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linux/Documentation/networking/bareudp.rst

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net: UDP tunnel encapsulation module for tunnelling different protocols like MPLS, IP, NSH etc. The Bareudp tunnel module provides a generic L3 encapsulation tunnelling module for tunnelling different protocols like MPLS, IP,NSH etc inside a UDP tunnel. Signed-off-by: Martin Varghese <martin.varghese@nokia.com> Acked-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-02-24 13:27:50 +08:00
.. SPDX-License-Identifier: GPL-2.0
========================================
Bare UDP Tunnelling Module Documentation
========================================
There are various L3 encapsulation standards using UDP being discussed to
leverage the UDP based load balancing capability of different networks.
MPLSoUDP (__ https://tools.ietf.org/html/rfc7510) is one among them.
The Bareudp tunnel module provides a generic L3 encapsulation tunnelling
support for tunnelling different L3 protocols like MPLS, IP, NSH etc. inside
a UDP tunnel.
net: Special handling for IP & MPLS. Special handling is needed in bareudp module for IP & MPLS as they support more than one ethertypes. MPLS has 2 ethertypes. 0x8847 for MPLS unicast and 0x8848 for MPLS multicast. While decapsulating MPLS packet from UDP packet the tunnel destination IP address is checked to determine the ethertype. The ethertype of the packet will be set to 0x8848 if the tunnel destination IP address is a multicast IP address. The ethertype of the packet will be set to 0x8847 if the tunnel destination IP address is a unicast IP address. IP has 2 ethertypes.0x0800 for IPV4 and 0x86dd for IPv6. The version field of the IP header tunnelled will be checked to determine the ethertype. This special handling to tunnel additional ethertypes will be disabled by default and can be enabled using a flag called multiproto. This flag can be used only with ethertypes 0x8847 and 0x0800. Signed-off-by: Martin Varghese <martin.varghese@nokia.com> Acked-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-02-24 13:28:35 +08:00
Special Handling
----------------
The bareudp device supports special handling for MPLS & IP as they can have
multiple ethertypes.
MPLS procotcol can have ethertypes ETH_P_MPLS_UC (unicast) & ETH_P_MPLS_MC (multicast).
IP protocol can have ethertypes ETH_P_IP (v4) & ETH_P_IPV6 (v6).
This special handling can be enabled only for ethertypes ETH_P_IP & ETH_P_MPLS_UC
with a flag called multiproto mode.
net: UDP tunnel encapsulation module for tunnelling different protocols like MPLS, IP, NSH etc. The Bareudp tunnel module provides a generic L3 encapsulation tunnelling module for tunnelling different protocols like MPLS, IP,NSH etc inside a UDP tunnel. Signed-off-by: Martin Varghese <martin.varghese@nokia.com> Acked-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-02-24 13:27:50 +08:00
Usage
------
1) Device creation & deletion
a) ip link add dev bareudp0 type bareudp dstport 6635 ethertype 0x8847.
This creates a bareudp tunnel device which tunnels L3 traffic with ethertype
0x8847 (MPLS traffic). The destination port of the UDP header will be set to
6635.The device will listen on UDP port 6635 to receive traffic.
b) ip link delete bareudp0
net: Special handling for IP & MPLS. Special handling is needed in bareudp module for IP & MPLS as they support more than one ethertypes. MPLS has 2 ethertypes. 0x8847 for MPLS unicast and 0x8848 for MPLS multicast. While decapsulating MPLS packet from UDP packet the tunnel destination IP address is checked to determine the ethertype. The ethertype of the packet will be set to 0x8848 if the tunnel destination IP address is a multicast IP address. The ethertype of the packet will be set to 0x8847 if the tunnel destination IP address is a unicast IP address. IP has 2 ethertypes.0x0800 for IPV4 and 0x86dd for IPv6. The version field of the IP header tunnelled will be checked to determine the ethertype. This special handling to tunnel additional ethertypes will be disabled by default and can be enabled using a flag called multiproto. This flag can be used only with ethertypes 0x8847 and 0x0800. Signed-off-by: Martin Varghese <martin.varghese@nokia.com> Acked-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-02-24 13:28:35 +08:00
2) Device creation with multiple proto mode enabled
There are two ways to create a bareudp device for MPLS & IP with multiproto mode
enabled.
a) ip link add dev bareudp0 type bareudp dstport 6635 ethertype 0x8847 multiproto
b) ip link add dev bareudp0 type bareudp dstport 6635 ethertype mpls
3) Device Usage
net: UDP tunnel encapsulation module for tunnelling different protocols like MPLS, IP, NSH etc. The Bareudp tunnel module provides a generic L3 encapsulation tunnelling module for tunnelling different protocols like MPLS, IP,NSH etc inside a UDP tunnel. Signed-off-by: Martin Varghese <martin.varghese@nokia.com> Acked-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-02-24 13:27:50 +08:00
The bareudp device could be used along with OVS or flower filter in TC.
The OVS or TC flower layer must set the tunnel information in SKB dst field before
sending packet buffer to the bareudp device for transmission. On reception the
bareudp device extracts and stores the tunnel information in SKB dst field before
passing the packet buffer to the network stack.