Re: kern/41005: kernel failed to select correct outgoing address for Multicast packets

[David Young <dyoung%pobox.com@localhost>]

On Fri, Mar 13, 2009 at 01:50:00PM +0000, 
Wolfgang.Stukenbrock%nagler-company.com@localhost wrote:
> >Number:         41005
> >Category:       kern
> >Synopsis:       kernel failed to select correct outgoing address for 
> >Multicast packets
> >Confidential:   no
> >Severity:       serious
> >Priority:       high
> >Responsible:    kern-bug-people
> >State:          open
> >Class:          sw-bug
> >Submitter-Id:   net
> >Arrival-Date:   Fri Mar 13 13:50:00 +0000 2009
> >Originator:     Wolfgang Stukenbrock
> >Release:        NetBSD 4.0
> >Organization:
> Dr. Nagler & Company GmbH
>       
> >Environment:
>       
>       
> System: NetBSD s012 4.0 NetBSD 4.0 (NSW-S012) #9: Fri Mar 13 12:31:52 CET 
> 2009 wgstuken@s012:/usr/src/sys/arch/amd64/compile/NSW-S012 amd64
> Architecture: x86_64
> Machine: amd64
> >Description:
>       If alias addresses are defined on an interface, the kernel does not use 
> the
>       information passed to it by IP_MULTICAST_IF option. Instead it always 
> uses
>       the primary address of the interface.
>       This will break e.g. gated on such interfaces.
>       The problem is, that the information passed by IP_MULTICAST_IF is only 
> used
>       to select the interface itself in the call and to pass it back to user 
> level
>       on a call got getoption IP_MULTICAST_IF under some circumstances.
>       But is is ignored when sending packets with .e.g. sendto().

What if you bind(2) the source address that you want?  Aren't the
multicast packets sent with the correct source address, then?

Dave

-- 
David Young             OJC Technologies
dyoung%ojctech.com@localhost      Urbana, IL * (217) 278-3933