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0001 /*
0002  * Equalizer Load-balancer for serial network interfaces.
0003  *
0004  * (c) Copyright 1995 Simon "Guru Aleph-Null" Janes
0005  * NCM: Network and Communications Management, Inc.
0006  *
0007  * (c) Copyright 2002 David S. Miller (davem@redhat.com)
0008  *
0009  *  This software may be used and distributed according to the terms
0010  *  of the GNU General Public License, incorporated herein by reference.
0011  *
0012  * The author may be reached as simon@ncm.com, or C/O
0013  *    NCM
0014  *    Attn: Simon Janes
0015  *    6803 Whittier Ave
0016  *    McLean VA 22101
0017  *    Phone: 1-703-847-0040 ext 103
0018  */
0019 
0020 /*
0021  * Sources:
0022  *   skeleton.c by Donald Becker.
0023  * Inspirations:
0024  *   The Harried and Overworked Alan Cox
0025  * Conspiracies:
0026  *   The Alan Cox and Mike McLagan plot to get someone else to do the code,
0027  *   which turned out to be me.
0028  */
0029 
0030 /*
0031  * $Log: eql.c,v $
0032  * Revision 1.2  1996/04/11 17:51:52  guru
0033  * Added one-line eql_remove_slave patch.
0034  *
0035  * Revision 1.1  1996/04/11 17:44:17  guru
0036  * Initial revision
0037  *
0038  * Revision 3.13  1996/01/21  15:17:18  alan
0039  * tx_queue_len changes.
0040  * reformatted.
0041  *
0042  * Revision 3.12  1995/03/22  21:07:51  anarchy
0043  * Added capable() checks on configuration.
0044  * Moved header file.
0045  *
0046  * Revision 3.11  1995/01/19  23:14:31  guru
0047  *            slave_load = (ULONG_MAX - (ULONG_MAX / 2)) -
0048  *          (priority_Bps) + bytes_queued * 8;
0049  *
0050  * Revision 3.10  1995/01/19  23:07:53  guru
0051  * back to
0052  *            slave_load = (ULONG_MAX - (ULONG_MAX / 2)) -
0053  *          (priority_Bps) + bytes_queued;
0054  *
0055  * Revision 3.9  1995/01/19  22:38:20  guru
0056  *            slave_load = (ULONG_MAX - (ULONG_MAX / 2)) -
0057  *          (priority_Bps) + bytes_queued * 4;
0058  *
0059  * Revision 3.8  1995/01/19  22:30:55  guru
0060  *       slave_load = (ULONG_MAX - (ULONG_MAX / 2)) -
0061  *          (priority_Bps) + bytes_queued * 2;
0062  *
0063  * Revision 3.7  1995/01/19  21:52:35  guru
0064  * printk's trimmed out.
0065  *
0066  * Revision 3.6  1995/01/19  21:49:56  guru
0067  * This is working pretty well. I gained 1 K/s in speed.. now it's just
0068  * robustness and printk's to be diked out.
0069  *
0070  * Revision 3.5  1995/01/18  22:29:59  guru
0071  * still crashes the kernel when the lock_wait thing is woken up.
0072  *
0073  * Revision 3.4  1995/01/18  21:59:47  guru
0074  * Broken set-bit locking snapshot
0075  *
0076  * Revision 3.3  1995/01/17  22:09:18  guru
0077  * infinite sleep in a lock somewhere..
0078  *
0079  * Revision 3.2  1995/01/15  16:46:06  guru
0080  * Log trimmed of non-pertinent 1.x branch messages
0081  *
0082  * Revision 3.1  1995/01/15  14:41:45  guru
0083  * New Scheduler and timer stuff...
0084  *
0085  * Revision 1.15  1995/01/15  14:29:02  guru
0086  * Will make 1.14 (now 1.15) the 3.0 branch, and the 1.12 the 2.0 branch, the one
0087  * with the dumber scheduler
0088  *
0089  * Revision 1.14  1995/01/15  02:37:08  guru
0090  * shock.. the kept-new-versions could have zonked working
0091  * stuff.. shudder
0092  *
0093  * Revision 1.13  1995/01/15  02:36:31  guru
0094  * big changes
0095  *
0096  *  scheduler was torn out and replaced with something smarter
0097  *
0098  *  global names not prefixed with eql_ were renamed to protect
0099  *  against namespace collisions
0100  *
0101  *  a few more abstract interfaces were added to facilitate any
0102  *  potential change of datastructure.  the driver is still using
0103  *  a linked list of slaves.  going to a heap would be a bit of
0104  *  an overkill.
0105  *
0106  *  this compiles fine with no warnings.
0107  *
0108  *  the locking mechanism and timer stuff must be written however,
0109  *  this version will not work otherwise
0110  *
0111  * Sorry, I had to rewrite most of this for 2.5.x -DaveM
0112  */
0113 
0114 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
0115 
0116 #include <linux/compat.h>
0117 #include <linux/capability.h>
0118 #include <linux/module.h>
0119 #include <linux/kernel.h>
0120 #include <linux/init.h>
0121 #include <linux/slab.h>
0122 #include <linux/timer.h>
0123 #include <linux/netdevice.h>
0124 #include <net/net_namespace.h>
0125 
0126 #include <linux/if.h>
0127 #include <linux/if_arp.h>
0128 #include <linux/if_eql.h>
0129 #include <linux/pkt_sched.h>
0130 
0131 #include <linux/uaccess.h>
0132 
0133 static int eql_open(struct net_device *dev);
0134 static int eql_close(struct net_device *dev);
0135 static int eql_siocdevprivate(struct net_device *dev, struct ifreq *ifr,
0136                   void __user *data, int cmd);
0137 static netdev_tx_t eql_slave_xmit(struct sk_buff *skb, struct net_device *dev);
0138 
0139 #define eql_is_slave(dev)   ((dev->flags & IFF_SLAVE) == IFF_SLAVE)
0140 #define eql_is_master(dev)  ((dev->flags & IFF_MASTER) == IFF_MASTER)
0141 
0142 static void eql_kill_one_slave(slave_queue_t *queue, slave_t *slave);
0143 
0144 static void eql_timer(struct timer_list *t)
0145 {
0146     equalizer_t *eql = from_timer(eql, t, timer);
0147     struct list_head *this, *tmp, *head;
0148 
0149     spin_lock(&eql->queue.lock);
0150     head = &eql->queue.all_slaves;
0151     list_for_each_safe(this, tmp, head) {
0152         slave_t *slave = list_entry(this, slave_t, list);
0153 
0154         if ((slave->dev->flags & IFF_UP) == IFF_UP) {
0155             slave->bytes_queued -= slave->priority_Bps;
0156             if (slave->bytes_queued < 0)
0157                 slave->bytes_queued = 0;
0158         } else {
0159             eql_kill_one_slave(&eql->queue, slave);
0160         }
0161 
0162     }
0163     spin_unlock(&eql->queue.lock);
0164 
0165     eql->timer.expires = jiffies + EQL_DEFAULT_RESCHED_IVAL;
0166     add_timer(&eql->timer);
0167 }
0168 
0169 static const char version[] __initconst =
0170     "Equalizer2002: Simon Janes (simon@ncm.com) and David S. Miller (davem@redhat.com)";
0171 
0172 static const struct net_device_ops eql_netdev_ops = {
0173     .ndo_open   = eql_open,
0174     .ndo_stop   = eql_close,
0175     .ndo_siocdevprivate = eql_siocdevprivate,
0176     .ndo_start_xmit = eql_slave_xmit,
0177 };
0178 
0179 static void __init eql_setup(struct net_device *dev)
0180 {
0181     equalizer_t *eql = netdev_priv(dev);
0182 
0183     timer_setup(&eql->timer, eql_timer, 0);
0184     eql->timer.expires      = jiffies + EQL_DEFAULT_RESCHED_IVAL;
0185 
0186     spin_lock_init(&eql->queue.lock);
0187     INIT_LIST_HEAD(&eql->queue.all_slaves);
0188     eql->queue.master_dev   = dev;
0189 
0190     dev->netdev_ops     = &eql_netdev_ops;
0191 
0192     /*
0193      *  Now we undo some of the things that eth_setup does
0194      *  that we don't like
0195      */
0196 
0197     dev->mtu            = EQL_DEFAULT_MTU;  /* set to 576 in if_eql.h */
0198     dev->flags          = IFF_MASTER;
0199 
0200     dev->type           = ARPHRD_SLIP;
0201     dev->tx_queue_len   = 5;        /* Hands them off fast */
0202     netif_keep_dst(dev);
0203 }
0204 
0205 static int eql_open(struct net_device *dev)
0206 {
0207     equalizer_t *eql = netdev_priv(dev);
0208 
0209     /* XXX We should force this off automatically for the user. */
0210     netdev_info(dev,
0211             "remember to turn off Van-Jacobson compression on your slave devices\n");
0212 
0213     BUG_ON(!list_empty(&eql->queue.all_slaves));
0214 
0215     eql->min_slaves = 1;
0216     eql->max_slaves = EQL_DEFAULT_MAX_SLAVES; /* 4 usually... */
0217 
0218     add_timer(&eql->timer);
0219 
0220     return 0;
0221 }
0222 
0223 static void eql_kill_one_slave(slave_queue_t *queue, slave_t *slave)
0224 {
0225     list_del(&slave->list);
0226     queue->num_slaves--;
0227     slave->dev->flags &= ~IFF_SLAVE;
0228     netdev_put(slave->dev, &slave->dev_tracker);
0229     kfree(slave);
0230 }
0231 
0232 static void eql_kill_slave_queue(slave_queue_t *queue)
0233 {
0234     struct list_head *head, *tmp, *this;
0235 
0236     spin_lock_bh(&queue->lock);
0237 
0238     head = &queue->all_slaves;
0239     list_for_each_safe(this, tmp, head) {
0240         slave_t *s = list_entry(this, slave_t, list);
0241 
0242         eql_kill_one_slave(queue, s);
0243     }
0244 
0245     spin_unlock_bh(&queue->lock);
0246 }
0247 
0248 static int eql_close(struct net_device *dev)
0249 {
0250     equalizer_t *eql = netdev_priv(dev);
0251 
0252     /*
0253      *  The timer has to be stopped first before we start hacking away
0254      *  at the data structure it scans every so often...
0255      */
0256 
0257     del_timer_sync(&eql->timer);
0258 
0259     eql_kill_slave_queue(&eql->queue);
0260 
0261     return 0;
0262 }
0263 
0264 static int eql_enslave(struct net_device *dev,  slaving_request_t __user *srq);
0265 static int eql_emancipate(struct net_device *dev, slaving_request_t __user *srq);
0266 
0267 static int eql_g_slave_cfg(struct net_device *dev, slave_config_t __user *sc);
0268 static int eql_s_slave_cfg(struct net_device *dev, slave_config_t __user *sc);
0269 
0270 static int eql_g_master_cfg(struct net_device *dev, master_config_t __user *mc);
0271 static int eql_s_master_cfg(struct net_device *dev, master_config_t __user *mc);
0272 
0273 static int eql_siocdevprivate(struct net_device *dev, struct ifreq *ifr,
0274                   void __user *data, int cmd)
0275 {
0276     if (cmd != EQL_GETMASTRCFG && cmd != EQL_GETSLAVECFG &&
0277         !capable(CAP_NET_ADMIN))
0278         return -EPERM;
0279 
0280     if (in_compat_syscall()) /* to be implemented */
0281         return -EOPNOTSUPP;
0282 
0283     switch (cmd) {
0284         case EQL_ENSLAVE:
0285             return eql_enslave(dev, data);
0286         case EQL_EMANCIPATE:
0287             return eql_emancipate(dev, data);
0288         case EQL_GETSLAVECFG:
0289             return eql_g_slave_cfg(dev, data);
0290         case EQL_SETSLAVECFG:
0291             return eql_s_slave_cfg(dev, data);
0292         case EQL_GETMASTRCFG:
0293             return eql_g_master_cfg(dev, data);
0294         case EQL_SETMASTRCFG:
0295             return eql_s_master_cfg(dev, data);
0296         default:
0297             return -EOPNOTSUPP;
0298     }
0299 }
0300 
0301 /* queue->lock must be held */
0302 static slave_t *__eql_schedule_slaves(slave_queue_t *queue)
0303 {
0304     unsigned long best_load = ~0UL;
0305     struct list_head *this, *tmp, *head;
0306     slave_t *best_slave;
0307 
0308     best_slave = NULL;
0309 
0310     /* Make a pass to set the best slave. */
0311     head = &queue->all_slaves;
0312     list_for_each_safe(this, tmp, head) {
0313         slave_t *slave = list_entry(this, slave_t, list);
0314         unsigned long slave_load, bytes_queued, priority_Bps;
0315 
0316         /* Go through the slave list once, updating best_slave
0317          * whenever a new best_load is found.
0318          */
0319         bytes_queued = slave->bytes_queued;
0320         priority_Bps = slave->priority_Bps;
0321         if ((slave->dev->flags & IFF_UP) == IFF_UP) {
0322             slave_load = (~0UL - (~0UL / 2)) -
0323                 (priority_Bps) + bytes_queued * 8;
0324 
0325             if (slave_load < best_load) {
0326                 best_load = slave_load;
0327                 best_slave = slave;
0328             }
0329         } else {
0330             /* We found a dead slave, kill it. */
0331             eql_kill_one_slave(queue, slave);
0332         }
0333     }
0334     return best_slave;
0335 }
0336 
0337 static netdev_tx_t eql_slave_xmit(struct sk_buff *skb, struct net_device *dev)
0338 {
0339     equalizer_t *eql = netdev_priv(dev);
0340     slave_t *slave;
0341 
0342     spin_lock(&eql->queue.lock);
0343 
0344     slave = __eql_schedule_slaves(&eql->queue);
0345     if (slave) {
0346         struct net_device *slave_dev = slave->dev;
0347 
0348         skb->dev = slave_dev;
0349         skb->priority = TC_PRIO_FILLER;
0350         slave->bytes_queued += skb->len;
0351         dev_queue_xmit(skb);
0352         dev->stats.tx_packets++;
0353     } else {
0354         dev->stats.tx_dropped++;
0355         dev_kfree_skb(skb);
0356     }
0357 
0358     spin_unlock(&eql->queue.lock);
0359 
0360     return NETDEV_TX_OK;
0361 }
0362 
0363 /*
0364  *  Private ioctl functions
0365  */
0366 
0367 /* queue->lock must be held */
0368 static slave_t *__eql_find_slave_dev(slave_queue_t *queue, struct net_device *dev)
0369 {
0370     struct list_head *this, *head;
0371 
0372     head = &queue->all_slaves;
0373     list_for_each(this, head) {
0374         slave_t *slave = list_entry(this, slave_t, list);
0375 
0376         if (slave->dev == dev)
0377             return slave;
0378     }
0379 
0380     return NULL;
0381 }
0382 
0383 static inline int eql_is_full(slave_queue_t *queue)
0384 {
0385     equalizer_t *eql = netdev_priv(queue->master_dev);
0386 
0387     if (queue->num_slaves >= eql->max_slaves)
0388         return 1;
0389     return 0;
0390 }
0391 
0392 /* queue->lock must be held */
0393 static int __eql_insert_slave(slave_queue_t *queue, slave_t *slave)
0394 {
0395     if (!eql_is_full(queue)) {
0396         slave_t *duplicate_slave = NULL;
0397 
0398         duplicate_slave = __eql_find_slave_dev(queue, slave->dev);
0399         if (duplicate_slave)
0400             eql_kill_one_slave(queue, duplicate_slave);
0401 
0402         netdev_hold(slave->dev, &slave->dev_tracker, GFP_ATOMIC);
0403         list_add(&slave->list, &queue->all_slaves);
0404         queue->num_slaves++;
0405         slave->dev->flags |= IFF_SLAVE;
0406 
0407         return 0;
0408     }
0409 
0410     return -ENOSPC;
0411 }
0412 
0413 static int eql_enslave(struct net_device *master_dev, slaving_request_t __user *srqp)
0414 {
0415     struct net_device *slave_dev;
0416     slaving_request_t srq;
0417 
0418     if (copy_from_user(&srq, srqp, sizeof (slaving_request_t)))
0419         return -EFAULT;
0420 
0421     slave_dev = __dev_get_by_name(&init_net, srq.slave_name);
0422     if (!slave_dev)
0423         return -ENODEV;
0424 
0425     if ((master_dev->flags & IFF_UP) == IFF_UP) {
0426         /* slave is not a master & not already a slave: */
0427         if (!eql_is_master(slave_dev) && !eql_is_slave(slave_dev)) {
0428             slave_t *s = kzalloc(sizeof(*s), GFP_KERNEL);
0429             equalizer_t *eql = netdev_priv(master_dev);
0430             int ret;
0431 
0432             if (!s)
0433                 return -ENOMEM;
0434 
0435             s->dev = slave_dev;
0436             s->priority = srq.priority;
0437             s->priority_bps = srq.priority;
0438             s->priority_Bps = srq.priority / 8;
0439 
0440             spin_lock_bh(&eql->queue.lock);
0441             ret = __eql_insert_slave(&eql->queue, s);
0442             if (ret)
0443                 kfree(s);
0444 
0445             spin_unlock_bh(&eql->queue.lock);
0446 
0447             return ret;
0448         }
0449     }
0450 
0451     return -EINVAL;
0452 }
0453 
0454 static int eql_emancipate(struct net_device *master_dev, slaving_request_t __user *srqp)
0455 {
0456     equalizer_t *eql = netdev_priv(master_dev);
0457     struct net_device *slave_dev;
0458     slaving_request_t srq;
0459     int ret;
0460 
0461     if (copy_from_user(&srq, srqp, sizeof (slaving_request_t)))
0462         return -EFAULT;
0463 
0464     slave_dev = __dev_get_by_name(&init_net, srq.slave_name);
0465     if (!slave_dev)
0466         return -ENODEV;
0467 
0468     ret = -EINVAL;
0469     spin_lock_bh(&eql->queue.lock);
0470     if (eql_is_slave(slave_dev)) {
0471         slave_t *slave = __eql_find_slave_dev(&eql->queue, slave_dev);
0472         if (slave) {
0473             eql_kill_one_slave(&eql->queue, slave);
0474             ret = 0;
0475         }
0476     }
0477     spin_unlock_bh(&eql->queue.lock);
0478 
0479     return ret;
0480 }
0481 
0482 static int eql_g_slave_cfg(struct net_device *dev, slave_config_t __user *scp)
0483 {
0484     equalizer_t *eql = netdev_priv(dev);
0485     slave_t *slave;
0486     struct net_device *slave_dev;
0487     slave_config_t sc;
0488     int ret;
0489 
0490     if (copy_from_user(&sc, scp, sizeof (slave_config_t)))
0491         return -EFAULT;
0492 
0493     slave_dev = __dev_get_by_name(&init_net, sc.slave_name);
0494     if (!slave_dev)
0495         return -ENODEV;
0496 
0497     ret = -EINVAL;
0498 
0499     spin_lock_bh(&eql->queue.lock);
0500     if (eql_is_slave(slave_dev)) {
0501         slave = __eql_find_slave_dev(&eql->queue, slave_dev);
0502         if (slave) {
0503             sc.priority = slave->priority;
0504             ret = 0;
0505         }
0506     }
0507     spin_unlock_bh(&eql->queue.lock);
0508 
0509     if (!ret && copy_to_user(scp, &sc, sizeof (slave_config_t)))
0510         ret = -EFAULT;
0511 
0512     return ret;
0513 }
0514 
0515 static int eql_s_slave_cfg(struct net_device *dev, slave_config_t __user *scp)
0516 {
0517     slave_t *slave;
0518     equalizer_t *eql;
0519     struct net_device *slave_dev;
0520     slave_config_t sc;
0521     int ret;
0522 
0523     if (copy_from_user(&sc, scp, sizeof (slave_config_t)))
0524         return -EFAULT;
0525 
0526     slave_dev = __dev_get_by_name(&init_net, sc.slave_name);
0527     if (!slave_dev)
0528         return -ENODEV;
0529 
0530     ret = -EINVAL;
0531 
0532     eql = netdev_priv(dev);
0533     spin_lock_bh(&eql->queue.lock);
0534     if (eql_is_slave(slave_dev)) {
0535         slave = __eql_find_slave_dev(&eql->queue, slave_dev);
0536         if (slave) {
0537             slave->priority = sc.priority;
0538             slave->priority_bps = sc.priority;
0539             slave->priority_Bps = sc.priority / 8;
0540             ret = 0;
0541         }
0542     }
0543     spin_unlock_bh(&eql->queue.lock);
0544 
0545     return ret;
0546 }
0547 
0548 static int eql_g_master_cfg(struct net_device *dev, master_config_t __user *mcp)
0549 {
0550     equalizer_t *eql;
0551     master_config_t mc;
0552 
0553     memset(&mc, 0, sizeof(master_config_t));
0554 
0555     if (eql_is_master(dev)) {
0556         eql = netdev_priv(dev);
0557         mc.max_slaves = eql->max_slaves;
0558         mc.min_slaves = eql->min_slaves;
0559         if (copy_to_user(mcp, &mc, sizeof (master_config_t)))
0560             return -EFAULT;
0561         return 0;
0562     }
0563     return -EINVAL;
0564 }
0565 
0566 static int eql_s_master_cfg(struct net_device *dev, master_config_t __user *mcp)
0567 {
0568     equalizer_t *eql;
0569     master_config_t mc;
0570 
0571     if (copy_from_user(&mc, mcp, sizeof (master_config_t)))
0572         return -EFAULT;
0573 
0574     if (eql_is_master(dev)) {
0575         eql = netdev_priv(dev);
0576         eql->max_slaves = mc.max_slaves;
0577         eql->min_slaves = mc.min_slaves;
0578         return 0;
0579     }
0580     return -EINVAL;
0581 }
0582 
0583 static struct net_device *dev_eql;
0584 
0585 static int __init eql_init_module(void)
0586 {
0587     int err;
0588 
0589     pr_info("%s\n", version);
0590 
0591     dev_eql = alloc_netdev(sizeof(equalizer_t), "eql", NET_NAME_UNKNOWN,
0592                    eql_setup);
0593     if (!dev_eql)
0594         return -ENOMEM;
0595 
0596     err = register_netdev(dev_eql);
0597     if (err)
0598         free_netdev(dev_eql);
0599     return err;
0600 }
0601 
0602 static void __exit eql_cleanup_module(void)
0603 {
0604     unregister_netdev(dev_eql);
0605     free_netdev(dev_eql);
0606 }
0607 
0608 module_init(eql_init_module);
0609 module_exit(eql_cleanup_module);
0610 MODULE_LICENSE("GPL");
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