forked from mirror/openwrt
64ad16993d
RFC4541, section 2.1.2 says:
Packets with a destination IP (DIP) address in the 224.0.0.X range
which are not IGMP must be forwarded on all ports.
And section 3 says:
In IPv6, the data forwarding rules are more straight forward because
MLD is mandated for addresses with scope 2 (link-scope) or greater.
The only exception is the address FF02::1 which is the all hosts
link-scope address for which MLD messages are never sent. Packets
with the all hosts link-scope address should be forwarded on all
ports.
However, currently when a listener on FF12::1 or FF12:🔢0:1 for
example joins then not only packets to these addresses but also for
FF02::1 won't be flooded to all ports anymore, too. Which violates
RFC4541.
This happens because A): They all map to the same ethernet multicast
address, that is 33:33:00:00:00:01. And B) the VLAN profile L2
unknown MC flood setting will only apply flooding of 33:33:00:00:00:01
if there is no specific listener registered for it.
So to fix this, avoid registering an MDB entry in the switch for
33:33:00:00:00:01 at all.
The downside of this is that FF12::1, FF12:🔢0:1 etc.
will always be flooded, too. However fixing the handling of 224.0.0.X
and FF02::1 and adhering to RFC4541 must have priority to avoid
undesired packetloss, to avoid breaking IPv4/IPv6.
Tested-on: ZyXEL GS1900-24HP v1
Fixes:
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|---|---|---|
| .. | ||
| imagebuilder | ||
| linux | ||
| llvm-bpf | ||
| sdk | ||
| toolchain | ||
| Config.in | ||
| Makefile | ||