Subject: Re: [PATCH net-next 2/3] rds: Enable RDS IPv6 support

From: Sowmini Varadhan <[email-masked]>
Date: Tue, 26 Jun 2018 06:16:57 -0400

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..

>  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.