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freebsd/sys/net80211/ieee80211_scan.c
Sam Leffler aa0fbc732a Simplify some contorted logic that wrongly left ISCAN_DISCARD set 
in certain cases causing the current ap to be lost from the scan cache.

Obtained from:	Atheros (original bug)
2008-05-28 23:15:24 +00:00

1234 lines
35 KiB
C
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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 scanning support.
*/
#include "opt_wlan.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/socket.h>
#include <net/if.h>
#include <net/if_media.h>
#include <net/ethernet.h>
#include <net80211/ieee80211_var.h>
#include <net/bpf.h>
struct scan_state {
struct ieee80211_scan_state base; /* public state */
u_int ss_iflags; /* flags used internally */
#define ISCAN_MINDWELL 0x0001 /* min dwell time reached */
#define ISCAN_DISCARD 0x0002 /* discard rx'd frames */
#define ISCAN_CANCEL 0x0004 /* cancel current scan */
#define ISCAN_START 0x0008 /* 1st time through next_scan */
unsigned long ss_chanmindwell; /* min dwell on curchan */
unsigned long ss_scanend; /* time scan must stop */
u_int ss_duration; /* duration for next scan */
struct callout ss_scan_timer; /* scan timer */
};
#define SCAN_PRIVATE(ss) ((struct scan_state *) ss)
/*
* Amount of time to go off-channel during a background
* scan. This value should be large enough to catch most
* ap's but short enough that we can return on-channel
* before our listen interval expires.
*
* XXX tunable
* XXX check against configured listen interval
*/
#define IEEE80211_SCAN_OFFCHANNEL msecs_to_ticks(150)
/*
* Roaming-related defaults. RSSI thresholds are as returned by the
* driver (dBm). Transmit rate thresholds are IEEE rate codes (i.e
* .5M units) or MCS.
*/
#define ROAM_RSSI_11A_DEFAULT 14 /* rssi threshold for 11a bss */
#define ROAM_RSSI_11B_DEFAULT 14 /* rssi threshold for 11b bss */
#define ROAM_RSSI_11BONLY_DEFAULT 14 /* rssi threshold for 11b-only bss */
#define ROAM_RATE_11A_DEFAULT 2*12 /* tx rate thresh for 11a bss */
#define ROAM_RATE_11B_DEFAULT 2*5 /* tx rate thresh for 11b bss */
#define ROAM_RATE_11BONLY_DEFAULT 2*1 /* tx rate thresh for 11b-only bss */
#define ROAM_MCS_11N_DEFAULT 1 /* tx MCS thresh for 11n bss*/
static void scan_restart_pwrsav(void *);
static void scan_curchan(struct ieee80211_scan_state *, unsigned long);
static void scan_mindwell(struct ieee80211_scan_state *);
static void scan_next(void *);
MALLOC_DEFINE(M_80211_SCAN, "80211scan", "802.11 scan state");
void
ieee80211_scan_attach(struct ieee80211com *ic)
{
struct scan_state *ss;
MALLOC(ss, struct scan_state *, sizeof(struct scan_state),
M_80211_SCAN, M_NOWAIT | M_ZERO);
if (ss == NULL) {
ic->ic_scan = NULL;
return;
}
callout_init_mtx(&ss->ss_scan_timer, IEEE80211_LOCK_OBJ(ic), 0);
ic->ic_scan = &ss->base;
ic->ic_scan_curchan = scan_curchan;
ic->ic_scan_mindwell = scan_mindwell;
}
void
ieee80211_scan_detach(struct ieee80211com *ic)
{
struct ieee80211_scan_state *ss = ic->ic_scan;
if (ss != NULL) {
callout_drain(&SCAN_PRIVATE(ss)->ss_scan_timer);
if (ss->ss_ops != NULL) {
ss->ss_ops->scan_detach(ss);
ss->ss_ops = NULL;
}
ic->ic_flags &= ~IEEE80211_F_SCAN;
ic->ic_scan = NULL;
FREE(SCAN_PRIVATE(ss), M_80211_SCAN);
}
}
static __inline void
setparams(struct ieee80211_roamparam *rp, int8_t rssi, uint8_t txrate)
{
rp->rssi = rssi;
rp->rate = txrate;
}
void
ieee80211_scan_vattach(struct ieee80211vap *vap)
{
struct ieee80211com *ic = vap->iv_ic;
vap->iv_bgscanidle = (IEEE80211_BGSCAN_IDLE_DEFAULT*1000)/hz;
vap->iv_bgscanintvl = IEEE80211_BGSCAN_INTVAL_DEFAULT*hz;
vap->iv_scanvalid = IEEE80211_SCAN_VALID_DEFAULT*hz;
vap->iv_roaming = IEEE80211_ROAMING_AUTO;
/* NB: only set supported modes so user apps can identify */
if (isset(ic->ic_modecaps, IEEE80211_MODE_11A))
setparams(&vap->iv_roamparms[IEEE80211_MODE_11A],
ROAM_RSSI_11A_DEFAULT, ROAM_RATE_11A_DEFAULT);
if (isset(ic->ic_modecaps, IEEE80211_MODE_11G))
setparams(&vap->iv_roamparms[IEEE80211_MODE_11G],
ROAM_RSSI_11B_DEFAULT, ROAM_RATE_11B_DEFAULT);
if (isset(ic->ic_modecaps, IEEE80211_MODE_11B))
setparams(&vap->iv_roamparms[IEEE80211_MODE_11B],
ROAM_RSSI_11BONLY_DEFAULT, ROAM_RATE_11BONLY_DEFAULT);
/* NB: default turbo controls to be the same as !turbo */
if (isset(ic->ic_modecaps, IEEE80211_MODE_TURBO_A))
vap->iv_roamparms[IEEE80211_MODE_TURBO_A] =
vap->iv_roamparms[IEEE80211_MODE_11A];
if (isset(ic->ic_modecaps, IEEE80211_MODE_TURBO_G))
vap->iv_roamparms[IEEE80211_MODE_TURBO_G] =
vap->iv_roamparms[IEEE80211_MODE_11G];
if (isset(ic->ic_modecaps, IEEE80211_MODE_STURBO_A))
vap->iv_roamparms[IEEE80211_MODE_STURBO_A] =
vap->iv_roamparms[IEEE80211_MODE_11A];
if (isset(ic->ic_modecaps, IEEE80211_MODE_11NA))
setparams(&vap->iv_roamparms[IEEE80211_MODE_11NA],
ROAM_RSSI_11A_DEFAULT, ROAM_MCS_11N_DEFAULT | 0x80);
if (isset(ic->ic_modecaps, IEEE80211_MODE_11NG))
setparams(&vap->iv_roamparms[IEEE80211_MODE_11NG],
ROAM_RSSI_11B_DEFAULT, ROAM_MCS_11N_DEFAULT | 0x80);
}
void
ieee80211_scan_vdetach(struct ieee80211vap *vap)
{
struct ieee80211com *ic = vap->iv_ic;
struct ieee80211_scan_state *ss;
IEEE80211_LOCK(ic);
ss = ic->ic_scan;
if (ss != NULL && ss->ss_vap == vap) {
if (ic->ic_flags & IEEE80211_F_SCAN) {
/* XXX callout_drain */
callout_stop(&SCAN_PRIVATE(ss)->ss_scan_timer);
ic->ic_flags &= ~IEEE80211_F_SCAN;
}
if (ss->ss_ops != NULL) {
ss->ss_ops->scan_detach(ss);
ss->ss_ops = NULL;
}
ss->ss_vap = NULL;
}
IEEE80211_UNLOCK(ic);
}
/*
* Simple-minded scanner module support.
*/
static const char *scan_modnames[IEEE80211_OPMODE_MAX] = {
"wlan_scan_sta", /* IEEE80211_M_IBSS */
"wlan_scan_sta", /* IEEE80211_M_STA */
"wlan_scan_wds", /* IEEE80211_M_WDS */
"wlan_scan_sta", /* IEEE80211_M_AHDEMO */
"wlan_scan_ap", /* IEEE80211_M_HOSTAP */
"wlan_scan_monitor", /* IEEE80211_M_MONITOR */
};
static const struct ieee80211_scanner *scanners[IEEE80211_OPMODE_MAX];
const struct ieee80211_scanner *
ieee80211_scanner_get(enum ieee80211_opmode mode)
{
if (mode >= IEEE80211_OPMODE_MAX)
return NULL;
if (scanners[mode] == NULL)
ieee80211_load_module(scan_modnames[mode]);
return scanners[mode];
}
void
ieee80211_scanner_register(enum ieee80211_opmode mode,
const struct ieee80211_scanner *scan)
{
if (mode >= IEEE80211_OPMODE_MAX)
return;
scanners[mode] = scan;
}
void
ieee80211_scanner_unregister(enum ieee80211_opmode mode,
const struct ieee80211_scanner *scan)
{
if (mode >= IEEE80211_OPMODE_MAX)
return;
if (scanners[mode] == scan)
scanners[mode] = NULL;
}
void
ieee80211_scanner_unregister_all(const struct ieee80211_scanner *scan)
{
int m;
for (m = 0; m < IEEE80211_OPMODE_MAX; m++)
if (scanners[m] == scan)
scanners[m] = NULL;
}
/*
* Update common scanner state to reflect the current
* operating mode. This is called when the state machine
* is transitioned to RUN state w/o scanning--e.g. when
* operating in monitor mode. The purpose of this is to
* ensure later callbacks find ss_ops set to properly
* reflect current operating mode.
*/
static void
scan_update_locked(struct ieee80211vap *vap,
const struct ieee80211_scanner *scan)
{
struct ieee80211com *ic = vap->iv_ic;
struct ieee80211_scan_state *ss = ic->ic_scan;
IEEE80211_LOCK_ASSERT(ic);
#ifdef IEEE80211_DEBUG
if (ss->ss_vap != vap || ss->ss_ops != scan) {
IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
"%s: current scanner is <%s:%s>, switch to <%s:%s>\n",
__func__,
ss->ss_vap != NULL ?
ss->ss_vap->iv_ifp->if_xname : "none",
ss->ss_vap != NULL ?
ieee80211_opmode_name[ss->ss_vap->iv_opmode] : "none",
vap->iv_ifp->if_xname,
ieee80211_opmode_name[vap->iv_opmode]);
}
#endif
ss->ss_vap = vap;
if (ss->ss_ops != scan) {
/*
* Switch scanners; detach old, attach new. Special
* case where a single scan module implements multiple
* policies by using different scan ops but a common
* core. We assume if the old and new attach methods
* are identical then it's ok to just change ss_ops
* and not flush the internal state of the module.
*/
if (scan == NULL || ss->ss_ops == NULL ||
ss->ss_ops->scan_attach != scan->scan_attach) {
if (ss->ss_ops != NULL)
ss->ss_ops->scan_detach(ss);
if (scan != NULL && !scan->scan_attach(ss)) {
/* XXX attach failure */
/* XXX stat+msg */
scan = NULL;
}
}
ss->ss_ops = scan;
}
}
static void
change_channel(struct ieee80211com *ic,
struct ieee80211_channel *chan)
{
ic->ic_curchan = chan;
ic->ic_set_channel(ic);
}
static char
channel_type(const struct ieee80211_channel *c)
{
if (IEEE80211_IS_CHAN_ST(c))
return 'S';
if (IEEE80211_IS_CHAN_108A(c))
return 'T';
if (IEEE80211_IS_CHAN_108G(c))
return 'G';
if (IEEE80211_IS_CHAN_HT(c))
return 'n';
if (IEEE80211_IS_CHAN_A(c))
return 'a';
if (IEEE80211_IS_CHAN_ANYG(c))
return 'g';
if (IEEE80211_IS_CHAN_B(c))
return 'b';
return 'f';
}
void
ieee80211_scan_dump_channels(const struct ieee80211_scan_state *ss)
{
struct ieee80211com *ic = ss->ss_vap->iv_ic;
const char *sep;
int i;
sep = "";
for (i = ss->ss_next; i < ss->ss_last; i++) {
const struct ieee80211_channel *c = ss->ss_chans[i];
printf("%s%u%c", sep, ieee80211_chan2ieee(ic, c),
channel_type(c));
sep = ", ";
}
}
#ifdef IEEE80211_DEBUG
static void
scan_dump(struct ieee80211_scan_state *ss)
{
struct ieee80211vap *vap = ss->ss_vap;
if_printf(vap->iv_ifp, "scan set ");
ieee80211_scan_dump_channels(ss);
printf(" dwell min %lu max %lu\n", ss->ss_mindwell, ss->ss_maxdwell);
}
#endif /* IEEE80211_DEBUG */
/*
* Enable station power save mode and start/restart the scanning thread.
*/
static void
scan_restart_pwrsav(void *arg)
{
struct scan_state *ss = (struct scan_state *) arg;
struct ieee80211vap *vap = ss->base.ss_vap;
struct ieee80211com *ic = vap->iv_ic;
int ticksdelay;
ieee80211_sta_pwrsave(vap, 1);
/*
* Use an initial 1ms delay so the null
* data frame has a chance to go out.
* XXX 1ms is a lot, better to trigger scan
* on tx complete.
*/
ticksdelay = msecs_to_ticks(1);
if (ticksdelay < 1)
ticksdelay = 1;
ic->ic_scan_start(ic); /* notify driver */
ss->ss_scanend = ticks + ticksdelay + ss->ss_duration;
ss->ss_iflags |= ISCAN_START;
callout_reset(&ss->ss_scan_timer, ticksdelay, scan_next, ss);
}
/*
* Start/restart scanning. If we're operating in station mode
* and associated notify the ap we're going into power save mode
* and schedule a callback to initiate the work (where there's a
* better context for doing the work). Otherwise, start the scan
* directly.
*/
static int
scan_restart(struct scan_state *ss, u_int duration)
{
struct ieee80211vap *vap = ss->base.ss_vap;
struct ieee80211com *ic = vap->iv_ic;
int defer = 0;
if (ss->base.ss_next == ss->base.ss_last) {
IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
"%s: no channels to scan\n", __func__);
return 0;
}
if (vap->iv_opmode == IEEE80211_M_STA &&
vap->iv_state == IEEE80211_S_RUN) {
if ((vap->iv_bss->ni_flags & IEEE80211_NODE_PWR_MGT) == 0) {
/*
* Initiate power save before going off-channel.
* Note that we cannot do this directly because
* of locking issues; instead we defer it to a
* tasklet.
*/
ss->ss_duration = duration;
defer = 1;
}
}
if (!defer) {
ic->ic_scan_start(ic); /* notify driver */
ss->ss_scanend = ticks + duration;
ss->ss_iflags |= ISCAN_START;
callout_reset(&ss->ss_scan_timer, 0, scan_next, ss);
} else
scan_restart_pwrsav(ss);
return 1;
}
static void
copy_ssid(struct ieee80211vap *vap, struct ieee80211_scan_state *ss,
int nssid, const struct ieee80211_scan_ssid ssids[])
{
if (nssid > IEEE80211_SCAN_MAX_SSID) {
/* XXX printf */
IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
"%s: too many ssid %d, ignoring all of them\n",
__func__, nssid);
return;
}
memcpy(ss->ss_ssid, ssids, nssid * sizeof(ssids[0]));
ss->ss_nssid = nssid;
}
/*
* Start a scan unless one is already going.
*/
static int
start_scan_locked(const struct ieee80211_scanner *scan,
struct ieee80211vap *vap, int flags, u_int duration,
u_int mindwell, u_int maxdwell,
u_int nssid, const struct ieee80211_scan_ssid ssids[])
{
struct ieee80211com *ic = vap->iv_ic;
struct ieee80211_scan_state *ss = ic->ic_scan;
IEEE80211_LOCK_ASSERT(ic);
if (ic->ic_flags & IEEE80211_F_CSAPENDING) {
IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
"%s: scan inhibited by pending channel change\n", __func__);
} else if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) {
IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
"%s: %s scan, duration %u mindwell %u maxdwell %u, desired mode %s, %s%s%s%s%s%s\n"
, __func__
, flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive"
, duration, mindwell, maxdwell
, ieee80211_phymode_name[vap->iv_des_mode]
, flags & IEEE80211_SCAN_FLUSH ? "flush" : "append"
, flags & IEEE80211_SCAN_NOPICK ? ", nopick" : ""
, flags & IEEE80211_SCAN_NOJOIN ? ", nojoin" : ""
, flags & IEEE80211_SCAN_NOBCAST ? ", nobcast" : ""
, flags & IEEE80211_SCAN_PICK1ST ? ", pick1st" : ""
, flags & IEEE80211_SCAN_ONCE ? ", once" : ""
);
scan_update_locked(vap, scan);
if (ss->ss_ops != NULL) {
if ((flags & IEEE80211_SCAN_NOSSID) == 0)
copy_ssid(vap, ss, nssid, ssids);
/* NB: top 4 bits for internal use */
ss->ss_flags = flags & 0xfff;
if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
vap->iv_stats.is_scan_active++;
else
vap->iv_stats.is_scan_passive++;
if (flags & IEEE80211_SCAN_FLUSH)
ss->ss_ops->scan_flush(ss);
/* NB: flush frames rx'd before 1st channel change */
SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
ss->ss_next = 0;
ss->ss_mindwell = mindwell;
ss->ss_maxdwell = maxdwell;
ss->ss_ops->scan_start(ss, vap);
#ifdef IEEE80211_DEBUG
if (ieee80211_msg_scan(vap))
scan_dump(ss);
#endif /* IEEE80211_DEBUG */
if (scan_restart(SCAN_PRIVATE(ss), duration))
ic->ic_flags |= IEEE80211_F_SCAN;
}
} else {
IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
"%s: %s scan already in progress\n", __func__,
ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive");
}
return (ic->ic_flags & IEEE80211_F_SCAN);
}
/*
* Start a scan unless one is already going.
*/
int
ieee80211_start_scan(struct ieee80211vap *vap, int flags,
u_int duration, u_int mindwell, u_int maxdwell,
u_int nssid, const struct ieee80211_scan_ssid ssids[])
{
struct ieee80211com *ic = vap->iv_ic;
const struct ieee80211_scanner *scan;
int result;
scan = ieee80211_scanner_get(vap->iv_opmode);
if (scan == NULL) {
IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
"%s: no scanner support for %s mode\n",
__func__, ieee80211_opmode_name[vap->iv_opmode]);
/* XXX stat */
return 0;
}
IEEE80211_LOCK(ic);
result = start_scan_locked(scan, vap, flags, duration,
mindwell, maxdwell, nssid, ssids);
IEEE80211_UNLOCK(ic);
return result;
}
/*
* Check the scan cache for an ap/channel to use; if that
* fails then kick off a new scan.
*/
int
ieee80211_check_scan(struct ieee80211vap *vap, int flags,
u_int duration, u_int mindwell, u_int maxdwell,
u_int nssid, const struct ieee80211_scan_ssid ssids[])
{
struct ieee80211com *ic = vap->iv_ic;
struct ieee80211_scan_state *ss = ic->ic_scan;
const struct ieee80211_scanner *scan;
int result;
scan = ieee80211_scanner_get(vap->iv_opmode);
if (scan == NULL) {
IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
"%s: no scanner support for %s mode\n",
__func__, vap->iv_opmode);
/* XXX stat */
return 0;
}
/*
* Check if there's a list of scan candidates already.
* XXX want more than the ap we're currently associated with
*/
IEEE80211_LOCK(ic);
IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
"%s: %s scan, %s%s%s%s%s\n"
, __func__
, flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive"
, flags & IEEE80211_SCAN_FLUSH ? "flush" : "append"
, flags & IEEE80211_SCAN_NOPICK ? ", nopick" : ""
, flags & IEEE80211_SCAN_NOJOIN ? ", nojoin" : ""
, flags & IEEE80211_SCAN_PICK1ST ? ", pick1st" : ""
, flags & IEEE80211_SCAN_ONCE ? ", once" : ""
);
if (ss->ss_ops != scan) {
/* XXX re-use cache contents? e.g. adhoc<->sta */
flags |= IEEE80211_SCAN_FLUSH;
}
scan_update_locked(vap, scan);
if (ss->ss_ops != NULL) {
/* XXX verify ss_ops matches vap->iv_opmode */
if ((flags & IEEE80211_SCAN_NOSSID) == 0) {
/*
* Update the ssid list and mark flags so if
* we call start_scan it doesn't duplicate work.
*/
copy_ssid(vap, ss, nssid, ssids);
flags |= IEEE80211_SCAN_NOSSID;
}
if ((ic->ic_flags & IEEE80211_F_SCAN) == 0 &&
(flags & IEEE80211_SCAN_FLUSH) == 0 &&
time_before(ticks, ic->ic_lastscan + vap->iv_scanvalid)) {
/*
* We're not currently scanning and the cache is
* deemed hot enough to consult. Lock out others
* by marking IEEE80211_F_SCAN while we decide if
* something is already in the scan cache we can
* use. Also discard any frames that might come
* in while temporarily marked as scanning.
*/
SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
ic->ic_flags |= IEEE80211_F_SCAN;
/* NB: need to use supplied flags in check */
ss->ss_flags = flags & 0xff;
result = ss->ss_ops->scan_end(ss, vap);
ic->ic_flags &= ~IEEE80211_F_SCAN;
SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_DISCARD;
if (result) {
ieee80211_notify_scan_done(vap);
IEEE80211_UNLOCK(ic);
return 1;
}
}
}
result = start_scan_locked(scan, vap, flags, duration,
mindwell, maxdwell, nssid, ssids);
IEEE80211_UNLOCK(ic);
return result;
}
/*
* Check the scan cache for an ap/channel to use; if that fails
* then kick off a scan using the current settings.
*/
int
ieee80211_check_scan_current(struct ieee80211vap *vap)
{
return ieee80211_check_scan(vap,
IEEE80211_SCAN_ACTIVE,
IEEE80211_SCAN_FOREVER, 0, 0,
vap->iv_des_nssid, vap->iv_des_ssid);
}
/*
* Restart a previous scan. If the previous scan completed
* then we start again using the existing channel list.
*/
int
ieee80211_bg_scan(struct ieee80211vap *vap, int flags)
{
struct ieee80211com *ic = vap->iv_ic;
struct ieee80211_scan_state *ss = ic->ic_scan;
const struct ieee80211_scanner *scan;
scan = ieee80211_scanner_get(vap->iv_opmode);
if (scan == NULL) {
IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
"%s: no scanner support for %s mode\n",
__func__, vap->iv_opmode);
/* XXX stat */
return 0;
}
IEEE80211_LOCK(ic);
if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) {
u_int duration;
/*
* Go off-channel for a fixed interval that is large
* enough to catch most ap's but short enough that
* we can return on-channel before our listen interval
* expires.
*/
duration = IEEE80211_SCAN_OFFCHANNEL;
IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
"%s: %s scan, ticks %u duration %lu\n", __func__,
ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive",
ticks, duration);
scan_update_locked(vap, scan);
if (ss->ss_ops != NULL) {
ss->ss_vap = vap;
/*
* A background scan does not select a new sta; it
* just refreshes the scan cache. Also, indicate
* the scan logic should follow the beacon schedule:
* we go off-channel and scan for a while, then
* return to the bss channel to receive a beacon,
* then go off-channel again. All during this time
* we notify the ap we're in power save mode. When
* the scan is complete we leave power save mode.
* If any beacon indicates there are frames pending
* for us then we drop out of power save mode
* (and background scan) automatically by way of the
* usual sta power save logic.
*/
ss->ss_flags |= IEEE80211_SCAN_NOPICK
| IEEE80211_SCAN_BGSCAN
| flags
;
/* if previous scan completed, restart */
if (ss->ss_next >= ss->ss_last) {
if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
vap->iv_stats.is_scan_active++;
else
vap->iv_stats.is_scan_passive++;
/*
* NB: beware of the scan cache being flushed;
* if the channel list is empty use the
* scan_start method to populate it.
*/
ss->ss_next = 0;
if (ss->ss_last != 0)
ss->ss_ops->scan_restart(ss, vap);
else {
ss->ss_ops->scan_start(ss, vap);
#ifdef IEEE80211_DEBUG
if (ieee80211_msg_scan(vap))
scan_dump(ss);
#endif /* IEEE80211_DEBUG */
}
}
/* NB: flush frames rx'd before 1st channel change */
SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
ss->ss_maxdwell = duration;
if (scan_restart(SCAN_PRIVATE(ss), duration)) {
ic->ic_flags |= IEEE80211_F_SCAN;
ic->ic_flags_ext |= IEEE80211_FEXT_BGSCAN;
}
} else {
/* XXX msg+stat */
}
} else {
IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
"%s: %s scan already in progress\n", __func__,
ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive");
}
IEEE80211_UNLOCK(ic);
/* NB: racey, does it matter? */
return (ic->ic_flags & IEEE80211_F_SCAN);
}
/*
* Cancel any scan currently going on for the specified vap.
*/
void
ieee80211_cancel_scan(struct ieee80211vap *vap)
{
struct ieee80211com *ic = vap->iv_ic;
struct ieee80211_scan_state *ss = ic->ic_scan;
IEEE80211_LOCK(ic);
if ((ic->ic_flags & IEEE80211_F_SCAN) &&
ss->ss_vap == vap &&
(SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0) {
IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
"%s: cancel %s scan\n", __func__,
ss->ss_flags & IEEE80211_SCAN_ACTIVE ?
"active" : "passive");
/* clear bg scan NOPICK and mark cancel request */
ss->ss_flags &= ~IEEE80211_SCAN_NOPICK;
SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_CANCEL;
/* force it to fire asap */
callout_reset(&SCAN_PRIVATE(ss)->ss_scan_timer,
0, scan_next, ss);
}
IEEE80211_UNLOCK(ic);
}
/*
* Cancel any scan currently going on.
*/
void
ieee80211_cancel_anyscan(struct ieee80211vap *vap)
{
struct ieee80211com *ic = vap->iv_ic;
struct ieee80211_scan_state *ss = ic->ic_scan;
IEEE80211_LOCK(ic);
if ((ic->ic_flags & IEEE80211_F_SCAN) &&
(SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0) {
IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
"%s: cancel %s scan\n", __func__,
ss->ss_flags & IEEE80211_SCAN_ACTIVE ?
"active" : "passive");
/* clear bg scan NOPICK and mark cancel request */
ss->ss_flags &= ~IEEE80211_SCAN_NOPICK;
SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_CANCEL;
/* force it to fire asap */
callout_reset(&SCAN_PRIVATE(ss)->ss_scan_timer,
0, scan_next, ss);
}
IEEE80211_UNLOCK(ic);
}
/*
* Public access to scan_next for drivers that manage
* scanning themselves (e.g. for firmware-based devices).
*/
void
ieee80211_scan_next(struct ieee80211vap *vap)
{
struct ieee80211com *ic = vap->iv_ic;
struct ieee80211_scan_state *ss = ic->ic_scan;
callout_reset(&SCAN_PRIVATE(ss)->ss_scan_timer, 0, scan_next, ss);
}
/*
* Public access to scan_next for drivers that are not able to scan single
* channels (e.g. for firmware-based devices).
*/
void
ieee80211_scan_done(struct ieee80211vap *vap)
{
struct ieee80211com *ic = vap->iv_ic;
struct ieee80211_scan_state *ss;
IEEE80211_LOCK(ic);
ss = ic->ic_scan;
ss->ss_next = ss->ss_last; /* all channels are complete */
scan_next(ss);
IEEE80211_UNLOCK(ic);
}
/*
* Probe the curent channel, if allowed, while scanning.
* If the channel is not marked passive-only then send
* a probe request immediately. Otherwise mark state and
* listen for beacons on the channel; if we receive something
* then we'll transmit a probe request.
*/
void
ieee80211_probe_curchan(struct ieee80211vap *vap, int force)
{
struct ieee80211com *ic = vap->iv_ic;
struct ieee80211_scan_state *ss = ic->ic_scan;
struct ifnet *ifp = vap->iv_ifp;
int i;
if ((ic->ic_curchan->ic_flags & IEEE80211_CHAN_PASSIVE) && !force) {
ic->ic_flags_ext |= IEEE80211_FEXT_PROBECHAN;
return;
}
/*
* Send directed probe requests followed by any
* broadcast probe request.
* XXX remove dependence on ic/vap->iv_bss
*/
for (i = 0; i < ss->ss_nssid; i++)
ieee80211_send_probereq(vap->iv_bss,
vap->iv_myaddr, ifp->if_broadcastaddr,
ifp->if_broadcastaddr,
ss->ss_ssid[i].ssid, ss->ss_ssid[i].len);
if ((ss->ss_flags & IEEE80211_SCAN_NOBCAST) == 0)
ieee80211_send_probereq(vap->iv_bss,
vap->iv_myaddr, ifp->if_broadcastaddr,
ifp->if_broadcastaddr,
"", 0);
}
/*
* Scan curchan. If this is an active scan and the channel
* is not marked passive then send probe request frame(s).
* Arrange for the channel change after maxdwell ticks.
*/
static void
scan_curchan(struct ieee80211_scan_state *ss, unsigned long maxdwell)
{
struct ieee80211vap *vap = ss->ss_vap;
IEEE80211_LOCK_ASSERT(vap->iv_ic);
if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
ieee80211_probe_curchan(vap, 0);
callout_reset(&SCAN_PRIVATE(ss)->ss_scan_timer,
maxdwell, scan_next, ss);
}
/*
* Handle mindwell requirements completed; initiate a channel
* change to the next channel asap.
*/
static void
scan_mindwell(struct ieee80211_scan_state *ss)
{
callout_reset(&SCAN_PRIVATE(ss)->ss_scan_timer, 0, scan_next, ss);
}
/*
* Switch to the next channel marked for scanning.
*/
static void
scan_next(void *arg)
{
#define ISCAN_REP (ISCAN_MINDWELL | ISCAN_START | ISCAN_DISCARD)
struct ieee80211_scan_state *ss = (struct ieee80211_scan_state *) arg;
struct ieee80211vap *vap = ss->ss_vap;
struct ieee80211com *ic = vap->iv_ic;
struct ieee80211_channel *chan;
unsigned long maxdwell, scanend;
int scandone;
IEEE80211_LOCK_ASSERT(ic);
if ((ic->ic_flags & IEEE80211_F_SCAN) == 0)
return;
again:
scandone = (ss->ss_next >= ss->ss_last) ||
(SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) != 0;
scanend = SCAN_PRIVATE(ss)->ss_scanend;
if (!scandone &&
(ss->ss_flags & IEEE80211_SCAN_GOTPICK) == 0 &&
((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_START) ||
time_before(ticks + ss->ss_mindwell, scanend))) {
chan = ss->ss_chans[ss->ss_next++];
/*
* Watch for truncation due to the scan end time.
*/
if (time_after(ticks + ss->ss_maxdwell, scanend))
maxdwell = scanend - ticks;
else
maxdwell = ss->ss_maxdwell;
IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
"%s: chan %3d%c -> %3d%c [%s, dwell min %lu max %lu]\n",
__func__,
ieee80211_chan2ieee(ic, ic->ic_curchan),
channel_type(ic->ic_curchan),
ieee80211_chan2ieee(ic, chan), channel_type(chan),
(ss->ss_flags & IEEE80211_SCAN_ACTIVE) &&
(chan->ic_flags & IEEE80211_CHAN_PASSIVE) == 0 ?
"active" : "passive",
ss->ss_mindwell, maxdwell);
/*
* Potentially change channel and phy mode.
*/
change_channel(ic, chan);
/*
* Scan curchan. Drivers for "intelligent hardware"
* override ic_scan_curchan to tell the device to do
* the work. Otherwise we manage the work outselves;
* sending a probe request (as needed), and arming the
* timeout to switch channels after maxdwell ticks.
*/
ic->ic_scan_curchan(ss, maxdwell);
SCAN_PRIVATE(ss)->ss_chanmindwell = ticks + ss->ss_mindwell;
/* clear mindwell lock and initial channel change flush */
SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_REP;
} else {
ic->ic_scan_end(ic); /* notify driver */
/*
* Record scan complete time. Note that we also do
* this when canceled so any background scan will
* not be restarted for a while.
*/
if (scandone)
ic->ic_lastscan = ticks;
/* return to the bss channel */
if (ic->ic_bsschan != IEEE80211_CHAN_ANYC &&
ic->ic_curchan != ic->ic_bsschan)
ieee80211_setcurchan(ic, ic->ic_bsschan);
/* clear internal flags and any indication of a pick */
SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_REP;
ss->ss_flags &= ~IEEE80211_SCAN_GOTPICK;
/*
* If not canceled and scan completed, do post-processing.
* If the callback function returns 0, then it wants to
* continue/restart scanning. Unfortunately we needed to
* notify the driver to end the scan above to avoid having
* rx frames alter the scan candidate list.
*/
if ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0 &&
!ss->ss_ops->scan_end(ss, vap) &&
(ss->ss_flags & IEEE80211_SCAN_ONCE) == 0 &&
time_before(ticks + ss->ss_mindwell, scanend)) {
IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
"%s: done, restart "
"[ticks %u, dwell min %lu scanend %lu]\n",
__func__,
ticks, ss->ss_mindwell, scanend);
ss->ss_next = 0; /* reset to begining */
if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
vap->iv_stats.is_scan_active++;
else
vap->iv_stats.is_scan_passive++;
ss->ss_ops->scan_restart(ss, vap); /* XXX? */
ic->ic_scan_start(ic); /* notify driver */
goto again;
} else {
/* past here, scandone is ``true'' if not in bg mode */
if ((ss->ss_flags & IEEE80211_SCAN_BGSCAN) == 0)
scandone = 1;
IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
"%s: %s, "
"[ticks %u, dwell min %lu scanend %lu]\n",
__func__, scandone ? "done" : "stopped",
ticks, ss->ss_mindwell, scanend);
/*
* Clear the SCAN bit first in case frames are
* pending on the station power save queue. If
* we defer this then the dispatch of the frames
* may generate a request to cancel scanning.
*/
ic->ic_flags &= ~IEEE80211_F_SCAN;
/*
* Drop out of power save mode when a scan has
* completed. If this scan was prematurely terminated
* because it is a background scan then don't notify
* the ap; we'll either return to scanning after we
* receive the beacon frame or we'll drop out of power
* save mode because the beacon indicates we have frames
* waiting for us.
*/
if (scandone) {
ieee80211_sta_pwrsave(vap, 0);
if (ss->ss_next >= ss->ss_last) {
ieee80211_notify_scan_done(vap);
ic->ic_flags_ext &= ~IEEE80211_FEXT_BGSCAN;
}
}
SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_CANCEL;
ss->ss_flags &=
~(IEEE80211_SCAN_ONCE | IEEE80211_SCAN_PICK1ST);
}
}
#undef ISCAN_REP
}
#ifdef IEEE80211_DEBUG
static void
dump_country(const uint8_t *ie)
{
const struct ieee80211_country_ie *cie =
(const struct ieee80211_country_ie *) ie;
int i, nbands, schan, nchan;
if (cie->len < 3) {
printf(" <bogus country ie, len %d>", cie->len);
return;
}
printf(" country [%c%c%c", cie->cc[0], cie->cc[1], cie->cc[2]);
nbands = (cie->len - 3) / sizeof(cie->band[0]);
for (i = 0; i < nbands; i++) {
schan = cie->band[i].schan;
nchan = cie->band[i].nchan;
if (nchan != 1)
printf(" %u-%u,%u", schan, schan + nchan-1,
cie->band[i].maxtxpwr);
else
printf(" %u,%u", schan, cie->band[i].maxtxpwr);
}
printf("]");
}
static void
dump_probe_beacon(uint8_t subtype, int isnew,
const uint8_t mac[IEEE80211_ADDR_LEN],
const struct ieee80211_scanparams *sp, int rssi)
{
printf("[%s] %s%s on chan %u (bss chan %u) ",
ether_sprintf(mac), isnew ? "new " : "",
ieee80211_mgt_subtype_name[subtype >> IEEE80211_FC0_SUBTYPE_SHIFT],
sp->chan, sp->bchan);
ieee80211_print_essid(sp->ssid + 2, sp->ssid[1]);
printf(" rssi %d\n", rssi);
if (isnew) {
printf("[%s] caps 0x%x bintval %u erp 0x%x",
ether_sprintf(mac), sp->capinfo, sp->bintval, sp->erp);
if (sp->country != NULL)
dump_country(sp->country);
printf("\n");
}
}
#endif /* IEEE80211_DEBUG */
/*
* Process a beacon or probe response frame.
*/
void
ieee80211_add_scan(struct ieee80211vap *vap,
const struct ieee80211_scanparams *sp,
const struct ieee80211_frame *wh,
int subtype, int rssi, int noise, int rstamp)
{
struct ieee80211com *ic = vap->iv_ic;
struct ieee80211_scan_state *ss = ic->ic_scan;
/* XXX locking */
/*
* Frames received during startup are discarded to avoid
* using scan state setup on the initial entry to the timer
* callback. This can occur because the device may enable
* rx prior to our doing the initial channel change in the
* timer routine.
*/
if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_DISCARD)
return;
#ifdef IEEE80211_DEBUG
if (ieee80211_msg_scan(vap) && (ic->ic_flags & IEEE80211_F_SCAN))
dump_probe_beacon(subtype, 1, wh->i_addr2, sp, rssi);
#endif
if (ss->ss_ops != NULL &&
ss->ss_ops->scan_add(ss, sp, wh, subtype, rssi, noise, rstamp)) {
/*
* If we've reached the min dwell time terminate
* the timer so we'll switch to the next channel.
*/
if ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_MINDWELL) == 0 &&
time_after_eq(ticks, SCAN_PRIVATE(ss)->ss_chanmindwell)) {
IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
"%s: chan %3d%c min dwell met (%u > %lu)\n",
__func__,
ieee80211_chan2ieee(ic, ic->ic_curchan),
channel_type(ic->ic_curchan),
ticks, SCAN_PRIVATE(ss)->ss_chanmindwell);
SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_MINDWELL;
/*
* NB: trigger at next clock tick or wait for the
* hardware.
*/
ic->ic_scan_mindwell(ss);
}
}
}
/*
* Timeout/age scan cache entries; called from sta timeout
* timer (XXX should be self-contained).
*/
void
ieee80211_scan_timeout(struct ieee80211com *ic)
{
struct ieee80211_scan_state *ss = ic->ic_scan;
if (ss->ss_ops != NULL)
ss->ss_ops->scan_age(ss);
}
/*
* Mark a scan cache entry after a successful associate.
*/
void
ieee80211_scan_assoc_success(struct ieee80211vap *vap, const uint8_t mac[])
{
struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
if (ss->ss_ops != NULL) {
IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_SCAN,
mac, "%s", __func__);
ss->ss_ops->scan_assoc_success(ss, mac);
}
}
/*
* Demerit a scan cache entry after failing to associate.
*/
void
ieee80211_scan_assoc_fail(struct ieee80211vap *vap,
const uint8_t mac[], int reason)
{
struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
if (ss->ss_ops != NULL) {
IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_SCAN, mac,
"%s: reason %u", __func__, reason);
ss->ss_ops->scan_assoc_fail(ss, mac, reason);
}
}
/*
* Iterate over the contents of the scan cache.
*/
void
ieee80211_scan_iterate(struct ieee80211vap *vap,
ieee80211_scan_iter_func *f, void *arg)
{
struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
if (ss->ss_ops != NULL)
ss->ss_ops->scan_iterate(ss, f, arg);
}
/*
* Flush the contents of the scan cache.
*/
void
ieee80211_scan_flush(struct ieee80211vap *vap)
{
struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan;
if (ss->ss_ops != NULL && ss->ss_vap == vap) {
IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s\n", __func__);
ss->ss_ops->scan_flush(ss);
}
}
/*
* Check the scan cache for an ap/channel to use; if that
* fails then kick off a new scan.
*/
struct ieee80211_channel *
ieee80211_scan_pickchannel(struct ieee80211com *ic, int flags)
{
struct ieee80211_scan_state *ss = ic->ic_scan;
IEEE80211_LOCK_ASSERT(ic);
if (ss == NULL || ss->ss_ops == NULL || ss->ss_vap == NULL) {
/* XXX printf? */
return NULL;
}
if (ss->ss_ops->scan_pickchan == NULL) {
IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN,
"%s: scan module does not support picking a channel, "
"opmode %s\n", __func__, ss->ss_vap->iv_opmode);
return NULL;
}
return ss->ss_ops->scan_pickchan(ss, flags);
}
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