2 * net/sched/sch_gred.c Generic Random Early Detection queue.
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License
7 * as published by the Free Software Foundation; either version
8 * 2 of the License, or (at your option) any later version.
10 * Authors: J Hadi Salim (hadi@cyberus.ca) 1998-2002
12 * 991129: - Bug fix with grio mode
13 * - a better sing. AvgQ mode with Grio(WRED)
14 * - A finer grained VQ dequeue based on sugestion
20 * For all the glorious comments look at Alexey's sch_red.c
23 #include <linux/config.h>
24 #include <linux/module.h>
25 #include <asm/uaccess.h>
26 #include <asm/system.h>
27 #include <linux/bitops.h>
28 #include <linux/types.h>
29 #include <linux/kernel.h>
30 #include <linux/sched.h>
31 #include <linux/string.h>
33 #include <linux/socket.h>
34 #include <linux/sockios.h>
36 #include <linux/errno.h>
37 #include <linux/interrupt.h>
38 #include <linux/if_ether.h>
39 #include <linux/inet.h>
40 #include <linux/netdevice.h>
41 #include <linux/etherdevice.h>
42 #include <linux/notifier.h>
44 #include <net/route.h>
45 #include <linux/skbuff.h>
47 #include <net/pkt_sched.h>
51 #define DPRINTK(format,args...) printk(KERN_DEBUG format,##args)
53 #define DPRINTK(format,args...)
57 #define D2PRINTK(format,args...) printk(KERN_DEBUG format,##args)
59 #define D2PRINTK(format,args...)
62 #define GRED_DEF_PRIO (MAX_DPs / 2)
63 #define GRED_VQ_MASK (MAX_DPs - 1)
65 struct gred_sched_data;
68 struct gred_sched_data
70 u32 limit; /* HARD maximal queue length */
71 u32 DP; /* the drop pramaters */
72 u32 bytesin; /* bytes seen on virtualQ so far*/
73 u32 packetsin; /* packets seen on virtualQ so far*/
74 u32 backlog; /* bytes on the virtualQ */
75 u8 prio; /* the prio of this vq */
77 struct red_parms parms;
78 struct red_stats stats;
88 struct gred_sched_data *tab[MAX_DPs];
94 static inline int gred_wred_mode(struct gred_sched *table)
96 return test_bit(GRED_WRED_MODE, &table->flags);
99 static inline void gred_enable_wred_mode(struct gred_sched *table)
101 __set_bit(GRED_WRED_MODE, &table->flags);
104 static inline void gred_disable_wred_mode(struct gred_sched *table)
106 __clear_bit(GRED_WRED_MODE, &table->flags);
109 static inline int gred_rio_mode(struct gred_sched *table)
111 return test_bit(GRED_RIO_MODE, &table->flags);
114 static inline void gred_enable_rio_mode(struct gred_sched *table)
116 __set_bit(GRED_RIO_MODE, &table->flags);
119 static inline void gred_disable_rio_mode(struct gred_sched *table)
121 __clear_bit(GRED_RIO_MODE, &table->flags);
124 static inline int gred_wred_mode_check(struct Qdisc *sch)
126 struct gred_sched *table = qdisc_priv(sch);
129 /* Really ugly O(n^2) but shouldn't be necessary too frequent. */
130 for (i = 0; i < table->DPs; i++) {
131 struct gred_sched_data *q = table->tab[i];
137 for (n = 0; n < table->DPs; n++)
138 if (table->tab[n] && table->tab[n] != q &&
139 table->tab[n]->prio == q->prio)
146 static inline unsigned int gred_backlog(struct gred_sched *table,
147 struct gred_sched_data *q,
150 if (gred_wred_mode(table))
151 return sch->qstats.backlog;
156 static inline u16 tc_index_to_dp(struct sk_buff *skb)
158 return skb->tc_index & GRED_VQ_MASK;
162 gred_enqueue(struct sk_buff *skb, struct Qdisc* sch)
164 struct gred_sched_data *q=NULL;
165 struct gred_sched *t= qdisc_priv(sch);
166 unsigned long qavg = 0;
168 u16 dp = tc_index_to_dp(skb);
170 if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
173 if ((q = t->tab[dp]) == NULL) {
174 /* Pass through packets not assigned to a DP
175 * if no default DP has been configured. This
176 * allows for DP flows to be left untouched.
178 if (skb_queue_len(&sch->q) < sch->dev->tx_queue_len)
179 return qdisc_enqueue_tail(skb, sch);
184 /* fix tc_index? --could be controvesial but needed for
186 skb->tc_index = (skb->tc_index & ~GRED_VQ_MASK) | dp;
189 /* sum up all the qaves of prios <= to ours to get the new qave*/
190 if (!gred_wred_mode(t) && gred_rio_mode(t)) {
191 for (i=0;i<t->DPs;i++) {
192 if ((!t->tab[i]) || (i==q->DP))
195 if (t->tab[i]->prio < q->prio &&
196 !red_is_idling(&t->tab[i]->parms))
197 qavg +=t->tab[i]->parms.qavg;
203 q->bytesin+=skb->len;
205 if (gred_wred_mode(t)) {
207 q->parms.qavg = t->tab[t->def]->parms.qavg;
208 q->parms.qidlestart = t->tab[t->def]->parms.qidlestart;
211 q->parms.qavg = red_calc_qavg(&q->parms, gred_backlog(t, q, sch));
213 if (red_is_idling(&q->parms))
214 red_end_of_idle_period(&q->parms);
216 if (gred_wred_mode(t))
217 t->tab[t->def]->parms.qavg = q->parms.qavg;
219 switch (red_action(&q->parms, q->parms.qavg + qavg)) {
224 sch->qstats.overlimits++;
225 q->stats.prob_drop++;
226 goto congestion_drop;
229 sch->qstats.overlimits++;
230 q->stats.forced_drop++;
231 goto congestion_drop;
234 if (q->backlog + skb->len <= q->limit) {
235 q->backlog += skb->len;
236 return qdisc_enqueue_tail(skb, sch);
241 return qdisc_drop(skb, sch);
244 qdisc_drop(skb, sch);
249 gred_requeue(struct sk_buff *skb, struct Qdisc* sch)
251 struct gred_sched *t = qdisc_priv(sch);
252 struct gred_sched_data *q;
253 u16 dp = tc_index_to_dp(skb);
255 if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
257 printk(KERN_WARNING "GRED: Unable to relocate VQ 0x%x "
258 "for requeue, screwing up backlog.\n",
259 tc_index_to_dp(skb));
261 if (red_is_idling(&q->parms))
262 red_end_of_idle_period(&q->parms);
263 q->backlog += skb->len;
266 return qdisc_requeue(skb, sch);
269 static struct sk_buff *
270 gred_dequeue(struct Qdisc* sch)
273 struct gred_sched_data *q;
274 struct gred_sched *t= qdisc_priv(sch);
276 skb = qdisc_dequeue_head(sch);
279 u16 dp = tc_index_to_dp(skb);
281 if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
283 printk(KERN_WARNING "GRED: Unable to relocate "
284 "VQ 0x%x after dequeue, screwing up "
285 "backlog.\n", tc_index_to_dp(skb));
287 q->backlog -= skb->len;
289 if (!q->backlog && !gred_wred_mode(t))
290 red_start_of_idle_period(&q->parms);
296 if (gred_wred_mode(t)) {
299 D2PRINTK("no default VQ set: Results will be "
302 red_start_of_idle_period(&q->parms);
308 static unsigned int gred_drop(struct Qdisc* sch)
312 struct gred_sched_data *q;
313 struct gred_sched *t= qdisc_priv(sch);
315 skb = qdisc_dequeue_tail(sch);
317 unsigned int len = skb->len;
318 u16 dp = tc_index_to_dp(skb);
320 if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
322 printk(KERN_WARNING "GRED: Unable to relocate "
323 "VQ 0x%x while dropping, screwing up "
324 "backlog.\n", tc_index_to_dp(skb));
329 if (!q->backlog && !gred_wred_mode(t))
330 red_start_of_idle_period(&q->parms);
333 qdisc_drop(skb, sch);
339 D2PRINTK("no default VQ set: Results might be screwed up\n");
343 red_start_of_idle_period(&q->parms);
348 static void gred_reset(struct Qdisc* sch)
351 struct gred_sched_data *q;
352 struct gred_sched *t= qdisc_priv(sch);
354 qdisc_reset_queue(sch);
356 for (i=0;i<t->DPs;i++) {
360 red_restart(&q->parms);
365 static inline void gred_destroy_vq(struct gred_sched_data *q)
370 static inline int gred_change_table_def(struct Qdisc *sch, struct rtattr *dps)
372 struct gred_sched *table = qdisc_priv(sch);
373 struct tc_gred_sopt *sopt;
376 if (dps == NULL || RTA_PAYLOAD(dps) < sizeof(*sopt))
379 sopt = RTA_DATA(dps);
381 if (sopt->DPs > MAX_DPs || sopt->DPs == 0 || sopt->def_DP >= sopt->DPs)
385 table->DPs = sopt->DPs;
386 table->def = sopt->def_DP;
389 * Every entry point to GRED is synchronized with the above code
390 * and the DP is checked against DPs, i.e. shadowed VQs can no
391 * longer be found so we can unlock right here.
393 sch_tree_unlock(sch);
396 gred_enable_rio_mode(table);
397 gred_disable_wred_mode(table);
398 if (gred_wred_mode_check(sch))
399 gred_enable_wred_mode(table);
401 gred_disable_rio_mode(table);
402 gred_disable_wred_mode(table);
405 for (i = table->DPs; i < MAX_DPs; i++) {
407 printk(KERN_WARNING "GRED: Warning: Destroying "
408 "shadowed VQ 0x%x\n", i);
409 gred_destroy_vq(table->tab[i]);
410 table->tab[i] = NULL;
417 static inline int gred_change_vq(struct Qdisc *sch, int dp,
418 struct tc_gred_qopt *ctl, int prio, u8 *stab)
420 struct gred_sched *table = qdisc_priv(sch);
421 struct gred_sched_data *q;
423 if (table->tab[dp] == NULL) {
424 table->tab[dp] = kmalloc(sizeof(*q), GFP_KERNEL);
425 if (table->tab[dp] == NULL)
427 memset(table->tab[dp], 0, sizeof(*q));
433 q->limit = ctl->limit;
436 red_end_of_idle_period(&q->parms);
438 red_set_parms(&q->parms,
439 ctl->qth_min, ctl->qth_max, ctl->Wlog, ctl->Plog,
440 ctl->Scell_log, stab);
445 static int gred_change(struct Qdisc *sch, struct rtattr *opt)
447 struct gred_sched *table = qdisc_priv(sch);
448 struct tc_gred_qopt *ctl;
449 struct rtattr *tb[TCA_GRED_MAX];
450 int err = -EINVAL, prio = GRED_DEF_PRIO;
453 if (opt == NULL || rtattr_parse_nested(tb, TCA_GRED_MAX, opt))
456 if (tb[TCA_GRED_PARMS-1] == NULL && tb[TCA_GRED_STAB-1] == NULL)
457 return gred_change_table_def(sch, opt);
459 if (tb[TCA_GRED_PARMS-1] == NULL ||
460 RTA_PAYLOAD(tb[TCA_GRED_PARMS-1]) < sizeof(*ctl) ||
461 tb[TCA_GRED_STAB-1] == NULL ||
462 RTA_PAYLOAD(tb[TCA_GRED_STAB-1]) < 256)
465 ctl = RTA_DATA(tb[TCA_GRED_PARMS-1]);
466 stab = RTA_DATA(tb[TCA_GRED_STAB-1]);
468 if (ctl->DP >= table->DPs)
471 if (gred_rio_mode(table)) {
472 if (ctl->prio == 0) {
473 int def_prio = GRED_DEF_PRIO;
475 if (table->tab[table->def])
476 def_prio = table->tab[table->def]->prio;
478 printk(KERN_DEBUG "GRED: DP %u does not have a prio "
479 "setting default to %d\n", ctl->DP, def_prio);
488 err = gred_change_vq(sch, ctl->DP, ctl, prio, stab);
492 if (table->tab[table->def] == NULL) {
493 if (gred_rio_mode(table))
494 prio = table->tab[ctl->DP]->prio;
496 err = gred_change_vq(sch, table->def, ctl, prio, stab);
501 if (gred_rio_mode(table)) {
502 gred_disable_wred_mode(table);
503 if (gred_wred_mode_check(sch))
504 gred_enable_wred_mode(table);
510 sch_tree_unlock(sch);
515 static int gred_init(struct Qdisc *sch, struct rtattr *opt)
517 struct rtattr *tb[TCA_GRED_MAX];
519 if (opt == NULL || rtattr_parse_nested(tb, TCA_GRED_MAX, opt))
522 if (tb[TCA_GRED_PARMS-1] || tb[TCA_GRED_STAB-1])
525 return gred_change_table_def(sch, tb[TCA_GRED_DPS-1]);
528 static int gred_dump(struct Qdisc *sch, struct sk_buff *skb)
530 struct gred_sched *table = qdisc_priv(sch);
531 struct rtattr *parms, *opts = NULL;
533 struct tc_gred_sopt sopt = {
535 .def_DP = table->def,
536 .grio = gred_rio_mode(table),
539 opts = RTA_NEST(skb, TCA_OPTIONS);
540 RTA_PUT(skb, TCA_GRED_DPS, sizeof(sopt), &sopt);
541 parms = RTA_NEST(skb, TCA_GRED_PARMS);
543 for (i = 0; i < MAX_DPs; i++) {
544 struct gred_sched_data *q = table->tab[i];
545 struct tc_gred_qopt opt;
547 memset(&opt, 0, sizeof(opt));
550 /* hack -- fix at some point with proper message
551 This is how we indicate to tc that there is no VQ
554 opt.DP = MAX_DPs + i;
558 opt.limit = q->limit;
560 opt.backlog = q->backlog;
562 opt.qth_min = q->parms.qth_min >> q->parms.Wlog;
563 opt.qth_max = q->parms.qth_max >> q->parms.Wlog;
564 opt.Wlog = q->parms.Wlog;
565 opt.Plog = q->parms.Plog;
566 opt.Scell_log = q->parms.Scell_log;
567 opt.other = q->stats.other;
568 opt.early = q->stats.prob_drop;
569 opt.forced = q->stats.forced_drop;
570 opt.pdrop = q->stats.pdrop;
571 opt.packets = q->packetsin;
572 opt.bytesin = q->bytesin;
574 if (gred_wred_mode(table)) {
575 q->parms.qidlestart =
576 table->tab[table->def]->parms.qidlestart;
577 q->parms.qavg = table->tab[table->def]->parms.qavg;
580 opt.qave = red_calc_qavg(&q->parms, q->parms.qavg);
583 RTA_APPEND(skb, sizeof(opt), &opt);
586 RTA_NEST_END(skb, parms);
588 return RTA_NEST_END(skb, opts);
591 return RTA_NEST_CANCEL(skb, opts);
594 static void gred_destroy(struct Qdisc *sch)
596 struct gred_sched *table = qdisc_priv(sch);
599 for (i = 0;i < table->DPs; i++) {
601 gred_destroy_vq(table->tab[i]);
605 static struct Qdisc_ops gred_qdisc_ops = {
609 .priv_size = sizeof(struct gred_sched),
610 .enqueue = gred_enqueue,
611 .dequeue = gred_dequeue,
612 .requeue = gred_requeue,
616 .destroy = gred_destroy,
617 .change = gred_change,
619 .owner = THIS_MODULE,
622 static int __init gred_module_init(void)
624 return register_qdisc(&gred_qdisc_ops);
626 static void __exit gred_module_exit(void)
628 unregister_qdisc(&gred_qdisc_ops);
630 module_init(gred_module_init)
631 module_exit(gred_module_exit)
632 MODULE_LICENSE("GPL");