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 #include <linux/rbtree.h> 27 28 #include <net/netlink.h> 29 #include <net/pkt_sched.h> 30 #include <net/inet_ecn.h> 31 32 #define VERSION "1.3" 33 34 /* Network Emulation Queuing algorithm. 35 ==================================== 36 37 Sources: [1] Mark Carson, Darrin Santay, "NIST Net - A Linux-based 38 Network Emulation Tool 39 [2] Luigi Rizzo, DummyNet for FreeBSD 40 41 ---------------------------------------------------------------- 42 43 This started out as a simple way to delay outgoing packets to 44 test TCP but has grown to include most of the functionality 45 of a full blown network emulator like NISTnet. It can delay 46 packets and add random jitter (and correlation). The random 47 distribution can be loaded from a table as well to provide 48 normal, Pareto, or experimental curves. Packet loss, 49 duplication, and reordering can also be emulated. 50 51 This qdisc does not do classification that can be handled in 52 layering other disciplines. It does not need to do bandwidth 53 control either since that can be handled by using token 54 bucket or other rate control. 55 56 Correlated Loss Generator models 57 58 Added generation of correlated loss according to the 59 "Gilbert-Elliot" model, a 4-state markov model. 60 61 References: 62 [1] NetemCLG Home http://netgroup.uniroma2.it/NetemCLG 63 [2] S. Salsano, F. Ludovici, A. Ordine, "Definition of a general 64 and intuitive loss model for packet networks and its implementation 65 in the Netem module in the Linux kernel", available in [1] 66 67 Authors: Stefano Salsano <stefano.salsano at uniroma2.it 68 Fabio Ludovici <fabio.ludovici at yahoo.it> 69 */ 70 71 struct netem_sched_data { 72 /* internal t(ime)fifo qdisc uses t_root and sch->limit */ 73 struct rb_root t_root; 74 75 /* optional qdisc for classful handling (NULL at netem init) */ 76 struct Qdisc *qdisc; 77 78 struct qdisc_watchdog watchdog; 79 80 psched_tdiff_t latency; 81 psched_tdiff_t jitter; 82 83 u32 loss; 84 u32 ecn; 85 u32 limit; 86 u32 counter; 87 u32 gap; 88 u32 duplicate; 89 u32 reorder; 90 u32 corrupt; 91 u32 rate; 92 s32 packet_overhead; 93 u32 cell_size; 94 u32 cell_size_reciprocal; 95 s32 cell_overhead; 96 97 struct crndstate { 98 u32 last; 99 u32 rho; 100 } delay_cor, loss_cor, dup_cor, reorder_cor, corrupt_cor; 101 102 struct disttable { 103 u32 size; 104 s16 table[0]; 105 } *delay_dist; 106 107 enum { 108 CLG_RANDOM, 109 CLG_4_STATES, 110 CLG_GILB_ELL, 111 } loss_model; 112 113 /* Correlated Loss Generation models */ 114 struct clgstate { 115 /* state of the Markov chain */ 116 u8 state; 117 118 /* 4-states and Gilbert-Elliot models */ 119 u32 a1; /* p13 for 4-states or p for GE */ 120 u32 a2; /* p31 for 4-states or r for GE */ 121 u32 a3; /* p32 for 4-states or h for GE */ 122 u32 a4; /* p14 for 4-states or 1-k for GE */ 123 u32 a5; /* p23 used only in 4-states */ 124 } clg; 125 126 }; 127 128 /* Time stamp put into socket buffer control block 129 * Only valid when skbs are in our internal t(ime)fifo queue. 130 */ 131 struct netem_skb_cb { 132 psched_time_t time_to_send; 133 ktime_t tstamp_save; 134 }; 135 136 /* Because space in skb->cb[] is tight, netem overloads skb->next/prev/tstamp 137 * to hold a rb_node structure. 138 * 139 * If struct sk_buff layout is changed, the following checks will complain. 140 */ 141 static struct rb_node *netem_rb_node(struct sk_buff *skb) 142 { 143 BUILD_BUG_ON(offsetof(struct sk_buff, next) != 0); 144 BUILD_BUG_ON(offsetof(struct sk_buff, prev) != 145 offsetof(struct sk_buff, next) + sizeof(skb->next)); 146 BUILD_BUG_ON(offsetof(struct sk_buff, tstamp) != 147 offsetof(struct sk_buff, prev) + sizeof(skb->prev)); 148 BUILD_BUG_ON(sizeof(struct rb_node) > sizeof(skb->next) + 149 sizeof(skb->prev) + 150 sizeof(skb->tstamp)); 151 return (struct rb_node *)&skb->next; 152 } 153 154 static struct sk_buff *netem_rb_to_skb(struct rb_node *rb) 155 { 156 return (struct sk_buff *)rb; 157 } 158 159 static inline struct netem_skb_cb *netem_skb_cb(struct sk_buff *skb) 160 { 161 /* we assume we can use skb next/prev/tstamp as storage for rb_node */ 162 qdisc_cb_private_validate(skb, sizeof(struct netem_skb_cb)); 163 return (struct netem_skb_cb *)qdisc_skb_cb(skb)->data; 164 } 165 166 /* init_crandom - initialize correlated random number generator 167 * Use entropy source for initial seed. 168 */ 169 static void init_crandom(struct crndstate *state, unsigned long rho) 170 { 171 state->rho = rho; 172 state->last = net_random(); 173 } 174 175 /* get_crandom - correlated random number generator 176 * Next number depends on last value. 177 * rho is scaled to avoid floating point. 178 */ 179 static u32 get_crandom(struct crndstate *state) 180 { 181 u64 value, rho; 182 unsigned long answer; 183 184 if (state->rho == 0) /* no correlation */ 185 return net_random(); 186 187 value = net_random(); 188 rho = (u64)state->rho + 1; 189 answer = (value * ((1ull<<32) - rho) + state->last * rho) >> 32; 190 state->last = answer; 191 return answer; 192 } 193 194 /* loss_4state - 4-state model loss generator 195 * Generates losses according to the 4-state Markov chain adopted in 196 * the GI (General and Intuitive) loss model. 197 */ 198 static bool loss_4state(struct netem_sched_data *q) 199 { 200 struct clgstate *clg = &q->clg; 201 u32 rnd = net_random(); 202 203 /* 204 * Makes a comparison between rnd and the transition 205 * probabilities outgoing from the current state, then decides the 206 * next state and if the next packet has to be transmitted or lost. 207 * The four states correspond to: 208 * 1 => successfully transmitted packets within a gap period 209 * 4 => isolated losses within a gap period 210 * 3 => lost packets within a burst period 211 * 2 => successfully transmitted packets within a burst period 212 */ 213 switch (clg->state) { 214 case 1: 215 if (rnd < clg->a4) { 216 clg->state = 4; 217 return true; 218 } else if (clg->a4 < rnd && rnd < clg->a1 + clg->a4) { 219 clg->state = 3; 220 return true; 221 } else if (clg->a1 + clg->a4 < rnd) 222 clg->state = 1; 223 224 break; 225 case 2: 226 if (rnd < clg->a5) { 227 clg->state = 3; 228 return true; 229 } else 230 clg->state = 2; 231 232 break; 233 case 3: 234 if (rnd < clg->a3) 235 clg->state = 2; 236 else if (clg->a3 < rnd && rnd < clg->a2 + clg->a3) { 237 clg->state = 1; 238 } else if (clg->a2 + clg->a3 < rnd) { 239 clg->state = 3; 240 return true; 241 } 242 break; 243 case 4: 244 clg->state = 1; 245 break; 246 } 247 248 return false; 249 } 250 251 /* loss_gilb_ell - Gilbert-Elliot model loss generator 252 * Generates losses according to the Gilbert-Elliot loss model or 253 * its special cases (Gilbert or Simple Gilbert) 254 * 255 * Makes a comparison between random number and the transition 256 * probabilities outgoing from the current state, then decides the 257 * next state. A second random number is extracted and the comparison 258 * with the loss probability of the current state decides if the next 259 * packet will be transmitted or lost. 260 */ 261 static bool loss_gilb_ell(struct netem_sched_data *q) 262 { 263 struct clgstate *clg = &q->clg; 264 265 switch (clg->state) { 266 case 1: 267 if (net_random() < clg->a1) 268 clg->state = 2; 269 if (net_random() < clg->a4) 270 return true; 271 break; 272 case 2: 273 if (net_random() < clg->a2) 274 clg->state = 1; 275 if (net_random() > clg->a3) 276 return true; 277 } 278 279 return false; 280 } 281 282 static bool loss_event(struct netem_sched_data *q) 283 { 284 switch (q->loss_model) { 285 case CLG_RANDOM: 286 /* Random packet drop 0 => none, ~0 => all */ 287 return q->loss && q->loss >= get_crandom(&q->loss_cor); 288 289 case CLG_4_STATES: 290 /* 4state loss model algorithm (used also for GI model) 291 * Extracts a value from the markov 4 state loss generator, 292 * if it is 1 drops a packet and if needed writes the event in 293 * the kernel logs 294 */ 295 return loss_4state(q); 296 297 case CLG_GILB_ELL: 298 /* Gilbert-Elliot loss model algorithm 299 * Extracts a value from the Gilbert-Elliot loss generator, 300 * if it is 1 drops a packet and if needed writes the event in 301 * the kernel logs 302 */ 303 return loss_gilb_ell(q); 304 } 305 306 return false; /* not reached */ 307 } 308 309 310 /* tabledist - return a pseudo-randomly distributed value with mean mu and 311 * std deviation sigma. Uses table lookup to approximate the desired 312 * distribution, and a uniformly-distributed pseudo-random source. 313 */ 314 static psched_tdiff_t tabledist(psched_tdiff_t mu, psched_tdiff_t sigma, 315 struct crndstate *state, 316 const struct disttable *dist) 317 { 318 psched_tdiff_t x; 319 long t; 320 u32 rnd; 321 322 if (sigma == 0) 323 return mu; 324 325 rnd = get_crandom(state); 326 327 /* default uniform distribution */ 328 if (dist == NULL) 329 return (rnd % (2*sigma)) - sigma + mu; 330 331 t = dist->table[rnd % dist->size]; 332 x = (sigma % NETEM_DIST_SCALE) * t; 333 if (x >= 0) 334 x += NETEM_DIST_SCALE/2; 335 else 336 x -= NETEM_DIST_SCALE/2; 337 338 return x / NETEM_DIST_SCALE + (sigma / NETEM_DIST_SCALE) * t + mu; 339 } 340 341 static psched_time_t packet_len_2_sched_time(unsigned int len, struct netem_sched_data *q) 342 { 343 u64 ticks; 344 345 len += q->packet_overhead; 346 347 if (q->cell_size) { 348 u32 cells = reciprocal_divide(len, q->cell_size_reciprocal); 349 350 if (len > cells * q->cell_size) /* extra cell needed for remainder */ 351 cells++; 352 len = cells * (q->cell_size + q->cell_overhead); 353 } 354 355 ticks = (u64)len * NSEC_PER_SEC; 356 357 do_div(ticks, q->rate); 358 return PSCHED_NS2TICKS(ticks); 359 } 360 361 static void tfifo_reset(struct Qdisc *sch) 362 { 363 struct netem_sched_data *q = qdisc_priv(sch); 364 struct rb_node *p; 365 366 while ((p = rb_first(&q->t_root))) { 367 struct sk_buff *skb = netem_rb_to_skb(p); 368 369 rb_erase(p, &q->t_root); 370 skb->next = NULL; 371 skb->prev = NULL; 372 kfree_skb(skb); 373 } 374 } 375 376 static void tfifo_enqueue(struct sk_buff *nskb, struct Qdisc *sch) 377 { 378 struct netem_sched_data *q = qdisc_priv(sch); 379 psched_time_t tnext = netem_skb_cb(nskb)->time_to_send; 380 struct rb_node **p = &q->t_root.rb_node, *parent = NULL; 381 382 while (*p) { 383 struct sk_buff *skb; 384 385 parent = *p; 386 skb = netem_rb_to_skb(parent); 387 if (tnext >= netem_skb_cb(skb)->time_to_send) 388 p = &parent->rb_right; 389 else 390 p = &parent->rb_left; 391 } 392 rb_link_node(netem_rb_node(nskb), parent, p); 393 rb_insert_color(netem_rb_node(nskb), &q->t_root); 394 sch->q.qlen++; 395 } 396 397 /* 398 * Insert one skb into qdisc. 399 * Note: parent depends on return value to account for queue length. 400 * NET_XMIT_DROP: queue length didn't change. 401 * NET_XMIT_SUCCESS: one skb was queued. 402 */ 403 static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch) 404 { 405 struct netem_sched_data *q = qdisc_priv(sch); 406 /* We don't fill cb now as skb_unshare() may invalidate it */ 407 struct netem_skb_cb *cb; 408 struct sk_buff *skb2; 409 int count = 1; 410 411 /* Random duplication */ 412 if (q->duplicate && q->duplicate >= get_crandom(&q->dup_cor)) 413 ++count; 414 415 /* Drop packet? */ 416 if (loss_event(q)) { 417 if (q->ecn && INET_ECN_set_ce(skb)) 418 sch->qstats.drops++; /* mark packet */ 419 else 420 --count; 421 } 422 if (count == 0) { 423 sch->qstats.drops++; 424 kfree_skb(skb); 425 return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; 426 } 427 428 /* If a delay is expected, orphan the skb. (orphaning usually takes 429 * place at TX completion time, so _before_ the link transit delay) 430 */ 431 if (q->latency || q->jitter) 432 skb_orphan_partial(skb); 433 434 /* 435 * If we need to duplicate packet, then re-insert at top of the 436 * qdisc tree, since parent queuer expects that only one 437 * skb will be queued. 438 */ 439 if (count > 1 && (skb2 = skb_clone(skb, GFP_ATOMIC)) != NULL) { 440 struct Qdisc *rootq = qdisc_root(sch); 441 u32 dupsave = q->duplicate; /* prevent duplicating a dup... */ 442 q->duplicate = 0; 443 444 qdisc_enqueue_root(skb2, rootq); 445 q->duplicate = dupsave; 446 } 447 448 /* 449 * Randomized packet corruption. 450 * Make copy if needed since we are modifying 451 * If packet is going to be hardware checksummed, then 452 * do it now in software before we mangle it. 453 */ 454 if (q->corrupt && q->corrupt >= get_crandom(&q->corrupt_cor)) { 455 if (!(skb = skb_unshare(skb, GFP_ATOMIC)) || 456 (skb->ip_summed == CHECKSUM_PARTIAL && 457 skb_checksum_help(skb))) 458 return qdisc_drop(skb, sch); 459 460 skb->data[net_random() % skb_headlen(skb)] ^= 1<<(net_random() % 8); 461 } 462 463 if (unlikely(skb_queue_len(&sch->q) >= sch->limit)) 464 return qdisc_reshape_fail(skb, sch); 465 466 sch->qstats.backlog += qdisc_pkt_len(skb); 467 468 cb = netem_skb_cb(skb); 469 if (q->gap == 0 || /* not doing reordering */ 470 q->counter < q->gap - 1 || /* inside last reordering gap */ 471 q->reorder < get_crandom(&q->reorder_cor)) { 472 psched_time_t now; 473 psched_tdiff_t delay; 474 475 delay = tabledist(q->latency, q->jitter, 476 &q->delay_cor, q->delay_dist); 477 478 now = psched_get_time(); 479 480 if (q->rate) { 481 struct sk_buff *last; 482 483 if (!skb_queue_empty(&sch->q)) 484 last = skb_peek_tail(&sch->q); 485 else 486 last = netem_rb_to_skb(rb_last(&q->t_root)); 487 if (last) { 488 /* 489 * Last packet in queue is reference point (now), 490 * calculate this time bonus and subtract 491 * from delay. 492 */ 493 delay -= netem_skb_cb(last)->time_to_send - now; 494 delay = max_t(psched_tdiff_t, 0, delay); 495 now = netem_skb_cb(last)->time_to_send; 496 } 497 498 delay += packet_len_2_sched_time(skb->len, q); 499 } 500 501 cb->time_to_send = now + delay; 502 cb->tstamp_save = skb->tstamp; 503 ++q->counter; 504 tfifo_enqueue(skb, sch); 505 } else { 506 /* 507 * Do re-ordering by putting one out of N packets at the front 508 * of the queue. 509 */ 510 cb->time_to_send = psched_get_time(); 511 q->counter = 0; 512 513 __skb_queue_head(&sch->q, skb); 514 sch->qstats.requeues++; 515 } 516 517 return NET_XMIT_SUCCESS; 518 } 519 520 static unsigned int netem_drop(struct Qdisc *sch) 521 { 522 struct netem_sched_data *q = qdisc_priv(sch); 523 unsigned int len; 524 525 len = qdisc_queue_drop(sch); 526 527 if (!len) { 528 struct rb_node *p = rb_first(&q->t_root); 529 530 if (p) { 531 struct sk_buff *skb = netem_rb_to_skb(p); 532 533 rb_erase(p, &q->t_root); 534 sch->q.qlen--; 535 skb->next = NULL; 536 skb->prev = NULL; 537 len = qdisc_pkt_len(skb); 538 sch->qstats.backlog -= len; 539 kfree_skb(skb); 540 } 541 } 542 if (!len && q->qdisc && q->qdisc->ops->drop) 543 len = q->qdisc->ops->drop(q->qdisc); 544 if (len) 545 sch->qstats.drops++; 546 547 return len; 548 } 549 550 static struct sk_buff *netem_dequeue(struct Qdisc *sch) 551 { 552 struct netem_sched_data *q = qdisc_priv(sch); 553 struct sk_buff *skb; 554 struct rb_node *p; 555 556 if (qdisc_is_throttled(sch)) 557 return NULL; 558 559 tfifo_dequeue: 560 skb = __skb_dequeue(&sch->q); 561 if (skb) { 562 deliver: 563 sch->qstats.backlog -= qdisc_pkt_len(skb); 564 qdisc_unthrottled(sch); 565 qdisc_bstats_update(sch, skb); 566 return skb; 567 } 568 p = rb_first(&q->t_root); 569 if (p) { 570 psched_time_t time_to_send; 571 572 skb = netem_rb_to_skb(p); 573 574 /* if more time remaining? */ 575 time_to_send = netem_skb_cb(skb)->time_to_send; 576 if (time_to_send <= psched_get_time()) { 577 rb_erase(p, &q->t_root); 578 579 sch->q.qlen--; 580 skb->next = NULL; 581 skb->prev = NULL; 582 skb->tstamp = netem_skb_cb(skb)->tstamp_save; 583 584 #ifdef CONFIG_NET_CLS_ACT 585 /* 586 * If it's at ingress let's pretend the delay is 587 * from the network (tstamp will be updated). 588 */ 589 if (G_TC_FROM(skb->tc_verd) & AT_INGRESS) 590 skb->tstamp.tv64 = 0; 591 #endif 592 593 if (q->qdisc) { 594 int err = qdisc_enqueue(skb, q->qdisc); 595 596 if (unlikely(err != NET_XMIT_SUCCESS)) { 597 if (net_xmit_drop_count(err)) { 598 sch->qstats.drops++; 599 qdisc_tree_decrease_qlen(sch, 1); 600 } 601 } 602 goto tfifo_dequeue; 603 } 604 goto deliver; 605 } 606 607 if (q->qdisc) { 608 skb = q->qdisc->ops->dequeue(q->qdisc); 609 if (skb) 610 goto deliver; 611 } 612 qdisc_watchdog_schedule(&q->watchdog, time_to_send); 613 } 614 615 if (q->qdisc) { 616 skb = q->qdisc->ops->dequeue(q->qdisc); 617 if (skb) 618 goto deliver; 619 } 620 return NULL; 621 } 622 623 static void netem_reset(struct Qdisc *sch) 624 { 625 struct netem_sched_data *q = qdisc_priv(sch); 626 627 qdisc_reset_queue(sch); 628 tfifo_reset(sch); 629 if (q->qdisc) 630 qdisc_reset(q->qdisc); 631 qdisc_watchdog_cancel(&q->watchdog); 632 } 633 634 static void dist_free(struct disttable *d) 635 { 636 if (d) { 637 if (is_vmalloc_addr(d)) 638 vfree(d); 639 else 640 kfree(d); 641 } 642 } 643 644 /* 645 * Distribution data is a variable size payload containing 646 * signed 16 bit values. 647 */ 648 static int get_dist_table(struct Qdisc *sch, const struct nlattr *attr) 649 { 650 struct netem_sched_data *q = qdisc_priv(sch); 651 size_t n = nla_len(attr)/sizeof(__s16); 652 const __s16 *data = nla_data(attr); 653 spinlock_t *root_lock; 654 struct disttable *d; 655 int i; 656 size_t s; 657 658 if (n > NETEM_DIST_MAX) 659 return -EINVAL; 660 661 s = sizeof(struct disttable) + n * sizeof(s16); 662 d = kmalloc(s, GFP_KERNEL | __GFP_NOWARN); 663 if (!d) 664 d = vmalloc(s); 665 if (!d) 666 return -ENOMEM; 667 668 d->size = n; 669 for (i = 0; i < n; i++) 670 d->table[i] = data[i]; 671 672 root_lock = qdisc_root_sleeping_lock(sch); 673 674 spin_lock_bh(root_lock); 675 swap(q->delay_dist, d); 676 spin_unlock_bh(root_lock); 677 678 dist_free(d); 679 return 0; 680 } 681 682 static void get_correlation(struct Qdisc *sch, const struct nlattr *attr) 683 { 684 struct netem_sched_data *q = qdisc_priv(sch); 685 const struct tc_netem_corr *c = nla_data(attr); 686 687 init_crandom(&q->delay_cor, c->delay_corr); 688 init_crandom(&q->loss_cor, c->loss_corr); 689 init_crandom(&q->dup_cor, c->dup_corr); 690 } 691 692 static void get_reorder(struct Qdisc *sch, const struct nlattr *attr) 693 { 694 struct netem_sched_data *q = qdisc_priv(sch); 695 const struct tc_netem_reorder *r = nla_data(attr); 696 697 q->reorder = r->probability; 698 init_crandom(&q->reorder_cor, r->correlation); 699 } 700 701 static void get_corrupt(struct Qdisc *sch, const struct nlattr *attr) 702 { 703 struct netem_sched_data *q = qdisc_priv(sch); 704 const struct tc_netem_corrupt *r = nla_data(attr); 705 706 q->corrupt = r->probability; 707 init_crandom(&q->corrupt_cor, r->correlation); 708 } 709 710 static void get_rate(struct Qdisc *sch, const struct nlattr *attr) 711 { 712 struct netem_sched_data *q = qdisc_priv(sch); 713 const struct tc_netem_rate *r = nla_data(attr); 714 715 q->rate = r->rate; 716 q->packet_overhead = r->packet_overhead; 717 q->cell_size = r->cell_size; 718 if (q->cell_size) 719 q->cell_size_reciprocal = reciprocal_value(q->cell_size); 720 q->cell_overhead = r->cell_overhead; 721 } 722 723 static int get_loss_clg(struct Qdisc *sch, const struct nlattr *attr) 724 { 725 struct netem_sched_data *q = qdisc_priv(sch); 726 const struct nlattr *la; 727 int rem; 728 729 nla_for_each_nested(la, attr, rem) { 730 u16 type = nla_type(la); 731 732 switch(type) { 733 case NETEM_LOSS_GI: { 734 const struct tc_netem_gimodel *gi = nla_data(la); 735 736 if (nla_len(la) < sizeof(struct tc_netem_gimodel)) { 737 pr_info("netem: incorrect gi model size\n"); 738 return -EINVAL; 739 } 740 741 q->loss_model = CLG_4_STATES; 742 743 q->clg.state = 1; 744 q->clg.a1 = gi->p13; 745 q->clg.a2 = gi->p31; 746 q->clg.a3 = gi->p32; 747 q->clg.a4 = gi->p14; 748 q->clg.a5 = gi->p23; 749 break; 750 } 751 752 case NETEM_LOSS_GE: { 753 const struct tc_netem_gemodel *ge = nla_data(la); 754 755 if (nla_len(la) < sizeof(struct tc_netem_gemodel)) { 756 pr_info("netem: incorrect ge model size\n"); 757 return -EINVAL; 758 } 759 760 q->loss_model = CLG_GILB_ELL; 761 q->clg.state = 1; 762 q->clg.a1 = ge->p; 763 q->clg.a2 = ge->r; 764 q->clg.a3 = ge->h; 765 q->clg.a4 = ge->k1; 766 break; 767 } 768 769 default: 770 pr_info("netem: unknown loss type %u\n", type); 771 return -EINVAL; 772 } 773 } 774 775 return 0; 776 } 777 778 static const struct nla_policy netem_policy[TCA_NETEM_MAX + 1] = { 779 [TCA_NETEM_CORR] = { .len = sizeof(struct tc_netem_corr) }, 780 [TCA_NETEM_REORDER] = { .len = sizeof(struct tc_netem_reorder) }, 781 [TCA_NETEM_CORRUPT] = { .len = sizeof(struct tc_netem_corrupt) }, 782 [TCA_NETEM_RATE] = { .len = sizeof(struct tc_netem_rate) }, 783 [TCA_NETEM_LOSS] = { .type = NLA_NESTED }, 784 [TCA_NETEM_ECN] = { .type = NLA_U32 }, 785 }; 786 787 static int parse_attr(struct nlattr *tb[], int maxtype, struct nlattr *nla, 788 const struct nla_policy *policy, int len) 789 { 790 int nested_len = nla_len(nla) - NLA_ALIGN(len); 791 792 if (nested_len < 0) { 793 pr_info("netem: invalid attributes len %d\n", nested_len); 794 return -EINVAL; 795 } 796 797 if (nested_len >= nla_attr_size(0)) 798 return nla_parse(tb, maxtype, nla_data(nla) + NLA_ALIGN(len), 799 nested_len, policy); 800 801 memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1)); 802 return 0; 803 } 804 805 /* Parse netlink message to set options */ 806 static int netem_change(struct Qdisc *sch, struct nlattr *opt) 807 { 808 struct netem_sched_data *q = qdisc_priv(sch); 809 struct nlattr *tb[TCA_NETEM_MAX + 1]; 810 struct tc_netem_qopt *qopt; 811 int ret; 812 813 if (opt == NULL) 814 return -EINVAL; 815 816 qopt = nla_data(opt); 817 ret = parse_attr(tb, TCA_NETEM_MAX, opt, netem_policy, sizeof(*qopt)); 818 if (ret < 0) 819 return ret; 820 821 sch->limit = qopt->limit; 822 823 q->latency = qopt->latency; 824 q->jitter = qopt->jitter; 825 q->limit = qopt->limit; 826 q->gap = qopt->gap; 827 q->counter = 0; 828 q->loss = qopt->loss; 829 q->duplicate = qopt->duplicate; 830 831 /* for compatibility with earlier versions. 832 * if gap is set, need to assume 100% probability 833 */ 834 if (q->gap) 835 q->reorder = ~0; 836 837 if (tb[TCA_NETEM_CORR]) 838 get_correlation(sch, tb[TCA_NETEM_CORR]); 839 840 if (tb[TCA_NETEM_DELAY_DIST]) { 841 ret = get_dist_table(sch, tb[TCA_NETEM_DELAY_DIST]); 842 if (ret) 843 return ret; 844 } 845 846 if (tb[TCA_NETEM_REORDER]) 847 get_reorder(sch, tb[TCA_NETEM_REORDER]); 848 849 if (tb[TCA_NETEM_CORRUPT]) 850 get_corrupt(sch, tb[TCA_NETEM_CORRUPT]); 851 852 if (tb[TCA_NETEM_RATE]) 853 get_rate(sch, tb[TCA_NETEM_RATE]); 854 855 if (tb[TCA_NETEM_ECN]) 856 q->ecn = nla_get_u32(tb[TCA_NETEM_ECN]); 857 858 q->loss_model = CLG_RANDOM; 859 if (tb[TCA_NETEM_LOSS]) 860 ret = get_loss_clg(sch, tb[TCA_NETEM_LOSS]); 861 862 return ret; 863 } 864 865 static int netem_init(struct Qdisc *sch, struct nlattr *opt) 866 { 867 struct netem_sched_data *q = qdisc_priv(sch); 868 int ret; 869 870 if (!opt) 871 return -EINVAL; 872 873 qdisc_watchdog_init(&q->watchdog, sch); 874 875 q->loss_model = CLG_RANDOM; 876 ret = netem_change(sch, opt); 877 if (ret) 878 pr_info("netem: change failed\n"); 879 return ret; 880 } 881 882 static void netem_destroy(struct Qdisc *sch) 883 { 884 struct netem_sched_data *q = qdisc_priv(sch); 885 886 qdisc_watchdog_cancel(&q->watchdog); 887 if (q->qdisc) 888 qdisc_destroy(q->qdisc); 889 dist_free(q->delay_dist); 890 } 891 892 static int dump_loss_model(const struct netem_sched_data *q, 893 struct sk_buff *skb) 894 { 895 struct nlattr *nest; 896 897 nest = nla_nest_start(skb, TCA_NETEM_LOSS); 898 if (nest == NULL) 899 goto nla_put_failure; 900 901 switch (q->loss_model) { 902 case CLG_RANDOM: 903 /* legacy loss model */ 904 nla_nest_cancel(skb, nest); 905 return 0; /* no data */ 906 907 case CLG_4_STATES: { 908 struct tc_netem_gimodel gi = { 909 .p13 = q->clg.a1, 910 .p31 = q->clg.a2, 911 .p32 = q->clg.a3, 912 .p14 = q->clg.a4, 913 .p23 = q->clg.a5, 914 }; 915 916 if (nla_put(skb, NETEM_LOSS_GI, sizeof(gi), &gi)) 917 goto nla_put_failure; 918 break; 919 } 920 case CLG_GILB_ELL: { 921 struct tc_netem_gemodel ge = { 922 .p = q->clg.a1, 923 .r = q->clg.a2, 924 .h = q->clg.a3, 925 .k1 = q->clg.a4, 926 }; 927 928 if (nla_put(skb, NETEM_LOSS_GE, sizeof(ge), &ge)) 929 goto nla_put_failure; 930 break; 931 } 932 } 933 934 nla_nest_end(skb, nest); 935 return 0; 936 937 nla_put_failure: 938 nla_nest_cancel(skb, nest); 939 return -1; 940 } 941 942 static int netem_dump(struct Qdisc *sch, struct sk_buff *skb) 943 { 944 const struct netem_sched_data *q = qdisc_priv(sch); 945 struct nlattr *nla = (struct nlattr *) skb_tail_pointer(skb); 946 struct tc_netem_qopt qopt; 947 struct tc_netem_corr cor; 948 struct tc_netem_reorder reorder; 949 struct tc_netem_corrupt corrupt; 950 struct tc_netem_rate rate; 951 952 qopt.latency = q->latency; 953 qopt.jitter = q->jitter; 954 qopt.limit = q->limit; 955 qopt.loss = q->loss; 956 qopt.gap = q->gap; 957 qopt.duplicate = q->duplicate; 958 if (nla_put(skb, TCA_OPTIONS, sizeof(qopt), &qopt)) 959 goto nla_put_failure; 960 961 cor.delay_corr = q->delay_cor.rho; 962 cor.loss_corr = q->loss_cor.rho; 963 cor.dup_corr = q->dup_cor.rho; 964 if (nla_put(skb, TCA_NETEM_CORR, sizeof(cor), &cor)) 965 goto nla_put_failure; 966 967 reorder.probability = q->reorder; 968 reorder.correlation = q->reorder_cor.rho; 969 if (nla_put(skb, TCA_NETEM_REORDER, sizeof(reorder), &reorder)) 970 goto nla_put_failure; 971 972 corrupt.probability = q->corrupt; 973 corrupt.correlation = q->corrupt_cor.rho; 974 if (nla_put(skb, TCA_NETEM_CORRUPT, sizeof(corrupt), &corrupt)) 975 goto nla_put_failure; 976 977 rate.rate = q->rate; 978 rate.packet_overhead = q->packet_overhead; 979 rate.cell_size = q->cell_size; 980 rate.cell_overhead = q->cell_overhead; 981 if (nla_put(skb, TCA_NETEM_RATE, sizeof(rate), &rate)) 982 goto nla_put_failure; 983 984 if (q->ecn && nla_put_u32(skb, TCA_NETEM_ECN, q->ecn)) 985 goto nla_put_failure; 986 987 if (dump_loss_model(q, skb) != 0) 988 goto nla_put_failure; 989 990 return nla_nest_end(skb, nla); 991 992 nla_put_failure: 993 nlmsg_trim(skb, nla); 994 return -1; 995 } 996 997 static int netem_dump_class(struct Qdisc *sch, unsigned long cl, 998 struct sk_buff *skb, struct tcmsg *tcm) 999 { 1000 struct netem_sched_data *q = qdisc_priv(sch); 1001 1002 if (cl != 1 || !q->qdisc) /* only one class */ 1003 return -ENOENT; 1004 1005 tcm->tcm_handle |= TC_H_MIN(1); 1006 tcm->tcm_info = q->qdisc->handle; 1007 1008 return 0; 1009 } 1010 1011 static int netem_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, 1012 struct Qdisc **old) 1013 { 1014 struct netem_sched_data *q = qdisc_priv(sch); 1015 1016 sch_tree_lock(sch); 1017 *old = q->qdisc; 1018 q->qdisc = new; 1019 if (*old) { 1020 qdisc_tree_decrease_qlen(*old, (*old)->q.qlen); 1021 qdisc_reset(*old); 1022 } 1023 sch_tree_unlock(sch); 1024 1025 return 0; 1026 } 1027 1028 static struct Qdisc *netem_leaf(struct Qdisc *sch, unsigned long arg) 1029 { 1030 struct netem_sched_data *q = qdisc_priv(sch); 1031 return q->qdisc; 1032 } 1033 1034 static unsigned long netem_get(struct Qdisc *sch, u32 classid) 1035 { 1036 return 1; 1037 } 1038 1039 static void netem_put(struct Qdisc *sch, unsigned long arg) 1040 { 1041 } 1042 1043 static void netem_walk(struct Qdisc *sch, struct qdisc_walker *walker) 1044 { 1045 if (!walker->stop) { 1046 if (walker->count >= walker->skip) 1047 if (walker->fn(sch, 1, walker) < 0) { 1048 walker->stop = 1; 1049 return; 1050 } 1051 walker->count++; 1052 } 1053 } 1054 1055 static const struct Qdisc_class_ops netem_class_ops = { 1056 .graft = netem_graft, 1057 .leaf = netem_leaf, 1058 .get = netem_get, 1059 .put = netem_put, 1060 .walk = netem_walk, 1061 .dump = netem_dump_class, 1062 }; 1063 1064 static struct Qdisc_ops netem_qdisc_ops __read_mostly = { 1065 .id = "netem", 1066 .cl_ops = &netem_class_ops, 1067 .priv_size = sizeof(struct netem_sched_data), 1068 .enqueue = netem_enqueue, 1069 .dequeue = netem_dequeue, 1070 .peek = qdisc_peek_dequeued, 1071 .drop = netem_drop, 1072 .init = netem_init, 1073 .reset = netem_reset, 1074 .destroy = netem_destroy, 1075 .change = netem_change, 1076 .dump = netem_dump, 1077 .owner = THIS_MODULE, 1078 }; 1079 1080 1081 static int __init netem_module_init(void) 1082 { 1083 pr_info("netem: version " VERSION "\n"); 1084 return register_qdisc(&netem_qdisc_ops); 1085 } 1086 static void __exit netem_module_exit(void) 1087 { 1088 unregister_qdisc(&netem_qdisc_ops); 1089 } 1090 module_init(netem_module_init) 1091 module_exit(netem_module_exit) 1092 MODULE_LICENSE("GPL"); 1093