net: gre: use icmp_hdr() to get inner ip header
[ Upstream commit
c0c0c50ff7c3e331c90bab316d21f724fb9e1994 ]
When dealing with icmp messages, the skb->data points the
ip header that triggered the sending of the icmp message.
In gre_cisco_err(), the parse_gre_header() is called, and the
iptunnel_pull_header() is called to pull the skb at the end of
the parse_gre_header(), so the skb->data doesn't point the
inner ip header.
Unfortunately, the ipgre_err still needs those ip addresses in
inner ip header to look up tunnel by ip_tunnel_lookup().
So just use icmp_hdr() to get inner ip header instead of skb->data.
Signed-off-by: Duan Jiong <duanj.fnst@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>