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zircon-guest / third_party / linux / 71317d703c550c819b5465c3a49ce98650089865 / . / net / sched / sch_cake.c
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// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
/* COMMON Applications Kept Enhanced (CAKE) discipline
*
* Copyright (C) 2014-2018 Jonathan Morton <chromatix99@gmail.com>
* Copyright (C) 2015-2018 Toke Høiland-Jørgensen <toke@toke.dk>
* Copyright (C) 2014-2018 Dave Täht <dave.taht@gmail.com>
* Copyright (C) 2015-2018 Sebastian Moeller <moeller0@gmx.de>
* (C) 2015-2018 Kevin Darbyshire-Bryant <kevin@darbyshire-bryant.me.uk>
* Copyright (C) 2017-2018 Ryan Mounce <ryan@mounce.com.au>
*
* The CAKE Principles:
* (or, how to have your cake and eat it too)
*
* This is a combination of several shaping, AQM and FQ techniques into one
* easy-to-use package:
*
* - An overall bandwidth shaper, to move the bottleneck away from dumb CPE
* equipment and bloated MACs. This operates in deficit mode (as in sch_fq),
* eliminating the need for any sort of burst parameter (eg. token bucket
* depth). Burst support is limited to that necessary to overcome scheduling
* latency.
*
* - A Diffserv-aware priority queue, giving more priority to certain classes,
* up to a specified fraction of bandwidth. Above that bandwidth threshold,
* the priority is reduced to avoid starving other tins.
*
* - Each priority tin has a separate Flow Queue system, to isolate traffic
* flows from each other. This prevents a burst on one flow from increasing
* the delay to another. Flows are distributed to queues using a
* set-associative hash function.
*
* - Each queue is actively managed by Cobalt, which is a combination of the
* Codel and Blue AQM algorithms. This serves flows fairly, and signals
* congestion early via ECN (if available) and/or packet drops, to keep
* latency low. The codel parameters are auto-tuned based on the bandwidth
* setting, as is necessary at low bandwidths.
*
* The configuration parameters are kept deliberately simple for ease of use.
* Everything has sane defaults. Complete generality of configuration is *not*
* a goal.
*
* The priority queue operates according to a weighted DRR scheme, combined with
* a bandwidth tracker which reuses the shaper logic to detect which side of the
* bandwidth sharing threshold the tin is operating. This determines whether a
* priority-based weight (high) or a bandwidth-based weight (low) is used for
* that tin in the current pass.
*
* This qdisc was inspired by Eric Dumazet's fq_codel code, which he kindly
* granted us permission to leverage.
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/jiffies.h>
#include <linux/string.h>
#include <linux/in.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/skbuff.h>
#include <linux/jhash.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/reciprocal_div.h>
#include <net/netlink.h>
#include <linux/if_vlan.h>
#include <net/pkt_sched.h>
#include <net/pkt_cls.h>
#include <net/tcp.h>
#include <net/flow_dissector.h>
#if IS_ENABLED(CONFIG_NF_CONNTRACK)
#include <net/netfilter/nf_conntrack_core.h>
#endif
#define CAKE_SET_WAYS (8)
#define CAKE_MAX_TINS (8)
#define CAKE_QUEUES (1024)
#define CAKE_FLOW_MASK 63
#define CAKE_FLOW_NAT_FLAG 64
/* struct cobalt_params - contains codel and blue parameters
* @interval: codel initial drop rate
* @target: maximum persistent sojourn time & blue update rate
* @mtu_time: serialisation delay of maximum-size packet
* @p_inc: increment of blue drop probability (0.32 fxp)
* @p_dec: decrement of blue drop probability (0.32 fxp)
*/
struct cobalt_params {
u64 interval;
u64 target;
u64 mtu_time;
u32 p_inc;
u32 p_dec;
};
/* struct cobalt_vars - contains codel and blue variables
* @count: codel dropping frequency
* @rec_inv_sqrt: reciprocal value of sqrt(count) >> 1
* @drop_next: time to drop next packet, or when we dropped last
* @blue_timer: Blue time to next drop
* @p_drop: BLUE drop probability (0.32 fxp)
* @dropping: set if in dropping state
* @ecn_marked: set if marked
*/
struct cobalt_vars {
u32 count;
u32 rec_inv_sqrt;
ktime_t drop_next;
ktime_t blue_timer;
u32 p_drop;
bool dropping;
bool ecn_marked;
};
enum {
CAKE_SET_NONE = 0,
CAKE_SET_SPARSE,
CAKE_SET_SPARSE_WAIT, /* counted in SPARSE, actually in BULK */
CAKE_SET_BULK,
CAKE_SET_DECAYING
};
struct cake_flow {
/* this stuff is all needed per-flow at dequeue time */
struct sk_buff *head;
struct sk_buff *tail;
struct list_head flowchain;
s32 deficit;
u32 dropped;
struct cobalt_vars cvars;
u16 srchost; /* index into cake_host table */
u16 dsthost;
u8 set;
}; /* please try to keep this structure <= 64 bytes */
struct cake_host {
u32 srchost_tag;
u32 dsthost_tag;
u16 srchost_refcnt;
u16 dsthost_refcnt;
};
struct cake_heap_entry {
u16 t:3, b:10;
};
struct cake_tin_data {
struct cake_flow flows[CAKE_QUEUES];
u32 backlogs[CAKE_QUEUES];
u32 tags[CAKE_QUEUES]; /* for set association */
u16 overflow_idx[CAKE_QUEUES];
struct cake_host hosts[CAKE_QUEUES]; /* for triple isolation */
u16 flow_quantum;
struct cobalt_params cparams;
u32 drop_overlimit;
u16 bulk_flow_count;
u16 sparse_flow_count;
u16 decaying_flow_count;
u16 unresponsive_flow_count;
u32 max_skblen;
struct list_head new_flows;
struct list_head old_flows;
struct list_head decaying_flows;
/* time_next = time_this + ((len * rate_ns) >> rate_shft) */
ktime_t time_next_packet;
u64 tin_rate_ns;
u64 tin_rate_bps;
u16 tin_rate_shft;
u16 tin_quantum_prio;
u16 tin_quantum_band;
s32 tin_deficit;
u32 tin_backlog;
u32 tin_dropped;
u32 tin_ecn_mark;
u32 packets;
u64 bytes;
u32 ack_drops;
/* moving averages */
u64 avge_delay;
u64 peak_delay;
u64 base_delay;
/* hash function stats */
u32 way_directs;
u32 way_hits;
u32 way_misses;
u32 way_collisions;
}; /* number of tins is small, so size of this struct doesn't matter much */
struct cake_sched_data {
struct tcf_proto __rcu *filter_list; /* optional external classifier */
struct tcf_block *block;
struct cake_tin_data *tins;
struct cake_heap_entry overflow_heap[CAKE_QUEUES * CAKE_MAX_TINS];
u16 overflow_timeout;
u16 tin_cnt;
u8 tin_mode;
u8 flow_mode;
u8 ack_filter;
u8 atm_mode;
/* time_next = time_this + ((len * rate_ns) >> rate_shft) */
u16 rate_shft;
ktime_t time_next_packet;
ktime_t failsafe_next_packet;
u64 rate_ns;
u64 rate_bps;
u16 rate_flags;
s16 rate_overhead;
u16 rate_mpu;
u64 interval;
u64 target;
/* resource tracking */
u32 buffer_used;
u32 buffer_max_used;
u32 buffer_limit;
u32 buffer_config_limit;
/* indices for dequeue */
u16 cur_tin;
u16 cur_flow;
struct qdisc_watchdog watchdog;
const u8 *tin_index;
const u8 *tin_order;
/* bandwidth capacity estimate */
ktime_t last_packet_time;
ktime_t avg_window_begin;
u64 avg_packet_interval;
u64 avg_window_bytes;
u64 avg_peak_bandwidth;
ktime_t last_reconfig_time;
/* packet length stats */
u32 avg_netoff;
u16 max_netlen;
u16 max_adjlen;
u16 min_netlen;
u16 min_adjlen;
};
enum {
CAKE_FLAG_OVERHEAD = BIT(0),
CAKE_FLAG_AUTORATE_INGRESS = BIT(1),
CAKE_FLAG_INGRESS = BIT(2),
CAKE_FLAG_WASH = BIT(3),
CAKE_FLAG_SPLIT_GSO = BIT(4)
};
/* COBALT operates the Codel and BLUE algorithms in parallel, in order to
* obtain the best features of each. Codel is excellent on flows which
* respond to congestion signals in a TCP-like way. BLUE is more effective on
* unresponsive flows.
*/
struct cobalt_skb_cb {
ktime_t enqueue_time;
u32 adjusted_len;
};
static u64 us_to_ns(u64 us)
{
return us * NSEC_PER_USEC;
}
static struct cobalt_skb_cb *get_cobalt_cb(const struct sk_buff *skb)
{
qdisc_cb_private_validate(skb, sizeof(struct cobalt_skb_cb));
return (struct cobalt_skb_cb *)qdisc_skb_cb(skb)->data;
}
static ktime_t cobalt_get_enqueue_time(const struct sk_buff *skb)
{
return get_cobalt_cb(skb)->enqueue_time;
}
static void cobalt_set_enqueue_time(struct sk_buff *skb,
ktime_t now)
{
get_cobalt_cb(skb)->enqueue_time = now;
}
static u16 quantum_div[CAKE_QUEUES + 1] = {0};
/* Diffserv lookup tables */
static const u8 precedence[] = {
0, 0, 0, 0, 0, 0, 0, 0,
1, 1, 1, 1, 1, 1, 1, 1,
2, 2, 2, 2, 2, 2, 2, 2,
3, 3, 3, 3, 3, 3, 3, 3,
4, 4, 4, 4, 4, 4, 4, 4,
5, 5, 5, 5, 5, 5, 5, 5,
6, 6, 6, 6, 6, 6, 6, 6,
7, 7, 7, 7, 7, 7, 7, 7,
};
static const u8 diffserv8[] = {
2, 5, 1, 2, 4, 2, 2, 2,
0, 2, 1, 2, 1, 2, 1, 2,
5, 2, 4, 2, 4, 2, 4, 2,
3, 2, 3, 2, 3, 2, 3, 2,
6, 2, 3, 2, 3, 2, 3, 2,
6, 2, 2, 2, 6, 2, 6, 2,
7, 2, 2, 2, 2, 2, 2, 2,
7, 2, 2, 2, 2, 2, 2, 2,
};
static const u8 diffserv4[] = {
0, 2, 0, 0, 2, 0, 0, 0,
1, 0, 0, 0, 0, 0, 0, 0,
2, 0, 2, 0, 2, 0, 2, 0,
2, 0, 2, 0, 2, 0, 2, 0,
3, 0, 2, 0, 2, 0, 2, 0,
3, 0, 0, 0, 3, 0, 3, 0,
3, 0, 0, 0, 0, 0, 0, 0,
3, 0, 0, 0, 0, 0, 0, 0,
};
static const u8 diffserv3[] = {
0, 0, 0, 0, 2, 0, 0, 0,
1, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 2, 0, 2, 0,
2, 0, 0, 0, 0, 0, 0, 0,
2, 0, 0, 0, 0, 0, 0, 0,
};
static const u8 besteffort[] = {
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
};
/* tin priority order for stats dumping */
static const u8 normal_order[] = {0, 1, 2, 3, 4, 5, 6, 7};
static const u8 bulk_order[] = {1, 0, 2, 3};
#define REC_INV_SQRT_CACHE (16)
static u32 cobalt_rec_inv_sqrt_cache[REC_INV_SQRT_CACHE] = {0};
/* http://en.wikipedia.org/wiki/Methods_of_computing_square_roots
* new_invsqrt = (invsqrt / 2) * (3 - count * invsqrt^2)
*
* Here, invsqrt is a fixed point number (< 1.0), 32bit mantissa, aka Q0.32
*/
static void cobalt_newton_step(struct cobalt_vars *vars)
{
u32 invsqrt, invsqrt2;
u64 val;
invsqrt = vars->rec_inv_sqrt;
invsqrt2 = ((u64)invsqrt * invsqrt) >> 32;
val = (3LL << 32) - ((u64)vars->count * invsqrt2);
val >>= 2; /* avoid overflow in following multiply */
val = (val * invsqrt) >> (32 - 2 + 1);
vars->rec_inv_sqrt = val;
}
static void cobalt_invsqrt(struct cobalt_vars *vars)
{
if (vars->count < REC_INV_SQRT_CACHE)
vars->rec_inv_sqrt = cobalt_rec_inv_sqrt_cache[vars->count];
else
cobalt_newton_step(vars);
}
/* There is a big difference in timing between the accurate values placed in
* the cache and the approximations given by a single Newton step for small
* count values, particularly when stepping from count 1 to 2 or vice versa.
* Above 16, a single Newton step gives sufficient accuracy in either
* direction, given the precision stored.
*
* The magnitude of the error when stepping up to count 2 is such as to give
* the value that *should* have been produced at count 4.
*/
static void cobalt_cache_init(void)
{
struct cobalt_vars v;
memset(&v, 0, sizeof(v));
v.rec_inv_sqrt = ~0U;
cobalt_rec_inv_sqrt_cache[0] = v.rec_inv_sqrt;
for (v.count = 1; v.count < REC_INV_SQRT_CACHE; v.count++) {
cobalt_newton_step(&v);
cobalt_newton_step(&v);
cobalt_newton_step(&v);
cobalt_newton_step(&v);
cobalt_rec_inv_sqrt_cache[v.count] = v.rec_inv_sqrt;
}
}
static void cobalt_vars_init(struct cobalt_vars *vars)
{
memset(vars, 0, sizeof(*vars));
if (!cobalt_rec_inv_sqrt_cache[0]) {
cobalt_cache_init();
cobalt_rec_inv_sqrt_cache[0] = ~0;
}
}
/* CoDel control_law is t + interval/sqrt(count)
* We maintain in rec_inv_sqrt the reciprocal value of sqrt(count) to avoid
* both sqrt() and divide operation.
*/
static ktime_t cobalt_control(ktime_t t,
u64 interval,
u32 rec_inv_sqrt)
{
return ktime_add_ns(t, reciprocal_scale(interval,
rec_inv_sqrt));
}
/* Call this when a packet had to be dropped due to queue overflow. Returns
* true if the BLUE state was quiescent before but active after this call.
*/
static bool cobalt_queue_full(struct cobalt_vars *vars,
struct cobalt_params *p,
ktime_t now)
{
bool up = false;
if (ktime_to_ns(ktime_sub(now, vars->blue_timer)) > p->target) {
up = !vars->p_drop;
vars->p_drop += p->p_inc;
if (vars->p_drop < p->p_inc)
vars->p_drop = ~0;
vars->blue_timer = now;
}
vars->dropping = true;
vars->drop_next = now;
if (!vars->count)
vars->count = 1;
return up;
}
/* Call this when the queue was serviced but turned out to be empty. Returns
* true if the BLUE state was active before but quiescent after this call.
*/
static bool cobalt_queue_empty(struct cobalt_vars *vars,
struct cobalt_params *p,
ktime_t now)
{
bool down = false;
if (vars->p_drop &&
ktime_to_ns(ktime_sub(now, vars->blue_timer)) > p->target) {
if (vars->p_drop < p->p_dec)
vars->p_drop = 0;
else
vars->p_drop -= p->p_dec;
vars->blue_timer = now;
down = !vars->p_drop;
}
vars->dropping = false;
if (vars->count && ktime_to_ns(ktime_sub(now, vars->drop_next)) >= 0) {
vars->count--;
cobalt_invsqrt(vars);
vars->drop_next = cobalt_control(vars->drop_next,
p->interval,
vars->rec_inv_sqrt);
}
return down;
}
/* Call this with a freshly dequeued packet for possible congestion marking.
* Returns true as an instruction to drop the packet, false for delivery.
*/
static bool cobalt_should_drop(struct cobalt_vars *vars,
struct cobalt_params *p,
ktime_t now,
struct sk_buff *skb,
u32 bulk_flows)
{
bool next_due, over_target, drop = false;
ktime_t schedule;
u64 sojourn;
/* The 'schedule' variable records, in its sign, whether 'now' is before or
* after 'drop_next'. This allows 'drop_next' to be updated before the next
* scheduling decision is actually branched, without destroying that
* information. Similarly, the first 'schedule' value calculated is preserved
* in the boolean 'next_due'.
*
* As for 'drop_next', we take advantage of the fact that 'interval' is both
* the delay between first exceeding 'target' and the first signalling event,
* *and* the scaling factor for the signalling frequency. It's therefore very
* natural to use a single mechanism for both purposes, and eliminates a
* significant amount of reference Codel's spaghetti code. To help with this,
* both the '0' and '1' entries in the invsqrt cache are 0xFFFFFFFF, as close
* as possible to 1.0 in fixed-point.
*/
sojourn = ktime_to_ns(ktime_sub(now, cobalt_get_enqueue_time(skb)));
schedule = ktime_sub(now, vars->drop_next);
over_target = sojourn > p->target &&
sojourn > p->mtu_time * bulk_flows * 2 &&
sojourn > p->mtu_time * 4;
next_due = vars->count && ktime_to_ns(schedule) >= 0;
vars->ecn_marked = false;
if (over_target) {
if (!vars->dropping) {
vars->dropping = true;
vars->drop_next = cobalt_control(now,
p->interval,
vars->rec_inv_sqrt);
}
if (!vars->count)
vars->count = 1;
} else if (vars->dropping) {
vars->dropping = false;
}
if (next_due && vars->dropping) {
/* Use ECN mark if possible, otherwise drop */
drop = !(vars->ecn_marked = INET_ECN_set_ce(skb));
vars->count++;
if (!vars->count)
vars->count--;
cobalt_invsqrt(vars);
vars->drop_next = cobalt_control(vars->drop_next,
p->interval,
vars->rec_inv_sqrt);
schedule = ktime_sub(now, vars->drop_next);
} else {
while (next_due) {
vars->count--;
cobalt_invsqrt(vars);
vars->drop_next = cobalt_control(vars->drop_next,
p->interval,
vars->rec_inv_sqrt);
schedule = ktime_sub(now, vars->drop_next);
next_due = vars->count && ktime_to_ns(schedule) >= 0;
}
}
/* Simple BLUE implementation. Lack of ECN is deliberate. */
if (vars->p_drop)
drop |= (prandom_u32() < vars->p_drop);
/* Overload the drop_next field as an activity timeout */
if (!vars->count)
vars->drop_next = ktime_add_ns(now, p->interval);
else if (ktime_to_ns(schedule) > 0 && !drop)
vars->drop_next = now;
return drop;
}
static void cake_update_flowkeys(struct flow_keys *keys,
const struct sk_buff *skb)
{
#if IS_ENABLED(CONFIG_NF_CONNTRACK)
struct nf_conntrack_tuple tuple = {};
bool rev = !skb->_nfct;
if (skb_protocol(skb, true) != htons(ETH_P_IP))
return;
if (!nf_ct_get_tuple_skb(&tuple, skb))
return;
keys->addrs.v4addrs.src = rev ? tuple.dst.u3.ip : tuple.src.u3.ip;
keys->addrs.v4addrs.dst = rev ? tuple.src.u3.ip : tuple.dst.u3.ip;
if (keys->ports.ports) {
keys->ports.src = rev ? tuple.dst.u.all : tuple.src.u.all;
keys->ports.dst = rev ? tuple.src.u.all : tuple.dst.u.all;
}
#endif
}
/* Cake has several subtle multiple bit settings. In these cases you
* would be matching triple isolate mode as well.
*/
static bool cake_dsrc(int flow_mode)
{
return (flow_mode & CAKE_FLOW_DUAL_SRC) == CAKE_FLOW_DUAL_SRC;
}
static bool cake_ddst(int flow_mode)
{
return (flow_mode & CAKE_FLOW_DUAL_DST) == CAKE_FLOW_DUAL_DST;
}
static u32 cake_hash(struct cake_tin_data *q, const struct sk_buff *skb,
int flow_mode, u16 flow_override, u16 host_override)
{
u32 flow_hash = 0, srchost_hash = 0, dsthost_hash = 0;
u16 reduced_hash, srchost_idx, dsthost_idx;
struct flow_keys keys, host_keys;
if (unlikely(flow_mode == CAKE_FLOW_NONE))
return 0;
/* If both overrides are set we can skip packet dissection entirely */
if ((flow_override || !(flow_mode & CAKE_FLOW_FLOWS)) &&
(host_override || !(flow_mode & CAKE_FLOW_HOSTS)))
goto skip_hash;
skb_flow_dissect_flow_keys(skb, &keys,
FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL);
if (flow_mode & CAKE_FLOW_NAT_FLAG)
cake_update_flowkeys(&keys, skb);
/* flow_hash_from_keys() sorts the addresses by value, so we have
* to preserve their order in a separate data structure to treat
* src and dst host addresses as independently selectable.
*/
host_keys = keys;
host_keys.ports.ports = 0;
host_keys.basic.ip_proto = 0;
host_keys.keyid.keyid = 0;
host_keys.tags.flow_label = 0;
switch (host_keys.control.addr_type) {
case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
host_keys.addrs.v4addrs.src = 0;
dsthost_hash = flow_hash_from_keys(&host_keys);
host_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
host_keys.addrs.v4addrs.dst = 0;
srchost_hash = flow_hash_from_keys(&host_keys);
break;
case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
memset(&host_keys.addrs.v6addrs.src, 0,
sizeof(host_keys.addrs.v6addrs.src));
dsthost_hash = flow_hash_from_keys(&host_keys);
host_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src;
memset(&host_keys.addrs.v6addrs.dst, 0,
sizeof(host_keys.addrs.v6addrs.dst));
srchost_hash = flow_hash_from_keys(&host_keys);
break;
default:
dsthost_hash = 0;
srchost_hash = 0;
}
/* This *must* be after the above switch, since as a
* side-effect it sorts the src and dst addresses.
*/
if (flow_mode & CAKE_FLOW_FLOWS)
flow_hash = flow_hash_from_keys(&keys);
skip_hash:
if (flow_override)
flow_hash = flow_override - 1;
if (host_override) {
dsthost_hash = host_override - 1;
srchost_hash = host_override - 1;
}
if (!(flow_mode & CAKE_FLOW_FLOWS)) {
if (flow_mode & CAKE_FLOW_SRC_IP)
flow_hash ^= srchost_hash;
if (flow_mode & CAKE_FLOW_DST_IP)
flow_hash ^= dsthost_hash;
}
reduced_hash = flow_hash % CAKE_QUEUES;
/* set-associative hashing */
/* fast path if no hash collision (direct lookup succeeds) */
if (likely(q->tags[reduced_hash] == flow_hash &&
q->flows[reduced_hash].set)) {
q->way_directs++;
} else {
u32 inner_hash = reduced_hash % CAKE_SET_WAYS;
u32 outer_hash = reduced_hash - inner_hash;
bool allocate_src = false;
bool allocate_dst = false;
u32 i, k;
/* check if any active queue in the set is reserved for
* this flow.
*/
for (i = 0, k = inner_hash; i < CAKE_SET_WAYS;
i++, k = (k + 1) % CAKE_SET_WAYS) {
if (q->tags[outer_hash + k] == flow_hash) {
if (i)
q->way_hits++;
if (!q->flows[outer_hash + k].set) {
/* need to increment host refcnts */
allocate_src = cake_dsrc(flow_mode);
allocate_dst = cake_ddst(flow_mode);
}
goto found;
}
}
/* no queue is reserved for this flow, look for an
* empty one.
*/
for (i = 0; i < CAKE_SET_WAYS;
i++, k = (k + 1) % CAKE_SET_WAYS) {
if (!q->flows[outer_hash + k].set) {
q->way_misses++;
allocate_src = cake_dsrc(flow_mode);
allocate_dst = cake_ddst(flow_mode);
goto found;
}
}
/* With no empty queues, default to the original
* queue, accept the collision, update the host tags.
*/
q->way_collisions++;
q->hosts[q->flows[reduced_hash].srchost].srchost_refcnt--;
q->hosts[q->flows[reduced_hash].dsthost].dsthost_refcnt--;
allocate_src = cake_dsrc(flow_mode);
allocate_dst = cake_ddst(flow_mode);
found:
/* reserve queue for future packets in same flow */
reduced_hash = outer_hash + k;
q->tags[reduced_hash] = flow_hash;
if (allocate_src) {
srchost_idx = srchost_hash % CAKE_QUEUES;
inner_hash = srchost_idx % CAKE_SET_WAYS;
outer_hash = srchost_idx - inner_hash;
for (i = 0, k = inner_hash; i < CAKE_SET_WAYS;
i++, k = (k + 1) % CAKE_SET_WAYS) {
if (q->hosts[outer_hash + k].srchost_tag ==
srchost_hash)
goto found_src;
}
for (i = 0; i < CAKE_SET_WAYS;
i++, k = (k + 1) % CAKE_SET_WAYS) {
if (!q->hosts[outer_hash + k].srchost_refcnt)
break;
}
q->hosts[outer_hash + k].srchost_tag = srchost_hash;
found_src:
srchost_idx = outer_hash + k;
q->hosts[srchost_idx].srchost_refcnt++;
q->flows[reduced_hash].srchost = srchost_idx;
}
if (allocate_dst) {
dsthost_idx = dsthost_hash % CAKE_QUEUES;
inner_hash = dsthost_idx % CAKE_SET_WAYS;
outer_hash = dsthost_idx - inner_hash;
for (i = 0, k = inner_hash; i < CAKE_SET_WAYS;
i++, k = (k + 1) % CAKE_SET_WAYS) {
if (q->hosts[outer_hash + k].dsthost_tag ==
dsthost_hash)
goto found_dst;
}
for (i = 0; i < CAKE_SET_WAYS;
i++, k = (k + 1) % CAKE_SET_WAYS) {
if (!q->hosts[outer_hash + k].dsthost_refcnt)
break;
}
q->hosts[outer_hash + k].dsthost_tag = dsthost_hash;
found_dst:
dsthost_idx = outer_hash + k;
q->hosts[dsthost_idx].dsthost_refcnt++;
q->flows[reduced_hash].dsthost = dsthost_idx;
}
}
return reduced_hash;
}
/* helper functions : might be changed when/if skb use a standard list_head */
/* remove one skb from head of slot queue */
static struct sk_buff *dequeue_head(struct cake_flow *flow)
{
struct sk_buff *skb = flow->head;
if (skb) {
flow->head = skb->next;
skb->next = NULL;
}
return skb;
}
/* add skb to flow queue (tail add) */
static void flow_queue_add(struct cake_flow *flow, struct sk_buff *skb)
{
if (!flow->head)
flow->head = skb;
else
flow->tail->next = skb;
flow->tail = skb;
skb->next = NULL;
}
static struct iphdr *cake_get_iphdr(const struct sk_buff *skb,
struct ipv6hdr *buf)
{
unsigned int offset = skb_network_offset(skb);
struct iphdr *iph;
iph = skb_header_pointer(skb, offset, sizeof(struct iphdr), buf);
if (!iph)
return NULL;
if (iph->version == 4 && iph->protocol == IPPROTO_IPV6)
return skb_header_pointer(skb, offset + iph->ihl * 4,
sizeof(struct ipv6hdr), buf);
else if (iph->version == 4)
return iph;
else if (iph->version == 6)
return skb_header_pointer(skb, offset, sizeof(struct ipv6hdr),
buf);
return NULL;
}
static struct tcphdr *cake_get_tcphdr(const struct sk_buff *skb,
void *buf, unsigned int bufsize)
{
unsigned int offset = skb_network_offset(skb);
const struct ipv6hdr *ipv6h;
const struct tcphdr *tcph;
const struct iphdr *iph;
struct ipv6hdr _ipv6h;
struct tcphdr _tcph;
ipv6h = skb_header_pointer(skb, offset, sizeof(_ipv6h), &_ipv6h);
if (!ipv6h)
return NULL;
if (ipv6h->version == 4) {
iph = (struct iphdr *)ipv6h;
offset += iph->ihl * 4;
/* special-case 6in4 tunnelling, as that is a common way to get
* v6 connectivity in the home
*/
if (iph->protocol == IPPROTO_IPV6) {
ipv6h = skb_header_pointer(skb, offset,
sizeof(_ipv6h), &_ipv6h);
if (!ipv6h || ipv6h->nexthdr != IPPROTO_TCP)
return NULL;
offset += sizeof(struct ipv6hdr);
} else if (iph->protocol != IPPROTO_TCP) {
return NULL;
}
} else if (ipv6h->version == 6) {
if (ipv6h->nexthdr != IPPROTO_TCP)
return NULL;
offset += sizeof(struct ipv6hdr);
} else {
return NULL;
}
tcph = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph);
if (!tcph || tcph->doff < 5)
return NULL;
return skb_header_pointer(skb, offset,
min(__tcp_hdrlen(tcph), bufsize), buf);
}
static const void *cake_get_tcpopt(const struct tcphdr *tcph,
int code, int *oplen)
{
/* inspired by tcp_parse_options in tcp_input.c */
int length = __tcp_hdrlen(tcph) - sizeof(struct tcphdr);
const u8 *ptr = (const u8 *)(tcph + 1);
while (length > 0) {
int opcode = *ptr++;
int opsize;
if (opcode == TCPOPT_EOL)
break;
if (opcode == TCPOPT_NOP) {
length--;
continue;
}
if (length < 2)
break;
opsize = *ptr++;
if (opsize < 2 || opsize > length)
break;
if (opcode == code) {
*oplen = opsize;
return ptr;
}
ptr += opsize - 2;
length -= opsize;
}
return NULL;
}
/* Compare two SACK sequences. A sequence is considered greater if it SACKs more
* bytes than the other. In the case where both sequences ACKs bytes that the
* other doesn't, A is considered greater. DSACKs in A also makes A be
* considered greater.
*
* @return -1, 0 or 1 as normal compare functions
*/
static int cake_tcph_sack_compare(const struct tcphdr *tcph_a,
const struct tcphdr *tcph_b)
{
const struct tcp_sack_block_wire *sack_a, *sack_b;
u32 ack_seq_a = ntohl(tcph_a->ack_seq);
u32 bytes_a = 0, bytes_b = 0;
int oplen_a, oplen_b;
bool first = true;
sack_a = cake_get_tcpopt(tcph_a, TCPOPT_SACK, &oplen_a);
sack_b = cake_get_tcpopt(tcph_b, TCPOPT_SACK, &oplen_b);
/* pointers point to option contents */
oplen_a -= TCPOLEN_SACK_BASE;
oplen_b -= TCPOLEN_SACK_BASE;
if (sack_a && oplen_a >= sizeof(*sack_a) &&
(!sack_b || oplen_b < sizeof(*sack_b)))
return -1;
else if (sack_b && oplen_b >= sizeof(*sack_b) &&
(!sack_a || oplen_a < sizeof(*sack_a)))
return 1;
else if ((!sack_a || oplen_a < sizeof(*sack_a)) &&
(!sack_b || oplen_b < sizeof(*sack_b)))
return 0;
while (oplen_a >= sizeof(*sack_a)) {
const struct tcp_sack_block_wire *sack_tmp = sack_b;
u32 start_a = get_unaligned_be32(&sack_a->start_seq);
u32 end_a = get_unaligned_be32(&sack_a->end_seq);
int oplen_tmp = oplen_b;
bool found = false;
/* DSACK; always considered greater to prevent dropping */
if (before(start_a, ack_seq_a))
return -1;
bytes_a += end_a - start_a;
while (oplen_tmp >= sizeof(*sack_tmp)) {
u32 start_b = get_unaligned_be32(&sack_tmp->start_seq);
u32 end_b = get_unaligned_be32(&sack_tmp->end_seq);
/* first time through we count the total size */
if (first)
bytes_b += end_b - start_b;
if (!after(start_b, start_a) && !before(end_b, end_a)) {
found = true;
if (!first)
break;
}
oplen_tmp -= sizeof(*sack_tmp);
sack_tmp++;
}
if (!found)
return -1;
oplen_a -= sizeof(*sack_a);
sack_a++;
first = false;
}
/* If we made it this far, all ranges SACKed by A are covered by B, so
* either the SACKs are equal, or B SACKs more bytes.
*/
return bytes_b > bytes_a ? 1 : 0;
}
static void cake_tcph_get_tstamp(const struct tcphdr *tcph,
u32 *tsval, u32 *tsecr)
{
const u8 *ptr;
int opsize;
ptr = cake_get_tcpopt(tcph, TCPOPT_TIMESTAMP, &opsize);
if (ptr && opsize == TCPOLEN_TIMESTAMP) {
*tsval = get_unaligned_be32(ptr);
*tsecr = get_unaligned_be32(ptr + 4);
}
}
static bool cake_tcph_may_drop(const struct tcphdr *tcph,
u32 tstamp_new, u32 tsecr_new)
{
/* inspired by tcp_parse_options in tcp_input.c */
int length = __tcp_hdrlen(tcph) - sizeof(struct tcphdr);
const u8 *ptr = (const u8 *)(tcph + 1);
u32 tstamp, tsecr;
/* 3 reserved flags must be unset to avoid future breakage
* ACK must be set
* ECE/CWR are handled separately
* All other flags URG/PSH/RST/SYN/FIN must be unset
* 0x0FFF0000 = all TCP flags (confirm ACK=1, others zero)
* 0x00C00000 = CWR/ECE (handled separately)
* 0x0F3F0000 = 0x0FFF0000 & ~0x00C00000
*/
if (((tcp_flag_word(tcph) &
cpu_to_be32(0x0F3F0000)) != TCP_FLAG_ACK))
return false;
while (length > 0) {
int opcode = *ptr++;
int opsize;
if (opcode == TCPOPT_EOL)
break;
if (opcode == TCPOPT_NOP) {
length--;
continue;
}
if (length < 2)
break;
opsize = *ptr++;
if (opsize < 2 || opsize > length)
break;
switch (opcode) {
case TCPOPT_MD5SIG: /* doesn't influence state */
break;
case TCPOPT_SACK: /* stricter checking performed later */
if (opsize % 8 != 2)
return false;
break;
case TCPOPT_TIMESTAMP:
/* only drop timestamps lower than new */
if (opsize != TCPOLEN_TIMESTAMP)
return false;
tstamp = get_unaligned_be32(ptr);
tsecr = get_unaligned_be32(ptr + 4);
if (after(tstamp, tstamp_new) ||
after(tsecr, tsecr_new))
return false;
break;
case TCPOPT_MSS: /* these should only be set on SYN */
case TCPOPT_WINDOW:
case TCPOPT_SACK_PERM:
case TCPOPT_FASTOPEN:
case TCPOPT_EXP:
default: /* don't drop if any unknown options are present */
return false;
}
ptr += opsize - 2;
length -= opsize;
}
return true;
}
static struct sk_buff *cake_ack_filter(struct cake_sched_data *q,
struct cake_flow *flow)
{
bool aggressive = q->ack_filter == CAKE_ACK_AGGRESSIVE;
struct sk_buff *elig_ack = NULL, *elig_ack_prev = NULL;
struct sk_buff *skb_check, *skb_prev = NULL;
const struct ipv6hdr *ipv6h, *ipv6h_check;
unsigned char _tcph[64], _tcph_check[64];
const struct tcphdr *tcph, *tcph_check;
const struct iphdr *iph, *iph_check;
struct ipv6hdr _iph, _iph_check;
const struct sk_buff *skb;
int seglen, num_found = 0;
u32 tstamp = 0, tsecr = 0;
__be32 elig_flags = 0;
int sack_comp;
/* no other possible ACKs to filter */
if (flow->head == flow->tail)
return NULL;
skb = flow->tail;
tcph = cake_get_tcphdr(skb, _tcph, sizeof(_tcph));
iph = cake_get_iphdr(skb, &_iph);
if (!tcph)
return NULL;
cake_tcph_get_tstamp(tcph, &tstamp, &tsecr);
/* the 'triggering' packet need only have the ACK flag set.
* also check that SYN is not set, as there won't be any previous ACKs.
*/
if ((tcp_flag_word(tcph) &
(TCP_FLAG_ACK | TCP_FLAG_SYN)) != TCP_FLAG_ACK)
return NULL;
/* the 'triggering' ACK is at the tail of the queue, we have already
* returned if it is the only packet in the flow. loop through the rest
* of the queue looking for pure ACKs with the same 5-tuple as the
* triggering one.
*/
for (skb_check = flow->head;
skb_check && skb_check != skb;
skb_prev = skb_check, skb_check = skb_check->next) {
iph_check = cake_get_iphdr(skb_check, &_iph_check);
tcph_check = cake_get_tcphdr(skb_check, &_tcph_check,
sizeof(_tcph_check));
/* only TCP packets with matching 5-tuple are eligible, and only
* drop safe headers
*/
if (!tcph_check || iph->version != iph_check->version ||
tcph_check->source != tcph->source ||
tcph_check->dest != tcph->dest)
continue;
if (iph_check->version == 4) {
if (iph_check->saddr != iph->saddr ||
iph_check->daddr != iph->daddr)
continue;
seglen = ntohs(iph_check->tot_len) -
(4 * iph_check->ihl);
} else if (iph_check->version == 6) {
ipv6h = (struct ipv6hdr *)iph;
ipv6h_check = (struct ipv6hdr *)iph_check;
if (ipv6_addr_cmp(&ipv6h_check->saddr, &ipv6h->saddr) ||
ipv6_addr_cmp(&ipv6h_check->daddr, &ipv6h->daddr))
continue;
seglen = ntohs(ipv6h_check->payload_len);
} else {
WARN_ON(1); /* shouldn't happen */
continue;
}
/* If the ECE/CWR flags changed from the previous eligible
* packet in the same flow, we should no longer be dropping that
* previous packet as this would lose information.
*/
if (elig_ack && (tcp_flag_word(tcph_check) &
(TCP_FLAG_ECE | TCP_FLAG_CWR)) != elig_flags) {
elig_ack = NULL;
elig_ack_prev = NULL;
num_found--;
}
/* Check TCP options and flags, don't drop ACKs with segment
* data, and don't drop ACKs with a higher cumulative ACK
* counter than the triggering packet. Check ACK seqno here to
* avoid parsing SACK options of packets we are going to exclude
* anyway.
*/
if (!cake_tcph_may_drop(tcph_check, tstamp, tsecr) ||
(seglen - __tcp_hdrlen(tcph_check)) != 0 ||
after(ntohl(tcph_check->ack_seq), ntohl(tcph->ack_seq)))
continue;
/* Check SACK options. The triggering packet must SACK more data
* than the ACK under consideration, or SACK the same range but
* have a larger cumulative ACK counter. The latter is a
* pathological case, but is contained in the following check
* anyway, just to be safe.
*/
sack_comp = cake_tcph_sack_compare(tcph_check, tcph);
if (sack_comp < 0 ||
(ntohl(tcph_check->ack_seq) == ntohl(tcph->ack_seq) &&
sack_comp == 0))
continue;
/* At this point we have found an eligible pure ACK to drop; if
* we are in aggressive mode, we are done. Otherwise, keep
* searching unless this is the second eligible ACK we
* found.
*
* Since we want to drop ACK closest to the head of the queue,
* save the first eligible ACK we find, even if we need to loop
* again.
*/
if (!elig_ack) {
elig_ack = skb_check;
elig_ack_prev = skb_prev;
elig_flags = (tcp_flag_word(tcph_check)
& (TCP_FLAG_ECE | TCP_FLAG_CWR));
}
if (num_found++ > 0)
goto found;
}
/* We made it through the queue without finding two eligible ACKs . If
* we found a single eligible ACK we can drop it in aggressive mode if
* we can guarantee that this does not interfere with ECN flag
* information. We ensure this by dropping it only if the enqueued
* packet is consecutive with the eligible ACK, and their flags match.
*/
if (elig_ack && aggressive && elig_ack->next == skb &&
(elig_flags == (tcp_flag_word(tcph) &
(TCP_FLAG_ECE | TCP_FLAG_CWR))))
goto found;
return NULL;
found:
if (elig_ack_prev)
elig_ack_prev->next = elig_ack->next;
else
flow->head = elig_ack->next;
elig_ack->next = NULL;
return elig_ack;
}
static u64 cake_ewma(u64 avg, u64 sample, u32 shift)
{
avg -= avg >> shift;
avg += sample >> shift;
return avg;
}
static u32 cake_calc_overhead(struct cake_sched_data *q, u32 len, u32 off)
{
if (q->rate_flags & CAKE_FLAG_OVERHEAD)
len -= off;
if (q->max_netlen < len)
q->max_netlen = len;
if (q->min_netlen > len)
q->min_netlen = len;
len += q->rate_overhead;
if (len < q->rate_mpu)
len = q->rate_mpu;
if (q->atm_mode == CAKE_ATM_ATM) {
len += 47;
len /= 48;
len *= 53;
} else if (q->atm_mode == CAKE_ATM_PTM) {
/* Add one byte per 64 bytes or part thereof.
* This is conservative and easier to calculate than the
* precise value.
*/
len += (len + 63) / 64;
}
if (q->max_adjlen < len)
q->max_adjlen = len;
if (q->min_adjlen > len)
q->min_adjlen = len;
return len;
}
static u32 cake_overhead(struct cake_sched_data *q, const struct sk_buff *skb)
{
const struct skb_shared_info *shinfo = skb_shinfo(skb);
unsigned int hdr_len, last_len = 0;
u32 off = skb_network_offset(skb);
u32 len = qdisc_pkt_len(skb);
u16 segs = 1;
q->avg_netoff = cake_ewma(q->avg_netoff, off << 16, 8);
if (!shinfo->gso_size)
return cake_calc_overhead(q, len, off);
/* borrowed from qdisc_pkt_len_init() */
hdr_len = skb_transport_header(skb) - skb_mac_header(skb);
/* + transport layer */
if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 |
SKB_GSO_TCPV6))) {
const struct tcphdr *th;
struct tcphdr _tcphdr;
th = skb_header_pointer(skb, skb_transport_offset(skb),
sizeof(_tcphdr), &_tcphdr);
if (likely(th))
hdr_len += __tcp_hdrlen(th);
} else {
struct udphdr _udphdr;
if (skb_header_pointer(skb, skb_transport_offset(skb),
sizeof(_udphdr), &_udphdr))
hdr_len += sizeof(struct udphdr);
}
if (unlikely(shinfo->gso_type & SKB_GSO_DODGY))
segs = DIV_ROUND_UP(skb->len - hdr_len,
shinfo->gso_size);
else
segs = shinfo->gso_segs;
len = shinfo->gso_size + hdr_len;
last_len = skb->len - shinfo->gso_size * (segs - 1);
return (cake_calc_overhead(q, len, off) * (segs - 1) +
cake_calc_overhead(q, last_len, off));
}
static void cake_heap_swap(struct cake_sched_data *q, u16 i, u16 j)
{
struct cake_heap_entry ii = q->overflow_heap[i];
struct cake_heap_entry jj = q->overflow_heap[j];
q->overflow_heap[i] = jj;
q->overflow_heap[j] = ii;
q->tins[ii.t].overflow_idx[ii.b] = j;
q->tins[jj.t].overflow_idx[jj.b] = i;
}
static u32 cake_heap_get_backlog(const struct cake_sched_data *q, u16 i)
{
struct cake_heap_entry ii = q->overflow_heap[i];
return q->tins[ii.t].backlogs[ii.b];
}
static void cake_heapify(struct cake_sched_data *q, u16 i)
{
static const u32 a = CAKE_MAX_TINS * CAKE_QUEUES;
u32 mb = cake_heap_get_backlog(q, i);
u32 m = i;
while (m < a) {
u32 l = m + m + 1;
u32 r = l + 1;
if (l < a) {
u32 lb = cake_heap_get_backlog(q, l);
if (lb > mb) {
m = l;
mb = lb;
}
}
if (r < a) {
u32 rb = cake_heap_get_backlog(q, r);
if (rb > mb) {
m = r;
mb = rb;
}
}
if (m != i) {
cake_heap_swap(q, i, m);
i = m;
} else {
break;
}
}
}
static void cake_heapify_up(struct cake_sched_data *q, u16 i)
{
while (i > 0 && i < CAKE_MAX_TINS * CAKE_QUEUES) {
u16 p = (i - 1) >> 1;
u32 ib = cake_heap_get_backlog(q, i);
u32 pb = cake_heap_get_backlog(q, p);
if (ib > pb) {
cake_heap_swap(q, i, p);
i = p;
} else {
break;
}
}
}
static int cake_advance_shaper(struct cake_sched_data *q,
struct cake_tin_data *b,
struct sk_buff *skb,
ktime_t now, bool drop)
{
u32 len = get_cobalt_cb(skb)->adjusted_len;
/* charge packet bandwidth to this tin
* and to the global shaper.
*/
if (q->rate_ns) {
u64 tin_dur = (len * b->tin_rate_ns) >> b->tin_rate_shft;
u64 global_dur = (len * q->rate_ns) >> q->rate_shft;
u64 failsafe_dur = global_dur + (global_dur >> 1);
if (ktime_before(b->time_next_packet, now))
b->time_next_packet = ktime_add_ns(b->time_next_packet,
tin_dur);
else if (ktime_before(b->time_next_packet,
ktime_add_ns(now, tin_dur)))
b->time_next_packet = ktime_add_ns(now, tin_dur);
q->time_next_packet = ktime_add_ns(q->time_next_packet,
global_dur);
if (!drop)
q->failsafe_next_packet = \
ktime_add_ns(q->failsafe_next_packet,
failsafe_dur);
}
return len;
}
static unsigned int cake_drop(struct Qdisc *sch, struct sk_buff **to_free)
{
struct cake_sched_data *q = qdisc_priv(sch);
ktime_t now = ktime_get();
u32 idx = 0, tin = 0, len;
struct cake_heap_entry qq;
struct cake_tin_data *b;
struct cake_flow *flow;
struct sk_buff *skb;
if (!q->overflow_timeout) {
int i;
/* Build fresh max-heap */
for (i = CAKE_MAX_TINS * CAKE_QUEUES / 2; i >= 0; i--)
cake_heapify(q, i);
}
q->overflow_timeout = 65535;
/* select longest queue for pruning */
qq = q->overflow_heap[0];
tin = qq.t;
idx = qq.b;
b = &q->tins[tin];
flow = &b->flows[idx];
skb = dequeue_head(flow);
if (unlikely(!skb)) {
/* heap has gone wrong, rebuild it next time */
q->overflow_timeout = 0;
return idx + (tin << 16);
}
if (cobalt_queue_full(&flow->cvars, &b->cparams, now))
b->unresponsive_flow_count++;
len = qdisc_pkt_len(skb);
q->buffer_used -= skb->truesize;
b->backlogs[idx] -= len;
b->tin_backlog -= len;
sch->qstats.backlog -= len;
qdisc_tree_reduce_backlog(sch, 1, len);
flow->dropped++;
b->tin_dropped++;
sch->qstats.drops++;
if (q->rate_flags & CAKE_FLAG_INGRESS)
cake_advance_shaper(q, b, skb, now, true);
__qdisc_drop(skb, to_free);
sch->q.qlen--;
cake_heapify(q, 0);
return idx + (tin << 16);
}
static u8 cake_handle_diffserv(struct sk_buff *skb, bool wash)
{
const int offset = skb_network_offset(skb);
u16 *buf, buf_;
u8 dscp;
switch (skb_protocol(skb, true)) {
case htons(ETH_P_IP):
buf = skb_header_pointer(skb, offset, sizeof(buf_), &buf_);
if (unlikely(!buf))
return 0;
/* ToS is in the second byte of iphdr */
dscp = ipv4_get_dsfield((struct iphdr *)buf) >> 2;
if (wash && dscp) {
const int wlen = offset + sizeof(struct iphdr);
if (!pskb_may_pull(skb, wlen) ||
skb_try_make_writable(skb, wlen))
return 0;
ipv4_change_dsfield(ip_hdr(skb), INET_ECN_MASK, 0);
}
return dscp;
case htons(ETH_P_IPV6):
buf = skb_header_pointer(skb, offset, sizeof(buf_), &buf_);
if (unlikely(!buf))
return 0;
/* Traffic class is in the first and second bytes of ipv6hdr */
dscp = ipv6_get_dsfield((struct ipv6hdr *)buf) >> 2;
if (wash && dscp) {
const int wlen = offset + sizeof(struct ipv6hdr);
if (!pskb_may_pull(skb, wlen) ||
skb_try_make_writable(skb, wlen))
return 0;
ipv6_change_dsfield(ipv6_hdr(skb), INET_ECN_MASK, 0);
}
return dscp;
case htons(ETH_P_ARP):
return 0x38; /* CS7 - Net Control */
default:
/* If there is no Diffserv field, treat as best-effort */
return 0;
}
}
static struct cake_tin_data *cake_select_tin(struct Qdisc *sch,
struct sk_buff *skb)
{
struct cake_sched_data *q = qdisc_priv(sch);
u32 tin;
bool wash;
u8 dscp;
/* Tin selection: Default to diffserv-based selection, allow overriding
* using firewall marks or skb->priority. Call DSCP parsing early if
* wash is enabled, otherwise defer to below to skip unneeded parsing.
*/
wash = !!(q->rate_flags & CAKE_FLAG_WASH);
if (wash)
dscp = cake_handle_diffserv(skb, wash);
if (q->tin_mode == CAKE_DIFFSERV_BESTEFFORT)
tin = 0;
else if (TC_H_MAJ(skb->priority) == sch->handle &&
TC_H_MIN(skb->priority) > 0 &&
TC_H_MIN(skb->priority) <= q->tin_cnt)
tin = q->tin_order[TC_H_MIN(skb->priority) - 1];
else {
if (!wash)
dscp = cake_handle_diffserv(skb, wash);
tin = q->tin_index[dscp];
if (unlikely(tin >= q->tin_cnt))
tin = 0;
}
return &q->tins[tin];
}
static u32 cake_classify(struct Qdisc *sch, struct cake_tin_data **t,
struct sk_buff *skb, int flow_mode, int *qerr)
{
struct cake_sched_data *q = qdisc_priv(sch);
struct tcf_proto *filter;
struct tcf_result res;
u16 flow = 0, host = 0;
int result;
filter = rcu_dereference_bh(q->filter_list);
if (!filter)
goto hash;
*qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
result = tcf_classify(skb, filter, &res, false);
if (result >= 0) {
#ifdef CONFIG_NET_CLS_ACT
switch (result) {
case TC_ACT_STOLEN:
case TC_ACT_QUEUED:
case TC_ACT_TRAP:
*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
/* fall through */
case TC_ACT_SHOT:
return 0;
}
#endif
if (TC_H_MIN(res.classid) <= CAKE_QUEUES)
flow = TC_H_MIN(res.classid);
if (TC_H_MAJ(res.classid) <= (CAKE_QUEUES << 16))
host = TC_H_MAJ(res.classid) >> 16;
}
hash:
*t = cake_select_tin(sch, skb);
return cake_hash(*t, skb, flow_mode, flow, host) + 1;
}
static void cake_reconfigure(struct Qdisc *sch);
static s32 cake_enqueue(struct sk_buff *skb, struct Qdisc *sch,
struct sk_buff **to_free)
{
struct cake_sched_data *q = qdisc_priv(sch);
int len = qdisc_pkt_len(skb);
int ret;
struct sk_buff *ack = NULL;
ktime_t now = ktime_get();
struct cake_tin_data *b;
struct cake_flow *flow;
u32 idx;
/* choose flow to insert into */
idx = cake_classify(sch, &b, skb, q->flow_mode, &ret);
if (idx == 0) {
if (ret & __NET_XMIT_BYPASS)
qdisc_qstats_drop(sch);
__qdisc_drop(skb, to_free);
return ret;
}
idx--;
flow = &b->flows[idx];
/* ensure shaper state isn't stale */
if (!b->tin_backlog) {
if (ktime_before(b->time_next_packet, now))
b->time_next_packet = now;
if (!sch->q.qlen) {
if (ktime_before(q->time_next_packet, now)) {
q->failsafe_next_packet = now;
q->time_next_packet = now;
} else if (ktime_after(q->time_next_packet, now) &&
ktime_after(q->failsafe_next_packet, now)) {
u64 next = \
min(ktime_to_ns(q->time_next_packet),
ktime_to_ns(
q->failsafe_next_packet));
sch->qstats.overlimits++;
qdisc_watchdog_schedule_ns(&q->watchdog, next);
}
}
}
if (unlikely(len > b->max_skblen))
b->max_skblen = len;
if (skb_is_gso(skb) && q->rate_flags & CAKE_FLAG_SPLIT_GSO) {
struct sk_buff *segs, *nskb;
netdev_features_t features = netif_skb_features(skb);
unsigned int slen = 0, numsegs = 0;
segs = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK);
if (IS_ERR_OR_NULL(segs))
return qdisc_drop(skb, sch, to_free);
while (segs) {
nskb = segs->next;
segs->next = NULL;
qdisc_skb_cb(segs)->pkt_len = segs->len;
cobalt_set_enqueue_time(segs, now);
get_cobalt_cb(segs)->adjusted_len = cake_overhead(q,
segs);
flow_queue_add(flow, segs);
sch->q.qlen++;
numsegs++;
slen += segs->len;
q->buffer_used += segs->truesize;
b->packets++;
segs = nskb;
}
/* stats */
b->bytes += slen;
b->backlogs[idx] += slen;
b->tin_backlog += slen;
sch->qstats.backlog += slen;
q->avg_window_bytes += slen;
qdisc_tree_reduce_backlog(sch, 1-numsegs, len-slen);
consume_skb(skb);
} else {
/* not splitting */
cobalt_set_enqueue_time(skb, now);
get_cobalt_cb(skb)->adjusted_len = cake_overhead(q, skb);
flow_queue_add(flow, skb);
if (q->ack_filter)
ack = cake_ack_filter(q, flow);
if (ack) {
b->ack_drops++;
sch->qstats.drops++;
b->bytes += qdisc_pkt_len(ack);
len -= qdisc_pkt_len(ack);
q->buffer_used += skb->truesize - ack->truesize;
if (q->rate_flags & CAKE_FLAG_INGRESS)
cake_advance_shaper(q, b, ack, now, true);
qdisc_tree_reduce_backlog(sch, 1, qdisc_pkt_len(ack));
consume_skb(ack);
} else {
sch->q.qlen++;
q->buffer_used += skb->truesize;
}
/* stats */
b->packets++;
b->bytes += len;
b->backlogs[idx] += len;
b->tin_backlog += len;
sch->qstats.backlog += len;
q->avg_window_bytes += len;
}
if (q->overflow_timeout)
cake_heapify_up(q, b->overflow_idx[idx]);
/* incoming bandwidth capacity estimate */
if (q->rate_flags & CAKE_FLAG_AUTORATE_INGRESS) {
u64 packet_interval = \
ktime_to_ns(ktime_sub(now, q->last_packet_time));
if (packet_interval > NSEC_PER_SEC)
packet_interval = NSEC_PER_SEC;
/* filter out short-term bursts, eg. wifi aggregation */
q->avg_packet_interval = \
cake_ewma(q->avg_packet_interval,
packet_interval,
(packet_interval > q->avg_packet_interval ?
2 : 8));
q->last_packet_time = now;
if (packet_interval > q->avg_packet_interval) {
u64 window_interval = \
ktime_to_ns(ktime_sub(now,
q->avg_window_begin));
u64 b = q->avg_window_bytes * (u64)NSEC_PER_SEC;
b = div64_u64(b, window_interval);
q->avg_peak_bandwidth =
cake_ewma(q->avg_peak_bandwidth, b,
b > q->avg_peak_bandwidth ? 2 : 8);
q->avg_window_bytes = 0;
q->avg_window_begin = now;
if (ktime_after(now,
ktime_add_ms(q->last_reconfig_time,
250))) {
q->rate_bps = (q->avg_peak_bandwidth * 15) >> 4;
cake_reconfigure(sch);
}
}
} else {
q->avg_window_bytes = 0;
q->last_packet_time = now;
}
/* flowchain */
if (!flow->set || flow->set == CAKE_SET_DECAYING) {
struct cake_host *srchost = &b->hosts[flow->srchost];
struct cake_host *dsthost = &b->hosts[flow->dsthost];
u16 host_load = 1;
if (!flow->set) {
list_add_tail(&flow->flowchain, &b->new_flows);
} else {
b->decaying_flow_count--;
list_move_tail(&flow->flowchain, &b->new_flows);
}
flow->set = CAKE_SET_SPARSE;
b->sparse_flow_count++;
if (cake_dsrc(q->flow_mode))
host_load = max(host_load, srchost->srchost_refcnt);
if (cake_ddst(q->flow_mode))
host_load = max(host_load, dsthost->dsthost_refcnt);
flow->deficit = (b->flow_quantum *
quantum_div[host_load]) >> 16;
} else if (flow->set == CAKE_SET_SPARSE_WAIT) {
/* this flow was empty, accounted as a sparse flow, but actually
* in the bulk rotation.
*/
flow->set = CAKE_SET_BULK;
b->sparse_flow_count--;
b->bulk_flow_count++;
}
if (q->buffer_used > q->buffer_max_used)
q->buffer_max_used = q->buffer_used;
if (q->buffer_used > q->buffer_limit) {
u32 dropped = 0;
while (q->buffer_used > q->buffer_limit) {
dropped++;
cake_drop(sch, to_free);
}
b->drop_overlimit += dropped;
}
return NET_XMIT_SUCCESS;
}
static struct sk_buff *cake_dequeue_one(struct Qdisc *sch)
{
struct cake_sched_data *q = qdisc_priv(sch);
struct cake_tin_data *b = &q->tins[q->cur_tin];
struct cake_flow *flow = &b->flows[q->cur_flow];
struct sk_buff *skb = NULL;
u32 len;
if (flow->head) {
skb = dequeue_head(flow);
len = qdisc_pkt_len(skb);
b->backlogs[q->cur_flow] -= len;
b->tin_backlog -= len;
sch->qstats.backlog -= len;
q->buffer_used -= skb->truesize;
sch->q.qlen--;
if (q->overflow_timeout)
cake_heapify(q, b->overflow_idx[q->cur_flow]);
}
return skb;
}
/* Discard leftover packets from a tin no longer in use. */
static void cake_clear_tin(struct Qdisc *sch, u16 tin)
{
struct cake_sched_data *q = qdisc_priv(sch);
struct sk_buff *skb;
q->cur_tin = tin;
for (q->cur_flow = 0; q->cur_flow < CAKE_QUEUES; q->cur_flow++)
while (!!(skb = cake_dequeue_one(sch)))
kfree_skb(skb);
}
static struct sk_buff *cake_dequeue(struct Qdisc *sch)
{
struct cake_sched_data *q = qdisc_priv(sch);
struct cake_tin_data *b = &q->tins[q->cur_tin];
struct cake_host *srchost, *dsthost;
ktime_t now = ktime_get();
struct cake_flow *flow;
struct list_head *head;
bool first_flow = true;
struct sk_buff *skb;
u16 host_load;
u64 delay;
u32 len;
begin:
if (!sch->q.qlen)
return NULL;
/* global hard shaper */
if (ktime_after(q->time_next_packet, now) &&
ktime_after(q->failsafe_next_packet, now)) {
u64 next = min(ktime_to_ns(q->time_next_packet),
ktime_to_ns(q->failsafe_next_packet));
sch->qstats.overlimits++;
qdisc_watchdog_schedule_ns(&q->watchdog, next);
return NULL;
}
/* Choose a class to work on. */
if (!q->rate_ns) {
/* In unlimited mode, can't rely on shaper timings, just balance
* with DRR
*/
bool wrapped = false, empty = true;
while (b->tin_deficit < 0 ||
!(b->sparse_flow_count + b->bulk_flow_count)) {
if (b->tin_deficit <= 0)
b->tin_deficit += b->tin_quantum_band;
if (b->sparse_flow_count + b->bulk_flow_count)
empty = false;
q->cur_tin++;
b++;
if (q->cur_tin >= q->tin_cnt) {
q->cur_tin = 0;
b = q->tins;
if (wrapped) {
/* It's possible for q->qlen to be
* nonzero when we actually have no
* packets anywhere.
*/
if (empty)
return NULL;
} else {
wrapped = true;
}
}
}
} else {
/* In shaped mode, choose:
* - Highest-priority tin with queue and meeting schedule, or
* - The earliest-scheduled tin with queue.
*/
ktime_t best_time = KTIME_MAX;
int tin, best_tin = 0;
for (tin = 0; tin < q->tin_cnt; tin++) {
b = q->tins + tin;
if ((b->sparse_flow_count + b->bulk_flow_count) > 0) {
ktime_t time_to_pkt = \
ktime_sub(b->time_next_packet, now);
if (ktime_to_ns(time_to_pkt) <= 0 ||
ktime_compare(time_to_pkt,
best_time) <= 0) {
best_time = time_to_pkt;
best_tin = tin;
}
}
}
q->cur_tin = best_tin;
b = q->tins + best_tin;
/* No point in going further if no packets to deliver. */
if (unlikely(!(b->sparse_flow_count + b->bulk_flow_count)))
return NULL;
}
retry:
/* service this class */
head = &b->decaying_flows;
if (!first_flow || list_empty(head)) {
head = &b->new_flows;
if (list_empty(head)) {
head = &b->old_flows;
if (unlikely(list_empty(head))) {
head = &b->decaying_flows;
if (unlikely(list_empty(head)))
goto begin;
}
}
}
flow = list_first_entry(head, struct cake_flow, flowchain);
q->cur_flow = flow - b->flows;
first_flow = false;
/* triple isolation (modified DRR++) */
srchost = &b->hosts[flow->srchost];
dsthost = &b->hosts[flow->dsthost];
host_load = 1;
if (cake_dsrc(q->flow_mode))
host_load = max(host_load, srchost->srchost_refcnt);
if (cake_ddst(q->flow_mode))
host_load = max(host_load, dsthost->dsthost_refcnt);
WARN_ON(host_load > CAKE_QUEUES);
/* flow isolation (DRR++) */
if (flow->deficit <= 0) {
/* The shifted prandom_u32() is a way to apply dithering to
* avoid accumulating roundoff errors
*/
flow->deficit += (b->flow_quantum * quantum_div[host_load] +
(prandom_u32() >> 16)) >> 16;
list_move_tail(&flow->flowchain, &b->old_flows);
/* Keep all flows with deficits out of the sparse and decaying
* rotations. No non-empty flow can go into the decaying
* rotation, so they can't get deficits
*/
if (flow->set == CAKE_SET_SPARSE) {
if (flow->head) {
b->sparse_flow_count--;
b->bulk_flow_count++;
flow->set = CAKE_SET_BULK;
} else {
/* we've moved it to the bulk rotation for
* correct deficit accounting but we still want
* to count it as a sparse flow, not a bulk one.
*/
flow->set = CAKE_SET_SPARSE_WAIT;
}
}
goto retry;
}
/* Retrieve a packet via the AQM */
while (1) {
skb = cake_dequeue_one(sch);
if (!skb) {
/* this queue was actually empty */
if (cobalt_queue_empty(&flow->cvars, &b->cparams, now))
b->unresponsive_flow_count--;
if (flow->cvars.p_drop || flow->cvars.count ||
ktime_before(now, flow->cvars.drop_next)) {
/* keep in the flowchain until the state has
* decayed to rest
*/
list_move_tail(&flow->flowchain,
&b->decaying_flows);
if (flow->set == CAKE_SET_BULK) {
b->bulk_flow_count--;
b->decaying_flow_count++;
} else if (flow->set == CAKE_SET_SPARSE ||
flow->set == CAKE_SET_SPARSE_WAIT) {
b->sparse_flow_count--;
b->decaying_flow_count++;
}
flow->set = CAKE_SET_DECAYING;
} else {
/* remove empty queue from the flowchain */
list_del_init(&flow->flowchain);
if (flow->set == CAKE_SET_SPARSE ||
flow->set == CAKE_SET_SPARSE_WAIT)
b->sparse_flow_count--;
else if (flow->set == CAKE_SET_BULK)
b->bulk_flow_count--;
else
b->decaying_flow_count--;
flow->set = CAKE_SET_NONE;
srchost->srchost_refcnt--;
dsthost->dsthost_refcnt--;
}
goto begin;
}
/* Last packet in queue may be marked, shouldn't be dropped */
if (!cobalt_should_drop(&flow->cvars, &b->cparams, now, skb,
(b->bulk_flow_count *
!!(q->rate_flags &
CAKE_FLAG_INGRESS))) ||
!flow->head)
break;
/* drop this packet, get another one */
if (q->rate_flags & CAKE_FLAG_INGRESS) {
len = cake_advance_shaper(q, b, skb,
now, true);
flow->deficit -= len;
b->tin_deficit -= len;
}
flow->dropped++;
b->tin_dropped++;
qdisc_tree_reduce_backlog(sch, 1, qdisc_pkt_len(skb));
qdisc_qstats_drop(sch);
kfree_skb(skb);
if (q->rate_flags & CAKE_FLAG_INGRESS)
goto retry;
}
b->tin_ecn_mark += !!flow->cvars.ecn_marked;
qdisc_bstats_update(sch, skb);
/* collect delay stats */
delay = ktime_to_ns(ktime_sub(now, cobalt_get_enqueue_time(skb)));
b->avge_delay = cake_ewma(b->avge_delay, delay, 8);
b->peak_delay = cake_ewma(b->peak_delay, delay,
delay > b->peak_delay ? 2 : 8);
b->base_delay = cake_ewma(b->base_delay, delay,
delay < b->base_delay ? 2 : 8);
len = cake_advance_shaper(q, b, skb, now, false);
flow->deficit -= len;
b->tin_deficit -= len;
if (ktime_after(q->time_next_packet, now) && sch->q.qlen) {
u64 next = min(ktime_to_ns(q->time_next_packet),
ktime_to_ns(q->failsafe_next_packet));
qdisc_watchdog_schedule_ns(&q->watchdog, next);
} else if (!sch->q.qlen) {
int i;
for (i = 0; i < q->tin_cnt; i++) {
if (q->tins[i].decaying_flow_count) {
ktime_t next = \
ktime_add_ns(now,
q->tins[i].cparams.target);
qdisc_watchdog_schedule_ns(&q->watchdog,
ktime_to_ns(next));
break;
}
}
}
if (q->overflow_timeout)
q->overflow_timeout--;
return skb;
}
static void cake_reset(struct Qdisc *sch)
{
struct cake_sched_data *q = qdisc_priv(sch);
u32 c;
if (!q->tins)
return;
for (c = 0; c < CAKE_MAX_TINS; c++)
cake_clear_tin(sch, c);
}
static const struct nla_policy cake_policy[TCA_CAKE_MAX + 1] = {
[TCA_CAKE_BASE_RATE64] = { .type = NLA_U64 },
[TCA_CAKE_DIFFSERV_MODE] = { .type = NLA_U32 },
[TCA_CAKE_ATM] = { .type = NLA_U32 },
[TCA_CAKE_FLOW_MODE] = { .type = NLA_U32 },
[TCA_CAKE_OVERHEAD] = { .type = NLA_S32 },
[TCA_CAKE_RTT] = { .type = NLA_U32 },
[TCA_CAKE_TARGET] = { .type = NLA_U32 },
[TCA_CAKE_AUTORATE] = { .type = NLA_U32 },
[TCA_CAKE_MEMORY] = { .type = NLA_U32 },
[TCA_CAKE_NAT] = { .type = NLA_U32 },
[TCA_CAKE_RAW] = { .type = NLA_U32 },
[TCA_CAKE_WASH] = { .type = NLA_U32 },
[TCA_CAKE_MPU] = { .type = NLA_U32 },
[TCA_CAKE_INGRESS] = { .type = NLA_U32 },
[TCA_CAKE_ACK_FILTER] = { .type = NLA_U32 },
};
static void cake_set_rate(struct cake_tin_data *b, u64 rate, u32 mtu,
u64 target_ns, u64 rtt_est_ns)
{
/* convert byte-rate into time-per-byte
* so it will always unwedge in reasonable time.
*/
static const u64 MIN_RATE = 64;
u32 byte_target = mtu;
u64 byte_target_ns;
u8 rate_shft = 0;
u64 rate_ns = 0;
b->flow_quantum = 1514;
if (rate) {
b->flow_quantum = max(min(rate >> 12, 1514ULL), 300ULL);
rate_shft = 34;
rate_ns = ((u64)NSEC_PER_SEC) << rate_shft;
rate_ns = div64_u64(rate_ns, max(MIN_RATE, rate));
while (!!(rate_ns >> 34)) {
rate_ns >>= 1;
rate_shft--;
}
} /* else unlimited, ie. zero delay */
b->tin_rate_bps = rate;
b->tin_rate_ns = rate_ns;
b->tin_rate_shft = rate_shft;
byte_target_ns = (byte_target * rate_ns) >> rate_shft;
b->cparams.target = max((byte_target_ns * 3) / 2, target_ns);
b->cparams.interval = max(rtt_est_ns +
b->cparams.target - target_ns,
b->cparams.target * 2);
b->cparams.mtu_time = byte_target_ns;
b->cparams.p_inc = 1 << 24; /* 1/256 */
b->cparams.p_dec = 1 << 20; /* 1/4096 */
}
static int cake_config_besteffort(struct Qdisc *sch)
{
struct cake_sched_data *q = qdisc_priv(sch);
struct cake_tin_data *b = &q->tins[0];
u32 mtu = psched_mtu(qdisc_dev(sch));
u64 rate = q->rate_bps;
q->tin_cnt = 1;
q->tin_index = besteffort;
q->tin_order = normal_order;
cake_set_rate(b, rate, mtu,
us_to_ns(q->target), us_to_ns(q->interval));
b->tin_quantum_band = 65535;
b->tin_quantum_prio = 65535;
return 0;
}
static int cake_config_precedence(struct Qdisc *sch)
{
/* convert high-level (user visible) parameters into internal format */
struct cake_sched_data *q = qdisc_priv(sch);
u32 mtu = psched_mtu(qdisc_dev(sch));
u64 rate = q->rate_bps;
u32 quantum1 = 256;
u32 quantum2 = 256;
u32 i;
q->tin_cnt = 8;
q->tin_index = precedence;
q->tin_order = normal_order;
for (i = 0; i < q->tin_cnt; i++) {
struct cake_tin_data *b = &q->tins[i];
cake_set_rate(b, rate, mtu, us_to_ns(q->target),
us_to_ns(q->interval));
b->tin_quantum_prio = max_t(u16, 1U, quantum1);
b->tin_quantum_band = max_t(u16, 1U, quantum2);
/* calculate next class's parameters */
rate *= 7;
rate >>= 3;
quantum1 *= 3;
quantum1 >>= 1;
quantum2 *= 7;
quantum2 >>= 3;
}
return 0;
}
/* List of known Diffserv codepoints:
*
* Least Effort (CS1)
* Best Effort (CS0)
* Max Reliability & LLT "Lo" (TOS1)
* Max Throughput (TOS2)
* Min Delay (TOS4)
* LLT "La" (TOS5)
* Assured Forwarding 1 (AF1x) - x3
* Assured Forwarding 2 (AF2x) - x3
* Assured Forwarding 3 (AF3x) - x3
* Assured Forwarding 4 (AF4x) - x3
* Precedence Class 2 (CS2)
* Precedence Class 3 (CS3)
* Precedence Class 4 (CS4)
* Precedence Class 5 (CS5)
* Precedence Class 6 (CS6)
* Precedence Class 7 (CS7)
* Voice Admit (VA)
* Expedited Forwarding (EF)
* Total 25 codepoints.
*/
/* List of traffic classes in RFC 4594:
* (roughly descending order of contended priority)
* (roughly ascending order of uncontended throughput)
*
* Network Control (CS6,CS7) - routing traffic
* Telephony (EF,VA) - aka. VoIP streams
* Signalling (CS5) - VoIP setup
* Multimedia Conferencing (AF4x) - aka. video calls
* Realtime Interactive (CS4) - eg. games
* Multimedia Streaming (AF3x) - eg. YouTube, NetFlix, Twitch
* Broadcast Video (CS3)
* Low Latency Data (AF2x,TOS4) - eg. database
* Ops, Admin, Management (CS2,TOS1) - eg. ssh
* Standard Service (CS0 & unrecognised codepoints)
* High Throughput Data (AF1x,TOS2) - eg. web traffic
* Low Priority Data (CS1) - eg. BitTorrent
* Total 12 traffic classes.
*/
static int cake_config_diffserv8(struct Qdisc *sch)
{
/* Pruned list of traffic classes for typical applications:
*
* Network Control (CS6, CS7)
* Minimum Latency (EF, VA, CS5, CS4)
* Interactive Shell (CS2, TOS1)
* Low Latency Transactions (AF2x, TOS4)
* Video Streaming (AF4x, AF3x, CS3)
* Bog Standard (CS0 etc.)
* High Throughput (AF1x, TOS2)
* Background Traffic (CS1)
*
* Total 8 traffic classes.
*/
struct cake_sched_data *q = qdisc_priv(sch);
u32 mtu = psched_mtu(qdisc_dev(sch));
u64 rate = q->rate_bps;
u32 quantum1 = 256;
u32 quantum2 = 256;
u32 i;
q->tin_cnt = 8;
/* codepoint to class mapping */
q->tin_index = diffserv8;
q->tin_order = normal_order;
/* class characteristics */
for (i = 0; i < q->tin_cnt; i++) {
struct cake_tin_data *b = &q->tins[i];
cake_set_rate(b, rate, mtu, us_to_ns(q->target),
us_to_ns(q->interval));
b->tin_quantum_prio = max_t(u16, 1U, quantum1);
b->tin_quantum_band = max_t(u16, 1U, quantum2);
/* calculate next class's parameters */
rate *= 7;
rate >>= 3;
quantum1 *= 3;
quantum1 >>= 1;
quantum2 *= 7;
quantum2 >>= 3;
}
return 0;
}
static int cake_config_diffserv4(struct Qdisc *sch)
{
/* Further pruned list of traffic classes for four-class system:
*
* Latency Sensitive (CS7, CS6, EF, VA, CS5, CS4)
* Streaming Media (AF4x, AF3x, CS3, AF2x, TOS4, CS2, TOS1)
* Best Effort (CS0, AF1x, TOS2, and those not specified)
* Background Traffic (CS1)
*
* Total 4 traffic classes.
*/
struct cake_sched_data *q = qdisc_priv(sch);
u32 mtu = psched_mtu(qdisc_dev(sch));
u64 rate = q->rate_bps;
u32 quantum = 1024;
q->tin_cnt = 4;
/* codepoint to class mapping */
q->tin_index = diffserv4;
q->tin_order = bulk_order;
/* class characteristics */
cake_set_rate(&q->tins[0], rate, mtu,
us_to_ns(q->target), us_to_ns(q->interval));
cake_set_rate(&q->tins[1], rate >> 4, mtu,
us_to_ns(q->target), us_to_ns(q->interval));
cake_set_rate(&q->tins[2], rate >> 1, mtu,
us_to_ns(q->target), us_to_ns(q->interval));
cake_set_rate(&q->tins[3], rate >> 2, mtu,
us_to_ns(q->target), us_to_ns(q->interval));
/* priority weights */
q->tins[0].tin_quantum_prio = quantum;
q->tins[1].tin_quantum_prio = quantum >> 4;
q->tins[2].tin_quantum_prio = quantum << 2;
q->tins[3].tin_quantum_prio = quantum << 4;
/* bandwidth-sharing weights */
q->tins[0].tin_quantum_band = quantum;
q->tins[1].tin_quantum_band = quantum >> 4;
q->tins[2].tin_quantum_band = quantum >> 1;
q->tins[3].tin_quantum_band = quantum >> 2;
return 0;
}
static int cake_config_diffserv3(struct Qdisc *sch)
{
/* Simplified Diffserv structure with 3 tins.
* Low Priority (CS1)
* Best Effort
* Latency Sensitive (TOS4, VA, EF, CS6, CS7)
*/
struct cake_sched_data *q = qdisc_priv(sch);
u32 mtu = psched_mtu(qdisc_dev(sch));
u64 rate = q->rate_bps;
u32 quantum = 1024;
q->tin_cnt = 3;
/* codepoint to class mapping */
q->tin_index = diffserv3;
q->tin_order = bulk_order;
/* class characteristics */
cake_set_rate(&q->tins[0], rate, mtu,
us_to_ns(q->target), us_to_ns(q->interval));
cake_set_rate(&q->tins[1], rate >> 4, mtu,
us_to_ns(q->target), us_to_ns(q->interval));
cake_set_rate(&q->tins[2], rate >> 2, mtu,
us_to_ns(q->target), us_to_ns(q->interval));
/* priority weights */
q->tins[0].tin_quantum_prio = quantum;
q->tins[1].tin_quantum_prio = quantum >> 4;
q->tins[2].tin_quantum_prio = quantum << 4;
/* bandwidth-sharing weights */
q->tins[0].tin_quantum_band = quantum;
q->tins[1].tin_quantum_band = quantum >> 4;
q->tins[2].tin_quantum_band = quantum >> 2;
return 0;
}
static void cake_reconfigure(struct Qdisc *sch)
{
struct cake_sched_data *q = qdisc_priv(sch);
int c, ft;
switch (q->tin_mode) {
case CAKE_DIFFSERV_BESTEFFORT:
ft = cake_config_besteffort(sch);
break;
case CAKE_DIFFSERV_PRECEDENCE:
ft = cake_config_precedence(sch);
break;
case CAKE_DIFFSERV_DIFFSERV8:
ft = cake_config_diffserv8(sch);
break;
case CAKE_DIFFSERV_DIFFSERV4:
ft = cake_config_diffserv4(sch);
break;
case CAKE_DIFFSERV_DIFFSERV3:
default:
ft = cake_config_diffserv3(sch);
break;
}
for (c = q->tin_cnt; c < CAKE_MAX_TINS; c++) {
cake_clear_tin(sch, c);
q->tins[c].cparams.mtu_time = q->tins[ft].cparams.mtu_time;
}
q->rate_ns = q->tins[ft].tin_rate_ns;
q->rate_shft = q->tins[ft].tin_rate_shft;
if (q->buffer_config_limit) {
q->buffer_limit = q->buffer_config_limit;
} else if (q->rate_bps) {
u64 t = q->rate_bps * q->interval;
do_div(t, USEC_PER_SEC / 4);
q->buffer_limit = max_t(u32, t, 4U << 20);
} else {
q->buffer_limit = ~0;
}
sch->flags &= ~TCQ_F_CAN_BYPASS;
q->buffer_limit = min(q->buffer_limit,
max(sch->limit * psched_mtu(qdisc_dev(sch)),
q->buffer_config_limit));
}
static int cake_change(struct Qdisc *sch, struct nlattr *opt,
struct netlink_ext_ack *extack)
{
struct cake_sched_data *q = qdisc_priv(sch);
struct nlattr *tb[TCA_CAKE_MAX + 1];
int err;
if (!opt)
return -EINVAL;
err = nla_parse_nested(tb, TCA_CAKE_MAX, opt, cake_policy, extack);
if (err < 0)
return err;
if (tb[TCA_CAKE_NAT]) {
#if IS_ENABLED(CONFIG_NF_CONNTRACK)
q->flow_mode &= ~CAKE_FLOW_NAT_FLAG;
q->flow_mode |= CAKE_FLOW_NAT_FLAG *
!!nla_get_u32(tb[TCA_CAKE_NAT]);
#else
NL_SET_ERR_MSG_ATTR(extack, tb[TCA_CAKE_NAT],
"No conntrack support in kernel");
return -EOPNOTSUPP;
#endif
}
if (tb[TCA_CAKE_BASE_RATE64])
q->rate_bps = nla_get_u64(tb[TCA_CAKE_BASE_RATE64]);
if (tb[TCA_CAKE_DIFFSERV_MODE])
q->tin_mode = nla_get_u32(tb[TCA_CAKE_DIFFSERV_MODE]);
if (tb[TCA_CAKE_WASH]) {
if (!!nla_get_u32(tb[TCA_CAKE_WASH]))
q->rate_flags |= CAKE_FLAG_WASH;
else
q->rate_flags &= ~CAKE_FLAG_WASH;
}
if (tb[TCA_CAKE_FLOW_MODE])
q->flow_mode = ((q->flow_mode & CAKE_FLOW_NAT_FLAG) |
(nla_get_u32(tb[TCA_CAKE_FLOW_MODE]) &
CAKE_FLOW_MASK));
if (tb[TCA_CAKE_ATM])
q->atm_mode = nla_get_u32(tb[TCA_CAKE_ATM]);
if (tb[TCA_CAKE_OVERHEAD]) {
q->rate_overhead = nla_get_s32(tb[TCA_CAKE_OVERHEAD]);
q->rate_flags |= CAKE_FLAG_OVERHEAD;
q->max_netlen = 0;
q->max_adjlen = 0;
q->min_netlen = ~0;
q->min_adjlen = ~0;
}
if (tb[TCA_CAKE_RAW]) {
q->rate_flags &= ~CAKE_FLAG_OVERHEAD;
q->max_netlen = 0;
q->max_adjlen = 0;
q->min_netlen = ~0;
q->min_adjlen = ~0;
}
if (tb[TCA_CAKE_MPU])
q->rate_mpu = nla_get_u32(tb[TCA_CAKE_MPU]);
if (tb[TCA_CAKE_RTT]) {
q->interval = nla_get_u32(tb[TCA_CAKE_RTT]);
if (!q->interval)
q->interval = 1;
}
if (tb[TCA_CAKE_TARGET]) {
q->target = nla_get_u32(tb[TCA_CAKE_TARGET]);
if (!q->target)
q->target = 1;
}
if (tb[TCA_CAKE_AUTORATE]) {
if (!!nla_get_u32(tb[TCA_CAKE_AUTORATE]))
q->rate_flags |= CAKE_FLAG_AUTORATE_INGRESS;
else
q->rate_flags &= ~CAKE_FLAG_AUTORATE_INGRESS;
}
if (tb[TCA_CAKE_INGRESS]) {
if (!!nla_get_u32(tb[TCA_CAKE_INGRESS]))
q->rate_flags |= CAKE_FLAG_INGRESS;
else
q->rate_flags &= ~CAKE_FLAG_INGRESS;
}
if (tb[TCA_CAKE_ACK_FILTER])
q->ack_filter = nla_get_u32(tb[TCA_CAKE_ACK_FILTER]);
if (tb[TCA_CAKE_MEMORY])
q->buffer_config_limit = nla_get_u32(tb[TCA_CAKE_MEMORY]);
if (tb[TCA_CAKE_SPLIT_GSO]) {
if (!!nla_get_u32(tb[TCA_CAKE_SPLIT_GSO]))
q->rate_flags |= CAKE_FLAG_SPLIT_GSO;
else
q->rate_flags &= ~CAKE_FLAG_SPLIT_GSO;
}
if (q->tins) {
sch_tree_lock(sch);
cake_reconfigure(sch);
sch_tree_unlock(sch);
}
return 0;
}
static void cake_destroy(struct Qdisc *sch)
{
struct cake_sched_data *q = qdisc_priv(sch);
qdisc_watchdog_cancel(&q->watchdog);
tcf_block_put(q->block);
kvfree(q->tins);
}
static int cake_init(struct Qdisc *sch, struct nlattr *opt,
struct netlink_ext_ack *extack)
{
struct cake_sched_data *q = qdisc_priv(sch);
int i, j, err;
sch->limit = 10240;
q->tin_mode = CAKE_DIFFSERV_DIFFSERV3;
q->flow_mode = CAKE_FLOW_TRIPLE;
q->rate_bps = 0; /* unlimited by default */
q->interval = 100000; /* 100ms default */
q->target = 5000; /* 5ms: codel RFC argues
* for 5 to 10% of interval
*/
q->rate_flags |= CAKE_FLAG_SPLIT_GSO;
q->cur_tin = 0;
q->cur_flow = 0;
qdisc_watchdog_init(&q->watchdog, sch);
if (opt) {
err = cake_change(sch, opt, extack);
if (err)
return err;
}
err = tcf_block_get(&q->block, &q->filter_list, sch, extack);
if (err)
return err;
quantum_div[0] = ~0;
for (i = 1; i <= CAKE_QUEUES; i++)
quantum_div[i] = 65535 / i;
q->tins = kvcalloc(CAKE_MAX_TINS, sizeof(struct cake_tin_data),
GFP_KERNEL);
if (!q->tins)
return -ENOMEM;
for (i = 0; i < CAKE_MAX_TINS; i++) {
struct cake_tin_data *b = q->tins + i;
INIT_LIST_HEAD(&b->new_flows);
INIT_LIST_HEAD(&b->old_flows);
INIT_LIST_HEAD(&b->decaying_flows);
b->sparse_flow_count = 0;
b->bulk_flow_count = 0;
b->decaying_flow_count = 0;
for (j = 0; j < CAKE_QUEUES; j++) {
struct cake_flow *flow = b->flows + j;
u32 k = j * CAKE_MAX_TINS + i;
INIT_LIST_HEAD(&flow->flowchain);
cobalt_vars_init(&flow->cvars);
q->overflow_heap[k].t = i;
q->overflow_heap[k].b = j;
b->overflow_idx[j] = k;
}
}
cake_reconfigure(sch);
q->avg_peak_bandwidth = q->rate_bps;
q->min_netlen = ~0;
q->min_adjlen = ~0;
return 0;
}
static int cake_dump(struct Qdisc *sch, struct sk_buff *skb)
{
struct cake_sched_data *q = qdisc_priv(sch);
struct nlattr *opts;
opts = nla_nest_start(skb, TCA_OPTIONS);
if (!opts)
goto nla_put_failure;
if (nla_put_u64_64bit(skb, TCA_CAKE_BASE_RATE64, q->rate_bps,
TCA_CAKE_PAD))
goto nla_put_failure;
if (nla_put_u32(skb, TCA_CAKE_FLOW_MODE,
q->flow_mode & CAKE_FLOW_MASK))
goto nla_put_failure;
if (nla_put_u32(skb, TCA_CAKE_RTT, q->interval))
goto nla_put_failure;
if (nla_put_u32(skb, TCA_CAKE_TARGET, q->target))
goto nla_put_failure;
if (nla_put_u32(skb, TCA_CAKE_MEMORY, q->buffer_config_limit))
goto nla_put_failure;
if (nla_put_u32(skb, TCA_CAKE_AUTORATE,
!!(q->rate_flags & CAKE_FLAG_AUTORATE_INGRESS)))
goto nla_put_failure;
if (nla_put_u32(skb, TCA_CAKE_INGRESS,
!!(q->rate_flags & CAKE_FLAG_INGRESS)))
goto nla_put_failure;
if (nla_put_u32(skb, TCA_CAKE_ACK_FILTER, q->ack_filter))
goto nla_put_failure;
if (nla_put_u32(skb, TCA_CAKE_NAT,
!!(q->flow_mode & CAKE_FLOW_NAT_FLAG)))
goto nla_put_failure;
if (nla_put_u32(skb, TCA_CAKE_DIFFSERV_MODE, q->tin_mode))
goto nla_put_failure;
if (nla_put_u32(skb, TCA_CAKE_WASH,
!!(q->rate_flags & CAKE_FLAG_WASH)))
goto nla_put_failure;
if (nla_put_u32(skb, TCA_CAKE_OVERHEAD, q->rate_overhead))
goto nla_put_failure;
if (!(q->rate_flags & CAKE_FLAG_OVERHEAD))
if (nla_put_u32(skb, TCA_CAKE_RAW, 0))
goto nla_put_failure;
if (nla_put_u32(skb, TCA_CAKE_ATM, q->atm_mode))
goto nla_put_failure;
if (nla_put_u32(skb, TCA_CAKE_MPU, q->rate_mpu))
goto nla_put_failure;
if (nla_put_u32(skb, TCA_CAKE_SPLIT_GSO,
!!(q->rate_flags & CAKE_FLAG_SPLIT_GSO)))
goto nla_put_failure;
return nla_nest_end(skb, opts);
nla_put_failure:
return -1;
}
static int cake_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
{
struct nlattr *stats = nla_nest_start(d->skb, TCA_STATS_APP);
struct cake_sched_data *q = qdisc_priv(sch);
struct nlattr *tstats, *ts;
int i;
if (!stats)
return -1;
#define PUT_STAT_U32(attr, data) do { \
if (nla_put_u32(d->skb, TCA_CAKE_STATS_ ## attr, data)) \
goto nla_put_failure; \
} while (0)
#define PUT_STAT_U64(attr, data) do { \
if (nla_put_u64_64bit(d->skb, TCA_CAKE_STATS_ ## attr, \
data, TCA_CAKE_STATS_PAD)) \
goto nla_put_failure; \
} while (0)
PUT_STAT_U64(CAPACITY_ESTIMATE64, q->avg_peak_bandwidth);
PUT_STAT_U32(MEMORY_LIMIT, q->buffer_limit);
PUT_STAT_U32(MEMORY_USED, q->buffer_max_used);
PUT_STAT_U32(AVG_NETOFF, ((q->avg_netoff + 0x8000) >> 16));
PUT_STAT_U32(MAX_NETLEN, q->max_netlen);
PUT_STAT_U32(MAX_ADJLEN, q->max_adjlen);
PUT_STAT_U32(MIN_NETLEN, q->min_netlen);
PUT_STAT_U32(MIN_ADJLEN, q->min_adjlen);
#undef PUT_STAT_U32
#undef PUT_STAT_U64
tstats = nla_nest_start(d->skb, TCA_CAKE_STATS_TIN_STATS);
if (!tstats)
goto nla_put_failure;
#define PUT_TSTAT_U32(attr, data) do { \
if (nla_put_u32(d->skb, TCA_CAKE_TIN_STATS_ ## attr, data)) \
goto nla_put_failure; \
} while (0)
#define PUT_TSTAT_U64(attr, data) do { \
if (nla_put_u64_64bit(d->skb, TCA_CAKE_TIN_STATS_ ## attr, \
data, TCA_CAKE_TIN_STATS_PAD)) \
goto nla_put_failure; \
} while (0)
for (i = 0; i < q->tin_cnt; i++) {
struct cake_tin_data *b = &q->tins[q->tin_order[i]];
ts = nla_nest_start(d->skb, i + 1);
if (!ts)
goto nla_put_failure;
PUT_TSTAT_U64(THRESHOLD_RATE64, b->tin_rate_bps);
PUT_TSTAT_U64(SENT_BYTES64, b->bytes);
PUT_TSTAT_U32(BACKLOG_BYTES, b->tin_backlog);
PUT_TSTAT_U32(TARGET_US,
ktime_to_us(ns_to_ktime(b->cparams.target)));
PUT_TSTAT_U32(INTERVAL_US,
ktime_to_us(ns_to_ktime(b->cparams.interval)));
PUT_TSTAT_U32(SENT_PACKETS, b->packets);
PUT_TSTAT_U32(DROPPED_PACKETS, b->tin_dropped);
PUT_TSTAT_U32(ECN_MARKED_PACKETS, b->tin_ecn_mark);
PUT_TSTAT_U32(ACKS_DROPPED_PACKETS, b->ack_drops);
PUT_TSTAT_U32(PEAK_DELAY_US,
ktime_to_us(ns_to_ktime(b->peak_delay)));
PUT_TSTAT_U32(AVG_DELAY_US,
ktime_to_us(ns_to_ktime(b->avge_delay)));
PUT_TSTAT_U32(BASE_DELAY_US,
ktime_to_us(ns_to_ktime(b->base_delay)));
PUT_TSTAT_U32(WAY_INDIRECT_HITS, b->way_hits);
PUT_TSTAT_U32(WAY_MISSES, b->way_misses);
PUT_TSTAT_U32(WAY_COLLISIONS, b->way_collisions);
PUT_TSTAT_U32(SPARSE_FLOWS, b->sparse_flow_count +
b->decaying_flow_count);
PUT_TSTAT_U32(BULK_FLOWS, b->bulk_flow_count);
PUT_TSTAT_U32(UNRESPONSIVE_FLOWS, b->unresponsive_flow_count);
PUT_TSTAT_U32(MAX_SKBLEN, b->max_skblen);
PUT_TSTAT_U32(FLOW_QUANTUM, b->flow_quantum);
nla_nest_end(d->skb, ts);
}
#undef PUT_TSTAT_U32
#undef PUT_TSTAT_U64
nla_nest_end(d->skb, tstats);
return nla_nest_end(d->skb, stats);
nla_put_failure:
nla_nest_cancel(d->skb, stats);
return -1;
}
static struct Qdisc *cake_leaf(struct Qdisc *sch, unsigned long arg)
{
return NULL;
}
static unsigned long cake_find(struct Qdisc *sch, u32 classid)
{
return 0;
}
static unsigned long cake_bind(struct Qdisc *sch, unsigned long parent,
u32 classid)
{
return 0;
}
static void cake_unbind(struct Qdisc *q, unsigned long cl)
{
}
static struct tcf_block *cake_tcf_block(struct Qdisc *sch, unsigned long cl,
struct netlink_ext_ack *extack)
{
struct cake_sched_data *q = qdisc_priv(sch);
if (cl)
return NULL;
return q->block;
}
static int cake_dump_class(struct Qdisc *sch, unsigned long cl,
struct sk_buff *skb, struct tcmsg *tcm)
{
tcm->tcm_handle |= TC_H_MIN(cl);
return 0;
}
static int cake_dump_class_stats(struct Qdisc *sch, unsigned long cl,
struct gnet_dump *d)
{
struct cake_sched_data *q = qdisc_priv(sch);
const struct cake_flow *flow = NULL;
struct gnet_stats_queue qs = { 0 };
struct nlattr *stats;
u32 idx = cl - 1;
if (idx < CAKE_QUEUES * q->tin_cnt) {
const struct cake_tin_data *b = \
&q->tins[q->tin_order[idx / CAKE_QUEUES]];
const struct sk_buff *skb;
flow = &b->flows[idx % CAKE_QUEUES];
if (flow->head) {
sch_tree_lock(sch);
skb = flow->head;
while (skb) {
qs.qlen++;
skb = skb->next;
}
sch_tree_unlock(sch);
}
qs.backlog = b->backlogs[idx % CAKE_QUEUES];
qs.drops = flow->dropped;
}
if (gnet_stats_copy_queue(d, NULL, &qs, qs.qlen) < 0)
return -1;
if (flow) {
ktime_t now = ktime_get();
stats = nla_nest_start(d->skb, TCA_STATS_APP);
if (!stats)
return -1;
#define PUT_STAT_U32(attr, data) do { \
if (nla_put_u32(d->skb, TCA_CAKE_STATS_ ## attr, data)) \
goto nla_put_failure; \
} while (0)
#define PUT_STAT_S32(attr, data) do { \
if (nla_put_s32(d->skb, TCA_CAKE_STATS_ ## attr, data)) \
goto nla_put_failure; \
} while (0)
PUT_STAT_S32(DEFICIT, flow->deficit);
PUT_STAT_U32(DROPPING, flow->cvars.dropping);
PUT_STAT_U32(COBALT_COUNT, flow->cvars.count);
PUT_STAT_U32(P_DROP, flow->cvars.p_drop);
if (flow->cvars.p_drop) {
PUT_STAT_S32(BLUE_TIMER_US,
ktime_to_us(
ktime_sub(now,
flow->cvars.blue_timer)));
}
if (flow->cvars.dropping) {
PUT_STAT_S32(DROP_NEXT_US,
ktime_to_us(
ktime_sub(now,
flow->cvars.drop_next)));
}
if (nla_nest_end(d->skb, stats) < 0)
return -1;
}
return 0;
nla_put_failure:
nla_nest_cancel(d->skb, stats);
return -1;
}
static void cake_walk(struct Qdisc *sch, struct qdisc_walker *arg)
{
struct cake_sched_data *q = qdisc_priv(sch);
unsigned int i, j;
if (arg->stop)
return;
for (i = 0; i < q->tin_cnt; i++) {
struct cake_tin_data *b = &q->tins[q->tin_order[i]];
for (j = 0; j < CAKE_QUEUES; j++) {
if (list_empty(&b->flows[j].flowchain) ||
arg->count < arg->skip) {
arg->count++;
continue;
}
if (arg->fn(sch, i * CAKE_QUEUES + j + 1, arg) < 0) {
arg->stop = 1;
break;
}
arg->count++;
}
}
}
static const struct Qdisc_class_ops cake_class_ops = {
.leaf = cake_leaf,
.find = cake_find,
.tcf_block = cake_tcf_block,
.bind_tcf = cake_bind,
.unbind_tcf = cake_unbind,
.dump = cake_dump_class,
.dump_stats = cake_dump_class_stats,
.walk = cake_walk,
};
static struct Qdisc_ops cake_qdisc_ops __read_mostly = {
.cl_ops = &cake_class_ops,
.id = "cake",
.priv_size = sizeof(struct cake_sched_data),
.enqueue = cake_enqueue,
.dequeue = cake_dequeue,
.peek = qdisc_peek_dequeued,
.init = cake_init,
.reset = cake_reset,
.destroy = cake_destroy,
.change = cake_change,
.dump = cake_dump,
.dump_stats = cake_dump_stats,
.owner = THIS_MODULE,
};
static int __init cake_module_init(void)
{
return register_qdisc(&cake_qdisc_ops);
}
static void __exit cake_module_exit(void)
{
unregister_qdisc(&cake_qdisc_ops);
}
module_init(cake_module_init)
module_exit(cake_module_exit)
MODULE_AUTHOR("Jonathan Morton");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_DESCRIPTION("The CAKE shaper.");