From: "Linus Lüssing" <linus.luessing@c0d3.blue>
To: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: netdev@vger.kernel.org, bridge@lists.linux-foundation.org,
Florian Westphal <fw@strlen.de>,
linux-kernel@vger.kernel.org, coreteam@netfilter.org,
netfilter-devel@vger.kernel.org,
Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>,
"David S . Miller" <davem@davemloft.net>
Subject: Re: [PATCH net] bridge: ebtables: fix reception of frames DNAT-ed to bridge device
Date: Tue, 21 Mar 2017 01:09:47 +0100 [thread overview]
Message-ID: <20170321000947.GA31709@otheros> (raw)
In-Reply-To: <20170319165506.GA15475@otheros>
On Sun, Mar 19, 2017 at 05:55:06PM +0100, Linus Lüssing wrote:
> On Fri, Mar 17, 2017 at 02:10:44PM +0100, Pablo Neira Ayuso wrote:
> > Wait.
> >
> > May this break local multicast listener that are bound to the bridge
> > interface? Assuming the bridge interface got an IP address, and that
> > there is local multicast listener.
> >
> > Missing anything here?
>
> Hm, for multicast packets usually the code path a few lines
> later in br_handle_frame_finish() should be taken instead.
>
> But you might be right for IP multicast packets with a unicast MAC
> destination (due to whatever reason, for instance via DNAT'ing
> again).
>
> Will check that - thanks!
Ok, I tested DNAT'ing an IP multicast packet to the unicast MAC address
of the bridge interface.
Both ping-ing to an IPv4 and IPv6 multicast listener on br0 worked
and was replied to fine, both with or without changing skb->pkt_type
from PACKET_MULTICAST to PACKET_HOST.
("$ ping 224.1.0.123" and "$ ping6 ff02::1:ff40:707c%in0" from a
network namespace, tied into the bridge via veth)
Also, a DNAT'ed PACKET_BROADCAST worked, with or without changing
it to PACKET_HOST.
I also checked via tcpdump that the destination MAC was changed
successfully.
So, so far I wasn't able to find any bugs with the current
patch. But I think I like the idea of leaving the skb->pkt_type
unaltered for PACKET_MULTICAST and PACKET_BROADCAST, seems cleaner.
I'd just add an "if (skb->pkt_type == PACKET_OTHERHOST)" check
then and resend a PATCH v2.
next prev parent reply other threads:[~2017-03-21 0:09 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-15 3:18 [PATCH net] bridge: ebtables: fix reception of frames DNAT-ed to bridge device Linus Lüssing
2017-03-15 10:26 ` Florian Westphal
2017-03-15 10:42 ` Pablo Neira Ayuso
2017-03-15 14:27 ` Linus Lüssing
2017-03-15 18:15 ` Pablo Neira Ayuso
2017-03-15 21:16 ` Linus Lüssing
2017-03-15 22:06 ` Pablo Neira Ayuso
2017-03-17 13:10 ` Pablo Neira Ayuso
2017-03-19 16:55 ` Linus Lüssing
2017-03-21 0:09 ` Linus Lüssing [this message]
2017-03-21 10:11 ` Pablo Neira Ayuso
2017-03-15 10:34 ` Pablo Neira Ayuso
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