The NAT checksum fixes in patches/linux-2.6.16-rc2/net-csum.patch do

The NAT checksum fixes in patches/linux-2.6.16-rc2/net-csum.patch do
not work when port numbers are modified (bug 447).
tcp_manip_pkt()/udp_manip_pkt() modify the protocol checksum to
reflect the changes to ip addresses and port numbers.  When
dev_queue_xmit() finds a message with proto_csum_blank set, it
calculates a new tcp/udp checksum that includes both the modified port
numbers and the modified protocol checksum field...  so the change to
the port numbers affects the protocol checksum twice.

This patch modifies net-csum.patch to remove the checksum mangling for
port numbers in tcp_manip_pkt()/udp_manip_pkt()

Signed-off-by: Jim Dykman <dykman@us.ibm.com>