include/net/pie.h

   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  */
  28 struct 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  */
  51 struct 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  */
  71 struct 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  */
  84 struct pie_skb_cb {
  85         psched_time_t enqueue_time;
  86         u32 mem_usage;
  87 };
  88
  89 static 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
 101 static 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         vars->avg_dq_rate = 0;
 108 }
 109
 110 static 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
 116 static inline psched_time_t pie_get_enqueue_time(const struct sk_buff *skb)
 117 {
 118         return get_pie_cb(skb)->enqueue_time;
 119 }
 120
 121 static inline void pie_set_enqueue_time(struct sk_buff *skb)
 122 {
 123         get_pie_cb(skb)->enqueue_time = psched_get_time();
 124 }
 125
 126 bool pie_drop_early(struct Qdisc *sch, struct pie_params *params,
 127                     struct pie_vars *vars, u32 backlog, u32 packet_size);
 128
 129 void pie_process_dequeue(struct sk_buff *skb, struct pie_params *params,
 130                          struct pie_vars *vars, u32 backlog);
 131
 132 void pie_calculate_probability(struct pie_params *params, struct pie_vars *vars,
 133                                u32 backlog);
 134
 135 #endif