Date: Mon, 7 Oct 2002 17:10:42 -0700 (PDT) From: Julian Elischer <julian@elischer.org> To: Sam Leffler <sam@errno.com> Cc: freebsd-arch@FreeBSD.ORG, freebsd-net@FreeBSD.ORG Subject: Re: CFR: m_tag patch Message-ID: <Pine.BSF.4.21.0210071709270.36581-100000@InterJet.elischer.org> In-Reply-To: <18d301c26e5e$8b5c7a30$52557f42@errno.com>
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On Mon, 7 Oct 2002, Sam Leffler wrote:
> > On Mon, 7 Oct 2002, Sam Leffler wrote:
> > >
> > > If you allocate tag id's using your 32-bit time scheme then the fixed
> values
> > > above would never be hit since they are all for impossible times and so
> > > there'd be no conflict.
> >
> > Just make them all IDs in a single "Legacy" API
> >
>
> Good idea; I see the way out. Try this:
>
> struct m_tag {
> SLIST_ENTRY(m_tag) m_tag_link; /* List of packet tags */
> u_int16_t m_tag_id; /* Tag ID */
> u_int16_t m_tag_len; /* Length of data */
> u_int32_t m_tag_cookie; /* Module/ABI */
> };
>
> Then define the "Legacy ABI" to be zero (or whatever you want). Then all
> the m_tag_* routines that I specified work only for the Legacy ABI.
> (Whether this is done with shims or whatever doesn't matter.) This gives me
> the compatiblity I want with openbsd and gives you the functionality you
> need for netgraph. For new work we can specify users should avoid the
> Legacy ABI.
>
> Cost is basically 4 bytes per tag and an extra compare when walking the
> tags. Happy?
>
definitly.
Each API authout gets to polute his own namespace as much as he
wants.. :-)
> Sam
>
>
>
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