Skip to content
Permalink
Branch: master
Find file Copy path
Find file Copy path
Fetching contributors…
Cannot retrieve contributors at this time
457 lines (380 sloc) 10.5 KB
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* net/sched/sch_red.c Random Early Detection queue.
*
* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
*
* Changes:
* J Hadi Salim 980914: computation fixes
* Alexey Makarenko <makar@phoenix.kharkov.ua> 990814: qave on idle link was calculated incorrectly.
* J Hadi Salim 980816: ECN support
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <net/pkt_sched.h>
#include <net/pkt_cls.h>
#include <net/inet_ecn.h>
#include <net/red.h>
/* Parameters, settable by user:
-----------------------------
limit - bytes (must be > qth_max + burst)
Hard limit on queue length, should be chosen >qth_max
to allow packet bursts. This parameter does not
affect the algorithms behaviour and can be chosen
arbitrarily high (well, less than ram size)
Really, this limit will never be reached
if RED works correctly.
*/
struct red_sched_data {
u32 limit; /* HARD maximal queue length */
unsigned char flags;
struct timer_list adapt_timer;
struct Qdisc *sch;
struct red_parms parms;
struct red_vars vars;
struct red_stats stats;
struct Qdisc *qdisc;
};
static inline int red_use_ecn(struct red_sched_data *q)
{
return q->flags & TC_RED_ECN;
}
static inline int red_use_harddrop(struct red_sched_data *q)
{
return q->flags & TC_RED_HARDDROP;
}
static int red_enqueue(struct sk_buff *skb, struct Qdisc *sch,
struct sk_buff **to_free)
{
struct red_sched_data *q = qdisc_priv(sch);
struct Qdisc *child = q->qdisc;
int ret;
q->vars.qavg = red_calc_qavg(&q->parms,
&q->vars,
child->qstats.backlog);
if (red_is_idling(&q->vars))
red_end_of_idle_period(&q->vars);
switch (red_action(&q->parms, &q->vars, q->vars.qavg)) {
case RED_DONT_MARK:
break;
case RED_PROB_MARK:
qdisc_qstats_overlimit(sch);
if (!red_use_ecn(q) || !INET_ECN_set_ce(skb)) {
q->stats.prob_drop++;
goto congestion_drop;
}
q->stats.prob_mark++;
break;
case RED_HARD_MARK:
qdisc_qstats_overlimit(sch);
if (red_use_harddrop(q) || !red_use_ecn(q) ||
!INET_ECN_set_ce(skb)) {
q->stats.forced_drop++;
goto congestion_drop;
}
q->stats.forced_mark++;
break;
}
ret = qdisc_enqueue(skb, child, to_free);
if (likely(ret == NET_XMIT_SUCCESS)) {
qdisc_qstats_backlog_inc(sch, skb);
sch->q.qlen++;
} else if (net_xmit_drop_count(ret)) {
q->stats.pdrop++;
qdisc_qstats_drop(sch);
}
return ret;
congestion_drop:
qdisc_drop(skb, sch, to_free);
return NET_XMIT_CN;
}
static struct sk_buff *red_dequeue(struct Qdisc *sch)
{
struct sk_buff *skb;
struct red_sched_data *q = qdisc_priv(sch);
struct Qdisc *child = q->qdisc;
skb = child->dequeue(child);
if (skb) {
qdisc_bstats_update(sch, skb);
qdisc_qstats_backlog_dec(sch, skb);
sch->q.qlen--;
} else {
if (!red_is_idling(&q->vars))
red_start_of_idle_period(&q->vars);
}
return skb;
}
static struct sk_buff *red_peek(struct Qdisc *sch)
{
struct red_sched_data *q = qdisc_priv(sch);
struct Qdisc *child = q->qdisc;
return child->ops->peek(child);
}
static void red_reset(struct Qdisc *sch)
{
struct red_sched_data *q = qdisc_priv(sch);
qdisc_reset(q->qdisc);
sch->qstats.backlog = 0;
sch->q.qlen = 0;
red_restart(&q->vars);
}
static int red_offload(struct Qdisc *sch, bool enable)
{
struct red_sched_data *q = qdisc_priv(sch);
struct net_device *dev = qdisc_dev(sch);
struct tc_red_qopt_offload opt = {
.handle = sch->handle,
.parent = sch->parent,
};
if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
return -EOPNOTSUPP;
if (enable) {
opt.command = TC_RED_REPLACE;
opt.set.min = q->parms.qth_min >> q->parms.Wlog;
opt.set.max = q->parms.qth_max >> q->parms.Wlog;
opt.set.probability = q->parms.max_P;
opt.set.limit = q->limit;
opt.set.is_ecn = red_use_ecn(q);
opt.set.is_harddrop = red_use_harddrop(q);
opt.set.qstats = &sch->qstats;
} else {
opt.command = TC_RED_DESTROY;
}
return dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_RED, &opt);
}
static void red_destroy(struct Qdisc *sch)
{
struct red_sched_data *q = qdisc_priv(sch);
del_timer_sync(&q->adapt_timer);
red_offload(sch, false);
qdisc_put(q->qdisc);
}
static const struct nla_policy red_policy[TCA_RED_MAX + 1] = {
[TCA_RED_PARMS] = { .len = sizeof(struct tc_red_qopt) },
[TCA_RED_STAB] = { .len = RED_STAB_SIZE },
[TCA_RED_MAX_P] = { .type = NLA_U32 },
};
static int red_change(struct Qdisc *sch, struct nlattr *opt,
struct netlink_ext_ack *extack)
{
struct Qdisc *old_child = NULL, *child = NULL;
struct red_sched_data *q = qdisc_priv(sch);
struct nlattr *tb[TCA_RED_MAX + 1];
struct tc_red_qopt *ctl;
int err;
u32 max_P;
if (opt == NULL)
return -EINVAL;
err = nla_parse_nested_deprecated(tb, TCA_RED_MAX, opt, red_policy,
NULL);
if (err < 0)
return err;
if (tb[TCA_RED_PARMS] == NULL ||
tb[TCA_RED_STAB] == NULL)
return -EINVAL;
max_P = tb[TCA_RED_MAX_P] ? nla_get_u32(tb[TCA_RED_MAX_P]) : 0;
ctl = nla_data(tb[TCA_RED_PARMS]);
if (!red_check_params(ctl->qth_min, ctl->qth_max, ctl->Wlog))
return -EINVAL;
if (ctl->limit > 0) {
child = fifo_create_dflt(sch, &bfifo_qdisc_ops, ctl->limit,
extack);
if (IS_ERR(child))
return PTR_ERR(child);
/* child is fifo, no need to check for noop_qdisc */
qdisc_hash_add(child, true);
}
sch_tree_lock(sch);
q->flags = ctl->flags;
q->limit = ctl->limit;
if (child) {
qdisc_tree_flush_backlog(q->qdisc);
old_child = q->qdisc;
q->qdisc = child;
}
red_set_parms(&q->parms,
ctl->qth_min, ctl->qth_max, ctl->Wlog,
ctl->Plog, ctl->Scell_log,
nla_data(tb[TCA_RED_STAB]),
max_P);
red_set_vars(&q->vars);
del_timer(&q->adapt_timer);
if (ctl->flags & TC_RED_ADAPTATIVE)
mod_timer(&q->adapt_timer, jiffies + HZ/2);
if (!q->qdisc->q.qlen)
red_start_of_idle_period(&q->vars);
sch_tree_unlock(sch);
red_offload(sch, true);
if (old_child)
qdisc_put(old_child);
return 0;
}
static inline void red_adaptative_timer(struct timer_list *t)
{
struct red_sched_data *q = from_timer(q, t, adapt_timer);
struct Qdisc *sch = q->sch;
spinlock_t *root_lock = qdisc_lock(qdisc_root_sleeping(sch));
spin_lock(root_lock);
red_adaptative_algo(&q->parms, &q->vars);
mod_timer(&q->adapt_timer, jiffies + HZ/2);
spin_unlock(root_lock);
}
static int red_init(struct Qdisc *sch, struct nlattr *opt,
struct netlink_ext_ack *extack)
{
struct red_sched_data *q = qdisc_priv(sch);
q->qdisc = &noop_qdisc;
q->sch = sch;
timer_setup(&q->adapt_timer, red_adaptative_timer, 0);
return red_change(sch, opt, extack);
}
static int red_dump_offload_stats(struct Qdisc *sch)
{
struct tc_red_qopt_offload hw_stats = {
.command = TC_RED_STATS,
.handle = sch->handle,
.parent = sch->parent,
{
.stats.bstats = &sch->bstats,
.stats.qstats = &sch->qstats,
},
};
return qdisc_offload_dump_helper(sch, TC_SETUP_QDISC_RED, &hw_stats);
}
static int red_dump(struct Qdisc *sch, struct sk_buff *skb)
{
struct red_sched_data *q = qdisc_priv(sch);
struct nlattr *opts = NULL;
struct tc_red_qopt opt = {
.limit = q->limit,
.flags = q->flags,
.qth_min = q->parms.qth_min >> q->parms.Wlog,
.qth_max = q->parms.qth_max >> q->parms.Wlog,
.Wlog = q->parms.Wlog,
.Plog = q->parms.Plog,
.Scell_log = q->parms.Scell_log,
};
int err;
err = red_dump_offload_stats(sch);
if (err)
goto nla_put_failure;
opts = nla_nest_start_noflag(skb, TCA_OPTIONS);
if (opts == NULL)
goto nla_put_failure;
if (nla_put(skb, TCA_RED_PARMS, sizeof(opt), &opt) ||
nla_put_u32(skb, TCA_RED_MAX_P, q->parms.max_P))
goto nla_put_failure;
return nla_nest_end(skb, opts);
nla_put_failure:
nla_nest_cancel(skb, opts);
return -EMSGSIZE;
}
static int red_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
{
struct red_sched_data *q = qdisc_priv(sch);
struct net_device *dev = qdisc_dev(sch);
struct tc_red_xstats st = {0};
if (sch->flags & TCQ_F_OFFLOADED) {
struct tc_red_qopt_offload hw_stats_request = {
.command = TC_RED_XSTATS,
.handle = sch->handle,
.parent = sch->parent,
{
.xstats = &q->stats,
},
};
dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_RED,
&hw_stats_request);
}
st.early = q->stats.prob_drop + q->stats.forced_drop;
st.pdrop = q->stats.pdrop;
st.other = q->stats.other;
st.marked = q->stats.prob_mark + q->stats.forced_mark;
return gnet_stats_copy_app(d, &st, sizeof(st));
}
static int red_dump_class(struct Qdisc *sch, unsigned long cl,
struct sk_buff *skb, struct tcmsg *tcm)
{
struct red_sched_data *q = qdisc_priv(sch);
tcm->tcm_handle |= TC_H_MIN(1);
tcm->tcm_info = q->qdisc->handle;
return 0;
}
static void red_graft_offload(struct Qdisc *sch,
struct Qdisc *new, struct Qdisc *old,
struct netlink_ext_ack *extack)
{
struct tc_red_qopt_offload graft_offload = {
.handle = sch->handle,
.parent = sch->parent,
.child_handle = new->handle,
.command = TC_RED_GRAFT,
};
qdisc_offload_graft_helper(qdisc_dev(sch), sch, new, old,
TC_SETUP_QDISC_RED, &graft_offload, extack);
}
static int red_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
struct Qdisc **old, struct netlink_ext_ack *extack)
{
struct red_sched_data *q = qdisc_priv(sch);
if (new == NULL)
new = &noop_qdisc;
*old = qdisc_replace(sch, new, &q->qdisc);
red_graft_offload(sch, new, *old, extack);
return 0;
}
static struct Qdisc *red_leaf(struct Qdisc *sch, unsigned long arg)
{
struct red_sched_data *q = qdisc_priv(sch);
return q->qdisc;
}
static unsigned long red_find(struct Qdisc *sch, u32 classid)
{
return 1;
}
static void red_walk(struct Qdisc *sch, struct qdisc_walker *walker)
{
if (!walker->stop) {
if (walker->count >= walker->skip)
if (walker->fn(sch, 1, walker) < 0) {
walker->stop = 1;
return;
}
walker->count++;
}
}
static const struct Qdisc_class_ops red_class_ops = {
.graft = red_graft,
.leaf = red_leaf,
.find = red_find,
.walk = red_walk,
.dump = red_dump_class,
};
static struct Qdisc_ops red_qdisc_ops __read_mostly = {
.id = "red",
.priv_size = sizeof(struct red_sched_data),
.cl_ops = &red_class_ops,
.enqueue = red_enqueue,
.dequeue = red_dequeue,
.peek = red_peek,
.init = red_init,
.reset = red_reset,
.destroy = red_destroy,
.change = red_change,
.dump = red_dump,
.dump_stats = red_dump_stats,
.owner = THIS_MODULE,
};
static int __init red_module_init(void)
{
return register_qdisc(&red_qdisc_ops);
}
static void __exit red_module_exit(void)
{
unregister_qdisc(&red_qdisc_ops);
}
module_init(red_module_init)
module_exit(red_module_exit)
MODULE_LICENSE("GPL");
You can’t perform that action at this time.