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cciss: reformat error handling
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / net / sched / sch_teql.c
blobd24914db786124d187fc53a546d2ab9c5ebac958
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 __skb_queue_tail(&q->q, skb);
98 if (q->q.qlen <= dev->tx_queue_len) {
99 sch->bstats.bytes += skb->len;
100 sch->bstats.packets++;
101 return 0;
102 }
103
104 __skb_unlink(skb, &q->q);
105 kfree_skb(skb);
106 sch->qstats.drops++;
107 return NET_XMIT_DROP;
108 }
109
110 static int
111 teql_requeue(struct sk_buff *skb, struct Qdisc* sch)
112 {
113 struct teql_sched_data *q = qdisc_priv(sch);
114
115 __skb_queue_head(&q->q, skb);
116 sch->qstats.requeues++;
117 return 0;
118 }
119
120 static struct sk_buff *
121 teql_dequeue(struct Qdisc* sch)
122 {
123 struct teql_sched_data *dat = qdisc_priv(sch);
124 struct sk_buff *skb;
125
126 skb = __skb_dequeue(&dat->q);
127 if (skb == NULL) {
128 struct net_device *m = dat->m->dev->qdisc->dev;
129 if (m) {
130 dat->m->slaves = sch;
131 netif_wake_queue(m);
132 }
133 }
134 sch->q.qlen = dat->q.qlen + dat->m->dev->qdisc->q.qlen;
135 return skb;
136 }
137
138 static __inline__ void
139 teql_neigh_release(struct neighbour *n)
140 {
141 if (n)
142 neigh_release(n);
143 }
144
145 static void
146 teql_reset(struct Qdisc* sch)
147 {
148 struct teql_sched_data *dat = qdisc_priv(sch);
149
150 skb_queue_purge(&dat->q);
151 sch->q.qlen = 0;
152 teql_neigh_release(xchg(&dat->ncache, NULL));
153 }
154
155 static void
156 teql_destroy(struct Qdisc* sch)
157 {
158 struct Qdisc *q, *prev;
159 struct teql_sched_data *dat = qdisc_priv(sch);
160 struct teql_master *master = dat->m;
161
162 if ((prev = master->slaves) != NULL) {
163 do {
164 q = NEXT_SLAVE(prev);
165 if (q == sch) {
166 NEXT_SLAVE(prev) = NEXT_SLAVE(q);
167 if (q == master->slaves) {
168 master->slaves = NEXT_SLAVE(q);
169 if (q == master->slaves) {
170 master->slaves = NULL;
171 spin_lock_bh(&master->dev->queue_lock);
172 qdisc_reset(master->dev->qdisc);
173 spin_unlock_bh(&master->dev->queue_lock);
174 }
175 }
176 skb_queue_purge(&dat->q);
177 teql_neigh_release(xchg(&dat->ncache, NULL));
178 break;
179 }
180
181 } while ((prev = q) != master->slaves);
182 }
183 }
184
185 static int teql_qdisc_init(struct Qdisc *sch, struct rtattr *opt)
186 {
187 struct net_device *dev = sch->dev;
188 struct teql_master *m = (struct teql_master*)sch->ops;
189 struct teql_sched_data *q = qdisc_priv(sch);
190
191 if (dev->hard_header_len > m->dev->hard_header_len)
192 return -EINVAL;
193
194 if (m->dev == dev)
195 return -ELOOP;
196
197 q->m = m;
198
199 skb_queue_head_init(&q->q);
200
201 if (m->slaves) {
202 if (m->dev->flags & IFF_UP) {
203 if ((m->dev->flags&IFF_POINTOPOINT && !(dev->flags&IFF_POINTOPOINT))
204 || (m->dev->flags&IFF_BROADCAST && !(dev->flags&IFF_BROADCAST))
205 || (m->dev->flags&IFF_MULTICAST && !(dev->flags&IFF_MULTICAST))
206 || dev->mtu < m->dev->mtu)
207 return -EINVAL;
208 } else {
209 if (!(dev->flags&IFF_POINTOPOINT))
210 m->dev->flags &= ~IFF_POINTOPOINT;
211 if (!(dev->flags&IFF_BROADCAST))
212 m->dev->flags &= ~IFF_BROADCAST;
213 if (!(dev->flags&IFF_MULTICAST))
214 m->dev->flags &= ~IFF_MULTICAST;
215 if (dev->mtu < m->dev->mtu)
216 m->dev->mtu = dev->mtu;
217 }
218 q->next = NEXT_SLAVE(m->slaves);
219 NEXT_SLAVE(m->slaves) = sch;
220 } else {
221 q->next = sch;
222 m->slaves = sch;
223 m->dev->mtu = dev->mtu;
224 m->dev->flags = (m->dev->flags&~FMASK)|(dev->flags&FMASK);
225 }
226 return 0;
227 }
228
229 /* "teql*" netdevice routines */
230
231 static int
232 __teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res, struct net_device *dev)
233 {
234 struct teql_sched_data *q = qdisc_priv(dev->qdisc);
235 struct neighbour *mn = skb->dst->neighbour;
236 struct neighbour *n = q->ncache;
237
238 if (mn->tbl == NULL)
239 return -EINVAL;
240 if (n && n->tbl == mn->tbl &&
241 memcmp(n->primary_key, mn->primary_key, mn->tbl->key_len) == 0) {
242 atomic_inc(&n->refcnt);
243 } else {
244 n = __neigh_lookup_errno(mn->tbl, mn->primary_key, dev);
245 if (IS_ERR(n))
246 return PTR_ERR(n);
247 }
248 if (neigh_event_send(n, skb_res) == 0) {
249 int err;
250 read_lock(&n->lock);
251 err = dev->hard_header(skb, dev, ntohs(skb->protocol), n->ha, NULL, skb->len);
252 read_unlock(&n->lock);
253 if (err < 0) {
254 neigh_release(n);
255 return -EINVAL;
256 }
257 teql_neigh_release(xchg(&q->ncache, n));
258 return 0;
259 }
260 neigh_release(n);
261 return (skb_res == NULL) ? -EAGAIN : 1;
262 }
263
264 static __inline__ int
265 teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res, struct net_device *dev)
266 {
267 if (dev->hard_header == NULL ||
268 skb->dst == NULL ||
269 skb->dst->neighbour == NULL)
270 return 0;
271 return __teql_resolve(skb, skb_res, dev);
272 }
273
274 static int teql_master_xmit(struct sk_buff *skb, struct net_device *dev)
275 {
276 struct teql_master *master = netdev_priv(dev);
277 struct Qdisc *start, *q;
278 int busy;
279 int nores;
280 int len = skb->len;
281 struct sk_buff *skb_res = NULL;
282
283 start = master->slaves;
284
285 restart:
286 nores = 0;
287 busy = 0;
288
289 if ((q = start) == NULL)
290 goto drop;
291
292 do {
293 struct net_device *slave = q->dev;
294
295 if (slave->qdisc_sleeping != q)
296 continue;
297 if (netif_queue_stopped(slave) || ! netif_running(slave)) {
298 busy = 1;
299 continue;
300 }
301
302 switch (teql_resolve(skb, skb_res, slave)) {
303 case 0:
304 if (netif_tx_trylock(slave)) {
305 if (!netif_queue_stopped(slave) &&
306 slave->hard_start_xmit(skb, slave) == 0) {
307 netif_tx_unlock(slave);
308 master->slaves = NEXT_SLAVE(q);
309 netif_wake_queue(dev);
310 master->stats.tx_packets++;
311 master->stats.tx_bytes += len;
312 return 0;
313 }
314 netif_tx_unlock(slave);
315 }
316 if (netif_queue_stopped(dev))
317 busy = 1;
318 break;
319 case 1:
320 master->slaves = NEXT_SLAVE(q);
321 return 0;
322 default:
323 nores = 1;
324 break;
325 }
326 __skb_pull(skb, skb_network_offset(skb));
327 } while ((q = NEXT_SLAVE(q)) != start);
328
329 if (nores && skb_res == NULL) {
330 skb_res = skb;
331 goto restart;
332 }
333
334 if (busy) {
335 netif_stop_queue(dev);
336 return 1;
337 }
338 master->stats.tx_errors++;
339
340 drop:
341 master->stats.tx_dropped++;
342 dev_kfree_skb(skb);
343 return 0;
344 }
345
346 static int teql_master_open(struct net_device *dev)
347 {
348 struct Qdisc * q;
349 struct teql_master *m = netdev_priv(dev);
350 int mtu = 0xFFFE;
351 unsigned flags = IFF_NOARP|IFF_MULTICAST;
352
353 if (m->slaves == NULL)
354 return -EUNATCH;
355
356 flags = FMASK;
357
358 q = m->slaves;
359 do {
360 struct net_device *slave = q->dev;
361
362 if (slave == NULL)
363 return -EUNATCH;
364
365 if (slave->mtu < mtu)
366 mtu = slave->mtu;
367 if (slave->hard_header_len > LL_MAX_HEADER)
368 return -EINVAL;
369
370 /* If all the slaves are BROADCAST, master is BROADCAST
371 If all the slaves are PtP, master is PtP
372 Otherwise, master is NBMA.
373 */
374 if (!(slave->flags&IFF_POINTOPOINT))
375 flags &= ~IFF_POINTOPOINT;
376 if (!(slave->flags&IFF_BROADCAST))
377 flags &= ~IFF_BROADCAST;
378 if (!(slave->flags&IFF_MULTICAST))
379 flags &= ~IFF_MULTICAST;
380 } while ((q = NEXT_SLAVE(q)) != m->slaves);
381
382 m->dev->mtu = mtu;
383 m->dev->flags = (m->dev->flags&~FMASK) | flags;
384 netif_start_queue(m->dev);
385 return 0;
386 }
387
388 static int teql_master_close(struct net_device *dev)
389 {
390 netif_stop_queue(dev);
391 return 0;
392 }
393
394 static struct net_device_stats *teql_master_stats(struct net_device *dev)
395 {
396 struct teql_master *m = netdev_priv(dev);
397 return &m->stats;
398 }
399
400 static int teql_master_mtu(struct net_device *dev, int new_mtu)
401 {
402 struct teql_master *m = netdev_priv(dev);
403 struct Qdisc *q;
404
405 if (new_mtu < 68)
406 return -EINVAL;
407
408 q = m->slaves;
409 if (q) {
410 do {
411 if (new_mtu > q->dev->mtu)
412 return -EINVAL;
413 } while ((q=NEXT_SLAVE(q)) != m->slaves);
414 }
415
416 dev->mtu = new_mtu;
417 return 0;
418 }
419
420 static __init void teql_master_setup(struct net_device *dev)
421 {
422 struct teql_master *master = netdev_priv(dev);
423 struct Qdisc_ops *ops = &master->qops;
424
425 master->dev = dev;
426 ops->priv_size = sizeof(struct teql_sched_data);
427
428 ops->enqueue = teql_enqueue;
429 ops->dequeue = teql_dequeue;
430 ops->requeue = teql_requeue;
431 ops->init = teql_qdisc_init;
432 ops->reset = teql_reset;
433 ops->destroy = teql_destroy;
434 ops->owner = THIS_MODULE;
435
436 dev->open = teql_master_open;
437 dev->hard_start_xmit = teql_master_xmit;
438 dev->stop = teql_master_close;
439 dev->get_stats = teql_master_stats;
440 dev->change_mtu = teql_master_mtu;
441 dev->type = ARPHRD_VOID;
442 dev->mtu = 1500;
443 dev->tx_queue_len = 100;
444 dev->flags = IFF_NOARP;
445 dev->hard_header_len = LL_MAX_HEADER;
446 SET_MODULE_OWNER(dev);
447 }
448
449 static LIST_HEAD(master_dev_list);
450 static int max_equalizers = 1;
451 module_param(max_equalizers, int, 0);
452 MODULE_PARM_DESC(max_equalizers, "Max number of link equalizers");
453
454 static int __init teql_init(void)
455 {
456 int i;
457 int err = -ENODEV;
458
459 for (i = 0; i < max_equalizers; i++) {
460 struct net_device *dev;
461 struct teql_master *master;
462
463 dev = alloc_netdev(sizeof(struct teql_master),
464 "teql%d", teql_master_setup);
465 if (!dev) {
466 err = -ENOMEM;
467 break;
468 }
469
470 if ((err = register_netdev(dev))) {
471 free_netdev(dev);
472 break;
473 }
474
475 master = netdev_priv(dev);
476
477 strlcpy(master->qops.id, dev->name, IFNAMSIZ);
478 err = register_qdisc(&master->qops);
479
480 if (err) {
481 unregister_netdev(dev);
482 free_netdev(dev);
483 break;
484 }
485
486 list_add_tail(&master->master_list, &master_dev_list);
487 }
488 return i ? 0 : err;
489 }
490
491 static void __exit teql_exit(void)
492 {
493 struct teql_master *master, *nxt;
494
495 list_for_each_entry_safe(master, nxt, &master_dev_list, master_list) {
496
497 list_del(&master->master_list);
498
499 unregister_qdisc(&master->qops);
500 unregister_netdev(master->dev);
501 free_netdev(master->dev);
502 }
503 }
504
505 module_init(teql_init);
506 module_exit(teql_exit);
507
508 MODULE_LICENSE("GPL");
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