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/* $OpenBSD: ieee80211_amrr.c,v 1.1 2006/06/17 19:07:19 damien Exp $ */
/*-
* Copyright (c) 2006
* Damien Bergamini <damien.bergamini@free.fr>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*-
* Naive implementation of the Adaptive Multi Rate Retry algorithm:
*
* "IEEE 802.11 Rate Adaptation: A Practical Approach"
* Mathieu Lacage, Hossein Manshaei, Thierry Turletti
* INRIA Sophia - Projet Planete
* http://www-sop.inria.fr/rapports/sophia/RR-5208.html
*/
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/if_media.h>
#ifdef INET
#include <netinet/in.h>
#include <netinet/if_ether.h>
#endif
#include <net80211/ieee80211_var.h>
#include <net80211/ieee80211_amrr.h>
#define is_success(amn) \
((amn)->amn_retrycnt < (amn)->amn_txcnt / 10)
#define is_failure(amn) \
((amn)->amn_retrycnt > (amn)->amn_txcnt / 3)
#define is_enough(amn) \
((amn)->amn_txcnt > 10)
#define is_min_rate(ni) \
((ni)->ni_txrate == 0)
#define is_max_rate(ni) \
((ni)->ni_txrate == (ni)->ni_rates.rs_nrates - 1)
#define increase_rate(ni) \
((ni)->ni_txrate++)
#define decrease_rate(ni) \
((ni)->ni_txrate--)
#define reset_cnt(amn) \
do { (amn)->amn_txcnt = (amn)->amn_retrycnt = 0; } while (0)
void
ieee80211_amrr_init(struct ieee80211_amrr *amrr,
struct ieee80211com *ic, int amin, int amax)
{
/* XXX bounds check? */
amrr->amrr_min_success_threshold = amin;
amrr->amrr_max_success_threshold = amax;
amrr->amrr_ic = ic;
}
void
ieee80211_amrr_node_init(struct ieee80211_amrr *amrr,
struct ieee80211_amrr_node *amn)
{
amn->amn_success = 0;
amn->amn_recovery = 0;
amn->amn_txcnt = amn->amn_retrycnt = 0;
amn->amn_success_threshold = amrr->amrr_min_success_threshold;
}
/*
* Update ni->ni_txrate.
*/
void
ieee80211_amrr_choose(struct ieee80211_amrr *amrr, struct ieee80211_node *ni,
struct ieee80211_amrr_node *amn)
{
int need_change = 0;
if (is_success(amn) && is_enough(amn)) {
amn->amn_success++;
if (amn->amn_success >= amn->amn_success_threshold &&
!is_max_rate(ni)) {
amn->amn_recovery = 1;
amn->amn_success = 0;
increase_rate(ni);
IEEE80211_DPRINTF(amrr->amrr_ic, IEEE80211_MSG_RATECTL,
"AMRR increasing rate %d (txcnt=%d "
"retrycnt=%d)\n",
ni->ni_rates.rs_rates[ni->ni_txrate] &
IEEE80211_RATE_VAL,
amn->amn_txcnt, amn->amn_retrycnt);
need_change = 1;
} else {
amn->amn_recovery = 0;
}
} else if (is_failure(amn)) {
amn->amn_success = 0;
if (!is_min_rate(ni)) {
if (amn->amn_recovery) {
amn->amn_success_threshold *= 2;
if (amn->amn_success_threshold >
amrr->amrr_max_success_threshold)
amn->amn_success_threshold =
amrr->amrr_max_success_threshold;
} else {
amn->amn_success_threshold =
amrr->amrr_min_success_threshold;
}
decrease_rate(ni);
IEEE80211_DPRINTF(amrr->amrr_ic, IEEE80211_MSG_RATECTL,
"AMRR decreasing rate %d (txcnt=%d "
"retrycnt=%d)\n",
ni->ni_rates.rs_rates[ni->ni_txrate] &
IEEE80211_RATE_VAL,
amn->amn_txcnt, amn->amn_retrycnt);
need_change = 1;
}
amn->amn_recovery = 0;
}
if (is_enough(amn) || need_change)
reset_cnt(amn);
}
/*
* Module glue.
*/
static int
amrr_modevent(module_t mod, int type, void *unused)
{
switch (type) {
case MOD_LOAD:
if (bootverbose)
printf("wlan_amrr: <AMRR Transmit Rate Control Algorithm>\n");
return 0;
case MOD_UNLOAD:
return 0;
}
return EINVAL;
}
static moduledata_t amrr_mod = {
"wlan_amrr",
amrr_modevent,
0
};
DECLARE_MODULE(wlan_amrr, amrr_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST);
MODULE_VERSION(wlan_amrr, 1);
MODULE_DEPEND(wlan_amrr, wlan, 1, 1, 1);
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