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[mirror_ubuntu-hirsute-kernel.git] / net / sched / sch_netem.c
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
71 struct netem_sched_data {
72 /* internal t(ime)fifo qdisc uses t_root and sch->limit */
73 struct rb_root t_root;
74
75 /* optional qdisc for classful handling (NULL at netem init) */
76 struct Qdisc *qdisc;
77
78 struct qdisc_watchdog watchdog;
79
80 psched_tdiff_t latency;
81 psched_tdiff_t jitter;
82
83 u32 loss;
84 u32 ecn;
85 u32 limit;
86 u32 counter;
87 u32 gap;
88 u32 duplicate;
89 u32 reorder;
90 u32 corrupt;
91 u64 rate;
92 s32 packet_overhead;
93 u32 cell_size;
94 struct reciprocal_value cell_size_reciprocal;
95 s32 cell_overhead;
96
97 struct crndstate {
98 u32 last;
99 u32 rho;
100 } delay_cor, loss_cor, dup_cor, reorder_cor, corrupt_cor;
101
102 struct disttable {
103 u32 size;
104 s16 table[0];
105 } *delay_dist;
106
107 enum {
108 CLG_RANDOM,
109 CLG_4_STATES,
110 CLG_GILB_ELL,
111 } loss_model;
112
113 enum {
114 TX_IN_GAP_PERIOD = 1,
115 TX_IN_BURST_PERIOD,
116 LOST_IN_GAP_PERIOD,
117 LOST_IN_BURST_PERIOD,
118 } _4_state_model;
119
120 enum {
121 GOOD_STATE = 1,
122 BAD_STATE,
123 } GE_state_model;
124
125 /* Correlated Loss Generation models */
126 struct clgstate {
127 /* state of the Markov chain */
128 u8 state;
129
130 /* 4-states and Gilbert-Elliot models */
131 u32 a1; /* p13 for 4-states or p for GE */
132 u32 a2; /* p31 for 4-states or r for GE */
133 u32 a3; /* p32 for 4-states or h for GE */
134 u32 a4; /* p14 for 4-states or 1-k for GE */
135 u32 a5; /* p23 used only in 4-states */
136 } clg;
137
138 };
139
140 /* Time stamp put into socket buffer control block
141 * Only valid when skbs are in our internal t(ime)fifo queue.
142 *
143 * As skb->rbnode uses same storage than skb->next, skb->prev and skb->tstamp,
144 * and skb->next & skb->prev are scratch space for a qdisc,
145 * we save skb->tstamp value in skb->cb[] before destroying it.
146 */
147 struct netem_skb_cb {
148 psched_time_t time_to_send;
149 ktime_t tstamp_save;
150 };
151
152
153 static struct sk_buff *netem_rb_to_skb(struct rb_node *rb)
154 {
155 return container_of(rb, struct sk_buff, rbnode);
156 }
157
158 static 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 */
168 static 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 */
178 static 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 */
197 static 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 */
262 static 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
283 static 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 */
315 static psched_tdiff_t tabledist(psched_tdiff_t mu, psched_tdiff_t sigma,
316 struct crndstate *state,
317 const struct disttable *dist)
318 {
319 psched_tdiff_t 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)) - sigma + mu;
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
342 static psched_time_t packet_len_2_sched_time(unsigned int len, struct netem_sched_data *q)
343 {
344 u64 ticks;
345
346 len += q->packet_overhead;
347
348 if (q->cell_size) {
349 u32 cells = reciprocal_divide(len, q->cell_size_reciprocal);
350
351 if (len > cells * q->cell_size) /* extra cell needed for remainder */
352 cells++;
353 len = cells * (q->cell_size + q->cell_overhead);
354 }
355
356 ticks = (u64)len * NSEC_PER_SEC;
357
358 do_div(ticks, q->rate);
359 return PSCHED_NS2TICKS(ticks);
360 }
361
362 static void tfifo_reset(struct Qdisc *sch)
363 {
364 struct netem_sched_data *q = qdisc_priv(sch);
365 struct rb_node *p;
366
367 while ((p = rb_first(&q->t_root))) {
368 struct sk_buff *skb = netem_rb_to_skb(p);
369
370 rb_erase(p, &q->t_root);
371 skb->next = NULL;
372 skb->prev = NULL;
373 kfree_skb(skb);
374 }
375 }
376
377 static void tfifo_enqueue(struct sk_buff *nskb, struct Qdisc *sch)
378 {
379 struct netem_sched_data *q = qdisc_priv(sch);
380 psched_time_t tnext = netem_skb_cb(nskb)->time_to_send;
381 struct rb_node **p = &q->t_root.rb_node, *parent = NULL;
382
383 while (*p) {
384 struct sk_buff *skb;
385
386 parent = *p;
387 skb = netem_rb_to_skb(parent);
388 if (tnext >= netem_skb_cb(skb)->time_to_send)
389 p = &parent->rb_right;
390 else
391 p = &parent->rb_left;
392 }
393 rb_link_node(&nskb->rbnode, parent, p);
394 rb_insert_color(&nskb->rbnode, &q->t_root);
395 sch->q.qlen++;
396 }
397
398 /*
399 * Insert one skb into qdisc.
400 * Note: parent depends on return value to account for queue length.
401 * NET_XMIT_DROP: queue length didn't change.
402 * NET_XMIT_SUCCESS: one skb was queued.
403 */
404 static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch)
405 {
406 struct netem_sched_data *q = qdisc_priv(sch);
407 /* We don't fill cb now as skb_unshare() may invalidate it */
408 struct netem_skb_cb *cb;
409 struct sk_buff *skb2;
410 int count = 1;
411
412 /* Random duplication */
413 if (q->duplicate && q->duplicate >= get_crandom(&q->dup_cor))
414 ++count;
415
416 /* Drop packet? */
417 if (loss_event(q)) {
418 if (q->ecn && INET_ECN_set_ce(skb))
419 qdisc_qstats_drop(sch); /* mark packet */
420 else
421 --count;
422 }
423 if (count == 0) {
424 qdisc_qstats_drop(sch);
425 kfree_skb(skb);
426 return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
427 }
428
429 /* If a delay is expected, orphan the skb. (orphaning usually takes
430 * place at TX completion time, so _before_ the link transit delay)
431 */
432 if (q->latency || q->jitter)
433 skb_orphan_partial(skb);
434
435 /*
436 * If we need to duplicate packet, then re-insert at top of the
437 * qdisc tree, since parent queuer expects that only one
438 * skb will be queued.
439 */
440 if (count > 1 && (skb2 = skb_clone(skb, GFP_ATOMIC)) != NULL) {
441 struct Qdisc *rootq = qdisc_root(sch);
442 u32 dupsave = q->duplicate; /* prevent duplicating a dup... */
443
444 q->duplicate = 0;
445 rootq->enqueue(skb2, rootq);
446 q->duplicate = dupsave;
447 }
448
449 /*
450 * Randomized packet corruption.
451 * Make copy if needed since we are modifying
452 * If packet is going to be hardware checksummed, then
453 * do it now in software before we mangle it.
454 */
455 if (q->corrupt && q->corrupt >= get_crandom(&q->corrupt_cor)) {
456 if (!(skb = skb_unshare(skb, GFP_ATOMIC)) ||
457 (skb->ip_summed == CHECKSUM_PARTIAL &&
458 skb_checksum_help(skb)))
459 return qdisc_drop(skb, sch);
460
461 skb->data[prandom_u32() % skb_headlen(skb)] ^=
462 1<<(prandom_u32() % 8);
463 }
464
465 if (unlikely(skb_queue_len(&sch->q) >= sch->limit))
466 return qdisc_reshape_fail(skb, sch);
467
468 qdisc_qstats_backlog_inc(sch, skb);
469
470 cb = netem_skb_cb(skb);
471 if (q->gap == 0 || /* not doing reordering */
472 q->counter < q->gap - 1 || /* inside last reordering gap */
473 q->reorder < get_crandom(&q->reorder_cor)) {
474 psched_time_t now;
475 psched_tdiff_t delay;
476
477 delay = tabledist(q->latency, q->jitter,
478 &q->delay_cor, q->delay_dist);
479
480 now = psched_get_time();
481
482 if (q->rate) {
483 struct sk_buff *last;
484
485 if (!skb_queue_empty(&sch->q))
486 last = skb_peek_tail(&sch->q);
487 else
488 last = netem_rb_to_skb(rb_last(&q->t_root));
489 if (last) {
490 /*
491 * Last packet in queue is reference point (now),
492 * calculate this time bonus and subtract
493 * from delay.
494 */
495 delay -= netem_skb_cb(last)->time_to_send - now;
496 delay = max_t(psched_tdiff_t, 0, delay);
497 now = netem_skb_cb(last)->time_to_send;
498 }
499
500 delay += packet_len_2_sched_time(qdisc_pkt_len(skb), q);
501 }
502
503 cb->time_to_send = now + delay;
504 cb->tstamp_save = skb->tstamp;
505 ++q->counter;
506 tfifo_enqueue(skb, sch);
507 } else {
508 /*
509 * Do re-ordering by putting one out of N packets at the front
510 * of the queue.
511 */
512 cb->time_to_send = psched_get_time();
513 q->counter = 0;
514
515 __skb_queue_head(&sch->q, skb);
516 sch->qstats.requeues++;
517 }
518
519 return NET_XMIT_SUCCESS;
520 }
521
522 static unsigned int netem_drop(struct Qdisc *sch)
523 {
524 struct netem_sched_data *q = qdisc_priv(sch);
525 unsigned int len;
526
527 len = qdisc_queue_drop(sch);
528
529 if (!len) {
530 struct rb_node *p = rb_first(&q->t_root);
531
532 if (p) {
533 struct sk_buff *skb = netem_rb_to_skb(p);
534
535 rb_erase(p, &q->t_root);
536 sch->q.qlen--;
537 skb->next = NULL;
538 skb->prev = NULL;
539 qdisc_qstats_backlog_dec(sch, skb);
540 kfree_skb(skb);
541 }
542 }
543 if (!len && q->qdisc && q->qdisc->ops->drop)
544 len = q->qdisc->ops->drop(q->qdisc);
545 if (len)
546 qdisc_qstats_drop(sch);
547
548 return len;
549 }
550
551 static struct sk_buff *netem_dequeue(struct Qdisc *sch)
552 {
553 struct netem_sched_data *q = qdisc_priv(sch);
554 struct sk_buff *skb;
555 struct rb_node *p;
556
557 if (qdisc_is_throttled(sch))
558 return NULL;
559
560 tfifo_dequeue:
561 skb = __skb_dequeue(&sch->q);
562 if (skb) {
563 qdisc_qstats_backlog_dec(sch, skb);
564 deliver:
565 qdisc_unthrottled(sch);
566 qdisc_bstats_update(sch, skb);
567 return skb;
568 }
569 p = rb_first(&q->t_root);
570 if (p) {
571 psched_time_t time_to_send;
572
573 skb = netem_rb_to_skb(p);
574
575 /* if more time remaining? */
576 time_to_send = netem_skb_cb(skb)->time_to_send;
577 if (time_to_send <= psched_get_time()) {
578 rb_erase(p, &q->t_root);
579
580 sch->q.qlen--;
581 qdisc_qstats_backlog_dec(sch, skb);
582 skb->next = NULL;
583 skb->prev = NULL;
584 skb->tstamp = netem_skb_cb(skb)->tstamp_save;
585
586 #ifdef CONFIG_NET_CLS_ACT
587 /*
588 * If it's at ingress let's pretend the delay is
589 * from the network (tstamp will be updated).
590 */
591 if (G_TC_FROM(skb->tc_verd) & AT_INGRESS)
592 skb->tstamp.tv64 = 0;
593 #endif
594
595 if (q->qdisc) {
596 int err = qdisc_enqueue(skb, q->qdisc);
597
598 if (unlikely(err != NET_XMIT_SUCCESS)) {
599 if (net_xmit_drop_count(err)) {
600 qdisc_qstats_drop(sch);
601 qdisc_tree_reduce_backlog(sch, 1,
602 qdisc_pkt_len(skb));
603 }
604 }
605 goto tfifo_dequeue;
606 }
607 goto deliver;
608 }
609
610 if (q->qdisc) {
611 skb = q->qdisc->ops->dequeue(q->qdisc);
612 if (skb)
613 goto deliver;
614 }
615 qdisc_watchdog_schedule(&q->watchdog, time_to_send);
616 }
617
618 if (q->qdisc) {
619 skb = q->qdisc->ops->dequeue(q->qdisc);
620 if (skb)
621 goto deliver;
622 }
623 return NULL;
624 }
625
626 static void netem_reset(struct Qdisc *sch)
627 {
628 struct netem_sched_data *q = qdisc_priv(sch);
629
630 qdisc_reset_queue(sch);
631 tfifo_reset(sch);
632 if (q->qdisc)
633 qdisc_reset(q->qdisc);
634 qdisc_watchdog_cancel(&q->watchdog);
635 }
636
637 static void dist_free(struct disttable *d)
638 {
639 kvfree(d);
640 }
641
642 /*
643 * Distribution data is a variable size payload containing
644 * signed 16 bit values.
645 */
646 static int get_dist_table(struct Qdisc *sch, const struct nlattr *attr)
647 {
648 struct netem_sched_data *q = qdisc_priv(sch);
649 size_t n = nla_len(attr)/sizeof(__s16);
650 const __s16 *data = nla_data(attr);
651 spinlock_t *root_lock;
652 struct disttable *d;
653 int i;
654 size_t s;
655
656 if (n > NETEM_DIST_MAX)
657 return -EINVAL;
658
659 s = sizeof(struct disttable) + n * sizeof(s16);
660 d = kmalloc(s, GFP_KERNEL | __GFP_NOWARN);
661 if (!d)
662 d = vmalloc(s);
663 if (!d)
664 return -ENOMEM;
665
666 d->size = n;
667 for (i = 0; i < n; i++)
668 d->table[i] = data[i];
669
670 root_lock = qdisc_root_sleeping_lock(sch);
671
672 spin_lock_bh(root_lock);
673 swap(q->delay_dist, d);
674 spin_unlock_bh(root_lock);
675
676 dist_free(d);
677 return 0;
678 }
679
680 static void get_correlation(struct netem_sched_data *q, const struct nlattr *attr)
681 {
682 const struct tc_netem_corr *c = nla_data(attr);
683
684 init_crandom(&q->delay_cor, c->delay_corr);
685 init_crandom(&q->loss_cor, c->loss_corr);
686 init_crandom(&q->dup_cor, c->dup_corr);
687 }
688
689 static void get_reorder(struct netem_sched_data *q, const struct nlattr *attr)
690 {
691 const struct tc_netem_reorder *r = nla_data(attr);
692
693 q->reorder = r->probability;
694 init_crandom(&q->reorder_cor, r->correlation);
695 }
696
697 static void get_corrupt(struct netem_sched_data *q, const struct nlattr *attr)
698 {
699 const struct tc_netem_corrupt *r = nla_data(attr);
700
701 q->corrupt = r->probability;
702 init_crandom(&q->corrupt_cor, r->correlation);
703 }
704
705 static void get_rate(struct netem_sched_data *q, const struct nlattr *attr)
706 {
707 const struct tc_netem_rate *r = nla_data(attr);
708
709 q->rate = r->rate;
710 q->packet_overhead = r->packet_overhead;
711 q->cell_size = r->cell_size;
712 q->cell_overhead = r->cell_overhead;
713 if (q->cell_size)
714 q->cell_size_reciprocal = reciprocal_value(q->cell_size);
715 else
716 q->cell_size_reciprocal = (struct reciprocal_value) { 0 };
717 }
718
719 static int get_loss_clg(struct netem_sched_data *q, const struct nlattr *attr)
720 {
721 const struct nlattr *la;
722 int rem;
723
724 nla_for_each_nested(la, attr, rem) {
725 u16 type = nla_type(la);
726
727 switch (type) {
728 case NETEM_LOSS_GI: {
729 const struct tc_netem_gimodel *gi = nla_data(la);
730
731 if (nla_len(la) < sizeof(struct tc_netem_gimodel)) {
732 pr_info("netem: incorrect gi model size\n");
733 return -EINVAL;
734 }
735
736 q->loss_model = CLG_4_STATES;
737
738 q->clg.state = TX_IN_GAP_PERIOD;
739 q->clg.a1 = gi->p13;
740 q->clg.a2 = gi->p31;
741 q->clg.a3 = gi->p32;
742 q->clg.a4 = gi->p14;
743 q->clg.a5 = gi->p23;
744 break;
745 }
746
747 case NETEM_LOSS_GE: {
748 const struct tc_netem_gemodel *ge = nla_data(la);
749
750 if (nla_len(la) < sizeof(struct tc_netem_gemodel)) {
751 pr_info("netem: incorrect ge model size\n");
752 return -EINVAL;
753 }
754
755 q->loss_model = CLG_GILB_ELL;
756 q->clg.state = GOOD_STATE;
757 q->clg.a1 = ge->p;
758 q->clg.a2 = ge->r;
759 q->clg.a3 = ge->h;
760 q->clg.a4 = ge->k1;
761 break;
762 }
763
764 default:
765 pr_info("netem: unknown loss type %u\n", type);
766 return -EINVAL;
767 }
768 }
769
770 return 0;
771 }
772
773 static const struct nla_policy netem_policy[TCA_NETEM_MAX + 1] = {
774 [TCA_NETEM_CORR] = { .len = sizeof(struct tc_netem_corr) },
775 [TCA_NETEM_REORDER] = { .len = sizeof(struct tc_netem_reorder) },
776 [TCA_NETEM_CORRUPT] = { .len = sizeof(struct tc_netem_corrupt) },
777 [TCA_NETEM_RATE] = { .len = sizeof(struct tc_netem_rate) },
778 [TCA_NETEM_LOSS] = { .type = NLA_NESTED },
779 [TCA_NETEM_ECN] = { .type = NLA_U32 },
780 [TCA_NETEM_RATE64] = { .type = NLA_U64 },
781 };
782
783 static int parse_attr(struct nlattr *tb[], int maxtype, struct nlattr *nla,
784 const struct nla_policy *policy, int len)
785 {
786 int nested_len = nla_len(nla) - NLA_ALIGN(len);
787
788 if (nested_len < 0) {
789 pr_info("netem: invalid attributes len %d\n", nested_len);
790 return -EINVAL;
791 }
792
793 if (nested_len >= nla_attr_size(0))
794 return nla_parse(tb, maxtype, nla_data(nla) + NLA_ALIGN(len),
795 nested_len, policy);
796
797 memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
798 return 0;
799 }
800
801 /* Parse netlink message to set options */
802 static int netem_change(struct Qdisc *sch, struct nlattr *opt)
803 {
804 struct netem_sched_data *q = qdisc_priv(sch);
805 struct nlattr *tb[TCA_NETEM_MAX + 1];
806 struct tc_netem_qopt *qopt;
807 struct clgstate old_clg;
808 int old_loss_model = CLG_RANDOM;
809 int ret;
810
811 if (opt == NULL)
812 return -EINVAL;
813
814 qopt = nla_data(opt);
815 ret = parse_attr(tb, TCA_NETEM_MAX, opt, netem_policy, sizeof(*qopt));
816 if (ret < 0)
817 return ret;
818
819 /* backup q->clg and q->loss_model */
820 old_clg = q->clg;
821 old_loss_model = q->loss_model;
822
823 if (tb[TCA_NETEM_LOSS]) {
824 ret = get_loss_clg(q, tb[TCA_NETEM_LOSS]);
825 if (ret) {
826 q->loss_model = old_loss_model;
827 return ret;
828 }
829 } else {
830 q->loss_model = CLG_RANDOM;
831 }
832
833 if (tb[TCA_NETEM_DELAY_DIST]) {
834 ret = get_dist_table(sch, tb[TCA_NETEM_DELAY_DIST]);
835 if (ret) {
836 /* recover clg and loss_model, in case of
837 * q->clg and q->loss_model were modified
838 * in get_loss_clg()
839 */
840 q->clg = old_clg;
841 q->loss_model = old_loss_model;
842 return ret;
843 }
844 }
845
846 sch->limit = qopt->limit;
847
848 q->latency = qopt->latency;
849 q->jitter = qopt->jitter;
850 q->limit = qopt->limit;
851 q->gap = qopt->gap;
852 q->counter = 0;
853 q->loss = qopt->loss;
854 q->duplicate = qopt->duplicate;
855
856 /* for compatibility with earlier versions.
857 * if gap is set, need to assume 100% probability
858 */
859 if (q->gap)
860 q->reorder = ~0;
861
862 if (tb[TCA_NETEM_CORR])
863 get_correlation(q, tb[TCA_NETEM_CORR]);
864
865 if (tb[TCA_NETEM_REORDER])
866 get_reorder(q, tb[TCA_NETEM_REORDER]);
867
868 if (tb[TCA_NETEM_CORRUPT])
869 get_corrupt(q, tb[TCA_NETEM_CORRUPT]);
870
871 if (tb[TCA_NETEM_RATE])
872 get_rate(q, tb[TCA_NETEM_RATE]);
873
874 if (tb[TCA_NETEM_RATE64])
875 q->rate = max_t(u64, q->rate,
876 nla_get_u64(tb[TCA_NETEM_RATE64]));
877
878 if (tb[TCA_NETEM_ECN])
879 q->ecn = nla_get_u32(tb[TCA_NETEM_ECN]);
880
881 return ret;
882 }
883
884 static int netem_init(struct Qdisc *sch, struct nlattr *opt)
885 {
886 struct netem_sched_data *q = qdisc_priv(sch);
887 int ret;
888
889 if (!opt)
890 return -EINVAL;
891
892 qdisc_watchdog_init(&q->watchdog, sch);
893
894 q->loss_model = CLG_RANDOM;
895 ret = netem_change(sch, opt);
896 if (ret)
897 pr_info("netem: change failed\n");
898 return ret;
899 }
900
901 static void netem_destroy(struct Qdisc *sch)
902 {
903 struct netem_sched_data *q = qdisc_priv(sch);
904
905 qdisc_watchdog_cancel(&q->watchdog);
906 if (q->qdisc)
907 qdisc_destroy(q->qdisc);
908 dist_free(q->delay_dist);
909 }
910
911 static int dump_loss_model(const struct netem_sched_data *q,
912 struct sk_buff *skb)
913 {
914 struct nlattr *nest;
915
916 nest = nla_nest_start(skb, TCA_NETEM_LOSS);
917 if (nest == NULL)
918 goto nla_put_failure;
919
920 switch (q->loss_model) {
921 case CLG_RANDOM:
922 /* legacy loss model */
923 nla_nest_cancel(skb, nest);
924 return 0; /* no data */
925
926 case CLG_4_STATES: {
927 struct tc_netem_gimodel gi = {
928 .p13 = q->clg.a1,
929 .p31 = q->clg.a2,
930 .p32 = q->clg.a3,
931 .p14 = q->clg.a4,
932 .p23 = q->clg.a5,
933 };
934
935 if (nla_put(skb, NETEM_LOSS_GI, sizeof(gi), &gi))
936 goto nla_put_failure;
937 break;
938 }
939 case CLG_GILB_ELL: {
940 struct tc_netem_gemodel ge = {
941 .p = q->clg.a1,
942 .r = q->clg.a2,
943 .h = q->clg.a3,
944 .k1 = q->clg.a4,
945 };
946
947 if (nla_put(skb, NETEM_LOSS_GE, sizeof(ge), &ge))
948 goto nla_put_failure;
949 break;
950 }
951 }
952
953 nla_nest_end(skb, nest);
954 return 0;
955
956 nla_put_failure:
957 nla_nest_cancel(skb, nest);
958 return -1;
959 }
960
961 static int netem_dump(struct Qdisc *sch, struct sk_buff *skb)
962 {
963 const struct netem_sched_data *q = qdisc_priv(sch);
964 struct nlattr *nla = (struct nlattr *) skb_tail_pointer(skb);
965 struct tc_netem_qopt qopt;
966 struct tc_netem_corr cor;
967 struct tc_netem_reorder reorder;
968 struct tc_netem_corrupt corrupt;
969 struct tc_netem_rate rate;
970
971 qopt.latency = q->latency;
972 qopt.jitter = q->jitter;
973 qopt.limit = q->limit;
974 qopt.loss = q->loss;
975 qopt.gap = q->gap;
976 qopt.duplicate = q->duplicate;
977 if (nla_put(skb, TCA_OPTIONS, sizeof(qopt), &qopt))
978 goto nla_put_failure;
979
980 cor.delay_corr = q->delay_cor.rho;
981 cor.loss_corr = q->loss_cor.rho;
982 cor.dup_corr = q->dup_cor.rho;
983 if (nla_put(skb, TCA_NETEM_CORR, sizeof(cor), &cor))
984 goto nla_put_failure;
985
986 reorder.probability = q->reorder;
987 reorder.correlation = q->reorder_cor.rho;
988 if (nla_put(skb, TCA_NETEM_REORDER, sizeof(reorder), &reorder))
989 goto nla_put_failure;
990
991 corrupt.probability = q->corrupt;
992 corrupt.correlation = q->corrupt_cor.rho;
993 if (nla_put(skb, TCA_NETEM_CORRUPT, sizeof(corrupt), &corrupt))
994 goto nla_put_failure;
995
996 if (q->rate >= (1ULL << 32)) {
997 if (nla_put_u64(skb, TCA_NETEM_RATE64, q->rate))
998 goto nla_put_failure;
999 rate.rate = ~0U;
1000 } else {
1001 rate.rate = q->rate;
1002 }
1003 rate.packet_overhead = q->packet_overhead;
1004 rate.cell_size = q->cell_size;
1005 rate.cell_overhead = q->cell_overhead;
1006 if (nla_put(skb, TCA_NETEM_RATE, sizeof(rate), &rate))
1007 goto nla_put_failure;
1008
1009 if (q->ecn && nla_put_u32(skb, TCA_NETEM_ECN, q->ecn))
1010 goto nla_put_failure;
1011
1012 if (dump_loss_model(q, skb) != 0)
1013 goto nla_put_failure;
1014
1015 return nla_nest_end(skb, nla);
1016
1017 nla_put_failure:
1018 nlmsg_trim(skb, nla);
1019 return -1;
1020 }
1021
1022 static int netem_dump_class(struct Qdisc *sch, unsigned long cl,
1023 struct sk_buff *skb, struct tcmsg *tcm)
1024 {
1025 struct netem_sched_data *q = qdisc_priv(sch);
1026
1027 if (cl != 1 || !q->qdisc) /* only one class */
1028 return -ENOENT;
1029
1030 tcm->tcm_handle |= TC_H_MIN(1);
1031 tcm->tcm_info = q->qdisc->handle;
1032
1033 return 0;
1034 }
1035
1036 static int netem_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
1037 struct Qdisc **old)
1038 {
1039 struct netem_sched_data *q = qdisc_priv(sch);
1040
1041 *old = qdisc_replace(sch, new, &q->qdisc);
1042 return 0;
1043 }
1044
1045 static struct Qdisc *netem_leaf(struct Qdisc *sch, unsigned long arg)
1046 {
1047 struct netem_sched_data *q = qdisc_priv(sch);
1048 return q->qdisc;
1049 }
1050
1051 static unsigned long netem_get(struct Qdisc *sch, u32 classid)
1052 {
1053 return 1;
1054 }
1055
1056 static void netem_put(struct Qdisc *sch, unsigned long arg)
1057 {
1058 }
1059
1060 static void netem_walk(struct Qdisc *sch, struct qdisc_walker *walker)
1061 {
1062 if (!walker->stop) {
1063 if (walker->count >= walker->skip)
1064 if (walker->fn(sch, 1, walker) < 0) {
1065 walker->stop = 1;
1066 return;
1067 }
1068 walker->count++;
1069 }
1070 }
1071
1072 static const struct Qdisc_class_ops netem_class_ops = {
1073 .graft = netem_graft,
1074 .leaf = netem_leaf,
1075 .get = netem_get,
1076 .put = netem_put,
1077 .walk = netem_walk,
1078 .dump = netem_dump_class,
1079 };
1080
1081 static struct Qdisc_ops netem_qdisc_ops __read_mostly = {
1082 .id = "netem",
1083 .cl_ops = &netem_class_ops,
1084 .priv_size = sizeof(struct netem_sched_data),
1085 .enqueue = netem_enqueue,
1086 .dequeue = netem_dequeue,
1087 .peek = qdisc_peek_dequeued,
1088 .drop = netem_drop,
1089 .init = netem_init,
1090 .reset = netem_reset,
1091 .destroy = netem_destroy,
1092 .change = netem_change,
1093 .dump = netem_dump,
1094 .owner = THIS_MODULE,
1095 };
1096
1097
1098 static int __init netem_module_init(void)
1099 {
1100 pr_info("netem: version " VERSION "\n");
1101 return register_qdisc(&netem_qdisc_ops);
1102 }
1103 static void __exit netem_module_exit(void)
1104 {
1105 unregister_qdisc(&netem_qdisc_ops);
1106 }
1107 module_init(netem_module_init)
1108 module_exit(netem_module_exit)
1109 MODULE_LICENSE("GPL");
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