mac80211: support max channel switch time element

2018 REVmd of the spec introduces the max channel switch time
element which is optionally included in beacons/probes when there
is a channel switch / extended channel switch element.
The value represents the maximum delay between the time the AP
transmitted the last beacon in current channel and the expected
time of the first beacon in the new channel, in TU.

Parse the value and pass it to the driver.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

6 files changed, 18 insertions, 0 deletions

diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h
index 6cbaed4d7a6b..d9650ae2b4f7 100644
--- a/include/linux/ieee80211.h
+++ b/include/linux/ieee80211.h
@@ -2475,6 +2475,7 @@ enum ieee80211_eid_ext {
 	WLAN_EID_EXT_HE_OPERATION = 36,
 	WLAN_EID_EXT_UORA = 37,
 	WLAN_EID_EXT_HE_MU_EDCA = 38,
+	WLAN_EID_EXT_MAX_CHANNEL_SWITCH_TIME = 52,
 	WLAN_EID_EXT_MULTIPLE_BSSID_CONFIGURATION = 55,
 };
 
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 97aed7b1ba5d..3fb38d2bdb4f 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -1519,6 +1519,9 @@ struct ieee80211_conf {
  *	scheduled channel switch, as indicated by the AP.
  * @chandef: the new channel to switch to
  * @count: the number of TBTT's until the channel switch event
+ * @delay: maximum delay between the time the AP transmitted the last beacon in
+  *	current channel and the expected time of the first beacon in the new
+  *	channel, expressed in TU.
  */
 struct ieee80211_channel_switch {
 	u64 timestamp;
@@ -1526,6 +1529,7 @@ struct ieee80211_channel_switch {
 	bool block_tx;
 	struct cfg80211_chan_def chandef;
 	u8 count;
+	u32 delay;
 };
 
 /**
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index afce50da6fd6..e170f986d226 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1453,6 +1453,7 @@ struct ieee80211_csa_ie {
 	u8 ttl;
 	u16 pre_value;
 	u16 reason_code;
+	u32 max_switch_time;
 };
 
 /* Parsed Information Elements */
@@ -1493,6 +1494,7 @@ struct ieee802_11_elems {
 	const struct ieee80211_channel_sw_ie *ch_switch_ie;
 	const struct ieee80211_ext_chansw_ie *ext_chansw_ie;
 	const struct ieee80211_wide_bw_chansw_ie *wide_bw_chansw_ie;
+	const u8 *max_channel_switch_time;
 	const u8 *country_elem;
 	const u8 *pwr_constr_elem;
 	const u8 *cisco_dtpc_elem;
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index df5d4b90616d..1b4938d100d5 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -1352,6 +1352,7 @@ ieee80211_sta_process_chanswitch(struct ieee80211_sub_if_data *sdata,
 	ch_switch.block_tx = csa_ie.mode;
 	ch_switch.chandef = csa_ie.chandef;
 	ch_switch.count = csa_ie.count;
+	ch_switch.delay = csa_ie.max_switch_time;
 
 	if (drv_pre_channel_switch(sdata, &ch_switch)) {
 		sdata_info(sdata,
diff --git a/net/mac80211/spectmgmt.c b/net/mac80211/spectmgmt.c
index 4e4902bdbef8..3c644f14dd59 100644
--- a/net/mac80211/spectmgmt.c
+++ b/net/mac80211/spectmgmt.c
@@ -177,6 +177,12 @@ int ieee80211_parse_ch_switch_ie(struct ieee80211_sub_if_data *sdata,
 		csa_ie->chandef = new_vht_chandef;
 	}
 
+	if (elems->max_channel_switch_time)
+		csa_ie->max_switch_time =
+			(elems->max_channel_switch_time[0] << 0) |
+			(elems->max_channel_switch_time[1] <<  8) |
+			(elems->max_channel_switch_time[2] << 16);
+
 	return 0;
 }
 
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 8349c91250ef..3f5a704d1ab0 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -1275,6 +1275,10 @@ _ieee802_11_parse_elems_crc(const u8 *start, size_t len, bool action,
 			} else if (pos[0] == WLAN_EID_EXT_UORA && elen >= 1) {
 				elems->uora_element = (void *)&pos[1];
 			} else if (pos[0] ==
+				   WLAN_EID_EXT_MAX_CHANNEL_SWITCH_TIME &&
+				   elen == 4) {
+				elems->max_channel_switch_time = pos + 1;
+			} else if (pos[0] ==
 				   WLAN_EID_EXT_MULTIPLE_BSSID_CONFIGURATION &&
 				   elen == 3) {
 				elems->mbssid_config_ie = (void *)&pos[1];