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