1 /* 2 * net/sched/sch_netem.c Network emulator 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation; either version 7 * 2 of the License. 8 * 9 * Many of the algorithms and ideas for this came from 10 * NIST Net which is not copyrighted. 11 * 12 * Authors: Stephen Hemminger <shemminger@osdl.org> 13 * Catalin(ux aka Dino) BOIE <catab at umbrella dot ro> 14 */ 15 16 #include <linux/mm.h> 17 #include <linux/module.h> 18 #include <linux/slab.h> 19 #include <linux/types.h> 20 #include <linux/kernel.h> 21 #include <linux/errno.h> 22 #include <linux/skbuff.h> 23 #include <linux/vmalloc.h> 24 #include <linux/rtnetlink.h> 25 #include <linux/reciprocal_div.h> 26 27 #include <net/netlink.h> 28 #include <net/pkt_sched.h> 29 #include <net/inet_ecn.h> 30 31 #define VERSION "1.3" 32 33 /* Network Emulation Queuing algorithm. 34 ==================================== 35 36 Sources: [1] Mark Carson, Darrin Santay, "NIST Net - A Linux-based 37 Network Emulation Tool 38 [2] Luigi Rizzo, DummyNet for FreeBSD 39 40 ---------------------------------------------------------------- 41 42 This started out as a simple way to delay outgoing packets to 43 test TCP but has grown to include most of the functionality 44 of a full blown network emulator like NISTnet. It can delay 45 packets and add random jitter (and correlation). The random 46 distribution can be loaded from a table as well to provide 47 normal, Pareto, or experimental curves. Packet loss, 48 duplication, and reordering can also be emulated. 49 50 This qdisc does not do classification that can be handled in 51 layering other disciplines. It does not need to do bandwidth 52 control either since that can be handled by using token 53 bucket or other rate control. 54 55 Correlated Loss Generator models 56 57 Added generation of correlated loss according to the 58 "Gilbert-Elliot" model, a 4-state markov model. 59 60 References: 61 [1] NetemCLG Home http://netgroup.uniroma2.it/NetemCLG 62 [2] S. Salsano, F. Ludovici, A. Ordine, "Definition of a general 63 and intuitive loss model for packet networks and its implementation 64 in the Netem module in the Linux kernel", available in [1] 65 66 Authors: Stefano Salsano <stefano.salsano at uniroma2.it 67 Fabio Ludovici <fabio.ludovici at yahoo.it> 68 */ 69 70 struct netem_sched_data { 71 /* internal t(ime)fifo qdisc uses sch->q and sch->limit */ 72 73 /* optional qdisc for classful handling (NULL at netem init) */ 74 struct Qdisc *qdisc; 75 76 struct qdisc_watchdog watchdog; 77 78 psched_tdiff_t latency; 79 psched_tdiff_t jitter; 80 81 u32 loss; 82 u32 ecn; 83 u32 limit; 84 u32 counter; 85 u32 gap; 86 u32 duplicate; 87 u32 reorder; 88 u32 corrupt; 89 u32 rate; 90 s32 packet_overhead; 91 u32 cell_size; 92 u32 cell_size_reciprocal; 93 s32 cell_overhead; 94 95 struct crndstate { 96 u32 last; 97 u32 rho; 98 } delay_cor, loss_cor, dup_cor, reorder_cor, corrupt_cor; 99 100 struct disttable { 101 u32 size; 102 s16 table[0]; 103 } *delay_dist; 104 105 enum { 106 CLG_RANDOM, 107 CLG_4_STATES, 108 CLG_GILB_ELL, 109 } loss_model; 110 111 /* Correlated Loss Generation models */ 112 struct clgstate { 113 /* state of the Markov chain */ 114 u8 state; 115 116 /* 4-states and Gilbert-Elliot models */ 117 u32 a1; /* p13 for 4-states or p for GE */ 118 u32 a2; /* p31 for 4-states or r for GE */ 119 u32 a3; /* p32 for 4-states or h for GE */ 120 u32 a4; /* p14 for 4-states or 1-k for GE */ 121 u32 a5; /* p23 used only in 4-states */ 122 } clg; 123 124 }; 125 126 /* Time stamp put into socket buffer control block 127 * Only valid when skbs are in our internal t(ime)fifo queue. 128 */ 129 struct netem_skb_cb { 130 psched_time_t time_to_send; 131 }; 132 133 static inline struct netem_skb_cb *netem_skb_cb(struct sk_buff *skb) 134 { 135 qdisc_cb_private_validate(skb, sizeof(struct netem_skb_cb)); 136 return (struct netem_skb_cb *)qdisc_skb_cb(skb)->data; 137 } 138 139 /* init_crandom - initialize correlated random number generator 140 * Use entropy source for initial seed. 141 */ 142 static void init_crandom(struct crndstate *state, unsigned long rho) 143 { 144 state->rho = rho; 145 state->last = net_random(); 146 } 147 148 /* get_crandom - correlated random number generator 149 * Next number depends on last value. 150 * rho is scaled to avoid floating point. 151 */ 152 static u32 get_crandom(struct crndstate *state) 153 { 154 u64 value, rho; 155 unsigned long answer; 156 157 if (state->rho == 0) /* no correlation */ 158 return net_random(); 159 160 value = net_random(); 161 rho = (u64)state->rho + 1; 162 answer = (value * ((1ull<<32) - rho) + state->last * rho) >> 32; 163 state->last = answer; 164 return answer; 165 } 166 167 /* loss_4state - 4-state model loss generator 168 * Generates losses according to the 4-state Markov chain adopted in 169 * the GI (General and Intuitive) loss model. 170 */ 171 static bool loss_4state(struct netem_sched_data *q) 172 { 173 struct clgstate *clg = &q->clg; 174 u32 rnd = net_random(); 175 176 /* 177 * Makes a comparison between rnd and the transition 178 * probabilities outgoing from the current state, then decides the 179 * next state and if the next packet has to be transmitted or lost. 180 * The four states correspond to: 181 * 1 => successfully transmitted packets within a gap period 182 * 4 => isolated losses within a gap period 183 * 3 => lost packets within a burst period 184 * 2 => successfully transmitted packets within a burst period 185 */ 186 switch (clg->state) { 187 case 1: 188 if (rnd < clg->a4) { 189 clg->state = 4; 190 return true; 191 } else if (clg->a4 < rnd && rnd < clg->a1) { 192 clg->state = 3; 193 return true; 194 } else if (clg->a1 < rnd) 195 clg->state = 1; 196 197 break; 198 case 2: 199 if (rnd < clg->a5) { 200 clg->state = 3; 201 return true; 202 } else 203 clg->state = 2; 204 205 break; 206 case 3: 207 if (rnd < clg->a3) 208 clg->state = 2; 209 else if (clg->a3 < rnd && rnd < clg->a2 + clg->a3) { 210 clg->state = 1; 211 return true; 212 } else if (clg->a2 + clg->a3 < rnd) { 213 clg->state = 3; 214 return true; 215 } 216 break; 217 case 4: 218 clg->state = 1; 219 break; 220 } 221 222 return false; 223 } 224 225 /* loss_gilb_ell - Gilbert-Elliot model loss generator 226 * Generates losses according to the Gilbert-Elliot loss model or 227 * its special cases (Gilbert or Simple Gilbert) 228 * 229 * Makes a comparison between random number and the transition 230 * probabilities outgoing from the current state, then decides the 231 * next state. A second random number is extracted and the comparison 232 * with the loss probability of the current state decides if the next 233 * packet will be transmitted or lost. 234 */ 235 static bool loss_gilb_ell(struct netem_sched_data *q) 236 { 237 struct clgstate *clg = &q->clg; 238 239 switch (clg->state) { 240 case 1: 241 if (net_random() < clg->a1) 242 clg->state = 2; 243 if (net_random() < clg->a4) 244 return true; 245 case 2: 246 if (net_random() < clg->a2) 247 clg->state = 1; 248 if (clg->a3 > net_random()) 249 return true; 250 } 251 252 return false; 253 } 254 255 static bool loss_event(struct netem_sched_data *q) 256 { 257 switch (q->loss_model) { 258 case CLG_RANDOM: 259 /* Random packet drop 0 => none, ~0 => all */ 260 return q->loss && q->loss >= get_crandom(&q->loss_cor); 261 262 case CLG_4_STATES: 263 /* 4state loss model algorithm (used also for GI model) 264 * Extracts a value from the markov 4 state loss generator, 265 * if it is 1 drops a packet and if needed writes the event in 266 * the kernel logs 267 */ 268 return loss_4state(q); 269 270 case CLG_GILB_ELL: 271 /* Gilbert-Elliot loss model algorithm 272 * Extracts a value from the Gilbert-Elliot loss generator, 273 * if it is 1 drops a packet and if needed writes the event in 274 * the kernel logs 275 */ 276 return loss_gilb_ell(q); 277 } 278 279 return false; /* not reached */ 280 } 281 282 283 /* tabledist - return a pseudo-randomly distributed value with mean mu and 284 * std deviation sigma. Uses table lookup to approximate the desired 285 * distribution, and a uniformly-distributed pseudo-random source. 286 */ 287 static psched_tdiff_t tabledist(psched_tdiff_t mu, psched_tdiff_t sigma, 288 struct crndstate *state, 289 const struct disttable *dist) 290 { 291 psched_tdiff_t x; 292 long t; 293 u32 rnd; 294 295 if (sigma == 0) 296 return mu; 297 298 rnd = get_crandom(state); 299 300 /* default uniform distribution */ 301 if (dist == NULL) 302 return (rnd % (2*sigma)) - sigma + mu; 303 304 t = dist->table[rnd % dist->size]; 305 x = (sigma % NETEM_DIST_SCALE) * t; 306 if (x >= 0) 307 x += NETEM_DIST_SCALE/2; 308 else 309 x -= NETEM_DIST_SCALE/2; 310 311 return x / NETEM_DIST_SCALE + (sigma / NETEM_DIST_SCALE) * t + mu; 312 } 313 314 static psched_time_t packet_len_2_sched_time(unsigned int len, struct netem_sched_data *q) 315 { 316 u64 ticks; 317 318 len += q->packet_overhead; 319 320 if (q->cell_size) { 321 u32 cells = reciprocal_divide(len, q->cell_size_reciprocal); 322 323 if (len > cells * q->cell_size) /* extra cell needed for remainder */ 324 cells++; 325 len = cells * (q->cell_size + q->cell_overhead); 326 } 327 328 ticks = (u64)len * NSEC_PER_SEC; 329 330 do_div(ticks, q->rate); 331 return PSCHED_NS2TICKS(ticks); 332 } 333 334 static void tfifo_enqueue(struct sk_buff *nskb, struct Qdisc *sch) 335 { 336 struct sk_buff_head *list = &sch->q; 337 psched_time_t tnext = netem_skb_cb(nskb)->time_to_send; 338 struct sk_buff *skb = skb_peek_tail(list); 339 340 /* Optimize for add at tail */ 341 if (likely(!skb || tnext >= netem_skb_cb(skb)->time_to_send)) 342 return __skb_queue_tail(list, nskb); 343 344 skb_queue_reverse_walk(list, skb) { 345 if (tnext >= netem_skb_cb(skb)->time_to_send) 346 break; 347 } 348 349 __skb_queue_after(list, skb, nskb); 350 } 351 352 /* 353 * Insert one skb into qdisc. 354 * Note: parent depends on return value to account for queue length. 355 * NET_XMIT_DROP: queue length didn't change. 356 * NET_XMIT_SUCCESS: one skb was queued. 357 */ 358 static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch) 359 { 360 struct netem_sched_data *q = qdisc_priv(sch); 361 /* We don't fill cb now as skb_unshare() may invalidate it */ 362 struct netem_skb_cb *cb; 363 struct sk_buff *skb2; 364 int count = 1; 365 366 /* Random duplication */ 367 if (q->duplicate && q->duplicate >= get_crandom(&q->dup_cor)) 368 ++count; 369 370 /* Drop packet? */ 371 if (loss_event(q)) { 372 if (q->ecn && INET_ECN_set_ce(skb)) 373 sch->qstats.drops++; /* mark packet */ 374 else 375 --count; 376 } 377 if (count == 0) { 378 sch->qstats.drops++; 379 kfree_skb(skb); 380 return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; 381 } 382 383 /* If a delay is expected, orphan the skb. (orphaning usually takes 384 * place at TX completion time, so _before_ the link transit delay) 385 * Ideally, this orphaning should be done after the rate limiting 386 * module, because this breaks TCP Small Queue, and other mechanisms 387 * based on socket sk_wmem_alloc. 388 */ 389 if (q->latency || q->jitter) 390 skb_orphan(skb); 391 392 /* 393 * If we need to duplicate packet, then re-insert at top of the 394 * qdisc tree, since parent queuer expects that only one 395 * skb will be queued. 396 */ 397 if (count > 1 && (skb2 = skb_clone(skb, GFP_ATOMIC)) != NULL) { 398 struct Qdisc *rootq = qdisc_root(sch); 399 u32 dupsave = q->duplicate; /* prevent duplicating a dup... */ 400 q->duplicate = 0; 401 402 qdisc_enqueue_root(skb2, rootq); 403 q->duplicate = dupsave; 404 } 405 406 /* 407 * Randomized packet corruption. 408 * Make copy if needed since we are modifying 409 * If packet is going to be hardware checksummed, then 410 * do it now in software before we mangle it. 411 */ 412 if (q->corrupt && q->corrupt >= get_crandom(&q->corrupt_cor)) { 413 if (!(skb = skb_unshare(skb, GFP_ATOMIC)) || 414 (skb->ip_summed == CHECKSUM_PARTIAL && 415 skb_checksum_help(skb))) 416 return qdisc_drop(skb, sch); 417 418 skb->data[net_random() % skb_headlen(skb)] ^= 1<<(net_random() % 8); 419 } 420 421 if (unlikely(skb_queue_len(&sch->q) >= sch->limit)) 422 return qdisc_reshape_fail(skb, sch); 423 424 sch->qstats.backlog += qdisc_pkt_len(skb); 425 426 cb = netem_skb_cb(skb); 427 if (q->gap == 0 || /* not doing reordering */ 428 q->counter < q->gap - 1 || /* inside last reordering gap */ 429 q->reorder < get_crandom(&q->reorder_cor)) { 430 psched_time_t now; 431 psched_tdiff_t delay; 432 433 delay = tabledist(q->latency, q->jitter, 434 &q->delay_cor, q->delay_dist); 435 436 now = psched_get_time(); 437 438 if (q->rate) { 439 struct sk_buff_head *list = &sch->q; 440 441 delay += packet_len_2_sched_time(skb->len, q); 442 443 if (!skb_queue_empty(list)) { 444 /* 445 * Last packet in queue is reference point (now). 446 * First packet in queue is already in flight, 447 * calculate this time bonus and substract 448 * from delay. 449 */ 450 delay -= now - netem_skb_cb(skb_peek(list))->time_to_send; 451 now = netem_skb_cb(skb_peek_tail(list))->time_to_send; 452 } 453 } 454 455 cb->time_to_send = now + delay; 456 ++q->counter; 457 tfifo_enqueue(skb, sch); 458 } else { 459 /* 460 * Do re-ordering by putting one out of N packets at the front 461 * of the queue. 462 */ 463 cb->time_to_send = psched_get_time(); 464 q->counter = 0; 465 466 __skb_queue_head(&sch->q, skb); 467 sch->qstats.requeues++; 468 } 469 470 return NET_XMIT_SUCCESS; 471 } 472 473 static unsigned int netem_drop(struct Qdisc *sch) 474 { 475 struct netem_sched_data *q = qdisc_priv(sch); 476 unsigned int len; 477 478 len = qdisc_queue_drop(sch); 479 if (!len && q->qdisc && q->qdisc->ops->drop) 480 len = q->qdisc->ops->drop(q->qdisc); 481 if (len) 482 sch->qstats.drops++; 483 484 return len; 485 } 486 487 static struct sk_buff *netem_dequeue(struct Qdisc *sch) 488 { 489 struct netem_sched_data *q = qdisc_priv(sch); 490 struct sk_buff *skb; 491 492 if (qdisc_is_throttled(sch)) 493 return NULL; 494 495 tfifo_dequeue: 496 skb = qdisc_peek_head(sch); 497 if (skb) { 498 const struct netem_skb_cb *cb = netem_skb_cb(skb); 499 500 /* if more time remaining? */ 501 if (cb->time_to_send <= psched_get_time()) { 502 __skb_unlink(skb, &sch->q); 503 sch->qstats.backlog -= qdisc_pkt_len(skb); 504 505 #ifdef CONFIG_NET_CLS_ACT 506 /* 507 * If it's at ingress let's pretend the delay is 508 * from the network (tstamp will be updated). 509 */ 510 if (G_TC_FROM(skb->tc_verd) & AT_INGRESS) 511 skb->tstamp.tv64 = 0; 512 #endif 513 514 if (q->qdisc) { 515 int err = qdisc_enqueue(skb, q->qdisc); 516 517 if (unlikely(err != NET_XMIT_SUCCESS)) { 518 if (net_xmit_drop_count(err)) { 519 sch->qstats.drops++; 520 qdisc_tree_decrease_qlen(sch, 1); 521 } 522 } 523 goto tfifo_dequeue; 524 } 525 deliver: 526 qdisc_unthrottled(sch); 527 qdisc_bstats_update(sch, skb); 528 return skb; 529 } 530 531 if (q->qdisc) { 532 skb = q->qdisc->ops->dequeue(q->qdisc); 533 if (skb) 534 goto deliver; 535 } 536 qdisc_watchdog_schedule(&q->watchdog, cb->time_to_send); 537 } 538 539 if (q->qdisc) { 540 skb = q->qdisc->ops->dequeue(q->qdisc); 541 if (skb) 542 goto deliver; 543 } 544 return NULL; 545 } 546 547 static void netem_reset(struct Qdisc *sch) 548 { 549 struct netem_sched_data *q = qdisc_priv(sch); 550 551 qdisc_reset_queue(sch); 552 if (q->qdisc) 553 qdisc_reset(q->qdisc); 554 qdisc_watchdog_cancel(&q->watchdog); 555 } 556 557 static void dist_free(struct disttable *d) 558 { 559 if (d) { 560 if (is_vmalloc_addr(d)) 561 vfree(d); 562 else 563 kfree(d); 564 } 565 } 566 567 /* 568 * Distribution data is a variable size payload containing 569 * signed 16 bit values. 570 */ 571 static int get_dist_table(struct Qdisc *sch, const struct nlattr *attr) 572 { 573 struct netem_sched_data *q = qdisc_priv(sch); 574 size_t n = nla_len(attr)/sizeof(__s16); 575 const __s16 *data = nla_data(attr); 576 spinlock_t *root_lock; 577 struct disttable *d; 578 int i; 579 size_t s; 580 581 if (n > NETEM_DIST_MAX) 582 return -EINVAL; 583 584 s = sizeof(struct disttable) + n * sizeof(s16); 585 d = kmalloc(s, GFP_KERNEL | __GFP_NOWARN); 586 if (!d) 587 d = vmalloc(s); 588 if (!d) 589 return -ENOMEM; 590 591 d->size = n; 592 for (i = 0; i < n; i++) 593 d->table[i] = data[i]; 594 595 root_lock = qdisc_root_sleeping_lock(sch); 596 597 spin_lock_bh(root_lock); 598 swap(q->delay_dist, d); 599 spin_unlock_bh(root_lock); 600 601 dist_free(d); 602 return 0; 603 } 604 605 static void get_correlation(struct Qdisc *sch, const struct nlattr *attr) 606 { 607 struct netem_sched_data *q = qdisc_priv(sch); 608 const struct tc_netem_corr *c = nla_data(attr); 609 610 init_crandom(&q->delay_cor, c->delay_corr); 611 init_crandom(&q->loss_cor, c->loss_corr); 612 init_crandom(&q->dup_cor, c->dup_corr); 613 } 614 615 static void get_reorder(struct Qdisc *sch, const struct nlattr *attr) 616 { 617 struct netem_sched_data *q = qdisc_priv(sch); 618 const struct tc_netem_reorder *r = nla_data(attr); 619 620 q->reorder = r->probability; 621 init_crandom(&q->reorder_cor, r->correlation); 622 } 623 624 static void get_corrupt(struct Qdisc *sch, const struct nlattr *attr) 625 { 626 struct netem_sched_data *q = qdisc_priv(sch); 627 const struct tc_netem_corrupt *r = nla_data(attr); 628 629 q->corrupt = r->probability; 630 init_crandom(&q->corrupt_cor, r->correlation); 631 } 632 633 static void get_rate(struct Qdisc *sch, const struct nlattr *attr) 634 { 635 struct netem_sched_data *q = qdisc_priv(sch); 636 const struct tc_netem_rate *r = nla_data(attr); 637 638 q->rate = r->rate; 639 q->packet_overhead = r->packet_overhead; 640 q->cell_size = r->cell_size; 641 if (q->cell_size) 642 q->cell_size_reciprocal = reciprocal_value(q->cell_size); 643 q->cell_overhead = r->cell_overhead; 644 } 645 646 static int get_loss_clg(struct Qdisc *sch, const struct nlattr *attr) 647 { 648 struct netem_sched_data *q = qdisc_priv(sch); 649 const struct nlattr *la; 650 int rem; 651 652 nla_for_each_nested(la, attr, rem) { 653 u16 type = nla_type(la); 654 655 switch(type) { 656 case NETEM_LOSS_GI: { 657 const struct tc_netem_gimodel *gi = nla_data(la); 658 659 if (nla_len(la) < sizeof(struct tc_netem_gimodel)) { 660 pr_info("netem: incorrect gi model size\n"); 661 return -EINVAL; 662 } 663 664 q->loss_model = CLG_4_STATES; 665 666 q->clg.state = 1; 667 q->clg.a1 = gi->p13; 668 q->clg.a2 = gi->p31; 669 q->clg.a3 = gi->p32; 670 q->clg.a4 = gi->p14; 671 q->clg.a5 = gi->p23; 672 break; 673 } 674 675 case NETEM_LOSS_GE: { 676 const struct tc_netem_gemodel *ge = nla_data(la); 677 678 if (nla_len(la) < sizeof(struct tc_netem_gemodel)) { 679 pr_info("netem: incorrect ge model size\n"); 680 return -EINVAL; 681 } 682 683 q->loss_model = CLG_GILB_ELL; 684 q->clg.state = 1; 685 q->clg.a1 = ge->p; 686 q->clg.a2 = ge->r; 687 q->clg.a3 = ge->h; 688 q->clg.a4 = ge->k1; 689 break; 690 } 691 692 default: 693 pr_info("netem: unknown loss type %u\n", type); 694 return -EINVAL; 695 } 696 } 697 698 return 0; 699 } 700 701 static const struct nla_policy netem_policy[TCA_NETEM_MAX + 1] = { 702 [TCA_NETEM_CORR] = { .len = sizeof(struct tc_netem_corr) }, 703 [TCA_NETEM_REORDER] = { .len = sizeof(struct tc_netem_reorder) }, 704 [TCA_NETEM_CORRUPT] = { .len = sizeof(struct tc_netem_corrupt) }, 705 [TCA_NETEM_RATE] = { .len = sizeof(struct tc_netem_rate) }, 706 [TCA_NETEM_LOSS] = { .type = NLA_NESTED }, 707 [TCA_NETEM_ECN] = { .type = NLA_U32 }, 708 }; 709 710 static int parse_attr(struct nlattr *tb[], int maxtype, struct nlattr *nla, 711 const struct nla_policy *policy, int len) 712 { 713 int nested_len = nla_len(nla) - NLA_ALIGN(len); 714 715 if (nested_len < 0) { 716 pr_info("netem: invalid attributes len %d\n", nested_len); 717 return -EINVAL; 718 } 719 720 if (nested_len >= nla_attr_size(0)) 721 return nla_parse(tb, maxtype, nla_data(nla) + NLA_ALIGN(len), 722 nested_len, policy); 723 724 memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1)); 725 return 0; 726 } 727 728 /* Parse netlink message to set options */ 729 static int netem_change(struct Qdisc *sch, struct nlattr *opt) 730 { 731 struct netem_sched_data *q = qdisc_priv(sch); 732 struct nlattr *tb[TCA_NETEM_MAX + 1]; 733 struct tc_netem_qopt *qopt; 734 int ret; 735 736 if (opt == NULL) 737 return -EINVAL; 738 739 qopt = nla_data(opt); 740 ret = parse_attr(tb, TCA_NETEM_MAX, opt, netem_policy, sizeof(*qopt)); 741 if (ret < 0) 742 return ret; 743 744 sch->limit = qopt->limit; 745 746 q->latency = qopt->latency; 747 q->jitter = qopt->jitter; 748 q->limit = qopt->limit; 749 q->gap = qopt->gap; 750 q->counter = 0; 751 q->loss = qopt->loss; 752 q->duplicate = qopt->duplicate; 753 754 /* for compatibility with earlier versions. 755 * if gap is set, need to assume 100% probability 756 */ 757 if (q->gap) 758 q->reorder = ~0; 759 760 if (tb[TCA_NETEM_CORR]) 761 get_correlation(sch, tb[TCA_NETEM_CORR]); 762 763 if (tb[TCA_NETEM_DELAY_DIST]) { 764 ret = get_dist_table(sch, tb[TCA_NETEM_DELAY_DIST]); 765 if (ret) 766 return ret; 767 } 768 769 if (tb[TCA_NETEM_REORDER]) 770 get_reorder(sch, tb[TCA_NETEM_REORDER]); 771 772 if (tb[TCA_NETEM_CORRUPT]) 773 get_corrupt(sch, tb[TCA_NETEM_CORRUPT]); 774 775 if (tb[TCA_NETEM_RATE]) 776 get_rate(sch, tb[TCA_NETEM_RATE]); 777 778 if (tb[TCA_NETEM_ECN]) 779 q->ecn = nla_get_u32(tb[TCA_NETEM_ECN]); 780 781 q->loss_model = CLG_RANDOM; 782 if (tb[TCA_NETEM_LOSS]) 783 ret = get_loss_clg(sch, tb[TCA_NETEM_LOSS]); 784 785 return ret; 786 } 787 788 static int netem_init(struct Qdisc *sch, struct nlattr *opt) 789 { 790 struct netem_sched_data *q = qdisc_priv(sch); 791 int ret; 792 793 if (!opt) 794 return -EINVAL; 795 796 qdisc_watchdog_init(&q->watchdog, sch); 797 798 q->loss_model = CLG_RANDOM; 799 ret = netem_change(sch, opt); 800 if (ret) 801 pr_info("netem: change failed\n"); 802 return ret; 803 } 804 805 static void netem_destroy(struct Qdisc *sch) 806 { 807 struct netem_sched_data *q = qdisc_priv(sch); 808 809 qdisc_watchdog_cancel(&q->watchdog); 810 if (q->qdisc) 811 qdisc_destroy(q->qdisc); 812 dist_free(q->delay_dist); 813 } 814 815 static int dump_loss_model(const struct netem_sched_data *q, 816 struct sk_buff *skb) 817 { 818 struct nlattr *nest; 819 820 nest = nla_nest_start(skb, TCA_NETEM_LOSS); 821 if (nest == NULL) 822 goto nla_put_failure; 823 824 switch (q->loss_model) { 825 case CLG_RANDOM: 826 /* legacy loss model */ 827 nla_nest_cancel(skb, nest); 828 return 0; /* no data */ 829 830 case CLG_4_STATES: { 831 struct tc_netem_gimodel gi = { 832 .p13 = q->clg.a1, 833 .p31 = q->clg.a2, 834 .p32 = q->clg.a3, 835 .p14 = q->clg.a4, 836 .p23 = q->clg.a5, 837 }; 838 839 if (nla_put(skb, NETEM_LOSS_GI, sizeof(gi), &gi)) 840 goto nla_put_failure; 841 break; 842 } 843 case CLG_GILB_ELL: { 844 struct tc_netem_gemodel ge = { 845 .p = q->clg.a1, 846 .r = q->clg.a2, 847 .h = q->clg.a3, 848 .k1 = q->clg.a4, 849 }; 850 851 if (nla_put(skb, NETEM_LOSS_GE, sizeof(ge), &ge)) 852 goto nla_put_failure; 853 break; 854 } 855 } 856 857 nla_nest_end(skb, nest); 858 return 0; 859 860 nla_put_failure: 861 nla_nest_cancel(skb, nest); 862 return -1; 863 } 864 865 static int netem_dump(struct Qdisc *sch, struct sk_buff *skb) 866 { 867 const struct netem_sched_data *q = qdisc_priv(sch); 868 struct nlattr *nla = (struct nlattr *) skb_tail_pointer(skb); 869 struct tc_netem_qopt qopt; 870 struct tc_netem_corr cor; 871 struct tc_netem_reorder reorder; 872 struct tc_netem_corrupt corrupt; 873 struct tc_netem_rate rate; 874 875 qopt.latency = q->latency; 876 qopt.jitter = q->jitter; 877 qopt.limit = q->limit; 878 qopt.loss = q->loss; 879 qopt.gap = q->gap; 880 qopt.duplicate = q->duplicate; 881 if (nla_put(skb, TCA_OPTIONS, sizeof(qopt), &qopt)) 882 goto nla_put_failure; 883 884 cor.delay_corr = q->delay_cor.rho; 885 cor.loss_corr = q->loss_cor.rho; 886 cor.dup_corr = q->dup_cor.rho; 887 if (nla_put(skb, TCA_NETEM_CORR, sizeof(cor), &cor)) 888 goto nla_put_failure; 889 890 reorder.probability = q->reorder; 891 reorder.correlation = q->reorder_cor.rho; 892 if (nla_put(skb, TCA_NETEM_REORDER, sizeof(reorder), &reorder)) 893 goto nla_put_failure; 894 895 corrupt.probability = q->corrupt; 896 corrupt.correlation = q->corrupt_cor.rho; 897 if (nla_put(skb, TCA_NETEM_CORRUPT, sizeof(corrupt), &corrupt)) 898 goto nla_put_failure; 899 900 rate.rate = q->rate; 901 rate.packet_overhead = q->packet_overhead; 902 rate.cell_size = q->cell_size; 903 rate.cell_overhead = q->cell_overhead; 904 if (nla_put(skb, TCA_NETEM_RATE, sizeof(rate), &rate)) 905 goto nla_put_failure; 906 907 if (q->ecn && nla_put_u32(skb, TCA_NETEM_ECN, q->ecn)) 908 goto nla_put_failure; 909 910 if (dump_loss_model(q, skb) != 0) 911 goto nla_put_failure; 912 913 return nla_nest_end(skb, nla); 914 915 nla_put_failure: 916 nlmsg_trim(skb, nla); 917 return -1; 918 } 919 920 static int netem_dump_class(struct Qdisc *sch, unsigned long cl, 921 struct sk_buff *skb, struct tcmsg *tcm) 922 { 923 struct netem_sched_data *q = qdisc_priv(sch); 924 925 if (cl != 1 || !q->qdisc) /* only one class */ 926 return -ENOENT; 927 928 tcm->tcm_handle |= TC_H_MIN(1); 929 tcm->tcm_info = q->qdisc->handle; 930 931 return 0; 932 } 933 934 static int netem_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, 935 struct Qdisc **old) 936 { 937 struct netem_sched_data *q = qdisc_priv(sch); 938 939 sch_tree_lock(sch); 940 *old = q->qdisc; 941 q->qdisc = new; 942 if (*old) { 943 qdisc_tree_decrease_qlen(*old, (*old)->q.qlen); 944 qdisc_reset(*old); 945 } 946 sch_tree_unlock(sch); 947 948 return 0; 949 } 950 951 static struct Qdisc *netem_leaf(struct Qdisc *sch, unsigned long arg) 952 { 953 struct netem_sched_data *q = qdisc_priv(sch); 954 return q->qdisc; 955 } 956 957 static unsigned long netem_get(struct Qdisc *sch, u32 classid) 958 { 959 return 1; 960 } 961 962 static void netem_put(struct Qdisc *sch, unsigned long arg) 963 { 964 } 965 966 static void netem_walk(struct Qdisc *sch, struct qdisc_walker *walker) 967 { 968 if (!walker->stop) { 969 if (walker->count >= walker->skip) 970 if (walker->fn(sch, 1, walker) < 0) { 971 walker->stop = 1; 972 return; 973 } 974 walker->count++; 975 } 976 } 977 978 static const struct Qdisc_class_ops netem_class_ops = { 979 .graft = netem_graft, 980 .leaf = netem_leaf, 981 .get = netem_get, 982 .put = netem_put, 983 .walk = netem_walk, 984 .dump = netem_dump_class, 985 }; 986 987 static struct Qdisc_ops netem_qdisc_ops __read_mostly = { 988 .id = "netem", 989 .cl_ops = &netem_class_ops, 990 .priv_size = sizeof(struct netem_sched_data), 991 .enqueue = netem_enqueue, 992 .dequeue = netem_dequeue, 993 .peek = qdisc_peek_dequeued, 994 .drop = netem_drop, 995 .init = netem_init, 996 .reset = netem_reset, 997 .destroy = netem_destroy, 998 .change = netem_change, 999 .dump = netem_dump, 1000 .owner = THIS_MODULE, 1001 }; 1002 1003 1004 static int __init netem_module_init(void) 1005 { 1006 pr_info("netem: version " VERSION "\n"); 1007 return register_qdisc(&netem_qdisc_ops); 1008 } 1009 static void __exit netem_module_exit(void) 1010 { 1011 unregister_qdisc(&netem_qdisc_ops); 1012 } 1013 module_init(netem_module_init) 1014 module_exit(netem_module_exit) 1015 MODULE_LICENSE("GPL"); 1016