netdev - Re: [ipv6] valid_lft and active connections

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Date:	Tue, 14 Jun 2011 20:41:50 +0900
From:	YOSHIFUJI Hideaki <yoshfuji@...ux-ipv6.org>
To:	"Stefan (metze) Metzmacher" <metze@...ba.org>
Cc:	netdev@...r.kernel.org, yoshfuji@...ux-ipv6.org
Subject: Re: [ipv6] valid_lft and active connections

Hello.

Stefan (metze) Metzmacher wrote:
> If I use ipv6 addresses with valid_lft != forever, the ipv6 addresses
> are removed from the interface if the valid_lft expires, even if there're
> established connection which use with address.
> 
> Would it be possible keep the address until the last active connection
> is closed? Otherwise the usable of the privacy extensions will make
> very long living tcp connections impossible.
> 

I cannot imagine why you do not hear RAs before the address expires.

And well, I don't think it is a good idea because it is not what
"valid lifetime" means.

We have 3 states:

1) time <= preferred lifetime
2) preferred lifetime < time <= valid lifetime
3) valid lifetime < lifetime

You can make new connection during the period of 1 and you can continue
using that connection during the period of 1 and 2.

Ask network administrator to advertise longer "valid" lifetime, if
needed, and you may want to make net.ipv6.conf.*.max_addresses larger.


> It would be also ok to add a new special value "used" similar to "forever",
> which triggers the modified behavior.

???

--yoshfuji

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