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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#include <linux/rbtree.h>
27
28#include <net/netlink.h>
29#include <net/pkt_sched.h>
30#include <net/inet_ecn.h>
31
32#define VERSION "1.3"
33
34/* Network Emulation Queuing algorithm.
35 ====================================
36
37 Sources: [1] Mark Carson, Darrin Santay, "NIST Net - A Linux-based
38 Network Emulation Tool
39 [2] Luigi Rizzo, DummyNet for FreeBSD
40
41 ----------------------------------------------------------------
42
43 This started out as a simple way to delay outgoing packets to
44 test TCP but has grown to include most of the functionality
45 of a full blown network emulator like NISTnet. It can delay
46 packets and add random jitter (and correlation). The random
47 distribution can be loaded from a table as well to provide
48 normal, Pareto, or experimental curves. Packet loss,
49 duplication, and reordering can also be emulated.
50
51 This qdisc does not do classification that can be handled in
52 layering other disciplines. It does not need to do bandwidth
53 control either since that can be handled by using token
54 bucket or other rate control.
55
56 Correlated Loss Generator models
57
58 Added generation of correlated loss according to the
59 "Gilbert-Elliot" model, a 4-state markov model.
60
61 References:
62 [1] NetemCLG Home http://netgroup.uniroma2.it/NetemCLG
63 [2] S. Salsano, F. Ludovici, A. Ordine, "Definition of a general
64 and intuitive loss model for packet networks and its implementation
65 in the Netem module in the Linux kernel", available in [1]
66
67 Authors: Stefano Salsano <stefano.salsano at uniroma2.it
68 Fabio Ludovici <fabio.ludovici at yahoo.it>
69*/
70
71struct netem_sched_data {
72 /* internal t(ime)fifo qdisc uses t_root and sch->limit */
73 struct rb_root t_root;
74
75 /* optional qdisc for classful handling (NULL at netem init) */
76 struct Qdisc *qdisc;
77
78 struct qdisc_watchdog watchdog;
79
80 psched_tdiff_t latency;
81 psched_tdiff_t jitter;
82
83 u32 loss;
84 u32 ecn;
85 u32 limit;
86 u32 counter;
87 u32 gap;
88 u32 duplicate;
89 u32 reorder;
90 u32 corrupt;
91 u64 rate;
92 s32 packet_overhead;
93 u32 cell_size;
94 struct reciprocal_value cell_size_reciprocal;
95 s32 cell_overhead;
96
97 struct crndstate {
98 u32 last;
99 u32 rho;
100 } delay_cor, loss_cor, dup_cor, reorder_cor, corrupt_cor;
101
102 struct disttable {
103 u32 size;
104 s16 table[0];
105 } *delay_dist;
106
107 enum {
108 CLG_RANDOM,
109 CLG_4_STATES,
110 CLG_GILB_ELL,
111 } loss_model;
112
113 enum {
114 TX_IN_GAP_PERIOD = 1,
115 TX_IN_BURST_PERIOD,
116 LOST_IN_GAP_PERIOD,
117 LOST_IN_BURST_PERIOD,
118 } _4_state_model;
119
120 enum {
121 GOOD_STATE = 1,
122 BAD_STATE,
123 } GE_state_model;
124
125 /* Correlated Loss Generation models */
126 struct clgstate {
127 /* state of the Markov chain */
128 u8 state;
129
130 /* 4-states and Gilbert-Elliot models */
131 u32 a1; /* p13 for 4-states or p for GE */
132 u32 a2; /* p31 for 4-states or r for GE */
133 u32 a3; /* p32 for 4-states or h for GE */
134 u32 a4; /* p14 for 4-states or 1-k for GE */
135 u32 a5; /* p23 used only in 4-states */
136 } clg;
137
138};
139
140/* Time stamp put into socket buffer control block
141 * Only valid when skbs are in our internal t(ime)fifo queue.
142 */
143struct netem_skb_cb {
144 psched_time_t time_to_send;
145 ktime_t tstamp_save;
146};
147
148/* Because space in skb->cb[] is tight, netem overloads skb->next/prev/tstamp
149 * to hold a rb_node structure.
150 *
151 * If struct sk_buff layout is changed, the following checks will complain.
152 */
153static struct rb_node *netem_rb_node(struct sk_buff *skb)
154{
155 BUILD_BUG_ON(offsetof(struct sk_buff, next) != 0);
156 BUILD_BUG_ON(offsetof(struct sk_buff, prev) !=
157 offsetof(struct sk_buff, next) + sizeof(skb->next));
158 BUILD_BUG_ON(offsetof(struct sk_buff, tstamp) !=
159 offsetof(struct sk_buff, prev) + sizeof(skb->prev));
160 BUILD_BUG_ON(sizeof(struct rb_node) > sizeof(skb->next) +
161 sizeof(skb->prev) +
162 sizeof(skb->tstamp));
163 return (struct rb_node *)&skb->next;
164}
165
166static struct sk_buff *netem_rb_to_skb(struct rb_node *rb)
167{
168 return (struct sk_buff *)rb;
169}
170
171static inline struct netem_skb_cb *netem_skb_cb(struct sk_buff *skb)
172{
173 /* we assume we can use skb next/prev/tstamp as storage for rb_node */
174 qdisc_cb_private_validate(skb, sizeof(struct netem_skb_cb));
175 return (struct netem_skb_cb *)qdisc_skb_cb(skb)->data;
176}
177
178/* init_crandom - initialize correlated random number generator
179 * Use entropy source for initial seed.
180 */
181static void init_crandom(struct crndstate *state, unsigned long rho)
182{
183 state->rho = rho;
184 state->last = prandom_u32();
185}
186
187/* get_crandom - correlated random number generator
188 * Next number depends on last value.
189 * rho is scaled to avoid floating point.
190 */
191static u32 get_crandom(struct crndstate *state)
192{
193 u64 value, rho;
194 unsigned long answer;
195
196 if (state->rho == 0) /* no correlation */
197 return prandom_u32();
198
199 value = prandom_u32();
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();
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_BURST_PERIOD => isolated losses within a gap period
222 * LOST_IN_GAP_PERIOD => lost packets within a burst period
223 * TX_IN_GAP_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_BURST_PERIOD;
229 return true;
230 } else if (clg->a4 < rnd && rnd < clg->a1 + clg->a4) {
231 clg->state = LOST_IN_GAP_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_GAP_PERIOD;
241 return true;
242 } else {
243 clg->state = TX_IN_BURST_PERIOD;
244 }
245
246 break;
247 case LOST_IN_GAP_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_GAP_PERIOD;
254 return true;
255 }
256 break;
257 case LOST_IN_BURST_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
279 switch (clg->state) {
280 case GOOD_STATE:
281 if (prandom_u32() < clg->a1)
282 clg->state = BAD_STATE;
283 if (prandom_u32() < clg->a4)
284 return true;
285 break;
286 case BAD_STATE:
287 if (prandom_u32() < clg->a2)
288 clg->state = GOOD_STATE;
289 if (prandom_u32() > clg->a3)
290 return true;
291 }
292
293 return false;
294}
295
296static bool loss_event(struct netem_sched_data *q)
297{
298 switch (q->loss_model) {
299 case CLG_RANDOM:
300 /* Random packet drop 0 => none, ~0 => all */
301 return q->loss && q->loss >= get_crandom(&q->loss_cor);
302
303 case CLG_4_STATES:
304 /* 4state loss model algorithm (used also for GI model)
305 * Extracts a value from the markov 4 state loss generator,
306 * if it is 1 drops a packet and if needed writes the event in
307 * the kernel logs
308 */
309 return loss_4state(q);
310
311 case CLG_GILB_ELL:
312 /* Gilbert-Elliot loss model algorithm
313 * Extracts a value from the Gilbert-Elliot loss generator,
314 * if it is 1 drops a packet and if needed writes the event in
315 * the kernel logs
316 */
317 return loss_gilb_ell(q);
318 }
319
320 return false; /* not reached */
321}
322
323
324/* tabledist - return a pseudo-randomly distributed value with mean mu and
325 * std deviation sigma. Uses table lookup to approximate the desired
326 * distribution, and a uniformly-distributed pseudo-random source.
327 */
328static psched_tdiff_t tabledist(psched_tdiff_t mu, psched_tdiff_t sigma,
329 struct crndstate *state,
330 const struct disttable *dist)
331{
332 psched_tdiff_t x;
333 long t;
334 u32 rnd;
335
336 if (sigma == 0)
337 return mu;
338
339 rnd = get_crandom(state);
340
341 /* default uniform distribution */
342 if (dist == NULL)
343 return (rnd % (2*sigma)) - sigma + mu;
344
345 t = dist->table[rnd % dist->size];
346 x = (sigma % NETEM_DIST_SCALE) * t;
347 if (x >= 0)
348 x += NETEM_DIST_SCALE/2;
349 else
350 x -= NETEM_DIST_SCALE/2;
351
352 return x / NETEM_DIST_SCALE + (sigma / NETEM_DIST_SCALE) * t + mu;
353}
354
355static psched_time_t packet_len_2_sched_time(unsigned int len, struct netem_sched_data *q)
356{
357 u64 ticks;
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 ticks = (u64)len * NSEC_PER_SEC;
370
371 do_div(ticks, q->rate);
372 return PSCHED_NS2TICKS(ticks);
373}
374
375static void tfifo_reset(struct Qdisc *sch)
376{
377 struct netem_sched_data *q = qdisc_priv(sch);
378 struct rb_node *p;
379
380 while ((p = rb_first(&q->t_root))) {
381 struct sk_buff *skb = netem_rb_to_skb(p);
382
383 rb_erase(p, &q->t_root);
384 skb->next = NULL;
385 skb->prev = NULL;
386 kfree_skb(skb);
387 }
388}
389
390static void tfifo_enqueue(struct sk_buff *nskb, struct Qdisc *sch)
391{
392 struct netem_sched_data *q = qdisc_priv(sch);
393 psched_time_t tnext = netem_skb_cb(nskb)->time_to_send;
394 struct rb_node **p = &q->t_root.rb_node, *parent = NULL;
395
396 while (*p) {
397 struct sk_buff *skb;
398
399 parent = *p;
400 skb = netem_rb_to_skb(parent);
401 if (tnext >= netem_skb_cb(skb)->time_to_send)
402 p = &parent->rb_right;
403 else
404 p = &parent->rb_left;
405 }
406 rb_link_node(netem_rb_node(nskb), parent, p);
407 rb_insert_color(netem_rb_node(nskb), &q->t_root);
408 sch->q.qlen++;
409}
410
411/*
412 * Insert one skb into qdisc.
413 * Note: parent depends on return value to account for queue length.
414 * NET_XMIT_DROP: queue length didn't change.
415 * NET_XMIT_SUCCESS: one skb was queued.
416 */
417static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch)
418{
419 struct netem_sched_data *q = qdisc_priv(sch);
420 /* We don't fill cb now as skb_unshare() may invalidate it */
421 struct netem_skb_cb *cb;
422 struct sk_buff *skb2;
423 int count = 1;
424
425 /* Random duplication */
426 if (q->duplicate && q->duplicate >= get_crandom(&q->dup_cor))
427 ++count;
428
429 /* Drop packet? */
430 if (loss_event(q)) {
431 if (q->ecn && INET_ECN_set_ce(skb))
432 sch->qstats.drops++; /* mark packet */
433 else
434 --count;
435 }
436 if (count == 0) {
437 sch->qstats.drops++;
438 kfree_skb(skb);
439 return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
440 }
441
442 /* If a delay is expected, orphan the skb. (orphaning usually takes
443 * place at TX completion time, so _before_ the link transit delay)
444 */
445 if (q->latency || q->jitter)
446 skb_orphan_partial(skb);
447
448 /*
449 * If we need to duplicate packet, then re-insert at top of the
450 * qdisc tree, since parent queuer expects that only one
451 * skb will be queued.
452 */
453 if (count > 1 && (skb2 = skb_clone(skb, GFP_ATOMIC)) != NULL) {
454 struct Qdisc *rootq = qdisc_root(sch);
455 u32 dupsave = q->duplicate; /* prevent duplicating a dup... */
456 q->duplicate = 0;
457
458 qdisc_enqueue_root(skb2, rootq);
459 q->duplicate = dupsave;
460 }
461
462 /*
463 * Randomized packet corruption.
464 * Make copy if needed since we are modifying
465 * If packet is going to be hardware checksummed, then
466 * do it now in software before we mangle it.
467 */
468 if (q->corrupt && q->corrupt >= get_crandom(&q->corrupt_cor)) {
469 if (!(skb = skb_unshare(skb, GFP_ATOMIC)) ||
470 (skb->ip_summed == CHECKSUM_PARTIAL &&
471 skb_checksum_help(skb)))
472 return qdisc_drop(skb, sch);
473
474 skb->data[prandom_u32() % skb_headlen(skb)] ^=
475 1<<(prandom_u32() % 8);
476 }
477
478 if (unlikely(skb_queue_len(&sch->q) >= sch->limit))
479 return qdisc_reshape_fail(skb, sch);
480
481 sch->qstats.backlog += qdisc_pkt_len(skb);
482
483 cb = netem_skb_cb(skb);
484 if (q->gap == 0 || /* not doing reordering */
485 q->counter < q->gap - 1 || /* inside last reordering gap */
486 q->reorder < get_crandom(&q->reorder_cor)) {
487 psched_time_t now;
488 psched_tdiff_t delay;
489
490 delay = tabledist(q->latency, q->jitter,
491 &q->delay_cor, q->delay_dist);
492
493 now = psched_get_time();
494
495 if (q->rate) {
496 struct sk_buff *last;
497
498 if (!skb_queue_empty(&sch->q))
499 last = skb_peek_tail(&sch->q);
500 else
501 last = netem_rb_to_skb(rb_last(&q->t_root));
502 if (last) {
503 /*
504 * Last packet in queue is reference point (now),
505 * calculate this time bonus and subtract
506 * from delay.
507 */
508 delay -= netem_skb_cb(last)->time_to_send - now;
509 delay = max_t(psched_tdiff_t, 0, delay);
510 now = netem_skb_cb(last)->time_to_send;
511 }
512
513 delay += packet_len_2_sched_time(qdisc_pkt_len(skb), q);
514 }
515
516 cb->time_to_send = now + delay;
517 cb->tstamp_save = skb->tstamp;
518 ++q->counter;
519 tfifo_enqueue(skb, sch);
520 } else {
521 /*
522 * Do re-ordering by putting one out of N packets at the front
523 * of the queue.
524 */
525 cb->time_to_send = psched_get_time();
526 q->counter = 0;
527
528 __skb_queue_head(&sch->q, skb);
529 sch->qstats.requeues++;
530 }
531
532 return NET_XMIT_SUCCESS;
533}
534
535static unsigned int netem_drop(struct Qdisc *sch)
536{
537 struct netem_sched_data *q = qdisc_priv(sch);
538 unsigned int len;
539
540 len = qdisc_queue_drop(sch);
541
542 if (!len) {
543 struct rb_node *p = rb_first(&q->t_root);
544
545 if (p) {
546 struct sk_buff *skb = netem_rb_to_skb(p);
547
548 rb_erase(p, &q->t_root);
549 sch->q.qlen--;
550 skb->next = NULL;
551 skb->prev = NULL;
552 len = qdisc_pkt_len(skb);
553 sch->qstats.backlog -= len;
554 kfree_skb(skb);
555 }
556 }
557 if (!len && q->qdisc && q->qdisc->ops->drop)
558 len = q->qdisc->ops->drop(q->qdisc);
559 if (len)
560 sch->qstats.drops++;
561
562 return len;
563}
564
565static struct sk_buff *netem_dequeue(struct Qdisc *sch)
566{
567 struct netem_sched_data *q = qdisc_priv(sch);
568 struct sk_buff *skb;
569 struct rb_node *p;
570
571 if (qdisc_is_throttled(sch))
572 return NULL;
573
574tfifo_dequeue:
575 skb = __skb_dequeue(&sch->q);
576 if (skb) {
577deliver:
578 sch->qstats.backlog -= qdisc_pkt_len(skb);
579 qdisc_unthrottled(sch);
580 qdisc_bstats_update(sch, skb);
581 return skb;
582 }
583 p = rb_first(&q->t_root);
584 if (p) {
585 psched_time_t time_to_send;
586
587 skb = netem_rb_to_skb(p);
588
589 /* if more time remaining? */
590 time_to_send = netem_skb_cb(skb)->time_to_send;
591 if (time_to_send <= psched_get_time()) {
592 rb_erase(p, &q->t_root);
593
594 sch->q.qlen--;
595 skb->next = NULL;
596 skb->prev = NULL;
597 skb->tstamp = netem_skb_cb(skb)->tstamp_save;
598
599#ifdef CONFIG_NET_CLS_ACT
600 /*
601 * If it's at ingress let's pretend the delay is
602 * from the network (tstamp will be updated).
603 */
604 if (G_TC_FROM(skb->tc_verd) & AT_INGRESS)
605 skb->tstamp.tv64 = 0;
606#endif
607
608 if (q->qdisc) {
609 int err = qdisc_enqueue(skb, q->qdisc);
610
611 if (unlikely(err != NET_XMIT_SUCCESS)) {
612 if (net_xmit_drop_count(err)) {
613 sch->qstats.drops++;
614 qdisc_tree_decrease_qlen(sch, 1);
615 }
616 }
617 goto tfifo_dequeue;
618 }
619 goto deliver;
620 }
621
622 if (q->qdisc) {
623 skb = q->qdisc->ops->dequeue(q->qdisc);
624 if (skb)
625 goto deliver;
626 }
627 qdisc_watchdog_schedule(&q->watchdog, time_to_send);
628 }
629
630 if (q->qdisc) {
631 skb = q->qdisc->ops->dequeue(q->qdisc);
632 if (skb)
633 goto deliver;
634 }
635 return NULL;
636}
637
638static void netem_reset(struct Qdisc *sch)
639{
640 struct netem_sched_data *q = qdisc_priv(sch);
641
642 qdisc_reset_queue(sch);
643 tfifo_reset(sch);
644 if (q->qdisc)
645 qdisc_reset(q->qdisc);
646 qdisc_watchdog_cancel(&q->watchdog);
647}
648
649static void dist_free(struct disttable *d)
650{
651 if (d) {
652 if (is_vmalloc_addr(d))
653 vfree(d);
654 else
655 kfree(d);
656 }
657}
658
659/*
660 * Distribution data is a variable size payload containing
661 * signed 16 bit values.
662 */
663static int get_dist_table(struct Qdisc *sch, const struct nlattr *attr)
664{
665 struct netem_sched_data *q = qdisc_priv(sch);
666 size_t n = nla_len(attr)/sizeof(__s16);
667 const __s16 *data = nla_data(attr);
668 spinlock_t *root_lock;
669 struct disttable *d;
670 int i;
671 size_t s;
672
673 if (n > NETEM_DIST_MAX)
674 return -EINVAL;
675
676 s = sizeof(struct disttable) + n * sizeof(s16);
677 d = kmalloc(s, GFP_KERNEL | __GFP_NOWARN);
678 if (!d)
679 d = vmalloc(s);
680 if (!d)
681 return -ENOMEM;
682
683 d->size = n;
684 for (i = 0; i < n; i++)
685 d->table[i] = data[i];
686
687 root_lock = qdisc_root_sleeping_lock(sch);
688
689 spin_lock_bh(root_lock);
690 swap(q->delay_dist, d);
691 spin_unlock_bh(root_lock);
692
693 dist_free(d);
694 return 0;
695}
696
697static void get_correlation(struct netem_sched_data *q, const struct nlattr *attr)
698{
699 const struct tc_netem_corr *c = nla_data(attr);
700
701 init_crandom(&q->delay_cor, c->delay_corr);
702 init_crandom(&q->loss_cor, c->loss_corr);
703 init_crandom(&q->dup_cor, c->dup_corr);
704}
705
706static void get_reorder(struct netem_sched_data *q, const struct nlattr *attr)
707{
708 const struct tc_netem_reorder *r = nla_data(attr);
709
710 q->reorder = r->probability;
711 init_crandom(&q->reorder_cor, r->correlation);
712}
713
714static void get_corrupt(struct netem_sched_data *q, const struct nlattr *attr)
715{
716 const struct tc_netem_corrupt *r = nla_data(attr);
717
718 q->corrupt = r->probability;
719 init_crandom(&q->corrupt_cor, r->correlation);
720}
721
722static void get_rate(struct netem_sched_data *q, const struct nlattr *attr)
723{
724 const struct tc_netem_rate *r = nla_data(attr);
725
726 q->rate = r->rate;
727 q->packet_overhead = r->packet_overhead;
728 q->cell_size = r->cell_size;
729 q->cell_overhead = r->cell_overhead;
730 if (q->cell_size)
731 q->cell_size_reciprocal = reciprocal_value(q->cell_size);
732 else
733 q->cell_size_reciprocal = (struct reciprocal_value) { 0 };
734}
735
736static int get_loss_clg(struct netem_sched_data *q, const struct nlattr *attr)
737{
738 const struct nlattr *la;
739 int rem;
740
741 nla_for_each_nested(la, attr, rem) {
742 u16 type = nla_type(la);
743
744 switch (type) {
745 case NETEM_LOSS_GI: {
746 const struct tc_netem_gimodel *gi = nla_data(la);
747
748 if (nla_len(la) < sizeof(struct tc_netem_gimodel)) {
749 pr_info("netem: incorrect gi model size\n");
750 return -EINVAL;
751 }
752
753 q->loss_model = CLG_4_STATES;
754
755 q->clg.state = TX_IN_GAP_PERIOD;
756 q->clg.a1 = gi->p13;
757 q->clg.a2 = gi->p31;
758 q->clg.a3 = gi->p32;
759 q->clg.a4 = gi->p14;
760 q->clg.a5 = gi->p23;
761 break;
762 }
763
764 case NETEM_LOSS_GE: {
765 const struct tc_netem_gemodel *ge = nla_data(la);
766
767 if (nla_len(la) < sizeof(struct tc_netem_gemodel)) {
768 pr_info("netem: incorrect ge model size\n");
769 return -EINVAL;
770 }
771
772 q->loss_model = CLG_GILB_ELL;
773 q->clg.state = GOOD_STATE;
774 q->clg.a1 = ge->p;
775 q->clg.a2 = ge->r;
776 q->clg.a3 = ge->h;
777 q->clg.a4 = ge->k1;
778 break;
779 }
780
781 default:
782 pr_info("netem: unknown loss type %u\n", type);
783 return -EINVAL;
784 }
785 }
786
787 return 0;
788}
789
790static const struct nla_policy netem_policy[TCA_NETEM_MAX + 1] = {
791 [TCA_NETEM_CORR] = { .len = sizeof(struct tc_netem_corr) },
792 [TCA_NETEM_REORDER] = { .len = sizeof(struct tc_netem_reorder) },
793 [TCA_NETEM_CORRUPT] = { .len = sizeof(struct tc_netem_corrupt) },
794 [TCA_NETEM_RATE] = { .len = sizeof(struct tc_netem_rate) },
795 [TCA_NETEM_LOSS] = { .type = NLA_NESTED },
796 [TCA_NETEM_ECN] = { .type = NLA_U32 },
797 [TCA_NETEM_RATE64] = { .type = NLA_U64 },
798};
799
800static int parse_attr(struct nlattr *tb[], int maxtype, struct nlattr *nla,
801 const struct nla_policy *policy, int len)
802{
803 int nested_len = nla_len(nla) - NLA_ALIGN(len);
804
805 if (nested_len < 0) {
806 pr_info("netem: invalid attributes len %d\n", nested_len);
807 return -EINVAL;
808 }
809
810 if (nested_len >= nla_attr_size(0))
811 return nla_parse(tb, maxtype, nla_data(nla) + NLA_ALIGN(len),
812 nested_len, policy);
813
814 memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
815 return 0;
816}
817
818/* Parse netlink message to set options */
819static int netem_change(struct Qdisc *sch, struct nlattr *opt)
820{
821 struct netem_sched_data *q = qdisc_priv(sch);
822 struct nlattr *tb[TCA_NETEM_MAX + 1];
823 struct tc_netem_qopt *qopt;
824 struct clgstate old_clg;
825 int old_loss_model = CLG_RANDOM;
826 int ret;
827
828 if (opt == NULL)
829 return -EINVAL;
830
831 qopt = nla_data(opt);
832 ret = parse_attr(tb, TCA_NETEM_MAX, opt, netem_policy, sizeof(*qopt));
833 if (ret < 0)
834 return ret;
835
836 /* backup q->clg and q->loss_model */
837 old_clg = q->clg;
838 old_loss_model = q->loss_model;
839
840 if (tb[TCA_NETEM_LOSS]) {
841 ret = get_loss_clg(q, tb[TCA_NETEM_LOSS]);
842 if (ret) {
843 q->loss_model = old_loss_model;
844 return ret;
845 }
846 } else {
847 q->loss_model = CLG_RANDOM;
848 }
849
850 if (tb[TCA_NETEM_DELAY_DIST]) {
851 ret = get_dist_table(sch, tb[TCA_NETEM_DELAY_DIST]);
852 if (ret) {
853 /* recover clg and loss_model, in case of
854 * q->clg and q->loss_model were modified
855 * in get_loss_clg()
856 */
857 q->clg = old_clg;
858 q->loss_model = old_loss_model;
859 return ret;
860 }
861 }
862
863 sch->limit = qopt->limit;
864
865 q->latency = qopt->latency;
866 q->jitter = qopt->jitter;
867 q->limit = qopt->limit;
868 q->gap = qopt->gap;
869 q->counter = 0;
870 q->loss = qopt->loss;
871 q->duplicate = qopt->duplicate;
872
873 /* for compatibility with earlier versions.
874 * if gap is set, need to assume 100% probability
875 */
876 if (q->gap)
877 q->reorder = ~0;
878
879 if (tb[TCA_NETEM_CORR])
880 get_correlation(q, tb[TCA_NETEM_CORR]);
881
882 if (tb[TCA_NETEM_REORDER])
883 get_reorder(q, tb[TCA_NETEM_REORDER]);
884
885 if (tb[TCA_NETEM_CORRUPT])
886 get_corrupt(q, tb[TCA_NETEM_CORRUPT]);
887
888 if (tb[TCA_NETEM_RATE])
889 get_rate(q, tb[TCA_NETEM_RATE]);
890
891 if (tb[TCA_NETEM_RATE64])
892 q->rate = max_t(u64, q->rate,
893 nla_get_u64(tb[TCA_NETEM_RATE64]));
894
895 if (tb[TCA_NETEM_ECN])
896 q->ecn = nla_get_u32(tb[TCA_NETEM_ECN]);
897
898 return ret;
899}
900
901static int netem_init(struct Qdisc *sch, struct nlattr *opt)
902{
903 struct netem_sched_data *q = qdisc_priv(sch);
904 int ret;
905
906 if (!opt)
907 return -EINVAL;
908
909 qdisc_watchdog_init(&q->watchdog, sch);
910
911 q->loss_model = CLG_RANDOM;
912 ret = netem_change(sch, opt);
913 if (ret)
914 pr_info("netem: change failed\n");
915 return ret;
916}
917
918static void netem_destroy(struct Qdisc *sch)
919{
920 struct netem_sched_data *q = qdisc_priv(sch);
921
922 qdisc_watchdog_cancel(&q->watchdog);
923 if (q->qdisc)
924 qdisc_destroy(q->qdisc);
925 dist_free(q->delay_dist);
926}
927
928static int dump_loss_model(const struct netem_sched_data *q,
929 struct sk_buff *skb)
930{
931 struct nlattr *nest;
932
933 nest = nla_nest_start(skb, TCA_NETEM_LOSS);
934 if (nest == NULL)
935 goto nla_put_failure;
936
937 switch (q->loss_model) {
938 case CLG_RANDOM:
939 /* legacy loss model */
940 nla_nest_cancel(skb, nest);
941 return 0; /* no data */
942
943 case CLG_4_STATES: {
944 struct tc_netem_gimodel gi = {
945 .p13 = q->clg.a1,
946 .p31 = q->clg.a2,
947 .p32 = q->clg.a3,
948 .p14 = q->clg.a4,
949 .p23 = q->clg.a5,
950 };
951
952 if (nla_put(skb, NETEM_LOSS_GI, sizeof(gi), &gi))
953 goto nla_put_failure;
954 break;
955 }
956 case CLG_GILB_ELL: {
957 struct tc_netem_gemodel ge = {
958 .p = q->clg.a1,
959 .r = q->clg.a2,
960 .h = q->clg.a3,
961 .k1 = q->clg.a4,
962 };
963
964 if (nla_put(skb, NETEM_LOSS_GE, sizeof(ge), &ge))
965 goto nla_put_failure;
966 break;
967 }
968 }
969
970 nla_nest_end(skb, nest);
971 return 0;
972
973nla_put_failure:
974 nla_nest_cancel(skb, nest);
975 return -1;
976}
977
978static int netem_dump(struct Qdisc *sch, struct sk_buff *skb)
979{
980 const struct netem_sched_data *q = qdisc_priv(sch);
981 struct nlattr *nla = (struct nlattr *) skb_tail_pointer(skb);
982 struct tc_netem_qopt qopt;
983 struct tc_netem_corr cor;
984 struct tc_netem_reorder reorder;
985 struct tc_netem_corrupt corrupt;
986 struct tc_netem_rate rate;
987
988 qopt.latency = q->latency;
989 qopt.jitter = q->jitter;
990 qopt.limit = q->limit;
991 qopt.loss = q->loss;
992 qopt.gap = q->gap;
993 qopt.duplicate = q->duplicate;
994 if (nla_put(skb, TCA_OPTIONS, sizeof(qopt), &qopt))
995 goto nla_put_failure;
996
997 cor.delay_corr = q->delay_cor.rho;
998 cor.loss_corr = q->loss_cor.rho;
999 cor.dup_corr = q->dup_cor.rho;
1000 if (nla_put(skb, TCA_NETEM_CORR, sizeof(cor), &cor))
1001 goto nla_put_failure;
1002
1003 reorder.probability = q->reorder;
1004 reorder.correlation = q->reorder_cor.rho;
1005 if (nla_put(skb, TCA_NETEM_REORDER, sizeof(reorder), &reorder))
1006 goto nla_put_failure;
1007
1008 corrupt.probability = q->corrupt;
1009 corrupt.correlation = q->corrupt_cor.rho;
1010 if (nla_put(skb, TCA_NETEM_CORRUPT, sizeof(corrupt), &corrupt))
1011 goto nla_put_failure;
1012
1013 if (q->rate >= (1ULL << 32)) {
1014 if (nla_put_u64(skb, TCA_NETEM_RATE64, q->rate))
1015 goto nla_put_failure;
1016 rate.rate = ~0U;
1017 } else {
1018 rate.rate = q->rate;
1019 }
1020 rate.packet_overhead = q->packet_overhead;
1021 rate.cell_size = q->cell_size;
1022 rate.cell_overhead = q->cell_overhead;
1023 if (nla_put(skb, TCA_NETEM_RATE, sizeof(rate), &rate))
1024 goto nla_put_failure;
1025
1026 if (q->ecn && nla_put_u32(skb, TCA_NETEM_ECN, q->ecn))
1027 goto nla_put_failure;
1028
1029 if (dump_loss_model(q, skb) != 0)
1030 goto nla_put_failure;
1031
1032 return nla_nest_end(skb, nla);
1033
1034nla_put_failure:
1035 nlmsg_trim(skb, nla);
1036 return -1;
1037}
1038
1039static int netem_dump_class(struct Qdisc *sch, unsigned long cl,
1040 struct sk_buff *skb, struct tcmsg *tcm)
1041{
1042 struct netem_sched_data *q = qdisc_priv(sch);
1043
1044 if (cl != 1 || !q->qdisc) /* only one class */
1045 return -ENOENT;
1046
1047 tcm->tcm_handle |= TC_H_MIN(1);
1048 tcm->tcm_info = q->qdisc->handle;
1049
1050 return 0;
1051}
1052
1053static int netem_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
1054 struct Qdisc **old)
1055{
1056 struct netem_sched_data *q = qdisc_priv(sch);
1057
1058 sch_tree_lock(sch);
1059 *old = q->qdisc;
1060 q->qdisc = new;
1061 if (*old) {
1062 qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
1063 qdisc_reset(*old);
1064 }
1065 sch_tree_unlock(sch);
1066
1067 return 0;
1068}
1069
1070static struct Qdisc *netem_leaf(struct Qdisc *sch, unsigned long arg)
1071{
1072 struct netem_sched_data *q = qdisc_priv(sch);
1073 return q->qdisc;
1074}
1075
1076static unsigned long netem_get(struct Qdisc *sch, u32 classid)
1077{
1078 return 1;
1079}
1080
1081static void netem_put(struct Qdisc *sch, unsigned long arg)
1082{
1083}
1084
1085static void netem_walk(struct Qdisc *sch, struct qdisc_walker *walker)
1086{
1087 if (!walker->stop) {
1088 if (walker->count >= walker->skip)
1089 if (walker->fn(sch, 1, walker) < 0) {
1090 walker->stop = 1;
1091 return;
1092 }
1093 walker->count++;
1094 }
1095}
1096
1097static const struct Qdisc_class_ops netem_class_ops = {
1098 .graft = netem_graft,
1099 .leaf = netem_leaf,
1100 .get = netem_get,
1101 .put = netem_put,
1102 .walk = netem_walk,
1103 .dump = netem_dump_class,
1104};
1105
1106static struct Qdisc_ops netem_qdisc_ops __read_mostly = {
1107 .id = "netem",
1108 .cl_ops = &netem_class_ops,
1109 .priv_size = sizeof(struct netem_sched_data),
1110 .enqueue = netem_enqueue,
1111 .dequeue = netem_dequeue,
1112 .peek = qdisc_peek_dequeued,
1113 .drop = netem_drop,
1114 .init = netem_init,
1115 .reset = netem_reset,
1116 .destroy = netem_destroy,
1117 .change = netem_change,
1118 .dump = netem_dump,
1119 .owner = THIS_MODULE,
1120};
1121
1122
1123static int __init netem_module_init(void)
1124{
1125 pr_info("netem: version " VERSION "\n");
1126 return register_qdisc(&netem_qdisc_ops);
1127}
1128static void __exit netem_module_exit(void)
1129{
1130 unregister_qdisc(&netem_qdisc_ops);
1131}
1132module_init(netem_module_init)
1133module_exit(netem_module_exit)
1134MODULE_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/rtnetlink.h>
21#include <linux/reciprocal_div.h>
22#include <linux/rbtree.h>
23
24#include <net/netlink.h>
25#include <net/pkt_sched.h>
26#include <net/inet_ecn.h>
27
28#define VERSION "1.3"
29
30/* Network Emulation Queuing algorithm.
31 ====================================
32
33 Sources: [1] Mark Carson, Darrin Santay, "NIST Net - A Linux-based
34 Network Emulation Tool
35 [2] Luigi Rizzo, DummyNet for FreeBSD
36
37 ----------------------------------------------------------------
38
39 This started out as a simple way to delay outgoing packets to
40 test TCP but has grown to include most of the functionality
41 of a full blown network emulator like NISTnet. It can delay
42 packets and add random jitter (and correlation). The random
43 distribution can be loaded from a table as well to provide
44 normal, Pareto, or experimental curves. Packet loss,
45 duplication, and reordering can also be emulated.
46
47 This qdisc does not do classification that can be handled in
48 layering other disciplines. It does not need to do bandwidth
49 control either since that can be handled by using token
50 bucket or other rate control.
51
52 Correlated Loss Generator models
53
54 Added generation of correlated loss according to the
55 "Gilbert-Elliot" model, a 4-state markov model.
56
57 References:
58 [1] NetemCLG Home http://netgroup.uniroma2.it/NetemCLG
59 [2] S. Salsano, F. Ludovici, A. Ordine, "Definition of a general
60 and intuitive loss model for packet networks and its implementation
61 in the Netem module in the Linux kernel", available in [1]
62
63 Authors: Stefano Salsano <stefano.salsano at uniroma2.it
64 Fabio Ludovici <fabio.ludovici at yahoo.it>
65*/
66
67struct disttable {
68 u32 size;
69 s16 table[];
70};
71
72struct netem_sched_data {
73 /* internal t(ime)fifo qdisc uses t_root and sch->limit */
74 struct rb_root t_root;
75
76 /* a linear queue; reduces rbtree rebalancing when jitter is low */
77 struct sk_buff *t_head;
78 struct sk_buff *t_tail;
79
80 /* optional qdisc for classful handling (NULL at netem init) */
81 struct Qdisc *qdisc;
82
83 struct qdisc_watchdog watchdog;
84
85 s64 latency;
86 s64 jitter;
87
88 u32 loss;
89 u32 ecn;
90 u32 limit;
91 u32 counter;
92 u32 gap;
93 u32 duplicate;
94 u32 reorder;
95 u32 corrupt;
96 u64 rate;
97 s32 packet_overhead;
98 u32 cell_size;
99 struct reciprocal_value cell_size_reciprocal;
100 s32 cell_overhead;
101
102 struct crndstate {
103 u32 last;
104 u32 rho;
105 } delay_cor, loss_cor, dup_cor, reorder_cor, corrupt_cor;
106
107 struct disttable *delay_dist;
108
109 enum {
110 CLG_RANDOM,
111 CLG_4_STATES,
112 CLG_GILB_ELL,
113 } loss_model;
114
115 enum {
116 TX_IN_GAP_PERIOD = 1,
117 TX_IN_BURST_PERIOD,
118 LOST_IN_GAP_PERIOD,
119 LOST_IN_BURST_PERIOD,
120 } _4_state_model;
121
122 enum {
123 GOOD_STATE = 1,
124 BAD_STATE,
125 } GE_state_model;
126
127 /* Correlated Loss Generation models */
128 struct clgstate {
129 /* state of the Markov chain */
130 u8 state;
131
132 /* 4-states and Gilbert-Elliot models */
133 u32 a1; /* p13 for 4-states or p for GE */
134 u32 a2; /* p31 for 4-states or r for GE */
135 u32 a3; /* p32 for 4-states or h for GE */
136 u32 a4; /* p14 for 4-states or 1-k for GE */
137 u32 a5; /* p23 used only in 4-states */
138 } clg;
139
140 struct tc_netem_slot slot_config;
141 struct slotstate {
142 u64 slot_next;
143 s32 packets_left;
144 s32 bytes_left;
145 } slot;
146
147 struct disttable *slot_dist;
148};
149
150/* Time stamp put into socket buffer control block
151 * Only valid when skbs are in our internal t(ime)fifo queue.
152 *
153 * As skb->rbnode uses same storage than skb->next, skb->prev and skb->tstamp,
154 * and skb->next & skb->prev are scratch space for a qdisc,
155 * we save skb->tstamp value in skb->cb[] before destroying it.
156 */
157struct netem_skb_cb {
158 u64 time_to_send;
159};
160
161static inline struct netem_skb_cb *netem_skb_cb(struct sk_buff *skb)
162{
163 /* we assume we can use skb next/prev/tstamp as storage for rb_node */
164 qdisc_cb_private_validate(skb, sizeof(struct netem_skb_cb));
165 return (struct netem_skb_cb *)qdisc_skb_cb(skb)->data;
166}
167
168/* init_crandom - initialize correlated random number generator
169 * Use entropy source for initial seed.
170 */
171static void init_crandom(struct crndstate *state, unsigned long rho)
172{
173 state->rho = rho;
174 state->last = get_random_u32();
175}
176
177/* get_crandom - correlated random number generator
178 * Next number depends on last value.
179 * rho is scaled to avoid floating point.
180 */
181static u32 get_crandom(struct crndstate *state)
182{
183 u64 value, rho;
184 unsigned long answer;
185
186 if (!state || state->rho == 0) /* no correlation */
187 return get_random_u32();
188
189 value = get_random_u32();
190 rho = (u64)state->rho + 1;
191 answer = (value * ((1ull<<32) - rho) + state->last * rho) >> 32;
192 state->last = answer;
193 return answer;
194}
195
196/* loss_4state - 4-state model loss generator
197 * Generates losses according to the 4-state Markov chain adopted in
198 * the GI (General and Intuitive) loss model.
199 */
200static bool loss_4state(struct netem_sched_data *q)
201{
202 struct clgstate *clg = &q->clg;
203 u32 rnd = get_random_u32();
204
205 /*
206 * Makes a comparison between rnd and the transition
207 * probabilities outgoing from the current state, then decides the
208 * next state and if the next packet has to be transmitted or lost.
209 * The four states correspond to:
210 * TX_IN_GAP_PERIOD => successfully transmitted packets within a gap period
211 * LOST_IN_GAP_PERIOD => isolated losses within a gap period
212 * LOST_IN_BURST_PERIOD => lost packets within a burst period
213 * TX_IN_BURST_PERIOD => successfully transmitted packets within a burst period
214 */
215 switch (clg->state) {
216 case TX_IN_GAP_PERIOD:
217 if (rnd < clg->a4) {
218 clg->state = LOST_IN_GAP_PERIOD;
219 return true;
220 } else if (clg->a4 < rnd && rnd < clg->a1 + clg->a4) {
221 clg->state = LOST_IN_BURST_PERIOD;
222 return true;
223 } else if (clg->a1 + clg->a4 < rnd) {
224 clg->state = TX_IN_GAP_PERIOD;
225 }
226
227 break;
228 case TX_IN_BURST_PERIOD:
229 if (rnd < clg->a5) {
230 clg->state = LOST_IN_BURST_PERIOD;
231 return true;
232 } else {
233 clg->state = TX_IN_BURST_PERIOD;
234 }
235
236 break;
237 case LOST_IN_BURST_PERIOD:
238 if (rnd < clg->a3)
239 clg->state = TX_IN_BURST_PERIOD;
240 else if (clg->a3 < rnd && rnd < clg->a2 + clg->a3) {
241 clg->state = TX_IN_GAP_PERIOD;
242 } else if (clg->a2 + clg->a3 < rnd) {
243 clg->state = LOST_IN_BURST_PERIOD;
244 return true;
245 }
246 break;
247 case LOST_IN_GAP_PERIOD:
248 clg->state = TX_IN_GAP_PERIOD;
249 break;
250 }
251
252 return false;
253}
254
255/* loss_gilb_ell - Gilbert-Elliot model loss generator
256 * Generates losses according to the Gilbert-Elliot loss model or
257 * its special cases (Gilbert or Simple Gilbert)
258 *
259 * Makes a comparison between random number and the transition
260 * probabilities outgoing from the current state, then decides the
261 * next state. A second random number is extracted and the comparison
262 * with the loss probability of the current state decides if the next
263 * packet will be transmitted or lost.
264 */
265static bool loss_gilb_ell(struct netem_sched_data *q)
266{
267 struct clgstate *clg = &q->clg;
268
269 switch (clg->state) {
270 case GOOD_STATE:
271 if (get_random_u32() < clg->a1)
272 clg->state = BAD_STATE;
273 if (get_random_u32() < clg->a4)
274 return true;
275 break;
276 case BAD_STATE:
277 if (get_random_u32() < clg->a2)
278 clg->state = GOOD_STATE;
279 if (get_random_u32() > clg->a3)
280 return true;
281 }
282
283 return false;
284}
285
286static bool loss_event(struct netem_sched_data *q)
287{
288 switch (q->loss_model) {
289 case CLG_RANDOM:
290 /* Random packet drop 0 => none, ~0 => all */
291 return q->loss && q->loss >= get_crandom(&q->loss_cor);
292
293 case CLG_4_STATES:
294 /* 4state loss model algorithm (used also for GI model)
295 * Extracts a value from the markov 4 state loss generator,
296 * if it is 1 drops a packet and if needed writes the event in
297 * the kernel logs
298 */
299 return loss_4state(q);
300
301 case CLG_GILB_ELL:
302 /* Gilbert-Elliot loss model algorithm
303 * Extracts a value from the Gilbert-Elliot loss generator,
304 * if it is 1 drops a packet and if needed writes the event in
305 * the kernel logs
306 */
307 return loss_gilb_ell(q);
308 }
309
310 return false; /* not reached */
311}
312
313
314/* tabledist - return a pseudo-randomly distributed value with mean mu and
315 * std deviation sigma. Uses table lookup to approximate the desired
316 * distribution, and a uniformly-distributed pseudo-random source.
317 */
318static s64 tabledist(s64 mu, s32 sigma,
319 struct crndstate *state,
320 const struct disttable *dist)
321{
322 s64 x;
323 long t;
324 u32 rnd;
325
326 if (sigma == 0)
327 return mu;
328
329 rnd = get_crandom(state);
330
331 /* default uniform distribution */
332 if (dist == NULL)
333 return ((rnd % (2 * (u32)sigma)) + mu) - sigma;
334
335 t = dist->table[rnd % dist->size];
336 x = (sigma % NETEM_DIST_SCALE) * t;
337 if (x >= 0)
338 x += NETEM_DIST_SCALE/2;
339 else
340 x -= NETEM_DIST_SCALE/2;
341
342 return x / NETEM_DIST_SCALE + (sigma / NETEM_DIST_SCALE) * t + mu;
343}
344
345static u64 packet_time_ns(u64 len, const struct netem_sched_data *q)
346{
347 len += q->packet_overhead;
348
349 if (q->cell_size) {
350 u32 cells = reciprocal_divide(len, q->cell_size_reciprocal);
351
352 if (len > cells * q->cell_size) /* extra cell needed for remainder */
353 cells++;
354 len = cells * (q->cell_size + q->cell_overhead);
355 }
356
357 return div64_u64(len * NSEC_PER_SEC, q->rate);
358}
359
360static void tfifo_reset(struct Qdisc *sch)
361{
362 struct netem_sched_data *q = qdisc_priv(sch);
363 struct rb_node *p = rb_first(&q->t_root);
364
365 while (p) {
366 struct sk_buff *skb = rb_to_skb(p);
367
368 p = rb_next(p);
369 rb_erase(&skb->rbnode, &q->t_root);
370 rtnl_kfree_skbs(skb, skb);
371 }
372
373 rtnl_kfree_skbs(q->t_head, q->t_tail);
374 q->t_head = NULL;
375 q->t_tail = NULL;
376}
377
378static void tfifo_enqueue(struct sk_buff *nskb, struct Qdisc *sch)
379{
380 struct netem_sched_data *q = qdisc_priv(sch);
381 u64 tnext = netem_skb_cb(nskb)->time_to_send;
382
383 if (!q->t_tail || tnext >= netem_skb_cb(q->t_tail)->time_to_send) {
384 if (q->t_tail)
385 q->t_tail->next = nskb;
386 else
387 q->t_head = nskb;
388 q->t_tail = nskb;
389 } else {
390 struct rb_node **p = &q->t_root.rb_node, *parent = NULL;
391
392 while (*p) {
393 struct sk_buff *skb;
394
395 parent = *p;
396 skb = rb_to_skb(parent);
397 if (tnext >= netem_skb_cb(skb)->time_to_send)
398 p = &parent->rb_right;
399 else
400 p = &parent->rb_left;
401 }
402 rb_link_node(&nskb->rbnode, parent, p);
403 rb_insert_color(&nskb->rbnode, &q->t_root);
404 }
405 sch->q.qlen++;
406}
407
408/* netem can't properly corrupt a megapacket (like we get from GSO), so instead
409 * when we statistically choose to corrupt one, we instead segment it, returning
410 * the first packet to be corrupted, and re-enqueue the remaining frames
411 */
412static struct sk_buff *netem_segment(struct sk_buff *skb, struct Qdisc *sch,
413 struct sk_buff **to_free)
414{
415 struct sk_buff *segs;
416 netdev_features_t features = netif_skb_features(skb);
417
418 segs = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK);
419
420 if (IS_ERR_OR_NULL(segs)) {
421 qdisc_drop(skb, sch, to_free);
422 return NULL;
423 }
424 consume_skb(skb);
425 return segs;
426}
427
428/*
429 * Insert one skb into qdisc.
430 * Note: parent depends on return value to account for queue length.
431 * NET_XMIT_DROP: queue length didn't change.
432 * NET_XMIT_SUCCESS: one skb was queued.
433 */
434static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
435 struct sk_buff **to_free)
436{
437 struct netem_sched_data *q = qdisc_priv(sch);
438 /* We don't fill cb now as skb_unshare() may invalidate it */
439 struct netem_skb_cb *cb;
440 struct sk_buff *skb2;
441 struct sk_buff *segs = NULL;
442 unsigned int prev_len = qdisc_pkt_len(skb);
443 int count = 1;
444 int rc = NET_XMIT_SUCCESS;
445 int rc_drop = NET_XMIT_DROP;
446
447 /* Do not fool qdisc_drop_all() */
448 skb->prev = NULL;
449
450 /* Random duplication */
451 if (q->duplicate && q->duplicate >= get_crandom(&q->dup_cor))
452 ++count;
453
454 /* Drop packet? */
455 if (loss_event(q)) {
456 if (q->ecn && INET_ECN_set_ce(skb))
457 qdisc_qstats_drop(sch); /* mark packet */
458 else
459 --count;
460 }
461 if (count == 0) {
462 qdisc_qstats_drop(sch);
463 __qdisc_drop(skb, to_free);
464 return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
465 }
466
467 /* If a delay is expected, orphan the skb. (orphaning usually takes
468 * place at TX completion time, so _before_ the link transit delay)
469 */
470 if (q->latency || q->jitter || q->rate)
471 skb_orphan_partial(skb);
472
473 /*
474 * If we need to duplicate packet, then re-insert at top of the
475 * qdisc tree, since parent queuer expects that only one
476 * skb will be queued.
477 */
478 if (count > 1 && (skb2 = skb_clone(skb, GFP_ATOMIC)) != NULL) {
479 struct Qdisc *rootq = qdisc_root_bh(sch);
480 u32 dupsave = q->duplicate; /* prevent duplicating a dup... */
481
482 q->duplicate = 0;
483 rootq->enqueue(skb2, rootq, to_free);
484 q->duplicate = dupsave;
485 rc_drop = NET_XMIT_SUCCESS;
486 }
487
488 /*
489 * Randomized packet corruption.
490 * Make copy if needed since we are modifying
491 * If packet is going to be hardware checksummed, then
492 * do it now in software before we mangle it.
493 */
494 if (q->corrupt && q->corrupt >= get_crandom(&q->corrupt_cor)) {
495 if (skb_is_gso(skb)) {
496 skb = netem_segment(skb, sch, to_free);
497 if (!skb)
498 return rc_drop;
499 segs = skb->next;
500 skb_mark_not_on_list(skb);
501 qdisc_skb_cb(skb)->pkt_len = skb->len;
502 }
503
504 skb = skb_unshare(skb, GFP_ATOMIC);
505 if (unlikely(!skb)) {
506 qdisc_qstats_drop(sch);
507 goto finish_segs;
508 }
509 if (skb->ip_summed == CHECKSUM_PARTIAL &&
510 skb_checksum_help(skb)) {
511 qdisc_drop(skb, sch, to_free);
512 skb = NULL;
513 goto finish_segs;
514 }
515
516 skb->data[get_random_u32_below(skb_headlen(skb))] ^=
517 1<<get_random_u32_below(8);
518 }
519
520 if (unlikely(sch->q.qlen >= sch->limit)) {
521 /* re-link segs, so that qdisc_drop_all() frees them all */
522 skb->next = segs;
523 qdisc_drop_all(skb, sch, to_free);
524 return rc_drop;
525 }
526
527 qdisc_qstats_backlog_inc(sch, skb);
528
529 cb = netem_skb_cb(skb);
530 if (q->gap == 0 || /* not doing reordering */
531 q->counter < q->gap - 1 || /* inside last reordering gap */
532 q->reorder < get_crandom(&q->reorder_cor)) {
533 u64 now;
534 s64 delay;
535
536 delay = tabledist(q->latency, q->jitter,
537 &q->delay_cor, q->delay_dist);
538
539 now = ktime_get_ns();
540
541 if (q->rate) {
542 struct netem_skb_cb *last = NULL;
543
544 if (sch->q.tail)
545 last = netem_skb_cb(sch->q.tail);
546 if (q->t_root.rb_node) {
547 struct sk_buff *t_skb;
548 struct netem_skb_cb *t_last;
549
550 t_skb = skb_rb_last(&q->t_root);
551 t_last = netem_skb_cb(t_skb);
552 if (!last ||
553 t_last->time_to_send > last->time_to_send)
554 last = t_last;
555 }
556 if (q->t_tail) {
557 struct netem_skb_cb *t_last =
558 netem_skb_cb(q->t_tail);
559
560 if (!last ||
561 t_last->time_to_send > last->time_to_send)
562 last = t_last;
563 }
564
565 if (last) {
566 /*
567 * Last packet in queue is reference point (now),
568 * calculate this time bonus and subtract
569 * from delay.
570 */
571 delay -= last->time_to_send - now;
572 delay = max_t(s64, 0, delay);
573 now = last->time_to_send;
574 }
575
576 delay += packet_time_ns(qdisc_pkt_len(skb), q);
577 }
578
579 cb->time_to_send = now + delay;
580 ++q->counter;
581 tfifo_enqueue(skb, sch);
582 } else {
583 /*
584 * Do re-ordering by putting one out of N packets at the front
585 * of the queue.
586 */
587 cb->time_to_send = ktime_get_ns();
588 q->counter = 0;
589
590 __qdisc_enqueue_head(skb, &sch->q);
591 sch->qstats.requeues++;
592 }
593
594finish_segs:
595 if (segs) {
596 unsigned int len, last_len;
597 int nb;
598
599 len = skb ? skb->len : 0;
600 nb = skb ? 1 : 0;
601
602 while (segs) {
603 skb2 = segs->next;
604 skb_mark_not_on_list(segs);
605 qdisc_skb_cb(segs)->pkt_len = segs->len;
606 last_len = segs->len;
607 rc = qdisc_enqueue(segs, sch, to_free);
608 if (rc != NET_XMIT_SUCCESS) {
609 if (net_xmit_drop_count(rc))
610 qdisc_qstats_drop(sch);
611 } else {
612 nb++;
613 len += last_len;
614 }
615 segs = skb2;
616 }
617 /* Parent qdiscs accounted for 1 skb of size @prev_len */
618 qdisc_tree_reduce_backlog(sch, -(nb - 1), -(len - prev_len));
619 } else if (!skb) {
620 return NET_XMIT_DROP;
621 }
622 return NET_XMIT_SUCCESS;
623}
624
625/* Delay the next round with a new future slot with a
626 * correct number of bytes and packets.
627 */
628
629static void get_slot_next(struct netem_sched_data *q, u64 now)
630{
631 s64 next_delay;
632
633 if (!q->slot_dist)
634 next_delay = q->slot_config.min_delay +
635 (get_random_u32() *
636 (q->slot_config.max_delay -
637 q->slot_config.min_delay) >> 32);
638 else
639 next_delay = tabledist(q->slot_config.dist_delay,
640 (s32)(q->slot_config.dist_jitter),
641 NULL, q->slot_dist);
642
643 q->slot.slot_next = now + next_delay;
644 q->slot.packets_left = q->slot_config.max_packets;
645 q->slot.bytes_left = q->slot_config.max_bytes;
646}
647
648static struct sk_buff *netem_peek(struct netem_sched_data *q)
649{
650 struct sk_buff *skb = skb_rb_first(&q->t_root);
651 u64 t1, t2;
652
653 if (!skb)
654 return q->t_head;
655 if (!q->t_head)
656 return skb;
657
658 t1 = netem_skb_cb(skb)->time_to_send;
659 t2 = netem_skb_cb(q->t_head)->time_to_send;
660 if (t1 < t2)
661 return skb;
662 return q->t_head;
663}
664
665static void netem_erase_head(struct netem_sched_data *q, struct sk_buff *skb)
666{
667 if (skb == q->t_head) {
668 q->t_head = skb->next;
669 if (!q->t_head)
670 q->t_tail = NULL;
671 } else {
672 rb_erase(&skb->rbnode, &q->t_root);
673 }
674}
675
676static struct sk_buff *netem_dequeue(struct Qdisc *sch)
677{
678 struct netem_sched_data *q = qdisc_priv(sch);
679 struct sk_buff *skb;
680
681tfifo_dequeue:
682 skb = __qdisc_dequeue_head(&sch->q);
683 if (skb) {
684 qdisc_qstats_backlog_dec(sch, skb);
685deliver:
686 qdisc_bstats_update(sch, skb);
687 return skb;
688 }
689 skb = netem_peek(q);
690 if (skb) {
691 u64 time_to_send;
692 u64 now = ktime_get_ns();
693
694 /* if more time remaining? */
695 time_to_send = netem_skb_cb(skb)->time_to_send;
696 if (q->slot.slot_next && q->slot.slot_next < time_to_send)
697 get_slot_next(q, now);
698
699 if (time_to_send <= now && q->slot.slot_next <= now) {
700 netem_erase_head(q, skb);
701 sch->q.qlen--;
702 qdisc_qstats_backlog_dec(sch, skb);
703 skb->next = NULL;
704 skb->prev = NULL;
705 /* skb->dev shares skb->rbnode area,
706 * we need to restore its value.
707 */
708 skb->dev = qdisc_dev(sch);
709
710 if (q->slot.slot_next) {
711 q->slot.packets_left--;
712 q->slot.bytes_left -= qdisc_pkt_len(skb);
713 if (q->slot.packets_left <= 0 ||
714 q->slot.bytes_left <= 0)
715 get_slot_next(q, now);
716 }
717
718 if (q->qdisc) {
719 unsigned int pkt_len = qdisc_pkt_len(skb);
720 struct sk_buff *to_free = NULL;
721 int err;
722
723 err = qdisc_enqueue(skb, q->qdisc, &to_free);
724 kfree_skb_list(to_free);
725 if (err != NET_XMIT_SUCCESS &&
726 net_xmit_drop_count(err)) {
727 qdisc_qstats_drop(sch);
728 qdisc_tree_reduce_backlog(sch, 1,
729 pkt_len);
730 }
731 goto tfifo_dequeue;
732 }
733 goto deliver;
734 }
735
736 if (q->qdisc) {
737 skb = q->qdisc->ops->dequeue(q->qdisc);
738 if (skb)
739 goto deliver;
740 }
741
742 qdisc_watchdog_schedule_ns(&q->watchdog,
743 max(time_to_send,
744 q->slot.slot_next));
745 }
746
747 if (q->qdisc) {
748 skb = q->qdisc->ops->dequeue(q->qdisc);
749 if (skb)
750 goto deliver;
751 }
752 return NULL;
753}
754
755static void netem_reset(struct Qdisc *sch)
756{
757 struct netem_sched_data *q = qdisc_priv(sch);
758
759 qdisc_reset_queue(sch);
760 tfifo_reset(sch);
761 if (q->qdisc)
762 qdisc_reset(q->qdisc);
763 qdisc_watchdog_cancel(&q->watchdog);
764}
765
766static void dist_free(struct disttable *d)
767{
768 kvfree(d);
769}
770
771/*
772 * Distribution data is a variable size payload containing
773 * signed 16 bit values.
774 */
775
776static int get_dist_table(struct Qdisc *sch, struct disttable **tbl,
777 const struct nlattr *attr)
778{
779 size_t n = nla_len(attr)/sizeof(__s16);
780 const __s16 *data = nla_data(attr);
781 spinlock_t *root_lock;
782 struct disttable *d;
783 int i;
784
785 if (!n || n > NETEM_DIST_MAX)
786 return -EINVAL;
787
788 d = kvmalloc(struct_size(d, table, n), GFP_KERNEL);
789 if (!d)
790 return -ENOMEM;
791
792 d->size = n;
793 for (i = 0; i < n; i++)
794 d->table[i] = data[i];
795
796 root_lock = qdisc_root_sleeping_lock(sch);
797
798 spin_lock_bh(root_lock);
799 swap(*tbl, d);
800 spin_unlock_bh(root_lock);
801
802 dist_free(d);
803 return 0;
804}
805
806static void get_slot(struct netem_sched_data *q, const struct nlattr *attr)
807{
808 const struct tc_netem_slot *c = nla_data(attr);
809
810 q->slot_config = *c;
811 if (q->slot_config.max_packets == 0)
812 q->slot_config.max_packets = INT_MAX;
813 if (q->slot_config.max_bytes == 0)
814 q->slot_config.max_bytes = INT_MAX;
815
816 /* capping dist_jitter to the range acceptable by tabledist() */
817 q->slot_config.dist_jitter = min_t(__s64, INT_MAX, abs(q->slot_config.dist_jitter));
818
819 q->slot.packets_left = q->slot_config.max_packets;
820 q->slot.bytes_left = q->slot_config.max_bytes;
821 if (q->slot_config.min_delay | q->slot_config.max_delay |
822 q->slot_config.dist_jitter)
823 q->slot.slot_next = ktime_get_ns();
824 else
825 q->slot.slot_next = 0;
826}
827
828static void get_correlation(struct netem_sched_data *q, const struct nlattr *attr)
829{
830 const struct tc_netem_corr *c = nla_data(attr);
831
832 init_crandom(&q->delay_cor, c->delay_corr);
833 init_crandom(&q->loss_cor, c->loss_corr);
834 init_crandom(&q->dup_cor, c->dup_corr);
835}
836
837static void get_reorder(struct netem_sched_data *q, const struct nlattr *attr)
838{
839 const struct tc_netem_reorder *r = nla_data(attr);
840
841 q->reorder = r->probability;
842 init_crandom(&q->reorder_cor, r->correlation);
843}
844
845static void get_corrupt(struct netem_sched_data *q, const struct nlattr *attr)
846{
847 const struct tc_netem_corrupt *r = nla_data(attr);
848
849 q->corrupt = r->probability;
850 init_crandom(&q->corrupt_cor, r->correlation);
851}
852
853static void get_rate(struct netem_sched_data *q, const struct nlattr *attr)
854{
855 const struct tc_netem_rate *r = nla_data(attr);
856
857 q->rate = r->rate;
858 q->packet_overhead = r->packet_overhead;
859 q->cell_size = r->cell_size;
860 q->cell_overhead = r->cell_overhead;
861 if (q->cell_size)
862 q->cell_size_reciprocal = reciprocal_value(q->cell_size);
863 else
864 q->cell_size_reciprocal = (struct reciprocal_value) { 0 };
865}
866
867static int get_loss_clg(struct netem_sched_data *q, const struct nlattr *attr)
868{
869 const struct nlattr *la;
870 int rem;
871
872 nla_for_each_nested(la, attr, rem) {
873 u16 type = nla_type(la);
874
875 switch (type) {
876 case NETEM_LOSS_GI: {
877 const struct tc_netem_gimodel *gi = nla_data(la);
878
879 if (nla_len(la) < sizeof(struct tc_netem_gimodel)) {
880 pr_info("netem: incorrect gi model size\n");
881 return -EINVAL;
882 }
883
884 q->loss_model = CLG_4_STATES;
885
886 q->clg.state = TX_IN_GAP_PERIOD;
887 q->clg.a1 = gi->p13;
888 q->clg.a2 = gi->p31;
889 q->clg.a3 = gi->p32;
890 q->clg.a4 = gi->p14;
891 q->clg.a5 = gi->p23;
892 break;
893 }
894
895 case NETEM_LOSS_GE: {
896 const struct tc_netem_gemodel *ge = nla_data(la);
897
898 if (nla_len(la) < sizeof(struct tc_netem_gemodel)) {
899 pr_info("netem: incorrect ge model size\n");
900 return -EINVAL;
901 }
902
903 q->loss_model = CLG_GILB_ELL;
904 q->clg.state = GOOD_STATE;
905 q->clg.a1 = ge->p;
906 q->clg.a2 = ge->r;
907 q->clg.a3 = ge->h;
908 q->clg.a4 = ge->k1;
909 break;
910 }
911
912 default:
913 pr_info("netem: unknown loss type %u\n", type);
914 return -EINVAL;
915 }
916 }
917
918 return 0;
919}
920
921static const struct nla_policy netem_policy[TCA_NETEM_MAX + 1] = {
922 [TCA_NETEM_CORR] = { .len = sizeof(struct tc_netem_corr) },
923 [TCA_NETEM_REORDER] = { .len = sizeof(struct tc_netem_reorder) },
924 [TCA_NETEM_CORRUPT] = { .len = sizeof(struct tc_netem_corrupt) },
925 [TCA_NETEM_RATE] = { .len = sizeof(struct tc_netem_rate) },
926 [TCA_NETEM_LOSS] = { .type = NLA_NESTED },
927 [TCA_NETEM_ECN] = { .type = NLA_U32 },
928 [TCA_NETEM_RATE64] = { .type = NLA_U64 },
929 [TCA_NETEM_LATENCY64] = { .type = NLA_S64 },
930 [TCA_NETEM_JITTER64] = { .type = NLA_S64 },
931 [TCA_NETEM_SLOT] = { .len = sizeof(struct tc_netem_slot) },
932};
933
934static int parse_attr(struct nlattr *tb[], int maxtype, struct nlattr *nla,
935 const struct nla_policy *policy, int len)
936{
937 int nested_len = nla_len(nla) - NLA_ALIGN(len);
938
939 if (nested_len < 0) {
940 pr_info("netem: invalid attributes len %d\n", nested_len);
941 return -EINVAL;
942 }
943
944 if (nested_len >= nla_attr_size(0))
945 return nla_parse_deprecated(tb, maxtype,
946 nla_data(nla) + NLA_ALIGN(len),
947 nested_len, policy, NULL);
948
949 memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
950 return 0;
951}
952
953/* Parse netlink message to set options */
954static int netem_change(struct Qdisc *sch, struct nlattr *opt,
955 struct netlink_ext_ack *extack)
956{
957 struct netem_sched_data *q = qdisc_priv(sch);
958 struct nlattr *tb[TCA_NETEM_MAX + 1];
959 struct tc_netem_qopt *qopt;
960 struct clgstate old_clg;
961 int old_loss_model = CLG_RANDOM;
962 int ret;
963
964 qopt = nla_data(opt);
965 ret = parse_attr(tb, TCA_NETEM_MAX, opt, netem_policy, sizeof(*qopt));
966 if (ret < 0)
967 return ret;
968
969 /* backup q->clg and q->loss_model */
970 old_clg = q->clg;
971 old_loss_model = q->loss_model;
972
973 if (tb[TCA_NETEM_LOSS]) {
974 ret = get_loss_clg(q, tb[TCA_NETEM_LOSS]);
975 if (ret) {
976 q->loss_model = old_loss_model;
977 return ret;
978 }
979 } else {
980 q->loss_model = CLG_RANDOM;
981 }
982
983 if (tb[TCA_NETEM_DELAY_DIST]) {
984 ret = get_dist_table(sch, &q->delay_dist,
985 tb[TCA_NETEM_DELAY_DIST]);
986 if (ret)
987 goto get_table_failure;
988 }
989
990 if (tb[TCA_NETEM_SLOT_DIST]) {
991 ret = get_dist_table(sch, &q->slot_dist,
992 tb[TCA_NETEM_SLOT_DIST]);
993 if (ret)
994 goto get_table_failure;
995 }
996
997 sch->limit = qopt->limit;
998
999 q->latency = PSCHED_TICKS2NS(qopt->latency);
1000 q->jitter = PSCHED_TICKS2NS(qopt->jitter);
1001 q->limit = qopt->limit;
1002 q->gap = qopt->gap;
1003 q->counter = 0;
1004 q->loss = qopt->loss;
1005 q->duplicate = qopt->duplicate;
1006
1007 /* for compatibility with earlier versions.
1008 * if gap is set, need to assume 100% probability
1009 */
1010 if (q->gap)
1011 q->reorder = ~0;
1012
1013 if (tb[TCA_NETEM_CORR])
1014 get_correlation(q, tb[TCA_NETEM_CORR]);
1015
1016 if (tb[TCA_NETEM_REORDER])
1017 get_reorder(q, tb[TCA_NETEM_REORDER]);
1018
1019 if (tb[TCA_NETEM_CORRUPT])
1020 get_corrupt(q, tb[TCA_NETEM_CORRUPT]);
1021
1022 if (tb[TCA_NETEM_RATE])
1023 get_rate(q, tb[TCA_NETEM_RATE]);
1024
1025 if (tb[TCA_NETEM_RATE64])
1026 q->rate = max_t(u64, q->rate,
1027 nla_get_u64(tb[TCA_NETEM_RATE64]));
1028
1029 if (tb[TCA_NETEM_LATENCY64])
1030 q->latency = nla_get_s64(tb[TCA_NETEM_LATENCY64]);
1031
1032 if (tb[TCA_NETEM_JITTER64])
1033 q->jitter = nla_get_s64(tb[TCA_NETEM_JITTER64]);
1034
1035 if (tb[TCA_NETEM_ECN])
1036 q->ecn = nla_get_u32(tb[TCA_NETEM_ECN]);
1037
1038 if (tb[TCA_NETEM_SLOT])
1039 get_slot(q, tb[TCA_NETEM_SLOT]);
1040
1041 /* capping jitter to the range acceptable by tabledist() */
1042 q->jitter = min_t(s64, abs(q->jitter), INT_MAX);
1043
1044 return ret;
1045
1046get_table_failure:
1047 /* recover clg and loss_model, in case of
1048 * q->clg and q->loss_model were modified
1049 * in get_loss_clg()
1050 */
1051 q->clg = old_clg;
1052 q->loss_model = old_loss_model;
1053 return ret;
1054}
1055
1056static int netem_init(struct Qdisc *sch, struct nlattr *opt,
1057 struct netlink_ext_ack *extack)
1058{
1059 struct netem_sched_data *q = qdisc_priv(sch);
1060 int ret;
1061
1062 qdisc_watchdog_init(&q->watchdog, sch);
1063
1064 if (!opt)
1065 return -EINVAL;
1066
1067 q->loss_model = CLG_RANDOM;
1068 ret = netem_change(sch, opt, extack);
1069 if (ret)
1070 pr_info("netem: change failed\n");
1071 return ret;
1072}
1073
1074static void netem_destroy(struct Qdisc *sch)
1075{
1076 struct netem_sched_data *q = qdisc_priv(sch);
1077
1078 qdisc_watchdog_cancel(&q->watchdog);
1079 if (q->qdisc)
1080 qdisc_put(q->qdisc);
1081 dist_free(q->delay_dist);
1082 dist_free(q->slot_dist);
1083}
1084
1085static int dump_loss_model(const struct netem_sched_data *q,
1086 struct sk_buff *skb)
1087{
1088 struct nlattr *nest;
1089
1090 nest = nla_nest_start_noflag(skb, TCA_NETEM_LOSS);
1091 if (nest == NULL)
1092 goto nla_put_failure;
1093
1094 switch (q->loss_model) {
1095 case CLG_RANDOM:
1096 /* legacy loss model */
1097 nla_nest_cancel(skb, nest);
1098 return 0; /* no data */
1099
1100 case CLG_4_STATES: {
1101 struct tc_netem_gimodel gi = {
1102 .p13 = q->clg.a1,
1103 .p31 = q->clg.a2,
1104 .p32 = q->clg.a3,
1105 .p14 = q->clg.a4,
1106 .p23 = q->clg.a5,
1107 };
1108
1109 if (nla_put(skb, NETEM_LOSS_GI, sizeof(gi), &gi))
1110 goto nla_put_failure;
1111 break;
1112 }
1113 case CLG_GILB_ELL: {
1114 struct tc_netem_gemodel ge = {
1115 .p = q->clg.a1,
1116 .r = q->clg.a2,
1117 .h = q->clg.a3,
1118 .k1 = q->clg.a4,
1119 };
1120
1121 if (nla_put(skb, NETEM_LOSS_GE, sizeof(ge), &ge))
1122 goto nla_put_failure;
1123 break;
1124 }
1125 }
1126
1127 nla_nest_end(skb, nest);
1128 return 0;
1129
1130nla_put_failure:
1131 nla_nest_cancel(skb, nest);
1132 return -1;
1133}
1134
1135static int netem_dump(struct Qdisc *sch, struct sk_buff *skb)
1136{
1137 const struct netem_sched_data *q = qdisc_priv(sch);
1138 struct nlattr *nla = (struct nlattr *) skb_tail_pointer(skb);
1139 struct tc_netem_qopt qopt;
1140 struct tc_netem_corr cor;
1141 struct tc_netem_reorder reorder;
1142 struct tc_netem_corrupt corrupt;
1143 struct tc_netem_rate rate;
1144 struct tc_netem_slot slot;
1145
1146 qopt.latency = min_t(psched_time_t, PSCHED_NS2TICKS(q->latency),
1147 UINT_MAX);
1148 qopt.jitter = min_t(psched_time_t, PSCHED_NS2TICKS(q->jitter),
1149 UINT_MAX);
1150 qopt.limit = q->limit;
1151 qopt.loss = q->loss;
1152 qopt.gap = q->gap;
1153 qopt.duplicate = q->duplicate;
1154 if (nla_put(skb, TCA_OPTIONS, sizeof(qopt), &qopt))
1155 goto nla_put_failure;
1156
1157 if (nla_put(skb, TCA_NETEM_LATENCY64, sizeof(q->latency), &q->latency))
1158 goto nla_put_failure;
1159
1160 if (nla_put(skb, TCA_NETEM_JITTER64, sizeof(q->jitter), &q->jitter))
1161 goto nla_put_failure;
1162
1163 cor.delay_corr = q->delay_cor.rho;
1164 cor.loss_corr = q->loss_cor.rho;
1165 cor.dup_corr = q->dup_cor.rho;
1166 if (nla_put(skb, TCA_NETEM_CORR, sizeof(cor), &cor))
1167 goto nla_put_failure;
1168
1169 reorder.probability = q->reorder;
1170 reorder.correlation = q->reorder_cor.rho;
1171 if (nla_put(skb, TCA_NETEM_REORDER, sizeof(reorder), &reorder))
1172 goto nla_put_failure;
1173
1174 corrupt.probability = q->corrupt;
1175 corrupt.correlation = q->corrupt_cor.rho;
1176 if (nla_put(skb, TCA_NETEM_CORRUPT, sizeof(corrupt), &corrupt))
1177 goto nla_put_failure;
1178
1179 if (q->rate >= (1ULL << 32)) {
1180 if (nla_put_u64_64bit(skb, TCA_NETEM_RATE64, q->rate,
1181 TCA_NETEM_PAD))
1182 goto nla_put_failure;
1183 rate.rate = ~0U;
1184 } else {
1185 rate.rate = q->rate;
1186 }
1187 rate.packet_overhead = q->packet_overhead;
1188 rate.cell_size = q->cell_size;
1189 rate.cell_overhead = q->cell_overhead;
1190 if (nla_put(skb, TCA_NETEM_RATE, sizeof(rate), &rate))
1191 goto nla_put_failure;
1192
1193 if (q->ecn && nla_put_u32(skb, TCA_NETEM_ECN, q->ecn))
1194 goto nla_put_failure;
1195
1196 if (dump_loss_model(q, skb) != 0)
1197 goto nla_put_failure;
1198
1199 if (q->slot_config.min_delay | q->slot_config.max_delay |
1200 q->slot_config.dist_jitter) {
1201 slot = q->slot_config;
1202 if (slot.max_packets == INT_MAX)
1203 slot.max_packets = 0;
1204 if (slot.max_bytes == INT_MAX)
1205 slot.max_bytes = 0;
1206 if (nla_put(skb, TCA_NETEM_SLOT, sizeof(slot), &slot))
1207 goto nla_put_failure;
1208 }
1209
1210 return nla_nest_end(skb, nla);
1211
1212nla_put_failure:
1213 nlmsg_trim(skb, nla);
1214 return -1;
1215}
1216
1217static int netem_dump_class(struct Qdisc *sch, unsigned long cl,
1218 struct sk_buff *skb, struct tcmsg *tcm)
1219{
1220 struct netem_sched_data *q = qdisc_priv(sch);
1221
1222 if (cl != 1 || !q->qdisc) /* only one class */
1223 return -ENOENT;
1224
1225 tcm->tcm_handle |= TC_H_MIN(1);
1226 tcm->tcm_info = q->qdisc->handle;
1227
1228 return 0;
1229}
1230
1231static int netem_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
1232 struct Qdisc **old, struct netlink_ext_ack *extack)
1233{
1234 struct netem_sched_data *q = qdisc_priv(sch);
1235
1236 *old = qdisc_replace(sch, new, &q->qdisc);
1237 return 0;
1238}
1239
1240static struct Qdisc *netem_leaf(struct Qdisc *sch, unsigned long arg)
1241{
1242 struct netem_sched_data *q = qdisc_priv(sch);
1243 return q->qdisc;
1244}
1245
1246static unsigned long netem_find(struct Qdisc *sch, u32 classid)
1247{
1248 return 1;
1249}
1250
1251static void netem_walk(struct Qdisc *sch, struct qdisc_walker *walker)
1252{
1253 if (!walker->stop) {
1254 if (!tc_qdisc_stats_dump(sch, 1, walker))
1255 return;
1256 }
1257}
1258
1259static const struct Qdisc_class_ops netem_class_ops = {
1260 .graft = netem_graft,
1261 .leaf = netem_leaf,
1262 .find = netem_find,
1263 .walk = netem_walk,
1264 .dump = netem_dump_class,
1265};
1266
1267static struct Qdisc_ops netem_qdisc_ops __read_mostly = {
1268 .id = "netem",
1269 .cl_ops = &netem_class_ops,
1270 .priv_size = sizeof(struct netem_sched_data),
1271 .enqueue = netem_enqueue,
1272 .dequeue = netem_dequeue,
1273 .peek = qdisc_peek_dequeued,
1274 .init = netem_init,
1275 .reset = netem_reset,
1276 .destroy = netem_destroy,
1277 .change = netem_change,
1278 .dump = netem_dump,
1279 .owner = THIS_MODULE,
1280};
1281
1282
1283static int __init netem_module_init(void)
1284{
1285 pr_info("netem: version " VERSION "\n");
1286 return register_qdisc(&netem_qdisc_ops);
1287}
1288static void __exit netem_module_exit(void)
1289{
1290 unregister_qdisc(&netem_qdisc_ops);
1291}
1292module_init(netem_module_init)
1293module_exit(netem_module_exit)
1294MODULE_LICENSE("GPL");