2 * net/sched/sch_htb.c Hierarchical token bucket, feed tree version
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.
9 * Authors: Martin Devera, <devik@cdi.cz>
11 * Credits (in time order) for older HTB versions:
12 * Stef Coene <stef.coene@docum.org>
13 * HTB support at LARTC mailing list
14 * Ondrej Kraus, <krauso@barr.cz>
15 * found missing INIT_QDISC(htb)
16 * Vladimir Smelhaus, Aamer Akhter, Bert Hubert
17 * helped a lot to locate nasty class stall bug
18 * Andi Kleen, Jamal Hadi, Bert Hubert
19 * code review and helpful comments on shaping
20 * Tomasz Wrona, <tw@eter.tym.pl>
21 * created test case so that I was able to fix nasty bug
23 * spotted bug in dequeue code and helped with fix
25 * fixed requeue routine
26 * and many others. thanks.
28 * $Id: sch_htb.c,v 1.25 2003/12/07 11:08:25 devik Exp devik $
30 #include <linux/module.h>
31 #include <asm/uaccess.h>
32 #include <asm/system.h>
33 #include <linux/bitops.h>
34 #include <linux/types.h>
35 #include <linux/kernel.h>
36 #include <linux/string.h>
38 #include <linux/socket.h>
39 #include <linux/sockios.h>
41 #include <linux/errno.h>
42 #include <linux/interrupt.h>
43 #include <linux/if_ether.h>
44 #include <linux/inet.h>
45 #include <linux/netdevice.h>
46 #include <linux/etherdevice.h>
47 #include <linux/notifier.h>
49 #include <net/route.h>
50 #include <linux/skbuff.h>
51 #include <linux/list.h>
52 #include <linux/compiler.h>
53 #include <net/netlink.h>
55 #include <net/pkt_sched.h>
56 #include <linux/rbtree.h>
60 ========================================================================
61 HTB is like TBF with multiple classes. It is also similar to CBQ because
62 it allows to assign priority to each class in hierarchy.
63 In fact it is another implementation of Floyd's formal sharing.
66 Each class is assigned level. Leaf has ALWAYS level 0 and root
67 classes have level TC_HTB_MAXDEPTH-1. Interior nodes has level
68 one less than their parent.
71 #define HTB_HSIZE 16 /* classid hash size */
72 #define HTB_HYSTERESIS 1 /* whether to use mode hysteresis for speedup */
73 #define HTB_VER 0x30011 /* major must be matched with number suplied by TC as version */
75 #if HTB_VER >> 16 != TC_HTB_PROTOVER
76 #error "Mismatched sch_htb.c and pkt_sch.h"
79 /* used internaly to keep status of single class */
81 HTB_CANT_SEND, /* class can't send and can't borrow */
82 HTB_MAY_BORROW, /* class can't send but may borrow */
83 HTB_CAN_SEND /* class can send */
86 /* interior & leaf nodes; props specific to leaves are marked L: */
88 /* general class parameters */
90 struct gnet_stats_basic bstats;
91 struct gnet_stats_queue qstats;
92 struct gnet_stats_rate_est rate_est;
93 struct tc_htb_xstats xstats; /* our special stats */
94 int refcnt; /* usage count of this class */
97 int level; /* our level (see above) */
98 struct htb_class *parent; /* parent class */
99 struct hlist_node hlist; /* classid hash list item */
100 struct list_head sibling; /* sibling list item */
101 struct list_head children; /* children list */
104 struct htb_class_leaf {
109 int deficit[TC_HTB_MAXDEPTH];
110 struct list_head drop_list;
112 struct htb_class_inner {
113 struct rb_root feed[TC_HTB_NUMPRIO]; /* feed trees */
114 struct rb_node *ptr[TC_HTB_NUMPRIO]; /* current class ptr */
115 /* When class changes from state 1->2 and disconnects from
116 parent's feed then we lost ptr value and start from the
117 first child again. Here we store classid of the
118 last valid ptr (used when ptr is NULL). */
119 u32 last_ptr_id[TC_HTB_NUMPRIO];
122 struct rb_node node[TC_HTB_NUMPRIO]; /* node for self or feed tree */
123 struct rb_node pq_node; /* node for event queue */
124 psched_time_t pq_key;
126 int prio_activity; /* for which prios are we active */
127 enum htb_cmode cmode; /* current mode of the class */
129 /* class attached filters */
130 struct tcf_proto *filter_list;
133 int warned; /* only one warning about non work conserving .. */
135 /* token bucket parameters */
136 struct qdisc_rate_table *rate; /* rate table of the class itself */
137 struct qdisc_rate_table *ceil; /* ceiling rate (limits borrows too) */
138 long buffer, cbuffer; /* token bucket depth/rate */
139 psched_tdiff_t mbuffer; /* max wait time */
140 long tokens, ctokens; /* current number of tokens */
141 psched_time_t t_c; /* checkpoint time */
143 int prio; /* For parent to leaf return possible here */
144 int quantum; /* we do backup. Finally full replacement */
145 /* of un.leaf originals should be done. */
148 /* TODO: maybe compute rate when size is too large .. or drop ? */
149 static inline long L2T(struct htb_class *cl, struct qdisc_rate_table *rate,
152 int slot = size >> rate->rate.cell_log;
157 return rate->data[slot];
161 struct list_head root; /* root classes list */
162 struct hlist_head hash[HTB_HSIZE]; /* hashed by classid */
163 struct list_head drops[TC_HTB_NUMPRIO];/* active leaves (for drops) */
165 /* self list - roots of self generating tree */
166 struct rb_root row[TC_HTB_MAXDEPTH][TC_HTB_NUMPRIO];
167 int row_mask[TC_HTB_MAXDEPTH];
168 struct rb_node *ptr[TC_HTB_MAXDEPTH][TC_HTB_NUMPRIO];
169 u32 last_ptr_id[TC_HTB_MAXDEPTH][TC_HTB_NUMPRIO];
171 /* self wait list - roots of wait PQs per row */
172 struct rb_root wait_pq[TC_HTB_MAXDEPTH];
174 /* time of nearest event per level (row) */
175 psched_time_t near_ev_cache[TC_HTB_MAXDEPTH];
177 /* whether we hit non-work conserving class during this dequeue; we use */
178 int nwc_hit; /* this to disable mindelay complaint in dequeue */
180 int defcls; /* class where unclassified flows go to */
182 /* filters for qdisc itself */
183 struct tcf_proto *filter_list;
186 int rate2quantum; /* quant = rate / rate2quantum */
187 psched_time_t now; /* cached dequeue time */
188 struct qdisc_watchdog watchdog;
190 /* non shaped skbs; let them go directly thru */
191 struct sk_buff_head direct_queue;
192 int direct_qlen; /* max qlen of above */
197 /* compute hash of size HTB_HSIZE for given handle */
198 static inline int htb_hash(u32 h)
201 #error "Declare new hash for your HTB_HSIZE"
203 h ^= h >> 8; /* stolen from cbq_hash */
208 /* find class in global hash table using given handle */
209 static inline struct htb_class *htb_find(u32 handle, struct Qdisc *sch)
211 struct htb_sched *q = qdisc_priv(sch);
212 struct hlist_node *p;
213 struct htb_class *cl;
215 if (TC_H_MAJ(handle) != sch->handle)
218 hlist_for_each_entry(cl, p, q->hash + htb_hash(handle), hlist) {
219 if (cl->classid == handle)
226 * htb_classify - classify a packet into class
228 * It returns NULL if the packet should be dropped or -1 if the packet
229 * should be passed directly thru. In all other cases leaf class is returned.
230 * We allow direct class selection by classid in priority. The we examine
231 * filters in qdisc and in inner nodes (if higher filter points to the inner
232 * node). If we end up with classid MAJOR:0 we enqueue the skb into special
233 * internal fifo (direct). These packets then go directly thru. If we still
234 * have no valid leaf we try to use MAJOR:default leaf. It still unsuccessfull
235 * then finish and return direct queue.
237 #define HTB_DIRECT (struct htb_class*)-1
238 static inline u32 htb_classid(struct htb_class *cl)
240 return (cl && cl != HTB_DIRECT) ? cl->classid : TC_H_UNSPEC;
243 static struct htb_class *htb_classify(struct sk_buff *skb, struct Qdisc *sch,
246 struct htb_sched *q = qdisc_priv(sch);
247 struct htb_class *cl;
248 struct tcf_result res;
249 struct tcf_proto *tcf;
252 /* allow to select class by setting skb->priority to valid classid;
253 note that nfmark can be used too by attaching filter fw with no
255 if (skb->priority == sch->handle)
256 return HTB_DIRECT; /* X:0 (direct flow) selected */
257 if ((cl = htb_find(skb->priority, sch)) != NULL && cl->level == 0)
260 *qerr = NET_XMIT_BYPASS;
261 tcf = q->filter_list;
262 while (tcf && (result = tc_classify(skb, tcf, &res)) >= 0) {
263 #ifdef CONFIG_NET_CLS_ACT
267 *qerr = NET_XMIT_SUCCESS;
271 #elif defined(CONFIG_NET_CLS_POLICE)
272 if (result == TC_POLICE_SHOT)
275 if ((cl = (void *)res.class) == NULL) {
276 if (res.classid == sch->handle)
277 return HTB_DIRECT; /* X:0 (direct flow) */
278 if ((cl = htb_find(res.classid, sch)) == NULL)
279 break; /* filter selected invalid classid */
282 return cl; /* we hit leaf; return it */
284 /* we have got inner class; apply inner filter chain */
285 tcf = cl->filter_list;
287 /* classification failed; try to use default class */
288 cl = htb_find(TC_H_MAKE(TC_H_MAJ(sch->handle), q->defcls), sch);
289 if (!cl || cl->level)
290 return HTB_DIRECT; /* bad default .. this is safe bet */
295 * htb_add_to_id_tree - adds class to the round robin list
297 * Routine adds class to the list (actually tree) sorted by classid.
298 * Make sure that class is not already on such list for given prio.
300 static void htb_add_to_id_tree(struct rb_root *root,
301 struct htb_class *cl, int prio)
303 struct rb_node **p = &root->rb_node, *parent = NULL;
308 c = rb_entry(parent, struct htb_class, node[prio]);
310 if (cl->classid > c->classid)
311 p = &parent->rb_right;
313 p = &parent->rb_left;
315 rb_link_node(&cl->node[prio], parent, p);
316 rb_insert_color(&cl->node[prio], root);
320 * htb_add_to_wait_tree - adds class to the event queue with delay
322 * The class is added to priority event queue to indicate that class will
323 * change its mode in cl->pq_key microseconds. Make sure that class is not
324 * already in the queue.
326 static void htb_add_to_wait_tree(struct htb_sched *q,
327 struct htb_class *cl, long delay)
329 struct rb_node **p = &q->wait_pq[cl->level].rb_node, *parent = NULL;
331 cl->pq_key = q->now + delay;
332 if (cl->pq_key == q->now)
335 /* update the nearest event cache */
336 if (q->near_ev_cache[cl->level] > cl->pq_key)
337 q->near_ev_cache[cl->level] = cl->pq_key;
342 c = rb_entry(parent, struct htb_class, pq_node);
343 if (cl->pq_key >= c->pq_key)
344 p = &parent->rb_right;
346 p = &parent->rb_left;
348 rb_link_node(&cl->pq_node, parent, p);
349 rb_insert_color(&cl->pq_node, &q->wait_pq[cl->level]);
353 * htb_next_rb_node - finds next node in binary tree
355 * When we are past last key we return NULL.
356 * Average complexity is 2 steps per call.
358 static inline void htb_next_rb_node(struct rb_node **n)
364 * htb_add_class_to_row - add class to its row
366 * The class is added to row at priorities marked in mask.
367 * It does nothing if mask == 0.
369 static inline void htb_add_class_to_row(struct htb_sched *q,
370 struct htb_class *cl, int mask)
372 q->row_mask[cl->level] |= mask;
374 int prio = ffz(~mask);
375 mask &= ~(1 << prio);
376 htb_add_to_id_tree(q->row[cl->level] + prio, cl, prio);
380 /* If this triggers, it is a bug in this code, but it need not be fatal */
381 static void htb_safe_rb_erase(struct rb_node *rb, struct rb_root *root)
383 if (RB_EMPTY_NODE(rb)) {
393 * htb_remove_class_from_row - removes class from its row
395 * The class is removed from row at priorities marked in mask.
396 * It does nothing if mask == 0.
398 static inline void htb_remove_class_from_row(struct htb_sched *q,
399 struct htb_class *cl, int mask)
404 int prio = ffz(~mask);
406 mask &= ~(1 << prio);
407 if (q->ptr[cl->level][prio] == cl->node + prio)
408 htb_next_rb_node(q->ptr[cl->level] + prio);
410 htb_safe_rb_erase(cl->node + prio, q->row[cl->level] + prio);
411 if (!q->row[cl->level][prio].rb_node)
414 q->row_mask[cl->level] &= ~m;
418 * htb_activate_prios - creates active classe's feed chain
420 * The class is connected to ancestors and/or appropriate rows
421 * for priorities it is participating on. cl->cmode must be new
422 * (activated) mode. It does nothing if cl->prio_activity == 0.
424 static void htb_activate_prios(struct htb_sched *q, struct htb_class *cl)
426 struct htb_class *p = cl->parent;
427 long m, mask = cl->prio_activity;
429 while (cl->cmode == HTB_MAY_BORROW && p && mask) {
435 if (p->un.inner.feed[prio].rb_node)
436 /* parent already has its feed in use so that
437 reset bit in mask as parent is already ok */
438 mask &= ~(1 << prio);
440 htb_add_to_id_tree(p->un.inner.feed + prio, cl, prio);
442 p->prio_activity |= mask;
447 if (cl->cmode == HTB_CAN_SEND && mask)
448 htb_add_class_to_row(q, cl, mask);
452 * htb_deactivate_prios - remove class from feed chain
454 * cl->cmode must represent old mode (before deactivation). It does
455 * nothing if cl->prio_activity == 0. Class is removed from all feed
458 static void htb_deactivate_prios(struct htb_sched *q, struct htb_class *cl)
460 struct htb_class *p = cl->parent;
461 long m, mask = cl->prio_activity;
463 while (cl->cmode == HTB_MAY_BORROW && p && mask) {
470 if (p->un.inner.ptr[prio] == cl->node + prio) {
471 /* we are removing child which is pointed to from
472 parent feed - forget the pointer but remember
474 p->un.inner.last_ptr_id[prio] = cl->classid;
475 p->un.inner.ptr[prio] = NULL;
478 htb_safe_rb_erase(cl->node + prio, p->un.inner.feed + prio);
480 if (!p->un.inner.feed[prio].rb_node)
484 p->prio_activity &= ~mask;
489 if (cl->cmode == HTB_CAN_SEND && mask)
490 htb_remove_class_from_row(q, cl, mask);
494 static inline long htb_lowater(const struct htb_class *cl)
496 return cl->cmode != HTB_CANT_SEND ? -cl->cbuffer : 0;
498 static inline long htb_hiwater(const struct htb_class *cl)
500 return cl->cmode == HTB_CAN_SEND ? -cl->buffer : 0;
503 #define htb_lowater(cl) (0)
504 #define htb_hiwater(cl) (0)
508 * htb_class_mode - computes and returns current class mode
510 * It computes cl's mode at time cl->t_c+diff and returns it. If mode
511 * is not HTB_CAN_SEND then cl->pq_key is updated to time difference
512 * from now to time when cl will change its state.
513 * Also it is worth to note that class mode doesn't change simply
514 * at cl->{c,}tokens == 0 but there can rather be hysteresis of
515 * 0 .. -cl->{c,}buffer range. It is meant to limit number of
516 * mode transitions per time unit. The speed gain is about 1/6.
518 static inline enum htb_cmode
519 htb_class_mode(struct htb_class *cl, long *diff)
523 if ((toks = (cl->ctokens + *diff)) < htb_lowater(cl)) {
525 return HTB_CANT_SEND;
528 if ((toks = (cl->tokens + *diff)) >= htb_hiwater(cl))
532 return HTB_MAY_BORROW;
536 * htb_change_class_mode - changes classe's mode
538 * This should be the only way how to change classe's mode under normal
539 * cirsumstances. Routine will update feed lists linkage, change mode
540 * and add class to the wait event queue if appropriate. New mode should
541 * be different from old one and cl->pq_key has to be valid if changing
542 * to mode other than HTB_CAN_SEND (see htb_add_to_wait_tree).
545 htb_change_class_mode(struct htb_sched *q, struct htb_class *cl, long *diff)
547 enum htb_cmode new_mode = htb_class_mode(cl, diff);
549 if (new_mode == cl->cmode)
552 if (cl->prio_activity) { /* not necessary: speed optimization */
553 if (cl->cmode != HTB_CANT_SEND)
554 htb_deactivate_prios(q, cl);
555 cl->cmode = new_mode;
556 if (new_mode != HTB_CANT_SEND)
557 htb_activate_prios(q, cl);
559 cl->cmode = new_mode;
563 * htb_activate - inserts leaf cl into appropriate active feeds
565 * Routine learns (new) priority of leaf and activates feed chain
566 * for the prio. It can be called on already active leaf safely.
567 * It also adds leaf into droplist.
569 static inline void htb_activate(struct htb_sched *q, struct htb_class *cl)
571 BUG_TRAP(!cl->level && cl->un.leaf.q && cl->un.leaf.q->q.qlen);
573 if (!cl->prio_activity) {
574 cl->prio_activity = 1 << (cl->un.leaf.aprio = cl->un.leaf.prio);
575 htb_activate_prios(q, cl);
576 list_add_tail(&cl->un.leaf.drop_list,
577 q->drops + cl->un.leaf.aprio);
582 * htb_deactivate - remove leaf cl from active feeds
584 * Make sure that leaf is active. In the other words it can't be called
585 * with non-active leaf. It also removes class from the drop list.
587 static inline void htb_deactivate(struct htb_sched *q, struct htb_class *cl)
589 BUG_TRAP(cl->prio_activity);
591 htb_deactivate_prios(q, cl);
592 cl->prio_activity = 0;
593 list_del_init(&cl->un.leaf.drop_list);
596 static int htb_enqueue(struct sk_buff *skb, struct Qdisc *sch)
599 struct htb_sched *q = qdisc_priv(sch);
600 struct htb_class *cl = htb_classify(skb, sch, &ret);
602 if (cl == HTB_DIRECT) {
603 /* enqueue to helper queue */
604 if (q->direct_queue.qlen < q->direct_qlen) {
605 __skb_queue_tail(&q->direct_queue, skb);
610 return NET_XMIT_DROP;
612 #ifdef CONFIG_NET_CLS_ACT
614 if (ret == NET_XMIT_BYPASS)
619 } else if (cl->un.leaf.q->enqueue(skb, cl->un.leaf.q) !=
623 return NET_XMIT_DROP;
625 cl->bstats.packets++;
626 cl->bstats.bytes += skb->len;
631 sch->bstats.packets++;
632 sch->bstats.bytes += skb->len;
633 return NET_XMIT_SUCCESS;
636 /* TODO: requeuing packet charges it to policers again !! */
637 static int htb_requeue(struct sk_buff *skb, struct Qdisc *sch)
639 struct htb_sched *q = qdisc_priv(sch);
640 int ret = NET_XMIT_SUCCESS;
641 struct htb_class *cl = htb_classify(skb, sch, &ret);
642 struct sk_buff *tskb;
644 if (cl == HTB_DIRECT || !cl) {
645 /* enqueue to helper queue */
646 if (q->direct_queue.qlen < q->direct_qlen && cl) {
647 __skb_queue_head(&q->direct_queue, skb);
649 __skb_queue_head(&q->direct_queue, skb);
650 tskb = __skb_dequeue_tail(&q->direct_queue);
655 } else if (cl->un.leaf.q->ops->requeue(skb, cl->un.leaf.q) !=
659 return NET_XMIT_DROP;
664 sch->qstats.requeues++;
665 return NET_XMIT_SUCCESS;
669 * htb_charge_class - charges amount "bytes" to leaf and ancestors
671 * Routine assumes that packet "bytes" long was dequeued from leaf cl
672 * borrowing from "level". It accounts bytes to ceil leaky bucket for
673 * leaf and all ancestors and to rate bucket for ancestors at levels
674 * "level" and higher. It also handles possible change of mode resulting
675 * from the update. Note that mode can also increase here (MAY_BORROW to
676 * CAN_SEND) because we can use more precise clock that event queue here.
677 * In such case we remove class from event queue first.
679 static void htb_charge_class(struct htb_sched *q, struct htb_class *cl,
680 int level, int bytes)
683 enum htb_cmode old_mode;
685 #define HTB_ACCNT(T,B,R) toks = diff + cl->T; \
686 if (toks > cl->B) toks = cl->B; \
687 toks -= L2T(cl, cl->R, bytes); \
688 if (toks <= -cl->mbuffer) toks = 1-cl->mbuffer; \
692 diff = psched_tdiff_bounded(q->now, cl->t_c, cl->mbuffer);
693 if (cl->level >= level) {
694 if (cl->level == level)
696 HTB_ACCNT(tokens, buffer, rate);
698 cl->xstats.borrows++;
699 cl->tokens += diff; /* we moved t_c; update tokens */
701 HTB_ACCNT(ctokens, cbuffer, ceil);
704 old_mode = cl->cmode;
706 htb_change_class_mode(q, cl, &diff);
707 if (old_mode != cl->cmode) {
708 if (old_mode != HTB_CAN_SEND)
709 htb_safe_rb_erase(&cl->pq_node, q->wait_pq + cl->level);
710 if (cl->cmode != HTB_CAN_SEND)
711 htb_add_to_wait_tree(q, cl, diff);
714 /* update byte stats except for leaves which are already updated */
716 cl->bstats.bytes += bytes;
717 cl->bstats.packets++;
724 * htb_do_events - make mode changes to classes at the level
726 * Scans event queue for pending events and applies them. Returns time of
727 * next pending event (0 for no event in pq).
728 * Note: Applied are events whose have cl->pq_key <= q->now.
730 static psched_time_t htb_do_events(struct htb_sched *q, int level)
734 for (i = 0; i < 500; i++) {
735 struct htb_class *cl;
737 struct rb_node *p = rb_first(&q->wait_pq[level]);
742 cl = rb_entry(p, struct htb_class, pq_node);
743 if (cl->pq_key > q->now)
746 htb_safe_rb_erase(p, q->wait_pq + level);
747 diff = psched_tdiff_bounded(q->now, cl->t_c, cl->mbuffer);
748 htb_change_class_mode(q, cl, &diff);
749 if (cl->cmode != HTB_CAN_SEND)
750 htb_add_to_wait_tree(q, cl, diff);
753 printk(KERN_WARNING "htb: too many events !\n");
754 return q->now + PSCHED_TICKS_PER_SEC / 10;
757 /* Returns class->node+prio from id-tree where classe's id is >= id. NULL
758 is no such one exists. */
759 static struct rb_node *htb_id_find_next_upper(int prio, struct rb_node *n,
762 struct rb_node *r = NULL;
764 struct htb_class *cl =
765 rb_entry(n, struct htb_class, node[prio]);
766 if (id == cl->classid)
769 if (id > cl->classid) {
780 * htb_lookup_leaf - returns next leaf class in DRR order
782 * Find leaf where current feed pointers points to.
784 static struct htb_class *htb_lookup_leaf(struct rb_root *tree, int prio,
785 struct rb_node **pptr, u32 * pid)
789 struct rb_node *root;
790 struct rb_node **pptr;
792 } stk[TC_HTB_MAXDEPTH], *sp = stk;
794 BUG_TRAP(tree->rb_node);
795 sp->root = tree->rb_node;
799 for (i = 0; i < 65535; i++) {
800 if (!*sp->pptr && *sp->pid) {
801 /* ptr was invalidated but id is valid - try to recover
802 the original or next ptr */
804 htb_id_find_next_upper(prio, sp->root, *sp->pid);
806 *sp->pid = 0; /* ptr is valid now so that remove this hint as it
807 can become out of date quickly */
808 if (!*sp->pptr) { /* we are at right end; rewind & go up */
809 *sp->pptr = sp->root;
810 while ((*sp->pptr)->rb_left)
811 *sp->pptr = (*sp->pptr)->rb_left;
817 htb_next_rb_node(sp->pptr);
820 struct htb_class *cl;
821 cl = rb_entry(*sp->pptr, struct htb_class, node[prio]);
824 (++sp)->root = cl->un.inner.feed[prio].rb_node;
825 sp->pptr = cl->un.inner.ptr + prio;
826 sp->pid = cl->un.inner.last_ptr_id + prio;
833 /* dequeues packet at given priority and level; call only if
834 you are sure that there is active class at prio/level */
835 static struct sk_buff *htb_dequeue_tree(struct htb_sched *q, int prio,
838 struct sk_buff *skb = NULL;
839 struct htb_class *cl, *start;
840 /* look initial class up in the row */
841 start = cl = htb_lookup_leaf(q->row[level] + prio, prio,
842 q->ptr[level] + prio,
843 q->last_ptr_id[level] + prio);
851 /* class can be empty - it is unlikely but can be true if leaf
852 qdisc drops packets in enqueue routine or if someone used
853 graft operation on the leaf since last dequeue;
854 simply deactivate and skip such class */
855 if (unlikely(cl->un.leaf.q->q.qlen == 0)) {
856 struct htb_class *next;
857 htb_deactivate(q, cl);
859 /* row/level might become empty */
860 if ((q->row_mask[level] & (1 << prio)) == 0)
863 next = htb_lookup_leaf(q->row[level] + prio,
864 prio, q->ptr[level] + prio,
865 q->last_ptr_id[level] + prio);
867 if (cl == start) /* fix start if we just deleted it */
873 skb = cl->un.leaf.q->dequeue(cl->un.leaf.q);
874 if (likely(skb != NULL))
878 "htb: class %X isn't work conserving ?!\n",
883 htb_next_rb_node((level ? cl->parent->un.inner.ptr : q->
885 cl = htb_lookup_leaf(q->row[level] + prio, prio,
886 q->ptr[level] + prio,
887 q->last_ptr_id[level] + prio);
889 } while (cl != start);
891 if (likely(skb != NULL)) {
892 if ((cl->un.leaf.deficit[level] -= skb->len) < 0) {
893 cl->un.leaf.deficit[level] += cl->un.leaf.quantum;
894 htb_next_rb_node((level ? cl->parent->un.inner.ptr : q->
897 /* this used to be after charge_class but this constelation
898 gives us slightly better performance */
899 if (!cl->un.leaf.q->q.qlen)
900 htb_deactivate(q, cl);
901 htb_charge_class(q, cl, level, skb->len);
906 static struct sk_buff *htb_dequeue(struct Qdisc *sch)
908 struct sk_buff *skb = NULL;
909 struct htb_sched *q = qdisc_priv(sch);
911 psched_time_t next_event;
913 /* try to dequeue direct packets as high prio (!) to minimize cpu work */
914 skb = __skb_dequeue(&q->direct_queue);
916 sch->flags &= ~TCQ_F_THROTTLED;
923 q->now = psched_get_time();
925 next_event = q->now + 5 * PSCHED_TICKS_PER_SEC;
927 for (level = 0; level < TC_HTB_MAXDEPTH; level++) {
928 /* common case optimization - skip event handler quickly */
932 if (q->now >= q->near_ev_cache[level]) {
933 event = htb_do_events(q, level);
935 event = q->now + PSCHED_TICKS_PER_SEC;
936 q->near_ev_cache[level] = event;
938 event = q->near_ev_cache[level];
940 if (event && next_event > event)
943 m = ~q->row_mask[level];
944 while (m != (int)(-1)) {
947 skb = htb_dequeue_tree(q, prio, level);
948 if (likely(skb != NULL)) {
950 sch->flags &= ~TCQ_F_THROTTLED;
955 sch->qstats.overlimits++;
956 qdisc_watchdog_schedule(&q->watchdog, next_event);
961 /* try to drop from each class (by prio) until one succeed */
962 static unsigned int htb_drop(struct Qdisc *sch)
964 struct htb_sched *q = qdisc_priv(sch);
967 for (prio = TC_HTB_NUMPRIO - 1; prio >= 0; prio--) {
969 list_for_each(p, q->drops + prio) {
970 struct htb_class *cl = list_entry(p, struct htb_class,
973 if (cl->un.leaf.q->ops->drop &&
974 (len = cl->un.leaf.q->ops->drop(cl->un.leaf.q))) {
976 if (!cl->un.leaf.q->q.qlen)
977 htb_deactivate(q, cl);
985 /* reset all classes */
986 /* always caled under BH & queue lock */
987 static void htb_reset(struct Qdisc *sch)
989 struct htb_sched *q = qdisc_priv(sch);
992 for (i = 0; i < HTB_HSIZE; i++) {
993 struct hlist_node *p;
994 struct htb_class *cl;
996 hlist_for_each_entry(cl, p, q->hash + i, hlist) {
998 memset(&cl->un.inner, 0, sizeof(cl->un.inner));
1001 qdisc_reset(cl->un.leaf.q);
1002 INIT_LIST_HEAD(&cl->un.leaf.drop_list);
1004 cl->prio_activity = 0;
1005 cl->cmode = HTB_CAN_SEND;
1009 qdisc_watchdog_cancel(&q->watchdog);
1010 __skb_queue_purge(&q->direct_queue);
1012 memset(q->row, 0, sizeof(q->row));
1013 memset(q->row_mask, 0, sizeof(q->row_mask));
1014 memset(q->wait_pq, 0, sizeof(q->wait_pq));
1015 memset(q->ptr, 0, sizeof(q->ptr));
1016 for (i = 0; i < TC_HTB_NUMPRIO; i++)
1017 INIT_LIST_HEAD(q->drops + i);
1020 static int htb_init(struct Qdisc *sch, struct rtattr *opt)
1022 struct htb_sched *q = qdisc_priv(sch);
1023 struct rtattr *tb[TCA_HTB_INIT];
1024 struct tc_htb_glob *gopt;
1026 if (!opt || rtattr_parse_nested(tb, TCA_HTB_INIT, opt) ||
1027 tb[TCA_HTB_INIT - 1] == NULL ||
1028 RTA_PAYLOAD(tb[TCA_HTB_INIT - 1]) < sizeof(*gopt)) {
1029 printk(KERN_ERR "HTB: hey probably you have bad tc tool ?\n");
1032 gopt = RTA_DATA(tb[TCA_HTB_INIT - 1]);
1033 if (gopt->version != HTB_VER >> 16) {
1035 "HTB: need tc/htb version %d (minor is %d), you have %d\n",
1036 HTB_VER >> 16, HTB_VER & 0xffff, gopt->version);
1040 INIT_LIST_HEAD(&q->root);
1041 for (i = 0; i < HTB_HSIZE; i++)
1042 INIT_HLIST_HEAD(q->hash + i);
1043 for (i = 0; i < TC_HTB_NUMPRIO; i++)
1044 INIT_LIST_HEAD(q->drops + i);
1046 qdisc_watchdog_init(&q->watchdog, sch);
1047 skb_queue_head_init(&q->direct_queue);
1049 q->direct_qlen = sch->dev->tx_queue_len;
1050 if (q->direct_qlen < 2) /* some devices have zero tx_queue_len */
1053 if ((q->rate2quantum = gopt->rate2quantum) < 1)
1054 q->rate2quantum = 1;
1055 q->defcls = gopt->defcls;
1060 static int htb_dump(struct Qdisc *sch, struct sk_buff *skb)
1062 struct htb_sched *q = qdisc_priv(sch);
1063 unsigned char *b = skb_tail_pointer(skb);
1065 struct tc_htb_glob gopt;
1066 spin_lock_bh(&sch->dev->queue_lock);
1067 gopt.direct_pkts = q->direct_pkts;
1069 gopt.version = HTB_VER;
1070 gopt.rate2quantum = q->rate2quantum;
1071 gopt.defcls = q->defcls;
1073 rta = (struct rtattr *)b;
1074 RTA_PUT(skb, TCA_OPTIONS, 0, NULL);
1075 RTA_PUT(skb, TCA_HTB_INIT, sizeof(gopt), &gopt);
1076 rta->rta_len = skb_tail_pointer(skb) - b;
1077 spin_unlock_bh(&sch->dev->queue_lock);
1080 spin_unlock_bh(&sch->dev->queue_lock);
1081 nlmsg_trim(skb, skb_tail_pointer(skb));
1085 static int htb_dump_class(struct Qdisc *sch, unsigned long arg,
1086 struct sk_buff *skb, struct tcmsg *tcm)
1088 struct htb_class *cl = (struct htb_class *)arg;
1089 unsigned char *b = skb_tail_pointer(skb);
1091 struct tc_htb_opt opt;
1093 spin_lock_bh(&sch->dev->queue_lock);
1094 tcm->tcm_parent = cl->parent ? cl->parent->classid : TC_H_ROOT;
1095 tcm->tcm_handle = cl->classid;
1096 if (!cl->level && cl->un.leaf.q)
1097 tcm->tcm_info = cl->un.leaf.q->handle;
1099 rta = (struct rtattr *)b;
1100 RTA_PUT(skb, TCA_OPTIONS, 0, NULL);
1102 memset(&opt, 0, sizeof(opt));
1104 opt.rate = cl->rate->rate;
1105 opt.buffer = cl->buffer;
1106 opt.ceil = cl->ceil->rate;
1107 opt.cbuffer = cl->cbuffer;
1108 opt.quantum = cl->un.leaf.quantum;
1109 opt.prio = cl->un.leaf.prio;
1110 opt.level = cl->level;
1111 RTA_PUT(skb, TCA_HTB_PARMS, sizeof(opt), &opt);
1112 rta->rta_len = skb_tail_pointer(skb) - b;
1113 spin_unlock_bh(&sch->dev->queue_lock);
1116 spin_unlock_bh(&sch->dev->queue_lock);
1122 htb_dump_class_stats(struct Qdisc *sch, unsigned long arg, struct gnet_dump *d)
1124 struct htb_class *cl = (struct htb_class *)arg;
1126 if (!cl->level && cl->un.leaf.q)
1127 cl->qstats.qlen = cl->un.leaf.q->q.qlen;
1128 cl->xstats.tokens = cl->tokens;
1129 cl->xstats.ctokens = cl->ctokens;
1131 if (gnet_stats_copy_basic(d, &cl->bstats) < 0 ||
1132 gnet_stats_copy_rate_est(d, &cl->rate_est) < 0 ||
1133 gnet_stats_copy_queue(d, &cl->qstats) < 0)
1136 return gnet_stats_copy_app(d, &cl->xstats, sizeof(cl->xstats));
1139 static int htb_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
1142 struct htb_class *cl = (struct htb_class *)arg;
1144 if (cl && !cl->level) {
1146 (new = qdisc_create_dflt(sch->dev, &pfifo_qdisc_ops,
1151 if ((*old = xchg(&cl->un.leaf.q, new)) != NULL) {
1152 qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
1155 sch_tree_unlock(sch);
1161 static struct Qdisc *htb_leaf(struct Qdisc *sch, unsigned long arg)
1163 struct htb_class *cl = (struct htb_class *)arg;
1164 return (cl && !cl->level) ? cl->un.leaf.q : NULL;
1167 static void htb_qlen_notify(struct Qdisc *sch, unsigned long arg)
1169 struct htb_class *cl = (struct htb_class *)arg;
1171 if (cl->un.leaf.q->q.qlen == 0)
1172 htb_deactivate(qdisc_priv(sch), cl);
1175 static unsigned long htb_get(struct Qdisc *sch, u32 classid)
1177 struct htb_class *cl = htb_find(classid, sch);
1180 return (unsigned long)cl;
1183 static inline int htb_parent_last_child(struct htb_class *cl)
1186 /* the root class */
1189 if (!(cl->parent->children.next == &cl->sibling &&
1190 cl->parent->children.prev == &cl->sibling))
1191 /* not the last child */
1197 static void htb_parent_to_leaf(struct htb_class *cl, struct Qdisc *new_q)
1199 struct htb_class *parent = cl->parent;
1201 BUG_TRAP(!cl->level && cl->un.leaf.q && !cl->prio_activity);
1204 memset(&parent->un.inner, 0, sizeof(parent->un.inner));
1205 INIT_LIST_HEAD(&parent->un.leaf.drop_list);
1206 parent->un.leaf.q = new_q ? new_q : &noop_qdisc;
1207 parent->un.leaf.quantum = parent->quantum;
1208 parent->un.leaf.prio = parent->prio;
1209 parent->tokens = parent->buffer;
1210 parent->ctokens = parent->cbuffer;
1211 parent->t_c = psched_get_time();
1212 parent->cmode = HTB_CAN_SEND;
1215 static void htb_destroy_class(struct Qdisc *sch, struct htb_class *cl)
1217 struct htb_sched *q = qdisc_priv(sch);
1220 BUG_TRAP(cl->un.leaf.q);
1221 qdisc_destroy(cl->un.leaf.q);
1223 gen_kill_estimator(&cl->bstats, &cl->rate_est);
1224 qdisc_put_rtab(cl->rate);
1225 qdisc_put_rtab(cl->ceil);
1227 tcf_destroy_chain(cl->filter_list);
1229 while (!list_empty(&cl->children))
1230 htb_destroy_class(sch, list_entry(cl->children.next,
1231 struct htb_class, sibling));
1233 /* note: this delete may happen twice (see htb_delete) */
1234 hlist_del_init(&cl->hlist);
1235 list_del(&cl->sibling);
1237 if (cl->prio_activity)
1238 htb_deactivate(q, cl);
1240 if (cl->cmode != HTB_CAN_SEND)
1241 htb_safe_rb_erase(&cl->pq_node, q->wait_pq + cl->level);
1246 /* always caled under BH & queue lock */
1247 static void htb_destroy(struct Qdisc *sch)
1249 struct htb_sched *q = qdisc_priv(sch);
1251 qdisc_watchdog_cancel(&q->watchdog);
1252 /* This line used to be after htb_destroy_class call below
1253 and surprisingly it worked in 2.4. But it must precede it
1254 because filter need its target class alive to be able to call
1255 unbind_filter on it (without Oops). */
1256 tcf_destroy_chain(q->filter_list);
1258 while (!list_empty(&q->root))
1259 htb_destroy_class(sch, list_entry(q->root.next,
1260 struct htb_class, sibling));
1262 __skb_queue_purge(&q->direct_queue);
1265 static int htb_delete(struct Qdisc *sch, unsigned long arg)
1267 struct htb_sched *q = qdisc_priv(sch);
1268 struct htb_class *cl = (struct htb_class *)arg;
1270 struct Qdisc *new_q = NULL;
1273 // TODO: why don't allow to delete subtree ? references ? does
1274 // tc subsys quarantee us that in htb_destroy it holds no class
1275 // refs so that we can remove children safely there ?
1276 if (!list_empty(&cl->children) || cl->filter_cnt)
1279 if (!cl->level && htb_parent_last_child(cl)) {
1280 new_q = qdisc_create_dflt(sch->dev, &pfifo_qdisc_ops,
1281 cl->parent->classid);
1288 qlen = cl->un.leaf.q->q.qlen;
1289 qdisc_reset(cl->un.leaf.q);
1290 qdisc_tree_decrease_qlen(cl->un.leaf.q, qlen);
1293 /* delete from hash and active; remainder in destroy_class */
1294 hlist_del_init(&cl->hlist);
1296 if (cl->prio_activity)
1297 htb_deactivate(q, cl);
1300 htb_parent_to_leaf(cl, new_q);
1302 if (--cl->refcnt == 0)
1303 htb_destroy_class(sch, cl);
1305 sch_tree_unlock(sch);
1309 static void htb_put(struct Qdisc *sch, unsigned long arg)
1311 struct htb_class *cl = (struct htb_class *)arg;
1313 if (--cl->refcnt == 0)
1314 htb_destroy_class(sch, cl);
1317 static int htb_change_class(struct Qdisc *sch, u32 classid,
1318 u32 parentid, struct rtattr **tca,
1322 struct htb_sched *q = qdisc_priv(sch);
1323 struct htb_class *cl = (struct htb_class *)*arg, *parent;
1324 struct rtattr *opt = tca[TCA_OPTIONS - 1];
1325 struct qdisc_rate_table *rtab = NULL, *ctab = NULL;
1326 struct rtattr *tb[TCA_HTB_RTAB];
1327 struct tc_htb_opt *hopt;
1329 /* extract all subattrs from opt attr */
1330 if (!opt || rtattr_parse_nested(tb, TCA_HTB_RTAB, opt) ||
1331 tb[TCA_HTB_PARMS - 1] == NULL ||
1332 RTA_PAYLOAD(tb[TCA_HTB_PARMS - 1]) < sizeof(*hopt))
1335 parent = parentid == TC_H_ROOT ? NULL : htb_find(parentid, sch);
1337 hopt = RTA_DATA(tb[TCA_HTB_PARMS - 1]);
1339 rtab = qdisc_get_rtab(&hopt->rate, tb[TCA_HTB_RTAB - 1]);
1340 ctab = qdisc_get_rtab(&hopt->ceil, tb[TCA_HTB_CTAB - 1]);
1344 if (!cl) { /* new class */
1345 struct Qdisc *new_q;
1349 struct gnet_estimator opt;
1352 .rta_len = RTA_LENGTH(sizeof(est.opt)),
1353 .rta_type = TCA_RATE,
1356 /* 4s interval, 16s averaging constant */
1362 /* check for valid classid */
1363 if (!classid || TC_H_MAJ(classid ^ sch->handle)
1364 || htb_find(classid, sch))
1367 /* check maximal depth */
1368 if (parent && parent->parent && parent->parent->level < 2) {
1369 printk(KERN_ERR "htb: tree is too deep\n");
1373 if ((cl = kzalloc(sizeof(*cl), GFP_KERNEL)) == NULL)
1376 gen_new_estimator(&cl->bstats, &cl->rate_est,
1377 &sch->dev->queue_lock,
1378 tca[TCA_RATE-1] ? : &est.rta);
1380 INIT_LIST_HEAD(&cl->sibling);
1381 INIT_HLIST_NODE(&cl->hlist);
1382 INIT_LIST_HEAD(&cl->children);
1383 INIT_LIST_HEAD(&cl->un.leaf.drop_list);
1384 RB_CLEAR_NODE(&cl->pq_node);
1386 for (prio = 0; prio < TC_HTB_NUMPRIO; prio++)
1387 RB_CLEAR_NODE(&cl->node[prio]);
1389 /* create leaf qdisc early because it uses kmalloc(GFP_KERNEL)
1390 so that can't be used inside of sch_tree_lock
1391 -- thanks to Karlis Peisenieks */
1392 new_q = qdisc_create_dflt(sch->dev, &pfifo_qdisc_ops, classid);
1394 if (parent && !parent->level) {
1395 unsigned int qlen = parent->un.leaf.q->q.qlen;
1397 /* turn parent into inner node */
1398 qdisc_reset(parent->un.leaf.q);
1399 qdisc_tree_decrease_qlen(parent->un.leaf.q, qlen);
1400 qdisc_destroy(parent->un.leaf.q);
1401 if (parent->prio_activity)
1402 htb_deactivate(q, parent);
1404 /* remove from evt list because of level change */
1405 if (parent->cmode != HTB_CAN_SEND) {
1406 htb_safe_rb_erase(&parent->pq_node, q->wait_pq);
1407 parent->cmode = HTB_CAN_SEND;
1409 parent->level = (parent->parent ? parent->parent->level
1410 : TC_HTB_MAXDEPTH) - 1;
1411 memset(&parent->un.inner, 0, sizeof(parent->un.inner));
1413 /* leaf (we) needs elementary qdisc */
1414 cl->un.leaf.q = new_q ? new_q : &noop_qdisc;
1416 cl->classid = classid;
1417 cl->parent = parent;
1419 /* set class to be in HTB_CAN_SEND state */
1420 cl->tokens = hopt->buffer;
1421 cl->ctokens = hopt->cbuffer;
1422 cl->mbuffer = 60 * PSCHED_TICKS_PER_SEC; /* 1min */
1423 cl->t_c = psched_get_time();
1424 cl->cmode = HTB_CAN_SEND;
1426 /* attach to the hash list and parent's family */
1427 hlist_add_head(&cl->hlist, q->hash + htb_hash(classid));
1428 list_add_tail(&cl->sibling,
1429 parent ? &parent->children : &q->root);
1431 if (tca[TCA_RATE-1])
1432 gen_replace_estimator(&cl->bstats, &cl->rate_est,
1433 &sch->dev->queue_lock,
1438 /* it used to be a nasty bug here, we have to check that node
1439 is really leaf before changing cl->un.leaf ! */
1441 cl->un.leaf.quantum = rtab->rate.rate / q->rate2quantum;
1442 if (!hopt->quantum && cl->un.leaf.quantum < 1000) {
1444 "HTB: quantum of class %X is small. Consider r2q change.\n",
1446 cl->un.leaf.quantum = 1000;
1448 if (!hopt->quantum && cl->un.leaf.quantum > 200000) {
1450 "HTB: quantum of class %X is big. Consider r2q change.\n",
1452 cl->un.leaf.quantum = 200000;
1455 cl->un.leaf.quantum = hopt->quantum;
1456 if ((cl->un.leaf.prio = hopt->prio) >= TC_HTB_NUMPRIO)
1457 cl->un.leaf.prio = TC_HTB_NUMPRIO - 1;
1459 /* backup for htb_parent_to_leaf */
1460 cl->quantum = cl->un.leaf.quantum;
1461 cl->prio = cl->un.leaf.prio;
1464 cl->buffer = hopt->buffer;
1465 cl->cbuffer = hopt->cbuffer;
1467 qdisc_put_rtab(cl->rate);
1470 qdisc_put_rtab(cl->ceil);
1472 sch_tree_unlock(sch);
1474 *arg = (unsigned long)cl;
1479 qdisc_put_rtab(rtab);
1481 qdisc_put_rtab(ctab);
1485 static struct tcf_proto **htb_find_tcf(struct Qdisc *sch, unsigned long arg)
1487 struct htb_sched *q = qdisc_priv(sch);
1488 struct htb_class *cl = (struct htb_class *)arg;
1489 struct tcf_proto **fl = cl ? &cl->filter_list : &q->filter_list;
1494 static unsigned long htb_bind_filter(struct Qdisc *sch, unsigned long parent,
1497 struct htb_sched *q = qdisc_priv(sch);
1498 struct htb_class *cl = htb_find(classid, sch);
1500 /*if (cl && !cl->level) return 0;
1501 The line above used to be there to prevent attaching filters to
1502 leaves. But at least tc_index filter uses this just to get class
1503 for other reasons so that we have to allow for it.
1505 19.6.2002 As Werner explained it is ok - bind filter is just
1506 another way to "lock" the class - unlike "get" this lock can
1507 be broken by class during destroy IIUC.
1513 return (unsigned long)cl;
1516 static void htb_unbind_filter(struct Qdisc *sch, unsigned long arg)
1518 struct htb_sched *q = qdisc_priv(sch);
1519 struct htb_class *cl = (struct htb_class *)arg;
1527 static void htb_walk(struct Qdisc *sch, struct qdisc_walker *arg)
1529 struct htb_sched *q = qdisc_priv(sch);
1535 for (i = 0; i < HTB_HSIZE; i++) {
1536 struct hlist_node *p;
1537 struct htb_class *cl;
1539 hlist_for_each_entry(cl, p, q->hash + i, hlist) {
1540 if (arg->count < arg->skip) {
1544 if (arg->fn(sch, (unsigned long)cl, arg) < 0) {
1553 static struct Qdisc_class_ops htb_class_ops = {
1556 .qlen_notify = htb_qlen_notify,
1559 .change = htb_change_class,
1560 .delete = htb_delete,
1562 .tcf_chain = htb_find_tcf,
1563 .bind_tcf = htb_bind_filter,
1564 .unbind_tcf = htb_unbind_filter,
1565 .dump = htb_dump_class,
1566 .dump_stats = htb_dump_class_stats,
1569 static struct Qdisc_ops htb_qdisc_ops = {
1571 .cl_ops = &htb_class_ops,
1573 .priv_size = sizeof(struct htb_sched),
1574 .enqueue = htb_enqueue,
1575 .dequeue = htb_dequeue,
1576 .requeue = htb_requeue,
1580 .destroy = htb_destroy,
1581 .change = NULL /* htb_change */,
1583 .owner = THIS_MODULE,
1586 static int __init htb_module_init(void)
1588 return register_qdisc(&htb_qdisc_ops);
1590 static void __exit htb_module_exit(void)
1592 unregister_qdisc(&htb_qdisc_ops);
1595 module_init(htb_module_init)
1596 module_exit(htb_module_exit)
1597 MODULE_LICENSE("GPL");