+++ /dev/null
-From 42f417212a8d02cacbd4ee288e9aa542d9283ff8 Mon Sep 17 00:00:00 2001
-From: Jouni Malinen <jouni@codeaurora.org>
-Date: Wed, 5 Sep 2018 18:52:22 +0300
-Subject: cfg80211: Address some corner cases in scan result channel updating
-
-[ Upstream commit 119f94a6fefcc76d47075b83d2b73d04c895df78 ]
-
-cfg80211_get_bss_channel() is used to update the RX channel based on the
-available frame payload information (channel number from DSSS Parameter
-Set element or HT Operation element). This is needed on 2.4 GHz channels
-where frames may be received on neighboring channels due to overlapping
-frequency range.
-
-This might of some use on the 5 GHz band in some corner cases, but
-things are more complex there since there is no n:1 or 1:n mapping
-between channel numbers and frequencies due to multiple different
-starting frequencies in different operating classes. This could result
-in ieee80211_channel_to_frequency() returning incorrect frequency and
-ieee80211_get_channel() returning incorrect channel information (or
-indication of no match). In the previous implementation, this could
-result in some scan results being dropped completely, e.g., for the 4.9
-GHz channels. That prevented connection to such BSSs.
-
-Fix this by using the driver-provided channel pointer if
-ieee80211_get_channel() does not find matching channel data for the
-channel number in the frame payload and if the scan is done with 5 MHz
-or 10 MHz channel bandwidth. While doing this, also add comments
-describing what the function is trying to achieve to make it easier to
-understand what happens here and why.
-
-Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
-Signed-off-by: Johannes Berg <johannes.berg@intel.com>
-Signed-off-by: Sasha Levin <sashal@kernel.org>
----
- net/wireless/scan.c | 58 ++++++++++++++++++++++++++++++++++++++-------
- 1 file changed, 49 insertions(+), 9 deletions(-)
-
-diff --git a/net/wireless/scan.c b/net/wireless/scan.c
-index 8dde12a11725..00219f386283 100644
---- a/net/wireless/scan.c
-+++ b/net/wireless/scan.c
-@@ -974,13 +974,23 @@ cfg80211_bss_update(struct cfg80211_registered_device *rdev,
- return NULL;
- }
-
-+/*
-+ * Update RX channel information based on the available frame payload
-+ * information. This is mainly for the 2.4 GHz band where frames can be received
-+ * from neighboring channels and the Beacon frames use the DSSS Parameter Set
-+ * element to indicate the current (transmitting) channel, but this might also
-+ * be needed on other bands if RX frequency does not match with the actual
-+ * operating channel of a BSS.
-+ */
- static struct ieee80211_channel *
- cfg80211_get_bss_channel(struct wiphy *wiphy, const u8 *ie, size_t ielen,
-- struct ieee80211_channel *channel)
-+ struct ieee80211_channel *channel,
-+ enum nl80211_bss_scan_width scan_width)
- {
- const u8 *tmp;
- u32 freq;
- int channel_number = -1;
-+ struct ieee80211_channel *alt_channel;
-
- tmp = cfg80211_find_ie(WLAN_EID_DS_PARAMS, ie, ielen);
- if (tmp && tmp[1] == 1) {
-@@ -994,16 +1004,45 @@ cfg80211_get_bss_channel(struct wiphy *wiphy, const u8 *ie, size_t ielen,
- }
- }
-
-- if (channel_number < 0)
-+ if (channel_number < 0) {
-+ /* No channel information in frame payload */
- return channel;
-+ }
-
- freq = ieee80211_channel_to_frequency(channel_number, channel->band);
-- channel = ieee80211_get_channel(wiphy, freq);
-- if (!channel)
-- return NULL;
-- if (channel->flags & IEEE80211_CHAN_DISABLED)
-+ alt_channel = ieee80211_get_channel(wiphy, freq);
-+ if (!alt_channel) {
-+ if (channel->band == NL80211_BAND_2GHZ) {
-+ /*
-+ * Better not allow unexpected channels when that could
-+ * be going beyond the 1-11 range (e.g., discovering
-+ * BSS on channel 12 when radio is configured for
-+ * channel 11.
-+ */
-+ return NULL;
-+ }
-+
-+ /* No match for the payload channel number - ignore it */
-+ return channel;
-+ }
-+
-+ if (scan_width == NL80211_BSS_CHAN_WIDTH_10 ||
-+ scan_width == NL80211_BSS_CHAN_WIDTH_5) {
-+ /*
-+ * Ignore channel number in 5 and 10 MHz channels where there
-+ * may not be an n:1 or 1:n mapping between frequencies and
-+ * channel numbers.
-+ */
-+ return channel;
-+ }
-+
-+ /*
-+ * Use the channel determined through the payload channel number
-+ * instead of the RX channel reported by the driver.
-+ */
-+ if (alt_channel->flags & IEEE80211_CHAN_DISABLED)
- return NULL;
-- return channel;
-+ return alt_channel;
- }
-
- /* Returned bss is reference counted and must be cleaned up appropriately. */
-@@ -1028,7 +1067,8 @@ cfg80211_inform_bss_data(struct wiphy *wiphy,
- (data->signal < 0 || data->signal > 100)))
- return NULL;
-
-- channel = cfg80211_get_bss_channel(wiphy, ie, ielen, data->chan);
-+ channel = cfg80211_get_bss_channel(wiphy, ie, ielen, data->chan,
-+ data->scan_width);
- if (!channel)
- return NULL;
-
-@@ -1126,7 +1166,7 @@ cfg80211_inform_bss_frame_data(struct wiphy *wiphy,
- return NULL;
-
- channel = cfg80211_get_bss_channel(wiphy, mgmt->u.beacon.variable,
-- ielen, data->chan);
-+ ielen, data->chan, data->scan_width);
- if (!channel)
- return NULL;
-
---
-2.17.1
-
projects / thirdparty / kernel / stable-queue.git / commitdiff
