1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * net/sched/sch_sfb.c Stochastic Fair Blue
4 *
5 * Copyright (c) 2008-2011 Juliusz Chroboczek <jch@pps.jussieu.fr>
6 * Copyright (c) 2011 Eric Dumazet <eric.dumazet@gmail.com>
7 *
8 * W. Feng, D. Kandlur, D. Saha, K. Shin. Blue:
9 * A New Class of Active Queue Management Algorithms.
10 * U. Michigan CSE-TR-387-99, April 1999.
11 *
12 * http://www.thefengs.com/wuchang/blue/CSE-TR-387-99.pdf
13 */
14
15 #include <linux/module.h>
16 #include <linux/types.h>
17 #include <linux/kernel.h>
18 #include <linux/errno.h>
19 #include <linux/skbuff.h>
20 #include <linux/random.h>
21 #include <linux/siphash.h>
22 #include <net/ip.h>
23 #include <net/pkt_sched.h>
24 #include <net/pkt_cls.h>
25 #include <net/inet_ecn.h>
26
27 /*
28 * SFB uses two B[l][n] : L x N arrays of bins (L levels, N bins per level)
29 * This implementation uses L = 8 and N = 16
30 * This permits us to split one 32bit hash (provided per packet by rxhash or
31 * external classifier) into 8 subhashes of 4 bits.
32 */
33 #define SFB_BUCKET_SHIFT 4
34 #define SFB_NUMBUCKETS (1 << SFB_BUCKET_SHIFT) /* N bins per Level */
35 #define SFB_BUCKET_MASK (SFB_NUMBUCKETS - 1)
36 #define SFB_LEVELS (32 / SFB_BUCKET_SHIFT) /* L */
37
38 /* SFB algo uses a virtual queue, named "bin" */
39 struct sfb_bucket {
40 u16 qlen; /* length of virtual queue */
41 u16 p_mark; /* marking probability */
42 };
43
44 /* We use a double buffering right before hash change
45 * (Section 4.4 of SFB reference : moving hash functions)
46 */
47 struct sfb_bins {
48 siphash_key_t perturbation; /* siphash key */
49 struct sfb_bucket bins[SFB_LEVELS][SFB_NUMBUCKETS];
50 };
51
52 struct sfb_sched_data {
53 struct Qdisc *qdisc;
54 struct tcf_proto __rcu *filter_list;
55 struct tcf_block *block;
56 unsigned long rehash_interval;
57 unsigned long warmup_time; /* double buffering warmup time in jiffies */
58 u32 max;
59 u32 bin_size; /* maximum queue length per bin */
60 u32 increment; /* d1 */
61 u32 decrement; /* d2 */
62 u32 limit; /* HARD maximal queue length */
63 u32 penalty_rate;
64 u32 penalty_burst;
65 u32 tokens_avail;
66 unsigned long rehash_time;
67 unsigned long token_time;
68
69 u8 slot; /* current active bins (0 or 1) */
70 bool double_buffering;
71 struct sfb_bins bins[2];
72
73 struct {
74 u32 earlydrop;
75 u32 penaltydrop;
76 u32 bucketdrop;
77 u32 queuedrop;
78 u32 childdrop; /* drops in child qdisc */
79 u32 marked; /* ECN mark */
80 } stats;
81 };
82
83 /*
84 * Each queued skb might be hashed on one or two bins
85 * We store in skb_cb the two hash values.
86 * (A zero value means double buffering was not used)
87 */
88 struct sfb_skb_cb {
89 u32 hashes[2];
90 };
91
92 static inline struct sfb_skb_cb *sfb_skb_cb(const struct sk_buff *skb)
93 {
94 qdisc_cb_private_validate(skb, sizeof(struct sfb_skb_cb));
95 return (struct sfb_skb_cb *)qdisc_skb_cb(skb)->data;
96 }
97
98 /*
99 * If using 'internal' SFB flow classifier, hash comes from skb rxhash
100 * If using external classifier, hash comes from the classid.
101 */
102 static u32 sfb_hash(const struct sk_buff *skb, u32 slot)
103 {
104 return sfb_skb_cb(skb)->hashes[slot];
105 }
106
107 /* Probabilities are coded as Q0.16 fixed-point values,
108 * with 0xFFFF representing 65535/65536 (almost 1.0)
109 * Addition and subtraction are saturating in [0, 65535]
110 */
111 static u32 prob_plus(u32 p1, u32 p2)
112 {
113 u32 res = p1 + p2;
114
115 return min_t(u32, res, SFB_MAX_PROB);
116 }
117
118 static u32 prob_minus(u32 p1, u32 p2)
119 {
120 return p1 > p2 ? p1 - p2 : 0;
121 }
122
123 static void increment_one_qlen(u32 sfbhash, u32 slot, struct sfb_sched_data *q)
124 {
125 int i;
126 struct sfb_bucket *b = &q->bins[slot].bins[0][0];
127
128 for (i = 0; i < SFB_LEVELS; i++) {
129 u32 hash = sfbhash & SFB_BUCKET_MASK;
130
131 sfbhash >>= SFB_BUCKET_SHIFT;
132 if (b[hash].qlen < 0xFFFF)
133 b[hash].qlen++;
134 b += SFB_NUMBUCKETS; /* next level */
135 }
136 }
137
138 static void increment_qlen(const struct sfb_skb_cb *cb, struct sfb_sched_data *q)
139 {
140 u32 sfbhash;
141
142 sfbhash = cb->hashes[0];
143 if (sfbhash)
144 increment_one_qlen(sfbhash, 0, q);
145
146 sfbhash = cb->hashes[1];
147 if (sfbhash)
148 increment_one_qlen(sfbhash, 1, q);
149 }
150
151 static void decrement_one_qlen(u32 sfbhash, u32 slot,
152 struct sfb_sched_data *q)
153 {
154 int i;
155 struct sfb_bucket *b = &q->bins[slot].bins[0][0];
156
157 for (i = 0; i < SFB_LEVELS; i++) {
158 u32 hash = sfbhash & SFB_BUCKET_MASK;
159
160 sfbhash >>= SFB_BUCKET_SHIFT;
161 if (b[hash].qlen > 0)
162 b[hash].qlen--;
163 b += SFB_NUMBUCKETS; /* next level */
164 }
165 }
166
167 static void decrement_qlen(const struct sk_buff *skb, struct sfb_sched_data *q)
168 {
169 u32 sfbhash;
170
171 sfbhash = sfb_hash(skb, 0);
172 if (sfbhash)
173 decrement_one_qlen(sfbhash, 0, q);
174
175 sfbhash = sfb_hash(skb, 1);
176 if (sfbhash)
177 decrement_one_qlen(sfbhash, 1, q);
178 }
179
180 static void decrement_prob(struct sfb_bucket *b, struct sfb_sched_data *q)
181 {
182 b->p_mark = prob_minus(b->p_mark, q->decrement);
183 }
184
185 static void increment_prob(struct sfb_bucket *b, struct sfb_sched_data *q)
186 {
187 b->p_mark = prob_plus(b->p_mark, q->increment);
188 }
189
190 static void sfb_zero_all_buckets(struct sfb_sched_data *q)
191 {
192 memset(&q->bins, 0, sizeof(q->bins));
193 }
194
195 /*
196 * compute max qlen, max p_mark, and avg p_mark
197 */
198 static u32 sfb_compute_qlen(u32 *prob_r, u32 *avgpm_r, const struct sfb_sched_data *q)
199 {
200 int i;
201 u32 qlen = 0, prob = 0, totalpm = 0;
202 const struct sfb_bucket *b = &q->bins[q->slot].bins[0][0];
203
204 for (i = 0; i < SFB_LEVELS * SFB_NUMBUCKETS; i++) {
205 if (qlen < b->qlen)
206 qlen = b->qlen;
207 totalpm += b->p_mark;
208 if (prob < b->p_mark)
209 prob = b->p_mark;
210 b++;
211 }
212 *prob_r = prob;
213 *avgpm_r = totalpm / (SFB_LEVELS * SFB_NUMBUCKETS);
214 return qlen;
215 }
216
217
218 static void sfb_init_perturbation(u32 slot, struct sfb_sched_data *q)
219 {
220 get_random_bytes(&q->bins[slot].perturbation,
221 sizeof(q->bins[slot].perturbation));
222 }
223
224 static void sfb_swap_slot(struct sfb_sched_data *q)
225 {
226 sfb_init_perturbation(q->slot, q);
227 q->slot ^= 1;
228 q->double_buffering = false;
229 }
230
231 /* Non elastic flows are allowed to use part of the bandwidth, expressed
232 * in "penalty_rate" packets per second, with "penalty_burst" burst
233 */
234 static bool sfb_rate_limit(struct sk_buff *skb, struct sfb_sched_data *q)
235 {
236 if (q->penalty_rate == 0 || q->penalty_burst == 0)
237 return true;
238
239 if (q->tokens_avail < 1) {
240 unsigned long age = min(10UL * HZ, jiffies - q->token_time);
241
242 q->tokens_avail = (age * q->penalty_rate) / HZ;
243 if (q->tokens_avail > q->penalty_burst)
244 q->tokens_avail = q->penalty_burst;
245 q->token_time = jiffies;
246 if (q->tokens_avail < 1)
247 return true;
248 }
249
250 q->tokens_avail--;
251 return false;
252 }
253
254 static bool sfb_classify(struct sk_buff *skb, struct tcf_proto *fl,
255 int *qerr, u32 *salt)
256 {
257 struct tcf_result res;
258 int result;
259
260 result = tcf_classify(skb, NULL, fl, &res, false);
261 if (result >= 0) {
262 #ifdef CONFIG_NET_CLS_ACT
263 switch (result) {
264 case TC_ACT_STOLEN:
265 case TC_ACT_QUEUED:
266 case TC_ACT_TRAP:
267 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
268 fallthrough;
269 case TC_ACT_SHOT:
270 return false;
271 }
272 #endif
273 *salt = TC_H_MIN(res.classid);
274 return true;
275 }
276 return false;
277 }
278
279 static int sfb_enqueue(struct sk_buff *skb, struct Qdisc *sch,
280 struct sk_buff **to_free)
281 {
282
283 struct sfb_sched_data *q = qdisc_priv(sch);
284 unsigned int len = qdisc_pkt_len(skb);
285 struct Qdisc *child = q->qdisc;
286 struct tcf_proto *fl;
287 struct sfb_skb_cb cb;
288 int i;
289 u32 p_min = ~0;
290 u32 minqlen = ~0;
291 u32 r, sfbhash;
292 u32 slot = q->slot;
293 int ret = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
294
295 if (unlikely(sch->q.qlen >= q->limit)) {
296 qdisc_qstats_overlimit(sch);
297 q->stats.queuedrop++;
298 goto drop;
299 }
300
301 if (q->rehash_interval > 0) {
302 unsigned long limit = q->rehash_time + q->rehash_interval;
303
304 if (unlikely(time_after(jiffies, limit))) {
305 sfb_swap_slot(q);
306 q->rehash_time = jiffies;
307 } else if (unlikely(!q->double_buffering && q->warmup_time > 0 &&
308 time_after(jiffies, limit - q->warmup_time))) {
309 q->double_buffering = true;
310 }
311 }
312
313 fl = rcu_dereference_bh(q->filter_list);
314 if (fl) {
315 u32 salt;
316
317 /* If using external classifiers, get result and record it. */
318 if (!sfb_classify(skb, fl, &ret, &salt))
319 goto other_drop;
320 sfbhash = siphash_1u32(salt, &q->bins[slot].perturbation);
321 } else {
322 sfbhash = skb_get_hash_perturb(skb, &q->bins[slot].perturbation);
323 }
324
325
326 if (!sfbhash)
327 sfbhash = 1;
328 sfb_skb_cb(skb)->hashes[slot] = sfbhash;
329
330 for (i = 0; i < SFB_LEVELS; i++) {
331 u32 hash = sfbhash & SFB_BUCKET_MASK;
332 struct sfb_bucket *b = &q->bins[slot].bins[i][hash];
333
334 sfbhash >>= SFB_BUCKET_SHIFT;
335 if (b->qlen == 0)
336 decrement_prob(b, q);
337 else if (b->qlen >= q->bin_size)
338 increment_prob(b, q);
339 if (minqlen > b->qlen)
340 minqlen = b->qlen;
341 if (p_min > b->p_mark)
342 p_min = b->p_mark;
343 }
344
345 slot ^= 1;
346 sfb_skb_cb(skb)->hashes[slot] = 0;
347
348 if (unlikely(minqlen >= q->max)) {
349 qdisc_qstats_overlimit(sch);
350 q->stats.bucketdrop++;
351 goto drop;
352 }
353
354 if (unlikely(p_min >= SFB_MAX_PROB)) {
355 /* Inelastic flow */
356 if (q->double_buffering) {
357 sfbhash = skb_get_hash_perturb(skb,
358 &q->bins[slot].perturbation);
359 if (!sfbhash)
360 sfbhash = 1;
361 sfb_skb_cb(skb)->hashes[slot] = sfbhash;
362
363 for (i = 0; i < SFB_LEVELS; i++) {
364 u32 hash = sfbhash & SFB_BUCKET_MASK;
365 struct sfb_bucket *b = &q->bins[slot].bins[i][hash];
366
367 sfbhash >>= SFB_BUCKET_SHIFT;
368 if (b->qlen == 0)
369 decrement_prob(b, q);
370 else if (b->qlen >= q->bin_size)
371 increment_prob(b, q);
372 }
373 }
374 if (sfb_rate_limit(skb, q)) {
375 qdisc_qstats_overlimit(sch);
376 q->stats.penaltydrop++;
377 goto drop;
378 }
379 goto enqueue;
380 }
381
382 r = get_random_u16() & SFB_MAX_PROB;
383
384 if (unlikely(r < p_min)) {
385 if (unlikely(p_min > SFB_MAX_PROB / 2)) {
386 /* If we're marking that many packets, then either
387 * this flow is unresponsive, or we're badly congested.
388 * In either case, we want to start dropping packets.
389 */
390 if (r < (p_min - SFB_MAX_PROB / 2) * 2) {
391 q->stats.earlydrop++;
392 goto drop;
393 }
394 }
395 if (INET_ECN_set_ce(skb)) {
396 q->stats.marked++;
397 } else {
398 q->stats.earlydrop++;
399 goto drop;
400 }
401 }
402
403 enqueue:
404 memcpy(&cb, sfb_skb_cb(skb), sizeof(cb));
405 ret = qdisc_enqueue(skb, child, to_free);
406 if (likely(ret == NET_XMIT_SUCCESS)) {
407 sch->qstats.backlog += len;
408 sch->q.qlen++;
409 increment_qlen(&cb, q);
410 } else if (net_xmit_drop_count(ret)) {
411 q->stats.childdrop++;
412 qdisc_qstats_drop(sch);
413 }
414 return ret;
415
416 drop:
417 qdisc_drop(skb, sch, to_free);
418 return NET_XMIT_CN;
419 other_drop:
420 if (ret & __NET_XMIT_BYPASS)
421 qdisc_qstats_drop(sch);
422 kfree_skb(skb);
423 return ret;
424 }
425
426 static struct sk_buff *sfb_dequeue(struct Qdisc *sch)
427 {
428 struct sfb_sched_data *q = qdisc_priv(sch);
429 struct Qdisc *child = q->qdisc;
430 struct sk_buff *skb;
431
432 skb = child->dequeue(q->qdisc);
433
434 if (skb) {
435 qdisc_bstats_update(sch, skb);
436 qdisc_qstats_backlog_dec(sch, skb);
437 sch->q.qlen--;
438 decrement_qlen(skb, q);
439 }
440
441 return skb;
442 }
443
444 static struct sk_buff *sfb_peek(struct Qdisc *sch)
445 {
446 struct sfb_sched_data *q = qdisc_priv(sch);
447 struct Qdisc *child = q->qdisc;
448
449 return child->ops->peek(child);
450 }
451
452 /* No sfb_drop -- impossible since the child doesn't return the dropped skb. */
453
454 static void sfb_reset(struct Qdisc *sch)
455 {
456 struct sfb_sched_data *q = qdisc_priv(sch);
457
458 if (likely(q->qdisc))
459 qdisc_reset(q->qdisc);
460 q->slot = 0;
461 q->double_buffering = false;
462 sfb_zero_all_buckets(q);
463 sfb_init_perturbation(0, q);
464 }
465
466 static void sfb_destroy(struct Qdisc *sch)
467 {
468 struct sfb_sched_data *q = qdisc_priv(sch);
469
470 tcf_block_put(q->block);
471 qdisc_put(q->qdisc);
472 }
473
474 static const struct nla_policy sfb_policy[TCA_SFB_MAX + 1] = {
475 [TCA_SFB_PARMS] = { .len = sizeof(struct tc_sfb_qopt) },
476 };
477
478 static const struct tc_sfb_qopt sfb_default_ops = {
479 .rehash_interval = 600 * MSEC_PER_SEC,
480 .warmup_time = 60 * MSEC_PER_SEC,
481 .limit = 0,
482 .max = 25,
483 .bin_size = 20,
484 .increment = (SFB_MAX_PROB + 500) / 1000, /* 0.1 % */
485 .decrement = (SFB_MAX_PROB + 3000) / 6000,
486 .penalty_rate = 10,
487 .penalty_burst = 20,
488 };
489
490 static int sfb_change(struct Qdisc *sch, struct nlattr *opt,
491 struct netlink_ext_ack *extack)
492 {
493 struct sfb_sched_data *q = qdisc_priv(sch);
494 struct Qdisc *child, *old;
495 struct nlattr *tb[TCA_SFB_MAX + 1];
496 const struct tc_sfb_qopt *ctl = &sfb_default_ops;
497 u32 limit;
498 int err;
499
500 if (opt) {
501 err = nla_parse_nested_deprecated(tb, TCA_SFB_MAX, opt,
502 sfb_policy, NULL);
503 if (err < 0)
504 return -EINVAL;
505
506 if (tb[TCA_SFB_PARMS] == NULL)
507 return -EINVAL;
508
509 ctl = nla_data(tb[TCA_SFB_PARMS]);
510 }
511
512 limit = ctl->limit;
513 if (limit == 0)
514 limit = qdisc_dev(sch)->tx_queue_len;
515
516 child = fifo_create_dflt(sch, &pfifo_qdisc_ops, limit, extack);
517 if (IS_ERR(child))
518 return PTR_ERR(child);
519
520 if (child != &noop_qdisc)
521 qdisc_hash_add(child, true);
522 sch_tree_lock(sch);
523
524 qdisc_purge_queue(q->qdisc);
525 old = q->qdisc;
526 q->qdisc = child;
527
528 q->rehash_interval = msecs_to_jiffies(ctl->rehash_interval);
529 q->warmup_time = msecs_to_jiffies(ctl->warmup_time);
530 q->rehash_time = jiffies;
531 q->limit = limit;
532 q->increment = ctl->increment;
533 q->decrement = ctl->decrement;
534 q->max = ctl->max;
535 q->bin_size = ctl->bin_size;
536 q->penalty_rate = ctl->penalty_rate;
537 q->penalty_burst = ctl->penalty_burst;
538 q->tokens_avail = ctl->penalty_burst;
539 q->token_time = jiffies;
540
541 q->slot = 0;
542 q->double_buffering = false;
543 sfb_zero_all_buckets(q);
544 sfb_init_perturbation(0, q);
545 sfb_init_perturbation(1, q);
546
547 sch_tree_unlock(sch);
548 qdisc_put(old);
549
550 return 0;
551 }
552
553 static int sfb_init(struct Qdisc *sch, struct nlattr *opt,
554 struct netlink_ext_ack *extack)
555 {
556 struct sfb_sched_data *q = qdisc_priv(sch);
557 int err;
558
559 err = tcf_block_get(&q->block, &q->filter_list, sch, extack);
560 if (err)
561 return err;
562
563 q->qdisc = &noop_qdisc;
564 return sfb_change(sch, opt, extack);
565 }
566
567 static int sfb_dump(struct Qdisc *sch, struct sk_buff *skb)
568 {
569 struct sfb_sched_data *q = qdisc_priv(sch);
570 struct nlattr *opts;
571 struct tc_sfb_qopt opt = {
572 .rehash_interval = jiffies_to_msecs(q->rehash_interval),
573 .warmup_time = jiffies_to_msecs(q->warmup_time),
574 .limit = q->limit,
575 .max = q->max,
576 .bin_size = q->bin_size,
577 .increment = q->increment,
578 .decrement = q->decrement,
579 .penalty_rate = q->penalty_rate,
580 .penalty_burst = q->penalty_burst,
581 };
582
583 sch->qstats.backlog = q->qdisc->qstats.backlog;
584 opts = nla_nest_start_noflag(skb, TCA_OPTIONS);
585 if (opts == NULL)
586 goto nla_put_failure;
587 if (nla_put(skb, TCA_SFB_PARMS, sizeof(opt), &opt))
588 goto nla_put_failure;
589 return nla_nest_end(skb, opts);
590
591 nla_put_failure:
592 nla_nest_cancel(skb, opts);
593 return -EMSGSIZE;
594 }
595
596 static int sfb_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
597 {
598 struct sfb_sched_data *q = qdisc_priv(sch);
599 struct tc_sfb_xstats st = {
600 .earlydrop = q->stats.earlydrop,
601 .penaltydrop = q->stats.penaltydrop,
602 .bucketdrop = q->stats.bucketdrop,
603 .queuedrop = q->stats.queuedrop,
604 .childdrop = q->stats.childdrop,
605 .marked = q->stats.marked,
606 };
607
608 st.maxqlen = sfb_compute_qlen(&st.maxprob, &st.avgprob, q);
609
610 return gnet_stats_copy_app(d, &st, sizeof(st));
611 }
612
613 static int sfb_dump_class(struct Qdisc *sch, unsigned long cl,
614 struct sk_buff *skb, struct tcmsg *tcm)
615 {
616 return -ENOSYS;
617 }
618
619 static int sfb_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
620 struct Qdisc **old, struct netlink_ext_ack *extack)
621 {
622 struct sfb_sched_data *q = qdisc_priv(sch);
623
624 if (new == NULL)
625 new = &noop_qdisc;
626
627 *old = qdisc_replace(sch, new, &q->qdisc);
628 return 0;
629 }
630
631 static struct Qdisc *sfb_leaf(struct Qdisc *sch, unsigned long arg)
632 {
633 struct sfb_sched_data *q = qdisc_priv(sch);
634
635 return q->qdisc;
636 }
637
638 static unsigned long sfb_find(struct Qdisc *sch, u32 classid)
639 {
640 return 1;
641 }
642
643 static void sfb_unbind(struct Qdisc *sch, unsigned long arg)
644 {
645 }
646
647 static int sfb_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
648 struct nlattr **tca, unsigned long *arg,
649 struct netlink_ext_ack *extack)
650 {
651 return -ENOSYS;
652 }
653
654 static int sfb_delete(struct Qdisc *sch, unsigned long cl,
655 struct netlink_ext_ack *extack)
656 {
657 return -ENOSYS;
658 }
659
660 static void sfb_walk(struct Qdisc *sch, struct qdisc_walker *walker)
661 {
662 if (!walker->stop) {
663 tc_qdisc_stats_dump(sch, 1, walker);
664 }
665 }
666
667 static struct tcf_block *sfb_tcf_block(struct Qdisc *sch, unsigned long cl,
668 struct netlink_ext_ack *extack)
669 {
670 struct sfb_sched_data *q = qdisc_priv(sch);
671
672 if (cl)
673 return NULL;
674 return q->block;
675 }
676
677 static unsigned long sfb_bind(struct Qdisc *sch, unsigned long parent,
678 u32 classid)
679 {
680 return 0;
681 }
682
683
684 static const struct Qdisc_class_ops sfb_class_ops = {
685 .graft = sfb_graft,
686 .leaf = sfb_leaf,
687 .find = sfb_find,
688 .change = sfb_change_class,
689 .delete = sfb_delete,
690 .walk = sfb_walk,
691 .tcf_block = sfb_tcf_block,
692 .bind_tcf = sfb_bind,
693 .unbind_tcf = sfb_unbind,
694 .dump = sfb_dump_class,
695 };
696
697 static struct Qdisc_ops sfb_qdisc_ops __read_mostly = {
698 .id = "sfb",
699 .priv_size = sizeof(struct sfb_sched_data),
700 .cl_ops = &sfb_class_ops,
701 .enqueue = sfb_enqueue,
702 .dequeue = sfb_dequeue,
703 .peek = sfb_peek,
704 .init = sfb_init,
705 .reset = sfb_reset,
706 .destroy = sfb_destroy,
707 .change = sfb_change,
708 .dump = sfb_dump,
709 .dump_stats = sfb_dump_stats,
710 .owner = THIS_MODULE,
711 };
712 MODULE_ALIAS_NET_SCH("sfb");
713
714 static int __init sfb_module_init(void)
715 {
716 return register_qdisc(&sfb_qdisc_ops);
717 }
718
719 static void __exit sfb_module_exit(void)
720 {
721 unregister_qdisc(&sfb_qdisc_ops);
722 }
723
724 module_init(sfb_module_init)
725 module_exit(sfb_module_exit)
726
727 MODULE_DESCRIPTION("Stochastic Fair Blue queue discipline");
728 MODULE_AUTHOR("Juliusz Chroboczek");
729 MODULE_AUTHOR("Eric Dumazet");
730 MODULE_LICENSE("GPL");
731
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