ieee80211_amrr.c revision 169281 
1/*	$OpenBSD: ieee80211_amrr.c,v 1.1 2006/06/17 19:07:19 damien Exp $	*/
2
3/*-
4 * Copyright (c) 2006
5 *	Damien Bergamini <damien.bergamini@free.fr>
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#include <sys/cdefs.h>
21__FBSDID("$FreeBSD: head/sys/net80211/ieee80211_amrr.c 169281 2007-05-05 11:07:52Z sephe $");
22
23/*-
24 * Naive implementation of the Adaptive Multi Rate Retry algorithm:
25 *
26 * "IEEE 802.11 Rate Adaptation: A Practical Approach"
27 *  Mathieu Lacage, Hossein Manshaei, Thierry Turletti
28 *  INRIA Sophia - Projet Planete
29 *  http://www-sop.inria.fr/rapports/sophia/RR-5208.html
30 */
31#include <sys/param.h>
32#include <sys/kernel.h>
33#include <sys/module.h>
34#include <sys/socket.h>
35#include <sys/sysctl.h>
36
37#include <net/if.h>
38#include <net/if_media.h>
39
40#ifdef INET
41#include <netinet/in.h>
42#include <netinet/if_ether.h>
43#endif
44
45#include <net80211/ieee80211_var.h>
46#include <net80211/ieee80211_amrr.h>
47
48#define is_success(amn)	\
49	((amn)->amn_retrycnt < (amn)->amn_txcnt / 10)
50#define is_failure(amn)	\
51	((amn)->amn_retrycnt > (amn)->amn_txcnt / 3)
52#define is_enough(amn)		\
53	((amn)->amn_txcnt > 10)
54#define is_min_rate(ni)		\
55	((ni)->ni_txrate == 0)
56#define is_max_rate(ni)		\
57	((ni)->ni_txrate == (ni)->ni_rates.rs_nrates - 1)
58#define increase_rate(ni)	\
59	((ni)->ni_txrate++)
60#define decrease_rate(ni)	\
61	((ni)->ni_txrate--)
62#define reset_cnt(amn)		\
63	do { (amn)->amn_txcnt = (amn)->amn_retrycnt = 0; } while (0)
64
65void
66ieee80211_amrr_init(struct ieee80211_amrr *amrr,
67    struct ieee80211com *ic, int min, int max)
68{
69	/* XXX bounds check? */
70	amrr->amrr_min_success_threshold = min;
71	amrr->amrr_max_success_threshold = max;
72	amrr->amrr_ic = ic;
73}
74
75void
76ieee80211_amrr_node_init(struct ieee80211_amrr *amrr,
77    struct ieee80211_amrr_node *amn)
78{
79	amn->amn_success = 0;
80	amn->amn_recovery = 0;
81	amn->amn_txcnt = amn->amn_retrycnt = 0;
82	amn->amn_success_threshold = amrr->amrr_min_success_threshold;
83}
84
85/*
86 * Update ni->ni_txrate.
87 */
88void
89ieee80211_amrr_choose(struct ieee80211_amrr *amrr, struct ieee80211_node *ni,
90    struct ieee80211_amrr_node *amn)
91{
92	int need_change = 0;
93
94	if (is_success(amn) && is_enough(amn)) {
95		amn->amn_success++;
96		if (amn->amn_success >= amn->amn_success_threshold &&
97		    !is_max_rate(ni)) {
98			amn->amn_recovery = 1;
99			amn->amn_success = 0;
100			increase_rate(ni);
101			IEEE80211_DPRINTF(amrr->amrr_ic, IEEE80211_MSG_RATECTL,
102			    "AMRR increasing rate %d (txcnt=%d "
103			    "retrycnt=%d)\n",
104			    ni->ni_rates.rs_rates[ni->ni_txrate] &
105				IEEE80211_RATE_VAL,
106			    amn->amn_txcnt, amn->amn_retrycnt);
107			need_change = 1;
108		} else {
109			amn->amn_recovery = 0;
110		}
111	} else if (is_failure(amn)) {
112		amn->amn_success = 0;
113		if (!is_min_rate(ni)) {
114			if (amn->amn_recovery) {
115				amn->amn_success_threshold *= 2;
116				if (amn->amn_success_threshold >
117				    amrr->amrr_max_success_threshold)
118					amn->amn_success_threshold =
119					    amrr->amrr_max_success_threshold;
120			} else {
121				amn->amn_success_threshold =
122				    amrr->amrr_min_success_threshold;
123			}
124			decrease_rate(ni);
125			IEEE80211_DPRINTF(amrr->amrr_ic, IEEE80211_MSG_RATECTL,
126			    "AMRR decreasing rate %d (txcnt=%d "
127			    "retrycnt=%d)\n",
128			    ni->ni_rates.rs_rates[ni->ni_txrate] &
129				IEEE80211_RATE_VAL,
130			    amn->amn_txcnt, amn->amn_retrycnt);
131			need_change = 1;
132		}
133		amn->amn_recovery = 0;
134	}
135
136	if (is_enough(amn) || need_change)
137		reset_cnt(amn);
138}
139
140/*
141 * Module glue.
142 */
143static int
144amrr_modevent(module_t mod, int type, void *unused)
145{
146	switch (type) {
147	case MOD_LOAD:
148		if (bootverbose)
149			printf("wlan_amrr: <AMRR Transmit Rate Control Algorithm>\n");
150		return 0;
151	case MOD_UNLOAD:
152		return 0;
153	}
154	return EINVAL;
155}
156
157static moduledata_t amrr_mod = {
158	"wlan_amrr",
159	amrr_modevent,
160	0
161};
162DECLARE_MODULE(wlan_amrr, amrr_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST);
163MODULE_VERSION(wlan_amrr, 1);
164MODULE_DEPEND(wlan_amrr, wlan, 1, 1, 1);
165