1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * net/sched/sch_netem.c Network emulator
4 *
5 * Many of the algorithms and ideas for this came from
6 * NIST Net which is not copyrighted.
7 *
8 * Authors: Stephen Hemminger <shemminger@osdl.org>
9 * Catalin(ux aka Dino) BOIE <catab at umbrella dot ro>
10 */
11
12 #include <linux/mm.h>
13 #include <linux/module.h>
14 #include <linux/slab.h>
15 #include <linux/types.h>
16 #include <linux/kernel.h>
17 #include <linux/errno.h>
18 #include <linux/skbuff.h>
19 #include <linux/vmalloc.h>
20 #include <linux/prandom.h>
21 #include <linux/rtnetlink.h>
22 #include <linux/reciprocal_div.h>
23 #include <linux/rbtree.h>
24
25 #include <net/gso.h>
26 #include <net/netlink.h>
27 #include <net/pkt_sched.h>
28 #include <net/inet_ecn.h>
29
30 #define VERSION "1.3"
31
32 /* Network Emulation Queuing algorithm.
33 ====================================
34
35 Sources: [1] Mark Carson, Darrin Santay, "NIST Net - A Linux-based
36 Network Emulation Tool
37 [2] Luigi Rizzo, DummyNet for FreeBSD
38
39 ----------------------------------------------------------------
40
41 This started out as a simple way to delay outgoing packets to
42 test TCP but has grown to include most of the functionality
43 of a full blown network emulator like NISTnet. It can delay
44 packets and add random jitter (and correlation). The random
45 distribution can be loaded from a table as well to provide
46 normal, Pareto, or experimental curves. Packet loss,
47 duplication, and reordering can also be emulated.
48
49 This qdisc does not do classification that can be handled in
50 layering other disciplines. It does not need to do bandwidth
51 control either since that can be handled by using token
52 bucket or other rate control.
53
54 Correlated Loss Generator models
55
56 Added generation of correlated loss according to the
57 "Gilbert-Elliot" model, a 4-state markov model.
58
59 References:
60 [1] NetemCLG Home http://netgroup.uniroma2.it/NetemCLG
61 [2] S. Salsano, F. Ludovici, A. Ordine, "Definition of a general
62 and intuitive loss model for packet networks and its implementation
63 in the Netem module in the Linux kernel", available in [1]
64
65 Authors: Stefano Salsano <stefano.salsano at uniroma2.it
66 Fabio Ludovici <fabio.ludovici at yahoo.it>
67 */
68
69 struct disttable {
70 u32 size;
71 s16 table[] __counted_by(size);
72 };
73
74 struct netem_sched_data {
75 /* internal t(ime)fifo qdisc uses t_root and sch->limit */
76 struct rb_root t_root;
77
78 /* a linear queue; reduces rbtree rebalancing when jitter is low */
79 struct sk_buff *t_head;
80 struct sk_buff *t_tail;
81
82 u32 t_len;
83
84 /* optional qdisc for classful handling (NULL at netem init) */
85 struct Qdisc *qdisc;
86
87 struct qdisc_watchdog watchdog;
88
89 s64 latency;
90 s64 jitter;
91
92 u32 loss;
93 u32 ecn;
94 u32 limit;
95 u32 counter;
96 u32 gap;
97 u32 duplicate;
98 u32 reorder;
99 u32 corrupt;
100 u64 rate;
101 s32 packet_overhead;
102 u32 cell_size;
103 struct reciprocal_value cell_size_reciprocal;
104 s32 cell_overhead;
105
106 struct crndstate {
107 u32 last;
108 u32 rho;
109 } delay_cor, loss_cor, dup_cor, reorder_cor, corrupt_cor;
110
111 struct prng {
112 u64 seed;
113 struct rnd_state prng_state;
114 } prng;
115
116 struct disttable *delay_dist;
117
118 enum {
119 CLG_RANDOM,
120 CLG_4_STATES,
121 CLG_GILB_ELL,
122 } loss_model;
123
124 enum {
125 TX_IN_GAP_PERIOD = 1,
126 TX_IN_BURST_PERIOD,
127 LOST_IN_GAP_PERIOD,
128 LOST_IN_BURST_PERIOD,
129 } _4_state_model;
130
131 enum {
132 GOOD_STATE = 1,
133 BAD_STATE,
134 } GE_state_model;
135
136 /* Correlated Loss Generation models */
137 struct clgstate {
138 /* state of the Markov chain */
139 u8 state;
140
141 /* 4-states and Gilbert-Elliot models */
142 u32 a1; /* p13 for 4-states or p for GE */
143 u32 a2; /* p31 for 4-states or r for GE */
144 u32 a3; /* p32 for 4-states or h for GE */
145 u32 a4; /* p14 for 4-states or 1-k for GE */
146 u32 a5; /* p23 used only in 4-states */
147 } clg;
148
149 struct tc_netem_slot slot_config;
150 struct slotstate {
151 u64 slot_next;
152 s32 packets_left;
153 s32 bytes_left;
154 } slot;
155
156 struct disttable *slot_dist;
157 };
158
159 /* Time stamp put into socket buffer control block
160 * Only valid when skbs are in our internal t(ime)fifo queue.
161 *
162 * As skb->rbnode uses same storage than skb->next, skb->prev and skb->tstamp,
163 * and skb->next & skb->prev are scratch space for a qdisc,
164 * we save skb->tstamp value in skb->cb[] before destroying it.
165 */
166 struct netem_skb_cb {
167 u64 time_to_send;
168 };
169
netem_skb_cb(struct sk_buff * skb)170 static inline struct netem_skb_cb *netem_skb_cb(struct sk_buff *skb)
171 {
172 /* we assume we can use skb next/prev/tstamp as storage for rb_node */
173 qdisc_cb_private_validate(skb, sizeof(struct netem_skb_cb));
174 return (struct netem_skb_cb *)qdisc_skb_cb(skb)->data;
175 }
176
177 /* init_crandom - initialize correlated random number generator
178 * Use entropy source for initial seed.
179 */
init_crandom(struct crndstate * state,unsigned long rho)180 static void init_crandom(struct crndstate *state, unsigned long rho)
181 {
182 state->rho = rho;
183 state->last = get_random_u32();
184 }
185
186 /* get_crandom - correlated random number generator
187 * Next number depends on last value.
188 * rho is scaled to avoid floating point.
189 */
get_crandom(struct crndstate * state,struct prng * p)190 static u32 get_crandom(struct crndstate *state, struct prng *p)
191 {
192 u64 value, rho;
193 unsigned long answer;
194 struct rnd_state *s = &p->prng_state;
195
196 if (!state || state->rho == 0) /* no correlation */
197 return prandom_u32_state(s);
198
199 value = prandom_u32_state(s);
200 rho = (u64)state->rho + 1;
201 answer = (value * ((1ull<<32) - rho) + state->last * rho) >> 32;
202 state->last = answer;
203 return answer;
204 }
205
206 /* loss_4state - 4-state model loss generator
207 * Generates losses according to the 4-state Markov chain adopted in
208 * the GI (General and Intuitive) loss model.
209 */
loss_4state(struct netem_sched_data * q)210 static bool loss_4state(struct netem_sched_data *q)
211 {
212 struct clgstate *clg = &q->clg;
213 u32 rnd = prandom_u32_state(&q->prng.prng_state);
214
215 /*
216 * Makes a comparison between rnd and the transition
217 * probabilities outgoing from the current state, then decides the
218 * next state and if the next packet has to be transmitted or lost.
219 * The four states correspond to:
220 * TX_IN_GAP_PERIOD => successfully transmitted packets within a gap period
221 * LOST_IN_GAP_PERIOD => isolated losses within a gap period
222 * LOST_IN_BURST_PERIOD => lost packets within a burst period
223 * TX_IN_BURST_PERIOD => successfully transmitted packets within a burst period
224 */
225 switch (clg->state) {
226 case TX_IN_GAP_PERIOD:
227 if (rnd < clg->a4) {
228 clg->state = LOST_IN_GAP_PERIOD;
229 return true;
230 } else if (rnd < clg->a1 + clg->a4) {
231 clg->state = LOST_IN_BURST_PERIOD;
232 return true;
233 } else {
234 clg->state = TX_IN_GAP_PERIOD;
235 }
236
237 break;
238 case TX_IN_BURST_PERIOD:
239 if (rnd < clg->a5) {
240 clg->state = LOST_IN_BURST_PERIOD;
241 return true;
242 } else {
243 clg->state = TX_IN_BURST_PERIOD;
244 }
245
246 break;
247 case LOST_IN_BURST_PERIOD:
248 if (rnd < clg->a3)
249 clg->state = TX_IN_BURST_PERIOD;
250 else if (rnd < clg->a2 + clg->a3) {
251 clg->state = TX_IN_GAP_PERIOD;
252 } else {
253 clg->state = LOST_IN_BURST_PERIOD;
254 return true;
255 }
256 break;
257 case LOST_IN_GAP_PERIOD:
258 clg->state = TX_IN_GAP_PERIOD;
259 break;
260 }
261
262 return false;
263 }
264
265 /* loss_gilb_ell - Gilbert-Elliot model loss generator
266 * Generates losses according to the Gilbert-Elliot loss model or
267 * its special cases (Gilbert or Simple Gilbert)
268 *
269 * Makes a comparison between random number and the transition
270 * probabilities outgoing from the current state, then decides the
271 * next state. A second random number is extracted and the comparison
272 * with the loss probability of the current state decides if the next
273 * packet will be transmitted or lost.
274 */
loss_gilb_ell(struct netem_sched_data * q)275 static bool loss_gilb_ell(struct netem_sched_data *q)
276 {
277 struct clgstate *clg = &q->clg;
278 struct rnd_state *s = &q->prng.prng_state;
279
280 switch (clg->state) {
281 case GOOD_STATE:
282 if (prandom_u32_state(s) < clg->a1)
283 clg->state = BAD_STATE;
284 if (prandom_u32_state(s) < clg->a4)
285 return true;
286 break;
287 case BAD_STATE:
288 if (prandom_u32_state(s) < clg->a2)
289 clg->state = GOOD_STATE;
290 if (prandom_u32_state(s) > clg->a3)
291 return true;
292 }
293
294 return false;
295 }
296
loss_event(struct netem_sched_data * q)297 static bool loss_event(struct netem_sched_data *q)
298 {
299 switch (q->loss_model) {
300 case CLG_RANDOM:
301 /* Random packet drop 0 => none, ~0 => all */
302 return q->loss && q->loss >= get_crandom(&q->loss_cor, &q->prng);
303
304 case CLG_4_STATES:
305 /* 4state loss model algorithm (used also for GI model)
306 * Extracts a value from the markov 4 state loss generator,
307 * if it is 1 drops a packet and if needed writes the event in
308 * the kernel logs
309 */
310 return loss_4state(q);
311
312 case CLG_GILB_ELL:
313 /* Gilbert-Elliot loss model algorithm
314 * Extracts a value from the Gilbert-Elliot loss generator,
315 * if it is 1 drops a packet and if needed writes the event in
316 * the kernel logs
317 */
318 return loss_gilb_ell(q);
319 }
320
321 return false; /* not reached */
322 }
323
324
325 /* tabledist - return a pseudo-randomly distributed value with mean mu and
326 * std deviation sigma. Uses table lookup to approximate the desired
327 * distribution, and a uniformly-distributed pseudo-random source.
328 */
tabledist(s64 mu,s32 sigma,struct crndstate * state,struct prng * prng,const struct disttable * dist)329 static s64 tabledist(s64 mu, s32 sigma,
330 struct crndstate *state,
331 struct prng *prng,
332 const struct disttable *dist)
333 {
334 s64 x;
335 long t;
336 u32 rnd;
337
338 if (sigma == 0)
339 return mu;
340
341 rnd = get_crandom(state, prng);
342
343 /* default uniform distribution */
344 if (dist == NULL)
345 return ((rnd % (2 * (u32)sigma)) + mu) - sigma;
346
347 t = dist->table[rnd % dist->size];
348 x = (sigma % NETEM_DIST_SCALE) * t;
349 if (x >= 0)
350 x += NETEM_DIST_SCALE/2;
351 else
352 x -= NETEM_DIST_SCALE/2;
353
354 return x / NETEM_DIST_SCALE + (sigma / NETEM_DIST_SCALE) * t + mu;
355 }
356
packet_time_ns(u64 len,const struct netem_sched_data * q)357 static u64 packet_time_ns(u64 len, const struct netem_sched_data *q)
358 {
359 len += q->packet_overhead;
360
361 if (q->cell_size) {
362 u32 cells = reciprocal_divide(len, q->cell_size_reciprocal);
363
364 if (len > cells * q->cell_size) /* extra cell needed for remainder */
365 cells++;
366 len = cells * (q->cell_size + q->cell_overhead);
367 }
368
369 return div64_u64(len * NSEC_PER_SEC, q->rate);
370 }
371
tfifo_reset(struct Qdisc * sch)372 static void tfifo_reset(struct Qdisc *sch)
373 {
374 struct netem_sched_data *q = qdisc_priv(sch);
375 struct rb_node *p = rb_first(&q->t_root);
376
377 while (p) {
378 struct sk_buff *skb = rb_to_skb(p);
379
380 p = rb_next(p);
381 rb_erase(&skb->rbnode, &q->t_root);
382 rtnl_kfree_skbs(skb, skb);
383 }
384
385 rtnl_kfree_skbs(q->t_head, q->t_tail);
386 q->t_head = NULL;
387 q->t_tail = NULL;
388 q->t_len = 0;
389 }
390
tfifo_enqueue(struct sk_buff * nskb,struct Qdisc * sch)391 static void tfifo_enqueue(struct sk_buff *nskb, struct Qdisc *sch)
392 {
393 struct netem_sched_data *q = qdisc_priv(sch);
394 u64 tnext = netem_skb_cb(nskb)->time_to_send;
395
396 if (!q->t_tail || tnext >= netem_skb_cb(q->t_tail)->time_to_send) {
397 if (q->t_tail)
398 q->t_tail->next = nskb;
399 else
400 q->t_head = nskb;
401 q->t_tail = nskb;
402 } else {
403 struct rb_node **p = &q->t_root.rb_node, *parent = NULL;
404
405 while (*p) {
406 struct sk_buff *skb;
407
408 parent = *p;
409 skb = rb_to_skb(parent);
410 if (tnext >= netem_skb_cb(skb)->time_to_send)
411 p = &parent->rb_right;
412 else
413 p = &parent->rb_left;
414 }
415 rb_link_node(&nskb->rbnode, parent, p);
416 rb_insert_color(&nskb->rbnode, &q->t_root);
417 }
418 q->t_len++;
419 sch->q.qlen++;
420 }
421
422 /* netem can't properly corrupt a megapacket (like we get from GSO), so instead
423 * when we statistically choose to corrupt one, we instead segment it, returning
424 * the first packet to be corrupted, and re-enqueue the remaining frames
425 */
netem_segment(struct sk_buff * skb,struct Qdisc * sch,struct sk_buff ** to_free)426 static struct sk_buff *netem_segment(struct sk_buff *skb, struct Qdisc *sch,
427 struct sk_buff **to_free)
428 {
429 struct sk_buff *segs;
430 netdev_features_t features = netif_skb_features(skb);
431
432 qdisc_skb_cb(skb)->pkt_segs = 1;
433 segs = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK);
434
435 if (IS_ERR_OR_NULL(segs)) {
436 qdisc_drop(skb, sch, to_free);
437 return NULL;
438 }
439 consume_skb(skb);
440 return segs;
441 }
442
443 /*
444 * Insert one skb into qdisc.
445 * Note: parent depends on return value to account for queue length.
446 * NET_XMIT_DROP: queue length didn't change.
447 * NET_XMIT_SUCCESS: one skb was queued.
448 */
netem_enqueue(struct sk_buff * skb,struct Qdisc * sch,struct sk_buff ** to_free)449 static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
450 struct sk_buff **to_free)
451 {
452 struct netem_sched_data *q = qdisc_priv(sch);
453 /* We don't fill cb now as skb_unshare() may invalidate it */
454 struct netem_skb_cb *cb;
455 struct sk_buff *skb2 = NULL;
456 struct sk_buff *segs = NULL;
457 unsigned int prev_len = qdisc_pkt_len(skb);
458 int count = 1;
459
460 /* Do not fool qdisc_drop_all() */
461 skb->prev = NULL;
462
463 /* Random duplication */
464 if (q->duplicate && q->duplicate >= get_crandom(&q->dup_cor, &q->prng))
465 ++count;
466
467 /* Drop packet? */
468 if (loss_event(q)) {
469 if (q->ecn && INET_ECN_set_ce(skb))
470 qdisc_qstats_drop(sch); /* mark packet */
471 else
472 --count;
473 }
474 if (count == 0) {
475 qdisc_qstats_drop(sch);
476 __qdisc_drop(skb, to_free);
477 return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
478 }
479
480 /* If a delay is expected, orphan the skb. (orphaning usually takes
481 * place at TX completion time, so _before_ the link transit delay)
482 */
483 if (q->latency || q->jitter || q->rate)
484 skb_orphan_partial(skb);
485
486 /*
487 * If we need to duplicate packet, then clone it before
488 * original is modified.
489 */
490 if (count > 1)
491 skb2 = skb_clone(skb, GFP_ATOMIC);
492
493 /*
494 * Randomized packet corruption.
495 * Make copy if needed since we are modifying
496 * If packet is going to be hardware checksummed, then
497 * do it now in software before we mangle it.
498 */
499 if (q->corrupt && q->corrupt >= get_crandom(&q->corrupt_cor, &q->prng)) {
500 if (skb_is_gso(skb)) {
501 skb = netem_segment(skb, sch, to_free);
502 if (!skb)
503 goto finish_segs;
504
505 segs = skb->next;
506 skb_mark_not_on_list(skb);
507 qdisc_skb_cb(skb)->pkt_len = skb->len;
508 }
509
510 skb = skb_unshare(skb, GFP_ATOMIC);
511 if (unlikely(!skb)) {
512 qdisc_qstats_drop(sch);
513 goto finish_segs;
514 }
515 if (skb->ip_summed == CHECKSUM_PARTIAL &&
516 skb_checksum_help(skb)) {
517 qdisc_drop(skb, sch, to_free);
518 skb = NULL;
519 goto finish_segs;
520 }
521
522 if (skb_headlen(skb))
523 skb->data[get_random_u32_below(skb_headlen(skb))] ^=
524 1 << get_random_u32_below(8);
525 }
526
527 if (unlikely(sch->q.qlen >= sch->limit)) {
528 /* re-link segs, so that qdisc_drop_all() frees them all */
529 skb->next = segs;
530 qdisc_drop_all(skb, sch, to_free);
531 if (skb2)
532 __qdisc_drop(skb2, to_free);
533 return NET_XMIT_DROP;
534 }
535
536 /*
537 * If doing duplication then re-insert at top of the
538 * qdisc tree, since parent queuer expects that only one
539 * skb will be queued.
540 */
541 if (skb2) {
542 struct Qdisc *rootq = qdisc_root_bh(sch);
543 u32 dupsave = q->duplicate; /* prevent duplicating a dup... */
544
545 q->duplicate = 0;
546 rootq->enqueue(skb2, rootq, to_free);
547 q->duplicate = dupsave;
548 skb2 = NULL;
549 }
550
551 qdisc_qstats_backlog_inc(sch, skb);
552
553 cb = netem_skb_cb(skb);
554 if (q->gap == 0 || /* not doing reordering */
555 q->counter < q->gap - 1 || /* inside last reordering gap */
556 q->reorder < get_crandom(&q->reorder_cor, &q->prng)) {
557 u64 now;
558 s64 delay;
559
560 delay = tabledist(q->latency, q->jitter,
561 &q->delay_cor, &q->prng, q->delay_dist);
562
563 now = ktime_get_ns();
564
565 if (q->rate) {
566 struct netem_skb_cb *last = NULL;
567
568 if (sch->q.tail)
569 last = netem_skb_cb(sch->q.tail);
570 if (q->t_root.rb_node) {
571 struct sk_buff *t_skb;
572 struct netem_skb_cb *t_last;
573
574 t_skb = skb_rb_last(&q->t_root);
575 t_last = netem_skb_cb(t_skb);
576 if (!last ||
577 t_last->time_to_send > last->time_to_send)
578 last = t_last;
579 }
580 if (q->t_tail) {
581 struct netem_skb_cb *t_last =
582 netem_skb_cb(q->t_tail);
583
584 if (!last ||
585 t_last->time_to_send > last->time_to_send)
586 last = t_last;
587 }
588
589 if (last) {
590 /*
591 * Last packet in queue is reference point (now),
592 * calculate this time bonus and subtract
593 * from delay.
594 */
595 delay -= last->time_to_send - now;
596 delay = max_t(s64, 0, delay);
597 now = last->time_to_send;
598 }
599
600 delay += packet_time_ns(qdisc_pkt_len(skb), q);
601 }
602
603 cb->time_to_send = now + delay;
604 ++q->counter;
605 tfifo_enqueue(skb, sch);
606 } else {
607 /*
608 * Do re-ordering by putting one out of N packets at the front
609 * of the queue.
610 */
611 cb->time_to_send = ktime_get_ns();
612 q->counter = 0;
613
614 __qdisc_enqueue_head(skb, &sch->q);
615 sch->qstats.requeues++;
616 }
617
618 finish_segs:
619 if (skb2)
620 __qdisc_drop(skb2, to_free);
621
622 if (segs) {
623 unsigned int len, last_len;
624 int rc, nb;
625
626 len = skb ? skb->len : 0;
627 nb = skb ? 1 : 0;
628
629 while (segs) {
630 skb2 = segs->next;
631 skb_mark_not_on_list(segs);
632 qdisc_skb_cb(segs)->pkt_len = segs->len;
633 last_len = segs->len;
634 rc = qdisc_enqueue(segs, sch, to_free);
635 if (rc != NET_XMIT_SUCCESS) {
636 if (net_xmit_drop_count(rc))
637 qdisc_qstats_drop(sch);
638 } else {
639 nb++;
640 len += last_len;
641 }
642 segs = skb2;
643 }
644 /* Parent qdiscs accounted for 1 skb of size @prev_len */
645 qdisc_tree_reduce_backlog(sch, -(nb - 1), -(len - prev_len));
646 } else if (!skb) {
647 return NET_XMIT_DROP;
648 }
649 return NET_XMIT_SUCCESS;
650 }
651
652 /* Delay the next round with a new future slot with a
653 * correct number of bytes and packets.
654 */
655
get_slot_next(struct netem_sched_data * q,u64 now)656 static void get_slot_next(struct netem_sched_data *q, u64 now)
657 {
658 s64 next_delay;
659
660 if (!q->slot_dist)
661 next_delay = q->slot_config.min_delay +
662 mul_u64_u32_shr(q->slot_config.max_delay - q->slot_config.min_delay,
663 get_random_u32(), 32);
664 else
665 next_delay = tabledist(q->slot_config.dist_delay,
666 (s32)(q->slot_config.dist_jitter),
667 NULL, &q->prng, q->slot_dist);
668
669 q->slot.slot_next = now + next_delay;
670 q->slot.packets_left = q->slot_config.max_packets;
671 q->slot.bytes_left = q->slot_config.max_bytes;
672 }
673
netem_peek(struct netem_sched_data * q)674 static struct sk_buff *netem_peek(struct netem_sched_data *q)
675 {
676 struct sk_buff *skb = skb_rb_first(&q->t_root);
677 u64 t1, t2;
678
679 if (!skb)
680 return q->t_head;
681 if (!q->t_head)
682 return skb;
683
684 t1 = netem_skb_cb(skb)->time_to_send;
685 t2 = netem_skb_cb(q->t_head)->time_to_send;
686 if (t1 < t2)
687 return skb;
688 return q->t_head;
689 }
690
netem_erase_head(struct netem_sched_data * q,struct sk_buff * skb)691 static void netem_erase_head(struct netem_sched_data *q, struct sk_buff *skb)
692 {
693 if (skb == q->t_head) {
694 q->t_head = skb->next;
695 if (!q->t_head)
696 q->t_tail = NULL;
697 } else {
698 rb_erase(&skb->rbnode, &q->t_root);
699 }
700 }
701
netem_dequeue(struct Qdisc * sch)702 static struct sk_buff *netem_dequeue(struct Qdisc *sch)
703 {
704 struct netem_sched_data *q = qdisc_priv(sch);
705 struct sk_buff *skb;
706
707 tfifo_dequeue:
708 skb = __qdisc_dequeue_head(&sch->q);
709 if (skb) {
710 deliver:
711 qdisc_qstats_backlog_dec(sch, skb);
712 qdisc_bstats_update(sch, skb);
713 return skb;
714 }
715 skb = netem_peek(q);
716 if (skb) {
717 u64 time_to_send;
718 u64 now = ktime_get_ns();
719
720 /* if more time remaining? */
721 time_to_send = netem_skb_cb(skb)->time_to_send;
722 if (q->slot.slot_next && q->slot.slot_next < time_to_send)
723 get_slot_next(q, now);
724
725 if (time_to_send <= now && q->slot.slot_next <= now) {
726 netem_erase_head(q, skb);
727 q->t_len--;
728 skb->next = NULL;
729 skb->prev = NULL;
730 /* skb->dev shares skb->rbnode area,
731 * we need to restore its value.
732 */
733 skb->dev = qdisc_dev(sch);
734
735 if (q->slot.slot_next) {
736 q->slot.packets_left--;
737 q->slot.bytes_left -= qdisc_pkt_len(skb);
738 if (q->slot.packets_left <= 0 ||
739 q->slot.bytes_left <= 0)
740 get_slot_next(q, now);
741 }
742
743 if (q->qdisc) {
744 unsigned int pkt_len = qdisc_pkt_len(skb);
745 struct sk_buff *to_free = NULL;
746 int err;
747
748 err = qdisc_enqueue(skb, q->qdisc, &to_free);
749 kfree_skb_list(to_free);
750 if (err != NET_XMIT_SUCCESS) {
751 if (net_xmit_drop_count(err))
752 qdisc_qstats_drop(sch);
753 sch->qstats.backlog -= pkt_len;
754 sch->q.qlen--;
755 qdisc_tree_reduce_backlog(sch, 1, pkt_len);
756 }
757 goto tfifo_dequeue;
758 }
759 sch->q.qlen--;
760 goto deliver;
761 }
762
763 if (q->qdisc) {
764 skb = q->qdisc->ops->dequeue(q->qdisc);
765 if (skb) {
766 sch->q.qlen--;
767 goto deliver;
768 }
769 }
770
771 qdisc_watchdog_schedule_ns(&q->watchdog,
772 max(time_to_send,
773 q->slot.slot_next));
774 }
775
776 if (q->qdisc) {
777 skb = q->qdisc->ops->dequeue(q->qdisc);
778 if (skb) {
779 sch->q.qlen--;
780 goto deliver;
781 }
782 }
783 return NULL;
784 }
785
netem_reset(struct Qdisc * sch)786 static void netem_reset(struct Qdisc *sch)
787 {
788 struct netem_sched_data *q = qdisc_priv(sch);
789
790 qdisc_reset_queue(sch);
791 tfifo_reset(sch);
792 if (q->qdisc)
793 qdisc_reset(q->qdisc);
794 qdisc_watchdog_cancel(&q->watchdog);
795 }
796
dist_free(struct disttable * d)797 static void dist_free(struct disttable *d)
798 {
799 kvfree(d);
800 }
801
802 /*
803 * Distribution data is a variable size payload containing
804 * signed 16 bit values.
805 */
806
get_dist_table(struct disttable ** tbl,const struct nlattr * attr)807 static int get_dist_table(struct disttable **tbl, const struct nlattr *attr)
808 {
809 size_t n = nla_len(attr)/sizeof(__s16);
810 const __s16 *data = nla_data(attr);
811 struct disttable *d;
812 int i;
813
814 if (!n || n > NETEM_DIST_MAX)
815 return -EINVAL;
816
817 d = kvmalloc_flex(*d, table, n);
818 if (!d)
819 return -ENOMEM;
820
821 d->size = n;
822 for (i = 0; i < n; i++)
823 d->table[i] = data[i];
824
825 *tbl = d;
826 return 0;
827 }
828
validate_time(const struct nlattr * attr,const char * name,struct netlink_ext_ack * extack)829 static int validate_time(const struct nlattr *attr, const char *name,
830 struct netlink_ext_ack *extack)
831 {
832 if (nla_get_s64(attr) < 0) {
833 NL_SET_ERR_MSG_ATTR_FMT(extack, attr, "negative %s", name);
834 return -EINVAL;
835 }
836 return 0;
837 }
838
validate_slot(const struct nlattr * attr,struct netlink_ext_ack * extack)839 static int validate_slot(const struct nlattr *attr, struct netlink_ext_ack *extack)
840 {
841 const struct tc_netem_slot *c = nla_data(attr);
842
843 if (c->min_delay < 0 || c->max_delay < 0) {
844 NL_SET_ERR_MSG_ATTR(extack, attr, "negative slot delay");
845 return -EINVAL;
846 }
847 if (c->min_delay > c->max_delay) {
848 NL_SET_ERR_MSG_ATTR(extack, attr, "slot min delay greater than max delay");
849 return -EINVAL;
850 }
851 if (c->dist_delay < 0 || c->dist_jitter < 0) {
852 NL_SET_ERR_MSG_ATTR(extack, attr, "negative dist delay");
853 return -EINVAL;
854 }
855 if (c->max_packets < 0 || c->max_bytes < 0) {
856 NL_SET_ERR_MSG_ATTR(extack, attr, "negative slot limit");
857 return -EINVAL;
858 }
859 return 0;
860 }
861
get_slot(struct netem_sched_data * q,const struct nlattr * attr)862 static void get_slot(struct netem_sched_data *q, const struct nlattr *attr)
863 {
864 const struct tc_netem_slot *c = nla_data(attr);
865
866 q->slot_config = *c;
867 if (q->slot_config.max_packets == 0)
868 q->slot_config.max_packets = INT_MAX;
869 if (q->slot_config.max_bytes == 0)
870 q->slot_config.max_bytes = INT_MAX;
871
872 /* capping dist_jitter to the range acceptable by tabledist() */
873 q->slot_config.dist_jitter = min_t(__s64, INT_MAX, abs(q->slot_config.dist_jitter));
874
875 q->slot.packets_left = q->slot_config.max_packets;
876 q->slot.bytes_left = q->slot_config.max_bytes;
877 if (q->slot_config.min_delay | q->slot_config.max_delay |
878 q->slot_config.dist_jitter)
879 q->slot.slot_next = ktime_get_ns();
880 else
881 q->slot.slot_next = 0;
882 }
883
get_correlation(struct netem_sched_data * q,const struct nlattr * attr)884 static void get_correlation(struct netem_sched_data *q, const struct nlattr *attr)
885 {
886 const struct tc_netem_corr *c = nla_data(attr);
887
888 init_crandom(&q->delay_cor, c->delay_corr);
889 init_crandom(&q->loss_cor, c->loss_corr);
890 init_crandom(&q->dup_cor, c->dup_corr);
891 }
892
get_reorder(struct netem_sched_data * q,const struct nlattr * attr)893 static void get_reorder(struct netem_sched_data *q, const struct nlattr *attr)
894 {
895 const struct tc_netem_reorder *r = nla_data(attr);
896
897 q->reorder = r->probability;
898 init_crandom(&q->reorder_cor, r->correlation);
899 }
900
get_corrupt(struct netem_sched_data * q,const struct nlattr * attr)901 static void get_corrupt(struct netem_sched_data *q, const struct nlattr *attr)
902 {
903 const struct tc_netem_corrupt *r = nla_data(attr);
904
905 q->corrupt = r->probability;
906 init_crandom(&q->corrupt_cor, r->correlation);
907 }
908
get_rate(struct netem_sched_data * q,const struct nlattr * attr)909 static void get_rate(struct netem_sched_data *q, const struct nlattr *attr)
910 {
911 const struct tc_netem_rate *r = nla_data(attr);
912
913 q->rate = r->rate;
914 q->packet_overhead = r->packet_overhead;
915 q->cell_size = r->cell_size;
916 q->cell_overhead = r->cell_overhead;
917 if (q->cell_size)
918 q->cell_size_reciprocal = reciprocal_value(q->cell_size);
919 else
920 q->cell_size_reciprocal = (struct reciprocal_value) { 0 };
921 }
922
get_loss_clg(struct netem_sched_data * q,const struct nlattr * attr)923 static int get_loss_clg(struct netem_sched_data *q, const struct nlattr *attr)
924 {
925 const struct nlattr *la;
926 int rem;
927
928 nla_for_each_nested(la, attr, rem) {
929 u16 type = nla_type(la);
930
931 switch (type) {
932 case NETEM_LOSS_GI: {
933 const struct tc_netem_gimodel *gi = nla_data(la);
934
935 if (nla_len(la) < sizeof(struct tc_netem_gimodel)) {
936 pr_info("netem: incorrect gi model size\n");
937 return -EINVAL;
938 }
939
940 q->loss_model = CLG_4_STATES;
941
942 q->clg.state = TX_IN_GAP_PERIOD;
943 q->clg.a1 = gi->p13;
944 q->clg.a2 = gi->p31;
945 q->clg.a3 = gi->p32;
946 q->clg.a4 = gi->p14;
947 q->clg.a5 = gi->p23;
948 break;
949 }
950
951 case NETEM_LOSS_GE: {
952 const struct tc_netem_gemodel *ge = nla_data(la);
953
954 if (nla_len(la) < sizeof(struct tc_netem_gemodel)) {
955 pr_info("netem: incorrect ge model size\n");
956 return -EINVAL;
957 }
958
959 q->loss_model = CLG_GILB_ELL;
960 q->clg.state = GOOD_STATE;
961 q->clg.a1 = ge->p;
962 q->clg.a2 = ge->r;
963 q->clg.a3 = ge->h;
964 q->clg.a4 = ge->k1;
965 break;
966 }
967
968 default:
969 pr_info("netem: unknown loss type %u\n", type);
970 return -EINVAL;
971 }
972 }
973
974 return 0;
975 }
976
977 static const struct nla_policy netem_policy[TCA_NETEM_MAX + 1] = {
978 [TCA_NETEM_CORR] = { .len = sizeof(struct tc_netem_corr) },
979 [TCA_NETEM_REORDER] = { .len = sizeof(struct tc_netem_reorder) },
980 [TCA_NETEM_CORRUPT] = { .len = sizeof(struct tc_netem_corrupt) },
981 [TCA_NETEM_RATE] = { .len = sizeof(struct tc_netem_rate) },
982 [TCA_NETEM_LOSS] = { .type = NLA_NESTED },
983 [TCA_NETEM_ECN] = { .type = NLA_U32 },
984 [TCA_NETEM_RATE64] = { .type = NLA_U64 },
985 [TCA_NETEM_LATENCY64] = { .type = NLA_S64 },
986 [TCA_NETEM_JITTER64] = { .type = NLA_S64 },
987 [TCA_NETEM_SLOT] = { .len = sizeof(struct tc_netem_slot) },
988 [TCA_NETEM_PRNG_SEED] = { .type = NLA_U64 },
989 };
990
parse_attr(struct nlattr * tb[],int maxtype,struct nlattr * nla,const struct nla_policy * policy,int len)991 static int parse_attr(struct nlattr *tb[], int maxtype, struct nlattr *nla,
992 const struct nla_policy *policy, int len)
993 {
994 int nested_len = nla_len(nla) - NLA_ALIGN(len);
995
996 if (nested_len < 0) {
997 pr_info("netem: invalid attributes len %d\n", nested_len);
998 return -EINVAL;
999 }
1000
1001 if (nested_len >= nla_attr_size(0))
1002 return nla_parse_deprecated(tb, maxtype,
1003 nla_data(nla) + NLA_ALIGN(len),
1004 nested_len, policy, NULL);
1005
1006 memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
1007 return 0;
1008 }
1009
1010 static const struct Qdisc_class_ops netem_class_ops;
1011
check_netem_in_tree(struct Qdisc * sch,bool duplicates,struct netlink_ext_ack * extack)1012 static int check_netem_in_tree(struct Qdisc *sch, bool duplicates,
1013 struct netlink_ext_ack *extack)
1014 {
1015 struct Qdisc *root, *q;
1016 unsigned int i;
1017
1018 root = qdisc_root_sleeping(sch);
1019
1020 if (sch != root && root->ops->cl_ops == &netem_class_ops) {
1021 if (duplicates ||
1022 ((struct netem_sched_data *)qdisc_priv(root))->duplicate)
1023 goto err;
1024 }
1025
1026 if (!qdisc_dev(root))
1027 return 0;
1028
1029 hash_for_each(qdisc_dev(root)->qdisc_hash, i, q, hash) {
1030 if (sch != q && q->ops->cl_ops == &netem_class_ops) {
1031 if (duplicates ||
1032 ((struct netem_sched_data *)qdisc_priv(q))->duplicate)
1033 goto err;
1034 }
1035 }
1036
1037 return 0;
1038
1039 err:
1040 NL_SET_ERR_MSG(extack,
1041 "netem: cannot mix duplicating netems with other netems in tree");
1042 return -EINVAL;
1043 }
1044
1045 /* Parse netlink message to set options */
netem_change(struct Qdisc * sch,struct nlattr * opt,struct netlink_ext_ack * extack)1046 static int netem_change(struct Qdisc *sch, struct nlattr *opt,
1047 struct netlink_ext_ack *extack)
1048 {
1049 struct netem_sched_data *q = qdisc_priv(sch);
1050 struct nlattr *tb[TCA_NETEM_MAX + 1];
1051 struct disttable *delay_dist = NULL;
1052 struct disttable *slot_dist = NULL;
1053 struct tc_netem_qopt *qopt;
1054 struct clgstate old_clg;
1055 int old_loss_model = CLG_RANDOM;
1056 int ret;
1057
1058 qopt = nla_data(opt);
1059 ret = parse_attr(tb, TCA_NETEM_MAX, opt, netem_policy, sizeof(*qopt));
1060 if (ret < 0)
1061 return ret;
1062
1063 if (tb[TCA_NETEM_DELAY_DIST]) {
1064 ret = get_dist_table(&delay_dist, tb[TCA_NETEM_DELAY_DIST]);
1065 if (ret)
1066 goto table_free;
1067 }
1068
1069 if (tb[TCA_NETEM_SLOT_DIST]) {
1070 ret = get_dist_table(&slot_dist, tb[TCA_NETEM_SLOT_DIST]);
1071 if (ret)
1072 goto table_free;
1073 }
1074
1075 if (tb[TCA_NETEM_SLOT]) {
1076 ret = validate_slot(tb[TCA_NETEM_SLOT], extack);
1077 if (ret)
1078 goto table_free;
1079 }
1080
1081 if (tb[TCA_NETEM_LATENCY64]) {
1082 ret = validate_time(tb[TCA_NETEM_LATENCY64], "latency", extack);
1083 if (ret)
1084 goto table_free;
1085 }
1086
1087 if (tb[TCA_NETEM_JITTER64]) {
1088 ret = validate_time(tb[TCA_NETEM_JITTER64], "jitter", extack);
1089 if (ret)
1090 goto table_free;
1091 }
1092
1093 sch_tree_lock(sch);
1094 /* backup q->clg and q->loss_model */
1095 old_clg = q->clg;
1096 old_loss_model = q->loss_model;
1097
1098 if (tb[TCA_NETEM_LOSS]) {
1099 ret = get_loss_clg(q, tb[TCA_NETEM_LOSS]);
1100 if (ret) {
1101 q->loss_model = old_loss_model;
1102 q->clg = old_clg;
1103 goto unlock;
1104 }
1105 } else {
1106 q->loss_model = CLG_RANDOM;
1107 }
1108
1109 if (delay_dist)
1110 swap(q->delay_dist, delay_dist);
1111 if (slot_dist)
1112 swap(q->slot_dist, slot_dist);
1113 sch->limit = qopt->limit;
1114
1115 q->latency = PSCHED_TICKS2NS(qopt->latency);
1116 q->jitter = PSCHED_TICKS2NS(qopt->jitter);
1117 q->limit = qopt->limit;
1118 q->gap = qopt->gap;
1119 q->counter = 0;
1120 q->loss = qopt->loss;
1121
1122 ret = check_netem_in_tree(sch, qopt->duplicate, extack);
1123 if (ret)
1124 goto unlock;
1125
1126 q->duplicate = qopt->duplicate;
1127
1128 /* for compatibility with earlier versions.
1129 * if gap is set, need to assume 100% probability
1130 */
1131 if (q->gap)
1132 q->reorder = ~0;
1133
1134 if (tb[TCA_NETEM_CORR])
1135 get_correlation(q, tb[TCA_NETEM_CORR]);
1136
1137 if (tb[TCA_NETEM_REORDER])
1138 get_reorder(q, tb[TCA_NETEM_REORDER]);
1139
1140 if (tb[TCA_NETEM_CORRUPT])
1141 get_corrupt(q, tb[TCA_NETEM_CORRUPT]);
1142
1143 if (tb[TCA_NETEM_RATE])
1144 get_rate(q, tb[TCA_NETEM_RATE]);
1145
1146 if (tb[TCA_NETEM_RATE64])
1147 q->rate = max_t(u64, q->rate,
1148 nla_get_u64(tb[TCA_NETEM_RATE64]));
1149
1150 if (tb[TCA_NETEM_LATENCY64])
1151 q->latency = nla_get_s64(tb[TCA_NETEM_LATENCY64]);
1152
1153 if (tb[TCA_NETEM_JITTER64])
1154 q->jitter = nla_get_s64(tb[TCA_NETEM_JITTER64]);
1155
1156 if (tb[TCA_NETEM_ECN])
1157 q->ecn = nla_get_u32(tb[TCA_NETEM_ECN]);
1158
1159 if (tb[TCA_NETEM_SLOT])
1160 get_slot(q, tb[TCA_NETEM_SLOT]);
1161
1162 /* capping jitter to the range acceptable by tabledist() */
1163 q->jitter = min_t(s64, abs(q->jitter), INT_MAX);
1164
1165 if (tb[TCA_NETEM_PRNG_SEED]) {
1166 q->prng.seed = nla_get_u64(tb[TCA_NETEM_PRNG_SEED]);
1167 prandom_seed_state(&q->prng.prng_state, q->prng.seed);
1168 }
1169
1170 unlock:
1171 sch_tree_unlock(sch);
1172
1173 table_free:
1174 dist_free(delay_dist);
1175 dist_free(slot_dist);
1176 return ret;
1177 }
1178
netem_init(struct Qdisc * sch,struct nlattr * opt,struct netlink_ext_ack * extack)1179 static int netem_init(struct Qdisc *sch, struct nlattr *opt,
1180 struct netlink_ext_ack *extack)
1181 {
1182 struct netem_sched_data *q = qdisc_priv(sch);
1183 int ret;
1184
1185 qdisc_watchdog_init(&q->watchdog, sch);
1186
1187 if (!opt)
1188 return -EINVAL;
1189
1190 q->loss_model = CLG_RANDOM;
1191 q->prng.seed = get_random_u64();
1192 prandom_seed_state(&q->prng.prng_state, q->prng.seed);
1193
1194 ret = netem_change(sch, opt, extack);
1195 if (ret)
1196 pr_info("netem: change failed\n");
1197 return ret;
1198 }
1199
netem_destroy(struct Qdisc * sch)1200 static void netem_destroy(struct Qdisc *sch)
1201 {
1202 struct netem_sched_data *q = qdisc_priv(sch);
1203
1204 qdisc_watchdog_cancel(&q->watchdog);
1205 if (q->qdisc)
1206 qdisc_put(q->qdisc);
1207 dist_free(q->delay_dist);
1208 dist_free(q->slot_dist);
1209 }
1210
dump_loss_model(const struct netem_sched_data * q,struct sk_buff * skb)1211 static int dump_loss_model(const struct netem_sched_data *q,
1212 struct sk_buff *skb)
1213 {
1214 struct nlattr *nest;
1215
1216 nest = nla_nest_start_noflag(skb, TCA_NETEM_LOSS);
1217 if (nest == NULL)
1218 goto nla_put_failure;
1219
1220 switch (q->loss_model) {
1221 case CLG_RANDOM:
1222 /* legacy loss model */
1223 nla_nest_cancel(skb, nest);
1224 return 0; /* no data */
1225
1226 case CLG_4_STATES: {
1227 struct tc_netem_gimodel gi = {
1228 .p13 = q->clg.a1,
1229 .p31 = q->clg.a2,
1230 .p32 = q->clg.a3,
1231 .p14 = q->clg.a4,
1232 .p23 = q->clg.a5,
1233 };
1234
1235 if (nla_put(skb, NETEM_LOSS_GI, sizeof(gi), &gi))
1236 goto nla_put_failure;
1237 break;
1238 }
1239 case CLG_GILB_ELL: {
1240 struct tc_netem_gemodel ge = {
1241 .p = q->clg.a1,
1242 .r = q->clg.a2,
1243 .h = q->clg.a3,
1244 .k1 = q->clg.a4,
1245 };
1246
1247 if (nla_put(skb, NETEM_LOSS_GE, sizeof(ge), &ge))
1248 goto nla_put_failure;
1249 break;
1250 }
1251 }
1252
1253 nla_nest_end(skb, nest);
1254 return 0;
1255
1256 nla_put_failure:
1257 nla_nest_cancel(skb, nest);
1258 return -1;
1259 }
1260
netem_dump(struct Qdisc * sch,struct sk_buff * skb)1261 static int netem_dump(struct Qdisc *sch, struct sk_buff *skb)
1262 {
1263 const struct netem_sched_data *q = qdisc_priv(sch);
1264 struct nlattr *nla = (struct nlattr *) skb_tail_pointer(skb);
1265 struct tc_netem_qopt qopt;
1266 struct tc_netem_corr cor;
1267 struct tc_netem_reorder reorder;
1268 struct tc_netem_corrupt corrupt;
1269 struct tc_netem_rate rate;
1270 struct tc_netem_slot slot;
1271
1272 qopt.latency = min_t(psched_time_t, PSCHED_NS2TICKS(q->latency),
1273 UINT_MAX);
1274 qopt.jitter = min_t(psched_time_t, PSCHED_NS2TICKS(q->jitter),
1275 UINT_MAX);
1276 qopt.limit = q->limit;
1277 qopt.loss = q->loss;
1278 qopt.gap = q->gap;
1279 qopt.duplicate = q->duplicate;
1280 if (nla_put(skb, TCA_OPTIONS, sizeof(qopt), &qopt))
1281 goto nla_put_failure;
1282
1283 if (nla_put(skb, TCA_NETEM_LATENCY64, sizeof(q->latency), &q->latency))
1284 goto nla_put_failure;
1285
1286 if (nla_put(skb, TCA_NETEM_JITTER64, sizeof(q->jitter), &q->jitter))
1287 goto nla_put_failure;
1288
1289 cor.delay_corr = q->delay_cor.rho;
1290 cor.loss_corr = q->loss_cor.rho;
1291 cor.dup_corr = q->dup_cor.rho;
1292 if (nla_put(skb, TCA_NETEM_CORR, sizeof(cor), &cor))
1293 goto nla_put_failure;
1294
1295 reorder.probability = q->reorder;
1296 reorder.correlation = q->reorder_cor.rho;
1297 if (nla_put(skb, TCA_NETEM_REORDER, sizeof(reorder), &reorder))
1298 goto nla_put_failure;
1299
1300 corrupt.probability = q->corrupt;
1301 corrupt.correlation = q->corrupt_cor.rho;
1302 if (nla_put(skb, TCA_NETEM_CORRUPT, sizeof(corrupt), &corrupt))
1303 goto nla_put_failure;
1304
1305 if (q->rate >= (1ULL << 32)) {
1306 if (nla_put_u64_64bit(skb, TCA_NETEM_RATE64, q->rate,
1307 TCA_NETEM_PAD))
1308 goto nla_put_failure;
1309 rate.rate = ~0U;
1310 } else {
1311 rate.rate = q->rate;
1312 }
1313 rate.packet_overhead = q->packet_overhead;
1314 rate.cell_size = q->cell_size;
1315 rate.cell_overhead = q->cell_overhead;
1316 if (nla_put(skb, TCA_NETEM_RATE, sizeof(rate), &rate))
1317 goto nla_put_failure;
1318
1319 if (q->ecn && nla_put_u32(skb, TCA_NETEM_ECN, q->ecn))
1320 goto nla_put_failure;
1321
1322 if (dump_loss_model(q, skb) != 0)
1323 goto nla_put_failure;
1324
1325 if (q->slot_config.min_delay | q->slot_config.max_delay |
1326 q->slot_config.dist_jitter) {
1327 slot = q->slot_config;
1328 if (slot.max_packets == INT_MAX)
1329 slot.max_packets = 0;
1330 if (slot.max_bytes == INT_MAX)
1331 slot.max_bytes = 0;
1332 if (nla_put(skb, TCA_NETEM_SLOT, sizeof(slot), &slot))
1333 goto nla_put_failure;
1334 }
1335
1336 if (nla_put_u64_64bit(skb, TCA_NETEM_PRNG_SEED, q->prng.seed,
1337 TCA_NETEM_PAD))
1338 goto nla_put_failure;
1339
1340 return nla_nest_end(skb, nla);
1341
1342 nla_put_failure:
1343 nlmsg_trim(skb, nla);
1344 return -1;
1345 }
1346
netem_dump_class(struct Qdisc * sch,unsigned long cl,struct sk_buff * skb,struct tcmsg * tcm)1347 static int netem_dump_class(struct Qdisc *sch, unsigned long cl,
1348 struct sk_buff *skb, struct tcmsg *tcm)
1349 {
1350 struct netem_sched_data *q = qdisc_priv(sch);
1351
1352 if (cl != 1 || !q->qdisc) /* only one class */
1353 return -ENOENT;
1354
1355 tcm->tcm_handle |= TC_H_MIN(1);
1356 tcm->tcm_info = q->qdisc->handle;
1357
1358 return 0;
1359 }
1360
netem_graft(struct Qdisc * sch,unsigned long arg,struct Qdisc * new,struct Qdisc ** old,struct netlink_ext_ack * extack)1361 static int netem_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
1362 struct Qdisc **old, struct netlink_ext_ack *extack)
1363 {
1364 struct netem_sched_data *q = qdisc_priv(sch);
1365
1366 *old = qdisc_replace(sch, new, &q->qdisc);
1367 return 0;
1368 }
1369
netem_leaf(struct Qdisc * sch,unsigned long arg)1370 static struct Qdisc *netem_leaf(struct Qdisc *sch, unsigned long arg)
1371 {
1372 struct netem_sched_data *q = qdisc_priv(sch);
1373 return q->qdisc;
1374 }
1375
netem_find(struct Qdisc * sch,u32 classid)1376 static unsigned long netem_find(struct Qdisc *sch, u32 classid)
1377 {
1378 return 1;
1379 }
1380
netem_walk(struct Qdisc * sch,struct qdisc_walker * walker)1381 static void netem_walk(struct Qdisc *sch, struct qdisc_walker *walker)
1382 {
1383 if (!walker->stop) {
1384 if (!tc_qdisc_stats_dump(sch, 1, walker))
1385 return;
1386 }
1387 }
1388
1389 static const struct Qdisc_class_ops netem_class_ops = {
1390 .graft = netem_graft,
1391 .leaf = netem_leaf,
1392 .find = netem_find,
1393 .walk = netem_walk,
1394 .dump = netem_dump_class,
1395 };
1396
1397 static struct Qdisc_ops netem_qdisc_ops __read_mostly = {
1398 .id = "netem",
1399 .cl_ops = &netem_class_ops,
1400 .priv_size = sizeof(struct netem_sched_data),
1401 .enqueue = netem_enqueue,
1402 .dequeue = netem_dequeue,
1403 .peek = qdisc_peek_dequeued,
1404 .init = netem_init,
1405 .reset = netem_reset,
1406 .destroy = netem_destroy,
1407 .change = netem_change,
1408 .dump = netem_dump,
1409 .owner = THIS_MODULE,
1410 };
1411 MODULE_ALIAS_NET_SCH("netem");
1412
1413
netem_module_init(void)1414 static int __init netem_module_init(void)
1415 {
1416 pr_info("netem: version " VERSION "\n");
1417 return register_qdisc(&netem_qdisc_ops);
1418 }
netem_module_exit(void)1419 static void __exit netem_module_exit(void)
1420 {
1421 unregister_qdisc(&netem_qdisc_ops);
1422 }
1423 module_init(netem_module_init)
1424 module_exit(netem_module_exit)
1425 MODULE_LICENSE("GPL");
1426 MODULE_DESCRIPTION("Network characteristics emulator qdisc");
1427