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Committer: Michael Beasley <mike@snafu.setup>
[mikesnafu-overlay.git] / net / sched / sch_gred.c
blob3a9d226ff1e41eba0492168f3166e4a9a3cb8f15
1 /*
2 * net/sched/sch_gred.c Generic Random Early Detection queue.
3 *
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License
7 * as published by the Free Software Foundation; either version
8 * 2 of the License, or (at your option) any later version.
9 *
10 * Authors: J Hadi Salim (hadi@cyberus.ca) 1998-2002
11 *
12 * 991129: - Bug fix with grio mode
13 * - a better sing. AvgQ mode with Grio(WRED)
14 * - A finer grained VQ dequeue based on sugestion
15 * from Ren Liu
16 * - More error checks
17 *
18 * For all the glorious comments look at include/net/red.h
19 */
20
21 #include <linux/module.h>
22 #include <linux/types.h>
23 #include <linux/kernel.h>
24 #include <linux/skbuff.h>
25 #include <net/pkt_sched.h>
26 #include <net/red.h>
27
28 #define GRED_DEF_PRIO (MAX_DPs / 2)
29 #define GRED_VQ_MASK (MAX_DPs - 1)
30
31 struct gred_sched_data;
32 struct gred_sched;
33
34 struct gred_sched_data
35 {
36 u32 limit; /* HARD maximal queue length */
37 u32 DP; /* the drop pramaters */
38 u32 bytesin; /* bytes seen on virtualQ so far*/
39 u32 packetsin; /* packets seen on virtualQ so far*/
40 u32 backlog; /* bytes on the virtualQ */
41 u8 prio; /* the prio of this vq */
42
43 struct red_parms parms;
44 struct red_stats stats;
45 };
46
47 enum {
48 GRED_WRED_MODE = 1,
49 GRED_RIO_MODE,
50 };
51
52 struct gred_sched
53 {
54 struct gred_sched_data *tab[MAX_DPs];
55 unsigned long flags;
56 u32 red_flags;
57 u32 DPs;
58 u32 def;
59 struct red_parms wred_set;
60 };
61
62 static inline int gred_wred_mode(struct gred_sched *table)
63 {
64 return test_bit(GRED_WRED_MODE, &table->flags);
65 }
66
67 static inline void gred_enable_wred_mode(struct gred_sched *table)
68 {
69 __set_bit(GRED_WRED_MODE, &table->flags);
70 }
71
72 static inline void gred_disable_wred_mode(struct gred_sched *table)
73 {
74 __clear_bit(GRED_WRED_MODE, &table->flags);
75 }
76
77 static inline int gred_rio_mode(struct gred_sched *table)
78 {
79 return test_bit(GRED_RIO_MODE, &table->flags);
80 }
81
82 static inline void gred_enable_rio_mode(struct gred_sched *table)
83 {
84 __set_bit(GRED_RIO_MODE, &table->flags);
85 }
86
87 static inline void gred_disable_rio_mode(struct gred_sched *table)
88 {
89 __clear_bit(GRED_RIO_MODE, &table->flags);
90 }
91
92 static inline int gred_wred_mode_check(struct Qdisc *sch)
93 {
94 struct gred_sched *table = qdisc_priv(sch);
95 int i;
96
97 /* Really ugly O(n^2) but shouldn't be necessary too frequent. */
98 for (i = 0; i < table->DPs; i++) {
99 struct gred_sched_data *q = table->tab[i];
100 int n;
101
102 if (q == NULL)
103 continue;
104
105 for (n = 0; n < table->DPs; n++)
106 if (table->tab[n] && table->tab[n] != q &&
107 table->tab[n]->prio == q->prio)
108 return 1;
109 }
110
111 return 0;
112 }
113
114 static inline unsigned int gred_backlog(struct gred_sched *table,
115 struct gred_sched_data *q,
116 struct Qdisc *sch)
117 {
118 if (gred_wred_mode(table))
119 return sch->qstats.backlog;
120 else
121 return q->backlog;
122 }
123
124 static inline u16 tc_index_to_dp(struct sk_buff *skb)
125 {
126 return skb->tc_index & GRED_VQ_MASK;
127 }
128
129 static inline void gred_load_wred_set(struct gred_sched *table,
130 struct gred_sched_data *q)
131 {
132 q->parms.qavg = table->wred_set.qavg;
133 q->parms.qidlestart = table->wred_set.qidlestart;
134 }
135
136 static inline void gred_store_wred_set(struct gred_sched *table,
137 struct gred_sched_data *q)
138 {
139 table->wred_set.qavg = q->parms.qavg;
140 }
141
142 static inline int gred_use_ecn(struct gred_sched *t)
143 {
144 return t->red_flags & TC_RED_ECN;
145 }
146
147 static inline int gred_use_harddrop(struct gred_sched *t)
148 {
149 return t->red_flags & TC_RED_HARDDROP;
150 }
151
152 static int gred_enqueue(struct sk_buff *skb, struct Qdisc* sch)
153 {
154 struct gred_sched_data *q=NULL;
155 struct gred_sched *t= qdisc_priv(sch);
156 unsigned long qavg = 0;
157 u16 dp = tc_index_to_dp(skb);
158
159 if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
160 dp = t->def;
161
162 if ((q = t->tab[dp]) == NULL) {
163 /* Pass through packets not assigned to a DP
164 * if no default DP has been configured. This
165 * allows for DP flows to be left untouched.
166 */
167 if (skb_queue_len(&sch->q) < sch->dev->tx_queue_len)
168 return qdisc_enqueue_tail(skb, sch);
169 else
170 goto drop;
171 }
172
173 /* fix tc_index? --could be controvesial but needed for
174 requeueing */
175 skb->tc_index = (skb->tc_index & ~GRED_VQ_MASK) | dp;
176 }
177
178 /* sum up all the qaves of prios <= to ours to get the new qave */
179 if (!gred_wred_mode(t) && gred_rio_mode(t)) {
180 int i;
181
182 for (i = 0; i < t->DPs; i++) {
183 if (t->tab[i] && t->tab[i]->prio < q->prio &&
184 !red_is_idling(&t->tab[i]->parms))
185 qavg +=t->tab[i]->parms.qavg;
186 }
187
188 }
189
190 q->packetsin++;
191 q->bytesin += skb->len;
192
193 if (gred_wred_mode(t))
194 gred_load_wred_set(t, q);
195
196 q->parms.qavg = red_calc_qavg(&q->parms, gred_backlog(t, q, sch));
197
198 if (red_is_idling(&q->parms))
199 red_end_of_idle_period(&q->parms);
200
201 if (gred_wred_mode(t))
202 gred_store_wred_set(t, q);
203
204 switch (red_action(&q->parms, q->parms.qavg + qavg)) {
205 case RED_DONT_MARK:
206 break;
207
208 case RED_PROB_MARK:
209 sch->qstats.overlimits++;
210 if (!gred_use_ecn(t) || !INET_ECN_set_ce(skb)) {
211 q->stats.prob_drop++;
212 goto congestion_drop;
213 }
214
215 q->stats.prob_mark++;
216 break;
217
218 case RED_HARD_MARK:
219 sch->qstats.overlimits++;
220 if (gred_use_harddrop(t) || !gred_use_ecn(t) ||
221 !INET_ECN_set_ce(skb)) {
222 q->stats.forced_drop++;
223 goto congestion_drop;
224 }
225 q->stats.forced_mark++;
226 break;
227 }
228
229 if (q->backlog + skb->len <= q->limit) {
230 q->backlog += skb->len;
231 return qdisc_enqueue_tail(skb, sch);
232 }
233
234 q->stats.pdrop++;
235 drop:
236 return qdisc_drop(skb, sch);
237
238 congestion_drop:
239 qdisc_drop(skb, sch);
240 return NET_XMIT_CN;
241 }
242
243 static int gred_requeue(struct sk_buff *skb, struct Qdisc* sch)
244 {
245 struct gred_sched *t = qdisc_priv(sch);
246 struct gred_sched_data *q;
247 u16 dp = tc_index_to_dp(skb);
248
249 if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
250 if (net_ratelimit())
251 printk(KERN_WARNING "GRED: Unable to relocate VQ 0x%x "
252 "for requeue, screwing up backlog.\n",
253 tc_index_to_dp(skb));
254 } else {
255 if (red_is_idling(&q->parms))
256 red_end_of_idle_period(&q->parms);
257 q->backlog += skb->len;
258 }
259
260 return qdisc_requeue(skb, sch);
261 }
262
263 static struct sk_buff *gred_dequeue(struct Qdisc* sch)
264 {
265 struct sk_buff *skb;
266 struct gred_sched *t = qdisc_priv(sch);
267
268 skb = qdisc_dequeue_head(sch);
269
270 if (skb) {
271 struct gred_sched_data *q;
272 u16 dp = tc_index_to_dp(skb);
273
274 if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
275 if (net_ratelimit())
276 printk(KERN_WARNING "GRED: Unable to relocate "
277 "VQ 0x%x after dequeue, screwing up "
278 "backlog.\n", tc_index_to_dp(skb));
279 } else {
280 q->backlog -= skb->len;
281
282 if (!q->backlog && !gred_wred_mode(t))
283 red_start_of_idle_period(&q->parms);
284 }
285
286 return skb;
287 }
288
289 if (gred_wred_mode(t) && !red_is_idling(&t->wred_set))
290 red_start_of_idle_period(&t->wred_set);
291
292 return NULL;
293 }
294
295 static unsigned int gred_drop(struct Qdisc* sch)
296 {
297 struct sk_buff *skb;
298 struct gred_sched *t = qdisc_priv(sch);
299
300 skb = qdisc_dequeue_tail(sch);
301 if (skb) {
302 unsigned int len = skb->len;
303 struct gred_sched_data *q;
304 u16 dp = tc_index_to_dp(skb);
305
306 if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
307 if (net_ratelimit())
308 printk(KERN_WARNING "GRED: Unable to relocate "
309 "VQ 0x%x while dropping, screwing up "
310 "backlog.\n", tc_index_to_dp(skb));
311 } else {
312 q->backlog -= len;
313 q->stats.other++;
314
315 if (!q->backlog && !gred_wred_mode(t))
316 red_start_of_idle_period(&q->parms);
317 }
318
319 qdisc_drop(skb, sch);
320 return len;
321 }
322
323 if (gred_wred_mode(t) && !red_is_idling(&t->wred_set))
324 red_start_of_idle_period(&t->wred_set);
325
326 return 0;
327
328 }
329
330 static void gred_reset(struct Qdisc* sch)
331 {
332 int i;
333 struct gred_sched *t = qdisc_priv(sch);
334
335 qdisc_reset_queue(sch);
336
337 for (i = 0; i < t->DPs; i++) {
338 struct gred_sched_data *q = t->tab[i];
339
340 if (!q)
341 continue;
342
343 red_restart(&q->parms);
344 q->backlog = 0;
345 }
346 }
347
348 static inline void gred_destroy_vq(struct gred_sched_data *q)
349 {
350 kfree(q);
351 }
352
353 static inline int gred_change_table_def(struct Qdisc *sch, struct nlattr *dps)
354 {
355 struct gred_sched *table = qdisc_priv(sch);
356 struct tc_gred_sopt *sopt;
357 int i;
358
359 if (dps == NULL)
360 return -EINVAL;
361
362 sopt = nla_data(dps);
363
364 if (sopt->DPs > MAX_DPs || sopt->DPs == 0 || sopt->def_DP >= sopt->DPs)
365 return -EINVAL;
366
367 sch_tree_lock(sch);
368 table->DPs = sopt->DPs;
369 table->def = sopt->def_DP;
370 table->red_flags = sopt->flags;
371
372 /*
373 * Every entry point to GRED is synchronized with the above code
374 * and the DP is checked against DPs, i.e. shadowed VQs can no
375 * longer be found so we can unlock right here.
376 */
377 sch_tree_unlock(sch);
378
379 if (sopt->grio) {
380 gred_enable_rio_mode(table);
381 gred_disable_wred_mode(table);
382 if (gred_wred_mode_check(sch))
383 gred_enable_wred_mode(table);
384 } else {
385 gred_disable_rio_mode(table);
386 gred_disable_wred_mode(table);
387 }
388
389 for (i = table->DPs; i < MAX_DPs; i++) {
390 if (table->tab[i]) {
391 printk(KERN_WARNING "GRED: Warning: Destroying "
392 "shadowed VQ 0x%x\n", i);
393 gred_destroy_vq(table->tab[i]);
394 table->tab[i] = NULL;
395 }
396 }
397
398 return 0;
399 }
400
401 static inline int gred_change_vq(struct Qdisc *sch, int dp,
402 struct tc_gred_qopt *ctl, int prio, u8 *stab)
403 {
404 struct gred_sched *table = qdisc_priv(sch);
405 struct gred_sched_data *q;
406
407 if (table->tab[dp] == NULL) {
408 table->tab[dp] = kzalloc(sizeof(*q), GFP_KERNEL);
409 if (table->tab[dp] == NULL)
410 return -ENOMEM;
411 }
412
413 q = table->tab[dp];
414 q->DP = dp;
415 q->prio = prio;
416 q->limit = ctl->limit;
417
418 if (q->backlog == 0)
419 red_end_of_idle_period(&q->parms);
420
421 red_set_parms(&q->parms,
422 ctl->qth_min, ctl->qth_max, ctl->Wlog, ctl->Plog,
423 ctl->Scell_log, stab);
424
425 return 0;
426 }
427
428 static const struct nla_policy gred_policy[TCA_GRED_MAX + 1] = {
429 [TCA_GRED_PARMS] = { .len = sizeof(struct tc_gred_qopt) },
430 [TCA_GRED_STAB] = { .len = 256 },
431 [TCA_GRED_DPS] = { .len = sizeof(struct tc_gred_sopt) },
432 };
433
434 static int gred_change(struct Qdisc *sch, struct nlattr *opt)
435 {
436 struct gred_sched *table = qdisc_priv(sch);
437 struct tc_gred_qopt *ctl;
438 struct nlattr *tb[TCA_GRED_MAX + 1];
439 int err, prio = GRED_DEF_PRIO;
440 u8 *stab;
441
442 if (opt == NULL)
443 return -EINVAL;
444
445 err = nla_parse_nested(tb, TCA_GRED_MAX, opt, gred_policy);
446 if (err < 0)
447 return err;
448
449 if (tb[TCA_GRED_PARMS] == NULL && tb[TCA_GRED_STAB] == NULL)
450 return gred_change_table_def(sch, opt);
451
452 if (tb[TCA_GRED_PARMS] == NULL ||
453 tb[TCA_GRED_STAB] == NULL)
454 return -EINVAL;
455
456 err = -EINVAL;
457 ctl = nla_data(tb[TCA_GRED_PARMS]);
458 stab = nla_data(tb[TCA_GRED_STAB]);
459
460 if (ctl->DP >= table->DPs)
461 goto errout;
462
463 if (gred_rio_mode(table)) {
464 if (ctl->prio == 0) {
465 int def_prio = GRED_DEF_PRIO;
466
467 if (table->tab[table->def])
468 def_prio = table->tab[table->def]->prio;
469
470 printk(KERN_DEBUG "GRED: DP %u does not have a prio "
471 "setting default to %d\n", ctl->DP, def_prio);
472
473 prio = def_prio;
474 } else
475 prio = ctl->prio;
476 }
477
478 sch_tree_lock(sch);
479
480 err = gred_change_vq(sch, ctl->DP, ctl, prio, stab);
481 if (err < 0)
482 goto errout_locked;
483
484 if (gred_rio_mode(table)) {
485 gred_disable_wred_mode(table);
486 if (gred_wred_mode_check(sch))
487 gred_enable_wred_mode(table);
488 }
489
490 err = 0;
491
492 errout_locked:
493 sch_tree_unlock(sch);
494 errout:
495 return err;
496 }
497
498 static int gred_init(struct Qdisc *sch, struct nlattr *opt)
499 {
500 struct nlattr *tb[TCA_GRED_MAX + 1];
501 int err;
502
503 if (opt == NULL)
504 return -EINVAL;
505
506 err = nla_parse_nested(tb, TCA_GRED_MAX, opt, gred_policy);
507 if (err < 0)
508 return err;
509
510 if (tb[TCA_GRED_PARMS] || tb[TCA_GRED_STAB])
511 return -EINVAL;
512
513 return gred_change_table_def(sch, tb[TCA_GRED_DPS]);
514 }
515
516 static int gred_dump(struct Qdisc *sch, struct sk_buff *skb)
517 {
518 struct gred_sched *table = qdisc_priv(sch);
519 struct nlattr *parms, *opts = NULL;
520 int i;
521 struct tc_gred_sopt sopt = {
522 .DPs = table->DPs,
523 .def_DP = table->def,
524 .grio = gred_rio_mode(table),
525 .flags = table->red_flags,
526 };
527
528 opts = nla_nest_start(skb, TCA_OPTIONS);
529 if (opts == NULL)
530 goto nla_put_failure;
531 NLA_PUT(skb, TCA_GRED_DPS, sizeof(sopt), &sopt);
532 parms = nla_nest_start(skb, TCA_GRED_PARMS);
533 if (parms == NULL)
534 goto nla_put_failure;
535
536 for (i = 0; i < MAX_DPs; i++) {
537 struct gred_sched_data *q = table->tab[i];
538 struct tc_gred_qopt opt;
539
540 memset(&opt, 0, sizeof(opt));
541
542 if (!q) {
543 /* hack -- fix at some point with proper message
544 This is how we indicate to tc that there is no VQ
545 at this DP */
546
547 opt.DP = MAX_DPs + i;
548 goto append_opt;
549 }
550
551 opt.limit = q->limit;
552 opt.DP = q->DP;
553 opt.backlog = q->backlog;
554 opt.prio = q->prio;
555 opt.qth_min = q->parms.qth_min >> q->parms.Wlog;
556 opt.qth_max = q->parms.qth_max >> q->parms.Wlog;
557 opt.Wlog = q->parms.Wlog;
558 opt.Plog = q->parms.Plog;
559 opt.Scell_log = q->parms.Scell_log;
560 opt.other = q->stats.other;
561 opt.early = q->stats.prob_drop;
562 opt.forced = q->stats.forced_drop;
563 opt.pdrop = q->stats.pdrop;
564 opt.packets = q->packetsin;
565 opt.bytesin = q->bytesin;
566
567 if (gred_wred_mode(table)) {
568 q->parms.qidlestart =
569 table->tab[table->def]->parms.qidlestart;
570 q->parms.qavg = table->tab[table->def]->parms.qavg;
571 }
572
573 opt.qave = red_calc_qavg(&q->parms, q->parms.qavg);
574
575 append_opt:
576 if (nla_append(skb, sizeof(opt), &opt) < 0)
577 goto nla_put_failure;
578 }
579
580 nla_nest_end(skb, parms);
581
582 return nla_nest_end(skb, opts);
583
584 nla_put_failure:
585 return nla_nest_cancel(skb, opts);
586 }
587
588 static void gred_destroy(struct Qdisc *sch)
589 {
590 struct gred_sched *table = qdisc_priv(sch);
591 int i;
592
593 for (i = 0; i < table->DPs; i++) {
594 if (table->tab[i])
595 gred_destroy_vq(table->tab[i]);
596 }
597 }
598
599 static struct Qdisc_ops gred_qdisc_ops __read_mostly = {
600 .id = "gred",
601 .priv_size = sizeof(struct gred_sched),
602 .enqueue = gred_enqueue,
603 .dequeue = gred_dequeue,
604 .requeue = gred_requeue,
605 .drop = gred_drop,
606 .init = gred_init,
607 .reset = gred_reset,
608 .destroy = gred_destroy,
609 .change = gred_change,
610 .dump = gred_dump,
611 .owner = THIS_MODULE,
612 };
613
614 static int __init gred_module_init(void)
615 {
616 return register_qdisc(&gred_qdisc_ops);
617 }
618
619 static void __exit gred_module_exit(void)
620 {
621 unregister_qdisc(&gred_qdisc_ops);
622 }
623
624 module_init(gred_module_init)
625 module_exit(gred_module_exit)
626
627 MODULE_LICENSE("GPL");
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