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1 /*
2 * net/sched/sch_prio.c Simple 3-band priority "scheduler".
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 * Fixes: 19990609: J Hadi Salim <hadi@nortelnetworks.com>:
11 * Init -- EINVAL when opt undefined
12 */
13
14 #include <linux/module.h>
15 #include <linux/slab.h>
16 #include <linux/types.h>
17 #include <linux/kernel.h>
18 #include <linux/string.h>
19 #include <linux/errno.h>
20 #include <linux/skbuff.h>
21 #include <net/netlink.h>
22 #include <net/pkt_sched.h>
23
24
25 struct prio_sched_data
26 {
27 int bands;
28 struct tcf_proto *filter_list;
29 u8 prio2band[TC_PRIO_MAX+1];
30 struct Qdisc *queues[TCQ_PRIO_BANDS];
31 };
32
33
34 static struct Qdisc *
35 prio_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
36 {
37 struct prio_sched_data *q = qdisc_priv(sch);
38 u32 band = skb->priority;
39 struct tcf_result res;
40 int err;
41
42 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
43 if (TC_H_MAJ(skb->priority) != sch->handle) {
44 err = tc_classify(skb, q->filter_list, &res);
45 #ifdef CONFIG_NET_CLS_ACT
46 switch (err) {
47 case TC_ACT_STOLEN:
48 case TC_ACT_QUEUED:
49 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
50 case TC_ACT_SHOT:
51 return NULL;
52 }
53 #endif
54 if (!q->filter_list || err < 0) {
55 if (TC_H_MAJ(band))
56 band = 0;
57 return q->queues[q->prio2band[band&TC_PRIO_MAX]];
58 }
59 band = res.classid;
60 }
61 band = TC_H_MIN(band) - 1;
62 if (band >= q->bands)
63 return q->queues[q->prio2band[0]];
64
65 return q->queues[band];
66 }
67
68 static int
69 prio_enqueue(struct sk_buff *skb, struct Qdisc *sch)
70 {
71 struct Qdisc *qdisc;
72 int ret;
73
74 qdisc = prio_classify(skb, sch, &ret);
75 #ifdef CONFIG_NET_CLS_ACT
76 if (qdisc == NULL) {
77
78 if (ret & __NET_XMIT_BYPASS)
79 sch->qstats.drops++;
80 kfree_skb(skb);
81 return ret;
82 }
83 #endif
84
85 ret = qdisc_enqueue(skb, qdisc);
86 if (ret == NET_XMIT_SUCCESS) {
87 sch->q.qlen++;
88 return NET_XMIT_SUCCESS;
89 }
90 if (net_xmit_drop_count(ret))
91 sch->qstats.drops++;
92 return ret;
93 }
94
95 static struct sk_buff *prio_peek(struct Qdisc *sch)
96 {
97 struct prio_sched_data *q = qdisc_priv(sch);
98 int prio;
99
100 for (prio = 0; prio < q->bands; prio++) {
101 struct Qdisc *qdisc = q->queues[prio];
102 struct sk_buff *skb = qdisc->ops->peek(qdisc);
103 if (skb)
104 return skb;
105 }
106 return NULL;
107 }
108
109 static struct sk_buff *prio_dequeue(struct Qdisc* sch)
110 {
111 struct prio_sched_data *q = qdisc_priv(sch);
112 int prio;
113
114 for (prio = 0; prio < q->bands; prio++) {
115 struct Qdisc *qdisc = q->queues[prio];
116 struct sk_buff *skb = qdisc->dequeue(qdisc);
117 if (skb) {
118 qdisc_bstats_update(sch, skb);
119 sch->q.qlen--;
120 return skb;
121 }
122 }
123 return NULL;
124
125 }
126
127 static unsigned int prio_drop(struct Qdisc* sch)
128 {
129 struct prio_sched_data *q = qdisc_priv(sch);
130 int prio;
131 unsigned int len;
132 struct Qdisc *qdisc;
133
134 for (prio = q->bands-1; prio >= 0; prio--) {
135 qdisc = q->queues[prio];
136 if (qdisc->ops->drop && (len = qdisc->ops->drop(qdisc)) != 0) {
137 sch->q.qlen--;
138 return len;
139 }
140 }
141 return 0;
142 }
143
144
145 static void
146 prio_reset(struct Qdisc* sch)
147 {
148 int prio;
149 struct prio_sched_data *q = qdisc_priv(sch);
150
151 for (prio=0; prio<q->bands; prio++)
152 qdisc_reset(q->queues[prio]);
153 sch->q.qlen = 0;
154 }
155
156 static void
157 prio_destroy(struct Qdisc* sch)
158 {
159 int prio;
160 struct prio_sched_data *q = qdisc_priv(sch);
161
162 tcf_destroy_chain(&q->filter_list);
163 for (prio=0; prio<q->bands; prio++)
164 qdisc_destroy(q->queues[prio]);
165 }
166
167 static int prio_tune(struct Qdisc *sch, struct nlattr *opt)
168 {
169 struct prio_sched_data *q = qdisc_priv(sch);
170 struct tc_prio_qopt *qopt;
171 int i;
172
173 if (nla_len(opt) < sizeof(*qopt))
174 return -EINVAL;
175 qopt = nla_data(opt);
176
177 if (qopt->bands > TCQ_PRIO_BANDS || qopt->bands < 2)
178 return -EINVAL;
179
180 for (i=0; i<=TC_PRIO_MAX; i++) {
181 if (qopt->priomap[i] >= qopt->bands)
182 return -EINVAL;
183 }
184
185 sch_tree_lock(sch);
186 q->bands = qopt->bands;
187 memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1);
188
189 for (i=q->bands; i<TCQ_PRIO_BANDS; i++) {
190 struct Qdisc *child = q->queues[i];
191 q->queues[i] = &noop_qdisc;
192 if (child != &noop_qdisc) {
193 qdisc_tree_decrease_qlen(child, child->q.qlen);
194 qdisc_destroy(child);
195 }
196 }
197 sch_tree_unlock(sch);
198
199 for (i=0; i<q->bands; i++) {
200 if (q->queues[i] == &noop_qdisc) {
201 struct Qdisc *child, *old;
202 child = qdisc_create_dflt(sch->dev_queue,
203 &pfifo_qdisc_ops,
204 TC_H_MAKE(sch->handle, i + 1));
205 if (child) {
206 sch_tree_lock(sch);
207 old = q->queues[i];
208 q->queues[i] = child;
209
210 if (old != &noop_qdisc) {
211 qdisc_tree_decrease_qlen(old,
212 old->q.qlen);
213 qdisc_destroy(old);
214 }
215 sch_tree_unlock(sch);
216 }
217 }
218 }
219 return 0;
220 }
221
222 static int prio_init(struct Qdisc *sch, struct nlattr *opt)
223 {
224 struct prio_sched_data *q = qdisc_priv(sch);
225 int i;
226
227 for (i=0; i<TCQ_PRIO_BANDS; i++)
228 q->queues[i] = &noop_qdisc;
229
230 if (opt == NULL) {
231 return -EINVAL;
232 } else {
233 int err;
234
235 if ((err= prio_tune(sch, opt)) != 0)
236 return err;
237 }
238 return 0;
239 }
240
241 static int prio_dump(struct Qdisc *sch, struct sk_buff *skb)
242 {
243 struct prio_sched_data *q = qdisc_priv(sch);
244 unsigned char *b = skb_tail_pointer(skb);
245 struct tc_prio_qopt opt;
246
247 opt.bands = q->bands;
248 memcpy(&opt.priomap, q->prio2band, TC_PRIO_MAX+1);
249
250 NLA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
251
252 return skb->len;
253
254 nla_put_failure:
255 nlmsg_trim(skb, b);
256 return -1;
257 }
258
259 static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
260 struct Qdisc **old)
261 {
262 struct prio_sched_data *q = qdisc_priv(sch);
263 unsigned long band = arg - 1;
264
265 if (new == NULL)
266 new = &noop_qdisc;
267
268 sch_tree_lock(sch);
269 *old = q->queues[band];
270 q->queues[band] = new;
271 qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
272 qdisc_reset(*old);
273 sch_tree_unlock(sch);
274
275 return 0;
276 }
277
278 static struct Qdisc *
279 prio_leaf(struct Qdisc *sch, unsigned long arg)
280 {
281 struct prio_sched_data *q = qdisc_priv(sch);
282 unsigned long band = arg - 1;
283
284 return q->queues[band];
285 }
286
287 static unsigned long prio_get(struct Qdisc *sch, u32 classid)
288 {
289 struct prio_sched_data *q = qdisc_priv(sch);
290 unsigned long band = TC_H_MIN(classid);
291
292 if (band - 1 >= q->bands)
293 return 0;
294 return band;
295 }
296
297 static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid)
298 {
299 return prio_get(sch, classid);
300 }
301
302
303 static void prio_put(struct Qdisc *q, unsigned long cl)
304 {
305 }
306
307 static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb,
308 struct tcmsg *tcm)
309 {
310 struct prio_sched_data *q = qdisc_priv(sch);
311
312 tcm->tcm_handle |= TC_H_MIN(cl);
313 tcm->tcm_info = q->queues[cl-1]->handle;
314 return 0;
315 }
316
317 static int prio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
318 struct gnet_dump *d)
319 {
320 struct prio_sched_data *q = qdisc_priv(sch);
321 struct Qdisc *cl_q;
322
323 cl_q = q->queues[cl - 1];
324 cl_q->qstats.qlen = cl_q->q.qlen;
325 if (gnet_stats_copy_basic(d, &cl_q->bstats) < 0 ||
326 gnet_stats_copy_queue(d, &cl_q->qstats) < 0)
327 return -1;
328
329 return 0;
330 }
331
332 static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
333 {
334 struct prio_sched_data *q = qdisc_priv(sch);
335 int prio;
336
337 if (arg->stop)
338 return;
339
340 for (prio = 0; prio < q->bands; prio++) {
341 if (arg->count < arg->skip) {
342 arg->count++;
343 continue;
344 }
345 if (arg->fn(sch, prio+1, arg) < 0) {
346 arg->stop = 1;
347 break;
348 }
349 arg->count++;
350 }
351 }
352
353 static struct tcf_proto ** prio_find_tcf(struct Qdisc *sch, unsigned long cl)
354 {
355 struct prio_sched_data *q = qdisc_priv(sch);
356
357 if (cl)
358 return NULL;
359 return &q->filter_list;
360 }
361
362 static const struct Qdisc_class_ops prio_class_ops = {
363 .graft = prio_graft,
364 .leaf = prio_leaf,
365 .get = prio_get,
366 .put = prio_put,
367 .walk = prio_walk,
368 .tcf_chain = prio_find_tcf,
369 .bind_tcf = prio_bind,
370 .unbind_tcf = prio_put,
371 .dump = prio_dump_class,
372 .dump_stats = prio_dump_class_stats,
373 };
374
375 static struct Qdisc_ops prio_qdisc_ops __read_mostly = {
376 .next = NULL,
377 .cl_ops = &prio_class_ops,
378 .id = "prio",
379 .priv_size = sizeof(struct prio_sched_data),
380 .enqueue = prio_enqueue,
381 .dequeue = prio_dequeue,
382 .peek = prio_peek,
383 .drop = prio_drop,
384 .init = prio_init,
385 .reset = prio_reset,
386 .destroy = prio_destroy,
387 .change = prio_tune,
388 .dump = prio_dump,
389 .owner = THIS_MODULE,
390 };
391
392 static int __init prio_module_init(void)
393 {
394 return register_qdisc(&prio_qdisc_ops);
395 }
396
397 static void __exit prio_module_exit(void)
398 {
399 unregister_qdisc(&prio_qdisc_ops);
400 }
401
402 module_init(prio_module_init)
403 module_exit(prio_module_exit)
404
405 MODULE_LICENSE("GPL");