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1/*
2 * net/sched/sch_red.c Random Early Detection queue.
3 *
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.
8 *
9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10 *
11 * Changes:
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
15 */
16
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>
23#include <net/red.h>
24
25
26/* Parameters, settable by user:
27 -----------------------------
28
29 limit - bytes (must be > qth_max + burst)
30
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.
37 */
38
39struct red_sched_data {
40 u32 limit; /* HARD maximal queue length */
41 unsigned char flags;
42 struct timer_list adapt_timer;
43 struct red_parms parms;
44 struct red_vars vars;
45 struct red_stats stats;
46 struct Qdisc *qdisc;
47};
48
49static inline int red_use_ecn(struct red_sched_data *q)
50{
51 return q->flags & TC_RED_ECN;
52}
53
54static inline int red_use_harddrop(struct red_sched_data *q)
55{
56 return q->flags & TC_RED_HARDDROP;
57}
58
59static int red_enqueue(struct sk_buff *skb, struct Qdisc *sch)
60{
61 struct red_sched_data *q = qdisc_priv(sch);
62 struct Qdisc *child = q->qdisc;
63 int ret;
64
65 q->vars.qavg = red_calc_qavg(&q->parms,
66 &q->vars,
67 child->qstats.backlog);
68
69 if (red_is_idling(&q->vars))
70 red_end_of_idle_period(&q->vars);
71
72 switch (red_action(&q->parms, &q->vars, q->vars.qavg)) {
73 case RED_DONT_MARK:
74 break;
75
76 case RED_PROB_MARK:
77 sch->qstats.overlimits++;
78 if (!red_use_ecn(q) || !INET_ECN_set_ce(skb)) {
79 q->stats.prob_drop++;
80 goto congestion_drop;
81 }
82
83 q->stats.prob_mark++;
84 break;
85
86 case RED_HARD_MARK:
87 sch->qstats.overlimits++;
88 if (red_use_harddrop(q) || !red_use_ecn(q) ||
89 !INET_ECN_set_ce(skb)) {
90 q->stats.forced_drop++;
91 goto congestion_drop;
92 }
93
94 q->stats.forced_mark++;
95 break;
96 }
97
98 ret = qdisc_enqueue(skb, child);
99 if (likely(ret == NET_XMIT_SUCCESS)) {
100 sch->q.qlen++;
101 } else if (net_xmit_drop_count(ret)) {
102 q->stats.pdrop++;
103 sch->qstats.drops++;
104 }
105 return ret;
106
107congestion_drop:
108 qdisc_drop(skb, sch);
109 return NET_XMIT_CN;
110}
111
112static struct sk_buff *red_dequeue(struct Qdisc *sch)
113{
114 struct sk_buff *skb;
115 struct red_sched_data *q = qdisc_priv(sch);
116 struct Qdisc *child = q->qdisc;
117
118 skb = child->dequeue(child);
119 if (skb) {
120 qdisc_bstats_update(sch, skb);
121 sch->q.qlen--;
122 } else {
123 if (!red_is_idling(&q->vars))
124 red_start_of_idle_period(&q->vars);
125 }
126 return skb;
127}
128
129static struct sk_buff *red_peek(struct Qdisc *sch)
130{
131 struct red_sched_data *q = qdisc_priv(sch);
132 struct Qdisc *child = q->qdisc;
133
134 return child->ops->peek(child);
135}
136
137static unsigned int red_drop(struct Qdisc *sch)
138{
139 struct red_sched_data *q = qdisc_priv(sch);
140 struct Qdisc *child = q->qdisc;
141 unsigned int len;
142
143 if (child->ops->drop && (len = child->ops->drop(child)) > 0) {
144 q->stats.other++;
145 sch->qstats.drops++;
146 sch->q.qlen--;
147 return len;
148 }
149
150 if (!red_is_idling(&q->vars))
151 red_start_of_idle_period(&q->vars);
152
153 return 0;
154}
155
156static void red_reset(struct Qdisc *sch)
157{
158 struct red_sched_data *q = qdisc_priv(sch);
159
160 qdisc_reset(q->qdisc);
161 sch->q.qlen = 0;
162 red_restart(&q->vars);
163}
164
165static void red_destroy(struct Qdisc *sch)
166{
167 struct red_sched_data *q = qdisc_priv(sch);
168
169 del_timer_sync(&q->adapt_timer);
170 qdisc_destroy(q->qdisc);
171}
172
173static const struct nla_policy red_policy[TCA_RED_MAX + 1] = {
174 [TCA_RED_PARMS] = { .len = sizeof(struct tc_red_qopt) },
175 [TCA_RED_STAB] = { .len = RED_STAB_SIZE },
176 [TCA_RED_MAX_P] = { .type = NLA_U32 },
177};
178
179static int red_change(struct Qdisc *sch, struct nlattr *opt)
180{
181 struct red_sched_data *q = qdisc_priv(sch);
182 struct nlattr *tb[TCA_RED_MAX + 1];
183 struct tc_red_qopt *ctl;
184 struct Qdisc *child = NULL;
185 int err;
186 u32 max_P;
187
188 if (opt == NULL)
189 return -EINVAL;
190
191 err = nla_parse_nested(tb, TCA_RED_MAX, opt, red_policy);
192 if (err < 0)
193 return err;
194
195 if (tb[TCA_RED_PARMS] == NULL ||
196 tb[TCA_RED_STAB] == NULL)
197 return -EINVAL;
198
199 max_P = tb[TCA_RED_MAX_P] ? nla_get_u32(tb[TCA_RED_MAX_P]) : 0;
200
201 ctl = nla_data(tb[TCA_RED_PARMS]);
202
203 if (ctl->limit > 0) {
204 child = fifo_create_dflt(sch, &bfifo_qdisc_ops, ctl->limit);
205 if (IS_ERR(child))
206 return PTR_ERR(child);
207 }
208
209 sch_tree_lock(sch);
210 q->flags = ctl->flags;
211 q->limit = ctl->limit;
212 if (child) {
213 qdisc_tree_decrease_qlen(q->qdisc, q->qdisc->q.qlen);
214 qdisc_destroy(q->qdisc);
215 q->qdisc = child;
216 }
217
218 red_set_parms(&q->parms,
219 ctl->qth_min, ctl->qth_max, ctl->Wlog,
220 ctl->Plog, ctl->Scell_log,
221 nla_data(tb[TCA_RED_STAB]),
222 max_P);
223 red_set_vars(&q->vars);
224
225 del_timer(&q->adapt_timer);
226 if (ctl->flags & TC_RED_ADAPTATIVE)
227 mod_timer(&q->adapt_timer, jiffies + HZ/2);
228
229 if (!q->qdisc->q.qlen)
230 red_start_of_idle_period(&q->vars);
231
232 sch_tree_unlock(sch);
233 return 0;
234}
235
236static inline void red_adaptative_timer(unsigned long arg)
237{
238 struct Qdisc *sch = (struct Qdisc *)arg;
239 struct red_sched_data *q = qdisc_priv(sch);
240 spinlock_t *root_lock = qdisc_lock(qdisc_root_sleeping(sch));
241
242 spin_lock(root_lock);
243 red_adaptative_algo(&q->parms, &q->vars);
244 mod_timer(&q->adapt_timer, jiffies + HZ/2);
245 spin_unlock(root_lock);
246}
247
248static int red_init(struct Qdisc *sch, struct nlattr *opt)
249{
250 struct red_sched_data *q = qdisc_priv(sch);
251
252 q->qdisc = &noop_qdisc;
253 setup_timer(&q->adapt_timer, red_adaptative_timer, (unsigned long)sch);
254 return red_change(sch, opt);
255}
256
257static int red_dump(struct Qdisc *sch, struct sk_buff *skb)
258{
259 struct red_sched_data *q = qdisc_priv(sch);
260 struct nlattr *opts = NULL;
261 struct tc_red_qopt opt = {
262 .limit = q->limit,
263 .flags = q->flags,
264 .qth_min = q->parms.qth_min >> q->parms.Wlog,
265 .qth_max = q->parms.qth_max >> q->parms.Wlog,
266 .Wlog = q->parms.Wlog,
267 .Plog = q->parms.Plog,
268 .Scell_log = q->parms.Scell_log,
269 };
270
271 sch->qstats.backlog = q->qdisc->qstats.backlog;
272 opts = nla_nest_start(skb, TCA_OPTIONS);
273 if (opts == NULL)
274 goto nla_put_failure;
275 if (nla_put(skb, TCA_RED_PARMS, sizeof(opt), &opt) ||
276 nla_put_u32(skb, TCA_RED_MAX_P, q->parms.max_P))
277 goto nla_put_failure;
278 return nla_nest_end(skb, opts);
279
280nla_put_failure:
281 nla_nest_cancel(skb, opts);
282 return -EMSGSIZE;
283}
284
285static int red_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
286{
287 struct red_sched_data *q = qdisc_priv(sch);
288 struct tc_red_xstats st = {
289 .early = q->stats.prob_drop + q->stats.forced_drop,
290 .pdrop = q->stats.pdrop,
291 .other = q->stats.other,
292 .marked = q->stats.prob_mark + q->stats.forced_mark,
293 };
294
295 return gnet_stats_copy_app(d, &st, sizeof(st));
296}
297
298static int red_dump_class(struct Qdisc *sch, unsigned long cl,
299 struct sk_buff *skb, struct tcmsg *tcm)
300{
301 struct red_sched_data *q = qdisc_priv(sch);
302
303 tcm->tcm_handle |= TC_H_MIN(1);
304 tcm->tcm_info = q->qdisc->handle;
305 return 0;
306}
307
308static int red_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
309 struct Qdisc **old)
310{
311 struct red_sched_data *q = qdisc_priv(sch);
312
313 if (new == NULL)
314 new = &noop_qdisc;
315
316 sch_tree_lock(sch);
317 *old = q->qdisc;
318 q->qdisc = new;
319 qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
320 qdisc_reset(*old);
321 sch_tree_unlock(sch);
322 return 0;
323}
324
325static struct Qdisc *red_leaf(struct Qdisc *sch, unsigned long arg)
326{
327 struct red_sched_data *q = qdisc_priv(sch);
328 return q->qdisc;
329}
330
331static unsigned long red_get(struct Qdisc *sch, u32 classid)
332{
333 return 1;
334}
335
336static void red_put(struct Qdisc *sch, unsigned long arg)
337{
338}
339
340static void red_walk(struct Qdisc *sch, struct qdisc_walker *walker)
341{
342 if (!walker->stop) {
343 if (walker->count >= walker->skip)
344 if (walker->fn(sch, 1, walker) < 0) {
345 walker->stop = 1;
346 return;
347 }
348 walker->count++;
349 }
350}
351
352static const struct Qdisc_class_ops red_class_ops = {
353 .graft = red_graft,
354 .leaf = red_leaf,
355 .get = red_get,
356 .put = red_put,
357 .walk = red_walk,
358 .dump = red_dump_class,
359};
360
361static struct Qdisc_ops red_qdisc_ops __read_mostly = {
362 .id = "red",
363 .priv_size = sizeof(struct red_sched_data),
364 .cl_ops = &red_class_ops,
365 .enqueue = red_enqueue,
366 .dequeue = red_dequeue,
367 .peek = red_peek,
368 .drop = red_drop,
369 .init = red_init,
370 .reset = red_reset,
371 .destroy = red_destroy,
372 .change = red_change,
373 .dump = red_dump,
374 .dump_stats = red_dump_stats,
375 .owner = THIS_MODULE,
376};
377
378static int __init red_module_init(void)
379{
380 return register_qdisc(&red_qdisc_ops);
381}
382
383static void __exit red_module_exit(void)
384{
385 unregister_qdisc(&red_qdisc_ops);
386}
387
388module_init(red_module_init)
389module_exit(red_module_exit)
390
391MODULE_LICENSE("GPL");
1/*
2 * net/sched/sch_red.c Random Early Detection queue.
3 *
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.
8 *
9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10 *
11 * Changes:
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
15 */
16
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>
23#include <net/red.h>
24
25
26/* Parameters, settable by user:
27 -----------------------------
28
29 limit - bytes (must be > qth_max + burst)
30
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.
37 */
38
39struct red_sched_data {
40 u32 limit; /* HARD maximal queue length */
41 unsigned char flags;
42 struct red_parms parms;
43 struct red_stats stats;
44 struct Qdisc *qdisc;
45};
46
47static inline int red_use_ecn(struct red_sched_data *q)
48{
49 return q->flags & TC_RED_ECN;
50}
51
52static inline int red_use_harddrop(struct red_sched_data *q)
53{
54 return q->flags & TC_RED_HARDDROP;
55}
56
57static int red_enqueue(struct sk_buff *skb, struct Qdisc *sch)
58{
59 struct red_sched_data *q = qdisc_priv(sch);
60 struct Qdisc *child = q->qdisc;
61 int ret;
62
63 q->parms.qavg = red_calc_qavg(&q->parms, child->qstats.backlog);
64
65 if (red_is_idling(&q->parms))
66 red_end_of_idle_period(&q->parms);
67
68 switch (red_action(&q->parms, q->parms.qavg)) {
69 case RED_DONT_MARK:
70 break;
71
72 case RED_PROB_MARK:
73 sch->qstats.overlimits++;
74 if (!red_use_ecn(q) || !INET_ECN_set_ce(skb)) {
75 q->stats.prob_drop++;
76 goto congestion_drop;
77 }
78
79 q->stats.prob_mark++;
80 break;
81
82 case RED_HARD_MARK:
83 sch->qstats.overlimits++;
84 if (red_use_harddrop(q) || !red_use_ecn(q) ||
85 !INET_ECN_set_ce(skb)) {
86 q->stats.forced_drop++;
87 goto congestion_drop;
88 }
89
90 q->stats.forced_mark++;
91 break;
92 }
93
94 ret = qdisc_enqueue(skb, child);
95 if (likely(ret == NET_XMIT_SUCCESS)) {
96 sch->q.qlen++;
97 } else if (net_xmit_drop_count(ret)) {
98 q->stats.pdrop++;
99 sch->qstats.drops++;
100 }
101 return ret;
102
103congestion_drop:
104 qdisc_drop(skb, sch);
105 return NET_XMIT_CN;
106}
107
108static struct sk_buff *red_dequeue(struct Qdisc *sch)
109{
110 struct sk_buff *skb;
111 struct red_sched_data *q = qdisc_priv(sch);
112 struct Qdisc *child = q->qdisc;
113
114 skb = child->dequeue(child);
115 if (skb) {
116 qdisc_bstats_update(sch, skb);
117 sch->q.qlen--;
118 } else {
119 if (!red_is_idling(&q->parms))
120 red_start_of_idle_period(&q->parms);
121 }
122 return skb;
123}
124
125static struct sk_buff *red_peek(struct Qdisc *sch)
126{
127 struct red_sched_data *q = qdisc_priv(sch);
128 struct Qdisc *child = q->qdisc;
129
130 return child->ops->peek(child);
131}
132
133static unsigned int red_drop(struct Qdisc *sch)
134{
135 struct red_sched_data *q = qdisc_priv(sch);
136 struct Qdisc *child = q->qdisc;
137 unsigned int len;
138
139 if (child->ops->drop && (len = child->ops->drop(child)) > 0) {
140 q->stats.other++;
141 sch->qstats.drops++;
142 sch->q.qlen--;
143 return len;
144 }
145
146 if (!red_is_idling(&q->parms))
147 red_start_of_idle_period(&q->parms);
148
149 return 0;
150}
151
152static void red_reset(struct Qdisc *sch)
153{
154 struct red_sched_data *q = qdisc_priv(sch);
155
156 qdisc_reset(q->qdisc);
157 sch->q.qlen = 0;
158 red_restart(&q->parms);
159}
160
161static void red_destroy(struct Qdisc *sch)
162{
163 struct red_sched_data *q = qdisc_priv(sch);
164 qdisc_destroy(q->qdisc);
165}
166
167static const struct nla_policy red_policy[TCA_RED_MAX + 1] = {
168 [TCA_RED_PARMS] = { .len = sizeof(struct tc_red_qopt) },
169 [TCA_RED_STAB] = { .len = RED_STAB_SIZE },
170};
171
172static int red_change(struct Qdisc *sch, struct nlattr *opt)
173{
174 struct red_sched_data *q = qdisc_priv(sch);
175 struct nlattr *tb[TCA_RED_MAX + 1];
176 struct tc_red_qopt *ctl;
177 struct Qdisc *child = NULL;
178 int err;
179
180 if (opt == NULL)
181 return -EINVAL;
182
183 err = nla_parse_nested(tb, TCA_RED_MAX, opt, red_policy);
184 if (err < 0)
185 return err;
186
187 if (tb[TCA_RED_PARMS] == NULL ||
188 tb[TCA_RED_STAB] == NULL)
189 return -EINVAL;
190
191 ctl = nla_data(tb[TCA_RED_PARMS]);
192
193 if (ctl->limit > 0) {
194 child = fifo_create_dflt(sch, &bfifo_qdisc_ops, ctl->limit);
195 if (IS_ERR(child))
196 return PTR_ERR(child);
197 }
198
199 sch_tree_lock(sch);
200 q->flags = ctl->flags;
201 q->limit = ctl->limit;
202 if (child) {
203 qdisc_tree_decrease_qlen(q->qdisc, q->qdisc->q.qlen);
204 qdisc_destroy(q->qdisc);
205 q->qdisc = child;
206 }
207
208 red_set_parms(&q->parms, ctl->qth_min, ctl->qth_max, ctl->Wlog,
209 ctl->Plog, ctl->Scell_log,
210 nla_data(tb[TCA_RED_STAB]));
211
212 if (skb_queue_empty(&sch->q))
213 red_end_of_idle_period(&q->parms);
214
215 sch_tree_unlock(sch);
216 return 0;
217}
218
219static int red_init(struct Qdisc *sch, struct nlattr *opt)
220{
221 struct red_sched_data *q = qdisc_priv(sch);
222
223 q->qdisc = &noop_qdisc;
224 return red_change(sch, opt);
225}
226
227static int red_dump(struct Qdisc *sch, struct sk_buff *skb)
228{
229 struct red_sched_data *q = qdisc_priv(sch);
230 struct nlattr *opts = NULL;
231 struct tc_red_qopt opt = {
232 .limit = q->limit,
233 .flags = q->flags,
234 .qth_min = q->parms.qth_min >> q->parms.Wlog,
235 .qth_max = q->parms.qth_max >> q->parms.Wlog,
236 .Wlog = q->parms.Wlog,
237 .Plog = q->parms.Plog,
238 .Scell_log = q->parms.Scell_log,
239 };
240
241 sch->qstats.backlog = q->qdisc->qstats.backlog;
242 opts = nla_nest_start(skb, TCA_OPTIONS);
243 if (opts == NULL)
244 goto nla_put_failure;
245 NLA_PUT(skb, TCA_RED_PARMS, sizeof(opt), &opt);
246 return nla_nest_end(skb, opts);
247
248nla_put_failure:
249 nla_nest_cancel(skb, opts);
250 return -EMSGSIZE;
251}
252
253static int red_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
254{
255 struct red_sched_data *q = qdisc_priv(sch);
256 struct tc_red_xstats st = {
257 .early = q->stats.prob_drop + q->stats.forced_drop,
258 .pdrop = q->stats.pdrop,
259 .other = q->stats.other,
260 .marked = q->stats.prob_mark + q->stats.forced_mark,
261 };
262
263 return gnet_stats_copy_app(d, &st, sizeof(st));
264}
265
266static int red_dump_class(struct Qdisc *sch, unsigned long cl,
267 struct sk_buff *skb, struct tcmsg *tcm)
268{
269 struct red_sched_data *q = qdisc_priv(sch);
270
271 tcm->tcm_handle |= TC_H_MIN(1);
272 tcm->tcm_info = q->qdisc->handle;
273 return 0;
274}
275
276static int red_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
277 struct Qdisc **old)
278{
279 struct red_sched_data *q = qdisc_priv(sch);
280
281 if (new == NULL)
282 new = &noop_qdisc;
283
284 sch_tree_lock(sch);
285 *old = q->qdisc;
286 q->qdisc = new;
287 qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
288 qdisc_reset(*old);
289 sch_tree_unlock(sch);
290 return 0;
291}
292
293static struct Qdisc *red_leaf(struct Qdisc *sch, unsigned long arg)
294{
295 struct red_sched_data *q = qdisc_priv(sch);
296 return q->qdisc;
297}
298
299static unsigned long red_get(struct Qdisc *sch, u32 classid)
300{
301 return 1;
302}
303
304static void red_put(struct Qdisc *sch, unsigned long arg)
305{
306}
307
308static void red_walk(struct Qdisc *sch, struct qdisc_walker *walker)
309{
310 if (!walker->stop) {
311 if (walker->count >= walker->skip)
312 if (walker->fn(sch, 1, walker) < 0) {
313 walker->stop = 1;
314 return;
315 }
316 walker->count++;
317 }
318}
319
320static const struct Qdisc_class_ops red_class_ops = {
321 .graft = red_graft,
322 .leaf = red_leaf,
323 .get = red_get,
324 .put = red_put,
325 .walk = red_walk,
326 .dump = red_dump_class,
327};
328
329static struct Qdisc_ops red_qdisc_ops __read_mostly = {
330 .id = "red",
331 .priv_size = sizeof(struct red_sched_data),
332 .cl_ops = &red_class_ops,
333 .enqueue = red_enqueue,
334 .dequeue = red_dequeue,
335 .peek = red_peek,
336 .drop = red_drop,
337 .init = red_init,
338 .reset = red_reset,
339 .destroy = red_destroy,
340 .change = red_change,
341 .dump = red_dump,
342 .dump_stats = red_dump_stats,
343 .owner = THIS_MODULE,
344};
345
346static int __init red_module_init(void)
347{
348 return register_qdisc(&red_qdisc_ops);
349}
350
351static void __exit red_module_exit(void)
352{
353 unregister_qdisc(&red_qdisc_ops);
354}
355
356module_init(red_module_init)
357module_exit(red_module_exit)
358
359MODULE_LICENSE("GPL");