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1// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
2
3/* COMMON Applications Kept Enhanced (CAKE) discipline
4 *
5 * Copyright (C) 2014-2018 Jonathan Morton <chromatix99@gmail.com>
6 * Copyright (C) 2015-2018 Toke Høiland-Jørgensen <toke@toke.dk>
7 * Copyright (C) 2014-2018 Dave Täht <dave.taht@gmail.com>
8 * Copyright (C) 2015-2018 Sebastian Moeller <moeller0@gmx.de>
9 * (C) 2015-2018 Kevin Darbyshire-Bryant <kevin@darbyshire-bryant.me.uk>
10 * Copyright (C) 2017-2018 Ryan Mounce <ryan@mounce.com.au>
11 *
12 * The CAKE Principles:
13 * (or, how to have your cake and eat it too)
14 *
15 * This is a combination of several shaping, AQM and FQ techniques into one
16 * easy-to-use package:
17 *
18 * - An overall bandwidth shaper, to move the bottleneck away from dumb CPE
19 * equipment and bloated MACs. This operates in deficit mode (as in sch_fq),
20 * eliminating the need for any sort of burst parameter (eg. token bucket
21 * depth). Burst support is limited to that necessary to overcome scheduling
22 * latency.
23 *
24 * - A Diffserv-aware priority queue, giving more priority to certain classes,
25 * up to a specified fraction of bandwidth. Above that bandwidth threshold,
26 * the priority is reduced to avoid starving other tins.
27 *
28 * - Each priority tin has a separate Flow Queue system, to isolate traffic
29 * flows from each other. This prevents a burst on one flow from increasing
30 * the delay to another. Flows are distributed to queues using a
31 * set-associative hash function.
32 *
33 * - Each queue is actively managed by Cobalt, which is a combination of the
34 * Codel and Blue AQM algorithms. This serves flows fairly, and signals
35 * congestion early via ECN (if available) and/or packet drops, to keep
36 * latency low. The codel parameters are auto-tuned based on the bandwidth
37 * setting, as is necessary at low bandwidths.
38 *
39 * The configuration parameters are kept deliberately simple for ease of use.
40 * Everything has sane defaults. Complete generality of configuration is *not*
41 * a goal.
42 *
43 * The priority queue operates according to a weighted DRR scheme, combined with
44 * a bandwidth tracker which reuses the shaper logic to detect which side of the
45 * bandwidth sharing threshold the tin is operating. This determines whether a
46 * priority-based weight (high) or a bandwidth-based weight (low) is used for
47 * that tin in the current pass.
48 *
49 * This qdisc was inspired by Eric Dumazet's fq_codel code, which he kindly
50 * granted us permission to leverage.
51 */
52
53#include <linux/module.h>
54#include <linux/types.h>
55#include <linux/kernel.h>
56#include <linux/jiffies.h>
57#include <linux/string.h>
58#include <linux/in.h>
59#include <linux/errno.h>
60#include <linux/init.h>
61#include <linux/skbuff.h>
62#include <linux/jhash.h>
63#include <linux/slab.h>
64#include <linux/vmalloc.h>
65#include <linux/reciprocal_div.h>
66#include <net/netlink.h>
67#include <linux/if_vlan.h>
68#include <net/gso.h>
69#include <net/pkt_sched.h>
70#include <net/pkt_cls.h>
71#include <net/tcp.h>
72#include <net/flow_dissector.h>
73
74#if IS_ENABLED(CONFIG_NF_CONNTRACK)
75#include <net/netfilter/nf_conntrack_core.h>
76#endif
77
78#define CAKE_SET_WAYS (8)
79#define CAKE_MAX_TINS (8)
80#define CAKE_QUEUES (1024)
81#define CAKE_FLOW_MASK 63
82#define CAKE_FLOW_NAT_FLAG 64
83
84/* struct cobalt_params - contains codel and blue parameters
85 * @interval: codel initial drop rate
86 * @target: maximum persistent sojourn time & blue update rate
87 * @mtu_time: serialisation delay of maximum-size packet
88 * @p_inc: increment of blue drop probability (0.32 fxp)
89 * @p_dec: decrement of blue drop probability (0.32 fxp)
90 */
91struct cobalt_params {
92 u64 interval;
93 u64 target;
94 u64 mtu_time;
95 u32 p_inc;
96 u32 p_dec;
97};
98
99/* struct cobalt_vars - contains codel and blue variables
100 * @count: codel dropping frequency
101 * @rec_inv_sqrt: reciprocal value of sqrt(count) >> 1
102 * @drop_next: time to drop next packet, or when we dropped last
103 * @blue_timer: Blue time to next drop
104 * @p_drop: BLUE drop probability (0.32 fxp)
105 * @dropping: set if in dropping state
106 * @ecn_marked: set if marked
107 */
108struct cobalt_vars {
109 u32 count;
110 u32 rec_inv_sqrt;
111 ktime_t drop_next;
112 ktime_t blue_timer;
113 u32 p_drop;
114 bool dropping;
115 bool ecn_marked;
116};
117
118enum {
119 CAKE_SET_NONE = 0,
120 CAKE_SET_SPARSE,
121 CAKE_SET_SPARSE_WAIT, /* counted in SPARSE, actually in BULK */
122 CAKE_SET_BULK,
123 CAKE_SET_DECAYING
124};
125
126struct cake_flow {
127 /* this stuff is all needed per-flow at dequeue time */
128 struct sk_buff *head;
129 struct sk_buff *tail;
130 struct list_head flowchain;
131 s32 deficit;
132 u32 dropped;
133 struct cobalt_vars cvars;
134 u16 srchost; /* index into cake_host table */
135 u16 dsthost;
136 u8 set;
137}; /* please try to keep this structure <= 64 bytes */
138
139struct cake_host {
140 u32 srchost_tag;
141 u32 dsthost_tag;
142 u16 srchost_bulk_flow_count;
143 u16 dsthost_bulk_flow_count;
144};
145
146struct cake_heap_entry {
147 u16 t:3, b:10;
148};
149
150struct cake_tin_data {
151 struct cake_flow flows[CAKE_QUEUES];
152 u32 backlogs[CAKE_QUEUES];
153 u32 tags[CAKE_QUEUES]; /* for set association */
154 u16 overflow_idx[CAKE_QUEUES];
155 struct cake_host hosts[CAKE_QUEUES]; /* for triple isolation */
156 u16 flow_quantum;
157
158 struct cobalt_params cparams;
159 u32 drop_overlimit;
160 u16 bulk_flow_count;
161 u16 sparse_flow_count;
162 u16 decaying_flow_count;
163 u16 unresponsive_flow_count;
164
165 u32 max_skblen;
166
167 struct list_head new_flows;
168 struct list_head old_flows;
169 struct list_head decaying_flows;
170
171 /* time_next = time_this + ((len * rate_ns) >> rate_shft) */
172 ktime_t time_next_packet;
173 u64 tin_rate_ns;
174 u64 tin_rate_bps;
175 u16 tin_rate_shft;
176
177 u16 tin_quantum;
178 s32 tin_deficit;
179 u32 tin_backlog;
180 u32 tin_dropped;
181 u32 tin_ecn_mark;
182
183 u32 packets;
184 u64 bytes;
185
186 u32 ack_drops;
187
188 /* moving averages */
189 u64 avge_delay;
190 u64 peak_delay;
191 u64 base_delay;
192
193 /* hash function stats */
194 u32 way_directs;
195 u32 way_hits;
196 u32 way_misses;
197 u32 way_collisions;
198}; /* number of tins is small, so size of this struct doesn't matter much */
199
200struct cake_sched_data {
201 struct tcf_proto __rcu *filter_list; /* optional external classifier */
202 struct tcf_block *block;
203 struct cake_tin_data *tins;
204
205 struct cake_heap_entry overflow_heap[CAKE_QUEUES * CAKE_MAX_TINS];
206 u16 overflow_timeout;
207
208 u16 tin_cnt;
209 u8 tin_mode;
210 u8 flow_mode;
211 u8 ack_filter;
212 u8 atm_mode;
213
214 u32 fwmark_mask;
215 u16 fwmark_shft;
216
217 /* time_next = time_this + ((len * rate_ns) >> rate_shft) */
218 u16 rate_shft;
219 ktime_t time_next_packet;
220 ktime_t failsafe_next_packet;
221 u64 rate_ns;
222 u64 rate_bps;
223 u16 rate_flags;
224 s16 rate_overhead;
225 u16 rate_mpu;
226 u64 interval;
227 u64 target;
228
229 /* resource tracking */
230 u32 buffer_used;
231 u32 buffer_max_used;
232 u32 buffer_limit;
233 u32 buffer_config_limit;
234
235 /* indices for dequeue */
236 u16 cur_tin;
237 u16 cur_flow;
238
239 struct qdisc_watchdog watchdog;
240 const u8 *tin_index;
241 const u8 *tin_order;
242
243 /* bandwidth capacity estimate */
244 ktime_t last_packet_time;
245 ktime_t avg_window_begin;
246 u64 avg_packet_interval;
247 u64 avg_window_bytes;
248 u64 avg_peak_bandwidth;
249 ktime_t last_reconfig_time;
250
251 /* packet length stats */
252 u32 avg_netoff;
253 u16 max_netlen;
254 u16 max_adjlen;
255 u16 min_netlen;
256 u16 min_adjlen;
257};
258
259enum {
260 CAKE_FLAG_OVERHEAD = BIT(0),
261 CAKE_FLAG_AUTORATE_INGRESS = BIT(1),
262 CAKE_FLAG_INGRESS = BIT(2),
263 CAKE_FLAG_WASH = BIT(3),
264 CAKE_FLAG_SPLIT_GSO = BIT(4)
265};
266
267/* COBALT operates the Codel and BLUE algorithms in parallel, in order to
268 * obtain the best features of each. Codel is excellent on flows which
269 * respond to congestion signals in a TCP-like way. BLUE is more effective on
270 * unresponsive flows.
271 */
272
273struct cobalt_skb_cb {
274 ktime_t enqueue_time;
275 u32 adjusted_len;
276};
277
278static u64 us_to_ns(u64 us)
279{
280 return us * NSEC_PER_USEC;
281}
282
283static struct cobalt_skb_cb *get_cobalt_cb(const struct sk_buff *skb)
284{
285 qdisc_cb_private_validate(skb, sizeof(struct cobalt_skb_cb));
286 return (struct cobalt_skb_cb *)qdisc_skb_cb(skb)->data;
287}
288
289static ktime_t cobalt_get_enqueue_time(const struct sk_buff *skb)
290{
291 return get_cobalt_cb(skb)->enqueue_time;
292}
293
294static void cobalt_set_enqueue_time(struct sk_buff *skb,
295 ktime_t now)
296{
297 get_cobalt_cb(skb)->enqueue_time = now;
298}
299
300static u16 quantum_div[CAKE_QUEUES + 1] = {0};
301
302/* Diffserv lookup tables */
303
304static const u8 precedence[] = {
305 0, 0, 0, 0, 0, 0, 0, 0,
306 1, 1, 1, 1, 1, 1, 1, 1,
307 2, 2, 2, 2, 2, 2, 2, 2,
308 3, 3, 3, 3, 3, 3, 3, 3,
309 4, 4, 4, 4, 4, 4, 4, 4,
310 5, 5, 5, 5, 5, 5, 5, 5,
311 6, 6, 6, 6, 6, 6, 6, 6,
312 7, 7, 7, 7, 7, 7, 7, 7,
313};
314
315static const u8 diffserv8[] = {
316 2, 0, 1, 2, 4, 2, 2, 2,
317 1, 2, 1, 2, 1, 2, 1, 2,
318 5, 2, 4, 2, 4, 2, 4, 2,
319 3, 2, 3, 2, 3, 2, 3, 2,
320 6, 2, 3, 2, 3, 2, 3, 2,
321 6, 2, 2, 2, 6, 2, 6, 2,
322 7, 2, 2, 2, 2, 2, 2, 2,
323 7, 2, 2, 2, 2, 2, 2, 2,
324};
325
326static const u8 diffserv4[] = {
327 0, 1, 0, 0, 2, 0, 0, 0,
328 1, 0, 0, 0, 0, 0, 0, 0,
329 2, 0, 2, 0, 2, 0, 2, 0,
330 2, 0, 2, 0, 2, 0, 2, 0,
331 3, 0, 2, 0, 2, 0, 2, 0,
332 3, 0, 0, 0, 3, 0, 3, 0,
333 3, 0, 0, 0, 0, 0, 0, 0,
334 3, 0, 0, 0, 0, 0, 0, 0,
335};
336
337static const u8 diffserv3[] = {
338 0, 1, 0, 0, 2, 0, 0, 0,
339 1, 0, 0, 0, 0, 0, 0, 0,
340 0, 0, 0, 0, 0, 0, 0, 0,
341 0, 0, 0, 0, 0, 0, 0, 0,
342 0, 0, 0, 0, 0, 0, 0, 0,
343 0, 0, 0, 0, 2, 0, 2, 0,
344 2, 0, 0, 0, 0, 0, 0, 0,
345 2, 0, 0, 0, 0, 0, 0, 0,
346};
347
348static const u8 besteffort[] = {
349 0, 0, 0, 0, 0, 0, 0, 0,
350 0, 0, 0, 0, 0, 0, 0, 0,
351 0, 0, 0, 0, 0, 0, 0, 0,
352 0, 0, 0, 0, 0, 0, 0, 0,
353 0, 0, 0, 0, 0, 0, 0, 0,
354 0, 0, 0, 0, 0, 0, 0, 0,
355 0, 0, 0, 0, 0, 0, 0, 0,
356 0, 0, 0, 0, 0, 0, 0, 0,
357};
358
359/* tin priority order for stats dumping */
360
361static const u8 normal_order[] = {0, 1, 2, 3, 4, 5, 6, 7};
362static const u8 bulk_order[] = {1, 0, 2, 3};
363
364/* There is a big difference in timing between the accurate values placed in the
365 * cache and the approximations given by a single Newton step for small count
366 * values, particularly when stepping from count 1 to 2 or vice versa. Hence,
367 * these values are calculated using eight Newton steps, using the
368 * implementation below. Above 16, a single Newton step gives sufficient
369 * accuracy in either direction, given the precision stored.
370 *
371 * The magnitude of the error when stepping up to count 2 is such as to give the
372 * value that *should* have been produced at count 4.
373 */
374
375#define REC_INV_SQRT_CACHE (16)
376static const u32 inv_sqrt_cache[REC_INV_SQRT_CACHE] = {
377 ~0, ~0, 3037000500, 2479700525,
378 2147483647, 1920767767, 1753413056, 1623345051,
379 1518500250, 1431655765, 1358187914, 1294981364,
380 1239850263, 1191209601, 1147878294, 1108955788
381};
382
383/* http://en.wikipedia.org/wiki/Methods_of_computing_square_roots
384 * new_invsqrt = (invsqrt / 2) * (3 - count * invsqrt^2)
385 *
386 * Here, invsqrt is a fixed point number (< 1.0), 32bit mantissa, aka Q0.32
387 */
388
389static void cobalt_newton_step(struct cobalt_vars *vars)
390{
391 u32 invsqrt, invsqrt2;
392 u64 val;
393
394 invsqrt = vars->rec_inv_sqrt;
395 invsqrt2 = ((u64)invsqrt * invsqrt) >> 32;
396 val = (3LL << 32) - ((u64)vars->count * invsqrt2);
397
398 val >>= 2; /* avoid overflow in following multiply */
399 val = (val * invsqrt) >> (32 - 2 + 1);
400
401 vars->rec_inv_sqrt = val;
402}
403
404static void cobalt_invsqrt(struct cobalt_vars *vars)
405{
406 if (vars->count < REC_INV_SQRT_CACHE)
407 vars->rec_inv_sqrt = inv_sqrt_cache[vars->count];
408 else
409 cobalt_newton_step(vars);
410}
411
412static void cobalt_vars_init(struct cobalt_vars *vars)
413{
414 memset(vars, 0, sizeof(*vars));
415}
416
417/* CoDel control_law is t + interval/sqrt(count)
418 * We maintain in rec_inv_sqrt the reciprocal value of sqrt(count) to avoid
419 * both sqrt() and divide operation.
420 */
421static ktime_t cobalt_control(ktime_t t,
422 u64 interval,
423 u32 rec_inv_sqrt)
424{
425 return ktime_add_ns(t, reciprocal_scale(interval,
426 rec_inv_sqrt));
427}
428
429/* Call this when a packet had to be dropped due to queue overflow. Returns
430 * true if the BLUE state was quiescent before but active after this call.
431 */
432static bool cobalt_queue_full(struct cobalt_vars *vars,
433 struct cobalt_params *p,
434 ktime_t now)
435{
436 bool up = false;
437
438 if (ktime_to_ns(ktime_sub(now, vars->blue_timer)) > p->target) {
439 up = !vars->p_drop;
440 vars->p_drop += p->p_inc;
441 if (vars->p_drop < p->p_inc)
442 vars->p_drop = ~0;
443 vars->blue_timer = now;
444 }
445 vars->dropping = true;
446 vars->drop_next = now;
447 if (!vars->count)
448 vars->count = 1;
449
450 return up;
451}
452
453/* Call this when the queue was serviced but turned out to be empty. Returns
454 * true if the BLUE state was active before but quiescent after this call.
455 */
456static bool cobalt_queue_empty(struct cobalt_vars *vars,
457 struct cobalt_params *p,
458 ktime_t now)
459{
460 bool down = false;
461
462 if (vars->p_drop &&
463 ktime_to_ns(ktime_sub(now, vars->blue_timer)) > p->target) {
464 if (vars->p_drop < p->p_dec)
465 vars->p_drop = 0;
466 else
467 vars->p_drop -= p->p_dec;
468 vars->blue_timer = now;
469 down = !vars->p_drop;
470 }
471 vars->dropping = false;
472
473 if (vars->count && ktime_to_ns(ktime_sub(now, vars->drop_next)) >= 0) {
474 vars->count--;
475 cobalt_invsqrt(vars);
476 vars->drop_next = cobalt_control(vars->drop_next,
477 p->interval,
478 vars->rec_inv_sqrt);
479 }
480
481 return down;
482}
483
484/* Call this with a freshly dequeued packet for possible congestion marking.
485 * Returns true as an instruction to drop the packet, false for delivery.
486 */
487static bool cobalt_should_drop(struct cobalt_vars *vars,
488 struct cobalt_params *p,
489 ktime_t now,
490 struct sk_buff *skb,
491 u32 bulk_flows)
492{
493 bool next_due, over_target, drop = false;
494 ktime_t schedule;
495 u64 sojourn;
496
497/* The 'schedule' variable records, in its sign, whether 'now' is before or
498 * after 'drop_next'. This allows 'drop_next' to be updated before the next
499 * scheduling decision is actually branched, without destroying that
500 * information. Similarly, the first 'schedule' value calculated is preserved
501 * in the boolean 'next_due'.
502 *
503 * As for 'drop_next', we take advantage of the fact that 'interval' is both
504 * the delay between first exceeding 'target' and the first signalling event,
505 * *and* the scaling factor for the signalling frequency. It's therefore very
506 * natural to use a single mechanism for both purposes, and eliminates a
507 * significant amount of reference Codel's spaghetti code. To help with this,
508 * both the '0' and '1' entries in the invsqrt cache are 0xFFFFFFFF, as close
509 * as possible to 1.0 in fixed-point.
510 */
511
512 sojourn = ktime_to_ns(ktime_sub(now, cobalt_get_enqueue_time(skb)));
513 schedule = ktime_sub(now, vars->drop_next);
514 over_target = sojourn > p->target &&
515 sojourn > p->mtu_time * bulk_flows * 2 &&
516 sojourn > p->mtu_time * 4;
517 next_due = vars->count && ktime_to_ns(schedule) >= 0;
518
519 vars->ecn_marked = false;
520
521 if (over_target) {
522 if (!vars->dropping) {
523 vars->dropping = true;
524 vars->drop_next = cobalt_control(now,
525 p->interval,
526 vars->rec_inv_sqrt);
527 }
528 if (!vars->count)
529 vars->count = 1;
530 } else if (vars->dropping) {
531 vars->dropping = false;
532 }
533
534 if (next_due && vars->dropping) {
535 /* Use ECN mark if possible, otherwise drop */
536 drop = !(vars->ecn_marked = INET_ECN_set_ce(skb));
537
538 vars->count++;
539 if (!vars->count)
540 vars->count--;
541 cobalt_invsqrt(vars);
542 vars->drop_next = cobalt_control(vars->drop_next,
543 p->interval,
544 vars->rec_inv_sqrt);
545 schedule = ktime_sub(now, vars->drop_next);
546 } else {
547 while (next_due) {
548 vars->count--;
549 cobalt_invsqrt(vars);
550 vars->drop_next = cobalt_control(vars->drop_next,
551 p->interval,
552 vars->rec_inv_sqrt);
553 schedule = ktime_sub(now, vars->drop_next);
554 next_due = vars->count && ktime_to_ns(schedule) >= 0;
555 }
556 }
557
558 /* Simple BLUE implementation. Lack of ECN is deliberate. */
559 if (vars->p_drop)
560 drop |= (get_random_u32() < vars->p_drop);
561
562 /* Overload the drop_next field as an activity timeout */
563 if (!vars->count)
564 vars->drop_next = ktime_add_ns(now, p->interval);
565 else if (ktime_to_ns(schedule) > 0 && !drop)
566 vars->drop_next = now;
567
568 return drop;
569}
570
571static bool cake_update_flowkeys(struct flow_keys *keys,
572 const struct sk_buff *skb)
573{
574#if IS_ENABLED(CONFIG_NF_CONNTRACK)
575 struct nf_conntrack_tuple tuple = {};
576 bool rev = !skb->_nfct, upd = false;
577 __be32 ip;
578
579 if (skb_protocol(skb, true) != htons(ETH_P_IP))
580 return false;
581
582 if (!nf_ct_get_tuple_skb(&tuple, skb))
583 return false;
584
585 ip = rev ? tuple.dst.u3.ip : tuple.src.u3.ip;
586 if (ip != keys->addrs.v4addrs.src) {
587 keys->addrs.v4addrs.src = ip;
588 upd = true;
589 }
590 ip = rev ? tuple.src.u3.ip : tuple.dst.u3.ip;
591 if (ip != keys->addrs.v4addrs.dst) {
592 keys->addrs.v4addrs.dst = ip;
593 upd = true;
594 }
595
596 if (keys->ports.ports) {
597 __be16 port;
598
599 port = rev ? tuple.dst.u.all : tuple.src.u.all;
600 if (port != keys->ports.src) {
601 keys->ports.src = port;
602 upd = true;
603 }
604 port = rev ? tuple.src.u.all : tuple.dst.u.all;
605 if (port != keys->ports.dst) {
606 port = keys->ports.dst;
607 upd = true;
608 }
609 }
610 return upd;
611#else
612 return false;
613#endif
614}
615
616/* Cake has several subtle multiple bit settings. In these cases you
617 * would be matching triple isolate mode as well.
618 */
619
620static bool cake_dsrc(int flow_mode)
621{
622 return (flow_mode & CAKE_FLOW_DUAL_SRC) == CAKE_FLOW_DUAL_SRC;
623}
624
625static bool cake_ddst(int flow_mode)
626{
627 return (flow_mode & CAKE_FLOW_DUAL_DST) == CAKE_FLOW_DUAL_DST;
628}
629
630static void cake_dec_srchost_bulk_flow_count(struct cake_tin_data *q,
631 struct cake_flow *flow,
632 int flow_mode)
633{
634 if (likely(cake_dsrc(flow_mode) &&
635 q->hosts[flow->srchost].srchost_bulk_flow_count))
636 q->hosts[flow->srchost].srchost_bulk_flow_count--;
637}
638
639static void cake_inc_srchost_bulk_flow_count(struct cake_tin_data *q,
640 struct cake_flow *flow,
641 int flow_mode)
642{
643 if (likely(cake_dsrc(flow_mode) &&
644 q->hosts[flow->srchost].srchost_bulk_flow_count < CAKE_QUEUES))
645 q->hosts[flow->srchost].srchost_bulk_flow_count++;
646}
647
648static void cake_dec_dsthost_bulk_flow_count(struct cake_tin_data *q,
649 struct cake_flow *flow,
650 int flow_mode)
651{
652 if (likely(cake_ddst(flow_mode) &&
653 q->hosts[flow->dsthost].dsthost_bulk_flow_count))
654 q->hosts[flow->dsthost].dsthost_bulk_flow_count--;
655}
656
657static void cake_inc_dsthost_bulk_flow_count(struct cake_tin_data *q,
658 struct cake_flow *flow,
659 int flow_mode)
660{
661 if (likely(cake_ddst(flow_mode) &&
662 q->hosts[flow->dsthost].dsthost_bulk_flow_count < CAKE_QUEUES))
663 q->hosts[flow->dsthost].dsthost_bulk_flow_count++;
664}
665
666static u16 cake_get_flow_quantum(struct cake_tin_data *q,
667 struct cake_flow *flow,
668 int flow_mode)
669{
670 u16 host_load = 1;
671
672 if (cake_dsrc(flow_mode))
673 host_load = max(host_load,
674 q->hosts[flow->srchost].srchost_bulk_flow_count);
675
676 if (cake_ddst(flow_mode))
677 host_load = max(host_load,
678 q->hosts[flow->dsthost].dsthost_bulk_flow_count);
679
680 /* The get_random_u16() is a way to apply dithering to avoid
681 * accumulating roundoff errors
682 */
683 return (q->flow_quantum * quantum_div[host_load] +
684 get_random_u16()) >> 16;
685}
686
687static u32 cake_hash(struct cake_tin_data *q, const struct sk_buff *skb,
688 int flow_mode, u16 flow_override, u16 host_override)
689{
690 bool hash_flows = (!flow_override && !!(flow_mode & CAKE_FLOW_FLOWS));
691 bool hash_hosts = (!host_override && !!(flow_mode & CAKE_FLOW_HOSTS));
692 bool nat_enabled = !!(flow_mode & CAKE_FLOW_NAT_FLAG);
693 u32 flow_hash = 0, srchost_hash = 0, dsthost_hash = 0;
694 u16 reduced_hash, srchost_idx, dsthost_idx;
695 struct flow_keys keys, host_keys;
696 bool use_skbhash = skb->l4_hash;
697
698 if (unlikely(flow_mode == CAKE_FLOW_NONE))
699 return 0;
700
701 /* If both overrides are set, or we can use the SKB hash and nat mode is
702 * disabled, we can skip packet dissection entirely. If nat mode is
703 * enabled there's another check below after doing the conntrack lookup.
704 */
705 if ((!hash_flows || (use_skbhash && !nat_enabled)) && !hash_hosts)
706 goto skip_hash;
707
708 skb_flow_dissect_flow_keys(skb, &keys,
709 FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL);
710
711 /* Don't use the SKB hash if we change the lookup keys from conntrack */
712 if (nat_enabled && cake_update_flowkeys(&keys, skb))
713 use_skbhash = false;
714
715 /* If we can still use the SKB hash and don't need the host hash, we can
716 * skip the rest of the hashing procedure
717 */
718 if (use_skbhash && !hash_hosts)
719 goto skip_hash;
720
721 /* flow_hash_from_keys() sorts the addresses by value, so we have
722 * to preserve their order in a separate data structure to treat
723 * src and dst host addresses as independently selectable.
724 */
725 host_keys = keys;
726 host_keys.ports.ports = 0;
727 host_keys.basic.ip_proto = 0;
728 host_keys.keyid.keyid = 0;
729 host_keys.tags.flow_label = 0;
730
731 switch (host_keys.control.addr_type) {
732 case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
733 host_keys.addrs.v4addrs.src = 0;
734 dsthost_hash = flow_hash_from_keys(&host_keys);
735 host_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
736 host_keys.addrs.v4addrs.dst = 0;
737 srchost_hash = flow_hash_from_keys(&host_keys);
738 break;
739
740 case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
741 memset(&host_keys.addrs.v6addrs.src, 0,
742 sizeof(host_keys.addrs.v6addrs.src));
743 dsthost_hash = flow_hash_from_keys(&host_keys);
744 host_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src;
745 memset(&host_keys.addrs.v6addrs.dst, 0,
746 sizeof(host_keys.addrs.v6addrs.dst));
747 srchost_hash = flow_hash_from_keys(&host_keys);
748 break;
749
750 default:
751 dsthost_hash = 0;
752 srchost_hash = 0;
753 }
754
755 /* This *must* be after the above switch, since as a
756 * side-effect it sorts the src and dst addresses.
757 */
758 if (hash_flows && !use_skbhash)
759 flow_hash = flow_hash_from_keys(&keys);
760
761skip_hash:
762 if (flow_override)
763 flow_hash = flow_override - 1;
764 else if (use_skbhash && (flow_mode & CAKE_FLOW_FLOWS))
765 flow_hash = skb->hash;
766 if (host_override) {
767 dsthost_hash = host_override - 1;
768 srchost_hash = host_override - 1;
769 }
770
771 if (!(flow_mode & CAKE_FLOW_FLOWS)) {
772 if (flow_mode & CAKE_FLOW_SRC_IP)
773 flow_hash ^= srchost_hash;
774
775 if (flow_mode & CAKE_FLOW_DST_IP)
776 flow_hash ^= dsthost_hash;
777 }
778
779 reduced_hash = flow_hash % CAKE_QUEUES;
780
781 /* set-associative hashing */
782 /* fast path if no hash collision (direct lookup succeeds) */
783 if (likely(q->tags[reduced_hash] == flow_hash &&
784 q->flows[reduced_hash].set)) {
785 q->way_directs++;
786 } else {
787 u32 inner_hash = reduced_hash % CAKE_SET_WAYS;
788 u32 outer_hash = reduced_hash - inner_hash;
789 bool allocate_src = false;
790 bool allocate_dst = false;
791 u32 i, k;
792
793 /* check if any active queue in the set is reserved for
794 * this flow.
795 */
796 for (i = 0, k = inner_hash; i < CAKE_SET_WAYS;
797 i++, k = (k + 1) % CAKE_SET_WAYS) {
798 if (q->tags[outer_hash + k] == flow_hash) {
799 if (i)
800 q->way_hits++;
801
802 if (!q->flows[outer_hash + k].set) {
803 /* need to increment host refcnts */
804 allocate_src = cake_dsrc(flow_mode);
805 allocate_dst = cake_ddst(flow_mode);
806 }
807
808 goto found;
809 }
810 }
811
812 /* no queue is reserved for this flow, look for an
813 * empty one.
814 */
815 for (i = 0; i < CAKE_SET_WAYS;
816 i++, k = (k + 1) % CAKE_SET_WAYS) {
817 if (!q->flows[outer_hash + k].set) {
818 q->way_misses++;
819 allocate_src = cake_dsrc(flow_mode);
820 allocate_dst = cake_ddst(flow_mode);
821 goto found;
822 }
823 }
824
825 /* With no empty queues, default to the original
826 * queue, accept the collision, update the host tags.
827 */
828 q->way_collisions++;
829 allocate_src = cake_dsrc(flow_mode);
830 allocate_dst = cake_ddst(flow_mode);
831
832 if (q->flows[outer_hash + k].set == CAKE_SET_BULK) {
833 cake_dec_srchost_bulk_flow_count(q, &q->flows[outer_hash + k], flow_mode);
834 cake_dec_dsthost_bulk_flow_count(q, &q->flows[outer_hash + k], flow_mode);
835 }
836found:
837 /* reserve queue for future packets in same flow */
838 reduced_hash = outer_hash + k;
839 q->tags[reduced_hash] = flow_hash;
840
841 if (allocate_src) {
842 srchost_idx = srchost_hash % CAKE_QUEUES;
843 inner_hash = srchost_idx % CAKE_SET_WAYS;
844 outer_hash = srchost_idx - inner_hash;
845 for (i = 0, k = inner_hash; i < CAKE_SET_WAYS;
846 i++, k = (k + 1) % CAKE_SET_WAYS) {
847 if (q->hosts[outer_hash + k].srchost_tag ==
848 srchost_hash)
849 goto found_src;
850 }
851 for (i = 0; i < CAKE_SET_WAYS;
852 i++, k = (k + 1) % CAKE_SET_WAYS) {
853 if (!q->hosts[outer_hash + k].srchost_bulk_flow_count)
854 break;
855 }
856 q->hosts[outer_hash + k].srchost_tag = srchost_hash;
857found_src:
858 srchost_idx = outer_hash + k;
859 q->flows[reduced_hash].srchost = srchost_idx;
860
861 if (q->flows[reduced_hash].set == CAKE_SET_BULK)
862 cake_inc_srchost_bulk_flow_count(q, &q->flows[reduced_hash], flow_mode);
863 }
864
865 if (allocate_dst) {
866 dsthost_idx = dsthost_hash % CAKE_QUEUES;
867 inner_hash = dsthost_idx % CAKE_SET_WAYS;
868 outer_hash = dsthost_idx - inner_hash;
869 for (i = 0, k = inner_hash; i < CAKE_SET_WAYS;
870 i++, k = (k + 1) % CAKE_SET_WAYS) {
871 if (q->hosts[outer_hash + k].dsthost_tag ==
872 dsthost_hash)
873 goto found_dst;
874 }
875 for (i = 0; i < CAKE_SET_WAYS;
876 i++, k = (k + 1) % CAKE_SET_WAYS) {
877 if (!q->hosts[outer_hash + k].dsthost_bulk_flow_count)
878 break;
879 }
880 q->hosts[outer_hash + k].dsthost_tag = dsthost_hash;
881found_dst:
882 dsthost_idx = outer_hash + k;
883 q->flows[reduced_hash].dsthost = dsthost_idx;
884
885 if (q->flows[reduced_hash].set == CAKE_SET_BULK)
886 cake_inc_dsthost_bulk_flow_count(q, &q->flows[reduced_hash], flow_mode);
887 }
888 }
889
890 return reduced_hash;
891}
892
893/* helper functions : might be changed when/if skb use a standard list_head */
894/* remove one skb from head of slot queue */
895
896static struct sk_buff *dequeue_head(struct cake_flow *flow)
897{
898 struct sk_buff *skb = flow->head;
899
900 if (skb) {
901 flow->head = skb->next;
902 skb_mark_not_on_list(skb);
903 }
904
905 return skb;
906}
907
908/* add skb to flow queue (tail add) */
909
910static void flow_queue_add(struct cake_flow *flow, struct sk_buff *skb)
911{
912 if (!flow->head)
913 flow->head = skb;
914 else
915 flow->tail->next = skb;
916 flow->tail = skb;
917 skb->next = NULL;
918}
919
920static struct iphdr *cake_get_iphdr(const struct sk_buff *skb,
921 struct ipv6hdr *buf)
922{
923 unsigned int offset = skb_network_offset(skb);
924 struct iphdr *iph;
925
926 iph = skb_header_pointer(skb, offset, sizeof(struct iphdr), buf);
927
928 if (!iph)
929 return NULL;
930
931 if (iph->version == 4 && iph->protocol == IPPROTO_IPV6)
932 return skb_header_pointer(skb, offset + iph->ihl * 4,
933 sizeof(struct ipv6hdr), buf);
934
935 else if (iph->version == 4)
936 return iph;
937
938 else if (iph->version == 6)
939 return skb_header_pointer(skb, offset, sizeof(struct ipv6hdr),
940 buf);
941
942 return NULL;
943}
944
945static struct tcphdr *cake_get_tcphdr(const struct sk_buff *skb,
946 void *buf, unsigned int bufsize)
947{
948 unsigned int offset = skb_network_offset(skb);
949 const struct ipv6hdr *ipv6h;
950 const struct tcphdr *tcph;
951 const struct iphdr *iph;
952 struct ipv6hdr _ipv6h;
953 struct tcphdr _tcph;
954
955 ipv6h = skb_header_pointer(skb, offset, sizeof(_ipv6h), &_ipv6h);
956
957 if (!ipv6h)
958 return NULL;
959
960 if (ipv6h->version == 4) {
961 iph = (struct iphdr *)ipv6h;
962 offset += iph->ihl * 4;
963
964 /* special-case 6in4 tunnelling, as that is a common way to get
965 * v6 connectivity in the home
966 */
967 if (iph->protocol == IPPROTO_IPV6) {
968 ipv6h = skb_header_pointer(skb, offset,
969 sizeof(_ipv6h), &_ipv6h);
970
971 if (!ipv6h || ipv6h->nexthdr != IPPROTO_TCP)
972 return NULL;
973
974 offset += sizeof(struct ipv6hdr);
975
976 } else if (iph->protocol != IPPROTO_TCP) {
977 return NULL;
978 }
979
980 } else if (ipv6h->version == 6) {
981 if (ipv6h->nexthdr != IPPROTO_TCP)
982 return NULL;
983
984 offset += sizeof(struct ipv6hdr);
985 } else {
986 return NULL;
987 }
988
989 tcph = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph);
990 if (!tcph || tcph->doff < 5)
991 return NULL;
992
993 return skb_header_pointer(skb, offset,
994 min(__tcp_hdrlen(tcph), bufsize), buf);
995}
996
997static const void *cake_get_tcpopt(const struct tcphdr *tcph,
998 int code, int *oplen)
999{
1000 /* inspired by tcp_parse_options in tcp_input.c */
1001 int length = __tcp_hdrlen(tcph) - sizeof(struct tcphdr);
1002 const u8 *ptr = (const u8 *)(tcph + 1);
1003
1004 while (length > 0) {
1005 int opcode = *ptr++;
1006 int opsize;
1007
1008 if (opcode == TCPOPT_EOL)
1009 break;
1010 if (opcode == TCPOPT_NOP) {
1011 length--;
1012 continue;
1013 }
1014 if (length < 2)
1015 break;
1016 opsize = *ptr++;
1017 if (opsize < 2 || opsize > length)
1018 break;
1019
1020 if (opcode == code) {
1021 *oplen = opsize;
1022 return ptr;
1023 }
1024
1025 ptr += opsize - 2;
1026 length -= opsize;
1027 }
1028
1029 return NULL;
1030}
1031
1032/* Compare two SACK sequences. A sequence is considered greater if it SACKs more
1033 * bytes than the other. In the case where both sequences ACKs bytes that the
1034 * other doesn't, A is considered greater. DSACKs in A also makes A be
1035 * considered greater.
1036 *
1037 * @return -1, 0 or 1 as normal compare functions
1038 */
1039static int cake_tcph_sack_compare(const struct tcphdr *tcph_a,
1040 const struct tcphdr *tcph_b)
1041{
1042 const struct tcp_sack_block_wire *sack_a, *sack_b;
1043 u32 ack_seq_a = ntohl(tcph_a->ack_seq);
1044 u32 bytes_a = 0, bytes_b = 0;
1045 int oplen_a, oplen_b;
1046 bool first = true;
1047
1048 sack_a = cake_get_tcpopt(tcph_a, TCPOPT_SACK, &oplen_a);
1049 sack_b = cake_get_tcpopt(tcph_b, TCPOPT_SACK, &oplen_b);
1050
1051 /* pointers point to option contents */
1052 oplen_a -= TCPOLEN_SACK_BASE;
1053 oplen_b -= TCPOLEN_SACK_BASE;
1054
1055 if (sack_a && oplen_a >= sizeof(*sack_a) &&
1056 (!sack_b || oplen_b < sizeof(*sack_b)))
1057 return -1;
1058 else if (sack_b && oplen_b >= sizeof(*sack_b) &&
1059 (!sack_a || oplen_a < sizeof(*sack_a)))
1060 return 1;
1061 else if ((!sack_a || oplen_a < sizeof(*sack_a)) &&
1062 (!sack_b || oplen_b < sizeof(*sack_b)))
1063 return 0;
1064
1065 while (oplen_a >= sizeof(*sack_a)) {
1066 const struct tcp_sack_block_wire *sack_tmp = sack_b;
1067 u32 start_a = get_unaligned_be32(&sack_a->start_seq);
1068 u32 end_a = get_unaligned_be32(&sack_a->end_seq);
1069 int oplen_tmp = oplen_b;
1070 bool found = false;
1071
1072 /* DSACK; always considered greater to prevent dropping */
1073 if (before(start_a, ack_seq_a))
1074 return -1;
1075
1076 bytes_a += end_a - start_a;
1077
1078 while (oplen_tmp >= sizeof(*sack_tmp)) {
1079 u32 start_b = get_unaligned_be32(&sack_tmp->start_seq);
1080 u32 end_b = get_unaligned_be32(&sack_tmp->end_seq);
1081
1082 /* first time through we count the total size */
1083 if (first)
1084 bytes_b += end_b - start_b;
1085
1086 if (!after(start_b, start_a) && !before(end_b, end_a)) {
1087 found = true;
1088 if (!first)
1089 break;
1090 }
1091 oplen_tmp -= sizeof(*sack_tmp);
1092 sack_tmp++;
1093 }
1094
1095 if (!found)
1096 return -1;
1097
1098 oplen_a -= sizeof(*sack_a);
1099 sack_a++;
1100 first = false;
1101 }
1102
1103 /* If we made it this far, all ranges SACKed by A are covered by B, so
1104 * either the SACKs are equal, or B SACKs more bytes.
1105 */
1106 return bytes_b > bytes_a ? 1 : 0;
1107}
1108
1109static void cake_tcph_get_tstamp(const struct tcphdr *tcph,
1110 u32 *tsval, u32 *tsecr)
1111{
1112 const u8 *ptr;
1113 int opsize;
1114
1115 ptr = cake_get_tcpopt(tcph, TCPOPT_TIMESTAMP, &opsize);
1116
1117 if (ptr && opsize == TCPOLEN_TIMESTAMP) {
1118 *tsval = get_unaligned_be32(ptr);
1119 *tsecr = get_unaligned_be32(ptr + 4);
1120 }
1121}
1122
1123static bool cake_tcph_may_drop(const struct tcphdr *tcph,
1124 u32 tstamp_new, u32 tsecr_new)
1125{
1126 /* inspired by tcp_parse_options in tcp_input.c */
1127 int length = __tcp_hdrlen(tcph) - sizeof(struct tcphdr);
1128 const u8 *ptr = (const u8 *)(tcph + 1);
1129 u32 tstamp, tsecr;
1130
1131 /* 3 reserved flags must be unset to avoid future breakage
1132 * ACK must be set
1133 * ECE/CWR are handled separately
1134 * All other flags URG/PSH/RST/SYN/FIN must be unset
1135 * 0x0FFF0000 = all TCP flags (confirm ACK=1, others zero)
1136 * 0x00C00000 = CWR/ECE (handled separately)
1137 * 0x0F3F0000 = 0x0FFF0000 & ~0x00C00000
1138 */
1139 if (((tcp_flag_word(tcph) &
1140 cpu_to_be32(0x0F3F0000)) != TCP_FLAG_ACK))
1141 return false;
1142
1143 while (length > 0) {
1144 int opcode = *ptr++;
1145 int opsize;
1146
1147 if (opcode == TCPOPT_EOL)
1148 break;
1149 if (opcode == TCPOPT_NOP) {
1150 length--;
1151 continue;
1152 }
1153 if (length < 2)
1154 break;
1155 opsize = *ptr++;
1156 if (opsize < 2 || opsize > length)
1157 break;
1158
1159 switch (opcode) {
1160 case TCPOPT_MD5SIG: /* doesn't influence state */
1161 break;
1162
1163 case TCPOPT_SACK: /* stricter checking performed later */
1164 if (opsize % 8 != 2)
1165 return false;
1166 break;
1167
1168 case TCPOPT_TIMESTAMP:
1169 /* only drop timestamps lower than new */
1170 if (opsize != TCPOLEN_TIMESTAMP)
1171 return false;
1172 tstamp = get_unaligned_be32(ptr);
1173 tsecr = get_unaligned_be32(ptr + 4);
1174 if (after(tstamp, tstamp_new) ||
1175 after(tsecr, tsecr_new))
1176 return false;
1177 break;
1178
1179 case TCPOPT_MSS: /* these should only be set on SYN */
1180 case TCPOPT_WINDOW:
1181 case TCPOPT_SACK_PERM:
1182 case TCPOPT_FASTOPEN:
1183 case TCPOPT_EXP:
1184 default: /* don't drop if any unknown options are present */
1185 return false;
1186 }
1187
1188 ptr += opsize - 2;
1189 length -= opsize;
1190 }
1191
1192 return true;
1193}
1194
1195static struct sk_buff *cake_ack_filter(struct cake_sched_data *q,
1196 struct cake_flow *flow)
1197{
1198 bool aggressive = q->ack_filter == CAKE_ACK_AGGRESSIVE;
1199 struct sk_buff *elig_ack = NULL, *elig_ack_prev = NULL;
1200 struct sk_buff *skb_check, *skb_prev = NULL;
1201 const struct ipv6hdr *ipv6h, *ipv6h_check;
1202 unsigned char _tcph[64], _tcph_check[64];
1203 const struct tcphdr *tcph, *tcph_check;
1204 const struct iphdr *iph, *iph_check;
1205 struct ipv6hdr _iph, _iph_check;
1206 const struct sk_buff *skb;
1207 int seglen, num_found = 0;
1208 u32 tstamp = 0, tsecr = 0;
1209 __be32 elig_flags = 0;
1210 int sack_comp;
1211
1212 /* no other possible ACKs to filter */
1213 if (flow->head == flow->tail)
1214 return NULL;
1215
1216 skb = flow->tail;
1217 tcph = cake_get_tcphdr(skb, _tcph, sizeof(_tcph));
1218 iph = cake_get_iphdr(skb, &_iph);
1219 if (!tcph)
1220 return NULL;
1221
1222 cake_tcph_get_tstamp(tcph, &tstamp, &tsecr);
1223
1224 /* the 'triggering' packet need only have the ACK flag set.
1225 * also check that SYN is not set, as there won't be any previous ACKs.
1226 */
1227 if ((tcp_flag_word(tcph) &
1228 (TCP_FLAG_ACK | TCP_FLAG_SYN)) != TCP_FLAG_ACK)
1229 return NULL;
1230
1231 /* the 'triggering' ACK is at the tail of the queue, we have already
1232 * returned if it is the only packet in the flow. loop through the rest
1233 * of the queue looking for pure ACKs with the same 5-tuple as the
1234 * triggering one.
1235 */
1236 for (skb_check = flow->head;
1237 skb_check && skb_check != skb;
1238 skb_prev = skb_check, skb_check = skb_check->next) {
1239 iph_check = cake_get_iphdr(skb_check, &_iph_check);
1240 tcph_check = cake_get_tcphdr(skb_check, &_tcph_check,
1241 sizeof(_tcph_check));
1242
1243 /* only TCP packets with matching 5-tuple are eligible, and only
1244 * drop safe headers
1245 */
1246 if (!tcph_check || iph->version != iph_check->version ||
1247 tcph_check->source != tcph->source ||
1248 tcph_check->dest != tcph->dest)
1249 continue;
1250
1251 if (iph_check->version == 4) {
1252 if (iph_check->saddr != iph->saddr ||
1253 iph_check->daddr != iph->daddr)
1254 continue;
1255
1256 seglen = iph_totlen(skb, iph_check) -
1257 (4 * iph_check->ihl);
1258 } else if (iph_check->version == 6) {
1259 ipv6h = (struct ipv6hdr *)iph;
1260 ipv6h_check = (struct ipv6hdr *)iph_check;
1261
1262 if (ipv6_addr_cmp(&ipv6h_check->saddr, &ipv6h->saddr) ||
1263 ipv6_addr_cmp(&ipv6h_check->daddr, &ipv6h->daddr))
1264 continue;
1265
1266 seglen = ntohs(ipv6h_check->payload_len);
1267 } else {
1268 WARN_ON(1); /* shouldn't happen */
1269 continue;
1270 }
1271
1272 /* If the ECE/CWR flags changed from the previous eligible
1273 * packet in the same flow, we should no longer be dropping that
1274 * previous packet as this would lose information.
1275 */
1276 if (elig_ack && (tcp_flag_word(tcph_check) &
1277 (TCP_FLAG_ECE | TCP_FLAG_CWR)) != elig_flags) {
1278 elig_ack = NULL;
1279 elig_ack_prev = NULL;
1280 num_found--;
1281 }
1282
1283 /* Check TCP options and flags, don't drop ACKs with segment
1284 * data, and don't drop ACKs with a higher cumulative ACK
1285 * counter than the triggering packet. Check ACK seqno here to
1286 * avoid parsing SACK options of packets we are going to exclude
1287 * anyway.
1288 */
1289 if (!cake_tcph_may_drop(tcph_check, tstamp, tsecr) ||
1290 (seglen - __tcp_hdrlen(tcph_check)) != 0 ||
1291 after(ntohl(tcph_check->ack_seq), ntohl(tcph->ack_seq)))
1292 continue;
1293
1294 /* Check SACK options. The triggering packet must SACK more data
1295 * than the ACK under consideration, or SACK the same range but
1296 * have a larger cumulative ACK counter. The latter is a
1297 * pathological case, but is contained in the following check
1298 * anyway, just to be safe.
1299 */
1300 sack_comp = cake_tcph_sack_compare(tcph_check, tcph);
1301
1302 if (sack_comp < 0 ||
1303 (ntohl(tcph_check->ack_seq) == ntohl(tcph->ack_seq) &&
1304 sack_comp == 0))
1305 continue;
1306
1307 /* At this point we have found an eligible pure ACK to drop; if
1308 * we are in aggressive mode, we are done. Otherwise, keep
1309 * searching unless this is the second eligible ACK we
1310 * found.
1311 *
1312 * Since we want to drop ACK closest to the head of the queue,
1313 * save the first eligible ACK we find, even if we need to loop
1314 * again.
1315 */
1316 if (!elig_ack) {
1317 elig_ack = skb_check;
1318 elig_ack_prev = skb_prev;
1319 elig_flags = (tcp_flag_word(tcph_check)
1320 & (TCP_FLAG_ECE | TCP_FLAG_CWR));
1321 }
1322
1323 if (num_found++ > 0)
1324 goto found;
1325 }
1326
1327 /* We made it through the queue without finding two eligible ACKs . If
1328 * we found a single eligible ACK we can drop it in aggressive mode if
1329 * we can guarantee that this does not interfere with ECN flag
1330 * information. We ensure this by dropping it only if the enqueued
1331 * packet is consecutive with the eligible ACK, and their flags match.
1332 */
1333 if (elig_ack && aggressive && elig_ack->next == skb &&
1334 (elig_flags == (tcp_flag_word(tcph) &
1335 (TCP_FLAG_ECE | TCP_FLAG_CWR))))
1336 goto found;
1337
1338 return NULL;
1339
1340found:
1341 if (elig_ack_prev)
1342 elig_ack_prev->next = elig_ack->next;
1343 else
1344 flow->head = elig_ack->next;
1345
1346 skb_mark_not_on_list(elig_ack);
1347
1348 return elig_ack;
1349}
1350
1351static u64 cake_ewma(u64 avg, u64 sample, u32 shift)
1352{
1353 avg -= avg >> shift;
1354 avg += sample >> shift;
1355 return avg;
1356}
1357
1358static u32 cake_calc_overhead(struct cake_sched_data *q, u32 len, u32 off)
1359{
1360 if (q->rate_flags & CAKE_FLAG_OVERHEAD)
1361 len -= off;
1362
1363 if (q->max_netlen < len)
1364 q->max_netlen = len;
1365 if (q->min_netlen > len)
1366 q->min_netlen = len;
1367
1368 len += q->rate_overhead;
1369
1370 if (len < q->rate_mpu)
1371 len = q->rate_mpu;
1372
1373 if (q->atm_mode == CAKE_ATM_ATM) {
1374 len += 47;
1375 len /= 48;
1376 len *= 53;
1377 } else if (q->atm_mode == CAKE_ATM_PTM) {
1378 /* Add one byte per 64 bytes or part thereof.
1379 * This is conservative and easier to calculate than the
1380 * precise value.
1381 */
1382 len += (len + 63) / 64;
1383 }
1384
1385 if (q->max_adjlen < len)
1386 q->max_adjlen = len;
1387 if (q->min_adjlen > len)
1388 q->min_adjlen = len;
1389
1390 return len;
1391}
1392
1393static u32 cake_overhead(struct cake_sched_data *q, const struct sk_buff *skb)
1394{
1395 const struct skb_shared_info *shinfo = skb_shinfo(skb);
1396 unsigned int hdr_len, last_len = 0;
1397 u32 off = skb_network_offset(skb);
1398 u32 len = qdisc_pkt_len(skb);
1399 u16 segs = 1;
1400
1401 q->avg_netoff = cake_ewma(q->avg_netoff, off << 16, 8);
1402
1403 if (!shinfo->gso_size)
1404 return cake_calc_overhead(q, len, off);
1405
1406 /* borrowed from qdisc_pkt_len_init() */
1407 hdr_len = skb_transport_offset(skb);
1408
1409 /* + transport layer */
1410 if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 |
1411 SKB_GSO_TCPV6))) {
1412 const struct tcphdr *th;
1413 struct tcphdr _tcphdr;
1414
1415 th = skb_header_pointer(skb, hdr_len,
1416 sizeof(_tcphdr), &_tcphdr);
1417 if (likely(th))
1418 hdr_len += __tcp_hdrlen(th);
1419 } else {
1420 struct udphdr _udphdr;
1421
1422 if (skb_header_pointer(skb, hdr_len,
1423 sizeof(_udphdr), &_udphdr))
1424 hdr_len += sizeof(struct udphdr);
1425 }
1426
1427 if (unlikely(shinfo->gso_type & SKB_GSO_DODGY))
1428 segs = DIV_ROUND_UP(skb->len - hdr_len,
1429 shinfo->gso_size);
1430 else
1431 segs = shinfo->gso_segs;
1432
1433 len = shinfo->gso_size + hdr_len;
1434 last_len = skb->len - shinfo->gso_size * (segs - 1);
1435
1436 return (cake_calc_overhead(q, len, off) * (segs - 1) +
1437 cake_calc_overhead(q, last_len, off));
1438}
1439
1440static void cake_heap_swap(struct cake_sched_data *q, u16 i, u16 j)
1441{
1442 struct cake_heap_entry ii = q->overflow_heap[i];
1443 struct cake_heap_entry jj = q->overflow_heap[j];
1444
1445 q->overflow_heap[i] = jj;
1446 q->overflow_heap[j] = ii;
1447
1448 q->tins[ii.t].overflow_idx[ii.b] = j;
1449 q->tins[jj.t].overflow_idx[jj.b] = i;
1450}
1451
1452static u32 cake_heap_get_backlog(const struct cake_sched_data *q, u16 i)
1453{
1454 struct cake_heap_entry ii = q->overflow_heap[i];
1455
1456 return q->tins[ii.t].backlogs[ii.b];
1457}
1458
1459static void cake_heapify(struct cake_sched_data *q, u16 i)
1460{
1461 static const u32 a = CAKE_MAX_TINS * CAKE_QUEUES;
1462 u32 mb = cake_heap_get_backlog(q, i);
1463 u32 m = i;
1464
1465 while (m < a) {
1466 u32 l = m + m + 1;
1467 u32 r = l + 1;
1468
1469 if (l < a) {
1470 u32 lb = cake_heap_get_backlog(q, l);
1471
1472 if (lb > mb) {
1473 m = l;
1474 mb = lb;
1475 }
1476 }
1477
1478 if (r < a) {
1479 u32 rb = cake_heap_get_backlog(q, r);
1480
1481 if (rb > mb) {
1482 m = r;
1483 mb = rb;
1484 }
1485 }
1486
1487 if (m != i) {
1488 cake_heap_swap(q, i, m);
1489 i = m;
1490 } else {
1491 break;
1492 }
1493 }
1494}
1495
1496static void cake_heapify_up(struct cake_sched_data *q, u16 i)
1497{
1498 while (i > 0 && i < CAKE_MAX_TINS * CAKE_QUEUES) {
1499 u16 p = (i - 1) >> 1;
1500 u32 ib = cake_heap_get_backlog(q, i);
1501 u32 pb = cake_heap_get_backlog(q, p);
1502
1503 if (ib > pb) {
1504 cake_heap_swap(q, i, p);
1505 i = p;
1506 } else {
1507 break;
1508 }
1509 }
1510}
1511
1512static int cake_advance_shaper(struct cake_sched_data *q,
1513 struct cake_tin_data *b,
1514 struct sk_buff *skb,
1515 ktime_t now, bool drop)
1516{
1517 u32 len = get_cobalt_cb(skb)->adjusted_len;
1518
1519 /* charge packet bandwidth to this tin
1520 * and to the global shaper.
1521 */
1522 if (q->rate_ns) {
1523 u64 tin_dur = (len * b->tin_rate_ns) >> b->tin_rate_shft;
1524 u64 global_dur = (len * q->rate_ns) >> q->rate_shft;
1525 u64 failsafe_dur = global_dur + (global_dur >> 1);
1526
1527 if (ktime_before(b->time_next_packet, now))
1528 b->time_next_packet = ktime_add_ns(b->time_next_packet,
1529 tin_dur);
1530
1531 else if (ktime_before(b->time_next_packet,
1532 ktime_add_ns(now, tin_dur)))
1533 b->time_next_packet = ktime_add_ns(now, tin_dur);
1534
1535 q->time_next_packet = ktime_add_ns(q->time_next_packet,
1536 global_dur);
1537 if (!drop)
1538 q->failsafe_next_packet = \
1539 ktime_add_ns(q->failsafe_next_packet,
1540 failsafe_dur);
1541 }
1542 return len;
1543}
1544
1545static unsigned int cake_drop(struct Qdisc *sch, struct sk_buff **to_free)
1546{
1547 struct cake_sched_data *q = qdisc_priv(sch);
1548 ktime_t now = ktime_get();
1549 u32 idx = 0, tin = 0, len;
1550 struct cake_heap_entry qq;
1551 struct cake_tin_data *b;
1552 struct cake_flow *flow;
1553 struct sk_buff *skb;
1554
1555 if (!q->overflow_timeout) {
1556 int i;
1557 /* Build fresh max-heap */
1558 for (i = CAKE_MAX_TINS * CAKE_QUEUES / 2 - 1; i >= 0; i--)
1559 cake_heapify(q, i);
1560 }
1561 q->overflow_timeout = 65535;
1562
1563 /* select longest queue for pruning */
1564 qq = q->overflow_heap[0];
1565 tin = qq.t;
1566 idx = qq.b;
1567
1568 b = &q->tins[tin];
1569 flow = &b->flows[idx];
1570 skb = dequeue_head(flow);
1571 if (unlikely(!skb)) {
1572 /* heap has gone wrong, rebuild it next time */
1573 q->overflow_timeout = 0;
1574 return idx + (tin << 16);
1575 }
1576
1577 if (cobalt_queue_full(&flow->cvars, &b->cparams, now))
1578 b->unresponsive_flow_count++;
1579
1580 len = qdisc_pkt_len(skb);
1581 q->buffer_used -= skb->truesize;
1582 b->backlogs[idx] -= len;
1583 b->tin_backlog -= len;
1584 sch->qstats.backlog -= len;
1585
1586 flow->dropped++;
1587 b->tin_dropped++;
1588 sch->qstats.drops++;
1589
1590 if (q->rate_flags & CAKE_FLAG_INGRESS)
1591 cake_advance_shaper(q, b, skb, now, true);
1592
1593 __qdisc_drop(skb, to_free);
1594 sch->q.qlen--;
1595 qdisc_tree_reduce_backlog(sch, 1, len);
1596
1597 cake_heapify(q, 0);
1598
1599 return idx + (tin << 16);
1600}
1601
1602static u8 cake_handle_diffserv(struct sk_buff *skb, bool wash)
1603{
1604 const int offset = skb_network_offset(skb);
1605 u16 *buf, buf_;
1606 u8 dscp;
1607
1608 switch (skb_protocol(skb, true)) {
1609 case htons(ETH_P_IP):
1610 buf = skb_header_pointer(skb, offset, sizeof(buf_), &buf_);
1611 if (unlikely(!buf))
1612 return 0;
1613
1614 /* ToS is in the second byte of iphdr */
1615 dscp = ipv4_get_dsfield((struct iphdr *)buf) >> 2;
1616
1617 if (wash && dscp) {
1618 const int wlen = offset + sizeof(struct iphdr);
1619
1620 if (!pskb_may_pull(skb, wlen) ||
1621 skb_try_make_writable(skb, wlen))
1622 return 0;
1623
1624 ipv4_change_dsfield(ip_hdr(skb), INET_ECN_MASK, 0);
1625 }
1626
1627 return dscp;
1628
1629 case htons(ETH_P_IPV6):
1630 buf = skb_header_pointer(skb, offset, sizeof(buf_), &buf_);
1631 if (unlikely(!buf))
1632 return 0;
1633
1634 /* Traffic class is in the first and second bytes of ipv6hdr */
1635 dscp = ipv6_get_dsfield((struct ipv6hdr *)buf) >> 2;
1636
1637 if (wash && dscp) {
1638 const int wlen = offset + sizeof(struct ipv6hdr);
1639
1640 if (!pskb_may_pull(skb, wlen) ||
1641 skb_try_make_writable(skb, wlen))
1642 return 0;
1643
1644 ipv6_change_dsfield(ipv6_hdr(skb), INET_ECN_MASK, 0);
1645 }
1646
1647 return dscp;
1648
1649 case htons(ETH_P_ARP):
1650 return 0x38; /* CS7 - Net Control */
1651
1652 default:
1653 /* If there is no Diffserv field, treat as best-effort */
1654 return 0;
1655 }
1656}
1657
1658static struct cake_tin_data *cake_select_tin(struct Qdisc *sch,
1659 struct sk_buff *skb)
1660{
1661 struct cake_sched_data *q = qdisc_priv(sch);
1662 u32 tin, mark;
1663 bool wash;
1664 u8 dscp;
1665
1666 /* Tin selection: Default to diffserv-based selection, allow overriding
1667 * using firewall marks or skb->priority. Call DSCP parsing early if
1668 * wash is enabled, otherwise defer to below to skip unneeded parsing.
1669 */
1670 mark = (skb->mark & q->fwmark_mask) >> q->fwmark_shft;
1671 wash = !!(q->rate_flags & CAKE_FLAG_WASH);
1672 if (wash)
1673 dscp = cake_handle_diffserv(skb, wash);
1674
1675 if (q->tin_mode == CAKE_DIFFSERV_BESTEFFORT)
1676 tin = 0;
1677
1678 else if (mark && mark <= q->tin_cnt)
1679 tin = q->tin_order[mark - 1];
1680
1681 else if (TC_H_MAJ(skb->priority) == sch->handle &&
1682 TC_H_MIN(skb->priority) > 0 &&
1683 TC_H_MIN(skb->priority) <= q->tin_cnt)
1684 tin = q->tin_order[TC_H_MIN(skb->priority) - 1];
1685
1686 else {
1687 if (!wash)
1688 dscp = cake_handle_diffserv(skb, wash);
1689 tin = q->tin_index[dscp];
1690
1691 if (unlikely(tin >= q->tin_cnt))
1692 tin = 0;
1693 }
1694
1695 return &q->tins[tin];
1696}
1697
1698static u32 cake_classify(struct Qdisc *sch, struct cake_tin_data **t,
1699 struct sk_buff *skb, int flow_mode, int *qerr)
1700{
1701 struct cake_sched_data *q = qdisc_priv(sch);
1702 struct tcf_proto *filter;
1703 struct tcf_result res;
1704 u16 flow = 0, host = 0;
1705 int result;
1706
1707 filter = rcu_dereference_bh(q->filter_list);
1708 if (!filter)
1709 goto hash;
1710
1711 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
1712 result = tcf_classify(skb, NULL, filter, &res, false);
1713
1714 if (result >= 0) {
1715#ifdef CONFIG_NET_CLS_ACT
1716 switch (result) {
1717 case TC_ACT_STOLEN:
1718 case TC_ACT_QUEUED:
1719 case TC_ACT_TRAP:
1720 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
1721 fallthrough;
1722 case TC_ACT_SHOT:
1723 return 0;
1724 }
1725#endif
1726 if (TC_H_MIN(res.classid) <= CAKE_QUEUES)
1727 flow = TC_H_MIN(res.classid);
1728 if (TC_H_MAJ(res.classid) <= (CAKE_QUEUES << 16))
1729 host = TC_H_MAJ(res.classid) >> 16;
1730 }
1731hash:
1732 *t = cake_select_tin(sch, skb);
1733 return cake_hash(*t, skb, flow_mode, flow, host) + 1;
1734}
1735
1736static void cake_reconfigure(struct Qdisc *sch);
1737
1738static s32 cake_enqueue(struct sk_buff *skb, struct Qdisc *sch,
1739 struct sk_buff **to_free)
1740{
1741 struct cake_sched_data *q = qdisc_priv(sch);
1742 int len = qdisc_pkt_len(skb);
1743 int ret;
1744 struct sk_buff *ack = NULL;
1745 ktime_t now = ktime_get();
1746 struct cake_tin_data *b;
1747 struct cake_flow *flow;
1748 u32 idx;
1749
1750 /* choose flow to insert into */
1751 idx = cake_classify(sch, &b, skb, q->flow_mode, &ret);
1752 if (idx == 0) {
1753 if (ret & __NET_XMIT_BYPASS)
1754 qdisc_qstats_drop(sch);
1755 __qdisc_drop(skb, to_free);
1756 return ret;
1757 }
1758 idx--;
1759 flow = &b->flows[idx];
1760
1761 /* ensure shaper state isn't stale */
1762 if (!b->tin_backlog) {
1763 if (ktime_before(b->time_next_packet, now))
1764 b->time_next_packet = now;
1765
1766 if (!sch->q.qlen) {
1767 if (ktime_before(q->time_next_packet, now)) {
1768 q->failsafe_next_packet = now;
1769 q->time_next_packet = now;
1770 } else if (ktime_after(q->time_next_packet, now) &&
1771 ktime_after(q->failsafe_next_packet, now)) {
1772 u64 next = \
1773 min(ktime_to_ns(q->time_next_packet),
1774 ktime_to_ns(
1775 q->failsafe_next_packet));
1776 sch->qstats.overlimits++;
1777 qdisc_watchdog_schedule_ns(&q->watchdog, next);
1778 }
1779 }
1780 }
1781
1782 if (unlikely(len > b->max_skblen))
1783 b->max_skblen = len;
1784
1785 if (skb_is_gso(skb) && q->rate_flags & CAKE_FLAG_SPLIT_GSO) {
1786 struct sk_buff *segs, *nskb;
1787 netdev_features_t features = netif_skb_features(skb);
1788 unsigned int slen = 0, numsegs = 0;
1789
1790 segs = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK);
1791 if (IS_ERR_OR_NULL(segs))
1792 return qdisc_drop(skb, sch, to_free);
1793
1794 skb_list_walk_safe(segs, segs, nskb) {
1795 skb_mark_not_on_list(segs);
1796 qdisc_skb_cb(segs)->pkt_len = segs->len;
1797 cobalt_set_enqueue_time(segs, now);
1798 get_cobalt_cb(segs)->adjusted_len = cake_overhead(q,
1799 segs);
1800 flow_queue_add(flow, segs);
1801
1802 sch->q.qlen++;
1803 numsegs++;
1804 slen += segs->len;
1805 q->buffer_used += segs->truesize;
1806 b->packets++;
1807 }
1808
1809 /* stats */
1810 b->bytes += slen;
1811 b->backlogs[idx] += slen;
1812 b->tin_backlog += slen;
1813 sch->qstats.backlog += slen;
1814 q->avg_window_bytes += slen;
1815
1816 qdisc_tree_reduce_backlog(sch, 1-numsegs, len-slen);
1817 consume_skb(skb);
1818 } else {
1819 /* not splitting */
1820 cobalt_set_enqueue_time(skb, now);
1821 get_cobalt_cb(skb)->adjusted_len = cake_overhead(q, skb);
1822 flow_queue_add(flow, skb);
1823
1824 if (q->ack_filter)
1825 ack = cake_ack_filter(q, flow);
1826
1827 if (ack) {
1828 b->ack_drops++;
1829 sch->qstats.drops++;
1830 b->bytes += qdisc_pkt_len(ack);
1831 len -= qdisc_pkt_len(ack);
1832 q->buffer_used += skb->truesize - ack->truesize;
1833 if (q->rate_flags & CAKE_FLAG_INGRESS)
1834 cake_advance_shaper(q, b, ack, now, true);
1835
1836 qdisc_tree_reduce_backlog(sch, 1, qdisc_pkt_len(ack));
1837 consume_skb(ack);
1838 } else {
1839 sch->q.qlen++;
1840 q->buffer_used += skb->truesize;
1841 }
1842
1843 /* stats */
1844 b->packets++;
1845 b->bytes += len;
1846 b->backlogs[idx] += len;
1847 b->tin_backlog += len;
1848 sch->qstats.backlog += len;
1849 q->avg_window_bytes += len;
1850 }
1851
1852 if (q->overflow_timeout)
1853 cake_heapify_up(q, b->overflow_idx[idx]);
1854
1855 /* incoming bandwidth capacity estimate */
1856 if (q->rate_flags & CAKE_FLAG_AUTORATE_INGRESS) {
1857 u64 packet_interval = \
1858 ktime_to_ns(ktime_sub(now, q->last_packet_time));
1859
1860 if (packet_interval > NSEC_PER_SEC)
1861 packet_interval = NSEC_PER_SEC;
1862
1863 /* filter out short-term bursts, eg. wifi aggregation */
1864 q->avg_packet_interval = \
1865 cake_ewma(q->avg_packet_interval,
1866 packet_interval,
1867 (packet_interval > q->avg_packet_interval ?
1868 2 : 8));
1869
1870 q->last_packet_time = now;
1871
1872 if (packet_interval > q->avg_packet_interval) {
1873 u64 window_interval = \
1874 ktime_to_ns(ktime_sub(now,
1875 q->avg_window_begin));
1876 u64 b = q->avg_window_bytes * (u64)NSEC_PER_SEC;
1877
1878 b = div64_u64(b, window_interval);
1879 q->avg_peak_bandwidth =
1880 cake_ewma(q->avg_peak_bandwidth, b,
1881 b > q->avg_peak_bandwidth ? 2 : 8);
1882 q->avg_window_bytes = 0;
1883 q->avg_window_begin = now;
1884
1885 if (ktime_after(now,
1886 ktime_add_ms(q->last_reconfig_time,
1887 250))) {
1888 q->rate_bps = (q->avg_peak_bandwidth * 15) >> 4;
1889 cake_reconfigure(sch);
1890 }
1891 }
1892 } else {
1893 q->avg_window_bytes = 0;
1894 q->last_packet_time = now;
1895 }
1896
1897 /* flowchain */
1898 if (!flow->set || flow->set == CAKE_SET_DECAYING) {
1899 if (!flow->set) {
1900 list_add_tail(&flow->flowchain, &b->new_flows);
1901 } else {
1902 b->decaying_flow_count--;
1903 list_move_tail(&flow->flowchain, &b->new_flows);
1904 }
1905 flow->set = CAKE_SET_SPARSE;
1906 b->sparse_flow_count++;
1907
1908 flow->deficit = cake_get_flow_quantum(b, flow, q->flow_mode);
1909 } else if (flow->set == CAKE_SET_SPARSE_WAIT) {
1910 /* this flow was empty, accounted as a sparse flow, but actually
1911 * in the bulk rotation.
1912 */
1913 flow->set = CAKE_SET_BULK;
1914 b->sparse_flow_count--;
1915 b->bulk_flow_count++;
1916
1917 cake_inc_srchost_bulk_flow_count(b, flow, q->flow_mode);
1918 cake_inc_dsthost_bulk_flow_count(b, flow, q->flow_mode);
1919 }
1920
1921 if (q->buffer_used > q->buffer_max_used)
1922 q->buffer_max_used = q->buffer_used;
1923
1924 if (q->buffer_used > q->buffer_limit) {
1925 u32 dropped = 0;
1926
1927 while (q->buffer_used > q->buffer_limit) {
1928 dropped++;
1929 cake_drop(sch, to_free);
1930 }
1931 b->drop_overlimit += dropped;
1932 }
1933 return NET_XMIT_SUCCESS;
1934}
1935
1936static struct sk_buff *cake_dequeue_one(struct Qdisc *sch)
1937{
1938 struct cake_sched_data *q = qdisc_priv(sch);
1939 struct cake_tin_data *b = &q->tins[q->cur_tin];
1940 struct cake_flow *flow = &b->flows[q->cur_flow];
1941 struct sk_buff *skb = NULL;
1942 u32 len;
1943
1944 if (flow->head) {
1945 skb = dequeue_head(flow);
1946 len = qdisc_pkt_len(skb);
1947 b->backlogs[q->cur_flow] -= len;
1948 b->tin_backlog -= len;
1949 sch->qstats.backlog -= len;
1950 q->buffer_used -= skb->truesize;
1951 sch->q.qlen--;
1952
1953 if (q->overflow_timeout)
1954 cake_heapify(q, b->overflow_idx[q->cur_flow]);
1955 }
1956 return skb;
1957}
1958
1959/* Discard leftover packets from a tin no longer in use. */
1960static void cake_clear_tin(struct Qdisc *sch, u16 tin)
1961{
1962 struct cake_sched_data *q = qdisc_priv(sch);
1963 struct sk_buff *skb;
1964
1965 q->cur_tin = tin;
1966 for (q->cur_flow = 0; q->cur_flow < CAKE_QUEUES; q->cur_flow++)
1967 while (!!(skb = cake_dequeue_one(sch)))
1968 kfree_skb(skb);
1969}
1970
1971static struct sk_buff *cake_dequeue(struct Qdisc *sch)
1972{
1973 struct cake_sched_data *q = qdisc_priv(sch);
1974 struct cake_tin_data *b = &q->tins[q->cur_tin];
1975 ktime_t now = ktime_get();
1976 struct cake_flow *flow;
1977 struct list_head *head;
1978 bool first_flow = true;
1979 struct sk_buff *skb;
1980 u64 delay;
1981 u32 len;
1982
1983begin:
1984 if (!sch->q.qlen)
1985 return NULL;
1986
1987 /* global hard shaper */
1988 if (ktime_after(q->time_next_packet, now) &&
1989 ktime_after(q->failsafe_next_packet, now)) {
1990 u64 next = min(ktime_to_ns(q->time_next_packet),
1991 ktime_to_ns(q->failsafe_next_packet));
1992
1993 sch->qstats.overlimits++;
1994 qdisc_watchdog_schedule_ns(&q->watchdog, next);
1995 return NULL;
1996 }
1997
1998 /* Choose a class to work on. */
1999 if (!q->rate_ns) {
2000 /* In unlimited mode, can't rely on shaper timings, just balance
2001 * with DRR
2002 */
2003 bool wrapped = false, empty = true;
2004
2005 while (b->tin_deficit < 0 ||
2006 !(b->sparse_flow_count + b->bulk_flow_count)) {
2007 if (b->tin_deficit <= 0)
2008 b->tin_deficit += b->tin_quantum;
2009 if (b->sparse_flow_count + b->bulk_flow_count)
2010 empty = false;
2011
2012 q->cur_tin++;
2013 b++;
2014 if (q->cur_tin >= q->tin_cnt) {
2015 q->cur_tin = 0;
2016 b = q->tins;
2017
2018 if (wrapped) {
2019 /* It's possible for q->qlen to be
2020 * nonzero when we actually have no
2021 * packets anywhere.
2022 */
2023 if (empty)
2024 return NULL;
2025 } else {
2026 wrapped = true;
2027 }
2028 }
2029 }
2030 } else {
2031 /* In shaped mode, choose:
2032 * - Highest-priority tin with queue and meeting schedule, or
2033 * - The earliest-scheduled tin with queue.
2034 */
2035 ktime_t best_time = KTIME_MAX;
2036 int tin, best_tin = 0;
2037
2038 for (tin = 0; tin < q->tin_cnt; tin++) {
2039 b = q->tins + tin;
2040 if ((b->sparse_flow_count + b->bulk_flow_count) > 0) {
2041 ktime_t time_to_pkt = \
2042 ktime_sub(b->time_next_packet, now);
2043
2044 if (ktime_to_ns(time_to_pkt) <= 0 ||
2045 ktime_compare(time_to_pkt,
2046 best_time) <= 0) {
2047 best_time = time_to_pkt;
2048 best_tin = tin;
2049 }
2050 }
2051 }
2052
2053 q->cur_tin = best_tin;
2054 b = q->tins + best_tin;
2055
2056 /* No point in going further if no packets to deliver. */
2057 if (unlikely(!(b->sparse_flow_count + b->bulk_flow_count)))
2058 return NULL;
2059 }
2060
2061retry:
2062 /* service this class */
2063 head = &b->decaying_flows;
2064 if (!first_flow || list_empty(head)) {
2065 head = &b->new_flows;
2066 if (list_empty(head)) {
2067 head = &b->old_flows;
2068 if (unlikely(list_empty(head))) {
2069 head = &b->decaying_flows;
2070 if (unlikely(list_empty(head)))
2071 goto begin;
2072 }
2073 }
2074 }
2075 flow = list_first_entry(head, struct cake_flow, flowchain);
2076 q->cur_flow = flow - b->flows;
2077 first_flow = false;
2078
2079 /* flow isolation (DRR++) */
2080 if (flow->deficit <= 0) {
2081 /* Keep all flows with deficits out of the sparse and decaying
2082 * rotations. No non-empty flow can go into the decaying
2083 * rotation, so they can't get deficits
2084 */
2085 if (flow->set == CAKE_SET_SPARSE) {
2086 if (flow->head) {
2087 b->sparse_flow_count--;
2088 b->bulk_flow_count++;
2089
2090 cake_inc_srchost_bulk_flow_count(b, flow, q->flow_mode);
2091 cake_inc_dsthost_bulk_flow_count(b, flow, q->flow_mode);
2092
2093 flow->set = CAKE_SET_BULK;
2094 } else {
2095 /* we've moved it to the bulk rotation for
2096 * correct deficit accounting but we still want
2097 * to count it as a sparse flow, not a bulk one.
2098 */
2099 flow->set = CAKE_SET_SPARSE_WAIT;
2100 }
2101 }
2102
2103 flow->deficit += cake_get_flow_quantum(b, flow, q->flow_mode);
2104 list_move_tail(&flow->flowchain, &b->old_flows);
2105
2106 goto retry;
2107 }
2108
2109 /* Retrieve a packet via the AQM */
2110 while (1) {
2111 skb = cake_dequeue_one(sch);
2112 if (!skb) {
2113 /* this queue was actually empty */
2114 if (cobalt_queue_empty(&flow->cvars, &b->cparams, now))
2115 b->unresponsive_flow_count--;
2116
2117 if (flow->cvars.p_drop || flow->cvars.count ||
2118 ktime_before(now, flow->cvars.drop_next)) {
2119 /* keep in the flowchain until the state has
2120 * decayed to rest
2121 */
2122 list_move_tail(&flow->flowchain,
2123 &b->decaying_flows);
2124 if (flow->set == CAKE_SET_BULK) {
2125 b->bulk_flow_count--;
2126
2127 cake_dec_srchost_bulk_flow_count(b, flow, q->flow_mode);
2128 cake_dec_dsthost_bulk_flow_count(b, flow, q->flow_mode);
2129
2130 b->decaying_flow_count++;
2131 } else if (flow->set == CAKE_SET_SPARSE ||
2132 flow->set == CAKE_SET_SPARSE_WAIT) {
2133 b->sparse_flow_count--;
2134 b->decaying_flow_count++;
2135 }
2136 flow->set = CAKE_SET_DECAYING;
2137 } else {
2138 /* remove empty queue from the flowchain */
2139 list_del_init(&flow->flowchain);
2140 if (flow->set == CAKE_SET_SPARSE ||
2141 flow->set == CAKE_SET_SPARSE_WAIT)
2142 b->sparse_flow_count--;
2143 else if (flow->set == CAKE_SET_BULK) {
2144 b->bulk_flow_count--;
2145
2146 cake_dec_srchost_bulk_flow_count(b, flow, q->flow_mode);
2147 cake_dec_dsthost_bulk_flow_count(b, flow, q->flow_mode);
2148 } else
2149 b->decaying_flow_count--;
2150
2151 flow->set = CAKE_SET_NONE;
2152 }
2153 goto begin;
2154 }
2155
2156 /* Last packet in queue may be marked, shouldn't be dropped */
2157 if (!cobalt_should_drop(&flow->cvars, &b->cparams, now, skb,
2158 (b->bulk_flow_count *
2159 !!(q->rate_flags &
2160 CAKE_FLAG_INGRESS))) ||
2161 !flow->head)
2162 break;
2163
2164 /* drop this packet, get another one */
2165 if (q->rate_flags & CAKE_FLAG_INGRESS) {
2166 len = cake_advance_shaper(q, b, skb,
2167 now, true);
2168 flow->deficit -= len;
2169 b->tin_deficit -= len;
2170 }
2171 flow->dropped++;
2172 b->tin_dropped++;
2173 qdisc_tree_reduce_backlog(sch, 1, qdisc_pkt_len(skb));
2174 qdisc_qstats_drop(sch);
2175 kfree_skb(skb);
2176 if (q->rate_flags & CAKE_FLAG_INGRESS)
2177 goto retry;
2178 }
2179
2180 b->tin_ecn_mark += !!flow->cvars.ecn_marked;
2181 qdisc_bstats_update(sch, skb);
2182
2183 /* collect delay stats */
2184 delay = ktime_to_ns(ktime_sub(now, cobalt_get_enqueue_time(skb)));
2185 b->avge_delay = cake_ewma(b->avge_delay, delay, 8);
2186 b->peak_delay = cake_ewma(b->peak_delay, delay,
2187 delay > b->peak_delay ? 2 : 8);
2188 b->base_delay = cake_ewma(b->base_delay, delay,
2189 delay < b->base_delay ? 2 : 8);
2190
2191 len = cake_advance_shaper(q, b, skb, now, false);
2192 flow->deficit -= len;
2193 b->tin_deficit -= len;
2194
2195 if (ktime_after(q->time_next_packet, now) && sch->q.qlen) {
2196 u64 next = min(ktime_to_ns(q->time_next_packet),
2197 ktime_to_ns(q->failsafe_next_packet));
2198
2199 qdisc_watchdog_schedule_ns(&q->watchdog, next);
2200 } else if (!sch->q.qlen) {
2201 int i;
2202
2203 for (i = 0; i < q->tin_cnt; i++) {
2204 if (q->tins[i].decaying_flow_count) {
2205 ktime_t next = \
2206 ktime_add_ns(now,
2207 q->tins[i].cparams.target);
2208
2209 qdisc_watchdog_schedule_ns(&q->watchdog,
2210 ktime_to_ns(next));
2211 break;
2212 }
2213 }
2214 }
2215
2216 if (q->overflow_timeout)
2217 q->overflow_timeout--;
2218
2219 return skb;
2220}
2221
2222static void cake_reset(struct Qdisc *sch)
2223{
2224 struct cake_sched_data *q = qdisc_priv(sch);
2225 u32 c;
2226
2227 if (!q->tins)
2228 return;
2229
2230 for (c = 0; c < CAKE_MAX_TINS; c++)
2231 cake_clear_tin(sch, c);
2232}
2233
2234static const struct nla_policy cake_policy[TCA_CAKE_MAX + 1] = {
2235 [TCA_CAKE_BASE_RATE64] = { .type = NLA_U64 },
2236 [TCA_CAKE_DIFFSERV_MODE] = { .type = NLA_U32 },
2237 [TCA_CAKE_ATM] = { .type = NLA_U32 },
2238 [TCA_CAKE_FLOW_MODE] = { .type = NLA_U32 },
2239 [TCA_CAKE_OVERHEAD] = { .type = NLA_S32 },
2240 [TCA_CAKE_RTT] = { .type = NLA_U32 },
2241 [TCA_CAKE_TARGET] = { .type = NLA_U32 },
2242 [TCA_CAKE_AUTORATE] = { .type = NLA_U32 },
2243 [TCA_CAKE_MEMORY] = { .type = NLA_U32 },
2244 [TCA_CAKE_NAT] = { .type = NLA_U32 },
2245 [TCA_CAKE_RAW] = { .type = NLA_U32 },
2246 [TCA_CAKE_WASH] = { .type = NLA_U32 },
2247 [TCA_CAKE_MPU] = { .type = NLA_U32 },
2248 [TCA_CAKE_INGRESS] = { .type = NLA_U32 },
2249 [TCA_CAKE_ACK_FILTER] = { .type = NLA_U32 },
2250 [TCA_CAKE_SPLIT_GSO] = { .type = NLA_U32 },
2251 [TCA_CAKE_FWMARK] = { .type = NLA_U32 },
2252};
2253
2254static void cake_set_rate(struct cake_tin_data *b, u64 rate, u32 mtu,
2255 u64 target_ns, u64 rtt_est_ns)
2256{
2257 /* convert byte-rate into time-per-byte
2258 * so it will always unwedge in reasonable time.
2259 */
2260 static const u64 MIN_RATE = 64;
2261 u32 byte_target = mtu;
2262 u64 byte_target_ns;
2263 u8 rate_shft = 0;
2264 u64 rate_ns = 0;
2265
2266 b->flow_quantum = 1514;
2267 if (rate) {
2268 b->flow_quantum = max(min(rate >> 12, 1514ULL), 300ULL);
2269 rate_shft = 34;
2270 rate_ns = ((u64)NSEC_PER_SEC) << rate_shft;
2271 rate_ns = div64_u64(rate_ns, max(MIN_RATE, rate));
2272 while (!!(rate_ns >> 34)) {
2273 rate_ns >>= 1;
2274 rate_shft--;
2275 }
2276 } /* else unlimited, ie. zero delay */
2277
2278 b->tin_rate_bps = rate;
2279 b->tin_rate_ns = rate_ns;
2280 b->tin_rate_shft = rate_shft;
2281
2282 byte_target_ns = (byte_target * rate_ns) >> rate_shft;
2283
2284 b->cparams.target = max((byte_target_ns * 3) / 2, target_ns);
2285 b->cparams.interval = max(rtt_est_ns +
2286 b->cparams.target - target_ns,
2287 b->cparams.target * 2);
2288 b->cparams.mtu_time = byte_target_ns;
2289 b->cparams.p_inc = 1 << 24; /* 1/256 */
2290 b->cparams.p_dec = 1 << 20; /* 1/4096 */
2291}
2292
2293static int cake_config_besteffort(struct Qdisc *sch)
2294{
2295 struct cake_sched_data *q = qdisc_priv(sch);
2296 struct cake_tin_data *b = &q->tins[0];
2297 u32 mtu = psched_mtu(qdisc_dev(sch));
2298 u64 rate = q->rate_bps;
2299
2300 q->tin_cnt = 1;
2301
2302 q->tin_index = besteffort;
2303 q->tin_order = normal_order;
2304
2305 cake_set_rate(b, rate, mtu,
2306 us_to_ns(q->target), us_to_ns(q->interval));
2307 b->tin_quantum = 65535;
2308
2309 return 0;
2310}
2311
2312static int cake_config_precedence(struct Qdisc *sch)
2313{
2314 /* convert high-level (user visible) parameters into internal format */
2315 struct cake_sched_data *q = qdisc_priv(sch);
2316 u32 mtu = psched_mtu(qdisc_dev(sch));
2317 u64 rate = q->rate_bps;
2318 u32 quantum = 256;
2319 u32 i;
2320
2321 q->tin_cnt = 8;
2322 q->tin_index = precedence;
2323 q->tin_order = normal_order;
2324
2325 for (i = 0; i < q->tin_cnt; i++) {
2326 struct cake_tin_data *b = &q->tins[i];
2327
2328 cake_set_rate(b, rate, mtu, us_to_ns(q->target),
2329 us_to_ns(q->interval));
2330
2331 b->tin_quantum = max_t(u16, 1U, quantum);
2332
2333 /* calculate next class's parameters */
2334 rate *= 7;
2335 rate >>= 3;
2336
2337 quantum *= 7;
2338 quantum >>= 3;
2339 }
2340
2341 return 0;
2342}
2343
2344/* List of known Diffserv codepoints:
2345 *
2346 * Default Forwarding (DF/CS0) - Best Effort
2347 * Max Throughput (TOS2)
2348 * Min Delay (TOS4)
2349 * LLT "La" (TOS5)
2350 * Assured Forwarding 1 (AF1x) - x3
2351 * Assured Forwarding 2 (AF2x) - x3
2352 * Assured Forwarding 3 (AF3x) - x3
2353 * Assured Forwarding 4 (AF4x) - x3
2354 * Precedence Class 1 (CS1)
2355 * Precedence Class 2 (CS2)
2356 * Precedence Class 3 (CS3)
2357 * Precedence Class 4 (CS4)
2358 * Precedence Class 5 (CS5)
2359 * Precedence Class 6 (CS6)
2360 * Precedence Class 7 (CS7)
2361 * Voice Admit (VA)
2362 * Expedited Forwarding (EF)
2363 * Lower Effort (LE)
2364 *
2365 * Total 26 codepoints.
2366 */
2367
2368/* List of traffic classes in RFC 4594, updated by RFC 8622:
2369 * (roughly descending order of contended priority)
2370 * (roughly ascending order of uncontended throughput)
2371 *
2372 * Network Control (CS6,CS7) - routing traffic
2373 * Telephony (EF,VA) - aka. VoIP streams
2374 * Signalling (CS5) - VoIP setup
2375 * Multimedia Conferencing (AF4x) - aka. video calls
2376 * Realtime Interactive (CS4) - eg. games
2377 * Multimedia Streaming (AF3x) - eg. YouTube, NetFlix, Twitch
2378 * Broadcast Video (CS3)
2379 * Low-Latency Data (AF2x,TOS4) - eg. database
2380 * Ops, Admin, Management (CS2) - eg. ssh
2381 * Standard Service (DF & unrecognised codepoints)
2382 * High-Throughput Data (AF1x,TOS2) - eg. web traffic
2383 * Low-Priority Data (LE,CS1) - eg. BitTorrent
2384 *
2385 * Total 12 traffic classes.
2386 */
2387
2388static int cake_config_diffserv8(struct Qdisc *sch)
2389{
2390/* Pruned list of traffic classes for typical applications:
2391 *
2392 * Network Control (CS6, CS7)
2393 * Minimum Latency (EF, VA, CS5, CS4)
2394 * Interactive Shell (CS2)
2395 * Low Latency Transactions (AF2x, TOS4)
2396 * Video Streaming (AF4x, AF3x, CS3)
2397 * Bog Standard (DF etc.)
2398 * High Throughput (AF1x, TOS2, CS1)
2399 * Background Traffic (LE)
2400 *
2401 * Total 8 traffic classes.
2402 */
2403
2404 struct cake_sched_data *q = qdisc_priv(sch);
2405 u32 mtu = psched_mtu(qdisc_dev(sch));
2406 u64 rate = q->rate_bps;
2407 u32 quantum = 256;
2408 u32 i;
2409
2410 q->tin_cnt = 8;
2411
2412 /* codepoint to class mapping */
2413 q->tin_index = diffserv8;
2414 q->tin_order = normal_order;
2415
2416 /* class characteristics */
2417 for (i = 0; i < q->tin_cnt; i++) {
2418 struct cake_tin_data *b = &q->tins[i];
2419
2420 cake_set_rate(b, rate, mtu, us_to_ns(q->target),
2421 us_to_ns(q->interval));
2422
2423 b->tin_quantum = max_t(u16, 1U, quantum);
2424
2425 /* calculate next class's parameters */
2426 rate *= 7;
2427 rate >>= 3;
2428
2429 quantum *= 7;
2430 quantum >>= 3;
2431 }
2432
2433 return 0;
2434}
2435
2436static int cake_config_diffserv4(struct Qdisc *sch)
2437{
2438/* Further pruned list of traffic classes for four-class system:
2439 *
2440 * Latency Sensitive (CS7, CS6, EF, VA, CS5, CS4)
2441 * Streaming Media (AF4x, AF3x, CS3, AF2x, TOS4, CS2)
2442 * Best Effort (DF, AF1x, TOS2, and those not specified)
2443 * Background Traffic (LE, CS1)
2444 *
2445 * Total 4 traffic classes.
2446 */
2447
2448 struct cake_sched_data *q = qdisc_priv(sch);
2449 u32 mtu = psched_mtu(qdisc_dev(sch));
2450 u64 rate = q->rate_bps;
2451 u32 quantum = 1024;
2452
2453 q->tin_cnt = 4;
2454
2455 /* codepoint to class mapping */
2456 q->tin_index = diffserv4;
2457 q->tin_order = bulk_order;
2458
2459 /* class characteristics */
2460 cake_set_rate(&q->tins[0], rate, mtu,
2461 us_to_ns(q->target), us_to_ns(q->interval));
2462 cake_set_rate(&q->tins[1], rate >> 4, mtu,
2463 us_to_ns(q->target), us_to_ns(q->interval));
2464 cake_set_rate(&q->tins[2], rate >> 1, mtu,
2465 us_to_ns(q->target), us_to_ns(q->interval));
2466 cake_set_rate(&q->tins[3], rate >> 2, mtu,
2467 us_to_ns(q->target), us_to_ns(q->interval));
2468
2469 /* bandwidth-sharing weights */
2470 q->tins[0].tin_quantum = quantum;
2471 q->tins[1].tin_quantum = quantum >> 4;
2472 q->tins[2].tin_quantum = quantum >> 1;
2473 q->tins[3].tin_quantum = quantum >> 2;
2474
2475 return 0;
2476}
2477
2478static int cake_config_diffserv3(struct Qdisc *sch)
2479{
2480/* Simplified Diffserv structure with 3 tins.
2481 * Latency Sensitive (CS7, CS6, EF, VA, TOS4)
2482 * Best Effort
2483 * Low Priority (LE, CS1)
2484 */
2485 struct cake_sched_data *q = qdisc_priv(sch);
2486 u32 mtu = psched_mtu(qdisc_dev(sch));
2487 u64 rate = q->rate_bps;
2488 u32 quantum = 1024;
2489
2490 q->tin_cnt = 3;
2491
2492 /* codepoint to class mapping */
2493 q->tin_index = diffserv3;
2494 q->tin_order = bulk_order;
2495
2496 /* class characteristics */
2497 cake_set_rate(&q->tins[0], rate, mtu,
2498 us_to_ns(q->target), us_to_ns(q->interval));
2499 cake_set_rate(&q->tins[1], rate >> 4, mtu,
2500 us_to_ns(q->target), us_to_ns(q->interval));
2501 cake_set_rate(&q->tins[2], rate >> 2, mtu,
2502 us_to_ns(q->target), us_to_ns(q->interval));
2503
2504 /* bandwidth-sharing weights */
2505 q->tins[0].tin_quantum = quantum;
2506 q->tins[1].tin_quantum = quantum >> 4;
2507 q->tins[2].tin_quantum = quantum >> 2;
2508
2509 return 0;
2510}
2511
2512static void cake_reconfigure(struct Qdisc *sch)
2513{
2514 struct cake_sched_data *q = qdisc_priv(sch);
2515 int c, ft;
2516
2517 switch (q->tin_mode) {
2518 case CAKE_DIFFSERV_BESTEFFORT:
2519 ft = cake_config_besteffort(sch);
2520 break;
2521
2522 case CAKE_DIFFSERV_PRECEDENCE:
2523 ft = cake_config_precedence(sch);
2524 break;
2525
2526 case CAKE_DIFFSERV_DIFFSERV8:
2527 ft = cake_config_diffserv8(sch);
2528 break;
2529
2530 case CAKE_DIFFSERV_DIFFSERV4:
2531 ft = cake_config_diffserv4(sch);
2532 break;
2533
2534 case CAKE_DIFFSERV_DIFFSERV3:
2535 default:
2536 ft = cake_config_diffserv3(sch);
2537 break;
2538 }
2539
2540 for (c = q->tin_cnt; c < CAKE_MAX_TINS; c++) {
2541 cake_clear_tin(sch, c);
2542 q->tins[c].cparams.mtu_time = q->tins[ft].cparams.mtu_time;
2543 }
2544
2545 q->rate_ns = q->tins[ft].tin_rate_ns;
2546 q->rate_shft = q->tins[ft].tin_rate_shft;
2547
2548 if (q->buffer_config_limit) {
2549 q->buffer_limit = q->buffer_config_limit;
2550 } else if (q->rate_bps) {
2551 u64 t = q->rate_bps * q->interval;
2552
2553 do_div(t, USEC_PER_SEC / 4);
2554 q->buffer_limit = max_t(u32, t, 4U << 20);
2555 } else {
2556 q->buffer_limit = ~0;
2557 }
2558
2559 sch->flags &= ~TCQ_F_CAN_BYPASS;
2560
2561 q->buffer_limit = min(q->buffer_limit,
2562 max(sch->limit * psched_mtu(qdisc_dev(sch)),
2563 q->buffer_config_limit));
2564}
2565
2566static int cake_change(struct Qdisc *sch, struct nlattr *opt,
2567 struct netlink_ext_ack *extack)
2568{
2569 struct cake_sched_data *q = qdisc_priv(sch);
2570 struct nlattr *tb[TCA_CAKE_MAX + 1];
2571 u16 rate_flags;
2572 u8 flow_mode;
2573 int err;
2574
2575 err = nla_parse_nested_deprecated(tb, TCA_CAKE_MAX, opt, cake_policy,
2576 extack);
2577 if (err < 0)
2578 return err;
2579
2580 flow_mode = q->flow_mode;
2581 if (tb[TCA_CAKE_NAT]) {
2582#if IS_ENABLED(CONFIG_NF_CONNTRACK)
2583 flow_mode &= ~CAKE_FLOW_NAT_FLAG;
2584 flow_mode |= CAKE_FLOW_NAT_FLAG *
2585 !!nla_get_u32(tb[TCA_CAKE_NAT]);
2586#else
2587 NL_SET_ERR_MSG_ATTR(extack, tb[TCA_CAKE_NAT],
2588 "No conntrack support in kernel");
2589 return -EOPNOTSUPP;
2590#endif
2591 }
2592
2593 if (tb[TCA_CAKE_BASE_RATE64])
2594 WRITE_ONCE(q->rate_bps,
2595 nla_get_u64(tb[TCA_CAKE_BASE_RATE64]));
2596
2597 if (tb[TCA_CAKE_DIFFSERV_MODE])
2598 WRITE_ONCE(q->tin_mode,
2599 nla_get_u32(tb[TCA_CAKE_DIFFSERV_MODE]));
2600
2601 rate_flags = q->rate_flags;
2602 if (tb[TCA_CAKE_WASH]) {
2603 if (!!nla_get_u32(tb[TCA_CAKE_WASH]))
2604 rate_flags |= CAKE_FLAG_WASH;
2605 else
2606 rate_flags &= ~CAKE_FLAG_WASH;
2607 }
2608
2609 if (tb[TCA_CAKE_FLOW_MODE])
2610 flow_mode = ((flow_mode & CAKE_FLOW_NAT_FLAG) |
2611 (nla_get_u32(tb[TCA_CAKE_FLOW_MODE]) &
2612 CAKE_FLOW_MASK));
2613
2614 if (tb[TCA_CAKE_ATM])
2615 WRITE_ONCE(q->atm_mode,
2616 nla_get_u32(tb[TCA_CAKE_ATM]));
2617
2618 if (tb[TCA_CAKE_OVERHEAD]) {
2619 WRITE_ONCE(q->rate_overhead,
2620 nla_get_s32(tb[TCA_CAKE_OVERHEAD]));
2621 rate_flags |= CAKE_FLAG_OVERHEAD;
2622
2623 q->max_netlen = 0;
2624 q->max_adjlen = 0;
2625 q->min_netlen = ~0;
2626 q->min_adjlen = ~0;
2627 }
2628
2629 if (tb[TCA_CAKE_RAW]) {
2630 rate_flags &= ~CAKE_FLAG_OVERHEAD;
2631
2632 q->max_netlen = 0;
2633 q->max_adjlen = 0;
2634 q->min_netlen = ~0;
2635 q->min_adjlen = ~0;
2636 }
2637
2638 if (tb[TCA_CAKE_MPU])
2639 WRITE_ONCE(q->rate_mpu,
2640 nla_get_u32(tb[TCA_CAKE_MPU]));
2641
2642 if (tb[TCA_CAKE_RTT]) {
2643 u32 interval = nla_get_u32(tb[TCA_CAKE_RTT]);
2644
2645 WRITE_ONCE(q->interval, max(interval, 1U));
2646 }
2647
2648 if (tb[TCA_CAKE_TARGET]) {
2649 u32 target = nla_get_u32(tb[TCA_CAKE_TARGET]);
2650
2651 WRITE_ONCE(q->target, max(target, 1U));
2652 }
2653
2654 if (tb[TCA_CAKE_AUTORATE]) {
2655 if (!!nla_get_u32(tb[TCA_CAKE_AUTORATE]))
2656 rate_flags |= CAKE_FLAG_AUTORATE_INGRESS;
2657 else
2658 rate_flags &= ~CAKE_FLAG_AUTORATE_INGRESS;
2659 }
2660
2661 if (tb[TCA_CAKE_INGRESS]) {
2662 if (!!nla_get_u32(tb[TCA_CAKE_INGRESS]))
2663 rate_flags |= CAKE_FLAG_INGRESS;
2664 else
2665 rate_flags &= ~CAKE_FLAG_INGRESS;
2666 }
2667
2668 if (tb[TCA_CAKE_ACK_FILTER])
2669 WRITE_ONCE(q->ack_filter,
2670 nla_get_u32(tb[TCA_CAKE_ACK_FILTER]));
2671
2672 if (tb[TCA_CAKE_MEMORY])
2673 WRITE_ONCE(q->buffer_config_limit,
2674 nla_get_u32(tb[TCA_CAKE_MEMORY]));
2675
2676 if (tb[TCA_CAKE_SPLIT_GSO]) {
2677 if (!!nla_get_u32(tb[TCA_CAKE_SPLIT_GSO]))
2678 rate_flags |= CAKE_FLAG_SPLIT_GSO;
2679 else
2680 rate_flags &= ~CAKE_FLAG_SPLIT_GSO;
2681 }
2682
2683 if (tb[TCA_CAKE_FWMARK]) {
2684 WRITE_ONCE(q->fwmark_mask, nla_get_u32(tb[TCA_CAKE_FWMARK]));
2685 WRITE_ONCE(q->fwmark_shft,
2686 q->fwmark_mask ? __ffs(q->fwmark_mask) : 0);
2687 }
2688
2689 WRITE_ONCE(q->rate_flags, rate_flags);
2690 WRITE_ONCE(q->flow_mode, flow_mode);
2691 if (q->tins) {
2692 sch_tree_lock(sch);
2693 cake_reconfigure(sch);
2694 sch_tree_unlock(sch);
2695 }
2696
2697 return 0;
2698}
2699
2700static void cake_destroy(struct Qdisc *sch)
2701{
2702 struct cake_sched_data *q = qdisc_priv(sch);
2703
2704 qdisc_watchdog_cancel(&q->watchdog);
2705 tcf_block_put(q->block);
2706 kvfree(q->tins);
2707}
2708
2709static int cake_init(struct Qdisc *sch, struct nlattr *opt,
2710 struct netlink_ext_ack *extack)
2711{
2712 struct cake_sched_data *q = qdisc_priv(sch);
2713 int i, j, err;
2714
2715 sch->limit = 10240;
2716 q->tin_mode = CAKE_DIFFSERV_DIFFSERV3;
2717 q->flow_mode = CAKE_FLOW_TRIPLE;
2718
2719 q->rate_bps = 0; /* unlimited by default */
2720
2721 q->interval = 100000; /* 100ms default */
2722 q->target = 5000; /* 5ms: codel RFC argues
2723 * for 5 to 10% of interval
2724 */
2725 q->rate_flags |= CAKE_FLAG_SPLIT_GSO;
2726 q->cur_tin = 0;
2727 q->cur_flow = 0;
2728
2729 qdisc_watchdog_init(&q->watchdog, sch);
2730
2731 if (opt) {
2732 err = cake_change(sch, opt, extack);
2733
2734 if (err)
2735 return err;
2736 }
2737
2738 err = tcf_block_get(&q->block, &q->filter_list, sch, extack);
2739 if (err)
2740 return err;
2741
2742 quantum_div[0] = ~0;
2743 for (i = 1; i <= CAKE_QUEUES; i++)
2744 quantum_div[i] = 65535 / i;
2745
2746 q->tins = kvcalloc(CAKE_MAX_TINS, sizeof(struct cake_tin_data),
2747 GFP_KERNEL);
2748 if (!q->tins)
2749 return -ENOMEM;
2750
2751 for (i = 0; i < CAKE_MAX_TINS; i++) {
2752 struct cake_tin_data *b = q->tins + i;
2753
2754 INIT_LIST_HEAD(&b->new_flows);
2755 INIT_LIST_HEAD(&b->old_flows);
2756 INIT_LIST_HEAD(&b->decaying_flows);
2757 b->sparse_flow_count = 0;
2758 b->bulk_flow_count = 0;
2759 b->decaying_flow_count = 0;
2760
2761 for (j = 0; j < CAKE_QUEUES; j++) {
2762 struct cake_flow *flow = b->flows + j;
2763 u32 k = j * CAKE_MAX_TINS + i;
2764
2765 INIT_LIST_HEAD(&flow->flowchain);
2766 cobalt_vars_init(&flow->cvars);
2767
2768 q->overflow_heap[k].t = i;
2769 q->overflow_heap[k].b = j;
2770 b->overflow_idx[j] = k;
2771 }
2772 }
2773
2774 cake_reconfigure(sch);
2775 q->avg_peak_bandwidth = q->rate_bps;
2776 q->min_netlen = ~0;
2777 q->min_adjlen = ~0;
2778 return 0;
2779}
2780
2781static int cake_dump(struct Qdisc *sch, struct sk_buff *skb)
2782{
2783 struct cake_sched_data *q = qdisc_priv(sch);
2784 struct nlattr *opts;
2785 u16 rate_flags;
2786 u8 flow_mode;
2787
2788 opts = nla_nest_start_noflag(skb, TCA_OPTIONS);
2789 if (!opts)
2790 goto nla_put_failure;
2791
2792 if (nla_put_u64_64bit(skb, TCA_CAKE_BASE_RATE64,
2793 READ_ONCE(q->rate_bps), TCA_CAKE_PAD))
2794 goto nla_put_failure;
2795
2796 flow_mode = READ_ONCE(q->flow_mode);
2797 if (nla_put_u32(skb, TCA_CAKE_FLOW_MODE, flow_mode & CAKE_FLOW_MASK))
2798 goto nla_put_failure;
2799
2800 if (nla_put_u32(skb, TCA_CAKE_RTT, READ_ONCE(q->interval)))
2801 goto nla_put_failure;
2802
2803 if (nla_put_u32(skb, TCA_CAKE_TARGET, READ_ONCE(q->target)))
2804 goto nla_put_failure;
2805
2806 if (nla_put_u32(skb, TCA_CAKE_MEMORY,
2807 READ_ONCE(q->buffer_config_limit)))
2808 goto nla_put_failure;
2809
2810 rate_flags = READ_ONCE(q->rate_flags);
2811 if (nla_put_u32(skb, TCA_CAKE_AUTORATE,
2812 !!(rate_flags & CAKE_FLAG_AUTORATE_INGRESS)))
2813 goto nla_put_failure;
2814
2815 if (nla_put_u32(skb, TCA_CAKE_INGRESS,
2816 !!(rate_flags & CAKE_FLAG_INGRESS)))
2817 goto nla_put_failure;
2818
2819 if (nla_put_u32(skb, TCA_CAKE_ACK_FILTER, READ_ONCE(q->ack_filter)))
2820 goto nla_put_failure;
2821
2822 if (nla_put_u32(skb, TCA_CAKE_NAT,
2823 !!(flow_mode & CAKE_FLOW_NAT_FLAG)))
2824 goto nla_put_failure;
2825
2826 if (nla_put_u32(skb, TCA_CAKE_DIFFSERV_MODE, READ_ONCE(q->tin_mode)))
2827 goto nla_put_failure;
2828
2829 if (nla_put_u32(skb, TCA_CAKE_WASH,
2830 !!(rate_flags & CAKE_FLAG_WASH)))
2831 goto nla_put_failure;
2832
2833 if (nla_put_u32(skb, TCA_CAKE_OVERHEAD, READ_ONCE(q->rate_overhead)))
2834 goto nla_put_failure;
2835
2836 if (!(rate_flags & CAKE_FLAG_OVERHEAD))
2837 if (nla_put_u32(skb, TCA_CAKE_RAW, 0))
2838 goto nla_put_failure;
2839
2840 if (nla_put_u32(skb, TCA_CAKE_ATM, READ_ONCE(q->atm_mode)))
2841 goto nla_put_failure;
2842
2843 if (nla_put_u32(skb, TCA_CAKE_MPU, READ_ONCE(q->rate_mpu)))
2844 goto nla_put_failure;
2845
2846 if (nla_put_u32(skb, TCA_CAKE_SPLIT_GSO,
2847 !!(rate_flags & CAKE_FLAG_SPLIT_GSO)))
2848 goto nla_put_failure;
2849
2850 if (nla_put_u32(skb, TCA_CAKE_FWMARK, READ_ONCE(q->fwmark_mask)))
2851 goto nla_put_failure;
2852
2853 return nla_nest_end(skb, opts);
2854
2855nla_put_failure:
2856 return -1;
2857}
2858
2859static int cake_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
2860{
2861 struct nlattr *stats = nla_nest_start_noflag(d->skb, TCA_STATS_APP);
2862 struct cake_sched_data *q = qdisc_priv(sch);
2863 struct nlattr *tstats, *ts;
2864 int i;
2865
2866 if (!stats)
2867 return -1;
2868
2869#define PUT_STAT_U32(attr, data) do { \
2870 if (nla_put_u32(d->skb, TCA_CAKE_STATS_ ## attr, data)) \
2871 goto nla_put_failure; \
2872 } while (0)
2873#define PUT_STAT_U64(attr, data) do { \
2874 if (nla_put_u64_64bit(d->skb, TCA_CAKE_STATS_ ## attr, \
2875 data, TCA_CAKE_STATS_PAD)) \
2876 goto nla_put_failure; \
2877 } while (0)
2878
2879 PUT_STAT_U64(CAPACITY_ESTIMATE64, q->avg_peak_bandwidth);
2880 PUT_STAT_U32(MEMORY_LIMIT, q->buffer_limit);
2881 PUT_STAT_U32(MEMORY_USED, q->buffer_max_used);
2882 PUT_STAT_U32(AVG_NETOFF, ((q->avg_netoff + 0x8000) >> 16));
2883 PUT_STAT_U32(MAX_NETLEN, q->max_netlen);
2884 PUT_STAT_U32(MAX_ADJLEN, q->max_adjlen);
2885 PUT_STAT_U32(MIN_NETLEN, q->min_netlen);
2886 PUT_STAT_U32(MIN_ADJLEN, q->min_adjlen);
2887
2888#undef PUT_STAT_U32
2889#undef PUT_STAT_U64
2890
2891 tstats = nla_nest_start_noflag(d->skb, TCA_CAKE_STATS_TIN_STATS);
2892 if (!tstats)
2893 goto nla_put_failure;
2894
2895#define PUT_TSTAT_U32(attr, data) do { \
2896 if (nla_put_u32(d->skb, TCA_CAKE_TIN_STATS_ ## attr, data)) \
2897 goto nla_put_failure; \
2898 } while (0)
2899#define PUT_TSTAT_U64(attr, data) do { \
2900 if (nla_put_u64_64bit(d->skb, TCA_CAKE_TIN_STATS_ ## attr, \
2901 data, TCA_CAKE_TIN_STATS_PAD)) \
2902 goto nla_put_failure; \
2903 } while (0)
2904
2905 for (i = 0; i < q->tin_cnt; i++) {
2906 struct cake_tin_data *b = &q->tins[q->tin_order[i]];
2907
2908 ts = nla_nest_start_noflag(d->skb, i + 1);
2909 if (!ts)
2910 goto nla_put_failure;
2911
2912 PUT_TSTAT_U64(THRESHOLD_RATE64, b->tin_rate_bps);
2913 PUT_TSTAT_U64(SENT_BYTES64, b->bytes);
2914 PUT_TSTAT_U32(BACKLOG_BYTES, b->tin_backlog);
2915
2916 PUT_TSTAT_U32(TARGET_US,
2917 ktime_to_us(ns_to_ktime(b->cparams.target)));
2918 PUT_TSTAT_U32(INTERVAL_US,
2919 ktime_to_us(ns_to_ktime(b->cparams.interval)));
2920
2921 PUT_TSTAT_U32(SENT_PACKETS, b->packets);
2922 PUT_TSTAT_U32(DROPPED_PACKETS, b->tin_dropped);
2923 PUT_TSTAT_U32(ECN_MARKED_PACKETS, b->tin_ecn_mark);
2924 PUT_TSTAT_U32(ACKS_DROPPED_PACKETS, b->ack_drops);
2925
2926 PUT_TSTAT_U32(PEAK_DELAY_US,
2927 ktime_to_us(ns_to_ktime(b->peak_delay)));
2928 PUT_TSTAT_U32(AVG_DELAY_US,
2929 ktime_to_us(ns_to_ktime(b->avge_delay)));
2930 PUT_TSTAT_U32(BASE_DELAY_US,
2931 ktime_to_us(ns_to_ktime(b->base_delay)));
2932
2933 PUT_TSTAT_U32(WAY_INDIRECT_HITS, b->way_hits);
2934 PUT_TSTAT_U32(WAY_MISSES, b->way_misses);
2935 PUT_TSTAT_U32(WAY_COLLISIONS, b->way_collisions);
2936
2937 PUT_TSTAT_U32(SPARSE_FLOWS, b->sparse_flow_count +
2938 b->decaying_flow_count);
2939 PUT_TSTAT_U32(BULK_FLOWS, b->bulk_flow_count);
2940 PUT_TSTAT_U32(UNRESPONSIVE_FLOWS, b->unresponsive_flow_count);
2941 PUT_TSTAT_U32(MAX_SKBLEN, b->max_skblen);
2942
2943 PUT_TSTAT_U32(FLOW_QUANTUM, b->flow_quantum);
2944 nla_nest_end(d->skb, ts);
2945 }
2946
2947#undef PUT_TSTAT_U32
2948#undef PUT_TSTAT_U64
2949
2950 nla_nest_end(d->skb, tstats);
2951 return nla_nest_end(d->skb, stats);
2952
2953nla_put_failure:
2954 nla_nest_cancel(d->skb, stats);
2955 return -1;
2956}
2957
2958static struct Qdisc *cake_leaf(struct Qdisc *sch, unsigned long arg)
2959{
2960 return NULL;
2961}
2962
2963static unsigned long cake_find(struct Qdisc *sch, u32 classid)
2964{
2965 return 0;
2966}
2967
2968static unsigned long cake_bind(struct Qdisc *sch, unsigned long parent,
2969 u32 classid)
2970{
2971 return 0;
2972}
2973
2974static void cake_unbind(struct Qdisc *q, unsigned long cl)
2975{
2976}
2977
2978static struct tcf_block *cake_tcf_block(struct Qdisc *sch, unsigned long cl,
2979 struct netlink_ext_ack *extack)
2980{
2981 struct cake_sched_data *q = qdisc_priv(sch);
2982
2983 if (cl)
2984 return NULL;
2985 return q->block;
2986}
2987
2988static int cake_dump_class(struct Qdisc *sch, unsigned long cl,
2989 struct sk_buff *skb, struct tcmsg *tcm)
2990{
2991 tcm->tcm_handle |= TC_H_MIN(cl);
2992 return 0;
2993}
2994
2995static int cake_dump_class_stats(struct Qdisc *sch, unsigned long cl,
2996 struct gnet_dump *d)
2997{
2998 struct cake_sched_data *q = qdisc_priv(sch);
2999 const struct cake_flow *flow = NULL;
3000 struct gnet_stats_queue qs = { 0 };
3001 struct nlattr *stats;
3002 u32 idx = cl - 1;
3003
3004 if (idx < CAKE_QUEUES * q->tin_cnt) {
3005 const struct cake_tin_data *b = \
3006 &q->tins[q->tin_order[idx / CAKE_QUEUES]];
3007 const struct sk_buff *skb;
3008
3009 flow = &b->flows[idx % CAKE_QUEUES];
3010
3011 if (flow->head) {
3012 sch_tree_lock(sch);
3013 skb = flow->head;
3014 while (skb) {
3015 qs.qlen++;
3016 skb = skb->next;
3017 }
3018 sch_tree_unlock(sch);
3019 }
3020 qs.backlog = b->backlogs[idx % CAKE_QUEUES];
3021 qs.drops = flow->dropped;
3022 }
3023 if (gnet_stats_copy_queue(d, NULL, &qs, qs.qlen) < 0)
3024 return -1;
3025 if (flow) {
3026 ktime_t now = ktime_get();
3027
3028 stats = nla_nest_start_noflag(d->skb, TCA_STATS_APP);
3029 if (!stats)
3030 return -1;
3031
3032#define PUT_STAT_U32(attr, data) do { \
3033 if (nla_put_u32(d->skb, TCA_CAKE_STATS_ ## attr, data)) \
3034 goto nla_put_failure; \
3035 } while (0)
3036#define PUT_STAT_S32(attr, data) do { \
3037 if (nla_put_s32(d->skb, TCA_CAKE_STATS_ ## attr, data)) \
3038 goto nla_put_failure; \
3039 } while (0)
3040
3041 PUT_STAT_S32(DEFICIT, flow->deficit);
3042 PUT_STAT_U32(DROPPING, flow->cvars.dropping);
3043 PUT_STAT_U32(COBALT_COUNT, flow->cvars.count);
3044 PUT_STAT_U32(P_DROP, flow->cvars.p_drop);
3045 if (flow->cvars.p_drop) {
3046 PUT_STAT_S32(BLUE_TIMER_US,
3047 ktime_to_us(
3048 ktime_sub(now,
3049 flow->cvars.blue_timer)));
3050 }
3051 if (flow->cvars.dropping) {
3052 PUT_STAT_S32(DROP_NEXT_US,
3053 ktime_to_us(
3054 ktime_sub(now,
3055 flow->cvars.drop_next)));
3056 }
3057
3058 if (nla_nest_end(d->skb, stats) < 0)
3059 return -1;
3060 }
3061
3062 return 0;
3063
3064nla_put_failure:
3065 nla_nest_cancel(d->skb, stats);
3066 return -1;
3067}
3068
3069static void cake_walk(struct Qdisc *sch, struct qdisc_walker *arg)
3070{
3071 struct cake_sched_data *q = qdisc_priv(sch);
3072 unsigned int i, j;
3073
3074 if (arg->stop)
3075 return;
3076
3077 for (i = 0; i < q->tin_cnt; i++) {
3078 struct cake_tin_data *b = &q->tins[q->tin_order[i]];
3079
3080 for (j = 0; j < CAKE_QUEUES; j++) {
3081 if (list_empty(&b->flows[j].flowchain)) {
3082 arg->count++;
3083 continue;
3084 }
3085 if (!tc_qdisc_stats_dump(sch, i * CAKE_QUEUES + j + 1,
3086 arg))
3087 break;
3088 }
3089 }
3090}
3091
3092static const struct Qdisc_class_ops cake_class_ops = {
3093 .leaf = cake_leaf,
3094 .find = cake_find,
3095 .tcf_block = cake_tcf_block,
3096 .bind_tcf = cake_bind,
3097 .unbind_tcf = cake_unbind,
3098 .dump = cake_dump_class,
3099 .dump_stats = cake_dump_class_stats,
3100 .walk = cake_walk,
3101};
3102
3103static struct Qdisc_ops cake_qdisc_ops __read_mostly = {
3104 .cl_ops = &cake_class_ops,
3105 .id = "cake",
3106 .priv_size = sizeof(struct cake_sched_data),
3107 .enqueue = cake_enqueue,
3108 .dequeue = cake_dequeue,
3109 .peek = qdisc_peek_dequeued,
3110 .init = cake_init,
3111 .reset = cake_reset,
3112 .destroy = cake_destroy,
3113 .change = cake_change,
3114 .dump = cake_dump,
3115 .dump_stats = cake_dump_stats,
3116 .owner = THIS_MODULE,
3117};
3118MODULE_ALIAS_NET_SCH("cake");
3119
3120static int __init cake_module_init(void)
3121{
3122 return register_qdisc(&cake_qdisc_ops);
3123}
3124
3125static void __exit cake_module_exit(void)
3126{
3127 unregister_qdisc(&cake_qdisc_ops);
3128}
3129
3130module_init(cake_module_init)
3131module_exit(cake_module_exit)
3132MODULE_AUTHOR("Jonathan Morton");
3133MODULE_LICENSE("Dual BSD/GPL");
3134MODULE_DESCRIPTION("The CAKE shaper.");
1// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
2
3/* COMMON Applications Kept Enhanced (CAKE) discipline
4 *
5 * Copyright (C) 2014-2018 Jonathan Morton <chromatix99@gmail.com>
6 * Copyright (C) 2015-2018 Toke Høiland-Jørgensen <toke@toke.dk>
7 * Copyright (C) 2014-2018 Dave Täht <dave.taht@gmail.com>
8 * Copyright (C) 2015-2018 Sebastian Moeller <moeller0@gmx.de>
9 * (C) 2015-2018 Kevin Darbyshire-Bryant <kevin@darbyshire-bryant.me.uk>
10 * Copyright (C) 2017-2018 Ryan Mounce <ryan@mounce.com.au>
11 *
12 * The CAKE Principles:
13 * (or, how to have your cake and eat it too)
14 *
15 * This is a combination of several shaping, AQM and FQ techniques into one
16 * easy-to-use package:
17 *
18 * - An overall bandwidth shaper, to move the bottleneck away from dumb CPE
19 * equipment and bloated MACs. This operates in deficit mode (as in sch_fq),
20 * eliminating the need for any sort of burst parameter (eg. token bucket
21 * depth). Burst support is limited to that necessary to overcome scheduling
22 * latency.
23 *
24 * - A Diffserv-aware priority queue, giving more priority to certain classes,
25 * up to a specified fraction of bandwidth. Above that bandwidth threshold,
26 * the priority is reduced to avoid starving other tins.
27 *
28 * - Each priority tin has a separate Flow Queue system, to isolate traffic
29 * flows from each other. This prevents a burst on one flow from increasing
30 * the delay to another. Flows are distributed to queues using a
31 * set-associative hash function.
32 *
33 * - Each queue is actively managed by Cobalt, which is a combination of the
34 * Codel and Blue AQM algorithms. This serves flows fairly, and signals
35 * congestion early via ECN (if available) and/or packet drops, to keep
36 * latency low. The codel parameters are auto-tuned based on the bandwidth
37 * setting, as is necessary at low bandwidths.
38 *
39 * The configuration parameters are kept deliberately simple for ease of use.
40 * Everything has sane defaults. Complete generality of configuration is *not*
41 * a goal.
42 *
43 * The priority queue operates according to a weighted DRR scheme, combined with
44 * a bandwidth tracker which reuses the shaper logic to detect which side of the
45 * bandwidth sharing threshold the tin is operating. This determines whether a
46 * priority-based weight (high) or a bandwidth-based weight (low) is used for
47 * that tin in the current pass.
48 *
49 * This qdisc was inspired by Eric Dumazet's fq_codel code, which he kindly
50 * granted us permission to leverage.
51 */
52
53#include <linux/module.h>
54#include <linux/types.h>
55#include <linux/kernel.h>
56#include <linux/jiffies.h>
57#include <linux/string.h>
58#include <linux/in.h>
59#include <linux/errno.h>
60#include <linux/init.h>
61#include <linux/skbuff.h>
62#include <linux/jhash.h>
63#include <linux/slab.h>
64#include <linux/vmalloc.h>
65#include <linux/reciprocal_div.h>
66#include <net/netlink.h>
67#include <linux/if_vlan.h>
68#include <net/pkt_sched.h>
69#include <net/pkt_cls.h>
70#include <net/tcp.h>
71#include <net/flow_dissector.h>
72
73#if IS_ENABLED(CONFIG_NF_CONNTRACK)
74#include <net/netfilter/nf_conntrack_core.h>
75#endif
76
77#define CAKE_SET_WAYS (8)
78#define CAKE_MAX_TINS (8)
79#define CAKE_QUEUES (1024)
80#define CAKE_FLOW_MASK 63
81#define CAKE_FLOW_NAT_FLAG 64
82
83/* struct cobalt_params - contains codel and blue parameters
84 * @interval: codel initial drop rate
85 * @target: maximum persistent sojourn time & blue update rate
86 * @mtu_time: serialisation delay of maximum-size packet
87 * @p_inc: increment of blue drop probability (0.32 fxp)
88 * @p_dec: decrement of blue drop probability (0.32 fxp)
89 */
90struct cobalt_params {
91 u64 interval;
92 u64 target;
93 u64 mtu_time;
94 u32 p_inc;
95 u32 p_dec;
96};
97
98/* struct cobalt_vars - contains codel and blue variables
99 * @count: codel dropping frequency
100 * @rec_inv_sqrt: reciprocal value of sqrt(count) >> 1
101 * @drop_next: time to drop next packet, or when we dropped last
102 * @blue_timer: Blue time to next drop
103 * @p_drop: BLUE drop probability (0.32 fxp)
104 * @dropping: set if in dropping state
105 * @ecn_marked: set if marked
106 */
107struct cobalt_vars {
108 u32 count;
109 u32 rec_inv_sqrt;
110 ktime_t drop_next;
111 ktime_t blue_timer;
112 u32 p_drop;
113 bool dropping;
114 bool ecn_marked;
115};
116
117enum {
118 CAKE_SET_NONE = 0,
119 CAKE_SET_SPARSE,
120 CAKE_SET_SPARSE_WAIT, /* counted in SPARSE, actually in BULK */
121 CAKE_SET_BULK,
122 CAKE_SET_DECAYING
123};
124
125struct cake_flow {
126 /* this stuff is all needed per-flow at dequeue time */
127 struct sk_buff *head;
128 struct sk_buff *tail;
129 struct list_head flowchain;
130 s32 deficit;
131 u32 dropped;
132 struct cobalt_vars cvars;
133 u16 srchost; /* index into cake_host table */
134 u16 dsthost;
135 u8 set;
136}; /* please try to keep this structure <= 64 bytes */
137
138struct cake_host {
139 u32 srchost_tag;
140 u32 dsthost_tag;
141 u16 srchost_bulk_flow_count;
142 u16 dsthost_bulk_flow_count;
143};
144
145struct cake_heap_entry {
146 u16 t:3, b:10;
147};
148
149struct cake_tin_data {
150 struct cake_flow flows[CAKE_QUEUES];
151 u32 backlogs[CAKE_QUEUES];
152 u32 tags[CAKE_QUEUES]; /* for set association */
153 u16 overflow_idx[CAKE_QUEUES];
154 struct cake_host hosts[CAKE_QUEUES]; /* for triple isolation */
155 u16 flow_quantum;
156
157 struct cobalt_params cparams;
158 u32 drop_overlimit;
159 u16 bulk_flow_count;
160 u16 sparse_flow_count;
161 u16 decaying_flow_count;
162 u16 unresponsive_flow_count;
163
164 u32 max_skblen;
165
166 struct list_head new_flows;
167 struct list_head old_flows;
168 struct list_head decaying_flows;
169
170 /* time_next = time_this + ((len * rate_ns) >> rate_shft) */
171 ktime_t time_next_packet;
172 u64 tin_rate_ns;
173 u64 tin_rate_bps;
174 u16 tin_rate_shft;
175
176 u16 tin_quantum_prio;
177 u16 tin_quantum_band;
178 s32 tin_deficit;
179 u32 tin_backlog;
180 u32 tin_dropped;
181 u32 tin_ecn_mark;
182
183 u32 packets;
184 u64 bytes;
185
186 u32 ack_drops;
187
188 /* moving averages */
189 u64 avge_delay;
190 u64 peak_delay;
191 u64 base_delay;
192
193 /* hash function stats */
194 u32 way_directs;
195 u32 way_hits;
196 u32 way_misses;
197 u32 way_collisions;
198}; /* number of tins is small, so size of this struct doesn't matter much */
199
200struct cake_sched_data {
201 struct tcf_proto __rcu *filter_list; /* optional external classifier */
202 struct tcf_block *block;
203 struct cake_tin_data *tins;
204
205 struct cake_heap_entry overflow_heap[CAKE_QUEUES * CAKE_MAX_TINS];
206 u16 overflow_timeout;
207
208 u16 tin_cnt;
209 u8 tin_mode;
210 u8 flow_mode;
211 u8 ack_filter;
212 u8 atm_mode;
213
214 u32 fwmark_mask;
215 u16 fwmark_shft;
216
217 /* time_next = time_this + ((len * rate_ns) >> rate_shft) */
218 u16 rate_shft;
219 ktime_t time_next_packet;
220 ktime_t failsafe_next_packet;
221 u64 rate_ns;
222 u64 rate_bps;
223 u16 rate_flags;
224 s16 rate_overhead;
225 u16 rate_mpu;
226 u64 interval;
227 u64 target;
228
229 /* resource tracking */
230 u32 buffer_used;
231 u32 buffer_max_used;
232 u32 buffer_limit;
233 u32 buffer_config_limit;
234
235 /* indices for dequeue */
236 u16 cur_tin;
237 u16 cur_flow;
238
239 struct qdisc_watchdog watchdog;
240 const u8 *tin_index;
241 const u8 *tin_order;
242
243 /* bandwidth capacity estimate */
244 ktime_t last_packet_time;
245 ktime_t avg_window_begin;
246 u64 avg_packet_interval;
247 u64 avg_window_bytes;
248 u64 avg_peak_bandwidth;
249 ktime_t last_reconfig_time;
250
251 /* packet length stats */
252 u32 avg_netoff;
253 u16 max_netlen;
254 u16 max_adjlen;
255 u16 min_netlen;
256 u16 min_adjlen;
257};
258
259enum {
260 CAKE_FLAG_OVERHEAD = BIT(0),
261 CAKE_FLAG_AUTORATE_INGRESS = BIT(1),
262 CAKE_FLAG_INGRESS = BIT(2),
263 CAKE_FLAG_WASH = BIT(3),
264 CAKE_FLAG_SPLIT_GSO = BIT(4)
265};
266
267/* COBALT operates the Codel and BLUE algorithms in parallel, in order to
268 * obtain the best features of each. Codel is excellent on flows which
269 * respond to congestion signals in a TCP-like way. BLUE is more effective on
270 * unresponsive flows.
271 */
272
273struct cobalt_skb_cb {
274 ktime_t enqueue_time;
275 u32 adjusted_len;
276};
277
278static u64 us_to_ns(u64 us)
279{
280 return us * NSEC_PER_USEC;
281}
282
283static struct cobalt_skb_cb *get_cobalt_cb(const struct sk_buff *skb)
284{
285 qdisc_cb_private_validate(skb, sizeof(struct cobalt_skb_cb));
286 return (struct cobalt_skb_cb *)qdisc_skb_cb(skb)->data;
287}
288
289static ktime_t cobalt_get_enqueue_time(const struct sk_buff *skb)
290{
291 return get_cobalt_cb(skb)->enqueue_time;
292}
293
294static void cobalt_set_enqueue_time(struct sk_buff *skb,
295 ktime_t now)
296{
297 get_cobalt_cb(skb)->enqueue_time = now;
298}
299
300static u16 quantum_div[CAKE_QUEUES + 1] = {0};
301
302/* Diffserv lookup tables */
303
304static const u8 precedence[] = {
305 0, 0, 0, 0, 0, 0, 0, 0,
306 1, 1, 1, 1, 1, 1, 1, 1,
307 2, 2, 2, 2, 2, 2, 2, 2,
308 3, 3, 3, 3, 3, 3, 3, 3,
309 4, 4, 4, 4, 4, 4, 4, 4,
310 5, 5, 5, 5, 5, 5, 5, 5,
311 6, 6, 6, 6, 6, 6, 6, 6,
312 7, 7, 7, 7, 7, 7, 7, 7,
313};
314
315static const u8 diffserv8[] = {
316 2, 5, 1, 2, 4, 2, 2, 2,
317 0, 2, 1, 2, 1, 2, 1, 2,
318 5, 2, 4, 2, 4, 2, 4, 2,
319 3, 2, 3, 2, 3, 2, 3, 2,
320 6, 2, 3, 2, 3, 2, 3, 2,
321 6, 2, 2, 2, 6, 2, 6, 2,
322 7, 2, 2, 2, 2, 2, 2, 2,
323 7, 2, 2, 2, 2, 2, 2, 2,
324};
325
326static const u8 diffserv4[] = {
327 0, 2, 0, 0, 2, 0, 0, 0,
328 1, 0, 0, 0, 0, 0, 0, 0,
329 2, 0, 2, 0, 2, 0, 2, 0,
330 2, 0, 2, 0, 2, 0, 2, 0,
331 3, 0, 2, 0, 2, 0, 2, 0,
332 3, 0, 0, 0, 3, 0, 3, 0,
333 3, 0, 0, 0, 0, 0, 0, 0,
334 3, 0, 0, 0, 0, 0, 0, 0,
335};
336
337static const u8 diffserv3[] = {
338 0, 0, 0, 0, 2, 0, 0, 0,
339 1, 0, 0, 0, 0, 0, 0, 0,
340 0, 0, 0, 0, 0, 0, 0, 0,
341 0, 0, 0, 0, 0, 0, 0, 0,
342 0, 0, 0, 0, 0, 0, 0, 0,
343 0, 0, 0, 0, 2, 0, 2, 0,
344 2, 0, 0, 0, 0, 0, 0, 0,
345 2, 0, 0, 0, 0, 0, 0, 0,
346};
347
348static const u8 besteffort[] = {
349 0, 0, 0, 0, 0, 0, 0, 0,
350 0, 0, 0, 0, 0, 0, 0, 0,
351 0, 0, 0, 0, 0, 0, 0, 0,
352 0, 0, 0, 0, 0, 0, 0, 0,
353 0, 0, 0, 0, 0, 0, 0, 0,
354 0, 0, 0, 0, 0, 0, 0, 0,
355 0, 0, 0, 0, 0, 0, 0, 0,
356 0, 0, 0, 0, 0, 0, 0, 0,
357};
358
359/* tin priority order for stats dumping */
360
361static const u8 normal_order[] = {0, 1, 2, 3, 4, 5, 6, 7};
362static const u8 bulk_order[] = {1, 0, 2, 3};
363
364#define REC_INV_SQRT_CACHE (16)
365static u32 cobalt_rec_inv_sqrt_cache[REC_INV_SQRT_CACHE] = {0};
366
367/* http://en.wikipedia.org/wiki/Methods_of_computing_square_roots
368 * new_invsqrt = (invsqrt / 2) * (3 - count * invsqrt^2)
369 *
370 * Here, invsqrt is a fixed point number (< 1.0), 32bit mantissa, aka Q0.32
371 */
372
373static void cobalt_newton_step(struct cobalt_vars *vars)
374{
375 u32 invsqrt, invsqrt2;
376 u64 val;
377
378 invsqrt = vars->rec_inv_sqrt;
379 invsqrt2 = ((u64)invsqrt * invsqrt) >> 32;
380 val = (3LL << 32) - ((u64)vars->count * invsqrt2);
381
382 val >>= 2; /* avoid overflow in following multiply */
383 val = (val * invsqrt) >> (32 - 2 + 1);
384
385 vars->rec_inv_sqrt = val;
386}
387
388static void cobalt_invsqrt(struct cobalt_vars *vars)
389{
390 if (vars->count < REC_INV_SQRT_CACHE)
391 vars->rec_inv_sqrt = cobalt_rec_inv_sqrt_cache[vars->count];
392 else
393 cobalt_newton_step(vars);
394}
395
396/* There is a big difference in timing between the accurate values placed in
397 * the cache and the approximations given by a single Newton step for small
398 * count values, particularly when stepping from count 1 to 2 or vice versa.
399 * Above 16, a single Newton step gives sufficient accuracy in either
400 * direction, given the precision stored.
401 *
402 * The magnitude of the error when stepping up to count 2 is such as to give
403 * the value that *should* have been produced at count 4.
404 */
405
406static void cobalt_cache_init(void)
407{
408 struct cobalt_vars v;
409
410 memset(&v, 0, sizeof(v));
411 v.rec_inv_sqrt = ~0U;
412 cobalt_rec_inv_sqrt_cache[0] = v.rec_inv_sqrt;
413
414 for (v.count = 1; v.count < REC_INV_SQRT_CACHE; v.count++) {
415 cobalt_newton_step(&v);
416 cobalt_newton_step(&v);
417 cobalt_newton_step(&v);
418 cobalt_newton_step(&v);
419
420 cobalt_rec_inv_sqrt_cache[v.count] = v.rec_inv_sqrt;
421 }
422}
423
424static void cobalt_vars_init(struct cobalt_vars *vars)
425{
426 memset(vars, 0, sizeof(*vars));
427
428 if (!cobalt_rec_inv_sqrt_cache[0]) {
429 cobalt_cache_init();
430 cobalt_rec_inv_sqrt_cache[0] = ~0;
431 }
432}
433
434/* CoDel control_law is t + interval/sqrt(count)
435 * We maintain in rec_inv_sqrt the reciprocal value of sqrt(count) to avoid
436 * both sqrt() and divide operation.
437 */
438static ktime_t cobalt_control(ktime_t t,
439 u64 interval,
440 u32 rec_inv_sqrt)
441{
442 return ktime_add_ns(t, reciprocal_scale(interval,
443 rec_inv_sqrt));
444}
445
446/* Call this when a packet had to be dropped due to queue overflow. Returns
447 * true if the BLUE state was quiescent before but active after this call.
448 */
449static bool cobalt_queue_full(struct cobalt_vars *vars,
450 struct cobalt_params *p,
451 ktime_t now)
452{
453 bool up = false;
454
455 if (ktime_to_ns(ktime_sub(now, vars->blue_timer)) > p->target) {
456 up = !vars->p_drop;
457 vars->p_drop += p->p_inc;
458 if (vars->p_drop < p->p_inc)
459 vars->p_drop = ~0;
460 vars->blue_timer = now;
461 }
462 vars->dropping = true;
463 vars->drop_next = now;
464 if (!vars->count)
465 vars->count = 1;
466
467 return up;
468}
469
470/* Call this when the queue was serviced but turned out to be empty. Returns
471 * true if the BLUE state was active before but quiescent after this call.
472 */
473static bool cobalt_queue_empty(struct cobalt_vars *vars,
474 struct cobalt_params *p,
475 ktime_t now)
476{
477 bool down = false;
478
479 if (vars->p_drop &&
480 ktime_to_ns(ktime_sub(now, vars->blue_timer)) > p->target) {
481 if (vars->p_drop < p->p_dec)
482 vars->p_drop = 0;
483 else
484 vars->p_drop -= p->p_dec;
485 vars->blue_timer = now;
486 down = !vars->p_drop;
487 }
488 vars->dropping = false;
489
490 if (vars->count && ktime_to_ns(ktime_sub(now, vars->drop_next)) >= 0) {
491 vars->count--;
492 cobalt_invsqrt(vars);
493 vars->drop_next = cobalt_control(vars->drop_next,
494 p->interval,
495 vars->rec_inv_sqrt);
496 }
497
498 return down;
499}
500
501/* Call this with a freshly dequeued packet for possible congestion marking.
502 * Returns true as an instruction to drop the packet, false for delivery.
503 */
504static bool cobalt_should_drop(struct cobalt_vars *vars,
505 struct cobalt_params *p,
506 ktime_t now,
507 struct sk_buff *skb,
508 u32 bulk_flows)
509{
510 bool next_due, over_target, drop = false;
511 ktime_t schedule;
512 u64 sojourn;
513
514/* The 'schedule' variable records, in its sign, whether 'now' is before or
515 * after 'drop_next'. This allows 'drop_next' to be updated before the next
516 * scheduling decision is actually branched, without destroying that
517 * information. Similarly, the first 'schedule' value calculated is preserved
518 * in the boolean 'next_due'.
519 *
520 * As for 'drop_next', we take advantage of the fact that 'interval' is both
521 * the delay between first exceeding 'target' and the first signalling event,
522 * *and* the scaling factor for the signalling frequency. It's therefore very
523 * natural to use a single mechanism for both purposes, and eliminates a
524 * significant amount of reference Codel's spaghetti code. To help with this,
525 * both the '0' and '1' entries in the invsqrt cache are 0xFFFFFFFF, as close
526 * as possible to 1.0 in fixed-point.
527 */
528
529 sojourn = ktime_to_ns(ktime_sub(now, cobalt_get_enqueue_time(skb)));
530 schedule = ktime_sub(now, vars->drop_next);
531 over_target = sojourn > p->target &&
532 sojourn > p->mtu_time * bulk_flows * 2 &&
533 sojourn > p->mtu_time * 4;
534 next_due = vars->count && ktime_to_ns(schedule) >= 0;
535
536 vars->ecn_marked = false;
537
538 if (over_target) {
539 if (!vars->dropping) {
540 vars->dropping = true;
541 vars->drop_next = cobalt_control(now,
542 p->interval,
543 vars->rec_inv_sqrt);
544 }
545 if (!vars->count)
546 vars->count = 1;
547 } else if (vars->dropping) {
548 vars->dropping = false;
549 }
550
551 if (next_due && vars->dropping) {
552 /* Use ECN mark if possible, otherwise drop */
553 drop = !(vars->ecn_marked = INET_ECN_set_ce(skb));
554
555 vars->count++;
556 if (!vars->count)
557 vars->count--;
558 cobalt_invsqrt(vars);
559 vars->drop_next = cobalt_control(vars->drop_next,
560 p->interval,
561 vars->rec_inv_sqrt);
562 schedule = ktime_sub(now, vars->drop_next);
563 } else {
564 while (next_due) {
565 vars->count--;
566 cobalt_invsqrt(vars);
567 vars->drop_next = cobalt_control(vars->drop_next,
568 p->interval,
569 vars->rec_inv_sqrt);
570 schedule = ktime_sub(now, vars->drop_next);
571 next_due = vars->count && ktime_to_ns(schedule) >= 0;
572 }
573 }
574
575 /* Simple BLUE implementation. Lack of ECN is deliberate. */
576 if (vars->p_drop)
577 drop |= (prandom_u32() < vars->p_drop);
578
579 /* Overload the drop_next field as an activity timeout */
580 if (!vars->count)
581 vars->drop_next = ktime_add_ns(now, p->interval);
582 else if (ktime_to_ns(schedule) > 0 && !drop)
583 vars->drop_next = now;
584
585 return drop;
586}
587
588static void cake_update_flowkeys(struct flow_keys *keys,
589 const struct sk_buff *skb)
590{
591#if IS_ENABLED(CONFIG_NF_CONNTRACK)
592 struct nf_conntrack_tuple tuple = {};
593 bool rev = !skb->_nfct;
594
595 if (tc_skb_protocol(skb) != htons(ETH_P_IP))
596 return;
597
598 if (!nf_ct_get_tuple_skb(&tuple, skb))
599 return;
600
601 keys->addrs.v4addrs.src = rev ? tuple.dst.u3.ip : tuple.src.u3.ip;
602 keys->addrs.v4addrs.dst = rev ? tuple.src.u3.ip : tuple.dst.u3.ip;
603
604 if (keys->ports.ports) {
605 keys->ports.src = rev ? tuple.dst.u.all : tuple.src.u.all;
606 keys->ports.dst = rev ? tuple.src.u.all : tuple.dst.u.all;
607 }
608#endif
609}
610
611/* Cake has several subtle multiple bit settings. In these cases you
612 * would be matching triple isolate mode as well.
613 */
614
615static bool cake_dsrc(int flow_mode)
616{
617 return (flow_mode & CAKE_FLOW_DUAL_SRC) == CAKE_FLOW_DUAL_SRC;
618}
619
620static bool cake_ddst(int flow_mode)
621{
622 return (flow_mode & CAKE_FLOW_DUAL_DST) == CAKE_FLOW_DUAL_DST;
623}
624
625static u32 cake_hash(struct cake_tin_data *q, const struct sk_buff *skb,
626 int flow_mode, u16 flow_override, u16 host_override)
627{
628 u32 flow_hash = 0, srchost_hash = 0, dsthost_hash = 0;
629 u16 reduced_hash, srchost_idx, dsthost_idx;
630 struct flow_keys keys, host_keys;
631
632 if (unlikely(flow_mode == CAKE_FLOW_NONE))
633 return 0;
634
635 /* If both overrides are set we can skip packet dissection entirely */
636 if ((flow_override || !(flow_mode & CAKE_FLOW_FLOWS)) &&
637 (host_override || !(flow_mode & CAKE_FLOW_HOSTS)))
638 goto skip_hash;
639
640 skb_flow_dissect_flow_keys(skb, &keys,
641 FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL);
642
643 if (flow_mode & CAKE_FLOW_NAT_FLAG)
644 cake_update_flowkeys(&keys, skb);
645
646 /* flow_hash_from_keys() sorts the addresses by value, so we have
647 * to preserve their order in a separate data structure to treat
648 * src and dst host addresses as independently selectable.
649 */
650 host_keys = keys;
651 host_keys.ports.ports = 0;
652 host_keys.basic.ip_proto = 0;
653 host_keys.keyid.keyid = 0;
654 host_keys.tags.flow_label = 0;
655
656 switch (host_keys.control.addr_type) {
657 case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
658 host_keys.addrs.v4addrs.src = 0;
659 dsthost_hash = flow_hash_from_keys(&host_keys);
660 host_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
661 host_keys.addrs.v4addrs.dst = 0;
662 srchost_hash = flow_hash_from_keys(&host_keys);
663 break;
664
665 case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
666 memset(&host_keys.addrs.v6addrs.src, 0,
667 sizeof(host_keys.addrs.v6addrs.src));
668 dsthost_hash = flow_hash_from_keys(&host_keys);
669 host_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src;
670 memset(&host_keys.addrs.v6addrs.dst, 0,
671 sizeof(host_keys.addrs.v6addrs.dst));
672 srchost_hash = flow_hash_from_keys(&host_keys);
673 break;
674
675 default:
676 dsthost_hash = 0;
677 srchost_hash = 0;
678 }
679
680 /* This *must* be after the above switch, since as a
681 * side-effect it sorts the src and dst addresses.
682 */
683 if (flow_mode & CAKE_FLOW_FLOWS)
684 flow_hash = flow_hash_from_keys(&keys);
685
686skip_hash:
687 if (flow_override)
688 flow_hash = flow_override - 1;
689 if (host_override) {
690 dsthost_hash = host_override - 1;
691 srchost_hash = host_override - 1;
692 }
693
694 if (!(flow_mode & CAKE_FLOW_FLOWS)) {
695 if (flow_mode & CAKE_FLOW_SRC_IP)
696 flow_hash ^= srchost_hash;
697
698 if (flow_mode & CAKE_FLOW_DST_IP)
699 flow_hash ^= dsthost_hash;
700 }
701
702 reduced_hash = flow_hash % CAKE_QUEUES;
703
704 /* set-associative hashing */
705 /* fast path if no hash collision (direct lookup succeeds) */
706 if (likely(q->tags[reduced_hash] == flow_hash &&
707 q->flows[reduced_hash].set)) {
708 q->way_directs++;
709 } else {
710 u32 inner_hash = reduced_hash % CAKE_SET_WAYS;
711 u32 outer_hash = reduced_hash - inner_hash;
712 bool allocate_src = false;
713 bool allocate_dst = false;
714 u32 i, k;
715
716 /* check if any active queue in the set is reserved for
717 * this flow.
718 */
719 for (i = 0, k = inner_hash; i < CAKE_SET_WAYS;
720 i++, k = (k + 1) % CAKE_SET_WAYS) {
721 if (q->tags[outer_hash + k] == flow_hash) {
722 if (i)
723 q->way_hits++;
724
725 if (!q->flows[outer_hash + k].set) {
726 /* need to increment host refcnts */
727 allocate_src = cake_dsrc(flow_mode);
728 allocate_dst = cake_ddst(flow_mode);
729 }
730
731 goto found;
732 }
733 }
734
735 /* no queue is reserved for this flow, look for an
736 * empty one.
737 */
738 for (i = 0; i < CAKE_SET_WAYS;
739 i++, k = (k + 1) % CAKE_SET_WAYS) {
740 if (!q->flows[outer_hash + k].set) {
741 q->way_misses++;
742 allocate_src = cake_dsrc(flow_mode);
743 allocate_dst = cake_ddst(flow_mode);
744 goto found;
745 }
746 }
747
748 /* With no empty queues, default to the original
749 * queue, accept the collision, update the host tags.
750 */
751 q->way_collisions++;
752 if (q->flows[outer_hash + k].set == CAKE_SET_BULK) {
753 q->hosts[q->flows[reduced_hash].srchost].srchost_bulk_flow_count--;
754 q->hosts[q->flows[reduced_hash].dsthost].dsthost_bulk_flow_count--;
755 }
756 allocate_src = cake_dsrc(flow_mode);
757 allocate_dst = cake_ddst(flow_mode);
758found:
759 /* reserve queue for future packets in same flow */
760 reduced_hash = outer_hash + k;
761 q->tags[reduced_hash] = flow_hash;
762
763 if (allocate_src) {
764 srchost_idx = srchost_hash % CAKE_QUEUES;
765 inner_hash = srchost_idx % CAKE_SET_WAYS;
766 outer_hash = srchost_idx - inner_hash;
767 for (i = 0, k = inner_hash; i < CAKE_SET_WAYS;
768 i++, k = (k + 1) % CAKE_SET_WAYS) {
769 if (q->hosts[outer_hash + k].srchost_tag ==
770 srchost_hash)
771 goto found_src;
772 }
773 for (i = 0; i < CAKE_SET_WAYS;
774 i++, k = (k + 1) % CAKE_SET_WAYS) {
775 if (!q->hosts[outer_hash + k].srchost_bulk_flow_count)
776 break;
777 }
778 q->hosts[outer_hash + k].srchost_tag = srchost_hash;
779found_src:
780 srchost_idx = outer_hash + k;
781 if (q->flows[reduced_hash].set == CAKE_SET_BULK)
782 q->hosts[srchost_idx].srchost_bulk_flow_count++;
783 q->flows[reduced_hash].srchost = srchost_idx;
784 }
785
786 if (allocate_dst) {
787 dsthost_idx = dsthost_hash % CAKE_QUEUES;
788 inner_hash = dsthost_idx % CAKE_SET_WAYS;
789 outer_hash = dsthost_idx - inner_hash;
790 for (i = 0, k = inner_hash; i < CAKE_SET_WAYS;
791 i++, k = (k + 1) % CAKE_SET_WAYS) {
792 if (q->hosts[outer_hash + k].dsthost_tag ==
793 dsthost_hash)
794 goto found_dst;
795 }
796 for (i = 0; i < CAKE_SET_WAYS;
797 i++, k = (k + 1) % CAKE_SET_WAYS) {
798 if (!q->hosts[outer_hash + k].dsthost_bulk_flow_count)
799 break;
800 }
801 q->hosts[outer_hash + k].dsthost_tag = dsthost_hash;
802found_dst:
803 dsthost_idx = outer_hash + k;
804 if (q->flows[reduced_hash].set == CAKE_SET_BULK)
805 q->hosts[dsthost_idx].dsthost_bulk_flow_count++;
806 q->flows[reduced_hash].dsthost = dsthost_idx;
807 }
808 }
809
810 return reduced_hash;
811}
812
813/* helper functions : might be changed when/if skb use a standard list_head */
814/* remove one skb from head of slot queue */
815
816static struct sk_buff *dequeue_head(struct cake_flow *flow)
817{
818 struct sk_buff *skb = flow->head;
819
820 if (skb) {
821 flow->head = skb->next;
822 skb_mark_not_on_list(skb);
823 }
824
825 return skb;
826}
827
828/* add skb to flow queue (tail add) */
829
830static void flow_queue_add(struct cake_flow *flow, struct sk_buff *skb)
831{
832 if (!flow->head)
833 flow->head = skb;
834 else
835 flow->tail->next = skb;
836 flow->tail = skb;
837 skb->next = NULL;
838}
839
840static struct iphdr *cake_get_iphdr(const struct sk_buff *skb,
841 struct ipv6hdr *buf)
842{
843 unsigned int offset = skb_network_offset(skb);
844 struct iphdr *iph;
845
846 iph = skb_header_pointer(skb, offset, sizeof(struct iphdr), buf);
847
848 if (!iph)
849 return NULL;
850
851 if (iph->version == 4 && iph->protocol == IPPROTO_IPV6)
852 return skb_header_pointer(skb, offset + iph->ihl * 4,
853 sizeof(struct ipv6hdr), buf);
854
855 else if (iph->version == 4)
856 return iph;
857
858 else if (iph->version == 6)
859 return skb_header_pointer(skb, offset, sizeof(struct ipv6hdr),
860 buf);
861
862 return NULL;
863}
864
865static struct tcphdr *cake_get_tcphdr(const struct sk_buff *skb,
866 void *buf, unsigned int bufsize)
867{
868 unsigned int offset = skb_network_offset(skb);
869 const struct ipv6hdr *ipv6h;
870 const struct tcphdr *tcph;
871 const struct iphdr *iph;
872 struct ipv6hdr _ipv6h;
873 struct tcphdr _tcph;
874
875 ipv6h = skb_header_pointer(skb, offset, sizeof(_ipv6h), &_ipv6h);
876
877 if (!ipv6h)
878 return NULL;
879
880 if (ipv6h->version == 4) {
881 iph = (struct iphdr *)ipv6h;
882 offset += iph->ihl * 4;
883
884 /* special-case 6in4 tunnelling, as that is a common way to get
885 * v6 connectivity in the home
886 */
887 if (iph->protocol == IPPROTO_IPV6) {
888 ipv6h = skb_header_pointer(skb, offset,
889 sizeof(_ipv6h), &_ipv6h);
890
891 if (!ipv6h || ipv6h->nexthdr != IPPROTO_TCP)
892 return NULL;
893
894 offset += sizeof(struct ipv6hdr);
895
896 } else if (iph->protocol != IPPROTO_TCP) {
897 return NULL;
898 }
899
900 } else if (ipv6h->version == 6) {
901 if (ipv6h->nexthdr != IPPROTO_TCP)
902 return NULL;
903
904 offset += sizeof(struct ipv6hdr);
905 } else {
906 return NULL;
907 }
908
909 tcph = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph);
910 if (!tcph)
911 return NULL;
912
913 return skb_header_pointer(skb, offset,
914 min(__tcp_hdrlen(tcph), bufsize), buf);
915}
916
917static const void *cake_get_tcpopt(const struct tcphdr *tcph,
918 int code, int *oplen)
919{
920 /* inspired by tcp_parse_options in tcp_input.c */
921 int length = __tcp_hdrlen(tcph) - sizeof(struct tcphdr);
922 const u8 *ptr = (const u8 *)(tcph + 1);
923
924 while (length > 0) {
925 int opcode = *ptr++;
926 int opsize;
927
928 if (opcode == TCPOPT_EOL)
929 break;
930 if (opcode == TCPOPT_NOP) {
931 length--;
932 continue;
933 }
934 opsize = *ptr++;
935 if (opsize < 2 || opsize > length)
936 break;
937
938 if (opcode == code) {
939 *oplen = opsize;
940 return ptr;
941 }
942
943 ptr += opsize - 2;
944 length -= opsize;
945 }
946
947 return NULL;
948}
949
950/* Compare two SACK sequences. A sequence is considered greater if it SACKs more
951 * bytes than the other. In the case where both sequences ACKs bytes that the
952 * other doesn't, A is considered greater. DSACKs in A also makes A be
953 * considered greater.
954 *
955 * @return -1, 0 or 1 as normal compare functions
956 */
957static int cake_tcph_sack_compare(const struct tcphdr *tcph_a,
958 const struct tcphdr *tcph_b)
959{
960 const struct tcp_sack_block_wire *sack_a, *sack_b;
961 u32 ack_seq_a = ntohl(tcph_a->ack_seq);
962 u32 bytes_a = 0, bytes_b = 0;
963 int oplen_a, oplen_b;
964 bool first = true;
965
966 sack_a = cake_get_tcpopt(tcph_a, TCPOPT_SACK, &oplen_a);
967 sack_b = cake_get_tcpopt(tcph_b, TCPOPT_SACK, &oplen_b);
968
969 /* pointers point to option contents */
970 oplen_a -= TCPOLEN_SACK_BASE;
971 oplen_b -= TCPOLEN_SACK_BASE;
972
973 if (sack_a && oplen_a >= sizeof(*sack_a) &&
974 (!sack_b || oplen_b < sizeof(*sack_b)))
975 return -1;
976 else if (sack_b && oplen_b >= sizeof(*sack_b) &&
977 (!sack_a || oplen_a < sizeof(*sack_a)))
978 return 1;
979 else if ((!sack_a || oplen_a < sizeof(*sack_a)) &&
980 (!sack_b || oplen_b < sizeof(*sack_b)))
981 return 0;
982
983 while (oplen_a >= sizeof(*sack_a)) {
984 const struct tcp_sack_block_wire *sack_tmp = sack_b;
985 u32 start_a = get_unaligned_be32(&sack_a->start_seq);
986 u32 end_a = get_unaligned_be32(&sack_a->end_seq);
987 int oplen_tmp = oplen_b;
988 bool found = false;
989
990 /* DSACK; always considered greater to prevent dropping */
991 if (before(start_a, ack_seq_a))
992 return -1;
993
994 bytes_a += end_a - start_a;
995
996 while (oplen_tmp >= sizeof(*sack_tmp)) {
997 u32 start_b = get_unaligned_be32(&sack_tmp->start_seq);
998 u32 end_b = get_unaligned_be32(&sack_tmp->end_seq);
999
1000 /* first time through we count the total size */
1001 if (first)
1002 bytes_b += end_b - start_b;
1003
1004 if (!after(start_b, start_a) && !before(end_b, end_a)) {
1005 found = true;
1006 if (!first)
1007 break;
1008 }
1009 oplen_tmp -= sizeof(*sack_tmp);
1010 sack_tmp++;
1011 }
1012
1013 if (!found)
1014 return -1;
1015
1016 oplen_a -= sizeof(*sack_a);
1017 sack_a++;
1018 first = false;
1019 }
1020
1021 /* If we made it this far, all ranges SACKed by A are covered by B, so
1022 * either the SACKs are equal, or B SACKs more bytes.
1023 */
1024 return bytes_b > bytes_a ? 1 : 0;
1025}
1026
1027static void cake_tcph_get_tstamp(const struct tcphdr *tcph,
1028 u32 *tsval, u32 *tsecr)
1029{
1030 const u8 *ptr;
1031 int opsize;
1032
1033 ptr = cake_get_tcpopt(tcph, TCPOPT_TIMESTAMP, &opsize);
1034
1035 if (ptr && opsize == TCPOLEN_TIMESTAMP) {
1036 *tsval = get_unaligned_be32(ptr);
1037 *tsecr = get_unaligned_be32(ptr + 4);
1038 }
1039}
1040
1041static bool cake_tcph_may_drop(const struct tcphdr *tcph,
1042 u32 tstamp_new, u32 tsecr_new)
1043{
1044 /* inspired by tcp_parse_options in tcp_input.c */
1045 int length = __tcp_hdrlen(tcph) - sizeof(struct tcphdr);
1046 const u8 *ptr = (const u8 *)(tcph + 1);
1047 u32 tstamp, tsecr;
1048
1049 /* 3 reserved flags must be unset to avoid future breakage
1050 * ACK must be set
1051 * ECE/CWR are handled separately
1052 * All other flags URG/PSH/RST/SYN/FIN must be unset
1053 * 0x0FFF0000 = all TCP flags (confirm ACK=1, others zero)
1054 * 0x00C00000 = CWR/ECE (handled separately)
1055 * 0x0F3F0000 = 0x0FFF0000 & ~0x00C00000
1056 */
1057 if (((tcp_flag_word(tcph) &
1058 cpu_to_be32(0x0F3F0000)) != TCP_FLAG_ACK))
1059 return false;
1060
1061 while (length > 0) {
1062 int opcode = *ptr++;
1063 int opsize;
1064
1065 if (opcode == TCPOPT_EOL)
1066 break;
1067 if (opcode == TCPOPT_NOP) {
1068 length--;
1069 continue;
1070 }
1071 opsize = *ptr++;
1072 if (opsize < 2 || opsize > length)
1073 break;
1074
1075 switch (opcode) {
1076 case TCPOPT_MD5SIG: /* doesn't influence state */
1077 break;
1078
1079 case TCPOPT_SACK: /* stricter checking performed later */
1080 if (opsize % 8 != 2)
1081 return false;
1082 break;
1083
1084 case TCPOPT_TIMESTAMP:
1085 /* only drop timestamps lower than new */
1086 if (opsize != TCPOLEN_TIMESTAMP)
1087 return false;
1088 tstamp = get_unaligned_be32(ptr);
1089 tsecr = get_unaligned_be32(ptr + 4);
1090 if (after(tstamp, tstamp_new) ||
1091 after(tsecr, tsecr_new))
1092 return false;
1093 break;
1094
1095 case TCPOPT_MSS: /* these should only be set on SYN */
1096 case TCPOPT_WINDOW:
1097 case TCPOPT_SACK_PERM:
1098 case TCPOPT_FASTOPEN:
1099 case TCPOPT_EXP:
1100 default: /* don't drop if any unknown options are present */
1101 return false;
1102 }
1103
1104 ptr += opsize - 2;
1105 length -= opsize;
1106 }
1107
1108 return true;
1109}
1110
1111static struct sk_buff *cake_ack_filter(struct cake_sched_data *q,
1112 struct cake_flow *flow)
1113{
1114 bool aggressive = q->ack_filter == CAKE_ACK_AGGRESSIVE;
1115 struct sk_buff *elig_ack = NULL, *elig_ack_prev = NULL;
1116 struct sk_buff *skb_check, *skb_prev = NULL;
1117 const struct ipv6hdr *ipv6h, *ipv6h_check;
1118 unsigned char _tcph[64], _tcph_check[64];
1119 const struct tcphdr *tcph, *tcph_check;
1120 const struct iphdr *iph, *iph_check;
1121 struct ipv6hdr _iph, _iph_check;
1122 const struct sk_buff *skb;
1123 int seglen, num_found = 0;
1124 u32 tstamp = 0, tsecr = 0;
1125 __be32 elig_flags = 0;
1126 int sack_comp;
1127
1128 /* no other possible ACKs to filter */
1129 if (flow->head == flow->tail)
1130 return NULL;
1131
1132 skb = flow->tail;
1133 tcph = cake_get_tcphdr(skb, _tcph, sizeof(_tcph));
1134 iph = cake_get_iphdr(skb, &_iph);
1135 if (!tcph)
1136 return NULL;
1137
1138 cake_tcph_get_tstamp(tcph, &tstamp, &tsecr);
1139
1140 /* the 'triggering' packet need only have the ACK flag set.
1141 * also check that SYN is not set, as there won't be any previous ACKs.
1142 */
1143 if ((tcp_flag_word(tcph) &
1144 (TCP_FLAG_ACK | TCP_FLAG_SYN)) != TCP_FLAG_ACK)
1145 return NULL;
1146
1147 /* the 'triggering' ACK is at the tail of the queue, we have already
1148 * returned if it is the only packet in the flow. loop through the rest
1149 * of the queue looking for pure ACKs with the same 5-tuple as the
1150 * triggering one.
1151 */
1152 for (skb_check = flow->head;
1153 skb_check && skb_check != skb;
1154 skb_prev = skb_check, skb_check = skb_check->next) {
1155 iph_check = cake_get_iphdr(skb_check, &_iph_check);
1156 tcph_check = cake_get_tcphdr(skb_check, &_tcph_check,
1157 sizeof(_tcph_check));
1158
1159 /* only TCP packets with matching 5-tuple are eligible, and only
1160 * drop safe headers
1161 */
1162 if (!tcph_check || iph->version != iph_check->version ||
1163 tcph_check->source != tcph->source ||
1164 tcph_check->dest != tcph->dest)
1165 continue;
1166
1167 if (iph_check->version == 4) {
1168 if (iph_check->saddr != iph->saddr ||
1169 iph_check->daddr != iph->daddr)
1170 continue;
1171
1172 seglen = ntohs(iph_check->tot_len) -
1173 (4 * iph_check->ihl);
1174 } else if (iph_check->version == 6) {
1175 ipv6h = (struct ipv6hdr *)iph;
1176 ipv6h_check = (struct ipv6hdr *)iph_check;
1177
1178 if (ipv6_addr_cmp(&ipv6h_check->saddr, &ipv6h->saddr) ||
1179 ipv6_addr_cmp(&ipv6h_check->daddr, &ipv6h->daddr))
1180 continue;
1181
1182 seglen = ntohs(ipv6h_check->payload_len);
1183 } else {
1184 WARN_ON(1); /* shouldn't happen */
1185 continue;
1186 }
1187
1188 /* If the ECE/CWR flags changed from the previous eligible
1189 * packet in the same flow, we should no longer be dropping that
1190 * previous packet as this would lose information.
1191 */
1192 if (elig_ack && (tcp_flag_word(tcph_check) &
1193 (TCP_FLAG_ECE | TCP_FLAG_CWR)) != elig_flags) {
1194 elig_ack = NULL;
1195 elig_ack_prev = NULL;
1196 num_found--;
1197 }
1198
1199 /* Check TCP options and flags, don't drop ACKs with segment
1200 * data, and don't drop ACKs with a higher cumulative ACK
1201 * counter than the triggering packet. Check ACK seqno here to
1202 * avoid parsing SACK options of packets we are going to exclude
1203 * anyway.
1204 */
1205 if (!cake_tcph_may_drop(tcph_check, tstamp, tsecr) ||
1206 (seglen - __tcp_hdrlen(tcph_check)) != 0 ||
1207 after(ntohl(tcph_check->ack_seq), ntohl(tcph->ack_seq)))
1208 continue;
1209
1210 /* Check SACK options. The triggering packet must SACK more data
1211 * than the ACK under consideration, or SACK the same range but
1212 * have a larger cumulative ACK counter. The latter is a
1213 * pathological case, but is contained in the following check
1214 * anyway, just to be safe.
1215 */
1216 sack_comp = cake_tcph_sack_compare(tcph_check, tcph);
1217
1218 if (sack_comp < 0 ||
1219 (ntohl(tcph_check->ack_seq) == ntohl(tcph->ack_seq) &&
1220 sack_comp == 0))
1221 continue;
1222
1223 /* At this point we have found an eligible pure ACK to drop; if
1224 * we are in aggressive mode, we are done. Otherwise, keep
1225 * searching unless this is the second eligible ACK we
1226 * found.
1227 *
1228 * Since we want to drop ACK closest to the head of the queue,
1229 * save the first eligible ACK we find, even if we need to loop
1230 * again.
1231 */
1232 if (!elig_ack) {
1233 elig_ack = skb_check;
1234 elig_ack_prev = skb_prev;
1235 elig_flags = (tcp_flag_word(tcph_check)
1236 & (TCP_FLAG_ECE | TCP_FLAG_CWR));
1237 }
1238
1239 if (num_found++ > 0)
1240 goto found;
1241 }
1242
1243 /* We made it through the queue without finding two eligible ACKs . If
1244 * we found a single eligible ACK we can drop it in aggressive mode if
1245 * we can guarantee that this does not interfere with ECN flag
1246 * information. We ensure this by dropping it only if the enqueued
1247 * packet is consecutive with the eligible ACK, and their flags match.
1248 */
1249 if (elig_ack && aggressive && elig_ack->next == skb &&
1250 (elig_flags == (tcp_flag_word(tcph) &
1251 (TCP_FLAG_ECE | TCP_FLAG_CWR))))
1252 goto found;
1253
1254 return NULL;
1255
1256found:
1257 if (elig_ack_prev)
1258 elig_ack_prev->next = elig_ack->next;
1259 else
1260 flow->head = elig_ack->next;
1261
1262 skb_mark_not_on_list(elig_ack);
1263
1264 return elig_ack;
1265}
1266
1267static u64 cake_ewma(u64 avg, u64 sample, u32 shift)
1268{
1269 avg -= avg >> shift;
1270 avg += sample >> shift;
1271 return avg;
1272}
1273
1274static u32 cake_calc_overhead(struct cake_sched_data *q, u32 len, u32 off)
1275{
1276 if (q->rate_flags & CAKE_FLAG_OVERHEAD)
1277 len -= off;
1278
1279 if (q->max_netlen < len)
1280 q->max_netlen = len;
1281 if (q->min_netlen > len)
1282 q->min_netlen = len;
1283
1284 len += q->rate_overhead;
1285
1286 if (len < q->rate_mpu)
1287 len = q->rate_mpu;
1288
1289 if (q->atm_mode == CAKE_ATM_ATM) {
1290 len += 47;
1291 len /= 48;
1292 len *= 53;
1293 } else if (q->atm_mode == CAKE_ATM_PTM) {
1294 /* Add one byte per 64 bytes or part thereof.
1295 * This is conservative and easier to calculate than the
1296 * precise value.
1297 */
1298 len += (len + 63) / 64;
1299 }
1300
1301 if (q->max_adjlen < len)
1302 q->max_adjlen = len;
1303 if (q->min_adjlen > len)
1304 q->min_adjlen = len;
1305
1306 return len;
1307}
1308
1309static u32 cake_overhead(struct cake_sched_data *q, const struct sk_buff *skb)
1310{
1311 const struct skb_shared_info *shinfo = skb_shinfo(skb);
1312 unsigned int hdr_len, last_len = 0;
1313 u32 off = skb_network_offset(skb);
1314 u32 len = qdisc_pkt_len(skb);
1315 u16 segs = 1;
1316
1317 q->avg_netoff = cake_ewma(q->avg_netoff, off << 16, 8);
1318
1319 if (!shinfo->gso_size)
1320 return cake_calc_overhead(q, len, off);
1321
1322 /* borrowed from qdisc_pkt_len_init() */
1323 hdr_len = skb_transport_header(skb) - skb_mac_header(skb);
1324
1325 /* + transport layer */
1326 if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 |
1327 SKB_GSO_TCPV6))) {
1328 const struct tcphdr *th;
1329 struct tcphdr _tcphdr;
1330
1331 th = skb_header_pointer(skb, skb_transport_offset(skb),
1332 sizeof(_tcphdr), &_tcphdr);
1333 if (likely(th))
1334 hdr_len += __tcp_hdrlen(th);
1335 } else {
1336 struct udphdr _udphdr;
1337
1338 if (skb_header_pointer(skb, skb_transport_offset(skb),
1339 sizeof(_udphdr), &_udphdr))
1340 hdr_len += sizeof(struct udphdr);
1341 }
1342
1343 if (unlikely(shinfo->gso_type & SKB_GSO_DODGY))
1344 segs = DIV_ROUND_UP(skb->len - hdr_len,
1345 shinfo->gso_size);
1346 else
1347 segs = shinfo->gso_segs;
1348
1349 len = shinfo->gso_size + hdr_len;
1350 last_len = skb->len - shinfo->gso_size * (segs - 1);
1351
1352 return (cake_calc_overhead(q, len, off) * (segs - 1) +
1353 cake_calc_overhead(q, last_len, off));
1354}
1355
1356static void cake_heap_swap(struct cake_sched_data *q, u16 i, u16 j)
1357{
1358 struct cake_heap_entry ii = q->overflow_heap[i];
1359 struct cake_heap_entry jj = q->overflow_heap[j];
1360
1361 q->overflow_heap[i] = jj;
1362 q->overflow_heap[j] = ii;
1363
1364 q->tins[ii.t].overflow_idx[ii.b] = j;
1365 q->tins[jj.t].overflow_idx[jj.b] = i;
1366}
1367
1368static u32 cake_heap_get_backlog(const struct cake_sched_data *q, u16 i)
1369{
1370 struct cake_heap_entry ii = q->overflow_heap[i];
1371
1372 return q->tins[ii.t].backlogs[ii.b];
1373}
1374
1375static void cake_heapify(struct cake_sched_data *q, u16 i)
1376{
1377 static const u32 a = CAKE_MAX_TINS * CAKE_QUEUES;
1378 u32 mb = cake_heap_get_backlog(q, i);
1379 u32 m = i;
1380
1381 while (m < a) {
1382 u32 l = m + m + 1;
1383 u32 r = l + 1;
1384
1385 if (l < a) {
1386 u32 lb = cake_heap_get_backlog(q, l);
1387
1388 if (lb > mb) {
1389 m = l;
1390 mb = lb;
1391 }
1392 }
1393
1394 if (r < a) {
1395 u32 rb = cake_heap_get_backlog(q, r);
1396
1397 if (rb > mb) {
1398 m = r;
1399 mb = rb;
1400 }
1401 }
1402
1403 if (m != i) {
1404 cake_heap_swap(q, i, m);
1405 i = m;
1406 } else {
1407 break;
1408 }
1409 }
1410}
1411
1412static void cake_heapify_up(struct cake_sched_data *q, u16 i)
1413{
1414 while (i > 0 && i < CAKE_MAX_TINS * CAKE_QUEUES) {
1415 u16 p = (i - 1) >> 1;
1416 u32 ib = cake_heap_get_backlog(q, i);
1417 u32 pb = cake_heap_get_backlog(q, p);
1418
1419 if (ib > pb) {
1420 cake_heap_swap(q, i, p);
1421 i = p;
1422 } else {
1423 break;
1424 }
1425 }
1426}
1427
1428static int cake_advance_shaper(struct cake_sched_data *q,
1429 struct cake_tin_data *b,
1430 struct sk_buff *skb,
1431 ktime_t now, bool drop)
1432{
1433 u32 len = get_cobalt_cb(skb)->adjusted_len;
1434
1435 /* charge packet bandwidth to this tin
1436 * and to the global shaper.
1437 */
1438 if (q->rate_ns) {
1439 u64 tin_dur = (len * b->tin_rate_ns) >> b->tin_rate_shft;
1440 u64 global_dur = (len * q->rate_ns) >> q->rate_shft;
1441 u64 failsafe_dur = global_dur + (global_dur >> 1);
1442
1443 if (ktime_before(b->time_next_packet, now))
1444 b->time_next_packet = ktime_add_ns(b->time_next_packet,
1445 tin_dur);
1446
1447 else if (ktime_before(b->time_next_packet,
1448 ktime_add_ns(now, tin_dur)))
1449 b->time_next_packet = ktime_add_ns(now, tin_dur);
1450
1451 q->time_next_packet = ktime_add_ns(q->time_next_packet,
1452 global_dur);
1453 if (!drop)
1454 q->failsafe_next_packet = \
1455 ktime_add_ns(q->failsafe_next_packet,
1456 failsafe_dur);
1457 }
1458 return len;
1459}
1460
1461static unsigned int cake_drop(struct Qdisc *sch, struct sk_buff **to_free)
1462{
1463 struct cake_sched_data *q = qdisc_priv(sch);
1464 ktime_t now = ktime_get();
1465 u32 idx = 0, tin = 0, len;
1466 struct cake_heap_entry qq;
1467 struct cake_tin_data *b;
1468 struct cake_flow *flow;
1469 struct sk_buff *skb;
1470
1471 if (!q->overflow_timeout) {
1472 int i;
1473 /* Build fresh max-heap */
1474 for (i = CAKE_MAX_TINS * CAKE_QUEUES / 2; i >= 0; i--)
1475 cake_heapify(q, i);
1476 }
1477 q->overflow_timeout = 65535;
1478
1479 /* select longest queue for pruning */
1480 qq = q->overflow_heap[0];
1481 tin = qq.t;
1482 idx = qq.b;
1483
1484 b = &q->tins[tin];
1485 flow = &b->flows[idx];
1486 skb = dequeue_head(flow);
1487 if (unlikely(!skb)) {
1488 /* heap has gone wrong, rebuild it next time */
1489 q->overflow_timeout = 0;
1490 return idx + (tin << 16);
1491 }
1492
1493 if (cobalt_queue_full(&flow->cvars, &b->cparams, now))
1494 b->unresponsive_flow_count++;
1495
1496 len = qdisc_pkt_len(skb);
1497 q->buffer_used -= skb->truesize;
1498 b->backlogs[idx] -= len;
1499 b->tin_backlog -= len;
1500 sch->qstats.backlog -= len;
1501 qdisc_tree_reduce_backlog(sch, 1, len);
1502
1503 flow->dropped++;
1504 b->tin_dropped++;
1505 sch->qstats.drops++;
1506
1507 if (q->rate_flags & CAKE_FLAG_INGRESS)
1508 cake_advance_shaper(q, b, skb, now, true);
1509
1510 __qdisc_drop(skb, to_free);
1511 sch->q.qlen--;
1512
1513 cake_heapify(q, 0);
1514
1515 return idx + (tin << 16);
1516}
1517
1518static u8 cake_handle_diffserv(struct sk_buff *skb, u16 wash)
1519{
1520 int wlen = skb_network_offset(skb);
1521 u8 dscp;
1522
1523 switch (tc_skb_protocol(skb)) {
1524 case htons(ETH_P_IP):
1525 wlen += sizeof(struct iphdr);
1526 if (!pskb_may_pull(skb, wlen) ||
1527 skb_try_make_writable(skb, wlen))
1528 return 0;
1529
1530 dscp = ipv4_get_dsfield(ip_hdr(skb)) >> 2;
1531 if (wash && dscp)
1532 ipv4_change_dsfield(ip_hdr(skb), INET_ECN_MASK, 0);
1533 return dscp;
1534
1535 case htons(ETH_P_IPV6):
1536 wlen += sizeof(struct ipv6hdr);
1537 if (!pskb_may_pull(skb, wlen) ||
1538 skb_try_make_writable(skb, wlen))
1539 return 0;
1540
1541 dscp = ipv6_get_dsfield(ipv6_hdr(skb)) >> 2;
1542 if (wash && dscp)
1543 ipv6_change_dsfield(ipv6_hdr(skb), INET_ECN_MASK, 0);
1544 return dscp;
1545
1546 case htons(ETH_P_ARP):
1547 return 0x38; /* CS7 - Net Control */
1548
1549 default:
1550 /* If there is no Diffserv field, treat as best-effort */
1551 return 0;
1552 }
1553}
1554
1555static struct cake_tin_data *cake_select_tin(struct Qdisc *sch,
1556 struct sk_buff *skb)
1557{
1558 struct cake_sched_data *q = qdisc_priv(sch);
1559 u32 tin, mark;
1560 u8 dscp;
1561
1562 /* Tin selection: Default to diffserv-based selection, allow overriding
1563 * using firewall marks or skb->priority.
1564 */
1565 dscp = cake_handle_diffserv(skb,
1566 q->rate_flags & CAKE_FLAG_WASH);
1567 mark = (skb->mark & q->fwmark_mask) >> q->fwmark_shft;
1568
1569 if (q->tin_mode == CAKE_DIFFSERV_BESTEFFORT)
1570 tin = 0;
1571
1572 else if (mark && mark <= q->tin_cnt)
1573 tin = q->tin_order[mark - 1];
1574
1575 else if (TC_H_MAJ(skb->priority) == sch->handle &&
1576 TC_H_MIN(skb->priority) > 0 &&
1577 TC_H_MIN(skb->priority) <= q->tin_cnt)
1578 tin = q->tin_order[TC_H_MIN(skb->priority) - 1];
1579
1580 else {
1581 tin = q->tin_index[dscp];
1582
1583 if (unlikely(tin >= q->tin_cnt))
1584 tin = 0;
1585 }
1586
1587 return &q->tins[tin];
1588}
1589
1590static u32 cake_classify(struct Qdisc *sch, struct cake_tin_data **t,
1591 struct sk_buff *skb, int flow_mode, int *qerr)
1592{
1593 struct cake_sched_data *q = qdisc_priv(sch);
1594 struct tcf_proto *filter;
1595 struct tcf_result res;
1596 u16 flow = 0, host = 0;
1597 int result;
1598
1599 filter = rcu_dereference_bh(q->filter_list);
1600 if (!filter)
1601 goto hash;
1602
1603 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
1604 result = tcf_classify(skb, filter, &res, false);
1605
1606 if (result >= 0) {
1607#ifdef CONFIG_NET_CLS_ACT
1608 switch (result) {
1609 case TC_ACT_STOLEN:
1610 case TC_ACT_QUEUED:
1611 case TC_ACT_TRAP:
1612 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
1613 /* fall through */
1614 case TC_ACT_SHOT:
1615 return 0;
1616 }
1617#endif
1618 if (TC_H_MIN(res.classid) <= CAKE_QUEUES)
1619 flow = TC_H_MIN(res.classid);
1620 if (TC_H_MAJ(res.classid) <= (CAKE_QUEUES << 16))
1621 host = TC_H_MAJ(res.classid) >> 16;
1622 }
1623hash:
1624 *t = cake_select_tin(sch, skb);
1625 return cake_hash(*t, skb, flow_mode, flow, host) + 1;
1626}
1627
1628static void cake_reconfigure(struct Qdisc *sch);
1629
1630static s32 cake_enqueue(struct sk_buff *skb, struct Qdisc *sch,
1631 struct sk_buff **to_free)
1632{
1633 struct cake_sched_data *q = qdisc_priv(sch);
1634 int len = qdisc_pkt_len(skb);
1635 int uninitialized_var(ret);
1636 struct sk_buff *ack = NULL;
1637 ktime_t now = ktime_get();
1638 struct cake_tin_data *b;
1639 struct cake_flow *flow;
1640 u32 idx;
1641
1642 /* choose flow to insert into */
1643 idx = cake_classify(sch, &b, skb, q->flow_mode, &ret);
1644 if (idx == 0) {
1645 if (ret & __NET_XMIT_BYPASS)
1646 qdisc_qstats_drop(sch);
1647 __qdisc_drop(skb, to_free);
1648 return ret;
1649 }
1650 idx--;
1651 flow = &b->flows[idx];
1652
1653 /* ensure shaper state isn't stale */
1654 if (!b->tin_backlog) {
1655 if (ktime_before(b->time_next_packet, now))
1656 b->time_next_packet = now;
1657
1658 if (!sch->q.qlen) {
1659 if (ktime_before(q->time_next_packet, now)) {
1660 q->failsafe_next_packet = now;
1661 q->time_next_packet = now;
1662 } else if (ktime_after(q->time_next_packet, now) &&
1663 ktime_after(q->failsafe_next_packet, now)) {
1664 u64 next = \
1665 min(ktime_to_ns(q->time_next_packet),
1666 ktime_to_ns(
1667 q->failsafe_next_packet));
1668 sch->qstats.overlimits++;
1669 qdisc_watchdog_schedule_ns(&q->watchdog, next);
1670 }
1671 }
1672 }
1673
1674 if (unlikely(len > b->max_skblen))
1675 b->max_skblen = len;
1676
1677 if (skb_is_gso(skb) && q->rate_flags & CAKE_FLAG_SPLIT_GSO) {
1678 struct sk_buff *segs, *nskb;
1679 netdev_features_t features = netif_skb_features(skb);
1680 unsigned int slen = 0, numsegs = 0;
1681
1682 segs = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK);
1683 if (IS_ERR_OR_NULL(segs))
1684 return qdisc_drop(skb, sch, to_free);
1685
1686 while (segs) {
1687 nskb = segs->next;
1688 skb_mark_not_on_list(segs);
1689 qdisc_skb_cb(segs)->pkt_len = segs->len;
1690 cobalt_set_enqueue_time(segs, now);
1691 get_cobalt_cb(segs)->adjusted_len = cake_overhead(q,
1692 segs);
1693 flow_queue_add(flow, segs);
1694
1695 sch->q.qlen++;
1696 numsegs++;
1697 slen += segs->len;
1698 q->buffer_used += segs->truesize;
1699 b->packets++;
1700 segs = nskb;
1701 }
1702
1703 /* stats */
1704 b->bytes += slen;
1705 b->backlogs[idx] += slen;
1706 b->tin_backlog += slen;
1707 sch->qstats.backlog += slen;
1708 q->avg_window_bytes += slen;
1709
1710 qdisc_tree_reduce_backlog(sch, 1-numsegs, len-slen);
1711 consume_skb(skb);
1712 } else {
1713 /* not splitting */
1714 cobalt_set_enqueue_time(skb, now);
1715 get_cobalt_cb(skb)->adjusted_len = cake_overhead(q, skb);
1716 flow_queue_add(flow, skb);
1717
1718 if (q->ack_filter)
1719 ack = cake_ack_filter(q, flow);
1720
1721 if (ack) {
1722 b->ack_drops++;
1723 sch->qstats.drops++;
1724 b->bytes += qdisc_pkt_len(ack);
1725 len -= qdisc_pkt_len(ack);
1726 q->buffer_used += skb->truesize - ack->truesize;
1727 if (q->rate_flags & CAKE_FLAG_INGRESS)
1728 cake_advance_shaper(q, b, ack, now, true);
1729
1730 qdisc_tree_reduce_backlog(sch, 1, qdisc_pkt_len(ack));
1731 consume_skb(ack);
1732 } else {
1733 sch->q.qlen++;
1734 q->buffer_used += skb->truesize;
1735 }
1736
1737 /* stats */
1738 b->packets++;
1739 b->bytes += len;
1740 b->backlogs[idx] += len;
1741 b->tin_backlog += len;
1742 sch->qstats.backlog += len;
1743 q->avg_window_bytes += len;
1744 }
1745
1746 if (q->overflow_timeout)
1747 cake_heapify_up(q, b->overflow_idx[idx]);
1748
1749 /* incoming bandwidth capacity estimate */
1750 if (q->rate_flags & CAKE_FLAG_AUTORATE_INGRESS) {
1751 u64 packet_interval = \
1752 ktime_to_ns(ktime_sub(now, q->last_packet_time));
1753
1754 if (packet_interval > NSEC_PER_SEC)
1755 packet_interval = NSEC_PER_SEC;
1756
1757 /* filter out short-term bursts, eg. wifi aggregation */
1758 q->avg_packet_interval = \
1759 cake_ewma(q->avg_packet_interval,
1760 packet_interval,
1761 (packet_interval > q->avg_packet_interval ?
1762 2 : 8));
1763
1764 q->last_packet_time = now;
1765
1766 if (packet_interval > q->avg_packet_interval) {
1767 u64 window_interval = \
1768 ktime_to_ns(ktime_sub(now,
1769 q->avg_window_begin));
1770 u64 b = q->avg_window_bytes * (u64)NSEC_PER_SEC;
1771
1772 do_div(b, window_interval);
1773 q->avg_peak_bandwidth =
1774 cake_ewma(q->avg_peak_bandwidth, b,
1775 b > q->avg_peak_bandwidth ? 2 : 8);
1776 q->avg_window_bytes = 0;
1777 q->avg_window_begin = now;
1778
1779 if (ktime_after(now,
1780 ktime_add_ms(q->last_reconfig_time,
1781 250))) {
1782 q->rate_bps = (q->avg_peak_bandwidth * 15) >> 4;
1783 cake_reconfigure(sch);
1784 }
1785 }
1786 } else {
1787 q->avg_window_bytes = 0;
1788 q->last_packet_time = now;
1789 }
1790
1791 /* flowchain */
1792 if (!flow->set || flow->set == CAKE_SET_DECAYING) {
1793 struct cake_host *srchost = &b->hosts[flow->srchost];
1794 struct cake_host *dsthost = &b->hosts[flow->dsthost];
1795 u16 host_load = 1;
1796
1797 if (!flow->set) {
1798 list_add_tail(&flow->flowchain, &b->new_flows);
1799 } else {
1800 b->decaying_flow_count--;
1801 list_move_tail(&flow->flowchain, &b->new_flows);
1802 }
1803 flow->set = CAKE_SET_SPARSE;
1804 b->sparse_flow_count++;
1805
1806 if (cake_dsrc(q->flow_mode))
1807 host_load = max(host_load, srchost->srchost_bulk_flow_count);
1808
1809 if (cake_ddst(q->flow_mode))
1810 host_load = max(host_load, dsthost->dsthost_bulk_flow_count);
1811
1812 flow->deficit = (b->flow_quantum *
1813 quantum_div[host_load]) >> 16;
1814 } else if (flow->set == CAKE_SET_SPARSE_WAIT) {
1815 struct cake_host *srchost = &b->hosts[flow->srchost];
1816 struct cake_host *dsthost = &b->hosts[flow->dsthost];
1817
1818 /* this flow was empty, accounted as a sparse flow, but actually
1819 * in the bulk rotation.
1820 */
1821 flow->set = CAKE_SET_BULK;
1822 b->sparse_flow_count--;
1823 b->bulk_flow_count++;
1824
1825 if (cake_dsrc(q->flow_mode))
1826 srchost->srchost_bulk_flow_count++;
1827
1828 if (cake_ddst(q->flow_mode))
1829 dsthost->dsthost_bulk_flow_count++;
1830
1831 }
1832
1833 if (q->buffer_used > q->buffer_max_used)
1834 q->buffer_max_used = q->buffer_used;
1835
1836 if (q->buffer_used > q->buffer_limit) {
1837 u32 dropped = 0;
1838
1839 while (q->buffer_used > q->buffer_limit) {
1840 dropped++;
1841 cake_drop(sch, to_free);
1842 }
1843 b->drop_overlimit += dropped;
1844 }
1845 return NET_XMIT_SUCCESS;
1846}
1847
1848static struct sk_buff *cake_dequeue_one(struct Qdisc *sch)
1849{
1850 struct cake_sched_data *q = qdisc_priv(sch);
1851 struct cake_tin_data *b = &q->tins[q->cur_tin];
1852 struct cake_flow *flow = &b->flows[q->cur_flow];
1853 struct sk_buff *skb = NULL;
1854 u32 len;
1855
1856 if (flow->head) {
1857 skb = dequeue_head(flow);
1858 len = qdisc_pkt_len(skb);
1859 b->backlogs[q->cur_flow] -= len;
1860 b->tin_backlog -= len;
1861 sch->qstats.backlog -= len;
1862 q->buffer_used -= skb->truesize;
1863 sch->q.qlen--;
1864
1865 if (q->overflow_timeout)
1866 cake_heapify(q, b->overflow_idx[q->cur_flow]);
1867 }
1868 return skb;
1869}
1870
1871/* Discard leftover packets from a tin no longer in use. */
1872static void cake_clear_tin(struct Qdisc *sch, u16 tin)
1873{
1874 struct cake_sched_data *q = qdisc_priv(sch);
1875 struct sk_buff *skb;
1876
1877 q->cur_tin = tin;
1878 for (q->cur_flow = 0; q->cur_flow < CAKE_QUEUES; q->cur_flow++)
1879 while (!!(skb = cake_dequeue_one(sch)))
1880 kfree_skb(skb);
1881}
1882
1883static struct sk_buff *cake_dequeue(struct Qdisc *sch)
1884{
1885 struct cake_sched_data *q = qdisc_priv(sch);
1886 struct cake_tin_data *b = &q->tins[q->cur_tin];
1887 struct cake_host *srchost, *dsthost;
1888 ktime_t now = ktime_get();
1889 struct cake_flow *flow;
1890 struct list_head *head;
1891 bool first_flow = true;
1892 struct sk_buff *skb;
1893 u16 host_load;
1894 u64 delay;
1895 u32 len;
1896
1897begin:
1898 if (!sch->q.qlen)
1899 return NULL;
1900
1901 /* global hard shaper */
1902 if (ktime_after(q->time_next_packet, now) &&
1903 ktime_after(q->failsafe_next_packet, now)) {
1904 u64 next = min(ktime_to_ns(q->time_next_packet),
1905 ktime_to_ns(q->failsafe_next_packet));
1906
1907 sch->qstats.overlimits++;
1908 qdisc_watchdog_schedule_ns(&q->watchdog, next);
1909 return NULL;
1910 }
1911
1912 /* Choose a class to work on. */
1913 if (!q->rate_ns) {
1914 /* In unlimited mode, can't rely on shaper timings, just balance
1915 * with DRR
1916 */
1917 bool wrapped = false, empty = true;
1918
1919 while (b->tin_deficit < 0 ||
1920 !(b->sparse_flow_count + b->bulk_flow_count)) {
1921 if (b->tin_deficit <= 0)
1922 b->tin_deficit += b->tin_quantum_band;
1923 if (b->sparse_flow_count + b->bulk_flow_count)
1924 empty = false;
1925
1926 q->cur_tin++;
1927 b++;
1928 if (q->cur_tin >= q->tin_cnt) {
1929 q->cur_tin = 0;
1930 b = q->tins;
1931
1932 if (wrapped) {
1933 /* It's possible for q->qlen to be
1934 * nonzero when we actually have no
1935 * packets anywhere.
1936 */
1937 if (empty)
1938 return NULL;
1939 } else {
1940 wrapped = true;
1941 }
1942 }
1943 }
1944 } else {
1945 /* In shaped mode, choose:
1946 * - Highest-priority tin with queue and meeting schedule, or
1947 * - The earliest-scheduled tin with queue.
1948 */
1949 ktime_t best_time = KTIME_MAX;
1950 int tin, best_tin = 0;
1951
1952 for (tin = 0; tin < q->tin_cnt; tin++) {
1953 b = q->tins + tin;
1954 if ((b->sparse_flow_count + b->bulk_flow_count) > 0) {
1955 ktime_t time_to_pkt = \
1956 ktime_sub(b->time_next_packet, now);
1957
1958 if (ktime_to_ns(time_to_pkt) <= 0 ||
1959 ktime_compare(time_to_pkt,
1960 best_time) <= 0) {
1961 best_time = time_to_pkt;
1962 best_tin = tin;
1963 }
1964 }
1965 }
1966
1967 q->cur_tin = best_tin;
1968 b = q->tins + best_tin;
1969
1970 /* No point in going further if no packets to deliver. */
1971 if (unlikely(!(b->sparse_flow_count + b->bulk_flow_count)))
1972 return NULL;
1973 }
1974
1975retry:
1976 /* service this class */
1977 head = &b->decaying_flows;
1978 if (!first_flow || list_empty(head)) {
1979 head = &b->new_flows;
1980 if (list_empty(head)) {
1981 head = &b->old_flows;
1982 if (unlikely(list_empty(head))) {
1983 head = &b->decaying_flows;
1984 if (unlikely(list_empty(head)))
1985 goto begin;
1986 }
1987 }
1988 }
1989 flow = list_first_entry(head, struct cake_flow, flowchain);
1990 q->cur_flow = flow - b->flows;
1991 first_flow = false;
1992
1993 /* triple isolation (modified DRR++) */
1994 srchost = &b->hosts[flow->srchost];
1995 dsthost = &b->hosts[flow->dsthost];
1996 host_load = 1;
1997
1998 /* flow isolation (DRR++) */
1999 if (flow->deficit <= 0) {
2000 /* Keep all flows with deficits out of the sparse and decaying
2001 * rotations. No non-empty flow can go into the decaying
2002 * rotation, so they can't get deficits
2003 */
2004 if (flow->set == CAKE_SET_SPARSE) {
2005 if (flow->head) {
2006 b->sparse_flow_count--;
2007 b->bulk_flow_count++;
2008
2009 if (cake_dsrc(q->flow_mode))
2010 srchost->srchost_bulk_flow_count++;
2011
2012 if (cake_ddst(q->flow_mode))
2013 dsthost->dsthost_bulk_flow_count++;
2014
2015 flow->set = CAKE_SET_BULK;
2016 } else {
2017 /* we've moved it to the bulk rotation for
2018 * correct deficit accounting but we still want
2019 * to count it as a sparse flow, not a bulk one.
2020 */
2021 flow->set = CAKE_SET_SPARSE_WAIT;
2022 }
2023 }
2024
2025 if (cake_dsrc(q->flow_mode))
2026 host_load = max(host_load, srchost->srchost_bulk_flow_count);
2027
2028 if (cake_ddst(q->flow_mode))
2029 host_load = max(host_load, dsthost->dsthost_bulk_flow_count);
2030
2031 WARN_ON(host_load > CAKE_QUEUES);
2032
2033 /* The shifted prandom_u32() is a way to apply dithering to
2034 * avoid accumulating roundoff errors
2035 */
2036 flow->deficit += (b->flow_quantum * quantum_div[host_load] +
2037 (prandom_u32() >> 16)) >> 16;
2038 list_move_tail(&flow->flowchain, &b->old_flows);
2039
2040 goto retry;
2041 }
2042
2043 /* Retrieve a packet via the AQM */
2044 while (1) {
2045 skb = cake_dequeue_one(sch);
2046 if (!skb) {
2047 /* this queue was actually empty */
2048 if (cobalt_queue_empty(&flow->cvars, &b->cparams, now))
2049 b->unresponsive_flow_count--;
2050
2051 if (flow->cvars.p_drop || flow->cvars.count ||
2052 ktime_before(now, flow->cvars.drop_next)) {
2053 /* keep in the flowchain until the state has
2054 * decayed to rest
2055 */
2056 list_move_tail(&flow->flowchain,
2057 &b->decaying_flows);
2058 if (flow->set == CAKE_SET_BULK) {
2059 b->bulk_flow_count--;
2060
2061 if (cake_dsrc(q->flow_mode))
2062 srchost->srchost_bulk_flow_count--;
2063
2064 if (cake_ddst(q->flow_mode))
2065 dsthost->dsthost_bulk_flow_count--;
2066
2067 b->decaying_flow_count++;
2068 } else if (flow->set == CAKE_SET_SPARSE ||
2069 flow->set == CAKE_SET_SPARSE_WAIT) {
2070 b->sparse_flow_count--;
2071 b->decaying_flow_count++;
2072 }
2073 flow->set = CAKE_SET_DECAYING;
2074 } else {
2075 /* remove empty queue from the flowchain */
2076 list_del_init(&flow->flowchain);
2077 if (flow->set == CAKE_SET_SPARSE ||
2078 flow->set == CAKE_SET_SPARSE_WAIT)
2079 b->sparse_flow_count--;
2080 else if (flow->set == CAKE_SET_BULK) {
2081 b->bulk_flow_count--;
2082
2083 if (cake_dsrc(q->flow_mode))
2084 srchost->srchost_bulk_flow_count--;
2085
2086 if (cake_ddst(q->flow_mode))
2087 dsthost->dsthost_bulk_flow_count--;
2088
2089 } else
2090 b->decaying_flow_count--;
2091
2092 flow->set = CAKE_SET_NONE;
2093 }
2094 goto begin;
2095 }
2096
2097 /* Last packet in queue may be marked, shouldn't be dropped */
2098 if (!cobalt_should_drop(&flow->cvars, &b->cparams, now, skb,
2099 (b->bulk_flow_count *
2100 !!(q->rate_flags &
2101 CAKE_FLAG_INGRESS))) ||
2102 !flow->head)
2103 break;
2104
2105 /* drop this packet, get another one */
2106 if (q->rate_flags & CAKE_FLAG_INGRESS) {
2107 len = cake_advance_shaper(q, b, skb,
2108 now, true);
2109 flow->deficit -= len;
2110 b->tin_deficit -= len;
2111 }
2112 flow->dropped++;
2113 b->tin_dropped++;
2114 qdisc_tree_reduce_backlog(sch, 1, qdisc_pkt_len(skb));
2115 qdisc_qstats_drop(sch);
2116 kfree_skb(skb);
2117 if (q->rate_flags & CAKE_FLAG_INGRESS)
2118 goto retry;
2119 }
2120
2121 b->tin_ecn_mark += !!flow->cvars.ecn_marked;
2122 qdisc_bstats_update(sch, skb);
2123
2124 /* collect delay stats */
2125 delay = ktime_to_ns(ktime_sub(now, cobalt_get_enqueue_time(skb)));
2126 b->avge_delay = cake_ewma(b->avge_delay, delay, 8);
2127 b->peak_delay = cake_ewma(b->peak_delay, delay,
2128 delay > b->peak_delay ? 2 : 8);
2129 b->base_delay = cake_ewma(b->base_delay, delay,
2130 delay < b->base_delay ? 2 : 8);
2131
2132 len = cake_advance_shaper(q, b, skb, now, false);
2133 flow->deficit -= len;
2134 b->tin_deficit -= len;
2135
2136 if (ktime_after(q->time_next_packet, now) && sch->q.qlen) {
2137 u64 next = min(ktime_to_ns(q->time_next_packet),
2138 ktime_to_ns(q->failsafe_next_packet));
2139
2140 qdisc_watchdog_schedule_ns(&q->watchdog, next);
2141 } else if (!sch->q.qlen) {
2142 int i;
2143
2144 for (i = 0; i < q->tin_cnt; i++) {
2145 if (q->tins[i].decaying_flow_count) {
2146 ktime_t next = \
2147 ktime_add_ns(now,
2148 q->tins[i].cparams.target);
2149
2150 qdisc_watchdog_schedule_ns(&q->watchdog,
2151 ktime_to_ns(next));
2152 break;
2153 }
2154 }
2155 }
2156
2157 if (q->overflow_timeout)
2158 q->overflow_timeout--;
2159
2160 return skb;
2161}
2162
2163static void cake_reset(struct Qdisc *sch)
2164{
2165 u32 c;
2166
2167 for (c = 0; c < CAKE_MAX_TINS; c++)
2168 cake_clear_tin(sch, c);
2169}
2170
2171static const struct nla_policy cake_policy[TCA_CAKE_MAX + 1] = {
2172 [TCA_CAKE_BASE_RATE64] = { .type = NLA_U64 },
2173 [TCA_CAKE_DIFFSERV_MODE] = { .type = NLA_U32 },
2174 [TCA_CAKE_ATM] = { .type = NLA_U32 },
2175 [TCA_CAKE_FLOW_MODE] = { .type = NLA_U32 },
2176 [TCA_CAKE_OVERHEAD] = { .type = NLA_S32 },
2177 [TCA_CAKE_RTT] = { .type = NLA_U32 },
2178 [TCA_CAKE_TARGET] = { .type = NLA_U32 },
2179 [TCA_CAKE_AUTORATE] = { .type = NLA_U32 },
2180 [TCA_CAKE_MEMORY] = { .type = NLA_U32 },
2181 [TCA_CAKE_NAT] = { .type = NLA_U32 },
2182 [TCA_CAKE_RAW] = { .type = NLA_U32 },
2183 [TCA_CAKE_WASH] = { .type = NLA_U32 },
2184 [TCA_CAKE_MPU] = { .type = NLA_U32 },
2185 [TCA_CAKE_INGRESS] = { .type = NLA_U32 },
2186 [TCA_CAKE_ACK_FILTER] = { .type = NLA_U32 },
2187 [TCA_CAKE_FWMARK] = { .type = NLA_U32 },
2188};
2189
2190static void cake_set_rate(struct cake_tin_data *b, u64 rate, u32 mtu,
2191 u64 target_ns, u64 rtt_est_ns)
2192{
2193 /* convert byte-rate into time-per-byte
2194 * so it will always unwedge in reasonable time.
2195 */
2196 static const u64 MIN_RATE = 64;
2197 u32 byte_target = mtu;
2198 u64 byte_target_ns;
2199 u8 rate_shft = 0;
2200 u64 rate_ns = 0;
2201
2202 b->flow_quantum = 1514;
2203 if (rate) {
2204 b->flow_quantum = max(min(rate >> 12, 1514ULL), 300ULL);
2205 rate_shft = 34;
2206 rate_ns = ((u64)NSEC_PER_SEC) << rate_shft;
2207 rate_ns = div64_u64(rate_ns, max(MIN_RATE, rate));
2208 while (!!(rate_ns >> 34)) {
2209 rate_ns >>= 1;
2210 rate_shft--;
2211 }
2212 } /* else unlimited, ie. zero delay */
2213
2214 b->tin_rate_bps = rate;
2215 b->tin_rate_ns = rate_ns;
2216 b->tin_rate_shft = rate_shft;
2217
2218 byte_target_ns = (byte_target * rate_ns) >> rate_shft;
2219
2220 b->cparams.target = max((byte_target_ns * 3) / 2, target_ns);
2221 b->cparams.interval = max(rtt_est_ns +
2222 b->cparams.target - target_ns,
2223 b->cparams.target * 2);
2224 b->cparams.mtu_time = byte_target_ns;
2225 b->cparams.p_inc = 1 << 24; /* 1/256 */
2226 b->cparams.p_dec = 1 << 20; /* 1/4096 */
2227}
2228
2229static int cake_config_besteffort(struct Qdisc *sch)
2230{
2231 struct cake_sched_data *q = qdisc_priv(sch);
2232 struct cake_tin_data *b = &q->tins[0];
2233 u32 mtu = psched_mtu(qdisc_dev(sch));
2234 u64 rate = q->rate_bps;
2235
2236 q->tin_cnt = 1;
2237
2238 q->tin_index = besteffort;
2239 q->tin_order = normal_order;
2240
2241 cake_set_rate(b, rate, mtu,
2242 us_to_ns(q->target), us_to_ns(q->interval));
2243 b->tin_quantum_band = 65535;
2244 b->tin_quantum_prio = 65535;
2245
2246 return 0;
2247}
2248
2249static int cake_config_precedence(struct Qdisc *sch)
2250{
2251 /* convert high-level (user visible) parameters into internal format */
2252 struct cake_sched_data *q = qdisc_priv(sch);
2253 u32 mtu = psched_mtu(qdisc_dev(sch));
2254 u64 rate = q->rate_bps;
2255 u32 quantum1 = 256;
2256 u32 quantum2 = 256;
2257 u32 i;
2258
2259 q->tin_cnt = 8;
2260 q->tin_index = precedence;
2261 q->tin_order = normal_order;
2262
2263 for (i = 0; i < q->tin_cnt; i++) {
2264 struct cake_tin_data *b = &q->tins[i];
2265
2266 cake_set_rate(b, rate, mtu, us_to_ns(q->target),
2267 us_to_ns(q->interval));
2268
2269 b->tin_quantum_prio = max_t(u16, 1U, quantum1);
2270 b->tin_quantum_band = max_t(u16, 1U, quantum2);
2271
2272 /* calculate next class's parameters */
2273 rate *= 7;
2274 rate >>= 3;
2275
2276 quantum1 *= 3;
2277 quantum1 >>= 1;
2278
2279 quantum2 *= 7;
2280 quantum2 >>= 3;
2281 }
2282
2283 return 0;
2284}
2285
2286/* List of known Diffserv codepoints:
2287 *
2288 * Least Effort (CS1)
2289 * Best Effort (CS0)
2290 * Max Reliability & LLT "Lo" (TOS1)
2291 * Max Throughput (TOS2)
2292 * Min Delay (TOS4)
2293 * LLT "La" (TOS5)
2294 * Assured Forwarding 1 (AF1x) - x3
2295 * Assured Forwarding 2 (AF2x) - x3
2296 * Assured Forwarding 3 (AF3x) - x3
2297 * Assured Forwarding 4 (AF4x) - x3
2298 * Precedence Class 2 (CS2)
2299 * Precedence Class 3 (CS3)
2300 * Precedence Class 4 (CS4)
2301 * Precedence Class 5 (CS5)
2302 * Precedence Class 6 (CS6)
2303 * Precedence Class 7 (CS7)
2304 * Voice Admit (VA)
2305 * Expedited Forwarding (EF)
2306
2307 * Total 25 codepoints.
2308 */
2309
2310/* List of traffic classes in RFC 4594:
2311 * (roughly descending order of contended priority)
2312 * (roughly ascending order of uncontended throughput)
2313 *
2314 * Network Control (CS6,CS7) - routing traffic
2315 * Telephony (EF,VA) - aka. VoIP streams
2316 * Signalling (CS5) - VoIP setup
2317 * Multimedia Conferencing (AF4x) - aka. video calls
2318 * Realtime Interactive (CS4) - eg. games
2319 * Multimedia Streaming (AF3x) - eg. YouTube, NetFlix, Twitch
2320 * Broadcast Video (CS3)
2321 * Low Latency Data (AF2x,TOS4) - eg. database
2322 * Ops, Admin, Management (CS2,TOS1) - eg. ssh
2323 * Standard Service (CS0 & unrecognised codepoints)
2324 * High Throughput Data (AF1x,TOS2) - eg. web traffic
2325 * Low Priority Data (CS1) - eg. BitTorrent
2326
2327 * Total 12 traffic classes.
2328 */
2329
2330static int cake_config_diffserv8(struct Qdisc *sch)
2331{
2332/* Pruned list of traffic classes for typical applications:
2333 *
2334 * Network Control (CS6, CS7)
2335 * Minimum Latency (EF, VA, CS5, CS4)
2336 * Interactive Shell (CS2, TOS1)
2337 * Low Latency Transactions (AF2x, TOS4)
2338 * Video Streaming (AF4x, AF3x, CS3)
2339 * Bog Standard (CS0 etc.)
2340 * High Throughput (AF1x, TOS2)
2341 * Background Traffic (CS1)
2342 *
2343 * Total 8 traffic classes.
2344 */
2345
2346 struct cake_sched_data *q = qdisc_priv(sch);
2347 u32 mtu = psched_mtu(qdisc_dev(sch));
2348 u64 rate = q->rate_bps;
2349 u32 quantum1 = 256;
2350 u32 quantum2 = 256;
2351 u32 i;
2352
2353 q->tin_cnt = 8;
2354
2355 /* codepoint to class mapping */
2356 q->tin_index = diffserv8;
2357 q->tin_order = normal_order;
2358
2359 /* class characteristics */
2360 for (i = 0; i < q->tin_cnt; i++) {
2361 struct cake_tin_data *b = &q->tins[i];
2362
2363 cake_set_rate(b, rate, mtu, us_to_ns(q->target),
2364 us_to_ns(q->interval));
2365
2366 b->tin_quantum_prio = max_t(u16, 1U, quantum1);
2367 b->tin_quantum_band = max_t(u16, 1U, quantum2);
2368
2369 /* calculate next class's parameters */
2370 rate *= 7;
2371 rate >>= 3;
2372
2373 quantum1 *= 3;
2374 quantum1 >>= 1;
2375
2376 quantum2 *= 7;
2377 quantum2 >>= 3;
2378 }
2379
2380 return 0;
2381}
2382
2383static int cake_config_diffserv4(struct Qdisc *sch)
2384{
2385/* Further pruned list of traffic classes for four-class system:
2386 *
2387 * Latency Sensitive (CS7, CS6, EF, VA, CS5, CS4)
2388 * Streaming Media (AF4x, AF3x, CS3, AF2x, TOS4, CS2, TOS1)
2389 * Best Effort (CS0, AF1x, TOS2, and those not specified)
2390 * Background Traffic (CS1)
2391 *
2392 * Total 4 traffic classes.
2393 */
2394
2395 struct cake_sched_data *q = qdisc_priv(sch);
2396 u32 mtu = psched_mtu(qdisc_dev(sch));
2397 u64 rate = q->rate_bps;
2398 u32 quantum = 1024;
2399
2400 q->tin_cnt = 4;
2401
2402 /* codepoint to class mapping */
2403 q->tin_index = diffserv4;
2404 q->tin_order = bulk_order;
2405
2406 /* class characteristics */
2407 cake_set_rate(&q->tins[0], rate, mtu,
2408 us_to_ns(q->target), us_to_ns(q->interval));
2409 cake_set_rate(&q->tins[1], rate >> 4, mtu,
2410 us_to_ns(q->target), us_to_ns(q->interval));
2411 cake_set_rate(&q->tins[2], rate >> 1, mtu,
2412 us_to_ns(q->target), us_to_ns(q->interval));
2413 cake_set_rate(&q->tins[3], rate >> 2, mtu,
2414 us_to_ns(q->target), us_to_ns(q->interval));
2415
2416 /* priority weights */
2417 q->tins[0].tin_quantum_prio = quantum;
2418 q->tins[1].tin_quantum_prio = quantum >> 4;
2419 q->tins[2].tin_quantum_prio = quantum << 2;
2420 q->tins[3].tin_quantum_prio = quantum << 4;
2421
2422 /* bandwidth-sharing weights */
2423 q->tins[0].tin_quantum_band = quantum;
2424 q->tins[1].tin_quantum_band = quantum >> 4;
2425 q->tins[2].tin_quantum_band = quantum >> 1;
2426 q->tins[3].tin_quantum_band = quantum >> 2;
2427
2428 return 0;
2429}
2430
2431static int cake_config_diffserv3(struct Qdisc *sch)
2432{
2433/* Simplified Diffserv structure with 3 tins.
2434 * Low Priority (CS1)
2435 * Best Effort
2436 * Latency Sensitive (TOS4, VA, EF, CS6, CS7)
2437 */
2438 struct cake_sched_data *q = qdisc_priv(sch);
2439 u32 mtu = psched_mtu(qdisc_dev(sch));
2440 u64 rate = q->rate_bps;
2441 u32 quantum = 1024;
2442
2443 q->tin_cnt = 3;
2444
2445 /* codepoint to class mapping */
2446 q->tin_index = diffserv3;
2447 q->tin_order = bulk_order;
2448
2449 /* class characteristics */
2450 cake_set_rate(&q->tins[0], rate, mtu,
2451 us_to_ns(q->target), us_to_ns(q->interval));
2452 cake_set_rate(&q->tins[1], rate >> 4, mtu,
2453 us_to_ns(q->target), us_to_ns(q->interval));
2454 cake_set_rate(&q->tins[2], rate >> 2, mtu,
2455 us_to_ns(q->target), us_to_ns(q->interval));
2456
2457 /* priority weights */
2458 q->tins[0].tin_quantum_prio = quantum;
2459 q->tins[1].tin_quantum_prio = quantum >> 4;
2460 q->tins[2].tin_quantum_prio = quantum << 4;
2461
2462 /* bandwidth-sharing weights */
2463 q->tins[0].tin_quantum_band = quantum;
2464 q->tins[1].tin_quantum_band = quantum >> 4;
2465 q->tins[2].tin_quantum_band = quantum >> 2;
2466
2467 return 0;
2468}
2469
2470static void cake_reconfigure(struct Qdisc *sch)
2471{
2472 struct cake_sched_data *q = qdisc_priv(sch);
2473 int c, ft;
2474
2475 switch (q->tin_mode) {
2476 case CAKE_DIFFSERV_BESTEFFORT:
2477 ft = cake_config_besteffort(sch);
2478 break;
2479
2480 case CAKE_DIFFSERV_PRECEDENCE:
2481 ft = cake_config_precedence(sch);
2482 break;
2483
2484 case CAKE_DIFFSERV_DIFFSERV8:
2485 ft = cake_config_diffserv8(sch);
2486 break;
2487
2488 case CAKE_DIFFSERV_DIFFSERV4:
2489 ft = cake_config_diffserv4(sch);
2490 break;
2491
2492 case CAKE_DIFFSERV_DIFFSERV3:
2493 default:
2494 ft = cake_config_diffserv3(sch);
2495 break;
2496 }
2497
2498 for (c = q->tin_cnt; c < CAKE_MAX_TINS; c++) {
2499 cake_clear_tin(sch, c);
2500 q->tins[c].cparams.mtu_time = q->tins[ft].cparams.mtu_time;
2501 }
2502
2503 q->rate_ns = q->tins[ft].tin_rate_ns;
2504 q->rate_shft = q->tins[ft].tin_rate_shft;
2505
2506 if (q->buffer_config_limit) {
2507 q->buffer_limit = q->buffer_config_limit;
2508 } else if (q->rate_bps) {
2509 u64 t = q->rate_bps * q->interval;
2510
2511 do_div(t, USEC_PER_SEC / 4);
2512 q->buffer_limit = max_t(u32, t, 4U << 20);
2513 } else {
2514 q->buffer_limit = ~0;
2515 }
2516
2517 sch->flags &= ~TCQ_F_CAN_BYPASS;
2518
2519 q->buffer_limit = min(q->buffer_limit,
2520 max(sch->limit * psched_mtu(qdisc_dev(sch)),
2521 q->buffer_config_limit));
2522}
2523
2524static int cake_change(struct Qdisc *sch, struct nlattr *opt,
2525 struct netlink_ext_ack *extack)
2526{
2527 struct cake_sched_data *q = qdisc_priv(sch);
2528 struct nlattr *tb[TCA_CAKE_MAX + 1];
2529 int err;
2530
2531 if (!opt)
2532 return -EINVAL;
2533
2534 err = nla_parse_nested_deprecated(tb, TCA_CAKE_MAX, opt, cake_policy,
2535 extack);
2536 if (err < 0)
2537 return err;
2538
2539 if (tb[TCA_CAKE_NAT]) {
2540#if IS_ENABLED(CONFIG_NF_CONNTRACK)
2541 q->flow_mode &= ~CAKE_FLOW_NAT_FLAG;
2542 q->flow_mode |= CAKE_FLOW_NAT_FLAG *
2543 !!nla_get_u32(tb[TCA_CAKE_NAT]);
2544#else
2545 NL_SET_ERR_MSG_ATTR(extack, tb[TCA_CAKE_NAT],
2546 "No conntrack support in kernel");
2547 return -EOPNOTSUPP;
2548#endif
2549 }
2550
2551 if (tb[TCA_CAKE_BASE_RATE64])
2552 q->rate_bps = nla_get_u64(tb[TCA_CAKE_BASE_RATE64]);
2553
2554 if (tb[TCA_CAKE_DIFFSERV_MODE])
2555 q->tin_mode = nla_get_u32(tb[TCA_CAKE_DIFFSERV_MODE]);
2556
2557 if (tb[TCA_CAKE_WASH]) {
2558 if (!!nla_get_u32(tb[TCA_CAKE_WASH]))
2559 q->rate_flags |= CAKE_FLAG_WASH;
2560 else
2561 q->rate_flags &= ~CAKE_FLAG_WASH;
2562 }
2563
2564 if (tb[TCA_CAKE_FLOW_MODE])
2565 q->flow_mode = ((q->flow_mode & CAKE_FLOW_NAT_FLAG) |
2566 (nla_get_u32(tb[TCA_CAKE_FLOW_MODE]) &
2567 CAKE_FLOW_MASK));
2568
2569 if (tb[TCA_CAKE_ATM])
2570 q->atm_mode = nla_get_u32(tb[TCA_CAKE_ATM]);
2571
2572 if (tb[TCA_CAKE_OVERHEAD]) {
2573 q->rate_overhead = nla_get_s32(tb[TCA_CAKE_OVERHEAD]);
2574 q->rate_flags |= CAKE_FLAG_OVERHEAD;
2575
2576 q->max_netlen = 0;
2577 q->max_adjlen = 0;
2578 q->min_netlen = ~0;
2579 q->min_adjlen = ~0;
2580 }
2581
2582 if (tb[TCA_CAKE_RAW]) {
2583 q->rate_flags &= ~CAKE_FLAG_OVERHEAD;
2584
2585 q->max_netlen = 0;
2586 q->max_adjlen = 0;
2587 q->min_netlen = ~0;
2588 q->min_adjlen = ~0;
2589 }
2590
2591 if (tb[TCA_CAKE_MPU])
2592 q->rate_mpu = nla_get_u32(tb[TCA_CAKE_MPU]);
2593
2594 if (tb[TCA_CAKE_RTT]) {
2595 q->interval = nla_get_u32(tb[TCA_CAKE_RTT]);
2596
2597 if (!q->interval)
2598 q->interval = 1;
2599 }
2600
2601 if (tb[TCA_CAKE_TARGET]) {
2602 q->target = nla_get_u32(tb[TCA_CAKE_TARGET]);
2603
2604 if (!q->target)
2605 q->target = 1;
2606 }
2607
2608 if (tb[TCA_CAKE_AUTORATE]) {
2609 if (!!nla_get_u32(tb[TCA_CAKE_AUTORATE]))
2610 q->rate_flags |= CAKE_FLAG_AUTORATE_INGRESS;
2611 else
2612 q->rate_flags &= ~CAKE_FLAG_AUTORATE_INGRESS;
2613 }
2614
2615 if (tb[TCA_CAKE_INGRESS]) {
2616 if (!!nla_get_u32(tb[TCA_CAKE_INGRESS]))
2617 q->rate_flags |= CAKE_FLAG_INGRESS;
2618 else
2619 q->rate_flags &= ~CAKE_FLAG_INGRESS;
2620 }
2621
2622 if (tb[TCA_CAKE_ACK_FILTER])
2623 q->ack_filter = nla_get_u32(tb[TCA_CAKE_ACK_FILTER]);
2624
2625 if (tb[TCA_CAKE_MEMORY])
2626 q->buffer_config_limit = nla_get_u32(tb[TCA_CAKE_MEMORY]);
2627
2628 if (tb[TCA_CAKE_SPLIT_GSO]) {
2629 if (!!nla_get_u32(tb[TCA_CAKE_SPLIT_GSO]))
2630 q->rate_flags |= CAKE_FLAG_SPLIT_GSO;
2631 else
2632 q->rate_flags &= ~CAKE_FLAG_SPLIT_GSO;
2633 }
2634
2635 if (tb[TCA_CAKE_FWMARK]) {
2636 q->fwmark_mask = nla_get_u32(tb[TCA_CAKE_FWMARK]);
2637 q->fwmark_shft = q->fwmark_mask ? __ffs(q->fwmark_mask) : 0;
2638 }
2639
2640 if (q->tins) {
2641 sch_tree_lock(sch);
2642 cake_reconfigure(sch);
2643 sch_tree_unlock(sch);
2644 }
2645
2646 return 0;
2647}
2648
2649static void cake_destroy(struct Qdisc *sch)
2650{
2651 struct cake_sched_data *q = qdisc_priv(sch);
2652
2653 qdisc_watchdog_cancel(&q->watchdog);
2654 tcf_block_put(q->block);
2655 kvfree(q->tins);
2656}
2657
2658static int cake_init(struct Qdisc *sch, struct nlattr *opt,
2659 struct netlink_ext_ack *extack)
2660{
2661 struct cake_sched_data *q = qdisc_priv(sch);
2662 int i, j, err;
2663
2664 sch->limit = 10240;
2665 q->tin_mode = CAKE_DIFFSERV_DIFFSERV3;
2666 q->flow_mode = CAKE_FLOW_TRIPLE;
2667
2668 q->rate_bps = 0; /* unlimited by default */
2669
2670 q->interval = 100000; /* 100ms default */
2671 q->target = 5000; /* 5ms: codel RFC argues
2672 * for 5 to 10% of interval
2673 */
2674 q->rate_flags |= CAKE_FLAG_SPLIT_GSO;
2675 q->cur_tin = 0;
2676 q->cur_flow = 0;
2677
2678 qdisc_watchdog_init(&q->watchdog, sch);
2679
2680 if (opt) {
2681 int err = cake_change(sch, opt, extack);
2682
2683 if (err)
2684 return err;
2685 }
2686
2687 err = tcf_block_get(&q->block, &q->filter_list, sch, extack);
2688 if (err)
2689 return err;
2690
2691 quantum_div[0] = ~0;
2692 for (i = 1; i <= CAKE_QUEUES; i++)
2693 quantum_div[i] = 65535 / i;
2694
2695 q->tins = kvcalloc(CAKE_MAX_TINS, sizeof(struct cake_tin_data),
2696 GFP_KERNEL);
2697 if (!q->tins)
2698 goto nomem;
2699
2700 for (i = 0; i < CAKE_MAX_TINS; i++) {
2701 struct cake_tin_data *b = q->tins + i;
2702
2703 INIT_LIST_HEAD(&b->new_flows);
2704 INIT_LIST_HEAD(&b->old_flows);
2705 INIT_LIST_HEAD(&b->decaying_flows);
2706 b->sparse_flow_count = 0;
2707 b->bulk_flow_count = 0;
2708 b->decaying_flow_count = 0;
2709
2710 for (j = 0; j < CAKE_QUEUES; j++) {
2711 struct cake_flow *flow = b->flows + j;
2712 u32 k = j * CAKE_MAX_TINS + i;
2713
2714 INIT_LIST_HEAD(&flow->flowchain);
2715 cobalt_vars_init(&flow->cvars);
2716
2717 q->overflow_heap[k].t = i;
2718 q->overflow_heap[k].b = j;
2719 b->overflow_idx[j] = k;
2720 }
2721 }
2722
2723 cake_reconfigure(sch);
2724 q->avg_peak_bandwidth = q->rate_bps;
2725 q->min_netlen = ~0;
2726 q->min_adjlen = ~0;
2727 return 0;
2728
2729nomem:
2730 cake_destroy(sch);
2731 return -ENOMEM;
2732}
2733
2734static int cake_dump(struct Qdisc *sch, struct sk_buff *skb)
2735{
2736 struct cake_sched_data *q = qdisc_priv(sch);
2737 struct nlattr *opts;
2738
2739 opts = nla_nest_start_noflag(skb, TCA_OPTIONS);
2740 if (!opts)
2741 goto nla_put_failure;
2742
2743 if (nla_put_u64_64bit(skb, TCA_CAKE_BASE_RATE64, q->rate_bps,
2744 TCA_CAKE_PAD))
2745 goto nla_put_failure;
2746
2747 if (nla_put_u32(skb, TCA_CAKE_FLOW_MODE,
2748 q->flow_mode & CAKE_FLOW_MASK))
2749 goto nla_put_failure;
2750
2751 if (nla_put_u32(skb, TCA_CAKE_RTT, q->interval))
2752 goto nla_put_failure;
2753
2754 if (nla_put_u32(skb, TCA_CAKE_TARGET, q->target))
2755 goto nla_put_failure;
2756
2757 if (nla_put_u32(skb, TCA_CAKE_MEMORY, q->buffer_config_limit))
2758 goto nla_put_failure;
2759
2760 if (nla_put_u32(skb, TCA_CAKE_AUTORATE,
2761 !!(q->rate_flags & CAKE_FLAG_AUTORATE_INGRESS)))
2762 goto nla_put_failure;
2763
2764 if (nla_put_u32(skb, TCA_CAKE_INGRESS,
2765 !!(q->rate_flags & CAKE_FLAG_INGRESS)))
2766 goto nla_put_failure;
2767
2768 if (nla_put_u32(skb, TCA_CAKE_ACK_FILTER, q->ack_filter))
2769 goto nla_put_failure;
2770
2771 if (nla_put_u32(skb, TCA_CAKE_NAT,
2772 !!(q->flow_mode & CAKE_FLOW_NAT_FLAG)))
2773 goto nla_put_failure;
2774
2775 if (nla_put_u32(skb, TCA_CAKE_DIFFSERV_MODE, q->tin_mode))
2776 goto nla_put_failure;
2777
2778 if (nla_put_u32(skb, TCA_CAKE_WASH,
2779 !!(q->rate_flags & CAKE_FLAG_WASH)))
2780 goto nla_put_failure;
2781
2782 if (nla_put_u32(skb, TCA_CAKE_OVERHEAD, q->rate_overhead))
2783 goto nla_put_failure;
2784
2785 if (!(q->rate_flags & CAKE_FLAG_OVERHEAD))
2786 if (nla_put_u32(skb, TCA_CAKE_RAW, 0))
2787 goto nla_put_failure;
2788
2789 if (nla_put_u32(skb, TCA_CAKE_ATM, q->atm_mode))
2790 goto nla_put_failure;
2791
2792 if (nla_put_u32(skb, TCA_CAKE_MPU, q->rate_mpu))
2793 goto nla_put_failure;
2794
2795 if (nla_put_u32(skb, TCA_CAKE_SPLIT_GSO,
2796 !!(q->rate_flags & CAKE_FLAG_SPLIT_GSO)))
2797 goto nla_put_failure;
2798
2799 if (nla_put_u32(skb, TCA_CAKE_FWMARK, q->fwmark_mask))
2800 goto nla_put_failure;
2801
2802 return nla_nest_end(skb, opts);
2803
2804nla_put_failure:
2805 return -1;
2806}
2807
2808static int cake_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
2809{
2810 struct nlattr *stats = nla_nest_start_noflag(d->skb, TCA_STATS_APP);
2811 struct cake_sched_data *q = qdisc_priv(sch);
2812 struct nlattr *tstats, *ts;
2813 int i;
2814
2815 if (!stats)
2816 return -1;
2817
2818#define PUT_STAT_U32(attr, data) do { \
2819 if (nla_put_u32(d->skb, TCA_CAKE_STATS_ ## attr, data)) \
2820 goto nla_put_failure; \
2821 } while (0)
2822#define PUT_STAT_U64(attr, data) do { \
2823 if (nla_put_u64_64bit(d->skb, TCA_CAKE_STATS_ ## attr, \
2824 data, TCA_CAKE_STATS_PAD)) \
2825 goto nla_put_failure; \
2826 } while (0)
2827
2828 PUT_STAT_U64(CAPACITY_ESTIMATE64, q->avg_peak_bandwidth);
2829 PUT_STAT_U32(MEMORY_LIMIT, q->buffer_limit);
2830 PUT_STAT_U32(MEMORY_USED, q->buffer_max_used);
2831 PUT_STAT_U32(AVG_NETOFF, ((q->avg_netoff + 0x8000) >> 16));
2832 PUT_STAT_U32(MAX_NETLEN, q->max_netlen);
2833 PUT_STAT_U32(MAX_ADJLEN, q->max_adjlen);
2834 PUT_STAT_U32(MIN_NETLEN, q->min_netlen);
2835 PUT_STAT_U32(MIN_ADJLEN, q->min_adjlen);
2836
2837#undef PUT_STAT_U32
2838#undef PUT_STAT_U64
2839
2840 tstats = nla_nest_start_noflag(d->skb, TCA_CAKE_STATS_TIN_STATS);
2841 if (!tstats)
2842 goto nla_put_failure;
2843
2844#define PUT_TSTAT_U32(attr, data) do { \
2845 if (nla_put_u32(d->skb, TCA_CAKE_TIN_STATS_ ## attr, data)) \
2846 goto nla_put_failure; \
2847 } while (0)
2848#define PUT_TSTAT_U64(attr, data) do { \
2849 if (nla_put_u64_64bit(d->skb, TCA_CAKE_TIN_STATS_ ## attr, \
2850 data, TCA_CAKE_TIN_STATS_PAD)) \
2851 goto nla_put_failure; \
2852 } while (0)
2853
2854 for (i = 0; i < q->tin_cnt; i++) {
2855 struct cake_tin_data *b = &q->tins[q->tin_order[i]];
2856
2857 ts = nla_nest_start_noflag(d->skb, i + 1);
2858 if (!ts)
2859 goto nla_put_failure;
2860
2861 PUT_TSTAT_U64(THRESHOLD_RATE64, b->tin_rate_bps);
2862 PUT_TSTAT_U64(SENT_BYTES64, b->bytes);
2863 PUT_TSTAT_U32(BACKLOG_BYTES, b->tin_backlog);
2864
2865 PUT_TSTAT_U32(TARGET_US,
2866 ktime_to_us(ns_to_ktime(b->cparams.target)));
2867 PUT_TSTAT_U32(INTERVAL_US,
2868 ktime_to_us(ns_to_ktime(b->cparams.interval)));
2869
2870 PUT_TSTAT_U32(SENT_PACKETS, b->packets);
2871 PUT_TSTAT_U32(DROPPED_PACKETS, b->tin_dropped);
2872 PUT_TSTAT_U32(ECN_MARKED_PACKETS, b->tin_ecn_mark);
2873 PUT_TSTAT_U32(ACKS_DROPPED_PACKETS, b->ack_drops);
2874
2875 PUT_TSTAT_U32(PEAK_DELAY_US,
2876 ktime_to_us(ns_to_ktime(b->peak_delay)));
2877 PUT_TSTAT_U32(AVG_DELAY_US,
2878 ktime_to_us(ns_to_ktime(b->avge_delay)));
2879 PUT_TSTAT_U32(BASE_DELAY_US,
2880 ktime_to_us(ns_to_ktime(b->base_delay)));
2881
2882 PUT_TSTAT_U32(WAY_INDIRECT_HITS, b->way_hits);
2883 PUT_TSTAT_U32(WAY_MISSES, b->way_misses);
2884 PUT_TSTAT_U32(WAY_COLLISIONS, b->way_collisions);
2885
2886 PUT_TSTAT_U32(SPARSE_FLOWS, b->sparse_flow_count +
2887 b->decaying_flow_count);
2888 PUT_TSTAT_U32(BULK_FLOWS, b->bulk_flow_count);
2889 PUT_TSTAT_U32(UNRESPONSIVE_FLOWS, b->unresponsive_flow_count);
2890 PUT_TSTAT_U32(MAX_SKBLEN, b->max_skblen);
2891
2892 PUT_TSTAT_U32(FLOW_QUANTUM, b->flow_quantum);
2893 nla_nest_end(d->skb, ts);
2894 }
2895
2896#undef PUT_TSTAT_U32
2897#undef PUT_TSTAT_U64
2898
2899 nla_nest_end(d->skb, tstats);
2900 return nla_nest_end(d->skb, stats);
2901
2902nla_put_failure:
2903 nla_nest_cancel(d->skb, stats);
2904 return -1;
2905}
2906
2907static struct Qdisc *cake_leaf(struct Qdisc *sch, unsigned long arg)
2908{
2909 return NULL;
2910}
2911
2912static unsigned long cake_find(struct Qdisc *sch, u32 classid)
2913{
2914 return 0;
2915}
2916
2917static unsigned long cake_bind(struct Qdisc *sch, unsigned long parent,
2918 u32 classid)
2919{
2920 return 0;
2921}
2922
2923static void cake_unbind(struct Qdisc *q, unsigned long cl)
2924{
2925}
2926
2927static struct tcf_block *cake_tcf_block(struct Qdisc *sch, unsigned long cl,
2928 struct netlink_ext_ack *extack)
2929{
2930 struct cake_sched_data *q = qdisc_priv(sch);
2931
2932 if (cl)
2933 return NULL;
2934 return q->block;
2935}
2936
2937static int cake_dump_class(struct Qdisc *sch, unsigned long cl,
2938 struct sk_buff *skb, struct tcmsg *tcm)
2939{
2940 tcm->tcm_handle |= TC_H_MIN(cl);
2941 return 0;
2942}
2943
2944static int cake_dump_class_stats(struct Qdisc *sch, unsigned long cl,
2945 struct gnet_dump *d)
2946{
2947 struct cake_sched_data *q = qdisc_priv(sch);
2948 const struct cake_flow *flow = NULL;
2949 struct gnet_stats_queue qs = { 0 };
2950 struct nlattr *stats;
2951 u32 idx = cl - 1;
2952
2953 if (idx < CAKE_QUEUES * q->tin_cnt) {
2954 const struct cake_tin_data *b = \
2955 &q->tins[q->tin_order[idx / CAKE_QUEUES]];
2956 const struct sk_buff *skb;
2957
2958 flow = &b->flows[idx % CAKE_QUEUES];
2959
2960 if (flow->head) {
2961 sch_tree_lock(sch);
2962 skb = flow->head;
2963 while (skb) {
2964 qs.qlen++;
2965 skb = skb->next;
2966 }
2967 sch_tree_unlock(sch);
2968 }
2969 qs.backlog = b->backlogs[idx % CAKE_QUEUES];
2970 qs.drops = flow->dropped;
2971 }
2972 if (gnet_stats_copy_queue(d, NULL, &qs, qs.qlen) < 0)
2973 return -1;
2974 if (flow) {
2975 ktime_t now = ktime_get();
2976
2977 stats = nla_nest_start_noflag(d->skb, TCA_STATS_APP);
2978 if (!stats)
2979 return -1;
2980
2981#define PUT_STAT_U32(attr, data) do { \
2982 if (nla_put_u32(d->skb, TCA_CAKE_STATS_ ## attr, data)) \
2983 goto nla_put_failure; \
2984 } while (0)
2985#define PUT_STAT_S32(attr, data) do { \
2986 if (nla_put_s32(d->skb, TCA_CAKE_STATS_ ## attr, data)) \
2987 goto nla_put_failure; \
2988 } while (0)
2989
2990 PUT_STAT_S32(DEFICIT, flow->deficit);
2991 PUT_STAT_U32(DROPPING, flow->cvars.dropping);
2992 PUT_STAT_U32(COBALT_COUNT, flow->cvars.count);
2993 PUT_STAT_U32(P_DROP, flow->cvars.p_drop);
2994 if (flow->cvars.p_drop) {
2995 PUT_STAT_S32(BLUE_TIMER_US,
2996 ktime_to_us(
2997 ktime_sub(now,
2998 flow->cvars.blue_timer)));
2999 }
3000 if (flow->cvars.dropping) {
3001 PUT_STAT_S32(DROP_NEXT_US,
3002 ktime_to_us(
3003 ktime_sub(now,
3004 flow->cvars.drop_next)));
3005 }
3006
3007 if (nla_nest_end(d->skb, stats) < 0)
3008 return -1;
3009 }
3010
3011 return 0;
3012
3013nla_put_failure:
3014 nla_nest_cancel(d->skb, stats);
3015 return -1;
3016}
3017
3018static void cake_walk(struct Qdisc *sch, struct qdisc_walker *arg)
3019{
3020 struct cake_sched_data *q = qdisc_priv(sch);
3021 unsigned int i, j;
3022
3023 if (arg->stop)
3024 return;
3025
3026 for (i = 0; i < q->tin_cnt; i++) {
3027 struct cake_tin_data *b = &q->tins[q->tin_order[i]];
3028
3029 for (j = 0; j < CAKE_QUEUES; j++) {
3030 if (list_empty(&b->flows[j].flowchain) ||
3031 arg->count < arg->skip) {
3032 arg->count++;
3033 continue;
3034 }
3035 if (arg->fn(sch, i * CAKE_QUEUES + j + 1, arg) < 0) {
3036 arg->stop = 1;
3037 break;
3038 }
3039 arg->count++;
3040 }
3041 }
3042}
3043
3044static const struct Qdisc_class_ops cake_class_ops = {
3045 .leaf = cake_leaf,
3046 .find = cake_find,
3047 .tcf_block = cake_tcf_block,
3048 .bind_tcf = cake_bind,
3049 .unbind_tcf = cake_unbind,
3050 .dump = cake_dump_class,
3051 .dump_stats = cake_dump_class_stats,
3052 .walk = cake_walk,
3053};
3054
3055static struct Qdisc_ops cake_qdisc_ops __read_mostly = {
3056 .cl_ops = &cake_class_ops,
3057 .id = "cake",
3058 .priv_size = sizeof(struct cake_sched_data),
3059 .enqueue = cake_enqueue,
3060 .dequeue = cake_dequeue,
3061 .peek = qdisc_peek_dequeued,
3062 .init = cake_init,
3063 .reset = cake_reset,
3064 .destroy = cake_destroy,
3065 .change = cake_change,
3066 .dump = cake_dump,
3067 .dump_stats = cake_dump_stats,
3068 .owner = THIS_MODULE,
3069};
3070
3071static int __init cake_module_init(void)
3072{
3073 return register_qdisc(&cake_qdisc_ops);
3074}
3075
3076static void __exit cake_module_exit(void)
3077{
3078 unregister_qdisc(&cake_qdisc_ops);
3079}
3080
3081module_init(cake_module_init)
3082module_exit(cake_module_exit)
3083MODULE_AUTHOR("Jonathan Morton");
3084MODULE_LICENSE("Dual BSD/GPL");
3085MODULE_DESCRIPTION("The CAKE shaper.");