The size of the TCP header is miscalculated when the window scale ends
up being 0. Additionally, this can be induced by sending a SYN to a
passive open port with a window scale option with value 0.
Signed-off-by: NPhilip Love <love_phil@emc.com>
Signed-off-by: NAdam Langley <agl@imperialviolet.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>