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linux/net/sched/sch_cake.c
Toke Høiland-Jørgensen 93cfb6c176 sch_cake: Fix TC filter flow override and expand it to hosts as well 
The TC filter flow mapping override completely skipped the call to
cake_hash(); however that meant that the internal state was not being
updated, which ultimately leads to deadlocks in some configurations. Fix
that by passing the overridden flow ID into cake_hash() instead so it can
react appropriately.

In addition, the major number of the class ID can now be set to override
the host mapping in host isolation mode. If both host and flow are
overridden (or if the respective modes are disabled), flow dissection and
hashing will be skipped entirely; otherwise, the hashing will be kept for
the portions that are not set by the filter.

Signed-off-by: Toke Høiland-Jørgensen <toke@toke.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-22 21:39:45 -07:00

3035 lines
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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 (tc_skb_protocol(skb) != 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)
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;
}
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;
}
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 void cake_wash_diffserv(struct sk_buff *skb)
{
switch (skb->protocol) {
case htons(ETH_P_IP):
ipv4_change_dsfield(ip_hdr(skb), INET_ECN_MASK, 0);
break;
case htons(ETH_P_IPV6):
ipv6_change_dsfield(ipv6_hdr(skb), INET_ECN_MASK, 0);
break;
default:
break;
}
}
static u8 cake_handle_diffserv(struct sk_buff *skb, u16 wash)
{
u8 dscp;
switch (skb->protocol) {
case htons(ETH_P_IP):
dscp = ipv4_get_dsfield(ip_hdr(skb)) >> 2;
if (wash && dscp)
ipv4_change_dsfield(ip_hdr(skb), INET_ECN_MASK, 0);
return dscp;
case htons(ETH_P_IPV6):
dscp = ipv6_get_dsfield(ipv6_hdr(skb)) >> 2;
if (wash && dscp)
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;
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];
if (q->rate_flags & CAKE_FLAG_WASH)
cake_wash_diffserv(skb);
} else if (q->tin_mode != CAKE_DIFFSERV_BESTEFFORT) {
/* extract the Diffserv Precedence field, if it exists */
/* and clear DSCP bits if washing */
tin = q->tin_index[cake_handle_diffserv(skb,
q->rate_flags & CAKE_FLAG_WASH)];
if (unlikely(tin >= q->tin_cnt))
tin = 0;
} else {
tin = 0;
if (q->rate_flags & CAKE_FLAG_WASH)
cake_wash_diffserv(skb);
}
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 uninitialized_var(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;
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++;
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, len);
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;
do_div(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)
{
u32 c;
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) {
int 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 = kvzalloc(CAKE_MAX_TINS * sizeof(struct cake_tin_data),
GFP_KERNEL);
if (!q->tins)
goto nomem;
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;
nomem:
cake_destroy(sch);
return -ENOMEM;
}
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.");
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