cfg80211: Add option to specify previous BSSID for Connect command

This extends NL80211_CMD_CONNECT to allow the NL80211_ATTR_PREV_BSSID
attribute to be used similarly to way this was already allowed with
NL80211_CMD_ASSOCIATE. This allows user space to request reassociation
(instead of association) when already connected to an AP. This provides
an option to reassociate within an ESS without having to disconnect and
associate with the AP.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/cfg80211.h

@@ -1925,6 +1925,7 @@ struct cfg80211_bss_selection {
  * @pbss: if set, connect to a PCP instead of AP. Valid for DMG
  *	networks.
  * @bss_select: criteria to be used for BSS selection.
+ * @prev_bssid: previous BSSID, if not %NULL use reassociate frame
  */
 struct cfg80211_connect_params {
 	struct ieee80211_channel *channel;
@@ -1949,6 +1950,7 @@ struct cfg80211_connect_params {
 	struct ieee80211_vht_cap vht_capa_mask;
 	bool pbss;
 	struct cfg80211_bss_selection bss_select;
+	const u8 *prev_bssid;
 };
 
 /**

net/wireless/nl80211.c

@@ -8058,6 +8058,10 @@ static int nl80211_connect(struct sk_buff *skb, struct genl_info *info)
 		connect.mfp = NL80211_MFP_NO;
 	}
 
+	if (info->attrs[NL80211_ATTR_PREV_BSSID])
+		connect.prev_bssid =
+			nla_data(info->attrs[NL80211_ATTR_PREV_BSSID]);
+
 	if (info->attrs[NL80211_ATTR_WIPHY_FREQ]) {
 		connect.channel = nl80211_get_valid_chan(
 			wiphy, info->attrs[NL80211_ATTR_WIPHY_FREQ]);

net/wireless/trace.h

@@ -1259,6 +1259,7 @@ TRACE_EVENT(rdev_connect,
 		__field(bool, privacy)
 		__field(u32, wpa_versions)
 		__field(u32, flags)
+		MAC_ENTRY(prev_bssid)
 	),
 	TP_fast_assign(
 		WIPHY_ASSIGN;
@@ -1270,13 +1271,14 @@ TRACE_EVENT(rdev_connect,
 		__entry->privacy = sme->privacy;
 		__entry->wpa_versions = sme->crypto.wpa_versions;
 		__entry->flags = sme->flags;
+		MAC_ASSIGN(prev_bssid, sme->prev_bssid);
 	),
 	TP_printk(WIPHY_PR_FMT ", " NETDEV_PR_FMT ", bssid: " MAC_PR_FMT
 		  ", ssid: %s, auth type: %d, privacy: %s, wpa versions: %u, "
-		  "flags: %u",
+		  "flags: %u, previous bssid: " MAC_PR_FMT,
 		  WIPHY_PR_ARG, NETDEV_PR_ARG, MAC_PR_ARG(bssid), __entry->ssid,
 		  __entry->auth_type, BOOL_TO_STR(__entry->privacy),
-		  __entry->wpa_versions, __entry->flags)
+		  __entry->wpa_versions, __entry->flags, MAC_PR_ARG(prev_bssid))
 );
 
 TRACE_EVENT(rdev_set_cqm_rssi_config,