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batman-adv: fix soft-interface MTU computation

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The current MTU computation always returns a value
smaller than 1500bytes even if the real interfaces
have an MTU large enough to compensate the batman-adv
overhead.

Fix the computation by properly returning the highest
admitted value.

Introduced by a19d3d85e1
("batman-adv: limit local translation table max size")

Reported-by: Russell Senior <russell@personaltelco.net>
Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
This commit is contained in:
Antonio Quartulli 2014-01-21 11:22:05 +01:00
parent 0fd5d57ba3
commit 930cd6e46e
1 changed files with 14 additions and 8 deletions
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22
net/batman-adv/hard-interface.c
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@ -241,7 +241,7 @@ int batadv_hardif_min_mtu(struct net_device *soft_iface)
{
struct batadv_priv *bat_priv = netdev_priv(soft_iface);
const struct batadv_hard_iface *hard_iface;
int min_mtu = ETH_DATA_LEN;
int min_mtu = INT_MAX;
rcu_read_lock();
list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
@ -256,8 +256,6 @@ int batadv_hardif_min_mtu(struct net_device *soft_iface)
}
rcu_read_unlock();
atomic_set(&bat_priv->packet_size_max, min_mtu);
if (atomic_read(&bat_priv->fragmentation) == 0)
goto out;
@ -268,13 +266,21 @@ int batadv_hardif_min_mtu(struct net_device *soft_iface)
min_mtu = min_t(int, min_mtu, BATADV_FRAG_MAX_FRAG_SIZE);
min_mtu -= sizeof(struct batadv_frag_packet);
min_mtu *= BATADV_FRAG_MAX_FRAGMENTS;
atomic_set(&bat_priv->packet_size_max, min_mtu);
/* with fragmentation enabled we can fragment external packets easily */
min_mtu = min_t(int, min_mtu, ETH_DATA_LEN);
out:
return min_mtu - batadv_max_header_len();
/* report to the other components the maximum amount of bytes that
* batman-adv can send over the wire (without considering the payload
* overhead). For example, this value is used by TT to compute the
* maximum local table table size
*/
atomic_set(&bat_priv->packet_size_max, min_mtu);
/* the real soft-interface MTU is computed by removing the payload
* overhead from the maximum amount of bytes that was just computed.
*
* However batman-adv does not support MTUs bigger than ETH_DATA_LEN
*/
return min_t(int, min_mtu - batadv_max_header_len(), ETH_DATA_LEN);
}
/* adjusts the MTU if a new interface with a smaller MTU appeared. */