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/* $FreeBSD$ */
/* $NetBSD: ieee80211_rssadapt.c,v 1.9 2005/02/26 22:45:09 perry Exp $ */
/*-
* Copyright (c) 2003, 2004 David Young. All rights reserved.
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
* 3. The name of David Young may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY David Young ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL David
* Young BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
* OF SUCH DAMAGE.
*/
#include <sys/param.h>
#include <sys/sockio.h>
#include <sys/mbuf.h>
#include <sys/kernel.h>
#include <sys/socket.h>
#include <net/if.h>
#include <net/if_arp.h>
#include <net/ethernet.h>
#include <net/if_dl.h>
#include <net/if_media.h>
#include <net/if_types.h>
#include <net80211/ieee80211_var.h>
#include <dev/ral/if_ralrate.h>
#ifdef interpolate
#undef interpolate
#endif
#define interpolate(parm, old, new) ((parm##_old * (old) + \
(parm##_denom - parm##_old) * (new)) / \
parm##_denom)
static struct ral_rssadapt_expavgctl master_expavgctl = {
rc_decay_denom : 16,
rc_decay_old : 15,
rc_thresh_denom : 8,
rc_thresh_old : 4,
rc_avgrssi_denom : 8,
rc_avgrssi_old : 4
};
int
ral_rssadapt_choose(struct ral_rssadapt *ra, struct ieee80211_rateset *rs,
struct ieee80211_frame *wh, u_int len, const char *dvname, int do_not_adapt)
{
u_int16_t (*thrs)[IEEE80211_RATE_SIZE];
int flags = 0, i, rateidx = 0, thridx, top;
if ((wh->i_fc[0] & IEEE80211_FC0_TYPE_MASK) == IEEE80211_FC0_TYPE_CTL)
flags |= IEEE80211_RATE_BASIC;
for (i = 0, top = RAL_RSSADAPT_BKT0;
i < RAL_RSSADAPT_BKTS;
i++, top <<= RAL_RSSADAPT_BKTPOWER) {
thridx = i;
if (len <= top)
break;
}
thrs = &ra->ra_rate_thresh[thridx];
i = rs->rs_nrates;
while (--i >= 0) {
rateidx = i;
if ((rs->rs_rates[i] & flags) != flags)
continue;
if (do_not_adapt)
break;
if ((*thrs)[i] < ra->ra_avg_rssi)
break;
}
return rateidx;
}
void
ral_rssadapt_updatestats(struct ral_rssadapt *ra)
{
long interval;
ra->ra_pktrate =
(ra->ra_pktrate + 10 * (ra->ra_nfail + ra->ra_nok)) / 2;
ra->ra_nfail = ra->ra_nok = 0;
/* a node is eligible for its rate to be raised every 1/10 to 10
* seconds, more eligible in proportion to recent packet rates.
*/
interval = MAX(100000, 10000000 / MAX(1, 10 * ra->ra_pktrate));
ra->ra_raise_interval.tv_sec = interval / (1000 * 1000);
ra->ra_raise_interval.tv_usec = interval % (1000 * 1000);
}
void
ral_rssadapt_input(struct ieee80211com *ic, struct ieee80211_node *ni,
struct ral_rssadapt *ra, int rssi)
{
ra->ra_avg_rssi = interpolate(master_expavgctl.rc_avgrssi,
ra->ra_avg_rssi, (rssi << 8));
}
/*
* Adapt the data rate to suit the conditions. When a transmitted
* packet is dropped after RAL_RSSADAPT_RETRY_LIMIT retransmissions,
* raise the RSS threshold for transmitting packets of similar length at
* the same data rate.
*/
void
ral_rssadapt_lower_rate(struct ieee80211com *ic, struct ieee80211_node *ni,
struct ral_rssadapt *ra, struct ral_rssdesc *id)
{
struct ieee80211_rateset *rs = &ni->ni_rates;
u_int16_t last_thr;
u_int i, thridx, top;
ra->ra_nfail++;
if (id->id_rateidx >= rs->rs_nrates)
return;
for (i = 0, top = RAL_RSSADAPT_BKT0;
i < RAL_RSSADAPT_BKTS;
i++, top <<= RAL_RSSADAPT_BKTPOWER) {
thridx = i;
if (id->id_len <= top)
break;
}
last_thr = ra->ra_rate_thresh[thridx][id->id_rateidx];
ra->ra_rate_thresh[thridx][id->id_rateidx] =
interpolate(master_expavgctl.rc_thresh, last_thr,
(id->id_rssi << 8));
}
void
ral_rssadapt_raise_rate(struct ieee80211com *ic, struct ral_rssadapt *ra,
struct ral_rssdesc *id)
{
u_int16_t (*thrs)[IEEE80211_RATE_SIZE], newthr, oldthr;
struct ieee80211_node *ni = id->id_node;
struct ieee80211_rateset *rs = &ni->ni_rates;
int i, rate, top;
ra->ra_nok++;
if (!ratecheck(&ra->ra_last_raise, &ra->ra_raise_interval))
return;
for (i = 0, top = RAL_RSSADAPT_BKT0;
i < RAL_RSSADAPT_BKTS;
i++, top <<= RAL_RSSADAPT_BKTPOWER) {
thrs = &ra->ra_rate_thresh[i];
if (id->id_len <= top)
break;
}
if (id->id_rateidx + 1 < rs->rs_nrates &&
(*thrs)[id->id_rateidx + 1] > (*thrs)[id->id_rateidx]) {
rate = (rs->rs_rates[id->id_rateidx + 1] & IEEE80211_RATE_VAL);
oldthr = (*thrs)[id->id_rateidx + 1];
if ((*thrs)[id->id_rateidx] == 0)
newthr = ra->ra_avg_rssi;
else
newthr = (*thrs)[id->id_rateidx];
(*thrs)[id->id_rateidx + 1] =
interpolate(master_expavgctl.rc_decay, oldthr, newthr);
}
}
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