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OMAP: Add new function to check wether there is irq pending
[linux-ginger.git] / net / sched / sch_teql.c
blob3b64182972312f183d4dbdd4d506d862c3df891f
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 <linux/types.h>
13 #include <linux/kernel.h>
14 #include <linux/string.h>
15 #include <linux/errno.h>
16 #include <linux/if_arp.h>
17 #include <linux/netdevice.h>
18 #include <linux/init.h>
19 #include <linux/skbuff.h>
20 #include <linux/moduleparam.h>
21 #include <net/dst.h>
22 #include <net/neighbour.h>
23 #include <net/pkt_sched.h>
24
25 /*
26 How to setup it.
27 ----------------
28
29 After loading this module you will find a new device teqlN
30 and new qdisc with the same name. To join a slave to the equalizer
31 you should just set this qdisc on a device f.e.
32
33 # tc qdisc add dev eth0 root teql0
34 # tc qdisc add dev eth1 root teql0
35
36 That's all. Full PnP 8)
37
38 Applicability.
39 --------------
40
41 1. Slave devices MUST be active devices, i.e., they must raise the tbusy
42 signal and generate EOI events. If you want to equalize virtual devices
43 like tunnels, use a normal eql device.
44 2. This device puts no limitations on physical slave characteristics
45 f.e. it will equalize 9600baud line and 100Mb ethernet perfectly :-)
46 Certainly, large difference in link speeds will make the resulting
47 eqalized link unusable, because of huge packet reordering.
48 I estimate an upper useful difference as ~10 times.
49 3. If the slave requires address resolution, only protocols using
50 neighbour cache (IPv4/IPv6) will work over the equalized link.
51 Other protocols are still allowed to use the slave device directly,
52 which will not break load balancing, though native slave
53 traffic will have the highest priority. */
54
55 struct teql_master
56 {
57 struct Qdisc_ops qops;
58 struct net_device *dev;
59 struct Qdisc *slaves;
60 struct list_head master_list;
61 struct net_device_stats stats;
62 };
63
64 struct teql_sched_data
65 {
66 struct Qdisc *next;
67 struct teql_master *m;
68 struct neighbour *ncache;
69 struct sk_buff_head q;
70 };
71
72 #define NEXT_SLAVE(q) (((struct teql_sched_data*)qdisc_priv(q))->next)
73
74 #define FMASK (IFF_BROADCAST|IFF_POINTOPOINT)
75
76 /* "teql*" qdisc routines */
77
78 static int
79 teql_enqueue(struct sk_buff *skb, struct Qdisc* sch)
80 {
81 struct net_device *dev = qdisc_dev(sch);
82 struct teql_sched_data *q = qdisc_priv(sch);
83
84 if (q->q.qlen < dev->tx_queue_len) {
85 __skb_queue_tail(&q->q, skb);
86 sch->bstats.bytes += qdisc_pkt_len(skb);
87 sch->bstats.packets++;
88 return 0;
89 }
90
91 kfree_skb(skb);
92 sch->qstats.drops++;
93 return NET_XMIT_DROP;
94 }
95
96 static struct sk_buff *
97 teql_dequeue(struct Qdisc* sch)
98 {
99 struct teql_sched_data *dat = qdisc_priv(sch);
100 struct netdev_queue *dat_queue;
101 struct sk_buff *skb;
102
103 skb = __skb_dequeue(&dat->q);
104 dat_queue = netdev_get_tx_queue(dat->m->dev, 0);
105 if (skb == NULL) {
106 struct net_device *m = qdisc_dev(dat_queue->qdisc);
107 if (m) {
108 dat->m->slaves = sch;
109 netif_wake_queue(m);
110 }
111 }
112 sch->q.qlen = dat->q.qlen + dat_queue->qdisc->q.qlen;
113 return skb;
114 }
115
116 static struct sk_buff *
117 teql_peek(struct Qdisc* sch)
118 {
119 /* teql is meant to be used as root qdisc */
120 return NULL;
121 }
122
123 static __inline__ void
124 teql_neigh_release(struct neighbour *n)
125 {
126 if (n)
127 neigh_release(n);
128 }
129
130 static void
131 teql_reset(struct Qdisc* sch)
132 {
133 struct teql_sched_data *dat = qdisc_priv(sch);
134
135 skb_queue_purge(&dat->q);
136 sch->q.qlen = 0;
137 teql_neigh_release(xchg(&dat->ncache, NULL));
138 }
139
140 static void
141 teql_destroy(struct Qdisc* sch)
142 {
143 struct Qdisc *q, *prev;
144 struct teql_sched_data *dat = qdisc_priv(sch);
145 struct teql_master *master = dat->m;
146
147 if ((prev = master->slaves) != NULL) {
148 do {
149 q = NEXT_SLAVE(prev);
150 if (q == sch) {
151 NEXT_SLAVE(prev) = NEXT_SLAVE(q);
152 if (q == master->slaves) {
153 master->slaves = NEXT_SLAVE(q);
154 if (q == master->slaves) {
155 struct netdev_queue *txq;
156 spinlock_t *root_lock;
157
158 txq = netdev_get_tx_queue(master->dev, 0);
159 master->slaves = NULL;
160
161 root_lock = qdisc_root_sleeping_lock(txq->qdisc);
162 spin_lock_bh(root_lock);
163 qdisc_reset(txq->qdisc);
164 spin_unlock_bh(root_lock);
165 }
166 }
167 skb_queue_purge(&dat->q);
168 teql_neigh_release(xchg(&dat->ncache, NULL));
169 break;
170 }
171
172 } while ((prev = q) != master->slaves);
173 }
174 }
175
176 static int teql_qdisc_init(struct Qdisc *sch, struct nlattr *opt)
177 {
178 struct net_device *dev = qdisc_dev(sch);
179 struct teql_master *m = (struct teql_master*)sch->ops;
180 struct teql_sched_data *q = qdisc_priv(sch);
181
182 if (dev->hard_header_len > m->dev->hard_header_len)
183 return -EINVAL;
184
185 if (m->dev == dev)
186 return -ELOOP;
187
188 q->m = m;
189
190 skb_queue_head_init(&q->q);
191
192 if (m->slaves) {
193 if (m->dev->flags & IFF_UP) {
194 if ((m->dev->flags&IFF_POINTOPOINT && !(dev->flags&IFF_POINTOPOINT))
195 || (m->dev->flags&IFF_BROADCAST && !(dev->flags&IFF_BROADCAST))
196 || (m->dev->flags&IFF_MULTICAST && !(dev->flags&IFF_MULTICAST))
197 || dev->mtu < m->dev->mtu)
198 return -EINVAL;
199 } else {
200 if (!(dev->flags&IFF_POINTOPOINT))
201 m->dev->flags &= ~IFF_POINTOPOINT;
202 if (!(dev->flags&IFF_BROADCAST))
203 m->dev->flags &= ~IFF_BROADCAST;
204 if (!(dev->flags&IFF_MULTICAST))
205 m->dev->flags &= ~IFF_MULTICAST;
206 if (dev->mtu < m->dev->mtu)
207 m->dev->mtu = dev->mtu;
208 }
209 q->next = NEXT_SLAVE(m->slaves);
210 NEXT_SLAVE(m->slaves) = sch;
211 } else {
212 q->next = sch;
213 m->slaves = sch;
214 m->dev->mtu = dev->mtu;
215 m->dev->flags = (m->dev->flags&~FMASK)|(dev->flags&FMASK);
216 }
217 return 0;
218 }
219
220
221 static int
222 __teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res, struct net_device *dev)
223 {
224 struct netdev_queue *dev_queue = netdev_get_tx_queue(dev, 0);
225 struct teql_sched_data *q = qdisc_priv(dev_queue->qdisc);
226 struct neighbour *mn = skb->dst->neighbour;
227 struct neighbour *n = q->ncache;
228
229 if (mn->tbl == NULL)
230 return -EINVAL;
231 if (n && n->tbl == mn->tbl &&
232 memcmp(n->primary_key, mn->primary_key, mn->tbl->key_len) == 0) {
233 atomic_inc(&n->refcnt);
234 } else {
235 n = __neigh_lookup_errno(mn->tbl, mn->primary_key, dev);
236 if (IS_ERR(n))
237 return PTR_ERR(n);
238 }
239 if (neigh_event_send(n, skb_res) == 0) {
240 int err;
241
242 read_lock(&n->lock);
243 err = dev_hard_header(skb, dev, ntohs(skb->protocol),
244 n->ha, NULL, skb->len);
245 read_unlock(&n->lock);
246
247 if (err < 0) {
248 neigh_release(n);
249 return -EINVAL;
250 }
251 teql_neigh_release(xchg(&q->ncache, n));
252 return 0;
253 }
254 neigh_release(n);
255 return (skb_res == NULL) ? -EAGAIN : 1;
256 }
257
258 static inline int teql_resolve(struct sk_buff *skb,
259 struct sk_buff *skb_res, struct net_device *dev)
260 {
261 struct netdev_queue *txq = netdev_get_tx_queue(dev, 0);
262 if (txq->qdisc == &noop_qdisc)
263 return -ENODEV;
264
265 if (dev->header_ops == NULL ||
266 skb->dst == NULL ||
267 skb->dst->neighbour == NULL)
268 return 0;
269 return __teql_resolve(skb, skb_res, dev);
270 }
271
272 static int teql_master_xmit(struct sk_buff *skb, struct net_device *dev)
273 {
274 struct teql_master *master = netdev_priv(dev);
275 struct Qdisc *start, *q;
276 int busy;
277 int nores;
278 int subq = skb_get_queue_mapping(skb);
279 struct sk_buff *skb_res = NULL;
280
281 start = master->slaves;
282
283 restart:
284 nores = 0;
285 busy = 0;
286
287 if ((q = start) == NULL)
288 goto drop;
289
290 do {
291 struct net_device *slave = qdisc_dev(q);
292 struct netdev_queue *slave_txq = netdev_get_tx_queue(slave, 0);
293 const struct net_device_ops *slave_ops = slave->netdev_ops;
294
295 if (slave_txq->qdisc_sleeping != q)
296 continue;
297 if (__netif_subqueue_stopped(slave, subq) ||
298 !netif_running(slave)) {
299 busy = 1;
300 continue;
301 }
302
303 switch (teql_resolve(skb, skb_res, slave)) {
304 case 0:
305 if (__netif_tx_trylock(slave_txq)) {
306 unsigned int length = qdisc_pkt_len(skb);
307
308 if (!netif_tx_queue_stopped(slave_txq) &&
309 !netif_tx_queue_frozen(slave_txq) &&
310 slave_ops->ndo_start_xmit(skb, slave) == 0) {
311 __netif_tx_unlock(slave_txq);
312 master->slaves = NEXT_SLAVE(q);
313 netif_wake_queue(dev);
314 master->stats.tx_packets++;
315 master->stats.tx_bytes += length;
316 return 0;
317 }
318 __netif_tx_unlock(slave_txq);
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_network_offset(skb));
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 = qdisc_dev(q);
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 > qdisc_dev(q)->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 const struct net_device_ops teql_netdev_ops = {
425 .ndo_open = teql_master_open,
426 .ndo_stop = teql_master_close,
427 .ndo_start_xmit = teql_master_xmit,
428 .ndo_get_stats = teql_master_stats,
429 .ndo_change_mtu = teql_master_mtu,
430 };
431
432 static __init void teql_master_setup(struct net_device *dev)
433 {
434 struct teql_master *master = netdev_priv(dev);
435 struct Qdisc_ops *ops = &master->qops;
436
437 master->dev = dev;
438 ops->priv_size = sizeof(struct teql_sched_data);
439
440 ops->enqueue = teql_enqueue;
441 ops->dequeue = teql_dequeue;
442 ops->peek = teql_peek;
443 ops->init = teql_qdisc_init;
444 ops->reset = teql_reset;
445 ops->destroy = teql_destroy;
446 ops->owner = THIS_MODULE;
447
448 dev->netdev_ops = &teql_netdev_ops;
449 dev->type = ARPHRD_VOID;
450 dev->mtu = 1500;
451 dev->tx_queue_len = 100;
452 dev->flags = IFF_NOARP;
453 dev->hard_header_len = LL_MAX_HEADER;
454 }
455
456 static LIST_HEAD(master_dev_list);
457 static int max_equalizers = 1;
458 module_param(max_equalizers, int, 0);
459 MODULE_PARM_DESC(max_equalizers, "Max number of link equalizers");
460
461 static int __init teql_init(void)
462 {
463 int i;
464 int err = -ENODEV;
465
466 for (i = 0; i < max_equalizers; i++) {
467 struct net_device *dev;
468 struct teql_master *master;
469
470 dev = alloc_netdev(sizeof(struct teql_master),
471 "teql%d", teql_master_setup);
472 if (!dev) {
473 err = -ENOMEM;
474 break;
475 }
476
477 if ((err = register_netdev(dev))) {
478 free_netdev(dev);
479 break;
480 }
481
482 master = netdev_priv(dev);
483
484 strlcpy(master->qops.id, dev->name, IFNAMSIZ);
485 err = register_qdisc(&master->qops);
486
487 if (err) {
488 unregister_netdev(dev);
489 free_netdev(dev);
490 break;
491 }
492
493 list_add_tail(&master->master_list, &master_dev_list);
494 }
495 return i ? 0 : err;
496 }
497
498 static void __exit teql_exit(void)
499 {
500 struct teql_master *master, *nxt;
501
502 list_for_each_entry_safe(master, nxt, &master_dev_list, master_list) {
503
504 list_del(&master->master_list);
505
506 unregister_qdisc(&master->qops);
507 unregister_netdev(master->dev);
508 free_netdev(master->dev);
509 }
510 }
511
512 module_init(teql_init);
513 module_exit(teql_exit);
514
515 MODULE_LICENSE("GPL");
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