Add qemu 2.4.0

Change-Id: Ic99cbad4b61f8b127b7dc74d04576c0bcbaaf4f5
Signed-off-by: Yang Zhang <yang.z.zhang@intel.com>

1 files changed, 2828 insertions, 0 deletions

diff --git a/qemu/roms/ipxe/src/net/80211/net80211.c b/qemu/roms/ipxe/src/net/80211/net80211.c
new file mode 100644
index 000000000..434944523
--- /dev/null
+++ b/qemu/roms/ipxe/src/net/80211/net80211.c
@@ -0,0 +1,2828 @@
+/*
+ * The iPXE 802.11 MAC layer.
+ *
+ * Copyright (c) 2009 Joshua Oreman <oremanj@rwcr.net>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <string.h>
+#include <byteswap.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <ipxe/settings.h>
+#include <ipxe/if_arp.h>
+#include <ipxe/ethernet.h>
+#include <ipxe/ieee80211.h>
+#include <ipxe/netdevice.h>
+#include <ipxe/net80211.h>
+#include <ipxe/sec80211.h>
+#include <ipxe/timer.h>
+#include <ipxe/nap.h>
+#include <ipxe/errortab.h>
+#include <ipxe/net80211_err.h>
+
+/** @file
+ *
+ * 802.11 device management
+ */
+
+/** List of 802.11 devices */
+static struct list_head net80211_devices = LIST_HEAD_INIT ( net80211_devices );
+
+/** Set of device operations that does nothing */
+static struct net80211_device_operations net80211_null_ops;
+
+/** Information associated with a received management packet
+ *
+ * This is used to keep beacon signal strengths in a parallel queue to
+ * the beacons themselves.
+ */
+struct net80211_rx_info {
+	int signal;
+	struct list_head list;
+};
+
+/** Context for a probe operation */
+struct net80211_probe_ctx {
+	/** 802.11 device to probe on */
+	struct net80211_device *dev;
+
+	/** Value of keep_mgmt before probe was started */
+	int old_keep_mgmt;
+
+	/** If scanning actively, pointer to probe packet to send */
+	struct io_buffer *probe;
+
+	/** If non-"", the ESSID to limit ourselves to */
+	const char *essid;
+
+	/** Time probe was started */
+	u32 ticks_start;
+
+	/** Time last useful beacon was received */
+	u32 ticks_beacon;
+
+	/** Time channel was last changed */
+	u32 ticks_channel;
+
+	/** Time to stay on each channel */
+	u32 hop_time;
+
+	/** Channels to hop by when changing channel */
+	int hop_step;
+
+	/** List of best beacons for each network found so far */
+	struct list_head *beacons;
+};
+
+/** Context for the association task */
+struct net80211_assoc_ctx {
+	/** Next authentication method to try using */
+	int method;
+
+	/** Time (in ticks) of the last sent association-related packet */
+	int last_packet;
+
+	/** Number of times we have tried sending it */
+	int times_tried;
+};
+
+/**
+ * Detect secure 802.11 network when security support is not available
+ *
+ * @return -ENOTSUP, always.
+ */
+__weak int sec80211_detect ( struct io_buffer *iob __unused,
+			     enum net80211_security_proto *secprot __unused,
+			     enum net80211_crypto_alg *crypt __unused ) {
+	return -ENOTSUP;
+}
+
+/**
+ * @defgroup net80211_netdev Network device interface functions
+ * @{
+ */
+static int net80211_netdev_open ( struct net_device *netdev );
+static void net80211_netdev_close ( struct net_device *netdev );
+static int net80211_netdev_transmit ( struct net_device *netdev,
+				      struct io_buffer *iobuf );
+static void net80211_netdev_poll ( struct net_device *netdev );
+static void net80211_netdev_irq ( struct net_device *netdev, int enable );
+/** @} */
+
+/**
+ * @defgroup net80211_linklayer 802.11 link-layer protocol functions
+ * @{
+ */
+static int net80211_ll_push ( struct net_device *netdev,
+			      struct io_buffer *iobuf, const void *ll_dest,
+			      const void *ll_source, uint16_t net_proto );
+static int net80211_ll_pull ( struct net_device *netdev,
+			      struct io_buffer *iobuf, const void **ll_dest,
+			      const void **ll_source, uint16_t * net_proto,
+			      unsigned int *flags );
+/** @} */
+
+/**
+ * @defgroup net80211_help 802.11 helper functions
+ * @{
+ */
+static void net80211_add_channels ( struct net80211_device *dev, int start,
+				    int len, int txpower );
+static void net80211_filter_hw_channels ( struct net80211_device *dev );
+static void net80211_set_rtscts_rate ( struct net80211_device *dev );
+static int net80211_process_capab ( struct net80211_device *dev,
+				    u16 capab );
+static int net80211_process_ie ( struct net80211_device *dev,
+				 union ieee80211_ie *ie, void *ie_end );
+static union ieee80211_ie *
+net80211_marshal_request_info ( struct net80211_device *dev,
+				union ieee80211_ie *ie );
+/** @} */
+
+/**
+ * @defgroup net80211_assoc_ll 802.11 association handling functions
+ * @{
+ */
+static void net80211_step_associate ( struct net80211_device *dev );
+static void net80211_handle_auth ( struct net80211_device *dev,
+				   struct io_buffer *iob );
+static void net80211_handle_assoc_reply ( struct net80211_device *dev,
+					  struct io_buffer *iob );
+static int net80211_send_disassoc ( struct net80211_device *dev, int reason,
+				    int deauth );
+static void net80211_handle_mgmt ( struct net80211_device *dev,
+				   struct io_buffer *iob, int signal );
+/** @} */
+
+/**
+ * @defgroup net80211_frag 802.11 fragment handling functions
+ * @{
+ */
+static void net80211_free_frags ( struct net80211_device *dev, int fcid );
+static struct io_buffer *net80211_accum_frags ( struct net80211_device *dev,
+						int fcid, int nfrags, int size );
+static void net80211_rx_frag ( struct net80211_device *dev,
+			       struct io_buffer *iob, int signal );
+/** @} */
+
+/**
+ * @defgroup net80211_settings 802.11 settings handlers
+ * @{
+ */
+static int net80211_check_settings_update ( void );
+
+/** 802.11 settings applicator
+ *
+ * When the SSID is changed, this will cause any open devices to
+ * re-associate; when the encryption key is changed, we similarly
+ * update their state.
+ */
+struct settings_applicator net80211_applicator __settings_applicator = {
+	.apply = net80211_check_settings_update,
+};
+
+/** The network name to associate with
+ *
+ * If this is blank, we scan for all networks and use the one with the
+ * greatest signal strength.
+ */
+const struct setting net80211_ssid_setting __setting ( SETTING_NETDEV_EXTRA,
+						       ssid ) = {
+	.name = "ssid",
+	.description = "Wireless SSID",
+	.type = &setting_type_string,
+};
+
+/** Whether to use active scanning
+ *
+ * In order to associate with a hidden SSID, it's necessary to use an
+ * active scan (send probe packets). If this setting is nonzero, an
+ * active scan on the 2.4GHz band will be used to associate.
+ */
+const struct setting net80211_active_setting __setting ( SETTING_NETDEV_EXTRA,
+							 active-scan ) = {
+	.name = "active-scan",
+	.description = "Actively scan for wireless networks",
+	.type = &setting_type_int8,
+};
+
+/** The cryptographic key to use
+ *
+ * For hex WEP keys, as is common, this must be entered using the
+ * normal iPXE method for entering hex settings; an ASCII string of
+ * hex characters will not behave as expected.
+ */
+const struct setting net80211_key_setting __setting ( SETTING_NETDEV_EXTRA,
+						      key ) = {
+	.name = "key",
+	.description = "Wireless encryption key",
+	.type = &setting_type_string,
+};
+
+/** @} */
+
+
+/* ---------- net_device wrapper ---------- */
+
+/**
+ * Open 802.11 device and start association
+ *
+ * @v netdev	Wrapping network device
+ * @ret rc	Return status code
+ *
+ * This sets up a default conservative set of channels for probing,
+ * and starts the auto-association task unless the @c
+ * NET80211_NO_ASSOC flag is set in the wrapped 802.11 device's @c
+ * state field.
+ */
+static int net80211_netdev_open ( struct net_device *netdev )
+{
+	struct net80211_device *dev = netdev->priv;
+	int rc = 0;
+
+	if ( dev->op == &net80211_null_ops )
+		return -EFAULT;
+
+	if ( dev->op->open )
+		rc = dev->op->open ( dev );
+
+	if ( rc < 0 )
+		return rc;
+
+	if ( ! ( dev->state & NET80211_NO_ASSOC ) )
+		net80211_autoassociate ( dev );
+
+	return 0;
+}
+
+/**
+ * Close 802.11 device
+ *
+ * @v netdev	Wrapping network device.
+ *
+ * If the association task is running, this will stop it.
+ */
+static void net80211_netdev_close ( struct net_device *netdev )
+{
+	struct net80211_device *dev = netdev->priv;
+
+	if ( dev->state & NET80211_WORKING )
+		process_del ( &dev->proc_assoc );
+
+	/* Send disassociation frame to AP, to be polite */
+	if ( dev->state & NET80211_ASSOCIATED )
+		net80211_send_disassoc ( dev, IEEE80211_REASON_LEAVING, 0 );
+
+	if ( dev->handshaker && dev->handshaker->stop &&
+	     dev->handshaker->started )
+		dev->handshaker->stop ( dev );
+
+	free ( dev->crypto );
+	free ( dev->handshaker );
+	dev->crypto = NULL;
+	dev->handshaker = NULL;
+
+	netdev_link_down ( netdev );
+	dev->state = 0;
+
+	if ( dev->op->close )
+		dev->op->close ( dev );
+}
+
+/**
+ * Transmit packet on 802.11 device
+ *
+ * @v netdev	Wrapping network device
+ * @v iobuf	I/O buffer
+ * @ret rc	Return status code
+ *
+ * If encryption is enabled for the currently associated network, the
+ * packet will be encrypted prior to transmission.
+ */
+static int net80211_netdev_transmit ( struct net_device *netdev,
+				      struct io_buffer *iobuf )
+{
+	struct net80211_device *dev = netdev->priv;
+	struct ieee80211_frame *hdr = iobuf->data;
+	int rc = -ENOSYS;
+
+	if ( dev->crypto && ! ( hdr->fc & IEEE80211_FC_PROTECTED ) &&
+	     ( ( hdr->fc & IEEE80211_FC_TYPE ) == IEEE80211_TYPE_DATA ) ) {
+		struct io_buffer *niob = dev->crypto->encrypt ( dev->crypto,
+								iobuf );
+		if ( ! niob )
+			return -ENOMEM;	/* only reason encryption could fail */
+
+		/* Free the non-encrypted iob */
+		netdev_tx_complete ( netdev, iobuf );
+
+		/* Transmit the encrypted iob; the Protected flag is
+		   set, so we won't recurse into here again */
+		netdev_tx ( netdev, niob );
+
+		/* Don't transmit the freed packet */
+		return 0;
+	}
+
+	if ( dev->op->transmit )
+		rc = dev->op->transmit ( dev, iobuf );
+
+	return rc;
+}
+
+/**
+ * Poll 802.11 device for received packets and completed transmissions
+ *
+ * @v netdev	Wrapping network device
+ */
+static void net80211_netdev_poll ( struct net_device *netdev )
+{
+	struct net80211_device *dev = netdev->priv;
+
+	if ( dev->op->poll )
+		dev->op->poll ( dev );
+}
+
+/**
+ * Enable or disable interrupts for 802.11 device
+ *
+ * @v netdev	Wrapping network device
+ * @v enable	Whether to enable interrupts
+ */
+static void net80211_netdev_irq ( struct net_device *netdev, int enable )
+{
+	struct net80211_device *dev = netdev->priv;
+
+	if ( dev->op->irq )
+		dev->op->irq ( dev, enable );
+}
+
+/** Network device operations for a wrapped 802.11 device */
+static struct net_device_operations net80211_netdev_ops = {
+	.open = net80211_netdev_open,
+	.close = net80211_netdev_close,
+	.transmit = net80211_netdev_transmit,
+	.poll = net80211_netdev_poll,
+	.irq = net80211_netdev_irq,
+};
+
+
+/* ---------- 802.11 link-layer protocol ---------- */
+
+/**
+ * Determine whether a transmission rate uses ERP/OFDM
+ *
+ * @v rate	Rate in 100 kbps units
+ * @ret is_erp	TRUE if the rate is an ERP/OFDM rate
+ *
+ * 802.11b supports rates of 1.0, 2.0, 5.5, and 11.0 Mbps; any other
+ * rate than these on the 2.4GHz spectrum is an ERP (802.11g) rate.
+ */
+static inline int net80211_rate_is_erp ( u16 rate )
+{
+	if ( rate == 10 || rate == 20 || rate == 55 || rate == 110 )
+		return 0;
+	return 1;
+}
+
+
+/**
+ * Calculate one frame's contribution to 802.11 duration field
+ *
+ * @v dev	802.11 device
+ * @v bytes	Amount of data to calculate duration for
+ * @ret dur	Duration field in microseconds
+ *
+ * To avoid multiple stations attempting to transmit at once, 802.11
+ * provides that every packet shall include a duration field
+ * specifying a length of time for which the wireless medium will be
+ * reserved after it is transmitted. The duration is measured in
+ * microseconds and is calculated with respect to the current
+ * physical-layer parameters of the 802.11 device.
+ *
+ * For an unfragmented data or management frame, or the last fragment
+ * of a fragmented frame, the duration captures only the 10 data bytes
+ * of one ACK; call once with bytes = 10.
+ *
+ * For a fragment of a data or management rame that will be followed
+ * by more fragments, the duration captures an ACK, the following
+ * fragment, and its ACK; add the results of three calls, two with
+ * bytes = 10 and one with bytes set to the next fragment's size.
+ *
+ * For an RTS control frame, the duration captures the responding CTS,
+ * the frame being sent, and its ACK; add the results of three calls,
+ * two with bytes = 10 and one with bytes set to the next frame's size
+ * (assuming unfragmented).
+ *
+ * For a CTS-to-self control frame, the duration captures the frame
+ * being protected and its ACK; add the results of two calls, one with
+ * bytes = 10 and one with bytes set to the next frame's size.
+ *
+ * No other frame types are currently supported by iPXE.
+ */
+u16 net80211_duration ( struct net80211_device *dev, int bytes, u16 rate )
+{
+	struct net80211_channel *chan = &dev->channels[dev->channel];
+	u32 kbps = rate * 100;
+
+	if ( chan->band == NET80211_BAND_5GHZ || net80211_rate_is_erp ( rate ) ) {
+		/* OFDM encoding (802.11a/g) */
+		int bits_per_symbol = ( kbps * 4 ) / 1000;	/* 4us/symbol */
+		int bits = 22 + ( bytes << 3 );	/* 22-bit PLCP */
+		int symbols = ( bits + bits_per_symbol - 1 ) / bits_per_symbol;
+
+		return 16 + 20 + ( symbols * 4 ); /* 16us SIFS, 20us preamble */
+	} else {
+		/* CCK encoding (802.11b) */
+		int phy_time = 144 + 48;	/* preamble + PLCP */
+		int bits = bytes << 3;
+		int data_time = ( bits * 1000 + kbps - 1 ) / kbps;
+
+		if ( dev->phy_flags & NET80211_PHY_USE_SHORT_PREAMBLE )
+			phy_time >>= 1;
+
+		return 10 + phy_time + data_time; /* 10us SIFS */
+	}
+}
+
+/**
+ * Add 802.11 link-layer header
+ *
+ * @v netdev		Wrapping network device
+ * @v iobuf		I/O buffer
+ * @v ll_dest		Link-layer destination address
+ * @v ll_source		Link-layer source address
+ * @v net_proto		Network-layer protocol, in network byte order
+ * @ret rc		Return status code
+ *
+ * This adds both the 802.11 frame header and the 802.2 LLC/SNAP
+ * header used on data packets.
+ *
+ * We also check here for state of the link that would make it invalid
+ * to send a data packet; every data packet must pass through here,
+ * and no non-data packet (e.g. management frame) should.
+ */
+static int net80211_ll_push ( struct net_device *netdev,
+			      struct io_buffer *iobuf, const void *ll_dest,
+			      const void *ll_source, uint16_t net_proto )
+{
+	struct net80211_device *dev = netdev->priv;
+	struct ieee80211_frame *hdr = iob_push ( iobuf,
+						 IEEE80211_LLC_HEADER_LEN +
+						 IEEE80211_TYP_FRAME_HEADER_LEN );
+	struct ieee80211_llc_snap_header *lhdr =
+		( void * ) hdr + IEEE80211_TYP_FRAME_HEADER_LEN;
+
+	/* We can't send data packets if we're not associated. */
+	if ( ! ( dev->state & NET80211_ASSOCIATED ) ) {
+		if ( dev->assoc_rc )
+			return dev->assoc_rc;
+		return -ENETUNREACH;
+	}
+
+	hdr->fc = IEEE80211_THIS_VERSION | IEEE80211_TYPE_DATA |
+	    IEEE80211_STYPE_DATA | IEEE80211_FC_TODS;
+
+	/* We don't send fragmented frames, so duration is the time
+	   for an SIFS + 10-byte ACK. */
+	hdr->duration = net80211_duration ( dev, 10, dev->rates[dev->rate] );
+
+	memcpy ( hdr->addr1, dev->bssid, ETH_ALEN );
+	memcpy ( hdr->addr2, ll_source, ETH_ALEN );
+	memcpy ( hdr->addr3, ll_dest, ETH_ALEN );
+
+	hdr->seq = IEEE80211_MAKESEQ ( ++dev->last_tx_seqnr, 0 );
+
+	lhdr->dsap = IEEE80211_LLC_DSAP;
+	lhdr->ssap = IEEE80211_LLC_SSAP;
+	lhdr->ctrl = IEEE80211_LLC_CTRL;
+	memset ( lhdr->oui, 0x00, 3 );
+	lhdr->ethertype = net_proto;
+
+	return 0;
+}
+
+/**
+ * Remove 802.11 link-layer header
+ *
+ * @v netdev		Wrapping network device
+ * @v iobuf		I/O buffer
+ * @ret ll_dest		Link-layer destination address
+ * @ret ll_source	Link-layer source
+ * @ret net_proto	Network-layer protocol, in network byte order
+ * @ret flags		Packet flags
+ * @ret rc		Return status code
+ *
+ * This expects and removes both the 802.11 frame header and the 802.2
+ * LLC/SNAP header that are used on data packets.
+ */
+static int net80211_ll_pull ( struct net_device *netdev __unused,
+			      struct io_buffer *iobuf,
+			      const void **ll_dest, const void **ll_source,
+			      uint16_t * net_proto, unsigned int *flags )
+{
+	struct ieee80211_frame *hdr = iobuf->data;
+	struct ieee80211_llc_snap_header *lhdr =
+		( void * ) hdr + IEEE80211_TYP_FRAME_HEADER_LEN;
+
+	/* Bunch of sanity checks */
+	if ( iob_len ( iobuf ) < IEEE80211_TYP_FRAME_HEADER_LEN +
+	     IEEE80211_LLC_HEADER_LEN ) {
+		DBGC ( netdev->priv, "802.11 %p packet too short (%zd bytes)\n",
+		       netdev->priv, iob_len ( iobuf ) );
+		return -EINVAL_PKT_TOO_SHORT;
+	}
+
+	if ( ( hdr->fc & IEEE80211_FC_VERSION ) != IEEE80211_THIS_VERSION ) {
+		DBGC ( netdev->priv, "802.11 %p packet invalid version %04x\n",
+		       netdev->priv, hdr->fc & IEEE80211_FC_VERSION );
+		return -EINVAL_PKT_VERSION;
+	}
+
+	if ( ( hdr->fc & IEEE80211_FC_TYPE ) != IEEE80211_TYPE_DATA ||
+	     ( hdr->fc & IEEE80211_FC_SUBTYPE ) != IEEE80211_STYPE_DATA ) {
+		DBGC ( netdev->priv, "802.11 %p packet not data/data (fc=%04x)\n",
+		       netdev->priv, hdr->fc );
+		return -EINVAL_PKT_NOT_DATA;
+	}
+
+	if ( ( hdr->fc & ( IEEE80211_FC_TODS | IEEE80211_FC_FROMDS ) ) !=
+	     IEEE80211_FC_FROMDS ) {
+		DBGC ( netdev->priv, "802.11 %p packet not from DS (fc=%04x)\n",
+		       netdev->priv, hdr->fc );
+		return -EINVAL_PKT_NOT_FROMDS;
+	}
+
+	if ( lhdr->dsap != IEEE80211_LLC_DSAP || lhdr->ssap != IEEE80211_LLC_SSAP ||
+	     lhdr->ctrl != IEEE80211_LLC_CTRL || lhdr->oui[0] || lhdr->oui[1] ||
+	     lhdr->oui[2] ) {
+		DBGC ( netdev->priv, "802.11 %p LLC header is not plain EtherType "
+		       "encapsulator: %02x->%02x [%02x] %02x:%02x:%02x %04x\n",
+		       netdev->priv, lhdr->dsap, lhdr->ssap, lhdr->ctrl,
+		       lhdr->oui[0], lhdr->oui[1], lhdr->oui[2], lhdr->ethertype );
+		return -EINVAL_PKT_LLC_HEADER;
+	}
+
+	iob_pull ( iobuf, sizeof ( *hdr ) + sizeof ( *lhdr ) );
+
+	*ll_dest = hdr->addr1;
+	*ll_source = hdr->addr3;
+	*net_proto = lhdr->ethertype;
+	*flags = ( ( is_multicast_ether_addr ( hdr->addr1 ) ?
+		     LL_MULTICAST : 0 ) |
+		   ( is_broadcast_ether_addr ( hdr->addr1 ) ?
+		     LL_BROADCAST : 0 ) );
+	return 0;
+}
+
+/** 802.11 link-layer protocol */
+static struct ll_protocol net80211_ll_protocol __ll_protocol = {
+	.name = "802.11",
+	.push = net80211_ll_push,
+	.pull = net80211_ll_pull,
+	.init_addr = eth_init_addr,
+	.ntoa = eth_ntoa,
+	.mc_hash = eth_mc_hash,
+	.eth_addr = eth_eth_addr,
+	.eui64 = eth_eui64,
+	.ll_proto = htons ( ARPHRD_ETHER ),	/* "encapsulated Ethernet" */
+	.hw_addr_len = ETH_ALEN,
+	.ll_addr_len = ETH_ALEN,
+	.ll_header_len = IEEE80211_TYP_FRAME_HEADER_LEN +
+				IEEE80211_LLC_HEADER_LEN,
+};
+
+
+/* ---------- 802.11 network management API ---------- */
+
+/**
+ * Get 802.11 device from wrapping network device
+ *
+ * @v netdev	Wrapping network device
+ * @ret dev	802.11 device wrapped by network device, or NULL
+ *
+ * Returns NULL if the network device does not wrap an 802.11 device.
+ */
+struct net80211_device * net80211_get ( struct net_device *netdev )
+{
+	struct net80211_device *dev;
+
+	list_for_each_entry ( dev, &net80211_devices, list ) {
+		if ( netdev->priv == dev )
+			return netdev->priv;
+	}
+
+	return NULL;
+}
+
+/**
+ * Set state of 802.11 device keeping management frames
+ *
+ * @v dev	802.11 device
+ * @v enable	Whether to keep management frames
+ * @ret oldenab	Whether management frames were enabled before this call
+ *
+ * If enable is TRUE, beacon, probe, and action frames will be kept
+ * and may be retrieved by calling net80211_mgmt_dequeue().
+ */
+int net80211_keep_mgmt ( struct net80211_device *dev, int enable )
+{
+	int oldenab = dev->keep_mgmt;
+
+	dev->keep_mgmt = enable;
+	return oldenab;
+}
+
+/**
+ * Get 802.11 management frame
+ *
+ * @v dev	802.11 device
+ * @ret signal	Signal strength of returned management frame
+ * @ret iob	I/O buffer, or NULL if no management frame is queued
+ *
+ * Frames will only be returned by this function if
+ * net80211_keep_mgmt() has been previously called with enable set to
+ * TRUE.
+ *
+ * The calling function takes ownership of the returned I/O buffer.
+ */
+struct io_buffer * net80211_mgmt_dequeue ( struct net80211_device *dev,
+					   int *signal )
+{
+	struct io_buffer *iobuf;
+	struct net80211_rx_info *rxi;
+
+	list_for_each_entry ( rxi, &dev->mgmt_info_queue, list ) {
+		list_del ( &rxi->list );
+		if ( signal )
+			*signal = rxi->signal;
+		free ( rxi );
+
+		assert ( ! list_empty ( &dev->mgmt_queue ) );
+		iobuf = list_first_entry ( &dev->mgmt_queue, struct io_buffer,
+					   list );
+		list_del ( &iobuf->list );
+		return iobuf;
+	}
+
+	return NULL;
+}
+
+/**
+ * Transmit 802.11 management frame
+ *
+ * @v dev	802.11 device
+ * @v fc	Frame Control flags for management frame
+ * @v dest	Destination access point
+ * @v iob	I/O buffer
+ * @ret rc	Return status code
+ *
+ * The @a fc argument must contain at least an IEEE 802.11 management
+ * subtype number (e.g. IEEE80211_STYPE_PROBE_REQ). If it contains
+ * IEEE80211_FC_PROTECTED, the frame will be encrypted prior to
+ * transmission.
+ *
+ * It is required that @a iob have at least 24 bytes of headroom
+ * reserved before its data start.
+ */
+int net80211_tx_mgmt ( struct net80211_device *dev, u16 fc, u8 dest[6],
+		       struct io_buffer *iob )
+{
+	struct ieee80211_frame *hdr = iob_push ( iob,
+						 IEEE80211_TYP_FRAME_HEADER_LEN );
+
+	hdr->fc = IEEE80211_THIS_VERSION | IEEE80211_TYPE_MGMT |
+	    ( fc & ~IEEE80211_FC_PROTECTED );
+	hdr->duration = net80211_duration ( dev, 10, dev->rates[dev->rate] );
+	hdr->seq = IEEE80211_MAKESEQ ( ++dev->last_tx_seqnr, 0 );
+
+	memcpy ( hdr->addr1, dest, ETH_ALEN );	/* DA = RA */
+	memcpy ( hdr->addr2, dev->netdev->ll_addr, ETH_ALEN );	/* SA = TA */
+	memcpy ( hdr->addr3, dest, ETH_ALEN );	/* BSSID */
+
+	if ( fc & IEEE80211_FC_PROTECTED ) {
+		if ( ! dev->crypto )
+			return -EINVAL_CRYPTO_REQUEST;
+
+		struct io_buffer *eiob = dev->crypto->encrypt ( dev->crypto,
+								iob );
+		free_iob ( iob );
+		iob = eiob;
+	}
+
+	return netdev_tx ( dev->netdev, iob );
+}
+
+
+/* ---------- Driver API ---------- */
+
+/** 802.11 association process descriptor */
+static struct process_descriptor net80211_process_desc =
+	PROC_DESC ( struct net80211_device, proc_assoc,
+		    net80211_step_associate );
+
+/**
+ * Allocate 802.11 device
+ *
+ * @v priv_size		Size of driver-private allocation area
+ * @ret dev		Newly allocated 802.11 device
+ *
+ * This function allocates a net_device with space in its private area
+ * for both the net80211_device it will wrap and the driver-private
+ * data space requested. It initializes the link-layer-specific parts
+ * of the net_device, and links the net80211_device to the net_device
+ * appropriately.
+ */
+struct net80211_device * net80211_alloc ( size_t priv_size )
+{
+	struct net80211_device *dev;
+	struct net_device *netdev =
+		alloc_netdev ( sizeof ( *dev ) + priv_size );
+
+	if ( ! netdev )
+		return NULL;
+
+	netdev->ll_protocol = &net80211_ll_protocol;
+	netdev->ll_broadcast = eth_broadcast;
+	netdev->max_pkt_len = IEEE80211_MAX_DATA_LEN;
+	netdev_init ( netdev, &net80211_netdev_ops );
+
+	dev = netdev->priv;
+	dev->netdev = netdev;
+	dev->priv = ( u8 * ) dev + sizeof ( *dev );
+	dev->op = &net80211_null_ops;
+
+	process_init_stopped ( &dev->proc_assoc, &net80211_process_desc,
+			       &netdev->refcnt );
+	INIT_LIST_HEAD ( &dev->mgmt_queue );
+	INIT_LIST_HEAD ( &dev->mgmt_info_queue );
+
+	return dev;
+}
+
+/**
+ * Register 802.11 device with network stack
+ *
+ * @v dev	802.11 device
+ * @v ops	802.11 device operations
+ * @v hw	802.11 hardware information
+ *
+ * This also registers the wrapping net_device with the higher network
+ * layers.
+ */
+int net80211_register ( struct net80211_device *dev,
+			struct net80211_device_operations *ops,
+			struct net80211_hw_info *hw )
+{
+	dev->op = ops;
+	dev->hw = malloc ( sizeof ( *hw ) );
+	if ( ! dev->hw )
+		return -ENOMEM;
+
+	memcpy ( dev->hw, hw, sizeof ( *hw ) );
+	memcpy ( dev->netdev->hw_addr, hw->hwaddr, ETH_ALEN );
+
+	/* Set some sensible channel defaults for driver's open() function */
+	memcpy ( dev->channels, dev->hw->channels,
+		 NET80211_MAX_CHANNELS * sizeof ( dev->channels[0] ) );
+	dev->channel = 0;
+
+	list_add_tail ( &dev->list, &net80211_devices );
+	return register_netdev ( dev->netdev );
+}
+
+/**
+ * Unregister 802.11 device from network stack
+ *
+ * @v dev	802.11 device
+ *
+ * After this call, the device operations are cleared so that they
+ * will not be called.
+ */
+void net80211_unregister ( struct net80211_device *dev )
+{
+	unregister_netdev ( dev->netdev );
+	list_del ( &dev->list );
+	dev->op = &net80211_null_ops;
+}
+
+/**
+ * Free 802.11 device
+ *
+ * @v dev	802.11 device
+ *
+ * The device should be unregistered before this function is called.
+ */
+void net80211_free ( struct net80211_device *dev )
+{
+	free ( dev->hw );
+	rc80211_free ( dev->rctl );
+	netdev_nullify ( dev->netdev );
+	netdev_put ( dev->netdev );
+}
+
+
+/* ---------- 802.11 network management workhorse code ---------- */
+
+/**
+ * Set state of 802.11 device
+ *
+ * @v dev	802.11 device
+ * @v clear	Bitmask of flags to clear
+ * @v set	Bitmask of flags to set
+ * @v status	Status or reason code for most recent operation
+ *
+ * If @a status represents a reason code, it should be OR'ed with
+ * NET80211_IS_REASON.
+ *
+ * Clearing authentication also clears association; clearing
+ * association also clears security handshaking state. Clearing
+ * association removes the link-up flag from the wrapping net_device,
+ * but setting it does not automatically set the flag; that is left to
+ * the judgment of higher-level code.
+ */
+static inline void net80211_set_state ( struct net80211_device *dev,
+					short clear, short set,
+					u16 status )
+{
+	/* The conditions in this function are deliberately formulated
+	   to be decidable at compile-time in most cases. Since clear
+	   and set are generally passed as constants, the body of this
+	   function can be reduced down to a few statements by the
+	   compiler. */
+
+	const int statmsk = NET80211_STATUS_MASK | NET80211_IS_REASON;
+
+	if ( clear & NET80211_PROBED )
+		clear |= NET80211_AUTHENTICATED;
+
+	if ( clear & NET80211_AUTHENTICATED )
+		clear |= NET80211_ASSOCIATED;
+
+	if ( clear & NET80211_ASSOCIATED )
+		clear |= NET80211_CRYPTO_SYNCED;
+
+	dev->state = ( dev->state & ~clear ) | set;
+	dev->state = ( dev->state & ~statmsk ) | ( status & statmsk );
+
+	if ( clear & NET80211_ASSOCIATED )
+		netdev_link_down ( dev->netdev );
+
+	if ( ( clear | set ) & NET80211_ASSOCIATED )
+		dev->op->config ( dev, NET80211_CFG_ASSOC );
+
+	if ( status != 0 ) {
+		if ( status & NET80211_IS_REASON )
+			dev->assoc_rc = -E80211_REASON ( status );
+		else
+			dev->assoc_rc = -E80211_STATUS ( status );
+		netdev_link_err ( dev->netdev, dev->assoc_rc );
+	}
+}
+
+/**
+ * Add channels to 802.11 device
+ *
+ * @v dev	802.11 device
+ * @v start	First channel number to add
+ * @v len	Number of channels to add
+ * @v txpower	TX power (dBm) to allow on added channels
+ *
+ * To replace the current list of channels instead of adding to it,
+ * set the nr_channels field of the 802.11 device to 0 before calling
+ * this function.
+ */
+static void net80211_add_channels ( struct net80211_device *dev, int start,
+				    int len, int txpower )
+{
+	int i, chan = start;
+
+	for ( i = dev->nr_channels; len-- && i < NET80211_MAX_CHANNELS; i++ ) {
+		dev->channels[i].channel_nr = chan;
+		dev->channels[i].maxpower = txpower;
+		dev->channels[i].hw_value = 0;
+
+		if ( chan >= 1 && chan <= 14 ) {
+			dev->channels[i].band = NET80211_BAND_2GHZ;
+			if ( chan == 14 )
+				dev->channels[i].center_freq = 2484;
+			else
+				dev->channels[i].center_freq = 2407 + 5 * chan;
+			chan++;
+		} else {
+			dev->channels[i].band = NET80211_BAND_5GHZ;
+			dev->channels[i].center_freq = 5000 + 5 * chan;
+			chan += 4;
+		}
+	}
+
+	dev->nr_channels = i;
+}
+
+/**
+ * Filter 802.11 device channels for hardware capabilities
+ *
+ * @v dev	802.11 device
+ *
+ * Hardware may support fewer channels than regulatory restrictions
+ * allow; this function filters out channels in dev->channels that are
+ * not supported by the hardware list in dev->hwinfo. It also copies
+ * over the net80211_channel::hw_value and limits maximum TX power
+ * appropriately.
+ *
+ * Channels are matched based on center frequency, ignoring band and
+ * channel number.
+ *
+ * If the driver specifies no supported channels, the effect will be
+ * as though all were supported.
+ */
+static void net80211_filter_hw_channels ( struct net80211_device *dev )
+{
+	int delta = 0, i = 0;
+	int old_freq = dev->channels[dev->channel].center_freq;
+	struct net80211_channel *chan, *hwchan;
+
+	if ( ! dev->hw->nr_channels )
+		return;
+
+	dev->channel = 0;
+	for ( chan = dev->channels; chan < dev->channels + dev->nr_channels;
+	      chan++, i++ ) {
+		int ok = 0;
+		for ( hwchan = dev->hw->channels;
+		      hwchan < dev->hw->channels + dev->hw->nr_channels;
+		      hwchan++ ) {
+			if ( hwchan->center_freq == chan->center_freq ) {
+				ok = 1;
+				break;
+			}
+		}
+
+		if ( ! ok )
+			delta++;
+		else {
+			chan->hw_value = hwchan->hw_value;
+			if ( hwchan->maxpower != 0 &&
+			     chan->maxpower > hwchan->maxpower )
+				chan->maxpower = hwchan->maxpower;
+			if ( old_freq == chan->center_freq )
+				dev->channel = i - delta;
+			if ( delta )
+				chan[-delta] = *chan;
+		}
+	}
+
+	dev->nr_channels -= delta;
+
+	if ( dev->channels[dev->channel].center_freq != old_freq )
+		dev->op->config ( dev, NET80211_CFG_CHANNEL );
+}
+
+/**
+ * Update 802.11 device state to reflect received capabilities field
+ *
+ * @v dev	802.11 device
+ * @v capab	Capabilities field in beacon, probe, or association frame
+ * @ret rc	Return status code
+ */
+static int net80211_process_capab ( struct net80211_device *dev,
+				    u16 capab )
+{
+	u16 old_phy = dev->phy_flags;
+
+	if ( ( capab & ( IEEE80211_CAPAB_MANAGED | IEEE80211_CAPAB_ADHOC ) ) !=
+	     IEEE80211_CAPAB_MANAGED ) {
+		DBGC ( dev, "802.11 %p cannot handle IBSS network\n", dev );
+		return -ENOSYS;
+	}
+
+	dev->phy_flags &= ~( NET80211_PHY_USE_SHORT_PREAMBLE |
+			     NET80211_PHY_USE_SHORT_SLOT );
+
+	if ( capab & IEEE80211_CAPAB_SHORT_PMBL )
+		dev->phy_flags |= NET80211_PHY_USE_SHORT_PREAMBLE;
+
+	if ( capab & IEEE80211_CAPAB_SHORT_SLOT )
+		dev->phy_flags |= NET80211_PHY_USE_SHORT_SLOT;
+
+	if ( old_phy != dev->phy_flags )
+		dev->op->config ( dev, NET80211_CFG_PHY_PARAMS );
+
+	return 0;
+}
+
+/**
+ * Update 802.11 device state to reflect received information elements
+ *
+ * @v dev	802.11 device
+ * @v ie	Pointer to first information element
+ * @v ie_end	Pointer to tail of packet I/O buffer
+ * @ret rc	Return status code
+ */
+static int net80211_process_ie ( struct net80211_device *dev,
+				 union ieee80211_ie *ie, void *ie_end )
+{
+	u16 old_rate = dev->rates[dev->rate];
+	u16 old_phy = dev->phy_flags;
+	int have_rates = 0, i;
+	int ds_channel = 0;
+	int changed = 0;
+	int band = dev->channels[dev->channel].band;
+
+	if ( ! ieee80211_ie_bound ( ie, ie_end ) )
+		return 0;
+
+	for ( ; ie; ie = ieee80211_next_ie ( ie, ie_end ) ) {
+		switch ( ie->id ) {
+		case IEEE80211_IE_SSID:
+			if ( ie->len <= 32 ) {
+				memcpy ( dev->essid, ie->ssid, ie->len );
+				dev->essid[ie->len] = 0;
+			}
+			break;
+
+		case IEEE80211_IE_RATES:
+		case IEEE80211_IE_EXT_RATES:
+			if ( ! have_rates ) {
+				dev->nr_rates = 0;
+				dev->basic_rates = 0;
+				have_rates = 1;
+			}
+			for ( i = 0; i < ie->len &&
+			      dev->nr_rates < NET80211_MAX_RATES; i++ ) {
+				u8 rid = ie->rates[i];
+				u16 rate = ( rid & 0x7f ) * 5;
+
+				if ( rid & 0x80 )
+					dev->basic_rates |=
+						( 1 << dev->nr_rates );
+
+				dev->rates[dev->nr_rates++] = rate;
+			}
+
+			break;
+
+		case IEEE80211_IE_DS_PARAM:
+			if ( dev->channel < dev->nr_channels && ds_channel ==
+			     dev->channels[dev->channel].channel_nr )
+				break;
+			ds_channel = ie->ds_param.current_channel;
+			net80211_change_channel ( dev, ds_channel );
+			break;
+
+		case IEEE80211_IE_COUNTRY:
+			dev->nr_channels = 0;
+
+			DBGC ( dev, "802.11 %p setting country regulations "
+			       "for %c%c\n", dev, ie->country.name[0],
+			       ie->country.name[1] );
+			for ( i = 0; i < ( ie->len - 3 ) / 3; i++ ) {
+				union ieee80211_ie_country_triplet *t =
+					&ie->country.triplet[i];
+				if ( t->first > 200 ) {
+					DBGC ( dev, "802.11 %p ignoring regulatory "
+					       "extension information\n", dev );
+				} else {
+					net80211_add_channels ( dev,
+							t->band.first_channel,
+							t->band.nr_channels,
+							t->band.max_txpower );
+				}
+			}
+			net80211_filter_hw_channels ( dev );
+			break;
+
+		case IEEE80211_IE_ERP_INFO:
+			dev->phy_flags &= ~( NET80211_PHY_USE_PROTECTION |
+					     NET80211_PHY_USE_SHORT_PREAMBLE );
+			if ( ie->erp_info & IEEE80211_ERP_USE_PROTECTION )
+				dev->phy_flags |= NET80211_PHY_USE_PROTECTION;
+			if ( ! ( ie->erp_info & IEEE80211_ERP_BARKER_LONG ) )
+				dev->phy_flags |= NET80211_PHY_USE_SHORT_PREAMBLE;
+			break;
+		}
+	}
+
+	if ( have_rates ) {
+		/* Allow only those rates that are also supported by
+		   the hardware. */
+		int delta = 0, j;
+
+		dev->rate = 0;
+		for ( i = 0; i < dev->nr_rates; i++ ) {
+			int ok = 0;
+			for ( j = 0; j < dev->hw->nr_rates[band]; j++ ) {
+				if ( dev->hw->rates[band][j] == dev->rates[i] ){
+					ok = 1;
+					break;
+				}
+			}
+
+			if ( ! ok )
+				delta++;
+			else {
+				dev->rates[i - delta] = dev->rates[i];
+				if ( old_rate == dev->rates[i] )
+					dev->rate = i - delta;
+			}
+		}
+
+		dev->nr_rates -= delta;
+
+		/* Sort available rates - sorted subclumps tend to already
+		   exist, so insertion sort works well. */
+		for ( i = 1; i < dev->nr_rates; i++ ) {
+			u16 rate = dev->rates[i];
+			u32 tmp, br, mask;
+
+			for ( j = i - 1; j >= 0 && dev->rates[j] >= rate; j-- )
+				dev->rates[j + 1] = dev->rates[j];
+			dev->rates[j + 1] = rate;
+
+			/* Adjust basic_rates to match by rotating the
+			   bits from bit j+1 to bit i left one position. */
+			mask = ( ( 1 << i ) - 1 ) & ~( ( 1 << ( j + 1 ) ) - 1 );
+			br = dev->basic_rates;
+			tmp = br & ( 1 << i );
+			br = ( br & ~( mask | tmp ) ) | ( ( br & mask ) << 1 );
+			br |= ( tmp >> ( i - j - 1 ) );
+			dev->basic_rates = br;
+		}
+
+		net80211_set_rtscts_rate ( dev );
+
+		if ( dev->rates[dev->rate] != old_rate )
+			changed |= NET80211_CFG_RATE;
+	}
+
+	if ( dev->hw->flags & NET80211_HW_NO_SHORT_PREAMBLE )
+		dev->phy_flags &= ~NET80211_PHY_USE_SHORT_PREAMBLE;
+	if ( dev->hw->flags & NET80211_HW_NO_SHORT_SLOT )
+		dev->phy_flags &= ~NET80211_PHY_USE_SHORT_SLOT;
+
+	if ( old_phy != dev->phy_flags )
+		changed |= NET80211_CFG_PHY_PARAMS;
+
+	if ( changed )
+		dev->op->config ( dev, changed );
+
+	return 0;
+}
+
+/**
+ * Create information elements for outgoing probe or association packet
+ *
+ * @v dev		802.11 device
+ * @v ie		Pointer to start of information element area
+ * @ret next_ie		Pointer to first byte after added information elements
+ */
+static union ieee80211_ie *
+net80211_marshal_request_info ( struct net80211_device *dev,
+				union ieee80211_ie *ie )
+{
+	int i;
+
+	ie->id = IEEE80211_IE_SSID;
+	ie->len = strlen ( dev->essid );
+	memcpy ( ie->ssid, dev->essid, ie->len );
+
+	ie = ieee80211_next_ie ( ie, NULL );
+
+	ie->id = IEEE80211_IE_RATES;
+	ie->len = dev->nr_rates;
+	if ( ie->len > 8 )
+		ie->len = 8;
+
+	for ( i = 0; i < ie->len; i++ ) {
+		ie->rates[i] = dev->rates[i] / 5;
+		if ( dev->basic_rates & ( 1 << i ) )
+			ie->rates[i] |= 0x80;
+	}
+
+	ie = ieee80211_next_ie ( ie, NULL );
+
+	if ( dev->rsn_ie && dev->rsn_ie->id == IEEE80211_IE_RSN ) {
+		memcpy ( ie, dev->rsn_ie, dev->rsn_ie->len + 2 );
+		ie = ieee80211_next_ie ( ie, NULL );
+	}
+
+	if ( dev->nr_rates > 8 ) {
+		/* 802.11 requires we use an Extended Basic Rates IE
+		   for the rates beyond the eighth. */
+
+		ie->id = IEEE80211_IE_EXT_RATES;
+		ie->len = dev->nr_rates - 8;
+
+		for ( ; i < dev->nr_rates; i++ ) {
+			ie->rates[i - 8] = dev->rates[i] / 5;
+			if ( dev->basic_rates & ( 1 << i ) )
+				ie->rates[i - 8] |= 0x80;
+		}
+
+		ie = ieee80211_next_ie ( ie, NULL );
+	}
+
+	if ( dev->rsn_ie && dev->rsn_ie->id == IEEE80211_IE_VENDOR ) {
+		memcpy ( ie, dev->rsn_ie, dev->rsn_ie->len + 2 );
+		ie = ieee80211_next_ie ( ie, NULL );
+	}
+
+	return ie;
+}
+
+/** Seconds to wait after finding a network, to possibly find better APs for it
+ *
+ * This is used when a specific SSID to scan for is specified.
+ */
+#define NET80211_PROBE_GATHER    1
+
+/** Seconds to wait after finding a network, to possibly find other networks
+ *
+ * This is used when an empty SSID is specified, to scan for all
+ * networks.
+ */
+#define NET80211_PROBE_GATHER_ALL 2
+
+/** Seconds to allow a probe to take if no network has been found */
+#define NET80211_PROBE_TIMEOUT   6
+
+/**
+ * Begin probe of 802.11 networks
+ *
+ * @v dev	802.11 device
+ * @v essid	SSID to probe for, or "" to accept any (may not be NULL)
+ * @v active	Whether to use active scanning
+ * @ret ctx	Probe context
+ *
+ * Active scanning may only be used on channels 1-11 in the 2.4GHz
+ * band, due to iPXE's lack of a complete regulatory database. If
+ * active scanning is used, probe packets will be sent on each
+ * channel; this can allow association with hidden-SSID networks if
+ * the SSID is properly specified.
+ *
+ * A @c NULL return indicates an out-of-memory condition.
+ *
+ * The returned context must be periodically passed to
+ * net80211_probe_step() until that function returns zero.
+ */
+struct net80211_probe_ctx * net80211_probe_start ( struct net80211_device *dev,
+						   const char *essid,
+						   int active )
+{
+	struct net80211_probe_ctx *ctx = zalloc ( sizeof ( *ctx ) );
+
+	if ( ! ctx )
+		return NULL;
+
+	assert ( netdev_is_open ( dev->netdev ) );
+
+	ctx->dev = dev;
+	ctx->old_keep_mgmt = net80211_keep_mgmt ( dev, 1 );
+	ctx->essid = essid;
+	if ( dev->essid != ctx->essid )
+		strcpy ( dev->essid, ctx->essid );
+
+	if ( active ) {
+		struct ieee80211_probe_req *probe_req;
+		union ieee80211_ie *ie;
+
+		ctx->probe = alloc_iob ( 128 );
+		iob_reserve ( ctx->probe, IEEE80211_TYP_FRAME_HEADER_LEN );
+		probe_req = ctx->probe->data;
+
+		ie = net80211_marshal_request_info ( dev,
+						     probe_req->info_element );
+
+		iob_put ( ctx->probe, ( void * ) ie - ctx->probe->data );
+	}
+
+	ctx->ticks_start = currticks();
+	ctx->ticks_beacon = 0;
+	ctx->ticks_channel = currticks();
+	ctx->hop_time = ticks_per_sec() / ( active ? 2 : 6 );
+
+	/*
+	 * Channels on 2.4GHz overlap, and the most commonly used
+	 * are 1, 6, and 11. We'll get a result faster if we check
+	 * every 5 channels, but in order to hit all of them the
+	 * number of channels must be relatively prime to 5. If it's
+	 * not, tweak the hop.
+	 */
+	ctx->hop_step = 5;
+	while ( dev->nr_channels % ctx->hop_step == 0 && ctx->hop_step > 1 )
+		ctx->hop_step--;
+
+	ctx->beacons = malloc ( sizeof ( *ctx->beacons ) );
+	INIT_LIST_HEAD ( ctx->beacons );
+
+	dev->channel = 0;
+	dev->op->config ( dev, NET80211_CFG_CHANNEL );
+
+	return ctx;
+}
+
+/**
+ * Continue probe of 802.11 networks
+ *
+ * @v ctx	Probe context returned by net80211_probe_start()
+ * @ret rc	Probe status
+ *
+ * The return code will be 0 if the probe is still going on (and this
+ * function should be called again), a positive number if the probe
+ * completed successfully, or a negative error code if the probe
+ * failed for that reason.
+ *
+ * Whether the probe succeeded or failed, you must call
+ * net80211_probe_finish_all() or net80211_probe_finish_best()
+ * (depending on whether you want information on all networks or just
+ * the best-signal one) in order to release the probe context. A
+ * failed probe may still have acquired some valid data.
+ */
+int net80211_probe_step ( struct net80211_probe_ctx *ctx )
+{
+	struct net80211_device *dev = ctx->dev;
+	u32 start_timeout = NET80211_PROBE_TIMEOUT * ticks_per_sec();
+	u32 gather_timeout = ticks_per_sec();
+	u32 now = currticks();
+	struct io_buffer *iob;
+	int signal;
+	int rc;
+	char ssid[IEEE80211_MAX_SSID_LEN + 1];
+
+	gather_timeout *= ( ctx->essid[0] ? NET80211_PROBE_GATHER :
+			    NET80211_PROBE_GATHER_ALL );
+
+	/* Time out if necessary */
+	if ( now >= ctx->ticks_start + start_timeout )
+		return list_empty ( ctx->beacons ) ? -ETIMEDOUT : +1;
+
+	if ( ctx->ticks_beacon > 0 && now >= ctx->ticks_start + gather_timeout )
+		return +1;
+
+	/* Change channels if necessary */
+	if ( now >= ctx->ticks_channel + ctx->hop_time ) {
+		dev->channel = ( dev->channel + ctx->hop_step )
+			% dev->nr_channels;
+		dev->op->config ( dev, NET80211_CFG_CHANNEL );
+		udelay ( dev->hw->channel_change_time );
+
+		ctx->ticks_channel = now;
+
+		if ( ctx->probe ) {
+			struct io_buffer *siob = ctx->probe; /* to send */
+
+			/* make a copy for future use */
+			iob = alloc_iob ( siob->tail - siob->head );
+			iob_reserve ( iob, iob_headroom ( siob ) );
+			memcpy ( iob_put ( iob, iob_len ( siob ) ),
+				 siob->data, iob_len ( siob ) );
+
+			ctx->probe = iob;
+			rc = net80211_tx_mgmt ( dev, IEEE80211_STYPE_PROBE_REQ,
+						eth_broadcast,
+						iob_disown ( siob ) );
+			if ( rc ) {
+				DBGC ( dev, "802.11 %p send probe failed: "
+				       "%s\n", dev, strerror ( rc ) );
+				return rc;
+			}
+		}
+	}
+
+	/* Check for new management packets */
+	while ( ( iob = net80211_mgmt_dequeue ( dev, &signal ) ) != NULL ) {
+		struct ieee80211_frame *hdr;
+		struct ieee80211_beacon *beacon;
+		union ieee80211_ie *ie;
+		struct net80211_wlan *wlan;
+		u16 type;
+
+		hdr = iob->data;
+		type = hdr->fc & IEEE80211_FC_SUBTYPE;
+		beacon = ( struct ieee80211_beacon * ) hdr->data;
+
+		if ( type != IEEE80211_STYPE_BEACON &&
+		     type != IEEE80211_STYPE_PROBE_RESP ) {
+			DBGC2 ( dev, "802.11 %p probe: non-beacon\n", dev );
+			goto drop;
+		}
+
+		if ( ( void * ) beacon->info_element >= iob->tail ) {
+			DBGC ( dev, "802.11 %p probe: beacon with no IEs\n",
+			       dev );
+			goto drop;
+		}
+
+		ie = beacon->info_element;
+
+		if ( ! ieee80211_ie_bound ( ie, iob->tail ) )
+			ie = NULL;
+
+		while ( ie && ie->id != IEEE80211_IE_SSID )
+			ie = ieee80211_next_ie ( ie, iob->tail );
+
+		if ( ! ie ) {
+			DBGC ( dev, "802.11 %p probe: beacon with no SSID\n",
+			       dev );
+			goto drop;
+		}
+
+		memcpy ( ssid, ie->ssid, ie->len );
+		ssid[ie->len] = 0;
+
+		if ( ctx->essid[0] && strcmp ( ctx->essid, ssid ) != 0 ) {
+			DBGC2 ( dev, "802.11 %p probe: beacon with wrong SSID "
+				"(%s)\n", dev, ssid );
+			goto drop;
+		}
+
+		/* See if we've got an entry for this network */
+		list_for_each_entry ( wlan, ctx->beacons, list ) {
+			if ( strcmp ( wlan->essid, ssid ) != 0 )
+				continue;
+
+			if ( signal < wlan->signal ) {
+				DBGC2 ( dev, "802.11 %p probe: beacon for %s "
+					"(%s) with weaker signal %d\n", dev,
+					ssid, eth_ntoa ( hdr->addr3 ), signal );
+				goto drop;
+			}
+
+			goto fill;
+		}
+
+		/* No entry yet - make one */
+		wlan = zalloc ( sizeof ( *wlan ) );
+		strcpy ( wlan->essid, ssid );
+		list_add_tail ( &wlan->list, ctx->beacons );
+
+		/* Whether we're using an old entry or a new one, fill
+		   it with new data. */
+	fill:
+		memcpy ( wlan->bssid, hdr->addr3, ETH_ALEN );
+		wlan->signal = signal;
+		wlan->channel = dev->channels[dev->channel].channel_nr;
+
+		/* Copy this I/O buffer into a new wlan->beacon; the
+		 * iob we've got probably came from the device driver
+		 * and may have the full 2.4k allocation, which we
+		 * don't want to keep around wasting memory.
+		 */
+		free_iob ( wlan->beacon );
+		wlan->beacon = alloc_iob ( iob_len ( iob ) );
+		memcpy ( iob_put ( wlan->beacon, iob_len ( iob ) ),
+			 iob->data, iob_len ( iob ) );
+
+		if ( ( rc = sec80211_detect ( wlan->beacon, &wlan->handshaking,
+					      &wlan->crypto ) ) == -ENOTSUP ) {
+			struct ieee80211_beacon *beacon =
+				( struct ieee80211_beacon * ) hdr->data;
+
+			if ( beacon->capability & IEEE80211_CAPAB_PRIVACY ) {
+				DBG ( "802.11 %p probe: secured network %s but "
+				      "encryption support not compiled in\n",
+				      dev, wlan->essid );
+				wlan->handshaking = NET80211_SECPROT_UNKNOWN;
+				wlan->crypto = NET80211_CRYPT_UNKNOWN;
+			} else {
+				wlan->handshaking = NET80211_SECPROT_NONE;
+				wlan->crypto = NET80211_CRYPT_NONE;
+			}
+		} else if ( rc != 0 ) {
+			DBGC ( dev, "802.11 %p probe warning: network "
+			       "%s with unidentifiable security "
+			       "settings: %s\n", dev, wlan->essid,
+			       strerror ( rc ) );
+		}
+
+		ctx->ticks_beacon = now;
+
+		DBGC2 ( dev, "802.11 %p probe: good beacon for %s (%s)\n",
+			dev, wlan->essid, eth_ntoa ( wlan->bssid ) );
+
+	drop:
+		free_iob ( iob );
+	}
+
+	return 0;
+}
+
+
+/**
+ * Finish probe of 802.11 networks, returning best-signal network found
+ *
+ * @v ctx	Probe context
+ * @ret wlan	Best-signal network found, or @c NULL if none were found
+ *
+ * If net80211_probe_start() was called with a particular SSID
+ * parameter as filter, only a network with that SSID (matching
+ * case-sensitively) can be returned from this function.
+ */
+struct net80211_wlan *
+net80211_probe_finish_best ( struct net80211_probe_ctx *ctx )
+{
+	struct net80211_wlan *best = NULL, *wlan;
+
+	if ( ! ctx )
+		return NULL;
+
+	list_for_each_entry ( wlan, ctx->beacons, list ) {
+		if ( ! best || best->signal < wlan->signal )
+			best = wlan;
+	}
+
+	if ( best )
+		list_del ( &best->list );
+	else
+		DBGC ( ctx->dev, "802.11 %p probe: found nothing for '%s'\n",
+		       ctx->dev, ctx->essid );
+
+	net80211_free_wlanlist ( ctx->beacons );
+
+	net80211_keep_mgmt ( ctx->dev, ctx->old_keep_mgmt );
+
+	if ( ctx->probe )
+		free_iob ( ctx->probe );
+
+	free ( ctx );
+
+	return best;
+}
+
+
+/**
+ * Finish probe of 802.11 networks, returning all networks found
+ *
+ * @v ctx	Probe context
+ * @ret list	List of net80211_wlan detailing networks found
+ *
+ * If net80211_probe_start() was called with a particular SSID
+ * parameter as filter, this will always return either an empty or a
+ * one-element list.
+ */
+struct list_head *net80211_probe_finish_all ( struct net80211_probe_ctx *ctx )
+{
+	struct list_head *beacons = ctx->beacons;
+
+	if ( ! ctx )
+		return NULL;
+
+	net80211_keep_mgmt ( ctx->dev, ctx->old_keep_mgmt );
+
+	if ( ctx->probe )
+		free_iob ( ctx->probe );
+
+	free ( ctx );
+
+	return beacons;
+}
+
+
+/**
+ * Free WLAN structure
+ *
+ * @v wlan	WLAN structure to free
+ */
+void net80211_free_wlan ( struct net80211_wlan *wlan )
+{
+	if ( wlan ) {
+		free_iob ( wlan->beacon );
+		free ( wlan );
+	}
+}
+
+
+/**
+ * Free list of WLAN structures
+ *
+ * @v list	List of WLAN structures to free
+ */
+void net80211_free_wlanlist ( struct list_head *list )
+{
+	struct net80211_wlan *wlan, *tmp;
+
+	if ( ! list )
+		return;
+
+	list_for_each_entry_safe ( wlan, tmp, list, list ) {
+		list_del ( &wlan->list );
+		net80211_free_wlan ( wlan );
+	}
+
+	free ( list );
+}
+
+
+/** Number of ticks to wait for replies to association management frames */
+#define ASSOC_TIMEOUT	TICKS_PER_SEC
+
+/** Number of times to try sending a particular association management frame */
+#define ASSOC_RETRIES	2
+
+/**
+ * Step 802.11 association process
+ *
+ * @v dev	802.11 device
+ */
+static void net80211_step_associate ( struct net80211_device *dev )
+{
+	int rc = 0;
+	int status = dev->state & NET80211_STATUS_MASK;
+
+	/*
+	 * We use a sort of state machine implemented using bits in
+	 * the dev->state variable. At each call, we take the
+	 * logically first step that has not yet succeeded; either it
+	 * has not been tried yet, it's being retried, or it failed.
+	 * If it failed, we return an error indication; otherwise we
+	 * perform the step. If it succeeds, RX handling code will set
+	 * the appropriate status bit for us.
+	 *
+	 * Probe works a bit differently, since we have to step it
+	 * on every call instead of waiting for a packet to arrive
+	 * that will set the completion bit for us.
+	 */
+
+	/* If we're waiting for a reply, check for timeout condition */
+	if ( dev->state & NET80211_WAITING ) {
+		/* Sanity check */
+		if ( ! dev->associating )
+			return;
+
+		if ( currticks() - dev->ctx.assoc->last_packet > ASSOC_TIMEOUT ) {
+			/* Timed out - fail if too many retries, or retry */
+			dev->ctx.assoc->times_tried++;
+			if ( ++dev->ctx.assoc->times_tried > ASSOC_RETRIES ) {
+				rc = -ETIMEDOUT;
+				goto fail;
+			}
+		} else {
+			/* Didn't time out - let it keep going */
+			return;
+		}
+	} else {
+		if ( dev->state & NET80211_PROBED )
+			dev->ctx.assoc->times_tried = 0;
+	}
+
+	if ( ! ( dev->state & NET80211_PROBED ) ) {
+		/* state: probe */
+
+		if ( ! dev->ctx.probe ) {
+			/* start probe */
+			int active = fetch_intz_setting ( NULL,
+						&net80211_active_setting );
+			int band = dev->hw->bands;
+
+			if ( active )
+				band &= ~NET80211_BAND_BIT_5GHZ;
+
+			rc = net80211_prepare_probe ( dev, band, active );
+			if ( rc )
+				goto fail;
+
+			dev->ctx.probe = net80211_probe_start ( dev, dev->essid,
+								active );
+			if ( ! dev->ctx.probe ) {
+				dev->assoc_rc = -ENOMEM;
+				goto fail;
+			}
+		}
+
+		rc = net80211_probe_step ( dev->ctx.probe );
+		if ( ! rc ) {
+			return;	/* still going */
+		}
+
+		dev->associating = net80211_probe_finish_best ( dev->ctx.probe );
+		dev->ctx.probe = NULL;
+		if ( ! dev->associating ) {
+			if ( rc > 0 ) /* "successful" probe found nothing */
+				rc = -ETIMEDOUT;
+			goto fail;
+		}
+
+		/* If we probed using a broadcast SSID, record that
+		   fact for the settings applicator before we clobber
+		   it with the specific SSID we've chosen. */
+		if ( ! dev->essid[0] )
+			dev->state |= NET80211_AUTO_SSID;
+
+		DBGC ( dev, "802.11 %p found network %s (%s)\n", dev,
+		       dev->associating->essid,
+		       eth_ntoa ( dev->associating->bssid ) );
+
+		dev->ctx.assoc = zalloc ( sizeof ( *dev->ctx.assoc ) );
+		if ( ! dev->ctx.assoc ) {
+			rc = -ENOMEM;
+			goto fail;
+		}
+
+		dev->state |= NET80211_PROBED;
+		dev->ctx.assoc->method = IEEE80211_AUTH_OPEN_SYSTEM;
+
+		return;
+	}
+
+	/* Record time of sending the packet we're about to send, for timeout */
+	dev->ctx.assoc->last_packet = currticks();
+
+	if ( ! ( dev->state & NET80211_AUTHENTICATED ) ) {
+		/* state: prepare and authenticate */
+
+		if ( status != IEEE80211_STATUS_SUCCESS ) {
+			/* we tried authenticating already, but failed */
+			int method = dev->ctx.assoc->method;
+
+			if ( method == IEEE80211_AUTH_OPEN_SYSTEM &&
+			     ( status == IEEE80211_STATUS_AUTH_CHALL_INVALID ||
+			       status == IEEE80211_STATUS_AUTH_ALGO_UNSUPP ) ) {
+				/* Maybe this network uses Shared Key? */
+				dev->ctx.assoc->method =
+					IEEE80211_AUTH_SHARED_KEY;
+			} else {
+				goto fail;
+			}
+		}
+
+		DBGC ( dev, "802.11 %p authenticating with method %d\n", dev,
+		       dev->ctx.assoc->method );
+
+		rc = net80211_prepare_assoc ( dev, dev->associating );
+		if ( rc )
+			goto fail;
+
+		rc = net80211_send_auth ( dev, dev->associating,
+					  dev->ctx.assoc->method );
+		if ( rc )
+			goto fail;
+
+		return;
+	}
+
+	if ( ! ( dev->state & NET80211_ASSOCIATED ) ) {
+		/* state: associate */
+
+		if ( status != IEEE80211_STATUS_SUCCESS )
+			goto fail;
+
+		DBGC ( dev, "802.11 %p associating\n", dev );
+
+		if ( dev->handshaker && dev->handshaker->start &&
+		     ! dev->handshaker->started ) {
+			rc = dev->handshaker->start ( dev );
+			if ( rc < 0 )
+				goto fail;
+			dev->handshaker->started = 1;
+		}
+
+		rc = net80211_send_assoc ( dev, dev->associating );
+		if ( rc )
+			goto fail;
+
+		return;
+	}
+
+	if ( ! ( dev->state & NET80211_CRYPTO_SYNCED ) ) {
+		/* state: crypto sync */
+		DBGC ( dev, "802.11 %p security handshaking\n", dev );
+
+		if ( ! dev->handshaker || ! dev->handshaker->step ) {
+			dev->state |= NET80211_CRYPTO_SYNCED;
+			return;
+		}
+
+		rc = dev->handshaker->step ( dev );
+
+		if ( rc < 0 ) {
+			/* Only record the returned error if we're
+			   still marked as associated, because an
+			   asynchronous error will have already been
+			   reported to net80211_deauthenticate() and
+			   assoc_rc thereby set. */
+			if ( dev->state & NET80211_ASSOCIATED )
+				dev->assoc_rc = rc;
+			rc = 0;
+			goto fail;
+		}
+
+		if ( rc > 0 ) {
+			dev->assoc_rc = 0;
+			dev->state |= NET80211_CRYPTO_SYNCED;
+		}
+		return;
+	}
+
+	/* state: done! */
+	netdev_link_up ( dev->netdev );
+	dev->assoc_rc = 0;
+	dev->state &= ~NET80211_WORKING;
+
+	free ( dev->ctx.assoc );
+	dev->ctx.assoc = NULL;
+
+	net80211_free_wlan ( dev->associating );
+	dev->associating = NULL;
+
+	dev->rctl = rc80211_init ( dev );
+
+	process_del ( &dev->proc_assoc );
+
+	DBGC ( dev, "802.11 %p associated with %s (%s)\n", dev,
+	       dev->essid, eth_ntoa ( dev->bssid ) );
+
+	return;
+
+ fail:
+	dev->state &= ~( NET80211_WORKING | NET80211_WAITING );
+	if ( rc )
+		dev->assoc_rc = rc;
+
+	netdev_link_err ( dev->netdev, dev->assoc_rc );
+
+	/* We never reach here from the middle of a probe, so we don't
+	   need to worry about freeing dev->ctx.probe. */
+
+	if ( dev->state & NET80211_PROBED ) {
+		free ( dev->ctx.assoc );
+		dev->ctx.assoc = NULL;
+	}
+
+	net80211_free_wlan ( dev->associating );
+	dev->associating = NULL;
+
+	process_del ( &dev->proc_assoc );
+
+	DBGC ( dev, "802.11 %p association failed (state=%04x): "
+	       "%s\n", dev, dev->state, strerror ( dev->assoc_rc ) );
+
+	/* Try it again: */
+	net80211_autoassociate ( dev );
+}
+
+/**
+ * Check for 802.11 SSID or key updates
+ *
+ * This acts as a settings applicator; if the user changes netX/ssid,
+ * and netX is currently open, the association task will be invoked
+ * again. If the user changes the encryption key, the current security
+ * handshaker will be asked to update its state to match; if that is
+ * impossible without reassociation, we reassociate.
+ */
+static int net80211_check_settings_update ( void )
+{
+	struct net80211_device *dev;
+	char ssid[IEEE80211_MAX_SSID_LEN + 1];
+	int key_reassoc;
+
+	list_for_each_entry ( dev, &net80211_devices, list ) {
+		if ( ! netdev_is_open ( dev->netdev ) )
+			continue;
+
+		key_reassoc = 0;
+		if ( dev->handshaker && dev->handshaker->change_key &&
+		     dev->handshaker->change_key ( dev ) < 0 )
+			key_reassoc = 1;
+
+		fetch_string_setting ( netdev_settings ( dev->netdev ),
+				       &net80211_ssid_setting, ssid,
+				       IEEE80211_MAX_SSID_LEN + 1 );
+
+		if ( key_reassoc ||
+		     ( ! ( ! ssid[0] && ( dev->state & NET80211_AUTO_SSID ) ) &&
+		       strcmp ( ssid, dev->essid ) != 0 ) ) {
+			DBGC ( dev, "802.11 %p updating association: "
+			       "%s -> %s\n", dev, dev->essid, ssid );
+			net80211_autoassociate ( dev );
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * Start 802.11 association process
+ *
+ * @v dev	802.11 device
+ *
+ * If the association process is running, it will be restarted.
+ */
+void net80211_autoassociate ( struct net80211_device *dev )
+{
+	if ( ! ( dev->state & NET80211_WORKING ) ) {
+		DBGC2 ( dev, "802.11 %p spawning association process\n", dev );
+		process_add ( &dev->proc_assoc );
+	} else {
+		DBGC2 ( dev, "802.11 %p restarting association\n", dev );
+	}
+
+	/* Clean up everything an earlier association process might
+	   have been in the middle of using */
+	if ( dev->associating )
+		net80211_free_wlan ( dev->associating );
+
+	if ( ! ( dev->state & NET80211_PROBED ) )
+		net80211_free_wlan (
+			net80211_probe_finish_best ( dev->ctx.probe ) );
+	else
+		free ( dev->ctx.assoc );
+
+	/* Reset to a clean state */
+	fetch_string_setting ( netdev_settings ( dev->netdev ),
+			       &net80211_ssid_setting, dev->essid,
+			       IEEE80211_MAX_SSID_LEN + 1 );
+	dev->ctx.probe = NULL;
+	dev->associating = NULL;
+	dev->assoc_rc = 0;
+	net80211_set_state ( dev, NET80211_PROBED, NET80211_WORKING, 0 );
+}
+
+/**
+ * Pick TX rate for RTS/CTS packets based on data rate
+ *
+ * @v dev	802.11 device
+ *
+ * The RTS/CTS rate is the fastest TX rate marked as "basic" that is
+ * not faster than the data rate.
+ */
+static void net80211_set_rtscts_rate ( struct net80211_device *dev )
+{
+	u16 datarate = dev->rates[dev->rate];
+	u16 rtsrate = 0;
+	int rts_idx = -1;
+	int i;
+
+	for ( i = 0; i < dev->nr_rates; i++ ) {
+		u16 rate = dev->rates[i];
+
+		if ( ! ( dev->basic_rates & ( 1 << i ) ) || rate > datarate )
+			continue;
+
+		if ( rate > rtsrate ) {
+			rtsrate = rate;
+			rts_idx = i;
+		}
+	}
+
+	/* If this is in initialization, we might not have any basic
+	   rates; just use the first data rate in that case. */
+	if ( rts_idx < 0 )
+		rts_idx = 0;
+
+	dev->rtscts_rate = rts_idx;
+}
+
+/**
+ * Set data transmission rate for 802.11 device
+ *
+ * @v dev	802.11 device
+ * @v rate	Rate to set, as index into @c dev->rates array
+ */
+void net80211_set_rate_idx ( struct net80211_device *dev, int rate )
+{
+	assert ( netdev_is_open ( dev->netdev ) );
+
+	if ( rate >= 0 && rate < dev->nr_rates && rate != dev->rate ) {
+		DBGC2 ( dev, "802.11 %p changing rate from %d->%d Mbps\n",
+			dev, dev->rates[dev->rate] / 10,
+			dev->rates[rate] / 10 );
+
+		dev->rate = rate;
+		net80211_set_rtscts_rate ( dev );
+		dev->op->config ( dev, NET80211_CFG_RATE );
+	}
+}
+
+/**
+ * Configure 802.11 device to transmit on a certain channel
+ *
+ * @v dev	802.11 device
+ * @v channel	Channel number (1-11 for 2.4GHz) to transmit on
+ */
+int net80211_change_channel ( struct net80211_device *dev, int channel )
+{
+	int i, oldchan = dev->channel;
+
+	assert ( netdev_is_open ( dev->netdev ) );
+
+	for ( i = 0; i < dev->nr_channels; i++ ) {
+		if ( dev->channels[i].channel_nr == channel ) {
+			dev->channel = i;
+			break;
+		}
+	}
+
+	if ( i == dev->nr_channels )
+		return -ENOENT;
+
+	if ( i != oldchan )
+		return dev->op->config ( dev, NET80211_CFG_CHANNEL );
+
+	return 0;
+}
+
+/**
+ * Prepare 802.11 device channel and rate set for scanning
+ *
+ * @v dev	802.11 device
+ * @v band	RF band(s) on which to prepare for scanning
+ * @v active	Whether the scanning will be active
+ * @ret rc	Return status code
+ */
+int net80211_prepare_probe ( struct net80211_device *dev, int band,
+			     int active )
+{
+	assert ( netdev_is_open ( dev->netdev ) );
+
+	if ( active && ( band & NET80211_BAND_BIT_5GHZ ) ) {
+		DBGC ( dev, "802.11 %p cannot perform active scanning on "
+		       "5GHz band\n", dev );
+		return -EINVAL_ACTIVE_SCAN;
+	}
+
+	if ( band == 0 ) {
+		/* This can happen for a 5GHz-only card with 5GHz
+		   scanning masked out by an active request. */
+		DBGC ( dev, "802.11 %p asked to prepare for scanning nothing\n",
+		       dev );
+		return -EINVAL_ACTIVE_SCAN;
+	}
+
+	dev->nr_channels = 0;
+
+	if ( active )
+		net80211_add_channels ( dev, 1, 11, NET80211_REG_TXPOWER );
+	else {
+		if ( band & NET80211_BAND_BIT_2GHZ )
+			net80211_add_channels ( dev, 1, 14,
+						NET80211_REG_TXPOWER );
+		if ( band & NET80211_BAND_BIT_5GHZ )
+			net80211_add_channels ( dev, 36, 8,
+						NET80211_REG_TXPOWER );
+	}
+
+	net80211_filter_hw_channels ( dev );
+
+	/* Use channel 1 for now */
+	dev->channel = 0;
+	dev->op->config ( dev, NET80211_CFG_CHANNEL );
+
+	/* Always do active probes at lowest (presumably first) speed */
+	dev->rate = 0;
+	dev->nr_rates = 1;
+	dev->rates[0] = dev->hw->rates[dev->channels[0].band][0];
+	dev->op->config ( dev, NET80211_CFG_RATE );
+
+	return 0;
+}
+
+/**
+ * Prepare 802.11 device channel and rate set for communication
+ *
+ * @v dev	802.11 device
+ * @v wlan	WLAN to prepare for communication with
+ * @ret rc	Return status code
+ */
+int net80211_prepare_assoc ( struct net80211_device *dev,
+			     struct net80211_wlan *wlan )
+{
+	struct ieee80211_frame *hdr = wlan->beacon->data;
+	struct ieee80211_beacon *beacon =
+		( struct ieee80211_beacon * ) hdr->data;
+	struct net80211_handshaker *handshaker;
+	int rc;
+
+	assert ( netdev_is_open ( dev->netdev ) );
+
+	net80211_set_state ( dev, NET80211_ASSOCIATED, 0, 0 );
+	memcpy ( dev->bssid, wlan->bssid, ETH_ALEN );
+	strcpy ( dev->essid, wlan->essid );
+
+	free ( dev->rsn_ie );
+	dev->rsn_ie = NULL;
+
+	dev->last_beacon_timestamp = beacon->timestamp;
+	dev->tx_beacon_interval = 1024 * beacon->beacon_interval;
+
+	/* Barring an IE that tells us the channel outright, assume
+	   the channel we heard this AP best on is the channel it's
+	   communicating on. */
+	net80211_change_channel ( dev, wlan->channel );
+
+	rc = net80211_process_capab ( dev, beacon->capability );
+	if ( rc )
+		return rc;
+
+	rc = net80211_process_ie ( dev, beacon->info_element,
+				   wlan->beacon->tail );
+	if ( rc )
+		return rc;
+
+	/* Associate at the lowest rate so we know it'll get through */
+	dev->rate = 0;
+	dev->op->config ( dev, NET80211_CFG_RATE );
+
+	/* Free old handshaker and crypto, if they exist */
+	if ( dev->handshaker && dev->handshaker->stop &&
+	     dev->handshaker->started )
+		dev->handshaker->stop ( dev );
+	free ( dev->handshaker );
+	dev->handshaker = NULL;
+	free ( dev->crypto );
+	free ( dev->gcrypto );
+	dev->crypto = dev->gcrypto = NULL;
+
+	/* Find new security handshaker to use */
+	for_each_table_entry ( handshaker, NET80211_HANDSHAKERS ) {
+		if ( handshaker->protocol == wlan->handshaking ) {
+			dev->handshaker = zalloc ( sizeof ( *handshaker ) +
+						   handshaker->priv_len );
+			if ( ! dev->handshaker )
+				return -ENOMEM;
+
+			memcpy ( dev->handshaker, handshaker,
+				 sizeof ( *handshaker ) );
+			dev->handshaker->priv = ( ( void * ) dev->handshaker +
+						  sizeof ( *handshaker ) );
+			break;
+		}
+	}
+
+	if ( ( wlan->handshaking != NET80211_SECPROT_NONE ) &&
+	     ! dev->handshaker ) {
+		DBGC ( dev, "802.11 %p no support for handshaking scheme %d\n",
+		       dev, wlan->handshaking );
+		return -( ENOTSUP | ( wlan->handshaking << 8 ) );
+	}
+
+	/* Initialize security handshaker */
+	if ( dev->handshaker ) {
+		rc = dev->handshaker->init ( dev );
+		if ( rc < 0 )
+			return rc;
+	}
+
+	return 0;
+}
+
+/**
+ * Send 802.11 initial authentication frame
+ *
+ * @v dev	802.11 device
+ * @v wlan	WLAN to authenticate with
+ * @v method	Authentication method
+ * @ret rc	Return status code
+ *
+ * @a method may be 0 for Open System authentication or 1 for Shared
+ * Key authentication. Open System provides no security in association
+ * whatsoever, relying on encryption for confidentiality, but Shared
+ * Key actively introduces security problems and is very rarely used.
+ */
+int net80211_send_auth ( struct net80211_device *dev,
+			 struct net80211_wlan *wlan, int method )
+{
+	struct io_buffer *iob = alloc_iob ( 64 );
+	struct ieee80211_auth *auth;
+
+	net80211_set_state ( dev, 0, NET80211_WAITING, 0 );
+	iob_reserve ( iob, IEEE80211_TYP_FRAME_HEADER_LEN );
+	auth = iob_put ( iob, sizeof ( *auth ) );
+	auth->algorithm = method;
+	auth->tx_seq = 1;
+	auth->status = 0;
+
+	return net80211_tx_mgmt ( dev, IEEE80211_STYPE_AUTH, wlan->bssid, iob );
+}
+
+/**
+ * Handle receipt of 802.11 authentication frame
+ *
+ * @v dev	802.11 device
+ * @v iob	I/O buffer
+ *
+ * If the authentication method being used is Shared Key, and the
+ * frame that was received included challenge text, the frame is
+ * encrypted using the cryptosystem currently in effect and sent back
+ * to the AP to complete the authentication.
+ */
+static void net80211_handle_auth ( struct net80211_device *dev,
+				   struct io_buffer *iob )
+{
+	struct ieee80211_frame *hdr = iob->data;
+	struct ieee80211_auth *auth =
+	    ( struct ieee80211_auth * ) hdr->data;
+
+	if ( auth->tx_seq & 1 ) {
+		DBGC ( dev, "802.11 %p authentication received improperly "
+		       "directed frame (seq. %d)\n", dev, auth->tx_seq );
+		net80211_set_state ( dev, NET80211_WAITING, 0,
+				     IEEE80211_STATUS_FAILURE );
+		return;
+	}
+
+	if ( auth->status != IEEE80211_STATUS_SUCCESS ) {
+		DBGC ( dev, "802.11 %p authentication failed: status %d\n",
+		       dev, auth->status );
+		net80211_set_state ( dev, NET80211_WAITING, 0,
+				     auth->status );
+		return;
+	}
+
+	if ( auth->algorithm == IEEE80211_AUTH_SHARED_KEY && ! dev->crypto ) {
+		DBGC ( dev, "802.11 %p can't perform shared-key authentication "
+		       "without a cryptosystem\n", dev );
+		net80211_set_state ( dev, NET80211_WAITING, 0,
+				     IEEE80211_STATUS_FAILURE );
+		return;
+	}
+
+	if ( auth->algorithm == IEEE80211_AUTH_SHARED_KEY &&
+	     auth->tx_seq == 2 ) {
+		/* Since the iob we got is going to be freed as soon
+		   as we return, we can do some in-place
+		   modification. */
+		auth->tx_seq = 3;
+		auth->status = 0;
+
+		memcpy ( hdr->addr2, hdr->addr1, ETH_ALEN );
+		memcpy ( hdr->addr1, hdr->addr3, ETH_ALEN );
+
+		netdev_tx ( dev->netdev,
+			    dev->crypto->encrypt ( dev->crypto, iob ) );
+		return;
+	}
+
+	net80211_set_state ( dev, NET80211_WAITING, NET80211_AUTHENTICATED,
+			     IEEE80211_STATUS_SUCCESS );
+
+	return;
+}
+
+/**
+ * Send 802.11 association frame
+ *
+ * @v dev	802.11 device
+ * @v wlan	WLAN to associate with
+ * @ret rc	Return status code
+ */
+int net80211_send_assoc ( struct net80211_device *dev,
+			  struct net80211_wlan *wlan )
+{
+	struct io_buffer *iob = alloc_iob ( 128 );
+	struct ieee80211_assoc_req *assoc;
+	union ieee80211_ie *ie;
+
+	net80211_set_state ( dev, 0, NET80211_WAITING, 0 );
+
+	iob_reserve ( iob, IEEE80211_TYP_FRAME_HEADER_LEN );
+	assoc = iob->data;
+
+	assoc->capability = IEEE80211_CAPAB_MANAGED;
+	if ( ! ( dev->hw->flags & NET80211_HW_NO_SHORT_PREAMBLE ) )
+		assoc->capability |= IEEE80211_CAPAB_SHORT_PMBL;
+	if ( ! ( dev->hw->flags & NET80211_HW_NO_SHORT_SLOT ) )
+		assoc->capability |= IEEE80211_CAPAB_SHORT_SLOT;
+	if ( wlan->crypto )
+		assoc->capability |= IEEE80211_CAPAB_PRIVACY;
+
+	assoc->listen_interval = 1;
+
+	ie = net80211_marshal_request_info ( dev, assoc->info_element );
+
+	DBGP ( "802.11 %p about to send association request:\n", dev );
+	DBGP_HD ( iob->data, ( void * ) ie - iob->data );
+
+	iob_put ( iob, ( void * ) ie - iob->data );
+
+	return net80211_tx_mgmt ( dev, IEEE80211_STYPE_ASSOC_REQ,
+				  wlan->bssid, iob );
+}
+
+/**
+ * Handle receipt of 802.11 association reply frame
+ *
+ * @v dev	802.11 device
+ * @v iob	I/O buffer
+ */
+static void net80211_handle_assoc_reply ( struct net80211_device *dev,
+					  struct io_buffer *iob )
+{
+	struct ieee80211_frame *hdr = iob->data;
+	struct ieee80211_assoc_resp *assoc =
+		( struct ieee80211_assoc_resp * ) hdr->data;
+
+	net80211_process_capab ( dev, assoc->capability );
+	net80211_process_ie ( dev, assoc->info_element, iob->tail );
+
+	if ( assoc->status != IEEE80211_STATUS_SUCCESS ) {
+		DBGC ( dev, "802.11 %p association failed: status %d\n",
+		       dev, assoc->status );
+		net80211_set_state ( dev, NET80211_WAITING, 0,
+				     assoc->status );
+		return;
+	}
+
+	/* ESSID was filled before the association request was sent */
+	memcpy ( dev->bssid, hdr->addr3, ETH_ALEN );
+	dev->aid = assoc->aid;
+
+	net80211_set_state ( dev, NET80211_WAITING, NET80211_ASSOCIATED,
+			     IEEE80211_STATUS_SUCCESS );
+}
+
+
+/**
+ * Send 802.11 disassociation frame
+ *
+ * @v dev	802.11 device
+ * @v reason	Reason for disassociation
+ * @v deauth	If TRUE, send deauthentication instead of disassociation
+ * @ret rc	Return status code
+ */
+static int net80211_send_disassoc ( struct net80211_device *dev, int reason,
+				    int deauth )
+{
+	struct io_buffer *iob = alloc_iob ( 64 );
+	struct ieee80211_disassoc *disassoc;
+
+	if ( ! ( dev->state & NET80211_ASSOCIATED ) )
+		return -EINVAL;
+
+	net80211_set_state ( dev, NET80211_ASSOCIATED, 0, 0 );
+	iob_reserve ( iob, IEEE80211_TYP_FRAME_HEADER_LEN );
+	disassoc = iob_put ( iob, sizeof ( *disassoc ) );
+	disassoc->reason = reason;
+
+	return net80211_tx_mgmt ( dev, deauth ? IEEE80211_STYPE_DEAUTH :
+				  IEEE80211_STYPE_DISASSOC, dev->bssid, iob );
+}
+
+
+/**
+ * Deauthenticate from current network and try again
+ *
+ * @v dev	802.11 device
+ * @v rc	Return status code indicating reason
+ *
+ * The deauthentication will be sent using an 802.11 "unspecified
+ * reason", as is common, but @a rc will be set as a link-up
+ * error to aid the user in debugging.
+ */
+void net80211_deauthenticate ( struct net80211_device *dev, int rc )
+{
+	net80211_send_disassoc ( dev, IEEE80211_REASON_UNSPECIFIED, 1 );
+	dev->assoc_rc = rc;
+	netdev_link_err ( dev->netdev, rc );
+
+	net80211_autoassociate ( dev );
+}
+
+
+/** Smoothing factor (1-7) for link quality calculation */
+#define LQ_SMOOTH	7
+
+/**
+ * Update link quality information based on received beacon
+ *
+ * @v dev	802.11 device
+ * @v iob	I/O buffer containing beacon
+ * @ret rc	Return status code
+ */
+static void net80211_update_link_quality ( struct net80211_device *dev,
+					   struct io_buffer *iob )
+{
+	struct ieee80211_frame *hdr = iob->data;
+	struct ieee80211_beacon *beacon;
+	u32 dt, rxi;
+
+	if ( ! ( dev->state & NET80211_ASSOCIATED ) )
+		return;
+
+	beacon = ( struct ieee80211_beacon * ) hdr->data;
+	dt = ( u32 ) ( beacon->timestamp - dev->last_beacon_timestamp );
+	rxi = dev->rx_beacon_interval;
+
+	rxi = ( LQ_SMOOTH * rxi ) + ( ( 8 - LQ_SMOOTH ) * dt );
+	dev->rx_beacon_interval = rxi >> 3;
+
+	dev->last_beacon_timestamp = beacon->timestamp;
+}
+
+
+/**
+ * Handle receipt of 802.11 management frame
+ *
+ * @v dev	802.11 device
+ * @v iob	I/O buffer
+ * @v signal	Signal strength of received frame
+ */
+static void net80211_handle_mgmt ( struct net80211_device *dev,
+				   struct io_buffer *iob, int signal )
+{
+	struct ieee80211_frame *hdr = iob->data;
+	struct ieee80211_disassoc *disassoc;
+	u16 stype = hdr->fc & IEEE80211_FC_SUBTYPE;
+	int keep = 0;
+	int is_deauth = ( stype == IEEE80211_STYPE_DEAUTH );
+
+	if ( ( hdr->fc & IEEE80211_FC_TYPE ) != IEEE80211_TYPE_MGMT ) {
+		free_iob ( iob );
+		return;		/* only handle management frames */
+	}
+
+	switch ( stype ) {
+		/* We reconnect on deauthentication and disassociation. */
+	case IEEE80211_STYPE_DEAUTH:
+	case IEEE80211_STYPE_DISASSOC:
+		disassoc = ( struct ieee80211_disassoc * ) hdr->data;
+		net80211_set_state ( dev, is_deauth ? NET80211_AUTHENTICATED :
+				     NET80211_ASSOCIATED, 0,
+				     NET80211_IS_REASON | disassoc->reason );
+		DBGC ( dev, "802.11 %p %s: reason %d\n",
+		       dev, is_deauth ? "deauthenticated" : "disassociated",
+		       disassoc->reason );
+
+		/* Try to reassociate, in case it's transient. */
+		net80211_autoassociate ( dev );
+
+		break;
+
+		/* We handle authentication and association. */
+	case IEEE80211_STYPE_AUTH:
+		if ( ! ( dev->state & NET80211_AUTHENTICATED ) )
+			net80211_handle_auth ( dev, iob );
+		break;
+
+	case IEEE80211_STYPE_ASSOC_RESP:
+	case IEEE80211_STYPE_REASSOC_RESP:
+		if ( ! ( dev->state & NET80211_ASSOCIATED ) )
+			net80211_handle_assoc_reply ( dev, iob );
+		break;
+
+		/* We pass probes and beacons onto network scanning
+		   code. Pass actions for future extensibility. */
+	case IEEE80211_STYPE_BEACON:
+		net80211_update_link_quality ( dev, iob );
+		/* fall through */
+	case IEEE80211_STYPE_PROBE_RESP:
+	case IEEE80211_STYPE_ACTION:
+		if ( dev->keep_mgmt ) {
+			struct net80211_rx_info *rxinf;
+			rxinf = zalloc ( sizeof ( *rxinf ) );
+			if ( ! rxinf ) {
+				DBGC ( dev, "802.11 %p out of memory\n", dev );
+				break;
+			}
+			rxinf->signal = signal;
+			list_add_tail ( &iob->list, &dev->mgmt_queue );
+			list_add_tail ( &rxinf->list, &dev->mgmt_info_queue );
+			keep = 1;
+		}
+		break;
+
+	case IEEE80211_STYPE_PROBE_REQ:
+		/* Some nodes send these broadcast. Ignore them. */
+		break;
+
+	case IEEE80211_STYPE_ASSOC_REQ:
+	case IEEE80211_STYPE_REASSOC_REQ:
+		/* We should never receive these, only send them. */
+		DBGC ( dev, "802.11 %p received strange management request "
+		       "(%04x)\n", dev, stype );
+		break;
+
+	default:
+		DBGC ( dev, "802.11 %p received unimplemented management "
+		       "packet (%04x)\n", dev, stype );
+		break;
+	}
+
+	if ( ! keep )
+		free_iob ( iob );
+}
+
+/* ---------- Packet handling functions ---------- */
+
+/**
+ * Free buffers used by 802.11 fragment cache entry
+ *
+ * @v dev	802.11 device
+ * @v fcid	Fragment cache entry index
+ *
+ * After this function, the referenced entry will be marked unused.
+ */
+static void net80211_free_frags ( struct net80211_device *dev, int fcid )
+{
+	int j;
+	struct net80211_frag_cache *frag = &dev->frags[fcid];
+
+	for ( j = 0; j < 16; j++ ) {
+		if ( frag->iob[j] ) {
+			free_iob ( frag->iob[j] );
+			frag->iob[j] = NULL;
+		}
+	}
+
+	frag->seqnr = 0;
+	frag->start_ticks = 0;
+	frag->in_use = 0;
+}
+
+/**
+ * Accumulate 802.11 fragments into one I/O buffer
+ *
+ * @v dev	802.11 device
+ * @v fcid	Fragment cache entry index
+ * @v nfrags	Number of fragments received
+ * @v size	Sum of sizes of all fragments, including headers
+ * @ret iob	I/O buffer containing reassembled packet
+ *
+ * This function does not free the fragment buffers.
+ */
+static struct io_buffer *net80211_accum_frags ( struct net80211_device *dev,
+						int fcid, int nfrags, int size )
+{
+	struct net80211_frag_cache *frag = &dev->frags[fcid];
+	int hdrsize = IEEE80211_TYP_FRAME_HEADER_LEN;
+	int nsize = size - hdrsize * ( nfrags - 1 );
+	int i;
+
+	struct io_buffer *niob = alloc_iob ( nsize );
+	struct ieee80211_frame *hdr;
+
+	/* Add the header from the first one... */
+	memcpy ( iob_put ( niob, hdrsize ), frag->iob[0]->data, hdrsize );
+
+	/* ... and all the data from all of them. */
+	for ( i = 0; i < nfrags; i++ ) {
+		int len = iob_len ( frag->iob[i] ) - hdrsize;
+		memcpy ( iob_put ( niob, len ),
+			 frag->iob[i]->data + hdrsize, len );
+	}
+
+	/* Turn off the fragment bit. */
+	hdr = niob->data;
+	hdr->fc &= ~IEEE80211_FC_MORE_FRAG;
+
+	return niob;
+}
+
+/**
+ * Handle receipt of 802.11 fragment
+ *
+ * @v dev	802.11 device
+ * @v iob	I/O buffer containing fragment
+ * @v signal	Signal strength with which fragment was received
+ */
+static void net80211_rx_frag ( struct net80211_device *dev,
+			       struct io_buffer *iob, int signal )
+{
+	struct ieee80211_frame *hdr = iob->data;
+	int fragnr = IEEE80211_FRAG ( hdr->seq );
+
+	if ( fragnr == 0 && ( hdr->fc & IEEE80211_FC_MORE_FRAG ) ) {
+		/* start a frag cache entry */
+		int i, newest = -1;
+		u32 curr_ticks = currticks(), newest_ticks = 0;
+		u32 timeout = ticks_per_sec() * NET80211_FRAG_TIMEOUT;
+
+		for ( i = 0; i < NET80211_NR_CONCURRENT_FRAGS; i++ ) {
+			if ( dev->frags[i].in_use == 0 )
+				break;
+
+			if ( dev->frags[i].start_ticks + timeout >=
+			     curr_ticks ) {
+				net80211_free_frags ( dev, i );
+				break;
+			}
+
+			if ( dev->frags[i].start_ticks > newest_ticks ) {
+				newest = i;
+				newest_ticks = dev->frags[i].start_ticks;
+			}
+		}
+
+		/* If we're being sent more concurrent fragmented
+		   packets than we can handle, drop the newest so the
+		   older ones have time to complete. */
+		if ( i == NET80211_NR_CONCURRENT_FRAGS ) {
+			i = newest;
+			net80211_free_frags ( dev, i );
+		}
+
+		dev->frags[i].in_use = 1;
+		dev->frags[i].seqnr = IEEE80211_SEQNR ( hdr->seq );
+		dev->frags[i].start_ticks = currticks();
+		dev->frags[i].iob[0] = iob;
+		return;
+	} else {
+		int i;
+		for ( i = 0; i < NET80211_NR_CONCURRENT_FRAGS; i++ ) {
+			if ( dev->frags[i].in_use && dev->frags[i].seqnr ==
+			     IEEE80211_SEQNR ( hdr->seq ) )
+				break;
+		}
+		if ( i == NET80211_NR_CONCURRENT_FRAGS ) {
+			/* Drop non-first not-in-cache fragments */
+			DBGC ( dev, "802.11 %p dropped fragment fc=%04x "
+			       "seq=%04x\n", dev, hdr->fc, hdr->seq );
+			free_iob ( iob );
+			return;
+		}
+
+		dev->frags[i].iob[fragnr] = iob;
+
+		if ( ! ( hdr->fc & IEEE80211_FC_MORE_FRAG ) ) {
+			int j, size = 0;
+			for ( j = 0; j < fragnr; j++ ) {
+				size += iob_len ( dev->frags[i].iob[j] );
+				if ( dev->frags[i].iob[j] == NULL )
+					break;
+			}
+			if ( j == fragnr ) {
+				/* We've got everything */
+				struct io_buffer *niob =
+				    net80211_accum_frags ( dev, i, fragnr,
+							   size );
+				net80211_free_frags ( dev, i );
+				net80211_rx ( dev, niob, signal, 0 );
+			} else {
+				DBGC ( dev, "802.11 %p dropping fragmented "
+				       "packet due to out-of-order arrival, "
+				       "fc=%04x seq=%04x\n", dev, hdr->fc,
+				       hdr->seq );
+				net80211_free_frags ( dev, i );
+			}
+		}
+	}
+}
+
+/**
+ * Handle receipt of 802.11 frame
+ *
+ * @v dev	802.11 device
+ * @v iob	I/O buffer
+ * @v signal	Received signal strength
+ * @v rate	Bitrate at which frame was received, in 100 kbps units
+ *
+ * If the rate or signal is unknown, 0 should be passed.
+ */
+void net80211_rx ( struct net80211_device *dev, struct io_buffer *iob,
+		   int signal, u16 rate )
+{
+	struct ieee80211_frame *hdr = iob->data;
+	u16 type = hdr->fc & IEEE80211_FC_TYPE;
+	if ( ( hdr->fc & IEEE80211_FC_VERSION ) != IEEE80211_THIS_VERSION )
+		goto drop;	/* drop invalid-version packets */
+
+	if ( type == IEEE80211_TYPE_CTRL )
+		goto drop;	/* we don't handle control packets,
+				   the hardware does */
+
+	if ( dev->last_rx_seq == hdr->seq )
+		goto drop;	/* avoid duplicate packet */
+	dev->last_rx_seq = hdr->seq;
+
+	if ( dev->hw->flags & NET80211_HW_RX_HAS_FCS ) {
+		/* discard the FCS */
+		iob_unput ( iob, 4 );
+	}
+
+	/* Only decrypt packets from our BSSID, to avoid spurious errors */
+	if ( ( hdr->fc & IEEE80211_FC_PROTECTED ) &&
+	     ! memcmp ( hdr->addr2, dev->bssid, ETH_ALEN ) ) {
+		/* Decrypt packet; record and drop if it fails */
+		struct io_buffer *niob;
+		struct net80211_crypto *crypto = dev->crypto;
+
+		if ( ! dev->crypto ) {
+			DBGC ( dev, "802.11 %p cannot decrypt packet "
+			       "without a cryptosystem\n", dev );
+			goto drop_crypt;
+		}
+
+		if ( ( hdr->addr1[0] & 1 ) && dev->gcrypto ) {
+			/* Use group decryption if needed */
+			crypto = dev->gcrypto;
+		}
+
+		niob = crypto->decrypt ( crypto, iob );
+		if ( ! niob ) {
+			DBGC ( dev, "802.11 %p decryption error\n", dev );
+			goto drop_crypt;
+		}
+		free_iob ( iob );
+		iob = niob;
+		hdr = iob->data;
+	}
+
+	dev->last_signal = signal;
+
+	/* Fragments go into the frag cache or get dropped. */
+	if ( IEEE80211_FRAG ( hdr->seq ) != 0
+	     || ( hdr->fc & IEEE80211_FC_MORE_FRAG ) ) {
+		net80211_rx_frag ( dev, iob, signal );
+		return;
+	}
+
+	/* Management frames get handled, enqueued, or dropped. */
+	if ( type == IEEE80211_TYPE_MGMT ) {
+		net80211_handle_mgmt ( dev, iob, signal );
+		return;
+	}
+
+	/* Data frames get dropped or sent to the net_device. */
+	if ( ( hdr->fc & IEEE80211_FC_SUBTYPE ) != IEEE80211_STYPE_DATA )
+		goto drop;	/* drop QoS, CFP, or null data packets */
+
+	/* Update rate-control algorithm */
+	if ( dev->rctl )
+		rc80211_update_rx ( dev, hdr->fc & IEEE80211_FC_RETRY, rate );
+
+	/* Pass packet onward */
+	if ( dev->state & NET80211_ASSOCIATED ) {
+		netdev_rx ( dev->netdev, iob );
+		return;
+	}
+
+	/* No association? Drop it. */
+	goto drop;
+
+ drop_crypt:
+	netdev_rx_err ( dev->netdev, NULL, EINVAL_CRYPTO_REQUEST );
+ drop:
+	DBGC2 ( dev, "802.11 %p dropped packet fc=%04x seq=%04x\n", dev,
+		hdr->fc, hdr->seq );
+	free_iob ( iob );
+	return;
+}
+
+/** Indicate an error in receiving a packet
+ *
+ * @v dev	802.11 device
+ * @v iob	I/O buffer with received packet, or NULL
+ * @v rc	Error code
+ *
+ * This logs the error with the wrapping net_device, and frees iob if
+ * it is passed.
+ */
+void net80211_rx_err ( struct net80211_device *dev,
+		       struct io_buffer *iob, int rc )
+{
+	netdev_rx_err ( dev->netdev, iob, rc );
+}
+
+/** Indicate the completed transmission of a packet
+ *
+ * @v dev	802.11 device
+ * @v iob	I/O buffer of transmitted packet
+ * @v retries	Number of times this packet was retransmitted
+ * @v rc	Error code, or 0 for success
+ *
+ * This logs an error with the wrapping net_device if one occurred,
+ * and removes and frees the I/O buffer from its TX queue. The
+ * provided retry information is used to tune our transmission rate.
+ *
+ * If the packet did not need to be retransmitted because it was
+ * properly ACKed the first time, @a retries should be 0.
+ */
+void net80211_tx_complete ( struct net80211_device *dev,
+			    struct io_buffer *iob, int retries, int rc )
+{
+	/* Update rate-control algorithm */
+	if ( dev->rctl )
+		rc80211_update_tx ( dev, retries, rc );
+
+	/* Pass completion onward */
+	netdev_tx_complete_err ( dev->netdev, iob, rc );
+}
+
+/** Common 802.11 errors */
+struct errortab common_wireless_errors[] __errortab = {
+	__einfo_errortab ( EINFO_EINVAL_CRYPTO_REQUEST ),
+	__einfo_errortab ( EINFO_ECONNRESET_UNSPECIFIED ),
+	__einfo_errortab ( EINFO_ECONNRESET_INACTIVITY ),
+	__einfo_errortab ( EINFO_ECONNRESET_4WAY_TIMEOUT ),
+	__einfo_errortab ( EINFO_ECONNRESET_8021X_FAILURE ),
+	__einfo_errortab ( EINFO_ECONNREFUSED_FAILURE ),
+	__einfo_errortab ( EINFO_ECONNREFUSED_ASSOC_DENIED ),
+	__einfo_errortab ( EINFO_ECONNREFUSED_AUTH_ALGO_UNSUPP ),
+};