sch_sfb.c

  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" */
 39struct 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 */
 47struct sfb_bins {
 48	siphash_key_t	  perturbation; /* siphash key */
 49	struct sfb_bucket bins[SFB_LEVELS][SFB_NUMBUCKETS];
 50};
 51
 52struct 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 */
 88struct sfb_skb_cb {
 89	u32 hashes[2];
 90};
 91
 92static 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 */
102static 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 */
111static 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
118static u32 prob_minus(u32 p1, u32 p2)
119{
120	return p1 > p2 ? p1 - p2 : 0;
121}
122
123static 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
138static 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
151static 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
167static 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
180static 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
185static 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
190static 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 */
198static 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
218static 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
224static 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 */
234static 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
254static 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
279static int sfb_enqueue(struct sk_buff *skb, struct Qdisc *sch,
280		       struct sk_buff **to_free)
281{
282
283	enum skb_drop_reason reason = SKB_DROP_REASON_QDISC_OVERLIMIT;
284	struct sfb_sched_data *q = qdisc_priv(sch);
285	unsigned int len = qdisc_pkt_len(skb);
286	struct Qdisc *child = q->qdisc;
287	struct tcf_proto *fl;
288	struct sfb_skb_cb cb;
289	int i;
290	u32 p_min = ~0;
291	u32 minqlen = ~0;
292	u32 r, sfbhash;
293	u32 slot = q->slot;
294	int ret = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
295
296	if (unlikely(sch->q.qlen >= q->limit)) {
297		qdisc_qstats_overlimit(sch);
298		q->stats.queuedrop++;
299		goto drop;
300	}
301
302	if (q->rehash_interval > 0) {
303		unsigned long limit = q->rehash_time + q->rehash_interval;
304
305		if (unlikely(time_after(jiffies, limit))) {
306			sfb_swap_slot(q);
307			q->rehash_time = jiffies;
308		} else if (unlikely(!q->double_buffering && q->warmup_time > 0 &&
309				    time_after(jiffies, limit - q->warmup_time))) {
310			q->double_buffering = true;
311		}
312	}
313
314	fl = rcu_dereference_bh(q->filter_list);
315	if (fl) {
316		u32 salt;
317
318		/* If using external classifiers, get result and record it. */
319		if (!sfb_classify(skb, fl, &ret, &salt))
320			goto other_drop;
321		sfbhash = siphash_1u32(salt, &q->bins[slot].perturbation);
322	} else {
323		sfbhash = skb_get_hash_perturb(skb, &q->bins[slot].perturbation);
324	}
325
326
327	if (!sfbhash)
328		sfbhash = 1;
329	sfb_skb_cb(skb)->hashes[slot] = sfbhash;
330
331	for (i = 0; i < SFB_LEVELS; i++) {
332		u32 hash = sfbhash & SFB_BUCKET_MASK;
333		struct sfb_bucket *b = &q->bins[slot].bins[i][hash];
334
335		sfbhash >>= SFB_BUCKET_SHIFT;
336		if (b->qlen == 0)
337			decrement_prob(b, q);
338		else if (b->qlen >= q->bin_size)
339			increment_prob(b, q);
340		if (minqlen > b->qlen)
341			minqlen = b->qlen;
342		if (p_min > b->p_mark)
343			p_min = b->p_mark;
344	}
345
346	slot ^= 1;
347	sfb_skb_cb(skb)->hashes[slot] = 0;
348
349	if (unlikely(minqlen >= q->max)) {
350		qdisc_qstats_overlimit(sch);
351		q->stats.bucketdrop++;
352		goto drop;
353	}
354
355	if (unlikely(p_min >= SFB_MAX_PROB)) {
356		/* Inelastic flow */
357		if (q->double_buffering) {
358			sfbhash = skb_get_hash_perturb(skb,
359			    &q->bins[slot].perturbation);
360			if (!sfbhash)
361				sfbhash = 1;
362			sfb_skb_cb(skb)->hashes[slot] = sfbhash;
363
364			for (i = 0; i < SFB_LEVELS; i++) {
365				u32 hash = sfbhash & SFB_BUCKET_MASK;
366				struct sfb_bucket *b = &q->bins[slot].bins[i][hash];
367
368				sfbhash >>= SFB_BUCKET_SHIFT;
369				if (b->qlen == 0)
370					decrement_prob(b, q);
371				else if (b->qlen >= q->bin_size)
372					increment_prob(b, q);
373			}
374		}
375		if (sfb_rate_limit(skb, q)) {
376			qdisc_qstats_overlimit(sch);
377			q->stats.penaltydrop++;
378			goto drop;
379		}
380		goto enqueue;
381	}
382
383	r = get_random_u16() & SFB_MAX_PROB;
384	reason = SKB_DROP_REASON_QDISC_CONGESTED;
385
386	if (unlikely(r < p_min)) {
387		if (unlikely(p_min > SFB_MAX_PROB / 2)) {
388			/* If we're marking that many packets, then either
389			 * this flow is unresponsive, or we're badly congested.
390			 * In either case, we want to start dropping packets.
391			 */
392			if (r < (p_min - SFB_MAX_PROB / 2) * 2) {
393				q->stats.earlydrop++;
394				goto drop;
395			}
396		}
397		if (INET_ECN_set_ce(skb)) {
398			q->stats.marked++;
399		} else {
400			q->stats.earlydrop++;
401			goto drop;
402		}
403	}
404
405enqueue:
406	memcpy(&cb, sfb_skb_cb(skb), sizeof(cb));
407	ret = qdisc_enqueue(skb, child, to_free);
408	if (likely(ret == NET_XMIT_SUCCESS)) {
409		sch->qstats.backlog += len;
410		sch->q.qlen++;
411		increment_qlen(&cb, q);
412	} else if (net_xmit_drop_count(ret)) {
413		q->stats.childdrop++;
414		qdisc_qstats_drop(sch);
415	}
416	return ret;
417
418drop:
419	qdisc_drop_reason(skb, sch, to_free, reason);
420	return NET_XMIT_CN;
421other_drop:
422	if (ret & __NET_XMIT_BYPASS)
423		qdisc_qstats_drop(sch);
424	kfree_skb(skb);
425	return ret;
426}
427
428static struct sk_buff *sfb_dequeue(struct Qdisc *sch)
429{
430	struct sfb_sched_data *q = qdisc_priv(sch);
431	struct Qdisc *child = q->qdisc;
432	struct sk_buff *skb;
433
434	skb = child->dequeue(q->qdisc);
435
436	if (skb) {
437		qdisc_bstats_update(sch, skb);
438		qdisc_qstats_backlog_dec(sch, skb);
439		sch->q.qlen--;
440		decrement_qlen(skb, q);
441	}
442
443	return skb;
444}
445
446static struct sk_buff *sfb_peek(struct Qdisc *sch)
447{
448	struct sfb_sched_data *q = qdisc_priv(sch);
449	struct Qdisc *child = q->qdisc;
450
451	return child->ops->peek(child);
452}
453
454/* No sfb_drop -- impossible since the child doesn't return the dropped skb. */
455
456static void sfb_reset(struct Qdisc *sch)
457{
458	struct sfb_sched_data *q = qdisc_priv(sch);
459
460	if (likely(q->qdisc))
461		qdisc_reset(q->qdisc);
462	q->slot = 0;
463	q->double_buffering = false;
464	sfb_zero_all_buckets(q);
465	sfb_init_perturbation(0, q);
466}
467
468static void sfb_destroy(struct Qdisc *sch)
469{
470	struct sfb_sched_data *q = qdisc_priv(sch);
471
472	tcf_block_put(q->block);
473	qdisc_put(q->qdisc);
474}
475
476static const struct nla_policy sfb_policy[TCA_SFB_MAX + 1] = {
477	[TCA_SFB_PARMS]	= { .len = sizeof(struct tc_sfb_qopt) },
478};
479
480static const struct tc_sfb_qopt sfb_default_ops = {
481	.rehash_interval = 600 * MSEC_PER_SEC,
482	.warmup_time = 60 * MSEC_PER_SEC,
483	.limit = 0,
484	.max = 25,
485	.bin_size = 20,
486	.increment = (SFB_MAX_PROB + 500) / 1000, /* 0.1 % */
487	.decrement = (SFB_MAX_PROB + 3000) / 6000,
488	.penalty_rate = 10,
489	.penalty_burst = 20,
490};
491
492static int sfb_change(struct Qdisc *sch, struct nlattr *opt,
493		      struct netlink_ext_ack *extack)
494{
495	struct sfb_sched_data *q = qdisc_priv(sch);
496	struct Qdisc *child, *old;
497	struct nlattr *tb[TCA_SFB_MAX + 1];
498	const struct tc_sfb_qopt *ctl = &sfb_default_ops;
499	u32 limit;
500	int err;
501
502	if (opt) {
503		err = nla_parse_nested_deprecated(tb, TCA_SFB_MAX, opt,
504						  sfb_policy, NULL);
505		if (err < 0)
506			return -EINVAL;
507
508		if (tb[TCA_SFB_PARMS] == NULL)
509			return -EINVAL;
510
511		ctl = nla_data(tb[TCA_SFB_PARMS]);
512	}
513
514	limit = ctl->limit;
515	if (limit == 0)
516		limit = qdisc_dev(sch)->tx_queue_len;
517
518	child = fifo_create_dflt(sch, &pfifo_qdisc_ops, limit, extack);
519	if (IS_ERR(child))
520		return PTR_ERR(child);
521
522	if (child != &noop_qdisc)
523		qdisc_hash_add(child, true);
524	sch_tree_lock(sch);
525
526	qdisc_purge_queue(q->qdisc);
527	old = q->qdisc;
528	q->qdisc = child;
529
530	q->rehash_interval = msecs_to_jiffies(ctl->rehash_interval);
531	q->warmup_time = msecs_to_jiffies(ctl->warmup_time);
532	q->rehash_time = jiffies;
533	q->limit = limit;
534	q->increment = ctl->increment;
535	q->decrement = ctl->decrement;
536	q->max = ctl->max;
537	q->bin_size = ctl->bin_size;
538	q->penalty_rate = ctl->penalty_rate;
539	q->penalty_burst = ctl->penalty_burst;
540	q->tokens_avail = ctl->penalty_burst;
541	q->token_time = jiffies;
542
543	q->slot = 0;
544	q->double_buffering = false;
545	sfb_zero_all_buckets(q);
546	sfb_init_perturbation(0, q);
547	sfb_init_perturbation(1, q);
548
549	sch_tree_unlock(sch);
550	qdisc_put(old);
551
552	return 0;
553}
554
555static int sfb_init(struct Qdisc *sch, struct nlattr *opt,
556		    struct netlink_ext_ack *extack)
557{
558	struct sfb_sched_data *q = qdisc_priv(sch);
559	int err;
560
561	err = tcf_block_get(&q->block, &q->filter_list, sch, extack);
562	if (err)
563		return err;
564
565	q->qdisc = &noop_qdisc;
566	return sfb_change(sch, opt, extack);
567}
568
569static int sfb_dump(struct Qdisc *sch, struct sk_buff *skb)
570{
571	struct sfb_sched_data *q = qdisc_priv(sch);
572	struct nlattr *opts;
573	struct tc_sfb_qopt opt = {
574		.rehash_interval = jiffies_to_msecs(q->rehash_interval),
575		.warmup_time = jiffies_to_msecs(q->warmup_time),
576		.limit = q->limit,
577		.max = q->max,
578		.bin_size = q->bin_size,
579		.increment = q->increment,
580		.decrement = q->decrement,
581		.penalty_rate = q->penalty_rate,
582		.penalty_burst = q->penalty_burst,
583	};
584
585	sch->qstats.backlog = q->qdisc->qstats.backlog;
586	opts = nla_nest_start_noflag(skb, TCA_OPTIONS);
587	if (opts == NULL)
588		goto nla_put_failure;
589	if (nla_put(skb, TCA_SFB_PARMS, sizeof(opt), &opt))
590		goto nla_put_failure;
591	return nla_nest_end(skb, opts);
592
593nla_put_failure:
594	nla_nest_cancel(skb, opts);
595	return -EMSGSIZE;
596}
597
598static int sfb_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
599{
600	struct sfb_sched_data *q = qdisc_priv(sch);
601	struct tc_sfb_xstats st = {
602		.earlydrop = q->stats.earlydrop,
603		.penaltydrop = q->stats.penaltydrop,
604		.bucketdrop = q->stats.bucketdrop,
605		.queuedrop = q->stats.queuedrop,
606		.childdrop = q->stats.childdrop,
607		.marked = q->stats.marked,
608	};
609
610	st.maxqlen = sfb_compute_qlen(&st.maxprob, &st.avgprob, q);
611
612	return gnet_stats_copy_app(d, &st, sizeof(st));
613}
614
615static int sfb_dump_class(struct Qdisc *sch, unsigned long cl,
616			  struct sk_buff *skb, struct tcmsg *tcm)
617{
618	return -ENOSYS;
619}
620
621static int sfb_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
622		     struct Qdisc **old, struct netlink_ext_ack *extack)
623{
624	struct sfb_sched_data *q = qdisc_priv(sch);
625
626	if (new == NULL)
627		new = &noop_qdisc;
628
629	*old = qdisc_replace(sch, new, &q->qdisc);
630	return 0;
631}
632
633static struct Qdisc *sfb_leaf(struct Qdisc *sch, unsigned long arg)
634{
635	struct sfb_sched_data *q = qdisc_priv(sch);
636
637	return q->qdisc;
638}
639
640static unsigned long sfb_find(struct Qdisc *sch, u32 classid)
641{
642	return 1;
643}
644
645static void sfb_unbind(struct Qdisc *sch, unsigned long arg)
646{
647}
648
649static int sfb_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
650			    struct nlattr **tca, unsigned long *arg,
651			    struct netlink_ext_ack *extack)
652{
653	return -ENOSYS;
654}
655
656static int sfb_delete(struct Qdisc *sch, unsigned long cl,
657		      struct netlink_ext_ack *extack)
658{
659	return -ENOSYS;
660}
661
662static void sfb_walk(struct Qdisc *sch, struct qdisc_walker *walker)
663{
664	if (!walker->stop) {
665		tc_qdisc_stats_dump(sch, 1, walker);
666	}
667}
668
669static struct tcf_block *sfb_tcf_block(struct Qdisc *sch, unsigned long cl,
670				       struct netlink_ext_ack *extack)
671{
672	struct sfb_sched_data *q = qdisc_priv(sch);
673
674	if (cl)
675		return NULL;
676	return q->block;
677}
678
679static unsigned long sfb_bind(struct Qdisc *sch, unsigned long parent,
680			      u32 classid)
681{
682	return 0;
683}
684
685
686static const struct Qdisc_class_ops sfb_class_ops = {
687	.graft		=	sfb_graft,
688	.leaf		=	sfb_leaf,
689	.find		=	sfb_find,
690	.change		=	sfb_change_class,
691	.delete		=	sfb_delete,
692	.walk		=	sfb_walk,
693	.tcf_block	=	sfb_tcf_block,
694	.bind_tcf	=	sfb_bind,
695	.unbind_tcf	=	sfb_unbind,
696	.dump		=	sfb_dump_class,
697};
698
699static struct Qdisc_ops sfb_qdisc_ops __read_mostly = {
700	.id		=	"sfb",
701	.priv_size	=	sizeof(struct sfb_sched_data),
702	.cl_ops		=	&sfb_class_ops,
703	.enqueue	=	sfb_enqueue,
704	.dequeue	=	sfb_dequeue,
705	.peek		=	sfb_peek,
706	.init		=	sfb_init,
707	.reset		=	sfb_reset,
708	.destroy	=	sfb_destroy,
709	.change		=	sfb_change,
710	.dump		=	sfb_dump,
711	.dump_stats	=	sfb_dump_stats,
712	.owner		=	THIS_MODULE,
713};
714MODULE_ALIAS_NET_SCH("sfb");
715
716static int __init sfb_module_init(void)
717{
718	return register_qdisc(&sfb_qdisc_ops);
719}
720
721static void __exit sfb_module_exit(void)
722{
723	unregister_qdisc(&sfb_qdisc_ops);
724}
725
726module_init(sfb_module_init)
727module_exit(sfb_module_exit)
728
729MODULE_DESCRIPTION("Stochastic Fair Blue queue discipline");
730MODULE_AUTHOR("Juliusz Chroboczek");
731MODULE_AUTHOR("Eric Dumazet");
732MODULE_LICENSE("GPL");