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tc-csum(8) [osx man page]

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

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 to new destination 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 flowid :1 action pedit munge ip dst set 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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Tunnel metadata manipulation action in tc(8)			       Linux			      Tunnel metadata manipulation action in tc(8)

tunnel_key - Tunnel metadata manipulation SYNOPSIS
tc ... action tunnel_key { unset | SET } SET := set src_ip ADDRESS dst_ip ADDRESS id KEY_ID dst_port UDP_PORT [ csum | nocsum ] DESCRIPTION
The tunnel_key action combined with a shared IP tunnel device, allows to perform IP tunnel en- or decapsulation on a packet, reflected by the operation modes UNSET and SET. The UNSET mode is optional - even without using it, the metadata information will be released automati- cally when packet processing will be finished. UNSET function could be used in cases when traffic is forwarded between two tunnels, where the metadata from the first tunnel will be used for encapsulation done by the second tunnel. SET mode requires the source and destination ip ADDRESS and the tunnel key id KEY_ID which will be used by the ip tunnel shared device to create the tunnel header. The tunnel_key action is useful only in combination with a mirred redirect action to a shared IP tunnel device which will use the metadata (for SET ) and unset the metadata created by it (for UNSET ). OPTIONS
unset Unset the tunnel metadata created by the IP tunnel device. This function is not mandatory and might be used only in some specific use cases (as explained above). set Set tunnel metadata to be used by the IP tunnel device. Requires id , src_ip and dst_ip options. dst_port is optional. id Tunnel ID (for example VNI in VXLAN tunnel) src_ip Outer header source IP address (IPv4 or IPv6) dst_ip Outer header destination IP address (IPv4 or IPv6) dst_port Outer header destination UDP port [no]csum Controlls outer UDP checksum. When set to csum (which is default), the outer UDP checksum is calculated and included in the packets. When set to nocsum, outer UDP checksum is zero. Note that when using zero UDP checksums with IPv6, the other tunnel endpoint must be configured to accept such packets. In Linux, this would be the udp6zerocsumrx option for the VXLAN tunnel interface. If using nocsum with IPv6, be sure you know what you are doing. Zero UDP checksums provide weaker protection against cor- rupted packets. See RFC6935 for details. EXAMPLES
The following example encapsulates incoming ICMP packets on eth0 into a vxlan tunnel, by setting metadata to VNI 11, source IP and destination IP, and by redirecting the packet with the metadata to device vxlan0, which will do the actual encapsulation using the metadata: #tc qdisc add dev eth0 handle ffff: ingress #tc filter add dev eth0 protocol ip parent ffff: flower ip_proto icmp action tunnel_key set src_ip dst_ip id 11 action mirred egress redirect dev vxlan0 Here is an example of the unset function: Incoming VXLAN traffic with outer IP's and VNI 11 is decapsulated by vxlan0 and metadata is unset before redirecting to tunl1 device: #tc qdisc add dev eth0 handle ffff: ingress #tc filter add dev vxlan0 protocol ip parent ffff: flower enc_src_ip enc_dst_ip enc_key_id 11 action tunnel_key unset action mirred egress redirect dev tunl1 SEE ALSO
tc(8) iproute2 10 Nov 2016 Tunnel metadata manipulation action in tc(8)
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