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