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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 | ||
39 | struct red_sched_data | |
40 | { | |
6b31b28a TG |
41 | u32 limit; /* HARD maximal queue length */ |
42 | unsigned char flags; | |
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 | ||
dba051f3 | 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 TG |
69 | switch (red_action(&q->parms, q->parms.qavg)) { |
70 | case RED_DONT_MARK: | |
71 | break; | |
1da177e4 | 72 | |
6b31b28a TG |
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 | } | |
1da177e4 | 79 | |
6b31b28a TG |
80 | q->stats.prob_mark++; |
81 | break; | |
82 | ||
83 | case RED_HARD_MARK: | |
84 | sch->qstats.overlimits++; | |
bdc450a0 TG |
85 | if (red_use_harddrop(q) || !red_use_ecn(q) || |
86 | !INET_ECN_set_ce(skb)) { | |
6b31b28a TG |
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)) { |
0abf77e5 | 97 | sch->bstats.bytes += qdisc_pkt_len(skb); |
f38c39d6 PM |
98 | sch->bstats.packets++; |
99 | sch->q.qlen++; | |
378a2f09 | 100 | } else if (net_xmit_drop_count(ret)) { |
f38c39d6 PM |
101 | q->stats.pdrop++; |
102 | sch->qstats.drops++; | |
103 | } | |
104 | return ret; | |
6b31b28a TG |
105 | |
106 | congestion_drop: | |
9e178ff2 | 107 | qdisc_drop(skb, sch); |
1da177e4 LT |
108 | return NET_XMIT_CN; |
109 | } | |
110 | ||
dba051f3 | 111 | static struct sk_buff * red_dequeue(struct Qdisc* sch) |
1da177e4 LT |
112 | { |
113 | struct sk_buff *skb; | |
114 | struct red_sched_data *q = qdisc_priv(sch); | |
f38c39d6 | 115 | struct Qdisc *child = q->qdisc; |
1da177e4 | 116 | |
f38c39d6 PM |
117 | skb = child->dequeue(child); |
118 | if (skb) | |
119 | sch->q.qlen--; | |
120 | else if (!red_is_idling(&q->parms)) | |
9e178ff2 TG |
121 | red_start_of_idle_period(&q->parms); |
122 | ||
123 | return skb; | |
1da177e4 LT |
124 | } |
125 | ||
8e3af978 JP |
126 | static struct sk_buff * red_peek(struct Qdisc* sch) |
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 | ||
1da177e4 LT |
134 | static unsigned int red_drop(struct Qdisc* sch) |
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 | ||
153 | static void red_reset(struct Qdisc* sch) | |
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); | |
165 | qdisc_destroy(q->qdisc); | |
166 | } | |
167 | ||
27a3421e PM |
168 | static const struct nla_policy red_policy[TCA_RED_MAX + 1] = { |
169 | [TCA_RED_PARMS] = { .len = sizeof(struct tc_red_qopt) }, | |
170 | [TCA_RED_STAB] = { .len = RED_STAB_SIZE }, | |
171 | }; | |
172 | ||
1e90474c | 173 | static int red_change(struct Qdisc *sch, struct nlattr *opt) |
1da177e4 LT |
174 | { |
175 | struct red_sched_data *q = qdisc_priv(sch); | |
1e90474c | 176 | struct nlattr *tb[TCA_RED_MAX + 1]; |
1da177e4 | 177 | struct tc_red_qopt *ctl; |
f38c39d6 | 178 | struct Qdisc *child = NULL; |
cee63723 | 179 | int err; |
1da177e4 | 180 | |
cee63723 | 181 | if (opt == NULL) |
dba051f3 TG |
182 | return -EINVAL; |
183 | ||
27a3421e | 184 | err = nla_parse_nested(tb, TCA_RED_MAX, opt, red_policy); |
cee63723 PM |
185 | if (err < 0) |
186 | return err; | |
187 | ||
1e90474c | 188 | if (tb[TCA_RED_PARMS] == NULL || |
27a3421e | 189 | tb[TCA_RED_STAB] == NULL) |
1da177e4 LT |
190 | return -EINVAL; |
191 | ||
1e90474c | 192 | ctl = nla_data(tb[TCA_RED_PARMS]); |
1da177e4 | 193 | |
f38c39d6 | 194 | if (ctl->limit > 0) { |
fb0305ce PM |
195 | child = fifo_create_dflt(sch, &bfifo_qdisc_ops, ctl->limit); |
196 | if (IS_ERR(child)) | |
197 | return PTR_ERR(child); | |
f38c39d6 PM |
198 | } |
199 | ||
1da177e4 LT |
200 | sch_tree_lock(sch); |
201 | q->flags = ctl->flags; | |
1da177e4 | 202 | q->limit = ctl->limit; |
5e50da01 PM |
203 | if (child) { |
204 | qdisc_tree_decrease_qlen(q->qdisc, q->qdisc->q.qlen); | |
b94c8afc PM |
205 | qdisc_destroy(q->qdisc); |
206 | q->qdisc = child; | |
5e50da01 | 207 | } |
1da177e4 | 208 | |
6b31b28a TG |
209 | red_set_parms(&q->parms, ctl->qth_min, ctl->qth_max, ctl->Wlog, |
210 | ctl->Plog, ctl->Scell_log, | |
1e90474c | 211 | nla_data(tb[TCA_RED_STAB])); |
6b31b28a | 212 | |
b03efcfb | 213 | if (skb_queue_empty(&sch->q)) |
6b31b28a | 214 | red_end_of_idle_period(&q->parms); |
dba051f3 | 215 | |
1da177e4 LT |
216 | sch_tree_unlock(sch); |
217 | return 0; | |
218 | } | |
219 | ||
1e90474c | 220 | static int red_init(struct Qdisc* sch, struct nlattr *opt) |
1da177e4 | 221 | { |
f38c39d6 PM |
222 | struct red_sched_data *q = qdisc_priv(sch); |
223 | ||
224 | q->qdisc = &noop_qdisc; | |
1da177e4 LT |
225 | return red_change(sch, opt); |
226 | } | |
227 | ||
228 | static int red_dump(struct Qdisc *sch, struct sk_buff *skb) | |
229 | { | |
230 | struct red_sched_data *q = qdisc_priv(sch); | |
1e90474c | 231 | struct nlattr *opts = NULL; |
6b31b28a TG |
232 | struct tc_red_qopt opt = { |
233 | .limit = q->limit, | |
234 | .flags = q->flags, | |
235 | .qth_min = q->parms.qth_min >> q->parms.Wlog, | |
236 | .qth_max = q->parms.qth_max >> q->parms.Wlog, | |
237 | .Wlog = q->parms.Wlog, | |
238 | .Plog = q->parms.Plog, | |
239 | .Scell_log = q->parms.Scell_log, | |
240 | }; | |
1da177e4 | 241 | |
1e90474c PM |
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); | |
1da177e4 | 247 | |
1e90474c | 248 | nla_put_failure: |
bc3ed28c TG |
249 | nla_nest_cancel(skb, opts); |
250 | return -EMSGSIZE; | |
1da177e4 LT |
251 | } |
252 | ||
253 | static int red_dump_stats(struct Qdisc *sch, struct gnet_dump *d) | |
254 | { | |
255 | struct red_sched_data *q = qdisc_priv(sch); | |
6b31b28a TG |
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)); | |
1da177e4 LT |
264 | } |
265 | ||
f38c39d6 PM |
266 | static 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 | ||
f38c39d6 PM |
271 | tcm->tcm_handle |= TC_H_MIN(1); |
272 | tcm->tcm_info = q->qdisc->handle; | |
273 | return 0; | |
274 | } | |
275 | ||
276 | static 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); | |
b94c8afc PM |
285 | *old = q->qdisc; |
286 | q->qdisc = new; | |
5e50da01 | 287 | qdisc_tree_decrease_qlen(*old, (*old)->q.qlen); |
f38c39d6 | 288 | qdisc_reset(*old); |
f38c39d6 PM |
289 | sch_tree_unlock(sch); |
290 | return 0; | |
291 | } | |
292 | ||
293 | static 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 | ||
299 | static unsigned long red_get(struct Qdisc *sch, u32 classid) | |
300 | { | |
301 | return 1; | |
302 | } | |
303 | ||
304 | static void red_put(struct Qdisc *sch, unsigned long arg) | |
305 | { | |
306 | return; | |
307 | } | |
308 | ||
f38c39d6 PM |
309 | static void red_walk(struct Qdisc *sch, struct qdisc_walker *walker) |
310 | { | |
311 | if (!walker->stop) { | |
312 | if (walker->count >= walker->skip) | |
313 | if (walker->fn(sch, 1, walker) < 0) { | |
314 | walker->stop = 1; | |
315 | return; | |
316 | } | |
317 | walker->count++; | |
318 | } | |
319 | } | |
320 | ||
20fea08b | 321 | static const struct Qdisc_class_ops red_class_ops = { |
f38c39d6 PM |
322 | .graft = red_graft, |
323 | .leaf = red_leaf, | |
324 | .get = red_get, | |
325 | .put = red_put, | |
f38c39d6 | 326 | .walk = red_walk, |
f38c39d6 PM |
327 | .dump = red_dump_class, |
328 | }; | |
329 | ||
20fea08b | 330 | static struct Qdisc_ops red_qdisc_ops __read_mostly = { |
1da177e4 LT |
331 | .id = "red", |
332 | .priv_size = sizeof(struct red_sched_data), | |
f38c39d6 | 333 | .cl_ops = &red_class_ops, |
1da177e4 LT |
334 | .enqueue = red_enqueue, |
335 | .dequeue = red_dequeue, | |
8e3af978 | 336 | .peek = red_peek, |
1da177e4 LT |
337 | .drop = red_drop, |
338 | .init = red_init, | |
339 | .reset = red_reset, | |
f38c39d6 | 340 | .destroy = red_destroy, |
1da177e4 LT |
341 | .change = red_change, |
342 | .dump = red_dump, | |
343 | .dump_stats = red_dump_stats, | |
344 | .owner = THIS_MODULE, | |
345 | }; | |
346 | ||
347 | static int __init red_module_init(void) | |
348 | { | |
349 | return register_qdisc(&red_qdisc_ops); | |
350 | } | |
dba051f3 TG |
351 | |
352 | static void __exit red_module_exit(void) | |
1da177e4 LT |
353 | { |
354 | unregister_qdisc(&red_qdisc_ops); | |
355 | } | |
dba051f3 | 356 | |
1da177e4 LT |
357 | module_init(red_module_init) |
358 | module_exit(red_module_exit) | |
dba051f3 | 359 | |
1da177e4 | 360 | MODULE_LICENSE("GPL"); |