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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> | |
1bd758eb | 21 | #include <net/flow_dissector.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; |
25d8c0d5 | 60 | struct tcf_proto __rcu *filter_list; |
45e14433 | 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" */ | |
520ac30f ED |
118 | static void choke_drop_by_idx(struct Qdisc *sch, unsigned int idx, |
119 | struct sk_buff **to_free) | |
45e14433 | 120 | { |
121 | struct choke_sched_data *q = qdisc_priv(sch); | |
122 | struct sk_buff *skb = q->tab[idx]; | |
123 | ||
124 | q->tab[idx] = NULL; | |
125 | ||
126 | if (idx == q->head) | |
127 | choke_zap_head_holes(q); | |
128 | if (idx == q->tail) | |
129 | choke_zap_tail_holes(q); | |
130 | ||
25331d6c | 131 | qdisc_qstats_backlog_dec(sch, skb); |
2ccccf5f | 132 | qdisc_tree_reduce_backlog(sch, 1, qdisc_pkt_len(skb)); |
520ac30f | 133 | qdisc_drop(skb, sch, to_free); |
45e14433 | 134 | --sch->q.qlen; |
135 | } | |
136 | ||
26f70e12 | 137 | struct choke_skb_cb { |
2bcc34bb ED |
138 | u16 classid; |
139 | u8 keys_valid; | |
2e99403d | 140 | struct flow_keys_digest keys; |
26f70e12 ED |
141 | }; |
142 | ||
143 | static inline struct choke_skb_cb *choke_skb_cb(const struct sk_buff *skb) | |
144 | { | |
16bda13d | 145 | qdisc_cb_private_validate(skb, sizeof(struct choke_skb_cb)); |
26f70e12 ED |
146 | return (struct choke_skb_cb *)qdisc_skb_cb(skb)->data; |
147 | } | |
148 | ||
45e14433 | 149 | static inline void choke_set_classid(struct sk_buff *skb, u16 classid) |
150 | { | |
26f70e12 | 151 | choke_skb_cb(skb)->classid = classid; |
45e14433 | 152 | } |
153 | ||
154 | static u16 choke_get_classid(const struct sk_buff *skb) | |
155 | { | |
26f70e12 | 156 | return choke_skb_cb(skb)->classid; |
45e14433 | 157 | } |
158 | ||
2bcc34bb ED |
159 | /* |
160 | * Compare flow of two packets | |
161 | * Returns true only if source and destination address and port match. | |
162 | * false for special cases | |
163 | */ | |
164 | static bool choke_match_flow(struct sk_buff *skb1, | |
165 | struct sk_buff *skb2) | |
166 | { | |
25711786 ED |
167 | struct flow_keys temp; |
168 | ||
2bcc34bb ED |
169 | if (skb1->protocol != skb2->protocol) |
170 | return false; | |
171 | ||
172 | if (!choke_skb_cb(skb1)->keys_valid) { | |
173 | choke_skb_cb(skb1)->keys_valid = 1; | |
cd79a238 | 174 | skb_flow_dissect_flow_keys(skb1, &temp, 0); |
2e99403d | 175 | make_flow_keys_digest(&choke_skb_cb(skb1)->keys, &temp); |
2bcc34bb ED |
176 | } |
177 | ||
178 | if (!choke_skb_cb(skb2)->keys_valid) { | |
179 | choke_skb_cb(skb2)->keys_valid = 1; | |
cd79a238 | 180 | skb_flow_dissect_flow_keys(skb2, &temp, 0); |
2e99403d | 181 | make_flow_keys_digest(&choke_skb_cb(skb2)->keys, &temp); |
2bcc34bb ED |
182 | } |
183 | ||
184 | return !memcmp(&choke_skb_cb(skb1)->keys, | |
185 | &choke_skb_cb(skb2)->keys, | |
2e99403d | 186 | sizeof(choke_skb_cb(skb1)->keys)); |
2bcc34bb ED |
187 | } |
188 | ||
45e14433 | 189 | /* |
190 | * Classify flow using either: | |
191 | * 1. pre-existing classification result in skb | |
192 | * 2. fast internal classification | |
193 | * 3. use TC filter based classification | |
194 | */ | |
195 | static bool choke_classify(struct sk_buff *skb, | |
196 | struct Qdisc *sch, int *qerr) | |
197 | ||
198 | { | |
199 | struct choke_sched_data *q = qdisc_priv(sch); | |
200 | struct tcf_result res; | |
25d8c0d5 | 201 | struct tcf_proto *fl; |
45e14433 | 202 | int result; |
203 | ||
25d8c0d5 | 204 | fl = rcu_dereference_bh(q->filter_list); |
3b3ae880 | 205 | result = tc_classify(skb, fl, &res, false); |
45e14433 | 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 { | |
f337db64 | 236 | *pidx = (q->head + prandom_u32_max(choke_len(q))) & q->tab_mask; |
45e14433 | 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); | |
25d8c0d5 | 259 | if (rcu_access_pointer(q->filter_list)) |
45e14433 | 260 | return choke_get_classid(nskb) == choke_get_classid(oskb); |
261 | ||
262 | return choke_match_flow(oskb, nskb); | |
263 | } | |
264 | ||
520ac30f ED |
265 | static int choke_enqueue(struct sk_buff *skb, struct Qdisc *sch, |
266 | struct sk_buff **to_free) | |
45e14433 | 267 | { |
25d8c0d5 | 268 | int ret = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; |
45e14433 | 269 | struct choke_sched_data *q = qdisc_priv(sch); |
eeca6688 | 270 | const struct red_parms *p = &q->parms; |
45e14433 | 271 | |
25d8c0d5 | 272 | if (rcu_access_pointer(q->filter_list)) { |
45e14433 | 273 | /* If using external classifiers, get result and record it. */ |
274 | if (!choke_classify(skb, sch, &ret)) | |
275 | goto other_drop; /* Packet was eaten by filter */ | |
276 | } | |
277 | ||
2bcc34bb | 278 | choke_skb_cb(skb)->keys_valid = 0; |
45e14433 | 279 | /* Compute average queue usage (see RED) */ |
eeca6688 ED |
280 | q->vars.qavg = red_calc_qavg(p, &q->vars, sch->q.qlen); |
281 | if (red_is_idling(&q->vars)) | |
282 | red_end_of_idle_period(&q->vars); | |
45e14433 | 283 | |
284 | /* Is queue small? */ | |
eeca6688 ED |
285 | if (q->vars.qavg <= p->qth_min) |
286 | q->vars.qcount = -1; | |
45e14433 | 287 | else { |
288 | unsigned int idx; | |
289 | ||
290 | /* Draw a packet at random from queue and compare flow */ | |
291 | if (choke_match_random(q, skb, &idx)) { | |
292 | q->stats.matched++; | |
520ac30f | 293 | choke_drop_by_idx(sch, idx, to_free); |
45e14433 | 294 | goto congestion_drop; |
295 | } | |
296 | ||
297 | /* Queue is large, always mark/drop */ | |
eeca6688 ED |
298 | if (q->vars.qavg > p->qth_max) { |
299 | q->vars.qcount = -1; | |
45e14433 | 300 | |
25331d6c | 301 | qdisc_qstats_overlimit(sch); |
45e14433 | 302 | if (use_harddrop(q) || !use_ecn(q) || |
303 | !INET_ECN_set_ce(skb)) { | |
304 | q->stats.forced_drop++; | |
305 | goto congestion_drop; | |
306 | } | |
307 | ||
308 | q->stats.forced_mark++; | |
eeca6688 ED |
309 | } else if (++q->vars.qcount) { |
310 | if (red_mark_probability(p, &q->vars, q->vars.qavg)) { | |
311 | q->vars.qcount = 0; | |
312 | q->vars.qR = red_random(p); | |
45e14433 | 313 | |
25331d6c | 314 | qdisc_qstats_overlimit(sch); |
45e14433 | 315 | if (!use_ecn(q) || !INET_ECN_set_ce(skb)) { |
316 | q->stats.prob_drop++; | |
317 | goto congestion_drop; | |
318 | } | |
319 | ||
320 | q->stats.prob_mark++; | |
321 | } | |
322 | } else | |
eeca6688 | 323 | q->vars.qR = red_random(p); |
45e14433 | 324 | } |
325 | ||
326 | /* Admit new packet */ | |
327 | if (sch->q.qlen < q->limit) { | |
328 | q->tab[q->tail] = skb; | |
329 | q->tail = (q->tail + 1) & q->tab_mask; | |
330 | ++sch->q.qlen; | |
25331d6c | 331 | qdisc_qstats_backlog_inc(sch, skb); |
45e14433 | 332 | return NET_XMIT_SUCCESS; |
333 | } | |
334 | ||
335 | q->stats.pdrop++; | |
520ac30f | 336 | return qdisc_drop(skb, sch, to_free); |
45e14433 | 337 | |
17045755 | 338 | congestion_drop: |
520ac30f | 339 | qdisc_drop(skb, sch, to_free); |
45e14433 | 340 | return NET_XMIT_CN; |
341 | ||
17045755 | 342 | other_drop: |
45e14433 | 343 | if (ret & __NET_XMIT_BYPASS) |
25331d6c | 344 | qdisc_qstats_drop(sch); |
520ac30f | 345 | __qdisc_drop(skb, to_free); |
45e14433 | 346 | return ret; |
347 | } | |
348 | ||
349 | static struct sk_buff *choke_dequeue(struct Qdisc *sch) | |
350 | { | |
351 | struct choke_sched_data *q = qdisc_priv(sch); | |
352 | struct sk_buff *skb; | |
353 | ||
354 | if (q->head == q->tail) { | |
eeca6688 ED |
355 | if (!red_is_idling(&q->vars)) |
356 | red_start_of_idle_period(&q->vars); | |
45e14433 | 357 | return NULL; |
358 | } | |
359 | ||
360 | skb = q->tab[q->head]; | |
361 | q->tab[q->head] = NULL; | |
362 | choke_zap_head_holes(q); | |
363 | --sch->q.qlen; | |
25331d6c | 364 | qdisc_qstats_backlog_dec(sch, skb); |
45e14433 | 365 | qdisc_bstats_update(sch, skb); |
366 | ||
367 | return skb; | |
368 | } | |
369 | ||
45e14433 | 370 | static void choke_reset(struct Qdisc *sch) |
371 | { | |
372 | struct choke_sched_data *q = qdisc_priv(sch); | |
373 | ||
77e62da6 WC |
374 | while (q->head != q->tail) { |
375 | struct sk_buff *skb = q->tab[q->head]; | |
376 | ||
377 | q->head = (q->head + 1) & q->tab_mask; | |
378 | if (!skb) | |
379 | continue; | |
f9aed311 | 380 | rtnl_qdisc_drop(skb, sch); |
77e62da6 WC |
381 | } |
382 | ||
f9aed311 ED |
383 | sch->q.qlen = 0; |
384 | sch->qstats.backlog = 0; | |
77e62da6 WC |
385 | memset(q->tab, 0, (q->tab_mask + 1) * sizeof(struct sk_buff *)); |
386 | q->head = q->tail = 0; | |
eeca6688 | 387 | red_restart(&q->vars); |
45e14433 | 388 | } |
389 | ||
390 | static const struct nla_policy choke_policy[TCA_CHOKE_MAX + 1] = { | |
391 | [TCA_CHOKE_PARMS] = { .len = sizeof(struct tc_red_qopt) }, | |
392 | [TCA_CHOKE_STAB] = { .len = RED_STAB_SIZE }, | |
a73ed26b | 393 | [TCA_CHOKE_MAX_P] = { .type = NLA_U32 }, |
45e14433 | 394 | }; |
395 | ||
396 | ||
397 | static void choke_free(void *addr) | |
398 | { | |
4cb28970 | 399 | kvfree(addr); |
45e14433 | 400 | } |
401 | ||
402 | static int choke_change(struct Qdisc *sch, struct nlattr *opt) | |
403 | { | |
404 | struct choke_sched_data *q = qdisc_priv(sch); | |
405 | struct nlattr *tb[TCA_CHOKE_MAX + 1]; | |
406 | const struct tc_red_qopt *ctl; | |
407 | int err; | |
408 | struct sk_buff **old = NULL; | |
409 | unsigned int mask; | |
a73ed26b | 410 | u32 max_P; |
45e14433 | 411 | |
412 | if (opt == NULL) | |
413 | return -EINVAL; | |
414 | ||
415 | err = nla_parse_nested(tb, TCA_CHOKE_MAX, opt, choke_policy); | |
416 | if (err < 0) | |
417 | return err; | |
418 | ||
419 | if (tb[TCA_CHOKE_PARMS] == NULL || | |
420 | tb[TCA_CHOKE_STAB] == NULL) | |
421 | return -EINVAL; | |
422 | ||
a73ed26b ED |
423 | max_P = tb[TCA_CHOKE_MAX_P] ? nla_get_u32(tb[TCA_CHOKE_MAX_P]) : 0; |
424 | ||
45e14433 | 425 | ctl = nla_data(tb[TCA_CHOKE_PARMS]); |
426 | ||
427 | if (ctl->limit > CHOKE_MAX_QUEUE) | |
428 | return -EINVAL; | |
429 | ||
430 | mask = roundup_pow_of_two(ctl->limit + 1) - 1; | |
431 | if (mask != q->tab_mask) { | |
432 | struct sk_buff **ntab; | |
433 | ||
8be04b93 JP |
434 | ntab = kcalloc(mask + 1, sizeof(struct sk_buff *), |
435 | GFP_KERNEL | __GFP_NOWARN); | |
45e14433 | 436 | if (!ntab) |
437 | ntab = vzalloc((mask + 1) * sizeof(struct sk_buff *)); | |
438 | if (!ntab) | |
439 | return -ENOMEM; | |
440 | ||
441 | sch_tree_lock(sch); | |
442 | old = q->tab; | |
443 | if (old) { | |
444 | unsigned int oqlen = sch->q.qlen, tail = 0; | |
2ccccf5f | 445 | unsigned dropped = 0; |
45e14433 | 446 | |
447 | while (q->head != q->tail) { | |
448 | struct sk_buff *skb = q->tab[q->head]; | |
449 | ||
450 | q->head = (q->head + 1) & q->tab_mask; | |
451 | if (!skb) | |
452 | continue; | |
453 | if (tail < mask) { | |
454 | ntab[tail++] = skb; | |
455 | continue; | |
456 | } | |
2ccccf5f | 457 | dropped += qdisc_pkt_len(skb); |
25331d6c | 458 | qdisc_qstats_backlog_dec(sch, skb); |
45e14433 | 459 | --sch->q.qlen; |
f9aed311 | 460 | rtnl_qdisc_drop(skb, sch); |
45e14433 | 461 | } |
2ccccf5f | 462 | qdisc_tree_reduce_backlog(sch, oqlen - sch->q.qlen, dropped); |
45e14433 | 463 | q->head = 0; |
464 | q->tail = tail; | |
465 | } | |
466 | ||
467 | q->tab_mask = mask; | |
468 | q->tab = ntab; | |
469 | } else | |
470 | sch_tree_lock(sch); | |
471 | ||
472 | q->flags = ctl->flags; | |
473 | q->limit = ctl->limit; | |
474 | ||
475 | red_set_parms(&q->parms, ctl->qth_min, ctl->qth_max, ctl->Wlog, | |
476 | ctl->Plog, ctl->Scell_log, | |
a73ed26b ED |
477 | nla_data(tb[TCA_CHOKE_STAB]), |
478 | max_P); | |
eeca6688 | 479 | red_set_vars(&q->vars); |
45e14433 | 480 | |
481 | if (q->head == q->tail) | |
eeca6688 | 482 | red_end_of_idle_period(&q->vars); |
45e14433 | 483 | |
484 | sch_tree_unlock(sch); | |
485 | choke_free(old); | |
486 | return 0; | |
487 | } | |
488 | ||
489 | static int choke_init(struct Qdisc *sch, struct nlattr *opt) | |
490 | { | |
491 | return choke_change(sch, opt); | |
492 | } | |
493 | ||
494 | static int choke_dump(struct Qdisc *sch, struct sk_buff *skb) | |
495 | { | |
496 | struct choke_sched_data *q = qdisc_priv(sch); | |
497 | struct nlattr *opts = NULL; | |
498 | struct tc_red_qopt opt = { | |
499 | .limit = q->limit, | |
500 | .flags = q->flags, | |
501 | .qth_min = q->parms.qth_min >> q->parms.Wlog, | |
502 | .qth_max = q->parms.qth_max >> q->parms.Wlog, | |
503 | .Wlog = q->parms.Wlog, | |
504 | .Plog = q->parms.Plog, | |
505 | .Scell_log = q->parms.Scell_log, | |
506 | }; | |
507 | ||
508 | opts = nla_nest_start(skb, TCA_OPTIONS); | |
509 | if (opts == NULL) | |
510 | goto nla_put_failure; | |
511 | ||
1b34ec43 DM |
512 | if (nla_put(skb, TCA_CHOKE_PARMS, sizeof(opt), &opt) || |
513 | nla_put_u32(skb, TCA_CHOKE_MAX_P, q->parms.max_P)) | |
514 | goto nla_put_failure; | |
45e14433 | 515 | return nla_nest_end(skb, opts); |
516 | ||
517 | nla_put_failure: | |
518 | nla_nest_cancel(skb, opts); | |
519 | return -EMSGSIZE; | |
520 | } | |
521 | ||
522 | static int choke_dump_stats(struct Qdisc *sch, struct gnet_dump *d) | |
523 | { | |
524 | struct choke_sched_data *q = qdisc_priv(sch); | |
525 | struct tc_choke_xstats st = { | |
526 | .early = q->stats.prob_drop + q->stats.forced_drop, | |
527 | .marked = q->stats.prob_mark + q->stats.forced_mark, | |
528 | .pdrop = q->stats.pdrop, | |
529 | .other = q->stats.other, | |
530 | .matched = q->stats.matched, | |
531 | }; | |
532 | ||
533 | return gnet_stats_copy_app(d, &st, sizeof(st)); | |
534 | } | |
535 | ||
536 | static void choke_destroy(struct Qdisc *sch) | |
537 | { | |
538 | struct choke_sched_data *q = qdisc_priv(sch); | |
539 | ||
540 | tcf_destroy_chain(&q->filter_list); | |
541 | choke_free(q->tab); | |
542 | } | |
543 | ||
45e14433 | 544 | static struct sk_buff *choke_peek_head(struct Qdisc *sch) |
545 | { | |
546 | struct choke_sched_data *q = qdisc_priv(sch); | |
547 | ||
548 | return (q->head != q->tail) ? q->tab[q->head] : NULL; | |
549 | } | |
550 | ||
551 | static struct Qdisc_ops choke_qdisc_ops __read_mostly = { | |
552 | .id = "choke", | |
553 | .priv_size = sizeof(struct choke_sched_data), | |
554 | ||
555 | .enqueue = choke_enqueue, | |
556 | .dequeue = choke_dequeue, | |
557 | .peek = choke_peek_head, | |
45e14433 | 558 | .init = choke_init, |
559 | .destroy = choke_destroy, | |
560 | .reset = choke_reset, | |
561 | .change = choke_change, | |
562 | .dump = choke_dump, | |
563 | .dump_stats = choke_dump_stats, | |
564 | .owner = THIS_MODULE, | |
565 | }; | |
566 | ||
567 | static int __init choke_module_init(void) | |
568 | { | |
569 | return register_qdisc(&choke_qdisc_ops); | |
570 | } | |
571 | ||
572 | static void __exit choke_module_exit(void) | |
573 | { | |
574 | unregister_qdisc(&choke_qdisc_ops); | |
575 | } | |
576 | ||
577 | module_init(choke_module_init) | |
578 | module_exit(choke_module_exit) | |
579 | ||
580 | MODULE_LICENSE("GPL"); |