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   1 /*
   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  * (c) Copyright 2002 David S. Miller (davem@redhat.com)
   8  *
   9  *      This software may be used and distributed according to the terms
  10  *      of the GNU General Public License, incorporated herein by reference.
  11  *
  12  * The author may be reached as simon@ncm.com, or C/O
  13  *    NCM
  14  *    Attn: Simon Janes
  15  *    6803 Whittier Ave
  16  *    McLean VA 22101
  17  *    Phone: 1-703-847-0040 ext 103
  18  */
  19
  20 /*
  21  * Sources:
  22  *   skeleton.c by Donald Becker.
  23  * Inspirations:
  24  *   The Harried and Overworked Alan Cox
  25  * Conspiracies:
  26  *   The Alan Cox and Mike McLagan plot to get someone else to do the code,
  27  *   which turned out to be me.
  28  */
  29
  30 /*
  31  * $Log: eql.c,v $
  32  * Revision 1.2  1996/04/11 17:51:52  guru
  33  * Added one-line eql_remove_slave patch.
  34  *
  35  * Revision 1.1  1996/04/11 17:44:17  guru
  36  * Initial revision
  37  *
  38  * Revision 3.13  1996/01/21  15:17:18  alan
  39  * tx_queue_len changes.
  40  * reformatted.
  41  *
  42  * Revision 3.12  1995/03/22  21:07:51  anarchy
  43  * Added capable() checks on configuration.
  44  * Moved header file.
  45  *
  46  * Revision 3.11  1995/01/19  23:14:31  guru
  47  *                    slave_load = (ULONG_MAX - (ULONG_MAX / 2)) -
  48  *                      (priority_Bps) + bytes_queued * 8;
  49  *
  50  * Revision 3.10  1995/01/19  23:07:53  guru
  51  * back to
  52  *                    slave_load = (ULONG_MAX - (ULONG_MAX / 2)) -
  53  *                      (priority_Bps) + bytes_queued;
  54  *
  55  * Revision 3.9  1995/01/19  22:38:20  guru
  56  *                    slave_load = (ULONG_MAX - (ULONG_MAX / 2)) -
  57  *                      (priority_Bps) + bytes_queued * 4;
  58  *
  59  * Revision 3.8  1995/01/19  22:30:55  guru
  60  *       slave_load = (ULONG_MAX - (ULONG_MAX / 2)) -
  61  *                      (priority_Bps) + bytes_queued * 2;
  62  *
  63  * Revision 3.7  1995/01/19  21:52:35  guru
  64  * printk's trimmed out.
  65  *
  66  * Revision 3.6  1995/01/19  21:49:56  guru
  67  * This is working pretty well. I gained 1 K/s in speed.. now it's just
  68  * robustness and printk's to be diked out.
  69  *
  70  * Revision 3.5  1995/01/18  22:29:59  guru
  71  * still crashes the kernel when the lock_wait thing is woken up.
  72  *
  73  * Revision 3.4  1995/01/18  21:59:47  guru
  74  * Broken set-bit locking snapshot
  75  *
  76  * Revision 3.3  1995/01/17  22:09:18  guru
  77  * infinite sleep in a lock somewhere..
  78  *
  79  * Revision 3.2  1995/01/15  16:46:06  guru
  80  * Log trimmed of non-pertinent 1.x branch messages
  81  *
  82  * Revision 3.1  1995/01/15  14:41:45  guru
  83  * New Scheduler and timer stuff...
  84  *
  85  * Revision 1.15  1995/01/15  14:29:02  guru
  86  * Will make 1.14 (now 1.15) the 3.0 branch, and the 1.12 the 2.0 branch, the one
  87  * with the dumber scheduler
  88  *
  89  * Revision 1.14  1995/01/15  02:37:08  guru
  90  * shock.. the kept-new-versions could have zonked working
  91  * stuff.. shudder
  92  *
  93  * Revision 1.13  1995/01/15  02:36:31  guru
  94  * big changes
  95  *
  96  *      scheduler was torn out and replaced with something smarter
  97  *
  98  *      global names not prefixed with eql_ were renamed to protect
  99  *      against namespace collisions
 100  *
 101  *      a few more abstract interfaces were added to facilitate any
 102  *      potential change of datastructure.  the driver is still using
 103  *      a linked list of slaves.  going to a heap would be a bit of
 104  *      an overkill.
 105  *
 106  *      this compiles fine with no warnings.
 107  *
 108  *      the locking mechanism and timer stuff must be written however,
 109  *      this version will not work otherwise
 110  *
 111  * Sorry, I had to rewrite most of this for 2.5.x -DaveM
 112  */
 113
 114 #include <linux/module.h>
 115 #include <linux/kernel.h>
 116 #include <linux/init.h>
 117 #include <linux/timer.h>
 118 #include <linux/netdevice.h>
 119 #include <net/net_namespace.h>
 120
 121 #include <linux/if.h>
 122 #include <linux/if_arp.h>
 123 #include <linux/if_eql.h>
 124
 125 #include <asm/uaccess.h>
 126
 127 static int eql_open(struct net_device *dev);
 128 static int eql_close(struct net_device *dev);
 129 static int eql_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd);
 130 static int eql_slave_xmit(struct sk_buff *skb, struct net_device *dev);
 131
 132 #define eql_is_slave(dev)       ((dev->flags & IFF_SLAVE) == IFF_SLAVE)
 133 #define eql_is_master(dev)      ((dev->flags & IFF_MASTER) == IFF_MASTER)
 134
 135 static void eql_kill_one_slave(slave_queue_t *queue, slave_t *slave);
 136
 137 static void eql_timer(unsigned long param)
 138 {
 139         equalizer_t *eql = (equalizer_t *) param;
 140         struct list_head *this, *tmp, *head;
 141
 142         spin_lock_bh(&eql->queue.lock);
 143         head = &eql->queue.all_slaves;
 144         list_for_each_safe(this, tmp, head) {
 145                 slave_t *slave = list_entry(this, slave_t, list);
 146
 147                 if ((slave->dev->flags & IFF_UP) == IFF_UP) {
 148                         slave->bytes_queued -= slave->priority_Bps;
 149                         if (slave->bytes_queued < 0)
 150                                 slave->bytes_queued = 0;
 151                 } else {
 152                         eql_kill_one_slave(&eql->queue, slave);
 153                 }
 154
 155         }
 156         spin_unlock_bh(&eql->queue.lock);
 157
 158         eql->timer.expires = jiffies + EQL_DEFAULT_RESCHED_IVAL;
 159         add_timer(&eql->timer);
 160 }
 161
 162 static const char version[] __initconst =
 163         "Equalizer2002: Simon Janes (simon@ncm.com) and David S. Miller (davem@redhat.com)\n";
 164
 165 static const struct net_device_ops eql_netdev_ops = {
 166         .ndo_open       = eql_open,
 167         .ndo_stop       = eql_close,
 168         .ndo_do_ioctl   = eql_ioctl,
 169         .ndo_start_xmit = eql_slave_xmit,
 170 };
 171
 172 static void __init eql_setup(struct net_device *dev)
 173 {
 174         equalizer_t *eql = netdev_priv(dev);
 175
 176         init_timer(&eql->timer);
 177         eql->timer.data         = (unsigned long) eql;
 178         eql->timer.expires      = jiffies + EQL_DEFAULT_RESCHED_IVAL;
 179         eql->timer.function     = eql_timer;
 180
 181         spin_lock_init(&eql->queue.lock);
 182         INIT_LIST_HEAD(&eql->queue.all_slaves);
 183         eql->queue.master_dev   = dev;
 184
 185         dev->netdev_ops         = &eql_netdev_ops;
 186
 187         /*
 188          *      Now we undo some of the things that eth_setup does
 189          *      that we don't like
 190          */
 191
 192         dev->mtu                = EQL_DEFAULT_MTU;      /* set to 576 in if_eql.h */
 193         dev->flags              = IFF_MASTER;
 194
 195         dev->type               = ARPHRD_SLIP;
 196         dev->tx_queue_len       = 5;            /* Hands them off fast */
 197         dev->priv_flags        &= ~IFF_XMIT_DST_RELEASE;
 198 }
 199
 200 static int eql_open(struct net_device *dev)
 201 {
 202         equalizer_t *eql = netdev_priv(dev);
 203
 204         /* XXX We should force this off automatically for the user. */
 205         printk(KERN_INFO "%s: remember to turn off Van-Jacobson compression on "
 206                "your slave devices.\n", dev->name);
 207
 208         BUG_ON(!list_empty(&eql->queue.all_slaves));
 209
 210         eql->min_slaves = 1;
 211         eql->max_slaves = EQL_DEFAULT_MAX_SLAVES; /* 4 usually... */
 212
 213         add_timer(&eql->timer);
 214
 215         return 0;
 216 }
 217
 218 static void eql_kill_one_slave(slave_queue_t *queue, slave_t *slave)
 219 {
 220         list_del(&slave->list);
 221         queue->num_slaves--;
 222         slave->dev->flags &= ~IFF_SLAVE;
 223         dev_put(slave->dev);
 224         kfree(slave);
 225 }
 226
 227 static void eql_kill_slave_queue(slave_queue_t *queue)
 228 {
 229         struct list_head *head, *tmp, *this;
 230
 231         spin_lock_bh(&queue->lock);
 232
 233         head = &queue->all_slaves;
 234         list_for_each_safe(this, tmp, head) {
 235                 slave_t *s = list_entry(this, slave_t, list);
 236
 237                 eql_kill_one_slave(queue, s);
 238         }
 239
 240         spin_unlock_bh(&queue->lock);
 241 }
 242
 243 static int eql_close(struct net_device *dev)
 244 {
 245         equalizer_t *eql = netdev_priv(dev);
 246
 247         /*
 248          *      The timer has to be stopped first before we start hacking away
 249          *      at the data structure it scans every so often...
 250          */
 251
 252         del_timer_sync(&eql->timer);
 253
 254         eql_kill_slave_queue(&eql->queue);
 255
 256         return 0;
 257 }
 258
 259 static int eql_enslave(struct net_device *dev,  slaving_request_t __user *srq);
 260 static int eql_emancipate(struct net_device *dev, slaving_request_t __user *srq);
 261
 262 static int eql_g_slave_cfg(struct net_device *dev, slave_config_t __user *sc);
 263 static int eql_s_slave_cfg(struct net_device *dev, slave_config_t __user *sc);
 264
 265 static int eql_g_master_cfg(struct net_device *dev, master_config_t __user *mc);
 266 static int eql_s_master_cfg(struct net_device *dev, master_config_t __user *mc);
 267
 268 static int eql_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 269 {
 270         if (cmd != EQL_GETMASTRCFG && cmd != EQL_GETSLAVECFG &&
 271             !capable(CAP_NET_ADMIN))
 272                 return -EPERM;
 273
 274         switch (cmd) {
 275                 case EQL_ENSLAVE:
 276                         return eql_enslave(dev, ifr->ifr_data);
 277                 case EQL_EMANCIPATE:
 278                         return eql_emancipate(dev, ifr->ifr_data);
 279                 case EQL_GETSLAVECFG:
 280                         return eql_g_slave_cfg(dev, ifr->ifr_data);
 281                 case EQL_SETSLAVECFG:
 282                         return eql_s_slave_cfg(dev, ifr->ifr_data);
 283                 case EQL_GETMASTRCFG:
 284                         return eql_g_master_cfg(dev, ifr->ifr_data);
 285                 case EQL_SETMASTRCFG:
 286                         return eql_s_master_cfg(dev, ifr->ifr_data);
 287                 default:
 288                         return -EOPNOTSUPP;
 289         };
 290 }
 291
 292 /* queue->lock must be held */
 293 static slave_t *__eql_schedule_slaves(slave_queue_t *queue)
 294 {
 295         unsigned long best_load = ~0UL;
 296         struct list_head *this, *tmp, *head;
 297         slave_t *best_slave;
 298
 299         best_slave = NULL;
 300
 301         /* Make a pass to set the best slave. */
 302         head = &queue->all_slaves;
 303         list_for_each_safe(this, tmp, head) {
 304                 slave_t *slave = list_entry(this, slave_t, list);
 305                 unsigned long slave_load, bytes_queued, priority_Bps;
 306
 307                 /* Go through the slave list once, updating best_slave
 308                  * whenever a new best_load is found.
 309                  */
 310                 bytes_queued = slave->bytes_queued;
 311                 priority_Bps = slave->priority_Bps;
 312                 if ((slave->dev->flags & IFF_UP) == IFF_UP) {
 313                         slave_load = (~0UL - (~0UL / 2)) -
 314                                 (priority_Bps) + bytes_queued * 8;
 315
 316                         if (slave_load < best_load) {
 317                                 best_load = slave_load;
 318                                 best_slave = slave;
 319                         }
 320                 } else {
 321                         /* We found a dead slave, kill it. */
 322                         eql_kill_one_slave(queue, slave);
 323                 }
 324         }
 325         return best_slave;
 326 }
 327
 328 static int eql_slave_xmit(struct sk_buff *skb, struct net_device *dev)
 329 {
 330         equalizer_t *eql = netdev_priv(dev);
 331         slave_t *slave;
 332
 333         spin_lock(&eql->queue.lock);
 334
 335         slave = __eql_schedule_slaves(&eql->queue);
 336         if (slave) {
 337                 struct net_device *slave_dev = slave->dev;
 338
 339                 skb->dev = slave_dev;
 340                 skb->priority = 1;
 341                 slave->bytes_queued += skb->len;
 342                 dev_queue_xmit(skb);
 343                 dev->stats.tx_packets++;
 344         } else {
 345                 dev->stats.tx_dropped++;
 346                 dev_kfree_skb(skb);
 347         }
 348
 349         spin_unlock(&eql->queue.lock);
 350
 351         return 0;
 352 }
 353
 354 /*
 355  *      Private ioctl functions
 356  */
 357
 358 /* queue->lock must be held */
 359 static slave_t *__eql_find_slave_dev(slave_queue_t *queue, struct net_device *dev)
 360 {
 361         struct list_head *this, *head;
 362
 363         head = &queue->all_slaves;
 364         list_for_each(this, head) {
 365                 slave_t *slave = list_entry(this, slave_t, list);
 366
 367                 if (slave->dev == dev)
 368                         return slave;
 369         }
 370
 371         return NULL;
 372 }
 373
 374 static inline int eql_is_full(slave_queue_t *queue)
 375 {
 376         equalizer_t *eql = netdev_priv(queue->master_dev);
 377
 378         if (queue->num_slaves >= eql->max_slaves)
 379                 return 1;
 380         return 0;
 381 }
 382
 383 /* queue->lock must be held */
 384 static int __eql_insert_slave(slave_queue_t *queue, slave_t *slave)
 385 {
 386         if (!eql_is_full(queue)) {
 387                 slave_t *duplicate_slave = NULL;
 388
 389                 duplicate_slave = __eql_find_slave_dev(queue, slave->dev);
 390                 if (duplicate_slave)
 391                         eql_kill_one_slave(queue, duplicate_slave);
 392
 393                 list_add(&slave->list, &queue->all_slaves);
 394                 queue->num_slaves++;
 395                 slave->dev->flags |= IFF_SLAVE;
 396
 397                 return 0;
 398         }
 399
 400         return -ENOSPC;
 401 }
 402
 403 static int eql_enslave(struct net_device *master_dev, slaving_request_t __user *srqp)
 404 {
 405         struct net_device *slave_dev;
 406         slaving_request_t srq;
 407
 408         if (copy_from_user(&srq, srqp, sizeof (slaving_request_t)))
 409                 return -EFAULT;
 410
 411         slave_dev  = dev_get_by_name(&init_net, srq.slave_name);
 412         if (slave_dev) {
 413                 if ((master_dev->flags & IFF_UP) == IFF_UP) {
 414                         /* slave is not a master & not already a slave: */
 415                         if (!eql_is_master(slave_dev) &&
 416                             !eql_is_slave(slave_dev)) {
 417                                 slave_t *s = kmalloc(sizeof(*s), GFP_KERNEL);
 418                                 equalizer_t *eql = netdev_priv(master_dev);
 419                                 int ret;
 420
 421                                 if (!s) {
 422                                         dev_put(slave_dev);
 423                                         return -ENOMEM;
 424                                 }
 425
 426                                 memset(s, 0, sizeof(*s));
 427                                 s->dev = slave_dev;
 428                                 s->priority = srq.priority;
 429                                 s->priority_bps = srq.priority;
 430                                 s->priority_Bps = srq.priority / 8;
 431
 432                                 spin_lock_bh(&eql->queue.lock);
 433                                 ret = __eql_insert_slave(&eql->queue, s);
 434                                 if (ret) {
 435                                         dev_put(slave_dev);
 436                                         kfree(s);
 437                                 }
 438                                 spin_unlock_bh(&eql->queue.lock);
 439
 440                                 return ret;
 441                         }
 442                 }
 443                 dev_put(slave_dev);
 444         }
 445
 446         return -EINVAL;
 447 }
 448
 449 static int eql_emancipate(struct net_device *master_dev, slaving_request_t __user *srqp)
 450 {
 451         equalizer_t *eql = netdev_priv(master_dev);
 452         struct net_device *slave_dev;
 453         slaving_request_t srq;
 454         int ret;
 455
 456         if (copy_from_user(&srq, srqp, sizeof (slaving_request_t)))
 457                 return -EFAULT;
 458
 459         slave_dev = dev_get_by_name(&init_net, srq.slave_name);
 460         ret = -EINVAL;
 461         if (slave_dev) {
 462                 spin_lock_bh(&eql->queue.lock);
 463
 464                 if (eql_is_slave(slave_dev)) {
 465                         slave_t *slave = __eql_find_slave_dev(&eql->queue,
 466                                                               slave_dev);
 467
 468                         if (slave) {
 469                                 eql_kill_one_slave(&eql->queue, slave);
 470                                 ret = 0;
 471                         }
 472                 }
 473                 dev_put(slave_dev);
 474
 475                 spin_unlock_bh(&eql->queue.lock);
 476         }
 477
 478         return ret;
 479 }
 480
 481 static int eql_g_slave_cfg(struct net_device *dev, slave_config_t __user *scp)
 482 {
 483         equalizer_t *eql = netdev_priv(dev);
 484         slave_t *slave;
 485         struct net_device *slave_dev;
 486         slave_config_t sc;
 487         int ret;
 488
 489         if (copy_from_user(&sc, scp, sizeof (slave_config_t)))
 490                 return -EFAULT;
 491
 492         slave_dev = dev_get_by_name(&init_net, sc.slave_name);
 493         if (!slave_dev)
 494                 return -ENODEV;
 495
 496         ret = -EINVAL;
 497
 498         spin_lock_bh(&eql->queue.lock);
 499         if (eql_is_slave(slave_dev)) {
 500                 slave = __eql_find_slave_dev(&eql->queue, slave_dev);
 501                 if (slave) {
 502                         sc.priority = slave->priority;
 503                         ret = 0;
 504                 }
 505         }
 506         spin_unlock_bh(&eql->queue.lock);
 507
 508         dev_put(slave_dev);
 509
 510         if (!ret && copy_to_user(scp, &sc, sizeof (slave_config_t)))
 511                 ret = -EFAULT;
 512
 513         return ret;
 514 }
 515
 516 static int eql_s_slave_cfg(struct net_device *dev, slave_config_t __user *scp)
 517 {
 518         slave_t *slave;
 519         equalizer_t *eql;
 520         struct net_device *slave_dev;
 521         slave_config_t sc;
 522         int ret;
 523
 524         if (copy_from_user(&sc, scp, sizeof (slave_config_t)))
 525                 return -EFAULT;
 526
 527         slave_dev = dev_get_by_name(&init_net, sc.slave_name);
 528         if (!slave_dev)
 529                 return -ENODEV;
 530
 531         ret = -EINVAL;
 532
 533         eql = netdev_priv(dev);
 534         spin_lock_bh(&eql->queue.lock);
 535         if (eql_is_slave(slave_dev)) {
 536                 slave = __eql_find_slave_dev(&eql->queue, slave_dev);
 537                 if (slave) {
 538                         slave->priority = sc.priority;
 539                         slave->priority_bps = sc.priority;
 540                         slave->priority_Bps = sc.priority / 8;
 541                         ret = 0;
 542                 }
 543         }
 544         spin_unlock_bh(&eql->queue.lock);
 545
 546         dev_put(slave_dev);
 547
 548         return ret;
 549 }
 550
 551 static int eql_g_master_cfg(struct net_device *dev, master_config_t __user *mcp)
 552 {
 553         equalizer_t *eql;
 554         master_config_t mc;
 555
 556         if (eql_is_master(dev)) {
 557                 eql = netdev_priv(dev);
 558                 mc.max_slaves = eql->max_slaves;
 559                 mc.min_slaves = eql->min_slaves;
 560                 if (copy_to_user(mcp, &mc, sizeof (master_config_t)))
 561                         return -EFAULT;
 562                 return 0;
 563         }
 564         return -EINVAL;
 565 }
 566
 567 static int eql_s_master_cfg(struct net_device *dev, master_config_t __user *mcp)
 568 {
 569         equalizer_t *eql;
 570         master_config_t mc;
 571
 572         if (copy_from_user(&mc, mcp, sizeof (master_config_t)))
 573                 return -EFAULT;
 574
 575         if (eql_is_master(dev)) {
 576                 eql = netdev_priv(dev);
 577                 eql->max_slaves = mc.max_slaves;
 578                 eql->min_slaves = mc.min_slaves;
 579                 return 0;
 580         }
 581         return -EINVAL;
 582 }
 583
 584 static struct net_device *dev_eql;
 585
 586 static int __init eql_init_module(void)
 587 {
 588         int err;
 589
 590         printk(version);
 591
 592         dev_eql = alloc_netdev(sizeof(equalizer_t), "eql", eql_setup);
 593         if (!dev_eql)
 594                 return -ENOMEM;
 595
 596         err = register_netdev(dev_eql);
 597         if (err)
 598                 free_netdev(dev_eql);
 599         return err;
 600 }
 601
 602 static void __exit eql_cleanup_module(void)
 603 {
 604         unregister_netdev(dev_eql);
 605         free_netdev(dev_eql);
 606 }
 607
 608 module_init(eql_init_module);
 609 module_exit(eql_cleanup_module);
 610 MODULE_LICENSE("GPL");