ieee80211_scan_ap.c.svn-base

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/*-
 * Copyright (c) 2002-2005 Sam Leffler, Errno Consulting
 * Copyright (c) 2005  Matt Mackall <[e-mail]>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * $Id$
 */
#ifndef EXPORT_SYMTAB
#define	EXPORT_SYMTAB
#endif

/*
 * IEEE 802.11 ap scanning support.
 */
#ifndef AUTOCONF_INCLUDED
#include <linux/config.h>
#endif
#include <linux/version.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/init.h>
#include <linux/delay.h>

#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,11)
/* Copied from Linux lib/sort.c */
static void u32_swap(void *a, void *b, int size)
{
	u32 t = *(u32 *)a;
	*(u32 *)a = *(u32 *)b;
	*(u32 *)b = t;
}

static void generic_swap(void *a, void *b, int size)
{
	char t;

	do {
		t = *(char *)a;
		*(char *)a++ = *(char *)b;
		*(char *)b++ = t;
	} while (--size > 0);
}

/**
 * sort - sort an array of elements
 * @base: pointer to data to sort
 * @num: number of elements
 * @size: size of each element
 * @cmp: pointer to comparison function
 * @swap: pointer to swap function or NULL
 *
 * This function does a heapsort on the given array. You may provide a
 * swap function optimized to your element type.
 *
 * Sorting time is O(n log n) both on average and worst-case. While
 * qsort is about 20% faster on average, it suffers from exploitable
 * O(n*n) worst-case behavior and extra memory requirements that make
 * it less suitable for kernel use.
 */

void sort(void *base, size_t num, size_t size,
	  int (*cmp)(const void *, const void *),
	  void (*swap)(void *, void *, int size))
{
	/* pre-scale counters for performance */
	int i = (num/2 - 1) * size, n = num * size, c, r;

	if (!swap)
		swap = (size == 4 ? u32_swap : generic_swap);

	/* heapify */
	for ( ; i >= 0; i -= size) {
		for (r = i; r * 2 + size < n; r  = c) {
			c = r * 2 + size;
			if (c < n - size && cmp(base + c, base + c + size) < 0)
				c += size;
			if (cmp(base + r, base + c) >= 0)
				break;
			swap(base + r, base + c, size);
		}
	}

	/* sort */
	for (i = n - size; i > 0; i -= size) {
		swap(base, base + i, size);
		for (r = 0; r * 2 + size < i; r = c) {
			c = r * 2 + size;
			if (c < i - size && cmp(base + c, base + c + size) < 0)
				c += size;
			if (cmp(base + r, base + c) >= 0)
				break;
			swap(base + r, base + c, size);
		}
	}
}
#else
#include <linux/sort.h>
#endif

#include "if_media.h"

#include <net80211/ieee80211_var.h>

#define	AP_PURGE_SCANS	2			/* age for purging entries (scans) */
#define RSSI_LPF_LEN	10
#define	RSSI_EP_MULTIPLIER	(1 << 7)	/* pow2 to optimize out * and / */
#define RSSI_IN(x)		((x) * RSSI_EP_MULTIPLIER)
#define LPF_RSSI(x, y, len)	(((x) * ((len) - 1) + (y)) / (len))
#define RSSI_LPF(x, y) do {						\
	if ((y) >= -20)							\
		x = LPF_RSSI((x), RSSI_IN((y)), RSSI_LPF_LEN);		\
} while (0)
#define	EP_RND(x, mul) \
	((((x)%(mul)) >= ((mul)/2)) ? howmany(x, mul) : (x)/(mul))
#define	RSSI_GET(x)	EP_RND(x, RSSI_EP_MULTIPLIER)
#define	AP_HASHSIZE	32
/* simple hash is enough for variation of macaddr */
#define	AP_HASH(addr)	\
	(((const u_int8_t *)(addr))[IEEE80211_ADDR_LEN - 1] % AP_HASHSIZE)
#define	SCAN_AP_LOCK_INIT(_st, _name)					\
	spin_lock_init(&(_st)->as_lock)
#define	SCAN_AP_LOCK_DESTROY(_st)
#define	SCAN_AP_LOCK_IRQ(_st) do {					\
	unsigned long __stlockflags;					\
	spin_lock_irqsave(&(_st)->as_lock, __stlockflags);
#define	SCAN_AP_UNLOCK_IRQ(_st)						\
	spin_unlock_irqrestore(&(_st)->as_lock, __stlockflags);		\
} while (0)
#define	SCAN_AP_UNLOCK_IRQ_EARLY(_st)					\
	spin_unlock_irqrestore(&(_st)->as_lock, __stlockflags);

#define	SCAN_AP_GEN_LOCK_INIT(_st, _name)				\
	spin_lock_init(&(_st)->as_scanlock)
#define	SCAN_AP_GEN_LOCK_DESTROY(_st)
#define	SCAN_AP_GEN_LOCK(_st)		spin_lock(&(_st)->as_scanlock);
#define	SCAN_AP_GEN_UNLOCK(_st)	spin_unlock(&(_st)->as_scanlock);

struct scan_entry {
	struct ieee80211_scan_entry base;
	TAILQ_ENTRY(scan_entry) se_list;
	LIST_ENTRY(scan_entry) se_hash;
	u_int8_t	se_seen;	/* seen during current scan */
	u_int8_t	se_notseen;	/* not seen in previous scans */
	u_int32_t se_avgrssi;		/* LPF rssi state */
	unsigned long se_lastupdate;	/* time of last update */
	unsigned long se_lastfail;	/* time of last failure */
	unsigned long se_lastassoc;	/* time of last association */
	u_int se_scangen;		/* iterator scan gen# */
};

struct ap_state {
	unsigned int as_vap_desired_mode;       /* Used for channel selection, 
						 * vap->iv_des_mode */
	unsigned int as_required_mode;          /* Used for channel selection, 
						 * filtered version of 
						 * as_vap_desired_mode */
	int as_maxrssi[IEEE80211_CHAN_MAX]; 	/* Used for channel selection */

	/* These fields are just for scan caching for returning responses to
	 * wireless extensions.  i.e. show peers, APs, etc. */
	spinlock_t as_lock;			/* on scan table */
	int as_newscan;				/* trigger for updating 
						 * seen/not-seen for aging */
	TAILQ_HEAD(, scan_entry) as_entry;	/* all entries */
	ATH_LIST_HEAD(, scan_entry) as_hash[AP_HASHSIZE];
	spinlock_t as_scanlock;			/* on as_scangen */
	u_int as_scangen;			/* gen# for iterator */

	struct IEEE80211_TQ_STRUCT as_actiontq;	/* tasklet for "action" */
	struct ieee80211_scan_entry as_selbss;	/* selected bss for action tasklet */
	int (*as_action)(struct ieee80211vap *, const struct ieee80211_scan_entry *);
};

static int ap_flush(struct ieee80211_scan_state *);
static void action_tasklet(IEEE80211_TQUEUE_ARG);
static struct ieee80211_channel *find11gchannel(struct ieee80211com *ic, 
		int i, int freq);

static const u_int chanflags[] = {
	IEEE80211_CHAN_B,	/* IEEE80211_MODE_AUTO */
	IEEE80211_CHAN_A,	/* IEEE80211_MODE_11A */
	IEEE80211_CHAN_B,	/* IEEE80211_MODE_11B */
	IEEE80211_CHAN_PUREG,	/* IEEE80211_MODE_11G */
	IEEE80211_CHAN_FHSS,	/* IEEE80211_MODE_FH */
	IEEE80211_CHAN_A,	/* IEEE80211_MODE_TURBO_A */ /* for turbo mode 
							      * look for AP in 
							      * normal channel 
							      */
	IEEE80211_CHAN_PUREG,	/* IEEE80211_MODE_TURBO_G */
	IEEE80211_CHAN_ST,	/* IEEE80211_MODE_TURBO_STATIC_A */
};

static const u_int16_t rcl1[] =		/* 8 FCC channel: 52, 56, 60, 64, 
					 *                36, 40, 44, 48 */
{ 5260, 5280, 5300, 5320, 5180, 5200, 5220, 5240 };
static const u_int16_t rcl2[] =		/* 4 MKK channels: 34, 38, 42, 46 */
{ 5170, 5190, 5210, 5230 };
static const u_int16_t rcl3[] =		/* 2.4Ghz ch: 1,6,11,7,13 */
{ 2412, 2437, 2462, 2442, 2472 };
static const u_int16_t rcl4[] =		/* 5 FCC channel: 149, 153, 161, 165 */
{ 5745, 5765, 5785, 5805, 5825 };
static const u_int16_t rcl7[] =		/* 11 ETSI channel: 100, 104, 108, 112,
					 *                  116, 120, 124, 128, 
					 *                  132, 136, 140 */
{ 5500, 5520, 5540, 5560, 5580, 5600, 5620, 5640, 5660, 5680, 5700 };
static const u_int16_t rcl8[] =		/* 2.4Ghz ch: 2,3,4,5,8,9,10,12 */
{ 2417, 2422, 2427, 2432, 2447, 2452, 2457, 2467 };
static const u_int16_t rcl9[] =		/* 2.4Ghz ch: 14 */
{ 2484 };
static const u_int16_t rcl10[] =	/* Added Korean channels 2312-2372 */
{ 2312, 2317, 2322, 2327, 2332, 2337, 2342, 2347, 2352, 2357, 2362, 2367, 2372 };
static const u_int16_t rcl11[] =	/* Added Japan channels in 4.9/5.0 spectrum */
{ 5040, 5060, 5080, 4920, 4940, 4960, 4980 };
#ifdef ATH_TURBO_SCAN
static const u_int16_t rcl5[] =		/* 3 static turbo channels */
{ 5210, 5250, 5290 };
static const u_int16_t rcl6[] =		/* 2 static turbo channels */
{ 5760, 5800 };
static const u_int16_t rcl6x[] =		/* 4 FCC3 turbo channels */
{ 5540, 5580, 5620, 5660 };
static const u_int16_t rcl12[] =		/* 2.4Ghz Turbo channel 6 */
{ 2437 };
static const u_int16_t rcl13[] =		/* dynamic Turbo channels */
{ 5200, 5240, 5280, 5765, 5805 };
#endif /* ATH_TURBO_SCAN */

struct scanlist {
	u_int16_t	mode;
	u_int16_t	count;
	const u_int16_t	*list;
};

#define	IEEE80211_MODE_TURBO_STATIC_A	IEEE80211_MODE_MAX
#define	X(a)	.count = ARRAY_SIZE(a), .list = a

static const struct scanlist staScanTable[] = {
	{ IEEE80211_MODE_11B,   		X(rcl3)  },
	{ IEEE80211_MODE_11A,   		X(rcl1)  },
	{ IEEE80211_MODE_11A,   		X(rcl2)  },
	{ IEEE80211_MODE_11B,   		X(rcl8)  },
	{ IEEE80211_MODE_11B,   		X(rcl9)  },
	{ IEEE80211_MODE_11A,   		X(rcl4)  },
#ifdef ATH_TURBO_SCAN
	{ IEEE80211_MODE_TURBO_STATIC_A,	X(rcl5)  },
	{ IEEE80211_MODE_TURBO_STATIC_A,	X(rcl6)  },
	{ IEEE80211_MODE_TURBO_A,		X(rcl6x) },
	{ IEEE80211_MODE_TURBO_A,		X(rcl13) },
#endif /* ATH_TURBO_SCAN */
	{ IEEE80211_MODE_11A,			X(rcl7)  },
	{ IEEE80211_MODE_11B,			X(rcl10) },
	{ IEEE80211_MODE_11A,			X(rcl11) },
#ifdef ATH_TURBO_SCAN
	{ IEEE80211_MODE_TURBO_G,		X(rcl12) },
#endif /* ATH_TURBO_SCAN */
	{ .list = NULL }
};

#undef X
/* This function must be invoked with locks acquired */
static void
add_channels(struct ieee80211com *ic,
	struct ieee80211_scan_state *ss,
	enum ieee80211_phymode mode, const u_int16_t freq[], int nfreq)
{
	struct ieee80211_channel *c, *cg;
	u_int modeflags;
	int i;

	KASSERT(mode < ARRAY_SIZE(chanflags), ("Unexpected mode %u", mode));
	modeflags = chanflags[mode];
	for (i = 0; i < nfreq; i++) {
		c = ieee80211_find_channel(ic, freq[i], modeflags);
		if ((c == NULL) || isclr(ic->ic_chan_active, c->ic_ieee))
			continue;
		if (mode == IEEE80211_MODE_AUTO) {
			/* XXX special-case 11b/g channels so we select
			 *     the g channel if both are present. */
			if (IEEE80211_IS_CHAN_B(c) &&
			    (cg = find11gchannel(ic, i, c->ic_freq)) != NULL)
				c = cg;
		}
		if (ss->ss_last >= IEEE80211_SCAN_MAX)
			break;
		ss->ss_chans[ss->ss_last++] = c;
	}
}

/* This function must be invoked with locks acquired */
static int
checktable(const struct scanlist *scan, const struct ieee80211_channel *c)
{
	int i;

	for (; scan->list != NULL; scan++) {
		for (i = 0; i < scan->count; i++)
			if (scan->list[i] == c->ic_freq)
				return 1;
	}
	return 0;
}

/*
 * Attach prior to any scanning work.
 */
static int
ap_attach(struct ieee80211_scan_state *ss)
{
	struct ap_state *as;

	_MOD_INC_USE(THIS_MODULE, return 0);

	MALLOC(as, struct ap_state *, sizeof(struct ap_state),
		M_80211_SCAN, M_NOWAIT | M_ZERO);
	if (as == NULL)
		return 0;
	SCAN_AP_LOCK_INIT(as, "scan_ap");
	SCAN_AP_GEN_LOCK_INIT(as, "scan_ap_gen");
	TAILQ_INIT(&as->as_entry);
	IEEE80211_INIT_TQUEUE(&as->as_actiontq, action_tasklet, ss);
	ss->ss_priv = as;
	ap_flush(ss);
	return 1;
}

/*
 * Cleanup any private state.
 */
static int
ap_detach(struct ieee80211_scan_state *ss)
{
	struct ap_state *as = ss->ss_priv;

	if (as != NULL) {
		ap_flush(ss);
		IEEE80211_CANCEL_TQUEUE(&as->as_actiontq);
		FREE(as, M_80211_SCAN);
	}

	_MOD_DEC_USE(THIS_MODULE);
	return 1;
}