dhcpcd-discuss

Re: Whether dhcpcd will support for Information-request packet type?

Roy Marples

Wed Sep 30 09:22:25 2015

Hi Puttaswamy

On 30/09/2015 05:55, Puttaswamy, Rajesh wrote:
> Hi Roy,
> 
> Thanks for your quick reply.
> 
> I need to send Information-request options only through DHCPv6
> "Information-request" packet type as shown in the attached
> (DNS_Options_ScreenShot_with_INFOREQ_pkts.png) Screen shot. But, from
> the "dhcpcd", these information-request options were sent as part of
> "DHCPv6 Solicit" packet type as shown in the attached
> (DNS_Options_ScreenShot .png) Screen shot.
> 
> As I understood from your previous reply, dhcpcd specifically does
> not support "DHCPv6 Information-request" packet type to send/query
> information-request options, and these options are provided only as
> part of DHCPv6 Solicit/DHCPv6 Reply packet type. Is it correct?

dhcpcd specifically does support DHCPv6 Information-request.
I have attached two supporting screenshots and the packet capture.

I will try and say it again more clearly.
dhcpcd will *only* start DHCPv6 Information-request when there is no
current DHCPv6 state, no configured address request in the configuration
(so don't request a NA, TA or PD) AND it has received an ICMPv6 Router
Advertisement packet with the Other Configuration bit set.

What dhcpcd does not currently allow is starting dhcpv6 information
request manually. To facilitate this i have committed this patch:
http://roy.marples.name/projects/dhcpcd/vpatch?from=6723e70c5ed9b284&to=085d5dd2bd481b33

Here is the output running the new option:
$ sudo ./dhcpcd -dB6 --noipv6rs --inform6 iwn0
dhcpcd-6.9.3 starting
iwn0: executing `/libexec/dhcpcd-run-hooks' PREINIT
iwn0: executing `/libexec/dhcpcd-run-hooks' CARRIER
DUID 00:01:00:01:1c:da:32:6e:00:21:6b:ad:ab:38
iwn0: IAID 6b:ad:ab:38
iwn0: requesting DHCPv6 information
iwn0: delaying INFORM6 (xid 0x3410c0), next in 0.8 seconds
iwn0: broadcasting INFORM6 (xid 0x3410c0), next in 1.1 seconds
iwn0: REPLY6 received from fe80::618:d6ff:fef0:2cc
iwn0: refresh in 86400 seconds
iwn0: writing lease `/var/db/dhcpcd-iwn0-UberNET.lease6'
iwn0: executing `/libexec/dhcpcd-run-hooks' INFORM6

Hopefully this now meets your needs.
Let me know if I can help more.

Thanks

Roy

Attachment: ra-otherset.png
Description: PNG image

Attachment: dhcpcd-v6inforeq.png
Description: PNG image

Attachment: dhcpcd-v6inforeq.pcapng
Description: Binary data


Follow-Ups:
RE: Whether dhcpcd will support for Information-request packet type?Puttaswamy, Rajesh
References:
Whether dhcpcd will support for Information-request packet type?Puttaswamy, Rajesh
Re: Whether dhcpcd will support for Information-request packet type?Roy Marples
RE: Whether dhcpcd will support for Information-request packet type?Puttaswamy, Rajesh
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