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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/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/* Parameters */
102 u32 limit; /* Maximal length of backlog: bytes */
103 u32 buffer; /* Token bucket depth/rate: MUST BE >= MTU/B */
104 u32 mtu;
105 u32 max_size;
106 struct qdisc_rate_table *R_tab;
107 struct qdisc_rate_table *P_tab;
108
109/* Variables */
110 long tokens; /* Current number of B tokens */
111 long ptokens; /* Current number of P tokens */
112 psched_time_t t_c; /* Time check-point */
113 struct Qdisc *qdisc; /* Inner qdisc, default - bfifo queue */
114 struct qdisc_watchdog watchdog; /* Watchdog timer */
115};
116
117#define L2T(q, L) qdisc_l2t((q)->R_tab, L)
118#define L2T_P(q, L) qdisc_l2t((q)->P_tab, L)
119
120static int tbf_enqueue(struct sk_buff *skb, struct Qdisc *sch)
121{
122 struct tbf_sched_data *q = qdisc_priv(sch);
123 int ret;
124
125 if (qdisc_pkt_len(skb) > q->max_size)
126 return qdisc_reshape_fail(skb, sch);
127
128 ret = qdisc_enqueue(skb, q->qdisc);
129 if (ret != NET_XMIT_SUCCESS) {
130 if (net_xmit_drop_count(ret))
131 sch->qstats.drops++;
132 return ret;
133 }
134
135 sch->q.qlen++;
136 return NET_XMIT_SUCCESS;
137}
138
139static unsigned int tbf_drop(struct Qdisc *sch)
140{
141 struct tbf_sched_data *q = qdisc_priv(sch);
142 unsigned int len = 0;
143
144 if (q->qdisc->ops->drop && (len = q->qdisc->ops->drop(q->qdisc)) != 0) {
145 sch->q.qlen--;
146 sch->qstats.drops++;
147 }
148 return len;
149}
150
151static struct sk_buff *tbf_dequeue(struct Qdisc *sch)
152{
153 struct tbf_sched_data *q = qdisc_priv(sch);
154 struct sk_buff *skb;
155
156 skb = q->qdisc->ops->peek(q->qdisc);
157
158 if (skb) {
159 psched_time_t now;
160 long toks;
161 long ptoks = 0;
162 unsigned int len = qdisc_pkt_len(skb);
163
164 now = psched_get_time();
165 toks = psched_tdiff_bounded(now, q->t_c, q->buffer);
166
167 if (q->P_tab) {
168 ptoks = toks + q->ptokens;
169 if (ptoks > (long)q->mtu)
170 ptoks = q->mtu;
171 ptoks -= L2T_P(q, len);
172 }
173 toks += q->tokens;
174 if (toks > (long)q->buffer)
175 toks = q->buffer;
176 toks -= L2T(q, len);
177
178 if ((toks|ptoks) >= 0) {
179 skb = qdisc_dequeue_peeked(q->qdisc);
180 if (unlikely(!skb))
181 return NULL;
182
183 q->t_c = now;
184 q->tokens = toks;
185 q->ptokens = ptoks;
186 sch->q.qlen--;
187 qdisc_unthrottled(sch);
188 qdisc_bstats_update(sch, skb);
189 return skb;
190 }
191
192 qdisc_watchdog_schedule(&q->watchdog,
193 now + max_t(long, -toks, -ptoks));
194
195 /* Maybe we have a shorter packet in the queue,
196 which can be sent now. It sounds cool,
197 but, however, this is wrong in principle.
198 We MUST NOT reorder packets under these circumstances.
199
200 Really, if we split the flow into independent
201 subflows, it would be a very good solution.
202 This is the main idea of all FQ algorithms
203 (cf. CSZ, HPFQ, HFSC)
204 */
205
206 sch->qstats.overlimits++;
207 }
208 return NULL;
209}
210
211static void tbf_reset(struct Qdisc *sch)
212{
213 struct tbf_sched_data *q = qdisc_priv(sch);
214
215 qdisc_reset(q->qdisc);
216 sch->q.qlen = 0;
217 q->t_c = psched_get_time();
218 q->tokens = q->buffer;
219 q->ptokens = q->mtu;
220 qdisc_watchdog_cancel(&q->watchdog);
221}
222
223static const struct nla_policy tbf_policy[TCA_TBF_MAX + 1] = {
224 [TCA_TBF_PARMS] = { .len = sizeof(struct tc_tbf_qopt) },
225 [TCA_TBF_RTAB] = { .type = NLA_BINARY, .len = TC_RTAB_SIZE },
226 [TCA_TBF_PTAB] = { .type = NLA_BINARY, .len = TC_RTAB_SIZE },
227};
228
229static int tbf_change(struct Qdisc *sch, struct nlattr *opt)
230{
231 int err;
232 struct tbf_sched_data *q = qdisc_priv(sch);
233 struct nlattr *tb[TCA_TBF_PTAB + 1];
234 struct tc_tbf_qopt *qopt;
235 struct qdisc_rate_table *rtab = NULL;
236 struct qdisc_rate_table *ptab = NULL;
237 struct Qdisc *child = NULL;
238 int max_size, n;
239
240 err = nla_parse_nested(tb, TCA_TBF_PTAB, opt, tbf_policy);
241 if (err < 0)
242 return err;
243
244 err = -EINVAL;
245 if (tb[TCA_TBF_PARMS] == NULL)
246 goto done;
247
248 qopt = nla_data(tb[TCA_TBF_PARMS]);
249 rtab = qdisc_get_rtab(&qopt->rate, tb[TCA_TBF_RTAB]);
250 if (rtab == NULL)
251 goto done;
252
253 if (qopt->peakrate.rate) {
254 if (qopt->peakrate.rate > qopt->rate.rate)
255 ptab = qdisc_get_rtab(&qopt->peakrate, tb[TCA_TBF_PTAB]);
256 if (ptab == NULL)
257 goto done;
258 }
259
260 for (n = 0; n < 256; n++)
261 if (rtab->data[n] > qopt->buffer)
262 break;
263 max_size = (n << qopt->rate.cell_log) - 1;
264 if (ptab) {
265 int size;
266
267 for (n = 0; n < 256; n++)
268 if (ptab->data[n] > qopt->mtu)
269 break;
270 size = (n << qopt->peakrate.cell_log) - 1;
271 if (size < max_size)
272 max_size = size;
273 }
274 if (max_size < 0)
275 goto done;
276
277 if (q->qdisc != &noop_qdisc) {
278 err = fifo_set_limit(q->qdisc, qopt->limit);
279 if (err)
280 goto done;
281 } else if (qopt->limit > 0) {
282 child = fifo_create_dflt(sch, &bfifo_qdisc_ops, qopt->limit);
283 if (IS_ERR(child)) {
284 err = PTR_ERR(child);
285 goto done;
286 }
287 }
288
289 sch_tree_lock(sch);
290 if (child) {
291 qdisc_tree_decrease_qlen(q->qdisc, q->qdisc->q.qlen);
292 qdisc_destroy(q->qdisc);
293 q->qdisc = child;
294 }
295 q->limit = qopt->limit;
296 q->mtu = qopt->mtu;
297 q->max_size = max_size;
298 q->buffer = qopt->buffer;
299 q->tokens = q->buffer;
300 q->ptokens = q->mtu;
301
302 swap(q->R_tab, rtab);
303 swap(q->P_tab, ptab);
304
305 sch_tree_unlock(sch);
306 err = 0;
307done:
308 if (rtab)
309 qdisc_put_rtab(rtab);
310 if (ptab)
311 qdisc_put_rtab(ptab);
312 return err;
313}
314
315static int tbf_init(struct Qdisc *sch, struct nlattr *opt)
316{
317 struct tbf_sched_data *q = qdisc_priv(sch);
318
319 if (opt == NULL)
320 return -EINVAL;
321
322 q->t_c = psched_get_time();
323 qdisc_watchdog_init(&q->watchdog, sch);
324 q->qdisc = &noop_qdisc;
325
326 return tbf_change(sch, opt);
327}
328
329static void tbf_destroy(struct Qdisc *sch)
330{
331 struct tbf_sched_data *q = qdisc_priv(sch);
332
333 qdisc_watchdog_cancel(&q->watchdog);
334
335 if (q->P_tab)
336 qdisc_put_rtab(q->P_tab);
337 if (q->R_tab)
338 qdisc_put_rtab(q->R_tab);
339
340 qdisc_destroy(q->qdisc);
341}
342
343static int tbf_dump(struct Qdisc *sch, struct sk_buff *skb)
344{
345 struct tbf_sched_data *q = qdisc_priv(sch);
346 struct nlattr *nest;
347 struct tc_tbf_qopt opt;
348
349 sch->qstats.backlog = q->qdisc->qstats.backlog;
350 nest = nla_nest_start(skb, TCA_OPTIONS);
351 if (nest == NULL)
352 goto nla_put_failure;
353
354 opt.limit = q->limit;
355 opt.rate = q->R_tab->rate;
356 if (q->P_tab)
357 opt.peakrate = q->P_tab->rate;
358 else
359 memset(&opt.peakrate, 0, sizeof(opt.peakrate));
360 opt.mtu = q->mtu;
361 opt.buffer = q->buffer;
362 if (nla_put(skb, TCA_TBF_PARMS, sizeof(opt), &opt))
363 goto nla_put_failure;
364
365 nla_nest_end(skb, nest);
366 return skb->len;
367
368nla_put_failure:
369 nla_nest_cancel(skb, nest);
370 return -1;
371}
372
373static int tbf_dump_class(struct Qdisc *sch, unsigned long cl,
374 struct sk_buff *skb, struct tcmsg *tcm)
375{
376 struct tbf_sched_data *q = qdisc_priv(sch);
377
378 tcm->tcm_handle |= TC_H_MIN(1);
379 tcm->tcm_info = q->qdisc->handle;
380
381 return 0;
382}
383
384static int tbf_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
385 struct Qdisc **old)
386{
387 struct tbf_sched_data *q = qdisc_priv(sch);
388
389 if (new == NULL)
390 new = &noop_qdisc;
391
392 sch_tree_lock(sch);
393 *old = q->qdisc;
394 q->qdisc = new;
395 qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
396 qdisc_reset(*old);
397 sch_tree_unlock(sch);
398
399 return 0;
400}
401
402static struct Qdisc *tbf_leaf(struct Qdisc *sch, unsigned long arg)
403{
404 struct tbf_sched_data *q = qdisc_priv(sch);
405 return q->qdisc;
406}
407
408static unsigned long tbf_get(struct Qdisc *sch, u32 classid)
409{
410 return 1;
411}
412
413static void tbf_put(struct Qdisc *sch, unsigned long arg)
414{
415}
416
417static void tbf_walk(struct Qdisc *sch, struct qdisc_walker *walker)
418{
419 if (!walker->stop) {
420 if (walker->count >= walker->skip)
421 if (walker->fn(sch, 1, walker) < 0) {
422 walker->stop = 1;
423 return;
424 }
425 walker->count++;
426 }
427}
428
429static const struct Qdisc_class_ops tbf_class_ops = {
430 .graft = tbf_graft,
431 .leaf = tbf_leaf,
432 .get = tbf_get,
433 .put = tbf_put,
434 .walk = tbf_walk,
435 .dump = tbf_dump_class,
436};
437
438static struct Qdisc_ops tbf_qdisc_ops __read_mostly = {
439 .next = NULL,
440 .cl_ops = &tbf_class_ops,
441 .id = "tbf",
442 .priv_size = sizeof(struct tbf_sched_data),
443 .enqueue = tbf_enqueue,
444 .dequeue = tbf_dequeue,
445 .peek = qdisc_peek_dequeued,
446 .drop = tbf_drop,
447 .init = tbf_init,
448 .reset = tbf_reset,
449 .destroy = tbf_destroy,
450 .change = tbf_change,
451 .dump = tbf_dump,
452 .owner = THIS_MODULE,
453};
454
455static int __init tbf_module_init(void)
456{
457 return register_qdisc(&tbf_qdisc_ops);
458}
459
460static void __exit tbf_module_exit(void)
461{
462 unregister_qdisc(&tbf_qdisc_ops);
463}
464module_init(tbf_module_init)
465module_exit(tbf_module_exit)
466MODULE_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/gso.h>
17#include <net/netlink.h>
18#include <net/sch_generic.h>
19#include <net/pkt_cls.h>
20#include <net/pkt_sched.h>
21
22
23/* Simple Token Bucket Filter.
24 =======================================
25
26 SOURCE.
27 -------
28
29 None.
30
31 Description.
32 ------------
33
34 A data flow obeys TBF with rate R and depth B, if for any
35 time interval t_i...t_f the number of transmitted bits
36 does not exceed B + R*(t_f-t_i).
37
38 Packetized version of this definition:
39 The sequence of packets of sizes s_i served at moments t_i
40 obeys TBF, if for any i<=k:
41
42 s_i+....+s_k <= B + R*(t_k - t_i)
43
44 Algorithm.
45 ----------
46
47 Let N(t_i) be B/R initially and N(t) grow continuously with time as:
48
49 N(t+delta) = min{B/R, N(t) + delta}
50
51 If the first packet in queue has length S, it may be
52 transmitted only at the time t_* when S/R <= N(t_*),
53 and in this case N(t) jumps:
54
55 N(t_* + 0) = N(t_* - 0) - S/R.
56
57
58
59 Actually, QoS requires two TBF to be applied to a data stream.
60 One of them controls steady state burst size, another
61 one with rate P (peak rate) and depth M (equal to link MTU)
62 limits bursts at a smaller time scale.
63
64 It is easy to see that P>R, and B>M. If P is infinity, this double
65 TBF is equivalent to a single one.
66
67 When TBF works in reshaping mode, latency is estimated as:
68
69 lat = max ((L-B)/R, (L-M)/P)
70
71
72 NOTES.
73 ------
74
75 If TBF throttles, it starts a watchdog timer, which will wake it up
76 when it is ready to transmit.
77 Note that the minimal timer resolution is 1/HZ.
78 If no new packets arrive during this period,
79 or if the device is not awaken by EOI for some previous packet,
80 TBF can stop its activity for 1/HZ.
81
82
83 This means, that with depth B, the maximal rate is
84
85 R_crit = B*HZ
86
87 F.e. for 10Mbit ethernet and HZ=100 the minimal allowed B is ~10Kbytes.
88
89 Note that the peak rate TBF is much more tough: with MTU 1500
90 P_crit = 150Kbytes/sec. So, if you need greater peak
91 rates, use alpha with HZ=1000 :-)
92
93 With classful TBF, limit is just kept for backwards compatibility.
94 It is passed to the default bfifo qdisc - if the inner qdisc is
95 changed the limit is not effective anymore.
96*/
97
98struct tbf_sched_data {
99/* Parameters */
100 u32 limit; /* Maximal length of backlog: bytes */
101 u32 max_size;
102 s64 buffer; /* Token bucket depth/rate: MUST BE >= MTU/B */
103 s64 mtu;
104 struct psched_ratecfg rate;
105 struct psched_ratecfg peak;
106
107/* Variables */
108 s64 tokens; /* Current number of B tokens */
109 s64 ptokens; /* Current number of P tokens */
110 s64 t_c; /* Time check-point */
111 struct Qdisc *qdisc; /* Inner qdisc, default - bfifo queue */
112 struct qdisc_watchdog watchdog; /* Watchdog timer */
113};
114
115
116/* Time to Length, convert time in ns to length in bytes
117 * to determinate how many bytes can be sent in given time.
118 */
119static u64 psched_ns_t2l(const struct psched_ratecfg *r,
120 u64 time_in_ns)
121{
122 /* The formula is :
123 * len = (time_in_ns * r->rate_bytes_ps) / NSEC_PER_SEC
124 */
125 u64 len = time_in_ns * r->rate_bytes_ps;
126
127 do_div(len, NSEC_PER_SEC);
128
129 if (unlikely(r->linklayer == TC_LINKLAYER_ATM)) {
130 do_div(len, 53);
131 len = len * 48;
132 }
133
134 if (len > r->overhead)
135 len -= r->overhead;
136 else
137 len = 0;
138
139 return len;
140}
141
142static void tbf_offload_change(struct Qdisc *sch)
143{
144 struct tbf_sched_data *q = qdisc_priv(sch);
145 struct net_device *dev = qdisc_dev(sch);
146 struct tc_tbf_qopt_offload qopt;
147
148 if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
149 return;
150
151 qopt.command = TC_TBF_REPLACE;
152 qopt.handle = sch->handle;
153 qopt.parent = sch->parent;
154 qopt.replace_params.rate = q->rate;
155 qopt.replace_params.max_size = q->max_size;
156 qopt.replace_params.qstats = &sch->qstats;
157
158 dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_TBF, &qopt);
159}
160
161static void tbf_offload_destroy(struct Qdisc *sch)
162{
163 struct net_device *dev = qdisc_dev(sch);
164 struct tc_tbf_qopt_offload qopt;
165
166 if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
167 return;
168
169 qopt.command = TC_TBF_DESTROY;
170 qopt.handle = sch->handle;
171 qopt.parent = sch->parent;
172 dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_TBF, &qopt);
173}
174
175static int tbf_offload_dump(struct Qdisc *sch)
176{
177 struct tc_tbf_qopt_offload qopt;
178
179 qopt.command = TC_TBF_STATS;
180 qopt.handle = sch->handle;
181 qopt.parent = sch->parent;
182 qopt.stats.bstats = &sch->bstats;
183 qopt.stats.qstats = &sch->qstats;
184
185 return qdisc_offload_dump_helper(sch, TC_SETUP_QDISC_TBF, &qopt);
186}
187
188static void tbf_offload_graft(struct Qdisc *sch, struct Qdisc *new,
189 struct Qdisc *old, struct netlink_ext_ack *extack)
190{
191 struct tc_tbf_qopt_offload graft_offload = {
192 .handle = sch->handle,
193 .parent = sch->parent,
194 .child_handle = new->handle,
195 .command = TC_TBF_GRAFT,
196 };
197
198 qdisc_offload_graft_helper(qdisc_dev(sch), sch, new, old,
199 TC_SETUP_QDISC_TBF, &graft_offload, extack);
200}
201
202/* GSO packet is too big, segment it so that tbf can transmit
203 * each segment in time
204 */
205static int tbf_segment(struct sk_buff *skb, struct Qdisc *sch,
206 struct sk_buff **to_free)
207{
208 struct tbf_sched_data *q = qdisc_priv(sch);
209 struct sk_buff *segs, *nskb;
210 netdev_features_t features = netif_skb_features(skb);
211 unsigned int len = 0, prev_len = qdisc_pkt_len(skb);
212 int ret, nb;
213
214 segs = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK);
215
216 if (IS_ERR_OR_NULL(segs))
217 return qdisc_drop(skb, sch, to_free);
218
219 nb = 0;
220 skb_list_walk_safe(segs, segs, nskb) {
221 skb_mark_not_on_list(segs);
222 qdisc_skb_cb(segs)->pkt_len = segs->len;
223 len += segs->len;
224 ret = qdisc_enqueue(segs, q->qdisc, to_free);
225 if (ret != NET_XMIT_SUCCESS) {
226 if (net_xmit_drop_count(ret))
227 qdisc_qstats_drop(sch);
228 } else {
229 nb++;
230 }
231 }
232 sch->q.qlen += nb;
233 if (nb > 1)
234 qdisc_tree_reduce_backlog(sch, 1 - nb, prev_len - len);
235 consume_skb(skb);
236 return nb > 0 ? NET_XMIT_SUCCESS : NET_XMIT_DROP;
237}
238
239static int tbf_enqueue(struct sk_buff *skb, struct Qdisc *sch,
240 struct sk_buff **to_free)
241{
242 struct tbf_sched_data *q = qdisc_priv(sch);
243 unsigned int len = qdisc_pkt_len(skb);
244 int ret;
245
246 if (qdisc_pkt_len(skb) > q->max_size) {
247 if (skb_is_gso(skb) &&
248 skb_gso_validate_mac_len(skb, q->max_size))
249 return tbf_segment(skb, sch, to_free);
250 return qdisc_drop(skb, sch, to_free);
251 }
252 ret = qdisc_enqueue(skb, q->qdisc, to_free);
253 if (ret != NET_XMIT_SUCCESS) {
254 if (net_xmit_drop_count(ret))
255 qdisc_qstats_drop(sch);
256 return ret;
257 }
258
259 sch->qstats.backlog += len;
260 sch->q.qlen++;
261 return NET_XMIT_SUCCESS;
262}
263
264static bool tbf_peak_present(const struct tbf_sched_data *q)
265{
266 return q->peak.rate_bytes_ps;
267}
268
269static struct sk_buff *tbf_dequeue(struct Qdisc *sch)
270{
271 struct tbf_sched_data *q = qdisc_priv(sch);
272 struct sk_buff *skb;
273
274 skb = q->qdisc->ops->peek(q->qdisc);
275
276 if (skb) {
277 s64 now;
278 s64 toks;
279 s64 ptoks = 0;
280 unsigned int len = qdisc_pkt_len(skb);
281
282 now = ktime_get_ns();
283 toks = min_t(s64, now - q->t_c, q->buffer);
284
285 if (tbf_peak_present(q)) {
286 ptoks = toks + q->ptokens;
287 if (ptoks > q->mtu)
288 ptoks = q->mtu;
289 ptoks -= (s64) psched_l2t_ns(&q->peak, len);
290 }
291 toks += q->tokens;
292 if (toks > q->buffer)
293 toks = q->buffer;
294 toks -= (s64) psched_l2t_ns(&q->rate, len);
295
296 if ((toks|ptoks) >= 0) {
297 skb = qdisc_dequeue_peeked(q->qdisc);
298 if (unlikely(!skb))
299 return NULL;
300
301 q->t_c = now;
302 q->tokens = toks;
303 q->ptokens = ptoks;
304 qdisc_qstats_backlog_dec(sch, skb);
305 sch->q.qlen--;
306 qdisc_bstats_update(sch, skb);
307 return skb;
308 }
309
310 qdisc_watchdog_schedule_ns(&q->watchdog,
311 now + max_t(long, -toks, -ptoks));
312
313 /* Maybe we have a shorter packet in the queue,
314 which can be sent now. It sounds cool,
315 but, however, this is wrong in principle.
316 We MUST NOT reorder packets under these circumstances.
317
318 Really, if we split the flow into independent
319 subflows, it would be a very good solution.
320 This is the main idea of all FQ algorithms
321 (cf. CSZ, HPFQ, HFSC)
322 */
323
324 qdisc_qstats_overlimit(sch);
325 }
326 return NULL;
327}
328
329static void tbf_reset(struct Qdisc *sch)
330{
331 struct tbf_sched_data *q = qdisc_priv(sch);
332
333 qdisc_reset(q->qdisc);
334 q->t_c = ktime_get_ns();
335 q->tokens = q->buffer;
336 q->ptokens = q->mtu;
337 qdisc_watchdog_cancel(&q->watchdog);
338}
339
340static const struct nla_policy tbf_policy[TCA_TBF_MAX + 1] = {
341 [TCA_TBF_PARMS] = { .len = sizeof(struct tc_tbf_qopt) },
342 [TCA_TBF_RTAB] = { .type = NLA_BINARY, .len = TC_RTAB_SIZE },
343 [TCA_TBF_PTAB] = { .type = NLA_BINARY, .len = TC_RTAB_SIZE },
344 [TCA_TBF_RATE64] = { .type = NLA_U64 },
345 [TCA_TBF_PRATE64] = { .type = NLA_U64 },
346 [TCA_TBF_BURST] = { .type = NLA_U32 },
347 [TCA_TBF_PBURST] = { .type = NLA_U32 },
348};
349
350static int tbf_change(struct Qdisc *sch, struct nlattr *opt,
351 struct netlink_ext_ack *extack)
352{
353 int err;
354 struct tbf_sched_data *q = qdisc_priv(sch);
355 struct nlattr *tb[TCA_TBF_MAX + 1];
356 struct tc_tbf_qopt *qopt;
357 struct Qdisc *child = NULL;
358 struct Qdisc *old = NULL;
359 struct psched_ratecfg rate;
360 struct psched_ratecfg peak;
361 u64 max_size;
362 s64 buffer, mtu;
363 u64 rate64 = 0, prate64 = 0;
364
365 err = nla_parse_nested_deprecated(tb, TCA_TBF_MAX, opt, tbf_policy,
366 NULL);
367 if (err < 0)
368 return err;
369
370 err = -EINVAL;
371 if (tb[TCA_TBF_PARMS] == NULL)
372 goto done;
373
374 qopt = nla_data(tb[TCA_TBF_PARMS]);
375 if (qopt->rate.linklayer == TC_LINKLAYER_UNAWARE)
376 qdisc_put_rtab(qdisc_get_rtab(&qopt->rate,
377 tb[TCA_TBF_RTAB],
378 NULL));
379
380 if (qopt->peakrate.linklayer == TC_LINKLAYER_UNAWARE)
381 qdisc_put_rtab(qdisc_get_rtab(&qopt->peakrate,
382 tb[TCA_TBF_PTAB],
383 NULL));
384
385 buffer = min_t(u64, PSCHED_TICKS2NS(qopt->buffer), ~0U);
386 mtu = min_t(u64, PSCHED_TICKS2NS(qopt->mtu), ~0U);
387
388 if (tb[TCA_TBF_RATE64])
389 rate64 = nla_get_u64(tb[TCA_TBF_RATE64]);
390 psched_ratecfg_precompute(&rate, &qopt->rate, rate64);
391
392 if (tb[TCA_TBF_BURST]) {
393 max_size = nla_get_u32(tb[TCA_TBF_BURST]);
394 buffer = psched_l2t_ns(&rate, max_size);
395 } else {
396 max_size = min_t(u64, psched_ns_t2l(&rate, buffer), ~0U);
397 }
398
399 if (qopt->peakrate.rate) {
400 if (tb[TCA_TBF_PRATE64])
401 prate64 = nla_get_u64(tb[TCA_TBF_PRATE64]);
402 psched_ratecfg_precompute(&peak, &qopt->peakrate, prate64);
403 if (peak.rate_bytes_ps <= rate.rate_bytes_ps) {
404 pr_warn_ratelimited("sch_tbf: peakrate %llu is lower than or equals to rate %llu !\n",
405 peak.rate_bytes_ps, rate.rate_bytes_ps);
406 err = -EINVAL;
407 goto done;
408 }
409
410 if (tb[TCA_TBF_PBURST]) {
411 u32 pburst = nla_get_u32(tb[TCA_TBF_PBURST]);
412 max_size = min_t(u32, max_size, pburst);
413 mtu = psched_l2t_ns(&peak, pburst);
414 } else {
415 max_size = min_t(u64, max_size, psched_ns_t2l(&peak, mtu));
416 }
417 } else {
418 memset(&peak, 0, sizeof(peak));
419 }
420
421 if (max_size < psched_mtu(qdisc_dev(sch)))
422 pr_warn_ratelimited("sch_tbf: burst %llu is lower than device %s mtu (%u) !\n",
423 max_size, qdisc_dev(sch)->name,
424 psched_mtu(qdisc_dev(sch)));
425
426 if (!max_size) {
427 err = -EINVAL;
428 goto done;
429 }
430
431 if (q->qdisc != &noop_qdisc) {
432 err = fifo_set_limit(q->qdisc, qopt->limit);
433 if (err)
434 goto done;
435 } else if (qopt->limit > 0) {
436 child = fifo_create_dflt(sch, &bfifo_qdisc_ops, qopt->limit,
437 extack);
438 if (IS_ERR(child)) {
439 err = PTR_ERR(child);
440 goto done;
441 }
442
443 /* child is fifo, no need to check for noop_qdisc */
444 qdisc_hash_add(child, true);
445 }
446
447 sch_tree_lock(sch);
448 if (child) {
449 qdisc_tree_flush_backlog(q->qdisc);
450 old = q->qdisc;
451 q->qdisc = child;
452 }
453 q->limit = qopt->limit;
454 if (tb[TCA_TBF_PBURST])
455 q->mtu = mtu;
456 else
457 q->mtu = PSCHED_TICKS2NS(qopt->mtu);
458 q->max_size = max_size;
459 if (tb[TCA_TBF_BURST])
460 q->buffer = buffer;
461 else
462 q->buffer = PSCHED_TICKS2NS(qopt->buffer);
463 q->tokens = q->buffer;
464 q->ptokens = q->mtu;
465
466 memcpy(&q->rate, &rate, sizeof(struct psched_ratecfg));
467 memcpy(&q->peak, &peak, sizeof(struct psched_ratecfg));
468
469 sch_tree_unlock(sch);
470 qdisc_put(old);
471 err = 0;
472
473 tbf_offload_change(sch);
474done:
475 return err;
476}
477
478static int tbf_init(struct Qdisc *sch, struct nlattr *opt,
479 struct netlink_ext_ack *extack)
480{
481 struct tbf_sched_data *q = qdisc_priv(sch);
482
483 qdisc_watchdog_init(&q->watchdog, sch);
484 q->qdisc = &noop_qdisc;
485
486 if (!opt)
487 return -EINVAL;
488
489 q->t_c = ktime_get_ns();
490
491 return tbf_change(sch, opt, extack);
492}
493
494static void tbf_destroy(struct Qdisc *sch)
495{
496 struct tbf_sched_data *q = qdisc_priv(sch);
497
498 qdisc_watchdog_cancel(&q->watchdog);
499 tbf_offload_destroy(sch);
500 qdisc_put(q->qdisc);
501}
502
503static int tbf_dump(struct Qdisc *sch, struct sk_buff *skb)
504{
505 struct tbf_sched_data *q = qdisc_priv(sch);
506 struct nlattr *nest;
507 struct tc_tbf_qopt opt;
508 int err;
509
510 err = tbf_offload_dump(sch);
511 if (err)
512 return err;
513
514 nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
515 if (nest == NULL)
516 goto nla_put_failure;
517
518 opt.limit = q->limit;
519 psched_ratecfg_getrate(&opt.rate, &q->rate);
520 if (tbf_peak_present(q))
521 psched_ratecfg_getrate(&opt.peakrate, &q->peak);
522 else
523 memset(&opt.peakrate, 0, sizeof(opt.peakrate));
524 opt.mtu = PSCHED_NS2TICKS(q->mtu);
525 opt.buffer = PSCHED_NS2TICKS(q->buffer);
526 if (nla_put(skb, TCA_TBF_PARMS, sizeof(opt), &opt))
527 goto nla_put_failure;
528 if (q->rate.rate_bytes_ps >= (1ULL << 32) &&
529 nla_put_u64_64bit(skb, TCA_TBF_RATE64, q->rate.rate_bytes_ps,
530 TCA_TBF_PAD))
531 goto nla_put_failure;
532 if (tbf_peak_present(q) &&
533 q->peak.rate_bytes_ps >= (1ULL << 32) &&
534 nla_put_u64_64bit(skb, TCA_TBF_PRATE64, q->peak.rate_bytes_ps,
535 TCA_TBF_PAD))
536 goto nla_put_failure;
537
538 return nla_nest_end(skb, nest);
539
540nla_put_failure:
541 nla_nest_cancel(skb, nest);
542 return -1;
543}
544
545static int tbf_dump_class(struct Qdisc *sch, unsigned long cl,
546 struct sk_buff *skb, struct tcmsg *tcm)
547{
548 struct tbf_sched_data *q = qdisc_priv(sch);
549
550 tcm->tcm_handle |= TC_H_MIN(1);
551 tcm->tcm_info = q->qdisc->handle;
552
553 return 0;
554}
555
556static int tbf_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
557 struct Qdisc **old, struct netlink_ext_ack *extack)
558{
559 struct tbf_sched_data *q = qdisc_priv(sch);
560
561 if (new == NULL)
562 new = &noop_qdisc;
563
564 *old = qdisc_replace(sch, new, &q->qdisc);
565
566 tbf_offload_graft(sch, new, *old, extack);
567 return 0;
568}
569
570static struct Qdisc *tbf_leaf(struct Qdisc *sch, unsigned long arg)
571{
572 struct tbf_sched_data *q = qdisc_priv(sch);
573 return q->qdisc;
574}
575
576static unsigned long tbf_find(struct Qdisc *sch, u32 classid)
577{
578 return 1;
579}
580
581static void tbf_walk(struct Qdisc *sch, struct qdisc_walker *walker)
582{
583 if (!walker->stop) {
584 tc_qdisc_stats_dump(sch, 1, walker);
585 }
586}
587
588static const struct Qdisc_class_ops tbf_class_ops = {
589 .graft = tbf_graft,
590 .leaf = tbf_leaf,
591 .find = tbf_find,
592 .walk = tbf_walk,
593 .dump = tbf_dump_class,
594};
595
596static struct Qdisc_ops tbf_qdisc_ops __read_mostly = {
597 .next = NULL,
598 .cl_ops = &tbf_class_ops,
599 .id = "tbf",
600 .priv_size = sizeof(struct tbf_sched_data),
601 .enqueue = tbf_enqueue,
602 .dequeue = tbf_dequeue,
603 .peek = qdisc_peek_dequeued,
604 .init = tbf_init,
605 .reset = tbf_reset,
606 .destroy = tbf_destroy,
607 .change = tbf_change,
608 .dump = tbf_dump,
609 .owner = THIS_MODULE,
610};
611MODULE_ALIAS_NET_SCH("tbf");
612
613static int __init tbf_module_init(void)
614{
615 return register_qdisc(&tbf_qdisc_ops);
616}
617
618static void __exit tbf_module_exit(void)
619{
620 unregister_qdisc(&tbf_qdisc_ops);
621}
622module_init(tbf_module_init)
623module_exit(tbf_module_exit)
624MODULE_LICENSE("GPL");
625MODULE_DESCRIPTION("Token Bucket Filter qdisc");