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From: Kevin Cernekee <cernekee@chromium.org>
Date: Mon, 15 Jan 2018 20:32:15 -0800
Message-ID: <CAJzqFtak7Ou1Zb62YX-PifvMa5wehsfuMXQt+DfLUSz1-xopRw@mail.gmail.com>
Subject: Re: [PATCH 4.9 27/75] net: igmp: Use correct source address on IGMPv3 reports
To: Sebastian Gottschall <s.gottschall@dd-wrt.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-kernel@vger.kernel.org, stable <stable@vger.kernel.org>,
        Andrew Lunn <andrew@lunn.ch>,
        "David S. Miller" <davem@davemloft.net>
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Sender: linux-kernel-owner@vger.kernel.org

On Mon, Jan 15, 2018 at 8:26 PM, Sebastian Gottschall
<s.gottschall@dd-wrt.com> wrote:
> havent check the source addresses right now. i basicly discovered that this
> patch breaks the igmp routing and all traffic stops
> this here is from a working system with the reverted patch. if you really
> need that i break it again using the patch you need to wait a little bit
>
> 05:14:22.697962 IP 10.88.195.138 > 239.35.100.8: igmp v2 report 239.35.100.8

The patch should only affect IGMPv3 behavior.  I did not intend to
change IGMPv2 behavior.  If it does, that might be a bug.

Is it possible that the kernel is using a source IP of 0.0.0.0, but
another host does not recognize it because it does not comply with RFC
3376?

Before/after packet traces would be the best way to see if the kernel
change is causing it to violate the standard.