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sch_cake.c
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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/version.h>
#include "pkt_sched.h"
#include <net/pkt_cls.h>
#include <linux/if_vlan.h>
#include <net/tcp.h>
#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 2, 0)
#include <net/flow_keys.h>
#else
#include <net/flow_dissector.h>
#endif
#include "cobalt_compat.h"
#if IS_REACHABLE(CONFIG_NF_CONNTRACK)
#include <net/netfilter/nf_conntrack_core.h>
#include <net/netfilter/nf_conntrack_zones.h>
#include <net/netfilter/nf_conntrack.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_bulk_flow_count;
u16 dsthost_bulk_flow_count;
};
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 */
u32 perturb;
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;
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 */
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 13, 0)
struct tcf_block *block;
#endif
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;
u32 fwmark_mask;
u16 fwmark_shft;
/* 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, 0, 1, 2, 4, 2, 2, 2,
1, 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, 1, 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, 1, 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;
}
static __be16 cake_skb_proto(const struct sk_buff *skb)
{
unsigned int offset = skb_mac_offset(skb) + sizeof(struct ethhdr);
__be16 proto = skb->protocol;
struct vlan_hdr vhdr, *vh;
while (proto == htons(ETH_P_8021Q) || proto == htons(ETH_P_8021AD)) {
vh = skb_header_pointer(skb, offset, sizeof(vhdr), &vhdr);
if (!vh)
break;
proto = vh->h_vlan_encapsulated_proto;
offset += sizeof(vhdr);
}
return proto;
}
static int cake_set_ce(struct sk_buff *skb)
{
int wlen = skb_network_offset(skb);
switch (cake_skb_proto(skb)) {
case htons(ETH_P_IP):
wlen += sizeof(struct iphdr);
if (!pskb_may_pull(skb, wlen) ||
skb_try_make_writable(skb, wlen))
return 0;
return IP_ECN_set_ce(ip_hdr(skb));
case htons(ETH_P_IPV6):
wlen += sizeof(struct ipv6hdr);
if (!pskb_may_pull(skb, wlen) ||
skb_try_make_writable(skb, wlen))
return 0;
return IP6_ECN_set_ce(skb, ipv6_hdr(skb));
default:
return 0;
}
return 0;
}
/* 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 = cake_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;
}
#if IS_REACHABLE(CONFIG_NF_CONNTRACK)
static void cake_update_flowkeys(struct flow_keys *keys,
const struct sk_buff *skb)
{
const struct nf_conntrack_tuple *tuple;
enum ip_conntrack_info ctinfo;
struct nf_conn *ct;
bool rev = false;
if (cake_skb_proto(skb) != htons(ETH_P_IP))
return;
ct = nf_ct_get(skb, &ctinfo);
if (ct) {
tuple = nf_ct_tuple(ct, CTINFO2DIR(ctinfo));
} else {
const struct nf_conntrack_tuple_hash *hash;
struct nf_conntrack_tuple srctuple;
#if KERNEL_VERSION(4, 4, 0) > LINUX_VERSION_CODE
if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb),
NFPROTO_IPV4, &srctuple))
#else
if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb),
NFPROTO_IPV4, dev_net(skb->dev),
&srctuple))
#endif
return;
#if KERNEL_VERSION(4, 3, 0) > LINUX_VERSION_CODE
hash = nf_conntrack_find_get(dev_net(skb->dev),
NF_CT_DEFAULT_ZONE,
&srctuple);
#else
hash = nf_conntrack_find_get(dev_net(skb->dev),
&nf_ct_zone_dflt,
&srctuple);
#endif
if (!hash)
return;
rev = true;
ct = nf_ct_tuplehash_to_ctrack(hash);
tuple = nf_ct_tuple(ct, !hash->tuple.dst.dir);
}
#if KERNEL_VERSION(4, 2, 0) > LINUX_VERSION_CODE
keys->src = rev ? tuple->dst.u3.ip : tuple->src.u3.ip;
keys->dst = rev ? tuple->src.u3.ip : tuple->dst.u3.ip;
#else
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;
#endif
#if KERNEL_VERSION(4, 2, 0) > LINUX_VERSION_CODE
if (keys->ports) {
keys->port16[0] = rev ? tuple->dst.u.all : tuple->src.u.all;
keys->port16[1] = rev ? tuple->src.u.all : tuple->dst.u.all;
}
#else
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
if (rev)
nf_ct_put(ct);
}
#else
static void cake_update_flowkeys(struct flow_keys *keys,
const struct sk_buff *skb)
{
/* There is nothing we can do here without CONNTRACK */
}
#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;
#if KERNEL_VERSION(4, 2, 0) > LINUX_VERSION_CODE
struct flow_keys keys;
#else
struct flow_keys keys, host_keys;
#endif
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;
#if KERNEL_VERSION(4, 2, 0) > LINUX_VERSION_CODE
skb_flow_dissect(skb, &keys);
if (flow_mode & CAKE_FLOW_NAT_FLAG)
cake_update_flowkeys(&keys, skb);
srchost_hash = jhash_1word((__force u32)keys.src, q->perturb);
dsthost_hash = jhash_1word((__force u32)keys.dst, q->perturb);
if (flow_mode & CAKE_FLOW_FLOWS)
flow_hash = jhash_3words((__force u32)keys.dst, (__force u32)keys.src ^ keys.ip_proto, (__force u32)keys.ports, q->perturb);
#else
/* Linux kernel 4.2.x have skb_flow_dissect_flow_keys which takes only 2
* arguments
*/
#if (KERNEL_VERSION(4, 2, 0) <= LINUX_VERSION_CODE) && (KERNEL_VERSION(4, 3, 0) > LINUX_VERSION_CODE)
skb_flow_dissect_flow_keys(skb, &keys);
#else
skb_flow_dissect_flow_keys(skb, &keys,
FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL);
#endif
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;
#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 8, 0)
host_keys.tags.vlan_id = 0;
#endif
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);
#endif
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++;
if (q->flows[outer_hash + k].set == CAKE_SET_BULK) {
q->hosts[q->flows[reduced_hash].srchost].srchost_bulk_flow_count--;
q->hosts[q->flows[reduced_hash].dsthost].dsthost_bulk_flow_count--;
}
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_bulk_flow_count)
break;
}
q->hosts[outer_hash + k].srchost_tag = srchost_hash;
found_src:
srchost_idx = outer_hash + k;
if (q->flows[reduced_hash].set == CAKE_SET_BULK)
q->hosts[srchost_idx].srchost_bulk_flow_count++;
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_bulk_flow_count)
break;
}
q->hosts[outer_hash + k].dsthost_tag = dsthost_hash;
found_dst:
dsthost_idx = outer_hash + k;
if (q->flows[reduced_hash].set == CAKE_SET_BULK)
q->hosts[dsthost_idx].dsthost_bulk_flow_count++;
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);