Re: [PATCH] make ipv4 multicast packets only get delivered to sockets thatare joined to group

[David Stevens]

Jeff Layton <jlayton@xxxxxxxxxxxxxxx> wrote on 09/13/2006 09:12:23 AM:

> Most of the RFC's I've looked at don't seem to have much to say about
> how multicasting works at the socket level. Is there an RFC or
> specification that spells this out, or is this one of those situations
> where things are somewhat open to interpretation?

        RFC's are standards for protocols and are concerned with
interoperability among multiple implementations. They, in general,
do not define API's (and those that do are "informational").
        There are after-the-fact standards for sockets, including
POSIX, but older features are effectively defined by industry
practice; in this case, Deering's BSD implementation from nearly
20 years ago.
        Sections 7.1 & 7.2 of RFC 988 [Deering, 1986] hint at this
interpretation (separation of membership from socket delivery),
esp. when it says "Incoming multicast IP datagrams are
delivered to upper-layer protocol modules using the
same 'Receive IP' operation as normal, unicast
datagrams."
        But Deering's own implementation, which
does not distinguish which socket joined the group,
is the source of the standard practice.

                                                        +-DLS

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/