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.
decode For the receiving side; decode the metadata if the packet
encode For the sending side. Encode the specified metadata if the
allow Encode direction only. Allows encoding specified metadata.
use Encode direction only. Enforce static encoding of specified
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
u16_value ] Value to set for the traffic control index in the
skb structure. The u16 value is required only when use is
dmac DMACsmac SMAC
Optional six byte destination or source MAC address to encode.
Optional 16-bit ethertype to encode. If not specified value of
0xED3E will be used.
Action to take following an encode/decode.
Assign a unique ID to this action instead of letting the
kernel choose one automatically. INDEX is a 32bit unsigned
integer greater than zero.
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 \
Match with skb mark of 17:
# tc filter add dev eth0 parent ffff: prio 4 protocol ip \
handle 0x11 fw flowid 1:1 \
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 packaet with ethertype 0xdead, add
skb->mark to whitelist of metadatum to send, and rewrite the destina‐
tion 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 \
This page is part of the iproute2 (utilities for controlling TCP/IP
networking and traffic) project. Information about the project can
be found at
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email@example.com, firstname.lastname@example.org. This page was obtained
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iproute2 22 Apr 2016 IFE action in tc(8)