odhcp6c RENEW timeout issue leads to OOM/OOPS [Was: Re: QEMU x86/64 ubus issues ... ]

[Hans Dedecker]

Hi,

On Sat, Nov 28, 2020 at 5:04 PM Petr Štetiar <ynezz at true.cz> wrote:
>
> Hans Dedecker <dedeckeh at gmail.com> [2020-11-26 21:19:30]:
>
> Hi,
>
> > Is it possible to have a pcap trace of the DHCPv6 messages on the wan ?
> > I hope to find some time next weekend to investigate the issue further
>
> http://ynezz.true.cz/openwrt/odhcp6c/capture.pcap.gz#
Thank you for the traces; looking into the DHCPv6 packets make the issue clear.
Packet 22 is a DHCPv6 reply packet in response to a renew which in its
turn is triggered by a DHCPv6 reconfigure packet.
The packet contains an IA-PD option but no IA prefix option which is
strange. According to the DHCPv6 RFC renew messages must be kept
sending when T1 has expired for either an IA address or IA prefix when
the server does not reply the IA address or IA prefix which is
happening in this case.
I will do further investigation how we could protect odhpc6c against
such DHCPv6 server behavior

Hans
>
> Cheers,
>
> Petr