[Babel-users] Source-sensitive packet's format

[Dave Taht]

On Tue, Jul 1, 2014 at 11:20 AM, Juliusz Chroboczek
<jch at pps.univ-paris-diderot.fr> wrote:
>> switching to a new TLV number for the newer flag-less format and sending
>> warnings for receipt of the old ("old style babels packet received,
>> please update babel on that machine") seems most comforting to me.
>
> I feel your pain, Dave, but that's something that I have to take a firm
> stand about, or else we'll never get anything done.  Until a TLV is frozen,
> it's not frozen.
>
>> (I'm allergic to the number 13, anyway)
>
> That's when Babel gets its Barmitzvah.
>
>> I would not mind a shim of some sort protecting against older babels's
>> format and newer...
>
> The packet parser is fairly robust, so you'll see some routes missing, but
> assuming enough route diversity Babel should route around the damage.  And
> it will encourage you to do something about all the obsolete versions of
> babeld you're running[1].

I've been shipping babels for 6+ months now, and don't have control
over where they went.

> We could in principle keep the Flags field and simply rename it to Reserved.
> That's one octet lost per source-specific update, until the end of eternity.
> Opinions?

By all means shoot the flags field in the head. My suggestion to use a
new TLV number for it seemed to do the least damage (I am concerned
about mis-parsing stuff), and you can still reuse that number by 2017
in the off chance you add that many tlvs by then.

Don't bother to parse the old tlv, just emit a warning. Still have to
upgrade but  the signs of breakage are clean, as opposed to flaky.

>
> -- Juliusz
>
> [1] I'm picturing an area of Californian shrubland, yellow grass between
>     the dried up bushes, lizards, scorpions, vultures, the odd triceratops
>     here and there.  In the background, a rusting 1985 Cadillac, on bricks.
>     Dave, rubbing his chin and staring thoughtfully at the 2600, is
>     wondering why it won't take his latest OpenWRT image.  Fade out as
>     a black helicopter hovers on the horizon.

/me chortles

I'd prefer it be a rusting Ford XB Falcon , but...


-- 
Dave Täht

NSFW: https://w2.eff.org/Censorship/Internet_censorship_bills/russell_0296_indecent.article