Re: [ewg] DHCP over InfiniBand Update

sebastien dugue
2010-09-06T13:03:23Z

Hi Hal,

On Tue, 31 Aug 2010 16:09:19 -0400
Hal Rosenstock <hal.rosenstock-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:

> Hi,
>
> There appear to be two basic approaches to supporting DHCP (over
> InfiniBand) in Linux. There's LPF support (4.1.1 based) and older
> (3.0.4 based) socket support.
>
> The 4.1.1 LPF patches are:
> http://lists.openfabrics.org/pipermail/ewg/2010-May/015265.html
> http://lists.openfabrics.org/pipermail/ewg/2010-May/015266.html
> http://lists.openfabrics.org/pipermail/ewg/2010-May/015264.html
> The last being Matthieu Hautreux's <matthieu.hautreux at cea.fr>
> improved XID generation (same as
> https://lists.isc.org/mailman/htdig/dhcp-hackers/2009-January/001773.html).
>
> AFAIT an LPF based approach will only work on older kernels (due to
> elimination of CONFIG_FILTER support). Is this accurate ?

Where have you seen that the LPF approach does not work on recent kernels?
AFAICR, the CONFIG_FILTER disappeared a long time ago. Unless I'm missing
something, you only need the CONFIG_PACKET option.

Sébastien.

>
> OFED has two patches for 3.0.4 for a socket approach in
> http://www.openfabrics.org/git/?p=~tziporet/docs.git;a=tree;f=dhcp;h=aec68a2905559c8ed91f1157fa11d78cccb266cd;hb=ofed_1_5
> dhcp-3.0.4.patch
> 0001-Make-DHCP-server-print-HW-info.patch
>
> I've been upporting those to a 4.x based DHCP and have a fundamental
> question which occurs even with the 3.0.4 socket based version. On the
> client machine, the DHCPOFFER in response to the DHCPDISCOVER is
> received (seen with tcpdump) but never seems to make it to the
> dhclient application. I can't see any kernel stack error counters
> incremented so I'm mystified as to what could be going wrong. I've
> also tried this on a number of different kernels. Any idea on why this
> might be or how to figure out where that packet is going ? I do see
> the dhcp client port with netstat -a --udp -n
> udp 0 0 0.0.0.0:68 0.0.0.0:*
> udp 0 0 0.0.0.0:68 0.0.0.0:*
> Any idea on what I'm missing ?
>
> Also, is any of this work making it's way into a released DHCP ?
> What's the process for this ? Is there some branch in a source
> repository where this work is available ?
>
> Thanks in advance for any pointers on all this.
>
> -- Hal
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