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freebsd/sys/net80211/ieee80211_scan.c

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Update 802.11 wireless support: o major overhaul of the way channels are handled: channels are now fully enumerated and uniquely identify the operating characteristics; these changes are visible to user applications which require changes o make scanning support independent of the state machine to enable background scanning and roaming o move scanning support into loadable modules based on the operating mode to enable different policies and reduce the memory footprint on systems w/ constrained resources o add background scanning in station mode (no support for adhoc/ibss mode yet) o significantly speedup sta mode scanning with a variety of techniques o add roaming support when background scanning is supported; for now we use a simple algorithm to trigger a roam: we threshold the rssi and tx rate, if either drops too low we try to roam to a new ap o add tx fragmentation support o add first cut at 802.11n support: this code works with forthcoming drivers but is incomplete; it's included now to establish a baseline for other drivers to be developed and for user applications o adjust max_linkhdr et. al. to reflect 802.11 requirements; this eliminates prepending mbufs for traffic generated locally o add support for Atheros protocol extensions; mainly the fast frames encapsulation (note this can be used with any card that can tx+rx large frames correctly) o add sta support for ap's that beacon both WPA1+2 support o change all data types from bsd-style to posix-style o propagate noise floor data from drivers to net80211 and on to user apps o correct various issues in the sta mode state machine related to handling authentication and association failures o enable the addition of sta mode power save support for drivers that need net80211 support (not in this commit) o remove old WI compatibility ioctls (wicontrol is officially dead) o change the data structures returned for get sta info and get scan results so future additions will not break user apps o fixed tx rate is now maintained internally as an ieee rate and not an index into the rate set; this needs to be extended to deal with multi-mode operation o add extended channel specifications to radiotap to enable 11n sniffing Drivers: o ath: add support for bg scanning, tx fragmentation, fast frames, dynamic turbo (lightly tested), 11n (sniffing only and needs new hal) o awi: compile tested only o ndis: lightly tested o ipw: lightly tested o iwi: add support for bg scanning (well tested but may have some rough edges) o ral, ural, rum: add suppoort for bg scanning, calibrate rssi data o wi: lightly tested This work is based on contributions by Atheros, kmacy, sephe, thompsa, mlaier, kevlo, and others. Much of the scanning work was supported by Atheros. The 11n work was supported by Marvell.
2007-06-11 03:36:55 +00:00
/*-
* Copyright (c) 2002-2007 Sam Leffler, Errno Consulting
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* IEEE 802.11 scanning support.
*/
#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).
*/
#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 */
static void scan_restart_pwrsav(void *);
static void scan_curchan(struct ieee80211com *, unsigned long);
static void scan_mindwell(struct ieee80211com *);
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;
ic->ic_roaming = IEEE80211_ROAMING_AUTO;
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(&ss->ss_scan_timer, CALLOUT_MPSAFE);
ic->ic_scan = &ss->base;
ic->ic_scan_curchan = scan_curchan;
ic->ic_scan_mindwell = scan_mindwell;
ic->ic_bgscanidle = (IEEE80211_BGSCAN_IDLE_DEFAULT*1000)/hz;
ic->ic_bgscanintvl = IEEE80211_BGSCAN_INTVAL_DEFAULT*hz;
ic->ic_scanvalid = IEEE80211_SCAN_VALID_DEFAULT*hz;
ic->ic_roam.rssi11a = ROAM_RSSI_11A_DEFAULT;
ic->ic_roam.rssi11b = ROAM_RSSI_11B_DEFAULT;
ic->ic_roam.rssi11bOnly = ROAM_RSSI_11BONLY_DEFAULT;
ic->ic_roam.rate11a = ROAM_RATE_11A_DEFAULT;
ic->ic_roam.rate11b = ROAM_RATE_11B_DEFAULT;
ic->ic_roam.rate11bOnly = ROAM_RATE_11BONLY_DEFAULT;
}
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);
}
}
/*
* Simple-minded scanner module support.
*/
#define IEEE80211_SCANNER_MAX (IEEE80211_M_MONITOR+1)
static const char *scan_modnames[IEEE80211_SCANNER_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_4", /* n/a */
"wlan_scan_5", /* n/a */
"wlan_scan_ap", /* IEEE80211_M_HOSTAP */
"wlan_scan_7", /* n/a */
"wlan_scan_monitor", /* IEEE80211_M_MONITOR */
};
static const struct ieee80211_scanner *scanners[IEEE80211_SCANNER_MAX];
const struct ieee80211_scanner *
ieee80211_scanner_get(enum ieee80211_opmode mode)
{
if (mode >= IEEE80211_SCANNER_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_SCANNER_MAX)
return;
scanners[mode] = scan;
}
void
ieee80211_scanner_unregister(enum ieee80211_opmode mode,
const struct ieee80211_scanner *scan)
{
if (mode >= IEEE80211_SCANNER_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_SCANNER_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.
*/
int
ieee80211_scan_update(struct ieee80211com *ic)
{
struct ieee80211_scan_state *ss = ic->ic_scan;
const struct ieee80211_scanner *scan;
scan = ieee80211_scanner_get(ic->ic_opmode);
IEEE80211_LOCK(ic);
if (scan == NULL) {
IEEE80211_DPRINTF(ic, IEEE80211_MSG_SCAN,
"%s: no scanner support for mode %u\n",
__func__, ic->ic_opmode);
/* XXX stat */
}
ss->ss_ic = ic;
if (ss->ss_ops != scan) {
/* switch scanners; detach old, attach new */
if (ss->ss_ops != NULL)
ss->ss_ops->scan_detach(ss);
if (scan != NULL && !scan->scan_attach(ss)) {
/* XXX attach failure */
/* XXX stat+msg */
ss->ss_ops = NULL;
} else
ss->ss_ops = scan;
}
IEEE80211_UNLOCK(ic);
return (scan != NULL);
}
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_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 = ", ";
}
}
/*
* 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 ieee80211com *ic = ss->base.ss_ic;
int delay;
ieee80211_sta_pwrsave(ic, 1);
/*
* Use an initial 1ms delay to insure the null
* data frame has a chance to go out.
* XXX 1ms is a lot, better to trigger scan
* on tx complete.
*/
delay = hz/1000;
if (delay < 1)
delay = 1;
ic->ic_scan_start(ic); /* notify driver */
ss->ss_scanend = ticks + delay + ss->ss_duration;
ss->ss_iflags |= ISCAN_START;
callout_reset(&ss->ss_scan_timer, delay, 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 ieee80211com *ic = ss->base.ss_ic;
int defer = 0;
if (ss->base.ss_next == ss->base.ss_last) {
IEEE80211_DPRINTF(ic, IEEE80211_MSG_SCAN,
"%s: no channels to scan\n", __func__);
return 0;
}
if (ic->ic_opmode == IEEE80211_M_STA &&
ic->ic_state == IEEE80211_S_RUN) {
if ((ic->ic_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 ieee80211com *ic, struct ieee80211_scan_state *ss,
int nssid, const struct ieee80211_scan_ssid ssids[])
{
if (nssid > IEEE80211_SCAN_MAX_SSID) {
/* XXX printf */
IEEE80211_DPRINTF(ic, 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.
*/
int
ieee80211_start_scan(struct ieee80211com *ic, int flags, u_int duration,
u_int nssid, const struct ieee80211_scan_ssid ssids[])
{
const struct ieee80211_scanner *scan;
struct ieee80211_scan_state *ss = ic->ic_scan;
scan = ieee80211_scanner_get(ic->ic_opmode);
if (scan == NULL) {
IEEE80211_DPRINTF(ic, IEEE80211_MSG_SCAN,
"%s: no scanner support for mode %u\n",
__func__, ic->ic_opmode);
/* XXX stat */
return 0;
}
IEEE80211_LOCK(ic);
if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) {
IEEE80211_DPRINTF(ic, IEEE80211_MSG_SCAN,
"%s: %s scan, duration %u, desired mode %s, %s%s%s%s\n"
, __func__
, flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive"
, duration
, ieee80211_phymode_name[ic->ic_des_mode]
, flags & IEEE80211_SCAN_FLUSH ? "flush" : "append"
, flags & IEEE80211_SCAN_NOPICK ? ", nopick" : ""
, flags & IEEE80211_SCAN_PICK1ST ? ", pick1st" : ""
, flags & IEEE80211_SCAN_ONCE ? ", once" : ""
);
ss->ss_ic = ic;
if (ss->ss_ops != scan) {
/* switch scanners; detach old, attach new */
if (ss->ss_ops != NULL)
ss->ss_ops->scan_detach(ss);
if (!scan->scan_attach(ss)) {
/* XXX attach failure */
/* XXX stat+msg */
ss->ss_ops = NULL;
} else
ss->ss_ops = scan;
}
if (ss->ss_ops != NULL) {
if ((flags & IEEE80211_SCAN_NOSSID) == 0)
copy_ssid(ic, ss, nssid, ssids);
/* NB: top 4 bits for internal use */
ss->ss_flags = flags & 0xfff;
if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
ic->ic_stats.is_scan_active++;
else
ic->ic_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_ops->scan_start(ss, ic);
if (scan_restart(SCAN_PRIVATE(ss), duration))
ic->ic_flags |= IEEE80211_F_SCAN;
}
} else {
IEEE80211_DPRINTF(ic, 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);
}
/*
* Check the scan cache for an ap/channel to use; if that
* fails then kick off a new scan.
*/
int
ieee80211_check_scan(struct ieee80211com *ic, int flags, u_int duration,
u_int nssid, const struct ieee80211_scan_ssid ssids[])
{
struct ieee80211_scan_state *ss = ic->ic_scan;
int checkscanlist = 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(ic, IEEE80211_MSG_SCAN,
"%s: %s scan, duration %u, desired mode %s, %s%s%s%s\n"
, __func__
, flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive"
, duration
, ieee80211_phymode_name[ic->ic_des_mode]
, flags & IEEE80211_SCAN_FLUSH ? "flush" : "append"
, flags & IEEE80211_SCAN_NOPICK ? ", nopick" : ""
, flags & IEEE80211_SCAN_PICK1ST ? ", pick1st" : ""
, flags & IEEE80211_SCAN_ONCE ? ", once" : ""
);
if (ss->ss_ops != NULL) {
/* XXX verify ss_ops matches ic->ic_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(ic, ss, nssid, ssids);
flags |= IEEE80211_SCAN_NOSSID;
}
if ((ic->ic_flags & IEEE80211_F_SCAN) == 0 &&
time_before(ticks, ic->ic_lastscan + ic->ic_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;
checkscanlist = 1;
}
}
IEEE80211_UNLOCK(ic);
if (checkscanlist) {
const struct ieee80211_scanner *scan;
scan = ieee80211_scanner_get(ic->ic_opmode);
if (scan == NULL) {
IEEE80211_DPRINTF(ic, IEEE80211_MSG_SCAN,
"%s: no scanner support for mode %u\n",
__func__, ic->ic_opmode);
/* XXX stat */
return 0;
}
if (scan == ss->ss_ops && ss->ss_ops->scan_end(ss, ic)) {
/* found an ap, just clear the flag */
ic->ic_flags &= ~IEEE80211_F_SCAN;
return 1;
}
/* no ap, clear the flag before starting a scan */
ic->ic_flags &= ~IEEE80211_F_SCAN;
}
return ieee80211_start_scan(ic, flags, duration, nssid, ssids);
}
/*
* Restart a previous scan. If the previous scan completed
* then we start again using the existing channel list.
*/
int
ieee80211_bg_scan(struct ieee80211com *ic)
{
struct ieee80211_scan_state *ss = ic->ic_scan;
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(ic, IEEE80211_MSG_SCAN,
"%s: %s scan, ticks %u duration %lu\n", __func__,
ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive",
ticks, duration);
if (ss->ss_ops != NULL) {
ss->ss_ic = ic;
/*
* 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;
/* if previous scan completed, restart */
if (ss->ss_next >= ss->ss_last) {
ss->ss_next = 0;
if (ss->ss_flags & IEEE80211_SCAN_ACTIVE)
ic->ic_stats.is_scan_active++;
else
ic->ic_stats.is_scan_passive++;
ss->ss_ops->scan_restart(ss, ic);
}
/* 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(ic, 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.
*/
void
ieee80211_cancel_scan(struct ieee80211com *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(ic, 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 ieee80211com *ic)
{
/*
* XXX: We might need/want to decouple context here by either:
* callout_reset(&SCAN_PRIVATE(ss)->ss_scan_timer, 0, scan_next, ss);
* or using a taskqueue. Let's see what kind of problems direct
* dispatch has for now.
*/
scan_next(ic->ic_scan);
}
/*
* 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 ieee80211com *ic, unsigned long maxdwell)
{
struct ieee80211_scan_state *ss = ic->ic_scan;
if ((ss->ss_flags & IEEE80211_SCAN_ACTIVE) &&
(ic->ic_curchan->ic_flags & IEEE80211_CHAN_PASSIVE) == 0) {
struct ifnet *ifp = ic->ic_ifp;
int i;
/*
* Send a broadcast probe request followed by
* any specified directed probe requests.
* XXX suppress broadcast probe req?
* XXX remove dependence on ic/ic->ic_bss
* XXX move to policy code?
*/
ieee80211_send_probereq(ic->ic_bss,
ic->ic_myaddr, ifp->if_broadcastaddr,
ifp->if_broadcastaddr,
"", 0,
ic->ic_opt_ie, ic->ic_opt_ie_len);
for (i = 0; i < ss->ss_nssid; i++)
ieee80211_send_probereq(ic->ic_bss,
ic->ic_myaddr, ifp->if_broadcastaddr,
ifp->if_broadcastaddr,
ss->ss_ssid[i].ssid,
ss->ss_ssid[i].len,
ic->ic_opt_ie, ic->ic_opt_ie_len);
}
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 ieee80211com *ic)
{
struct ieee80211_scan_state *ss = ic->ic_scan;
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 ieee80211com *ic = ss->ss_ic;
struct ieee80211_channel *chan;
unsigned long maxdwell, scanend;
int scanning, scandone;
IEEE80211_LOCK(ic);
scanning = (ic->ic_flags & IEEE80211_F_SCAN) != 0;
IEEE80211_UNLOCK(ic);
if (!scanning) /* canceled */
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(ic, 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(ic, 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)
change_channel(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, ic) &&
(ss->ss_flags & IEEE80211_SCAN_ONCE) == 0 &&
time_before(ticks + ss->ss_mindwell, scanend)) {
IEEE80211_DPRINTF(ic, 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)
ic->ic_stats.is_scan_active++;
else
ic->ic_stats.is_scan_passive++;
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(ic, 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(ic, 0);
if (ss->ss_next >= ss->ss_last) {
ieee80211_notify_scan_done(ic);
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_probe_beacon(uint8_t subtype, int isnew,
const uint8_t mac[IEEE80211_ADDR_LEN],
const struct ieee80211_scanparams *sp)
{
printf("[%s] %s%s on chan %u (bss chan %u) ",
ether_sprintf(mac), isnew ? "new " : "",
ieee80211_mgt_subtype_name[subtype >> IEEE80211_FC0_SUBTYPE_SHIFT],
IEEE80211_CHAN2IEEE(sp->curchan), sp->bchan);
Update 802.11 wireless support: o major overhaul of the way channels are handled: channels are now fully enumerated and uniquely identify the operating characteristics; these changes are visible to user applications which require changes o make scanning support independent of the state machine to enable background scanning and roaming o move scanning support into loadable modules based on the operating mode to enable different policies and reduce the memory footprint on systems w/ constrained resources o add background scanning in station mode (no support for adhoc/ibss mode yet) o significantly speedup sta mode scanning with a variety of techniques o add roaming support when background scanning is supported; for now we use a simple algorithm to trigger a roam: we threshold the rssi and tx rate, if either drops too low we try to roam to a new ap o add tx fragmentation support o add first cut at 802.11n support: this code works with forthcoming drivers but is incomplete; it's included now to establish a baseline for other drivers to be developed and for user applications o adjust max_linkhdr et. al. to reflect 802.11 requirements; this eliminates prepending mbufs for traffic generated locally o add support for Atheros protocol extensions; mainly the fast frames encapsulation (note this can be used with any card that can tx+rx large frames correctly) o add sta support for ap's that beacon both WPA1+2 support o change all data types from bsd-style to posix-style o propagate noise floor data from drivers to net80211 and on to user apps o correct various issues in the sta mode state machine related to handling authentication and association failures o enable the addition of sta mode power save support for drivers that need net80211 support (not in this commit) o remove old WI compatibility ioctls (wicontrol is officially dead) o change the data structures returned for get sta info and get scan results so future additions will not break user apps o fixed tx rate is now maintained internally as an ieee rate and not an index into the rate set; this needs to be extended to deal with multi-mode operation o add extended channel specifications to radiotap to enable 11n sniffing Drivers: o ath: add support for bg scanning, tx fragmentation, fast frames, dynamic turbo (lightly tested), 11n (sniffing only and needs new hal) o awi: compile tested only o ndis: lightly tested o ipw: lightly tested o iwi: add support for bg scanning (well tested but may have some rough edges) o ral, ural, rum: add suppoort for bg scanning, calibrate rssi data o wi: lightly tested This work is based on contributions by Atheros, kmacy, sephe, thompsa, mlaier, kevlo, and others. Much of the scanning work was supported by Atheros. The 11n work was supported by Marvell.
2007-06-11 03:36:55 +00:00
ieee80211_print_essid(sp->ssid + 2, sp->ssid[1]);
printf("\n");
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) {
#ifdef __FreeBSD__
printf(" country info %*D",
sp->country[1], sp->country+2, " ");
#else
int i;
printf(" country info");
for (i = 0; i < sp->country[1]; i++)
printf(" %02x", sp->country[i+2]);
#endif
}
printf("\n");
}
}
#endif /* IEEE80211_DEBUG */
/*
* Process a beacon or probe response frame.
*/
void
ieee80211_add_scan(struct ieee80211com *ic,
const struct ieee80211_scanparams *sp,
const struct ieee80211_frame *wh,
int subtype, int rssi, int noise, int rstamp)
{
struct ieee80211_scan_state *ss = ic->ic_scan;
/*
* 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 (we defer the channel change to the timer
* code to simplify locking on linux).
*/
if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_DISCARD)
return;
#ifdef IEEE80211_DEBUG
if (ieee80211_msg_scan(ic) && (ic->ic_flags & IEEE80211_F_SCAN))
dump_probe_beacon(subtype, 1, wh->i_addr2, sp);
#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(ic, 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);
/*
* XXX
* We want to just kick the timer and still
* process frames until it fires but linux
* will livelock unless we discard frames.
*/
#if 0
SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_MINDWELL;
#else
SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD;
#endif
/*
* NB: trigger at next clock tick or wait for the
* hardware
*/
ic->ic_scan_mindwell(ic);
}
}
}
/*
* 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 ieee80211com *ic, const uint8_t mac[])
{
struct ieee80211_scan_state *ss = ic->ic_scan;
if (ss->ss_ops != NULL) {
IEEE80211_NOTE_MAC(ic, 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 ieee80211com *ic,
const uint8_t mac[], int reason)
{
struct ieee80211_scan_state *ss = ic->ic_scan;
if (ss->ss_ops != NULL) {
IEEE80211_NOTE_MAC(ic, 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 ieee80211com *ic,
ieee80211_scan_iter_func *f, void *arg)
{
struct ieee80211_scan_state *ss = 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 ieee80211com *ic)
{
struct ieee80211_scan_state *ss = ic->ic_scan;
if (ss->ss_ops != NULL) {
IEEE80211_DPRINTF(ic, IEEE80211_MSG_SCAN,
"%s\n", __func__);
ss->ss_ops->scan_flush(ss);
}
}