batman-adv: use vlan_/eth_hdr() instead of skb->data in interface_tx path

Our .ndo_start_xmit handler (batadv_interface_tx()) can rely on having
the skb mac header pointer set correctly since the following commit
present in kernels >= 3.9:

"net: reset mac header in dev_start_xmit()" (6d1ccff627)

Therefore we can safely use eth_hdr() and vlan_eth_hdr() instead of
skb->data now, which spares us some ugly type casts.

At the same time set the mac_header in batadv_dat_snoop_incoming_arp_request()
before sending the skb along the TX path.

Signed-off-by: Linus Lüssing <linus.luessing@web.de>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>

1 files changed, 5 insertions, 6 deletions

diff --git a/net/batman-adv/send.c b/net/batman-adv/send.c
index 843febd1e519..1703a2ef72a9 100644
--- a/net/batman-adv/send.c
+++ b/net/batman-adv/send.c
@@ -256,7 +256,7 @@ static int batadv_send_skb_unicast(struct batadv_priv *bat_priv,
 {
         struct ethhdr *ethhdr;
         struct batadv_unicast_packet *unicast_packet;
-        int ret = NET_XMIT_DROP, hdr_size;
+        int ret = NET_XMIT_DROP;
 
         if (!orig_node)
                 goto out;
@@ -265,16 +265,12 @@ static int batadv_send_skb_unicast(struct batadv_priv *bat_priv,
         case BATADV_UNICAST:
                 if (!batadv_send_skb_prepare_unicast(skb, orig_node))
                         goto out;
-
-                hdr_size = sizeof(*unicast_packet);
                 break;
         case BATADV_UNICAST_4ADDR:
                 if (!batadv_send_skb_prepare_unicast_4addr(bat_priv, skb,
                                                            orig_node,
                                                            packet_subtype))
                         goto out;
-
-                hdr_size = sizeof(struct batadv_unicast_4addr_packet);
                 break;
         default:
                 /* this function supports UNICAST and UNICAST_4ADDR only. It
@@ -283,7 +279,10 @@ static int batadv_send_skb_unicast(struct batadv_priv *bat_priv,
                 goto out;
         }
 
-        ethhdr = (struct ethhdr *)(skb->data + hdr_size);
+        /* skb->data might have been reallocated by
+         * batadv_send_skb_prepare_unicast{,_4addr}()
+         */
+        ethhdr = eth_hdr(skb);
         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 
         /* inform the destination node that we are still missing a correct route