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