csum - checksum update action

       The  csum  action triggers checksum recalculation of specified packet headers. It is commonly used to fix
       incorrect checksums after the pedit action has modified the packet content.

       The  following  performs  stateless  NAT  for  incoming  packets  from  192.0.2.100  to  new  destination
       198.51.100.1. Assuming these are UDP packets, both IP and UDP checksums have to be recalculated:

              # tc qdisc add dev eth0 ingress handle ffff:
              # tc filter add dev eth0 prio 1 protocol ip parent ffff: \
                   u32 match ip src 192.0.2.100/32 flowid :1 \
                   action pedit munge ip dst set 198.51.100.1 pipe \
                   csum ip and udp

       csum - checksum update action

TARGET Specify which headers to update: IPv4 header (ip4h), ICMP header (icmp), IGMP header  (igmp),  TCP
              header (tcp), UDP header (udp), UDPLite header (udplite) or SCTP header (sctp).

       SWEETS These are merely syntactic sugar and ignored internally.

tc(8), tc-pedit(8)

iproute2                                           11 Jan 2015                          Checksumactionintc(8)

tc ... actioncsumUPDATEUPDATE := TARGET [ UPDATE ]

       TARGET := { ip4h | icmp | igmp | tcp | udp | udplite | sctp | SWEETS }

       SWEETS := { and | or | + }