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linux-next/net/mac80211/scan.c

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/*
* Scanning implementation
*
* Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
* Copyright 2004, Instant802 Networks, Inc.
* Copyright 2005, Devicescape Software, Inc.
* Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
* Copyright 2007, Michael Wu <flamingice@sourmilk.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/if_arp.h>
#include <linux/rtnetlink.h>
#include <linux/pm_qos_params.h>
#include <net/sch_generic.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 16:04:11 +08:00
#include <linux/slab.h>
#include <net/mac80211.h>
#include "ieee80211_i.h"
#include "driver-ops.h"
#include "mesh.h"
#define IEEE80211_PROBE_DELAY (HZ / 33)
#define IEEE80211_CHANNEL_TIME (HZ / 33)
#define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 8)
struct ieee80211_bss *
ieee80211_rx_bss_get(struct ieee80211_local *local, u8 *bssid, int freq,
u8 *ssid, u8 ssid_len)
{
struct cfg80211_bss *cbss;
cbss = cfg80211_get_bss(local->hw.wiphy,
ieee80211_get_channel(local->hw.wiphy, freq),
bssid, ssid, ssid_len, 0, 0);
if (!cbss)
return NULL;
return (void *)cbss->priv;
}
static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss)
{
struct ieee80211_bss *bss = (void *)cbss->priv;
kfree(bss_mesh_id(bss));
kfree(bss_mesh_cfg(bss));
}
void ieee80211_rx_bss_put(struct ieee80211_local *local,
struct ieee80211_bss *bss)
{
if (!bss)
return;
cfg80211_put_bss(container_of((void *)bss, struct cfg80211_bss, priv));
}
static bool is_uapsd_supported(struct ieee802_11_elems *elems)
{
u8 qos_info;
if (elems->wmm_info && elems->wmm_info_len == 7
&& elems->wmm_info[5] == 1)
qos_info = elems->wmm_info[6];
else if (elems->wmm_param && elems->wmm_param_len == 24
&& elems->wmm_param[5] == 1)
qos_info = elems->wmm_param[6];
else
/* no valid wmm information or parameter element found */
return false;
return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
}
struct ieee80211_bss *
ieee80211_bss_info_update(struct ieee80211_local *local,
struct ieee80211_rx_status *rx_status,
struct ieee80211_mgmt *mgmt,
size_t len,
struct ieee802_11_elems *elems,
struct ieee80211_channel *channel,
bool beacon)
{
struct cfg80211_bss *cbss;
struct ieee80211_bss *bss;
int clen, srlen;
s32 signal = 0;
if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
signal = rx_status->signal * 100;
else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
signal = (rx_status->signal * 100) / local->hw.max_signal;
cbss = cfg80211_inform_bss_frame(local->hw.wiphy, channel,
mgmt, len, signal, GFP_ATOMIC);
if (!cbss)
return NULL;
cbss->free_priv = ieee80211_rx_bss_free;
bss = (void *)cbss->priv;
/* save the ERP value so that it is available at association time */
if (elems->erp_info && elems->erp_info_len >= 1) {
bss->erp_value = elems->erp_info[0];
bss->has_erp_value = 1;
}
if (elems->tim) {
struct ieee80211_tim_ie *tim_ie =
(struct ieee80211_tim_ie *)elems->tim;
bss->dtim_period = tim_ie->dtim_period;
}
/* replace old supported rates if we get new values */
srlen = 0;
if (elems->supp_rates) {
clen = IEEE80211_MAX_SUPP_RATES;
if (clen > elems->supp_rates_len)
clen = elems->supp_rates_len;
memcpy(bss->supp_rates, elems->supp_rates, clen);
srlen += clen;
}
if (elems->ext_supp_rates) {
clen = IEEE80211_MAX_SUPP_RATES - srlen;
if (clen > elems->ext_supp_rates_len)
clen = elems->ext_supp_rates_len;
memcpy(bss->supp_rates + srlen, elems->ext_supp_rates, clen);
srlen += clen;
}
if (srlen)
bss->supp_rates_len = srlen;
bss->wmm_used = elems->wmm_param || elems->wmm_info;
bss->uapsd_supported = is_uapsd_supported(elems);
if (!beacon)
bss->last_probe_resp = jiffies;
return bss;
}
ieee80211_rx_result
ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
{
struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
struct ieee80211_mgmt *mgmt;
struct ieee80211_bss *bss;
u8 *elements;
struct ieee80211_channel *channel;
size_t baselen;
int freq;
__le16 fc;
bool presp, beacon = false;
struct ieee802_11_elems elems;
if (skb->len < 2)
return RX_DROP_UNUSABLE;
mgmt = (struct ieee80211_mgmt *) skb->data;
fc = mgmt->frame_control;
if (ieee80211_is_ctl(fc))
return RX_CONTINUE;
if (skb->len < 24)
return RX_DROP_MONITOR;
presp = ieee80211_is_probe_resp(fc);
if (presp) {
/* ignore ProbeResp to foreign address */
if (memcmp(mgmt->da, sdata->vif.addr, ETH_ALEN))
return RX_DROP_MONITOR;
presp = true;
elements = mgmt->u.probe_resp.variable;
baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
} else {
beacon = ieee80211_is_beacon(fc);
baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
elements = mgmt->u.beacon.variable;
}
if (!presp && !beacon)
return RX_CONTINUE;
if (baselen > skb->len)
return RX_DROP_MONITOR;
ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
if (elems.ds_params && elems.ds_params_len == 1)
freq = ieee80211_channel_to_frequency(elems.ds_params[0]);
else
freq = rx_status->freq;
channel = ieee80211_get_channel(sdata->local->hw.wiphy, freq);
if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
return RX_DROP_MONITOR;
bss = ieee80211_bss_info_update(sdata->local, rx_status,
mgmt, skb->len, &elems,
channel, beacon);
if (bss)
ieee80211_rx_bss_put(sdata->local, bss);
dev_kfree_skb(skb);
return RX_QUEUED;
}
/* return false if no more work */
static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
{
struct cfg80211_scan_request *req = local->scan_req;
enum ieee80211_band band;
int i, ielen, n_chans;
do {
if (local->hw_scan_band == IEEE80211_NUM_BANDS)
return false;
band = local->hw_scan_band;
n_chans = 0;
for (i = 0; i < req->n_channels; i++) {
if (req->channels[i]->band == band) {
local->hw_scan_req->channels[n_chans] =
req->channels[i];
n_chans++;
}
}
local->hw_scan_band++;
} while (!n_chans);
local->hw_scan_req->n_channels = n_chans;
ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
req->ie, req->ie_len, band);
local->hw_scan_req->ie_len = ielen;
return true;
}
void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
{
struct ieee80211_local *local = hw_to_local(hw);
bool was_hw_scan;
trace_api_scan_completed(local, aborted);
mutex_lock(&local->scan_mtx);
/*
* It's ok to abort a not-yet-running scan (that
* we have one at all will be verified by checking
* local->scan_req next), but not to complete it
* successfully.
*/
if (WARN_ON(!local->scanning && !aborted))
aborted = true;
if (WARN_ON(!local->scan_req)) {
mutex_unlock(&local->scan_mtx);
return;
}
was_hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
ieee80211_queue_delayed_work(&local->hw,
&local->scan_work, 0);
mutex_unlock(&local->scan_mtx);
return;
}
kfree(local->hw_scan_req);
local->hw_scan_req = NULL;
if (local->scan_req != local->int_scan_req)
cfg80211_scan_done(local->scan_req, aborted);
local->scan_req = NULL;
local->scan_sdata = NULL;
local->scanning = 0;
mac80211: fix scan channel race When a software scan starts, it first sets sw_scanning, but leaves the scan_channel "unset" (it currently actually gets initialised to a default). Now, when something else tries to (re)configure the hardware in the window between these two events (after sw_scanning = true, but before scan_channel is set), the current code switches to the (unset!) scan_channel. This causes trouble, especially when switching bands and sending frames on the wrong channel. To work around this, leave scan_channel initialised to NULL and use it to determine whether or not a switch to a different channel should occur (and also use the same condition to check whether to adjust power for scan or not). Additionally, avoid reconfiguring the hardware completely when recalculating idle resulted in no changes, this was the problem that originally led us to discover the race condition in the first place, which was helpfully bisected by Pavel. This part of the patch should not be necessary with the other fixes, but not calling the ieee80211_hw_config function when we know it to be unnecessary is certainly a correct thing to do. Unfortunately, this patch cannot and does not fix the race condition completely, but due to the way the scan code is structured it makes the particular problem Pavel discovered (race while changing channel at the same time as transmitting frames) go away. To fix it completely, more work especially with locking configuration is needed. Bisected-by: Pavel Roskin <proski@gnu.org> Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-05-07 20:23:01 +08:00
local->scan_channel = NULL;
/* we only have to protect scan_req and hw/sw scan */
mutex_unlock(&local->scan_mtx);
ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
mac80211: tell driver when idle When we aren't doing anything in mac80211, we can turn off much of the hardware, depending on the driver/hw. Not doing anything, aka being idle, means: * no monitor interfaces * no AP/mesh/wds interfaces * any station interfaces are in DISABLED state * any IBSS interfaces aren't trying to be in a network * we aren't trying to scan By creating a new function that verifies these conditions and calling it at strategic points where the states of those conditions change, we can easily make mac80211 tell the driver when we are idle to save power. Additionally, this fixes a small quirk where a recalculated powersave state is passed to the driver even if the hardware is about to stopped completely. This patch intentionally doesn't touch radio_enabled because that is currently implemented to be a soft rfkill which is inappropriate here when we need to be able to wake up with low latency. One thing I'm not entirely sure about is this: phy0: device no longer idle - in use wlan0: direct probe to AP 00:11:24:91:07:4d try 1 wlan0 direct probe responded wlan0: authenticate with AP 00:11:24:91:07:4d wlan0: authenticated > phy0: device now idle > phy0: device no longer idle - in use wlan0: associate with AP 00:11:24:91:07:4d wlan0: RX AssocResp from 00:11:24:91:07:4d (capab=0x401 status=0 aid=1) wlan0: associated Is it appropriate to go into idle state for a short time when we have just authenticated, but not associated yet? This happens only with the userspace SME, because we cannot really know how long it will wait before asking us to associate. Would going idle after a short timeout be more appropriate? We may need to revisit this, depending on what happens. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-04-29 18:26:17 +08:00
if (was_hw_scan)
goto done;
ieee80211_configure_filter(local);
drv_sw_scan_complete(local);
ieee80211_offchannel_return(local, true);
done:
mac80211: tell driver when idle When we aren't doing anything in mac80211, we can turn off much of the hardware, depending on the driver/hw. Not doing anything, aka being idle, means: * no monitor interfaces * no AP/mesh/wds interfaces * any station interfaces are in DISABLED state * any IBSS interfaces aren't trying to be in a network * we aren't trying to scan By creating a new function that verifies these conditions and calling it at strategic points where the states of those conditions change, we can easily make mac80211 tell the driver when we are idle to save power. Additionally, this fixes a small quirk where a recalculated powersave state is passed to the driver even if the hardware is about to stopped completely. This patch intentionally doesn't touch radio_enabled because that is currently implemented to be a soft rfkill which is inappropriate here when we need to be able to wake up with low latency. One thing I'm not entirely sure about is this: phy0: device no longer idle - in use wlan0: direct probe to AP 00:11:24:91:07:4d try 1 wlan0 direct probe responded wlan0: authenticate with AP 00:11:24:91:07:4d wlan0: authenticated > phy0: device now idle > phy0: device no longer idle - in use wlan0: associate with AP 00:11:24:91:07:4d wlan0: RX AssocResp from 00:11:24:91:07:4d (capab=0x401 status=0 aid=1) wlan0: associated Is it appropriate to go into idle state for a short time when we have just authenticated, but not associated yet? This happens only with the userspace SME, because we cannot really know how long it will wait before asking us to associate. Would going idle after a short timeout be more appropriate? We may need to revisit this, depending on what happens. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-04-29 18:26:17 +08:00
ieee80211_recalc_idle(local);
ieee80211_mlme_notify_scan_completed(local);
ieee80211_ibss_notify_scan_completed(local);
ieee80211_mesh_notify_scan_completed(local);
ieee80211_queue_work(&local->hw, &local->work_work);
}
EXPORT_SYMBOL(ieee80211_scan_completed);
static int ieee80211_start_sw_scan(struct ieee80211_local *local)
{
/*
* Hardware/driver doesn't support hw_scan, so use software
* scanning instead. First send a nullfunc frame with power save
* bit on so that AP will buffer the frames for us while we are not
* listening, then send probe requests to each channel and wait for
* the responses. After all channels are scanned, tune back to the
* original channel and send a nullfunc frame with power save bit
* off to trigger the AP to send us all the buffered frames.
*
* Note that while local->sw_scanning is true everything else but
* nullfunc frames and probe requests will be dropped in
* ieee80211_tx_h_check_assoc().
*/
drv_sw_scan_start(local);
ieee80211_offchannel_stop_beaconing(local);
local->leave_oper_channel_time = 0;
local->next_scan_state = SCAN_DECISION;
local->scan_channel_idx = 0;
drv_flush(local, false);
ieee80211_configure_filter(local);
ieee80211_queue_delayed_work(&local->hw,
&local->scan_work,
IEEE80211_CHANNEL_TIME);
return 0;
}
static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
struct cfg80211_scan_request *req)
{
struct ieee80211_local *local = sdata->local;
int rc;
if (local->scan_req)
return -EBUSY;
if (!list_empty(&local->work_list)) {
/* wait for the work to finish/time out */
local->scan_req = req;
local->scan_sdata = sdata;
return 0;
}
if (local->ops->hw_scan) {
u8 *ies;
local->hw_scan_req = kmalloc(
sizeof(*local->hw_scan_req) +
req->n_channels * sizeof(req->channels[0]) +
2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len +
req->ie_len, GFP_KERNEL);
if (!local->hw_scan_req)
return -ENOMEM;
local->hw_scan_req->ssids = req->ssids;
local->hw_scan_req->n_ssids = req->n_ssids;
ies = (u8 *)local->hw_scan_req +
sizeof(*local->hw_scan_req) +
req->n_channels * sizeof(req->channels[0]);
local->hw_scan_req->ie = ies;
local->hw_scan_band = 0;
/*
* After allocating local->hw_scan_req, we must
* go through until ieee80211_prep_hw_scan(), so
* anything that might be changed here and leave
* this function early must not go after this
* allocation.
*/
}
local->scan_req = req;
local->scan_sdata = sdata;
if (local->ops->hw_scan)
__set_bit(SCAN_HW_SCANNING, &local->scanning);
else
__set_bit(SCAN_SW_SCANNING, &local->scanning);
/*
* Kicking off the scan need not be protected,
* only the scan variable stuff, since now
* local->scan_req is assigned and other callers
* will abort their scan attempts.
*
* This avoids too many locking dependencies
* so that the scan completed calls have more
* locking freedom.
*/
mac80211: tell driver when idle When we aren't doing anything in mac80211, we can turn off much of the hardware, depending on the driver/hw. Not doing anything, aka being idle, means: * no monitor interfaces * no AP/mesh/wds interfaces * any station interfaces are in DISABLED state * any IBSS interfaces aren't trying to be in a network * we aren't trying to scan By creating a new function that verifies these conditions and calling it at strategic points where the states of those conditions change, we can easily make mac80211 tell the driver when we are idle to save power. Additionally, this fixes a small quirk where a recalculated powersave state is passed to the driver even if the hardware is about to stopped completely. This patch intentionally doesn't touch radio_enabled because that is currently implemented to be a soft rfkill which is inappropriate here when we need to be able to wake up with low latency. One thing I'm not entirely sure about is this: phy0: device no longer idle - in use wlan0: direct probe to AP 00:11:24:91:07:4d try 1 wlan0 direct probe responded wlan0: authenticate with AP 00:11:24:91:07:4d wlan0: authenticated > phy0: device now idle > phy0: device no longer idle - in use wlan0: associate with AP 00:11:24:91:07:4d wlan0: RX AssocResp from 00:11:24:91:07:4d (capab=0x401 status=0 aid=1) wlan0: associated Is it appropriate to go into idle state for a short time when we have just authenticated, but not associated yet? This happens only with the userspace SME, because we cannot really know how long it will wait before asking us to associate. Would going idle after a short timeout be more appropriate? We may need to revisit this, depending on what happens. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-04-29 18:26:17 +08:00
ieee80211_recalc_idle(local);
mutex_unlock(&local->scan_mtx);
if (local->ops->hw_scan) {
WARN_ON(!ieee80211_prep_hw_scan(local));
rc = drv_hw_scan(local, sdata, local->hw_scan_req);
} else
rc = ieee80211_start_sw_scan(local);
mutex_lock(&local->scan_mtx);
if (rc) {
kfree(local->hw_scan_req);
local->hw_scan_req = NULL;
local->scanning = 0;
mac80211: tell driver when idle When we aren't doing anything in mac80211, we can turn off much of the hardware, depending on the driver/hw. Not doing anything, aka being idle, means: * no monitor interfaces * no AP/mesh/wds interfaces * any station interfaces are in DISABLED state * any IBSS interfaces aren't trying to be in a network * we aren't trying to scan By creating a new function that verifies these conditions and calling it at strategic points where the states of those conditions change, we can easily make mac80211 tell the driver when we are idle to save power. Additionally, this fixes a small quirk where a recalculated powersave state is passed to the driver even if the hardware is about to stopped completely. This patch intentionally doesn't touch radio_enabled because that is currently implemented to be a soft rfkill which is inappropriate here when we need to be able to wake up with low latency. One thing I'm not entirely sure about is this: phy0: device no longer idle - in use wlan0: direct probe to AP 00:11:24:91:07:4d try 1 wlan0 direct probe responded wlan0: authenticate with AP 00:11:24:91:07:4d wlan0: authenticated > phy0: device now idle > phy0: device no longer idle - in use wlan0: associate with AP 00:11:24:91:07:4d wlan0: RX AssocResp from 00:11:24:91:07:4d (capab=0x401 status=0 aid=1) wlan0: associated Is it appropriate to go into idle state for a short time when we have just authenticated, but not associated yet? This happens only with the userspace SME, because we cannot really know how long it will wait before asking us to associate. Would going idle after a short timeout be more appropriate? We may need to revisit this, depending on what happens. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-04-29 18:26:17 +08:00
ieee80211_recalc_idle(local);
local->scan_req = NULL;
local->scan_sdata = NULL;
}
return rc;
}
static unsigned long
ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
{
/*
* TODO: channel switching also consumes quite some time,
* add that delay as well to get a better estimation
*/
if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
return IEEE80211_PASSIVE_CHANNEL_TIME;
return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
}
static int ieee80211_scan_state_decision(struct ieee80211_local *local,
unsigned long *next_delay)
{
bool associated = false;
bool tx_empty = true;
bool bad_latency;
bool listen_int_exceeded;
unsigned long min_beacon_int = 0;
struct ieee80211_sub_if_data *sdata;
struct ieee80211_channel *next_chan;
/* if no more bands/channels left, complete scan and advance to the idle state */
if (local->scan_channel_idx >= local->scan_req->n_channels) {
ieee80211_scan_completed(&local->hw, false);
return 1;
}
/*
* check if at least one STA interface is associated,
* check if at least one STA interface has pending tx frames
* and grab the lowest used beacon interval
*/
mutex_lock(&local->iflist_mtx);
list_for_each_entry(sdata, &local->interfaces, list) {
if (!ieee80211_sdata_running(sdata))
continue;
if (sdata->vif.type == NL80211_IFTYPE_STATION) {
if (sdata->u.mgd.associated) {
associated = true;
if (sdata->vif.bss_conf.beacon_int <
min_beacon_int || min_beacon_int == 0)
min_beacon_int =
sdata->vif.bss_conf.beacon_int;
if (!qdisc_all_tx_empty(sdata->dev)) {
tx_empty = false;
break;
}
}
}
}
mutex_unlock(&local->iflist_mtx);
if (local->scan_channel) {
/*
* we're currently scanning a different channel, let's
* see if we can scan another channel without interfering
* with the current traffic situation.
*
* Since we don't know if the AP has pending frames for us
* we can only check for our tx queues and use the current
* pm_qos requirements for rx. Hence, if no tx traffic occurs
* at all we will scan as many channels in a row as the pm_qos
* latency allows us to. Additionally we also check for the
* currently negotiated listen interval to prevent losing
* frames unnecessarily.
*
* Otherwise switch back to the operating channel.
*/
next_chan = local->scan_req->channels[local->scan_channel_idx];
bad_latency = time_after(jiffies +
ieee80211_scan_get_channel_time(next_chan),
local->leave_oper_channel_time +
2010-05-21 12:04:44 +08:00
usecs_to_jiffies(pm_qos_request(PM_QOS_NETWORK_LATENCY)));
listen_int_exceeded = time_after(jiffies +
ieee80211_scan_get_channel_time(next_chan),
local->leave_oper_channel_time +
usecs_to_jiffies(min_beacon_int * 1024) *
local->hw.conf.listen_interval);
if (associated && ( !tx_empty || bad_latency ||
listen_int_exceeded))
local->next_scan_state = SCAN_ENTER_OPER_CHANNEL;
else
local->next_scan_state = SCAN_SET_CHANNEL;
} else {
/*
* we're on the operating channel currently, let's
* leave that channel now to scan another one
*/
local->next_scan_state = SCAN_LEAVE_OPER_CHANNEL;
}
*next_delay = 0;
return 0;
}
static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *local,
unsigned long *next_delay)
{
ieee80211_offchannel_stop_station(local);
__set_bit(SCAN_OFF_CHANNEL, &local->scanning);
/*
* What if the nullfunc frames didn't arrive?
*/
drv_flush(local, false);
if (local->ops->flush)
*next_delay = 0;
else
*next_delay = HZ / 10;
/* remember when we left the operating channel */
local->leave_oper_channel_time = jiffies;
/* advance to the next channel to be scanned */
local->next_scan_state = SCAN_SET_CHANNEL;
}
static void ieee80211_scan_state_enter_oper_channel(struct ieee80211_local *local,
unsigned long *next_delay)
{
/* switch back to the operating channel */
local->scan_channel = NULL;
ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
/*
* Only re-enable station mode interface now; beaconing will be
* re-enabled once the full scan has been completed.
*/
ieee80211_offchannel_return(local, false);
__clear_bit(SCAN_OFF_CHANNEL, &local->scanning);
*next_delay = HZ / 5;
local->next_scan_state = SCAN_DECISION;
}
static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
unsigned long *next_delay)
{
int skip;
struct ieee80211_channel *chan;
skip = 0;
chan = local->scan_req->channels[local->scan_channel_idx];
local->scan_channel = chan;
if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
skip = 1;
/* advance state machine to next channel/band */
local->scan_channel_idx++;
if (skip) {
/* if we skip this channel return to the decision state */
local->next_scan_state = SCAN_DECISION;
return;
}
/*
* Probe delay is used to update the NAV, cf. 11.1.3.2.2
* (which unfortunately doesn't say _why_ step a) is done,
* but it waits for the probe delay or until a frame is
* received - and the received frame would update the NAV).
* For now, we do not support waiting until a frame is
* received.
*
* In any case, it is not necessary for a passive scan.
*/
if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
!local->scan_req->n_ssids) {
*next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
local->next_scan_state = SCAN_DECISION;
return;
}
/* active scan, send probes */
*next_delay = IEEE80211_PROBE_DELAY;
local->next_scan_state = SCAN_SEND_PROBE;
}
static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
unsigned long *next_delay)
{
int i;
struct ieee80211_sub_if_data *sdata = local->scan_sdata;
for (i = 0; i < local->scan_req->n_ssids; i++)
ieee80211_send_probe_req(
sdata, NULL,
local->scan_req->ssids[i].ssid,
local->scan_req->ssids[i].ssid_len,
local->scan_req->ie, local->scan_req->ie_len);
/*
* After sending probe requests, wait for probe responses
* on the channel.
*/
*next_delay = IEEE80211_CHANNEL_TIME;
local->next_scan_state = SCAN_DECISION;
}
void ieee80211_scan_work(struct work_struct *work)
{
struct ieee80211_local *local =
container_of(work, struct ieee80211_local, scan_work.work);
struct ieee80211_sub_if_data *sdata = local->scan_sdata;
unsigned long next_delay = 0;
mutex_lock(&local->scan_mtx);
if (!sdata || !local->scan_req) {
mutex_unlock(&local->scan_mtx);
return;
}
if (local->hw_scan_req) {
int rc = drv_hw_scan(local, sdata, local->hw_scan_req);
mutex_unlock(&local->scan_mtx);
if (rc)
ieee80211_scan_completed(&local->hw, true);
return;
}
if (local->scan_req && !local->scanning) {
struct cfg80211_scan_request *req = local->scan_req;
int rc;
local->scan_req = NULL;
local->scan_sdata = NULL;
rc = __ieee80211_start_scan(sdata, req);
mutex_unlock(&local->scan_mtx);
if (rc)
ieee80211_scan_completed(&local->hw, true);
return;
}
mutex_unlock(&local->scan_mtx);
/*
* Avoid re-scheduling when the sdata is going away.
*/
if (!ieee80211_sdata_running(sdata)) {
ieee80211_scan_completed(&local->hw, true);
return;
}
/*
* as long as no delay is required advance immediately
* without scheduling a new work
*/
do {
switch (local->next_scan_state) {
case SCAN_DECISION:
if (ieee80211_scan_state_decision(local, &next_delay))
return;
break;
case SCAN_SET_CHANNEL:
ieee80211_scan_state_set_channel(local, &next_delay);
break;
case SCAN_SEND_PROBE:
ieee80211_scan_state_send_probe(local, &next_delay);
break;
case SCAN_LEAVE_OPER_CHANNEL:
ieee80211_scan_state_leave_oper_channel(local, &next_delay);
break;
case SCAN_ENTER_OPER_CHANNEL:
ieee80211_scan_state_enter_oper_channel(local, &next_delay);
break;
}
} while (next_delay == 0);
ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
}
int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
struct cfg80211_scan_request *req)
{
int res;
mutex_lock(&sdata->local->scan_mtx);
res = __ieee80211_start_scan(sdata, req);
mutex_unlock(&sdata->local->scan_mtx);
return res;
}
int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
const u8 *ssid, u8 ssid_len,
struct ieee80211_channel *chan)
{
struct ieee80211_local *local = sdata->local;
int ret = -EBUSY;
enum ieee80211_band band;
mutex_lock(&local->scan_mtx);
/* busy scanning */
if (local->scan_req)
goto unlock;
/* fill internal scan request */
if (!chan) {
int i, nchan = 0;
for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
if (!local->hw.wiphy->bands[band])
continue;
for (i = 0;
i < local->hw.wiphy->bands[band]->n_channels;
i++) {
local->int_scan_req->channels[nchan] =
&local->hw.wiphy->bands[band]->channels[i];
nchan++;
}
}
local->int_scan_req->n_channels = nchan;
} else {
local->int_scan_req->channels[0] = chan;
local->int_scan_req->n_channels = 1;
}
local->int_scan_req->ssids = &local->scan_ssid;
local->int_scan_req->n_ssids = 1;
memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
local->int_scan_req->ssids[0].ssid_len = ssid_len;
ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
unlock:
mutex_unlock(&local->scan_mtx);
return ret;
}
void ieee80211_scan_cancel(struct ieee80211_local *local)
{
bool abortscan;
cancel_delayed_work_sync(&local->scan_work);
/*
* Only call this function when a scan can't be
* queued -- mostly at suspend under RTNL.
*/
mutex_lock(&local->scan_mtx);
abortscan = test_bit(SCAN_SW_SCANNING, &local->scanning) ||
(!local->scanning && local->scan_req);
mutex_unlock(&local->scan_mtx);
if (abortscan)
ieee80211_scan_completed(&local->hw, true);
}