ieee80211_wireless.c

Linux下wifi实现

/*-
 * Copyright (c) 2002-2005 Sam Leffler, Errno Consulting
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer,
 *    without modification.
 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
 *    similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any
 *    redistribution must be conditioned upon including a substantially
 *    similar Disclaimer requirement for further binary redistribution.
 * 3. Neither the names of the above-listed copyright holders nor the names
 *    of any contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * NO WARRANTY
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
 * THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY,
 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
 * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGES.
 *
 * $Id: ieee80211_wireless.c 1676 2006-07-06 03:23:08Z brian $
 */

/*
 * Wireless extensions support for 802.11 common code.
 */
#include <linux/config.h>

#ifdef CONFIG_NET_WIRELESS
#include <linux/version.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/utsname.h>
#include <linux/if_arp.h>		/* XXX for ARPHRD_ETHER */
#include <linux/delay.h>
#include <net/iw_handler.h>

#if WIRELESS_EXT < 14
#error "Wireless extensions v14 or better is needed."
#endif

#include <asm/uaccess.h>

#include "if_media.h"

#include <net80211/ieee80211_var.h>
#include <net80211/ieee80211_linux.h>

#define	IS_UP(_dev) \
	(((_dev)->flags & (IFF_RUNNING|IFF_UP)) == (IFF_RUNNING|IFF_UP))
#define	IS_UP_AUTO(_vap) \
	(IS_UP((_vap)->iv_dev) && \
	 (_vap)->iv_ic->ic_roaming == IEEE80211_ROAMING_AUTO)
#define	RESCAN	1

/*
 * Compatibility definition of statistics flags
 * (bitmask in (struct iw_quality *)->updated)
 */
#ifndef IW_QUAL_QUAL_UPDATED
#define IW_QUAL_QUAL_UPDATED	0x01	/* Value was updated since last read */
#define IW_QUAL_LEVEL_UPDATED	0x02
#define IW_QUAL_NOISE_UPDATED	0x04
#define IW_QUAL_QUAL_INVALID	0x10	/* Driver doesn't provide value */
#define IW_QUAL_LEVEL_INVALID	0x20
#define IW_QUAL_NOISE_INVALID	0x40
#endif /* IW_QUAL_QUAL_UPDATED */

#ifndef IW_QUAL_ALL_UPDATED
#define IW_QUAL_ALL_UPDATED \
	(IW_QUAL_QUAL_UPDATED | IW_QUAL_LEVEL_UPDATED | IW_QUAL_NOISE_UPDATED)
#endif
#ifndef IW_QUAL_ALL_INVALID
#define IW_QUAL_ALL_INVALID \
	(IW_QUAL_QUAL_INVALID | IW_QUAL_LEVEL_INVALID | IW_QUAL_NOISE_INVALID)
#endif

/*
 * Units are in db above the noise floor. That means the
 * rssi values reported in the tx/rx descriptors in the
 * driver are the SNR expressed in db.
 *
 * If you assume that the noise floor is -95, which is an
 * excellent assumption 99.5 % of the time, then you can
 * derive the absolute signal level (i.e. -95 + rssi). 
 * There are some other slight factors to take into account
 * depending on whether the rssi measurement is from 11b,
 * 11g, or 11a.   These differences are at most 2db and
 * can be documented.
 *
 * NB: various calculations are based on the orinoco/wavelan
 *     drivers for compatibility
 */
static void
set_quality(struct iw_quality *iq, u_int rssi)
{
	iq->qual = rssi;
	/* NB: max is 94 because noise is hardcoded to 161 */
	if (iq->qual > 94)
		iq->qual = 94;

	iq->noise = 161;		/* -95dBm */
	iq->level = iq->noise + iq->qual;
	iq->updated = IW_QUAL_ALL_UPDATED;
}

static void
preempt_scan(struct net_device *dev, int max_grace, int max_wait)
{
	struct ieee80211vap *vap = dev->priv;
	struct ieee80211com *ic = vap->iv_ic;
	int total_delay = 0;
	int cancelled = 0, ready = 0;
	while (!ready && total_delay < max_grace + max_wait) {
	  if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) {
	    ready = 1;
	  } else {
	    if (!cancelled && total_delay > max_grace) {
	      /* 
		 Cancel any existing active scan, so that any new parameters
		 in this scan ioctl (or the defaults) can be honored, then
		 wait around a while to see if the scan cancels properly.
	      */
	      IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
				"%s: cancel pending scan request\n", __func__);
	      (void) ieee80211_cancel_scan(vap);
	      cancelled = 1;
	    }
	    mdelay (1);
	    total_delay += 1;
	  }
	}
	if (!ready) {
	  IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, 
			    "%s: Timeout cancelling current scan.\n", 
			    __func__); 
	}
}
	
static struct iw_statistics *
ieee80211_iw_getstats(struct net_device *dev)
{
	struct ieee80211vap *vap = dev->priv;
	struct iw_statistics *is = &vap->iv_iwstats;

	set_quality(&is->qual, ieee80211_getrssi(vap->iv_ic));
	is->status = vap->iv_state;
	is->discard.nwid = vap->iv_stats.is_rx_wrongbss +
		vap->iv_stats.is_rx_ssidmismatch;
	is->discard.code = vap->iv_stats.is_rx_wepfail +
		vap->iv_stats.is_rx_decryptcrc;
	is->discard.fragment = 0;
	is->discard.retries = 0;
	is->discard.misc = 0;

	is->miss.beacon = 0;

	return is;
}

static int
ieee80211_ioctl_giwname(struct net_device *dev, struct iw_request_info *info,
	char *name, char *extra)
{
	struct ieee80211vap *vap = dev->priv;
	struct ieee80211_channel *c = vap->iv_ic->ic_curchan;

	if (IEEE80211_IS_CHAN_108G(c))
		strncpy(name, "IEEE 802.11Tg", IFNAMSIZ);
	else if (IEEE80211_IS_CHAN_108A(c))
		strncpy(name, "IEEE 802.11Ta", IFNAMSIZ);
	else if (IEEE80211_IS_CHAN_TURBO(c))
		strncpy(name, "IEEE 802.11T", IFNAMSIZ);
	else if (IEEE80211_IS_CHAN_ANYG(c))
		strncpy(name, "IEEE 802.11g", IFNAMSIZ);
	else if (IEEE80211_IS_CHAN_A(c))
		strncpy(name, "IEEE 802.11a", IFNAMSIZ);
	else if (IEEE80211_IS_CHAN_B(c))
		strncpy(name, "IEEE 802.11b", IFNAMSIZ);
	else
		strncpy(name, "IEEE 802.11", IFNAMSIZ);
	/* XXX FHSS */
	return 0;
}

/*
 * Get a key index from a request.  If nothing is
 * specified in the request we use the current xmit
 * key index.  Otherwise we just convert the index
 * to be base zero.
 */
static int
getiwkeyix(struct ieee80211vap *vap, const struct iw_point* erq, int *kix)
{
	int kid;

	kid = erq->flags & IW_ENCODE_INDEX;
	if (kid < 1 || kid > IEEE80211_WEP_NKID) {
		kid = vap->iv_def_txkey;
		if (kid == IEEE80211_KEYIX_NONE)
			kid = 0;
	} else
		--kid;
	if (0 <= kid && kid < IEEE80211_WEP_NKID) {
		*kix = kid;
		return 0;
	} else
		return -EINVAL;
}

static int
ieee80211_ioctl_siwencode(struct net_device *dev,
	struct iw_request_info *info, struct iw_point *erq, char *keybuf)
{
	struct ieee80211vap *vap = dev->priv;
	int kid, error;
	int wepchange = 0;

	if ((erq->flags & IW_ENCODE_DISABLED) == 0) {
		/*
		 * Enable crypto, set key contents, and
		 * set the default transmit key.
		 */
		error = getiwkeyix(vap, erq, &kid);
		if (error < 0)
			return error;
		if (erq->length > IEEE80211_KEYBUF_SIZE)
			return -EINVAL;
		/* XXX no way to install 0-length key */
		ieee80211_key_update_begin(vap);
		if (erq->length > 0) {
			struct ieee80211_key *k = &vap->iv_nw_keys[kid];

			/*
			 * Set key contents.  This interface only supports WEP.
			 * Indicate intended key index.			 
			 */
			k->wk_keyix = kid;
			if (ieee80211_crypto_newkey(vap, IEEE80211_CIPHER_WEP,
			    IEEE80211_KEY_XMIT | IEEE80211_KEY_RECV, k)) {
				k->wk_keylen = erq->length;
				memcpy(k->wk_key, keybuf, erq->length);
				memset(k->wk_key + erq->length, 0,
					IEEE80211_KEYBUF_SIZE - erq->length);
				if (!ieee80211_crypto_setkey(vap, k, vap->iv_myaddr, NULL))
					error = -EINVAL;		/* XXX */
			} else
				error = -EINVAL;
		} else {
			/*
			 * When the length is zero the request only changes
			 * the default transmit key.  Verify the new key has
			 * a non-zero length.
			 */
			if (vap->iv_nw_keys[kid].wk_keylen == 0)
				error = -EINVAL;
		}
		if (error == 0) {
			/*
			 * The default transmit key is only changed when:
			 * 1. Privacy is enabled and no key matter is
			 *    specified.
			 * 2. Privacy is currently disabled.
			 * This is deduced from the iwconfig man page.
			 */
			if (erq->length == 0 ||
			    (vap->iv_flags & IEEE80211_F_PRIVACY) == 0)
				vap->iv_def_txkey = kid;
			wepchange = (vap->iv_flags & IEEE80211_F_PRIVACY) == 0;
			vap->iv_flags |= IEEE80211_F_PRIVACY;
		}
		ieee80211_key_update_end(vap);
	} else {
		if ((vap->iv_flags & IEEE80211_F_PRIVACY) == 0)
			return 0;
		vap->iv_flags &= ~IEEE80211_F_PRIVACY;
		wepchange = 1;
		error = 0;
	}
	if (error == 0) {
		/* Set policy for unencrypted frames */	
		if ((erq->flags & IW_ENCODE_OPEN) && 
		    (!(erq->flags & IW_ENCODE_RESTRICTED))) {
			vap->iv_flags &= ~IEEE80211_F_DROPUNENC;
		} else if (!(erq->flags & IW_ENCODE_OPEN) && 
			 (erq->flags & IW_ENCODE_RESTRICTED)) {
			vap->iv_flags |= IEEE80211_F_DROPUNENC;
		} else {
			/* Default policy */
			if (vap->iv_flags & IEEE80211_F_PRIVACY) 
				vap->iv_flags |= IEEE80211_F_DROPUNENC;
			else
				vap->iv_flags &= ~IEEE80211_F_DROPUNENC;
		}	
	}
	if (error == 0 && IS_UP(vap->iv_dev)) {
		/*
		 * Device is up and running; we must kick it to
		 * effect the change.  If we're enabling/disabling
		 * crypto use then we must re-initialize the device
		 * so the 802.11 state machine is reset.  Otherwise
		 * the key state should have been updated above.
		 */
		if (wepchange && IS_UP_AUTO(vap))
			ieee80211_new_state(vap, IEEE80211_S_SCAN, 0);
	}
#ifdef ATH_SUPERG_XR
	/* set the same params on the xr vap device if exists */
	if (!error && vap->iv_xrvap && !(vap->iv_flags & IEEE80211_F_XR))
		ieee80211_ioctl_siwencode(vap->iv_xrvap->iv_dev, info, erq, keybuf);
#endif
	return error;
}

static int
ieee80211_ioctl_giwencode(struct net_device *dev, struct iw_request_info *info,
	struct iw_point *erq, char *key)
{
	struct ieee80211vap *vap = dev->priv;
	struct ieee80211_key *k;
	int error, kid;

	if (vap->iv_flags & IEEE80211_F_PRIVACY) {
		error = getiwkeyix(vap, erq, &kid);
		if (error < 0)
			return error;
		k = &vap->iv_nw_keys[kid];
		/* XXX no way to return cipher/key type */

		erq->flags = kid + 1;			/* NB: base 1 */
		if (erq->length > k->wk_keylen)
			erq->length = k->wk_keylen;
		memcpy(key, k->wk_key, erq->length);
		erq->flags |= IW_ENCODE_ENABLED;
	} else {
		erq->length = 0;
		erq->flags = IW_ENCODE_DISABLED;
	}
	if (vap->iv_flags & IEEE80211_F_DROPUNENC)
		erq->flags |= IW_ENCODE_RESTRICTED;
	else
		erq->flags |= IW_ENCODE_OPEN;
	return 0;
}

#ifndef ifr_media
#define	ifr_media	ifr_ifru.ifru_ivalue
#endif

static int
ieee80211_ioctl_siwrate(struct net_device *dev, struct iw_request_info *info,
	struct iw_param *rrq, char *extra)
{
	static const u_int mopts[] = {
		IFM_AUTO,
		IFM_IEEE80211_11A,
		IFM_IEEE80211_11B,
		IFM_IEEE80211_11G,
		IFM_IEEE80211_FH,
		IFM_IEEE80211_11A | IFM_IEEE80211_TURBO,
		IFM_IEEE80211_11G | IFM_IEEE80211_TURBO,
	};
	struct ieee80211vap *vap = dev->priv;
	struct ieee80211com *ic = vap->iv_ic;
	struct ifreq ifr;
	int rate, retv;

	if (vap->iv_media.ifm_cur == NULL)
		return -EINVAL;
	memset(&ifr, 0, sizeof(ifr));
	ifr.ifr_media = vap->iv_media.ifm_cur->ifm_media &~ (IFM_MMASK|IFM_TMASK);
	ifr.ifr_media |= mopts[vap->iv_des_mode];
	if (rrq->fixed) {
		/* XXX fudge checking rates */
		rate = ieee80211_rate2media(ic, 2 * rrq->value / 1000000,
			vap->iv_des_mode);
		if (rate == IFM_AUTO)		/* NB: unknown rate */
			return -EINVAL;
	} else
		rate = IFM_AUTO;
	ifr.ifr_media |= IFM_SUBTYPE(rate);

	/* refresh media capabilities based on channel */
	ifmedia_removeall(&vap->iv_media);
	(void) ieee80211_media_setup(ic, &vap->iv_media,
		vap->iv_caps, vap->iv_media.ifm_change, vap->iv_media.ifm_status);

	retv = ifmedia_ioctl(vap->iv_dev, &ifr, &vap->iv_media, SIOCSIFMEDIA);
	if (retv == -ENETRESET)
		retv = IS_UP_AUTO(vap) ? ieee80211_open(vap->iv_dev) : 0;
	return retv;
}

static int
ieee80211_ioctl_giwrate(struct net_device *dev,	struct iw_request_info *info,
	struct iw_param *rrq, char *extra)
{
	struct ieee80211vap *vap = dev->priv;
	struct ifmediareq imr;
	int rate;

	memset(&imr, 0, sizeof(imr));
	vap->iv_media.ifm_status(vap->iv_dev, &imr);

	rrq->fixed = IFM_SUBTYPE(vap->iv_media.ifm_media) != IFM_AUTO;
	/* media status will have the current xmit rate if available */
	rate = ieee80211_media2rate(imr.ifm_active);
	if (rate == -1)		/* IFM_AUTO */
		rate = 0;
	rrq->value = 1000000 * (rate / 2);

	return 0;
}

static int
ieee80211_ioctl_siwsens(struct net_device *dev,	struct iw_request_info *info,
	struct iw_param *sens, char *extra)
{
	return 0;
}

static int
ieee80211_ioctl_giwsens(struct net_device *dev,	struct iw_request_info *info,
	struct iw_param *sens, char *extra)
{
	sens->value = 0;
	sens->fixed = 1;

	return 0;
}

static int
ieee80211_ioctl_siwrts(struct net_device *dev, struct iw_request_info *info,
	struct iw_param *rts, char *extra)
{
	struct ieee80211vap *vap = dev->priv;
	struct ieee80211com *ic = vap->iv_ic;
	u16 val;

	if (rts->disabled)
		val = IEEE80211_RTS_MAX;
	else if (IEEE80211_RTS_MIN <= rts->value &&
	    rts->value <= IEEE80211_RTS_MAX)
		val = rts->value;
	else
		return -EINVAL;
	if (val != vap->iv_rtsthreshold) {
		vap->iv_rtsthreshold = val;
		if (IS_UP(vap->iv_dev))
			return ic->ic_reset(ic->ic_dev);
	}