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Groups > linux.kernel > #1554782
| From | Linus Lüssing <linus.luessing@c0d3.blue> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH net-next] bridge: multicast to unicast |
| Date | 2017-01-10 00:20 +0100 |
| Message-ID | <sXRol-1WC-3@gated-at.bofh.it> (permalink) |
| References | <sXHyF-4eL-9@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Mon, Jan 09, 2017 at 10:42:46PM +0100, Johannes Berg wrote:
> On Mon, 2017-01-09 at 22:33 +0100, Linus Lüssing wrote:
> > On Mon, Jan 09, 2017 at 01:44:03PM +0100, Johannes Berg wrote:
> > >
> > > > > A host SHOULD silently discard a datagram that is
> > > > > received via
> > > > > a link-layer broadcast (see Section 2.4) but does not
> > > > > specify
> > > > > an IP multicast or broadcast destination address.
> > > >
> > > > This example is the other way round. It specifies how the IP
> > > > destination should look like in case of link-layer broadcast. Not
> > > > how the link-layer destination should look like in case of a
> > > > multicast/broadcast IP destination.
> > >
> > > You stopped reading too early - snipped the context part for you :)
> >
> > Sorry for writing to you directly, but I still have some
> > difficulties. In pseudo-code that line says:
> >
> > -----
> > if ll_dst(pkt) == bcast AND ip_dst(pkt) != mcast/bcast:
> > -> drop(pkt)
> > -----
> >
> > But after multicast-to-unicast conversion, we have:
> >
> > -----
> > ll_dst(pkt) == ucast AND ip_dst(pkt) == mcast
> > -----
> >
> > So none of the two requirements for dropping are matched?
> >
>
> Exactly. My point is that this is breaking the expectation that hosts
> are actually able to drop such packets.
[readding CCs I removed earlier]
Ah! Thanks. I was worried about creating packetloss :D.
Hm, for this other other way round, I think it does not apply for
the bridge multicast-to-unicast patch if I'm not misreading the bridge code:
For a packet with a link-layer multicast address but a unicast IP
destination, the bridge MDB lookup will fail.
(http://lxr.free-electrons.com/source/net/bridge/br_multicast.c?v=4.8#L178
returns NULL)
Case A): No multicast router on port:
-> bridge, br_multicast_flood(), will drop the packet already
(no matter if multicast-to-unicast is enabled or not)
Case B): Multicast router present on port:
-> The new patch does not apply multicast-to-unicast but just floods
packet unaltered
("else { port = rport; addr = NULL; }" branch)
Regards, Linus
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Re: [PATCH net-next] bridge: multicast to unicast Johannes Berg <johannes@sipsolutions.net> - 2017-01-06 14:00 +0100
Re: [PATCH net-next] bridge: multicast to unicast Felix Fietkau <nbd@nbd.name> - 2017-01-06 15:00 +0100
Re: [PATCH net-next] bridge: multicast to unicast Johannes Berg <johannes@sipsolutions.net> - 2017-01-06 15:00 +0100
Re: [PATCH net-next] bridge: multicast to unicast Felix Fietkau <nbd@nbd.name> - 2017-01-06 15:40 +0100
Re: [PATCH net-next] bridge: multicast to unicast "M. Braun" <michael-dev@fami-braun.de> - 2017-01-07 11:50 +0100
Re: [PATCH net-next] bridge: multicast to unicast Linus Lüssing <linus.luessing@c0d3.blue> - 2017-01-07 16:00 +0100
Re: [PATCH net-next] bridge: multicast to unicast Johannes Berg <johannes@sipsolutions.net> - 2017-01-09 09:10 +0100
Re: [PATCH net-next] bridge: multicast to unicast "M. Braun" <michael-dev@fami-braun.de> - 2017-01-09 13:00 +0100
Re: [PATCH net-next] bridge: multicast to unicast Johannes Berg <johannes@sipsolutions.net> - 2017-01-09 13:20 +0100
Re: [PATCH net-next] bridge: multicast to unicast michael-dev <michael-dev@fami-braun.de> - 2017-01-09 16:30 +0100
Re: [PATCH net-next] bridge: multicast to unicast Johannes Berg <johannes@sipsolutions.net> - 2017-01-09 16:50 +0100
Re: [PATCH net-next] bridge: multicast to unicast Linus Lüssing <linus.luessing@c0d3.blue> - 2017-01-09 22:30 +0100
Re: [PATCH net-next] bridge: multicast to unicast Stephen Hemminger <stephen@networkplumber.org> - 2017-01-09 22:40 +0100
Re: [PATCH net-next] bridge: multicast to unicast Linus Lüssing <linus.luessing@c0d3.blue> - 2017-01-10 05:20 +0100
Re: [PATCH net-next] bridge: multicast to unicast Johannes Berg <johannes@sipsolutions.net> - 2017-01-10 12:00 +0100
Re: [PATCH net-next] bridge: multicast to unicast Dave Taht <dave.taht@gmail.com> - 2017-01-10 18:20 +0100
Re: [PATCH net-next] bridge: multicast to unicast Felix Fietkau <nbd@nbd.name> - 2017-01-10 18:30 +0100
Re: [PATCH net-next] bridge: multicast to unicast Dave Taht <dave.taht@gmail.com> - 2017-01-10 19:30 +0100
Re: [PATCH net-next] bridge: multicast to unicast Felix Fietkau <nbd@nbd.name> - 2017-01-10 22:30 +0100
Re: [PATCH net-next] bridge: multicast to unicast Felix Fietkau <nbd@nbd.name> - 2017-01-11 12:40 +0100
Re: [PATCH net-next] bridge: multicast to unicast Felix Fietkau <nbd@nbd.name> - 2017-01-11 13:30 +0100
Re: [PATCH net-next] bridge: multicast to unicast Linus Lüssing <linus.luessing@c0d3.blue> - 2017-01-07 16:20 +0100
Re: [PATCH net-next] bridge: multicast to unicast Johannes Berg <johannes@sipsolutions.net> - 2017-01-09 09:10 +0100
Re: [PATCH net-next] bridge: multicast to unicast Linus Lüssing <linus.luessing@c0d3.blue> - 2017-01-09 13:50 +0100
Re: [PATCH net-next] bridge: multicast to unicast Johannes Berg <johannes@sipsolutions.net> - 2017-01-09 13:50 +0100
Re: [PATCH net-next] bridge: multicast to unicast Linus Lüssing <linus.luessing@c0d3.blue> - 2017-01-10 00:20 +0100
Re: [PATCH net-next] bridge: multicast to unicast Johannes Berg <johannes@sipsolutions.net> - 2017-01-11 10:20 +0100
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