This fix is for IPv6 checksum offload error on RHEL65. Any optimalisation above -O0 provide error in IPv6 checksum flag "-fstrict-aliasing" is default for optimalisation above -O0. The solution is to add typedef with __attribute__((__may_alias__) for uint16_t.
Step 1 : start testpmd ./testpmd -c 0x6 -n 4 -- -i --portmask=0x3 --disable-hw-vlan --enable-rx-cksum --crc-strip --txqflags=0 Step 2 : settings and start set verbose 1 set fwd csum start Step 3 : send scapy with bad checksum IPv6/TCP packet Ether(src="52:00:00:00:00:00", dst="90:e2:ba:4a:33:5d")/IPv6(src="::1")/TCP(chksum=0xf)/("X"*46) Step 4 : Recieved packets: RESULTS: IPv6/TCP': ['0xd41'] or other unexpected. EXPECTED RESULTS: IPv6/TCP': ['0x9f5e'] Daniel Mrzyglod (1): net: fix build with gcc 4.4.7 and strict aliasing lib/librte_net/rte_ip.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) -- 2.5.0