[Dnsmasq-discuss] DHCPv6 - Relay-reply dhcpv6.option.type 79 Client Link-Layer Address with zero length

[Harald Jensas]

On 2/12/23 20:23, Simon Kelley wrote:
> 
> 
> On 12/02/2023 16:19, Harald Jensas wrote:
>> On 2/11/23 23:39, Simon Kelley wrote:
>>> Is dnsmasq acting as the relay or as the DHCP server in that pcap?
>>>
>>> Simon.
>>>
>>
>> dnsmasq is acting as the DHCP server in the attached pcap.
> 
> I'm confused.
> 
> The code in dnsmasq to handle a dhcpv6 packet which has been relayed is 
> at line 233 in src/rfc3315.c
> 
> For each option in the relayed message:
> 
> If it's an encapsulated DHCPv6 request, is gets replaced with an 
> encapsulated DHCPv6 reply.
> 
> Any other option gets copied from the request to the reply EXCEPT option 
> 79, which is not copied at all.
> 
> I can't see where the zero-length option 79 is coming from in that code, 
> it shouldn't be copied at all.
> 
> 
> Looking at git blame, this code was fixed in 2019, around version 2.81. 
> Are you using really old code?
> 

Yes, we are running ancient code. :(
It is 2.79 with several patches/fixes applied, but not commit 
f8c77edbdffb8ada7753ea9fa104f0f6da70cfe3 which is what we need.

Sorry for the noise, you fixed this already long time ago.


--
Harald