[Dnsmasq-discuss] Environment variable DNSMASQ_CLIENT_ID

[Community Member]

Follow up from "RaspberryPi PCAP file" thread.

On Sat, Dec 4, 2021 at 1:42 PM Geert Stappers wrote:
> On Sat, Dec 04, 2021 at 12:11:13PM -0800, Carl Karsten wrote:
> > On Sat, Dec 4, 2021 at 10:12 AM Geert Stappers wrote:
> > >
> > > My observation on the PCAP file
> > > * there are several stages
> > > * each stage starts with a (partial) DHCP session
> > >
> > >
> > > The first stage:
> > > * DHCP Discover with option 97, Client Identifier,
> > >   f6 27 6d 7a f6 27 6d 7a f6 27 6d 7a f6 27 6d 7a
> > >   from client
> > > * DHCP Offer with filename 'ipxe/undionly.kpxe'
> > >   from server
  .....
> > > The second stage:
> > > * DHCP Discover with option 97, Client Identifier,
> > >   f6 27 6d 7a f6 27 6d 7a f6 27 6d 7a f6 27 6d 7a
> > >   from client  (yes, that is the same identifier)
> > > * DHCP Offer with filename 'ipxe/undionly.kpxe'
> > >   from server (yes, that is the same filename)
  .....
> >
> > My pi netboot needs are basically satisfied,
>
> OK
>
> And what about the dnsmasq needs that did get us here???
>

Hmm.. I'm not out of the weeds just yet.

> > > The first stage:
> > > * DHCP Discover with option 97, Client Identifier,
> > >   f6 27 6d 7a f6 27 6d 7a f6 27 6d 7a f6 27 6d 7a

I need access to that value.  That's the serial number  f6 27 6d 7a
repeated 4 times.
but not
DNSMASQ_CLIENT_ID=01:b8:27:eb:6d:27:f6

Here is a quick test I did:
dhcp-script=/root/dnsmasq-test1.sh

$ cat /root/dnsmasq-test1.sh
#!/bin/bash -x
echo $* >> /tmp/dnsmasq-test1.txt
/usr/bin/env  >> /tmp/dnsmasq-test1.txt

$ /tmp/dnsmasq-test1.txt
old b8:27:eb:6d:27:f6 10.21.0.162 raspberrypi
DNSMASQ_TAGS=eth-local
DNSMASQ_INTERFACE=eth-local
DNSMASQ_VENDOR_CLASS=dhcpcd-8.1.2:Linux-5.10.63-v8+:aarch64:BCM2835
LANGUAGE=en_US:en
DNSMASQ_TIME_REMAINING=21600
DNSMASQ_CLIENT_ID=01:b8:27:eb:6d:27:f6
PIDFILE=/run/dnsmasq/dnsmasq.pid
DNSMASQ_LEASE_EXPIRES=1638680174
PWD=/
LANG=en_US.UTF-8
INVOCATION_ID=3bcf8de10dbb44e6b6d844ab5fa06d17
DNSMASQ_REQUESTED_OPTIONS=1,121,33,3,6,12,15,26,28,51,54,58,59,119
SHLVL=1
DNSMASQ_DOMAIN=video.debconf.org
JOURNAL_STREAM=8:28400
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
DNSMASQ_SUPPLIED_HOSTNAME=raspberrypi
_=/usr/bin/env


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