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batman-adv: Fix broadcast packet CRC calculation

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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>
This commit is contained in:
Linus Lüssing 2012-10-17 14:53:04 +02:00 committed by Antonio Quartulli
parent 43c422eda9
commit 7f112af40f
2 changed files with 11 additions and 5 deletions
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8
net/batman-adv/bridge_loop_avoidance.c
View file

@ -1210,8 +1210,8 @@ int batadv_bla_init(struct batadv_priv *bat_priv)
/**
* 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_init(struct batadv_priv *bat_priv)
*/
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);

8
net/batman-adv/routing.c
View file

@ -1124,8 +1124,14 @@ int batadv_recv_bcast_packet(struct sk_buff *skb,
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 */