2 * net/sched/sch_netem.c Network emulator
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
9 * Many of the algorithms and ideas for this came from
10 * NIST Net which is not copyrighted.
12 * Authors: Stephen Hemminger <shemminger@osdl.org>
13 * Catalin(ux aka Dino) BOIE <catab at umbrella dot ro>
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>
28 #include <net/netlink.h>
29 #include <net/pkt_sched.h>
30 #include <net/inet_ecn.h>
34 /* Network Emulation Queuing algorithm.
35 ====================================
37 Sources: [1] Mark Carson, Darrin Santay, "NIST Net - A Linux-based
38 Network Emulation Tool
39 [2] Luigi Rizzo, DummyNet for FreeBSD
41 ----------------------------------------------------------------
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.
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.
56 Correlated Loss Generator models
58 Added generation of correlated loss according to the
59 "Gilbert-Elliot" model, a 4-state markov model.
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]
67 Authors: Stefano Salsano <stefano.salsano at uniroma2.it
68 Fabio Ludovici <fabio.ludovici at yahoo.it>
76 struct netem_sched_data {
77 /* internal t(ime)fifo qdisc uses t_root and sch->limit */
78 struct rb_root t_root;
80 /* optional qdisc for classful handling (NULL at netem init) */
83 struct qdisc_watchdog watchdog;
99 struct reciprocal_value cell_size_reciprocal;
105 } delay_cor, loss_cor, dup_cor, reorder_cor, corrupt_cor;
107 struct disttable *delay_dist;
116 TX_IN_GAP_PERIOD = 1,
119 LOST_IN_BURST_PERIOD,
127 /* Correlated Loss Generation models */
129 /* state of the Markov chain */
132 /* 4-states and Gilbert-Elliot models */
133 u32 a1; /* p13 for 4-states or p for GE */
134 u32 a2; /* p31 for 4-states or r for GE */
135 u32 a3; /* p32 for 4-states or h for GE */
136 u32 a4; /* p14 for 4-states or 1-k for GE */
137 u32 a5; /* p23 used only in 4-states */
140 struct tc_netem_slot slot_config;
147 struct disttable *slot_dist;
150 /* Time stamp put into socket buffer control block
151 * Only valid when skbs are in our internal t(ime)fifo queue.
153 * As skb->rbnode uses same storage than skb->next, skb->prev and skb->tstamp,
154 * and skb->next & skb->prev are scratch space for a qdisc,
155 * we save skb->tstamp value in skb->cb[] before destroying it.
157 struct netem_skb_cb {
161 static inline struct netem_skb_cb *netem_skb_cb(struct sk_buff *skb)
163 /* we assume we can use skb next/prev/tstamp as storage for rb_node */
164 qdisc_cb_private_validate(skb, sizeof(struct netem_skb_cb));
165 return (struct netem_skb_cb *)qdisc_skb_cb(skb)->data;
168 /* init_crandom - initialize correlated random number generator
169 * Use entropy source for initial seed.
171 static void init_crandom(struct crndstate *state, unsigned long rho)
174 state->last = prandom_u32();
177 /* get_crandom - correlated random number generator
178 * Next number depends on last value.
179 * rho is scaled to avoid floating point.
181 static u32 get_crandom(struct crndstate *state)
184 unsigned long answer;
186 if (!state || state->rho == 0) /* no correlation */
187 return prandom_u32();
189 value = prandom_u32();
190 rho = (u64)state->rho + 1;
191 answer = (value * ((1ull<<32) - rho) + state->last * rho) >> 32;
192 state->last = answer;
196 /* loss_4state - 4-state model loss generator
197 * Generates losses according to the 4-state Markov chain adopted in
198 * the GI (General and Intuitive) loss model.
200 static bool loss_4state(struct netem_sched_data *q)
202 struct clgstate *clg = &q->clg;
203 u32 rnd = prandom_u32();
206 * Makes a comparison between rnd and the transition
207 * probabilities outgoing from the current state, then decides the
208 * next state and if the next packet has to be transmitted or lost.
209 * The four states correspond to:
210 * TX_IN_GAP_PERIOD => successfully transmitted packets within a gap period
211 * LOST_IN_BURST_PERIOD => isolated losses within a gap period
212 * LOST_IN_GAP_PERIOD => lost packets within a burst period
213 * TX_IN_GAP_PERIOD => successfully transmitted packets within a burst period
215 switch (clg->state) {
216 case TX_IN_GAP_PERIOD:
218 clg->state = LOST_IN_BURST_PERIOD;
220 } else if (clg->a4 < rnd && rnd < clg->a1 + clg->a4) {
221 clg->state = LOST_IN_GAP_PERIOD;
223 } else if (clg->a1 + clg->a4 < rnd) {
224 clg->state = TX_IN_GAP_PERIOD;
228 case TX_IN_BURST_PERIOD:
230 clg->state = LOST_IN_GAP_PERIOD;
233 clg->state = TX_IN_BURST_PERIOD;
237 case LOST_IN_GAP_PERIOD:
239 clg->state = TX_IN_BURST_PERIOD;
240 else if (clg->a3 < rnd && rnd < clg->a2 + clg->a3) {
241 clg->state = TX_IN_GAP_PERIOD;
242 } else if (clg->a2 + clg->a3 < rnd) {
243 clg->state = LOST_IN_GAP_PERIOD;
247 case LOST_IN_BURST_PERIOD:
248 clg->state = TX_IN_GAP_PERIOD;
255 /* loss_gilb_ell - Gilbert-Elliot model loss generator
256 * Generates losses according to the Gilbert-Elliot loss model or
257 * its special cases (Gilbert or Simple Gilbert)
259 * Makes a comparison between random number and the transition
260 * probabilities outgoing from the current state, then decides the
261 * next state. A second random number is extracted and the comparison
262 * with the loss probability of the current state decides if the next
263 * packet will be transmitted or lost.
265 static bool loss_gilb_ell(struct netem_sched_data *q)
267 struct clgstate *clg = &q->clg;
269 switch (clg->state) {
271 if (prandom_u32() < clg->a1)
272 clg->state = BAD_STATE;
273 if (prandom_u32() < clg->a4)
277 if (prandom_u32() < clg->a2)
278 clg->state = GOOD_STATE;
279 if (prandom_u32() > clg->a3)
286 static bool loss_event(struct netem_sched_data *q)
288 switch (q->loss_model) {
290 /* Random packet drop 0 => none, ~0 => all */
291 return q->loss && q->loss >= get_crandom(&q->loss_cor);
294 /* 4state loss model algorithm (used also for GI model)
295 * Extracts a value from the markov 4 state loss generator,
296 * if it is 1 drops a packet and if needed writes the event in
299 return loss_4state(q);
302 /* Gilbert-Elliot loss model algorithm
303 * Extracts a value from the Gilbert-Elliot loss generator,
304 * if it is 1 drops a packet and if needed writes the event in
307 return loss_gilb_ell(q);
310 return false; /* not reached */
314 /* tabledist - return a pseudo-randomly distributed value with mean mu and
315 * std deviation sigma. Uses table lookup to approximate the desired
316 * distribution, and a uniformly-distributed pseudo-random source.
318 static s64 tabledist(s64 mu, s32 sigma,
319 struct crndstate *state,
320 const struct disttable *dist)
329 rnd = get_crandom(state);
331 /* default uniform distribution */
333 return ((rnd % (2 * sigma)) + mu) - sigma;
335 t = dist->table[rnd % dist->size];
336 x = (sigma % NETEM_DIST_SCALE) * t;
338 x += NETEM_DIST_SCALE/2;
340 x -= NETEM_DIST_SCALE/2;
342 return x / NETEM_DIST_SCALE + (sigma / NETEM_DIST_SCALE) * t + mu;
345 static u64 packet_time_ns(u64 len, const struct netem_sched_data *q)
347 len += q->packet_overhead;
350 u32 cells = reciprocal_divide(len, q->cell_size_reciprocal);
352 if (len > cells * q->cell_size) /* extra cell needed for remainder */
354 len = cells * (q->cell_size + q->cell_overhead);
357 return div64_u64(len * NSEC_PER_SEC, q->rate);
360 static void tfifo_reset(struct Qdisc *sch)
362 struct netem_sched_data *q = qdisc_priv(sch);
363 struct rb_node *p = rb_first(&q->t_root);
366 struct sk_buff *skb = rb_to_skb(p);
369 rb_erase(&skb->rbnode, &q->t_root);
370 rtnl_kfree_skbs(skb, skb);
374 static void tfifo_enqueue(struct sk_buff *nskb, struct Qdisc *sch)
376 struct netem_sched_data *q = qdisc_priv(sch);
377 u64 tnext = netem_skb_cb(nskb)->time_to_send;
378 struct rb_node **p = &q->t_root.rb_node, *parent = NULL;
384 skb = rb_to_skb(parent);
385 if (tnext >= netem_skb_cb(skb)->time_to_send)
386 p = &parent->rb_right;
388 p = &parent->rb_left;
390 rb_link_node(&nskb->rbnode, parent, p);
391 rb_insert_color(&nskb->rbnode, &q->t_root);
395 /* netem can't properly corrupt a megapacket (like we get from GSO), so instead
396 * when we statistically choose to corrupt one, we instead segment it, returning
397 * the first packet to be corrupted, and re-enqueue the remaining frames
399 static struct sk_buff *netem_segment(struct sk_buff *skb, struct Qdisc *sch,
400 struct sk_buff **to_free)
402 struct sk_buff *segs;
403 netdev_features_t features = netif_skb_features(skb);
405 segs = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK);
407 if (IS_ERR_OR_NULL(segs)) {
408 qdisc_drop(skb, sch, to_free);
415 static void netem_enqueue_skb_head(struct qdisc_skb_head *qh, struct sk_buff *skb)
417 skb->next = qh->head;
426 * Insert one skb into qdisc.
427 * Note: parent depends on return value to account for queue length.
428 * NET_XMIT_DROP: queue length didn't change.
429 * NET_XMIT_SUCCESS: one skb was queued.
431 static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
432 struct sk_buff **to_free)
434 struct netem_sched_data *q = qdisc_priv(sch);
435 /* We don't fill cb now as skb_unshare() may invalidate it */
436 struct netem_skb_cb *cb;
437 struct sk_buff *skb2;
438 struct sk_buff *segs = NULL;
439 unsigned int len = 0, last_len, prev_len = qdisc_pkt_len(skb);
442 int rc = NET_XMIT_SUCCESS;
444 /* Random duplication */
445 if (q->duplicate && q->duplicate >= get_crandom(&q->dup_cor))
450 if (q->ecn && INET_ECN_set_ce(skb))
451 qdisc_qstats_drop(sch); /* mark packet */
456 qdisc_qstats_drop(sch);
457 __qdisc_drop(skb, to_free);
458 return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
461 /* If a delay is expected, orphan the skb. (orphaning usually takes
462 * place at TX completion time, so _before_ the link transit delay)
464 if (q->latency || q->jitter || q->rate)
465 skb_orphan_partial(skb);
468 * If we need to duplicate packet, then re-insert at top of the
469 * qdisc tree, since parent queuer expects that only one
470 * skb will be queued.
472 if (count > 1 && (skb2 = skb_clone(skb, GFP_ATOMIC)) != NULL) {
473 struct Qdisc *rootq = qdisc_root(sch);
474 u32 dupsave = q->duplicate; /* prevent duplicating a dup... */
477 rootq->enqueue(skb2, rootq, to_free);
478 q->duplicate = dupsave;
482 * Randomized packet corruption.
483 * Make copy if needed since we are modifying
484 * If packet is going to be hardware checksummed, then
485 * do it now in software before we mangle it.
487 if (q->corrupt && q->corrupt >= get_crandom(&q->corrupt_cor)) {
488 if (skb_is_gso(skb)) {
489 segs = netem_segment(skb, sch, to_free);
491 return NET_XMIT_DROP;
499 skb = skb_unshare(skb, GFP_ATOMIC);
500 if (unlikely(!skb)) {
501 qdisc_qstats_drop(sch);
504 if (skb->ip_summed == CHECKSUM_PARTIAL &&
505 skb_checksum_help(skb)) {
506 qdisc_drop(skb, sch, to_free);
510 skb->data[prandom_u32() % skb_headlen(skb)] ^=
511 1<<(prandom_u32() % 8);
514 if (unlikely(sch->q.qlen >= sch->limit))
515 return qdisc_drop_all(skb, sch, to_free);
517 qdisc_qstats_backlog_inc(sch, skb);
519 cb = netem_skb_cb(skb);
520 if (q->gap == 0 || /* not doing reordering */
521 q->counter < q->gap - 1 || /* inside last reordering gap */
522 q->reorder < get_crandom(&q->reorder_cor)) {
526 delay = tabledist(q->latency, q->jitter,
527 &q->delay_cor, q->delay_dist);
529 now = ktime_get_ns();
532 struct netem_skb_cb *last = NULL;
535 last = netem_skb_cb(sch->q.tail);
536 if (q->t_root.rb_node) {
537 struct sk_buff *t_skb;
538 struct netem_skb_cb *t_last;
540 t_skb = skb_rb_last(&q->t_root);
541 t_last = netem_skb_cb(t_skb);
543 t_last->time_to_send > last->time_to_send) {
550 * Last packet in queue is reference point (now),
551 * calculate this time bonus and subtract
554 delay -= last->time_to_send - now;
555 delay = max_t(s64, 0, delay);
556 now = last->time_to_send;
559 delay += packet_time_ns(qdisc_pkt_len(skb), q);
562 cb->time_to_send = now + delay;
564 tfifo_enqueue(skb, sch);
567 * Do re-ordering by putting one out of N packets at the front
570 cb->time_to_send = ktime_get_ns();
573 netem_enqueue_skb_head(&sch->q, skb);
574 sch->qstats.requeues++;
582 qdisc_skb_cb(segs)->pkt_len = segs->len;
583 last_len = segs->len;
584 rc = qdisc_enqueue(segs, sch, to_free);
585 if (rc != NET_XMIT_SUCCESS) {
586 if (net_xmit_drop_count(rc))
587 qdisc_qstats_drop(sch);
596 qdisc_tree_reduce_backlog(sch, 1 - nb, prev_len - len);
598 return NET_XMIT_SUCCESS;
601 /* Delay the next round with a new future slot with a
602 * correct number of bytes and packets.
605 static void get_slot_next(struct netem_sched_data *q, u64 now)
610 next_delay = q->slot_config.min_delay +
612 (q->slot_config.max_delay -
613 q->slot_config.min_delay) >> 32);
615 next_delay = tabledist(q->slot_config.dist_delay,
616 (s32)(q->slot_config.dist_jitter),
619 q->slot.slot_next = now + next_delay;
620 q->slot.packets_left = q->slot_config.max_packets;
621 q->slot.bytes_left = q->slot_config.max_bytes;
624 static struct sk_buff *netem_dequeue(struct Qdisc *sch)
626 struct netem_sched_data *q = qdisc_priv(sch);
631 skb = __qdisc_dequeue_head(&sch->q);
633 qdisc_qstats_backlog_dec(sch, skb);
635 qdisc_bstats_update(sch, skb);
638 p = rb_first(&q->t_root);
641 u64 now = ktime_get_ns();
645 /* if more time remaining? */
646 time_to_send = netem_skb_cb(skb)->time_to_send;
647 if (q->slot.slot_next && q->slot.slot_next < time_to_send)
648 get_slot_next(q, now);
650 if (time_to_send <= now && q->slot.slot_next <= now) {
651 rb_erase(p, &q->t_root);
653 qdisc_qstats_backlog_dec(sch, skb);
656 /* skb->dev shares skb->rbnode area,
657 * we need to restore its value.
659 skb->dev = qdisc_dev(sch);
661 #ifdef CONFIG_NET_CLS_ACT
663 * If it's at ingress let's pretend the delay is
664 * from the network (tstamp will be updated).
666 if (skb->tc_redirected && skb->tc_from_ingress)
670 if (q->slot.slot_next) {
671 q->slot.packets_left--;
672 q->slot.bytes_left -= qdisc_pkt_len(skb);
673 if (q->slot.packets_left <= 0 ||
674 q->slot.bytes_left <= 0)
675 get_slot_next(q, now);
679 unsigned int pkt_len = qdisc_pkt_len(skb);
680 struct sk_buff *to_free = NULL;
683 err = qdisc_enqueue(skb, q->qdisc, &to_free);
684 kfree_skb_list(to_free);
685 if (err != NET_XMIT_SUCCESS &&
686 net_xmit_drop_count(err)) {
687 qdisc_qstats_drop(sch);
688 qdisc_tree_reduce_backlog(sch, 1,
697 skb = q->qdisc->ops->dequeue(q->qdisc);
702 qdisc_watchdog_schedule_ns(&q->watchdog,
708 skb = q->qdisc->ops->dequeue(q->qdisc);
715 static void netem_reset(struct Qdisc *sch)
717 struct netem_sched_data *q = qdisc_priv(sch);
719 qdisc_reset_queue(sch);
722 qdisc_reset(q->qdisc);
723 qdisc_watchdog_cancel(&q->watchdog);
726 static void dist_free(struct disttable *d)
732 * Distribution data is a variable size payload containing
733 * signed 16 bit values.
736 static int get_dist_table(struct Qdisc *sch, struct disttable **tbl,
737 const struct nlattr *attr)
739 size_t n = nla_len(attr)/sizeof(__s16);
740 const __s16 *data = nla_data(attr);
741 spinlock_t *root_lock;
745 if (n > NETEM_DIST_MAX)
748 d = kvmalloc(sizeof(struct disttable) + n * sizeof(s16), GFP_KERNEL);
753 for (i = 0; i < n; i++)
754 d->table[i] = data[i];
756 root_lock = qdisc_root_sleeping_lock(sch);
758 spin_lock_bh(root_lock);
760 spin_unlock_bh(root_lock);
766 static void get_slot(struct netem_sched_data *q, const struct nlattr *attr)
768 const struct tc_netem_slot *c = nla_data(attr);
771 if (q->slot_config.max_packets == 0)
772 q->slot_config.max_packets = INT_MAX;
773 if (q->slot_config.max_bytes == 0)
774 q->slot_config.max_bytes = INT_MAX;
775 q->slot.packets_left = q->slot_config.max_packets;
776 q->slot.bytes_left = q->slot_config.max_bytes;
777 if (q->slot_config.min_delay | q->slot_config.max_delay |
778 q->slot_config.dist_jitter)
779 q->slot.slot_next = ktime_get_ns();
781 q->slot.slot_next = 0;
784 static void get_correlation(struct netem_sched_data *q, const struct nlattr *attr)
786 const struct tc_netem_corr *c = nla_data(attr);
788 init_crandom(&q->delay_cor, c->delay_corr);
789 init_crandom(&q->loss_cor, c->loss_corr);
790 init_crandom(&q->dup_cor, c->dup_corr);
793 static void get_reorder(struct netem_sched_data *q, const struct nlattr *attr)
795 const struct tc_netem_reorder *r = nla_data(attr);
797 q->reorder = r->probability;
798 init_crandom(&q->reorder_cor, r->correlation);
801 static void get_corrupt(struct netem_sched_data *q, const struct nlattr *attr)
803 const struct tc_netem_corrupt *r = nla_data(attr);
805 q->corrupt = r->probability;
806 init_crandom(&q->corrupt_cor, r->correlation);
809 static void get_rate(struct netem_sched_data *q, const struct nlattr *attr)
811 const struct tc_netem_rate *r = nla_data(attr);
814 q->packet_overhead = r->packet_overhead;
815 q->cell_size = r->cell_size;
816 q->cell_overhead = r->cell_overhead;
818 q->cell_size_reciprocal = reciprocal_value(q->cell_size);
820 q->cell_size_reciprocal = (struct reciprocal_value) { 0 };
823 static int get_loss_clg(struct netem_sched_data *q, const struct nlattr *attr)
825 const struct nlattr *la;
828 nla_for_each_nested(la, attr, rem) {
829 u16 type = nla_type(la);
832 case NETEM_LOSS_GI: {
833 const struct tc_netem_gimodel *gi = nla_data(la);
835 if (nla_len(la) < sizeof(struct tc_netem_gimodel)) {
836 pr_info("netem: incorrect gi model size\n");
840 q->loss_model = CLG_4_STATES;
842 q->clg.state = TX_IN_GAP_PERIOD;
851 case NETEM_LOSS_GE: {
852 const struct tc_netem_gemodel *ge = nla_data(la);
854 if (nla_len(la) < sizeof(struct tc_netem_gemodel)) {
855 pr_info("netem: incorrect ge model size\n");
859 q->loss_model = CLG_GILB_ELL;
860 q->clg.state = GOOD_STATE;
869 pr_info("netem: unknown loss type %u\n", type);
877 static const struct nla_policy netem_policy[TCA_NETEM_MAX + 1] = {
878 [TCA_NETEM_CORR] = { .len = sizeof(struct tc_netem_corr) },
879 [TCA_NETEM_REORDER] = { .len = sizeof(struct tc_netem_reorder) },
880 [TCA_NETEM_CORRUPT] = { .len = sizeof(struct tc_netem_corrupt) },
881 [TCA_NETEM_RATE] = { .len = sizeof(struct tc_netem_rate) },
882 [TCA_NETEM_LOSS] = { .type = NLA_NESTED },
883 [TCA_NETEM_ECN] = { .type = NLA_U32 },
884 [TCA_NETEM_RATE64] = { .type = NLA_U64 },
885 [TCA_NETEM_LATENCY64] = { .type = NLA_S64 },
886 [TCA_NETEM_JITTER64] = { .type = NLA_S64 },
887 [TCA_NETEM_SLOT] = { .len = sizeof(struct tc_netem_slot) },
890 static int parse_attr(struct nlattr *tb[], int maxtype, struct nlattr *nla,
891 const struct nla_policy *policy, int len)
893 int nested_len = nla_len(nla) - NLA_ALIGN(len);
895 if (nested_len < 0) {
896 pr_info("netem: invalid attributes len %d\n", nested_len);
900 if (nested_len >= nla_attr_size(0))
901 return nla_parse(tb, maxtype, nla_data(nla) + NLA_ALIGN(len),
902 nested_len, policy, NULL);
904 memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
908 /* Parse netlink message to set options */
909 static int netem_change(struct Qdisc *sch, struct nlattr *opt,
910 struct netlink_ext_ack *extack)
912 struct netem_sched_data *q = qdisc_priv(sch);
913 struct nlattr *tb[TCA_NETEM_MAX + 1];
914 struct tc_netem_qopt *qopt;
915 struct clgstate old_clg;
916 int old_loss_model = CLG_RANDOM;
922 qopt = nla_data(opt);
923 ret = parse_attr(tb, TCA_NETEM_MAX, opt, netem_policy, sizeof(*qopt));
927 /* backup q->clg and q->loss_model */
929 old_loss_model = q->loss_model;
931 if (tb[TCA_NETEM_LOSS]) {
932 ret = get_loss_clg(q, tb[TCA_NETEM_LOSS]);
934 q->loss_model = old_loss_model;
938 q->loss_model = CLG_RANDOM;
941 if (tb[TCA_NETEM_DELAY_DIST]) {
942 ret = get_dist_table(sch, &q->delay_dist,
943 tb[TCA_NETEM_DELAY_DIST]);
945 goto get_table_failure;
948 if (tb[TCA_NETEM_SLOT_DIST]) {
949 ret = get_dist_table(sch, &q->slot_dist,
950 tb[TCA_NETEM_SLOT_DIST]);
952 goto get_table_failure;
955 sch->limit = qopt->limit;
957 q->latency = PSCHED_TICKS2NS(qopt->latency);
958 q->jitter = PSCHED_TICKS2NS(qopt->jitter);
959 q->limit = qopt->limit;
962 q->loss = qopt->loss;
963 q->duplicate = qopt->duplicate;
965 /* for compatibility with earlier versions.
966 * if gap is set, need to assume 100% probability
971 if (tb[TCA_NETEM_CORR])
972 get_correlation(q, tb[TCA_NETEM_CORR]);
974 if (tb[TCA_NETEM_REORDER])
975 get_reorder(q, tb[TCA_NETEM_REORDER]);
977 if (tb[TCA_NETEM_CORRUPT])
978 get_corrupt(q, tb[TCA_NETEM_CORRUPT]);
980 if (tb[TCA_NETEM_RATE])
981 get_rate(q, tb[TCA_NETEM_RATE]);
983 if (tb[TCA_NETEM_RATE64])
984 q->rate = max_t(u64, q->rate,
985 nla_get_u64(tb[TCA_NETEM_RATE64]));
987 if (tb[TCA_NETEM_LATENCY64])
988 q->latency = nla_get_s64(tb[TCA_NETEM_LATENCY64]);
990 if (tb[TCA_NETEM_JITTER64])
991 q->jitter = nla_get_s64(tb[TCA_NETEM_JITTER64]);
993 if (tb[TCA_NETEM_ECN])
994 q->ecn = nla_get_u32(tb[TCA_NETEM_ECN]);
996 if (tb[TCA_NETEM_SLOT])
997 get_slot(q, tb[TCA_NETEM_SLOT]);
1002 /* recover clg and loss_model, in case of
1003 * q->clg and q->loss_model were modified
1007 q->loss_model = old_loss_model;
1011 static int netem_init(struct Qdisc *sch, struct nlattr *opt,
1012 struct netlink_ext_ack *extack)
1014 struct netem_sched_data *q = qdisc_priv(sch);
1017 qdisc_watchdog_init(&q->watchdog, sch);
1022 q->loss_model = CLG_RANDOM;
1023 ret = netem_change(sch, opt, extack);
1025 pr_info("netem: change failed\n");
1029 static void netem_destroy(struct Qdisc *sch)
1031 struct netem_sched_data *q = qdisc_priv(sch);
1033 qdisc_watchdog_cancel(&q->watchdog);
1035 qdisc_destroy(q->qdisc);
1036 dist_free(q->delay_dist);
1037 dist_free(q->slot_dist);
1040 static int dump_loss_model(const struct netem_sched_data *q,
1041 struct sk_buff *skb)
1043 struct nlattr *nest;
1045 nest = nla_nest_start(skb, TCA_NETEM_LOSS);
1047 goto nla_put_failure;
1049 switch (q->loss_model) {
1051 /* legacy loss model */
1052 nla_nest_cancel(skb, nest);
1053 return 0; /* no data */
1055 case CLG_4_STATES: {
1056 struct tc_netem_gimodel gi = {
1064 if (nla_put(skb, NETEM_LOSS_GI, sizeof(gi), &gi))
1065 goto nla_put_failure;
1068 case CLG_GILB_ELL: {
1069 struct tc_netem_gemodel ge = {
1076 if (nla_put(skb, NETEM_LOSS_GE, sizeof(ge), &ge))
1077 goto nla_put_failure;
1082 nla_nest_end(skb, nest);
1086 nla_nest_cancel(skb, nest);
1090 static int netem_dump(struct Qdisc *sch, struct sk_buff *skb)
1092 const struct netem_sched_data *q = qdisc_priv(sch);
1093 struct nlattr *nla = (struct nlattr *) skb_tail_pointer(skb);
1094 struct tc_netem_qopt qopt;
1095 struct tc_netem_corr cor;
1096 struct tc_netem_reorder reorder;
1097 struct tc_netem_corrupt corrupt;
1098 struct tc_netem_rate rate;
1099 struct tc_netem_slot slot;
1101 qopt.latency = min_t(psched_tdiff_t, PSCHED_NS2TICKS(q->latency),
1103 qopt.jitter = min_t(psched_tdiff_t, PSCHED_NS2TICKS(q->jitter),
1105 qopt.limit = q->limit;
1106 qopt.loss = q->loss;
1108 qopt.duplicate = q->duplicate;
1109 if (nla_put(skb, TCA_OPTIONS, sizeof(qopt), &qopt))
1110 goto nla_put_failure;
1112 if (nla_put(skb, TCA_NETEM_LATENCY64, sizeof(q->latency), &q->latency))
1113 goto nla_put_failure;
1115 if (nla_put(skb, TCA_NETEM_JITTER64, sizeof(q->jitter), &q->jitter))
1116 goto nla_put_failure;
1118 cor.delay_corr = q->delay_cor.rho;
1119 cor.loss_corr = q->loss_cor.rho;
1120 cor.dup_corr = q->dup_cor.rho;
1121 if (nla_put(skb, TCA_NETEM_CORR, sizeof(cor), &cor))
1122 goto nla_put_failure;
1124 reorder.probability = q->reorder;
1125 reorder.correlation = q->reorder_cor.rho;
1126 if (nla_put(skb, TCA_NETEM_REORDER, sizeof(reorder), &reorder))
1127 goto nla_put_failure;
1129 corrupt.probability = q->corrupt;
1130 corrupt.correlation = q->corrupt_cor.rho;
1131 if (nla_put(skb, TCA_NETEM_CORRUPT, sizeof(corrupt), &corrupt))
1132 goto nla_put_failure;
1134 if (q->rate >= (1ULL << 32)) {
1135 if (nla_put_u64_64bit(skb, TCA_NETEM_RATE64, q->rate,
1137 goto nla_put_failure;
1140 rate.rate = q->rate;
1142 rate.packet_overhead = q->packet_overhead;
1143 rate.cell_size = q->cell_size;
1144 rate.cell_overhead = q->cell_overhead;
1145 if (nla_put(skb, TCA_NETEM_RATE, sizeof(rate), &rate))
1146 goto nla_put_failure;
1148 if (q->ecn && nla_put_u32(skb, TCA_NETEM_ECN, q->ecn))
1149 goto nla_put_failure;
1151 if (dump_loss_model(q, skb) != 0)
1152 goto nla_put_failure;
1154 if (q->slot_config.min_delay | q->slot_config.max_delay |
1155 q->slot_config.dist_jitter) {
1156 slot = q->slot_config;
1157 if (slot.max_packets == INT_MAX)
1158 slot.max_packets = 0;
1159 if (slot.max_bytes == INT_MAX)
1161 if (nla_put(skb, TCA_NETEM_SLOT, sizeof(slot), &slot))
1162 goto nla_put_failure;
1165 return nla_nest_end(skb, nla);
1168 nlmsg_trim(skb, nla);
1172 static int netem_dump_class(struct Qdisc *sch, unsigned long cl,
1173 struct sk_buff *skb, struct tcmsg *tcm)
1175 struct netem_sched_data *q = qdisc_priv(sch);
1177 if (cl != 1 || !q->qdisc) /* only one class */
1180 tcm->tcm_handle |= TC_H_MIN(1);
1181 tcm->tcm_info = q->qdisc->handle;
1186 static int netem_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
1187 struct Qdisc **old, struct netlink_ext_ack *extack)
1189 struct netem_sched_data *q = qdisc_priv(sch);
1191 *old = qdisc_replace(sch, new, &q->qdisc);
1195 static struct Qdisc *netem_leaf(struct Qdisc *sch, unsigned long arg)
1197 struct netem_sched_data *q = qdisc_priv(sch);
1201 static unsigned long netem_find(struct Qdisc *sch, u32 classid)
1206 static void netem_walk(struct Qdisc *sch, struct qdisc_walker *walker)
1208 if (!walker->stop) {
1209 if (walker->count >= walker->skip)
1210 if (walker->fn(sch, 1, walker) < 0) {
1218 static const struct Qdisc_class_ops netem_class_ops = {
1219 .graft = netem_graft,
1223 .dump = netem_dump_class,
1226 static struct Qdisc_ops netem_qdisc_ops __read_mostly = {
1228 .cl_ops = &netem_class_ops,
1229 .priv_size = sizeof(struct netem_sched_data),
1230 .enqueue = netem_enqueue,
1231 .dequeue = netem_dequeue,
1232 .peek = qdisc_peek_dequeued,
1234 .reset = netem_reset,
1235 .destroy = netem_destroy,
1236 .change = netem_change,
1238 .owner = THIS_MODULE,
1242 static int __init netem_module_init(void)
1244 pr_info("netem: version " VERSION "\n");
1245 return register_qdisc(&netem_qdisc_ops);
1247 static void __exit netem_module_exit(void)
1249 unregister_qdisc(&netem_qdisc_ops);
1251 module_init(netem_module_init)
1252 module_exit(netem_module_exit)
1253 MODULE_LICENSE("GPL");