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