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1da177e4 LT |
1 | /* |
2 | * net/sched/sch_tbf.c Token Bucket Filter queue. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public License | |
6 | * as published by the Free Software Foundation; either version | |
7 | * 2 of the License, or (at your option) any later version. | |
8 | * | |
9 | * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> | |
10 | * Dmitry Torokhov <dtor@mail.ru> - allow attaching inner qdiscs - | |
11 | * original idea by Martin Devera | |
12 | * | |
13 | */ | |
14 | ||
1da177e4 LT |
15 | #include <linux/module.h> |
16 | #include <asm/uaccess.h> | |
17 | #include <asm/system.h> | |
18 | #include <linux/bitops.h> | |
19 | #include <linux/types.h> | |
20 | #include <linux/kernel.h> | |
21 | #include <linux/jiffies.h> | |
22 | #include <linux/string.h> | |
23 | #include <linux/mm.h> | |
24 | #include <linux/socket.h> | |
25 | #include <linux/sockios.h> | |
26 | #include <linux/in.h> | |
27 | #include <linux/errno.h> | |
28 | #include <linux/interrupt.h> | |
29 | #include <linux/if_ether.h> | |
30 | #include <linux/inet.h> | |
31 | #include <linux/netdevice.h> | |
32 | #include <linux/etherdevice.h> | |
33 | #include <linux/notifier.h> | |
34 | #include <net/ip.h> | |
35 | #include <net/route.h> | |
36 | #include <linux/skbuff.h> | |
37 | #include <net/sock.h> | |
38 | #include <net/pkt_sched.h> | |
39 | ||
40 | ||
41 | /* Simple Token Bucket Filter. | |
42 | ======================================= | |
43 | ||
44 | SOURCE. | |
45 | ------- | |
46 | ||
47 | None. | |
48 | ||
49 | Description. | |
50 | ------------ | |
51 | ||
52 | A data flow obeys TBF with rate R and depth B, if for any | |
53 | time interval t_i...t_f the number of transmitted bits | |
54 | does not exceed B + R*(t_f-t_i). | |
55 | ||
56 | Packetized version of this definition: | |
57 | The sequence of packets of sizes s_i served at moments t_i | |
58 | obeys TBF, if for any i<=k: | |
59 | ||
60 | s_i+....+s_k <= B + R*(t_k - t_i) | |
61 | ||
62 | Algorithm. | |
63 | ---------- | |
64 | ||
65 | Let N(t_i) be B/R initially and N(t) grow continuously with time as: | |
66 | ||
67 | N(t+delta) = min{B/R, N(t) + delta} | |
68 | ||
69 | If the first packet in queue has length S, it may be | |
70 | transmitted only at the time t_* when S/R <= N(t_*), | |
71 | and in this case N(t) jumps: | |
72 | ||
73 | N(t_* + 0) = N(t_* - 0) - S/R. | |
74 | ||
75 | ||
76 | ||
77 | Actually, QoS requires two TBF to be applied to a data stream. | |
78 | One of them controls steady state burst size, another | |
79 | one with rate P (peak rate) and depth M (equal to link MTU) | |
80 | limits bursts at a smaller time scale. | |
81 | ||
82 | It is easy to see that P>R, and B>M. If P is infinity, this double | |
83 | TBF is equivalent to a single one. | |
84 | ||
85 | When TBF works in reshaping mode, latency is estimated as: | |
86 | ||
87 | lat = max ((L-B)/R, (L-M)/P) | |
88 | ||
89 | ||
90 | NOTES. | |
91 | ------ | |
92 | ||
93 | If TBF throttles, it starts a watchdog timer, which will wake it up | |
94 | when it is ready to transmit. | |
95 | Note that the minimal timer resolution is 1/HZ. | |
96 | If no new packets arrive during this period, | |
97 | or if the device is not awaken by EOI for some previous packet, | |
98 | TBF can stop its activity for 1/HZ. | |
99 | ||
100 | ||
101 | This means, that with depth B, the maximal rate is | |
102 | ||
103 | R_crit = B*HZ | |
104 | ||
105 | F.e. for 10Mbit ethernet and HZ=100 the minimal allowed B is ~10Kbytes. | |
106 | ||
107 | Note that the peak rate TBF is much more tough: with MTU 1500 | |
108 | P_crit = 150Kbytes/sec. So, if you need greater peak | |
109 | rates, use alpha with HZ=1000 :-) | |
110 | ||
111 | With classful TBF, limit is just kept for backwards compatibility. | |
112 | It is passed to the default bfifo qdisc - if the inner qdisc is | |
113 | changed the limit is not effective anymore. | |
114 | */ | |
115 | ||
116 | struct tbf_sched_data | |
117 | { | |
118 | /* Parameters */ | |
119 | u32 limit; /* Maximal length of backlog: bytes */ | |
120 | u32 buffer; /* Token bucket depth/rate: MUST BE >= MTU/B */ | |
121 | u32 mtu; | |
122 | u32 max_size; | |
123 | struct qdisc_rate_table *R_tab; | |
124 | struct qdisc_rate_table *P_tab; | |
125 | ||
126 | /* Variables */ | |
127 | long tokens; /* Current number of B tokens */ | |
128 | long ptokens; /* Current number of P tokens */ | |
129 | psched_time_t t_c; /* Time check-point */ | |
1da177e4 | 130 | struct Qdisc *qdisc; /* Inner qdisc, default - bfifo queue */ |
f7f593e3 | 131 | struct qdisc_watchdog watchdog; /* Watchdog timer */ |
1da177e4 LT |
132 | }; |
133 | ||
134 | #define L2T(q,L) ((q)->R_tab->data[(L)>>(q)->R_tab->rate.cell_log]) | |
135 | #define L2T_P(q,L) ((q)->P_tab->data[(L)>>(q)->P_tab->rate.cell_log]) | |
136 | ||
137 | static int tbf_enqueue(struct sk_buff *skb, struct Qdisc* sch) | |
138 | { | |
139 | struct tbf_sched_data *q = qdisc_priv(sch); | |
140 | int ret; | |
141 | ||
142 | if (skb->len > q->max_size) { | |
143 | sch->qstats.drops++; | |
144 | #ifdef CONFIG_NET_CLS_POLICE | |
145 | if (sch->reshape_fail == NULL || sch->reshape_fail(skb, sch)) | |
146 | #endif | |
147 | kfree_skb(skb); | |
148 | ||
149 | return NET_XMIT_DROP; | |
150 | } | |
151 | ||
152 | if ((ret = q->qdisc->enqueue(skb, q->qdisc)) != 0) { | |
153 | sch->qstats.drops++; | |
154 | return ret; | |
155 | } | |
156 | ||
157 | sch->q.qlen++; | |
158 | sch->bstats.bytes += skb->len; | |
159 | sch->bstats.packets++; | |
160 | return 0; | |
161 | } | |
162 | ||
163 | static int tbf_requeue(struct sk_buff *skb, struct Qdisc* sch) | |
164 | { | |
165 | struct tbf_sched_data *q = qdisc_priv(sch); | |
166 | int ret; | |
167 | ||
168 | if ((ret = q->qdisc->ops->requeue(skb, q->qdisc)) == 0) { | |
169 | sch->q.qlen++; | |
170 | sch->qstats.requeues++; | |
171 | } | |
172 | ||
173 | return ret; | |
174 | } | |
175 | ||
176 | static unsigned int tbf_drop(struct Qdisc* sch) | |
177 | { | |
178 | struct tbf_sched_data *q = qdisc_priv(sch); | |
6d037a26 | 179 | unsigned int len = 0; |
1da177e4 | 180 | |
6d037a26 | 181 | if (q->qdisc->ops->drop && (len = q->qdisc->ops->drop(q->qdisc)) != 0) { |
1da177e4 LT |
182 | sch->q.qlen--; |
183 | sch->qstats.drops++; | |
184 | } | |
185 | return len; | |
186 | } | |
187 | ||
1da177e4 LT |
188 | static struct sk_buff *tbf_dequeue(struct Qdisc* sch) |
189 | { | |
190 | struct tbf_sched_data *q = qdisc_priv(sch); | |
191 | struct sk_buff *skb; | |
192 | ||
193 | skb = q->qdisc->dequeue(q->qdisc); | |
194 | ||
195 | if (skb) { | |
196 | psched_time_t now; | |
f7f593e3 | 197 | long toks; |
1da177e4 LT |
198 | long ptoks = 0; |
199 | unsigned int len = skb->len; | |
200 | ||
201 | PSCHED_GET_TIME(now); | |
202 | ||
203 | toks = PSCHED_TDIFF_SAFE(now, q->t_c, q->buffer); | |
204 | ||
205 | if (q->P_tab) { | |
206 | ptoks = toks + q->ptokens; | |
207 | if (ptoks > (long)q->mtu) | |
208 | ptoks = q->mtu; | |
209 | ptoks -= L2T_P(q, len); | |
210 | } | |
211 | toks += q->tokens; | |
212 | if (toks > (long)q->buffer) | |
213 | toks = q->buffer; | |
214 | toks -= L2T(q, len); | |
215 | ||
216 | if ((toks|ptoks) >= 0) { | |
217 | q->t_c = now; | |
218 | q->tokens = toks; | |
219 | q->ptokens = ptoks; | |
220 | sch->q.qlen--; | |
221 | sch->flags &= ~TCQ_F_THROTTLED; | |
222 | return skb; | |
223 | } | |
224 | ||
f7f593e3 PM |
225 | qdisc_watchdog_schedule(&q->watchdog, |
226 | now + max_t(long, -toks, -ptoks)); | |
1da177e4 LT |
227 | |
228 | /* Maybe we have a shorter packet in the queue, | |
229 | which can be sent now. It sounds cool, | |
230 | but, however, this is wrong in principle. | |
231 | We MUST NOT reorder packets under these circumstances. | |
232 | ||
233 | Really, if we split the flow into independent | |
234 | subflows, it would be a very good solution. | |
235 | This is the main idea of all FQ algorithms | |
236 | (cf. CSZ, HPFQ, HFSC) | |
237 | */ | |
238 | ||
239 | if (q->qdisc->ops->requeue(skb, q->qdisc) != NET_XMIT_SUCCESS) { | |
240 | /* When requeue fails skb is dropped */ | |
e488eafc | 241 | qdisc_tree_decrease_qlen(q->qdisc, 1); |
1da177e4 LT |
242 | sch->qstats.drops++; |
243 | } | |
244 | ||
1da177e4 LT |
245 | sch->qstats.overlimits++; |
246 | } | |
247 | return NULL; | |
248 | } | |
249 | ||
250 | static void tbf_reset(struct Qdisc* sch) | |
251 | { | |
252 | struct tbf_sched_data *q = qdisc_priv(sch); | |
253 | ||
254 | qdisc_reset(q->qdisc); | |
255 | sch->q.qlen = 0; | |
256 | PSCHED_GET_TIME(q->t_c); | |
257 | q->tokens = q->buffer; | |
258 | q->ptokens = q->mtu; | |
f7f593e3 | 259 | qdisc_watchdog_cancel(&q->watchdog); |
1da177e4 LT |
260 | } |
261 | ||
9f9afec4 | 262 | static struct Qdisc *tbf_create_dflt_qdisc(struct Qdisc *sch, u32 limit) |
1da177e4 | 263 | { |
9f9afec4 | 264 | struct Qdisc *q; |
10297b99 | 265 | struct rtattr *rta; |
1da177e4 LT |
266 | int ret; |
267 | ||
9f9afec4 PM |
268 | q = qdisc_create_dflt(sch->dev, &bfifo_qdisc_ops, |
269 | TC_H_MAKE(sch->handle, 1)); | |
1da177e4 LT |
270 | if (q) { |
271 | rta = kmalloc(RTA_LENGTH(sizeof(struct tc_fifo_qopt)), GFP_KERNEL); | |
272 | if (rta) { | |
273 | rta->rta_type = RTM_NEWQDISC; | |
10297b99 | 274 | rta->rta_len = RTA_LENGTH(sizeof(struct tc_fifo_qopt)); |
1da177e4 LT |
275 | ((struct tc_fifo_qopt *)RTA_DATA(rta))->limit = limit; |
276 | ||
277 | ret = q->ops->change(q, rta); | |
278 | kfree(rta); | |
279 | ||
280 | if (ret == 0) | |
281 | return q; | |
282 | } | |
283 | qdisc_destroy(q); | |
284 | } | |
285 | ||
286 | return NULL; | |
287 | } | |
288 | ||
289 | static int tbf_change(struct Qdisc* sch, struct rtattr *opt) | |
290 | { | |
291 | int err = -EINVAL; | |
292 | struct tbf_sched_data *q = qdisc_priv(sch); | |
293 | struct rtattr *tb[TCA_TBF_PTAB]; | |
294 | struct tc_tbf_qopt *qopt; | |
295 | struct qdisc_rate_table *rtab = NULL; | |
296 | struct qdisc_rate_table *ptab = NULL; | |
297 | struct Qdisc *child = NULL; | |
298 | int max_size,n; | |
299 | ||
300 | if (rtattr_parse_nested(tb, TCA_TBF_PTAB, opt) || | |
301 | tb[TCA_TBF_PARMS-1] == NULL || | |
302 | RTA_PAYLOAD(tb[TCA_TBF_PARMS-1]) < sizeof(*qopt)) | |
303 | goto done; | |
304 | ||
305 | qopt = RTA_DATA(tb[TCA_TBF_PARMS-1]); | |
306 | rtab = qdisc_get_rtab(&qopt->rate, tb[TCA_TBF_RTAB-1]); | |
307 | if (rtab == NULL) | |
308 | goto done; | |
309 | ||
310 | if (qopt->peakrate.rate) { | |
311 | if (qopt->peakrate.rate > qopt->rate.rate) | |
312 | ptab = qdisc_get_rtab(&qopt->peakrate, tb[TCA_TBF_PTAB-1]); | |
313 | if (ptab == NULL) | |
314 | goto done; | |
315 | } | |
316 | ||
317 | for (n = 0; n < 256; n++) | |
318 | if (rtab->data[n] > qopt->buffer) break; | |
319 | max_size = (n << qopt->rate.cell_log)-1; | |
320 | if (ptab) { | |
321 | int size; | |
322 | ||
323 | for (n = 0; n < 256; n++) | |
324 | if (ptab->data[n] > qopt->mtu) break; | |
325 | size = (n << qopt->peakrate.cell_log)-1; | |
326 | if (size < max_size) max_size = size; | |
327 | } | |
328 | if (max_size < 0) | |
329 | goto done; | |
330 | ||
053cfed7 | 331 | if (qopt->limit > 0) { |
9f9afec4 | 332 | if ((child = tbf_create_dflt_qdisc(sch, qopt->limit)) == NULL) |
1da177e4 LT |
333 | goto done; |
334 | } | |
335 | ||
336 | sch_tree_lock(sch); | |
5e50da01 PM |
337 | if (child) { |
338 | qdisc_tree_decrease_qlen(q->qdisc, q->qdisc->q.qlen); | |
053cfed7 | 339 | qdisc_destroy(xchg(&q->qdisc, child)); |
5e50da01 | 340 | } |
1da177e4 LT |
341 | q->limit = qopt->limit; |
342 | q->mtu = qopt->mtu; | |
343 | q->max_size = max_size; | |
344 | q->buffer = qopt->buffer; | |
345 | q->tokens = q->buffer; | |
346 | q->ptokens = q->mtu; | |
347 | rtab = xchg(&q->R_tab, rtab); | |
348 | ptab = xchg(&q->P_tab, ptab); | |
349 | sch_tree_unlock(sch); | |
350 | err = 0; | |
351 | done: | |
352 | if (rtab) | |
353 | qdisc_put_rtab(rtab); | |
354 | if (ptab) | |
355 | qdisc_put_rtab(ptab); | |
356 | return err; | |
357 | } | |
358 | ||
359 | static int tbf_init(struct Qdisc* sch, struct rtattr *opt) | |
360 | { | |
361 | struct tbf_sched_data *q = qdisc_priv(sch); | |
362 | ||
363 | if (opt == NULL) | |
364 | return -EINVAL; | |
365 | ||
366 | PSCHED_GET_TIME(q->t_c); | |
f7f593e3 | 367 | qdisc_watchdog_init(&q->watchdog, sch); |
1da177e4 LT |
368 | q->qdisc = &noop_qdisc; |
369 | ||
370 | return tbf_change(sch, opt); | |
371 | } | |
372 | ||
373 | static void tbf_destroy(struct Qdisc *sch) | |
374 | { | |
375 | struct tbf_sched_data *q = qdisc_priv(sch); | |
376 | ||
f7f593e3 | 377 | qdisc_watchdog_cancel(&q->watchdog); |
1da177e4 LT |
378 | |
379 | if (q->P_tab) | |
380 | qdisc_put_rtab(q->P_tab); | |
381 | if (q->R_tab) | |
382 | qdisc_put_rtab(q->R_tab); | |
383 | ||
384 | qdisc_destroy(q->qdisc); | |
385 | } | |
386 | ||
387 | static int tbf_dump(struct Qdisc *sch, struct sk_buff *skb) | |
388 | { | |
389 | struct tbf_sched_data *q = qdisc_priv(sch); | |
27a884dc | 390 | unsigned char *b = skb_tail_pointer(skb); |
1da177e4 LT |
391 | struct rtattr *rta; |
392 | struct tc_tbf_qopt opt; | |
393 | ||
394 | rta = (struct rtattr*)b; | |
395 | RTA_PUT(skb, TCA_OPTIONS, 0, NULL); | |
396 | ||
397 | opt.limit = q->limit; | |
398 | opt.rate = q->R_tab->rate; | |
399 | if (q->P_tab) | |
400 | opt.peakrate = q->P_tab->rate; | |
401 | else | |
402 | memset(&opt.peakrate, 0, sizeof(opt.peakrate)); | |
403 | opt.mtu = q->mtu; | |
404 | opt.buffer = q->buffer; | |
405 | RTA_PUT(skb, TCA_TBF_PARMS, sizeof(opt), &opt); | |
27a884dc | 406 | rta->rta_len = skb_tail_pointer(skb) - b; |
1da177e4 LT |
407 | |
408 | return skb->len; | |
409 | ||
410 | rtattr_failure: | |
411 | skb_trim(skb, b - skb->data); | |
412 | return -1; | |
413 | } | |
414 | ||
415 | static int tbf_dump_class(struct Qdisc *sch, unsigned long cl, | |
416 | struct sk_buff *skb, struct tcmsg *tcm) | |
417 | { | |
418 | struct tbf_sched_data *q = qdisc_priv(sch); | |
419 | ||
420 | if (cl != 1) /* only one class */ | |
421 | return -ENOENT; | |
422 | ||
423 | tcm->tcm_handle |= TC_H_MIN(1); | |
424 | tcm->tcm_info = q->qdisc->handle; | |
425 | ||
426 | return 0; | |
427 | } | |
428 | ||
429 | static int tbf_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, | |
430 | struct Qdisc **old) | |
431 | { | |
432 | struct tbf_sched_data *q = qdisc_priv(sch); | |
433 | ||
434 | if (new == NULL) | |
435 | new = &noop_qdisc; | |
436 | ||
437 | sch_tree_lock(sch); | |
438 | *old = xchg(&q->qdisc, new); | |
5e50da01 | 439 | qdisc_tree_decrease_qlen(*old, (*old)->q.qlen); |
1da177e4 | 440 | qdisc_reset(*old); |
1da177e4 LT |
441 | sch_tree_unlock(sch); |
442 | ||
443 | return 0; | |
444 | } | |
445 | ||
446 | static struct Qdisc *tbf_leaf(struct Qdisc *sch, unsigned long arg) | |
447 | { | |
448 | struct tbf_sched_data *q = qdisc_priv(sch); | |
449 | return q->qdisc; | |
450 | } | |
451 | ||
452 | static unsigned long tbf_get(struct Qdisc *sch, u32 classid) | |
453 | { | |
454 | return 1; | |
455 | } | |
456 | ||
457 | static void tbf_put(struct Qdisc *sch, unsigned long arg) | |
458 | { | |
459 | } | |
460 | ||
10297b99 | 461 | static int tbf_change_class(struct Qdisc *sch, u32 classid, u32 parentid, |
1da177e4 LT |
462 | struct rtattr **tca, unsigned long *arg) |
463 | { | |
464 | return -ENOSYS; | |
465 | } | |
466 | ||
467 | static int tbf_delete(struct Qdisc *sch, unsigned long arg) | |
468 | { | |
469 | return -ENOSYS; | |
470 | } | |
471 | ||
472 | static void tbf_walk(struct Qdisc *sch, struct qdisc_walker *walker) | |
473 | { | |
474 | if (!walker->stop) { | |
475 | if (walker->count >= walker->skip) | |
476 | if (walker->fn(sch, 1, walker) < 0) { | |
477 | walker->stop = 1; | |
478 | return; | |
479 | } | |
480 | walker->count++; | |
481 | } | |
482 | } | |
483 | ||
484 | static struct tcf_proto **tbf_find_tcf(struct Qdisc *sch, unsigned long cl) | |
485 | { | |
486 | return NULL; | |
487 | } | |
488 | ||
489 | static struct Qdisc_class_ops tbf_class_ops = | |
490 | { | |
491 | .graft = tbf_graft, | |
492 | .leaf = tbf_leaf, | |
493 | .get = tbf_get, | |
494 | .put = tbf_put, | |
495 | .change = tbf_change_class, | |
496 | .delete = tbf_delete, | |
497 | .walk = tbf_walk, | |
498 | .tcf_chain = tbf_find_tcf, | |
499 | .dump = tbf_dump_class, | |
500 | }; | |
501 | ||
502 | static struct Qdisc_ops tbf_qdisc_ops = { | |
503 | .next = NULL, | |
504 | .cl_ops = &tbf_class_ops, | |
505 | .id = "tbf", | |
506 | .priv_size = sizeof(struct tbf_sched_data), | |
507 | .enqueue = tbf_enqueue, | |
508 | .dequeue = tbf_dequeue, | |
509 | .requeue = tbf_requeue, | |
510 | .drop = tbf_drop, | |
511 | .init = tbf_init, | |
512 | .reset = tbf_reset, | |
513 | .destroy = tbf_destroy, | |
514 | .change = tbf_change, | |
515 | .dump = tbf_dump, | |
516 | .owner = THIS_MODULE, | |
517 | }; | |
518 | ||
519 | static int __init tbf_module_init(void) | |
520 | { | |
521 | return register_qdisc(&tbf_qdisc_ops); | |
522 | } | |
523 | ||
524 | static void __exit tbf_module_exit(void) | |
525 | { | |
526 | unregister_qdisc(&tbf_qdisc_ops); | |
527 | } | |
528 | module_init(tbf_module_init) | |
529 | module_exit(tbf_module_exit) | |
530 | MODULE_LICENSE("GPL"); |