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hwmon: (jc42) do not allow writing to locked registers
[linux-2.6.git] / net / sched / sch_teql.c
blobd84e7329660fb5f21e5e87d11fae435e27907a8b
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 {
58 struct Qdisc_ops qops;
59 struct net_device *dev;
60 struct Qdisc *slaves;
61 struct list_head master_list;
62 unsigned long tx_bytes;
63 unsigned long tx_packets;
64 unsigned long tx_errors;
65 unsigned long tx_dropped;
66 };
67
68 struct teql_sched_data
69 {
70 struct Qdisc *next;
71 struct teql_master *m;
72 struct neighbour *ncache;
73 struct sk_buff_head q;
74 };
75
76 #define NEXT_SLAVE(q) (((struct teql_sched_data*)qdisc_priv(q))->next)
77
78 #define FMASK (IFF_BROADCAST|IFF_POINTOPOINT)
79
80 /* "teql*" qdisc routines */
81
82 static int
83 teql_enqueue(struct sk_buff *skb, struct Qdisc* sch)
84 {
85 struct net_device *dev = qdisc_dev(sch);
86 struct teql_sched_data *q = qdisc_priv(sch);
87
88 if (q->q.qlen < dev->tx_queue_len) {
89 __skb_queue_tail(&q->q, skb);
90 return NET_XMIT_SUCCESS;
91 }
92
93 kfree_skb(skb);
94 sch->qstats.drops++;
95 return NET_XMIT_DROP;
96 }
97
98 static struct sk_buff *
99 teql_dequeue(struct Qdisc* sch)
100 {
101 struct teql_sched_data *dat = qdisc_priv(sch);
102 struct netdev_queue *dat_queue;
103 struct sk_buff *skb;
104
105 skb = __skb_dequeue(&dat->q);
106 dat_queue = netdev_get_tx_queue(dat->m->dev, 0);
107 if (skb == NULL) {
108 struct net_device *m = qdisc_dev(dat_queue->qdisc);
109 if (m) {
110 dat->m->slaves = sch;
111 netif_wake_queue(m);
112 }
113 } else {
114 qdisc_bstats_update(sch, skb);
115 }
116 sch->q.qlen = dat->q.qlen + dat_queue->qdisc->q.qlen;
117 return skb;
118 }
119
120 static struct sk_buff *
121 teql_peek(struct Qdisc* sch)
122 {
123 /* teql is meant to be used as root qdisc */
124 return NULL;
125 }
126
127 static __inline__ void
128 teql_neigh_release(struct neighbour *n)
129 {
130 if (n)
131 neigh_release(n);
132 }
133
134 static void
135 teql_reset(struct Qdisc* sch)
136 {
137 struct teql_sched_data *dat = qdisc_priv(sch);
138
139 skb_queue_purge(&dat->q);
140 sch->q.qlen = 0;
141 teql_neigh_release(xchg(&dat->ncache, NULL));
142 }
143
144 static void
145 teql_destroy(struct Qdisc* sch)
146 {
147 struct Qdisc *q, *prev;
148 struct teql_sched_data *dat = qdisc_priv(sch);
149 struct teql_master *master = dat->m;
150
151 if ((prev = master->slaves) != NULL) {
152 do {
153 q = NEXT_SLAVE(prev);
154 if (q == sch) {
155 NEXT_SLAVE(prev) = NEXT_SLAVE(q);
156 if (q == master->slaves) {
157 master->slaves = NEXT_SLAVE(q);
158 if (q == master->slaves) {
159 struct netdev_queue *txq;
160 spinlock_t *root_lock;
161
162 txq = netdev_get_tx_queue(master->dev, 0);
163 master->slaves = NULL;
164
165 root_lock = qdisc_root_sleeping_lock(txq->qdisc);
166 spin_lock_bh(root_lock);
167 qdisc_reset(txq->qdisc);
168 spin_unlock_bh(root_lock);
169 }
170 }
171 skb_queue_purge(&dat->q);
172 teql_neigh_release(xchg(&dat->ncache, NULL));
173 break;
174 }
175
176 } while ((prev = q) != master->slaves);
177 }
178 }
179
180 static int teql_qdisc_init(struct Qdisc *sch, struct nlattr *opt)
181 {
182 struct net_device *dev = qdisc_dev(sch);
183 struct teql_master *m = (struct teql_master*)sch->ops;
184 struct teql_sched_data *q = qdisc_priv(sch);
185
186 if (dev->hard_header_len > m->dev->hard_header_len)
187 return -EINVAL;
188
189 if (m->dev == dev)
190 return -ELOOP;
191
192 q->m = m;
193
194 skb_queue_head_init(&q->q);
195
196 if (m->slaves) {
197 if (m->dev->flags & IFF_UP) {
198 if ((m->dev->flags & IFF_POINTOPOINT &&
199 !(dev->flags & IFF_POINTOPOINT)) ||
200 (m->dev->flags & IFF_BROADCAST &&
201 !(dev->flags & IFF_BROADCAST)) ||
202 (m->dev->flags & IFF_MULTICAST &&
203 !(dev->flags & IFF_MULTICAST)) ||
204 dev->mtu < m->dev->mtu)
205 return -EINVAL;
206 } else {
207 if (!(dev->flags&IFF_POINTOPOINT))
208 m->dev->flags &= ~IFF_POINTOPOINT;
209 if (!(dev->flags&IFF_BROADCAST))
210 m->dev->flags &= ~IFF_BROADCAST;
211 if (!(dev->flags&IFF_MULTICAST))
212 m->dev->flags &= ~IFF_MULTICAST;
213 if (dev->mtu < m->dev->mtu)
214 m->dev->mtu = dev->mtu;
215 }
216 q->next = NEXT_SLAVE(m->slaves);
217 NEXT_SLAVE(m->slaves) = sch;
218 } else {
219 q->next = sch;
220 m->slaves = sch;
221 m->dev->mtu = dev->mtu;
222 m->dev->flags = (m->dev->flags&~FMASK)|(dev->flags&FMASK);
223 }
224 return 0;
225 }
226
227
228 static int
229 __teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res, struct net_device *dev)
230 {
231 struct netdev_queue *dev_queue = netdev_get_tx_queue(dev, 0);
232 struct teql_sched_data *q = qdisc_priv(dev_queue->qdisc);
233 struct neighbour *mn = skb_dst(skb)->neighbour;
234 struct neighbour *n = q->ncache;
235
236 if (mn->tbl == NULL)
237 return -EINVAL;
238 if (n && n->tbl == mn->tbl &&
239 memcmp(n->primary_key, mn->primary_key, mn->tbl->key_len) == 0) {
240 atomic_inc(&n->refcnt);
241 } else {
242 n = __neigh_lookup_errno(mn->tbl, mn->primary_key, dev);
243 if (IS_ERR(n))
244 return PTR_ERR(n);
245 }
246 if (neigh_event_send(n, skb_res) == 0) {
247 int err;
248 char haddr[MAX_ADDR_LEN];
249
250 neigh_ha_snapshot(haddr, n, dev);
251 err = dev_hard_header(skb, dev, ntohs(skb->protocol), haddr,
252 NULL, skb->len);
253
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 teql_resolve(struct sk_buff *skb,
266 struct sk_buff *skb_res, struct net_device *dev)
267 {
268 struct netdev_queue *txq = netdev_get_tx_queue(dev, 0);
269 if (txq->qdisc == &noop_qdisc)
270 return -ENODEV;
271
272 if (dev->header_ops == NULL ||
273 skb_dst(skb) == NULL ||
274 skb_dst(skb)->neighbour == NULL)
275 return 0;
276 return __teql_resolve(skb, skb_res, dev);
277 }
278
279 static netdev_tx_t teql_master_xmit(struct sk_buff *skb, struct net_device *dev)
280 {
281 struct teql_master *master = netdev_priv(dev);
282 struct Qdisc *start, *q;
283 int busy;
284 int nores;
285 int subq = skb_get_queue_mapping(skb);
286 struct sk_buff *skb_res = NULL;
287
288 start = master->slaves;
289
290 restart:
291 nores = 0;
292 busy = 0;
293
294 if ((q = start) == NULL)
295 goto drop;
296
297 do {
298 struct net_device *slave = qdisc_dev(q);
299 struct netdev_queue *slave_txq = netdev_get_tx_queue(slave, 0);
300 const struct net_device_ops *slave_ops = slave->netdev_ops;
301
302 if (slave_txq->qdisc_sleeping != q)
303 continue;
304 if (__netif_subqueue_stopped(slave, subq) ||
305 !netif_running(slave)) {
306 busy = 1;
307 continue;
308 }
309
310 switch (teql_resolve(skb, skb_res, slave)) {
311 case 0:
312 if (__netif_tx_trylock(slave_txq)) {
313 unsigned int length = qdisc_pkt_len(skb);
314
315 if (!netif_tx_queue_frozen_or_stopped(slave_txq) &&
316 slave_ops->ndo_start_xmit(skb, slave) == NETDEV_TX_OK) {
317 txq_trans_update(slave_txq);
318 __netif_tx_unlock(slave_txq);
319 master->slaves = NEXT_SLAVE(q);
320 netif_wake_queue(dev);
321 master->tx_packets++;
322 master->tx_bytes += length;
323 return NETDEV_TX_OK;
324 }
325 __netif_tx_unlock(slave_txq);
326 }
327 if (netif_queue_stopped(dev))
328 busy = 1;
329 break;
330 case 1:
331 master->slaves = NEXT_SLAVE(q);
332 return NETDEV_TX_OK;
333 default:
334 nores = 1;
335 break;
336 }
337 __skb_pull(skb, skb_network_offset(skb));
338 } while ((q = NEXT_SLAVE(q)) != start);
339
340 if (nores && skb_res == NULL) {
341 skb_res = skb;
342 goto restart;
343 }
344
345 if (busy) {
346 netif_stop_queue(dev);
347 return NETDEV_TX_BUSY;
348 }
349 master->tx_errors++;
350
351 drop:
352 master->tx_dropped++;
353 dev_kfree_skb(skb);
354 return NETDEV_TX_OK;
355 }
356
357 static int teql_master_open(struct net_device *dev)
358 {
359 struct Qdisc * q;
360 struct teql_master *m = netdev_priv(dev);
361 int mtu = 0xFFFE;
362 unsigned flags = IFF_NOARP|IFF_MULTICAST;
363
364 if (m->slaves == NULL)
365 return -EUNATCH;
366
367 flags = FMASK;
368
369 q = m->slaves;
370 do {
371 struct net_device *slave = qdisc_dev(q);
372
373 if (slave == NULL)
374 return -EUNATCH;
375
376 if (slave->mtu < mtu)
377 mtu = slave->mtu;
378 if (slave->hard_header_len > LL_MAX_HEADER)
379 return -EINVAL;
380
381 /* If all the slaves are BROADCAST, master is BROADCAST
382 If all the slaves are PtP, master is PtP
383 Otherwise, master is NBMA.
384 */
385 if (!(slave->flags&IFF_POINTOPOINT))
386 flags &= ~IFF_POINTOPOINT;
387 if (!(slave->flags&IFF_BROADCAST))
388 flags &= ~IFF_BROADCAST;
389 if (!(slave->flags&IFF_MULTICAST))
390 flags &= ~IFF_MULTICAST;
391 } while ((q = NEXT_SLAVE(q)) != m->slaves);
392
393 m->dev->mtu = mtu;
394 m->dev->flags = (m->dev->flags&~FMASK) | flags;
395 netif_start_queue(m->dev);
396 return 0;
397 }
398
399 static int teql_master_close(struct net_device *dev)
400 {
401 netif_stop_queue(dev);
402 return 0;
403 }
404
405 static struct rtnl_link_stats64 *teql_master_stats64(struct net_device *dev,
406 struct rtnl_link_stats64 *stats)
407 {
408 struct teql_master *m = netdev_priv(dev);
409
410 stats->tx_packets = m->tx_packets;
411 stats->tx_bytes = m->tx_bytes;
412 stats->tx_errors = m->tx_errors;
413 stats->tx_dropped = m->tx_dropped;
414 return stats;
415 }
416
417 static int teql_master_mtu(struct net_device *dev, int new_mtu)
418 {
419 struct teql_master *m = netdev_priv(dev);
420 struct Qdisc *q;
421
422 if (new_mtu < 68)
423 return -EINVAL;
424
425 q = m->slaves;
426 if (q) {
427 do {
428 if (new_mtu > qdisc_dev(q)->mtu)
429 return -EINVAL;
430 } while ((q=NEXT_SLAVE(q)) != m->slaves);
431 }
432
433 dev->mtu = new_mtu;
434 return 0;
435 }
436
437 static const struct net_device_ops teql_netdev_ops = {
438 .ndo_open = teql_master_open,
439 .ndo_stop = teql_master_close,
440 .ndo_start_xmit = teql_master_xmit,
441 .ndo_get_stats64 = teql_master_stats64,
442 .ndo_change_mtu = teql_master_mtu,
443 };
444
445 static __init void teql_master_setup(struct net_device *dev)
446 {
447 struct teql_master *master = netdev_priv(dev);
448 struct Qdisc_ops *ops = &master->qops;
449
450 master->dev = dev;
451 ops->priv_size = sizeof(struct teql_sched_data);
452
453 ops->enqueue = teql_enqueue;
454 ops->dequeue = teql_dequeue;
455 ops->peek = teql_peek;
456 ops->init = teql_qdisc_init;
457 ops->reset = teql_reset;
458 ops->destroy = teql_destroy;
459 ops->owner = THIS_MODULE;
460
461 dev->netdev_ops = &teql_netdev_ops;
462 dev->type = ARPHRD_VOID;
463 dev->mtu = 1500;
464 dev->tx_queue_len = 100;
465 dev->flags = IFF_NOARP;
466 dev->hard_header_len = LL_MAX_HEADER;
467 dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
468 }
469
470 static LIST_HEAD(master_dev_list);
471 static int max_equalizers = 1;
472 module_param(max_equalizers, int, 0);
473 MODULE_PARM_DESC(max_equalizers, "Max number of link equalizers");
474
475 static int __init teql_init(void)
476 {
477 int i;
478 int err = -ENODEV;
479
480 for (i = 0; i < max_equalizers; i++) {
481 struct net_device *dev;
482 struct teql_master *master;
483
484 dev = alloc_netdev(sizeof(struct teql_master),
485 "teql%d", teql_master_setup);
486 if (!dev) {
487 err = -ENOMEM;
488 break;
489 }
490
491 if ((err = register_netdev(dev))) {
492 free_netdev(dev);
493 break;
494 }
495
496 master = netdev_priv(dev);
497
498 strlcpy(master->qops.id, dev->name, IFNAMSIZ);
499 err = register_qdisc(&master->qops);
500
501 if (err) {
502 unregister_netdev(dev);
503 free_netdev(dev);
504 break;
505 }
506
507 list_add_tail(&master->master_list, &master_dev_list);
508 }
509 return i ? 0 : err;
510 }
511
512 static void __exit teql_exit(void)
513 {
514 struct teql_master *master, *nxt;
515
516 list_for_each_entry_safe(master, nxt, &master_dev_list, master_list) {
517
518 list_del(&master->master_list);
519
520 unregister_qdisc(&master->qops);
521 unregister_netdev(master->dev);
522 free_netdev(master->dev);
523 }
524 }
525
526 module_init(teql_init);
527 module_exit(teql_exit);
528
529 MODULE_LICENSE("GPL");
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