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Driver Core: Move virtual_device_parent() to core.c
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / net / sched / sch_teql.c
blob4c16ad57a3e49141335a2812b4c7bc3e976e9b46
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 <asm/uaccess.h>
13 #include <asm/system.h>
14 #include <linux/bitops.h>
15 #include <linux/types.h>
16 #include <linux/kernel.h>
17 #include <linux/sched.h>
18 #include <linux/string.h>
19 #include <linux/mm.h>
20 #include <linux/socket.h>
21 #include <linux/sockios.h>
22 #include <linux/in.h>
23 #include <linux/errno.h>
24 #include <linux/interrupt.h>
25 #include <linux/if_arp.h>
26 #include <linux/if_ether.h>
27 #include <linux/inet.h>
28 #include <linux/netdevice.h>
29 #include <linux/etherdevice.h>
30 #include <linux/notifier.h>
31 #include <linux/init.h>
32 #include <net/ip.h>
33 #include <net/route.h>
34 #include <linux/skbuff.h>
35 #include <linux/moduleparam.h>
36 #include <net/sock.h>
37 #include <net/pkt_sched.h>
38
39 /*
40 How to setup it.
41 ----------------
42
43 After loading this module you will find a new device teqlN
44 and new qdisc with the same name. To join a slave to the equalizer
45 you should just set this qdisc on a device f.e.
46
47 # tc qdisc add dev eth0 root teql0
48 # tc qdisc add dev eth1 root teql0
49
50 That's all. Full PnP 8)
51
52 Applicability.
53 --------------
54
55 1. Slave devices MUST be active devices, i.e., they must raise the tbusy
56 signal and generate EOI events. If you want to equalize virtual devices
57 like tunnels, use a normal eql device.
58 2. This device puts no limitations on physical slave characteristics
59 f.e. it will equalize 9600baud line and 100Mb ethernet perfectly :-)
60 Certainly, large difference in link speeds will make the resulting
61 eqalized link unusable, because of huge packet reordering.
62 I estimate an upper useful difference as ~10 times.
63 3. If the slave requires address resolution, only protocols using
64 neighbour cache (IPv4/IPv6) will work over the equalized link.
65 Other protocols are still allowed to use the slave device directly,
66 which will not break load balancing, though native slave
67 traffic will have the highest priority. */
68
69 struct teql_master
70 {
71 struct Qdisc_ops qops;
72 struct net_device *dev;
73 struct Qdisc *slaves;
74 struct list_head master_list;
75 struct net_device_stats stats;
76 };
77
78 struct teql_sched_data
79 {
80 struct Qdisc *next;
81 struct teql_master *m;
82 struct neighbour *ncache;
83 struct sk_buff_head q;
84 };
85
86 #define NEXT_SLAVE(q) (((struct teql_sched_data*)qdisc_priv(q))->next)
87
88 #define FMASK (IFF_BROADCAST|IFF_POINTOPOINT|IFF_BROADCAST)
89
90 /* "teql*" qdisc routines */
91
92 static int
93 teql_enqueue(struct sk_buff *skb, struct Qdisc* sch)
94 {
95 struct net_device *dev = sch->dev;
96 struct teql_sched_data *q = qdisc_priv(sch);
97
98 __skb_queue_tail(&q->q, skb);
99 if (q->q.qlen <= dev->tx_queue_len) {
100 sch->bstats.bytes += skb->len;
101 sch->bstats.packets++;
102 return 0;
103 }
104
105 __skb_unlink(skb, &q->q);
106 kfree_skb(skb);
107 sch->qstats.drops++;
108 return NET_XMIT_DROP;
109 }
110
111 static int
112 teql_requeue(struct sk_buff *skb, struct Qdisc* sch)
113 {
114 struct teql_sched_data *q = qdisc_priv(sch);
115
116 __skb_queue_head(&q->q, skb);
117 sch->qstats.requeues++;
118 return 0;
119 }
120
121 static struct sk_buff *
122 teql_dequeue(struct Qdisc* sch)
123 {
124 struct teql_sched_data *dat = qdisc_priv(sch);
125 struct sk_buff *skb;
126
127 skb = __skb_dequeue(&dat->q);
128 if (skb == NULL) {
129 struct net_device *m = dat->m->dev->qdisc->dev;
130 if (m) {
131 dat->m->slaves = sch;
132 netif_wake_queue(m);
133 }
134 }
135 sch->q.qlen = dat->q.qlen + dat->m->dev->qdisc->q.qlen;
136 return skb;
137 }
138
139 static __inline__ void
140 teql_neigh_release(struct neighbour *n)
141 {
142 if (n)
143 neigh_release(n);
144 }
145
146 static void
147 teql_reset(struct Qdisc* sch)
148 {
149 struct teql_sched_data *dat = qdisc_priv(sch);
150
151 skb_queue_purge(&dat->q);
152 sch->q.qlen = 0;
153 teql_neigh_release(xchg(&dat->ncache, NULL));
154 }
155
156 static void
157 teql_destroy(struct Qdisc* sch)
158 {
159 struct Qdisc *q, *prev;
160 struct teql_sched_data *dat = qdisc_priv(sch);
161 struct teql_master *master = dat->m;
162
163 if ((prev = master->slaves) != NULL) {
164 do {
165 q = NEXT_SLAVE(prev);
166 if (q == sch) {
167 NEXT_SLAVE(prev) = NEXT_SLAVE(q);
168 if (q == master->slaves) {
169 master->slaves = NEXT_SLAVE(q);
170 if (q == master->slaves) {
171 master->slaves = NULL;
172 spin_lock_bh(&master->dev->queue_lock);
173 qdisc_reset(master->dev->qdisc);
174 spin_unlock_bh(&master->dev->queue_lock);
175 }
176 }
177 skb_queue_purge(&dat->q);
178 teql_neigh_release(xchg(&dat->ncache, NULL));
179 break;
180 }
181
182 } while ((prev = q) != master->slaves);
183 }
184 }
185
186 static int teql_qdisc_init(struct Qdisc *sch, struct rtattr *opt)
187 {
188 struct net_device *dev = sch->dev;
189 struct teql_master *m = (struct teql_master*)sch->ops;
190 struct teql_sched_data *q = qdisc_priv(sch);
191
192 if (dev->hard_header_len > m->dev->hard_header_len)
193 return -EINVAL;
194
195 if (m->dev == dev)
196 return -ELOOP;
197
198 q->m = m;
199
200 skb_queue_head_init(&q->q);
201
202 if (m->slaves) {
203 if (m->dev->flags & IFF_UP) {
204 if ((m->dev->flags&IFF_POINTOPOINT && !(dev->flags&IFF_POINTOPOINT))
205 || (m->dev->flags&IFF_BROADCAST && !(dev->flags&IFF_BROADCAST))
206 || (m->dev->flags&IFF_MULTICAST && !(dev->flags&IFF_MULTICAST))
207 || dev->mtu < m->dev->mtu)
208 return -EINVAL;
209 } else {
210 if (!(dev->flags&IFF_POINTOPOINT))
211 m->dev->flags &= ~IFF_POINTOPOINT;
212 if (!(dev->flags&IFF_BROADCAST))
213 m->dev->flags &= ~IFF_BROADCAST;
214 if (!(dev->flags&IFF_MULTICAST))
215 m->dev->flags &= ~IFF_MULTICAST;
216 if (dev->mtu < m->dev->mtu)
217 m->dev->mtu = dev->mtu;
218 }
219 q->next = NEXT_SLAVE(m->slaves);
220 NEXT_SLAVE(m->slaves) = sch;
221 } else {
222 q->next = sch;
223 m->slaves = sch;
224 m->dev->mtu = dev->mtu;
225 m->dev->flags = (m->dev->flags&~FMASK)|(dev->flags&FMASK);
226 }
227 return 0;
228 }
229
230 /* "teql*" netdevice routines */
231
232 static int
233 __teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res, struct net_device *dev)
234 {
235 struct teql_sched_data *q = qdisc_priv(dev->qdisc);
236 struct neighbour *mn = skb->dst->neighbour;
237 struct neighbour *n = q->ncache;
238
239 if (mn->tbl == NULL)
240 return -EINVAL;
241 if (n && n->tbl == mn->tbl &&
242 memcmp(n->primary_key, mn->primary_key, mn->tbl->key_len) == 0) {
243 atomic_inc(&n->refcnt);
244 } else {
245 n = __neigh_lookup_errno(mn->tbl, mn->primary_key, dev);
246 if (IS_ERR(n))
247 return PTR_ERR(n);
248 }
249 if (neigh_event_send(n, skb_res) == 0) {
250 int err;
251 read_lock(&n->lock);
252 err = dev->hard_header(skb, dev, ntohs(skb->protocol), n->ha, NULL, skb->len);
253 read_unlock(&n->lock);
254 if (err < 0) {
255 neigh_release(n);
256 return -EINVAL;
257 }
258 teql_neigh_release(xchg(&q->ncache, n));
259 return 0;
260 }
261 neigh_release(n);
262 return (skb_res == NULL) ? -EAGAIN : 1;
263 }
264
265 static __inline__ int
266 teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res, struct net_device *dev)
267 {
268 if (dev->hard_header == 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 len = skb->len;
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 = q->dev;
295
296 if (slave->qdisc_sleeping != q)
297 continue;
298 if (netif_queue_stopped(slave) || ! 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)) {
306 if (!netif_queue_stopped(slave) &&
307 slave->hard_start_xmit(skb, slave) == 0) {
308 netif_tx_unlock(slave);
309 master->slaves = NEXT_SLAVE(q);
310 netif_wake_queue(dev);
311 master->stats.tx_packets++;
312 master->stats.tx_bytes += len;
313 return 0;
314 }
315 netif_tx_unlock(slave);
316 }
317 if (netif_queue_stopped(dev))
318 busy = 1;
319 break;
320 case 1:
321 master->slaves = NEXT_SLAVE(q);
322 return 0;
323 default:
324 nores = 1;
325 break;
326 }
327 __skb_pull(skb, skb->nh.raw - skb->data);
328 } while ((q = NEXT_SLAVE(q)) != start);
329
330 if (nores && skb_res == NULL) {
331 skb_res = skb;
332 goto restart;
333 }
334
335 if (busy) {
336 netif_stop_queue(dev);
337 return 1;
338 }
339 master->stats.tx_errors++;
340
341 drop:
342 master->stats.tx_dropped++;
343 dev_kfree_skb(skb);
344 return 0;
345 }
346
347 static int teql_master_open(struct net_device *dev)
348 {
349 struct Qdisc * q;
350 struct teql_master *m = netdev_priv(dev);
351 int mtu = 0xFFFE;
352 unsigned flags = IFF_NOARP|IFF_MULTICAST;
353
354 if (m->slaves == NULL)
355 return -EUNATCH;
356
357 flags = FMASK;
358
359 q = m->slaves;
360 do {
361 struct net_device *slave = q->dev;
362
363 if (slave == NULL)
364 return -EUNATCH;
365
366 if (slave->mtu < mtu)
367 mtu = slave->mtu;
368 if (slave->hard_header_len > LL_MAX_HEADER)
369 return -EINVAL;
370
371 /* If all the slaves are BROADCAST, master is BROADCAST
372 If all the slaves are PtP, master is PtP
373 Otherwise, master is NBMA.
374 */
375 if (!(slave->flags&IFF_POINTOPOINT))
376 flags &= ~IFF_POINTOPOINT;
377 if (!(slave->flags&IFF_BROADCAST))
378 flags &= ~IFF_BROADCAST;
379 if (!(slave->flags&IFF_MULTICAST))
380 flags &= ~IFF_MULTICAST;
381 } while ((q = NEXT_SLAVE(q)) != m->slaves);
382
383 m->dev->mtu = mtu;
384 m->dev->flags = (m->dev->flags&~FMASK) | flags;
385 netif_start_queue(m->dev);
386 return 0;
387 }
388
389 static int teql_master_close(struct net_device *dev)
390 {
391 netif_stop_queue(dev);
392 return 0;
393 }
394
395 static struct net_device_stats *teql_master_stats(struct net_device *dev)
396 {
397 struct teql_master *m = netdev_priv(dev);
398 return &m->stats;
399 }
400
401 static int teql_master_mtu(struct net_device *dev, int new_mtu)
402 {
403 struct teql_master *m = netdev_priv(dev);
404 struct Qdisc *q;
405
406 if (new_mtu < 68)
407 return -EINVAL;
408
409 q = m->slaves;
410 if (q) {
411 do {
412 if (new_mtu > q->dev->mtu)
413 return -EINVAL;
414 } while ((q=NEXT_SLAVE(q)) != m->slaves);
415 }
416
417 dev->mtu = new_mtu;
418 return 0;
419 }
420
421 static __init void teql_master_setup(struct net_device *dev)
422 {
423 struct teql_master *master = netdev_priv(dev);
424 struct Qdisc_ops *ops = &master->qops;
425
426 master->dev = dev;
427 ops->priv_size = sizeof(struct teql_sched_data);
428
429 ops->enqueue = teql_enqueue;
430 ops->dequeue = teql_dequeue;
431 ops->requeue = teql_requeue;
432 ops->init = teql_qdisc_init;
433 ops->reset = teql_reset;
434 ops->destroy = teql_destroy;
435 ops->owner = THIS_MODULE;
436
437 dev->open = teql_master_open;
438 dev->hard_start_xmit = teql_master_xmit;
439 dev->stop = teql_master_close;
440 dev->get_stats = teql_master_stats;
441 dev->change_mtu = teql_master_mtu;
442 dev->type = ARPHRD_VOID;
443 dev->mtu = 1500;
444 dev->tx_queue_len = 100;
445 dev->flags = IFF_NOARP;
446 dev->hard_header_len = LL_MAX_HEADER;
447 SET_MODULE_OWNER(dev);
448 }
449
450 static LIST_HEAD(master_dev_list);
451 static int max_equalizers = 1;
452 module_param(max_equalizers, int, 0);
453 MODULE_PARM_DESC(max_equalizers, "Max number of link equalizers");
454
455 static int __init teql_init(void)
456 {
457 int i;
458 int err = -ENODEV;
459
460 for (i = 0; i < max_equalizers; i++) {
461 struct net_device *dev;
462 struct teql_master *master;
463
464 dev = alloc_netdev(sizeof(struct teql_master),
465 "teql%d", teql_master_setup);
466 if (!dev) {
467 err = -ENOMEM;
468 break;
469 }
470
471 if ((err = register_netdev(dev))) {
472 free_netdev(dev);
473 break;
474 }
475
476 master = netdev_priv(dev);
477
478 strlcpy(master->qops.id, dev->name, IFNAMSIZ);
479 err = register_qdisc(&master->qops);
480
481 if (err) {
482 unregister_netdev(dev);
483 free_netdev(dev);
484 break;
485 }
486
487 list_add_tail(&master->master_list, &master_dev_list);
488 }
489 return i ? 0 : err;
490 }
491
492 static void __exit teql_exit(void)
493 {
494 struct teql_master *master, *nxt;
495
496 list_for_each_entry_safe(master, nxt, &master_dev_list, master_list) {
497
498 list_del(&master->master_list);
499
500 unregister_qdisc(&master->qops);
501 unregister_netdev(master->dev);
502 free_netdev(master->dev);
503 }
504 }
505
506 module_init(teql_init);
507 module_exit(teql_exit);
508
509 MODULE_LICENSE("GPL");
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