tc-tunnel_key(8) - Man pages

Tunnel metadata manipulation actioTunnelumetadata manipulation action in tc(8)

NAME
tunnel_key - Tunnel metadata manipulation

SYNOPSIS
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 ]

DESCRIPTION
The tunnel_key action combined with a shared IP tunnel device, allows
one 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 automati-
cally 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 AD-
DRESS 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 ).

OPTIONS
unset Unset the tunnel metadata created by the IP tunnel device. This
function is not mandatory and might be used only in some spe-
cific 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 , geneve_opts ,
vxlan_opts and erspan_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)

dst_port
Outer header destination UDP port

geneve_opts
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.

vxlan_opts
Vxlan metadata options. vxlan_opts is specified in the
form GBP, as a 32bit number. Multiple options is not sup-
ported.

erspan_opts
Erspan metadata options. erspan_opts is specified in the
form VERSION:INDEX:DIR:HWID, where VERSION is represented
as a 8bit number, INDEX as an 32bit number, DIR and HWID
as a 8bit number. Multiple options is not supported.
Note INDEX is used when VERSION is 1, and DIR and HWID
are used when VERSION is 2.

tos Outer header TOS

ttl Outer header TTL

[no]csum
Controls outer UDP checksum. When set to csum (which is
default), the outer UDP checksum is calculated and in-
cluded 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 interface.

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.

EXAMPLES
The following example encapsulates incoming ICMP packets on eth0 into a
vxlan tunnel, by setting metadata to VNI 11, source IP 11.11.0.1 and
destination IP 11.11.0.2, and by redirecting the packet with the meta-
data 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 11.11.0.1 \
dst_ip 11.11.0.2 \
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 11.11.0.2 enc_dst_ip 11.11.0.1 enc_key_id 11 action tunnel_key unset action mirred egress redirect dev tunl1