On 2005-08-01, Oliver Jowett <oliver@opencloud.com> wrote:
> There's no dependency on socket PF mentioned there, and the obvious
> reading of that text is that a "level identifier" uniquely identifies
> the "protocol controlling the option" -- so IPPROTO_TCP unambiguously
> means "the TCP protocol".
You're reading more into the spec than is present. It should be obvious
that the existence of, number of and organization of any layers that might
happen to exist below the socket layer is entirely dependent on the
protocol family. The fact that PF-dependent constants are used for
referring to such layers should reinforce this.
> Having multiple socket-PF-dependent namespaces which might overlap is
> just asking for hard-to-find bugs (if you accidentally manage to use the
> wrong namespace for the socket, you run the risk of getting weird
> behaviour rather than an error).
Think about what happens when you add a brand-new protocol family.
--
Andrew, Supernews
http://www.supernews.com - individual and corporate NNTP services