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net_sched: Add accessor function for packet length for qdiscs
[deliverable/linux.git] / net / sched / sch_teql.c
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)
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 = qdisc_dev(sch);
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 += qdisc_pkt_len(skb);
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 netdev_queue *dat_queue;
111 struct sk_buff *skb;
112
113 skb = __skb_dequeue(&dat->q);
114 dat_queue = netdev_get_tx_queue(dat->m->dev, 0);
115 if (skb == NULL) {
116 struct net_device *m = qdisc_dev(dat_queue->qdisc);
117 if (m) {
118 dat->m->slaves = sch;
119 netif_wake_queue(m);
120 }
121 }
122 sch->q.qlen = dat->q.qlen + dat_queue->qdisc->q.qlen;
123 return skb;
124 }
125
126 static __inline__ void
127 teql_neigh_release(struct neighbour *n)
128 {
129 if (n)
130 neigh_release(n);
131 }
132
133 static void
134 teql_reset(struct Qdisc* sch)
135 {
136 struct teql_sched_data *dat = qdisc_priv(sch);
137
138 skb_queue_purge(&dat->q);
139 sch->q.qlen = 0;
140 teql_neigh_release(xchg(&dat->ncache, NULL));
141 }
142
143 static void
144 teql_destroy(struct Qdisc* sch)
145 {
146 struct Qdisc *q, *prev;
147 struct teql_sched_data *dat = qdisc_priv(sch);
148 struct teql_master *master = dat->m;
149
150 if ((prev = master->slaves) != NULL) {
151 do {
152 q = NEXT_SLAVE(prev);
153 if (q == sch) {
154 NEXT_SLAVE(prev) = NEXT_SLAVE(q);
155 if (q == master->slaves) {
156 master->slaves = NEXT_SLAVE(q);
157 if (q == master->slaves) {
158 struct netdev_queue *txq;
159 spinlock_t *root_lock;
160
161 txq = netdev_get_tx_queue(master->dev, 0);
162 master->slaves = NULL;
163
164 root_lock = qdisc_root_lock(txq->qdisc);
165 spin_lock_bh(root_lock);
166 qdisc_reset(txq->qdisc);
167 spin_unlock_bh(root_lock);
168 }
169 }
170 skb_queue_purge(&dat->q);
171 teql_neigh_release(xchg(&dat->ncache, NULL));
172 break;
173 }
174
175 } while ((prev = q) != master->slaves);
176 }
177 }
178
179 static int teql_qdisc_init(struct Qdisc *sch, struct nlattr *opt)
180 {
181 struct net_device *dev = qdisc_dev(sch);
182 struct teql_master *m = (struct teql_master*)sch->ops;
183 struct teql_sched_data *q = qdisc_priv(sch);
184
185 if (dev->hard_header_len > m->dev->hard_header_len)
186 return -EINVAL;
187
188 if (m->dev == dev)
189 return -ELOOP;
190
191 q->m = m;
192
193 skb_queue_head_init(&q->q);
194
195 if (m->slaves) {
196 if (m->dev->flags & IFF_UP) {
197 if ((m->dev->flags&IFF_POINTOPOINT && !(dev->flags&IFF_POINTOPOINT))
198 || (m->dev->flags&IFF_BROADCAST && !(dev->flags&IFF_BROADCAST))
199 || (m->dev->flags&IFF_MULTICAST && !(dev->flags&IFF_MULTICAST))
200 || dev->mtu < m->dev->mtu)
201 return -EINVAL;
202 } else {
203 if (!(dev->flags&IFF_POINTOPOINT))
204 m->dev->flags &= ~IFF_POINTOPOINT;
205 if (!(dev->flags&IFF_BROADCAST))
206 m->dev->flags &= ~IFF_BROADCAST;
207 if (!(dev->flags&IFF_MULTICAST))
208 m->dev->flags &= ~IFF_MULTICAST;
209 if (dev->mtu < m->dev->mtu)
210 m->dev->mtu = dev->mtu;
211 }
212 q->next = NEXT_SLAVE(m->slaves);
213 NEXT_SLAVE(m->slaves) = sch;
214 } else {
215 q->next = sch;
216 m->slaves = sch;
217 m->dev->mtu = dev->mtu;
218 m->dev->flags = (m->dev->flags&~FMASK)|(dev->flags&FMASK);
219 }
220 return 0;
221 }
222
223
224 static int
225 __teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res, struct net_device *dev)
226 {
227 struct netdev_queue *dev_queue = netdev_get_tx_queue(dev, 0);
228 struct teql_sched_data *q = qdisc_priv(dev_queue->qdisc);
229 struct neighbour *mn = skb->dst->neighbour;
230 struct neighbour *n = q->ncache;
231
232 if (mn->tbl == NULL)
233 return -EINVAL;
234 if (n && n->tbl == mn->tbl &&
235 memcmp(n->primary_key, mn->primary_key, mn->tbl->key_len) == 0) {
236 atomic_inc(&n->refcnt);
237 } else {
238 n = __neigh_lookup_errno(mn->tbl, mn->primary_key, dev);
239 if (IS_ERR(n))
240 return PTR_ERR(n);
241 }
242 if (neigh_event_send(n, skb_res) == 0) {
243 int err;
244
245 read_lock(&n->lock);
246 err = dev_hard_header(skb, dev, ntohs(skb->protocol),
247 n->ha, NULL, skb->len);
248 read_unlock(&n->lock);
249
250 if (err < 0) {
251 neigh_release(n);
252 return -EINVAL;
253 }
254 teql_neigh_release(xchg(&q->ncache, n));
255 return 0;
256 }
257 neigh_release(n);
258 return (skb_res == NULL) ? -EAGAIN : 1;
259 }
260
261 static inline int teql_resolve(struct sk_buff *skb,
262 struct sk_buff *skb_res, struct net_device *dev)
263 {
264 struct netdev_queue *txq = netdev_get_tx_queue(dev, 0);
265 if (txq->qdisc == &noop_qdisc)
266 return -ENODEV;
267
268 if (dev->header_ops == 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 subq = skb_get_queue_mapping(skb);
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 = qdisc_dev(q);
295 struct netdev_queue *slave_txq;
296
297 slave_txq = netdev_get_tx_queue(slave, 0);
298 if (slave_txq->qdisc_sleeping != q)
299 continue;
300 if (__netif_subqueue_stopped(slave, subq) ||
301 !netif_running(slave)) {
302 busy = 1;
303 continue;
304 }
305
306 switch (teql_resolve(skb, skb_res, slave)) {
307 case 0:
308 if (netif_tx_trylock(slave)) {
309 if (!__netif_subqueue_stopped(slave, subq) &&
310 slave->hard_start_xmit(skb, slave) == 0) {
311 netif_tx_unlock(slave);
312 master->slaves = NEXT_SLAVE(q);
313 netif_wake_queue(dev);
314 master->stats.tx_packets++;
315 master->stats.tx_bytes +=
316 qdisc_pkt_len(skb);
317 return 0;
318 }
319 netif_tx_unlock(slave);
320 }
321 if (netif_queue_stopped(dev))
322 busy = 1;
323 break;
324 case 1:
325 master->slaves = NEXT_SLAVE(q);
326 return 0;
327 default:
328 nores = 1;
329 break;
330 }
331 __skb_pull(skb, skb_network_offset(skb));
332 } while ((q = NEXT_SLAVE(q)) != start);
333
334 if (nores && skb_res == NULL) {
335 skb_res = skb;
336 goto restart;
337 }
338
339 if (busy) {
340 netif_stop_queue(dev);
341 return 1;
342 }
343 master->stats.tx_errors++;
344
345 drop:
346 master->stats.tx_dropped++;
347 dev_kfree_skb(skb);
348 return 0;
349 }
350
351 static int teql_master_open(struct net_device *dev)
352 {
353 struct Qdisc * q;
354 struct teql_master *m = netdev_priv(dev);
355 int mtu = 0xFFFE;
356 unsigned flags = IFF_NOARP|IFF_MULTICAST;
357
358 if (m->slaves == NULL)
359 return -EUNATCH;
360
361 flags = FMASK;
362
363 q = m->slaves;
364 do {
365 struct net_device *slave = qdisc_dev(q);
366
367 if (slave == NULL)
368 return -EUNATCH;
369
370 if (slave->mtu < mtu)
371 mtu = slave->mtu;
372 if (slave->hard_header_len > LL_MAX_HEADER)
373 return -EINVAL;
374
375 /* If all the slaves are BROADCAST, master is BROADCAST
376 If all the slaves are PtP, master is PtP
377 Otherwise, master is NBMA.
378 */
379 if (!(slave->flags&IFF_POINTOPOINT))
380 flags &= ~IFF_POINTOPOINT;
381 if (!(slave->flags&IFF_BROADCAST))
382 flags &= ~IFF_BROADCAST;
383 if (!(slave->flags&IFF_MULTICAST))
384 flags &= ~IFF_MULTICAST;
385 } while ((q = NEXT_SLAVE(q)) != m->slaves);
386
387 m->dev->mtu = mtu;
388 m->dev->flags = (m->dev->flags&~FMASK) | flags;
389 netif_start_queue(m->dev);
390 return 0;
391 }
392
393 static int teql_master_close(struct net_device *dev)
394 {
395 netif_stop_queue(dev);
396 return 0;
397 }
398
399 static struct net_device_stats *teql_master_stats(struct net_device *dev)
400 {
401 struct teql_master *m = netdev_priv(dev);
402 return &m->stats;
403 }
404
405 static int teql_master_mtu(struct net_device *dev, int new_mtu)
406 {
407 struct teql_master *m = netdev_priv(dev);
408 struct Qdisc *q;
409
410 if (new_mtu < 68)
411 return -EINVAL;
412
413 q = m->slaves;
414 if (q) {
415 do {
416 if (new_mtu > qdisc_dev(q)->mtu)
417 return -EINVAL;
418 } while ((q=NEXT_SLAVE(q)) != m->slaves);
419 }
420
421 dev->mtu = new_mtu;
422 return 0;
423 }
424
425 static __init void teql_master_setup(struct net_device *dev)
426 {
427 struct teql_master *master = netdev_priv(dev);
428 struct Qdisc_ops *ops = &master->qops;
429
430 master->dev = dev;
431 ops->priv_size = sizeof(struct teql_sched_data);
432
433 ops->enqueue = teql_enqueue;
434 ops->dequeue = teql_dequeue;
435 ops->requeue = teql_requeue;
436 ops->init = teql_qdisc_init;
437 ops->reset = teql_reset;
438 ops->destroy = teql_destroy;
439 ops->owner = THIS_MODULE;
440
441 dev->open = teql_master_open;
442 dev->hard_start_xmit = teql_master_xmit;
443 dev->stop = teql_master_close;
444 dev->get_stats = teql_master_stats;
445 dev->change_mtu = teql_master_mtu;
446 dev->type = ARPHRD_VOID;
447 dev->mtu = 1500;
448 dev->tx_queue_len = 100;
449 dev->flags = IFF_NOARP;
450 dev->hard_header_len = LL_MAX_HEADER;
451 }
452
453 static LIST_HEAD(master_dev_list);
454 static int max_equalizers = 1;
455 module_param(max_equalizers, int, 0);
456 MODULE_PARM_DESC(max_equalizers, "Max number of link equalizers");
457
458 static int __init teql_init(void)
459 {
460 int i;
461 int err = -ENODEV;
462
463 for (i = 0; i < max_equalizers; i++) {
464 struct net_device *dev;
465 struct teql_master *master;
466
467 dev = alloc_netdev(sizeof(struct teql_master),
468 "teql%d", teql_master_setup);
469 if (!dev) {
470 err = -ENOMEM;
471 break;
472 }
473
474 if ((err = register_netdev(dev))) {
475 free_netdev(dev);
476 break;
477 }
478
479 master = netdev_priv(dev);
480
481 strlcpy(master->qops.id, dev->name, IFNAMSIZ);
482 err = register_qdisc(&master->qops);
483
484 if (err) {
485 unregister_netdev(dev);
486 free_netdev(dev);
487 break;
488 }
489
490 list_add_tail(&master->master_list, &master_dev_list);
491 }
492 return i ? 0 : err;
493 }
494
495 static void __exit teql_exit(void)
496 {
497 struct teql_master *master, *nxt;
498
499 list_for_each_entry_safe(master, nxt, &master_dev_list, master_list) {
500
501 list_del(&master->master_list);
502
503 unregister_qdisc(&master->qops);
504 unregister_netdev(master->dev);
505 free_netdev(master->dev);
506 }
507 }
508
509 module_init(teql_init);
510 module_exit(teql_exit);
511
512 MODULE_LICENSE("GPL");
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