blob: 6c4ad7e677b3486e43a65cc2a3424f7dbc15ec7f [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#include <linux/module.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <linux/types.h>
17#include <linux/kernel.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070018#include <linux/string.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070019#include <linux/errno.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070020#include <linux/skbuff.h>
Patrick McHardy0ba48052007-07-02 22:49:07 -070021#include <net/netlink.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022#include <net/pkt_sched.h>
23
24
25/* Simple Token Bucket Filter.
26 =======================================
27
28 SOURCE.
29 -------
30
31 None.
32
33 Description.
34 ------------
35
36 A data flow obeys TBF with rate R and depth B, if for any
37 time interval t_i...t_f the number of transmitted bits
38 does not exceed B + R*(t_f-t_i).
39
40 Packetized version of this definition:
41 The sequence of packets of sizes s_i served at moments t_i
42 obeys TBF, if for any i<=k:
43
44 s_i+....+s_k <= B + R*(t_k - t_i)
45
46 Algorithm.
47 ----------
48
49 Let N(t_i) be B/R initially and N(t) grow continuously with time as:
50
51 N(t+delta) = min{B/R, N(t) + delta}
52
53 If the first packet in queue has length S, it may be
54 transmitted only at the time t_* when S/R <= N(t_*),
55 and in this case N(t) jumps:
56
57 N(t_* + 0) = N(t_* - 0) - S/R.
58
59
60
61 Actually, QoS requires two TBF to be applied to a data stream.
62 One of them controls steady state burst size, another
63 one with rate P (peak rate) and depth M (equal to link MTU)
64 limits bursts at a smaller time scale.
65
66 It is easy to see that P>R, and B>M. If P is infinity, this double
67 TBF is equivalent to a single one.
68
69 When TBF works in reshaping mode, latency is estimated as:
70
71 lat = max ((L-B)/R, (L-M)/P)
72
73
74 NOTES.
75 ------
76
77 If TBF throttles, it starts a watchdog timer, which will wake it up
78 when it is ready to transmit.
79 Note that the minimal timer resolution is 1/HZ.
80 If no new packets arrive during this period,
81 or if the device is not awaken by EOI for some previous packet,
82 TBF can stop its activity for 1/HZ.
83
84
85 This means, that with depth B, the maximal rate is
86
87 R_crit = B*HZ
88
89 F.e. for 10Mbit ethernet and HZ=100 the minimal allowed B is ~10Kbytes.
90
91 Note that the peak rate TBF is much more tough: with MTU 1500
92 P_crit = 150Kbytes/sec. So, if you need greater peak
93 rates, use alpha with HZ=1000 :-)
94
95 With classful TBF, limit is just kept for backwards compatibility.
96 It is passed to the default bfifo qdisc - if the inner qdisc is
97 changed the limit is not effective anymore.
98*/
99
100struct tbf_sched_data
101{
102/* Parameters */
103 u32 limit; /* Maximal length of backlog: bytes */
104 u32 buffer; /* Token bucket depth/rate: MUST BE >= MTU/B */
105 u32 mtu;
106 u32 max_size;
107 struct qdisc_rate_table *R_tab;
108 struct qdisc_rate_table *P_tab;
109
110/* Variables */
111 long tokens; /* Current number of B tokens */
112 long ptokens; /* Current number of P tokens */
113 psched_time_t t_c; /* Time check-point */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114 struct Qdisc *qdisc; /* Inner qdisc, default - bfifo queue */
Patrick McHardyf7f593e2007-03-16 01:20:07 -0700115 struct qdisc_watchdog watchdog; /* Watchdog timer */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116};
117
Jesper Dangaard Brouere9bef552007-09-12 16:35:24 +0200118#define L2T(q,L) qdisc_l2t((q)->R_tab,L)
119#define L2T_P(q,L) qdisc_l2t((q)->P_tab,L)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120
121static int tbf_enqueue(struct sk_buff *skb, struct Qdisc* sch)
122{
123 struct tbf_sched_data *q = qdisc_priv(sch);
124 int ret;
125
126 if (skb->len > q->max_size) {
127 sch->qstats.drops++;
Patrick McHardyc3bc7cf2007-07-15 00:03:05 -0700128#ifdef CONFIG_NET_CLS_ACT
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129 if (sch->reshape_fail == NULL || sch->reshape_fail(skb, sch))
130#endif
131 kfree_skb(skb);
132
133 return NET_XMIT_DROP;
134 }
135
136 if ((ret = q->qdisc->enqueue(skb, q->qdisc)) != 0) {
137 sch->qstats.drops++;
138 return ret;
139 }
140
141 sch->q.qlen++;
142 sch->bstats.bytes += skb->len;
143 sch->bstats.packets++;
144 return 0;
145}
146
147static int tbf_requeue(struct sk_buff *skb, struct Qdisc* sch)
148{
149 struct tbf_sched_data *q = qdisc_priv(sch);
150 int ret;
151
152 if ((ret = q->qdisc->ops->requeue(skb, q->qdisc)) == 0) {
153 sch->q.qlen++;
154 sch->qstats.requeues++;
155 }
156
157 return ret;
158}
159
160static unsigned int tbf_drop(struct Qdisc* sch)
161{
162 struct tbf_sched_data *q = qdisc_priv(sch);
Patrick McHardy6d037a22006-03-20 19:00:49 -0800163 unsigned int len = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164
Patrick McHardy6d037a22006-03-20 19:00:49 -0800165 if (q->qdisc->ops->drop && (len = q->qdisc->ops->drop(q->qdisc)) != 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 sch->q.qlen--;
167 sch->qstats.drops++;
168 }
169 return len;
170}
171
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172static struct sk_buff *tbf_dequeue(struct Qdisc* sch)
173{
174 struct tbf_sched_data *q = qdisc_priv(sch);
175 struct sk_buff *skb;
176
177 skb = q->qdisc->dequeue(q->qdisc);
178
179 if (skb) {
180 psched_time_t now;
Patrick McHardyf7f593e2007-03-16 01:20:07 -0700181 long toks;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182 long ptoks = 0;
183 unsigned int len = skb->len;
184
Patrick McHardy3bebcda2007-03-23 11:29:25 -0700185 now = psched_get_time();
Patrick McHardy03cc45c2007-03-23 11:29:11 -0700186 toks = psched_tdiff_bounded(now, q->t_c, q->buffer);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187
188 if (q->P_tab) {
189 ptoks = toks + q->ptokens;
190 if (ptoks > (long)q->mtu)
191 ptoks = q->mtu;
192 ptoks -= L2T_P(q, len);
193 }
194 toks += q->tokens;
195 if (toks > (long)q->buffer)
196 toks = q->buffer;
197 toks -= L2T(q, len);
198
199 if ((toks|ptoks) >= 0) {
200 q->t_c = now;
201 q->tokens = toks;
202 q->ptokens = ptoks;
203 sch->q.qlen--;
204 sch->flags &= ~TCQ_F_THROTTLED;
205 return skb;
206 }
207
Patrick McHardyf7f593e2007-03-16 01:20:07 -0700208 qdisc_watchdog_schedule(&q->watchdog,
209 now + max_t(long, -toks, -ptoks));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210
211 /* Maybe we have a shorter packet in the queue,
212 which can be sent now. It sounds cool,
213 but, however, this is wrong in principle.
214 We MUST NOT reorder packets under these circumstances.
215
216 Really, if we split the flow into independent
217 subflows, it would be a very good solution.
218 This is the main idea of all FQ algorithms
219 (cf. CSZ, HPFQ, HFSC)
220 */
221
222 if (q->qdisc->ops->requeue(skb, q->qdisc) != NET_XMIT_SUCCESS) {
223 /* When requeue fails skb is dropped */
Patrick McHardye488eaf2006-11-29 17:37:42 -0800224 qdisc_tree_decrease_qlen(q->qdisc, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225 sch->qstats.drops++;
226 }
227
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228 sch->qstats.overlimits++;
229 }
230 return NULL;
231}
232
233static void tbf_reset(struct Qdisc* sch)
234{
235 struct tbf_sched_data *q = qdisc_priv(sch);
236
237 qdisc_reset(q->qdisc);
238 sch->q.qlen = 0;
Patrick McHardy3bebcda2007-03-23 11:29:25 -0700239 q->t_c = psched_get_time();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240 q->tokens = q->buffer;
241 q->ptokens = q->mtu;
Patrick McHardyf7f593e2007-03-16 01:20:07 -0700242 qdisc_watchdog_cancel(&q->watchdog);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243}
244
Patrick McHardy9f9afec2006-11-29 17:35:18 -0800245static struct Qdisc *tbf_create_dflt_qdisc(struct Qdisc *sch, u32 limit)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246{
Patrick McHardy9f9afec2006-11-29 17:35:18 -0800247 struct Qdisc *q;
Patrick McHardy1e904742008-01-22 22:11:17 -0800248 struct nlattr *nla;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249 int ret;
250
Patrick McHardy9f9afec2006-11-29 17:35:18 -0800251 q = qdisc_create_dflt(sch->dev, &bfifo_qdisc_ops,
252 TC_H_MAKE(sch->handle, 1));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253 if (q) {
Patrick McHardy1e904742008-01-22 22:11:17 -0800254 nla = kmalloc(nla_attr_size(sizeof(struct tc_fifo_qopt)),
255 GFP_KERNEL);
256 if (nla) {
257 nla->nla_type = RTM_NEWQDISC;
258 nla->nla_len = nla_attr_size(sizeof(struct tc_fifo_qopt));
259 ((struct tc_fifo_qopt *)nla_data(nla))->limit = limit;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260
Patrick McHardy1e904742008-01-22 22:11:17 -0800261 ret = q->ops->change(q, nla);
262 kfree(nla);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263
264 if (ret == 0)
265 return q;
266 }
267 qdisc_destroy(q);
268 }
269
270 return NULL;
271}
272
Patrick McHardy1e904742008-01-22 22:11:17 -0800273static int tbf_change(struct Qdisc* sch, struct nlattr *opt)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274{
275 int err = -EINVAL;
276 struct tbf_sched_data *q = qdisc_priv(sch);
Patrick McHardy1e904742008-01-22 22:11:17 -0800277 struct nlattr *tb[TCA_TBF_PTAB + 1];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278 struct tc_tbf_qopt *qopt;
279 struct qdisc_rate_table *rtab = NULL;
280 struct qdisc_rate_table *ptab = NULL;
281 struct Qdisc *child = NULL;
282 int max_size,n;
283
Patrick McHardy1e904742008-01-22 22:11:17 -0800284 if (nla_parse_nested(tb, TCA_TBF_PTAB, opt, NULL) ||
285 tb[TCA_TBF_PARMS] == NULL ||
286 nla_len(tb[TCA_TBF_PARMS]) < sizeof(*qopt))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 goto done;
288
Patrick McHardy1e904742008-01-22 22:11:17 -0800289 qopt = nla_data(tb[TCA_TBF_PARMS]);
290 rtab = qdisc_get_rtab(&qopt->rate, tb[TCA_TBF_RTAB]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291 if (rtab == NULL)
292 goto done;
293
294 if (qopt->peakrate.rate) {
295 if (qopt->peakrate.rate > qopt->rate.rate)
Patrick McHardy1e904742008-01-22 22:11:17 -0800296 ptab = qdisc_get_rtab(&qopt->peakrate, tb[TCA_TBF_PTAB]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297 if (ptab == NULL)
298 goto done;
299 }
300
301 for (n = 0; n < 256; n++)
302 if (rtab->data[n] > qopt->buffer) break;
303 max_size = (n << qopt->rate.cell_log)-1;
304 if (ptab) {
305 int size;
306
307 for (n = 0; n < 256; n++)
308 if (ptab->data[n] > qopt->mtu) break;
309 size = (n << qopt->peakrate.cell_log)-1;
310 if (size < max_size) max_size = size;
311 }
312 if (max_size < 0)
313 goto done;
314
Patrick McHardy053cfed2006-03-20 19:01:21 -0800315 if (qopt->limit > 0) {
Patrick McHardy9f9afec2006-11-29 17:35:18 -0800316 if ((child = tbf_create_dflt_qdisc(sch, qopt->limit)) == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317 goto done;
318 }
319
320 sch_tree_lock(sch);
Patrick McHardy5e50da02006-11-29 17:36:20 -0800321 if (child) {
322 qdisc_tree_decrease_qlen(q->qdisc, q->qdisc->q.qlen);
Patrick McHardy053cfed2006-03-20 19:01:21 -0800323 qdisc_destroy(xchg(&q->qdisc, child));
Patrick McHardy5e50da02006-11-29 17:36:20 -0800324 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325 q->limit = qopt->limit;
326 q->mtu = qopt->mtu;
327 q->max_size = max_size;
328 q->buffer = qopt->buffer;
329 q->tokens = q->buffer;
330 q->ptokens = q->mtu;
331 rtab = xchg(&q->R_tab, rtab);
332 ptab = xchg(&q->P_tab, ptab);
333 sch_tree_unlock(sch);
334 err = 0;
335done:
336 if (rtab)
337 qdisc_put_rtab(rtab);
338 if (ptab)
339 qdisc_put_rtab(ptab);
340 return err;
341}
342
Patrick McHardy1e904742008-01-22 22:11:17 -0800343static int tbf_init(struct Qdisc* sch, struct nlattr *opt)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344{
345 struct tbf_sched_data *q = qdisc_priv(sch);
346
347 if (opt == NULL)
348 return -EINVAL;
349
Patrick McHardy3bebcda2007-03-23 11:29:25 -0700350 q->t_c = psched_get_time();
Patrick McHardyf7f593e2007-03-16 01:20:07 -0700351 qdisc_watchdog_init(&q->watchdog, sch);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700352 q->qdisc = &noop_qdisc;
353
354 return tbf_change(sch, opt);
355}
356
357static void tbf_destroy(struct Qdisc *sch)
358{
359 struct tbf_sched_data *q = qdisc_priv(sch);
360
Patrick McHardyf7f593e2007-03-16 01:20:07 -0700361 qdisc_watchdog_cancel(&q->watchdog);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362
363 if (q->P_tab)
364 qdisc_put_rtab(q->P_tab);
365 if (q->R_tab)
366 qdisc_put_rtab(q->R_tab);
367
368 qdisc_destroy(q->qdisc);
369}
370
371static int tbf_dump(struct Qdisc *sch, struct sk_buff *skb)
372{
373 struct tbf_sched_data *q = qdisc_priv(sch);
Arnaldo Carvalho de Melo27a884d2007-04-19 20:29:13 -0700374 unsigned char *b = skb_tail_pointer(skb);
Patrick McHardy1e904742008-01-22 22:11:17 -0800375 struct nlattr *nla;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700376 struct tc_tbf_qopt opt;
377
Patrick McHardy1e904742008-01-22 22:11:17 -0800378 nla = (struct nlattr*)b;
379 NLA_PUT(skb, TCA_OPTIONS, 0, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380
381 opt.limit = q->limit;
382 opt.rate = q->R_tab->rate;
383 if (q->P_tab)
384 opt.peakrate = q->P_tab->rate;
385 else
386 memset(&opt.peakrate, 0, sizeof(opt.peakrate));
387 opt.mtu = q->mtu;
388 opt.buffer = q->buffer;
Patrick McHardy1e904742008-01-22 22:11:17 -0800389 NLA_PUT(skb, TCA_TBF_PARMS, sizeof(opt), &opt);
390 nla->nla_len = skb_tail_pointer(skb) - b;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700391
392 return skb->len;
393
Patrick McHardy1e904742008-01-22 22:11:17 -0800394nla_put_failure:
Arnaldo Carvalho de Melodc5fc572007-03-25 23:06:12 -0700395 nlmsg_trim(skb, b);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700396 return -1;
397}
398
399static int tbf_dump_class(struct Qdisc *sch, unsigned long cl,
400 struct sk_buff *skb, struct tcmsg *tcm)
401{
402 struct tbf_sched_data *q = qdisc_priv(sch);
403
404 if (cl != 1) /* only one class */
405 return -ENOENT;
406
407 tcm->tcm_handle |= TC_H_MIN(1);
408 tcm->tcm_info = q->qdisc->handle;
409
410 return 0;
411}
412
413static int tbf_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
414 struct Qdisc **old)
415{
416 struct tbf_sched_data *q = qdisc_priv(sch);
417
418 if (new == NULL)
419 new = &noop_qdisc;
420
421 sch_tree_lock(sch);
422 *old = xchg(&q->qdisc, new);
Patrick McHardy5e50da02006-11-29 17:36:20 -0800423 qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424 qdisc_reset(*old);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425 sch_tree_unlock(sch);
426
427 return 0;
428}
429
430static struct Qdisc *tbf_leaf(struct Qdisc *sch, unsigned long arg)
431{
432 struct tbf_sched_data *q = qdisc_priv(sch);
433 return q->qdisc;
434}
435
436static unsigned long tbf_get(struct Qdisc *sch, u32 classid)
437{
438 return 1;
439}
440
441static void tbf_put(struct Qdisc *sch, unsigned long arg)
442{
443}
444
YOSHIFUJI Hideaki10297b92007-02-09 23:25:16 +0900445static int tbf_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
Patrick McHardy1e904742008-01-22 22:11:17 -0800446 struct nlattr **tca, unsigned long *arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447{
448 return -ENOSYS;
449}
450
451static int tbf_delete(struct Qdisc *sch, unsigned long arg)
452{
453 return -ENOSYS;
454}
455
456static void tbf_walk(struct Qdisc *sch, struct qdisc_walker *walker)
457{
458 if (!walker->stop) {
459 if (walker->count >= walker->skip)
460 if (walker->fn(sch, 1, walker) < 0) {
461 walker->stop = 1;
462 return;
463 }
464 walker->count++;
465 }
466}
467
468static struct tcf_proto **tbf_find_tcf(struct Qdisc *sch, unsigned long cl)
469{
470 return NULL;
471}
472
Eric Dumazet20fea082007-11-14 01:44:41 -0800473static const struct Qdisc_class_ops tbf_class_ops =
Linus Torvalds1da177e2005-04-16 15:20:36 -0700474{
475 .graft = tbf_graft,
476 .leaf = tbf_leaf,
477 .get = tbf_get,
478 .put = tbf_put,
479 .change = tbf_change_class,
480 .delete = tbf_delete,
481 .walk = tbf_walk,
482 .tcf_chain = tbf_find_tcf,
483 .dump = tbf_dump_class,
484};
485
Eric Dumazet20fea082007-11-14 01:44:41 -0800486static struct Qdisc_ops tbf_qdisc_ops __read_mostly = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700487 .next = NULL,
488 .cl_ops = &tbf_class_ops,
489 .id = "tbf",
490 .priv_size = sizeof(struct tbf_sched_data),
491 .enqueue = tbf_enqueue,
492 .dequeue = tbf_dequeue,
493 .requeue = tbf_requeue,
494 .drop = tbf_drop,
495 .init = tbf_init,
496 .reset = tbf_reset,
497 .destroy = tbf_destroy,
498 .change = tbf_change,
499 .dump = tbf_dump,
500 .owner = THIS_MODULE,
501};
502
503static int __init tbf_module_init(void)
504{
505 return register_qdisc(&tbf_qdisc_ops);
506}
507
508static void __exit tbf_module_exit(void)
509{
510 unregister_qdisc(&tbf_qdisc_ops);
511}
512module_init(tbf_module_init)
513module_exit(tbf_module_exit)
514MODULE_LICENSE("GPL");