Subject: Re: Revised a little, was Re: Multicast oddity
To: Greg Troxel <gdt@ir.bbn.com>
From: Bill Studenmund <wrstuden@netbsd.org>
List: tech-net
Date: 04/29/2005 20:30:22
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On Fri, Apr 29, 2005 at 05:39:17PM -0700, Bill Studenmund wrote:
> On Fri, Apr 29, 2005 at 08:09:49PM -0400, Greg Troxel wrote:
>=20
> I'm sending to 10.0.0.6 (which is the address on fxp0, the default nic fo=
r=20
> v4). My socket is bound to 0.0.0.0, and the multicast address is=20
> 239.255.255.253.
>=20
> As I mentioned, I'm getting a statistics increase for each error (I can=
=20
> corelate three errors to three stat incs). The stat is ips_odropped, and=
=20
> the error is EADDRNOTAVAIL. That combination shows up in ip_output() in=
=20
> the place where we check the source address being multicast!
>=20
> How in the world did we go from unbound sending to 10.0.0.6 to having a=
=20
> multicast (239.255.255.253) address as our source!

I'll look at the multicast stuff more, but I think joining is messed up.=20
After the program has started up (but hasn't done anything), netstat -an=20
shows:

udp        0      0  *.427                  *.*                  =20
udp        0      0  239.255.255.253.427    *.*                  =20

No wonder the kernel's confused.

Take care,

Bill

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