xref: /openbmc/linux/net/sched/sch_api.c (revision d003d772)
1 /*
2  * net/sched/sch_api.c	Packet scheduler API.
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  *
11  * Fixes:
12  *
13  * Rani Assaf <rani@magic.metawire.com> :980802: JIFFIES and CPU clock sources are repaired.
14  * Eduardo J. Blanco <ejbs@netlabs.com.uy> :990222: kmod support
15  * Jamal Hadi Salim <hadi@nortelnetworks.com>: 990601: ingress support
16  */
17 
18 #include <linux/module.h>
19 #include <linux/types.h>
20 #include <linux/kernel.h>
21 #include <linux/string.h>
22 #include <linux/errno.h>
23 #include <linux/skbuff.h>
24 #include <linux/init.h>
25 #include <linux/proc_fs.h>
26 #include <linux/seq_file.h>
27 #include <linux/kmod.h>
28 #include <linux/list.h>
29 #include <linux/hrtimer.h>
30 #include <linux/slab.h>
31 #include <linux/hashtable.h>
32 
33 #include <net/net_namespace.h>
34 #include <net/sock.h>
35 #include <net/netlink.h>
36 #include <net/pkt_sched.h>
37 #include <net/pkt_cls.h>
38 
39 /*
40 
41    Short review.
42    -------------
43 
44    This file consists of two interrelated parts:
45 
46    1. queueing disciplines manager frontend.
47    2. traffic classes manager frontend.
48 
49    Generally, queueing discipline ("qdisc") is a black box,
50    which is able to enqueue packets and to dequeue them (when
51    device is ready to send something) in order and at times
52    determined by algorithm hidden in it.
53 
54    qdisc's are divided to two categories:
55    - "queues", which have no internal structure visible from outside.
56    - "schedulers", which split all the packets to "traffic classes",
57      using "packet classifiers" (look at cls_api.c)
58 
59    In turn, classes may have child qdiscs (as rule, queues)
60    attached to them etc. etc. etc.
61 
62    The goal of the routines in this file is to translate
63    information supplied by user in the form of handles
64    to more intelligible for kernel form, to make some sanity
65    checks and part of work, which is common to all qdiscs
66    and to provide rtnetlink notifications.
67 
68    All real intelligent work is done inside qdisc modules.
69 
70 
71 
72    Every discipline has two major routines: enqueue and dequeue.
73 
74    ---dequeue
75 
76    dequeue usually returns a skb to send. It is allowed to return NULL,
77    but it does not mean that queue is empty, it just means that
78    discipline does not want to send anything this time.
79    Queue is really empty if q->q.qlen == 0.
80    For complicated disciplines with multiple queues q->q is not
81    real packet queue, but however q->q.qlen must be valid.
82 
83    ---enqueue
84 
85    enqueue returns 0, if packet was enqueued successfully.
86    If packet (this one or another one) was dropped, it returns
87    not zero error code.
88    NET_XMIT_DROP 	- this packet dropped
89      Expected action: do not backoff, but wait until queue will clear.
90    NET_XMIT_CN	 	- probably this packet enqueued, but another one dropped.
91      Expected action: backoff or ignore
92 
93    Auxiliary routines:
94 
95    ---peek
96 
97    like dequeue but without removing a packet from the queue
98 
99    ---reset
100 
101    returns qdisc to initial state: purge all buffers, clear all
102    timers, counters (except for statistics) etc.
103 
104    ---init
105 
106    initializes newly created qdisc.
107 
108    ---destroy
109 
110    destroys resources allocated by init and during lifetime of qdisc.
111 
112    ---change
113 
114    changes qdisc parameters.
115  */
116 
117 /* Protects list of registered TC modules. It is pure SMP lock. */
118 static DEFINE_RWLOCK(qdisc_mod_lock);
119 
120 
121 /************************************************
122  *	Queueing disciplines manipulation.	*
123  ************************************************/
124 
125 
126 /* The list of all installed queueing disciplines. */
127 
128 static struct Qdisc_ops *qdisc_base;
129 
130 /* Register/unregister queueing discipline */
131 
132 int register_qdisc(struct Qdisc_ops *qops)
133 {
134 	struct Qdisc_ops *q, **qp;
135 	int rc = -EEXIST;
136 
137 	write_lock(&qdisc_mod_lock);
138 	for (qp = &qdisc_base; (q = *qp) != NULL; qp = &q->next)
139 		if (!strcmp(qops->id, q->id))
140 			goto out;
141 
142 	if (qops->enqueue == NULL)
143 		qops->enqueue = noop_qdisc_ops.enqueue;
144 	if (qops->peek == NULL) {
145 		if (qops->dequeue == NULL)
146 			qops->peek = noop_qdisc_ops.peek;
147 		else
148 			goto out_einval;
149 	}
150 	if (qops->dequeue == NULL)
151 		qops->dequeue = noop_qdisc_ops.dequeue;
152 
153 	if (qops->cl_ops) {
154 		const struct Qdisc_class_ops *cops = qops->cl_ops;
155 
156 		if (!(cops->find && cops->walk && cops->leaf))
157 			goto out_einval;
158 
159 		if (cops->tcf_block && !(cops->bind_tcf && cops->unbind_tcf))
160 			goto out_einval;
161 	}
162 
163 	qops->next = NULL;
164 	*qp = qops;
165 	rc = 0;
166 out:
167 	write_unlock(&qdisc_mod_lock);
168 	return rc;
169 
170 out_einval:
171 	rc = -EINVAL;
172 	goto out;
173 }
174 EXPORT_SYMBOL(register_qdisc);
175 
176 int unregister_qdisc(struct Qdisc_ops *qops)
177 {
178 	struct Qdisc_ops *q, **qp;
179 	int err = -ENOENT;
180 
181 	write_lock(&qdisc_mod_lock);
182 	for (qp = &qdisc_base; (q = *qp) != NULL; qp = &q->next)
183 		if (q == qops)
184 			break;
185 	if (q) {
186 		*qp = q->next;
187 		q->next = NULL;
188 		err = 0;
189 	}
190 	write_unlock(&qdisc_mod_lock);
191 	return err;
192 }
193 EXPORT_SYMBOL(unregister_qdisc);
194 
195 /* Get default qdisc if not otherwise specified */
196 void qdisc_get_default(char *name, size_t len)
197 {
198 	read_lock(&qdisc_mod_lock);
199 	strlcpy(name, default_qdisc_ops->id, len);
200 	read_unlock(&qdisc_mod_lock);
201 }
202 
203 static struct Qdisc_ops *qdisc_lookup_default(const char *name)
204 {
205 	struct Qdisc_ops *q = NULL;
206 
207 	for (q = qdisc_base; q; q = q->next) {
208 		if (!strcmp(name, q->id)) {
209 			if (!try_module_get(q->owner))
210 				q = NULL;
211 			break;
212 		}
213 	}
214 
215 	return q;
216 }
217 
218 /* Set new default qdisc to use */
219 int qdisc_set_default(const char *name)
220 {
221 	const struct Qdisc_ops *ops;
222 
223 	if (!capable(CAP_NET_ADMIN))
224 		return -EPERM;
225 
226 	write_lock(&qdisc_mod_lock);
227 	ops = qdisc_lookup_default(name);
228 	if (!ops) {
229 		/* Not found, drop lock and try to load module */
230 		write_unlock(&qdisc_mod_lock);
231 		request_module("sch_%s", name);
232 		write_lock(&qdisc_mod_lock);
233 
234 		ops = qdisc_lookup_default(name);
235 	}
236 
237 	if (ops) {
238 		/* Set new default */
239 		module_put(default_qdisc_ops->owner);
240 		default_qdisc_ops = ops;
241 	}
242 	write_unlock(&qdisc_mod_lock);
243 
244 	return ops ? 0 : -ENOENT;
245 }
246 
247 #ifdef CONFIG_NET_SCH_DEFAULT
248 /* Set default value from kernel config */
249 static int __init sch_default_qdisc(void)
250 {
251 	return qdisc_set_default(CONFIG_DEFAULT_NET_SCH);
252 }
253 late_initcall(sch_default_qdisc);
254 #endif
255 
256 /* We know handle. Find qdisc among all qdisc's attached to device
257  * (root qdisc, all its children, children of children etc.)
258  * Note: caller either uses rtnl or rcu_read_lock()
259  */
260 
261 static struct Qdisc *qdisc_match_from_root(struct Qdisc *root, u32 handle)
262 {
263 	struct Qdisc *q;
264 
265 	if (!qdisc_dev(root))
266 		return (root->handle == handle ? root : NULL);
267 
268 	if (!(root->flags & TCQ_F_BUILTIN) &&
269 	    root->handle == handle)
270 		return root;
271 
272 	hash_for_each_possible_rcu(qdisc_dev(root)->qdisc_hash, q, hash, handle) {
273 		if (q->handle == handle)
274 			return q;
275 	}
276 	return NULL;
277 }
278 
279 void qdisc_hash_add(struct Qdisc *q, bool invisible)
280 {
281 	if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS)) {
282 		ASSERT_RTNL();
283 		hash_add_rcu(qdisc_dev(q)->qdisc_hash, &q->hash, q->handle);
284 		if (invisible)
285 			q->flags |= TCQ_F_INVISIBLE;
286 	}
287 }
288 EXPORT_SYMBOL(qdisc_hash_add);
289 
290 void qdisc_hash_del(struct Qdisc *q)
291 {
292 	if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS)) {
293 		ASSERT_RTNL();
294 		hash_del_rcu(&q->hash);
295 	}
296 }
297 EXPORT_SYMBOL(qdisc_hash_del);
298 
299 struct Qdisc *qdisc_lookup(struct net_device *dev, u32 handle)
300 {
301 	struct Qdisc *q;
302 
303 	if (!handle)
304 		return NULL;
305 	q = qdisc_match_from_root(dev->qdisc, handle);
306 	if (q)
307 		goto out;
308 
309 	if (dev_ingress_queue(dev))
310 		q = qdisc_match_from_root(
311 			dev_ingress_queue(dev)->qdisc_sleeping,
312 			handle);
313 out:
314 	return q;
315 }
316 
317 struct Qdisc *qdisc_lookup_rcu(struct net_device *dev, u32 handle)
318 {
319 	struct netdev_queue *nq;
320 	struct Qdisc *q;
321 
322 	if (!handle)
323 		return NULL;
324 	q = qdisc_match_from_root(dev->qdisc, handle);
325 	if (q)
326 		goto out;
327 
328 	nq = dev_ingress_queue_rcu(dev);
329 	if (nq)
330 		q = qdisc_match_from_root(nq->qdisc_sleeping, handle);
331 out:
332 	return q;
333 }
334 
335 static struct Qdisc *qdisc_leaf(struct Qdisc *p, u32 classid)
336 {
337 	unsigned long cl;
338 	const struct Qdisc_class_ops *cops = p->ops->cl_ops;
339 
340 	if (cops == NULL)
341 		return NULL;
342 	cl = cops->find(p, classid);
343 
344 	if (cl == 0)
345 		return NULL;
346 	return cops->leaf(p, cl);
347 }
348 
349 /* Find queueing discipline by name */
350 
351 static struct Qdisc_ops *qdisc_lookup_ops(struct nlattr *kind)
352 {
353 	struct Qdisc_ops *q = NULL;
354 
355 	if (kind) {
356 		read_lock(&qdisc_mod_lock);
357 		for (q = qdisc_base; q; q = q->next) {
358 			if (nla_strcmp(kind, q->id) == 0) {
359 				if (!try_module_get(q->owner))
360 					q = NULL;
361 				break;
362 			}
363 		}
364 		read_unlock(&qdisc_mod_lock);
365 	}
366 	return q;
367 }
368 
369 /* The linklayer setting were not transferred from iproute2, in older
370  * versions, and the rate tables lookup systems have been dropped in
371  * the kernel. To keep backward compatible with older iproute2 tc
372  * utils, we detect the linklayer setting by detecting if the rate
373  * table were modified.
374  *
375  * For linklayer ATM table entries, the rate table will be aligned to
376  * 48 bytes, thus some table entries will contain the same value.  The
377  * mpu (min packet unit) is also encoded into the old rate table, thus
378  * starting from the mpu, we find low and high table entries for
379  * mapping this cell.  If these entries contain the same value, when
380  * the rate tables have been modified for linklayer ATM.
381  *
382  * This is done by rounding mpu to the nearest 48 bytes cell/entry,
383  * and then roundup to the next cell, calc the table entry one below,
384  * and compare.
385  */
386 static __u8 __detect_linklayer(struct tc_ratespec *r, __u32 *rtab)
387 {
388 	int low       = roundup(r->mpu, 48);
389 	int high      = roundup(low+1, 48);
390 	int cell_low  = low >> r->cell_log;
391 	int cell_high = (high >> r->cell_log) - 1;
392 
393 	/* rtab is too inaccurate at rates > 100Mbit/s */
394 	if ((r->rate > (100000000/8)) || (rtab[0] == 0)) {
395 		pr_debug("TC linklayer: Giving up ATM detection\n");
396 		return TC_LINKLAYER_ETHERNET;
397 	}
398 
399 	if ((cell_high > cell_low) && (cell_high < 256)
400 	    && (rtab[cell_low] == rtab[cell_high])) {
401 		pr_debug("TC linklayer: Detected ATM, low(%d)=high(%d)=%u\n",
402 			 cell_low, cell_high, rtab[cell_high]);
403 		return TC_LINKLAYER_ATM;
404 	}
405 	return TC_LINKLAYER_ETHERNET;
406 }
407 
408 static struct qdisc_rate_table *qdisc_rtab_list;
409 
410 struct qdisc_rate_table *qdisc_get_rtab(struct tc_ratespec *r,
411 					struct nlattr *tab,
412 					struct netlink_ext_ack *extack)
413 {
414 	struct qdisc_rate_table *rtab;
415 
416 	if (tab == NULL || r->rate == 0 || r->cell_log == 0 ||
417 	    nla_len(tab) != TC_RTAB_SIZE) {
418 		NL_SET_ERR_MSG(extack, "Invalid rate table parameters for searching");
419 		return NULL;
420 	}
421 
422 	for (rtab = qdisc_rtab_list; rtab; rtab = rtab->next) {
423 		if (!memcmp(&rtab->rate, r, sizeof(struct tc_ratespec)) &&
424 		    !memcmp(&rtab->data, nla_data(tab), 1024)) {
425 			rtab->refcnt++;
426 			return rtab;
427 		}
428 	}
429 
430 	rtab = kmalloc(sizeof(*rtab), GFP_KERNEL);
431 	if (rtab) {
432 		rtab->rate = *r;
433 		rtab->refcnt = 1;
434 		memcpy(rtab->data, nla_data(tab), 1024);
435 		if (r->linklayer == TC_LINKLAYER_UNAWARE)
436 			r->linklayer = __detect_linklayer(r, rtab->data);
437 		rtab->next = qdisc_rtab_list;
438 		qdisc_rtab_list = rtab;
439 	} else {
440 		NL_SET_ERR_MSG(extack, "Failed to allocate new qdisc rate table");
441 	}
442 	return rtab;
443 }
444 EXPORT_SYMBOL(qdisc_get_rtab);
445 
446 void qdisc_put_rtab(struct qdisc_rate_table *tab)
447 {
448 	struct qdisc_rate_table *rtab, **rtabp;
449 
450 	if (!tab || --tab->refcnt)
451 		return;
452 
453 	for (rtabp = &qdisc_rtab_list;
454 	     (rtab = *rtabp) != NULL;
455 	     rtabp = &rtab->next) {
456 		if (rtab == tab) {
457 			*rtabp = rtab->next;
458 			kfree(rtab);
459 			return;
460 		}
461 	}
462 }
463 EXPORT_SYMBOL(qdisc_put_rtab);
464 
465 static LIST_HEAD(qdisc_stab_list);
466 
467 static const struct nla_policy stab_policy[TCA_STAB_MAX + 1] = {
468 	[TCA_STAB_BASE]	= { .len = sizeof(struct tc_sizespec) },
469 	[TCA_STAB_DATA] = { .type = NLA_BINARY },
470 };
471 
472 static struct qdisc_size_table *qdisc_get_stab(struct nlattr *opt,
473 					       struct netlink_ext_ack *extack)
474 {
475 	struct nlattr *tb[TCA_STAB_MAX + 1];
476 	struct qdisc_size_table *stab;
477 	struct tc_sizespec *s;
478 	unsigned int tsize = 0;
479 	u16 *tab = NULL;
480 	int err;
481 
482 	err = nla_parse_nested(tb, TCA_STAB_MAX, opt, stab_policy, extack);
483 	if (err < 0)
484 		return ERR_PTR(err);
485 	if (!tb[TCA_STAB_BASE]) {
486 		NL_SET_ERR_MSG(extack, "Size table base attribute is missing");
487 		return ERR_PTR(-EINVAL);
488 	}
489 
490 	s = nla_data(tb[TCA_STAB_BASE]);
491 
492 	if (s->tsize > 0) {
493 		if (!tb[TCA_STAB_DATA]) {
494 			NL_SET_ERR_MSG(extack, "Size table data attribute is missing");
495 			return ERR_PTR(-EINVAL);
496 		}
497 		tab = nla_data(tb[TCA_STAB_DATA]);
498 		tsize = nla_len(tb[TCA_STAB_DATA]) / sizeof(u16);
499 	}
500 
501 	if (tsize != s->tsize || (!tab && tsize > 0)) {
502 		NL_SET_ERR_MSG(extack, "Invalid size of size table");
503 		return ERR_PTR(-EINVAL);
504 	}
505 
506 	list_for_each_entry(stab, &qdisc_stab_list, list) {
507 		if (memcmp(&stab->szopts, s, sizeof(*s)))
508 			continue;
509 		if (tsize > 0 && memcmp(stab->data, tab, tsize * sizeof(u16)))
510 			continue;
511 		stab->refcnt++;
512 		return stab;
513 	}
514 
515 	stab = kmalloc(sizeof(*stab) + tsize * sizeof(u16), GFP_KERNEL);
516 	if (!stab)
517 		return ERR_PTR(-ENOMEM);
518 
519 	stab->refcnt = 1;
520 	stab->szopts = *s;
521 	if (tsize > 0)
522 		memcpy(stab->data, tab, tsize * sizeof(u16));
523 
524 	list_add_tail(&stab->list, &qdisc_stab_list);
525 
526 	return stab;
527 }
528 
529 void qdisc_put_stab(struct qdisc_size_table *tab)
530 {
531 	if (!tab)
532 		return;
533 
534 	if (--tab->refcnt == 0) {
535 		list_del(&tab->list);
536 		kfree_rcu(tab, rcu);
537 	}
538 }
539 EXPORT_SYMBOL(qdisc_put_stab);
540 
541 static int qdisc_dump_stab(struct sk_buff *skb, struct qdisc_size_table *stab)
542 {
543 	struct nlattr *nest;
544 
545 	nest = nla_nest_start(skb, TCA_STAB);
546 	if (nest == NULL)
547 		goto nla_put_failure;
548 	if (nla_put(skb, TCA_STAB_BASE, sizeof(stab->szopts), &stab->szopts))
549 		goto nla_put_failure;
550 	nla_nest_end(skb, nest);
551 
552 	return skb->len;
553 
554 nla_put_failure:
555 	return -1;
556 }
557 
558 void __qdisc_calculate_pkt_len(struct sk_buff *skb,
559 			       const struct qdisc_size_table *stab)
560 {
561 	int pkt_len, slot;
562 
563 	pkt_len = skb->len + stab->szopts.overhead;
564 	if (unlikely(!stab->szopts.tsize))
565 		goto out;
566 
567 	slot = pkt_len + stab->szopts.cell_align;
568 	if (unlikely(slot < 0))
569 		slot = 0;
570 
571 	slot >>= stab->szopts.cell_log;
572 	if (likely(slot < stab->szopts.tsize))
573 		pkt_len = stab->data[slot];
574 	else
575 		pkt_len = stab->data[stab->szopts.tsize - 1] *
576 				(slot / stab->szopts.tsize) +
577 				stab->data[slot % stab->szopts.tsize];
578 
579 	pkt_len <<= stab->szopts.size_log;
580 out:
581 	if (unlikely(pkt_len < 1))
582 		pkt_len = 1;
583 	qdisc_skb_cb(skb)->pkt_len = pkt_len;
584 }
585 EXPORT_SYMBOL(__qdisc_calculate_pkt_len);
586 
587 void qdisc_warn_nonwc(const char *txt, struct Qdisc *qdisc)
588 {
589 	if (!(qdisc->flags & TCQ_F_WARN_NONWC)) {
590 		pr_warn("%s: %s qdisc %X: is non-work-conserving?\n",
591 			txt, qdisc->ops->id, qdisc->handle >> 16);
592 		qdisc->flags |= TCQ_F_WARN_NONWC;
593 	}
594 }
595 EXPORT_SYMBOL(qdisc_warn_nonwc);
596 
597 static enum hrtimer_restart qdisc_watchdog(struct hrtimer *timer)
598 {
599 	struct qdisc_watchdog *wd = container_of(timer, struct qdisc_watchdog,
600 						 timer);
601 
602 	rcu_read_lock();
603 	__netif_schedule(qdisc_root(wd->qdisc));
604 	rcu_read_unlock();
605 
606 	return HRTIMER_NORESTART;
607 }
608 
609 void qdisc_watchdog_init_clockid(struct qdisc_watchdog *wd, struct Qdisc *qdisc,
610 				 clockid_t clockid)
611 {
612 	hrtimer_init(&wd->timer, clockid, HRTIMER_MODE_ABS_PINNED);
613 	wd->timer.function = qdisc_watchdog;
614 	wd->qdisc = qdisc;
615 }
616 EXPORT_SYMBOL(qdisc_watchdog_init_clockid);
617 
618 void qdisc_watchdog_init(struct qdisc_watchdog *wd, struct Qdisc *qdisc)
619 {
620 	qdisc_watchdog_init_clockid(wd, qdisc, CLOCK_MONOTONIC);
621 }
622 EXPORT_SYMBOL(qdisc_watchdog_init);
623 
624 void qdisc_watchdog_schedule_ns(struct qdisc_watchdog *wd, u64 expires)
625 {
626 	if (test_bit(__QDISC_STATE_DEACTIVATED,
627 		     &qdisc_root_sleeping(wd->qdisc)->state))
628 		return;
629 
630 	if (wd->last_expires == expires)
631 		return;
632 
633 	wd->last_expires = expires;
634 	hrtimer_start(&wd->timer,
635 		      ns_to_ktime(expires),
636 		      HRTIMER_MODE_ABS_PINNED);
637 }
638 EXPORT_SYMBOL(qdisc_watchdog_schedule_ns);
639 
640 void qdisc_watchdog_cancel(struct qdisc_watchdog *wd)
641 {
642 	hrtimer_cancel(&wd->timer);
643 }
644 EXPORT_SYMBOL(qdisc_watchdog_cancel);
645 
646 static struct hlist_head *qdisc_class_hash_alloc(unsigned int n)
647 {
648 	struct hlist_head *h;
649 	unsigned int i;
650 
651 	h = kvmalloc_array(n, sizeof(struct hlist_head), GFP_KERNEL);
652 
653 	if (h != NULL) {
654 		for (i = 0; i < n; i++)
655 			INIT_HLIST_HEAD(&h[i]);
656 	}
657 	return h;
658 }
659 
660 void qdisc_class_hash_grow(struct Qdisc *sch, struct Qdisc_class_hash *clhash)
661 {
662 	struct Qdisc_class_common *cl;
663 	struct hlist_node *next;
664 	struct hlist_head *nhash, *ohash;
665 	unsigned int nsize, nmask, osize;
666 	unsigned int i, h;
667 
668 	/* Rehash when load factor exceeds 0.75 */
669 	if (clhash->hashelems * 4 <= clhash->hashsize * 3)
670 		return;
671 	nsize = clhash->hashsize * 2;
672 	nmask = nsize - 1;
673 	nhash = qdisc_class_hash_alloc(nsize);
674 	if (nhash == NULL)
675 		return;
676 
677 	ohash = clhash->hash;
678 	osize = clhash->hashsize;
679 
680 	sch_tree_lock(sch);
681 	for (i = 0; i < osize; i++) {
682 		hlist_for_each_entry_safe(cl, next, &ohash[i], hnode) {
683 			h = qdisc_class_hash(cl->classid, nmask);
684 			hlist_add_head(&cl->hnode, &nhash[h]);
685 		}
686 	}
687 	clhash->hash     = nhash;
688 	clhash->hashsize = nsize;
689 	clhash->hashmask = nmask;
690 	sch_tree_unlock(sch);
691 
692 	kvfree(ohash);
693 }
694 EXPORT_SYMBOL(qdisc_class_hash_grow);
695 
696 int qdisc_class_hash_init(struct Qdisc_class_hash *clhash)
697 {
698 	unsigned int size = 4;
699 
700 	clhash->hash = qdisc_class_hash_alloc(size);
701 	if (!clhash->hash)
702 		return -ENOMEM;
703 	clhash->hashsize  = size;
704 	clhash->hashmask  = size - 1;
705 	clhash->hashelems = 0;
706 	return 0;
707 }
708 EXPORT_SYMBOL(qdisc_class_hash_init);
709 
710 void qdisc_class_hash_destroy(struct Qdisc_class_hash *clhash)
711 {
712 	kvfree(clhash->hash);
713 }
714 EXPORT_SYMBOL(qdisc_class_hash_destroy);
715 
716 void qdisc_class_hash_insert(struct Qdisc_class_hash *clhash,
717 			     struct Qdisc_class_common *cl)
718 {
719 	unsigned int h;
720 
721 	INIT_HLIST_NODE(&cl->hnode);
722 	h = qdisc_class_hash(cl->classid, clhash->hashmask);
723 	hlist_add_head(&cl->hnode, &clhash->hash[h]);
724 	clhash->hashelems++;
725 }
726 EXPORT_SYMBOL(qdisc_class_hash_insert);
727 
728 void qdisc_class_hash_remove(struct Qdisc_class_hash *clhash,
729 			     struct Qdisc_class_common *cl)
730 {
731 	hlist_del(&cl->hnode);
732 	clhash->hashelems--;
733 }
734 EXPORT_SYMBOL(qdisc_class_hash_remove);
735 
736 /* Allocate an unique handle from space managed by kernel
737  * Possible range is [8000-FFFF]:0000 (0x8000 values)
738  */
739 static u32 qdisc_alloc_handle(struct net_device *dev)
740 {
741 	int i = 0x8000;
742 	static u32 autohandle = TC_H_MAKE(0x80000000U, 0);
743 
744 	do {
745 		autohandle += TC_H_MAKE(0x10000U, 0);
746 		if (autohandle == TC_H_MAKE(TC_H_ROOT, 0))
747 			autohandle = TC_H_MAKE(0x80000000U, 0);
748 		if (!qdisc_lookup(dev, autohandle))
749 			return autohandle;
750 		cond_resched();
751 	} while	(--i > 0);
752 
753 	return 0;
754 }
755 
756 void qdisc_tree_reduce_backlog(struct Qdisc *sch, int n, int len)
757 {
758 	bool qdisc_is_offloaded = sch->flags & TCQ_F_OFFLOADED;
759 	const struct Qdisc_class_ops *cops;
760 	unsigned long cl;
761 	u32 parentid;
762 	bool notify;
763 	int drops;
764 
765 	if (n == 0 && len == 0)
766 		return;
767 	drops = max_t(int, n, 0);
768 	rcu_read_lock();
769 	while ((parentid = sch->parent)) {
770 		if (TC_H_MAJ(parentid) == TC_H_MAJ(TC_H_INGRESS))
771 			break;
772 
773 		if (sch->flags & TCQ_F_NOPARENT)
774 			break;
775 		/* Notify parent qdisc only if child qdisc becomes empty.
776 		 *
777 		 * If child was empty even before update then backlog
778 		 * counter is screwed and we skip notification because
779 		 * parent class is already passive.
780 		 *
781 		 * If the original child was offloaded then it is allowed
782 		 * to be seem as empty, so the parent is notified anyway.
783 		 */
784 		notify = !sch->q.qlen && !WARN_ON_ONCE(!n &&
785 						       !qdisc_is_offloaded);
786 		/* TODO: perform the search on a per txq basis */
787 		sch = qdisc_lookup(qdisc_dev(sch), TC_H_MAJ(parentid));
788 		if (sch == NULL) {
789 			WARN_ON_ONCE(parentid != TC_H_ROOT);
790 			break;
791 		}
792 		cops = sch->ops->cl_ops;
793 		if (notify && cops->qlen_notify) {
794 			cl = cops->find(sch, parentid);
795 			cops->qlen_notify(sch, cl);
796 		}
797 		sch->q.qlen -= n;
798 		sch->qstats.backlog -= len;
799 		__qdisc_qstats_drop(sch, drops);
800 	}
801 	rcu_read_unlock();
802 }
803 EXPORT_SYMBOL(qdisc_tree_reduce_backlog);
804 
805 int qdisc_offload_dump_helper(struct Qdisc *sch, enum tc_setup_type type,
806 			      void *type_data)
807 {
808 	struct net_device *dev = qdisc_dev(sch);
809 	int err;
810 
811 	sch->flags &= ~TCQ_F_OFFLOADED;
812 	if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
813 		return 0;
814 
815 	err = dev->netdev_ops->ndo_setup_tc(dev, type, type_data);
816 	if (err == -EOPNOTSUPP)
817 		return 0;
818 
819 	if (!err)
820 		sch->flags |= TCQ_F_OFFLOADED;
821 
822 	return err;
823 }
824 EXPORT_SYMBOL(qdisc_offload_dump_helper);
825 
826 void qdisc_offload_graft_helper(struct net_device *dev, struct Qdisc *sch,
827 				struct Qdisc *new, struct Qdisc *old,
828 				enum tc_setup_type type, void *type_data,
829 				struct netlink_ext_ack *extack)
830 {
831 	bool any_qdisc_is_offloaded;
832 	int err;
833 
834 	if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
835 		return;
836 
837 	err = dev->netdev_ops->ndo_setup_tc(dev, type, type_data);
838 
839 	/* Don't report error if the graft is part of destroy operation. */
840 	if (!err || !new || new == &noop_qdisc)
841 		return;
842 
843 	/* Don't report error if the parent, the old child and the new
844 	 * one are not offloaded.
845 	 */
846 	any_qdisc_is_offloaded = new->flags & TCQ_F_OFFLOADED;
847 	any_qdisc_is_offloaded |= sch && sch->flags & TCQ_F_OFFLOADED;
848 	any_qdisc_is_offloaded |= old && old->flags & TCQ_F_OFFLOADED;
849 
850 	if (any_qdisc_is_offloaded)
851 		NL_SET_ERR_MSG(extack, "Offloading graft operation failed.");
852 }
853 EXPORT_SYMBOL(qdisc_offload_graft_helper);
854 
855 static void qdisc_offload_graft_root(struct net_device *dev,
856 				     struct Qdisc *new, struct Qdisc *old,
857 				     struct netlink_ext_ack *extack)
858 {
859 	struct tc_root_qopt_offload graft_offload = {
860 		.command	= TC_ROOT_GRAFT,
861 		.handle		= new ? new->handle : 0,
862 		.ingress	= (new && new->flags & TCQ_F_INGRESS) ||
863 				  (old && old->flags & TCQ_F_INGRESS),
864 	};
865 
866 	qdisc_offload_graft_helper(dev, NULL, new, old,
867 				   TC_SETUP_ROOT_QDISC, &graft_offload, extack);
868 }
869 
870 static int tc_fill_qdisc(struct sk_buff *skb, struct Qdisc *q, u32 clid,
871 			 u32 portid, u32 seq, u16 flags, int event)
872 {
873 	struct gnet_stats_basic_cpu __percpu *cpu_bstats = NULL;
874 	struct gnet_stats_queue __percpu *cpu_qstats = NULL;
875 	struct tcmsg *tcm;
876 	struct nlmsghdr  *nlh;
877 	unsigned char *b = skb_tail_pointer(skb);
878 	struct gnet_dump d;
879 	struct qdisc_size_table *stab;
880 	u32 block_index;
881 	__u32 qlen;
882 
883 	cond_resched();
884 	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*tcm), flags);
885 	if (!nlh)
886 		goto out_nlmsg_trim;
887 	tcm = nlmsg_data(nlh);
888 	tcm->tcm_family = AF_UNSPEC;
889 	tcm->tcm__pad1 = 0;
890 	tcm->tcm__pad2 = 0;
891 	tcm->tcm_ifindex = qdisc_dev(q)->ifindex;
892 	tcm->tcm_parent = clid;
893 	tcm->tcm_handle = q->handle;
894 	tcm->tcm_info = refcount_read(&q->refcnt);
895 	if (nla_put_string(skb, TCA_KIND, q->ops->id))
896 		goto nla_put_failure;
897 	if (q->ops->ingress_block_get) {
898 		block_index = q->ops->ingress_block_get(q);
899 		if (block_index &&
900 		    nla_put_u32(skb, TCA_INGRESS_BLOCK, block_index))
901 			goto nla_put_failure;
902 	}
903 	if (q->ops->egress_block_get) {
904 		block_index = q->ops->egress_block_get(q);
905 		if (block_index &&
906 		    nla_put_u32(skb, TCA_EGRESS_BLOCK, block_index))
907 			goto nla_put_failure;
908 	}
909 	if (q->ops->dump && q->ops->dump(q, skb) < 0)
910 		goto nla_put_failure;
911 	if (nla_put_u8(skb, TCA_HW_OFFLOAD, !!(q->flags & TCQ_F_OFFLOADED)))
912 		goto nla_put_failure;
913 	qlen = qdisc_qlen_sum(q);
914 
915 	stab = rtnl_dereference(q->stab);
916 	if (stab && qdisc_dump_stab(skb, stab) < 0)
917 		goto nla_put_failure;
918 
919 	if (gnet_stats_start_copy_compat(skb, TCA_STATS2, TCA_STATS, TCA_XSTATS,
920 					 NULL, &d, TCA_PAD) < 0)
921 		goto nla_put_failure;
922 
923 	if (q->ops->dump_stats && q->ops->dump_stats(q, &d) < 0)
924 		goto nla_put_failure;
925 
926 	if (qdisc_is_percpu_stats(q)) {
927 		cpu_bstats = q->cpu_bstats;
928 		cpu_qstats = q->cpu_qstats;
929 	}
930 
931 	if (gnet_stats_copy_basic(qdisc_root_sleeping_running(q),
932 				  &d, cpu_bstats, &q->bstats) < 0 ||
933 	    gnet_stats_copy_rate_est(&d, &q->rate_est) < 0 ||
934 	    gnet_stats_copy_queue(&d, cpu_qstats, &q->qstats, qlen) < 0)
935 		goto nla_put_failure;
936 
937 	if (gnet_stats_finish_copy(&d) < 0)
938 		goto nla_put_failure;
939 
940 	nlh->nlmsg_len = skb_tail_pointer(skb) - b;
941 	return skb->len;
942 
943 out_nlmsg_trim:
944 nla_put_failure:
945 	nlmsg_trim(skb, b);
946 	return -1;
947 }
948 
949 static bool tc_qdisc_dump_ignore(struct Qdisc *q, bool dump_invisible)
950 {
951 	if (q->flags & TCQ_F_BUILTIN)
952 		return true;
953 	if ((q->flags & TCQ_F_INVISIBLE) && !dump_invisible)
954 		return true;
955 
956 	return false;
957 }
958 
959 static int qdisc_notify(struct net *net, struct sk_buff *oskb,
960 			struct nlmsghdr *n, u32 clid,
961 			struct Qdisc *old, struct Qdisc *new)
962 {
963 	struct sk_buff *skb;
964 	u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
965 
966 	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
967 	if (!skb)
968 		return -ENOBUFS;
969 
970 	if (old && !tc_qdisc_dump_ignore(old, false)) {
971 		if (tc_fill_qdisc(skb, old, clid, portid, n->nlmsg_seq,
972 				  0, RTM_DELQDISC) < 0)
973 			goto err_out;
974 	}
975 	if (new && !tc_qdisc_dump_ignore(new, false)) {
976 		if (tc_fill_qdisc(skb, new, clid, portid, n->nlmsg_seq,
977 				  old ? NLM_F_REPLACE : 0, RTM_NEWQDISC) < 0)
978 			goto err_out;
979 	}
980 
981 	if (skb->len)
982 		return rtnetlink_send(skb, net, portid, RTNLGRP_TC,
983 				      n->nlmsg_flags & NLM_F_ECHO);
984 
985 err_out:
986 	kfree_skb(skb);
987 	return -EINVAL;
988 }
989 
990 static void notify_and_destroy(struct net *net, struct sk_buff *skb,
991 			       struct nlmsghdr *n, u32 clid,
992 			       struct Qdisc *old, struct Qdisc *new)
993 {
994 	if (new || old)
995 		qdisc_notify(net, skb, n, clid, old, new);
996 
997 	if (old)
998 		qdisc_put(old);
999 }
1000 
1001 /* Graft qdisc "new" to class "classid" of qdisc "parent" or
1002  * to device "dev".
1003  *
1004  * When appropriate send a netlink notification using 'skb'
1005  * and "n".
1006  *
1007  * On success, destroy old qdisc.
1008  */
1009 
1010 static int qdisc_graft(struct net_device *dev, struct Qdisc *parent,
1011 		       struct sk_buff *skb, struct nlmsghdr *n, u32 classid,
1012 		       struct Qdisc *new, struct Qdisc *old,
1013 		       struct netlink_ext_ack *extack)
1014 {
1015 	struct Qdisc *q = old;
1016 	struct net *net = dev_net(dev);
1017 
1018 	if (parent == NULL) {
1019 		unsigned int i, num_q, ingress;
1020 
1021 		ingress = 0;
1022 		num_q = dev->num_tx_queues;
1023 		if ((q && q->flags & TCQ_F_INGRESS) ||
1024 		    (new && new->flags & TCQ_F_INGRESS)) {
1025 			num_q = 1;
1026 			ingress = 1;
1027 			if (!dev_ingress_queue(dev)) {
1028 				NL_SET_ERR_MSG(extack, "Device does not have an ingress queue");
1029 				return -ENOENT;
1030 			}
1031 		}
1032 
1033 		if (dev->flags & IFF_UP)
1034 			dev_deactivate(dev);
1035 
1036 		qdisc_offload_graft_root(dev, new, old, extack);
1037 
1038 		if (new && new->ops->attach)
1039 			goto skip;
1040 
1041 		for (i = 0; i < num_q; i++) {
1042 			struct netdev_queue *dev_queue = dev_ingress_queue(dev);
1043 
1044 			if (!ingress)
1045 				dev_queue = netdev_get_tx_queue(dev, i);
1046 
1047 			old = dev_graft_qdisc(dev_queue, new);
1048 			if (new && i > 0)
1049 				qdisc_refcount_inc(new);
1050 
1051 			if (!ingress)
1052 				qdisc_put(old);
1053 		}
1054 
1055 skip:
1056 		if (!ingress) {
1057 			notify_and_destroy(net, skb, n, classid,
1058 					   dev->qdisc, new);
1059 			if (new && !new->ops->attach)
1060 				qdisc_refcount_inc(new);
1061 			dev->qdisc = new ? : &noop_qdisc;
1062 
1063 			if (new && new->ops->attach)
1064 				new->ops->attach(new);
1065 		} else {
1066 			notify_and_destroy(net, skb, n, classid, old, new);
1067 		}
1068 
1069 		if (dev->flags & IFF_UP)
1070 			dev_activate(dev);
1071 	} else {
1072 		const struct Qdisc_class_ops *cops = parent->ops->cl_ops;
1073 		unsigned long cl;
1074 		int err;
1075 
1076 		/* Only support running class lockless if parent is lockless */
1077 		if (new && (new->flags & TCQ_F_NOLOCK) &&
1078 		    parent && !(parent->flags & TCQ_F_NOLOCK))
1079 			new->flags &= ~TCQ_F_NOLOCK;
1080 
1081 		if (!cops || !cops->graft)
1082 			return -EOPNOTSUPP;
1083 
1084 		cl = cops->find(parent, classid);
1085 		if (!cl) {
1086 			NL_SET_ERR_MSG(extack, "Specified class not found");
1087 			return -ENOENT;
1088 		}
1089 
1090 		err = cops->graft(parent, cl, new, &old, extack);
1091 		if (err)
1092 			return err;
1093 		notify_and_destroy(net, skb, n, classid, old, new);
1094 	}
1095 	return 0;
1096 }
1097 
1098 static int qdisc_block_indexes_set(struct Qdisc *sch, struct nlattr **tca,
1099 				   struct netlink_ext_ack *extack)
1100 {
1101 	u32 block_index;
1102 
1103 	if (tca[TCA_INGRESS_BLOCK]) {
1104 		block_index = nla_get_u32(tca[TCA_INGRESS_BLOCK]);
1105 
1106 		if (!block_index) {
1107 			NL_SET_ERR_MSG(extack, "Ingress block index cannot be 0");
1108 			return -EINVAL;
1109 		}
1110 		if (!sch->ops->ingress_block_set) {
1111 			NL_SET_ERR_MSG(extack, "Ingress block sharing is not supported");
1112 			return -EOPNOTSUPP;
1113 		}
1114 		sch->ops->ingress_block_set(sch, block_index);
1115 	}
1116 	if (tca[TCA_EGRESS_BLOCK]) {
1117 		block_index = nla_get_u32(tca[TCA_EGRESS_BLOCK]);
1118 
1119 		if (!block_index) {
1120 			NL_SET_ERR_MSG(extack, "Egress block index cannot be 0");
1121 			return -EINVAL;
1122 		}
1123 		if (!sch->ops->egress_block_set) {
1124 			NL_SET_ERR_MSG(extack, "Egress block sharing is not supported");
1125 			return -EOPNOTSUPP;
1126 		}
1127 		sch->ops->egress_block_set(sch, block_index);
1128 	}
1129 	return 0;
1130 }
1131 
1132 /*
1133    Allocate and initialize new qdisc.
1134 
1135    Parameters are passed via opt.
1136  */
1137 
1138 static struct Qdisc *qdisc_create(struct net_device *dev,
1139 				  struct netdev_queue *dev_queue,
1140 				  struct Qdisc *p, u32 parent, u32 handle,
1141 				  struct nlattr **tca, int *errp,
1142 				  struct netlink_ext_ack *extack)
1143 {
1144 	int err;
1145 	struct nlattr *kind = tca[TCA_KIND];
1146 	struct Qdisc *sch;
1147 	struct Qdisc_ops *ops;
1148 	struct qdisc_size_table *stab;
1149 
1150 	ops = qdisc_lookup_ops(kind);
1151 #ifdef CONFIG_MODULES
1152 	if (ops == NULL && kind != NULL) {
1153 		char name[IFNAMSIZ];
1154 		if (nla_strlcpy(name, kind, IFNAMSIZ) < IFNAMSIZ) {
1155 			/* We dropped the RTNL semaphore in order to
1156 			 * perform the module load.  So, even if we
1157 			 * succeeded in loading the module we have to
1158 			 * tell the caller to replay the request.  We
1159 			 * indicate this using -EAGAIN.
1160 			 * We replay the request because the device may
1161 			 * go away in the mean time.
1162 			 */
1163 			rtnl_unlock();
1164 			request_module("sch_%s", name);
1165 			rtnl_lock();
1166 			ops = qdisc_lookup_ops(kind);
1167 			if (ops != NULL) {
1168 				/* We will try again qdisc_lookup_ops,
1169 				 * so don't keep a reference.
1170 				 */
1171 				module_put(ops->owner);
1172 				err = -EAGAIN;
1173 				goto err_out;
1174 			}
1175 		}
1176 	}
1177 #endif
1178 
1179 	err = -ENOENT;
1180 	if (!ops) {
1181 		NL_SET_ERR_MSG(extack, "Specified qdisc not found");
1182 		goto err_out;
1183 	}
1184 
1185 	sch = qdisc_alloc(dev_queue, ops, extack);
1186 	if (IS_ERR(sch)) {
1187 		err = PTR_ERR(sch);
1188 		goto err_out2;
1189 	}
1190 
1191 	sch->parent = parent;
1192 
1193 	if (handle == TC_H_INGRESS) {
1194 		sch->flags |= TCQ_F_INGRESS;
1195 		handle = TC_H_MAKE(TC_H_INGRESS, 0);
1196 	} else {
1197 		if (handle == 0) {
1198 			handle = qdisc_alloc_handle(dev);
1199 			if (handle == 0) {
1200 				NL_SET_ERR_MSG(extack, "Maximum number of qdisc handles was exceeded");
1201 				err = -ENOSPC;
1202 				goto err_out3;
1203 			}
1204 		}
1205 		if (!netif_is_multiqueue(dev))
1206 			sch->flags |= TCQ_F_ONETXQUEUE;
1207 	}
1208 
1209 	sch->handle = handle;
1210 
1211 	/* This exist to keep backward compatible with a userspace
1212 	 * loophole, what allowed userspace to get IFF_NO_QUEUE
1213 	 * facility on older kernels by setting tx_queue_len=0 (prior
1214 	 * to qdisc init), and then forgot to reinit tx_queue_len
1215 	 * before again attaching a qdisc.
1216 	 */
1217 	if ((dev->priv_flags & IFF_NO_QUEUE) && (dev->tx_queue_len == 0)) {
1218 		dev->tx_queue_len = DEFAULT_TX_QUEUE_LEN;
1219 		netdev_info(dev, "Caught tx_queue_len zero misconfig\n");
1220 	}
1221 
1222 	err = qdisc_block_indexes_set(sch, tca, extack);
1223 	if (err)
1224 		goto err_out3;
1225 
1226 	if (ops->init) {
1227 		err = ops->init(sch, tca[TCA_OPTIONS], extack);
1228 		if (err != 0)
1229 			goto err_out5;
1230 	}
1231 
1232 	if (tca[TCA_STAB]) {
1233 		stab = qdisc_get_stab(tca[TCA_STAB], extack);
1234 		if (IS_ERR(stab)) {
1235 			err = PTR_ERR(stab);
1236 			goto err_out4;
1237 		}
1238 		rcu_assign_pointer(sch->stab, stab);
1239 	}
1240 	if (tca[TCA_RATE]) {
1241 		seqcount_t *running;
1242 
1243 		err = -EOPNOTSUPP;
1244 		if (sch->flags & TCQ_F_MQROOT) {
1245 			NL_SET_ERR_MSG(extack, "Cannot attach rate estimator to a multi-queue root qdisc");
1246 			goto err_out4;
1247 		}
1248 
1249 		if (sch->parent != TC_H_ROOT &&
1250 		    !(sch->flags & TCQ_F_INGRESS) &&
1251 		    (!p || !(p->flags & TCQ_F_MQROOT)))
1252 			running = qdisc_root_sleeping_running(sch);
1253 		else
1254 			running = &sch->running;
1255 
1256 		err = gen_new_estimator(&sch->bstats,
1257 					sch->cpu_bstats,
1258 					&sch->rate_est,
1259 					NULL,
1260 					running,
1261 					tca[TCA_RATE]);
1262 		if (err) {
1263 			NL_SET_ERR_MSG(extack, "Failed to generate new estimator");
1264 			goto err_out4;
1265 		}
1266 	}
1267 
1268 	qdisc_hash_add(sch, false);
1269 
1270 	return sch;
1271 
1272 err_out5:
1273 	/* ops->init() failed, we call ->destroy() like qdisc_create_dflt() */
1274 	if (ops->destroy)
1275 		ops->destroy(sch);
1276 err_out3:
1277 	dev_put(dev);
1278 	qdisc_free(sch);
1279 err_out2:
1280 	module_put(ops->owner);
1281 err_out:
1282 	*errp = err;
1283 	return NULL;
1284 
1285 err_out4:
1286 	/*
1287 	 * Any broken qdiscs that would require a ops->reset() here?
1288 	 * The qdisc was never in action so it shouldn't be necessary.
1289 	 */
1290 	qdisc_put_stab(rtnl_dereference(sch->stab));
1291 	if (ops->destroy)
1292 		ops->destroy(sch);
1293 	goto err_out3;
1294 }
1295 
1296 static int qdisc_change(struct Qdisc *sch, struct nlattr **tca,
1297 			struct netlink_ext_ack *extack)
1298 {
1299 	struct qdisc_size_table *ostab, *stab = NULL;
1300 	int err = 0;
1301 
1302 	if (tca[TCA_OPTIONS]) {
1303 		if (!sch->ops->change) {
1304 			NL_SET_ERR_MSG(extack, "Change operation not supported by specified qdisc");
1305 			return -EINVAL;
1306 		}
1307 		if (tca[TCA_INGRESS_BLOCK] || tca[TCA_EGRESS_BLOCK]) {
1308 			NL_SET_ERR_MSG(extack, "Change of blocks is not supported");
1309 			return -EOPNOTSUPP;
1310 		}
1311 		err = sch->ops->change(sch, tca[TCA_OPTIONS], extack);
1312 		if (err)
1313 			return err;
1314 	}
1315 
1316 	if (tca[TCA_STAB]) {
1317 		stab = qdisc_get_stab(tca[TCA_STAB], extack);
1318 		if (IS_ERR(stab))
1319 			return PTR_ERR(stab);
1320 	}
1321 
1322 	ostab = rtnl_dereference(sch->stab);
1323 	rcu_assign_pointer(sch->stab, stab);
1324 	qdisc_put_stab(ostab);
1325 
1326 	if (tca[TCA_RATE]) {
1327 		/* NB: ignores errors from replace_estimator
1328 		   because change can't be undone. */
1329 		if (sch->flags & TCQ_F_MQROOT)
1330 			goto out;
1331 		gen_replace_estimator(&sch->bstats,
1332 				      sch->cpu_bstats,
1333 				      &sch->rate_est,
1334 				      NULL,
1335 				      qdisc_root_sleeping_running(sch),
1336 				      tca[TCA_RATE]);
1337 	}
1338 out:
1339 	return 0;
1340 }
1341 
1342 struct check_loop_arg {
1343 	struct qdisc_walker	w;
1344 	struct Qdisc		*p;
1345 	int			depth;
1346 };
1347 
1348 static int check_loop_fn(struct Qdisc *q, unsigned long cl,
1349 			 struct qdisc_walker *w);
1350 
1351 static int check_loop(struct Qdisc *q, struct Qdisc *p, int depth)
1352 {
1353 	struct check_loop_arg	arg;
1354 
1355 	if (q->ops->cl_ops == NULL)
1356 		return 0;
1357 
1358 	arg.w.stop = arg.w.skip = arg.w.count = 0;
1359 	arg.w.fn = check_loop_fn;
1360 	arg.depth = depth;
1361 	arg.p = p;
1362 	q->ops->cl_ops->walk(q, &arg.w);
1363 	return arg.w.stop ? -ELOOP : 0;
1364 }
1365 
1366 static int
1367 check_loop_fn(struct Qdisc *q, unsigned long cl, struct qdisc_walker *w)
1368 {
1369 	struct Qdisc *leaf;
1370 	const struct Qdisc_class_ops *cops = q->ops->cl_ops;
1371 	struct check_loop_arg *arg = (struct check_loop_arg *)w;
1372 
1373 	leaf = cops->leaf(q, cl);
1374 	if (leaf) {
1375 		if (leaf == arg->p || arg->depth > 7)
1376 			return -ELOOP;
1377 		return check_loop(leaf, arg->p, arg->depth + 1);
1378 	}
1379 	return 0;
1380 }
1381 
1382 const struct nla_policy rtm_tca_policy[TCA_MAX + 1] = {
1383 	[TCA_KIND]		= { .type = NLA_STRING },
1384 	[TCA_RATE]		= { .type = NLA_BINARY,
1385 				    .len = sizeof(struct tc_estimator) },
1386 	[TCA_STAB]		= { .type = NLA_NESTED },
1387 	[TCA_DUMP_INVISIBLE]	= { .type = NLA_FLAG },
1388 	[TCA_CHAIN]		= { .type = NLA_U32 },
1389 	[TCA_INGRESS_BLOCK]	= { .type = NLA_U32 },
1390 	[TCA_EGRESS_BLOCK]	= { .type = NLA_U32 },
1391 };
1392 
1393 /*
1394  * Delete/get qdisc.
1395  */
1396 
1397 static int tc_get_qdisc(struct sk_buff *skb, struct nlmsghdr *n,
1398 			struct netlink_ext_ack *extack)
1399 {
1400 	struct net *net = sock_net(skb->sk);
1401 	struct tcmsg *tcm = nlmsg_data(n);
1402 	struct nlattr *tca[TCA_MAX + 1];
1403 	struct net_device *dev;
1404 	u32 clid;
1405 	struct Qdisc *q = NULL;
1406 	struct Qdisc *p = NULL;
1407 	int err;
1408 
1409 	if ((n->nlmsg_type != RTM_GETQDISC) &&
1410 	    !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
1411 		return -EPERM;
1412 
1413 	err = nlmsg_parse(n, sizeof(*tcm), tca, TCA_MAX, rtm_tca_policy,
1414 			  extack);
1415 	if (err < 0)
1416 		return err;
1417 
1418 	dev = __dev_get_by_index(net, tcm->tcm_ifindex);
1419 	if (!dev)
1420 		return -ENODEV;
1421 
1422 	clid = tcm->tcm_parent;
1423 	if (clid) {
1424 		if (clid != TC_H_ROOT) {
1425 			if (TC_H_MAJ(clid) != TC_H_MAJ(TC_H_INGRESS)) {
1426 				p = qdisc_lookup(dev, TC_H_MAJ(clid));
1427 				if (!p) {
1428 					NL_SET_ERR_MSG(extack, "Failed to find qdisc with specified classid");
1429 					return -ENOENT;
1430 				}
1431 				q = qdisc_leaf(p, clid);
1432 			} else if (dev_ingress_queue(dev)) {
1433 				q = dev_ingress_queue(dev)->qdisc_sleeping;
1434 			}
1435 		} else {
1436 			q = dev->qdisc;
1437 		}
1438 		if (!q) {
1439 			NL_SET_ERR_MSG(extack, "Cannot find specified qdisc on specified device");
1440 			return -ENOENT;
1441 		}
1442 
1443 		if (tcm->tcm_handle && q->handle != tcm->tcm_handle) {
1444 			NL_SET_ERR_MSG(extack, "Invalid handle");
1445 			return -EINVAL;
1446 		}
1447 	} else {
1448 		q = qdisc_lookup(dev, tcm->tcm_handle);
1449 		if (!q) {
1450 			NL_SET_ERR_MSG(extack, "Failed to find qdisc with specified handle");
1451 			return -ENOENT;
1452 		}
1453 	}
1454 
1455 	if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], q->ops->id)) {
1456 		NL_SET_ERR_MSG(extack, "Invalid qdisc name");
1457 		return -EINVAL;
1458 	}
1459 
1460 	if (n->nlmsg_type == RTM_DELQDISC) {
1461 		if (!clid) {
1462 			NL_SET_ERR_MSG(extack, "Classid cannot be zero");
1463 			return -EINVAL;
1464 		}
1465 		if (q->handle == 0) {
1466 			NL_SET_ERR_MSG(extack, "Cannot delete qdisc with handle of zero");
1467 			return -ENOENT;
1468 		}
1469 		err = qdisc_graft(dev, p, skb, n, clid, NULL, q, extack);
1470 		if (err != 0)
1471 			return err;
1472 	} else {
1473 		qdisc_notify(net, skb, n, clid, NULL, q);
1474 	}
1475 	return 0;
1476 }
1477 
1478 /*
1479  * Create/change qdisc.
1480  */
1481 
1482 static int tc_modify_qdisc(struct sk_buff *skb, struct nlmsghdr *n,
1483 			   struct netlink_ext_ack *extack)
1484 {
1485 	struct net *net = sock_net(skb->sk);
1486 	struct tcmsg *tcm;
1487 	struct nlattr *tca[TCA_MAX + 1];
1488 	struct net_device *dev;
1489 	u32 clid;
1490 	struct Qdisc *q, *p;
1491 	int err;
1492 
1493 	if (!netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
1494 		return -EPERM;
1495 
1496 replay:
1497 	/* Reinit, just in case something touches this. */
1498 	err = nlmsg_parse(n, sizeof(*tcm), tca, TCA_MAX, rtm_tca_policy,
1499 			  extack);
1500 	if (err < 0)
1501 		return err;
1502 
1503 	tcm = nlmsg_data(n);
1504 	clid = tcm->tcm_parent;
1505 	q = p = NULL;
1506 
1507 	dev = __dev_get_by_index(net, tcm->tcm_ifindex);
1508 	if (!dev)
1509 		return -ENODEV;
1510 
1511 
1512 	if (clid) {
1513 		if (clid != TC_H_ROOT) {
1514 			if (clid != TC_H_INGRESS) {
1515 				p = qdisc_lookup(dev, TC_H_MAJ(clid));
1516 				if (!p) {
1517 					NL_SET_ERR_MSG(extack, "Failed to find specified qdisc");
1518 					return -ENOENT;
1519 				}
1520 				q = qdisc_leaf(p, clid);
1521 			} else if (dev_ingress_queue_create(dev)) {
1522 				q = dev_ingress_queue(dev)->qdisc_sleeping;
1523 			}
1524 		} else {
1525 			q = dev->qdisc;
1526 		}
1527 
1528 		/* It may be default qdisc, ignore it */
1529 		if (q && q->handle == 0)
1530 			q = NULL;
1531 
1532 		if (!q || !tcm->tcm_handle || q->handle != tcm->tcm_handle) {
1533 			if (tcm->tcm_handle) {
1534 				if (q && !(n->nlmsg_flags & NLM_F_REPLACE)) {
1535 					NL_SET_ERR_MSG(extack, "NLM_F_REPLACE needed to override");
1536 					return -EEXIST;
1537 				}
1538 				if (TC_H_MIN(tcm->tcm_handle)) {
1539 					NL_SET_ERR_MSG(extack, "Invalid minor handle");
1540 					return -EINVAL;
1541 				}
1542 				q = qdisc_lookup(dev, tcm->tcm_handle);
1543 				if (!q)
1544 					goto create_n_graft;
1545 				if (n->nlmsg_flags & NLM_F_EXCL) {
1546 					NL_SET_ERR_MSG(extack, "Exclusivity flag on, cannot override");
1547 					return -EEXIST;
1548 				}
1549 				if (tca[TCA_KIND] &&
1550 				    nla_strcmp(tca[TCA_KIND], q->ops->id)) {
1551 					NL_SET_ERR_MSG(extack, "Invalid qdisc name");
1552 					return -EINVAL;
1553 				}
1554 				if (q == p ||
1555 				    (p && check_loop(q, p, 0))) {
1556 					NL_SET_ERR_MSG(extack, "Qdisc parent/child loop detected");
1557 					return -ELOOP;
1558 				}
1559 				qdisc_refcount_inc(q);
1560 				goto graft;
1561 			} else {
1562 				if (!q)
1563 					goto create_n_graft;
1564 
1565 				/* This magic test requires explanation.
1566 				 *
1567 				 *   We know, that some child q is already
1568 				 *   attached to this parent and have choice:
1569 				 *   either to change it or to create/graft new one.
1570 				 *
1571 				 *   1. We are allowed to create/graft only
1572 				 *   if CREATE and REPLACE flags are set.
1573 				 *
1574 				 *   2. If EXCL is set, requestor wanted to say,
1575 				 *   that qdisc tcm_handle is not expected
1576 				 *   to exist, so that we choose create/graft too.
1577 				 *
1578 				 *   3. The last case is when no flags are set.
1579 				 *   Alas, it is sort of hole in API, we
1580 				 *   cannot decide what to do unambiguously.
1581 				 *   For now we select create/graft, if
1582 				 *   user gave KIND, which does not match existing.
1583 				 */
1584 				if ((n->nlmsg_flags & NLM_F_CREATE) &&
1585 				    (n->nlmsg_flags & NLM_F_REPLACE) &&
1586 				    ((n->nlmsg_flags & NLM_F_EXCL) ||
1587 				     (tca[TCA_KIND] &&
1588 				      nla_strcmp(tca[TCA_KIND], q->ops->id))))
1589 					goto create_n_graft;
1590 			}
1591 		}
1592 	} else {
1593 		if (!tcm->tcm_handle) {
1594 			NL_SET_ERR_MSG(extack, "Handle cannot be zero");
1595 			return -EINVAL;
1596 		}
1597 		q = qdisc_lookup(dev, tcm->tcm_handle);
1598 	}
1599 
1600 	/* Change qdisc parameters */
1601 	if (!q) {
1602 		NL_SET_ERR_MSG(extack, "Specified qdisc not found");
1603 		return -ENOENT;
1604 	}
1605 	if (n->nlmsg_flags & NLM_F_EXCL) {
1606 		NL_SET_ERR_MSG(extack, "Exclusivity flag on, cannot modify");
1607 		return -EEXIST;
1608 	}
1609 	if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], q->ops->id)) {
1610 		NL_SET_ERR_MSG(extack, "Invalid qdisc name");
1611 		return -EINVAL;
1612 	}
1613 	err = qdisc_change(q, tca, extack);
1614 	if (err == 0)
1615 		qdisc_notify(net, skb, n, clid, NULL, q);
1616 	return err;
1617 
1618 create_n_graft:
1619 	if (!(n->nlmsg_flags & NLM_F_CREATE)) {
1620 		NL_SET_ERR_MSG(extack, "Qdisc not found. To create specify NLM_F_CREATE flag");
1621 		return -ENOENT;
1622 	}
1623 	if (clid == TC_H_INGRESS) {
1624 		if (dev_ingress_queue(dev)) {
1625 			q = qdisc_create(dev, dev_ingress_queue(dev), p,
1626 					 tcm->tcm_parent, tcm->tcm_parent,
1627 					 tca, &err, extack);
1628 		} else {
1629 			NL_SET_ERR_MSG(extack, "Cannot find ingress queue for specified device");
1630 			err = -ENOENT;
1631 		}
1632 	} else {
1633 		struct netdev_queue *dev_queue;
1634 
1635 		if (p && p->ops->cl_ops && p->ops->cl_ops->select_queue)
1636 			dev_queue = p->ops->cl_ops->select_queue(p, tcm);
1637 		else if (p)
1638 			dev_queue = p->dev_queue;
1639 		else
1640 			dev_queue = netdev_get_tx_queue(dev, 0);
1641 
1642 		q = qdisc_create(dev, dev_queue, p,
1643 				 tcm->tcm_parent, tcm->tcm_handle,
1644 				 tca, &err, extack);
1645 	}
1646 	if (q == NULL) {
1647 		if (err == -EAGAIN)
1648 			goto replay;
1649 		return err;
1650 	}
1651 
1652 graft:
1653 	err = qdisc_graft(dev, p, skb, n, clid, q, NULL, extack);
1654 	if (err) {
1655 		if (q)
1656 			qdisc_put(q);
1657 		return err;
1658 	}
1659 
1660 	return 0;
1661 }
1662 
1663 static int tc_dump_qdisc_root(struct Qdisc *root, struct sk_buff *skb,
1664 			      struct netlink_callback *cb,
1665 			      int *q_idx_p, int s_q_idx, bool recur,
1666 			      bool dump_invisible)
1667 {
1668 	int ret = 0, q_idx = *q_idx_p;
1669 	struct Qdisc *q;
1670 	int b;
1671 
1672 	if (!root)
1673 		return 0;
1674 
1675 	q = root;
1676 	if (q_idx < s_q_idx) {
1677 		q_idx++;
1678 	} else {
1679 		if (!tc_qdisc_dump_ignore(q, dump_invisible) &&
1680 		    tc_fill_qdisc(skb, q, q->parent, NETLINK_CB(cb->skb).portid,
1681 				  cb->nlh->nlmsg_seq, NLM_F_MULTI,
1682 				  RTM_NEWQDISC) <= 0)
1683 			goto done;
1684 		q_idx++;
1685 	}
1686 
1687 	/* If dumping singletons, there is no qdisc_dev(root) and the singleton
1688 	 * itself has already been dumped.
1689 	 *
1690 	 * If we've already dumped the top-level (ingress) qdisc above and the global
1691 	 * qdisc hashtable, we don't want to hit it again
1692 	 */
1693 	if (!qdisc_dev(root) || !recur)
1694 		goto out;
1695 
1696 	hash_for_each(qdisc_dev(root)->qdisc_hash, b, q, hash) {
1697 		if (q_idx < s_q_idx) {
1698 			q_idx++;
1699 			continue;
1700 		}
1701 		if (!tc_qdisc_dump_ignore(q, dump_invisible) &&
1702 		    tc_fill_qdisc(skb, q, q->parent, NETLINK_CB(cb->skb).portid,
1703 				  cb->nlh->nlmsg_seq, NLM_F_MULTI,
1704 				  RTM_NEWQDISC) <= 0)
1705 			goto done;
1706 		q_idx++;
1707 	}
1708 
1709 out:
1710 	*q_idx_p = q_idx;
1711 	return ret;
1712 done:
1713 	ret = -1;
1714 	goto out;
1715 }
1716 
1717 static int tc_dump_qdisc(struct sk_buff *skb, struct netlink_callback *cb)
1718 {
1719 	struct net *net = sock_net(skb->sk);
1720 	int idx, q_idx;
1721 	int s_idx, s_q_idx;
1722 	struct net_device *dev;
1723 	const struct nlmsghdr *nlh = cb->nlh;
1724 	struct nlattr *tca[TCA_MAX + 1];
1725 	int err;
1726 
1727 	s_idx = cb->args[0];
1728 	s_q_idx = q_idx = cb->args[1];
1729 
1730 	idx = 0;
1731 	ASSERT_RTNL();
1732 
1733 	err = nlmsg_parse(nlh, sizeof(struct tcmsg), tca, TCA_MAX,
1734 			  rtm_tca_policy, cb->extack);
1735 	if (err < 0)
1736 		return err;
1737 
1738 	for_each_netdev(net, dev) {
1739 		struct netdev_queue *dev_queue;
1740 
1741 		if (idx < s_idx)
1742 			goto cont;
1743 		if (idx > s_idx)
1744 			s_q_idx = 0;
1745 		q_idx = 0;
1746 
1747 		if (tc_dump_qdisc_root(dev->qdisc, skb, cb, &q_idx, s_q_idx,
1748 				       true, tca[TCA_DUMP_INVISIBLE]) < 0)
1749 			goto done;
1750 
1751 		dev_queue = dev_ingress_queue(dev);
1752 		if (dev_queue &&
1753 		    tc_dump_qdisc_root(dev_queue->qdisc_sleeping, skb, cb,
1754 				       &q_idx, s_q_idx, false,
1755 				       tca[TCA_DUMP_INVISIBLE]) < 0)
1756 			goto done;
1757 
1758 cont:
1759 		idx++;
1760 	}
1761 
1762 done:
1763 	cb->args[0] = idx;
1764 	cb->args[1] = q_idx;
1765 
1766 	return skb->len;
1767 }
1768 
1769 
1770 
1771 /************************************************
1772  *	Traffic classes manipulation.		*
1773  ************************************************/
1774 
1775 static int tc_fill_tclass(struct sk_buff *skb, struct Qdisc *q,
1776 			  unsigned long cl,
1777 			  u32 portid, u32 seq, u16 flags, int event)
1778 {
1779 	struct tcmsg *tcm;
1780 	struct nlmsghdr  *nlh;
1781 	unsigned char *b = skb_tail_pointer(skb);
1782 	struct gnet_dump d;
1783 	const struct Qdisc_class_ops *cl_ops = q->ops->cl_ops;
1784 
1785 	cond_resched();
1786 	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*tcm), flags);
1787 	if (!nlh)
1788 		goto out_nlmsg_trim;
1789 	tcm = nlmsg_data(nlh);
1790 	tcm->tcm_family = AF_UNSPEC;
1791 	tcm->tcm__pad1 = 0;
1792 	tcm->tcm__pad2 = 0;
1793 	tcm->tcm_ifindex = qdisc_dev(q)->ifindex;
1794 	tcm->tcm_parent = q->handle;
1795 	tcm->tcm_handle = q->handle;
1796 	tcm->tcm_info = 0;
1797 	if (nla_put_string(skb, TCA_KIND, q->ops->id))
1798 		goto nla_put_failure;
1799 	if (cl_ops->dump && cl_ops->dump(q, cl, skb, tcm) < 0)
1800 		goto nla_put_failure;
1801 
1802 	if (gnet_stats_start_copy_compat(skb, TCA_STATS2, TCA_STATS, TCA_XSTATS,
1803 					 NULL, &d, TCA_PAD) < 0)
1804 		goto nla_put_failure;
1805 
1806 	if (cl_ops->dump_stats && cl_ops->dump_stats(q, cl, &d) < 0)
1807 		goto nla_put_failure;
1808 
1809 	if (gnet_stats_finish_copy(&d) < 0)
1810 		goto nla_put_failure;
1811 
1812 	nlh->nlmsg_len = skb_tail_pointer(skb) - b;
1813 	return skb->len;
1814 
1815 out_nlmsg_trim:
1816 nla_put_failure:
1817 	nlmsg_trim(skb, b);
1818 	return -1;
1819 }
1820 
1821 static int tclass_notify(struct net *net, struct sk_buff *oskb,
1822 			 struct nlmsghdr *n, struct Qdisc *q,
1823 			 unsigned long cl, int event)
1824 {
1825 	struct sk_buff *skb;
1826 	u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
1827 	int err = 0;
1828 
1829 	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
1830 	if (!skb)
1831 		return -ENOBUFS;
1832 
1833 	if (tc_fill_tclass(skb, q, cl, portid, n->nlmsg_seq, 0, event) < 0) {
1834 		kfree_skb(skb);
1835 		return -EINVAL;
1836 	}
1837 
1838 	err = rtnetlink_send(skb, net, portid, RTNLGRP_TC,
1839 			     n->nlmsg_flags & NLM_F_ECHO);
1840 	if (err > 0)
1841 		err = 0;
1842 	return err;
1843 }
1844 
1845 static int tclass_del_notify(struct net *net,
1846 			     const struct Qdisc_class_ops *cops,
1847 			     struct sk_buff *oskb, struct nlmsghdr *n,
1848 			     struct Qdisc *q, unsigned long cl)
1849 {
1850 	u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
1851 	struct sk_buff *skb;
1852 	int err = 0;
1853 
1854 	if (!cops->delete)
1855 		return -EOPNOTSUPP;
1856 
1857 	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
1858 	if (!skb)
1859 		return -ENOBUFS;
1860 
1861 	if (tc_fill_tclass(skb, q, cl, portid, n->nlmsg_seq, 0,
1862 			   RTM_DELTCLASS) < 0) {
1863 		kfree_skb(skb);
1864 		return -EINVAL;
1865 	}
1866 
1867 	err = cops->delete(q, cl);
1868 	if (err) {
1869 		kfree_skb(skb);
1870 		return err;
1871 	}
1872 
1873 	err = rtnetlink_send(skb, net, portid, RTNLGRP_TC,
1874 			     n->nlmsg_flags & NLM_F_ECHO);
1875 	if (err > 0)
1876 		err = 0;
1877 	return err;
1878 }
1879 
1880 #ifdef CONFIG_NET_CLS
1881 
1882 struct tcf_bind_args {
1883 	struct tcf_walker w;
1884 	u32 classid;
1885 	unsigned long cl;
1886 };
1887 
1888 static int tcf_node_bind(struct tcf_proto *tp, void *n, struct tcf_walker *arg)
1889 {
1890 	struct tcf_bind_args *a = (void *)arg;
1891 
1892 	if (tp->ops->bind_class) {
1893 		struct Qdisc *q = tcf_block_q(tp->chain->block);
1894 
1895 		sch_tree_lock(q);
1896 		tp->ops->bind_class(n, a->classid, a->cl);
1897 		sch_tree_unlock(q);
1898 	}
1899 	return 0;
1900 }
1901 
1902 static void tc_bind_tclass(struct Qdisc *q, u32 portid, u32 clid,
1903 			   unsigned long new_cl)
1904 {
1905 	const struct Qdisc_class_ops *cops = q->ops->cl_ops;
1906 	struct tcf_block *block;
1907 	struct tcf_chain *chain;
1908 	unsigned long cl;
1909 
1910 	cl = cops->find(q, portid);
1911 	if (!cl)
1912 		return;
1913 	block = cops->tcf_block(q, cl, NULL);
1914 	if (!block)
1915 		return;
1916 	for (chain = tcf_get_next_chain(block, NULL);
1917 	     chain;
1918 	     chain = tcf_get_next_chain(block, chain)) {
1919 		struct tcf_proto *tp;
1920 
1921 		for (tp = tcf_get_next_proto(chain, NULL, true);
1922 		     tp; tp = tcf_get_next_proto(chain, tp, true)) {
1923 			struct tcf_bind_args arg = {};
1924 
1925 			arg.w.fn = tcf_node_bind;
1926 			arg.classid = clid;
1927 			arg.cl = new_cl;
1928 			tp->ops->walk(tp, &arg.w, true);
1929 		}
1930 	}
1931 }
1932 
1933 #else
1934 
1935 static void tc_bind_tclass(struct Qdisc *q, u32 portid, u32 clid,
1936 			   unsigned long new_cl)
1937 {
1938 }
1939 
1940 #endif
1941 
1942 static int tc_ctl_tclass(struct sk_buff *skb, struct nlmsghdr *n,
1943 			 struct netlink_ext_ack *extack)
1944 {
1945 	struct net *net = sock_net(skb->sk);
1946 	struct tcmsg *tcm = nlmsg_data(n);
1947 	struct nlattr *tca[TCA_MAX + 1];
1948 	struct net_device *dev;
1949 	struct Qdisc *q = NULL;
1950 	const struct Qdisc_class_ops *cops;
1951 	unsigned long cl = 0;
1952 	unsigned long new_cl;
1953 	u32 portid;
1954 	u32 clid;
1955 	u32 qid;
1956 	int err;
1957 
1958 	if ((n->nlmsg_type != RTM_GETTCLASS) &&
1959 	    !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
1960 		return -EPERM;
1961 
1962 	err = nlmsg_parse(n, sizeof(*tcm), tca, TCA_MAX, rtm_tca_policy,
1963 			  extack);
1964 	if (err < 0)
1965 		return err;
1966 
1967 	dev = __dev_get_by_index(net, tcm->tcm_ifindex);
1968 	if (!dev)
1969 		return -ENODEV;
1970 
1971 	/*
1972 	   parent == TC_H_UNSPEC - unspecified parent.
1973 	   parent == TC_H_ROOT   - class is root, which has no parent.
1974 	   parent == X:0	 - parent is root class.
1975 	   parent == X:Y	 - parent is a node in hierarchy.
1976 	   parent == 0:Y	 - parent is X:Y, where X:0 is qdisc.
1977 
1978 	   handle == 0:0	 - generate handle from kernel pool.
1979 	   handle == 0:Y	 - class is X:Y, where X:0 is qdisc.
1980 	   handle == X:Y	 - clear.
1981 	   handle == X:0	 - root class.
1982 	 */
1983 
1984 	/* Step 1. Determine qdisc handle X:0 */
1985 
1986 	portid = tcm->tcm_parent;
1987 	clid = tcm->tcm_handle;
1988 	qid = TC_H_MAJ(clid);
1989 
1990 	if (portid != TC_H_ROOT) {
1991 		u32 qid1 = TC_H_MAJ(portid);
1992 
1993 		if (qid && qid1) {
1994 			/* If both majors are known, they must be identical. */
1995 			if (qid != qid1)
1996 				return -EINVAL;
1997 		} else if (qid1) {
1998 			qid = qid1;
1999 		} else if (qid == 0)
2000 			qid = dev->qdisc->handle;
2001 
2002 		/* Now qid is genuine qdisc handle consistent
2003 		 * both with parent and child.
2004 		 *
2005 		 * TC_H_MAJ(portid) still may be unspecified, complete it now.
2006 		 */
2007 		if (portid)
2008 			portid = TC_H_MAKE(qid, portid);
2009 	} else {
2010 		if (qid == 0)
2011 			qid = dev->qdisc->handle;
2012 	}
2013 
2014 	/* OK. Locate qdisc */
2015 	q = qdisc_lookup(dev, qid);
2016 	if (!q)
2017 		return -ENOENT;
2018 
2019 	/* An check that it supports classes */
2020 	cops = q->ops->cl_ops;
2021 	if (cops == NULL)
2022 		return -EINVAL;
2023 
2024 	/* Now try to get class */
2025 	if (clid == 0) {
2026 		if (portid == TC_H_ROOT)
2027 			clid = qid;
2028 	} else
2029 		clid = TC_H_MAKE(qid, clid);
2030 
2031 	if (clid)
2032 		cl = cops->find(q, clid);
2033 
2034 	if (cl == 0) {
2035 		err = -ENOENT;
2036 		if (n->nlmsg_type != RTM_NEWTCLASS ||
2037 		    !(n->nlmsg_flags & NLM_F_CREATE))
2038 			goto out;
2039 	} else {
2040 		switch (n->nlmsg_type) {
2041 		case RTM_NEWTCLASS:
2042 			err = -EEXIST;
2043 			if (n->nlmsg_flags & NLM_F_EXCL)
2044 				goto out;
2045 			break;
2046 		case RTM_DELTCLASS:
2047 			err = tclass_del_notify(net, cops, skb, n, q, cl);
2048 			/* Unbind the class with flilters with 0 */
2049 			tc_bind_tclass(q, portid, clid, 0);
2050 			goto out;
2051 		case RTM_GETTCLASS:
2052 			err = tclass_notify(net, skb, n, q, cl, RTM_NEWTCLASS);
2053 			goto out;
2054 		default:
2055 			err = -EINVAL;
2056 			goto out;
2057 		}
2058 	}
2059 
2060 	if (tca[TCA_INGRESS_BLOCK] || tca[TCA_EGRESS_BLOCK]) {
2061 		NL_SET_ERR_MSG(extack, "Shared blocks are not supported for classes");
2062 		return -EOPNOTSUPP;
2063 	}
2064 
2065 	new_cl = cl;
2066 	err = -EOPNOTSUPP;
2067 	if (cops->change)
2068 		err = cops->change(q, clid, portid, tca, &new_cl, extack);
2069 	if (err == 0) {
2070 		tclass_notify(net, skb, n, q, new_cl, RTM_NEWTCLASS);
2071 		/* We just create a new class, need to do reverse binding. */
2072 		if (cl != new_cl)
2073 			tc_bind_tclass(q, portid, clid, new_cl);
2074 	}
2075 out:
2076 	return err;
2077 }
2078 
2079 struct qdisc_dump_args {
2080 	struct qdisc_walker	w;
2081 	struct sk_buff		*skb;
2082 	struct netlink_callback	*cb;
2083 };
2084 
2085 static int qdisc_class_dump(struct Qdisc *q, unsigned long cl,
2086 			    struct qdisc_walker *arg)
2087 {
2088 	struct qdisc_dump_args *a = (struct qdisc_dump_args *)arg;
2089 
2090 	return tc_fill_tclass(a->skb, q, cl, NETLINK_CB(a->cb->skb).portid,
2091 			      a->cb->nlh->nlmsg_seq, NLM_F_MULTI,
2092 			      RTM_NEWTCLASS);
2093 }
2094 
2095 static int tc_dump_tclass_qdisc(struct Qdisc *q, struct sk_buff *skb,
2096 				struct tcmsg *tcm, struct netlink_callback *cb,
2097 				int *t_p, int s_t)
2098 {
2099 	struct qdisc_dump_args arg;
2100 
2101 	if (tc_qdisc_dump_ignore(q, false) ||
2102 	    *t_p < s_t || !q->ops->cl_ops ||
2103 	    (tcm->tcm_parent &&
2104 	     TC_H_MAJ(tcm->tcm_parent) != q->handle)) {
2105 		(*t_p)++;
2106 		return 0;
2107 	}
2108 	if (*t_p > s_t)
2109 		memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0]));
2110 	arg.w.fn = qdisc_class_dump;
2111 	arg.skb = skb;
2112 	arg.cb = cb;
2113 	arg.w.stop  = 0;
2114 	arg.w.skip = cb->args[1];
2115 	arg.w.count = 0;
2116 	q->ops->cl_ops->walk(q, &arg.w);
2117 	cb->args[1] = arg.w.count;
2118 	if (arg.w.stop)
2119 		return -1;
2120 	(*t_p)++;
2121 	return 0;
2122 }
2123 
2124 static int tc_dump_tclass_root(struct Qdisc *root, struct sk_buff *skb,
2125 			       struct tcmsg *tcm, struct netlink_callback *cb,
2126 			       int *t_p, int s_t)
2127 {
2128 	struct Qdisc *q;
2129 	int b;
2130 
2131 	if (!root)
2132 		return 0;
2133 
2134 	if (tc_dump_tclass_qdisc(root, skb, tcm, cb, t_p, s_t) < 0)
2135 		return -1;
2136 
2137 	if (!qdisc_dev(root))
2138 		return 0;
2139 
2140 	if (tcm->tcm_parent) {
2141 		q = qdisc_match_from_root(root, TC_H_MAJ(tcm->tcm_parent));
2142 		if (q && q != root &&
2143 		    tc_dump_tclass_qdisc(q, skb, tcm, cb, t_p, s_t) < 0)
2144 			return -1;
2145 		return 0;
2146 	}
2147 	hash_for_each(qdisc_dev(root)->qdisc_hash, b, q, hash) {
2148 		if (tc_dump_tclass_qdisc(q, skb, tcm, cb, t_p, s_t) < 0)
2149 			return -1;
2150 	}
2151 
2152 	return 0;
2153 }
2154 
2155 static int tc_dump_tclass(struct sk_buff *skb, struct netlink_callback *cb)
2156 {
2157 	struct tcmsg *tcm = nlmsg_data(cb->nlh);
2158 	struct net *net = sock_net(skb->sk);
2159 	struct netdev_queue *dev_queue;
2160 	struct net_device *dev;
2161 	int t, s_t;
2162 
2163 	if (nlmsg_len(cb->nlh) < sizeof(*tcm))
2164 		return 0;
2165 	dev = dev_get_by_index(net, tcm->tcm_ifindex);
2166 	if (!dev)
2167 		return 0;
2168 
2169 	s_t = cb->args[0];
2170 	t = 0;
2171 
2172 	if (tc_dump_tclass_root(dev->qdisc, skb, tcm, cb, &t, s_t) < 0)
2173 		goto done;
2174 
2175 	dev_queue = dev_ingress_queue(dev);
2176 	if (dev_queue &&
2177 	    tc_dump_tclass_root(dev_queue->qdisc_sleeping, skb, tcm, cb,
2178 				&t, s_t) < 0)
2179 		goto done;
2180 
2181 done:
2182 	cb->args[0] = t;
2183 
2184 	dev_put(dev);
2185 	return skb->len;
2186 }
2187 
2188 #ifdef CONFIG_PROC_FS
2189 static int psched_show(struct seq_file *seq, void *v)
2190 {
2191 	seq_printf(seq, "%08x %08x %08x %08x\n",
2192 		   (u32)NSEC_PER_USEC, (u32)PSCHED_TICKS2NS(1),
2193 		   1000000,
2194 		   (u32)NSEC_PER_SEC / hrtimer_resolution);
2195 
2196 	return 0;
2197 }
2198 
2199 static int __net_init psched_net_init(struct net *net)
2200 {
2201 	struct proc_dir_entry *e;
2202 
2203 	e = proc_create_single("psched", 0, net->proc_net, psched_show);
2204 	if (e == NULL)
2205 		return -ENOMEM;
2206 
2207 	return 0;
2208 }
2209 
2210 static void __net_exit psched_net_exit(struct net *net)
2211 {
2212 	remove_proc_entry("psched", net->proc_net);
2213 }
2214 #else
2215 static int __net_init psched_net_init(struct net *net)
2216 {
2217 	return 0;
2218 }
2219 
2220 static void __net_exit psched_net_exit(struct net *net)
2221 {
2222 }
2223 #endif
2224 
2225 static struct pernet_operations psched_net_ops = {
2226 	.init = psched_net_init,
2227 	.exit = psched_net_exit,
2228 };
2229 
2230 static int __init pktsched_init(void)
2231 {
2232 	int err;
2233 
2234 	err = register_pernet_subsys(&psched_net_ops);
2235 	if (err) {
2236 		pr_err("pktsched_init: "
2237 		       "cannot initialize per netns operations\n");
2238 		return err;
2239 	}
2240 
2241 	register_qdisc(&pfifo_fast_ops);
2242 	register_qdisc(&pfifo_qdisc_ops);
2243 	register_qdisc(&bfifo_qdisc_ops);
2244 	register_qdisc(&pfifo_head_drop_qdisc_ops);
2245 	register_qdisc(&mq_qdisc_ops);
2246 	register_qdisc(&noqueue_qdisc_ops);
2247 
2248 	rtnl_register(PF_UNSPEC, RTM_NEWQDISC, tc_modify_qdisc, NULL, 0);
2249 	rtnl_register(PF_UNSPEC, RTM_DELQDISC, tc_get_qdisc, NULL, 0);
2250 	rtnl_register(PF_UNSPEC, RTM_GETQDISC, tc_get_qdisc, tc_dump_qdisc,
2251 		      0);
2252 	rtnl_register(PF_UNSPEC, RTM_NEWTCLASS, tc_ctl_tclass, NULL, 0);
2253 	rtnl_register(PF_UNSPEC, RTM_DELTCLASS, tc_ctl_tclass, NULL, 0);
2254 	rtnl_register(PF_UNSPEC, RTM_GETTCLASS, tc_ctl_tclass, tc_dump_tclass,
2255 		      0);
2256 
2257 	return 0;
2258 }
2259 
2260 subsys_initcall(pktsched_init);
2261