1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * net/sched/sch_htb.c Hierarchical token bucket, feed tree version
5 * Authors: Martin Devera, <devik@cdi.cz>
7 * Credits (in time order) for older HTB versions:
8 * Stef Coene <stef.coene@docum.org>
9 * HTB support at LARTC mailing list
10 * Ondrej Kraus, <krauso@barr.cz>
11 * found missing INIT_QDISC(htb)
12 * Vladimir Smelhaus, Aamer Akhter, Bert Hubert
13 * helped a lot to locate nasty class stall bug
14 * Andi Kleen, Jamal Hadi, Bert Hubert
15 * code review and helpful comments on shaping
16 * Tomasz Wrona, <tw@eter.tym.pl>
17 * created test case so that I was able to fix nasty bug
19 * spotted bug in dequeue code and helped with fix
21 * fixed requeue routine
22 * and many others. thanks.
24 #include <linux/module.h>
25 #include <linux/moduleparam.h>
26 #include <linux/types.h>
27 #include <linux/kernel.h>
28 #include <linux/string.h>
29 #include <linux/errno.h>
30 #include <linux/skbuff.h>
31 #include <linux/list.h>
32 #include <linux/compiler.h>
33 #include <linux/rbtree.h>
34 #include <linux/workqueue.h>
35 #include <linux/slab.h>
36 #include <net/netlink.h>
37 #include <net/sch_generic.h>
38 #include <net/pkt_sched.h>
39 #include <net/pkt_cls.h>
43 ========================================================================
44 HTB is like TBF with multiple classes. It is also similar to CBQ because
45 it allows to assign priority to each class in hierarchy.
46 In fact it is another implementation of Floyd's formal sharing.
49 Each class is assigned level. Leaf has ALWAYS level 0 and root
50 classes have level TC_HTB_MAXDEPTH-1. Interior nodes has level
51 one less than their parent.
54 static int htb_hysteresis __read_mostly = 0; /* whether to use mode hysteresis for speedup */
55 #define HTB_VER 0x30011 /* major must be matched with number suplied by TC as version */
57 #if HTB_VER >> 16 != TC_HTB_PROTOVER
58 #error "Mismatched sch_htb.c and pkt_sch.h"
61 /* Module parameter and sysfs export */
62 module_param (htb_hysteresis, int, 0640);
63 MODULE_PARM_DESC(htb_hysteresis, "Hysteresis mode, less CPU load, less accurate");
65 static int htb_rate_est = 0; /* htb classes have a default rate estimator */
66 module_param(htb_rate_est, int, 0640);
67 MODULE_PARM_DESC(htb_rate_est, "setup a default rate estimator (4sec 16sec) for htb classes");
69 /* used internaly to keep status of single class */
71 HTB_CANT_SEND, /* class can't send and can't borrow */
72 HTB_MAY_BORROW, /* class can't send but may borrow */
73 HTB_CAN_SEND /* class can send */
82 /* When class changes from state 1->2 and disconnects from
83 * parent's feed then we lost ptr value and start from the
84 * first child again. Here we store classid of the
85 * last valid ptr (used when ptr is NULL).
90 /* interior & leaf nodes; props specific to leaves are marked L:
91 * To reduce false sharing, place mostly read fields at beginning,
92 * and mostly written ones at the end.
95 struct Qdisc_class_common common;
96 struct psched_ratecfg rate;
97 struct psched_ratecfg ceil;
98 s64 buffer, cbuffer;/* token bucket depth/rate */
99 s64 mbuffer; /* max wait time */
100 u32 prio; /* these two are used only by leaves... */
101 int quantum; /* but stored for parent-to-leaf return */
103 struct tcf_proto __rcu *filter_list; /* class attached filters */
104 struct tcf_block *block;
107 int level; /* our level (see above) */
108 unsigned int children;
109 struct htb_class *parent; /* parent class */
111 struct net_rate_estimator __rcu *rate_est;
114 * Written often fields
116 struct gnet_stats_basic_packed bstats;
117 struct tc_htb_xstats xstats; /* our special stats */
119 /* token bucket parameters */
120 s64 tokens, ctokens;/* current number of tokens */
121 s64 t_c; /* checkpoint time */
124 struct htb_class_leaf {
125 int deficit[TC_HTB_MAXDEPTH];
128 struct htb_class_inner {
129 struct htb_prio clprio[TC_HTB_NUMPRIO];
134 int prio_activity; /* for which prios are we active */
135 enum htb_cmode cmode; /* current mode of the class */
136 struct rb_node pq_node; /* node for event queue */
137 struct rb_node node[TC_HTB_NUMPRIO]; /* node for self or feed tree */
139 unsigned int drops ____cacheline_aligned_in_smp;
140 unsigned int overlimits;
144 struct rb_root wait_pq;
145 struct htb_prio hprio[TC_HTB_NUMPRIO];
149 struct Qdisc_class_hash clhash;
150 int defcls; /* class where unclassified flows go to */
151 int rate2quantum; /* quant = rate / rate2quantum */
153 /* filters for qdisc itself */
154 struct tcf_proto __rcu *filter_list;
155 struct tcf_block *block;
157 #define HTB_WARN_TOOMANYEVENTS 0x1
158 unsigned int warned; /* only one warning */
160 struct work_struct work;
162 /* non shaped skbs; let them go directly thru */
163 struct qdisc_skb_head direct_queue;
167 struct qdisc_watchdog watchdog;
169 s64 now; /* cached dequeue time */
171 /* time of nearest event per level (row) */
172 s64 near_ev_cache[TC_HTB_MAXDEPTH];
174 int row_mask[TC_HTB_MAXDEPTH];
176 struct htb_level hlevel[TC_HTB_MAXDEPTH];
179 /* find class in global hash table using given handle */
180 static inline struct htb_class *htb_find(u32 handle, struct Qdisc *sch)
182 struct htb_sched *q = qdisc_priv(sch);
183 struct Qdisc_class_common *clc;
185 clc = qdisc_class_find(&q->clhash, handle);
188 return container_of(clc, struct htb_class, common);
191 static unsigned long htb_search(struct Qdisc *sch, u32 handle)
193 return (unsigned long)htb_find(handle, sch);
196 * htb_classify - classify a packet into class
198 * It returns NULL if the packet should be dropped or -1 if the packet
199 * should be passed directly thru. In all other cases leaf class is returned.
200 * We allow direct class selection by classid in priority. The we examine
201 * filters in qdisc and in inner nodes (if higher filter points to the inner
202 * node). If we end up with classid MAJOR:0 we enqueue the skb into special
203 * internal fifo (direct). These packets then go directly thru. If we still
204 * have no valid leaf we try to use MAJOR:default leaf. It still unsuccessful
205 * then finish and return direct queue.
207 #define HTB_DIRECT ((struct htb_class *)-1L)
209 static struct htb_class *htb_classify(struct sk_buff *skb, struct Qdisc *sch,
212 struct htb_sched *q = qdisc_priv(sch);
213 struct htb_class *cl;
214 struct tcf_result res;
215 struct tcf_proto *tcf;
218 /* allow to select class by setting skb->priority to valid classid;
219 * note that nfmark can be used too by attaching filter fw with no
222 if (skb->priority == sch->handle)
223 return HTB_DIRECT; /* X:0 (direct flow) selected */
224 cl = htb_find(skb->priority, sch);
228 /* Start with inner filter chain if a non-leaf class is selected */
229 tcf = rcu_dereference_bh(cl->filter_list);
231 tcf = rcu_dereference_bh(q->filter_list);
234 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
235 while (tcf && (result = tcf_classify(skb, tcf, &res, false)) >= 0) {
236 #ifdef CONFIG_NET_CLS_ACT
241 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
247 cl = (void *)res.class;
249 if (res.classid == sch->handle)
250 return HTB_DIRECT; /* X:0 (direct flow) */
251 cl = htb_find(res.classid, sch);
253 break; /* filter selected invalid classid */
256 return cl; /* we hit leaf; return it */
258 /* we have got inner class; apply inner filter chain */
259 tcf = rcu_dereference_bh(cl->filter_list);
261 /* classification failed; try to use default class */
262 cl = htb_find(TC_H_MAKE(TC_H_MAJ(sch->handle), q->defcls), sch);
263 if (!cl || cl->level)
264 return HTB_DIRECT; /* bad default .. this is safe bet */
269 * htb_add_to_id_tree - adds class to the round robin list
271 * Routine adds class to the list (actually tree) sorted by classid.
272 * Make sure that class is not already on such list for given prio.
274 static void htb_add_to_id_tree(struct rb_root *root,
275 struct htb_class *cl, int prio)
277 struct rb_node **p = &root->rb_node, *parent = NULL;
282 c = rb_entry(parent, struct htb_class, node[prio]);
284 if (cl->common.classid > c->common.classid)
285 p = &parent->rb_right;
287 p = &parent->rb_left;
289 rb_link_node(&cl->node[prio], parent, p);
290 rb_insert_color(&cl->node[prio], root);
294 * htb_add_to_wait_tree - adds class to the event queue with delay
296 * The class is added to priority event queue to indicate that class will
297 * change its mode in cl->pq_key microseconds. Make sure that class is not
298 * already in the queue.
300 static void htb_add_to_wait_tree(struct htb_sched *q,
301 struct htb_class *cl, s64 delay)
303 struct rb_node **p = &q->hlevel[cl->level].wait_pq.rb_node, *parent = NULL;
305 cl->pq_key = q->now + delay;
306 if (cl->pq_key == q->now)
309 /* update the nearest event cache */
310 if (q->near_ev_cache[cl->level] > cl->pq_key)
311 q->near_ev_cache[cl->level] = cl->pq_key;
316 c = rb_entry(parent, struct htb_class, pq_node);
317 if (cl->pq_key >= c->pq_key)
318 p = &parent->rb_right;
320 p = &parent->rb_left;
322 rb_link_node(&cl->pq_node, parent, p);
323 rb_insert_color(&cl->pq_node, &q->hlevel[cl->level].wait_pq);
327 * htb_next_rb_node - finds next node in binary tree
329 * When we are past last key we return NULL.
330 * Average complexity is 2 steps per call.
332 static inline void htb_next_rb_node(struct rb_node **n)
338 * htb_add_class_to_row - add class to its row
340 * The class is added to row at priorities marked in mask.
341 * It does nothing if mask == 0.
343 static inline void htb_add_class_to_row(struct htb_sched *q,
344 struct htb_class *cl, int mask)
346 q->row_mask[cl->level] |= mask;
348 int prio = ffz(~mask);
349 mask &= ~(1 << prio);
350 htb_add_to_id_tree(&q->hlevel[cl->level].hprio[prio].row, cl, prio);
354 /* If this triggers, it is a bug in this code, but it need not be fatal */
355 static void htb_safe_rb_erase(struct rb_node *rb, struct rb_root *root)
357 if (RB_EMPTY_NODE(rb)) {
367 * htb_remove_class_from_row - removes class from its row
369 * The class is removed from row at priorities marked in mask.
370 * It does nothing if mask == 0.
372 static inline void htb_remove_class_from_row(struct htb_sched *q,
373 struct htb_class *cl, int mask)
376 struct htb_level *hlevel = &q->hlevel[cl->level];
379 int prio = ffz(~mask);
380 struct htb_prio *hprio = &hlevel->hprio[prio];
382 mask &= ~(1 << prio);
383 if (hprio->ptr == cl->node + prio)
384 htb_next_rb_node(&hprio->ptr);
386 htb_safe_rb_erase(cl->node + prio, &hprio->row);
387 if (!hprio->row.rb_node)
390 q->row_mask[cl->level] &= ~m;
394 * htb_activate_prios - creates active classe's feed chain
396 * The class is connected to ancestors and/or appropriate rows
397 * for priorities it is participating on. cl->cmode must be new
398 * (activated) mode. It does nothing if cl->prio_activity == 0.
400 static void htb_activate_prios(struct htb_sched *q, struct htb_class *cl)
402 struct htb_class *p = cl->parent;
403 long m, mask = cl->prio_activity;
405 while (cl->cmode == HTB_MAY_BORROW && p && mask) {
408 unsigned int prio = ffz(~m);
410 if (WARN_ON_ONCE(prio >= ARRAY_SIZE(p->inner.clprio)))
414 if (p->inner.clprio[prio].feed.rb_node)
415 /* parent already has its feed in use so that
416 * reset bit in mask as parent is already ok
418 mask &= ~(1 << prio);
420 htb_add_to_id_tree(&p->inner.clprio[prio].feed, cl, prio);
422 p->prio_activity |= mask;
427 if (cl->cmode == HTB_CAN_SEND && mask)
428 htb_add_class_to_row(q, cl, mask);
432 * htb_deactivate_prios - remove class from feed chain
434 * cl->cmode must represent old mode (before deactivation). It does
435 * nothing if cl->prio_activity == 0. Class is removed from all feed
438 static void htb_deactivate_prios(struct htb_sched *q, struct htb_class *cl)
440 struct htb_class *p = cl->parent;
441 long m, mask = cl->prio_activity;
443 while (cl->cmode == HTB_MAY_BORROW && p && mask) {
450 if (p->inner.clprio[prio].ptr == cl->node + prio) {
451 /* we are removing child which is pointed to from
452 * parent feed - forget the pointer but remember
455 p->inner.clprio[prio].last_ptr_id = cl->common.classid;
456 p->inner.clprio[prio].ptr = NULL;
459 htb_safe_rb_erase(cl->node + prio,
460 &p->inner.clprio[prio].feed);
462 if (!p->inner.clprio[prio].feed.rb_node)
466 p->prio_activity &= ~mask;
471 if (cl->cmode == HTB_CAN_SEND && mask)
472 htb_remove_class_from_row(q, cl, mask);
475 static inline s64 htb_lowater(const struct htb_class *cl)
478 return cl->cmode != HTB_CANT_SEND ? -cl->cbuffer : 0;
482 static inline s64 htb_hiwater(const struct htb_class *cl)
485 return cl->cmode == HTB_CAN_SEND ? -cl->buffer : 0;
492 * htb_class_mode - computes and returns current class mode
494 * It computes cl's mode at time cl->t_c+diff and returns it. If mode
495 * is not HTB_CAN_SEND then cl->pq_key is updated to time difference
496 * from now to time when cl will change its state.
497 * Also it is worth to note that class mode doesn't change simply
498 * at cl->{c,}tokens == 0 but there can rather be hysteresis of
499 * 0 .. -cl->{c,}buffer range. It is meant to limit number of
500 * mode transitions per time unit. The speed gain is about 1/6.
502 static inline enum htb_cmode
503 htb_class_mode(struct htb_class *cl, s64 *diff)
507 if ((toks = (cl->ctokens + *diff)) < htb_lowater(cl)) {
509 return HTB_CANT_SEND;
512 if ((toks = (cl->tokens + *diff)) >= htb_hiwater(cl))
516 return HTB_MAY_BORROW;
520 * htb_change_class_mode - changes classe's mode
522 * This should be the only way how to change classe's mode under normal
523 * cirsumstances. Routine will update feed lists linkage, change mode
524 * and add class to the wait event queue if appropriate. New mode should
525 * be different from old one and cl->pq_key has to be valid if changing
526 * to mode other than HTB_CAN_SEND (see htb_add_to_wait_tree).
529 htb_change_class_mode(struct htb_sched *q, struct htb_class *cl, s64 *diff)
531 enum htb_cmode new_mode = htb_class_mode(cl, diff);
533 if (new_mode == cl->cmode)
536 if (new_mode == HTB_CANT_SEND) {
541 if (cl->prio_activity) { /* not necessary: speed optimization */
542 if (cl->cmode != HTB_CANT_SEND)
543 htb_deactivate_prios(q, cl);
544 cl->cmode = new_mode;
545 if (new_mode != HTB_CANT_SEND)
546 htb_activate_prios(q, cl);
548 cl->cmode = new_mode;
552 * htb_activate - inserts leaf cl into appropriate active feeds
554 * Routine learns (new) priority of leaf and activates feed chain
555 * for the prio. It can be called on already active leaf safely.
556 * It also adds leaf into droplist.
558 static inline void htb_activate(struct htb_sched *q, struct htb_class *cl)
560 WARN_ON(cl->level || !cl->leaf.q || !cl->leaf.q->q.qlen);
562 if (!cl->prio_activity) {
563 cl->prio_activity = 1 << cl->prio;
564 htb_activate_prios(q, cl);
569 * htb_deactivate - remove leaf cl from active feeds
571 * Make sure that leaf is active. In the other words it can't be called
572 * with non-active leaf. It also removes class from the drop list.
574 static inline void htb_deactivate(struct htb_sched *q, struct htb_class *cl)
576 WARN_ON(!cl->prio_activity);
578 htb_deactivate_prios(q, cl);
579 cl->prio_activity = 0;
582 static int htb_enqueue(struct sk_buff *skb, struct Qdisc *sch,
583 struct sk_buff **to_free)
586 unsigned int len = qdisc_pkt_len(skb);
587 struct htb_sched *q = qdisc_priv(sch);
588 struct htb_class *cl = htb_classify(skb, sch, &ret);
590 if (cl == HTB_DIRECT) {
591 /* enqueue to helper queue */
592 if (q->direct_queue.qlen < q->direct_qlen) {
593 __qdisc_enqueue_tail(skb, &q->direct_queue);
596 return qdisc_drop(skb, sch, to_free);
598 #ifdef CONFIG_NET_CLS_ACT
600 if (ret & __NET_XMIT_BYPASS)
601 qdisc_qstats_drop(sch);
602 __qdisc_drop(skb, to_free);
605 } else if ((ret = qdisc_enqueue(skb, cl->leaf.q,
606 to_free)) != NET_XMIT_SUCCESS) {
607 if (net_xmit_drop_count(ret)) {
608 qdisc_qstats_drop(sch);
616 sch->qstats.backlog += len;
618 return NET_XMIT_SUCCESS;
621 static inline void htb_accnt_tokens(struct htb_class *cl, int bytes, s64 diff)
623 s64 toks = diff + cl->tokens;
625 if (toks > cl->buffer)
627 toks -= (s64) psched_l2t_ns(&cl->rate, bytes);
628 if (toks <= -cl->mbuffer)
629 toks = 1 - cl->mbuffer;
634 static inline void htb_accnt_ctokens(struct htb_class *cl, int bytes, s64 diff)
636 s64 toks = diff + cl->ctokens;
638 if (toks > cl->cbuffer)
640 toks -= (s64) psched_l2t_ns(&cl->ceil, bytes);
641 if (toks <= -cl->mbuffer)
642 toks = 1 - cl->mbuffer;
648 * htb_charge_class - charges amount "bytes" to leaf and ancestors
650 * Routine assumes that packet "bytes" long was dequeued from leaf cl
651 * borrowing from "level". It accounts bytes to ceil leaky bucket for
652 * leaf and all ancestors and to rate bucket for ancestors at levels
653 * "level" and higher. It also handles possible change of mode resulting
654 * from the update. Note that mode can also increase here (MAY_BORROW to
655 * CAN_SEND) because we can use more precise clock that event queue here.
656 * In such case we remove class from event queue first.
658 static void htb_charge_class(struct htb_sched *q, struct htb_class *cl,
659 int level, struct sk_buff *skb)
661 int bytes = qdisc_pkt_len(skb);
662 enum htb_cmode old_mode;
666 diff = min_t(s64, q->now - cl->t_c, cl->mbuffer);
667 if (cl->level >= level) {
668 if (cl->level == level)
670 htb_accnt_tokens(cl, bytes, diff);
672 cl->xstats.borrows++;
673 cl->tokens += diff; /* we moved t_c; update tokens */
675 htb_accnt_ctokens(cl, bytes, diff);
678 old_mode = cl->cmode;
680 htb_change_class_mode(q, cl, &diff);
681 if (old_mode != cl->cmode) {
682 if (old_mode != HTB_CAN_SEND)
683 htb_safe_rb_erase(&cl->pq_node, &q->hlevel[cl->level].wait_pq);
684 if (cl->cmode != HTB_CAN_SEND)
685 htb_add_to_wait_tree(q, cl, diff);
688 /* update basic stats except for leaves which are already updated */
690 bstats_update(&cl->bstats, skb);
697 * htb_do_events - make mode changes to classes at the level
699 * Scans event queue for pending events and applies them. Returns time of
700 * next pending event (0 for no event in pq, q->now for too many events).
701 * Note: Applied are events whose have cl->pq_key <= q->now.
703 static s64 htb_do_events(struct htb_sched *q, const int level,
706 /* don't run for longer than 2 jiffies; 2 is used instead of
707 * 1 to simplify things when jiffy is going to be incremented
710 unsigned long stop_at = start + 2;
711 struct rb_root *wait_pq = &q->hlevel[level].wait_pq;
713 while (time_before(jiffies, stop_at)) {
714 struct htb_class *cl;
716 struct rb_node *p = rb_first(wait_pq);
721 cl = rb_entry(p, struct htb_class, pq_node);
722 if (cl->pq_key > q->now)
725 htb_safe_rb_erase(p, wait_pq);
726 diff = min_t(s64, q->now - cl->t_c, cl->mbuffer);
727 htb_change_class_mode(q, cl, &diff);
728 if (cl->cmode != HTB_CAN_SEND)
729 htb_add_to_wait_tree(q, cl, diff);
732 /* too much load - let's continue after a break for scheduling */
733 if (!(q->warned & HTB_WARN_TOOMANYEVENTS)) {
734 pr_warn("htb: too many events!\n");
735 q->warned |= HTB_WARN_TOOMANYEVENTS;
741 /* Returns class->node+prio from id-tree where classe's id is >= id. NULL
742 * is no such one exists.
744 static struct rb_node *htb_id_find_next_upper(int prio, struct rb_node *n,
747 struct rb_node *r = NULL;
749 struct htb_class *cl =
750 rb_entry(n, struct htb_class, node[prio]);
752 if (id > cl->common.classid) {
754 } else if (id < cl->common.classid) {
765 * htb_lookup_leaf - returns next leaf class in DRR order
767 * Find leaf where current feed pointers points to.
769 static struct htb_class *htb_lookup_leaf(struct htb_prio *hprio, const int prio)
773 struct rb_node *root;
774 struct rb_node **pptr;
776 } stk[TC_HTB_MAXDEPTH], *sp = stk;
778 BUG_ON(!hprio->row.rb_node);
779 sp->root = hprio->row.rb_node;
780 sp->pptr = &hprio->ptr;
781 sp->pid = &hprio->last_ptr_id;
783 for (i = 0; i < 65535; i++) {
784 if (!*sp->pptr && *sp->pid) {
785 /* ptr was invalidated but id is valid - try to recover
786 * the original or next ptr
789 htb_id_find_next_upper(prio, sp->root, *sp->pid);
791 *sp->pid = 0; /* ptr is valid now so that remove this hint as it
792 * can become out of date quickly
794 if (!*sp->pptr) { /* we are at right end; rewind & go up */
795 *sp->pptr = sp->root;
796 while ((*sp->pptr)->rb_left)
797 *sp->pptr = (*sp->pptr)->rb_left;
804 htb_next_rb_node(sp->pptr);
807 struct htb_class *cl;
808 struct htb_prio *clp;
810 cl = rb_entry(*sp->pptr, struct htb_class, node[prio]);
813 clp = &cl->inner.clprio[prio];
814 (++sp)->root = clp->feed.rb_node;
815 sp->pptr = &clp->ptr;
816 sp->pid = &clp->last_ptr_id;
823 /* dequeues packet at given priority and level; call only if
824 * you are sure that there is active class at prio/level
826 static struct sk_buff *htb_dequeue_tree(struct htb_sched *q, const int prio,
829 struct sk_buff *skb = NULL;
830 struct htb_class *cl, *start;
831 struct htb_level *hlevel = &q->hlevel[level];
832 struct htb_prio *hprio = &hlevel->hprio[prio];
834 /* look initial class up in the row */
835 start = cl = htb_lookup_leaf(hprio, prio);
842 /* class can be empty - it is unlikely but can be true if leaf
843 * qdisc drops packets in enqueue routine or if someone used
844 * graft operation on the leaf since last dequeue;
845 * simply deactivate and skip such class
847 if (unlikely(cl->leaf.q->q.qlen == 0)) {
848 struct htb_class *next;
849 htb_deactivate(q, cl);
851 /* row/level might become empty */
852 if ((q->row_mask[level] & (1 << prio)) == 0)
855 next = htb_lookup_leaf(hprio, prio);
857 if (cl == start) /* fix start if we just deleted it */
863 skb = cl->leaf.q->dequeue(cl->leaf.q);
864 if (likely(skb != NULL))
867 qdisc_warn_nonwc("htb", cl->leaf.q);
868 htb_next_rb_node(level ? &cl->parent->inner.clprio[prio].ptr:
869 &q->hlevel[0].hprio[prio].ptr);
870 cl = htb_lookup_leaf(hprio, prio);
872 } while (cl != start);
874 if (likely(skb != NULL)) {
875 bstats_update(&cl->bstats, skb);
876 cl->leaf.deficit[level] -= qdisc_pkt_len(skb);
877 if (cl->leaf.deficit[level] < 0) {
878 cl->leaf.deficit[level] += cl->quantum;
879 htb_next_rb_node(level ? &cl->parent->inner.clprio[prio].ptr :
880 &q->hlevel[0].hprio[prio].ptr);
882 /* this used to be after charge_class but this constelation
883 * gives us slightly better performance
885 if (!cl->leaf.q->q.qlen)
886 htb_deactivate(q, cl);
887 htb_charge_class(q, cl, level, skb);
892 static struct sk_buff *htb_dequeue(struct Qdisc *sch)
895 struct htb_sched *q = qdisc_priv(sch);
898 unsigned long start_at;
900 /* try to dequeue direct packets as high prio (!) to minimize cpu work */
901 skb = __qdisc_dequeue_head(&q->direct_queue);
904 qdisc_bstats_update(sch, skb);
905 qdisc_qstats_backlog_dec(sch, skb);
912 q->now = ktime_get_ns();
915 next_event = q->now + 5LLU * NSEC_PER_SEC;
917 for (level = 0; level < TC_HTB_MAXDEPTH; level++) {
918 /* common case optimization - skip event handler quickly */
920 s64 event = q->near_ev_cache[level];
922 if (q->now >= event) {
923 event = htb_do_events(q, level, start_at);
925 event = q->now + NSEC_PER_SEC;
926 q->near_ev_cache[level] = event;
929 if (next_event > event)
932 m = ~q->row_mask[level];
933 while (m != (int)(-1)) {
937 skb = htb_dequeue_tree(q, prio, level);
938 if (likely(skb != NULL))
942 if (likely(next_event > q->now))
943 qdisc_watchdog_schedule_ns(&q->watchdog, next_event);
945 schedule_work(&q->work);
950 /* reset all classes */
951 /* always caled under BH & queue lock */
952 static void htb_reset(struct Qdisc *sch)
954 struct htb_sched *q = qdisc_priv(sch);
955 struct htb_class *cl;
958 for (i = 0; i < q->clhash.hashsize; i++) {
959 hlist_for_each_entry(cl, &q->clhash.hash[i], common.hnode) {
961 memset(&cl->inner, 0, sizeof(cl->inner));
964 qdisc_reset(cl->leaf.q);
966 cl->prio_activity = 0;
967 cl->cmode = HTB_CAN_SEND;
970 qdisc_watchdog_cancel(&q->watchdog);
971 __qdisc_reset_queue(&q->direct_queue);
972 memset(q->hlevel, 0, sizeof(q->hlevel));
973 memset(q->row_mask, 0, sizeof(q->row_mask));
976 static const struct nla_policy htb_policy[TCA_HTB_MAX + 1] = {
977 [TCA_HTB_PARMS] = { .len = sizeof(struct tc_htb_opt) },
978 [TCA_HTB_INIT] = { .len = sizeof(struct tc_htb_glob) },
979 [TCA_HTB_CTAB] = { .type = NLA_BINARY, .len = TC_RTAB_SIZE },
980 [TCA_HTB_RTAB] = { .type = NLA_BINARY, .len = TC_RTAB_SIZE },
981 [TCA_HTB_DIRECT_QLEN] = { .type = NLA_U32 },
982 [TCA_HTB_RATE64] = { .type = NLA_U64 },
983 [TCA_HTB_CEIL64] = { .type = NLA_U64 },
986 static void htb_work_func(struct work_struct *work)
988 struct htb_sched *q = container_of(work, struct htb_sched, work);
989 struct Qdisc *sch = q->watchdog.qdisc;
992 __netif_schedule(qdisc_root(sch));
996 static int htb_init(struct Qdisc *sch, struct nlattr *opt,
997 struct netlink_ext_ack *extack)
999 struct htb_sched *q = qdisc_priv(sch);
1000 struct nlattr *tb[TCA_HTB_MAX + 1];
1001 struct tc_htb_glob *gopt;
1004 qdisc_watchdog_init(&q->watchdog, sch);
1005 INIT_WORK(&q->work, htb_work_func);
1010 err = tcf_block_get(&q->block, &q->filter_list, sch, extack);
1014 err = nla_parse_nested_deprecated(tb, TCA_HTB_MAX, opt, htb_policy,
1019 if (!tb[TCA_HTB_INIT])
1022 gopt = nla_data(tb[TCA_HTB_INIT]);
1023 if (gopt->version != HTB_VER >> 16)
1026 err = qdisc_class_hash_init(&q->clhash);
1030 qdisc_skb_head_init(&q->direct_queue);
1032 if (tb[TCA_HTB_DIRECT_QLEN])
1033 q->direct_qlen = nla_get_u32(tb[TCA_HTB_DIRECT_QLEN]);
1035 q->direct_qlen = qdisc_dev(sch)->tx_queue_len;
1037 if ((q->rate2quantum = gopt->rate2quantum) < 1)
1038 q->rate2quantum = 1;
1039 q->defcls = gopt->defcls;
1044 static int htb_dump(struct Qdisc *sch, struct sk_buff *skb)
1046 struct htb_sched *q = qdisc_priv(sch);
1047 struct nlattr *nest;
1048 struct tc_htb_glob gopt;
1050 sch->qstats.overlimits = q->overlimits;
1051 /* Its safe to not acquire qdisc lock. As we hold RTNL,
1052 * no change can happen on the qdisc parameters.
1055 gopt.direct_pkts = q->direct_pkts;
1056 gopt.version = HTB_VER;
1057 gopt.rate2quantum = q->rate2quantum;
1058 gopt.defcls = q->defcls;
1061 nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
1063 goto nla_put_failure;
1064 if (nla_put(skb, TCA_HTB_INIT, sizeof(gopt), &gopt) ||
1065 nla_put_u32(skb, TCA_HTB_DIRECT_QLEN, q->direct_qlen))
1066 goto nla_put_failure;
1068 return nla_nest_end(skb, nest);
1071 nla_nest_cancel(skb, nest);
1075 static int htb_dump_class(struct Qdisc *sch, unsigned long arg,
1076 struct sk_buff *skb, struct tcmsg *tcm)
1078 struct htb_class *cl = (struct htb_class *)arg;
1079 struct nlattr *nest;
1080 struct tc_htb_opt opt;
1082 /* Its safe to not acquire qdisc lock. As we hold RTNL,
1083 * no change can happen on the class parameters.
1085 tcm->tcm_parent = cl->parent ? cl->parent->common.classid : TC_H_ROOT;
1086 tcm->tcm_handle = cl->common.classid;
1087 if (!cl->level && cl->leaf.q)
1088 tcm->tcm_info = cl->leaf.q->handle;
1090 nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
1092 goto nla_put_failure;
1094 memset(&opt, 0, sizeof(opt));
1096 psched_ratecfg_getrate(&opt.rate, &cl->rate);
1097 opt.buffer = PSCHED_NS2TICKS(cl->buffer);
1098 psched_ratecfg_getrate(&opt.ceil, &cl->ceil);
1099 opt.cbuffer = PSCHED_NS2TICKS(cl->cbuffer);
1100 opt.quantum = cl->quantum;
1101 opt.prio = cl->prio;
1102 opt.level = cl->level;
1103 if (nla_put(skb, TCA_HTB_PARMS, sizeof(opt), &opt))
1104 goto nla_put_failure;
1105 if ((cl->rate.rate_bytes_ps >= (1ULL << 32)) &&
1106 nla_put_u64_64bit(skb, TCA_HTB_RATE64, cl->rate.rate_bytes_ps,
1108 goto nla_put_failure;
1109 if ((cl->ceil.rate_bytes_ps >= (1ULL << 32)) &&
1110 nla_put_u64_64bit(skb, TCA_HTB_CEIL64, cl->ceil.rate_bytes_ps,
1112 goto nla_put_failure;
1114 return nla_nest_end(skb, nest);
1117 nla_nest_cancel(skb, nest);
1122 htb_dump_class_stats(struct Qdisc *sch, unsigned long arg, struct gnet_dump *d)
1124 struct htb_class *cl = (struct htb_class *)arg;
1125 struct gnet_stats_queue qs = {
1127 .overlimits = cl->overlimits,
1131 if (!cl->level && cl->leaf.q)
1132 qdisc_qstats_qlen_backlog(cl->leaf.q, &qlen, &qs.backlog);
1134 cl->xstats.tokens = clamp_t(s64, PSCHED_NS2TICKS(cl->tokens),
1136 cl->xstats.ctokens = clamp_t(s64, PSCHED_NS2TICKS(cl->ctokens),
1139 if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
1140 d, NULL, &cl->bstats) < 0 ||
1141 gnet_stats_copy_rate_est(d, &cl->rate_est) < 0 ||
1142 gnet_stats_copy_queue(d, NULL, &qs, qlen) < 0)
1145 return gnet_stats_copy_app(d, &cl->xstats, sizeof(cl->xstats));
1148 static int htb_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
1149 struct Qdisc **old, struct netlink_ext_ack *extack)
1151 struct htb_class *cl = (struct htb_class *)arg;
1156 (new = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
1157 cl->common.classid, extack)) == NULL)
1160 *old = qdisc_replace(sch, new, &cl->leaf.q);
1164 static struct Qdisc *htb_leaf(struct Qdisc *sch, unsigned long arg)
1166 struct htb_class *cl = (struct htb_class *)arg;
1167 return !cl->level ? cl->leaf.q : NULL;
1170 static void htb_qlen_notify(struct Qdisc *sch, unsigned long arg)
1172 struct htb_class *cl = (struct htb_class *)arg;
1174 htb_deactivate(qdisc_priv(sch), cl);
1177 static inline int htb_parent_last_child(struct htb_class *cl)
1180 /* the root class */
1182 if (cl->parent->children > 1)
1183 /* not the last child */
1188 static void htb_parent_to_leaf(struct htb_sched *q, struct htb_class *cl,
1189 struct Qdisc *new_q)
1191 struct htb_class *parent = cl->parent;
1193 WARN_ON(cl->level || !cl->leaf.q || cl->prio_activity);
1195 if (parent->cmode != HTB_CAN_SEND)
1196 htb_safe_rb_erase(&parent->pq_node,
1197 &q->hlevel[parent->level].wait_pq);
1200 memset(&parent->inner, 0, sizeof(parent->inner));
1201 parent->leaf.q = new_q ? new_q : &noop_qdisc;
1202 parent->tokens = parent->buffer;
1203 parent->ctokens = parent->cbuffer;
1204 parent->t_c = ktime_get_ns();
1205 parent->cmode = HTB_CAN_SEND;
1208 static void htb_destroy_class(struct Qdisc *sch, struct htb_class *cl)
1211 WARN_ON(!cl->leaf.q);
1212 qdisc_put(cl->leaf.q);
1214 gen_kill_estimator(&cl->rate_est);
1215 tcf_block_put(cl->block);
1219 static void htb_destroy(struct Qdisc *sch)
1221 struct htb_sched *q = qdisc_priv(sch);
1222 struct hlist_node *next;
1223 struct htb_class *cl;
1226 cancel_work_sync(&q->work);
1227 qdisc_watchdog_cancel(&q->watchdog);
1228 /* This line used to be after htb_destroy_class call below
1229 * and surprisingly it worked in 2.4. But it must precede it
1230 * because filter need its target class alive to be able to call
1231 * unbind_filter on it (without Oops).
1233 tcf_block_put(q->block);
1235 for (i = 0; i < q->clhash.hashsize; i++) {
1236 hlist_for_each_entry(cl, &q->clhash.hash[i], common.hnode) {
1237 tcf_block_put(cl->block);
1241 for (i = 0; i < q->clhash.hashsize; i++) {
1242 hlist_for_each_entry_safe(cl, next, &q->clhash.hash[i],
1244 htb_destroy_class(sch, cl);
1246 qdisc_class_hash_destroy(&q->clhash);
1247 __qdisc_reset_queue(&q->direct_queue);
1250 static int htb_delete(struct Qdisc *sch, unsigned long arg)
1252 struct htb_sched *q = qdisc_priv(sch);
1253 struct htb_class *cl = (struct htb_class *)arg;
1254 struct Qdisc *new_q = NULL;
1257 /* TODO: why don't allow to delete subtree ? references ? does
1258 * tc subsys guarantee us that in htb_destroy it holds no class
1259 * refs so that we can remove children safely there ?
1261 if (cl->children || cl->filter_cnt)
1264 if (!cl->level && htb_parent_last_child(cl)) {
1265 new_q = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
1266 cl->parent->common.classid,
1274 qdisc_purge_queue(cl->leaf.q);
1276 /* delete from hash and active; remainder in destroy_class */
1277 qdisc_class_hash_remove(&q->clhash, &cl->common);
1279 cl->parent->children--;
1281 if (cl->prio_activity)
1282 htb_deactivate(q, cl);
1284 if (cl->cmode != HTB_CAN_SEND)
1285 htb_safe_rb_erase(&cl->pq_node,
1286 &q->hlevel[cl->level].wait_pq);
1289 htb_parent_to_leaf(q, cl, new_q);
1291 sch_tree_unlock(sch);
1293 htb_destroy_class(sch, cl);
1297 static int htb_change_class(struct Qdisc *sch, u32 classid,
1298 u32 parentid, struct nlattr **tca,
1299 unsigned long *arg, struct netlink_ext_ack *extack)
1302 struct htb_sched *q = qdisc_priv(sch);
1303 struct htb_class *cl = (struct htb_class *)*arg, *parent;
1304 struct nlattr *opt = tca[TCA_OPTIONS];
1305 struct nlattr *tb[TCA_HTB_MAX + 1];
1306 struct Qdisc *parent_qdisc = NULL;
1307 struct tc_htb_opt *hopt;
1311 /* extract all subattrs from opt attr */
1315 err = nla_parse_nested_deprecated(tb, TCA_HTB_MAX, opt, htb_policy,
1321 if (tb[TCA_HTB_PARMS] == NULL)
1324 parent = parentid == TC_H_ROOT ? NULL : htb_find(parentid, sch);
1326 hopt = nla_data(tb[TCA_HTB_PARMS]);
1327 if (!hopt->rate.rate || !hopt->ceil.rate)
1330 /* Keeping backward compatible with rate_table based iproute2 tc */
1331 if (hopt->rate.linklayer == TC_LINKLAYER_UNAWARE)
1332 qdisc_put_rtab(qdisc_get_rtab(&hopt->rate, tb[TCA_HTB_RTAB],
1335 if (hopt->ceil.linklayer == TC_LINKLAYER_UNAWARE)
1336 qdisc_put_rtab(qdisc_get_rtab(&hopt->ceil, tb[TCA_HTB_CTAB],
1339 if (!cl) { /* new class */
1340 struct Qdisc *new_q;
1344 struct gnet_estimator opt;
1347 .nla_len = nla_attr_size(sizeof(est.opt)),
1348 .nla_type = TCA_RATE,
1351 /* 4s interval, 16s averaging constant */
1357 /* check for valid classid */
1358 if (!classid || TC_H_MAJ(classid ^ sch->handle) ||
1359 htb_find(classid, sch))
1362 /* check maximal depth */
1363 if (parent && parent->parent && parent->parent->level < 2) {
1364 pr_err("htb: tree is too deep\n");
1368 cl = kzalloc(sizeof(*cl), GFP_KERNEL);
1372 err = tcf_block_get(&cl->block, &cl->filter_list, sch, extack);
1377 if (htb_rate_est || tca[TCA_RATE]) {
1378 err = gen_new_estimator(&cl->bstats, NULL,
1381 qdisc_root_sleeping_running(sch),
1382 tca[TCA_RATE] ? : &est.nla);
1384 tcf_block_put(cl->block);
1391 RB_CLEAR_NODE(&cl->pq_node);
1393 for (prio = 0; prio < TC_HTB_NUMPRIO; prio++)
1394 RB_CLEAR_NODE(&cl->node[prio]);
1396 /* create leaf qdisc early because it uses kmalloc(GFP_KERNEL)
1397 * so that can't be used inside of sch_tree_lock
1398 * -- thanks to Karlis Peisenieks
1400 new_q = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
1403 if (parent && !parent->level) {
1404 /* turn parent into inner node */
1405 qdisc_purge_queue(parent->leaf.q);
1406 parent_qdisc = parent->leaf.q;
1407 if (parent->prio_activity)
1408 htb_deactivate(q, parent);
1410 /* remove from evt list because of level change */
1411 if (parent->cmode != HTB_CAN_SEND) {
1412 htb_safe_rb_erase(&parent->pq_node, &q->hlevel[0].wait_pq);
1413 parent->cmode = HTB_CAN_SEND;
1415 parent->level = (parent->parent ? parent->parent->level
1416 : TC_HTB_MAXDEPTH) - 1;
1417 memset(&parent->inner, 0, sizeof(parent->inner));
1419 /* leaf (we) needs elementary qdisc */
1420 cl->leaf.q = new_q ? new_q : &noop_qdisc;
1422 cl->common.classid = classid;
1423 cl->parent = parent;
1425 /* set class to be in HTB_CAN_SEND state */
1426 cl->tokens = PSCHED_TICKS2NS(hopt->buffer);
1427 cl->ctokens = PSCHED_TICKS2NS(hopt->cbuffer);
1428 cl->mbuffer = 60ULL * NSEC_PER_SEC; /* 1min */
1429 cl->t_c = ktime_get_ns();
1430 cl->cmode = HTB_CAN_SEND;
1432 /* attach to the hash list and parent's family */
1433 qdisc_class_hash_insert(&q->clhash, &cl->common);
1436 if (cl->leaf.q != &noop_qdisc)
1437 qdisc_hash_add(cl->leaf.q, true);
1439 if (tca[TCA_RATE]) {
1440 err = gen_replace_estimator(&cl->bstats, NULL,
1443 qdisc_root_sleeping_running(sch),
1451 rate64 = tb[TCA_HTB_RATE64] ? nla_get_u64(tb[TCA_HTB_RATE64]) : 0;
1453 ceil64 = tb[TCA_HTB_CEIL64] ? nla_get_u64(tb[TCA_HTB_CEIL64]) : 0;
1455 psched_ratecfg_precompute(&cl->rate, &hopt->rate, rate64);
1456 psched_ratecfg_precompute(&cl->ceil, &hopt->ceil, ceil64);
1458 /* it used to be a nasty bug here, we have to check that node
1459 * is really leaf before changing cl->leaf !
1462 u64 quantum = cl->rate.rate_bytes_ps;
1464 do_div(quantum, q->rate2quantum);
1465 cl->quantum = min_t(u64, quantum, INT_MAX);
1467 if (!hopt->quantum && cl->quantum < 1000) {
1471 if (!hopt->quantum && cl->quantum > 200000) {
1473 cl->quantum = 200000;
1476 cl->quantum = hopt->quantum;
1477 if ((cl->prio = hopt->prio) >= TC_HTB_NUMPRIO)
1478 cl->prio = TC_HTB_NUMPRIO - 1;
1481 cl->buffer = PSCHED_TICKS2NS(hopt->buffer);
1482 cl->cbuffer = PSCHED_TICKS2NS(hopt->cbuffer);
1484 sch_tree_unlock(sch);
1485 qdisc_put(parent_qdisc);
1488 pr_warn("HTB: quantum of class %X is %s. Consider r2q change.\n",
1489 cl->common.classid, (warn == -1 ? "small" : "big"));
1491 qdisc_class_hash_grow(sch, &q->clhash);
1493 *arg = (unsigned long)cl;
1500 static struct tcf_block *htb_tcf_block(struct Qdisc *sch, unsigned long arg,
1501 struct netlink_ext_ack *extack)
1503 struct htb_sched *q = qdisc_priv(sch);
1504 struct htb_class *cl = (struct htb_class *)arg;
1506 return cl ? cl->block : q->block;
1509 static unsigned long htb_bind_filter(struct Qdisc *sch, unsigned long parent,
1512 struct htb_class *cl = htb_find(classid, sch);
1514 /*if (cl && !cl->level) return 0;
1515 * The line above used to be there to prevent attaching filters to
1516 * leaves. But at least tc_index filter uses this just to get class
1517 * for other reasons so that we have to allow for it.
1519 * 19.6.2002 As Werner explained it is ok - bind filter is just
1520 * another way to "lock" the class - unlike "get" this lock can
1521 * be broken by class during destroy IIUC.
1525 return (unsigned long)cl;
1528 static void htb_unbind_filter(struct Qdisc *sch, unsigned long arg)
1530 struct htb_class *cl = (struct htb_class *)arg;
1536 static void htb_walk(struct Qdisc *sch, struct qdisc_walker *arg)
1538 struct htb_sched *q = qdisc_priv(sch);
1539 struct htb_class *cl;
1545 for (i = 0; i < q->clhash.hashsize; i++) {
1546 hlist_for_each_entry(cl, &q->clhash.hash[i], common.hnode) {
1547 if (arg->count < arg->skip) {
1551 if (arg->fn(sch, (unsigned long)cl, arg) < 0) {
1560 static const struct Qdisc_class_ops htb_class_ops = {
1563 .qlen_notify = htb_qlen_notify,
1565 .change = htb_change_class,
1566 .delete = htb_delete,
1568 .tcf_block = htb_tcf_block,
1569 .bind_tcf = htb_bind_filter,
1570 .unbind_tcf = htb_unbind_filter,
1571 .dump = htb_dump_class,
1572 .dump_stats = htb_dump_class_stats,
1575 static struct Qdisc_ops htb_qdisc_ops __read_mostly = {
1576 .cl_ops = &htb_class_ops,
1578 .priv_size = sizeof(struct htb_sched),
1579 .enqueue = htb_enqueue,
1580 .dequeue = htb_dequeue,
1581 .peek = qdisc_peek_dequeued,
1584 .destroy = htb_destroy,
1586 .owner = THIS_MODULE,
1589 static int __init htb_module_init(void)
1591 return register_qdisc(&htb_qdisc_ops);
1593 static void __exit htb_module_exit(void)
1595 unregister_qdisc(&htb_qdisc_ops);
1598 module_init(htb_module_init)
1599 module_exit(htb_module_exit)
1600 MODULE_LICENSE("GPL");