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freebsd-dev/sys/net80211/ieee80211_scan_sta.c
Sam Leffler 8f4addc0a8 Fix joining an 11b BSS: scanning is normally done using 11g channels 
(unless explicitly locked to mode 11b) so when we join the bss the
channel attached to the scan cache entry may need to be demoted.

o demote to 11b if the ap is advertising 11b rates
o skip the ap if it's 11b but we're locked to 11g (could consider this
  advisory but for now treat it as mandatory)
o handle an odd edge case, if there is a fixed transmit rate for 11g
  then the rate check against the 11b ap will fail, try to demote to
  11b and retry the rate check

Reviewed by:	sephe, thompsa
2008-10-26 21:56:27 +00:00

1689 lines
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/*-
* Copyright (c) 2002-2008 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 "opt_wlan.h"
#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 <net80211/ieee80211_input.h>
#include <net80211/ieee80211_regdomain.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 */
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;
#define STA_DEMOTE11B 0x01 /* match w/ demoted 11b chan */
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# */
u_int se_countrygen; /* gen# of last cc notify */
};
#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_scaniter */
u_int st_scaniter; /* gen# for iterator */
u_int st_scangen; /* scan generation # */
int st_newscan;
/* ap-related state */
int st_maxrssi[IEEE80211_CHAN_MAX];
};
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 0x0001 /* channel mismatch */
#define MATCH_CAPINFO 0x0002 /* capabilities mismatch, e.g. no ess */
#define MATCH_PRIVACY 0x0004 /* privacy mismatch */
#define MATCH_RATE 0x0008 /* rate set mismatch */
#define MATCH_SSID 0x0010 /* ssid mismatch */
#define MATCH_BSSID 0x0020 /* bssid mismatch */
#define MATCH_FAILS 0x0040 /* too many failed auth attempts */
#define MATCH_NOTSEEN 0x0080 /* not seen in recent scans */
#define MATCH_RSSI 0x0100 /* rssi deemed too low to use */
#define MATCH_CC 0x0200 /* country code mismatch */
static int match_bss(struct ieee80211vap *,
const struct ieee80211_scan_state *, struct sta_entry *, int);
static void adhoc_age(struct ieee80211_scan_state *);
static __inline int
isocmp(const uint8_t cc1[], const uint8_t cc2[])
{
return (cc1[0] == cc2[0] && cc1[1] == cc2[1]);
}
/* 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);
ieee80211_ies_cleanup(&se->base.se_ies);
FREE(se, M_80211_SCAN);
}
memset(st->st_maxrssi, 0, sizeof(st->st_maxrssi));
}
/*
* 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 ieee80211vap *vap = ss->ss_vap;
struct ieee80211com *ic = vap->iv_ic;
struct sta_entry *se;
struct ieee80211_scan_entry *ise;
int hash;
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_scaniter-1;
se->se_avgrssi = IEEE80211_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] <= 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);
if ((sp->status & IEEE80211_BPARSE_OFFCHAN) == 0) {
/*
* 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.
*/
IEEE80211_RSSI_LPF(se->se_avgrssi, rssi);
ise->se_rssi = IEEE80211_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
* association on the wrong channel.
*/
if (sp->status & IEEE80211_BPARSE_OFFCHAN) {
struct ieee80211_channel *c;
/*
* Off-channel, locate the home/bss channel for the sta
* using the value broadcast in the DSPARMS ie. We know
* sp->chan has this value because it's used to calculate
* IEEE80211_BPARSE_OFFCHAN.
*/
c = ieee80211_find_channel_byieee(ic, sp->chan,
ic->ic_curchan->ic_flags);
if (c != NULL) {
ise->se_chan = c;
} else if (ise->se_chan == NULL) {
/* should not happen, pick something */
ise->se_chan = ic->ic_curchan;
}
} else
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;
}
if (sp->country != NULL) {
const struct ieee80211_country_ie *cie =
(const struct ieee80211_country_ie *) sp->country;
/*
* If 11d is enabled and we're attempting to join a bss
* that advertises it's country code then compare our
* current settings to what we fetched from the country ie.
* If our country code is unspecified or different then
* dispatch an event to user space that identifies the
* country code so our regdomain config can be changed.
*/
/* XXX only for STA mode? */
if ((IEEE80211_IS_CHAN_11D(ise->se_chan) ||
(vap->iv_flags_ext & IEEE80211_FEXT_DOTD)) &&
(ic->ic_regdomain.country == CTRY_DEFAULT ||
!isocmp(cie->cc, ic->ic_regdomain.isocc))) {
/* only issue one notify event per scan */
if (se->se_countrygen != st->st_scangen) {
ieee80211_notify_country(vap, ise->se_bssid,
cie->cc);
se->se_countrygen = st->st_scangen;
}
}
ise->se_cc[0] = cie->cc[0];
ise->se_cc[1] = cie->cc[1];
}
/* NB: no need to setup ie ptrs; they are not (currently) used */
(void) ieee80211_ies_init(&ise->se_ies, sp->ies, sp->ies_len);
/* 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(vap, 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;
if (rssi > st->st_maxrssi[sp->bchan])
st->st_maxrssi[sp->bchan] = rssi;
mtx_unlock(&st->st_lock);
/*
* If looking for a quick choice and nothing's
* been found check here.
*/
if (PICK1ST(ss) && match_bss(vap, 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 ieee80211vap *vap, const struct ieee80211_channel *c)
{
return (isclr(vap->iv_ic->ic_chan_active, c->ic_ieee) ||
(vap->iv_des_chan != IEEE80211_CHAN_ANYC &&
c->ic_freq != vap->iv_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 ieee80211vap *vap,
struct ieee80211_scan_state *ss,
enum ieee80211_phymode mode, const uint16_t freq[], int nfreq)
{
#define N(a) (sizeof(a) / sizeof(a[0]))
struct ieee80211com *ic = vap->iv_ic;
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(vap, c))
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;
}
ss->ss_chans[ss->ss_last++] = c;
}
#undef N
}
struct scanlist {
uint16_t mode;
uint16_t count;
const uint16_t *list;
};
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;
}
static void
sweepchannels(struct ieee80211_scan_state *ss, struct ieee80211vap *vap,
const struct scanlist table[])
{
struct ieee80211com *ic = vap->iv_ic;
struct ieee80211_channel *c;
int i;
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 (vap->iv_des_mode != IEEE80211_MODE_AUTO &&
vap->iv_des_mode != ieee80211_chan2mode(c))
continue;
/*
* Skip channels excluded by user request.
*/
if (isexcluded(vap, 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(table, c))
continue;
/* Add channel to scanning list. */
ss->ss_chans[ss->ss_last++] = c;
}
}
static void
makescanlist(struct ieee80211_scan_state *ss, struct ieee80211vap *vap,
const struct scanlist table[])
{
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 = table; scan->list != NULL; scan++) {
mode = scan->mode;
if (vap->iv_des_mode != IEEE80211_MODE_AUTO) {
/*
* If a desired mode was specified, scan only
* channels that satisfy that constraint.
*/
if (vap->iv_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 (vap->iv_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 ((vap->iv_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(vap, ss, mode, scan->list, scan->count);
}
/*
* Add the channels from the ic that are not present
* in the table.
*/
sweepchannels(ss, vap, table);
}
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 */
#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 }
};
/*
* Start a station-mode scan by populating the channel list.
*/
static int
sta_start(struct ieee80211_scan_state *ss, struct ieee80211vap *vap)
{
struct sta_table *st = ss->ss_priv;
makescanlist(ss, vap, staScanTable);
if (ss->ss_mindwell == 0)
ss->ss_mindwell = msecs_to_ticks(20); /* 20ms */
if (ss->ss_maxdwell == 0)
ss->ss_maxdwell = msecs_to_ticks(200); /* 200ms */
st->st_scangen++;
st->st_newscan = 1;
return 0;
}
/*
* Restart a scan, typically a bg scan but can
* also be a fg scan that came up empty.
*/
static int
sta_restart(struct ieee80211_scan_state *ss, struct ieee80211vap *vap)
{
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 ieee80211vap *vap)
{
return 0;
}
/* unalligned little endian access */
#define LE_READ_2(p) \
((uint16_t) \
((((const uint8_t *)(p))[0] ) | \
(((const uint8_t *)(p))[1] << 8)))
/*
* Demote any supplied 11g channel to 11b. There should
* always be an 11b channel but we check anyway...
*/
static struct ieee80211_channel *
demote11b(struct ieee80211vap *vap, struct ieee80211_channel *chan)
{
struct ieee80211_channel *c;
if (IEEE80211_IS_CHAN_ANYG(chan) &&
vap->iv_des_mode == IEEE80211_MODE_AUTO) {
c = ieee80211_find_channel(vap->iv_ic, chan->ic_freq,
(chan->ic_flags &~ (IEEE80211_CHAN_PUREG | IEEE80211_CHAN_G)) |
IEEE80211_CHAN_B);
if (c != NULL)
chan = c;
}
return chan;
}
static int
maxrate(const struct ieee80211_scan_entry *se)
{
const struct ieee80211_ie_htcap *htcap =
(const struct ieee80211_ie_htcap *) se->se_ies.htcap_ie;
int rmax, r, i;
uint16_t caps;
rmax = 0;
if (htcap != NULL) {
/*
* HT station; inspect supported MCS and then adjust
* rate by channel width. Could also include short GI
* in this if we want to be extra accurate.
*/
/* XXX assumes MCS15 is max */
for (i = 15; i >= 0 && isclr(htcap->hc_mcsset, i); i--)
;
if (i >= 0) {
caps = LE_READ_2(&htcap->hc_cap);
/* XXX short/long GI */
if (caps & IEEE80211_HTCAP_CHWIDTH40)
rmax = ieee80211_htrates[i].ht40_rate_400ns;
else
rmax = ieee80211_htrates[i].ht40_rate_800ns;
}
}
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)
int 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 */
PREFER(IEEE80211_IS_CHAN_5GHZ(a->base.se_chan),
IEEE80211_IS_CHAN_5GHZ(b->base.se_chan), 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.
* XXX inspect MCS for HT
*/
static int
check_rate(struct ieee80211vap *vap, const struct ieee80211_channel *chan,
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, ucastrate;
const uint8_t *rs;
okrate = badrate = 0;
srs = ieee80211_get_suprates(vap->iv_ic, chan);
nrs = se->se_rates[1];
rs = se->se_rates+2;
/* XXX MCS */
ucastrate = vap->iv_txparms[ieee80211_chan2mode(chan)].ucastrate;
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 == ucastrate)
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 || ucastrate != 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 ieee80211vap *vap,
const struct ieee80211_scan_state *ss, struct sta_entry *se0,
int debug)
{
struct ieee80211com *ic = vap->iv_ic;
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 (vap->iv_des_mode != IEEE80211_MODE_AUTO &&
(se->se_chan->ic_flags & IEEE80211_CHAN_ALLTURBO) !=
chanflags[vap->iv_des_mode])
fail |= MATCH_CHANNEL;
if (vap->iv_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 11d is enabled and we're attempting to join a bss
* that advertises it's country code then compare our
* current settings to what we fetched from the country ie.
* If our country code is unspecified or different then do
* not attempt to join the bss. We should have already
* dispatched an event to user space that identifies the
* new country code so our regdomain config should match.
*/
if ((IEEE80211_IS_CHAN_11D(se->se_chan) ||
(vap->iv_flags_ext & IEEE80211_FEXT_DOTD)) &&
se->se_cc[0] != 0 &&
(ic->ic_regdomain.country == CTRY_DEFAULT ||
!isocmp(se->se_cc, ic->ic_regdomain.isocc)))
fail |= MATCH_CC;
}
if (vap->iv_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;
}
se0->se_flags &= ~STA_DEMOTE11B;
rate = check_rate(vap, se->se_chan, se);
if (rate & IEEE80211_RATE_BASIC) {
fail |= MATCH_RATE;
/*
* An 11b-only ap will give a rate mismatch if there is an
* OFDM fixed tx rate for 11g. Try downgrading the channel
* in the scan list to 11b and retry the rate check.
*/
if (IEEE80211_IS_CHAN_ANYG(se->se_chan)) {
rate = check_rate(vap, demote11b(vap, se->se_chan), se);
if ((rate & IEEE80211_RATE_BASIC) == 0) {
fail &= ~MATCH_RATE;
se0->se_flags |= STA_DEMOTE11B;
}
}
} else if (rate < 2*24) {
/*
* This is an 11b-only ap. Check the desired mode in
* case that needs to be honored (mode 11g filters out
* 11b-only ap's). Otherwise force any 11g channel used
* in scanning to be demoted.
*
* NB: we cheat a bit here by looking at the max rate;
* we could/should check the rates.
*/
if (!(vap->iv_des_mode == IEEE80211_MODE_AUTO ||
vap->iv_des_mode == IEEE80211_MODE_11B))
fail |= MATCH_RATE;
else
se0->se_flags |= STA_DEMOTE11B;
}
if (ss->ss_nssid != 0 &&
!match_ssid(se->se_ssid, ss->ss_nssid, ss->ss_ssid))
fail |= MATCH_SSID;
if ((vap->iv_flags & IEEE80211_F_DESBSSID) &&
!IEEE80211_ADDR_EQ(vap->iv_des_bssid, se->se_bssid))
fail |= MATCH_BSSID;
if (se0->se_fails >= STA_FAILS_MAX)
fail |= MATCH_FAILS;
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(vap, debug)) {
printf(" %c %s",
fail & MATCH_FAILS ? '=' :
fail & MATCH_NOTSEEN ? '^' :
fail & MATCH_CC ? '$' :
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 ieee80211vap *vap, int debug)
{
struct sta_table *st = ss->ss_priv;
struct sta_entry *se, *selbs = NULL;
IEEE80211_DPRINTF(vap, debug, " %s\n",
"macaddr bssid chan rssi rate flag wep essid");
mtx_lock(&st->st_lock);
TAILQ_FOREACH(se, &st->st_entry, se_list) {
ieee80211_ies_expand(&se->base.se_ies);
if (match_bss(vap, 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 ieee80211vap *vap)
{
struct sta_table *st = ss->ss_priv;
struct sta_entry *selbs;
struct ieee80211_channel *chan;
KASSERT(vap->iv_opmode == IEEE80211_M_STA,
("wrong mode %u", vap->iv_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(vap, IEEE80211_MSG_SCAN,
"%s: no scan candidate\n", __func__);
if (ss->ss_flags & IEEE80211_SCAN_NOJOIN)
return 0;
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, vap, IEEE80211_MSG_SCAN);
if (ss->ss_flags & IEEE80211_SCAN_NOJOIN)
return (selbs != NULL);
if (selbs == NULL)
goto notfound;
chan = selbs->base.se_chan;
if (selbs->se_flags & STA_DEMOTE11B)
chan = demote11b(vap, chan);
if (!ieee80211_sta_join(vap, chan, &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 ieee80211vap *vap)
{
struct ieee80211com *ic = vap->iv_ic;
struct ieee80211_node *ni = vap->iv_bss;
struct sta_table *st = ss->ss_priv;
enum ieee80211_phymode mode;
struct sta_entry *se, *selbs;
uint8_t roamRate, curRate, ucastRate;
int8_t roamRssi, curRssi;
se = sta_lookup(st, ni->ni_macaddr);
if (se == NULL) {
/* XXX something is wrong */
return;
}
mode = ieee80211_chan2mode(ic->ic_bsschan);
roamRate = vap->iv_roamparms[mode].rate;
roamRssi = vap->iv_roamparms[mode].rssi;
ucastRate = vap->iv_txparms[mode].ucastrate;
/* NB: the most up to date rssi is in the node, not the scan cache */
curRssi = ic->ic_node_getrssi(ni);
if (ucastRate == IEEE80211_FIXED_RATE_NONE) {
curRate = ni->ni_txrate;
roamRate &= IEEE80211_RATE_VAL;
IEEE80211_DPRINTF(vap, 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(vap, 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 + vap->iv_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 + vap->iv_bgscanidle))
ieee80211_bg_scan(vap, 0);
return;
}
se->base.se_rssi = curRssi;
selbs = select_bss(ss, vap, IEEE80211_MSG_ROAM);
if (selbs != NULL && selbs != se) {
struct ieee80211_channel *chan;
IEEE80211_DPRINTF(vap,
IEEE80211_MSG_ROAM | IEEE80211_MSG_DEBUG,
"%s: ROAM: curRate %u, roamRate %u, "
"curRssi %d, roamRssi %d\n", __func__,
curRate, roamRate, curRssi, roamRssi);
chan = selbs->base.se_chan;
if (selbs->se_flags & STA_DEMOTE11B)
chan = demote11b(vap, chan);
(void) ieee80211_sta_join(vap, chan, &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 ieee80211vap *vap = ss->ss_vap;
adhoc_age(ss);
/*
* 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(vap->iv_opmode == IEEE80211_M_STA,
("wrong mode %u", vap->iv_opmode));
if (vap->iv_roaming == IEEE80211_ROAMING_AUTO &&
(vap->iv_ic->ic_flags & IEEE80211_F_BGSCAN) &&
vap->iv_state >= IEEE80211_S_RUN)
/* XXX vap is implicit */
sta_roam_check(ss, vap);
}
/*
* 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_scaniter++;
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_vap, 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_vap, 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 ieee80211vap *vap)
{
struct sta_table *st = ss->ss_priv;
makescanlist(ss, vap, adhocScanTable);
if (ss->ss_mindwell == 0)
ss->ss_mindwell = msecs_to_ticks(200); /* 200ms */
if (ss->ss_maxdwell == 0)
ss->ss_maxdwell = msecs_to_ticks(200); /* 200ms */
st->st_scangen++;
st->st_newscan = 1;
return 0;
}
/*
* Select a channel to start an adhoc network on.
* The channel list was populated with appropriate
* channels so select one that looks least occupied.
*/
static struct ieee80211_channel *
adhoc_pick_channel(struct ieee80211_scan_state *ss, int flags)
{
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];
/* never consider a channel with radar */
if (IEEE80211_IS_CHAN_RADAR(c))
continue;
/* skip channels disallowed by regulatory settings */
if (IEEE80211_IS_CHAN_NOADHOC(c))
continue;
/* check channel attributes for band compatibility */
if (flags != 0 && (c->ic_flags & flags) != flags)
continue;
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 ieee80211vap *vap)
{
struct sta_table *st = ss->ss_priv;
struct sta_entry *selbs;
struct ieee80211_channel *chan;
KASSERT(vap->iv_opmode == IEEE80211_M_IBSS ||
vap->iv_opmode == IEEE80211_M_AHDEMO,
("wrong opmode %u", vap->iv_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(vap, IEEE80211_MSG_SCAN,
"%s: no scan candidate\n", __func__);
if (ss->ss_flags & IEEE80211_SCAN_NOJOIN)
return 0;
notfound:
if (vap->iv_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 (vap->iv_des_chan == IEEE80211_CHAN_ANYC ||
IEEE80211_IS_CHAN_RADAR(vap->iv_des_chan)) {
struct ieee80211com *ic = vap->iv_ic;
chan = adhoc_pick_channel(ss, 0);
if (chan != NULL)
chan = ieee80211_ht_adjust_channel(ic,
chan, vap->iv_flags_ext);
} else
chan = vap->iv_des_chan;
if (chan != NULL) {
ieee80211_create_ibss(vap, 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, vap, IEEE80211_MSG_SCAN);
if (ss->ss_flags & IEEE80211_SCAN_NOJOIN)
return (selbs != NULL);
if (selbs == NULL)
goto notfound;
chan = selbs->base.se_chan;
if (selbs->se_flags & STA_DEMOTE11B)
chan = demote11b(vap, chan);
if (!ieee80211_sta_join(vap, chan, &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);
ieee80211_ies_cleanup(&se->base.se_ies);
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_pickchan = adhoc_pick_channel,
.scan_add = sta_add,
.scan_age = adhoc_age,
.scan_iterate = sta_iterate,
.scan_assoc_fail = sta_assoc_fail,
.scan_assoc_success = sta_assoc_success,
};
static void
ap_force_promisc(struct ieee80211com *ic)
{
struct ifnet *ifp = ic->ic_ifp;
IEEE80211_LOCK(ic);
/* set interface into promiscuous mode */
ifp->if_flags |= IFF_PROMISC;
ic->ic_update_promisc(ifp);
IEEE80211_UNLOCK(ic);
}
static void
ap_reset_promisc(struct ieee80211com *ic)
{
IEEE80211_LOCK(ic);
ieee80211_syncifflag_locked(ic, IFF_PROMISC);
IEEE80211_UNLOCK(ic);
}
static int
ap_start(struct ieee80211_scan_state *ss, struct ieee80211vap *vap)
{
struct sta_table *st = ss->ss_priv;
makescanlist(ss, vap, staScanTable);
if (ss->ss_mindwell == 0)
ss->ss_mindwell = msecs_to_ticks(200); /* 200ms */
if (ss->ss_maxdwell == 0)
ss->ss_maxdwell = msecs_to_ticks(200); /* 200ms */
st->st_scangen++;
st->st_newscan = 1;
ap_force_promisc(vap->iv_ic);
return 0;
}
/*
* Cancel an ongoing scan.
*/
static int
ap_cancel(struct ieee80211_scan_state *ss, struct ieee80211vap *vap)
{
ap_reset_promisc(vap->iv_ic);
return 0;
}
/*
* Pick a quiet channel to use for ap operation.
*/
static struct ieee80211_channel *
ap_pick_channel(struct ieee80211_scan_state *ss, int flags)
{
struct sta_table *st = ss->ss_priv;
struct ieee80211_channel *bestchan = NULL;
int i;
/* XXX select channel more intelligently, e.g. channel spread, power */
/* NB: use scan list order to preserve channel preference */
for (i = 0; i < ss->ss_last; i++) {
struct ieee80211_channel *chan = ss->ss_chans[i];
/*
* If the channel is unoccupied the max rssi
* should be zero; just take it. Otherwise
* track the channel with the lowest rssi and
* use that when all channels appear occupied.
*/
if (IEEE80211_IS_CHAN_RADAR(chan))
continue;
if (IEEE80211_IS_CHAN_NOHOSTAP(chan))
continue;
/* check channel attributes for band compatibility */
if (flags != 0 && (chan->ic_flags & flags) != flags)
continue;
/* XXX channel have interference */
if (st->st_maxrssi[chan->ic_ieee] == 0) {
/* XXX use other considerations */
return chan;
}
if (bestchan == NULL ||
st->st_maxrssi[chan->ic_ieee] < st->st_maxrssi[bestchan->ic_ieee])
bestchan = chan;
}
return bestchan;
}
/*
* Pick a quiet channel to use for ap operation.
*/
static int
ap_end(struct ieee80211_scan_state *ss, struct ieee80211vap *vap)
{
struct ieee80211com *ic = vap->iv_ic;
struct ieee80211_channel *bestchan;
KASSERT(vap->iv_opmode == IEEE80211_M_HOSTAP,
("wrong opmode %u", vap->iv_opmode));
bestchan = ap_pick_channel(ss, 0);
if (bestchan == NULL) {
/* no suitable channel, should not happen */
IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
"%s: no suitable channel! (should not happen)\n", __func__);
/* XXX print something? */
return 0; /* restart scan */
}
/*
* If this is a dynamic turbo channel, start with the unboosted one.
*/
if (IEEE80211_IS_CHAN_TURBO(bestchan)) {
bestchan = ieee80211_find_channel(ic, bestchan->ic_freq,
bestchan->ic_flags & ~IEEE80211_CHAN_TURBO);
if (bestchan == NULL) {
/* should never happen ?? */
return 0;
}
}
ap_reset_promisc(ic);
if (ss->ss_flags & (IEEE80211_SCAN_NOPICK | IEEE80211_SCAN_NOJOIN)) {
/*
* 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;
}
ieee80211_create_ibss(vap,
ieee80211_ht_adjust_channel(ic, bestchan, vap->iv_flags_ext));
return 1;
}
static const struct ieee80211_scanner ap_default = {
.scan_name = "default",
.scan_attach = sta_attach,
.scan_detach = sta_detach,
.scan_start = ap_start,
.scan_restart = sta_restart,
.scan_cancel = ap_cancel,
.scan_end = ap_end,
.scan_flush = sta_flush,
.scan_pickchan = ap_pick_channel,
.scan_add = sta_add,
.scan_age = adhoc_age,
.scan_iterate = sta_iterate,
.scan_assoc_success = sta_assoc_success,
.scan_assoc_fail = sta_assoc_fail,
};
/*
* Module glue.
*/
IEEE80211_SCANNER_MODULE(sta, 1);
IEEE80211_SCANNER_ALG(sta, IEEE80211_M_STA, sta_default);
IEEE80211_SCANNER_ALG(ibss, IEEE80211_M_IBSS, adhoc_default);
IEEE80211_SCANNER_ALG(ahdemo, IEEE80211_M_AHDEMO, adhoc_default);
IEEE80211_SCANNER_ALG(ap, IEEE80211_M_HOSTAP, ap_default);
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