xref: /openbmc/linux/drivers/net/eql.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
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 
120 #include <linux/if.h>
121 #include <linux/if_arp.h>
122 #include <linux/if_eql.h>
123 
124 #include <asm/uaccess.h>
125 
126 static int eql_open(struct net_device *dev);
127 static int eql_close(struct net_device *dev);
128 static int eql_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd);
129 static int eql_slave_xmit(struct sk_buff *skb, struct net_device *dev);
130 static struct net_device_stats *eql_get_stats(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 	SET_MODULE_OWNER(dev);
170 
171 	init_timer(&eql->timer);
172 	eql->timer.data     	= (unsigned long) eql;
173 	eql->timer.expires  	= jiffies + EQL_DEFAULT_RESCHED_IVAL;
174 	eql->timer.function 	= eql_timer;
175 
176 	spin_lock_init(&eql->queue.lock);
177 	INIT_LIST_HEAD(&eql->queue.all_slaves);
178 	eql->queue.master_dev	= dev;
179 
180 	dev->open		= eql_open;
181 	dev->stop		= eql_close;
182 	dev->do_ioctl		= eql_ioctl;
183 	dev->hard_start_xmit	= eql_slave_xmit;
184 	dev->get_stats		= eql_get_stats;
185 
186 	/*
187 	 *	Now we undo some of the things that eth_setup does
188 	 * 	that we don't like
189 	 */
190 
191 	dev->mtu        	= EQL_DEFAULT_MTU;	/* set to 576 in if_eql.h */
192 	dev->flags      	= IFF_MASTER;
193 
194 	dev->type       	= ARPHRD_SLIP;
195 	dev->tx_queue_len 	= 5;		/* Hands them off fast */
196 }
197 
198 static int eql_open(struct net_device *dev)
199 {
200 	equalizer_t *eql = netdev_priv(dev);
201 
202 	/* XXX We should force this off automatically for the user. */
203 	printk(KERN_INFO "%s: remember to turn off Van-Jacobson compression on "
204 	       "your slave devices.\n", dev->name);
205 
206 	if (!list_empty(&eql->queue.all_slaves))
207 		BUG();
208 
209 	eql->min_slaves = 1;
210 	eql->max_slaves = EQL_DEFAULT_MAX_SLAVES; /* 4 usually... */
211 
212 	add_timer(&eql->timer);
213 
214 	return 0;
215 }
216 
217 static void eql_kill_one_slave(slave_queue_t *queue, slave_t *slave)
218 {
219 	list_del(&slave->list);
220 	queue->num_slaves--;
221 	slave->dev->flags &= ~IFF_SLAVE;
222 	dev_put(slave->dev);
223 	kfree(slave);
224 }
225 
226 static void eql_kill_slave_queue(slave_queue_t *queue)
227 {
228 	struct list_head *head, *tmp, *this;
229 
230 	spin_lock_bh(&queue->lock);
231 
232 	head = &queue->all_slaves;
233 	list_for_each_safe(this, tmp, head) {
234 		slave_t *s = list_entry(this, slave_t, list);
235 
236 		eql_kill_one_slave(queue, s);
237 	}
238 
239 	spin_unlock_bh(&queue->lock);
240 }
241 
242 static int eql_close(struct net_device *dev)
243 {
244 	equalizer_t *eql = netdev_priv(dev);
245 
246 	/*
247 	 *	The timer has to be stopped first before we start hacking away
248 	 *	at the data structure it scans every so often...
249 	 */
250 
251 	del_timer_sync(&eql->timer);
252 
253 	eql_kill_slave_queue(&eql->queue);
254 
255 	return 0;
256 }
257 
258 static int eql_enslave(struct net_device *dev,  slaving_request_t __user *srq);
259 static int eql_emancipate(struct net_device *dev, slaving_request_t __user *srq);
260 
261 static int eql_g_slave_cfg(struct net_device *dev, slave_config_t __user *sc);
262 static int eql_s_slave_cfg(struct net_device *dev, slave_config_t __user *sc);
263 
264 static int eql_g_master_cfg(struct net_device *dev, master_config_t __user *mc);
265 static int eql_s_master_cfg(struct net_device *dev, master_config_t __user *mc);
266 
267 static int eql_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
268 {
269 	if (cmd != EQL_GETMASTRCFG && cmd != EQL_GETSLAVECFG &&
270 	    !capable(CAP_NET_ADMIN))
271 	  	return -EPERM;
272 
273 	switch (cmd) {
274 		case EQL_ENSLAVE:
275 			return eql_enslave(dev, ifr->ifr_data);
276 		case EQL_EMANCIPATE:
277 			return eql_emancipate(dev, ifr->ifr_data);
278 		case EQL_GETSLAVECFG:
279 			return eql_g_slave_cfg(dev, ifr->ifr_data);
280 		case EQL_SETSLAVECFG:
281 			return eql_s_slave_cfg(dev, ifr->ifr_data);
282 		case EQL_GETMASTRCFG:
283 			return eql_g_master_cfg(dev, ifr->ifr_data);
284 		case EQL_SETMASTRCFG:
285 			return eql_s_master_cfg(dev, ifr->ifr_data);
286 		default:
287 			return -EOPNOTSUPP;
288 	};
289 }
290 
291 /* queue->lock must be held */
292 static slave_t *__eql_schedule_slaves(slave_queue_t *queue)
293 {
294 	unsigned long best_load = ~0UL;
295 	struct list_head *this, *tmp, *head;
296 	slave_t *best_slave;
297 
298 	best_slave = NULL;
299 
300 	/* Make a pass to set the best slave. */
301 	head = &queue->all_slaves;
302 	list_for_each_safe(this, tmp, head) {
303 		slave_t *slave = list_entry(this, slave_t, list);
304 		unsigned long slave_load, bytes_queued, priority_Bps;
305 
306 		/* Go through the slave list once, updating best_slave
307 		 * whenever a new best_load is found.
308 		 */
309 		bytes_queued = slave->bytes_queued;
310 		priority_Bps = slave->priority_Bps;
311 		if ((slave->dev->flags & IFF_UP) == IFF_UP) {
312 			slave_load = (~0UL - (~0UL / 2)) -
313 				(priority_Bps) + bytes_queued * 8;
314 
315 			if (slave_load < best_load) {
316 				best_load = slave_load;
317 				best_slave = slave;
318 			}
319 		} else {
320 			/* We found a dead slave, kill it. */
321 			eql_kill_one_slave(queue, slave);
322 		}
323 	}
324 	return best_slave;
325 }
326 
327 static int eql_slave_xmit(struct sk_buff *skb, struct net_device *dev)
328 {
329 	equalizer_t *eql = netdev_priv(dev);
330 	slave_t *slave;
331 
332 	spin_lock(&eql->queue.lock);
333 
334 	slave = __eql_schedule_slaves(&eql->queue);
335 	if (slave) {
336 		struct net_device *slave_dev = slave->dev;
337 
338 		skb->dev = slave_dev;
339 		skb->priority = 1;
340 		slave->bytes_queued += skb->len;
341 		dev_queue_xmit(skb);
342 		eql->stats.tx_packets++;
343 	} else {
344 		eql->stats.tx_dropped++;
345 		dev_kfree_skb(skb);
346 	}
347 
348 	spin_unlock(&eql->queue.lock);
349 
350 	return 0;
351 }
352 
353 static struct net_device_stats * eql_get_stats(struct net_device *dev)
354 {
355 	equalizer_t *eql = netdev_priv(dev);
356 	return &eql->stats;
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 != 0)
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(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(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(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(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 	return ret;
552 }
553 
554 static int eql_g_master_cfg(struct net_device *dev, master_config_t __user *mcp)
555 {
556 	equalizer_t *eql;
557 	master_config_t mc;
558 
559 	if (eql_is_master(dev)) {
560 		eql = netdev_priv(dev);
561 		mc.max_slaves = eql->max_slaves;
562 		mc.min_slaves = eql->min_slaves;
563 		if (copy_to_user(mcp, &mc, sizeof (master_config_t)))
564 			return -EFAULT;
565 		return 0;
566 	}
567 	return -EINVAL;
568 }
569 
570 static int eql_s_master_cfg(struct net_device *dev, master_config_t __user *mcp)
571 {
572 	equalizer_t *eql;
573 	master_config_t mc;
574 
575 	if (copy_from_user(&mc, mcp, sizeof (master_config_t)))
576 		return -EFAULT;
577 
578 	if (eql_is_master(dev)) {
579 		eql = netdev_priv(dev);
580 		eql->max_slaves = mc.max_slaves;
581 		eql->min_slaves = mc.min_slaves;
582 		return 0;
583 	}
584 	return -EINVAL;
585 }
586 
587 static struct net_device *dev_eql;
588 
589 static int __init eql_init_module(void)
590 {
591 	int err;
592 
593 	printk(version);
594 
595 	dev_eql = alloc_netdev(sizeof(equalizer_t), "eql", eql_setup);
596 	if (!dev_eql)
597 		return -ENOMEM;
598 
599 	err = register_netdev(dev_eql);
600 	if (err)
601 		free_netdev(dev_eql);
602 	return err;
603 }
604 
605 static void __exit eql_cleanup_module(void)
606 {
607 	unregister_netdev(dev_eql);
608 	free_netdev(dev_eql);
609 }
610 
611 module_init(eql_init_module);
612 module_exit(eql_cleanup_module);
613 MODULE_LICENSE("GPL");
614