The maximum of hard_header_len and needed_headroom of all slave interfaces of a batman-adv device must be used to define the batman-adv device headroom/header_len. This is required to avoid too small headroom problems when these slave devices try to send the encapsulated packet.

The batman-adv therefore uses:

needed_headroom = max(0, dev[0].needed_headroom, ..., dev[n].needed_headroom) hard_header_len = max(ETH_HLEN, dev[0].hard_header_len, ..., dev[n].hard_header_len) + ETH_HLEN + max(sizeof(batadv_*cast_packet))

Signed-off-by: Sven Eckelmann sven@narfation.org --- net/batman-adv/hard-interface.c | 33 +++++++++++++++++++++++++++++++++ net/batman-adv/soft-interface.c | 2 +- 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c index f4a15d2e5eaf..a501aae1077b 100644 --- a/net/batman-adv/hard-interface.c +++ b/net/batman-adv/hard-interface.c @@ -252,12 +252,45 @@ static void batadv_check_known_mac_addr(const struct net_device *net_dev) rcu_read_unlock(); }

+/** + * batadv_hardif_recalc_headroom() - Recalculate skbuff headroom parameters + * @soft_iface: netdev struct of the mesh interface + */ +static void batadv_hardif_recalc_headroom(struct net_device *soft_iface) +{ + const struct batadv_hard_iface *hard_iface; + unsigned short hard_header_len = ETH_HLEN; + unsigned short needed_headroom = 0; + + rcu_read_lock(); + list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) { + if ((hard_iface->if_status != BATADV_IF_ACTIVE) && + (hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED)) + continue; + + if (hard_iface->soft_iface != soft_iface) + continue; + + hard_header_len = max_t(unsigned short, hard_header_len, + hard_iface->net_dev->hard_header_len); + + needed_headroom = max_t(unsigned short, needed_headroom, + hard_iface->net_dev->needed_headroom); + } + rcu_read_unlock(); + + soft_iface->needed_headroom = needed_headroom; + soft_iface->hard_header_len = hard_header_len + batadv_max_header_len(); +} + 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 = INT_MAX;

+ batadv_hardif_recalc_headroom(soft_iface); + rcu_read_lock(); list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) { if ((hard_iface->if_status != BATADV_IF_ACTIVE) && diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c index 36b23f31df2a..b4c110791203 100644 --- a/net/batman-adv/soft-interface.c +++ b/net/batman-adv/soft-interface.c @@ -948,7 +948,7 @@ static void batadv_softif_init_early(struct net_device *dev) */ dev->mtu = ETH_DATA_LEN; /* reserve more space in the skbuff for our header */ - dev->hard_header_len = batadv_max_header_len(); + dev->hard_header_len = ETH_HLEN + batadv_max_header_len();

/* generate random address */ eth_hw_addr_random(dev);