# tc-ife

## NAME



           IFE - encapsulate/decapsulate metadata
    


## SYNOPSIS



           **tc**...  **action ife** _DIRECTION_ [ _ACTION_ ] [ **dst** _DMAC_ ] [ **src** _SMAC_ ]
                   [ **type** _TYPE_ ] [ _CONTROL_ ] [ **index** _INDEX_ ]
    
           _DIRECTION_ := { **decode** | **encode**}
    
           _ACTION_ := { **allow** _ATTR_ | **use** _ATTR value_ }
    
           _ATTR_ := { **mark** | **prio** | **tcindex**}
    
           _CONTROL_ := { **reclassify** | **use** | **pipe** | **drop** | **continue** | **ok** | **goto**
                   **chain CHAIN_INDEX**}
    


## DESCRIPTION



           The **ife** action allows for a sending side to encapsulate arbitrary
           metadata, which is then decapsulated by the receiving end. The
           sender runs in encoding mode and the receiver in decode mode. Both
           sender and receiver must specify the same ethertype. In the
           future, a registered ethertype may be available as a default.
    


## OPTIONS



           **decode** For the receiving side; decode the metadata if the packet
                  matches.
    
           **encode** For the sending side. Encode the specified metadata if the
                  packet matches.
    
           **allow** Encode direction only. Allows encoding specified metadata.
    
           **use** Encode direction only. Enforce static encoding of specified
                  metadata.
    
           **mark**[ _u32_value_ ] The value to set for the skb mark. The u32
                  value is required only when **use** is specified. If **mark** value
                  is zero, it will not be encoded, instead "overlimits"
                  statistics increment and **CONTROL** action is taken.
    
           **prio**[ _u32_value_ ] The value to set for priority in the skb
                  structure. The u32 value is required only when **use** is
                  specified.
    
           **tcindex**[
                  _u16_value_ ] Value to set for the traffic control index in
                  the skb structure. The u16 value is required only when **use**
                  is specified.
    
           **dmac** _DMAC_
           **smac** _SMAC_
                  Optional six byte destination or source MAC address to
                  encode.
    
           **type** _TYPE_
                  Optional 16-bit ethertype to encode. If not specified value
                  of 0xED3E will be used.
    
           **CONTROL**
                  Action to take following an encode/decode.
    
           **index** _INDEX_
                  Assign a unique ID to this action instead of letting the
                  kernel choose one automatically.  _INDEX_ is a 32bit unsigned
                  integer greater than zero.
    


## EXAMPLES



           On the receiving side, match packets with ethertype 0xdead and
           restart classification so that it will match ICMP on the next
           rule, at prio 3:
                  # tc qdisc add dev eth0 handle ffff: ingress
                  # tc filter add dev eth0 parent ffff: prio 2 protocol 0xdead \
                       u32 match u32 0 0 flowid 1:1 \
                       action ife decode reclassify
                  # tc filter add dev eth0 parent ffff: prio 3 protocol ip \
                       u32 match ip protocol 0xff flowid 1:1 \
                       action continue
    
           Match with skb mark of 17:
    
                  # tc filter add dev eth0 parent ffff: prio 4 protocol ip \
                       handle 0x11 fw flowid 1:1 \
                       action ok
    
           Configure the sending side to encode for the filters above. Use a
           destination IP address of 192.168.122.237/24, then tag with skb
           mark of decimal 17. Encode the packet with ethertype 0xdead, add
           skb->mark to allowed list of meta datum to send, and rewrite the
           destination MAC address to 02:15:15:15:15:15.
    
                  # tc qdisc add dev eth0 root handle 1: prio
                  # tc filter add dev eth0 parent 1: protocol ip prio 10 u32 \
                       match ip dst 192.168.122.237/24 \
                       match ip protocol 1 0xff \
                       flowid 1:2 \
                       action skbedit mark 17 \
                       action ife encode \
                       type 0xDEAD \
                       allow mark \
                       dst 02:15:15:15:15:15
    


* * *