batman-adv: Add lower layer needed_(head|tail)room to own ones

The maximum of hard_header_len and maximum of all needed_(head|tail)room of
all slave interfaces of a batman-adv device must be used to define the
batman-adv device needed_(head|tail)room. This is required to avoid too
small buffer problems when these slave devices try to send the encapsulated
packet in a tx path without the possibility to resize the skbuff.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>

diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c
index 0565b20..f11345e 100644 (file)
--- a/net/batman-adv/hard-interface.c
+++ b/net/batman-adv/hard-interface.c
@@ -252,6 +252,44 @@ static void batadv_check_known_mac_addr(const struct net_device *net_dev)
        rcu_read_unlock();
 }
 
+/**
+ * batadv_hardif_recalc_extra_skbroom() - Recalculate skbuff extra head/tailroom
+ * @soft_iface: netdev struct of the mesh interface
+ */
+static void batadv_hardif_recalc_extra_skbroom(struct net_device *soft_iface)
+{
+       const struct batadv_hard_iface *hard_iface;
+       unsigned short lower_header_len = ETH_HLEN;
+       unsigned short lower_headroom = 0;
+       unsigned short lower_tailroom = 0;
+       unsigned short needed_headroom;
+
+       rcu_read_lock();
+       list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
+               if (hard_iface->if_status == BATADV_IF_NOT_IN_USE)
+                       continue;
+
+               if (hard_iface->soft_iface != soft_iface)
+                       continue;
+
+               lower_header_len = max_t(unsigned short, lower_header_len,
+                                        hard_iface->net_dev->hard_header_len);
+
+               lower_headroom = max_t(unsigned short, lower_headroom,
+                                      hard_iface->net_dev->needed_headroom);
+
+               lower_tailroom = max_t(unsigned short, lower_tailroom,
+                                      hard_iface->net_dev->needed_tailroom);
+       }
+       rcu_read_unlock();
+
+       needed_headroom = lower_headroom + (lower_header_len - ETH_HLEN);
+       needed_headroom += batadv_max_header_len();
+
+       soft_iface->needed_headroom = needed_headroom;
+       soft_iface->needed_tailroom = lower_tailroom;
+}
+
 int batadv_hardif_min_mtu(struct net_device *soft_iface)
 {
        struct batadv_priv *bat_priv = netdev_priv(soft_iface);
@@ -474,6 +512,8 @@ int batadv_hardif_enable_interface(struct batadv_hard_iface *hard_iface,
                           "Not using interface %s (retrying later): interface not active\n",
                           hard_iface->net_dev->name);
 
+       batadv_hardif_recalc_extra_skbroom(soft_iface);
+
        /* begin scheduling originator messages on that interface */
        batadv_schedule_bat_ogm(hard_iface);
 
@@ -529,6 +569,7 @@ void batadv_hardif_disable_interface(struct batadv_hard_iface *hard_iface,
        dev_put(hard_iface->soft_iface);
 
        netdev_upper_dev_unlink(hard_iface->net_dev, hard_iface->soft_iface);
+       batadv_hardif_recalc_extra_skbroom(hard_iface->soft_iface);
 
        /* nobody uses this interface anymore */
        if (!bat_priv->num_ifaces) {

diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c
index d5c5ad9..ac4d08d 100644 (file)
--- a/net/batman-adv/soft-interface.c
+++ b/net/batman-adv/soft-interface.c
@@ -947,8 +947,6 @@ static void batadv_softif_init_early(struct net_device *dev)
         * have not been initialized yet
         */
        dev->mtu = ETH_DATA_LEN;
-       /* reserve more space in the skbuff for our header */
-       dev->hard_header_len = batadv_max_header_len();
 
        /* generate random address */
        eth_hw_addr_random(dev);