diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c
index 004017c523fa501bfb06446a11df15e58575b632..d564af295db438a399ef5eac70844e34e1aced21 100644
--- a/net/batman-adv/hard-interface.c
+++ b/net/batman-adv/hard-interface.c
@@ -269,9 +269,10 @@ int batadv_hardif_min_mtu(struct net_device *soft_iface)
const struct batadv_priv *bat_priv = netdev_priv(soft_iface);
const struct batadv_hard_iface *hard_iface;
/* allow big frames if all devices are capable to do so
- * (have MTU > 1500 + BAT_HEADER_LEN)
+ * (have MTU > 1500 + batadv_max_header_len())
*/
int min_mtu = ETH_DATA_LEN;
+ int max_header_len = batadv_max_header_len();
if (atomic_read(&bat_priv->fragmentation))
goto out;
@@ -285,8 +286,7 @@ int batadv_hardif_min_mtu(struct net_device *soft_iface)
if (hard_iface->soft_iface != soft_iface)
continue;
- min_mtu = min_t(int,
- hard_iface->net_dev->mtu - BATADV_HEADER_LEN,
+ min_mtu = min_t(int, hard_iface->net_dev->mtu - max_header_len,
min_mtu);
}
rcu_read_unlock();
@@ -380,6 +380,7 @@ int batadv_hardif_enable_interface(struct batadv_hard_iface *hard_iface,
struct batadv_priv *bat_priv;
struct net_device *soft_iface, *master;
__be16 ethertype = htons(ETH_P_BATMAN);
+ int max_header_len = batadv_max_header_len();
int ret;
if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
@@ -448,18 +449,18 @@ int batadv_hardif_enable_interface(struct batadv_hard_iface *hard_iface,
hard_iface->net_dev->name);
if (atomic_read(&bat_priv->fragmentation) &&
- hard_iface->net_dev->mtu < ETH_DATA_LEN + BATADV_HEADER_LEN)
+ hard_iface->net_dev->mtu < ETH_DATA_LEN + max_header_len)
batadv_info(hard_iface->soft_iface,
- "The MTU of interface %s is too small (%i) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to %zi would solve the problem.\n",
+ "The MTU of interface %s is too small (%i) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to %i would solve the problem.\n",
hard_iface->net_dev->name, hard_iface->net_dev->mtu,
- ETH_DATA_LEN + BATADV_HEADER_LEN);
+ ETH_DATA_LEN + max_header_len);
if (!atomic_read(&bat_priv->fragmentation) &&
- hard_iface->net_dev->mtu < ETH_DATA_LEN + BATADV_HEADER_LEN)
+ hard_iface->net_dev->mtu < ETH_DATA_LEN + max_header_len)
batadv_info(hard_iface->soft_iface,
- "The MTU of interface %s is too small (%i) to handle the transport of batman-adv packets. If you experience problems getting traffic through try increasing the MTU to %zi.\n",
+ "The MTU of interface %s is too small (%i) to handle the transport of batman-adv packets. If you experience problems getting traffic through try increasing the MTU to %i.\n",
hard_iface->net_dev->name, hard_iface->net_dev->mtu,
- ETH_DATA_LEN + BATADV_HEADER_LEN);
+ ETH_DATA_LEN + max_header_len);
if (batadv_hardif_is_iface_up(hard_iface))
batadv_hardif_activate_interface(hard_iface);
diff --git a/net/batman-adv/main.c b/net/batman-adv/main.c
index 519138e32fe6157ab214e5568b1e01cec14a6942..7f3a5c426615788b4565dcd86bf06c2e34e7627e 100644
--- a/net/batman-adv/main.c
+++ b/net/batman-adv/main.c
@@ -255,6 +255,31 @@ batadv_seq_print_text_primary_if_get(struct seq_file *seq)
return primary_if;
}
+/**
+ * batadv_max_header_len - calculate maximum encapsulation overhead for a
+ * payload packet
+ *
+ * Return the maximum encapsulation overhead in bytes.
+ */
+int batadv_max_header_len(void)
+{
+ int header_len = 0;
+
+ header_len = max_t(int, header_len,
+ sizeof(struct batadv_unicast_packet));
+ header_len = max_t(int, header_len,
+ sizeof(struct batadv_unicast_4addr_packet));
+ header_len = max_t(int, header_len,
+ sizeof(struct batadv_bcast_packet));
+
+#ifdef CONFIG_BATMAN_ADV_NC
+ header_len = max_t(int, header_len,
+ sizeof(struct batadv_coded_packet));
+#endif
+
+ return header_len;
+}
+
/**
* batadv_skb_set_priority - sets skb priority according to packet content
* @skb: the packet to be sent
diff --git a/net/batman-adv/main.h b/net/batman-adv/main.h
index 6a74a42253263d92c01fba35b4a9321ece74a43e..54c13d51edbeee58dcf04e2e03fa718d8cd06555 100644
--- a/net/batman-adv/main.h
+++ b/net/batman-adv/main.h
@@ -191,6 +191,7 @@ void batadv_mesh_free(struct net_device *soft_iface);
int batadv_is_my_mac(struct batadv_priv *bat_priv, const uint8_t *addr);
struct batadv_hard_iface *
batadv_seq_print_text_primary_if_get(struct seq_file *seq);
+int batadv_max_header_len(void);
void batadv_skb_set_priority(struct sk_buff *skb, int offset);
int batadv_batman_skb_recv(struct sk_buff *skb, struct net_device *dev,
struct packet_type *ptype,
diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c
index 87e7e4ed216d6820d452594e42b02dfd6e43db71..15c7237f427b6ae31abb27f1670826cc3ca2d0b9 100644
--- a/net/batman-adv/soft-interface.c
+++ b/net/batman-adv/soft-interface.c
@@ -626,7 +626,7 @@ 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_HEADER_LEN;
+ dev->hard_header_len = batadv_max_header_len();
/* generate random address */
eth_hw_addr_random(dev);
diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
index d517d5dde6adfdbe2dba226f4b6ff5be7e8e8e13..5cbb0d09a9b58519dfc17bd59f857710622e2d95 100644
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -24,13 +24,6 @@
#include "bitarray.h"
#include <linux/kernel.h>
-/**
- * Maximum overhead for the encapsulation for a payload packet
- */
-#define BATADV_HEADER_LEN \
- (ETH_HLEN + max(sizeof(struct batadv_unicast_packet), \
- sizeof(struct batadv_bcast_packet)))
-
#ifdef CONFIG_BATMAN_ADV_DAT
/* batadv_dat_addr_t is the type used for all DHT addresses. If it is changed,