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mac80211: refactor the scan code
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Move the processing of each scan state into its own functions for better
readability. This patch does not introduce functional changes.

Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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Helmut Schaa authored and John W. Linville committed Jul 27, 2009
1 parent 4ef7084 commit 7d3be3c
Showing 1 changed file with 78 additions and 58 deletions.
136 changes: 78 additions & 58 deletions net/mac80211/scan.c
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Original file line number Diff line number Diff line change
Expand Up @@ -474,13 +474,87 @@ static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
return rc;
}

static int ieee80211_scan_state_set_channel(struct ieee80211_local *local,
unsigned long *next_delay)
{
int skip;
struct ieee80211_channel *chan;
struct ieee80211_sub_if_data *sdata = local->scan_sdata;

/* if no more bands/channels left, complete scan */
if (local->scan_channel_idx >= local->scan_req->n_channels) {
ieee80211_scan_completed(&local->hw, false);
return 1;
}
skip = 0;
chan = local->scan_req->channels[local->scan_channel_idx];

if (chan->flags & IEEE80211_CHAN_DISABLED ||
(sdata->vif.type == NL80211_IFTYPE_ADHOC &&
chan->flags & IEEE80211_CHAN_NO_IBSS))
skip = 1;

if (!skip) {
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)
return 0;

/*
* 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;
return 0;
}

*next_delay = IEEE80211_PROBE_DELAY;
local->scan_state = SCAN_SEND_PROBE;

return 0;
}

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->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 = local->scan_sdata;
struct ieee80211_channel *chan;
int skip, i;
unsigned long next_delay = 0;

mutex_lock(&local->scan_mtx);
Expand Down Expand Up @@ -515,65 +589,11 @@ void ieee80211_scan_work(struct work_struct *work)

switch (local->scan_state) {
case SCAN_SET_CHANNEL:
/* if no more bands/channels left, complete scan */
if (local->scan_channel_idx >= local->scan_req->n_channels) {
ieee80211_scan_completed(&local->hw, false);
if (ieee80211_scan_state_set_channel(local, &next_delay))
return;
}
skip = 0;
chan = local->scan_req->channels[local->scan_channel_idx];

if (chan->flags & IEEE80211_CHAN_DISABLED ||
(sdata->vif.type == NL80211_IFTYPE_ADHOC &&
chan->flags & IEEE80211_CHAN_NO_IBSS))
skip = 1;

if (!skip) {
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)
break;

/*
* 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;
break;
}

next_delay = IEEE80211_PROBE_DELAY;
local->scan_state = SCAN_SEND_PROBE;
break;
case SCAN_SEND_PROBE:
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->scan_state = SCAN_SET_CHANNEL;
ieee80211_scan_state_send_probe(local, &next_delay);
break;
}

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