.TH "Mirror/redirect action in tc" 8 "11 Jan 2015" "iproute2" "Linux"

.SH NAME
mirred - mirror/redirect action
.SH SYNOPSIS
.in +8
.ti -8
.BR tc " ... " "action mirred"
.I DIRECTION ACTION
.RB "[ " index
.IR INDEX " ] "
.BI dev " DEVICENAME"

.ti -8
.IR DIRECTION " := { "
.BR ingress " | " egress " }"

.ti -8
.IR ACTION " := { "
.BR mirror " | " redirect " }"
.SH DESCRIPTION
The
.B mirred
action allows to redirect or mirror packets to another network interface on the
same system. It is typically used in combination with the
.B ifb
pseudo device to create a shrared instance where QoS happens, but serves well
for debugging or monitoring purposes, too.
.SH OPTIONS
.TP
.B ingress
.TQ
.B egress
Specify the direction in which the packet shall appear on the destination
interface. Currently only
.B egress
is implemented.
.TP
.B mirror
.TQ
.B redirect
Define whether the packet should be copied
.RB ( mirror )
or moved
.RB ( redirect )
to the destination interface.
.TP
.BI index " INDEX"
Assign a unique ID to this action instead of letting the kernel choose one
automatically.
.I INDEX
is a 32bit unsigned integer greater than zero.
.TP
.BI dev " DEVICENAME"
Specify the network interface to redirect or mirror to.
.SH EXAMPLES
Limit ingress bandwidth on eth0 to 1mbit/s, redirect exceeding traffic to lo for
debugging purposes:

.RS
.EX
# tc qdisc add dev eth0 handle ffff: ingress
# tc filter add dev eth0 parent ffff: u32 \\
	match u32 0 0 \\
	action police rate 1mbit burst 100k conform-exceed pipe \\
	action mirred egress redirect dev lo
.EE
.RE

Use an
.B ifb
interface to send ingress traffic on eth0 through an instance of
.BR sfq :

.RS
.EX
# modprobe ifb
# ip link set ifb0 up
# tc qdisc add dev ifb0 root sfq
# tc qdisc add dev eth0 handle ffff: ingress
# tc filter add dev eth0 parent ffff: u32 \\
	match u32 0 0 \\
	action mirred egress redirect dev ifb0
.EE
.RE

.SH SEE ALSO
.BR tc (8),
.BR tc-u32 (8)