| 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 | if (!skb_queue_empty(list)) { |
| 442 | /* |
| 443 | * Last packet in queue is reference point (now), |
| 444 | * calculate this time bonus and subtract |
| 445 | * from delay. |
| 446 | */ |
| 447 | delay -= netem_skb_cb(skb_peek_tail(list))->time_to_send - now; |
| 448 | delay = max_t(psched_tdiff_t, 0, delay); |
| 449 | now = netem_skb_cb(skb_peek_tail(list))->time_to_send; |
| 450 | } |
| 451 | |
| 452 | delay += packet_len_2_sched_time(skb->len, q); |
| 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"); |