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fb: pvr2fb: Fix up section mismatch warnings.
[linux-2.6/x86.git] / net / sched / sch_teql.c
blobf05ad9a30b4cd67bfef9d956023367303ddb5343
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/string.h>
18 #include <linux/mm.h>
19 #include <linux/socket.h>
20 #include <linux/sockios.h>
21 #include <linux/in.h>
22 #include <linux/errno.h>
23 #include <linux/interrupt.h>
24 #include <linux/if_arp.h>
25 #include <linux/if_ether.h>
26 #include <linux/inet.h>
27 #include <linux/netdevice.h>
28 #include <linux/etherdevice.h>
29 #include <linux/notifier.h>
30 #include <linux/init.h>
31 #include <net/ip.h>
32 #include <net/route.h>
33 #include <linux/skbuff.h>
34 #include <linux/moduleparam.h>
35 #include <net/sock.h>
36 #include <net/pkt_sched.h>
37
38 /*
39 How to setup it.
40 ----------------
41
42 After loading this module you will find a new device teqlN
43 and new qdisc with the same name. To join a slave to the equalizer
44 you should just set this qdisc on a device f.e.
45
46 # tc qdisc add dev eth0 root teql0
47 # tc qdisc add dev eth1 root teql0
48
49 That's all. Full PnP 8)
50
51 Applicability.
52 --------------
53
54 1. Slave devices MUST be active devices, i.e., they must raise the tbusy
55 signal and generate EOI events. If you want to equalize virtual devices
56 like tunnels, use a normal eql device.
57 2. This device puts no limitations on physical slave characteristics
58 f.e. it will equalize 9600baud line and 100Mb ethernet perfectly :-)
59 Certainly, large difference in link speeds will make the resulting
60 eqalized link unusable, because of huge packet reordering.
61 I estimate an upper useful difference as ~10 times.
62 3. If the slave requires address resolution, only protocols using
63 neighbour cache (IPv4/IPv6) will work over the equalized link.
64 Other protocols are still allowed to use the slave device directly,
65 which will not break load balancing, though native slave
66 traffic will have the highest priority. */
67
68 struct teql_master
69 {
70 struct Qdisc_ops qops;
71 struct net_device *dev;
72 struct Qdisc *slaves;
73 struct list_head master_list;
74 struct net_device_stats stats;
75 };
76
77 struct teql_sched_data
78 {
79 struct Qdisc *next;
80 struct teql_master *m;
81 struct neighbour *ncache;
82 struct sk_buff_head q;
83 };
84
85 #define NEXT_SLAVE(q) (((struct teql_sched_data*)qdisc_priv(q))->next)
86
87 #define FMASK (IFF_BROADCAST|IFF_POINTOPOINT|IFF_BROADCAST)
88
89 /* "teql*" qdisc routines */
90
91 static int
92 teql_enqueue(struct sk_buff *skb, struct Qdisc* sch)
93 {
94 struct net_device *dev = sch->dev;
95 struct teql_sched_data *q = qdisc_priv(sch);
96
97 if (q->q.qlen < dev->tx_queue_len) {
98 __skb_queue_tail(&q->q, skb);
99 sch->bstats.bytes += skb->len;
100 sch->bstats.packets++;
101 return 0;
102 }
103
104 kfree_skb(skb);
105 sch->qstats.drops++;
106 return NET_XMIT_DROP;
107 }
108
109 static int
110 teql_requeue(struct sk_buff *skb, struct Qdisc* sch)
111 {
112 struct teql_sched_data *q = qdisc_priv(sch);
113
114 __skb_queue_head(&q->q, skb);
115 sch->qstats.requeues++;
116 return 0;
117 }
118
119 static struct sk_buff *
120 teql_dequeue(struct Qdisc* sch)
121 {
122 struct teql_sched_data *dat = qdisc_priv(sch);
123 struct sk_buff *skb;
124
125 skb = __skb_dequeue(&dat->q);
126 if (skb == NULL) {
127 struct net_device *m = dat->m->dev->qdisc->dev;
128 if (m) {
129 dat->m->slaves = sch;
130 netif_wake_queue(m);
131 }
132 }
133 sch->q.qlen = dat->q.qlen + dat->m->dev->qdisc->q.qlen;
134 return skb;
135 }
136
137 static __inline__ void
138 teql_neigh_release(struct neighbour *n)
139 {
140 if (n)
141 neigh_release(n);
142 }
143
144 static void
145 teql_reset(struct Qdisc* sch)
146 {
147 struct teql_sched_data *dat = qdisc_priv(sch);
148
149 skb_queue_purge(&dat->q);
150 sch->q.qlen = 0;
151 teql_neigh_release(xchg(&dat->ncache, NULL));
152 }
153
154 static void
155 teql_destroy(struct Qdisc* sch)
156 {
157 struct Qdisc *q, *prev;
158 struct teql_sched_data *dat = qdisc_priv(sch);
159 struct teql_master *master = dat->m;
160
161 if ((prev = master->slaves) != NULL) {
162 do {
163 q = NEXT_SLAVE(prev);
164 if (q == sch) {
165 NEXT_SLAVE(prev) = NEXT_SLAVE(q);
166 if (q == master->slaves) {
167 master->slaves = NEXT_SLAVE(q);
168 if (q == master->slaves) {
169 master->slaves = NULL;
170 spin_lock_bh(&master->dev->queue_lock);
171 qdisc_reset(master->dev->qdisc);
172 spin_unlock_bh(&master->dev->queue_lock);
173 }
174 }
175 skb_queue_purge(&dat->q);
176 teql_neigh_release(xchg(&dat->ncache, NULL));
177 break;
178 }
179
180 } while ((prev = q) != master->slaves);
181 }
182 }
183
184 static int teql_qdisc_init(struct Qdisc *sch, struct rtattr *opt)
185 {
186 struct net_device *dev = sch->dev;
187 struct teql_master *m = (struct teql_master*)sch->ops;
188 struct teql_sched_data *q = qdisc_priv(sch);
189
190 if (dev->hard_header_len > m->dev->hard_header_len)
191 return -EINVAL;
192
193 if (m->dev == dev)
194 return -ELOOP;
195
196 q->m = m;
197
198 skb_queue_head_init(&q->q);
199
200 if (m->slaves) {
201 if (m->dev->flags & IFF_UP) {
202 if ((m->dev->flags&IFF_POINTOPOINT && !(dev->flags&IFF_POINTOPOINT))
203 || (m->dev->flags&IFF_BROADCAST && !(dev->flags&IFF_BROADCAST))
204 || (m->dev->flags&IFF_MULTICAST && !(dev->flags&IFF_MULTICAST))
205 || dev->mtu < m->dev->mtu)
206 return -EINVAL;
207 } else {
208 if (!(dev->flags&IFF_POINTOPOINT))
209 m->dev->flags &= ~IFF_POINTOPOINT;
210 if (!(dev->flags&IFF_BROADCAST))
211 m->dev->flags &= ~IFF_BROADCAST;
212 if (!(dev->flags&IFF_MULTICAST))
213 m->dev->flags &= ~IFF_MULTICAST;
214 if (dev->mtu < m->dev->mtu)
215 m->dev->mtu = dev->mtu;
216 }
217 q->next = NEXT_SLAVE(m->slaves);
218 NEXT_SLAVE(m->slaves) = sch;
219 } else {
220 q->next = sch;
221 m->slaves = sch;
222 m->dev->mtu = dev->mtu;
223 m->dev->flags = (m->dev->flags&~FMASK)|(dev->flags&FMASK);
224 }
225 return 0;
226 }
227
228 /* "teql*" netdevice routines */
229
230 static int
231 __teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res, struct net_device *dev)
232 {
233 struct teql_sched_data *q = qdisc_priv(dev->qdisc);
234 struct neighbour *mn = skb->dst->neighbour;
235 struct neighbour *n = q->ncache;
236
237 if (mn->tbl == NULL)
238 return -EINVAL;
239 if (n && n->tbl == mn->tbl &&
240 memcmp(n->primary_key, mn->primary_key, mn->tbl->key_len) == 0) {
241 atomic_inc(&n->refcnt);
242 } else {
243 n = __neigh_lookup_errno(mn->tbl, mn->primary_key, dev);
244 if (IS_ERR(n))
245 return PTR_ERR(n);
246 }
247 if (neigh_event_send(n, skb_res) == 0) {
248 int err;
249 read_lock(&n->lock);
250 err = dev->hard_header(skb, dev, ntohs(skb->protocol), n->ha, NULL, skb->len);
251 read_unlock(&n->lock);
252 if (err < 0) {
253 neigh_release(n);
254 return -EINVAL;
255 }
256 teql_neigh_release(xchg(&q->ncache, n));
257 return 0;
258 }
259 neigh_release(n);
260 return (skb_res == NULL) ? -EAGAIN : 1;
261 }
262
263 static __inline__ int
264 teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res, struct net_device *dev)
265 {
266 if (dev->hard_header == NULL ||
267 skb->dst == NULL ||
268 skb->dst->neighbour == NULL)
269 return 0;
270 return __teql_resolve(skb, skb_res, dev);
271 }
272
273 static int teql_master_xmit(struct sk_buff *skb, struct net_device *dev)
274 {
275 struct teql_master *master = netdev_priv(dev);
276 struct Qdisc *start, *q;
277 int busy;
278 int nores;
279 int len = skb->len;
280 struct sk_buff *skb_res = NULL;
281
282 start = master->slaves;
283
284 restart:
285 nores = 0;
286 busy = 0;
287
288 if ((q = start) == NULL)
289 goto drop;
290
291 do {
292 struct net_device *slave = q->dev;
293
294 if (slave->qdisc_sleeping != q)
295 continue;
296 if (netif_queue_stopped(slave) || ! netif_running(slave)) {
297 busy = 1;
298 continue;
299 }
300
301 switch (teql_resolve(skb, skb_res, slave)) {
302 case 0:
303 if (netif_tx_trylock(slave)) {
304 if (!netif_queue_stopped(slave) &&
305 slave->hard_start_xmit(skb, slave) == 0) {
306 netif_tx_unlock(slave);
307 master->slaves = NEXT_SLAVE(q);
308 netif_wake_queue(dev);
309 master->stats.tx_packets++;
310 master->stats.tx_bytes += len;
311 return 0;
312 }
313 netif_tx_unlock(slave);
314 }
315 if (netif_queue_stopped(dev))
316 busy = 1;
317 break;
318 case 1:
319 master->slaves = NEXT_SLAVE(q);
320 return 0;
321 default:
322 nores = 1;
323 break;
324 }
325 __skb_pull(skb, skb_network_offset(skb));
326 } while ((q = NEXT_SLAVE(q)) != start);
327
328 if (nores && skb_res == NULL) {
329 skb_res = skb;
330 goto restart;
331 }
332
333 if (busy) {
334 netif_stop_queue(dev);
335 return 1;
336 }
337 master->stats.tx_errors++;
338
339 drop:
340 master->stats.tx_dropped++;
341 dev_kfree_skb(skb);
342 return 0;
343 }
344
345 static int teql_master_open(struct net_device *dev)
346 {
347 struct Qdisc * q;
348 struct teql_master *m = netdev_priv(dev);
349 int mtu = 0xFFFE;
350 unsigned flags = IFF_NOARP|IFF_MULTICAST;
351
352 if (m->slaves == NULL)
353 return -EUNATCH;
354
355 flags = FMASK;
356
357 q = m->slaves;
358 do {
359 struct net_device *slave = q->dev;
360
361 if (slave == NULL)
362 return -EUNATCH;
363
364 if (slave->mtu < mtu)
365 mtu = slave->mtu;
366 if (slave->hard_header_len > LL_MAX_HEADER)
367 return -EINVAL;
368
369 /* If all the slaves are BROADCAST, master is BROADCAST
370 If all the slaves are PtP, master is PtP
371 Otherwise, master is NBMA.
372 */
373 if (!(slave->flags&IFF_POINTOPOINT))
374 flags &= ~IFF_POINTOPOINT;
375 if (!(slave->flags&IFF_BROADCAST))
376 flags &= ~IFF_BROADCAST;
377 if (!(slave->flags&IFF_MULTICAST))
378 flags &= ~IFF_MULTICAST;
379 } while ((q = NEXT_SLAVE(q)) != m->slaves);
380
381 m->dev->mtu = mtu;
382 m->dev->flags = (m->dev->flags&~FMASK) | flags;
383 netif_start_queue(m->dev);
384 return 0;
385 }
386
387 static int teql_master_close(struct net_device *dev)
388 {
389 netif_stop_queue(dev);
390 return 0;
391 }
392
393 static struct net_device_stats *teql_master_stats(struct net_device *dev)
394 {
395 struct teql_master *m = netdev_priv(dev);
396 return &m->stats;
397 }
398
399 static int teql_master_mtu(struct net_device *dev, int new_mtu)
400 {
401 struct teql_master *m = netdev_priv(dev);
402 struct Qdisc *q;
403
404 if (new_mtu < 68)
405 return -EINVAL;
406
407 q = m->slaves;
408 if (q) {
409 do {
410 if (new_mtu > q->dev->mtu)
411 return -EINVAL;
412 } while ((q=NEXT_SLAVE(q)) != m->slaves);
413 }
414
415 dev->mtu = new_mtu;
416 return 0;
417 }
418
419 static __init void teql_master_setup(struct net_device *dev)
420 {
421 struct teql_master *master = netdev_priv(dev);
422 struct Qdisc_ops *ops = &master->qops;
423
424 master->dev = dev;
425 ops->priv_size = sizeof(struct teql_sched_data);
426
427 ops->enqueue = teql_enqueue;
428 ops->dequeue = teql_dequeue;
429 ops->requeue = teql_requeue;
430 ops->init = teql_qdisc_init;
431 ops->reset = teql_reset;
432 ops->destroy = teql_destroy;
433 ops->owner = THIS_MODULE;
434
435 dev->open = teql_master_open;
436 dev->hard_start_xmit = teql_master_xmit;
437 dev->stop = teql_master_close;
438 dev->get_stats = teql_master_stats;
439 dev->change_mtu = teql_master_mtu;
440 dev->type = ARPHRD_VOID;
441 dev->mtu = 1500;
442 dev->tx_queue_len = 100;
443 dev->flags = IFF_NOARP;
444 dev->hard_header_len = LL_MAX_HEADER;
445 SET_MODULE_OWNER(dev);
446 }
447
448 static LIST_HEAD(master_dev_list);
449 static int max_equalizers = 1;
450 module_param(max_equalizers, int, 0);
451 MODULE_PARM_DESC(max_equalizers, "Max number of link equalizers");
452
453 static int __init teql_init(void)
454 {
455 int i;
456 int err = -ENODEV;
457
458 for (i = 0; i < max_equalizers; i++) {
459 struct net_device *dev;
460 struct teql_master *master;
461
462 dev = alloc_netdev(sizeof(struct teql_master),
463 "teql%d", teql_master_setup);
464 if (!dev) {
465 err = -ENOMEM;
466 break;
467 }
468
469 if ((err = register_netdev(dev))) {
470 free_netdev(dev);
471 break;
472 }
473
474 master = netdev_priv(dev);
475
476 strlcpy(master->qops.id, dev->name, IFNAMSIZ);
477 err = register_qdisc(&master->qops);
478
479 if (err) {
480 unregister_netdev(dev);
481 free_netdev(dev);
482 break;
483 }
484
485 list_add_tail(&master->master_list, &master_dev_list);
486 }
487 return i ? 0 : err;
488 }
489
490 static void __exit teql_exit(void)
491 {
492 struct teql_master *master, *nxt;
493
494 list_for_each_entry_safe(master, nxt, &master_dev_list, master_list) {
495
496 list_del(&master->master_list);
497
498 unregister_qdisc(&master->qops);
499 unregister_netdev(master->dev);
500 free_netdev(master->dev);
501 }
502 }
503
504 module_init(teql_init);
505 module_exit(teql_exit);
506
507 MODULE_LICENSE("GPL");
x86 "subsystem" repository