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45e14433 | 1 | /* |
2 | * net/sched/sch_choke.c CHOKE scheduler | |
3 | * | |
4 | * Copyright (c) 2011 Stephen Hemminger <shemminger@vyatta.com> | |
5 | * Copyright (c) 2011 Eric Dumazet <eric.dumazet@gmail.com> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or | |
8 | * modify it under the terms of the GNU General Public License | |
9 | * version 2 as published by the Free Software Foundation. | |
10 | * | |
11 | */ | |
12 | ||
13 | #include <linux/module.h> | |
14 | #include <linux/types.h> | |
15 | #include <linux/kernel.h> | |
16 | #include <linux/skbuff.h> | |
17 | #include <linux/reciprocal_div.h> | |
cdfb74d4 | 18 | #include <linux/vmalloc.h> |
45e14433 | 19 | #include <net/pkt_sched.h> |
20 | #include <net/inet_ecn.h> | |
21 | #include <net/red.h> | |
2bcc34bb | 22 | #include <net/flow_keys.h> |
45e14433 | 23 | |
24 | /* | |
25 | CHOKe stateless AQM for fair bandwidth allocation | |
26 | ================================================= | |
27 | ||
28 | CHOKe (CHOose and Keep for responsive flows, CHOose and Kill for | |
29 | unresponsive flows) is a variant of RED that penalizes misbehaving flows but | |
30 | maintains no flow state. The difference from RED is an additional step | |
31 | during the enqueuing process. If average queue size is over the | |
32 | low threshold (qmin), a packet is chosen at random from the queue. | |
33 | If both the new and chosen packet are from the same flow, both | |
34 | are dropped. Unlike RED, CHOKe is not really a "classful" qdisc because it | |
35 | needs to access packets in queue randomly. It has a minimal class | |
36 | interface to allow overriding the builtin flow classifier with | |
37 | filters. | |
38 | ||
39 | Source: | |
40 | R. Pan, B. Prabhakar, and K. Psounis, "CHOKe, A Stateless | |
41 | Active Queue Management Scheme for Approximating Fair Bandwidth Allocation", | |
42 | IEEE INFOCOM, 2000. | |
43 | ||
44 | A. Tang, J. Wang, S. Low, "Understanding CHOKe: Throughput and Spatial | |
45 | Characteristics", IEEE/ACM Transactions on Networking, 2004 | |
46 | ||
47 | */ | |
48 | ||
49 | /* Upper bound on size of sk_buff table (packets) */ | |
50 | #define CHOKE_MAX_QUEUE (128*1024 - 1) | |
51 | ||
52 | struct choke_sched_data { | |
53 | /* Parameters */ | |
54 | u32 limit; | |
55 | unsigned char flags; | |
56 | ||
57 | struct red_parms parms; | |
58 | ||
59 | /* Variables */ | |
eeca6688 | 60 | struct red_vars vars; |
45e14433 | 61 | struct tcf_proto *filter_list; |
62 | struct { | |
63 | u32 prob_drop; /* Early probability drops */ | |
64 | u32 prob_mark; /* Early probability marks */ | |
65 | u32 forced_drop; /* Forced drops, qavg > max_thresh */ | |
66 | u32 forced_mark; /* Forced marks, qavg > max_thresh */ | |
67 | u32 pdrop; /* Drops due to queue limits */ | |
68 | u32 other; /* Drops due to drop() calls */ | |
69 | u32 matched; /* Drops to flow match */ | |
70 | } stats; | |
71 | ||
72 | unsigned int head; | |
73 | unsigned int tail; | |
74 | ||
75 | unsigned int tab_mask; /* size - 1 */ | |
76 | ||
77 | struct sk_buff **tab; | |
78 | }; | |
79 | ||
80 | /* deliver a random number between 0 and N - 1 */ | |
81 | static u32 random_N(unsigned int N) | |
82 | { | |
83 | return reciprocal_divide(random32(), N); | |
84 | } | |
85 | ||
86 | /* number of elements in queue including holes */ | |
87 | static unsigned int choke_len(const struct choke_sched_data *q) | |
88 | { | |
89 | return (q->tail - q->head) & q->tab_mask; | |
90 | } | |
91 | ||
92 | /* Is ECN parameter configured */ | |
93 | static int use_ecn(const struct choke_sched_data *q) | |
94 | { | |
95 | return q->flags & TC_RED_ECN; | |
96 | } | |
97 | ||
98 | /* Should packets over max just be dropped (versus marked) */ | |
99 | static int use_harddrop(const struct choke_sched_data *q) | |
100 | { | |
101 | return q->flags & TC_RED_HARDDROP; | |
102 | } | |
103 | ||
104 | /* Move head pointer forward to skip over holes */ | |
105 | static void choke_zap_head_holes(struct choke_sched_data *q) | |
106 | { | |
107 | do { | |
108 | q->head = (q->head + 1) & q->tab_mask; | |
109 | if (q->head == q->tail) | |
110 | break; | |
111 | } while (q->tab[q->head] == NULL); | |
112 | } | |
113 | ||
114 | /* Move tail pointer backwards to reuse holes */ | |
115 | static void choke_zap_tail_holes(struct choke_sched_data *q) | |
116 | { | |
117 | do { | |
118 | q->tail = (q->tail - 1) & q->tab_mask; | |
119 | if (q->head == q->tail) | |
120 | break; | |
121 | } while (q->tab[q->tail] == NULL); | |
122 | } | |
123 | ||
124 | /* Drop packet from queue array by creating a "hole" */ | |
125 | static void choke_drop_by_idx(struct Qdisc *sch, unsigned int idx) | |
126 | { | |
127 | struct choke_sched_data *q = qdisc_priv(sch); | |
128 | struct sk_buff *skb = q->tab[idx]; | |
129 | ||
130 | q->tab[idx] = NULL; | |
131 | ||
132 | if (idx == q->head) | |
133 | choke_zap_head_holes(q); | |
134 | if (idx == q->tail) | |
135 | choke_zap_tail_holes(q); | |
136 | ||
137 | sch->qstats.backlog -= qdisc_pkt_len(skb); | |
138 | qdisc_drop(skb, sch); | |
139 | qdisc_tree_decrease_qlen(sch, 1); | |
140 | --sch->q.qlen; | |
141 | } | |
142 | ||
26f70e12 | 143 | struct choke_skb_cb { |
2bcc34bb ED |
144 | u16 classid; |
145 | u8 keys_valid; | |
146 | struct flow_keys keys; | |
26f70e12 ED |
147 | }; |
148 | ||
149 | static inline struct choke_skb_cb *choke_skb_cb(const struct sk_buff *skb) | |
150 | { | |
16bda13d | 151 | qdisc_cb_private_validate(skb, sizeof(struct choke_skb_cb)); |
26f70e12 ED |
152 | return (struct choke_skb_cb *)qdisc_skb_cb(skb)->data; |
153 | } | |
154 | ||
45e14433 | 155 | static inline void choke_set_classid(struct sk_buff *skb, u16 classid) |
156 | { | |
26f70e12 | 157 | choke_skb_cb(skb)->classid = classid; |
45e14433 | 158 | } |
159 | ||
160 | static u16 choke_get_classid(const struct sk_buff *skb) | |
161 | { | |
26f70e12 | 162 | return choke_skb_cb(skb)->classid; |
45e14433 | 163 | } |
164 | ||
2bcc34bb ED |
165 | /* |
166 | * Compare flow of two packets | |
167 | * Returns true only if source and destination address and port match. | |
168 | * false for special cases | |
169 | */ | |
170 | static bool choke_match_flow(struct sk_buff *skb1, | |
171 | struct sk_buff *skb2) | |
172 | { | |
173 | if (skb1->protocol != skb2->protocol) | |
174 | return false; | |
175 | ||
176 | if (!choke_skb_cb(skb1)->keys_valid) { | |
177 | choke_skb_cb(skb1)->keys_valid = 1; | |
178 | skb_flow_dissect(skb1, &choke_skb_cb(skb1)->keys); | |
179 | } | |
180 | ||
181 | if (!choke_skb_cb(skb2)->keys_valid) { | |
182 | choke_skb_cb(skb2)->keys_valid = 1; | |
183 | skb_flow_dissect(skb2, &choke_skb_cb(skb2)->keys); | |
184 | } | |
185 | ||
186 | return !memcmp(&choke_skb_cb(skb1)->keys, | |
187 | &choke_skb_cb(skb2)->keys, | |
188 | sizeof(struct flow_keys)); | |
189 | } | |
190 | ||
45e14433 | 191 | /* |
192 | * Classify flow using either: | |
193 | * 1. pre-existing classification result in skb | |
194 | * 2. fast internal classification | |
195 | * 3. use TC filter based classification | |
196 | */ | |
197 | static bool choke_classify(struct sk_buff *skb, | |
198 | struct Qdisc *sch, int *qerr) | |
199 | ||
200 | { | |
201 | struct choke_sched_data *q = qdisc_priv(sch); | |
202 | struct tcf_result res; | |
203 | int result; | |
204 | ||
205 | result = tc_classify(skb, q->filter_list, &res); | |
206 | if (result >= 0) { | |
207 | #ifdef CONFIG_NET_CLS_ACT | |
208 | switch (result) { | |
209 | case TC_ACT_STOLEN: | |
210 | case TC_ACT_QUEUED: | |
211 | *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN; | |
212 | case TC_ACT_SHOT: | |
213 | return false; | |
214 | } | |
215 | #endif | |
216 | choke_set_classid(skb, TC_H_MIN(res.classid)); | |
217 | return true; | |
218 | } | |
219 | ||
220 | return false; | |
221 | } | |
222 | ||
223 | /* | |
224 | * Select a packet at random from queue | |
225 | * HACK: since queue can have holes from previous deletion; retry several | |
226 | * times to find a random skb but then just give up and return the head | |
227 | * Will return NULL if queue is empty (q->head == q->tail) | |
228 | */ | |
229 | static struct sk_buff *choke_peek_random(const struct choke_sched_data *q, | |
230 | unsigned int *pidx) | |
231 | { | |
232 | struct sk_buff *skb; | |
233 | int retrys = 3; | |
234 | ||
235 | do { | |
236 | *pidx = (q->head + random_N(choke_len(q))) & q->tab_mask; | |
237 | skb = q->tab[*pidx]; | |
238 | if (skb) | |
239 | return skb; | |
240 | } while (--retrys > 0); | |
241 | ||
242 | return q->tab[*pidx = q->head]; | |
243 | } | |
244 | ||
245 | /* | |
246 | * Compare new packet with random packet in queue | |
247 | * returns true if matched and sets *pidx | |
248 | */ | |
249 | static bool choke_match_random(const struct choke_sched_data *q, | |
250 | struct sk_buff *nskb, | |
251 | unsigned int *pidx) | |
252 | { | |
253 | struct sk_buff *oskb; | |
254 | ||
255 | if (q->head == q->tail) | |
256 | return false; | |
257 | ||
258 | oskb = choke_peek_random(q, pidx); | |
259 | if (q->filter_list) | |
260 | return choke_get_classid(nskb) == choke_get_classid(oskb); | |
261 | ||
262 | return choke_match_flow(oskb, nskb); | |
263 | } | |
264 | ||
265 | static int choke_enqueue(struct sk_buff *skb, struct Qdisc *sch) | |
266 | { | |
267 | struct choke_sched_data *q = qdisc_priv(sch); | |
eeca6688 | 268 | const struct red_parms *p = &q->parms; |
45e14433 | 269 | int ret = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; |
270 | ||
271 | if (q->filter_list) { | |
272 | /* If using external classifiers, get result and record it. */ | |
273 | if (!choke_classify(skb, sch, &ret)) | |
274 | goto other_drop; /* Packet was eaten by filter */ | |
275 | } | |
276 | ||
2bcc34bb | 277 | choke_skb_cb(skb)->keys_valid = 0; |
45e14433 | 278 | /* Compute average queue usage (see RED) */ |
eeca6688 ED |
279 | q->vars.qavg = red_calc_qavg(p, &q->vars, sch->q.qlen); |
280 | if (red_is_idling(&q->vars)) | |
281 | red_end_of_idle_period(&q->vars); | |
45e14433 | 282 | |
283 | /* Is queue small? */ | |
eeca6688 ED |
284 | if (q->vars.qavg <= p->qth_min) |
285 | q->vars.qcount = -1; | |
45e14433 | 286 | else { |
287 | unsigned int idx; | |
288 | ||
289 | /* Draw a packet at random from queue and compare flow */ | |
290 | if (choke_match_random(q, skb, &idx)) { | |
291 | q->stats.matched++; | |
292 | choke_drop_by_idx(sch, idx); | |
293 | goto congestion_drop; | |
294 | } | |
295 | ||
296 | /* Queue is large, always mark/drop */ | |
eeca6688 ED |
297 | if (q->vars.qavg > p->qth_max) { |
298 | q->vars.qcount = -1; | |
45e14433 | 299 | |
300 | sch->qstats.overlimits++; | |
301 | if (use_harddrop(q) || !use_ecn(q) || | |
302 | !INET_ECN_set_ce(skb)) { | |
303 | q->stats.forced_drop++; | |
304 | goto congestion_drop; | |
305 | } | |
306 | ||
307 | q->stats.forced_mark++; | |
eeca6688 ED |
308 | } else if (++q->vars.qcount) { |
309 | if (red_mark_probability(p, &q->vars, q->vars.qavg)) { | |
310 | q->vars.qcount = 0; | |
311 | q->vars.qR = red_random(p); | |
45e14433 | 312 | |
313 | sch->qstats.overlimits++; | |
314 | if (!use_ecn(q) || !INET_ECN_set_ce(skb)) { | |
315 | q->stats.prob_drop++; | |
316 | goto congestion_drop; | |
317 | } | |
318 | ||
319 | q->stats.prob_mark++; | |
320 | } | |
321 | } else | |
eeca6688 | 322 | q->vars.qR = red_random(p); |
45e14433 | 323 | } |
324 | ||
325 | /* Admit new packet */ | |
326 | if (sch->q.qlen < q->limit) { | |
327 | q->tab[q->tail] = skb; | |
328 | q->tail = (q->tail + 1) & q->tab_mask; | |
329 | ++sch->q.qlen; | |
330 | sch->qstats.backlog += qdisc_pkt_len(skb); | |
331 | return NET_XMIT_SUCCESS; | |
332 | } | |
333 | ||
334 | q->stats.pdrop++; | |
17045755 | 335 | return qdisc_drop(skb, sch); |
45e14433 | 336 | |
17045755 | 337 | congestion_drop: |
45e14433 | 338 | qdisc_drop(skb, sch); |
339 | return NET_XMIT_CN; | |
340 | ||
17045755 | 341 | other_drop: |
45e14433 | 342 | if (ret & __NET_XMIT_BYPASS) |
343 | sch->qstats.drops++; | |
344 | kfree_skb(skb); | |
345 | return ret; | |
346 | } | |
347 | ||
348 | static struct sk_buff *choke_dequeue(struct Qdisc *sch) | |
349 | { | |
350 | struct choke_sched_data *q = qdisc_priv(sch); | |
351 | struct sk_buff *skb; | |
352 | ||
353 | if (q->head == q->tail) { | |
eeca6688 ED |
354 | if (!red_is_idling(&q->vars)) |
355 | red_start_of_idle_period(&q->vars); | |
45e14433 | 356 | return NULL; |
357 | } | |
358 | ||
359 | skb = q->tab[q->head]; | |
360 | q->tab[q->head] = NULL; | |
361 | choke_zap_head_holes(q); | |
362 | --sch->q.qlen; | |
363 | sch->qstats.backlog -= qdisc_pkt_len(skb); | |
364 | qdisc_bstats_update(sch, skb); | |
365 | ||
366 | return skb; | |
367 | } | |
368 | ||
369 | static unsigned int choke_drop(struct Qdisc *sch) | |
370 | { | |
371 | struct choke_sched_data *q = qdisc_priv(sch); | |
372 | unsigned int len; | |
373 | ||
374 | len = qdisc_queue_drop(sch); | |
375 | if (len > 0) | |
376 | q->stats.other++; | |
377 | else { | |
eeca6688 ED |
378 | if (!red_is_idling(&q->vars)) |
379 | red_start_of_idle_period(&q->vars); | |
45e14433 | 380 | } |
381 | ||
382 | return len; | |
383 | } | |
384 | ||
385 | static void choke_reset(struct Qdisc *sch) | |
386 | { | |
387 | struct choke_sched_data *q = qdisc_priv(sch); | |
388 | ||
eeca6688 | 389 | red_restart(&q->vars); |
45e14433 | 390 | } |
391 | ||
392 | static const struct nla_policy choke_policy[TCA_CHOKE_MAX + 1] = { | |
393 | [TCA_CHOKE_PARMS] = { .len = sizeof(struct tc_red_qopt) }, | |
394 | [TCA_CHOKE_STAB] = { .len = RED_STAB_SIZE }, | |
a73ed26b | 395 | [TCA_CHOKE_MAX_P] = { .type = NLA_U32 }, |
45e14433 | 396 | }; |
397 | ||
398 | ||
399 | static void choke_free(void *addr) | |
400 | { | |
401 | if (addr) { | |
402 | if (is_vmalloc_addr(addr)) | |
403 | vfree(addr); | |
404 | else | |
405 | kfree(addr); | |
406 | } | |
407 | } | |
408 | ||
409 | static int choke_change(struct Qdisc *sch, struct nlattr *opt) | |
410 | { | |
411 | struct choke_sched_data *q = qdisc_priv(sch); | |
412 | struct nlattr *tb[TCA_CHOKE_MAX + 1]; | |
413 | const struct tc_red_qopt *ctl; | |
414 | int err; | |
415 | struct sk_buff **old = NULL; | |
416 | unsigned int mask; | |
a73ed26b | 417 | u32 max_P; |
45e14433 | 418 | |
419 | if (opt == NULL) | |
420 | return -EINVAL; | |
421 | ||
422 | err = nla_parse_nested(tb, TCA_CHOKE_MAX, opt, choke_policy); | |
423 | if (err < 0) | |
424 | return err; | |
425 | ||
426 | if (tb[TCA_CHOKE_PARMS] == NULL || | |
427 | tb[TCA_CHOKE_STAB] == NULL) | |
428 | return -EINVAL; | |
429 | ||
a73ed26b ED |
430 | max_P = tb[TCA_CHOKE_MAX_P] ? nla_get_u32(tb[TCA_CHOKE_MAX_P]) : 0; |
431 | ||
45e14433 | 432 | ctl = nla_data(tb[TCA_CHOKE_PARMS]); |
433 | ||
434 | if (ctl->limit > CHOKE_MAX_QUEUE) | |
435 | return -EINVAL; | |
436 | ||
437 | mask = roundup_pow_of_two(ctl->limit + 1) - 1; | |
438 | if (mask != q->tab_mask) { | |
439 | struct sk_buff **ntab; | |
440 | ||
441 | ntab = kcalloc(mask + 1, sizeof(struct sk_buff *), GFP_KERNEL); | |
442 | if (!ntab) | |
443 | ntab = vzalloc((mask + 1) * sizeof(struct sk_buff *)); | |
444 | if (!ntab) | |
445 | return -ENOMEM; | |
446 | ||
447 | sch_tree_lock(sch); | |
448 | old = q->tab; | |
449 | if (old) { | |
450 | unsigned int oqlen = sch->q.qlen, tail = 0; | |
451 | ||
452 | while (q->head != q->tail) { | |
453 | struct sk_buff *skb = q->tab[q->head]; | |
454 | ||
455 | q->head = (q->head + 1) & q->tab_mask; | |
456 | if (!skb) | |
457 | continue; | |
458 | if (tail < mask) { | |
459 | ntab[tail++] = skb; | |
460 | continue; | |
461 | } | |
462 | sch->qstats.backlog -= qdisc_pkt_len(skb); | |
463 | --sch->q.qlen; | |
464 | qdisc_drop(skb, sch); | |
465 | } | |
466 | qdisc_tree_decrease_qlen(sch, oqlen - sch->q.qlen); | |
467 | q->head = 0; | |
468 | q->tail = tail; | |
469 | } | |
470 | ||
471 | q->tab_mask = mask; | |
472 | q->tab = ntab; | |
473 | } else | |
474 | sch_tree_lock(sch); | |
475 | ||
476 | q->flags = ctl->flags; | |
477 | q->limit = ctl->limit; | |
478 | ||
479 | red_set_parms(&q->parms, ctl->qth_min, ctl->qth_max, ctl->Wlog, | |
480 | ctl->Plog, ctl->Scell_log, | |
a73ed26b ED |
481 | nla_data(tb[TCA_CHOKE_STAB]), |
482 | max_P); | |
eeca6688 | 483 | red_set_vars(&q->vars); |
45e14433 | 484 | |
485 | if (q->head == q->tail) | |
eeca6688 | 486 | red_end_of_idle_period(&q->vars); |
45e14433 | 487 | |
488 | sch_tree_unlock(sch); | |
489 | choke_free(old); | |
490 | return 0; | |
491 | } | |
492 | ||
493 | static int choke_init(struct Qdisc *sch, struct nlattr *opt) | |
494 | { | |
495 | return choke_change(sch, opt); | |
496 | } | |
497 | ||
498 | static int choke_dump(struct Qdisc *sch, struct sk_buff *skb) | |
499 | { | |
500 | struct choke_sched_data *q = qdisc_priv(sch); | |
501 | struct nlattr *opts = NULL; | |
502 | struct tc_red_qopt opt = { | |
503 | .limit = q->limit, | |
504 | .flags = q->flags, | |
505 | .qth_min = q->parms.qth_min >> q->parms.Wlog, | |
506 | .qth_max = q->parms.qth_max >> q->parms.Wlog, | |
507 | .Wlog = q->parms.Wlog, | |
508 | .Plog = q->parms.Plog, | |
509 | .Scell_log = q->parms.Scell_log, | |
510 | }; | |
511 | ||
512 | opts = nla_nest_start(skb, TCA_OPTIONS); | |
513 | if (opts == NULL) | |
514 | goto nla_put_failure; | |
515 | ||
1b34ec43 DM |
516 | if (nla_put(skb, TCA_CHOKE_PARMS, sizeof(opt), &opt) || |
517 | nla_put_u32(skb, TCA_CHOKE_MAX_P, q->parms.max_P)) | |
518 | goto nla_put_failure; | |
45e14433 | 519 | return nla_nest_end(skb, opts); |
520 | ||
521 | nla_put_failure: | |
522 | nla_nest_cancel(skb, opts); | |
523 | return -EMSGSIZE; | |
524 | } | |
525 | ||
526 | static int choke_dump_stats(struct Qdisc *sch, struct gnet_dump *d) | |
527 | { | |
528 | struct choke_sched_data *q = qdisc_priv(sch); | |
529 | struct tc_choke_xstats st = { | |
530 | .early = q->stats.prob_drop + q->stats.forced_drop, | |
531 | .marked = q->stats.prob_mark + q->stats.forced_mark, | |
532 | .pdrop = q->stats.pdrop, | |
533 | .other = q->stats.other, | |
534 | .matched = q->stats.matched, | |
535 | }; | |
536 | ||
537 | return gnet_stats_copy_app(d, &st, sizeof(st)); | |
538 | } | |
539 | ||
540 | static void choke_destroy(struct Qdisc *sch) | |
541 | { | |
542 | struct choke_sched_data *q = qdisc_priv(sch); | |
543 | ||
544 | tcf_destroy_chain(&q->filter_list); | |
545 | choke_free(q->tab); | |
546 | } | |
547 | ||
548 | static struct Qdisc *choke_leaf(struct Qdisc *sch, unsigned long arg) | |
549 | { | |
550 | return NULL; | |
551 | } | |
552 | ||
553 | static unsigned long choke_get(struct Qdisc *sch, u32 classid) | |
554 | { | |
555 | return 0; | |
556 | } | |
557 | ||
558 | static void choke_put(struct Qdisc *q, unsigned long cl) | |
559 | { | |
560 | } | |
561 | ||
562 | static unsigned long choke_bind(struct Qdisc *sch, unsigned long parent, | |
563 | u32 classid) | |
564 | { | |
565 | return 0; | |
566 | } | |
567 | ||
568 | static struct tcf_proto **choke_find_tcf(struct Qdisc *sch, unsigned long cl) | |
569 | { | |
570 | struct choke_sched_data *q = qdisc_priv(sch); | |
571 | ||
572 | if (cl) | |
573 | return NULL; | |
574 | return &q->filter_list; | |
575 | } | |
576 | ||
577 | static int choke_dump_class(struct Qdisc *sch, unsigned long cl, | |
578 | struct sk_buff *skb, struct tcmsg *tcm) | |
579 | { | |
580 | tcm->tcm_handle |= TC_H_MIN(cl); | |
581 | return 0; | |
582 | } | |
583 | ||
584 | static void choke_walk(struct Qdisc *sch, struct qdisc_walker *arg) | |
585 | { | |
586 | if (!arg->stop) { | |
587 | if (arg->fn(sch, 1, arg) < 0) { | |
588 | arg->stop = 1; | |
589 | return; | |
590 | } | |
591 | arg->count++; | |
592 | } | |
593 | } | |
594 | ||
595 | static const struct Qdisc_class_ops choke_class_ops = { | |
596 | .leaf = choke_leaf, | |
597 | .get = choke_get, | |
598 | .put = choke_put, | |
599 | .tcf_chain = choke_find_tcf, | |
600 | .bind_tcf = choke_bind, | |
601 | .unbind_tcf = choke_put, | |
602 | .dump = choke_dump_class, | |
603 | .walk = choke_walk, | |
604 | }; | |
605 | ||
606 | static struct sk_buff *choke_peek_head(struct Qdisc *sch) | |
607 | { | |
608 | struct choke_sched_data *q = qdisc_priv(sch); | |
609 | ||
610 | return (q->head != q->tail) ? q->tab[q->head] : NULL; | |
611 | } | |
612 | ||
613 | static struct Qdisc_ops choke_qdisc_ops __read_mostly = { | |
614 | .id = "choke", | |
615 | .priv_size = sizeof(struct choke_sched_data), | |
616 | ||
617 | .enqueue = choke_enqueue, | |
618 | .dequeue = choke_dequeue, | |
619 | .peek = choke_peek_head, | |
620 | .drop = choke_drop, | |
621 | .init = choke_init, | |
622 | .destroy = choke_destroy, | |
623 | .reset = choke_reset, | |
624 | .change = choke_change, | |
625 | .dump = choke_dump, | |
626 | .dump_stats = choke_dump_stats, | |
627 | .owner = THIS_MODULE, | |
628 | }; | |
629 | ||
630 | static int __init choke_module_init(void) | |
631 | { | |
632 | return register_qdisc(&choke_qdisc_ops); | |
633 | } | |
634 | ||
635 | static void __exit choke_module_exit(void) | |
636 | { | |
637 | unregister_qdisc(&choke_qdisc_ops); | |
638 | } | |
639 | ||
640 | module_init(choke_module_init) | |
641 | module_exit(choke_module_exit) | |
642 | ||
643 | MODULE_LICENSE("GPL"); |