drivers/net/wan/lapbether: Make skb->protocol consistent with the header

[ Upstream commit 83f9a9c8c1edc222846dc1bde6e3479703e8e5a3 ]

This driver is a virtual driver stacked on top of Ethernet interfaces.

When this driver transmits data on the Ethernet device, the skb->protocol
setting is inconsistent with the Ethernet header prepended to the skb.

This causes a user listening on the Ethernet interface with an AF_PACKET
socket, to see different sll_protocol values for incoming and outgoing
frames, because incoming frames would have this value set by parsing the
Ethernet header.

This patch changes the skb->protocol value for outgoing Ethernet frames,
making it consistent with the Ethernet header prepended. This makes a
user listening on the Ethernet device with an AF_PACKET socket, to see
the same sll_protocol value for incoming and outgoing frames.

Cc: Martin Schiller <ms@dev.tdt.de>
Signed-off-by: Xie He <xie.he.0141@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/net/wan/lapbether.c b/drivers/net/wan/lapbether.c
index c6db9a4e7c457b4d76f3142943d12eb14932e649..ef746ba74ab4c6a7e4fd8054080999e01740cafd 100644 (file)
--- a/drivers/net/wan/lapbether.c
+++ b/drivers/net/wan/lapbether.c
@@ -201,8 +201,6 @@ static void lapbeth_data_transmit(struct net_device *ndev, struct sk_buff *skb)
        struct net_device *dev;
        int size = skb->len;
 
-       skb->protocol = htons(ETH_P_X25);
-
        ptr = skb_push(skb, 2);
 
        *ptr++ = size % 256;
@@ -213,6 +211,8 @@ static void lapbeth_data_transmit(struct net_device *ndev, struct sk_buff *skb)
 
        skb->dev = dev = lapbeth->ethdev;
 
+       skb->protocol = htons(ETH_P_DEC);
+
        skb_reset_network_header(skb);
 
        dev_hard_header(skb, dev, ETH_P_DEC, bcast_addr, NULL, 0);