xref: /linux/net/sched/sch_api.c (revision 9a379e77033f02c4a071891afdf0f0a01eff8ccb)
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/lockdep.h>
31 #include <linux/slab.h>
32 #include <linux/hashtable.h>
33 
34 #include <net/net_namespace.h>
35 #include <net/sock.h>
36 #include <net/netlink.h>
37 #include <net/pkt_sched.h>
38 #include <net/pkt_cls.h>
39 
40 /*
41 
42    Short review.
43    -------------
44 
45    This file consists of two interrelated parts:
46 
47    1. queueing disciplines manager frontend.
48    2. traffic classes manager frontend.
49 
50    Generally, queueing discipline ("qdisc") is a black box,
51    which is able to enqueue packets and to dequeue them (when
52    device is ready to send something) in order and at times
53    determined by algorithm hidden in it.
54 
55    qdisc's are divided to two categories:
56    - "queues", which have no internal structure visible from outside.
57    - "schedulers", which split all the packets to "traffic classes",
58      using "packet classifiers" (look at cls_api.c)
59 
60    In turn, classes may have child qdiscs (as rule, queues)
61    attached to them etc. etc. etc.
62 
63    The goal of the routines in this file is to translate
64    information supplied by user in the form of handles
65    to more intelligible for kernel form, to make some sanity
66    checks and part of work, which is common to all qdiscs
67    and to provide rtnetlink notifications.
68 
69    All real intelligent work is done inside qdisc modules.
70 
71 
72 
73    Every discipline has two major routines: enqueue and dequeue.
74 
75    ---dequeue
76 
77    dequeue usually returns a skb to send. It is allowed to return NULL,
78    but it does not mean that queue is empty, it just means that
79    discipline does not want to send anything this time.
80    Queue is really empty if q->q.qlen == 0.
81    For complicated disciplines with multiple queues q->q is not
82    real packet queue, but however q->q.qlen must be valid.
83 
84    ---enqueue
85 
86    enqueue returns 0, if packet was enqueued successfully.
87    If packet (this one or another one) was dropped, it returns
88    not zero error code.
89    NET_XMIT_DROP 	- this packet dropped
90      Expected action: do not backoff, but wait until queue will clear.
91    NET_XMIT_CN	 	- probably this packet enqueued, but another one dropped.
92      Expected action: backoff or ignore
93 
94    Auxiliary routines:
95 
96    ---peek
97 
98    like dequeue but without removing a packet from the queue
99 
100    ---reset
101 
102    returns qdisc to initial state: purge all buffers, clear all
103    timers, counters (except for statistics) etc.
104 
105    ---init
106 
107    initializes newly created qdisc.
108 
109    ---destroy
110 
111    destroys resources allocated by init and during lifetime of qdisc.
112 
113    ---change
114 
115    changes qdisc parameters.
116  */
117 
118 /* Protects list of registered TC modules. It is pure SMP lock. */
119 static DEFINE_RWLOCK(qdisc_mod_lock);
120 
121 
122 /************************************************
123  *	Queueing disciplines manipulation.	*
124  ************************************************/
125 
126 
127 /* The list of all installed queueing disciplines. */
128 
129 static struct Qdisc_ops *qdisc_base;
130 
131 /* Register/unregister queueing discipline */
132 
133 int register_qdisc(struct Qdisc_ops *qops)
134 {
135 	struct Qdisc_ops *q, **qp;
136 	int rc = -EEXIST;
137 
138 	write_lock(&qdisc_mod_lock);
139 	for (qp = &qdisc_base; (q = *qp) != NULL; qp = &q->next)
140 		if (!strcmp(qops->id, q->id))
141 			goto out;
142 
143 	if (qops->enqueue == NULL)
144 		qops->enqueue = noop_qdisc_ops.enqueue;
145 	if (qops->peek == NULL) {
146 		if (qops->dequeue == NULL)
147 			qops->peek = noop_qdisc_ops.peek;
148 		else
149 			goto out_einval;
150 	}
151 	if (qops->dequeue == NULL)
152 		qops->dequeue = noop_qdisc_ops.dequeue;
153 
154 	if (qops->cl_ops) {
155 		const struct Qdisc_class_ops *cops = qops->cl_ops;
156 
157 		if (!(cops->find && cops->walk && cops->leaf))
158 			goto out_einval;
159 
160 		if (cops->tcf_block && !(cops->bind_tcf && cops->unbind_tcf))
161 			goto out_einval;
162 	}
163 
164 	qops->next = NULL;
165 	*qp = qops;
166 	rc = 0;
167 out:
168 	write_unlock(&qdisc_mod_lock);
169 	return rc;
170 
171 out_einval:
172 	rc = -EINVAL;
173 	goto out;
174 }
175 EXPORT_SYMBOL(register_qdisc);
176 
177 int unregister_qdisc(struct Qdisc_ops *qops)
178 {
179 	struct Qdisc_ops *q, **qp;
180 	int err = -ENOENT;
181 
182 	write_lock(&qdisc_mod_lock);
183 	for (qp = &qdisc_base; (q = *qp) != NULL; qp = &q->next)
184 		if (q == qops)
185 			break;
186 	if (q) {
187 		*qp = q->next;
188 		q->next = NULL;
189 		err = 0;
190 	}
191 	write_unlock(&qdisc_mod_lock);
192 	return err;
193 }
194 EXPORT_SYMBOL(unregister_qdisc);
195 
196 /* Get default qdisc if not otherwise specified */
197 void qdisc_get_default(char *name, size_t len)
198 {
199 	read_lock(&qdisc_mod_lock);
200 	strlcpy(name, default_qdisc_ops->id, len);
201 	read_unlock(&qdisc_mod_lock);
202 }
203 
204 static struct Qdisc_ops *qdisc_lookup_default(const char *name)
205 {
206 	struct Qdisc_ops *q = NULL;
207 
208 	for (q = qdisc_base; q; q = q->next) {
209 		if (!strcmp(name, q->id)) {
210 			if (!try_module_get(q->owner))
211 				q = NULL;
212 			break;
213 		}
214 	}
215 
216 	return q;
217 }
218 
219 /* Set new default qdisc to use */
220 int qdisc_set_default(const char *name)
221 {
222 	const struct Qdisc_ops *ops;
223 
224 	if (!capable(CAP_NET_ADMIN))
225 		return -EPERM;
226 
227 	write_lock(&qdisc_mod_lock);
228 	ops = qdisc_lookup_default(name);
229 	if (!ops) {
230 		/* Not found, drop lock and try to load module */
231 		write_unlock(&qdisc_mod_lock);
232 		request_module("sch_%s", name);
233 		write_lock(&qdisc_mod_lock);
234 
235 		ops = qdisc_lookup_default(name);
236 	}
237 
238 	if (ops) {
239 		/* Set new default */
240 		module_put(default_qdisc_ops->owner);
241 		default_qdisc_ops = ops;
242 	}
243 	write_unlock(&qdisc_mod_lock);
244 
245 	return ops ? 0 : -ENOENT;
246 }
247 
248 #ifdef CONFIG_NET_SCH_DEFAULT
249 /* Set default value from kernel config */
250 static int __init sch_default_qdisc(void)
251 {
252 	return qdisc_set_default(CONFIG_DEFAULT_NET_SCH);
253 }
254 late_initcall(sch_default_qdisc);
255 #endif
256 
257 /* We know handle. Find qdisc among all qdisc's attached to device
258  * (root qdisc, all its children, children of children etc.)
259  * Note: caller either uses rtnl or rcu_read_lock()
260  */
261 
262 static struct Qdisc *qdisc_match_from_root(struct Qdisc *root, u32 handle)
263 {
264 	struct Qdisc *q;
265 
266 	if (!qdisc_dev(root))
267 		return (root->handle == handle ? root : NULL);
268 
269 	if (!(root->flags & TCQ_F_BUILTIN) &&
270 	    root->handle == handle)
271 		return root;
272 
273 	hash_for_each_possible_rcu(qdisc_dev(root)->qdisc_hash, q, hash, handle) {
274 		if (q->handle == handle)
275 			return q;
276 	}
277 	return NULL;
278 }
279 
280 void qdisc_hash_add(struct Qdisc *q, bool invisible)
281 {
282 	if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS)) {
283 		ASSERT_RTNL();
284 		hash_add_rcu(qdisc_dev(q)->qdisc_hash, &q->hash, q->handle);
285 		if (invisible)
286 			q->flags |= TCQ_F_INVISIBLE;
287 	}
288 }
289 EXPORT_SYMBOL(qdisc_hash_add);
290 
291 void qdisc_hash_del(struct Qdisc *q)
292 {
293 	if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS)) {
294 		ASSERT_RTNL();
295 		hash_del_rcu(&q->hash);
296 	}
297 }
298 EXPORT_SYMBOL(qdisc_hash_del);
299 
300 struct Qdisc *qdisc_lookup(struct net_device *dev, u32 handle)
301 {
302 	struct Qdisc *q;
303 
304 	if (!handle)
305 		return NULL;
306 	q = qdisc_match_from_root(dev->qdisc, handle);
307 	if (q)
308 		goto out;
309 
310 	if (dev_ingress_queue(dev))
311 		q = qdisc_match_from_root(
312 			dev_ingress_queue(dev)->qdisc_sleeping,
313 			handle);
314 out:
315 	return q;
316 }
317 
318 static struct Qdisc *qdisc_leaf(struct Qdisc *p, u32 classid)
319 {
320 	unsigned long cl;
321 	struct Qdisc *leaf;
322 	const struct Qdisc_class_ops *cops = p->ops->cl_ops;
323 
324 	if (cops == NULL)
325 		return NULL;
326 	cl = cops->find(p, classid);
327 
328 	if (cl == 0)
329 		return NULL;
330 	leaf = cops->leaf(p, cl);
331 	return leaf;
332 }
333 
334 /* Find queueing discipline by name */
335 
336 static struct Qdisc_ops *qdisc_lookup_ops(struct nlattr *kind)
337 {
338 	struct Qdisc_ops *q = NULL;
339 
340 	if (kind) {
341 		read_lock(&qdisc_mod_lock);
342 		for (q = qdisc_base; q; q = q->next) {
343 			if (nla_strcmp(kind, q->id) == 0) {
344 				if (!try_module_get(q->owner))
345 					q = NULL;
346 				break;
347 			}
348 		}
349 		read_unlock(&qdisc_mod_lock);
350 	}
351 	return q;
352 }
353 
354 /* The linklayer setting were not transferred from iproute2, in older
355  * versions, and the rate tables lookup systems have been dropped in
356  * the kernel. To keep backward compatible with older iproute2 tc
357  * utils, we detect the linklayer setting by detecting if the rate
358  * table were modified.
359  *
360  * For linklayer ATM table entries, the rate table will be aligned to
361  * 48 bytes, thus some table entries will contain the same value.  The
362  * mpu (min packet unit) is also encoded into the old rate table, thus
363  * starting from the mpu, we find low and high table entries for
364  * mapping this cell.  If these entries contain the same value, when
365  * the rate tables have been modified for linklayer ATM.
366  *
367  * This is done by rounding mpu to the nearest 48 bytes cell/entry,
368  * and then roundup to the next cell, calc the table entry one below,
369  * and compare.
370  */
371 static __u8 __detect_linklayer(struct tc_ratespec *r, __u32 *rtab)
372 {
373 	int low       = roundup(r->mpu, 48);
374 	int high      = roundup(low+1, 48);
375 	int cell_low  = low >> r->cell_log;
376 	int cell_high = (high >> r->cell_log) - 1;
377 
378 	/* rtab is too inaccurate at rates > 100Mbit/s */
379 	if ((r->rate > (100000000/8)) || (rtab[0] == 0)) {
380 		pr_debug("TC linklayer: Giving up ATM detection\n");
381 		return TC_LINKLAYER_ETHERNET;
382 	}
383 
384 	if ((cell_high > cell_low) && (cell_high < 256)
385 	    && (rtab[cell_low] == rtab[cell_high])) {
386 		pr_debug("TC linklayer: Detected ATM, low(%d)=high(%d)=%u\n",
387 			 cell_low, cell_high, rtab[cell_high]);
388 		return TC_LINKLAYER_ATM;
389 	}
390 	return TC_LINKLAYER_ETHERNET;
391 }
392 
393 static struct qdisc_rate_table *qdisc_rtab_list;
394 
395 struct qdisc_rate_table *qdisc_get_rtab(struct tc_ratespec *r,
396 					struct nlattr *tab,
397 					struct netlink_ext_ack *extack)
398 {
399 	struct qdisc_rate_table *rtab;
400 
401 	if (tab == NULL || r->rate == 0 || r->cell_log == 0 ||
402 	    nla_len(tab) != TC_RTAB_SIZE) {
403 		NL_SET_ERR_MSG(extack, "Invalid rate table parameters for searching");
404 		return NULL;
405 	}
406 
407 	for (rtab = qdisc_rtab_list; rtab; rtab = rtab->next) {
408 		if (!memcmp(&rtab->rate, r, sizeof(struct tc_ratespec)) &&
409 		    !memcmp(&rtab->data, nla_data(tab), 1024)) {
410 			rtab->refcnt++;
411 			return rtab;
412 		}
413 	}
414 
415 	rtab = kmalloc(sizeof(*rtab), GFP_KERNEL);
416 	if (rtab) {
417 		rtab->rate = *r;
418 		rtab->refcnt = 1;
419 		memcpy(rtab->data, nla_data(tab), 1024);
420 		if (r->linklayer == TC_LINKLAYER_UNAWARE)
421 			r->linklayer = __detect_linklayer(r, rtab->data);
422 		rtab->next = qdisc_rtab_list;
423 		qdisc_rtab_list = rtab;
424 	} else {
425 		NL_SET_ERR_MSG(extack, "Failed to allocate new qdisc rate table");
426 	}
427 	return rtab;
428 }
429 EXPORT_SYMBOL(qdisc_get_rtab);
430 
431 void qdisc_put_rtab(struct qdisc_rate_table *tab)
432 {
433 	struct qdisc_rate_table *rtab, **rtabp;
434 
435 	if (!tab || --tab->refcnt)
436 		return;
437 
438 	for (rtabp = &qdisc_rtab_list;
439 	     (rtab = *rtabp) != NULL;
440 	     rtabp = &rtab->next) {
441 		if (rtab == tab) {
442 			*rtabp = rtab->next;
443 			kfree(rtab);
444 			return;
445 		}
446 	}
447 }
448 EXPORT_SYMBOL(qdisc_put_rtab);
449 
450 static LIST_HEAD(qdisc_stab_list);
451 
452 static const struct nla_policy stab_policy[TCA_STAB_MAX + 1] = {
453 	[TCA_STAB_BASE]	= { .len = sizeof(struct tc_sizespec) },
454 	[TCA_STAB_DATA] = { .type = NLA_BINARY },
455 };
456 
457 static struct qdisc_size_table *qdisc_get_stab(struct nlattr *opt,
458 					       struct netlink_ext_ack *extack)
459 {
460 	struct nlattr *tb[TCA_STAB_MAX + 1];
461 	struct qdisc_size_table *stab;
462 	struct tc_sizespec *s;
463 	unsigned int tsize = 0;
464 	u16 *tab = NULL;
465 	int err;
466 
467 	err = nla_parse_nested(tb, TCA_STAB_MAX, opt, stab_policy, extack);
468 	if (err < 0)
469 		return ERR_PTR(err);
470 	if (!tb[TCA_STAB_BASE]) {
471 		NL_SET_ERR_MSG(extack, "Size table base attribute is missing");
472 		return ERR_PTR(-EINVAL);
473 	}
474 
475 	s = nla_data(tb[TCA_STAB_BASE]);
476 
477 	if (s->tsize > 0) {
478 		if (!tb[TCA_STAB_DATA]) {
479 			NL_SET_ERR_MSG(extack, "Size table data attribute is missing");
480 			return ERR_PTR(-EINVAL);
481 		}
482 		tab = nla_data(tb[TCA_STAB_DATA]);
483 		tsize = nla_len(tb[TCA_STAB_DATA]) / sizeof(u16);
484 	}
485 
486 	if (tsize != s->tsize || (!tab && tsize > 0)) {
487 		NL_SET_ERR_MSG(extack, "Invalid size of size table");
488 		return ERR_PTR(-EINVAL);
489 	}
490 
491 	list_for_each_entry(stab, &qdisc_stab_list, list) {
492 		if (memcmp(&stab->szopts, s, sizeof(*s)))
493 			continue;
494 		if (tsize > 0 && memcmp(stab->data, tab, tsize * sizeof(u16)))
495 			continue;
496 		stab->refcnt++;
497 		return stab;
498 	}
499 
500 	stab = kmalloc(sizeof(*stab) + tsize * sizeof(u16), GFP_KERNEL);
501 	if (!stab)
502 		return ERR_PTR(-ENOMEM);
503 
504 	stab->refcnt = 1;
505 	stab->szopts = *s;
506 	if (tsize > 0)
507 		memcpy(stab->data, tab, tsize * sizeof(u16));
508 
509 	list_add_tail(&stab->list, &qdisc_stab_list);
510 
511 	return stab;
512 }
513 
514 static void stab_kfree_rcu(struct rcu_head *head)
515 {
516 	kfree(container_of(head, struct qdisc_size_table, rcu));
517 }
518 
519 void qdisc_put_stab(struct qdisc_size_table *tab)
520 {
521 	if (!tab)
522 		return;
523 
524 	if (--tab->refcnt == 0) {
525 		list_del(&tab->list);
526 		call_rcu_bh(&tab->rcu, stab_kfree_rcu);
527 	}
528 }
529 EXPORT_SYMBOL(qdisc_put_stab);
530 
531 static int qdisc_dump_stab(struct sk_buff *skb, struct qdisc_size_table *stab)
532 {
533 	struct nlattr *nest;
534 
535 	nest = nla_nest_start(skb, TCA_STAB);
536 	if (nest == NULL)
537 		goto nla_put_failure;
538 	if (nla_put(skb, TCA_STAB_BASE, sizeof(stab->szopts), &stab->szopts))
539 		goto nla_put_failure;
540 	nla_nest_end(skb, nest);
541 
542 	return skb->len;
543 
544 nla_put_failure:
545 	return -1;
546 }
547 
548 void __qdisc_calculate_pkt_len(struct sk_buff *skb,
549 			       const struct qdisc_size_table *stab)
550 {
551 	int pkt_len, slot;
552 
553 	pkt_len = skb->len + stab->szopts.overhead;
554 	if (unlikely(!stab->szopts.tsize))
555 		goto out;
556 
557 	slot = pkt_len + stab->szopts.cell_align;
558 	if (unlikely(slot < 0))
559 		slot = 0;
560 
561 	slot >>= stab->szopts.cell_log;
562 	if (likely(slot < stab->szopts.tsize))
563 		pkt_len = stab->data[slot];
564 	else
565 		pkt_len = stab->data[stab->szopts.tsize - 1] *
566 				(slot / stab->szopts.tsize) +
567 				stab->data[slot % stab->szopts.tsize];
568 
569 	pkt_len <<= stab->szopts.size_log;
570 out:
571 	if (unlikely(pkt_len < 1))
572 		pkt_len = 1;
573 	qdisc_skb_cb(skb)->pkt_len = pkt_len;
574 }
575 EXPORT_SYMBOL(__qdisc_calculate_pkt_len);
576 
577 void qdisc_warn_nonwc(const char *txt, struct Qdisc *qdisc)
578 {
579 	if (!(qdisc->flags & TCQ_F_WARN_NONWC)) {
580 		pr_warn("%s: %s qdisc %X: is non-work-conserving?\n",
581 			txt, qdisc->ops->id, qdisc->handle >> 16);
582 		qdisc->flags |= TCQ_F_WARN_NONWC;
583 	}
584 }
585 EXPORT_SYMBOL(qdisc_warn_nonwc);
586 
587 static enum hrtimer_restart qdisc_watchdog(struct hrtimer *timer)
588 {
589 	struct qdisc_watchdog *wd = container_of(timer, struct qdisc_watchdog,
590 						 timer);
591 
592 	rcu_read_lock();
593 	__netif_schedule(qdisc_root(wd->qdisc));
594 	rcu_read_unlock();
595 
596 	return HRTIMER_NORESTART;
597 }
598 
599 void qdisc_watchdog_init(struct qdisc_watchdog *wd, struct Qdisc *qdisc)
600 {
601 	hrtimer_init(&wd->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
602 	wd->timer.function = qdisc_watchdog;
603 	wd->qdisc = qdisc;
604 }
605 EXPORT_SYMBOL(qdisc_watchdog_init);
606 
607 void qdisc_watchdog_schedule_ns(struct qdisc_watchdog *wd, u64 expires)
608 {
609 	if (test_bit(__QDISC_STATE_DEACTIVATED,
610 		     &qdisc_root_sleeping(wd->qdisc)->state))
611 		return;
612 
613 	if (wd->last_expires == expires)
614 		return;
615 
616 	wd->last_expires = expires;
617 	hrtimer_start(&wd->timer,
618 		      ns_to_ktime(expires),
619 		      HRTIMER_MODE_ABS_PINNED);
620 }
621 EXPORT_SYMBOL(qdisc_watchdog_schedule_ns);
622 
623 void qdisc_watchdog_cancel(struct qdisc_watchdog *wd)
624 {
625 	hrtimer_cancel(&wd->timer);
626 }
627 EXPORT_SYMBOL(qdisc_watchdog_cancel);
628 
629 static struct hlist_head *qdisc_class_hash_alloc(unsigned int n)
630 {
631 	struct hlist_head *h;
632 	unsigned int i;
633 
634 	h = kvmalloc_array(n, sizeof(struct hlist_head), GFP_KERNEL);
635 
636 	if (h != NULL) {
637 		for (i = 0; i < n; i++)
638 			INIT_HLIST_HEAD(&h[i]);
639 	}
640 	return h;
641 }
642 
643 void qdisc_class_hash_grow(struct Qdisc *sch, struct Qdisc_class_hash *clhash)
644 {
645 	struct Qdisc_class_common *cl;
646 	struct hlist_node *next;
647 	struct hlist_head *nhash, *ohash;
648 	unsigned int nsize, nmask, osize;
649 	unsigned int i, h;
650 
651 	/* Rehash when load factor exceeds 0.75 */
652 	if (clhash->hashelems * 4 <= clhash->hashsize * 3)
653 		return;
654 	nsize = clhash->hashsize * 2;
655 	nmask = nsize - 1;
656 	nhash = qdisc_class_hash_alloc(nsize);
657 	if (nhash == NULL)
658 		return;
659 
660 	ohash = clhash->hash;
661 	osize = clhash->hashsize;
662 
663 	sch_tree_lock(sch);
664 	for (i = 0; i < osize; i++) {
665 		hlist_for_each_entry_safe(cl, next, &ohash[i], hnode) {
666 			h = qdisc_class_hash(cl->classid, nmask);
667 			hlist_add_head(&cl->hnode, &nhash[h]);
668 		}
669 	}
670 	clhash->hash     = nhash;
671 	clhash->hashsize = nsize;
672 	clhash->hashmask = nmask;
673 	sch_tree_unlock(sch);
674 
675 	kvfree(ohash);
676 }
677 EXPORT_SYMBOL(qdisc_class_hash_grow);
678 
679 int qdisc_class_hash_init(struct Qdisc_class_hash *clhash)
680 {
681 	unsigned int size = 4;
682 
683 	clhash->hash = qdisc_class_hash_alloc(size);
684 	if (!clhash->hash)
685 		return -ENOMEM;
686 	clhash->hashsize  = size;
687 	clhash->hashmask  = size - 1;
688 	clhash->hashelems = 0;
689 	return 0;
690 }
691 EXPORT_SYMBOL(qdisc_class_hash_init);
692 
693 void qdisc_class_hash_destroy(struct Qdisc_class_hash *clhash)
694 {
695 	kvfree(clhash->hash);
696 }
697 EXPORT_SYMBOL(qdisc_class_hash_destroy);
698 
699 void qdisc_class_hash_insert(struct Qdisc_class_hash *clhash,
700 			     struct Qdisc_class_common *cl)
701 {
702 	unsigned int h;
703 
704 	INIT_HLIST_NODE(&cl->hnode);
705 	h = qdisc_class_hash(cl->classid, clhash->hashmask);
706 	hlist_add_head(&cl->hnode, &clhash->hash[h]);
707 	clhash->hashelems++;
708 }
709 EXPORT_SYMBOL(qdisc_class_hash_insert);
710 
711 void qdisc_class_hash_remove(struct Qdisc_class_hash *clhash,
712 			     struct Qdisc_class_common *cl)
713 {
714 	hlist_del(&cl->hnode);
715 	clhash->hashelems--;
716 }
717 EXPORT_SYMBOL(qdisc_class_hash_remove);
718 
719 /* Allocate an unique handle from space managed by kernel
720  * Possible range is [8000-FFFF]:0000 (0x8000 values)
721  */
722 static u32 qdisc_alloc_handle(struct net_device *dev)
723 {
724 	int i = 0x8000;
725 	static u32 autohandle = TC_H_MAKE(0x80000000U, 0);
726 
727 	do {
728 		autohandle += TC_H_MAKE(0x10000U, 0);
729 		if (autohandle == TC_H_MAKE(TC_H_ROOT, 0))
730 			autohandle = TC_H_MAKE(0x80000000U, 0);
731 		if (!qdisc_lookup(dev, autohandle))
732 			return autohandle;
733 		cond_resched();
734 	} while	(--i > 0);
735 
736 	return 0;
737 }
738 
739 void qdisc_tree_reduce_backlog(struct Qdisc *sch, unsigned int n,
740 			       unsigned int len)
741 {
742 	const struct Qdisc_class_ops *cops;
743 	unsigned long cl;
744 	u32 parentid;
745 	bool notify;
746 	int drops;
747 
748 	if (n == 0 && len == 0)
749 		return;
750 	drops = max_t(int, n, 0);
751 	rcu_read_lock();
752 	while ((parentid = sch->parent)) {
753 		if (TC_H_MAJ(parentid) == TC_H_MAJ(TC_H_INGRESS))
754 			break;
755 
756 		if (sch->flags & TCQ_F_NOPARENT)
757 			break;
758 		/* Notify parent qdisc only if child qdisc becomes empty.
759 		 *
760 		 * If child was empty even before update then backlog
761 		 * counter is screwed and we skip notification because
762 		 * parent class is already passive.
763 		 */
764 		notify = !sch->q.qlen && !WARN_ON_ONCE(!n);
765 		/* TODO: perform the search on a per txq basis */
766 		sch = qdisc_lookup(qdisc_dev(sch), TC_H_MAJ(parentid));
767 		if (sch == NULL) {
768 			WARN_ON_ONCE(parentid != TC_H_ROOT);
769 			break;
770 		}
771 		cops = sch->ops->cl_ops;
772 		if (notify && cops->qlen_notify) {
773 			cl = cops->find(sch, parentid);
774 			cops->qlen_notify(sch, cl);
775 		}
776 		sch->q.qlen -= n;
777 		sch->qstats.backlog -= len;
778 		__qdisc_qstats_drop(sch, drops);
779 	}
780 	rcu_read_unlock();
781 }
782 EXPORT_SYMBOL(qdisc_tree_reduce_backlog);
783 
784 static int tc_fill_qdisc(struct sk_buff *skb, struct Qdisc *q, u32 clid,
785 			 u32 portid, u32 seq, u16 flags, int event)
786 {
787 	struct gnet_stats_basic_cpu __percpu *cpu_bstats = NULL;
788 	struct gnet_stats_queue __percpu *cpu_qstats = NULL;
789 	struct tcmsg *tcm;
790 	struct nlmsghdr  *nlh;
791 	unsigned char *b = skb_tail_pointer(skb);
792 	struct gnet_dump d;
793 	struct qdisc_size_table *stab;
794 	u32 block_index;
795 	__u32 qlen;
796 
797 	cond_resched();
798 	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*tcm), flags);
799 	if (!nlh)
800 		goto out_nlmsg_trim;
801 	tcm = nlmsg_data(nlh);
802 	tcm->tcm_family = AF_UNSPEC;
803 	tcm->tcm__pad1 = 0;
804 	tcm->tcm__pad2 = 0;
805 	tcm->tcm_ifindex = qdisc_dev(q)->ifindex;
806 	tcm->tcm_parent = clid;
807 	tcm->tcm_handle = q->handle;
808 	tcm->tcm_info = refcount_read(&q->refcnt);
809 	if (nla_put_string(skb, TCA_KIND, q->ops->id))
810 		goto nla_put_failure;
811 	if (q->ops->ingress_block_get) {
812 		block_index = q->ops->ingress_block_get(q);
813 		if (block_index &&
814 		    nla_put_u32(skb, TCA_INGRESS_BLOCK, block_index))
815 			goto nla_put_failure;
816 	}
817 	if (q->ops->egress_block_get) {
818 		block_index = q->ops->egress_block_get(q);
819 		if (block_index &&
820 		    nla_put_u32(skb, TCA_EGRESS_BLOCK, block_index))
821 			goto nla_put_failure;
822 	}
823 	if (q->ops->dump && q->ops->dump(q, skb) < 0)
824 		goto nla_put_failure;
825 	if (nla_put_u8(skb, TCA_HW_OFFLOAD, !!(q->flags & TCQ_F_OFFLOADED)))
826 		goto nla_put_failure;
827 	qlen = qdisc_qlen_sum(q);
828 
829 	stab = rtnl_dereference(q->stab);
830 	if (stab && qdisc_dump_stab(skb, stab) < 0)
831 		goto nla_put_failure;
832 
833 	if (gnet_stats_start_copy_compat(skb, TCA_STATS2, TCA_STATS, TCA_XSTATS,
834 					 NULL, &d, TCA_PAD) < 0)
835 		goto nla_put_failure;
836 
837 	if (q->ops->dump_stats && q->ops->dump_stats(q, &d) < 0)
838 		goto nla_put_failure;
839 
840 	if (qdisc_is_percpu_stats(q)) {
841 		cpu_bstats = q->cpu_bstats;
842 		cpu_qstats = q->cpu_qstats;
843 	}
844 
845 	if (gnet_stats_copy_basic(qdisc_root_sleeping_running(q),
846 				  &d, cpu_bstats, &q->bstats) < 0 ||
847 	    gnet_stats_copy_rate_est(&d, &q->rate_est) < 0 ||
848 	    gnet_stats_copy_queue(&d, cpu_qstats, &q->qstats, qlen) < 0)
849 		goto nla_put_failure;
850 
851 	if (gnet_stats_finish_copy(&d) < 0)
852 		goto nla_put_failure;
853 
854 	nlh->nlmsg_len = skb_tail_pointer(skb) - b;
855 	return skb->len;
856 
857 out_nlmsg_trim:
858 nla_put_failure:
859 	nlmsg_trim(skb, b);
860 	return -1;
861 }
862 
863 static bool tc_qdisc_dump_ignore(struct Qdisc *q, bool dump_invisible)
864 {
865 	if (q->flags & TCQ_F_BUILTIN)
866 		return true;
867 	if ((q->flags & TCQ_F_INVISIBLE) && !dump_invisible)
868 		return true;
869 
870 	return false;
871 }
872 
873 static int qdisc_notify(struct net *net, struct sk_buff *oskb,
874 			struct nlmsghdr *n, u32 clid,
875 			struct Qdisc *old, struct Qdisc *new)
876 {
877 	struct sk_buff *skb;
878 	u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
879 
880 	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
881 	if (!skb)
882 		return -ENOBUFS;
883 
884 	if (old && !tc_qdisc_dump_ignore(old, false)) {
885 		if (tc_fill_qdisc(skb, old, clid, portid, n->nlmsg_seq,
886 				  0, RTM_DELQDISC) < 0)
887 			goto err_out;
888 	}
889 	if (new && !tc_qdisc_dump_ignore(new, false)) {
890 		if (tc_fill_qdisc(skb, new, clid, portid, n->nlmsg_seq,
891 				  old ? NLM_F_REPLACE : 0, RTM_NEWQDISC) < 0)
892 			goto err_out;
893 	}
894 
895 	if (skb->len)
896 		return rtnetlink_send(skb, net, portid, RTNLGRP_TC,
897 				      n->nlmsg_flags & NLM_F_ECHO);
898 
899 err_out:
900 	kfree_skb(skb);
901 	return -EINVAL;
902 }
903 
904 static void notify_and_destroy(struct net *net, struct sk_buff *skb,
905 			       struct nlmsghdr *n, u32 clid,
906 			       struct Qdisc *old, struct Qdisc *new)
907 {
908 	if (new || old)
909 		qdisc_notify(net, skb, n, clid, old, new);
910 
911 	if (old)
912 		qdisc_destroy(old);
913 }
914 
915 /* Graft qdisc "new" to class "classid" of qdisc "parent" or
916  * to device "dev".
917  *
918  * When appropriate send a netlink notification using 'skb'
919  * and "n".
920  *
921  * On success, destroy old qdisc.
922  */
923 
924 static int qdisc_graft(struct net_device *dev, struct Qdisc *parent,
925 		       struct sk_buff *skb, struct nlmsghdr *n, u32 classid,
926 		       struct Qdisc *new, struct Qdisc *old,
927 		       struct netlink_ext_ack *extack)
928 {
929 	struct Qdisc *q = old;
930 	struct net *net = dev_net(dev);
931 	int err = 0;
932 
933 	if (parent == NULL) {
934 		unsigned int i, num_q, ingress;
935 
936 		ingress = 0;
937 		num_q = dev->num_tx_queues;
938 		if ((q && q->flags & TCQ_F_INGRESS) ||
939 		    (new && new->flags & TCQ_F_INGRESS)) {
940 			num_q = 1;
941 			ingress = 1;
942 			if (!dev_ingress_queue(dev)) {
943 				NL_SET_ERR_MSG(extack, "Device does not have an ingress queue");
944 				return -ENOENT;
945 			}
946 		}
947 
948 		if (dev->flags & IFF_UP)
949 			dev_deactivate(dev);
950 
951 		if (new && new->ops->attach)
952 			goto skip;
953 
954 		for (i = 0; i < num_q; i++) {
955 			struct netdev_queue *dev_queue = dev_ingress_queue(dev);
956 
957 			if (!ingress)
958 				dev_queue = netdev_get_tx_queue(dev, i);
959 
960 			old = dev_graft_qdisc(dev_queue, new);
961 			if (new && i > 0)
962 				qdisc_refcount_inc(new);
963 
964 			if (!ingress)
965 				qdisc_destroy(old);
966 		}
967 
968 skip:
969 		if (!ingress) {
970 			notify_and_destroy(net, skb, n, classid,
971 					   dev->qdisc, new);
972 			if (new && !new->ops->attach)
973 				qdisc_refcount_inc(new);
974 			dev->qdisc = new ? : &noop_qdisc;
975 
976 			if (new && new->ops->attach)
977 				new->ops->attach(new);
978 		} else {
979 			notify_and_destroy(net, skb, n, classid, old, new);
980 		}
981 
982 		if (dev->flags & IFF_UP)
983 			dev_activate(dev);
984 	} else {
985 		const struct Qdisc_class_ops *cops = parent->ops->cl_ops;
986 
987 		/* Only support running class lockless if parent is lockless */
988 		if (new && (new->flags & TCQ_F_NOLOCK) &&
989 		    parent && !(parent->flags & TCQ_F_NOLOCK))
990 			new->flags &= ~TCQ_F_NOLOCK;
991 
992 		err = -EOPNOTSUPP;
993 		if (cops && cops->graft) {
994 			unsigned long cl = cops->find(parent, classid);
995 
996 			if (cl) {
997 				err = cops->graft(parent, cl, new, &old,
998 						  extack);
999 			} else {
1000 				NL_SET_ERR_MSG(extack, "Specified class not found");
1001 				err = -ENOENT;
1002 			}
1003 		}
1004 		if (!err)
1005 			notify_and_destroy(net, skb, n, classid, old, new);
1006 	}
1007 	return err;
1008 }
1009 
1010 static int qdisc_block_indexes_set(struct Qdisc *sch, struct nlattr **tca,
1011 				   struct netlink_ext_ack *extack)
1012 {
1013 	u32 block_index;
1014 
1015 	if (tca[TCA_INGRESS_BLOCK]) {
1016 		block_index = nla_get_u32(tca[TCA_INGRESS_BLOCK]);
1017 
1018 		if (!block_index) {
1019 			NL_SET_ERR_MSG(extack, "Ingress block index cannot be 0");
1020 			return -EINVAL;
1021 		}
1022 		if (!sch->ops->ingress_block_set) {
1023 			NL_SET_ERR_MSG(extack, "Ingress block sharing is not supported");
1024 			return -EOPNOTSUPP;
1025 		}
1026 		sch->ops->ingress_block_set(sch, block_index);
1027 	}
1028 	if (tca[TCA_EGRESS_BLOCK]) {
1029 		block_index = nla_get_u32(tca[TCA_EGRESS_BLOCK]);
1030 
1031 		if (!block_index) {
1032 			NL_SET_ERR_MSG(extack, "Egress block index cannot be 0");
1033 			return -EINVAL;
1034 		}
1035 		if (!sch->ops->egress_block_set) {
1036 			NL_SET_ERR_MSG(extack, "Egress block sharing is not supported");
1037 			return -EOPNOTSUPP;
1038 		}
1039 		sch->ops->egress_block_set(sch, block_index);
1040 	}
1041 	return 0;
1042 }
1043 
1044 /* lockdep annotation is needed for ingress; egress gets it only for name */
1045 static struct lock_class_key qdisc_tx_lock;
1046 static struct lock_class_key qdisc_rx_lock;
1047 
1048 /*
1049    Allocate and initialize new qdisc.
1050 
1051    Parameters are passed via opt.
1052  */
1053 
1054 static struct Qdisc *qdisc_create(struct net_device *dev,
1055 				  struct netdev_queue *dev_queue,
1056 				  struct Qdisc *p, u32 parent, u32 handle,
1057 				  struct nlattr **tca, int *errp,
1058 				  struct netlink_ext_ack *extack)
1059 {
1060 	int err;
1061 	struct nlattr *kind = tca[TCA_KIND];
1062 	struct Qdisc *sch;
1063 	struct Qdisc_ops *ops;
1064 	struct qdisc_size_table *stab;
1065 
1066 	ops = qdisc_lookup_ops(kind);
1067 #ifdef CONFIG_MODULES
1068 	if (ops == NULL && kind != NULL) {
1069 		char name[IFNAMSIZ];
1070 		if (nla_strlcpy(name, kind, IFNAMSIZ) < IFNAMSIZ) {
1071 			/* We dropped the RTNL semaphore in order to
1072 			 * perform the module load.  So, even if we
1073 			 * succeeded in loading the module we have to
1074 			 * tell the caller to replay the request.  We
1075 			 * indicate this using -EAGAIN.
1076 			 * We replay the request because the device may
1077 			 * go away in the mean time.
1078 			 */
1079 			rtnl_unlock();
1080 			request_module("sch_%s", name);
1081 			rtnl_lock();
1082 			ops = qdisc_lookup_ops(kind);
1083 			if (ops != NULL) {
1084 				/* We will try again qdisc_lookup_ops,
1085 				 * so don't keep a reference.
1086 				 */
1087 				module_put(ops->owner);
1088 				err = -EAGAIN;
1089 				goto err_out;
1090 			}
1091 		}
1092 	}
1093 #endif
1094 
1095 	err = -ENOENT;
1096 	if (!ops) {
1097 		NL_SET_ERR_MSG(extack, "Specified qdisc not found");
1098 		goto err_out;
1099 	}
1100 
1101 	sch = qdisc_alloc(dev_queue, ops, extack);
1102 	if (IS_ERR(sch)) {
1103 		err = PTR_ERR(sch);
1104 		goto err_out2;
1105 	}
1106 
1107 	sch->parent = parent;
1108 
1109 	if (handle == TC_H_INGRESS) {
1110 		sch->flags |= TCQ_F_INGRESS;
1111 		handle = TC_H_MAKE(TC_H_INGRESS, 0);
1112 		lockdep_set_class(qdisc_lock(sch), &qdisc_rx_lock);
1113 	} else {
1114 		if (handle == 0) {
1115 			handle = qdisc_alloc_handle(dev);
1116 			err = -ENOMEM;
1117 			if (handle == 0)
1118 				goto err_out3;
1119 		}
1120 		lockdep_set_class(qdisc_lock(sch), &qdisc_tx_lock);
1121 		if (!netif_is_multiqueue(dev))
1122 			sch->flags |= TCQ_F_ONETXQUEUE;
1123 	}
1124 
1125 	sch->handle = handle;
1126 
1127 	/* This exist to keep backward compatible with a userspace
1128 	 * loophole, what allowed userspace to get IFF_NO_QUEUE
1129 	 * facility on older kernels by setting tx_queue_len=0 (prior
1130 	 * to qdisc init), and then forgot to reinit tx_queue_len
1131 	 * before again attaching a qdisc.
1132 	 */
1133 	if ((dev->priv_flags & IFF_NO_QUEUE) && (dev->tx_queue_len == 0)) {
1134 		dev->tx_queue_len = DEFAULT_TX_QUEUE_LEN;
1135 		netdev_info(dev, "Caught tx_queue_len zero misconfig\n");
1136 	}
1137 
1138 	err = qdisc_block_indexes_set(sch, tca, extack);
1139 	if (err)
1140 		goto err_out3;
1141 
1142 	if (ops->init) {
1143 		err = ops->init(sch, tca[TCA_OPTIONS], extack);
1144 		if (err != 0)
1145 			goto err_out5;
1146 	}
1147 
1148 	if (tca[TCA_STAB]) {
1149 		stab = qdisc_get_stab(tca[TCA_STAB], extack);
1150 		if (IS_ERR(stab)) {
1151 			err = PTR_ERR(stab);
1152 			goto err_out4;
1153 		}
1154 		rcu_assign_pointer(sch->stab, stab);
1155 	}
1156 	if (tca[TCA_RATE]) {
1157 		seqcount_t *running;
1158 
1159 		err = -EOPNOTSUPP;
1160 		if (sch->flags & TCQ_F_MQROOT) {
1161 			NL_SET_ERR_MSG(extack, "Cannot attach rate estimator to a multi-queue root qdisc");
1162 			goto err_out4;
1163 		}
1164 
1165 		if (sch->parent != TC_H_ROOT &&
1166 		    !(sch->flags & TCQ_F_INGRESS) &&
1167 		    (!p || !(p->flags & TCQ_F_MQROOT)))
1168 			running = qdisc_root_sleeping_running(sch);
1169 		else
1170 			running = &sch->running;
1171 
1172 		err = gen_new_estimator(&sch->bstats,
1173 					sch->cpu_bstats,
1174 					&sch->rate_est,
1175 					NULL,
1176 					running,
1177 					tca[TCA_RATE]);
1178 		if (err) {
1179 			NL_SET_ERR_MSG(extack, "Failed to generate new estimator");
1180 			goto err_out4;
1181 		}
1182 	}
1183 
1184 	qdisc_hash_add(sch, false);
1185 
1186 	return sch;
1187 
1188 err_out5:
1189 	/* ops->init() failed, we call ->destroy() like qdisc_create_dflt() */
1190 	if (ops->destroy)
1191 		ops->destroy(sch);
1192 err_out3:
1193 	dev_put(dev);
1194 	qdisc_free(sch);
1195 err_out2:
1196 	module_put(ops->owner);
1197 err_out:
1198 	*errp = err;
1199 	return NULL;
1200 
1201 err_out4:
1202 	/*
1203 	 * Any broken qdiscs that would require a ops->reset() here?
1204 	 * The qdisc was never in action so it shouldn't be necessary.
1205 	 */
1206 	qdisc_put_stab(rtnl_dereference(sch->stab));
1207 	if (ops->destroy)
1208 		ops->destroy(sch);
1209 	goto err_out3;
1210 }
1211 
1212 static int qdisc_change(struct Qdisc *sch, struct nlattr **tca,
1213 			struct netlink_ext_ack *extack)
1214 {
1215 	struct qdisc_size_table *ostab, *stab = NULL;
1216 	int err = 0;
1217 
1218 	if (tca[TCA_OPTIONS]) {
1219 		if (!sch->ops->change) {
1220 			NL_SET_ERR_MSG(extack, "Change operation not supported by specified qdisc");
1221 			return -EINVAL;
1222 		}
1223 		if (tca[TCA_INGRESS_BLOCK] || tca[TCA_EGRESS_BLOCK]) {
1224 			NL_SET_ERR_MSG(extack, "Change of blocks is not supported");
1225 			return -EOPNOTSUPP;
1226 		}
1227 		err = sch->ops->change(sch, tca[TCA_OPTIONS], extack);
1228 		if (err)
1229 			return err;
1230 	}
1231 
1232 	if (tca[TCA_STAB]) {
1233 		stab = qdisc_get_stab(tca[TCA_STAB], extack);
1234 		if (IS_ERR(stab))
1235 			return PTR_ERR(stab);
1236 	}
1237 
1238 	ostab = rtnl_dereference(sch->stab);
1239 	rcu_assign_pointer(sch->stab, stab);
1240 	qdisc_put_stab(ostab);
1241 
1242 	if (tca[TCA_RATE]) {
1243 		/* NB: ignores errors from replace_estimator
1244 		   because change can't be undone. */
1245 		if (sch->flags & TCQ_F_MQROOT)
1246 			goto out;
1247 		gen_replace_estimator(&sch->bstats,
1248 				      sch->cpu_bstats,
1249 				      &sch->rate_est,
1250 				      NULL,
1251 				      qdisc_root_sleeping_running(sch),
1252 				      tca[TCA_RATE]);
1253 	}
1254 out:
1255 	return 0;
1256 }
1257 
1258 struct check_loop_arg {
1259 	struct qdisc_walker	w;
1260 	struct Qdisc		*p;
1261 	int			depth;
1262 };
1263 
1264 static int check_loop_fn(struct Qdisc *q, unsigned long cl,
1265 			 struct qdisc_walker *w);
1266 
1267 static int check_loop(struct Qdisc *q, struct Qdisc *p, int depth)
1268 {
1269 	struct check_loop_arg	arg;
1270 
1271 	if (q->ops->cl_ops == NULL)
1272 		return 0;
1273 
1274 	arg.w.stop = arg.w.skip = arg.w.count = 0;
1275 	arg.w.fn = check_loop_fn;
1276 	arg.depth = depth;
1277 	arg.p = p;
1278 	q->ops->cl_ops->walk(q, &arg.w);
1279 	return arg.w.stop ? -ELOOP : 0;
1280 }
1281 
1282 static int
1283 check_loop_fn(struct Qdisc *q, unsigned long cl, struct qdisc_walker *w)
1284 {
1285 	struct Qdisc *leaf;
1286 	const struct Qdisc_class_ops *cops = q->ops->cl_ops;
1287 	struct check_loop_arg *arg = (struct check_loop_arg *)w;
1288 
1289 	leaf = cops->leaf(q, cl);
1290 	if (leaf) {
1291 		if (leaf == arg->p || arg->depth > 7)
1292 			return -ELOOP;
1293 		return check_loop(leaf, arg->p, arg->depth + 1);
1294 	}
1295 	return 0;
1296 }
1297 
1298 /*
1299  * Delete/get qdisc.
1300  */
1301 
1302 static int tc_get_qdisc(struct sk_buff *skb, struct nlmsghdr *n,
1303 			struct netlink_ext_ack *extack)
1304 {
1305 	struct net *net = sock_net(skb->sk);
1306 	struct tcmsg *tcm = nlmsg_data(n);
1307 	struct nlattr *tca[TCA_MAX + 1];
1308 	struct net_device *dev;
1309 	u32 clid;
1310 	struct Qdisc *q = NULL;
1311 	struct Qdisc *p = NULL;
1312 	int err;
1313 
1314 	if ((n->nlmsg_type != RTM_GETQDISC) &&
1315 	    !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
1316 		return -EPERM;
1317 
1318 	err = nlmsg_parse(n, sizeof(*tcm), tca, TCA_MAX, NULL, extack);
1319 	if (err < 0)
1320 		return err;
1321 
1322 	dev = __dev_get_by_index(net, tcm->tcm_ifindex);
1323 	if (!dev)
1324 		return -ENODEV;
1325 
1326 	clid = tcm->tcm_parent;
1327 	if (clid) {
1328 		if (clid != TC_H_ROOT) {
1329 			if (TC_H_MAJ(clid) != TC_H_MAJ(TC_H_INGRESS)) {
1330 				p = qdisc_lookup(dev, TC_H_MAJ(clid));
1331 				if (!p) {
1332 					NL_SET_ERR_MSG(extack, "Failed to find qdisc with specified classid");
1333 					return -ENOENT;
1334 				}
1335 				q = qdisc_leaf(p, clid);
1336 			} else if (dev_ingress_queue(dev)) {
1337 				q = dev_ingress_queue(dev)->qdisc_sleeping;
1338 			}
1339 		} else {
1340 			q = dev->qdisc;
1341 		}
1342 		if (!q) {
1343 			NL_SET_ERR_MSG(extack, "Cannot find specified qdisc on specified device");
1344 			return -ENOENT;
1345 		}
1346 
1347 		if (tcm->tcm_handle && q->handle != tcm->tcm_handle) {
1348 			NL_SET_ERR_MSG(extack, "Invalid handle");
1349 			return -EINVAL;
1350 		}
1351 	} else {
1352 		q = qdisc_lookup(dev, tcm->tcm_handle);
1353 		if (!q) {
1354 			NL_SET_ERR_MSG(extack, "Failed to find qdisc with specified handle");
1355 			return -ENOENT;
1356 		}
1357 	}
1358 
1359 	if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], q->ops->id)) {
1360 		NL_SET_ERR_MSG(extack, "Invalid qdisc name");
1361 		return -EINVAL;
1362 	}
1363 
1364 	if (n->nlmsg_type == RTM_DELQDISC) {
1365 		if (!clid) {
1366 			NL_SET_ERR_MSG(extack, "Classid cannot be zero");
1367 			return -EINVAL;
1368 		}
1369 		if (q->handle == 0) {
1370 			NL_SET_ERR_MSG(extack, "Cannot delete qdisc with handle of zero");
1371 			return -ENOENT;
1372 		}
1373 		err = qdisc_graft(dev, p, skb, n, clid, NULL, q, extack);
1374 		if (err != 0)
1375 			return err;
1376 	} else {
1377 		qdisc_notify(net, skb, n, clid, NULL, q);
1378 	}
1379 	return 0;
1380 }
1381 
1382 /*
1383  * Create/change qdisc.
1384  */
1385 
1386 static int tc_modify_qdisc(struct sk_buff *skb, struct nlmsghdr *n,
1387 			   struct netlink_ext_ack *extack)
1388 {
1389 	struct net *net = sock_net(skb->sk);
1390 	struct tcmsg *tcm;
1391 	struct nlattr *tca[TCA_MAX + 1];
1392 	struct net_device *dev;
1393 	u32 clid;
1394 	struct Qdisc *q, *p;
1395 	int err;
1396 
1397 	if (!netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
1398 		return -EPERM;
1399 
1400 replay:
1401 	/* Reinit, just in case something touches this. */
1402 	err = nlmsg_parse(n, sizeof(*tcm), tca, TCA_MAX, NULL, extack);
1403 	if (err < 0)
1404 		return err;
1405 
1406 	tcm = nlmsg_data(n);
1407 	clid = tcm->tcm_parent;
1408 	q = p = NULL;
1409 
1410 	dev = __dev_get_by_index(net, tcm->tcm_ifindex);
1411 	if (!dev)
1412 		return -ENODEV;
1413 
1414 
1415 	if (clid) {
1416 		if (clid != TC_H_ROOT) {
1417 			if (clid != TC_H_INGRESS) {
1418 				p = qdisc_lookup(dev, TC_H_MAJ(clid));
1419 				if (!p) {
1420 					NL_SET_ERR_MSG(extack, "Failed to find specified qdisc");
1421 					return -ENOENT;
1422 				}
1423 				q = qdisc_leaf(p, clid);
1424 			} else if (dev_ingress_queue_create(dev)) {
1425 				q = dev_ingress_queue(dev)->qdisc_sleeping;
1426 			}
1427 		} else {
1428 			q = dev->qdisc;
1429 		}
1430 
1431 		/* It may be default qdisc, ignore it */
1432 		if (q && q->handle == 0)
1433 			q = NULL;
1434 
1435 		if (!q || !tcm->tcm_handle || q->handle != tcm->tcm_handle) {
1436 			if (tcm->tcm_handle) {
1437 				if (q && !(n->nlmsg_flags & NLM_F_REPLACE)) {
1438 					NL_SET_ERR_MSG(extack, "NLM_F_REPLACE needed to override");
1439 					return -EEXIST;
1440 				}
1441 				if (TC_H_MIN(tcm->tcm_handle)) {
1442 					NL_SET_ERR_MSG(extack, "Invalid minor handle");
1443 					return -EINVAL;
1444 				}
1445 				q = qdisc_lookup(dev, tcm->tcm_handle);
1446 				if (!q)
1447 					goto create_n_graft;
1448 				if (n->nlmsg_flags & NLM_F_EXCL) {
1449 					NL_SET_ERR_MSG(extack, "Exclusivity flag on, cannot override");
1450 					return -EEXIST;
1451 				}
1452 				if (tca[TCA_KIND] &&
1453 				    nla_strcmp(tca[TCA_KIND], q->ops->id)) {
1454 					NL_SET_ERR_MSG(extack, "Invalid qdisc name");
1455 					return -EINVAL;
1456 				}
1457 				if (q == p ||
1458 				    (p && check_loop(q, p, 0))) {
1459 					NL_SET_ERR_MSG(extack, "Qdisc parent/child loop detected");
1460 					return -ELOOP;
1461 				}
1462 				qdisc_refcount_inc(q);
1463 				goto graft;
1464 			} else {
1465 				if (!q)
1466 					goto create_n_graft;
1467 
1468 				/* This magic test requires explanation.
1469 				 *
1470 				 *   We know, that some child q is already
1471 				 *   attached to this parent and have choice:
1472 				 *   either to change it or to create/graft new one.
1473 				 *
1474 				 *   1. We are allowed to create/graft only
1475 				 *   if CREATE and REPLACE flags are set.
1476 				 *
1477 				 *   2. If EXCL is set, requestor wanted to say,
1478 				 *   that qdisc tcm_handle is not expected
1479 				 *   to exist, so that we choose create/graft too.
1480 				 *
1481 				 *   3. The last case is when no flags are set.
1482 				 *   Alas, it is sort of hole in API, we
1483 				 *   cannot decide what to do unambiguously.
1484 				 *   For now we select create/graft, if
1485 				 *   user gave KIND, which does not match existing.
1486 				 */
1487 				if ((n->nlmsg_flags & NLM_F_CREATE) &&
1488 				    (n->nlmsg_flags & NLM_F_REPLACE) &&
1489 				    ((n->nlmsg_flags & NLM_F_EXCL) ||
1490 				     (tca[TCA_KIND] &&
1491 				      nla_strcmp(tca[TCA_KIND], q->ops->id))))
1492 					goto create_n_graft;
1493 			}
1494 		}
1495 	} else {
1496 		if (!tcm->tcm_handle) {
1497 			NL_SET_ERR_MSG(extack, "Handle cannot be zero");
1498 			return -EINVAL;
1499 		}
1500 		q = qdisc_lookup(dev, tcm->tcm_handle);
1501 	}
1502 
1503 	/* Change qdisc parameters */
1504 	if (!q) {
1505 		NL_SET_ERR_MSG(extack, "Specified qdisc not found");
1506 		return -ENOENT;
1507 	}
1508 	if (n->nlmsg_flags & NLM_F_EXCL) {
1509 		NL_SET_ERR_MSG(extack, "Exclusivity flag on, cannot modify");
1510 		return -EEXIST;
1511 	}
1512 	if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], q->ops->id)) {
1513 		NL_SET_ERR_MSG(extack, "Invalid qdisc name");
1514 		return -EINVAL;
1515 	}
1516 	err = qdisc_change(q, tca, extack);
1517 	if (err == 0)
1518 		qdisc_notify(net, skb, n, clid, NULL, q);
1519 	return err;
1520 
1521 create_n_graft:
1522 	if (!(n->nlmsg_flags & NLM_F_CREATE)) {
1523 		NL_SET_ERR_MSG(extack, "Qdisc not found. To create specify NLM_F_CREATE flag");
1524 		return -ENOENT;
1525 	}
1526 	if (clid == TC_H_INGRESS) {
1527 		if (dev_ingress_queue(dev)) {
1528 			q = qdisc_create(dev, dev_ingress_queue(dev), p,
1529 					 tcm->tcm_parent, tcm->tcm_parent,
1530 					 tca, &err, extack);
1531 		} else {
1532 			NL_SET_ERR_MSG(extack, "Cannot find ingress queue for specified device");
1533 			err = -ENOENT;
1534 		}
1535 	} else {
1536 		struct netdev_queue *dev_queue;
1537 
1538 		if (p && p->ops->cl_ops && p->ops->cl_ops->select_queue)
1539 			dev_queue = p->ops->cl_ops->select_queue(p, tcm);
1540 		else if (p)
1541 			dev_queue = p->dev_queue;
1542 		else
1543 			dev_queue = netdev_get_tx_queue(dev, 0);
1544 
1545 		q = qdisc_create(dev, dev_queue, p,
1546 				 tcm->tcm_parent, tcm->tcm_handle,
1547 				 tca, &err, extack);
1548 	}
1549 	if (q == NULL) {
1550 		if (err == -EAGAIN)
1551 			goto replay;
1552 		return err;
1553 	}
1554 
1555 graft:
1556 	err = qdisc_graft(dev, p, skb, n, clid, q, NULL, extack);
1557 	if (err) {
1558 		if (q)
1559 			qdisc_destroy(q);
1560 		return err;
1561 	}
1562 
1563 	return 0;
1564 }
1565 
1566 static int tc_dump_qdisc_root(struct Qdisc *root, struct sk_buff *skb,
1567 			      struct netlink_callback *cb,
1568 			      int *q_idx_p, int s_q_idx, bool recur,
1569 			      bool dump_invisible)
1570 {
1571 	int ret = 0, q_idx = *q_idx_p;
1572 	struct Qdisc *q;
1573 	int b;
1574 
1575 	if (!root)
1576 		return 0;
1577 
1578 	q = root;
1579 	if (q_idx < s_q_idx) {
1580 		q_idx++;
1581 	} else {
1582 		if (!tc_qdisc_dump_ignore(q, dump_invisible) &&
1583 		    tc_fill_qdisc(skb, q, q->parent, NETLINK_CB(cb->skb).portid,
1584 				  cb->nlh->nlmsg_seq, NLM_F_MULTI,
1585 				  RTM_NEWQDISC) <= 0)
1586 			goto done;
1587 		q_idx++;
1588 	}
1589 
1590 	/* If dumping singletons, there is no qdisc_dev(root) and the singleton
1591 	 * itself has already been dumped.
1592 	 *
1593 	 * If we've already dumped the top-level (ingress) qdisc above and the global
1594 	 * qdisc hashtable, we don't want to hit it again
1595 	 */
1596 	if (!qdisc_dev(root) || !recur)
1597 		goto out;
1598 
1599 	hash_for_each(qdisc_dev(root)->qdisc_hash, b, q, hash) {
1600 		if (q_idx < s_q_idx) {
1601 			q_idx++;
1602 			continue;
1603 		}
1604 		if (!tc_qdisc_dump_ignore(q, dump_invisible) &&
1605 		    tc_fill_qdisc(skb, q, q->parent, NETLINK_CB(cb->skb).portid,
1606 				  cb->nlh->nlmsg_seq, NLM_F_MULTI,
1607 				  RTM_NEWQDISC) <= 0)
1608 			goto done;
1609 		q_idx++;
1610 	}
1611 
1612 out:
1613 	*q_idx_p = q_idx;
1614 	return ret;
1615 done:
1616 	ret = -1;
1617 	goto out;
1618 }
1619 
1620 static int tc_dump_qdisc(struct sk_buff *skb, struct netlink_callback *cb)
1621 {
1622 	struct net *net = sock_net(skb->sk);
1623 	int idx, q_idx;
1624 	int s_idx, s_q_idx;
1625 	struct net_device *dev;
1626 	const struct nlmsghdr *nlh = cb->nlh;
1627 	struct nlattr *tca[TCA_MAX + 1];
1628 	int err;
1629 
1630 	s_idx = cb->args[0];
1631 	s_q_idx = q_idx = cb->args[1];
1632 
1633 	idx = 0;
1634 	ASSERT_RTNL();
1635 
1636 	err = nlmsg_parse(nlh, sizeof(struct tcmsg), tca, TCA_MAX, NULL, NULL);
1637 	if (err < 0)
1638 		return err;
1639 
1640 	for_each_netdev(net, dev) {
1641 		struct netdev_queue *dev_queue;
1642 
1643 		if (idx < s_idx)
1644 			goto cont;
1645 		if (idx > s_idx)
1646 			s_q_idx = 0;
1647 		q_idx = 0;
1648 
1649 		if (tc_dump_qdisc_root(dev->qdisc, skb, cb, &q_idx, s_q_idx,
1650 				       true, tca[TCA_DUMP_INVISIBLE]) < 0)
1651 			goto done;
1652 
1653 		dev_queue = dev_ingress_queue(dev);
1654 		if (dev_queue &&
1655 		    tc_dump_qdisc_root(dev_queue->qdisc_sleeping, skb, cb,
1656 				       &q_idx, s_q_idx, false,
1657 				       tca[TCA_DUMP_INVISIBLE]) < 0)
1658 			goto done;
1659 
1660 cont:
1661 		idx++;
1662 	}
1663 
1664 done:
1665 	cb->args[0] = idx;
1666 	cb->args[1] = q_idx;
1667 
1668 	return skb->len;
1669 }
1670 
1671 
1672 
1673 /************************************************
1674  *	Traffic classes manipulation.		*
1675  ************************************************/
1676 
1677 static int tc_fill_tclass(struct sk_buff *skb, struct Qdisc *q,
1678 			  unsigned long cl,
1679 			  u32 portid, u32 seq, u16 flags, int event)
1680 {
1681 	struct tcmsg *tcm;
1682 	struct nlmsghdr  *nlh;
1683 	unsigned char *b = skb_tail_pointer(skb);
1684 	struct gnet_dump d;
1685 	const struct Qdisc_class_ops *cl_ops = q->ops->cl_ops;
1686 
1687 	cond_resched();
1688 	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*tcm), flags);
1689 	if (!nlh)
1690 		goto out_nlmsg_trim;
1691 	tcm = nlmsg_data(nlh);
1692 	tcm->tcm_family = AF_UNSPEC;
1693 	tcm->tcm__pad1 = 0;
1694 	tcm->tcm__pad2 = 0;
1695 	tcm->tcm_ifindex = qdisc_dev(q)->ifindex;
1696 	tcm->tcm_parent = q->handle;
1697 	tcm->tcm_handle = q->handle;
1698 	tcm->tcm_info = 0;
1699 	if (nla_put_string(skb, TCA_KIND, q->ops->id))
1700 		goto nla_put_failure;
1701 	if (cl_ops->dump && cl_ops->dump(q, cl, skb, tcm) < 0)
1702 		goto nla_put_failure;
1703 
1704 	if (gnet_stats_start_copy_compat(skb, TCA_STATS2, TCA_STATS, TCA_XSTATS,
1705 					 NULL, &d, TCA_PAD) < 0)
1706 		goto nla_put_failure;
1707 
1708 	if (cl_ops->dump_stats && cl_ops->dump_stats(q, cl, &d) < 0)
1709 		goto nla_put_failure;
1710 
1711 	if (gnet_stats_finish_copy(&d) < 0)
1712 		goto nla_put_failure;
1713 
1714 	nlh->nlmsg_len = skb_tail_pointer(skb) - b;
1715 	return skb->len;
1716 
1717 out_nlmsg_trim:
1718 nla_put_failure:
1719 	nlmsg_trim(skb, b);
1720 	return -1;
1721 }
1722 
1723 static int tclass_notify(struct net *net, struct sk_buff *oskb,
1724 			 struct nlmsghdr *n, struct Qdisc *q,
1725 			 unsigned long cl, int event)
1726 {
1727 	struct sk_buff *skb;
1728 	u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
1729 
1730 	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
1731 	if (!skb)
1732 		return -ENOBUFS;
1733 
1734 	if (tc_fill_tclass(skb, q, cl, portid, n->nlmsg_seq, 0, event) < 0) {
1735 		kfree_skb(skb);
1736 		return -EINVAL;
1737 	}
1738 
1739 	return rtnetlink_send(skb, net, portid, RTNLGRP_TC,
1740 			      n->nlmsg_flags & NLM_F_ECHO);
1741 }
1742 
1743 static int tclass_del_notify(struct net *net,
1744 			     const struct Qdisc_class_ops *cops,
1745 			     struct sk_buff *oskb, struct nlmsghdr *n,
1746 			     struct Qdisc *q, unsigned long cl)
1747 {
1748 	u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
1749 	struct sk_buff *skb;
1750 	int err = 0;
1751 
1752 	if (!cops->delete)
1753 		return -EOPNOTSUPP;
1754 
1755 	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
1756 	if (!skb)
1757 		return -ENOBUFS;
1758 
1759 	if (tc_fill_tclass(skb, q, cl, portid, n->nlmsg_seq, 0,
1760 			   RTM_DELTCLASS) < 0) {
1761 		kfree_skb(skb);
1762 		return -EINVAL;
1763 	}
1764 
1765 	err = cops->delete(q, cl);
1766 	if (err) {
1767 		kfree_skb(skb);
1768 		return err;
1769 	}
1770 
1771 	return rtnetlink_send(skb, net, portid, RTNLGRP_TC,
1772 			      n->nlmsg_flags & NLM_F_ECHO);
1773 }
1774 
1775 #ifdef CONFIG_NET_CLS
1776 
1777 struct tcf_bind_args {
1778 	struct tcf_walker w;
1779 	u32 classid;
1780 	unsigned long cl;
1781 };
1782 
1783 static int tcf_node_bind(struct tcf_proto *tp, void *n, struct tcf_walker *arg)
1784 {
1785 	struct tcf_bind_args *a = (void *)arg;
1786 
1787 	if (tp->ops->bind_class) {
1788 		struct Qdisc *q = tcf_block_q(tp->chain->block);
1789 
1790 		sch_tree_lock(q);
1791 		tp->ops->bind_class(n, a->classid, a->cl);
1792 		sch_tree_unlock(q);
1793 	}
1794 	return 0;
1795 }
1796 
1797 static void tc_bind_tclass(struct Qdisc *q, u32 portid, u32 clid,
1798 			   unsigned long new_cl)
1799 {
1800 	const struct Qdisc_class_ops *cops = q->ops->cl_ops;
1801 	struct tcf_block *block;
1802 	struct tcf_chain *chain;
1803 	unsigned long cl;
1804 
1805 	cl = cops->find(q, portid);
1806 	if (!cl)
1807 		return;
1808 	block = cops->tcf_block(q, cl, NULL);
1809 	if (!block)
1810 		return;
1811 	list_for_each_entry(chain, &block->chain_list, list) {
1812 		struct tcf_proto *tp;
1813 
1814 		for (tp = rtnl_dereference(chain->filter_chain);
1815 		     tp; tp = rtnl_dereference(tp->next)) {
1816 			struct tcf_bind_args arg = {};
1817 
1818 			arg.w.fn = tcf_node_bind;
1819 			arg.classid = clid;
1820 			arg.cl = new_cl;
1821 			tp->ops->walk(tp, &arg.w);
1822 		}
1823 	}
1824 }
1825 
1826 #else
1827 
1828 static void tc_bind_tclass(struct Qdisc *q, u32 portid, u32 clid,
1829 			   unsigned long new_cl)
1830 {
1831 }
1832 
1833 #endif
1834 
1835 static int tc_ctl_tclass(struct sk_buff *skb, struct nlmsghdr *n,
1836 			 struct netlink_ext_ack *extack)
1837 {
1838 	struct net *net = sock_net(skb->sk);
1839 	struct tcmsg *tcm = nlmsg_data(n);
1840 	struct nlattr *tca[TCA_MAX + 1];
1841 	struct net_device *dev;
1842 	struct Qdisc *q = NULL;
1843 	const struct Qdisc_class_ops *cops;
1844 	unsigned long cl = 0;
1845 	unsigned long new_cl;
1846 	u32 portid;
1847 	u32 clid;
1848 	u32 qid;
1849 	int err;
1850 
1851 	if ((n->nlmsg_type != RTM_GETTCLASS) &&
1852 	    !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
1853 		return -EPERM;
1854 
1855 	err = nlmsg_parse(n, sizeof(*tcm), tca, TCA_MAX, NULL, extack);
1856 	if (err < 0)
1857 		return err;
1858 
1859 	dev = __dev_get_by_index(net, tcm->tcm_ifindex);
1860 	if (!dev)
1861 		return -ENODEV;
1862 
1863 	/*
1864 	   parent == TC_H_UNSPEC - unspecified parent.
1865 	   parent == TC_H_ROOT   - class is root, which has no parent.
1866 	   parent == X:0	 - parent is root class.
1867 	   parent == X:Y	 - parent is a node in hierarchy.
1868 	   parent == 0:Y	 - parent is X:Y, where X:0 is qdisc.
1869 
1870 	   handle == 0:0	 - generate handle from kernel pool.
1871 	   handle == 0:Y	 - class is X:Y, where X:0 is qdisc.
1872 	   handle == X:Y	 - clear.
1873 	   handle == X:0	 - root class.
1874 	 */
1875 
1876 	/* Step 1. Determine qdisc handle X:0 */
1877 
1878 	portid = tcm->tcm_parent;
1879 	clid = tcm->tcm_handle;
1880 	qid = TC_H_MAJ(clid);
1881 
1882 	if (portid != TC_H_ROOT) {
1883 		u32 qid1 = TC_H_MAJ(portid);
1884 
1885 		if (qid && qid1) {
1886 			/* If both majors are known, they must be identical. */
1887 			if (qid != qid1)
1888 				return -EINVAL;
1889 		} else if (qid1) {
1890 			qid = qid1;
1891 		} else if (qid == 0)
1892 			qid = dev->qdisc->handle;
1893 
1894 		/* Now qid is genuine qdisc handle consistent
1895 		 * both with parent and child.
1896 		 *
1897 		 * TC_H_MAJ(portid) still may be unspecified, complete it now.
1898 		 */
1899 		if (portid)
1900 			portid = TC_H_MAKE(qid, portid);
1901 	} else {
1902 		if (qid == 0)
1903 			qid = dev->qdisc->handle;
1904 	}
1905 
1906 	/* OK. Locate qdisc */
1907 	q = qdisc_lookup(dev, qid);
1908 	if (!q)
1909 		return -ENOENT;
1910 
1911 	/* An check that it supports classes */
1912 	cops = q->ops->cl_ops;
1913 	if (cops == NULL)
1914 		return -EINVAL;
1915 
1916 	/* Now try to get class */
1917 	if (clid == 0) {
1918 		if (portid == TC_H_ROOT)
1919 			clid = qid;
1920 	} else
1921 		clid = TC_H_MAKE(qid, clid);
1922 
1923 	if (clid)
1924 		cl = cops->find(q, clid);
1925 
1926 	if (cl == 0) {
1927 		err = -ENOENT;
1928 		if (n->nlmsg_type != RTM_NEWTCLASS ||
1929 		    !(n->nlmsg_flags & NLM_F_CREATE))
1930 			goto out;
1931 	} else {
1932 		switch (n->nlmsg_type) {
1933 		case RTM_NEWTCLASS:
1934 			err = -EEXIST;
1935 			if (n->nlmsg_flags & NLM_F_EXCL)
1936 				goto out;
1937 			break;
1938 		case RTM_DELTCLASS:
1939 			err = tclass_del_notify(net, cops, skb, n, q, cl);
1940 			/* Unbind the class with flilters with 0 */
1941 			tc_bind_tclass(q, portid, clid, 0);
1942 			goto out;
1943 		case RTM_GETTCLASS:
1944 			err = tclass_notify(net, skb, n, q, cl, RTM_NEWTCLASS);
1945 			goto out;
1946 		default:
1947 			err = -EINVAL;
1948 			goto out;
1949 		}
1950 	}
1951 
1952 	if (tca[TCA_INGRESS_BLOCK] || tca[TCA_EGRESS_BLOCK]) {
1953 		NL_SET_ERR_MSG(extack, "Shared blocks are not supported for classes");
1954 		return -EOPNOTSUPP;
1955 	}
1956 
1957 	new_cl = cl;
1958 	err = -EOPNOTSUPP;
1959 	if (cops->change)
1960 		err = cops->change(q, clid, portid, tca, &new_cl, extack);
1961 	if (err == 0) {
1962 		tclass_notify(net, skb, n, q, new_cl, RTM_NEWTCLASS);
1963 		/* We just create a new class, need to do reverse binding. */
1964 		if (cl != new_cl)
1965 			tc_bind_tclass(q, portid, clid, new_cl);
1966 	}
1967 out:
1968 	return err;
1969 }
1970 
1971 struct qdisc_dump_args {
1972 	struct qdisc_walker	w;
1973 	struct sk_buff		*skb;
1974 	struct netlink_callback	*cb;
1975 };
1976 
1977 static int qdisc_class_dump(struct Qdisc *q, unsigned long cl,
1978 			    struct qdisc_walker *arg)
1979 {
1980 	struct qdisc_dump_args *a = (struct qdisc_dump_args *)arg;
1981 
1982 	return tc_fill_tclass(a->skb, q, cl, NETLINK_CB(a->cb->skb).portid,
1983 			      a->cb->nlh->nlmsg_seq, NLM_F_MULTI,
1984 			      RTM_NEWTCLASS);
1985 }
1986 
1987 static int tc_dump_tclass_qdisc(struct Qdisc *q, struct sk_buff *skb,
1988 				struct tcmsg *tcm, struct netlink_callback *cb,
1989 				int *t_p, int s_t)
1990 {
1991 	struct qdisc_dump_args arg;
1992 
1993 	if (tc_qdisc_dump_ignore(q, false) ||
1994 	    *t_p < s_t || !q->ops->cl_ops ||
1995 	    (tcm->tcm_parent &&
1996 	     TC_H_MAJ(tcm->tcm_parent) != q->handle)) {
1997 		(*t_p)++;
1998 		return 0;
1999 	}
2000 	if (*t_p > s_t)
2001 		memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0]));
2002 	arg.w.fn = qdisc_class_dump;
2003 	arg.skb = skb;
2004 	arg.cb = cb;
2005 	arg.w.stop  = 0;
2006 	arg.w.skip = cb->args[1];
2007 	arg.w.count = 0;
2008 	q->ops->cl_ops->walk(q, &arg.w);
2009 	cb->args[1] = arg.w.count;
2010 	if (arg.w.stop)
2011 		return -1;
2012 	(*t_p)++;
2013 	return 0;
2014 }
2015 
2016 static int tc_dump_tclass_root(struct Qdisc *root, struct sk_buff *skb,
2017 			       struct tcmsg *tcm, struct netlink_callback *cb,
2018 			       int *t_p, int s_t)
2019 {
2020 	struct Qdisc *q;
2021 	int b;
2022 
2023 	if (!root)
2024 		return 0;
2025 
2026 	if (tc_dump_tclass_qdisc(root, skb, tcm, cb, t_p, s_t) < 0)
2027 		return -1;
2028 
2029 	if (!qdisc_dev(root))
2030 		return 0;
2031 
2032 	if (tcm->tcm_parent) {
2033 		q = qdisc_match_from_root(root, TC_H_MAJ(tcm->tcm_parent));
2034 		if (q && tc_dump_tclass_qdisc(q, skb, tcm, cb, t_p, s_t) < 0)
2035 			return -1;
2036 		return 0;
2037 	}
2038 	hash_for_each(qdisc_dev(root)->qdisc_hash, b, q, hash) {
2039 		if (tc_dump_tclass_qdisc(q, skb, tcm, cb, t_p, s_t) < 0)
2040 			return -1;
2041 	}
2042 
2043 	return 0;
2044 }
2045 
2046 static int tc_dump_tclass(struct sk_buff *skb, struct netlink_callback *cb)
2047 {
2048 	struct tcmsg *tcm = nlmsg_data(cb->nlh);
2049 	struct net *net = sock_net(skb->sk);
2050 	struct netdev_queue *dev_queue;
2051 	struct net_device *dev;
2052 	int t, s_t;
2053 
2054 	if (nlmsg_len(cb->nlh) < sizeof(*tcm))
2055 		return 0;
2056 	dev = dev_get_by_index(net, tcm->tcm_ifindex);
2057 	if (!dev)
2058 		return 0;
2059 
2060 	s_t = cb->args[0];
2061 	t = 0;
2062 
2063 	if (tc_dump_tclass_root(dev->qdisc, skb, tcm, cb, &t, s_t) < 0)
2064 		goto done;
2065 
2066 	dev_queue = dev_ingress_queue(dev);
2067 	if (dev_queue &&
2068 	    tc_dump_tclass_root(dev_queue->qdisc_sleeping, skb, tcm, cb,
2069 				&t, s_t) < 0)
2070 		goto done;
2071 
2072 done:
2073 	cb->args[0] = t;
2074 
2075 	dev_put(dev);
2076 	return skb->len;
2077 }
2078 
2079 #ifdef CONFIG_PROC_FS
2080 static int psched_show(struct seq_file *seq, void *v)
2081 {
2082 	seq_printf(seq, "%08x %08x %08x %08x\n",
2083 		   (u32)NSEC_PER_USEC, (u32)PSCHED_TICKS2NS(1),
2084 		   1000000,
2085 		   (u32)NSEC_PER_SEC / hrtimer_resolution);
2086 
2087 	return 0;
2088 }
2089 
2090 static int psched_open(struct inode *inode, struct file *file)
2091 {
2092 	return single_open(file, psched_show, NULL);
2093 }
2094 
2095 static const struct file_operations psched_fops = {
2096 	.open = psched_open,
2097 	.read  = seq_read,
2098 	.llseek = seq_lseek,
2099 	.release = single_release,
2100 };
2101 
2102 static int __net_init psched_net_init(struct net *net)
2103 {
2104 	struct proc_dir_entry *e;
2105 
2106 	e = proc_create("psched", 0, net->proc_net, &psched_fops);
2107 	if (e == NULL)
2108 		return -ENOMEM;
2109 
2110 	return 0;
2111 }
2112 
2113 static void __net_exit psched_net_exit(struct net *net)
2114 {
2115 	remove_proc_entry("psched", net->proc_net);
2116 }
2117 #else
2118 static int __net_init psched_net_init(struct net *net)
2119 {
2120 	return 0;
2121 }
2122 
2123 static void __net_exit psched_net_exit(struct net *net)
2124 {
2125 }
2126 #endif
2127 
2128 static struct pernet_operations psched_net_ops = {
2129 	.init = psched_net_init,
2130 	.exit = psched_net_exit,
2131 };
2132 
2133 static int __init pktsched_init(void)
2134 {
2135 	int err;
2136 
2137 	err = register_pernet_subsys(&psched_net_ops);
2138 	if (err) {
2139 		pr_err("pktsched_init: "
2140 		       "cannot initialize per netns operations\n");
2141 		return err;
2142 	}
2143 
2144 	register_qdisc(&pfifo_fast_ops);
2145 	register_qdisc(&pfifo_qdisc_ops);
2146 	register_qdisc(&bfifo_qdisc_ops);
2147 	register_qdisc(&pfifo_head_drop_qdisc_ops);
2148 	register_qdisc(&mq_qdisc_ops);
2149 	register_qdisc(&noqueue_qdisc_ops);
2150 
2151 	rtnl_register(PF_UNSPEC, RTM_NEWQDISC, tc_modify_qdisc, NULL, 0);
2152 	rtnl_register(PF_UNSPEC, RTM_DELQDISC, tc_get_qdisc, NULL, 0);
2153 	rtnl_register(PF_UNSPEC, RTM_GETQDISC, tc_get_qdisc, tc_dump_qdisc,
2154 		      0);
2155 	rtnl_register(PF_UNSPEC, RTM_NEWTCLASS, tc_ctl_tclass, NULL, 0);
2156 	rtnl_register(PF_UNSPEC, RTM_DELTCLASS, tc_ctl_tclass, NULL, 0);
2157 	rtnl_register(PF_UNSPEC, RTM_GETTCLASS, tc_ctl_tclass, tc_dump_tclass,
2158 		      0);
2159 
2160 	return 0;
2161 }
2162 
2163 subsys_initcall(pktsched_init);
2164