batman-adv: add basic bridge loop avoidance code
This second version of the bridge loop avoidance for batman-adv
avoids loops between the mesh and a backbone (usually a LAN).
By connecting multiple batman-adv mesh nodes to the same ethernet
segment a loop can be created when the soft-interface is bridged
into that ethernet segment. A simple visualization of the loop
involving the most common case - a LAN as ethernet segment:
node1 <-- LAN --> node2
| |
wifi <-- mesh --> wifi
Packets from the LAN (e.g. ARP broadcasts) will circle forever from
node1 or node2 over the mesh back into the LAN.
With this patch, batman recognizes backbone gateways, nodes which are
part of the mesh and backbone/LAN at the same time. Each backbone
gateway "claims" clients from within the mesh to handle them
exclusively. By restricting that only responsible backbone gateways
may handle their claimed clients traffic, loops are effectively
avoided.
Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
diff --git a/Documentation/networking/batman-adv.txt b/Documentation/networking/batman-adv.txt
index 221ad0c..9523e9e 100644
--- a/Documentation/networking/batman-adv.txt
+++ b/Documentation/networking/batman-adv.txt
@@ -67,10 +67,11 @@
All mesh wide settings can be found in batman's own interface
folder:
-# ls /sys/class/net/bat0/mesh/
-# aggregated_ogms fragmentation gw_sel_class vis_mode
-# ap_isolation gw_bandwidth hop_penalty
-# bonding gw_mode orig_interval
+# ls /sys/class/net/bat0/mesh/
+# aggregated_ogms fragmentation hop_penalty
+# ap_isolation gw_bandwidth log_level
+# bonding gw_mode orig_interval
+# bridge_loop_avoidance gw_sel_class vis_mode
There is a special folder for debugging information:
@@ -202,12 +203,13 @@
1 - Enable messages related to routing / flooding / broadcasting
2 - Enable messages related to route added / changed / deleted
4 - Enable messages related to translation table operations
-7 - Enable all messages
+8 - Enable messages related to bridge loop avoidance
+15 - enable all messages
The debug output can be changed at runtime using the file
/sys/class/net/bat0/mesh/log_level. e.g.
-# echo 2 > /sys/class/net/bat0/mesh/log_level
+# echo 6 > /sys/class/net/bat0/mesh/log_level
will enable debug messages for when routes change.