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From:   James Prestwood <prestwoj@gmail.com>
To:     linux-wireless@vger.kernel.org
Cc:     James Prestwood <prestwoj@gmail.com>
Subject: [RFC 1/4] nl80211: Add LIVE_ADDR_CHANGE feature
Date:   Wed,  4 Sep 2019 12:11:52 -0700
Message-Id: <20190904191155.28056-2-prestwoj@gmail.com>
In-Reply-To: <20190904191155.28056-1-prestwoj@gmail.com>
References: <20190904191155.28056-1-prestwoj@gmail.com>
Sender: linux-wireless-owner@vger.kernel.org
Precedence: bulk

Add a new feature bit signifying that the wireless hardware supports
changing the mac address while the underlying net_device is UP.  Note
that this is slightly different from IFF_LIVE_ADDR_CHANGE as additional
restrictions might be imposed by the hardware.  Typical restrictions
are:
	- No connection is active on this interface, e.g. carrier is off
	- No scan is in progress
	- No offchannel operation is in progress
---
 include/uapi/linux/nl80211.h | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index bf7c4222f512..0ceb945a08fb 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -5481,6 +5481,14 @@ enum nl80211_feature_flags {
  * @NL80211_EXT_FEATURE_SAE_OFFLOAD: Device wants to do SAE authentication in
  *	station mode (SAE password is passed as part of the connect command).
  *
+ * @NL80211_EXT_FEATURE_LIVE_ADDR_CHANGE: Device can perform a MAC address
+ *	change without having to bring the underlying network device down
+ *	first.  For example, in station mode this can be used to vary the
+ *	origin MAC address prior to a connection to a new AP for privacy
+ *	or other reasons.  Note that certain driver specific restrictions
+ *	might apply, e.g. no scans in progress, no offchannel operations
+ *	in progress, and no active connections.
+ *
  * @NUM_NL80211_EXT_FEATURES: number of extended features.
  * @MAX_NL80211_EXT_FEATURES: highest extended feature index.
  */
@@ -5526,6 +5534,7 @@ enum nl80211_ext_feature_index {
 	NL80211_EXT_FEATURE_EXT_KEY_ID,
 	NL80211_EXT_FEATURE_STA_TX_PWR,
 	NL80211_EXT_FEATURE_SAE_OFFLOAD,
+	NL80211_EXT_FEATURE_LIVE_ADDRESS_CHANGE,
 
 	/* add new features before the definition below */
 	NUM_NL80211_EXT_FEATURES,
-- 
2.17.1