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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 static struct net_device_stats *eql_get_stats(struct net_device *dev);
 132
 133 #define eql_is_slave(dev)       ((dev->flags & IFF_SLAVE) == IFF_SLAVE)
 134 #define eql_is_master(dev)      ((dev->flags & IFF_MASTER) == IFF_MASTER)
 135
 136 static void eql_kill_one_slave(slave_queue_t *queue, slave_t *slave);
 137
 138 static void eql_timer(unsigned long param)
 139 {
 140         equalizer_t *eql = (equalizer_t *) param;
 141         struct list_head *this, *tmp, *head;
 142
 143         spin_lock_bh(&eql->queue.lock);
 144         head = &eql->queue.all_slaves;
 145         list_for_each_safe(this, tmp, head) {
 146                 slave_t *slave = list_entry(this, slave_t, list);
 147
 148                 if ((slave->dev->flags & IFF_UP) == IFF_UP) {
 149                         slave->bytes_queued -= slave->priority_Bps;
 150                         if (slave->bytes_queued < 0)
 151                                 slave->bytes_queued = 0;
 152                 } else {
 153                         eql_kill_one_slave(&eql->queue, slave);
 154                 }
 155
 156         }
 157         spin_unlock_bh(&eql->queue.lock);
 158
 159         eql->timer.expires = jiffies + EQL_DEFAULT_RESCHED_IVAL;
 160         add_timer(&eql->timer);
 161 }
 162
 163 static char version[] __initdata =
 164         "Equalizer2002: Simon Janes (simon@ncm.com) and David S. Miller (davem@redhat.com)\n";
 165
 166 static void __init eql_setup(struct net_device *dev)
 167 {
 168         equalizer_t *eql = netdev_priv(dev);
 169
 170         init_timer(&eql->timer);
 171         eql->timer.data         = (unsigned long) eql;
 172         eql->timer.expires      = jiffies + EQL_DEFAULT_RESCHED_IVAL;
 173         eql->timer.function     = eql_timer;
 174
 175         spin_lock_init(&eql->queue.lock);
 176         INIT_LIST_HEAD(&eql->queue.all_slaves);
 177         eql->queue.master_dev   = dev;
 178
 179         dev->open               = eql_open;
 180         dev->stop               = eql_close;
 181         dev->do_ioctl           = eql_ioctl;
 182         dev->hard_start_xmit    = eql_slave_xmit;
 183         dev->get_stats          = eql_get_stats;
 184
 185         /*
 186          *      Now we undo some of the things that eth_setup does
 187          *      that we don't like
 188          */
 189
 190         dev->mtu                = EQL_DEFAULT_MTU;      /* set to 576 in if_eql.h */
 191         dev->flags              = IFF_MASTER;
 192
 193         dev->type               = ARPHRD_SLIP;
 194         dev->tx_queue_len       = 5;            /* Hands them off fast */
 195 }
 196
 197 static int eql_open(struct net_device *dev)
 198 {
 199         equalizer_t *eql = netdev_priv(dev);
 200
 201         /* XXX We should force this off automatically for the user. */
 202         printk(KERN_INFO "%s: remember to turn off Van-Jacobson compression on "
 203                "your slave devices.\n", dev->name);
 204
 205         BUG_ON(!list_empty(&eql->queue.all_slaves));
 206
 207         eql->min_slaves = 1;
 208         eql->max_slaves = EQL_DEFAULT_MAX_SLAVES; /* 4 usually... */
 209
 210         add_timer(&eql->timer);
 211
 212         return 0;
 213 }
 214
 215 static void eql_kill_one_slave(slave_queue_t *queue, slave_t *slave)
 216 {
 217         list_del(&slave->list);
 218         queue->num_slaves--;
 219         slave->dev->flags &= ~IFF_SLAVE;
 220         dev_put(slave->dev);
 221         kfree(slave);
 222 }
 223
 224 static void eql_kill_slave_queue(slave_queue_t *queue)
 225 {
 226         struct list_head *head, *tmp, *this;
 227
 228         spin_lock_bh(&queue->lock);
 229
 230         head = &queue->all_slaves;
 231         list_for_each_safe(this, tmp, head) {
 232                 slave_t *s = list_entry(this, slave_t, list);
 233
 234                 eql_kill_one_slave(queue, s);
 235         }
 236
 237         spin_unlock_bh(&queue->lock);
 238 }
 239
 240 static int eql_close(struct net_device *dev)
 241 {
 242         equalizer_t *eql = netdev_priv(dev);
 243
 244         /*
 245          *      The timer has to be stopped first before we start hacking away
 246          *      at the data structure it scans every so often...
 247          */
 248
 249         del_timer_sync(&eql->timer);
 250
 251         eql_kill_slave_queue(&eql->queue);
 252
 253         return 0;
 254 }
 255
 256 static int eql_enslave(struct net_device *dev,  slaving_request_t __user *srq);
 257 static int eql_emancipate(struct net_device *dev, slaving_request_t __user *srq);
 258
 259 static int eql_g_slave_cfg(struct net_device *dev, slave_config_t __user *sc);
 260 static int eql_s_slave_cfg(struct net_device *dev, slave_config_t __user *sc);
 261
 262 static int eql_g_master_cfg(struct net_device *dev, master_config_t __user *mc);
 263 static int eql_s_master_cfg(struct net_device *dev, master_config_t __user *mc);
 264
 265 static int eql_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 266 {
 267         if (cmd != EQL_GETMASTRCFG && cmd != EQL_GETSLAVECFG &&
 268             !capable(CAP_NET_ADMIN))
 269                 return -EPERM;
 270
 271         switch (cmd) {
 272                 case EQL_ENSLAVE:
 273                         return eql_enslave(dev, ifr->ifr_data);
 274                 case EQL_EMANCIPATE:
 275                         return eql_emancipate(dev, ifr->ifr_data);
 276                 case EQL_GETSLAVECFG:
 277                         return eql_g_slave_cfg(dev, ifr->ifr_data);
 278                 case EQL_SETSLAVECFG:
 279                         return eql_s_slave_cfg(dev, ifr->ifr_data);
 280                 case EQL_GETMASTRCFG:
 281                         return eql_g_master_cfg(dev, ifr->ifr_data);
 282                 case EQL_SETMASTRCFG:
 283                         return eql_s_master_cfg(dev, ifr->ifr_data);
 284                 default:
 285                         return -EOPNOTSUPP;
 286         };
 287 }
 288
 289 /* queue->lock must be held */
 290 static slave_t *__eql_schedule_slaves(slave_queue_t *queue)
 291 {
 292         unsigned long best_load = ~0UL;
 293         struct list_head *this, *tmp, *head;
 294         slave_t *best_slave;
 295
 296         best_slave = NULL;
 297
 298         /* Make a pass to set the best slave. */
 299         head = &queue->all_slaves;
 300         list_for_each_safe(this, tmp, head) {
 301                 slave_t *slave = list_entry(this, slave_t, list);
 302                 unsigned long slave_load, bytes_queued, priority_Bps;
 303
 304                 /* Go through the slave list once, updating best_slave
 305                  * whenever a new best_load is found.
 306                  */
 307                 bytes_queued = slave->bytes_queued;
 308                 priority_Bps = slave->priority_Bps;
 309                 if ((slave->dev->flags & IFF_UP) == IFF_UP) {
 310                         slave_load = (~0UL - (~0UL / 2)) -
 311                                 (priority_Bps) + bytes_queued * 8;
 312
 313                         if (slave_load < best_load) {
 314                                 best_load = slave_load;
 315                                 best_slave = slave;
 316                         }
 317                 } else {
 318                         /* We found a dead slave, kill it. */
 319                         eql_kill_one_slave(queue, slave);
 320                 }
 321         }
 322         return best_slave;
 323 }
 324
 325 static int eql_slave_xmit(struct sk_buff *skb, struct net_device *dev)
 326 {
 327         equalizer_t *eql = netdev_priv(dev);
 328         slave_t *slave;
 329
 330         spin_lock(&eql->queue.lock);
 331
 332         slave = __eql_schedule_slaves(&eql->queue);
 333         if (slave) {
 334                 struct net_device *slave_dev = slave->dev;
 335
 336                 skb->dev = slave_dev;
 337                 skb->priority = 1;
 338                 slave->bytes_queued += skb->len;
 339                 dev_queue_xmit(skb);
 340                 eql->stats.tx_packets++;
 341         } else {
 342                 eql->stats.tx_dropped++;
 343                 dev_kfree_skb(skb);
 344         }
 345
 346         spin_unlock(&eql->queue.lock);
 347
 348         return 0;
 349 }
 350
 351 static struct net_device_stats * eql_get_stats(struct net_device *dev)
 352 {
 353         equalizer_t *eql = netdev_priv(dev);
 354         return &eql->stats;
 355 }
 356
 357 /*
 358  *      Private ioctl functions
 359  */
 360
 361 /* queue->lock must be held */
 362 static slave_t *__eql_find_slave_dev(slave_queue_t *queue, struct net_device *dev)
 363 {
 364         struct list_head *this, *head;
 365
 366         head = &queue->all_slaves;
 367         list_for_each(this, head) {
 368                 slave_t *slave = list_entry(this, slave_t, list);
 369
 370                 if (slave->dev == dev)
 371                         return slave;
 372         }
 373
 374         return NULL;
 375 }
 376
 377 static inline int eql_is_full(slave_queue_t *queue)
 378 {
 379         equalizer_t *eql = netdev_priv(queue->master_dev);
 380
 381         if (queue->num_slaves >= eql->max_slaves)
 382                 return 1;
 383         return 0;
 384 }
 385
 386 /* queue->lock must be held */
 387 static int __eql_insert_slave(slave_queue_t *queue, slave_t *slave)
 388 {
 389         if (!eql_is_full(queue)) {
 390                 slave_t *duplicate_slave = NULL;
 391
 392                 duplicate_slave = __eql_find_slave_dev(queue, slave->dev);
 393                 if (duplicate_slave)
 394                         eql_kill_one_slave(queue, duplicate_slave);
 395
 396                 list_add(&slave->list, &queue->all_slaves);
 397                 queue->num_slaves++;
 398                 slave->dev->flags |= IFF_SLAVE;
 399
 400                 return 0;
 401         }
 402
 403         return -ENOSPC;
 404 }
 405
 406 static int eql_enslave(struct net_device *master_dev, slaving_request_t __user *srqp)
 407 {
 408         struct net_device *slave_dev;
 409         slaving_request_t srq;
 410
 411         if (copy_from_user(&srq, srqp, sizeof (slaving_request_t)))
 412                 return -EFAULT;
 413
 414         slave_dev  = dev_get_by_name(&init_net, srq.slave_name);
 415         if (slave_dev) {
 416                 if ((master_dev->flags & IFF_UP) == IFF_UP) {
 417                         /* slave is not a master & not already a slave: */
 418                         if (!eql_is_master(slave_dev) &&
 419                             !eql_is_slave(slave_dev)) {
 420                                 slave_t *s = kmalloc(sizeof(*s), GFP_KERNEL);
 421                                 equalizer_t *eql = netdev_priv(master_dev);
 422                                 int ret;
 423
 424                                 if (!s) {
 425                                         dev_put(slave_dev);
 426                                         return -ENOMEM;
 427                                 }
 428
 429                                 memset(s, 0, sizeof(*s));
 430                                 s->dev = slave_dev;
 431                                 s->priority = srq.priority;
 432                                 s->priority_bps = srq.priority;
 433                                 s->priority_Bps = srq.priority / 8;
 434
 435                                 spin_lock_bh(&eql->queue.lock);
 436                                 ret = __eql_insert_slave(&eql->queue, s);
 437                                 if (ret) {
 438                                         dev_put(slave_dev);
 439                                         kfree(s);
 440                                 }
 441                                 spin_unlock_bh(&eql->queue.lock);
 442
 443                                 return ret;
 444                         }
 445                 }
 446                 dev_put(slave_dev);
 447         }
 448
 449         return -EINVAL;
 450 }
 451
 452 static int eql_emancipate(struct net_device *master_dev, slaving_request_t __user *srqp)
 453 {
 454         equalizer_t *eql = netdev_priv(master_dev);
 455         struct net_device *slave_dev;
 456         slaving_request_t srq;
 457         int ret;
 458
 459         if (copy_from_user(&srq, srqp, sizeof (slaving_request_t)))
 460                 return -EFAULT;
 461
 462         slave_dev = dev_get_by_name(&init_net, srq.slave_name);
 463         ret = -EINVAL;
 464         if (slave_dev) {
 465                 spin_lock_bh(&eql->queue.lock);
 466
 467                 if (eql_is_slave(slave_dev)) {
 468                         slave_t *slave = __eql_find_slave_dev(&eql->queue,
 469                                                               slave_dev);
 470
 471                         if (slave) {
 472                                 eql_kill_one_slave(&eql->queue, slave);
 473                                 ret = 0;
 474                         }
 475                 }
 476                 dev_put(slave_dev);
 477
 478                 spin_unlock_bh(&eql->queue.lock);
 479         }
 480
 481         return ret;
 482 }
 483
 484 static int eql_g_slave_cfg(struct net_device *dev, slave_config_t __user *scp)
 485 {
 486         equalizer_t *eql = netdev_priv(dev);
 487         slave_t *slave;
 488         struct net_device *slave_dev;
 489         slave_config_t sc;
 490         int ret;
 491
 492         if (copy_from_user(&sc, scp, sizeof (slave_config_t)))
 493                 return -EFAULT;
 494
 495         slave_dev = dev_get_by_name(&init_net, sc.slave_name);
 496         if (!slave_dev)
 497                 return -ENODEV;
 498
 499         ret = -EINVAL;
 500
 501         spin_lock_bh(&eql->queue.lock);
 502         if (eql_is_slave(slave_dev)) {
 503                 slave = __eql_find_slave_dev(&eql->queue, slave_dev);
 504                 if (slave) {
 505                         sc.priority = slave->priority;
 506                         ret = 0;
 507                 }
 508         }
 509         spin_unlock_bh(&eql->queue.lock);
 510
 511         dev_put(slave_dev);
 512
 513         if (!ret && copy_to_user(scp, &sc, sizeof (slave_config_t)))
 514                 ret = -EFAULT;
 515
 516         return ret;
 517 }
 518
 519 static int eql_s_slave_cfg(struct net_device *dev, slave_config_t __user *scp)
 520 {
 521         slave_t *slave;
 522         equalizer_t *eql;
 523         struct net_device *slave_dev;
 524         slave_config_t sc;
 525         int ret;
 526
 527         if (copy_from_user(&sc, scp, sizeof (slave_config_t)))
 528                 return -EFAULT;
 529
 530         slave_dev = dev_get_by_name(&init_net, sc.slave_name);
 531         if (!slave_dev)
 532                 return -ENODEV;
 533
 534         ret = -EINVAL;
 535
 536         eql = netdev_priv(dev);
 537         spin_lock_bh(&eql->queue.lock);
 538         if (eql_is_slave(slave_dev)) {
 539                 slave = __eql_find_slave_dev(&eql->queue, slave_dev);
 540                 if (slave) {
 541                         slave->priority = sc.priority;
 542                         slave->priority_bps = sc.priority;
 543                         slave->priority_Bps = sc.priority / 8;
 544                         ret = 0;
 545                 }
 546         }
 547         spin_unlock_bh(&eql->queue.lock);
 548
 549         return ret;
 550 }
 551
 552 static int eql_g_master_cfg(struct net_device *dev, master_config_t __user *mcp)
 553 {
 554         equalizer_t *eql;
 555         master_config_t mc;
 556
 557         if (eql_is_master(dev)) {
 558                 eql = netdev_priv(dev);
 559                 mc.max_slaves = eql->max_slaves;
 560                 mc.min_slaves = eql->min_slaves;
 561                 if (copy_to_user(mcp, &mc, sizeof (master_config_t)))
 562                         return -EFAULT;
 563                 return 0;
 564         }
 565         return -EINVAL;
 566 }
 567
 568 static int eql_s_master_cfg(struct net_device *dev, master_config_t __user *mcp)
 569 {
 570         equalizer_t *eql;
 571         master_config_t mc;
 572
 573         if (copy_from_user(&mc, mcp, sizeof (master_config_t)))
 574                 return -EFAULT;
 575
 576         if (eql_is_master(dev)) {
 577                 eql = netdev_priv(dev);
 578                 eql->max_slaves = mc.max_slaves;
 579                 eql->min_slaves = mc.min_slaves;
 580                 return 0;
 581         }
 582         return -EINVAL;
 583 }
 584
 585 static struct net_device *dev_eql;
 586
 587 static int __init eql_init_module(void)
 588 {
 589         int err;
 590
 591         printk(version);
 592
 593         dev_eql = alloc_netdev(sizeof(equalizer_t), "eql", eql_setup);
 594         if (!dev_eql)
 595                 return -ENOMEM;
 596
 597         err = register_netdev(dev_eql);
 598         if (err)
 599                 free_netdev(dev_eql);
 600         return err;
 601 }
 602
 603 static void __exit eql_cleanup_module(void)
 604 {
 605         unregister_netdev(dev_eql);
 606         free_netdev(dev_eql);
 607 }
 608
 609 module_init(eql_init_module);
 610 module_exit(eql_cleanup_module);
 611 MODULE_LICENSE("GPL");