1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Fair Queue CoDel discipline
4 *
5 * Copyright (C) 2012,2015 Eric Dumazet <edumazet@google.com>
6 */
7
8 #include <linux/module.h>
9 #include <linux/types.h>
10 #include <linux/kernel.h>
11 #include <linux/jiffies.h>
12 #include <linux/string.h>
13 #include <linux/in.h>
14 #include <linux/errno.h>
15 #include <linux/init.h>
16 #include <linux/skbuff.h>
17 #include <linux/slab.h>
18 #include <linux/vmalloc.h>
19 #include <net/netlink.h>
20 #include <net/pkt_sched.h>
21 #include <net/pkt_cls.h>
22 #include <net/codel.h>
23 #include <net/codel_impl.h>
24 #include <net/codel_qdisc.h>
25
26 /* Fair Queue CoDel.
27 *
28 * Principles :
29 * Packets are classified (internal classifier or external) on flows.
30 * This is a Stochastic model (as we use a hash, several flows
31 * might be hashed on same slot)
32 * Each flow has a CoDel managed queue.
33 * Flows are linked onto two (Round Robin) lists,
34 * so that new flows have priority on old ones.
35 *
36 * For a given flow, packets are not reordered (CoDel uses a FIFO)
37 * head drops only.
38 * ECN capability is on by default.
39 * Low memory footprint (64 bytes per flow)
40 */
41
42 struct fq_codel_flow {
43 struct sk_buff *head;
44 struct sk_buff *tail;
45 struct list_head flowchain;
46 int deficit;
47 struct codel_vars cvars;
48 }; /* please try to keep this structure <= 64 bytes */
49
50 struct fq_codel_sched_data {
51 struct tcf_proto __rcu *filter_list; /* optional external classifier */
52 struct tcf_block *block;
53 struct fq_codel_flow *flows; /* Flows table [flows_cnt] */
54 u32 *backlogs; /* backlog table [flows_cnt] */
55 u32 flows_cnt; /* number of flows */
56 u32 quantum; /* psched_mtu(qdisc_dev(sch)); */
57 u32 drop_batch_size;
58 u32 memory_limit;
59 struct codel_params cparams;
60 struct codel_stats cstats;
61 u32 memory_usage;
62 u32 drop_overmemory;
63 u32 drop_overlimit;
64 u32 new_flow_count;
65
66 struct list_head new_flows; /* list of new flows */
67 struct list_head old_flows; /* list of old flows */
68 };
69
fq_codel_hash(const struct fq_codel_sched_data * q,struct sk_buff * skb)70 static unsigned int fq_codel_hash(const struct fq_codel_sched_data *q,
71 struct sk_buff *skb)
72 {
73 return reciprocal_scale(skb_get_hash(skb), q->flows_cnt);
74 }
75
fq_codel_classify(struct sk_buff * skb,struct Qdisc * sch,int * qerr)76 static unsigned int fq_codel_classify(struct sk_buff *skb, struct Qdisc *sch,
77 int *qerr)
78 {
79 struct fq_codel_sched_data *q = qdisc_priv(sch);
80 struct tcf_proto *filter;
81 struct tcf_result res;
82 int result;
83
84 if (TC_H_MAJ(skb->priority) == sch->handle &&
85 TC_H_MIN(skb->priority) > 0 &&
86 TC_H_MIN(skb->priority) <= q->flows_cnt)
87 return TC_H_MIN(skb->priority);
88
89 filter = rcu_dereference_bh(q->filter_list);
90 if (!filter)
91 return fq_codel_hash(q, skb) + 1;
92
93 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
94 result = tcf_classify_qdisc(skb, filter, &res, false);
95 if (result >= 0) {
96 #ifdef CONFIG_NET_CLS_ACT
97 switch (result) {
98 case TC_ACT_STOLEN:
99 case TC_ACT_QUEUED:
100 case TC_ACT_TRAP:
101 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
102 fallthrough;
103 case TC_ACT_SHOT:
104 return 0;
105 }
106 #endif
107 if (TC_H_MIN(res.classid) <= q->flows_cnt)
108 return TC_H_MIN(res.classid);
109 }
110 return 0;
111 }
112
113 /* helper functions : might be changed when/if skb use a standard list_head */
114
115 /* remove one skb from head of slot queue */
dequeue_head(struct fq_codel_flow * flow)116 static inline struct sk_buff *dequeue_head(struct fq_codel_flow *flow)
117 {
118 struct sk_buff *skb = flow->head;
119
120 WRITE_ONCE(flow->head, skb->next);
121 skb_mark_not_on_list(skb);
122 return skb;
123 }
124
125 /* add skb to flow queue (tail add) */
flow_queue_add(struct fq_codel_flow * flow,struct sk_buff * skb)126 static inline void flow_queue_add(struct fq_codel_flow *flow,
127 struct sk_buff *skb)
128 {
129 if (flow->head == NULL)
130 WRITE_ONCE(flow->head, skb);
131 else
132 flow->tail->next = skb;
133 flow->tail = skb;
134 skb->next = NULL;
135 }
136
fq_codel_drop(struct Qdisc * sch,unsigned int max_packets,struct sk_buff ** to_free)137 static unsigned int fq_codel_drop(struct Qdisc *sch, unsigned int max_packets,
138 struct sk_buff **to_free)
139 {
140 struct fq_codel_sched_data *q = qdisc_priv(sch);
141 struct sk_buff *skb;
142 unsigned int maxbacklog = 0, idx = 0, i, len;
143 struct fq_codel_flow *flow;
144 unsigned int threshold;
145 unsigned int mem = 0;
146
147 /* Queue is full! Find the fat flow and drop packet(s) from it.
148 * This might sound expensive, but with 1024 flows, we scan
149 * 4KB of memory, and we dont need to handle a complex tree
150 * in fast path (packet queue/enqueue) with many cache misses.
151 * In stress mode, we'll try to drop 64 packets from the flow,
152 * amortizing this linear lookup to one cache line per drop.
153 */
154 for (i = 0; i < q->flows_cnt; i++) {
155 if (q->backlogs[i] > maxbacklog) {
156 maxbacklog = q->backlogs[i];
157 idx = i;
158 }
159 }
160
161 /* Our goal is to drop half of this fat flow backlog */
162 threshold = maxbacklog >> 1;
163
164 flow = &q->flows[idx];
165 len = 0;
166 i = 0;
167 do {
168 skb = dequeue_head(flow);
169 len += qdisc_pkt_len(skb);
170 mem += get_codel_cb(skb)->mem_usage;
171 tcf_set_qdisc_drop_reason(skb, QDISC_DROP_OVERLIMIT);
172 __qdisc_drop(skb, to_free);
173 } while (++i < max_packets && len < threshold);
174
175 /* Tell codel to increase its signal strength also */
176 WRITE_ONCE(flow->cvars.count, flow->cvars.count + i);
177 WRITE_ONCE(q->backlogs[idx], q->backlogs[idx] - len);
178 q->memory_usage -= mem;
179 __qdisc_qstats_drop(sch, i);
180 qstats_backlog_sub(sch, len);
181 WRITE_ONCE(sch->q.qlen, sch->q.qlen - i);
182 return idx;
183 }
184
fq_codel_enqueue(struct sk_buff * skb,struct Qdisc * sch,struct sk_buff ** to_free)185 static int fq_codel_enqueue(struct sk_buff *skb, struct Qdisc *sch,
186 struct sk_buff **to_free)
187 {
188 struct fq_codel_sched_data *q = qdisc_priv(sch);
189 unsigned int idx, prev_backlog, prev_qlen;
190 struct fq_codel_flow *flow;
191 int ret;
192 unsigned int pkt_len;
193 bool memory_limited;
194
195 idx = fq_codel_classify(skb, sch, &ret);
196 if (idx == 0) {
197 if (ret & __NET_XMIT_BYPASS)
198 qdisc_qstats_drop(sch);
199 __qdisc_drop(skb, to_free);
200 return ret;
201 }
202 idx--;
203
204 codel_set_enqueue_time(skb);
205 flow = &q->flows[idx];
206 flow_queue_add(flow, skb);
207 WRITE_ONCE(q->backlogs[idx], q->backlogs[idx] + qdisc_pkt_len(skb));
208 qdisc_qstats_backlog_inc(sch, skb);
209
210 if (list_empty(&flow->flowchain)) {
211 list_add_tail(&flow->flowchain, &q->new_flows);
212 q->new_flow_count++;
213 WRITE_ONCE(flow->deficit, q->quantum);
214 }
215 get_codel_cb(skb)->mem_usage = is_skb_wmem(skb) ? 0 : skb->truesize;
216 q->memory_usage += get_codel_cb(skb)->mem_usage;
217 memory_limited = q->memory_usage > q->memory_limit;
218 qdisc_qlen_inc(sch);
219 if (sch->q.qlen <= sch->limit && !memory_limited)
220 return NET_XMIT_SUCCESS;
221
222 prev_backlog = sch->qstats.backlog;
223 prev_qlen = sch->q.qlen;
224
225 /* save this packet length as it might be dropped by fq_codel_drop() */
226 pkt_len = qdisc_pkt_len(skb);
227 /* fq_codel_drop() is quite expensive, as it performs a linear search
228 * in q->backlogs[] to find a fat flow.
229 * So instead of dropping a single packet, drop half of its backlog
230 * with a 64 packets limit to not add a too big cpu spike here.
231 */
232 ret = fq_codel_drop(sch, q->drop_batch_size, to_free);
233
234 prev_qlen -= sch->q.qlen;
235 prev_backlog -= sch->qstats.backlog;
236 q->drop_overlimit += prev_qlen;
237 if (memory_limited)
238 q->drop_overmemory += prev_qlen;
239
240 /* As we dropped packet(s), better let upper stack know this.
241 * If we dropped a packet for this flow, return NET_XMIT_CN,
242 * but in this case, our parents wont increase their backlogs.
243 */
244 if (ret == idx) {
245 qdisc_tree_reduce_backlog(sch, prev_qlen - 1,
246 prev_backlog - pkt_len);
247 return NET_XMIT_CN;
248 }
249 qdisc_tree_reduce_backlog(sch, prev_qlen, prev_backlog);
250 return NET_XMIT_SUCCESS;
251 }
252
253 /* This is the specific function called from codel_dequeue()
254 * to dequeue a packet from queue. Note: backlog is handled in
255 * codel, we dont need to reduce it here.
256 */
dequeue_func(struct codel_vars * vars,void * ctx)257 static struct sk_buff *dequeue_func(struct codel_vars *vars, void *ctx)
258 {
259 struct Qdisc *sch = ctx;
260 struct fq_codel_sched_data *q = qdisc_priv(sch);
261 struct fq_codel_flow *flow;
262 struct sk_buff *skb = NULL;
263
264 flow = container_of(vars, struct fq_codel_flow, cvars);
265 if (flow->head) {
266 skb = dequeue_head(flow);
267 WRITE_ONCE(q->backlogs[flow - q->flows],
268 q->backlogs[flow - q->flows] - qdisc_pkt_len(skb));
269 q->memory_usage -= get_codel_cb(skb)->mem_usage;
270 qdisc_qlen_dec(sch);
271 qdisc_qstats_backlog_dec(sch, skb);
272 }
273 return skb;
274 }
275
drop_func(struct sk_buff * skb,void * ctx)276 static void drop_func(struct sk_buff *skb, void *ctx)
277 {
278 struct Qdisc *sch = ctx;
279
280 qdisc_dequeue_drop(sch, skb, QDISC_DROP_CONGESTED);
281 qdisc_qstats_drop(sch);
282 }
283
__fq_codel_dequeue(struct Qdisc * sch)284 static struct sk_buff *__fq_codel_dequeue(struct Qdisc *sch)
285 {
286 struct fq_codel_sched_data *q = qdisc_priv(sch);
287 struct sk_buff *skb;
288 struct fq_codel_flow *flow;
289 struct list_head *head;
290
291 begin:
292 head = &q->new_flows;
293 if (list_empty(head)) {
294 head = &q->old_flows;
295 if (list_empty(head))
296 return NULL;
297 }
298 flow = list_first_entry(head, struct fq_codel_flow, flowchain);
299
300 if (flow->deficit <= 0) {
301 WRITE_ONCE(flow->deficit, flow->deficit + q->quantum);
302 list_move_tail(&flow->flowchain, &q->old_flows);
303 goto begin;
304 }
305
306 skb = codel_dequeue(sch, &sch->qstats.backlog, &q->cparams,
307 &flow->cvars, &q->cstats, qdisc_pkt_len,
308 codel_get_enqueue_time, drop_func, dequeue_func);
309
310 if (!skb) {
311 /* force a pass through old_flows to prevent starvation */
312 if ((head == &q->new_flows) && !list_empty(&q->old_flows))
313 list_move_tail(&flow->flowchain, &q->old_flows);
314 else
315 list_del_init(&flow->flowchain);
316 goto begin;
317 }
318 qdisc_bstats_update(sch, skb);
319 WRITE_ONCE(flow->deficit, flow->deficit - qdisc_pkt_len(skb));
320
321 return skb;
322 }
323
fq_codel_dequeue_drop(struct Qdisc * sch)324 static void fq_codel_dequeue_drop(struct Qdisc *sch)
325 {
326 struct fq_codel_sched_data *q = qdisc_priv(sch);
327
328 if (q->cstats.drop_count) {
329 qdisc_tree_reduce_backlog(sch, q->cstats.drop_count,
330 q->cstats.drop_len);
331 q->cstats.drop_count = 0;
332 q->cstats.drop_len = 0;
333 }
334 }
335
fq_codel_dequeue(struct Qdisc * sch)336 static struct sk_buff *fq_codel_dequeue(struct Qdisc *sch)
337 {
338 struct sk_buff *skb;
339
340 skb = __fq_codel_dequeue(sch);
341
342 fq_codel_dequeue_drop(sch);
343
344 return skb;
345 }
346
fq_codel_peek(struct Qdisc * sch)347 static struct sk_buff *fq_codel_peek(struct Qdisc *sch)
348 {
349 struct sk_buff *skb = skb_peek(&sch->gso_skb);
350
351 if (!skb) {
352 skb = __fq_codel_dequeue(sch);
353
354 if (skb) {
355 __skb_queue_head(&sch->gso_skb, skb);
356 /* it's still part of the queue */
357 qdisc_qstats_backlog_inc(sch, skb);
358 sch->q.qlen++;
359 }
360
361 fq_codel_dequeue_drop(sch);
362 }
363
364 return skb;
365 }
366
fq_codel_flow_purge(struct fq_codel_flow * flow)367 static void fq_codel_flow_purge(struct fq_codel_flow *flow)
368 {
369 rtnl_kfree_skbs(flow->head, flow->tail);
370 WRITE_ONCE(flow->head, NULL);
371 }
372
fq_codel_reset(struct Qdisc * sch)373 static void fq_codel_reset(struct Qdisc *sch)
374 {
375 struct fq_codel_sched_data *q = qdisc_priv(sch);
376 int i;
377
378 INIT_LIST_HEAD(&q->new_flows);
379 INIT_LIST_HEAD(&q->old_flows);
380 for (i = 0; i < q->flows_cnt; i++) {
381 struct fq_codel_flow *flow = q->flows + i;
382
383 fq_codel_flow_purge(flow);
384 INIT_LIST_HEAD(&flow->flowchain);
385 codel_vars_init(&flow->cvars);
386 }
387 memset(q->backlogs, 0, q->flows_cnt * sizeof(u32));
388 q->memory_usage = 0;
389 }
390
391 static const struct nla_policy fq_codel_policy[TCA_FQ_CODEL_MAX + 1] = {
392 [TCA_FQ_CODEL_TARGET] = { .type = NLA_U32 },
393 [TCA_FQ_CODEL_LIMIT] = { .type = NLA_U32 },
394 [TCA_FQ_CODEL_INTERVAL] = { .type = NLA_U32 },
395 [TCA_FQ_CODEL_ECN] = { .type = NLA_U32 },
396 [TCA_FQ_CODEL_FLOWS] = { .type = NLA_U32 },
397 [TCA_FQ_CODEL_QUANTUM] = { .type = NLA_U32 },
398 [TCA_FQ_CODEL_CE_THRESHOLD] = { .type = NLA_U32 },
399 [TCA_FQ_CODEL_DROP_BATCH_SIZE] = { .type = NLA_U32 },
400 [TCA_FQ_CODEL_MEMORY_LIMIT] = { .type = NLA_U32 },
401 [TCA_FQ_CODEL_CE_THRESHOLD_SELECTOR] = { .type = NLA_U8 },
402 [TCA_FQ_CODEL_CE_THRESHOLD_MASK] = { .type = NLA_U8 },
403 };
404
fq_codel_change(struct Qdisc * sch,struct nlattr * opt,struct netlink_ext_ack * extack)405 static int fq_codel_change(struct Qdisc *sch, struct nlattr *opt,
406 struct netlink_ext_ack *extack)
407 {
408 unsigned int dropped_pkts = 0, dropped_bytes = 0;
409 struct fq_codel_sched_data *q = qdisc_priv(sch);
410 struct nlattr *tb[TCA_FQ_CODEL_MAX + 1];
411 u32 quantum = 0;
412 int err;
413
414 err = nla_parse_nested_deprecated(tb, TCA_FQ_CODEL_MAX, opt,
415 fq_codel_policy, NULL);
416 if (err < 0)
417 return err;
418 if (tb[TCA_FQ_CODEL_FLOWS]) {
419 if (q->flows)
420 return -EINVAL;
421 q->flows_cnt = nla_get_u32(tb[TCA_FQ_CODEL_FLOWS]);
422 if (!q->flows_cnt ||
423 q->flows_cnt > 65536)
424 return -EINVAL;
425 }
426 if (tb[TCA_FQ_CODEL_QUANTUM]) {
427 quantum = max(256U, nla_get_u32(tb[TCA_FQ_CODEL_QUANTUM]));
428 if (quantum > FQ_CODEL_QUANTUM_MAX) {
429 NL_SET_ERR_MSG(extack, "Invalid quantum");
430 return -EINVAL;
431 }
432 }
433 sch_tree_lock(sch);
434
435 if (tb[TCA_FQ_CODEL_TARGET]) {
436 u64 target = nla_get_u32(tb[TCA_FQ_CODEL_TARGET]);
437
438 WRITE_ONCE(q->cparams.target,
439 (target * NSEC_PER_USEC) >> CODEL_SHIFT);
440 }
441
442 if (tb[TCA_FQ_CODEL_CE_THRESHOLD]) {
443 u64 val = nla_get_u32(tb[TCA_FQ_CODEL_CE_THRESHOLD]);
444
445 WRITE_ONCE(q->cparams.ce_threshold,
446 (val * NSEC_PER_USEC) >> CODEL_SHIFT);
447 }
448
449 if (tb[TCA_FQ_CODEL_CE_THRESHOLD_SELECTOR])
450 WRITE_ONCE(q->cparams.ce_threshold_selector,
451 nla_get_u8(tb[TCA_FQ_CODEL_CE_THRESHOLD_SELECTOR]));
452 if (tb[TCA_FQ_CODEL_CE_THRESHOLD_MASK])
453 WRITE_ONCE(q->cparams.ce_threshold_mask,
454 nla_get_u8(tb[TCA_FQ_CODEL_CE_THRESHOLD_MASK]));
455
456 if (tb[TCA_FQ_CODEL_INTERVAL]) {
457 u64 interval = nla_get_u32(tb[TCA_FQ_CODEL_INTERVAL]);
458
459 WRITE_ONCE(q->cparams.interval,
460 (interval * NSEC_PER_USEC) >> CODEL_SHIFT);
461 }
462
463 if (tb[TCA_FQ_CODEL_LIMIT])
464 WRITE_ONCE(sch->limit,
465 nla_get_u32(tb[TCA_FQ_CODEL_LIMIT]));
466
467 if (tb[TCA_FQ_CODEL_ECN])
468 WRITE_ONCE(q->cparams.ecn,
469 !!nla_get_u32(tb[TCA_FQ_CODEL_ECN]));
470
471 if (quantum)
472 WRITE_ONCE(q->quantum, quantum);
473
474 if (tb[TCA_FQ_CODEL_DROP_BATCH_SIZE])
475 WRITE_ONCE(q->drop_batch_size,
476 max(1U, nla_get_u32(tb[TCA_FQ_CODEL_DROP_BATCH_SIZE])));
477
478 if (tb[TCA_FQ_CODEL_MEMORY_LIMIT])
479 WRITE_ONCE(q->memory_limit,
480 min(1U << 31, nla_get_u32(tb[TCA_FQ_CODEL_MEMORY_LIMIT])));
481
482 while (sch->q.qlen > sch->limit ||
483 q->memory_usage > q->memory_limit) {
484 struct sk_buff *skb = qdisc_dequeue_internal(sch, false);
485
486 if (!skb)
487 break;
488
489 dropped_pkts++;
490 dropped_bytes += qdisc_pkt_len(skb);
491 rtnl_kfree_skbs(skb, skb);
492 }
493 qdisc_tree_reduce_backlog(sch, dropped_pkts, dropped_bytes);
494
495 sch_tree_unlock(sch);
496 return 0;
497 }
498
fq_codel_destroy(struct Qdisc * sch)499 static void fq_codel_destroy(struct Qdisc *sch)
500 {
501 struct fq_codel_sched_data *q = qdisc_priv(sch);
502
503 tcf_block_put(q->block);
504 kvfree(q->backlogs);
505 kvfree(q->flows);
506 }
507
fq_codel_init(struct Qdisc * sch,struct nlattr * opt,struct netlink_ext_ack * extack)508 static int fq_codel_init(struct Qdisc *sch, struct nlattr *opt,
509 struct netlink_ext_ack *extack)
510 {
511 struct fq_codel_sched_data *q = qdisc_priv(sch);
512 int i;
513 int err;
514
515 sch->limit = 10*1024;
516 q->flows_cnt = 1024;
517 q->memory_limit = 32 << 20; /* 32 MBytes */
518 q->drop_batch_size = 64;
519 q->quantum = psched_mtu(qdisc_dev(sch));
520 INIT_LIST_HEAD(&q->new_flows);
521 INIT_LIST_HEAD(&q->old_flows);
522 codel_params_init(&q->cparams);
523 codel_stats_init(&q->cstats);
524 q->cparams.ecn = true;
525 q->cparams.mtu = psched_mtu(qdisc_dev(sch));
526
527 if (opt) {
528 err = fq_codel_change(sch, opt, extack);
529 if (err)
530 goto init_failure;
531 }
532
533 err = tcf_block_get(&q->block, &q->filter_list, sch, extack);
534 if (err)
535 goto init_failure;
536
537 if (!q->flows) {
538 q->flows = kvzalloc_objs(struct fq_codel_flow, q->flows_cnt);
539 if (!q->flows) {
540 err = -ENOMEM;
541 goto init_failure;
542 }
543 q->backlogs = kvcalloc(q->flows_cnt, sizeof(u32), GFP_KERNEL);
544 if (!q->backlogs) {
545 err = -ENOMEM;
546 goto alloc_failure;
547 }
548 for (i = 0; i < q->flows_cnt; i++) {
549 struct fq_codel_flow *flow = q->flows + i;
550
551 INIT_LIST_HEAD(&flow->flowchain);
552 codel_vars_init(&flow->cvars);
553 }
554 }
555 if (sch->limit >= 1)
556 sch->flags |= TCQ_F_CAN_BYPASS;
557 else
558 sch->flags &= ~TCQ_F_CAN_BYPASS;
559
560 sch->flags |= TCQ_F_DEQUEUE_DROPS;
561
562 return 0;
563
564 alloc_failure:
565 kvfree(q->flows);
566 q->flows = NULL;
567 init_failure:
568 q->flows_cnt = 0;
569 return err;
570 }
571
fq_codel_dump(struct Qdisc * sch,struct sk_buff * skb)572 static int fq_codel_dump(struct Qdisc *sch, struct sk_buff *skb)
573 {
574 struct fq_codel_sched_data *q = qdisc_priv(sch);
575 codel_time_t ce_threshold;
576 struct nlattr *opts;
577
578 opts = nla_nest_start_noflag(skb, TCA_OPTIONS);
579 if (opts == NULL)
580 goto nla_put_failure;
581
582 if (nla_put_u32(skb, TCA_FQ_CODEL_TARGET,
583 codel_time_to_us(READ_ONCE(q->cparams.target))) ||
584 nla_put_u32(skb, TCA_FQ_CODEL_LIMIT,
585 READ_ONCE(sch->limit)) ||
586 nla_put_u32(skb, TCA_FQ_CODEL_INTERVAL,
587 codel_time_to_us(READ_ONCE(q->cparams.interval))) ||
588 nla_put_u32(skb, TCA_FQ_CODEL_ECN,
589 READ_ONCE(q->cparams.ecn)) ||
590 nla_put_u32(skb, TCA_FQ_CODEL_QUANTUM,
591 READ_ONCE(q->quantum)) ||
592 nla_put_u32(skb, TCA_FQ_CODEL_DROP_BATCH_SIZE,
593 READ_ONCE(q->drop_batch_size)) ||
594 nla_put_u32(skb, TCA_FQ_CODEL_MEMORY_LIMIT,
595 READ_ONCE(q->memory_limit)) ||
596 nla_put_u32(skb, TCA_FQ_CODEL_FLOWS,
597 READ_ONCE(q->flows_cnt)))
598 goto nla_put_failure;
599
600 ce_threshold = READ_ONCE(q->cparams.ce_threshold);
601 if (ce_threshold != CODEL_DISABLED_THRESHOLD) {
602 if (nla_put_u32(skb, TCA_FQ_CODEL_CE_THRESHOLD,
603 codel_time_to_us(ce_threshold)))
604 goto nla_put_failure;
605 if (nla_put_u8(skb, TCA_FQ_CODEL_CE_THRESHOLD_SELECTOR,
606 READ_ONCE(q->cparams.ce_threshold_selector)))
607 goto nla_put_failure;
608 if (nla_put_u8(skb, TCA_FQ_CODEL_CE_THRESHOLD_MASK,
609 READ_ONCE(q->cparams.ce_threshold_mask)))
610 goto nla_put_failure;
611 }
612
613 return nla_nest_end(skb, opts);
614
615 nla_put_failure:
616 return -1;
617 }
618
fq_codel_dump_stats(struct Qdisc * sch,struct gnet_dump * d)619 static int fq_codel_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
620 {
621 struct fq_codel_sched_data *q = qdisc_priv(sch);
622 struct tc_fq_codel_xstats st = {
623 .type = TCA_FQ_CODEL_XSTATS_QDISC,
624 };
625 struct list_head *pos;
626
627 sch_tree_lock(sch);
628
629 st.qdisc_stats.maxpacket = q->cstats.maxpacket;
630 st.qdisc_stats.drop_overlimit = q->drop_overlimit;
631 st.qdisc_stats.ecn_mark = q->cstats.ecn_mark;
632 st.qdisc_stats.new_flow_count = q->new_flow_count;
633 st.qdisc_stats.ce_mark = q->cstats.ce_mark;
634 st.qdisc_stats.memory_usage = q->memory_usage;
635 st.qdisc_stats.drop_overmemory = q->drop_overmemory;
636
637 list_for_each(pos, &q->new_flows)
638 st.qdisc_stats.new_flows_len++;
639
640 list_for_each(pos, &q->old_flows)
641 st.qdisc_stats.old_flows_len++;
642 sch_tree_unlock(sch);
643
644 return gnet_stats_copy_app(d, &st, sizeof(st));
645 }
646
fq_codel_leaf(struct Qdisc * sch,unsigned long arg)647 static struct Qdisc *fq_codel_leaf(struct Qdisc *sch, unsigned long arg)
648 {
649 return NULL;
650 }
651
fq_codel_find(struct Qdisc * sch,u32 classid)652 static unsigned long fq_codel_find(struct Qdisc *sch, u32 classid)
653 {
654 return 0;
655 }
656
fq_codel_bind(struct Qdisc * sch,unsigned long parent,u32 classid)657 static unsigned long fq_codel_bind(struct Qdisc *sch, unsigned long parent,
658 u32 classid)
659 {
660 return 0;
661 }
662
fq_codel_unbind(struct Qdisc * q,unsigned long cl)663 static void fq_codel_unbind(struct Qdisc *q, unsigned long cl)
664 {
665 }
666
fq_codel_tcf_block(struct Qdisc * sch,unsigned long cl,struct netlink_ext_ack * extack)667 static struct tcf_block *fq_codel_tcf_block(struct Qdisc *sch, unsigned long cl,
668 struct netlink_ext_ack *extack)
669 {
670 struct fq_codel_sched_data *q = qdisc_priv(sch);
671
672 if (cl)
673 return NULL;
674 return q->block;
675 }
676
fq_codel_dump_class(struct Qdisc * sch,unsigned long cl,struct sk_buff * skb,struct tcmsg * tcm)677 static int fq_codel_dump_class(struct Qdisc *sch, unsigned long cl,
678 struct sk_buff *skb, struct tcmsg *tcm)
679 {
680 tcm->tcm_handle |= TC_H_MIN(cl);
681 return 0;
682 }
683
fq_codel_dump_class_stats(struct Qdisc * sch,unsigned long cl,struct gnet_dump * d)684 static int fq_codel_dump_class_stats(struct Qdisc *sch, unsigned long cl,
685 struct gnet_dump *d)
686 {
687 struct fq_codel_sched_data *q = qdisc_priv(sch);
688 u32 idx = cl - 1;
689 struct gnet_stats_queue qs = { 0 };
690 struct tc_fq_codel_xstats xstats;
691
692 if (idx < q->flows_cnt) {
693 const struct fq_codel_flow *flow = &q->flows[idx];
694 const struct sk_buff *skb;
695
696 memset(&xstats, 0, sizeof(xstats));
697 xstats.type = TCA_FQ_CODEL_XSTATS_CLASS;
698 xstats.class_stats.deficit = READ_ONCE(flow->deficit);
699 xstats.class_stats.ldelay =
700 codel_time_to_us(READ_ONCE(flow->cvars.ldelay));
701 xstats.class_stats.count = READ_ONCE(flow->cvars.count);
702 xstats.class_stats.lastcount = READ_ONCE(flow->cvars.lastcount);
703 xstats.class_stats.dropping = READ_ONCE(flow->cvars.dropping);
704 if (xstats.class_stats.dropping) {
705 codel_tdiff_t delta = READ_ONCE(flow->cvars.drop_next) -
706 codel_get_time();
707
708 xstats.class_stats.drop_next = (delta >= 0) ?
709 codel_time_to_us(delta) :
710 -codel_time_to_us(-delta);
711 }
712 if (READ_ONCE(flow->head)) {
713 sch_tree_lock(sch);
714 skb = flow->head;
715 while (skb) {
716 qs.qlen++;
717 skb = skb->next;
718 }
719 sch_tree_unlock(sch);
720 }
721 qs.backlog = READ_ONCE(q->backlogs[idx]);
722 qs.drops = 0;
723 }
724 if (gnet_stats_copy_queue(d, NULL, &qs, qs.qlen) < 0)
725 return -1;
726 if (idx < q->flows_cnt)
727 return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
728 return 0;
729 }
730
fq_codel_walk(struct Qdisc * sch,struct qdisc_walker * arg)731 static void fq_codel_walk(struct Qdisc *sch, struct qdisc_walker *arg)
732 {
733 struct fq_codel_sched_data *q = qdisc_priv(sch);
734 unsigned int i;
735
736 if (arg->stop)
737 return;
738
739 for (i = 0; i < q->flows_cnt; i++) {
740 if (list_empty(&q->flows[i].flowchain)) {
741 arg->count++;
742 continue;
743 }
744 if (!tc_qdisc_stats_dump(sch, i + 1, arg))
745 break;
746 }
747 }
748
749 static const struct Qdisc_class_ops fq_codel_class_ops = {
750 .leaf = fq_codel_leaf,
751 .find = fq_codel_find,
752 .tcf_block = fq_codel_tcf_block,
753 .bind_tcf = fq_codel_bind,
754 .unbind_tcf = fq_codel_unbind,
755 .dump = fq_codel_dump_class,
756 .dump_stats = fq_codel_dump_class_stats,
757 .walk = fq_codel_walk,
758 };
759
760 static struct Qdisc_ops fq_codel_qdisc_ops __read_mostly = {
761 .cl_ops = &fq_codel_class_ops,
762 .id = "fq_codel",
763 .priv_size = sizeof(struct fq_codel_sched_data),
764 .enqueue = fq_codel_enqueue,
765 .dequeue = fq_codel_dequeue,
766 .peek = fq_codel_peek,
767 .init = fq_codel_init,
768 .reset = fq_codel_reset,
769 .destroy = fq_codel_destroy,
770 .change = fq_codel_change,
771 .dump = fq_codel_dump,
772 .dump_stats = fq_codel_dump_stats,
773 .owner = THIS_MODULE,
774 };
775 MODULE_ALIAS_NET_SCH("fq_codel");
776
fq_codel_module_init(void)777 static int __init fq_codel_module_init(void)
778 {
779 return register_qdisc(&fq_codel_qdisc_ops);
780 }
781
fq_codel_module_exit(void)782 static void __exit fq_codel_module_exit(void)
783 {
784 unregister_qdisc(&fq_codel_qdisc_ops);
785 }
786
787 module_init(fq_codel_module_init)
788 module_exit(fq_codel_module_exit)
789 MODULE_AUTHOR("Eric Dumazet");
790 MODULE_LICENSE("GPL");
791 MODULE_DESCRIPTION("Fair Queue CoDel discipline");
792