1571912c6SMartin Varghese.. SPDX-License-Identifier: GPL-2.0 2571912c6SMartin Varghese 3571912c6SMartin Varghese======================================== 4571912c6SMartin VargheseBare UDP Tunnelling Module Documentation 5571912c6SMartin Varghese======================================== 6571912c6SMartin Varghese 7571912c6SMartin VargheseThere are various L3 encapsulation standards using UDP being discussed to 8571912c6SMartin Vargheseleverage the UDP based load balancing capability of different networks. 9571912c6SMartin VargheseMPLSoUDP (__ https://tools.ietf.org/html/rfc7510) is one among them. 10571912c6SMartin Varghese 111ed06dbcSMartin VargheseThe Bareudp tunnel module provides a generic L3 encapsulation support for 121ed06dbcSMartin Varghesetunnelling different L3 protocols like MPLS, IP, NSH etc. inside a UDP tunnel. 13571912c6SMartin Varghese 144b5f6723SMartin VargheseSpecial Handling 154b5f6723SMartin Varghese---------------- 164b5f6723SMartin VargheseThe bareudp device supports special handling for MPLS & IP as they can have 174b5f6723SMartin Varghesemultiple ethertypes. 184b5f6723SMartin VargheseMPLS procotcol can have ethertypes ETH_P_MPLS_UC (unicast) & ETH_P_MPLS_MC (multicast). 194b5f6723SMartin VargheseIP protocol can have ethertypes ETH_P_IP (v4) & ETH_P_IPV6 (v6). 204b5f6723SMartin VargheseThis special handling can be enabled only for ethertypes ETH_P_IP & ETH_P_MPLS_UC 214b5f6723SMartin Varghesewith a flag called multiproto mode. 224b5f6723SMartin Varghese 23571912c6SMartin VargheseUsage 24571912c6SMartin Varghese------ 25571912c6SMartin Varghese 26571912c6SMartin Varghese1) Device creation & deletion 27571912c6SMartin Varghese 2834b85adaSGuillaume Nault a) ip link add dev bareudp0 type bareudp dstport 6635 ethertype mpls_uc 29571912c6SMartin Varghese 30571912c6SMartin Varghese This creates a bareudp tunnel device which tunnels L3 traffic with ethertype 31571912c6SMartin Varghese 0x8847 (MPLS traffic). The destination port of the UDP header will be set to 32571912c6SMartin Varghese 6635.The device will listen on UDP port 6635 to receive traffic. 33571912c6SMartin Varghese 34571912c6SMartin Varghese b) ip link delete bareudp0 35571912c6SMartin Varghese 3634b85adaSGuillaume Nault2) Device creation with multiproto mode enabled 374b5f6723SMartin Varghese 3834b85adaSGuillaume NaultThe multiproto mode allows bareudp tunnels to handle several protocols of the 3934b85adaSGuillaume Naultsame family. It is currently only available for IP and MPLS. This mode has to 4034b85adaSGuillaume Naultbe enabled explicitly with the "multiproto" flag. 414b5f6723SMartin Varghese 4234b85adaSGuillaume Nault a) ip link add dev bareudp0 type bareudp dstport 6635 ethertype ipv4 multiproto 434b5f6723SMartin Varghese 4434b85adaSGuillaume Nault For an IPv4 tunnel the multiproto mode allows the tunnel to also handle 4534b85adaSGuillaume Nault IPv6. 4634b85adaSGuillaume Nault 4734b85adaSGuillaume Nault b) ip link add dev bareudp0 type bareudp dstport 6635 ethertype mpls_uc multiproto 4834b85adaSGuillaume Nault 4934b85adaSGuillaume Nault For MPLS, the multiproto mode allows the tunnel to handle both unicast 5034b85adaSGuillaume Nault and multicast MPLS packets. 514b5f6723SMartin Varghese 524b5f6723SMartin Varghese3) Device Usage 53571912c6SMartin Varghese 54571912c6SMartin VargheseThe bareudp device could be used along with OVS or flower filter in TC. 55571912c6SMartin VargheseThe OVS or TC flower layer must set the tunnel information in SKB dst field before 56571912c6SMartin Varghesesending packet buffer to the bareudp device for transmission. On reception the 57571912c6SMartin Varghesebareudp device extracts and stores the tunnel information in SKB dst field before 58571912c6SMartin Varghesepassing the packet buffer to the network stack. 59