xref: /openbmc/linux/net/sched/sch_api.c (revision b9df3997)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * net/sched/sch_api.c	Packet scheduler API.
4  *
5  * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
6  *
7  * Fixes:
8  *
9  * Rani Assaf <rani@magic.metawire.com> :980802: JIFFIES and CPU clock sources are repaired.
10  * Eduardo J. Blanco <ejbs@netlabs.com.uy> :990222: kmod support
11  * Jamal Hadi Salim <hadi@nortelnetworks.com>: 990601: ingress support
12  */
13 
14 #include <linux/module.h>
15 #include <linux/types.h>
16 #include <linux/kernel.h>
17 #include <linux/string.h>
18 #include <linux/errno.h>
19 #include <linux/skbuff.h>
20 #include <linux/init.h>
21 #include <linux/proc_fs.h>
22 #include <linux/seq_file.h>
23 #include <linux/kmod.h>
24 #include <linux/list.h>
25 #include <linux/hrtimer.h>
26 #include <linux/slab.h>
27 #include <linux/hashtable.h>
28 
29 #include <net/net_namespace.h>
30 #include <net/sock.h>
31 #include <net/netlink.h>
32 #include <net/pkt_sched.h>
33 #include <net/pkt_cls.h>
34 
35 /*
36 
37    Short review.
38    -------------
39 
40    This file consists of two interrelated parts:
41 
42    1. queueing disciplines manager frontend.
43    2. traffic classes manager frontend.
44 
45    Generally, queueing discipline ("qdisc") is a black box,
46    which is able to enqueue packets and to dequeue them (when
47    device is ready to send something) in order and at times
48    determined by algorithm hidden in it.
49 
50    qdisc's are divided to two categories:
51    - "queues", which have no internal structure visible from outside.
52    - "schedulers", which split all the packets to "traffic classes",
53      using "packet classifiers" (look at cls_api.c)
54 
55    In turn, classes may have child qdiscs (as rule, queues)
56    attached to them etc. etc. etc.
57 
58    The goal of the routines in this file is to translate
59    information supplied by user in the form of handles
60    to more intelligible for kernel form, to make some sanity
61    checks and part of work, which is common to all qdiscs
62    and to provide rtnetlink notifications.
63 
64    All real intelligent work is done inside qdisc modules.
65 
66 
67 
68    Every discipline has two major routines: enqueue and dequeue.
69 
70    ---dequeue
71 
72    dequeue usually returns a skb to send. It is allowed to return NULL,
73    but it does not mean that queue is empty, it just means that
74    discipline does not want to send anything this time.
75    Queue is really empty if q->q.qlen == 0.
76    For complicated disciplines with multiple queues q->q is not
77    real packet queue, but however q->q.qlen must be valid.
78 
79    ---enqueue
80 
81    enqueue returns 0, if packet was enqueued successfully.
82    If packet (this one or another one) was dropped, it returns
83    not zero error code.
84    NET_XMIT_DROP 	- this packet dropped
85      Expected action: do not backoff, but wait until queue will clear.
86    NET_XMIT_CN	 	- probably this packet enqueued, but another one dropped.
87      Expected action: backoff or ignore
88 
89    Auxiliary routines:
90 
91    ---peek
92 
93    like dequeue but without removing a packet from the queue
94 
95    ---reset
96 
97    returns qdisc to initial state: purge all buffers, clear all
98    timers, counters (except for statistics) etc.
99 
100    ---init
101 
102    initializes newly created qdisc.
103 
104    ---destroy
105 
106    destroys resources allocated by init and during lifetime of qdisc.
107 
108    ---change
109 
110    changes qdisc parameters.
111  */
112 
113 /* Protects list of registered TC modules. It is pure SMP lock. */
114 static DEFINE_RWLOCK(qdisc_mod_lock);
115 
116 
117 /************************************************
118  *	Queueing disciplines manipulation.	*
119  ************************************************/
120 
121 
122 /* The list of all installed queueing disciplines. */
123 
124 static struct Qdisc_ops *qdisc_base;
125 
126 /* Register/unregister queueing discipline */
127 
128 int register_qdisc(struct Qdisc_ops *qops)
129 {
130 	struct Qdisc_ops *q, **qp;
131 	int rc = -EEXIST;
132 
133 	write_lock(&qdisc_mod_lock);
134 	for (qp = &qdisc_base; (q = *qp) != NULL; qp = &q->next)
135 		if (!strcmp(qops->id, q->id))
136 			goto out;
137 
138 	if (qops->enqueue == NULL)
139 		qops->enqueue = noop_qdisc_ops.enqueue;
140 	if (qops->peek == NULL) {
141 		if (qops->dequeue == NULL)
142 			qops->peek = noop_qdisc_ops.peek;
143 		else
144 			goto out_einval;
145 	}
146 	if (qops->dequeue == NULL)
147 		qops->dequeue = noop_qdisc_ops.dequeue;
148 
149 	if (qops->cl_ops) {
150 		const struct Qdisc_class_ops *cops = qops->cl_ops;
151 
152 		if (!(cops->find && cops->walk && cops->leaf))
153 			goto out_einval;
154 
155 		if (cops->tcf_block && !(cops->bind_tcf && cops->unbind_tcf))
156 			goto out_einval;
157 	}
158 
159 	qops->next = NULL;
160 	*qp = qops;
161 	rc = 0;
162 out:
163 	write_unlock(&qdisc_mod_lock);
164 	return rc;
165 
166 out_einval:
167 	rc = -EINVAL;
168 	goto out;
169 }
170 EXPORT_SYMBOL(register_qdisc);
171 
172 int unregister_qdisc(struct Qdisc_ops *qops)
173 {
174 	struct Qdisc_ops *q, **qp;
175 	int err = -ENOENT;
176 
177 	write_lock(&qdisc_mod_lock);
178 	for (qp = &qdisc_base; (q = *qp) != NULL; qp = &q->next)
179 		if (q == qops)
180 			break;
181 	if (q) {
182 		*qp = q->next;
183 		q->next = NULL;
184 		err = 0;
185 	}
186 	write_unlock(&qdisc_mod_lock);
187 	return err;
188 }
189 EXPORT_SYMBOL(unregister_qdisc);
190 
191 /* Get default qdisc if not otherwise specified */
192 void qdisc_get_default(char *name, size_t len)
193 {
194 	read_lock(&qdisc_mod_lock);
195 	strlcpy(name, default_qdisc_ops->id, len);
196 	read_unlock(&qdisc_mod_lock);
197 }
198 
199 static struct Qdisc_ops *qdisc_lookup_default(const char *name)
200 {
201 	struct Qdisc_ops *q = NULL;
202 
203 	for (q = qdisc_base; q; q = q->next) {
204 		if (!strcmp(name, q->id)) {
205 			if (!try_module_get(q->owner))
206 				q = NULL;
207 			break;
208 		}
209 	}
210 
211 	return q;
212 }
213 
214 /* Set new default qdisc to use */
215 int qdisc_set_default(const char *name)
216 {
217 	const struct Qdisc_ops *ops;
218 
219 	if (!capable(CAP_NET_ADMIN))
220 		return -EPERM;
221 
222 	write_lock(&qdisc_mod_lock);
223 	ops = qdisc_lookup_default(name);
224 	if (!ops) {
225 		/* Not found, drop lock and try to load module */
226 		write_unlock(&qdisc_mod_lock);
227 		request_module("sch_%s", name);
228 		write_lock(&qdisc_mod_lock);
229 
230 		ops = qdisc_lookup_default(name);
231 	}
232 
233 	if (ops) {
234 		/* Set new default */
235 		module_put(default_qdisc_ops->owner);
236 		default_qdisc_ops = ops;
237 	}
238 	write_unlock(&qdisc_mod_lock);
239 
240 	return ops ? 0 : -ENOENT;
241 }
242 
243 #ifdef CONFIG_NET_SCH_DEFAULT
244 /* Set default value from kernel config */
245 static int __init sch_default_qdisc(void)
246 {
247 	return qdisc_set_default(CONFIG_DEFAULT_NET_SCH);
248 }
249 late_initcall(sch_default_qdisc);
250 #endif
251 
252 /* We know handle. Find qdisc among all qdisc's attached to device
253  * (root qdisc, all its children, children of children etc.)
254  * Note: caller either uses rtnl or rcu_read_lock()
255  */
256 
257 static struct Qdisc *qdisc_match_from_root(struct Qdisc *root, u32 handle)
258 {
259 	struct Qdisc *q;
260 
261 	if (!qdisc_dev(root))
262 		return (root->handle == handle ? root : NULL);
263 
264 	if (!(root->flags & TCQ_F_BUILTIN) &&
265 	    root->handle == handle)
266 		return root;
267 
268 	hash_for_each_possible_rcu(qdisc_dev(root)->qdisc_hash, q, hash, handle) {
269 		if (q->handle == handle)
270 			return q;
271 	}
272 	return NULL;
273 }
274 
275 void qdisc_hash_add(struct Qdisc *q, bool invisible)
276 {
277 	if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS)) {
278 		ASSERT_RTNL();
279 		hash_add_rcu(qdisc_dev(q)->qdisc_hash, &q->hash, q->handle);
280 		if (invisible)
281 			q->flags |= TCQ_F_INVISIBLE;
282 	}
283 }
284 EXPORT_SYMBOL(qdisc_hash_add);
285 
286 void qdisc_hash_del(struct Qdisc *q)
287 {
288 	if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS)) {
289 		ASSERT_RTNL();
290 		hash_del_rcu(&q->hash);
291 	}
292 }
293 EXPORT_SYMBOL(qdisc_hash_del);
294 
295 struct Qdisc *qdisc_lookup(struct net_device *dev, u32 handle)
296 {
297 	struct Qdisc *q;
298 
299 	if (!handle)
300 		return NULL;
301 	q = qdisc_match_from_root(dev->qdisc, handle);
302 	if (q)
303 		goto out;
304 
305 	if (dev_ingress_queue(dev))
306 		q = qdisc_match_from_root(
307 			dev_ingress_queue(dev)->qdisc_sleeping,
308 			handle);
309 out:
310 	return q;
311 }
312 
313 struct Qdisc *qdisc_lookup_rcu(struct net_device *dev, u32 handle)
314 {
315 	struct netdev_queue *nq;
316 	struct Qdisc *q;
317 
318 	if (!handle)
319 		return NULL;
320 	q = qdisc_match_from_root(dev->qdisc, handle);
321 	if (q)
322 		goto out;
323 
324 	nq = dev_ingress_queue_rcu(dev);
325 	if (nq)
326 		q = qdisc_match_from_root(nq->qdisc_sleeping, handle);
327 out:
328 	return q;
329 }
330 
331 static struct Qdisc *qdisc_leaf(struct Qdisc *p, u32 classid)
332 {
333 	unsigned long cl;
334 	const struct Qdisc_class_ops *cops = p->ops->cl_ops;
335 
336 	if (cops == NULL)
337 		return NULL;
338 	cl = cops->find(p, classid);
339 
340 	if (cl == 0)
341 		return NULL;
342 	return cops->leaf(p, cl);
343 }
344 
345 /* Find queueing discipline by name */
346 
347 static struct Qdisc_ops *qdisc_lookup_ops(struct nlattr *kind)
348 {
349 	struct Qdisc_ops *q = NULL;
350 
351 	if (kind) {
352 		read_lock(&qdisc_mod_lock);
353 		for (q = qdisc_base; q; q = q->next) {
354 			if (nla_strcmp(kind, q->id) == 0) {
355 				if (!try_module_get(q->owner))
356 					q = NULL;
357 				break;
358 			}
359 		}
360 		read_unlock(&qdisc_mod_lock);
361 	}
362 	return q;
363 }
364 
365 /* The linklayer setting were not transferred from iproute2, in older
366  * versions, and the rate tables lookup systems have been dropped in
367  * the kernel. To keep backward compatible with older iproute2 tc
368  * utils, we detect the linklayer setting by detecting if the rate
369  * table were modified.
370  *
371  * For linklayer ATM table entries, the rate table will be aligned to
372  * 48 bytes, thus some table entries will contain the same value.  The
373  * mpu (min packet unit) is also encoded into the old rate table, thus
374  * starting from the mpu, we find low and high table entries for
375  * mapping this cell.  If these entries contain the same value, when
376  * the rate tables have been modified for linklayer ATM.
377  *
378  * This is done by rounding mpu to the nearest 48 bytes cell/entry,
379  * and then roundup to the next cell, calc the table entry one below,
380  * and compare.
381  */
382 static __u8 __detect_linklayer(struct tc_ratespec *r, __u32 *rtab)
383 {
384 	int low       = roundup(r->mpu, 48);
385 	int high      = roundup(low+1, 48);
386 	int cell_low  = low >> r->cell_log;
387 	int cell_high = (high >> r->cell_log) - 1;
388 
389 	/* rtab is too inaccurate at rates > 100Mbit/s */
390 	if ((r->rate > (100000000/8)) || (rtab[0] == 0)) {
391 		pr_debug("TC linklayer: Giving up ATM detection\n");
392 		return TC_LINKLAYER_ETHERNET;
393 	}
394 
395 	if ((cell_high > cell_low) && (cell_high < 256)
396 	    && (rtab[cell_low] == rtab[cell_high])) {
397 		pr_debug("TC linklayer: Detected ATM, low(%d)=high(%d)=%u\n",
398 			 cell_low, cell_high, rtab[cell_high]);
399 		return TC_LINKLAYER_ATM;
400 	}
401 	return TC_LINKLAYER_ETHERNET;
402 }
403 
404 static struct qdisc_rate_table *qdisc_rtab_list;
405 
406 struct qdisc_rate_table *qdisc_get_rtab(struct tc_ratespec *r,
407 					struct nlattr *tab,
408 					struct netlink_ext_ack *extack)
409 {
410 	struct qdisc_rate_table *rtab;
411 
412 	if (tab == NULL || r->rate == 0 || r->cell_log == 0 ||
413 	    nla_len(tab) != TC_RTAB_SIZE) {
414 		NL_SET_ERR_MSG(extack, "Invalid rate table parameters for searching");
415 		return NULL;
416 	}
417 
418 	for (rtab = qdisc_rtab_list; rtab; rtab = rtab->next) {
419 		if (!memcmp(&rtab->rate, r, sizeof(struct tc_ratespec)) &&
420 		    !memcmp(&rtab->data, nla_data(tab), 1024)) {
421 			rtab->refcnt++;
422 			return rtab;
423 		}
424 	}
425 
426 	rtab = kmalloc(sizeof(*rtab), GFP_KERNEL);
427 	if (rtab) {
428 		rtab->rate = *r;
429 		rtab->refcnt = 1;
430 		memcpy(rtab->data, nla_data(tab), 1024);
431 		if (r->linklayer == TC_LINKLAYER_UNAWARE)
432 			r->linklayer = __detect_linklayer(r, rtab->data);
433 		rtab->next = qdisc_rtab_list;
434 		qdisc_rtab_list = rtab;
435 	} else {
436 		NL_SET_ERR_MSG(extack, "Failed to allocate new qdisc rate table");
437 	}
438 	return rtab;
439 }
440 EXPORT_SYMBOL(qdisc_get_rtab);
441 
442 void qdisc_put_rtab(struct qdisc_rate_table *tab)
443 {
444 	struct qdisc_rate_table *rtab, **rtabp;
445 
446 	if (!tab || --tab->refcnt)
447 		return;
448 
449 	for (rtabp = &qdisc_rtab_list;
450 	     (rtab = *rtabp) != NULL;
451 	     rtabp = &rtab->next) {
452 		if (rtab == tab) {
453 			*rtabp = rtab->next;
454 			kfree(rtab);
455 			return;
456 		}
457 	}
458 }
459 EXPORT_SYMBOL(qdisc_put_rtab);
460 
461 static LIST_HEAD(qdisc_stab_list);
462 
463 static const struct nla_policy stab_policy[TCA_STAB_MAX + 1] = {
464 	[TCA_STAB_BASE]	= { .len = sizeof(struct tc_sizespec) },
465 	[TCA_STAB_DATA] = { .type = NLA_BINARY },
466 };
467 
468 static struct qdisc_size_table *qdisc_get_stab(struct nlattr *opt,
469 					       struct netlink_ext_ack *extack)
470 {
471 	struct nlattr *tb[TCA_STAB_MAX + 1];
472 	struct qdisc_size_table *stab;
473 	struct tc_sizespec *s;
474 	unsigned int tsize = 0;
475 	u16 *tab = NULL;
476 	int err;
477 
478 	err = nla_parse_nested_deprecated(tb, TCA_STAB_MAX, opt, stab_policy,
479 					  extack);
480 	if (err < 0)
481 		return ERR_PTR(err);
482 	if (!tb[TCA_STAB_BASE]) {
483 		NL_SET_ERR_MSG(extack, "Size table base attribute is missing");
484 		return ERR_PTR(-EINVAL);
485 	}
486 
487 	s = nla_data(tb[TCA_STAB_BASE]);
488 
489 	if (s->tsize > 0) {
490 		if (!tb[TCA_STAB_DATA]) {
491 			NL_SET_ERR_MSG(extack, "Size table data attribute is missing");
492 			return ERR_PTR(-EINVAL);
493 		}
494 		tab = nla_data(tb[TCA_STAB_DATA]);
495 		tsize = nla_len(tb[TCA_STAB_DATA]) / sizeof(u16);
496 	}
497 
498 	if (tsize != s->tsize || (!tab && tsize > 0)) {
499 		NL_SET_ERR_MSG(extack, "Invalid size of size table");
500 		return ERR_PTR(-EINVAL);
501 	}
502 
503 	list_for_each_entry(stab, &qdisc_stab_list, list) {
504 		if (memcmp(&stab->szopts, s, sizeof(*s)))
505 			continue;
506 		if (tsize > 0 && memcmp(stab->data, tab, tsize * sizeof(u16)))
507 			continue;
508 		stab->refcnt++;
509 		return stab;
510 	}
511 
512 	stab = kmalloc(sizeof(*stab) + tsize * sizeof(u16), GFP_KERNEL);
513 	if (!stab)
514 		return ERR_PTR(-ENOMEM);
515 
516 	stab->refcnt = 1;
517 	stab->szopts = *s;
518 	if (tsize > 0)
519 		memcpy(stab->data, tab, tsize * sizeof(u16));
520 
521 	list_add_tail(&stab->list, &qdisc_stab_list);
522 
523 	return stab;
524 }
525 
526 void qdisc_put_stab(struct qdisc_size_table *tab)
527 {
528 	if (!tab)
529 		return;
530 
531 	if (--tab->refcnt == 0) {
532 		list_del(&tab->list);
533 		kfree_rcu(tab, rcu);
534 	}
535 }
536 EXPORT_SYMBOL(qdisc_put_stab);
537 
538 static int qdisc_dump_stab(struct sk_buff *skb, struct qdisc_size_table *stab)
539 {
540 	struct nlattr *nest;
541 
542 	nest = nla_nest_start_noflag(skb, TCA_STAB);
543 	if (nest == NULL)
544 		goto nla_put_failure;
545 	if (nla_put(skb, TCA_STAB_BASE, sizeof(stab->szopts), &stab->szopts))
546 		goto nla_put_failure;
547 	nla_nest_end(skb, nest);
548 
549 	return skb->len;
550 
551 nla_put_failure:
552 	return -1;
553 }
554 
555 void __qdisc_calculate_pkt_len(struct sk_buff *skb,
556 			       const struct qdisc_size_table *stab)
557 {
558 	int pkt_len, slot;
559 
560 	pkt_len = skb->len + stab->szopts.overhead;
561 	if (unlikely(!stab->szopts.tsize))
562 		goto out;
563 
564 	slot = pkt_len + stab->szopts.cell_align;
565 	if (unlikely(slot < 0))
566 		slot = 0;
567 
568 	slot >>= stab->szopts.cell_log;
569 	if (likely(slot < stab->szopts.tsize))
570 		pkt_len = stab->data[slot];
571 	else
572 		pkt_len = stab->data[stab->szopts.tsize - 1] *
573 				(slot / stab->szopts.tsize) +
574 				stab->data[slot % stab->szopts.tsize];
575 
576 	pkt_len <<= stab->szopts.size_log;
577 out:
578 	if (unlikely(pkt_len < 1))
579 		pkt_len = 1;
580 	qdisc_skb_cb(skb)->pkt_len = pkt_len;
581 }
582 EXPORT_SYMBOL(__qdisc_calculate_pkt_len);
583 
584 void qdisc_warn_nonwc(const char *txt, struct Qdisc *qdisc)
585 {
586 	if (!(qdisc->flags & TCQ_F_WARN_NONWC)) {
587 		pr_warn("%s: %s qdisc %X: is non-work-conserving?\n",
588 			txt, qdisc->ops->id, qdisc->handle >> 16);
589 		qdisc->flags |= TCQ_F_WARN_NONWC;
590 	}
591 }
592 EXPORT_SYMBOL(qdisc_warn_nonwc);
593 
594 static enum hrtimer_restart qdisc_watchdog(struct hrtimer *timer)
595 {
596 	struct qdisc_watchdog *wd = container_of(timer, struct qdisc_watchdog,
597 						 timer);
598 
599 	rcu_read_lock();
600 	__netif_schedule(qdisc_root(wd->qdisc));
601 	rcu_read_unlock();
602 
603 	return HRTIMER_NORESTART;
604 }
605 
606 void qdisc_watchdog_init_clockid(struct qdisc_watchdog *wd, struct Qdisc *qdisc,
607 				 clockid_t clockid)
608 {
609 	hrtimer_init(&wd->timer, clockid, HRTIMER_MODE_ABS_PINNED);
610 	wd->timer.function = qdisc_watchdog;
611 	wd->qdisc = qdisc;
612 }
613 EXPORT_SYMBOL(qdisc_watchdog_init_clockid);
614 
615 void qdisc_watchdog_init(struct qdisc_watchdog *wd, struct Qdisc *qdisc)
616 {
617 	qdisc_watchdog_init_clockid(wd, qdisc, CLOCK_MONOTONIC);
618 }
619 EXPORT_SYMBOL(qdisc_watchdog_init);
620 
621 void qdisc_watchdog_schedule_ns(struct qdisc_watchdog *wd, u64 expires)
622 {
623 	if (test_bit(__QDISC_STATE_DEACTIVATED,
624 		     &qdisc_root_sleeping(wd->qdisc)->state))
625 		return;
626 
627 	if (wd->last_expires == expires)
628 		return;
629 
630 	wd->last_expires = expires;
631 	hrtimer_start(&wd->timer,
632 		      ns_to_ktime(expires),
633 		      HRTIMER_MODE_ABS_PINNED);
634 }
635 EXPORT_SYMBOL(qdisc_watchdog_schedule_ns);
636 
637 void qdisc_watchdog_cancel(struct qdisc_watchdog *wd)
638 {
639 	hrtimer_cancel(&wd->timer);
640 }
641 EXPORT_SYMBOL(qdisc_watchdog_cancel);
642 
643 static struct hlist_head *qdisc_class_hash_alloc(unsigned int n)
644 {
645 	struct hlist_head *h;
646 	unsigned int i;
647 
648 	h = kvmalloc_array(n, sizeof(struct hlist_head), GFP_KERNEL);
649 
650 	if (h != NULL) {
651 		for (i = 0; i < n; i++)
652 			INIT_HLIST_HEAD(&h[i]);
653 	}
654 	return h;
655 }
656 
657 void qdisc_class_hash_grow(struct Qdisc *sch, struct Qdisc_class_hash *clhash)
658 {
659 	struct Qdisc_class_common *cl;
660 	struct hlist_node *next;
661 	struct hlist_head *nhash, *ohash;
662 	unsigned int nsize, nmask, osize;
663 	unsigned int i, h;
664 
665 	/* Rehash when load factor exceeds 0.75 */
666 	if (clhash->hashelems * 4 <= clhash->hashsize * 3)
667 		return;
668 	nsize = clhash->hashsize * 2;
669 	nmask = nsize - 1;
670 	nhash = qdisc_class_hash_alloc(nsize);
671 	if (nhash == NULL)
672 		return;
673 
674 	ohash = clhash->hash;
675 	osize = clhash->hashsize;
676 
677 	sch_tree_lock(sch);
678 	for (i = 0; i < osize; i++) {
679 		hlist_for_each_entry_safe(cl, next, &ohash[i], hnode) {
680 			h = qdisc_class_hash(cl->classid, nmask);
681 			hlist_add_head(&cl->hnode, &nhash[h]);
682 		}
683 	}
684 	clhash->hash     = nhash;
685 	clhash->hashsize = nsize;
686 	clhash->hashmask = nmask;
687 	sch_tree_unlock(sch);
688 
689 	kvfree(ohash);
690 }
691 EXPORT_SYMBOL(qdisc_class_hash_grow);
692 
693 int qdisc_class_hash_init(struct Qdisc_class_hash *clhash)
694 {
695 	unsigned int size = 4;
696 
697 	clhash->hash = qdisc_class_hash_alloc(size);
698 	if (!clhash->hash)
699 		return -ENOMEM;
700 	clhash->hashsize  = size;
701 	clhash->hashmask  = size - 1;
702 	clhash->hashelems = 0;
703 	return 0;
704 }
705 EXPORT_SYMBOL(qdisc_class_hash_init);
706 
707 void qdisc_class_hash_destroy(struct Qdisc_class_hash *clhash)
708 {
709 	kvfree(clhash->hash);
710 }
711 EXPORT_SYMBOL(qdisc_class_hash_destroy);
712 
713 void qdisc_class_hash_insert(struct Qdisc_class_hash *clhash,
714 			     struct Qdisc_class_common *cl)
715 {
716 	unsigned int h;
717 
718 	INIT_HLIST_NODE(&cl->hnode);
719 	h = qdisc_class_hash(cl->classid, clhash->hashmask);
720 	hlist_add_head(&cl->hnode, &clhash->hash[h]);
721 	clhash->hashelems++;
722 }
723 EXPORT_SYMBOL(qdisc_class_hash_insert);
724 
725 void qdisc_class_hash_remove(struct Qdisc_class_hash *clhash,
726 			     struct Qdisc_class_common *cl)
727 {
728 	hlist_del(&cl->hnode);
729 	clhash->hashelems--;
730 }
731 EXPORT_SYMBOL(qdisc_class_hash_remove);
732 
733 /* Allocate an unique handle from space managed by kernel
734  * Possible range is [8000-FFFF]:0000 (0x8000 values)
735  */
736 static u32 qdisc_alloc_handle(struct net_device *dev)
737 {
738 	int i = 0x8000;
739 	static u32 autohandle = TC_H_MAKE(0x80000000U, 0);
740 
741 	do {
742 		autohandle += TC_H_MAKE(0x10000U, 0);
743 		if (autohandle == TC_H_MAKE(TC_H_ROOT, 0))
744 			autohandle = TC_H_MAKE(0x80000000U, 0);
745 		if (!qdisc_lookup(dev, autohandle))
746 			return autohandle;
747 		cond_resched();
748 	} while	(--i > 0);
749 
750 	return 0;
751 }
752 
753 void qdisc_tree_reduce_backlog(struct Qdisc *sch, int n, int len)
754 {
755 	bool qdisc_is_offloaded = sch->flags & TCQ_F_OFFLOADED;
756 	const struct Qdisc_class_ops *cops;
757 	unsigned long cl;
758 	u32 parentid;
759 	bool notify;
760 	int drops;
761 
762 	if (n == 0 && len == 0)
763 		return;
764 	drops = max_t(int, n, 0);
765 	rcu_read_lock();
766 	while ((parentid = sch->parent)) {
767 		if (TC_H_MAJ(parentid) == TC_H_MAJ(TC_H_INGRESS))
768 			break;
769 
770 		if (sch->flags & TCQ_F_NOPARENT)
771 			break;
772 		/* Notify parent qdisc only if child qdisc becomes empty.
773 		 *
774 		 * If child was empty even before update then backlog
775 		 * counter is screwed and we skip notification because
776 		 * parent class is already passive.
777 		 *
778 		 * If the original child was offloaded then it is allowed
779 		 * to be seem as empty, so the parent is notified anyway.
780 		 */
781 		notify = !sch->q.qlen && !WARN_ON_ONCE(!n &&
782 						       !qdisc_is_offloaded);
783 		/* TODO: perform the search on a per txq basis */
784 		sch = qdisc_lookup(qdisc_dev(sch), TC_H_MAJ(parentid));
785 		if (sch == NULL) {
786 			WARN_ON_ONCE(parentid != TC_H_ROOT);
787 			break;
788 		}
789 		cops = sch->ops->cl_ops;
790 		if (notify && cops->qlen_notify) {
791 			cl = cops->find(sch, parentid);
792 			cops->qlen_notify(sch, cl);
793 		}
794 		sch->q.qlen -= n;
795 		sch->qstats.backlog -= len;
796 		__qdisc_qstats_drop(sch, drops);
797 	}
798 	rcu_read_unlock();
799 }
800 EXPORT_SYMBOL(qdisc_tree_reduce_backlog);
801 
802 int qdisc_offload_dump_helper(struct Qdisc *sch, enum tc_setup_type type,
803 			      void *type_data)
804 {
805 	struct net_device *dev = qdisc_dev(sch);
806 	int err;
807 
808 	sch->flags &= ~TCQ_F_OFFLOADED;
809 	if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
810 		return 0;
811 
812 	err = dev->netdev_ops->ndo_setup_tc(dev, type, type_data);
813 	if (err == -EOPNOTSUPP)
814 		return 0;
815 
816 	if (!err)
817 		sch->flags |= TCQ_F_OFFLOADED;
818 
819 	return err;
820 }
821 EXPORT_SYMBOL(qdisc_offload_dump_helper);
822 
823 void qdisc_offload_graft_helper(struct net_device *dev, struct Qdisc *sch,
824 				struct Qdisc *new, struct Qdisc *old,
825 				enum tc_setup_type type, void *type_data,
826 				struct netlink_ext_ack *extack)
827 {
828 	bool any_qdisc_is_offloaded;
829 	int err;
830 
831 	if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
832 		return;
833 
834 	err = dev->netdev_ops->ndo_setup_tc(dev, type, type_data);
835 
836 	/* Don't report error if the graft is part of destroy operation. */
837 	if (!err || !new || new == &noop_qdisc)
838 		return;
839 
840 	/* Don't report error if the parent, the old child and the new
841 	 * one are not offloaded.
842 	 */
843 	any_qdisc_is_offloaded = new->flags & TCQ_F_OFFLOADED;
844 	any_qdisc_is_offloaded |= sch && sch->flags & TCQ_F_OFFLOADED;
845 	any_qdisc_is_offloaded |= old && old->flags & TCQ_F_OFFLOADED;
846 
847 	if (any_qdisc_is_offloaded)
848 		NL_SET_ERR_MSG(extack, "Offloading graft operation failed.");
849 }
850 EXPORT_SYMBOL(qdisc_offload_graft_helper);
851 
852 static void qdisc_offload_graft_root(struct net_device *dev,
853 				     struct Qdisc *new, struct Qdisc *old,
854 				     struct netlink_ext_ack *extack)
855 {
856 	struct tc_root_qopt_offload graft_offload = {
857 		.command	= TC_ROOT_GRAFT,
858 		.handle		= new ? new->handle : 0,
859 		.ingress	= (new && new->flags & TCQ_F_INGRESS) ||
860 				  (old && old->flags & TCQ_F_INGRESS),
861 	};
862 
863 	qdisc_offload_graft_helper(dev, NULL, new, old,
864 				   TC_SETUP_ROOT_QDISC, &graft_offload, extack);
865 }
866 
867 static int tc_fill_qdisc(struct sk_buff *skb, struct Qdisc *q, u32 clid,
868 			 u32 portid, u32 seq, u16 flags, int event)
869 {
870 	struct gnet_stats_basic_cpu __percpu *cpu_bstats = NULL;
871 	struct gnet_stats_queue __percpu *cpu_qstats = NULL;
872 	struct tcmsg *tcm;
873 	struct nlmsghdr  *nlh;
874 	unsigned char *b = skb_tail_pointer(skb);
875 	struct gnet_dump d;
876 	struct qdisc_size_table *stab;
877 	u32 block_index;
878 	__u32 qlen;
879 
880 	cond_resched();
881 	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*tcm), flags);
882 	if (!nlh)
883 		goto out_nlmsg_trim;
884 	tcm = nlmsg_data(nlh);
885 	tcm->tcm_family = AF_UNSPEC;
886 	tcm->tcm__pad1 = 0;
887 	tcm->tcm__pad2 = 0;
888 	tcm->tcm_ifindex = qdisc_dev(q)->ifindex;
889 	tcm->tcm_parent = clid;
890 	tcm->tcm_handle = q->handle;
891 	tcm->tcm_info = refcount_read(&q->refcnt);
892 	if (nla_put_string(skb, TCA_KIND, q->ops->id))
893 		goto nla_put_failure;
894 	if (q->ops->ingress_block_get) {
895 		block_index = q->ops->ingress_block_get(q);
896 		if (block_index &&
897 		    nla_put_u32(skb, TCA_INGRESS_BLOCK, block_index))
898 			goto nla_put_failure;
899 	}
900 	if (q->ops->egress_block_get) {
901 		block_index = q->ops->egress_block_get(q);
902 		if (block_index &&
903 		    nla_put_u32(skb, TCA_EGRESS_BLOCK, block_index))
904 			goto nla_put_failure;
905 	}
906 	if (q->ops->dump && q->ops->dump(q, skb) < 0)
907 		goto nla_put_failure;
908 	if (nla_put_u8(skb, TCA_HW_OFFLOAD, !!(q->flags & TCQ_F_OFFLOADED)))
909 		goto nla_put_failure;
910 	qlen = qdisc_qlen_sum(q);
911 
912 	stab = rtnl_dereference(q->stab);
913 	if (stab && qdisc_dump_stab(skb, stab) < 0)
914 		goto nla_put_failure;
915 
916 	if (gnet_stats_start_copy_compat(skb, TCA_STATS2, TCA_STATS, TCA_XSTATS,
917 					 NULL, &d, TCA_PAD) < 0)
918 		goto nla_put_failure;
919 
920 	if (q->ops->dump_stats && q->ops->dump_stats(q, &d) < 0)
921 		goto nla_put_failure;
922 
923 	if (qdisc_is_percpu_stats(q)) {
924 		cpu_bstats = q->cpu_bstats;
925 		cpu_qstats = q->cpu_qstats;
926 	}
927 
928 	if (gnet_stats_copy_basic(qdisc_root_sleeping_running(q),
929 				  &d, cpu_bstats, &q->bstats) < 0 ||
930 	    gnet_stats_copy_rate_est(&d, &q->rate_est) < 0 ||
931 	    gnet_stats_copy_queue(&d, cpu_qstats, &q->qstats, qlen) < 0)
932 		goto nla_put_failure;
933 
934 	if (gnet_stats_finish_copy(&d) < 0)
935 		goto nla_put_failure;
936 
937 	nlh->nlmsg_len = skb_tail_pointer(skb) - b;
938 	return skb->len;
939 
940 out_nlmsg_trim:
941 nla_put_failure:
942 	nlmsg_trim(skb, b);
943 	return -1;
944 }
945 
946 static bool tc_qdisc_dump_ignore(struct Qdisc *q, bool dump_invisible)
947 {
948 	if (q->flags & TCQ_F_BUILTIN)
949 		return true;
950 	if ((q->flags & TCQ_F_INVISIBLE) && !dump_invisible)
951 		return true;
952 
953 	return false;
954 }
955 
956 static int qdisc_notify(struct net *net, struct sk_buff *oskb,
957 			struct nlmsghdr *n, u32 clid,
958 			struct Qdisc *old, struct Qdisc *new)
959 {
960 	struct sk_buff *skb;
961 	u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
962 
963 	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
964 	if (!skb)
965 		return -ENOBUFS;
966 
967 	if (old && !tc_qdisc_dump_ignore(old, false)) {
968 		if (tc_fill_qdisc(skb, old, clid, portid, n->nlmsg_seq,
969 				  0, RTM_DELQDISC) < 0)
970 			goto err_out;
971 	}
972 	if (new && !tc_qdisc_dump_ignore(new, false)) {
973 		if (tc_fill_qdisc(skb, new, clid, portid, n->nlmsg_seq,
974 				  old ? NLM_F_REPLACE : 0, RTM_NEWQDISC) < 0)
975 			goto err_out;
976 	}
977 
978 	if (skb->len)
979 		return rtnetlink_send(skb, net, portid, RTNLGRP_TC,
980 				      n->nlmsg_flags & NLM_F_ECHO);
981 
982 err_out:
983 	kfree_skb(skb);
984 	return -EINVAL;
985 }
986 
987 static void notify_and_destroy(struct net *net, struct sk_buff *skb,
988 			       struct nlmsghdr *n, u32 clid,
989 			       struct Qdisc *old, struct Qdisc *new)
990 {
991 	if (new || old)
992 		qdisc_notify(net, skb, n, clid, old, new);
993 
994 	if (old)
995 		qdisc_put(old);
996 }
997 
998 static void qdisc_clear_nolock(struct Qdisc *sch)
999 {
1000 	sch->flags &= ~TCQ_F_NOLOCK;
1001 	if (!(sch->flags & TCQ_F_CPUSTATS))
1002 		return;
1003 
1004 	free_percpu(sch->cpu_bstats);
1005 	free_percpu(sch->cpu_qstats);
1006 	sch->cpu_bstats = NULL;
1007 	sch->cpu_qstats = NULL;
1008 	sch->flags &= ~TCQ_F_CPUSTATS;
1009 }
1010 
1011 /* Graft qdisc "new" to class "classid" of qdisc "parent" or
1012  * to device "dev".
1013  *
1014  * When appropriate send a netlink notification using 'skb'
1015  * and "n".
1016  *
1017  * On success, destroy old qdisc.
1018  */
1019 
1020 static int qdisc_graft(struct net_device *dev, struct Qdisc *parent,
1021 		       struct sk_buff *skb, struct nlmsghdr *n, u32 classid,
1022 		       struct Qdisc *new, struct Qdisc *old,
1023 		       struct netlink_ext_ack *extack)
1024 {
1025 	struct Qdisc *q = old;
1026 	struct net *net = dev_net(dev);
1027 
1028 	if (parent == NULL) {
1029 		unsigned int i, num_q, ingress;
1030 
1031 		ingress = 0;
1032 		num_q = dev->num_tx_queues;
1033 		if ((q && q->flags & TCQ_F_INGRESS) ||
1034 		    (new && new->flags & TCQ_F_INGRESS)) {
1035 			num_q = 1;
1036 			ingress = 1;
1037 			if (!dev_ingress_queue(dev)) {
1038 				NL_SET_ERR_MSG(extack, "Device does not have an ingress queue");
1039 				return -ENOENT;
1040 			}
1041 		}
1042 
1043 		if (dev->flags & IFF_UP)
1044 			dev_deactivate(dev);
1045 
1046 		qdisc_offload_graft_root(dev, new, old, extack);
1047 
1048 		if (new && new->ops->attach)
1049 			goto skip;
1050 
1051 		for (i = 0; i < num_q; i++) {
1052 			struct netdev_queue *dev_queue = dev_ingress_queue(dev);
1053 
1054 			if (!ingress)
1055 				dev_queue = netdev_get_tx_queue(dev, i);
1056 
1057 			old = dev_graft_qdisc(dev_queue, new);
1058 			if (new && i > 0)
1059 				qdisc_refcount_inc(new);
1060 
1061 			if (!ingress)
1062 				qdisc_put(old);
1063 		}
1064 
1065 skip:
1066 		if (!ingress) {
1067 			notify_and_destroy(net, skb, n, classid,
1068 					   dev->qdisc, new);
1069 			if (new && !new->ops->attach)
1070 				qdisc_refcount_inc(new);
1071 			dev->qdisc = new ? : &noop_qdisc;
1072 
1073 			if (new && new->ops->attach)
1074 				new->ops->attach(new);
1075 		} else {
1076 			notify_and_destroy(net, skb, n, classid, old, new);
1077 		}
1078 
1079 		if (dev->flags & IFF_UP)
1080 			dev_activate(dev);
1081 	} else {
1082 		const struct Qdisc_class_ops *cops = parent->ops->cl_ops;
1083 		unsigned long cl;
1084 		int err;
1085 
1086 		/* Only support running class lockless if parent is lockless */
1087 		if (new && (new->flags & TCQ_F_NOLOCK) &&
1088 		    parent && !(parent->flags & TCQ_F_NOLOCK))
1089 			qdisc_clear_nolock(new);
1090 
1091 		if (!cops || !cops->graft)
1092 			return -EOPNOTSUPP;
1093 
1094 		cl = cops->find(parent, classid);
1095 		if (!cl) {
1096 			NL_SET_ERR_MSG(extack, "Specified class not found");
1097 			return -ENOENT;
1098 		}
1099 
1100 		err = cops->graft(parent, cl, new, &old, extack);
1101 		if (err)
1102 			return err;
1103 		notify_and_destroy(net, skb, n, classid, old, new);
1104 	}
1105 	return 0;
1106 }
1107 
1108 static int qdisc_block_indexes_set(struct Qdisc *sch, struct nlattr **tca,
1109 				   struct netlink_ext_ack *extack)
1110 {
1111 	u32 block_index;
1112 
1113 	if (tca[TCA_INGRESS_BLOCK]) {
1114 		block_index = nla_get_u32(tca[TCA_INGRESS_BLOCK]);
1115 
1116 		if (!block_index) {
1117 			NL_SET_ERR_MSG(extack, "Ingress block index cannot be 0");
1118 			return -EINVAL;
1119 		}
1120 		if (!sch->ops->ingress_block_set) {
1121 			NL_SET_ERR_MSG(extack, "Ingress block sharing is not supported");
1122 			return -EOPNOTSUPP;
1123 		}
1124 		sch->ops->ingress_block_set(sch, block_index);
1125 	}
1126 	if (tca[TCA_EGRESS_BLOCK]) {
1127 		block_index = nla_get_u32(tca[TCA_EGRESS_BLOCK]);
1128 
1129 		if (!block_index) {
1130 			NL_SET_ERR_MSG(extack, "Egress block index cannot be 0");
1131 			return -EINVAL;
1132 		}
1133 		if (!sch->ops->egress_block_set) {
1134 			NL_SET_ERR_MSG(extack, "Egress block sharing is not supported");
1135 			return -EOPNOTSUPP;
1136 		}
1137 		sch->ops->egress_block_set(sch, block_index);
1138 	}
1139 	return 0;
1140 }
1141 
1142 /*
1143    Allocate and initialize new qdisc.
1144 
1145    Parameters are passed via opt.
1146  */
1147 
1148 static struct Qdisc *qdisc_create(struct net_device *dev,
1149 				  struct netdev_queue *dev_queue,
1150 				  struct Qdisc *p, u32 parent, u32 handle,
1151 				  struct nlattr **tca, int *errp,
1152 				  struct netlink_ext_ack *extack)
1153 {
1154 	int err;
1155 	struct nlattr *kind = tca[TCA_KIND];
1156 	struct Qdisc *sch;
1157 	struct Qdisc_ops *ops;
1158 	struct qdisc_size_table *stab;
1159 
1160 	ops = qdisc_lookup_ops(kind);
1161 #ifdef CONFIG_MODULES
1162 	if (ops == NULL && kind != NULL) {
1163 		char name[IFNAMSIZ];
1164 		if (nla_strlcpy(name, kind, IFNAMSIZ) < IFNAMSIZ) {
1165 			/* We dropped the RTNL semaphore in order to
1166 			 * perform the module load.  So, even if we
1167 			 * succeeded in loading the module we have to
1168 			 * tell the caller to replay the request.  We
1169 			 * indicate this using -EAGAIN.
1170 			 * We replay the request because the device may
1171 			 * go away in the mean time.
1172 			 */
1173 			rtnl_unlock();
1174 			request_module("sch_%s", name);
1175 			rtnl_lock();
1176 			ops = qdisc_lookup_ops(kind);
1177 			if (ops != NULL) {
1178 				/* We will try again qdisc_lookup_ops,
1179 				 * so don't keep a reference.
1180 				 */
1181 				module_put(ops->owner);
1182 				err = -EAGAIN;
1183 				goto err_out;
1184 			}
1185 		}
1186 	}
1187 #endif
1188 
1189 	err = -ENOENT;
1190 	if (!ops) {
1191 		NL_SET_ERR_MSG(extack, "Specified qdisc not found");
1192 		goto err_out;
1193 	}
1194 
1195 	sch = qdisc_alloc(dev_queue, ops, extack);
1196 	if (IS_ERR(sch)) {
1197 		err = PTR_ERR(sch);
1198 		goto err_out2;
1199 	}
1200 
1201 	sch->parent = parent;
1202 
1203 	if (handle == TC_H_INGRESS) {
1204 		sch->flags |= TCQ_F_INGRESS;
1205 		handle = TC_H_MAKE(TC_H_INGRESS, 0);
1206 	} else {
1207 		if (handle == 0) {
1208 			handle = qdisc_alloc_handle(dev);
1209 			if (handle == 0) {
1210 				NL_SET_ERR_MSG(extack, "Maximum number of qdisc handles was exceeded");
1211 				err = -ENOSPC;
1212 				goto err_out3;
1213 			}
1214 		}
1215 		if (!netif_is_multiqueue(dev))
1216 			sch->flags |= TCQ_F_ONETXQUEUE;
1217 	}
1218 
1219 	sch->handle = handle;
1220 
1221 	/* This exist to keep backward compatible with a userspace
1222 	 * loophole, what allowed userspace to get IFF_NO_QUEUE
1223 	 * facility on older kernels by setting tx_queue_len=0 (prior
1224 	 * to qdisc init), and then forgot to reinit tx_queue_len
1225 	 * before again attaching a qdisc.
1226 	 */
1227 	if ((dev->priv_flags & IFF_NO_QUEUE) && (dev->tx_queue_len == 0)) {
1228 		dev->tx_queue_len = DEFAULT_TX_QUEUE_LEN;
1229 		netdev_info(dev, "Caught tx_queue_len zero misconfig\n");
1230 	}
1231 
1232 	err = qdisc_block_indexes_set(sch, tca, extack);
1233 	if (err)
1234 		goto err_out3;
1235 
1236 	if (ops->init) {
1237 		err = ops->init(sch, tca[TCA_OPTIONS], extack);
1238 		if (err != 0)
1239 			goto err_out5;
1240 	}
1241 
1242 	if (tca[TCA_STAB]) {
1243 		stab = qdisc_get_stab(tca[TCA_STAB], extack);
1244 		if (IS_ERR(stab)) {
1245 			err = PTR_ERR(stab);
1246 			goto err_out4;
1247 		}
1248 		rcu_assign_pointer(sch->stab, stab);
1249 	}
1250 	if (tca[TCA_RATE]) {
1251 		seqcount_t *running;
1252 
1253 		err = -EOPNOTSUPP;
1254 		if (sch->flags & TCQ_F_MQROOT) {
1255 			NL_SET_ERR_MSG(extack, "Cannot attach rate estimator to a multi-queue root qdisc");
1256 			goto err_out4;
1257 		}
1258 
1259 		if (sch->parent != TC_H_ROOT &&
1260 		    !(sch->flags & TCQ_F_INGRESS) &&
1261 		    (!p || !(p->flags & TCQ_F_MQROOT)))
1262 			running = qdisc_root_sleeping_running(sch);
1263 		else
1264 			running = &sch->running;
1265 
1266 		err = gen_new_estimator(&sch->bstats,
1267 					sch->cpu_bstats,
1268 					&sch->rate_est,
1269 					NULL,
1270 					running,
1271 					tca[TCA_RATE]);
1272 		if (err) {
1273 			NL_SET_ERR_MSG(extack, "Failed to generate new estimator");
1274 			goto err_out4;
1275 		}
1276 	}
1277 
1278 	qdisc_hash_add(sch, false);
1279 
1280 	return sch;
1281 
1282 err_out5:
1283 	/* ops->init() failed, we call ->destroy() like qdisc_create_dflt() */
1284 	if (ops->destroy)
1285 		ops->destroy(sch);
1286 err_out3:
1287 	dev_put(dev);
1288 	qdisc_free(sch);
1289 err_out2:
1290 	module_put(ops->owner);
1291 err_out:
1292 	*errp = err;
1293 	return NULL;
1294 
1295 err_out4:
1296 	/*
1297 	 * Any broken qdiscs that would require a ops->reset() here?
1298 	 * The qdisc was never in action so it shouldn't be necessary.
1299 	 */
1300 	qdisc_put_stab(rtnl_dereference(sch->stab));
1301 	if (ops->destroy)
1302 		ops->destroy(sch);
1303 	goto err_out3;
1304 }
1305 
1306 static int qdisc_change(struct Qdisc *sch, struct nlattr **tca,
1307 			struct netlink_ext_ack *extack)
1308 {
1309 	struct qdisc_size_table *ostab, *stab = NULL;
1310 	int err = 0;
1311 
1312 	if (tca[TCA_OPTIONS]) {
1313 		if (!sch->ops->change) {
1314 			NL_SET_ERR_MSG(extack, "Change operation not supported by specified qdisc");
1315 			return -EINVAL;
1316 		}
1317 		if (tca[TCA_INGRESS_BLOCK] || tca[TCA_EGRESS_BLOCK]) {
1318 			NL_SET_ERR_MSG(extack, "Change of blocks is not supported");
1319 			return -EOPNOTSUPP;
1320 		}
1321 		err = sch->ops->change(sch, tca[TCA_OPTIONS], extack);
1322 		if (err)
1323 			return err;
1324 	}
1325 
1326 	if (tca[TCA_STAB]) {
1327 		stab = qdisc_get_stab(tca[TCA_STAB], extack);
1328 		if (IS_ERR(stab))
1329 			return PTR_ERR(stab);
1330 	}
1331 
1332 	ostab = rtnl_dereference(sch->stab);
1333 	rcu_assign_pointer(sch->stab, stab);
1334 	qdisc_put_stab(ostab);
1335 
1336 	if (tca[TCA_RATE]) {
1337 		/* NB: ignores errors from replace_estimator
1338 		   because change can't be undone. */
1339 		if (sch->flags & TCQ_F_MQROOT)
1340 			goto out;
1341 		gen_replace_estimator(&sch->bstats,
1342 				      sch->cpu_bstats,
1343 				      &sch->rate_est,
1344 				      NULL,
1345 				      qdisc_root_sleeping_running(sch),
1346 				      tca[TCA_RATE]);
1347 	}
1348 out:
1349 	return 0;
1350 }
1351 
1352 struct check_loop_arg {
1353 	struct qdisc_walker	w;
1354 	struct Qdisc		*p;
1355 	int			depth;
1356 };
1357 
1358 static int check_loop_fn(struct Qdisc *q, unsigned long cl,
1359 			 struct qdisc_walker *w);
1360 
1361 static int check_loop(struct Qdisc *q, struct Qdisc *p, int depth)
1362 {
1363 	struct check_loop_arg	arg;
1364 
1365 	if (q->ops->cl_ops == NULL)
1366 		return 0;
1367 
1368 	arg.w.stop = arg.w.skip = arg.w.count = 0;
1369 	arg.w.fn = check_loop_fn;
1370 	arg.depth = depth;
1371 	arg.p = p;
1372 	q->ops->cl_ops->walk(q, &arg.w);
1373 	return arg.w.stop ? -ELOOP : 0;
1374 }
1375 
1376 static int
1377 check_loop_fn(struct Qdisc *q, unsigned long cl, struct qdisc_walker *w)
1378 {
1379 	struct Qdisc *leaf;
1380 	const struct Qdisc_class_ops *cops = q->ops->cl_ops;
1381 	struct check_loop_arg *arg = (struct check_loop_arg *)w;
1382 
1383 	leaf = cops->leaf(q, cl);
1384 	if (leaf) {
1385 		if (leaf == arg->p || arg->depth > 7)
1386 			return -ELOOP;
1387 		return check_loop(leaf, arg->p, arg->depth + 1);
1388 	}
1389 	return 0;
1390 }
1391 
1392 const struct nla_policy rtm_tca_policy[TCA_MAX + 1] = {
1393 	[TCA_KIND]		= { .type = NLA_NUL_STRING,
1394 				    .len = IFNAMSIZ - 1 },
1395 	[TCA_RATE]		= { .type = NLA_BINARY,
1396 				    .len = sizeof(struct tc_estimator) },
1397 	[TCA_STAB]		= { .type = NLA_NESTED },
1398 	[TCA_DUMP_INVISIBLE]	= { .type = NLA_FLAG },
1399 	[TCA_CHAIN]		= { .type = NLA_U32 },
1400 	[TCA_INGRESS_BLOCK]	= { .type = NLA_U32 },
1401 	[TCA_EGRESS_BLOCK]	= { .type = NLA_U32 },
1402 };
1403 
1404 /*
1405  * Delete/get qdisc.
1406  */
1407 
1408 static int tc_get_qdisc(struct sk_buff *skb, struct nlmsghdr *n,
1409 			struct netlink_ext_ack *extack)
1410 {
1411 	struct net *net = sock_net(skb->sk);
1412 	struct tcmsg *tcm = nlmsg_data(n);
1413 	struct nlattr *tca[TCA_MAX + 1];
1414 	struct net_device *dev;
1415 	u32 clid;
1416 	struct Qdisc *q = NULL;
1417 	struct Qdisc *p = NULL;
1418 	int err;
1419 
1420 	if ((n->nlmsg_type != RTM_GETQDISC) &&
1421 	    !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
1422 		return -EPERM;
1423 
1424 	err = nlmsg_parse_deprecated(n, sizeof(*tcm), tca, TCA_MAX,
1425 				     rtm_tca_policy, extack);
1426 	if (err < 0)
1427 		return err;
1428 
1429 	dev = __dev_get_by_index(net, tcm->tcm_ifindex);
1430 	if (!dev)
1431 		return -ENODEV;
1432 
1433 	clid = tcm->tcm_parent;
1434 	if (clid) {
1435 		if (clid != TC_H_ROOT) {
1436 			if (TC_H_MAJ(clid) != TC_H_MAJ(TC_H_INGRESS)) {
1437 				p = qdisc_lookup(dev, TC_H_MAJ(clid));
1438 				if (!p) {
1439 					NL_SET_ERR_MSG(extack, "Failed to find qdisc with specified classid");
1440 					return -ENOENT;
1441 				}
1442 				q = qdisc_leaf(p, clid);
1443 			} else if (dev_ingress_queue(dev)) {
1444 				q = dev_ingress_queue(dev)->qdisc_sleeping;
1445 			}
1446 		} else {
1447 			q = dev->qdisc;
1448 		}
1449 		if (!q) {
1450 			NL_SET_ERR_MSG(extack, "Cannot find specified qdisc on specified device");
1451 			return -ENOENT;
1452 		}
1453 
1454 		if (tcm->tcm_handle && q->handle != tcm->tcm_handle) {
1455 			NL_SET_ERR_MSG(extack, "Invalid handle");
1456 			return -EINVAL;
1457 		}
1458 	} else {
1459 		q = qdisc_lookup(dev, tcm->tcm_handle);
1460 		if (!q) {
1461 			NL_SET_ERR_MSG(extack, "Failed to find qdisc with specified handle");
1462 			return -ENOENT;
1463 		}
1464 	}
1465 
1466 	if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], q->ops->id)) {
1467 		NL_SET_ERR_MSG(extack, "Invalid qdisc name");
1468 		return -EINVAL;
1469 	}
1470 
1471 	if (n->nlmsg_type == RTM_DELQDISC) {
1472 		if (!clid) {
1473 			NL_SET_ERR_MSG(extack, "Classid cannot be zero");
1474 			return -EINVAL;
1475 		}
1476 		if (q->handle == 0) {
1477 			NL_SET_ERR_MSG(extack, "Cannot delete qdisc with handle of zero");
1478 			return -ENOENT;
1479 		}
1480 		err = qdisc_graft(dev, p, skb, n, clid, NULL, q, extack);
1481 		if (err != 0)
1482 			return err;
1483 	} else {
1484 		qdisc_notify(net, skb, n, clid, NULL, q);
1485 	}
1486 	return 0;
1487 }
1488 
1489 /*
1490  * Create/change qdisc.
1491  */
1492 
1493 static int tc_modify_qdisc(struct sk_buff *skb, struct nlmsghdr *n,
1494 			   struct netlink_ext_ack *extack)
1495 {
1496 	struct net *net = sock_net(skb->sk);
1497 	struct tcmsg *tcm;
1498 	struct nlattr *tca[TCA_MAX + 1];
1499 	struct net_device *dev;
1500 	u32 clid;
1501 	struct Qdisc *q, *p;
1502 	int err;
1503 
1504 	if (!netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
1505 		return -EPERM;
1506 
1507 replay:
1508 	/* Reinit, just in case something touches this. */
1509 	err = nlmsg_parse_deprecated(n, sizeof(*tcm), tca, TCA_MAX,
1510 				     rtm_tca_policy, extack);
1511 	if (err < 0)
1512 		return err;
1513 
1514 	tcm = nlmsg_data(n);
1515 	clid = tcm->tcm_parent;
1516 	q = p = NULL;
1517 
1518 	dev = __dev_get_by_index(net, tcm->tcm_ifindex);
1519 	if (!dev)
1520 		return -ENODEV;
1521 
1522 
1523 	if (clid) {
1524 		if (clid != TC_H_ROOT) {
1525 			if (clid != TC_H_INGRESS) {
1526 				p = qdisc_lookup(dev, TC_H_MAJ(clid));
1527 				if (!p) {
1528 					NL_SET_ERR_MSG(extack, "Failed to find specified qdisc");
1529 					return -ENOENT;
1530 				}
1531 				q = qdisc_leaf(p, clid);
1532 			} else if (dev_ingress_queue_create(dev)) {
1533 				q = dev_ingress_queue(dev)->qdisc_sleeping;
1534 			}
1535 		} else {
1536 			q = dev->qdisc;
1537 		}
1538 
1539 		/* It may be default qdisc, ignore it */
1540 		if (q && q->handle == 0)
1541 			q = NULL;
1542 
1543 		if (!q || !tcm->tcm_handle || q->handle != tcm->tcm_handle) {
1544 			if (tcm->tcm_handle) {
1545 				if (q && !(n->nlmsg_flags & NLM_F_REPLACE)) {
1546 					NL_SET_ERR_MSG(extack, "NLM_F_REPLACE needed to override");
1547 					return -EEXIST;
1548 				}
1549 				if (TC_H_MIN(tcm->tcm_handle)) {
1550 					NL_SET_ERR_MSG(extack, "Invalid minor handle");
1551 					return -EINVAL;
1552 				}
1553 				q = qdisc_lookup(dev, tcm->tcm_handle);
1554 				if (!q)
1555 					goto create_n_graft;
1556 				if (n->nlmsg_flags & NLM_F_EXCL) {
1557 					NL_SET_ERR_MSG(extack, "Exclusivity flag on, cannot override");
1558 					return -EEXIST;
1559 				}
1560 				if (tca[TCA_KIND] &&
1561 				    nla_strcmp(tca[TCA_KIND], q->ops->id)) {
1562 					NL_SET_ERR_MSG(extack, "Invalid qdisc name");
1563 					return -EINVAL;
1564 				}
1565 				if (q == p ||
1566 				    (p && check_loop(q, p, 0))) {
1567 					NL_SET_ERR_MSG(extack, "Qdisc parent/child loop detected");
1568 					return -ELOOP;
1569 				}
1570 				qdisc_refcount_inc(q);
1571 				goto graft;
1572 			} else {
1573 				if (!q)
1574 					goto create_n_graft;
1575 
1576 				/* This magic test requires explanation.
1577 				 *
1578 				 *   We know, that some child q is already
1579 				 *   attached to this parent and have choice:
1580 				 *   either to change it or to create/graft new one.
1581 				 *
1582 				 *   1. We are allowed to create/graft only
1583 				 *   if CREATE and REPLACE flags are set.
1584 				 *
1585 				 *   2. If EXCL is set, requestor wanted to say,
1586 				 *   that qdisc tcm_handle is not expected
1587 				 *   to exist, so that we choose create/graft too.
1588 				 *
1589 				 *   3. The last case is when no flags are set.
1590 				 *   Alas, it is sort of hole in API, we
1591 				 *   cannot decide what to do unambiguously.
1592 				 *   For now we select create/graft, if
1593 				 *   user gave KIND, which does not match existing.
1594 				 */
1595 				if ((n->nlmsg_flags & NLM_F_CREATE) &&
1596 				    (n->nlmsg_flags & NLM_F_REPLACE) &&
1597 				    ((n->nlmsg_flags & NLM_F_EXCL) ||
1598 				     (tca[TCA_KIND] &&
1599 				      nla_strcmp(tca[TCA_KIND], q->ops->id))))
1600 					goto create_n_graft;
1601 			}
1602 		}
1603 	} else {
1604 		if (!tcm->tcm_handle) {
1605 			NL_SET_ERR_MSG(extack, "Handle cannot be zero");
1606 			return -EINVAL;
1607 		}
1608 		q = qdisc_lookup(dev, tcm->tcm_handle);
1609 	}
1610 
1611 	/* Change qdisc parameters */
1612 	if (!q) {
1613 		NL_SET_ERR_MSG(extack, "Specified qdisc not found");
1614 		return -ENOENT;
1615 	}
1616 	if (n->nlmsg_flags & NLM_F_EXCL) {
1617 		NL_SET_ERR_MSG(extack, "Exclusivity flag on, cannot modify");
1618 		return -EEXIST;
1619 	}
1620 	if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], q->ops->id)) {
1621 		NL_SET_ERR_MSG(extack, "Invalid qdisc name");
1622 		return -EINVAL;
1623 	}
1624 	err = qdisc_change(q, tca, extack);
1625 	if (err == 0)
1626 		qdisc_notify(net, skb, n, clid, NULL, q);
1627 	return err;
1628 
1629 create_n_graft:
1630 	if (!(n->nlmsg_flags & NLM_F_CREATE)) {
1631 		NL_SET_ERR_MSG(extack, "Qdisc not found. To create specify NLM_F_CREATE flag");
1632 		return -ENOENT;
1633 	}
1634 	if (clid == TC_H_INGRESS) {
1635 		if (dev_ingress_queue(dev)) {
1636 			q = qdisc_create(dev, dev_ingress_queue(dev), p,
1637 					 tcm->tcm_parent, tcm->tcm_parent,
1638 					 tca, &err, extack);
1639 		} else {
1640 			NL_SET_ERR_MSG(extack, "Cannot find ingress queue for specified device");
1641 			err = -ENOENT;
1642 		}
1643 	} else {
1644 		struct netdev_queue *dev_queue;
1645 
1646 		if (p && p->ops->cl_ops && p->ops->cl_ops->select_queue)
1647 			dev_queue = p->ops->cl_ops->select_queue(p, tcm);
1648 		else if (p)
1649 			dev_queue = p->dev_queue;
1650 		else
1651 			dev_queue = netdev_get_tx_queue(dev, 0);
1652 
1653 		q = qdisc_create(dev, dev_queue, p,
1654 				 tcm->tcm_parent, tcm->tcm_handle,
1655 				 tca, &err, extack);
1656 	}
1657 	if (q == NULL) {
1658 		if (err == -EAGAIN)
1659 			goto replay;
1660 		return err;
1661 	}
1662 
1663 graft:
1664 	err = qdisc_graft(dev, p, skb, n, clid, q, NULL, extack);
1665 	if (err) {
1666 		if (q)
1667 			qdisc_put(q);
1668 		return err;
1669 	}
1670 
1671 	return 0;
1672 }
1673 
1674 static int tc_dump_qdisc_root(struct Qdisc *root, struct sk_buff *skb,
1675 			      struct netlink_callback *cb,
1676 			      int *q_idx_p, int s_q_idx, bool recur,
1677 			      bool dump_invisible)
1678 {
1679 	int ret = 0, q_idx = *q_idx_p;
1680 	struct Qdisc *q;
1681 	int b;
1682 
1683 	if (!root)
1684 		return 0;
1685 
1686 	q = root;
1687 	if (q_idx < s_q_idx) {
1688 		q_idx++;
1689 	} else {
1690 		if (!tc_qdisc_dump_ignore(q, dump_invisible) &&
1691 		    tc_fill_qdisc(skb, q, q->parent, NETLINK_CB(cb->skb).portid,
1692 				  cb->nlh->nlmsg_seq, NLM_F_MULTI,
1693 				  RTM_NEWQDISC) <= 0)
1694 			goto done;
1695 		q_idx++;
1696 	}
1697 
1698 	/* If dumping singletons, there is no qdisc_dev(root) and the singleton
1699 	 * itself has already been dumped.
1700 	 *
1701 	 * If we've already dumped the top-level (ingress) qdisc above and the global
1702 	 * qdisc hashtable, we don't want to hit it again
1703 	 */
1704 	if (!qdisc_dev(root) || !recur)
1705 		goto out;
1706 
1707 	hash_for_each(qdisc_dev(root)->qdisc_hash, b, q, hash) {
1708 		if (q_idx < s_q_idx) {
1709 			q_idx++;
1710 			continue;
1711 		}
1712 		if (!tc_qdisc_dump_ignore(q, dump_invisible) &&
1713 		    tc_fill_qdisc(skb, q, q->parent, NETLINK_CB(cb->skb).portid,
1714 				  cb->nlh->nlmsg_seq, NLM_F_MULTI,
1715 				  RTM_NEWQDISC) <= 0)
1716 			goto done;
1717 		q_idx++;
1718 	}
1719 
1720 out:
1721 	*q_idx_p = q_idx;
1722 	return ret;
1723 done:
1724 	ret = -1;
1725 	goto out;
1726 }
1727 
1728 static int tc_dump_qdisc(struct sk_buff *skb, struct netlink_callback *cb)
1729 {
1730 	struct net *net = sock_net(skb->sk);
1731 	int idx, q_idx;
1732 	int s_idx, s_q_idx;
1733 	struct net_device *dev;
1734 	const struct nlmsghdr *nlh = cb->nlh;
1735 	struct nlattr *tca[TCA_MAX + 1];
1736 	int err;
1737 
1738 	s_idx = cb->args[0];
1739 	s_q_idx = q_idx = cb->args[1];
1740 
1741 	idx = 0;
1742 	ASSERT_RTNL();
1743 
1744 	err = nlmsg_parse_deprecated(nlh, sizeof(struct tcmsg), tca, TCA_MAX,
1745 				     rtm_tca_policy, cb->extack);
1746 	if (err < 0)
1747 		return err;
1748 
1749 	for_each_netdev(net, dev) {
1750 		struct netdev_queue *dev_queue;
1751 
1752 		if (idx < s_idx)
1753 			goto cont;
1754 		if (idx > s_idx)
1755 			s_q_idx = 0;
1756 		q_idx = 0;
1757 
1758 		if (tc_dump_qdisc_root(dev->qdisc, skb, cb, &q_idx, s_q_idx,
1759 				       true, tca[TCA_DUMP_INVISIBLE]) < 0)
1760 			goto done;
1761 
1762 		dev_queue = dev_ingress_queue(dev);
1763 		if (dev_queue &&
1764 		    tc_dump_qdisc_root(dev_queue->qdisc_sleeping, skb, cb,
1765 				       &q_idx, s_q_idx, false,
1766 				       tca[TCA_DUMP_INVISIBLE]) < 0)
1767 			goto done;
1768 
1769 cont:
1770 		idx++;
1771 	}
1772 
1773 done:
1774 	cb->args[0] = idx;
1775 	cb->args[1] = q_idx;
1776 
1777 	return skb->len;
1778 }
1779 
1780 
1781 
1782 /************************************************
1783  *	Traffic classes manipulation.		*
1784  ************************************************/
1785 
1786 static int tc_fill_tclass(struct sk_buff *skb, struct Qdisc *q,
1787 			  unsigned long cl,
1788 			  u32 portid, u32 seq, u16 flags, int event)
1789 {
1790 	struct tcmsg *tcm;
1791 	struct nlmsghdr  *nlh;
1792 	unsigned char *b = skb_tail_pointer(skb);
1793 	struct gnet_dump d;
1794 	const struct Qdisc_class_ops *cl_ops = q->ops->cl_ops;
1795 
1796 	cond_resched();
1797 	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*tcm), flags);
1798 	if (!nlh)
1799 		goto out_nlmsg_trim;
1800 	tcm = nlmsg_data(nlh);
1801 	tcm->tcm_family = AF_UNSPEC;
1802 	tcm->tcm__pad1 = 0;
1803 	tcm->tcm__pad2 = 0;
1804 	tcm->tcm_ifindex = qdisc_dev(q)->ifindex;
1805 	tcm->tcm_parent = q->handle;
1806 	tcm->tcm_handle = q->handle;
1807 	tcm->tcm_info = 0;
1808 	if (nla_put_string(skb, TCA_KIND, q->ops->id))
1809 		goto nla_put_failure;
1810 	if (cl_ops->dump && cl_ops->dump(q, cl, skb, tcm) < 0)
1811 		goto nla_put_failure;
1812 
1813 	if (gnet_stats_start_copy_compat(skb, TCA_STATS2, TCA_STATS, TCA_XSTATS,
1814 					 NULL, &d, TCA_PAD) < 0)
1815 		goto nla_put_failure;
1816 
1817 	if (cl_ops->dump_stats && cl_ops->dump_stats(q, cl, &d) < 0)
1818 		goto nla_put_failure;
1819 
1820 	if (gnet_stats_finish_copy(&d) < 0)
1821 		goto nla_put_failure;
1822 
1823 	nlh->nlmsg_len = skb_tail_pointer(skb) - b;
1824 	return skb->len;
1825 
1826 out_nlmsg_trim:
1827 nla_put_failure:
1828 	nlmsg_trim(skb, b);
1829 	return -1;
1830 }
1831 
1832 static int tclass_notify(struct net *net, struct sk_buff *oskb,
1833 			 struct nlmsghdr *n, struct Qdisc *q,
1834 			 unsigned long cl, int event)
1835 {
1836 	struct sk_buff *skb;
1837 	u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
1838 	int err = 0;
1839 
1840 	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
1841 	if (!skb)
1842 		return -ENOBUFS;
1843 
1844 	if (tc_fill_tclass(skb, q, cl, portid, n->nlmsg_seq, 0, event) < 0) {
1845 		kfree_skb(skb);
1846 		return -EINVAL;
1847 	}
1848 
1849 	err = rtnetlink_send(skb, net, portid, RTNLGRP_TC,
1850 			     n->nlmsg_flags & NLM_F_ECHO);
1851 	if (err > 0)
1852 		err = 0;
1853 	return err;
1854 }
1855 
1856 static int tclass_del_notify(struct net *net,
1857 			     const struct Qdisc_class_ops *cops,
1858 			     struct sk_buff *oskb, struct nlmsghdr *n,
1859 			     struct Qdisc *q, unsigned long cl)
1860 {
1861 	u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
1862 	struct sk_buff *skb;
1863 	int err = 0;
1864 
1865 	if (!cops->delete)
1866 		return -EOPNOTSUPP;
1867 
1868 	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
1869 	if (!skb)
1870 		return -ENOBUFS;
1871 
1872 	if (tc_fill_tclass(skb, q, cl, portid, n->nlmsg_seq, 0,
1873 			   RTM_DELTCLASS) < 0) {
1874 		kfree_skb(skb);
1875 		return -EINVAL;
1876 	}
1877 
1878 	err = cops->delete(q, cl);
1879 	if (err) {
1880 		kfree_skb(skb);
1881 		return err;
1882 	}
1883 
1884 	err = rtnetlink_send(skb, net, portid, RTNLGRP_TC,
1885 			     n->nlmsg_flags & NLM_F_ECHO);
1886 	if (err > 0)
1887 		err = 0;
1888 	return err;
1889 }
1890 
1891 #ifdef CONFIG_NET_CLS
1892 
1893 struct tcf_bind_args {
1894 	struct tcf_walker w;
1895 	u32 classid;
1896 	unsigned long cl;
1897 };
1898 
1899 static int tcf_node_bind(struct tcf_proto *tp, void *n, struct tcf_walker *arg)
1900 {
1901 	struct tcf_bind_args *a = (void *)arg;
1902 
1903 	if (tp->ops->bind_class) {
1904 		struct Qdisc *q = tcf_block_q(tp->chain->block);
1905 
1906 		sch_tree_lock(q);
1907 		tp->ops->bind_class(n, a->classid, a->cl);
1908 		sch_tree_unlock(q);
1909 	}
1910 	return 0;
1911 }
1912 
1913 static void tc_bind_tclass(struct Qdisc *q, u32 portid, u32 clid,
1914 			   unsigned long new_cl)
1915 {
1916 	const struct Qdisc_class_ops *cops = q->ops->cl_ops;
1917 	struct tcf_block *block;
1918 	struct tcf_chain *chain;
1919 	unsigned long cl;
1920 
1921 	cl = cops->find(q, portid);
1922 	if (!cl)
1923 		return;
1924 	if (!cops->tcf_block)
1925 		return;
1926 	block = cops->tcf_block(q, cl, NULL);
1927 	if (!block)
1928 		return;
1929 	for (chain = tcf_get_next_chain(block, NULL);
1930 	     chain;
1931 	     chain = tcf_get_next_chain(block, chain)) {
1932 		struct tcf_proto *tp;
1933 
1934 		for (tp = tcf_get_next_proto(chain, NULL, true);
1935 		     tp; tp = tcf_get_next_proto(chain, tp, true)) {
1936 			struct tcf_bind_args arg = {};
1937 
1938 			arg.w.fn = tcf_node_bind;
1939 			arg.classid = clid;
1940 			arg.cl = new_cl;
1941 			tp->ops->walk(tp, &arg.w, true);
1942 		}
1943 	}
1944 }
1945 
1946 #else
1947 
1948 static void tc_bind_tclass(struct Qdisc *q, u32 portid, u32 clid,
1949 			   unsigned long new_cl)
1950 {
1951 }
1952 
1953 #endif
1954 
1955 static int tc_ctl_tclass(struct sk_buff *skb, struct nlmsghdr *n,
1956 			 struct netlink_ext_ack *extack)
1957 {
1958 	struct net *net = sock_net(skb->sk);
1959 	struct tcmsg *tcm = nlmsg_data(n);
1960 	struct nlattr *tca[TCA_MAX + 1];
1961 	struct net_device *dev;
1962 	struct Qdisc *q = NULL;
1963 	const struct Qdisc_class_ops *cops;
1964 	unsigned long cl = 0;
1965 	unsigned long new_cl;
1966 	u32 portid;
1967 	u32 clid;
1968 	u32 qid;
1969 	int err;
1970 
1971 	if ((n->nlmsg_type != RTM_GETTCLASS) &&
1972 	    !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
1973 		return -EPERM;
1974 
1975 	err = nlmsg_parse_deprecated(n, sizeof(*tcm), tca, TCA_MAX,
1976 				     rtm_tca_policy, extack);
1977 	if (err < 0)
1978 		return err;
1979 
1980 	dev = __dev_get_by_index(net, tcm->tcm_ifindex);
1981 	if (!dev)
1982 		return -ENODEV;
1983 
1984 	/*
1985 	   parent == TC_H_UNSPEC - unspecified parent.
1986 	   parent == TC_H_ROOT   - class is root, which has no parent.
1987 	   parent == X:0	 - parent is root class.
1988 	   parent == X:Y	 - parent is a node in hierarchy.
1989 	   parent == 0:Y	 - parent is X:Y, where X:0 is qdisc.
1990 
1991 	   handle == 0:0	 - generate handle from kernel pool.
1992 	   handle == 0:Y	 - class is X:Y, where X:0 is qdisc.
1993 	   handle == X:Y	 - clear.
1994 	   handle == X:0	 - root class.
1995 	 */
1996 
1997 	/* Step 1. Determine qdisc handle X:0 */
1998 
1999 	portid = tcm->tcm_parent;
2000 	clid = tcm->tcm_handle;
2001 	qid = TC_H_MAJ(clid);
2002 
2003 	if (portid != TC_H_ROOT) {
2004 		u32 qid1 = TC_H_MAJ(portid);
2005 
2006 		if (qid && qid1) {
2007 			/* If both majors are known, they must be identical. */
2008 			if (qid != qid1)
2009 				return -EINVAL;
2010 		} else if (qid1) {
2011 			qid = qid1;
2012 		} else if (qid == 0)
2013 			qid = dev->qdisc->handle;
2014 
2015 		/* Now qid is genuine qdisc handle consistent
2016 		 * both with parent and child.
2017 		 *
2018 		 * TC_H_MAJ(portid) still may be unspecified, complete it now.
2019 		 */
2020 		if (portid)
2021 			portid = TC_H_MAKE(qid, portid);
2022 	} else {
2023 		if (qid == 0)
2024 			qid = dev->qdisc->handle;
2025 	}
2026 
2027 	/* OK. Locate qdisc */
2028 	q = qdisc_lookup(dev, qid);
2029 	if (!q)
2030 		return -ENOENT;
2031 
2032 	/* An check that it supports classes */
2033 	cops = q->ops->cl_ops;
2034 	if (cops == NULL)
2035 		return -EINVAL;
2036 
2037 	/* Now try to get class */
2038 	if (clid == 0) {
2039 		if (portid == TC_H_ROOT)
2040 			clid = qid;
2041 	} else
2042 		clid = TC_H_MAKE(qid, clid);
2043 
2044 	if (clid)
2045 		cl = cops->find(q, clid);
2046 
2047 	if (cl == 0) {
2048 		err = -ENOENT;
2049 		if (n->nlmsg_type != RTM_NEWTCLASS ||
2050 		    !(n->nlmsg_flags & NLM_F_CREATE))
2051 			goto out;
2052 	} else {
2053 		switch (n->nlmsg_type) {
2054 		case RTM_NEWTCLASS:
2055 			err = -EEXIST;
2056 			if (n->nlmsg_flags & NLM_F_EXCL)
2057 				goto out;
2058 			break;
2059 		case RTM_DELTCLASS:
2060 			err = tclass_del_notify(net, cops, skb, n, q, cl);
2061 			/* Unbind the class with flilters with 0 */
2062 			tc_bind_tclass(q, portid, clid, 0);
2063 			goto out;
2064 		case RTM_GETTCLASS:
2065 			err = tclass_notify(net, skb, n, q, cl, RTM_NEWTCLASS);
2066 			goto out;
2067 		default:
2068 			err = -EINVAL;
2069 			goto out;
2070 		}
2071 	}
2072 
2073 	if (tca[TCA_INGRESS_BLOCK] || tca[TCA_EGRESS_BLOCK]) {
2074 		NL_SET_ERR_MSG(extack, "Shared blocks are not supported for classes");
2075 		return -EOPNOTSUPP;
2076 	}
2077 
2078 	new_cl = cl;
2079 	err = -EOPNOTSUPP;
2080 	if (cops->change)
2081 		err = cops->change(q, clid, portid, tca, &new_cl, extack);
2082 	if (err == 0) {
2083 		tclass_notify(net, skb, n, q, new_cl, RTM_NEWTCLASS);
2084 		/* We just create a new class, need to do reverse binding. */
2085 		if (cl != new_cl)
2086 			tc_bind_tclass(q, portid, clid, new_cl);
2087 	}
2088 out:
2089 	return err;
2090 }
2091 
2092 struct qdisc_dump_args {
2093 	struct qdisc_walker	w;
2094 	struct sk_buff		*skb;
2095 	struct netlink_callback	*cb;
2096 };
2097 
2098 static int qdisc_class_dump(struct Qdisc *q, unsigned long cl,
2099 			    struct qdisc_walker *arg)
2100 {
2101 	struct qdisc_dump_args *a = (struct qdisc_dump_args *)arg;
2102 
2103 	return tc_fill_tclass(a->skb, q, cl, NETLINK_CB(a->cb->skb).portid,
2104 			      a->cb->nlh->nlmsg_seq, NLM_F_MULTI,
2105 			      RTM_NEWTCLASS);
2106 }
2107 
2108 static int tc_dump_tclass_qdisc(struct Qdisc *q, struct sk_buff *skb,
2109 				struct tcmsg *tcm, struct netlink_callback *cb,
2110 				int *t_p, int s_t)
2111 {
2112 	struct qdisc_dump_args arg;
2113 
2114 	if (tc_qdisc_dump_ignore(q, false) ||
2115 	    *t_p < s_t || !q->ops->cl_ops ||
2116 	    (tcm->tcm_parent &&
2117 	     TC_H_MAJ(tcm->tcm_parent) != q->handle)) {
2118 		(*t_p)++;
2119 		return 0;
2120 	}
2121 	if (*t_p > s_t)
2122 		memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0]));
2123 	arg.w.fn = qdisc_class_dump;
2124 	arg.skb = skb;
2125 	arg.cb = cb;
2126 	arg.w.stop  = 0;
2127 	arg.w.skip = cb->args[1];
2128 	arg.w.count = 0;
2129 	q->ops->cl_ops->walk(q, &arg.w);
2130 	cb->args[1] = arg.w.count;
2131 	if (arg.w.stop)
2132 		return -1;
2133 	(*t_p)++;
2134 	return 0;
2135 }
2136 
2137 static int tc_dump_tclass_root(struct Qdisc *root, struct sk_buff *skb,
2138 			       struct tcmsg *tcm, struct netlink_callback *cb,
2139 			       int *t_p, int s_t)
2140 {
2141 	struct Qdisc *q;
2142 	int b;
2143 
2144 	if (!root)
2145 		return 0;
2146 
2147 	if (tc_dump_tclass_qdisc(root, skb, tcm, cb, t_p, s_t) < 0)
2148 		return -1;
2149 
2150 	if (!qdisc_dev(root))
2151 		return 0;
2152 
2153 	if (tcm->tcm_parent) {
2154 		q = qdisc_match_from_root(root, TC_H_MAJ(tcm->tcm_parent));
2155 		if (q && q != root &&
2156 		    tc_dump_tclass_qdisc(q, skb, tcm, cb, t_p, s_t) < 0)
2157 			return -1;
2158 		return 0;
2159 	}
2160 	hash_for_each(qdisc_dev(root)->qdisc_hash, b, q, hash) {
2161 		if (tc_dump_tclass_qdisc(q, skb, tcm, cb, t_p, s_t) < 0)
2162 			return -1;
2163 	}
2164 
2165 	return 0;
2166 }
2167 
2168 static int tc_dump_tclass(struct sk_buff *skb, struct netlink_callback *cb)
2169 {
2170 	struct tcmsg *tcm = nlmsg_data(cb->nlh);
2171 	struct net *net = sock_net(skb->sk);
2172 	struct netdev_queue *dev_queue;
2173 	struct net_device *dev;
2174 	int t, s_t;
2175 
2176 	if (nlmsg_len(cb->nlh) < sizeof(*tcm))
2177 		return 0;
2178 	dev = dev_get_by_index(net, tcm->tcm_ifindex);
2179 	if (!dev)
2180 		return 0;
2181 
2182 	s_t = cb->args[0];
2183 	t = 0;
2184 
2185 	if (tc_dump_tclass_root(dev->qdisc, skb, tcm, cb, &t, s_t) < 0)
2186 		goto done;
2187 
2188 	dev_queue = dev_ingress_queue(dev);
2189 	if (dev_queue &&
2190 	    tc_dump_tclass_root(dev_queue->qdisc_sleeping, skb, tcm, cb,
2191 				&t, s_t) < 0)
2192 		goto done;
2193 
2194 done:
2195 	cb->args[0] = t;
2196 
2197 	dev_put(dev);
2198 	return skb->len;
2199 }
2200 
2201 #ifdef CONFIG_PROC_FS
2202 static int psched_show(struct seq_file *seq, void *v)
2203 {
2204 	seq_printf(seq, "%08x %08x %08x %08x\n",
2205 		   (u32)NSEC_PER_USEC, (u32)PSCHED_TICKS2NS(1),
2206 		   1000000,
2207 		   (u32)NSEC_PER_SEC / hrtimer_resolution);
2208 
2209 	return 0;
2210 }
2211 
2212 static int __net_init psched_net_init(struct net *net)
2213 {
2214 	struct proc_dir_entry *e;
2215 
2216 	e = proc_create_single("psched", 0, net->proc_net, psched_show);
2217 	if (e == NULL)
2218 		return -ENOMEM;
2219 
2220 	return 0;
2221 }
2222 
2223 static void __net_exit psched_net_exit(struct net *net)
2224 {
2225 	remove_proc_entry("psched", net->proc_net);
2226 }
2227 #else
2228 static int __net_init psched_net_init(struct net *net)
2229 {
2230 	return 0;
2231 }
2232 
2233 static void __net_exit psched_net_exit(struct net *net)
2234 {
2235 }
2236 #endif
2237 
2238 static struct pernet_operations psched_net_ops = {
2239 	.init = psched_net_init,
2240 	.exit = psched_net_exit,
2241 };
2242 
2243 static int __init pktsched_init(void)
2244 {
2245 	int err;
2246 
2247 	err = register_pernet_subsys(&psched_net_ops);
2248 	if (err) {
2249 		pr_err("pktsched_init: "
2250 		       "cannot initialize per netns operations\n");
2251 		return err;
2252 	}
2253 
2254 	register_qdisc(&pfifo_fast_ops);
2255 	register_qdisc(&pfifo_qdisc_ops);
2256 	register_qdisc(&bfifo_qdisc_ops);
2257 	register_qdisc(&pfifo_head_drop_qdisc_ops);
2258 	register_qdisc(&mq_qdisc_ops);
2259 	register_qdisc(&noqueue_qdisc_ops);
2260 
2261 	rtnl_register(PF_UNSPEC, RTM_NEWQDISC, tc_modify_qdisc, NULL, 0);
2262 	rtnl_register(PF_UNSPEC, RTM_DELQDISC, tc_get_qdisc, NULL, 0);
2263 	rtnl_register(PF_UNSPEC, RTM_GETQDISC, tc_get_qdisc, tc_dump_qdisc,
2264 		      0);
2265 	rtnl_register(PF_UNSPEC, RTM_NEWTCLASS, tc_ctl_tclass, NULL, 0);
2266 	rtnl_register(PF_UNSPEC, RTM_DELTCLASS, tc_ctl_tclass, NULL, 0);
2267 	rtnl_register(PF_UNSPEC, RTM_GETTCLASS, tc_ctl_tclass, tc_dump_tclass,
2268 		      0);
2269 
2270 	return 0;
2271 }
2272 
2273 subsys_initcall(pktsched_init);
2274