net/sched/sch_api.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * net/sched/sch_api.c  Packet scheduler API.
   4  *
   5  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
   6  *
   7  * Fixes:
   8  *
   9  * Rani Assaf <rani@magic.metawire.com> :980802: JIFFIES and CPU clock sources are repaired.
  10  * Eduardo J. Blanco <ejbs@netlabs.com.uy> :990222: kmod support
  11  * Jamal Hadi Salim <hadi@nortelnetworks.com>: 990601: ingress support
  12  */
  13
  14 #include <linux/module.h>
  15 #include <linux/types.h>
  16 #include <linux/kernel.h>
  17 #include <linux/string.h>
  18 #include <linux/errno.h>
  19 #include <linux/skbuff.h>
  20 #include <linux/init.h>
  21 #include <linux/proc_fs.h>
  22 #include <linux/seq_file.h>
  23 #include <linux/kmod.h>
  24 #include <linux/list.h>
  25 #include <linux/hrtimer.h>
  26 #include <linux/slab.h>
  27 #include <linux/hashtable.h>
  28
  29 #include <net/net_namespace.h>
  30 #include <net/sock.h>
  31 #include <net/netlink.h>
  32 #include <net/pkt_sched.h>
  33 #include <net/pkt_cls.h>
  34
  35 #include <trace/events/qdisc.h>
  36
  37 /*
  38
  39    Short review.
  40    -------------
  41
  42    This file consists of two interrelated parts:
  43
  44    1. queueing disciplines manager frontend.
  45    2. traffic classes manager frontend.
  46
  47    Generally, queueing discipline ("qdisc") is a black box,
  48    which is able to enqueue packets and to dequeue them (when
  49    device is ready to send something) in order and at times
  50    determined by algorithm hidden in it.
  51
  52    qdisc's are divided to two categories:
  53    - "queues", which have no internal structure visible from outside.
  54    - "schedulers", which split all the packets to "traffic classes",
  55      using "packet classifiers" (look at cls_api.c)
  56
  57    In turn, classes may have child qdiscs (as rule, queues)
  58    attached to them etc. etc. etc.
  59
  60    The goal of the routines in this file is to translate
  61    information supplied by user in the form of handles
  62    to more intelligible for kernel form, to make some sanity
  63    checks and part of work, which is common to all qdiscs
  64    and to provide rtnetlink notifications.
  65
  66    All real intelligent work is done inside qdisc modules.
  67
  68
  69
  70    Every discipline has two major routines: enqueue and dequeue.
  71
  72    ---dequeue
  73
  74    dequeue usually returns a skb to send. It is allowed to return NULL,
  75    but it does not mean that queue is empty, it just means that
  76    discipline does not want to send anything this time.
  77    Queue is really empty if q->q.qlen == 0.
  78    For complicated disciplines with multiple queues q->q is not
  79    real packet queue, but however q->q.qlen must be valid.
  80
  81    ---enqueue
  82
  83    enqueue returns 0, if packet was enqueued successfully.
  84    If packet (this one or another one) was dropped, it returns
  85    not zero error code.
  86    NET_XMIT_DROP        - this packet dropped
  87      Expected action: do not backoff, but wait until queue will clear.
  88    NET_XMIT_CN          - probably this packet enqueued, but another one dropped.
  89      Expected action: backoff or ignore
  90
  91    Auxiliary routines:
  92
  93    ---peek
  94
  95    like dequeue but without removing a packet from the queue
  96
  97    ---reset
  98
  99    returns qdisc to initial state: purge all buffers, clear all
 100    timers, counters (except for statistics) etc.
 101
 102    ---init
 103
 104    initializes newly created qdisc.
 105
 106    ---destroy
 107
 108    destroys resources allocated by init and during lifetime of qdisc.
 109
 110    ---change
 111
 112    changes qdisc parameters.
 113  */
 114
 115 /* Protects list of registered TC modules. It is pure SMP lock. */
 116 static DEFINE_RWLOCK(qdisc_mod_lock);
 117
 118
 119 /************************************************
 120  *      Queueing disciplines manipulation.      *
 121  ************************************************/
 122
 123
 124 /* The list of all installed queueing disciplines. */
 125
 126 static struct Qdisc_ops *qdisc_base;
 127
 128 /* Register/unregister queueing discipline */
 129
 130 int register_qdisc(struct Qdisc_ops *qops)
 131 {
 132         struct Qdisc_ops *q, **qp;
 133         int rc = -EEXIST;
 134
 135         write_lock(&qdisc_mod_lock);
 136         for (qp = &qdisc_base; (q = *qp) != NULL; qp = &q->next)
 137                 if (!strcmp(qops->id, q->id))
 138                         goto out;
 139
 140         if (qops->enqueue == NULL)
 141                 qops->enqueue = noop_qdisc_ops.enqueue;
 142         if (qops->peek == NULL) {
 143                 if (qops->dequeue == NULL)
 144                         qops->peek = noop_qdisc_ops.peek;
 145                 else
 146                         goto out_einval;
 147         }
 148         if (qops->dequeue == NULL)
 149                 qops->dequeue = noop_qdisc_ops.dequeue;
 150
 151         if (qops->cl_ops) {
 152                 const struct Qdisc_class_ops *cops = qops->cl_ops;
 153
 154                 if (!(cops->find && cops->walk && cops->leaf))
 155                         goto out_einval;
 156
 157                 if (cops->tcf_block && !(cops->bind_tcf && cops->unbind_tcf))
 158                         goto out_einval;
 159         }
 160
 161         qops->next = NULL;
 162         *qp = qops;
 163         rc = 0;
 164 out:
 165         write_unlock(&qdisc_mod_lock);
 166         return rc;
 167
 168 out_einval:
 169         rc = -EINVAL;
 170         goto out;
 171 }
 172 EXPORT_SYMBOL(register_qdisc);
 173
 174 void unregister_qdisc(struct Qdisc_ops *qops)
 175 {
 176         struct Qdisc_ops *q, **qp;
 177         int err = -ENOENT;
 178
 179         write_lock(&qdisc_mod_lock);
 180         for (qp = &qdisc_base; (q = *qp) != NULL; qp = &q->next)
 181                 if (q == qops)
 182                         break;
 183         if (q) {
 184                 *qp = q->next;
 185                 q->next = NULL;
 186                 err = 0;
 187         }
 188         write_unlock(&qdisc_mod_lock);
 189
 190         WARN(err, "unregister qdisc(%s) failed\n", qops->id);
 191 }
 192 EXPORT_SYMBOL(unregister_qdisc);
 193
 194 /* Get default qdisc if not otherwise specified */
 195 void qdisc_get_default(char *name, size_t len)
 196 {
 197         read_lock(&qdisc_mod_lock);
 198         strscpy(name, default_qdisc_ops->id, len);
 199         read_unlock(&qdisc_mod_lock);
 200 }
 201
 202 static struct Qdisc_ops *qdisc_lookup_default(const char *name)
 203 {
 204         struct Qdisc_ops *q = NULL;
 205
 206         for (q = qdisc_base; q; q = q->next) {
 207                 if (!strcmp(name, q->id)) {
 208                         if (!try_module_get(q->owner))
 209                                 q = NULL;
 210                         break;
 211                 }
 212         }
 213
 214         return q;
 215 }
 216
 217 /* Set new default qdisc to use */
 218 int qdisc_set_default(const char *name)
 219 {
 220         const struct Qdisc_ops *ops;
 221
 222         if (!capable(CAP_NET_ADMIN))
 223                 return -EPERM;
 224
 225         write_lock(&qdisc_mod_lock);
 226         ops = qdisc_lookup_default(name);
 227         if (!ops) {
 228                 /* Not found, drop lock and try to load module */
 229                 write_unlock(&qdisc_mod_lock);
 230                 request_module("sch_%s", name);
 231                 write_lock(&qdisc_mod_lock);
 232
 233                 ops = qdisc_lookup_default(name);
 234         }
 235
 236         if (ops) {
 237                 /* Set new default */
 238                 module_put(default_qdisc_ops->owner);
 239                 default_qdisc_ops = ops;
 240         }
 241         write_unlock(&qdisc_mod_lock);
 242
 243         return ops ? 0 : -ENOENT;
 244 }
 245
 246 #ifdef CONFIG_NET_SCH_DEFAULT
 247 /* Set default value from kernel config */
 248 static int __init sch_default_qdisc(void)
 249 {
 250         return qdisc_set_default(CONFIG_DEFAULT_NET_SCH);
 251 }
 252 late_initcall(sch_default_qdisc);
 253 #endif
 254
 255 /* We know handle. Find qdisc among all qdisc's attached to device
 256  * (root qdisc, all its children, children of children etc.)
 257  * Note: caller either uses rtnl or rcu_read_lock()
 258  */
 259
 260 static struct Qdisc *qdisc_match_from_root(struct Qdisc *root, u32 handle)
 261 {
 262         struct Qdisc *q;
 263
 264         if (!qdisc_dev(root))
 265                 return (root->handle == handle ? root : NULL);
 266
 267         if (!(root->flags & TCQ_F_BUILTIN) &&
 268             root->handle == handle)
 269                 return root;
 270
 271         hash_for_each_possible_rcu(qdisc_dev(root)->qdisc_hash, q, hash, handle,
 272                                    lockdep_rtnl_is_held()) {
 273                 if (q->handle == handle)
 274                         return q;
 275         }
 276         return NULL;
 277 }
 278
 279 void qdisc_hash_add(struct Qdisc *q, bool invisible)
 280 {
 281         if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS)) {
 282                 ASSERT_RTNL();
 283                 hash_add_rcu(qdisc_dev(q)->qdisc_hash, &q->hash, q->handle);
 284                 if (invisible)
 285                         q->flags |= TCQ_F_INVISIBLE;
 286         }
 287 }
 288 EXPORT_SYMBOL(qdisc_hash_add);
 289
 290 void qdisc_hash_del(struct Qdisc *q)
 291 {
 292         if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS)) {
 293                 ASSERT_RTNL();
 294                 hash_del_rcu(&q->hash);
 295         }
 296 }
 297 EXPORT_SYMBOL(qdisc_hash_del);
 298
 299 struct Qdisc *qdisc_lookup(struct net_device *dev, u32 handle)
 300 {
 301         struct Qdisc *q;
 302
 303         if (!handle)
 304                 return NULL;
 305         q = qdisc_match_from_root(rtnl_dereference(dev->qdisc), handle);
 306         if (q)
 307                 goto out;
 308
 309         if (dev_ingress_queue(dev))
 310                 q = qdisc_match_from_root(
 311                         rtnl_dereference(dev_ingress_queue(dev)->qdisc_sleeping),
 312                         handle);
 313 out:
 314         return q;
 315 }
 316
 317 struct Qdisc *qdisc_lookup_rcu(struct net_device *dev, u32 handle)
 318 {
 319         struct netdev_queue *nq;
 320         struct Qdisc *q;
 321
 322         if (!handle)
 323                 return NULL;
 324         q = qdisc_match_from_root(rcu_dereference(dev->qdisc), handle);
 325         if (q)
 326                 goto out;
 327
 328         nq = dev_ingress_queue_rcu(dev);
 329         if (nq)
 330                 q = qdisc_match_from_root(rcu_dereference(nq->qdisc_sleeping),
 331                                           handle);
 332 out:
 333         return q;
 334 }
 335
 336 static struct Qdisc *qdisc_leaf(struct Qdisc *p, u32 classid)
 337 {
 338         unsigned long cl;
 339         const struct Qdisc_class_ops *cops = p->ops->cl_ops;
 340
 341         if (cops == NULL)
 342                 return NULL;
 343         cl = cops->find(p, classid);
 344
 345         if (cl == 0)
 346                 return NULL;
 347         return cops->leaf(p, cl);
 348 }
 349
 350 /* Find queueing discipline by name */
 351
 352 static struct Qdisc_ops *qdisc_lookup_ops(struct nlattr *kind)
 353 {
 354         struct Qdisc_ops *q = NULL;
 355
 356         if (kind) {
 357                 read_lock(&qdisc_mod_lock);
 358                 for (q = qdisc_base; q; q = q->next) {
 359                         if (nla_strcmp(kind, q->id) == 0) {
 360                                 if (!try_module_get(q->owner))
 361                                         q = NULL;
 362                                 break;
 363                         }
 364                 }
 365                 read_unlock(&qdisc_mod_lock);
 366         }
 367         return q;
 368 }
 369
 370 /* The linklayer setting were not transferred from iproute2, in older
 371  * versions, and the rate tables lookup systems have been dropped in
 372  * the kernel. To keep backward compatible with older iproute2 tc
 373  * utils, we detect the linklayer setting by detecting if the rate
 374  * table were modified.
 375  *
 376  * For linklayer ATM table entries, the rate table will be aligned to
 377  * 48 bytes, thus some table entries will contain the same value.  The
 378  * mpu (min packet unit) is also encoded into the old rate table, thus
 379  * starting from the mpu, we find low and high table entries for
 380  * mapping this cell.  If these entries contain the same value, when
 381  * the rate tables have been modified for linklayer ATM.
 382  *
 383  * This is done by rounding mpu to the nearest 48 bytes cell/entry,
 384  * and then roundup to the next cell, calc the table entry one below,
 385  * and compare.
 386  */
 387 static __u8 __detect_linklayer(struct tc_ratespec *r, __u32 *rtab)
 388 {
 389         int low       = roundup(r->mpu, 48);
 390         int high      = roundup(low+1, 48);
 391         int cell_low  = low >> r->cell_log;
 392         int cell_high = (high >> r->cell_log) - 1;
 393
 394         /* rtab is too inaccurate at rates > 100Mbit/s */
 395         if ((r->rate > (100000000/8)) || (rtab[0] == 0)) {
 396                 pr_debug("TC linklayer: Giving up ATM detection\n");
 397                 return TC_LINKLAYER_ETHERNET;
 398         }
 399
 400         if ((cell_high > cell_low) && (cell_high < 256)
 401             && (rtab[cell_low] == rtab[cell_high])) {
 402                 pr_debug("TC linklayer: Detected ATM, low(%d)=high(%d)=%u\n",
 403                          cell_low, cell_high, rtab[cell_high]);
 404                 return TC_LINKLAYER_ATM;
 405         }
 406         return TC_LINKLAYER_ETHERNET;
 407 }
 408
 409 static struct qdisc_rate_table *qdisc_rtab_list;
 410
 411 struct qdisc_rate_table *qdisc_get_rtab(struct tc_ratespec *r,
 412                                         struct nlattr *tab,
 413                                         struct netlink_ext_ack *extack)
 414 {
 415         struct qdisc_rate_table *rtab;
 416
 417         if (tab == NULL || r->rate == 0 ||
 418             r->cell_log == 0 || r->cell_log >= 32 ||
 419             nla_len(tab) != TC_RTAB_SIZE) {
 420                 NL_SET_ERR_MSG(extack, "Invalid rate table parameters for searching");
 421                 return NULL;
 422         }
 423
 424         for (rtab = qdisc_rtab_list; rtab; rtab = rtab->next) {
 425                 if (!memcmp(&rtab->rate, r, sizeof(struct tc_ratespec)) &&
 426                     !memcmp(&rtab->data, nla_data(tab), 1024)) {
 427                         rtab->refcnt++;
 428                         return rtab;
 429                 }
 430         }
 431
 432         rtab = kmalloc(sizeof(*rtab), GFP_KERNEL);
 433         if (rtab) {
 434                 rtab->rate = *r;
 435                 rtab->refcnt = 1;
 436                 memcpy(rtab->data, nla_data(tab), 1024);
 437                 if (r->linklayer == TC_LINKLAYER_UNAWARE)
 438                         r->linklayer = __detect_linklayer(r, rtab->data);
 439                 rtab->next = qdisc_rtab_list;
 440                 qdisc_rtab_list = rtab;
 441         } else {
 442                 NL_SET_ERR_MSG(extack, "Failed to allocate new qdisc rate table");
 443         }
 444         return rtab;
 445 }
 446 EXPORT_SYMBOL(qdisc_get_rtab);
 447
 448 void qdisc_put_rtab(struct qdisc_rate_table *tab)
 449 {
 450         struct qdisc_rate_table *rtab, **rtabp;
 451
 452         if (!tab || --tab->refcnt)
 453                 return;
 454
 455         for (rtabp = &qdisc_rtab_list;
 456              (rtab = *rtabp) != NULL;
 457              rtabp = &rtab->next) {
 458                 if (rtab == tab) {
 459                         *rtabp = rtab->next;
 460                         kfree(rtab);
 461                         return;
 462                 }
 463         }
 464 }
 465 EXPORT_SYMBOL(qdisc_put_rtab);
 466
 467 static LIST_HEAD(qdisc_stab_list);
 468
 469 static const struct nla_policy stab_policy[TCA_STAB_MAX + 1] = {
 470         [TCA_STAB_BASE] = { .len = sizeof(struct tc_sizespec) },
 471         [TCA_STAB_DATA] = { .type = NLA_BINARY },
 472 };
 473
 474 static struct qdisc_size_table *qdisc_get_stab(struct nlattr *opt,
 475                                                struct netlink_ext_ack *extack)
 476 {
 477         struct nlattr *tb[TCA_STAB_MAX + 1];
 478         struct qdisc_size_table *stab;
 479         struct tc_sizespec *s;
 480         unsigned int tsize = 0;
 481         u16 *tab = NULL;
 482         int err;
 483
 484         err = nla_parse_nested_deprecated(tb, TCA_STAB_MAX, opt, stab_policy,
 485                                           extack);
 486         if (err < 0)
 487                 return ERR_PTR(err);
 488         if (!tb[TCA_STAB_BASE]) {
 489                 NL_SET_ERR_MSG(extack, "Size table base attribute is missing");
 490                 return ERR_PTR(-EINVAL);
 491         }
 492
 493         s = nla_data(tb[TCA_STAB_BASE]);
 494
 495         if (s->tsize > 0) {
 496                 if (!tb[TCA_STAB_DATA]) {
 497                         NL_SET_ERR_MSG(extack, "Size table data attribute is missing");
 498                         return ERR_PTR(-EINVAL);
 499                 }
 500                 tab = nla_data(tb[TCA_STAB_DATA]);
 501                 tsize = nla_len(tb[TCA_STAB_DATA]) / sizeof(u16);
 502         }
 503
 504         if (tsize != s->tsize || (!tab && tsize > 0)) {
 505                 NL_SET_ERR_MSG(extack, "Invalid size of size table");
 506                 return ERR_PTR(-EINVAL);
 507         }
 508
 509         list_for_each_entry(stab, &qdisc_stab_list, list) {
 510                 if (memcmp(&stab->szopts, s, sizeof(*s)))
 511                         continue;
 512                 if (tsize > 0 &&
 513                     memcmp(stab->data, tab, flex_array_size(stab, data, tsize)))
 514                         continue;
 515                 stab->refcnt++;
 516                 return stab;
 517         }
 518
 519         if (s->size_log > STAB_SIZE_LOG_MAX ||
 520             s->cell_log > STAB_SIZE_LOG_MAX) {
 521                 NL_SET_ERR_MSG(extack, "Invalid logarithmic size of size table");
 522                 return ERR_PTR(-EINVAL);
 523         }
 524
 525         stab = kmalloc(struct_size(stab, data, tsize), GFP_KERNEL);
 526         if (!stab)
 527                 return ERR_PTR(-ENOMEM);
 528
 529         stab->refcnt = 1;
 530         stab->szopts = *s;
 531         if (tsize > 0)
 532                 memcpy(stab->data, tab, flex_array_size(stab, data, tsize));
 533
 534         list_add_tail(&stab->list, &qdisc_stab_list);
 535
 536         return stab;
 537 }
 538
 539 void qdisc_put_stab(struct qdisc_size_table *tab)
 540 {
 541         if (!tab)
 542                 return;
 543
 544         if (--tab->refcnt == 0) {
 545                 list_del(&tab->list);
 546                 kfree_rcu(tab, rcu);
 547         }
 548 }
 549 EXPORT_SYMBOL(qdisc_put_stab);
 550
 551 static int qdisc_dump_stab(struct sk_buff *skb, struct qdisc_size_table *stab)
 552 {
 553         struct nlattr *nest;
 554
 555         nest = nla_nest_start_noflag(skb, TCA_STAB);
 556         if (nest == NULL)
 557                 goto nla_put_failure;
 558         if (nla_put(skb, TCA_STAB_BASE, sizeof(stab->szopts), &stab->szopts))
 559                 goto nla_put_failure;
 560         nla_nest_end(skb, nest);
 561
 562         return skb->len;
 563
 564 nla_put_failure:
 565         return -1;
 566 }
 567
 568 void __qdisc_calculate_pkt_len(struct sk_buff *skb,
 569                                const struct qdisc_size_table *stab)
 570 {
 571         int pkt_len, slot;
 572
 573         pkt_len = skb->len + stab->szopts.overhead;
 574         if (unlikely(!stab->szopts.tsize))
 575                 goto out;
 576
 577         slot = pkt_len + stab->szopts.cell_align;
 578         if (unlikely(slot < 0))
 579                 slot = 0;
 580
 581         slot >>= stab->szopts.cell_log;
 582         if (likely(slot < stab->szopts.tsize))
 583                 pkt_len = stab->data[slot];
 584         else
 585                 pkt_len = stab->data[stab->szopts.tsize - 1] *
 586                                 (slot / stab->szopts.tsize) +
 587                                 stab->data[slot % stab->szopts.tsize];
 588
 589         pkt_len <<= stab->szopts.size_log;
 590 out:
 591         if (unlikely(pkt_len < 1))
 592                 pkt_len = 1;
 593         qdisc_skb_cb(skb)->pkt_len = pkt_len;
 594 }
 595 EXPORT_SYMBOL(__qdisc_calculate_pkt_len);
 596
 597 void qdisc_warn_nonwc(const char *txt, struct Qdisc *qdisc)
 598 {
 599         if (!(qdisc->flags & TCQ_F_WARN_NONWC)) {
 600                 pr_warn("%s: %s qdisc %X: is non-work-conserving?\n",
 601                         txt, qdisc->ops->id, qdisc->handle >> 16);
 602                 qdisc->flags |= TCQ_F_WARN_NONWC;
 603         }
 604 }
 605 EXPORT_SYMBOL(qdisc_warn_nonwc);
 606
 607 static enum hrtimer_restart qdisc_watchdog(struct hrtimer *timer)
 608 {
 609         struct qdisc_watchdog *wd = container_of(timer, struct qdisc_watchdog,
 610                                                  timer);
 611
 612         rcu_read_lock();
 613         __netif_schedule(qdisc_root(wd->qdisc));
 614         rcu_read_unlock();
 615
 616         return HRTIMER_NORESTART;
 617 }
 618
 619 void qdisc_watchdog_init_clockid(struct qdisc_watchdog *wd, struct Qdisc *qdisc,
 620                                  clockid_t clockid)
 621 {
 622         hrtimer_init(&wd->timer, clockid, HRTIMER_MODE_ABS_PINNED);
 623         wd->timer.function = qdisc_watchdog;
 624         wd->qdisc = qdisc;
 625 }
 626 EXPORT_SYMBOL(qdisc_watchdog_init_clockid);
 627
 628 void qdisc_watchdog_init(struct qdisc_watchdog *wd, struct Qdisc *qdisc)
 629 {
 630         qdisc_watchdog_init_clockid(wd, qdisc, CLOCK_MONOTONIC);
 631 }
 632 EXPORT_SYMBOL(qdisc_watchdog_init);
 633
 634 void qdisc_watchdog_schedule_range_ns(struct qdisc_watchdog *wd, u64 expires,
 635                                       u64 delta_ns)
 636 {
 637         bool deactivated;
 638
 639         rcu_read_lock();
 640         deactivated = test_bit(__QDISC_STATE_DEACTIVATED,
 641                                &qdisc_root_sleeping(wd->qdisc)->state);
 642         rcu_read_unlock();
 643         if (deactivated)
 644                 return;
 645
 646         if (hrtimer_is_queued(&wd->timer)) {
 647                 /* If timer is already set in [expires, expires + delta_ns],
 648                  * do not reprogram it.
 649                  */
 650                 if (wd->last_expires - expires <= delta_ns)
 651                         return;
 652         }
 653
 654         wd->last_expires = expires;
 655         hrtimer_start_range_ns(&wd->timer,
 656                                ns_to_ktime(expires),
 657                                delta_ns,
 658                                HRTIMER_MODE_ABS_PINNED);
 659 }
 660 EXPORT_SYMBOL(qdisc_watchdog_schedule_range_ns);
 661
 662 void qdisc_watchdog_cancel(struct qdisc_watchdog *wd)
 663 {
 664         hrtimer_cancel(&wd->timer);
 665 }
 666 EXPORT_SYMBOL(qdisc_watchdog_cancel);
 667
 668 static struct hlist_head *qdisc_class_hash_alloc(unsigned int n)
 669 {
 670         struct hlist_head *h;
 671         unsigned int i;
 672
 673         h = kvmalloc_array(n, sizeof(struct hlist_head), GFP_KERNEL);
 674
 675         if (h != NULL) {
 676                 for (i = 0; i < n; i++)
 677                         INIT_HLIST_HEAD(&h[i]);
 678         }
 679         return h;
 680 }
 681
 682 void qdisc_class_hash_grow(struct Qdisc *sch, struct Qdisc_class_hash *clhash)
 683 {
 684         struct Qdisc_class_common *cl;
 685         struct hlist_node *next;
 686         struct hlist_head *nhash, *ohash;
 687         unsigned int nsize, nmask, osize;
 688         unsigned int i, h;
 689
 690         /* Rehash when load factor exceeds 0.75 */
 691         if (clhash->hashelems * 4 <= clhash->hashsize * 3)
 692                 return;
 693         nsize = clhash->hashsize * 2;
 694         nmask = nsize - 1;
 695         nhash = qdisc_class_hash_alloc(nsize);
 696         if (nhash == NULL)
 697                 return;
 698
 699         ohash = clhash->hash;
 700         osize = clhash->hashsize;
 701
 702         sch_tree_lock(sch);
 703         for (i = 0; i < osize; i++) {
 704                 hlist_for_each_entry_safe(cl, next, &ohash[i], hnode) {
 705                         h = qdisc_class_hash(cl->classid, nmask);
 706                         hlist_add_head(&cl->hnode, &nhash[h]);
 707                 }
 708         }
 709         clhash->hash     = nhash;
 710         clhash->hashsize = nsize;
 711         clhash->hashmask = nmask;
 712         sch_tree_unlock(sch);
 713
 714         kvfree(ohash);
 715 }
 716 EXPORT_SYMBOL(qdisc_class_hash_grow);
 717
 718 int qdisc_class_hash_init(struct Qdisc_class_hash *clhash)
 719 {
 720         unsigned int size = 4;
 721
 722         clhash->hash = qdisc_class_hash_alloc(size);
 723         if (!clhash->hash)
 724                 return -ENOMEM;
 725         clhash->hashsize  = size;
 726         clhash->hashmask  = size - 1;
 727         clhash->hashelems = 0;
 728         return 0;
 729 }
 730 EXPORT_SYMBOL(qdisc_class_hash_init);
 731
 732 void qdisc_class_hash_destroy(struct Qdisc_class_hash *clhash)
 733 {
 734         kvfree(clhash->hash);
 735 }
 736 EXPORT_SYMBOL(qdisc_class_hash_destroy);
 737
 738 void qdisc_class_hash_insert(struct Qdisc_class_hash *clhash,
 739                              struct Qdisc_class_common *cl)
 740 {
 741         unsigned int h;
 742
 743         INIT_HLIST_NODE(&cl->hnode);
 744         h = qdisc_class_hash(cl->classid, clhash->hashmask);
 745         hlist_add_head(&cl->hnode, &clhash->hash[h]);
 746         clhash->hashelems++;
 747 }
 748 EXPORT_SYMBOL(qdisc_class_hash_insert);
 749
 750 void qdisc_class_hash_remove(struct Qdisc_class_hash *clhash,
 751                              struct Qdisc_class_common *cl)
 752 {
 753         hlist_del(&cl->hnode);
 754         clhash->hashelems--;
 755 }
 756 EXPORT_SYMBOL(qdisc_class_hash_remove);
 757
 758 /* Allocate an unique handle from space managed by kernel
 759  * Possible range is [8000-FFFF]:0000 (0x8000 values)
 760  */
 761 static u32 qdisc_alloc_handle(struct net_device *dev)
 762 {
 763         int i = 0x8000;
 764         static u32 autohandle = TC_H_MAKE(0x80000000U, 0);
 765
 766         do {
 767                 autohandle += TC_H_MAKE(0x10000U, 0);
 768                 if (autohandle == TC_H_MAKE(TC_H_ROOT, 0))
 769                         autohandle = TC_H_MAKE(0x80000000U, 0);
 770                 if (!qdisc_lookup(dev, autohandle))
 771                         return autohandle;
 772                 cond_resched();
 773         } while (--i > 0);
 774
 775         return 0;
 776 }
 777
 778 void qdisc_tree_reduce_backlog(struct Qdisc *sch, int n, int len)
 779 {
 780         bool qdisc_is_offloaded = sch->flags & TCQ_F_OFFLOADED;
 781         const struct Qdisc_class_ops *cops;
 782         unsigned long cl;
 783         u32 parentid;
 784         bool notify;
 785         int drops;
 786
 787         if (n == 0 && len == 0)
 788                 return;
 789         drops = max_t(int, n, 0);
 790         rcu_read_lock();
 791         while ((parentid = sch->parent)) {
 792                 if (TC_H_MAJ(parentid) == TC_H_MAJ(TC_H_INGRESS))
 793                         break;
 794
 795                 if (sch->flags & TCQ_F_NOPARENT)
 796                         break;
 797                 /* Notify parent qdisc only if child qdisc becomes empty.
 798                  *
 799                  * If child was empty even before update then backlog
 800                  * counter is screwed and we skip notification because
 801                  * parent class is already passive.
 802                  *
 803                  * If the original child was offloaded then it is allowed
 804                  * to be seem as empty, so the parent is notified anyway.
 805                  */
 806                 notify = !sch->q.qlen && !WARN_ON_ONCE(!n &&
 807                                                        !qdisc_is_offloaded);
 808                 /* TODO: perform the search on a per txq basis */
 809                 sch = qdisc_lookup(qdisc_dev(sch), TC_H_MAJ(parentid));
 810                 if (sch == NULL) {
 811                         WARN_ON_ONCE(parentid != TC_H_ROOT);
 812                         break;
 813                 }
 814                 cops = sch->ops->cl_ops;
 815                 if (notify && cops->qlen_notify) {
 816                         cl = cops->find(sch, parentid);
 817                         cops->qlen_notify(sch, cl);
 818                 }
 819                 sch->q.qlen -= n;
 820                 sch->qstats.backlog -= len;
 821                 __qdisc_qstats_drop(sch, drops);
 822         }
 823         rcu_read_unlock();
 824 }
 825 EXPORT_SYMBOL(qdisc_tree_reduce_backlog);
 826
 827 int qdisc_offload_dump_helper(struct Qdisc *sch, enum tc_setup_type type,
 828                               void *type_data)
 829 {
 830         struct net_device *dev = qdisc_dev(sch);
 831         int err;
 832
 833         sch->flags &= ~TCQ_F_OFFLOADED;
 834         if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
 835                 return 0;
 836
 837         err = dev->netdev_ops->ndo_setup_tc(dev, type, type_data);
 838         if (err == -EOPNOTSUPP)
 839                 return 0;
 840
 841         if (!err)
 842                 sch->flags |= TCQ_F_OFFLOADED;
 843
 844         return err;
 845 }
 846 EXPORT_SYMBOL(qdisc_offload_dump_helper);
 847
 848 void qdisc_offload_graft_helper(struct net_device *dev, struct Qdisc *sch,
 849                                 struct Qdisc *new, struct Qdisc *old,
 850                                 enum tc_setup_type type, void *type_data,
 851                                 struct netlink_ext_ack *extack)
 852 {
 853         bool any_qdisc_is_offloaded;
 854         int err;
 855
 856         if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
 857                 return;
 858
 859         err = dev->netdev_ops->ndo_setup_tc(dev, type, type_data);
 860
 861         /* Don't report error if the graft is part of destroy operation. */
 862         if (!err || !new || new == &noop_qdisc)
 863                 return;
 864
 865         /* Don't report error if the parent, the old child and the new
 866          * one are not offloaded.
 867          */
 868         any_qdisc_is_offloaded = new->flags & TCQ_F_OFFLOADED;
 869         any_qdisc_is_offloaded |= sch && sch->flags & TCQ_F_OFFLOADED;
 870         any_qdisc_is_offloaded |= old && old->flags & TCQ_F_OFFLOADED;
 871
 872         if (any_qdisc_is_offloaded)
 873                 NL_SET_ERR_MSG(extack, "Offloading graft operation failed.");
 874 }
 875 EXPORT_SYMBOL(qdisc_offload_graft_helper);
 876
 877 void qdisc_offload_query_caps(struct net_device *dev,
 878                               enum tc_setup_type type,
 879                               void *caps, size_t caps_len)
 880 {
 881         const struct net_device_ops *ops = dev->netdev_ops;
 882         struct tc_query_caps_base base = {
 883                 .type = type,
 884                 .caps = caps,
 885         };
 886
 887         memset(caps, 0, caps_len);
 888
 889         if (ops->ndo_setup_tc)
 890                 ops->ndo_setup_tc(dev, TC_QUERY_CAPS, &base);
 891 }
 892 EXPORT_SYMBOL(qdisc_offload_query_caps);
 893
 894 static void qdisc_offload_graft_root(struct net_device *dev,
 895                                      struct Qdisc *new, struct Qdisc *old,
 896                                      struct netlink_ext_ack *extack)
 897 {
 898         struct tc_root_qopt_offload graft_offload = {
 899                 .command        = TC_ROOT_GRAFT,
 900                 .handle         = new ? new->handle : 0,
 901                 .ingress        = (new && new->flags & TCQ_F_INGRESS) ||
 902                                   (old && old->flags & TCQ_F_INGRESS),
 903         };
 904
 905         qdisc_offload_graft_helper(dev, NULL, new, old,
 906                                    TC_SETUP_ROOT_QDISC, &graft_offload, extack);
 907 }
 908
 909 static int tc_fill_qdisc(struct sk_buff *skb, struct Qdisc *q, u32 clid,
 910                          u32 portid, u32 seq, u16 flags, int event,
 911                          struct netlink_ext_ack *extack)
 912 {
 913         struct gnet_stats_basic_sync __percpu *cpu_bstats = NULL;
 914         struct gnet_stats_queue __percpu *cpu_qstats = NULL;
 915         struct tcmsg *tcm;
 916         struct nlmsghdr  *nlh;
 917         unsigned char *b = skb_tail_pointer(skb);
 918         struct gnet_dump d;
 919         struct qdisc_size_table *stab;
 920         u32 block_index;
 921         __u32 qlen;
 922
 923         cond_resched();
 924         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*tcm), flags);
 925         if (!nlh)
 926                 goto out_nlmsg_trim;
 927         tcm = nlmsg_data(nlh);
 928         tcm->tcm_family = AF_UNSPEC;
 929         tcm->tcm__pad1 = 0;
 930         tcm->tcm__pad2 = 0;
 931         tcm->tcm_ifindex = qdisc_dev(q)->ifindex;
 932         tcm->tcm_parent = clid;
 933         tcm->tcm_handle = q->handle;
 934         tcm->tcm_info = refcount_read(&q->refcnt);
 935         if (nla_put_string(skb, TCA_KIND, q->ops->id))
 936                 goto nla_put_failure;
 937         if (q->ops->ingress_block_get) {
 938                 block_index = q->ops->ingress_block_get(q);
 939                 if (block_index &&
 940                     nla_put_u32(skb, TCA_INGRESS_BLOCK, block_index))
 941                         goto nla_put_failure;
 942         }
 943         if (q->ops->egress_block_get) {
 944                 block_index = q->ops->egress_block_get(q);
 945                 if (block_index &&
 946                     nla_put_u32(skb, TCA_EGRESS_BLOCK, block_index))
 947                         goto nla_put_failure;
 948         }
 949         if (q->ops->dump && q->ops->dump(q, skb) < 0)
 950                 goto nla_put_failure;
 951         if (nla_put_u8(skb, TCA_HW_OFFLOAD, !!(q->flags & TCQ_F_OFFLOADED)))
 952                 goto nla_put_failure;
 953         qlen = qdisc_qlen_sum(q);
 954
 955         stab = rtnl_dereference(q->stab);
 956         if (stab && qdisc_dump_stab(skb, stab) < 0)
 957                 goto nla_put_failure;
 958
 959         if (gnet_stats_start_copy_compat(skb, TCA_STATS2, TCA_STATS, TCA_XSTATS,
 960                                          NULL, &d, TCA_PAD) < 0)
 961                 goto nla_put_failure;
 962
 963         if (q->ops->dump_stats && q->ops->dump_stats(q, &d) < 0)
 964                 goto nla_put_failure;
 965
 966         if (qdisc_is_percpu_stats(q)) {
 967                 cpu_bstats = q->cpu_bstats;
 968                 cpu_qstats = q->cpu_qstats;
 969         }
 970
 971         if (gnet_stats_copy_basic(&d, cpu_bstats, &q->bstats, true) < 0 ||
 972             gnet_stats_copy_rate_est(&d, &q->rate_est) < 0 ||
 973             gnet_stats_copy_queue(&d, cpu_qstats, &q->qstats, qlen) < 0)
 974                 goto nla_put_failure;
 975
 976         if (gnet_stats_finish_copy(&d) < 0)
 977                 goto nla_put_failure;
 978
 979         if (extack && extack->_msg &&
 980             nla_put_string(skb, TCA_EXT_WARN_MSG, extack->_msg))
 981                 goto out_nlmsg_trim;
 982
 983         nlh->nlmsg_len = skb_tail_pointer(skb) - b;
 984
 985         return skb->len;
 986
 987 out_nlmsg_trim:
 988 nla_put_failure:
 989         nlmsg_trim(skb, b);
 990         return -1;
 991 }
 992
 993 static bool tc_qdisc_dump_ignore(struct Qdisc *q, bool dump_invisible)
 994 {
 995         if (q->flags & TCQ_F_BUILTIN)
 996                 return true;
 997         if ((q->flags & TCQ_F_INVISIBLE) && !dump_invisible)
 998                 return true;
 999
1000         return false;
1001 }
1002
1003 static int qdisc_notify(struct net *net, struct sk_buff *oskb,
1004                         struct nlmsghdr *n, u32 clid,
1005                         struct Qdisc *old, struct Qdisc *new,
1006                         struct netlink_ext_ack *extack)
1007 {
1008         struct sk_buff *skb;
1009         u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
1010
1011         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
1012         if (!skb)
1013                 return -ENOBUFS;
1014
1015         if (old && !tc_qdisc_dump_ignore(old, false)) {
1016                 if (tc_fill_qdisc(skb, old, clid, portid, n->nlmsg_seq,
1017                                   0, RTM_DELQDISC, extack) < 0)
1018                         goto err_out;
1019         }
1020         if (new && !tc_qdisc_dump_ignore(new, false)) {
1021                 if (tc_fill_qdisc(skb, new, clid, portid, n->nlmsg_seq,
1022                                   old ? NLM_F_REPLACE : 0, RTM_NEWQDISC, extack) < 0)
1023                         goto err_out;
1024         }
1025
1026         if (skb->len)
1027                 return rtnetlink_send(skb, net, portid, RTNLGRP_TC,
1028                                       n->nlmsg_flags & NLM_F_ECHO);
1029
1030 err_out:
1031         kfree_skb(skb);
1032         return -EINVAL;
1033 }
1034
1035 static void notify_and_destroy(struct net *net, struct sk_buff *skb,
1036                                struct nlmsghdr *n, u32 clid,
1037                                struct Qdisc *old, struct Qdisc *new,
1038                                struct netlink_ext_ack *extack)
1039 {
1040         if (new || old)
1041                 qdisc_notify(net, skb, n, clid, old, new, extack);
1042
1043         if (old)
1044                 qdisc_put(old);
1045 }
1046
1047 static void qdisc_clear_nolock(struct Qdisc *sch)
1048 {
1049         sch->flags &= ~TCQ_F_NOLOCK;
1050         if (!(sch->flags & TCQ_F_CPUSTATS))
1051                 return;
1052
1053         free_percpu(sch->cpu_bstats);
1054         free_percpu(sch->cpu_qstats);
1055         sch->cpu_bstats = NULL;
1056         sch->cpu_qstats = NULL;
1057         sch->flags &= ~TCQ_F_CPUSTATS;
1058 }
1059
1060 /* Graft qdisc "new" to class "classid" of qdisc "parent" or
1061  * to device "dev".
1062  *
1063  * When appropriate send a netlink notification using 'skb'
1064  * and "n".
1065  *
1066  * On success, destroy old qdisc.
1067  */
1068
1069 static int qdisc_graft(struct net_device *dev, struct Qdisc *parent,
1070                        struct sk_buff *skb, struct nlmsghdr *n, u32 classid,
1071                        struct Qdisc *new, struct Qdisc *old,
1072                        struct netlink_ext_ack *extack)
1073 {
1074         struct Qdisc *q = old;
1075         struct net *net = dev_net(dev);
1076
1077         if (parent == NULL) {
1078                 unsigned int i, num_q, ingress;
1079                 struct netdev_queue *dev_queue;
1080
1081                 ingress = 0;
1082                 num_q = dev->num_tx_queues;
1083                 if ((q && q->flags & TCQ_F_INGRESS) ||
1084                     (new && new->flags & TCQ_F_INGRESS)) {
1085                         ingress = 1;
1086                         dev_queue = dev_ingress_queue(dev);
1087                         if (!dev_queue) {
1088                                 NL_SET_ERR_MSG(extack, "Device does not have an ingress queue");
1089                                 return -ENOENT;
1090                         }
1091
1092                         q = rtnl_dereference(dev_queue->qdisc_sleeping);
1093
1094                         /* This is the counterpart of that qdisc_refcount_inc_nz() call in
1095                          * __tcf_qdisc_find() for filter requests.
1096                          */
1097                         if (!qdisc_refcount_dec_if_one(q)) {
1098                                 NL_SET_ERR_MSG(extack,
1099                                                "Current ingress or clsact Qdisc has ongoing filter requests");
1100                                 return -EBUSY;
1101                         }
1102                 }
1103
1104                 if (dev->flags & IFF_UP)
1105                         dev_deactivate(dev);
1106
1107                 qdisc_offload_graft_root(dev, new, old, extack);
1108
1109                 if (new && new->ops->attach && !ingress)
1110                         goto skip;
1111
1112                 if (!ingress) {
1113                         for (i = 0; i < num_q; i++) {
1114                                 dev_queue = netdev_get_tx_queue(dev, i);
1115                                 old = dev_graft_qdisc(dev_queue, new);
1116
1117                                 if (new && i > 0)
1118                                         qdisc_refcount_inc(new);
1119                                 qdisc_put(old);
1120                         }
1121                 } else {
1122                         old = dev_graft_qdisc(dev_queue, NULL);
1123
1124                         /* {ingress,clsact}_destroy() @old before grafting @new to avoid
1125                          * unprotected concurrent accesses to net_device::miniq_{in,e}gress
1126                          * pointer(s) in mini_qdisc_pair_swap().
1127                          */
1128                         qdisc_notify(net, skb, n, classid, old, new, extack);
1129                         qdisc_destroy(old);
1130
1131                         dev_graft_qdisc(dev_queue, new);
1132                 }
1133
1134 skip:
1135                 if (!ingress) {
1136                         old = rtnl_dereference(dev->qdisc);
1137                         if (new && !new->ops->attach)
1138                                 qdisc_refcount_inc(new);
1139                         rcu_assign_pointer(dev->qdisc, new ? : &noop_qdisc);
1140
1141                         notify_and_destroy(net, skb, n, classid, old, new, extack);
1142
1143                         if (new && new->ops->attach)
1144                                 new->ops->attach(new);
1145                 }
1146
1147                 if (dev->flags & IFF_UP)
1148                         dev_activate(dev);
1149         } else {
1150                 const struct Qdisc_class_ops *cops = parent->ops->cl_ops;
1151                 unsigned long cl;
1152                 int err;
1153
1154                 /* Only support running class lockless if parent is lockless */
1155                 if (new && (new->flags & TCQ_F_NOLOCK) && !(parent->flags & TCQ_F_NOLOCK))
1156                         qdisc_clear_nolock(new);
1157
1158                 if (!cops || !cops->graft)
1159                         return -EOPNOTSUPP;
1160
1161                 cl = cops->find(parent, classid);
1162                 if (!cl) {
1163                         NL_SET_ERR_MSG(extack, "Specified class not found");
1164                         return -ENOENT;
1165                 }
1166
1167                 if (new && new->ops == &noqueue_qdisc_ops) {
1168                         NL_SET_ERR_MSG(extack, "Cannot assign noqueue to a class");
1169                         return -EINVAL;
1170                 }
1171
1172                 err = cops->graft(parent, cl, new, &old, extack);
1173                 if (err)
1174                         return err;
1175                 notify_and_destroy(net, skb, n, classid, old, new, extack);
1176         }
1177         return 0;
1178 }
1179
1180 static int qdisc_block_indexes_set(struct Qdisc *sch, struct nlattr **tca,
1181                                    struct netlink_ext_ack *extack)
1182 {
1183         u32 block_index;
1184
1185         if (tca[TCA_INGRESS_BLOCK]) {
1186                 block_index = nla_get_u32(tca[TCA_INGRESS_BLOCK]);
1187
1188                 if (!block_index) {
1189                         NL_SET_ERR_MSG(extack, "Ingress block index cannot be 0");
1190                         return -EINVAL;
1191                 }
1192                 if (!sch->ops->ingress_block_set) {
1193                         NL_SET_ERR_MSG(extack, "Ingress block sharing is not supported");
1194                         return -EOPNOTSUPP;
1195                 }
1196                 sch->ops->ingress_block_set(sch, block_index);
1197         }
1198         if (tca[TCA_EGRESS_BLOCK]) {
1199                 block_index = nla_get_u32(tca[TCA_EGRESS_BLOCK]);
1200
1201                 if (!block_index) {
1202                         NL_SET_ERR_MSG(extack, "Egress block index cannot be 0");
1203                         return -EINVAL;
1204                 }
1205                 if (!sch->ops->egress_block_set) {
1206                         NL_SET_ERR_MSG(extack, "Egress block sharing is not supported");
1207                         return -EOPNOTSUPP;
1208                 }
1209                 sch->ops->egress_block_set(sch, block_index);
1210         }
1211         return 0;
1212 }
1213
1214 /*
1215    Allocate and initialize new qdisc.
1216
1217    Parameters are passed via opt.
1218  */
1219
1220 static struct Qdisc *qdisc_create(struct net_device *dev,
1221                                   struct netdev_queue *dev_queue,
1222                                   u32 parent, u32 handle,
1223                                   struct nlattr **tca, int *errp,
1224                                   struct netlink_ext_ack *extack)
1225 {
1226         int err;
1227         struct nlattr *kind = tca[TCA_KIND];
1228         struct Qdisc *sch;
1229         struct Qdisc_ops *ops;
1230         struct qdisc_size_table *stab;
1231
1232         ops = qdisc_lookup_ops(kind);
1233 #ifdef CONFIG_MODULES
1234         if (ops == NULL && kind != NULL) {
1235                 char name[IFNAMSIZ];
1236                 if (nla_strscpy(name, kind, IFNAMSIZ) >= 0) {
1237                         /* We dropped the RTNL semaphore in order to
1238                          * perform the module load.  So, even if we
1239                          * succeeded in loading the module we have to
1240                          * tell the caller to replay the request.  We
1241                          * indicate this using -EAGAIN.
1242                          * We replay the request because the device may
1243                          * go away in the mean time.
1244                          */
1245                         rtnl_unlock();
1246                         request_module("sch_%s", name);
1247                         rtnl_lock();
1248                         ops = qdisc_lookup_ops(kind);
1249                         if (ops != NULL) {
1250                                 /* We will try again qdisc_lookup_ops,
1251                                  * so don't keep a reference.
1252                                  */
1253                                 module_put(ops->owner);
1254                                 err = -EAGAIN;
1255                                 goto err_out;
1256                         }
1257                 }
1258         }
1259 #endif
1260
1261         err = -ENOENT;
1262         if (!ops) {
1263                 NL_SET_ERR_MSG(extack, "Specified qdisc kind is unknown");
1264                 goto err_out;
1265         }
1266
1267         sch = qdisc_alloc(dev_queue, ops, extack);
1268         if (IS_ERR(sch)) {
1269                 err = PTR_ERR(sch);
1270                 goto err_out2;
1271         }
1272
1273         sch->parent = parent;
1274
1275         if (handle == TC_H_INGRESS) {
1276                 if (!(sch->flags & TCQ_F_INGRESS)) {
1277                         NL_SET_ERR_MSG(extack,
1278                                        "Specified parent ID is reserved for ingress and clsact Qdiscs");
1279                         err = -EINVAL;
1280                         goto err_out3;
1281                 }
1282                 handle = TC_H_MAKE(TC_H_INGRESS, 0);
1283         } else {
1284                 if (handle == 0) {
1285                         handle = qdisc_alloc_handle(dev);
1286                         if (handle == 0) {
1287                                 NL_SET_ERR_MSG(extack, "Maximum number of qdisc handles was exceeded");
1288                                 err = -ENOSPC;
1289                                 goto err_out3;
1290                         }
1291                 }
1292                 if (!netif_is_multiqueue(dev))
1293                         sch->flags |= TCQ_F_ONETXQUEUE;
1294         }
1295
1296         sch->handle = handle;
1297
1298         /* This exist to keep backward compatible with a userspace
1299          * loophole, what allowed userspace to get IFF_NO_QUEUE
1300          * facility on older kernels by setting tx_queue_len=0 (prior
1301          * to qdisc init), and then forgot to reinit tx_queue_len
1302          * before again attaching a qdisc.
1303          */
1304         if ((dev->priv_flags & IFF_NO_QUEUE) && (dev->tx_queue_len == 0)) {
1305                 dev->tx_queue_len = DEFAULT_TX_QUEUE_LEN;
1306                 netdev_info(dev, "Caught tx_queue_len zero misconfig\n");
1307         }
1308
1309         err = qdisc_block_indexes_set(sch, tca, extack);
1310         if (err)
1311                 goto err_out3;
1312
1313         if (ops->init) {
1314                 err = ops->init(sch, tca[TCA_OPTIONS], extack);
1315                 if (err != 0)
1316                         goto err_out5;
1317         }
1318
1319         if (tca[TCA_STAB]) {
1320                 stab = qdisc_get_stab(tca[TCA_STAB], extack);
1321                 if (IS_ERR(stab)) {
1322                         err = PTR_ERR(stab);
1323                         goto err_out4;
1324                 }
1325                 rcu_assign_pointer(sch->stab, stab);
1326         }
1327         if (tca[TCA_RATE]) {
1328                 err = -EOPNOTSUPP;
1329                 if (sch->flags & TCQ_F_MQROOT) {
1330                         NL_SET_ERR_MSG(extack, "Cannot attach rate estimator to a multi-queue root qdisc");
1331                         goto err_out4;
1332                 }
1333
1334                 err = gen_new_estimator(&sch->bstats,
1335                                         sch->cpu_bstats,
1336                                         &sch->rate_est,
1337                                         NULL,
1338                                         true,
1339                                         tca[TCA_RATE]);
1340                 if (err) {
1341                         NL_SET_ERR_MSG(extack, "Failed to generate new estimator");
1342                         goto err_out4;
1343                 }
1344         }
1345
1346         qdisc_hash_add(sch, false);
1347         trace_qdisc_create(ops, dev, parent);
1348
1349         return sch;
1350
1351 err_out5:
1352         /* ops->init() failed, we call ->destroy() like qdisc_create_dflt() */
1353         if (ops->destroy)
1354                 ops->destroy(sch);
1355 err_out3:
1356         netdev_put(dev, &sch->dev_tracker);
1357         qdisc_free(sch);
1358 err_out2:
1359         module_put(ops->owner);
1360 err_out:
1361         *errp = err;
1362         return NULL;
1363
1364 err_out4:
1365         /*
1366          * Any broken qdiscs that would require a ops->reset() here?
1367          * The qdisc was never in action so it shouldn't be necessary.
1368          */
1369         qdisc_put_stab(rtnl_dereference(sch->stab));
1370         if (ops->destroy)
1371                 ops->destroy(sch);
1372         goto err_out3;
1373 }
1374
1375 static int qdisc_change(struct Qdisc *sch, struct nlattr **tca,
1376                         struct netlink_ext_ack *extack)
1377 {
1378         struct qdisc_size_table *ostab, *stab = NULL;
1379         int err = 0;
1380
1381         if (tca[TCA_OPTIONS]) {
1382                 if (!sch->ops->change) {
1383                         NL_SET_ERR_MSG(extack, "Change operation not supported by specified qdisc");
1384                         return -EINVAL;
1385                 }
1386                 if (tca[TCA_INGRESS_BLOCK] || tca[TCA_EGRESS_BLOCK]) {
1387                         NL_SET_ERR_MSG(extack, "Change of blocks is not supported");
1388                         return -EOPNOTSUPP;
1389                 }
1390                 err = sch->ops->change(sch, tca[TCA_OPTIONS], extack);
1391                 if (err)
1392                         return err;
1393         }
1394
1395         if (tca[TCA_STAB]) {
1396                 stab = qdisc_get_stab(tca[TCA_STAB], extack);
1397                 if (IS_ERR(stab))
1398                         return PTR_ERR(stab);
1399         }
1400
1401         ostab = rtnl_dereference(sch->stab);
1402         rcu_assign_pointer(sch->stab, stab);
1403         qdisc_put_stab(ostab);
1404
1405         if (tca[TCA_RATE]) {
1406                 /* NB: ignores errors from replace_estimator
1407                    because change can't be undone. */
1408                 if (sch->flags & TCQ_F_MQROOT)
1409                         goto out;
1410                 gen_replace_estimator(&sch->bstats,
1411                                       sch->cpu_bstats,
1412                                       &sch->rate_est,
1413                                       NULL,
1414                                       true,
1415                                       tca[TCA_RATE]);
1416         }
1417 out:
1418         return 0;
1419 }
1420
1421 struct check_loop_arg {
1422         struct qdisc_walker     w;
1423         struct Qdisc            *p;
1424         int                     depth;
1425 };
1426
1427 static int check_loop_fn(struct Qdisc *q, unsigned long cl,
1428                          struct qdisc_walker *w);
1429
1430 static int check_loop(struct Qdisc *q, struct Qdisc *p, int depth)
1431 {
1432         struct check_loop_arg   arg;
1433
1434         if (q->ops->cl_ops == NULL)
1435                 return 0;
1436
1437         arg.w.stop = arg.w.skip = arg.w.count = 0;
1438         arg.w.fn = check_loop_fn;
1439         arg.depth = depth;
1440         arg.p = p;
1441         q->ops->cl_ops->walk(q, &arg.w);
1442         return arg.w.stop ? -ELOOP : 0;
1443 }
1444
1445 static int
1446 check_loop_fn(struct Qdisc *q, unsigned long cl, struct qdisc_walker *w)
1447 {
1448         struct Qdisc *leaf;
1449         const struct Qdisc_class_ops *cops = q->ops->cl_ops;
1450         struct check_loop_arg *arg = (struct check_loop_arg *)w;
1451
1452         leaf = cops->leaf(q, cl);
1453         if (leaf) {
1454                 if (leaf == arg->p || arg->depth > 7)
1455                         return -ELOOP;
1456                 return check_loop(leaf, arg->p, arg->depth + 1);
1457         }
1458         return 0;
1459 }
1460
1461 const struct nla_policy rtm_tca_policy[TCA_MAX + 1] = {
1462         [TCA_KIND]              = { .type = NLA_STRING },
1463         [TCA_RATE]              = { .type = NLA_BINARY,
1464                                     .len = sizeof(struct tc_estimator) },
1465         [TCA_STAB]              = { .type = NLA_NESTED },
1466         [TCA_DUMP_INVISIBLE]    = { .type = NLA_FLAG },
1467         [TCA_CHAIN]             = { .type = NLA_U32 },
1468         [TCA_INGRESS_BLOCK]     = { .type = NLA_U32 },
1469         [TCA_EGRESS_BLOCK]      = { .type = NLA_U32 },
1470 };
1471
1472 /*
1473  * Delete/get qdisc.
1474  */
1475
1476 static int tc_get_qdisc(struct sk_buff *skb, struct nlmsghdr *n,
1477                         struct netlink_ext_ack *extack)
1478 {
1479         struct net *net = sock_net(skb->sk);
1480         struct tcmsg *tcm = nlmsg_data(n);
1481         struct nlattr *tca[TCA_MAX + 1];
1482         struct net_device *dev;
1483         u32 clid;
1484         struct Qdisc *q = NULL;
1485         struct Qdisc *p = NULL;
1486         int err;
1487
1488         err = nlmsg_parse_deprecated(n, sizeof(*tcm), tca, TCA_MAX,
1489                                      rtm_tca_policy, extack);
1490         if (err < 0)
1491                 return err;
1492
1493         dev = __dev_get_by_index(net, tcm->tcm_ifindex);
1494         if (!dev)
1495                 return -ENODEV;
1496
1497         clid = tcm->tcm_parent;
1498         if (clid) {
1499                 if (clid != TC_H_ROOT) {
1500                         if (TC_H_MAJ(clid) != TC_H_MAJ(TC_H_INGRESS)) {
1501                                 p = qdisc_lookup(dev, TC_H_MAJ(clid));
1502                                 if (!p) {
1503                                         NL_SET_ERR_MSG(extack, "Failed to find qdisc with specified classid");
1504                                         return -ENOENT;
1505                                 }
1506                                 q = qdisc_leaf(p, clid);
1507                         } else if (dev_ingress_queue(dev)) {
1508                                 q = rtnl_dereference(dev_ingress_queue(dev)->qdisc_sleeping);
1509                         }
1510                 } else {
1511                         q = rtnl_dereference(dev->qdisc);
1512                 }
1513                 if (!q) {
1514                         NL_SET_ERR_MSG(extack, "Cannot find specified qdisc on specified device");
1515                         return -ENOENT;
1516                 }
1517
1518                 if (tcm->tcm_handle && q->handle != tcm->tcm_handle) {
1519                         NL_SET_ERR_MSG(extack, "Invalid handle");
1520                         return -EINVAL;
1521                 }
1522         } else {
1523                 q = qdisc_lookup(dev, tcm->tcm_handle);
1524                 if (!q) {
1525                         NL_SET_ERR_MSG(extack, "Failed to find qdisc with specified handle");
1526                         return -ENOENT;
1527                 }
1528         }
1529
1530         if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], q->ops->id)) {
1531                 NL_SET_ERR_MSG(extack, "Invalid qdisc name");
1532                 return -EINVAL;
1533         }
1534
1535         if (n->nlmsg_type == RTM_DELQDISC) {
1536                 if (!clid) {
1537                         NL_SET_ERR_MSG(extack, "Classid cannot be zero");
1538                         return -EINVAL;
1539                 }
1540                 if (q->handle == 0) {
1541                         NL_SET_ERR_MSG(extack, "Cannot delete qdisc with handle of zero");
1542                         return -ENOENT;
1543                 }
1544                 err = qdisc_graft(dev, p, skb, n, clid, NULL, q, extack);
1545                 if (err != 0)
1546                         return err;
1547         } else {
1548                 qdisc_notify(net, skb, n, clid, NULL, q, NULL);
1549         }
1550         return 0;
1551 }
1552
1553 /*
1554  * Create/change qdisc.
1555  */
1556
1557 static int tc_modify_qdisc(struct sk_buff *skb, struct nlmsghdr *n,
1558                            struct netlink_ext_ack *extack)
1559 {
1560         struct net *net = sock_net(skb->sk);
1561         struct tcmsg *tcm;
1562         struct nlattr *tca[TCA_MAX + 1];
1563         struct net_device *dev;
1564         u32 clid;
1565         struct Qdisc *q, *p;
1566         int err;
1567
1568 replay:
1569         /* Reinit, just in case something touches this. */
1570         err = nlmsg_parse_deprecated(n, sizeof(*tcm), tca, TCA_MAX,
1571                                      rtm_tca_policy, extack);
1572         if (err < 0)
1573                 return err;
1574
1575         tcm = nlmsg_data(n);
1576         clid = tcm->tcm_parent;
1577         q = p = NULL;
1578
1579         dev = __dev_get_by_index(net, tcm->tcm_ifindex);
1580         if (!dev)
1581                 return -ENODEV;
1582
1583
1584         if (clid) {
1585                 if (clid != TC_H_ROOT) {
1586                         if (clid != TC_H_INGRESS) {
1587                                 p = qdisc_lookup(dev, TC_H_MAJ(clid));
1588                                 if (!p) {
1589                                         NL_SET_ERR_MSG(extack, "Failed to find specified qdisc");
1590                                         return -ENOENT;
1591                                 }
1592                                 q = qdisc_leaf(p, clid);
1593                         } else if (dev_ingress_queue_create(dev)) {
1594                                 q = rtnl_dereference(dev_ingress_queue(dev)->qdisc_sleeping);
1595                         }
1596                 } else {
1597                         q = rtnl_dereference(dev->qdisc);
1598                 }
1599
1600                 /* It may be default qdisc, ignore it */
1601                 if (q && q->handle == 0)
1602                         q = NULL;
1603
1604                 if (!q || !tcm->tcm_handle || q->handle != tcm->tcm_handle) {
1605                         if (tcm->tcm_handle) {
1606                                 if (q && !(n->nlmsg_flags & NLM_F_REPLACE)) {
1607                                         NL_SET_ERR_MSG(extack, "NLM_F_REPLACE needed to override");
1608                                         return -EEXIST;
1609                                 }
1610                                 if (TC_H_MIN(tcm->tcm_handle)) {
1611                                         NL_SET_ERR_MSG(extack, "Invalid minor handle");
1612                                         return -EINVAL;
1613                                 }
1614                                 q = qdisc_lookup(dev, tcm->tcm_handle);
1615                                 if (!q)
1616                                         goto create_n_graft;
1617                                 if (n->nlmsg_flags & NLM_F_EXCL) {
1618                                         NL_SET_ERR_MSG(extack, "Exclusivity flag on, cannot override");
1619                                         return -EEXIST;
1620                                 }
1621                                 if (tca[TCA_KIND] &&
1622                                     nla_strcmp(tca[TCA_KIND], q->ops->id)) {
1623                                         NL_SET_ERR_MSG(extack, "Invalid qdisc name");
1624                                         return -EINVAL;
1625                                 }
1626                                 if (q->flags & TCQ_F_INGRESS) {
1627                                         NL_SET_ERR_MSG(extack,
1628                                                        "Cannot regraft ingress or clsact Qdiscs");
1629                                         return -EINVAL;
1630                                 }
1631                                 if (q == p ||
1632                                     (p && check_loop(q, p, 0))) {
1633                                         NL_SET_ERR_MSG(extack, "Qdisc parent/child loop detected");
1634                                         return -ELOOP;
1635                                 }
1636                                 if (clid == TC_H_INGRESS) {
1637                                         NL_SET_ERR_MSG(extack, "Ingress cannot graft directly");
1638                                         return -EINVAL;
1639                                 }
1640                                 qdisc_refcount_inc(q);
1641                                 goto graft;
1642                         } else {
1643                                 if (!q)
1644                                         goto create_n_graft;
1645
1646                                 /* This magic test requires explanation.
1647                                  *
1648                                  *   We know, that some child q is already
1649                                  *   attached to this parent and have choice:
1650                                  *   either to change it or to create/graft new one.
1651                                  *
1652                                  *   1. We are allowed to create/graft only
1653                                  *   if CREATE and REPLACE flags are set.
1654                                  *
1655                                  *   2. If EXCL is set, requestor wanted to say,
1656                                  *   that qdisc tcm_handle is not expected
1657                                  *   to exist, so that we choose create/graft too.
1658                                  *
1659                                  *   3. The last case is when no flags are set.
1660                                  *   Alas, it is sort of hole in API, we
1661                                  *   cannot decide what to do unambiguously.
1662                                  *   For now we select create/graft, if
1663                                  *   user gave KIND, which does not match existing.
1664                                  */
1665                                 if ((n->nlmsg_flags & NLM_F_CREATE) &&
1666                                     (n->nlmsg_flags & NLM_F_REPLACE) &&
1667                                     ((n->nlmsg_flags & NLM_F_EXCL) ||
1668                                      (tca[TCA_KIND] &&
1669                                       nla_strcmp(tca[TCA_KIND], q->ops->id))))
1670                                         goto create_n_graft;
1671                         }
1672                 }
1673         } else {
1674                 if (!tcm->tcm_handle) {
1675                         NL_SET_ERR_MSG(extack, "Handle cannot be zero");
1676                         return -EINVAL;
1677                 }
1678                 q = qdisc_lookup(dev, tcm->tcm_handle);
1679         }
1680
1681         /* Change qdisc parameters */
1682         if (!q) {
1683                 NL_SET_ERR_MSG(extack, "Specified qdisc not found");
1684                 return -ENOENT;
1685         }
1686         if (n->nlmsg_flags & NLM_F_EXCL) {
1687                 NL_SET_ERR_MSG(extack, "Exclusivity flag on, cannot modify");
1688                 return -EEXIST;
1689         }
1690         if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], q->ops->id)) {
1691                 NL_SET_ERR_MSG(extack, "Invalid qdisc name");
1692                 return -EINVAL;
1693         }
1694         err = qdisc_change(q, tca, extack);
1695         if (err == 0)
1696                 qdisc_notify(net, skb, n, clid, NULL, q, extack);
1697         return err;
1698
1699 create_n_graft:
1700         if (!(n->nlmsg_flags & NLM_F_CREATE)) {
1701                 NL_SET_ERR_MSG(extack, "Qdisc not found. To create specify NLM_F_CREATE flag");
1702                 return -ENOENT;
1703         }
1704         if (clid == TC_H_INGRESS) {
1705                 if (dev_ingress_queue(dev)) {
1706                         q = qdisc_create(dev, dev_ingress_queue(dev),
1707                                          tcm->tcm_parent, tcm->tcm_parent,
1708                                          tca, &err, extack);
1709                 } else {
1710                         NL_SET_ERR_MSG(extack, "Cannot find ingress queue for specified device");
1711                         err = -ENOENT;
1712                 }
1713         } else {
1714                 struct netdev_queue *dev_queue;
1715
1716                 if (p && p->ops->cl_ops && p->ops->cl_ops->select_queue)
1717                         dev_queue = p->ops->cl_ops->select_queue(p, tcm);
1718                 else if (p)
1719                         dev_queue = p->dev_queue;
1720                 else
1721                         dev_queue = netdev_get_tx_queue(dev, 0);
1722
1723                 q = qdisc_create(dev, dev_queue,
1724                                  tcm->tcm_parent, tcm->tcm_handle,
1725                                  tca, &err, extack);
1726         }
1727         if (q == NULL) {
1728                 if (err == -EAGAIN)
1729                         goto replay;
1730                 return err;
1731         }
1732
1733 graft:
1734         err = qdisc_graft(dev, p, skb, n, clid, q, NULL, extack);
1735         if (err) {
1736                 if (q)
1737                         qdisc_put(q);
1738                 return err;
1739         }
1740
1741         return 0;
1742 }
1743
1744 static int tc_dump_qdisc_root(struct Qdisc *root, struct sk_buff *skb,
1745                               struct netlink_callback *cb,
1746                               int *q_idx_p, int s_q_idx, bool recur,
1747                               bool dump_invisible)
1748 {
1749         int ret = 0, q_idx = *q_idx_p;
1750         struct Qdisc *q;
1751         int b;
1752
1753         if (!root)
1754                 return 0;
1755
1756         q = root;
1757         if (q_idx < s_q_idx) {
1758                 q_idx++;
1759         } else {
1760                 if (!tc_qdisc_dump_ignore(q, dump_invisible) &&
1761                     tc_fill_qdisc(skb, q, q->parent, NETLINK_CB(cb->skb).portid,
1762                                   cb->nlh->nlmsg_seq, NLM_F_MULTI,
1763                                   RTM_NEWQDISC, NULL) <= 0)
1764                         goto done;
1765                 q_idx++;
1766         }
1767
1768         /* If dumping singletons, there is no qdisc_dev(root) and the singleton
1769          * itself has already been dumped.
1770          *
1771          * If we've already dumped the top-level (ingress) qdisc above and the global
1772          * qdisc hashtable, we don't want to hit it again
1773          */
1774         if (!qdisc_dev(root) || !recur)
1775                 goto out;
1776
1777         hash_for_each(qdisc_dev(root)->qdisc_hash, b, q, hash) {
1778                 if (q_idx < s_q_idx) {
1779                         q_idx++;
1780                         continue;
1781                 }
1782                 if (!tc_qdisc_dump_ignore(q, dump_invisible) &&
1783                     tc_fill_qdisc(skb, q, q->parent, NETLINK_CB(cb->skb).portid,
1784                                   cb->nlh->nlmsg_seq, NLM_F_MULTI,
1785                                   RTM_NEWQDISC, NULL) <= 0)
1786                         goto done;
1787                 q_idx++;
1788         }
1789
1790 out:
1791         *q_idx_p = q_idx;
1792         return ret;
1793 done:
1794         ret = -1;
1795         goto out;
1796 }
1797
1798 static int tc_dump_qdisc(struct sk_buff *skb, struct netlink_callback *cb)
1799 {
1800         struct net *net = sock_net(skb->sk);
1801         int idx, q_idx;
1802         int s_idx, s_q_idx;
1803         struct net_device *dev;
1804         const struct nlmsghdr *nlh = cb->nlh;
1805         struct nlattr *tca[TCA_MAX + 1];
1806         int err;
1807
1808         s_idx = cb->args[0];
1809         s_q_idx = q_idx = cb->args[1];
1810
1811         idx = 0;
1812         ASSERT_RTNL();
1813
1814         err = nlmsg_parse_deprecated(nlh, sizeof(struct tcmsg), tca, TCA_MAX,
1815                                      rtm_tca_policy, cb->extack);
1816         if (err < 0)
1817                 return err;
1818
1819         for_each_netdev(net, dev) {
1820                 struct netdev_queue *dev_queue;
1821
1822                 if (idx < s_idx)
1823                         goto cont;
1824                 if (idx > s_idx)
1825                         s_q_idx = 0;
1826                 q_idx = 0;
1827
1828                 if (tc_dump_qdisc_root(rtnl_dereference(dev->qdisc),
1829                                        skb, cb, &q_idx, s_q_idx,
1830                                        true, tca[TCA_DUMP_INVISIBLE]) < 0)
1831                         goto done;
1832
1833                 dev_queue = dev_ingress_queue(dev);
1834                 if (dev_queue &&
1835                     tc_dump_qdisc_root(rtnl_dereference(dev_queue->qdisc_sleeping),
1836                                        skb, cb, &q_idx, s_q_idx, false,
1837                                        tca[TCA_DUMP_INVISIBLE]) < 0)
1838                         goto done;
1839
1840 cont:
1841                 idx++;
1842         }
1843
1844 done:
1845         cb->args[0] = idx;
1846         cb->args[1] = q_idx;
1847
1848         return skb->len;
1849 }
1850
1851
1852
1853 /************************************************
1854  *      Traffic classes manipulation.           *
1855  ************************************************/
1856
1857 static int tc_fill_tclass(struct sk_buff *skb, struct Qdisc *q,
1858                           unsigned long cl, u32 portid, u32 seq, u16 flags,
1859                           int event, struct netlink_ext_ack *extack)
1860 {
1861         struct tcmsg *tcm;
1862         struct nlmsghdr  *nlh;
1863         unsigned char *b = skb_tail_pointer(skb);
1864         struct gnet_dump d;
1865         const struct Qdisc_class_ops *cl_ops = q->ops->cl_ops;
1866
1867         cond_resched();
1868         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*tcm), flags);
1869         if (!nlh)
1870                 goto out_nlmsg_trim;
1871         tcm = nlmsg_data(nlh);
1872         tcm->tcm_family = AF_UNSPEC;
1873         tcm->tcm__pad1 = 0;
1874         tcm->tcm__pad2 = 0;
1875         tcm->tcm_ifindex = qdisc_dev(q)->ifindex;
1876         tcm->tcm_parent = q->handle;
1877         tcm->tcm_handle = q->handle;
1878         tcm->tcm_info = 0;
1879         if (nla_put_string(skb, TCA_KIND, q->ops->id))
1880                 goto nla_put_failure;
1881         if (cl_ops->dump && cl_ops->dump(q, cl, skb, tcm) < 0)
1882                 goto nla_put_failure;
1883
1884         if (gnet_stats_start_copy_compat(skb, TCA_STATS2, TCA_STATS, TCA_XSTATS,
1885                                          NULL, &d, TCA_PAD) < 0)
1886                 goto nla_put_failure;
1887
1888         if (cl_ops->dump_stats && cl_ops->dump_stats(q, cl, &d) < 0)
1889                 goto nla_put_failure;
1890
1891         if (gnet_stats_finish_copy(&d) < 0)
1892                 goto nla_put_failure;
1893
1894         if (extack && extack->_msg &&
1895             nla_put_string(skb, TCA_EXT_WARN_MSG, extack->_msg))
1896                 goto out_nlmsg_trim;
1897
1898         nlh->nlmsg_len = skb_tail_pointer(skb) - b;
1899
1900         return skb->len;
1901
1902 out_nlmsg_trim:
1903 nla_put_failure:
1904         nlmsg_trim(skb, b);
1905         return -1;
1906 }
1907
1908 static int tclass_notify(struct net *net, struct sk_buff *oskb,
1909                          struct nlmsghdr *n, struct Qdisc *q,
1910                          unsigned long cl, int event, struct netlink_ext_ack *extack)
1911 {
1912         struct sk_buff *skb;
1913         u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
1914
1915         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
1916         if (!skb)
1917                 return -ENOBUFS;
1918
1919         if (tc_fill_tclass(skb, q, cl, portid, n->nlmsg_seq, 0, event, extack) < 0) {
1920                 kfree_skb(skb);
1921                 return -EINVAL;
1922         }
1923
1924         return rtnetlink_send(skb, net, portid, RTNLGRP_TC,
1925                               n->nlmsg_flags & NLM_F_ECHO);
1926 }
1927
1928 static int tclass_del_notify(struct net *net,
1929                              const struct Qdisc_class_ops *cops,
1930                              struct sk_buff *oskb, struct nlmsghdr *n,
1931                              struct Qdisc *q, unsigned long cl,
1932                              struct netlink_ext_ack *extack)
1933 {
1934         u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
1935         struct sk_buff *skb;
1936         int err = 0;
1937
1938         if (!cops->delete)
1939                 return -EOPNOTSUPP;
1940
1941         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
1942         if (!skb)
1943                 return -ENOBUFS;
1944
1945         if (tc_fill_tclass(skb, q, cl, portid, n->nlmsg_seq, 0,
1946                            RTM_DELTCLASS, extack) < 0) {
1947                 kfree_skb(skb);
1948                 return -EINVAL;
1949         }
1950
1951         err = cops->delete(q, cl, extack);
1952         if (err) {
1953                 kfree_skb(skb);
1954                 return err;
1955         }
1956
1957         err = rtnetlink_send(skb, net, portid, RTNLGRP_TC,
1958                              n->nlmsg_flags & NLM_F_ECHO);
1959         return err;
1960 }
1961
1962 #ifdef CONFIG_NET_CLS
1963
1964 struct tcf_bind_args {
1965         struct tcf_walker w;
1966         unsigned long base;
1967         unsigned long cl;
1968         u32 classid;
1969 };
1970
1971 static int tcf_node_bind(struct tcf_proto *tp, void *n, struct tcf_walker *arg)
1972 {
1973         struct tcf_bind_args *a = (void *)arg;
1974
1975         if (n && tp->ops->bind_class) {
1976                 struct Qdisc *q = tcf_block_q(tp->chain->block);
1977
1978                 sch_tree_lock(q);
1979                 tp->ops->bind_class(n, a->classid, a->cl, q, a->base);
1980                 sch_tree_unlock(q);
1981         }
1982         return 0;
1983 }
1984
1985 struct tc_bind_class_args {
1986         struct qdisc_walker w;
1987         unsigned long new_cl;
1988         u32 portid;
1989         u32 clid;
1990 };
1991
1992 static int tc_bind_class_walker(struct Qdisc *q, unsigned long cl,
1993                                 struct qdisc_walker *w)
1994 {
1995         struct tc_bind_class_args *a = (struct tc_bind_class_args *)w;
1996         const struct Qdisc_class_ops *cops = q->ops->cl_ops;
1997         struct tcf_block *block;
1998         struct tcf_chain *chain;
1999
2000         block = cops->tcf_block(q, cl, NULL);
2001         if (!block)
2002                 return 0;
2003         for (chain = tcf_get_next_chain(block, NULL);
2004              chain;
2005              chain = tcf_get_next_chain(block, chain)) {
2006                 struct tcf_proto *tp;
2007
2008                 for (tp = tcf_get_next_proto(chain, NULL);
2009                      tp; tp = tcf_get_next_proto(chain, tp)) {
2010                         struct tcf_bind_args arg = {};
2011
2012                         arg.w.fn = tcf_node_bind;
2013                         arg.classid = a->clid;
2014                         arg.base = cl;
2015                         arg.cl = a->new_cl;
2016                         tp->ops->walk(tp, &arg.w, true);
2017                 }
2018         }
2019
2020         return 0;
2021 }
2022
2023 static void tc_bind_tclass(struct Qdisc *q, u32 portid, u32 clid,
2024                            unsigned long new_cl)
2025 {
2026         const struct Qdisc_class_ops *cops = q->ops->cl_ops;
2027         struct tc_bind_class_args args = {};
2028
2029         if (!cops->tcf_block)
2030                 return;
2031         args.portid = portid;
2032         args.clid = clid;
2033         args.new_cl = new_cl;
2034         args.w.fn = tc_bind_class_walker;
2035         q->ops->cl_ops->walk(q, &args.w);
2036 }
2037
2038 #else
2039
2040 static void tc_bind_tclass(struct Qdisc *q, u32 portid, u32 clid,
2041                            unsigned long new_cl)
2042 {
2043 }
2044
2045 #endif
2046
2047 static int tc_ctl_tclass(struct sk_buff *skb, struct nlmsghdr *n,
2048                          struct netlink_ext_ack *extack)
2049 {
2050         struct net *net = sock_net(skb->sk);
2051         struct tcmsg *tcm = nlmsg_data(n);
2052         struct nlattr *tca[TCA_MAX + 1];
2053         struct net_device *dev;
2054         struct Qdisc *q = NULL;
2055         const struct Qdisc_class_ops *cops;
2056         unsigned long cl = 0;
2057         unsigned long new_cl;
2058         u32 portid;
2059         u32 clid;
2060         u32 qid;
2061         int err;
2062
2063         err = nlmsg_parse_deprecated(n, sizeof(*tcm), tca, TCA_MAX,
2064                                      rtm_tca_policy, extack);
2065         if (err < 0)
2066                 return err;
2067
2068         dev = __dev_get_by_index(net, tcm->tcm_ifindex);
2069         if (!dev)
2070                 return -ENODEV;
2071
2072         /*
2073            parent == TC_H_UNSPEC - unspecified parent.
2074            parent == TC_H_ROOT   - class is root, which has no parent.
2075            parent == X:0         - parent is root class.
2076            parent == X:Y         - parent is a node in hierarchy.
2077            parent == 0:Y         - parent is X:Y, where X:0 is qdisc.
2078
2079            handle == 0:0         - generate handle from kernel pool.
2080            handle == 0:Y         - class is X:Y, where X:0 is qdisc.
2081            handle == X:Y         - clear.
2082            handle == X:0         - root class.
2083          */
2084
2085         /* Step 1. Determine qdisc handle X:0 */
2086
2087         portid = tcm->tcm_parent;
2088         clid = tcm->tcm_handle;
2089         qid = TC_H_MAJ(clid);
2090
2091         if (portid != TC_H_ROOT) {
2092                 u32 qid1 = TC_H_MAJ(portid);
2093
2094                 if (qid && qid1) {
2095                         /* If both majors are known, they must be identical. */
2096                         if (qid != qid1)
2097                                 return -EINVAL;
2098                 } else if (qid1) {
2099                         qid = qid1;
2100                 } else if (qid == 0)
2101                         qid = rtnl_dereference(dev->qdisc)->handle;
2102
2103                 /* Now qid is genuine qdisc handle consistent
2104                  * both with parent and child.
2105                  *
2106                  * TC_H_MAJ(portid) still may be unspecified, complete it now.
2107                  */
2108                 if (portid)
2109                         portid = TC_H_MAKE(qid, portid);
2110         } else {
2111                 if (qid == 0)
2112                         qid = rtnl_dereference(dev->qdisc)->handle;
2113         }
2114
2115         /* OK. Locate qdisc */
2116         q = qdisc_lookup(dev, qid);
2117         if (!q)
2118                 return -ENOENT;
2119
2120         /* An check that it supports classes */
2121         cops = q->ops->cl_ops;
2122         if (cops == NULL)
2123                 return -EINVAL;
2124
2125         /* Now try to get class */
2126         if (clid == 0) {
2127                 if (portid == TC_H_ROOT)
2128                         clid = qid;
2129         } else
2130                 clid = TC_H_MAKE(qid, clid);
2131
2132         if (clid)
2133                 cl = cops->find(q, clid);
2134
2135         if (cl == 0) {
2136                 err = -ENOENT;
2137                 if (n->nlmsg_type != RTM_NEWTCLASS ||
2138                     !(n->nlmsg_flags & NLM_F_CREATE))
2139                         goto out;
2140         } else {
2141                 switch (n->nlmsg_type) {
2142                 case RTM_NEWTCLASS:
2143                         err = -EEXIST;
2144                         if (n->nlmsg_flags & NLM_F_EXCL)
2145                                 goto out;
2146                         break;
2147                 case RTM_DELTCLASS:
2148                         err = tclass_del_notify(net, cops, skb, n, q, cl, extack);
2149                         /* Unbind the class with flilters with 0 */
2150                         tc_bind_tclass(q, portid, clid, 0);
2151                         goto out;
2152                 case RTM_GETTCLASS:
2153                         err = tclass_notify(net, skb, n, q, cl, RTM_NEWTCLASS, extack);
2154                         goto out;
2155                 default:
2156                         err = -EINVAL;
2157                         goto out;
2158                 }
2159         }
2160
2161         if (tca[TCA_INGRESS_BLOCK] || tca[TCA_EGRESS_BLOCK]) {
2162                 NL_SET_ERR_MSG(extack, "Shared blocks are not supported for classes");
2163                 return -EOPNOTSUPP;
2164         }
2165
2166         new_cl = cl;
2167         err = -EOPNOTSUPP;
2168         if (cops->change)
2169                 err = cops->change(q, clid, portid, tca, &new_cl, extack);
2170         if (err == 0) {
2171                 tclass_notify(net, skb, n, q, new_cl, RTM_NEWTCLASS, extack);
2172                 /* We just create a new class, need to do reverse binding. */
2173                 if (cl != new_cl)
2174                         tc_bind_tclass(q, portid, clid, new_cl);
2175         }
2176 out:
2177         return err;
2178 }
2179
2180 struct qdisc_dump_args {
2181         struct qdisc_walker     w;
2182         struct sk_buff          *skb;
2183         struct netlink_callback *cb;
2184 };
2185
2186 static int qdisc_class_dump(struct Qdisc *q, unsigned long cl,
2187                             struct qdisc_walker *arg)
2188 {
2189         struct qdisc_dump_args *a = (struct qdisc_dump_args *)arg;
2190
2191         return tc_fill_tclass(a->skb, q, cl, NETLINK_CB(a->cb->skb).portid,
2192                               a->cb->nlh->nlmsg_seq, NLM_F_MULTI,
2193                               RTM_NEWTCLASS, NULL);
2194 }
2195
2196 static int tc_dump_tclass_qdisc(struct Qdisc *q, struct sk_buff *skb,
2197                                 struct tcmsg *tcm, struct netlink_callback *cb,
2198                                 int *t_p, int s_t)
2199 {
2200         struct qdisc_dump_args arg;
2201
2202         if (tc_qdisc_dump_ignore(q, false) ||
2203             *t_p < s_t || !q->ops->cl_ops ||
2204             (tcm->tcm_parent &&
2205              TC_H_MAJ(tcm->tcm_parent) != q->handle)) {
2206                 (*t_p)++;
2207                 return 0;
2208         }
2209         if (*t_p > s_t)
2210                 memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0]));
2211         arg.w.fn = qdisc_class_dump;
2212         arg.skb = skb;
2213         arg.cb = cb;
2214         arg.w.stop  = 0;
2215         arg.w.skip = cb->args[1];
2216         arg.w.count = 0;
2217         q->ops->cl_ops->walk(q, &arg.w);
2218         cb->args[1] = arg.w.count;
2219         if (arg.w.stop)
2220                 return -1;
2221         (*t_p)++;
2222         return 0;
2223 }
2224
2225 static int tc_dump_tclass_root(struct Qdisc *root, struct sk_buff *skb,
2226                                struct tcmsg *tcm, struct netlink_callback *cb,
2227                                int *t_p, int s_t, bool recur)
2228 {
2229         struct Qdisc *q;
2230         int b;
2231
2232         if (!root)
2233                 return 0;
2234
2235         if (tc_dump_tclass_qdisc(root, skb, tcm, cb, t_p, s_t) < 0)
2236                 return -1;
2237
2238         if (!qdisc_dev(root) || !recur)
2239                 return 0;
2240
2241         if (tcm->tcm_parent) {
2242                 q = qdisc_match_from_root(root, TC_H_MAJ(tcm->tcm_parent));
2243                 if (q && q != root &&
2244                     tc_dump_tclass_qdisc(q, skb, tcm, cb, t_p, s_t) < 0)
2245                         return -1;
2246                 return 0;
2247         }
2248         hash_for_each(qdisc_dev(root)->qdisc_hash, b, q, hash) {
2249                 if (tc_dump_tclass_qdisc(q, skb, tcm, cb, t_p, s_t) < 0)
2250                         return -1;
2251         }
2252
2253         return 0;
2254 }
2255
2256 static int tc_dump_tclass(struct sk_buff *skb, struct netlink_callback *cb)
2257 {
2258         struct tcmsg *tcm = nlmsg_data(cb->nlh);
2259         struct net *net = sock_net(skb->sk);
2260         struct netdev_queue *dev_queue;
2261         struct net_device *dev;
2262         int t, s_t;
2263
2264         if (nlmsg_len(cb->nlh) < sizeof(*tcm))
2265                 return 0;
2266         dev = dev_get_by_index(net, tcm->tcm_ifindex);
2267         if (!dev)
2268                 return 0;
2269
2270         s_t = cb->args[0];
2271         t = 0;
2272
2273         if (tc_dump_tclass_root(rtnl_dereference(dev->qdisc),
2274                                 skb, tcm, cb, &t, s_t, true) < 0)
2275                 goto done;
2276
2277         dev_queue = dev_ingress_queue(dev);
2278         if (dev_queue &&
2279             tc_dump_tclass_root(rtnl_dereference(dev_queue->qdisc_sleeping),
2280                                 skb, tcm, cb, &t, s_t, false) < 0)
2281                 goto done;
2282
2283 done:
2284         cb->args[0] = t;
2285
2286         dev_put(dev);
2287         return skb->len;
2288 }
2289
2290 #ifdef CONFIG_PROC_FS
2291 static int psched_show(struct seq_file *seq, void *v)
2292 {
2293         seq_printf(seq, "%08x %08x %08x %08x\n",
2294                    (u32)NSEC_PER_USEC, (u32)PSCHED_TICKS2NS(1),
2295                    1000000,
2296                    (u32)NSEC_PER_SEC / hrtimer_resolution);
2297
2298         return 0;
2299 }
2300
2301 static int __net_init psched_net_init(struct net *net)
2302 {
2303         struct proc_dir_entry *e;
2304
2305         e = proc_create_single("psched", 0, net->proc_net, psched_show);
2306         if (e == NULL)
2307                 return -ENOMEM;
2308
2309         return 0;
2310 }
2311
2312 static void __net_exit psched_net_exit(struct net *net)
2313 {
2314         remove_proc_entry("psched", net->proc_net);
2315 }
2316 #else
2317 static int __net_init psched_net_init(struct net *net)
2318 {
2319         return 0;
2320 }
2321
2322 static void __net_exit psched_net_exit(struct net *net)
2323 {
2324 }
2325 #endif
2326
2327 static struct pernet_operations psched_net_ops = {
2328         .init = psched_net_init,
2329         .exit = psched_net_exit,
2330 };
2331
2332 static int __init pktsched_init(void)
2333 {
2334         int err;
2335
2336         err = register_pernet_subsys(&psched_net_ops);
2337         if (err) {
2338                 pr_err("pktsched_init: "
2339                        "cannot initialize per netns operations\n");
2340                 return err;
2341         }
2342
2343         register_qdisc(&pfifo_fast_ops);
2344         register_qdisc(&pfifo_qdisc_ops);
2345         register_qdisc(&bfifo_qdisc_ops);
2346         register_qdisc(&pfifo_head_drop_qdisc_ops);
2347         register_qdisc(&mq_qdisc_ops);
2348         register_qdisc(&noqueue_qdisc_ops);
2349
2350         rtnl_register(PF_UNSPEC, RTM_NEWQDISC, tc_modify_qdisc, NULL, 0);
2351         rtnl_register(PF_UNSPEC, RTM_DELQDISC, tc_get_qdisc, NULL, 0);
2352         rtnl_register(PF_UNSPEC, RTM_GETQDISC, tc_get_qdisc, tc_dump_qdisc,
2353                       0);
2354         rtnl_register(PF_UNSPEC, RTM_NEWTCLASS, tc_ctl_tclass, NULL, 0);
2355         rtnl_register(PF_UNSPEC, RTM_DELTCLASS, tc_ctl_tclass, NULL, 0);
2356         rtnl_register(PF_UNSPEC, RTM_GETTCLASS, tc_ctl_tclass, tc_dump_tclass,
2357                       0);
2358
2359         return 0;
2360 }
2361
2362 subsys_initcall(pktsched_init);