On 13/04/2022 11:55, Nikolay Aleksandrov wrote: > On 13/04/2022 11:51, Joachim Wiberg wrote: >> On Tue, Apr 12, 2022 at 20:37, Nikolay Aleksandrov <razor@xxxxxxxxxxxxx> wrote: >>> On 12/04/2022 20:27, Joachim Wiberg wrote: >>>> [snip] >>>> From this I'd like to argue that our current behavior in the bridge is >>>> wrong. To me it's clear that, since we have a confiugration option, we >>>> should forward unknown IP multicast to all MCAST_FLOOD ports (as well as >>>> the router ports). >>> Definitely not wrong. In fact: >>> "Switches that do not forward unregistered packets to all ports must >>> include a configuration option to force the flooding of unregistered >>> packets on specified ports. [..]" >>> is already implemented because the admin can mark any port as a router and >>> enable flooding to it. >> >> Hmm, I understand your point (here and below), and won't drive this >> point further. Instead I'll pick up on what you said in your first >> reply ... (below, last) >> >> Btw, thank you for taking the time to reply and explain your standpoint, >> really helps my understanding of how we can develop the bridge further, >> without breaking userspace! :) >> >>>> [1]: https://www.rfc-editor.org/rfc/rfc4541.html#section-2.1.2 >>> RFC4541 is only recommending, it's not a mandatory behaviour. This >>> default has been placed for a very long time and a lot of users and >>> tests take it into consideration. >> >> Noted. >> >>> We cannot break such assumptions and start suddenly flooding packets, >>> but we can leave it up to the admin or distribution/network software >>> to configure it as default. >> >> So, if I add a bridge flag, default off as you mentioned out earlier, >> which changes the default behavior of MCAST_FLOOD, then you'd be OK with >> that? Something cheeky like this perhaps: >> >> if (!ipv4_is_local_multicast(ip_hdr(skb)->daddr)) >> BR_INPUT_SKB_CB(skb)->mrouters_only = !br_opt_get(br, BROPT_MCAST_FLOOD_RFC4541); > > Exactly! And that is exactly what I had in mind when I wrote it. :) > Just please use a different option name that better suggests what it does. > Thanks, > Nik > >> >> >> Best regards >> /Joachim >
