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/netdevice.h> |
1da177e4 | 21 | #include <linux/skbuff.h> |
1da177e4 LT |
22 | #include <net/pkt_sched.h> |
23 | #include <net/inet_ecn.h> | |
6b31b28a | 24 | #include <net/red.h> |
1da177e4 LT |
25 | |
26 | ||
6b31b28a | 27 | /* Parameters, settable by user: |
1da177e4 LT |
28 | ----------------------------- |
29 | ||
30 | limit - bytes (must be > qth_max + burst) | |
31 | ||
32 | Hard limit on queue length, should be chosen >qth_max | |
33 | to allow packet bursts. This parameter does not | |
34 | affect the algorithms behaviour and can be chosen | |
35 | arbitrarily high (well, less than ram size) | |
36 | Really, this limit will never be reached | |
37 | if RED works correctly. | |
1da177e4 LT |
38 | */ |
39 | ||
40 | struct red_sched_data | |
41 | { | |
6b31b28a TG |
42 | u32 limit; /* HARD maximal queue length */ |
43 | unsigned char flags; | |
44 | struct red_parms parms; | |
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 | ||
dba051f3 | 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 | |
f38c39d6 | 65 | q->parms.qavg = red_calc_qavg(&q->parms, child->qstats.backlog); |
1da177e4 | 66 | |
6b31b28a TG |
67 | if (red_is_idling(&q->parms)) |
68 | red_end_of_idle_period(&q->parms); | |
1da177e4 | 69 | |
6b31b28a TG |
70 | switch (red_action(&q->parms, q->parms.qavg)) { |
71 | case RED_DONT_MARK: | |
72 | break; | |
1da177e4 | 73 | |
6b31b28a TG |
74 | case RED_PROB_MARK: |
75 | sch->qstats.overlimits++; | |
76 | if (!red_use_ecn(q) || !INET_ECN_set_ce(skb)) { | |
77 | q->stats.prob_drop++; | |
78 | goto congestion_drop; | |
79 | } | |
1da177e4 | 80 | |
6b31b28a TG |
81 | q->stats.prob_mark++; |
82 | break; | |
83 | ||
84 | case RED_HARD_MARK: | |
85 | sch->qstats.overlimits++; | |
bdc450a0 TG |
86 | if (red_use_harddrop(q) || !red_use_ecn(q) || |
87 | !INET_ECN_set_ce(skb)) { | |
6b31b28a TG |
88 | q->stats.forced_drop++; |
89 | goto congestion_drop; | |
90 | } | |
91 | ||
92 | q->stats.forced_mark++; | |
93 | break; | |
1da177e4 LT |
94 | } |
95 | ||
f38c39d6 PM |
96 | ret = child->enqueue(skb, child); |
97 | if (likely(ret == NET_XMIT_SUCCESS)) { | |
98 | sch->bstats.bytes += skb->len; | |
99 | sch->bstats.packets++; | |
100 | sch->q.qlen++; | |
101 | } else { | |
102 | q->stats.pdrop++; | |
103 | sch->qstats.drops++; | |
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 | ||
dba051f3 | 112 | static int red_requeue(struct sk_buff *skb, struct Qdisc* sch) |
1da177e4 LT |
113 | { |
114 | struct red_sched_data *q = qdisc_priv(sch); | |
f38c39d6 PM |
115 | struct Qdisc *child = q->qdisc; |
116 | int ret; | |
1da177e4 | 117 | |
6b31b28a TG |
118 | if (red_is_idling(&q->parms)) |
119 | red_end_of_idle_period(&q->parms); | |
1da177e4 | 120 | |
f38c39d6 PM |
121 | ret = child->ops->requeue(skb, child); |
122 | if (likely(ret == NET_XMIT_SUCCESS)) { | |
123 | sch->qstats.requeues++; | |
124 | sch->q.qlen++; | |
125 | } | |
126 | return ret; | |
1da177e4 LT |
127 | } |
128 | ||
dba051f3 | 129 | static struct sk_buff * red_dequeue(struct Qdisc* sch) |
1da177e4 LT |
130 | { |
131 | struct sk_buff *skb; | |
132 | struct red_sched_data *q = qdisc_priv(sch); | |
f38c39d6 | 133 | struct Qdisc *child = q->qdisc; |
1da177e4 | 134 | |
f38c39d6 PM |
135 | skb = child->dequeue(child); |
136 | if (skb) | |
137 | sch->q.qlen--; | |
138 | else if (!red_is_idling(&q->parms)) | |
9e178ff2 TG |
139 | red_start_of_idle_period(&q->parms); |
140 | ||
141 | return skb; | |
1da177e4 LT |
142 | } |
143 | ||
144 | static unsigned int red_drop(struct Qdisc* sch) | |
145 | { | |
1da177e4 | 146 | struct red_sched_data *q = qdisc_priv(sch); |
f38c39d6 PM |
147 | struct Qdisc *child = q->qdisc; |
148 | unsigned int len; | |
1da177e4 | 149 | |
f38c39d6 | 150 | if (child->ops->drop && (len = child->ops->drop(child)) > 0) { |
6b31b28a | 151 | q->stats.other++; |
f38c39d6 PM |
152 | sch->qstats.drops++; |
153 | sch->q.qlen--; | |
1da177e4 LT |
154 | return len; |
155 | } | |
6b31b28a | 156 | |
6a1b63d4 TG |
157 | if (!red_is_idling(&q->parms)) |
158 | red_start_of_idle_period(&q->parms); | |
159 | ||
1da177e4 LT |
160 | return 0; |
161 | } | |
162 | ||
163 | static void red_reset(struct Qdisc* sch) | |
164 | { | |
165 | struct red_sched_data *q = qdisc_priv(sch); | |
166 | ||
f38c39d6 PM |
167 | qdisc_reset(q->qdisc); |
168 | sch->q.qlen = 0; | |
6b31b28a | 169 | red_restart(&q->parms); |
1da177e4 LT |
170 | } |
171 | ||
f38c39d6 PM |
172 | static void red_destroy(struct Qdisc *sch) |
173 | { | |
174 | struct red_sched_data *q = qdisc_priv(sch); | |
175 | qdisc_destroy(q->qdisc); | |
176 | } | |
177 | ||
178 | static struct Qdisc *red_create_dflt(struct net_device *dev, u32 limit) | |
179 | { | |
180 | struct Qdisc *q = qdisc_create_dflt(dev, &bfifo_qdisc_ops); | |
181 | struct rtattr *rta; | |
182 | int ret; | |
183 | ||
184 | if (q) { | |
185 | rta = kmalloc(RTA_LENGTH(sizeof(struct tc_fifo_qopt)), | |
186 | GFP_KERNEL); | |
187 | if (rta) { | |
188 | rta->rta_type = RTM_NEWQDISC; | |
189 | rta->rta_len = RTA_LENGTH(sizeof(struct tc_fifo_qopt)); | |
190 | ((struct tc_fifo_qopt *)RTA_DATA(rta))->limit = limit; | |
191 | ||
192 | ret = q->ops->change(q, rta); | |
193 | kfree(rta); | |
194 | ||
195 | if (ret == 0) | |
196 | return q; | |
197 | } | |
198 | qdisc_destroy(q); | |
199 | } | |
200 | return NULL; | |
201 | } | |
202 | ||
1da177e4 LT |
203 | static int red_change(struct Qdisc *sch, struct rtattr *opt) |
204 | { | |
205 | struct red_sched_data *q = qdisc_priv(sch); | |
dba051f3 | 206 | struct rtattr *tb[TCA_RED_MAX]; |
1da177e4 | 207 | struct tc_red_qopt *ctl; |
f38c39d6 | 208 | struct Qdisc *child = NULL; |
1da177e4 | 209 | |
dba051f3 TG |
210 | if (opt == NULL || rtattr_parse_nested(tb, TCA_RED_MAX, opt)) |
211 | return -EINVAL; | |
212 | ||
213 | if (tb[TCA_RED_PARMS-1] == NULL || | |
1da177e4 | 214 | RTA_PAYLOAD(tb[TCA_RED_PARMS-1]) < sizeof(*ctl) || |
dba051f3 TG |
215 | tb[TCA_RED_STAB-1] == NULL || |
216 | RTA_PAYLOAD(tb[TCA_RED_STAB-1]) < RED_STAB_SIZE) | |
1da177e4 LT |
217 | return -EINVAL; |
218 | ||
219 | ctl = RTA_DATA(tb[TCA_RED_PARMS-1]); | |
220 | ||
f38c39d6 PM |
221 | if (ctl->limit > 0) { |
222 | child = red_create_dflt(sch->dev, ctl->limit); | |
223 | if (child == NULL) | |
224 | return -ENOMEM; | |
225 | } | |
226 | ||
1da177e4 LT |
227 | sch_tree_lock(sch); |
228 | q->flags = ctl->flags; | |
1da177e4 | 229 | q->limit = ctl->limit; |
f38c39d6 PM |
230 | if (child) |
231 | qdisc_destroy(xchg(&q->qdisc, child)); | |
1da177e4 | 232 | |
6b31b28a TG |
233 | red_set_parms(&q->parms, ctl->qth_min, ctl->qth_max, ctl->Wlog, |
234 | ctl->Plog, ctl->Scell_log, | |
235 | RTA_DATA(tb[TCA_RED_STAB-1])); | |
236 | ||
b03efcfb | 237 | if (skb_queue_empty(&sch->q)) |
6b31b28a | 238 | red_end_of_idle_period(&q->parms); |
dba051f3 | 239 | |
1da177e4 LT |
240 | sch_tree_unlock(sch); |
241 | return 0; | |
242 | } | |
243 | ||
244 | static int red_init(struct Qdisc* sch, struct rtattr *opt) | |
245 | { | |
f38c39d6 PM |
246 | struct red_sched_data *q = qdisc_priv(sch); |
247 | ||
248 | q->qdisc = &noop_qdisc; | |
1da177e4 LT |
249 | return red_change(sch, opt); |
250 | } | |
251 | ||
252 | static int red_dump(struct Qdisc *sch, struct sk_buff *skb) | |
253 | { | |
254 | struct red_sched_data *q = qdisc_priv(sch); | |
dba051f3 | 255 | struct rtattr *opts = NULL; |
6b31b28a TG |
256 | struct tc_red_qopt opt = { |
257 | .limit = q->limit, | |
258 | .flags = q->flags, | |
259 | .qth_min = q->parms.qth_min >> q->parms.Wlog, | |
260 | .qth_max = q->parms.qth_max >> q->parms.Wlog, | |
261 | .Wlog = q->parms.Wlog, | |
262 | .Plog = q->parms.Plog, | |
263 | .Scell_log = q->parms.Scell_log, | |
264 | }; | |
1da177e4 | 265 | |
dba051f3 | 266 | opts = RTA_NEST(skb, TCA_OPTIONS); |
1da177e4 | 267 | RTA_PUT(skb, TCA_RED_PARMS, sizeof(opt), &opt); |
dba051f3 | 268 | return RTA_NEST_END(skb, opts); |
1da177e4 LT |
269 | |
270 | rtattr_failure: | |
dba051f3 | 271 | return RTA_NEST_CANCEL(skb, opts); |
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 | ||
292 | if (cl != 1) | |
293 | return -ENOENT; | |
294 | tcm->tcm_handle |= TC_H_MIN(1); | |
295 | tcm->tcm_info = q->qdisc->handle; | |
296 | return 0; | |
297 | } | |
298 | ||
299 | static int red_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, | |
300 | struct Qdisc **old) | |
301 | { | |
302 | struct red_sched_data *q = qdisc_priv(sch); | |
303 | ||
304 | if (new == NULL) | |
305 | new = &noop_qdisc; | |
306 | ||
307 | sch_tree_lock(sch); | |
308 | *old = xchg(&q->qdisc, new); | |
309 | qdisc_reset(*old); | |
310 | sch->q.qlen = 0; | |
311 | sch_tree_unlock(sch); | |
312 | return 0; | |
313 | } | |
314 | ||
315 | static struct Qdisc *red_leaf(struct Qdisc *sch, unsigned long arg) | |
316 | { | |
317 | struct red_sched_data *q = qdisc_priv(sch); | |
318 | return q->qdisc; | |
319 | } | |
320 | ||
321 | static unsigned long red_get(struct Qdisc *sch, u32 classid) | |
322 | { | |
323 | return 1; | |
324 | } | |
325 | ||
326 | static void red_put(struct Qdisc *sch, unsigned long arg) | |
327 | { | |
328 | return; | |
329 | } | |
330 | ||
331 | static int red_change_class(struct Qdisc *sch, u32 classid, u32 parentid, | |
332 | struct rtattr **tca, unsigned long *arg) | |
333 | { | |
334 | return -ENOSYS; | |
335 | } | |
336 | ||
337 | static int red_delete(struct Qdisc *sch, unsigned long cl) | |
338 | { | |
339 | return -ENOSYS; | |
340 | } | |
341 | ||
342 | static void red_walk(struct Qdisc *sch, struct qdisc_walker *walker) | |
343 | { | |
344 | if (!walker->stop) { | |
345 | if (walker->count >= walker->skip) | |
346 | if (walker->fn(sch, 1, walker) < 0) { | |
347 | walker->stop = 1; | |
348 | return; | |
349 | } | |
350 | walker->count++; | |
351 | } | |
352 | } | |
353 | ||
354 | static struct tcf_proto **red_find_tcf(struct Qdisc *sch, unsigned long cl) | |
355 | { | |
356 | return NULL; | |
357 | } | |
358 | ||
359 | static struct Qdisc_class_ops red_class_ops = { | |
360 | .graft = red_graft, | |
361 | .leaf = red_leaf, | |
362 | .get = red_get, | |
363 | .put = red_put, | |
364 | .change = red_change_class, | |
365 | .delete = red_delete, | |
366 | .walk = red_walk, | |
367 | .tcf_chain = red_find_tcf, | |
368 | .dump = red_dump_class, | |
369 | }; | |
370 | ||
1da177e4 | 371 | static struct Qdisc_ops red_qdisc_ops = { |
1da177e4 LT |
372 | .id = "red", |
373 | .priv_size = sizeof(struct red_sched_data), | |
f38c39d6 | 374 | .cl_ops = &red_class_ops, |
1da177e4 LT |
375 | .enqueue = red_enqueue, |
376 | .dequeue = red_dequeue, | |
377 | .requeue = red_requeue, | |
378 | .drop = red_drop, | |
379 | .init = red_init, | |
380 | .reset = red_reset, | |
f38c39d6 | 381 | .destroy = red_destroy, |
1da177e4 LT |
382 | .change = red_change, |
383 | .dump = red_dump, | |
384 | .dump_stats = red_dump_stats, | |
385 | .owner = THIS_MODULE, | |
386 | }; | |
387 | ||
388 | static int __init red_module_init(void) | |
389 | { | |
390 | return register_qdisc(&red_qdisc_ops); | |
391 | } | |
dba051f3 TG |
392 | |
393 | static void __exit red_module_exit(void) | |
1da177e4 LT |
394 | { |
395 | unregister_qdisc(&red_qdisc_ops); | |
396 | } | |
dba051f3 | 397 | |
1da177e4 LT |
398 | module_init(red_module_init) |
399 | module_exit(red_module_exit) | |
dba051f3 | 400 | |
1da177e4 | 401 | MODULE_LICENSE("GPL"); |