bond_main.c

/*
 * 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/system.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/proc_fs.h>
#include <linux/seq_file.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 <net/route.h>
#include <net/net_namespace.h>
#include <net/netns/generic.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 num_grat_arp = 1;
static int num_unsol_na = 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 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 struct bond_params bonding_defaults;

module_param(max_bonds, int, 0);
MODULE_PARM_DESC(max_bonds, "Max number of bonded devices");
module_param(num_grat_arp, int, 0644);
MODULE_PARM_DESC(num_grat_arp, "Number of gratuitous ARP packets to send on failover event");
module_param(num_unsol_na, int, 0644);
MODULE_PARM_DESC(num_unsol_na, "Number of unsolicited IPv6 Neighbor Advertisements packets to send on failover event");
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 "
			    "(slow/fast)");
module_param(ad_select, charp, 0);
MODULE_PARM_DESC(ad_select, "803.ad aggregation selection logic: stable (0, default), bandwidth (1), count (2)");
module_param(xmit_hash_policy, charp, 0);
MODULE_PARM_DESC(xmit_hash_policy, "XOR hashing method: 0 for layer 2 (default)"
				   ", 1 for layer 3+4");
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: none (default), active, backup or 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.  none (default), active or follow");

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

static const char * const version =
	DRV_DESCRIPTION ": v" DRV_VERSION " (" DRV_RELDATE ")\n";

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

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

static 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);

	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);

			if (list_empty(&bond->vlan_list) &&
			    (bond->slave_cnt == 0)) {
				/* Last VLAN removed and no slaves, so
				 * restore block on adding VLANs. This will
				 * be removed once new slaves that are not
				 * VLAN challenged will be added.
				 */
				bond->dev->features |= NETIF_F_VLAN_CHALLENGED;
			}

			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);
	return res;
}

/**
 * bond_has_challenged_slaves
 * @bond: the bond we're working on
 *
 * Searches the slave list. Returns 1 if a vlan challenged slave
 * was found, 0 otherwise.
 *
 * Assumes bond->lock is held.
 */
static int bond_has_challenged_slaves(struct bonding *bond)
{
	struct slave *slave;
	int i;

	bond_for_each_slave(bond, slave, i) {
		if (slave->dev->features & NETIF_F_VLAN_CHALLENGED) {
			pr_debug("found VLAN challenged slave - %s\n",
				 slave->dev->name);
			return 1;
		}
	}

	pr_debug("no VLAN challenged slaves found\n");
	return 0;
}

/**
 * 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
 *
 * When the bond gets an skb to transmit that is
 * already hardware accelerated VLAN tagged, and it
 * needs to relay this skb to a slave that is not
 * hw accel capable, the skb needs to be "unaccelerated",
 * i.e. strip the hwaccel tag and re-insert it as part
 * of the payload.
 */
int bond_dev_queue_xmit(struct bonding *bond, struct sk_buff *skb,
			struct net_device *slave_dev)
{
	unsigned short uninitialized_var(vlan_id);

	if (!list_empty(&bond->vlan_list) &&
	    !(slave_dev->features & NETIF_F_HW_VLAN_TX) &&
	    vlan_get_tag(skb, &vlan_id) == 0) {
		skb->dev = slave_dev;
		skb = vlan_put_tag(skb, vlan_id);
		if (!skb) {
			/* vlan_put_tag() frees the skb in case of error,
			 * so return success here so the calling functions
			 * won't attempt to free is again.
			 */
			return 0;
		}
	} else {
		skb->dev = slave_dev;
	}

	skb->priority = 1;
	dev_queue_xmit(skb);

	return 0;
}

/*
 * In the following 3 functions, bond_vlan_rx_register(), 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_register - Propagates registration to slaves
 * @bond_dev: bonding net device that got called
 * @grp: vlan group being registered
 */
static void bond_vlan_rx_register(struct net_device *bond_dev,
				  struct vlan_group *grp)
{
	struct bonding *bond = netdev_priv(bond_dev);
	struct slave *slave;
	int i;

	bond->vlgrp = grp;

	bond_for_each_slave(bond, slave, i) {
		struct net_device *slave_dev = slave->dev;
		const struct net_device_ops *slave_ops = slave_dev->netdev_ops;

		if ((slave_dev->features & NETIF_F_HW_VLAN_RX) &&
		    slave_ops->ndo_vlan_rx_register) {
			slave_ops->ndo_vlan_rx_register(slave_dev, grp);
		}
	}
}

/**
 * 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 void bond_vlan_rx_add_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) {
		struct net_device *slave_dev = slave->dev;
		const struct net_device_ops *slave_ops = slave_dev->netdev_ops;

		if ((slave_dev->features & NETIF_F_HW_VLAN_FILTER) &&
		    slave_ops->ndo_vlan_rx_add_vid) {
			slave_ops->ndo_vlan_rx_add_vid(slave_dev, vid);
		}
	}

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

/**
 * 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 void bond_vlan_rx_kill_vid(struct net_device *bond_dev, uint16_t vid)
{
	struct bonding *bond = netdev_priv(bond_dev);
	struct slave *slave;
	struct net_device *vlan_dev;
	int i, res;

	bond_for_each_slave(bond, slave, i) {
		struct net_device *slave_dev = slave->dev;
		const struct net_device_ops *slave_ops = slave_dev->netdev_ops;

		if ((slave_dev->features & NETIF_F_HW_VLAN_FILTER) &&
		    slave_ops->ndo_vlan_rx_kill_vid) {
			/* Save and then restore vlan_dev in the grp array,
			 * since the slave's driver might clear it.
			 */
			vlan_dev = vlan_group_get_device(bond->vlgrp, vid);
			slave_ops->ndo_vlan_rx_kill_vid(slave_dev, vid);
			vlan_group_set_device(bond->vlgrp, vid, vlan_dev);
		}
	}

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

static void bond_add_vlans_on_slave(struct bonding *bond, struct net_device *slave_dev)
{
	struct vlan_entry *vlan;
	const struct net_device_ops *slave_ops = slave_dev->netdev_ops;

	write_lock_bh(&bond->lock);

	if (list_empty(&bond->vlan_list))
		goto out;

	if ((slave_dev->features & NETIF_F_HW_VLAN_RX) &&
	    slave_ops->ndo_vlan_rx_register)
		slave_ops->ndo_vlan_rx_register(slave_dev, bond->vlgrp);

	if (!(slave_dev->features & NETIF_F_HW_VLAN_FILTER) ||
	    !(slave_ops->ndo_vlan_rx_add_vid))
		goto out;

	list_for_each_entry(vlan, &bond->vlan_list, vlan_list)
		slave_ops->ndo_vlan_rx_add_vid(slave_dev, vlan->vlan_id);

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

static void bond_del_vlans_from_slave(struct bonding *bond,
				      struct net_device *slave_dev)
{
	const struct net_device_ops *slave_ops = slave_dev->netdev_ops;
	struct vlan_entry *vlan;
	struct net_device *vlan_dev;

	write_lock_bh(&bond->lock);

	if (list_empty(&bond->vlan_list))
		goto out;

	if (!(slave_dev->features & NETIF_F_HW_VLAN_FILTER) ||
	    !(slave_ops->ndo_vlan_rx_kill_vid))
		goto unreg;

	list_for_each_entry(vlan, &bond->vlan_list, vlan_list) {
		/* Save and then restore vlan_dev in the grp array,
		 * since the slave's driver might clear it.
		 */
		vlan_dev = vlan_group_get_device(bond->vlgrp, vlan->vlan_id);
		slave_ops->ndo_vlan_rx_kill_vid(slave_dev, vlan->vlan_id);
		vlan_group_set_device(bond->vlgrp, vlan->vlan_id, vlan_dev);
	}

unreg:
	if ((slave_dev->features & NETIF_F_HW_VLAN_RX) &&
	    slave_ops->ndo_vlan_rx_register)
		slave_ops->ndo_vlan_rx_register(slave_dev, NULL);

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

/*------------------------------- 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, fake speed and duplex to 100/Full
 * and return error.
 */
static int bond_update_speed_duplex(struct slave *slave)
{
	struct net_device *slave_dev = slave->dev;
	struct ethtool_cmd etool;
	int res;

	/* Fake speed and duplex */
	slave->speed = SPEED_100;
	slave->duplex = DUPLEX_FULL;

	if (!slave_dev->ethtool_ops || !slave_dev->ethtool_ops->get_settings)
		return -1;

	res = slave_dev->ethtool_ops->get_settings(slave_dev, &etool);
	if (res < 0)
		return -1;

	switch (etool.speed) {
	case SPEED_10:
	case SPEED_100:
	case SPEED_1000:
	case SPEED_10000:
		break;
	default:
		return -1;
	}

	switch (etool.duplex) {
	case DUPLEX_FULL:
	case DUPLEX_HALF:
		break;
	default:
		return -1;
	}

	slave->speed = etool.speed;
	slave->duplex = etool.duplex;

	return 0;
}

/*
 * 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) {
		if (slave_dev->ethtool_ops->get_link) {
			u32 link;

			link = slave_dev->ethtool_ops->get_link(slave_dev);

			return link ? 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);
		}
	}
}


/*
 * 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 in_device *in_dev;
	struct ip_mc_list *im;

	rcu_read_lock();
	in_dev = __in_dev_get_rcu(bond->dev);
	if (in_dev) {
		for (im = in_dev->mc_list; im; im = im->next)
			ip_mc_rejoin_group(im);
	}

	rcu_read_unlock();
}

/*
 * 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_resend_igmp_join_requests(bond);
	}
}

/*
 * 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);
		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;
}

/**
 * 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) {
			bond_set_slave_active_flags(new_active);

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

			bond->send_grat_arp = bond->params.num_grat_arp;
			bond_send_gratuitous_arp(bond);

			bond->send_unsol_na = bond->params.num_unsol_na;
			bond_send_unsolicited_na(bond);

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

			netdev_bonding_change(bond->dev, NETDEV_BONDING_FAILOVER);

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

	/* resend IGMP joins since all were sent on curr_active_slave */
	if (bond->params.mode == BOND_MODE_ROUNDROBIN) {
		bond_resend_igmp_join_requests(bond);
	}
}

/**
 * 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--;
}

/*---------------------------------- 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;
}

#define BOND_VLAN_FEATURES \
	(NETIF_F_VLAN_CHALLENGED | NETIF_F_HW_VLAN_RX | NETIF_F_HW_VLAN_TX | \
	 NETIF_F_HW_VLAN_FILTER)

/*
 * Compute the common dev->feature set available to all slaves.  Some
 * feature bits are managed elsewhere, so preserve those feature bits
 * on the master device.
 */
static int bond_compute_features(struct bonding *bond)
{
	struct slave *slave;
	struct net_device *bond_dev = bond->dev;
	unsigned long features = bond_dev->features;
	unsigned long vlan_features = 0;
	unsigned short max_hard_header_len = max((u16)ETH_HLEN,
						bond_dev->hard_header_len);
	int i;

	features &= ~(NETIF_F_ALL_CSUM | BOND_VLAN_FEATURES);
	features |=  NETIF_F_GSO_MASK | NETIF_F_NO_CSUM;

	if (!bond->first_slave)
		goto done;

	features &= ~NETIF_F_ONE_FOR_ALL;

	vlan_features = bond->first_slave->dev->vlan_features;
	bond_for_each_slave(bond, slave, i) {
		features = netdev_increment_features(features,
						     slave->dev->features,
						     NETIF_F_ONE_FOR_ALL);
		vlan_features = netdev_increment_features(vlan_features,
							slave->dev->vlan_features,
							NETIF_F_ONE_FOR_ALL);
		if (slave->dev->hard_header_len > max_hard_header_len)
			max_hard_header_len = slave->dev->hard_header_len;
	}

done:
	features |= (bond_dev->features & BOND_VLAN_FEATURES);
	bond_dev->features = netdev_fix_features(features, NULL);
	bond_dev->vlan_features = netdev_fix_features(vlan_features, NULL);
	bond_dev->hard_header_len = max_hard_header_len;

	return 0;
}

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;
}

/* 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);