == targets[i]) {
                        if (bond_has_this_ip(bond, tip))
                                slave->last_arp_rx = jiffies;
                        return;
                }
        }
}

static int bond_arp_rcv(const struct sk_buff *skb, struct bonding *bond,
                        struct slave *slave)
{
        struct arphdr *arp = (struct arphdr *)skb->data;
        unsigned char *arp_ptr;
        __be32 sip, tip;
        int alen;

        if (skb->protocol != __cpu_to_be16(ETH_P_ARP))
                return RX_HANDLER_ANOTHER;

        read_lock(&bond->lock);
        alen = arp_hdr_len(bond->dev);

        pr_debug("bond_arp_rcv: bond %s skb->dev %s\n",
                 bond->dev->name, skb->dev->name);

        if (alen > skb_headlen(skb)) {
                arp = kmalloc(alen, GFP_ATOMIC);
                if (!arp)
                        goto out_unlock;
                if (skb_copy_bits(skb, 0, arp, alen) < 0)
                        goto out_unlock;
        }

        if (arp->ar_hln != bond->dev->addr_len ||
            skb->pkt_type == PACKET_OTHERHOST ||
            skb->pkt_type == PACKET_LOOPBACK ||
            arp->ar_hrd != htons(ARPHRD_ETHER) ||
            arp->ar_pro != htons(ETH_P_IP) ||
            arp->ar_pln != 4)
                goto out_unlock;

        arp_ptr = (unsigned char *)(arp + 1);
        arp_ptr += bond->dev->addr_len;
        memcpy(&sip, arp_ptr, 4);
        arp_ptr += 4 + bond->dev->addr_len;
        memcpy(&tip, arp_ptr, 4);

        pr_debug("bond_arp_rcv: %s %s/%d av %d sv %d sip %pI4 tip %pI4\n",
                 bond->dev->name, slave->dev->name, bond_slave_state(slave),
                 bond->params.arp_validate, slave_do_arp_validate(bond, slave),
                 &sip, &tip);

        /*
         * Backup slaves won't see the ARP reply, but do come through
         * here for each ARP probe (so we swap the sip/tip to validate
         * the probe).  In a "redundant switch, common router" type of
         * configuration, the ARP probe will (hopefully) travel from
         * the active, through one switch, the router, then the other
         * switch before reaching the backup.
         */
        if (bond_is_active_slave(slave))
                bond_validate_arp(bond, slave, sip, tip);
        else
                bond_validate_arp(bond, slave, tip, sip);

out_unlock:
        read_unlock(&bond->lock);
        if (arp != (struct arphdr *)skb->data)
                kfree(arp);
        return RX_HANDLER_ANOTHER;
}

/*
 * this function is called regularly to monitor each slave's link
 * ensuring that traffic is being sent and received when arp monitoring
 * is used in load-balancing mode. if the adapter has been dormant, then an
 * arp is transmitted to generate traffic. see activebackup_arp_monitor for
 * arp monitoring in active backup mode.
 */
void bond_loadbalance_arp_mon(struct work_struct *work)
{
        struct bonding *bond = container_of(work, struct bonding,
                                            arp_work.work);
        struct slave *slave, *oldcurrent;
        int do_failover = 0;
        int delta_in_ticks, extra_ticks;
        int i;

        read_lock(&bond->lock);

        delta_in_ticks = msecs_to_jiffies(bond->params.arp_interval);
        extra_ticks = delta_in_ticks / 2;

        if (bond->slave_cnt == 0)
                goto re_arm;

        read_lock(&bond->curr_slave_lock);
        oldcurrent = bond->curr_active_slave;
        read_unlock(&bond->curr_slave_lock);

        /* see if any of the previous devices are up now (i.e. they have
         * xmt and rcv traffic). the curr_active_slave does not come into
         * the picture unless it is null. also, slave->jiffies is not needed
         * here because we send an arp on each slave and give a slave as
         * long as it needs to get the tx/rx within the delta.
         * TODO: what about up/down delay in arp mode? it wasn't here before
         *       so it can wait
         */
        bond_for_each_slave(bond, slave, i) {
                unsigned long trans_start = dev_trans_start(slave->dev);

                if (slave->link != BOND_LINK_UP) {
                        if (time_in_range(jiffies,
                                trans_start - delta_in_ticks,
                                trans_start + delta_in_ticks + extra_ticks) &&
                            time_in_range(jiffies,
                                slave->dev->last_rx - delta_in_ticks,
                                slave->dev->last_rx + delta_in_ticks + extra_ticks)) {

                                slave->link  = BOND_LINK_UP;
                                bond_set_active_slave(slave);

                                /* primary_slave has no meaning in round-robin
                                 * mode. the window of a slave being up and
                                 * curr_active_slave being null after enslaving
                                 * is closed.
                                 */
                                if (!oldcurrent) {
                                        pr_info("%s: link status definitely up for interface %s, ",
                                                bond->dev->name,
                                                slave->dev->name);
                                        do_failover = 1;
                                } else {
                                        pr_info("%s: interface %s is now up\n",
                                                bond->dev->name,
                                                slave->dev->name);
                                }
                        }
                } else {
                        /* slave->link == BOND_LINK_UP */

                        /* not all switches will respond to an arp request
                         * when the source ip is 0, so don't take the link down
                         * if we don't know our ip yet
                         */
                        if (!time_in_range(jiffies,
                                trans_start - delta_in_ticks,
                                trans_start + 2 * delta_in_ticks + extra_ticks) ||
                            !time_in_range(jiffies,
                                slave->dev->last_rx - delta_in_ticks,
                                slave->dev->last_rx + 2 * delta_in_ticks + extra_ticks)) {

                                slave->link  = BOND_LINK_DOWN;
                                bond_set_backup_slave(slave);

                                if (slave->link_failure_count < UINT_MAX)
                                        slave->link_failure_count++;

                                pr_info("%s: interface %s is now down.\n",
                                        bond->dev->name,
                                        slave->dev->name);

                                if (slave == oldcurrent)
                                        do_failover = 1;
                        }
                }

                /* note: if switch is in round-robin mode, all links
                 * must tx arp to ensure all links rx an arp - otherwise
                 * links may oscillate or not come up at all; if switch is
                 * in something like xor mode, there is nothing we can
                 * do - all replies will be rx'ed on same link causing slaves
                 * to be unstable during low/no traffic periods
                 */
                if (IS_UP(slave->dev))
                        bond_arp_send_all(bond, slave);
        }

        if (do_failover) {
                block_netpoll_tx();
                write_lock_bh(&bond->curr_slave_lock);

                bond_select_active_slave(bond);

                write_unlock_bh(&bond->curr_slave_lock);
                unblock_netpoll_tx();
        }

re_arm:
        if (bond->params.arp_interval)
                queue_delayed_work(bond->wq, &bond->arp_work, delta_in_ticks);

        read_unlock(&bond->lock);
}

/*
 * Called to inspect slaves for active-backup mode ARP monitor link state
 * changes.  Sets new_link in slaves to specify what action should take
 * place for the slave.  Returns 0 if no changes are found, >0 if changes
 * to link states must be committed.
 *
 * Called with bond->lock held for read.
 */
static int bond_ab_arp_inspect(struct bonding *bond, int delta_in_ticks)
{
        struct slave *slave;
        int i, commit = 0;
        unsigned long trans_start;
        int extra_ticks;

        /* All the time comparisons below need some extra time. Otherwise, on
         * fast networks the ARP probe/reply may arrive within the same jiffy
         * as it was sent.  Then, the next time the ARP monitor is run, one
         * arp_interval will already have passed in the comparisons.
         */
        extra_ticks = delta_in_ticks / 2;

        bond_for_each_slave(bond, slave, i) {
                slave->new_link = BOND_LINK_NOCHANGE;

                if (slave->link != BOND_LINK_UP) {
                        if (time_in_range(jiffies,
                                slave_last_rx(bond, slave) - delta_in_ticks,
                                slave_last_rx(bond, slave) + delta_in_ticks + extra_ticks)) {

                                slave->new_link = BOND_LINK_UP;
                                commit++;
                        }

                        continue;
                }

                /*
                 * Give slaves 2*delta after being enslaved or made
                 * active.  This avoids bouncing, as the last receive
                 * times need a full ARP monitor cycle to be updated.
                 */
                if (time_in_range(jiffies,
                                  slave->jiffies - delta_in_ticks,
                                  slave->jiffies + 2 * delta_in_ticks + extra_ticks))
                        continue;

                /*
                 * Backup slave is down if:
                 * - No current_arp_slave AND
                 * - more than 3*delta since last receive AND
                 * - the bond has an IP address
                 *
                 * Note: a non-null current_arp_slave indicates
                 * the curr_active_slave went down and we are
                 * searching for a new one; under this condition
                 * we only take the curr_active_slave down - this
                 * gives each slave a chance to tx/rx traffic
                 * before being taken out
                 */
                if (!bond_is_active_slave(slave) &&
                    !bond->current_arp_slave &&
                    !time_in_range(jiffies,
                        slave_last_rx(bond, slave) - delta_in_ticks,
                        slave_last_rx(bond, slave) + 3 * delta_in_ticks + extra_ticks)) {

                        slave->new_link = BOND_LINK_DOWN;
                        commit++;
                }

                /*
                 * Active slave is down if:
                 * - more than 2*delta since transmitting OR
                 * - (more than 2*delta since receive AND
                 *    the bond has an IP address)

                 */
                trans_start = dev_trans_start(slave->dev);
                if (bond_is_active_slave(slave) &&
                    (!time_in_range(jiffies,
                        trans_start - delta_in_ticks,
                        trans_start + 2 * delta_in_ticks + extra_ticks) ||
                     !time_in_range(jiffies,
                        slave_last_rx(bond, slave) - delta_in_ticks,
                        slave_last_rx(bond, slave) + 2 * delta_in_ticks + extra_ticks))) {

                        slave->new_link = BOND_LINK_DOWN;
                        commit++;
                }
        }

        return commit;
}

/*
 * Called to commit link state changes noted by inspection step of
 * active-backup mode ARP monitor.
 *
 * Called with RTNL and bond->lock for read.
 */
static void bond_ab_arp_commit(struct bonding *bond, int delta_in_ticks)
{
        struct slave *slave;
        int i;
        unsigned long trans_start;

        bond_for_each_slave(bond, slave, i) {
                switch (slave->new_link) {
                case BOND_LINK_NOCHANGE:
                        continue;

                case BOND_LINK_UP:
                        trans_start = dev_trans_start(slave->dev);
                        if ((!bond->curr_active_slave &&
                             time_in_range(jiffies,
                                           trans_start - delta_in_ticks,
                                           trans_start + delta_in_ticks + delta_in_ticks / 2)) ||
                            bond->curr_active_slave != slave) {
                                slave->link = BOND_LINK_UP;
                                if (bond->current_arp_slave) {
                                        bond_set_slave_inactive_flags(
                                                bond->current_arp_slave);
                                        bond->current_arp_slave = NULL;
                                }

                                pr_info("%s: link status definitely up for interface %s.\n",
                                        bond->dev->name, slave->dev->name);

                                if (!bond->curr_active_slave ||
                                    (slave == bond->primary_slave))
                                        goto do_failover;

                        }

                        continue;

                case BOND_LINK_DOWN:
                        if (slave->link_failure_count < UINT_MAX)
                                slave->link_failure_count++;

                        slave->link = BOND_LINK_DOWN;
                        bond_set_slave_inactive_flags(slave);

                        pr_info("%s: link status definitely down for interface %s, disabling it\n",
                                bond->dev->name, slave->dev->name);

                        if (slave == bond->curr_active_slave) {
                                bond->current_arp_slave = NULL;
                                goto do_failover;
                        }

                        continue;

                default:
                        pr_err("%s: impossible: new_link %d on slave %s\n",
                               bond->dev->name, slave->new_link,
                               slave->dev->name);
                        continue;
                }

do_failover:
                ASSERT_RTNL();
                block_netpoll_tx();
                write_lock_bh(&bond->curr_slave_lock);
                bond_select_active_slave(bond);
                write_unlock_bh(&bond->curr_slave_lock);
                unblock_netpoll_tx();
        }

        bond_set_carrier(bond);
}

/*
 * Send ARP probes for active-backup mode ARP monitor.
 *
 * Called with bond->lock held for read.
 */
static void bond_ab_arp_probe(struct bonding *bond)
{
        struct slave *slave;
        int i;

        read_lock(&bond->curr_slave_lock);

        if (bond->current_arp_slave && bond->curr_active_slave)
                pr_info("PROBE: c_arp %s && cas %s BAD\n",
                        bond->current_arp_slave->dev->name,
                        bond->curr_active_slave->dev->name);

        if (bond->curr_active_slave) {
                bond_arp_send_all(bond, bond->curr_active_slave);
                read_unlock(&bond->curr_slave_lock);
                return;
        }

        read_unlock(&bond->curr_slave_lock);

        /* if we don't have a curr_active_slave, search for the next available
         * backup slave from the current_arp_slave and make it the candidate
         * for becoming the curr_active_slave
         */

        if (!bond->current_arp_slave) {
                bond->current_arp_slave = bond->first_slave;
                if (!bond->current_arp_slave)
                        return;
        }

        bond_set_slave_inactive_flags(bond->current_arp_slave);

        /* search for next candidate */
        bond_for_each_slave_from(bond, slave, i, bond->current_arp_slave->next) {
                if (IS_UP(slave->dev)) {
                        slave->link = BOND_LINK_BACK;
                        bond_set_slave_active_flags(slave);
                        bond_arp_send_all(bond, slave);
                        slave->jiffies = jiffies;
                        bond->current_arp_slave = slave;
                        break;
                }

                /* if the link state is up at this point, we
                 * mark it down - this can happen if we have
                 * simultaneous link failures and
                 * reselect_active_interface doesn't make this
                 * one the current slave so it is still marked
                 * up when it is actually down
                 */
                if (slave->link == BOND_LINK_UP) {
                        slave->link = BOND_LINK_DOWN;
                        if (slave->link_failure_count < UINT_MAX)
                                slave->link_failure_count++;

                        bond_set_slave_inactive_flags(slave);

                        pr_info("%s: backup interface %s is now down.\n",
                                bond->dev->name, slave->dev->name);
                }
        }
}

void bond_activebackup_arp_mon(struct work_struct *work)
{
        struct bonding *bond = container_of(work, struct bonding,
                                            arp_work.work);
        bool should_notify_peers = false;
        int delta_in_ticks;

        read_lock(&bond->lock);

        delta_in_ticks = msecs_to_jiffies(bond->params.arp_interval);

        if (bond->slave_cnt == 0)
                goto re_arm;

        should_notify_peers = bond_should_notify_peers(bond);

        if (bond_ab_arp_inspect(bond, delta_in_ticks)) {
                read_unlock(&bond->lock);

                /* Race avoidance with bond_close flush of workqueue */
                if (!rtnl_trylock()) {
                        read_lock(&bond->lock);
                        delta_in_ticks = 1;
                        should_notify_peers = false;
                        goto re_arm;
                }

                read_lock(&bond->lock);

                bond_ab_arp_commit(bond, delta_in_ticks);

                read_unlock(&bond->lock);
                rtnl_unlock();
                read_lock(&bond->lock);
        }

        bond_ab_arp_probe(bond);

re_arm:
        if (bond->params.arp_interval)
                queue_delayed_work(bond->wq, &bond->arp_work, delta_in_ticks);

        read_unlock(&bond->lock);

        if (should_notify_peers) {
                if (!rtnl_trylock()) {
                        read_lock(&bond->lock);
                        bond->send_peer_notif++;
                        read_unlock(&bond->lock);
                        return;
                }
                call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, bond->dev);
                rtnl_unlock();
        }
}

/*-------------------------- netdev event handling --------------------------*/

/*
 * Change device name
 */
static int bond_event_changename(struct bonding *bond)
{
        bond_remove_proc_entry(bond);
        bond_create_proc_entry(bond);

        bond_debug_reregister(bond);

        return NOTIFY_DONE;
}

static int bond_master_netdev_event(unsigned long event,
                                    struct net_device *bond_dev)
{
        struct bonding *event_bond = netdev_priv(bond_dev);

        switch (event) {
        case NETDEV_CHANGENAME:
                return bond_event_changename(event_bond);
        case NETDEV_UNREGISTER:
                bond_remove_proc_entry(event_bond);
                break;
        case NETDEV_REGISTER:
                bond_create_proc_entry(event_bond);
                break;
        default:
                break;
        }

        return NOTIFY_DONE;
}

static int bond_slave_netdev_event(unsigned long event,
                                   struct net_device *slave_dev)
{
        struct net_device *bond_dev = slave_dev->master;
        struct bonding *bond = netdev_priv(bond_dev);
        struct slave *slave = NULL;

        switch (event) {
        case NETDEV_UNREGISTER:
                if (bond_dev) {
                        if (bond->setup_by_slave)
                                bond_release_and_destroy(bond_dev, slave_dev);
                        else
                                bond_release(bond_dev, slave_dev);
                }
                break;
        case NETDEV_UP:
        case NETDEV_CHANGE:
                slave = bond_get_slave_by_dev(bond, slave_dev);
                if (slave) {
                        u32 old_speed = slave->speed;
                        u8  old_duplex = slave->duplex;

                        bond_update_speed_duplex(slave);

                        if (bond->params.mode == BOND_MODE_8023AD) {
                                if (old_speed != slave->speed)
                                        bond_3ad_adapter_speed_changed(slave);
                                if (old_duplex != slave->duplex)
                                        bond_3ad_adapter_duplex_changed(slave);
                        }
                }

                break;
        case NETDEV_DOWN:
                /*
                 * ... Or is it this?
                 */
                break;
        case NETDEV_CHANGEMTU:
                /*
                 * TODO: Should slaves be allowed to
                 * independently alter their MTU?  For
                 * an active-backup bond, slaves need
                 * not be the same type of device, so
                 * MTUs may vary.  For other modes,
                 * slaves arguably should have the
                 * same MTUs. To do this, we'd need to
                 * take over the slave's change_mtu
                 * function for the duration of their
                 * servitude.
                 */
                break;
        case NETDEV_CHANGENAME:
                /*
                 * TODO: handle changing the primary's name
                 */
                break;
        case NETDEV_FEAT_CHANGE:
                bond_compute_features(bond);
                break;
        default:
                break;
        }

        return NOTIFY_DONE;
}

/*
 * bond_netdev_event: handle netdev notifier chain events.
 *
 * This function receives events for the netdev chain.  The caller (an
 * ioctl handler calling blocking_notifier_call_chain) holds the necessary
 * locks for us to safely manipulate the slave devices (RTNL lock,
 * dev_probe_lock).
 */
static int bond_netdev_event(struct notifier_block *this,
                             unsigned long event, void *ptr)
{
        struct net_device *event_dev = (struct net_device *)ptr;

        pr_debug("event_dev: %s, event: %lx\n",
                 event_dev ? event_dev->name : "None",
                 event);

        if (!(event_dev->priv_flags & IFF_BONDING))
                return NOTIFY_DONE;

        if (event_dev->flags & IFF_MASTER) {
                pr_debug("IFF_MASTER\n");
                return bond_master_netdev_event(event, event_dev);
        }

        if (event_dev->flags & IFF_SLAVE) {
                pr_debug("IFF_SLAVE\n");
                return bond_slave_netdev_event(event, event_dev);
        }

        return NOTIFY_DONE;
}

static struct notifier_block bond_netdev_notifier = {
        .notifier_call = bond_netdev_event,
};

/*---------------------------- Hashing Policies -----------------------------*/

/*
 * Hash for the output device based upon layer 2 data
 */
static int bond_xmit_hash_policy_l2(struct sk_buff *skb, int count)
{
        struct ethhdr *data = (struct ethhdr *)skb->data;

        if (skb_headlen(skb) >= offsetof(struct ethhdr, h_proto))
                return (data->h_dest[5] ^ data->h_source[5]) % count;

        return 0;
}

/*
 * Hash for the output device based upon layer 2 and layer 3 data. If
 * the packet is not IP, fall back on bond_xmit_hash_policy_l2()
 */
static int bond_xmit_hash_policy_l23(struct sk_buff *skb, int count)
{
        struct ethhdr *data = (struct ethhdr *)skb->data;
        struct iphdr *iph;
        struct ipv6hdr *ipv6h;
        u32 v6hash;
        __be32 *s, *d;

        if (skb->protocol == htons(ETH_P_IP) &&
            skb_network_header_len(skb) >= sizeof(*iph)) {
                iph = ip_hdr(skb);
                return ((ntohl(iph->saddr ^ iph->daddr) & 0xffff) ^
                        (data->h_dest[5] ^ data->h_source[5])) % count;
        } else if (skb->protocol == htons(ETH_P_IPV6) &&
                   skb_network_header_len(skb) >= sizeof(*ipv6h)) {
                ipv6h = ipv6_hdr(skb);
                s = &ipv6h->saddr.s6_addr32[0];
                d = &ipv6h->daddr.s6_addr32[0];
                v6hash = (s[1] ^ d[1]) ^ (s[2] ^ d[2]) ^ (s[3] ^ d[3]);
                v6hash ^= (v6hash >> 24) ^ (v6hash >> 16) ^ (v6hash >> 8);
                return (v6hash ^ data->h_dest[5] ^ data->h_source[5]) % count;
        }

        return bond_xmit_hash_policy_l2(skb, count);
}

/*
 * Hash for the output device based upon layer 3 and layer 4 data. If
 * the packet is a frag or not TCP or UDP, just use layer 3 data.  If it is
 * altogether not IP, fall back on bond_xmit_hash_policy_l2()
 */
static int bond_xmit_hash_policy_l34(struct sk_buff *skb, int count)
{
        u32 layer4_xor = 0;
        struct iphdr *iph;
        struct ipv6hdr *ipv6h;
        __be32 *s, *d;
        __be16 *layer4hdr;

        if (skb->protocol == htons(ETH_P_IP) &&
            skb_network_header_len(skb) >= sizeof(*iph)) {
                iph = ip_hdr(skb);
                if (!ip_is_fragment(iph) &&
                    (iph->protocol == IPPROTO_TCP ||
                     iph->protocol == IPPROTO_UDP) &&
                    (skb_headlen(skb) - skb_network_offset(skb) >=
                     iph->ihl * sizeof(u32) + sizeof(*layer4hdr) * 2)) {
                        layer4hdr = (__be16 *)((u32 *)iph + iph->ihl);
                        layer4_xor = ntohs(*layer4hdr ^ *(layer4hdr + 1));
                }
                return (layer4_xor ^
                        ((ntohl(iph->saddr ^ iph->daddr)) & 0xffff)) % count;
        } else if (skb->protocol == htons(ETH_P_IPV6) &&
                   skb_network_header_len(skb) >= sizeof(*ipv6h)) {
                ipv6h = ipv6_hdr(skb);
                if ((ipv6h->nexthdr == IPPROTO_TCP ||
                     ipv6h->nexthdr == IPPROTO_UDP) &&
                    (skb_headlen(skb) - skb_network_offset(skb) >=
                     sizeof(*ipv6h) + sizeof(*layer4hdr) * 2)) {
                        layer4hdr = (__be16 *)(ipv6h + 1);
                        layer4_xor = ntohs(*layer4hdr ^ *(layer4hdr + 1));
                }
                s = &ipv6h->saddr.s6_addr32[0];
                d = &ipv6h->daddr.s6_addr32[0];
                layer4_xor ^= (s[1] ^ d[1]) ^ (s[2] ^ d[2]) ^ (s[3] ^ d[3]);
                layer4_xor ^= (layer4_xor >> 24) ^ (layer4_xor >> 16) ^
                               (layer4_xor >> 8);
                return layer4_xor % count;
        }

        return bond_xmit_hash_policy_l2(skb, count);
}

/*-------------------------- Device entry points ----------------------------*/

static void bond_work_init_all(struct bonding *bond)
{
        INIT_DELAYED_WORK(&bond->mcast_work,
                          bond_resend_igmp_join_requests_delayed);
        INIT_DELAYED_WORK(&bond->alb_work, bond_alb_monitor);
        INIT_DELAYED_WORK(&bond->mii_work, bond_mii_monitor);
        if (bond->params.mode == BOND_MODE_ACTIVEBACKUP)
                INIT_DELAYED_WORK(&bond->arp_work, bond_activebackup_arp_mon);
        else
                INIT_DELAYED_WORK(&bond->arp_work, bond_loadbalance_arp_mon);
        INIT_DELAYED_WORK(&bond->ad_work, bond_3ad_state_machine_handler);
}

static void bond_work_cancel_all(struct bonding *bond)
{
        cancel_delayed_work_sync(&bond->mii_work);
        cancel_delayed_work_sync(&bond->arp_work);
        cancel_delayed_work_sync(&bond->alb_work);
        cancel_delayed_work_sync(&bond->ad_work);
        cancel_delayed_work_sync(&bond->mcast_work);
}

static int bond_open(struct net_device *bond_dev)
{
        struct bonding *bond = netdev_priv(bond_dev);
        struct slave *slave;
        int i;

        /* reset slave->backup and slave->inactive */
        read_lock(&bond->lock);
        if (bond->slave_cnt > 0) {
                read_lock(&bond->curr_slave_lock);
                bond_for_each_slave(bond, slave, i) {
                        if ((bond->params.mode == BOND_MODE_ACTIVEBACKUP)
                                && (slave != bond->curr_active_slave)) {
                                bond_set_slave_inactive_flags(slave);
                        } else {
                                bond_set_slave_active_flags(slave);
                        }
                }
                read_unlock(&bond->curr_slave_lock);
        }
        read_unlock(&bond->lock);

        bond_work_init_all(bond);

        if (bond_is_lb(bond)) {
                /* bond_alb_initialize must be called before the timer
                 * is started.
                 */
                if (bond_alb_initialize(bond, (bond->params.mode == BOND_MODE_ALB)))
                        return -ENOMEM;
                queue_delayed_work(bond->wq, &bond->alb_work, 0);
        }

        if (bond->params.miimon)  /* link check interval, in milliseconds. */
                queue_delayed_work(bond->wq, &bond->mii_work, 0);

        if (bond->params.arp_interval) {  /* arp interval, in milliseconds. */
                queue_delayed_work(bond->wq, &bond->arp_work, 0);
                if (bond->params.arp_validate)
                        bond->recv_probe = bond_arp_rcv;
        }

        if (bond->params.mode == BOND_MODE_8023AD) {
                queue_delayed_work(bond->wq, &bond->ad_work, 0);
                /* register to receive LACPDUs */
                bond->recv_probe = bond_3ad_lacpdu_recv;
                bond_3ad_initiate_agg_selection(bond, 1);
        }

        return 0;
}

static int bond_close(struct net_device *bond_dev)
{
        struct bonding *bond = netdev_priv(bond_dev);

        write_lock_bh(&bond->lock);
        bond->send_peer_notif = 0;
        write_unlock_bh(&bond->lock);

        bond_work_cancel_all(bond);
        if (bond_is_lb(bond)) {
                /* Must be called only after all
                 * slaves have been released
                 */
                bond_alb_deinitialize(bond);
        }
        bond->recv_probe = NULL;

        return 0;
}

static struct rtnl_link_stats64 *bond_get_stats(struct net_device *bond_dev,
                                                struct rtnl_link_stats64 *stats)
{
        struct bonding *bond = netdev_priv(bond_dev);
        struct rtnl_link_stats64 temp;
        struct slave *slave;
        int i;

        memset(stats, 0, sizeof(*stats));

        read_lock_bh(&bond->lock);

        bond_for_each_slave(bond, slave, i) {
                const struct rtnl_link_stats64 *sstats =
                        dev_get_stats(slave->dev, &temp);

                stats->rx_packets += sstats->rx_packets;
                stats->rx_bytes += sstats->rx_bytes;
                stats->rx_errors += sstats->rx_errors;
                stats->rx_dropped += sstats->rx_dropped;

                stats->tx_packets += sstats->tx_packets;
                stats->tx_bytes += sstats->tx_bytes;
                stats->tx_errors += sstats->tx_errors;
                stats->tx_dropped += sstats->tx_dropped;

                stats->multicast += sstats->multicast;
                stats->collisions += sstats->collisions;

                stats->rx_length_errors += sstats->rx_length_errors;
                stats->rx_over_errors += sstats->rx_over_errors;
                stats->rx_crc_errors += sstats->rx_crc_errors;
                stats->rx_frame_errors += sstats->rx_frame_errors;
                stats->rx_fifo_errors += sstats->rx_fifo_errors;
                stats->rx_missed_errors += sstats->rx_missed_errors;

                stats->tx_aborted_errors += sstats->tx_aborted_errors;
                stats->tx_carrier_errors += sstats->tx_carrier_errors;
                stats->tx_fifo_errors += sstats->tx_fifo_errors;
                stats->tx_heartbeat_errors += sstats->tx_heartbeat_errors;
                stats->tx_window_errors += sstats->tx_window_errors;
        }

        read_unlock_bh(&bond->lock);

        return stats;
}

static int bond_do_ioctl(struct net_device *bond_dev, struct ifreq *ifr, int cmd)
{
        struct net_device *slave_dev = NULL;
        struct ifbond k_binfo;
        struct ifbond __user *u_binfo = NULL;
        struct ifslave k_sinfo;
        struct ifslave __user *u_sinfo = NULL;
        struct mii_ioctl_data *mii = NULL;
        int res = 0;

        pr_debug("bond_ioctl: master=%s, cmd=%d\n", bond_dev->name, cmd);

        switch (cmd) {
        case SIOCGMIIPHY:
                mii = if_mii(ifr);
                if (!mii)
                        return -EINVAL;

                mii->phy_id = 0;
                /* Fall Through */
        case SIOCGMIIREG:
                /*
                 * We do this again just in case we were called by SIOCGMIIREG
                 * instead of SIOCGMIIPHY.
                 */
                mii = if_mii(ifr);
                if (!mii)
                        return -EINVAL;


                if (mii->reg_num == 1) {
                        struct bonding *bond = netdev_priv(bond_dev);
                        mii->val_out = 0;
                        read_lock(&bond->lock);
                        read_lock(&bond->curr_slave_lock);
                        if (netif_carrier_ok(bond->dev))
                                mii->val_out = BMSR_LSTATUS;

                        read_unlock(&bond->curr_slave_lock);
                        read_unlock(&bond->lock);
                }

                return 0;
        case BOND_INFO_QUERY_OLD:
        case SIOCBONDINFOQUERY:
                u_binfo = (struct ifbond __user *)ifr->ifr_data;

                if (copy_from_user(&k_binfo, u_binfo, sizeof(ifbond)))
                        return -EFAULT;

                res = bond_info_query(bond_dev, &k_binfo);
                if (res == 0 &&
                    copy_to_user(u_binfo, &k_binfo, sizeof(ifbond)))
                        return -EFAULT;

                return res;
        case BOND_SLAVE_INFO_QUERY_OLD:
        case SIOCBONDSLAVEINFOQUERY:
                u_sinfo = (struct ifslave __user *)ifr->ifr_data;

                if (copy_from_user(&k_sinfo, u_sinfo, sizeof(ifslave)))
                        return -EFAULT;

                res = bond_slave_info_query(bond_dev, &k_sinfo);
                if (res == 0 &&
                    copy_to_user(u_sinfo, &k_sinfo, sizeof(ifslave)))
                        return -EFAULT;

                return res;
        default:
                /* Go on */
                break;
        }

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

        slave_dev = dev_get_by_name(dev_net(bond_dev), ifr->ifr_slave);

        pr_debug("slave_dev=%p:\n", slave_dev);

        if (!slave_dev)
                res = -ENODEV;
        else {
                pr_debug("slave_dev->name=%s:\n", slave_dev->name);
                switch (cmd) {
                case BOND_ENSLAVE_OLD:
                case SIOCBONDENSLAVE:
                        res = bond_enslave(bond_dev, slave_dev);
                        break;
                case BOND_RELEASE_OLD:
                case SIOCBONDRELEASE:
                        res = bond_release(bond_dev, slave_dev);
                        break;
                case BOND_SETHWADDR_OLD:
                case SIOCBONDSETHWADDR:
                        res = bond_sethwaddr(bond_dev, slave_dev);
                        break;
                case BOND_CHANGE_ACTIVE_OLD:
                case SIOCBONDCHANGEACTIVE:
                        res = bond_ioctl_change_active(bond_dev, slave_dev);
                        break;
                default:
                        res = -EOPNOTSUPP;
                }

                dev_put(slave_dev);
        }

        return res;
}

static bool bond_addr_in_mc_list(unsigned char *addr,
                                 struct netdev_hw_addr_list *list,
                                 int addrlen)
{
        struct netdev_hw_addr *ha;

        netdev_hw_addr_list_for_each(ha, list)
                if (!memcmp(ha->addr, addr, addrlen))
                        return true;

        return false;
}

static void bond_change_rx_flags(struct net_device *bond_dev, int change)
{
        struct bonding *bond = netdev_priv(bond_dev);

        if (change & IFF_PROMISC)
                bond_set_promiscuity(bond,
                                     bond_dev->flags & IFF_PROMISC ? 1 : -1);

        if (change & IFF_ALLMULTI)
                bond_set_allmulti(bond,
                                  bond_dev->flags & IFF_ALLMULTI ? 1 : -1);
}

static void bond_set_multicast_list(struct net_device *bond_dev)
{
        struct bonding *bond = netdev_priv(bond_dev);
        struct netdev_hw_addr *ha;
        bool found;

        read_lock(&bond->lock);

        /* looking for addresses to add to slaves' mc list */
        netdev_for_each_mc_addr(ha, bond_dev) {
                found = bond_addr_in_mc_list(ha->addr, &bond->mc_list,
                                             bond_dev->addr_len);
                if (!found)
                        bond_mc_add(bond, ha->addr);
        }

        /* looking for addresses to delete from slaves' list */
        netdev_hw_addr_list_for_each(ha, &bond->mc_list) {
                found = bond_addr_in_mc_list(ha->addr, &bond_dev->mc,
                                             bond_dev->addr_len);
                if (!found)
                        bond_mc_del(bond, ha->addr);
        }

        /* save master's multicast list */
        __hw_addr_flush(&bond->mc_list);
        __hw_addr_add_multiple(&bond->mc_list, &bond_dev->mc,
                               bond_dev->addr_len, NETDEV_HW_ADDR_T_MULTICAST);

        read_unlock(&bond->lock);
}

static int bond_neigh_init(struct neighbour *n)
{
        struct bonding *bond = netdev_priv(n->dev);
        struct slave *slave = bond->first_slave;
        const struct net_device_ops *slave_ops;
        struct neigh_parms parms;
        int ret;

        if (!slave)
                return 0;

        slave_ops = slave->dev->netdev_ops;

        if (!slave_ops->ndo_neigh_setup)
                return 0;

        parms.neigh_setup = NULL;
        parms.neigh_cleanup = NULL;
        ret = slave_ops->ndo_neigh_setup(slave->dev, &parms);
        if (ret)
                return ret;

        /*
         * Assign slave's neigh_cleanup to neighbour in case cleanup is called
         * after the last slave has been detached.  Assumes that all slaves
         * utilize the same neigh_cleanup (true at this writing as only user
         * is ipoib).
         */
        n->parms->neigh_cleanup = parms.neigh_cleanup;

        if (!parms.neigh_setup)
                return 0;

        return parms.neigh_setup(n);
}

/*
 * The bonding ndo_neigh_setup is called at init time beofre any
 * slave exists. So we must declare proxy setup function which will
 * be used at run time to resolve the actual slave neigh param setup.
 */
static int bond_neigh_setup(struct net_device *dev,
                            struct neigh_parms *parms)
{
        parms->neigh_setup   = bond_neigh_init;

        return 0;
}

/*
 * Change the MTU of all of a master's slaves to match the master
 */
static int bond_change_mtu(struct net_device *bond_dev, int new_mtu)
{
        struct bonding *bond = netdev_priv(bond_dev);
        struct slave *slave, *stop_at;
        int res = 0;
        int i;

        pr_debug("bond=%p, name=%s, new_mtu=%d\n", bond,
                 (bond_dev ? bond_dev->name : "None"), new_mtu);

        /* Can't hold bond->lock with bh disabled here since
         * some base drivers panic. On the other hand we can't
         * hold bond->lock without bh disabled because we'll
         * deadlock. The only solution is to rely on the fact
         * that we're under rtnl_lock here, and the slaves
         * list won't change. This doesn't solve the problem
         * of setting the slave's MTU while it is
         * transmitting, but the assumption is that the base
         * driver can handle that.
         *
         * TODO: figure out a way to safely iterate the slaves
         * list, but without holding a lock around the actual
         * call to the base driver.
         */

        bond_for_each_slave(bond, slave, i) {
                pr_debug("s %p s->p %p c_m %p\n",
                         slave,
                         slave->prev,
                         slave->dev->netdev_ops->ndo_change_mtu);

                res = dev_set_mtu(slave->dev, new_mtu);

                if (res) {
                        /* If we failed to set the slave's mtu to the new value
                         * we must abort the operation even in ACTIVE_BACKUP
                         * mode, because if we allow the backup slaves to have
                         * different mtu values than the active slave we'll
                         * need to change their mtu when doing a failover. That
                         * means changing their mtu from timer context, which
                         * is probably not a good idea.
                         */
                        pr_debug("err %d %s\n", res, slave->dev->name);
                        goto unwind;
                }
        }

        bond_dev->mtu = new_mtu;

        return 0;

unwind:
        /* unwind from head to the slave that failed */
        stop_at = slave;
        bond_for_each_slave_from_to(bond, slave, i, bond->first_slave, stop_at) {
                int tmp_res;

                tmp_res = dev_set_mtu(slave->dev, bond_dev->mtu);
                if (tmp_res) {
                        pr_debug("unwind err %d dev %s\n",
                                 tmp_res, slave->dev->name);
                }
        }

        return res;
}

/*
 * Change HW address
 *
 * Note that many devices must be down to change the HW address, and
 * downing the master releases all slaves.  We can make bonds full of
 * bonding devices to test this, however.
 */
static int bond_set_mac_address(struct net_device *bond_dev, void *addr)
{
        struct bonding *bond = netdev_priv(bond_dev);
        struct sockaddr *sa = addr, tmp_sa;
        struct slave *slave, *stop_at;
        int res = 0;
        int i;

        if (bond->params.mode == BOND_MODE_ALB)
                return bond_alb_set_mac_address(bond_dev, addr);


        pr_debug("bond=%p, name=%s\n",
                 bond, bond_dev ? bond_dev->name : "None");

        /*
         * If fail_over_mac is set to active, do nothing and return
         * success.  Returning an error causes ifenslave to fail.
         */
        if (bond->params.fail_over_mac == BOND_FOM_ACTIVE)
                return 0;

        if (!is_valid_ether_addr(sa->sa_data))
                return -EADDRNOTAVAIL;

        /* Can't hold bond->lock with bh disabled here since
         * some base drivers panic. On the other hand we can't
         * hold bond->lock without bh disabled because we'll
         * deadlock. The only solution is to rely on the fact
         * that we're under rtnl_lock here, and the slaves
         * list won't change. This doesn't solve the problem
         * of setting the slave's hw address while it is
         * transmitting, but the assumption is that the base
         * driver can handle that.
         *
         * TODO: figure out a way to safely iterate the slaves
         * list, but without holding a lock around the actual
         * call to the base driver.
         */

        bond_for_each_slave(bond, slave, i) {
                const struct net_device_ops *slave_ops = slave->dev->netdev_ops;
                pr_debug("slave %p %s\n", slave, slave->dev->name);

                if (slave_ops->ndo_set_mac_address == NULL) {
                        res = -EOPNOTSUPP;
                        pr_debug("EOPNOTSUPP %s\n", slave->dev->name);
                        goto unwind;
                }

                res = dev_set_mac_address(slave->dev, addr);
                if (res) {
                        /* TODO: consider downing the slave
                         * and retry ?
                         * User should expect communications
                         * breakage anyway until ARP finish
                         * updating, so...
                         */
                        pr_debug("err %d %s\n", res, slave->dev->name);
                        goto unwind;
                }
        }

        /* success */
        memcpy(bond_dev->dev_addr, sa->sa_data, bond_dev->addr_len);
        return 0;

unwind:
        memcpy(tmp_sa.sa_data, bond_dev->dev_addr, bond_dev->addr_len);
        tmp_sa.sa_family = bond_dev->type;

        /* unwind from head to the slave that failed */
        stop_at = slave;
        bond_for_each_slave_from_to(bond, slave, i, bond->first_slave, stop_at) {
                int tmp_res;

                tmp_res = dev_set_mac_address(slave->dev, &tmp_sa);
                if (tmp_res) {
                        pr_debug("unwind err %d dev %s\n",
                                 tmp_res, slave->dev->name);
                }
        }

        return res;
}

static int bond_xmit_roundrobin(struct sk_buff *skb, struct net_device *bond_dev)
{
        struct bonding *bond = netdev_priv(bond_dev);
        struct slave *slave, *start_at;
        int i, slave_no, res = 1;
        struct iphdr *iph = ip_hdr(skb);

        /*
         * Start with the curr_active_slave that joined the bond as the
         * default for sending IGMP traffic.  For failover purposes one
         * needs to maintain some consistency for the interface that will
         * send the join/membership reports.  The curr_active_slave found
         * will send all of this type of traffic.
         */
        if ((iph->protocol == IPPROTO_IGMP) &&
            (skb->protocol == htons(ETH_P_IP))) {

                read_lock(&bond->curr_slave_lock);
                slave = bond->curr_active_slave;
                read_unlock(&bond->curr_slave_lock);