batman-adv: check incoming packet type for bla

If the gateway functionality is used, some broadcast packets (DHCP
requests) may be transmitted as unicast packets. As the bridge loop
avoidance code now only considers the payload Ethernet destination,
it may drop the DHCP request for clients which are claimed by other
backbone gateways, because it falsely infers from the broadcast address
that the right backbone gateway should havehandled the broadcast.

Fix this by checking and delegating the batman-adv packet type used
for transmission.

Reported-by: Guido Iribarren <guidoiribarren@buenosaireslibre.org>
Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>

1 files changed, 3 insertions, 2 deletions

diff --git a/net/batman-adv/bridge_loop_avoidance.h b/net/batman-adv/bridge_loop_avoidance.h
index e39f93acc28..dc5227b398d 100644
--- a/net/batman-adv/bridge_loop_avoidance.h
+++ b/net/batman-adv/bridge_loop_avoidance.h
@@ -23,7 +23,8 @@
 #define _NET_BATMAN_ADV_BLA_H_
 
 #ifdef CONFIG_BATMAN_ADV_BLA
-int bla_rx(struct bat_priv *bat_priv, struct sk_buff *skb, short vid);
+int bla_rx(struct bat_priv *bat_priv, struct sk_buff *skb, short vid,
+           bool is_bcast);
 int bla_tx(struct bat_priv *bat_priv, struct sk_buff *skb, short vid);
 int bla_is_backbone_gw(struct sk_buff *skb,
                        struct orig_node *orig_node, int hdr_size);
@@ -41,7 +42,7 @@ void bla_free(struct bat_priv *bat_priv);
 #else /* ifdef CONFIG_BATMAN_ADV_BLA */
 
 static inline int bla_rx(struct bat_priv *bat_priv, struct sk_buff *skb,
-                         short vid)
+                         short vid, bool is_bcast)
 {
         return 0;
 }