This patch adds support for NSH packet header fields to the OVS
control plane and the userspace datapath. Initially we support the
fields of the NSH base header as defined in
https://www.ietf.org/id/draft-ietf-sfc-nsh-13.txt
and the fixed context headers specified for metadata format MD1.
The variable length MD2 format is parsed but the TLV context headers
are not yet available for matching.
The NSH fields are modelled as experimenter fields with the dedicated
experimenter class 0x005ad650 proposed for NSH in ONF. The following
fields are defined:
Co-authored-by: Johnson Li <johnson.li@intel.com> Signed-off-by: Yi Yang <yi.y.yang@intel.com> Signed-off-by: Jan Scheurich <jan.scheurich@ericsson.com> Signed-off-by: Ben Pfaff <blp@ovn.org>