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Merge branches 'regmap-linus' and 'regmap-interface' into regmap-next
[deliverable/linux.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
26 #include <net/netlink.h>
27 #include <net/pkt_sched.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 netem_sched_data {
69 struct Qdisc *qdisc;
70 struct qdisc_watchdog watchdog;
71
72 psched_tdiff_t latency;
73 psched_tdiff_t jitter;
74
75 u32 loss;
76 u32 limit;
77 u32 counter;
78 u32 gap;
79 u32 duplicate;
80 u32 reorder;
81 u32 corrupt;
82
83 struct crndstate {
84 u32 last;
85 u32 rho;
86 } delay_cor, loss_cor, dup_cor, reorder_cor, corrupt_cor;
87
88 struct disttable {
89 u32 size;
90 s16 table[0];
91 } *delay_dist;
92
93 enum {
94 CLG_RANDOM,
95 CLG_4_STATES,
96 CLG_GILB_ELL,
97 } loss_model;
98
99 /* Correlated Loss Generation models */
100 struct clgstate {
101 /* state of the Markov chain */
102 u8 state;
103
104 /* 4-states and Gilbert-Elliot models */
105 u32 a1; /* p13 for 4-states or p for GE */
106 u32 a2; /* p31 for 4-states or r for GE */
107 u32 a3; /* p32 for 4-states or h for GE */
108 u32 a4; /* p14 for 4-states or 1-k for GE */
109 u32 a5; /* p23 used only in 4-states */
110 } clg;
111
112 };
113
114 /* Time stamp put into socket buffer control block */
115 struct netem_skb_cb {
116 psched_time_t time_to_send;
117 };
118
119 static inline struct netem_skb_cb *netem_skb_cb(struct sk_buff *skb)
120 {
121 BUILD_BUG_ON(sizeof(skb->cb) <
122 sizeof(struct qdisc_skb_cb) + sizeof(struct netem_skb_cb));
123 return (struct netem_skb_cb *)qdisc_skb_cb(skb)->data;
124 }
125
126 /* init_crandom - initialize correlated random number generator
127 * Use entropy source for initial seed.
128 */
129 static void init_crandom(struct crndstate *state, unsigned long rho)
130 {
131 state->rho = rho;
132 state->last = net_random();
133 }
134
135 /* get_crandom - correlated random number generator
136 * Next number depends on last value.
137 * rho is scaled to avoid floating point.
138 */
139 static u32 get_crandom(struct crndstate *state)
140 {
141 u64 value, rho;
142 unsigned long answer;
143
144 if (state->rho == 0) /* no correlation */
145 return net_random();
146
147 value = net_random();
148 rho = (u64)state->rho + 1;
149 answer = (value * ((1ull<<32) - rho) + state->last * rho) >> 32;
150 state->last = answer;
151 return answer;
152 }
153
154 /* loss_4state - 4-state model loss generator
155 * Generates losses according to the 4-state Markov chain adopted in
156 * the GI (General and Intuitive) loss model.
157 */
158 static bool loss_4state(struct netem_sched_data *q)
159 {
160 struct clgstate *clg = &q->clg;
161 u32 rnd = net_random();
162
163 /*
164 * Makes a comparison between rnd and the transition
165 * probabilities outgoing from the current state, then decides the
166 * next state and if the next packet has to be transmitted or lost.
167 * The four states correspond to:
168 * 1 => successfully transmitted packets within a gap period
169 * 4 => isolated losses within a gap period
170 * 3 => lost packets within a burst period
171 * 2 => successfully transmitted packets within a burst period
172 */
173 switch (clg->state) {
174 case 1:
175 if (rnd < clg->a4) {
176 clg->state = 4;
177 return true;
178 } else if (clg->a4 < rnd && rnd < clg->a1) {
179 clg->state = 3;
180 return true;
181 } else if (clg->a1 < rnd)
182 clg->state = 1;
183
184 break;
185 case 2:
186 if (rnd < clg->a5) {
187 clg->state = 3;
188 return true;
189 } else
190 clg->state = 2;
191
192 break;
193 case 3:
194 if (rnd < clg->a3)
195 clg->state = 2;
196 else if (clg->a3 < rnd && rnd < clg->a2 + clg->a3) {
197 clg->state = 1;
198 return true;
199 } else if (clg->a2 + clg->a3 < rnd) {
200 clg->state = 3;
201 return true;
202 }
203 break;
204 case 4:
205 clg->state = 1;
206 break;
207 }
208
209 return false;
210 }
211
212 /* loss_gilb_ell - Gilbert-Elliot model loss generator
213 * Generates losses according to the Gilbert-Elliot loss model or
214 * its special cases (Gilbert or Simple Gilbert)
215 *
216 * Makes a comparison between random number and the transition
217 * probabilities outgoing from the current state, then decides the
218 * next state. A second random number is extracted and the comparison
219 * with the loss probability of the current state decides if the next
220 * packet will be transmitted or lost.
221 */
222 static bool loss_gilb_ell(struct netem_sched_data *q)
223 {
224 struct clgstate *clg = &q->clg;
225
226 switch (clg->state) {
227 case 1:
228 if (net_random() < clg->a1)
229 clg->state = 2;
230 if (net_random() < clg->a4)
231 return true;
232 case 2:
233 if (net_random() < clg->a2)
234 clg->state = 1;
235 if (clg->a3 > net_random())
236 return true;
237 }
238
239 return false;
240 }
241
242 static bool loss_event(struct netem_sched_data *q)
243 {
244 switch (q->loss_model) {
245 case CLG_RANDOM:
246 /* Random packet drop 0 => none, ~0 => all */
247 return q->loss && q->loss >= get_crandom(&q->loss_cor);
248
249 case CLG_4_STATES:
250 /* 4state loss model algorithm (used also for GI model)
251 * Extracts a value from the markov 4 state loss generator,
252 * if it is 1 drops a packet and if needed writes the event in
253 * the kernel logs
254 */
255 return loss_4state(q);
256
257 case CLG_GILB_ELL:
258 /* Gilbert-Elliot loss model algorithm
259 * Extracts a value from the Gilbert-Elliot loss generator,
260 * if it is 1 drops a packet and if needed writes the event in
261 * the kernel logs
262 */
263 return loss_gilb_ell(q);
264 }
265
266 return false; /* not reached */
267 }
268
269
270 /* tabledist - return a pseudo-randomly distributed value with mean mu and
271 * std deviation sigma. Uses table lookup to approximate the desired
272 * distribution, and a uniformly-distributed pseudo-random source.
273 */
274 static psched_tdiff_t tabledist(psched_tdiff_t mu, psched_tdiff_t sigma,
275 struct crndstate *state,
276 const struct disttable *dist)
277 {
278 psched_tdiff_t x;
279 long t;
280 u32 rnd;
281
282 if (sigma == 0)
283 return mu;
284
285 rnd = get_crandom(state);
286
287 /* default uniform distribution */
288 if (dist == NULL)
289 return (rnd % (2*sigma)) - sigma + mu;
290
291 t = dist->table[rnd % dist->size];
292 x = (sigma % NETEM_DIST_SCALE) * t;
293 if (x >= 0)
294 x += NETEM_DIST_SCALE/2;
295 else
296 x -= NETEM_DIST_SCALE/2;
297
298 return x / NETEM_DIST_SCALE + (sigma / NETEM_DIST_SCALE) * t + mu;
299 }
300
301 /*
302 * Insert one skb into qdisc.
303 * Note: parent depends on return value to account for queue length.
304 * NET_XMIT_DROP: queue length didn't change.
305 * NET_XMIT_SUCCESS: one skb was queued.
306 */
307 static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch)
308 {
309 struct netem_sched_data *q = qdisc_priv(sch);
310 /* We don't fill cb now as skb_unshare() may invalidate it */
311 struct netem_skb_cb *cb;
312 struct sk_buff *skb2;
313 int ret;
314 int count = 1;
315
316 /* Random duplication */
317 if (q->duplicate && q->duplicate >= get_crandom(&q->dup_cor))
318 ++count;
319
320 /* Drop packet? */
321 if (loss_event(q))
322 --count;
323
324 if (count == 0) {
325 sch->qstats.drops++;
326 kfree_skb(skb);
327 return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
328 }
329
330 skb_orphan(skb);
331
332 /*
333 * If we need to duplicate packet, then re-insert at top of the
334 * qdisc tree, since parent queuer expects that only one
335 * skb will be queued.
336 */
337 if (count > 1 && (skb2 = skb_clone(skb, GFP_ATOMIC)) != NULL) {
338 struct Qdisc *rootq = qdisc_root(sch);
339 u32 dupsave = q->duplicate; /* prevent duplicating a dup... */
340 q->duplicate = 0;
341
342 qdisc_enqueue_root(skb2, rootq);
343 q->duplicate = dupsave;
344 }
345
346 /*
347 * Randomized packet corruption.
348 * Make copy if needed since we are modifying
349 * If packet is going to be hardware checksummed, then
350 * do it now in software before we mangle it.
351 */
352 if (q->corrupt && q->corrupt >= get_crandom(&q->corrupt_cor)) {
353 if (!(skb = skb_unshare(skb, GFP_ATOMIC)) ||
354 (skb->ip_summed == CHECKSUM_PARTIAL &&
355 skb_checksum_help(skb))) {
356 sch->qstats.drops++;
357 return NET_XMIT_DROP;
358 }
359
360 skb->data[net_random() % skb_headlen(skb)] ^= 1<<(net_random() % 8);
361 }
362
363 cb = netem_skb_cb(skb);
364 if (q->gap == 0 || /* not doing reordering */
365 q->counter < q->gap || /* inside last reordering gap */
366 q->reorder < get_crandom(&q->reorder_cor)) {
367 psched_time_t now;
368 psched_tdiff_t delay;
369
370 delay = tabledist(q->latency, q->jitter,
371 &q->delay_cor, q->delay_dist);
372
373 now = psched_get_time();
374 cb->time_to_send = now + delay;
375 ++q->counter;
376 ret = qdisc_enqueue(skb, q->qdisc);
377 } else {
378 /*
379 * Do re-ordering by putting one out of N packets at the front
380 * of the queue.
381 */
382 cb->time_to_send = psched_get_time();
383 q->counter = 0;
384
385 __skb_queue_head(&q->qdisc->q, skb);
386 q->qdisc->qstats.backlog += qdisc_pkt_len(skb);
387 q->qdisc->qstats.requeues++;
388 ret = NET_XMIT_SUCCESS;
389 }
390
391 if (ret != NET_XMIT_SUCCESS) {
392 if (net_xmit_drop_count(ret)) {
393 sch->qstats.drops++;
394 return ret;
395 }
396 }
397
398 sch->q.qlen++;
399 return NET_XMIT_SUCCESS;
400 }
401
402 static unsigned int netem_drop(struct Qdisc *sch)
403 {
404 struct netem_sched_data *q = qdisc_priv(sch);
405 unsigned int len = 0;
406
407 if (q->qdisc->ops->drop && (len = q->qdisc->ops->drop(q->qdisc)) != 0) {
408 sch->q.qlen--;
409 sch->qstats.drops++;
410 }
411 return len;
412 }
413
414 static struct sk_buff *netem_dequeue(struct Qdisc *sch)
415 {
416 struct netem_sched_data *q = qdisc_priv(sch);
417 struct sk_buff *skb;
418
419 if (qdisc_is_throttled(sch))
420 return NULL;
421
422 skb = q->qdisc->ops->peek(q->qdisc);
423 if (skb) {
424 const struct netem_skb_cb *cb = netem_skb_cb(skb);
425 psched_time_t now = psched_get_time();
426
427 /* if more time remaining? */
428 if (cb->time_to_send <= now) {
429 skb = qdisc_dequeue_peeked(q->qdisc);
430 if (unlikely(!skb))
431 return NULL;
432
433 #ifdef CONFIG_NET_CLS_ACT
434 /*
435 * If it's at ingress let's pretend the delay is
436 * from the network (tstamp will be updated).
437 */
438 if (G_TC_FROM(skb->tc_verd) & AT_INGRESS)
439 skb->tstamp.tv64 = 0;
440 #endif
441
442 sch->q.qlen--;
443 qdisc_unthrottled(sch);
444 qdisc_bstats_update(sch, skb);
445 return skb;
446 }
447
448 qdisc_watchdog_schedule(&q->watchdog, cb->time_to_send);
449 }
450
451 return NULL;
452 }
453
454 static void netem_reset(struct Qdisc *sch)
455 {
456 struct netem_sched_data *q = qdisc_priv(sch);
457
458 qdisc_reset(q->qdisc);
459 sch->q.qlen = 0;
460 qdisc_watchdog_cancel(&q->watchdog);
461 }
462
463 static void dist_free(struct disttable *d)
464 {
465 if (d) {
466 if (is_vmalloc_addr(d))
467 vfree(d);
468 else
469 kfree(d);
470 }
471 }
472
473 /*
474 * Distribution data is a variable size payload containing
475 * signed 16 bit values.
476 */
477 static int get_dist_table(struct Qdisc *sch, const struct nlattr *attr)
478 {
479 struct netem_sched_data *q = qdisc_priv(sch);
480 size_t n = nla_len(attr)/sizeof(__s16);
481 const __s16 *data = nla_data(attr);
482 spinlock_t *root_lock;
483 struct disttable *d;
484 int i;
485 size_t s;
486
487 if (n > NETEM_DIST_MAX)
488 return -EINVAL;
489
490 s = sizeof(struct disttable) + n * sizeof(s16);
491 d = kmalloc(s, GFP_KERNEL);
492 if (!d)
493 d = vmalloc(s);
494 if (!d)
495 return -ENOMEM;
496
497 d->size = n;
498 for (i = 0; i < n; i++)
499 d->table[i] = data[i];
500
501 root_lock = qdisc_root_sleeping_lock(sch);
502
503 spin_lock_bh(root_lock);
504 dist_free(q->delay_dist);
505 q->delay_dist = d;
506 spin_unlock_bh(root_lock);
507 return 0;
508 }
509
510 static void get_correlation(struct Qdisc *sch, const struct nlattr *attr)
511 {
512 struct netem_sched_data *q = qdisc_priv(sch);
513 const struct tc_netem_corr *c = nla_data(attr);
514
515 init_crandom(&q->delay_cor, c->delay_corr);
516 init_crandom(&q->loss_cor, c->loss_corr);
517 init_crandom(&q->dup_cor, c->dup_corr);
518 }
519
520 static void get_reorder(struct Qdisc *sch, const struct nlattr *attr)
521 {
522 struct netem_sched_data *q = qdisc_priv(sch);
523 const struct tc_netem_reorder *r = nla_data(attr);
524
525 q->reorder = r->probability;
526 init_crandom(&q->reorder_cor, r->correlation);
527 }
528
529 static void get_corrupt(struct Qdisc *sch, const struct nlattr *attr)
530 {
531 struct netem_sched_data *q = qdisc_priv(sch);
532 const struct tc_netem_corrupt *r = nla_data(attr);
533
534 q->corrupt = r->probability;
535 init_crandom(&q->corrupt_cor, r->correlation);
536 }
537
538 static int get_loss_clg(struct Qdisc *sch, const struct nlattr *attr)
539 {
540 struct netem_sched_data *q = qdisc_priv(sch);
541 const struct nlattr *la;
542 int rem;
543
544 nla_for_each_nested(la, attr, rem) {
545 u16 type = nla_type(la);
546
547 switch(type) {
548 case NETEM_LOSS_GI: {
549 const struct tc_netem_gimodel *gi = nla_data(la);
550
551 if (nla_len(la) != sizeof(struct tc_netem_gimodel)) {
552 pr_info("netem: incorrect gi model size\n");
553 return -EINVAL;
554 }
555
556 q->loss_model = CLG_4_STATES;
557
558 q->clg.state = 1;
559 q->clg.a1 = gi->p13;
560 q->clg.a2 = gi->p31;
561 q->clg.a3 = gi->p32;
562 q->clg.a4 = gi->p14;
563 q->clg.a5 = gi->p23;
564 break;
565 }
566
567 case NETEM_LOSS_GE: {
568 const struct tc_netem_gemodel *ge = nla_data(la);
569
570 if (nla_len(la) != sizeof(struct tc_netem_gemodel)) {
571 pr_info("netem: incorrect gi model size\n");
572 return -EINVAL;
573 }
574
575 q->loss_model = CLG_GILB_ELL;
576 q->clg.state = 1;
577 q->clg.a1 = ge->p;
578 q->clg.a2 = ge->r;
579 q->clg.a3 = ge->h;
580 q->clg.a4 = ge->k1;
581 break;
582 }
583
584 default:
585 pr_info("netem: unknown loss type %u\n", type);
586 return -EINVAL;
587 }
588 }
589
590 return 0;
591 }
592
593 static const struct nla_policy netem_policy[TCA_NETEM_MAX + 1] = {
594 [TCA_NETEM_CORR] = { .len = sizeof(struct tc_netem_corr) },
595 [TCA_NETEM_REORDER] = { .len = sizeof(struct tc_netem_reorder) },
596 [TCA_NETEM_CORRUPT] = { .len = sizeof(struct tc_netem_corrupt) },
597 [TCA_NETEM_LOSS] = { .type = NLA_NESTED },
598 };
599
600 static int parse_attr(struct nlattr *tb[], int maxtype, struct nlattr *nla,
601 const struct nla_policy *policy, int len)
602 {
603 int nested_len = nla_len(nla) - NLA_ALIGN(len);
604
605 if (nested_len < 0) {
606 pr_info("netem: invalid attributes len %d\n", nested_len);
607 return -EINVAL;
608 }
609
610 if (nested_len >= nla_attr_size(0))
611 return nla_parse(tb, maxtype, nla_data(nla) + NLA_ALIGN(len),
612 nested_len, policy);
613
614 memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
615 return 0;
616 }
617
618 /* Parse netlink message to set options */
619 static int netem_change(struct Qdisc *sch, struct nlattr *opt)
620 {
621 struct netem_sched_data *q = qdisc_priv(sch);
622 struct nlattr *tb[TCA_NETEM_MAX + 1];
623 struct tc_netem_qopt *qopt;
624 int ret;
625
626 if (opt == NULL)
627 return -EINVAL;
628
629 qopt = nla_data(opt);
630 ret = parse_attr(tb, TCA_NETEM_MAX, opt, netem_policy, sizeof(*qopt));
631 if (ret < 0)
632 return ret;
633
634 ret = fifo_set_limit(q->qdisc, qopt->limit);
635 if (ret) {
636 pr_info("netem: can't set fifo limit\n");
637 return ret;
638 }
639
640 q->latency = qopt->latency;
641 q->jitter = qopt->jitter;
642 q->limit = qopt->limit;
643 q->gap = qopt->gap;
644 q->counter = 0;
645 q->loss = qopt->loss;
646 q->duplicate = qopt->duplicate;
647
648 /* for compatibility with earlier versions.
649 * if gap is set, need to assume 100% probability
650 */
651 if (q->gap)
652 q->reorder = ~0;
653
654 if (tb[TCA_NETEM_CORR])
655 get_correlation(sch, tb[TCA_NETEM_CORR]);
656
657 if (tb[TCA_NETEM_DELAY_DIST]) {
658 ret = get_dist_table(sch, tb[TCA_NETEM_DELAY_DIST]);
659 if (ret)
660 return ret;
661 }
662
663 if (tb[TCA_NETEM_REORDER])
664 get_reorder(sch, tb[TCA_NETEM_REORDER]);
665
666 if (tb[TCA_NETEM_CORRUPT])
667 get_corrupt(sch, tb[TCA_NETEM_CORRUPT]);
668
669 q->loss_model = CLG_RANDOM;
670 if (tb[TCA_NETEM_LOSS])
671 ret = get_loss_clg(sch, tb[TCA_NETEM_LOSS]);
672
673 return ret;
674 }
675
676 /*
677 * Special case version of FIFO queue for use by netem.
678 * It queues in order based on timestamps in skb's
679 */
680 struct fifo_sched_data {
681 u32 limit;
682 psched_time_t oldest;
683 };
684
685 static int tfifo_enqueue(struct sk_buff *nskb, struct Qdisc *sch)
686 {
687 struct fifo_sched_data *q = qdisc_priv(sch);
688 struct sk_buff_head *list = &sch->q;
689 psched_time_t tnext = netem_skb_cb(nskb)->time_to_send;
690 struct sk_buff *skb;
691
692 if (likely(skb_queue_len(list) < q->limit)) {
693 /* Optimize for add at tail */
694 if (likely(skb_queue_empty(list) || tnext >= q->oldest)) {
695 q->oldest = tnext;
696 return qdisc_enqueue_tail(nskb, sch);
697 }
698
699 skb_queue_reverse_walk(list, skb) {
700 const struct netem_skb_cb *cb = netem_skb_cb(skb);
701
702 if (tnext >= cb->time_to_send)
703 break;
704 }
705
706 __skb_queue_after(list, skb, nskb);
707
708 sch->qstats.backlog += qdisc_pkt_len(nskb);
709
710 return NET_XMIT_SUCCESS;
711 }
712
713 return qdisc_reshape_fail(nskb, sch);
714 }
715
716 static int tfifo_init(struct Qdisc *sch, struct nlattr *opt)
717 {
718 struct fifo_sched_data *q = qdisc_priv(sch);
719
720 if (opt) {
721 struct tc_fifo_qopt *ctl = nla_data(opt);
722 if (nla_len(opt) < sizeof(*ctl))
723 return -EINVAL;
724
725 q->limit = ctl->limit;
726 } else
727 q->limit = max_t(u32, qdisc_dev(sch)->tx_queue_len, 1);
728
729 q->oldest = PSCHED_PASTPERFECT;
730 return 0;
731 }
732
733 static int tfifo_dump(struct Qdisc *sch, struct sk_buff *skb)
734 {
735 struct fifo_sched_data *q = qdisc_priv(sch);
736 struct tc_fifo_qopt opt = { .limit = q->limit };
737
738 NLA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
739 return skb->len;
740
741 nla_put_failure:
742 return -1;
743 }
744
745 static struct Qdisc_ops tfifo_qdisc_ops __read_mostly = {
746 .id = "tfifo",
747 .priv_size = sizeof(struct fifo_sched_data),
748 .enqueue = tfifo_enqueue,
749 .dequeue = qdisc_dequeue_head,
750 .peek = qdisc_peek_head,
751 .drop = qdisc_queue_drop,
752 .init = tfifo_init,
753 .reset = qdisc_reset_queue,
754 .change = tfifo_init,
755 .dump = tfifo_dump,
756 };
757
758 static int netem_init(struct Qdisc *sch, struct nlattr *opt)
759 {
760 struct netem_sched_data *q = qdisc_priv(sch);
761 int ret;
762
763 if (!opt)
764 return -EINVAL;
765
766 qdisc_watchdog_init(&q->watchdog, sch);
767
768 q->loss_model = CLG_RANDOM;
769 q->qdisc = qdisc_create_dflt(sch->dev_queue, &tfifo_qdisc_ops,
770 TC_H_MAKE(sch->handle, 1));
771 if (!q->qdisc) {
772 pr_notice("netem: qdisc create tfifo qdisc failed\n");
773 return -ENOMEM;
774 }
775
776 ret = netem_change(sch, opt);
777 if (ret) {
778 pr_info("netem: change failed\n");
779 qdisc_destroy(q->qdisc);
780 }
781 return ret;
782 }
783
784 static void netem_destroy(struct Qdisc *sch)
785 {
786 struct netem_sched_data *q = qdisc_priv(sch);
787
788 qdisc_watchdog_cancel(&q->watchdog);
789 qdisc_destroy(q->qdisc);
790 dist_free(q->delay_dist);
791 }
792
793 static int dump_loss_model(const struct netem_sched_data *q,
794 struct sk_buff *skb)
795 {
796 struct nlattr *nest;
797
798 nest = nla_nest_start(skb, TCA_NETEM_LOSS);
799 if (nest == NULL)
800 goto nla_put_failure;
801
802 switch (q->loss_model) {
803 case CLG_RANDOM:
804 /* legacy loss model */
805 nla_nest_cancel(skb, nest);
806 return 0; /* no data */
807
808 case CLG_4_STATES: {
809 struct tc_netem_gimodel gi = {
810 .p13 = q->clg.a1,
811 .p31 = q->clg.a2,
812 .p32 = q->clg.a3,
813 .p14 = q->clg.a4,
814 .p23 = q->clg.a5,
815 };
816
817 NLA_PUT(skb, NETEM_LOSS_GI, sizeof(gi), &gi);
818 break;
819 }
820 case CLG_GILB_ELL: {
821 struct tc_netem_gemodel ge = {
822 .p = q->clg.a1,
823 .r = q->clg.a2,
824 .h = q->clg.a3,
825 .k1 = q->clg.a4,
826 };
827
828 NLA_PUT(skb, NETEM_LOSS_GE, sizeof(ge), &ge);
829 break;
830 }
831 }
832
833 nla_nest_end(skb, nest);
834 return 0;
835
836 nla_put_failure:
837 nla_nest_cancel(skb, nest);
838 return -1;
839 }
840
841 static int netem_dump(struct Qdisc *sch, struct sk_buff *skb)
842 {
843 const struct netem_sched_data *q = qdisc_priv(sch);
844 struct nlattr *nla = (struct nlattr *) skb_tail_pointer(skb);
845 struct tc_netem_qopt qopt;
846 struct tc_netem_corr cor;
847 struct tc_netem_reorder reorder;
848 struct tc_netem_corrupt corrupt;
849
850 qopt.latency = q->latency;
851 qopt.jitter = q->jitter;
852 qopt.limit = q->limit;
853 qopt.loss = q->loss;
854 qopt.gap = q->gap;
855 qopt.duplicate = q->duplicate;
856 NLA_PUT(skb, TCA_OPTIONS, sizeof(qopt), &qopt);
857
858 cor.delay_corr = q->delay_cor.rho;
859 cor.loss_corr = q->loss_cor.rho;
860 cor.dup_corr = q->dup_cor.rho;
861 NLA_PUT(skb, TCA_NETEM_CORR, sizeof(cor), &cor);
862
863 reorder.probability = q->reorder;
864 reorder.correlation = q->reorder_cor.rho;
865 NLA_PUT(skb, TCA_NETEM_REORDER, sizeof(reorder), &reorder);
866
867 corrupt.probability = q->corrupt;
868 corrupt.correlation = q->corrupt_cor.rho;
869 NLA_PUT(skb, TCA_NETEM_CORRUPT, sizeof(corrupt), &corrupt);
870
871 if (dump_loss_model(q, skb) != 0)
872 goto nla_put_failure;
873
874 return nla_nest_end(skb, nla);
875
876 nla_put_failure:
877 nlmsg_trim(skb, nla);
878 return -1;
879 }
880
881 static int netem_dump_class(struct Qdisc *sch, unsigned long cl,
882 struct sk_buff *skb, struct tcmsg *tcm)
883 {
884 struct netem_sched_data *q = qdisc_priv(sch);
885
886 if (cl != 1) /* only one class */
887 return -ENOENT;
888
889 tcm->tcm_handle |= TC_H_MIN(1);
890 tcm->tcm_info = q->qdisc->handle;
891
892 return 0;
893 }
894
895 static int netem_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
896 struct Qdisc **old)
897 {
898 struct netem_sched_data *q = qdisc_priv(sch);
899
900 if (new == NULL)
901 new = &noop_qdisc;
902
903 sch_tree_lock(sch);
904 *old = q->qdisc;
905 q->qdisc = new;
906 qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
907 qdisc_reset(*old);
908 sch_tree_unlock(sch);
909
910 return 0;
911 }
912
913 static struct Qdisc *netem_leaf(struct Qdisc *sch, unsigned long arg)
914 {
915 struct netem_sched_data *q = qdisc_priv(sch);
916 return q->qdisc;
917 }
918
919 static unsigned long netem_get(struct Qdisc *sch, u32 classid)
920 {
921 return 1;
922 }
923
924 static void netem_put(struct Qdisc *sch, unsigned long arg)
925 {
926 }
927
928 static void netem_walk(struct Qdisc *sch, struct qdisc_walker *walker)
929 {
930 if (!walker->stop) {
931 if (walker->count >= walker->skip)
932 if (walker->fn(sch, 1, walker) < 0) {
933 walker->stop = 1;
934 return;
935 }
936 walker->count++;
937 }
938 }
939
940 static const struct Qdisc_class_ops netem_class_ops = {
941 .graft = netem_graft,
942 .leaf = netem_leaf,
943 .get = netem_get,
944 .put = netem_put,
945 .walk = netem_walk,
946 .dump = netem_dump_class,
947 };
948
949 static struct Qdisc_ops netem_qdisc_ops __read_mostly = {
950 .id = "netem",
951 .cl_ops = &netem_class_ops,
952 .priv_size = sizeof(struct netem_sched_data),
953 .enqueue = netem_enqueue,
954 .dequeue = netem_dequeue,
955 .peek = qdisc_peek_dequeued,
956 .drop = netem_drop,
957 .init = netem_init,
958 .reset = netem_reset,
959 .destroy = netem_destroy,
960 .change = netem_change,
961 .dump = netem_dump,
962 .owner = THIS_MODULE,
963 };
964
965
966 static int __init netem_module_init(void)
967 {
968 pr_info("netem: version " VERSION "\n");
969 return register_qdisc(&netem_qdisc_ops);
970 }
971 static void __exit netem_module_exit(void)
972 {
973 unregister_qdisc(&netem_qdisc_ops);
974 }
975 module_init(netem_module_init)
976 module_exit(netem_module_exit)
977 MODULE_LICENSE("GPL");
Linux kernel - Deliverables
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