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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * net/sched/sch_red.c Random Early Detection queue.
4 *
5 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
6 *
7 * Changes:
8 * J Hadi Salim 980914: computation fixes
9 * Alexey Makarenko <makar@phoenix.kharkov.ua> 990814: qave on idle link was calculated incorrectly.
10 * J Hadi Salim 980816: ECN support
11 */
12
13#include <linux/module.h>
14#include <linux/types.h>
15#include <linux/kernel.h>
16#include <linux/skbuff.h>
17#include <net/pkt_sched.h>
18#include <net/pkt_cls.h>
19#include <net/inet_ecn.h>
20#include <net/red.h>
21
22
23/* Parameters, settable by user:
24 -----------------------------
25
26 limit - bytes (must be > qth_max + burst)
27
28 Hard limit on queue length, should be chosen >qth_max
29 to allow packet bursts. This parameter does not
30 affect the algorithms behaviour and can be chosen
31 arbitrarily high (well, less than ram size)
32 Really, this limit will never be reached
33 if RED works correctly.
34 */
35
36struct red_sched_data {
37 u32 limit; /* HARD maximal queue length */
38 unsigned char flags;
39 struct timer_list adapt_timer;
40 struct Qdisc *sch;
41 struct red_parms parms;
42 struct red_vars vars;
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 struct sk_buff **to_free)
59{
60 struct red_sched_data *q = qdisc_priv(sch);
61 struct Qdisc *child = q->qdisc;
62 int ret;
63
64 q->vars.qavg = red_calc_qavg(&q->parms,
65 &q->vars,
66 child->qstats.backlog);
67
68 if (red_is_idling(&q->vars))
69 red_end_of_idle_period(&q->vars);
70
71 switch (red_action(&q->parms, &q->vars, q->vars.qavg)) {
72 case RED_DONT_MARK:
73 break;
74
75 case RED_PROB_MARK:
76 qdisc_qstats_overlimit(sch);
77 if (!red_use_ecn(q) || !INET_ECN_set_ce(skb)) {
78 q->stats.prob_drop++;
79 goto congestion_drop;
80 }
81
82 q->stats.prob_mark++;
83 break;
84
85 case RED_HARD_MARK:
86 qdisc_qstats_overlimit(sch);
87 if (red_use_harddrop(q) || !red_use_ecn(q) ||
88 !INET_ECN_set_ce(skb)) {
89 q->stats.forced_drop++;
90 goto congestion_drop;
91 }
92
93 q->stats.forced_mark++;
94 break;
95 }
96
97 ret = qdisc_enqueue(skb, child, to_free);
98 if (likely(ret == NET_XMIT_SUCCESS)) {
99 qdisc_qstats_backlog_inc(sch, skb);
100 sch->q.qlen++;
101 } else if (net_xmit_drop_count(ret)) {
102 q->stats.pdrop++;
103 qdisc_qstats_drop(sch);
104 }
105 return ret;
106
107congestion_drop:
108 qdisc_drop(skb, sch, to_free);
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 qdisc_qstats_backlog_dec(sch, skb);
122 sch->q.qlen--;
123 } else {
124 if (!red_is_idling(&q->vars))
125 red_start_of_idle_period(&q->vars);
126 }
127 return skb;
128}
129
130static struct sk_buff *red_peek(struct Qdisc *sch)
131{
132 struct red_sched_data *q = qdisc_priv(sch);
133 struct Qdisc *child = q->qdisc;
134
135 return child->ops->peek(child);
136}
137
138static void red_reset(struct Qdisc *sch)
139{
140 struct red_sched_data *q = qdisc_priv(sch);
141
142 qdisc_reset(q->qdisc);
143 sch->qstats.backlog = 0;
144 sch->q.qlen = 0;
145 red_restart(&q->vars);
146}
147
148static int red_offload(struct Qdisc *sch, bool enable)
149{
150 struct red_sched_data *q = qdisc_priv(sch);
151 struct net_device *dev = qdisc_dev(sch);
152 struct tc_red_qopt_offload opt = {
153 .handle = sch->handle,
154 .parent = sch->parent,
155 };
156
157 if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
158 return -EOPNOTSUPP;
159
160 if (enable) {
161 opt.command = TC_RED_REPLACE;
162 opt.set.min = q->parms.qth_min >> q->parms.Wlog;
163 opt.set.max = q->parms.qth_max >> q->parms.Wlog;
164 opt.set.probability = q->parms.max_P;
165 opt.set.limit = q->limit;
166 opt.set.is_ecn = red_use_ecn(q);
167 opt.set.is_harddrop = red_use_harddrop(q);
168 opt.set.qstats = &sch->qstats;
169 } else {
170 opt.command = TC_RED_DESTROY;
171 }
172
173 return dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_RED, &opt);
174}
175
176static void red_destroy(struct Qdisc *sch)
177{
178 struct red_sched_data *q = qdisc_priv(sch);
179
180 del_timer_sync(&q->adapt_timer);
181 red_offload(sch, false);
182 qdisc_put(q->qdisc);
183}
184
185static const struct nla_policy red_policy[TCA_RED_MAX + 1] = {
186 [TCA_RED_PARMS] = { .len = sizeof(struct tc_red_qopt) },
187 [TCA_RED_STAB] = { .len = RED_STAB_SIZE },
188 [TCA_RED_MAX_P] = { .type = NLA_U32 },
189};
190
191static int red_change(struct Qdisc *sch, struct nlattr *opt,
192 struct netlink_ext_ack *extack)
193{
194 struct Qdisc *old_child = NULL, *child = NULL;
195 struct red_sched_data *q = qdisc_priv(sch);
196 struct nlattr *tb[TCA_RED_MAX + 1];
197 struct tc_red_qopt *ctl;
198 int err;
199 u32 max_P;
200
201 if (opt == NULL)
202 return -EINVAL;
203
204 err = nla_parse_nested_deprecated(tb, TCA_RED_MAX, opt, red_policy,
205 NULL);
206 if (err < 0)
207 return err;
208
209 if (tb[TCA_RED_PARMS] == NULL ||
210 tb[TCA_RED_STAB] == NULL)
211 return -EINVAL;
212
213 max_P = tb[TCA_RED_MAX_P] ? nla_get_u32(tb[TCA_RED_MAX_P]) : 0;
214
215 ctl = nla_data(tb[TCA_RED_PARMS]);
216 if (!red_check_params(ctl->qth_min, ctl->qth_max, ctl->Wlog))
217 return -EINVAL;
218
219 if (ctl->limit > 0) {
220 child = fifo_create_dflt(sch, &bfifo_qdisc_ops, ctl->limit,
221 extack);
222 if (IS_ERR(child))
223 return PTR_ERR(child);
224
225 /* child is fifo, no need to check for noop_qdisc */
226 qdisc_hash_add(child, true);
227 }
228
229 sch_tree_lock(sch);
230 q->flags = ctl->flags;
231 q->limit = ctl->limit;
232 if (child) {
233 qdisc_tree_flush_backlog(q->qdisc);
234 old_child = q->qdisc;
235 q->qdisc = child;
236 }
237
238 red_set_parms(&q->parms,
239 ctl->qth_min, ctl->qth_max, ctl->Wlog,
240 ctl->Plog, ctl->Scell_log,
241 nla_data(tb[TCA_RED_STAB]),
242 max_P);
243 red_set_vars(&q->vars);
244
245 del_timer(&q->adapt_timer);
246 if (ctl->flags & TC_RED_ADAPTATIVE)
247 mod_timer(&q->adapt_timer, jiffies + HZ/2);
248
249 if (!q->qdisc->q.qlen)
250 red_start_of_idle_period(&q->vars);
251
252 sch_tree_unlock(sch);
253
254 red_offload(sch, true);
255
256 if (old_child)
257 qdisc_put(old_child);
258 return 0;
259}
260
261static inline void red_adaptative_timer(struct timer_list *t)
262{
263 struct red_sched_data *q = from_timer(q, t, adapt_timer);
264 struct Qdisc *sch = q->sch;
265 spinlock_t *root_lock = qdisc_lock(qdisc_root_sleeping(sch));
266
267 spin_lock(root_lock);
268 red_adaptative_algo(&q->parms, &q->vars);
269 mod_timer(&q->adapt_timer, jiffies + HZ/2);
270 spin_unlock(root_lock);
271}
272
273static int red_init(struct Qdisc *sch, struct nlattr *opt,
274 struct netlink_ext_ack *extack)
275{
276 struct red_sched_data *q = qdisc_priv(sch);
277
278 q->qdisc = &noop_qdisc;
279 q->sch = sch;
280 timer_setup(&q->adapt_timer, red_adaptative_timer, 0);
281 return red_change(sch, opt, extack);
282}
283
284static int red_dump_offload_stats(struct Qdisc *sch)
285{
286 struct tc_red_qopt_offload hw_stats = {
287 .command = TC_RED_STATS,
288 .handle = sch->handle,
289 .parent = sch->parent,
290 {
291 .stats.bstats = &sch->bstats,
292 .stats.qstats = &sch->qstats,
293 },
294 };
295
296 return qdisc_offload_dump_helper(sch, TC_SETUP_QDISC_RED, &hw_stats);
297}
298
299static int red_dump(struct Qdisc *sch, struct sk_buff *skb)
300{
301 struct red_sched_data *q = qdisc_priv(sch);
302 struct nlattr *opts = NULL;
303 struct tc_red_qopt opt = {
304 .limit = q->limit,
305 .flags = q->flags,
306 .qth_min = q->parms.qth_min >> q->parms.Wlog,
307 .qth_max = q->parms.qth_max >> q->parms.Wlog,
308 .Wlog = q->parms.Wlog,
309 .Plog = q->parms.Plog,
310 .Scell_log = q->parms.Scell_log,
311 };
312 int err;
313
314 err = red_dump_offload_stats(sch);
315 if (err)
316 goto nla_put_failure;
317
318 opts = nla_nest_start_noflag(skb, TCA_OPTIONS);
319 if (opts == NULL)
320 goto nla_put_failure;
321 if (nla_put(skb, TCA_RED_PARMS, sizeof(opt), &opt) ||
322 nla_put_u32(skb, TCA_RED_MAX_P, q->parms.max_P))
323 goto nla_put_failure;
324 return nla_nest_end(skb, opts);
325
326nla_put_failure:
327 nla_nest_cancel(skb, opts);
328 return -EMSGSIZE;
329}
330
331static int red_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
332{
333 struct red_sched_data *q = qdisc_priv(sch);
334 struct net_device *dev = qdisc_dev(sch);
335 struct tc_red_xstats st = {0};
336
337 if (sch->flags & TCQ_F_OFFLOADED) {
338 struct tc_red_qopt_offload hw_stats_request = {
339 .command = TC_RED_XSTATS,
340 .handle = sch->handle,
341 .parent = sch->parent,
342 {
343 .xstats = &q->stats,
344 },
345 };
346 dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_RED,
347 &hw_stats_request);
348 }
349 st.early = q->stats.prob_drop + q->stats.forced_drop;
350 st.pdrop = q->stats.pdrop;
351 st.other = q->stats.other;
352 st.marked = q->stats.prob_mark + q->stats.forced_mark;
353
354 return gnet_stats_copy_app(d, &st, sizeof(st));
355}
356
357static int red_dump_class(struct Qdisc *sch, unsigned long cl,
358 struct sk_buff *skb, struct tcmsg *tcm)
359{
360 struct red_sched_data *q = qdisc_priv(sch);
361
362 tcm->tcm_handle |= TC_H_MIN(1);
363 tcm->tcm_info = q->qdisc->handle;
364 return 0;
365}
366
367static void red_graft_offload(struct Qdisc *sch,
368 struct Qdisc *new, struct Qdisc *old,
369 struct netlink_ext_ack *extack)
370{
371 struct tc_red_qopt_offload graft_offload = {
372 .handle = sch->handle,
373 .parent = sch->parent,
374 .child_handle = new->handle,
375 .command = TC_RED_GRAFT,
376 };
377
378 qdisc_offload_graft_helper(qdisc_dev(sch), sch, new, old,
379 TC_SETUP_QDISC_RED, &graft_offload, extack);
380}
381
382static int red_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
383 struct Qdisc **old, struct netlink_ext_ack *extack)
384{
385 struct red_sched_data *q = qdisc_priv(sch);
386
387 if (new == NULL)
388 new = &noop_qdisc;
389
390 *old = qdisc_replace(sch, new, &q->qdisc);
391
392 red_graft_offload(sch, new, *old, extack);
393 return 0;
394}
395
396static struct Qdisc *red_leaf(struct Qdisc *sch, unsigned long arg)
397{
398 struct red_sched_data *q = qdisc_priv(sch);
399 return q->qdisc;
400}
401
402static unsigned long red_find(struct Qdisc *sch, u32 classid)
403{
404 return 1;
405}
406
407static void red_walk(struct Qdisc *sch, struct qdisc_walker *walker)
408{
409 if (!walker->stop) {
410 if (walker->count >= walker->skip)
411 if (walker->fn(sch, 1, walker) < 0) {
412 walker->stop = 1;
413 return;
414 }
415 walker->count++;
416 }
417}
418
419static const struct Qdisc_class_ops red_class_ops = {
420 .graft = red_graft,
421 .leaf = red_leaf,
422 .find = red_find,
423 .walk = red_walk,
424 .dump = red_dump_class,
425};
426
427static struct Qdisc_ops red_qdisc_ops __read_mostly = {
428 .id = "red",
429 .priv_size = sizeof(struct red_sched_data),
430 .cl_ops = &red_class_ops,
431 .enqueue = red_enqueue,
432 .dequeue = red_dequeue,
433 .peek = red_peek,
434 .init = red_init,
435 .reset = red_reset,
436 .destroy = red_destroy,
437 .change = red_change,
438 .dump = red_dump,
439 .dump_stats = red_dump_stats,
440 .owner = THIS_MODULE,
441};
442
443static int __init red_module_init(void)
444{
445 return register_qdisc(&red_qdisc_ops);
446}
447
448static void __exit red_module_exit(void)
449{
450 unregister_qdisc(&red_qdisc_ops);
451}
452
453module_init(red_module_init)
454module_exit(red_module_exit)
455
456MODULE_LICENSE("GPL");
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * net/sched/sch_red.c Random Early Detection queue.
4 *
5 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
6 *
7 * Changes:
8 * J Hadi Salim 980914: computation fixes
9 * Alexey Makarenko <makar@phoenix.kharkov.ua> 990814: qave on idle link was calculated incorrectly.
10 * J Hadi Salim 980816: ECN support
11 */
12
13#include <linux/module.h>
14#include <linux/types.h>
15#include <linux/kernel.h>
16#include <linux/skbuff.h>
17#include <net/pkt_sched.h>
18#include <net/pkt_cls.h>
19#include <net/inet_ecn.h>
20#include <net/red.h>
21
22
23/* Parameters, settable by user:
24 -----------------------------
25
26 limit - bytes (must be > qth_max + burst)
27
28 Hard limit on queue length, should be chosen >qth_max
29 to allow packet bursts. This parameter does not
30 affect the algorithms behaviour and can be chosen
31 arbitrarily high (well, less than ram size)
32 Really, this limit will never be reached
33 if RED works correctly.
34 */
35
36struct red_sched_data {
37 u32 limit; /* HARD maximal queue length */
38
39 unsigned char flags;
40 /* Non-flags in tc_red_qopt.flags. */
41 unsigned char userbits;
42
43 struct timer_list adapt_timer;
44 struct Qdisc *sch;
45 struct red_parms parms;
46 struct red_vars vars;
47 struct red_stats stats;
48 struct Qdisc *qdisc;
49 struct tcf_qevent qe_early_drop;
50 struct tcf_qevent qe_mark;
51};
52
53#define TC_RED_SUPPORTED_FLAGS (TC_RED_HISTORIC_FLAGS | TC_RED_NODROP)
54
55static inline int red_use_ecn(struct red_sched_data *q)
56{
57 return q->flags & TC_RED_ECN;
58}
59
60static inline int red_use_harddrop(struct red_sched_data *q)
61{
62 return q->flags & TC_RED_HARDDROP;
63}
64
65static int red_use_nodrop(struct red_sched_data *q)
66{
67 return q->flags & TC_RED_NODROP;
68}
69
70static int red_enqueue(struct sk_buff *skb, struct Qdisc *sch,
71 struct sk_buff **to_free)
72{
73 struct red_sched_data *q = qdisc_priv(sch);
74 struct Qdisc *child = q->qdisc;
75 unsigned int len;
76 int ret;
77
78 q->vars.qavg = red_calc_qavg(&q->parms,
79 &q->vars,
80 child->qstats.backlog);
81
82 if (red_is_idling(&q->vars))
83 red_end_of_idle_period(&q->vars);
84
85 switch (red_action(&q->parms, &q->vars, q->vars.qavg)) {
86 case RED_DONT_MARK:
87 break;
88
89 case RED_PROB_MARK:
90 qdisc_qstats_overlimit(sch);
91 if (!red_use_ecn(q)) {
92 q->stats.prob_drop++;
93 goto congestion_drop;
94 }
95
96 if (INET_ECN_set_ce(skb)) {
97 q->stats.prob_mark++;
98 skb = tcf_qevent_handle(&q->qe_mark, sch, skb, to_free, &ret);
99 if (!skb)
100 return NET_XMIT_CN | ret;
101 } else if (!red_use_nodrop(q)) {
102 q->stats.prob_drop++;
103 goto congestion_drop;
104 }
105
106 /* Non-ECT packet in ECN nodrop mode: queue it. */
107 break;
108
109 case RED_HARD_MARK:
110 qdisc_qstats_overlimit(sch);
111 if (red_use_harddrop(q) || !red_use_ecn(q)) {
112 q->stats.forced_drop++;
113 goto congestion_drop;
114 }
115
116 if (INET_ECN_set_ce(skb)) {
117 q->stats.forced_mark++;
118 skb = tcf_qevent_handle(&q->qe_mark, sch, skb, to_free, &ret);
119 if (!skb)
120 return NET_XMIT_CN | ret;
121 } else if (!red_use_nodrop(q)) {
122 q->stats.forced_drop++;
123 goto congestion_drop;
124 }
125
126 /* Non-ECT packet in ECN nodrop mode: queue it. */
127 break;
128 }
129
130 len = qdisc_pkt_len(skb);
131 ret = qdisc_enqueue(skb, child, to_free);
132 if (likely(ret == NET_XMIT_SUCCESS)) {
133 sch->qstats.backlog += len;
134 sch->q.qlen++;
135 } else if (net_xmit_drop_count(ret)) {
136 q->stats.pdrop++;
137 qdisc_qstats_drop(sch);
138 }
139 return ret;
140
141congestion_drop:
142 skb = tcf_qevent_handle(&q->qe_early_drop, sch, skb, to_free, &ret);
143 if (!skb)
144 return NET_XMIT_CN | ret;
145
146 qdisc_drop(skb, sch, to_free);
147 return NET_XMIT_CN;
148}
149
150static struct sk_buff *red_dequeue(struct Qdisc *sch)
151{
152 struct sk_buff *skb;
153 struct red_sched_data *q = qdisc_priv(sch);
154 struct Qdisc *child = q->qdisc;
155
156 skb = child->dequeue(child);
157 if (skb) {
158 qdisc_bstats_update(sch, skb);
159 qdisc_qstats_backlog_dec(sch, skb);
160 sch->q.qlen--;
161 } else {
162 if (!red_is_idling(&q->vars))
163 red_start_of_idle_period(&q->vars);
164 }
165 return skb;
166}
167
168static struct sk_buff *red_peek(struct Qdisc *sch)
169{
170 struct red_sched_data *q = qdisc_priv(sch);
171 struct Qdisc *child = q->qdisc;
172
173 return child->ops->peek(child);
174}
175
176static void red_reset(struct Qdisc *sch)
177{
178 struct red_sched_data *q = qdisc_priv(sch);
179
180 qdisc_reset(q->qdisc);
181 red_restart(&q->vars);
182}
183
184static int red_offload(struct Qdisc *sch, bool enable)
185{
186 struct red_sched_data *q = qdisc_priv(sch);
187 struct net_device *dev = qdisc_dev(sch);
188 struct tc_red_qopt_offload opt = {
189 .handle = sch->handle,
190 .parent = sch->parent,
191 };
192
193 if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
194 return -EOPNOTSUPP;
195
196 if (enable) {
197 opt.command = TC_RED_REPLACE;
198 opt.set.min = q->parms.qth_min >> q->parms.Wlog;
199 opt.set.max = q->parms.qth_max >> q->parms.Wlog;
200 opt.set.probability = q->parms.max_P;
201 opt.set.limit = q->limit;
202 opt.set.is_ecn = red_use_ecn(q);
203 opt.set.is_harddrop = red_use_harddrop(q);
204 opt.set.is_nodrop = red_use_nodrop(q);
205 opt.set.qstats = &sch->qstats;
206 } else {
207 opt.command = TC_RED_DESTROY;
208 }
209
210 return dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_RED, &opt);
211}
212
213static void red_destroy(struct Qdisc *sch)
214{
215 struct red_sched_data *q = qdisc_priv(sch);
216
217 tcf_qevent_destroy(&q->qe_mark, sch);
218 tcf_qevent_destroy(&q->qe_early_drop, sch);
219 del_timer_sync(&q->adapt_timer);
220 red_offload(sch, false);
221 qdisc_put(q->qdisc);
222}
223
224static const struct nla_policy red_policy[TCA_RED_MAX + 1] = {
225 [TCA_RED_UNSPEC] = { .strict_start_type = TCA_RED_FLAGS },
226 [TCA_RED_PARMS] = { .len = sizeof(struct tc_red_qopt) },
227 [TCA_RED_STAB] = { .len = RED_STAB_SIZE },
228 [TCA_RED_MAX_P] = { .type = NLA_U32 },
229 [TCA_RED_FLAGS] = NLA_POLICY_BITFIELD32(TC_RED_SUPPORTED_FLAGS),
230 [TCA_RED_EARLY_DROP_BLOCK] = { .type = NLA_U32 },
231 [TCA_RED_MARK_BLOCK] = { .type = NLA_U32 },
232};
233
234static int __red_change(struct Qdisc *sch, struct nlattr **tb,
235 struct netlink_ext_ack *extack)
236{
237 struct Qdisc *old_child = NULL, *child = NULL;
238 struct red_sched_data *q = qdisc_priv(sch);
239 struct nla_bitfield32 flags_bf;
240 struct tc_red_qopt *ctl;
241 unsigned char userbits;
242 unsigned char flags;
243 int err;
244 u32 max_P;
245 u8 *stab;
246
247 if (tb[TCA_RED_PARMS] == NULL ||
248 tb[TCA_RED_STAB] == NULL)
249 return -EINVAL;
250
251 max_P = tb[TCA_RED_MAX_P] ? nla_get_u32(tb[TCA_RED_MAX_P]) : 0;
252
253 ctl = nla_data(tb[TCA_RED_PARMS]);
254 stab = nla_data(tb[TCA_RED_STAB]);
255 if (!red_check_params(ctl->qth_min, ctl->qth_max, ctl->Wlog,
256 ctl->Scell_log, stab))
257 return -EINVAL;
258
259 err = red_get_flags(ctl->flags, TC_RED_HISTORIC_FLAGS,
260 tb[TCA_RED_FLAGS], TC_RED_SUPPORTED_FLAGS,
261 &flags_bf, &userbits, extack);
262 if (err)
263 return err;
264
265 if (ctl->limit > 0) {
266 child = fifo_create_dflt(sch, &bfifo_qdisc_ops, ctl->limit,
267 extack);
268 if (IS_ERR(child))
269 return PTR_ERR(child);
270
271 /* child is fifo, no need to check for noop_qdisc */
272 qdisc_hash_add(child, true);
273 }
274
275 sch_tree_lock(sch);
276
277 flags = (q->flags & ~flags_bf.selector) | flags_bf.value;
278 err = red_validate_flags(flags, extack);
279 if (err)
280 goto unlock_out;
281
282 q->flags = flags;
283 q->userbits = userbits;
284 q->limit = ctl->limit;
285 if (child) {
286 qdisc_tree_flush_backlog(q->qdisc);
287 old_child = q->qdisc;
288 q->qdisc = child;
289 }
290
291 red_set_parms(&q->parms,
292 ctl->qth_min, ctl->qth_max, ctl->Wlog,
293 ctl->Plog, ctl->Scell_log,
294 stab,
295 max_P);
296 red_set_vars(&q->vars);
297
298 del_timer(&q->adapt_timer);
299 if (ctl->flags & TC_RED_ADAPTATIVE)
300 mod_timer(&q->adapt_timer, jiffies + HZ/2);
301
302 if (!q->qdisc->q.qlen)
303 red_start_of_idle_period(&q->vars);
304
305 sch_tree_unlock(sch);
306
307 red_offload(sch, true);
308
309 if (old_child)
310 qdisc_put(old_child);
311 return 0;
312
313unlock_out:
314 sch_tree_unlock(sch);
315 if (child)
316 qdisc_put(child);
317 return err;
318}
319
320static inline void red_adaptative_timer(struct timer_list *t)
321{
322 struct red_sched_data *q = from_timer(q, t, adapt_timer);
323 struct Qdisc *sch = q->sch;
324 spinlock_t *root_lock;
325
326 rcu_read_lock();
327 root_lock = qdisc_lock(qdisc_root_sleeping(sch));
328 spin_lock(root_lock);
329 red_adaptative_algo(&q->parms, &q->vars);
330 mod_timer(&q->adapt_timer, jiffies + HZ/2);
331 spin_unlock(root_lock);
332 rcu_read_unlock();
333}
334
335static int red_init(struct Qdisc *sch, struct nlattr *opt,
336 struct netlink_ext_ack *extack)
337{
338 struct red_sched_data *q = qdisc_priv(sch);
339 struct nlattr *tb[TCA_RED_MAX + 1];
340 int err;
341
342 q->qdisc = &noop_qdisc;
343 q->sch = sch;
344 timer_setup(&q->adapt_timer, red_adaptative_timer, 0);
345
346 if (!opt)
347 return -EINVAL;
348
349 err = nla_parse_nested_deprecated(tb, TCA_RED_MAX, opt, red_policy,
350 extack);
351 if (err < 0)
352 return err;
353
354 err = __red_change(sch, tb, extack);
355 if (err)
356 return err;
357
358 err = tcf_qevent_init(&q->qe_early_drop, sch,
359 FLOW_BLOCK_BINDER_TYPE_RED_EARLY_DROP,
360 tb[TCA_RED_EARLY_DROP_BLOCK], extack);
361 if (err)
362 return err;
363
364 return tcf_qevent_init(&q->qe_mark, sch,
365 FLOW_BLOCK_BINDER_TYPE_RED_MARK,
366 tb[TCA_RED_MARK_BLOCK], extack);
367}
368
369static int red_change(struct Qdisc *sch, struct nlattr *opt,
370 struct netlink_ext_ack *extack)
371{
372 struct red_sched_data *q = qdisc_priv(sch);
373 struct nlattr *tb[TCA_RED_MAX + 1];
374 int err;
375
376 err = nla_parse_nested_deprecated(tb, TCA_RED_MAX, opt, red_policy,
377 extack);
378 if (err < 0)
379 return err;
380
381 err = tcf_qevent_validate_change(&q->qe_early_drop,
382 tb[TCA_RED_EARLY_DROP_BLOCK], extack);
383 if (err)
384 return err;
385
386 err = tcf_qevent_validate_change(&q->qe_mark,
387 tb[TCA_RED_MARK_BLOCK], extack);
388 if (err)
389 return err;
390
391 return __red_change(sch, tb, extack);
392}
393
394static int red_dump_offload_stats(struct Qdisc *sch)
395{
396 struct tc_red_qopt_offload hw_stats = {
397 .command = TC_RED_STATS,
398 .handle = sch->handle,
399 .parent = sch->parent,
400 {
401 .stats.bstats = &sch->bstats,
402 .stats.qstats = &sch->qstats,
403 },
404 };
405
406 return qdisc_offload_dump_helper(sch, TC_SETUP_QDISC_RED, &hw_stats);
407}
408
409static int red_dump(struct Qdisc *sch, struct sk_buff *skb)
410{
411 struct red_sched_data *q = qdisc_priv(sch);
412 struct nlattr *opts = NULL;
413 struct tc_red_qopt opt = {
414 .limit = q->limit,
415 .flags = (q->flags & TC_RED_HISTORIC_FLAGS) |
416 q->userbits,
417 .qth_min = q->parms.qth_min >> q->parms.Wlog,
418 .qth_max = q->parms.qth_max >> q->parms.Wlog,
419 .Wlog = q->parms.Wlog,
420 .Plog = q->parms.Plog,
421 .Scell_log = q->parms.Scell_log,
422 };
423 int err;
424
425 err = red_dump_offload_stats(sch);
426 if (err)
427 goto nla_put_failure;
428
429 opts = nla_nest_start_noflag(skb, TCA_OPTIONS);
430 if (opts == NULL)
431 goto nla_put_failure;
432 if (nla_put(skb, TCA_RED_PARMS, sizeof(opt), &opt) ||
433 nla_put_u32(skb, TCA_RED_MAX_P, q->parms.max_P) ||
434 nla_put_bitfield32(skb, TCA_RED_FLAGS,
435 q->flags, TC_RED_SUPPORTED_FLAGS) ||
436 tcf_qevent_dump(skb, TCA_RED_MARK_BLOCK, &q->qe_mark) ||
437 tcf_qevent_dump(skb, TCA_RED_EARLY_DROP_BLOCK, &q->qe_early_drop))
438 goto nla_put_failure;
439 return nla_nest_end(skb, opts);
440
441nla_put_failure:
442 nla_nest_cancel(skb, opts);
443 return -EMSGSIZE;
444}
445
446static int red_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
447{
448 struct red_sched_data *q = qdisc_priv(sch);
449 struct net_device *dev = qdisc_dev(sch);
450 struct tc_red_xstats st = {0};
451
452 if (sch->flags & TCQ_F_OFFLOADED) {
453 struct tc_red_qopt_offload hw_stats_request = {
454 .command = TC_RED_XSTATS,
455 .handle = sch->handle,
456 .parent = sch->parent,
457 {
458 .xstats = &q->stats,
459 },
460 };
461 dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_RED,
462 &hw_stats_request);
463 }
464 st.early = q->stats.prob_drop + q->stats.forced_drop;
465 st.pdrop = q->stats.pdrop;
466 st.marked = q->stats.prob_mark + q->stats.forced_mark;
467
468 return gnet_stats_copy_app(d, &st, sizeof(st));
469}
470
471static int red_dump_class(struct Qdisc *sch, unsigned long cl,
472 struct sk_buff *skb, struct tcmsg *tcm)
473{
474 struct red_sched_data *q = qdisc_priv(sch);
475
476 tcm->tcm_handle |= TC_H_MIN(1);
477 tcm->tcm_info = q->qdisc->handle;
478 return 0;
479}
480
481static void red_graft_offload(struct Qdisc *sch,
482 struct Qdisc *new, struct Qdisc *old,
483 struct netlink_ext_ack *extack)
484{
485 struct tc_red_qopt_offload graft_offload = {
486 .handle = sch->handle,
487 .parent = sch->parent,
488 .child_handle = new->handle,
489 .command = TC_RED_GRAFT,
490 };
491
492 qdisc_offload_graft_helper(qdisc_dev(sch), sch, new, old,
493 TC_SETUP_QDISC_RED, &graft_offload, extack);
494}
495
496static int red_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
497 struct Qdisc **old, struct netlink_ext_ack *extack)
498{
499 struct red_sched_data *q = qdisc_priv(sch);
500
501 if (new == NULL)
502 new = &noop_qdisc;
503
504 *old = qdisc_replace(sch, new, &q->qdisc);
505
506 red_graft_offload(sch, new, *old, extack);
507 return 0;
508}
509
510static struct Qdisc *red_leaf(struct Qdisc *sch, unsigned long arg)
511{
512 struct red_sched_data *q = qdisc_priv(sch);
513 return q->qdisc;
514}
515
516static unsigned long red_find(struct Qdisc *sch, u32 classid)
517{
518 return 1;
519}
520
521static void red_walk(struct Qdisc *sch, struct qdisc_walker *walker)
522{
523 if (!walker->stop) {
524 tc_qdisc_stats_dump(sch, 1, walker);
525 }
526}
527
528static const struct Qdisc_class_ops red_class_ops = {
529 .graft = red_graft,
530 .leaf = red_leaf,
531 .find = red_find,
532 .walk = red_walk,
533 .dump = red_dump_class,
534};
535
536static struct Qdisc_ops red_qdisc_ops __read_mostly = {
537 .id = "red",
538 .priv_size = sizeof(struct red_sched_data),
539 .cl_ops = &red_class_ops,
540 .enqueue = red_enqueue,
541 .dequeue = red_dequeue,
542 .peek = red_peek,
543 .init = red_init,
544 .reset = red_reset,
545 .destroy = red_destroy,
546 .change = red_change,
547 .dump = red_dump,
548 .dump_stats = red_dump_stats,
549 .owner = THIS_MODULE,
550};
551
552static int __init red_module_init(void)
553{
554 return register_qdisc(&red_qdisc_ops);
555}
556
557static void __exit red_module_exit(void)
558{
559 unregister_qdisc(&red_qdisc_ops);
560}
561
562module_init(red_module_init)
563module_exit(red_module_exit)
564
565MODULE_LICENSE("GPL");
566MODULE_DESCRIPTION("Random Early Detection qdisc");