[PATCH 1/2 V3] nl80211/cfg80211: Add support for drivers with AP SME that require PMF SA Query assistance

[Chet Lanctot <clanctot@codeaurora.org>]

This adds support for drivers that have AP SME integrated but do
not implement the SA Query procedure that is part of Protected
Management Frames (PMF, 802.11w).

Instead, hostapd can be used to assist drivers that lack SA Query
Procedure handling on their own by allowing them to specify this as
a device capability flag.

Also, a station flag is added to let hostapd indicate to the driver
that the SA Query procedure is complete and the driver can process
association requests from the station normally.

Signed-off-by: Chet Lanctot <clanctot@codeaurora.org>
---
 include/uapi/linux/nl80211.h | 14 +++++++++++---
 net/wireless/nl80211.c       |  7 ++++---
 2 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index eb68735..4c80a10 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -1891,6 +1891,9 @@ enum nl80211_iftype {
  * @NL80211_STA_FLAG_ASSOCIATED: station is associated; used with drivers
  *	that support %NL80211_FEATURE_FULL_AP_CLIENT_STATE to transition a
  *	previously added station into associated state
+ * @NL80211_STA_FLAG_NO_SA_QUERY_REQUIRED: hostapd has completed the MFP
+ *	SA Query procedure with the station and no further SA Query is needed
+ *	when an association request is received from the station
  * @NL80211_STA_FLAG_MAX: highest station flag number currently defined
  * @__NL80211_STA_FLAG_AFTER_LAST: internal use
  */
@@ -1903,6 +1906,7 @@ enum nl80211_sta_flags {
 	NL80211_STA_FLAG_AUTHENTICATED,
 	NL80211_STA_FLAG_TDLS_PEER,
 	NL80211_STA_FLAG_ASSOCIATED,
+	NL80211_STA_FLAG_NO_SA_QUERY_REQUIRED,
 
 	/* keep last */
 	__NL80211_STA_FLAG_AFTER_LAST,
@@ -3648,11 +3652,15 @@ enum nl80211_tdls_operation {
 
 /*
  * enum nl80211_ap_sme_features - device-integrated AP features
- * Reserved for future use, no bits are defined in
- * NL80211_ATTR_DEVICE_AP_SME yet.
+ * @NL80211_ATTR_AP_SME_NO_SA_QUERY: The driver for this device
+ *	implments the AP SME but lacks support for doing the MFP SA
+ *	Query procedure.  This flag is used to express the need for
+ *	a userspace helper (hostapd) to do this procedure and notifiy
+ *	the driver through cfg80211 when it is complete.
+ */
 enum nl80211_ap_sme_features {
+	NL80211_AP_SME_FEATURE_NO_SA_QUERY
 };
- */
 
 /**
  * enum nl80211_feature_flags - device/driver features
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 587ff84..276e4a3 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -3689,7 +3689,7 @@ int cfg80211_check_station_change(struct wiphy *wiphy,
 		return -EINVAL;
 
 	/* When you run into this, adjust the code below for the new flag */
-	BUILD_BUG_ON(NL80211_STA_FLAG_MAX != 7);
+	BUILD_BUG_ON(NL80211_STA_FLAG_MAX != 8);
 
 	switch (statype) {
 	case CFG80211_STA_MESH_PEER_KERNEL:
@@ -3766,7 +3766,8 @@ int cfg80211_check_station_change(struct wiphy *wiphy,
 				  BIT(NL80211_STA_FLAG_ASSOCIATED) |
 				  BIT(NL80211_STA_FLAG_SHORT_PREAMBLE) |
 				  BIT(NL80211_STA_FLAG_WME) |
-				  BIT(NL80211_STA_FLAG_MFP)))
+				  BIT(NL80211_STA_FLAG_MFP) |
+				  BIT(NL80211_STA_FLAG_NO_SA_QUERY_REQUIRED)))
 			return -EINVAL;
 
 		/* but authenticated/associated only if driver handles it */
@@ -4090,7 +4091,7 @@ static int nl80211_new_station(struct sk_buff *skb, struct genl_info *info)
 		return -EINVAL;
 
 	/* When you run into this, adjust the code below for the new flag */
-	BUILD_BUG_ON(NL80211_STA_FLAG_MAX != 7);
+	BUILD_BUG_ON(NL80211_STA_FLAG_MAX != 8);
 
 	switch (dev->ieee80211_ptr->iftype) {
 	case NL80211_IFTYPE_AP:
-- 
1.7.12.rc0.22.gcdd159b