Merge git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild
[linux-2.6] / net / sched / sch_gred.c
1 /*
2  * net/sched/sch_gred.c Generic Random Early Detection queue.
3  *
4  *
5  *              This program is free software; you can redistribute it and/or
6  *              modify it under the terms of the GNU General Public License
7  *              as published by the Free Software Foundation; either version
8  *              2 of the License, or (at your option) any later version.
9  *
10  * Authors:    J Hadi Salim (hadi@cyberus.ca) 1998-2002
11  *
12  *             991129: -  Bug fix with grio mode
13  *                     - a better sing. AvgQ mode with Grio(WRED)
14  *                     - A finer grained VQ dequeue based on sugestion
15  *                       from Ren Liu
16  *                     - More error checks
17  *
18  *  For all the glorious comments look at include/net/red.h
19  */
20
21 #include <linux/module.h>
22 #include <linux/types.h>
23 #include <linux/kernel.h>
24 #include <linux/netdevice.h>
25 #include <linux/skbuff.h>
26 #include <net/pkt_sched.h>
27 #include <net/red.h>
28
29 #define GRED_DEF_PRIO (MAX_DPs / 2)
30 #define GRED_VQ_MASK (MAX_DPs - 1)
31
32 struct gred_sched_data;
33 struct gred_sched;
34
35 struct gred_sched_data
36 {
37         u32             limit;          /* HARD maximal queue length    */
38         u32             DP;             /* the drop pramaters */
39         u32             bytesin;        /* bytes seen on virtualQ so far*/
40         u32             packetsin;      /* packets seen on virtualQ so far*/
41         u32             backlog;        /* bytes on the virtualQ */
42         u8              prio;           /* the prio of this vq */
43
44         struct red_parms parms;
45         struct red_stats stats;
46 };
47
48 enum {
49         GRED_WRED_MODE = 1,
50         GRED_RIO_MODE,
51 };
52
53 struct gred_sched
54 {
55         struct gred_sched_data *tab[MAX_DPs];
56         unsigned long   flags;
57         u32             red_flags;
58         u32             DPs;
59         u32             def;
60         struct red_parms wred_set;
61 };
62
63 static inline int gred_wred_mode(struct gred_sched *table)
64 {
65         return test_bit(GRED_WRED_MODE, &table->flags);
66 }
67
68 static inline void gred_enable_wred_mode(struct gred_sched *table)
69 {
70         __set_bit(GRED_WRED_MODE, &table->flags);
71 }
72
73 static inline void gred_disable_wred_mode(struct gred_sched *table)
74 {
75         __clear_bit(GRED_WRED_MODE, &table->flags);
76 }
77
78 static inline int gred_rio_mode(struct gred_sched *table)
79 {
80         return test_bit(GRED_RIO_MODE, &table->flags);
81 }
82
83 static inline void gred_enable_rio_mode(struct gred_sched *table)
84 {
85         __set_bit(GRED_RIO_MODE, &table->flags);
86 }
87
88 static inline void gred_disable_rio_mode(struct gred_sched *table)
89 {
90         __clear_bit(GRED_RIO_MODE, &table->flags);
91 }
92
93 static inline int gred_wred_mode_check(struct Qdisc *sch)
94 {
95         struct gred_sched *table = qdisc_priv(sch);
96         int i;
97
98         /* Really ugly O(n^2) but shouldn't be necessary too frequent. */
99         for (i = 0; i < table->DPs; i++) {
100                 struct gred_sched_data *q = table->tab[i];
101                 int n;
102
103                 if (q == NULL)
104                         continue;
105
106                 for (n = 0; n < table->DPs; n++)
107                         if (table->tab[n] && table->tab[n] != q &&
108                             table->tab[n]->prio == q->prio)
109                                 return 1;
110         }
111
112         return 0;
113 }
114
115 static inline unsigned int gred_backlog(struct gred_sched *table,
116                                         struct gred_sched_data *q,
117                                         struct Qdisc *sch)
118 {
119         if (gred_wred_mode(table))
120                 return sch->qstats.backlog;
121         else
122                 return q->backlog;
123 }
124
125 static inline u16 tc_index_to_dp(struct sk_buff *skb)
126 {
127         return skb->tc_index & GRED_VQ_MASK;
128 }
129
130 static inline void gred_load_wred_set(struct gred_sched *table,
131                                       struct gred_sched_data *q)
132 {
133         q->parms.qavg = table->wred_set.qavg;
134         q->parms.qidlestart = table->wred_set.qidlestart;
135 }
136
137 static inline void gred_store_wred_set(struct gred_sched *table,
138                                        struct gred_sched_data *q)
139 {
140         table->wred_set.qavg = q->parms.qavg;
141 }
142
143 static inline int gred_use_ecn(struct gred_sched *t)
144 {
145         return t->red_flags & TC_RED_ECN;
146 }
147
148 static inline int gred_use_harddrop(struct gred_sched *t)
149 {
150         return t->red_flags & TC_RED_HARDDROP;
151 }
152
153 static int gred_enqueue(struct sk_buff *skb, struct Qdisc* sch)
154 {
155         struct gred_sched_data *q=NULL;
156         struct gred_sched *t= qdisc_priv(sch);
157         unsigned long qavg = 0;
158         u16 dp = tc_index_to_dp(skb);
159
160         if (dp >= t->DPs  || (q = t->tab[dp]) == NULL) {
161                 dp = t->def;
162
163                 if ((q = t->tab[dp]) == NULL) {
164                         /* Pass through packets not assigned to a DP
165                          * if no default DP has been configured. This
166                          * allows for DP flows to be left untouched.
167                          */
168                         if (skb_queue_len(&sch->q) < sch->dev->tx_queue_len)
169                                 return qdisc_enqueue_tail(skb, sch);
170                         else
171                                 goto drop;
172                 }
173
174                 /* fix tc_index? --could be controvesial but needed for
175                    requeueing */
176                 skb->tc_index = (skb->tc_index & ~GRED_VQ_MASK) | dp;
177         }
178
179         /* sum up all the qaves of prios <= to ours to get the new qave */
180         if (!gred_wred_mode(t) && gred_rio_mode(t)) {
181                 int i;
182
183                 for (i = 0; i < t->DPs; i++) {
184                         if (t->tab[i] && t->tab[i]->prio < q->prio &&
185                             !red_is_idling(&t->tab[i]->parms))
186                                 qavg +=t->tab[i]->parms.qavg;
187                 }
188
189         }
190
191         q->packetsin++;
192         q->bytesin += skb->len;
193
194         if (gred_wred_mode(t))
195                 gred_load_wred_set(t, q);
196
197         q->parms.qavg = red_calc_qavg(&q->parms, gred_backlog(t, q, sch));
198
199         if (red_is_idling(&q->parms))
200                 red_end_of_idle_period(&q->parms);
201
202         if (gred_wred_mode(t))
203                 gred_store_wred_set(t, q);
204
205         switch (red_action(&q->parms, q->parms.qavg + qavg)) {
206                 case RED_DONT_MARK:
207                         break;
208
209                 case RED_PROB_MARK:
210                         sch->qstats.overlimits++;
211                         if (!gred_use_ecn(t) || !INET_ECN_set_ce(skb)) {
212                                 q->stats.prob_drop++;
213                                 goto congestion_drop;
214                         }
215
216                         q->stats.prob_mark++;
217                         break;
218
219                 case RED_HARD_MARK:
220                         sch->qstats.overlimits++;
221                         if (gred_use_harddrop(t) || !gred_use_ecn(t) ||
222                             !INET_ECN_set_ce(skb)) {
223                                 q->stats.forced_drop++;
224                                 goto congestion_drop;
225                         }
226                         q->stats.forced_mark++;
227                         break;
228         }
229
230         if (q->backlog + skb->len <= q->limit) {
231                 q->backlog += skb->len;
232                 return qdisc_enqueue_tail(skb, sch);
233         }
234
235         q->stats.pdrop++;
236 drop:
237         return qdisc_drop(skb, sch);
238
239 congestion_drop:
240         qdisc_drop(skb, sch);
241         return NET_XMIT_CN;
242 }
243
244 static int gred_requeue(struct sk_buff *skb, struct Qdisc* sch)
245 {
246         struct gred_sched *t = qdisc_priv(sch);
247         struct gred_sched_data *q;
248         u16 dp = tc_index_to_dp(skb);
249
250         if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
251                 if (net_ratelimit())
252                         printk(KERN_WARNING "GRED: Unable to relocate VQ 0x%x "
253                                "for requeue, screwing up backlog.\n",
254                                tc_index_to_dp(skb));
255         } else {
256                 if (red_is_idling(&q->parms))
257                         red_end_of_idle_period(&q->parms);
258                 q->backlog += skb->len;
259         }
260
261         return qdisc_requeue(skb, sch);
262 }
263
264 static struct sk_buff *gred_dequeue(struct Qdisc* sch)
265 {
266         struct sk_buff *skb;
267         struct gred_sched *t = qdisc_priv(sch);
268
269         skb = qdisc_dequeue_head(sch);
270
271         if (skb) {
272                 struct gred_sched_data *q;
273                 u16 dp = tc_index_to_dp(skb);
274
275                 if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
276                         if (net_ratelimit())
277                                 printk(KERN_WARNING "GRED: Unable to relocate "
278                                        "VQ 0x%x after dequeue, screwing up "
279                                        "backlog.\n", tc_index_to_dp(skb));
280                 } else {
281                         q->backlog -= skb->len;
282
283                         if (!q->backlog && !gred_wred_mode(t))
284                                 red_start_of_idle_period(&q->parms);
285                 }
286
287                 return skb;
288         }
289
290         if (gred_wred_mode(t) && !red_is_idling(&t->wred_set))
291                 red_start_of_idle_period(&t->wred_set);
292
293         return NULL;
294 }
295
296 static unsigned int gred_drop(struct Qdisc* sch)
297 {
298         struct sk_buff *skb;
299         struct gred_sched *t = qdisc_priv(sch);
300
301         skb = qdisc_dequeue_tail(sch);
302         if (skb) {
303                 unsigned int len = skb->len;
304                 struct gred_sched_data *q;
305                 u16 dp = tc_index_to_dp(skb);
306
307                 if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
308                         if (net_ratelimit())
309                                 printk(KERN_WARNING "GRED: Unable to relocate "
310                                        "VQ 0x%x while dropping, screwing up "
311                                        "backlog.\n", tc_index_to_dp(skb));
312                 } else {
313                         q->backlog -= len;
314                         q->stats.other++;
315
316                         if (!q->backlog && !gred_wred_mode(t))
317                                 red_start_of_idle_period(&q->parms);
318                 }
319
320                 qdisc_drop(skb, sch);
321                 return len;
322         }
323
324         if (gred_wred_mode(t) && !red_is_idling(&t->wred_set))
325                 red_start_of_idle_period(&t->wred_set);
326
327         return 0;
328
329 }
330
331 static void gred_reset(struct Qdisc* sch)
332 {
333         int i;
334         struct gred_sched *t = qdisc_priv(sch);
335
336         qdisc_reset_queue(sch);
337
338         for (i = 0; i < t->DPs; i++) {
339                 struct gred_sched_data *q = t->tab[i];
340
341                 if (!q)
342                         continue;
343
344                 red_restart(&q->parms);
345                 q->backlog = 0;
346         }
347 }
348
349 static inline void gred_destroy_vq(struct gred_sched_data *q)
350 {
351         kfree(q);
352 }
353
354 static inline int gred_change_table_def(struct Qdisc *sch, struct rtattr *dps)
355 {
356         struct gred_sched *table = qdisc_priv(sch);
357         struct tc_gred_sopt *sopt;
358         int i;
359
360         if (dps == NULL || RTA_PAYLOAD(dps) < sizeof(*sopt))
361                 return -EINVAL;
362
363         sopt = RTA_DATA(dps);
364
365         if (sopt->DPs > MAX_DPs || sopt->DPs == 0 || sopt->def_DP >= sopt->DPs)
366                 return -EINVAL;
367
368         sch_tree_lock(sch);
369         table->DPs = sopt->DPs;
370         table->def = sopt->def_DP;
371         table->red_flags = sopt->flags;
372
373         /*
374          * Every entry point to GRED is synchronized with the above code
375          * and the DP is checked against DPs, i.e. shadowed VQs can no
376          * longer be found so we can unlock right here.
377          */
378         sch_tree_unlock(sch);
379
380         if (sopt->grio) {
381                 gred_enable_rio_mode(table);
382                 gred_disable_wred_mode(table);
383                 if (gred_wred_mode_check(sch))
384                         gred_enable_wred_mode(table);
385         } else {
386                 gred_disable_rio_mode(table);
387                 gred_disable_wred_mode(table);
388         }
389
390         for (i = table->DPs; i < MAX_DPs; i++) {
391                 if (table->tab[i]) {
392                         printk(KERN_WARNING "GRED: Warning: Destroying "
393                                "shadowed VQ 0x%x\n", i);
394                         gred_destroy_vq(table->tab[i]);
395                         table->tab[i] = NULL;
396                 }
397         }
398
399         return 0;
400 }
401
402 static inline int gred_change_vq(struct Qdisc *sch, int dp,
403                                  struct tc_gred_qopt *ctl, int prio, u8 *stab)
404 {
405         struct gred_sched *table = qdisc_priv(sch);
406         struct gred_sched_data *q;
407
408         if (table->tab[dp] == NULL) {
409                 table->tab[dp] = kmalloc(sizeof(*q), GFP_KERNEL);
410                 if (table->tab[dp] == NULL)
411                         return -ENOMEM;
412                 memset(table->tab[dp], 0, sizeof(*q));
413         }
414
415         q = table->tab[dp];
416         q->DP = dp;
417         q->prio = prio;
418         q->limit = ctl->limit;
419
420         if (q->backlog == 0)
421                 red_end_of_idle_period(&q->parms);
422
423         red_set_parms(&q->parms,
424                       ctl->qth_min, ctl->qth_max, ctl->Wlog, ctl->Plog,
425                       ctl->Scell_log, stab);
426
427         return 0;
428 }
429
430 static int gred_change(struct Qdisc *sch, struct rtattr *opt)
431 {
432         struct gred_sched *table = qdisc_priv(sch);
433         struct tc_gred_qopt *ctl;
434         struct rtattr *tb[TCA_GRED_MAX];
435         int err = -EINVAL, prio = GRED_DEF_PRIO;
436         u8 *stab;
437
438         if (opt == NULL || rtattr_parse_nested(tb, TCA_GRED_MAX, opt))
439                 return -EINVAL;
440
441         if (tb[TCA_GRED_PARMS-1] == NULL && tb[TCA_GRED_STAB-1] == NULL)
442                 return gred_change_table_def(sch, opt);
443
444         if (tb[TCA_GRED_PARMS-1] == NULL ||
445             RTA_PAYLOAD(tb[TCA_GRED_PARMS-1]) < sizeof(*ctl) ||
446             tb[TCA_GRED_STAB-1] == NULL ||
447             RTA_PAYLOAD(tb[TCA_GRED_STAB-1]) < 256)
448                 return -EINVAL;
449
450         ctl = RTA_DATA(tb[TCA_GRED_PARMS-1]);
451         stab = RTA_DATA(tb[TCA_GRED_STAB-1]);
452
453         if (ctl->DP >= table->DPs)
454                 goto errout;
455
456         if (gred_rio_mode(table)) {
457                 if (ctl->prio == 0) {
458                         int def_prio = GRED_DEF_PRIO;
459
460                         if (table->tab[table->def])
461                                 def_prio = table->tab[table->def]->prio;
462
463                         printk(KERN_DEBUG "GRED: DP %u does not have a prio "
464                                "setting default to %d\n", ctl->DP, def_prio);
465
466                         prio = def_prio;
467                 } else
468                         prio = ctl->prio;
469         }
470
471         sch_tree_lock(sch);
472
473         err = gred_change_vq(sch, ctl->DP, ctl, prio, stab);
474         if (err < 0)
475                 goto errout_locked;
476
477         if (gred_rio_mode(table)) {
478                 gred_disable_wred_mode(table);
479                 if (gred_wred_mode_check(sch))
480                         gred_enable_wred_mode(table);
481         }
482
483         err = 0;
484
485 errout_locked:
486         sch_tree_unlock(sch);
487 errout:
488         return err;
489 }
490
491 static int gred_init(struct Qdisc *sch, struct rtattr *opt)
492 {
493         struct rtattr *tb[TCA_GRED_MAX];
494
495         if (opt == NULL || rtattr_parse_nested(tb, TCA_GRED_MAX, opt))
496                 return -EINVAL;
497
498         if (tb[TCA_GRED_PARMS-1] || tb[TCA_GRED_STAB-1])
499                 return -EINVAL;
500
501         return gred_change_table_def(sch, tb[TCA_GRED_DPS-1]);
502 }
503
504 static int gred_dump(struct Qdisc *sch, struct sk_buff *skb)
505 {
506         struct gred_sched *table = qdisc_priv(sch);
507         struct rtattr *parms, *opts = NULL;
508         int i;
509         struct tc_gred_sopt sopt = {
510                 .DPs    = table->DPs,
511                 .def_DP = table->def,
512                 .grio   = gred_rio_mode(table),
513                 .flags  = table->red_flags,
514         };
515
516         opts = RTA_NEST(skb, TCA_OPTIONS);
517         RTA_PUT(skb, TCA_GRED_DPS, sizeof(sopt), &sopt);
518         parms = RTA_NEST(skb, TCA_GRED_PARMS);
519
520         for (i = 0; i < MAX_DPs; i++) {
521                 struct gred_sched_data *q = table->tab[i];
522                 struct tc_gred_qopt opt;
523
524                 memset(&opt, 0, sizeof(opt));
525
526                 if (!q) {
527                         /* hack -- fix at some point with proper message
528                            This is how we indicate to tc that there is no VQ
529                            at this DP */
530
531                         opt.DP = MAX_DPs + i;
532                         goto append_opt;
533                 }
534
535                 opt.limit       = q->limit;
536                 opt.DP          = q->DP;
537                 opt.backlog     = q->backlog;
538                 opt.prio        = q->prio;
539                 opt.qth_min     = q->parms.qth_min >> q->parms.Wlog;
540                 opt.qth_max     = q->parms.qth_max >> q->parms.Wlog;
541                 opt.Wlog        = q->parms.Wlog;
542                 opt.Plog        = q->parms.Plog;
543                 opt.Scell_log   = q->parms.Scell_log;
544                 opt.other       = q->stats.other;
545                 opt.early       = q->stats.prob_drop;
546                 opt.forced      = q->stats.forced_drop;
547                 opt.pdrop       = q->stats.pdrop;
548                 opt.packets     = q->packetsin;
549                 opt.bytesin     = q->bytesin;
550
551                 if (gred_wred_mode(table)) {
552                         q->parms.qidlestart =
553                                 table->tab[table->def]->parms.qidlestart;
554                         q->parms.qavg = table->tab[table->def]->parms.qavg;
555                 }
556
557                 opt.qave = red_calc_qavg(&q->parms, q->parms.qavg);
558
559 append_opt:
560                 RTA_APPEND(skb, sizeof(opt), &opt);
561         }
562
563         RTA_NEST_END(skb, parms);
564
565         return RTA_NEST_END(skb, opts);
566
567 rtattr_failure:
568         return RTA_NEST_CANCEL(skb, opts);
569 }
570
571 static void gred_destroy(struct Qdisc *sch)
572 {
573         struct gred_sched *table = qdisc_priv(sch);
574         int i;
575
576         for (i = 0; i < table->DPs; i++) {
577                 if (table->tab[i])
578                         gred_destroy_vq(table->tab[i]);
579         }
580 }
581
582 static struct Qdisc_ops gred_qdisc_ops = {
583         .id             =       "gred",
584         .priv_size      =       sizeof(struct gred_sched),
585         .enqueue        =       gred_enqueue,
586         .dequeue        =       gred_dequeue,
587         .requeue        =       gred_requeue,
588         .drop           =       gred_drop,
589         .init           =       gred_init,
590         .reset          =       gred_reset,
591         .destroy        =       gred_destroy,
592         .change         =       gred_change,
593         .dump           =       gred_dump,
594         .owner          =       THIS_MODULE,
595 };
596
597 static int __init gred_module_init(void)
598 {
599         return register_qdisc(&gred_qdisc_ops);
600 }
601
602 static void __exit gred_module_exit(void)
603 {
604         unregister_qdisc(&gred_qdisc_ops);
605 }
606
607 module_init(gred_module_init)
608 module_exit(gred_module_exit)
609
610 MODULE_LICENSE("GPL");