Commit 7f112af4 authored by Linus Lüssing's avatar Linus Lüssing Committed by Antonio Quartulli
Browse files

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: default avatarLinus Lüssing <linus.luessing@web.de>
Acked-by: default avatarSimon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: default avatarMarek Lindner <lindner_marek@yahoo.de>
parent 43c422ed

net/batman-adv/bridge_loop_avoidance.c

+4 −4
Original line number Diff line number Diff line
@@ -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);

net/batman-adv/routing.c

+7 −1
Original line number Diff line number Diff line
@@ -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 */

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