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freebsd-dev/sys/net80211/ieee80211_scan_sta.c
Sam Leffler e2126dec84 convert MALLOC/FREE to malloc/free
2008-12-18 23:00:09 +00:00

1694 lines
47 KiB
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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)
#define MAX_IEEE_CHAN 256 /* max acceptable IEEE chan # */
CTASSERT(MAX_IEEE_CHAN >= 256);
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[MAX_IEEE_CHAN];
};
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;
st = (struct sta_table *) malloc(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;
se = (struct sta_entry *) malloc(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;
KASSERT(sizeof(sp->bchan) == 1, ("bchan size"));
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;
KASSERT(sizeof(chan->ic_ieee) == 1, ("ic_chan size"));
/* 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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