xref: /openbmc/linux/drivers/net/eql.c (revision 64c70b1c)
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 	BUG_ON(!list_empty(&eql->queue.all_slaves));
207 
208 	eql->min_slaves = 1;
209 	eql->max_slaves = EQL_DEFAULT_MAX_SLAVES; /* 4 usually... */
210 
211 	add_timer(&eql->timer);
212 
213 	return 0;
214 }
215 
216 static void eql_kill_one_slave(slave_queue_t *queue, slave_t *slave)
217 {
218 	list_del(&slave->list);
219 	queue->num_slaves--;
220 	slave->dev->flags &= ~IFF_SLAVE;
221 	dev_put(slave->dev);
222 	kfree(slave);
223 }
224 
225 static void eql_kill_slave_queue(slave_queue_t *queue)
226 {
227 	struct list_head *head, *tmp, *this;
228 
229 	spin_lock_bh(&queue->lock);
230 
231 	head = &queue->all_slaves;
232 	list_for_each_safe(this, tmp, head) {
233 		slave_t *s = list_entry(this, slave_t, list);
234 
235 		eql_kill_one_slave(queue, s);
236 	}
237 
238 	spin_unlock_bh(&queue->lock);
239 }
240 
241 static int eql_close(struct net_device *dev)
242 {
243 	equalizer_t *eql = netdev_priv(dev);
244 
245 	/*
246 	 *	The timer has to be stopped first before we start hacking away
247 	 *	at the data structure it scans every so often...
248 	 */
249 
250 	del_timer_sync(&eql->timer);
251 
252 	eql_kill_slave_queue(&eql->queue);
253 
254 	return 0;
255 }
256 
257 static int eql_enslave(struct net_device *dev,  slaving_request_t __user *srq);
258 static int eql_emancipate(struct net_device *dev, slaving_request_t __user *srq);
259 
260 static int eql_g_slave_cfg(struct net_device *dev, slave_config_t __user *sc);
261 static int eql_s_slave_cfg(struct net_device *dev, slave_config_t __user *sc);
262 
263 static int eql_g_master_cfg(struct net_device *dev, master_config_t __user *mc);
264 static int eql_s_master_cfg(struct net_device *dev, master_config_t __user *mc);
265 
266 static int eql_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
267 {
268 	if (cmd != EQL_GETMASTRCFG && cmd != EQL_GETSLAVECFG &&
269 	    !capable(CAP_NET_ADMIN))
270 	  	return -EPERM;
271 
272 	switch (cmd) {
273 		case EQL_ENSLAVE:
274 			return eql_enslave(dev, ifr->ifr_data);
275 		case EQL_EMANCIPATE:
276 			return eql_emancipate(dev, ifr->ifr_data);
277 		case EQL_GETSLAVECFG:
278 			return eql_g_slave_cfg(dev, ifr->ifr_data);
279 		case EQL_SETSLAVECFG:
280 			return eql_s_slave_cfg(dev, ifr->ifr_data);
281 		case EQL_GETMASTRCFG:
282 			return eql_g_master_cfg(dev, ifr->ifr_data);
283 		case EQL_SETMASTRCFG:
284 			return eql_s_master_cfg(dev, ifr->ifr_data);
285 		default:
286 			return -EOPNOTSUPP;
287 	};
288 }
289 
290 /* queue->lock must be held */
291 static slave_t *__eql_schedule_slaves(slave_queue_t *queue)
292 {
293 	unsigned long best_load = ~0UL;
294 	struct list_head *this, *tmp, *head;
295 	slave_t *best_slave;
296 
297 	best_slave = NULL;
298 
299 	/* Make a pass to set the best slave. */
300 	head = &queue->all_slaves;
301 	list_for_each_safe(this, tmp, head) {
302 		slave_t *slave = list_entry(this, slave_t, list);
303 		unsigned long slave_load, bytes_queued, priority_Bps;
304 
305 		/* Go through the slave list once, updating best_slave
306 		 * whenever a new best_load is found.
307 		 */
308 		bytes_queued = slave->bytes_queued;
309 		priority_Bps = slave->priority_Bps;
310 		if ((slave->dev->flags & IFF_UP) == IFF_UP) {
311 			slave_load = (~0UL - (~0UL / 2)) -
312 				(priority_Bps) + bytes_queued * 8;
313 
314 			if (slave_load < best_load) {
315 				best_load = slave_load;
316 				best_slave = slave;
317 			}
318 		} else {
319 			/* We found a dead slave, kill it. */
320 			eql_kill_one_slave(queue, slave);
321 		}
322 	}
323 	return best_slave;
324 }
325 
326 static int eql_slave_xmit(struct sk_buff *skb, struct net_device *dev)
327 {
328 	equalizer_t *eql = netdev_priv(dev);
329 	slave_t *slave;
330 
331 	spin_lock(&eql->queue.lock);
332 
333 	slave = __eql_schedule_slaves(&eql->queue);
334 	if (slave) {
335 		struct net_device *slave_dev = slave->dev;
336 
337 		skb->dev = slave_dev;
338 		skb->priority = 1;
339 		slave->bytes_queued += skb->len;
340 		dev_queue_xmit(skb);
341 		eql->stats.tx_packets++;
342 	} else {
343 		eql->stats.tx_dropped++;
344 		dev_kfree_skb(skb);
345 	}
346 
347 	spin_unlock(&eql->queue.lock);
348 
349 	return 0;
350 }
351 
352 static struct net_device_stats * eql_get_stats(struct net_device *dev)
353 {
354 	equalizer_t *eql = netdev_priv(dev);
355 	return &eql->stats;
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 != 0)
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(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(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(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(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 	return ret;
551 }
552 
553 static int eql_g_master_cfg(struct net_device *dev, master_config_t __user *mcp)
554 {
555 	equalizer_t *eql;
556 	master_config_t mc;
557 
558 	if (eql_is_master(dev)) {
559 		eql = netdev_priv(dev);
560 		mc.max_slaves = eql->max_slaves;
561 		mc.min_slaves = eql->min_slaves;
562 		if (copy_to_user(mcp, &mc, sizeof (master_config_t)))
563 			return -EFAULT;
564 		return 0;
565 	}
566 	return -EINVAL;
567 }
568 
569 static int eql_s_master_cfg(struct net_device *dev, master_config_t __user *mcp)
570 {
571 	equalizer_t *eql;
572 	master_config_t mc;
573 
574 	if (copy_from_user(&mc, mcp, sizeof (master_config_t)))
575 		return -EFAULT;
576 
577 	if (eql_is_master(dev)) {
578 		eql = netdev_priv(dev);
579 		eql->max_slaves = mc.max_slaves;
580 		eql->min_slaves = mc.min_slaves;
581 		return 0;
582 	}
583 	return -EINVAL;
584 }
585 
586 static struct net_device *dev_eql;
587 
588 static int __init eql_init_module(void)
589 {
590 	int err;
591 
592 	printk(version);
593 
594 	dev_eql = alloc_netdev(sizeof(equalizer_t), "eql", eql_setup);
595 	if (!dev_eql)
596 		return -ENOMEM;
597 
598 	err = register_netdev(dev_eql);
599 	if (err)
600 		free_netdev(dev_eql);
601 	return err;
602 }
603 
604 static void __exit eql_cleanup_module(void)
605 {
606 	unregister_netdev(dev_eql);
607 	free_netdev(dev_eql);
608 }
609 
610 module_init(eql_init_module);
611 module_exit(eql_cleanup_module);
612 MODULE_LICENSE("GPL");
613