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Linux 5.7.7
[linux/fpc-iii.git] / net / sched / sch_red.c
blobc7de47c942e3b9f8d980377b53120b3088a93ab6
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * net/sched/sch_red.c Random Early Detection queue.
4 *
5 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
6 *
7 * Changes:
8 * J Hadi Salim 980914: computation fixes
9 * Alexey Makarenko <makar@phoenix.kharkov.ua> 990814: qave on idle link was calculated incorrectly.
10 * J Hadi Salim 980816: ECN support
11 */
12
13 #include <linux/module.h>
14 #include <linux/types.h>
15 #include <linux/kernel.h>
16 #include <linux/skbuff.h>
17 #include <net/pkt_sched.h>
18 #include <net/pkt_cls.h>
19 #include <net/inet_ecn.h>
20 #include <net/red.h>
21
22
23 /* Parameters, settable by user:
24 -----------------------------
25
26 limit - bytes (must be > qth_max + burst)
27
28 Hard limit on queue length, should be chosen >qth_max
29 to allow packet bursts. This parameter does not
30 affect the algorithms behaviour and can be chosen
31 arbitrarily high (well, less than ram size)
32 Really, this limit will never be reached
33 if RED works correctly.
34 */
35
36 struct red_sched_data {
37 u32 limit; /* HARD maximal queue length */
38
39 unsigned char flags;
40 /* Non-flags in tc_red_qopt.flags. */
41 unsigned char userbits;
42
43 struct timer_list adapt_timer;
44 struct Qdisc *sch;
45 struct red_parms parms;
46 struct red_vars vars;
47 struct red_stats stats;
48 struct Qdisc *qdisc;
49 };
50
51 static const u32 red_supported_flags = TC_RED_HISTORIC_FLAGS | TC_RED_NODROP;
52
53 static inline int red_use_ecn(struct red_sched_data *q)
54 {
55 return q->flags & TC_RED_ECN;
56 }
57
58 static inline int red_use_harddrop(struct red_sched_data *q)
59 {
60 return q->flags & TC_RED_HARDDROP;
61 }
62
63 static int red_use_nodrop(struct red_sched_data *q)
64 {
65 return q->flags & TC_RED_NODROP;
66 }
67
68 static int red_enqueue(struct sk_buff *skb, struct Qdisc *sch,
69 struct sk_buff **to_free)
70 {
71 struct red_sched_data *q = qdisc_priv(sch);
72 struct Qdisc *child = q->qdisc;
73 int ret;
74
75 q->vars.qavg = red_calc_qavg(&q->parms,
76 &q->vars,
77 child->qstats.backlog);
78
79 if (red_is_idling(&q->vars))
80 red_end_of_idle_period(&q->vars);
81
82 switch (red_action(&q->parms, &q->vars, q->vars.qavg)) {
83 case RED_DONT_MARK:
84 break;
85
86 case RED_PROB_MARK:
87 qdisc_qstats_overlimit(sch);
88 if (!red_use_ecn(q)) {
89 q->stats.prob_drop++;
90 goto congestion_drop;
91 }
92
93 if (INET_ECN_set_ce(skb)) {
94 q->stats.prob_mark++;
95 } else if (!red_use_nodrop(q)) {
96 q->stats.prob_drop++;
97 goto congestion_drop;
98 }
99
100 /* Non-ECT packet in ECN nodrop mode: queue it. */
101 break;
102
103 case RED_HARD_MARK:
104 qdisc_qstats_overlimit(sch);
105 if (red_use_harddrop(q) || !red_use_ecn(q)) {
106 q->stats.forced_drop++;
107 goto congestion_drop;
108 }
109
110 if (INET_ECN_set_ce(skb)) {
111 q->stats.forced_mark++;
112 } else if (!red_use_nodrop(q)) {
113 q->stats.forced_drop++;
114 goto congestion_drop;
115 }
116
117 /* Non-ECT packet in ECN nodrop mode: queue it. */
118 break;
119 }
120
121 ret = qdisc_enqueue(skb, child, to_free);
122 if (likely(ret == NET_XMIT_SUCCESS)) {
123 qdisc_qstats_backlog_inc(sch, skb);
124 sch->q.qlen++;
125 } else if (net_xmit_drop_count(ret)) {
126 q->stats.pdrop++;
127 qdisc_qstats_drop(sch);
128 }
129 return ret;
130
131 congestion_drop:
132 qdisc_drop(skb, sch, to_free);
133 return NET_XMIT_CN;
134 }
135
136 static struct sk_buff *red_dequeue(struct Qdisc *sch)
137 {
138 struct sk_buff *skb;
139 struct red_sched_data *q = qdisc_priv(sch);
140 struct Qdisc *child = q->qdisc;
141
142 skb = child->dequeue(child);
143 if (skb) {
144 qdisc_bstats_update(sch, skb);
145 qdisc_qstats_backlog_dec(sch, skb);
146 sch->q.qlen--;
147 } else {
148 if (!red_is_idling(&q->vars))
149 red_start_of_idle_period(&q->vars);
150 }
151 return skb;
152 }
153
154 static struct sk_buff *red_peek(struct Qdisc *sch)
155 {
156 struct red_sched_data *q = qdisc_priv(sch);
157 struct Qdisc *child = q->qdisc;
158
159 return child->ops->peek(child);
160 }
161
162 static void red_reset(struct Qdisc *sch)
163 {
164 struct red_sched_data *q = qdisc_priv(sch);
165
166 qdisc_reset(q->qdisc);
167 sch->qstats.backlog = 0;
168 sch->q.qlen = 0;
169 red_restart(&q->vars);
170 }
171
172 static int red_offload(struct Qdisc *sch, bool enable)
173 {
174 struct red_sched_data *q = qdisc_priv(sch);
175 struct net_device *dev = qdisc_dev(sch);
176 struct tc_red_qopt_offload opt = {
177 .handle = sch->handle,
178 .parent = sch->parent,
179 };
180
181 if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
182 return -EOPNOTSUPP;
183
184 if (enable) {
185 opt.command = TC_RED_REPLACE;
186 opt.set.min = q->parms.qth_min >> q->parms.Wlog;
187 opt.set.max = q->parms.qth_max >> q->parms.Wlog;
188 opt.set.probability = q->parms.max_P;
189 opt.set.limit = q->limit;
190 opt.set.is_ecn = red_use_ecn(q);
191 opt.set.is_harddrop = red_use_harddrop(q);
192 opt.set.is_nodrop = red_use_nodrop(q);
193 opt.set.qstats = &sch->qstats;
194 } else {
195 opt.command = TC_RED_DESTROY;
196 }
197
198 return dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_RED, &opt);
199 }
200
201 static void red_destroy(struct Qdisc *sch)
202 {
203 struct red_sched_data *q = qdisc_priv(sch);
204
205 del_timer_sync(&q->adapt_timer);
206 red_offload(sch, false);
207 qdisc_put(q->qdisc);
208 }
209
210 static const struct nla_policy red_policy[TCA_RED_MAX + 1] = {
211 [TCA_RED_UNSPEC] = { .strict_start_type = TCA_RED_FLAGS },
212 [TCA_RED_PARMS] = { .len = sizeof(struct tc_red_qopt) },
213 [TCA_RED_STAB] = { .len = RED_STAB_SIZE },
214 [TCA_RED_MAX_P] = { .type = NLA_U32 },
215 [TCA_RED_FLAGS] = { .type = NLA_BITFIELD32,
216 .validation_data = &red_supported_flags },
217 };
218
219 static int red_change(struct Qdisc *sch, struct nlattr *opt,
220 struct netlink_ext_ack *extack)
221 {
222 struct Qdisc *old_child = NULL, *child = NULL;
223 struct red_sched_data *q = qdisc_priv(sch);
224 struct nlattr *tb[TCA_RED_MAX + 1];
225 struct nla_bitfield32 flags_bf;
226 struct tc_red_qopt *ctl;
227 unsigned char userbits;
228 unsigned char flags;
229 int err;
230 u32 max_P;
231
232 if (opt == NULL)
233 return -EINVAL;
234
235 err = nla_parse_nested_deprecated(tb, TCA_RED_MAX, opt, red_policy,
236 NULL);
237 if (err < 0)
238 return err;
239
240 if (tb[TCA_RED_PARMS] == NULL ||
241 tb[TCA_RED_STAB] == NULL)
242 return -EINVAL;
243
244 max_P = tb[TCA_RED_MAX_P] ? nla_get_u32(tb[TCA_RED_MAX_P]) : 0;
245
246 ctl = nla_data(tb[TCA_RED_PARMS]);
247 if (!red_check_params(ctl->qth_min, ctl->qth_max, ctl->Wlog))
248 return -EINVAL;
249
250 err = red_get_flags(ctl->flags, TC_RED_HISTORIC_FLAGS,
251 tb[TCA_RED_FLAGS], red_supported_flags,
252 &flags_bf, &userbits, extack);
253 if (err)
254 return err;
255
256 if (ctl->limit > 0) {
257 child = fifo_create_dflt(sch, &bfifo_qdisc_ops, ctl->limit,
258 extack);
259 if (IS_ERR(child))
260 return PTR_ERR(child);
261
262 /* child is fifo, no need to check for noop_qdisc */
263 qdisc_hash_add(child, true);
264 }
265
266 sch_tree_lock(sch);
267
268 flags = (q->flags & ~flags_bf.selector) | flags_bf.value;
269 err = red_validate_flags(flags, extack);
270 if (err)
271 goto unlock_out;
272
273 q->flags = flags;
274 q->userbits = userbits;
275 q->limit = ctl->limit;
276 if (child) {
277 qdisc_tree_flush_backlog(q->qdisc);
278 old_child = q->qdisc;
279 q->qdisc = child;
280 }
281
282 red_set_parms(&q->parms,
283 ctl->qth_min, ctl->qth_max, ctl->Wlog,
284 ctl->Plog, ctl->Scell_log,
285 nla_data(tb[TCA_RED_STAB]),
286 max_P);
287 red_set_vars(&q->vars);
288
289 del_timer(&q->adapt_timer);
290 if (ctl->flags & TC_RED_ADAPTATIVE)
291 mod_timer(&q->adapt_timer, jiffies + HZ/2);
292
293 if (!q->qdisc->q.qlen)
294 red_start_of_idle_period(&q->vars);
295
296 sch_tree_unlock(sch);
297
298 red_offload(sch, true);
299
300 if (old_child)
301 qdisc_put(old_child);
302 return 0;
303
304 unlock_out:
305 sch_tree_unlock(sch);
306 if (child)
307 qdisc_put(child);
308 return err;
309 }
310
311 static inline void red_adaptative_timer(struct timer_list *t)
312 {
313 struct red_sched_data *q = from_timer(q, t, adapt_timer);
314 struct Qdisc *sch = q->sch;
315 spinlock_t *root_lock = qdisc_lock(qdisc_root_sleeping(sch));
316
317 spin_lock(root_lock);
318 red_adaptative_algo(&q->parms, &q->vars);
319 mod_timer(&q->adapt_timer, jiffies + HZ/2);
320 spin_unlock(root_lock);
321 }
322
323 static int red_init(struct Qdisc *sch, struct nlattr *opt,
324 struct netlink_ext_ack *extack)
325 {
326 struct red_sched_data *q = qdisc_priv(sch);
327
328 q->qdisc = &noop_qdisc;
329 q->sch = sch;
330 timer_setup(&q->adapt_timer, red_adaptative_timer, 0);
331 return red_change(sch, opt, extack);
332 }
333
334 static int red_dump_offload_stats(struct Qdisc *sch)
335 {
336 struct tc_red_qopt_offload hw_stats = {
337 .command = TC_RED_STATS,
338 .handle = sch->handle,
339 .parent = sch->parent,
340 {
341 .stats.bstats = &sch->bstats,
342 .stats.qstats = &sch->qstats,
343 },
344 };
345
346 return qdisc_offload_dump_helper(sch, TC_SETUP_QDISC_RED, &hw_stats);
347 }
348
349 static int red_dump(struct Qdisc *sch, struct sk_buff *skb)
350 {
351 struct red_sched_data *q = qdisc_priv(sch);
352 struct nlattr *opts = NULL;
353 struct tc_red_qopt opt = {
354 .limit = q->limit,
355 .flags = (q->flags & TC_RED_HISTORIC_FLAGS) |
356 q->userbits,
357 .qth_min = q->parms.qth_min >> q->parms.Wlog,
358 .qth_max = q->parms.qth_max >> q->parms.Wlog,
359 .Wlog = q->parms.Wlog,
360 .Plog = q->parms.Plog,
361 .Scell_log = q->parms.Scell_log,
362 };
363 int err;
364
365 err = red_dump_offload_stats(sch);
366 if (err)
367 goto nla_put_failure;
368
369 opts = nla_nest_start_noflag(skb, TCA_OPTIONS);
370 if (opts == NULL)
371 goto nla_put_failure;
372 if (nla_put(skb, TCA_RED_PARMS, sizeof(opt), &opt) ||
373 nla_put_u32(skb, TCA_RED_MAX_P, q->parms.max_P) ||
374 nla_put_bitfield32(skb, TCA_RED_FLAGS,
375 q->flags, red_supported_flags))
376 goto nla_put_failure;
377 return nla_nest_end(skb, opts);
378
379 nla_put_failure:
380 nla_nest_cancel(skb, opts);
381 return -EMSGSIZE;
382 }
383
384 static int red_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
385 {
386 struct red_sched_data *q = qdisc_priv(sch);
387 struct net_device *dev = qdisc_dev(sch);
388 struct tc_red_xstats st = {0};
389
390 if (sch->flags & TCQ_F_OFFLOADED) {
391 struct tc_red_qopt_offload hw_stats_request = {
392 .command = TC_RED_XSTATS,
393 .handle = sch->handle,
394 .parent = sch->parent,
395 {
396 .xstats = &q->stats,
397 },
398 };
399 dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_RED,
400 &hw_stats_request);
401 }
402 st.early = q->stats.prob_drop + q->stats.forced_drop;
403 st.pdrop = q->stats.pdrop;
404 st.other = q->stats.other;
405 st.marked = q->stats.prob_mark + q->stats.forced_mark;
406
407 return gnet_stats_copy_app(d, &st, sizeof(st));
408 }
409
410 static int red_dump_class(struct Qdisc *sch, unsigned long cl,
411 struct sk_buff *skb, struct tcmsg *tcm)
412 {
413 struct red_sched_data *q = qdisc_priv(sch);
414
415 tcm->tcm_handle |= TC_H_MIN(1);
416 tcm->tcm_info = q->qdisc->handle;
417 return 0;
418 }
419
420 static void red_graft_offload(struct Qdisc *sch,
421 struct Qdisc *new, struct Qdisc *old,
422 struct netlink_ext_ack *extack)
423 {
424 struct tc_red_qopt_offload graft_offload = {
425 .handle = sch->handle,
426 .parent = sch->parent,
427 .child_handle = new->handle,
428 .command = TC_RED_GRAFT,
429 };
430
431 qdisc_offload_graft_helper(qdisc_dev(sch), sch, new, old,
432 TC_SETUP_QDISC_RED, &graft_offload, extack);
433 }
434
435 static int red_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
436 struct Qdisc **old, struct netlink_ext_ack *extack)
437 {
438 struct red_sched_data *q = qdisc_priv(sch);
439
440 if (new == NULL)
441 new = &noop_qdisc;
442
443 *old = qdisc_replace(sch, new, &q->qdisc);
444
445 red_graft_offload(sch, new, *old, extack);
446 return 0;
447 }
448
449 static struct Qdisc *red_leaf(struct Qdisc *sch, unsigned long arg)
450 {
451 struct red_sched_data *q = qdisc_priv(sch);
452 return q->qdisc;
453 }
454
455 static unsigned long red_find(struct Qdisc *sch, u32 classid)
456 {
457 return 1;
458 }
459
460 static void red_walk(struct Qdisc *sch, struct qdisc_walker *walker)
461 {
462 if (!walker->stop) {
463 if (walker->count >= walker->skip)
464 if (walker->fn(sch, 1, walker) < 0) {
465 walker->stop = 1;
466 return;
467 }
468 walker->count++;
469 }
470 }
471
472 static const struct Qdisc_class_ops red_class_ops = {
473 .graft = red_graft,
474 .leaf = red_leaf,
475 .find = red_find,
476 .walk = red_walk,
477 .dump = red_dump_class,
478 };
479
480 static struct Qdisc_ops red_qdisc_ops __read_mostly = {
481 .id = "red",
482 .priv_size = sizeof(struct red_sched_data),
483 .cl_ops = &red_class_ops,
484 .enqueue = red_enqueue,
485 .dequeue = red_dequeue,
486 .peek = red_peek,
487 .init = red_init,
488 .reset = red_reset,
489 .destroy = red_destroy,
490 .change = red_change,
491 .dump = red_dump,
492 .dump_stats = red_dump_stats,
493 .owner = THIS_MODULE,
494 };
495
496 static int __init red_module_init(void)
497 {
498 return register_qdisc(&red_qdisc_ops);
499 }
500
501 static void __exit red_module_exit(void)
502 {
503 unregister_qdisc(&red_qdisc_ops);
504 }
505
506 module_init(red_module_init)
507 module_exit(red_module_exit)
508
509 MODULE_LICENSE("GPL");
Linux with added FPC-III support