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
