batman-adv: Reserve extra bytes in skb for better alignment

The ethernet header is 14 bytes long. Therefore, the data after it is not 4
byte aligned and may cause problems on systems without unaligned data access.
Reserving NET_IP_ALIGN more byes can fix the misalignment of the ethernet
header.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>

1 files changed, 5 insertions, 3 deletions

diff --git a/net/batman-adv/bat_iv_ogm.c b/net/batman-adv/bat_iv_ogm.c
index 75403a491892..9f3925a85aab 100644
--- a/net/batman-adv/bat_iv_ogm.c
+++ b/net/batman-adv/bat_iv_ogm.c
@@ -411,9 +411,11 @@ static void batadv_iv_ogm_aggregate_new(const unsigned char *packet_buff,
 
         if ((atomic_read(&bat_priv->aggregated_ogms)) &&
             (packet_len < BATADV_MAX_AGGREGATION_BYTES))
-                skb_size = BATADV_MAX_AGGREGATION_BYTES + ETH_HLEN;
+                skb_size = BATADV_MAX_AGGREGATION_BYTES;
         else
-                skb_size = packet_len + ETH_HLEN;
+                skb_size = packet_len;
+
+        skb_size += ETH_HLEN + NET_IP_ALIGN;
 
         forw_packet_aggr->skb = dev_alloc_skb(skb_size);
         if (!forw_packet_aggr->skb) {
@@ -422,7 +424,7 @@ static void batadv_iv_ogm_aggregate_new(const unsigned char *packet_buff,
                 kfree(forw_packet_aggr);
                 goto out;
         }
-        skb_reserve(forw_packet_aggr->skb, ETH_HLEN);
+        skb_reserve(forw_packet_aggr->skb, ETH_HLEN + NET_IP_ALIGN);
 
         INIT_HLIST_NODE(&forw_packet_aggr->list);