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Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable
[deliverable/linux.git] / net / sched / sch_teql.c
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 if (!netif_tx_queue_stopped(slave_txq) &&
307 !netif_tx_queue_frozen(slave_txq) &&
308 slave_ops->ndo_start_xmit(skb, slave) == 0) {
309 __netif_tx_unlock(slave_txq);
310 master->slaves = NEXT_SLAVE(q);
311 netif_wake_queue(dev);
312 master->stats.tx_packets++;
313 master->stats.tx_bytes +=
314 qdisc_pkt_len(skb);
315 return 0;
316 }
317 __netif_tx_unlock(slave_txq);
318 }
319 if (netif_queue_stopped(dev))
320 busy = 1;
321 break;
322 case 1:
323 master->slaves = NEXT_SLAVE(q);
324 return 0;
325 default:
326 nores = 1;
327 break;
328 }
329 __skb_pull(skb, skb_network_offset(skb));
330 } while ((q = NEXT_SLAVE(q)) != start);
331
332 if (nores && skb_res == NULL) {
333 skb_res = skb;
334 goto restart;
335 }
336
337 if (busy) {
338 netif_stop_queue(dev);
339 return 1;
340 }
341 master->stats.tx_errors++;
342
343 drop:
344 master->stats.tx_dropped++;
345 dev_kfree_skb(skb);
346 return 0;
347 }
348
349 static int teql_master_open(struct net_device *dev)
350 {
351 struct Qdisc * q;
352 struct teql_master *m = netdev_priv(dev);
353 int mtu = 0xFFFE;
354 unsigned flags = IFF_NOARP|IFF_MULTICAST;
355
356 if (m->slaves == NULL)
357 return -EUNATCH;
358
359 flags = FMASK;
360
361 q = m->slaves;
362 do {
363 struct net_device *slave = qdisc_dev(q);
364
365 if (slave == NULL)
366 return -EUNATCH;
367
368 if (slave->mtu < mtu)
369 mtu = slave->mtu;
370 if (slave->hard_header_len > LL_MAX_HEADER)
371 return -EINVAL;
372
373 /* If all the slaves are BROADCAST, master is BROADCAST
374 If all the slaves are PtP, master is PtP
375 Otherwise, master is NBMA.
376 */
377 if (!(slave->flags&IFF_POINTOPOINT))
378 flags &= ~IFF_POINTOPOINT;
379 if (!(slave->flags&IFF_BROADCAST))
380 flags &= ~IFF_BROADCAST;
381 if (!(slave->flags&IFF_MULTICAST))
382 flags &= ~IFF_MULTICAST;
383 } while ((q = NEXT_SLAVE(q)) != m->slaves);
384
385 m->dev->mtu = mtu;
386 m->dev->flags = (m->dev->flags&~FMASK) | flags;
387 netif_start_queue(m->dev);
388 return 0;
389 }
390
391 static int teql_master_close(struct net_device *dev)
392 {
393 netif_stop_queue(dev);
394 return 0;
395 }
396
397 static struct net_device_stats *teql_master_stats(struct net_device *dev)
398 {
399 struct teql_master *m = netdev_priv(dev);
400 return &m->stats;
401 }
402
403 static int teql_master_mtu(struct net_device *dev, int new_mtu)
404 {
405 struct teql_master *m = netdev_priv(dev);
406 struct Qdisc *q;
407
408 if (new_mtu < 68)
409 return -EINVAL;
410
411 q = m->slaves;
412 if (q) {
413 do {
414 if (new_mtu > qdisc_dev(q)->mtu)
415 return -EINVAL;
416 } while ((q=NEXT_SLAVE(q)) != m->slaves);
417 }
418
419 dev->mtu = new_mtu;
420 return 0;
421 }
422
423 static const struct net_device_ops teql_netdev_ops = {
424 .ndo_open = teql_master_open,
425 .ndo_stop = teql_master_close,
426 .ndo_start_xmit = teql_master_xmit,
427 .ndo_get_stats = teql_master_stats,
428 .ndo_change_mtu = teql_master_mtu,
429 };
430
431 static __init void teql_master_setup(struct net_device *dev)
432 {
433 struct teql_master *master = netdev_priv(dev);
434 struct Qdisc_ops *ops = &master->qops;
435
436 master->dev = dev;
437 ops->priv_size = sizeof(struct teql_sched_data);
438
439 ops->enqueue = teql_enqueue;
440 ops->dequeue = teql_dequeue;
441 ops->peek = teql_peek;
442 ops->init = teql_qdisc_init;
443 ops->reset = teql_reset;
444 ops->destroy = teql_destroy;
445 ops->owner = THIS_MODULE;
446
447 dev->netdev_ops = &teql_netdev_ops;
448 dev->type = ARPHRD_VOID;
449 dev->mtu = 1500;
450 dev->tx_queue_len = 100;
451 dev->flags = IFF_NOARP;
452 dev->hard_header_len = LL_MAX_HEADER;
453 }
454
455 static LIST_HEAD(master_dev_list);
456 static int max_equalizers = 1;
457 module_param(max_equalizers, int, 0);
458 MODULE_PARM_DESC(max_equalizers, "Max number of link equalizers");
459
460 static int __init teql_init(void)
461 {
462 int i;
463 int err = -ENODEV;
464
465 for (i = 0; i < max_equalizers; i++) {
466 struct net_device *dev;
467 struct teql_master *master;
468
469 dev = alloc_netdev(sizeof(struct teql_master),
470 "teql%d", teql_master_setup);
471 if (!dev) {
472 err = -ENOMEM;
473 break;
474 }
475
476 if ((err = register_netdev(dev))) {
477 free_netdev(dev);
478 break;
479 }
480
481 master = netdev_priv(dev);
482
483 strlcpy(master->qops.id, dev->name, IFNAMSIZ);
484 err = register_qdisc(&master->qops);
485
486 if (err) {
487 unregister_netdev(dev);
488 free_netdev(dev);
489 break;
490 }
491
492 list_add_tail(&master->master_list, &master_dev_list);
493 }
494 return i ? 0 : err;
495 }
496
497 static void __exit teql_exit(void)
498 {
499 struct teql_master *master, *nxt;
500
501 list_for_each_entry_safe(master, nxt, &master_dev_list, master_list) {
502
503 list_del(&master->master_list);
504
505 unregister_qdisc(&master->qops);
506 unregister_netdev(master->dev);
507 free_netdev(master->dev);
508 }
509 }
510
511 module_init(teql_init);
512 module_exit(teql_exit);
513
514 MODULE_LICENSE("GPL");
Linux kernel - Deliverables
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