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MPLS manipulation action in tc(8) Linux MPLS manipulation action in tc(8)
NAME
mpls - mpls manipulation module
SYNOPSIS
tc ... action mpls { POP | PUSH | MODIFY | dec_ttl } [ CONTROL ]
POP := pop protocol MPLS_PROTO
PUSH := { push | mac_push } [ protocol MPLS_PROTO ] [ tc MPLS_TC ] [ ttl MPLS_TTL ] [
bos MPLS_BOS ] label MPLS_LABEL
MODIFY := modify [ label MPLS_LABEL ] [ tc MPLS_TC ] [ ttl MPLS_TTL ]
CONTROL := { reclassify | pipe | drop | continue | pass | goto chain CHAIN_INDEX }
DESCRIPTION
The mpls action performs mpls encapsulation or decapsulation on a packet, reflected by the
operation modes POP, PUSH, MODIFY and DEC_TTL. The POP mode requires the ethertype of the
header that follows the MPLS header (e.g. IPv4 or another MPLS). It will remove the outer
MPLS header and replace the ethertype in the MAC header with that passed. The PUSH and
MODIFY modes update the current MPLS header information or add a new header. PUSH re-
quires at least an MPLS_LABEL. DEC_TTL requires no arguments and simply subtracts 1 from
the MPLS header TTL field.
OPTIONS
pop Decapsulation mode. Requires the protocol of the next header.
push Encapsulation mode. Adds the MPLS header between the MAC and the network headers.
Requires at least the label option.
mac_push
Encapsulation mode. Adds the MPLS header before the MAC header. Requires at least
the label option.
modify Replace mode. Existing MPLS tag is replaced. label, tc, and ttl are all optional.
dec_ttl
Decrement the TTL field on the outer most MPLS header.
label MPLS_LABEL
Specify the MPLS LABEL for the outer MPLS header. MPLS_LABEL is an unsigned 20bit
integer, the format is detected automatically (e.g. prefix with '0x' for hexadeci-
mal interpretation, etc.).
protocol MPLS_PROTO
Choose the protocol to use. For push actions this must be mpls_uc or mpls_mc
(mpls_uc is the default). For pop actions it should be the protocol of the next
header. This option cannot be used with modify.
tc MPLS_TC
Choose the TC value for the outer MPLS header. Decimal number in range of 0-7. De-
faults to 0.
ttl MPLS_TTL
Choose the TTL value for the outer MPLS header. Number in range of 0-255. A non-
zero default value will be selected if this is not explicitly set.
bos MPLS_BOS
Manually configure the bottom of stack bit for an MPLS header push. The default is
for TC to automatically set (or unset) the bit based on the next header of the
packet.
CONTROL
How to continue after executing this action.
reclassify
Restarts classification by jumping back to the first filter attached to this
action's parent.
pipe Continue with the next action, this is the default.
drop Packet will be dropped without running further actions.
continue
Continue classification with next filter in line.
pass Return to calling qdisc for packet processing. This ends the classification
process.
EXAMPLES
The following example encapsulates incoming IP packets on eth0 into MPLS with a label 123
and sends them out eth1:
#tc qdisc add dev eth0 handle ffff: ingress
#tc filter add dev eth0 protocol ip parent ffff: flower \
action mpls push protocol mpls_uc label 123 \
action mirred egress redirect dev eth1
In this example, incoming MPLS unicast packets on eth0 are decapsulated and redirected to
eth1:
#tc qdisc add dev eth0 handle ffff: ingress
#tc filter add dev eth0 protocol mpls_uc parent ffff: flower \
action mpls pop protocol ipv4 \
action mirred egress redirect dev eth1
Here is another example, where incoming Ethernet frames are encapsulated into MPLS with
label 123 and TTL 64. Then, an outer Ethernet header is added and the resulting frame is
finally sent on eth1:
#tc qdisc add dev eth0 ingress
#tc filter add dev eth0 ingress matchall \
action mpls mac_push label 123 ttl 64 \
action vlan push_eth \
dst_mac 02:00:00:00:00:02 \
src_mac 02:00:00:00:00:01 \
action mirred egress redirect dev eth1
The following example assumes that incoming MPLS packets with label 123 transport Ethernet
frames. The outer Ethernet and the MPLS headers are stripped, then the inner Ethernet
frame is sent on eth1:
#tc qdisc add dev eth0 ingress
#tc filter add dev eth0 ingress protocol mpls_uc \
flower mpls_label 123 mpls_bos 1 \
action vlan pop_eth \
action mpls pop protocol teb \
action mirred egress redirect dev eth1
SEE ALSO
tc(8), tc-mirred(8), tc-vlan(8)
iproute2 22 May 2019 MPLS manipulation action in tc(8)
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