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[PATCH] Fix comment to synchronize_sched()
[linux-2.6.22.y-op.git] / net / sched / sch_teql.c
blob79b8ef34c6e4c9b14d5d877ba64f0a496701e316
1 /* net/sched/sch_teql.c "True" (or "trivial") link equalizer.
2 *
3 * This program is free software; you can redistribute it and/or
4 * modify it under the terms of the GNU General Public License
5 * as published by the Free Software Foundation; either version
6 * 2 of the License, or (at your option) any later version.
7 *
8 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
9 */
10
11 #include <linux/module.h>
12 #include <asm/uaccess.h>
13 #include <asm/system.h>
14 #include <linux/bitops.h>
15 #include <linux/types.h>
16 #include <linux/kernel.h>
17 #include <linux/sched.h>
18 #include <linux/string.h>
19 #include <linux/mm.h>
20 #include <linux/socket.h>
21 #include <linux/sockios.h>
22 #include <linux/in.h>
23 #include <linux/errno.h>
24 #include <linux/interrupt.h>
25 #include <linux/if_arp.h>
26 #include <linux/if_ether.h>
27 #include <linux/inet.h>
28 #include <linux/netdevice.h>
29 #include <linux/etherdevice.h>
30 #include <linux/notifier.h>
31 #include <linux/init.h>
32 #include <net/ip.h>
33 #include <net/route.h>
34 #include <linux/skbuff.h>
35 #include <linux/moduleparam.h>
36 #include <net/sock.h>
37 #include <net/pkt_sched.h>
38
39 /*
40 How to setup it.
41 ----------------
42
43 After loading this module you will find a new device teqlN
44 and new qdisc with the same name. To join a slave to the equalizer
45 you should just set this qdisc on a device f.e.
46
47 # tc qdisc add dev eth0 root teql0
48 # tc qdisc add dev eth1 root teql0
49
50 That's all. Full PnP 8)
51
52 Applicability.
53 --------------
54
55 1. Slave devices MUST be active devices, i.e., they must raise the tbusy
56 signal and generate EOI events. If you want to equalize virtual devices
57 like tunnels, use a normal eql device.
58 2. This device puts no limitations on physical slave characteristics
59 f.e. it will equalize 9600baud line and 100Mb ethernet perfectly :-)
60 Certainly, large difference in link speeds will make the resulting
61 eqalized link unusable, because of huge packet reordering.
62 I estimate an upper useful difference as ~10 times.
63 3. If the slave requires address resolution, only protocols using
64 neighbour cache (IPv4/IPv6) will work over the equalized link.
65 Other protocols are still allowed to use the slave device directly,
66 which will not break load balancing, though native slave
67 traffic will have the highest priority. */
68
69 struct teql_master
70 {
71 struct Qdisc_ops qops;
72 struct net_device *dev;
73 struct Qdisc *slaves;
74 struct list_head master_list;
75 struct net_device_stats stats;
76 };
77
78 struct teql_sched_data
79 {
80 struct Qdisc *next;
81 struct teql_master *m;
82 struct neighbour *ncache;
83 struct sk_buff_head q;
84 };
85
86 #define NEXT_SLAVE(q) (((struct teql_sched_data*)qdisc_priv(q))->next)
87
88 #define FMASK (IFF_BROADCAST|IFF_POINTOPOINT|IFF_BROADCAST)
89
90 /* "teql*" qdisc routines */
91
92 static int
93 teql_enqueue(struct sk_buff *skb, struct Qdisc* sch)
94 {
95 struct net_device *dev = sch->dev;
96 struct teql_sched_data *q = qdisc_priv(sch);
97
98 __skb_queue_tail(&q->q, skb);
99 if (q->q.qlen <= dev->tx_queue_len) {
100 sch->bstats.bytes += skb->len;
101 sch->bstats.packets++;
102 return 0;
103 }
104
105 __skb_unlink(skb, &q->q);
106 kfree_skb(skb);
107 sch->qstats.drops++;
108 return NET_XMIT_DROP;
109 }
110
111 static int
112 teql_requeue(struct sk_buff *skb, struct Qdisc* sch)
113 {
114 struct teql_sched_data *q = qdisc_priv(sch);
115
116 __skb_queue_head(&q->q, skb);
117 sch->qstats.requeues++;
118 return 0;
119 }
120
121 static struct sk_buff *
122 teql_dequeue(struct Qdisc* sch)
123 {
124 struct teql_sched_data *dat = qdisc_priv(sch);
125 struct sk_buff *skb;
126
127 skb = __skb_dequeue(&dat->q);
128 if (skb == NULL) {
129 struct net_device *m = dat->m->dev->qdisc->dev;
130 if (m) {
131 dat->m->slaves = sch;
132 netif_wake_queue(m);
133 }
134 }
135 sch->q.qlen = dat->q.qlen + dat->m->dev->qdisc->q.qlen;
136 return skb;
137 }
138
139 static __inline__ void
140 teql_neigh_release(struct neighbour *n)
141 {
142 if (n)
143 neigh_release(n);
144 }
145
146 static void
147 teql_reset(struct Qdisc* sch)
148 {
149 struct teql_sched_data *dat = qdisc_priv(sch);
150
151 skb_queue_purge(&dat->q);
152 sch->q.qlen = 0;
153 teql_neigh_release(xchg(&dat->ncache, NULL));
154 }
155
156 static void
157 teql_destroy(struct Qdisc* sch)
158 {
159 struct Qdisc *q, *prev;
160 struct teql_sched_data *dat = qdisc_priv(sch);
161 struct teql_master *master = dat->m;
162
163 if ((prev = master->slaves) != NULL) {
164 do {
165 q = NEXT_SLAVE(prev);
166 if (q == sch) {
167 NEXT_SLAVE(prev) = NEXT_SLAVE(q);
168 if (q == master->slaves) {
169 master->slaves = NEXT_SLAVE(q);
170 if (q == master->slaves) {
171 master->slaves = NULL;
172 spin_lock_bh(&master->dev->queue_lock);
173 qdisc_reset(master->dev->qdisc);
174 spin_unlock_bh(&master->dev->queue_lock);
175 }
176 }
177 skb_queue_purge(&dat->q);
178 teql_neigh_release(xchg(&dat->ncache, NULL));
179 break;
180 }
181
182 } while ((prev = q) != master->slaves);
183 }
184 }
185
186 static int teql_qdisc_init(struct Qdisc *sch, struct rtattr *opt)
187 {
188 struct net_device *dev = sch->dev;
189 struct teql_master *m = (struct teql_master*)sch->ops;
190 struct teql_sched_data *q = qdisc_priv(sch);
191
192 if (dev->hard_header_len > m->dev->hard_header_len)
193 return -EINVAL;
194
195 if (m->dev == dev)
196 return -ELOOP;
197
198 q->m = m;
199
200 skb_queue_head_init(&q->q);
201
202 if (m->slaves) {
203 if (m->dev->flags & IFF_UP) {
204 if ((m->dev->flags&IFF_POINTOPOINT && !(dev->flags&IFF_POINTOPOINT))
205 || (m->dev->flags&IFF_BROADCAST && !(dev->flags&IFF_BROADCAST))
206 || (m->dev->flags&IFF_MULTICAST && !(dev->flags&IFF_MULTICAST))
207 || dev->mtu < m->dev->mtu)
208 return -EINVAL;
209 } else {
210 if (!(dev->flags&IFF_POINTOPOINT))
211 m->dev->flags &= ~IFF_POINTOPOINT;
212 if (!(dev->flags&IFF_BROADCAST))
213 m->dev->flags &= ~IFF_BROADCAST;
214 if (!(dev->flags&IFF_MULTICAST))
215 m->dev->flags &= ~IFF_MULTICAST;
216 if (dev->mtu < m->dev->mtu)
217 m->dev->mtu = dev->mtu;
218 }
219 q->next = NEXT_SLAVE(m->slaves);
220 NEXT_SLAVE(m->slaves) = sch;
221 } else {
222 q->next = sch;
223 m->slaves = sch;
224 m->dev->mtu = dev->mtu;
225 m->dev->flags = (m->dev->flags&~FMASK)|(dev->flags&FMASK);
226 }
227 return 0;
228 }
229
230 /* "teql*" netdevice routines */
231
232 static int
233 __teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res, struct net_device *dev)
234 {
235 struct teql_sched_data *q = qdisc_priv(dev->qdisc);
236 struct neighbour *mn = skb->dst->neighbour;
237 struct neighbour *n = q->ncache;
238
239 if (mn->tbl == NULL)
240 return -EINVAL;
241 if (n && n->tbl == mn->tbl &&
242 memcmp(n->primary_key, mn->primary_key, mn->tbl->key_len) == 0) {
243 atomic_inc(&n->refcnt);
244 } else {
245 n = __neigh_lookup_errno(mn->tbl, mn->primary_key, dev);
246 if (IS_ERR(n))
247 return PTR_ERR(n);
248 }
249 if (neigh_event_send(n, skb_res) == 0) {
250 int err;
251 read_lock(&n->lock);
252 err = dev->hard_header(skb, dev, ntohs(skb->protocol), n->ha, NULL, skb->len);
253 read_unlock(&n->lock);
254 if (err < 0) {
255 neigh_release(n);
256 return -EINVAL;
257 }
258 teql_neigh_release(xchg(&q->ncache, n));
259 return 0;
260 }
261 neigh_release(n);
262 return (skb_res == NULL) ? -EAGAIN : 1;
263 }
264
265 static __inline__ int
266 teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res, struct net_device *dev)
267 {
268 if (dev->hard_header == NULL ||
269 skb->dst == NULL ||
270 skb->dst->neighbour == NULL)
271 return 0;
272 return __teql_resolve(skb, skb_res, dev);
273 }
274
275 static int teql_master_xmit(struct sk_buff *skb, struct net_device *dev)
276 {
277 struct teql_master *master = netdev_priv(dev);
278 struct Qdisc *start, *q;
279 int busy;
280 int nores;
281 int len = skb->len;
282 struct sk_buff *skb_res = NULL;
283
284 start = master->slaves;
285
286 restart:
287 nores = 0;
288 busy = 0;
289
290 if ((q = start) == NULL)
291 goto drop;
292
293 do {
294 struct net_device *slave = q->dev;
295
296 if (slave->qdisc_sleeping != q)
297 continue;
298 if (netif_queue_stopped(slave) || ! netif_running(slave)) {
299 busy = 1;
300 continue;
301 }
302
303 switch (teql_resolve(skb, skb_res, slave)) {
304 case 0:
305 if (spin_trylock(&slave->xmit_lock)) {
306 slave->xmit_lock_owner = smp_processor_id();
307 if (!netif_queue_stopped(slave) &&
308 slave->hard_start_xmit(skb, slave) == 0) {
309 slave->xmit_lock_owner = -1;
310 spin_unlock(&slave->xmit_lock);
311 master->slaves = NEXT_SLAVE(q);
312 netif_wake_queue(dev);
313 master->stats.tx_packets++;
314 master->stats.tx_bytes += len;
315 return 0;
316 }
317 slave->xmit_lock_owner = -1;
318 spin_unlock(&slave->xmit_lock);
319 }
320 if (netif_queue_stopped(dev))
321 busy = 1;
322 break;
323 case 1:
324 master->slaves = NEXT_SLAVE(q);
325 return 0;
326 default:
327 nores = 1;
328 break;
329 }
330 __skb_pull(skb, skb->nh.raw - skb->data);
331 } while ((q = NEXT_SLAVE(q)) != start);
332
333 if (nores && skb_res == NULL) {
334 skb_res = skb;
335 goto restart;
336 }
337
338 if (busy) {
339 netif_stop_queue(dev);
340 return 1;
341 }
342 master->stats.tx_errors++;
343
344 drop:
345 master->stats.tx_dropped++;
346 dev_kfree_skb(skb);
347 return 0;
348 }
349
350 static int teql_master_open(struct net_device *dev)
351 {
352 struct Qdisc * q;
353 struct teql_master *m = netdev_priv(dev);
354 int mtu = 0xFFFE;
355 unsigned flags = IFF_NOARP|IFF_MULTICAST;
356
357 if (m->slaves == NULL)
358 return -EUNATCH;
359
360 flags = FMASK;
361
362 q = m->slaves;
363 do {
364 struct net_device *slave = q->dev;
365
366 if (slave == NULL)
367 return -EUNATCH;
368
369 if (slave->mtu < mtu)
370 mtu = slave->mtu;
371 if (slave->hard_header_len > LL_MAX_HEADER)
372 return -EINVAL;
373
374 /* If all the slaves are BROADCAST, master is BROADCAST
375 If all the slaves are PtP, master is PtP
376 Otherwise, master is NBMA.
377 */
378 if (!(slave->flags&IFF_POINTOPOINT))
379 flags &= ~IFF_POINTOPOINT;
380 if (!(slave->flags&IFF_BROADCAST))
381 flags &= ~IFF_BROADCAST;
382 if (!(slave->flags&IFF_MULTICAST))
383 flags &= ~IFF_MULTICAST;
384 } while ((q = NEXT_SLAVE(q)) != m->slaves);
385
386 m->dev->mtu = mtu;
387 m->dev->flags = (m->dev->flags&~FMASK) | flags;
388 netif_start_queue(m->dev);
389 return 0;
390 }
391
392 static int teql_master_close(struct net_device *dev)
393 {
394 netif_stop_queue(dev);
395 return 0;
396 }
397
398 static struct net_device_stats *teql_master_stats(struct net_device *dev)
399 {
400 struct teql_master *m = netdev_priv(dev);
401 return &m->stats;
402 }
403
404 static int teql_master_mtu(struct net_device *dev, int new_mtu)
405 {
406 struct teql_master *m = netdev_priv(dev);
407 struct Qdisc *q;
408
409 if (new_mtu < 68)
410 return -EINVAL;
411
412 q = m->slaves;
413 if (q) {
414 do {
415 if (new_mtu > q->dev->mtu)
416 return -EINVAL;
417 } while ((q=NEXT_SLAVE(q)) != m->slaves);
418 }
419
420 dev->mtu = new_mtu;
421 return 0;
422 }
423
424 static __init void teql_master_setup(struct net_device *dev)
425 {
426 struct teql_master *master = netdev_priv(dev);
427 struct Qdisc_ops *ops = &master->qops;
428
429 master->dev = dev;
430 ops->priv_size = sizeof(struct teql_sched_data);
431
432 ops->enqueue = teql_enqueue;
433 ops->dequeue = teql_dequeue;
434 ops->requeue = teql_requeue;
435 ops->init = teql_qdisc_init;
436 ops->reset = teql_reset;
437 ops->destroy = teql_destroy;
438 ops->owner = THIS_MODULE;
439
440 dev->open = teql_master_open;
441 dev->hard_start_xmit = teql_master_xmit;
442 dev->stop = teql_master_close;
443 dev->get_stats = teql_master_stats;
444 dev->change_mtu = teql_master_mtu;
445 dev->type = ARPHRD_VOID;
446 dev->mtu = 1500;
447 dev->tx_queue_len = 100;
448 dev->flags = IFF_NOARP;
449 dev->hard_header_len = LL_MAX_HEADER;
450 SET_MODULE_OWNER(dev);
451 }
452
453 static LIST_HEAD(master_dev_list);
454 static int max_equalizers = 1;
455 module_param(max_equalizers, int, 0);
456 MODULE_PARM_DESC(max_equalizers, "Max number of link equalizers");
457
458 static int __init teql_init(void)
459 {
460 int i;
461 int err = -ENODEV;
462
463 for (i = 0; i < max_equalizers; i++) {
464 struct net_device *dev;
465 struct teql_master *master;
466
467 dev = alloc_netdev(sizeof(struct teql_master),
468 "teql%d", teql_master_setup);
469 if (!dev) {
470 err = -ENOMEM;
471 break;
472 }
473
474 if ((err = register_netdev(dev))) {
475 free_netdev(dev);
476 break;
477 }
478
479 master = netdev_priv(dev);
480
481 strlcpy(master->qops.id, dev->name, IFNAMSIZ);
482 err = register_qdisc(&master->qops);
483
484 if (err) {
485 unregister_netdev(dev);
486 free_netdev(dev);
487 break;
488 }
489
490 list_add_tail(&master->master_list, &master_dev_list);
491 }
492 return i ? 0 : err;
493 }
494
495 static void __exit teql_exit(void)
496 {
497 struct teql_master *master, *nxt;
498
499 list_for_each_entry_safe(master, nxt, &master_dev_list, master_list) {
500
501 list_del(&master->master_list);
502
503 unregister_qdisc(&master->qops);
504 unregister_netdev(master->dev);
505 free_netdev(master->dev);
506 }
507 }
508
509 module_init(teql_init);
510 module_exit(teql_exit);
511
512 MODULE_LICENSE("GPL");
linux v2.6.22.y-op