Commit | Line | Data |
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1da177e4 LT |
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: | |
dba051f3 | 12 | * J Hadi Salim 980914: computation fixes |
1da177e4 | 13 | * Alexey Makarenko <makar@phoenix.kharkov.ua> 990814: qave on idle link was calculated incorrectly. |
dba051f3 | 14 | * J Hadi Salim 980816: ECN support |
1da177e4 LT |
15 | */ |
16 | ||
1da177e4 | 17 | #include <linux/module.h> |
1da177e4 LT |
18 | #include <linux/types.h> |
19 | #include <linux/kernel.h> | |
1da177e4 | 20 | #include <linux/skbuff.h> |
1da177e4 LT |
21 | #include <net/pkt_sched.h> |
22 | #include <net/inet_ecn.h> | |
6b31b28a | 23 | #include <net/red.h> |
1da177e4 LT |
24 | |
25 | ||
6b31b28a | 26 | /* Parameters, settable by user: |
1da177e4 LT |
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. | |
1da177e4 LT |
37 | */ |
38 | ||
cc7ec456 | 39 | struct red_sched_data { |
6b31b28a TG |
40 | u32 limit; /* HARD maximal queue length */ |
41 | unsigned char flags; | |
8af2a218 | 42 | struct timer_list adapt_timer; |
6b31b28a | 43 | struct red_parms parms; |
eeca6688 | 44 | struct red_vars vars; |
6b31b28a | 45 | struct red_stats stats; |
f38c39d6 | 46 | struct Qdisc *qdisc; |
1da177e4 LT |
47 | }; |
48 | ||
6b31b28a | 49 | static inline int red_use_ecn(struct red_sched_data *q) |
1da177e4 | 50 | { |
6b31b28a | 51 | return q->flags & TC_RED_ECN; |
1da177e4 LT |
52 | } |
53 | ||
bdc450a0 TG |
54 | static inline int red_use_harddrop(struct red_sched_data *q) |
55 | { | |
56 | return q->flags & TC_RED_HARDDROP; | |
57 | } | |
58 | ||
cc7ec456 | 59 | static int red_enqueue(struct sk_buff *skb, struct Qdisc *sch) |
1da177e4 LT |
60 | { |
61 | struct red_sched_data *q = qdisc_priv(sch); | |
f38c39d6 PM |
62 | struct Qdisc *child = q->qdisc; |
63 | int ret; | |
1da177e4 | 64 | |
eeca6688 ED |
65 | q->vars.qavg = red_calc_qavg(&q->parms, |
66 | &q->vars, | |
67 | child->qstats.backlog); | |
1da177e4 | 68 | |
eeca6688 ED |
69 | if (red_is_idling(&q->vars)) |
70 | red_end_of_idle_period(&q->vars); | |
1da177e4 | 71 | |
eeca6688 | 72 | switch (red_action(&q->parms, &q->vars, q->vars.qavg)) { |
cc7ec456 ED |
73 | case RED_DONT_MARK: |
74 | break; | |
75 | ||
76 | case RED_PROB_MARK: | |
25331d6c | 77 | qdisc_qstats_overlimit(sch); |
cc7ec456 ED |
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: | |
25331d6c | 87 | qdisc_qstats_overlimit(sch); |
cc7ec456 ED |
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; | |
1da177e4 LT |
96 | } |
97 | ||
5f86173b | 98 | ret = qdisc_enqueue(skb, child); |
f38c39d6 | 99 | if (likely(ret == NET_XMIT_SUCCESS)) { |
f38c39d6 | 100 | sch->q.qlen++; |
378a2f09 | 101 | } else if (net_xmit_drop_count(ret)) { |
f38c39d6 | 102 | q->stats.pdrop++; |
25331d6c | 103 | qdisc_qstats_drop(sch); |
f38c39d6 PM |
104 | } |
105 | return ret; | |
6b31b28a TG |
106 | |
107 | congestion_drop: | |
9e178ff2 | 108 | qdisc_drop(skb, sch); |
1da177e4 LT |
109 | return NET_XMIT_CN; |
110 | } | |
111 | ||
cc7ec456 | 112 | static struct sk_buff *red_dequeue(struct Qdisc *sch) |
1da177e4 LT |
113 | { |
114 | struct sk_buff *skb; | |
115 | struct red_sched_data *q = qdisc_priv(sch); | |
f38c39d6 | 116 | struct Qdisc *child = q->qdisc; |
1da177e4 | 117 | |
f38c39d6 | 118 | skb = child->dequeue(child); |
9190b3b3 ED |
119 | if (skb) { |
120 | qdisc_bstats_update(sch, skb); | |
f38c39d6 | 121 | sch->q.qlen--; |
9190b3b3 | 122 | } else { |
eeca6688 ED |
123 | if (!red_is_idling(&q->vars)) |
124 | red_start_of_idle_period(&q->vars); | |
9190b3b3 | 125 | } |
9e178ff2 | 126 | return skb; |
1da177e4 LT |
127 | } |
128 | ||
cc7ec456 | 129 | static struct sk_buff *red_peek(struct Qdisc *sch) |
8e3af978 JP |
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 | ||
cc7ec456 | 137 | static unsigned int red_drop(struct Qdisc *sch) |
1da177e4 | 138 | { |
1da177e4 | 139 | struct red_sched_data *q = qdisc_priv(sch); |
f38c39d6 PM |
140 | struct Qdisc *child = q->qdisc; |
141 | unsigned int len; | |
1da177e4 | 142 | |
f38c39d6 | 143 | if (child->ops->drop && (len = child->ops->drop(child)) > 0) { |
6b31b28a | 144 | q->stats.other++; |
25331d6c | 145 | qdisc_qstats_drop(sch); |
f38c39d6 | 146 | sch->q.qlen--; |
1da177e4 LT |
147 | return len; |
148 | } | |
6b31b28a | 149 | |
eeca6688 ED |
150 | if (!red_is_idling(&q->vars)) |
151 | red_start_of_idle_period(&q->vars); | |
6a1b63d4 | 152 | |
1da177e4 LT |
153 | return 0; |
154 | } | |
155 | ||
cc7ec456 | 156 | static void red_reset(struct Qdisc *sch) |
1da177e4 LT |
157 | { |
158 | struct red_sched_data *q = qdisc_priv(sch); | |
159 | ||
f38c39d6 PM |
160 | qdisc_reset(q->qdisc); |
161 | sch->q.qlen = 0; | |
eeca6688 | 162 | red_restart(&q->vars); |
1da177e4 LT |
163 | } |
164 | ||
f38c39d6 PM |
165 | static void red_destroy(struct Qdisc *sch) |
166 | { | |
167 | struct red_sched_data *q = qdisc_priv(sch); | |
8af2a218 ED |
168 | |
169 | del_timer_sync(&q->adapt_timer); | |
f38c39d6 PM |
170 | qdisc_destroy(q->qdisc); |
171 | } | |
172 | ||
27a3421e PM |
173 | static 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 }, | |
a73ed26b | 176 | [TCA_RED_MAX_P] = { .type = NLA_U32 }, |
27a3421e PM |
177 | }; |
178 | ||
1e90474c | 179 | static int red_change(struct Qdisc *sch, struct nlattr *opt) |
1da177e4 LT |
180 | { |
181 | struct red_sched_data *q = qdisc_priv(sch); | |
1e90474c | 182 | struct nlattr *tb[TCA_RED_MAX + 1]; |
1da177e4 | 183 | struct tc_red_qopt *ctl; |
f38c39d6 | 184 | struct Qdisc *child = NULL; |
cee63723 | 185 | int err; |
a73ed26b | 186 | u32 max_P; |
1da177e4 | 187 | |
cee63723 | 188 | if (opt == NULL) |
dba051f3 TG |
189 | return -EINVAL; |
190 | ||
27a3421e | 191 | err = nla_parse_nested(tb, TCA_RED_MAX, opt, red_policy); |
cee63723 PM |
192 | if (err < 0) |
193 | return err; | |
194 | ||
1e90474c | 195 | if (tb[TCA_RED_PARMS] == NULL || |
27a3421e | 196 | tb[TCA_RED_STAB] == NULL) |
1da177e4 LT |
197 | return -EINVAL; |
198 | ||
a73ed26b ED |
199 | max_P = tb[TCA_RED_MAX_P] ? nla_get_u32(tb[TCA_RED_MAX_P]) : 0; |
200 | ||
1e90474c | 201 | ctl = nla_data(tb[TCA_RED_PARMS]); |
1da177e4 | 202 | |
f38c39d6 | 203 | if (ctl->limit > 0) { |
fb0305ce PM |
204 | child = fifo_create_dflt(sch, &bfifo_qdisc_ops, ctl->limit); |
205 | if (IS_ERR(child)) | |
206 | return PTR_ERR(child); | |
f38c39d6 PM |
207 | } |
208 | ||
1da177e4 LT |
209 | sch_tree_lock(sch); |
210 | q->flags = ctl->flags; | |
1da177e4 | 211 | q->limit = ctl->limit; |
5e50da01 | 212 | if (child) { |
2ccccf5f WC |
213 | qdisc_tree_reduce_backlog(q->qdisc, q->qdisc->q.qlen, |
214 | q->qdisc->qstats.backlog); | |
b94c8afc PM |
215 | qdisc_destroy(q->qdisc); |
216 | q->qdisc = child; | |
5e50da01 | 217 | } |
1da177e4 | 218 | |
eeca6688 ED |
219 | red_set_parms(&q->parms, |
220 | ctl->qth_min, ctl->qth_max, ctl->Wlog, | |
a73ed26b ED |
221 | ctl->Plog, ctl->Scell_log, |
222 | nla_data(tb[TCA_RED_STAB]), | |
223 | max_P); | |
eeca6688 | 224 | red_set_vars(&q->vars); |
6b31b28a | 225 | |
8af2a218 ED |
226 | del_timer(&q->adapt_timer); |
227 | if (ctl->flags & TC_RED_ADAPTATIVE) | |
228 | mod_timer(&q->adapt_timer, jiffies + HZ/2); | |
229 | ||
1ee5fa1e | 230 | if (!q->qdisc->q.qlen) |
eeca6688 | 231 | red_start_of_idle_period(&q->vars); |
dba051f3 | 232 | |
1da177e4 LT |
233 | sch_tree_unlock(sch); |
234 | return 0; | |
235 | } | |
236 | ||
8af2a218 ED |
237 | static inline void red_adaptative_timer(unsigned long arg) |
238 | { | |
239 | struct Qdisc *sch = (struct Qdisc *)arg; | |
240 | struct red_sched_data *q = qdisc_priv(sch); | |
241 | spinlock_t *root_lock = qdisc_lock(qdisc_root_sleeping(sch)); | |
242 | ||
243 | spin_lock(root_lock); | |
eeca6688 | 244 | red_adaptative_algo(&q->parms, &q->vars); |
8af2a218 ED |
245 | mod_timer(&q->adapt_timer, jiffies + HZ/2); |
246 | spin_unlock(root_lock); | |
247 | } | |
248 | ||
cc7ec456 | 249 | static int red_init(struct Qdisc *sch, struct nlattr *opt) |
1da177e4 | 250 | { |
f38c39d6 PM |
251 | struct red_sched_data *q = qdisc_priv(sch); |
252 | ||
253 | q->qdisc = &noop_qdisc; | |
8af2a218 | 254 | setup_timer(&q->adapt_timer, red_adaptative_timer, (unsigned long)sch); |
1da177e4 LT |
255 | return red_change(sch, opt); |
256 | } | |
257 | ||
258 | static int red_dump(struct Qdisc *sch, struct sk_buff *skb) | |
259 | { | |
260 | struct red_sched_data *q = qdisc_priv(sch); | |
1e90474c | 261 | struct nlattr *opts = NULL; |
6b31b28a TG |
262 | struct tc_red_qopt opt = { |
263 | .limit = q->limit, | |
264 | .flags = q->flags, | |
265 | .qth_min = q->parms.qth_min >> q->parms.Wlog, | |
266 | .qth_max = q->parms.qth_max >> q->parms.Wlog, | |
267 | .Wlog = q->parms.Wlog, | |
268 | .Plog = q->parms.Plog, | |
269 | .Scell_log = q->parms.Scell_log, | |
270 | }; | |
1da177e4 | 271 | |
0dfb33a0 | 272 | sch->qstats.backlog = q->qdisc->qstats.backlog; |
1e90474c PM |
273 | opts = nla_nest_start(skb, TCA_OPTIONS); |
274 | if (opts == NULL) | |
275 | goto nla_put_failure; | |
1b34ec43 DM |
276 | if (nla_put(skb, TCA_RED_PARMS, sizeof(opt), &opt) || |
277 | nla_put_u32(skb, TCA_RED_MAX_P, q->parms.max_P)) | |
278 | goto nla_put_failure; | |
1e90474c | 279 | return nla_nest_end(skb, opts); |
1da177e4 | 280 | |
1e90474c | 281 | nla_put_failure: |
bc3ed28c TG |
282 | nla_nest_cancel(skb, opts); |
283 | return -EMSGSIZE; | |
1da177e4 LT |
284 | } |
285 | ||
286 | static int red_dump_stats(struct Qdisc *sch, struct gnet_dump *d) | |
287 | { | |
288 | struct red_sched_data *q = qdisc_priv(sch); | |
6b31b28a TG |
289 | struct tc_red_xstats st = { |
290 | .early = q->stats.prob_drop + q->stats.forced_drop, | |
291 | .pdrop = q->stats.pdrop, | |
292 | .other = q->stats.other, | |
293 | .marked = q->stats.prob_mark + q->stats.forced_mark, | |
294 | }; | |
295 | ||
296 | return gnet_stats_copy_app(d, &st, sizeof(st)); | |
1da177e4 LT |
297 | } |
298 | ||
f38c39d6 PM |
299 | static int red_dump_class(struct Qdisc *sch, unsigned long cl, |
300 | struct sk_buff *skb, struct tcmsg *tcm) | |
301 | { | |
302 | struct red_sched_data *q = qdisc_priv(sch); | |
303 | ||
f38c39d6 PM |
304 | tcm->tcm_handle |= TC_H_MIN(1); |
305 | tcm->tcm_info = q->qdisc->handle; | |
306 | return 0; | |
307 | } | |
308 | ||
309 | static int red_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, | |
310 | struct Qdisc **old) | |
311 | { | |
312 | struct red_sched_data *q = qdisc_priv(sch); | |
313 | ||
314 | if (new == NULL) | |
315 | new = &noop_qdisc; | |
316 | ||
86a7996c | 317 | *old = qdisc_replace(sch, new, &q->qdisc); |
f38c39d6 PM |
318 | return 0; |
319 | } | |
320 | ||
321 | static struct Qdisc *red_leaf(struct Qdisc *sch, unsigned long arg) | |
322 | { | |
323 | struct red_sched_data *q = qdisc_priv(sch); | |
324 | return q->qdisc; | |
325 | } | |
326 | ||
327 | static unsigned long red_get(struct Qdisc *sch, u32 classid) | |
328 | { | |
329 | return 1; | |
330 | } | |
331 | ||
332 | static void red_put(struct Qdisc *sch, unsigned long arg) | |
333 | { | |
f38c39d6 PM |
334 | } |
335 | ||
f38c39d6 PM |
336 | static void red_walk(struct Qdisc *sch, struct qdisc_walker *walker) |
337 | { | |
338 | if (!walker->stop) { | |
339 | if (walker->count >= walker->skip) | |
340 | if (walker->fn(sch, 1, walker) < 0) { | |
341 | walker->stop = 1; | |
342 | return; | |
343 | } | |
344 | walker->count++; | |
345 | } | |
346 | } | |
347 | ||
20fea08b | 348 | static const struct Qdisc_class_ops red_class_ops = { |
f38c39d6 PM |
349 | .graft = red_graft, |
350 | .leaf = red_leaf, | |
351 | .get = red_get, | |
352 | .put = red_put, | |
f38c39d6 | 353 | .walk = red_walk, |
f38c39d6 PM |
354 | .dump = red_dump_class, |
355 | }; | |
356 | ||
20fea08b | 357 | static struct Qdisc_ops red_qdisc_ops __read_mostly = { |
1da177e4 LT |
358 | .id = "red", |
359 | .priv_size = sizeof(struct red_sched_data), | |
f38c39d6 | 360 | .cl_ops = &red_class_ops, |
1da177e4 LT |
361 | .enqueue = red_enqueue, |
362 | .dequeue = red_dequeue, | |
8e3af978 | 363 | .peek = red_peek, |
1da177e4 LT |
364 | .drop = red_drop, |
365 | .init = red_init, | |
366 | .reset = red_reset, | |
f38c39d6 | 367 | .destroy = red_destroy, |
1da177e4 LT |
368 | .change = red_change, |
369 | .dump = red_dump, | |
370 | .dump_stats = red_dump_stats, | |
371 | .owner = THIS_MODULE, | |
372 | }; | |
373 | ||
374 | static int __init red_module_init(void) | |
375 | { | |
376 | return register_qdisc(&red_qdisc_ops); | |
377 | } | |
dba051f3 TG |
378 | |
379 | static void __exit red_module_exit(void) | |
1da177e4 LT |
380 | { |
381 | unregister_qdisc(&red_qdisc_ops); | |
382 | } | |
dba051f3 | 383 | |
1da177e4 LT |
384 | module_init(red_module_init) |
385 | module_exit(red_module_exit) | |
dba051f3 | 386 | |
1da177e4 | 387 | MODULE_LICENSE("GPL"); |