Manual: tc-csum

Checksum action in tc(8)			    Linux			    Checksum action in tc(8)

NAME
       csum - checksum update action

SYNOPSIS
       tc ... action csum UPDATE

       UPDATE := TARGET [ UPDATE ]

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

       SWEETS := { and | or | + }

DESCRIPTION
       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.

OPTIONS
       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.

EXAMPLES
       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

SEE ALSO
       tc(8), tc-pedit(8)

iproute2					 11 Jan 2015			    Checksum action in tc(8)