/* $OpenBSD: ieee80211_amrr.c,v 1.1 2006/06/17 19:07:19 damien Exp $ */ /*- * Copyright (c) 2006 * Damien Bergamini * * 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 __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 #include #include #include #include #include #include #ifdef INET #include #include #endif #include #include #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);