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scan.c
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/*
* Scanning implementation
*
* Copyright 2003, Jouni Malinen <[email protected]>
* Copyright 2004, Instant802 Networks, Inc.
* Copyright 2005, Devicescape Software, Inc.
* Copyright 2006-2007 Jiri Benc <[email protected]>
* Copyright 2007, Michael Wu <[email protected]>
* Copyright 2013-2015 Intel Mobile Communications GmbH
*
* 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/etherdevice.h>
#include <linux/rtnetlink.h>
#include <net/sch_generic.h>
#include <linux/slab.h>
#include <linux/export.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 / 9)
void ieee80211_rx_bss_put(struct ieee80211_local *local,
struct ieee80211_bss *bss)
{
if (!bss)
return;
cfg80211_put_bss(local->hw.wiphy,
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 = ieee80211_is_beacon(mgmt->frame_control);
struct cfg80211_bss *cbss;
struct ieee80211_bss *bss;
int clen, srlen;
struct cfg80211_inform_bss bss_meta = {};
bool signal_valid;
if (ieee80211_hw_check(&local->hw, SIGNAL_DBM))
bss_meta.signal = rx_status->signal * 100;
else if (ieee80211_hw_check(&local->hw, SIGNAL_UNSPEC))
bss_meta.signal = (rx_status->signal * 100) / local->hw.max_signal;
bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_20;
if (rx_status->flag & RX_FLAG_5MHZ)
bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_5;
if (rx_status->flag & RX_FLAG_10MHZ)
bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_10;
bss_meta.chan = channel;
cbss = cfg80211_inform_bss_frame_data(local->hw.wiphy, &bss_meta,
mgmt, len, GFP_ATOMIC);
if (!cbss)
return NULL;
/* In case the signal is invalid update the status */
signal_valid = abs(channel->center_freq - cbss->channel->center_freq)
<= local->hw.wiphy->max_adj_channel_rssi_comp;
if (!signal_valid)
rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL;
bss = (void *)cbss->priv;
if (beacon)
bss->device_ts_beacon = rx_status->device_timestamp;
else
bss->device_ts_presp = rx_status->device_timestamp;
if (elems->parse_error) {
if (beacon)
bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
else
bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
} else {
if (beacon)
bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
else
bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
}
/* save the ERP value so that it is available at association time */
if (elems->erp_info && (!elems->parse_error ||
!(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
bss->erp_value = elems->erp_info[0];
bss->has_erp_value = true;
if (!elems->parse_error)
bss->valid_data |= IEEE80211_BSS_VALID_ERP;
}
/* replace old supported rates if we get new values */
if (!elems->parse_error ||
!(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
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;
if (!elems->parse_error)
bss->valid_data |= IEEE80211_BSS_VALID_RATES;
}
}
if (!elems->parse_error ||
!(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
bss->wmm_used = elems->wmm_param || elems->wmm_info;
bss->uapsd_supported = is_uapsd_supported(elems);
if (!elems->parse_error)
bss->valid_data |= IEEE80211_BSS_VALID_WMM;
}
if (beacon) {
struct ieee80211_supported_band *sband =
local->hw.wiphy->bands[rx_status->band];
if (!(rx_status->flag & RX_FLAG_HT) &&
!(rx_status->flag & RX_FLAG_VHT))
bss->beacon_rate =
&sband->bitrates[rx_status->rate_idx];
}
return bss;
}
void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
{
struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
struct ieee80211_sub_if_data *sdata1, *sdata2;
struct ieee80211_mgmt *mgmt = (void *)skb->data;
struct ieee80211_bss *bss;
u8 *elements;
struct ieee80211_channel *channel;
size_t baselen;
struct ieee802_11_elems elems;
if (skb->len < 24 ||
(!ieee80211_is_probe_resp(mgmt->frame_control) &&
!ieee80211_is_beacon(mgmt->frame_control)))
return;
sdata1 = rcu_dereference(local->scan_sdata);
sdata2 = rcu_dereference(local->sched_scan_sdata);
if (likely(!sdata1 && !sdata2))
return;
if (ieee80211_is_probe_resp(mgmt->frame_control)) {
struct cfg80211_scan_request *scan_req;
struct cfg80211_sched_scan_request *sched_scan_req;
scan_req = rcu_dereference(local->scan_req);
sched_scan_req = rcu_dereference(local->sched_scan_req);
/* ignore ProbeResp to foreign address unless scanning
* with randomised address
*/
if (!(sdata1 &&
(ether_addr_equal(mgmt->da, sdata1->vif.addr) ||
scan_req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)) &&
!(sdata2 &&
(ether_addr_equal(mgmt->da, sdata2->vif.addr) ||
sched_scan_req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)))
return;
elements = mgmt->u.probe_resp.variable;
baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
} else {
baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
elements = mgmt->u.beacon.variable;
}
if (baselen > skb->len)
return;
ieee802_11_parse_elems(elements, skb->len - baselen, false, &elems);
channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
return;
bss = ieee80211_bss_info_update(local, rx_status,
mgmt, skb->len, &elems,
channel);
if (bss)
ieee80211_rx_bss_put(local, bss);
}
static void
ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
enum nl80211_bss_scan_width scan_width)
{
memset(chandef, 0, sizeof(*chandef));
switch (scan_width) {
case NL80211_BSS_CHAN_WIDTH_5:
chandef->width = NL80211_CHAN_WIDTH_5;
break;
case NL80211_BSS_CHAN_WIDTH_10:
chandef->width = NL80211_CHAN_WIDTH_10;
break;
default:
chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
break;
}
}
/* return false if no more work */
static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
{
struct cfg80211_scan_request *req;
struct cfg80211_chan_def chandef;
u8 bands_used = 0;
int i, ielen, n_chans;
req = rcu_dereference_protected(local->scan_req,
lockdep_is_held(&local->mtx));
if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
return false;
if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
for (i = 0; i < req->n_channels; i++) {
local->hw_scan_req->req.channels[i] = req->channels[i];
bands_used |= BIT(req->channels[i]->band);
}
n_chans = req->n_channels;
} else {
do {
if (local->hw_scan_band == IEEE80211_NUM_BANDS)
return false;
n_chans = 0;
for (i = 0; i < req->n_channels; i++) {
if (req->channels[i]->band !=
local->hw_scan_band)
continue;
local->hw_scan_req->req.channels[n_chans] =
req->channels[i];
n_chans++;
bands_used |= BIT(req->channels[i]->band);
}
local->hw_scan_band++;
} while (!n_chans);
}
local->hw_scan_req->req.n_channels = n_chans;
ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
ielen = ieee80211_build_preq_ies(local,
(u8 *)local->hw_scan_req->req.ie,
local->hw_scan_ies_bufsize,
&local->hw_scan_req->ies,
req->ie, req->ie_len,
bands_used, req->rates, &chandef);
local->hw_scan_req->req.ie_len = ielen;
local->hw_scan_req->req.no_cck = req->no_cck;
ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
ether_addr_copy(local->hw_scan_req->req.mac_addr_mask,
req->mac_addr_mask);
return true;
}
static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
{
struct ieee80211_local *local = hw_to_local(hw);
bool hw_scan = local->ops->hw_scan;
bool was_scanning = local->scanning;
struct cfg80211_scan_request *scan_req;
struct ieee80211_sub_if_data *scan_sdata;
lockdep_assert_held(&local->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))
return;
if (hw_scan && !aborted &&
!ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) &&
ieee80211_prep_hw_scan(local)) {
int rc;
rc = drv_hw_scan(local,
rcu_dereference_protected(local->scan_sdata,
lockdep_is_held(&local->mtx)),
local->hw_scan_req);
if (rc == 0)
return;
}
kfree(local->hw_scan_req);
local->hw_scan_req = NULL;
scan_req = rcu_dereference_protected(local->scan_req,
lockdep_is_held(&local->mtx));
if (scan_req != local->int_scan_req)
cfg80211_scan_done(scan_req, aborted);
RCU_INIT_POINTER(local->scan_req, NULL);
scan_sdata = rcu_dereference_protected(local->scan_sdata,
lockdep_is_held(&local->mtx));
RCU_INIT_POINTER(local->scan_sdata, NULL);
local->scanning = 0;
local->scan_chandef.chan = NULL;
/* Set power back to normal operating levels. */
ieee80211_hw_config(local, 0);
if (!hw_scan) {
ieee80211_configure_filter(local);
drv_sw_scan_complete(local, scan_sdata);
ieee80211_offchannel_return(local);
}
ieee80211_recalc_idle(local);
ieee80211_mlme_notify_scan_completed(local);
ieee80211_ibss_notify_scan_completed(local);
ieee80211_mesh_notify_scan_completed(local);
if (was_scanning)
ieee80211_start_next_roc(local);
}
void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
{
struct ieee80211_local *local = hw_to_local(hw);
trace_api_scan_completed(local, aborted);
set_bit(SCAN_COMPLETED, &local->scanning);
if (aborted)
set_bit(SCAN_ABORTED, &local->scanning);
ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
}
EXPORT_SYMBOL(ieee80211_scan_completed);
static int ieee80211_start_sw_scan(struct ieee80211_local *local,
struct ieee80211_sub_if_data *sdata)
{
/* Software scan is not supported in multi-channel cases */
if (local->use_chanctx)
return -EOPNOTSUPP;
/*
* 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, sdata, local->scan_addr);
local->leave_oper_channel_time = jiffies;
local->next_scan_state = SCAN_DECISION;
local->scan_channel_idx = 0;
ieee80211_offchannel_stop_vifs(local);
/* ensure nullfunc is transmitted before leaving operating channel */
ieee80211_flush_queues(local, NULL, false);
ieee80211_configure_filter(local);
/* We need to set power level at maximum rate for scanning. */
ieee80211_hw_config(local, 0);
ieee80211_queue_delayed_work(&local->hw,
&local->scan_work, 0);
return 0;
}
static bool ieee80211_can_scan(struct ieee80211_local *local,
struct ieee80211_sub_if_data *sdata)
{
if (ieee80211_is_radar_required(local))
return false;
if (!list_empty(&local->roc_list))
return false;
if (sdata->vif.type == NL80211_IFTYPE_STATION &&
sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
return false;
return true;
}
void ieee80211_run_deferred_scan(struct ieee80211_local *local)
{
lockdep_assert_held(&local->mtx);
if (!local->scan_req || local->scanning)
return;
if (!ieee80211_can_scan(local,
rcu_dereference_protected(
local->scan_sdata,
lockdep_is_held(&local->mtx))))
return;
ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
round_jiffies_relative(0));
}
static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
unsigned long *next_delay)
{
int i;
struct ieee80211_sub_if_data *sdata;
struct cfg80211_scan_request *scan_req;
enum ieee80211_band band = local->hw.conf.chandef.chan->band;
u32 tx_flags;
scan_req = rcu_dereference_protected(local->scan_req,
lockdep_is_held(&local->mtx));
tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
if (scan_req->no_cck)
tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
sdata = rcu_dereference_protected(local->scan_sdata,
lockdep_is_held(&local->mtx));
for (i = 0; i < scan_req->n_ssids; i++)
ieee80211_send_probe_req(
sdata, local->scan_addr, NULL,
scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
scan_req->ie, scan_req->ie_len,
scan_req->rates[band], false,
tx_flags, local->hw.conf.chandef.chan, true);
/*
* After sending probe requests, wait for probe responses
* on the channel.
*/
*next_delay = IEEE80211_CHANNEL_TIME;
local->next_scan_state = SCAN_DECISION;
}
static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
struct cfg80211_scan_request *req)
{
struct ieee80211_local *local = sdata->local;
int rc;
lockdep_assert_held(&local->mtx);
if (local->scan_req || ieee80211_is_radar_required(local))
return -EBUSY;
if (!ieee80211_can_scan(local, sdata)) {
/* wait for the work to finish/time out */
rcu_assign_pointer(local->scan_req, req);
rcu_assign_pointer(local->scan_sdata, sdata);
return 0;
}
if (local->ops->hw_scan) {
u8 *ies;
local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
int i, n_bands = 0;
u8 bands_counted = 0;
for (i = 0; i < req->n_channels; i++) {
if (bands_counted & BIT(req->channels[i]->band))
continue;
bands_counted |= BIT(req->channels[i]->band);
n_bands++;
}
local->hw_scan_ies_bufsize *= n_bands;
}
local->hw_scan_req = kmalloc(
sizeof(*local->hw_scan_req) +
req->n_channels * sizeof(req->channels[0]) +
local->hw_scan_ies_bufsize, GFP_KERNEL);
if (!local->hw_scan_req)
return -ENOMEM;
local->hw_scan_req->req.ssids = req->ssids;
local->hw_scan_req->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->req.ie = ies;
local->hw_scan_req->req.flags = req->flags;
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.
*/
}
rcu_assign_pointer(local->scan_req, req);
rcu_assign_pointer(local->scan_sdata, sdata);
if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
get_random_mask_addr(local->scan_addr,
req->mac_addr,
req->mac_addr_mask);
else
memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
if (local->ops->hw_scan) {
__set_bit(SCAN_HW_SCANNING, &local->scanning);
} else if ((req->n_channels == 1) &&
(req->channels[0] == local->_oper_chandef.chan)) {
/*
* If we are scanning only on the operating channel
* then we do not need to stop normal activities
*/
unsigned long next_delay;
__set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
ieee80211_recalc_idle(local);
/* Notify driver scan is starting, keep order of operations
* same as normal software scan, in case that matters. */
drv_sw_scan_start(local, sdata, local->scan_addr);
ieee80211_configure_filter(local); /* accept probe-responses */
/* We need to ensure power level is at max for scanning. */
ieee80211_hw_config(local, 0);
if ((req->channels[0]->flags &
IEEE80211_CHAN_NO_IR) ||
!req->n_ssids) {
next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
} else {
ieee80211_scan_state_send_probe(local, &next_delay);
next_delay = IEEE80211_CHANNEL_TIME;
}
/* Now, just wait a bit and we are all done! */
ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
next_delay);
return 0;
} else {
/* Do normal software scan */
__set_bit(SCAN_SW_SCANNING, &local->scanning);
}
ieee80211_recalc_idle(local);
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, sdata);
}
if (rc) {
kfree(local->hw_scan_req);
local->hw_scan_req = NULL;
local->scanning = 0;
ieee80211_recalc_idle(local);
local->scan_req = NULL;
RCU_INIT_POINTER(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_NO_IR)
return IEEE80211_PASSIVE_CHANNEL_TIME;
return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
}
static void ieee80211_scan_state_decision(struct ieee80211_local *local,
unsigned long *next_delay)
{
bool associated = false;
bool tx_empty = true;
bool bad_latency;
struct ieee80211_sub_if_data *sdata;
struct ieee80211_channel *next_chan;
enum mac80211_scan_state next_scan_state;
struct cfg80211_scan_request *scan_req;
/*
* 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 (!qdisc_all_tx_empty(sdata->dev)) {
tx_empty = false;
break;
}
}
}
}
mutex_unlock(&local->iflist_mtx);
scan_req = rcu_dereference_protected(local->scan_req,
lockdep_is_held(&local->mtx));
next_chan = scan_req->channels[local->scan_channel_idx];
/*
* we're currently scanning a different channel, let's
* see if we can scan another channel without interfering
* with the current traffic situation.
*
* Keep good latency, do not stay off-channel more than 125 ms.
*/
bad_latency = time_after(jiffies +
ieee80211_scan_get_channel_time(next_chan),
local->leave_oper_channel_time + HZ / 8);
if (associated && !tx_empty) {
if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
next_scan_state = SCAN_ABORT;
else
next_scan_state = SCAN_SUSPEND;
} else if (associated && bad_latency) {
next_scan_state = SCAN_SUSPEND;
} else {
next_scan_state = SCAN_SET_CHANNEL;
}
local->next_scan_state = next_scan_state;
*next_delay = 0;
}
static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
unsigned long *next_delay)
{
int skip;
struct ieee80211_channel *chan;
enum nl80211_bss_scan_width oper_scan_width;
struct cfg80211_scan_request *scan_req;
scan_req = rcu_dereference_protected(local->scan_req,
lockdep_is_held(&local->mtx));
skip = 0;
chan = scan_req->channels[local->scan_channel_idx];
local->scan_chandef.chan = chan;
local->scan_chandef.center_freq1 = chan->center_freq;
local->scan_chandef.center_freq2 = 0;
switch (scan_req->scan_width) {
case NL80211_BSS_CHAN_WIDTH_5:
local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
break;
case NL80211_BSS_CHAN_WIDTH_10:
local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
break;
case NL80211_BSS_CHAN_WIDTH_20:
/* If scanning on oper channel, use whatever channel-type
* is currently in use.
*/
oper_scan_width = cfg80211_chandef_to_scan_width(
&local->_oper_chandef);
if (chan == local->_oper_chandef.chan &&
oper_scan_width == scan_req->scan_width)
local->scan_chandef = local->_oper_chandef;
else
local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
break;
}
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_NO_IR || !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_suspend(struct ieee80211_local *local,
unsigned long *next_delay)
{
/* switch back to the operating channel */
local->scan_chandef.chan = NULL;
ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
/* disable PS */
ieee80211_offchannel_return(local);
*next_delay = HZ / 5;
/* afterwards, resume scan & go to next channel */
local->next_scan_state = SCAN_RESUME;
}
static void ieee80211_scan_state_resume(struct ieee80211_local *local,
unsigned long *next_delay)
{
ieee80211_offchannel_stop_vifs(local);
if (local->ops->flush) {
ieee80211_flush_queues(local, NULL, false);
*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;
}
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;
struct cfg80211_scan_request *scan_req;
unsigned long next_delay = 0;
bool aborted;
mutex_lock(&local->mtx);
if (!ieee80211_can_run_worker(local)) {
aborted = true;
goto out_complete;
}
sdata = rcu_dereference_protected(local->scan_sdata,
lockdep_is_held(&local->mtx));
scan_req = rcu_dereference_protected(local->scan_req,
lockdep_is_held(&local->mtx));
/* When scanning on-channel, the first-callback means completed. */
if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
goto out_complete;
}
if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
goto out_complete;
}
if (!sdata || !scan_req)
goto out;
if (!local->scanning) {
int rc;
RCU_INIT_POINTER(local->scan_req, NULL);
RCU_INIT_POINTER(local->scan_sdata, NULL);
rc = __ieee80211_start_scan(sdata, scan_req);
if (rc) {
/* need to complete scan in cfg80211 */
rcu_assign_pointer(local->scan_req, scan_req);
aborted = true;
goto out_complete;
} else
goto out;
}
/*
* as long as no delay is required advance immediately
* without scheduling a new work
*/
do {
if (!ieee80211_sdata_running(sdata)) {
aborted = true;
goto out_complete;
}
switch (local->next_scan_state) {
case SCAN_DECISION:
/* if no more bands/channels left, complete scan */
if (local->scan_channel_idx >= scan_req->n_channels) {
aborted = false;
goto out_complete;
}
ieee80211_scan_state_decision(local, &next_delay);
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_SUSPEND:
ieee80211_scan_state_suspend(local, &next_delay);
break;
case SCAN_RESUME:
ieee80211_scan_state_resume(local, &next_delay);
break;
case SCAN_ABORT:
aborted = true;
goto out_complete;
}
} while (next_delay == 0);
ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
goto out;
out_complete:
__ieee80211_scan_completed(&local->hw, aborted);
out:
mutex_unlock(&local->mtx);
}
int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
struct cfg80211_scan_request *req)
{
int res;
mutex_lock(&sdata->local->mtx);
res = __ieee80211_start_scan(sdata, req);
mutex_unlock(&sdata->local->mtx);
return res;
}
int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
const u8 *ssid, u8 ssid_len,
struct ieee80211_channel **channels,
unsigned int n_channels,
enum nl80211_bss_scan_width scan_width)
{
struct ieee80211_local *local = sdata->local;
int ret = -EBUSY, i, n_ch = 0;
enum ieee80211_band band;
mutex_lock(&local->mtx);
/* busy scanning */
if (local->scan_req)
goto unlock;
/* fill internal scan request */
if (!channels) {
int max_n;
for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
if (!local->hw.wiphy->bands[band])
continue;
max_n = local->hw.wiphy->bands[band]->n_channels;
for (i = 0; i < max_n; i++) {
struct ieee80211_channel *tmp_ch =
&local->hw.wiphy->bands[band]->channels[i];
if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
IEEE80211_CHAN_DISABLED))
continue;
local->int_scan_req->channels[n_ch] = tmp_ch;
n_ch++;
}
}
if (WARN_ON_ONCE(n_ch == 0))
goto unlock;
local->int_scan_req->n_channels = n_ch;
} else {
for (i = 0; i < n_channels; i++) {
if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
IEEE80211_CHAN_DISABLED))
continue;
local->int_scan_req->channels[n_ch] = channels[i];
n_ch++;
}
if (WARN_ON_ONCE(n_ch == 0))
goto unlock;
local->int_scan_req->n_channels = n_ch;
}
local->int_scan_req->ssids = &local->scan_ssid;
local->int_scan_req->n_ssids = 1;
local->int_scan_req->scan_width = scan_width;
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->mtx);
return ret;