Merge /spare/repo/linux-2.6/

[linux-2.6] / drivers / net / bonding / 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.
 *
 * v0.1 - first working version.
 * v0.2 - changed stats to be calculated by summing slaves stats.
 *
 * Changes:
 * Arnaldo Carvalho de Melo <acme@conectiva.com.br>
 * - fix leaks on failure at bond_init
 *
 * 2000/09/30 - Willy Tarreau <willy at meta-x.org>
 *     - added trivial code to release a slave device.
 *     - fixed security bug (CAP_NET_ADMIN not checked)
 *     - implemented MII link monitoring to disable dead links :
 *       All MII capable slaves are checked every <miimon> milliseconds
 *       (100 ms seems good). This value can be changed by passing it to
 *       insmod. A value of zero disables the monitoring (default).
 *     - fixed an infinite loop in bond_xmit_roundrobin() when there's no
 *       good slave.
 *     - made the code hopefully SMP safe
 *
 * 2000/10/03 - Willy Tarreau <willy at meta-x.org>
 *     - optimized slave lists based on relevant suggestions from Thomas Davis
 *     - implemented active-backup method to obtain HA with two switches:
 *       stay as long as possible on the same active interface, while we
 *       also monitor the backup one (MII link status) because we want to know
 *       if we are able to switch at any time. ( pass "mode=1" to insmod )
 *     - lots of stress testings because we need it to be more robust than the
 *       wires ! :->
 *
 * 2000/10/09 - Willy Tarreau <willy at meta-x.org>
 *     - added up and down delays after link state change.
 *     - optimized the slaves chaining so that when we run forward, we never
 *       repass through the bond itself, but we can find it by searching
 *       backwards. Renders the deletion more difficult, but accelerates the
 *       scan.
 *     - smarter enslaving and releasing.
 *     - finer and more robust SMP locking
 *
 * 2000/10/17 - Willy Tarreau <willy at meta-x.org>
 *     - fixed two potential SMP race conditions
 *
 * 2000/10/18 - Willy Tarreau <willy at meta-x.org>
 *     - small fixes to the monitoring FSM in case of zero delays
 * 2000/11/01 - Willy Tarreau <willy at meta-x.org>
 *     - fixed first slave not automatically used in trunk mode.
 * 2000/11/10 : spelling of "EtherChannel" corrected.
 * 2000/11/13 : fixed a race condition in case of concurrent accesses to ioctl().
 * 2000/12/16 : fixed improper usage of rtnl_exlock_nowait().
 *
 * 2001/1/3 - Chad N. Tindel <ctindel at ieee dot org>
 *     - The bonding driver now simulates MII status monitoring, just like
 *       a normal network device.  It will show that the link is down iff
 *       every slave in the bond shows that their links are down.  If at least
 *       one slave is up, the bond's MII status will appear as up.
 *
 * 2001/2/7 - Chad N. Tindel <ctindel at ieee dot org>
 *     - Applications can now query the bond from user space to get
 *       information which may be useful.  They do this by calling
 *       the BOND_INFO_QUERY ioctl.  Once the app knows how many slaves
 *       are in the bond, it can call the BOND_SLAVE_INFO_QUERY ioctl to
 *       get slave specific information (# link failures, etc).  See
 *       <linux/if_bonding.h> for more details.  The structs of interest
 *       are ifbond and ifslave.
 *
 * 2001/4/5 - Chad N. Tindel <ctindel at ieee dot org>
 *     - Ported to 2.4 Kernel
 *
 * 2001/5/2 - Jeffrey E. Mast <jeff at mastfamily dot com>
 *     - When a device is detached from a bond, the slave device is no longer
 *       left thinking that is has a master.
 *
 * 2001/5/16 - Jeffrey E. Mast <jeff at mastfamily dot com>
 *     - memset did not appropriately initialized the bond rw_locks. Used
 *       rwlock_init to initialize to unlocked state to prevent deadlock when
 *       first attempting a lock
 *     - Called SET_MODULE_OWNER for bond device
 *
 * 2001/5/17 - Tim Anderson <tsa at mvista.com>
 *     - 2 paths for releasing for slave release; 1 through ioctl
 *       and 2) through close. Both paths need to release the same way.
 *     - the free slave in bond release is changing slave status before
 *       the free. The netdev_set_master() is intended to change slave state
 *       so it should not be done as part of the release process.
 *     - Simple rule for slave state at release: only the active in A/B and
 *       only one in the trunked case.
 *
 * 2001/6/01 - Tim Anderson <tsa at mvista.com>
 *     - Now call dev_close when releasing a slave so it doesn't screw up
 *       out routing table.
 *
 * 2001/6/01 - Chad N. Tindel <ctindel at ieee dot org>
 *     - Added /proc support for getting bond and slave information.
 *       Information is in /proc/net/<bond device>/info.
 *     - Changed the locking when calling bond_close to prevent deadlock.
 *
 * 2001/8/05 - Janice Girouard <girouard at us.ibm.com>
 *     - correct problem where refcnt of slave is not incremented in bond_ioctl
 *       so the system hangs when halting.
 *     - correct locking problem when unable to malloc in bond_enslave.
 *     - adding bond_xmit_xor logic.
 *     - adding multiple bond device support.
 *
 * 2001/8/13 - Erik Habbinga <erik_habbinga at hp dot com>
 *     - correct locking problem with rtnl_exlock_nowait
 *
 * 2001/8/23 - Janice Girouard <girouard at us.ibm.com>
 *     - bzero initial dev_bonds, to correct oops
 *     - convert SIOCDEVPRIVATE to new MII ioctl calls
 *
 * 2001/9/13 - Takao Indoh <indou dot takao at jp dot fujitsu dot com>
 *     - Add the BOND_CHANGE_ACTIVE ioctl implementation
 *
 * 2001/9/14 - Mark Huth <mhuth at mvista dot com>
 *     - Change MII_LINK_READY to not check for end of auto-negotiation,
 *       but only for an up link.
 *
 * 2001/9/20 - Chad N. Tindel <ctindel at ieee dot org>
 *     - Add the device field to bonding_t.  Previously the net_device
 *       corresponding to a bond wasn't available from the bonding_t
 *       structure.
 *
 * 2001/9/25 - Janice Girouard <girouard at us.ibm.com>
 *     - add arp_monitor for active backup mode
 *
 * 2001/10/23 - Takao Indoh <indou dot takao at jp dot fujitsu dot com>
 *     - Various memory leak fixes
 *
 * 2001/11/5 - Mark Huth <mark dot huth at mvista dot com>
 *     - Don't take rtnl lock in bond_mii_monitor as it deadlocks under
 *       certain hotswap conditions.
 *       Note:  this same change may be required in bond_arp_monitor ???
 *     - Remove possibility of calling bond_sethwaddr with NULL slave_dev ptr
 *     - Handle hot swap ethernet interface deregistration events to remove
 *       kernel oops following hot swap of enslaved interface
 *
 * 2002/1/2 - Chad N. Tindel <ctindel at ieee dot org>
 *     - Restore original slave flags at release time.
 *
 * 2002/02/18 - Erik Habbinga <erik_habbinga at hp dot com>
 *     - bond_release(): calling kfree on our_slave after call to
 *       bond_restore_slave_flags, not before
 *     - bond_enslave(): saving slave flags into original_flags before
 *       call to netdev_set_master, so the IFF_SLAVE flag doesn't end
 *       up in original_flags
 *
 * 2002/04/05 - Mark Smith <mark.smith at comdev dot cc> and
 *              Steve Mead <steve.mead at comdev dot cc>
 *     - Port Gleb Natapov's multicast support patchs from 2.4.12
 *       to 2.4.18 adding support for multicast.
 *
 * 2002/06/10 - Tony Cureington <tony.cureington * hp_com>
 *     - corrected uninitialized pointer (ifr.ifr_data) in bond_check_dev_link;
 *       actually changed function to use MIIPHY, then MIIREG, and finally
 *       ETHTOOL to determine the link status
 *     - fixed bad ifr_data pointer assignments in bond_ioctl
 *     - corrected mode 1 being reported as active-backup in bond_get_info;
 *       also added text to distinguish type of load balancing (rr or xor)
 *     - change arp_ip_target module param from "1-12s" (array of 12 ptrs)
 *       to "s" (a single ptr)
 *
 * 2002/08/30 - Jay Vosburgh <fubar at us dot ibm dot com>
 *     - Removed acquisition of xmit_lock in set_multicast_list; caused
 *       deadlock on SMP (lock is held by caller).
 *     - Revamped SIOCGMIIPHY, SIOCGMIIREG portion of bond_check_dev_link().
 *
 * 2002/09/18 - Jay Vosburgh <fubar at us dot ibm dot com>
 *     - Fixed up bond_check_dev_link() (and callers): removed some magic
 *       numbers, banished local MII_ defines, wrapped ioctl calls to
 *       prevent EFAULT errors
 *
 * 2002/9/30 - Jay Vosburgh <fubar at us dot ibm dot com>
 *     - make sure the ip target matches the arp_target before saving the
 *       hw address.
 *
 * 2002/9/30 - Dan Eisner <eisner at 2robots dot com>
 *     - make sure my_ip is set before taking down the link, since
 *       not all switches respond if the source ip is not set.
 *
 * 2002/10/8 - Janice Girouard <girouard at us dot ibm dot com>
 *     - read in the local ip address when enslaving a device
 *     - add primary support
 *     - make sure 2*arp_interval has passed when a new device
 *       is brought on-line before taking it down.
 *
 * 2002/09/11 - Philippe De Muyter <phdm at macqel dot be>
 *     - Added bond_xmit_broadcast logic.
 *     - Added bond_mode() support function.
 *
 * 2002/10/26 - Laurent Deniel <laurent.deniel at free.fr>
 *     - allow to register multicast addresses only on active slave
 *       (useful in active-backup mode)
 *     - add multicast module parameter
 *     - fix deletion of multicast groups after unloading module
 *
 * 2002/11/06 - Kameshwara Rayaprolu <kameshwara.rao * wipro_com>
 *     - Changes to prevent panic from closing the device twice; if we close
 *       the device in bond_release, we must set the original_flags to down
 *       so it won't be closed again by the network layer.
 *
 * 2002/11/07 - Tony Cureington <tony.cureington * hp_com>
 *     - Fix arp_target_hw_addr memory leak
 *     - Created activebackup_arp_monitor function to handle arp monitoring
 *       in active backup mode - the bond_arp_monitor had several problems...
 *       such as allowing slaves to tx arps sequentially without any delay
 *       for a response
 *     - Renamed bond_arp_monitor to loadbalance_arp_monitor and re-wrote
 *       this function to just handle arp monitoring in load-balancing mode;
 *       it is a lot more compact now
 *     - Changes to ensure one and only one slave transmits in active-backup
 *       mode
 *     - Robustesize parameters; warn users about bad combinations of
 *       parameters; also if miimon is specified and a network driver does
 *       not support MII or ETHTOOL, inform the user of this
 *     - Changes to support link_failure_count when in arp monitoring mode
 *     - Fix up/down delay reported in /proc
 *     - Added version; log version; make version available from "modinfo -d"
 *     - Fixed problem in bond_check_dev_link - if the first IOCTL (SIOCGMIIPH)
 *       failed, the ETHTOOL ioctl never got a chance
 *
 * 2002/11/16 - Laurent Deniel <laurent.deniel at free.fr>
 *     - fix multicast handling in activebackup_arp_monitor
 *     - remove one unnecessary and confusing curr_active_slave == slave test
 *       in activebackup_arp_monitor
 *
 *  2002/11/17 - Laurent Deniel <laurent.deniel at free.fr>
 *     - fix bond_slave_info_query when slave_id = num_slaves
 *
 *  2002/11/19 - Janice Girouard <girouard at us dot ibm dot com>
 *     - correct ifr_data reference.  Update ifr_data reference
 *       to mii_ioctl_data struct values to avoid confusion.
 *
 *  2002/11/22 - Bert Barbe <bert.barbe at oracle dot com>
 *      - Add support for multiple arp_ip_target
 *
 *  2002/12/13 - Jay Vosburgh <fubar at us dot ibm dot com>
 *      - Changed to allow text strings for mode and multicast, e.g.,
 *        insmod bonding mode=active-backup.  The numbers still work.
 *        One change: an invalid choice will cause module load failure,
 *        rather than the previous behavior of just picking one.
 *      - Minor cleanups; got rid of dup ctype stuff, atoi function
 *
 * 2003/02/07 - Jay Vosburgh <fubar at us dot ibm dot com>
 *      - Added use_carrier module parameter that causes miimon to
 *        use netif_carrier_ok() test instead of MII/ETHTOOL ioctls.
 *      - Minor cleanups; consolidated ioctl calls to one function.
 *
 * 2003/02/07 - Tony Cureington <tony.cureington * hp_com>
 *      - Fix bond_mii_monitor() logic error that could result in
 *        bonding round-robin mode ignoring links after failover/recovery
 *
 * 2003/03/17 - Jay Vosburgh <fubar at us dot ibm dot com>
 *      - kmalloc fix (GFP_KERNEL to GFP_ATOMIC) reported by
 *        Shmulik dot Hen at intel.com.
 *      - Based on discussion on mailing list, changed use of
 *        update_slave_cnt(), created wrapper functions for adding/removing
 *        slaves, changed bond_xmit_xor() to check slave_cnt instead of
 *        checking slave and slave->dev (which only worked by accident).
 *      - Misc code cleanup: get arp_send() prototype from header file,
 *        add max_bonds to bonding.txt.
 *
 * 2003/03/18 - Tsippy Mendelson <tsippy.mendelson at intel dot com> and
 *              Shmulik Hen <shmulik.hen at intel dot com>
 *      - Make sure only bond_attach_slave() and bond_detach_slave() can
 *        manipulate the slave list, including slave_cnt, even when in
 *        bond_release_all().
 *      - Fixed hang in bond_release() with traffic running:
 *        netdev_set_master() must not be called from within the bond lock.
 *
 * 2003/03/18 - Tsippy Mendelson <tsippy.mendelson at intel dot com> and
 *              Shmulik Hen <shmulik.hen at intel dot com>
 *      - Fixed hang in bond_enslave() with traffic running:
 *        netdev_set_master() must not be called from within the bond lock.
 *
 * 2003/03/18 - Amir Noam <amir.noam at intel dot com>
 *      - Added support for getting slave's speed and duplex via ethtool.
 *        Needed for 802.3ad and other future modes.
 *
 * 2003/03/18 - Tsippy Mendelson <tsippy.mendelson at intel dot com> and
 *              Shmulik Hen <shmulik.hen at intel dot com>
 *      - Enable support of modes that need to use the unique mac address of
 *        each slave.
 *        * bond_enslave(): Moved setting the slave's mac address, and
 *          openning it, from the application to the driver. This breaks
 *          backward comaptibility with old versions of ifenslave that open
 *           the slave before enalsving it !!!.
 *        * bond_release(): The driver also takes care of closing the slave
 *          and restoring its original mac address.
 *      - Removed the code that restores all base driver's flags.
 *        Flags are automatically restored once all undo stages are done
 *        properly.
 *      - Block possibility of enslaving before the master is up. This
 *        prevents putting the system in an unstable state.
 *
 * 2003/03/18 - Amir Noam <amir.noam at intel dot com>,
 *              Tsippy Mendelson <tsippy.mendelson at intel dot com> and
 *              Shmulik Hen <shmulik.hen at intel dot com>
 *      - Added support for IEEE 802.3ad Dynamic link aggregation mode.
 *
 * 2003/05/01 - Amir Noam <amir.noam at intel dot com>
 *      - Added ABI version control to restore compatibility between
 *        new/old ifenslave and new/old bonding.
 *
 * 2003/05/01 - Shmulik Hen <shmulik.hen at intel dot com>
 *      - Fixed bug in bond_release_all(): save old value of curr_active_slave
 *        before setting it to NULL.
 *      - Changed driver versioning scheme to include version number instead
 *        of release date (that is already in another field). There are 3
 *        fields X.Y.Z where:
 *              X - Major version - big behavior changes
 *              Y - Minor version - addition of features
 *              Z - Extra version - minor changes and bug fixes
 *        The current version is 1.0.0 as a base line.
 *
 * 2003/05/01 - Tsippy Mendelson <tsippy.mendelson at intel dot com> and
 *              Amir Noam <amir.noam at intel dot com>
 *      - Added support for lacp_rate module param.
 *      - Code beautification and style changes (mainly in comments).
 *        new version - 1.0.1
 *
 * 2003/05/01 - Shmulik Hen <shmulik.hen at intel dot com>
 *      - Based on discussion on mailing list, changed locking scheme
 *        to use lock/unlock or lock_bh/unlock_bh appropriately instead
 *        of lock_irqsave/unlock_irqrestore. The new scheme helps exposing
 *        hidden bugs and solves system hangs that occurred due to the fact
 *        that holding lock_irqsave doesn't prevent softirqs from running.
 *        This also increases total throughput since interrupts are not
 *        blocked on each transmitted packets or monitor timeout.
 *        new version - 2.0.0
 *
 * 2003/05/01 - Shmulik Hen <shmulik.hen at intel dot com>
 *      - Added support for Transmit load balancing mode.
 *      - Concentrate all assignments of curr_active_slave to a single point
 *        so specific modes can take actions when the primary adapter is
 *        changed.
 *      - Take the updelay parameter into consideration during bond_enslave
 *        since some adapters loose their link during setting the device.
 *      - Renamed bond_3ad_link_status_changed() to
 *        bond_3ad_handle_link_change() for compatibility with TLB.
 *        new version - 2.1.0
 *
 * 2003/05/01 - Tsippy Mendelson <tsippy.mendelson at intel dot com>
 *      - Added support for Adaptive load balancing mode which is
 *        equivalent to Transmit load balancing + Receive load balancing.
 *        new version - 2.2.0
 *
 * 2003/05/15 - Jay Vosburgh <fubar at us dot ibm dot com>
 *      - Applied fix to activebackup_arp_monitor posted to bonding-devel
 *        by Tony Cureington <tony.cureington * hp_com>.  Fixes ARP
 *        monitor endless failover bug.  Version to 2.2.10
 *
 * 2003/05/20 - Amir Noam <amir.noam at intel dot com>
 *      - Fixed bug in ABI version control - Don't commit to a specific
 *        ABI version if receiving unsupported ioctl commands.
 *
 * 2003/05/22 - Jay Vosburgh <fubar at us dot ibm dot com>
 *      - Fix ifenslave -c causing bond to loose existing routes;
 *        added bond_set_mac_address() that doesn't require the
 *        bond to be down.
 *      - In conjunction with fix for ifenslave -c, in
 *        bond_change_active(), changing to the already active slave
 *        is no longer an error (it successfully does nothing).
 *
 * 2003/06/30 - Amir Noam <amir.noam at intel dot com>
 *      - Fixed bond_change_active() for ALB/TLB modes.
 *        Version to 2.2.14.
 *
 * 2003/07/29 - Amir Noam <amir.noam at intel dot com>
 *      - Fixed ARP monitoring bug.
 *        Version to 2.2.15.
 *
 * 2003/07/31 - Willy Tarreau <willy at ods dot org>
 *      - Fixed kernel panic when using ARP monitoring without
 *        setting bond's IP address.
 *        Version to 2.2.16.
 *
 * 2003/08/06 - Amir Noam <amir.noam at intel dot com>
 *      - Back port from 2.6: use alloc_netdev(); fix /proc handling;
 *        made stats a part of bond struct so no need to allocate
 *        and free it separately; use standard list operations instead
 *        of pre-allocated array of bonds.
 *        Version to 2.3.0.
 *
 * 2003/08/07 - Jay Vosburgh <fubar at us dot ibm dot com>,
 *             Amir Noam <amir.noam at intel dot com> and
 *             Shmulik Hen <shmulik.hen at intel dot com>
 *      - Propagating master's settings: Distinguish between modes that
 *        use a primary slave from those that don't, and propagate settings
 *        accordingly; Consolidate change_active opeartions and add
 *        reselect_active and find_best opeartions; Decouple promiscuous
 *        handling from the multicast mode setting; Add support for changing
 *        HW address and MTU with proper unwind; Consolidate procfs code,
 *        add CHANGENAME handler; Enhance netdev notification handling.
 *        Version to 2.4.0.
 *
 * 2003/09/15 - Stephen Hemminger <shemminger at osdl dot org>,
 *             Amir Noam <amir.noam at intel dot com>
 *      - Convert /proc to seq_file interface.
 *        Change /proc/net/bondX/info to /proc/net/bonding/bondX.
 *        Set version to 2.4.1.
 *
 * 2003/11/20 - Amir Noam <amir.noam at intel dot com>
 *      - Fix /proc creation/destruction.
 *
 * 2003/12/01 - Shmulik Hen <shmulik.hen at intel dot com>
 *      - Massive cleanup - Set version to 2.5.0
 *        Code changes:
 *        o Consolidate format of prints and debug prints.
 *        o Remove bonding_t/slave_t typedefs and consolidate all casts.
 *        o Remove dead code and unnecessary checks.
 *        o Consolidate starting/stopping timers.
 *        o Consolidate handling of primary module param throughout the code.
 *        o Removed multicast module param support - all settings are done
 *          according to mode.
 *        o Slave list iteration - bond is no longer part of the list,
 *          added cyclic list iteration macros.
 *        o Consolidate error handling in all xmit functions.
 *        Style changes:
 *        o Consolidate function naming and declarations.
 *        o Consolidate function params and local variables names.
 *        o Consolidate return values.
 *        o Consolidate curly braces.
 *        o Consolidate conditionals format.
 *        o Change struct member names and types.
 *        o Chomp trailing spaces, remove empty lines, fix indentations.
 *        o Re-organize code according to context.
 *
 * 2003/12/30 - Amir Noam <amir.noam at intel dot com>
 *      - Fixed: Cannot remove and re-enslave the original active slave.
 *      - Fixed: Releasing the original active slave causes mac address
 *               duplication.
 *      - Add support for slaves that use ethtool_ops.
 *        Set version to 2.5.3.
 *
 * 2004/01/05 - Amir Noam <amir.noam at intel dot com>
 *      - Save bonding parameters per bond instead of using the global values.
 *        Set version to 2.5.4.
 *
 * 2004/01/14 - Shmulik Hen <shmulik.hen at intel dot com>
 *      - Enhance VLAN support:
 *        * Add support for VLAN hardware acceleration capable slaves.
 *        * Add capability to tag self generated packets in ALB/TLB modes.
 *        Set version to 2.6.0.
 * 2004/10/29 - Mitch Williams <mitch.a.williams at intel dot com>
 *      - Fixed bug when unloading module while using 802.3ad.  If
 *        spinlock debugging is turned on, this causes a stack dump.
 *        Solution is to move call to dev_remove_pack outside of the
 *        spinlock.
 *        Set version to 2.6.1.
 * 2005/06/05 - Jay Vosburgh <fubar@us.ibm.com>
 *      - Support for generating gratuitous ARPs in active-backup mode.
 *        Includes support for VLAN tagging all bonding-generated ARPs
 *        as needed.  Set version to 2.6.2.
 * 2005/06/08 - Jason Gabler <jygabler at lbl dot gov>
 *      - alternate hashing policy support for mode 2
 *        * Added kernel parameter "xmit_hash_policy" to allow the selection
 *          of different hashing policies for mode 2.  The original mode 2
 *          policy is the default, now found in xmit_hash_policy_layer2().
 *        * Added xmit_hash_policy_layer34()
 *      - Modified by Jay Vosburgh <fubar@us.ibm.com> to also support mode 4.
 *        Set version to 2.6.3.
 */

//#define BONDING_DEBUG 1

#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched.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 <asm/system.h>
#include <asm/io.h>
#include <asm/dma.h>
#include <asm/uaccess.h>
#include <linux/errno.h>
#include <linux/netdevice.h>
#include <linux/inetdevice.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 <net/route.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 miimon       = BOND_LINK_MON_INTERV;
static int updelay      = 0;
static int downdelay    = 0;
static int use_carrier  = 1;
static char *mode       = NULL;
static char *primary    = NULL;
static char *lacp_rate  = NULL;
static char *xmit_hash_policy = NULL;
static int arp_interval = BOND_LINK_ARP_INTERV;
static char *arp_ip_target[BOND_MAX_ARP_TARGETS] = { NULL, };

module_param(max_bonds, int, 0);
MODULE_PARM_DESC(max_bonds, "Max number of bonded devices");
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 round robin, 1 for active-backup, 2 for xor");
module_param(primary, charp, 0);
MODULE_PARM_DESC(primary, "Primary network device to use");
module_param(lacp_rate, charp, 0);
MODULE_PARM_DESC(lacp_rate, "LACPDU tx rate to request from 802.3ad partner (slow/fast)");
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");

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

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

static LIST_HEAD(bond_dev_list);

#ifdef CONFIG_PROC_FS
static struct proc_dir_entry *bond_proc_dir = NULL;
#endif

static u32 arp_target[BOND_MAX_ARP_TARGETS] = { 0, } ;
static int arp_ip_count = 0;
static int bond_mode    = BOND_MODE_ROUNDROBIN;
static int xmit_hashtype= BOND_XMIT_POLICY_LAYER2;
static int lacp_fast    = 0;
static int app_abi_ver  = 0;
static int orig_app_abi_ver = -1; /* This is used to save the first ABI version
                                   * we receive from the application. Once set,
                                   * it won't be changed, and the module will
                                   * refuse to enslave/release interfaces if the
                                   * command comes from an application using
                                   * another ABI version.
                                   */
struct bond_parm_tbl {
        char *modename;
        int mode;
};

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

static 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},
};

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

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

static inline void bond_set_mode_ops(struct bonding *bond, int mode);
static void bond_send_gratuitous_arp(struct bonding *bond);

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

static const char *bond_mode_name(int mode)
{
        switch (mode) {
        case BOND_MODE_ROUNDROBIN :
                return "load balancing (round-robin)";
        case BOND_MODE_ACTIVEBACKUP :
                return "fault-tolerance (active-backup)";
        case BOND_MODE_XOR :
                return "load balancing (xor)";
        case BOND_MODE_BROADCAST :
                return "fault-tolerance (broadcast)";
        case BOND_MODE_8023AD:
                return "IEEE 802.3ad Dynamic link aggregation";
        case BOND_MODE_TLB:
                return "transmit load balancing";
        case BOND_MODE_ALB:
                return "adaptive load balancing";
        default:
                return "unknown";
        }
}

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

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

        vlan = kmalloc(sizeof(struct vlan_entry), GFP_KERNEL);
        if (!vlan) {
                return -ENOMEM;
        }

        INIT_LIST_HEAD(&vlan->vlan_list);
        vlan->vlan_id = vlan_id;
        vlan->vlan_ip = 0;

        write_lock_bh(&bond->lock);

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

        write_unlock_bh(&bond->lock);

        dprintk("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, *next;
        int res = -ENODEV;

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

        write_lock_bh(&bond->lock);

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

                        if ((bond->params.mode == BOND_MODE_TLB) ||
                            (bond->params.mode == BOND_MODE_ALB)) {
                                bond_alb_clear_vlan(bond, vlan_id);
                        }

                        dprintk("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;
                }
        }

        dprintk("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) {
                        dprintk("found VLAN challenged slave - %s\n",
                                slave->dev->name);
                        return 1;
                }
        }

        dprintk("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 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 = bond_dev->priv;
        struct slave *slave;
        int i;

        bond->vlgrp = grp;

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

                if ((slave_dev->features & NETIF_F_HW_VLAN_RX) &&
                    slave_dev->vlan_rx_register) {
                        slave_dev->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 = bond_dev->priv;
        struct slave *slave;
        int i, res;

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

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

        res = bond_add_vlan(bond, vid);
        if (res) {
                printk(KERN_ERR DRV_NAME
                       ": %s: 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 = bond_dev->priv;
        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;

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

        res = bond_del_vlan(bond, vid);
        if (res) {
                printk(KERN_ERR DRV_NAME
                       ": %s: 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;

        write_lock_bh(&bond->lock);

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

        if ((slave_dev->features & NETIF_F_HW_VLAN_RX) &&
            slave_dev->vlan_rx_register) {
                slave_dev->vlan_rx_register(slave_dev, bond->vlgrp);
        }

        if (!(slave_dev->features & NETIF_F_HW_VLAN_FILTER) ||
            !(slave_dev->vlan_rx_add_vid)) {
                goto out;
        }

        list_for_each_entry(vlan, &bond->vlan_list, vlan_list) {
                slave_dev->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)
{
        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_dev->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 = bond->vlgrp->vlan_devices[vlan->vlan_id];
                slave_dev->vlan_rx_kill_vid(slave_dev, vlan->vlan_id);
                bond->vlgrp->vlan_devices[vlan->vlan_id] = vlan_dev;
        }

unreg:
        if ((slave_dev->features & NETIF_F_HW_VLAN_RX) &&
            slave_dev->vlan_rx_register) {
                slave_dev->vlan_rx_register(slave_dev, NULL);
        }

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

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

/*
 * 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;
        static int (* ioctl)(struct net_device *, struct ifreq *, int);
        struct ifreq ifr;
        struct ethtool_cmd etool;

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

        if (slave_dev->ethtool_ops) {
                u32 res;

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

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

                goto verify;
        }

        ioctl = slave_dev->do_ioctl;
        strncpy(ifr.ifr_name, slave_dev->name, IFNAMSIZ);
        etool.cmd = ETHTOOL_GSET;
        ifr.ifr_data = (char*)&etool;
        if (!ioctl || (IOCTL(slave_dev, &ifr, SIOCETHTOOL) < 0)) {
                return -1;
        }

verify:
        switch (etool.speed) {
        case SPEED_10:
        case SPEED_100:
        case SPEED_1000:
                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(),
 * depening 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)
{
        static int (* ioctl)(struct net_device *, struct ifreq *, int);
        struct ifreq ifr;
        struct mii_ioctl_data *mii;
        struct ethtool_value etool;

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

        ioctl = slave_dev->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);
                        }
                }
        }

        /* try SIOCETHTOOL ioctl, some drivers cache ETHTOOL_GLINK */
        /* for a period of time so we attempt to get link status   */
        /* from it last if the above MII ioctls fail...            */
        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;
                }
        }

        if (ioctl) {
                strncpy(ifr.ifr_name, slave_dev->name, IFNAMSIZ);
                etool.cmd = ETHTOOL_GLINK;
                ifr.ifr_data = (char*)&etool;
                if (IOCTL(slave_dev, &ifr, SIOCETHTOOL) == 0) {
                        if (etool.data == 1) {
                                return BMSR_LSTATUS;
                        } else {
                                dprintk("SIOCETHTOOL shows link down\n");
                                return 0;
                        }
                }
        }

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

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

/*
 * Returns 0 if dmi1 and dmi2 are the same, non-0 otherwise
 */
static inline int bond_is_dmi_same(struct dev_mc_list *dmi1, struct dev_mc_list *dmi2)
{
        return memcmp(dmi1->dmi_addr, dmi2->dmi_addr, dmi1->dmi_addrlen) == 0 &&
                        dmi1->dmi_addrlen == dmi2->dmi_addrlen;
}

/*
 * returns dmi entry if found, NULL otherwise
 */
static struct dev_mc_list *bond_mc_list_find_dmi(struct dev_mc_list *dmi, struct dev_mc_list *mc_list)
{
        struct dev_mc_list *idmi;

        for (idmi = mc_list; idmi; idmi = idmi->next) {
                if (bond_is_dmi_same(dmi, idmi)) {
                        return idmi;
                }
        }

        return NULL;
}

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

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

/*
 * Add a Multicast address to slaves
 * according to mode
 */
static void bond_mc_add(struct bonding *bond, void *addr, int alen)
{
        if (USES_PRIMARY(bond->params.mode)) {
                /* write lock already acquired */
                if (bond->curr_active_slave) {
                        dev_mc_add(bond->curr_active_slave->dev, addr, alen, 0);
                }
        } else {
                struct slave *slave;
                int i;
                bond_for_each_slave(bond, slave, i) {
                        dev_mc_add(slave->dev, addr, alen, 0);
                }
        }
}

/*
 * Remove a multicast address from slave
 * according to mode
 */
static void bond_mc_delete(struct bonding *bond, void *addr, int alen)
{
        if (USES_PRIMARY(bond->params.mode)) {
                /* write lock already acquired */
                if (bond->curr_active_slave) {
                        dev_mc_delete(bond->curr_active_slave->dev, addr, alen, 0);
                }
        } else {
                struct slave *slave;
                int i;
                bond_for_each_slave(bond, slave, i) {
                        dev_mc_delete(slave->dev, addr, alen, 0);
                }
        }
}

/*
 * Totally destroys the mc_list in bond
 */
static void bond_mc_list_destroy(struct bonding *bond)
{
        struct dev_mc_list *dmi;

        dmi = bond->mc_list;
        while (dmi) {
                bond->mc_list = dmi->next;
                kfree(dmi);
                dmi = bond->mc_list;
        }
}

/*
 * Copy all the Multicast addresses from src to the bonding device dst
 */
static int bond_mc_list_copy(struct dev_mc_list *mc_list, struct bonding *bond, int gpf_flag)
{
        struct dev_mc_list *dmi, *new_dmi;

        for (dmi = mc_list; dmi; dmi = dmi->next) {
                new_dmi = kmalloc(sizeof(struct dev_mc_list), gpf_flag);

                if (!new_dmi) {
                        /* FIXME: Potential memory leak !!! */
                        return -ENOMEM;
                }

                new_dmi->next = bond->mc_list;
                bond->mc_list = new_dmi;
                new_dmi->dmi_addrlen = dmi->dmi_addrlen;
                memcpy(new_dmi->dmi_addr, dmi->dmi_addr, dmi->dmi_addrlen);
                new_dmi->dmi_users = dmi->dmi_users;
                new_dmi->dmi_gusers = dmi->dmi_gusers;
        }

        return 0;
}

/*
 * 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 = bond_dev->priv;
        struct dev_mc_list *dmi;

        for (dmi = bond_dev->mc_list; dmi; dmi = dmi->next) {
                dev_mc_delete(slave_dev, dmi->dmi_addr, dmi->dmi_addrlen, 0);
        }

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

                dev_mc_delete(slave_dev, lacpdu_multicast, ETH_ALEN, 0);
        }
}

/*--------------------------- 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 dev_mc_list *dmi;

        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);
                }

                for (dmi = bond->dev->mc_list; dmi; dmi = dmi->next) {
                        dev_mc_delete(old_active->dev, dmi->dmi_addr, dmi->dmi_addrlen, 0);
                }
        }

        if (new_active) {
                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);
                }

                for (dmi = bond->dev->mc_list; dmi; dmi = dmi->next) {
                        dev_mc_add(new_active->dev, dmi->dmi_addr, dmi->dmi_addrlen, 0);
                }
        }
}

/**
 * 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 = old_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 */
                }
        }

        /* first try the primary link; if arping, a link must tx/rx traffic
         * before it can be considered the curr_active_slave - also, we would skip
         * slaves between the curr_active_slave and primary_slave that may be up
         * and able to arp
         */
        if ((bond->primary_slave) &&
            (!bond->params.arp_interval) &&
            (IS_UP(bond->primary_slave->dev))) {
                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 (IS_UP(new_active->dev)) {
                        if (new_active->link == BOND_LINK_UP) {
                                return new_active;
                        } else if (new_active->link == BOND_LINK_BACK) {
                                /* 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.
 *
 * Warning: Caller must hold curr_slave_lock for writing.
 */
static 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) {
                if (new_active->link == BOND_LINK_BACK) {
                        if (USES_PRIMARY(bond->params.mode)) {
                                printk(KERN_INFO DRV_NAME
                                       ": %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;
                        new_active->jiffies = jiffies;

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

                        if ((bond->params.mode == BOND_MODE_TLB) ||
                            (bond->params.mode == BOND_MODE_ALB)) {
                                bond_alb_handle_link_change(bond, new_active, BOND_LINK_UP);
                        }
                } else {
                        if (USES_PRIMARY(bond->params.mode)) {
                                printk(KERN_INFO DRV_NAME
                                       ": %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->params.mode == BOND_MODE_TLB) ||
            (bond->params.mode == BOND_MODE_ALB)) {
                bond_alb_handle_active_change(bond, 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);
                }
                bond_send_gratuitous_arp(bond);
        }
}

/**
 * bond_select_active_slave - select a new active slave, if needed
 * @bond: our bonding struct
 *
 * This functions shoud 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.
 *
 * Warning: Caller must hold curr_slave_lock for writing.
 */
static void bond_select_active_slave(struct bonding *bond)
{
        struct slave *best_slave;

        best_slave = bond_find_best_slave(bond);
        if (best_slave != bond->curr_active_slave) {
                bond_change_active_slave(bond, best_slave);
        }
}

/*--------------------------- 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)
{
        dprintk("bond_dev=%p\n", bond_dev);
        dprintk("slave_dev=%p\n", slave_dev);
        dprintk("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_INTERSECT_FEATURES \
        (NETIF_F_SG|NETIF_F_IP_CSUM|NETIF_F_NO_CSUM|NETIF_F_HW_CSUM)

/* 
 * Compute the features available to the bonding device by 
 * intersection of all of the slave devices' BOND_INTERSECT_FEATURES.
 * Call this after attaching or detaching a slave to update the 
 * bond's features.
 */
static int bond_compute_features(struct bonding *bond)
{
        int i;
        struct slave *slave;
        struct net_device *bond_dev = bond->dev;
        int features = bond->bond_features;

        bond_for_each_slave(bond, slave, i) {
                struct net_device * slave_dev = slave->dev;
                if (i == 0) {
                        features |= BOND_INTERSECT_FEATURES;
                }
                features &=
                        ~(~slave_dev->features & BOND_INTERSECT_FEATURES);
        }

        /* turn off NETIF_F_SG if we need a csum and h/w can't do it */
        if ((features & NETIF_F_SG) && 
                !(features & (NETIF_F_IP_CSUM |
                              NETIF_F_NO_CSUM |
                              NETIF_F_HW_CSUM))) {
                features &= ~NETIF_F_SG;
        }

        bond_dev->features = features;

        return 0;
}

/* enslave device <slave> to bond device <master> */
static int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
{
        struct bonding *bond = bond_dev->priv;
        struct slave *new_slave = NULL;
        struct dev_mc_list *dmi;
        struct sockaddr addr;
        int link_reporting;
        int old_features = bond_dev->features;
        int res = 0;

        if (!bond->params.use_carrier && slave_dev->ethtool_ops == NULL &&
                slave_dev->do_ioctl == NULL) {
                printk(KERN_WARNING DRV_NAME
                       ": Warning : no link monitoring support for %s\n",
                       slave_dev->name);
        }

        /* bond must be initialized by bond_open() before enslaving */
        if (!(bond_dev->flags & IFF_UP)) {
                dprintk("Error, master_dev is not up\n");
                return -EPERM;
        }

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

        /* vlan challenged mutual exclusion */
        /* no need to lock since we're protected by rtnl_lock */
        if (slave_dev->features & NETIF_F_VLAN_CHALLENGED) {
                dprintk("%s: NETIF_F_VLAN_CHALLENGED\n", slave_dev->name);
                if (!list_empty(&bond->vlan_list)) {
                        printk(KERN_ERR DRV_NAME
                               ": Error: cannot enslave VLAN "
                               "challenged slave %s on VLAN enabled "
                               "bond %s\n", slave_dev->name,
                               bond_dev->name);
                        return -EPERM;
                } else {
                        printk(KERN_WARNING DRV_NAME
                               ": Warning: enslaved VLAN challenged "
                               "slave %s. Adding VLANs will be blocked as "
                               "long as %s is part of bond %s\n",
                               slave_dev->name, slave_dev->name,
                               bond_dev->name);
                        bond_dev->features |= NETIF_F_VLAN_CHALLENGED;
                }
        } else {
                dprintk("%s: ! NETIF_F_VLAN_CHALLENGED\n", slave_dev->name);
                if (bond->slave_cnt == 0) {
                        /* First slave, and it is not VLAN challenged,
                         * so remove the block of adding VLANs over the bond.
                         */
                        bond_dev->features &= ~NETIF_F_VLAN_CHALLENGED;
                }
        }

        if (app_abi_ver >= 1) {
                /* The application is using an ABI, which requires the
                 * slave interface to be closed.
                 */
                if ((slave_dev->flags & IFF_UP)) {
                        printk(KERN_ERR DRV_NAME
                               ": Error: %s is up\n",
                               slave_dev->name);
                        res = -EPERM;
                        goto err_undo_flags;
                }

                if (slave_dev->set_mac_address == NULL) {
                        printk(KERN_ERR DRV_NAME
                               ": Error: The slave device you specified does "
                               "not support setting the MAC address.\n");
                        printk(KERN_ERR
                               "Your kernel likely does not support slave "
                               "devices.\n");

                        res = -EOPNOTSUPP;
                        goto err_undo_flags;
                }
        } else {
                /* The application is not using an ABI, which requires the
                 * slave interface to be open.
                 */
                if (!(slave_dev->flags & IFF_UP)) {
                        printk(KERN_ERR DRV_NAME
                               ": Error: %s is not running\n",
                               slave_dev->name);
                        res = -EINVAL;
                        goto err_undo_flags;
                }

                if ((bond->params.mode == BOND_MODE_8023AD) ||
                    (bond->params.mode == BOND_MODE_TLB)    ||
                    (bond->params.mode == BOND_MODE_ALB)) {
                        printk(KERN_ERR DRV_NAME
                               ": Error: to use %s mode, you must upgrade "
                               "ifenslave.\n",
                               bond_mode_name(bond->params.mode));
                        res = -EOPNOTSUPP;
                        goto err_undo_flags;
                }
        }

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

        memset(new_slave, 0, sizeof(struct slave));

        /* save slave's original flags before calling
         * netdev_set_master and dev_open
         */
        new_slave->original_flags = slave_dev->flags;

        if (app_abi_ver >= 1) {
                /* save slave's original ("permanent") mac address for
                 * modes that needs it, and for restoring it upon release,
                 * and then set it to the master's address
                 */
                memcpy(new_slave->perm_hwaddr, slave_dev->dev_addr, ETH_ALEN);

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

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

        res = netdev_set_master(slave_dev, bond_dev);
        if (res) {
                dprintk("Error %d calling netdev_set_master\n", res);
                if (app_abi_ver < 1) {
                        goto err_free;
                } else {
                        goto err_close;
                }
        }

        new_slave->dev = slave_dev;

        if ((bond->params.mode == BOND_MODE_TLB) ||
            (bond->params.mode == BOND_MODE_ALB)) {
                /* bond_alb_init_slave() must be called before all other stages since
                 * it might fail and we do not want to have to undo everything
                 */
                res = bond_alb_init_slave(bond, new_slave);
                if (res) {
                        goto err_unset_master;
                }
        }

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

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

                /* upload master's mc_list to new slave */
                for (dmi = bond_dev->mc_list; dmi; dmi = dmi->next) {
                        dev_mc_add (slave_dev, dmi->dmi_addr, dmi->dmi_addrlen, 0);
                }
        }

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

                dev_mc_add(slave_dev, lacpdu_multicast, ETH_ALEN, 0);
        }

        bond_add_vlans_on_slave(bond, slave_dev);

        write_lock_bh(&bond->lock);

        bond_attach_slave(bond, new_slave);

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

        bond_compute_features(bond);

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

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

        /* check for initial state */
        if (!bond->params.miimon ||
            (bond_check_dev_link(bond, slave_dev, 0) == BMSR_LSTATUS)) {
                if (bond->params.updelay) {
                        dprintk("Initial state of slave_dev is "
                                "BOND_LINK_BACK\n");
                        new_slave->link  = BOND_LINK_BACK;
                        new_slave->delay = bond->params.updelay;
                } else {
                        dprintk("Initial state of slave_dev is "
                                "BOND_LINK_UP\n");
                        new_slave->link  = BOND_LINK_UP;
                }
                new_slave->jiffies = jiffies;
        } else {
                dprintk("Initial state of slave_dev is "
                        "BOND_LINK_DOWN\n");
                new_slave->link  = BOND_LINK_DOWN;
        }

        if (bond_update_speed_duplex(new_slave) &&
            (new_slave->link != BOND_LINK_DOWN)) {
                printk(KERN_WARNING DRV_NAME
                       ": Warning: failed to get speed and duplex from %s, "
                       "assumed to be 100Mb/sec and Full.\n",
                       new_slave->dev->name);

                if (bond->params.mode == BOND_MODE_8023AD) {
                        printk(KERN_WARNING
                               "Operation of 802.3ad mode requires ETHTOOL "
                               "support in base driver for proper aggregator "
                               "selection.\n");
                }
        }

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

        switch (bond->params.mode) {
        case BOND_MODE_ACTIVEBACKUP:
                /* if we're in active-backup mode, we need one and only one active
                 * interface. The backup interfaces will have their NOARP flag set
                 * because we need them to be completely deaf and not to respond to
                 * any ARP request on the network to avoid fooling a switch. Thus,
                 * since we guarantee that curr_active_slave always point to the last
                 * usable interface, we just have to verify this interface's flag.
                 */
                if (((!bond->curr_active_slave) ||
                     (bond->curr_active_slave->dev->flags & IFF_NOARP)) &&
                    (new_slave->link != BOND_LINK_DOWN)) {
                        dprintk("This is the first active slave\n");
                        /* first slave or no active slave yet, and this link
                           is OK, so make this interface the active one */
                        bond_change_active_slave(bond, new_slave);
                } else {
                        dprintk("This is just a backup slave\n");
                        bond_set_slave_inactive_flags(new_slave);
                }
                break;
        case BOND_MODE_8023AD:
                /* in 802.3ad mode, the internal mechanism
                 * will activate the slaves in the selected
                 * aggregator
                 */
                bond_set_slave_inactive_flags(new_slave);
                /* if this is the first slave */
                if (bond->slave_cnt == 1) {
                        SLAVE_AD_INFO(new_slave).id = 1;
                        /* Initialize AD with the number of times that the AD timer is called in 1 second
                         * can be called only after the mac address of the bond is set
                         */
                        bond_3ad_initialize(bond, 1000/AD_TIMER_INTERVAL,
                                            bond->params.lacp_fast);
                } else {
                        SLAVE_AD_INFO(new_slave).id =
                                SLAVE_AD_INFO(new_slave->prev).id + 1;
                }

                bond_3ad_bind_slave(new_slave);
                break;
        case BOND_MODE_TLB:
        case BOND_MODE_ALB:
                new_slave->state = BOND_STATE_ACTIVE;
                if ((!bond->curr_active_slave) &&
                    (new_slave->link != BOND_LINK_DOWN)) {
                        /* first slave or no active slave yet, and this link
                         * is OK, so make this interface the active one
                         */
                        bond_change_active_slave(bond, new_slave);
                }
                break;
        default:
                dprintk("This slave is always active in trunk mode\n");

                /* always active in trunk mode */
                new_slave->state = BOND_STATE_ACTIVE;

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

        write_unlock_bh(&bond->lock);

        if (app_abi_ver < 1) {
                /*
                 * !!! This is to support old versions of ifenslave.
                 * We can remove this in 2.5 because our ifenslave takes
                 * care of this for us.
                 * We check to see if the master has a mac address yet.
                 * If not, we'll give it the mac address of our slave device.
                 */
                int ndx = 0;

                for (ndx = 0; ndx < bond_dev->addr_len; ndx++) {
                        dprintk("Checking ndx=%d of bond_dev->dev_addr\n",
                                ndx);
                        if (bond_dev->dev_addr[ndx] != 0) {
                                dprintk("Found non-zero byte at ndx=%d\n",
                                        ndx);
                                break;
                        }
                }

                if (ndx == bond_dev->addr_len) {
                        /*
                         * We got all the way through the address and it was
                         * all 0's.
                         */
                        dprintk("%s doesn't have a MAC address yet.  \n",
                                bond_dev->name);
                        dprintk("Going to give assign it from %s.\n",
                                slave_dev->name);
                        bond_sethwaddr(bond_dev, slave_dev);
                }
        }

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

        /* enslave is successful */
        return 0;

/* Undo stages on error */
err_unset_master:
        netdev_set_master(slave_dev, NULL);

err_close:
        dev_close(slave_dev);

err_restore_mac:
        memcpy(addr.sa_data, new_slave->perm_hwaddr, ETH_ALEN);
        addr.sa_family = slave_dev->type;
        dev_set_mac_address(slave_dev, &addr);

err_free:
        kfree(new_slave);

err_undo_flags:
        bond_dev->features = old_features;
 
        return res;
}

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

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

        write_lock_bh(&bond->lock);

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

        mac_addr_differ = memcmp(bond_dev->dev_addr,
                                 slave->perm_hwaddr,
                                 ETH_ALEN);
        if (!mac_addr_differ && (bond->slave_cnt > 1)) {
                printk(KERN_WARNING DRV_NAME
                       ": Warning: the permanent HWaddr of %s "
                       "- %02X:%02X:%02X:%02X:%02X:%02X - is "
                       "still in use by %s. Set the HWaddr of "
                       "%s to a different address to avoid "
                       "conflicts.\n",
                       slave_dev->name,
                       slave->perm_hwaddr[0],
                       slave->perm_hwaddr[1],
                       slave->perm_hwaddr[2],
                       slave->perm_hwaddr[3],
                       slave->perm_hwaddr[4],
                       slave->perm_hwaddr[5],
                       bond_dev->name,
                       slave_dev->name);
        }

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

        printk(KERN_INFO DRV_NAME
               ": %s: releasing %s interface %s\n",
               bond_dev->name,
               (slave->state == BOND_STATE_ACTIVE)
               ? "active" : "backup",
               slave_dev->name);

        oldcurrent = bond->curr_active_slave;

        bond->current_arp_slave = NULL;

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

        bond_compute_features(bond);

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

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

        if ((bond->params.mode == BOND_MODE_TLB) ||
            (bond->params.mode == BOND_MODE_ALB)) {
                /* Must be called only after the slave has been
                 * detached from the list and the curr_active_slave
                 * has been cleared (if our_slave == old_current),
                 * but before a new active slave is selected.
                 */
                bond_alb_deinit_slave(bond, slave);
        }

        if (oldcurrent == slave) {
                bond_select_active_slave(bond);

                if (!bond->curr_active_slave) {
                        printk(KERN_INFO DRV_NAME
                               ": %s: now running without any active "
                               "interface !\n",
                               bond_dev->name);
                }
        }

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

                if (list_empty(&bond->vlan_list)) {
                        bond_dev->features |= NETIF_F_VLAN_CHALLENGED;
                } else {
                        printk(KERN_WARNING DRV_NAME
                               ": Warning: clearing HW address of %s while it "
                               "still has VLANs.\n",
                               bond_dev->name);
                        printk(KERN_WARNING DRV_NAME
                               ": When re-adding slaves, make sure the bond's "
                               "HW address matches its VLANs'.\n");
                }
        } else if ((bond_dev->features & NETIF_F_VLAN_CHALLENGED) &&
                   !bond_has_challenged_slaves(bond)) {
                printk(KERN_INFO DRV_NAME
                       ": last VLAN challenged slave %s "
                       "left bond %s. VLAN blocking is removed\n",
                       slave_dev->name, bond_dev->name);
                bond_dev->features &= ~NETIF_F_VLAN_CHALLENGED;
        }

        write_unlock_bh(&bond->lock);

        bond_del_vlans_from_slave(bond, slave_dev);

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

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

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

        netdev_set_master(slave_dev, NULL);

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

        if (app_abi_ver >= 1) {
                /* restore original ("permanent") mac address */
                memcpy(addr.sa_data, slave->perm_hwaddr, ETH_ALEN);
                addr.sa_family = slave_dev->type;
                dev_set_mac_address(slave_dev, &addr);
        }

        /* restore the original state of the
         * IFF_NOARP flag that might have been
         * set by bond_set_slave_inactive_flags()
         */
        if ((slave->original_flags & IFF_NOARP) == 0) {
                slave_dev->flags &= ~IFF_NOARP;
        }

        kfree(slave);

        return 0;  /* deletion OK */
}

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

        write_lock_bh(&bond->lock);

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

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

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

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

                if ((bond->params.mode == BOND_MODE_TLB) ||
                    (bond->params.mode == BOND_MODE_ALB)) {
                        /* must be called only after the slave
                         * has been detached from the list
                         */
                        bond_alb_deinit_slave(bond, slave);
                }

                bond_compute_features(bond);

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

                bond_del_vlans_from_slave(bond, slave_dev);

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

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

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

                netdev_set_master(slave_dev, NULL);

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

                if (app_abi_ver >= 1) {
                        /* restore original ("permanent") mac address*/
                        memcpy(addr.sa_data, slave->perm_hwaddr, ETH_ALEN);
                        addr.sa_family = slave_dev->type;
                        dev_set_mac_address(slave_dev, &addr);
                }

                /* restore the original state of the IFF_NOARP flag that might have
                 * been set by bond_set_slave_inactive_flags()
                 */
                if ((slave->original_flags & IFF_NOARP) == 0) {
                        slave_dev->flags &= ~IFF_NOARP;
                }

                kfree(slave);

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

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

        if (list_empty(&bond->vlan_list)) {
                bond_dev->features |= NETIF_F_VLAN_CHALLENGED;
        } else {
                printk(KERN_WARNING DRV_NAME
                       ": Warning: clearing HW address of %s while it "
                       "still has VLANs.\n",
                       bond_dev->name);
                printk(KERN_WARNING DRV_NAME
                       ": When re-adding slaves, make sure the bond's "
                       "HW address matches its VLANs'.\n");
        }

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

out:
        write_unlock_bh(&bond->lock);

        return 0;
}

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

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

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

        write_lock_bh(&bond->lock);

        old_active = bond->curr_active_slave;
        new_active = bond_get_slave_by_dev(bond, slave_dev);

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

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

        write_unlock_bh(&bond->lock);

        return res;
}

static int bond_ethtool_ioctl(struct net_device *bond_dev, struct ifreq *ifr)
{
        struct ethtool_drvinfo info;
        void __user *addr = ifr->ifr_data;
        uint32_t cmd;

        if (get_user(cmd, (uint32_t __user *)addr)) {
                return -EFAULT;
        }

        switch (cmd) {
        case ETHTOOL_GDRVINFO:
                if (copy_from_user(&info, addr, sizeof(info))) {
                        return -EFAULT;
                }

                if (strcmp(info.driver, "ifenslave") == 0) {
                        int new_abi_ver;
                        char *endptr;

                        new_abi_ver = simple_strtoul(info.fw_version,
                                                     &endptr, 0);
                        if (*endptr) {
                                printk(KERN_ERR DRV_NAME
                                       ": Error: got invalid ABI "
                                       "version from application\n");

                                return -EINVAL;
                        }

                        if (orig_app_abi_ver == -1) {
                                orig_app_abi_ver  = new_abi_ver;
                        }

                        app_abi_ver = new_abi_ver;
                }

                strncpy(info.driver,  DRV_NAME, 32);
                strncpy(info.version, DRV_VERSION, 32);
                snprintf(info.fw_version, 32, "%d", BOND_ABI_VERSION);

                if (copy_to_user(addr, &info, sizeof(info))) {
                        return -EFAULT;
                }

                return 0;
        default:
                return -EOPNOTSUPP;
        }
}

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

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

        read_lock_bh(&bond->lock);
        info->num_slaves = bond->slave_cnt;
        read_unlock_bh(&bond->lock);

        return 0;
}

static int bond_slave_info_query(struct net_device *bond_dev, struct ifslave *info)
{
        struct bonding *bond = bond_dev->priv;
        struct slave *slave;
        int i, found = 0;

        if (info->slave_id < 0) {
                return -ENODEV;
        }

        read_lock_bh(&bond->lock);

        bond_for_each_slave(bond, slave, i) {
                if (i == (int)info->slave_id) {
                        found = 1;
                        break;
                }
        }

        read_unlock_bh(&bond->lock);

        if (found) {
                strcpy(info->slave_name, slave->dev->name);
                info->link = slave->link;
                info->state = slave->state;
                info->link_failure_count = slave->link_failure_count;
        } else {
                return -ENODEV;
        }

        return 0;
}

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

/* this function is called regularly to monitor each slave's link. */
static void bond_mii_monitor(struct net_device *bond_dev)
{
        struct bonding *bond = bond_dev->priv;
        struct slave *slave, *oldcurrent;
        int do_failover = 0;
        int delta_in_ticks;
        int i;

        read_lock(&bond->lock);

        delta_in_ticks = (bond->params.miimon * HZ) / 1000;

        if (bond->kill_timers) {
                goto out;
        }

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

        /* we will try to read the link status of each of our slaves, and
         * set their IFF_RUNNING flag appropriately. For each slave not
         * supporting MII status, we won't do anything so that a user-space
         * program could monitor the link itself if needed.
         */

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

        bond_for_each_slave(bond, slave, i) {
                struct net_device *slave_dev = slave->dev;
                int link_state;
                u16 old_speed = slave->speed;
                u8 old_duplex = slave->duplex;

                link_state = bond_check_dev_link(bond, slave_dev, 0);

                switch (slave->link) {
                case BOND_LINK_UP:      /* the link was up */
                        if (link_state == BMSR_LSTATUS) {
                                /* link stays up, nothing more to do */
                                break;
                        } else { /* link going down */
                                slave->link  = BOND_LINK_FAIL;
                                slave->delay = bond->params.downdelay;

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

                                if (bond->params.downdelay) {
                                        printk(KERN_INFO DRV_NAME
                                               ": %s: link status down for %s "
                                               "interface %s, disabling it in "
                                               "%d ms.\n",
                                               bond_dev->name,
                                               IS_UP(slave_dev)
                                               ? ((bond->params.mode == BOND_MODE_ACTIVEBACKUP)
                                                  ? ((slave == oldcurrent)
                                                     ? "active " : "backup ")
                                                  : "")
                                               : "idle ",
                                               slave_dev->name,
                                               bond->params.downdelay * bond->params.miimon);
                                }
                        }
                        /* no break ! fall through the BOND_LINK_FAIL test to
                           ensure proper action to be taken
                        */
                case BOND_LINK_FAIL:    /* the link has just gone down */
                        if (link_state != BMSR_LSTATUS) {
                                /* link stays down */
                                if (slave->delay <= 0) {
                                        /* link down for too long time */
                                        slave->link = BOND_LINK_DOWN;

                                        /* in active/backup mode, we must
                                         * completely disable this interface
                                         */
                                        if ((bond->params.mode == BOND_MODE_ACTIVEBACKUP) ||
                                            (bond->params.mode == BOND_MODE_8023AD)) {
                                                bond_set_slave_inactive_flags(slave);
                                        }

                                        printk(KERN_INFO DRV_NAME
                                               ": %s: link status definitely "
                                               "down for interface %s, "
                                               "disabling it\n",
                                               bond_dev->name,
                                               slave_dev->name);

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

                                        if ((bond->params.mode == BOND_MODE_TLB) ||
                                            (bond->params.mode == BOND_MODE_ALB)) {
                                                bond_alb_handle_link_change(bond, slave, BOND_LINK_DOWN);
                                        }

                                        if (slave == oldcurrent) {
                                                do_failover = 1;
                                        }
                                } else {
                                        slave->delay--;
                                }
                        } else {
                                /* link up again */
                                slave->link  = BOND_LINK_UP;
                                slave->jiffies = jiffies;
                                printk(KERN_INFO DRV_NAME
                                       ": %s: link status up again after %d "
                                       "ms for interface %s.\n",
                                       bond_dev->name,
                                       (bond->params.downdelay - slave->delay) * bond->params.miimon,
                                       slave_dev->name);
                        }
                        break;
                case BOND_LINK_DOWN:    /* the link was down */
                        if (link_state != BMSR_LSTATUS) {
                                /* the link stays down, nothing more to do */
                                break;
                        } else {        /* link going up */
                                slave->link  = BOND_LINK_BACK;
                                slave->delay = bond->params.updelay;

                                if (bond->params.updelay) {
                                        /* if updelay == 0, no need to
                                           advertise about a 0 ms delay */
                                        printk(KERN_INFO DRV_NAME
                                               ": %s: link status up for "
                                               "interface %s, enabling it "
                                               "in %d ms.\n",
                                               bond_dev->name,
                                               slave_dev->name,
                                               bond->params.updelay * bond->params.miimon);
                                }
                        }
                        /* no break ! fall through the BOND_LINK_BACK state in
                           case there's something to do.
                        */
                case BOND_LINK_BACK:    /* the link has just come back */
                        if (link_state != BMSR_LSTATUS) {
                                /* link down again */
                                slave->link  = BOND_LINK_DOWN;

                                printk(KERN_INFO DRV_NAME
                                       ": %s: link status down again after %d "
                                       "ms for interface %s.\n",
                                       bond_dev->name,
                                       (bond->params.updelay - slave->delay) * bond->params.miimon,
                                       slave_dev->name);
                        } else {
                                /* link stays up */
                                if (slave->delay == 0) {
                                        /* now the link has been up for long time enough */
                                        slave->link = BOND_LINK_UP;
                                        slave->jiffies = jiffies;

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

                                        printk(KERN_INFO DRV_NAME
                                               ": %s: link status definitely "
                                               "up for interface %s.\n",
                                               bond_dev->name,
                                               slave_dev->name);

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

                                        if ((bond->params.mode == BOND_MODE_TLB) ||
                                            (bond->params.mode == BOND_MODE_ALB)) {
                                                bond_alb_handle_link_change(bond, slave, BOND_LINK_UP);
                                        }

                                        if ((!oldcurrent) ||
                                            (slave == bond->primary_slave)) {
                                                do_failover = 1;
                                        }
                                } else {
                                        slave->delay--;
                                }
                        }
                        break;
                default:
                        /* Should not happen */
                        printk(KERN_ERR "bonding: Error: %s  Illegal value (link=%d)\n",
                               slave->dev->name, slave->link);
                        goto out;
                } /* end of switch (slave->link) */

                bond_update_speed_duplex(slave);

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

                        if (old_duplex != slave->duplex) {
                                bond_3ad_adapter_duplex_changed(slave);
                        }
                }

        } /* end of for */

        if (do_failover) {
                write_lock(&bond->curr_slave_lock);

                bond_select_active_slave(bond);

                if (oldcurrent && !bond->curr_active_slave) {
                        printk(KERN_INFO DRV_NAME
                               ": %s: now running without any active "
                               "interface !\n",
                               bond_dev->name);
                }

                write_unlock(&bond->curr_slave_lock);
        }

re_arm:
        if (bond->params.miimon) {
                mod_timer(&bond->mii_timer, jiffies + delta_in_ticks);
        }
out:
        read_unlock(&bond->lock);
}


static u32 bond_glean_dev_ip(struct net_device *dev)
{
        struct in_device *idev;
        struct in_ifaddr *ifa;
        u32 addr = 0;

        if (!dev)
                return 0;

        rcu_read_lock();
        idev = __in_dev_get_rcu(dev);
        if (!idev)
                goto out;

        ifa = idev->ifa_list;
        if (!ifa)
                goto out;

        addr = ifa->ifa_local;
out:
        rcu_read_unlock();
        return addr;
}

static int bond_has_ip(struct bonding *bond)
{
        struct vlan_entry *vlan, *vlan_next;

        if (bond->master_ip)
                return 1;

        if (list_empty(&bond->vlan_list))
                return 0;

        list_for_each_entry_safe(vlan, vlan_next, &bond->vlan_list,
                                 vlan_list) {
                if (vlan->vlan_ip)
                        return 1;
        }

        return 0;
}

/*
 * We go to the (large) trouble of VLAN tagging ARP frames because
 * switches in VLAN mode (especially if ports are configured as
 * "native" to a VLAN) might not pass non-tagged frames.
 */
static void bond_arp_send(struct net_device *slave_dev, int arp_op, u32 dest_ip, u32 src_ip, unsigned short vlan_id)
{
        struct sk_buff *skb;

        dprintk("arp %d on slave %s: dst %x src %x vid %d\n", arp_op,
               slave_dev->name, dest_ip, src_ip, vlan_id);
               
        skb = arp_create(arp_op, ETH_P_ARP, dest_ip, slave_dev, src_ip,
                         NULL, slave_dev->dev_addr, NULL);

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


static void bond_arp_send_all(struct bonding *bond, struct slave *slave)
{
        int i, vlan_id, rv;
        u32 *targets = bond->params.arp_targets;
        struct vlan_entry *vlan, *vlan_next;
        struct net_device *vlan_dev;
        struct flowi fl;
        struct rtable *rt;

        for (i = 0; (i < BOND_MAX_ARP_TARGETS) && targets[i]; i++) {
                dprintk("basa: target %x\n", targets[i]);
                if (list_empty(&bond->vlan_list)) {
                        dprintk("basa: empty vlan: arp_send\n");
                        bond_arp_send(slave->dev, ARPOP_REQUEST, targets[i],
                                      bond->master_ip, 0);
                        continue;
                }

                /*
                 * If VLANs are configured, we do a route lookup to
                 * determine which VLAN interface would be used, so we
                 * can tag the ARP with the proper VLAN tag.
                 */
                memset(&fl, 0, sizeof(fl));
                fl.fl4_dst = targets[i];
                fl.fl4_tos = RTO_ONLINK;

                rv = ip_route_output_key(&rt, &fl);
                if (rv) {
                        if (net_ratelimit()) {
                                printk(KERN_WARNING DRV_NAME
                             ": %s: no route to arp_ip_target %u.%u.%u.%u\n",
                                       bond->dev->name, NIPQUAD(fl.fl4_dst));
                        }
                        continue;
                }

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

                vlan_id = 0;
                list_for_each_entry_safe(vlan, vlan_next, &bond->vlan_list,
                                         vlan_list) {
                        vlan_dev = bond->vlgrp->vlan_devices[vlan->vlan_id];
                        if (vlan_dev == rt->u.dst.dev) {
                                vlan_id = vlan->vlan_id;
                                dprintk("basa: vlan match on %s %d\n",
                                       vlan_dev->name, vlan_id);
                                break;
                        }
                }

                if (vlan_id) {
                        ip_rt_put(rt);
                        bond_arp_send(slave->dev, ARPOP_REQUEST, targets[i],
                                      vlan->vlan_ip, vlan_id);
                        continue;
                }

                if (net_ratelimit()) {
                        printk(KERN_WARNING DRV_NAME
               ": %s: no path to arp_ip_target %u.%u.%u.%u via rt.dev %s\n",
                               bond->dev->name, NIPQUAD(fl.fl4_dst),
                               rt->u.dst.dev ? rt->u.dst.dev->name : "NULL");
                }
                ip_rt_put(rt);
        }
}

/*
 * Kick out a gratuitous ARP for an IP on the bonding master plus one
 * for each VLAN above us.
 */
static void bond_send_gratuitous_arp(struct bonding *bond)
{
        struct slave *slave = bond->curr_active_slave;
        struct vlan_entry *vlan;
        struct net_device *vlan_dev;

        dprintk("bond_send_grat_arp: bond %s slave %s\n", bond->dev->name,
                                slave ? slave->dev->name : "NULL");
        if (!slave)
                return;

        if (bond->master_ip) {
                bond_arp_send(slave->dev, ARPOP_REPLY, bond->master_ip,
                                  bond->master_ip, 0);
        }

        list_for_each_entry(vlan, &bond->vlan_list, vlan_list) {
                vlan_dev = bond->vlgrp->vlan_devices[vlan->vlan_id];
                if (vlan->vlan_ip) {
                        bond_arp_send(slave->dev, ARPOP_REPLY, vlan->vlan_ip,
                                      vlan->vlan_ip, vlan->vlan_id);
                }
        }
}

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

        read_lock(&bond->lock);

        delta_in_ticks = (bond->params.arp_interval * HZ) / 1000;

        if (bond->kill_timers) {
                goto out;
        }

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

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

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

                                slave->link  = BOND_LINK_UP;
                                slave->state = BOND_STATE_ACTIVE;

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

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

                                slave->link  = BOND_LINK_DOWN;
                                slave->state = BOND_STATE_BACKUP;

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

                                printk(KERN_INFO DRV_NAME
                                       ": %s: interface %s is now down.\n",
                                       bond_dev->name,
                                       slave->dev->name);

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

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

        if (do_failover) {
                write_lock(&bond->curr_slave_lock);

                bond_select_active_slave(bond);

                if (oldcurrent && !bond->curr_active_slave) {
                        printk(KERN_INFO DRV_NAME
                               ": %s: now running without any active "
                               "interface !\n",
                               bond_dev->name);
                }

                write_unlock(&bond->curr_slave_lock);
        }

re_arm:
        if (bond->params.arp_interval) {
                mod_timer(&bond->arp_timer, jiffies + delta_in_ticks);
        }
out:
        read_unlock(&bond->lock);
}

/*
 * When using arp monitoring in active-backup mode, this function is
 * called to determine if any backup slaves have went down or a new
 * current slave needs to be found.
 * The backup slaves never generate traffic, they are considered up by merely
 * receiving traffic. If the current slave goes down, each backup slave will
 * be given the opportunity to tx/rx an arp before being taken down - this
 * prevents all slaves from being taken down due to the current slave not
 * sending any traffic for the backups to receive. The arps are not necessarily
 * necessary, any tx and rx traffic will keep the current slave up. While any
 * rx traffic will keep the backup slaves up, the current slave is responsible
 * for generating traffic to keep them up regardless of any other traffic they
 * may have received.
 * see loadbalance_arp_monitor for arp monitoring in load balancing mode
 */
static void bond_activebackup_arp_mon(struct net_device *bond_dev)
{
        struct bonding *bond = bond_dev->priv;
        struct slave *slave;
        int delta_in_ticks;
        int i;

        read_lock(&bond->lock);

        delta_in_ticks = (bond->params.arp_interval * HZ) / 1000;

        if (bond->kill_timers) {
                goto out;
        }

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

        /* determine if any slave has come up or any backup slave has
         * gone down
         * TODO: what about up/down delay in arp mode? it wasn't here before
         *       so it can wait
         */
        bond_for_each_slave(bond, slave, i) {
                if (slave->link != BOND_LINK_UP) {
                        if ((jiffies - slave->dev->last_rx) <= delta_in_ticks) {

                                slave->link = BOND_LINK_UP;

                                write_lock(&bond->curr_slave_lock);

                                if ((!bond->curr_active_slave) &&
                                    ((jiffies - slave->dev->trans_start) <= delta_in_ticks)) {
                                        bond_change_active_slave(bond, slave);
                                        bond->current_arp_slave = NULL;
                                } else if (bond->curr_active_slave != slave) {
                                        /* this slave has just come up but we
                                         * already have a current slave; this
                                         * can also happen if bond_enslave adds
                                         * a new slave that is up while we are
                                         * searching for a new slave
                                         */
                                        bond_set_slave_inactive_flags(slave);
                                        bond->current_arp_slave = NULL;
                                }

                                if (slave == bond->curr_active_slave) {
                                        printk(KERN_INFO DRV_NAME
                                               ": %s: %s is up and now the "
                                               "active interface\n",
                                               bond_dev->name,
                                               slave->dev->name);
                                } else {
                                        printk(KERN_INFO DRV_NAME
                                               ": %s: backup interface %s is "
                                               "now up\n",
                                               bond_dev->name,
                                               slave->dev->name);
                                }

                                write_unlock(&bond->curr_slave_lock);
                        }
                } else {
                        read_lock(&bond->curr_slave_lock);

                        if ((slave != bond->curr_active_slave) &&
                            (!bond->current_arp_slave) &&
                            (((jiffies - slave->dev->last_rx) >= 3*delta_in_ticks) &&
                             bond_has_ip(bond))) {
                                /* a backup slave has gone down; three times
                                 * the delta allows the current slave to be
                                 * taken out before the backup slave.
                                 * note: a non-null current_arp_slave indicates
                                 * the curr_active_slave went down and we are
                                 * searching for a new one; under this
                                 * condition we only take the curr_active_slave
                                 * down - this gives each slave a chance to
                                 * tx/rx traffic before being taken out
                                 */

                                read_unlock(&bond->curr_slave_lock);

                                slave->link  = BOND_LINK_DOWN;

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

                                bond_set_slave_inactive_flags(slave);

                                printk(KERN_INFO DRV_NAME
                                       ": %s: backup interface %s is now down\n",
                                       bond_dev->name,
                                       slave->dev->name);
                        } else {
                                read_unlock(&bond->curr_slave_lock);
                        }
                }
        }

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

        if (slave) {
                /* if we have sent traffic in the past 2*arp_intervals but
                 * haven't xmit and rx traffic in that time interval, select
                 * a different slave. slave->jiffies is only updated when
                 * a slave first becomes the curr_active_slave - not necessarily
                 * after every arp; this ensures the slave has a full 2*delta
                 * before being taken out. if a primary is being used, check
                 * if it is up and needs to take over as the curr_active_slave
                 */
                if ((((jiffies - slave->dev->trans_start) >= (2*delta_in_ticks)) ||
            (((jiffies - slave->dev->last_rx) >= (2*delta_in_ticks)) &&
             bond_has_ip(bond))) &&
                    ((jiffies - slave->jiffies) >= 2*delta_in_ticks)) {

                        slave->link  = BOND_LINK_DOWN;

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

                        printk(KERN_INFO DRV_NAME
                               ": %s: link status down for active interface "
                               "%s, disabling it\n",
                               bond_dev->name,
                               slave->dev->name);

                        write_lock(&bond->curr_slave_lock);

                        bond_select_active_slave(bond);
                        slave = bond->curr_active_slave;

                        write_unlock(&bond->curr_slave_lock);

                        bond->current_arp_slave = slave;

                        if (slave) {
                                slave->jiffies = jiffies;
                        }
                } else if ((bond->primary_slave) &&
                           (bond->primary_slave != slave) &&
                           (bond->primary_slave->link == BOND_LINK_UP)) {
                        /* at this point, slave is the curr_active_slave */
                        printk(KERN_INFO DRV_NAME
                               ": %s: changing from interface %s to primary "
                               "interface %s\n",
                               bond_dev->name,
                               slave->dev->name,
                               bond->primary_slave->dev->name);

                        /* primary is up so switch to it */
                        write_lock(&bond->curr_slave_lock);
                        bond_change_active_slave(bond, bond->primary_slave);
                        write_unlock(&bond->curr_slave_lock);

                        slave = bond->primary_slave;
                        slave->jiffies = jiffies;
                } else {
                        bond->current_arp_slave = NULL;
                }

                /* the current slave must tx an arp to ensure backup slaves
                 * rx traffic
                 */
                if (slave && bond_has_ip(bond)) {
                        bond_arp_send_all(bond, slave);
                }
        }

        /* if we don't have a curr_active_slave, search for the next available
         * backup slave from the current_arp_slave and make it the candidate
         * for becoming the curr_active_slave
         */
        if (!slave) {
                if (!bond->current_arp_slave) {
                        bond->current_arp_slave = bond->first_slave;
                }

                if (bond->current_arp_slave) {
                        bond_set_slave_inactive_flags(bond->current_arp_slave);

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

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

                                        bond_set_slave_inactive_flags(slave);

                                        printk(KERN_INFO DRV_NAME
                                               ": %s: backup interface %s is "
                                               "now down.\n",
                                               bond_dev->name,
                                               slave->dev->name);
                                }
                        }
                }
        }

re_arm:
        if (bond->params.arp_interval) {
                mod_timer(&bond->arp_timer, jiffies + delta_in_ticks);
        }
out:
        read_unlock(&bond->lock);
}

/*------------------------------ proc/seq_file-------------------------------*/

#ifdef CONFIG_PROC_FS

#define SEQ_START_TOKEN ((void *)1)

static void *bond_info_seq_start(struct seq_file *seq, loff_t *pos)
{
        struct bonding *bond = seq->private;
        loff_t off = 0;
        struct slave *slave;
        int i;

        /* make sure the bond won't be taken away */
        read_lock(&dev_base_lock);
        read_lock_bh(&bond->lock);

        if (*pos == 0) {
                return SEQ_START_TOKEN;
        }

        bond_for_each_slave(bond, slave, i) {
                if (++off == *pos) {
                        return slave;
                }
        }

        return NULL;
}

static void *bond_info_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
        struct bonding *bond = seq->private;
        struct slave *slave = v;

        ++*pos;
        if (v == SEQ_START_TOKEN) {
                return bond->first_slave;
        }

        slave = slave->next;

        return (slave == bond->first_slave) ? NULL : slave;
}

static void bond_info_seq_stop(struct seq_file *seq, void *v)
{
        struct bonding *bond = seq->private;

        read_unlock_bh(&bond->lock);
        read_unlock(&dev_base_lock);
}

static void bond_info_show_master(struct seq_file *seq)
{
        struct bonding *bond = seq->private;
        struct slave *curr;

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

        seq_printf(seq, "Bonding Mode: %s\n",
                   bond_mode_name(bond->params.mode));

        if (USES_PRIMARY(bond->params.mode)) {
                seq_printf(seq, "Primary Slave: %s\n",
                           (bond->params.primary[0]) ?
                                bond->params.primary : "None");

                seq_printf(seq, "Currently Active Slave: %s\n",
                           (curr) ? curr->dev->name : "None");
        }

        seq_printf(seq, "MII Status: %s\n", (curr) ? "up" : "down");
        seq_printf(seq, "MII Polling Interval (ms): %d\n", bond->params.miimon);
        seq_printf(seq, "Up Delay (ms): %d\n",
                   bond->params.updelay * bond->params.miimon);
        seq_printf(seq, "Down Delay (ms): %d\n",
                   bond->params.downdelay * bond->params.miimon);

        if (bond->params.mode == BOND_MODE_8023AD) {
                struct ad_info ad_info;

                seq_puts(seq, "\n802.3ad info\n");
                seq_printf(seq, "LACP rate: %s\n",
                           (bond->params.lacp_fast) ? "fast" : "slow");

                if (bond_3ad_get_active_agg_info(bond, &ad_info)) {
                        seq_printf(seq, "bond %s has no active aggregator\n",
                                   bond->dev->name);
                } else {
                        seq_printf(seq, "Active Aggregator Info:\n");

                        seq_printf(seq, "\tAggregator ID: %d\n",
                                   ad_info.aggregator_id);
                        seq_printf(seq, "\tNumber of ports: %d\n",
                                   ad_info.ports);
                        seq_printf(seq, "\tActor Key: %d\n",
                                   ad_info.actor_key);
                        seq_printf(seq, "\tPartner Key: %d\n",
                                   ad_info.partner_key);
                        seq_printf(seq, "\tPartner Mac Address: %02x:%02x:%02x:%02x:%02x:%02x\n",
                                   ad_info.partner_system[0],
                                   ad_info.partner_system[1],
                                   ad_info.partner_system[2],
                                   ad_info.partner_system[3],
                                   ad_info.partner_system[4],
                                   ad_info.partner_system[5]);
                }
        }
}

static void bond_info_show_slave(struct seq_file *seq, const struct slave *slave)
{
        struct bonding *bond = seq->private;

        seq_printf(seq, "\nSlave Interface: %s\n", slave->dev->name);
        seq_printf(seq, "MII Status: %s\n",
                   (slave->link == BOND_LINK_UP) ?  "up" : "down");
        seq_printf(seq, "Link Failure Count: %d\n",
                   slave->link_failure_count);

        if (app_abi_ver >= 1) {
                seq_printf(seq,
                           "Permanent HW addr: %02x:%02x:%02x:%02x:%02x:%02x\n",
                           slave->perm_hwaddr[0],
                           slave->perm_hwaddr[1],
                           slave->perm_hwaddr[2],
                           slave->perm_hwaddr[3],
                           slave->perm_hwaddr[4],
                           slave->perm_hwaddr[5]);
        }

        if (bond->params.mode == BOND_MODE_8023AD) {
                const struct aggregator *agg
                        = SLAVE_AD_INFO(slave).port.aggregator;

                if (agg) {
                        seq_printf(seq, "Aggregator ID: %d\n",
                                   agg->aggregator_identifier);
                } else {
                        seq_puts(seq, "Aggregator ID: N/A\n");
                }
        }
}

static int bond_info_seq_show(struct seq_file *seq, void *v)
{
        if (v == SEQ_START_TOKEN) {
                seq_printf(seq, "%s\n", version);
                bond_info_show_master(seq);
        } else {
                bond_info_show_slave(seq, v);
        }

        return 0;
}

static struct seq_operations bond_info_seq_ops = {
        .start = bond_info_seq_start,
        .next  = bond_info_seq_next,
        .stop  = bond_info_seq_stop,
        .show  = bond_info_seq_show,
};

static int bond_info_open(struct inode *inode, struct file *file)
{
        struct seq_file *seq;
        struct proc_dir_entry *proc;
        int res;

        res = seq_open(file, &bond_info_seq_ops);
        if (!res) {
                /* recover the pointer buried in proc_dir_entry data */
                seq = file->private_data;
                proc = PDE(inode);
                seq->private = proc->data;
        }

        return res;
}

static struct file_operations bond_info_fops = {
        .owner   = THIS_MODULE,
        .open    = bond_info_open,
        .read    = seq_read,
        .llseek  = seq_lseek,
        .release = seq_release,
};

static int bond_create_proc_entry(struct bonding *bond)
{
        struct net_device *bond_dev = bond->dev;

        if (bond_proc_dir) {
                bond->proc_entry = create_proc_entry(bond_dev->name,
                                                     S_IRUGO,
                                                     bond_proc_dir);
                if (bond->proc_entry == NULL) {
                        printk(KERN_WARNING DRV_NAME
                               ": Warning: Cannot create /proc/net/%s/%s\n",
                               DRV_NAME, bond_dev->name);
                } else {
                        bond->proc_entry->data = bond;
                        bond->proc_entry->proc_fops = &bond_info_fops;
                        bond->proc_entry->owner = THIS_MODULE;
                        memcpy(bond->proc_file_name, bond_dev->name, IFNAMSIZ);
                }
        }

        return 0;
}

static void bond_remove_proc_entry(struct bonding *bond)
{
        if (bond_proc_dir && bond->proc_entry) {
                remove_proc_entry(bond->proc_file_name, bond_proc_dir);
                memset(bond->proc_file_name, 0, IFNAMSIZ);
                bond->proc_entry = NULL;
        }
}

/* Create the bonding directory under /proc/net, if doesn't exist yet.
 * Caller must hold rtnl_lock.
 */
static void bond_create_proc_dir(void)
{
        int len = strlen(DRV_NAME);

        for (bond_proc_dir = proc_net->subdir; bond_proc_dir;
             bond_proc_dir = bond_proc_dir->next) {
                if ((bond_proc_dir->namelen == len) &&
                    !memcmp(bond_proc_dir->name, DRV_NAME, len)) {
                        break;
                }
        }

        if (!bond_proc_dir) {
                bond_proc_dir = proc_mkdir(DRV_NAME, proc_net);
                if (bond_proc_dir) {
                        bond_proc_dir->owner = THIS_MODULE;
                } else {
                        printk(KERN_WARNING DRV_NAME
                                ": Warning: cannot create /proc/net/%s\n",
                                DRV_NAME);
                }
        }
}

/* Destroy the bonding directory under /proc/net, if empty.
 * Caller must hold rtnl_lock.
 */
static void bond_destroy_proc_dir(void)
{
        struct proc_dir_entry *de;

        if (!bond_proc_dir) {
                return;
        }

        /* verify that the /proc dir is empty */
        for (de = bond_proc_dir->subdir; de; de = de->next) {
                /* ignore . and .. */
                if (*(de->name) != '.') {
                        break;
                }
        }

        if (de) {
                if (bond_proc_dir->owner == THIS_MODULE) {
                        bond_proc_dir->owner = NULL;
                }
        } else {
                remove_proc_entry(DRV_NAME, proc_net);
                bond_proc_dir = NULL;
        }
}
#endif /* CONFIG_PROC_FS */

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

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

        return NOTIFY_DONE;
}

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

        switch (event) {
        case NETDEV_CHANGENAME:
                return bond_event_changename(event_bond);
        case NETDEV_UNREGISTER:
                /*
                 * TODO: remove a bond from the list?
                 */
                break;
        default:
                break;
        }

        return NOTIFY_DONE;
}

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

        switch (event) {
        case NETDEV_UNREGISTER:
                if (bond_dev) {
                        bond_release(bond_dev, slave_dev);
                }
                break;
        case NETDEV_CHANGE:
                /*
                 * TODO: is this what we get if somebody
                 * sets up a hierarchical bond, then rmmod's
                 * one of the slave bonding devices?
                 */
                break;
        case NETDEV_DOWN:
                /*
                 * ... Or is it this?
                 */
                break;
        case NETDEV_CHANGEMTU:
                /*
                 * TODO: Should slaves be allowed to
                 * independently alter their MTU?  For
                 * an active-backup bond, slaves need
                 * not be the same type of device, so
                 * MTUs may vary.  For other modes,
                 * slaves arguably should have the
                 * same MTUs. To do this, we'd need to
                 * take over the slave's change_mtu
                 * function for the duration of their
                 * servitude.
                 */
                break;
        case NETDEV_CHANGENAME:
                /*
                 * TODO: handle changing the primary's name
                 */
                break;
        case NETDEV_FEAT_CHANGE:
                bond_compute_features(bond);
                break;
        default:
                break;
        }

        return NOTIFY_DONE;
}

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

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

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

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

        return NOTIFY_DONE;
}

/*
 * bond_inetaddr_event: handle inetaddr notifier chain events.
 *
 * We keep track of device IPs primarily to use as source addresses in
 * ARP monitor probes (rather than spewing out broadcasts all the time).
 *
 * We track one IP for the main device (if it has one), plus one per VLAN.
 */
static int bond_inetaddr_event(struct notifier_block *this, unsigned long event, void *ptr)
{
        struct in_ifaddr *ifa = ptr;
        struct net_device *vlan_dev, *event_dev = ifa->ifa_dev->dev;
        struct bonding *bond, *bond_next;
        struct vlan_entry *vlan, *vlan_next;

        list_for_each_entry_safe(bond, bond_next, &bond_dev_list, bond_list) {
                if (bond->dev == event_dev) {
                        switch (event) {
                        case NETDEV_UP:
                                bond->master_ip = ifa->ifa_local;
                                return NOTIFY_OK;
                        case NETDEV_DOWN:
                                bond->master_ip = bond_glean_dev_ip(bond->dev);
                                return NOTIFY_OK;
                        default:
                                return NOTIFY_DONE;
                        }
                }

                if (list_empty(&bond->vlan_list))
                        continue;

                list_for_each_entry_safe(vlan, vlan_next, &bond->vlan_list,
                                         vlan_list) {
                        vlan_dev = bond->vlgrp->vlan_devices[vlan->vlan_id];
                        if (vlan_dev == event_dev) {
                                switch (event) {
                                case NETDEV_UP:
                                        vlan->vlan_ip = ifa->ifa_local;
                                        return NOTIFY_OK;
                                case NETDEV_DOWN:
                                        vlan->vlan_ip =
                                                bond_glean_dev_ip(vlan_dev);
                                        return NOTIFY_OK;
                                default:
                                        return NOTIFY_DONE;
                                }
                        }
                }
        }
        return NOTIFY_DONE;
}

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

static struct notifier_block bond_inetaddr_notifier = {
        .notifier_call = bond_inetaddr_event,
};

/*-------------------------- Packet type handling ---------------------------*/

/* register to receive lacpdus on a bond */
static void bond_register_lacpdu(struct bonding *bond)
{
        struct packet_type *pk_type = &(BOND_AD_INFO(bond).ad_pkt_type);

        /* initialize packet type */
        pk_type->type = PKT_TYPE_LACPDU;
        pk_type->dev = bond->dev;
        pk_type->func = bond_3ad_lacpdu_recv;

        dev_add_pack(pk_type);
}

/* unregister to receive lacpdus on a bond */
static void bond_unregister_lacpdu(struct bonding *bond)
{
        dev_remove_pack(&(BOND_AD_INFO(bond).ad_pkt_type));
}

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

/*
 * Hash for the the output device based upon layer 3 and layer 4 data. If
 * the packet is a frag or not TCP or UDP, just use layer 3 data.  If it is
 * altogether not IP, mimic bond_xmit_hash_policy_l2()
 */
static int bond_xmit_hash_policy_l34(struct sk_buff *skb,
                                    struct net_device *bond_dev, int count)
{
        struct ethhdr *data = (struct ethhdr *)skb->data;
        struct iphdr *iph = skb->nh.iph;
        u16 *layer4hdr = (u16 *)((u32 *)iph + iph->ihl);
        int layer4_xor = 0;

        if (skb->protocol == __constant_htons(ETH_P_IP)) {
                if (!(iph->frag_off & __constant_htons(IP_MF|IP_OFFSET)) &&
                    (iph->protocol == IPPROTO_TCP ||
                     iph->protocol == IPPROTO_UDP)) {
                        layer4_xor = htons((*layer4hdr ^ *(layer4hdr + 1)));
                }
                return (layer4_xor ^
                        ((ntohl(iph->saddr ^ iph->daddr)) & 0xffff)) % count;

        }

        return (data->h_dest[5] ^ bond_dev->dev_addr[5]) % count;
}

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

        return (data->h_dest[5] ^ bond_dev->dev_addr[5]) % count;
}

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

static int bond_open(struct net_device *bond_dev)
{
        struct bonding *bond = bond_dev->priv;
        struct timer_list *mii_timer = &bond->mii_timer;
        struct timer_list *arp_timer = &bond->arp_timer;

        bond->kill_timers = 0;

        if ((bond->params.mode == BOND_MODE_TLB) ||
            (bond->params.mode == BOND_MODE_ALB)) {
                struct timer_list *alb_timer = &(BOND_ALB_INFO(bond).alb_timer);

                /* bond_alb_initialize must be called before the timer
                 * is started.
                 */
                if (bond_alb_initialize(bond, (bond->params.mode == BOND_MODE_ALB))) {
                        /* something went wrong - fail the open operation */
                        return -1;
                }

                init_timer(alb_timer);
                alb_timer->expires  = jiffies + 1;
                alb_timer->data     = (unsigned long)bond;
                alb_timer->function = (void *)&bond_alb_monitor;
                add_timer(alb_timer);
        }

        if (bond->params.miimon) {  /* link check interval, in milliseconds. */
                init_timer(mii_timer);
                mii_timer->expires  = jiffies + 1;
                mii_timer->data     = (unsigned long)bond_dev;
                mii_timer->function = (void *)&bond_mii_monitor;
                add_timer(mii_timer);
        }

        if (bond->params.arp_interval) {  /* arp interval, in milliseconds. */
                init_timer(arp_timer);
                arp_timer->expires  = jiffies + 1;
                arp_timer->data     = (unsigned long)bond_dev;
                if (bond->params.mode == BOND_MODE_ACTIVEBACKUP) {
                        arp_timer->function = (void *)&bond_activebackup_arp_mon;
                } else {
                        arp_timer->function = (void *)&bond_loadbalance_arp_mon;
                }
                add_timer(arp_timer);
        }

        if (bond->params.mode == BOND_MODE_8023AD) {
                struct timer_list *ad_timer = &(BOND_AD_INFO(bond).ad_timer);
                init_timer(ad_timer);
                ad_timer->expires  = jiffies + 1;
                ad_timer->data     = (unsigned long)bond;
                ad_timer->function = (void *)&bond_3ad_state_machine_handler;
                add_timer(ad_timer);

                /* register to receive LACPDUs */
                bond_register_lacpdu(bond);
        }

        return 0;
}

static int bond_close(struct net_device *bond_dev)
{
        struct bonding *bond = bond_dev->priv;

        if (bond->params.mode == BOND_MODE_8023AD) {
                /* Unregister the receive of LACPDUs */
                bond_unregister_lacpdu(bond);
        }

        write_lock_bh(&bond->lock);

        bond_mc_list_destroy(bond);

        /* signal timers not to re-arm */
        bond->kill_timers = 1;

        write_unlock_bh(&bond->lock);

        /* del_timer_sync must run without holding the bond->lock
         * because a running timer might be trying to hold it too
         */

        if (bond->params.miimon) {  /* link check interval, in milliseconds. */
                del_timer_sync(&bond->mii_timer);
        }

        if (bond->params.arp_interval) {  /* arp interval, in milliseconds. */
                del_timer_sync(&bond->arp_timer);
        }

        switch (bond->params.mode) {
        case BOND_MODE_8023AD:
                del_timer_sync(&(BOND_AD_INFO(bond).ad_timer));
                break;
        case BOND_MODE_TLB:
        case BOND_MODE_ALB:
                del_timer_sync(&(BOND_ALB_INFO(bond).alb_timer));
                break;
        default:
                break;
        }

        /* Release the bonded slaves */
        bond_release_all(bond_dev);

        if ((bond->params.mode == BOND_MODE_TLB) ||
            (bond->params.mode == BOND_MODE_ALB)) {
                /* Must be called only after all
                 * slaves have been released
                 */
                bond_alb_deinitialize(bond);
        }

        return 0;
}

static struct net_device_stats *bond_get_stats(struct net_device *bond_dev)
{
        struct bonding *bond = bond_dev->priv;
        struct net_device_stats *stats = &(bond->stats), *sstats;
        struct slave *slave;
        int i;

        memset(stats, 0, sizeof(struct net_device_stats));

        read_lock_bh(&bond->lock);

        bond_for_each_slave(bond, slave, i) {
                sstats = slave->dev->get_stats(slave->dev);

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

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

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

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

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

        read_unlock_bh(&bond->lock);

        return stats;
}

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

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

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

                if (mii->reg_num == 1) {
                        struct bonding *bond = bond_dev->priv;
                        mii->val_out = 0;
                        read_lock_bh(&bond->lock);
                        read_lock(&bond->curr_slave_lock);
                        if (bond->curr_active_slave) {
                                mii->val_out = BMSR_LSTATUS;
                        }
                        read_unlock(&bond->curr_slave_lock);
                        read_unlock_bh(&bond->lock);
                }

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

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

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

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

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

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

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

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

        if (orig_app_abi_ver == -1) {
                /* no orig_app_abi_ver was provided yet, so we'll use the
                 * current one from now on, even if it's 0
                 */
                orig_app_abi_ver = app_abi_ver;

        } else if (orig_app_abi_ver != app_abi_ver) {
                printk(KERN_ERR DRV_NAME
                       ": Error: already using ifenslave ABI version %d; to "
                       "upgrade ifenslave to version %d, you must first "
                       "reload bonding.\n",
                       orig_app_abi_ver, app_abi_ver);
                return -EINVAL;
        }

        slave_dev = dev_get_by_name(ifr->ifr_slave);

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

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

                dev_put(slave_dev);
        }

        if (res < 0) {
                /* The ioctl failed, so there's no point in changing the
                 * orig_app_abi_ver. We'll restore it's value just in case
                 * we've changed it earlier in this function.
                 */
                orig_app_abi_ver = prev_abi_ver;
        }

        return res;
}

static void bond_set_multicast_list(struct net_device *bond_dev)
{
        struct bonding *bond = bond_dev->priv;
        struct dev_mc_list *dmi;

        write_lock_bh(&bond->lock);

        /*
         * Do promisc before checking multicast_mode
         */
        if ((bond_dev->flags & IFF_PROMISC) && !(bond->flags & IFF_PROMISC)) {
                bond_set_promiscuity(bond, 1);
        }

        if (!(bond_dev->flags & IFF_PROMISC) && (bond->flags & IFF_PROMISC)) {
                bond_set_promiscuity(bond, -1);
        }

        /* set allmulti flag to slaves */
        if ((bond_dev->flags & IFF_ALLMULTI) && !(bond->flags & IFF_ALLMULTI)) {
                bond_set_allmulti(bond, 1);
        }

        if (!(bond_dev->flags & IFF_ALLMULTI) && (bond->flags & IFF_ALLMULTI)) {
                bond_set_allmulti(bond, -1);
        }

        bond->flags = bond_dev->flags;

        /* looking for addresses to add to slaves' mc list */
        for (dmi = bond_dev->mc_list; dmi; dmi = dmi->next) {
                if (!bond_mc_list_find_dmi(dmi, bond->mc_list)) {
                        bond_mc_add(bond, dmi->dmi_addr, dmi->dmi_addrlen);
                }
        }

        /* looking for addresses to delete from slaves' list */
        for (dmi = bond->mc_list; dmi; dmi = dmi->next) {
                if (!bond_mc_list_find_dmi(dmi, bond_dev->mc_list)) {
                        bond_mc_delete(bond, dmi->dmi_addr, dmi->dmi_addrlen);
                }
        }

        /* save master's multicast list */
        bond_mc_list_destroy(bond);
        bond_mc_list_copy(bond_dev->mc_list, bond, GFP_ATOMIC);

        write_unlock_bh(&bond->lock);
}

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

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

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

        bond_for_each_slave(bond, slave, i) {
                dprintk("s %p s->p %p c_m %p\n", slave,
                        slave->prev, slave->dev->change_mtu);
                res = dev_set_mtu(slave->dev, new_mtu);

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

        bond_dev->mtu = new_mtu;

        return 0;

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

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

        return res;
}

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

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

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

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

        bond_for_each_slave(bond, slave, i) {
                dprintk("slave %p %s\n", slave, slave->dev->name);

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

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

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

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

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

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

        return res;
}

static int bond_xmit_roundrobin(struct sk_buff *skb, struct net_device *bond_dev)
{
        struct bonding *bond = bond_dev->priv;
        struct slave *slave, *start_at;
        int i;
        int res = 1;

        read_lock(&bond->lock);

        if (!BOND_IS_OK(bond)) {
                goto out;
        }

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

        if (!slave) {
                goto out;
        }

        bond_for_each_slave_from(bond, slave, i, start_at) {
                if (IS_UP(slave->dev) &&
                    (slave->link == BOND_LINK_UP) &&
                    (slave->state == BOND_STATE_ACTIVE)) {
                        res = bond_dev_queue_xmit(bond, skb, slave->dev);

                        write_lock(&bond->curr_slave_lock);
                        bond->curr_active_slave = slave->next;
                        write_unlock(&bond->curr_slave_lock);

                        break;
                }
        }


out:
        if (res) {
                /* no suitable interface, frame not sent */
                dev_kfree_skb(skb);
        }
        read_unlock(&bond->lock);
        return 0;
}

/*
 * in active-backup mode, we know that bond->curr_active_slave is always valid if
 * the bond has a usable interface.
 */
static int bond_xmit_activebackup(struct sk_buff *skb, struct net_device *bond_dev)
{
        struct bonding *bond = bond_dev->priv;
        int res = 1;

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

        if (!BOND_IS_OK(bond)) {
                goto out;
        }

        if (bond->curr_active_slave) { /* one usable interface */
                res = bond_dev_queue_xmit(bond, skb, bond->curr_active_slave->dev);
        }

out:
        if (res) {
                /* no suitable interface, frame not sent */
                dev_kfree_skb(skb);
        }
        read_unlock(&bond->curr_slave_lock);
        read_unlock(&bond->lock);
        return 0;
}

/*
 * In bond_xmit_xor() , we determine the output device by using a pre-
 * determined xmit_hash_policy(), If the selected device is not enabled,
 * find the next active slave.
 */
static int bond_xmit_xor(struct sk_buff *skb, struct net_device *bond_dev)
{
        struct bonding *bond = bond_dev->priv;
        struct slave *slave, *start_at;
        int slave_no;
        int i;
        int res = 1;

        read_lock(&bond->lock);

        if (!BOND_IS_OK(bond)) {
                goto out;
        }

        slave_no = bond->xmit_hash_policy(skb, bond_dev, bond->slave_cnt);

        bond_for_each_slave(bond, slave, i) {
                slave_no--;
                if (slave_no < 0) {
                        break;
                }
        }

        start_at = slave;

        bond_for_each_slave_from(bond, slave, i, start_at) {
                if (IS_UP(slave->dev) &&
                    (slave->link == BOND_LINK_UP) &&
                    (slave->state == BOND_STATE_ACTIVE)) {
                        res = bond_dev_queue_xmit(bond, skb, slave->dev);
                        break;
                }
        }

out:
        if (res) {
                /* no suitable interface, frame not sent */
                dev_kfree_skb(skb);
        }
        read_unlock(&bond->lock);
        return 0;
}

/*
 * in broadcast mode, we send everything to all usable interfaces.
 */
static int bond_xmit_broadcast(struct sk_buff *skb, struct net_device *bond_dev)
{
        struct bonding *bond = bond_dev->priv;
        struct slave *slave, *start_at;
        struct net_device *tx_dev = NULL;
        int i;
        int res = 1;

        read_lock(&bond->lock);

        if (!BOND_IS_OK(bond)) {
                goto out;
        }

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

        if (!start_at) {
                goto out;
        }

        bond_for_each_slave_from(bond, slave, i, start_at) {
                if (IS_UP(slave->dev) &&
                    (slave->link == BOND_LINK_UP) &&
                    (slave->state == BOND_STATE_ACTIVE)) {
                        if (tx_dev) {
                                struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
                                if (!skb2) {
                                        printk(KERN_ERR DRV_NAME
                                               ": Error: bond_xmit_broadcast(): "
                                               "skb_clone() failed\n");
                                        continue;
                                }

                                res = bond_dev_queue_xmit(bond, skb2, tx_dev);
                                if (res) {
                                        dev_kfree_skb(skb2);
                                        continue;
                                }
                        }
                        tx_dev = slave->dev;
                }
        }

        if (tx_dev) {
                res = bond_dev_queue_xmit(bond, skb, tx_dev);
        }

out:
        if (res) {
                /* no suitable interface, frame not sent */
                dev_kfree_skb(skb);
        }
        /* frame sent to all suitable interfaces */
        read_unlock(&bond->lock);
        return 0;
}

/*------------------------- Device initialization ---------------------------*/

/*
 * set bond mode specific net device operations
 */
static inline void bond_set_mode_ops(struct bonding *bond, int mode)
{
        struct net_device *bond_dev = bond->dev;

        switch (mode) {
        case BOND_MODE_ROUNDROBIN:
                bond_dev->hard_start_xmit = bond_xmit_roundrobin;
                break;
        case BOND_MODE_ACTIVEBACKUP:
                bond_dev->hard_start_xmit = bond_xmit_activebackup;
                break;
        case BOND_MODE_XOR:
                bond_dev->hard_start_xmit = bond_xmit_xor;
                if (bond->params.xmit_policy == BOND_XMIT_POLICY_LAYER34)
                        bond->xmit_hash_policy = bond_xmit_hash_policy_l34;
                else
                        bond->xmit_hash_policy = bond_xmit_hash_policy_l2;
                break;
        case BOND_MODE_BROADCAST:
                bond_dev->hard_start_xmit = bond_xmit_broadcast;
                break;
        case BOND_MODE_8023AD:
                bond_dev->hard_start_xmit = bond_3ad_xmit_xor;
                if (bond->params.xmit_policy == BOND_XMIT_POLICY_LAYER34)
                        bond->xmit_hash_policy = bond_xmit_hash_policy_l34;
                else
                        bond->xmit_hash_policy = bond_xmit_hash_policy_l2;
                break;
        case BOND_MODE_TLB:
        case BOND_MODE_ALB:
                bond_dev->hard_start_xmit = bond_alb_xmit;
                bond_dev->set_mac_address = bond_alb_set_mac_address;
                break;
        default:
                /* Should never happen, mode already checked */
                printk(KERN_ERR DRV_NAME
                       ": Error: Unknown bonding mode %d\n",
                       mode);
                break;
        }
}

static struct ethtool_ops bond_ethtool_ops = {
        .get_tx_csum            = ethtool_op_get_tx_csum,
        .get_sg                 = ethtool_op_get_sg,
};

/*
 * Does not allocate but creates a /proc entry.
 * Allowed to fail.
 */
static int __init bond_init(struct net_device *bond_dev, struct bond_params *params)
{
        struct bonding *bond = bond_dev->priv;

        dprintk("Begin bond_init for %s\n", bond_dev->name);

        /* initialize rwlocks */
        rwlock_init(&bond->lock);
        rwlock_init(&bond->curr_slave_lock);

        bond->params = *params; /* copy params struct */

        /* Initialize pointers */
        bond->first_slave = NULL;
        bond->curr_active_slave = NULL;
        bond->current_arp_slave = NULL;
        bond->primary_slave = NULL;
        bond->dev = bond_dev;
        INIT_LIST_HEAD(&bond->vlan_list);

        /* Initialize the device entry points */
        bond_dev->open = bond_open;
        bond_dev->stop = bond_close;
        bond_dev->get_stats = bond_get_stats;
        bond_dev->do_ioctl = bond_do_ioctl;
        bond_dev->ethtool_ops = &bond_ethtool_ops;
        bond_dev->set_multicast_list = bond_set_multicast_list;
        bond_dev->change_mtu = bond_change_mtu;
        bond_dev->set_mac_address = bond_set_mac_address;

        bond_set_mode_ops(bond, bond->params.mode);

        bond_dev->destructor = free_netdev;

        /* Initialize the device options */
        bond_dev->tx_queue_len = 0;
        bond_dev->flags |= IFF_MASTER|IFF_MULTICAST;

        /* At first, we block adding VLANs. That's the only way to
         * prevent problems that occur when adding VLANs over an
         * empty bond. The block will be removed once non-challenged
         * slaves are enslaved.
         */
        bond_dev->features |= NETIF_F_VLAN_CHALLENGED;

        /* don't acquire bond device's xmit_lock when 
         * transmitting */
        bond_dev->features |= NETIF_F_LLTX;

        /* By default, we declare the bond to be fully
         * VLAN hardware accelerated capable. Special
         * care is taken in the various xmit functions
         * when there are slaves that are not hw accel
         * capable
         */
        bond_dev->vlan_rx_register = bond_vlan_rx_register;
        bond_dev->vlan_rx_add_vid  = bond_vlan_rx_add_vid;
        bond_dev->vlan_rx_kill_vid = bond_vlan_rx_kill_vid;
        bond_dev->features |= (NETIF_F_HW_VLAN_TX |
                               NETIF_F_HW_VLAN_RX |
                               NETIF_F_HW_VLAN_FILTER);

        bond->bond_features = bond_dev->features;

#ifdef CONFIG_PROC_FS
        bond_create_proc_entry(bond);
#endif

        list_add_tail(&bond->bond_list, &bond_dev_list);

        return 0;
}

/* De-initialize device specific data.
 * Caller must hold rtnl_lock.
 */
static inline void bond_deinit(struct net_device *bond_dev)
{
        struct bonding *bond = bond_dev->priv;

        list_del(&bond->bond_list);

#ifdef CONFIG_PROC_FS
        bond_remove_proc_entry(bond);
#endif
}

/* Unregister and free all bond devices.
 * Caller must hold rtnl_lock.
 */
static void bond_free_all(void)
{
        struct bonding *bond, *nxt;

        list_for_each_entry_safe(bond, nxt, &bond_dev_list, bond_list) {
                struct net_device *bond_dev = bond->dev;

                unregister_netdevice(bond_dev);
                bond_deinit(bond_dev);
        }

#ifdef CONFIG_PROC_FS
        bond_destroy_proc_dir();
#endif
}

/*------------------------- Module initialization ---------------------------*/

/*
 * Convert string input module parms.  Accept either the
 * number of the mode or its string name.
 */
static inline int bond_parse_parm(char *mode_arg, struct bond_parm_tbl *tbl)
{
        int i;

        for (i = 0; tbl[i].modename; i++) {
                if ((isdigit(*mode_arg) &&
                     tbl[i].mode == simple_strtol(mode_arg, NULL, 0)) ||
                    (strncmp(mode_arg, tbl[i].modename,
                             strlen(tbl[i].modename)) == 0)) {
                        return tbl[i].mode;
                }
        }

        return -1;
}

static int bond_check_params(struct bond_params *params)
{
        /*
         * Convert string parameters.
         */
        if (mode) {
                bond_mode = bond_parse_parm(mode, bond_mode_tbl);
                if (bond_mode == -1) {
                        printk(KERN_ERR DRV_NAME
                               ": Error: Invalid bonding mode \"%s\"\n",
                               mode == NULL ? "NULL" : mode);
                        return -EINVAL;
                }
        }

        if (xmit_hash_policy) {
                if ((bond_mode != BOND_MODE_XOR) &&
                    (bond_mode != BOND_MODE_8023AD)) {
                        printk(KERN_INFO DRV_NAME
                               ": xor_mode param is irrelevant in mode %s\n",
                               bond_mode_name(bond_mode));
                } else {
                        xmit_hashtype = bond_parse_parm(xmit_hash_policy,
                                                        xmit_hashtype_tbl);
                        if (xmit_hashtype == -1) {
                                printk(KERN_ERR DRV_NAME
                                ": Error: Invalid xmit_hash_policy \"%s\"\n",
                                xmit_hash_policy == NULL ? "NULL" :
                                       xmit_hash_policy);
                                return -EINVAL;
                        }
                }
        }

        if (lacp_rate) {
                if (bond_mode != BOND_MODE_8023AD) {
                        printk(KERN_INFO DRV_NAME
                               ": lacp_rate param is irrelevant in mode %s\n",
                               bond_mode_name(bond_mode));
                } else {
                        lacp_fast = bond_parse_parm(lacp_rate, bond_lacp_tbl);
                        if (lacp_fast == -1) {
                                printk(KERN_ERR DRV_NAME
                                       ": Error: Invalid lacp rate \"%s\"\n",
                                       lacp_rate == NULL ? "NULL" : lacp_rate);
                                return -EINVAL;
                        }
                }
        }

        if (max_bonds < 1 || max_bonds > INT_MAX) {
                printk(KERN_WARNING DRV_NAME
                       ": Warning: max_bonds (%d) not in range %d-%d, so it "
                       "was reset to BOND_DEFAULT_MAX_BONDS (%d)",
                       max_bonds, 1, INT_MAX, BOND_DEFAULT_MAX_BONDS);
                max_bonds = BOND_DEFAULT_MAX_BONDS;
        }

        if (miimon < 0) {
                printk(KERN_WARNING DRV_NAME
                       ": Warning: miimon module parameter (%d), "
                       "not in range 0-%d, so it was reset to %d\n",
                       miimon, INT_MAX, BOND_LINK_MON_INTERV);
                miimon = BOND_LINK_MON_INTERV;
        }

        if (updelay < 0) {
                printk(KERN_WARNING DRV_NAME
                       ": Warning: updelay module parameter (%d), "
                       "not in range 0-%d, so it was reset to 0\n",
                       updelay, INT_MAX);
                updelay = 0;
        }

        if (downdelay < 0) {
                printk(KERN_WARNING DRV_NAME
                       ": Warning: downdelay module parameter (%d), "
                       "not in range 0-%d, so it was reset to 0\n",
                       downdelay, INT_MAX);
                downdelay = 0;
        }

        if ((use_carrier != 0) && (use_carrier != 1)) {
                printk(KERN_WARNING DRV_NAME
                       ": Warning: use_carrier module parameter (%d), "
                       "not of valid value (0/1), so it was set to 1\n",
                       use_carrier);
                use_carrier = 1;
        }

        /* reset values for 802.3ad */
        if (bond_mode == BOND_MODE_8023AD) {
                if (!miimon) {
                        printk(KERN_WARNING DRV_NAME
                               ": Warning: miimon must be specified, "
                               "otherwise bonding will not detect link "
                               "failure, speed and duplex which are "
                               "essential for 802.3ad operation\n");
                        printk(KERN_WARNING "Forcing miimon to 100msec\n");
                        miimon = 100;
                }
        }

        /* reset values for TLB/ALB */
        if ((bond_mode == BOND_MODE_TLB) ||
            (bond_mode == BOND_MODE_ALB)) {
                if (!miimon) {
                        printk(KERN_WARNING DRV_NAME
                               ": Warning: miimon must be specified, "
                               "otherwise bonding will not detect link "
                               "failure and link speed which are essential "
                               "for TLB/ALB load balancing\n");
                        printk(KERN_WARNING "Forcing miimon to 100msec\n");
                        miimon = 100;
                }
        }

        if (bond_mode == BOND_MODE_ALB) {
                printk(KERN_NOTICE DRV_NAME
                       ": In ALB mode you might experience client "
                       "disconnections upon reconnection of a link if the "
                       "bonding module updelay parameter (%d msec) is "
                       "incompatible with the forwarding delay time of the "
                       "switch\n",
                       updelay);
        }

        if (!miimon) {
                if (updelay || downdelay) {
                        /* just warn the user the up/down delay will have
                         * no effect since miimon is zero...
                         */
                        printk(KERN_WARNING DRV_NAME
                               ": Warning: miimon module parameter not set "
                               "and updelay (%d) or downdelay (%d) module "
                               "parameter is set; updelay and downdelay have "
                               "no effect unless miimon is set\n",
                               updelay, downdelay);
                }
        } else {
                /* don't allow arp monitoring */
                if (arp_interval) {
                        printk(KERN_WARNING DRV_NAME
                               ": Warning: miimon (%d) and arp_interval (%d) "
                               "can't be used simultaneously, disabling ARP "
                               "monitoring\n",
                               miimon, arp_interval);
                        arp_interval = 0;
                }

                if ((updelay % miimon) != 0) {
                        printk(KERN_WARNING DRV_NAME
                               ": Warning: updelay (%d) is not a multiple "
                               "of miimon (%d), updelay rounded to %d ms\n",
                               updelay, miimon, (updelay / miimon) * miimon);
                }

                updelay /= miimon;

                if ((downdelay % miimon) != 0) {
                        printk(KERN_WARNING DRV_NAME
                               ": Warning: downdelay (%d) is not a multiple "
                               "of miimon (%d), downdelay rounded to %d ms\n",
                               downdelay, miimon,
                               (downdelay / miimon) * miimon);
                }

                downdelay /= miimon;
        }

        if (arp_interval < 0) {
                printk(KERN_WARNING DRV_NAME
                       ": Warning: arp_interval module parameter (%d) "
                       ", not in range 0-%d, so it was reset to %d\n",
                       arp_interval, INT_MAX, BOND_LINK_ARP_INTERV);
                arp_interval = BOND_LINK_ARP_INTERV;
        }

        for (arp_ip_count = 0;
             (arp_ip_count < BOND_MAX_ARP_TARGETS) && arp_ip_target[arp_ip_count];
             arp_ip_count++) {
                /* not complete check, but should be good enough to
                   catch mistakes */
                if (!isdigit(arp_ip_target[arp_ip_count][0])) {
                        printk(KERN_WARNING DRV_NAME
                               ": Warning: bad arp_ip_target module parameter "
                               "(%s), ARP monitoring will not be performed\n",
                               arp_ip_target[arp_ip_count]);
                        arp_interval = 0;
                } else {
                        u32 ip = in_aton(arp_ip_target[arp_ip_count]);
                        arp_target[arp_ip_count] = ip;
                }
        }

        if (arp_interval && !arp_ip_count) {
                /* don't allow arping if no arp_ip_target given... */
                printk(KERN_WARNING DRV_NAME
                       ": Warning: arp_interval module parameter (%d) "
                       "specified without providing an arp_ip_target "
                       "parameter, arp_interval was reset to 0\n",
                       arp_interval);
                arp_interval = 0;
        }

        if (miimon) {
                printk(KERN_INFO DRV_NAME
                       ": MII link monitoring set to %d ms\n",
                       miimon);
        } else if (arp_interval) {
                int i;

                printk(KERN_INFO DRV_NAME
                       ": ARP monitoring set to %d ms with %d target(s):",
                       arp_interval, arp_ip_count);

                for (i = 0; i < arp_ip_count; i++)
                        printk (" %s", arp_ip_target[i]);

                printk("\n");

        } else {
                /* miimon and arp_interval not set, we need one so things
                 * work as expected, see bonding.txt for details
                 */
                printk(KERN_WARNING DRV_NAME
                       ": Warning: either miimon or arp_interval and "
                       "arp_ip_target module parameters must be specified, "
                       "otherwise bonding will not detect link failures! see "
                       "bonding.txt for details.\n");
        }

        if (primary && !USES_PRIMARY(bond_mode)) {
                /* currently, using a primary only makes sense
                 * in active backup, TLB or ALB modes
                 */
                printk(KERN_WARNING DRV_NAME
                       ": Warning: %s primary device specified but has no "
                       "effect in %s mode\n",
                       primary, bond_mode_name(bond_mode));
                primary = NULL;
        }

        /* fill params struct with the proper values */
        params->mode = bond_mode;
        params->xmit_policy = xmit_hashtype;
        params->miimon = miimon;
        params->arp_interval = arp_interval;
        params->updelay = updelay;
        params->downdelay = downdelay;
        params->use_carrier = use_carrier;
        params->lacp_fast = lacp_fast;
        params->primary[0] = 0;

        if (primary) {
                strncpy(params->primary, primary, IFNAMSIZ);
                params->primary[IFNAMSIZ - 1] = 0;
        }

        memcpy(params->arp_targets, arp_target, sizeof(arp_target));

        return 0;
}

static int __init bonding_init(void)
{
        struct bond_params params;
        int i;
        int res;

        printk(KERN_INFO "%s", version);

        res = bond_check_params(&params);
        if (res) {
                return res;
        }

        rtnl_lock();

#ifdef CONFIG_PROC_FS
        bond_create_proc_dir();
#endif

        for (i = 0; i < max_bonds; i++) {
                struct net_device *bond_dev;

                bond_dev = alloc_netdev(sizeof(struct bonding), "", ether_setup);
                if (!bond_dev) {
                        res = -ENOMEM;
                        goto out_err;
                }

                res = dev_alloc_name(bond_dev, "bond%d");
                if (res < 0) {
                        free_netdev(bond_dev);
                        goto out_err;
                }

                /* bond_init() must be called after dev_alloc_name() (for the
                 * /proc files), but before register_netdevice(), because we
                 * need to set function pointers.
                 */
                res = bond_init(bond_dev, &params);
                if (res < 0) {
                        free_netdev(bond_dev);
                        goto out_err;
                }

                SET_MODULE_OWNER(bond_dev);

                res = register_netdevice(bond_dev);
                if (res < 0) {
                        bond_deinit(bond_dev);
                        free_netdev(bond_dev);
                        goto out_err;
                }
        }

        rtnl_unlock();
        register_netdevice_notifier(&bond_netdev_notifier);
        register_inetaddr_notifier(&bond_inetaddr_notifier);

        return 0;

out_err:
        /*
         * rtnl_unlock() will run netdev_run_todo(), putting the
         * thus-far-registered bonding devices into a state which
         * unregigister_netdevice() will accept
         */
        rtnl_unlock();
        rtnl_lock();

        /* free and unregister all bonds that were successfully added */
        bond_free_all();

        rtnl_unlock();

        return res;
}

static void __exit bonding_exit(void)
{
        unregister_netdevice_notifier(&bond_netdev_notifier);
        unregister_inetaddr_notifier(&bond_inetaddr_notifier);

        rtnl_lock();
        bond_free_all();
        rtnl_unlock();
}

module_init(bonding_init);
module_exit(bonding_exit);
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);
MODULE_DESCRIPTION(DRV_DESCRIPTION ", v" DRV_VERSION);
MODULE_AUTHOR("Thomas Davis, tadavis@lbl.gov and many others");
MODULE_SUPPORTED_DEVICE("most ethernet devices");

/*
 * Local variables:
 *  c-indent-level: 8
 *  c-basic-offset: 8
 *  tab-width: 8
 * End:
 */