net/tap: fix Rx checksum flags on TCP packets
net/tap: fix Rx checksum flags on TCP packets

Since commit d5df2ae0428a ("net: fix unneeded replacement of TCP
checksum 0"), the functions rte_ipv4_udptcp_cksum() or
rte_ipv6_udptcp_cksum() can return either 0x0000 or 0xffff when used to
verify a packet containing a valid checksum.

This new behavior broke the checksum verification in tap driver for TCP
packets: these packets are marked with PKT_RX_L4_CKSUM_BAD.

Fix this by checking the 2 possible values. A next commit will introduce
a checksum verification helper to simplify this a bit.

Fixes: d5df2ae0428a ("net: fix unneeded replacement of TCP checksum 0")
Cc: stable@dpdk.org

Signed-off-by: Olivier Matz <dfcc1510895413197abb4336e39bb0a3906cba71@6wind.com>
Acked-by: Andrew Rybchenko <4155e7bf8e0185127625dac6d84336299844982f@oktetlabs.ru>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk