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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> | |
dc5fc579 | 35 | #include <net/netlink.h> |
1da177e4 LT |
36 | #include <net/route.h> |
37 | #include <linux/skbuff.h> | |
38 | #include <net/sock.h> | |
39 | #include <net/pkt_sched.h> | |
40 | ||
41 | ||
42 | /* Simple Token Bucket Filter. | |
43 | ======================================= | |
44 | ||
45 | SOURCE. | |
46 | ------- | |
47 | ||
48 | None. | |
49 | ||
50 | Description. | |
51 | ------------ | |
52 | ||
53 | A data flow obeys TBF with rate R and depth B, if for any | |
54 | time interval t_i...t_f the number of transmitted bits | |
55 | does not exceed B + R*(t_f-t_i). | |
56 | ||
57 | Packetized version of this definition: | |
58 | The sequence of packets of sizes s_i served at moments t_i | |
59 | obeys TBF, if for any i<=k: | |
60 | ||
61 | s_i+....+s_k <= B + R*(t_k - t_i) | |
62 | ||
63 | Algorithm. | |
64 | ---------- | |
65 | ||
66 | Let N(t_i) be B/R initially and N(t) grow continuously with time as: | |
67 | ||
68 | N(t+delta) = min{B/R, N(t) + delta} | |
69 | ||
70 | If the first packet in queue has length S, it may be | |
71 | transmitted only at the time t_* when S/R <= N(t_*), | |
72 | and in this case N(t) jumps: | |
73 | ||
74 | N(t_* + 0) = N(t_* - 0) - S/R. | |
75 | ||
76 | ||
77 | ||
78 | Actually, QoS requires two TBF to be applied to a data stream. | |
79 | One of them controls steady state burst size, another | |
80 | one with rate P (peak rate) and depth M (equal to link MTU) | |
81 | limits bursts at a smaller time scale. | |
82 | ||
83 | It is easy to see that P>R, and B>M. If P is infinity, this double | |
84 | TBF is equivalent to a single one. | |
85 | ||
86 | When TBF works in reshaping mode, latency is estimated as: | |
87 | ||
88 | lat = max ((L-B)/R, (L-M)/P) | |
89 | ||
90 | ||
91 | NOTES. | |
92 | ------ | |
93 | ||
94 | If TBF throttles, it starts a watchdog timer, which will wake it up | |
95 | when it is ready to transmit. | |
96 | Note that the minimal timer resolution is 1/HZ. | |
97 | If no new packets arrive during this period, | |
98 | or if the device is not awaken by EOI for some previous packet, | |
99 | TBF can stop its activity for 1/HZ. | |
100 | ||
101 | ||
102 | This means, that with depth B, the maximal rate is | |
103 | ||
104 | R_crit = B*HZ | |
105 | ||
106 | F.e. for 10Mbit ethernet and HZ=100 the minimal allowed B is ~10Kbytes. | |
107 | ||
108 | Note that the peak rate TBF is much more tough: with MTU 1500 | |
109 | P_crit = 150Kbytes/sec. So, if you need greater peak | |
110 | rates, use alpha with HZ=1000 :-) | |
111 | ||
112 | With classful TBF, limit is just kept for backwards compatibility. | |
113 | It is passed to the default bfifo qdisc - if the inner qdisc is | |
114 | changed the limit is not effective anymore. | |
115 | */ | |
116 | ||
117 | struct tbf_sched_data | |
118 | { | |
119 | /* Parameters */ | |
120 | u32 limit; /* Maximal length of backlog: bytes */ | |
121 | u32 buffer; /* Token bucket depth/rate: MUST BE >= MTU/B */ | |
122 | u32 mtu; | |
123 | u32 max_size; | |
124 | struct qdisc_rate_table *R_tab; | |
125 | struct qdisc_rate_table *P_tab; | |
126 | ||
127 | /* Variables */ | |
128 | long tokens; /* Current number of B tokens */ | |
129 | long ptokens; /* Current number of P tokens */ | |
130 | psched_time_t t_c; /* Time check-point */ | |
1da177e4 | 131 | struct Qdisc *qdisc; /* Inner qdisc, default - bfifo queue */ |
f7f593e3 | 132 | struct qdisc_watchdog watchdog; /* Watchdog timer */ |
1da177e4 LT |
133 | }; |
134 | ||
135 | #define L2T(q,L) ((q)->R_tab->data[(L)>>(q)->R_tab->rate.cell_log]) | |
136 | #define L2T_P(q,L) ((q)->P_tab->data[(L)>>(q)->P_tab->rate.cell_log]) | |
137 | ||
138 | static int tbf_enqueue(struct sk_buff *skb, struct Qdisc* sch) | |
139 | { | |
140 | struct tbf_sched_data *q = qdisc_priv(sch); | |
141 | int ret; | |
142 | ||
143 | if (skb->len > q->max_size) { | |
144 | sch->qstats.drops++; | |
145 | #ifdef CONFIG_NET_CLS_POLICE | |
146 | if (sch->reshape_fail == NULL || sch->reshape_fail(skb, sch)) | |
147 | #endif | |
148 | kfree_skb(skb); | |
149 | ||
150 | return NET_XMIT_DROP; | |
151 | } | |
152 | ||
153 | if ((ret = q->qdisc->enqueue(skb, q->qdisc)) != 0) { | |
154 | sch->qstats.drops++; | |
155 | return ret; | |
156 | } | |
157 | ||
158 | sch->q.qlen++; | |
159 | sch->bstats.bytes += skb->len; | |
160 | sch->bstats.packets++; | |
161 | return 0; | |
162 | } | |
163 | ||
164 | static int tbf_requeue(struct sk_buff *skb, struct Qdisc* sch) | |
165 | { | |
166 | struct tbf_sched_data *q = qdisc_priv(sch); | |
167 | int ret; | |
168 | ||
169 | if ((ret = q->qdisc->ops->requeue(skb, q->qdisc)) == 0) { | |
170 | sch->q.qlen++; | |
171 | sch->qstats.requeues++; | |
172 | } | |
173 | ||
174 | return ret; | |
175 | } | |
176 | ||
177 | static unsigned int tbf_drop(struct Qdisc* sch) | |
178 | { | |
179 | struct tbf_sched_data *q = qdisc_priv(sch); | |
6d037a26 | 180 | unsigned int len = 0; |
1da177e4 | 181 | |
6d037a26 | 182 | if (q->qdisc->ops->drop && (len = q->qdisc->ops->drop(q->qdisc)) != 0) { |
1da177e4 LT |
183 | sch->q.qlen--; |
184 | sch->qstats.drops++; | |
185 | } | |
186 | return len; | |
187 | } | |
188 | ||
1da177e4 LT |
189 | static struct sk_buff *tbf_dequeue(struct Qdisc* sch) |
190 | { | |
191 | struct tbf_sched_data *q = qdisc_priv(sch); | |
192 | struct sk_buff *skb; | |
193 | ||
194 | skb = q->qdisc->dequeue(q->qdisc); | |
195 | ||
196 | if (skb) { | |
197 | psched_time_t now; | |
f7f593e3 | 198 | long toks; |
1da177e4 LT |
199 | long ptoks = 0; |
200 | unsigned int len = skb->len; | |
201 | ||
202 | PSCHED_GET_TIME(now); | |
203 | ||
204 | toks = PSCHED_TDIFF_SAFE(now, q->t_c, q->buffer); | |
205 | ||
206 | if (q->P_tab) { | |
207 | ptoks = toks + q->ptokens; | |
208 | if (ptoks > (long)q->mtu) | |
209 | ptoks = q->mtu; | |
210 | ptoks -= L2T_P(q, len); | |
211 | } | |
212 | toks += q->tokens; | |
213 | if (toks > (long)q->buffer) | |
214 | toks = q->buffer; | |
215 | toks -= L2T(q, len); | |
216 | ||
217 | if ((toks|ptoks) >= 0) { | |
218 | q->t_c = now; | |
219 | q->tokens = toks; | |
220 | q->ptokens = ptoks; | |
221 | sch->q.qlen--; | |
222 | sch->flags &= ~TCQ_F_THROTTLED; | |
223 | return skb; | |
224 | } | |
225 | ||
f7f593e3 PM |
226 | qdisc_watchdog_schedule(&q->watchdog, |
227 | now + max_t(long, -toks, -ptoks)); | |
1da177e4 LT |
228 | |
229 | /* Maybe we have a shorter packet in the queue, | |
230 | which can be sent now. It sounds cool, | |
231 | but, however, this is wrong in principle. | |
232 | We MUST NOT reorder packets under these circumstances. | |
233 | ||
234 | Really, if we split the flow into independent | |
235 | subflows, it would be a very good solution. | |
236 | This is the main idea of all FQ algorithms | |
237 | (cf. CSZ, HPFQ, HFSC) | |
238 | */ | |
239 | ||
240 | if (q->qdisc->ops->requeue(skb, q->qdisc) != NET_XMIT_SUCCESS) { | |
241 | /* When requeue fails skb is dropped */ | |
e488eafc | 242 | qdisc_tree_decrease_qlen(q->qdisc, 1); |
1da177e4 LT |
243 | sch->qstats.drops++; |
244 | } | |
245 | ||
1da177e4 LT |
246 | sch->qstats.overlimits++; |
247 | } | |
248 | return NULL; | |
249 | } | |
250 | ||
251 | static void tbf_reset(struct Qdisc* sch) | |
252 | { | |
253 | struct tbf_sched_data *q = qdisc_priv(sch); | |
254 | ||
255 | qdisc_reset(q->qdisc); | |
256 | sch->q.qlen = 0; | |
257 | PSCHED_GET_TIME(q->t_c); | |
258 | q->tokens = q->buffer; | |
259 | q->ptokens = q->mtu; | |
f7f593e3 | 260 | qdisc_watchdog_cancel(&q->watchdog); |
1da177e4 LT |
261 | } |
262 | ||
9f9afec4 | 263 | static struct Qdisc *tbf_create_dflt_qdisc(struct Qdisc *sch, u32 limit) |
1da177e4 | 264 | { |
9f9afec4 | 265 | struct Qdisc *q; |
10297b99 | 266 | struct rtattr *rta; |
1da177e4 LT |
267 | int ret; |
268 | ||
9f9afec4 PM |
269 | q = qdisc_create_dflt(sch->dev, &bfifo_qdisc_ops, |
270 | TC_H_MAKE(sch->handle, 1)); | |
1da177e4 LT |
271 | if (q) { |
272 | rta = kmalloc(RTA_LENGTH(sizeof(struct tc_fifo_qopt)), GFP_KERNEL); | |
273 | if (rta) { | |
274 | rta->rta_type = RTM_NEWQDISC; | |
10297b99 | 275 | rta->rta_len = RTA_LENGTH(sizeof(struct tc_fifo_qopt)); |
1da177e4 LT |
276 | ((struct tc_fifo_qopt *)RTA_DATA(rta))->limit = limit; |
277 | ||
278 | ret = q->ops->change(q, rta); | |
279 | kfree(rta); | |
280 | ||
281 | if (ret == 0) | |
282 | return q; | |
283 | } | |
284 | qdisc_destroy(q); | |
285 | } | |
286 | ||
287 | return NULL; | |
288 | } | |
289 | ||
290 | static int tbf_change(struct Qdisc* sch, struct rtattr *opt) | |
291 | { | |
292 | int err = -EINVAL; | |
293 | struct tbf_sched_data *q = qdisc_priv(sch); | |
294 | struct rtattr *tb[TCA_TBF_PTAB]; | |
295 | struct tc_tbf_qopt *qopt; | |
296 | struct qdisc_rate_table *rtab = NULL; | |
297 | struct qdisc_rate_table *ptab = NULL; | |
298 | struct Qdisc *child = NULL; | |
299 | int max_size,n; | |
300 | ||
301 | if (rtattr_parse_nested(tb, TCA_TBF_PTAB, opt) || | |
302 | tb[TCA_TBF_PARMS-1] == NULL || | |
303 | RTA_PAYLOAD(tb[TCA_TBF_PARMS-1]) < sizeof(*qopt)) | |
304 | goto done; | |
305 | ||
306 | qopt = RTA_DATA(tb[TCA_TBF_PARMS-1]); | |
307 | rtab = qdisc_get_rtab(&qopt->rate, tb[TCA_TBF_RTAB-1]); | |
308 | if (rtab == NULL) | |
309 | goto done; | |
310 | ||
311 | if (qopt->peakrate.rate) { | |
312 | if (qopt->peakrate.rate > qopt->rate.rate) | |
313 | ptab = qdisc_get_rtab(&qopt->peakrate, tb[TCA_TBF_PTAB-1]); | |
314 | if (ptab == NULL) | |
315 | goto done; | |
316 | } | |
317 | ||
318 | for (n = 0; n < 256; n++) | |
319 | if (rtab->data[n] > qopt->buffer) break; | |
320 | max_size = (n << qopt->rate.cell_log)-1; | |
321 | if (ptab) { | |
322 | int size; | |
323 | ||
324 | for (n = 0; n < 256; n++) | |
325 | if (ptab->data[n] > qopt->mtu) break; | |
326 | size = (n << qopt->peakrate.cell_log)-1; | |
327 | if (size < max_size) max_size = size; | |
328 | } | |
329 | if (max_size < 0) | |
330 | goto done; | |
331 | ||
053cfed7 | 332 | if (qopt->limit > 0) { |
9f9afec4 | 333 | if ((child = tbf_create_dflt_qdisc(sch, qopt->limit)) == NULL) |
1da177e4 LT |
334 | goto done; |
335 | } | |
336 | ||
337 | sch_tree_lock(sch); | |
5e50da01 PM |
338 | if (child) { |
339 | qdisc_tree_decrease_qlen(q->qdisc, q->qdisc->q.qlen); | |
053cfed7 | 340 | qdisc_destroy(xchg(&q->qdisc, child)); |
5e50da01 | 341 | } |
1da177e4 LT |
342 | q->limit = qopt->limit; |
343 | q->mtu = qopt->mtu; | |
344 | q->max_size = max_size; | |
345 | q->buffer = qopt->buffer; | |
346 | q->tokens = q->buffer; | |
347 | q->ptokens = q->mtu; | |
348 | rtab = xchg(&q->R_tab, rtab); | |
349 | ptab = xchg(&q->P_tab, ptab); | |
350 | sch_tree_unlock(sch); | |
351 | err = 0; | |
352 | done: | |
353 | if (rtab) | |
354 | qdisc_put_rtab(rtab); | |
355 | if (ptab) | |
356 | qdisc_put_rtab(ptab); | |
357 | return err; | |
358 | } | |
359 | ||
360 | static int tbf_init(struct Qdisc* sch, struct rtattr *opt) | |
361 | { | |
362 | struct tbf_sched_data *q = qdisc_priv(sch); | |
363 | ||
364 | if (opt == NULL) | |
365 | return -EINVAL; | |
366 | ||
367 | PSCHED_GET_TIME(q->t_c); | |
f7f593e3 | 368 | qdisc_watchdog_init(&q->watchdog, sch); |
1da177e4 LT |
369 | q->qdisc = &noop_qdisc; |
370 | ||
371 | return tbf_change(sch, opt); | |
372 | } | |
373 | ||
374 | static void tbf_destroy(struct Qdisc *sch) | |
375 | { | |
376 | struct tbf_sched_data *q = qdisc_priv(sch); | |
377 | ||
f7f593e3 | 378 | qdisc_watchdog_cancel(&q->watchdog); |
1da177e4 LT |
379 | |
380 | if (q->P_tab) | |
381 | qdisc_put_rtab(q->P_tab); | |
382 | if (q->R_tab) | |
383 | qdisc_put_rtab(q->R_tab); | |
384 | ||
385 | qdisc_destroy(q->qdisc); | |
386 | } | |
387 | ||
388 | static int tbf_dump(struct Qdisc *sch, struct sk_buff *skb) | |
389 | { | |
390 | struct tbf_sched_data *q = qdisc_priv(sch); | |
27a884dc | 391 | unsigned char *b = skb_tail_pointer(skb); |
1da177e4 LT |
392 | struct rtattr *rta; |
393 | struct tc_tbf_qopt opt; | |
394 | ||
395 | rta = (struct rtattr*)b; | |
396 | RTA_PUT(skb, TCA_OPTIONS, 0, NULL); | |
397 | ||
398 | opt.limit = q->limit; | |
399 | opt.rate = q->R_tab->rate; | |
400 | if (q->P_tab) | |
401 | opt.peakrate = q->P_tab->rate; | |
402 | else | |
403 | memset(&opt.peakrate, 0, sizeof(opt.peakrate)); | |
404 | opt.mtu = q->mtu; | |
405 | opt.buffer = q->buffer; | |
406 | RTA_PUT(skb, TCA_TBF_PARMS, sizeof(opt), &opt); | |
27a884dc | 407 | rta->rta_len = skb_tail_pointer(skb) - b; |
1da177e4 LT |
408 | |
409 | return skb->len; | |
410 | ||
411 | rtattr_failure: | |
dc5fc579 | 412 | nlmsg_trim(skb, b); |
1da177e4 LT |
413 | return -1; |
414 | } | |
415 | ||
416 | static int tbf_dump_class(struct Qdisc *sch, unsigned long cl, | |
417 | struct sk_buff *skb, struct tcmsg *tcm) | |
418 | { | |
419 | struct tbf_sched_data *q = qdisc_priv(sch); | |
420 | ||
421 | if (cl != 1) /* only one class */ | |
422 | return -ENOENT; | |
423 | ||
424 | tcm->tcm_handle |= TC_H_MIN(1); | |
425 | tcm->tcm_info = q->qdisc->handle; | |
426 | ||
427 | return 0; | |
428 | } | |
429 | ||
430 | static int tbf_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, | |
431 | struct Qdisc **old) | |
432 | { | |
433 | struct tbf_sched_data *q = qdisc_priv(sch); | |
434 | ||
435 | if (new == NULL) | |
436 | new = &noop_qdisc; | |
437 | ||
438 | sch_tree_lock(sch); | |
439 | *old = xchg(&q->qdisc, new); | |
5e50da01 | 440 | qdisc_tree_decrease_qlen(*old, (*old)->q.qlen); |
1da177e4 | 441 | qdisc_reset(*old); |
1da177e4 LT |
442 | sch_tree_unlock(sch); |
443 | ||
444 | return 0; | |
445 | } | |
446 | ||
447 | static struct Qdisc *tbf_leaf(struct Qdisc *sch, unsigned long arg) | |
448 | { | |
449 | struct tbf_sched_data *q = qdisc_priv(sch); | |
450 | return q->qdisc; | |
451 | } | |
452 | ||
453 | static unsigned long tbf_get(struct Qdisc *sch, u32 classid) | |
454 | { | |
455 | return 1; | |
456 | } | |
457 | ||
458 | static void tbf_put(struct Qdisc *sch, unsigned long arg) | |
459 | { | |
460 | } | |
461 | ||
10297b99 | 462 | static int tbf_change_class(struct Qdisc *sch, u32 classid, u32 parentid, |
1da177e4 LT |
463 | struct rtattr **tca, unsigned long *arg) |
464 | { | |
465 | return -ENOSYS; | |
466 | } | |
467 | ||
468 | static int tbf_delete(struct Qdisc *sch, unsigned long arg) | |
469 | { | |
470 | return -ENOSYS; | |
471 | } | |
472 | ||
473 | static void tbf_walk(struct Qdisc *sch, struct qdisc_walker *walker) | |
474 | { | |
475 | if (!walker->stop) { | |
476 | if (walker->count >= walker->skip) | |
477 | if (walker->fn(sch, 1, walker) < 0) { | |
478 | walker->stop = 1; | |
479 | return; | |
480 | } | |
481 | walker->count++; | |
482 | } | |
483 | } | |
484 | ||
485 | static struct tcf_proto **tbf_find_tcf(struct Qdisc *sch, unsigned long cl) | |
486 | { | |
487 | return NULL; | |
488 | } | |
489 | ||
490 | static struct Qdisc_class_ops tbf_class_ops = | |
491 | { | |
492 | .graft = tbf_graft, | |
493 | .leaf = tbf_leaf, | |
494 | .get = tbf_get, | |
495 | .put = tbf_put, | |
496 | .change = tbf_change_class, | |
497 | .delete = tbf_delete, | |
498 | .walk = tbf_walk, | |
499 | .tcf_chain = tbf_find_tcf, | |
500 | .dump = tbf_dump_class, | |
501 | }; | |
502 | ||
503 | static struct Qdisc_ops tbf_qdisc_ops = { | |
504 | .next = NULL, | |
505 | .cl_ops = &tbf_class_ops, | |
506 | .id = "tbf", | |
507 | .priv_size = sizeof(struct tbf_sched_data), | |
508 | .enqueue = tbf_enqueue, | |
509 | .dequeue = tbf_dequeue, | |
510 | .requeue = tbf_requeue, | |
511 | .drop = tbf_drop, | |
512 | .init = tbf_init, | |
513 | .reset = tbf_reset, | |
514 | .destroy = tbf_destroy, | |
515 | .change = tbf_change, | |
516 | .dump = tbf_dump, | |
517 | .owner = THIS_MODULE, | |
518 | }; | |
519 | ||
520 | static int __init tbf_module_init(void) | |
521 | { | |
522 | return register_qdisc(&tbf_qdisc_ops); | |
523 | } | |
524 | ||
525 | static void __exit tbf_module_exit(void) | |
526 | { | |
527 | unregister_qdisc(&tbf_qdisc_ops); | |
528 | } | |
529 | module_init(tbf_module_init) | |
530 | module_exit(tbf_module_exit) | |
531 | MODULE_LICENSE("GPL"); |