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madwifi/net80211/ieee80211_scan_ap.c

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/*-
* Copyright (c) 2002-2005 Sam Leffler, Errno Consulting
* Copyright (c) 2005 Matt Mackall <mpm@selenic.com>
* 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.
*/
#if !defined(AUTOCONF_INCLUDED) && !defined(CONFIG_LOCALVERSION)
#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>
#include <linux/sort.h>
#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;
}
/*
* Flush all per-scan state.
*/
static int
ap_flush(struct ieee80211_scan_state *ss)
{
struct ap_state *as = ss->ss_priv;
struct scan_entry *se, *next;
SCAN_AP_LOCK_IRQ(as);
memset(as->as_maxrssi, 0, sizeof(as->as_maxrssi));
TAILQ_FOREACH_SAFE(se, &as->as_entry, se_list, next) {
TAILQ_REMOVE(&as->as_entry, se, se_list);
LIST_REMOVE(se, se_hash);
FREE(se, M_80211_SCAN);
}
ss->ss_last = 0; /* ensure no channel will be picked */
SCAN_AP_UNLOCK_IRQ(as);
return 0;
}
/* This function must be invoked with locks acquired */
static void
saveie(u_int8_t **iep, const u_int8_t *ie)
{
if (ie == NULL)
*iep = NULL;
else
ieee80211_saveie(iep, ie);
}
/* This function must be invoked with locks acquired */
static struct ieee80211_channel *
find11gchannel(struct ieee80211com *ic, int i, int freq)
{
struct ieee80211_channel *c;
int j;
/* The normal ordering in the channel list is b channel
* immediately followed by g so optimize the search for
* this. We'll still do a full search just in case. */
for (j = i + 1; j < ic->ic_nchans; j++) {
c = &ic->ic_channels[j];
if ((c->ic_freq == freq) && IEEE80211_IS_CHAN_ANYG(c))
return c;
}
for (j = 0; j < i; j++) {
c = &ic->ic_channels[j];
if ((c->ic_freq == freq) && IEEE80211_IS_CHAN_ANYG(c))
return c;
}
return NULL;
}
/*
* Start an ap scan by populating the channel list.
*/
static int
ap_start(struct ieee80211_scan_state *ss, struct ieee80211vap *vap)
{
struct ap_state *as = ss->ss_priv;
struct ieee80211com *ic = NULL;
const struct scanlist *sl = NULL;
struct ieee80211_channel *c = NULL;
int i;
unsigned int mode = 0;
SCAN_AP_LOCK_IRQ(as);
ic = vap->iv_ic;
/* Determine mode flags to match, or leave zero for auto mode */
as->as_vap_desired_mode = vap->iv_des_mode;
as->as_required_mode = 0;
if (as->as_vap_desired_mode != IEEE80211_MODE_AUTO) {
as->as_required_mode = chanflags[as->as_vap_desired_mode];
if ((vap->iv_ath_cap & IEEE80211_ATHC_TURBOP) &&
(as->as_required_mode != IEEE80211_CHAN_ST)) {
/* Fixup for dynamic turbo flags */
if (as->as_vap_desired_mode == IEEE80211_MODE_11G)
as->as_required_mode = IEEE80211_CHAN_108G;
else
as->as_required_mode = IEEE80211_CHAN_108A;
}
}
ss->ss_last = 0;
/* Use the table of ordered channels to construct the list
* of channels for scanning. Any channels in the ordered
* list not in the master list will be discarded. */
for (sl = staScanTable; sl->list != NULL; sl++) {
mode = sl->mode;
/* The scan table marks 2.4Ghz channels as b
* so if the desired mode is 11g, then use
* the 11b channel list but upgrade the mode. */
if (as->as_vap_desired_mode &&
(as->as_vap_desired_mode != mode) &&
(as->as_vap_desired_mode == IEEE80211_MODE_11G) &&
(mode == IEEE80211_MODE_11B))
mode = IEEE80211_MODE_11G;
/* If we are in "AUTO" mode, upgrade the mode to auto.
* This lets add_channels upgrade an 11b channel to
* 11g if available. */
if (!as->as_vap_desired_mode && (mode == IEEE80211_MODE_11B))
mode = IEEE80211_MODE_AUTO;
/* Add the list of the channels; any that are not
* in the master channel list will be discarded. */
add_channels(ic, ss, mode, sl->list, sl->count);
}
/* Add the channels from the ic (from HAL) that are not present
* in the staScanTable, assuming they pass the sanity checks... */
for (i = 0; i < ic->ic_nchans; i++) {
c = &ic->ic_channels[i];
/* XR is not supported on turbo channels */
if (IEEE80211_IS_CHAN_TURBO(c) && vap->iv_flags & IEEE80211_F_XR)
continue;
/* Dynamic channels are scanned in base mode */
if (!as->as_required_mode && !IEEE80211_IS_CHAN_ST(c))
continue;
/* Use any 11g channel instead of 11b one. */
if (vap->iv_des_mode == IEEE80211_MODE_AUTO &&
IEEE80211_IS_CHAN_B(c) &&
find11gchannel(ic, i, c->ic_freq))
continue;
/* Do not add channels already put into the scan list by the
* scan table - these have already been filtered by mode
* and for whether they are in the active channel list. */
if (checktable(staScanTable, c))
continue;
/* Make sure the channel is active */
if ((c == NULL) || isclr(ic->ic_chan_active, c->ic_ieee))
continue;
/* Don't overrun */
if (ss->ss_last >= IEEE80211_SCAN_MAX)
break;
ss->ss_chans[ss->ss_last++] = c;
}
ss->ss_next = 0;
/* XXX tunables */
ss->ss_mindwell = msecs_to_jiffies(200); /* 200ms */
ss->ss_maxdwell = msecs_to_jiffies(300); /* 300ms */
#ifdef IEEE80211_DEBUG
if (ieee80211_msg_scan(vap)) {
printk("%s: scan set ", vap->iv_dev->name);
ieee80211_scan_dump_channels(ss);
printk(" dwell min %ld max %ld\n",
ss->ss_mindwell, ss->ss_maxdwell);
}
#endif /* IEEE80211_DEBUG */
as->as_newscan = 1;
SCAN_AP_UNLOCK_IRQ(as);
return 0;
}
/*
* Restart a bg scan.
*/
static int
ap_restart(struct ieee80211_scan_state *ss, struct ieee80211vap *vap)
{
struct ap_state *as = ss->ss_priv;
as->as_newscan = 1;
return 0;
}
/*
* Cancel an ongoing scan.
*/
static int
ap_cancel(struct ieee80211_scan_state *ss, struct ieee80211vap *vap)
{
struct ap_state *as = ss->ss_priv;
IEEE80211_CANCEL_TQUEUE(&as->as_actiontq);
return 0;
}
/*
* Record max rssi on channel.
*/
static int
ap_add(struct ieee80211_scan_state *ss, const struct ieee80211_scanparams *sp,
const struct ieee80211_frame *wh, int subtype, int rssi, u_int64_t rtsf)
{
struct ap_state *as = ss->ss_priv;
const u_int8_t *macaddr = wh->i_addr2;
struct ieee80211vap *vap = ss->ss_vap;
struct ieee80211com *ic = vap->iv_ic;
struct scan_entry *se = NULL;
struct ieee80211_scan_entry *ise = NULL;
int hash = AP_HASH(macaddr);
int chan;
/* This section provides scan results to wireless extensions */
SCAN_AP_LOCK_IRQ(as);
chan = ieee80211_chan2ieee(ic, ic->ic_curchan);
/* This is the only information used for channel selection by AP */
if (rssi > as->as_maxrssi[chan])
as->as_maxrssi[chan] = rssi;
LIST_FOREACH(se, &as->as_hash[hash], se_hash)
if (IEEE80211_ADDR_EQ(se->base.se_macaddr, macaddr) &&
(sp->ssid[1] == se->base.se_ssid[1]) &&
!memcmp(se->base.se_ssid + 2, sp->ssid + 2,
se->base.se_ssid[1]))
goto found;
MALLOC(se, struct scan_entry *, sizeof(struct scan_entry),
M_80211_SCAN, M_NOWAIT | M_ZERO);
if (se == NULL) {
SCAN_AP_UNLOCK_IRQ_EARLY(as);
return 0;
}
se->se_scangen = as->as_scangen-1;
IEEE80211_ADDR_COPY(se->base.se_macaddr, macaddr);
TAILQ_INSERT_TAIL(&as->as_entry, se, se_list);
LIST_INSERT_HEAD(&as->as_hash[hash], se, se_hash);
found:
ise = &se->base;
/* XXX: AP beaconing multiple SSID w/ same BSSID */
if ((sp->ssid[1] != 0) &&
((subtype == IEEE80211_FC0_SUBTYPE_PROBE_RESP) ||
(ise->se_ssid[1] == 0)))
memcpy(ise->se_ssid, sp->ssid, 2 + sp->ssid[1]);
memcpy(ise->se_rates, sp->rates,
IEEE80211_SANITISE_RATESIZE(2 + sp->rates[1]));
if (sp->xrates != NULL) {
memcpy(ise->se_xrates, sp->xrates,
IEEE80211_SANITISE_RATESIZE(2 + sp->xrates[1]));
} else
ise->se_xrates[1] = 0;
IEEE80211_ADDR_COPY(ise->se_bssid, wh->i_addr3);
/* Record RSSI data using extended precision LPF filter.*/
if (se->se_lastupdate == 0) /* First sample */
se->se_avgrssi = RSSI_IN(rssi);
else /* Avg. w/ previous samples */
RSSI_LPF(se->se_avgrssi, rssi);
se->base.se_rssi = RSSI_GET(se->se_avgrssi);
ise->se_rtsf = rtsf;
memcpy(ise->se_tstamp.data, sp->tstamp, sizeof(ise->se_tstamp));
ise->se_intval = sp->bintval;
ise->se_capinfo = sp->capinfo;
ise->se_chan = ic->ic_curchan;
ise->se_fhdwell = sp->fhdwell;
ise->se_fhindex = sp->fhindex;
ise->se_erp = sp->erp;
ise->se_timoff = sp->timoff;
if (sp->tim != NULL) {
const struct ieee80211_tim_ie *tim =
(const struct ieee80211_tim_ie *)sp->tim;
ise->se_dtimperiod = tim->tim_period;
}
saveie(&ise->se_wme_ie, sp->wme);
saveie(&ise->se_wpa_ie, sp->wpa);
saveie(&ise->se_rsn_ie, sp->rsn);
saveie(&ise->se_ath_ie, sp->ath);
se->se_lastupdate = jiffies; /* update time */
se->se_seen = 1;
se->se_notseen = 0;
SCAN_AP_UNLOCK_IRQ(as);
return 1;
}
struct pc_params {
struct ieee80211vap *vap;
struct ieee80211_scan_state *ss;
int flags;
};
struct channel {
struct ieee80211_channel *chan;
int orig;
struct pc_params *params;
};
/* This function must be invoked with locks acquired */
static int
pc_cmp_radar(struct ieee80211_channel *a, struct ieee80211_channel *b)
{
/* a is better than b (return < 0) when b is marked while a is not */
return !!IEEE80211_IS_CHAN_RADAR(a) - !!IEEE80211_IS_CHAN_RADAR(b);
}
/* This function must be invoked with locks acquired */
static int
pc_cmp_keepmode(struct pc_params *params, struct ieee80211_channel *a,
struct ieee80211_channel *b)
{
struct ieee80211com *ic = params->vap->iv_ic;
struct ieee80211_channel *cur = ic->ic_bsschan;
if (!(params->flags & IEEE80211_SCAN_KEEPMODE))
return 0;
/* a is better than b (return < 0) when (a, cur) have the same mode
* and (b, cur) do not. */
return
!!IEEE80211_ARE_CHANS_SAME_MODE(b, cur) -
!!IEEE80211_ARE_CHANS_SAME_MODE(a, cur);
}
/* This function must be invoked with locks acquired */
static int
pc_cmp_sc(struct ieee80211com *ic, struct ieee80211_channel *a,
struct ieee80211_channel *b)
{
/* a is better than b (return < 0) when a has more chan nodes than b */
return
ic->ic_chan_nodes[b->ic_ieee] -
ic->ic_chan_nodes[a->ic_ieee];
}
/* This function must be invoked with locks acquired */
static int
pc_cmp_rssi(struct ap_state *as, struct ieee80211_channel *a,
struct ieee80211_channel *b)
{
/* a is better than b (return < 0) when a has rssi less than b */
return
as->as_maxrssi[a->ic_ieee] -
as->as_maxrssi[b->ic_ieee];
}
/* This function must be invoked with locks acquired */
static int
pc_cmp_samechan(struct ieee80211com *ic, struct ieee80211_channel *a,
struct ieee80211_channel *b)
{
struct ieee80211_channel *ic_bsschan = ic->ic_bsschan;
if (ic_bsschan == IEEE80211_CHAN_ANYC)
return 0;
/* a is better than b (return < 0) when a is current (and b is not) */
return (b == ic_bsschan) - (a == ic_bsschan);
}
/* This function must be invoked with locks acquired */
static int
pc_cmp_orig(struct channel *a, struct channel *b)
{
return a->orig - b->orig;
}
/* This function must be invoked with locks acquired */
static int
pc_cmp(const void *_a, const void *_b)
{
struct ieee80211_channel *a = ((struct channel *)_a)->chan;
struct ieee80211_channel *b = ((struct channel *)_b)->chan;
struct pc_params *params = ((struct channel *)_a)->params;
struct ieee80211com *ic = params->vap->iv_ic;
int res;
#define EVALUATE_CRITERION(name, ...) do { \
if ((res = pc_cmp_##name(__VA_ARGS__)) != 0) \
return res; \
} while (0)
EVALUATE_CRITERION(radar, a, b);
EVALUATE_CRITERION(keepmode, params, a, b);
EVALUATE_CRITERION(sc, ic, a, b);
/* XXX: rssi useless? pick_channel evaluates it anyway */
EVALUATE_CRITERION(rssi, params->ss->ss_priv, a, b);
EVALUATE_CRITERION(samechan, ic, a, b);
EVALUATE_CRITERION(orig, (struct channel *)_a, (struct channel *)_b);
#undef EVALUATE_CRITERION
return res;
}
/* This function must be invoked with locks acquired */
static void
pc_swap(void *a, void *b, int n)
{
struct ieee80211_channel *t = ((struct channel *)a)->chan;
int i;
((struct channel *)a)->chan = ((struct channel *)b)->chan;
((struct channel *)b)->chan = t;
i = ((struct channel *)a)->orig;
((struct channel *)a)->orig = ((struct channel *)b)->orig;
((struct channel *)b)->orig = i;
/* (struct channel *)x->params doesn't have to be swapped, because it
* is the same across all channels */
}
/* Pick a quiet channel to use for ap operation.
* Must be invoked while we hold the locks. */
static struct ieee80211_channel *
pick_channel(struct ieee80211_scan_state *ss, struct ieee80211vap *vap,
u_int32_t flags)
{
struct ieee80211com *ic = vap->iv_ic;
unsigned int i, best_rssi;
int ss_last = ss->ss_last;
struct ieee80211_channel *best;
struct ap_state *as = ss->ss_priv;
struct channel chans[ss_last]; /* actually ss_last-1 is required */
struct channel *c = NULL;
struct pc_params params = { vap, ss, flags };
int benefit = 0;
int sta_assoc = 0;
for (i = 0; i < ss_last; i++) {
chans[i].chan = ss->ss_chans[i];
chans[i].orig = i;
chans[i].params = &params;
}
sort(chans, ss_last, sizeof(*chans), pc_cmp, pc_swap);
#ifdef IEEE80211_DEBUG
for (i = 0; i < ss_last; i++) {
int chan = ieee80211_chan2ieee(ic, chans[i].chan);
IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: channel %u, "
"rssi %d, radar %d, cn %d, km %d\n",
__func__, chan, as->as_maxrssi[chan],
IEEE80211_IS_CHAN_RADAR(chans[i].chan),
ic->ic_chan_nodes[chans[i].chan->ic_ieee],
!!IEEE80211_ARE_CHANS_SAME_MODE(chans[i].chan,
ic->ic_bsschan));
}
#endif /* IEEE80211_DEBUG */
best = NULL;
best_rssi = 0xff; /* If signal is bigger than 0xff, we'd be melting. */
for (i = 0; i < ss_last; i++) {
c = &chans[i];
benefit = best_rssi - as->as_maxrssi[c->chan->ic_ieee];
sta_assoc = ic->ic_sta_assoc;
/* Don't switch... */
if (benefit <= 0)
continue;
/* Verify channel is not marked for non-occupancy */
if (IEEE80211_IS_CHAN_RADAR(c->chan) &&
(ic->ic_flags & IEEE80211_F_DOTH))
continue;
/* Do not select 802.11a ST if mode is specified and is not
* 802.11a ST */
if (as->as_required_mode &&
IEEE80211_IS_CHAN_STURBO(c->chan) &&
(as->as_vap_desired_mode != IEEE80211_MODE_TURBO_STATIC_A))
continue;
/* Verify mode matches any fixed mode specified */
if ((c->chan->ic_flags & as->as_required_mode) !=
as->as_required_mode)
continue;
if ((ic->ic_bsschan != NULL) &&
(ic->ic_bsschan != IEEE80211_CHAN_ANYC)) {
/* Make sure the channels are the same mode */
if ((flags & IEEE80211_SCAN_KEEPMODE) &&
!IEEE80211_ARE_CHANS_SAME_MODE(c->chan,
ic->ic_bsschan))
/* break the loop as the subsequent chans won't be
* better */
break;
if (!IEEE80211_ARE_CHANS_SAME_MODE(c->chan,
ic->ic_bsschan))
/* break the loop as the subsequent chans won't be
* better */
break;
}
if (sta_assoc != 0) {
int sl = ic->ic_cn_total -
ic->ic_chan_nodes[c->chan->ic_ieee]; /* count */
if (ic->ic_sc_algorithm == IEEE80211_SC_LOOSE) {
int sl_max = ic->ic_sc_sldg * benefit;
sl = 1000 * sl / sta_assoc; /* permil */
IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
"%s: chan %d, dB gained: %d, "
"STAs lost: %d permil (max %d)\n",
__func__, c->chan->ic_ieee,
benefit, sl, sl_max);
if (sl > sl_max)
continue;
} else if (((ic->ic_sc_algorithm ==
IEEE80211_SC_TIGHT) ||
(ic->ic_sc_algorithm ==
IEEE80211_SC_STRICT)) &&
(sl > 0)) {
/* Break the loop as the subsequent chans
* won't be better. */
break;
}
}
best = c->chan;
best_rssi = as->as_maxrssi[best->ic_ieee];
}
if (best != NULL) {
i = best->ic_ieee;
IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
"%s: best: channel %u rssi %d\n",
__func__, i, as->as_maxrssi[i]);
}
return best;
}
static int
ap_end(struct ieee80211_scan_state *ss, struct ieee80211vap *vap,
int (*action)(struct ieee80211vap *,
const struct ieee80211_scan_entry *),
u_int32_t flags)
{
struct ap_state *as = ss->ss_priv;
struct ieee80211_channel *bestchan = NULL;
struct ieee80211com *ic = NULL;
int res = 1;
SCAN_AP_LOCK_IRQ(as);
KASSERT(vap->iv_opmode == IEEE80211_M_HOSTAP,
("wrong opmode %u", vap->iv_opmode));
ic = vap->iv_ic;
bestchan = pick_channel(ss, vap, flags);
if (bestchan == NULL) {
if (ss->ss_last > 0) {
/* no suitable channel, should not happen */
printk(KERN_ERR "%s: %s: no suitable channel! "
"(should not happen)\n",
DEV_NAME(vap->iv_dev), __func__);
}
res = 1; /* Do NOT restart scan */
} else {
struct ieee80211_scan_entry se;
/* XXX: notify all VAPs? */
/* if this is a dynamic turbo frequency , start with normal
* mode first */
if (IEEE80211_IS_CHAN_TURBO(bestchan) &&
!IEEE80211_IS_CHAN_STURBO(bestchan)) {
if ((bestchan = ieee80211_find_channel(ic,
bestchan->ic_freq, bestchan->ic_flags &
~IEEE80211_CHAN_TURBO)) == NULL) {
/* should never happen ?? */
SCAN_AP_UNLOCK_IRQ_EARLY(as);
return 0;
}
}
memset(&se, 0, sizeof(se));
se.se_chan = bestchan;
as->as_action = ss->ss_ops->scan_default;
if (action)
as->as_action = action;
as->as_selbss = se;
/* Must defer action to avoid possible recursive call through
* 80211 state machine, which would result in recursive
* locking. */
IEEE80211_SCHEDULE_TQUEUE(&as->as_actiontq);
res = 1;
}
SCAN_AP_UNLOCK_IRQ(as);
return res;
}
static void
ap_age(struct ieee80211_scan_state *ss)
{
struct ap_state *as = ss->ss_priv;
struct scan_entry *se, *next;
SCAN_AP_LOCK_IRQ(as);
TAILQ_FOREACH_SAFE(se, &as->as_entry, se_list, next) {
if (se->se_notseen > AP_PURGE_SCANS) {
TAILQ_REMOVE(&as->as_entry, se, se_list);
LIST_REMOVE(se, se_hash);
FREE(se, M_80211_SCAN);
}
}
SCAN_AP_UNLOCK_IRQ(as);
}
static int
ap_iterate(struct ieee80211_scan_state *ss,
ieee80211_scan_iter_func *f, void *arg)
{
struct ap_state *as = ss->ss_priv;
struct scan_entry *se;
u_int gen;
int res = 0;
SCAN_AP_GEN_LOCK(as);
gen = as->as_scangen++;
restart:
SCAN_AP_LOCK_IRQ(as);
TAILQ_FOREACH(se, &as->as_entry, se_list) {
if (se->se_scangen != gen) {
se->se_scangen = gen;
/* update public state */
se->base.se_age = jiffies - se->se_lastupdate;
SCAN_AP_UNLOCK_IRQ_EARLY(as);
res = (*f)(arg, &se->base);
/* We probably ran out of buffer space. */
if (res != 0)
goto done;
goto restart;
}
}
SCAN_AP_UNLOCK_IRQ(as);
done:
SCAN_AP_GEN_UNLOCK(as);
return res;
}
static void
ap_assoc_success(struct ieee80211_scan_state *ss,
const u_int8_t macaddr[IEEE80211_ADDR_LEN])
{
/* should not be called */
}
static void
ap_assoc_fail(struct ieee80211_scan_state *ss,
const u_int8_t macaddr[IEEE80211_ADDR_LEN], int reason)
{
/* should not be called */
}
/*
* Default action to execute when a scan entry is found for ap
* mode. Return 1 on success, 0 on failure
*/
static int
ap_default_action(struct ieee80211vap *vap,
const struct ieee80211_scan_entry *se)
{
ieee80211_create_ibss(vap, se->se_chan);
return 1;
}
static void
action_tasklet(IEEE80211_TQUEUE_ARG data)
{
struct ieee80211_scan_state *ss = (struct ieee80211_scan_state *)data;
struct ap_state *as = (struct ap_state *)ss->ss_priv;
struct ieee80211vap *vap = ss->ss_vap;
SCAN_AP_LOCK_IRQ(as);
if (as->as_newscan) {
struct scan_entry *se;
TAILQ_FOREACH(se, &as->as_entry, se_list) {
/*
* If seen then reset and don't bump the count;
* otherwise bump the ``not seen'' count. Note
* that this ensures that stations for which we
* see frames while not scanning but not during
* this scan will not be penalized.
*/
if (se->se_seen)
se->se_seen = 0;
else
se->se_notseen++;
}
as->as_newscan = 0;
}
SCAN_AP_UNLOCK_IRQ(as);
(*ss->ss_ops->scan_default)(vap, &as->as_selbss);
}
/*
* Module glue.
*/
MODULE_AUTHOR("Errno Consulting, Sam Leffler");
MODULE_DESCRIPTION("802.11 wireless support: default ap scanner");
#ifdef MODULE_LICENSE
MODULE_LICENSE("Dual BSD/GPL");
#endif
static const struct ieee80211_scanner ap_default = {
.scan_name = "default",
.scan_attach = ap_attach,
.scan_detach = ap_detach,
.scan_start = ap_start,
.scan_restart = ap_restart,
.scan_cancel = ap_cancel,
.scan_end = ap_end,
.scan_flush = ap_flush,
.scan_add = ap_add,
.scan_age = ap_age,
.scan_iterate = ap_iterate,
.scan_assoc_success = ap_assoc_success,
.scan_assoc_fail = ap_assoc_fail,
.scan_default = ap_default_action,
};
static int __init
init_scanner_ap(void)
{
ieee80211_scanner_register(IEEE80211_M_HOSTAP, &ap_default);
return 0;
}
module_init(init_scanner_ap);
static void __exit
exit_scanner_ap(void)
{
ieee80211_scanner_unregister_all(&ap_default);
}
module_exit(exit_scanner_ap);
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