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   csum    ( 8 )

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Имя (Name)

csum - checksum update action

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Синопсис (Synopsis)

tc ... action csum UPDATE

UPDATE := TARGET [ UPDATE ]

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

SWEETS := { and | or | + }

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Описание (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.

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Параметры (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.

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Примеры (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

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Смотри также (See also)

tc(8), tc-pedit(8)

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