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drm/tests: hdmi: Fix memory leaks in drm_display_mode_from_cea_vic()
[drm/drm-misc.git] / net / sched / sch_netem.c
blob39382ee1e33108fb0f495c4c858e28e4f06759a0
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/gso.h>
25 #include <net/netlink.h>
26 #include <net/pkt_sched.h>
27 #include <net/inet_ecn.h>
28
29 #define VERSION "1.3"
30
31 /* Network Emulation Queuing algorithm.
32 ====================================
33
34 Sources: [1] Mark Carson, Darrin Santay, "NIST Net - A Linux-based
35 Network Emulation Tool
36 [2] Luigi Rizzo, DummyNet for FreeBSD
37
38 ----------------------------------------------------------------
39
40 This started out as a simple way to delay outgoing packets to
41 test TCP but has grown to include most of the functionality
42 of a full blown network emulator like NISTnet. It can delay
43 packets and add random jitter (and correlation). The random
44 distribution can be loaded from a table as well to provide
45 normal, Pareto, or experimental curves. Packet loss,
46 duplication, and reordering can also be emulated.
47
48 This qdisc does not do classification that can be handled in
49 layering other disciplines. It does not need to do bandwidth
50 control either since that can be handled by using token
51 bucket or other rate control.
52
53 Correlated Loss Generator models
54
55 Added generation of correlated loss according to the
56 "Gilbert-Elliot" model, a 4-state markov model.
57
58 References:
59 [1] NetemCLG Home http://netgroup.uniroma2.it/NetemCLG
60 [2] S. Salsano, F. Ludovici, A. Ordine, "Definition of a general
61 and intuitive loss model for packet networks and its implementation
62 in the Netem module in the Linux kernel", available in [1]
63
64 Authors: Stefano Salsano <stefano.salsano at uniroma2.it
65 Fabio Ludovici <fabio.ludovici at yahoo.it>
66 */
67
68 struct disttable {
69 u32 size;
70 s16 table[] __counted_by(size);
71 };
72
73 struct netem_sched_data {
74 /* internal t(ime)fifo qdisc uses t_root and sch->limit */
75 struct rb_root t_root;
76
77 /* a linear queue; reduces rbtree rebalancing when jitter is low */
78 struct sk_buff *t_head;
79 struct sk_buff *t_tail;
80
81 /* optional qdisc for classful handling (NULL at netem init) */
82 struct Qdisc *qdisc;
83
84 struct qdisc_watchdog watchdog;
85
86 s64 latency;
87 s64 jitter;
88
89 u32 loss;
90 u32 ecn;
91 u32 limit;
92 u32 counter;
93 u32 gap;
94 u32 duplicate;
95 u32 reorder;
96 u32 corrupt;
97 u64 rate;
98 s32 packet_overhead;
99 u32 cell_size;
100 struct reciprocal_value cell_size_reciprocal;
101 s32 cell_overhead;
102
103 struct crndstate {
104 u32 last;
105 u32 rho;
106 } delay_cor, loss_cor, dup_cor, reorder_cor, corrupt_cor;
107
108 struct prng {
109 u64 seed;
110 struct rnd_state prng_state;
111 } prng;
112
113 struct disttable *delay_dist;
114
115 enum {
116 CLG_RANDOM,
117 CLG_4_STATES,
118 CLG_GILB_ELL,
119 } loss_model;
120
121 enum {
122 TX_IN_GAP_PERIOD = 1,
123 TX_IN_BURST_PERIOD,
124 LOST_IN_GAP_PERIOD,
125 LOST_IN_BURST_PERIOD,
126 } _4_state_model;
127
128 enum {
129 GOOD_STATE = 1,
130 BAD_STATE,
131 } GE_state_model;
132
133 /* Correlated Loss Generation models */
134 struct clgstate {
135 /* state of the Markov chain */
136 u8 state;
137
138 /* 4-states and Gilbert-Elliot models */
139 u32 a1; /* p13 for 4-states or p for GE */
140 u32 a2; /* p31 for 4-states or r for GE */
141 u32 a3; /* p32 for 4-states or h for GE */
142 u32 a4; /* p14 for 4-states or 1-k for GE */
143 u32 a5; /* p23 used only in 4-states */
144 } clg;
145
146 struct tc_netem_slot slot_config;
147 struct slotstate {
148 u64 slot_next;
149 s32 packets_left;
150 s32 bytes_left;
151 } slot;
152
153 struct disttable *slot_dist;
154 };
155
156 /* Time stamp put into socket buffer control block
157 * Only valid when skbs are in our internal t(ime)fifo queue.
158 *
159 * As skb->rbnode uses same storage than skb->next, skb->prev and skb->tstamp,
160 * and skb->next & skb->prev are scratch space for a qdisc,
161 * we save skb->tstamp value in skb->cb[] before destroying it.
162 */
163 struct netem_skb_cb {
164 u64 time_to_send;
165 };
166
167 static inline struct netem_skb_cb *netem_skb_cb(struct sk_buff *skb)
168 {
169 /* we assume we can use skb next/prev/tstamp as storage for rb_node */
170 qdisc_cb_private_validate(skb, sizeof(struct netem_skb_cb));
171 return (struct netem_skb_cb *)qdisc_skb_cb(skb)->data;
172 }
173
174 /* init_crandom - initialize correlated random number generator
175 * Use entropy source for initial seed.
176 */
177 static void init_crandom(struct crndstate *state, unsigned long rho)
178 {
179 state->rho = rho;
180 state->last = get_random_u32();
181 }
182
183 /* get_crandom - correlated random number generator
184 * Next number depends on last value.
185 * rho is scaled to avoid floating point.
186 */
187 static u32 get_crandom(struct crndstate *state, struct prng *p)
188 {
189 u64 value, rho;
190 unsigned long answer;
191 struct rnd_state *s = &p->prng_state;
192
193 if (!state || state->rho == 0) /* no correlation */
194 return prandom_u32_state(s);
195
196 value = prandom_u32_state(s);
197 rho = (u64)state->rho + 1;
198 answer = (value * ((1ull<<32) - rho) + state->last * rho) >> 32;
199 state->last = answer;
200 return answer;
201 }
202
203 /* loss_4state - 4-state model loss generator
204 * Generates losses according to the 4-state Markov chain adopted in
205 * the GI (General and Intuitive) loss model.
206 */
207 static bool loss_4state(struct netem_sched_data *q)
208 {
209 struct clgstate *clg = &q->clg;
210 u32 rnd = prandom_u32_state(&q->prng.prng_state);
211
212 /*
213 * Makes a comparison between rnd and the transition
214 * probabilities outgoing from the current state, then decides the
215 * next state and if the next packet has to be transmitted or lost.
216 * The four states correspond to:
217 * TX_IN_GAP_PERIOD => successfully transmitted packets within a gap period
218 * LOST_IN_GAP_PERIOD => isolated losses within a gap period
219 * LOST_IN_BURST_PERIOD => lost packets within a burst period
220 * TX_IN_BURST_PERIOD => successfully transmitted packets within a burst period
221 */
222 switch (clg->state) {
223 case TX_IN_GAP_PERIOD:
224 if (rnd < clg->a4) {
225 clg->state = LOST_IN_GAP_PERIOD;
226 return true;
227 } else if (clg->a4 < rnd && rnd < clg->a1 + clg->a4) {
228 clg->state = LOST_IN_BURST_PERIOD;
229 return true;
230 } else if (clg->a1 + clg->a4 < rnd) {
231 clg->state = TX_IN_GAP_PERIOD;
232 }
233
234 break;
235 case TX_IN_BURST_PERIOD:
236 if (rnd < clg->a5) {
237 clg->state = LOST_IN_BURST_PERIOD;
238 return true;
239 } else {
240 clg->state = TX_IN_BURST_PERIOD;
241 }
242
243 break;
244 case LOST_IN_BURST_PERIOD:
245 if (rnd < clg->a3)
246 clg->state = TX_IN_BURST_PERIOD;
247 else if (clg->a3 < rnd && rnd < clg->a2 + clg->a3) {
248 clg->state = TX_IN_GAP_PERIOD;
249 } else if (clg->a2 + clg->a3 < rnd) {
250 clg->state = LOST_IN_BURST_PERIOD;
251 return true;
252 }
253 break;
254 case LOST_IN_GAP_PERIOD:
255 clg->state = TX_IN_GAP_PERIOD;
256 break;
257 }
258
259 return false;
260 }
261
262 /* loss_gilb_ell - Gilbert-Elliot model loss generator
263 * Generates losses according to the Gilbert-Elliot loss model or
264 * its special cases (Gilbert or Simple Gilbert)
265 *
266 * Makes a comparison between random number and the transition
267 * probabilities outgoing from the current state, then decides the
268 * next state. A second random number is extracted and the comparison
269 * with the loss probability of the current state decides if the next
270 * packet will be transmitted or lost.
271 */
272 static bool loss_gilb_ell(struct netem_sched_data *q)
273 {
274 struct clgstate *clg = &q->clg;
275 struct rnd_state *s = &q->prng.prng_state;
276
277 switch (clg->state) {
278 case GOOD_STATE:
279 if (prandom_u32_state(s) < clg->a1)
280 clg->state = BAD_STATE;
281 if (prandom_u32_state(s) < clg->a4)
282 return true;
283 break;
284 case BAD_STATE:
285 if (prandom_u32_state(s) < clg->a2)
286 clg->state = GOOD_STATE;
287 if (prandom_u32_state(s) > clg->a3)
288 return true;
289 }
290
291 return false;
292 }
293
294 static bool loss_event(struct netem_sched_data *q)
295 {
296 switch (q->loss_model) {
297 case CLG_RANDOM:
298 /* Random packet drop 0 => none, ~0 => all */
299 return q->loss && q->loss >= get_crandom(&q->loss_cor, &q->prng);
300
301 case CLG_4_STATES:
302 /* 4state loss model algorithm (used also for GI model)
303 * Extracts a value from the markov 4 state 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_4state(q);
308
309 case CLG_GILB_ELL:
310 /* Gilbert-Elliot loss model algorithm
311 * Extracts a value from the Gilbert-Elliot loss generator,
312 * if it is 1 drops a packet and if needed writes the event in
313 * the kernel logs
314 */
315 return loss_gilb_ell(q);
316 }
317
318 return false; /* not reached */
319 }
320
321
322 /* tabledist - return a pseudo-randomly distributed value with mean mu and
323 * std deviation sigma. Uses table lookup to approximate the desired
324 * distribution, and a uniformly-distributed pseudo-random source.
325 */
326 static s64 tabledist(s64 mu, s32 sigma,
327 struct crndstate *state,
328 struct prng *prng,
329 const struct disttable *dist)
330 {
331 s64 x;
332 long t;
333 u32 rnd;
334
335 if (sigma == 0)
336 return mu;
337
338 rnd = get_crandom(state, prng);
339
340 /* default uniform distribution */
341 if (dist == NULL)
342 return ((rnd % (2 * (u32)sigma)) + mu) - sigma;
343
344 t = dist->table[rnd % dist->size];
345 x = (sigma % NETEM_DIST_SCALE) * t;
346 if (x >= 0)
347 x += NETEM_DIST_SCALE/2;
348 else
349 x -= NETEM_DIST_SCALE/2;
350
351 return x / NETEM_DIST_SCALE + (sigma / NETEM_DIST_SCALE) * t + mu;
352 }
353
354 static u64 packet_time_ns(u64 len, const struct netem_sched_data *q)
355 {
356 len += q->packet_overhead;
357
358 if (q->cell_size) {
359 u32 cells = reciprocal_divide(len, q->cell_size_reciprocal);
360
361 if (len > cells * q->cell_size) /* extra cell needed for remainder */
362 cells++;
363 len = cells * (q->cell_size + q->cell_overhead);
364 }
365
366 return div64_u64(len * NSEC_PER_SEC, q->rate);
367 }
368
369 static void tfifo_reset(struct Qdisc *sch)
370 {
371 struct netem_sched_data *q = qdisc_priv(sch);
372 struct rb_node *p = rb_first(&q->t_root);
373
374 while (p) {
375 struct sk_buff *skb = rb_to_skb(p);
376
377 p = rb_next(p);
378 rb_erase(&skb->rbnode, &q->t_root);
379 rtnl_kfree_skbs(skb, skb);
380 }
381
382 rtnl_kfree_skbs(q->t_head, q->t_tail);
383 q->t_head = NULL;
384 q->t_tail = NULL;
385 }
386
387 static void tfifo_enqueue(struct sk_buff *nskb, struct Qdisc *sch)
388 {
389 struct netem_sched_data *q = qdisc_priv(sch);
390 u64 tnext = netem_skb_cb(nskb)->time_to_send;
391
392 if (!q->t_tail || tnext >= netem_skb_cb(q->t_tail)->time_to_send) {
393 if (q->t_tail)
394 q->t_tail->next = nskb;
395 else
396 q->t_head = nskb;
397 q->t_tail = nskb;
398 } else {
399 struct rb_node **p = &q->t_root.rb_node, *parent = NULL;
400
401 while (*p) {
402 struct sk_buff *skb;
403
404 parent = *p;
405 skb = rb_to_skb(parent);
406 if (tnext >= netem_skb_cb(skb)->time_to_send)
407 p = &parent->rb_right;
408 else
409 p = &parent->rb_left;
410 }
411 rb_link_node(&nskb->rbnode, parent, p);
412 rb_insert_color(&nskb->rbnode, &q->t_root);
413 }
414 sch->q.qlen++;
415 }
416
417 /* netem can't properly corrupt a megapacket (like we get from GSO), so instead
418 * when we statistically choose to corrupt one, we instead segment it, returning
419 * the first packet to be corrupted, and re-enqueue the remaining frames
420 */
421 static struct sk_buff *netem_segment(struct sk_buff *skb, struct Qdisc *sch,
422 struct sk_buff **to_free)
423 {
424 struct sk_buff *segs;
425 netdev_features_t features = netif_skb_features(skb);
426
427 segs = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK);
428
429 if (IS_ERR_OR_NULL(segs)) {
430 qdisc_drop(skb, sch, to_free);
431 return NULL;
432 }
433 consume_skb(skb);
434 return segs;
435 }
436
437 /*
438 * Insert one skb into qdisc.
439 * Note: parent depends on return value to account for queue length.
440 * NET_XMIT_DROP: queue length didn't change.
441 * NET_XMIT_SUCCESS: one skb was queued.
442 */
443 static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
444 struct sk_buff **to_free)
445 {
446 struct netem_sched_data *q = qdisc_priv(sch);
447 /* We don't fill cb now as skb_unshare() may invalidate it */
448 struct netem_skb_cb *cb;
449 struct sk_buff *skb2 = NULL;
450 struct sk_buff *segs = NULL;
451 unsigned int prev_len = qdisc_pkt_len(skb);
452 int count = 1;
453
454 /* Do not fool qdisc_drop_all() */
455 skb->prev = NULL;
456
457 /* Random duplication */
458 if (q->duplicate && q->duplicate >= get_crandom(&q->dup_cor, &q->prng))
459 ++count;
460
461 /* Drop packet? */
462 if (loss_event(q)) {
463 if (q->ecn && INET_ECN_set_ce(skb))
464 qdisc_qstats_drop(sch); /* mark packet */
465 else
466 --count;
467 }
468 if (count == 0) {
469 qdisc_qstats_drop(sch);
470 __qdisc_drop(skb, to_free);
471 return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
472 }
473
474 /* If a delay is expected, orphan the skb. (orphaning usually takes
475 * place at TX completion time, so _before_ the link transit delay)
476 */
477 if (q->latency || q->jitter || q->rate)
478 skb_orphan_partial(skb);
479
480 /*
481 * If we need to duplicate packet, then clone it before
482 * original is modified.
483 */
484 if (count > 1)
485 skb2 = skb_clone(skb, GFP_ATOMIC);
486
487 /*
488 * Randomized packet corruption.
489 * Make copy if needed since we are modifying
490 * If packet is going to be hardware checksummed, then
491 * do it now in software before we mangle it.
492 */
493 if (q->corrupt && q->corrupt >= get_crandom(&q->corrupt_cor, &q->prng)) {
494 if (skb_is_gso(skb)) {
495 skb = netem_segment(skb, sch, to_free);
496 if (!skb)
497 goto finish_segs;
498
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 if (skb2)
525 __qdisc_drop(skb2, to_free);
526 return NET_XMIT_DROP;
527 }
528
529 /*
530 * If doing duplication then re-insert at top of the
531 * qdisc tree, since parent queuer expects that only one
532 * skb will be queued.
533 */
534 if (skb2) {
535 struct Qdisc *rootq = qdisc_root_bh(sch);
536 u32 dupsave = q->duplicate; /* prevent duplicating a dup... */
537
538 q->duplicate = 0;
539 rootq->enqueue(skb2, rootq, to_free);
540 q->duplicate = dupsave;
541 skb2 = NULL;
542 }
543
544 qdisc_qstats_backlog_inc(sch, skb);
545
546 cb = netem_skb_cb(skb);
547 if (q->gap == 0 || /* not doing reordering */
548 q->counter < q->gap - 1 || /* inside last reordering gap */
549 q->reorder < get_crandom(&q->reorder_cor, &q->prng)) {
550 u64 now;
551 s64 delay;
552
553 delay = tabledist(q->latency, q->jitter,
554 &q->delay_cor, &q->prng, q->delay_dist);
555
556 now = ktime_get_ns();
557
558 if (q->rate) {
559 struct netem_skb_cb *last = NULL;
560
561 if (sch->q.tail)
562 last = netem_skb_cb(sch->q.tail);
563 if (q->t_root.rb_node) {
564 struct sk_buff *t_skb;
565 struct netem_skb_cb *t_last;
566
567 t_skb = skb_rb_last(&q->t_root);
568 t_last = netem_skb_cb(t_skb);
569 if (!last ||
570 t_last->time_to_send > last->time_to_send)
571 last = t_last;
572 }
573 if (q->t_tail) {
574 struct netem_skb_cb *t_last =
575 netem_skb_cb(q->t_tail);
576
577 if (!last ||
578 t_last->time_to_send > last->time_to_send)
579 last = t_last;
580 }
581
582 if (last) {
583 /*
584 * Last packet in queue is reference point (now),
585 * calculate this time bonus and subtract
586 * from delay.
587 */
588 delay -= last->time_to_send - now;
589 delay = max_t(s64, 0, delay);
590 now = last->time_to_send;
591 }
592
593 delay += packet_time_ns(qdisc_pkt_len(skb), q);
594 }
595
596 cb->time_to_send = now + delay;
597 ++q->counter;
598 tfifo_enqueue(skb, sch);
599 } else {
600 /*
601 * Do re-ordering by putting one out of N packets at the front
602 * of the queue.
603 */
604 cb->time_to_send = ktime_get_ns();
605 q->counter = 0;
606
607 __qdisc_enqueue_head(skb, &sch->q);
608 sch->qstats.requeues++;
609 }
610
611 finish_segs:
612 if (skb2)
613 __qdisc_drop(skb2, to_free);
614
615 if (segs) {
616 unsigned int len, last_len;
617 int rc, nb;
618
619 len = skb ? skb->len : 0;
620 nb = skb ? 1 : 0;
621
622 while (segs) {
623 skb2 = segs->next;
624 skb_mark_not_on_list(segs);
625 qdisc_skb_cb(segs)->pkt_len = segs->len;
626 last_len = segs->len;
627 rc = qdisc_enqueue(segs, sch, to_free);
628 if (rc != NET_XMIT_SUCCESS) {
629 if (net_xmit_drop_count(rc))
630 qdisc_qstats_drop(sch);
631 } else {
632 nb++;
633 len += last_len;
634 }
635 segs = skb2;
636 }
637 /* Parent qdiscs accounted for 1 skb of size @prev_len */
638 qdisc_tree_reduce_backlog(sch, -(nb - 1), -(len - prev_len));
639 } else if (!skb) {
640 return NET_XMIT_DROP;
641 }
642 return NET_XMIT_SUCCESS;
643 }
644
645 /* Delay the next round with a new future slot with a
646 * correct number of bytes and packets.
647 */
648
649 static void get_slot_next(struct netem_sched_data *q, u64 now)
650 {
651 s64 next_delay;
652
653 if (!q->slot_dist)
654 next_delay = q->slot_config.min_delay +
655 (get_random_u32() *
656 (q->slot_config.max_delay -
657 q->slot_config.min_delay) >> 32);
658 else
659 next_delay = tabledist(q->slot_config.dist_delay,
660 (s32)(q->slot_config.dist_jitter),
661 NULL, &q->prng, q->slot_dist);
662
663 q->slot.slot_next = now + next_delay;
664 q->slot.packets_left = q->slot_config.max_packets;
665 q->slot.bytes_left = q->slot_config.max_bytes;
666 }
667
668 static struct sk_buff *netem_peek(struct netem_sched_data *q)
669 {
670 struct sk_buff *skb = skb_rb_first(&q->t_root);
671 u64 t1, t2;
672
673 if (!skb)
674 return q->t_head;
675 if (!q->t_head)
676 return skb;
677
678 t1 = netem_skb_cb(skb)->time_to_send;
679 t2 = netem_skb_cb(q->t_head)->time_to_send;
680 if (t1 < t2)
681 return skb;
682 return q->t_head;
683 }
684
685 static void netem_erase_head(struct netem_sched_data *q, struct sk_buff *skb)
686 {
687 if (skb == q->t_head) {
688 q->t_head = skb->next;
689 if (!q->t_head)
690 q->t_tail = NULL;
691 } else {
692 rb_erase(&skb->rbnode, &q->t_root);
693 }
694 }
695
696 static struct sk_buff *netem_dequeue(struct Qdisc *sch)
697 {
698 struct netem_sched_data *q = qdisc_priv(sch);
699 struct sk_buff *skb;
700
701 tfifo_dequeue:
702 skb = __qdisc_dequeue_head(&sch->q);
703 if (skb) {
704 qdisc_qstats_backlog_dec(sch, skb);
705 deliver:
706 qdisc_bstats_update(sch, skb);
707 return skb;
708 }
709 skb = netem_peek(q);
710 if (skb) {
711 u64 time_to_send;
712 u64 now = ktime_get_ns();
713
714 /* if more time remaining? */
715 time_to_send = netem_skb_cb(skb)->time_to_send;
716 if (q->slot.slot_next && q->slot.slot_next < time_to_send)
717 get_slot_next(q, now);
718
719 if (time_to_send <= now && q->slot.slot_next <= now) {
720 netem_erase_head(q, skb);
721 sch->q.qlen--;
722 qdisc_qstats_backlog_dec(sch, skb);
723 skb->next = NULL;
724 skb->prev = NULL;
725 /* skb->dev shares skb->rbnode area,
726 * we need to restore its value.
727 */
728 skb->dev = qdisc_dev(sch);
729
730 if (q->slot.slot_next) {
731 q->slot.packets_left--;
732 q->slot.bytes_left -= qdisc_pkt_len(skb);
733 if (q->slot.packets_left <= 0 ||
734 q->slot.bytes_left <= 0)
735 get_slot_next(q, now);
736 }
737
738 if (q->qdisc) {
739 unsigned int pkt_len = qdisc_pkt_len(skb);
740 struct sk_buff *to_free = NULL;
741 int err;
742
743 err = qdisc_enqueue(skb, q->qdisc, &to_free);
744 kfree_skb_list(to_free);
745 if (err != NET_XMIT_SUCCESS) {
746 if (net_xmit_drop_count(err))
747 qdisc_qstats_drop(sch);
748 qdisc_tree_reduce_backlog(sch, 1, pkt_len);
749 }
750 goto tfifo_dequeue;
751 }
752 goto deliver;
753 }
754
755 if (q->qdisc) {
756 skb = q->qdisc->ops->dequeue(q->qdisc);
757 if (skb)
758 goto deliver;
759 }
760
761 qdisc_watchdog_schedule_ns(&q->watchdog,
762 max(time_to_send,
763 q->slot.slot_next));
764 }
765
766 if (q->qdisc) {
767 skb = q->qdisc->ops->dequeue(q->qdisc);
768 if (skb)
769 goto deliver;
770 }
771 return NULL;
772 }
773
774 static void netem_reset(struct Qdisc *sch)
775 {
776 struct netem_sched_data *q = qdisc_priv(sch);
777
778 qdisc_reset_queue(sch);
779 tfifo_reset(sch);
780 if (q->qdisc)
781 qdisc_reset(q->qdisc);
782 qdisc_watchdog_cancel(&q->watchdog);
783 }
784
785 static void dist_free(struct disttable *d)
786 {
787 kvfree(d);
788 }
789
790 /*
791 * Distribution data is a variable size payload containing
792 * signed 16 bit values.
793 */
794
795 static int get_dist_table(struct disttable **tbl, const struct nlattr *attr)
796 {
797 size_t n = nla_len(attr)/sizeof(__s16);
798 const __s16 *data = nla_data(attr);
799 struct disttable *d;
800 int i;
801
802 if (!n || n > NETEM_DIST_MAX)
803 return -EINVAL;
804
805 d = kvmalloc(struct_size(d, table, n), GFP_KERNEL);
806 if (!d)
807 return -ENOMEM;
808
809 d->size = n;
810 for (i = 0; i < n; i++)
811 d->table[i] = data[i];
812
813 *tbl = d;
814 return 0;
815 }
816
817 static void get_slot(struct netem_sched_data *q, const struct nlattr *attr)
818 {
819 const struct tc_netem_slot *c = nla_data(attr);
820
821 q->slot_config = *c;
822 if (q->slot_config.max_packets == 0)
823 q->slot_config.max_packets = INT_MAX;
824 if (q->slot_config.max_bytes == 0)
825 q->slot_config.max_bytes = INT_MAX;
826
827 /* capping dist_jitter to the range acceptable by tabledist() */
828 q->slot_config.dist_jitter = min_t(__s64, INT_MAX, abs(q->slot_config.dist_jitter));
829
830 q->slot.packets_left = q->slot_config.max_packets;
831 q->slot.bytes_left = q->slot_config.max_bytes;
832 if (q->slot_config.min_delay | q->slot_config.max_delay |
833 q->slot_config.dist_jitter)
834 q->slot.slot_next = ktime_get_ns();
835 else
836 q->slot.slot_next = 0;
837 }
838
839 static void get_correlation(struct netem_sched_data *q, const struct nlattr *attr)
840 {
841 const struct tc_netem_corr *c = nla_data(attr);
842
843 init_crandom(&q->delay_cor, c->delay_corr);
844 init_crandom(&q->loss_cor, c->loss_corr);
845 init_crandom(&q->dup_cor, c->dup_corr);
846 }
847
848 static void get_reorder(struct netem_sched_data *q, const struct nlattr *attr)
849 {
850 const struct tc_netem_reorder *r = nla_data(attr);
851
852 q->reorder = r->probability;
853 init_crandom(&q->reorder_cor, r->correlation);
854 }
855
856 static void get_corrupt(struct netem_sched_data *q, const struct nlattr *attr)
857 {
858 const struct tc_netem_corrupt *r = nla_data(attr);
859
860 q->corrupt = r->probability;
861 init_crandom(&q->corrupt_cor, r->correlation);
862 }
863
864 static void get_rate(struct netem_sched_data *q, const struct nlattr *attr)
865 {
866 const struct tc_netem_rate *r = nla_data(attr);
867
868 q->rate = r->rate;
869 q->packet_overhead = r->packet_overhead;
870 q->cell_size = r->cell_size;
871 q->cell_overhead = r->cell_overhead;
872 if (q->cell_size)
873 q->cell_size_reciprocal = reciprocal_value(q->cell_size);
874 else
875 q->cell_size_reciprocal = (struct reciprocal_value) { 0 };
876 }
877
878 static int get_loss_clg(struct netem_sched_data *q, const struct nlattr *attr)
879 {
880 const struct nlattr *la;
881 int rem;
882
883 nla_for_each_nested(la, attr, rem) {
884 u16 type = nla_type(la);
885
886 switch (type) {
887 case NETEM_LOSS_GI: {
888 const struct tc_netem_gimodel *gi = nla_data(la);
889
890 if (nla_len(la) < sizeof(struct tc_netem_gimodel)) {
891 pr_info("netem: incorrect gi model size\n");
892 return -EINVAL;
893 }
894
895 q->loss_model = CLG_4_STATES;
896
897 q->clg.state = TX_IN_GAP_PERIOD;
898 q->clg.a1 = gi->p13;
899 q->clg.a2 = gi->p31;
900 q->clg.a3 = gi->p32;
901 q->clg.a4 = gi->p14;
902 q->clg.a5 = gi->p23;
903 break;
904 }
905
906 case NETEM_LOSS_GE: {
907 const struct tc_netem_gemodel *ge = nla_data(la);
908
909 if (nla_len(la) < sizeof(struct tc_netem_gemodel)) {
910 pr_info("netem: incorrect ge model size\n");
911 return -EINVAL;
912 }
913
914 q->loss_model = CLG_GILB_ELL;
915 q->clg.state = GOOD_STATE;
916 q->clg.a1 = ge->p;
917 q->clg.a2 = ge->r;
918 q->clg.a3 = ge->h;
919 q->clg.a4 = ge->k1;
920 break;
921 }
922
923 default:
924 pr_info("netem: unknown loss type %u\n", type);
925 return -EINVAL;
926 }
927 }
928
929 return 0;
930 }
931
932 static const struct nla_policy netem_policy[TCA_NETEM_MAX + 1] = {
933 [TCA_NETEM_CORR] = { .len = sizeof(struct tc_netem_corr) },
934 [TCA_NETEM_REORDER] = { .len = sizeof(struct tc_netem_reorder) },
935 [TCA_NETEM_CORRUPT] = { .len = sizeof(struct tc_netem_corrupt) },
936 [TCA_NETEM_RATE] = { .len = sizeof(struct tc_netem_rate) },
937 [TCA_NETEM_LOSS] = { .type = NLA_NESTED },
938 [TCA_NETEM_ECN] = { .type = NLA_U32 },
939 [TCA_NETEM_RATE64] = { .type = NLA_U64 },
940 [TCA_NETEM_LATENCY64] = { .type = NLA_S64 },
941 [TCA_NETEM_JITTER64] = { .type = NLA_S64 },
942 [TCA_NETEM_SLOT] = { .len = sizeof(struct tc_netem_slot) },
943 [TCA_NETEM_PRNG_SEED] = { .type = NLA_U64 },
944 };
945
946 static int parse_attr(struct nlattr *tb[], int maxtype, struct nlattr *nla,
947 const struct nla_policy *policy, int len)
948 {
949 int nested_len = nla_len(nla) - NLA_ALIGN(len);
950
951 if (nested_len < 0) {
952 pr_info("netem: invalid attributes len %d\n", nested_len);
953 return -EINVAL;
954 }
955
956 if (nested_len >= nla_attr_size(0))
957 return nla_parse_deprecated(tb, maxtype,
958 nla_data(nla) + NLA_ALIGN(len),
959 nested_len, policy, NULL);
960
961 memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
962 return 0;
963 }
964
965 /* Parse netlink message to set options */
966 static int netem_change(struct Qdisc *sch, struct nlattr *opt,
967 struct netlink_ext_ack *extack)
968 {
969 struct netem_sched_data *q = qdisc_priv(sch);
970 struct nlattr *tb[TCA_NETEM_MAX + 1];
971 struct disttable *delay_dist = NULL;
972 struct disttable *slot_dist = NULL;
973 struct tc_netem_qopt *qopt;
974 struct clgstate old_clg;
975 int old_loss_model = CLG_RANDOM;
976 int ret;
977
978 qopt = nla_data(opt);
979 ret = parse_attr(tb, TCA_NETEM_MAX, opt, netem_policy, sizeof(*qopt));
980 if (ret < 0)
981 return ret;
982
983 if (tb[TCA_NETEM_DELAY_DIST]) {
984 ret = get_dist_table(&delay_dist, tb[TCA_NETEM_DELAY_DIST]);
985 if (ret)
986 goto table_free;
987 }
988
989 if (tb[TCA_NETEM_SLOT_DIST]) {
990 ret = get_dist_table(&slot_dist, tb[TCA_NETEM_SLOT_DIST]);
991 if (ret)
992 goto table_free;
993 }
994
995 sch_tree_lock(sch);
996 /* backup q->clg and q->loss_model */
997 old_clg = q->clg;
998 old_loss_model = q->loss_model;
999
1000 if (tb[TCA_NETEM_LOSS]) {
1001 ret = get_loss_clg(q, tb[TCA_NETEM_LOSS]);
1002 if (ret) {
1003 q->loss_model = old_loss_model;
1004 q->clg = old_clg;
1005 goto unlock;
1006 }
1007 } else {
1008 q->loss_model = CLG_RANDOM;
1009 }
1010
1011 if (delay_dist)
1012 swap(q->delay_dist, delay_dist);
1013 if (slot_dist)
1014 swap(q->slot_dist, slot_dist);
1015 sch->limit = qopt->limit;
1016
1017 q->latency = PSCHED_TICKS2NS(qopt->latency);
1018 q->jitter = PSCHED_TICKS2NS(qopt->jitter);
1019 q->limit = qopt->limit;
1020 q->gap = qopt->gap;
1021 q->counter = 0;
1022 q->loss = qopt->loss;
1023 q->duplicate = qopt->duplicate;
1024
1025 /* for compatibility with earlier versions.
1026 * if gap is set, need to assume 100% probability
1027 */
1028 if (q->gap)
1029 q->reorder = ~0;
1030
1031 if (tb[TCA_NETEM_CORR])
1032 get_correlation(q, tb[TCA_NETEM_CORR]);
1033
1034 if (tb[TCA_NETEM_REORDER])
1035 get_reorder(q, tb[TCA_NETEM_REORDER]);
1036
1037 if (tb[TCA_NETEM_CORRUPT])
1038 get_corrupt(q, tb[TCA_NETEM_CORRUPT]);
1039
1040 if (tb[TCA_NETEM_RATE])
1041 get_rate(q, tb[TCA_NETEM_RATE]);
1042
1043 if (tb[TCA_NETEM_RATE64])
1044 q->rate = max_t(u64, q->rate,
1045 nla_get_u64(tb[TCA_NETEM_RATE64]));
1046
1047 if (tb[TCA_NETEM_LATENCY64])
1048 q->latency = nla_get_s64(tb[TCA_NETEM_LATENCY64]);
1049
1050 if (tb[TCA_NETEM_JITTER64])
1051 q->jitter = nla_get_s64(tb[TCA_NETEM_JITTER64]);
1052
1053 if (tb[TCA_NETEM_ECN])
1054 q->ecn = nla_get_u32(tb[TCA_NETEM_ECN]);
1055
1056 if (tb[TCA_NETEM_SLOT])
1057 get_slot(q, tb[TCA_NETEM_SLOT]);
1058
1059 /* capping jitter to the range acceptable by tabledist() */
1060 q->jitter = min_t(s64, abs(q->jitter), INT_MAX);
1061
1062 if (tb[TCA_NETEM_PRNG_SEED])
1063 q->prng.seed = nla_get_u64(tb[TCA_NETEM_PRNG_SEED]);
1064 else
1065 q->prng.seed = get_random_u64();
1066 prandom_seed_state(&q->prng.prng_state, q->prng.seed);
1067
1068 unlock:
1069 sch_tree_unlock(sch);
1070
1071 table_free:
1072 dist_free(delay_dist);
1073 dist_free(slot_dist);
1074 return ret;
1075 }
1076
1077 static int netem_init(struct Qdisc *sch, struct nlattr *opt,
1078 struct netlink_ext_ack *extack)
1079 {
1080 struct netem_sched_data *q = qdisc_priv(sch);
1081 int ret;
1082
1083 qdisc_watchdog_init(&q->watchdog, sch);
1084
1085 if (!opt)
1086 return -EINVAL;
1087
1088 q->loss_model = CLG_RANDOM;
1089 ret = netem_change(sch, opt, extack);
1090 if (ret)
1091 pr_info("netem: change failed\n");
1092 return ret;
1093 }
1094
1095 static void netem_destroy(struct Qdisc *sch)
1096 {
1097 struct netem_sched_data *q = qdisc_priv(sch);
1098
1099 qdisc_watchdog_cancel(&q->watchdog);
1100 if (q->qdisc)
1101 qdisc_put(q->qdisc);
1102 dist_free(q->delay_dist);
1103 dist_free(q->slot_dist);
1104 }
1105
1106 static int dump_loss_model(const struct netem_sched_data *q,
1107 struct sk_buff *skb)
1108 {
1109 struct nlattr *nest;
1110
1111 nest = nla_nest_start_noflag(skb, TCA_NETEM_LOSS);
1112 if (nest == NULL)
1113 goto nla_put_failure;
1114
1115 switch (q->loss_model) {
1116 case CLG_RANDOM:
1117 /* legacy loss model */
1118 nla_nest_cancel(skb, nest);
1119 return 0; /* no data */
1120
1121 case CLG_4_STATES: {
1122 struct tc_netem_gimodel gi = {
1123 .p13 = q->clg.a1,
1124 .p31 = q->clg.a2,
1125 .p32 = q->clg.a3,
1126 .p14 = q->clg.a4,
1127 .p23 = q->clg.a5,
1128 };
1129
1130 if (nla_put(skb, NETEM_LOSS_GI, sizeof(gi), &gi))
1131 goto nla_put_failure;
1132 break;
1133 }
1134 case CLG_GILB_ELL: {
1135 struct tc_netem_gemodel ge = {
1136 .p = q->clg.a1,
1137 .r = q->clg.a2,
1138 .h = q->clg.a3,
1139 .k1 = q->clg.a4,
1140 };
1141
1142 if (nla_put(skb, NETEM_LOSS_GE, sizeof(ge), &ge))
1143 goto nla_put_failure;
1144 break;
1145 }
1146 }
1147
1148 nla_nest_end(skb, nest);
1149 return 0;
1150
1151 nla_put_failure:
1152 nla_nest_cancel(skb, nest);
1153 return -1;
1154 }
1155
1156 static int netem_dump(struct Qdisc *sch, struct sk_buff *skb)
1157 {
1158 const struct netem_sched_data *q = qdisc_priv(sch);
1159 struct nlattr *nla = (struct nlattr *) skb_tail_pointer(skb);
1160 struct tc_netem_qopt qopt;
1161 struct tc_netem_corr cor;
1162 struct tc_netem_reorder reorder;
1163 struct tc_netem_corrupt corrupt;
1164 struct tc_netem_rate rate;
1165 struct tc_netem_slot slot;
1166
1167 qopt.latency = min_t(psched_time_t, PSCHED_NS2TICKS(q->latency),
1168 UINT_MAX);
1169 qopt.jitter = min_t(psched_time_t, PSCHED_NS2TICKS(q->jitter),
1170 UINT_MAX);
1171 qopt.limit = q->limit;
1172 qopt.loss = q->loss;
1173 qopt.gap = q->gap;
1174 qopt.duplicate = q->duplicate;
1175 if (nla_put(skb, TCA_OPTIONS, sizeof(qopt), &qopt))
1176 goto nla_put_failure;
1177
1178 if (nla_put(skb, TCA_NETEM_LATENCY64, sizeof(q->latency), &q->latency))
1179 goto nla_put_failure;
1180
1181 if (nla_put(skb, TCA_NETEM_JITTER64, sizeof(q->jitter), &q->jitter))
1182 goto nla_put_failure;
1183
1184 cor.delay_corr = q->delay_cor.rho;
1185 cor.loss_corr = q->loss_cor.rho;
1186 cor.dup_corr = q->dup_cor.rho;
1187 if (nla_put(skb, TCA_NETEM_CORR, sizeof(cor), &cor))
1188 goto nla_put_failure;
1189
1190 reorder.probability = q->reorder;
1191 reorder.correlation = q->reorder_cor.rho;
1192 if (nla_put(skb, TCA_NETEM_REORDER, sizeof(reorder), &reorder))
1193 goto nla_put_failure;
1194
1195 corrupt.probability = q->corrupt;
1196 corrupt.correlation = q->corrupt_cor.rho;
1197 if (nla_put(skb, TCA_NETEM_CORRUPT, sizeof(corrupt), &corrupt))
1198 goto nla_put_failure;
1199
1200 if (q->rate >= (1ULL << 32)) {
1201 if (nla_put_u64_64bit(skb, TCA_NETEM_RATE64, q->rate,
1202 TCA_NETEM_PAD))
1203 goto nla_put_failure;
1204 rate.rate = ~0U;
1205 } else {
1206 rate.rate = q->rate;
1207 }
1208 rate.packet_overhead = q->packet_overhead;
1209 rate.cell_size = q->cell_size;
1210 rate.cell_overhead = q->cell_overhead;
1211 if (nla_put(skb, TCA_NETEM_RATE, sizeof(rate), &rate))
1212 goto nla_put_failure;
1213
1214 if (q->ecn && nla_put_u32(skb, TCA_NETEM_ECN, q->ecn))
1215 goto nla_put_failure;
1216
1217 if (dump_loss_model(q, skb) != 0)
1218 goto nla_put_failure;
1219
1220 if (q->slot_config.min_delay | q->slot_config.max_delay |
1221 q->slot_config.dist_jitter) {
1222 slot = q->slot_config;
1223 if (slot.max_packets == INT_MAX)
1224 slot.max_packets = 0;
1225 if (slot.max_bytes == INT_MAX)
1226 slot.max_bytes = 0;
1227 if (nla_put(skb, TCA_NETEM_SLOT, sizeof(slot), &slot))
1228 goto nla_put_failure;
1229 }
1230
1231 if (nla_put_u64_64bit(skb, TCA_NETEM_PRNG_SEED, q->prng.seed,
1232 TCA_NETEM_PAD))
1233 goto nla_put_failure;
1234
1235 return nla_nest_end(skb, nla);
1236
1237 nla_put_failure:
1238 nlmsg_trim(skb, nla);
1239 return -1;
1240 }
1241
1242 static int netem_dump_class(struct Qdisc *sch, unsigned long cl,
1243 struct sk_buff *skb, struct tcmsg *tcm)
1244 {
1245 struct netem_sched_data *q = qdisc_priv(sch);
1246
1247 if (cl != 1 || !q->qdisc) /* only one class */
1248 return -ENOENT;
1249
1250 tcm->tcm_handle |= TC_H_MIN(1);
1251 tcm->tcm_info = q->qdisc->handle;
1252
1253 return 0;
1254 }
1255
1256 static int netem_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
1257 struct Qdisc **old, struct netlink_ext_ack *extack)
1258 {
1259 struct netem_sched_data *q = qdisc_priv(sch);
1260
1261 *old = qdisc_replace(sch, new, &q->qdisc);
1262 return 0;
1263 }
1264
1265 static struct Qdisc *netem_leaf(struct Qdisc *sch, unsigned long arg)
1266 {
1267 struct netem_sched_data *q = qdisc_priv(sch);
1268 return q->qdisc;
1269 }
1270
1271 static unsigned long netem_find(struct Qdisc *sch, u32 classid)
1272 {
1273 return 1;
1274 }
1275
1276 static void netem_walk(struct Qdisc *sch, struct qdisc_walker *walker)
1277 {
1278 if (!walker->stop) {
1279 if (!tc_qdisc_stats_dump(sch, 1, walker))
1280 return;
1281 }
1282 }
1283
1284 static const struct Qdisc_class_ops netem_class_ops = {
1285 .graft = netem_graft,
1286 .leaf = netem_leaf,
1287 .find = netem_find,
1288 .walk = netem_walk,
1289 .dump = netem_dump_class,
1290 };
1291
1292 static struct Qdisc_ops netem_qdisc_ops __read_mostly = {
1293 .id = "netem",
1294 .cl_ops = &netem_class_ops,
1295 .priv_size = sizeof(struct netem_sched_data),
1296 .enqueue = netem_enqueue,
1297 .dequeue = netem_dequeue,
1298 .peek = qdisc_peek_dequeued,
1299 .init = netem_init,
1300 .reset = netem_reset,
1301 .destroy = netem_destroy,
1302 .change = netem_change,
1303 .dump = netem_dump,
1304 .owner = THIS_MODULE,
1305 };
1306 MODULE_ALIAS_NET_SCH("netem");
1307
1308
1309 static int __init netem_module_init(void)
1310 {
1311 pr_info("netem: version " VERSION "\n");
1312 return register_qdisc(&netem_qdisc_ops);
1313 }
1314 static void __exit netem_module_exit(void)
1315 {
1316 unregister_qdisc(&netem_qdisc_ops);
1317 }
1318 module_init(netem_module_init)
1319 module_exit(netem_module_exit)
1320 MODULE_LICENSE("GPL");
1321 MODULE_DESCRIPTION("Network characteristics emulator qdisc");
Kernel DRM miscellaneous fixes and cross-tree changes