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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
70struct 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 */
129struct netem_skb_cb {
130 psched_time_t time_to_send;
131};
132
133static 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 */
142static 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 */
152static 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 */
171static 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 */
235static 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
255static 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 */
287static 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
314static 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
334static 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 */
358static 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 skb_orphan(skb);
384
385 /*
386 * If we need to duplicate packet, then re-insert at top of the
387 * qdisc tree, since parent queuer expects that only one
388 * skb will be queued.
389 */
390 if (count > 1 && (skb2 = skb_clone(skb, GFP_ATOMIC)) != NULL) {
391 struct Qdisc *rootq = qdisc_root(sch);
392 u32 dupsave = q->duplicate; /* prevent duplicating a dup... */
393 q->duplicate = 0;
394
395 qdisc_enqueue_root(skb2, rootq);
396 q->duplicate = dupsave;
397 }
398
399 /*
400 * Randomized packet corruption.
401 * Make copy if needed since we are modifying
402 * If packet is going to be hardware checksummed, then
403 * do it now in software before we mangle it.
404 */
405 if (q->corrupt && q->corrupt >= get_crandom(&q->corrupt_cor)) {
406 if (!(skb = skb_unshare(skb, GFP_ATOMIC)) ||
407 (skb->ip_summed == CHECKSUM_PARTIAL &&
408 skb_checksum_help(skb)))
409 return qdisc_drop(skb, sch);
410
411 skb->data[net_random() % skb_headlen(skb)] ^= 1<<(net_random() % 8);
412 }
413
414 if (unlikely(skb_queue_len(&sch->q) >= sch->limit))
415 return qdisc_reshape_fail(skb, sch);
416
417 sch->qstats.backlog += qdisc_pkt_len(skb);
418
419 cb = netem_skb_cb(skb);
420 if (q->gap == 0 || /* not doing reordering */
421 q->counter < q->gap - 1 || /* inside last reordering gap */
422 q->reorder < get_crandom(&q->reorder_cor)) {
423 psched_time_t now;
424 psched_tdiff_t delay;
425
426 delay = tabledist(q->latency, q->jitter,
427 &q->delay_cor, q->delay_dist);
428
429 now = psched_get_time();
430
431 if (q->rate) {
432 struct sk_buff_head *list = &sch->q;
433
434 delay += packet_len_2_sched_time(skb->len, q);
435
436 if (!skb_queue_empty(list)) {
437 /*
438 * Last packet in queue is reference point (now).
439 * First packet in queue is already in flight,
440 * calculate this time bonus and substract
441 * from delay.
442 */
443 delay -= now - netem_skb_cb(skb_peek(list))->time_to_send;
444 now = netem_skb_cb(skb_peek_tail(list))->time_to_send;
445 }
446 }
447
448 cb->time_to_send = now + delay;
449 ++q->counter;
450 tfifo_enqueue(skb, sch);
451 } else {
452 /*
453 * Do re-ordering by putting one out of N packets at the front
454 * of the queue.
455 */
456 cb->time_to_send = psched_get_time();
457 q->counter = 0;
458
459 __skb_queue_head(&sch->q, skb);
460 sch->qstats.requeues++;
461 }
462
463 return NET_XMIT_SUCCESS;
464}
465
466static unsigned int netem_drop(struct Qdisc *sch)
467{
468 struct netem_sched_data *q = qdisc_priv(sch);
469 unsigned int len;
470
471 len = qdisc_queue_drop(sch);
472 if (!len && q->qdisc && q->qdisc->ops->drop)
473 len = q->qdisc->ops->drop(q->qdisc);
474 if (len)
475 sch->qstats.drops++;
476
477 return len;
478}
479
480static struct sk_buff *netem_dequeue(struct Qdisc *sch)
481{
482 struct netem_sched_data *q = qdisc_priv(sch);
483 struct sk_buff *skb;
484
485 if (qdisc_is_throttled(sch))
486 return NULL;
487
488tfifo_dequeue:
489 skb = qdisc_peek_head(sch);
490 if (skb) {
491 const struct netem_skb_cb *cb = netem_skb_cb(skb);
492
493 /* if more time remaining? */
494 if (cb->time_to_send <= psched_get_time()) {
495 __skb_unlink(skb, &sch->q);
496 sch->qstats.backlog -= qdisc_pkt_len(skb);
497
498#ifdef CONFIG_NET_CLS_ACT
499 /*
500 * If it's at ingress let's pretend the delay is
501 * from the network (tstamp will be updated).
502 */
503 if (G_TC_FROM(skb->tc_verd) & AT_INGRESS)
504 skb->tstamp.tv64 = 0;
505#endif
506
507 if (q->qdisc) {
508 int err = qdisc_enqueue(skb, q->qdisc);
509
510 if (unlikely(err != NET_XMIT_SUCCESS)) {
511 if (net_xmit_drop_count(err)) {
512 sch->qstats.drops++;
513 qdisc_tree_decrease_qlen(sch, 1);
514 }
515 }
516 goto tfifo_dequeue;
517 }
518deliver:
519 qdisc_unthrottled(sch);
520 qdisc_bstats_update(sch, skb);
521 return skb;
522 }
523
524 if (q->qdisc) {
525 skb = q->qdisc->ops->dequeue(q->qdisc);
526 if (skb)
527 goto deliver;
528 }
529 qdisc_watchdog_schedule(&q->watchdog, cb->time_to_send);
530 }
531
532 if (q->qdisc) {
533 skb = q->qdisc->ops->dequeue(q->qdisc);
534 if (skb)
535 goto deliver;
536 }
537 return NULL;
538}
539
540static void netem_reset(struct Qdisc *sch)
541{
542 struct netem_sched_data *q = qdisc_priv(sch);
543
544 qdisc_reset_queue(sch);
545 if (q->qdisc)
546 qdisc_reset(q->qdisc);
547 qdisc_watchdog_cancel(&q->watchdog);
548}
549
550static void dist_free(struct disttable *d)
551{
552 if (d) {
553 if (is_vmalloc_addr(d))
554 vfree(d);
555 else
556 kfree(d);
557 }
558}
559
560/*
561 * Distribution data is a variable size payload containing
562 * signed 16 bit values.
563 */
564static int get_dist_table(struct Qdisc *sch, const struct nlattr *attr)
565{
566 struct netem_sched_data *q = qdisc_priv(sch);
567 size_t n = nla_len(attr)/sizeof(__s16);
568 const __s16 *data = nla_data(attr);
569 spinlock_t *root_lock;
570 struct disttable *d;
571 int i;
572 size_t s;
573
574 if (n > NETEM_DIST_MAX)
575 return -EINVAL;
576
577 s = sizeof(struct disttable) + n * sizeof(s16);
578 d = kmalloc(s, GFP_KERNEL | __GFP_NOWARN);
579 if (!d)
580 d = vmalloc(s);
581 if (!d)
582 return -ENOMEM;
583
584 d->size = n;
585 for (i = 0; i < n; i++)
586 d->table[i] = data[i];
587
588 root_lock = qdisc_root_sleeping_lock(sch);
589
590 spin_lock_bh(root_lock);
591 swap(q->delay_dist, d);
592 spin_unlock_bh(root_lock);
593
594 dist_free(d);
595 return 0;
596}
597
598static void get_correlation(struct Qdisc *sch, const struct nlattr *attr)
599{
600 struct netem_sched_data *q = qdisc_priv(sch);
601 const struct tc_netem_corr *c = nla_data(attr);
602
603 init_crandom(&q->delay_cor, c->delay_corr);
604 init_crandom(&q->loss_cor, c->loss_corr);
605 init_crandom(&q->dup_cor, c->dup_corr);
606}
607
608static void get_reorder(struct Qdisc *sch, const struct nlattr *attr)
609{
610 struct netem_sched_data *q = qdisc_priv(sch);
611 const struct tc_netem_reorder *r = nla_data(attr);
612
613 q->reorder = r->probability;
614 init_crandom(&q->reorder_cor, r->correlation);
615}
616
617static void get_corrupt(struct Qdisc *sch, const struct nlattr *attr)
618{
619 struct netem_sched_data *q = qdisc_priv(sch);
620 const struct tc_netem_corrupt *r = nla_data(attr);
621
622 q->corrupt = r->probability;
623 init_crandom(&q->corrupt_cor, r->correlation);
624}
625
626static void get_rate(struct Qdisc *sch, const struct nlattr *attr)
627{
628 struct netem_sched_data *q = qdisc_priv(sch);
629 const struct tc_netem_rate *r = nla_data(attr);
630
631 q->rate = r->rate;
632 q->packet_overhead = r->packet_overhead;
633 q->cell_size = r->cell_size;
634 if (q->cell_size)
635 q->cell_size_reciprocal = reciprocal_value(q->cell_size);
636 q->cell_overhead = r->cell_overhead;
637}
638
639static int get_loss_clg(struct Qdisc *sch, const struct nlattr *attr)
640{
641 struct netem_sched_data *q = qdisc_priv(sch);
642 const struct nlattr *la;
643 int rem;
644
645 nla_for_each_nested(la, attr, rem) {
646 u16 type = nla_type(la);
647
648 switch(type) {
649 case NETEM_LOSS_GI: {
650 const struct tc_netem_gimodel *gi = nla_data(la);
651
652 if (nla_len(la) < sizeof(struct tc_netem_gimodel)) {
653 pr_info("netem: incorrect gi model size\n");
654 return -EINVAL;
655 }
656
657 q->loss_model = CLG_4_STATES;
658
659 q->clg.state = 1;
660 q->clg.a1 = gi->p13;
661 q->clg.a2 = gi->p31;
662 q->clg.a3 = gi->p32;
663 q->clg.a4 = gi->p14;
664 q->clg.a5 = gi->p23;
665 break;
666 }
667
668 case NETEM_LOSS_GE: {
669 const struct tc_netem_gemodel *ge = nla_data(la);
670
671 if (nla_len(la) < sizeof(struct tc_netem_gemodel)) {
672 pr_info("netem: incorrect ge model size\n");
673 return -EINVAL;
674 }
675
676 q->loss_model = CLG_GILB_ELL;
677 q->clg.state = 1;
678 q->clg.a1 = ge->p;
679 q->clg.a2 = ge->r;
680 q->clg.a3 = ge->h;
681 q->clg.a4 = ge->k1;
682 break;
683 }
684
685 default:
686 pr_info("netem: unknown loss type %u\n", type);
687 return -EINVAL;
688 }
689 }
690
691 return 0;
692}
693
694static const struct nla_policy netem_policy[TCA_NETEM_MAX + 1] = {
695 [TCA_NETEM_CORR] = { .len = sizeof(struct tc_netem_corr) },
696 [TCA_NETEM_REORDER] = { .len = sizeof(struct tc_netem_reorder) },
697 [TCA_NETEM_CORRUPT] = { .len = sizeof(struct tc_netem_corrupt) },
698 [TCA_NETEM_RATE] = { .len = sizeof(struct tc_netem_rate) },
699 [TCA_NETEM_LOSS] = { .type = NLA_NESTED },
700 [TCA_NETEM_ECN] = { .type = NLA_U32 },
701};
702
703static int parse_attr(struct nlattr *tb[], int maxtype, struct nlattr *nla,
704 const struct nla_policy *policy, int len)
705{
706 int nested_len = nla_len(nla) - NLA_ALIGN(len);
707
708 if (nested_len < 0) {
709 pr_info("netem: invalid attributes len %d\n", nested_len);
710 return -EINVAL;
711 }
712
713 if (nested_len >= nla_attr_size(0))
714 return nla_parse(tb, maxtype, nla_data(nla) + NLA_ALIGN(len),
715 nested_len, policy);
716
717 memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
718 return 0;
719}
720
721/* Parse netlink message to set options */
722static int netem_change(struct Qdisc *sch, struct nlattr *opt)
723{
724 struct netem_sched_data *q = qdisc_priv(sch);
725 struct nlattr *tb[TCA_NETEM_MAX + 1];
726 struct tc_netem_qopt *qopt;
727 int ret;
728
729 if (opt == NULL)
730 return -EINVAL;
731
732 qopt = nla_data(opt);
733 ret = parse_attr(tb, TCA_NETEM_MAX, opt, netem_policy, sizeof(*qopt));
734 if (ret < 0)
735 return ret;
736
737 sch->limit = qopt->limit;
738
739 q->latency = qopt->latency;
740 q->jitter = qopt->jitter;
741 q->limit = qopt->limit;
742 q->gap = qopt->gap;
743 q->counter = 0;
744 q->loss = qopt->loss;
745 q->duplicate = qopt->duplicate;
746
747 /* for compatibility with earlier versions.
748 * if gap is set, need to assume 100% probability
749 */
750 if (q->gap)
751 q->reorder = ~0;
752
753 if (tb[TCA_NETEM_CORR])
754 get_correlation(sch, tb[TCA_NETEM_CORR]);
755
756 if (tb[TCA_NETEM_DELAY_DIST]) {
757 ret = get_dist_table(sch, tb[TCA_NETEM_DELAY_DIST]);
758 if (ret)
759 return ret;
760 }
761
762 if (tb[TCA_NETEM_REORDER])
763 get_reorder(sch, tb[TCA_NETEM_REORDER]);
764
765 if (tb[TCA_NETEM_CORRUPT])
766 get_corrupt(sch, tb[TCA_NETEM_CORRUPT]);
767
768 if (tb[TCA_NETEM_RATE])
769 get_rate(sch, tb[TCA_NETEM_RATE]);
770
771 if (tb[TCA_NETEM_ECN])
772 q->ecn = nla_get_u32(tb[TCA_NETEM_ECN]);
773
774 q->loss_model = CLG_RANDOM;
775 if (tb[TCA_NETEM_LOSS])
776 ret = get_loss_clg(sch, tb[TCA_NETEM_LOSS]);
777
778 return ret;
779}
780
781static int netem_init(struct Qdisc *sch, struct nlattr *opt)
782{
783 struct netem_sched_data *q = qdisc_priv(sch);
784 int ret;
785
786 if (!opt)
787 return -EINVAL;
788
789 qdisc_watchdog_init(&q->watchdog, sch);
790
791 q->loss_model = CLG_RANDOM;
792 ret = netem_change(sch, opt);
793 if (ret)
794 pr_info("netem: change failed\n");
795 return ret;
796}
797
798static void netem_destroy(struct Qdisc *sch)
799{
800 struct netem_sched_data *q = qdisc_priv(sch);
801
802 qdisc_watchdog_cancel(&q->watchdog);
803 if (q->qdisc)
804 qdisc_destroy(q->qdisc);
805 dist_free(q->delay_dist);
806}
807
808static int dump_loss_model(const struct netem_sched_data *q,
809 struct sk_buff *skb)
810{
811 struct nlattr *nest;
812
813 nest = nla_nest_start(skb, TCA_NETEM_LOSS);
814 if (nest == NULL)
815 goto nla_put_failure;
816
817 switch (q->loss_model) {
818 case CLG_RANDOM:
819 /* legacy loss model */
820 nla_nest_cancel(skb, nest);
821 return 0; /* no data */
822
823 case CLG_4_STATES: {
824 struct tc_netem_gimodel gi = {
825 .p13 = q->clg.a1,
826 .p31 = q->clg.a2,
827 .p32 = q->clg.a3,
828 .p14 = q->clg.a4,
829 .p23 = q->clg.a5,
830 };
831
832 if (nla_put(skb, NETEM_LOSS_GI, sizeof(gi), &gi))
833 goto nla_put_failure;
834 break;
835 }
836 case CLG_GILB_ELL: {
837 struct tc_netem_gemodel ge = {
838 .p = q->clg.a1,
839 .r = q->clg.a2,
840 .h = q->clg.a3,
841 .k1 = q->clg.a4,
842 };
843
844 if (nla_put(skb, NETEM_LOSS_GE, sizeof(ge), &ge))
845 goto nla_put_failure;
846 break;
847 }
848 }
849
850 nla_nest_end(skb, nest);
851 return 0;
852
853nla_put_failure:
854 nla_nest_cancel(skb, nest);
855 return -1;
856}
857
858static int netem_dump(struct Qdisc *sch, struct sk_buff *skb)
859{
860 const struct netem_sched_data *q = qdisc_priv(sch);
861 struct nlattr *nla = (struct nlattr *) skb_tail_pointer(skb);
862 struct tc_netem_qopt qopt;
863 struct tc_netem_corr cor;
864 struct tc_netem_reorder reorder;
865 struct tc_netem_corrupt corrupt;
866 struct tc_netem_rate rate;
867
868 qopt.latency = q->latency;
869 qopt.jitter = q->jitter;
870 qopt.limit = q->limit;
871 qopt.loss = q->loss;
872 qopt.gap = q->gap;
873 qopt.duplicate = q->duplicate;
874 if (nla_put(skb, TCA_OPTIONS, sizeof(qopt), &qopt))
875 goto nla_put_failure;
876
877 cor.delay_corr = q->delay_cor.rho;
878 cor.loss_corr = q->loss_cor.rho;
879 cor.dup_corr = q->dup_cor.rho;
880 if (nla_put(skb, TCA_NETEM_CORR, sizeof(cor), &cor))
881 goto nla_put_failure;
882
883 reorder.probability = q->reorder;
884 reorder.correlation = q->reorder_cor.rho;
885 if (nla_put(skb, TCA_NETEM_REORDER, sizeof(reorder), &reorder))
886 goto nla_put_failure;
887
888 corrupt.probability = q->corrupt;
889 corrupt.correlation = q->corrupt_cor.rho;
890 if (nla_put(skb, TCA_NETEM_CORRUPT, sizeof(corrupt), &corrupt))
891 goto nla_put_failure;
892
893 rate.rate = q->rate;
894 rate.packet_overhead = q->packet_overhead;
895 rate.cell_size = q->cell_size;
896 rate.cell_overhead = q->cell_overhead;
897 if (nla_put(skb, TCA_NETEM_RATE, sizeof(rate), &rate))
898 goto nla_put_failure;
899
900 if (q->ecn && nla_put_u32(skb, TCA_NETEM_ECN, q->ecn))
901 goto nla_put_failure;
902
903 if (dump_loss_model(q, skb) != 0)
904 goto nla_put_failure;
905
906 return nla_nest_end(skb, nla);
907
908nla_put_failure:
909 nlmsg_trim(skb, nla);
910 return -1;
911}
912
913static int netem_dump_class(struct Qdisc *sch, unsigned long cl,
914 struct sk_buff *skb, struct tcmsg *tcm)
915{
916 struct netem_sched_data *q = qdisc_priv(sch);
917
918 if (cl != 1 || !q->qdisc) /* only one class */
919 return -ENOENT;
920
921 tcm->tcm_handle |= TC_H_MIN(1);
922 tcm->tcm_info = q->qdisc->handle;
923
924 return 0;
925}
926
927static int netem_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
928 struct Qdisc **old)
929{
930 struct netem_sched_data *q = qdisc_priv(sch);
931
932 sch_tree_lock(sch);
933 *old = q->qdisc;
934 q->qdisc = new;
935 if (*old) {
936 qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
937 qdisc_reset(*old);
938 }
939 sch_tree_unlock(sch);
940
941 return 0;
942}
943
944static struct Qdisc *netem_leaf(struct Qdisc *sch, unsigned long arg)
945{
946 struct netem_sched_data *q = qdisc_priv(sch);
947 return q->qdisc;
948}
949
950static unsigned long netem_get(struct Qdisc *sch, u32 classid)
951{
952 return 1;
953}
954
955static void netem_put(struct Qdisc *sch, unsigned long arg)
956{
957}
958
959static void netem_walk(struct Qdisc *sch, struct qdisc_walker *walker)
960{
961 if (!walker->stop) {
962 if (walker->count >= walker->skip)
963 if (walker->fn(sch, 1, walker) < 0) {
964 walker->stop = 1;
965 return;
966 }
967 walker->count++;
968 }
969}
970
971static const struct Qdisc_class_ops netem_class_ops = {
972 .graft = netem_graft,
973 .leaf = netem_leaf,
974 .get = netem_get,
975 .put = netem_put,
976 .walk = netem_walk,
977 .dump = netem_dump_class,
978};
979
980static struct Qdisc_ops netem_qdisc_ops __read_mostly = {
981 .id = "netem",
982 .cl_ops = &netem_class_ops,
983 .priv_size = sizeof(struct netem_sched_data),
984 .enqueue = netem_enqueue,
985 .dequeue = netem_dequeue,
986 .peek = qdisc_peek_dequeued,
987 .drop = netem_drop,
988 .init = netem_init,
989 .reset = netem_reset,
990 .destroy = netem_destroy,
991 .change = netem_change,
992 .dump = netem_dump,
993 .owner = THIS_MODULE,
994};
995
996
997static int __init netem_module_init(void)
998{
999 pr_info("netem: version " VERSION "\n");
1000 return register_qdisc(&netem_qdisc_ops);
1001}
1002static void __exit netem_module_exit(void)
1003{
1004 unregister_qdisc(&netem_qdisc_ops);
1005}
1006module_init(netem_module_init)
1007module_exit(netem_module_exit)
1008MODULE_LICENSE("GPL");
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * net/sched/sch_netem.c Network emulator
4 *
5 * Many of the algorithms and ideas for this came from
6 * NIST Net which is not copyrighted.
7 *
8 * Authors: Stephen Hemminger <shemminger@osdl.org>
9 * Catalin(ux aka Dino) BOIE <catab at umbrella dot ro>
10 */
11
12#include <linux/mm.h>
13#include <linux/module.h>
14#include <linux/slab.h>
15#include <linux/types.h>
16#include <linux/kernel.h>
17#include <linux/errno.h>
18#include <linux/skbuff.h>
19#include <linux/vmalloc.h>
20#include <linux/prandom.h>
21#include <linux/rtnetlink.h>
22#include <linux/reciprocal_div.h>
23#include <linux/rbtree.h>
24
25#include <net/gso.h>
26#include <net/netlink.h>
27#include <net/pkt_sched.h>
28#include <net/inet_ecn.h>
29
30#define VERSION "1.3"
31
32/* Network Emulation Queuing algorithm.
33 ====================================
34
35 Sources: [1] Mark Carson, Darrin Santay, "NIST Net - A Linux-based
36 Network Emulation Tool
37 [2] Luigi Rizzo, DummyNet for FreeBSD
38
39 ----------------------------------------------------------------
40
41 This started out as a simple way to delay outgoing packets to
42 test TCP but has grown to include most of the functionality
43 of a full blown network emulator like NISTnet. It can delay
44 packets and add random jitter (and correlation). The random
45 distribution can be loaded from a table as well to provide
46 normal, Pareto, or experimental curves. Packet loss,
47 duplication, and reordering can also be emulated.
48
49 This qdisc does not do classification that can be handled in
50 layering other disciplines. It does not need to do bandwidth
51 control either since that can be handled by using token
52 bucket or other rate control.
53
54 Correlated Loss Generator models
55
56 Added generation of correlated loss according to the
57 "Gilbert-Elliot" model, a 4-state markov model.
58
59 References:
60 [1] NetemCLG Home http://netgroup.uniroma2.it/NetemCLG
61 [2] S. Salsano, F. Ludovici, A. Ordine, "Definition of a general
62 and intuitive loss model for packet networks and its implementation
63 in the Netem module in the Linux kernel", available in [1]
64
65 Authors: Stefano Salsano <stefano.salsano at uniroma2.it
66 Fabio Ludovici <fabio.ludovici at yahoo.it>
67*/
68
69struct disttable {
70 u32 size;
71 s16 table[] __counted_by(size);
72};
73
74struct netem_sched_data {
75 /* internal t(ime)fifo qdisc uses t_root and sch->limit */
76 struct rb_root t_root;
77
78 /* a linear queue; reduces rbtree rebalancing when jitter is low */
79 struct sk_buff *t_head;
80 struct sk_buff *t_tail;
81
82 u32 t_len;
83
84 /* optional qdisc for classful handling (NULL at netem init) */
85 struct Qdisc *qdisc;
86
87 struct qdisc_watchdog watchdog;
88
89 s64 latency;
90 s64 jitter;
91
92 u32 loss;
93 u32 ecn;
94 u32 limit;
95 u32 counter;
96 u32 gap;
97 u32 duplicate;
98 u32 reorder;
99 u32 corrupt;
100 u64 rate;
101 s32 packet_overhead;
102 u32 cell_size;
103 struct reciprocal_value cell_size_reciprocal;
104 s32 cell_overhead;
105
106 struct crndstate {
107 u32 last;
108 u32 rho;
109 } delay_cor, loss_cor, dup_cor, reorder_cor, corrupt_cor;
110
111 struct prng {
112 u64 seed;
113 struct rnd_state prng_state;
114 } prng;
115
116 struct disttable *delay_dist;
117
118 enum {
119 CLG_RANDOM,
120 CLG_4_STATES,
121 CLG_GILB_ELL,
122 } loss_model;
123
124 enum {
125 TX_IN_GAP_PERIOD = 1,
126 TX_IN_BURST_PERIOD,
127 LOST_IN_GAP_PERIOD,
128 LOST_IN_BURST_PERIOD,
129 } _4_state_model;
130
131 enum {
132 GOOD_STATE = 1,
133 BAD_STATE,
134 } GE_state_model;
135
136 /* Correlated Loss Generation models */
137 struct clgstate {
138 /* state of the Markov chain */
139 u8 state;
140
141 /* 4-states and Gilbert-Elliot models */
142 u32 a1; /* p13 for 4-states or p for GE */
143 u32 a2; /* p31 for 4-states or r for GE */
144 u32 a3; /* p32 for 4-states or h for GE */
145 u32 a4; /* p14 for 4-states or 1-k for GE */
146 u32 a5; /* p23 used only in 4-states */
147 } clg;
148
149 struct tc_netem_slot slot_config;
150 struct slotstate {
151 u64 slot_next;
152 s32 packets_left;
153 s32 bytes_left;
154 } slot;
155
156 struct disttable *slot_dist;
157};
158
159/* Time stamp put into socket buffer control block
160 * Only valid when skbs are in our internal t(ime)fifo queue.
161 *
162 * As skb->rbnode uses same storage than skb->next, skb->prev and skb->tstamp,
163 * and skb->next & skb->prev are scratch space for a qdisc,
164 * we save skb->tstamp value in skb->cb[] before destroying it.
165 */
166struct netem_skb_cb {
167 u64 time_to_send;
168};
169
170static inline struct netem_skb_cb *netem_skb_cb(struct sk_buff *skb)
171{
172 /* we assume we can use skb next/prev/tstamp as storage for rb_node */
173 qdisc_cb_private_validate(skb, sizeof(struct netem_skb_cb));
174 return (struct netem_skb_cb *)qdisc_skb_cb(skb)->data;
175}
176
177/* init_crandom - initialize correlated random number generator
178 * Use entropy source for initial seed.
179 */
180static void init_crandom(struct crndstate *state, unsigned long rho)
181{
182 state->rho = rho;
183 state->last = get_random_u32();
184}
185
186/* get_crandom - correlated random number generator
187 * Next number depends on last value.
188 * rho is scaled to avoid floating point.
189 */
190static u32 get_crandom(struct crndstate *state, struct prng *p)
191{
192 u64 value, rho;
193 unsigned long answer;
194 struct rnd_state *s = &p->prng_state;
195
196 if (!state || state->rho == 0) /* no correlation */
197 return prandom_u32_state(s);
198
199 value = prandom_u32_state(s);
200 rho = (u64)state->rho + 1;
201 answer = (value * ((1ull<<32) - rho) + state->last * rho) >> 32;
202 state->last = answer;
203 return answer;
204}
205
206/* loss_4state - 4-state model loss generator
207 * Generates losses according to the 4-state Markov chain adopted in
208 * the GI (General and Intuitive) loss model.
209 */
210static bool loss_4state(struct netem_sched_data *q)
211{
212 struct clgstate *clg = &q->clg;
213 u32 rnd = prandom_u32_state(&q->prng.prng_state);
214
215 /*
216 * Makes a comparison between rnd and the transition
217 * probabilities outgoing from the current state, then decides the
218 * next state and if the next packet has to be transmitted or lost.
219 * The four states correspond to:
220 * TX_IN_GAP_PERIOD => successfully transmitted packets within a gap period
221 * LOST_IN_GAP_PERIOD => isolated losses within a gap period
222 * LOST_IN_BURST_PERIOD => lost packets within a burst period
223 * TX_IN_BURST_PERIOD => successfully transmitted packets within a burst period
224 */
225 switch (clg->state) {
226 case TX_IN_GAP_PERIOD:
227 if (rnd < clg->a4) {
228 clg->state = LOST_IN_GAP_PERIOD;
229 return true;
230 } else if (clg->a4 < rnd && rnd < clg->a1 + clg->a4) {
231 clg->state = LOST_IN_BURST_PERIOD;
232 return true;
233 } else if (clg->a1 + clg->a4 < rnd) {
234 clg->state = TX_IN_GAP_PERIOD;
235 }
236
237 break;
238 case TX_IN_BURST_PERIOD:
239 if (rnd < clg->a5) {
240 clg->state = LOST_IN_BURST_PERIOD;
241 return true;
242 } else {
243 clg->state = TX_IN_BURST_PERIOD;
244 }
245
246 break;
247 case LOST_IN_BURST_PERIOD:
248 if (rnd < clg->a3)
249 clg->state = TX_IN_BURST_PERIOD;
250 else if (clg->a3 < rnd && rnd < clg->a2 + clg->a3) {
251 clg->state = TX_IN_GAP_PERIOD;
252 } else if (clg->a2 + clg->a3 < rnd) {
253 clg->state = LOST_IN_BURST_PERIOD;
254 return true;
255 }
256 break;
257 case LOST_IN_GAP_PERIOD:
258 clg->state = TX_IN_GAP_PERIOD;
259 break;
260 }
261
262 return false;
263}
264
265/* loss_gilb_ell - Gilbert-Elliot model loss generator
266 * Generates losses according to the Gilbert-Elliot loss model or
267 * its special cases (Gilbert or Simple Gilbert)
268 *
269 * Makes a comparison between random number and the transition
270 * probabilities outgoing from the current state, then decides the
271 * next state. A second random number is extracted and the comparison
272 * with the loss probability of the current state decides if the next
273 * packet will be transmitted or lost.
274 */
275static bool loss_gilb_ell(struct netem_sched_data *q)
276{
277 struct clgstate *clg = &q->clg;
278 struct rnd_state *s = &q->prng.prng_state;
279
280 switch (clg->state) {
281 case GOOD_STATE:
282 if (prandom_u32_state(s) < clg->a1)
283 clg->state = BAD_STATE;
284 if (prandom_u32_state(s) < clg->a4)
285 return true;
286 break;
287 case BAD_STATE:
288 if (prandom_u32_state(s) < clg->a2)
289 clg->state = GOOD_STATE;
290 if (prandom_u32_state(s) > clg->a3)
291 return true;
292 }
293
294 return false;
295}
296
297static bool loss_event(struct netem_sched_data *q)
298{
299 switch (q->loss_model) {
300 case CLG_RANDOM:
301 /* Random packet drop 0 => none, ~0 => all */
302 return q->loss && q->loss >= get_crandom(&q->loss_cor, &q->prng);
303
304 case CLG_4_STATES:
305 /* 4state loss model algorithm (used also for GI model)
306 * Extracts a value from the markov 4 state loss generator,
307 * if it is 1 drops a packet and if needed writes the event in
308 * the kernel logs
309 */
310 return loss_4state(q);
311
312 case CLG_GILB_ELL:
313 /* Gilbert-Elliot loss model algorithm
314 * Extracts a value from the Gilbert-Elliot loss generator,
315 * if it is 1 drops a packet and if needed writes the event in
316 * the kernel logs
317 */
318 return loss_gilb_ell(q);
319 }
320
321 return false; /* not reached */
322}
323
324
325/* tabledist - return a pseudo-randomly distributed value with mean mu and
326 * std deviation sigma. Uses table lookup to approximate the desired
327 * distribution, and a uniformly-distributed pseudo-random source.
328 */
329static s64 tabledist(s64 mu, s32 sigma,
330 struct crndstate *state,
331 struct prng *prng,
332 const struct disttable *dist)
333{
334 s64 x;
335 long t;
336 u32 rnd;
337
338 if (sigma == 0)
339 return mu;
340
341 rnd = get_crandom(state, prng);
342
343 /* default uniform distribution */
344 if (dist == NULL)
345 return ((rnd % (2 * (u32)sigma)) + mu) - sigma;
346
347 t = dist->table[rnd % dist->size];
348 x = (sigma % NETEM_DIST_SCALE) * t;
349 if (x >= 0)
350 x += NETEM_DIST_SCALE/2;
351 else
352 x -= NETEM_DIST_SCALE/2;
353
354 return x / NETEM_DIST_SCALE + (sigma / NETEM_DIST_SCALE) * t + mu;
355}
356
357static u64 packet_time_ns(u64 len, const struct netem_sched_data *q)
358{
359 len += q->packet_overhead;
360
361 if (q->cell_size) {
362 u32 cells = reciprocal_divide(len, q->cell_size_reciprocal);
363
364 if (len > cells * q->cell_size) /* extra cell needed for remainder */
365 cells++;
366 len = cells * (q->cell_size + q->cell_overhead);
367 }
368
369 return div64_u64(len * NSEC_PER_SEC, q->rate);
370}
371
372static void tfifo_reset(struct Qdisc *sch)
373{
374 struct netem_sched_data *q = qdisc_priv(sch);
375 struct rb_node *p = rb_first(&q->t_root);
376
377 while (p) {
378 struct sk_buff *skb = rb_to_skb(p);
379
380 p = rb_next(p);
381 rb_erase(&skb->rbnode, &q->t_root);
382 rtnl_kfree_skbs(skb, skb);
383 }
384
385 rtnl_kfree_skbs(q->t_head, q->t_tail);
386 q->t_head = NULL;
387 q->t_tail = NULL;
388 q->t_len = 0;
389}
390
391static void tfifo_enqueue(struct sk_buff *nskb, struct Qdisc *sch)
392{
393 struct netem_sched_data *q = qdisc_priv(sch);
394 u64 tnext = netem_skb_cb(nskb)->time_to_send;
395
396 if (!q->t_tail || tnext >= netem_skb_cb(q->t_tail)->time_to_send) {
397 if (q->t_tail)
398 q->t_tail->next = nskb;
399 else
400 q->t_head = nskb;
401 q->t_tail = nskb;
402 } else {
403 struct rb_node **p = &q->t_root.rb_node, *parent = NULL;
404
405 while (*p) {
406 struct sk_buff *skb;
407
408 parent = *p;
409 skb = rb_to_skb(parent);
410 if (tnext >= netem_skb_cb(skb)->time_to_send)
411 p = &parent->rb_right;
412 else
413 p = &parent->rb_left;
414 }
415 rb_link_node(&nskb->rbnode, parent, p);
416 rb_insert_color(&nskb->rbnode, &q->t_root);
417 }
418 q->t_len++;
419 sch->q.qlen++;
420}
421
422/* netem can't properly corrupt a megapacket (like we get from GSO), so instead
423 * when we statistically choose to corrupt one, we instead segment it, returning
424 * the first packet to be corrupted, and re-enqueue the remaining frames
425 */
426static struct sk_buff *netem_segment(struct sk_buff *skb, struct Qdisc *sch,
427 struct sk_buff **to_free)
428{
429 struct sk_buff *segs;
430 netdev_features_t features = netif_skb_features(skb);
431
432 segs = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK);
433
434 if (IS_ERR_OR_NULL(segs)) {
435 qdisc_drop(skb, sch, to_free);
436 return NULL;
437 }
438 consume_skb(skb);
439 return segs;
440}
441
442/*
443 * Insert one skb into qdisc.
444 * Note: parent depends on return value to account for queue length.
445 * NET_XMIT_DROP: queue length didn't change.
446 * NET_XMIT_SUCCESS: one skb was queued.
447 */
448static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
449 struct sk_buff **to_free)
450{
451 struct netem_sched_data *q = qdisc_priv(sch);
452 /* We don't fill cb now as skb_unshare() may invalidate it */
453 struct netem_skb_cb *cb;
454 struct sk_buff *skb2 = NULL;
455 struct sk_buff *segs = NULL;
456 unsigned int prev_len = qdisc_pkt_len(skb);
457 int count = 1;
458
459 /* Do not fool qdisc_drop_all() */
460 skb->prev = NULL;
461
462 /* Random duplication */
463 if (q->duplicate && q->duplicate >= get_crandom(&q->dup_cor, &q->prng))
464 ++count;
465
466 /* Drop packet? */
467 if (loss_event(q)) {
468 if (q->ecn && INET_ECN_set_ce(skb))
469 qdisc_qstats_drop(sch); /* mark packet */
470 else
471 --count;
472 }
473 if (count == 0) {
474 qdisc_qstats_drop(sch);
475 __qdisc_drop(skb, to_free);
476 return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
477 }
478
479 /* If a delay is expected, orphan the skb. (orphaning usually takes
480 * place at TX completion time, so _before_ the link transit delay)
481 */
482 if (q->latency || q->jitter || q->rate)
483 skb_orphan_partial(skb);
484
485 /*
486 * If we need to duplicate packet, then clone it before
487 * original is modified.
488 */
489 if (count > 1)
490 skb2 = skb_clone(skb, GFP_ATOMIC);
491
492 /*
493 * Randomized packet corruption.
494 * Make copy if needed since we are modifying
495 * If packet is going to be hardware checksummed, then
496 * do it now in software before we mangle it.
497 */
498 if (q->corrupt && q->corrupt >= get_crandom(&q->corrupt_cor, &q->prng)) {
499 if (skb_is_gso(skb)) {
500 skb = netem_segment(skb, sch, to_free);
501 if (!skb)
502 goto finish_segs;
503
504 segs = skb->next;
505 skb_mark_not_on_list(skb);
506 qdisc_skb_cb(skb)->pkt_len = skb->len;
507 }
508
509 skb = skb_unshare(skb, GFP_ATOMIC);
510 if (unlikely(!skb)) {
511 qdisc_qstats_drop(sch);
512 goto finish_segs;
513 }
514 if (skb->ip_summed == CHECKSUM_PARTIAL &&
515 skb_checksum_help(skb)) {
516 qdisc_drop(skb, sch, to_free);
517 skb = NULL;
518 goto finish_segs;
519 }
520
521 skb->data[get_random_u32_below(skb_headlen(skb))] ^=
522 1<<get_random_u32_below(8);
523 }
524
525 if (unlikely(q->t_len >= sch->limit)) {
526 /* re-link segs, so that qdisc_drop_all() frees them all */
527 skb->next = segs;
528 qdisc_drop_all(skb, sch, to_free);
529 if (skb2)
530 __qdisc_drop(skb2, to_free);
531 return NET_XMIT_DROP;
532 }
533
534 /*
535 * If doing duplication then re-insert at top of the
536 * qdisc tree, since parent queuer expects that only one
537 * skb will be queued.
538 */
539 if (skb2) {
540 struct Qdisc *rootq = qdisc_root_bh(sch);
541 u32 dupsave = q->duplicate; /* prevent duplicating a dup... */
542
543 q->duplicate = 0;
544 rootq->enqueue(skb2, rootq, to_free);
545 q->duplicate = dupsave;
546 skb2 = NULL;
547 }
548
549 qdisc_qstats_backlog_inc(sch, skb);
550
551 cb = netem_skb_cb(skb);
552 if (q->gap == 0 || /* not doing reordering */
553 q->counter < q->gap - 1 || /* inside last reordering gap */
554 q->reorder < get_crandom(&q->reorder_cor, &q->prng)) {
555 u64 now;
556 s64 delay;
557
558 delay = tabledist(q->latency, q->jitter,
559 &q->delay_cor, &q->prng, q->delay_dist);
560
561 now = ktime_get_ns();
562
563 if (q->rate) {
564 struct netem_skb_cb *last = NULL;
565
566 if (sch->q.tail)
567 last = netem_skb_cb(sch->q.tail);
568 if (q->t_root.rb_node) {
569 struct sk_buff *t_skb;
570 struct netem_skb_cb *t_last;
571
572 t_skb = skb_rb_last(&q->t_root);
573 t_last = netem_skb_cb(t_skb);
574 if (!last ||
575 t_last->time_to_send > last->time_to_send)
576 last = t_last;
577 }
578 if (q->t_tail) {
579 struct netem_skb_cb *t_last =
580 netem_skb_cb(q->t_tail);
581
582 if (!last ||
583 t_last->time_to_send > last->time_to_send)
584 last = t_last;
585 }
586
587 if (last) {
588 /*
589 * Last packet in queue is reference point (now),
590 * calculate this time bonus and subtract
591 * from delay.
592 */
593 delay -= last->time_to_send - now;
594 delay = max_t(s64, 0, delay);
595 now = last->time_to_send;
596 }
597
598 delay += packet_time_ns(qdisc_pkt_len(skb), q);
599 }
600
601 cb->time_to_send = now + delay;
602 ++q->counter;
603 tfifo_enqueue(skb, sch);
604 } else {
605 /*
606 * Do re-ordering by putting one out of N packets at the front
607 * of the queue.
608 */
609 cb->time_to_send = ktime_get_ns();
610 q->counter = 0;
611
612 __qdisc_enqueue_head(skb, &sch->q);
613 sch->qstats.requeues++;
614 }
615
616finish_segs:
617 if (skb2)
618 __qdisc_drop(skb2, to_free);
619
620 if (segs) {
621 unsigned int len, last_len;
622 int rc, nb;
623
624 len = skb ? skb->len : 0;
625 nb = skb ? 1 : 0;
626
627 while (segs) {
628 skb2 = segs->next;
629 skb_mark_not_on_list(segs);
630 qdisc_skb_cb(segs)->pkt_len = segs->len;
631 last_len = segs->len;
632 rc = qdisc_enqueue(segs, sch, to_free);
633 if (rc != NET_XMIT_SUCCESS) {
634 if (net_xmit_drop_count(rc))
635 qdisc_qstats_drop(sch);
636 } else {
637 nb++;
638 len += last_len;
639 }
640 segs = skb2;
641 }
642 /* Parent qdiscs accounted for 1 skb of size @prev_len */
643 qdisc_tree_reduce_backlog(sch, -(nb - 1), -(len - prev_len));
644 } else if (!skb) {
645 return NET_XMIT_DROP;
646 }
647 return NET_XMIT_SUCCESS;
648}
649
650/* Delay the next round with a new future slot with a
651 * correct number of bytes and packets.
652 */
653
654static void get_slot_next(struct netem_sched_data *q, u64 now)
655{
656 s64 next_delay;
657
658 if (!q->slot_dist)
659 next_delay = q->slot_config.min_delay +
660 (get_random_u32() *
661 (q->slot_config.max_delay -
662 q->slot_config.min_delay) >> 32);
663 else
664 next_delay = tabledist(q->slot_config.dist_delay,
665 (s32)(q->slot_config.dist_jitter),
666 NULL, &q->prng, q->slot_dist);
667
668 q->slot.slot_next = now + next_delay;
669 q->slot.packets_left = q->slot_config.max_packets;
670 q->slot.bytes_left = q->slot_config.max_bytes;
671}
672
673static struct sk_buff *netem_peek(struct netem_sched_data *q)
674{
675 struct sk_buff *skb = skb_rb_first(&q->t_root);
676 u64 t1, t2;
677
678 if (!skb)
679 return q->t_head;
680 if (!q->t_head)
681 return skb;
682
683 t1 = netem_skb_cb(skb)->time_to_send;
684 t2 = netem_skb_cb(q->t_head)->time_to_send;
685 if (t1 < t2)
686 return skb;
687 return q->t_head;
688}
689
690static void netem_erase_head(struct netem_sched_data *q, struct sk_buff *skb)
691{
692 if (skb == q->t_head) {
693 q->t_head = skb->next;
694 if (!q->t_head)
695 q->t_tail = NULL;
696 } else {
697 rb_erase(&skb->rbnode, &q->t_root);
698 }
699}
700
701static struct sk_buff *netem_dequeue(struct Qdisc *sch)
702{
703 struct netem_sched_data *q = qdisc_priv(sch);
704 struct sk_buff *skb;
705
706tfifo_dequeue:
707 skb = __qdisc_dequeue_head(&sch->q);
708 if (skb) {
709deliver:
710 qdisc_qstats_backlog_dec(sch, skb);
711 qdisc_bstats_update(sch, skb);
712 return skb;
713 }
714 skb = netem_peek(q);
715 if (skb) {
716 u64 time_to_send;
717 u64 now = ktime_get_ns();
718
719 /* if more time remaining? */
720 time_to_send = netem_skb_cb(skb)->time_to_send;
721 if (q->slot.slot_next && q->slot.slot_next < time_to_send)
722 get_slot_next(q, now);
723
724 if (time_to_send <= now && q->slot.slot_next <= now) {
725 netem_erase_head(q, skb);
726 q->t_len--;
727 skb->next = NULL;
728 skb->prev = NULL;
729 /* skb->dev shares skb->rbnode area,
730 * we need to restore its value.
731 */
732 skb->dev = qdisc_dev(sch);
733
734 if (q->slot.slot_next) {
735 q->slot.packets_left--;
736 q->slot.bytes_left -= qdisc_pkt_len(skb);
737 if (q->slot.packets_left <= 0 ||
738 q->slot.bytes_left <= 0)
739 get_slot_next(q, now);
740 }
741
742 if (q->qdisc) {
743 unsigned int pkt_len = qdisc_pkt_len(skb);
744 struct sk_buff *to_free = NULL;
745 int err;
746
747 err = qdisc_enqueue(skb, q->qdisc, &to_free);
748 kfree_skb_list(to_free);
749 if (err != NET_XMIT_SUCCESS) {
750 if (net_xmit_drop_count(err))
751 qdisc_qstats_drop(sch);
752 sch->qstats.backlog -= pkt_len;
753 sch->q.qlen--;
754 qdisc_tree_reduce_backlog(sch, 1, pkt_len);
755 }
756 goto tfifo_dequeue;
757 }
758 sch->q.qlen--;
759 goto deliver;
760 }
761
762 if (q->qdisc) {
763 skb = q->qdisc->ops->dequeue(q->qdisc);
764 if (skb) {
765 sch->q.qlen--;
766 goto deliver;
767 }
768 }
769
770 qdisc_watchdog_schedule_ns(&q->watchdog,
771 max(time_to_send,
772 q->slot.slot_next));
773 }
774
775 if (q->qdisc) {
776 skb = q->qdisc->ops->dequeue(q->qdisc);
777 if (skb) {
778 sch->q.qlen--;
779 goto deliver;
780 }
781 }
782 return NULL;
783}
784
785static void netem_reset(struct Qdisc *sch)
786{
787 struct netem_sched_data *q = qdisc_priv(sch);
788
789 qdisc_reset_queue(sch);
790 tfifo_reset(sch);
791 if (q->qdisc)
792 qdisc_reset(q->qdisc);
793 qdisc_watchdog_cancel(&q->watchdog);
794}
795
796static void dist_free(struct disttable *d)
797{
798 kvfree(d);
799}
800
801/*
802 * Distribution data is a variable size payload containing
803 * signed 16 bit values.
804 */
805
806static int get_dist_table(struct disttable **tbl, const struct nlattr *attr)
807{
808 size_t n = nla_len(attr)/sizeof(__s16);
809 const __s16 *data = nla_data(attr);
810 struct disttable *d;
811 int i;
812
813 if (!n || n > NETEM_DIST_MAX)
814 return -EINVAL;
815
816 d = kvmalloc(struct_size(d, table, n), GFP_KERNEL);
817 if (!d)
818 return -ENOMEM;
819
820 d->size = n;
821 for (i = 0; i < n; i++)
822 d->table[i] = data[i];
823
824 *tbl = d;
825 return 0;
826}
827
828static void get_slot(struct netem_sched_data *q, const struct nlattr *attr)
829{
830 const struct tc_netem_slot *c = nla_data(attr);
831
832 q->slot_config = *c;
833 if (q->slot_config.max_packets == 0)
834 q->slot_config.max_packets = INT_MAX;
835 if (q->slot_config.max_bytes == 0)
836 q->slot_config.max_bytes = INT_MAX;
837
838 /* capping dist_jitter to the range acceptable by tabledist() */
839 q->slot_config.dist_jitter = min_t(__s64, INT_MAX, abs(q->slot_config.dist_jitter));
840
841 q->slot.packets_left = q->slot_config.max_packets;
842 q->slot.bytes_left = q->slot_config.max_bytes;
843 if (q->slot_config.min_delay | q->slot_config.max_delay |
844 q->slot_config.dist_jitter)
845 q->slot.slot_next = ktime_get_ns();
846 else
847 q->slot.slot_next = 0;
848}
849
850static void get_correlation(struct netem_sched_data *q, const struct nlattr *attr)
851{
852 const struct tc_netem_corr *c = nla_data(attr);
853
854 init_crandom(&q->delay_cor, c->delay_corr);
855 init_crandom(&q->loss_cor, c->loss_corr);
856 init_crandom(&q->dup_cor, c->dup_corr);
857}
858
859static void get_reorder(struct netem_sched_data *q, const struct nlattr *attr)
860{
861 const struct tc_netem_reorder *r = nla_data(attr);
862
863 q->reorder = r->probability;
864 init_crandom(&q->reorder_cor, r->correlation);
865}
866
867static void get_corrupt(struct netem_sched_data *q, const struct nlattr *attr)
868{
869 const struct tc_netem_corrupt *r = nla_data(attr);
870
871 q->corrupt = r->probability;
872 init_crandom(&q->corrupt_cor, r->correlation);
873}
874
875static void get_rate(struct netem_sched_data *q, const struct nlattr *attr)
876{
877 const struct tc_netem_rate *r = nla_data(attr);
878
879 q->rate = r->rate;
880 q->packet_overhead = r->packet_overhead;
881 q->cell_size = r->cell_size;
882 q->cell_overhead = r->cell_overhead;
883 if (q->cell_size)
884 q->cell_size_reciprocal = reciprocal_value(q->cell_size);
885 else
886 q->cell_size_reciprocal = (struct reciprocal_value) { 0 };
887}
888
889static int get_loss_clg(struct netem_sched_data *q, const struct nlattr *attr)
890{
891 const struct nlattr *la;
892 int rem;
893
894 nla_for_each_nested(la, attr, rem) {
895 u16 type = nla_type(la);
896
897 switch (type) {
898 case NETEM_LOSS_GI: {
899 const struct tc_netem_gimodel *gi = nla_data(la);
900
901 if (nla_len(la) < sizeof(struct tc_netem_gimodel)) {
902 pr_info("netem: incorrect gi model size\n");
903 return -EINVAL;
904 }
905
906 q->loss_model = CLG_4_STATES;
907
908 q->clg.state = TX_IN_GAP_PERIOD;
909 q->clg.a1 = gi->p13;
910 q->clg.a2 = gi->p31;
911 q->clg.a3 = gi->p32;
912 q->clg.a4 = gi->p14;
913 q->clg.a5 = gi->p23;
914 break;
915 }
916
917 case NETEM_LOSS_GE: {
918 const struct tc_netem_gemodel *ge = nla_data(la);
919
920 if (nla_len(la) < sizeof(struct tc_netem_gemodel)) {
921 pr_info("netem: incorrect ge model size\n");
922 return -EINVAL;
923 }
924
925 q->loss_model = CLG_GILB_ELL;
926 q->clg.state = GOOD_STATE;
927 q->clg.a1 = ge->p;
928 q->clg.a2 = ge->r;
929 q->clg.a3 = ge->h;
930 q->clg.a4 = ge->k1;
931 break;
932 }
933
934 default:
935 pr_info("netem: unknown loss type %u\n", type);
936 return -EINVAL;
937 }
938 }
939
940 return 0;
941}
942
943static const struct nla_policy netem_policy[TCA_NETEM_MAX + 1] = {
944 [TCA_NETEM_CORR] = { .len = sizeof(struct tc_netem_corr) },
945 [TCA_NETEM_REORDER] = { .len = sizeof(struct tc_netem_reorder) },
946 [TCA_NETEM_CORRUPT] = { .len = sizeof(struct tc_netem_corrupt) },
947 [TCA_NETEM_RATE] = { .len = sizeof(struct tc_netem_rate) },
948 [TCA_NETEM_LOSS] = { .type = NLA_NESTED },
949 [TCA_NETEM_ECN] = { .type = NLA_U32 },
950 [TCA_NETEM_RATE64] = { .type = NLA_U64 },
951 [TCA_NETEM_LATENCY64] = { .type = NLA_S64 },
952 [TCA_NETEM_JITTER64] = { .type = NLA_S64 },
953 [TCA_NETEM_SLOT] = { .len = sizeof(struct tc_netem_slot) },
954 [TCA_NETEM_PRNG_SEED] = { .type = NLA_U64 },
955};
956
957static int parse_attr(struct nlattr *tb[], int maxtype, struct nlattr *nla,
958 const struct nla_policy *policy, int len)
959{
960 int nested_len = nla_len(nla) - NLA_ALIGN(len);
961
962 if (nested_len < 0) {
963 pr_info("netem: invalid attributes len %d\n", nested_len);
964 return -EINVAL;
965 }
966
967 if (nested_len >= nla_attr_size(0))
968 return nla_parse_deprecated(tb, maxtype,
969 nla_data(nla) + NLA_ALIGN(len),
970 nested_len, policy, NULL);
971
972 memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
973 return 0;
974}
975
976/* Parse netlink message to set options */
977static int netem_change(struct Qdisc *sch, struct nlattr *opt,
978 struct netlink_ext_ack *extack)
979{
980 struct netem_sched_data *q = qdisc_priv(sch);
981 struct nlattr *tb[TCA_NETEM_MAX + 1];
982 struct disttable *delay_dist = NULL;
983 struct disttable *slot_dist = NULL;
984 struct tc_netem_qopt *qopt;
985 struct clgstate old_clg;
986 int old_loss_model = CLG_RANDOM;
987 int ret;
988
989 qopt = nla_data(opt);
990 ret = parse_attr(tb, TCA_NETEM_MAX, opt, netem_policy, sizeof(*qopt));
991 if (ret < 0)
992 return ret;
993
994 if (tb[TCA_NETEM_DELAY_DIST]) {
995 ret = get_dist_table(&delay_dist, tb[TCA_NETEM_DELAY_DIST]);
996 if (ret)
997 goto table_free;
998 }
999
1000 if (tb[TCA_NETEM_SLOT_DIST]) {
1001 ret = get_dist_table(&slot_dist, tb[TCA_NETEM_SLOT_DIST]);
1002 if (ret)
1003 goto table_free;
1004 }
1005
1006 sch_tree_lock(sch);
1007 /* backup q->clg and q->loss_model */
1008 old_clg = q->clg;
1009 old_loss_model = q->loss_model;
1010
1011 if (tb[TCA_NETEM_LOSS]) {
1012 ret = get_loss_clg(q, tb[TCA_NETEM_LOSS]);
1013 if (ret) {
1014 q->loss_model = old_loss_model;
1015 q->clg = old_clg;
1016 goto unlock;
1017 }
1018 } else {
1019 q->loss_model = CLG_RANDOM;
1020 }
1021
1022 if (delay_dist)
1023 swap(q->delay_dist, delay_dist);
1024 if (slot_dist)
1025 swap(q->slot_dist, slot_dist);
1026 sch->limit = qopt->limit;
1027
1028 q->latency = PSCHED_TICKS2NS(qopt->latency);
1029 q->jitter = PSCHED_TICKS2NS(qopt->jitter);
1030 q->limit = qopt->limit;
1031 q->gap = qopt->gap;
1032 q->counter = 0;
1033 q->loss = qopt->loss;
1034 q->duplicate = qopt->duplicate;
1035
1036 /* for compatibility with earlier versions.
1037 * if gap is set, need to assume 100% probability
1038 */
1039 if (q->gap)
1040 q->reorder = ~0;
1041
1042 if (tb[TCA_NETEM_CORR])
1043 get_correlation(q, tb[TCA_NETEM_CORR]);
1044
1045 if (tb[TCA_NETEM_REORDER])
1046 get_reorder(q, tb[TCA_NETEM_REORDER]);
1047
1048 if (tb[TCA_NETEM_CORRUPT])
1049 get_corrupt(q, tb[TCA_NETEM_CORRUPT]);
1050
1051 if (tb[TCA_NETEM_RATE])
1052 get_rate(q, tb[TCA_NETEM_RATE]);
1053
1054 if (tb[TCA_NETEM_RATE64])
1055 q->rate = max_t(u64, q->rate,
1056 nla_get_u64(tb[TCA_NETEM_RATE64]));
1057
1058 if (tb[TCA_NETEM_LATENCY64])
1059 q->latency = nla_get_s64(tb[TCA_NETEM_LATENCY64]);
1060
1061 if (tb[TCA_NETEM_JITTER64])
1062 q->jitter = nla_get_s64(tb[TCA_NETEM_JITTER64]);
1063
1064 if (tb[TCA_NETEM_ECN])
1065 q->ecn = nla_get_u32(tb[TCA_NETEM_ECN]);
1066
1067 if (tb[TCA_NETEM_SLOT])
1068 get_slot(q, tb[TCA_NETEM_SLOT]);
1069
1070 /* capping jitter to the range acceptable by tabledist() */
1071 q->jitter = min_t(s64, abs(q->jitter), INT_MAX);
1072
1073 if (tb[TCA_NETEM_PRNG_SEED])
1074 q->prng.seed = nla_get_u64(tb[TCA_NETEM_PRNG_SEED]);
1075 else
1076 q->prng.seed = get_random_u64();
1077 prandom_seed_state(&q->prng.prng_state, q->prng.seed);
1078
1079unlock:
1080 sch_tree_unlock(sch);
1081
1082table_free:
1083 dist_free(delay_dist);
1084 dist_free(slot_dist);
1085 return ret;
1086}
1087
1088static int netem_init(struct Qdisc *sch, struct nlattr *opt,
1089 struct netlink_ext_ack *extack)
1090{
1091 struct netem_sched_data *q = qdisc_priv(sch);
1092 int ret;
1093
1094 qdisc_watchdog_init(&q->watchdog, sch);
1095
1096 if (!opt)
1097 return -EINVAL;
1098
1099 q->loss_model = CLG_RANDOM;
1100 ret = netem_change(sch, opt, extack);
1101 if (ret)
1102 pr_info("netem: change failed\n");
1103 return ret;
1104}
1105
1106static void netem_destroy(struct Qdisc *sch)
1107{
1108 struct netem_sched_data *q = qdisc_priv(sch);
1109
1110 qdisc_watchdog_cancel(&q->watchdog);
1111 if (q->qdisc)
1112 qdisc_put(q->qdisc);
1113 dist_free(q->delay_dist);
1114 dist_free(q->slot_dist);
1115}
1116
1117static int dump_loss_model(const struct netem_sched_data *q,
1118 struct sk_buff *skb)
1119{
1120 struct nlattr *nest;
1121
1122 nest = nla_nest_start_noflag(skb, TCA_NETEM_LOSS);
1123 if (nest == NULL)
1124 goto nla_put_failure;
1125
1126 switch (q->loss_model) {
1127 case CLG_RANDOM:
1128 /* legacy loss model */
1129 nla_nest_cancel(skb, nest);
1130 return 0; /* no data */
1131
1132 case CLG_4_STATES: {
1133 struct tc_netem_gimodel gi = {
1134 .p13 = q->clg.a1,
1135 .p31 = q->clg.a2,
1136 .p32 = q->clg.a3,
1137 .p14 = q->clg.a4,
1138 .p23 = q->clg.a5,
1139 };
1140
1141 if (nla_put(skb, NETEM_LOSS_GI, sizeof(gi), &gi))
1142 goto nla_put_failure;
1143 break;
1144 }
1145 case CLG_GILB_ELL: {
1146 struct tc_netem_gemodel ge = {
1147 .p = q->clg.a1,
1148 .r = q->clg.a2,
1149 .h = q->clg.a3,
1150 .k1 = q->clg.a4,
1151 };
1152
1153 if (nla_put(skb, NETEM_LOSS_GE, sizeof(ge), &ge))
1154 goto nla_put_failure;
1155 break;
1156 }
1157 }
1158
1159 nla_nest_end(skb, nest);
1160 return 0;
1161
1162nla_put_failure:
1163 nla_nest_cancel(skb, nest);
1164 return -1;
1165}
1166
1167static int netem_dump(struct Qdisc *sch, struct sk_buff *skb)
1168{
1169 const struct netem_sched_data *q = qdisc_priv(sch);
1170 struct nlattr *nla = (struct nlattr *) skb_tail_pointer(skb);
1171 struct tc_netem_qopt qopt;
1172 struct tc_netem_corr cor;
1173 struct tc_netem_reorder reorder;
1174 struct tc_netem_corrupt corrupt;
1175 struct tc_netem_rate rate;
1176 struct tc_netem_slot slot;
1177
1178 qopt.latency = min_t(psched_time_t, PSCHED_NS2TICKS(q->latency),
1179 UINT_MAX);
1180 qopt.jitter = min_t(psched_time_t, PSCHED_NS2TICKS(q->jitter),
1181 UINT_MAX);
1182 qopt.limit = q->limit;
1183 qopt.loss = q->loss;
1184 qopt.gap = q->gap;
1185 qopt.duplicate = q->duplicate;
1186 if (nla_put(skb, TCA_OPTIONS, sizeof(qopt), &qopt))
1187 goto nla_put_failure;
1188
1189 if (nla_put(skb, TCA_NETEM_LATENCY64, sizeof(q->latency), &q->latency))
1190 goto nla_put_failure;
1191
1192 if (nla_put(skb, TCA_NETEM_JITTER64, sizeof(q->jitter), &q->jitter))
1193 goto nla_put_failure;
1194
1195 cor.delay_corr = q->delay_cor.rho;
1196 cor.loss_corr = q->loss_cor.rho;
1197 cor.dup_corr = q->dup_cor.rho;
1198 if (nla_put(skb, TCA_NETEM_CORR, sizeof(cor), &cor))
1199 goto nla_put_failure;
1200
1201 reorder.probability = q->reorder;
1202 reorder.correlation = q->reorder_cor.rho;
1203 if (nla_put(skb, TCA_NETEM_REORDER, sizeof(reorder), &reorder))
1204 goto nla_put_failure;
1205
1206 corrupt.probability = q->corrupt;
1207 corrupt.correlation = q->corrupt_cor.rho;
1208 if (nla_put(skb, TCA_NETEM_CORRUPT, sizeof(corrupt), &corrupt))
1209 goto nla_put_failure;
1210
1211 if (q->rate >= (1ULL << 32)) {
1212 if (nla_put_u64_64bit(skb, TCA_NETEM_RATE64, q->rate,
1213 TCA_NETEM_PAD))
1214 goto nla_put_failure;
1215 rate.rate = ~0U;
1216 } else {
1217 rate.rate = q->rate;
1218 }
1219 rate.packet_overhead = q->packet_overhead;
1220 rate.cell_size = q->cell_size;
1221 rate.cell_overhead = q->cell_overhead;
1222 if (nla_put(skb, TCA_NETEM_RATE, sizeof(rate), &rate))
1223 goto nla_put_failure;
1224
1225 if (q->ecn && nla_put_u32(skb, TCA_NETEM_ECN, q->ecn))
1226 goto nla_put_failure;
1227
1228 if (dump_loss_model(q, skb) != 0)
1229 goto nla_put_failure;
1230
1231 if (q->slot_config.min_delay | q->slot_config.max_delay |
1232 q->slot_config.dist_jitter) {
1233 slot = q->slot_config;
1234 if (slot.max_packets == INT_MAX)
1235 slot.max_packets = 0;
1236 if (slot.max_bytes == INT_MAX)
1237 slot.max_bytes = 0;
1238 if (nla_put(skb, TCA_NETEM_SLOT, sizeof(slot), &slot))
1239 goto nla_put_failure;
1240 }
1241
1242 if (nla_put_u64_64bit(skb, TCA_NETEM_PRNG_SEED, q->prng.seed,
1243 TCA_NETEM_PAD))
1244 goto nla_put_failure;
1245
1246 return nla_nest_end(skb, nla);
1247
1248nla_put_failure:
1249 nlmsg_trim(skb, nla);
1250 return -1;
1251}
1252
1253static int netem_dump_class(struct Qdisc *sch, unsigned long cl,
1254 struct sk_buff *skb, struct tcmsg *tcm)
1255{
1256 struct netem_sched_data *q = qdisc_priv(sch);
1257
1258 if (cl != 1 || !q->qdisc) /* only one class */
1259 return -ENOENT;
1260
1261 tcm->tcm_handle |= TC_H_MIN(1);
1262 tcm->tcm_info = q->qdisc->handle;
1263
1264 return 0;
1265}
1266
1267static int netem_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
1268 struct Qdisc **old, struct netlink_ext_ack *extack)
1269{
1270 struct netem_sched_data *q = qdisc_priv(sch);
1271
1272 *old = qdisc_replace(sch, new, &q->qdisc);
1273 return 0;
1274}
1275
1276static struct Qdisc *netem_leaf(struct Qdisc *sch, unsigned long arg)
1277{
1278 struct netem_sched_data *q = qdisc_priv(sch);
1279 return q->qdisc;
1280}
1281
1282static unsigned long netem_find(struct Qdisc *sch, u32 classid)
1283{
1284 return 1;
1285}
1286
1287static void netem_walk(struct Qdisc *sch, struct qdisc_walker *walker)
1288{
1289 if (!walker->stop) {
1290 if (!tc_qdisc_stats_dump(sch, 1, walker))
1291 return;
1292 }
1293}
1294
1295static const struct Qdisc_class_ops netem_class_ops = {
1296 .graft = netem_graft,
1297 .leaf = netem_leaf,
1298 .find = netem_find,
1299 .walk = netem_walk,
1300 .dump = netem_dump_class,
1301};
1302
1303static struct Qdisc_ops netem_qdisc_ops __read_mostly = {
1304 .id = "netem",
1305 .cl_ops = &netem_class_ops,
1306 .priv_size = sizeof(struct netem_sched_data),
1307 .enqueue = netem_enqueue,
1308 .dequeue = netem_dequeue,
1309 .peek = qdisc_peek_dequeued,
1310 .init = netem_init,
1311 .reset = netem_reset,
1312 .destroy = netem_destroy,
1313 .change = netem_change,
1314 .dump = netem_dump,
1315 .owner = THIS_MODULE,
1316};
1317MODULE_ALIAS_NET_SCH("netem");
1318
1319
1320static int __init netem_module_init(void)
1321{
1322 pr_info("netem: version " VERSION "\n");
1323 return register_qdisc(&netem_qdisc_ops);
1324}
1325static void __exit netem_module_exit(void)
1326{
1327 unregister_qdisc(&netem_qdisc_ops);
1328}
1329module_init(netem_module_init)
1330module_exit(netem_module_exit)
1331MODULE_LICENSE("GPL");
1332MODULE_DESCRIPTION("Network characteristics emulator qdisc");