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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 TG |
43 | struct red_parms parms; |
44 | struct red_stats stats; | |
f38c39d6 | 45 | struct Qdisc *qdisc; |
1da177e4 LT |
46 | }; |
47 | ||
6b31b28a | 48 | static inline int red_use_ecn(struct red_sched_data *q) |
1da177e4 | 49 | { |
6b31b28a | 50 | return q->flags & TC_RED_ECN; |
1da177e4 LT |
51 | } |
52 | ||
bdc450a0 TG |
53 | static inline int red_use_harddrop(struct red_sched_data *q) |
54 | { | |
55 | return q->flags & TC_RED_HARDDROP; | |
56 | } | |
57 | ||
cc7ec456 | 58 | static int red_enqueue(struct sk_buff *skb, struct Qdisc *sch) |
1da177e4 LT |
59 | { |
60 | struct red_sched_data *q = qdisc_priv(sch); | |
f38c39d6 PM |
61 | struct Qdisc *child = q->qdisc; |
62 | int ret; | |
1da177e4 | 63 | |
f38c39d6 | 64 | q->parms.qavg = red_calc_qavg(&q->parms, child->qstats.backlog); |
1da177e4 | 65 | |
6b31b28a TG |
66 | if (red_is_idling(&q->parms)) |
67 | red_end_of_idle_period(&q->parms); | |
1da177e4 | 68 | |
6b31b28a | 69 | switch (red_action(&q->parms, q->parms.qavg)) { |
cc7ec456 ED |
70 | case RED_DONT_MARK: |
71 | break; | |
72 | ||
73 | case RED_PROB_MARK: | |
74 | sch->qstats.overlimits++; | |
75 | if (!red_use_ecn(q) || !INET_ECN_set_ce(skb)) { | |
76 | q->stats.prob_drop++; | |
77 | goto congestion_drop; | |
78 | } | |
79 | ||
80 | q->stats.prob_mark++; | |
81 | break; | |
82 | ||
83 | case RED_HARD_MARK: | |
84 | sch->qstats.overlimits++; | |
85 | if (red_use_harddrop(q) || !red_use_ecn(q) || | |
86 | !INET_ECN_set_ce(skb)) { | |
87 | q->stats.forced_drop++; | |
88 | goto congestion_drop; | |
89 | } | |
90 | ||
91 | q->stats.forced_mark++; | |
92 | break; | |
1da177e4 LT |
93 | } |
94 | ||
5f86173b | 95 | ret = qdisc_enqueue(skb, child); |
f38c39d6 | 96 | if (likely(ret == NET_XMIT_SUCCESS)) { |
f38c39d6 | 97 | sch->q.qlen++; |
378a2f09 | 98 | } else if (net_xmit_drop_count(ret)) { |
f38c39d6 PM |
99 | q->stats.pdrop++; |
100 | sch->qstats.drops++; | |
101 | } | |
102 | return ret; | |
6b31b28a TG |
103 | |
104 | congestion_drop: | |
9e178ff2 | 105 | qdisc_drop(skb, sch); |
1da177e4 LT |
106 | return NET_XMIT_CN; |
107 | } | |
108 | ||
cc7ec456 | 109 | static struct sk_buff *red_dequeue(struct Qdisc *sch) |
1da177e4 LT |
110 | { |
111 | struct sk_buff *skb; | |
112 | struct red_sched_data *q = qdisc_priv(sch); | |
f38c39d6 | 113 | struct Qdisc *child = q->qdisc; |
1da177e4 | 114 | |
f38c39d6 | 115 | skb = child->dequeue(child); |
9190b3b3 ED |
116 | if (skb) { |
117 | qdisc_bstats_update(sch, skb); | |
f38c39d6 | 118 | sch->q.qlen--; |
9190b3b3 ED |
119 | } else { |
120 | if (!red_is_idling(&q->parms)) | |
121 | red_start_of_idle_period(&q->parms); | |
122 | } | |
9e178ff2 | 123 | return skb; |
1da177e4 LT |
124 | } |
125 | ||
cc7ec456 | 126 | static struct sk_buff *red_peek(struct Qdisc *sch) |
8e3af978 JP |
127 | { |
128 | struct red_sched_data *q = qdisc_priv(sch); | |
129 | struct Qdisc *child = q->qdisc; | |
130 | ||
131 | return child->ops->peek(child); | |
132 | } | |
133 | ||
cc7ec456 | 134 | static unsigned int red_drop(struct Qdisc *sch) |
1da177e4 | 135 | { |
1da177e4 | 136 | struct red_sched_data *q = qdisc_priv(sch); |
f38c39d6 PM |
137 | struct Qdisc *child = q->qdisc; |
138 | unsigned int len; | |
1da177e4 | 139 | |
f38c39d6 | 140 | if (child->ops->drop && (len = child->ops->drop(child)) > 0) { |
6b31b28a | 141 | q->stats.other++; |
f38c39d6 PM |
142 | sch->qstats.drops++; |
143 | sch->q.qlen--; | |
1da177e4 LT |
144 | return len; |
145 | } | |
6b31b28a | 146 | |
6a1b63d4 TG |
147 | if (!red_is_idling(&q->parms)) |
148 | red_start_of_idle_period(&q->parms); | |
149 | ||
1da177e4 LT |
150 | return 0; |
151 | } | |
152 | ||
cc7ec456 | 153 | static void red_reset(struct Qdisc *sch) |
1da177e4 LT |
154 | { |
155 | struct red_sched_data *q = qdisc_priv(sch); | |
156 | ||
f38c39d6 PM |
157 | qdisc_reset(q->qdisc); |
158 | sch->q.qlen = 0; | |
6b31b28a | 159 | red_restart(&q->parms); |
1da177e4 LT |
160 | } |
161 | ||
f38c39d6 PM |
162 | static void red_destroy(struct Qdisc *sch) |
163 | { | |
164 | struct red_sched_data *q = qdisc_priv(sch); | |
8af2a218 ED |
165 | |
166 | del_timer_sync(&q->adapt_timer); | |
f38c39d6 PM |
167 | qdisc_destroy(q->qdisc); |
168 | } | |
169 | ||
27a3421e PM |
170 | static const struct nla_policy red_policy[TCA_RED_MAX + 1] = { |
171 | [TCA_RED_PARMS] = { .len = sizeof(struct tc_red_qopt) }, | |
172 | [TCA_RED_STAB] = { .len = RED_STAB_SIZE }, | |
173 | }; | |
174 | ||
1e90474c | 175 | static int red_change(struct Qdisc *sch, struct nlattr *opt) |
1da177e4 LT |
176 | { |
177 | struct red_sched_data *q = qdisc_priv(sch); | |
1e90474c | 178 | struct nlattr *tb[TCA_RED_MAX + 1]; |
1da177e4 | 179 | struct tc_red_qopt *ctl; |
f38c39d6 | 180 | struct Qdisc *child = NULL; |
cee63723 | 181 | int err; |
1da177e4 | 182 | |
cee63723 | 183 | if (opt == NULL) |
dba051f3 TG |
184 | return -EINVAL; |
185 | ||
27a3421e | 186 | err = nla_parse_nested(tb, TCA_RED_MAX, opt, red_policy); |
cee63723 PM |
187 | if (err < 0) |
188 | return err; | |
189 | ||
1e90474c | 190 | if (tb[TCA_RED_PARMS] == NULL || |
27a3421e | 191 | tb[TCA_RED_STAB] == NULL) |
1da177e4 LT |
192 | return -EINVAL; |
193 | ||
1e90474c | 194 | ctl = nla_data(tb[TCA_RED_PARMS]); |
1da177e4 | 195 | |
f38c39d6 | 196 | if (ctl->limit > 0) { |
fb0305ce PM |
197 | child = fifo_create_dflt(sch, &bfifo_qdisc_ops, ctl->limit); |
198 | if (IS_ERR(child)) | |
199 | return PTR_ERR(child); | |
f38c39d6 PM |
200 | } |
201 | ||
1da177e4 LT |
202 | sch_tree_lock(sch); |
203 | q->flags = ctl->flags; | |
1da177e4 | 204 | q->limit = ctl->limit; |
5e50da01 PM |
205 | if (child) { |
206 | qdisc_tree_decrease_qlen(q->qdisc, q->qdisc->q.qlen); | |
b94c8afc PM |
207 | qdisc_destroy(q->qdisc); |
208 | q->qdisc = child; | |
5e50da01 | 209 | } |
1da177e4 | 210 | |
6b31b28a TG |
211 | red_set_parms(&q->parms, ctl->qth_min, ctl->qth_max, ctl->Wlog, |
212 | ctl->Plog, ctl->Scell_log, | |
1e90474c | 213 | nla_data(tb[TCA_RED_STAB])); |
6b31b28a | 214 | |
8af2a218 ED |
215 | del_timer(&q->adapt_timer); |
216 | if (ctl->flags & TC_RED_ADAPTATIVE) | |
217 | mod_timer(&q->adapt_timer, jiffies + HZ/2); | |
218 | ||
1ee5fa1e ED |
219 | if (!q->qdisc->q.qlen) |
220 | red_start_of_idle_period(&q->parms); | |
dba051f3 | 221 | |
1da177e4 LT |
222 | sch_tree_unlock(sch); |
223 | return 0; | |
224 | } | |
225 | ||
8af2a218 ED |
226 | static inline void red_adaptative_timer(unsigned long arg) |
227 | { | |
228 | struct Qdisc *sch = (struct Qdisc *)arg; | |
229 | struct red_sched_data *q = qdisc_priv(sch); | |
230 | spinlock_t *root_lock = qdisc_lock(qdisc_root_sleeping(sch)); | |
231 | ||
232 | spin_lock(root_lock); | |
233 | red_adaptative_algo(&q->parms); | |
234 | mod_timer(&q->adapt_timer, jiffies + HZ/2); | |
235 | spin_unlock(root_lock); | |
236 | } | |
237 | ||
cc7ec456 | 238 | static int red_init(struct Qdisc *sch, struct nlattr *opt) |
1da177e4 | 239 | { |
f38c39d6 PM |
240 | struct red_sched_data *q = qdisc_priv(sch); |
241 | ||
242 | q->qdisc = &noop_qdisc; | |
8af2a218 | 243 | setup_timer(&q->adapt_timer, red_adaptative_timer, (unsigned long)sch); |
1da177e4 LT |
244 | return red_change(sch, opt); |
245 | } | |
246 | ||
247 | static int red_dump(struct Qdisc *sch, struct sk_buff *skb) | |
248 | { | |
249 | struct red_sched_data *q = qdisc_priv(sch); | |
1e90474c | 250 | struct nlattr *opts = NULL; |
6b31b28a TG |
251 | struct tc_red_qopt opt = { |
252 | .limit = q->limit, | |
253 | .flags = q->flags, | |
254 | .qth_min = q->parms.qth_min >> q->parms.Wlog, | |
255 | .qth_max = q->parms.qth_max >> q->parms.Wlog, | |
256 | .Wlog = q->parms.Wlog, | |
257 | .Plog = q->parms.Plog, | |
258 | .Scell_log = q->parms.Scell_log, | |
259 | }; | |
1da177e4 | 260 | |
0dfb33a0 | 261 | sch->qstats.backlog = q->qdisc->qstats.backlog; |
1e90474c PM |
262 | opts = nla_nest_start(skb, TCA_OPTIONS); |
263 | if (opts == NULL) | |
264 | goto nla_put_failure; | |
265 | NLA_PUT(skb, TCA_RED_PARMS, sizeof(opt), &opt); | |
8af2a218 | 266 | NLA_PUT_U32(skb, TCA_RED_MAX_P, q->parms.max_P); |
1e90474c | 267 | return nla_nest_end(skb, opts); |
1da177e4 | 268 | |
1e90474c | 269 | nla_put_failure: |
bc3ed28c TG |
270 | nla_nest_cancel(skb, opts); |
271 | return -EMSGSIZE; | |
1da177e4 LT |
272 | } |
273 | ||
274 | static int red_dump_stats(struct Qdisc *sch, struct gnet_dump *d) | |
275 | { | |
276 | struct red_sched_data *q = qdisc_priv(sch); | |
6b31b28a TG |
277 | struct tc_red_xstats st = { |
278 | .early = q->stats.prob_drop + q->stats.forced_drop, | |
279 | .pdrop = q->stats.pdrop, | |
280 | .other = q->stats.other, | |
281 | .marked = q->stats.prob_mark + q->stats.forced_mark, | |
282 | }; | |
283 | ||
284 | return gnet_stats_copy_app(d, &st, sizeof(st)); | |
1da177e4 LT |
285 | } |
286 | ||
f38c39d6 PM |
287 | static int red_dump_class(struct Qdisc *sch, unsigned long cl, |
288 | struct sk_buff *skb, struct tcmsg *tcm) | |
289 | { | |
290 | struct red_sched_data *q = qdisc_priv(sch); | |
291 | ||
f38c39d6 PM |
292 | tcm->tcm_handle |= TC_H_MIN(1); |
293 | tcm->tcm_info = q->qdisc->handle; | |
294 | return 0; | |
295 | } | |
296 | ||
297 | static int red_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, | |
298 | struct Qdisc **old) | |
299 | { | |
300 | struct red_sched_data *q = qdisc_priv(sch); | |
301 | ||
302 | if (new == NULL) | |
303 | new = &noop_qdisc; | |
304 | ||
305 | sch_tree_lock(sch); | |
b94c8afc PM |
306 | *old = q->qdisc; |
307 | q->qdisc = new; | |
5e50da01 | 308 | qdisc_tree_decrease_qlen(*old, (*old)->q.qlen); |
f38c39d6 | 309 | qdisc_reset(*old); |
f38c39d6 PM |
310 | sch_tree_unlock(sch); |
311 | return 0; | |
312 | } | |
313 | ||
314 | static struct Qdisc *red_leaf(struct Qdisc *sch, unsigned long arg) | |
315 | { | |
316 | struct red_sched_data *q = qdisc_priv(sch); | |
317 | return q->qdisc; | |
318 | } | |
319 | ||
320 | static unsigned long red_get(struct Qdisc *sch, u32 classid) | |
321 | { | |
322 | return 1; | |
323 | } | |
324 | ||
325 | static void red_put(struct Qdisc *sch, unsigned long arg) | |
326 | { | |
f38c39d6 PM |
327 | } |
328 | ||
f38c39d6 PM |
329 | static void red_walk(struct Qdisc *sch, struct qdisc_walker *walker) |
330 | { | |
331 | if (!walker->stop) { | |
332 | if (walker->count >= walker->skip) | |
333 | if (walker->fn(sch, 1, walker) < 0) { | |
334 | walker->stop = 1; | |
335 | return; | |
336 | } | |
337 | walker->count++; | |
338 | } | |
339 | } | |
340 | ||
20fea08b | 341 | static const struct Qdisc_class_ops red_class_ops = { |
f38c39d6 PM |
342 | .graft = red_graft, |
343 | .leaf = red_leaf, | |
344 | .get = red_get, | |
345 | .put = red_put, | |
f38c39d6 | 346 | .walk = red_walk, |
f38c39d6 PM |
347 | .dump = red_dump_class, |
348 | }; | |
349 | ||
20fea08b | 350 | static struct Qdisc_ops red_qdisc_ops __read_mostly = { |
1da177e4 LT |
351 | .id = "red", |
352 | .priv_size = sizeof(struct red_sched_data), | |
f38c39d6 | 353 | .cl_ops = &red_class_ops, |
1da177e4 LT |
354 | .enqueue = red_enqueue, |
355 | .dequeue = red_dequeue, | |
8e3af978 | 356 | .peek = red_peek, |
1da177e4 LT |
357 | .drop = red_drop, |
358 | .init = red_init, | |
359 | .reset = red_reset, | |
f38c39d6 | 360 | .destroy = red_destroy, |
1da177e4 LT |
361 | .change = red_change, |
362 | .dump = red_dump, | |
363 | .dump_stats = red_dump_stats, | |
364 | .owner = THIS_MODULE, | |
365 | }; | |
366 | ||
367 | static int __init red_module_init(void) | |
368 | { | |
369 | return register_qdisc(&red_qdisc_ops); | |
370 | } | |
dba051f3 TG |
371 | |
372 | static void __exit red_module_exit(void) | |
1da177e4 LT |
373 | { |
374 | unregister_qdisc(&red_qdisc_ops); | |
375 | } | |
dba051f3 | 376 | |
1da177e4 LT |
377 | module_init(red_module_init) |
378 | module_exit(red_module_exit) | |
dba051f3 | 379 | |
1da177e4 | 380 | MODULE_LICENSE("GPL"); |