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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 115
 116 #include <linux/capability.h>
 117 #include <linux/module.h>
 118 #include <linux/kernel.h>
 119 #include <linux/init.h>
 120 #include <linux/slab.h>
 121 #include <linux/timer.h>
 122 #include <linux/netdevice.h>
 123 #include <net/net_namespace.h>
 124
 125 #include <linux/if.h>
 126 #include <linux/if_arp.h>
 127 #include <linux/if_eql.h>
 128
 129 #include <asm/uaccess.h>
 130
 131 static int eql_open(struct net_device *dev);
 132 static int eql_close(struct net_device *dev);
 133 static int eql_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd);
 134 static netdev_tx_t eql_slave_xmit(struct sk_buff *skb, struct net_device *dev);
 135
 136 #define eql_is_slave(dev)       ((dev->flags & IFF_SLAVE) == IFF_SLAVE)
 137 #define eql_is_master(dev)      ((dev->flags & IFF_MASTER) == IFF_MASTER)
 138
 139 static void eql_kill_one_slave(slave_queue_t *queue, slave_t *slave);
 140
 141 static void eql_timer(unsigned long param)
 142 {
 143         equalizer_t *eql = (equalizer_t *) param;
 144         struct list_head *this, *tmp, *head;
 145
 146         spin_lock_bh(&eql->queue.lock);
 147         head = &eql->queue.all_slaves;
 148         list_for_each_safe(this, tmp, head) {
 149                 slave_t *slave = list_entry(this, slave_t, list);
 150
 151                 if ((slave->dev->flags & IFF_UP) == IFF_UP) {
 152                         slave->bytes_queued -= slave->priority_Bps;
 153                         if (slave->bytes_queued < 0)
 154                                 slave->bytes_queued = 0;
 155                 } else {
 156                         eql_kill_one_slave(&eql->queue, slave);
 157                 }
 158
 159         }
 160         spin_unlock_bh(&eql->queue.lock);
 161
 162         eql->timer.expires = jiffies + EQL_DEFAULT_RESCHED_IVAL;
 163         add_timer(&eql->timer);
 164 }
 165
 166 static const char version[] __initconst =
 167         "Equalizer2002: Simon Janes (simon@ncm.com) and David S. Miller (davem@redhat.com)";
 168
 169 static const struct net_device_ops eql_netdev_ops = {
 170         .ndo_open       = eql_open,
 171         .ndo_stop       = eql_close,
 172         .ndo_do_ioctl   = eql_ioctl,
 173         .ndo_start_xmit = eql_slave_xmit,
 174 };
 175
 176 static void __init eql_setup(struct net_device *dev)
 177 {
 178         equalizer_t *eql = netdev_priv(dev);
 179
 180         init_timer(&eql->timer);
 181         eql->timer.data         = (unsigned long) eql;
 182         eql->timer.expires      = jiffies + EQL_DEFAULT_RESCHED_IVAL;
 183         eql->timer.function     = eql_timer;
 184
 185         spin_lock_init(&eql->queue.lock);
 186         INIT_LIST_HEAD(&eql->queue.all_slaves);
 187         eql->queue.master_dev   = dev;
 188
 189         dev->netdev_ops         = &eql_netdev_ops;
 190
 191         /*
 192          *      Now we undo some of the things that eth_setup does
 193          *      that we don't like
 194          */
 195
 196         dev->mtu                = EQL_DEFAULT_MTU;      /* set to 576 in if_eql.h */
 197         dev->flags              = IFF_MASTER;
 198
 199         dev->type               = ARPHRD_SLIP;
 200         dev->tx_queue_len       = 5;            /* Hands them off fast */
 201         dev->priv_flags        &= ~IFF_XMIT_DST_RELEASE;
 202 }
 203
 204 static int eql_open(struct net_device *dev)
 205 {
 206         equalizer_t *eql = netdev_priv(dev);
 207
 208         /* XXX We should force this off automatically for the user. */
 209         netdev_info(dev,
 210                     "remember to turn off Van-Jacobson compression on your slave devices\n");
 211
 212         BUG_ON(!list_empty(&eql->queue.all_slaves));
 213
 214         eql->min_slaves = 1;
 215         eql->max_slaves = EQL_DEFAULT_MAX_SLAVES; /* 4 usually... */
 216
 217         add_timer(&eql->timer);
 218
 219         return 0;
 220 }
 221
 222 static void eql_kill_one_slave(slave_queue_t *queue, slave_t *slave)
 223 {
 224         list_del(&slave->list);
 225         queue->num_slaves--;
 226         slave->dev->flags &= ~IFF_SLAVE;
 227         dev_put(slave->dev);
 228         kfree(slave);
 229 }
 230
 231 static void eql_kill_slave_queue(slave_queue_t *queue)
 232 {
 233         struct list_head *head, *tmp, *this;
 234
 235         spin_lock_bh(&queue->lock);
 236
 237         head = &queue->all_slaves;
 238         list_for_each_safe(this, tmp, head) {
 239                 slave_t *s = list_entry(this, slave_t, list);
 240
 241                 eql_kill_one_slave(queue, s);
 242         }
 243
 244         spin_unlock_bh(&queue->lock);
 245 }
 246
 247 static int eql_close(struct net_device *dev)
 248 {
 249         equalizer_t *eql = netdev_priv(dev);
 250
 251         /*
 252          *      The timer has to be stopped first before we start hacking away
 253          *      at the data structure it scans every so often...
 254          */
 255
 256         del_timer_sync(&eql->timer);
 257
 258         eql_kill_slave_queue(&eql->queue);
 259
 260         return 0;
 261 }
 262
 263 static int eql_enslave(struct net_device *dev,  slaving_request_t __user *srq);
 264 static int eql_emancipate(struct net_device *dev, slaving_request_t __user *srq);
 265
 266 static int eql_g_slave_cfg(struct net_device *dev, slave_config_t __user *sc);
 267 static int eql_s_slave_cfg(struct net_device *dev, slave_config_t __user *sc);
 268
 269 static int eql_g_master_cfg(struct net_device *dev, master_config_t __user *mc);
 270 static int eql_s_master_cfg(struct net_device *dev, master_config_t __user *mc);
 271
 272 static int eql_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 273 {
 274         if (cmd != EQL_GETMASTRCFG && cmd != EQL_GETSLAVECFG &&
 275             !capable(CAP_NET_ADMIN))
 276                 return -EPERM;
 277
 278         switch (cmd) {
 279                 case EQL_ENSLAVE:
 280                         return eql_enslave(dev, ifr->ifr_data);
 281                 case EQL_EMANCIPATE:
 282                         return eql_emancipate(dev, ifr->ifr_data);
 283                 case EQL_GETSLAVECFG:
 284                         return eql_g_slave_cfg(dev, ifr->ifr_data);
 285                 case EQL_SETSLAVECFG:
 286                         return eql_s_slave_cfg(dev, ifr->ifr_data);
 287                 case EQL_GETMASTRCFG:
 288                         return eql_g_master_cfg(dev, ifr->ifr_data);
 289                 case EQL_SETMASTRCFG:
 290                         return eql_s_master_cfg(dev, ifr->ifr_data);
 291                 default:
 292                         return -EOPNOTSUPP;
 293         }
 294 }
 295
 296 /* queue->lock must be held */
 297 static slave_t *__eql_schedule_slaves(slave_queue_t *queue)
 298 {
 299         unsigned long best_load = ~0UL;
 300         struct list_head *this, *tmp, *head;
 301         slave_t *best_slave;
 302
 303         best_slave = NULL;
 304
 305         /* Make a pass to set the best slave. */
 306         head = &queue->all_slaves;
 307         list_for_each_safe(this, tmp, head) {
 308                 slave_t *slave = list_entry(this, slave_t, list);
 309                 unsigned long slave_load, bytes_queued, priority_Bps;
 310
 311                 /* Go through the slave list once, updating best_slave
 312                  * whenever a new best_load is found.
 313                  */
 314                 bytes_queued = slave->bytes_queued;
 315                 priority_Bps = slave->priority_Bps;
 316                 if ((slave->dev->flags & IFF_UP) == IFF_UP) {
 317                         slave_load = (~0UL - (~0UL / 2)) -
 318                                 (priority_Bps) + bytes_queued * 8;
 319
 320                         if (slave_load < best_load) {
 321                                 best_load = slave_load;
 322                                 best_slave = slave;
 323                         }
 324                 } else {
 325                         /* We found a dead slave, kill it. */
 326                         eql_kill_one_slave(queue, slave);
 327                 }
 328         }
 329         return best_slave;
 330 }
 331
 332 static netdev_tx_t eql_slave_xmit(struct sk_buff *skb, struct net_device *dev)
 333 {
 334         equalizer_t *eql = netdev_priv(dev);
 335         slave_t *slave;
 336
 337         spin_lock(&eql->queue.lock);
 338
 339         slave = __eql_schedule_slaves(&eql->queue);
 340         if (slave) {
 341                 struct net_device *slave_dev = slave->dev;
 342
 343                 skb->dev = slave_dev;
 344                 skb->priority = 1;
 345                 slave->bytes_queued += skb->len;
 346                 dev_queue_xmit(skb);
 347                 dev->stats.tx_packets++;
 348         } else {
 349                 dev->stats.tx_dropped++;
 350                 dev_kfree_skb(skb);
 351         }
 352
 353         spin_unlock(&eql->queue.lock);
 354
 355         return NETDEV_TX_OK;
 356 }
 357
 358 /*
 359  *      Private ioctl functions
 360  */
 361
 362 /* queue->lock must be held */
 363 static slave_t *__eql_find_slave_dev(slave_queue_t *queue, struct net_device *dev)
 364 {
 365         struct list_head *this, *head;
 366
 367         head = &queue->all_slaves;
 368         list_for_each(this, head) {
 369                 slave_t *slave = list_entry(this, slave_t, list);
 370
 371                 if (slave->dev == dev)
 372                         return slave;
 373         }
 374
 375         return NULL;
 376 }
 377
 378 static inline int eql_is_full(slave_queue_t *queue)
 379 {
 380         equalizer_t *eql = netdev_priv(queue->master_dev);
 381
 382         if (queue->num_slaves >= eql->max_slaves)
 383                 return 1;
 384         return 0;
 385 }
 386
 387 /* queue->lock must be held */
 388 static int __eql_insert_slave(slave_queue_t *queue, slave_t *slave)
 389 {
 390         if (!eql_is_full(queue)) {
 391                 slave_t *duplicate_slave = NULL;
 392
 393                 duplicate_slave = __eql_find_slave_dev(queue, slave->dev);
 394                 if (duplicate_slave)
 395                         eql_kill_one_slave(queue, duplicate_slave);
 396
 397                 list_add(&slave->list, &queue->all_slaves);
 398                 queue->num_slaves++;
 399                 slave->dev->flags |= IFF_SLAVE;
 400
 401                 return 0;
 402         }
 403
 404         return -ENOSPC;
 405 }
 406
 407 static int eql_enslave(struct net_device *master_dev, slaving_request_t __user *srqp)
 408 {
 409         struct net_device *slave_dev;
 410         slaving_request_t srq;
 411
 412         if (copy_from_user(&srq, srqp, sizeof (slaving_request_t)))
 413                 return -EFAULT;
 414
 415         slave_dev  = dev_get_by_name(&init_net, srq.slave_name);
 416         if (slave_dev) {
 417                 if ((master_dev->flags & IFF_UP) == IFF_UP) {
 418                         /* slave is not a master & not already a slave: */
 419                         if (!eql_is_master(slave_dev) &&
 420                             !eql_is_slave(slave_dev)) {
 421                                 slave_t *s = kmalloc(sizeof(*s), GFP_KERNEL);
 422                                 equalizer_t *eql = netdev_priv(master_dev);
 423                                 int ret;
 424
 425                                 if (!s) {
 426                                         dev_put(slave_dev);
 427                                         return -ENOMEM;
 428                                 }
 429
 430                                 memset(s, 0, sizeof(*s));
 431                                 s->dev = slave_dev;
 432                                 s->priority = srq.priority;
 433                                 s->priority_bps = srq.priority;
 434                                 s->priority_Bps = srq.priority / 8;
 435
 436                                 spin_lock_bh(&eql->queue.lock);
 437                                 ret = __eql_insert_slave(&eql->queue, s);
 438                                 if (ret) {
 439                                         dev_put(slave_dev);
 440                                         kfree(s);
 441                                 }
 442                                 spin_unlock_bh(&eql->queue.lock);
 443
 444                                 return ret;
 445                         }
 446                 }
 447                 dev_put(slave_dev);
 448         }
 449
 450         return -EINVAL;
 451 }
 452
 453 static int eql_emancipate(struct net_device *master_dev, slaving_request_t __user *srqp)
 454 {
 455         equalizer_t *eql = netdev_priv(master_dev);
 456         struct net_device *slave_dev;
 457         slaving_request_t srq;
 458         int ret;
 459
 460         if (copy_from_user(&srq, srqp, sizeof (slaving_request_t)))
 461                 return -EFAULT;
 462
 463         slave_dev = dev_get_by_name(&init_net, srq.slave_name);
 464         ret = -EINVAL;
 465         if (slave_dev) {
 466                 spin_lock_bh(&eql->queue.lock);
 467
 468                 if (eql_is_slave(slave_dev)) {
 469                         slave_t *slave = __eql_find_slave_dev(&eql->queue,
 470                                                               slave_dev);
 471
 472                         if (slave) {
 473                                 eql_kill_one_slave(&eql->queue, slave);
 474                                 ret = 0;
 475                         }
 476                 }
 477                 dev_put(slave_dev);
 478
 479                 spin_unlock_bh(&eql->queue.lock);
 480         }
 481
 482         return ret;
 483 }
 484
 485 static int eql_g_slave_cfg(struct net_device *dev, slave_config_t __user *scp)
 486 {
 487         equalizer_t *eql = netdev_priv(dev);
 488         slave_t *slave;
 489         struct net_device *slave_dev;
 490         slave_config_t sc;
 491         int ret;
 492
 493         if (copy_from_user(&sc, scp, sizeof (slave_config_t)))
 494                 return -EFAULT;
 495
 496         slave_dev = dev_get_by_name(&init_net, sc.slave_name);
 497         if (!slave_dev)
 498                 return -ENODEV;
 499
 500         ret = -EINVAL;
 501
 502         spin_lock_bh(&eql->queue.lock);
 503         if (eql_is_slave(slave_dev)) {
 504                 slave = __eql_find_slave_dev(&eql->queue, slave_dev);
 505                 if (slave) {
 506                         sc.priority = slave->priority;
 507                         ret = 0;
 508                 }
 509         }
 510         spin_unlock_bh(&eql->queue.lock);
 511
 512         dev_put(slave_dev);
 513
 514         if (!ret && copy_to_user(scp, &sc, sizeof (slave_config_t)))
 515                 ret = -EFAULT;
 516
 517         return ret;
 518 }
 519
 520 static int eql_s_slave_cfg(struct net_device *dev, slave_config_t __user *scp)
 521 {
 522         slave_t *slave;
 523         equalizer_t *eql;
 524         struct net_device *slave_dev;
 525         slave_config_t sc;
 526         int ret;
 527
 528         if (copy_from_user(&sc, scp, sizeof (slave_config_t)))
 529                 return -EFAULT;
 530
 531         slave_dev = dev_get_by_name(&init_net, sc.slave_name);
 532         if (!slave_dev)
 533                 return -ENODEV;
 534
 535         ret = -EINVAL;
 536
 537         eql = netdev_priv(dev);
 538         spin_lock_bh(&eql->queue.lock);
 539         if (eql_is_slave(slave_dev)) {
 540                 slave = __eql_find_slave_dev(&eql->queue, slave_dev);
 541                 if (slave) {
 542                         slave->priority = sc.priority;
 543                         slave->priority_bps = sc.priority;
 544                         slave->priority_Bps = sc.priority / 8;
 545                         ret = 0;
 546                 }
 547         }
 548         spin_unlock_bh(&eql->queue.lock);
 549
 550         dev_put(slave_dev);
 551
 552         return ret;
 553 }
 554
 555 static int eql_g_master_cfg(struct net_device *dev, master_config_t __user *mcp)
 556 {
 557         equalizer_t *eql;
 558         master_config_t mc;
 559
 560         memset(&mc, 0, sizeof(master_config_t));
 561
 562         if (eql_is_master(dev)) {
 563                 eql = netdev_priv(dev);
 564                 mc.max_slaves = eql->max_slaves;
 565                 mc.min_slaves = eql->min_slaves;
 566                 if (copy_to_user(mcp, &mc, sizeof (master_config_t)))
 567                         return -EFAULT;
 568                 return 0;
 569         }
 570         return -EINVAL;
 571 }
 572
 573 static int eql_s_master_cfg(struct net_device *dev, master_config_t __user *mcp)
 574 {
 575         equalizer_t *eql;
 576         master_config_t mc;
 577
 578         if (copy_from_user(&mc, mcp, sizeof (master_config_t)))
 579                 return -EFAULT;
 580
 581         if (eql_is_master(dev)) {
 582                 eql = netdev_priv(dev);
 583                 eql->max_slaves = mc.max_slaves;
 584                 eql->min_slaves = mc.min_slaves;
 585                 return 0;
 586         }
 587         return -EINVAL;
 588 }
 589
 590 static struct net_device *dev_eql;
 591
 592 static int __init eql_init_module(void)
 593 {
 594         int err;
 595
 596         pr_info("%s\n", version);
 597
 598         dev_eql = alloc_netdev(sizeof(equalizer_t), "eql", eql_setup);
 599         if (!dev_eql)
 600                 return -ENOMEM;
 601
 602         err = register_netdev(dev_eql);
 603         if (err)
 604                 free_netdev(dev_eql);
 605         return err;
 606 }
 607
 608 static void __exit eql_cleanup_module(void)
 609 {
 610         unregister_netdev(dev_eql);
 611         free_netdev(dev_eql);
 612 }
 613
 614 module_init(eql_init_module);
 615 module_exit(eql_cleanup_module);
 616 MODULE_LICENSE("GPL");