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powerpc/pseries: Cleanup comments in EEH aux components
[linux-2.6.git] / net / sched / sch_teql.c
blob45326599fda37786e7ac2104e77bbd1bfa2b5083
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/slab.h>
15 #include <linux/string.h>
16 #include <linux/errno.h>
17 #include <linux/if_arp.h>
18 #include <linux/netdevice.h>
19 #include <linux/init.h>
20 #include <linux/skbuff.h>
21 #include <linux/moduleparam.h>
22 #include <net/dst.h>
23 #include <net/neighbour.h>
24 #include <net/pkt_sched.h>
25
26 /*
27 How to setup it.
28 ----------------
29
30 After loading this module you will find a new device teqlN
31 and new qdisc with the same name. To join a slave to the equalizer
32 you should just set this qdisc on a device f.e.
33
34 # tc qdisc add dev eth0 root teql0
35 # tc qdisc add dev eth1 root teql0
36
37 That's all. Full PnP 8)
38
39 Applicability.
40 --------------
41
42 1. Slave devices MUST be active devices, i.e., they must raise the tbusy
43 signal and generate EOI events. If you want to equalize virtual devices
44 like tunnels, use a normal eql device.
45 2. This device puts no limitations on physical slave characteristics
46 f.e. it will equalize 9600baud line and 100Mb ethernet perfectly :-)
47 Certainly, large difference in link speeds will make the resulting
48 eqalized link unusable, because of huge packet reordering.
49 I estimate an upper useful difference as ~10 times.
50 3. If the slave requires address resolution, only protocols using
51 neighbour cache (IPv4/IPv6) will work over the equalized link.
52 Other protocols are still allowed to use the slave device directly,
53 which will not break load balancing, though native slave
54 traffic will have the highest priority. */
55
56 struct teql_master {
57 struct Qdisc_ops qops;
58 struct net_device *dev;
59 struct Qdisc *slaves;
60 struct list_head master_list;
61 unsigned long tx_bytes;
62 unsigned long tx_packets;
63 unsigned long tx_errors;
64 unsigned long tx_dropped;
65 };
66
67 struct teql_sched_data {
68 struct Qdisc *next;
69 struct teql_master *m;
70 struct neighbour *ncache;
71 struct sk_buff_head q;
72 };
73
74 #define NEXT_SLAVE(q) (((struct teql_sched_data *)qdisc_priv(q))->next)
75
76 #define FMASK (IFF_BROADCAST | IFF_POINTOPOINT)
77
78 /* "teql*" qdisc routines */
79
80 static int
81 teql_enqueue(struct sk_buff *skb, struct Qdisc *sch)
82 {
83 struct net_device *dev = qdisc_dev(sch);
84 struct teql_sched_data *q = qdisc_priv(sch);
85
86 if (q->q.qlen < dev->tx_queue_len) {
87 __skb_queue_tail(&q->q, skb);
88 return NET_XMIT_SUCCESS;
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 } else {
112 qdisc_bstats_update(sch, skb);
113 }
114 sch->q.qlen = dat->q.qlen + dat_queue->qdisc->q.qlen;
115 return skb;
116 }
117
118 static struct sk_buff *
119 teql_peek(struct Qdisc *sch)
120 {
121 /* teql is meant to be used as root qdisc */
122 return NULL;
123 }
124
125 static inline void
126 teql_neigh_release(struct neighbour *n)
127 {
128 if (n)
129 neigh_release(n);
130 }
131
132 static void
133 teql_reset(struct Qdisc *sch)
134 {
135 struct teql_sched_data *dat = qdisc_priv(sch);
136
137 skb_queue_purge(&dat->q);
138 sch->q.qlen = 0;
139 teql_neigh_release(xchg(&dat->ncache, NULL));
140 }
141
142 static void
143 teql_destroy(struct Qdisc *sch)
144 {
145 struct Qdisc *q, *prev;
146 struct teql_sched_data *dat = qdisc_priv(sch);
147 struct teql_master *master = dat->m;
148
149 prev = master->slaves;
150 if (prev) {
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 &&
198 !(dev->flags & IFF_POINTOPOINT)) ||
199 (m->dev->flags & IFF_BROADCAST &&
200 !(dev->flags & IFF_BROADCAST)) ||
201 (m->dev->flags & IFF_MULTICAST &&
202 !(dev->flags & IFF_MULTICAST)) ||
203 dev->mtu < m->dev->mtu)
204 return -EINVAL;
205 } else {
206 if (!(dev->flags&IFF_POINTOPOINT))
207 m->dev->flags &= ~IFF_POINTOPOINT;
208 if (!(dev->flags&IFF_BROADCAST))
209 m->dev->flags &= ~IFF_BROADCAST;
210 if (!(dev->flags&IFF_MULTICAST))
211 m->dev->flags &= ~IFF_MULTICAST;
212 if (dev->mtu < m->dev->mtu)
213 m->dev->mtu = dev->mtu;
214 }
215 q->next = NEXT_SLAVE(m->slaves);
216 NEXT_SLAVE(m->slaves) = sch;
217 } else {
218 q->next = sch;
219 m->slaves = sch;
220 m->dev->mtu = dev->mtu;
221 m->dev->flags = (m->dev->flags&~FMASK)|(dev->flags&FMASK);
222 }
223 return 0;
224 }
225
226
227 static int
228 __teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res,
229 struct net_device *dev, struct netdev_queue *txq,
230 struct neighbour *mn)
231 {
232 struct teql_sched_data *q = qdisc_priv(txq->qdisc);
233 struct neighbour *n = q->ncache;
234
235 if (mn->tbl == NULL)
236 return -EINVAL;
237 if (n && n->tbl == mn->tbl &&
238 memcmp(n->primary_key, mn->primary_key, mn->tbl->key_len) == 0) {
239 atomic_inc(&n->refcnt);
240 } else {
241 n = __neigh_lookup_errno(mn->tbl, mn->primary_key, dev);
242 if (IS_ERR(n))
243 return PTR_ERR(n);
244 }
245 if (neigh_event_send(n, skb_res) == 0) {
246 int err;
247 char haddr[MAX_ADDR_LEN];
248
249 neigh_ha_snapshot(haddr, n, dev);
250 err = dev_hard_header(skb, dev, ntohs(skb->protocol), haddr,
251 NULL, skb->len);
252
253 if (err < 0) {
254 neigh_release(n);
255 return -EINVAL;
256 }
257 teql_neigh_release(xchg(&q->ncache, n));
258 return 0;
259 }
260 neigh_release(n);
261 return (skb_res == NULL) ? -EAGAIN : 1;
262 }
263
264 static inline int teql_resolve(struct sk_buff *skb,
265 struct sk_buff *skb_res,
266 struct net_device *dev,
267 struct netdev_queue *txq)
268 {
269 struct dst_entry *dst = skb_dst(skb);
270 struct neighbour *mn;
271 int res;
272
273 if (txq->qdisc == &noop_qdisc)
274 return -ENODEV;
275
276 if (!dev->header_ops || !dst)
277 return 0;
278
279 rcu_read_lock();
280 mn = dst_get_neighbour_noref(dst);
281 res = mn ? __teql_resolve(skb, skb_res, dev, txq, mn) : 0;
282 rcu_read_unlock();
283
284 return res;
285 }
286
287 static netdev_tx_t teql_master_xmit(struct sk_buff *skb, struct net_device *dev)
288 {
289 struct teql_master *master = netdev_priv(dev);
290 struct Qdisc *start, *q;
291 int busy;
292 int nores;
293 int subq = skb_get_queue_mapping(skb);
294 struct sk_buff *skb_res = NULL;
295
296 start = master->slaves;
297
298 restart:
299 nores = 0;
300 busy = 0;
301
302 q = start;
303 if (!q)
304 goto drop;
305
306 do {
307 struct net_device *slave = qdisc_dev(q);
308 struct netdev_queue *slave_txq = netdev_get_tx_queue(slave, 0);
309 const struct net_device_ops *slave_ops = slave->netdev_ops;
310
311 if (slave_txq->qdisc_sleeping != q)
312 continue;
313 if (netif_xmit_stopped(netdev_get_tx_queue(slave, subq)) ||
314 !netif_running(slave)) {
315 busy = 1;
316 continue;
317 }
318
319 switch (teql_resolve(skb, skb_res, slave, slave_txq)) {
320 case 0:
321 if (__netif_tx_trylock(slave_txq)) {
322 unsigned int length = qdisc_pkt_len(skb);
323
324 if (!netif_xmit_frozen_or_stopped(slave_txq) &&
325 slave_ops->ndo_start_xmit(skb, slave) == NETDEV_TX_OK) {
326 txq_trans_update(slave_txq);
327 __netif_tx_unlock(slave_txq);
328 master->slaves = NEXT_SLAVE(q);
329 netif_wake_queue(dev);
330 master->tx_packets++;
331 master->tx_bytes += length;
332 return NETDEV_TX_OK;
333 }
334 __netif_tx_unlock(slave_txq);
335 }
336 if (netif_xmit_stopped(netdev_get_tx_queue(dev, 0)))
337 busy = 1;
338 break;
339 case 1:
340 master->slaves = NEXT_SLAVE(q);
341 return NETDEV_TX_OK;
342 default:
343 nores = 1;
344 break;
345 }
346 __skb_pull(skb, skb_network_offset(skb));
347 } while ((q = NEXT_SLAVE(q)) != start);
348
349 if (nores && skb_res == NULL) {
350 skb_res = skb;
351 goto restart;
352 }
353
354 if (busy) {
355 netif_stop_queue(dev);
356 return NETDEV_TX_BUSY;
357 }
358 master->tx_errors++;
359
360 drop:
361 master->tx_dropped++;
362 dev_kfree_skb(skb);
363 return NETDEV_TX_OK;
364 }
365
366 static int teql_master_open(struct net_device *dev)
367 {
368 struct Qdisc *q;
369 struct teql_master *m = netdev_priv(dev);
370 int mtu = 0xFFFE;
371 unsigned int flags = IFF_NOARP | IFF_MULTICAST;
372
373 if (m->slaves == NULL)
374 return -EUNATCH;
375
376 flags = FMASK;
377
378 q = m->slaves;
379 do {
380 struct net_device *slave = qdisc_dev(q);
381
382 if (slave == NULL)
383 return -EUNATCH;
384
385 if (slave->mtu < mtu)
386 mtu = slave->mtu;
387 if (slave->hard_header_len > LL_MAX_HEADER)
388 return -EINVAL;
389
390 /* If all the slaves are BROADCAST, master is BROADCAST
391 If all the slaves are PtP, master is PtP
392 Otherwise, master is NBMA.
393 */
394 if (!(slave->flags&IFF_POINTOPOINT))
395 flags &= ~IFF_POINTOPOINT;
396 if (!(slave->flags&IFF_BROADCAST))
397 flags &= ~IFF_BROADCAST;
398 if (!(slave->flags&IFF_MULTICAST))
399 flags &= ~IFF_MULTICAST;
400 } while ((q = NEXT_SLAVE(q)) != m->slaves);
401
402 m->dev->mtu = mtu;
403 m->dev->flags = (m->dev->flags&~FMASK) | flags;
404 netif_start_queue(m->dev);
405 return 0;
406 }
407
408 static int teql_master_close(struct net_device *dev)
409 {
410 netif_stop_queue(dev);
411 return 0;
412 }
413
414 static struct rtnl_link_stats64 *teql_master_stats64(struct net_device *dev,
415 struct rtnl_link_stats64 *stats)
416 {
417 struct teql_master *m = netdev_priv(dev);
418
419 stats->tx_packets = m->tx_packets;
420 stats->tx_bytes = m->tx_bytes;
421 stats->tx_errors = m->tx_errors;
422 stats->tx_dropped = m->tx_dropped;
423 return stats;
424 }
425
426 static int teql_master_mtu(struct net_device *dev, int new_mtu)
427 {
428 struct teql_master *m = netdev_priv(dev);
429 struct Qdisc *q;
430
431 if (new_mtu < 68)
432 return -EINVAL;
433
434 q = m->slaves;
435 if (q) {
436 do {
437 if (new_mtu > qdisc_dev(q)->mtu)
438 return -EINVAL;
439 } while ((q = NEXT_SLAVE(q)) != m->slaves);
440 }
441
442 dev->mtu = new_mtu;
443 return 0;
444 }
445
446 static const struct net_device_ops teql_netdev_ops = {
447 .ndo_open = teql_master_open,
448 .ndo_stop = teql_master_close,
449 .ndo_start_xmit = teql_master_xmit,
450 .ndo_get_stats64 = teql_master_stats64,
451 .ndo_change_mtu = teql_master_mtu,
452 };
453
454 static __init void teql_master_setup(struct net_device *dev)
455 {
456 struct teql_master *master = netdev_priv(dev);
457 struct Qdisc_ops *ops = &master->qops;
458
459 master->dev = dev;
460 ops->priv_size = sizeof(struct teql_sched_data);
461
462 ops->enqueue = teql_enqueue;
463 ops->dequeue = teql_dequeue;
464 ops->peek = teql_peek;
465 ops->init = teql_qdisc_init;
466 ops->reset = teql_reset;
467 ops->destroy = teql_destroy;
468 ops->owner = THIS_MODULE;
469
470 dev->netdev_ops = &teql_netdev_ops;
471 dev->type = ARPHRD_VOID;
472 dev->mtu = 1500;
473 dev->tx_queue_len = 100;
474 dev->flags = IFF_NOARP;
475 dev->hard_header_len = LL_MAX_HEADER;
476 dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
477 }
478
479 static LIST_HEAD(master_dev_list);
480 static int max_equalizers = 1;
481 module_param(max_equalizers, int, 0);
482 MODULE_PARM_DESC(max_equalizers, "Max number of link equalizers");
483
484 static int __init teql_init(void)
485 {
486 int i;
487 int err = -ENODEV;
488
489 for (i = 0; i < max_equalizers; i++) {
490 struct net_device *dev;
491 struct teql_master *master;
492
493 dev = alloc_netdev(sizeof(struct teql_master),
494 "teql%d", teql_master_setup);
495 if (!dev) {
496 err = -ENOMEM;
497 break;
498 }
499
500 if ((err = register_netdev(dev))) {
501 free_netdev(dev);
502 break;
503 }
504
505 master = netdev_priv(dev);
506
507 strlcpy(master->qops.id, dev->name, IFNAMSIZ);
508 err = register_qdisc(&master->qops);
509
510 if (err) {
511 unregister_netdev(dev);
512 free_netdev(dev);
513 break;
514 }
515
516 list_add_tail(&master->master_list, &master_dev_list);
517 }
518 return i ? 0 : err;
519 }
520
521 static void __exit teql_exit(void)
522 {
523 struct teql_master *master, *nxt;
524
525 list_for_each_entry_safe(master, nxt, &master_dev_list, master_list) {
526
527 list_del(&master->master_list);
528
529 unregister_qdisc(&master->qops);
530 unregister_netdev(master->dev);
531 free_netdev(master->dev);
532 }
533 }
534
535 module_init(teql_init);
536 module_exit(teql_exit);
537
538 MODULE_LICENSE("GPL");
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