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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> | |
cdfb74d4 | 17 | #include <linux/vmalloc.h> |
45e14433 | 18 | #include <net/pkt_sched.h> |
19 | #include <net/inet_ecn.h> | |
20 | #include <net/red.h> | |
2bcc34bb | 21 | #include <net/flow_keys.h> |
45e14433 | 22 | |
23 | /* | |
24 | CHOKe stateless AQM for fair bandwidth allocation | |
25 | ================================================= | |
26 | ||
27 | CHOKe (CHOose and Keep for responsive flows, CHOose and Kill for | |
28 | unresponsive flows) is a variant of RED that penalizes misbehaving flows but | |
29 | maintains no flow state. The difference from RED is an additional step | |
30 | during the enqueuing process. If average queue size is over the | |
31 | low threshold (qmin), a packet is chosen at random from the queue. | |
32 | If both the new and chosen packet are from the same flow, both | |
33 | are dropped. Unlike RED, CHOKe is not really a "classful" qdisc because it | |
34 | needs to access packets in queue randomly. It has a minimal class | |
35 | interface to allow overriding the builtin flow classifier with | |
36 | filters. | |
37 | ||
38 | Source: | |
39 | R. Pan, B. Prabhakar, and K. Psounis, "CHOKe, A Stateless | |
40 | Active Queue Management Scheme for Approximating Fair Bandwidth Allocation", | |
41 | IEEE INFOCOM, 2000. | |
42 | ||
43 | A. Tang, J. Wang, S. Low, "Understanding CHOKe: Throughput and Spatial | |
44 | Characteristics", IEEE/ACM Transactions on Networking, 2004 | |
45 | ||
46 | */ | |
47 | ||
48 | /* Upper bound on size of sk_buff table (packets) */ | |
49 | #define CHOKE_MAX_QUEUE (128*1024 - 1) | |
50 | ||
51 | struct choke_sched_data { | |
52 | /* Parameters */ | |
53 | u32 limit; | |
54 | unsigned char flags; | |
55 | ||
56 | struct red_parms parms; | |
57 | ||
58 | /* Variables */ | |
eeca6688 | 59 | struct red_vars vars; |
45e14433 | 60 | struct tcf_proto *filter_list; |
61 | struct { | |
62 | u32 prob_drop; /* Early probability drops */ | |
63 | u32 prob_mark; /* Early probability marks */ | |
64 | u32 forced_drop; /* Forced drops, qavg > max_thresh */ | |
65 | u32 forced_mark; /* Forced marks, qavg > max_thresh */ | |
66 | u32 pdrop; /* Drops due to queue limits */ | |
67 | u32 other; /* Drops due to drop() calls */ | |
68 | u32 matched; /* Drops to flow match */ | |
69 | } stats; | |
70 | ||
71 | unsigned int head; | |
72 | unsigned int tail; | |
73 | ||
74 | unsigned int tab_mask; /* size - 1 */ | |
75 | ||
76 | struct sk_buff **tab; | |
77 | }; | |
78 | ||
45e14433 | 79 | /* number of elements in queue including holes */ |
80 | static unsigned int choke_len(const struct choke_sched_data *q) | |
81 | { | |
82 | return (q->tail - q->head) & q->tab_mask; | |
83 | } | |
84 | ||
85 | /* Is ECN parameter configured */ | |
86 | static int use_ecn(const struct choke_sched_data *q) | |
87 | { | |
88 | return q->flags & TC_RED_ECN; | |
89 | } | |
90 | ||
91 | /* Should packets over max just be dropped (versus marked) */ | |
92 | static int use_harddrop(const struct choke_sched_data *q) | |
93 | { | |
94 | return q->flags & TC_RED_HARDDROP; | |
95 | } | |
96 | ||
97 | /* Move head pointer forward to skip over holes */ | |
98 | static void choke_zap_head_holes(struct choke_sched_data *q) | |
99 | { | |
100 | do { | |
101 | q->head = (q->head + 1) & q->tab_mask; | |
102 | if (q->head == q->tail) | |
103 | break; | |
104 | } while (q->tab[q->head] == NULL); | |
105 | } | |
106 | ||
107 | /* Move tail pointer backwards to reuse holes */ | |
108 | static void choke_zap_tail_holes(struct choke_sched_data *q) | |
109 | { | |
110 | do { | |
111 | q->tail = (q->tail - 1) & q->tab_mask; | |
112 | if (q->head == q->tail) | |
113 | break; | |
114 | } while (q->tab[q->tail] == NULL); | |
115 | } | |
116 | ||
117 | /* Drop packet from queue array by creating a "hole" */ | |
118 | static void choke_drop_by_idx(struct Qdisc *sch, unsigned int idx) | |
119 | { | |
120 | struct choke_sched_data *q = qdisc_priv(sch); | |
121 | struct sk_buff *skb = q->tab[idx]; | |
122 | ||
123 | q->tab[idx] = NULL; | |
124 | ||
125 | if (idx == q->head) | |
126 | choke_zap_head_holes(q); | |
127 | if (idx == q->tail) | |
128 | choke_zap_tail_holes(q); | |
129 | ||
130 | sch->qstats.backlog -= qdisc_pkt_len(skb); | |
131 | qdisc_drop(skb, sch); | |
132 | qdisc_tree_decrease_qlen(sch, 1); | |
133 | --sch->q.qlen; | |
134 | } | |
135 | ||
26f70e12 | 136 | struct choke_skb_cb { |
2bcc34bb ED |
137 | u16 classid; |
138 | u8 keys_valid; | |
139 | struct flow_keys keys; | |
26f70e12 ED |
140 | }; |
141 | ||
142 | static inline struct choke_skb_cb *choke_skb_cb(const struct sk_buff *skb) | |
143 | { | |
16bda13d | 144 | qdisc_cb_private_validate(skb, sizeof(struct choke_skb_cb)); |
26f70e12 ED |
145 | return (struct choke_skb_cb *)qdisc_skb_cb(skb)->data; |
146 | } | |
147 | ||
45e14433 | 148 | static inline void choke_set_classid(struct sk_buff *skb, u16 classid) |
149 | { | |
26f70e12 | 150 | choke_skb_cb(skb)->classid = classid; |
45e14433 | 151 | } |
152 | ||
153 | static u16 choke_get_classid(const struct sk_buff *skb) | |
154 | { | |
26f70e12 | 155 | return choke_skb_cb(skb)->classid; |
45e14433 | 156 | } |
157 | ||
2bcc34bb ED |
158 | /* |
159 | * Compare flow of two packets | |
160 | * Returns true only if source and destination address and port match. | |
161 | * false for special cases | |
162 | */ | |
163 | static bool choke_match_flow(struct sk_buff *skb1, | |
164 | struct sk_buff *skb2) | |
165 | { | |
166 | if (skb1->protocol != skb2->protocol) | |
167 | return false; | |
168 | ||
169 | if (!choke_skb_cb(skb1)->keys_valid) { | |
170 | choke_skb_cb(skb1)->keys_valid = 1; | |
171 | skb_flow_dissect(skb1, &choke_skb_cb(skb1)->keys); | |
172 | } | |
173 | ||
174 | if (!choke_skb_cb(skb2)->keys_valid) { | |
175 | choke_skb_cb(skb2)->keys_valid = 1; | |
176 | skb_flow_dissect(skb2, &choke_skb_cb(skb2)->keys); | |
177 | } | |
178 | ||
179 | return !memcmp(&choke_skb_cb(skb1)->keys, | |
180 | &choke_skb_cb(skb2)->keys, | |
181 | sizeof(struct flow_keys)); | |
182 | } | |
183 | ||
45e14433 | 184 | /* |
185 | * Classify flow using either: | |
186 | * 1. pre-existing classification result in skb | |
187 | * 2. fast internal classification | |
188 | * 3. use TC filter based classification | |
189 | */ | |
190 | static bool choke_classify(struct sk_buff *skb, | |
191 | struct Qdisc *sch, int *qerr) | |
192 | ||
193 | { | |
194 | struct choke_sched_data *q = qdisc_priv(sch); | |
195 | struct tcf_result res; | |
196 | int result; | |
197 | ||
198 | result = tc_classify(skb, q->filter_list, &res); | |
199 | if (result >= 0) { | |
200 | #ifdef CONFIG_NET_CLS_ACT | |
201 | switch (result) { | |
202 | case TC_ACT_STOLEN: | |
203 | case TC_ACT_QUEUED: | |
204 | *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN; | |
205 | case TC_ACT_SHOT: | |
206 | return false; | |
207 | } | |
208 | #endif | |
209 | choke_set_classid(skb, TC_H_MIN(res.classid)); | |
210 | return true; | |
211 | } | |
212 | ||
213 | return false; | |
214 | } | |
215 | ||
216 | /* | |
217 | * Select a packet at random from queue | |
218 | * HACK: since queue can have holes from previous deletion; retry several | |
219 | * times to find a random skb but then just give up and return the head | |
220 | * Will return NULL if queue is empty (q->head == q->tail) | |
221 | */ | |
222 | static struct sk_buff *choke_peek_random(const struct choke_sched_data *q, | |
223 | unsigned int *pidx) | |
224 | { | |
225 | struct sk_buff *skb; | |
226 | int retrys = 3; | |
227 | ||
228 | do { | |
f337db64 | 229 | *pidx = (q->head + prandom_u32_max(choke_len(q))) & q->tab_mask; |
45e14433 | 230 | skb = q->tab[*pidx]; |
231 | if (skb) | |
232 | return skb; | |
233 | } while (--retrys > 0); | |
234 | ||
235 | return q->tab[*pidx = q->head]; | |
236 | } | |
237 | ||
238 | /* | |
239 | * Compare new packet with random packet in queue | |
240 | * returns true if matched and sets *pidx | |
241 | */ | |
242 | static bool choke_match_random(const struct choke_sched_data *q, | |
243 | struct sk_buff *nskb, | |
244 | unsigned int *pidx) | |
245 | { | |
246 | struct sk_buff *oskb; | |
247 | ||
248 | if (q->head == q->tail) | |
249 | return false; | |
250 | ||
251 | oskb = choke_peek_random(q, pidx); | |
252 | if (q->filter_list) | |
253 | return choke_get_classid(nskb) == choke_get_classid(oskb); | |
254 | ||
255 | return choke_match_flow(oskb, nskb); | |
256 | } | |
257 | ||
258 | static int choke_enqueue(struct sk_buff *skb, struct Qdisc *sch) | |
259 | { | |
260 | struct choke_sched_data *q = qdisc_priv(sch); | |
eeca6688 | 261 | const struct red_parms *p = &q->parms; |
45e14433 | 262 | int ret = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; |
263 | ||
264 | if (q->filter_list) { | |
265 | /* If using external classifiers, get result and record it. */ | |
266 | if (!choke_classify(skb, sch, &ret)) | |
267 | goto other_drop; /* Packet was eaten by filter */ | |
268 | } | |
269 | ||
2bcc34bb | 270 | choke_skb_cb(skb)->keys_valid = 0; |
45e14433 | 271 | /* Compute average queue usage (see RED) */ |
eeca6688 ED |
272 | q->vars.qavg = red_calc_qavg(p, &q->vars, sch->q.qlen); |
273 | if (red_is_idling(&q->vars)) | |
274 | red_end_of_idle_period(&q->vars); | |
45e14433 | 275 | |
276 | /* Is queue small? */ | |
eeca6688 ED |
277 | if (q->vars.qavg <= p->qth_min) |
278 | q->vars.qcount = -1; | |
45e14433 | 279 | else { |
280 | unsigned int idx; | |
281 | ||
282 | /* Draw a packet at random from queue and compare flow */ | |
283 | if (choke_match_random(q, skb, &idx)) { | |
284 | q->stats.matched++; | |
285 | choke_drop_by_idx(sch, idx); | |
286 | goto congestion_drop; | |
287 | } | |
288 | ||
289 | /* Queue is large, always mark/drop */ | |
eeca6688 ED |
290 | if (q->vars.qavg > p->qth_max) { |
291 | q->vars.qcount = -1; | |
45e14433 | 292 | |
293 | sch->qstats.overlimits++; | |
294 | if (use_harddrop(q) || !use_ecn(q) || | |
295 | !INET_ECN_set_ce(skb)) { | |
296 | q->stats.forced_drop++; | |
297 | goto congestion_drop; | |
298 | } | |
299 | ||
300 | q->stats.forced_mark++; | |
eeca6688 ED |
301 | } else if (++q->vars.qcount) { |
302 | if (red_mark_probability(p, &q->vars, q->vars.qavg)) { | |
303 | q->vars.qcount = 0; | |
304 | q->vars.qR = red_random(p); | |
45e14433 | 305 | |
306 | sch->qstats.overlimits++; | |
307 | if (!use_ecn(q) || !INET_ECN_set_ce(skb)) { | |
308 | q->stats.prob_drop++; | |
309 | goto congestion_drop; | |
310 | } | |
311 | ||
312 | q->stats.prob_mark++; | |
313 | } | |
314 | } else | |
eeca6688 | 315 | q->vars.qR = red_random(p); |
45e14433 | 316 | } |
317 | ||
318 | /* Admit new packet */ | |
319 | if (sch->q.qlen < q->limit) { | |
320 | q->tab[q->tail] = skb; | |
321 | q->tail = (q->tail + 1) & q->tab_mask; | |
322 | ++sch->q.qlen; | |
323 | sch->qstats.backlog += qdisc_pkt_len(skb); | |
324 | return NET_XMIT_SUCCESS; | |
325 | } | |
326 | ||
327 | q->stats.pdrop++; | |
17045755 | 328 | return qdisc_drop(skb, sch); |
45e14433 | 329 | |
17045755 | 330 | congestion_drop: |
45e14433 | 331 | qdisc_drop(skb, sch); |
332 | return NET_XMIT_CN; | |
333 | ||
17045755 | 334 | other_drop: |
45e14433 | 335 | if (ret & __NET_XMIT_BYPASS) |
336 | sch->qstats.drops++; | |
337 | kfree_skb(skb); | |
338 | return ret; | |
339 | } | |
340 | ||
341 | static struct sk_buff *choke_dequeue(struct Qdisc *sch) | |
342 | { | |
343 | struct choke_sched_data *q = qdisc_priv(sch); | |
344 | struct sk_buff *skb; | |
345 | ||
346 | if (q->head == q->tail) { | |
eeca6688 ED |
347 | if (!red_is_idling(&q->vars)) |
348 | red_start_of_idle_period(&q->vars); | |
45e14433 | 349 | return NULL; |
350 | } | |
351 | ||
352 | skb = q->tab[q->head]; | |
353 | q->tab[q->head] = NULL; | |
354 | choke_zap_head_holes(q); | |
355 | --sch->q.qlen; | |
356 | sch->qstats.backlog -= qdisc_pkt_len(skb); | |
357 | qdisc_bstats_update(sch, skb); | |
358 | ||
359 | return skb; | |
360 | } | |
361 | ||
362 | static unsigned int choke_drop(struct Qdisc *sch) | |
363 | { | |
364 | struct choke_sched_data *q = qdisc_priv(sch); | |
365 | unsigned int len; | |
366 | ||
367 | len = qdisc_queue_drop(sch); | |
368 | if (len > 0) | |
369 | q->stats.other++; | |
370 | else { | |
eeca6688 ED |
371 | if (!red_is_idling(&q->vars)) |
372 | red_start_of_idle_period(&q->vars); | |
45e14433 | 373 | } |
374 | ||
375 | return len; | |
376 | } | |
377 | ||
378 | static void choke_reset(struct Qdisc *sch) | |
379 | { | |
380 | struct choke_sched_data *q = qdisc_priv(sch); | |
381 | ||
eeca6688 | 382 | red_restart(&q->vars); |
45e14433 | 383 | } |
384 | ||
385 | static const struct nla_policy choke_policy[TCA_CHOKE_MAX + 1] = { | |
386 | [TCA_CHOKE_PARMS] = { .len = sizeof(struct tc_red_qopt) }, | |
387 | [TCA_CHOKE_STAB] = { .len = RED_STAB_SIZE }, | |
a73ed26b | 388 | [TCA_CHOKE_MAX_P] = { .type = NLA_U32 }, |
45e14433 | 389 | }; |
390 | ||
391 | ||
392 | static void choke_free(void *addr) | |
393 | { | |
4cb28970 | 394 | kvfree(addr); |
45e14433 | 395 | } |
396 | ||
397 | static int choke_change(struct Qdisc *sch, struct nlattr *opt) | |
398 | { | |
399 | struct choke_sched_data *q = qdisc_priv(sch); | |
400 | struct nlattr *tb[TCA_CHOKE_MAX + 1]; | |
401 | const struct tc_red_qopt *ctl; | |
402 | int err; | |
403 | struct sk_buff **old = NULL; | |
404 | unsigned int mask; | |
a73ed26b | 405 | u32 max_P; |
45e14433 | 406 | |
407 | if (opt == NULL) | |
408 | return -EINVAL; | |
409 | ||
410 | err = nla_parse_nested(tb, TCA_CHOKE_MAX, opt, choke_policy); | |
411 | if (err < 0) | |
412 | return err; | |
413 | ||
414 | if (tb[TCA_CHOKE_PARMS] == NULL || | |
415 | tb[TCA_CHOKE_STAB] == NULL) | |
416 | return -EINVAL; | |
417 | ||
a73ed26b ED |
418 | max_P = tb[TCA_CHOKE_MAX_P] ? nla_get_u32(tb[TCA_CHOKE_MAX_P]) : 0; |
419 | ||
45e14433 | 420 | ctl = nla_data(tb[TCA_CHOKE_PARMS]); |
421 | ||
422 | if (ctl->limit > CHOKE_MAX_QUEUE) | |
423 | return -EINVAL; | |
424 | ||
425 | mask = roundup_pow_of_two(ctl->limit + 1) - 1; | |
426 | if (mask != q->tab_mask) { | |
427 | struct sk_buff **ntab; | |
428 | ||
8be04b93 JP |
429 | ntab = kcalloc(mask + 1, sizeof(struct sk_buff *), |
430 | GFP_KERNEL | __GFP_NOWARN); | |
45e14433 | 431 | if (!ntab) |
432 | ntab = vzalloc((mask + 1) * sizeof(struct sk_buff *)); | |
433 | if (!ntab) | |
434 | return -ENOMEM; | |
435 | ||
436 | sch_tree_lock(sch); | |
437 | old = q->tab; | |
438 | if (old) { | |
439 | unsigned int oqlen = sch->q.qlen, tail = 0; | |
440 | ||
441 | while (q->head != q->tail) { | |
442 | struct sk_buff *skb = q->tab[q->head]; | |
443 | ||
444 | q->head = (q->head + 1) & q->tab_mask; | |
445 | if (!skb) | |
446 | continue; | |
447 | if (tail < mask) { | |
448 | ntab[tail++] = skb; | |
449 | continue; | |
450 | } | |
451 | sch->qstats.backlog -= qdisc_pkt_len(skb); | |
452 | --sch->q.qlen; | |
453 | qdisc_drop(skb, sch); | |
454 | } | |
455 | qdisc_tree_decrease_qlen(sch, oqlen - sch->q.qlen); | |
456 | q->head = 0; | |
457 | q->tail = tail; | |
458 | } | |
459 | ||
460 | q->tab_mask = mask; | |
461 | q->tab = ntab; | |
462 | } else | |
463 | sch_tree_lock(sch); | |
464 | ||
465 | q->flags = ctl->flags; | |
466 | q->limit = ctl->limit; | |
467 | ||
468 | red_set_parms(&q->parms, ctl->qth_min, ctl->qth_max, ctl->Wlog, | |
469 | ctl->Plog, ctl->Scell_log, | |
a73ed26b ED |
470 | nla_data(tb[TCA_CHOKE_STAB]), |
471 | max_P); | |
eeca6688 | 472 | red_set_vars(&q->vars); |
45e14433 | 473 | |
474 | if (q->head == q->tail) | |
eeca6688 | 475 | red_end_of_idle_period(&q->vars); |
45e14433 | 476 | |
477 | sch_tree_unlock(sch); | |
478 | choke_free(old); | |
479 | return 0; | |
480 | } | |
481 | ||
482 | static int choke_init(struct Qdisc *sch, struct nlattr *opt) | |
483 | { | |
484 | return choke_change(sch, opt); | |
485 | } | |
486 | ||
487 | static int choke_dump(struct Qdisc *sch, struct sk_buff *skb) | |
488 | { | |
489 | struct choke_sched_data *q = qdisc_priv(sch); | |
490 | struct nlattr *opts = NULL; | |
491 | struct tc_red_qopt opt = { | |
492 | .limit = q->limit, | |
493 | .flags = q->flags, | |
494 | .qth_min = q->parms.qth_min >> q->parms.Wlog, | |
495 | .qth_max = q->parms.qth_max >> q->parms.Wlog, | |
496 | .Wlog = q->parms.Wlog, | |
497 | .Plog = q->parms.Plog, | |
498 | .Scell_log = q->parms.Scell_log, | |
499 | }; | |
500 | ||
501 | opts = nla_nest_start(skb, TCA_OPTIONS); | |
502 | if (opts == NULL) | |
503 | goto nla_put_failure; | |
504 | ||
1b34ec43 DM |
505 | if (nla_put(skb, TCA_CHOKE_PARMS, sizeof(opt), &opt) || |
506 | nla_put_u32(skb, TCA_CHOKE_MAX_P, q->parms.max_P)) | |
507 | goto nla_put_failure; | |
45e14433 | 508 | return nla_nest_end(skb, opts); |
509 | ||
510 | nla_put_failure: | |
511 | nla_nest_cancel(skb, opts); | |
512 | return -EMSGSIZE; | |
513 | } | |
514 | ||
515 | static int choke_dump_stats(struct Qdisc *sch, struct gnet_dump *d) | |
516 | { | |
517 | struct choke_sched_data *q = qdisc_priv(sch); | |
518 | struct tc_choke_xstats st = { | |
519 | .early = q->stats.prob_drop + q->stats.forced_drop, | |
520 | .marked = q->stats.prob_mark + q->stats.forced_mark, | |
521 | .pdrop = q->stats.pdrop, | |
522 | .other = q->stats.other, | |
523 | .matched = q->stats.matched, | |
524 | }; | |
525 | ||
526 | return gnet_stats_copy_app(d, &st, sizeof(st)); | |
527 | } | |
528 | ||
529 | static void choke_destroy(struct Qdisc *sch) | |
530 | { | |
531 | struct choke_sched_data *q = qdisc_priv(sch); | |
532 | ||
533 | tcf_destroy_chain(&q->filter_list); | |
534 | choke_free(q->tab); | |
535 | } | |
536 | ||
537 | static struct Qdisc *choke_leaf(struct Qdisc *sch, unsigned long arg) | |
538 | { | |
539 | return NULL; | |
540 | } | |
541 | ||
542 | static unsigned long choke_get(struct Qdisc *sch, u32 classid) | |
543 | { | |
544 | return 0; | |
545 | } | |
546 | ||
547 | static void choke_put(struct Qdisc *q, unsigned long cl) | |
548 | { | |
549 | } | |
550 | ||
551 | static unsigned long choke_bind(struct Qdisc *sch, unsigned long parent, | |
552 | u32 classid) | |
553 | { | |
554 | return 0; | |
555 | } | |
556 | ||
557 | static struct tcf_proto **choke_find_tcf(struct Qdisc *sch, unsigned long cl) | |
558 | { | |
559 | struct choke_sched_data *q = qdisc_priv(sch); | |
560 | ||
561 | if (cl) | |
562 | return NULL; | |
563 | return &q->filter_list; | |
564 | } | |
565 | ||
566 | static int choke_dump_class(struct Qdisc *sch, unsigned long cl, | |
567 | struct sk_buff *skb, struct tcmsg *tcm) | |
568 | { | |
569 | tcm->tcm_handle |= TC_H_MIN(cl); | |
570 | return 0; | |
571 | } | |
572 | ||
573 | static void choke_walk(struct Qdisc *sch, struct qdisc_walker *arg) | |
574 | { | |
575 | if (!arg->stop) { | |
576 | if (arg->fn(sch, 1, arg) < 0) { | |
577 | arg->stop = 1; | |
578 | return; | |
579 | } | |
580 | arg->count++; | |
581 | } | |
582 | } | |
583 | ||
584 | static const struct Qdisc_class_ops choke_class_ops = { | |
585 | .leaf = choke_leaf, | |
586 | .get = choke_get, | |
587 | .put = choke_put, | |
588 | .tcf_chain = choke_find_tcf, | |
589 | .bind_tcf = choke_bind, | |
590 | .unbind_tcf = choke_put, | |
591 | .dump = choke_dump_class, | |
592 | .walk = choke_walk, | |
593 | }; | |
594 | ||
595 | static struct sk_buff *choke_peek_head(struct Qdisc *sch) | |
596 | { | |
597 | struct choke_sched_data *q = qdisc_priv(sch); | |
598 | ||
599 | return (q->head != q->tail) ? q->tab[q->head] : NULL; | |
600 | } | |
601 | ||
602 | static struct Qdisc_ops choke_qdisc_ops __read_mostly = { | |
603 | .id = "choke", | |
604 | .priv_size = sizeof(struct choke_sched_data), | |
605 | ||
606 | .enqueue = choke_enqueue, | |
607 | .dequeue = choke_dequeue, | |
608 | .peek = choke_peek_head, | |
609 | .drop = choke_drop, | |
610 | .init = choke_init, | |
611 | .destroy = choke_destroy, | |
612 | .reset = choke_reset, | |
613 | .change = choke_change, | |
614 | .dump = choke_dump, | |
615 | .dump_stats = choke_dump_stats, | |
616 | .owner = THIS_MODULE, | |
617 | }; | |
618 | ||
619 | static int __init choke_module_init(void) | |
620 | { | |
621 | return register_qdisc(&choke_qdisc_ops); | |
622 | } | |
623 | ||
624 | static void __exit choke_module_exit(void) | |
625 | { | |
626 | unregister_qdisc(&choke_qdisc_ops); | |
627 | } | |
628 | ||
629 | module_init(choke_module_init) | |
630 | module_exit(choke_module_exit) | |
631 | ||
632 | MODULE_LICENSE("GPL"); |