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>
This commit is contained in:
Xie He 2020-09-16 09:49:18 -07:00 committed by Greg Kroah-Hartman
parent 89fd103fbb
commit 3ba3fc3e7e

View File

@ -198,8 +198,6 @@ 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;
@ -210,6 +208,8 @@ 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);