IP Multicast (just 'casting, not rcving)
Gene.Smith at sea.siemens.com
Mon Feb 5 23:23:18 UTC 2001
All I had to do was, in my driver attach fn, set the flag IFF_MULTICAST.
Now it sends a multicast! However, this still does not cause the driver to
support receiving a multicast (which I don't need). Seems like there should
be separate flags for saying that the interface can send multicasts (it
seems like all could?) and that the interface can receive them.
> -----Original Message-----
> From: Smith, Gene [mailto:Gene.Smith at sea.siemens.com]
> Sent: Monday, February 05, 2001 3:46 PM
> To: rtems-users at oarcorp.com
> Subject: IP Multicast (just 'casting, not rcving)
> A while back I asked if multicast was supported in rtems. I have since
> realized that I only need to transmit multicast messages, not
> receive them.
> Does anyone know if rtems might support just sending a
> multicast? When I
> try to send a udp packet to a multcast address, eg,
> 126.96.36.199, my current
> udp code fails in send() with "Network Unreachable" and nothing is
> transmitted on the network per tcpdump. Perhaps I need to set a socket
> option to tell it the multicast interface, although Steven
> seems to says you
> don't need to set socket options or join a group to just send
> a multicast.
> Any ideas while I continue reading rtems-bsd code and Stevens?
> > -----Original Message-----
> > From: suvrat gupta [mailto:suvrat at utstar.com]
> > Sent: Tuesday, August 01, 2000 5:16 PM
> > To: Smith, Gene
> > Subject: Re: IP Multicast
> > I looked at it about two months ago. Seemed like most of the
> > IP stack does
> > support it.. The ethernet driver needs to support multicast related
> > ioctls(add/remove address in the H/W filter).this can be done
> > by usingl
> > ether_addmulti() ether_delmulti() functions(you may need to
> > modify them a bit.
> > Try using the latest RTEMS code.
> > hope this helps. In case you do come to know of some working
> > implementation,
> > let me know.
> > -suvrat
> > "Smith, Gene" wrote:
> > > Is IP Multicast actually supported in RTEMS? If so, has it
> > been used by
> > > anyone? All the drivers in "network" directories seem to
> > say FIXME and
> > > ERROR when referring to multicast. I didn't see multicast
> > mentioned in
> > > Networking Suppliment.
> > >
> > > My application might need some form of multicast. However,
> > a simple subnet
> > > broadcast might do.
> > >
> > > -Gene
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