Commit | Line | Data |
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1da177e4 LT |
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> | |
1da177e4 LT |
12 | #include <linux/types.h> |
13 | #include <linux/kernel.h> | |
1da177e4 | 14 | #include <linux/string.h> |
1da177e4 | 15 | #include <linux/errno.h> |
14c85021 | 16 | #include <linux/if_arp.h> |
1da177e4 | 17 | #include <linux/netdevice.h> |
1da177e4 | 18 | #include <linux/init.h> |
1da177e4 LT |
19 | #include <linux/skbuff.h> |
20 | #include <linux/moduleparam.h> | |
0ba48053 PM |
21 | #include <net/dst.h> |
22 | #include <net/neighbour.h> | |
1da177e4 LT |
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 | ||
cc8fd14d | 74 | #define FMASK (IFF_BROADCAST|IFF_POINTOPOINT) |
1da177e4 LT |
75 | |
76 | /* "teql*" qdisc routines */ | |
77 | ||
78 | static int | |
79 | teql_enqueue(struct sk_buff *skb, struct Qdisc* sch) | |
80 | { | |
5ce2d488 | 81 | struct net_device *dev = qdisc_dev(sch); |
1da177e4 LT |
82 | struct teql_sched_data *q = qdisc_priv(sch); |
83 | ||
4cd8c9e8 KK |
84 | if (q->q.qlen < dev->tx_queue_len) { |
85 | __skb_queue_tail(&q->q, skb); | |
0abf77e5 | 86 | sch->bstats.bytes += qdisc_pkt_len(skb); |
1da177e4 LT |
87 | sch->bstats.packets++; |
88 | return 0; | |
89 | } | |
90 | ||
1da177e4 LT |
91 | kfree_skb(skb); |
92 | sch->qstats.drops++; | |
93 | return NET_XMIT_DROP; | |
94 | } | |
95 | ||
1da177e4 LT |
96 | static struct sk_buff * |
97 | teql_dequeue(struct Qdisc* sch) | |
98 | { | |
99 | struct teql_sched_data *dat = qdisc_priv(sch); | |
b0e1e646 | 100 | struct netdev_queue *dat_queue; |
1da177e4 LT |
101 | struct sk_buff *skb; |
102 | ||
103 | skb = __skb_dequeue(&dat->q); | |
e8a0464c | 104 | dat_queue = netdev_get_tx_queue(dat->m->dev, 0); |
1da177e4 | 105 | if (skb == NULL) { |
b0e1e646 | 106 | struct net_device *m = qdisc_dev(dat_queue->qdisc); |
1da177e4 LT |
107 | if (m) { |
108 | dat->m->slaves = sch; | |
109 | netif_wake_queue(m); | |
110 | } | |
111 | } | |
b0e1e646 | 112 | sch->q.qlen = dat->q.qlen + dat_queue->qdisc->q.qlen; |
1da177e4 LT |
113 | return skb; |
114 | } | |
115 | ||
8e3af978 JP |
116 | static struct sk_buff * |
117 | teql_peek(struct Qdisc* sch) | |
118 | { | |
119 | /* teql is meant to be used as root qdisc */ | |
120 | return NULL; | |
121 | } | |
122 | ||
1da177e4 LT |
123 | static __inline__ void |
124 | teql_neigh_release(struct neighbour *n) | |
125 | { | |
126 | if (n) | |
127 | neigh_release(n); | |
128 | } | |
129 | ||
130 | static void | |
131 | teql_reset(struct Qdisc* sch) | |
132 | { | |
133 | struct teql_sched_data *dat = qdisc_priv(sch); | |
134 | ||
135 | skb_queue_purge(&dat->q); | |
136 | sch->q.qlen = 0; | |
137 | teql_neigh_release(xchg(&dat->ncache, NULL)); | |
138 | } | |
139 | ||
140 | static void | |
141 | teql_destroy(struct Qdisc* sch) | |
142 | { | |
143 | struct Qdisc *q, *prev; | |
144 | struct teql_sched_data *dat = qdisc_priv(sch); | |
145 | struct teql_master *master = dat->m; | |
146 | ||
147 | if ((prev = master->slaves) != NULL) { | |
148 | do { | |
149 | q = NEXT_SLAVE(prev); | |
150 | if (q == sch) { | |
151 | NEXT_SLAVE(prev) = NEXT_SLAVE(q); | |
152 | if (q == master->slaves) { | |
153 | master->slaves = NEXT_SLAVE(q); | |
154 | if (q == master->slaves) { | |
e8a0464c | 155 | struct netdev_queue *txq; |
83874000 | 156 | spinlock_t *root_lock; |
e8a0464c DM |
157 | |
158 | txq = netdev_get_tx_queue(master->dev, 0); | |
1da177e4 | 159 | master->slaves = NULL; |
83874000 | 160 | |
102396ae | 161 | root_lock = qdisc_root_sleeping_lock(txq->qdisc); |
83874000 | 162 | spin_lock_bh(root_lock); |
e8a0464c | 163 | qdisc_reset(txq->qdisc); |
83874000 | 164 | spin_unlock_bh(root_lock); |
1da177e4 LT |
165 | } |
166 | } | |
167 | skb_queue_purge(&dat->q); | |
168 | teql_neigh_release(xchg(&dat->ncache, NULL)); | |
169 | break; | |
170 | } | |
10297b99 | 171 | |
1da177e4 LT |
172 | } while ((prev = q) != master->slaves); |
173 | } | |
174 | } | |
175 | ||
1e90474c | 176 | static int teql_qdisc_init(struct Qdisc *sch, struct nlattr *opt) |
1da177e4 | 177 | { |
5ce2d488 | 178 | struct net_device *dev = qdisc_dev(sch); |
1da177e4 LT |
179 | struct teql_master *m = (struct teql_master*)sch->ops; |
180 | struct teql_sched_data *q = qdisc_priv(sch); | |
181 | ||
182 | if (dev->hard_header_len > m->dev->hard_header_len) | |
183 | return -EINVAL; | |
184 | ||
185 | if (m->dev == dev) | |
186 | return -ELOOP; | |
187 | ||
188 | q->m = m; | |
189 | ||
190 | skb_queue_head_init(&q->q); | |
191 | ||
192 | if (m->slaves) { | |
193 | if (m->dev->flags & IFF_UP) { | |
194 | if ((m->dev->flags&IFF_POINTOPOINT && !(dev->flags&IFF_POINTOPOINT)) | |
195 | || (m->dev->flags&IFF_BROADCAST && !(dev->flags&IFF_BROADCAST)) | |
196 | || (m->dev->flags&IFF_MULTICAST && !(dev->flags&IFF_MULTICAST)) | |
197 | || dev->mtu < m->dev->mtu) | |
198 | return -EINVAL; | |
199 | } else { | |
200 | if (!(dev->flags&IFF_POINTOPOINT)) | |
201 | m->dev->flags &= ~IFF_POINTOPOINT; | |
202 | if (!(dev->flags&IFF_BROADCAST)) | |
203 | m->dev->flags &= ~IFF_BROADCAST; | |
204 | if (!(dev->flags&IFF_MULTICAST)) | |
205 | m->dev->flags &= ~IFF_MULTICAST; | |
206 | if (dev->mtu < m->dev->mtu) | |
207 | m->dev->mtu = dev->mtu; | |
208 | } | |
209 | q->next = NEXT_SLAVE(m->slaves); | |
210 | NEXT_SLAVE(m->slaves) = sch; | |
211 | } else { | |
212 | q->next = sch; | |
213 | m->slaves = sch; | |
214 | m->dev->mtu = dev->mtu; | |
215 | m->dev->flags = (m->dev->flags&~FMASK)|(dev->flags&FMASK); | |
216 | } | |
217 | return 0; | |
218 | } | |
219 | ||
1da177e4 LT |
220 | |
221 | static int | |
222 | __teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res, struct net_device *dev) | |
223 | { | |
e8a0464c DM |
224 | struct netdev_queue *dev_queue = netdev_get_tx_queue(dev, 0); |
225 | struct teql_sched_data *q = qdisc_priv(dev_queue->qdisc); | |
1da177e4 LT |
226 | struct neighbour *mn = skb->dst->neighbour; |
227 | struct neighbour *n = q->ncache; | |
228 | ||
229 | if (mn->tbl == NULL) | |
230 | return -EINVAL; | |
231 | if (n && n->tbl == mn->tbl && | |
232 | memcmp(n->primary_key, mn->primary_key, mn->tbl->key_len) == 0) { | |
233 | atomic_inc(&n->refcnt); | |
234 | } else { | |
235 | n = __neigh_lookup_errno(mn->tbl, mn->primary_key, dev); | |
236 | if (IS_ERR(n)) | |
237 | return PTR_ERR(n); | |
238 | } | |
239 | if (neigh_event_send(n, skb_res) == 0) { | |
240 | int err; | |
0c4e8581 | 241 | |
1da177e4 | 242 | read_lock(&n->lock); |
0c4e8581 SH |
243 | err = dev_hard_header(skb, dev, ntohs(skb->protocol), |
244 | n->ha, NULL, skb->len); | |
1da177e4 | 245 | read_unlock(&n->lock); |
0c4e8581 | 246 | |
1da177e4 LT |
247 | if (err < 0) { |
248 | neigh_release(n); | |
249 | return -EINVAL; | |
250 | } | |
251 | teql_neigh_release(xchg(&q->ncache, n)); | |
252 | return 0; | |
253 | } | |
254 | neigh_release(n); | |
255 | return (skb_res == NULL) ? -EAGAIN : 1; | |
256 | } | |
257 | ||
3b04ddde SH |
258 | static inline int teql_resolve(struct sk_buff *skb, |
259 | struct sk_buff *skb_res, struct net_device *dev) | |
1da177e4 | 260 | { |
e8a0464c DM |
261 | struct netdev_queue *txq = netdev_get_tx_queue(dev, 0); |
262 | if (txq->qdisc == &noop_qdisc) | |
4f9f8311 EP |
263 | return -ENODEV; |
264 | ||
3b04ddde | 265 | if (dev->header_ops == NULL || |
1da177e4 LT |
266 | skb->dst == NULL || |
267 | skb->dst->neighbour == NULL) | |
268 | return 0; | |
269 | return __teql_resolve(skb, skb_res, dev); | |
270 | } | |
271 | ||
272 | static int teql_master_xmit(struct sk_buff *skb, struct net_device *dev) | |
273 | { | |
2941a486 | 274 | struct teql_master *master = netdev_priv(dev); |
1da177e4 LT |
275 | struct Qdisc *start, *q; |
276 | int busy; | |
277 | int nores; | |
4e3ab47a | 278 | int subq = skb_get_queue_mapping(skb); |
1da177e4 LT |
279 | struct sk_buff *skb_res = NULL; |
280 | ||
281 | start = master->slaves; | |
282 | ||
283 | restart: | |
284 | nores = 0; | |
285 | busy = 0; | |
286 | ||
287 | if ((q = start) == NULL) | |
288 | goto drop; | |
289 | ||
290 | do { | |
5ce2d488 | 291 | struct net_device *slave = qdisc_dev(q); |
61294e2e SH |
292 | struct netdev_queue *slave_txq = netdev_get_tx_queue(slave, 0); |
293 | const struct net_device_ops *slave_ops = slave->netdev_ops; | |
10297b99 | 294 | |
e8a0464c | 295 | if (slave_txq->qdisc_sleeping != q) |
1da177e4 | 296 | continue; |
fd2ea0a7 | 297 | if (__netif_subqueue_stopped(slave, subq) || |
f25f4e44 | 298 | !netif_running(slave)) { |
1da177e4 LT |
299 | busy = 1; |
300 | continue; | |
301 | } | |
302 | ||
303 | switch (teql_resolve(skb, skb_res, slave)) { | |
304 | case 0: | |
c3f26a26 DM |
305 | if (__netif_tx_trylock(slave_txq)) { |
306 | if (!netif_tx_queue_stopped(slave_txq) && | |
307 | !netif_tx_queue_frozen(slave_txq) && | |
61294e2e | 308 | slave_ops->ndo_start_xmit(skb, slave) == 0) { |
c3f26a26 | 309 | __netif_tx_unlock(slave_txq); |
1da177e4 LT |
310 | master->slaves = NEXT_SLAVE(q); |
311 | netif_wake_queue(dev); | |
312 | master->stats.tx_packets++; | |
0abf77e5 JK |
313 | master->stats.tx_bytes += |
314 | qdisc_pkt_len(skb); | |
1da177e4 LT |
315 | return 0; |
316 | } | |
c3f26a26 | 317 | __netif_tx_unlock(slave_txq); |
1da177e4 LT |
318 | } |
319 | if (netif_queue_stopped(dev)) | |
320 | busy = 1; | |
321 | break; | |
322 | case 1: | |
323 | master->slaves = NEXT_SLAVE(q); | |
324 | return 0; | |
325 | default: | |
326 | nores = 1; | |
327 | break; | |
328 | } | |
bbe735e4 | 329 | __skb_pull(skb, skb_network_offset(skb)); |
1da177e4 LT |
330 | } while ((q = NEXT_SLAVE(q)) != start); |
331 | ||
332 | if (nores && skb_res == NULL) { | |
333 | skb_res = skb; | |
334 | goto restart; | |
335 | } | |
336 | ||
337 | if (busy) { | |
338 | netif_stop_queue(dev); | |
339 | return 1; | |
340 | } | |
341 | master->stats.tx_errors++; | |
342 | ||
343 | drop: | |
344 | master->stats.tx_dropped++; | |
345 | dev_kfree_skb(skb); | |
346 | return 0; | |
347 | } | |
348 | ||
349 | static int teql_master_open(struct net_device *dev) | |
350 | { | |
351 | struct Qdisc * q; | |
2941a486 | 352 | struct teql_master *m = netdev_priv(dev); |
1da177e4 LT |
353 | int mtu = 0xFFFE; |
354 | unsigned flags = IFF_NOARP|IFF_MULTICAST; | |
355 | ||
356 | if (m->slaves == NULL) | |
357 | return -EUNATCH; | |
358 | ||
359 | flags = FMASK; | |
360 | ||
361 | q = m->slaves; | |
362 | do { | |
5ce2d488 | 363 | struct net_device *slave = qdisc_dev(q); |
1da177e4 LT |
364 | |
365 | if (slave == NULL) | |
366 | return -EUNATCH; | |
367 | ||
368 | if (slave->mtu < mtu) | |
369 | mtu = slave->mtu; | |
370 | if (slave->hard_header_len > LL_MAX_HEADER) | |
371 | return -EINVAL; | |
372 | ||
373 | /* If all the slaves are BROADCAST, master is BROADCAST | |
374 | If all the slaves are PtP, master is PtP | |
375 | Otherwise, master is NBMA. | |
376 | */ | |
377 | if (!(slave->flags&IFF_POINTOPOINT)) | |
378 | flags &= ~IFF_POINTOPOINT; | |
379 | if (!(slave->flags&IFF_BROADCAST)) | |
380 | flags &= ~IFF_BROADCAST; | |
381 | if (!(slave->flags&IFF_MULTICAST)) | |
382 | flags &= ~IFF_MULTICAST; | |
383 | } while ((q = NEXT_SLAVE(q)) != m->slaves); | |
384 | ||
385 | m->dev->mtu = mtu; | |
386 | m->dev->flags = (m->dev->flags&~FMASK) | flags; | |
387 | netif_start_queue(m->dev); | |
388 | return 0; | |
389 | } | |
390 | ||
391 | static int teql_master_close(struct net_device *dev) | |
392 | { | |
393 | netif_stop_queue(dev); | |
394 | return 0; | |
395 | } | |
396 | ||
397 | static struct net_device_stats *teql_master_stats(struct net_device *dev) | |
398 | { | |
2941a486 | 399 | struct teql_master *m = netdev_priv(dev); |
1da177e4 LT |
400 | return &m->stats; |
401 | } | |
402 | ||
403 | static int teql_master_mtu(struct net_device *dev, int new_mtu) | |
404 | { | |
2941a486 | 405 | struct teql_master *m = netdev_priv(dev); |
1da177e4 LT |
406 | struct Qdisc *q; |
407 | ||
408 | if (new_mtu < 68) | |
409 | return -EINVAL; | |
410 | ||
411 | q = m->slaves; | |
412 | if (q) { | |
413 | do { | |
5ce2d488 | 414 | if (new_mtu > qdisc_dev(q)->mtu) |
1da177e4 LT |
415 | return -EINVAL; |
416 | } while ((q=NEXT_SLAVE(q)) != m->slaves); | |
417 | } | |
418 | ||
419 | dev->mtu = new_mtu; | |
420 | return 0; | |
421 | } | |
422 | ||
61294e2e SH |
423 | static const struct net_device_ops teql_netdev_ops = { |
424 | .ndo_open = teql_master_open, | |
425 | .ndo_stop = teql_master_close, | |
426 | .ndo_start_xmit = teql_master_xmit, | |
427 | .ndo_get_stats = teql_master_stats, | |
428 | .ndo_change_mtu = teql_master_mtu, | |
429 | }; | |
430 | ||
1da177e4 LT |
431 | static __init void teql_master_setup(struct net_device *dev) |
432 | { | |
2941a486 | 433 | struct teql_master *master = netdev_priv(dev); |
1da177e4 LT |
434 | struct Qdisc_ops *ops = &master->qops; |
435 | ||
436 | master->dev = dev; | |
437 | ops->priv_size = sizeof(struct teql_sched_data); | |
10297b99 | 438 | |
1da177e4 LT |
439 | ops->enqueue = teql_enqueue; |
440 | ops->dequeue = teql_dequeue; | |
8e3af978 | 441 | ops->peek = teql_peek; |
1da177e4 LT |
442 | ops->init = teql_qdisc_init; |
443 | ops->reset = teql_reset; | |
444 | ops->destroy = teql_destroy; | |
445 | ops->owner = THIS_MODULE; | |
446 | ||
61294e2e | 447 | dev->netdev_ops = &teql_netdev_ops; |
1da177e4 LT |
448 | dev->type = ARPHRD_VOID; |
449 | dev->mtu = 1500; | |
450 | dev->tx_queue_len = 100; | |
451 | dev->flags = IFF_NOARP; | |
452 | dev->hard_header_len = LL_MAX_HEADER; | |
1da177e4 LT |
453 | } |
454 | ||
455 | static LIST_HEAD(master_dev_list); | |
456 | static int max_equalizers = 1; | |
457 | module_param(max_equalizers, int, 0); | |
458 | MODULE_PARM_DESC(max_equalizers, "Max number of link equalizers"); | |
459 | ||
460 | static int __init teql_init(void) | |
461 | { | |
462 | int i; | |
463 | int err = -ENODEV; | |
464 | ||
465 | for (i = 0; i < max_equalizers; i++) { | |
466 | struct net_device *dev; | |
467 | struct teql_master *master; | |
468 | ||
469 | dev = alloc_netdev(sizeof(struct teql_master), | |
470 | "teql%d", teql_master_setup); | |
471 | if (!dev) { | |
472 | err = -ENOMEM; | |
473 | break; | |
474 | } | |
475 | ||
476 | if ((err = register_netdev(dev))) { | |
477 | free_netdev(dev); | |
478 | break; | |
479 | } | |
480 | ||
2941a486 | 481 | master = netdev_priv(dev); |
1da177e4 LT |
482 | |
483 | strlcpy(master->qops.id, dev->name, IFNAMSIZ); | |
484 | err = register_qdisc(&master->qops); | |
485 | ||
486 | if (err) { | |
487 | unregister_netdev(dev); | |
488 | free_netdev(dev); | |
489 | break; | |
490 | } | |
491 | ||
492 | list_add_tail(&master->master_list, &master_dev_list); | |
493 | } | |
494 | return i ? 0 : err; | |
495 | } | |
496 | ||
10297b99 | 497 | static void __exit teql_exit(void) |
1da177e4 LT |
498 | { |
499 | struct teql_master *master, *nxt; | |
500 | ||
501 | list_for_each_entry_safe(master, nxt, &master_dev_list, master_list) { | |
502 | ||
503 | list_del(&master->master_list); | |
504 | ||
505 | unregister_qdisc(&master->qops); | |
506 | unregister_netdev(master->dev); | |
507 | free_netdev(master->dev); | |
508 | } | |
509 | } | |
510 | ||
511 | module_init(teql_init); | |
512 | module_exit(teql_exit); | |
513 | ||
514 | MODULE_LICENSE("GPL"); |