2 * net/sched/sch_red.c Random Early Detection queue.
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, or (at your option) any later version.
9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
12 * J Hadi Salim 980914: computation fixes
13 * Alexey Makarenko <makar@phoenix.kharkov.ua> 990814: qave on idle link was calculated incorrectly.
14 * J Hadi Salim 980816: ECN support
17 #include <linux/module.h>
18 #include <linux/types.h>
19 #include <linux/kernel.h>
20 #include <linux/skbuff.h>
21 #include <net/pkt_sched.h>
22 #include <net/inet_ecn.h>
26 /* Parameters, settable by user:
27 -----------------------------
29 limit - bytes (must be > qth_max + burst)
31 Hard limit on queue length, should be chosen >qth_max
32 to allow packet bursts. This parameter does not
33 affect the algorithms behaviour and can be chosen
34 arbitrarily high (well, less than ram size)
35 Really, this limit will never be reached
36 if RED works correctly.
39 struct red_sched_data
{
40 u32 limit
; /* HARD maximal queue length */
42 struct timer_list adapt_timer
;
43 struct red_parms parms
;
45 struct red_stats stats
;
49 static inline int red_use_ecn(struct red_sched_data
*q
)
51 return q
->flags
& TC_RED_ECN
;
54 static inline int red_use_harddrop(struct red_sched_data
*q
)
56 return q
->flags
& TC_RED_HARDDROP
;
59 static int red_enqueue(struct sk_buff
*skb
, struct Qdisc
*sch
,
60 struct sk_buff
**to_free
)
62 struct red_sched_data
*q
= qdisc_priv(sch
);
63 struct Qdisc
*child
= q
->qdisc
;
66 q
->vars
.qavg
= red_calc_qavg(&q
->parms
,
68 child
->qstats
.backlog
);
70 if (red_is_idling(&q
->vars
))
71 red_end_of_idle_period(&q
->vars
);
73 switch (red_action(&q
->parms
, &q
->vars
, q
->vars
.qavg
)) {
78 qdisc_qstats_overlimit(sch
);
79 if (!red_use_ecn(q
) || !INET_ECN_set_ce(skb
)) {
88 qdisc_qstats_overlimit(sch
);
89 if (red_use_harddrop(q
) || !red_use_ecn(q
) ||
90 !INET_ECN_set_ce(skb
)) {
91 q
->stats
.forced_drop
++;
95 q
->stats
.forced_mark
++;
99 ret
= qdisc_enqueue(skb
, child
, to_free
);
100 if (likely(ret
== NET_XMIT_SUCCESS
)) {
101 qdisc_qstats_backlog_inc(sch
, skb
);
103 } else if (net_xmit_drop_count(ret
)) {
105 qdisc_qstats_drop(sch
);
110 qdisc_drop(skb
, sch
, to_free
);
114 static struct sk_buff
*red_dequeue(struct Qdisc
*sch
)
117 struct red_sched_data
*q
= qdisc_priv(sch
);
118 struct Qdisc
*child
= q
->qdisc
;
120 skb
= child
->dequeue(child
);
122 qdisc_bstats_update(sch
, skb
);
123 qdisc_qstats_backlog_dec(sch
, skb
);
126 if (!red_is_idling(&q
->vars
))
127 red_start_of_idle_period(&q
->vars
);
132 static struct sk_buff
*red_peek(struct Qdisc
*sch
)
134 struct red_sched_data
*q
= qdisc_priv(sch
);
135 struct Qdisc
*child
= q
->qdisc
;
137 return child
->ops
->peek(child
);
140 static void red_reset(struct Qdisc
*sch
)
142 struct red_sched_data
*q
= qdisc_priv(sch
);
144 qdisc_reset(q
->qdisc
);
145 sch
->qstats
.backlog
= 0;
147 red_restart(&q
->vars
);
150 static void red_destroy(struct Qdisc
*sch
)
152 struct red_sched_data
*q
= qdisc_priv(sch
);
154 del_timer_sync(&q
->adapt_timer
);
155 qdisc_destroy(q
->qdisc
);
158 static const struct nla_policy red_policy
[TCA_RED_MAX
+ 1] = {
159 [TCA_RED_PARMS
] = { .len
= sizeof(struct tc_red_qopt
) },
160 [TCA_RED_STAB
] = { .len
= RED_STAB_SIZE
},
161 [TCA_RED_MAX_P
] = { .type
= NLA_U32
},
164 static int red_change(struct Qdisc
*sch
, struct nlattr
*opt
)
166 struct red_sched_data
*q
= qdisc_priv(sch
);
167 struct nlattr
*tb
[TCA_RED_MAX
+ 1];
168 struct tc_red_qopt
*ctl
;
169 struct Qdisc
*child
= NULL
;
176 err
= nla_parse_nested(tb
, TCA_RED_MAX
, opt
, red_policy
, NULL
);
180 if (tb
[TCA_RED_PARMS
] == NULL
||
181 tb
[TCA_RED_STAB
] == NULL
)
184 max_P
= tb
[TCA_RED_MAX_P
] ? nla_get_u32(tb
[TCA_RED_MAX_P
]) : 0;
186 ctl
= nla_data(tb
[TCA_RED_PARMS
]);
188 if (ctl
->limit
> 0) {
189 child
= fifo_create_dflt(sch
, &bfifo_qdisc_ops
, ctl
->limit
);
191 return PTR_ERR(child
);
194 if (child
!= &noop_qdisc
)
195 qdisc_hash_add(child
, true);
197 q
->flags
= ctl
->flags
;
198 q
->limit
= ctl
->limit
;
200 qdisc_tree_reduce_backlog(q
->qdisc
, q
->qdisc
->q
.qlen
,
201 q
->qdisc
->qstats
.backlog
);
202 qdisc_destroy(q
->qdisc
);
206 red_set_parms(&q
->parms
,
207 ctl
->qth_min
, ctl
->qth_max
, ctl
->Wlog
,
208 ctl
->Plog
, ctl
->Scell_log
,
209 nla_data(tb
[TCA_RED_STAB
]),
211 red_set_vars(&q
->vars
);
213 del_timer(&q
->adapt_timer
);
214 if (ctl
->flags
& TC_RED_ADAPTATIVE
)
215 mod_timer(&q
->adapt_timer
, jiffies
+ HZ
/2);
217 if (!q
->qdisc
->q
.qlen
)
218 red_start_of_idle_period(&q
->vars
);
220 sch_tree_unlock(sch
);
224 static inline void red_adaptative_timer(unsigned long arg
)
226 struct Qdisc
*sch
= (struct Qdisc
*)arg
;
227 struct red_sched_data
*q
= qdisc_priv(sch
);
228 spinlock_t
*root_lock
= qdisc_lock(qdisc_root_sleeping(sch
));
230 spin_lock(root_lock
);
231 red_adaptative_algo(&q
->parms
, &q
->vars
);
232 mod_timer(&q
->adapt_timer
, jiffies
+ HZ
/2);
233 spin_unlock(root_lock
);
236 static int red_init(struct Qdisc
*sch
, struct nlattr
*opt
)
238 struct red_sched_data
*q
= qdisc_priv(sch
);
240 q
->qdisc
= &noop_qdisc
;
241 setup_timer(&q
->adapt_timer
, red_adaptative_timer
, (unsigned long)sch
);
242 return red_change(sch
, opt
);
245 static int red_dump(struct Qdisc
*sch
, struct sk_buff
*skb
)
247 struct red_sched_data
*q
= qdisc_priv(sch
);
248 struct nlattr
*opts
= NULL
;
249 struct tc_red_qopt opt
= {
252 .qth_min
= q
->parms
.qth_min
>> q
->parms
.Wlog
,
253 .qth_max
= q
->parms
.qth_max
>> q
->parms
.Wlog
,
254 .Wlog
= q
->parms
.Wlog
,
255 .Plog
= q
->parms
.Plog
,
256 .Scell_log
= q
->parms
.Scell_log
,
259 sch
->qstats
.backlog
= q
->qdisc
->qstats
.backlog
;
260 opts
= nla_nest_start(skb
, TCA_OPTIONS
);
262 goto nla_put_failure
;
263 if (nla_put(skb
, TCA_RED_PARMS
, sizeof(opt
), &opt
) ||
264 nla_put_u32(skb
, TCA_RED_MAX_P
, q
->parms
.max_P
))
265 goto nla_put_failure
;
266 return nla_nest_end(skb
, opts
);
269 nla_nest_cancel(skb
, opts
);
273 static int red_dump_stats(struct Qdisc
*sch
, struct gnet_dump
*d
)
275 struct red_sched_data
*q
= qdisc_priv(sch
);
276 struct tc_red_xstats st
= {
277 .early
= q
->stats
.prob_drop
+ q
->stats
.forced_drop
,
278 .pdrop
= q
->stats
.pdrop
,
279 .other
= q
->stats
.other
,
280 .marked
= q
->stats
.prob_mark
+ q
->stats
.forced_mark
,
283 return gnet_stats_copy_app(d
, &st
, sizeof(st
));
286 static int red_dump_class(struct Qdisc
*sch
, unsigned long cl
,
287 struct sk_buff
*skb
, struct tcmsg
*tcm
)
289 struct red_sched_data
*q
= qdisc_priv(sch
);
291 tcm
->tcm_handle
|= TC_H_MIN(1);
292 tcm
->tcm_info
= q
->qdisc
->handle
;
296 static int red_graft(struct Qdisc
*sch
, unsigned long arg
, struct Qdisc
*new,
299 struct red_sched_data
*q
= qdisc_priv(sch
);
304 *old
= qdisc_replace(sch
, new, &q
->qdisc
);
308 static struct Qdisc
*red_leaf(struct Qdisc
*sch
, unsigned long arg
)
310 struct red_sched_data
*q
= qdisc_priv(sch
);
314 static unsigned long red_get(struct Qdisc
*sch
, u32 classid
)
319 static void red_put(struct Qdisc
*sch
, unsigned long arg
)
323 static void red_walk(struct Qdisc
*sch
, struct qdisc_walker
*walker
)
326 if (walker
->count
>= walker
->skip
)
327 if (walker
->fn(sch
, 1, walker
) < 0) {
335 static const struct Qdisc_class_ops red_class_ops
= {
341 .dump
= red_dump_class
,
344 static struct Qdisc_ops red_qdisc_ops __read_mostly
= {
346 .priv_size
= sizeof(struct red_sched_data
),
347 .cl_ops
= &red_class_ops
,
348 .enqueue
= red_enqueue
,
349 .dequeue
= red_dequeue
,
353 .destroy
= red_destroy
,
354 .change
= red_change
,
356 .dump_stats
= red_dump_stats
,
357 .owner
= THIS_MODULE
,
360 static int __init
red_module_init(void)
362 return register_qdisc(&red_qdisc_ops
);
365 static void __exit
red_module_exit(void)
367 unregister_qdisc(&red_qdisc_ops
);
370 module_init(red_module_init
)
371 module_exit(red_module_exit
)
373 MODULE_LICENSE("GPL");