Subject: RE: rfc2553bis comments

From: Richard Draves <[email-masked]>
Date: Wed, 21 Jun 2000 17:34:14 -0700

>    3) When multicast addresses are stored in a sockaddr_in6, 
> how is the
>    scope id field Interpreted?
> 
> => I believe it should be an interface index because it is the way
> it works today (or before scope id introduction if you prefer :-):
> IPV6_MULTICAST_IF & IPV6_JOIN_GROUP deal with interfaces, not with
> interface sets.

I think Francis's position is easier to implement. Dave's *might* be more
useful to applications but it's messy because there isn't a 1-1
correspondence between unicast scopes and multicast scopes.

> Another point en passant, should in this case a bind() with a non-zero
> scope_id do an automatical IPV6_JOIN_GROUP?

I don't follow this - you can't bind() a multicast address.

Rich
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From: Yves Legrandgerard <[email-masked]>
Date: Thu, 22 Jun 2000 11:25:24 +0200 (CEST)

On 22-Jun-00 Francis Dupont wrote:
>  In your previous mail you wrote:
> 
> => I can and in fact I can bind() many sockets to the same multicast address
> with the same port using SO_REUSEPORT... Of course such sockets should be
> used only for incoming traffic (ie don't send a packet with a multicast
> source address :-).
> 

You're right Francis, BSD manual of socket syscall says:

     SO_REUSEPORT allows completely duplicate bindings by multiple processes
     if they all set SO_REUSEPORT before binding the port.  This option per-
     mits multiple instances of a program to each receive UDP/IP multicast or
     broadcast datagrams destined for the bound port.

                        Yves.

----------------------------------
Yves Legrandgérard
E-Mail: [email-masked]
Date: 22-Jun-00
Time: 11:22:46
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From: Francis Dupont <[email-masked]>
Date: Thu, 22 Jun 2000 11:14:56 +0200

Regards

[email-masked]