freebsd-skq/sys/net80211/ieee80211_scan_sta.c
Sam Leffler 5773d80e69 Correct handling of off-channel frames:
o do not override the home channel recorded for the sta when the frame is
  received off-channel; this fixes a problem where we might think the sta
  was operating on the channel the frame was received on causing association
  requests to be ignored/rejected (likely cause of kern/99036)
o don't include rssi of off-channel frames in the avg rssi used to select
  a bss; this gives us a better estimate of the signal we will see for the
  station when on-channel

PR:		kern/99036
Found by:	Yubin Gong
Reviewed by:	sephe
MFC after:	1 week
2007-11-05 17:24:28 +00:00

1478 lines
40 KiB
C

/*-
* Copyright (c) 2002-2007 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.
* 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.
*
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* IEEE 802.11 station scanning support.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/socket.h>
#include <net/if.h>
#include <net/if_media.h>
#include <net/ethernet.h>
#include <net80211/ieee80211_var.h>
#include <net/bpf.h>
/*
* Parameters for managing cache entries:
*
* o a station with STA_FAILS_MAX failures is not considered
* when picking a candidate
* o a station that hasn't had an update in STA_PURGE_SCANS
* (background) scans is discarded
* o after STA_FAILS_AGE seconds we clear the failure count
*/
#define STA_FAILS_MAX 2 /* assoc failures before ignored */
#define STA_FAILS_AGE (2*60) /* time before clearing fails (secs) */
#define STA_PURGE_SCANS 2 /* age for purging entries (scans) */
/* XXX tunable */
#define STA_RSSI_MIN 8 /* min acceptable rssi */
#define STA_RSSI_MAX 40 /* max rssi for comparison */
#define RSSI_LPF_LEN 10
#define RSSI_DUMMY_MARKER 0x127
#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 != RSSI_DUMMY_MARKER) ? (((x) * ((len) - 1) + (y)) / (len)) : (y))
#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)
struct sta_entry {
struct ieee80211_scan_entry base;
TAILQ_ENTRY(sta_entry) se_list;
LIST_ENTRY(sta_entry) se_hash;
uint8_t se_fails; /* failure to associate count */
uint8_t se_seen; /* seen during current scan */
uint8_t se_notseen; /* not seen in previous scans */
uint8_t se_flags;
uint32_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# */
};
#define STA_HASHSIZE 32
/* simple hash is enough for variation of macaddr */
#define STA_HASH(addr) \
(((const uint8_t *)(addr))[IEEE80211_ADDR_LEN - 1] % STA_HASHSIZE)
struct sta_table {
struct mtx st_lock; /* on scan table */
TAILQ_HEAD(, sta_entry) st_entry; /* all entries */
LIST_HEAD(, sta_entry) st_hash[STA_HASHSIZE];
struct mtx st_scanlock; /* on st_scangen */
u_int st_scangen; /* gen# for iterator */
int st_newscan;
};
static void sta_flush_table(struct sta_table *);
/*
* match_bss returns a bitmask describing if an entry is suitable
* for use. If non-zero the entry was deemed not suitable and it's
* contents explains why. The following flags are or'd to to this
* mask and can be used to figure out why the entry was rejected.
*/
#define MATCH_CHANNEL 0x001 /* channel mismatch */
#define MATCH_CAPINFO 0x002 /* capabilities mismatch, e.g. no ess */
#define MATCH_PRIVACY 0x004 /* privacy mismatch */
#define MATCH_RATE 0x008 /* rate set mismatch */
#define MATCH_SSID 0x010 /* ssid mismatch */
#define MATCH_BSSID 0x020 /* bssid mismatch */
#define MATCH_FAILS 0x040 /* too many failed auth attempts */
#define MATCH_NOTSEEN 0x080 /* not seen in recent scans */
#define MATCH_RSSI 0x100 /* rssi deemed too low to use */
static int match_bss(struct ieee80211com *,
const struct ieee80211_scan_state *, struct sta_entry *, int);
/* number of references from net80211 layer */
static int nrefs = 0;
/*
* Attach prior to any scanning work.
*/
static int
sta_attach(struct ieee80211_scan_state *ss)
{
struct sta_table *st;
MALLOC(st, struct sta_table *, sizeof(struct sta_table),
M_80211_SCAN, M_NOWAIT | M_ZERO);
if (st == NULL)
return 0;
mtx_init(&st->st_lock, "scantable", "802.11 scan table", MTX_DEF);
mtx_init(&st->st_scanlock, "scangen", "802.11 scangen", MTX_DEF);
TAILQ_INIT(&st->st_entry);
ss->ss_priv = st;
nrefs++; /* NB: we assume caller locking */
return 1;
}
/*
* Cleanup any private state.
*/
static int
sta_detach(struct ieee80211_scan_state *ss)
{
struct sta_table *st = ss->ss_priv;
if (st != NULL) {
sta_flush_table(st);
mtx_destroy(&st->st_lock);
mtx_destroy(&st->st_scanlock);
FREE(st, M_80211_SCAN);
KASSERT(nrefs > 0, ("imbalanced attach/detach"));
nrefs--; /* NB: we assume caller locking */
}
return 1;
}
/*
* Flush all per-scan state.
*/
static int
sta_flush(struct ieee80211_scan_state *ss)
{
struct sta_table *st = ss->ss_priv;
mtx_lock(&st->st_lock);
sta_flush_table(st);
mtx_unlock(&st->st_lock);
ss->ss_last = 0;
return 0;
}
/*
* Flush all entries in the scan cache.
*/
static void
sta_flush_table(struct sta_table *st)
{
struct sta_entry *se, *next;
TAILQ_FOREACH_SAFE(se, &st->st_entry, se_list, next) {
TAILQ_REMOVE(&st->st_entry, se, se_list);
LIST_REMOVE(se, se_hash);
FREE(se, M_80211_SCAN);
}
}
static void
saveie(uint8_t **iep, const uint8_t *ie)
{
if (ie == NULL)
*iep = NULL;
else
ieee80211_saveie(iep, ie);
}
/*
* Process a beacon or probe response frame; create an
* entry in the scan cache or update any previous entry.
*/
static int
sta_add(struct ieee80211_scan_state *ss,
const struct ieee80211_scanparams *sp,
const struct ieee80211_frame *wh,
int subtype, int rssi, int noise, int rstamp)
{
#define ISPROBE(_st) ((_st) == IEEE80211_FC0_SUBTYPE_PROBE_RESP)
#define PICK1ST(_ss) \
((ss->ss_flags & (IEEE80211_SCAN_PICK1ST | IEEE80211_SCAN_GOTPICK)) == \
IEEE80211_SCAN_PICK1ST)
struct sta_table *st = ss->ss_priv;
const uint8_t *macaddr = wh->i_addr2;
struct ieee80211com *ic = ss->ss_ic;
struct sta_entry *se;
struct ieee80211_scan_entry *ise;
int hash, offchan;
hash = STA_HASH(macaddr);
mtx_lock(&st->st_lock);
LIST_FOREACH(se, &st->st_hash[hash], se_hash)
if (IEEE80211_ADDR_EQ(se->base.se_macaddr, macaddr))
goto found;
MALLOC(se, struct sta_entry *, sizeof(struct sta_entry),
M_80211_SCAN, M_NOWAIT | M_ZERO);
if (se == NULL) {
mtx_unlock(&st->st_lock);
return 0;
}
se->se_scangen = st->st_scangen-1;
se->se_avgrssi = RSSI_DUMMY_MARKER;
IEEE80211_ADDR_COPY(se->base.se_macaddr, macaddr);
TAILQ_INSERT_TAIL(&st->st_entry, se, se_list);
LIST_INSERT_HEAD(&st->st_hash[hash], se, se_hash);
found:
ise = &se->base;
/* XXX ap beaconing multiple ssid w/ same bssid */
if (sp->ssid[1] != 0 &&
(ISPROBE(subtype) || ise->se_ssid[1] == 0))
memcpy(ise->se_ssid, sp->ssid, 2+sp->ssid[1]);
KASSERT(sp->rates[1] <= IEEE80211_RATE_MAXSIZE,
("rate set too large: %u", sp->rates[1]));
memcpy(ise->se_rates, sp->rates, 2+sp->rates[1]);
if (sp->xrates != NULL) {
/* XXX validate xrates[1] */
KASSERT(sp->xrates[1] + sp->rates[1] <= IEEE80211_RATE_MAXSIZE,
("xrate set too large: %u", sp->xrates[1]));
memcpy(ise->se_xrates, sp->xrates, 2+sp->xrates[1]);
} else
ise->se_xrates[1] = 0;
IEEE80211_ADDR_COPY(ise->se_bssid, wh->i_addr3);
offchan = (IEEE80211_CHAN2IEEE(sp->curchan) != sp->bchan &&
ic->ic_phytype != IEEE80211_T_FH);
if (!offchan) {
/*
* Record rssi data using extended precision LPF filter.
*
* NB: use only on-channel data to insure we get a good
* estimate of the signal we'll see when associated.
*/
RSSI_LPF(se->se_avgrssi, rssi);
ise->se_rssi = RSSI_GET(se->se_avgrssi);
ise->se_noise = noise;
}
ise->se_rstamp = rstamp;
memcpy(ise->se_tstamp.data, sp->tstamp, sizeof(ise->se_tstamp));
ise->se_intval = sp->bintval;
ise->se_capinfo = sp->capinfo;
/*
* Beware of overriding se_chan for frames seen
* off-channel; this can cause us to attempt an
* assocation on the wrong channel.
*/
if (ise->se_chan == NULL || !offchan) {
/*
* NB: this is not right when the frame is received
* off-channel but se_chan is assumed set by code
* elsewhere so we must assign something; the scan
* entry should be ignored because the rssi will be
* zero (because the frames are received off-channel).
*
* We could locate the correct channel using sp->chan
* but it's not clear we should join an ap that we
* never see on-channel during a scan.
*/
ise->se_chan = sp->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);
saveie(&ise->se_htcap_ie, sp->htcap);
saveie(&ise->se_htinfo_ie, sp->htinfo);
/* clear failure count after STA_FAIL_AGE passes */
if (se->se_fails && (ticks - se->se_lastfail) > STA_FAILS_AGE*hz) {
se->se_fails = 0;
IEEE80211_NOTE_MAC(ic, IEEE80211_MSG_SCAN, macaddr,
"%s: fails %u", __func__, se->se_fails);
}
se->se_lastupdate = ticks; /* update time */
se->se_seen = 1;
se->se_notseen = 0;
mtx_unlock(&st->st_lock);
/*
* If looking for a quick choice and nothing's
* been found check here.
*/
if (PICK1ST(ss) && match_bss(ic, ss, se, IEEE80211_MSG_SCAN) == 0)
ss->ss_flags |= IEEE80211_SCAN_GOTPICK;
return 1;
#undef PICK1ST
#undef ISPROBE
}
/*
* Check if a channel is excluded by user request.
*/
static int
isexcluded(struct ieee80211com *ic, const struct ieee80211_channel *c)
{
return (isclr(ic->ic_chan_active, c->ic_ieee) ||
(ic->ic_des_chan != IEEE80211_CHAN_ANYC &&
c->ic_freq != ic->ic_des_chan->ic_freq));
}
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;
}
static const u_int chanflags[IEEE80211_MODE_MAX] = {
IEEE80211_CHAN_B, /* IEEE80211_MODE_AUTO */
IEEE80211_CHAN_A, /* IEEE80211_MODE_11A */
IEEE80211_CHAN_B, /* IEEE80211_MODE_11B */
IEEE80211_CHAN_G, /* IEEE80211_MODE_11G */
IEEE80211_CHAN_FHSS, /* IEEE80211_MODE_FH */
IEEE80211_CHAN_A, /* IEEE80211_MODE_TURBO_A (check base channel)*/
IEEE80211_CHAN_G, /* IEEE80211_MODE_TURBO_G */
IEEE80211_CHAN_ST, /* IEEE80211_MODE_STURBO_A */
IEEE80211_CHAN_A, /* IEEE80211_MODE_11NA (check legacy) */
IEEE80211_CHAN_G, /* IEEE80211_MODE_11NG (check legacy) */
};
static void
add_channels(struct ieee80211com *ic,
struct ieee80211_scan_state *ss,
enum ieee80211_phymode mode, const uint16_t freq[], int nfreq)
{
#define N(a) (sizeof(a) / sizeof(a[0]))
struct ieee80211_channel *c, *cg;
u_int modeflags;
int i;
KASSERT(mode < N(chanflags), ("Unexpected mode %u", mode));
modeflags = chanflags[mode];
for (i = 0; i < nfreq; i++) {
if (ss->ss_last >= IEEE80211_SCAN_MAX)
break;
c = ieee80211_find_channel(ic, freq[i], modeflags);
if (c != NULL && isexcluded(ic, c))
continue;
if (mode == IEEE80211_MODE_AUTO) {
/*
* XXX special-case 11b/g channels so we select
* the g channel if both are present or there
* are only g channels.
*/
if (c == NULL || IEEE80211_IS_CHAN_B(c)) {
cg = find11gchannel(ic, i, freq[i]);
if (cg != NULL)
c = cg;
}
}
if (c == NULL)
continue;
ss->ss_chans[ss->ss_last++] = c;
}
#undef N
}
static const uint16_t rcl1[] = /* 8 FCC channel: 52, 56, 60, 64, 36, 40, 44, 48 */
{ 5260, 5280, 5300, 5320, 5180, 5200, 5220, 5240 };
static const uint16_t rcl2[] = /* 4 MKK channels: 34, 38, 42, 46 */
{ 5170, 5190, 5210, 5230 };
static const uint16_t rcl3[] = /* 2.4Ghz ch: 1,6,11,7,13 */
{ 2412, 2437, 2462, 2442, 2472 };
static const uint16_t rcl4[] = /* 5 FCC channel: 149, 153, 161, 165 */
{ 5745, 5765, 5785, 5805, 5825 };
static const uint16_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 uint16_t rcl8[] = /* 2.4Ghz ch: 2,3,4,5,8,9,10,12 */
{ 2417, 2422, 2427, 2432, 2447, 2452, 2457, 2467 };
static const uint16_t rcl9[] = /* 2.4Ghz ch: 14 */
{ 2484 };
static const uint16_t rcl10[] = /* Added Korean channels 2312-2372 */
{ 2312, 2317, 2322, 2327, 2332, 2337, 2342, 2347, 2352, 2357, 2362, 2367, 2372 };
static const uint16_t rcl11[] = /* Added Japan channels in 4.9/5.0 spectrum */
{ 5040, 5060, 5080, 4920, 4940, 4960, 4980 };
#ifdef ATH_TURBO_SCAN
static const uint16_t rcl5[] = /* 3 static turbo channels */
{ 5210, 5250, 5290 };
static const uint16_t rcl6[] = /* 2 static turbo channels */
{ 5760, 5800 };
static const uint16_t rcl6x[] = /* 4 FCC3 turbo channels */
{ 5540, 5580, 5620, 5660 };
static const uint16_t rcl12[] = /* 2.4Ghz Turbo channel 6 */
{ 2437 };
static const uint16_t rcl13[] = /* dynamic Turbo channels */
{ 5200, 5240, 5280, 5765, 5805 };
#endif /* ATH_TURBO_SCAN */
struct scanlist {
uint16_t mode;
uint16_t count;
const uint16_t *list;
};
#define X(a) .count = sizeof(a)/sizeof(a[0]), .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_STURBO_A, X(rcl5) },
{ IEEE80211_MODE_STURBO_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 }
};
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;
}
/*
* Start a station-mode scan by populating the channel list.
*/
static int
sta_start(struct ieee80211_scan_state *ss, struct ieee80211com *ic)
{
#define N(a) (sizeof(a)/sizeof(a[0]))
struct sta_table *st = ss->ss_priv;
const struct scanlist *scan;
enum ieee80211_phymode mode;
struct ieee80211_channel *c;
int i;
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 (scan = staScanTable; scan->list != NULL; scan++) {
mode = scan->mode;
if (ic->ic_des_mode != IEEE80211_MODE_AUTO) {
/*
* If a desired mode was specified, scan only
* channels that satisfy that constraint.
*/
if (ic->ic_des_mode != 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 (ic->ic_des_mode != IEEE80211_MODE_11G ||
mode != IEEE80211_MODE_11B)
continue;
mode = IEEE80211_MODE_11G; /* upgrade */
}
} else {
/*
* This lets add_channels upgrade an 11b channel
* to 11g if available.
*/
if (mode == IEEE80211_MODE_11B)
mode = IEEE80211_MODE_AUTO;
}
#ifdef IEEE80211_F_XR
/* XR does not operate on turbo channels */
if ((ic->ic_flags & IEEE80211_F_XR) &&
(mode == IEEE80211_MODE_TURBO_A ||
mode == IEEE80211_MODE_TURBO_G ||
mode == IEEE80211_MODE_STURBO_A))
continue;
#endif
/*
* Add the list of the channels; any that are not
* in the master channel list will be discarded.
*/
add_channels(ic, ss, mode, scan->list, scan->count);
}
/*
* Add the channels from the ic (from HAL) that are not present
* in the staScanTable.
*/
for (i = 0; i < ic->ic_nchans; i++) {
if (ss->ss_last >= IEEE80211_SCAN_MAX)
break;
c = &ic->ic_channels[i];
/*
* Ignore dynamic turbo channels; we scan them
* in normal mode (i.e. not boosted). Likewise
* for HT channels, they get scanned using
* legacy rates.
*/
if (IEEE80211_IS_CHAN_DTURBO(c) || IEEE80211_IS_CHAN_HT(c))
continue;
/*
* If a desired mode was specified, scan only
* channels that satisfy that constraint.
*/
if (ic->ic_des_mode != IEEE80211_MODE_AUTO &&
ic->ic_des_mode != ieee80211_chan2mode(c))
continue;
/*
* Skip channels excluded by user request.
*/
if (isexcluded(ic, c))
continue;
/*
* Add the channel unless it is listed in the
* fixed scan order tables. This insures we
* don't sweep back in channels we filtered out
* above.
*/
if (checktable(staScanTable, c))
continue;
/* Add channel to scanning list. */
ss->ss_chans[ss->ss_last++] = c;
}
ss->ss_next = 0;
/* XXX tunables */
ss->ss_mindwell = msecs_to_ticks(20); /* 20ms */
ss->ss_maxdwell = msecs_to_ticks(200); /* 200ms */
#ifdef IEEE80211_DEBUG
if (ieee80211_msg_scan(ic)) {
if_printf(ic->ic_ifp, "scan set ");
ieee80211_scan_dump_channels(ss);
printf(" dwell min %ld max %ld\n",
ss->ss_mindwell, ss->ss_maxdwell);
}
#endif /* IEEE80211_DEBUG */
st->st_newscan = 1;
return 0;
#undef N
}
/*
* Restart a bg scan.
*/
static int
sta_restart(struct ieee80211_scan_state *ss, struct ieee80211com *ic)
{
struct sta_table *st = ss->ss_priv;
st->st_newscan = 1;
return 0;
}
/*
* Cancel an ongoing scan.
*/
static int
sta_cancel(struct ieee80211_scan_state *ss, struct ieee80211com *ic)
{
return 0;
}
static uint8_t
maxrate(const struct ieee80211_scan_entry *se)
{
uint8_t rmax, r;
int i;
rmax = 0;
for (i = 0; i < se->se_rates[1]; i++) {
r = se->se_rates[2+i] & IEEE80211_RATE_VAL;
if (r > rmax)
rmax = r;
}
for (i = 0; i < se->se_xrates[1]; i++) {
r = se->se_xrates[2+i] & IEEE80211_RATE_VAL;
if (r > rmax)
rmax = r;
}
return rmax;
}
/*
* Compare the capabilities of two entries and decide which is
* more desirable (return >0 if a is considered better). Note
* that we assume compatibility/usability has already been checked
* so we don't need to (e.g. validate whether privacy is supported).
* Used to select the best scan candidate for association in a BSS.
*/
static int
sta_compare(const struct sta_entry *a, const struct sta_entry *b)
{
#define PREFER(_a,_b,_what) do { \
if (((_a) ^ (_b)) & (_what)) \
return ((_a) & (_what)) ? 1 : -1; \
} while (0)
uint8_t maxa, maxb;
int8_t rssia, rssib;
int weight;
/* privacy support */
PREFER(a->base.se_capinfo, b->base.se_capinfo,
IEEE80211_CAPINFO_PRIVACY);
/* compare count of previous failures */
weight = b->se_fails - a->se_fails;
if (abs(weight) > 1)
return weight;
/*
* Compare rssi. If the two are considered equivalent
* then fallback to other criteria. We threshold the
* comparisons to avoid selecting an ap purely by rssi
* when both values may be good but one ap is otherwise
* more desirable (e.g. an 11b-only ap with stronger
* signal than an 11g ap).
*/
rssia = MIN(a->base.se_rssi, STA_RSSI_MAX);
rssib = MIN(b->base.se_rssi, STA_RSSI_MAX);
if (abs(rssib - rssia) < 5) {
/* best/max rate preferred if signal level close enough XXX */
maxa = maxrate(&a->base);
maxb = maxrate(&b->base);
if (maxa != maxb)
return maxa - maxb;
/* XXX use freq for channel preference */
/* for now just prefer 5Ghz band to all other bands */
if (IEEE80211_IS_CHAN_5GHZ(a->base.se_chan) &&
!IEEE80211_IS_CHAN_5GHZ(b->base.se_chan))
return 1;
if (!IEEE80211_IS_CHAN_5GHZ(a->base.se_chan) &&
IEEE80211_IS_CHAN_5GHZ(b->base.se_chan))
return -1;
}
/* all things being equal, use signal level */
return a->base.se_rssi - b->base.se_rssi;
#undef PREFER
}
/*
* Check rate set suitability and return the best supported rate.
*/
static int
check_rate(struct ieee80211com *ic, const struct ieee80211_scan_entry *se)
{
#define RV(v) ((v) & IEEE80211_RATE_VAL)
const struct ieee80211_rateset *srs;
int i, j, nrs, r, okrate, badrate, fixedrate;
const uint8_t *rs;
okrate = badrate = fixedrate = 0;
srs = ieee80211_get_suprates(ic, se->se_chan);
nrs = se->se_rates[1];
rs = se->se_rates+2;
fixedrate = IEEE80211_FIXED_RATE_NONE;
again:
for (i = 0; i < nrs; i++) {
r = RV(rs[i]);
badrate = r;
/*
* Check any fixed rate is included.
*/
if (r == ic->ic_fixed_rate)
fixedrate = r;
/*
* Check against our supported rates.
*/
for (j = 0; j < srs->rs_nrates; j++)
if (r == RV(srs->rs_rates[j])) {
if (r > okrate) /* NB: track max */
okrate = r;
break;
}
if (j == srs->rs_nrates && (rs[i] & IEEE80211_RATE_BASIC)) {
/*
* Don't try joining a BSS, if we don't support
* one of its basic rates.
*/
okrate = 0;
goto back;
}
}
if (rs == se->se_rates+2) {
/* scan xrates too; sort of an algol68-style for loop */
nrs = se->se_xrates[1];
rs = se->se_xrates+2;
goto again;
}
back:
if (okrate == 0 || ic->ic_fixed_rate != fixedrate)
return badrate | IEEE80211_RATE_BASIC;
else
return RV(okrate);
#undef RV
}
static int
match_ssid(const uint8_t *ie,
int nssid, const struct ieee80211_scan_ssid ssids[])
{
int i;
for (i = 0; i < nssid; i++) {
if (ie[1] == ssids[i].len &&
memcmp(ie+2, ssids[i].ssid, ie[1]) == 0)
return 1;
}
return 0;
}
/*
* Test a scan candidate for suitability/compatibility.
*/
static int
match_bss(struct ieee80211com *ic,
const struct ieee80211_scan_state *ss, struct sta_entry *se0,
int debug)
{
struct ieee80211_scan_entry *se = &se0->base;
uint8_t rate;
int fail;
fail = 0;
if (isclr(ic->ic_chan_active, ieee80211_chan2ieee(ic, se->se_chan)))
fail |= MATCH_CHANNEL;
/*
* NB: normally the desired mode is used to construct
* the channel list, but it's possible for the scan
* cache to include entries for stations outside this
* list so we check the desired mode here to weed them
* out.
*/
if (ic->ic_des_mode != IEEE80211_MODE_AUTO &&
(se->se_chan->ic_flags & IEEE80211_CHAN_ALLTURBO) !=
chanflags[ic->ic_des_mode])
fail |= MATCH_CHANNEL;
if (ic->ic_opmode == IEEE80211_M_IBSS) {
if ((se->se_capinfo & IEEE80211_CAPINFO_IBSS) == 0)
fail |= MATCH_CAPINFO;
} else {
if ((se->se_capinfo & IEEE80211_CAPINFO_ESS) == 0)
fail |= MATCH_CAPINFO;
}
if (ic->ic_flags & IEEE80211_F_PRIVACY) {
if ((se->se_capinfo & IEEE80211_CAPINFO_PRIVACY) == 0)
fail |= MATCH_PRIVACY;
} else {
/* XXX does this mean privacy is supported or required? */
if (se->se_capinfo & IEEE80211_CAPINFO_PRIVACY)
fail |= MATCH_PRIVACY;
}
rate = check_rate(ic, se);
if (rate & IEEE80211_RATE_BASIC)
fail |= MATCH_RATE;
if (ss->ss_nssid != 0 &&
!match_ssid(se->se_ssid, ss->ss_nssid, ss->ss_ssid))
fail |= MATCH_SSID;
if ((ic->ic_flags & IEEE80211_F_DESBSSID) &&
!IEEE80211_ADDR_EQ(ic->ic_des_bssid, se->se_bssid))
fail |= MATCH_BSSID;
if (se0->se_fails >= STA_FAILS_MAX)
fail |= MATCH_FAILS;
/* NB: entries may be present awaiting purge, skip */
if (se0->se_notseen >= STA_PURGE_SCANS)
fail |= MATCH_NOTSEEN;
if (se->se_rssi < STA_RSSI_MIN)
fail |= MATCH_RSSI;
#ifdef IEEE80211_DEBUG
if (ieee80211_msg(ic, debug)) {
printf(" %c %s",
fail & MATCH_FAILS ? '=' :
fail & MATCH_NOTSEEN ? '^' :
fail ? '-' : '+', ether_sprintf(se->se_macaddr));
printf(" %s%c", ether_sprintf(se->se_bssid),
fail & MATCH_BSSID ? '!' : ' ');
printf(" %3d%c", ieee80211_chan2ieee(ic, se->se_chan),
fail & MATCH_CHANNEL ? '!' : ' ');
printf(" %+4d%c", se->se_rssi, fail & MATCH_RSSI ? '!' : ' ');
printf(" %2dM%c", (rate & IEEE80211_RATE_VAL) / 2,
fail & MATCH_RATE ? '!' : ' ');
printf(" %4s%c",
(se->se_capinfo & IEEE80211_CAPINFO_ESS) ? "ess" :
(se->se_capinfo & IEEE80211_CAPINFO_IBSS) ? "ibss" :
"????",
fail & MATCH_CAPINFO ? '!' : ' ');
printf(" %3s%c ",
(se->se_capinfo & IEEE80211_CAPINFO_PRIVACY) ?
"wep" : "no",
fail & MATCH_PRIVACY ? '!' : ' ');
ieee80211_print_essid(se->se_ssid+2, se->se_ssid[1]);
printf("%s\n", fail & MATCH_SSID ? "!" : "");
}
#endif
return fail;
}
static void
sta_update_notseen(struct sta_table *st)
{
struct sta_entry *se;
mtx_lock(&st->st_lock);
TAILQ_FOREACH(se, &st->st_entry, se_list) {
/*
* If seen the reset and don't bump the count;
* otherwise bump the ``not seen'' count. Note
* that this insures 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++;
}
mtx_unlock(&st->st_lock);
}
static void
sta_dec_fails(struct sta_table *st)
{
struct sta_entry *se;
mtx_lock(&st->st_lock);
TAILQ_FOREACH(se, &st->st_entry, se_list)
if (se->se_fails)
se->se_fails--;
mtx_unlock(&st->st_lock);
}
static struct sta_entry *
select_bss(struct ieee80211_scan_state *ss, struct ieee80211com *ic, int debug)
{
struct sta_table *st = ss->ss_priv;
struct sta_entry *se, *selbs = NULL;
IEEE80211_DPRINTF(ic, debug, " %s\n",
"macaddr bssid chan rssi rate flag wep essid");
mtx_lock(&st->st_lock);
TAILQ_FOREACH(se, &st->st_entry, se_list) {
if (match_bss(ic, ss, se, debug) == 0) {
if (selbs == NULL)
selbs = se;
else if (sta_compare(se, selbs) > 0)
selbs = se;
}
}
mtx_unlock(&st->st_lock);
return selbs;
}
/*
* Pick an ap or ibss network to join or find a channel
* to use to start an ibss network.
*/
static int
sta_pick_bss(struct ieee80211_scan_state *ss, struct ieee80211com *ic)
{
struct sta_table *st = ss->ss_priv;
struct sta_entry *selbs;
KASSERT(ic->ic_opmode == IEEE80211_M_STA,
("wrong mode %u", ic->ic_opmode));
if (st->st_newscan) {
sta_update_notseen(st);
st->st_newscan = 0;
}
if (ss->ss_flags & IEEE80211_SCAN_NOPICK) {
/*
* Manual/background scan, don't select+join the
* bss, just return. The scanning framework will
* handle notification that this has completed.
*/
ss->ss_flags &= ~IEEE80211_SCAN_NOPICK;
return 1;
}
/*
* Automatic sequencing; look for a candidate and
* if found join the network.
*/
/* NB: unlocked read should be ok */
if (TAILQ_FIRST(&st->st_entry) == NULL) {
IEEE80211_DPRINTF(ic, IEEE80211_MSG_SCAN,
"%s: no scan candidate\n", __func__);
notfound:
/*
* If nothing suitable was found decrement
* the failure counts so entries will be
* reconsidered the next time around. We
* really want to do this only for sta's
* where we've previously had some success.
*/
sta_dec_fails(st);
st->st_newscan = 1;
return 0; /* restart scan */
}
selbs = select_bss(ss, ic, IEEE80211_MSG_SCAN);
if (selbs == NULL || !ieee80211_sta_join(ic, &selbs->base))
goto notfound;
return 1; /* terminate scan */
}
/*
* Lookup an entry in the scan cache. We assume we're
* called from the bottom half or such that we don't need
* to block the bottom half so that it's safe to return
* a reference to an entry w/o holding the lock on the table.
*/
static struct sta_entry *
sta_lookup(struct sta_table *st, const uint8_t macaddr[IEEE80211_ADDR_LEN])
{
struct sta_entry *se;
int hash = STA_HASH(macaddr);
mtx_lock(&st->st_lock);
LIST_FOREACH(se, &st->st_hash[hash], se_hash)
if (IEEE80211_ADDR_EQ(se->base.se_macaddr, macaddr))
break;
mtx_unlock(&st->st_lock);
return se; /* NB: unlocked */
}
static void
sta_roam_check(struct ieee80211_scan_state *ss, struct ieee80211com *ic)
{
struct ieee80211_node *ni = ic->ic_bss;
struct sta_table *st = ss->ss_priv;
struct sta_entry *se, *selbs;
uint8_t roamRate, curRate;
int8_t roamRssi, curRssi;
se = sta_lookup(st, ni->ni_macaddr);
if (se == NULL) {
/* XXX something is wrong */
return;
}
/* XXX do we need 11g too? */
if (IEEE80211_IS_CHAN_ANYG(ic->ic_bsschan)) {
roamRate = ic->ic_roam.rate11b;
roamRssi = ic->ic_roam.rssi11b;
} else if (IEEE80211_IS_CHAN_B(ic->ic_bsschan)) {
roamRate = ic->ic_roam.rate11bOnly;
roamRssi = ic->ic_roam.rssi11bOnly;
} else {
roamRate = ic->ic_roam.rate11a;
roamRssi = ic->ic_roam.rssi11a;
}
/* NB: the most up to date rssi is in the node, not the scan cache */
curRssi = ic->ic_node_getrssi(ni);
if (ic->ic_fixed_rate == IEEE80211_FIXED_RATE_NONE) {
curRate = ni->ni_rates.rs_rates[ni->ni_txrate] & IEEE80211_RATE_VAL;
IEEE80211_DPRINTF(ic, IEEE80211_MSG_ROAM,
"%s: currssi %d currate %u roamrssi %d roamrate %u\n",
__func__, curRssi, curRate, roamRssi, roamRate);
} else {
curRate = roamRate; /* NB: insure compare below fails */
IEEE80211_DPRINTF(ic, IEEE80211_MSG_ROAM,
"%s: currssi %d roamrssi %d\n", __func__, curRssi, roamRssi);
}
/*
* Check if a new ap should be used and switch.
* XXX deauth current ap
*/
if (curRate < roamRate || curRssi < roamRssi) {
if (time_after(ticks, ic->ic_lastscan + ic->ic_scanvalid)) {
/*
* Scan cache contents are too old; force a scan now
* if possible so we have current state to make a
* decision with. We don't kick off a bg scan if
* we're using dynamic turbo and boosted or if the
* channel is busy.
* XXX force immediate switch on scan complete
*/
if (!IEEE80211_IS_CHAN_DTURBO(ic->ic_curchan) &&
time_after(ticks, ic->ic_lastdata + ic->ic_bgscanidle))
ieee80211_bg_scan(ic);
return;
}
se->base.se_rssi = curRssi;
selbs = select_bss(ss, ic, IEEE80211_MSG_ROAM);
if (selbs != NULL && selbs != se) {
IEEE80211_DPRINTF(ic,
IEEE80211_MSG_ROAM | IEEE80211_MSG_DEBUG,
"%s: ROAM: curRate %u, roamRate %u, "
"curRssi %d, roamRssi %d\n", __func__,
curRate, roamRate, curRssi, roamRssi);
ieee80211_sta_join(ic, &selbs->base);
}
}
}
/*
* Age entries in the scan cache.
* XXX also do roaming since it's convenient
*/
static void
sta_age(struct ieee80211_scan_state *ss)
{
struct ieee80211com *ic = ss->ss_ic;
struct sta_table *st = ss->ss_priv;
struct sta_entry *se, *next;
mtx_lock(&st->st_lock);
TAILQ_FOREACH_SAFE(se, &st->st_entry, se_list, next) {
if (se->se_notseen > STA_PURGE_SCANS) {
TAILQ_REMOVE(&st->st_entry, se, se_list);
LIST_REMOVE(se, se_hash);
FREE(se, M_80211_SCAN);
}
}
mtx_unlock(&st->st_lock);
/*
* If rate control is enabled check periodically to see if
* we should roam from our current connection to one that
* might be better. This only applies when we're operating
* in sta mode and automatic roaming is set.
* XXX defer if busy
* XXX repeater station
* XXX do when !bgscan?
*/
KASSERT(ic->ic_opmode == IEEE80211_M_STA,
("wrong mode %u", ic->ic_opmode));
if (ic->ic_roaming == IEEE80211_ROAMING_AUTO &&
(ic->ic_flags & IEEE80211_F_BGSCAN) &&
ic->ic_state >= IEEE80211_S_RUN)
/* XXX vap is implicit */
sta_roam_check(ss, ic);
}
/*
* Iterate over the entries in the scan cache, invoking
* the callback function on each one.
*/
static void
sta_iterate(struct ieee80211_scan_state *ss,
ieee80211_scan_iter_func *f, void *arg)
{
struct sta_table *st = ss->ss_priv;
struct sta_entry *se;
u_int gen;
mtx_lock(&st->st_scanlock);
gen = st->st_scangen++;
restart:
mtx_lock(&st->st_lock);
TAILQ_FOREACH(se, &st->st_entry, se_list) {
if (se->se_scangen != gen) {
se->se_scangen = gen;
/* update public state */
se->base.se_age = ticks - se->se_lastupdate;
mtx_unlock(&st->st_lock);
(*f)(arg, &se->base);
goto restart;
}
}
mtx_unlock(&st->st_lock);
mtx_unlock(&st->st_scanlock);
}
static void
sta_assoc_fail(struct ieee80211_scan_state *ss,
const uint8_t macaddr[IEEE80211_ADDR_LEN], int reason)
{
struct sta_table *st = ss->ss_priv;
struct sta_entry *se;
se = sta_lookup(st, macaddr);
if (se != NULL) {
se->se_fails++;
se->se_lastfail = ticks;
IEEE80211_NOTE_MAC(ss->ss_ic, IEEE80211_MSG_SCAN,
macaddr, "%s: reason %u fails %u",
__func__, reason, se->se_fails);
}
}
static void
sta_assoc_success(struct ieee80211_scan_state *ss,
const uint8_t macaddr[IEEE80211_ADDR_LEN])
{
struct sta_table *st = ss->ss_priv;
struct sta_entry *se;
se = sta_lookup(st, macaddr);
if (se != NULL) {
#if 0
se->se_fails = 0;
IEEE80211_NOTE_MAC(ss->ss_ic, IEEE80211_MSG_SCAN,
macaddr, "%s: fails %u",
__func__, se->se_fails);
#endif
se->se_lastassoc = ticks;
}
}
static const struct ieee80211_scanner sta_default = {
.scan_name = "default",
.scan_attach = sta_attach,
.scan_detach = sta_detach,
.scan_start = sta_start,
.scan_restart = sta_restart,
.scan_cancel = sta_cancel,
.scan_end = sta_pick_bss,
.scan_flush = sta_flush,
.scan_add = sta_add,
.scan_age = sta_age,
.scan_iterate = sta_iterate,
.scan_assoc_fail = sta_assoc_fail,
.scan_assoc_success = sta_assoc_success,
};
/*
* Adhoc mode-specific support.
*/
static const uint16_t adhocWorld[] = /* 36, 40, 44, 48 */
{ 5180, 5200, 5220, 5240 };
static const uint16_t adhocFcc3[] = /* 36, 40, 44, 48 145, 149, 153, 157, 161, 165 */
{ 5180, 5200, 5220, 5240, 5725, 5745, 5765, 5785, 5805, 5825 };
static const uint16_t adhocMkk[] = /* 34, 38, 42, 46 */
{ 5170, 5190, 5210, 5230 };
static const uint16_t adhoc11b[] = /* 10, 11 */
{ 2457, 2462 };
static const struct scanlist adhocScanTable[] = {
{ IEEE80211_MODE_11B, X(adhoc11b) },
{ IEEE80211_MODE_11A, X(adhocWorld) },
{ IEEE80211_MODE_11A, X(adhocFcc3) },
{ IEEE80211_MODE_11B, X(adhocMkk) },
{ .list = NULL }
};
#undef X
/*
* Start an adhoc-mode scan by populating the channel list.
*/
static int
adhoc_start(struct ieee80211_scan_state *ss, struct ieee80211com *ic)
{
#define N(a) (sizeof(a)/sizeof(a[0]))
struct sta_table *st = ss->ss_priv;
const struct scanlist *scan;
enum ieee80211_phymode mode;
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 (scan = adhocScanTable; scan->list != NULL; scan++) {
mode = scan->mode;
if (ic->ic_des_mode != IEEE80211_MODE_AUTO) {
/*
* If a desired mode was specified, scan only
* channels that satisfy that constraint.
*/
if (ic->ic_des_mode != 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 (ic->ic_des_mode != IEEE80211_MODE_11G ||
mode != IEEE80211_MODE_11B)
continue;
mode = IEEE80211_MODE_11G; /* upgrade */
}
} else {
/*
* This lets add_channels upgrade an 11b channel
* to 11g if available.
*/
if (mode == IEEE80211_MODE_11B)
mode = IEEE80211_MODE_AUTO;
}
#ifdef IEEE80211_F_XR
/* XR does not operate on turbo channels */
if ((ic->ic_flags & IEEE80211_F_XR) &&
(mode == IEEE80211_MODE_TURBO_A ||
mode == IEEE80211_MODE_TURBO_G))
continue;
#endif
/*
* Add the list of the channels; any that are not
* in the master channel list will be discarded.
*/
add_channels(ic, ss, mode, scan->list, scan->count);
}
ss->ss_next = 0;
/* XXX tunables */
ss->ss_mindwell = msecs_to_ticks(200); /* 200ms */
ss->ss_maxdwell = msecs_to_ticks(200); /* 200ms */
#ifdef IEEE80211_DEBUG
if (ieee80211_msg_scan(ic)) {
if_printf(ic->ic_ifp, "scan set ");
ieee80211_scan_dump_channels(ss);
printf(" dwell min %ld max %ld\n",
ss->ss_mindwell, ss->ss_maxdwell);
}
#endif /* IEEE80211_DEBUG */
st->st_newscan = 1;
return 0;
#undef N
}
/*
* Select a channel to start an adhoc network on.
* The channel list was populated with appropriate
* channels so select one that looks least occupied.
* XXX need regulatory domain constraints
*/
static struct ieee80211_channel *
adhoc_pick_channel(struct ieee80211_scan_state *ss)
{
struct sta_table *st = ss->ss_priv;
struct sta_entry *se;
struct ieee80211_channel *c, *bestchan;
int i, bestrssi, maxrssi;
bestchan = NULL;
bestrssi = -1;
mtx_lock(&st->st_lock);
for (i = 0; i < ss->ss_last; i++) {
c = ss->ss_chans[i];
maxrssi = 0;
TAILQ_FOREACH(se, &st->st_entry, se_list) {
if (se->base.se_chan != c)
continue;
if (se->base.se_rssi > maxrssi)
maxrssi = se->base.se_rssi;
}
if (bestchan == NULL || maxrssi < bestrssi)
bestchan = c;
}
mtx_unlock(&st->st_lock);
return bestchan;
}
/*
* Pick an ibss network to join or find a channel
* to use to start an ibss network.
*/
static int
adhoc_pick_bss(struct ieee80211_scan_state *ss, struct ieee80211com *ic)
{
struct sta_table *st = ss->ss_priv;
struct sta_entry *selbs;
struct ieee80211_channel *chan;
KASSERT(ic->ic_opmode == IEEE80211_M_IBSS ||
ic->ic_opmode == IEEE80211_M_AHDEMO,
("wrong opmode %u", ic->ic_opmode));
if (st->st_newscan) {
sta_update_notseen(st);
st->st_newscan = 0;
}
if (ss->ss_flags & IEEE80211_SCAN_NOPICK) {
/*
* Manual/background scan, don't select+join the
* bss, just return. The scanning framework will
* handle notification that this has completed.
*/
ss->ss_flags &= ~IEEE80211_SCAN_NOPICK;
return 1;
}
/*
* Automatic sequencing; look for a candidate and
* if found join the network.
*/
/* NB: unlocked read should be ok */
if (TAILQ_FIRST(&st->st_entry) == NULL) {
IEEE80211_DPRINTF(ic, IEEE80211_MSG_SCAN,
"%s: no scan candidate\n", __func__);
notfound:
if (ic->ic_des_nssid) {
/*
* No existing adhoc network to join and we have
* an ssid; start one up. If no channel was
* specified, try to select a channel.
*/
if (ic->ic_des_chan == IEEE80211_CHAN_ANYC)
chan = ieee80211_ht_adjust_channel(ic,
adhoc_pick_channel(ss), ic->ic_flags_ext);
else
chan = ic->ic_des_chan;
if (chan != NULL) {
ieee80211_create_ibss(ic, chan);
return 1;
}
}
/*
* If nothing suitable was found decrement
* the failure counts so entries will be
* reconsidered the next time around. We
* really want to do this only for sta's
* where we've previously had some success.
*/
sta_dec_fails(st);
st->st_newscan = 1;
return 0; /* restart scan */
}
selbs = select_bss(ss, ic, IEEE80211_MSG_SCAN);
if (selbs == NULL || !ieee80211_sta_join(ic, &selbs->base))
goto notfound;
return 1; /* terminate scan */
}
/*
* Age entries in the scan cache.
*/
static void
adhoc_age(struct ieee80211_scan_state *ss)
{
struct sta_table *st = ss->ss_priv;
struct sta_entry *se, *next;
mtx_lock(&st->st_lock);
TAILQ_FOREACH_SAFE(se, &st->st_entry, se_list, next) {
if (se->se_notseen > STA_PURGE_SCANS) {
TAILQ_REMOVE(&st->st_entry, se, se_list);
LIST_REMOVE(se, se_hash);
FREE(se, M_80211_SCAN);
}
}
mtx_unlock(&st->st_lock);
}
static const struct ieee80211_scanner adhoc_default = {
.scan_name = "default",
.scan_attach = sta_attach,
.scan_detach = sta_detach,
.scan_start = adhoc_start,
.scan_restart = sta_restart,
.scan_cancel = sta_cancel,
.scan_end = adhoc_pick_bss,
.scan_flush = sta_flush,
.scan_add = sta_add,
.scan_age = adhoc_age,
.scan_iterate = sta_iterate,
.scan_assoc_fail = sta_assoc_fail,
.scan_assoc_success = sta_assoc_success,
};
/*
* Module glue.
*/
static int
wlan_modevent(module_t mod, int type, void *unused)
{
switch (type) {
case MOD_LOAD:
ieee80211_scanner_register(IEEE80211_M_STA, &sta_default);
ieee80211_scanner_register(IEEE80211_M_IBSS, &adhoc_default);
ieee80211_scanner_register(IEEE80211_M_AHDEMO, &adhoc_default);
return 0;
case MOD_UNLOAD:
case MOD_QUIESCE:
if (nrefs) {
printf("wlan_scan_sta: still in use (%u dynamic refs)\n",
nrefs);
return EBUSY;
}
if (type == MOD_UNLOAD) {
ieee80211_scanner_unregister_all(&sta_default);
ieee80211_scanner_unregister_all(&adhoc_default);
}
return 0;
}
return EINVAL;
}
static moduledata_t wlan_mod = {
"wlan_scan_sta",
wlan_modevent,
0
};
DECLARE_MODULE(wlan_scan_sta, wlan_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST);
MODULE_VERSION(wlan_scan_sta, 1);
MODULE_DEPEND(wlan_scan_sta, wlan, 1, 1, 1);