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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> | |
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> | |
1da177e4 LT |
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> | |
14c85021 | 24 | #include <linux/if_arp.h> |
1da177e4 LT |
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 | } | |
10297b99 | 180 | |
1da177e4 LT |
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 | { | |
2941a486 | 276 | struct teql_master *master = netdev_priv(dev); |
1da177e4 LT |
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; | |
10297b99 | 294 | |
1da177e4 LT |
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: | |
932ff279 | 304 | if (netif_tx_trylock(slave)) { |
1da177e4 LT |
305 | if (!netif_queue_stopped(slave) && |
306 | slave->hard_start_xmit(skb, slave) == 0) { | |
932ff279 | 307 | netif_tx_unlock(slave); |
1da177e4 LT |
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 | } | |
932ff279 | 314 | netif_tx_unlock(slave); |
1da177e4 LT |
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 | } | |
bbe735e4 | 326 | __skb_pull(skb, skb_network_offset(skb)); |
1da177e4 LT |
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; | |
2941a486 | 349 | struct teql_master *m = netdev_priv(dev); |
1da177e4 LT |
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 | { | |
2941a486 | 396 | struct teql_master *m = netdev_priv(dev); |
1da177e4 LT |
397 | return &m->stats; |
398 | } | |
399 | ||
400 | static int teql_master_mtu(struct net_device *dev, int new_mtu) | |
401 | { | |
2941a486 | 402 | struct teql_master *m = netdev_priv(dev); |
1da177e4 LT |
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 | { | |
2941a486 | 422 | struct teql_master *master = netdev_priv(dev); |
1da177e4 LT |
423 | struct Qdisc_ops *ops = &master->qops; |
424 | ||
425 | master->dev = dev; | |
426 | ops->priv_size = sizeof(struct teql_sched_data); | |
10297b99 | 427 | |
1da177e4 LT |
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 | ||
2941a486 | 475 | master = netdev_priv(dev); |
1da177e4 LT |
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 | ||
10297b99 | 491 | static void __exit teql_exit(void) |
1da177e4 LT |
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"); |