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/*
 * Equalizer Load-balancer for serial network interfaces.
 *
 * (c) Copyright 1995 Simon "Guru Aleph-Null" Janes
 * NCM: Network and Communications Management, Inc.
 *
 *
 *      This software may be used and distributed according to the terms
 *      of the GNU Public License, incorporated herein by reference.
 *
 * The author may be reached as simon@ncm.com, or C/O
 *    NCM
 *    Attn: Simon Janes
 *    6803 Whittier Ave
 *    McLean VA 22101
 *    Phone: 1-703-847-0040 ext 103
 */
 
static const char *version =
        "Equalizer1996: $Revision: 1.1 $ $Date: 2005-12-20 10:17:14 $ Simon Janes (simon@ncm.com)\n";
 
/*
 * Sources:
 *   skeleton.c by Donald Becker.
 * Inspirations:
 *   The Harried and Overworked Alan Cox
 * Conspiracies:
 *   The Alan Cox and Mike McLagan plot to get someone else to do the code,
 *   which turned out to be me.
 */
 
/*
 * $Log: not supported by cvs2svn $
 * Revision 1.1.1.1  2001/09/10 07:44:23  simons
 * Initial import
 *
 * Revision 1.1.1.1  2001/07/02 17:58:23  simons
 * Initial revision
 *
 * Revision 1.9  1996/10/12 11:14:37  davem
 * Quick merge to 2.0.20
 *
 * Revision 1.2  1996/04/11 17:51:52  guru
 * Added one-line eql_remove_slave patch.
 *
 * Revision 1.1  1996/04/11 17:44:17  guru
 * Initial revision
 *
 * Revision 3.13  1996/01/21  15:17:18  alan
 * tx_queue_len changes.
 * reformatted.
 *
 * Revision 3.12  1995/03/22  21:07:51  anarchy
 * Added suser() checks on configuration.
 * Moved header file.
 *
 * Revision 3.11  1995/01/19  23:14:31  guru
 *                    slave_load = (ULONG_MAX - (ULONG_MAX / 2)) -
 *                      (priority_Bps) + bytes_queued * 8;
 *
 * Revision 3.10  1995/01/19  23:07:53  guru
 * back to
 *                    slave_load = (ULONG_MAX - (ULONG_MAX / 2)) -
 *                      (priority_Bps) + bytes_queued;
 *
 * Revision 3.9  1995/01/19  22:38:20  guru
 *                    slave_load = (ULONG_MAX - (ULONG_MAX / 2)) -
 *                      (priority_Bps) + bytes_queued * 4;
 *
 * Revision 3.8  1995/01/19  22:30:55  guru
 *       slave_load = (ULONG_MAX - (ULONG_MAX / 2)) -
 *                      (priority_Bps) + bytes_queued * 2;
 *
 * Revision 3.7  1995/01/19  21:52:35  guru
 * printk's trimmed out.
 *
 * Revision 3.6  1995/01/19  21:49:56  guru
 * This is working pretty well. I gained 1 K/s in speed.. now it's just
 * robustness and printk's to be diked out.
 *
 * Revision 3.5  1995/01/18  22:29:59  guru
 * still crashes the kernel when the lock_wait thing is woken up.
 *
 * Revision 3.4  1995/01/18  21:59:47  guru
 * Broken set-bit locking snapshot
 *
 * Revision 3.3  1995/01/17  22:09:18  guru
 * infinite sleep in a lock somewhere..
 *
 * Revision 3.2  1995/01/15  16:46:06  guru
 * Log trimmed of non-pertinent 1.x branch messages
 *
 * Revision 3.1  1995/01/15  14:41:45  guru
 * New Scheduler and timer stuff...
 *
 * Revision 1.15  1995/01/15  14:29:02  guru
 * Will make 1.14 (now 1.15) the 3.0 branch, and the 1.12 the 2.0 branch, the one
 * with the dumber scheduler
 *
 * Revision 1.14  1995/01/15  02:37:08  guru
 * shock.. the kept-new-versions could have zonked working
 * stuff.. shudder
 *
 * Revision 1.13  1995/01/15  02:36:31  guru
 * big changes
 *
 *      scheduler was torn out and replaced with something smarter
 *
 *      global names not prefixed with eql_ were renamed to protect
 *      against namespace collisions
 *
 *      a few more abstract interfaces were added to facilitate any
 *      potential change of datastructure.  the driver is still using
 *      a linked list of slaves.  going to a heap would be a bit of
 *      an overkill.
 *
 *      this compiles fine with no warnings.
 *
 *      the locking mechanism and timer stuff must be written however,
 *      this version will not work otherwise
 *
 */
 
#include <linux/module.h>
 
#include <linux/kernel.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 <linux/malloc.h>
#include <linux/string.h>
#include <asm/system.h>
#include <asm/bitops.h>
#include <asm/io.h>
#include <asm/dma.h>
#include <linux/errno.h>              
 
#include <linux/netdevice.h>
#include <linux/if.h>
#include <linux/if_arp.h>
#include <linux/timer.h>
 
#include <linux/if_eql.h>
 
#ifndef EQL_DEBUG
/* #undef EQL_DEBUG      -* print nothing at all, not even a boot-banner */
/* #define EQL_DEBUG 1   -* print only the boot-banner */
/* #define EQL_DEBUG 5   -* print major function entries */
/* #define EQL_DEBUG 20  -* print subfunction entries */
/* #define EQL_DEBUG 50  -* print utility entries */
/* #define EQL_DEBUG 100 -* print voluminous function entries */
#define EQL_DEBUG 1
#endif
static unsigned int eql_debug = EQL_DEBUG;
 
int        eql_init(struct device *dev); /*  */
static int eql_open(struct device *dev); /*  */
static int eql_close(struct device *dev); /*  */
static int eql_ioctl(struct device *dev, struct ifreq *ifr, int cmd); /*  */
static int eql_slave_xmit(struct sk_buff *skb, struct device *dev); /*  */
 
static struct enet_statistics *eql_get_stats(struct device *dev); /*  */
static int eql_header(struct sk_buff *skb, struct device *dev,
                      unsigned short type, void *daddr, void *saddr,
                      unsigned len); /*  */
static int eql_rebuild_header(void *buff, struct device *dev,
                              unsigned long raddr, struct sk_buff *skb); /*  */
 
/* ioctl() handlers
   ---------------- */
static int eql_enslave(struct device *dev,  slaving_request_t *srq); /*  */
static int eql_emancipate(struct device *dev, slaving_request_t *srq); /*  */
 
static int eql_g_slave_cfg(struct device *dev, slave_config_t *sc); /*  */
static int eql_s_slave_cfg(struct device *dev, slave_config_t *sc); /*  */
 
static int eql_g_master_cfg(struct device *dev, master_config_t *mc); /*  */
static int eql_s_master_cfg(struct device *dev, master_config_t *mc); /*  */
 
static inline int eql_is_slave(struct device *dev); /*  */
static inline int eql_is_master(struct device *dev); /*  */
 
static slave_t *eql_new_slave(void); /*  */
static void eql_delete_slave(slave_t *slave); /*  */
 
/* static long eql_slave_priority(slave_t *slave); -*  */
static inline int eql_number_slaves(slave_queue_t *queue); /*  */
 
static inline int eql_is_empty(slave_queue_t *queue); /*  */
static inline int eql_is_full(slave_queue_t *queue); /*  */
 
static slave_queue_t *eql_new_slave_queue(struct device *dev); /*  */
static void eql_delete_slave_queue(slave_queue_t *queue); /*  */
 
static int eql_insert_slave(slave_queue_t *queue, slave_t *slave); /*  */
static slave_t *eql_remove_slave(slave_queue_t *queue, slave_t *slave); /*  */
 
/* static int eql_insert_slave_dev(slave_queue_t *queue, struct device *dev); -*  */
static int eql_remove_slave_dev(slave_queue_t *queue, struct device *dev); /*  */
 
static inline struct device *eql_best_slave_dev(slave_queue_t *queue); /*  */
static inline slave_t *eql_best_slave(slave_queue_t *queue); /*  */
static inline slave_t *eql_first_slave(slave_queue_t *queue); /*  */
static inline slave_t *eql_next_slave(slave_queue_t *queue, slave_t *slave); /*  */
 
static inline void eql_set_best_slave(slave_queue_t *queue, slave_t *slave); /*  */
static inline void eql_schedule_slaves(slave_queue_t *queue); /*  */
 
static slave_t *eql_find_slave_dev(slave_queue_t *queue, struct device *dev); /*  */
 
/* static inline eql_lock_slave_queue(slave_queue_t *queue); -*  */
/* static inline eql_unlock_slave_queue(slave_queue_t *queue); -*  */
 
static void eql_timer(unsigned long param);     /*  */
 
/* struct device * interface functions
   ---------------------------------------------------------
   */
 
int eql_init(struct device *dev)
{
        static unsigned version_printed = 0;
        /* static unsigned num_masters     = 0; */
        equalizer_t *eql = 0;
        int i;
 
        if ( version_printed++ == 0 && eql_debug > 0)
                printk(version);
        /*
         *      Initialize the device structure.
         */
        dev->priv = kmalloc (sizeof (equalizer_t), GFP_KERNEL);
        if (dev->priv == NULL)
                return -ENOMEM;
        memset (dev->priv, 0, sizeof (equalizer_t));
        eql = (equalizer_t *) dev->priv;
 
        eql->stats = kmalloc (sizeof (struct enet_statistics), GFP_KERNEL);
        if (eql->stats == NULL)
        {
                kfree(dev->priv);
                dev->priv = NULL;
                return -ENOMEM;
        }
        memset (eql->stats, 0, sizeof (struct enet_statistics));
 
        init_timer (&eql->timer);
        eql->timer.data         = (unsigned long) dev->priv;
        eql->timer.expires      = jiffies+EQL_DEFAULT_RESCHED_IVAL;
        eql->timer.function     = &eql_timer;
        eql->timer_on           = 0;
 
        dev->open               = eql_open;
        dev->stop               = eql_close;
        dev->do_ioctl           = eql_ioctl;
        dev->hard_start_xmit    = eql_slave_xmit;
        dev->get_stats          = eql_get_stats;
 
        /*
         *      Fill in the fields of the device structure with
         *      eql-generic values. This should be in a common
         *      file instead of per-driver.
         */
 
        for (i = 0; i < DEV_NUMBUFFS; i++)
                skb_queue_head_init(&dev->buffs[i]);
 
        dev->hard_header        = eql_header;
        dev->rebuild_header     = eql_rebuild_header;
        dev->hard_header_len    = MAX_HEADER; /* enough space for any slave */
 
        /*
         *      Now we undo some of the things that eth_setup does
         *      that we don't like
         */
 
        dev->mtu                = EQL_DEFAULT_MTU;      /* set to 576 in eql.h */
        dev->flags              = IFF_MASTER;
 
        dev->family             = AF_INET;
        dev->pa_addr            = 0;
        dev->pa_brdaddr         = 0;
        dev->pa_mask            = 0;
        dev->pa_alen            = 4;
 
        dev->type               = ARPHRD_SLIP;
        dev->tx_queue_len       = 5;            /* Hands them off fast */
 
        return 0;
}
 
static int eql_open(struct device *dev)
{
        equalizer_t *eql = (equalizer_t *) dev->priv;
        slave_queue_t *new_queue;
 
#ifdef EQL_DEBUG
        if (eql_debug >= 5)
                printk ("%s: open\n", dev->name);
#endif
 
        printk ("%s: remember to turn off Van-Jacobson compression on your slave devices.\n", dev->name);
 
        new_queue = eql_new_slave_queue (dev);
 
        if (new_queue != 0)
        {
                new_queue->master_dev = dev;
                eql->queue = new_queue;
                eql->queue->lock = 0;
                eql->min_slaves = 1;
                eql->max_slaves = EQL_DEFAULT_MAX_SLAVES; /* 4 usually... */
 
                printk ("%s: adding timer\n", dev->name);
                eql->timer_on = 1;
                add_timer (&eql->timer);
 
                MOD_INC_USE_COUNT;
                return 0;
        }
        return 1;
}
 
 
static int eql_close(struct device *dev)
{
        equalizer_t *eql = (equalizer_t *) dev->priv;
 
#ifdef EQL_DEBUG
        if ( eql_debug >= 5)
                printk ("%s: close\n", dev->name);
#endif
        /*
         *      The timer has to be stopped first before we start hacking away
         *      at the data structure it scans every so often...
         */
 
#ifdef EQL_DEBUG
        printk ("%s: stopping timer\n", dev->name);
#endif  
        eql->timer_on = 0;
        del_timer (&eql->timer);
 
        eql_delete_slave_queue (eql->queue);
 
        MOD_DEC_USE_COUNT;
        return 0;
}
 
 
static int eql_ioctl(struct device *dev, struct ifreq *ifr, int cmd)
{
        if(!suser() && cmd!=EQL_GETMASTRCFG && cmd!=EQL_GETSLAVECFG)
                return -EPERM;
        switch (cmd)
        {
                case EQL_ENSLAVE:
                        return eql_enslave (dev, (slaving_request_t *) ifr->ifr_data);
                case EQL_EMANCIPATE:
                        return eql_emancipate (dev, (slaving_request_t *) ifr->ifr_data);
                case EQL_GETSLAVECFG:
                        return eql_g_slave_cfg (dev, (slave_config_t *) ifr->ifr_data);
                case EQL_SETSLAVECFG:
                        return eql_s_slave_cfg (dev, (slave_config_t *) ifr->ifr_data);
                case EQL_GETMASTRCFG:
                        return eql_g_master_cfg (dev, (master_config_t *) ifr->ifr_data);
                case EQL_SETMASTRCFG:
                        return eql_s_master_cfg (dev, (master_config_t *) ifr->ifr_data);
                default:
                        return -EOPNOTSUPP;
        }
}
 
 
static int eql_slave_xmit(struct sk_buff *skb, struct device *dev)
{
        equalizer_t *eql = (equalizer_t *) dev->priv;
        struct device *slave_dev = 0;
        slave_t *slave;
 
        if (skb == NULL)
                return 0;
 
#if 0
        /* Make a copy we can free so we don't mess up the skb->dev pointer */
        skb2 = skb_clone(skb, GFP_ATOMIC);
 
        if (skb2 == NULL)
                return 1;
#endif
 
        eql_schedule_slaves (eql->queue);
 
        slave = eql_best_slave (eql->queue);
        slave_dev = slave ? slave->dev : 0;
 
        if ( slave_dev != 0 )
        {
#ifdef EQL_DEBUG
                if (eql_debug >= 100)
                        printk ("%s: %d slaves xmitng %ld B %s\n",
                                dev->name, eql_number_slaves (eql->queue), skb->len,
                                slave_dev->name);
#endif
 
                /* Rip off the fake header */
                skb_pull(skb,MAX_HEADER);
 
                /* The original code had no hard header constructed.
                 * If a frame is fragmented on EQL and then passed to PPP,
                 * or ISDN, the result will be a panic.
                 * The solution is to call the hard_header constructor
                 * for the device we point to just before we send the packet.
                 * If this fails we drop the packet.
                 * We don't know any special parameters for the hard_header
                 * constructor at this point, so we pass in made up values
                 * that will cause the constructor to fail on every device
                 * except those that we are allowed to use EQL on:
                 * PPP, SLIP and ISDN (in some cases!).
                 * The worst thing that happens is if some fool
                 * configures EQL to enslave something that needs
                 * these parameters it throws out packets.
                 * This is not an issue for the things EQL is intended for
                 * anyway, and probably would have crashed the kernel
                 * or sent garbage down the wire previously.
                 */
 
                if (slave_dev->hard_header == NULL
                || slave_dev->hard_header(skb,slave_dev,
                        ETH_P_IP,NULL,NULL,skb->len) >= 0) {
                        slave->bytes_queued += skb->len;
                        dev_queue_xmit (skb, slave_dev, 1);
                        eql->stats->tx_packets++;
                        /* dev_kfree_skb(skb, FREE_WRITE); */
                        return 0;
                }
        }
 
        /*
         *      The alternative for this is the return 1 and have
         *      dev_queue_xmit just queue it up on the eql's queue.
         */
 
        eql->stats->tx_dropped++;
        /* dev_kfree_skb(skb2, FREE_WRITE); */
        dev_kfree_skb(skb, FREE_WRITE);
        return 0;
}
 
 
static struct enet_statistics * eql_get_stats(struct device *dev)
{
        equalizer_t *eql = (equalizer_t *) dev->priv;
        return eql->stats;
}
 
 
static int  eql_header(struct sk_buff *skb, struct device *dev,
           unsigned short type, void *daddr, void *saddr,
           unsigned len)
{
        /* Fake header to keep space during buggy IP fragmentation.  */
        skb_push(skb,MAX_HEADER);
        return MAX_HEADER;
}
 
 
static int eql_rebuild_header(void *buff, struct device *dev,
                   unsigned long raddr, struct sk_buff *skb)
{
        return 0;
}
 
/*
 *      Private ioctl functions
 */
 
static int eql_enslave(struct device *dev, slaving_request_t *srqp)
{
        struct device *master_dev;
        struct device *slave_dev;
        slaving_request_t srq;
        int err;
 
        err = verify_area(VERIFY_READ, (void *)srqp, sizeof (slaving_request_t));
        if (err)
          {
#ifdef EQL_DEBUG
        if (eql_debug >= 20)
                printk ("EQL enslave: error detected by verify_area\n");
#endif  
                return err;
          }
        memcpy_fromfs (&srq, srqp, sizeof (slaving_request_t));
 
#ifdef EQL_DEBUG
        if (eql_debug >= 20)
                printk ("%s: enslave '%s' %ld bps\n", dev->name,
                        srq.slave_name, srq.priority);
#endif  
        master_dev = dev;               /* for "clarity" */
        slave_dev  = dev_get (srq.slave_name);
 
        if (master_dev != 0 && slave_dev != 0)
        {
                if ((master_dev->flags & IFF_UP) == IFF_UP)
                {
                        /*slave is not a master & not already a slave:*/
                        if (! eql_is_master (slave_dev)  &&
                            ! eql_is_slave (slave_dev) )
                        {
                                slave_t *s = eql_new_slave ();
                                equalizer_t *eql =
                                        (equalizer_t *) master_dev->priv;
                                s->dev = slave_dev;
                                s->priority = srq.priority;
                                s->priority_bps = srq.priority;
                                s->priority_Bps = srq.priority / 8;
                                slave_dev->flags |= IFF_SLAVE;
                                eql_insert_slave (eql->queue, s);
                                return 0;
                        }
#ifdef EQL_DEBUG
                        else if (eql_debug >= 20)
                                printk ("EQL enslave: slave is master or slave is already slave\n");
#endif  
                }
#ifdef EQL_DEBUG
                else if (eql_debug >= 20)
                        printk ("EQL enslave: master device not up!\n");
#endif  
        }
#ifdef EQL_DEBUG
        else if (eql_debug >= 20)
                printk ("EQL enslave: master or slave are NULL");
#endif  
        return -EINVAL;
}
 
static int eql_emancipate(struct device *dev, slaving_request_t *srqp)
{
        struct device *master_dev;
        struct device *slave_dev;
        slaving_request_t srq;
        int err;
 
        err = verify_area(VERIFY_READ, (void *)srqp, sizeof (slaving_request_t));
        if (err)
                return err;
 
        memcpy_fromfs (&srq, srqp, sizeof (slaving_request_t));
#ifdef EQL_DEBUG
        if (eql_debug >= 20)
                printk ("%s: emancipate `%s`\n", dev->name, srq.slave_name);
#endif
        master_dev = dev;               /* for "clarity" */
        slave_dev  = dev_get (srq.slave_name);
 
        if ( eql_is_slave (slave_dev) ) /* really is a slave */
        {
                equalizer_t *eql = (equalizer_t *) master_dev->priv;
                slave_dev->flags = slave_dev->flags & ~IFF_SLAVE;
                eql_remove_slave_dev (eql->queue, slave_dev);
                return 0;
        }
        return -EINVAL;
}
 
 
static int eql_g_slave_cfg(struct device *dev, slave_config_t *scp)
{
        slave_t *slave;
        equalizer_t *eql;
        struct device *slave_dev;
        slave_config_t sc;
        int err;
 
        err = verify_area(VERIFY_READ, (void *)scp, sizeof (slave_config_t));
        if (err)
                return err;
 
        memcpy_fromfs (&sc, scp, sizeof (slave_config_t));
#ifdef EQL_DEBUG
        if (eql_debug >= 20)
                printk ("%s: get config for slave `%s'\n", dev->name, sc.slave_name);
#endif
        eql = (equalizer_t *) dev->priv;
        slave_dev = dev_get (sc.slave_name);
 
        if ( eql_is_slave (slave_dev) )
        {
                slave = eql_find_slave_dev (eql->queue,  slave_dev);
                if (slave != 0)
                {
                        sc.priority = slave->priority;
                        err = verify_area(VERIFY_WRITE, (void *)scp, sizeof (slave_config_t));
                        if (err)
                                return err;
                        memcpy_tofs (scp, &sc, sizeof (slave_config_t));
                        return 0;
                }
        }
        return -EINVAL;
}
 
 
static int eql_s_slave_cfg(struct device *dev, slave_config_t *scp)
{
        slave_t *slave;
        equalizer_t *eql;
        struct device *slave_dev;
        slave_config_t sc;
        int err;
 
        err = verify_area(VERIFY_READ, (void *)scp, sizeof (slave_config_t));
        if (err)
                return err;
 
#ifdef EQL_DEBUG
        if (eql_debug >= 20)
                printk ("%s: set config for slave `%s'\n", dev->name, sc.slave_name);
#endif
 
        memcpy_fromfs (&sc, scp, sizeof (slave_config_t));
 
        eql = (equalizer_t *) dev->priv;
        slave_dev = dev_get (sc.slave_name);
 
        if ( eql_is_slave (slave_dev) )
        {
                slave = eql_find_slave_dev (eql->queue, slave_dev);
                if (slave != 0)
                {
                        slave->priority = sc.priority;
                        slave->priority_bps = sc.priority;
                        slave->priority_Bps = sc.priority / 8;
                        return 0;
                }
        }
        return -EINVAL;
}
 
 
static int eql_g_master_cfg(struct device *dev, master_config_t *mcp)
{
        equalizer_t *eql;
        master_config_t mc;
 
#if EQL_DEBUG
        if (eql_debug >= 20)
                printk ("%s: get master config\n", dev->name);
#endif
 
        if ( eql_is_master (dev) )
        {
                int err;
                err = verify_area(VERIFY_WRITE, (void *)mcp, sizeof (master_config_t));
                if (err)
                        return err;
                eql = (equalizer_t *) dev->priv;
                mc.max_slaves = eql->max_slaves;
                mc.min_slaves = eql->min_slaves;
                memcpy_tofs (mcp, &mc, sizeof (master_config_t));
                return 0;
        }
        return -EINVAL;
}
 
 
static int eql_s_master_cfg(struct device *dev, master_config_t *mcp)
{
        equalizer_t *eql;
        master_config_t mc;
        int err;
 
        err = verify_area(VERIFY_READ, (void *)mcp, sizeof (master_config_t));
        if (err)
                return err;
#if EQL_DEBUG
        if (eql_debug >= 20)
                printk ("%s: set master config\n", dev->name);
#endif
        memcpy_fromfs (&mc, mcp, sizeof (master_config_t));
        if ( eql_is_master (dev) )
        {
                eql = (equalizer_t *) dev->priv;
                eql->max_slaves = mc.max_slaves;
                eql->min_slaves = mc.min_slaves;
                return 0;
        }
        return -EINVAL;
}
 
/*
 *      Private device support functions
 */
 
static inline int eql_is_slave(struct device *dev)
{
        if (dev)
        {
                if ((dev->flags & IFF_SLAVE) == IFF_SLAVE)
                        return 1;
        }
        return 0;
}
 
 
static inline int eql_is_master(struct device *dev)
{
        if (dev)
        {
                if ((dev->flags & IFF_MASTER) == IFF_MASTER)
                return 1;
        }
        return 0;
}
 
 
static slave_t *eql_new_slave(void)
{
        slave_t *slave;
 
        slave = (slave_t *) kmalloc (sizeof (slave_t), GFP_KERNEL);
        if (slave)
        {
                memset(slave, 0, sizeof (slave_t));
                return slave;
        }
        return 0;
}
 
 
static void eql_delete_slave(slave_t *slave)
{
        kfree (slave);
}
 
 
#if 0                           /* not currently used, will be used
                                   when we really use a priority queue */
static long slave_Bps(slave_t *slave)
{
        return (slave->priority_Bps);
}
 
static long slave_bps(slave_t *slave)
{
        return (slave->priority_bps);
}
 
#endif
 
static inline int eql_number_slaves(slave_queue_t *queue)
{
        return queue->num_slaves;
}
 
static inline int eql_is_empty(slave_queue_t *queue)
{
        if (eql_number_slaves (queue) == 0)
                return 1;
        return 0;
}
 
static inline int eql_is_full(slave_queue_t *queue)
{
        equalizer_t *eql = (equalizer_t *) queue->master_dev->priv;
 
        if (eql_number_slaves (queue) == eql->max_slaves)
                return 1;
        return 0;
}
 
static slave_queue_t *eql_new_slave_queue(struct device *dev)
{
        slave_queue_t *queue;
        slave_t *head_slave;
        slave_t *tail_slave;
 
        queue = (slave_queue_t *) kmalloc (sizeof (slave_queue_t), GFP_KERNEL);
        if (queue == NULL)
                return 0;
        memset (queue, 0, sizeof (slave_queue_t));
        head_slave = eql_new_slave ();
        tail_slave = eql_new_slave ();
 
        if ( head_slave != 0 &&
                tail_slave != 0 )
        {
                head_slave->next = tail_slave;
                tail_slave->next = 0;
                queue->head = head_slave;
                queue->num_slaves = 0;
                queue->master_dev = dev;
        }
        else
        {
                if (head_slave)
                        kfree(head_slave);
                if (tail_slave)
                        kfree(tail_slave);
                kfree (queue);
                return 0;
        }
        return queue;
}
 
 
static void eql_delete_slave_queue(slave_queue_t *queue)
{
        slave_t *zapped;
        /*
         *      This should only be called when there isn't a
         *      timer running that scans the data periodically..
         *      dev_close stops the timer...
         */
 
        while ( ! eql_is_empty (queue) )
        {
                zapped = eql_remove_slave (queue, queue->head->next);
                eql_delete_slave (zapped);
        }
        kfree (queue->head->next);
        kfree (queue->head);
        kfree (queue);
}
 
static int eql_insert_slave(slave_queue_t *queue, slave_t *slave)
{
        cli ();
 
        if ( ! eql_is_full (queue) )
        {
                slave_t *duplicate_slave = 0;
                duplicate_slave = eql_find_slave_dev (queue, slave->dev);
                if (duplicate_slave != 0)
                {
/*                        printk ("%s: found a duplicate, killing it and replacing\n",
                                  queue->master_dev->name); */
                        eql_delete_slave (eql_remove_slave (queue, duplicate_slave));
                }
                slave->next = queue->head->next;
                queue->head->next = slave;
                queue->num_slaves++;
                sti ();
                return 0;
        }
        sti ();
        return 1;
}
 
 
static slave_t *eql_remove_slave(slave_queue_t *queue, slave_t *slave)
{
        slave_t *prev;
        slave_t *curr;
 
        cli ();
 
        prev = queue->head;
        curr = queue->head->next;
        while (curr != slave &&
                curr->dev != 0 )
        {
/*              printk ("%s: remove_slave; searching...\n", queue->master_dev->name); */
                prev = curr;
                curr = curr->next;
        }
 
        if (curr == slave)
        {
                prev->next = curr->next;
                queue->num_slaves--;
                curr->dev->flags = curr->dev->flags & ~IFF_SLAVE;
                sti();
                return curr;
        }
        sti ();
        return 0;                        /* not found */
}
 
 
static int eql_remove_slave_dev(slave_queue_t *queue, struct device *dev)
{
        slave_t *prev;
        slave_t *curr;
        slave_t *target;
 
        target = eql_find_slave_dev (queue, dev);
 
        if (target != 0)
        {
                cli ();
                prev = queue->head;
                curr = prev->next;
                while (curr != target)
                {
                        prev = curr;
                        curr = curr->next;
                }
                prev->next = curr->next;
                queue->num_slaves--;
                sti ();
                eql_delete_slave (curr);
                return 0;
        }
        return 1;
}
 
 
static inline struct device *eql_best_slave_dev(slave_queue_t *queue)
{
        if (queue->best_slave != 0)
        {
                if (queue->best_slave->dev != 0)
                        return queue->best_slave->dev;
                else
                        return 0;
        }
        else
                return 0;
}
 
 
static inline slave_t *eql_best_slave(slave_queue_t *queue)
{
        return queue->best_slave;
}
 
static inline void eql_schedule_slaves(slave_queue_t *queue)
{
        struct device *master_dev = queue->master_dev;
        slave_t *best_slave = 0;
        slave_t *slave_corpse = 0;
 
#ifdef EQL_DEBUG
        if (eql_debug >= 100)
                printk ("%s: schedule %d slaves\n",
                        master_dev->name, eql_number_slaves (queue));
#endif
        if ( eql_is_empty (queue) )
        {
                /*
                 *      No slaves to play with
                 */
                eql_set_best_slave (queue, (slave_t *) 0);
                return;
        }
        else
        {
                /*
                 *      Make a pass to set the best slave
                 */
                unsigned long best_load = (unsigned long) ULONG_MAX;
                slave_t *slave = 0;
                int i;
 
                cli ();
                for (i = 1, slave = eql_first_slave (queue);
                        i <= eql_number_slaves (queue);
                        i++, slave = eql_next_slave (queue, slave))
                {
                        /*
                         *      Go through the slave list once, updating best_slave
                         *      whenever a new best_load is found, whenever a dead
                         *      slave is found, it is marked to be pulled out of the
                         *      queue
                         */
 
                        unsigned long slave_load;
                        unsigned long bytes_queued;
                        unsigned long priority_Bps;
 
                        if (slave != 0)
                        {
                                bytes_queued = slave->bytes_queued;
                                priority_Bps = slave->priority_Bps;
                                if ( slave->dev != 0)
                                {
                                        if ((slave->dev->flags & IFF_UP) == IFF_UP )
                                        {
                                                slave_load = (ULONG_MAX - (ULONG_MAX / 2)) -
                                                        (priority_Bps) + bytes_queued * 8;
 
                                                if (slave_load < best_load)
                                                {
                                                        best_load = slave_load;
                                                        best_slave = slave;
                                                }
                                        }
                                        else            /* we found a dead slave */
                                        {
                                                /*
                                                 *      We only bury one slave at a time, if more than
                                                 *      one slave dies, we will bury him on the next
                                                 *      reschedule. slaves don't die all at once that
                                                 *      much anyway
                                                 */
                                                slave_corpse = slave;
                                        }
                                }
                        }
                } /* for */
                sti ();
                eql_set_best_slave (queue, best_slave);
        } /* else */
        if (slave_corpse != 0)
        {
                printk ("eql: scheduler found dead slave, burying...\n");
                eql_delete_slave (eql_remove_slave (queue, slave_corpse));
        }
        return;
}
 
 
static slave_t * eql_find_slave_dev(slave_queue_t *queue, struct device *dev)
{
        slave_t *slave = 0;
        slave = eql_first_slave(queue);
 
        while (slave != 0 && slave->dev != dev && slave != 0)
        {
#if 0
                if (slave->dev != 0)
                        printk ("eql: find_slave_dev; looked at '%s'...\n", slave->dev->name);
                else
                        printk ("eql: find_slave_dev; looked at nothing...\n");
#endif
                slave = slave->next;
        }
        return slave;
}
 
 
static inline slave_t *eql_first_slave(slave_queue_t *queue)
{
        return queue->head->next;
}
 
 
static inline slave_t *eql_next_slave(slave_queue_t *queue, slave_t *slave)
{
        return slave->next;
}
 
static inline void eql_set_best_slave(slave_queue_t *queue, slave_t *slave)
{
        queue->best_slave = slave;
}
 
static void eql_timer(unsigned long param)
{
        equalizer_t *eql = (equalizer_t *) param;
        slave_t *slave;
        slave_t *slave_corpse = 0;
        int i;
 
        if ( ! eql_is_empty (eql->queue) )
        {
                cli ();
                for (i = 1, slave = eql_first_slave (eql->queue);
                        i <= eql_number_slaves (eql->queue);
                        i++, slave = eql_next_slave (eql->queue, slave))
                {
                        if (slave != 0)
                        {
                                if ((slave->dev->flags & IFF_UP) == IFF_UP )
                                {
                                        slave->bytes_queued -= slave->priority_Bps;
                                        if (slave->bytes_queued < 0)
                                                slave->bytes_queued = 0;
                                }
                                else
                                        slave_corpse = slave;
                        }
                }
                sti ();
                if (slave_corpse != 0)
                {
                        printk ("eql: timer found dead slave, burying...\n");
                        eql_delete_slave (eql_remove_slave (eql->queue, slave_corpse));
                }
        }
 
        if (eql->timer_on != 0)
        {
                eql->timer.expires = jiffies+EQL_DEFAULT_RESCHED_IVAL;
                add_timer (&eql->timer);
        }
}
 
#ifdef MODULE
static struct device dev_eql =
{
        "eql", 0, 0, 0, 0, 0, 0, 0, 0, 0, NULL, eql_init
};
 
int init_module(void)
{
        if (register_netdev(&dev_eql) != 0) {
                printk("eql: register_netdev() returned non-zero.\n");
                return -EIO;
        }
        return 0;
}
 
void cleanup_module(void)
{
        unregister_netdev(&dev_eql);
}
#endif /* MODULE */
 
/*
 * Local Variables:
 * compile-command: "gcc -D__KERNEL__ -I/usr/src/linux/net/inet -Wall -Wstrict-prototypes -O6 -m486 -c eql.c"
 * version-control: t
 * kept-new-versions: 20
 * End:
 */
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Line No.	Rev	Author	Line
1	1626	jcastillo	`/*`
2			`* Equalizer Load-balancer for serial network interfaces.`
3			`*`
4			`* (c) Copyright 1995 Simon "Guru Aleph-Null" Janes`
5			`* NCM: Network and Communications Management, Inc.`
6			`*`
7			`*`
8			`* This software may be used and distributed according to the terms`
9			`* of the GNU Public License, incorporated herein by reference.`
10			`*`
11			`* The author may be reached as simon@ncm.com, or C/O`
12			`* NCM`
13			`* Attn: Simon Janes`
14			`* 6803 Whittier Ave`
15			`* McLean VA 22101`
16			`* Phone: 1-703-847-0040 ext 103`
17			`*/`
18
19			`static const char *version =`
20			`"Equalizer1996: $Revision: 1.1 $ $Date: 2005-12-20 10:17:14 $ Simon Janes (simon@ncm.com)\n";`
21
22			`/*`
23			`* Sources:`
24			`* skeleton.c by Donald Becker.`
25			`* Inspirations:`
26			`* The Harried and Overworked Alan Cox`
27			`* Conspiracies:`
28			`* The Alan Cox and Mike McLagan plot to get someone else to do the code,`
29			`* which turned out to be me.`
30			`*/`
31
32			`/*`
33			`* $Log: not supported by cvs2svn $`
34			`* Revision 1.1.1.1 2001/09/10 07:44:23 simons`
35			`* Initial import`
36			`*`
37			`* Revision 1.1.1.1 2001/07/02 17:58:23 simons`
38			`* Initial revision`
39			`*`
40			`* Revision 1.9 1996/10/12 11:14:37 davem`