[Dnsmasq-discuss] [PATCH v2] DHCPv6: Honor assigning IPv6 address based on MAC address

[Geert Stappers]

On Sun, May 03, 2020 at 01:23:15PM +0200, Pali Rohár wrote:
> Currently IPv6 addresses are assigned to tuple (IAID, DUID). When system
> changes IAID/DUID then old assigned IPv6 address cannot be reused, even
> when in config file was DHCPv6 assignment based on MAC address (and not on
> DUID).
> 
> IAID/DUID is changed when rebooting from one operating system to another;
> or after reinstalling system. In reality it is normal that DUID of some
> machine is changed, so people rather assign also IPv6 addresses based on
> MAC address.
> 
> So assigning IPv6 based on MAC address in dnsmasq is currently semi-broken.

How to reproduce that  semi-brokenness?

 
> This patch tries to fix it and honors IPv6 config rules with MAC address,
> to always assign particular IPv6 address to specific MAC address (when
> configured). And ignores the fact if IAID/DUID was changed.
> 
> Normally IPv6 address should be assigned by IAID/DUID (which also state
> DHCPv6 RFCs), but dnsmasq has already some support for assigning IPv6
> address based on MAC address, when users configured in config file.
> 
> So this patch just tries to fix above problem for user configuration with
> MAC addresses. It does not change assignment based on DUID.
> ---
> 
> This is my original patch rebased on top of current git master branch.

Acknowledge


> Previous email with this patch probably dropped into spambox
> and was not processed.

 (unspoken words +
  http://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2020q2/014018.html )


> So please let me know if now this email was correctly received.
 
Recieved the patch and was able to  `git am` it.
It did compile and passed the unittests.

No further check was done.  Mostly because not facing the problem that
patch submitter has.  Probably some day I will, hence the above 'How to
reproduce that  semi-brokenness?'


>  src/rfc3315.c | 55 +++++++++++++++++++++++++++++++++++++++++++--------
>  1 file changed, 47 insertions(+), 8 deletions(-)
> 
> diff --git a/src/rfc3315.c b/src/rfc3315.c
> index b3f0a0a..e588b13 100644
> --- a/src/rfc3315.c
> +++ b/src/rfc3315.c
     ... 142 lines of actual patch ...


Groeten
Geert Stappers
-- 
Silence is hard to parse