tc-csum(8) - phpMan

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 com-
       monly used to fix incorrect checksums after the pedit action has modified the packet  con-
       tent.

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 destina-
       tion 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)

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