net: ptp: do not reimplement PTP/BPF classifier

[linux/fpc-iii.git] / drivers / net / bonding / bond_alb.c

/*
 * Copyright(c) 1999 - 2004 Intel Corporation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, see <http://www.gnu.org/licenses/>.
 *
 * The full GNU General Public License is included in this distribution in the
 * file called LICENSE.
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/pkt_sched.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/timer.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/if_arp.h>
#include <linux/if_ether.h>
#include <linux/if_bonding.h>
#include <linux/if_vlan.h>
#include <linux/in.h>
#include <net/ipx.h>
#include <net/arp.h>
#include <net/ipv6.h>
#include <asm/byteorder.h>
#include "bonding.h"
#include "bond_alb.h"



#ifndef __long_aligned
#define __long_aligned __attribute__((aligned((sizeof(long)))))
#endif
static const u8 mac_bcast[ETH_ALEN] __long_aligned = {
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff
};
static const u8 mac_v6_allmcast[ETH_ALEN] __long_aligned = {
        0x33, 0x33, 0x00, 0x00, 0x00, 0x01
};
static const int alb_delta_in_ticks = HZ / ALB_TIMER_TICKS_PER_SEC;

#pragma pack(1)
struct learning_pkt {
        u8 mac_dst[ETH_ALEN];
        u8 mac_src[ETH_ALEN];
        __be16 type;
        u8 padding[ETH_ZLEN - ETH_HLEN];
};

struct arp_pkt {
        __be16  hw_addr_space;
        __be16  prot_addr_space;
        u8      hw_addr_len;
        u8      prot_addr_len;
        __be16  op_code;
        u8      mac_src[ETH_ALEN];      /* sender hardware address */
        __be32  ip_src;                 /* sender IP address */
        u8      mac_dst[ETH_ALEN];      /* target hardware address */
        __be32  ip_dst;                 /* target IP address */
};
#pragma pack()

static inline struct arp_pkt *arp_pkt(const struct sk_buff *skb)
{
        return (struct arp_pkt *)skb_network_header(skb);
}

/* Forward declaration */
static void alb_send_learning_packets(struct slave *slave, u8 mac_addr[]);
static void rlb_purge_src_ip(struct bonding *bond, struct arp_pkt *arp);
static void rlb_src_unlink(struct bonding *bond, u32 index);
static void rlb_src_link(struct bonding *bond, u32 ip_src_hash,
                         u32 ip_dst_hash);

static inline u8 _simple_hash(const u8 *hash_start, int hash_size)
{
        int i;
        u8 hash = 0;

        for (i = 0; i < hash_size; i++)
                hash ^= hash_start[i];

        return hash;
}

/*********************** tlb specific functions ***************************/

static inline void _lock_tx_hashtbl_bh(struct bonding *bond)
{
        spin_lock_bh(&(BOND_ALB_INFO(bond).tx_hashtbl_lock));
}

static inline void _unlock_tx_hashtbl_bh(struct bonding *bond)
{
        spin_unlock_bh(&(BOND_ALB_INFO(bond).tx_hashtbl_lock));
}

static inline void _lock_tx_hashtbl(struct bonding *bond)
{
        spin_lock(&(BOND_ALB_INFO(bond).tx_hashtbl_lock));
}

static inline void _unlock_tx_hashtbl(struct bonding *bond)
{
        spin_unlock(&(BOND_ALB_INFO(bond).tx_hashtbl_lock));
}

/* Caller must hold tx_hashtbl lock */
static inline void tlb_init_table_entry(struct tlb_client_info *entry, int save_load)
{
        if (save_load) {
                entry->load_history = 1 + entry->tx_bytes /
                                      BOND_TLB_REBALANCE_INTERVAL;
                entry->tx_bytes = 0;
        }

        entry->tx_slave = NULL;
        entry->next = TLB_NULL_INDEX;
        entry->prev = TLB_NULL_INDEX;
}

static inline void tlb_init_slave(struct slave *slave)
{
        SLAVE_TLB_INFO(slave).load = 0;
        SLAVE_TLB_INFO(slave).head = TLB_NULL_INDEX;
}

/* Caller must hold bond lock for read, BH disabled */
static void __tlb_clear_slave(struct bonding *bond, struct slave *slave,
                         int save_load)
{
        struct tlb_client_info *tx_hash_table;
        u32 index;

        /* clear slave from tx_hashtbl */
        tx_hash_table = BOND_ALB_INFO(bond).tx_hashtbl;

        /* skip this if we've already freed the tx hash table */
        if (tx_hash_table) {
                index = SLAVE_TLB_INFO(slave).head;
                while (index != TLB_NULL_INDEX) {
                        u32 next_index = tx_hash_table[index].next;
                        tlb_init_table_entry(&tx_hash_table[index], save_load);
                        index = next_index;
                }
        }

        tlb_init_slave(slave);
}

/* Caller must hold bond lock for read */
static void tlb_clear_slave(struct bonding *bond, struct slave *slave,
                         int save_load)
{
        _lock_tx_hashtbl_bh(bond);
        __tlb_clear_slave(bond, slave, save_load);
        _unlock_tx_hashtbl_bh(bond);
}

/* Must be called before starting the monitor timer */
static int tlb_initialize(struct bonding *bond)
{
        struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond));
        int size = TLB_HASH_TABLE_SIZE * sizeof(struct tlb_client_info);
        struct tlb_client_info *new_hashtbl;
        int i;

        new_hashtbl = kzalloc(size, GFP_KERNEL);
        if (!new_hashtbl)
                return -1;

        _lock_tx_hashtbl_bh(bond);

        bond_info->tx_hashtbl = new_hashtbl;

        for (i = 0; i < TLB_HASH_TABLE_SIZE; i++)
                tlb_init_table_entry(&bond_info->tx_hashtbl[i], 0);

        _unlock_tx_hashtbl_bh(bond);

        return 0;
}

/* Must be called only after all slaves have been released */
static void tlb_deinitialize(struct bonding *bond)
{
        struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond));

        _lock_tx_hashtbl_bh(bond);

        kfree(bond_info->tx_hashtbl);
        bond_info->tx_hashtbl = NULL;

        _unlock_tx_hashtbl_bh(bond);
}

static long long compute_gap(struct slave *slave)
{
        return (s64) (slave->speed << 20) - /* Convert to Megabit per sec */
               (s64) (SLAVE_TLB_INFO(slave).load << 3); /* Bytes to bits */
}

/* Caller must hold bond lock for read */
static struct slave *tlb_get_least_loaded_slave(struct bonding *bond)
{
        struct slave *slave, *least_loaded;
        struct list_head *iter;
        long long max_gap;

        least_loaded = NULL;
        max_gap = LLONG_MIN;

        /* Find the slave with the largest gap */
        bond_for_each_slave_rcu(bond, slave, iter) {
                if (SLAVE_IS_OK(slave)) {
                        long long gap = compute_gap(slave);

                        if (max_gap < gap) {
                                least_loaded = slave;
                                max_gap = gap;
                        }
                }
        }

        return least_loaded;
}

static struct slave *__tlb_choose_channel(struct bonding *bond, u32 hash_index,
                                                u32 skb_len)
{
        struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond));
        struct tlb_client_info *hash_table;
        struct slave *assigned_slave;

        hash_table = bond_info->tx_hashtbl;
        assigned_slave = hash_table[hash_index].tx_slave;
        if (!assigned_slave) {
                assigned_slave = tlb_get_least_loaded_slave(bond);

                if (assigned_slave) {
                        struct tlb_slave_info *slave_info =
                                &(SLAVE_TLB_INFO(assigned_slave));
                        u32 next_index = slave_info->head;

                        hash_table[hash_index].tx_slave = assigned_slave;
                        hash_table[hash_index].next = next_index;
                        hash_table[hash_index].prev = TLB_NULL_INDEX;

                        if (next_index != TLB_NULL_INDEX)
                                hash_table[next_index].prev = hash_index;

                        slave_info->head = hash_index;
                        slave_info->load +=
                                hash_table[hash_index].load_history;
                }
        }

        if (assigned_slave)
                hash_table[hash_index].tx_bytes += skb_len;

        return assigned_slave;
}

/* Caller must hold bond lock for read */
static struct slave *tlb_choose_channel(struct bonding *bond, u32 hash_index,
                                        u32 skb_len)
{
        struct slave *tx_slave;
        /*
         * We don't need to disable softirq here, becase
         * tlb_choose_channel() is only called by bond_alb_xmit()
         * which already has softirq disabled.
         */
        _lock_tx_hashtbl(bond);
        tx_slave = __tlb_choose_channel(bond, hash_index, skb_len);
        _unlock_tx_hashtbl(bond);
        return tx_slave;
}

/*********************** rlb specific functions ***************************/
static inline void _lock_rx_hashtbl_bh(struct bonding *bond)
{
        spin_lock_bh(&(BOND_ALB_INFO(bond).rx_hashtbl_lock));
}

static inline void _unlock_rx_hashtbl_bh(struct bonding *bond)
{
        spin_unlock_bh(&(BOND_ALB_INFO(bond).rx_hashtbl_lock));
}

static inline void _lock_rx_hashtbl(struct bonding *bond)
{
        spin_lock(&(BOND_ALB_INFO(bond).rx_hashtbl_lock));
}

static inline void _unlock_rx_hashtbl(struct bonding *bond)
{
        spin_unlock(&(BOND_ALB_INFO(bond).rx_hashtbl_lock));
}

/* when an ARP REPLY is received from a client update its info
 * in the rx_hashtbl
 */
static void rlb_update_entry_from_arp(struct bonding *bond, struct arp_pkt *arp)
{
        struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond));
        struct rlb_client_info *client_info;
        u32 hash_index;

        _lock_rx_hashtbl_bh(bond);

        hash_index = _simple_hash((u8 *)&(arp->ip_src), sizeof(arp->ip_src));
        client_info = &(bond_info->rx_hashtbl[hash_index]);

        if ((client_info->assigned) &&
            (client_info->ip_src == arp->ip_dst) &&
            (client_info->ip_dst == arp->ip_src) &&
            (!ether_addr_equal_64bits(client_info->mac_dst, arp->mac_src))) {
                /* update the clients MAC address */
                ether_addr_copy(client_info->mac_dst, arp->mac_src);
                client_info->ntt = 1;
                bond_info->rx_ntt = 1;
        }

        _unlock_rx_hashtbl_bh(bond);
}

static int rlb_arp_recv(const struct sk_buff *skb, struct bonding *bond,
                        struct slave *slave)
{
        struct arp_pkt *arp, _arp;

        if (skb->protocol != cpu_to_be16(ETH_P_ARP))
                goto out;

        arp = skb_header_pointer(skb, 0, sizeof(_arp), &_arp);
        if (!arp)
                goto out;

        /* We received an ARP from arp->ip_src.
         * We might have used this IP address previously (on the bonding host
         * itself or on a system that is bridged together with the bond).
         * However, if arp->mac_src is different than what is stored in
         * rx_hashtbl, some other host is now using the IP and we must prevent
         * sending out client updates with this IP address and the old MAC
         * address.
         * Clean up all hash table entries that have this address as ip_src but
         * have a different mac_src.
         */
        rlb_purge_src_ip(bond, arp);

        if (arp->op_code == htons(ARPOP_REPLY)) {
                /* update rx hash table for this ARP */
                rlb_update_entry_from_arp(bond, arp);
                pr_debug("Server received an ARP Reply from client\n");
        }
out:
        return RX_HANDLER_ANOTHER;
}

/* Caller must hold bond lock for read */
static struct slave *rlb_next_rx_slave(struct bonding *bond)
{
        struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond));
        struct slave *before = NULL, *rx_slave = NULL, *slave;
        struct list_head *iter;
        bool found = false;

        bond_for_each_slave(bond, slave, iter) {
                if (!SLAVE_IS_OK(slave))
                        continue;
                if (!found) {
                        if (!before || before->speed < slave->speed)
                                before = slave;
                } else {
                        if (!rx_slave || rx_slave->speed < slave->speed)
                                rx_slave = slave;
                }
                if (slave == bond_info->rx_slave)
                        found = true;
        }
        /* we didn't find anything after the current or we have something
         * better before and up to the current slave
         */
        if (!rx_slave || (before && rx_slave->speed < before->speed))
                rx_slave = before;

        if (rx_slave)
                bond_info->rx_slave = rx_slave;

        return rx_slave;
}

/* Caller must hold rcu_read_lock() for read */
static struct slave *__rlb_next_rx_slave(struct bonding *bond)
{
        struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond));
        struct slave *before = NULL, *rx_slave = NULL, *slave;
        struct list_head *iter;
        bool found = false;

        bond_for_each_slave_rcu(bond, slave, iter) {
                if (!SLAVE_IS_OK(slave))
                        continue;
                if (!found) {
                        if (!before || before->speed < slave->speed)
                                before = slave;
                } else {
                        if (!rx_slave || rx_slave->speed < slave->speed)
                                rx_slave = slave;
                }
                if (slave == bond_info->rx_slave)
                        found = true;
        }
        /* we didn't find anything after the current or we have something
         * better before and up to the current slave
         */
        if (!rx_slave || (before && rx_slave->speed < before->speed))
                rx_slave = before;

        if (rx_slave)
                bond_info->rx_slave = rx_slave;

        return rx_slave;
}

/* teach the switch the mac of a disabled slave
 * on the primary for fault tolerance
 *
 * Caller must hold bond->curr_slave_lock for write or bond lock for write
 */
static void rlb_teach_disabled_mac_on_primary(struct bonding *bond, u8 addr[])
{
        if (!bond->curr_active_slave)
                return;

        if (!bond->alb_info.primary_is_promisc) {
                if (!dev_set_promiscuity(bond->curr_active_slave->dev, 1))
                        bond->alb_info.primary_is_promisc = 1;
                else
                        bond->alb_info.primary_is_promisc = 0;
        }

        bond->alb_info.rlb_promisc_timeout_counter = 0;

        alb_send_learning_packets(bond->curr_active_slave, addr);
}

/* slave being removed should not be active at this point
 *
 * Caller must hold rtnl.
 */
static void rlb_clear_slave(struct bonding *bond, struct slave *slave)
{
        struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond));
        struct rlb_client_info *rx_hash_table;
        u32 index, next_index;

        /* clear slave from rx_hashtbl */
        _lock_rx_hashtbl_bh(bond);

        rx_hash_table = bond_info->rx_hashtbl;
        index = bond_info->rx_hashtbl_used_head;
        for (; index != RLB_NULL_INDEX; index = next_index) {
                next_index = rx_hash_table[index].used_next;
                if (rx_hash_table[index].slave == slave) {
                        struct slave *assigned_slave = rlb_next_rx_slave(bond);

                        if (assigned_slave) {
                                rx_hash_table[index].slave = assigned_slave;
                                if (!ether_addr_equal_64bits(rx_hash_table[index].mac_dst,
                                                             mac_bcast)) {
                                        bond_info->rx_hashtbl[index].ntt = 1;
                                        bond_info->rx_ntt = 1;
                                        /* A slave has been removed from the
                                         * table because it is either disabled
                                         * or being released. We must retry the
                                         * update to avoid clients from not
                                         * being updated & disconnecting when
                                         * there is stress
                                         */
                                        bond_info->rlb_update_retry_counter =
                                                RLB_UPDATE_RETRY;
                                }
                        } else {  /* there is no active slave */
                                rx_hash_table[index].slave = NULL;
                        }
                }
        }

        _unlock_rx_hashtbl_bh(bond);

        write_lock_bh(&bond->curr_slave_lock);

        if (slave != bond->curr_active_slave)
                rlb_teach_disabled_mac_on_primary(bond, slave->dev->dev_addr);

        write_unlock_bh(&bond->curr_slave_lock);
}

static void rlb_update_client(struct rlb_client_info *client_info)
{
        int i;

        if (!client_info->slave)
                return;

        for (i = 0; i < RLB_ARP_BURST_SIZE; i++) {
                struct sk_buff *skb;

                skb = arp_create(ARPOP_REPLY, ETH_P_ARP,
                                 client_info->ip_dst,
                                 client_info->slave->dev,
                                 client_info->ip_src,
                                 client_info->mac_dst,
                                 client_info->slave->dev->dev_addr,
                                 client_info->mac_dst);
                if (!skb) {
                        pr_err("%s: Error: failed to create an ARP packet\n",
                               client_info->slave->bond->dev->name);
                        continue;
                }

                skb->dev = client_info->slave->dev;

                if (client_info->vlan_id) {
                        skb = vlan_put_tag(skb, htons(ETH_P_8021Q), client_info->vlan_id);
                        if (!skb) {
                                pr_err("%s: Error: failed to insert VLAN tag\n",
                                       client_info->slave->bond->dev->name);
                                continue;
                        }
                }

                arp_xmit(skb);
        }
}

/* sends ARP REPLIES that update the clients that need updating */
static void rlb_update_rx_clients(struct bonding *bond)
{
        struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond));
        struct rlb_client_info *client_info;
        u32 hash_index;

        _lock_rx_hashtbl_bh(bond);

        hash_index = bond_info->rx_hashtbl_used_head;
        for (; hash_index != RLB_NULL_INDEX;
             hash_index = client_info->used_next) {
                client_info = &(bond_info->rx_hashtbl[hash_index]);
                if (client_info->ntt) {
                        rlb_update_client(client_info);
                        if (bond_info->rlb_update_retry_counter == 0)
                                client_info->ntt = 0;
                }
        }

        /* do not update the entries again until this counter is zero so that
         * not to confuse the clients.
         */
        bond_info->rlb_update_delay_counter = RLB_UPDATE_DELAY;

        _unlock_rx_hashtbl_bh(bond);
}

/* The slave was assigned a new mac address - update the clients */
static void rlb_req_update_slave_clients(struct bonding *bond, struct slave *slave)
{
        struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond));
        struct rlb_client_info *client_info;
        int ntt = 0;
        u32 hash_index;

        _lock_rx_hashtbl_bh(bond);

        hash_index = bond_info->rx_hashtbl_used_head;
        for (; hash_index != RLB_NULL_INDEX;
             hash_index = client_info->used_next) {
                client_info = &(bond_info->rx_hashtbl[hash_index]);

                if ((client_info->slave == slave) &&
                    !ether_addr_equal_64bits(client_info->mac_dst, mac_bcast)) {
                        client_info->ntt = 1;
                        ntt = 1;
                }
        }

        /* update the team's flag only after the whole iteration */
        if (ntt) {
                bond_info->rx_ntt = 1;
                /* fasten the change */
                bond_info->rlb_update_retry_counter = RLB_UPDATE_RETRY;
        }

        _unlock_rx_hashtbl_bh(bond);
}

/* mark all clients using src_ip to be updated */
static void rlb_req_update_subnet_clients(struct bonding *bond, __be32 src_ip)
{
        struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond));
        struct rlb_client_info *client_info;
        u32 hash_index;

        _lock_rx_hashtbl(bond);

        hash_index = bond_info->rx_hashtbl_used_head;
        for (; hash_index != RLB_NULL_INDEX;
             hash_index = client_info->used_next) {
                client_info = &(bond_info->rx_hashtbl[hash_index]);

                if (!client_info->slave) {
                        pr_err("%s: Error: found a client with no channel in the client's hash table\n",
                               bond->dev->name);
                        continue;
                }
                /*update all clients using this src_ip, that are not assigned
                 * to the team's address (curr_active_slave) and have a known
                 * unicast mac address.
                 */
                if ((client_info->ip_src == src_ip) &&
                    !ether_addr_equal_64bits(client_info->slave->dev->dev_addr,
                                             bond->dev->dev_addr) &&
                    !ether_addr_equal_64bits(client_info->mac_dst, mac_bcast)) {
                        client_info->ntt = 1;
                        bond_info->rx_ntt = 1;
                }
        }

        _unlock_rx_hashtbl(bond);
}

/* Caller must hold both bond and ptr locks for read */
static struct slave *rlb_choose_channel(struct sk_buff *skb, struct bonding *bond)
{
        struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond));
        struct arp_pkt *arp = arp_pkt(skb);
        struct slave *assigned_slave, *curr_active_slave;
        struct rlb_client_info *client_info;
        u32 hash_index = 0;

        _lock_rx_hashtbl(bond);

        curr_active_slave = rcu_dereference(bond->curr_active_slave);

        hash_index = _simple_hash((u8 *)&arp->ip_dst, sizeof(arp->ip_dst));
        client_info = &(bond_info->rx_hashtbl[hash_index]);

        if (client_info->assigned) {
                if ((client_info->ip_src == arp->ip_src) &&
                    (client_info->ip_dst == arp->ip_dst)) {
                        /* the entry is already assigned to this client */
                        if (!ether_addr_equal_64bits(arp->mac_dst, mac_bcast)) {
                                /* update mac address from arp */
                                ether_addr_copy(client_info->mac_dst, arp->mac_dst);
                        }
                        ether_addr_copy(client_info->mac_src, arp->mac_src);

                        assigned_slave = client_info->slave;
                        if (assigned_slave) {
                                _unlock_rx_hashtbl(bond);
                                return assigned_slave;
                        }
                } else {
                        /* the entry is already assigned to some other client,
                         * move the old client to primary (curr_active_slave) so
                         * that the new client can be assigned to this entry.
                         */
                        if (bond->curr_active_slave &&
                            client_info->slave != curr_active_slave) {
                                client_info->slave = curr_active_slave;
                                rlb_update_client(client_info);
                        }
                }
        }
        /* assign a new slave */
        assigned_slave = __rlb_next_rx_slave(bond);

        if (assigned_slave) {
                if (!(client_info->assigned &&
                      client_info->ip_src == arp->ip_src)) {
                        /* ip_src is going to be updated,
                         * fix the src hash list
                         */
                        u32 hash_src = _simple_hash((u8 *)&arp->ip_src,
                                                    sizeof(arp->ip_src));
                        rlb_src_unlink(bond, hash_index);
                        rlb_src_link(bond, hash_src, hash_index);
                }

                client_info->ip_src = arp->ip_src;
                client_info->ip_dst = arp->ip_dst;
                /* arp->mac_dst is broadcast for arp reqeusts.
                 * will be updated with clients actual unicast mac address
                 * upon receiving an arp reply.
                 */
                ether_addr_copy(client_info->mac_dst, arp->mac_dst);
                ether_addr_copy(client_info->mac_src, arp->mac_src);
                client_info->slave = assigned_slave;

                if (!ether_addr_equal_64bits(client_info->mac_dst, mac_bcast)) {
                        client_info->ntt = 1;
                        bond->alb_info.rx_ntt = 1;
                } else {
                        client_info->ntt = 0;
                }

                if (vlan_get_tag(skb, &client_info->vlan_id))
                        client_info->vlan_id = 0;

                if (!client_info->assigned) {
                        u32 prev_tbl_head = bond_info->rx_hashtbl_used_head;
                        bond_info->rx_hashtbl_used_head = hash_index;
                        client_info->used_next = prev_tbl_head;
                        if (prev_tbl_head != RLB_NULL_INDEX) {
                                bond_info->rx_hashtbl[prev_tbl_head].used_prev =
                                        hash_index;
                        }
                        client_info->assigned = 1;
                }
        }

        _unlock_rx_hashtbl(bond);

        return assigned_slave;
}

/* chooses (and returns) transmit channel for arp reply
 * does not choose channel for other arp types since they are
 * sent on the curr_active_slave
 */
static struct slave *rlb_arp_xmit(struct sk_buff *skb, struct bonding *bond)
{
        struct arp_pkt *arp = arp_pkt(skb);
        struct slave *tx_slave = NULL;

        /* Don't modify or load balance ARPs that do not originate locally
         * (e.g.,arrive via a bridge).
         */
        if (!bond_slave_has_mac_rcu(bond, arp->mac_src))
                return NULL;

        if (arp->op_code == htons(ARPOP_REPLY)) {
                /* the arp must be sent on the selected
                * rx channel
                */
                tx_slave = rlb_choose_channel(skb, bond);
                if (tx_slave)
                        ether_addr_copy(arp->mac_src, tx_slave->dev->dev_addr);
                pr_debug("Server sent ARP Reply packet\n");
        } else if (arp->op_code == htons(ARPOP_REQUEST)) {
                /* Create an entry in the rx_hashtbl for this client as a
                 * place holder.
                 * When the arp reply is received the entry will be updated
                 * with the correct unicast address of the client.
                 */
                rlb_choose_channel(skb, bond);

                /* The ARP reply packets must be delayed so that
                 * they can cancel out the influence of the ARP request.
                 */
                bond->alb_info.rlb_update_delay_counter = RLB_UPDATE_DELAY;

                /* arp requests are broadcast and are sent on the primary
                 * the arp request will collapse all clients on the subnet to
                 * the primary slave. We must register these clients to be
                 * updated with their assigned mac.
                 */
                rlb_req_update_subnet_clients(bond, arp->ip_src);
                pr_debug("Server sent ARP Request packet\n");
        }

        return tx_slave;
}

/* Caller must hold bond lock for read */
static void rlb_rebalance(struct bonding *bond)
{
        struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond));
        struct slave *assigned_slave;
        struct rlb_client_info *client_info;
        int ntt;
        u32 hash_index;

        _lock_rx_hashtbl_bh(bond);

        ntt = 0;
        hash_index = bond_info->rx_hashtbl_used_head;
        for (; hash_index != RLB_NULL_INDEX;
             hash_index = client_info->used_next) {
                client_info = &(bond_info->rx_hashtbl[hash_index]);
                assigned_slave = __rlb_next_rx_slave(bond);
                if (assigned_slave && (client_info->slave != assigned_slave)) {
                        client_info->slave = assigned_slave;
                        client_info->ntt = 1;
                        ntt = 1;
                }
        }

        /* update the team's flag only after the whole iteration */
        if (ntt)
                bond_info->rx_ntt = 1;
        _unlock_rx_hashtbl_bh(bond);
}

/* Caller must hold rx_hashtbl lock */
static void rlb_init_table_entry_dst(struct rlb_client_info *entry)
{
        entry->used_next = RLB_NULL_INDEX;
        entry->used_prev = RLB_NULL_INDEX;
        entry->assigned = 0;
        entry->slave = NULL;
        entry->vlan_id = 0;
}
static void rlb_init_table_entry_src(struct rlb_client_info *entry)
{
        entry->src_first = RLB_NULL_INDEX;
        entry->src_prev = RLB_NULL_INDEX;
        entry->src_next = RLB_NULL_INDEX;
}

static void rlb_init_table_entry(struct rlb_client_info *entry)
{
        memset(entry, 0, sizeof(struct rlb_client_info));
        rlb_init_table_entry_dst(entry);
        rlb_init_table_entry_src(entry);
}

static void rlb_delete_table_entry_dst(struct bonding *bond, u32 index)
{
        struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond));
        u32 next_index = bond_info->rx_hashtbl[index].used_next;
        u32 prev_index = bond_info->rx_hashtbl[index].used_prev;

        if (index == bond_info->rx_hashtbl_used_head)
                bond_info->rx_hashtbl_used_head = next_index;
        if (prev_index != RLB_NULL_INDEX)
                bond_info->rx_hashtbl[prev_index].used_next = next_index;
        if (next_index != RLB_NULL_INDEX)
                bond_info->rx_hashtbl[next_index].used_prev = prev_index;
}

/* unlink a rlb hash table entry from the src list */
static void rlb_src_unlink(struct bonding *bond, u32 index)
{
        struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond));
        u32 next_index = bond_info->rx_hashtbl[index].src_next;
        u32 prev_index = bond_info->rx_hashtbl[index].src_prev;

        bond_info->rx_hashtbl[index].src_next = RLB_NULL_INDEX;
        bond_info->rx_hashtbl[index].src_prev = RLB_NULL_INDEX;

        if (next_index != RLB_NULL_INDEX)
                bond_info->rx_hashtbl[next_index].src_prev = prev_index;

        if (prev_index == RLB_NULL_INDEX)
                return;

        /* is prev_index pointing to the head of this list? */
        if (bond_info->rx_hashtbl[prev_index].src_first == index)
                bond_info->rx_hashtbl[prev_index].src_first = next_index;
        else
                bond_info->rx_hashtbl[prev_index].src_next = next_index;

}

static void rlb_delete_table_entry(struct bonding *bond, u32 index)
{
        struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond));
        struct rlb_client_info *entry = &(bond_info->rx_hashtbl[index]);

        rlb_delete_table_entry_dst(bond, index);
        rlb_init_table_entry_dst(entry);

        rlb_src_unlink(bond, index);
}

/* add the rx_hashtbl[ip_dst_hash] entry to the list
 * of entries with identical ip_src_hash
 */
static void rlb_src_link(struct bonding *bond, u32 ip_src_hash, u32 ip_dst_hash)
{
        struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond));
        u32 next;

        bond_info->rx_hashtbl[ip_dst_hash].src_prev = ip_src_hash;
        next = bond_info->rx_hashtbl[ip_src_hash].src_first;
        bond_info->rx_hashtbl[ip_dst_hash].src_next = next;
        if (next != RLB_NULL_INDEX)
                bond_info->rx_hashtbl[next].src_prev = ip_dst_hash;
        bond_info->rx_hashtbl[ip_src_hash].src_first = ip_dst_hash;
}

/* deletes all rx_hashtbl entries with  arp->ip_src if their mac_src does
 * not match arp->mac_src */
static void rlb_purge_src_ip(struct bonding *bond, struct arp_pkt *arp)
{
        struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond));
        u32 ip_src_hash = _simple_hash((u8 *)&(arp->ip_src), sizeof(arp->ip_src));
        u32 index;

        _lock_rx_hashtbl_bh(bond);

        index = bond_info->rx_hashtbl[ip_src_hash].src_first;
        while (index != RLB_NULL_INDEX) {
                struct rlb_client_info *entry = &(bond_info->rx_hashtbl[index]);
                u32 next_index = entry->src_next;
                if (entry->ip_src == arp->ip_src &&
                    !ether_addr_equal_64bits(arp->mac_src, entry->mac_src))
                                rlb_delete_table_entry(bond, index);
                index = next_index;
        }
        _unlock_rx_hashtbl_bh(bond);
}

static int rlb_initialize(struct bonding *bond)
{
        struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond));
        struct rlb_client_info  *new_hashtbl;
        int size = RLB_HASH_TABLE_SIZE * sizeof(struct rlb_client_info);
        int i;

        new_hashtbl = kmalloc(size, GFP_KERNEL);
        if (!new_hashtbl)
                return -1;

        _lock_rx_hashtbl_bh(bond);

        bond_info->rx_hashtbl = new_hashtbl;

        bond_info->rx_hashtbl_used_head = RLB_NULL_INDEX;

        for (i = 0; i < RLB_HASH_TABLE_SIZE; i++)
                rlb_init_table_entry(bond_info->rx_hashtbl + i);

        _unlock_rx_hashtbl_bh(bond);

        /* register to receive ARPs */
        bond->recv_probe = rlb_arp_recv;

        return 0;
}

static void rlb_deinitialize(struct bonding *bond)
{
        struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond));

        _lock_rx_hashtbl_bh(bond);

        kfree(bond_info->rx_hashtbl);
        bond_info->rx_hashtbl = NULL;
        bond_info->rx_hashtbl_used_head = RLB_NULL_INDEX;

        _unlock_rx_hashtbl_bh(bond);
}

static void rlb_clear_vlan(struct bonding *bond, unsigned short vlan_id)
{
        struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond));
        u32 curr_index;

        _lock_rx_hashtbl_bh(bond);

        curr_index = bond_info->rx_hashtbl_used_head;
        while (curr_index != RLB_NULL_INDEX) {
                struct rlb_client_info *curr = &(bond_info->rx_hashtbl[curr_index]);
                u32 next_index = bond_info->rx_hashtbl[curr_index].used_next;

                if (curr->vlan_id == vlan_id)
                        rlb_delete_table_entry(bond, curr_index);

                curr_index = next_index;
        }

        _unlock_rx_hashtbl_bh(bond);
}

/*********************** tlb/rlb shared functions *********************/

static void alb_send_lp_vid(struct slave *slave, u8 mac_addr[],
                            u16 vid)
{
        struct learning_pkt pkt;
        struct sk_buff *skb;
        int size = sizeof(struct learning_pkt);
        char *data;

        memset(&pkt, 0, size);
        ether_addr_copy(pkt.mac_dst, mac_addr);
        ether_addr_copy(pkt.mac_src, mac_addr);
        pkt.type = cpu_to_be16(ETH_P_LOOPBACK);

        skb = dev_alloc_skb(size);
        if (!skb)
                return;

        data = skb_put(skb, size);
        memcpy(data, &pkt, size);

        skb_reset_mac_header(skb);
        skb->network_header = skb->mac_header + ETH_HLEN;
        skb->protocol = pkt.type;
        skb->priority = TC_PRIO_CONTROL;
        skb->dev = slave->dev;

        if (vid) {
                skb = vlan_put_tag(skb, htons(ETH_P_8021Q), vid);
                if (!skb) {
                        pr_err("%s: Error: failed to insert VLAN tag\n",
                               slave->bond->dev->name);
                        return;
                }
        }

        dev_queue_xmit(skb);
}


static void alb_send_learning_packets(struct slave *slave, u8 mac_addr[])
{
        struct bonding *bond = bond_get_bond_by_slave(slave);
        struct net_device *upper;
        struct list_head *iter;

        /* send untagged */
        alb_send_lp_vid(slave, mac_addr, 0);

        /* loop through vlans and send one packet for each */
        rcu_read_lock();
        netdev_for_each_all_upper_dev_rcu(bond->dev, upper, iter) {
                if (upper->priv_flags & IFF_802_1Q_VLAN)
                        alb_send_lp_vid(slave, mac_addr,
                                        vlan_dev_vlan_id(upper));
        }
        rcu_read_unlock();
}

static int alb_set_slave_mac_addr(struct slave *slave, u8 addr[])
{
        struct net_device *dev = slave->dev;
        struct sockaddr s_addr;

        if (slave->bond->params.mode == BOND_MODE_TLB) {
                memcpy(dev->dev_addr, addr, dev->addr_len);
                return 0;
        }

        /* for rlb each slave must have a unique hw mac addresses so that */
        /* each slave will receive packets destined to a different mac */
        memcpy(s_addr.sa_data, addr, dev->addr_len);
        s_addr.sa_family = dev->type;
        if (dev_set_mac_address(dev, &s_addr)) {
                pr_err("%s: Error: dev_set_mac_address of dev %s failed!\n"
                       "ALB mode requires that the base driver support setting the hw address also when the network device's interface is open\n",
                       slave->bond->dev->name, dev->name);
                return -EOPNOTSUPP;
        }
        return 0;
}

/*
 * Swap MAC addresses between two slaves.
 *
 * Called with RTNL held, and no other locks.
 *
 */

static void alb_swap_mac_addr(struct slave *slave1, struct slave *slave2)
{
        u8 tmp_mac_addr[ETH_ALEN];

        ether_addr_copy(tmp_mac_addr, slave1->dev->dev_addr);
        alb_set_slave_mac_addr(slave1, slave2->dev->dev_addr);
        alb_set_slave_mac_addr(slave2, tmp_mac_addr);

}

/*
 * Send learning packets after MAC address swap.
 *
 * Called with RTNL and no other locks
 */
static void alb_fasten_mac_swap(struct bonding *bond, struct slave *slave1,
                                struct slave *slave2)
{
        int slaves_state_differ = (SLAVE_IS_OK(slave1) != SLAVE_IS_OK(slave2));
        struct slave *disabled_slave = NULL;

        ASSERT_RTNL();

        /* fasten the change in the switch */
        if (SLAVE_IS_OK(slave1)) {
                alb_send_learning_packets(slave1, slave1->dev->dev_addr);
                if (bond->alb_info.rlb_enabled) {
                        /* inform the clients that the mac address
                         * has changed
                         */
                        rlb_req_update_slave_clients(bond, slave1);
                }
        } else {
                disabled_slave = slave1;
        }

        if (SLAVE_IS_OK(slave2)) {
                alb_send_learning_packets(slave2, slave2->dev->dev_addr);
                if (bond->alb_info.rlb_enabled) {
                        /* inform the clients that the mac address
                         * has changed
                         */
                        rlb_req_update_slave_clients(bond, slave2);
                }
        } else {
                disabled_slave = slave2;
        }

        if (bond->alb_info.rlb_enabled && slaves_state_differ) {
                /* A disabled slave was assigned an active mac addr */
                rlb_teach_disabled_mac_on_primary(bond,
                                                  disabled_slave->dev->dev_addr);
        }
}

/**
 * alb_change_hw_addr_on_detach
 * @bond: bonding we're working on
 * @slave: the slave that was just detached
 *
 * We assume that @slave was already detached from the slave list.
 *
 * If @slave's permanent hw address is different both from its current
 * address and from @bond's address, then somewhere in the bond there's
 * a slave that has @slave's permanet address as its current address.
 * We'll make sure that that slave no longer uses @slave's permanent address.
 *
 * Caller must hold RTNL and no other locks
 */
static void alb_change_hw_addr_on_detach(struct bonding *bond, struct slave *slave)
{
        int perm_curr_diff;
        int perm_bond_diff;
        struct slave *found_slave;

        perm_curr_diff = !ether_addr_equal_64bits(slave->perm_hwaddr,
                                                  slave->dev->dev_addr);
        perm_bond_diff = !ether_addr_equal_64bits(slave->perm_hwaddr,
                                                  bond->dev->dev_addr);

        if (perm_curr_diff && perm_bond_diff) {
                found_slave = bond_slave_has_mac(bond, slave->perm_hwaddr);

                if (found_slave) {
                        /* locking: needs RTNL and nothing else */
                        alb_swap_mac_addr(slave, found_slave);
                        alb_fasten_mac_swap(bond, slave, found_slave);
                }
        }
}

/**
 * alb_handle_addr_collision_on_attach
 * @bond: bonding we're working on
 * @slave: the slave that was just attached
 *
 * checks uniqueness of slave's mac address and handles the case the
 * new slave uses the bonds mac address.
 *
 * If the permanent hw address of @slave is @bond's hw address, we need to
 * find a different hw address to give @slave, that isn't in use by any other
 * slave in the bond. This address must be, of course, one of the permanent
 * addresses of the other slaves.
 *
 * We go over the slave list, and for each slave there we compare its
 * permanent hw address with the current address of all the other slaves.
 * If no match was found, then we've found a slave with a permanent address
 * that isn't used by any other slave in the bond, so we can assign it to
 * @slave.
 *
 * assumption: this function is called before @slave is attached to the
 *             bond slave list.
 */
static int alb_handle_addr_collision_on_attach(struct bonding *bond, struct slave *slave)
{
        struct slave *has_bond_addr = bond->curr_active_slave;
        struct slave *tmp_slave1, *free_mac_slave = NULL;
        struct list_head *iter;

        if (!bond_has_slaves(bond)) {
                /* this is the first slave */
                return 0;
        }

        /* if slave's mac address differs from bond's mac address
         * check uniqueness of slave's mac address against the other
         * slaves in the bond.
         */
        if (!ether_addr_equal_64bits(slave->perm_hwaddr, bond->dev->dev_addr)) {
                if (!bond_slave_has_mac(bond, slave->dev->dev_addr))
                        return 0;

                /* Try setting slave mac to bond address and fall-through
                   to code handling that situation below... */
                alb_set_slave_mac_addr(slave, bond->dev->dev_addr);
        }

        /* The slave's address is equal to the address of the bond.
         * Search for a spare address in the bond for this slave.
         */
        bond_for_each_slave(bond, tmp_slave1, iter) {
                if (!bond_slave_has_mac(bond, tmp_slave1->perm_hwaddr)) {
                        /* no slave has tmp_slave1's perm addr
                         * as its curr addr
                         */
                        free_mac_slave = tmp_slave1;
                        break;
                }

                if (!has_bond_addr) {
                        if (ether_addr_equal_64bits(tmp_slave1->dev->dev_addr,
                                                    bond->dev->dev_addr)) {

                                has_bond_addr = tmp_slave1;
                        }
                }
        }

        if (free_mac_slave) {
                alb_set_slave_mac_addr(slave, free_mac_slave->perm_hwaddr);

                pr_warn("%s: Warning: the hw address of slave %s is in use by the bond; giving it the hw address of %s\n",
                        bond->dev->name, slave->dev->name,
                        free_mac_slave->dev->name);

        } else if (has_bond_addr) {
                pr_err("%s: Error: the hw address of slave %s is in use by the bond; couldn't find a slave with a free hw address to give it (this should not have happened)\n",
                       bond->dev->name, slave->dev->name);
                return -EFAULT;
        }

        return 0;
}

/**
 * alb_set_mac_address
 * @bond:
 * @addr:
 *
 * In TLB mode all slaves are configured to the bond's hw address, but set
 * their dev_addr field to different addresses (based on their permanent hw
 * addresses).
 *
 * For each slave, this function sets the interface to the new address and then
 * changes its dev_addr field to its previous value.
 *
 * Unwinding assumes bond's mac address has not yet changed.
 */
static int alb_set_mac_address(struct bonding *bond, void *addr)
{
        struct slave *slave, *rollback_slave;
        struct list_head *iter;
        struct sockaddr sa;
        char tmp_addr[ETH_ALEN];
        int res;

        if (bond->alb_info.rlb_enabled)
                return 0;

        bond_for_each_slave(bond, slave, iter) {
                /* save net_device's current hw address */
                ether_addr_copy(tmp_addr, slave->dev->dev_addr);

                res = dev_set_mac_address(slave->dev, addr);

                /* restore net_device's hw address */
                ether_addr_copy(slave->dev->dev_addr, tmp_addr);

                if (res)
                        goto unwind;
        }

        return 0;

unwind:
        memcpy(sa.sa_data, bond->dev->dev_addr, bond->dev->addr_len);
        sa.sa_family = bond->dev->type;

        /* unwind from head to the slave that failed */
        bond_for_each_slave(bond, rollback_slave, iter) {
                if (rollback_slave == slave)
                        break;
                ether_addr_copy(tmp_addr, rollback_slave->dev->dev_addr);
                dev_set_mac_address(rollback_slave->dev, &sa);
                ether_addr_copy(rollback_slave->dev->dev_addr, tmp_addr);
        }

        return res;
}

/************************ exported alb funcions ************************/

int bond_alb_initialize(struct bonding *bond, int rlb_enabled)
{
        int res;

        res = tlb_initialize(bond);
        if (res)
                return res;

        if (rlb_enabled) {
                bond->alb_info.rlb_enabled = 1;
                /* initialize rlb */
                res = rlb_initialize(bond);
                if (res) {
                        tlb_deinitialize(bond);
                        return res;
                }
        } else {
                bond->alb_info.rlb_enabled = 0;
        }

        return 0;
}

void bond_alb_deinitialize(struct bonding *bond)
{
        struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond));

        tlb_deinitialize(bond);

        if (bond_info->rlb_enabled)
                rlb_deinitialize(bond);
}

int bond_alb_xmit(struct sk_buff *skb, struct net_device *bond_dev)
{
        struct bonding *bond = netdev_priv(bond_dev);
        struct ethhdr *eth_data;
        struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond));
        struct slave *tx_slave = NULL;
        static const __be32 ip_bcast = htonl(0xffffffff);
        int hash_size = 0;
        int do_tx_balance = 1;
        u32 hash_index = 0;
        const u8 *hash_start = NULL;
        struct ipv6hdr *ip6hdr;

        skb_reset_mac_header(skb);
        eth_data = eth_hdr(skb);

        switch (ntohs(skb->protocol)) {
        case ETH_P_IP: {
                const struct iphdr *iph = ip_hdr(skb);

                if (ether_addr_equal_64bits(eth_data->h_dest, mac_bcast) ||
                    (iph->daddr == ip_bcast) ||
                    (iph->protocol == IPPROTO_IGMP)) {
                        do_tx_balance = 0;
                        break;
                }
                hash_start = (char *)&(iph->daddr);
                hash_size = sizeof(iph->daddr);
        }
                break;
        case ETH_P_IPV6:
                /* IPv6 doesn't really use broadcast mac address, but leave
                 * that here just in case.
                 */
                if (ether_addr_equal_64bits(eth_data->h_dest, mac_bcast)) {
                        do_tx_balance = 0;
                        break;
                }

                /* IPv6 uses all-nodes multicast as an equivalent to
                 * broadcasts in IPv4.
                 */
                if (ether_addr_equal_64bits(eth_data->h_dest, mac_v6_allmcast)) {
                        do_tx_balance = 0;
                        break;
                }

                /* Additianally, DAD probes should not be tx-balanced as that
                 * will lead to false positives for duplicate addresses and
                 * prevent address configuration from working.
                 */
                ip6hdr = ipv6_hdr(skb);
                if (ipv6_addr_any(&ip6hdr->saddr)) {
                        do_tx_balance = 0;
                        break;
                }

                hash_start = (char *)&(ipv6_hdr(skb)->daddr);
                hash_size = sizeof(ipv6_hdr(skb)->daddr);
                break;
        case ETH_P_IPX:
                if (ipx_hdr(skb)->ipx_checksum != IPX_NO_CHECKSUM) {
                        /* something is wrong with this packet */
                        do_tx_balance = 0;
                        break;
                }

                if (ipx_hdr(skb)->ipx_type != IPX_TYPE_NCP) {
                        /* The only protocol worth balancing in
                         * this family since it has an "ARP" like
                         * mechanism
                         */
                        do_tx_balance = 0;
                        break;
                }

                hash_start = (char *)eth_data->h_dest;
                hash_size = ETH_ALEN;
                break;
        case ETH_P_ARP:
                do_tx_balance = 0;
                if (bond_info->rlb_enabled)
                        tx_slave = rlb_arp_xmit(skb, bond);
                break;
        default:
                do_tx_balance = 0;
                break;
        }

        if (do_tx_balance) {
                hash_index = _simple_hash(hash_start, hash_size);
                tx_slave = tlb_choose_channel(bond, hash_index, skb->len);
        }

        if (!tx_slave) {
                /* unbalanced or unassigned, send through primary */
                tx_slave = rcu_dereference(bond->curr_active_slave);
                bond_info->unbalanced_load += skb->len;
        }

        if (tx_slave && SLAVE_IS_OK(tx_slave)) {
                if (tx_slave != rcu_dereference(bond->curr_active_slave)) {
                        ether_addr_copy(eth_data->h_source,
                                        tx_slave->dev->dev_addr);
                }

                bond_dev_queue_xmit(bond, skb, tx_slave->dev);
                goto out;
        }

        if (tx_slave) {
                _lock_tx_hashtbl(bond);
                __tlb_clear_slave(bond, tx_slave, 0);
                _unlock_tx_hashtbl(bond);
        }

        /* no suitable interface, frame not sent */
        dev_kfree_skb_any(skb);
out:
        return NETDEV_TX_OK;
}

void bond_alb_monitor(struct work_struct *work)
{
        struct bonding *bond = container_of(work, struct bonding,
                                            alb_work.work);
        struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond));
        struct list_head *iter;
        struct slave *slave;

        if (!bond_has_slaves(bond)) {
                bond_info->tx_rebalance_counter = 0;
                bond_info->lp_counter = 0;
                goto re_arm;
        }

        rcu_read_lock();

        bond_info->tx_rebalance_counter++;
        bond_info->lp_counter++;

        /* send learning packets */
        if (bond_info->lp_counter >= BOND_ALB_LP_TICKS(bond)) {
                /* change of curr_active_slave involves swapping of mac addresses.
                 * in order to avoid this swapping from happening while
                 * sending the learning packets, the curr_slave_lock must be held for
                 * read.
                 */
                read_lock(&bond->curr_slave_lock);

                bond_for_each_slave_rcu(bond, slave, iter)
                        alb_send_learning_packets(slave, slave->dev->dev_addr);

                read_unlock(&bond->curr_slave_lock);

                bond_info->lp_counter = 0;
        }

        /* rebalance tx traffic */
        if (bond_info->tx_rebalance_counter >= BOND_TLB_REBALANCE_TICKS) {

                read_lock(&bond->curr_slave_lock);

                bond_for_each_slave_rcu(bond, slave, iter) {
                        tlb_clear_slave(bond, slave, 1);
                        if (slave == bond->curr_active_slave) {
                                SLAVE_TLB_INFO(slave).load =
                                        bond_info->unbalanced_load /
                                                BOND_TLB_REBALANCE_INTERVAL;
                                bond_info->unbalanced_load = 0;
                        }
                }

                read_unlock(&bond->curr_slave_lock);

                bond_info->tx_rebalance_counter = 0;
        }

        /* handle rlb stuff */
        if (bond_info->rlb_enabled) {
                if (bond_info->primary_is_promisc &&
                    (++bond_info->rlb_promisc_timeout_counter >= RLB_PROMISC_TIMEOUT)) {

                        /*
                         * dev_set_promiscuity requires rtnl and
                         * nothing else.  Avoid race with bond_close.
                         */
                        rcu_read_unlock();
                        if (!rtnl_trylock())
                                goto re_arm;

                        bond_info->rlb_promisc_timeout_counter = 0;

                        /* If the primary was set to promiscuous mode
                         * because a slave was disabled then
                         * it can now leave promiscuous mode.
                         */
                        dev_set_promiscuity(bond->curr_active_slave->dev, -1);
                        bond_info->primary_is_promisc = 0;

                        rtnl_unlock();
                        rcu_read_lock();
                }

                if (bond_info->rlb_rebalance) {
                        bond_info->rlb_rebalance = 0;
                        rlb_rebalance(bond);
                }

                /* check if clients need updating */
                if (bond_info->rx_ntt) {
                        if (bond_info->rlb_update_delay_counter) {
                                --bond_info->rlb_update_delay_counter;
                        } else {
                                rlb_update_rx_clients(bond);
                                if (bond_info->rlb_update_retry_counter)
                                        --bond_info->rlb_update_retry_counter;
                                else
                                        bond_info->rx_ntt = 0;
                        }
                }
        }
        rcu_read_unlock();
re_arm:
        queue_delayed_work(bond->wq, &bond->alb_work, alb_delta_in_ticks);
}

/* assumption: called before the slave is attached to the bond
 * and not locked by the bond lock
 */
int bond_alb_init_slave(struct bonding *bond, struct slave *slave)
{
        int res;

        res = alb_set_slave_mac_addr(slave, slave->perm_hwaddr);
        if (res)
                return res;

        res = alb_handle_addr_collision_on_attach(bond, slave);
        if (res)
                return res;

        tlb_init_slave(slave);

        /* order a rebalance ASAP */
        bond->alb_info.tx_rebalance_counter = BOND_TLB_REBALANCE_TICKS;

        if (bond->alb_info.rlb_enabled)
                bond->alb_info.rlb_rebalance = 1;

        return 0;
}

/*
 * Remove slave from tlb and rlb hash tables, and fix up MAC addresses
 * if necessary.
 *
 * Caller must hold RTNL and no other locks
 */
void bond_alb_deinit_slave(struct bonding *bond, struct slave *slave)
{
        if (bond_has_slaves(bond))
                alb_change_hw_addr_on_detach(bond, slave);

        tlb_clear_slave(bond, slave, 0);

        if (bond->alb_info.rlb_enabled) {
                bond->alb_info.rx_slave = NULL;
                rlb_clear_slave(bond, slave);
        }
}

/* Caller must hold bond lock for read */
void bond_alb_handle_link_change(struct bonding *bond, struct slave *slave, char link)
{
        struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond));

        if (link == BOND_LINK_DOWN) {
                tlb_clear_slave(bond, slave, 0);
                if (bond->alb_info.rlb_enabled)
                        rlb_clear_slave(bond, slave);
        } else if (link == BOND_LINK_UP) {
                /* order a rebalance ASAP */
                bond_info->tx_rebalance_counter = BOND_TLB_REBALANCE_TICKS;
                if (bond->alb_info.rlb_enabled) {
                        bond->alb_info.rlb_rebalance = 1;
                        /* If the updelay module parameter is smaller than the
                         * forwarding delay of the switch the rebalance will
                         * not work because the rebalance arp replies will
                         * not be forwarded to the clients..
                         */
                }
        }
}

/**
 * bond_alb_handle_active_change - assign new curr_active_slave
 * @bond: our bonding struct
 * @new_slave: new slave to assign
 *
 * Set the bond->curr_active_slave to @new_slave and handle
 * mac address swapping and promiscuity changes as needed.
 *
 * If new_slave is NULL, caller must hold curr_slave_lock or
 * bond->lock for write.
 *
 * If new_slave is not NULL, caller must hold RTNL, curr_slave_lock
 * for write.  Processing here may sleep, so no other locks may be held.
 */
void bond_alb_handle_active_change(struct bonding *bond, struct slave *new_slave)
        __releases(&bond->curr_slave_lock)
        __acquires(&bond->curr_slave_lock)
{
        struct slave *swap_slave;

        if (bond->curr_active_slave == new_slave)
                return;

        if (bond->curr_active_slave && bond->alb_info.primary_is_promisc) {
                dev_set_promiscuity(bond->curr_active_slave->dev, -1);
                bond->alb_info.primary_is_promisc = 0;
                bond->alb_info.rlb_promisc_timeout_counter = 0;
        }

        swap_slave = bond->curr_active_slave;
        rcu_assign_pointer(bond->curr_active_slave, new_slave);

        if (!new_slave || !bond_has_slaves(bond))
                return;

        /* set the new curr_active_slave to the bonds mac address
         * i.e. swap mac addresses of old curr_active_slave and new curr_active_slave
         */
        if (!swap_slave)
                swap_slave = bond_slave_has_mac(bond, bond->dev->dev_addr);

        /*
         * Arrange for swap_slave and new_slave to temporarily be
         * ignored so we can mess with their MAC addresses without
         * fear of interference from transmit activity.
         */
        if (swap_slave)
                tlb_clear_slave(bond, swap_slave, 1);
        tlb_clear_slave(bond, new_slave, 1);

        write_unlock_bh(&bond->curr_slave_lock);

        ASSERT_RTNL();

        /* in TLB mode, the slave might flip down/up with the old dev_addr,
         * and thus filter bond->dev_addr's packets, so force bond's mac
         */
        if (bond->params.mode == BOND_MODE_TLB) {
                struct sockaddr sa;
                u8 tmp_addr[ETH_ALEN];

                ether_addr_copy(tmp_addr, new_slave->dev->dev_addr);

                memcpy(sa.sa_data, bond->dev->dev_addr, bond->dev->addr_len);
                sa.sa_family = bond->dev->type;
                /* we don't care if it can't change its mac, best effort */
                dev_set_mac_address(new_slave->dev, &sa);

                ether_addr_copy(new_slave->dev->dev_addr, tmp_addr);
        }

        /* curr_active_slave must be set before calling alb_swap_mac_addr */
        if (swap_slave) {
                /* swap mac address */
                alb_swap_mac_addr(swap_slave, new_slave);
                alb_fasten_mac_swap(bond, swap_slave, new_slave);
        } else {
                /* set the new_slave to the bond mac address */
                alb_set_slave_mac_addr(new_slave, bond->dev->dev_addr);
                alb_send_learning_packets(new_slave, bond->dev->dev_addr);
        }

        write_lock_bh(&bond->curr_slave_lock);
}

/*
 * Called with RTNL
 */
int bond_alb_set_mac_address(struct net_device *bond_dev, void *addr)
        __acquires(&bond->lock)
        __releases(&bond->lock)
{
        struct bonding *bond = netdev_priv(bond_dev);
        struct sockaddr *sa = addr;
        struct slave *swap_slave;
        int res;

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

        res = alb_set_mac_address(bond, addr);
        if (res)
                return res;

        memcpy(bond_dev->dev_addr, sa->sa_data, bond_dev->addr_len);

        /* If there is no curr_active_slave there is nothing else to do.
         * Otherwise we'll need to pass the new address to it and handle
         * duplications.
         */
        if (!bond->curr_active_slave)
                return 0;

        swap_slave = bond_slave_has_mac(bond, bond_dev->dev_addr);

        if (swap_slave) {
                alb_swap_mac_addr(swap_slave, bond->curr_active_slave);
                alb_fasten_mac_swap(bond, swap_slave, bond->curr_active_slave);
        } else {
                alb_set_slave_mac_addr(bond->curr_active_slave, bond_dev->dev_addr);

                read_lock(&bond->lock);
                alb_send_learning_packets(bond->curr_active_slave, bond_dev->dev_addr);
                if (bond->alb_info.rlb_enabled) {
                        /* inform clients mac address has changed */
                        rlb_req_update_slave_clients(bond, bond->curr_active_slave);
                }
                read_unlock(&bond->lock);
        }

        return 0;
}

void bond_alb_clear_vlan(struct bonding *bond, unsigned short vlan_id)
{
        if (bond->alb_info.rlb_enabled)
                rlb_clear_vlan(bond, vlan_id);
}