batman-adv: add broadcast duplicate check

When multiple backbone gateways relay the same broadcast from the
backbone into the mesh, other nodes in the mesh may receive this
broadcast multiple times. To avoid this, the crc checksums of
received broadcasts are recorded and new broadcast packets with
the same content may be dropped if received by another gateway.

Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/net/batman-adv/main.h b/net/batman-adv/main.h
index 82723b5dce61..d9832acf558d 100644
--- a/net/batman-adv/main.h
+++ b/net/batman-adv/main.h
@@ -83,6 +83,9 @@
 #define BLA_PERIOD_LENGTH       10000   /* 10 seconds */
 #define BLA_BACKBONE_TIMEOUT    (BLA_PERIOD_LENGTH * 3)
 #define BLA_CLAIM_TIMEOUT       (BLA_PERIOD_LENGTH * 10)
+
+#define DUPLIST_SIZE            16
+#define DUPLIST_TIMEOUT         500     /* 500 ms */
 /* don't reset again within 30 seconds */
 #define RESET_PROTECTION_MS 30000
 #define EXPECTED_SEQNO_RANGE    65536