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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 ([email protected])
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 [email protected], 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/compat.h>
117#include <linux/capability.h>
118#include <linux/module.h>
119#include <linux/kernel.h>
120#include <linux/init.h>
121#include <linux/slab.h>
122#include <linux/timer.h>
123#include <linux/netdevice.h>
124#include <net/net_namespace.h>
125
126#include <linux/if.h>
127#include <linux/if_arp.h>
128#include <linux/if_eql.h>
129#include <linux/pkt_sched.h>
130
131#include <linux/uaccess.h>
132
133static int eql_open(struct net_device *dev);
134static int eql_close(struct net_device *dev);
135static int eql_siocdevprivate(struct net_device *dev, struct ifreq *ifr,
136 void __user *data, int cmd);
137static netdev_tx_t eql_slave_xmit(struct sk_buff *skb, struct net_device *dev);
138
139#define eql_is_slave(dev) ((dev->flags & IFF_SLAVE) == IFF_SLAVE)
140#define eql_is_master(dev) ((dev->flags & IFF_MASTER) == IFF_MASTER)
141
142static void eql_kill_one_slave(slave_queue_t *queue, slave_t *slave);
143
144static void eql_timer(struct timer_list *t)
145{
146 equalizer_t *eql = timer_container_of(eql, t, timer);
147 struct list_head *this, *tmp, *head;
148
149 spin_lock(&eql->queue.lock);
150 head = &eql->queue.all_slaves;
151 list_for_each_safe(this, tmp, head) {
152 slave_t *slave = list_entry(this, slave_t, list);
153
154 if ((slave->dev->flags & IFF_UP) == IFF_UP) {
155 slave->bytes_queued -= slave->priority_Bps;
156 if (slave->bytes_queued < 0)
157 slave->bytes_queued = 0;
158 } else {
159 eql_kill_one_slave(&eql->queue, slave);
160 }
161
162 }
163 spin_unlock(&eql->queue.lock);
164
165 eql->timer.expires = jiffies + EQL_DEFAULT_RESCHED_IVAL;
166 add_timer(&eql->timer);
167}
168
169static const char version[] __initconst =
170 "Equalizer2002: Simon Janes ([email protected]) and David S. Miller ([email protected])";
171
172static const struct net_device_ops eql_netdev_ops = {
173 .ndo_open = eql_open,
174 .ndo_stop = eql_close,
175 .ndo_siocdevprivate = eql_siocdevprivate,
176 .ndo_start_xmit = eql_slave_xmit,
177};
178
179static void __init eql_setup(struct net_device *dev)
180{
181 equalizer_t *eql = netdev_priv(dev);
182
183 timer_setup(&eql->timer, eql_timer, 0);
184 eql->timer.expires = jiffies + EQL_DEFAULT_RESCHED_IVAL;
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 netif_keep_dst(dev);
203}
204
205static 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
223static 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 netdev_put(slave->dev, &slave->dev_tracker);
229 kfree(slave);
230}
231
232static 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
248static 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 timer_delete_sync(&eql->timer);
258
259 eql_kill_slave_queue(&eql->queue);
260
261 return 0;
262}
263
264static int eql_enslave(struct net_device *dev, slaving_request_t __user *srq);
265static int eql_emancipate(struct net_device *dev, slaving_request_t __user *srq);
266
267static int eql_g_slave_cfg(struct net_device *dev, slave_config_t __user *sc);
268static int eql_s_slave_cfg(struct net_device *dev, slave_config_t __user *sc);
269
270static int eql_g_master_cfg(struct net_device *dev, master_config_t __user *mc);
271static int eql_s_master_cfg(struct net_device *dev, master_config_t __user *mc);
272
273static int eql_siocdevprivate(struct net_device *dev, struct ifreq *ifr,
274 void __user *data, int cmd)
275{
276 if (cmd != EQL_GETMASTRCFG && cmd != EQL_GETSLAVECFG &&
277 !capable(CAP_NET_ADMIN))
278 return -EPERM;
279
280 if (in_compat_syscall()) /* to be implemented */
281 return -EOPNOTSUPP;
282
283 switch (cmd) {
284 case EQL_ENSLAVE:
285 return eql_enslave(dev, data);
286 case EQL_EMANCIPATE:
287 return eql_emancipate(dev, data);
288 case EQL_GETSLAVECFG:
289 return eql_g_slave_cfg(dev, data);
290 case EQL_SETSLAVECFG:
291 return eql_s_slave_cfg(dev, data);
292 case EQL_GETMASTRCFG:
293 return eql_g_master_cfg(dev, data);
294 case EQL_SETMASTRCFG:
295 return eql_s_master_cfg(dev, data);
296 default:
297 return -EOPNOTSUPP;
298 }
299}
300
301/* queue->lock must be held */
302static slave_t *__eql_schedule_slaves(slave_queue_t *queue)
303{
304 unsigned long best_load = ~0UL;
305 struct list_head *this, *tmp, *head;
306 slave_t *best_slave;
307
308 best_slave = NULL;
309
310 /* Make a pass to set the best slave. */
311 head = &queue->all_slaves;
312 list_for_each_safe(this, tmp, head) {
313 slave_t *slave = list_entry(this, slave_t, list);
314 unsigned long slave_load, bytes_queued, priority_Bps;
315
316 /* Go through the slave list once, updating best_slave
317 * whenever a new best_load is found.
318 */
319 bytes_queued = slave->bytes_queued;
320 priority_Bps = slave->priority_Bps;
321 if ((slave->dev->flags & IFF_UP) == IFF_UP) {
322 slave_load = (~0UL - (~0UL / 2)) -
323 (priority_Bps) + bytes_queued * 8;
324
325 if (slave_load < best_load) {
326 best_load = slave_load;
327 best_slave = slave;
328 }
329 } else {
330 /* We found a dead slave, kill it. */
331 eql_kill_one_slave(queue, slave);
332 }
333 }
334 return best_slave;
335}
336
337static netdev_tx_t eql_slave_xmit(struct sk_buff *skb, struct net_device *dev)
338{
339 equalizer_t *eql = netdev_priv(dev);
340 slave_t *slave;
341
342 spin_lock(&eql->queue.lock);
343
344 slave = __eql_schedule_slaves(&eql->queue);
345 if (slave) {
346 struct net_device *slave_dev = slave->dev;
347
348 skb->dev = slave_dev;
349 skb->priority = TC_PRIO_FILLER;
350 slave->bytes_queued += skb->len;
351 dev_queue_xmit(skb);
352 dev->stats.tx_packets++;
353 } else {
354 dev->stats.tx_dropped++;
355 dev_kfree_skb(skb);
356 }
357
358 spin_unlock(&eql->queue.lock);
359
360 return NETDEV_TX_OK;
361}
362
363/*
364 * Private ioctl functions
365 */
366
367/* queue->lock must be held */
368static slave_t *__eql_find_slave_dev(slave_queue_t *queue, struct net_device *dev)
369{
370 struct list_head *this, *head;
371
372 head = &queue->all_slaves;
373 list_for_each(this, head) {
374 slave_t *slave = list_entry(this, slave_t, list);
375
376 if (slave->dev == dev)
377 return slave;
378 }
379
380 return NULL;
381}
382
383static inline int eql_is_full(slave_queue_t *queue)
384{
385 equalizer_t *eql = netdev_priv(queue->master_dev);
386
387 if (queue->num_slaves >= eql->max_slaves)
388 return 1;
389 return 0;
390}
391
392/* queue->lock must be held */
393static int __eql_insert_slave(slave_queue_t *queue, slave_t *slave)
394{
395 if (!eql_is_full(queue)) {
396 slave_t *duplicate_slave = NULL;
397
398 duplicate_slave = __eql_find_slave_dev(queue, slave->dev);
399 if (duplicate_slave)
400 eql_kill_one_slave(queue, duplicate_slave);
401
402 netdev_hold(slave->dev, &slave->dev_tracker, GFP_ATOMIC);
403 list_add(&slave->list, &queue->all_slaves);
404 queue->num_slaves++;
405 slave->dev->flags |= IFF_SLAVE;
406
407 return 0;
408 }
409
410 return -ENOSPC;
411}
412
413static int eql_enslave(struct net_device *master_dev, slaving_request_t __user *srqp)
414{
415 struct net_device *slave_dev;
416 slaving_request_t srq;
417
418 if (copy_from_user(&srq, srqp, sizeof (slaving_request_t)))
419 return -EFAULT;
420
421 slave_dev = __dev_get_by_name(&init_net, srq.slave_name);
422 if (!slave_dev)
423 return -ENODEV;
424
425 if ((master_dev->flags & IFF_UP) == IFF_UP) {
426 /* slave is not a master & not already a slave: */
427 if (!eql_is_master(slave_dev) && !eql_is_slave(slave_dev)) {
428 slave_t *s = kzalloc_obj(*s);
429 equalizer_t *eql = netdev_priv(master_dev);
430 int ret;
431
432 if (!s)
433 return -ENOMEM;
434
435 s->dev = slave_dev;
436 s->priority = srq.priority;
437 s->priority_bps = srq.priority;
438 s->priority_Bps = srq.priority / 8;
439
440 spin_lock_bh(&eql->queue.lock);
441 ret = __eql_insert_slave(&eql->queue, s);
442 if (ret)
443 kfree(s);
444
445 spin_unlock_bh(&eql->queue.lock);
446
447 return ret;
448 }
449 }
450
451 return -EINVAL;
452}
453
454static 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 if (!slave_dev)
466 return -ENODEV;
467
468 ret = -EINVAL;
469 spin_lock_bh(&eql->queue.lock);
470 if (eql_is_slave(slave_dev)) {
471 slave_t *slave = __eql_find_slave_dev(&eql->queue, slave_dev);
472 if (slave) {
473 eql_kill_one_slave(&eql->queue, slave);
474 ret = 0;
475 }
476 }
477 spin_unlock_bh(&eql->queue.lock);
478
479 return ret;
480}
481
482static int eql_g_slave_cfg(struct net_device *dev, slave_config_t __user *scp)
483{
484 equalizer_t *eql = netdev_priv(dev);
485 slave_t *slave;
486 struct net_device *slave_dev;
487 slave_config_t sc;
488 int ret;
489
490 if (copy_from_user(&sc, scp, sizeof (slave_config_t)))
491 return -EFAULT;
492
493 slave_dev = __dev_get_by_name(&init_net, sc.slave_name);
494 if (!slave_dev)
495 return -ENODEV;
496
497 ret = -EINVAL;
498
499 spin_lock_bh(&eql->queue.lock);
500 if (eql_is_slave(slave_dev)) {
501 slave = __eql_find_slave_dev(&eql->queue, slave_dev);
502 if (slave) {
503 sc.priority = slave->priority;
504 ret = 0;
505 }
506 }
507 spin_unlock_bh(&eql->queue.lock);
508
509 if (!ret && copy_to_user(scp, &sc, sizeof (slave_config_t)))
510 ret = -EFAULT;
511
512 return ret;
513}
514
515static int eql_s_slave_cfg(struct net_device *dev, slave_config_t __user *scp)
516{
517 slave_t *slave;
518 equalizer_t *eql;
519 struct net_device *slave_dev;
520 slave_config_t sc;
521 int ret;
522
523 if (copy_from_user(&sc, scp, sizeof (slave_config_t)))
524 return -EFAULT;
525
526 slave_dev = __dev_get_by_name(&init_net, sc.slave_name);
527 if (!slave_dev)
528 return -ENODEV;
529
530 ret = -EINVAL;
531
532 eql = netdev_priv(dev);
533 spin_lock_bh(&eql->queue.lock);
534 if (eql_is_slave(slave_dev)) {
535 slave = __eql_find_slave_dev(&eql->queue, slave_dev);
536 if (slave) {
537 slave->priority = sc.priority;
538 slave->priority_bps = sc.priority;
539 slave->priority_Bps = sc.priority / 8;
540 ret = 0;
541 }
542 }
543 spin_unlock_bh(&eql->queue.lock);
544
545 return ret;
546}
547
548static int eql_g_master_cfg(struct net_device *dev, master_config_t __user *mcp)
549{
550 equalizer_t *eql;
551 master_config_t mc;
552
553 memset(&mc, 0, sizeof(master_config_t));
554
555 if (eql_is_master(dev)) {
556 eql = netdev_priv(dev);
557 mc.max_slaves = eql->max_slaves;
558 mc.min_slaves = eql->min_slaves;
559 if (copy_to_user(mcp, &mc, sizeof (master_config_t)))
560 return -EFAULT;
561 return 0;
562 }
563 return -EINVAL;
564}
565
566static int eql_s_master_cfg(struct net_device *dev, master_config_t __user *mcp)
567{
568 equalizer_t *eql;
569 master_config_t mc;
570
571 if (copy_from_user(&mc, mcp, sizeof (master_config_t)))
572 return -EFAULT;
573
574 if (eql_is_master(dev)) {
575 eql = netdev_priv(dev);
576 eql->max_slaves = mc.max_slaves;
577 eql->min_slaves = mc.min_slaves;
578 return 0;
579 }
580 return -EINVAL;
581}
582
583static struct net_device *dev_eql;
584
585static int __init eql_init_module(void)
586{
587 int err;
588
589 pr_info("%s\n", version);
590
591 dev_eql = alloc_netdev(sizeof(equalizer_t), "eql", NET_NAME_UNKNOWN,
592 eql_setup);
593 if (!dev_eql)
594 return -ENOMEM;
595
596 err = register_netdev(dev_eql);
597 if (err)
598 free_netdev(dev_eql);
599 return err;
600}
601
602static void __exit eql_cleanup_module(void)
603{
604 unregister_netdev(dev_eql);
605 free_netdev(dev_eql);
606}
607
608module_init(eql_init_module);
609module_exit(eql_cleanup_module);
610MODULE_DESCRIPTION("Equalizer Load-balancer for serial network interfaces");
611MODULE_LICENSE("GPL");