[RFC 3/4] mac80211: Support LIVE_ADDRESS_CHANGE feature

[James Prestwood <prestwoj@gmail.com>]

---
 net/mac80211/iface.c | 51 ++++++++++++++++++++++++++++++++++++++++++--
 net/mac80211/main.c  |  1 +
 2 files changed, 50 insertions(+), 2 deletions(-)

diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 8dc6580e1787..16ef6b83e7ea 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -198,15 +198,57 @@ static int ieee80211_verify_mac(struct ieee80211_sub_if_data *sdata, u8 *addr,
 	return ret;
 }
 
+static int ieee80211_can_live_addr_change(struct ieee80211_sub_if_data *sdata)
+{
+	if (netif_carrier_ok(sdata->dev))
+		return -EBUSY;
+
+	switch (sdata->vif.type) {
+	case NL80211_IFTYPE_AP:
+	case NL80211_IFTYPE_P2P_GO:
+	case NL80211_IFTYPE_AP_VLAN:
+	case NL80211_IFTYPE_WDS:
+	case NL80211_IFTYPE_MESH_POINT:
+	case NL80211_IFTYPE_MONITOR:
+	case NL80211_IFTYPE_OCB:
+		/* No further checking required, when started or UP these
+		 * interface types set carrier
+		 */
+		break;
+	case NL80211_IFTYPE_ADHOC:
+		if (sdata->u.ibss.ssid_len != 0)
+			return -EBUSY;
+		break;
+	case NL80211_IFTYPE_STATION:
+	case NL80211_IFTYPE_P2P_CLIENT:
+		if (!list_empty(&sdata->local->roc_list) ||
+					!sdata->local->scanning)
+			return -EBUSY;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+
 static int ieee80211_change_mac(struct net_device *dev, void *addr)
 {
 	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+	struct ieee80211_local *local = sdata->local;
 	struct sockaddr *sa = addr;
 	bool check_dup = true;
+	bool live = false;
 	int ret;
 
-	if (ieee80211_sdata_running(sdata))
-		return -EBUSY;
+	if (ieee80211_sdata_running(sdata)) {
+		ret = ieee80211_can_live_addr_change(sdata);
+		if (ret)
+			return ret;
+
+		live = true;
+	}
 
 	if (sdata->vif.type == NL80211_IFTYPE_MONITOR &&
 	    !(sdata->u.mntr.flags & MONITOR_FLAG_ACTIVE))
@@ -216,7 +258,11 @@ static int ieee80211_change_mac(struct net_device *dev, void *addr)
 	if (ret)
 		return ret;
 
+	if (live)
+		drv_remove_interface(local, sdata);
 	ret = eth_mac_addr(dev, sa);
+	if (live)
+		drv_add_interface(local, sdata);
 
 	if (ret == 0)
 		memcpy(sdata->vif.addr, sa->sa_data, ETH_ALEN);
@@ -1871,6 +1917,7 @@ int ieee80211_if_add(struct ieee80211_local *local, const char *name,
 			sdata->u.mgd.use_4addr = params->use_4addr;
 
 		ndev->features |= local->hw.netdev_features;
+		ndev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
 
 		netdev_set_default_ethtool_ops(ndev, &ieee80211_ethtool_ops);
 
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 29b9d57df1a3..0aea583e5e69 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -596,6 +596,7 @@ struct ieee80211_hw *ieee80211_alloc_hw_nm(size_t priv_data_len,
 		wiphy_ext_feature_set(wiphy, NL80211_EXT_FEATURE_TXQS);
 
 	wiphy_ext_feature_set(wiphy, NL80211_EXT_FEATURE_RRM);
+	wiphy_ext_feature_set(wiphy, NL80211_EXT_FEATURE_LIVE_ADDRESS_CHANGE);
 
 	wiphy->bss_priv_size = sizeof(struct ieee80211_bss);
 
-- 
2.17.1