Messages in this thread | | | Date | Mon, 29 Jul 2019 15:14:21 +0200 | From | "Allan W. Nielsen" <> | Subject | Re: [PATCH] net: bridge: Allow bridge to joing multicast groups |
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The 07/29/2019 15:22, Nikolay Aleksandrov wrote: > Yes, all of the multicast code is handled differently, it doesn't go through the fdb > lookup or code at all. I don't see how you'll do a lookup in the fdb table with a > multicast mac address, take a look at br_handle_frame_finish() and you'll notice > that when a multicast dmac is detected then we use the bridge mcast code for lookups > and forwarding.
Here is my thinking (needs much more elaboration, which will come if we do a patch to test it out):
In br_pkt_type
Rename BR_PKT_MULTICAST to BR_PKT_MULTICAST_IP Add a new type called BR_PKT_MULTICAST_L2
In br_handle_frame_finish
if (is_multicast_ether_addr(dest)) { /* by definition the broadcast is also a multicast address */ if (is_broadcast_ether_addr(dest)) { pkt_type = BR_PKT_BROADCAST; local_rcv = true; } else { pkt_type = BR_PKT_MULTICAST; if (br_multicast_rcv(br, p, skb, vid)) goto drop; } }
Change the code above to detect if it is a BR_PKT_MULTICAST_IP or a BR_PKT_MULTICAST_L2
In this section:
switch (pkt_type) { .... }
if (dst) { } else { }
Add awareness to the BR_PKT_MULTICAST_L2 type, and allow it do forwarding according to the static entry if it is there.
> If you're trying to achieve Rx only on the bridge of these then > why not just use Ido's tc suggestion or even the ip maddr add offload for each port ? > > If you add a multicast mac in the fdb (currently allowed, but has no effect) and you > use dev_mc_add() as suggested that'd just be a hack to pass it down and it is already > possible to achieve via other methods, no need to go through the bridge.
Well, I wanted the SW bridge implementation to behave the same with an without HW offload.
And also, I believe that is conceptually belongs to the MAC tables.
/Allan
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