xref: /openbmc/linux/drivers/net/eql.c (revision 22246614)
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 #include <net/net_namespace.h>
120 
121 #include <linux/if.h>
122 #include <linux/if_arp.h>
123 #include <linux/if_eql.h>
124 
125 #include <asm/uaccess.h>
126 
127 static int eql_open(struct net_device *dev);
128 static int eql_close(struct net_device *dev);
129 static int eql_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd);
130 static int eql_slave_xmit(struct sk_buff *skb, 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 	init_timer(&eql->timer);
170 	eql->timer.data     	= (unsigned long) eql;
171 	eql->timer.expires  	= jiffies + EQL_DEFAULT_RESCHED_IVAL;
172 	eql->timer.function 	= eql_timer;
173 
174 	spin_lock_init(&eql->queue.lock);
175 	INIT_LIST_HEAD(&eql->queue.all_slaves);
176 	eql->queue.master_dev	= dev;
177 
178 	dev->open		= eql_open;
179 	dev->stop		= eql_close;
180 	dev->do_ioctl		= eql_ioctl;
181 	dev->hard_start_xmit	= eql_slave_xmit;
182 
183 	/*
184 	 *	Now we undo some of the things that eth_setup does
185 	 * 	that we don't like
186 	 */
187 
188 	dev->mtu        	= EQL_DEFAULT_MTU;	/* set to 576 in if_eql.h */
189 	dev->flags      	= IFF_MASTER;
190 
191 	dev->type       	= ARPHRD_SLIP;
192 	dev->tx_queue_len 	= 5;		/* Hands them off fast */
193 }
194 
195 static int eql_open(struct net_device *dev)
196 {
197 	equalizer_t *eql = netdev_priv(dev);
198 
199 	/* XXX We should force this off automatically for the user. */
200 	printk(KERN_INFO "%s: remember to turn off Van-Jacobson compression on "
201 	       "your slave devices.\n", dev->name);
202 
203 	BUG_ON(!list_empty(&eql->queue.all_slaves));
204 
205 	eql->min_slaves = 1;
206 	eql->max_slaves = EQL_DEFAULT_MAX_SLAVES; /* 4 usually... */
207 
208 	add_timer(&eql->timer);
209 
210 	return 0;
211 }
212 
213 static void eql_kill_one_slave(slave_queue_t *queue, slave_t *slave)
214 {
215 	list_del(&slave->list);
216 	queue->num_slaves--;
217 	slave->dev->flags &= ~IFF_SLAVE;
218 	dev_put(slave->dev);
219 	kfree(slave);
220 }
221 
222 static void eql_kill_slave_queue(slave_queue_t *queue)
223 {
224 	struct list_head *head, *tmp, *this;
225 
226 	spin_lock_bh(&queue->lock);
227 
228 	head = &queue->all_slaves;
229 	list_for_each_safe(this, tmp, head) {
230 		slave_t *s = list_entry(this, slave_t, list);
231 
232 		eql_kill_one_slave(queue, s);
233 	}
234 
235 	spin_unlock_bh(&queue->lock);
236 }
237 
238 static int eql_close(struct net_device *dev)
239 {
240 	equalizer_t *eql = netdev_priv(dev);
241 
242 	/*
243 	 *	The timer has to be stopped first before we start hacking away
244 	 *	at the data structure it scans every so often...
245 	 */
246 
247 	del_timer_sync(&eql->timer);
248 
249 	eql_kill_slave_queue(&eql->queue);
250 
251 	return 0;
252 }
253 
254 static int eql_enslave(struct net_device *dev,  slaving_request_t __user *srq);
255 static int eql_emancipate(struct net_device *dev, slaving_request_t __user *srq);
256 
257 static int eql_g_slave_cfg(struct net_device *dev, slave_config_t __user *sc);
258 static int eql_s_slave_cfg(struct net_device *dev, slave_config_t __user *sc);
259 
260 static int eql_g_master_cfg(struct net_device *dev, master_config_t __user *mc);
261 static int eql_s_master_cfg(struct net_device *dev, master_config_t __user *mc);
262 
263 static int eql_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
264 {
265 	if (cmd != EQL_GETMASTRCFG && cmd != EQL_GETSLAVECFG &&
266 	    !capable(CAP_NET_ADMIN))
267 	  	return -EPERM;
268 
269 	switch (cmd) {
270 		case EQL_ENSLAVE:
271 			return eql_enslave(dev, ifr->ifr_data);
272 		case EQL_EMANCIPATE:
273 			return eql_emancipate(dev, ifr->ifr_data);
274 		case EQL_GETSLAVECFG:
275 			return eql_g_slave_cfg(dev, ifr->ifr_data);
276 		case EQL_SETSLAVECFG:
277 			return eql_s_slave_cfg(dev, ifr->ifr_data);
278 		case EQL_GETMASTRCFG:
279 			return eql_g_master_cfg(dev, ifr->ifr_data);
280 		case EQL_SETMASTRCFG:
281 			return eql_s_master_cfg(dev, ifr->ifr_data);
282 		default:
283 			return -EOPNOTSUPP;
284 	};
285 }
286 
287 /* queue->lock must be held */
288 static slave_t *__eql_schedule_slaves(slave_queue_t *queue)
289 {
290 	unsigned long best_load = ~0UL;
291 	struct list_head *this, *tmp, *head;
292 	slave_t *best_slave;
293 
294 	best_slave = NULL;
295 
296 	/* Make a pass to set the best slave. */
297 	head = &queue->all_slaves;
298 	list_for_each_safe(this, tmp, head) {
299 		slave_t *slave = list_entry(this, slave_t, list);
300 		unsigned long slave_load, bytes_queued, priority_Bps;
301 
302 		/* Go through the slave list once, updating best_slave
303 		 * whenever a new best_load is found.
304 		 */
305 		bytes_queued = slave->bytes_queued;
306 		priority_Bps = slave->priority_Bps;
307 		if ((slave->dev->flags & IFF_UP) == IFF_UP) {
308 			slave_load = (~0UL - (~0UL / 2)) -
309 				(priority_Bps) + bytes_queued * 8;
310 
311 			if (slave_load < best_load) {
312 				best_load = slave_load;
313 				best_slave = slave;
314 			}
315 		} else {
316 			/* We found a dead slave, kill it. */
317 			eql_kill_one_slave(queue, slave);
318 		}
319 	}
320 	return best_slave;
321 }
322 
323 static int eql_slave_xmit(struct sk_buff *skb, struct net_device *dev)
324 {
325 	equalizer_t *eql = netdev_priv(dev);
326 	slave_t *slave;
327 
328 	spin_lock(&eql->queue.lock);
329 
330 	slave = __eql_schedule_slaves(&eql->queue);
331 	if (slave) {
332 		struct net_device *slave_dev = slave->dev;
333 
334 		skb->dev = slave_dev;
335 		skb->priority = 1;
336 		slave->bytes_queued += skb->len;
337 		dev_queue_xmit(skb);
338 		dev->stats.tx_packets++;
339 	} else {
340 		dev->stats.tx_dropped++;
341 		dev_kfree_skb(skb);
342 	}
343 
344 	spin_unlock(&eql->queue.lock);
345 
346 	return 0;
347 }
348 
349 /*
350  *	Private ioctl functions
351  */
352 
353 /* queue->lock must be held */
354 static slave_t *__eql_find_slave_dev(slave_queue_t *queue, struct net_device *dev)
355 {
356 	struct list_head *this, *head;
357 
358 	head = &queue->all_slaves;
359 	list_for_each(this, head) {
360 		slave_t *slave = list_entry(this, slave_t, list);
361 
362 		if (slave->dev == dev)
363 			return slave;
364 	}
365 
366 	return NULL;
367 }
368 
369 static inline int eql_is_full(slave_queue_t *queue)
370 {
371 	equalizer_t *eql = netdev_priv(queue->master_dev);
372 
373 	if (queue->num_slaves >= eql->max_slaves)
374 		return 1;
375 	return 0;
376 }
377 
378 /* queue->lock must be held */
379 static int __eql_insert_slave(slave_queue_t *queue, slave_t *slave)
380 {
381 	if (!eql_is_full(queue)) {
382 		slave_t *duplicate_slave = NULL;
383 
384 		duplicate_slave = __eql_find_slave_dev(queue, slave->dev);
385 		if (duplicate_slave)
386 			eql_kill_one_slave(queue, duplicate_slave);
387 
388 		list_add(&slave->list, &queue->all_slaves);
389 		queue->num_slaves++;
390 		slave->dev->flags |= IFF_SLAVE;
391 
392 		return 0;
393 	}
394 
395 	return -ENOSPC;
396 }
397 
398 static int eql_enslave(struct net_device *master_dev, slaving_request_t __user *srqp)
399 {
400 	struct net_device *slave_dev;
401 	slaving_request_t srq;
402 
403 	if (copy_from_user(&srq, srqp, sizeof (slaving_request_t)))
404 		return -EFAULT;
405 
406 	slave_dev  = dev_get_by_name(&init_net, srq.slave_name);
407 	if (slave_dev) {
408 		if ((master_dev->flags & IFF_UP) == IFF_UP) {
409 			/* slave is not a master & not already a slave: */
410 			if (!eql_is_master(slave_dev) &&
411 			    !eql_is_slave(slave_dev)) {
412 				slave_t *s = kmalloc(sizeof(*s), GFP_KERNEL);
413 				equalizer_t *eql = netdev_priv(master_dev);
414 				int ret;
415 
416 				if (!s) {
417 					dev_put(slave_dev);
418 					return -ENOMEM;
419 				}
420 
421 				memset(s, 0, sizeof(*s));
422 				s->dev = slave_dev;
423 				s->priority = srq.priority;
424 				s->priority_bps = srq.priority;
425 				s->priority_Bps = srq.priority / 8;
426 
427 				spin_lock_bh(&eql->queue.lock);
428 				ret = __eql_insert_slave(&eql->queue, s);
429 				if (ret) {
430 					dev_put(slave_dev);
431 					kfree(s);
432 				}
433 				spin_unlock_bh(&eql->queue.lock);
434 
435 				return ret;
436 			}
437 		}
438 		dev_put(slave_dev);
439 	}
440 
441 	return -EINVAL;
442 }
443 
444 static int eql_emancipate(struct net_device *master_dev, slaving_request_t __user *srqp)
445 {
446 	equalizer_t *eql = netdev_priv(master_dev);
447 	struct net_device *slave_dev;
448 	slaving_request_t srq;
449 	int ret;
450 
451 	if (copy_from_user(&srq, srqp, sizeof (slaving_request_t)))
452 		return -EFAULT;
453 
454 	slave_dev = dev_get_by_name(&init_net, srq.slave_name);
455 	ret = -EINVAL;
456 	if (slave_dev) {
457 		spin_lock_bh(&eql->queue.lock);
458 
459 		if (eql_is_slave(slave_dev)) {
460 			slave_t *slave = __eql_find_slave_dev(&eql->queue,
461 							      slave_dev);
462 
463 			if (slave) {
464 				eql_kill_one_slave(&eql->queue, slave);
465 				ret = 0;
466 			}
467 		}
468 		dev_put(slave_dev);
469 
470 		spin_unlock_bh(&eql->queue.lock);
471 	}
472 
473 	return ret;
474 }
475 
476 static int eql_g_slave_cfg(struct net_device *dev, slave_config_t __user *scp)
477 {
478 	equalizer_t *eql = netdev_priv(dev);
479 	slave_t *slave;
480 	struct net_device *slave_dev;
481 	slave_config_t sc;
482 	int ret;
483 
484 	if (copy_from_user(&sc, scp, sizeof (slave_config_t)))
485 		return -EFAULT;
486 
487 	slave_dev = dev_get_by_name(&init_net, sc.slave_name);
488 	if (!slave_dev)
489 		return -ENODEV;
490 
491 	ret = -EINVAL;
492 
493 	spin_lock_bh(&eql->queue.lock);
494 	if (eql_is_slave(slave_dev)) {
495 		slave = __eql_find_slave_dev(&eql->queue, slave_dev);
496 		if (slave) {
497 			sc.priority = slave->priority;
498 			ret = 0;
499 		}
500 	}
501 	spin_unlock_bh(&eql->queue.lock);
502 
503 	dev_put(slave_dev);
504 
505 	if (!ret && copy_to_user(scp, &sc, sizeof (slave_config_t)))
506 		ret = -EFAULT;
507 
508 	return ret;
509 }
510 
511 static int eql_s_slave_cfg(struct net_device *dev, slave_config_t __user *scp)
512 {
513 	slave_t *slave;
514 	equalizer_t *eql;
515 	struct net_device *slave_dev;
516 	slave_config_t sc;
517 	int ret;
518 
519 	if (copy_from_user(&sc, scp, sizeof (slave_config_t)))
520 		return -EFAULT;
521 
522 	slave_dev = dev_get_by_name(&init_net, sc.slave_name);
523 	if (!slave_dev)
524 		return -ENODEV;
525 
526 	ret = -EINVAL;
527 
528 	eql = netdev_priv(dev);
529 	spin_lock_bh(&eql->queue.lock);
530 	if (eql_is_slave(slave_dev)) {
531 		slave = __eql_find_slave_dev(&eql->queue, slave_dev);
532 		if (slave) {
533 			slave->priority = sc.priority;
534 			slave->priority_bps = sc.priority;
535 			slave->priority_Bps = sc.priority / 8;
536 			ret = 0;
537 		}
538 	}
539 	spin_unlock_bh(&eql->queue.lock);
540 
541 	return ret;
542 }
543 
544 static int eql_g_master_cfg(struct net_device *dev, master_config_t __user *mcp)
545 {
546 	equalizer_t *eql;
547 	master_config_t mc;
548 
549 	if (eql_is_master(dev)) {
550 		eql = netdev_priv(dev);
551 		mc.max_slaves = eql->max_slaves;
552 		mc.min_slaves = eql->min_slaves;
553 		if (copy_to_user(mcp, &mc, sizeof (master_config_t)))
554 			return -EFAULT;
555 		return 0;
556 	}
557 	return -EINVAL;
558 }
559 
560 static int eql_s_master_cfg(struct net_device *dev, master_config_t __user *mcp)
561 {
562 	equalizer_t *eql;
563 	master_config_t mc;
564 
565 	if (copy_from_user(&mc, mcp, sizeof (master_config_t)))
566 		return -EFAULT;
567 
568 	if (eql_is_master(dev)) {
569 		eql = netdev_priv(dev);
570 		eql->max_slaves = mc.max_slaves;
571 		eql->min_slaves = mc.min_slaves;
572 		return 0;
573 	}
574 	return -EINVAL;
575 }
576 
577 static struct net_device *dev_eql;
578 
579 static int __init eql_init_module(void)
580 {
581 	int err;
582 
583 	printk(version);
584 
585 	dev_eql = alloc_netdev(sizeof(equalizer_t), "eql", eql_setup);
586 	if (!dev_eql)
587 		return -ENOMEM;
588 
589 	err = register_netdev(dev_eql);
590 	if (err)
591 		free_netdev(dev_eql);
592 	return err;
593 }
594 
595 static void __exit eql_cleanup_module(void)
596 {
597 	unregister_netdev(dev_eql);
598 	free_netdev(dev_eql);
599 }
600 
601 module_init(eql_init_module);
602 module_exit(eql_cleanup_module);
603 MODULE_LICENSE("GPL");
604