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xilinx_hwicap: remove improper wording in license statement
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / net / sched / sch_teql.c
blobd35ef059abb1781e41becb98e6b1a15e3596001b
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 int
97 teql_requeue(struct sk_buff *skb, struct Qdisc* sch)
98 {
99 struct teql_sched_data *q = qdisc_priv(sch);
100
101 __skb_queue_head(&q->q, skb);
102 sch->qstats.requeues++;
103 return 0;
104 }
105
106 static struct sk_buff *
107 teql_dequeue(struct Qdisc* sch)
108 {
109 struct teql_sched_data *dat = qdisc_priv(sch);
110 struct netdev_queue *dat_queue;
111 struct sk_buff *skb;
112
113 skb = __skb_dequeue(&dat->q);
114 dat_queue = netdev_get_tx_queue(dat->m->dev, 0);
115 if (skb == NULL) {
116 struct net_device *m = qdisc_dev(dat_queue->qdisc);
117 if (m) {
118 dat->m->slaves = sch;
119 netif_wake_queue(m);
120 }
121 }
122 sch->q.qlen = dat->q.qlen + dat_queue->qdisc->q.qlen;
123 return skb;
124 }
125
126 static __inline__ void
127 teql_neigh_release(struct neighbour *n)
128 {
129 if (n)
130 neigh_release(n);
131 }
132
133 static void
134 teql_reset(struct Qdisc* sch)
135 {
136 struct teql_sched_data *dat = qdisc_priv(sch);
137
138 skb_queue_purge(&dat->q);
139 sch->q.qlen = 0;
140 teql_neigh_release(xchg(&dat->ncache, NULL));
141 }
142
143 static void
144 teql_destroy(struct Qdisc* sch)
145 {
146 struct Qdisc *q, *prev;
147 struct teql_sched_data *dat = qdisc_priv(sch);
148 struct teql_master *master = dat->m;
149
150 if ((prev = master->slaves) != NULL) {
151 do {
152 q = NEXT_SLAVE(prev);
153 if (q == sch) {
154 NEXT_SLAVE(prev) = NEXT_SLAVE(q);
155 if (q == master->slaves) {
156 master->slaves = NEXT_SLAVE(q);
157 if (q == master->slaves) {
158 struct netdev_queue *txq;
159 spinlock_t *root_lock;
160
161 txq = netdev_get_tx_queue(master->dev, 0);
162 master->slaves = NULL;
163
164 root_lock = qdisc_root_sleeping_lock(txq->qdisc);
165 spin_lock_bh(root_lock);
166 qdisc_reset(txq->qdisc);
167 spin_unlock_bh(root_lock);
168 }
169 }
170 skb_queue_purge(&dat->q);
171 teql_neigh_release(xchg(&dat->ncache, NULL));
172 break;
173 }
174
175 } while ((prev = q) != master->slaves);
176 }
177 }
178
179 static int teql_qdisc_init(struct Qdisc *sch, struct nlattr *opt)
180 {
181 struct net_device *dev = qdisc_dev(sch);
182 struct teql_master *m = (struct teql_master*)sch->ops;
183 struct teql_sched_data *q = qdisc_priv(sch);
184
185 if (dev->hard_header_len > m->dev->hard_header_len)
186 return -EINVAL;
187
188 if (m->dev == dev)
189 return -ELOOP;
190
191 q->m = m;
192
193 skb_queue_head_init(&q->q);
194
195 if (m->slaves) {
196 if (m->dev->flags & IFF_UP) {
197 if ((m->dev->flags&IFF_POINTOPOINT && !(dev->flags&IFF_POINTOPOINT))
198 || (m->dev->flags&IFF_BROADCAST && !(dev->flags&IFF_BROADCAST))
199 || (m->dev->flags&IFF_MULTICAST && !(dev->flags&IFF_MULTICAST))
200 || dev->mtu < m->dev->mtu)
201 return -EINVAL;
202 } else {
203 if (!(dev->flags&IFF_POINTOPOINT))
204 m->dev->flags &= ~IFF_POINTOPOINT;
205 if (!(dev->flags&IFF_BROADCAST))
206 m->dev->flags &= ~IFF_BROADCAST;
207 if (!(dev->flags&IFF_MULTICAST))
208 m->dev->flags &= ~IFF_MULTICAST;
209 if (dev->mtu < m->dev->mtu)
210 m->dev->mtu = dev->mtu;
211 }
212 q->next = NEXT_SLAVE(m->slaves);
213 NEXT_SLAVE(m->slaves) = sch;
214 } else {
215 q->next = sch;
216 m->slaves = sch;
217 m->dev->mtu = dev->mtu;
218 m->dev->flags = (m->dev->flags&~FMASK)|(dev->flags&FMASK);
219 }
220 return 0;
221 }
222
223
224 static int
225 __teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res, struct net_device *dev)
226 {
227 struct netdev_queue *dev_queue = netdev_get_tx_queue(dev, 0);
228 struct teql_sched_data *q = qdisc_priv(dev_queue->qdisc);
229 struct neighbour *mn = skb->dst->neighbour;
230 struct neighbour *n = q->ncache;
231
232 if (mn->tbl == NULL)
233 return -EINVAL;
234 if (n && n->tbl == mn->tbl &&
235 memcmp(n->primary_key, mn->primary_key, mn->tbl->key_len) == 0) {
236 atomic_inc(&n->refcnt);
237 } else {
238 n = __neigh_lookup_errno(mn->tbl, mn->primary_key, dev);
239 if (IS_ERR(n))
240 return PTR_ERR(n);
241 }
242 if (neigh_event_send(n, skb_res) == 0) {
243 int err;
244
245 read_lock(&n->lock);
246 err = dev_hard_header(skb, dev, ntohs(skb->protocol),
247 n->ha, NULL, skb->len);
248 read_unlock(&n->lock);
249
250 if (err < 0) {
251 neigh_release(n);
252 return -EINVAL;
253 }
254 teql_neigh_release(xchg(&q->ncache, n));
255 return 0;
256 }
257 neigh_release(n);
258 return (skb_res == NULL) ? -EAGAIN : 1;
259 }
260
261 static inline int teql_resolve(struct sk_buff *skb,
262 struct sk_buff *skb_res, struct net_device *dev)
263 {
264 struct netdev_queue *txq = netdev_get_tx_queue(dev, 0);
265 if (txq->qdisc == &noop_qdisc)
266 return -ENODEV;
267
268 if (dev->header_ops == 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 subq = skb_get_queue_mapping(skb);
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 = qdisc_dev(q);
295 struct netdev_queue *slave_txq;
296
297 slave_txq = netdev_get_tx_queue(slave, 0);
298 if (slave_txq->qdisc_sleeping != q)
299 continue;
300 if (__netif_subqueue_stopped(slave, subq) ||
301 !netif_running(slave)) {
302 busy = 1;
303 continue;
304 }
305
306 switch (teql_resolve(skb, skb_res, slave)) {
307 case 0:
308 if (__netif_tx_trylock(slave_txq)) {
309 if (!netif_tx_queue_stopped(slave_txq) &&
310 !netif_tx_queue_frozen(slave_txq) &&
311 slave->hard_start_xmit(skb, slave) == 0) {
312 __netif_tx_unlock(slave_txq);
313 master->slaves = NEXT_SLAVE(q);
314 netif_wake_queue(dev);
315 master->stats.tx_packets++;
316 master->stats.tx_bytes +=
317 qdisc_pkt_len(skb);
318 return 0;
319 }
320 __netif_tx_unlock(slave_txq);
321 }
322 if (netif_queue_stopped(dev))
323 busy = 1;
324 break;
325 case 1:
326 master->slaves = NEXT_SLAVE(q);
327 return 0;
328 default:
329 nores = 1;
330 break;
331 }
332 __skb_pull(skb, skb_network_offset(skb));
333 } while ((q = NEXT_SLAVE(q)) != start);
334
335 if (nores && skb_res == NULL) {
336 skb_res = skb;
337 goto restart;
338 }
339
340 if (busy) {
341 netif_stop_queue(dev);
342 return 1;
343 }
344 master->stats.tx_errors++;
345
346 drop:
347 master->stats.tx_dropped++;
348 dev_kfree_skb(skb);
349 return 0;
350 }
351
352 static int teql_master_open(struct net_device *dev)
353 {
354 struct Qdisc * q;
355 struct teql_master *m = netdev_priv(dev);
356 int mtu = 0xFFFE;
357 unsigned flags = IFF_NOARP|IFF_MULTICAST;
358
359 if (m->slaves == NULL)
360 return -EUNATCH;
361
362 flags = FMASK;
363
364 q = m->slaves;
365 do {
366 struct net_device *slave = qdisc_dev(q);
367
368 if (slave == NULL)
369 return -EUNATCH;
370
371 if (slave->mtu < mtu)
372 mtu = slave->mtu;
373 if (slave->hard_header_len > LL_MAX_HEADER)
374 return -EINVAL;
375
376 /* If all the slaves are BROADCAST, master is BROADCAST
377 If all the slaves are PtP, master is PtP
378 Otherwise, master is NBMA.
379 */
380 if (!(slave->flags&IFF_POINTOPOINT))
381 flags &= ~IFF_POINTOPOINT;
382 if (!(slave->flags&IFF_BROADCAST))
383 flags &= ~IFF_BROADCAST;
384 if (!(slave->flags&IFF_MULTICAST))
385 flags &= ~IFF_MULTICAST;
386 } while ((q = NEXT_SLAVE(q)) != m->slaves);
387
388 m->dev->mtu = mtu;
389 m->dev->flags = (m->dev->flags&~FMASK) | flags;
390 netif_start_queue(m->dev);
391 return 0;
392 }
393
394 static int teql_master_close(struct net_device *dev)
395 {
396 netif_stop_queue(dev);
397 return 0;
398 }
399
400 static struct net_device_stats *teql_master_stats(struct net_device *dev)
401 {
402 struct teql_master *m = netdev_priv(dev);
403 return &m->stats;
404 }
405
406 static int teql_master_mtu(struct net_device *dev, int new_mtu)
407 {
408 struct teql_master *m = netdev_priv(dev);
409 struct Qdisc *q;
410
411 if (new_mtu < 68)
412 return -EINVAL;
413
414 q = m->slaves;
415 if (q) {
416 do {
417 if (new_mtu > qdisc_dev(q)->mtu)
418 return -EINVAL;
419 } while ((q=NEXT_SLAVE(q)) != m->slaves);
420 }
421
422 dev->mtu = new_mtu;
423 return 0;
424 }
425
426 static __init void teql_master_setup(struct net_device *dev)
427 {
428 struct teql_master *master = netdev_priv(dev);
429 struct Qdisc_ops *ops = &master->qops;
430
431 master->dev = dev;
432 ops->priv_size = sizeof(struct teql_sched_data);
433
434 ops->enqueue = teql_enqueue;
435 ops->dequeue = teql_dequeue;
436 ops->requeue = teql_requeue;
437 ops->init = teql_qdisc_init;
438 ops->reset = teql_reset;
439 ops->destroy = teql_destroy;
440 ops->owner = THIS_MODULE;
441
442 dev->open = teql_master_open;
443 dev->hard_start_xmit = teql_master_xmit;
444 dev->stop = teql_master_close;
445 dev->get_stats = teql_master_stats;
446 dev->change_mtu = teql_master_mtu;
447 dev->type = ARPHRD_VOID;
448 dev->mtu = 1500;
449 dev->tx_queue_len = 100;
450 dev->flags = IFF_NOARP;
451 dev->hard_header_len = LL_MAX_HEADER;
452 }
453
454 static LIST_HEAD(master_dev_list);
455 static int max_equalizers = 1;
456 module_param(max_equalizers, int, 0);
457 MODULE_PARM_DESC(max_equalizers, "Max number of link equalizers");
458
459 static int __init teql_init(void)
460 {
461 int i;
462 int err = -ENODEV;
463
464 for (i = 0; i < max_equalizers; i++) {
465 struct net_device *dev;
466 struct teql_master *master;
467
468 dev = alloc_netdev(sizeof(struct teql_master),
469 "teql%d", teql_master_setup);
470 if (!dev) {
471 err = -ENOMEM;
472 break;
473 }
474
475 if ((err = register_netdev(dev))) {
476 free_netdev(dev);
477 break;
478 }
479
480 master = netdev_priv(dev);
481
482 strlcpy(master->qops.id, dev->name, IFNAMSIZ);
483 err = register_qdisc(&master->qops);
484
485 if (err) {
486 unregister_netdev(dev);
487 free_netdev(dev);
488 break;
489 }
490
491 list_add_tail(&master->master_list, &master_dev_list);
492 }
493 return i ? 0 : err;
494 }
495
496 static void __exit teql_exit(void)
497 {
498 struct teql_master *master, *nxt;
499
500 list_for_each_entry_safe(master, nxt, &master_dev_list, master_list) {
501
502 list_del(&master->master_list);
503
504 unregister_qdisc(&master->qops);
505 unregister_netdev(master->dev);
506 free_netdev(master->dev);
507 }
508 }
509
510 module_init(teql_init);
511 module_exit(teql_exit);
512
513 MODULE_LICENSE("GPL");
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