openconfig / kne / 42137618544

48%

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push

github

Committed by web-flow

Commit Message

meshnet: set link MTU from the topology (#803)

* meshnet: add mtu to the Topology link spec

Add an optional mtu field to the Link of the meshnet Topology CRD (Go type and
the CRD schemas). The schema is structural, so without it the API server would
prune the field.

Part of b/577230109.

* meshnet: add LinkMTU and SetLinkMTU helpers

LinkMTU picks the MTU for both ends of a link: the larger of the two ends'
requests, else the LINK_MTU environment variable, else zero (kernel default).
SetLinkMTU sets the MTU of an interface in a pod network namespace.

Part of b/577230109.

* meshnet: set link MTU on veth, gRPC and VXLAN links

meshnetd now applies the MTU from the Topology link spec. Both ends of a link
get the larger of the MTUs their two Link entries request, or LINK_MTU, or the
kernel default when neither is set, so existing topologies are unchanged.

- veth (same node): the pair is created with the MTU on both ends.
- gRPC (cross node): each daemon sets the MTU of its TAP; the daemon asked to
  create the remote end looks the MTU up from its own Topology cache, so the
  wire protocol is unchanged.
- VXLAN: the MTU is applied best effort, since the kernel caps a vxlan device
  at the node interface MTU less the encapsulation overhead.

MTUs are applied when an interface is created, not enforced on every resync,
so meshnetd does not fight a NOS that sets the MTU of its own interfaces.

Part of b/577230109.

* topo: pass interface MTU to meshnet

Copy topo.Interface.mtu into the meshnet Topology link spec for every node,
including Keysight, so meshnet sets the MTU of the link.

Part of b/577230109.

* docs: describe how KNE and meshnet set link MTU

Part of b/577230109.

* topo/node/keysight: gofmt imports

* meshnet: set gRPC TAP MTU before link setup and skip VXLAN MTU on resync

Coverage Stats

1 of 2 new or added lines in 2 files covered. (50.0%)

1 existing line in 1 file now uncovered.

7345 of 15285 relevant lines covered (48.05%)

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