Geneve (`geneve`)

Layer: L2 (data link)
Header: variable length
Notes: Encapsulation and tunnels

Reached from

Lower layer	Selector	Value
`udp`	`dst_port` / `src_port`	6081 (0x17c1)

Field	Type	Default	Auto	Description
`version`	`uint(2)`	`0`		Geneve version (0).
`opt_len`	`uint(6)`	`0`		Length of the options region, in 4-octet words.
`o_flag`	`uint(1)`	`0`		OAM packet flag.
`c_flag`	`uint(1)`	`0`		Critical options present flag.
`reserved_flags`	`uint(6)`	`0`
`protocol_type`	`enum(16)`	`25944` (transparent_ethernet)	Protocol number of the next layer (see Next layer)	EtherType of the encapsulated payload.
`vni`	`uint(24)`	`0`		24-bit Geneve Virtual Network Identifier.
`reserved`	`uint(8)`	`0`
`options`	`bytes` — `opt_len * 4` octets	`""`		Geneve options (opaque; sized by opt_len).

The next layer is selected by protocol_type; when the field is Auto the builder writes the value of the protocol stacked above.