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Date:   Sat, 16 Nov 2019 13:03:12 -0800 (PST)
Message-Id: <20191116.130312.1715585977428653229.davem@davemloft.net>
To:     mcroce@redhat.com
Cc:     netdev@vger.kernel.org, j.vosburgh@gmail.com, vfalico@gmail.com,
        andy@greyhouse.net, linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next] bonding: symmetric ICMP transmit
From:   David Miller <davem@davemloft.net>
In-Reply-To: <20191115111037.7843-1-mcroce@redhat.com>
References: <20191115111037.7843-1-mcroce@redhat.com>
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From: Matteo Croce <mcroce@redhat.com>
Date: Fri, 15 Nov 2019 12:10:37 +0100

> A bonding with layer2+3 or layer3+4 hashing uses the IP addresses and the ports
> to balance packets between slaves. With some network errors, we receive an ICMP
> error packet by the remote host or a router. If sent by a router, the source IP
> can differ from the remote host one. Additionally the ICMP protocol has no port
> numbers, so a layer3+4 bonding will get a different hash than the previous one.
> These two conditions could let the packet go through a different interface than
> the other packets of the same flow:
 ...
> An ICMP error packet contains the header of the packet which caused the network
> error, so inspect it and match the flow against it, so we can send the ICMP via
> the same interface of the previous packet in the flow.
> Move the IP and port dissect code into a generic function bond_flow_ip() and if
> we are dissecting an ICMP error packet, call it again with the adjusted offset.
 ...
> Signed-off-by: Matteo Croce <mcroce@redhat.com>

Applied, thanks.