drivers/net/eql.c

   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
 120 #include <linux/if.h>
 121 #include <linux/if_arp.h>
 122 #include <linux/if_eql.h>
 123
 124 #include <asm/uaccess.h>
 125
 126 static int eql_open(struct net_device *dev);
 127 static int eql_close(struct net_device *dev);
 128 static int eql_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd);
 129 static int eql_slave_xmit(struct sk_buff *skb, struct net_device *dev);
 130 static struct net_device_stats *eql_get_stats(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_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(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 char version[] __initdata =
 163         "Equalizer2002: Simon Janes (simon@ncm.com) and David S. Miller (davem@redhat.com)\n";
 164
 165 static void __init eql_setup(struct net_device *dev)
 166 {
 167         equalizer_t *eql = dev->priv;
 168
 169         SET_MODULE_OWNER(dev);
 170
 171         init_timer(&eql->timer);
 172         eql->timer.data         = (unsigned long) dev->priv;
 173         eql->timer.expires      = jiffies + EQL_DEFAULT_RESCHED_IVAL;
 174         eql->timer.function     = eql_timer;
 175
 176         spin_lock_init(&eql->queue.lock);
 177         INIT_LIST_HEAD(&eql->queue.all_slaves);
 178         eql->queue.master_dev   = dev;
 179
 180         dev->open               = eql_open;
 181         dev->stop               = eql_close;
 182         dev->do_ioctl           = eql_ioctl;
 183         dev->hard_start_xmit    = eql_slave_xmit;
 184         dev->get_stats          = eql_get_stats;
 185
 186         /*
 187          *      Now we undo some of the things that eth_setup does
 188          *      that we don't like
 189          */
 190
 191         dev->mtu                = EQL_DEFAULT_MTU;      /* set to 576 in if_eql.h */
 192         dev->flags              = IFF_MASTER;
 193
 194         dev->type               = ARPHRD_SLIP;
 195         dev->tx_queue_len       = 5;            /* Hands them off fast */
 196 }
 197
 198 static int eql_open(struct net_device *dev)
 199 {
 200         equalizer_t *eql = dev->priv;
 201
 202         /* XXX We should force this off automatically for the user. */
 203         printk(KERN_INFO "%s: remember to turn off Van-Jacobson compression on "
 204                "your slave devices.\n", dev->name);
 205
 206         if (!list_empty(&eql->queue.all_slaves))
 207                 BUG();
 208
 209         eql->min_slaves = 1;
 210         eql->max_slaves = EQL_DEFAULT_MAX_SLAVES; /* 4 usually... */
 211
 212         add_timer(&eql->timer);
 213
 214         return 0;
 215 }
 216
 217 static void eql_kill_one_slave(slave_t *slave)
 218 {
 219         list_del(&slave->list);
 220         slave->dev->flags &= ~IFF_SLAVE;
 221         dev_put(slave->dev);
 222         kfree(slave);
 223 }
 224
 225 static void eql_kill_slave_queue(slave_queue_t *queue)
 226 {
 227         struct list_head *head, *tmp, *this;
 228
 229         spin_lock_bh(&queue->lock);
 230
 231         head = &queue->all_slaves;
 232         list_for_each_safe(this, tmp, head) {
 233                 slave_t *s = list_entry(this, slave_t, list);
 234
 235                 eql_kill_one_slave(s);
 236                 queue->num_slaves--;
 237         }
 238
 239         spin_unlock_bh(&queue->lock);
 240 }
 241
 242 static int eql_close(struct net_device *dev)
 243 {
 244         equalizer_t *eql = dev->priv;
 245
 246         /*
 247          *      The timer has to be stopped first before we start hacking away
 248          *      at the data structure it scans every so often...
 249          */
 250
 251         del_timer_sync(&eql->timer);
 252
 253         eql_kill_slave_queue(&eql->queue);
 254
 255         return 0;
 256 }
 257
 258 static int eql_enslave(struct net_device *dev,  slaving_request_t *srq);
 259 static int eql_emancipate(struct net_device *dev, slaving_request_t *srq);
 260
 261 static int eql_g_slave_cfg(struct net_device *dev, slave_config_t *sc);
 262 static int eql_s_slave_cfg(struct net_device *dev, slave_config_t *sc);
 263
 264 static int eql_g_master_cfg(struct net_device *dev, master_config_t *mc);
 265 static int eql_s_master_cfg(struct net_device *dev, master_config_t *mc);
 266
 267 static int eql_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 268 {
 269         if (cmd != EQL_GETMASTRCFG && cmd != EQL_GETSLAVECFG &&
 270             !capable(CAP_NET_ADMIN))
 271                 return -EPERM;
 272
 273         switch (cmd) {
 274                 case EQL_ENSLAVE:
 275                         return eql_enslave(dev,
 276                                            (slaving_request_t *) ifr->ifr_data);
 277                 case EQL_EMANCIPATE:
 278                         return eql_emancipate(dev,
 279                                               (slaving_request_t *) ifr->ifr_data);
 280                 case EQL_GETSLAVECFG:
 281                         return eql_g_slave_cfg(dev,
 282                                                (slave_config_t *) ifr->ifr_data);
 283                 case EQL_SETSLAVECFG:
 284                         return eql_s_slave_cfg(dev,
 285                                                (slave_config_t *) ifr->ifr_data);
 286                 case EQL_GETMASTRCFG:
 287                         return eql_g_master_cfg(dev,
 288                                                 (master_config_t *) ifr->ifr_data);
 289                 case EQL_SETMASTRCFG:
 290                         return eql_s_master_cfg(dev,
 291                                                 (master_config_t *) ifr->ifr_data);
 292                 default:
 293                         return -EOPNOTSUPP;
 294         };
 295 }
 296
 297 /* queue->lock must be held */
 298 static slave_t *__eql_schedule_slaves(slave_queue_t *queue)
 299 {
 300         unsigned long best_load = ~0UL;
 301         struct list_head *this, *tmp, *head;
 302         slave_t *best_slave;
 303
 304         best_slave = NULL;
 305
 306         /* Make a pass to set the best slave. */
 307         head = &queue->all_slaves;
 308         list_for_each_safe(this, tmp, head) {
 309                 slave_t *slave = list_entry(this, slave_t, list);
 310                 unsigned long slave_load, bytes_queued, priority_Bps;
 311
 312                 /* Go through the slave list once, updating best_slave
 313                  * whenever a new best_load is found.
 314                  */
 315                 bytes_queued = slave->bytes_queued;
 316                 priority_Bps = slave->priority_Bps;
 317                 if ((slave->dev->flags & IFF_UP) == IFF_UP) {
 318                         slave_load = (~0UL - (~0UL / 2)) -
 319                                 (priority_Bps) + bytes_queued * 8;
 320
 321                         if (slave_load < best_load) {
 322                                 best_load = slave_load;
 323                                 best_slave = slave;
 324                         }
 325                 } else {
 326                         /* We found a dead slave, kill it. */
 327                         eql_kill_one_slave(slave);
 328                 }
 329         }
 330         return best_slave;
 331 }
 332
 333 static int eql_slave_xmit(struct sk_buff *skb, struct net_device *dev)
 334 {
 335         equalizer_t *eql = dev->priv;
 336         slave_t *slave;
 337
 338         spin_lock(&eql->queue.lock);
 339
 340         slave = __eql_schedule_slaves(&eql->queue);
 341         if (slave) {
 342                 struct net_device *slave_dev = slave->dev;
 343
 344                 skb->dev = slave_dev;
 345                 skb->priority = 1;
 346                 slave->bytes_queued += skb->len;
 347                 dev_queue_xmit(skb);
 348                 eql->stats.tx_packets++;
 349         } else {
 350                 eql->stats.tx_dropped++;
 351                 dev_kfree_skb(skb);
 352         }
 353
 354         spin_unlock(&eql->queue.lock);
 355
 356         return 0;
 357 }
 358
 359 static struct net_device_stats * eql_get_stats(struct net_device *dev)
 360 {
 361         equalizer_t *eql = dev->priv;
 362         return &eql->stats;
 363 }
 364
 365 /*
 366  *      Private ioctl functions
 367  */
 368
 369 /* queue->lock must be held */
 370 static slave_t *__eql_find_slave_dev(slave_queue_t *queue, struct net_device *dev)
 371 {
 372         struct list_head *this, *head;
 373
 374         head = &queue->all_slaves;
 375         list_for_each(this, head) {
 376                 slave_t *slave = list_entry(this, slave_t, list);
 377
 378                 if (slave->dev == dev)
 379                         return slave;
 380         }
 381
 382         return NULL;
 383 }
 384
 385 static inline int eql_is_full(slave_queue_t *queue)
 386 {
 387         equalizer_t *eql = queue->master_dev->priv;
 388
 389         if (queue->num_slaves >= eql->max_slaves)
 390                 return 1;
 391         return 0;
 392 }
 393
 394 /* queue->lock must be held */
 395 static int __eql_insert_slave(slave_queue_t *queue, slave_t *slave)
 396 {
 397         if (!eql_is_full(queue)) {
 398                 slave_t *duplicate_slave = 0;
 399
 400                 duplicate_slave = __eql_find_slave_dev(queue, slave->dev);
 401                 if (duplicate_slave != 0)
 402                         eql_kill_one_slave(duplicate_slave);
 403
 404                 list_add(&slave->list, &queue->all_slaves);
 405                 queue->num_slaves++;
 406                 slave->dev->flags |= IFF_SLAVE;
 407
 408                 return 0;
 409         }
 410
 411         return -ENOSPC;
 412 }
 413
 414 static int eql_enslave(struct net_device *master_dev, slaving_request_t *srqp)
 415 {
 416         struct net_device *slave_dev;
 417         slaving_request_t srq;
 418
 419         if (copy_from_user(&srq, srqp, sizeof (slaving_request_t)))
 420                 return -EFAULT;
 421
 422         slave_dev  = dev_get_by_name(srq.slave_name);
 423         if (slave_dev) {
 424                 if ((master_dev->flags & IFF_UP) == IFF_UP) {
 425                         /* slave is not a master & not already a slave: */
 426                         if (!eql_is_master(slave_dev) &&
 427                             !eql_is_slave(slave_dev)) {
 428                                 slave_t *s = kmalloc(sizeof(*s), GFP_KERNEL);
 429                                 equalizer_t *eql = master_dev->priv;
 430                                 int ret;
 431
 432                                 if (!s) {
 433                                         dev_put(slave_dev);
 434                                         return -ENOMEM;
 435                                 }
 436
 437                                 memset(s, 0, sizeof(*s));
 438                                 s->dev = slave_dev;
 439                                 s->priority = srq.priority;
 440                                 s->priority_bps = srq.priority;
 441                                 s->priority_Bps = srq.priority / 8;
 442
 443                                 spin_lock_bh(&eql->queue.lock);
 444                                 ret = __eql_insert_slave(&eql->queue, s);
 445                                 if (ret) {
 446                                         dev_put(slave_dev);
 447                                         kfree(s);
 448                                 }
 449                                 spin_unlock_bh(&eql->queue.lock);
 450
 451                                 return ret;
 452                         }
 453                 }
 454                 dev_put(slave_dev);
 455         }
 456
 457         return -EINVAL;
 458 }
 459
 460 static int eql_emancipate(struct net_device *master_dev, slaving_request_t *srqp)
 461 {
 462         equalizer_t *eql = master_dev->priv;
 463         struct net_device *slave_dev;
 464         slaving_request_t srq;
 465         int ret;
 466
 467         if (copy_from_user(&srq, srqp, sizeof (slaving_request_t)))
 468                 return -EFAULT;
 469
 470         slave_dev = dev_get_by_name(srq.slave_name);
 471         ret = -EINVAL;
 472         if (slave_dev) {
 473                 spin_lock_bh(&eql->queue.lock);
 474
 475                 if (eql_is_slave(slave_dev)) {
 476                         slave_t *slave = __eql_find_slave_dev(&eql->queue,
 477                                                               slave_dev);
 478
 479                         if (slave) {
 480                                 eql_kill_one_slave(slave);
 481                                 ret = 0;
 482                         }
 483                 }
 484                 dev_put(slave_dev);
 485
 486                 spin_unlock_bh(&eql->queue.lock);
 487         }
 488
 489         return ret;
 490 }
 491
 492 static int eql_g_slave_cfg(struct net_device *dev, slave_config_t *scp)
 493 {
 494         equalizer_t *eql = dev->priv;
 495         slave_t *slave;
 496         struct net_device *slave_dev;
 497         slave_config_t sc;
 498         int ret;
 499
 500         if (copy_from_user(&sc, scp, sizeof (slave_config_t)))
 501                 return -EFAULT;
 502
 503         slave_dev = dev_get_by_name(sc.slave_name);
 504
 505         ret = -EINVAL;
 506
 507         spin_lock_bh(&eql->queue.lock);
 508         if (eql_is_slave(slave_dev)) {
 509                 slave = __eql_find_slave_dev(&eql->queue, slave_dev);
 510                 if (slave) {
 511                         sc.priority = slave->priority;
 512                         ret = 0;
 513                 }
 514         }
 515         spin_unlock_bh(&eql->queue.lock);
 516
 517         dev_put(slave_dev);
 518
 519         if (!ret && copy_to_user(scp, &sc, sizeof (slave_config_t)))
 520                 ret = -EFAULT;
 521
 522         return ret;
 523 }
 524
 525 static int eql_s_slave_cfg(struct net_device *dev, slave_config_t *scp)
 526 {
 527         slave_t *slave;
 528         equalizer_t *eql;
 529         struct net_device *slave_dev;
 530         slave_config_t sc;
 531         int ret;
 532
 533         if (copy_from_user(&sc, scp, sizeof (slave_config_t)))
 534                 return -EFAULT;
 535
 536         eql = dev->priv;
 537         slave_dev = dev_get_by_name(sc.slave_name);
 538
 539         ret = -EINVAL;
 540
 541         spin_lock_bh(&eql->queue.lock);
 542         if (eql_is_slave(slave_dev)) {
 543                 slave = __eql_find_slave_dev(&eql->queue, slave_dev);
 544                 if (slave) {
 545                         slave->priority = sc.priority;
 546                         slave->priority_bps = sc.priority;
 547                         slave->priority_Bps = sc.priority / 8;
 548                         ret = 0;
 549                 }
 550         }
 551         spin_unlock_bh(&eql->queue.lock);
 552
 553         return ret;
 554 }
 555
 556 static int eql_g_master_cfg(struct net_device *dev, master_config_t *mcp)
 557 {
 558         equalizer_t *eql;
 559         master_config_t mc;
 560
 561         if (eql_is_master(dev)) {
 562                 eql = dev->priv;
 563                 mc.max_slaves = eql->max_slaves;
 564                 mc.min_slaves = eql->min_slaves;
 565                 if (copy_to_user(mcp, &mc, sizeof (master_config_t)))
 566                         return -EFAULT;
 567                 return 0;
 568         }
 569         return -EINVAL;
 570 }
 571
 572 static int eql_s_master_cfg(struct net_device *dev, master_config_t *mcp)
 573 {
 574         equalizer_t *eql;
 575         master_config_t mc;
 576
 577         if (copy_from_user(&mc, mcp, sizeof (master_config_t)))
 578                 return -EFAULT;
 579
 580         if (eql_is_master(dev)) {
 581                 eql = dev->priv;
 582                 eql->max_slaves = mc.max_slaves;
 583                 eql->min_slaves = mc.min_slaves;
 584                 return 0;
 585         }
 586         return -EINVAL;
 587 }
 588
 589 static struct net_device *dev_eql;
 590
 591 static int __init eql_init_module(void)
 592 {
 593         int err;
 594
 595         printk(version);
 596
 597         dev_eql = alloc_netdev(sizeof(equalizer_t), "eql", eql_setup);
 598         if (!dev_eql)
 599                 return -ENOMEM;
 600
 601         err = register_netdev(dev_eql);
 602         if (err)
 603                 free_netdev(dev_eql);
 604         return err;
 605 }
 606
 607 static void __exit eql_cleanup_module(void)
 608 {
 609         unregister_netdev(dev_eql);
 610         free_netdev(dev_eql);
 611 }
 612
 613 module_init(eql_init_module);
 614 module_exit(eql_cleanup_module);
 615 MODULE_LICENSE("GPL");