Provided by: iproute2_5.2.0-1ubuntu2_amd64 bug


       tunnel_key - Tunnel metadata manipulation


       tc ... action tunnel_key { unset | SET }

       SET  :=  set  src_ip  ADDRESS dst_ip ADDRESS id KEY_ID dst_port UDP_PORT tos TOS ttl TTL [
               csum | nocsum ]


       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
       automatically  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 ).


       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 src_ip and  dst_ip
              options.  id , dst_port and geneve_opts are 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)

                     Outer header destination UDP port

                     Geneve  variable  length  options.   geneve_opts  is  specified  in the form
                     CLASS:TYPE:DATA, where CLASS is represented as a  16bit  hexadecimal  value,
                     TYPE  as an 8bit hexadecimal value and DATA as a variable length hexadecimal
                     value. Additionally multiple options may be listed using a comma delimiter.

              tos    Outer header TOS

              ttl    Outer header TTL

                     Controls 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

                     If  using  nocsum  with  IPv6, be sure you know what you are doing. Zero UDP
                     checksums provide weaker protection against corrupted packets.  See  RFC6935
                     for details.


       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



iproute2                                   10 Nov 201Tunnel metadata manipulation action in tc(8)