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 u64 rate; 92 s32 packet_overhead; 93 u32 cell_size; 94 struct reciprocal_value 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 enum { 114 TX_IN_GAP_PERIOD = 1, 115 TX_IN_BURST_PERIOD, 116 LOST_IN_GAP_PERIOD, 117 LOST_IN_BURST_PERIOD, 118 } _4_state_model; 119 120 enum { 121 GOOD_STATE = 1, 122 BAD_STATE, 123 } GE_state_model; 124 125 /* Correlated Loss Generation models */ 126 struct clgstate { 127 /* state of the Markov chain */ 128 u8 state; 129 130 /* 4-states and Gilbert-Elliot models */ 131 u32 a1; /* p13 for 4-states or p for GE */ 132 u32 a2; /* p31 for 4-states or r for GE */ 133 u32 a3; /* p32 for 4-states or h for GE */ 134 u32 a4; /* p14 for 4-states or 1-k for GE */ 135 u32 a5; /* p23 used only in 4-states */ 136 } clg; 137 138 }; 139 140 /* Time stamp put into socket buffer control block 141 * Only valid when skbs are in our internal t(ime)fifo queue. 142 * 143 * As skb->rbnode uses same storage than skb->next, skb->prev and skb->tstamp, 144 * and skb->next & skb->prev are scratch space for a qdisc, 145 * we save skb->tstamp value in skb->cb[] before destroying it. 146 */ 147 struct netem_skb_cb { 148 psched_time_t time_to_send; 149 ktime_t tstamp_save; 150 }; 151 152 153 static struct sk_buff *netem_rb_to_skb(struct rb_node *rb) 154 { 155 return container_of(rb, struct sk_buff, rbnode); 156 } 157 158 static inline struct netem_skb_cb *netem_skb_cb(struct sk_buff *skb) 159 { 160 /* we assume we can use skb next/prev/tstamp as storage for rb_node */ 161 qdisc_cb_private_validate(skb, sizeof(struct netem_skb_cb)); 162 return (struct netem_skb_cb *)qdisc_skb_cb(skb)->data; 163 } 164 165 /* init_crandom - initialize correlated random number generator 166 * Use entropy source for initial seed. 167 */ 168 static void init_crandom(struct crndstate *state, unsigned long rho) 169 { 170 state->rho = rho; 171 state->last = prandom_u32(); 172 } 173 174 /* get_crandom - correlated random number generator 175 * Next number depends on last value. 176 * rho is scaled to avoid floating point. 177 */ 178 static u32 get_crandom(struct crndstate *state) 179 { 180 u64 value, rho; 181 unsigned long answer; 182 183 if (state->rho == 0) /* no correlation */ 184 return prandom_u32(); 185 186 value = prandom_u32(); 187 rho = (u64)state->rho + 1; 188 answer = (value * ((1ull<<32) - rho) + state->last * rho) >> 32; 189 state->last = answer; 190 return answer; 191 } 192 193 /* loss_4state - 4-state model loss generator 194 * Generates losses according to the 4-state Markov chain adopted in 195 * the GI (General and Intuitive) loss model. 196 */ 197 static bool loss_4state(struct netem_sched_data *q) 198 { 199 struct clgstate *clg = &q->clg; 200 u32 rnd = prandom_u32(); 201 202 /* 203 * Makes a comparison between rnd and the transition 204 * probabilities outgoing from the current state, then decides the 205 * next state and if the next packet has to be transmitted or lost. 206 * The four states correspond to: 207 * TX_IN_GAP_PERIOD => successfully transmitted packets within a gap period 208 * LOST_IN_BURST_PERIOD => isolated losses within a gap period 209 * LOST_IN_GAP_PERIOD => lost packets within a burst period 210 * TX_IN_GAP_PERIOD => successfully transmitted packets within a burst period 211 */ 212 switch (clg->state) { 213 case TX_IN_GAP_PERIOD: 214 if (rnd < clg->a4) { 215 clg->state = LOST_IN_BURST_PERIOD; 216 return true; 217 } else if (clg->a4 < rnd && rnd < clg->a1 + clg->a4) { 218 clg->state = LOST_IN_GAP_PERIOD; 219 return true; 220 } else if (clg->a1 + clg->a4 < rnd) { 221 clg->state = TX_IN_GAP_PERIOD; 222 } 223 224 break; 225 case TX_IN_BURST_PERIOD: 226 if (rnd < clg->a5) { 227 clg->state = LOST_IN_GAP_PERIOD; 228 return true; 229 } else { 230 clg->state = TX_IN_BURST_PERIOD; 231 } 232 233 break; 234 case LOST_IN_GAP_PERIOD: 235 if (rnd < clg->a3) 236 clg->state = TX_IN_BURST_PERIOD; 237 else if (clg->a3 < rnd && rnd < clg->a2 + clg->a3) { 238 clg->state = TX_IN_GAP_PERIOD; 239 } else if (clg->a2 + clg->a3 < rnd) { 240 clg->state = LOST_IN_GAP_PERIOD; 241 return true; 242 } 243 break; 244 case LOST_IN_BURST_PERIOD: 245 clg->state = TX_IN_GAP_PERIOD; 246 break; 247 } 248 249 return false; 250 } 251 252 /* loss_gilb_ell - Gilbert-Elliot model loss generator 253 * Generates losses according to the Gilbert-Elliot loss model or 254 * its special cases (Gilbert or Simple Gilbert) 255 * 256 * Makes a comparison between random number and the transition 257 * probabilities outgoing from the current state, then decides the 258 * next state. A second random number is extracted and the comparison 259 * with the loss probability of the current state decides if the next 260 * packet will be transmitted or lost. 261 */ 262 static bool loss_gilb_ell(struct netem_sched_data *q) 263 { 264 struct clgstate *clg = &q->clg; 265 266 switch (clg->state) { 267 case GOOD_STATE: 268 if (prandom_u32() < clg->a1) 269 clg->state = BAD_STATE; 270 if (prandom_u32() < clg->a4) 271 return true; 272 break; 273 case BAD_STATE: 274 if (prandom_u32() < clg->a2) 275 clg->state = GOOD_STATE; 276 if (prandom_u32() > clg->a3) 277 return true; 278 } 279 280 return false; 281 } 282 283 static bool loss_event(struct netem_sched_data *q) 284 { 285 switch (q->loss_model) { 286 case CLG_RANDOM: 287 /* Random packet drop 0 => none, ~0 => all */ 288 return q->loss && q->loss >= get_crandom(&q->loss_cor); 289 290 case CLG_4_STATES: 291 /* 4state loss model algorithm (used also for GI model) 292 * Extracts a value from the markov 4 state loss generator, 293 * if it is 1 drops a packet and if needed writes the event in 294 * the kernel logs 295 */ 296 return loss_4state(q); 297 298 case CLG_GILB_ELL: 299 /* Gilbert-Elliot loss model algorithm 300 * Extracts a value from the Gilbert-Elliot loss generator, 301 * if it is 1 drops a packet and if needed writes the event in 302 * the kernel logs 303 */ 304 return loss_gilb_ell(q); 305 } 306 307 return false; /* not reached */ 308 } 309 310 311 /* tabledist - return a pseudo-randomly distributed value with mean mu and 312 * std deviation sigma. Uses table lookup to approximate the desired 313 * distribution, and a uniformly-distributed pseudo-random source. 314 */ 315 static psched_tdiff_t tabledist(psched_tdiff_t mu, psched_tdiff_t sigma, 316 struct crndstate *state, 317 const struct disttable *dist) 318 { 319 psched_tdiff_t x; 320 long t; 321 u32 rnd; 322 323 if (sigma == 0) 324 return mu; 325 326 rnd = get_crandom(state); 327 328 /* default uniform distribution */ 329 if (dist == NULL) 330 return (rnd % (2*sigma)) - sigma + mu; 331 332 t = dist->table[rnd % dist->size]; 333 x = (sigma % NETEM_DIST_SCALE) * t; 334 if (x >= 0) 335 x += NETEM_DIST_SCALE/2; 336 else 337 x -= NETEM_DIST_SCALE/2; 338 339 return x / NETEM_DIST_SCALE + (sigma / NETEM_DIST_SCALE) * t + mu; 340 } 341 342 static psched_time_t packet_len_2_sched_time(unsigned int len, struct netem_sched_data *q) 343 { 344 u64 ticks; 345 346 len += q->packet_overhead; 347 348 if (q->cell_size) { 349 u32 cells = reciprocal_divide(len, q->cell_size_reciprocal); 350 351 if (len > cells * q->cell_size) /* extra cell needed for remainder */ 352 cells++; 353 len = cells * (q->cell_size + q->cell_overhead); 354 } 355 356 ticks = (u64)len * NSEC_PER_SEC; 357 358 do_div(ticks, q->rate); 359 return PSCHED_NS2TICKS(ticks); 360 } 361 362 static void tfifo_reset(struct Qdisc *sch) 363 { 364 struct netem_sched_data *q = qdisc_priv(sch); 365 struct rb_node *p; 366 367 while ((p = rb_first(&q->t_root))) { 368 struct sk_buff *skb = netem_rb_to_skb(p); 369 370 rb_erase(p, &q->t_root); 371 skb->next = NULL; 372 skb->prev = NULL; 373 kfree_skb(skb); 374 } 375 } 376 377 static void tfifo_enqueue(struct sk_buff *nskb, struct Qdisc *sch) 378 { 379 struct netem_sched_data *q = qdisc_priv(sch); 380 psched_time_t tnext = netem_skb_cb(nskb)->time_to_send; 381 struct rb_node **p = &q->t_root.rb_node, *parent = NULL; 382 383 while (*p) { 384 struct sk_buff *skb; 385 386 parent = *p; 387 skb = netem_rb_to_skb(parent); 388 if (tnext >= netem_skb_cb(skb)->time_to_send) 389 p = &parent->rb_right; 390 else 391 p = &parent->rb_left; 392 } 393 rb_link_node(&nskb->rbnode, parent, p); 394 rb_insert_color(&nskb->rbnode, &q->t_root); 395 sch->q.qlen++; 396 } 397 398 /* 399 * Insert one skb into qdisc. 400 * Note: parent depends on return value to account for queue length. 401 * NET_XMIT_DROP: queue length didn't change. 402 * NET_XMIT_SUCCESS: one skb was queued. 403 */ 404 static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch) 405 { 406 struct netem_sched_data *q = qdisc_priv(sch); 407 /* We don't fill cb now as skb_unshare() may invalidate it */ 408 struct netem_skb_cb *cb; 409 struct sk_buff *skb2; 410 int count = 1; 411 412 /* Random duplication */ 413 if (q->duplicate && q->duplicate >= get_crandom(&q->dup_cor)) 414 ++count; 415 416 /* Drop packet? */ 417 if (loss_event(q)) { 418 if (q->ecn && INET_ECN_set_ce(skb)) 419 qdisc_qstats_drop(sch); /* mark packet */ 420 else 421 --count; 422 } 423 if (count == 0) { 424 qdisc_qstats_drop(sch); 425 kfree_skb(skb); 426 return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; 427 } 428 429 /* If a delay is expected, orphan the skb. (orphaning usually takes 430 * place at TX completion time, so _before_ the link transit delay) 431 */ 432 if (q->latency || q->jitter) 433 skb_orphan_partial(skb); 434 435 /* 436 * If we need to duplicate packet, then re-insert at top of the 437 * qdisc tree, since parent queuer expects that only one 438 * skb will be queued. 439 */ 440 if (count > 1 && (skb2 = skb_clone(skb, GFP_ATOMIC)) != NULL) { 441 struct Qdisc *rootq = qdisc_root(sch); 442 u32 dupsave = q->duplicate; /* prevent duplicating a dup... */ 443 444 q->duplicate = 0; 445 rootq->enqueue(skb2, rootq); 446 q->duplicate = dupsave; 447 } 448 449 /* 450 * Randomized packet corruption. 451 * Make copy if needed since we are modifying 452 * If packet is going to be hardware checksummed, then 453 * do it now in software before we mangle it. 454 */ 455 if (q->corrupt && q->corrupt >= get_crandom(&q->corrupt_cor)) { 456 if (!(skb = skb_unshare(skb, GFP_ATOMIC)) || 457 (skb->ip_summed == CHECKSUM_PARTIAL && 458 skb_checksum_help(skb))) 459 return qdisc_drop(skb, sch); 460 461 skb->data[prandom_u32() % skb_headlen(skb)] ^= 462 1<<(prandom_u32() % 8); 463 } 464 465 if (unlikely(skb_queue_len(&sch->q) >= sch->limit)) 466 return qdisc_reshape_fail(skb, sch); 467 468 qdisc_qstats_backlog_inc(sch, skb); 469 470 cb = netem_skb_cb(skb); 471 if (q->gap == 0 || /* not doing reordering */ 472 q->counter < q->gap - 1 || /* inside last reordering gap */ 473 q->reorder < get_crandom(&q->reorder_cor)) { 474 psched_time_t now; 475 psched_tdiff_t delay; 476 477 delay = tabledist(q->latency, q->jitter, 478 &q->delay_cor, q->delay_dist); 479 480 now = psched_get_time(); 481 482 if (q->rate) { 483 struct sk_buff *last; 484 485 if (!skb_queue_empty(&sch->q)) 486 last = skb_peek_tail(&sch->q); 487 else 488 last = netem_rb_to_skb(rb_last(&q->t_root)); 489 if (last) { 490 /* 491 * Last packet in queue is reference point (now), 492 * calculate this time bonus and subtract 493 * from delay. 494 */ 495 delay -= netem_skb_cb(last)->time_to_send - now; 496 delay = max_t(psched_tdiff_t, 0, delay); 497 now = netem_skb_cb(last)->time_to_send; 498 } 499 500 delay += packet_len_2_sched_time(qdisc_pkt_len(skb), q); 501 } 502 503 cb->time_to_send = now + delay; 504 cb->tstamp_save = skb->tstamp; 505 ++q->counter; 506 tfifo_enqueue(skb, sch); 507 } else { 508 /* 509 * Do re-ordering by putting one out of N packets at the front 510 * of the queue. 511 */ 512 cb->time_to_send = psched_get_time(); 513 q->counter = 0; 514 515 __skb_queue_head(&sch->q, skb); 516 sch->qstats.requeues++; 517 } 518 519 return NET_XMIT_SUCCESS; 520 } 521 522 static unsigned int netem_drop(struct Qdisc *sch) 523 { 524 struct netem_sched_data *q = qdisc_priv(sch); 525 unsigned int len; 526 527 len = qdisc_queue_drop(sch); 528 529 if (!len) { 530 struct rb_node *p = rb_first(&q->t_root); 531 532 if (p) { 533 struct sk_buff *skb = netem_rb_to_skb(p); 534 535 rb_erase(p, &q->t_root); 536 sch->q.qlen--; 537 skb->next = NULL; 538 skb->prev = NULL; 539 qdisc_qstats_backlog_dec(sch, skb); 540 kfree_skb(skb); 541 } 542 } 543 if (!len && q->qdisc && q->qdisc->ops->drop) 544 len = q->qdisc->ops->drop(q->qdisc); 545 if (len) 546 qdisc_qstats_drop(sch); 547 548 return len; 549 } 550 551 static struct sk_buff *netem_dequeue(struct Qdisc *sch) 552 { 553 struct netem_sched_data *q = qdisc_priv(sch); 554 struct sk_buff *skb; 555 struct rb_node *p; 556 557 if (qdisc_is_throttled(sch)) 558 return NULL; 559 560 tfifo_dequeue: 561 skb = __skb_dequeue(&sch->q); 562 if (skb) { 563 qdisc_qstats_backlog_dec(sch, skb); 564 deliver: 565 qdisc_unthrottled(sch); 566 qdisc_bstats_update(sch, skb); 567 return skb; 568 } 569 p = rb_first(&q->t_root); 570 if (p) { 571 psched_time_t time_to_send; 572 573 skb = netem_rb_to_skb(p); 574 575 /* if more time remaining? */ 576 time_to_send = netem_skb_cb(skb)->time_to_send; 577 if (time_to_send <= psched_get_time()) { 578 rb_erase(p, &q->t_root); 579 580 sch->q.qlen--; 581 qdisc_qstats_backlog_dec(sch, skb); 582 skb->next = NULL; 583 skb->prev = NULL; 584 skb->tstamp = netem_skb_cb(skb)->tstamp_save; 585 586 #ifdef CONFIG_NET_CLS_ACT 587 /* 588 * If it's at ingress let's pretend the delay is 589 * from the network (tstamp will be updated). 590 */ 591 if (G_TC_FROM(skb->tc_verd) & AT_INGRESS) 592 skb->tstamp.tv64 = 0; 593 #endif 594 595 if (q->qdisc) { 596 int err = qdisc_enqueue(skb, q->qdisc); 597 598 if (unlikely(err != NET_XMIT_SUCCESS)) { 599 if (net_xmit_drop_count(err)) { 600 qdisc_qstats_drop(sch); 601 qdisc_tree_reduce_backlog(sch, 1, 602 qdisc_pkt_len(skb)); 603 } 604 } 605 goto tfifo_dequeue; 606 } 607 goto deliver; 608 } 609 610 if (q->qdisc) { 611 skb = q->qdisc->ops->dequeue(q->qdisc); 612 if (skb) 613 goto deliver; 614 } 615 qdisc_watchdog_schedule(&q->watchdog, time_to_send); 616 } 617 618 if (q->qdisc) { 619 skb = q->qdisc->ops->dequeue(q->qdisc); 620 if (skb) 621 goto deliver; 622 } 623 return NULL; 624 } 625 626 static void netem_reset(struct Qdisc *sch) 627 { 628 struct netem_sched_data *q = qdisc_priv(sch); 629 630 qdisc_reset_queue(sch); 631 tfifo_reset(sch); 632 if (q->qdisc) 633 qdisc_reset(q->qdisc); 634 qdisc_watchdog_cancel(&q->watchdog); 635 } 636 637 static void dist_free(struct disttable *d) 638 { 639 kvfree(d); 640 } 641 642 /* 643 * Distribution data is a variable size payload containing 644 * signed 16 bit values. 645 */ 646 static int get_dist_table(struct Qdisc *sch, const struct nlattr *attr) 647 { 648 struct netem_sched_data *q = qdisc_priv(sch); 649 size_t n = nla_len(attr)/sizeof(__s16); 650 const __s16 *data = nla_data(attr); 651 spinlock_t *root_lock; 652 struct disttable *d; 653 int i; 654 size_t s; 655 656 if (n > NETEM_DIST_MAX) 657 return -EINVAL; 658 659 s = sizeof(struct disttable) + n * sizeof(s16); 660 d = kmalloc(s, GFP_KERNEL | __GFP_NOWARN); 661 if (!d) 662 d = vmalloc(s); 663 if (!d) 664 return -ENOMEM; 665 666 d->size = n; 667 for (i = 0; i < n; i++) 668 d->table[i] = data[i]; 669 670 root_lock = qdisc_root_sleeping_lock(sch); 671 672 spin_lock_bh(root_lock); 673 swap(q->delay_dist, d); 674 spin_unlock_bh(root_lock); 675 676 dist_free(d); 677 return 0; 678 } 679 680 static void get_correlation(struct netem_sched_data *q, const struct nlattr *attr) 681 { 682 const struct tc_netem_corr *c = nla_data(attr); 683 684 init_crandom(&q->delay_cor, c->delay_corr); 685 init_crandom(&q->loss_cor, c->loss_corr); 686 init_crandom(&q->dup_cor, c->dup_corr); 687 } 688 689 static void get_reorder(struct netem_sched_data *q, const struct nlattr *attr) 690 { 691 const struct tc_netem_reorder *r = nla_data(attr); 692 693 q->reorder = r->probability; 694 init_crandom(&q->reorder_cor, r->correlation); 695 } 696 697 static void get_corrupt(struct netem_sched_data *q, const struct nlattr *attr) 698 { 699 const struct tc_netem_corrupt *r = nla_data(attr); 700 701 q->corrupt = r->probability; 702 init_crandom(&q->corrupt_cor, r->correlation); 703 } 704 705 static void get_rate(struct netem_sched_data *q, const struct nlattr *attr) 706 { 707 const struct tc_netem_rate *r = nla_data(attr); 708 709 q->rate = r->rate; 710 q->packet_overhead = r->packet_overhead; 711 q->cell_size = r->cell_size; 712 q->cell_overhead = r->cell_overhead; 713 if (q->cell_size) 714 q->cell_size_reciprocal = reciprocal_value(q->cell_size); 715 else 716 q->cell_size_reciprocal = (struct reciprocal_value) { 0 }; 717 } 718 719 static int get_loss_clg(struct netem_sched_data *q, const struct nlattr *attr) 720 { 721 const struct nlattr *la; 722 int rem; 723 724 nla_for_each_nested(la, attr, rem) { 725 u16 type = nla_type(la); 726 727 switch (type) { 728 case NETEM_LOSS_GI: { 729 const struct tc_netem_gimodel *gi = nla_data(la); 730 731 if (nla_len(la) < sizeof(struct tc_netem_gimodel)) { 732 pr_info("netem: incorrect gi model size\n"); 733 return -EINVAL; 734 } 735 736 q->loss_model = CLG_4_STATES; 737 738 q->clg.state = TX_IN_GAP_PERIOD; 739 q->clg.a1 = gi->p13; 740 q->clg.a2 = gi->p31; 741 q->clg.a3 = gi->p32; 742 q->clg.a4 = gi->p14; 743 q->clg.a5 = gi->p23; 744 break; 745 } 746 747 case NETEM_LOSS_GE: { 748 const struct tc_netem_gemodel *ge = nla_data(la); 749 750 if (nla_len(la) < sizeof(struct tc_netem_gemodel)) { 751 pr_info("netem: incorrect ge model size\n"); 752 return -EINVAL; 753 } 754 755 q->loss_model = CLG_GILB_ELL; 756 q->clg.state = GOOD_STATE; 757 q->clg.a1 = ge->p; 758 q->clg.a2 = ge->r; 759 q->clg.a3 = ge->h; 760 q->clg.a4 = ge->k1; 761 break; 762 } 763 764 default: 765 pr_info("netem: unknown loss type %u\n", type); 766 return -EINVAL; 767 } 768 } 769 770 return 0; 771 } 772 773 static const struct nla_policy netem_policy[TCA_NETEM_MAX + 1] = { 774 [TCA_NETEM_CORR] = { .len = sizeof(struct tc_netem_corr) }, 775 [TCA_NETEM_REORDER] = { .len = sizeof(struct tc_netem_reorder) }, 776 [TCA_NETEM_CORRUPT] = { .len = sizeof(struct tc_netem_corrupt) }, 777 [TCA_NETEM_RATE] = { .len = sizeof(struct tc_netem_rate) }, 778 [TCA_NETEM_LOSS] = { .type = NLA_NESTED }, 779 [TCA_NETEM_ECN] = { .type = NLA_U32 }, 780 [TCA_NETEM_RATE64] = { .type = NLA_U64 }, 781 }; 782 783 static int parse_attr(struct nlattr *tb[], int maxtype, struct nlattr *nla, 784 const struct nla_policy *policy, int len) 785 { 786 int nested_len = nla_len(nla) - NLA_ALIGN(len); 787 788 if (nested_len < 0) { 789 pr_info("netem: invalid attributes len %d\n", nested_len); 790 return -EINVAL; 791 } 792 793 if (nested_len >= nla_attr_size(0)) 794 return nla_parse(tb, maxtype, nla_data(nla) + NLA_ALIGN(len), 795 nested_len, policy); 796 797 memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1)); 798 return 0; 799 } 800 801 /* Parse netlink message to set options */ 802 static int netem_change(struct Qdisc *sch, struct nlattr *opt) 803 { 804 struct netem_sched_data *q = qdisc_priv(sch); 805 struct nlattr *tb[TCA_NETEM_MAX + 1]; 806 struct tc_netem_qopt *qopt; 807 struct clgstate old_clg; 808 int old_loss_model = CLG_RANDOM; 809 int ret; 810 811 if (opt == NULL) 812 return -EINVAL; 813 814 qopt = nla_data(opt); 815 ret = parse_attr(tb, TCA_NETEM_MAX, opt, netem_policy, sizeof(*qopt)); 816 if (ret < 0) 817 return ret; 818 819 /* backup q->clg and q->loss_model */ 820 old_clg = q->clg; 821 old_loss_model = q->loss_model; 822 823 if (tb[TCA_NETEM_LOSS]) { 824 ret = get_loss_clg(q, tb[TCA_NETEM_LOSS]); 825 if (ret) { 826 q->loss_model = old_loss_model; 827 return ret; 828 } 829 } else { 830 q->loss_model = CLG_RANDOM; 831 } 832 833 if (tb[TCA_NETEM_DELAY_DIST]) { 834 ret = get_dist_table(sch, tb[TCA_NETEM_DELAY_DIST]); 835 if (ret) { 836 /* recover clg and loss_model, in case of 837 * q->clg and q->loss_model were modified 838 * in get_loss_clg() 839 */ 840 q->clg = old_clg; 841 q->loss_model = old_loss_model; 842 return ret; 843 } 844 } 845 846 sch->limit = qopt->limit; 847 848 q->latency = qopt->latency; 849 q->jitter = qopt->jitter; 850 q->limit = qopt->limit; 851 q->gap = qopt->gap; 852 q->counter = 0; 853 q->loss = qopt->loss; 854 q->duplicate = qopt->duplicate; 855 856 /* for compatibility with earlier versions. 857 * if gap is set, need to assume 100% probability 858 */ 859 if (q->gap) 860 q->reorder = ~0; 861 862 if (tb[TCA_NETEM_CORR]) 863 get_correlation(q, tb[TCA_NETEM_CORR]); 864 865 if (tb[TCA_NETEM_REORDER]) 866 get_reorder(q, tb[TCA_NETEM_REORDER]); 867 868 if (tb[TCA_NETEM_CORRUPT]) 869 get_corrupt(q, tb[TCA_NETEM_CORRUPT]); 870 871 if (tb[TCA_NETEM_RATE]) 872 get_rate(q, tb[TCA_NETEM_RATE]); 873 874 if (tb[TCA_NETEM_RATE64]) 875 q->rate = max_t(u64, q->rate, 876 nla_get_u64(tb[TCA_NETEM_RATE64])); 877 878 if (tb[TCA_NETEM_ECN]) 879 q->ecn = nla_get_u32(tb[TCA_NETEM_ECN]); 880 881 return ret; 882 } 883 884 static int netem_init(struct Qdisc *sch, struct nlattr *opt) 885 { 886 struct netem_sched_data *q = qdisc_priv(sch); 887 int ret; 888 889 if (!opt) 890 return -EINVAL; 891 892 qdisc_watchdog_init(&q->watchdog, sch); 893 894 q->loss_model = CLG_RANDOM; 895 ret = netem_change(sch, opt); 896 if (ret) 897 pr_info("netem: change failed\n"); 898 return ret; 899 } 900 901 static void netem_destroy(struct Qdisc *sch) 902 { 903 struct netem_sched_data *q = qdisc_priv(sch); 904 905 qdisc_watchdog_cancel(&q->watchdog); 906 if (q->qdisc) 907 qdisc_destroy(q->qdisc); 908 dist_free(q->delay_dist); 909 } 910 911 static int dump_loss_model(const struct netem_sched_data *q, 912 struct sk_buff *skb) 913 { 914 struct nlattr *nest; 915 916 nest = nla_nest_start(skb, TCA_NETEM_LOSS); 917 if (nest == NULL) 918 goto nla_put_failure; 919 920 switch (q->loss_model) { 921 case CLG_RANDOM: 922 /* legacy loss model */ 923 nla_nest_cancel(skb, nest); 924 return 0; /* no data */ 925 926 case CLG_4_STATES: { 927 struct tc_netem_gimodel gi = { 928 .p13 = q->clg.a1, 929 .p31 = q->clg.a2, 930 .p32 = q->clg.a3, 931 .p14 = q->clg.a4, 932 .p23 = q->clg.a5, 933 }; 934 935 if (nla_put(skb, NETEM_LOSS_GI, sizeof(gi), &gi)) 936 goto nla_put_failure; 937 break; 938 } 939 case CLG_GILB_ELL: { 940 struct tc_netem_gemodel ge = { 941 .p = q->clg.a1, 942 .r = q->clg.a2, 943 .h = q->clg.a3, 944 .k1 = q->clg.a4, 945 }; 946 947 if (nla_put(skb, NETEM_LOSS_GE, sizeof(ge), &ge)) 948 goto nla_put_failure; 949 break; 950 } 951 } 952 953 nla_nest_end(skb, nest); 954 return 0; 955 956 nla_put_failure: 957 nla_nest_cancel(skb, nest); 958 return -1; 959 } 960 961 static int netem_dump(struct Qdisc *sch, struct sk_buff *skb) 962 { 963 const struct netem_sched_data *q = qdisc_priv(sch); 964 struct nlattr *nla = (struct nlattr *) skb_tail_pointer(skb); 965 struct tc_netem_qopt qopt; 966 struct tc_netem_corr cor; 967 struct tc_netem_reorder reorder; 968 struct tc_netem_corrupt corrupt; 969 struct tc_netem_rate rate; 970 971 qopt.latency = q->latency; 972 qopt.jitter = q->jitter; 973 qopt.limit = q->limit; 974 qopt.loss = q->loss; 975 qopt.gap = q->gap; 976 qopt.duplicate = q->duplicate; 977 if (nla_put(skb, TCA_OPTIONS, sizeof(qopt), &qopt)) 978 goto nla_put_failure; 979 980 cor.delay_corr = q->delay_cor.rho; 981 cor.loss_corr = q->loss_cor.rho; 982 cor.dup_corr = q->dup_cor.rho; 983 if (nla_put(skb, TCA_NETEM_CORR, sizeof(cor), &cor)) 984 goto nla_put_failure; 985 986 reorder.probability = q->reorder; 987 reorder.correlation = q->reorder_cor.rho; 988 if (nla_put(skb, TCA_NETEM_REORDER, sizeof(reorder), &reorder)) 989 goto nla_put_failure; 990 991 corrupt.probability = q->corrupt; 992 corrupt.correlation = q->corrupt_cor.rho; 993 if (nla_put(skb, TCA_NETEM_CORRUPT, sizeof(corrupt), &corrupt)) 994 goto nla_put_failure; 995 996 if (q->rate >= (1ULL << 32)) { 997 if (nla_put_u64(skb, TCA_NETEM_RATE64, q->rate)) 998 goto nla_put_failure; 999 rate.rate = ~0U; 1000 } else { 1001 rate.rate = q->rate; 1002 } 1003 rate.packet_overhead = q->packet_overhead; 1004 rate.cell_size = q->cell_size; 1005 rate.cell_overhead = q->cell_overhead; 1006 if (nla_put(skb, TCA_NETEM_RATE, sizeof(rate), &rate)) 1007 goto nla_put_failure; 1008 1009 if (q->ecn && nla_put_u32(skb, TCA_NETEM_ECN, q->ecn)) 1010 goto nla_put_failure; 1011 1012 if (dump_loss_model(q, skb) != 0) 1013 goto nla_put_failure; 1014 1015 return nla_nest_end(skb, nla); 1016 1017 nla_put_failure: 1018 nlmsg_trim(skb, nla); 1019 return -1; 1020 } 1021 1022 static int netem_dump_class(struct Qdisc *sch, unsigned long cl, 1023 struct sk_buff *skb, struct tcmsg *tcm) 1024 { 1025 struct netem_sched_data *q = qdisc_priv(sch); 1026 1027 if (cl != 1 || !q->qdisc) /* only one class */ 1028 return -ENOENT; 1029 1030 tcm->tcm_handle |= TC_H_MIN(1); 1031 tcm->tcm_info = q->qdisc->handle; 1032 1033 return 0; 1034 } 1035 1036 static int netem_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, 1037 struct Qdisc **old) 1038 { 1039 struct netem_sched_data *q = qdisc_priv(sch); 1040 1041 *old = qdisc_replace(sch, new, &q->qdisc); 1042 return 0; 1043 } 1044 1045 static struct Qdisc *netem_leaf(struct Qdisc *sch, unsigned long arg) 1046 { 1047 struct netem_sched_data *q = qdisc_priv(sch); 1048 return q->qdisc; 1049 } 1050 1051 static unsigned long netem_get(struct Qdisc *sch, u32 classid) 1052 { 1053 return 1; 1054 } 1055 1056 static void netem_put(struct Qdisc *sch, unsigned long arg) 1057 { 1058 } 1059 1060 static void netem_walk(struct Qdisc *sch, struct qdisc_walker *walker) 1061 { 1062 if (!walker->stop) { 1063 if (walker->count >= walker->skip) 1064 if (walker->fn(sch, 1, walker) < 0) { 1065 walker->stop = 1; 1066 return; 1067 } 1068 walker->count++; 1069 } 1070 } 1071 1072 static const struct Qdisc_class_ops netem_class_ops = { 1073 .graft = netem_graft, 1074 .leaf = netem_leaf, 1075 .get = netem_get, 1076 .put = netem_put, 1077 .walk = netem_walk, 1078 .dump = netem_dump_class, 1079 }; 1080 1081 static struct Qdisc_ops netem_qdisc_ops __read_mostly = { 1082 .id = "netem", 1083 .cl_ops = &netem_class_ops, 1084 .priv_size = sizeof(struct netem_sched_data), 1085 .enqueue = netem_enqueue, 1086 .dequeue = netem_dequeue, 1087 .peek = qdisc_peek_dequeued, 1088 .drop = netem_drop, 1089 .init = netem_init, 1090 .reset = netem_reset, 1091 .destroy = netem_destroy, 1092 .change = netem_change, 1093 .dump = netem_dump, 1094 .owner = THIS_MODULE, 1095 }; 1096 1097 1098 static int __init netem_module_init(void) 1099 { 1100 pr_info("netem: version " VERSION "\n"); 1101 return register_qdisc(&netem_qdisc_ops); 1102 } 1103 static void __exit netem_module_exit(void) 1104 { 1105 unregister_qdisc(&netem_qdisc_ops); 1106 } 1107 module_init(netem_module_init) 1108 module_exit(netem_module_exit) 1109 MODULE_LICENSE("GPL"); 1110