Commit 23721387 authored by Simon Wunderlich's avatar Simon Wunderlich Committed by Antonio Quartulli
Browse files

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: default avatarSimon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: default avatarAntonio Quartulli <ordex@autistici.org>
parent a7f6ee94

Documentation/networking/batman-adv.txt

+8 −6
Original line number Diff line number Diff line
@@ -68,9 +68,10 @@ 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

# 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 @@ abled during run time. Following log_levels are defined: 
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.

net/batman-adv/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -4,7 +4,7 @@ 


config BATMAN_ADV

	tristate "B.A.T.M.A.N. Advanced Meshing Protocol"

	depends on NET

	depends on NET && INET

	select CRC16

        default n

	help

net/batman-adv/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ batman-adv-y += bat_debugfs.o 
batman-adv-y += bat_iv_ogm.o

batman-adv-y += bat_sysfs.o

batman-adv-y += bitarray.o

batman-adv-y += bridge_loop_avoidance.o

batman-adv-y += gateway_client.o

batman-adv-y += gateway_common.o

batman-adv-y += hard-interface.o

net/batman-adv/bat_sysfs.c

+1 −1
Original line number Diff line number Diff line
@@ -398,7 +398,7 @@ BAT_ATTR_UINT(gw_sel_class, S_IRUGO | S_IWUSR, 1, TQ_MAX_VALUE, 
static BAT_ATTR(gw_bandwidth, S_IRUGO | S_IWUSR, show_gw_bwidth,

		store_gw_bwidth);

#ifdef CONFIG_BATMAN_ADV_DEBUG

BAT_ATTR_UINT(log_level, S_IRUGO | S_IWUSR, 0, 7, NULL);

BAT_ATTR_UINT(log_level, S_IRUGO | S_IWUSR, 0, 15, NULL);

#endif



static struct bat_attribute *mesh_attrs[] = {

net/batman-adv/bridge_loop_avoidance.c

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+1296 −0

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