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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 "opt_wlan.h"
#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)
static void amrr_sysctlattach(struct ieee80211_amrr *amrr,
struct sysctl_ctx_list *ctx, struct sysctl_oid *tree);
/* number of references from net80211 layer */
static int nrefs = 0;
void
ieee80211_amrr_setinterval(struct ieee80211_amrr *amrr, int msecs)
{
int t;
if (msecs < 100)
msecs = 100;
t = msecs_to_ticks(msecs);
amrr->amrr_interval = (t < 1) ? 1 : t;
}
void
ieee80211_amrr_init(struct ieee80211_amrr *amrr,
struct ieee80211vap *vap, int amin, int amax, int interval)
{
/* XXX bounds check? */
amrr->amrr_min_success_threshold = amin;
amrr->amrr_max_success_threshold = amax;
ieee80211_amrr_setinterval(amrr, interval);
amrr_sysctlattach(amrr, vap->iv_sysctl, vap->iv_oid);
}
void
ieee80211_amrr_cleanup(struct ieee80211_amrr *amrr)
{
}
void
ieee80211_amrr_node_init(struct ieee80211_amrr *amrr,
struct ieee80211_amrr_node *amn, struct ieee80211_node *ni)
{
const struct ieee80211_rateset *rs = &ni->ni_rates;
amn->amn_amrr = amrr;
amn->amn_success = 0;
amn->amn_recovery = 0;
amn->amn_txcnt = amn->amn_retrycnt = 0;
amn->amn_success_threshold = amrr->amrr_min_success_threshold;
/* pick initial rate */
for (amn->amn_rix = rs->rs_nrates - 1;
amn->amn_rix > 0 && (rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL) > 72;
amn->amn_rix--)
;
ni->ni_txrate = rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL;
amn->amn_ticks = ticks;
IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
"AMRR initial rate %d", ni->ni_txrate);
}
static int
amrr_update(struct ieee80211_amrr *amrr, struct ieee80211_amrr_node *amn,
struct ieee80211_node *ni)
{
int rix = amn->amn_rix;
KASSERT(is_enough(amn), ("txcnt %d", amn->amn_txcnt));
if (is_success(amn)) {
amn->amn_success++;
if (amn->amn_success >= amn->amn_success_threshold &&
rix + 1 < ni->ni_rates.rs_nrates) {
amn->amn_recovery = 1;
amn->amn_success = 0;
rix++;
IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
"AMRR increasing rate %d (txcnt=%d retrycnt=%d)",
ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL,
amn->amn_txcnt, amn->amn_retrycnt);
} else {
amn->amn_recovery = 0;
}
} else if (is_failure(amn)) {
amn->amn_success = 0;
if (rix > 0) {
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;
}
rix--;
IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
"AMRR decreasing rate %d (txcnt=%d retrycnt=%d)",
ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL,
amn->amn_txcnt, amn->amn_retrycnt);
}
amn->amn_recovery = 0;
}
/* reset counters */
amn->amn_txcnt = 0;
amn->amn_retrycnt = 0;
return rix;
}
/*
* Return the rate index to use in sending a data frame.
* Update our internal state if it's been long enough.
* If the rate changes we also update ni_txrate to match.
*/
int
ieee80211_amrr_choose(struct ieee80211_node *ni,
struct ieee80211_amrr_node *amn)
{
struct ieee80211_amrr *amrr = amn->amn_amrr;
int rix;
if (is_enough(amn) && (ticks - amn->amn_ticks) > amrr->amrr_interval) {
rix = amrr_update(amrr, amn, ni);
if (rix != amn->amn_rix) {
/* update public rate */
ni->ni_txrate =
ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL;
amn->amn_rix = rix;
}
amn->amn_ticks = ticks;
} else
rix = amn->amn_rix;
return rix;
}
static int
amrr_sysctl_interval(SYSCTL_HANDLER_ARGS)
{
struct ieee80211_amrr *amrr = arg1;
int msecs = ticks_to_msecs(amrr->amrr_interval);
int error;
error = sysctl_handle_int(oidp, &msecs, 0, req);
if (error || !req->newptr)
return error;
ieee80211_amrr_setinterval(amrr, msecs);
return 0;
}
static void
amrr_sysctlattach(struct ieee80211_amrr *amrr,
struct sysctl_ctx_list *ctx, struct sysctl_oid *tree)
{
SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
"amrr_rate_interval", CTLTYPE_INT | CTLFLAG_RW, amrr,
0, amrr_sysctl_interval, "I", "amrr operation interval (ms)");
/* XXX bounds check values */
SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
"amrr_max_sucess_threshold", CTLFLAG_RW,
&amrr->amrr_max_success_threshold, 0, "");
SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
"amrr_min_sucess_threshold", CTLFLAG_RW,
&amrr->amrr_min_success_threshold, 0, "");
}
/*
* Module glue.
*/
IEEE80211_RATE_MODULE(amrr, 1);
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