batman-adv: Fix broadcast packet CRC calculation
So far the crc16 checksum for a batman-adv broadcast data packet, received
on a batman-adv hard interface, was calculated over zero bytes of its
content leading to many incoming broadcast data packets wrongly being
dropped (60-80% packet loss).
This patch fixes this issue by calculating the crc16 over the actual,
complete broadcast payload.
The issue is a regression introduced by
("batman-adv: add broadcast duplicate check").
Signed-off-by: Linus Lüssing <linus.luessing@web.de>
Acked-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
diff --git a/net/batman-adv/bridge_loop_avoidance.c b/net/batman-adv/bridge_loop_avoidance.c
index 0a9084a..eebab20 100644
--- a/net/batman-adv/bridge_loop_avoidance.c
+++ b/net/batman-adv/bridge_loop_avoidance.c
@@ -1210,8 +1210,8 @@
/**
* batadv_bla_check_bcast_duplist
* @bat_priv: the bat priv with all the soft interface information
- * @bcast_packet: originator mac address
- * @hdr_size: maximum length of the frame
+ * @bcast_packet: encapsulated broadcast frame plus batman header
+ * @bcast_packet_len: length of encapsulated broadcast frame plus batman header
*
* check if it is on our broadcast list. Another gateway might
* have sent the same packet because it is connected to the same backbone,
@@ -1224,14 +1224,14 @@
*/
int batadv_bla_check_bcast_duplist(struct batadv_priv *bat_priv,
struct batadv_bcast_packet *bcast_packet,
- int hdr_size)
+ int bcast_packet_len)
{
int i, length, curr;
uint8_t *content;
uint16_t crc;
struct batadv_bcast_duplist_entry *entry;
- length = hdr_size - sizeof(*bcast_packet);
+ length = bcast_packet_len - sizeof(*bcast_packet);
content = (uint8_t *)bcast_packet;
content += sizeof(*bcast_packet);
diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c
index 939fc01..376b4cc 100644
--- a/net/batman-adv/routing.c
+++ b/net/batman-adv/routing.c
@@ -1124,8 +1124,14 @@
spin_unlock_bh(&orig_node->bcast_seqno_lock);
+ /* keep skb linear for crc calculation */
+ if (skb_linearize(skb) < 0)
+ goto out;
+
+ bcast_packet = (struct batadv_bcast_packet *)skb->data;
+
/* check whether this has been sent by another originator before */
- if (batadv_bla_check_bcast_duplist(bat_priv, bcast_packet, hdr_size))
+ if (batadv_bla_check_bcast_duplist(bat_priv, bcast_packet, skb->len))
goto out;
/* rebroadcast packet */