1/*
   2 * net/sched/sch_htb.c	Hierarchical token bucket, feed tree version
   3 *
   4 *		This program is free software; you can redistribute it and/or
   5 *		modify it under the terms of the GNU General Public License
   6 *		as published by the Free Software Foundation; either version
   7 *		2 of the License, or (at your option) any later version.
   8 *
   9 * Authors:	Martin Devera, <devik@cdi.cz>
  10 *
  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
  22 *		Wilfried Weissmann
  23 *			spotted bug in dequeue code and helped with fix
  24 *		Jiri Fojtasek
  25 *			fixed requeue routine
  26 *		and many others. thanks.
  27 */
  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 <linux/workqueue.h>
  39#include <linux/slab.h>
  40#include <net/netlink.h>
 
  41#include <net/pkt_sched.h>
  42
  43/* HTB algorithm.
  44    Author: devik@cdi.cz
  45    ========================================================================
  46    HTB is like TBF with multiple classes. It is also similar to CBQ because
  47    it allows to assign priority to each class in hierarchy.
  48    In fact it is another implementation of Floyd's formal sharing.
  49
  50    Levels:
  51    Each class is assigned level. Leaf has ALWAYS level 0 and root
  52    classes have level TC_HTB_MAXDEPTH-1. Interior nodes has level
  53    one less than their parent.
  54*/
  55
  56static int htb_hysteresis __read_mostly = 0; /* whether to use mode hysteresis for speedup */
  57#define HTB_VER 0x30011		/* major must be matched with number suplied by TC as version */
  58
  59#if HTB_VER >> 16 != TC_HTB_PROTOVER
  60#error "Mismatched sch_htb.c and pkt_sch.h"
  61#endif
  62
  63/* Module parameter and sysfs export */
  64module_param    (htb_hysteresis, int, 0640);
  65MODULE_PARM_DESC(htb_hysteresis, "Hysteresis mode, less CPU load, less accurate");
  66
 
 
 
 
  67/* used internaly to keep status of single class */
  68enum htb_cmode {
  69	HTB_CANT_SEND,		/* class can't send and can't borrow */
  70	HTB_MAY_BORROW,		/* class can't send but may borrow */
  71	HTB_CAN_SEND		/* class can send */
  72};
  73
  74/* interior & leaf nodes; props specific to leaves are marked L: */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  75struct htb_class {
  76	struct Qdisc_class_common common;
  77	/* general class parameters */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  78	struct gnet_stats_basic_packed bstats;
  79	struct gnet_stats_queue qstats;
  80	struct gnet_stats_rate_est rate_est;
  81	struct tc_htb_xstats xstats;	/* our special stats */
  82	int refcnt;		/* usage count of this class */
  83
  84	/* topology */
  85	int level;		/* our level (see above) */
  86	unsigned int children;
  87	struct htb_class *parent;	/* parent class */
  88
  89	int prio;		/* these two are used only by leaves... */
  90	int quantum;		/* but stored for parent-to-leaf return */
 
  91
  92	union {
  93		struct htb_class_leaf {
  94			struct Qdisc *q;
  95			int deficit[TC_HTB_MAXDEPTH];
  96			struct list_head drop_list;
 
 
  97		} leaf;
  98		struct htb_class_inner {
  99			struct rb_root feed[TC_HTB_NUMPRIO];	/* feed trees */
 100			struct rb_node *ptr[TC_HTB_NUMPRIO];	/* current class ptr */
 101			/* When class changes from state 1->2 and disconnects from
 102			 * parent's feed then we lost ptr value and start from the
 103			 * first child again. Here we store classid of the
 104			 * last valid ptr (used when ptr is NULL).
 105			 */
 106			u32 last_ptr_id[TC_HTB_NUMPRIO];
 107		} inner;
 108	} un;
 109	struct rb_node node[TC_HTB_NUMPRIO];	/* node for self or feed tree */
 110	struct rb_node pq_node;	/* node for event queue */
 111	psched_time_t pq_key;
 112
 113	int prio_activity;	/* for which prios are we active */
 114	enum htb_cmode cmode;	/* current mode of the class */
 115
 116	/* class attached filters */
 117	struct tcf_proto *filter_list;
 118	int filter_cnt;
 119
 120	/* token bucket parameters */
 121	struct qdisc_rate_table *rate;	/* rate table of the class itself */
 122	struct qdisc_rate_table *ceil;	/* ceiling rate (limits borrows too) */
 123	long buffer, cbuffer;	/* token bucket depth/rate */
 124	psched_tdiff_t mbuffer;	/* max wait time */
 125	long tokens, ctokens;	/* current number of tokens */
 126	psched_time_t t_c;	/* checkpoint time */
 
 
 
 
 127};
 128
 129struct htb_sched {
 130	struct Qdisc_class_hash clhash;
 131	struct list_head drops[TC_HTB_NUMPRIO];/* active leaves (for drops) */
 132
 133	/* self list - roots of self generating tree */
 134	struct rb_root row[TC_HTB_MAXDEPTH][TC_HTB_NUMPRIO];
 135	int row_mask[TC_HTB_MAXDEPTH];
 136	struct rb_node *ptr[TC_HTB_MAXDEPTH][TC_HTB_NUMPRIO];
 137	u32 last_ptr_id[TC_HTB_MAXDEPTH][TC_HTB_NUMPRIO];
 138
 139	/* self wait list - roots of wait PQs per row */
 140	struct rb_root wait_pq[TC_HTB_MAXDEPTH];
 141
 142	/* time of nearest event per level (row) */
 143	psched_time_t near_ev_cache[TC_HTB_MAXDEPTH];
 
 
 144
 145	int defcls;		/* class where unclassified flows go to */
 
 
 146
 147	/* filters for qdisc itself */
 148	struct tcf_proto *filter_list;
 149
 150	int rate2quantum;	/* quant = rate / rate2quantum */
 151	psched_time_t now;	/* cached dequeue time */
 152	struct qdisc_watchdog watchdog;
 153
 154	/* non shaped skbs; let them go directly thru */
 155	struct sk_buff_head direct_queue;
 156	int direct_qlen;	/* max qlen of above */
 157
 158	long direct_pkts;
 159
 160#define HTB_WARN_TOOMANYEVENTS	0x1
 161	unsigned int warned;	/* only one warning */
 162	struct work_struct work;
 163};
 164
 165/* find class in global hash table using given handle */
 166static inline struct htb_class *htb_find(u32 handle, struct Qdisc *sch)
 167{
 168	struct htb_sched *q = qdisc_priv(sch);
 169	struct Qdisc_class_common *clc;
 170
 171	clc = qdisc_class_find(&q->clhash, handle);
 172	if (clc == NULL)
 173		return NULL;
 174	return container_of(clc, struct htb_class, common);
 175}
 176
 177/**
 178 * htb_classify - classify a packet into class
 179 *
 180 * It returns NULL if the packet should be dropped or -1 if the packet
 181 * should be passed directly thru. In all other cases leaf class is returned.
 182 * We allow direct class selection by classid in priority. The we examine
 183 * filters in qdisc and in inner nodes (if higher filter points to the inner
 184 * node). If we end up with classid MAJOR:0 we enqueue the skb into special
 185 * internal fifo (direct). These packets then go directly thru. If we still
 186 * have no valid leaf we try to use MAJOR:default leaf. It still unsuccessful
 187 * then finish and return direct queue.
 188 */
 189#define HTB_DIRECT ((struct htb_class *)-1L)
 190
 191static struct htb_class *htb_classify(struct sk_buff *skb, struct Qdisc *sch,
 192				      int *qerr)
 193{
 194	struct htb_sched *q = qdisc_priv(sch);
 195	struct htb_class *cl;
 196	struct tcf_result res;
 197	struct tcf_proto *tcf;
 198	int result;
 199
 200	/* allow to select class by setting skb->priority to valid classid;
 201	 * note that nfmark can be used too by attaching filter fw with no
 202	 * rules in it
 203	 */
 204	if (skb->priority == sch->handle)
 205		return HTB_DIRECT;	/* X:0 (direct flow) selected */
 206	cl = htb_find(skb->priority, sch);
 207	if (cl && cl->level == 0)
 208		return cl;
 
 
 
 
 
 
 209
 210	*qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
 211	tcf = q->filter_list;
 212	while (tcf && (result = tc_classify(skb, tcf, &res)) >= 0) {
 213#ifdef CONFIG_NET_CLS_ACT
 214		switch (result) {
 215		case TC_ACT_QUEUED:
 216		case TC_ACT_STOLEN:
 217			*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
 218		case TC_ACT_SHOT:
 219			return NULL;
 220		}
 221#endif
 222		cl = (void *)res.class;
 223		if (!cl) {
 224			if (res.classid == sch->handle)
 225				return HTB_DIRECT;	/* X:0 (direct flow) */
 226			cl = htb_find(res.classid, sch);
 227			if (!cl)
 228				break;	/* filter selected invalid classid */
 229		}
 230		if (!cl->level)
 231			return cl;	/* we hit leaf; return it */
 232
 233		/* we have got inner class; apply inner filter chain */
 234		tcf = cl->filter_list;
 235	}
 236	/* classification failed; try to use default class */
 237	cl = htb_find(TC_H_MAKE(TC_H_MAJ(sch->handle), q->defcls), sch);
 238	if (!cl || cl->level)
 239		return HTB_DIRECT;	/* bad default .. this is safe bet */
 240	return cl;
 241}
 242
 243/**
 244 * htb_add_to_id_tree - adds class to the round robin list
 245 *
 246 * Routine adds class to the list (actually tree) sorted by classid.
 247 * Make sure that class is not already on such list for given prio.
 248 */
 249static void htb_add_to_id_tree(struct rb_root *root,
 250			       struct htb_class *cl, int prio)
 251{
 252	struct rb_node **p = &root->rb_node, *parent = NULL;
 253
 254	while (*p) {
 255		struct htb_class *c;
 256		parent = *p;
 257		c = rb_entry(parent, struct htb_class, node[prio]);
 258
 259		if (cl->common.classid > c->common.classid)
 260			p = &parent->rb_right;
 261		else
 262			p = &parent->rb_left;
 263	}
 264	rb_link_node(&cl->node[prio], parent, p);
 265	rb_insert_color(&cl->node[prio], root);
 266}
 267
 268/**
 269 * htb_add_to_wait_tree - adds class to the event queue with delay
 270 *
 271 * The class is added to priority event queue to indicate that class will
 272 * change its mode in cl->pq_key microseconds. Make sure that class is not
 273 * already in the queue.
 274 */
 275static void htb_add_to_wait_tree(struct htb_sched *q,
 276				 struct htb_class *cl, long delay)
 277{
 278	struct rb_node **p = &q->wait_pq[cl->level].rb_node, *parent = NULL;
 279
 280	cl->pq_key = q->now + delay;
 281	if (cl->pq_key == q->now)
 282		cl->pq_key++;
 283
 284	/* update the nearest event cache */
 285	if (q->near_ev_cache[cl->level] > cl->pq_key)
 286		q->near_ev_cache[cl->level] = cl->pq_key;
 287
 288	while (*p) {
 289		struct htb_class *c;
 290		parent = *p;
 291		c = rb_entry(parent, struct htb_class, pq_node);
 292		if (cl->pq_key >= c->pq_key)
 293			p = &parent->rb_right;
 294		else
 295			p = &parent->rb_left;
 296	}
 297	rb_link_node(&cl->pq_node, parent, p);
 298	rb_insert_color(&cl->pq_node, &q->wait_pq[cl->level]);
 299}
 300
 301/**
 302 * htb_next_rb_node - finds next node in binary tree
 303 *
 304 * When we are past last key we return NULL.
 305 * Average complexity is 2 steps per call.
 306 */
 307static inline void htb_next_rb_node(struct rb_node **n)
 308{
 309	*n = rb_next(*n);
 310}
 311
 312/**
 313 * htb_add_class_to_row - add class to its row
 314 *
 315 * The class is added to row at priorities marked in mask.
 316 * It does nothing if mask == 0.
 317 */
 318static inline void htb_add_class_to_row(struct htb_sched *q,
 319					struct htb_class *cl, int mask)
 320{
 321	q->row_mask[cl->level] |= mask;
 322	while (mask) {
 323		int prio = ffz(~mask);
 324		mask &= ~(1 << prio);
 325		htb_add_to_id_tree(q->row[cl->level] + prio, cl, prio);
 326	}
 327}
 328
 329/* If this triggers, it is a bug in this code, but it need not be fatal */
 330static void htb_safe_rb_erase(struct rb_node *rb, struct rb_root *root)
 331{
 332	if (RB_EMPTY_NODE(rb)) {
 333		WARN_ON(1);
 334	} else {
 335		rb_erase(rb, root);
 336		RB_CLEAR_NODE(rb);
 337	}
 338}
 339
 340
 341/**
 342 * htb_remove_class_from_row - removes class from its row
 343 *
 344 * The class is removed from row at priorities marked in mask.
 345 * It does nothing if mask == 0.
 346 */
 347static inline void htb_remove_class_from_row(struct htb_sched *q,
 348						 struct htb_class *cl, int mask)
 349{
 350	int m = 0;
 
 351
 352	while (mask) {
 353		int prio = ffz(~mask);
 
 354
 355		mask &= ~(1 << prio);
 356		if (q->ptr[cl->level][prio] == cl->node + prio)
 357			htb_next_rb_node(q->ptr[cl->level] + prio);
 358
 359		htb_safe_rb_erase(cl->node + prio, q->row[cl->level] + prio);
 360		if (!q->row[cl->level][prio].rb_node)
 361			m |= 1 << prio;
 362	}
 363	q->row_mask[cl->level] &= ~m;
 364}
 365
 366/**
 367 * htb_activate_prios - creates active classe's feed chain
 368 *
 369 * The class is connected to ancestors and/or appropriate rows
 370 * for priorities it is participating on. cl->cmode must be new
 371 * (activated) mode. It does nothing if cl->prio_activity == 0.
 372 */
 373static void htb_activate_prios(struct htb_sched *q, struct htb_class *cl)
 374{
 375	struct htb_class *p = cl->parent;
 376	long m, mask = cl->prio_activity;
 377
 378	while (cl->cmode == HTB_MAY_BORROW && p && mask) {
 379		m = mask;
 380		while (m) {
 381			int prio = ffz(~m);
 382			m &= ~(1 << prio);
 383
 384			if (p->un.inner.feed[prio].rb_node)
 385				/* parent already has its feed in use so that
 386				 * reset bit in mask as parent is already ok
 387				 */
 388				mask &= ~(1 << prio);
 389
 390			htb_add_to_id_tree(p->un.inner.feed + prio, cl, prio);
 391		}
 392		p->prio_activity |= mask;
 393		cl = p;
 394		p = cl->parent;
 395
 396	}
 397	if (cl->cmode == HTB_CAN_SEND && mask)
 398		htb_add_class_to_row(q, cl, mask);
 399}
 400
 401/**
 402 * htb_deactivate_prios - remove class from feed chain
 403 *
 404 * cl->cmode must represent old mode (before deactivation). It does
 405 * nothing if cl->prio_activity == 0. Class is removed from all feed
 406 * chains and rows.
 407 */
 408static void htb_deactivate_prios(struct htb_sched *q, struct htb_class *cl)
 409{
 410	struct htb_class *p = cl->parent;
 411	long m, mask = cl->prio_activity;
 412
 413	while (cl->cmode == HTB_MAY_BORROW && p && mask) {
 414		m = mask;
 415		mask = 0;
 416		while (m) {
 417			int prio = ffz(~m);
 418			m &= ~(1 << prio);
 419
 420			if (p->un.inner.ptr[prio] == cl->node + prio) {
 421				/* we are removing child which is pointed to from
 422				 * parent feed - forget the pointer but remember
 423				 * classid
 424				 */
 425				p->un.inner.last_ptr_id[prio] = cl->common.classid;
 426				p->un.inner.ptr[prio] = NULL;
 427			}
 428
 429			htb_safe_rb_erase(cl->node + prio, p->un.inner.feed + prio);
 
 430
 431			if (!p->un.inner.feed[prio].rb_node)
 432				mask |= 1 << prio;
 433		}
 434
 435		p->prio_activity &= ~mask;
 436		cl = p;
 437		p = cl->parent;
 438
 439	}
 440	if (cl->cmode == HTB_CAN_SEND && mask)
 441		htb_remove_class_from_row(q, cl, mask);
 442}
 443
 444static inline long htb_lowater(const struct htb_class *cl)
 445{
 446	if (htb_hysteresis)
 447		return cl->cmode != HTB_CANT_SEND ? -cl->cbuffer : 0;
 448	else
 449		return 0;
 450}
 451static inline long htb_hiwater(const struct htb_class *cl)
 452{
 453	if (htb_hysteresis)
 454		return cl->cmode == HTB_CAN_SEND ? -cl->buffer : 0;
 455	else
 456		return 0;
 457}
 458
 459
 460/**
 461 * htb_class_mode - computes and returns current class mode
 462 *
 463 * It computes cl's mode at time cl->t_c+diff and returns it. If mode
 464 * is not HTB_CAN_SEND then cl->pq_key is updated to time difference
 465 * from now to time when cl will change its state.
 466 * Also it is worth to note that class mode doesn't change simply
 467 * at cl->{c,}tokens == 0 but there can rather be hysteresis of
 468 * 0 .. -cl->{c,}buffer range. It is meant to limit number of
 469 * mode transitions per time unit. The speed gain is about 1/6.
 470 */
 471static inline enum htb_cmode
 472htb_class_mode(struct htb_class *cl, long *diff)
 473{
 474	long toks;
 475
 476	if ((toks = (cl->ctokens + *diff)) < htb_lowater(cl)) {
 477		*diff = -toks;
 478		return HTB_CANT_SEND;
 479	}
 480
 481	if ((toks = (cl->tokens + *diff)) >= htb_hiwater(cl))
 482		return HTB_CAN_SEND;
 483
 484	*diff = -toks;
 485	return HTB_MAY_BORROW;
 486}
 487
 488/**
 489 * htb_change_class_mode - changes classe's mode
 490 *
 491 * This should be the only way how to change classe's mode under normal
 492 * cirsumstances. Routine will update feed lists linkage, change mode
 493 * and add class to the wait event queue if appropriate. New mode should
 494 * be different from old one and cl->pq_key has to be valid if changing
 495 * to mode other than HTB_CAN_SEND (see htb_add_to_wait_tree).
 496 */
 497static void
 498htb_change_class_mode(struct htb_sched *q, struct htb_class *cl, long *diff)
 499{
 500	enum htb_cmode new_mode = htb_class_mode(cl, diff);
 501
 502	if (new_mode == cl->cmode)
 503		return;
 504
 505	if (cl->prio_activity) {	/* not necessary: speed optimization */
 506		if (cl->cmode != HTB_CANT_SEND)
 507			htb_deactivate_prios(q, cl);
 508		cl->cmode = new_mode;
 509		if (new_mode != HTB_CANT_SEND)
 510			htb_activate_prios(q, cl);
 511	} else
 512		cl->cmode = new_mode;
 513}
 514
 515/**
 516 * htb_activate - inserts leaf cl into appropriate active feeds
 517 *
 518 * Routine learns (new) priority of leaf and activates feed chain
 519 * for the prio. It can be called on already active leaf safely.
 520 * It also adds leaf into droplist.
 521 */
 522static inline void htb_activate(struct htb_sched *q, struct htb_class *cl)
 523{
 524	WARN_ON(cl->level || !cl->un.leaf.q || !cl->un.leaf.q->q.qlen);
 525
 526	if (!cl->prio_activity) {
 527		cl->prio_activity = 1 << cl->prio;
 528		htb_activate_prios(q, cl);
 529		list_add_tail(&cl->un.leaf.drop_list,
 530			      q->drops + cl->prio);
 531	}
 532}
 533
 534/**
 535 * htb_deactivate - remove leaf cl from active feeds
 536 *
 537 * Make sure that leaf is active. In the other words it can't be called
 538 * with non-active leaf. It also removes class from the drop list.
 539 */
 540static inline void htb_deactivate(struct htb_sched *q, struct htb_class *cl)
 541{
 542	WARN_ON(!cl->prio_activity);
 543
 544	htb_deactivate_prios(q, cl);
 545	cl->prio_activity = 0;
 546	list_del_init(&cl->un.leaf.drop_list);
 547}
 548
 549static int htb_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 550{
 551	int uninitialized_var(ret);
 552	struct htb_sched *q = qdisc_priv(sch);
 553	struct htb_class *cl = htb_classify(skb, sch, &ret);
 554
 555	if (cl == HTB_DIRECT) {
 556		/* enqueue to helper queue */
 557		if (q->direct_queue.qlen < q->direct_qlen) {
 558			__skb_queue_tail(&q->direct_queue, skb);
 559			q->direct_pkts++;
 560		} else {
 561			return qdisc_drop(skb, sch);
 562		}
 563#ifdef CONFIG_NET_CLS_ACT
 564	} else if (!cl) {
 565		if (ret & __NET_XMIT_BYPASS)
 566			sch->qstats.drops++;
 567		kfree_skb(skb);
 568		return ret;
 569#endif
 570	} else if ((ret = qdisc_enqueue(skb, cl->un.leaf.q)) != NET_XMIT_SUCCESS) {
 
 571		if (net_xmit_drop_count(ret)) {
 572			sch->qstats.drops++;
 573			cl->qstats.drops++;
 574		}
 575		return ret;
 576	} else {
 577		htb_activate(q, cl);
 578	}
 579
 
 580	sch->q.qlen++;
 581	return NET_XMIT_SUCCESS;
 582}
 583
 584static inline void htb_accnt_tokens(struct htb_class *cl, int bytes, long diff)
 585{
 586	long toks = diff + cl->tokens;
 587
 588	if (toks > cl->buffer)
 589		toks = cl->buffer;
 590	toks -= (long) qdisc_l2t(cl->rate, bytes);
 591	if (toks <= -cl->mbuffer)
 592		toks = 1 - cl->mbuffer;
 593
 594	cl->tokens = toks;
 595}
 596
 597static inline void htb_accnt_ctokens(struct htb_class *cl, int bytes, long diff)
 598{
 599	long toks = diff + cl->ctokens;
 600
 601	if (toks > cl->cbuffer)
 602		toks = cl->cbuffer;
 603	toks -= (long) qdisc_l2t(cl->ceil, bytes);
 604	if (toks <= -cl->mbuffer)
 605		toks = 1 - cl->mbuffer;
 606
 607	cl->ctokens = toks;
 608}
 609
 610/**
 611 * htb_charge_class - charges amount "bytes" to leaf and ancestors
 612 *
 613 * Routine assumes that packet "bytes" long was dequeued from leaf cl
 614 * borrowing from "level". It accounts bytes to ceil leaky bucket for
 615 * leaf and all ancestors and to rate bucket for ancestors at levels
 616 * "level" and higher. It also handles possible change of mode resulting
 617 * from the update. Note that mode can also increase here (MAY_BORROW to
 618 * CAN_SEND) because we can use more precise clock that event queue here.
 619 * In such case we remove class from event queue first.
 620 */
 621static void htb_charge_class(struct htb_sched *q, struct htb_class *cl,
 622			     int level, struct sk_buff *skb)
 623{
 624	int bytes = qdisc_pkt_len(skb);
 625	enum htb_cmode old_mode;
 626	long diff;
 627
 628	while (cl) {
 629		diff = psched_tdiff_bounded(q->now, cl->t_c, cl->mbuffer);
 630		if (cl->level >= level) {
 631			if (cl->level == level)
 632				cl->xstats.lends++;
 633			htb_accnt_tokens(cl, bytes, diff);
 634		} else {
 635			cl->xstats.borrows++;
 636			cl->tokens += diff;	/* we moved t_c; update tokens */
 637		}
 638		htb_accnt_ctokens(cl, bytes, diff);
 639		cl->t_c = q->now;
 640
 641		old_mode = cl->cmode;
 642		diff = 0;
 643		htb_change_class_mode(q, cl, &diff);
 644		if (old_mode != cl->cmode) {
 645			if (old_mode != HTB_CAN_SEND)
 646				htb_safe_rb_erase(&cl->pq_node, q->wait_pq + cl->level);
 647			if (cl->cmode != HTB_CAN_SEND)
 648				htb_add_to_wait_tree(q, cl, diff);
 649		}
 650
 651		/* update basic stats except for leaves which are already updated */
 652		if (cl->level)
 653			bstats_update(&cl->bstats, skb);
 654
 655		cl = cl->parent;
 656	}
 657}
 658
 659/**
 660 * htb_do_events - make mode changes to classes at the level
 661 *
 662 * Scans event queue for pending events and applies them. Returns time of
 663 * next pending event (0 for no event in pq, q->now for too many events).
 664 * Note: Applied are events whose have cl->pq_key <= q->now.
 665 */
 666static psched_time_t htb_do_events(struct htb_sched *q, int level,
 667				   unsigned long start)
 668{
 669	/* don't run for longer than 2 jiffies; 2 is used instead of
 670	 * 1 to simplify things when jiffy is going to be incremented
 671	 * too soon
 672	 */
 673	unsigned long stop_at = start + 2;
 
 
 674	while (time_before(jiffies, stop_at)) {
 675		struct htb_class *cl;
 676		long diff;
 677		struct rb_node *p = rb_first(&q->wait_pq[level]);
 678
 679		if (!p)
 680			return 0;
 681
 682		cl = rb_entry(p, struct htb_class, pq_node);
 683		if (cl->pq_key > q->now)
 684			return cl->pq_key;
 685
 686		htb_safe_rb_erase(p, q->wait_pq + level);
 687		diff = psched_tdiff_bounded(q->now, cl->t_c, cl->mbuffer);
 688		htb_change_class_mode(q, cl, &diff);
 689		if (cl->cmode != HTB_CAN_SEND)
 690			htb_add_to_wait_tree(q, cl, diff);
 691	}
 692
 693	/* too much load - let's continue after a break for scheduling */
 694	if (!(q->warned & HTB_WARN_TOOMANYEVENTS)) {
 695		pr_warning("htb: too many events!\n");
 696		q->warned |= HTB_WARN_TOOMANYEVENTS;
 697	}
 698
 699	return q->now;
 700}
 701
 702/* Returns class->node+prio from id-tree where classe's id is >= id. NULL
 703 * is no such one exists.
 704 */
 705static struct rb_node *htb_id_find_next_upper(int prio, struct rb_node *n,
 706					      u32 id)
 707{
 708	struct rb_node *r = NULL;
 709	while (n) {
 710		struct htb_class *cl =
 711		    rb_entry(n, struct htb_class, node[prio]);
 712
 713		if (id > cl->common.classid) {
 714			n = n->rb_right;
 715		} else if (id < cl->common.classid) {
 716			r = n;
 717			n = n->rb_left;
 718		} else {
 719			return n;
 720		}
 721	}
 722	return r;
 723}
 724
 725/**
 726 * htb_lookup_leaf - returns next leaf class in DRR order
 727 *
 728 * Find leaf where current feed pointers points to.
 729 */
 730static struct htb_class *htb_lookup_leaf(struct rb_root *tree, int prio,
 731					 struct rb_node **pptr, u32 * pid)
 732{
 733	int i;
 734	struct {
 735		struct rb_node *root;
 736		struct rb_node **pptr;
 737		u32 *pid;
 738	} stk[TC_HTB_MAXDEPTH], *sp = stk;
 739
 740	BUG_ON(!tree->rb_node);
 741	sp->root = tree->rb_node;
 742	sp->pptr = pptr;
 743	sp->pid = pid;
 744
 745	for (i = 0; i < 65535; i++) {
 746		if (!*sp->pptr && *sp->pid) {
 747			/* ptr was invalidated but id is valid - try to recover
 748			 * the original or next ptr
 749			 */
 750			*sp->pptr =
 751			    htb_id_find_next_upper(prio, sp->root, *sp->pid);
 752		}
 753		*sp->pid = 0;	/* ptr is valid now so that remove this hint as it
 754				 * can become out of date quickly
 755				 */
 756		if (!*sp->pptr) {	/* we are at right end; rewind & go up */
 757			*sp->pptr = sp->root;
 758			while ((*sp->pptr)->rb_left)
 759				*sp->pptr = (*sp->pptr)->rb_left;
 760			if (sp > stk) {
 761				sp--;
 762				if (!*sp->pptr) {
 763					WARN_ON(1);
 764					return NULL;
 765				}
 766				htb_next_rb_node(sp->pptr);
 767			}
 768		} else {
 769			struct htb_class *cl;
 
 
 770			cl = rb_entry(*sp->pptr, struct htb_class, node[prio]);
 771			if (!cl->level)
 772				return cl;
 773			(++sp)->root = cl->un.inner.feed[prio].rb_node;
 774			sp->pptr = cl->un.inner.ptr + prio;
 775			sp->pid = cl->un.inner.last_ptr_id + prio;
 
 776		}
 777	}
 778	WARN_ON(1);
 779	return NULL;
 780}
 781
 782/* dequeues packet at given priority and level; call only if
 783 * you are sure that there is active class at prio/level
 784 */
 785static struct sk_buff *htb_dequeue_tree(struct htb_sched *q, int prio,
 786					int level)
 787{
 788	struct sk_buff *skb = NULL;
 789	struct htb_class *cl, *start;
 
 
 
 790	/* look initial class up in the row */
 791	start = cl = htb_lookup_leaf(q->row[level] + prio, prio,
 792				     q->ptr[level] + prio,
 793				     q->last_ptr_id[level] + prio);
 794
 795	do {
 796next:
 797		if (unlikely(!cl))
 798			return NULL;
 799
 800		/* class can be empty - it is unlikely but can be true if leaf
 801		 * qdisc drops packets in enqueue routine or if someone used
 802		 * graft operation on the leaf since last dequeue;
 803		 * simply deactivate and skip such class
 804		 */
 805		if (unlikely(cl->un.leaf.q->q.qlen == 0)) {
 806			struct htb_class *next;
 807			htb_deactivate(q, cl);
 808
 809			/* row/level might become empty */
 810			if ((q->row_mask[level] & (1 << prio)) == 0)
 811				return NULL;
 812
 813			next = htb_lookup_leaf(q->row[level] + prio,
 814					       prio, q->ptr[level] + prio,
 815					       q->last_ptr_id[level] + prio);
 816
 817			if (cl == start)	/* fix start if we just deleted it */
 818				start = next;
 819			cl = next;
 820			goto next;
 821		}
 822
 823		skb = cl->un.leaf.q->dequeue(cl->un.leaf.q);
 824		if (likely(skb != NULL))
 825			break;
 826
 827		qdisc_warn_nonwc("htb", cl->un.leaf.q);
 828		htb_next_rb_node((level ? cl->parent->un.inner.ptr : q->
 829				  ptr[0]) + prio);
 830		cl = htb_lookup_leaf(q->row[level] + prio, prio,
 831				     q->ptr[level] + prio,
 832				     q->last_ptr_id[level] + prio);
 833
 834	} while (cl != start);
 835
 836	if (likely(skb != NULL)) {
 837		bstats_update(&cl->bstats, skb);
 838		cl->un.leaf.deficit[level] -= qdisc_pkt_len(skb);
 839		if (cl->un.leaf.deficit[level] < 0) {
 840			cl->un.leaf.deficit[level] += cl->quantum;
 841			htb_next_rb_node((level ? cl->parent->un.inner.ptr : q->
 842					  ptr[0]) + prio);
 843		}
 844		/* this used to be after charge_class but this constelation
 845		 * gives us slightly better performance
 846		 */
 847		if (!cl->un.leaf.q->q.qlen)
 848			htb_deactivate(q, cl);
 849		htb_charge_class(q, cl, level, skb);
 850	}
 851	return skb;
 852}
 853
 854static struct sk_buff *htb_dequeue(struct Qdisc *sch)
 855{
 856	struct sk_buff *skb;
 857	struct htb_sched *q = qdisc_priv(sch);
 858	int level;
 859	psched_time_t next_event;
 860	unsigned long start_at;
 861
 862	/* try to dequeue direct packets as high prio (!) to minimize cpu work */
 863	skb = __skb_dequeue(&q->direct_queue);
 864	if (skb != NULL) {
 865ok:
 866		qdisc_bstats_update(sch, skb);
 867		qdisc_unthrottled(sch);
 868		sch->q.qlen--;
 869		return skb;
 870	}
 871
 872	if (!sch->q.qlen)
 873		goto fin;
 874	q->now = psched_get_time();
 875	start_at = jiffies;
 876
 877	next_event = q->now + 5 * PSCHED_TICKS_PER_SEC;
 878
 879	for (level = 0; level < TC_HTB_MAXDEPTH; level++) {
 880		/* common case optimization - skip event handler quickly */
 881		int m;
 882		psched_time_t event;
 883
 884		if (q->now >= q->near_ev_cache[level]) {
 885			event = htb_do_events(q, level, start_at);
 886			if (!event)
 887				event = q->now + PSCHED_TICKS_PER_SEC;
 888			q->near_ev_cache[level] = event;
 889		} else
 890			event = q->near_ev_cache[level];
 891
 892		if (next_event > event)
 893			next_event = event;
 894
 895		m = ~q->row_mask[level];
 896		while (m != (int)(-1)) {
 897			int prio = ffz(m);
 898
 899			m |= 1 << prio;
 900			skb = htb_dequeue_tree(q, prio, level);
 901			if (likely(skb != NULL))
 902				goto ok;
 903		}
 904	}
 905	sch->qstats.overlimits++;
 906	if (likely(next_event > q->now))
 907		qdisc_watchdog_schedule(&q->watchdog, next_event);
 908	else
 909		schedule_work(&q->work);
 910fin:
 911	return skb;
 912}
 913
 914/* try to drop from each class (by prio) until one succeed */
 915static unsigned int htb_drop(struct Qdisc *sch)
 916{
 917	struct htb_sched *q = qdisc_priv(sch);
 918	int prio;
 919
 920	for (prio = TC_HTB_NUMPRIO - 1; prio >= 0; prio--) {
 921		struct list_head *p;
 922		list_for_each(p, q->drops + prio) {
 923			struct htb_class *cl = list_entry(p, struct htb_class,
 924							  un.leaf.drop_list);
 925			unsigned int len;
 926			if (cl->un.leaf.q->ops->drop &&
 927			    (len = cl->un.leaf.q->ops->drop(cl->un.leaf.q))) {
 928				sch->q.qlen--;
 929				if (!cl->un.leaf.q->q.qlen)
 930					htb_deactivate(q, cl);
 931				return len;
 932			}
 933		}
 934	}
 935	return 0;
 936}
 937
 938/* reset all classes */
 939/* always caled under BH & queue lock */
 940static void htb_reset(struct Qdisc *sch)
 941{
 942	struct htb_sched *q = qdisc_priv(sch);
 943	struct htb_class *cl;
 944	struct hlist_node *n;
 945	unsigned int i;
 946
 947	for (i = 0; i < q->clhash.hashsize; i++) {
 948		hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode) {
 949			if (cl->level)
 950				memset(&cl->un.inner, 0, sizeof(cl->un.inner));
 951			else {
 952				if (cl->un.leaf.q)
 953					qdisc_reset(cl->un.leaf.q);
 954				INIT_LIST_HEAD(&cl->un.leaf.drop_list);
 955			}
 956			cl->prio_activity = 0;
 957			cl->cmode = HTB_CAN_SEND;
 958
 959		}
 960	}
 961	qdisc_watchdog_cancel(&q->watchdog);
 962	__skb_queue_purge(&q->direct_queue);
 963	sch->q.qlen = 0;
 964	memset(q->row, 0, sizeof(q->row));
 
 965	memset(q->row_mask, 0, sizeof(q->row_mask));
 966	memset(q->wait_pq, 0, sizeof(q->wait_pq));
 967	memset(q->ptr, 0, sizeof(q->ptr));
 968	for (i = 0; i < TC_HTB_NUMPRIO; i++)
 969		INIT_LIST_HEAD(q->drops + i);
 970}
 971
 972static const struct nla_policy htb_policy[TCA_HTB_MAX + 1] = {
 973	[TCA_HTB_PARMS]	= { .len = sizeof(struct tc_htb_opt) },
 974	[TCA_HTB_INIT]	= { .len = sizeof(struct tc_htb_glob) },
 975	[TCA_HTB_CTAB]	= { .type = NLA_BINARY, .len = TC_RTAB_SIZE },
 976	[TCA_HTB_RTAB]	= { .type = NLA_BINARY, .len = TC_RTAB_SIZE },
 
 
 
 977};
 978
 979static void htb_work_func(struct work_struct *work)
 980{
 981	struct htb_sched *q = container_of(work, struct htb_sched, work);
 982	struct Qdisc *sch = q->watchdog.qdisc;
 983
 
 984	__netif_schedule(qdisc_root(sch));
 
 985}
 986
 987static int htb_init(struct Qdisc *sch, struct nlattr *opt)
 988{
 989	struct htb_sched *q = qdisc_priv(sch);
 990	struct nlattr *tb[TCA_HTB_INIT + 1];
 991	struct tc_htb_glob *gopt;
 992	int err;
 993	int i;
 994
 995	if (!opt)
 996		return -EINVAL;
 997
 998	err = nla_parse_nested(tb, TCA_HTB_INIT, opt, htb_policy);
 999	if (err < 0)
1000		return err;
1001
1002	if (tb[TCA_HTB_INIT] == NULL) {
1003		pr_err("HTB: hey probably you have bad tc tool ?\n");
1004		return -EINVAL;
1005	}
1006	gopt = nla_data(tb[TCA_HTB_INIT]);
1007	if (gopt->version != HTB_VER >> 16) {
1008		pr_err("HTB: need tc/htb version %d (minor is %d), you have %d\n",
1009		       HTB_VER >> 16, HTB_VER & 0xffff, gopt->version);
1010		return -EINVAL;
1011	}
1012
1013	err = qdisc_class_hash_init(&q->clhash);
1014	if (err < 0)
1015		return err;
1016	for (i = 0; i < TC_HTB_NUMPRIO; i++)
1017		INIT_LIST_HEAD(q->drops + i);
1018
1019	qdisc_watchdog_init(&q->watchdog, sch);
1020	INIT_WORK(&q->work, htb_work_func);
1021	skb_queue_head_init(&q->direct_queue);
1022
1023	q->direct_qlen = qdisc_dev(sch)->tx_queue_len;
1024	if (q->direct_qlen < 2)	/* some devices have zero tx_queue_len */
1025		q->direct_qlen = 2;
 
1026
1027	if ((q->rate2quantum = gopt->rate2quantum) < 1)
1028		q->rate2quantum = 1;
1029	q->defcls = gopt->defcls;
1030
1031	return 0;
1032}
1033
1034static int htb_dump(struct Qdisc *sch, struct sk_buff *skb)
1035{
1036	spinlock_t *root_lock = qdisc_root_sleeping_lock(sch);
1037	struct htb_sched *q = qdisc_priv(sch);
1038	struct nlattr *nest;
1039	struct tc_htb_glob gopt;
1040
1041	spin_lock_bh(root_lock);
 
 
1042
1043	gopt.direct_pkts = q->direct_pkts;
1044	gopt.version = HTB_VER;
1045	gopt.rate2quantum = q->rate2quantum;
1046	gopt.defcls = q->defcls;
1047	gopt.debug = 0;
1048
1049	nest = nla_nest_start(skb, TCA_OPTIONS);
1050	if (nest == NULL)
1051		goto nla_put_failure;
1052	if (nla_put(skb, TCA_HTB_INIT, sizeof(gopt), &gopt))
 
1053		goto nla_put_failure;
1054	nla_nest_end(skb, nest);
1055
1056	spin_unlock_bh(root_lock);
1057	return skb->len;
1058
1059nla_put_failure:
1060	spin_unlock_bh(root_lock);
1061	nla_nest_cancel(skb, nest);
1062	return -1;
1063}
1064
1065static int htb_dump_class(struct Qdisc *sch, unsigned long arg,
1066			  struct sk_buff *skb, struct tcmsg *tcm)
1067{
1068	struct htb_class *cl = (struct htb_class *)arg;
1069	spinlock_t *root_lock = qdisc_root_sleeping_lock(sch);
1070	struct nlattr *nest;
1071	struct tc_htb_opt opt;
1072
1073	spin_lock_bh(root_lock);
 
 
1074	tcm->tcm_parent = cl->parent ? cl->parent->common.classid : TC_H_ROOT;
1075	tcm->tcm_handle = cl->common.classid;
1076	if (!cl->level && cl->un.leaf.q)
1077		tcm->tcm_info = cl->un.leaf.q->handle;
1078
1079	nest = nla_nest_start(skb, TCA_OPTIONS);
1080	if (nest == NULL)
1081		goto nla_put_failure;
1082
1083	memset(&opt, 0, sizeof(opt));
1084
1085	opt.rate = cl->rate->rate;
1086	opt.buffer = cl->buffer;
1087	opt.ceil = cl->ceil->rate;
1088	opt.cbuffer = cl->cbuffer;
1089	opt.quantum = cl->quantum;
1090	opt.prio = cl->prio;
1091	opt.level = cl->level;
1092	if (nla_put(skb, TCA_HTB_PARMS, sizeof(opt), &opt))
1093		goto nla_put_failure;
 
 
 
 
 
 
 
 
1094
1095	nla_nest_end(skb, nest);
1096	spin_unlock_bh(root_lock);
1097	return skb->len;
1098
1099nla_put_failure:
1100	spin_unlock_bh(root_lock);
1101	nla_nest_cancel(skb, nest);
1102	return -1;
1103}
1104
1105static int
1106htb_dump_class_stats(struct Qdisc *sch, unsigned long arg, struct gnet_dump *d)
1107{
1108	struct htb_class *cl = (struct htb_class *)arg;
 
 
 
 
1109
1110	if (!cl->level && cl->un.leaf.q)
1111		cl->qstats.qlen = cl->un.leaf.q->q.qlen;
1112	cl->xstats.tokens = cl->tokens;
1113	cl->xstats.ctokens = cl->ctokens;
1114
1115	if (gnet_stats_copy_basic(d, &cl->bstats) < 0 ||
1116	    gnet_stats_copy_rate_est(d, NULL, &cl->rate_est) < 0 ||
1117	    gnet_stats_copy_queue(d, &cl->qstats) < 0)
 
 
 
 
 
1118		return -1;
1119
1120	return gnet_stats_copy_app(d, &cl->xstats, sizeof(cl->xstats));
1121}
1122
1123static int htb_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
1124		     struct Qdisc **old)
1125{
1126	struct htb_class *cl = (struct htb_class *)arg;
1127
1128	if (cl->level)
1129		return -EINVAL;
1130	if (new == NULL &&
1131	    (new = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
1132				     cl->common.classid)) == NULL)
1133		return -ENOBUFS;
1134
1135	sch_tree_lock(sch);
1136	*old = cl->un.leaf.q;
1137	cl->un.leaf.q = new;
1138	if (*old != NULL) {
1139		qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
1140		qdisc_reset(*old);
1141	}
1142	sch_tree_unlock(sch);
1143	return 0;
1144}
1145
1146static struct Qdisc *htb_leaf(struct Qdisc *sch, unsigned long arg)
1147{
1148	struct htb_class *cl = (struct htb_class *)arg;
1149	return !cl->level ? cl->un.leaf.q : NULL;
1150}
1151
1152static void htb_qlen_notify(struct Qdisc *sch, unsigned long arg)
1153{
1154	struct htb_class *cl = (struct htb_class *)arg;
1155
1156	if (cl->un.leaf.q->q.qlen == 0)
1157		htb_deactivate(qdisc_priv(sch), cl);
1158}
1159
1160static unsigned long htb_get(struct Qdisc *sch, u32 classid)
1161{
1162	struct htb_class *cl = htb_find(classid, sch);
1163	if (cl)
1164		cl->refcnt++;
1165	return (unsigned long)cl;
1166}
1167
1168static inline int htb_parent_last_child(struct htb_class *cl)
1169{
1170	if (!cl->parent)
1171		/* the root class */
1172		return 0;
1173	if (cl->parent->children > 1)
1174		/* not the last child */
1175		return 0;
1176	return 1;
1177}
1178
1179static void htb_parent_to_leaf(struct htb_sched *q, struct htb_class *cl,
1180			       struct Qdisc *new_q)
1181{
1182	struct htb_class *parent = cl->parent;
1183
1184	WARN_ON(cl->level || !cl->un.leaf.q || cl->prio_activity);
1185
1186	if (parent->cmode != HTB_CAN_SEND)
1187		htb_safe_rb_erase(&parent->pq_node, q->wait_pq + parent->level);
 
1188
1189	parent->level = 0;
1190	memset(&parent->un.inner, 0, sizeof(parent->un.inner));
1191	INIT_LIST_HEAD(&parent->un.leaf.drop_list);
1192	parent->un.leaf.q = new_q ? new_q : &noop_qdisc;
1193	parent->tokens = parent->buffer;
1194	parent->ctokens = parent->cbuffer;
1195	parent->t_c = psched_get_time();
1196	parent->cmode = HTB_CAN_SEND;
1197}
1198
1199static void htb_destroy_class(struct Qdisc *sch, struct htb_class *cl)
1200{
1201	if (!cl->level) {
1202		WARN_ON(!cl->un.leaf.q);
1203		qdisc_destroy(cl->un.leaf.q);
1204	}
1205	gen_kill_estimator(&cl->bstats, &cl->rate_est);
1206	qdisc_put_rtab(cl->rate);
1207	qdisc_put_rtab(cl->ceil);
1208
1209	tcf_destroy_chain(&cl->filter_list);
1210	kfree(cl);
1211}
1212
1213static void htb_destroy(struct Qdisc *sch)
1214{
1215	struct htb_sched *q = qdisc_priv(sch);
1216	struct hlist_node *n, *next;
1217	struct htb_class *cl;
1218	unsigned int i;
1219
1220	cancel_work_sync(&q->work);
1221	qdisc_watchdog_cancel(&q->watchdog);
1222	/* This line used to be after htb_destroy_class call below
1223	 * and surprisingly it worked in 2.4. But it must precede it
1224	 * because filter need its target class alive to be able to call
1225	 * unbind_filter on it (without Oops).
1226	 */
1227	tcf_destroy_chain(&q->filter_list);
1228
1229	for (i = 0; i < q->clhash.hashsize; i++) {
1230		hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode)
1231			tcf_destroy_chain(&cl->filter_list);
1232	}
1233	for (i = 0; i < q->clhash.hashsize; i++) {
1234		hlist_for_each_entry_safe(cl, n, next, &q->clhash.hash[i],
1235					  common.hnode)
1236			htb_destroy_class(sch, cl);
1237	}
1238	qdisc_class_hash_destroy(&q->clhash);
1239	__skb_queue_purge(&q->direct_queue);
1240}
1241
1242static int htb_delete(struct Qdisc *sch, unsigned long arg)
1243{
1244	struct htb_sched *q = qdisc_priv(sch);
1245	struct htb_class *cl = (struct htb_class *)arg;
1246	unsigned int qlen;
1247	struct Qdisc *new_q = NULL;
1248	int last_child = 0;
1249
1250	// TODO: why don't allow to delete subtree ? references ? does
1251	// tc subsys quarantee us that in htb_destroy it holds no class
1252	// refs so that we can remove children safely there ?
 
1253	if (cl->children || cl->filter_cnt)
1254		return -EBUSY;
1255
1256	if (!cl->level && htb_parent_last_child(cl)) {
1257		new_q = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
1258					  cl->parent->common.classid);
1259		last_child = 1;
1260	}
1261
1262	sch_tree_lock(sch);
1263
1264	if (!cl->level) {
1265		qlen = cl->un.leaf.q->q.qlen;
 
 
1266		qdisc_reset(cl->un.leaf.q);
1267		qdisc_tree_decrease_qlen(cl->un.leaf.q, qlen);
1268	}
1269
1270	/* delete from hash and active; remainder in destroy_class */
1271	qdisc_class_hash_remove(&q->clhash, &cl->common);
1272	if (cl->parent)
1273		cl->parent->children--;
1274
1275	if (cl->prio_activity)
1276		htb_deactivate(q, cl);
1277
1278	if (cl->cmode != HTB_CAN_SEND)
1279		htb_safe_rb_erase(&cl->pq_node, q->wait_pq + cl->level);
 
1280
1281	if (last_child)
1282		htb_parent_to_leaf(q, cl, new_q);
1283
1284	BUG_ON(--cl->refcnt == 0);
1285	/*
1286	 * This shouldn't happen: we "hold" one cops->get() when called
1287	 * from tc_ctl_tclass; the destroy method is done from cops->put().
1288	 */
1289
1290	sch_tree_unlock(sch);
1291	return 0;
1292}
1293
1294static void htb_put(struct Qdisc *sch, unsigned long arg)
1295{
1296	struct htb_class *cl = (struct htb_class *)arg;
1297
1298	if (--cl->refcnt == 0)
1299		htb_destroy_class(sch, cl);
1300}
1301
1302static int htb_change_class(struct Qdisc *sch, u32 classid,
1303			    u32 parentid, struct nlattr **tca,
1304			    unsigned long *arg)
1305{
1306	int err = -EINVAL;
1307	struct htb_sched *q = qdisc_priv(sch);
1308	struct htb_class *cl = (struct htb_class *)*arg, *parent;
1309	struct nlattr *opt = tca[TCA_OPTIONS];
1310	struct qdisc_rate_table *rtab = NULL, *ctab = NULL;
1311	struct nlattr *tb[__TCA_HTB_MAX];
1312	struct tc_htb_opt *hopt;
 
1313
1314	/* extract all subattrs from opt attr */
1315	if (!opt)
1316		goto failure;
1317
1318	err = nla_parse_nested(tb, TCA_HTB_MAX, opt, htb_policy);
1319	if (err < 0)
1320		goto failure;
1321
1322	err = -EINVAL;
1323	if (tb[TCA_HTB_PARMS] == NULL)
1324		goto failure;
1325
1326	parent = parentid == TC_H_ROOT ? NULL : htb_find(parentid, sch);
1327
1328	hopt = nla_data(tb[TCA_HTB_PARMS]);
1329
1330	rtab = qdisc_get_rtab(&hopt->rate, tb[TCA_HTB_RTAB]);
1331	ctab = qdisc_get_rtab(&hopt->ceil, tb[TCA_HTB_CTAB]);
1332	if (!rtab || !ctab)
1333		goto failure;
1334
 
 
 
 
 
 
 
1335	if (!cl) {		/* new class */
1336		struct Qdisc *new_q;
1337		int prio;
1338		struct {
1339			struct nlattr		nla;
1340			struct gnet_estimator	opt;
1341		} est = {
1342			.nla = {
1343				.nla_len	= nla_attr_size(sizeof(est.opt)),
1344				.nla_type	= TCA_RATE,
1345			},
1346			.opt = {
1347				/* 4s interval, 16s averaging constant */
1348				.interval	= 2,
1349				.ewma_log	= 2,
1350			},
1351		};
1352
1353		/* check for valid classid */
1354		if (!classid || TC_H_MAJ(classid ^ sch->handle) ||
1355		    htb_find(classid, sch))
1356			goto failure;
1357
1358		/* check maximal depth */
1359		if (parent && parent->parent && parent->parent->level < 2) {
1360			pr_err("htb: tree is too deep\n");
1361			goto failure;
1362		}
1363		err = -ENOBUFS;
1364		cl = kzalloc(sizeof(*cl), GFP_KERNEL);
1365		if (!cl)
1366			goto failure;
1367
1368		err = gen_new_estimator(&cl->bstats, &cl->rate_est,
1369					qdisc_root_sleeping_lock(sch),
1370					tca[TCA_RATE] ? : &est.nla);
1371		if (err) {
1372			kfree(cl);
1373			goto failure;
 
 
 
 
1374		}
1375
1376		cl->refcnt = 1;
1377		cl->children = 0;
1378		INIT_LIST_HEAD(&cl->un.leaf.drop_list);
1379		RB_CLEAR_NODE(&cl->pq_node);
1380
1381		for (prio = 0; prio < TC_HTB_NUMPRIO; prio++)
1382			RB_CLEAR_NODE(&cl->node[prio]);
1383
1384		/* create leaf qdisc early because it uses kmalloc(GFP_KERNEL)
1385		 * so that can't be used inside of sch_tree_lock
1386		 * -- thanks to Karlis Peisenieks
1387		 */
1388		new_q = qdisc_create_dflt(sch->dev_queue,
1389					  &pfifo_qdisc_ops, classid);
1390		sch_tree_lock(sch);
1391		if (parent && !parent->level) {
1392			unsigned int qlen = parent->un.leaf.q->q.qlen;
 
1393
1394			/* turn parent into inner node */
1395			qdisc_reset(parent->un.leaf.q);
1396			qdisc_tree_decrease_qlen(parent->un.leaf.q, qlen);
1397			qdisc_destroy(parent->un.leaf.q);
1398			if (parent->prio_activity)
1399				htb_deactivate(q, parent);
1400
1401			/* remove from evt list because of level change */
1402			if (parent->cmode != HTB_CAN_SEND) {
1403				htb_safe_rb_erase(&parent->pq_node, q->wait_pq);
1404				parent->cmode = HTB_CAN_SEND;
1405			}
1406			parent->level = (parent->parent ? parent->parent->level
1407					 : TC_HTB_MAXDEPTH) - 1;
1408			memset(&parent->un.inner, 0, sizeof(parent->un.inner));
1409		}
1410		/* leaf (we) needs elementary qdisc */
1411		cl->un.leaf.q = new_q ? new_q : &noop_qdisc;
1412
1413		cl->common.classid = classid;
1414		cl->parent = parent;
1415
1416		/* set class to be in HTB_CAN_SEND state */
1417		cl->tokens = hopt->buffer;
1418		cl->ctokens = hopt->cbuffer;
1419		cl->mbuffer = 60 * PSCHED_TICKS_PER_SEC;	/* 1min */
1420		cl->t_c = psched_get_time();
1421		cl->cmode = HTB_CAN_SEND;
1422
1423		/* attach to the hash list and parent's family */
1424		qdisc_class_hash_insert(&q->clhash, &cl->common);
1425		if (parent)
1426			parent->children++;
1427	} else {
1428		if (tca[TCA_RATE]) {
1429			err = gen_replace_estimator(&cl->bstats, &cl->rate_est,
1430						    qdisc_root_sleeping_lock(sch),
 
 
1431						    tca[TCA_RATE]);
1432			if (err)
1433				return err;
1434		}
1435		sch_tree_lock(sch);
1436	}
1437
 
 
 
 
 
 
 
1438	/* it used to be a nasty bug here, we have to check that node
1439	 * is really leaf before changing cl->un.leaf !
1440	 */
1441	if (!cl->level) {
1442		cl->quantum = rtab->rate.rate / q->rate2quantum;
 
 
 
 
1443		if (!hopt->quantum && cl->quantum < 1000) {
1444			pr_warning(
1445			       "HTB: quantum of class %X is small. Consider r2q change.\n",
1446			       cl->common.classid);
1447			cl->quantum = 1000;
1448		}
1449		if (!hopt->quantum && cl->quantum > 200000) {
1450			pr_warning(
1451			       "HTB: quantum of class %X is big. Consider r2q change.\n",
1452			       cl->common.classid);
1453			cl->quantum = 200000;
1454		}
1455		if (hopt->quantum)
1456			cl->quantum = hopt->quantum;
1457		if ((cl->prio = hopt->prio) >= TC_HTB_NUMPRIO)
1458			cl->prio = TC_HTB_NUMPRIO - 1;
1459	}
1460
1461	cl->buffer = hopt->buffer;
1462	cl->cbuffer = hopt->cbuffer;
1463	if (cl->rate)
1464		qdisc_put_rtab(cl->rate);
1465	cl->rate = rtab;
1466	if (cl->ceil)
1467		qdisc_put_rtab(cl->ceil);
1468	cl->ceil = ctab;
1469	sch_tree_unlock(sch);
1470
1471	qdisc_class_hash_grow(sch, &q->clhash);
1472
1473	*arg = (unsigned long)cl;
1474	return 0;
1475
1476failure:
1477	if (rtab)
1478		qdisc_put_rtab(rtab);
1479	if (ctab)
1480		qdisc_put_rtab(ctab);
1481	return err;
1482}
1483
1484static struct tcf_proto **htb_find_tcf(struct Qdisc *sch, unsigned long arg)
 
1485{
1486	struct htb_sched *q = qdisc_priv(sch);
1487	struct htb_class *cl = (struct htb_class *)arg;
1488	struct tcf_proto **fl = cl ? &cl->filter_list : &q->filter_list;
1489
1490	return fl;
1491}
1492
1493static unsigned long htb_bind_filter(struct Qdisc *sch, unsigned long parent,
1494				     u32 classid)
1495{
1496	struct htb_class *cl = htb_find(classid, sch);
1497
1498	/*if (cl && !cl->level) return 0;
1499	 * The line above used to be there to prevent attaching filters to
1500	 * leaves. But at least tc_index filter uses this just to get class
1501	 * for other reasons so that we have to allow for it.
1502	 * ----
1503	 * 19.6.2002 As Werner explained it is ok - bind filter is just
1504	 * another way to "lock" the class - unlike "get" this lock can
1505	 * be broken by class during destroy IIUC.
1506	 */
1507	if (cl)
1508		cl->filter_cnt++;
1509	return (unsigned long)cl;
1510}
1511
1512static void htb_unbind_filter(struct Qdisc *sch, unsigned long arg)
1513{
1514	struct htb_class *cl = (struct htb_class *)arg;
1515
1516	if (cl)
1517		cl->filter_cnt--;
1518}
1519
1520static void htb_walk(struct Qdisc *sch, struct qdisc_walker *arg)
1521{
1522	struct htb_sched *q = qdisc_priv(sch);
1523	struct htb_class *cl;
1524	struct hlist_node *n;
1525	unsigned int i;
1526
1527	if (arg->stop)
1528		return;
1529
1530	for (i = 0; i < q->clhash.hashsize; i++) {
1531		hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode) {
1532			if (arg->count < arg->skip) {
1533				arg->count++;
1534				continue;
1535			}
1536			if (arg->fn(sch, (unsigned long)cl, arg) < 0) {
1537				arg->stop = 1;
1538				return;
1539			}
1540			arg->count++;
1541		}
1542	}
1543}
1544
1545static const struct Qdisc_class_ops htb_class_ops = {
1546	.graft		=	htb_graft,
1547	.leaf		=	htb_leaf,
1548	.qlen_notify	=	htb_qlen_notify,
1549	.get		=	htb_get,
1550	.put		=	htb_put,
1551	.change		=	htb_change_class,
1552	.delete		=	htb_delete,
1553	.walk		=	htb_walk,
1554	.tcf_chain	=	htb_find_tcf,
1555	.bind_tcf	=	htb_bind_filter,
1556	.unbind_tcf	=	htb_unbind_filter,
1557	.dump		=	htb_dump_class,
1558	.dump_stats	=	htb_dump_class_stats,
1559};
1560
1561static struct Qdisc_ops htb_qdisc_ops __read_mostly = {
1562	.cl_ops		=	&htb_class_ops,
1563	.id		=	"htb",
1564	.priv_size	=	sizeof(struct htb_sched),
1565	.enqueue	=	htb_enqueue,
1566	.dequeue	=	htb_dequeue,
1567	.peek		=	qdisc_peek_dequeued,
1568	.drop		=	htb_drop,
1569	.init		=	htb_init,
1570	.reset		=	htb_reset,
1571	.destroy	=	htb_destroy,
1572	.dump		=	htb_dump,
1573	.owner		=	THIS_MODULE,
1574};
1575
1576static int __init htb_module_init(void)
1577{
1578	return register_qdisc(&htb_qdisc_ops);
1579}
1580static void __exit htb_module_exit(void)
1581{
1582	unregister_qdisc(&htb_qdisc_ops);
1583}
1584
1585module_init(htb_module_init)
1586module_exit(htb_module_exit)
1587MODULE_LICENSE("GPL");