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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
15#include <linux/module.h>
16#include <linux/types.h>
17#include <linux/kernel.h>
18#include <linux/string.h>
19#include <linux/errno.h>
20#include <linux/skbuff.h>
21#include <net/netlink.h>
22#include <net/sch_generic.h>
23#include <net/pkt_sched.h>
24
25
26/* Simple Token Bucket Filter.
27 =======================================
28
29 SOURCE.
30 -------
31
32 None.
33
34 Description.
35 ------------
36
37 A data flow obeys TBF with rate R and depth B, if for any
38 time interval t_i...t_f the number of transmitted bits
39 does not exceed B + R*(t_f-t_i).
40
41 Packetized version of this definition:
42 The sequence of packets of sizes s_i served at moments t_i
43 obeys TBF, if for any i<=k:
44
45 s_i+....+s_k <= B + R*(t_k - t_i)
46
47 Algorithm.
48 ----------
49
50 Let N(t_i) be B/R initially and N(t) grow continuously with time as:
51
52 N(t+delta) = min{B/R, N(t) + delta}
53
54 If the first packet in queue has length S, it may be
55 transmitted only at the time t_* when S/R <= N(t_*),
56 and in this case N(t) jumps:
57
58 N(t_* + 0) = N(t_* - 0) - S/R.
59
60
61
62 Actually, QoS requires two TBF to be applied to a data stream.
63 One of them controls steady state burst size, another
64 one with rate P (peak rate) and depth M (equal to link MTU)
65 limits bursts at a smaller time scale.
66
67 It is easy to see that P>R, and B>M. If P is infinity, this double
68 TBF is equivalent to a single one.
69
70 When TBF works in reshaping mode, latency is estimated as:
71
72 lat = max ((L-B)/R, (L-M)/P)
73
74
75 NOTES.
76 ------
77
78 If TBF throttles, it starts a watchdog timer, which will wake it up
79 when it is ready to transmit.
80 Note that the minimal timer resolution is 1/HZ.
81 If no new packets arrive during this period,
82 or if the device is not awaken by EOI for some previous packet,
83 TBF can stop its activity for 1/HZ.
84
85
86 This means, that with depth B, the maximal rate is
87
88 R_crit = B*HZ
89
90 F.e. for 10Mbit ethernet and HZ=100 the minimal allowed B is ~10Kbytes.
91
92 Note that the peak rate TBF is much more tough: with MTU 1500
93 P_crit = 150Kbytes/sec. So, if you need greater peak
94 rates, use alpha with HZ=1000 :-)
95
96 With classful TBF, limit is just kept for backwards compatibility.
97 It is passed to the default bfifo qdisc - if the inner qdisc is
98 changed the limit is not effective anymore.
99*/
100
101struct tbf_sched_data {
102/* Parameters */
103 u32 limit; /* Maximal length of backlog: bytes */
104 u32 max_size;
105 s64 buffer; /* Token bucket depth/rate: MUST BE >= MTU/B */
106 s64 mtu;
107 struct psched_ratecfg rate;
108 struct psched_ratecfg peak;
109
110/* Variables */
111 s64 tokens; /* Current number of B tokens */
112 s64 ptokens; /* Current number of P tokens */
113 s64 t_c; /* Time check-point */
114 struct Qdisc *qdisc; /* Inner qdisc, default - bfifo queue */
115 struct qdisc_watchdog watchdog; /* Watchdog timer */
116};
117
118
119/* Time to Length, convert time in ns to length in bytes
120 * to determinate how many bytes can be sent in given time.
121 */
122static u64 psched_ns_t2l(const struct psched_ratecfg *r,
123 u64 time_in_ns)
124{
125 /* The formula is :
126 * len = (time_in_ns * r->rate_bytes_ps) / NSEC_PER_SEC
127 */
128 u64 len = time_in_ns * r->rate_bytes_ps;
129
130 do_div(len, NSEC_PER_SEC);
131
132 if (unlikely(r->linklayer == TC_LINKLAYER_ATM)) {
133 do_div(len, 53);
134 len = len * 48;
135 }
136
137 if (len > r->overhead)
138 len -= r->overhead;
139 else
140 len = 0;
141
142 return len;
143}
144
145/*
146 * Return length of individual segments of a gso packet,
147 * including all headers (MAC, IP, TCP/UDP)
148 */
149static unsigned int skb_gso_mac_seglen(const struct sk_buff *skb)
150{
151 unsigned int hdr_len = skb_transport_header(skb) - skb_mac_header(skb);
152 return hdr_len + skb_gso_transport_seglen(skb);
153}
154
155/* GSO packet is too big, segment it so that tbf can transmit
156 * each segment in time
157 */
158static int tbf_segment(struct sk_buff *skb, struct Qdisc *sch)
159{
160 struct tbf_sched_data *q = qdisc_priv(sch);
161 struct sk_buff *segs, *nskb;
162 netdev_features_t features = netif_skb_features(skb);
163 int ret, nb;
164
165 segs = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK);
166
167 if (IS_ERR_OR_NULL(segs))
168 return qdisc_reshape_fail(skb, sch);
169
170 nb = 0;
171 while (segs) {
172 nskb = segs->next;
173 segs->next = NULL;
174 qdisc_skb_cb(segs)->pkt_len = segs->len;
175 ret = qdisc_enqueue(segs, q->qdisc);
176 if (ret != NET_XMIT_SUCCESS) {
177 if (net_xmit_drop_count(ret))
178 sch->qstats.drops++;
179 } else {
180 nb++;
181 }
182 segs = nskb;
183 }
184 sch->q.qlen += nb;
185 if (nb > 1)
186 qdisc_tree_decrease_qlen(sch, 1 - nb);
187 consume_skb(skb);
188 return nb > 0 ? NET_XMIT_SUCCESS : NET_XMIT_DROP;
189}
190
191static int tbf_enqueue(struct sk_buff *skb, struct Qdisc *sch)
192{
193 struct tbf_sched_data *q = qdisc_priv(sch);
194 int ret;
195
196 if (qdisc_pkt_len(skb) > q->max_size) {
197 if (skb_is_gso(skb) && skb_gso_mac_seglen(skb) <= q->max_size)
198 return tbf_segment(skb, sch);
199 return qdisc_reshape_fail(skb, sch);
200 }
201 ret = qdisc_enqueue(skb, q->qdisc);
202 if (ret != NET_XMIT_SUCCESS) {
203 if (net_xmit_drop_count(ret))
204 sch->qstats.drops++;
205 return ret;
206 }
207
208 sch->q.qlen++;
209 return NET_XMIT_SUCCESS;
210}
211
212static unsigned int tbf_drop(struct Qdisc *sch)
213{
214 struct tbf_sched_data *q = qdisc_priv(sch);
215 unsigned int len = 0;
216
217 if (q->qdisc->ops->drop && (len = q->qdisc->ops->drop(q->qdisc)) != 0) {
218 sch->q.qlen--;
219 sch->qstats.drops++;
220 }
221 return len;
222}
223
224static bool tbf_peak_present(const struct tbf_sched_data *q)
225{
226 return q->peak.rate_bytes_ps;
227}
228
229static struct sk_buff *tbf_dequeue(struct Qdisc *sch)
230{
231 struct tbf_sched_data *q = qdisc_priv(sch);
232 struct sk_buff *skb;
233
234 skb = q->qdisc->ops->peek(q->qdisc);
235
236 if (skb) {
237 s64 now;
238 s64 toks;
239 s64 ptoks = 0;
240 unsigned int len = qdisc_pkt_len(skb);
241
242 now = ktime_to_ns(ktime_get());
243 toks = min_t(s64, now - q->t_c, q->buffer);
244
245 if (tbf_peak_present(q)) {
246 ptoks = toks + q->ptokens;
247 if (ptoks > q->mtu)
248 ptoks = q->mtu;
249 ptoks -= (s64) psched_l2t_ns(&q->peak, len);
250 }
251 toks += q->tokens;
252 if (toks > q->buffer)
253 toks = q->buffer;
254 toks -= (s64) psched_l2t_ns(&q->rate, len);
255
256 if ((toks|ptoks) >= 0) {
257 skb = qdisc_dequeue_peeked(q->qdisc);
258 if (unlikely(!skb))
259 return NULL;
260
261 q->t_c = now;
262 q->tokens = toks;
263 q->ptokens = ptoks;
264 sch->q.qlen--;
265 qdisc_unthrottled(sch);
266 qdisc_bstats_update(sch, skb);
267 return skb;
268 }
269
270 qdisc_watchdog_schedule_ns(&q->watchdog,
271 now + max_t(long, -toks, -ptoks));
272
273 /* Maybe we have a shorter packet in the queue,
274 which can be sent now. It sounds cool,
275 but, however, this is wrong in principle.
276 We MUST NOT reorder packets under these circumstances.
277
278 Really, if we split the flow into independent
279 subflows, it would be a very good solution.
280 This is the main idea of all FQ algorithms
281 (cf. CSZ, HPFQ, HFSC)
282 */
283
284 sch->qstats.overlimits++;
285 }
286 return NULL;
287}
288
289static void tbf_reset(struct Qdisc *sch)
290{
291 struct tbf_sched_data *q = qdisc_priv(sch);
292
293 qdisc_reset(q->qdisc);
294 sch->q.qlen = 0;
295 q->t_c = ktime_to_ns(ktime_get());
296 q->tokens = q->buffer;
297 q->ptokens = q->mtu;
298 qdisc_watchdog_cancel(&q->watchdog);
299}
300
301static const struct nla_policy tbf_policy[TCA_TBF_MAX + 1] = {
302 [TCA_TBF_PARMS] = { .len = sizeof(struct tc_tbf_qopt) },
303 [TCA_TBF_RTAB] = { .type = NLA_BINARY, .len = TC_RTAB_SIZE },
304 [TCA_TBF_PTAB] = { .type = NLA_BINARY, .len = TC_RTAB_SIZE },
305 [TCA_TBF_RATE64] = { .type = NLA_U64 },
306 [TCA_TBF_PRATE64] = { .type = NLA_U64 },
307 [TCA_TBF_BURST] = { .type = NLA_U32 },
308 [TCA_TBF_PBURST] = { .type = NLA_U32 },
309};
310
311static int tbf_change(struct Qdisc *sch, struct nlattr *opt)
312{
313 int err;
314 struct tbf_sched_data *q = qdisc_priv(sch);
315 struct nlattr *tb[TCA_TBF_MAX + 1];
316 struct tc_tbf_qopt *qopt;
317 struct Qdisc *child = NULL;
318 struct psched_ratecfg rate;
319 struct psched_ratecfg peak;
320 u64 max_size;
321 s64 buffer, mtu;
322 u64 rate64 = 0, prate64 = 0;
323
324 err = nla_parse_nested(tb, TCA_TBF_MAX, opt, tbf_policy);
325 if (err < 0)
326 return err;
327
328 err = -EINVAL;
329 if (tb[TCA_TBF_PARMS] == NULL)
330 goto done;
331
332 qopt = nla_data(tb[TCA_TBF_PARMS]);
333 if (qopt->rate.linklayer == TC_LINKLAYER_UNAWARE)
334 qdisc_put_rtab(qdisc_get_rtab(&qopt->rate,
335 tb[TCA_TBF_RTAB]));
336
337 if (qopt->peakrate.linklayer == TC_LINKLAYER_UNAWARE)
338 qdisc_put_rtab(qdisc_get_rtab(&qopt->peakrate,
339 tb[TCA_TBF_PTAB]));
340
341 buffer = min_t(u64, PSCHED_TICKS2NS(qopt->buffer), ~0U);
342 mtu = min_t(u64, PSCHED_TICKS2NS(qopt->mtu), ~0U);
343
344 if (tb[TCA_TBF_RATE64])
345 rate64 = nla_get_u64(tb[TCA_TBF_RATE64]);
346 psched_ratecfg_precompute(&rate, &qopt->rate, rate64);
347
348 if (tb[TCA_TBF_BURST]) {
349 max_size = nla_get_u32(tb[TCA_TBF_BURST]);
350 buffer = psched_l2t_ns(&rate, max_size);
351 } else {
352 max_size = min_t(u64, psched_ns_t2l(&rate, buffer), ~0U);
353 }
354
355 if (qopt->peakrate.rate) {
356 if (tb[TCA_TBF_PRATE64])
357 prate64 = nla_get_u64(tb[TCA_TBF_PRATE64]);
358 psched_ratecfg_precompute(&peak, &qopt->peakrate, prate64);
359 if (peak.rate_bytes_ps <= rate.rate_bytes_ps) {
360 pr_warn_ratelimited("sch_tbf: peakrate %llu is lower than or equals to rate %llu !\n",
361 peak.rate_bytes_ps, rate.rate_bytes_ps);
362 err = -EINVAL;
363 goto done;
364 }
365
366 if (tb[TCA_TBF_PBURST]) {
367 u32 pburst = nla_get_u32(tb[TCA_TBF_PBURST]);
368 max_size = min_t(u32, max_size, pburst);
369 mtu = psched_l2t_ns(&peak, pburst);
370 } else {
371 max_size = min_t(u64, max_size, psched_ns_t2l(&peak, mtu));
372 }
373 } else {
374 memset(&peak, 0, sizeof(peak));
375 }
376
377 if (max_size < psched_mtu(qdisc_dev(sch)))
378 pr_warn_ratelimited("sch_tbf: burst %llu is lower than device %s mtu (%u) !\n",
379 max_size, qdisc_dev(sch)->name,
380 psched_mtu(qdisc_dev(sch)));
381
382 if (!max_size) {
383 err = -EINVAL;
384 goto done;
385 }
386
387 if (q->qdisc != &noop_qdisc) {
388 err = fifo_set_limit(q->qdisc, qopt->limit);
389 if (err)
390 goto done;
391 } else if (qopt->limit > 0) {
392 child = fifo_create_dflt(sch, &bfifo_qdisc_ops, qopt->limit);
393 if (IS_ERR(child)) {
394 err = PTR_ERR(child);
395 goto done;
396 }
397 }
398
399 sch_tree_lock(sch);
400 if (child) {
401 qdisc_tree_decrease_qlen(q->qdisc, q->qdisc->q.qlen);
402 qdisc_destroy(q->qdisc);
403 q->qdisc = child;
404 }
405 q->limit = qopt->limit;
406 if (tb[TCA_TBF_PBURST])
407 q->mtu = mtu;
408 else
409 q->mtu = PSCHED_TICKS2NS(qopt->mtu);
410 q->max_size = max_size;
411 if (tb[TCA_TBF_BURST])
412 q->buffer = buffer;
413 else
414 q->buffer = PSCHED_TICKS2NS(qopt->buffer);
415 q->tokens = q->buffer;
416 q->ptokens = q->mtu;
417
418 memcpy(&q->rate, &rate, sizeof(struct psched_ratecfg));
419 memcpy(&q->peak, &peak, sizeof(struct psched_ratecfg));
420
421 sch_tree_unlock(sch);
422 err = 0;
423done:
424 return err;
425}
426
427static int tbf_init(struct Qdisc *sch, struct nlattr *opt)
428{
429 struct tbf_sched_data *q = qdisc_priv(sch);
430
431 if (opt == NULL)
432 return -EINVAL;
433
434 q->t_c = ktime_to_ns(ktime_get());
435 qdisc_watchdog_init(&q->watchdog, sch);
436 q->qdisc = &noop_qdisc;
437
438 return tbf_change(sch, opt);
439}
440
441static void tbf_destroy(struct Qdisc *sch)
442{
443 struct tbf_sched_data *q = qdisc_priv(sch);
444
445 qdisc_watchdog_cancel(&q->watchdog);
446 qdisc_destroy(q->qdisc);
447}
448
449static int tbf_dump(struct Qdisc *sch, struct sk_buff *skb)
450{
451 struct tbf_sched_data *q = qdisc_priv(sch);
452 struct nlattr *nest;
453 struct tc_tbf_qopt opt;
454
455 sch->qstats.backlog = q->qdisc->qstats.backlog;
456 nest = nla_nest_start(skb, TCA_OPTIONS);
457 if (nest == NULL)
458 goto nla_put_failure;
459
460 opt.limit = q->limit;
461 psched_ratecfg_getrate(&opt.rate, &q->rate);
462 if (tbf_peak_present(q))
463 psched_ratecfg_getrate(&opt.peakrate, &q->peak);
464 else
465 memset(&opt.peakrate, 0, sizeof(opt.peakrate));
466 opt.mtu = PSCHED_NS2TICKS(q->mtu);
467 opt.buffer = PSCHED_NS2TICKS(q->buffer);
468 if (nla_put(skb, TCA_TBF_PARMS, sizeof(opt), &opt))
469 goto nla_put_failure;
470 if (q->rate.rate_bytes_ps >= (1ULL << 32) &&
471 nla_put_u64(skb, TCA_TBF_RATE64, q->rate.rate_bytes_ps))
472 goto nla_put_failure;
473 if (tbf_peak_present(q) &&
474 q->peak.rate_bytes_ps >= (1ULL << 32) &&
475 nla_put_u64(skb, TCA_TBF_PRATE64, q->peak.rate_bytes_ps))
476 goto nla_put_failure;
477
478 return nla_nest_end(skb, nest);
479
480nla_put_failure:
481 nla_nest_cancel(skb, nest);
482 return -1;
483}
484
485static int tbf_dump_class(struct Qdisc *sch, unsigned long cl,
486 struct sk_buff *skb, struct tcmsg *tcm)
487{
488 struct tbf_sched_data *q = qdisc_priv(sch);
489
490 tcm->tcm_handle |= TC_H_MIN(1);
491 tcm->tcm_info = q->qdisc->handle;
492
493 return 0;
494}
495
496static int tbf_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
497 struct Qdisc **old)
498{
499 struct tbf_sched_data *q = qdisc_priv(sch);
500
501 if (new == NULL)
502 new = &noop_qdisc;
503
504 sch_tree_lock(sch);
505 *old = q->qdisc;
506 q->qdisc = new;
507 qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
508 qdisc_reset(*old);
509 sch_tree_unlock(sch);
510
511 return 0;
512}
513
514static struct Qdisc *tbf_leaf(struct Qdisc *sch, unsigned long arg)
515{
516 struct tbf_sched_data *q = qdisc_priv(sch);
517 return q->qdisc;
518}
519
520static unsigned long tbf_get(struct Qdisc *sch, u32 classid)
521{
522 return 1;
523}
524
525static void tbf_put(struct Qdisc *sch, unsigned long arg)
526{
527}
528
529static void tbf_walk(struct Qdisc *sch, struct qdisc_walker *walker)
530{
531 if (!walker->stop) {
532 if (walker->count >= walker->skip)
533 if (walker->fn(sch, 1, walker) < 0) {
534 walker->stop = 1;
535 return;
536 }
537 walker->count++;
538 }
539}
540
541static const struct Qdisc_class_ops tbf_class_ops = {
542 .graft = tbf_graft,
543 .leaf = tbf_leaf,
544 .get = tbf_get,
545 .put = tbf_put,
546 .walk = tbf_walk,
547 .dump = tbf_dump_class,
548};
549
550static struct Qdisc_ops tbf_qdisc_ops __read_mostly = {
551 .next = NULL,
552 .cl_ops = &tbf_class_ops,
553 .id = "tbf",
554 .priv_size = sizeof(struct tbf_sched_data),
555 .enqueue = tbf_enqueue,
556 .dequeue = tbf_dequeue,
557 .peek = qdisc_peek_dequeued,
558 .drop = tbf_drop,
559 .init = tbf_init,
560 .reset = tbf_reset,
561 .destroy = tbf_destroy,
562 .change = tbf_change,
563 .dump = tbf_dump,
564 .owner = THIS_MODULE,
565};
566
567static int __init tbf_module_init(void)
568{
569 return register_qdisc(&tbf_qdisc_ops);
570}
571
572static void __exit tbf_module_exit(void)
573{
574 unregister_qdisc(&tbf_qdisc_ops);
575}
576module_init(tbf_module_init)
577module_exit(tbf_module_exit)
578MODULE_LICENSE("GPL");
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * net/sched/sch_tbf.c Token Bucket Filter queue.
4 *
5 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
6 * Dmitry Torokhov <dtor@mail.ru> - allow attaching inner qdiscs -
7 * original idea by Martin Devera
8 */
9
10#include <linux/module.h>
11#include <linux/types.h>
12#include <linux/kernel.h>
13#include <linux/string.h>
14#include <linux/errno.h>
15#include <linux/skbuff.h>
16#include <net/netlink.h>
17#include <net/sch_generic.h>
18#include <net/pkt_cls.h>
19#include <net/pkt_sched.h>
20
21
22/* Simple Token Bucket Filter.
23 =======================================
24
25 SOURCE.
26 -------
27
28 None.
29
30 Description.
31 ------------
32
33 A data flow obeys TBF with rate R and depth B, if for any
34 time interval t_i...t_f the number of transmitted bits
35 does not exceed B + R*(t_f-t_i).
36
37 Packetized version of this definition:
38 The sequence of packets of sizes s_i served at moments t_i
39 obeys TBF, if for any i<=k:
40
41 s_i+....+s_k <= B + R*(t_k - t_i)
42
43 Algorithm.
44 ----------
45
46 Let N(t_i) be B/R initially and N(t) grow continuously with time as:
47
48 N(t+delta) = min{B/R, N(t) + delta}
49
50 If the first packet in queue has length S, it may be
51 transmitted only at the time t_* when S/R <= N(t_*),
52 and in this case N(t) jumps:
53
54 N(t_* + 0) = N(t_* - 0) - S/R.
55
56
57
58 Actually, QoS requires two TBF to be applied to a data stream.
59 One of them controls steady state burst size, another
60 one with rate P (peak rate) and depth M (equal to link MTU)
61 limits bursts at a smaller time scale.
62
63 It is easy to see that P>R, and B>M. If P is infinity, this double
64 TBF is equivalent to a single one.
65
66 When TBF works in reshaping mode, latency is estimated as:
67
68 lat = max ((L-B)/R, (L-M)/P)
69
70
71 NOTES.
72 ------
73
74 If TBF throttles, it starts a watchdog timer, which will wake it up
75 when it is ready to transmit.
76 Note that the minimal timer resolution is 1/HZ.
77 If no new packets arrive during this period,
78 or if the device is not awaken by EOI for some previous packet,
79 TBF can stop its activity for 1/HZ.
80
81
82 This means, that with depth B, the maximal rate is
83
84 R_crit = B*HZ
85
86 F.e. for 10Mbit ethernet and HZ=100 the minimal allowed B is ~10Kbytes.
87
88 Note that the peak rate TBF is much more tough: with MTU 1500
89 P_crit = 150Kbytes/sec. So, if you need greater peak
90 rates, use alpha with HZ=1000 :-)
91
92 With classful TBF, limit is just kept for backwards compatibility.
93 It is passed to the default bfifo qdisc - if the inner qdisc is
94 changed the limit is not effective anymore.
95*/
96
97struct tbf_sched_data {
98/* Parameters */
99 u32 limit; /* Maximal length of backlog: bytes */
100 u32 max_size;
101 s64 buffer; /* Token bucket depth/rate: MUST BE >= MTU/B */
102 s64 mtu;
103 struct psched_ratecfg rate;
104 struct psched_ratecfg peak;
105
106/* Variables */
107 s64 tokens; /* Current number of B tokens */
108 s64 ptokens; /* Current number of P tokens */
109 s64 t_c; /* Time check-point */
110 struct Qdisc *qdisc; /* Inner qdisc, default - bfifo queue */
111 struct qdisc_watchdog watchdog; /* Watchdog timer */
112};
113
114
115/* Time to Length, convert time in ns to length in bytes
116 * to determinate how many bytes can be sent in given time.
117 */
118static u64 psched_ns_t2l(const struct psched_ratecfg *r,
119 u64 time_in_ns)
120{
121 /* The formula is :
122 * len = (time_in_ns * r->rate_bytes_ps) / NSEC_PER_SEC
123 */
124 u64 len = time_in_ns * r->rate_bytes_ps;
125
126 do_div(len, NSEC_PER_SEC);
127
128 if (unlikely(r->linklayer == TC_LINKLAYER_ATM)) {
129 do_div(len, 53);
130 len = len * 48;
131 }
132
133 if (len > r->overhead)
134 len -= r->overhead;
135 else
136 len = 0;
137
138 return len;
139}
140
141static void tbf_offload_change(struct Qdisc *sch)
142{
143 struct tbf_sched_data *q = qdisc_priv(sch);
144 struct net_device *dev = qdisc_dev(sch);
145 struct tc_tbf_qopt_offload qopt;
146
147 if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
148 return;
149
150 qopt.command = TC_TBF_REPLACE;
151 qopt.handle = sch->handle;
152 qopt.parent = sch->parent;
153 qopt.replace_params.rate = q->rate;
154 qopt.replace_params.max_size = q->max_size;
155 qopt.replace_params.qstats = &sch->qstats;
156
157 dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_TBF, &qopt);
158}
159
160static void tbf_offload_destroy(struct Qdisc *sch)
161{
162 struct net_device *dev = qdisc_dev(sch);
163 struct tc_tbf_qopt_offload qopt;
164
165 if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
166 return;
167
168 qopt.command = TC_TBF_DESTROY;
169 qopt.handle = sch->handle;
170 qopt.parent = sch->parent;
171 dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_TBF, &qopt);
172}
173
174static int tbf_offload_dump(struct Qdisc *sch)
175{
176 struct tc_tbf_qopt_offload qopt;
177
178 qopt.command = TC_TBF_STATS;
179 qopt.handle = sch->handle;
180 qopt.parent = sch->parent;
181 qopt.stats.bstats = &sch->bstats;
182 qopt.stats.qstats = &sch->qstats;
183
184 return qdisc_offload_dump_helper(sch, TC_SETUP_QDISC_TBF, &qopt);
185}
186
187/* GSO packet is too big, segment it so that tbf can transmit
188 * each segment in time
189 */
190static int tbf_segment(struct sk_buff *skb, struct Qdisc *sch,
191 struct sk_buff **to_free)
192{
193 struct tbf_sched_data *q = qdisc_priv(sch);
194 struct sk_buff *segs, *nskb;
195 netdev_features_t features = netif_skb_features(skb);
196 unsigned int len = 0, prev_len = qdisc_pkt_len(skb);
197 int ret, nb;
198
199 segs = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK);
200
201 if (IS_ERR_OR_NULL(segs))
202 return qdisc_drop(skb, sch, to_free);
203
204 nb = 0;
205 skb_list_walk_safe(segs, segs, nskb) {
206 skb_mark_not_on_list(segs);
207 qdisc_skb_cb(segs)->pkt_len = segs->len;
208 len += segs->len;
209 ret = qdisc_enqueue(segs, q->qdisc, to_free);
210 if (ret != NET_XMIT_SUCCESS) {
211 if (net_xmit_drop_count(ret))
212 qdisc_qstats_drop(sch);
213 } else {
214 nb++;
215 }
216 }
217 sch->q.qlen += nb;
218 if (nb > 1)
219 qdisc_tree_reduce_backlog(sch, 1 - nb, prev_len - len);
220 consume_skb(skb);
221 return nb > 0 ? NET_XMIT_SUCCESS : NET_XMIT_DROP;
222}
223
224static int tbf_enqueue(struct sk_buff *skb, struct Qdisc *sch,
225 struct sk_buff **to_free)
226{
227 struct tbf_sched_data *q = qdisc_priv(sch);
228 unsigned int len = qdisc_pkt_len(skb);
229 int ret;
230
231 if (qdisc_pkt_len(skb) > q->max_size) {
232 if (skb_is_gso(skb) &&
233 skb_gso_validate_mac_len(skb, q->max_size))
234 return tbf_segment(skb, sch, to_free);
235 return qdisc_drop(skb, sch, to_free);
236 }
237 ret = qdisc_enqueue(skb, q->qdisc, to_free);
238 if (ret != NET_XMIT_SUCCESS) {
239 if (net_xmit_drop_count(ret))
240 qdisc_qstats_drop(sch);
241 return ret;
242 }
243
244 sch->qstats.backlog += len;
245 sch->q.qlen++;
246 return NET_XMIT_SUCCESS;
247}
248
249static bool tbf_peak_present(const struct tbf_sched_data *q)
250{
251 return q->peak.rate_bytes_ps;
252}
253
254static struct sk_buff *tbf_dequeue(struct Qdisc *sch)
255{
256 struct tbf_sched_data *q = qdisc_priv(sch);
257 struct sk_buff *skb;
258
259 skb = q->qdisc->ops->peek(q->qdisc);
260
261 if (skb) {
262 s64 now;
263 s64 toks;
264 s64 ptoks = 0;
265 unsigned int len = qdisc_pkt_len(skb);
266
267 now = ktime_get_ns();
268 toks = min_t(s64, now - q->t_c, q->buffer);
269
270 if (tbf_peak_present(q)) {
271 ptoks = toks + q->ptokens;
272 if (ptoks > q->mtu)
273 ptoks = q->mtu;
274 ptoks -= (s64) psched_l2t_ns(&q->peak, len);
275 }
276 toks += q->tokens;
277 if (toks > q->buffer)
278 toks = q->buffer;
279 toks -= (s64) psched_l2t_ns(&q->rate, len);
280
281 if ((toks|ptoks) >= 0) {
282 skb = qdisc_dequeue_peeked(q->qdisc);
283 if (unlikely(!skb))
284 return NULL;
285
286 q->t_c = now;
287 q->tokens = toks;
288 q->ptokens = ptoks;
289 qdisc_qstats_backlog_dec(sch, skb);
290 sch->q.qlen--;
291 qdisc_bstats_update(sch, skb);
292 return skb;
293 }
294
295 qdisc_watchdog_schedule_ns(&q->watchdog,
296 now + max_t(long, -toks, -ptoks));
297
298 /* Maybe we have a shorter packet in the queue,
299 which can be sent now. It sounds cool,
300 but, however, this is wrong in principle.
301 We MUST NOT reorder packets under these circumstances.
302
303 Really, if we split the flow into independent
304 subflows, it would be a very good solution.
305 This is the main idea of all FQ algorithms
306 (cf. CSZ, HPFQ, HFSC)
307 */
308
309 qdisc_qstats_overlimit(sch);
310 }
311 return NULL;
312}
313
314static void tbf_reset(struct Qdisc *sch)
315{
316 struct tbf_sched_data *q = qdisc_priv(sch);
317
318 qdisc_reset(q->qdisc);
319 sch->qstats.backlog = 0;
320 sch->q.qlen = 0;
321 q->t_c = ktime_get_ns();
322 q->tokens = q->buffer;
323 q->ptokens = q->mtu;
324 qdisc_watchdog_cancel(&q->watchdog);
325}
326
327static const struct nla_policy tbf_policy[TCA_TBF_MAX + 1] = {
328 [TCA_TBF_PARMS] = { .len = sizeof(struct tc_tbf_qopt) },
329 [TCA_TBF_RTAB] = { .type = NLA_BINARY, .len = TC_RTAB_SIZE },
330 [TCA_TBF_PTAB] = { .type = NLA_BINARY, .len = TC_RTAB_SIZE },
331 [TCA_TBF_RATE64] = { .type = NLA_U64 },
332 [TCA_TBF_PRATE64] = { .type = NLA_U64 },
333 [TCA_TBF_BURST] = { .type = NLA_U32 },
334 [TCA_TBF_PBURST] = { .type = NLA_U32 },
335};
336
337static int tbf_change(struct Qdisc *sch, struct nlattr *opt,
338 struct netlink_ext_ack *extack)
339{
340 int err;
341 struct tbf_sched_data *q = qdisc_priv(sch);
342 struct nlattr *tb[TCA_TBF_MAX + 1];
343 struct tc_tbf_qopt *qopt;
344 struct Qdisc *child = NULL;
345 struct psched_ratecfg rate;
346 struct psched_ratecfg peak;
347 u64 max_size;
348 s64 buffer, mtu;
349 u64 rate64 = 0, prate64 = 0;
350
351 err = nla_parse_nested_deprecated(tb, TCA_TBF_MAX, opt, tbf_policy,
352 NULL);
353 if (err < 0)
354 return err;
355
356 err = -EINVAL;
357 if (tb[TCA_TBF_PARMS] == NULL)
358 goto done;
359
360 qopt = nla_data(tb[TCA_TBF_PARMS]);
361 if (qopt->rate.linklayer == TC_LINKLAYER_UNAWARE)
362 qdisc_put_rtab(qdisc_get_rtab(&qopt->rate,
363 tb[TCA_TBF_RTAB],
364 NULL));
365
366 if (qopt->peakrate.linklayer == TC_LINKLAYER_UNAWARE)
367 qdisc_put_rtab(qdisc_get_rtab(&qopt->peakrate,
368 tb[TCA_TBF_PTAB],
369 NULL));
370
371 buffer = min_t(u64, PSCHED_TICKS2NS(qopt->buffer), ~0U);
372 mtu = min_t(u64, PSCHED_TICKS2NS(qopt->mtu), ~0U);
373
374 if (tb[TCA_TBF_RATE64])
375 rate64 = nla_get_u64(tb[TCA_TBF_RATE64]);
376 psched_ratecfg_precompute(&rate, &qopt->rate, rate64);
377
378 if (tb[TCA_TBF_BURST]) {
379 max_size = nla_get_u32(tb[TCA_TBF_BURST]);
380 buffer = psched_l2t_ns(&rate, max_size);
381 } else {
382 max_size = min_t(u64, psched_ns_t2l(&rate, buffer), ~0U);
383 }
384
385 if (qopt->peakrate.rate) {
386 if (tb[TCA_TBF_PRATE64])
387 prate64 = nla_get_u64(tb[TCA_TBF_PRATE64]);
388 psched_ratecfg_precompute(&peak, &qopt->peakrate, prate64);
389 if (peak.rate_bytes_ps <= rate.rate_bytes_ps) {
390 pr_warn_ratelimited("sch_tbf: peakrate %llu is lower than or equals to rate %llu !\n",
391 peak.rate_bytes_ps, rate.rate_bytes_ps);
392 err = -EINVAL;
393 goto done;
394 }
395
396 if (tb[TCA_TBF_PBURST]) {
397 u32 pburst = nla_get_u32(tb[TCA_TBF_PBURST]);
398 max_size = min_t(u32, max_size, pburst);
399 mtu = psched_l2t_ns(&peak, pburst);
400 } else {
401 max_size = min_t(u64, max_size, psched_ns_t2l(&peak, mtu));
402 }
403 } else {
404 memset(&peak, 0, sizeof(peak));
405 }
406
407 if (max_size < psched_mtu(qdisc_dev(sch)))
408 pr_warn_ratelimited("sch_tbf: burst %llu is lower than device %s mtu (%u) !\n",
409 max_size, qdisc_dev(sch)->name,
410 psched_mtu(qdisc_dev(sch)));
411
412 if (!max_size) {
413 err = -EINVAL;
414 goto done;
415 }
416
417 if (q->qdisc != &noop_qdisc) {
418 err = fifo_set_limit(q->qdisc, qopt->limit);
419 if (err)
420 goto done;
421 } else if (qopt->limit > 0) {
422 child = fifo_create_dflt(sch, &bfifo_qdisc_ops, qopt->limit,
423 extack);
424 if (IS_ERR(child)) {
425 err = PTR_ERR(child);
426 goto done;
427 }
428
429 /* child is fifo, no need to check for noop_qdisc */
430 qdisc_hash_add(child, true);
431 }
432
433 sch_tree_lock(sch);
434 if (child) {
435 qdisc_tree_flush_backlog(q->qdisc);
436 qdisc_put(q->qdisc);
437 q->qdisc = child;
438 }
439 q->limit = qopt->limit;
440 if (tb[TCA_TBF_PBURST])
441 q->mtu = mtu;
442 else
443 q->mtu = PSCHED_TICKS2NS(qopt->mtu);
444 q->max_size = max_size;
445 if (tb[TCA_TBF_BURST])
446 q->buffer = buffer;
447 else
448 q->buffer = PSCHED_TICKS2NS(qopt->buffer);
449 q->tokens = q->buffer;
450 q->ptokens = q->mtu;
451
452 memcpy(&q->rate, &rate, sizeof(struct psched_ratecfg));
453 memcpy(&q->peak, &peak, sizeof(struct psched_ratecfg));
454
455 sch_tree_unlock(sch);
456 err = 0;
457
458 tbf_offload_change(sch);
459done:
460 return err;
461}
462
463static int tbf_init(struct Qdisc *sch, struct nlattr *opt,
464 struct netlink_ext_ack *extack)
465{
466 struct tbf_sched_data *q = qdisc_priv(sch);
467
468 qdisc_watchdog_init(&q->watchdog, sch);
469 q->qdisc = &noop_qdisc;
470
471 if (!opt)
472 return -EINVAL;
473
474 q->t_c = ktime_get_ns();
475
476 return tbf_change(sch, opt, extack);
477}
478
479static void tbf_destroy(struct Qdisc *sch)
480{
481 struct tbf_sched_data *q = qdisc_priv(sch);
482
483 qdisc_watchdog_cancel(&q->watchdog);
484 tbf_offload_destroy(sch);
485 qdisc_put(q->qdisc);
486}
487
488static int tbf_dump(struct Qdisc *sch, struct sk_buff *skb)
489{
490 struct tbf_sched_data *q = qdisc_priv(sch);
491 struct nlattr *nest;
492 struct tc_tbf_qopt opt;
493 int err;
494
495 err = tbf_offload_dump(sch);
496 if (err)
497 return err;
498
499 nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
500 if (nest == NULL)
501 goto nla_put_failure;
502
503 opt.limit = q->limit;
504 psched_ratecfg_getrate(&opt.rate, &q->rate);
505 if (tbf_peak_present(q))
506 psched_ratecfg_getrate(&opt.peakrate, &q->peak);
507 else
508 memset(&opt.peakrate, 0, sizeof(opt.peakrate));
509 opt.mtu = PSCHED_NS2TICKS(q->mtu);
510 opt.buffer = PSCHED_NS2TICKS(q->buffer);
511 if (nla_put(skb, TCA_TBF_PARMS, sizeof(opt), &opt))
512 goto nla_put_failure;
513 if (q->rate.rate_bytes_ps >= (1ULL << 32) &&
514 nla_put_u64_64bit(skb, TCA_TBF_RATE64, q->rate.rate_bytes_ps,
515 TCA_TBF_PAD))
516 goto nla_put_failure;
517 if (tbf_peak_present(q) &&
518 q->peak.rate_bytes_ps >= (1ULL << 32) &&
519 nla_put_u64_64bit(skb, TCA_TBF_PRATE64, q->peak.rate_bytes_ps,
520 TCA_TBF_PAD))
521 goto nla_put_failure;
522
523 return nla_nest_end(skb, nest);
524
525nla_put_failure:
526 nla_nest_cancel(skb, nest);
527 return -1;
528}
529
530static int tbf_dump_class(struct Qdisc *sch, unsigned long cl,
531 struct sk_buff *skb, struct tcmsg *tcm)
532{
533 struct tbf_sched_data *q = qdisc_priv(sch);
534
535 tcm->tcm_handle |= TC_H_MIN(1);
536 tcm->tcm_info = q->qdisc->handle;
537
538 return 0;
539}
540
541static int tbf_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
542 struct Qdisc **old, struct netlink_ext_ack *extack)
543{
544 struct tbf_sched_data *q = qdisc_priv(sch);
545
546 if (new == NULL)
547 new = &noop_qdisc;
548
549 *old = qdisc_replace(sch, new, &q->qdisc);
550 return 0;
551}
552
553static struct Qdisc *tbf_leaf(struct Qdisc *sch, unsigned long arg)
554{
555 struct tbf_sched_data *q = qdisc_priv(sch);
556 return q->qdisc;
557}
558
559static unsigned long tbf_find(struct Qdisc *sch, u32 classid)
560{
561 return 1;
562}
563
564static void tbf_walk(struct Qdisc *sch, struct qdisc_walker *walker)
565{
566 if (!walker->stop) {
567 if (walker->count >= walker->skip)
568 if (walker->fn(sch, 1, walker) < 0) {
569 walker->stop = 1;
570 return;
571 }
572 walker->count++;
573 }
574}
575
576static const struct Qdisc_class_ops tbf_class_ops = {
577 .graft = tbf_graft,
578 .leaf = tbf_leaf,
579 .find = tbf_find,
580 .walk = tbf_walk,
581 .dump = tbf_dump_class,
582};
583
584static struct Qdisc_ops tbf_qdisc_ops __read_mostly = {
585 .next = NULL,
586 .cl_ops = &tbf_class_ops,
587 .id = "tbf",
588 .priv_size = sizeof(struct tbf_sched_data),
589 .enqueue = tbf_enqueue,
590 .dequeue = tbf_dequeue,
591 .peek = qdisc_peek_dequeued,
592 .init = tbf_init,
593 .reset = tbf_reset,
594 .destroy = tbf_destroy,
595 .change = tbf_change,
596 .dump = tbf_dump,
597 .owner = THIS_MODULE,
598};
599
600static int __init tbf_module_init(void)
601{
602 return register_qdisc(&tbf_qdisc_ops);
603}
604
605static void __exit tbf_module_exit(void)
606{
607 unregister_qdisc(&tbf_qdisc_ops);
608}
609module_init(tbf_module_init)
610module_exit(tbf_module_exit)
611MODULE_LICENSE("GPL");