1/*	$OpenBSD: ieee80211_ra.h,v 1.2 2021/10/11 09:01:06 stsp Exp $	*/
2
3/*
4 * Copyright (c) 2021 Christian Ehrhardt <ehrhardt@genua.de>
5 * Copyright (c) 2021 Stefan Sperling <stsp@openbsd.org>
6 *
7 * Permission to use, copy, modify, and distribute this software for any
8 * purpose with or without fee is hereby granted, provided that the above
9 * copyright notice and this permission notice appear in all copies.
10 *
11 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
17 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18 */
19
20/*
21 * Goodput statistics struct. Measures the effective data rate of an MCS.
22 * All uint64_t numbers in this struct use fixed-point arithmetic.
23 */
24struct ieee80211_ra_goodput_stats {
25	uint64_t measured;	/* Most recently measured goodput. */
26	uint64_t average;	/* Average measured goodput. */
27	uint64_t stddeviation;	/* Goodput standard deviation. */
28 	uint64_t loss;		/* This rate's loss percentage SFER. */
29	uint32_t nprobe_pkts;	/* Number of packets in current probe. */
30	uint32_t nprobe_fail;	/* Number of failed packets. */
31};
32
33/*
34 * Rate adaptation state.
35 *
36 * Drivers should not modify any fields of this structure directly.
37 * Use ieee80211_ra_init() and ieee80211_ra_add_stats() only.
38 */
39struct ieee80211_ra_node {
40	/* Bitmaps MCS 0-31. */
41	uint32_t valid_probes;
42	uint32_t valid_rates;
43	uint32_t candidate_rates;
44	uint32_t probed_rates;
45
46	/* Probing state. */
47	int probing;
48#define IEEE80211_RA_NOT_PROBING	0x0
49#define IEEE80211_RA_PROBING_DOWN	0x1
50#define IEEE80211_RA_PROBING_UP		0x2
51#define IEEE80211_RA_PROBING_INTER	0x4 /* combined with UP or DOWN */
52
53	/* The current best MCS found by probing. */
54	int best_mcs;
55
56	/* Goodput statistics for each MCS. */
57	struct ieee80211_ra_goodput_stats g[IEEE80211_HT_RATESET_NUM_MCS];
58};
59
60/* Initialize rate adaptation state. */
61void	ieee80211_ra_node_init(struct ieee80211_ra_node *);
62
63/*
64 * Drivers report information about 802.11n/HT Tx attempts here.
65 * mcs: The HT MCS used during this Tx attempt.
66 * total: How many Tx attempts (initial attempt + any retries) were made?
67 * fail: How many of these Tx attempts failed?
68 */
69void	ieee80211_ra_add_stats_ht(struct ieee80211_ra_node *,
70	    struct ieee80211com *, struct ieee80211_node *,
71	    int mcs, unsigned int total, unsigned int fail);
72
73/* Drivers call this function to update ni->ni_txmcs. */
74void	ieee80211_ra_choose(struct ieee80211_ra_node *,
75	    struct ieee80211com *, struct ieee80211_node *);
76
77/* Get the HT rateset for a particular HT MCS with 40MHz and/or SGI on/off. */
78const struct ieee80211_ht_rateset * ieee80211_ra_get_ht_rateset(int mcs,
79	    int chan40, int sgi);
80
81/* Check whether SGI should be used. */
82int ieee80211_ra_use_ht_sgi(struct ieee80211_node *);
83