hostapd: fix race condition in mesh new peer handling

Avoid trying to add the same station to the driver multiple times

Signed-off-by: Felix Fietkau <nbd@nbd.name>

package/network/services/hostapd/patches/051-wpa_supplicant-fix-race-condition-in-mesh-mpm-new-pe.patch

@@ -0,0 +1,34 @@
+From: Felix Fietkau <nbd@nbd.name>
+Date: Tue, 12 Feb 2019 14:22:43 +0100
+Subject: [PATCH] wpa_supplicant: fix race condition in mesh mpm new peer
+ handling
+
+When wpa_supplicant receives another new peer event before the first one
+has been processed, it tries to add a station to the driver a second time
+(which fails) and then tears down the station entry until another event
+comes in.
+Fix this by only adding a station to the driver if it didn't exist already.
+
+Signed-off-by: Felix Fietkau <nbd@nbd.name>
+---
+
+--- a/wpa_supplicant/mesh_mpm.c
++++ b/wpa_supplicant/mesh_mpm.c
+@@ -663,11 +663,12 @@ static struct sta_info * mesh_mpm_add_pe
+ 	}
+ 
+ 	sta = ap_get_sta(data, addr);
+-	if (!sta) {
+-		sta = ap_sta_add(data, addr);
+-		if (!sta)
+-			return NULL;
+-	}
++	if (sta)
++		return sta;
++
++	sta = ap_sta_add(data, addr);
++	if (!sta)
++		return NULL;
+ 
+ 	/* Set WMM by default since Mesh STAs are QoS STAs */
+ 	sta->flags |= WLAN_STA_WMM;