[lwip-users] driver clarifications for ipv6: loopback, multicast

[chrysn]

hi,

as of fixing my enc28j60 driver[1] to work well with ipv6 as well, i've
stumbled over some corners where there might be a better solution i
haven't found.

* when operating in half duplex mode, ipv6 address autoconfiguration
  failed because i had missed to configure the network card to suppress
  loopback of sent packages; as a result, the returning nd6 packages
  were interpreted as another device's attempt to use the same one.

  is it a general requirement of lwip netif drivers to suppress sent
  packages? or should the nd6 have checked for whether the package comes
  from an own netif?

* i've enabled unconditional reception of multicasts for now. i could
  leave it off by default and fully implement igmp_mac_filter and
  mld_mac_filter, but i could still not know if i missed any other
  potential indications of protocol's willingness to receive multicast.

  is there any interface i cen implement to be informed of the general
  need to receive multicasts?

best regards
chrysn

[1] 
https://gitlab.com/enc28j60driver/enc28j60driver/commit/f60093dd58eabaaaa92c0c87b172d1e5310e08f7

-- 
To use raw power is to make yourself infinitely vulnerable to greater powers.
  -- Bene Gesserit axiom

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