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Merge branch 'upstream-linus' of master.kernel.org:/pub/scm/linux/kernel/git/jgarzik...
[linux-2.6/libata-dev.git] / net / sched / sch_teql.c
blob0968184ea6becc6f58ba848fc76c629aa8e26126
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|IFF_BROADCAST)
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 = sch->dev;
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 += skb->len;
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 sk_buff *skb;
111
112 skb = __skb_dequeue(&dat->q);
113 if (skb == NULL) {
114 struct net_device *m = dat->m->dev->qdisc->dev;
115 if (m) {
116 dat->m->slaves = sch;
117 netif_wake_queue(m);
118 }
119 }
120 sch->q.qlen = dat->q.qlen + dat->m->dev->qdisc->q.qlen;
121 return skb;
122 }
123
124 static __inline__ void
125 teql_neigh_release(struct neighbour *n)
126 {
127 if (n)
128 neigh_release(n);
129 }
130
131 static void
132 teql_reset(struct Qdisc* sch)
133 {
134 struct teql_sched_data *dat = qdisc_priv(sch);
135
136 skb_queue_purge(&dat->q);
137 sch->q.qlen = 0;
138 teql_neigh_release(xchg(&dat->ncache, NULL));
139 }
140
141 static void
142 teql_destroy(struct Qdisc* sch)
143 {
144 struct Qdisc *q, *prev;
145 struct teql_sched_data *dat = qdisc_priv(sch);
146 struct teql_master *master = dat->m;
147
148 if ((prev = master->slaves) != NULL) {
149 do {
150 q = NEXT_SLAVE(prev);
151 if (q == sch) {
152 NEXT_SLAVE(prev) = NEXT_SLAVE(q);
153 if (q == master->slaves) {
154 master->slaves = NEXT_SLAVE(q);
155 if (q == master->slaves) {
156 master->slaves = NULL;
157 spin_lock_bh(&master->dev->queue_lock);
158 qdisc_reset(master->dev->qdisc);
159 spin_unlock_bh(&master->dev->queue_lock);
160 }
161 }
162 skb_queue_purge(&dat->q);
163 teql_neigh_release(xchg(&dat->ncache, NULL));
164 break;
165 }
166
167 } while ((prev = q) != master->slaves);
168 }
169 }
170
171 static int teql_qdisc_init(struct Qdisc *sch, struct rtattr *opt)
172 {
173 struct net_device *dev = sch->dev;
174 struct teql_master *m = (struct teql_master*)sch->ops;
175 struct teql_sched_data *q = qdisc_priv(sch);
176
177 if (dev->hard_header_len > m->dev->hard_header_len)
178 return -EINVAL;
179
180 if (m->dev == dev)
181 return -ELOOP;
182
183 q->m = m;
184
185 skb_queue_head_init(&q->q);
186
187 if (m->slaves) {
188 if (m->dev->flags & IFF_UP) {
189 if ((m->dev->flags&IFF_POINTOPOINT && !(dev->flags&IFF_POINTOPOINT))
190 || (m->dev->flags&IFF_BROADCAST && !(dev->flags&IFF_BROADCAST))
191 || (m->dev->flags&IFF_MULTICAST && !(dev->flags&IFF_MULTICAST))
192 || dev->mtu < m->dev->mtu)
193 return -EINVAL;
194 } else {
195 if (!(dev->flags&IFF_POINTOPOINT))
196 m->dev->flags &= ~IFF_POINTOPOINT;
197 if (!(dev->flags&IFF_BROADCAST))
198 m->dev->flags &= ~IFF_BROADCAST;
199 if (!(dev->flags&IFF_MULTICAST))
200 m->dev->flags &= ~IFF_MULTICAST;
201 if (dev->mtu < m->dev->mtu)
202 m->dev->mtu = dev->mtu;
203 }
204 q->next = NEXT_SLAVE(m->slaves);
205 NEXT_SLAVE(m->slaves) = sch;
206 } else {
207 q->next = sch;
208 m->slaves = sch;
209 m->dev->mtu = dev->mtu;
210 m->dev->flags = (m->dev->flags&~FMASK)|(dev->flags&FMASK);
211 }
212 return 0;
213 }
214
215
216 static int
217 __teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res, struct net_device *dev)
218 {
219 struct teql_sched_data *q = qdisc_priv(dev->qdisc);
220 struct neighbour *mn = skb->dst->neighbour;
221 struct neighbour *n = q->ncache;
222
223 if (mn->tbl == NULL)
224 return -EINVAL;
225 if (n && n->tbl == mn->tbl &&
226 memcmp(n->primary_key, mn->primary_key, mn->tbl->key_len) == 0) {
227 atomic_inc(&n->refcnt);
228 } else {
229 n = __neigh_lookup_errno(mn->tbl, mn->primary_key, dev);
230 if (IS_ERR(n))
231 return PTR_ERR(n);
232 }
233 if (neigh_event_send(n, skb_res) == 0) {
234 int err;
235 read_lock(&n->lock);
236 err = dev->hard_header(skb, dev, ntohs(skb->protocol), n->ha, NULL, skb->len);
237 read_unlock(&n->lock);
238 if (err < 0) {
239 neigh_release(n);
240 return -EINVAL;
241 }
242 teql_neigh_release(xchg(&q->ncache, n));
243 return 0;
244 }
245 neigh_release(n);
246 return (skb_res == NULL) ? -EAGAIN : 1;
247 }
248
249 static __inline__ int
250 teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res, struct net_device *dev)
251 {
252 if (dev->hard_header == NULL ||
253 skb->dst == NULL ||
254 skb->dst->neighbour == NULL)
255 return 0;
256 return __teql_resolve(skb, skb_res, dev);
257 }
258
259 static int teql_master_xmit(struct sk_buff *skb, struct net_device *dev)
260 {
261 struct teql_master *master = netdev_priv(dev);
262 struct Qdisc *start, *q;
263 int busy;
264 int nores;
265 int len = skb->len;
266 int subq = skb->queue_mapping;
267 struct sk_buff *skb_res = NULL;
268
269 start = master->slaves;
270
271 restart:
272 nores = 0;
273 busy = 0;
274
275 if ((q = start) == NULL)
276 goto drop;
277
278 do {
279 struct net_device *slave = q->dev;
280
281 if (slave->qdisc_sleeping != q)
282 continue;
283 if (netif_queue_stopped(slave) ||
284 netif_subqueue_stopped(slave, subq) ||
285 !netif_running(slave)) {
286 busy = 1;
287 continue;
288 }
289
290 switch (teql_resolve(skb, skb_res, slave)) {
291 case 0:
292 if (netif_tx_trylock(slave)) {
293 if (!netif_queue_stopped(slave) &&
294 !netif_subqueue_stopped(slave, subq) &&
295 slave->hard_start_xmit(skb, slave) == 0) {
296 netif_tx_unlock(slave);
297 master->slaves = NEXT_SLAVE(q);
298 netif_wake_queue(dev);
299 master->stats.tx_packets++;
300 master->stats.tx_bytes += len;
301 return 0;
302 }
303 netif_tx_unlock(slave);
304 }
305 if (netif_queue_stopped(dev))
306 busy = 1;
307 break;
308 case 1:
309 master->slaves = NEXT_SLAVE(q);
310 return 0;
311 default:
312 nores = 1;
313 break;
314 }
315 __skb_pull(skb, skb_network_offset(skb));
316 } while ((q = NEXT_SLAVE(q)) != start);
317
318 if (nores && skb_res == NULL) {
319 skb_res = skb;
320 goto restart;
321 }
322
323 if (busy) {
324 netif_stop_queue(dev);
325 return 1;
326 }
327 master->stats.tx_errors++;
328
329 drop:
330 master->stats.tx_dropped++;
331 dev_kfree_skb(skb);
332 return 0;
333 }
334
335 static int teql_master_open(struct net_device *dev)
336 {
337 struct Qdisc * q;
338 struct teql_master *m = netdev_priv(dev);
339 int mtu = 0xFFFE;
340 unsigned flags = IFF_NOARP|IFF_MULTICAST;
341
342 if (m->slaves == NULL)
343 return -EUNATCH;
344
345 flags = FMASK;
346
347 q = m->slaves;
348 do {
349 struct net_device *slave = q->dev;
350
351 if (slave == NULL)
352 return -EUNATCH;
353
354 if (slave->mtu < mtu)
355 mtu = slave->mtu;
356 if (slave->hard_header_len > LL_MAX_HEADER)
357 return -EINVAL;
358
359 /* If all the slaves are BROADCAST, master is BROADCAST
360 If all the slaves are PtP, master is PtP
361 Otherwise, master is NBMA.
362 */
363 if (!(slave->flags&IFF_POINTOPOINT))
364 flags &= ~IFF_POINTOPOINT;
365 if (!(slave->flags&IFF_BROADCAST))
366 flags &= ~IFF_BROADCAST;
367 if (!(slave->flags&IFF_MULTICAST))
368 flags &= ~IFF_MULTICAST;
369 } while ((q = NEXT_SLAVE(q)) != m->slaves);
370
371 m->dev->mtu = mtu;
372 m->dev->flags = (m->dev->flags&~FMASK) | flags;
373 netif_start_queue(m->dev);
374 return 0;
375 }
376
377 static int teql_master_close(struct net_device *dev)
378 {
379 netif_stop_queue(dev);
380 return 0;
381 }
382
383 static struct net_device_stats *teql_master_stats(struct net_device *dev)
384 {
385 struct teql_master *m = netdev_priv(dev);
386 return &m->stats;
387 }
388
389 static int teql_master_mtu(struct net_device *dev, int new_mtu)
390 {
391 struct teql_master *m = netdev_priv(dev);
392 struct Qdisc *q;
393
394 if (new_mtu < 68)
395 return -EINVAL;
396
397 q = m->slaves;
398 if (q) {
399 do {
400 if (new_mtu > q->dev->mtu)
401 return -EINVAL;
402 } while ((q=NEXT_SLAVE(q)) != m->slaves);
403 }
404
405 dev->mtu = new_mtu;
406 return 0;
407 }
408
409 static __init void teql_master_setup(struct net_device *dev)
410 {
411 struct teql_master *master = netdev_priv(dev);
412 struct Qdisc_ops *ops = &master->qops;
413
414 master->dev = dev;
415 ops->priv_size = sizeof(struct teql_sched_data);
416
417 ops->enqueue = teql_enqueue;
418 ops->dequeue = teql_dequeue;
419 ops->requeue = teql_requeue;
420 ops->init = teql_qdisc_init;
421 ops->reset = teql_reset;
422 ops->destroy = teql_destroy;
423 ops->owner = THIS_MODULE;
424
425 dev->open = teql_master_open;
426 dev->hard_start_xmit = teql_master_xmit;
427 dev->stop = teql_master_close;
428 dev->get_stats = teql_master_stats;
429 dev->change_mtu = teql_master_mtu;
430 dev->type = ARPHRD_VOID;
431 dev->mtu = 1500;
432 dev->tx_queue_len = 100;
433 dev->flags = IFF_NOARP;
434 dev->hard_header_len = LL_MAX_HEADER;
435 SET_MODULE_OWNER(dev);
436 }
437
438 static LIST_HEAD(master_dev_list);
439 static int max_equalizers = 1;
440 module_param(max_equalizers, int, 0);
441 MODULE_PARM_DESC(max_equalizers, "Max number of link equalizers");
442
443 static int __init teql_init(void)
444 {
445 int i;
446 int err = -ENODEV;
447
448 for (i = 0; i < max_equalizers; i++) {
449 struct net_device *dev;
450 struct teql_master *master;
451
452 dev = alloc_netdev(sizeof(struct teql_master),
453 "teql%d", teql_master_setup);
454 if (!dev) {
455 err = -ENOMEM;
456 break;
457 }
458
459 if ((err = register_netdev(dev))) {
460 free_netdev(dev);
461 break;
462 }
463
464 master = netdev_priv(dev);
465
466 strlcpy(master->qops.id, dev->name, IFNAMSIZ);
467 err = register_qdisc(&master->qops);
468
469 if (err) {
470 unregister_netdev(dev);
471 free_netdev(dev);
472 break;
473 }
474
475 list_add_tail(&master->master_list, &master_dev_list);
476 }
477 return i ? 0 : err;
478 }
479
480 static void __exit teql_exit(void)
481 {
482 struct teql_master *master, *nxt;
483
484 list_for_each_entry_safe(master, nxt, &master_dev_list, master_list) {
485
486 list_del(&master->master_list);
487
488 unregister_qdisc(&master->qops);
489 unregister_netdev(master->dev);
490 free_netdev(master->dev);
491 }
492 }
493
494 module_init(teql_init);
495 module_exit(teql_exit);
496
497 MODULE_LICENSE("GPL");
Linux 2.6 libata-dev (mirror)