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1/* SPDX-License-Identifier: GPL-2.0-only */
2#ifndef __NET_SCHED_PIE_H
3#define __NET_SCHED_PIE_H
4
5#include <linux/ktime.h>
6#include <linux/skbuff.h>
7#include <linux/types.h>
8#include <net/inet_ecn.h>
9#include <net/pkt_sched.h>
10
11#define MAX_PROB (U64_MAX >> BITS_PER_BYTE)
12#define DTIME_INVALID U64_MAX
13#define QUEUE_THRESHOLD 16384
14#define DQCOUNT_INVALID -1
15#define PIE_SCALE 8
16
17/**
18 * struct pie_params - contains pie parameters
19 * @target: target delay in pschedtime
20 * @tupdate: interval at which drop probability is calculated
21 * @limit: total number of packets that can be in the queue
22 * @alpha: parameter to control drop probability
23 * @beta: parameter to control drop probability
24 * @ecn: is ECN marking of packets enabled
25 * @bytemode: is drop probability scaled based on pkt size
26 * @dq_rate_estimator: is Little's law used for qdelay calculation
27 */
28struct pie_params {
29 psched_time_t target;
30 u32 tupdate;
31 u32 limit;
32 u32 alpha;
33 u32 beta;
34 u8 ecn;
35 u8 bytemode;
36 u8 dq_rate_estimator;
37};
38
39/**
40 * struct pie_vars - contains pie variables
41 * @qdelay: current queue delay
42 * @qdelay_old: queue delay in previous qdelay calculation
43 * @burst_time: burst time allowance
44 * @dq_tstamp: timestamp at which dq rate was last calculated
45 * @prob: drop probability
46 * @accu_prob: accumulated drop probability
47 * @dq_count: number of bytes dequeued in a measurement cycle
48 * @avg_dq_rate: calculated average dq rate
49 * @backlog_old: queue backlog during previous qdelay calculation
50 */
51struct pie_vars {
52 psched_time_t qdelay;
53 psched_time_t qdelay_old;
54 psched_time_t burst_time;
55 psched_time_t dq_tstamp;
56 u64 prob;
57 u64 accu_prob;
58 u64 dq_count;
59 u32 avg_dq_rate;
60 u32 backlog_old;
61};
62
63/**
64 * struct pie_stats - contains pie stats
65 * @packets_in: total number of packets enqueued
66 * @dropped: packets dropped due to pie action
67 * @overlimit: packets dropped due to lack of space in queue
68 * @ecn_mark: packets marked with ECN
69 * @maxq: maximum queue size
70 */
71struct pie_stats {
72 u32 packets_in;
73 u32 dropped;
74 u32 overlimit;
75 u32 ecn_mark;
76 u32 maxq;
77};
78
79/**
80 * struct pie_skb_cb - contains private skb vars
81 * @enqueue_time: timestamp when the packet is enqueued
82 * @mem_usage: size of the skb during enqueue
83 */
84struct pie_skb_cb {
85 psched_time_t enqueue_time;
86 u32 mem_usage;
87};
88
89static inline void pie_params_init(struct pie_params *params)
90{
91 params->target = PSCHED_NS2TICKS(15 * NSEC_PER_MSEC); /* 15 ms */
92 params->tupdate = usecs_to_jiffies(15 * USEC_PER_MSEC); /* 15 ms */
93 params->limit = 1000;
94 params->alpha = 2;
95 params->beta = 20;
96 params->ecn = false;
97 params->bytemode = false;
98 params->dq_rate_estimator = false;
99}
100
101static inline void pie_vars_init(struct pie_vars *vars)
102{
103 vars->burst_time = PSCHED_NS2TICKS(150 * NSEC_PER_MSEC); /* 150 ms */
104 vars->dq_tstamp = DTIME_INVALID;
105 vars->accu_prob = 0;
106 vars->dq_count = DQCOUNT_INVALID;
107 WRITE_ONCE(vars->avg_dq_rate, 0);
108}
109
110static inline struct pie_skb_cb *get_pie_cb(const struct sk_buff *skb)
111{
112 qdisc_cb_private_validate(skb, sizeof(struct pie_skb_cb));
113 return (struct pie_skb_cb *)qdisc_skb_cb(skb)->data;
114}
115
116static inline psched_time_t pie_get_enqueue_time(const struct sk_buff *skb)
117{
118 return get_pie_cb(skb)->enqueue_time;
119}
120
121static inline void pie_set_enqueue_time(struct sk_buff *skb)
122{
123 get_pie_cb(skb)->enqueue_time = psched_get_time();
124}
125
126bool pie_drop_early(struct Qdisc *sch, struct pie_params *params,
127 struct pie_vars *vars, u32 backlog, u32 packet_size);
128
129void pie_process_dequeue(struct sk_buff *skb, struct pie_params *params,
130 struct pie_vars *vars, u32 backlog);
131
132void pie_calculate_probability(struct pie_params *params, struct pie_vars *vars,
133 u32 backlog);
134
135#endif