1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * net/sched/sch_netem.c Network emulator 4 * 5 * Many of the algorithms and ideas for this came from 6 * NIST Net which is not copyrighted. 7 * 8 * Authors: Stephen Hemminger <shemminger@osdl.org> 9 * Catalin(ux aka Dino) BOIE <catab at umbrella dot ro> 10 */ 11 12 #include <linux/mm.h> 13 #include <linux/module.h> 14 #include <linux/slab.h> 15 #include <linux/types.h> 16 #include <linux/kernel.h> 17 #include <linux/errno.h> 18 #include <linux/skbuff.h> 19 #include <linux/vmalloc.h> 20 #include <linux/prandom.h> 21 #include <linux/rtnetlink.h> 22 #include <linux/reciprocal_div.h> 23 #include <linux/rbtree.h> 24 25 #include <net/gso.h> 26 #include <net/netlink.h> 27 #include <net/pkt_sched.h> 28 #include <net/inet_ecn.h> 29 30 #define VERSION "1.3" 31 32 /* Network Emulation Queuing algorithm. 33 ==================================== 34 35 Sources: [1] Mark Carson, Darrin Santay, "NIST Net - A Linux-based 36 Network Emulation Tool 37 [2] Luigi Rizzo, DummyNet for FreeBSD 38 39 ---------------------------------------------------------------- 40 41 This started out as a simple way to delay outgoing packets to 42 test TCP but has grown to include most of the functionality 43 of a full blown network emulator like NISTnet. It can delay 44 packets and add random jitter (and correlation). The random 45 distribution can be loaded from a table as well to provide 46 normal, Pareto, or experimental curves. Packet loss, 47 duplication, and reordering can also be emulated. 48 49 This qdisc does not do classification that can be handled in 50 layering other disciplines. It does not need to do bandwidth 51 control either since that can be handled by using token 52 bucket or other rate control. 53 54 Correlated Loss Generator models 55 56 Added generation of correlated loss according to the 57 "Gilbert-Elliot" model, a 4-state markov model. 58 59 References: 60 [1] NetemCLG Home http://netgroup.uniroma2.it/NetemCLG 61 [2] S. Salsano, F. Ludovici, A. Ordine, "Definition of a general 62 and intuitive loss model for packet networks and its implementation 63 in the Netem module in the Linux kernel", available in [1] 64 65 Authors: Stefano Salsano <stefano.salsano at uniroma2.it 66 Fabio Ludovici <fabio.ludovici at yahoo.it> 67 */ 68 69 struct disttable { 70 u32 size; 71 s16 table[] __counted_by(size); 72 }; 73 74 struct netem_sched_data { 75 /* internal t(ime)fifo qdisc uses t_root and sch->limit */ 76 struct rb_root t_root; 77 78 /* a linear queue; reduces rbtree rebalancing when jitter is low */ 79 struct sk_buff *t_head; 80 struct sk_buff *t_tail; 81 82 u32 t_len; 83 84 /* optional qdisc for classful handling (NULL at netem init) */ 85 struct Qdisc *qdisc; 86 87 struct qdisc_watchdog watchdog; 88 89 s64 latency; 90 s64 jitter; 91 92 u32 loss; 93 u32 ecn; 94 u32 limit; 95 u32 counter; 96 u32 gap; 97 u32 duplicate; 98 u32 reorder; 99 u32 corrupt; 100 u64 rate; 101 s32 packet_overhead; 102 u32 cell_size; 103 struct reciprocal_value cell_size_reciprocal; 104 s32 cell_overhead; 105 106 struct crndstate { 107 u32 last; 108 u32 rho; 109 } delay_cor, loss_cor, dup_cor, reorder_cor, corrupt_cor; 110 111 struct prng { 112 u64 seed; 113 struct rnd_state prng_state; 114 } prng; 115 116 struct disttable *delay_dist; 117 118 enum { 119 CLG_RANDOM, 120 CLG_4_STATES, 121 CLG_GILB_ELL, 122 } loss_model; 123 124 enum { 125 TX_IN_GAP_PERIOD = 1, 126 TX_IN_BURST_PERIOD, 127 LOST_IN_GAP_PERIOD, 128 LOST_IN_BURST_PERIOD, 129 } _4_state_model; 130 131 enum { 132 GOOD_STATE = 1, 133 BAD_STATE, 134 } GE_state_model; 135 136 /* Correlated Loss Generation models */ 137 struct clgstate { 138 /* state of the Markov chain */ 139 u8 state; 140 141 /* 4-states and Gilbert-Elliot models */ 142 u32 a1; /* p13 for 4-states or p for GE */ 143 u32 a2; /* p31 for 4-states or r for GE */ 144 u32 a3; /* p32 for 4-states or h for GE */ 145 u32 a4; /* p14 for 4-states or 1-k for GE */ 146 u32 a5; /* p23 used only in 4-states */ 147 } clg; 148 149 struct tc_netem_slot slot_config; 150 struct slotstate { 151 u64 slot_next; 152 s32 packets_left; 153 s32 bytes_left; 154 } slot; 155 156 struct disttable *slot_dist; 157 }; 158 159 /* Time stamp put into socket buffer control block 160 * Only valid when skbs are in our internal t(ime)fifo queue. 161 * 162 * As skb->rbnode uses same storage than skb->next, skb->prev and skb->tstamp, 163 * and skb->next & skb->prev are scratch space for a qdisc, 164 * we save skb->tstamp value in skb->cb[] before destroying it. 165 */ 166 struct netem_skb_cb { 167 u64 time_to_send; 168 }; 169 170 static inline struct netem_skb_cb *netem_skb_cb(struct sk_buff *skb) 171 { 172 /* we assume we can use skb next/prev/tstamp as storage for rb_node */ 173 qdisc_cb_private_validate(skb, sizeof(struct netem_skb_cb)); 174 return (struct netem_skb_cb *)qdisc_skb_cb(skb)->data; 175 } 176 177 /* init_crandom - initialize correlated random number generator 178 * Use entropy source for initial seed. 179 */ 180 static void init_crandom(struct crndstate *state, unsigned long rho) 181 { 182 state->rho = rho; 183 state->last = get_random_u32(); 184 } 185 186 /* get_crandom - correlated random number generator 187 * Next number depends on last value. 188 * rho is scaled to avoid floating point. 189 */ 190 static u32 get_crandom(struct crndstate *state, struct prng *p) 191 { 192 u64 value, rho; 193 unsigned long answer; 194 struct rnd_state *s = &p->prng_state; 195 196 if (!state || state->rho == 0) /* no correlation */ 197 return prandom_u32_state(s); 198 199 value = prandom_u32_state(s); 200 rho = (u64)state->rho + 1; 201 answer = (value * ((1ull<<32) - rho) + state->last * rho) >> 32; 202 state->last = answer; 203 return answer; 204 } 205 206 /* loss_4state - 4-state model loss generator 207 * Generates losses according to the 4-state Markov chain adopted in 208 * the GI (General and Intuitive) loss model. 209 */ 210 static bool loss_4state(struct netem_sched_data *q) 211 { 212 struct clgstate *clg = &q->clg; 213 u32 rnd = prandom_u32_state(&q->prng.prng_state); 214 215 /* 216 * Makes a comparison between rnd and the transition 217 * probabilities outgoing from the current state, then decides the 218 * next state and if the next packet has to be transmitted or lost. 219 * The four states correspond to: 220 * TX_IN_GAP_PERIOD => successfully transmitted packets within a gap period 221 * LOST_IN_GAP_PERIOD => isolated losses within a gap period 222 * LOST_IN_BURST_PERIOD => lost packets within a burst period 223 * TX_IN_BURST_PERIOD => successfully transmitted packets within a burst period 224 */ 225 switch (clg->state) { 226 case TX_IN_GAP_PERIOD: 227 if (rnd < clg->a4) { 228 clg->state = LOST_IN_GAP_PERIOD; 229 return true; 230 } else if (rnd < clg->a1 + clg->a4) { 231 clg->state = LOST_IN_BURST_PERIOD; 232 return true; 233 } else { 234 clg->state = TX_IN_GAP_PERIOD; 235 } 236 237 break; 238 case TX_IN_BURST_PERIOD: 239 if (rnd < clg->a5) { 240 clg->state = LOST_IN_BURST_PERIOD; 241 return true; 242 } else { 243 clg->state = TX_IN_BURST_PERIOD; 244 } 245 246 break; 247 case LOST_IN_BURST_PERIOD: 248 if (rnd < clg->a3) 249 clg->state = TX_IN_BURST_PERIOD; 250 else if (rnd < clg->a2 + clg->a3) { 251 clg->state = TX_IN_GAP_PERIOD; 252 } else { 253 clg->state = LOST_IN_BURST_PERIOD; 254 return true; 255 } 256 break; 257 case LOST_IN_GAP_PERIOD: 258 clg->state = TX_IN_GAP_PERIOD; 259 break; 260 } 261 262 return false; 263 } 264 265 /* loss_gilb_ell - Gilbert-Elliot model loss generator 266 * Generates losses according to the Gilbert-Elliot loss model or 267 * its special cases (Gilbert or Simple Gilbert) 268 * 269 * Makes a comparison between random number and the transition 270 * probabilities outgoing from the current state, then decides the 271 * next state. A second random number is extracted and the comparison 272 * with the loss probability of the current state decides if the next 273 * packet will be transmitted or lost. 274 */ 275 static bool loss_gilb_ell(struct netem_sched_data *q) 276 { 277 struct clgstate *clg = &q->clg; 278 struct rnd_state *s = &q->prng.prng_state; 279 280 switch (clg->state) { 281 case GOOD_STATE: 282 if (prandom_u32_state(s) < clg->a1) 283 clg->state = BAD_STATE; 284 if (prandom_u32_state(s) < clg->a4) 285 return true; 286 break; 287 case BAD_STATE: 288 if (prandom_u32_state(s) < clg->a2) 289 clg->state = GOOD_STATE; 290 if (prandom_u32_state(s) > clg->a3) 291 return true; 292 } 293 294 return false; 295 } 296 297 static bool loss_event(struct netem_sched_data *q) 298 { 299 switch (q->loss_model) { 300 case CLG_RANDOM: 301 /* Random packet drop 0 => none, ~0 => all */ 302 return q->loss && q->loss >= get_crandom(&q->loss_cor, &q->prng); 303 304 case CLG_4_STATES: 305 /* 4state loss model algorithm (used also for GI model) 306 * Extracts a value from the markov 4 state loss generator, 307 * if it is 1 drops a packet and if needed writes the event in 308 * the kernel logs 309 */ 310 return loss_4state(q); 311 312 case CLG_GILB_ELL: 313 /* Gilbert-Elliot loss model algorithm 314 * Extracts a value from the Gilbert-Elliot loss generator, 315 * if it is 1 drops a packet and if needed writes the event in 316 * the kernel logs 317 */ 318 return loss_gilb_ell(q); 319 } 320 321 return false; /* not reached */ 322 } 323 324 325 /* tabledist - return a pseudo-randomly distributed value with mean mu and 326 * std deviation sigma. Uses table lookup to approximate the desired 327 * distribution, and a uniformly-distributed pseudo-random source. 328 */ 329 static s64 tabledist(s64 mu, s32 sigma, 330 struct crndstate *state, 331 struct prng *prng, 332 const struct disttable *dist) 333 { 334 s64 x; 335 long t; 336 u32 rnd; 337 338 if (sigma == 0) 339 return mu; 340 341 rnd = get_crandom(state, prng); 342 343 /* default uniform distribution */ 344 if (dist == NULL) 345 return ((rnd % (2 * (u32)sigma)) + mu) - sigma; 346 347 t = dist->table[rnd % dist->size]; 348 x = (sigma % NETEM_DIST_SCALE) * t; 349 if (x >= 0) 350 x += NETEM_DIST_SCALE/2; 351 else 352 x -= NETEM_DIST_SCALE/2; 353 354 return x / NETEM_DIST_SCALE + (sigma / NETEM_DIST_SCALE) * t + mu; 355 } 356 357 static u64 packet_time_ns(u64 len, const struct netem_sched_data *q) 358 { 359 len += q->packet_overhead; 360 361 if (q->cell_size) { 362 u32 cells = reciprocal_divide(len, q->cell_size_reciprocal); 363 364 if (len > cells * q->cell_size) /* extra cell needed for remainder */ 365 cells++; 366 len = cells * (q->cell_size + q->cell_overhead); 367 } 368 369 return div64_u64(len * NSEC_PER_SEC, q->rate); 370 } 371 372 static void tfifo_reset(struct Qdisc *sch) 373 { 374 struct netem_sched_data *q = qdisc_priv(sch); 375 struct rb_node *p = rb_first(&q->t_root); 376 377 while (p) { 378 struct sk_buff *skb = rb_to_skb(p); 379 380 p = rb_next(p); 381 rb_erase(&skb->rbnode, &q->t_root); 382 rtnl_kfree_skbs(skb, skb); 383 } 384 385 rtnl_kfree_skbs(q->t_head, q->t_tail); 386 q->t_head = NULL; 387 q->t_tail = NULL; 388 q->t_len = 0; 389 } 390 391 static void tfifo_enqueue(struct sk_buff *nskb, struct Qdisc *sch) 392 { 393 struct netem_sched_data *q = qdisc_priv(sch); 394 u64 tnext = netem_skb_cb(nskb)->time_to_send; 395 396 if (!q->t_tail || tnext >= netem_skb_cb(q->t_tail)->time_to_send) { 397 if (q->t_tail) 398 q->t_tail->next = nskb; 399 else 400 q->t_head = nskb; 401 q->t_tail = nskb; 402 } else { 403 struct rb_node **p = &q->t_root.rb_node, *parent = NULL; 404 405 while (*p) { 406 struct sk_buff *skb; 407 408 parent = *p; 409 skb = rb_to_skb(parent); 410 if (tnext >= netem_skb_cb(skb)->time_to_send) 411 p = &parent->rb_right; 412 else 413 p = &parent->rb_left; 414 } 415 rb_link_node(&nskb->rbnode, parent, p); 416 rb_insert_color(&nskb->rbnode, &q->t_root); 417 } 418 q->t_len++; 419 sch->q.qlen++; 420 } 421 422 /* netem can't properly corrupt a megapacket (like we get from GSO), so instead 423 * when we statistically choose to corrupt one, we instead segment it, returning 424 * the first packet to be corrupted, and re-enqueue the remaining frames 425 */ 426 static struct sk_buff *netem_segment(struct sk_buff *skb, struct Qdisc *sch, 427 struct sk_buff **to_free) 428 { 429 struct sk_buff *segs; 430 netdev_features_t features = netif_skb_features(skb); 431 432 qdisc_skb_cb(skb)->pkt_segs = 1; 433 segs = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK); 434 435 if (IS_ERR_OR_NULL(segs)) { 436 qdisc_drop(skb, sch, to_free); 437 return NULL; 438 } 439 consume_skb(skb); 440 return segs; 441 } 442 443 /* 444 * Insert one skb into qdisc. 445 * Note: parent depends on return value to account for queue length. 446 * NET_XMIT_DROP: queue length didn't change. 447 * NET_XMIT_SUCCESS: one skb was queued. 448 */ 449 static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch, 450 struct sk_buff **to_free) 451 { 452 struct netem_sched_data *q = qdisc_priv(sch); 453 /* We don't fill cb now as skb_unshare() may invalidate it */ 454 struct netem_skb_cb *cb; 455 struct sk_buff *skb2 = NULL; 456 struct sk_buff *segs = NULL; 457 unsigned int prev_len = qdisc_pkt_len(skb); 458 int count = 1; 459 460 /* Do not fool qdisc_drop_all() */ 461 skb->prev = NULL; 462 463 /* Random duplication */ 464 if (q->duplicate && q->duplicate >= get_crandom(&q->dup_cor, &q->prng)) 465 ++count; 466 467 /* Drop packet? */ 468 if (loss_event(q)) { 469 if (q->ecn && INET_ECN_set_ce(skb)) 470 qdisc_qstats_drop(sch); /* mark packet */ 471 else 472 --count; 473 } 474 if (count == 0) { 475 qdisc_qstats_drop(sch); 476 __qdisc_drop(skb, to_free); 477 return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; 478 } 479 480 /* If a delay is expected, orphan the skb. (orphaning usually takes 481 * place at TX completion time, so _before_ the link transit delay) 482 */ 483 if (q->latency || q->jitter || q->rate) 484 skb_orphan_partial(skb); 485 486 /* 487 * If we need to duplicate packet, then clone it before 488 * original is modified. 489 */ 490 if (count > 1) 491 skb2 = skb_clone(skb, GFP_ATOMIC); 492 493 /* 494 * Randomized packet corruption. 495 * Make copy if needed since we are modifying 496 * If packet is going to be hardware checksummed, then 497 * do it now in software before we mangle it. 498 */ 499 if (q->corrupt && q->corrupt >= get_crandom(&q->corrupt_cor, &q->prng)) { 500 if (skb_is_gso(skb)) { 501 skb = netem_segment(skb, sch, to_free); 502 if (!skb) 503 goto finish_segs; 504 505 segs = skb->next; 506 skb_mark_not_on_list(skb); 507 qdisc_skb_cb(skb)->pkt_len = skb->len; 508 } 509 510 skb = skb_unshare(skb, GFP_ATOMIC); 511 if (unlikely(!skb)) { 512 qdisc_qstats_drop(sch); 513 goto finish_segs; 514 } 515 if (skb->ip_summed == CHECKSUM_PARTIAL && 516 skb_checksum_help(skb)) { 517 qdisc_drop(skb, sch, to_free); 518 skb = NULL; 519 goto finish_segs; 520 } 521 522 if (skb_headlen(skb)) 523 skb->data[get_random_u32_below(skb_headlen(skb))] ^= 524 1 << get_random_u32_below(8); 525 } 526 527 if (unlikely(sch->q.qlen >= sch->limit)) { 528 /* re-link segs, so that qdisc_drop_all() frees them all */ 529 skb->next = segs; 530 qdisc_drop_all(skb, sch, to_free); 531 if (skb2) 532 __qdisc_drop(skb2, to_free); 533 return NET_XMIT_DROP; 534 } 535 536 /* 537 * If doing duplication then re-insert at top of the 538 * qdisc tree, since parent queuer expects that only one 539 * skb will be queued. 540 */ 541 if (skb2) { 542 struct Qdisc *rootq = qdisc_root_bh(sch); 543 u32 dupsave = q->duplicate; /* prevent duplicating a dup... */ 544 545 q->duplicate = 0; 546 rootq->enqueue(skb2, rootq, to_free); 547 q->duplicate = dupsave; 548 skb2 = NULL; 549 } 550 551 qdisc_qstats_backlog_inc(sch, skb); 552 553 cb = netem_skb_cb(skb); 554 if (q->gap == 0 || /* not doing reordering */ 555 q->counter < q->gap - 1 || /* inside last reordering gap */ 556 q->reorder < get_crandom(&q->reorder_cor, &q->prng)) { 557 u64 now; 558 s64 delay; 559 560 delay = tabledist(q->latency, q->jitter, 561 &q->delay_cor, &q->prng, q->delay_dist); 562 563 now = ktime_get_ns(); 564 565 if (q->rate) { 566 struct netem_skb_cb *last = NULL; 567 568 if (sch->q.tail) 569 last = netem_skb_cb(sch->q.tail); 570 if (q->t_root.rb_node) { 571 struct sk_buff *t_skb; 572 struct netem_skb_cb *t_last; 573 574 t_skb = skb_rb_last(&q->t_root); 575 t_last = netem_skb_cb(t_skb); 576 if (!last || 577 t_last->time_to_send > last->time_to_send) 578 last = t_last; 579 } 580 if (q->t_tail) { 581 struct netem_skb_cb *t_last = 582 netem_skb_cb(q->t_tail); 583 584 if (!last || 585 t_last->time_to_send > last->time_to_send) 586 last = t_last; 587 } 588 589 if (last) { 590 /* 591 * Last packet in queue is reference point (now), 592 * calculate this time bonus and subtract 593 * from delay. 594 */ 595 delay -= last->time_to_send - now; 596 delay = max_t(s64, 0, delay); 597 now = last->time_to_send; 598 } 599 600 delay += packet_time_ns(qdisc_pkt_len(skb), q); 601 } 602 603 cb->time_to_send = now + delay; 604 ++q->counter; 605 tfifo_enqueue(skb, sch); 606 } else { 607 /* 608 * Do re-ordering by putting one out of N packets at the front 609 * of the queue. 610 */ 611 cb->time_to_send = ktime_get_ns(); 612 q->counter = 0; 613 614 __qdisc_enqueue_head(skb, &sch->q); 615 sch->qstats.requeues++; 616 } 617 618 finish_segs: 619 if (skb2) 620 __qdisc_drop(skb2, to_free); 621 622 if (segs) { 623 unsigned int len, last_len; 624 int rc, nb; 625 626 len = skb ? skb->len : 0; 627 nb = skb ? 1 : 0; 628 629 while (segs) { 630 skb2 = segs->next; 631 skb_mark_not_on_list(segs); 632 qdisc_skb_cb(segs)->pkt_len = segs->len; 633 last_len = segs->len; 634 rc = qdisc_enqueue(segs, sch, to_free); 635 if (rc != NET_XMIT_SUCCESS) { 636 if (net_xmit_drop_count(rc)) 637 qdisc_qstats_drop(sch); 638 } else { 639 nb++; 640 len += last_len; 641 } 642 segs = skb2; 643 } 644 /* Parent qdiscs accounted for 1 skb of size @prev_len */ 645 qdisc_tree_reduce_backlog(sch, -(nb - 1), -(len - prev_len)); 646 } else if (!skb) { 647 return NET_XMIT_DROP; 648 } 649 return NET_XMIT_SUCCESS; 650 } 651 652 /* Delay the next round with a new future slot with a 653 * correct number of bytes and packets. 654 */ 655 656 static void get_slot_next(struct netem_sched_data *q, u64 now) 657 { 658 s64 next_delay; 659 660 if (!q->slot_dist) 661 next_delay = q->slot_config.min_delay + 662 mul_u64_u32_shr(q->slot_config.max_delay - q->slot_config.min_delay, 663 get_random_u32(), 32); 664 else 665 next_delay = tabledist(q->slot_config.dist_delay, 666 (s32)(q->slot_config.dist_jitter), 667 NULL, &q->prng, q->slot_dist); 668 669 q->slot.slot_next = now + next_delay; 670 q->slot.packets_left = q->slot_config.max_packets; 671 q->slot.bytes_left = q->slot_config.max_bytes; 672 } 673 674 static struct sk_buff *netem_peek(struct netem_sched_data *q) 675 { 676 struct sk_buff *skb = skb_rb_first(&q->t_root); 677 u64 t1, t2; 678 679 if (!skb) 680 return q->t_head; 681 if (!q->t_head) 682 return skb; 683 684 t1 = netem_skb_cb(skb)->time_to_send; 685 t2 = netem_skb_cb(q->t_head)->time_to_send; 686 if (t1 < t2) 687 return skb; 688 return q->t_head; 689 } 690 691 static void netem_erase_head(struct netem_sched_data *q, struct sk_buff *skb) 692 { 693 if (skb == q->t_head) { 694 q->t_head = skb->next; 695 if (!q->t_head) 696 q->t_tail = NULL; 697 } else { 698 rb_erase(&skb->rbnode, &q->t_root); 699 } 700 } 701 702 static struct sk_buff *netem_dequeue(struct Qdisc *sch) 703 { 704 struct netem_sched_data *q = qdisc_priv(sch); 705 struct sk_buff *skb; 706 707 tfifo_dequeue: 708 skb = __qdisc_dequeue_head(&sch->q); 709 if (skb) { 710 deliver: 711 qdisc_qstats_backlog_dec(sch, skb); 712 qdisc_bstats_update(sch, skb); 713 return skb; 714 } 715 skb = netem_peek(q); 716 if (skb) { 717 u64 time_to_send; 718 u64 now = ktime_get_ns(); 719 720 /* if more time remaining? */ 721 time_to_send = netem_skb_cb(skb)->time_to_send; 722 if (q->slot.slot_next && q->slot.slot_next < time_to_send) 723 get_slot_next(q, now); 724 725 if (time_to_send <= now && q->slot.slot_next <= now) { 726 netem_erase_head(q, skb); 727 q->t_len--; 728 skb->next = NULL; 729 skb->prev = NULL; 730 /* skb->dev shares skb->rbnode area, 731 * we need to restore its value. 732 */ 733 skb->dev = qdisc_dev(sch); 734 735 if (q->slot.slot_next) { 736 q->slot.packets_left--; 737 q->slot.bytes_left -= qdisc_pkt_len(skb); 738 if (q->slot.packets_left <= 0 || 739 q->slot.bytes_left <= 0) 740 get_slot_next(q, now); 741 } 742 743 if (q->qdisc) { 744 unsigned int pkt_len = qdisc_pkt_len(skb); 745 struct sk_buff *to_free = NULL; 746 int err; 747 748 err = qdisc_enqueue(skb, q->qdisc, &to_free); 749 kfree_skb_list(to_free); 750 if (err != NET_XMIT_SUCCESS) { 751 if (net_xmit_drop_count(err)) 752 qdisc_qstats_drop(sch); 753 sch->qstats.backlog -= pkt_len; 754 sch->q.qlen--; 755 qdisc_tree_reduce_backlog(sch, 1, pkt_len); 756 } 757 goto tfifo_dequeue; 758 } 759 sch->q.qlen--; 760 goto deliver; 761 } 762 763 if (q->qdisc) { 764 skb = q->qdisc->ops->dequeue(q->qdisc); 765 if (skb) { 766 sch->q.qlen--; 767 goto deliver; 768 } 769 } 770 771 qdisc_watchdog_schedule_ns(&q->watchdog, 772 max(time_to_send, 773 q->slot.slot_next)); 774 } 775 776 if (q->qdisc) { 777 skb = q->qdisc->ops->dequeue(q->qdisc); 778 if (skb) { 779 sch->q.qlen--; 780 goto deliver; 781 } 782 } 783 return NULL; 784 } 785 786 static void netem_reset(struct Qdisc *sch) 787 { 788 struct netem_sched_data *q = qdisc_priv(sch); 789 790 qdisc_reset_queue(sch); 791 tfifo_reset(sch); 792 if (q->qdisc) 793 qdisc_reset(q->qdisc); 794 qdisc_watchdog_cancel(&q->watchdog); 795 } 796 797 static void dist_free(struct disttable *d) 798 { 799 kvfree(d); 800 } 801 802 /* 803 * Distribution data is a variable size payload containing 804 * signed 16 bit values. 805 */ 806 807 static int get_dist_table(struct disttable **tbl, const struct nlattr *attr) 808 { 809 size_t n = nla_len(attr)/sizeof(__s16); 810 const __s16 *data = nla_data(attr); 811 struct disttable *d; 812 int i; 813 814 if (!n || n > NETEM_DIST_MAX) 815 return -EINVAL; 816 817 d = kvmalloc_flex(*d, table, n); 818 if (!d) 819 return -ENOMEM; 820 821 d->size = n; 822 for (i = 0; i < n; i++) 823 d->table[i] = data[i]; 824 825 *tbl = d; 826 return 0; 827 } 828 829 static int validate_time(const struct nlattr *attr, const char *name, 830 struct netlink_ext_ack *extack) 831 { 832 if (nla_get_s64(attr) < 0) { 833 NL_SET_ERR_MSG_ATTR_FMT(extack, attr, "negative %s", name); 834 return -EINVAL; 835 } 836 return 0; 837 } 838 839 static int validate_slot(const struct nlattr *attr, struct netlink_ext_ack *extack) 840 { 841 const struct tc_netem_slot *c = nla_data(attr); 842 843 if (c->min_delay < 0 || c->max_delay < 0) { 844 NL_SET_ERR_MSG_ATTR(extack, attr, "negative slot delay"); 845 return -EINVAL; 846 } 847 if (c->min_delay > c->max_delay) { 848 NL_SET_ERR_MSG_ATTR(extack, attr, "slot min delay greater than max delay"); 849 return -EINVAL; 850 } 851 if (c->dist_delay < 0 || c->dist_jitter < 0) { 852 NL_SET_ERR_MSG_ATTR(extack, attr, "negative dist delay"); 853 return -EINVAL; 854 } 855 if (c->max_packets < 0 || c->max_bytes < 0) { 856 NL_SET_ERR_MSG_ATTR(extack, attr, "negative slot limit"); 857 return -EINVAL; 858 } 859 return 0; 860 } 861 862 static void get_slot(struct netem_sched_data *q, const struct nlattr *attr) 863 { 864 const struct tc_netem_slot *c = nla_data(attr); 865 866 q->slot_config = *c; 867 if (q->slot_config.max_packets == 0) 868 q->slot_config.max_packets = INT_MAX; 869 if (q->slot_config.max_bytes == 0) 870 q->slot_config.max_bytes = INT_MAX; 871 872 /* capping dist_jitter to the range acceptable by tabledist() */ 873 q->slot_config.dist_jitter = min_t(__s64, INT_MAX, abs(q->slot_config.dist_jitter)); 874 875 q->slot.packets_left = q->slot_config.max_packets; 876 q->slot.bytes_left = q->slot_config.max_bytes; 877 if (q->slot_config.min_delay | q->slot_config.max_delay | 878 q->slot_config.dist_jitter) 879 q->slot.slot_next = ktime_get_ns(); 880 else 881 q->slot.slot_next = 0; 882 } 883 884 static void get_correlation(struct netem_sched_data *q, const struct nlattr *attr) 885 { 886 const struct tc_netem_corr *c = nla_data(attr); 887 888 init_crandom(&q->delay_cor, c->delay_corr); 889 init_crandom(&q->loss_cor, c->loss_corr); 890 init_crandom(&q->dup_cor, c->dup_corr); 891 } 892 893 static void get_reorder(struct netem_sched_data *q, const struct nlattr *attr) 894 { 895 const struct tc_netem_reorder *r = nla_data(attr); 896 897 q->reorder = r->probability; 898 init_crandom(&q->reorder_cor, r->correlation); 899 } 900 901 static void get_corrupt(struct netem_sched_data *q, const struct nlattr *attr) 902 { 903 const struct tc_netem_corrupt *r = nla_data(attr); 904 905 q->corrupt = r->probability; 906 init_crandom(&q->corrupt_cor, r->correlation); 907 } 908 909 static void get_rate(struct netem_sched_data *q, const struct nlattr *attr) 910 { 911 const struct tc_netem_rate *r = nla_data(attr); 912 913 q->rate = r->rate; 914 q->packet_overhead = r->packet_overhead; 915 q->cell_size = r->cell_size; 916 q->cell_overhead = r->cell_overhead; 917 if (q->cell_size) 918 q->cell_size_reciprocal = reciprocal_value(q->cell_size); 919 else 920 q->cell_size_reciprocal = (struct reciprocal_value) { 0 }; 921 } 922 923 static int get_loss_clg(struct netem_sched_data *q, const struct nlattr *attr) 924 { 925 const struct nlattr *la; 926 int rem; 927 928 nla_for_each_nested(la, attr, rem) { 929 u16 type = nla_type(la); 930 931 switch (type) { 932 case NETEM_LOSS_GI: { 933 const struct tc_netem_gimodel *gi = nla_data(la); 934 935 if (nla_len(la) < sizeof(struct tc_netem_gimodel)) { 936 pr_info("netem: incorrect gi model size\n"); 937 return -EINVAL; 938 } 939 940 q->loss_model = CLG_4_STATES; 941 942 q->clg.state = TX_IN_GAP_PERIOD; 943 q->clg.a1 = gi->p13; 944 q->clg.a2 = gi->p31; 945 q->clg.a3 = gi->p32; 946 q->clg.a4 = gi->p14; 947 q->clg.a5 = gi->p23; 948 break; 949 } 950 951 case NETEM_LOSS_GE: { 952 const struct tc_netem_gemodel *ge = nla_data(la); 953 954 if (nla_len(la) < sizeof(struct tc_netem_gemodel)) { 955 pr_info("netem: incorrect ge model size\n"); 956 return -EINVAL; 957 } 958 959 q->loss_model = CLG_GILB_ELL; 960 q->clg.state = GOOD_STATE; 961 q->clg.a1 = ge->p; 962 q->clg.a2 = ge->r; 963 q->clg.a3 = ge->h; 964 q->clg.a4 = ge->k1; 965 break; 966 } 967 968 default: 969 pr_info("netem: unknown loss type %u\n", type); 970 return -EINVAL; 971 } 972 } 973 974 return 0; 975 } 976 977 static const struct nla_policy netem_policy[TCA_NETEM_MAX + 1] = { 978 [TCA_NETEM_CORR] = { .len = sizeof(struct tc_netem_corr) }, 979 [TCA_NETEM_REORDER] = { .len = sizeof(struct tc_netem_reorder) }, 980 [TCA_NETEM_CORRUPT] = { .len = sizeof(struct tc_netem_corrupt) }, 981 [TCA_NETEM_RATE] = { .len = sizeof(struct tc_netem_rate) }, 982 [TCA_NETEM_LOSS] = { .type = NLA_NESTED }, 983 [TCA_NETEM_ECN] = { .type = NLA_U32 }, 984 [TCA_NETEM_RATE64] = { .type = NLA_U64 }, 985 [TCA_NETEM_LATENCY64] = { .type = NLA_S64 }, 986 [TCA_NETEM_JITTER64] = { .type = NLA_S64 }, 987 [TCA_NETEM_SLOT] = { .len = sizeof(struct tc_netem_slot) }, 988 [TCA_NETEM_PRNG_SEED] = { .type = NLA_U64 }, 989 }; 990 991 static int parse_attr(struct nlattr *tb[], int maxtype, struct nlattr *nla, 992 const struct nla_policy *policy, int len) 993 { 994 int nested_len = nla_len(nla) - NLA_ALIGN(len); 995 996 if (nested_len < 0) { 997 pr_info("netem: invalid attributes len %d\n", nested_len); 998 return -EINVAL; 999 } 1000 1001 if (nested_len >= nla_attr_size(0)) 1002 return nla_parse_deprecated(tb, maxtype, 1003 nla_data(nla) + NLA_ALIGN(len), 1004 nested_len, policy, NULL); 1005 1006 memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1)); 1007 return 0; 1008 } 1009 1010 static const struct Qdisc_class_ops netem_class_ops; 1011 1012 static int check_netem_in_tree(struct Qdisc *sch, bool duplicates, 1013 struct netlink_ext_ack *extack) 1014 { 1015 struct Qdisc *root, *q; 1016 unsigned int i; 1017 1018 root = qdisc_root_sleeping(sch); 1019 1020 if (sch != root && root->ops->cl_ops == &netem_class_ops) { 1021 if (duplicates || 1022 ((struct netem_sched_data *)qdisc_priv(root))->duplicate) 1023 goto err; 1024 } 1025 1026 if (!qdisc_dev(root)) 1027 return 0; 1028 1029 hash_for_each(qdisc_dev(root)->qdisc_hash, i, q, hash) { 1030 if (sch != q && q->ops->cl_ops == &netem_class_ops) { 1031 if (duplicates || 1032 ((struct netem_sched_data *)qdisc_priv(q))->duplicate) 1033 goto err; 1034 } 1035 } 1036 1037 return 0; 1038 1039 err: 1040 NL_SET_ERR_MSG(extack, 1041 "netem: cannot mix duplicating netems with other netems in tree"); 1042 return -EINVAL; 1043 } 1044 1045 /* Parse netlink message to set options */ 1046 static int netem_change(struct Qdisc *sch, struct nlattr *opt, 1047 struct netlink_ext_ack *extack) 1048 { 1049 struct netem_sched_data *q = qdisc_priv(sch); 1050 struct nlattr *tb[TCA_NETEM_MAX + 1]; 1051 struct disttable *delay_dist = NULL; 1052 struct disttable *slot_dist = NULL; 1053 struct tc_netem_qopt *qopt; 1054 struct clgstate old_clg; 1055 int old_loss_model = CLG_RANDOM; 1056 int ret; 1057 1058 qopt = nla_data(opt); 1059 ret = parse_attr(tb, TCA_NETEM_MAX, opt, netem_policy, sizeof(*qopt)); 1060 if (ret < 0) 1061 return ret; 1062 1063 if (tb[TCA_NETEM_DELAY_DIST]) { 1064 ret = get_dist_table(&delay_dist, tb[TCA_NETEM_DELAY_DIST]); 1065 if (ret) 1066 goto table_free; 1067 } 1068 1069 if (tb[TCA_NETEM_SLOT_DIST]) { 1070 ret = get_dist_table(&slot_dist, tb[TCA_NETEM_SLOT_DIST]); 1071 if (ret) 1072 goto table_free; 1073 } 1074 1075 if (tb[TCA_NETEM_SLOT]) { 1076 ret = validate_slot(tb[TCA_NETEM_SLOT], extack); 1077 if (ret) 1078 goto table_free; 1079 } 1080 1081 if (tb[TCA_NETEM_LATENCY64]) { 1082 ret = validate_time(tb[TCA_NETEM_LATENCY64], "latency", extack); 1083 if (ret) 1084 goto table_free; 1085 } 1086 1087 if (tb[TCA_NETEM_JITTER64]) { 1088 ret = validate_time(tb[TCA_NETEM_JITTER64], "jitter", extack); 1089 if (ret) 1090 goto table_free; 1091 } 1092 1093 sch_tree_lock(sch); 1094 /* backup q->clg and q->loss_model */ 1095 old_clg = q->clg; 1096 old_loss_model = q->loss_model; 1097 1098 if (tb[TCA_NETEM_LOSS]) { 1099 ret = get_loss_clg(q, tb[TCA_NETEM_LOSS]); 1100 if (ret) { 1101 q->loss_model = old_loss_model; 1102 q->clg = old_clg; 1103 goto unlock; 1104 } 1105 } else { 1106 q->loss_model = CLG_RANDOM; 1107 } 1108 1109 if (delay_dist) 1110 swap(q->delay_dist, delay_dist); 1111 if (slot_dist) 1112 swap(q->slot_dist, slot_dist); 1113 sch->limit = qopt->limit; 1114 1115 q->latency = PSCHED_TICKS2NS(qopt->latency); 1116 q->jitter = PSCHED_TICKS2NS(qopt->jitter); 1117 q->limit = qopt->limit; 1118 q->gap = qopt->gap; 1119 q->counter = 0; 1120 q->loss = qopt->loss; 1121 1122 ret = check_netem_in_tree(sch, qopt->duplicate, extack); 1123 if (ret) 1124 goto unlock; 1125 1126 q->duplicate = qopt->duplicate; 1127 1128 /* for compatibility with earlier versions. 1129 * if gap is set, need to assume 100% probability 1130 */ 1131 if (q->gap) 1132 q->reorder = ~0; 1133 1134 if (tb[TCA_NETEM_CORR]) 1135 get_correlation(q, tb[TCA_NETEM_CORR]); 1136 1137 if (tb[TCA_NETEM_REORDER]) 1138 get_reorder(q, tb[TCA_NETEM_REORDER]); 1139 1140 if (tb[TCA_NETEM_CORRUPT]) 1141 get_corrupt(q, tb[TCA_NETEM_CORRUPT]); 1142 1143 if (tb[TCA_NETEM_RATE]) 1144 get_rate(q, tb[TCA_NETEM_RATE]); 1145 1146 if (tb[TCA_NETEM_RATE64]) 1147 q->rate = max_t(u64, q->rate, 1148 nla_get_u64(tb[TCA_NETEM_RATE64])); 1149 1150 if (tb[TCA_NETEM_LATENCY64]) 1151 q->latency = nla_get_s64(tb[TCA_NETEM_LATENCY64]); 1152 1153 if (tb[TCA_NETEM_JITTER64]) 1154 q->jitter = nla_get_s64(tb[TCA_NETEM_JITTER64]); 1155 1156 if (tb[TCA_NETEM_ECN]) 1157 q->ecn = nla_get_u32(tb[TCA_NETEM_ECN]); 1158 1159 if (tb[TCA_NETEM_SLOT]) 1160 get_slot(q, tb[TCA_NETEM_SLOT]); 1161 1162 /* capping jitter to the range acceptable by tabledist() */ 1163 q->jitter = min_t(s64, abs(q->jitter), INT_MAX); 1164 1165 if (tb[TCA_NETEM_PRNG_SEED]) { 1166 q->prng.seed = nla_get_u64(tb[TCA_NETEM_PRNG_SEED]); 1167 prandom_seed_state(&q->prng.prng_state, q->prng.seed); 1168 } 1169 1170 unlock: 1171 sch_tree_unlock(sch); 1172 1173 table_free: 1174 dist_free(delay_dist); 1175 dist_free(slot_dist); 1176 return ret; 1177 } 1178 1179 static int netem_init(struct Qdisc *sch, struct nlattr *opt, 1180 struct netlink_ext_ack *extack) 1181 { 1182 struct netem_sched_data *q = qdisc_priv(sch); 1183 int ret; 1184 1185 qdisc_watchdog_init(&q->watchdog, sch); 1186 1187 if (!opt) 1188 return -EINVAL; 1189 1190 q->loss_model = CLG_RANDOM; 1191 q->prng.seed = get_random_u64(); 1192 prandom_seed_state(&q->prng.prng_state, q->prng.seed); 1193 1194 ret = netem_change(sch, opt, extack); 1195 if (ret) 1196 pr_info("netem: change failed\n"); 1197 return ret; 1198 } 1199 1200 static void netem_destroy(struct Qdisc *sch) 1201 { 1202 struct netem_sched_data *q = qdisc_priv(sch); 1203 1204 qdisc_watchdog_cancel(&q->watchdog); 1205 if (q->qdisc) 1206 qdisc_put(q->qdisc); 1207 dist_free(q->delay_dist); 1208 dist_free(q->slot_dist); 1209 } 1210 1211 static int dump_loss_model(const struct netem_sched_data *q, 1212 struct sk_buff *skb) 1213 { 1214 struct nlattr *nest; 1215 1216 nest = nla_nest_start_noflag(skb, TCA_NETEM_LOSS); 1217 if (nest == NULL) 1218 goto nla_put_failure; 1219 1220 switch (q->loss_model) { 1221 case CLG_RANDOM: 1222 /* legacy loss model */ 1223 nla_nest_cancel(skb, nest); 1224 return 0; /* no data */ 1225 1226 case CLG_4_STATES: { 1227 struct tc_netem_gimodel gi = { 1228 .p13 = q->clg.a1, 1229 .p31 = q->clg.a2, 1230 .p32 = q->clg.a3, 1231 .p14 = q->clg.a4, 1232 .p23 = q->clg.a5, 1233 }; 1234 1235 if (nla_put(skb, NETEM_LOSS_GI, sizeof(gi), &gi)) 1236 goto nla_put_failure; 1237 break; 1238 } 1239 case CLG_GILB_ELL: { 1240 struct tc_netem_gemodel ge = { 1241 .p = q->clg.a1, 1242 .r = q->clg.a2, 1243 .h = q->clg.a3, 1244 .k1 = q->clg.a4, 1245 }; 1246 1247 if (nla_put(skb, NETEM_LOSS_GE, sizeof(ge), &ge)) 1248 goto nla_put_failure; 1249 break; 1250 } 1251 } 1252 1253 nla_nest_end(skb, nest); 1254 return 0; 1255 1256 nla_put_failure: 1257 nla_nest_cancel(skb, nest); 1258 return -1; 1259 } 1260 1261 static int netem_dump(struct Qdisc *sch, struct sk_buff *skb) 1262 { 1263 const struct netem_sched_data *q = qdisc_priv(sch); 1264 struct nlattr *nla = (struct nlattr *) skb_tail_pointer(skb); 1265 struct tc_netem_qopt qopt; 1266 struct tc_netem_corr cor; 1267 struct tc_netem_reorder reorder; 1268 struct tc_netem_corrupt corrupt; 1269 struct tc_netem_rate rate; 1270 struct tc_netem_slot slot; 1271 1272 qopt.latency = min_t(psched_time_t, PSCHED_NS2TICKS(q->latency), 1273 UINT_MAX); 1274 qopt.jitter = min_t(psched_time_t, PSCHED_NS2TICKS(q->jitter), 1275 UINT_MAX); 1276 qopt.limit = q->limit; 1277 qopt.loss = q->loss; 1278 qopt.gap = q->gap; 1279 qopt.duplicate = q->duplicate; 1280 if (nla_put(skb, TCA_OPTIONS, sizeof(qopt), &qopt)) 1281 goto nla_put_failure; 1282 1283 if (nla_put(skb, TCA_NETEM_LATENCY64, sizeof(q->latency), &q->latency)) 1284 goto nla_put_failure; 1285 1286 if (nla_put(skb, TCA_NETEM_JITTER64, sizeof(q->jitter), &q->jitter)) 1287 goto nla_put_failure; 1288 1289 cor.delay_corr = q->delay_cor.rho; 1290 cor.loss_corr = q->loss_cor.rho; 1291 cor.dup_corr = q->dup_cor.rho; 1292 if (nla_put(skb, TCA_NETEM_CORR, sizeof(cor), &cor)) 1293 goto nla_put_failure; 1294 1295 reorder.probability = q->reorder; 1296 reorder.correlation = q->reorder_cor.rho; 1297 if (nla_put(skb, TCA_NETEM_REORDER, sizeof(reorder), &reorder)) 1298 goto nla_put_failure; 1299 1300 corrupt.probability = q->corrupt; 1301 corrupt.correlation = q->corrupt_cor.rho; 1302 if (nla_put(skb, TCA_NETEM_CORRUPT, sizeof(corrupt), &corrupt)) 1303 goto nla_put_failure; 1304 1305 if (q->rate >= (1ULL << 32)) { 1306 if (nla_put_u64_64bit(skb, TCA_NETEM_RATE64, q->rate, 1307 TCA_NETEM_PAD)) 1308 goto nla_put_failure; 1309 rate.rate = ~0U; 1310 } else { 1311 rate.rate = q->rate; 1312 } 1313 rate.packet_overhead = q->packet_overhead; 1314 rate.cell_size = q->cell_size; 1315 rate.cell_overhead = q->cell_overhead; 1316 if (nla_put(skb, TCA_NETEM_RATE, sizeof(rate), &rate)) 1317 goto nla_put_failure; 1318 1319 if (q->ecn && nla_put_u32(skb, TCA_NETEM_ECN, q->ecn)) 1320 goto nla_put_failure; 1321 1322 if (dump_loss_model(q, skb) != 0) 1323 goto nla_put_failure; 1324 1325 if (q->slot_config.min_delay | q->slot_config.max_delay | 1326 q->slot_config.dist_jitter) { 1327 slot = q->slot_config; 1328 if (slot.max_packets == INT_MAX) 1329 slot.max_packets = 0; 1330 if (slot.max_bytes == INT_MAX) 1331 slot.max_bytes = 0; 1332 if (nla_put(skb, TCA_NETEM_SLOT, sizeof(slot), &slot)) 1333 goto nla_put_failure; 1334 } 1335 1336 if (nla_put_u64_64bit(skb, TCA_NETEM_PRNG_SEED, q->prng.seed, 1337 TCA_NETEM_PAD)) 1338 goto nla_put_failure; 1339 1340 return nla_nest_end(skb, nla); 1341 1342 nla_put_failure: 1343 nlmsg_trim(skb, nla); 1344 return -1; 1345 } 1346 1347 static int netem_dump_class(struct Qdisc *sch, unsigned long cl, 1348 struct sk_buff *skb, struct tcmsg *tcm) 1349 { 1350 struct netem_sched_data *q = qdisc_priv(sch); 1351 1352 if (cl != 1 || !q->qdisc) /* only one class */ 1353 return -ENOENT; 1354 1355 tcm->tcm_handle |= TC_H_MIN(1); 1356 tcm->tcm_info = q->qdisc->handle; 1357 1358 return 0; 1359 } 1360 1361 static int netem_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, 1362 struct Qdisc **old, struct netlink_ext_ack *extack) 1363 { 1364 struct netem_sched_data *q = qdisc_priv(sch); 1365 1366 *old = qdisc_replace(sch, new, &q->qdisc); 1367 return 0; 1368 } 1369 1370 static struct Qdisc *netem_leaf(struct Qdisc *sch, unsigned long arg) 1371 { 1372 struct netem_sched_data *q = qdisc_priv(sch); 1373 return q->qdisc; 1374 } 1375 1376 static unsigned long netem_find(struct Qdisc *sch, u32 classid) 1377 { 1378 return 1; 1379 } 1380 1381 static void netem_walk(struct Qdisc *sch, struct qdisc_walker *walker) 1382 { 1383 if (!walker->stop) { 1384 if (!tc_qdisc_stats_dump(sch, 1, walker)) 1385 return; 1386 } 1387 } 1388 1389 static const struct Qdisc_class_ops netem_class_ops = { 1390 .graft = netem_graft, 1391 .leaf = netem_leaf, 1392 .find = netem_find, 1393 .walk = netem_walk, 1394 .dump = netem_dump_class, 1395 }; 1396 1397 static struct Qdisc_ops netem_qdisc_ops __read_mostly = { 1398 .id = "netem", 1399 .cl_ops = &netem_class_ops, 1400 .priv_size = sizeof(struct netem_sched_data), 1401 .enqueue = netem_enqueue, 1402 .dequeue = netem_dequeue, 1403 .peek = qdisc_peek_dequeued, 1404 .init = netem_init, 1405 .reset = netem_reset, 1406 .destroy = netem_destroy, 1407 .change = netem_change, 1408 .dump = netem_dump, 1409 .owner = THIS_MODULE, 1410 }; 1411 MODULE_ALIAS_NET_SCH("netem"); 1412 1413 1414 static int __init netem_module_init(void) 1415 { 1416 pr_info("netem: version " VERSION "\n"); 1417 return register_qdisc(&netem_qdisc_ops); 1418 } 1419 static void __exit netem_module_exit(void) 1420 { 1421 unregister_qdisc(&netem_qdisc_ops); 1422 } 1423 module_init(netem_module_init) 1424 module_exit(netem_module_exit) 1425 MODULE_LICENSE("GPL"); 1426 MODULE_DESCRIPTION("Network characteristics emulator qdisc"); 1427