1.. SPDX-License-Identifier: GPL-2.0
2
3========================================
4Bare UDP Tunnelling Module Documentation
5========================================
6
7There are various L3 encapsulation standards using UDP being discussed to
8leverage the UDP based load balancing capability of different networks.
9MPLSoUDP (__ https://tools.ietf.org/html/rfc7510) is one among them.
10
11The Bareudp tunnel module provides a generic L3 encapsulation tunnelling
12support for tunnelling different L3 protocols like MPLS, IP, NSH etc. inside
13a UDP tunnel.
14
15Special Handling
16----------------
17The bareudp device supports special handling for MPLS & IP as they can have
18multiple ethertypes.
19MPLS procotcol can have ethertypes ETH_P_MPLS_UC  (unicast) & ETH_P_MPLS_MC (multicast).
20IP protocol can have ethertypes ETH_P_IP (v4) & ETH_P_IPV6 (v6).
21This special handling can be enabled only for ethertypes ETH_P_IP & ETH_P_MPLS_UC
22with a flag called multiproto mode.
23
24Usage
25------
26
271) Device creation & deletion
28
29    a) ip link add dev bareudp0 type bareudp dstport 6635 ethertype 0x8847.
30
31       This creates a bareudp tunnel device which tunnels L3 traffic with ethertype
32       0x8847 (MPLS traffic). The destination port of the UDP header will be set to
33       6635.The device will listen on UDP port 6635 to receive traffic.
34
35    b) ip link delete bareudp0
36
372) Device creation with multiple proto mode enabled
38
39There are two ways to create a bareudp device for MPLS & IP with multiproto mode
40enabled.
41
42    a) ip link add dev  bareudp0 type bareudp dstport 6635 ethertype 0x8847 multiproto
43
44    b) ip link add dev  bareudp0 type bareudp dstport 6635 ethertype mpls
45
463) Device Usage
47
48The bareudp device could be used along with OVS or flower filter in TC.
49The OVS or TC flower layer must set the tunnel information in SKB dst field before
50sending packet buffer to the bareudp device for transmission. On reception the
51bareudp device extracts and stores the tunnel information in SKB dst field before
52passing the packet buffer to the network stack.
53