net/sched/sch_fq.c

   1 /*
   2  * net/sched/sch_fq.c Fair Queue Packet Scheduler (per flow pacing)
   3  *
   4  *  Copyright (C) 2013-2015 Eric Dumazet <edumazet@google.com>
   5  *
   6  *      This program is free software; you can redistribute it and/or
   7  *      modify it under the terms of the GNU General Public License
   8  *      as published by the Free Software Foundation; either version
   9  *      2 of the License, or (at your option) any later version.
  10  *
  11  *  Meant to be mostly used for locally generated traffic :
  12  *  Fast classification depends on skb->sk being set before reaching us.
  13  *  If not, (router workload), we use rxhash as fallback, with 32 bits wide hash.
  14  *  All packets belonging to a socket are considered as a 'flow'.
  15  *
  16  *  Flows are dynamically allocated and stored in a hash table of RB trees
  17  *  They are also part of one Round Robin 'queues' (new or old flows)
  18  *
  19  *  Burst avoidance (aka pacing) capability :
  20  *
  21  *  Transport (eg TCP) can set in sk->sk_pacing_rate a rate, enqueue a
  22  *  bunch of packets, and this packet scheduler adds delay between
  23  *  packets to respect rate limitation.
  24  *
  25  *  enqueue() :
  26  *   - lookup one RB tree (out of 1024 or more) to find the flow.
  27  *     If non existent flow, create it, add it to the tree.
  28  *     Add skb to the per flow list of skb (fifo).
  29  *   - Use a special fifo for high prio packets
  30  *
  31  *  dequeue() : serves flows in Round Robin
  32  *  Note : When a flow becomes empty, we do not immediately remove it from
  33  *  rb trees, for performance reasons (its expected to send additional packets,
  34  *  or SLAB cache will reuse socket for another flow)
  35  */
  36
  37 #include <linux/module.h>
  38 #include <linux/types.h>
  39 #include <linux/kernel.h>
  40 #include <linux/jiffies.h>
  41 #include <linux/string.h>
  42 #include <linux/in.h>
  43 #include <linux/errno.h>
  44 #include <linux/init.h>
  45 #include <linux/skbuff.h>
  46 #include <linux/slab.h>
  47 #include <linux/rbtree.h>
  48 #include <linux/hash.h>
  49 #include <linux/prefetch.h>
  50 #include <linux/vmalloc.h>
  51 #include <net/netlink.h>
  52 #include <net/pkt_sched.h>
  53 #include <net/sock.h>
  54 #include <net/tcp_states.h>
  55 #include <net/tcp.h>
  56
  57 /*
  58  * Per flow structure, dynamically allocated
  59  */
  60 struct fq_flow {
  61         struct sk_buff  *head;          /* list of skbs for this flow : first skb */
  62         union {
  63                 struct sk_buff *tail;   /* last skb in the list */
  64                 unsigned long  age;     /* jiffies when flow was emptied, for gc */
  65         };
  66         struct rb_node  fq_node;        /* anchor in fq_root[] trees */
  67         struct sock     *sk;
  68         int             qlen;           /* number of packets in flow queue */
  69         int             credit;
  70         u32             socket_hash;    /* sk_hash */
  71         struct fq_flow *next;           /* next pointer in RR lists, or &detached */
  72
  73         struct rb_node  rate_node;      /* anchor in q->delayed tree */
  74         u64             time_next_packet;
  75 };
  76
  77 struct fq_flow_head {
  78         struct fq_flow *first;
  79         struct fq_flow *last;
  80 };
  81
  82 struct fq_sched_data {
  83         struct fq_flow_head new_flows;
  84
  85         struct fq_flow_head old_flows;
  86
  87         struct rb_root  delayed;        /* for rate limited flows */
  88         u64             time_next_delayed_flow;
  89         unsigned long   unthrottle_latency_ns;
  90
  91         struct fq_flow  internal;       /* for non classified or high prio packets */
  92         u32             quantum;
  93         u32             initial_quantum;
  94         u32             flow_refill_delay;
  95         u32             flow_max_rate;  /* optional max rate per flow */
  96         u32             flow_plimit;    /* max packets per flow */
  97         u32             orphan_mask;    /* mask for orphaned skb */
  98         u32             low_rate_threshold;
  99         struct rb_root  *fq_root;
 100         u8              rate_enable;
 101         u8              fq_trees_log;
 102
 103         u32             flows;
 104         u32             inactive_flows;
 105         u32             throttled_flows;
 106
 107         u64             stat_gc_flows;
 108         u64             stat_internal_packets;
 109         u64             stat_tcp_retrans;
 110         u64             stat_throttled;
 111         u64             stat_flows_plimit;
 112         u64             stat_pkts_too_long;
 113         u64             stat_allocation_errors;
 114         struct qdisc_watchdog watchdog;
 115 };
 116
 117 /* special value to mark a detached flow (not on old/new list) */
 118 static struct fq_flow detached, throttled;
 119
 120 static void fq_flow_set_detached(struct fq_flow *f)
 121 {
 122         f->next = &detached;
 123         f->age = jiffies;
 124 }
 125
 126 static bool fq_flow_is_detached(const struct fq_flow *f)
 127 {
 128         return f->next == &detached;
 129 }
 130
 131 static bool fq_flow_is_throttled(const struct fq_flow *f)
 132 {
 133         return f->next == &throttled;
 134 }
 135
 136 static void fq_flow_add_tail(struct fq_flow_head *head, struct fq_flow *flow)
 137 {
 138         if (head->first)
 139                 head->last->next = flow;
 140         else
 141                 head->first = flow;
 142         head->last = flow;
 143         flow->next = NULL;
 144 }
 145
 146 static void fq_flow_unset_throttled(struct fq_sched_data *q, struct fq_flow *f)
 147 {
 148         rb_erase(&f->rate_node, &q->delayed);
 149         q->throttled_flows--;
 150         fq_flow_add_tail(&q->old_flows, f);
 151 }
 152
 153 static void fq_flow_set_throttled(struct fq_sched_data *q, struct fq_flow *f)
 154 {
 155         struct rb_node **p = &q->delayed.rb_node, *parent = NULL;
 156
 157         while (*p) {
 158                 struct fq_flow *aux;
 159
 160                 parent = *p;
 161                 aux = rb_entry(parent, struct fq_flow, rate_node);
 162                 if (f->time_next_packet >= aux->time_next_packet)
 163                         p = &parent->rb_right;
 164                 else
 165                         p = &parent->rb_left;
 166         }
 167         rb_link_node(&f->rate_node, parent, p);
 168         rb_insert_color(&f->rate_node, &q->delayed);
 169         q->throttled_flows++;
 170         q->stat_throttled++;
 171
 172         f->next = &throttled;
 173         if (q->time_next_delayed_flow > f->time_next_packet)
 174                 q->time_next_delayed_flow = f->time_next_packet;
 175 }
 176
 177
 178 static struct kmem_cache *fq_flow_cachep __read_mostly;
 179
 180
 181 /* limit number of collected flows per round */
 182 #define FQ_GC_MAX 8
 183 #define FQ_GC_AGE (3*HZ)
 184
 185 static bool fq_gc_candidate(const struct fq_flow *f)
 186 {
 187         return fq_flow_is_detached(f) &&
 188                time_after(jiffies, f->age + FQ_GC_AGE);
 189 }
 190
 191 static void fq_gc(struct fq_sched_data *q,
 192                   struct rb_root *root,
 193                   struct sock *sk)
 194 {
 195         struct fq_flow *f, *tofree[FQ_GC_MAX];
 196         struct rb_node **p, *parent;
 197         int fcnt = 0;
 198
 199         p = &root->rb_node;
 200         parent = NULL;
 201         while (*p) {
 202                 parent = *p;
 203
 204                 f = rb_entry(parent, struct fq_flow, fq_node);
 205                 if (f->sk == sk)
 206                         break;
 207
 208                 if (fq_gc_candidate(f)) {
 209                         tofree[fcnt++] = f;
 210                         if (fcnt == FQ_GC_MAX)
 211                                 break;
 212                 }
 213
 214                 if (f->sk > sk)
 215                         p = &parent->rb_right;
 216                 else
 217                         p = &parent->rb_left;
 218         }
 219
 220         q->flows -= fcnt;
 221         q->inactive_flows -= fcnt;
 222         q->stat_gc_flows += fcnt;
 223         while (fcnt) {
 224                 struct fq_flow *f = tofree[--fcnt];
 225
 226                 rb_erase(&f->fq_node, root);
 227                 kmem_cache_free(fq_flow_cachep, f);
 228         }
 229 }
 230
 231 static struct fq_flow *fq_classify(struct sk_buff *skb, struct fq_sched_data *q)
 232 {
 233         struct rb_node **p, *parent;
 234         struct sock *sk = skb->sk;
 235         struct rb_root *root;
 236         struct fq_flow *f;
 237
 238         /* warning: no starvation prevention... */
 239         if (unlikely((skb->priority & TC_PRIO_MAX) == TC_PRIO_CONTROL))
 240                 return &q->internal;
 241
 242         /* SYNACK messages are attached to a TCP_NEW_SYN_RECV request socket
 243          * or a listener (SYNCOOKIE mode)
 244          * 1) request sockets are not full blown,
 245          *    they do not contain sk_pacing_rate
 246          * 2) They are not part of a 'flow' yet
 247          * 3) We do not want to rate limit them (eg SYNFLOOD attack),
 248          *    especially if the listener set SO_MAX_PACING_RATE
 249          * 4) We pretend they are orphaned
 250          */
 251         if (!sk || sk_listener(sk)) {
 252                 unsigned long hash = skb_get_hash(skb) & q->orphan_mask;
 253
 254                 /* By forcing low order bit to 1, we make sure to not
 255                  * collide with a local flow (socket pointers are word aligned)
 256                  */
 257                 sk = (struct sock *)((hash << 1) | 1UL);
 258                 skb_orphan(skb);
 259         }
 260
 261         root = &q->fq_root[hash_ptr(sk, q->fq_trees_log)];
 262
 263         if (q->flows >= (2U << q->fq_trees_log) &&
 264             q->inactive_flows > q->flows/2)
 265                 fq_gc(q, root, sk);
 266
 267         p = &root->rb_node;
 268         parent = NULL;
 269         while (*p) {
 270                 parent = *p;
 271
 272                 f = rb_entry(parent, struct fq_flow, fq_node);
 273                 if (f->sk == sk) {
 274                         /* socket might have been reallocated, so check
 275                          * if its sk_hash is the same.
 276                          * It not, we need to refill credit with
 277                          * initial quantum
 278                          */
 279                         if (unlikely(skb->sk &&
 280                                      f->socket_hash != sk->sk_hash)) {
 281                                 f->credit = q->initial_quantum;
 282                                 f->socket_hash = sk->sk_hash;
 283                                 if (fq_flow_is_throttled(f))
 284                                         fq_flow_unset_throttled(q, f);
 285                                 f->time_next_packet = 0ULL;
 286                         }
 287                         return f;
 288                 }
 289                 if (f->sk > sk)
 290                         p = &parent->rb_right;
 291                 else
 292                         p = &parent->rb_left;
 293         }
 294
 295         f = kmem_cache_zalloc(fq_flow_cachep, GFP_ATOMIC | __GFP_NOWARN);
 296         if (unlikely(!f)) {
 297                 q->stat_allocation_errors++;
 298                 return &q->internal;
 299         }
 300         fq_flow_set_detached(f);
 301         f->sk = sk;
 302         if (skb->sk)
 303                 f->socket_hash = sk->sk_hash;
 304         f->credit = q->initial_quantum;
 305
 306         rb_link_node(&f->fq_node, parent, p);
 307         rb_insert_color(&f->fq_node, root);
 308
 309         q->flows++;
 310         q->inactive_flows++;
 311         return f;
 312 }
 313
 314
 315 /* remove one skb from head of flow queue */
 316 static struct sk_buff *fq_dequeue_head(struct Qdisc *sch, struct fq_flow *flow)
 317 {
 318         struct sk_buff *skb = flow->head;
 319
 320         if (skb) {
 321                 flow->head = skb->next;
 322                 skb->next = NULL;
 323                 flow->qlen--;
 324                 qdisc_qstats_backlog_dec(sch, skb);
 325                 sch->q.qlen--;
 326         }
 327         return skb;
 328 }
 329
 330 /* We might add in the future detection of retransmits
 331  * For the time being, just return false
 332  */
 333 static bool skb_is_retransmit(struct sk_buff *skb)
 334 {
 335         return false;
 336 }
 337
 338 /* add skb to flow queue
 339  * flow queue is a linked list, kind of FIFO, except for TCP retransmits
 340  * We special case tcp retransmits to be transmitted before other packets.
 341  * We rely on fact that TCP retransmits are unlikely, so we do not waste
 342  * a separate queue or a pointer.
 343  * head->  [retrans pkt 1]
 344  *         [retrans pkt 2]
 345  *         [ normal pkt 1]
 346  *         [ normal pkt 2]
 347  *         [ normal pkt 3]
 348  * tail->  [ normal pkt 4]
 349  */
 350 static void flow_queue_add(struct fq_flow *flow, struct sk_buff *skb)
 351 {
 352         struct sk_buff *prev, *head = flow->head;
 353
 354         skb->next = NULL;
 355         if (!head) {
 356                 flow->head = skb;
 357                 flow->tail = skb;
 358                 return;
 359         }
 360         if (likely(!skb_is_retransmit(skb))) {
 361                 flow->tail->next = skb;
 362                 flow->tail = skb;
 363                 return;
 364         }
 365
 366         /* This skb is a tcp retransmit,
 367          * find the last retrans packet in the queue
 368          */
 369         prev = NULL;
 370         while (skb_is_retransmit(head)) {
 371                 prev = head;
 372                 head = head->next;
 373                 if (!head)
 374                         break;
 375         }
 376         if (!prev) { /* no rtx packet in queue, become the new head */
 377                 skb->next = flow->head;
 378                 flow->head = skb;
 379         } else {
 380                 if (prev == flow->tail)
 381                         flow->tail = skb;
 382                 else
 383                         skb->next = prev->next;
 384                 prev->next = skb;
 385         }
 386 }
 387
 388 static int fq_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 389                       struct sk_buff **to_free)
 390 {
 391         struct fq_sched_data *q = qdisc_priv(sch);
 392         struct fq_flow *f;
 393
 394         if (unlikely(sch->q.qlen >= sch->limit))
 395                 return qdisc_drop(skb, sch, to_free);
 396
 397         f = fq_classify(skb, q);
 398         if (unlikely(f->qlen >= q->flow_plimit && f != &q->internal)) {
 399                 q->stat_flows_plimit++;
 400                 return qdisc_drop(skb, sch, to_free);
 401         }
 402
 403         f->qlen++;
 404         if (skb_is_retransmit(skb))
 405                 q->stat_tcp_retrans++;
 406         qdisc_qstats_backlog_inc(sch, skb);
 407         if (fq_flow_is_detached(f)) {
 408                 struct sock *sk = skb->sk;
 409
 410                 fq_flow_add_tail(&q->new_flows, f);
 411                 if (time_after(jiffies, f->age + q->flow_refill_delay))
 412                         f->credit = max_t(u32, f->credit, q->quantum);
 413                 if (sk && q->rate_enable) {
 414                         if (unlikely(smp_load_acquire(&sk->sk_pacing_status) !=
 415                                      SK_PACING_FQ))
 416                                 smp_store_release(&sk->sk_pacing_status,
 417                                                   SK_PACING_FQ);
 418                 }
 419                 q->inactive_flows--;
 420         }
 421
 422         /* Note: this overwrites f->age */
 423         flow_queue_add(f, skb);
 424
 425         if (unlikely(f == &q->internal)) {
 426                 q->stat_internal_packets++;
 427         }
 428         sch->q.qlen++;
 429
 430         return NET_XMIT_SUCCESS;
 431 }
 432
 433 static void fq_check_throttled(struct fq_sched_data *q, u64 now)
 434 {
 435         unsigned long sample;
 436         struct rb_node *p;
 437
 438         if (q->time_next_delayed_flow > now)
 439                 return;
 440
 441         /* Update unthrottle latency EWMA.
 442          * This is cheap and can help diagnosing timer/latency problems.
 443          */
 444         sample = (unsigned long)(now - q->time_next_delayed_flow);
 445         q->unthrottle_latency_ns -= q->unthrottle_latency_ns >> 3;
 446         q->unthrottle_latency_ns += sample >> 3;
 447
 448         q->time_next_delayed_flow = ~0ULL;
 449         while ((p = rb_first(&q->delayed)) != NULL) {
 450                 struct fq_flow *f = rb_entry(p, struct fq_flow, rate_node);
 451
 452                 if (f->time_next_packet > now) {
 453                         q->time_next_delayed_flow = f->time_next_packet;
 454                         break;
 455                 }
 456                 fq_flow_unset_throttled(q, f);
 457         }
 458 }
 459
 460 static struct sk_buff *fq_dequeue(struct Qdisc *sch)
 461 {
 462         struct fq_sched_data *q = qdisc_priv(sch);
 463         u64 now = ktime_get_ns();
 464         struct fq_flow_head *head;
 465         struct sk_buff *skb;
 466         struct fq_flow *f;
 467         u32 rate, plen;
 468
 469         skb = fq_dequeue_head(sch, &q->internal);
 470         if (skb)
 471                 goto out;
 472         fq_check_throttled(q, now);
 473 begin:
 474         head = &q->new_flows;
 475         if (!head->first) {
 476                 head = &q->old_flows;
 477                 if (!head->first) {
 478                         if (q->time_next_delayed_flow != ~0ULL)
 479                                 qdisc_watchdog_schedule_ns(&q->watchdog,
 480                                                            q->time_next_delayed_flow);
 481                         return NULL;
 482                 }
 483         }
 484         f = head->first;
 485
 486         if (f->credit <= 0) {
 487                 f->credit += q->quantum;
 488                 head->first = f->next;
 489                 fq_flow_add_tail(&q->old_flows, f);
 490                 goto begin;
 491         }
 492
 493         skb = f->head;
 494         if (unlikely(skb && now < f->time_next_packet &&
 495                      !skb_is_tcp_pure_ack(skb))) {
 496                 head->first = f->next;
 497                 fq_flow_set_throttled(q, f);
 498                 goto begin;
 499         }
 500
 501         skb = fq_dequeue_head(sch, f);
 502         if (!skb) {
 503                 head->first = f->next;
 504                 /* force a pass through old_flows to prevent starvation */
 505                 if ((head == &q->new_flows) && q->old_flows.first) {
 506                         fq_flow_add_tail(&q->old_flows, f);
 507                 } else {
 508                         fq_flow_set_detached(f);
 509                         q->inactive_flows++;
 510                 }
 511                 goto begin;
 512         }
 513         prefetch(&skb->end);
 514         f->credit -= qdisc_pkt_len(skb);
 515
 516         if (!q->rate_enable)
 517                 goto out;
 518
 519         /* Do not pace locally generated ack packets */
 520         if (skb_is_tcp_pure_ack(skb))
 521                 goto out;
 522
 523         rate = q->flow_max_rate;
 524         if (skb->sk)
 525                 rate = min(skb->sk->sk_pacing_rate, rate);
 526
 527         if (rate <= q->low_rate_threshold) {
 528                 f->credit = 0;
 529                 plen = qdisc_pkt_len(skb);
 530         } else {
 531                 plen = max(qdisc_pkt_len(skb), q->quantum);
 532                 if (f->credit > 0)
 533                         goto out;
 534         }
 535         if (rate != ~0U) {
 536                 u64 len = (u64)plen * NSEC_PER_SEC;
 537
 538                 if (likely(rate))
 539                         do_div(len, rate);
 540                 /* Since socket rate can change later,
 541                  * clamp the delay to 1 second.
 542                  * Really, providers of too big packets should be fixed !
 543                  */
 544                 if (unlikely(len > NSEC_PER_SEC)) {
 545                         len = NSEC_PER_SEC;
 546                         q->stat_pkts_too_long++;
 547                 }
 548                 /* Account for schedule/timers drifts.
 549                  * f->time_next_packet was set when prior packet was sent,
 550                  * and current time (@now) can be too late by tens of us.
 551                  */
 552                 if (f->time_next_packet)
 553                         len -= min(len/2, now - f->time_next_packet);
 554                 f->time_next_packet = now + len;
 555         }
 556 out:
 557         qdisc_bstats_update(sch, skb);
 558         return skb;
 559 }
 560
 561 static void fq_flow_purge(struct fq_flow *flow)
 562 {
 563         rtnl_kfree_skbs(flow->head, flow->tail);
 564         flow->head = NULL;
 565         flow->qlen = 0;
 566 }
 567
 568 static void fq_reset(struct Qdisc *sch)
 569 {
 570         struct fq_sched_data *q = qdisc_priv(sch);
 571         struct rb_root *root;
 572         struct rb_node *p;
 573         struct fq_flow *f;
 574         unsigned int idx;
 575
 576         sch->q.qlen = 0;
 577         sch->qstats.backlog = 0;
 578
 579         fq_flow_purge(&q->internal);
 580
 581         if (!q->fq_root)
 582                 return;
 583
 584         for (idx = 0; idx < (1U << q->fq_trees_log); idx++) {
 585                 root = &q->fq_root[idx];
 586                 while ((p = rb_first(root)) != NULL) {
 587                         f = rb_entry(p, struct fq_flow, fq_node);
 588                         rb_erase(p, root);
 589
 590                         fq_flow_purge(f);
 591
 592                         kmem_cache_free(fq_flow_cachep, f);
 593                 }
 594         }
 595         q->new_flows.first      = NULL;
 596         q->old_flows.first      = NULL;
 597         q->delayed              = RB_ROOT;
 598         q->flows                = 0;
 599         q->inactive_flows       = 0;
 600         q->throttled_flows      = 0;
 601 }
 602
 603 static void fq_rehash(struct fq_sched_data *q,
 604                       struct rb_root *old_array, u32 old_log,
 605                       struct rb_root *new_array, u32 new_log)
 606 {
 607         struct rb_node *op, **np, *parent;
 608         struct rb_root *oroot, *nroot;
 609         struct fq_flow *of, *nf;
 610         int fcnt = 0;
 611         u32 idx;
 612
 613         for (idx = 0; idx < (1U << old_log); idx++) {
 614                 oroot = &old_array[idx];
 615                 while ((op = rb_first(oroot)) != NULL) {
 616                         rb_erase(op, oroot);
 617                         of = rb_entry(op, struct fq_flow, fq_node);
 618                         if (fq_gc_candidate(of)) {
 619                                 fcnt++;
 620                                 kmem_cache_free(fq_flow_cachep, of);
 621                                 continue;
 622                         }
 623                         nroot = &new_array[hash_ptr(of->sk, new_log)];
 624
 625                         np = &nroot->rb_node;
 626                         parent = NULL;
 627                         while (*np) {
 628                                 parent = *np;
 629
 630                                 nf = rb_entry(parent, struct fq_flow, fq_node);
 631                                 BUG_ON(nf->sk == of->sk);
 632
 633                                 if (nf->sk > of->sk)
 634                                         np = &parent->rb_right;
 635                                 else
 636                                         np = &parent->rb_left;
 637                         }
 638
 639                         rb_link_node(&of->fq_node, parent, np);
 640                         rb_insert_color(&of->fq_node, nroot);
 641                 }
 642         }
 643         q->flows -= fcnt;
 644         q->inactive_flows -= fcnt;
 645         q->stat_gc_flows += fcnt;
 646 }
 647
 648 static void fq_free(void *addr)
 649 {
 650         kvfree(addr);
 651 }
 652
 653 static int fq_resize(struct Qdisc *sch, u32 log)
 654 {
 655         struct fq_sched_data *q = qdisc_priv(sch);
 656         struct rb_root *array;
 657         void *old_fq_root;
 658         u32 idx;
 659
 660         if (q->fq_root && log == q->fq_trees_log)
 661                 return 0;
 662
 663         /* If XPS was setup, we can allocate memory on right NUMA node */
 664         array = kvmalloc_node(sizeof(struct rb_root) << log, GFP_KERNEL | __GFP_RETRY_MAYFAIL,
 665                               netdev_queue_numa_node_read(sch->dev_queue));
 666         if (!array)
 667                 return -ENOMEM;
 668
 669         for (idx = 0; idx < (1U << log); idx++)
 670                 array[idx] = RB_ROOT;
 671
 672         sch_tree_lock(sch);
 673
 674         old_fq_root = q->fq_root;
 675         if (old_fq_root)
 676                 fq_rehash(q, old_fq_root, q->fq_trees_log, array, log);
 677
 678         q->fq_root = array;
 679         q->fq_trees_log = log;
 680
 681         sch_tree_unlock(sch);
 682
 683         fq_free(old_fq_root);
 684
 685         return 0;
 686 }
 687
 688 static const struct nla_policy fq_policy[TCA_FQ_MAX + 1] = {
 689         [TCA_FQ_PLIMIT]                 = { .type = NLA_U32 },
 690         [TCA_FQ_FLOW_PLIMIT]            = { .type = NLA_U32 },
 691         [TCA_FQ_QUANTUM]                = { .type = NLA_U32 },
 692         [TCA_FQ_INITIAL_QUANTUM]        = { .type = NLA_U32 },
 693         [TCA_FQ_RATE_ENABLE]            = { .type = NLA_U32 },
 694         [TCA_FQ_FLOW_DEFAULT_RATE]      = { .type = NLA_U32 },
 695         [TCA_FQ_FLOW_MAX_RATE]          = { .type = NLA_U32 },
 696         [TCA_FQ_BUCKETS_LOG]            = { .type = NLA_U32 },
 697         [TCA_FQ_FLOW_REFILL_DELAY]      = { .type = NLA_U32 },
 698         [TCA_FQ_LOW_RATE_THRESHOLD]     = { .type = NLA_U32 },
 699 };
 700
 701 static int fq_change(struct Qdisc *sch, struct nlattr *opt,
 702                      struct netlink_ext_ack *extack)
 703 {
 704         struct fq_sched_data *q = qdisc_priv(sch);
 705         struct nlattr *tb[TCA_FQ_MAX + 1];
 706         int err, drop_count = 0;
 707         unsigned drop_len = 0;
 708         u32 fq_log;
 709
 710         if (!opt)
 711                 return -EINVAL;
 712
 713         err = nla_parse_nested(tb, TCA_FQ_MAX, opt, fq_policy, NULL);
 714         if (err < 0)
 715                 return err;
 716
 717         sch_tree_lock(sch);
 718
 719         fq_log = q->fq_trees_log;
 720
 721         if (tb[TCA_FQ_BUCKETS_LOG]) {
 722                 u32 nval = nla_get_u32(tb[TCA_FQ_BUCKETS_LOG]);
 723
 724                 if (nval >= 1 && nval <= ilog2(256*1024))
 725                         fq_log = nval;
 726                 else
 727                         err = -EINVAL;
 728         }
 729         if (tb[TCA_FQ_PLIMIT])
 730                 sch->limit = nla_get_u32(tb[TCA_FQ_PLIMIT]);
 731
 732         if (tb[TCA_FQ_FLOW_PLIMIT])
 733                 q->flow_plimit = nla_get_u32(tb[TCA_FQ_FLOW_PLIMIT]);
 734
 735         if (tb[TCA_FQ_QUANTUM]) {
 736                 u32 quantum = nla_get_u32(tb[TCA_FQ_QUANTUM]);
 737
 738                 if (quantum > 0)
 739                         q->quantum = quantum;
 740                 else
 741                         err = -EINVAL;
 742         }
 743
 744         if (tb[TCA_FQ_INITIAL_QUANTUM])
 745                 q->initial_quantum = nla_get_u32(tb[TCA_FQ_INITIAL_QUANTUM]);
 746
 747         if (tb[TCA_FQ_FLOW_DEFAULT_RATE])
 748                 pr_warn_ratelimited("sch_fq: defrate %u ignored.\n",
 749                                     nla_get_u32(tb[TCA_FQ_FLOW_DEFAULT_RATE]));
 750
 751         if (tb[TCA_FQ_FLOW_MAX_RATE])
 752                 q->flow_max_rate = nla_get_u32(tb[TCA_FQ_FLOW_MAX_RATE]);
 753
 754         if (tb[TCA_FQ_LOW_RATE_THRESHOLD])
 755                 q->low_rate_threshold =
 756                         nla_get_u32(tb[TCA_FQ_LOW_RATE_THRESHOLD]);
 757
 758         if (tb[TCA_FQ_RATE_ENABLE]) {
 759                 u32 enable = nla_get_u32(tb[TCA_FQ_RATE_ENABLE]);
 760
 761                 if (enable <= 1)
 762                         q->rate_enable = enable;
 763                 else
 764                         err = -EINVAL;
 765         }
 766
 767         if (tb[TCA_FQ_FLOW_REFILL_DELAY]) {
 768                 u32 usecs_delay = nla_get_u32(tb[TCA_FQ_FLOW_REFILL_DELAY]) ;
 769
 770                 q->flow_refill_delay = usecs_to_jiffies(usecs_delay);
 771         }
 772
 773         if (tb[TCA_FQ_ORPHAN_MASK])
 774                 q->orphan_mask = nla_get_u32(tb[TCA_FQ_ORPHAN_MASK]);
 775
 776         if (!err) {
 777                 sch_tree_unlock(sch);
 778                 err = fq_resize(sch, fq_log);
 779                 sch_tree_lock(sch);
 780         }
 781         while (sch->q.qlen > sch->limit) {
 782                 struct sk_buff *skb = fq_dequeue(sch);
 783
 784                 if (!skb)
 785                         break;
 786                 drop_len += qdisc_pkt_len(skb);
 787                 rtnl_kfree_skbs(skb, skb);
 788                 drop_count++;
 789         }
 790         qdisc_tree_reduce_backlog(sch, drop_count, drop_len);
 791
 792         sch_tree_unlock(sch);
 793         return err;
 794 }
 795
 796 static void fq_destroy(struct Qdisc *sch)
 797 {
 798         struct fq_sched_data *q = qdisc_priv(sch);
 799
 800         fq_reset(sch);
 801         fq_free(q->fq_root);
 802         qdisc_watchdog_cancel(&q->watchdog);
 803 }
 804
 805 static int fq_init(struct Qdisc *sch, struct nlattr *opt,
 806                    struct netlink_ext_ack *extack)
 807 {
 808         struct fq_sched_data *q = qdisc_priv(sch);
 809         int err;
 810
 811         sch->limit              = 10000;
 812         q->flow_plimit          = 100;
 813         q->quantum              = 2 * psched_mtu(qdisc_dev(sch));
 814         q->initial_quantum      = 10 * psched_mtu(qdisc_dev(sch));
 815         q->flow_refill_delay    = msecs_to_jiffies(40);
 816         q->flow_max_rate        = ~0U;
 817         q->time_next_delayed_flow = ~0ULL;
 818         q->rate_enable          = 1;
 819         q->new_flows.first      = NULL;
 820         q->old_flows.first      = NULL;
 821         q->delayed              = RB_ROOT;
 822         q->fq_root              = NULL;
 823         q->fq_trees_log         = ilog2(1024);
 824         q->orphan_mask          = 1024 - 1;
 825         q->low_rate_threshold   = 550000 / 8;
 826         qdisc_watchdog_init(&q->watchdog, sch);
 827
 828         if (opt)
 829                 err = fq_change(sch, opt, extack);
 830         else
 831                 err = fq_resize(sch, q->fq_trees_log);
 832
 833         return err;
 834 }
 835
 836 static int fq_dump(struct Qdisc *sch, struct sk_buff *skb)
 837 {
 838         struct fq_sched_data *q = qdisc_priv(sch);
 839         struct nlattr *opts;
 840
 841         opts = nla_nest_start(skb, TCA_OPTIONS);
 842         if (opts == NULL)
 843                 goto nla_put_failure;
 844
 845         /* TCA_FQ_FLOW_DEFAULT_RATE is not used anymore */
 846
 847         if (nla_put_u32(skb, TCA_FQ_PLIMIT, sch->limit) ||
 848             nla_put_u32(skb, TCA_FQ_FLOW_PLIMIT, q->flow_plimit) ||
 849             nla_put_u32(skb, TCA_FQ_QUANTUM, q->quantum) ||
 850             nla_put_u32(skb, TCA_FQ_INITIAL_QUANTUM, q->initial_quantum) ||
 851             nla_put_u32(skb, TCA_FQ_RATE_ENABLE, q->rate_enable) ||
 852             nla_put_u32(skb, TCA_FQ_FLOW_MAX_RATE, q->flow_max_rate) ||
 853             nla_put_u32(skb, TCA_FQ_FLOW_REFILL_DELAY,
 854                         jiffies_to_usecs(q->flow_refill_delay)) ||
 855             nla_put_u32(skb, TCA_FQ_ORPHAN_MASK, q->orphan_mask) ||
 856             nla_put_u32(skb, TCA_FQ_LOW_RATE_THRESHOLD,
 857                         q->low_rate_threshold) ||
 858             nla_put_u32(skb, TCA_FQ_BUCKETS_LOG, q->fq_trees_log))
 859                 goto nla_put_failure;
 860
 861         return nla_nest_end(skb, opts);
 862
 863 nla_put_failure:
 864         return -1;
 865 }
 866
 867 static int fq_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
 868 {
 869         struct fq_sched_data *q = qdisc_priv(sch);
 870         struct tc_fq_qd_stats st;
 871
 872         sch_tree_lock(sch);
 873
 874         st.gc_flows               = q->stat_gc_flows;
 875         st.highprio_packets       = q->stat_internal_packets;
 876         st.tcp_retrans            = q->stat_tcp_retrans;
 877         st.throttled              = q->stat_throttled;
 878         st.flows_plimit           = q->stat_flows_plimit;
 879         st.pkts_too_long          = q->stat_pkts_too_long;
 880         st.allocation_errors      = q->stat_allocation_errors;
 881         st.time_next_delayed_flow = q->time_next_delayed_flow - ktime_get_ns();
 882         st.flows                  = q->flows;
 883         st.inactive_flows         = q->inactive_flows;
 884         st.throttled_flows        = q->throttled_flows;
 885         st.unthrottle_latency_ns  = min_t(unsigned long,
 886                                           q->unthrottle_latency_ns, ~0U);
 887         sch_tree_unlock(sch);
 888
 889         return gnet_stats_copy_app(d, &st, sizeof(st));
 890 }
 891
 892 static struct Qdisc_ops fq_qdisc_ops __read_mostly = {
 893         .id             =       "fq",
 894         .priv_size      =       sizeof(struct fq_sched_data),
 895
 896         .enqueue        =       fq_enqueue,
 897         .dequeue        =       fq_dequeue,
 898         .peek           =       qdisc_peek_dequeued,
 899         .init           =       fq_init,
 900         .reset          =       fq_reset,
 901         .destroy        =       fq_destroy,
 902         .change         =       fq_change,
 903         .dump           =       fq_dump,
 904         .dump_stats     =       fq_dump_stats,
 905         .owner          =       THIS_MODULE,
 906 };
 907
 908 static int __init fq_module_init(void)
 909 {
 910         int ret;
 911
 912         fq_flow_cachep = kmem_cache_create("fq_flow_cache",
 913                                            sizeof(struct fq_flow),
 914                                            0, 0, NULL);
 915         if (!fq_flow_cachep)
 916                 return -ENOMEM;
 917
 918         ret = register_qdisc(&fq_qdisc_ops);
 919         if (ret)
 920                 kmem_cache_destroy(fq_flow_cachep);
 921         return ret;
 922 }
 923
 924 static void __exit fq_module_exit(void)
 925 {
 926         unregister_qdisc(&fq_qdisc_ops);
 927         kmem_cache_destroy(fq_flow_cachep);
 928 }
 929
 930 module_init(fq_module_init)
 931 module_exit(fq_module_exit)
 932 MODULE_AUTHOR("Eric Dumazet");
 933 MODULE_LICENSE("GPL");