From: Sven Eckelmann <sven@narfation.org>
Date: Fri, 9 Jun 2017 17:06:51 +0200
Subject: batman-adv: Accept only filled wifi station info

The wifi driver can decide to not provide parts of the station info. For
example, the expected throughput of the station can be omitted when the
used rate control doesn't provide this kind of information.

The B.A.T.M.A.N. V implementation must therefore check the filled bitfield
before it tries to access the expected_throughput of the returned
station_info.

Reported-by: Alvaro Antelo <alvaro.antelo@gmail.com>
Fixes: 5c3245172c01 ("batman-adv: ELP - compute the metric based on the estimated throughput")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Reviewed-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

Origin: upstream, https://git.open-mesh.org/batman-adv.git/commit/1e26904b364ceffe9ca7d6da7412e70fb2a04178

diff --git a/compat-include/linux/nl80211.h b/compat-include/linux/nl80211.h
new file mode 100644
index 0000000000000000000000000000000000000000..e6654df8cd67caa52a16a1f709141d7415b9f523
--- /dev/null
+++ b/compat-include/linux/nl80211.h
@@ -0,0 +1,14 @@
+#ifndef _NET_BATMAN_ADV_COMPAT_LINUX_NL80211_H_
+#define _NET_BATMAN_ADV_COMPAT_LINUX_NL80211_H_
+
+#include <linux/version.h>
+#include_next <linux/nl80211.h>
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 16, 0)
+
+/* Linux 3.15 misses the uapi include.... */
+#include <uapi/linux/nl80211.h>
+
+#endif /* < KERNEL_VERSION(3, 16, 0) */
+
+#endif	/* _NET_BATMAN_ADV_COMPAT_LINUX_NL80211_H_ */
diff --git a/compat-include/uapi/linux/nl80211.h b/compat-include/uapi/linux/nl80211.h
new file mode 100644
index 0000000000000000000000000000000000000000..06f5625af21360be5718a1a6f7e8949f6739c927
--- /dev/null
+++ b/compat-include/uapi/linux/nl80211.h
@@ -0,0 +1,16 @@
+#ifndef _NET_BATMAN_ADV_COMPAT_UAPI_LINUX_NL80211_H_
+#define _NET_BATMAN_ADV_COMPAT_UAPI_LINUX_NL80211_H_
+
+#include <linux/version.h>
+#include_next <uapi/linux/nl80211.h>
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 0, 0)
+
+/* for batadv_v_elp_get_throughput which would have used
+ * STATION_INFO_EXPECTED_THROUGHPUT in Linux 4.0.0
+ */
+#define NL80211_STA_INFO_EXPECTED_THROUGHPUT    28
+
+#endif /* < KERNEL_VERSION(4, 0, 0) */
+
+#endif	/* _NET_BATMAN_ADV_COMPAT_UAPI_LINUX_NL80211_H_ */
diff --git a/net/batman-adv/bat_v_elp.c b/net/batman-adv/bat_v_elp.c
index 7c54a9291c9eaed75dfdfdfbd200f84c51576cb3..06b2924f4cb7dde54bab97ad2d28aecd9b1a4ceb 100644
--- a/net/batman-adv/bat_v_elp.c
+++ b/net/batman-adv/bat_v_elp.c
@@ -19,6 +19,7 @@
 #include "main.h"
 
 #include <linux/atomic.h>
+#include <linux/bitops.h>
 #include <linux/byteorder/generic.h>
 #include <linux/errno.h>
 #include <linux/etherdevice.h>
@@ -29,6 +30,7 @@
 #include <linux/kernel.h>
 #include <linux/kref.h>
 #include <linux/netdevice.h>
+#include <linux/nl80211.h>
 #include <linux/random.h>
 #include <linux/rculist.h>
 #include <linux/rcupdate.h>
@@ -111,6 +113,8 @@ static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh)
 		}
 		if (ret)
 			goto default_throughput;
+		if (!(sinfo.filled & BIT(NL80211_STA_INFO_EXPECTED_THROUGHPUT)))
+			goto default_throughput;
 
 		return sinfo.expected_throughput / 100;
 	}