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Re: RedBoot: gateway support


Grant Edwards wrote:

> Yesterday I added default gateway support to RedBoot --
> including using DHCP to get the netmask. It appears to be
> working, but I've got more testing I want to do.
>
> Here's the current situation:
>
> The routing logic (including determining Ethernet addresses)
> occurs at the UDP/TCP layer:
>
>  * UDP uses the netmask/gatway configuration and then ARP
>
>  * TCP uses whatever Ethernet address the SYN packet came from.
>
> The IP code then uses whatever Ethernet address is passed from
> the higher layers.
>
> This should work for a vast majority of networks.  The only
> problem would be a network where outgoing TCP/IP packets are
> supposed to go to a _different_ gateway than the one they came
> in on.  I've never seen a network like that, but it's doable.
>
> If one wants proper gateway support for TCP packets as well,
> there are two options:
>
>  1) Copy routing logic that's in UDP to TCP.
>     [It's only about 5 lines of code, so it's no big deal.]
>
>  2) Put the routing logic in the IP layer and have the UDP and
>     TCP layer pass just the IP address to the IP layer rather
>     than passing IP+Ethernet to the IP layer.  [This is a
>     little more work, but feels like "the right thing to do".]
>
> Questions:
>
>  1) Is anybody interested in having gateway support put into
>     RedBoot?
>

Yes.  If you send it to me, we can see about making this "main stream".
Note: I'll probably need a copyright assignment from you if we don't
already have it.

>
>  2) If yes, is the current scheme (TCP uses source Ethernet,
>     UDP does gateway and ARP) good enough?
>
>  3) If not, should gateway/Ethernet address logic be moved into
>     the IP layer, or should the routing logic be duplicated in
>     UDP and TCP code?
>

Ideally, the choices between these should be a configuration option
(eCos == Embedded Configurable Operating System)!!  Once I see the
details, I'll let you know.


>
> --
> Grant Edwards
> grante@visi.com


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