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Included fixes:

Browse source 
- Fix broadcast packet CRC calculation which can lead to ~80% broadcast packet
   loss
 - Fix a race condition in duplicate broadcast packet check
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Merge tag 'batman-adv-fix-for-davem' of git://git.open-mesh.org/linux-merge

Included fixes:
- Fix broadcast packet CRC calculation which can lead to ~80% broadcast packet
  loss
- Fix a race condition in duplicate broadcast packet check

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2012-10-18 15:36:59 -04:00
commit db0fe0b2f6
3 changed files with 27 additions and 10 deletions
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27
net/batman-adv/bridge_loop_avoidance.c
View file

@ -1167,6 +1167,8 @@ int batadv_bla_init(struct batadv_priv *bat_priv)
uint16_t crc;
unsigned long entrytime;
spin_lock_init(&bat_priv->bla.bcast_duplist_lock);
batadv_dbg(BATADV_DBG_BLA, bat_priv, "bla hash registering\n");
/* setting claim destination address */
@ -1210,8 +1212,8 @@ 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,
@ -1224,20 +1226,22 @@ 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;
int i, length, curr, ret = 0;
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);
/* calculate the crc ... */
crc = crc16(0, content, length);
spin_lock_bh(&bat_priv->bla.bcast_duplist_lock);
for (i = 0; i < BATADV_DUPLIST_SIZE; i++) {
curr = (bat_priv->bla.bcast_duplist_curr + i);
curr %= BATADV_DUPLIST_SIZE;
@ -1259,9 +1263,12 @@ int batadv_bla_check_bcast_duplist(struct batadv_priv *bat_priv,
/* this entry seems to match: same crc, not too old,
* and from another gw. therefore return 1 to forbid it.
*/
return 1;
ret = 1;
goto out;
}
/* not found, add a new entry (overwrite the oldest entry) */
/* not found, add a new entry (overwrite the oldest entry)
* and allow it, its the first occurence.
*/
curr = (bat_priv->bla.bcast_duplist_curr + BATADV_DUPLIST_SIZE - 1);
curr %= BATADV_DUPLIST_SIZE;
entry = &bat_priv->bla.bcast_duplist[curr];
@ -1270,8 +1277,10 @@ int batadv_bla_check_bcast_duplist(struct batadv_priv *bat_priv,
memcpy(entry->orig, bcast_packet->orig, ETH_ALEN);
bat_priv->bla.bcast_duplist_curr = curr;
/* allow it, its the first occurence. */
return 0;
out:
spin_unlock_bh(&bat_priv->bla.bcast_duplist_lock);
return ret;
}

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 */

2
net/batman-adv/types.h
View file

@ -205,6 +205,8 @@ struct batadv_priv_bla {
struct batadv_hashtable *backbone_hash;
struct batadv_bcast_duplist_entry bcast_duplist[BATADV_DUPLIST_SIZE];
int bcast_duplist_curr;
/* protects bcast_duplist and bcast_duplist_curr */
spinlock_t bcast_duplist_lock;
struct batadv_bla_claim_dst claim_dest;
struct delayed_work work;
};