kern/179901: [netinet] [patch] Multicast SO_REUSEADDR handled incorrectly

[Bernd Walter]

On Mon, Jun 24, 2013 at 03:59:24AM +0000, linimon at freebsd.org wrote:
> Old Synopsis: [patch] Multicast SO_REUSEADDR handled incorrectly
> New Synopsis: [netinet] [patch] Multicast SO_REUSEADDR handled incorrectly
> 
> Responsible-Changed-From-To: freebsd-bugs->freebsd-net
> Responsible-Changed-By: linimon
> Responsible-Changed-When: Mon Jun 24 03:59:05 UTC 2013
> Responsible-Changed-Why: 
> Over to maintainer(s).
> 
> http://www.freebsd.org/cgi/query-pr.cgi?pr=179901
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I don't know if this is related or a different bug, but the same
mentioned commits are suspicious for us.
We had been running with our own IPv6 software into the same REUSEADDR
problem and changed to REUSEPORT as this is how it is done in mcastread
from mcast-tools port.
Don't know where we originally got the REUSEADDR from, probably a Stevens
book.
So far binding works with this change in our software.
However we only receive packets from network and not packets from
the host itself.
We use multicast to notify multiple processes on multiple machines,
including the machine itself.
To reproduce:
 - use two hosts
 - start mcastread on each of them on an interface with shared LAN
 - send via mcastsend on one host
 - packets are received on the other host, but not with the mcastread
   on the same host

-- 
B.Walter <bernd at bwct.de> http://www.bwct.de
Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.