linux/net/sched/sch_gred.c

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/*
* net/sched/sch_gred.c Generic Random Early Detection queue.
*
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Authors: J Hadi Salim (hadi@cyberus.ca) 1998-2002
*
* 991129: - Bug fix with grio mode
* - a better sing. AvgQ mode with Grio(WRED)
* - A finer grained VQ dequeue based on sugestion
* from Ren Liu
* - More error checks
*
*
*
* For all the glorious comments look at Alexey's sch_red.c
*/
#include <linux/config.h>
#include <linux/module.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/bitops.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/in.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/if_ether.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/notifier.h>
#include <net/ip.h>
#include <net/route.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/pkt_sched.h>
#include <net/red.h>
#if 1 /* control */
#define DPRINTK(format,args...) printk(KERN_DEBUG format,##args)
#else
#define DPRINTK(format,args...)
#endif
#if 0 /* data */
#define D2PRINTK(format,args...) printk(KERN_DEBUG format,##args)
#else
#define D2PRINTK(format,args...)
#endif
#define GRED_DEF_PRIO (MAX_DPs / 2)
struct gred_sched_data;
struct gred_sched;
struct gred_sched_data
{
u32 limit; /* HARD maximal queue length */
u32 DP; /* the drop pramaters */
u32 bytesin; /* bytes seen on virtualQ so far*/
u32 packetsin; /* packets seen on virtualQ so far*/
u32 backlog; /* bytes on the virtualQ */
u8 prio; /* the prio of this vq */
struct red_parms parms;
struct red_stats stats;
};
enum {
GRED_WRED_MODE = 1,
GRED_RIO_MODE,
};
struct gred_sched
{
struct gred_sched_data *tab[MAX_DPs];
unsigned long flags;
u32 DPs;
u32 def;
u8 initd;
};
static inline int gred_wred_mode(struct gred_sched *table)
{
return test_bit(GRED_WRED_MODE, &table->flags);
}
static inline void gred_enable_wred_mode(struct gred_sched *table)
{
__set_bit(GRED_WRED_MODE, &table->flags);
}
static inline void gred_disable_wred_mode(struct gred_sched *table)
{
__clear_bit(GRED_WRED_MODE, &table->flags);
}
static inline int gred_rio_mode(struct gred_sched *table)
{
return test_bit(GRED_RIO_MODE, &table->flags);
}
static inline void gred_enable_rio_mode(struct gred_sched *table)
{
__set_bit(GRED_RIO_MODE, &table->flags);
}
static inline void gred_disable_rio_mode(struct gred_sched *table)
{
__clear_bit(GRED_RIO_MODE, &table->flags);
}
static inline int gred_wred_mode_check(struct Qdisc *sch)
{
struct gred_sched *table = qdisc_priv(sch);
int i;
/* Really ugly O(n^2) but shouldn't be necessary too frequent. */
for (i = 0; i < table->DPs; i++) {
struct gred_sched_data *q = table->tab[i];
int n;
if (q == NULL)
continue;
for (n = 0; n < table->DPs; n++)
if (table->tab[n] && table->tab[n] != q &&
table->tab[n]->prio == q->prio)
return 1;
}
return 0;
}
static inline unsigned int gred_backlog(struct gred_sched *table,
struct gred_sched_data *q,
struct Qdisc *sch)
{
if (gred_wred_mode(table))
return sch->qstats.backlog;
else
return q->backlog;
}
static int
gred_enqueue(struct sk_buff *skb, struct Qdisc* sch)
{
struct gred_sched_data *q=NULL;
struct gred_sched *t= qdisc_priv(sch);
unsigned long qavg = 0;
int i=0;
if (!t->initd && skb_queue_len(&sch->q) < (sch->dev->tx_queue_len ? : 1)) {
D2PRINTK("NO GRED Queues setup yet! Enqueued anyway\n");
goto do_enqueue;
}
if ( ((skb->tc_index&0xf) > (t->DPs -1)) || !(q=t->tab[skb->tc_index&0xf])) {
printk("GRED: setting to default (%d)\n ",t->def);
if (!(q=t->tab[t->def])) {
DPRINTK("GRED: setting to default FAILED! dropping!! "
"(%d)\n ", t->def);
goto drop;
}
/* fix tc_index? --could be controvesial but needed for
requeueing */
skb->tc_index=(skb->tc_index&0xfffffff0) | t->def;
}
D2PRINTK("gred_enqueue virtualQ 0x%x classid %x backlog %d "
"general backlog %d\n",skb->tc_index&0xf,sch->handle,q->backlog,
sch->qstats.backlog);
/* sum up all the qaves of prios <= to ours to get the new qave*/
if (!gred_wred_mode(t) && gred_rio_mode(t)) {
for (i=0;i<t->DPs;i++) {
if ((!t->tab[i]) || (i==q->DP))
continue;
if (t->tab[i]->prio < q->prio &&
!red_is_idling(&t->tab[i]->parms))
qavg +=t->tab[i]->parms.qavg;
}
}
q->packetsin++;
q->bytesin+=skb->len;
if (gred_wred_mode(t)) {
qavg = 0;
q->parms.qavg = t->tab[t->def]->parms.qavg;
q->parms.qidlestart = t->tab[t->def]->parms.qidlestart;
}
q->parms.qavg = red_calc_qavg(&q->parms, gred_backlog(t, q, sch));
if (red_is_idling(&q->parms))
red_end_of_idle_period(&q->parms);
if (gred_wred_mode(t))
t->tab[t->def]->parms.qavg = q->parms.qavg;
switch (red_action(&q->parms, q->parms.qavg + qavg)) {
case RED_DONT_MARK:
break;
case RED_PROB_MARK:
sch->qstats.overlimits++;
q->stats.prob_drop++;
goto congestion_drop;
case RED_HARD_MARK:
sch->qstats.overlimits++;
q->stats.forced_drop++;
goto congestion_drop;
}
if (q->backlog + skb->len <= q->limit) {
q->backlog += skb->len;
do_enqueue:
__skb_queue_tail(&sch->q, skb);
sch->qstats.backlog += skb->len;
sch->bstats.bytes += skb->len;
sch->bstats.packets++;
return 0;
}
q->stats.pdrop++;
drop:
kfree_skb(skb);
sch->qstats.drops++;
return NET_XMIT_DROP;
congestion_drop:
kfree_skb(skb);
sch->qstats.drops++;
return NET_XMIT_CN;
}
static int
gred_requeue(struct sk_buff *skb, struct Qdisc* sch)
{
struct gred_sched_data *q;
struct gred_sched *t= qdisc_priv(sch);
q= t->tab[(skb->tc_index&0xf)];
/* error checking here -- probably unnecessary */
if (red_is_idling(&q->parms))
red_end_of_idle_period(&q->parms);
__skb_queue_head(&sch->q, skb);
sch->qstats.backlog += skb->len;
sch->qstats.requeues++;
q->backlog += skb->len;
return 0;
}
static struct sk_buff *
gred_dequeue(struct Qdisc* sch)
{
struct sk_buff *skb;
struct gred_sched_data *q;
struct gred_sched *t= qdisc_priv(sch);
skb = __skb_dequeue(&sch->q);
if (skb) {
sch->qstats.backlog -= skb->len;
q= t->tab[(skb->tc_index&0xf)];
if (q) {
q->backlog -= skb->len;
if (!q->backlog && !gred_wred_mode(t))
red_start_of_idle_period(&q->parms);
} else {
D2PRINTK("gred_dequeue: skb has bad tcindex %x\n",skb->tc_index&0xf);
}
return skb;
}
if (gred_wred_mode(t)) {
q= t->tab[t->def];
if (!q)
D2PRINTK("no default VQ set: Results will be "
"screwed up\n");
else
red_start_of_idle_period(&q->parms);
}
return NULL;
}
static unsigned int gred_drop(struct Qdisc* sch)
{
struct sk_buff *skb;
struct gred_sched_data *q;
struct gred_sched *t= qdisc_priv(sch);
skb = __skb_dequeue_tail(&sch->q);
if (skb) {
unsigned int len = skb->len;
sch->qstats.backlog -= len;
sch->qstats.drops++;
q= t->tab[(skb->tc_index&0xf)];
if (q) {
q->backlog -= len;
q->stats.other++;
if (!q->backlog && !gred_wred_mode(t))
red_start_of_idle_period(&q->parms);
} else {
D2PRINTK("gred_dequeue: skb has bad tcindex %x\n",skb->tc_index&0xf);
}
kfree_skb(skb);
return len;
}
q=t->tab[t->def];
if (!q) {
D2PRINTK("no default VQ set: Results might be screwed up\n");
return 0;
}
red_start_of_idle_period(&q->parms);
return 0;
}
static void gred_reset(struct Qdisc* sch)
{
int i;
struct gred_sched_data *q;
struct gred_sched *t= qdisc_priv(sch);
__skb_queue_purge(&sch->q);
sch->qstats.backlog = 0;
for (i=0;i<t->DPs;i++) {
q= t->tab[i];
if (!q)
continue;
red_restart(&q->parms);
q->backlog = 0;
}
}
static inline void gred_destroy_vq(struct gred_sched_data *q)
{
kfree(q);
}
static inline int gred_change_table_def(struct Qdisc *sch, struct rtattr *dps)
{
struct gred_sched *table = qdisc_priv(sch);
struct tc_gred_sopt *sopt;
int i;
if (dps == NULL || RTA_PAYLOAD(dps) < sizeof(*sopt))
return -EINVAL;
sopt = RTA_DATA(dps);
if (sopt->DPs > MAX_DPs || sopt->DPs == 0 || sopt->def_DP >= sopt->DPs)
return -EINVAL;
sch_tree_lock(sch);
table->DPs = sopt->DPs;
table->def = sopt->def_DP;
/*
* Every entry point to GRED is synchronized with the above code
* and the DP is checked against DPs, i.e. shadowed VQs can no
* longer be found so we can unlock right here.
*/
sch_tree_unlock(sch);
if (sopt->grio) {
gred_enable_rio_mode(table);
gred_disable_wred_mode(table);
if (gred_wred_mode_check(sch))
gred_enable_wred_mode(table);
} else {
gred_disable_rio_mode(table);
gred_disable_wred_mode(table);
}
for (i = table->DPs; i < MAX_DPs; i++) {
if (table->tab[i]) {
printk(KERN_WARNING "GRED: Warning: Destroying "
"shadowed VQ 0x%x\n", i);
gred_destroy_vq(table->tab[i]);
table->tab[i] = NULL;
}
}
table->initd = 0;
return 0;
}
static inline int gred_change_vq(struct Qdisc *sch, int dp,
struct tc_gred_qopt *ctl, int prio, u8 *stab)
{
struct gred_sched *table = qdisc_priv(sch);
struct gred_sched_data *q;
if (table->tab[dp] == NULL) {
table->tab[dp] = kmalloc(sizeof(*q), GFP_KERNEL);
if (table->tab[dp] == NULL)
return -ENOMEM;
memset(table->tab[dp], 0, sizeof(*q));
}
q = table->tab[dp];
q->DP = dp;
q->prio = prio;
q->limit = ctl->limit;
if (q->backlog == 0)
red_end_of_idle_period(&q->parms);
red_set_parms(&q->parms,
ctl->qth_min, ctl->qth_max, ctl->Wlog, ctl->Plog,
ctl->Scell_log, stab);
return 0;
}
static int gred_change(struct Qdisc *sch, struct rtattr *opt)
{
struct gred_sched *table = qdisc_priv(sch);
struct tc_gred_qopt *ctl;
struct rtattr *tb[TCA_GRED_MAX];
int err = -EINVAL, prio = GRED_DEF_PRIO;
u8 *stab;
if (opt == NULL || rtattr_parse_nested(tb, TCA_GRED_MAX, opt))
return -EINVAL;
if (tb[TCA_GRED_PARMS-1] == NULL && tb[TCA_GRED_STAB-1] == NULL)
return gred_change_table_def(sch, opt);
if (tb[TCA_GRED_PARMS-1] == NULL ||
RTA_PAYLOAD(tb[TCA_GRED_PARMS-1]) < sizeof(*ctl) ||
tb[TCA_GRED_STAB-1] == NULL ||
RTA_PAYLOAD(tb[TCA_GRED_STAB-1]) < 256)
return -EINVAL;
ctl = RTA_DATA(tb[TCA_GRED_PARMS-1]);
stab = RTA_DATA(tb[TCA_GRED_STAB-1]);
if (ctl->DP >= table->DPs)
goto errout;
if (gred_rio_mode(table)) {
if (ctl->prio == 0) {
int def_prio = GRED_DEF_PRIO;
if (table->tab[table->def])
def_prio = table->tab[table->def]->prio;
printk(KERN_DEBUG "GRED: DP %u does not have a prio "
"setting default to %d\n", ctl->DP, def_prio);
prio = def_prio;
} else
prio = ctl->prio;
}
sch_tree_lock(sch);
err = gred_change_vq(sch, ctl->DP, ctl, prio, stab);
if (err < 0)
goto errout_locked;
if (table->tab[table->def] == NULL) {
if (gred_rio_mode(table))
prio = table->tab[ctl->DP]->prio;
err = gred_change_vq(sch, table->def, ctl, prio, stab);
if (err < 0)
goto errout_locked;
}
table->initd = 1;
if (gred_rio_mode(table)) {
gred_disable_wred_mode(table);
if (gred_wred_mode_check(sch))
gred_enable_wred_mode(table);
}
err = 0;
errout_locked:
sch_tree_unlock(sch);
errout:
return err;
}
static int gred_init(struct Qdisc *sch, struct rtattr *opt)
{
struct rtattr *tb[TCA_GRED_MAX];
if (opt == NULL || rtattr_parse_nested(tb, TCA_GRED_MAX, opt))
return -EINVAL;
if (tb[TCA_GRED_PARMS-1] || tb[TCA_GRED_STAB-1])
return -EINVAL;
return gred_change_table_def(sch, tb[TCA_GRED_DPS-1]);
}
static int gred_dump(struct Qdisc *sch, struct sk_buff *skb)
{
struct gred_sched *table = qdisc_priv(sch);
struct rtattr *parms, *opts = NULL;
int i;
struct tc_gred_sopt sopt = {
.DPs = table->DPs,
.def_DP = table->def,
.grio = gred_rio_mode(table),
};
opts = RTA_NEST(skb, TCA_OPTIONS);
RTA_PUT(skb, TCA_GRED_DPS, sizeof(sopt), &sopt);
parms = RTA_NEST(skb, TCA_GRED_PARMS);
for (i = 0; i < MAX_DPs; i++) {
struct gred_sched_data *q = table->tab[i];
struct tc_gred_qopt opt;
memset(&opt, 0, sizeof(opt));
if (!q) {
/* hack -- fix at some point with proper message
This is how we indicate to tc that there is no VQ
at this DP */
opt.DP = MAX_DPs + i;
goto append_opt;
}
opt.limit = q->limit;
opt.DP = q->DP;
opt.backlog = q->backlog;
opt.prio = q->prio;
opt.qth_min = q->parms.qth_min >> q->parms.Wlog;
opt.qth_max = q->parms.qth_max >> q->parms.Wlog;
opt.Wlog = q->parms.Wlog;
opt.Plog = q->parms.Plog;
opt.Scell_log = q->parms.Scell_log;
opt.other = q->stats.other;
opt.early = q->stats.prob_drop;
opt.forced = q->stats.forced_drop;
opt.pdrop = q->stats.pdrop;
opt.packets = q->packetsin;
opt.bytesin = q->bytesin;
if (gred_wred_mode(table)) {
q->parms.qidlestart =
table->tab[table->def]->parms.qidlestart;
q->parms.qavg = table->tab[table->def]->parms.qavg;
}
opt.qave = red_calc_qavg(&q->parms, q->parms.qavg);
append_opt:
RTA_APPEND(skb, sizeof(opt), &opt);
}
RTA_NEST_END(skb, parms);
return RTA_NEST_END(skb, opts);
rtattr_failure:
return RTA_NEST_CANCEL(skb, opts);
}
static void gred_destroy(struct Qdisc *sch)
{
struct gred_sched *table = qdisc_priv(sch);
int i;
for (i = 0;i < table->DPs; i++) {
if (table->tab[i])
gred_destroy_vq(table->tab[i]);
}
}
static struct Qdisc_ops gred_qdisc_ops = {
.next = NULL,
.cl_ops = NULL,
.id = "gred",
.priv_size = sizeof(struct gred_sched),
.enqueue = gred_enqueue,
.dequeue = gred_dequeue,
.requeue = gred_requeue,
.drop = gred_drop,
.init = gred_init,
.reset = gred_reset,
.destroy = gred_destroy,
.change = gred_change,
.dump = gred_dump,
.owner = THIS_MODULE,
};
static int __init gred_module_init(void)
{
return register_qdisc(&gred_qdisc_ops);
}
static void __exit gred_module_exit(void)
{
unregister_qdisc(&gred_qdisc_ops);
}
module_init(gred_module_init)
module_exit(gred_module_exit)
MODULE_LICENSE("GPL");