MFC 323170

MFC 323170

    if: Add ioctls to get RSS key and hash type/function.

    It will be needed by hn(4) to configure its RSS key and hash
    type/function in the transparent VF mode in order to match VF's
    RSS settings. The description of the transparent VF mode and
    the RSS hash value issue are here:
    https://svnweb.freebsd.org/base?view=revision&revision=322299
    https://svnweb.freebsd.org/base?view=revision&revision=322485

    These are generic enough to promise two independent IOCs instead
    of abusing SIOCGDRVSPEC.

    Setting RSS key and hash type/function is a different story,
    which probably requires more discussion.

    Comment about UDP_{IPV4,IPV6,IPV6_EX} were only in the patch
    in the review request; these hash types are standardized now.

    Reviewed by:    gallatin
    Sponsored by:   Microsoft
    Differential Revision:  https://reviews.freebsd.org/D12174

git-svn-id: svn://svn.freebsd.org/base/stable/10@324462 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f