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 #include <linux/module.h>
29 #include <linux/moduleparam.h>
30 #include <linux/types.h>
31 #include <linux/kernel.h>
32 #include <linux/string.h>
33 #include <linux/errno.h>
34 #include <linux/skbuff.h>
35 #include <linux/list.h>
36 #include <linux/compiler.h>
37 #include <linux/rbtree.h>
38 #include <net/netlink.h>
39 #include <net/pkt_sched.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 /* used internaly to keep status of single class */
67 HTB_CANT_SEND, /* class can't send and can't borrow */
68 HTB_MAY_BORROW, /* class can't send but may borrow */
69 HTB_CAN_SEND /* class can send */
72 /* interior & leaf nodes; props specific to leaves are marked L: */
74 struct Qdisc_class_common common;
75 /* general class parameters */
76 struct gnet_stats_basic bstats;
77 struct gnet_stats_queue qstats;
78 struct gnet_stats_rate_est rate_est;
79 struct tc_htb_xstats xstats; /* our special stats */
80 int refcnt; /* usage count of this class */
83 int level; /* our level (see above) */
84 unsigned int children;
85 struct htb_class *parent; /* parent class */
88 struct htb_class_leaf {
93 int deficit[TC_HTB_MAXDEPTH];
94 struct list_head drop_list;
96 struct htb_class_inner {
97 struct rb_root feed[TC_HTB_NUMPRIO]; /* feed trees */
98 struct rb_node *ptr[TC_HTB_NUMPRIO]; /* current class ptr */
99 /* When class changes from state 1->2 and disconnects from
100 parent's feed then we lost ptr value and start from the
101 first child again. Here we store classid of the
102 last valid ptr (used when ptr is NULL). */
103 u32 last_ptr_id[TC_HTB_NUMPRIO];
106 struct rb_node node[TC_HTB_NUMPRIO]; /* node for self or feed tree */
107 struct rb_node pq_node; /* node for event queue */
108 psched_time_t pq_key;
110 int prio_activity; /* for which prios are we active */
111 enum htb_cmode cmode; /* current mode of the class */
113 /* class attached filters */
114 struct tcf_proto *filter_list;
117 int warned; /* only one warning about non work conserving .. */
119 /* token bucket parameters */
120 struct qdisc_rate_table *rate; /* rate table of the class itself */
121 struct qdisc_rate_table *ceil; /* ceiling rate (limits borrows too) */
122 long buffer, cbuffer; /* token bucket depth/rate */
123 psched_tdiff_t mbuffer; /* max wait time */
124 long tokens, ctokens; /* current number of tokens */
125 psched_time_t t_c; /* checkpoint time */
127 int prio; /* For parent to leaf return possible here */
128 int quantum; /* we do backup. Finally full replacement */
129 /* of un.leaf originals should be done. */
132 static inline long L2T(struct htb_class *cl, struct qdisc_rate_table *rate,
135 long result = qdisc_l2t(rate, size);
140 struct Qdisc_class_hash clhash;
141 struct list_head drops[TC_HTB_NUMPRIO];/* active leaves (for drops) */
143 /* self list - roots of self generating tree */
144 struct rb_root row[TC_HTB_MAXDEPTH][TC_HTB_NUMPRIO];
145 int row_mask[TC_HTB_MAXDEPTH];
146 struct rb_node *ptr[TC_HTB_MAXDEPTH][TC_HTB_NUMPRIO];
147 u32 last_ptr_id[TC_HTB_MAXDEPTH][TC_HTB_NUMPRIO];
149 /* self wait list - roots of wait PQs per row */
150 struct rb_root wait_pq[TC_HTB_MAXDEPTH];
152 /* time of nearest event per level (row) */
153 psched_time_t near_ev_cache[TC_HTB_MAXDEPTH];
155 /* whether we hit non-work conserving class during this dequeue; we use */
156 int nwc_hit; /* this to disable mindelay complaint in dequeue */
158 int defcls; /* class where unclassified flows go to */
160 /* filters for qdisc itself */
161 struct tcf_proto *filter_list;
163 int rate2quantum; /* quant = rate / rate2quantum */
164 psched_time_t now; /* cached dequeue time */
165 struct qdisc_watchdog watchdog;
167 /* non shaped skbs; let them go directly thru */
168 struct sk_buff_head direct_queue;
169 int direct_qlen; /* max qlen of above */
174 /* find class in global hash table using given handle */
175 static inline struct htb_class *htb_find(u32 handle, struct Qdisc *sch)
177 struct htb_sched *q = qdisc_priv(sch);
178 struct Qdisc_class_common *clc;
180 clc = qdisc_class_find(&q->clhash, handle);
183 return container_of(clc, struct htb_class, common);
187 * htb_classify - classify a packet into class
189 * It returns NULL if the packet should be dropped or -1 if the packet
190 * should be passed directly thru. In all other cases leaf class is returned.
191 * We allow direct class selection by classid in priority. The we examine
192 * filters in qdisc and in inner nodes (if higher filter points to the inner
193 * node). If we end up with classid MAJOR:0 we enqueue the skb into special
194 * internal fifo (direct). These packets then go directly thru. If we still
195 * have no valid leaf we try to use MAJOR:default leaf. It still unsuccessfull
196 * then finish and return direct queue.
198 #define HTB_DIRECT (struct htb_class*)-1
200 static struct htb_class *htb_classify(struct sk_buff *skb, struct Qdisc *sch,
203 struct htb_sched *q = qdisc_priv(sch);
204 struct htb_class *cl;
205 struct tcf_result res;
206 struct tcf_proto *tcf;
209 /* allow to select class by setting skb->priority to valid classid;
210 note that nfmark can be used too by attaching filter fw with no
212 if (skb->priority == sch->handle)
213 return HTB_DIRECT; /* X:0 (direct flow) selected */
214 if ((cl = htb_find(skb->priority, sch)) != NULL && cl->level == 0)
217 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
218 tcf = q->filter_list;
219 while (tcf && (result = tc_classify(skb, tcf, &res)) >= 0) {
220 #ifdef CONFIG_NET_CLS_ACT
224 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
229 if ((cl = (void *)res.class) == NULL) {
230 if (res.classid == sch->handle)
231 return HTB_DIRECT; /* X:0 (direct flow) */
232 if ((cl = htb_find(res.classid, sch)) == NULL)
233 break; /* filter selected invalid classid */
236 return cl; /* we hit leaf; return it */
238 /* we have got inner class; apply inner filter chain */
239 tcf = cl->filter_list;
241 /* classification failed; try to use default class */
242 cl = htb_find(TC_H_MAKE(TC_H_MAJ(sch->handle), q->defcls), sch);
243 if (!cl || cl->level)
244 return HTB_DIRECT; /* bad default .. this is safe bet */
249 * htb_add_to_id_tree - adds class to the round robin list
251 * Routine adds class to the list (actually tree) sorted by classid.
252 * Make sure that class is not already on such list for given prio.
254 static void htb_add_to_id_tree(struct rb_root *root,
255 struct htb_class *cl, int prio)
257 struct rb_node **p = &root->rb_node, *parent = NULL;
262 c = rb_entry(parent, struct htb_class, node[prio]);
264 if (cl->common.classid > c->common.classid)
265 p = &parent->rb_right;
267 p = &parent->rb_left;
269 rb_link_node(&cl->node[prio], parent, p);
270 rb_insert_color(&cl->node[prio], root);
274 * htb_add_to_wait_tree - adds class to the event queue with delay
276 * The class is added to priority event queue to indicate that class will
277 * change its mode in cl->pq_key microseconds. Make sure that class is not
278 * already in the queue.
280 static void htb_add_to_wait_tree(struct htb_sched *q,
281 struct htb_class *cl, long delay)
283 struct rb_node **p = &q->wait_pq[cl->level].rb_node, *parent = NULL;
285 cl->pq_key = q->now + delay;
286 if (cl->pq_key == q->now)
289 /* update the nearest event cache */
290 if (q->near_ev_cache[cl->level] > cl->pq_key)
291 q->near_ev_cache[cl->level] = cl->pq_key;
296 c = rb_entry(parent, struct htb_class, pq_node);
297 if (cl->pq_key >= c->pq_key)
298 p = &parent->rb_right;
300 p = &parent->rb_left;
302 rb_link_node(&cl->pq_node, parent, p);
303 rb_insert_color(&cl->pq_node, &q->wait_pq[cl->level]);
307 * htb_next_rb_node - finds next node in binary tree
309 * When we are past last key we return NULL.
310 * Average complexity is 2 steps per call.
312 static inline void htb_next_rb_node(struct rb_node **n)
318 * htb_add_class_to_row - add class to its row
320 * The class is added to row at priorities marked in mask.
321 * It does nothing if mask == 0.
323 static inline void htb_add_class_to_row(struct htb_sched *q,
324 struct htb_class *cl, int mask)
326 q->row_mask[cl->level] |= mask;
328 int prio = ffz(~mask);
329 mask &= ~(1 << prio);
330 htb_add_to_id_tree(q->row[cl->level] + prio, cl, prio);
334 /* If this triggers, it is a bug in this code, but it need not be fatal */
335 static void htb_safe_rb_erase(struct rb_node *rb, struct rb_root *root)
337 if (RB_EMPTY_NODE(rb)) {
347 * htb_remove_class_from_row - removes class from its row
349 * The class is removed from row at priorities marked in mask.
350 * It does nothing if mask == 0.
352 static inline void htb_remove_class_from_row(struct htb_sched *q,
353 struct htb_class *cl, int mask)
358 int prio = ffz(~mask);
360 mask &= ~(1 << prio);
361 if (q->ptr[cl->level][prio] == cl->node + prio)
362 htb_next_rb_node(q->ptr[cl->level] + prio);
364 htb_safe_rb_erase(cl->node + prio, q->row[cl->level] + prio);
365 if (!q->row[cl->level][prio].rb_node)
368 q->row_mask[cl->level] &= ~m;
372 * htb_activate_prios - creates active classe's feed chain
374 * The class is connected to ancestors and/or appropriate rows
375 * for priorities it is participating on. cl->cmode must be new
376 * (activated) mode. It does nothing if cl->prio_activity == 0.
378 static void htb_activate_prios(struct htb_sched *q, struct htb_class *cl)
380 struct htb_class *p = cl->parent;
381 long m, mask = cl->prio_activity;
383 while (cl->cmode == HTB_MAY_BORROW && p && mask) {
389 if (p->un.inner.feed[prio].rb_node)
390 /* parent already has its feed in use so that
391 reset bit in mask as parent is already ok */
392 mask &= ~(1 << prio);
394 htb_add_to_id_tree(p->un.inner.feed + prio, cl, prio);
396 p->prio_activity |= mask;
401 if (cl->cmode == HTB_CAN_SEND && mask)
402 htb_add_class_to_row(q, cl, mask);
406 * htb_deactivate_prios - remove class from feed chain
408 * cl->cmode must represent old mode (before deactivation). It does
409 * nothing if cl->prio_activity == 0. Class is removed from all feed
412 static void htb_deactivate_prios(struct htb_sched *q, struct htb_class *cl)
414 struct htb_class *p = cl->parent;
415 long m, mask = cl->prio_activity;
417 while (cl->cmode == HTB_MAY_BORROW && p && mask) {
424 if (p->un.inner.ptr[prio] == cl->node + prio) {
425 /* we are removing child which is pointed to from
426 parent feed - forget the pointer but remember
428 p->un.inner.last_ptr_id[prio] = cl->common.classid;
429 p->un.inner.ptr[prio] = NULL;
432 htb_safe_rb_erase(cl->node + prio, p->un.inner.feed + prio);
434 if (!p->un.inner.feed[prio].rb_node)
438 p->prio_activity &= ~mask;
443 if (cl->cmode == HTB_CAN_SEND && mask)
444 htb_remove_class_from_row(q, cl, mask);
447 static inline long htb_lowater(const struct htb_class *cl)
450 return cl->cmode != HTB_CANT_SEND ? -cl->cbuffer : 0;
454 static inline long htb_hiwater(const struct htb_class *cl)
457 return cl->cmode == HTB_CAN_SEND ? -cl->buffer : 0;
464 * htb_class_mode - computes and returns current class mode
466 * It computes cl's mode at time cl->t_c+diff and returns it. If mode
467 * is not HTB_CAN_SEND then cl->pq_key is updated to time difference
468 * from now to time when cl will change its state.
469 * Also it is worth to note that class mode doesn't change simply
470 * at cl->{c,}tokens == 0 but there can rather be hysteresis of
471 * 0 .. -cl->{c,}buffer range. It is meant to limit number of
472 * mode transitions per time unit. The speed gain is about 1/6.
474 static inline enum htb_cmode
475 htb_class_mode(struct htb_class *cl, long *diff)
479 if ((toks = (cl->ctokens + *diff)) < htb_lowater(cl)) {
481 return HTB_CANT_SEND;
484 if ((toks = (cl->tokens + *diff)) >= htb_hiwater(cl))
488 return HTB_MAY_BORROW;
492 * htb_change_class_mode - changes classe's mode
494 * This should be the only way how to change classe's mode under normal
495 * cirsumstances. Routine will update feed lists linkage, change mode
496 * and add class to the wait event queue if appropriate. New mode should
497 * be different from old one and cl->pq_key has to be valid if changing
498 * to mode other than HTB_CAN_SEND (see htb_add_to_wait_tree).
501 htb_change_class_mode(struct htb_sched *q, struct htb_class *cl, long *diff)
503 enum htb_cmode new_mode = htb_class_mode(cl, diff);
505 if (new_mode == cl->cmode)
508 if (cl->prio_activity) { /* not necessary: speed optimization */
509 if (cl->cmode != HTB_CANT_SEND)
510 htb_deactivate_prios(q, cl);
511 cl->cmode = new_mode;
512 if (new_mode != HTB_CANT_SEND)
513 htb_activate_prios(q, cl);
515 cl->cmode = new_mode;
519 * htb_activate - inserts leaf cl into appropriate active feeds
521 * Routine learns (new) priority of leaf and activates feed chain
522 * for the prio. It can be called on already active leaf safely.
523 * It also adds leaf into droplist.
525 static inline void htb_activate(struct htb_sched *q, struct htb_class *cl)
527 WARN_ON(cl->level || !cl->un.leaf.q || !cl->un.leaf.q->q.qlen);
529 if (!cl->prio_activity) {
530 cl->prio_activity = 1 << (cl->un.leaf.aprio = cl->un.leaf.prio);
531 htb_activate_prios(q, cl);
532 list_add_tail(&cl->un.leaf.drop_list,
533 q->drops + cl->un.leaf.aprio);
538 * htb_deactivate - remove leaf cl from active feeds
540 * Make sure that leaf is active. In the other words it can't be called
541 * with non-active leaf. It also removes class from the drop list.
543 static inline void htb_deactivate(struct htb_sched *q, struct htb_class *cl)
545 WARN_ON(!cl->prio_activity);
547 htb_deactivate_prios(q, cl);
548 cl->prio_activity = 0;
549 list_del_init(&cl->un.leaf.drop_list);
552 static int htb_enqueue(struct sk_buff *skb, struct Qdisc *sch)
554 int uninitialized_var(ret);
555 struct htb_sched *q = qdisc_priv(sch);
556 struct htb_class *cl = htb_classify(skb, sch, &ret);
558 if (cl == HTB_DIRECT) {
559 /* enqueue to helper queue */
560 if (q->direct_queue.qlen < q->direct_qlen) {
561 __skb_queue_tail(&q->direct_queue, skb);
566 return NET_XMIT_DROP;
568 #ifdef CONFIG_NET_CLS_ACT
570 if (ret & __NET_XMIT_BYPASS)
575 } else if ((ret = qdisc_enqueue(skb, cl->un.leaf.q)) != NET_XMIT_SUCCESS) {
576 if (net_xmit_drop_count(ret)) {
582 cl->bstats.packets +=
583 skb_is_gso(skb)?skb_shinfo(skb)->gso_segs:1;
584 cl->bstats.bytes += qdisc_pkt_len(skb);
589 sch->bstats.packets += skb_is_gso(skb)?skb_shinfo(skb)->gso_segs:1;
590 sch->bstats.bytes += qdisc_pkt_len(skb);
591 return NET_XMIT_SUCCESS;
595 * htb_charge_class - charges amount "bytes" to leaf and ancestors
597 * Routine assumes that packet "bytes" long was dequeued from leaf cl
598 * borrowing from "level". It accounts bytes to ceil leaky bucket for
599 * leaf and all ancestors and to rate bucket for ancestors at levels
600 * "level" and higher. It also handles possible change of mode resulting
601 * from the update. Note that mode can also increase here (MAY_BORROW to
602 * CAN_SEND) because we can use more precise clock that event queue here.
603 * In such case we remove class from event queue first.
605 static void htb_charge_class(struct htb_sched *q, struct htb_class *cl,
606 int level, struct sk_buff *skb)
608 int bytes = qdisc_pkt_len(skb);
610 enum htb_cmode old_mode;
612 #define HTB_ACCNT(T,B,R) toks = diff + cl->T; \
613 if (toks > cl->B) toks = cl->B; \
614 toks -= L2T(cl, cl->R, bytes); \
615 if (toks <= -cl->mbuffer) toks = 1-cl->mbuffer; \
619 diff = psched_tdiff_bounded(q->now, cl->t_c, cl->mbuffer);
620 if (cl->level >= level) {
621 if (cl->level == level)
623 HTB_ACCNT(tokens, buffer, rate);
625 cl->xstats.borrows++;
626 cl->tokens += diff; /* we moved t_c; update tokens */
628 HTB_ACCNT(ctokens, cbuffer, ceil);
631 old_mode = cl->cmode;
633 htb_change_class_mode(q, cl, &diff);
634 if (old_mode != cl->cmode) {
635 if (old_mode != HTB_CAN_SEND)
636 htb_safe_rb_erase(&cl->pq_node, q->wait_pq + cl->level);
637 if (cl->cmode != HTB_CAN_SEND)
638 htb_add_to_wait_tree(q, cl, diff);
641 /* update byte stats except for leaves which are already updated */
643 cl->bstats.bytes += bytes;
644 cl->bstats.packets += skb_is_gso(skb)?
645 skb_shinfo(skb)->gso_segs:1;
652 * htb_do_events - make mode changes to classes at the level
654 * Scans event queue for pending events and applies them. Returns time of
655 * next pending event (0 for no event in pq).
656 * Note: Applied are events whose have cl->pq_key <= q->now.
658 static psched_time_t htb_do_events(struct htb_sched *q, int level)
660 /* don't run for longer than 2 jiffies; 2 is used instead of
661 1 to simplify things when jiffy is going to be incremented
663 unsigned long stop_at = jiffies + 2;
664 while (time_before(jiffies, stop_at)) {
665 struct htb_class *cl;
667 struct rb_node *p = rb_first(&q->wait_pq[level]);
672 cl = rb_entry(p, struct htb_class, pq_node);
673 if (cl->pq_key > q->now)
676 htb_safe_rb_erase(p, q->wait_pq + level);
677 diff = psched_tdiff_bounded(q->now, cl->t_c, cl->mbuffer);
678 htb_change_class_mode(q, cl, &diff);
679 if (cl->cmode != HTB_CAN_SEND)
680 htb_add_to_wait_tree(q, cl, diff);
682 /* too much load - let's continue on next jiffie */
683 return q->now + PSCHED_TICKS_PER_SEC / HZ;
686 /* Returns class->node+prio from id-tree where classe's id is >= id. NULL
687 is no such one exists. */
688 static struct rb_node *htb_id_find_next_upper(int prio, struct rb_node *n,
691 struct rb_node *r = NULL;
693 struct htb_class *cl =
694 rb_entry(n, struct htb_class, node[prio]);
695 if (id == cl->common.classid)
698 if (id > cl->common.classid) {
709 * htb_lookup_leaf - returns next leaf class in DRR order
711 * Find leaf where current feed pointers points to.
713 static struct htb_class *htb_lookup_leaf(struct rb_root *tree, int prio,
714 struct rb_node **pptr, u32 * pid)
718 struct rb_node *root;
719 struct rb_node **pptr;
721 } stk[TC_HTB_MAXDEPTH], *sp = stk;
723 WARN_ON(!tree->rb_node);
724 sp->root = tree->rb_node;
728 for (i = 0; i < 65535; i++) {
729 if (!*sp->pptr && *sp->pid) {
730 /* ptr was invalidated but id is valid - try to recover
731 the original or next ptr */
733 htb_id_find_next_upper(prio, sp->root, *sp->pid);
735 *sp->pid = 0; /* ptr is valid now so that remove this hint as it
736 can become out of date quickly */
737 if (!*sp->pptr) { /* we are at right end; rewind & go up */
738 *sp->pptr = sp->root;
739 while ((*sp->pptr)->rb_left)
740 *sp->pptr = (*sp->pptr)->rb_left;
746 htb_next_rb_node(sp->pptr);
749 struct htb_class *cl;
750 cl = rb_entry(*sp->pptr, struct htb_class, node[prio]);
753 (++sp)->root = cl->un.inner.feed[prio].rb_node;
754 sp->pptr = cl->un.inner.ptr + prio;
755 sp->pid = cl->un.inner.last_ptr_id + prio;
762 /* dequeues packet at given priority and level; call only if
763 you are sure that there is active class at prio/level */
764 static struct sk_buff *htb_dequeue_tree(struct htb_sched *q, int prio,
767 struct sk_buff *skb = NULL;
768 struct htb_class *cl, *start;
769 /* look initial class up in the row */
770 start = cl = htb_lookup_leaf(q->row[level] + prio, prio,
771 q->ptr[level] + prio,
772 q->last_ptr_id[level] + prio);
780 /* class can be empty - it is unlikely but can be true if leaf
781 qdisc drops packets in enqueue routine or if someone used
782 graft operation on the leaf since last dequeue;
783 simply deactivate and skip such class */
784 if (unlikely(cl->un.leaf.q->q.qlen == 0)) {
785 struct htb_class *next;
786 htb_deactivate(q, cl);
788 /* row/level might become empty */
789 if ((q->row_mask[level] & (1 << prio)) == 0)
792 next = htb_lookup_leaf(q->row[level] + prio,
793 prio, q->ptr[level] + prio,
794 q->last_ptr_id[level] + prio);
796 if (cl == start) /* fix start if we just deleted it */
802 skb = cl->un.leaf.q->dequeue(cl->un.leaf.q);
803 if (likely(skb != NULL))
807 "htb: class %X isn't work conserving ?!\n",
812 htb_next_rb_node((level ? cl->parent->un.inner.ptr : q->
814 cl = htb_lookup_leaf(q->row[level] + prio, prio,
815 q->ptr[level] + prio,
816 q->last_ptr_id[level] + prio);
818 } while (cl != start);
820 if (likely(skb != NULL)) {
821 cl->un.leaf.deficit[level] -= qdisc_pkt_len(skb);
822 if (cl->un.leaf.deficit[level] < 0) {
823 cl->un.leaf.deficit[level] += cl->un.leaf.quantum;
824 htb_next_rb_node((level ? cl->parent->un.inner.ptr : q->
827 /* this used to be after charge_class but this constelation
828 gives us slightly better performance */
829 if (!cl->un.leaf.q->q.qlen)
830 htb_deactivate(q, cl);
831 htb_charge_class(q, cl, level, skb);
836 static struct sk_buff *htb_dequeue(struct Qdisc *sch)
838 struct sk_buff *skb = NULL;
839 struct htb_sched *q = qdisc_priv(sch);
841 psched_time_t next_event;
843 /* try to dequeue direct packets as high prio (!) to minimize cpu work */
844 skb = __skb_dequeue(&q->direct_queue);
846 sch->flags &= ~TCQ_F_THROTTLED;
853 q->now = psched_get_time();
855 next_event = q->now + 5 * PSCHED_TICKS_PER_SEC;
857 for (level = 0; level < TC_HTB_MAXDEPTH; level++) {
858 /* common case optimization - skip event handler quickly */
862 if (q->now >= q->near_ev_cache[level]) {
863 event = htb_do_events(q, level);
865 event = q->now + PSCHED_TICKS_PER_SEC;
866 q->near_ev_cache[level] = event;
868 event = q->near_ev_cache[level];
870 if (event && next_event > event)
873 m = ~q->row_mask[level];
874 while (m != (int)(-1)) {
877 skb = htb_dequeue_tree(q, prio, level);
878 if (likely(skb != NULL)) {
880 sch->flags &= ~TCQ_F_THROTTLED;
885 sch->qstats.overlimits++;
886 qdisc_watchdog_schedule(&q->watchdog, next_event);
891 /* try to drop from each class (by prio) until one succeed */
892 static unsigned int htb_drop(struct Qdisc *sch)
894 struct htb_sched *q = qdisc_priv(sch);
897 for (prio = TC_HTB_NUMPRIO - 1; prio >= 0; prio--) {
899 list_for_each(p, q->drops + prio) {
900 struct htb_class *cl = list_entry(p, struct htb_class,
903 if (cl->un.leaf.q->ops->drop &&
904 (len = cl->un.leaf.q->ops->drop(cl->un.leaf.q))) {
906 if (!cl->un.leaf.q->q.qlen)
907 htb_deactivate(q, cl);
915 /* reset all classes */
916 /* always caled under BH & queue lock */
917 static void htb_reset(struct Qdisc *sch)
919 struct htb_sched *q = qdisc_priv(sch);
920 struct htb_class *cl;
921 struct hlist_node *n;
924 for (i = 0; i < q->clhash.hashsize; i++) {
925 hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode) {
927 memset(&cl->un.inner, 0, sizeof(cl->un.inner));
930 qdisc_reset(cl->un.leaf.q);
931 INIT_LIST_HEAD(&cl->un.leaf.drop_list);
933 cl->prio_activity = 0;
934 cl->cmode = HTB_CAN_SEND;
938 qdisc_watchdog_cancel(&q->watchdog);
939 __skb_queue_purge(&q->direct_queue);
941 memset(q->row, 0, sizeof(q->row));
942 memset(q->row_mask, 0, sizeof(q->row_mask));
943 memset(q->wait_pq, 0, sizeof(q->wait_pq));
944 memset(q->ptr, 0, sizeof(q->ptr));
945 for (i = 0; i < TC_HTB_NUMPRIO; i++)
946 INIT_LIST_HEAD(q->drops + i);
949 static const struct nla_policy htb_policy[TCA_HTB_MAX + 1] = {
950 [TCA_HTB_PARMS] = { .len = sizeof(struct tc_htb_opt) },
951 [TCA_HTB_INIT] = { .len = sizeof(struct tc_htb_glob) },
952 [TCA_HTB_CTAB] = { .type = NLA_BINARY, .len = TC_RTAB_SIZE },
953 [TCA_HTB_RTAB] = { .type = NLA_BINARY, .len = TC_RTAB_SIZE },
956 static int htb_init(struct Qdisc *sch, struct nlattr *opt)
958 struct htb_sched *q = qdisc_priv(sch);
959 struct nlattr *tb[TCA_HTB_INIT + 1];
960 struct tc_htb_glob *gopt;
967 err = nla_parse_nested(tb, TCA_HTB_INIT, opt, htb_policy);
971 if (tb[TCA_HTB_INIT] == NULL) {
972 printk(KERN_ERR "HTB: hey probably you have bad tc tool ?\n");
975 gopt = nla_data(tb[TCA_HTB_INIT]);
976 if (gopt->version != HTB_VER >> 16) {
978 "HTB: need tc/htb version %d (minor is %d), you have %d\n",
979 HTB_VER >> 16, HTB_VER & 0xffff, gopt->version);
983 err = qdisc_class_hash_init(&q->clhash);
986 for (i = 0; i < TC_HTB_NUMPRIO; i++)
987 INIT_LIST_HEAD(q->drops + i);
989 qdisc_watchdog_init(&q->watchdog, sch);
990 skb_queue_head_init(&q->direct_queue);
992 q->direct_qlen = qdisc_dev(sch)->tx_queue_len;
993 if (q->direct_qlen < 2) /* some devices have zero tx_queue_len */
996 if ((q->rate2quantum = gopt->rate2quantum) < 1)
998 q->defcls = gopt->defcls;
1003 static int htb_dump(struct Qdisc *sch, struct sk_buff *skb)
1005 spinlock_t *root_lock = qdisc_root_sleeping_lock(sch);
1006 struct htb_sched *q = qdisc_priv(sch);
1007 struct nlattr *nest;
1008 struct tc_htb_glob gopt;
1010 spin_lock_bh(root_lock);
1012 gopt.direct_pkts = q->direct_pkts;
1013 gopt.version = HTB_VER;
1014 gopt.rate2quantum = q->rate2quantum;
1015 gopt.defcls = q->defcls;
1018 nest = nla_nest_start(skb, TCA_OPTIONS);
1020 goto nla_put_failure;
1021 NLA_PUT(skb, TCA_HTB_INIT, sizeof(gopt), &gopt);
1022 nla_nest_end(skb, nest);
1024 spin_unlock_bh(root_lock);
1028 spin_unlock_bh(root_lock);
1029 nla_nest_cancel(skb, nest);
1033 static int htb_dump_class(struct Qdisc *sch, unsigned long arg,
1034 struct sk_buff *skb, struct tcmsg *tcm)
1036 struct htb_class *cl = (struct htb_class *)arg;
1037 spinlock_t *root_lock = qdisc_root_sleeping_lock(sch);
1038 struct nlattr *nest;
1039 struct tc_htb_opt opt;
1041 spin_lock_bh(root_lock);
1042 tcm->tcm_parent = cl->parent ? cl->parent->common.classid : TC_H_ROOT;
1043 tcm->tcm_handle = cl->common.classid;
1044 if (!cl->level && cl->un.leaf.q)
1045 tcm->tcm_info = cl->un.leaf.q->handle;
1047 nest = nla_nest_start(skb, TCA_OPTIONS);
1049 goto nla_put_failure;
1051 memset(&opt, 0, sizeof(opt));
1053 opt.rate = cl->rate->rate;
1054 opt.buffer = cl->buffer;
1055 opt.ceil = cl->ceil->rate;
1056 opt.cbuffer = cl->cbuffer;
1057 opt.quantum = cl->un.leaf.quantum;
1058 opt.prio = cl->un.leaf.prio;
1059 opt.level = cl->level;
1060 NLA_PUT(skb, TCA_HTB_PARMS, sizeof(opt), &opt);
1062 nla_nest_end(skb, nest);
1063 spin_unlock_bh(root_lock);
1067 spin_unlock_bh(root_lock);
1068 nla_nest_cancel(skb, nest);
1073 htb_dump_class_stats(struct Qdisc *sch, unsigned long arg, struct gnet_dump *d)
1075 struct htb_class *cl = (struct htb_class *)arg;
1077 if (!cl->level && cl->un.leaf.q)
1078 cl->qstats.qlen = cl->un.leaf.q->q.qlen;
1079 cl->xstats.tokens = cl->tokens;
1080 cl->xstats.ctokens = cl->ctokens;
1082 if (gnet_stats_copy_basic(d, &cl->bstats) < 0 ||
1083 gnet_stats_copy_rate_est(d, &cl->rate_est) < 0 ||
1084 gnet_stats_copy_queue(d, &cl->qstats) < 0)
1087 return gnet_stats_copy_app(d, &cl->xstats, sizeof(cl->xstats));
1090 static int htb_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
1093 struct htb_class *cl = (struct htb_class *)arg;
1095 if (cl && !cl->level) {
1097 (new = qdisc_create_dflt(qdisc_dev(sch), sch->dev_queue,
1099 cl->common.classid))
1103 if ((*old = xchg(&cl->un.leaf.q, new)) != NULL) {
1104 qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
1107 sch_tree_unlock(sch);
1113 static struct Qdisc *htb_leaf(struct Qdisc *sch, unsigned long arg)
1115 struct htb_class *cl = (struct htb_class *)arg;
1116 return (cl && !cl->level) ? cl->un.leaf.q : NULL;
1119 static void htb_qlen_notify(struct Qdisc *sch, unsigned long arg)
1121 struct htb_class *cl = (struct htb_class *)arg;
1123 if (cl->un.leaf.q->q.qlen == 0)
1124 htb_deactivate(qdisc_priv(sch), cl);
1127 static unsigned long htb_get(struct Qdisc *sch, u32 classid)
1129 struct htb_class *cl = htb_find(classid, sch);
1132 return (unsigned long)cl;
1135 static inline int htb_parent_last_child(struct htb_class *cl)
1138 /* the root class */
1140 if (cl->parent->children > 1)
1141 /* not the last child */
1146 static void htb_parent_to_leaf(struct htb_sched *q, struct htb_class *cl,
1147 struct Qdisc *new_q)
1149 struct htb_class *parent = cl->parent;
1151 WARN_ON(cl->level || !cl->un.leaf.q || cl->prio_activity);
1153 if (parent->cmode != HTB_CAN_SEND)
1154 htb_safe_rb_erase(&parent->pq_node, q->wait_pq + parent->level);
1157 memset(&parent->un.inner, 0, sizeof(parent->un.inner));
1158 INIT_LIST_HEAD(&parent->un.leaf.drop_list);
1159 parent->un.leaf.q = new_q ? new_q : &noop_qdisc;
1160 parent->un.leaf.quantum = parent->quantum;
1161 parent->un.leaf.prio = parent->prio;
1162 parent->tokens = parent->buffer;
1163 parent->ctokens = parent->cbuffer;
1164 parent->t_c = psched_get_time();
1165 parent->cmode = HTB_CAN_SEND;
1168 static void htb_destroy_class(struct Qdisc *sch, struct htb_class *cl)
1171 WARN_ON(!cl->un.leaf.q);
1172 qdisc_destroy(cl->un.leaf.q);
1174 gen_kill_estimator(&cl->bstats, &cl->rate_est);
1175 qdisc_put_rtab(cl->rate);
1176 qdisc_put_rtab(cl->ceil);
1178 tcf_destroy_chain(&cl->filter_list);
1182 /* always caled under BH & queue lock */
1183 static void htb_destroy(struct Qdisc *sch)
1185 struct htb_sched *q = qdisc_priv(sch);
1186 struct hlist_node *n, *next;
1187 struct htb_class *cl;
1190 qdisc_watchdog_cancel(&q->watchdog);
1191 /* This line used to be after htb_destroy_class call below
1192 and surprisingly it worked in 2.4. But it must precede it
1193 because filter need its target class alive to be able to call
1194 unbind_filter on it (without Oops). */
1195 tcf_destroy_chain(&q->filter_list);
1197 for (i = 0; i < q->clhash.hashsize; i++) {
1198 hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode)
1199 tcf_destroy_chain(&cl->filter_list);
1201 for (i = 0; i < q->clhash.hashsize; i++) {
1202 hlist_for_each_entry_safe(cl, n, next, &q->clhash.hash[i],
1204 htb_destroy_class(sch, cl);
1206 qdisc_class_hash_destroy(&q->clhash);
1207 __skb_queue_purge(&q->direct_queue);
1210 static int htb_delete(struct Qdisc *sch, unsigned long arg)
1212 struct htb_sched *q = qdisc_priv(sch);
1213 struct htb_class *cl = (struct htb_class *)arg;
1215 struct Qdisc *new_q = NULL;
1218 // TODO: why don't allow to delete subtree ? references ? does
1219 // tc subsys quarantee us that in htb_destroy it holds no class
1220 // refs so that we can remove children safely there ?
1221 if (cl->children || cl->filter_cnt)
1224 if (!cl->level && htb_parent_last_child(cl)) {
1225 new_q = qdisc_create_dflt(qdisc_dev(sch), sch->dev_queue,
1227 cl->parent->common.classid);
1234 qlen = cl->un.leaf.q->q.qlen;
1235 qdisc_reset(cl->un.leaf.q);
1236 qdisc_tree_decrease_qlen(cl->un.leaf.q, qlen);
1239 /* delete from hash and active; remainder in destroy_class */
1240 qdisc_class_hash_remove(&q->clhash, &cl->common);
1242 cl->parent->children--;
1244 if (cl->prio_activity)
1245 htb_deactivate(q, cl);
1247 if (cl->cmode != HTB_CAN_SEND)
1248 htb_safe_rb_erase(&cl->pq_node, q->wait_pq + cl->level);
1251 htb_parent_to_leaf(q, cl, new_q);
1253 if (--cl->refcnt == 0)
1254 htb_destroy_class(sch, cl);
1256 sch_tree_unlock(sch);
1260 static void htb_put(struct Qdisc *sch, unsigned long arg)
1262 struct htb_class *cl = (struct htb_class *)arg;
1264 if (--cl->refcnt == 0)
1265 htb_destroy_class(sch, cl);
1268 static int htb_change_class(struct Qdisc *sch, u32 classid,
1269 u32 parentid, struct nlattr **tca,
1273 struct htb_sched *q = qdisc_priv(sch);
1274 struct htb_class *cl = (struct htb_class *)*arg, *parent;
1275 struct nlattr *opt = tca[TCA_OPTIONS];
1276 struct qdisc_rate_table *rtab = NULL, *ctab = NULL;
1277 struct nlattr *tb[TCA_HTB_RTAB + 1];
1278 struct tc_htb_opt *hopt;
1280 /* extract all subattrs from opt attr */
1284 err = nla_parse_nested(tb, TCA_HTB_RTAB, opt, htb_policy);
1289 if (tb[TCA_HTB_PARMS] == NULL)
1292 parent = parentid == TC_H_ROOT ? NULL : htb_find(parentid, sch);
1294 hopt = nla_data(tb[TCA_HTB_PARMS]);
1296 rtab = qdisc_get_rtab(&hopt->rate, tb[TCA_HTB_RTAB]);
1297 ctab = qdisc_get_rtab(&hopt->ceil, tb[TCA_HTB_CTAB]);
1301 if (!cl) { /* new class */
1302 struct Qdisc *new_q;
1306 struct gnet_estimator opt;
1309 .nla_len = nla_attr_size(sizeof(est.opt)),
1310 .nla_type = TCA_RATE,
1313 /* 4s interval, 16s averaging constant */
1319 /* check for valid classid */
1320 if (!classid || TC_H_MAJ(classid ^ sch->handle)
1321 || htb_find(classid, sch))
1324 /* check maximal depth */
1325 if (parent && parent->parent && parent->parent->level < 2) {
1326 printk(KERN_ERR "htb: tree is too deep\n");
1330 if ((cl = kzalloc(sizeof(*cl), GFP_KERNEL)) == NULL)
1333 gen_new_estimator(&cl->bstats, &cl->rate_est,
1334 qdisc_root_sleeping_lock(sch),
1335 tca[TCA_RATE] ? : &est.nla);
1338 INIT_LIST_HEAD(&cl->un.leaf.drop_list);
1339 RB_CLEAR_NODE(&cl->pq_node);
1341 for (prio = 0; prio < TC_HTB_NUMPRIO; prio++)
1342 RB_CLEAR_NODE(&cl->node[prio]);
1344 /* create leaf qdisc early because it uses kmalloc(GFP_KERNEL)
1345 so that can't be used inside of sch_tree_lock
1346 -- thanks to Karlis Peisenieks */
1347 new_q = qdisc_create_dflt(qdisc_dev(sch), sch->dev_queue,
1348 &pfifo_qdisc_ops, classid);
1350 if (parent && !parent->level) {
1351 unsigned int qlen = parent->un.leaf.q->q.qlen;
1353 /* turn parent into inner node */
1354 qdisc_reset(parent->un.leaf.q);
1355 qdisc_tree_decrease_qlen(parent->un.leaf.q, qlen);
1356 qdisc_destroy(parent->un.leaf.q);
1357 if (parent->prio_activity)
1358 htb_deactivate(q, parent);
1360 /* remove from evt list because of level change */
1361 if (parent->cmode != HTB_CAN_SEND) {
1362 htb_safe_rb_erase(&parent->pq_node, q->wait_pq);
1363 parent->cmode = HTB_CAN_SEND;
1365 parent->level = (parent->parent ? parent->parent->level
1366 : TC_HTB_MAXDEPTH) - 1;
1367 memset(&parent->un.inner, 0, sizeof(parent->un.inner));
1369 /* leaf (we) needs elementary qdisc */
1370 cl->un.leaf.q = new_q ? new_q : &noop_qdisc;
1372 cl->common.classid = classid;
1373 cl->parent = parent;
1375 /* set class to be in HTB_CAN_SEND state */
1376 cl->tokens = hopt->buffer;
1377 cl->ctokens = hopt->cbuffer;
1378 cl->mbuffer = 60 * PSCHED_TICKS_PER_SEC; /* 1min */
1379 cl->t_c = psched_get_time();
1380 cl->cmode = HTB_CAN_SEND;
1382 /* attach to the hash list and parent's family */
1383 qdisc_class_hash_insert(&q->clhash, &cl->common);
1388 gen_replace_estimator(&cl->bstats, &cl->rate_est,
1389 qdisc_root_sleeping_lock(sch),
1394 /* it used to be a nasty bug here, we have to check that node
1395 is really leaf before changing cl->un.leaf ! */
1397 cl->un.leaf.quantum = rtab->rate.rate / q->rate2quantum;
1398 if (!hopt->quantum && cl->un.leaf.quantum < 1000) {
1400 "HTB: quantum of class %X is small. Consider r2q change.\n",
1401 cl->common.classid);
1402 cl->un.leaf.quantum = 1000;
1404 if (!hopt->quantum && cl->un.leaf.quantum > 200000) {
1406 "HTB: quantum of class %X is big. Consider r2q change.\n",
1407 cl->common.classid);
1408 cl->un.leaf.quantum = 200000;
1411 cl->un.leaf.quantum = hopt->quantum;
1412 if ((cl->un.leaf.prio = hopt->prio) >= TC_HTB_NUMPRIO)
1413 cl->un.leaf.prio = TC_HTB_NUMPRIO - 1;
1415 /* backup for htb_parent_to_leaf */
1416 cl->quantum = cl->un.leaf.quantum;
1417 cl->prio = cl->un.leaf.prio;
1420 cl->buffer = hopt->buffer;
1421 cl->cbuffer = hopt->cbuffer;
1423 qdisc_put_rtab(cl->rate);
1426 qdisc_put_rtab(cl->ceil);
1428 sch_tree_unlock(sch);
1430 qdisc_class_hash_grow(sch, &q->clhash);
1432 *arg = (unsigned long)cl;
1437 qdisc_put_rtab(rtab);
1439 qdisc_put_rtab(ctab);
1443 static struct tcf_proto **htb_find_tcf(struct Qdisc *sch, unsigned long arg)
1445 struct htb_sched *q = qdisc_priv(sch);
1446 struct htb_class *cl = (struct htb_class *)arg;
1447 struct tcf_proto **fl = cl ? &cl->filter_list : &q->filter_list;
1452 static unsigned long htb_bind_filter(struct Qdisc *sch, unsigned long parent,
1455 struct htb_class *cl = htb_find(classid, sch);
1457 /*if (cl && !cl->level) return 0;
1458 The line above used to be there to prevent attaching filters to
1459 leaves. But at least tc_index filter uses this just to get class
1460 for other reasons so that we have to allow for it.
1462 19.6.2002 As Werner explained it is ok - bind filter is just
1463 another way to "lock" the class - unlike "get" this lock can
1464 be broken by class during destroy IIUC.
1468 return (unsigned long)cl;
1471 static void htb_unbind_filter(struct Qdisc *sch, unsigned long arg)
1473 struct htb_class *cl = (struct htb_class *)arg;
1479 static void htb_walk(struct Qdisc *sch, struct qdisc_walker *arg)
1481 struct htb_sched *q = qdisc_priv(sch);
1482 struct htb_class *cl;
1483 struct hlist_node *n;
1489 for (i = 0; i < q->clhash.hashsize; i++) {
1490 hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode) {
1491 if (arg->count < arg->skip) {
1495 if (arg->fn(sch, (unsigned long)cl, arg) < 0) {
1504 static const struct Qdisc_class_ops htb_class_ops = {
1507 .qlen_notify = htb_qlen_notify,
1510 .change = htb_change_class,
1511 .delete = htb_delete,
1513 .tcf_chain = htb_find_tcf,
1514 .bind_tcf = htb_bind_filter,
1515 .unbind_tcf = htb_unbind_filter,
1516 .dump = htb_dump_class,
1517 .dump_stats = htb_dump_class_stats,
1520 static struct Qdisc_ops htb_qdisc_ops __read_mostly = {
1522 .cl_ops = &htb_class_ops,
1524 .priv_size = sizeof(struct htb_sched),
1525 .enqueue = htb_enqueue,
1526 .dequeue = htb_dequeue,
1527 .peek = qdisc_peek_dequeued,
1531 .destroy = htb_destroy,
1532 .change = NULL /* htb_change */,
1534 .owner = THIS_MODULE,
1537 static int __init htb_module_init(void)
1539 return register_qdisc(&htb_qdisc_ops);
1541 static void __exit htb_module_exit(void)
1543 unregister_qdisc(&htb_qdisc_ops);
1546 module_init(htb_module_init)
1547 module_exit(htb_module_exit)
1548 MODULE_LICENSE("GPL");