Move AMRR rate control algorithm out of wpi(4) and ural(4), into net80211.

ok brad@

8 files changed, 276 insertions, 270 deletions

diff --git a/sys/conf/files b/sys/conf/files
index 078e613cb8c..2012f96135d 100644
--- a/sys/conf/files
+++ b/sys/conf/files
@@ -1,4 +1,4 @@
-#	$OpenBSD: files,v 1.376 2006/06/02 20:25:09 pedro Exp $
+#	$OpenBSD: files,v 1.377 2006/06/17 19:07:19 damien Exp $
 #	$NetBSD: files,v 1.87 1996/05/19 17:17:50 jonathan Exp $
 
 #	@(#)files.newconf	7.5 (Berkeley) 5/10/93
@@ -742,6 +742,7 @@ file net/if_enc.c			enc			needs-count
 file net/if_gre.c			gre			needs-count
 file net/if_trunk.c			trunk			needs-count
 file net80211/ieee80211.c		wlan
+file net80211/ieee80211_amrr.c		wlan
 file net80211/ieee80211_crypto.c	wlan
 file net80211/ieee80211_input.c		wlan
 file net80211/ieee80211_ioctl.c		wlan
diff --git a/sys/dev/pci/if_wpi.c b/sys/dev/pci/if_wpi.c
index 998ecf8553d..7772e78f522 100644
--- a/sys/dev/pci/if_wpi.c
+++ b/sys/dev/pci/if_wpi.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_wpi.c,v 1.20 2006/06/17 18:35:46 damien Exp $	*/
+/*	$OpenBSD: if_wpi.c,v 1.21 2006/06/17 19:07:19 damien Exp $	*/
 
 /*-
  * Copyright (c) 2006
@@ -58,6 +58,7 @@
 #include <netinet/ip.h>
 
 #include <net80211/ieee80211_var.h>
+#include <net80211/ieee80211_amrr.h>
 #include <net80211/ieee80211_radiotap.h>
 
 #include <dev/pci/if_wpireg.h>
@@ -103,8 +104,6 @@ int		wpi_alloc_tx_ring(struct wpi_softc *, struct wpi_tx_ring *,
 void		wpi_reset_tx_ring(struct wpi_softc *, struct wpi_tx_ring *);
 void		wpi_free_tx_ring(struct wpi_softc *, struct wpi_tx_ring *);
 struct		ieee80211_node *wpi_node_alloc(struct ieee80211com *);
-void		wpi_node_copy(struct ieee80211com *, struct ieee80211_node *,
-		    const struct ieee80211_node *);
 int		wpi_media_change(struct ifnet *);
 int		wpi_newstate(struct ieee80211com *, enum ieee80211_state, int);
 void		wpi_mem_lock(struct wpi_softc *);
@@ -121,8 +120,7 @@ int		wpi_load_firmware(struct wpi_softc *, uint32_t, const char *,
 		    int);
 void		wpi_rx_intr(struct wpi_softc *, struct wpi_rx_desc *,
 		    struct wpi_rx_data *);
-void		wpi_tx_intr(struct wpi_softc *, struct wpi_rx_desc *,
-		    struct wpi_rx_data *);
+void		wpi_tx_intr(struct wpi_softc *, struct wpi_rx_desc *);
 void		wpi_cmd_intr(struct wpi_softc *, struct wpi_rx_desc *);
 void		wpi_notif_intr(struct wpi_softc *);
 int		wpi_intr(void *);
@@ -147,11 +145,10 @@ int		wpi_reset(struct wpi_softc *);
 void		wpi_hw_config(struct wpi_softc *);
 int		wpi_init(struct ifnet *);
 void		wpi_stop(struct ifnet *, int);
-
-/* rate control algorithm: should be moved to net80211 */
-void		wpi_amrr_init(struct wpi_amrr *);
+void		wpi_iter_func(void *, struct ieee80211_node *);
 void		wpi_amrr_timeout(void *);
-void		wpi_amrr_ratectl(void *, struct ieee80211_node *);
+void		wpi_newassoc(struct ieee80211com *, struct ieee80211_node *,
+		    int);
 
 #define WPI_DEBUG
 
@@ -332,13 +329,15 @@ wpi_attach(struct device *parent, struct device *self, void *aux)
 	if_attach(ifp);
 	ieee80211_ifattach(ifp);
 	ic->ic_node_alloc = wpi_node_alloc;
-	ic->ic_node_copy = wpi_node_copy;
+	ic->ic_newassoc = wpi_newassoc;
 
 	/* override state transition machine */
 	sc->sc_newstate = ic->ic_newstate;
 	ic->ic_newstate = wpi_newstate;
 	ieee80211_media_init(ifp, wpi_media_change, ieee80211_media_status);
 
+	sc->amrr.amrr_min_success_threshold =  1;
+	sc->amrr.amrr_max_success_threshold = 15;
 	timeout_set(&sc->amrr_ch, wpi_amrr_timeout, sc);
 
 	sc->powerhook = powerhook_establish(wpi_power, sc);
@@ -737,26 +736,15 @@ wpi_free_tx_ring(struct wpi_softc *sc, struct wpi_tx_ring *ring)
 	}
 }
 
-/* ARGSUSED */
 struct ieee80211_node *
 wpi_node_alloc(struct ieee80211com *ic)
 {
-	struct wpi_amrr *amrr;
+	struct wpi_node *wn;
 
-	amrr = malloc(sizeof (struct wpi_amrr), M_DEVBUF, M_NOWAIT);
-	if (amrr != NULL) {
-		bzero(amrr, sizeof (struct wpi_amrr));
-		wpi_amrr_init(amrr);
-	}
-	return (struct ieee80211_node *)amrr;
-}
-
-void
-wpi_node_copy(struct ieee80211com *ic, struct ieee80211_node *dst,
-    const struct ieee80211_node *src)
-{
-	*dst = *src;
-	wpi_amrr_init((struct wpi_amrr *)dst);
+	wn = malloc(sizeof (struct wpi_node), M_DEVBUF, M_NOWAIT);
+	if (wn != NULL)
+		bzero(wn, sizeof (struct wpi_node));
+	return (struct ieee80211_node *)wn;
 }
 
 int
@@ -838,6 +826,11 @@ wpi_newstate(struct ieee80211com *ic, enum ieee80211_state nstate, int arg)
 			return error;
 		}
 
+		if (ic->ic_opmode == IEEE80211_M_STA) {
+			/* fake a join to init the tx rate */
+			wpi_newassoc(ic, ic->ic_bss, 1);
+		}
+
 		/* start automatic rate control timer */
 		if (ic->ic_fixed_rate == -1)
 			timeout_add(&sc->amrr_ch, hz / 2);
@@ -1207,15 +1200,14 @@ wpi_rx_intr(struct wpi_softc *sc, struct wpi_rx_desc *desc,
 }
 
 void
-wpi_tx_intr(struct wpi_softc *sc, struct wpi_rx_desc *desc,
-    struct wpi_rx_data *data)
+wpi_tx_intr(struct wpi_softc *sc, struct wpi_rx_desc *desc)
 {
 	struct ieee80211com *ic = &sc->sc_ic;
 	struct ifnet *ifp = &ic->ic_if;
 	struct wpi_tx_ring *ring = &sc->txq[desc->qid & 0x3];
-	struct wpi_tx_data *txdata = &ring->data[desc->idx];
+	struct wpi_tx_data *data = &ring->data[desc->idx];
 	struct wpi_tx_stat *stat = (struct wpi_tx_stat *)(desc + 1);
-	struct wpi_amrr *amrr = (struct wpi_amrr *)txdata->ni;
+	struct wpi_node *wn = (struct wpi_node *)data->ni;
 
 	DPRINTFN(4, ("tx done: qid=%d idx=%d retries=%d nkill=%d rate=%x "
 	    "duration=%d status=%x\n", desc->qid, desc->idx, stat->ntries,
@@ -1227,18 +1219,18 @@ wpi_tx_intr(struct wpi_softc *sc, struct wpi_rx_desc *desc,
 	 * XXX we should not count mgmt frames since they're always sent at
 	 * the lowest available bit-rate.
 	 */
-	amrr->txcnt++;
+	wn->amn.amn_txcnt++;
 	if (stat->ntries > 0) {
 		DPRINTFN(3, ("tx intr ntries %d\n", stat->ntries));
-		amrr->retrycnt++;
+		wn->amn.amn_retrycnt++;
 	}
 
-	bus_dmamap_unload(sc->sc_dmat, txdata->map);
+	bus_dmamap_unload(sc->sc_dmat, data->map);
 
-	m_freem(txdata->m);
-	txdata->m = NULL;
-	ieee80211_release_node(ic, txdata->ni);
-	txdata->ni = NULL;
+	m_freem(data->m);
+	data->m = NULL;
+	ieee80211_release_node(ic, data->ni);
+	data->ni = NULL;
 
 	if ((letoh32(stat->status) & 0xff) != 1)
 		ifp->if_oerrors++;
@@ -1302,7 +1294,7 @@ wpi_notif_intr(struct wpi_softc *sc)
 
 		case WPI_TX_DONE:
 			/* a 802.11 frame has been transmitted */
-			wpi_tx_intr(sc, desc, data);
+			wpi_tx_intr(sc, desc);
 			break;
 
 		case WPI_UC_READY:
@@ -1990,7 +1982,7 @@ wpi_auth(struct wpi_softc *sc)
 {
 	struct ieee80211com *ic = &sc->sc_ic;
 	struct ieee80211_node *ni = ic->ic_bss;
-	struct wpi_node node;
+	struct wpi_node_info node;
 	int error;
 
 	/* update adapter's configuration */
@@ -2173,7 +2165,7 @@ wpi_config(struct wpi_softc *sc)
 	struct wpi_txpower txpower;
 	struct wpi_power power;
 	struct wpi_bluetooth bluetooth;
-	struct wpi_node node;
+	struct wpi_node_info node;
 	int error;
 
 	/* Intel's binary only daemon is a joke.. */
@@ -2585,52 +2577,13 @@ wpi_stop(struct ifnet *ifp, int disable)
 	WPI_WRITE(sc, WPI_RESET, tmp | WPI_SW_RESET);
 }
 
-/*-
- * 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
- */
-#define is_success(amrr)	\
-	((amrr)->retrycnt < (amrr)->txcnt / 10)
-#define is_failure(amrr)	\
-	((amrr)->retrycnt > (amrr)->txcnt / 3)
-#define is_enough(amrr)		\
-	((amrr)->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(amrr)		\
-	do { (amrr)->txcnt = (amrr)->retrycnt = 0; } while (0)
-
-#define WPI_AMRR_MIN_SUCCESS_THRESHOLD	 1
-#define WPI_AMRR_MAX_SUCCESS_THRESHOLD	15
-
-/* XXX should reset all nodes on S_INIT */
 void
-wpi_amrr_init(struct wpi_amrr *amrr)
+wpi_iter_func(void *arg, struct ieee80211_node *ni)
 {
-	struct ieee80211_node *ni = &amrr->ni;
-	int i;
-
-	amrr->success = 0;
-	amrr->recovery = 0;
-	amrr->txcnt = amrr->retrycnt = 0;
-	amrr->success_threshold = WPI_AMRR_MIN_SUCCESS_THRESHOLD;
-
-	/* set rate to some reasonable initial value */
-	ni = &amrr->ni;
-	for (i = ni->ni_rates.rs_nrates - 1;
-	     i > 0 && (ni->ni_rates.rs_rates[i] & IEEE80211_RATE_VAL) > 72;
-	     i--);
+	struct wpi_softc *sc = arg;
+	struct wpi_node *wn = (struct wpi_node *)ni;
 
-	ni->ni_txrate = i;
+	ieee80211_amrr_choose(&sc->amrr, ni, &wn->amn);
 }
 
 void
@@ -2640,58 +2593,26 @@ wpi_amrr_timeout(void *arg)
 	struct ieee80211com *ic = &sc->sc_ic;
 
 	if (ic->ic_opmode == IEEE80211_M_STA)
-		wpi_amrr_ratectl(NULL, ic->ic_bss);
+		wpi_iter_func(sc, ic->ic_bss);
 	else
-		ieee80211_iterate_nodes(ic, wpi_amrr_ratectl, NULL);
+		ieee80211_iterate_nodes(ic, wpi_iter_func, sc);
 
 	timeout_add(&sc->amrr_ch, hz / 2);
 }
 
-/* ARGSUSED */
 void
-wpi_amrr_ratectl(void *arg, struct ieee80211_node *ni)
+wpi_newassoc(struct ieee80211com *ic, struct ieee80211_node *ni, int isnew)
 {
-	struct wpi_amrr *amrr = (struct wpi_amrr *)ni;
-	int need_change = 0;
-
-	if (is_success(amrr) && is_enough(amrr)) {
-		amrr->success++;
-		if (amrr->success >= amrr->success_threshold &&
-		    !is_max_rate(ni)) {
-			amrr->recovery = 1;
-			amrr->success = 0;
-			increase_rate(ni);
-			DPRINTFN(2, ("AMRR increasing rate %d (txcnt=%d "
-			    "retrycnt=%d)\n", ni->ni_txrate, amrr->txcnt,
-			    amrr->retrycnt));
-			need_change = 1;
-		} else {
-			amrr->recovery = 0;
-		}
-	} else if (is_failure(amrr)) {
-		amrr->success = 0;
-		if (!is_min_rate(ni)) {
-			if (amrr->recovery) {
-				amrr->success_threshold *= 2;
-				if (amrr->success_threshold >
-				    WPI_AMRR_MAX_SUCCESS_THRESHOLD)
-					amrr->success_threshold =
-					    WPI_AMRR_MAX_SUCCESS_THRESHOLD;
-			} else {
-				amrr->success_threshold =
-				    WPI_AMRR_MIN_SUCCESS_THRESHOLD;
-			}
-			decrease_rate(ni);
-			DPRINTFN(2, ("AMRR decreasing rate %d (txcnt=%d "
-			    "retrycnt=%d)\n", ni->ni_txrate, amrr->txcnt,
-			    amrr->retrycnt));
-			need_change = 1;
-		}
-		amrr->recovery = 0;	/* paper is incorrect */
-	}
+	struct wpi_softc *sc = ic->ic_if.if_softc;
+	int i;
 
-	if (is_enough(amrr) || need_change)
-		reset_cnt(amrr);
+	ieee80211_amrr_node_init(&sc->amrr, &((struct wpi_node *)ni)->amn);
+
+	/* set rate to some reasonable initial value */
+	for (i = ni->ni_rates.rs_nrates - 1;
+	     i > 0 && (ni->ni_rates.rs_rates[i] & IEEE80211_RATE_VAL) > 72;
+	     i--);
+	ni->ni_txrate = i;
 }
 
 struct cfdriver wpi_cd = {
diff --git a/sys/dev/pci/if_wpireg.h b/sys/dev/pci/if_wpireg.h
index 29a40f534e2..b0acfe5bfca 100644
--- a/sys/dev/pci/if_wpireg.h
+++ b/sys/dev/pci/if_wpireg.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_wpireg.h,v 1.8 2006/06/16 18:54:09 damien Exp $	*/
+/*	$OpenBSD: if_wpireg.h,v 1.9 2006/06/17 19:07:19 damien Exp $	*/
 
 /*-
  * Copyright (c) 2006
@@ -317,7 +317,7 @@ struct wpi_cmd_tsf {
 } __packed;
 
 /* structure for WPI_CMD_ADD_NODE */
-struct wpi_node {
+struct wpi_node_info {
 	uint8_t		control;
 #define WPI_NODE_UPDATE	(1 << 0)
 
diff --git a/sys/dev/pci/if_wpivar.h b/sys/dev/pci/if_wpivar.h
index f80a74426e0..8f3324e90bb 100644
--- a/sys/dev/pci/if_wpivar.h
+++ b/sys/dev/pci/if_wpivar.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_wpivar.h,v 1.6 2006/05/25 09:26:58 damien Exp $	*/
+/*	$OpenBSD: if_wpivar.h,v 1.7 2006/06/17 19:07:19 damien Exp $	*/
 
 /*-
  * Copyright (c) 2006
@@ -91,13 +91,9 @@ struct wpi_rx_ring {
 	int			cur;
 };
 
-struct wpi_amrr {
-	struct	ieee80211_node ni;	/* must be the first */
-	int	txcnt;
-	int	retrycnt;
-	int	success;
-	int	success_threshold;
-	int	recovery;
+struct wpi_node {
+	struct	ieee80211_node		ni;	/* must be the first */
+	struct	ieee80211_amrr_node	amn;
 };
 
 struct wpi_softc {
@@ -106,6 +102,7 @@ struct wpi_softc {
 	struct ieee80211com	sc_ic;
 	int			(*sc_newstate)(struct ieee80211com *,
 				    enum ieee80211_state, int);
+	struct ieee80211_amrr	amrr;
 
 	uint32_t		flags;
 #define WPI_FLAG_FW_INITED	(1 << 0)
diff --git a/sys/dev/usb/if_ral.c b/sys/dev/usb/if_ral.c
index 416596e4418..fab7af4d47c 100644
--- a/sys/dev/usb/if_ral.c
+++ b/sys/dev/usb/if_ral.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_ral.c,v 1.68 2006/06/10 20:28:11 damien Exp $  */
+/*	$OpenBSD: if_ral.c,v 1.69 2006/06/17 19:07:19 damien Exp $  */
 
 /*-
  * Copyright (c) 2005, 2006
@@ -56,7 +56,7 @@
 #include <netinet/ip.h>
 
 #include <net80211/ieee80211_var.h>
-#include <net80211/ieee80211_rssadapt.h>
+#include <net80211/ieee80211_amrr.h>
 #include <net80211/ieee80211_radiotap.h>
 
 #include <dev/usb/usb.h>
@@ -171,8 +171,6 @@ Static void		ural_amrr_start(struct ural_softc *,
 Static void		ural_amrr_timeout(void *);
 Static void		ural_amrr_update(usbd_xfer_handle, usbd_private_handle,
 			    usbd_status status);
-Static void		ural_ratectl(struct ural_amrr *,
-			    struct ieee80211_node *);
 
 /*
  * Supported rates for 802.11a/b/g modes (in 500Kbps unit).
@@ -290,6 +288,9 @@ USB_ATTACH(ural)
 
 	usb_init_task(&sc->sc_task, ural_task, sc);
 	timeout_set(&sc->scan_ch, ural_next_scan, sc);
+
+	sc->amrr.amrr_min_success_threshold =  1;
+	sc->amrr.amrr_max_success_threshold = 10;
 	timeout_set(&sc->amrr_ch, ural_amrr_timeout, sc);
 
 	/* retrieve RT2570 rev. no */
@@ -939,7 +940,7 @@ ural_txtime(int len, int rate, uint32_t flags)
 	uint16_t txtime;
 
 	if (RAL_RATE_IS_OFDM(rate)) {
-		/* IEEE Std 802.11a-1999, pp. 37 */
+		/* IEEE Std 802.11g-2003, pp. 44 */
 		txtime = (8 + 4 * len + 3 + rate - 1) / rate;
 		txtime = 16 + 4 + 4 * txtime + 6;
 	} else {
@@ -2165,28 +2166,20 @@ ural_stop(struct ifnet *ifp, int disable)
 	ural_free_tx_list(sc);
 }
 
-#define URAL_AMRR_MIN_SUCCESS_THRESHOLD	 1
-#define URAL_AMRR_MAX_SUCCESS_THRESHOLD	10
-
 Static void
 ural_amrr_start(struct ural_softc *sc, struct ieee80211_node *ni)
 {
-	struct ural_amrr *amrr = &sc->amrr;
 	int i;
 
 	/* clear statistic registers (STA_CSR0 to STA_CSR10) */
 	ural_read_multi(sc, RAL_STA_CSR0, sc->sta, sizeof sc->sta);
 
-	amrr->success = 0;
-	amrr->recovery = 0;
-	amrr->txcnt = amrr->retrycnt = 0;
-	amrr->success_threshold = URAL_AMRR_MIN_SUCCESS_THRESHOLD;
+	ieee80211_amrr_node_init(&sc->amrr, &sc->amn);
 
 	/* set rate to some reasonable initial value */
 	for (i = ni->ni_rates.rs_nrates - 1;
 	     i > 0 && (ni->ni_rates.rs_rates[i] & IEEE80211_RATE_VAL) > 72;
 	     i--);
-
 	ni->ni_txrate = i;
 
 	timeout_add(&sc->amrr_ch, hz);
@@ -2223,7 +2216,6 @@ ural_amrr_update(usbd_xfer_handle xfer, usbd_private_handle priv,
     usbd_status status)
 {
 	struct ural_softc *sc = (struct ural_softc *)priv;
-	struct ural_amrr *amrr = &sc->amrr;
 	struct ifnet *ifp = &sc->sc_ic.ic_if;
 
 	if (status != USBD_NORMAL_COMPLETION) {
@@ -2235,87 +2227,20 @@ ural_amrr_update(usbd_xfer_handle xfer, usbd_private_handle priv,
 	/* count TX retry-fail as Tx errors */
 	ifp->if_oerrors += sc->sta[9];
 
-	amrr->retrycnt =
+	sc->amn.amn_retrycnt =
 	    sc->sta[7] +	/* TX one-retry ok count */
 	    sc->sta[8] +	/* TX more-retry ok count */
 	    sc->sta[9];		/* TX retry-fail count */
 
-	amrr->txcnt =
-	    amrr->retrycnt +
+	sc->amn.amn_txcnt =
+	    sc->amn.amn_retrycnt +
 	    sc->sta[6];		/* TX no-retry ok count */
 
-	ural_ratectl(amrr, sc->sc_ic.ic_bss);
+	ieee80211_amrr_choose(&sc->amrr, sc->sc_ic.ic_bss, &sc->amn);
 
 	timeout_add(&sc->amrr_ch, hz);
 }
 
-/*-
- * 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
- *
- * This algorithm is particularly well suited for ural since it does not
- * require per-frame retry statistics.  Note however that since h/w does
- * not provide per-frame stats, we can't do per-node rate adaptation and
- * thus automatic rate adaptation is only enabled in STA operating mode.
- */
-#define is_success(amrr)	\
-	((amrr)->retrycnt < (amrr)->txcnt / 10)
-#define is_failure(amrr)	\
-	((amrr)->retrycnt > (amrr)->txcnt / 3)
-#define is_enough(amrr)		\
-	((amrr)->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(amrr)		\
-	do { (amrr)->txcnt = (amrr)->retrycnt = 0; } while (0)
-Static void
-ural_ratectl(struct ural_amrr *amrr, struct ieee80211_node *ni)
-{
-	int need_change = 0;
-
-	if (is_success(amrr) && is_enough(amrr)) {
-		amrr->success++;
-		if (amrr->success >= amrr->success_threshold &&
-		    !is_max_rate(ni)) {
-			amrr->recovery = 1;
-			amrr->success = 0;
-			increase_rate(ni);
-			need_change = 1;
-		} else {
-			amrr->recovery = 0;
-		}
-	} else if (is_failure(amrr)) {
-		amrr->success = 0;
-		if (!is_min_rate(ni)) {
-			if (amrr->recovery) {
-				amrr->success_threshold *= 2;
-				if (amrr->success_threshold >
-				    URAL_AMRR_MAX_SUCCESS_THRESHOLD)
-					amrr->success_threshold =
-					    URAL_AMRR_MAX_SUCCESS_THRESHOLD;
-			} else {
-				amrr->success_threshold =
-				    URAL_AMRR_MIN_SUCCESS_THRESHOLD;
-			}
-			decrease_rate(ni);
-			need_change = 1;
-		}
-		amrr->recovery = 0;	/* original paper was incorrect */
-	}
-
-	if (is_enough(amrr) || need_change)
-		reset_cnt(amrr);
-}
-
 Static int
 ural_activate(device_ptr_t self, enum devact act)
 {
diff --git a/sys/dev/usb/if_ralvar.h b/sys/dev/usb/if_ralvar.h
index ae72dd050dd..28df058f44f 100644
--- a/sys/dev/usb/if_ralvar.h
+++ b/sys/dev/usb/if_ralvar.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_ralvar.h,v 1.5 2006/03/21 11:19:22 pedro Exp $  */
+/*	$OpenBSD: if_ralvar.h,v 1.6 2006/06/17 19:07:19 damien Exp $  */
 
 /*-
  * Copyright (c) 2005
@@ -69,79 +69,72 @@ struct ural_rx_data {
 	struct mbuf		*m;
 };
 
-struct ural_amrr {
-	int	txcnt;
-	int	retrycnt;
-	int	success;
-	int	success_threshold;
-	int	recovery;
-};
-
 struct ural_softc {
-	USBBASEDEVICE		sc_dev;
-	struct ieee80211com	sc_ic;
-	int			(*sc_newstate)(struct ieee80211com *,
-				    enum ieee80211_state, int);
+	USBBASEDEVICE			sc_dev;
+	struct ieee80211com		sc_ic;
+	int				(*sc_newstate)(struct ieee80211com *,
+					    enum ieee80211_state, int);
 
-	usbd_device_handle	sc_udev;
-	usbd_interface_handle	sc_iface;
+	usbd_device_handle		sc_udev;
+	usbd_interface_handle		sc_iface;
 
-	int			sc_rx_no;
-	int			sc_tx_no;
+	int				sc_rx_no;
+	int				sc_tx_no;
 
-	uint32_t		asic_rev;
-	uint16_t		macbbp_rev;
-	uint8_t			rf_rev;
+	uint32_t			asic_rev;
+	uint16_t			macbbp_rev;
+	uint8_t				rf_rev;
 
-	usbd_xfer_handle	amrr_xfer;
+	usbd_xfer_handle		amrr_xfer;
 
-	usbd_pipe_handle	sc_rx_pipeh;
-	usbd_pipe_handle	sc_tx_pipeh;
+	usbd_pipe_handle		sc_rx_pipeh;
+	usbd_pipe_handle		sc_tx_pipeh;
 
-	enum ieee80211_state	sc_state;
-	struct usb_task		sc_task;
+	enum ieee80211_state		sc_state;
+	struct usb_task			sc_task;
 
-	struct ural_amrr	amrr;
+	struct ieee80211_amrr		amrr;
+	struct ieee80211_amrr_node	amn;
 
-	struct ural_rx_data	rx_data[RAL_RX_LIST_COUNT];
-	struct ural_tx_data	tx_data[RAL_TX_LIST_COUNT];
-	int			tx_queued;
+	struct ural_rx_data		rx_data[RAL_RX_LIST_COUNT];
+	struct ural_tx_data		tx_data[RAL_TX_LIST_COUNT];
+	int				tx_queued;
 
-	struct timeout		scan_ch;
-	struct timeout		amrr_ch;
+	struct timeout			scan_ch;
+	struct timeout			amrr_ch;
 
-	int			sc_tx_timer;
+	int				sc_tx_timer;
 
-	uint16_t		sta[11];
-	uint32_t		rf_regs[4];
-	uint8_t			txpow[14];
+	uint16_t			sta[11];
+	uint32_t			rf_regs[4];
+	uint8_t				txpow[14];
 
 	struct {
 		uint8_t	val;
 		uint8_t	reg;
-	} __packed		bbp_prom[16];
+	} __packed			bbp_prom[16];
 
-	int			led_mode;
-	int			hw_radio;
-	int			rx_ant;
-	int			tx_ant;
-	int			nb_ant;
+	int				led_mode;
+	int				hw_radio;
+	int				rx_ant;
+	int				tx_ant;
+	int				nb_ant;
 
 #if NBPFILTER > 0
-	caddr_t			sc_drvbpf;
+	caddr_t				sc_drvbpf;
 
 	union {
 		struct ural_rx_radiotap_header th;
 		uint8_t	pad[64];
-	}			sc_rxtapu;
+	}				sc_rxtapu;
 #define sc_rxtap	sc_rxtapu.th
-	int			sc_rxtap_len;
+	int				sc_rxtap_len;
 
 	union {
 		struct ural_tx_radiotap_header th;
 		uint8_t	pad[64];
-	}			sc_txtapu;
+	}				sc_txtapu;
 #define sc_txtap	sc_txtapu.th
-	int			sc_txtap_len;
+	int				sc_txtap_len;
 #endif
 };
diff --git a/sys/net80211/ieee80211_amrr.c b/sys/net80211/ieee80211_amrr.c
new file mode 100644
index 00000000000..25c6fcd1f2d
--- /dev/null
+++ b/sys/net80211/ieee80211_amrr.c
@@ -0,0 +1,115 @@
+/*	$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/param.h>
+#include <sys/kernel.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.h>
+#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_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 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 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);
+}
diff --git a/sys/net80211/ieee80211_amrr.h b/sys/net80211/ieee80211_amrr.h
new file mode 100644
index 00000000000..5e49b3e9249
--- /dev/null
+++ b/sys/net80211/ieee80211_amrr.h
@@ -0,0 +1,54 @@
+/*	$OpenBSD: ieee80211_amrr.h,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.
+ */
+
+/*-
+ * 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
+ */
+
+/*
+ * Rate control settings.
+ */
+struct ieee80211_amrr {
+	int	amrr_min_success_threshold;
+	int	amrr_max_success_threshold;
+};
+
+#define IEEE80211_AMRR_MIN_SUCCESS_THRESHOLD	 1
+#define IEEE80211_AMRR_MAX_SUCCESS_THRESHOLD	15
+
+/*
+ * Rate control state for a given node.
+ */
+struct ieee80211_amrr_node {
+	int	amn_success;
+	int	amn_recovery;
+	int	amn_success_threshold;
+	int	amn_txcnt;
+	int	amn_retrycnt;
+};
+
+void	ieee80211_amrr_node_init(struct ieee80211_amrr *,
+	    struct ieee80211_amrr_node *);
+void	ieee80211_amrr_choose(struct ieee80211_amrr *, struct ieee80211_node *,
+	    struct ieee80211_amrr_node *);