On 06/26/2018 06:16 PM, Sowmini Varadhan wrote:
On (06/26/18 13:30), Ka-Cheong Poon wrote:
My answer to this is that if a socket is not bound to a link
local address (meaning it is bound to a non-link local address)
and it is used to send to a link local peer, I think it should
fail.
Hmm, I'm not sure I agree. I dont think this is forbidden
by RFC 6724 - yes, such a packet cannot be forwarded, but
if everything is on the same link, and the dest only has
a link-local, you should not need to (create and) bind
another socket to a link-local to talk to this destination..
In this case, RFC 6724 prefers link local address as source.
While using non-link local address (say ULA) is not forbidden,
doing this can easily cause inter-operability issues (does the
app really know that the non-link local source and the link
local destination addresses are really on the same link?). I
think it is prudent to disallow this in RDS unless there is a
very clear and important reason to do so. BTW, if it is really
needed, it can be added in future.
This is consistent with the scope_id check I mentioned in
the previous mail. If the socket is not bound to a link local
address, the bound_scope_id is 0. So if the socket is used to
send to a link local address (which has a non-zero scope_id), the
check will catch it and fail the call. A new conn should not
be created in this case.
--
K. Poon
ka-cheong.p...@oracle.com
