[PATCHv2,1/3] mac80211: IBSS fix scan request

Commit Message

[e-mail] March 9, 2015, 6:58 a.m. UTC

In case of wide bandwidth scan all channels we have
in chandef. For example in case of 80MHz bandwidth
we have four possible control channels.

Signed-off-by: Janusz Dziedzic <[e-mail]>
---
 net/mac80211/ibss.c        | 81 ++++++++++++++++++++++++++++++++++++++++++++--
 net/mac80211/ieee80211_i.h |  3 +-
 net/mac80211/scan.c        | 25 ++++++++------
 3 files changed, 97 insertions(+), 12 deletions(-)

Comments

Johannes Berg March 17, 2015, 10:05 a.m. UTC | #1

On Mon, 2015-03-09 at 07:58 +0100, Janusz Dziedzic wrote:
> In case of wide bandwidth scan all channels we have
> in chandef. For example in case of 80MHz bandwidth
> we have four possible control channels.

I think you misunderstood - this doesn't really say *why* either.

It should probably say something like

If channels wider than 20 MHz are used by IBSS, scan all channels in the
chandef to be able to find neighboring IBSS networks that use the same
overall channel but a different control channel.

no?

johannes

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Patch

diff --git a/net/mac80211/ibss.c b/net/mac80211/ibss.c
index ee93d7d..650e69c 100644
--- a/net/mac80211/ibss.c
+++ b/net/mac80211/ibss.c
@@ -1258,7 +1258,7 @@  static void ieee80211_sta_merge_ibss(struct ieee80211_sub_if_data *sdata)
 
 	scan_width = cfg80211_chandef_to_scan_width(&ifibss->chandef);
 	ieee80211_request_ibss_scan(sdata, ifibss->ssid, ifibss->ssid_len,
-				    NULL, scan_width);
+				    NULL, 0, scan_width);
 }
 
 static void ieee80211_sta_create_ibss(struct ieee80211_sub_if_data *sdata)
@@ -1297,6 +1297,76 @@  static void ieee80211_sta_create_ibss(struct ieee80211_sub_if_data *sdata)
 				  capability, 0, true);
 }
 
+static unsigned ibss_setup_channels(struct wiphy *wiphy,
+				    struct ieee80211_channel **channels,
+				    unsigned int channels_max,
+				    u32 center_freq, u32 width)
+{
+	struct ieee80211_channel *chan = NULL;
+	unsigned int n_chan = 0;
+	u32 start_freq, end_freq, freq;
+
+	if (width <= 20) {
+		start_freq = center_freq;
+		end_freq = center_freq;
+	} else {
+		start_freq = center_freq - width/2 + 10;
+		end_freq = center_freq + width/2 - 10;
+	}
+
+	for (freq = start_freq; freq <= end_freq; freq += 20) {
+		chan = ieee80211_get_channel(wiphy, freq);
+		if (!chan)
+			continue;
+		if (n_chan >= channels_max)
+			return n_chan;
+
+		channels[n_chan] = chan;
+		n_chan++;
+	}
+
+	return n_chan;
+}
+
+static unsigned int
+ieee80211_ibss_setup_scan_channels(struct wiphy *wiphy,
+				   const struct cfg80211_chan_def *chandef,
+				   struct ieee80211_channel **channels,
+				   unsigned int channels_max)
+{
+	unsigned int n_chan = 0;
+	u32 width, cf1, cf2 = 0;
+
+	switch (chandef->width) {
+	case NL80211_CHAN_WIDTH_40:
+		width = 40;
+		break;
+	case NL80211_CHAN_WIDTH_80P80:
+		cf2 = chandef->center_freq2;
+		/* fall through */
+	case NL80211_CHAN_WIDTH_80:
+		width = 80;
+		break;
+	case NL80211_CHAN_WIDTH_160:
+		width = 160;
+		break;
+	default:
+		width = 20;
+		break;
+	}
+
+	cf1 = chandef->center_freq1;
+
+	n_chan = ibss_setup_channels(wiphy, channels, channels_max, cf1, width);
+
+	if (cf2)
+		n_chan += ibss_setup_channels(wiphy, &channels[n_chan],
+					      channels_max - n_chan, cf2,
+					      width);
+
+	return n_chan;
+}
+
 /*
  * This function is called with state == IEEE80211_IBSS_MLME_SEARCH
  */
@@ -1362,11 +1432,18 @@  static void ieee80211_sta_find_ibss(struct ieee80211_sub_if_data *sdata)
 	/* Selected IBSS not found in current scan results - try to scan */
 	if (time_after(jiffies, ifibss->last_scan_completed +
 					IEEE80211_SCAN_INTERVAL)) {
+		struct ieee80211_channel *channels[8];
+		unsigned int num;
+
 		sdata_info(sdata, "Trigger new scan to find an IBSS to join\n");
 
+		num = ieee80211_ibss_setup_scan_channels(local->hw.wiphy,
+							 &ifibss->chandef,
+							 channels,
+							 ARRAY_SIZE(channels));
 		scan_width = cfg80211_chandef_to_scan_width(&ifibss->chandef);
 		ieee80211_request_ibss_scan(sdata, ifibss->ssid,
-					    ifibss->ssid_len, chan,
+					    ifibss->ssid_len, channels, num,
 					    scan_width);
 	} else {
 		int interval = IEEE80211_SCAN_INTERVAL;
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 486a790..856f88d 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1542,7 +1542,8 @@  int ieee80211_mesh_finish_csa(struct ieee80211_sub_if_data *sdata);
 void ieee80211_scan_work(struct work_struct *work);
 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
 				const u8 *ssid, u8 ssid_len,
-				struct ieee80211_channel *chan,
+				struct ieee80211_channel **channels,
+				unsigned int n_channels,
 				enum nl80211_bss_scan_width scan_width);
 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 			   struct cfg80211_scan_request *req);
diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index 05f0d71..7bb6a93 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -928,11 +928,12 @@  int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 
 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
 				const u8 *ssid, u8 ssid_len,
-				struct ieee80211_channel *chan,
+				struct ieee80211_channel **channels,
+				unsigned int n_channels,
 				enum nl80211_bss_scan_width scan_width)
 {
 	struct ieee80211_local *local = sdata->local;
-	int ret = -EBUSY;
+	int ret = -EBUSY, i, n_ch = 0;
 	enum ieee80211_band band;
 
 	mutex_lock(&local->mtx);
@@ -942,9 +943,8 @@  int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
 		goto unlock;
 
 	/* fill internal scan request */
-	if (!chan) {
-		int i, max_n;
-		int n_ch = 0;
+	if (!channels) {
+		int max_n;
 
 		for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 			if (!local->hw.wiphy->bands[band])
@@ -969,12 +969,19 @@  int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
 
 		local->int_scan_req->n_channels = n_ch;
 	} else {
-		if (WARN_ON_ONCE(chan->flags & (IEEE80211_CHAN_NO_IR |
-						IEEE80211_CHAN_DISABLED)))
+		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->channels[0] = chan;
-		local->int_scan_req->n_channels = 1;
+		local->int_scan_req->n_channels = n_ch;
 	}
 
 	local->int_scan_req->ssids = &local->scan_ssid;