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_decrease_qlen(sch, 1); 602 } 603 } 604 goto tfifo_dequeue; 605 } 606 goto deliver; 607 } 608 609 if (q->qdisc) { 610 skb = q->qdisc->ops->dequeue(q->qdisc); 611 if (skb) 612 goto deliver; 613 } 614 qdisc_watchdog_schedule(&q->watchdog, time_to_send); 615 } 616 617 if (q->qdisc) { 618 skb = q->qdisc->ops->dequeue(q->qdisc); 619 if (skb) 620 goto deliver; 621 } 622 return NULL; 623 } 624 625 static void netem_reset(struct Qdisc *sch) 626 { 627 struct netem_sched_data *q = qdisc_priv(sch); 628 629 qdisc_reset_queue(sch); 630 tfifo_reset(sch); 631 if (q->qdisc) 632 qdisc_reset(q->qdisc); 633 qdisc_watchdog_cancel(&q->watchdog); 634 } 635 636 static void dist_free(struct disttable *d) 637 { 638 kvfree(d); 639 } 640 641 /* 642 * Distribution data is a variable size payload containing 643 * signed 16 bit values. 644 */ 645 static int get_dist_table(struct Qdisc *sch, const struct nlattr *attr) 646 { 647 struct netem_sched_data *q = qdisc_priv(sch); 648 size_t n = nla_len(attr)/sizeof(__s16); 649 const __s16 *data = nla_data(attr); 650 spinlock_t *root_lock; 651 struct disttable *d; 652 int i; 653 size_t s; 654 655 if (n > NETEM_DIST_MAX) 656 return -EINVAL; 657 658 s = sizeof(struct disttable) + n * sizeof(s16); 659 d = kmalloc(s, GFP_KERNEL | __GFP_NOWARN); 660 if (!d) 661 d = vmalloc(s); 662 if (!d) 663 return -ENOMEM; 664 665 d->size = n; 666 for (i = 0; i < n; i++) 667 d->table[i] = data[i]; 668 669 root_lock = qdisc_root_sleeping_lock(sch); 670 671 spin_lock_bh(root_lock); 672 swap(q->delay_dist, d); 673 spin_unlock_bh(root_lock); 674 675 dist_free(d); 676 return 0; 677 } 678 679 static void get_correlation(struct netem_sched_data *q, const struct nlattr *attr) 680 { 681 const struct tc_netem_corr *c = nla_data(attr); 682 683 init_crandom(&q->delay_cor, c->delay_corr); 684 init_crandom(&q->loss_cor, c->loss_corr); 685 init_crandom(&q->dup_cor, c->dup_corr); 686 } 687 688 static void get_reorder(struct netem_sched_data *q, const struct nlattr *attr) 689 { 690 const struct tc_netem_reorder *r = nla_data(attr); 691 692 q->reorder = r->probability; 693 init_crandom(&q->reorder_cor, r->correlation); 694 } 695 696 static void get_corrupt(struct netem_sched_data *q, const struct nlattr *attr) 697 { 698 const struct tc_netem_corrupt *r = nla_data(attr); 699 700 q->corrupt = r->probability; 701 init_crandom(&q->corrupt_cor, r->correlation); 702 } 703 704 static void get_rate(struct netem_sched_data *q, const struct nlattr *attr) 705 { 706 const struct tc_netem_rate *r = nla_data(attr); 707 708 q->rate = r->rate; 709 q->packet_overhead = r->packet_overhead; 710 q->cell_size = r->cell_size; 711 q->cell_overhead = r->cell_overhead; 712 if (q->cell_size) 713 q->cell_size_reciprocal = reciprocal_value(q->cell_size); 714 else 715 q->cell_size_reciprocal = (struct reciprocal_value) { 0 }; 716 } 717 718 static int get_loss_clg(struct netem_sched_data *q, const struct nlattr *attr) 719 { 720 const struct nlattr *la; 721 int rem; 722 723 nla_for_each_nested(la, attr, rem) { 724 u16 type = nla_type(la); 725 726 switch (type) { 727 case NETEM_LOSS_GI: { 728 const struct tc_netem_gimodel *gi = nla_data(la); 729 730 if (nla_len(la) < sizeof(struct tc_netem_gimodel)) { 731 pr_info("netem: incorrect gi model size\n"); 732 return -EINVAL; 733 } 734 735 q->loss_model = CLG_4_STATES; 736 737 q->clg.state = TX_IN_GAP_PERIOD; 738 q->clg.a1 = gi->p13; 739 q->clg.a2 = gi->p31; 740 q->clg.a3 = gi->p32; 741 q->clg.a4 = gi->p14; 742 q->clg.a5 = gi->p23; 743 break; 744 } 745 746 case NETEM_LOSS_GE: { 747 const struct tc_netem_gemodel *ge = nla_data(la); 748 749 if (nla_len(la) < sizeof(struct tc_netem_gemodel)) { 750 pr_info("netem: incorrect ge model size\n"); 751 return -EINVAL; 752 } 753 754 q->loss_model = CLG_GILB_ELL; 755 q->clg.state = GOOD_STATE; 756 q->clg.a1 = ge->p; 757 q->clg.a2 = ge->r; 758 q->clg.a3 = ge->h; 759 q->clg.a4 = ge->k1; 760 break; 761 } 762 763 default: 764 pr_info("netem: unknown loss type %u\n", type); 765 return -EINVAL; 766 } 767 } 768 769 return 0; 770 } 771 772 static const struct nla_policy netem_policy[TCA_NETEM_MAX + 1] = { 773 [TCA_NETEM_CORR] = { .len = sizeof(struct tc_netem_corr) }, 774 [TCA_NETEM_REORDER] = { .len = sizeof(struct tc_netem_reorder) }, 775 [TCA_NETEM_CORRUPT] = { .len = sizeof(struct tc_netem_corrupt) }, 776 [TCA_NETEM_RATE] = { .len = sizeof(struct tc_netem_rate) }, 777 [TCA_NETEM_LOSS] = { .type = NLA_NESTED }, 778 [TCA_NETEM_ECN] = { .type = NLA_U32 }, 779 [TCA_NETEM_RATE64] = { .type = NLA_U64 }, 780 }; 781 782 static int parse_attr(struct nlattr *tb[], int maxtype, struct nlattr *nla, 783 const struct nla_policy *policy, int len) 784 { 785 int nested_len = nla_len(nla) - NLA_ALIGN(len); 786 787 if (nested_len < 0) { 788 pr_info("netem: invalid attributes len %d\n", nested_len); 789 return -EINVAL; 790 } 791 792 if (nested_len >= nla_attr_size(0)) 793 return nla_parse(tb, maxtype, nla_data(nla) + NLA_ALIGN(len), 794 nested_len, policy); 795 796 memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1)); 797 return 0; 798 } 799 800 /* Parse netlink message to set options */ 801 static int netem_change(struct Qdisc *sch, struct nlattr *opt) 802 { 803 struct netem_sched_data *q = qdisc_priv(sch); 804 struct nlattr *tb[TCA_NETEM_MAX + 1]; 805 struct tc_netem_qopt *qopt; 806 struct clgstate old_clg; 807 int old_loss_model = CLG_RANDOM; 808 int ret; 809 810 if (opt == NULL) 811 return -EINVAL; 812 813 qopt = nla_data(opt); 814 ret = parse_attr(tb, TCA_NETEM_MAX, opt, netem_policy, sizeof(*qopt)); 815 if (ret < 0) 816 return ret; 817 818 /* backup q->clg and q->loss_model */ 819 old_clg = q->clg; 820 old_loss_model = q->loss_model; 821 822 if (tb[TCA_NETEM_LOSS]) { 823 ret = get_loss_clg(q, tb[TCA_NETEM_LOSS]); 824 if (ret) { 825 q->loss_model = old_loss_model; 826 return ret; 827 } 828 } else { 829 q->loss_model = CLG_RANDOM; 830 } 831 832 if (tb[TCA_NETEM_DELAY_DIST]) { 833 ret = get_dist_table(sch, tb[TCA_NETEM_DELAY_DIST]); 834 if (ret) { 835 /* recover clg and loss_model, in case of 836 * q->clg and q->loss_model were modified 837 * in get_loss_clg() 838 */ 839 q->clg = old_clg; 840 q->loss_model = old_loss_model; 841 return ret; 842 } 843 } 844 845 sch->limit = qopt->limit; 846 847 q->latency = qopt->latency; 848 q->jitter = qopt->jitter; 849 q->limit = qopt->limit; 850 q->gap = qopt->gap; 851 q->counter = 0; 852 q->loss = qopt->loss; 853 q->duplicate = qopt->duplicate; 854 855 /* for compatibility with earlier versions. 856 * if gap is set, need to assume 100% probability 857 */ 858 if (q->gap) 859 q->reorder = ~0; 860 861 if (tb[TCA_NETEM_CORR]) 862 get_correlation(q, tb[TCA_NETEM_CORR]); 863 864 if (tb[TCA_NETEM_REORDER]) 865 get_reorder(q, tb[TCA_NETEM_REORDER]); 866 867 if (tb[TCA_NETEM_CORRUPT]) 868 get_corrupt(q, tb[TCA_NETEM_CORRUPT]); 869 870 if (tb[TCA_NETEM_RATE]) 871 get_rate(q, tb[TCA_NETEM_RATE]); 872 873 if (tb[TCA_NETEM_RATE64]) 874 q->rate = max_t(u64, q->rate, 875 nla_get_u64(tb[TCA_NETEM_RATE64])); 876 877 if (tb[TCA_NETEM_ECN]) 878 q->ecn = nla_get_u32(tb[TCA_NETEM_ECN]); 879 880 return ret; 881 } 882 883 static int netem_init(struct Qdisc *sch, struct nlattr *opt) 884 { 885 struct netem_sched_data *q = qdisc_priv(sch); 886 int ret; 887 888 if (!opt) 889 return -EINVAL; 890 891 qdisc_watchdog_init(&q->watchdog, sch); 892 893 q->loss_model = CLG_RANDOM; 894 ret = netem_change(sch, opt); 895 if (ret) 896 pr_info("netem: change failed\n"); 897 return ret; 898 } 899 900 static void netem_destroy(struct Qdisc *sch) 901 { 902 struct netem_sched_data *q = qdisc_priv(sch); 903 904 qdisc_watchdog_cancel(&q->watchdog); 905 if (q->qdisc) 906 qdisc_destroy(q->qdisc); 907 dist_free(q->delay_dist); 908 } 909 910 static int dump_loss_model(const struct netem_sched_data *q, 911 struct sk_buff *skb) 912 { 913 struct nlattr *nest; 914 915 nest = nla_nest_start(skb, TCA_NETEM_LOSS); 916 if (nest == NULL) 917 goto nla_put_failure; 918 919 switch (q->loss_model) { 920 case CLG_RANDOM: 921 /* legacy loss model */ 922 nla_nest_cancel(skb, nest); 923 return 0; /* no data */ 924 925 case CLG_4_STATES: { 926 struct tc_netem_gimodel gi = { 927 .p13 = q->clg.a1, 928 .p31 = q->clg.a2, 929 .p32 = q->clg.a3, 930 .p14 = q->clg.a4, 931 .p23 = q->clg.a5, 932 }; 933 934 if (nla_put(skb, NETEM_LOSS_GI, sizeof(gi), &gi)) 935 goto nla_put_failure; 936 break; 937 } 938 case CLG_GILB_ELL: { 939 struct tc_netem_gemodel ge = { 940 .p = q->clg.a1, 941 .r = q->clg.a2, 942 .h = q->clg.a3, 943 .k1 = q->clg.a4, 944 }; 945 946 if (nla_put(skb, NETEM_LOSS_GE, sizeof(ge), &ge)) 947 goto nla_put_failure; 948 break; 949 } 950 } 951 952 nla_nest_end(skb, nest); 953 return 0; 954 955 nla_put_failure: 956 nla_nest_cancel(skb, nest); 957 return -1; 958 } 959 960 static int netem_dump(struct Qdisc *sch, struct sk_buff *skb) 961 { 962 const struct netem_sched_data *q = qdisc_priv(sch); 963 struct nlattr *nla = (struct nlattr *) skb_tail_pointer(skb); 964 struct tc_netem_qopt qopt; 965 struct tc_netem_corr cor; 966 struct tc_netem_reorder reorder; 967 struct tc_netem_corrupt corrupt; 968 struct tc_netem_rate rate; 969 970 qopt.latency = q->latency; 971 qopt.jitter = q->jitter; 972 qopt.limit = q->limit; 973 qopt.loss = q->loss; 974 qopt.gap = q->gap; 975 qopt.duplicate = q->duplicate; 976 if (nla_put(skb, TCA_OPTIONS, sizeof(qopt), &qopt)) 977 goto nla_put_failure; 978 979 cor.delay_corr = q->delay_cor.rho; 980 cor.loss_corr = q->loss_cor.rho; 981 cor.dup_corr = q->dup_cor.rho; 982 if (nla_put(skb, TCA_NETEM_CORR, sizeof(cor), &cor)) 983 goto nla_put_failure; 984 985 reorder.probability = q->reorder; 986 reorder.correlation = q->reorder_cor.rho; 987 if (nla_put(skb, TCA_NETEM_REORDER, sizeof(reorder), &reorder)) 988 goto nla_put_failure; 989 990 corrupt.probability = q->corrupt; 991 corrupt.correlation = q->corrupt_cor.rho; 992 if (nla_put(skb, TCA_NETEM_CORRUPT, sizeof(corrupt), &corrupt)) 993 goto nla_put_failure; 994 995 if (q->rate >= (1ULL << 32)) { 996 if (nla_put_u64(skb, TCA_NETEM_RATE64, q->rate)) 997 goto nla_put_failure; 998 rate.rate = ~0U; 999 } else { 1000 rate.rate = q->rate; 1001 } 1002 rate.packet_overhead = q->packet_overhead; 1003 rate.cell_size = q->cell_size; 1004 rate.cell_overhead = q->cell_overhead; 1005 if (nla_put(skb, TCA_NETEM_RATE, sizeof(rate), &rate)) 1006 goto nla_put_failure; 1007 1008 if (q->ecn && nla_put_u32(skb, TCA_NETEM_ECN, q->ecn)) 1009 goto nla_put_failure; 1010 1011 if (dump_loss_model(q, skb) != 0) 1012 goto nla_put_failure; 1013 1014 return nla_nest_end(skb, nla); 1015 1016 nla_put_failure: 1017 nlmsg_trim(skb, nla); 1018 return -1; 1019 } 1020 1021 static int netem_dump_class(struct Qdisc *sch, unsigned long cl, 1022 struct sk_buff *skb, struct tcmsg *tcm) 1023 { 1024 struct netem_sched_data *q = qdisc_priv(sch); 1025 1026 if (cl != 1 || !q->qdisc) /* only one class */ 1027 return -ENOENT; 1028 1029 tcm->tcm_handle |= TC_H_MIN(1); 1030 tcm->tcm_info = q->qdisc->handle; 1031 1032 return 0; 1033 } 1034 1035 static int netem_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, 1036 struct Qdisc **old) 1037 { 1038 struct netem_sched_data *q = qdisc_priv(sch); 1039 1040 *old = qdisc_replace(sch, new, &q->qdisc); 1041 return 0; 1042 } 1043 1044 static struct Qdisc *netem_leaf(struct Qdisc *sch, unsigned long arg) 1045 { 1046 struct netem_sched_data *q = qdisc_priv(sch); 1047 return q->qdisc; 1048 } 1049 1050 static unsigned long netem_get(struct Qdisc *sch, u32 classid) 1051 { 1052 return 1; 1053 } 1054 1055 static void netem_put(struct Qdisc *sch, unsigned long arg) 1056 { 1057 } 1058 1059 static void netem_walk(struct Qdisc *sch, struct qdisc_walker *walker) 1060 { 1061 if (!walker->stop) { 1062 if (walker->count >= walker->skip) 1063 if (walker->fn(sch, 1, walker) < 0) { 1064 walker->stop = 1; 1065 return; 1066 } 1067 walker->count++; 1068 } 1069 } 1070 1071 static const struct Qdisc_class_ops netem_class_ops = { 1072 .graft = netem_graft, 1073 .leaf = netem_leaf, 1074 .get = netem_get, 1075 .put = netem_put, 1076 .walk = netem_walk, 1077 .dump = netem_dump_class, 1078 }; 1079 1080 static struct Qdisc_ops netem_qdisc_ops __read_mostly = { 1081 .id = "netem", 1082 .cl_ops = &netem_class_ops, 1083 .priv_size = sizeof(struct netem_sched_data), 1084 .enqueue = netem_enqueue, 1085 .dequeue = netem_dequeue, 1086 .peek = qdisc_peek_dequeued, 1087 .drop = netem_drop, 1088 .init = netem_init, 1089 .reset = netem_reset, 1090 .destroy = netem_destroy, 1091 .change = netem_change, 1092 .dump = netem_dump, 1093 .owner = THIS_MODULE, 1094 }; 1095 1096 1097 static int __init netem_module_init(void) 1098 { 1099 pr_info("netem: version " VERSION "\n"); 1100 return register_qdisc(&netem_qdisc_ops); 1101 } 1102 static void __exit netem_module_exit(void) 1103 { 1104 unregister_qdisc(&netem_qdisc_ops); 1105 } 1106 module_init(netem_module_init) 1107 module_exit(netem_module_exit) 1108 MODULE_LICENSE("GPL"); 1109