dhcpcd-discuss

It is the following router from the ISP. I'm not sure what make is behind
it:
http://www.swisscom.ch/de/privatkunden/internet/internet-zuhause/devices/centro-grande-analog-standard.html

Other devices (an Ubuntu laptop, and an Android phone) seem to work fine
with it: they get both an IPv4 and an IPv6, which is visible in the UI of
the router.

This is all pretty standard afaik, so I would be inclined to say that the
router is ok. Would it be worth investigating if it is a potential bug in
dhcpcd? My own knowledge at this level of networking is unfortunately not
that high though, so other than providing more details I can't be of much
help.

The OS of my desktop is Archlinux, which uses systemd, which is the one
that goes crazy from receiving so much logging (constant HD activity).
Currently I'm getting more worried about the actual ipv6 problem than the
logging :)

Regards,

-Lode


On Mon, Jun 2, 2014 at 10:47 AM, Roy Marples <roy@xxxxxxxxxxxx> wrote:

> Hi
>
>
> On 01/06/2014 11:36, Lode wrote:
>
>> Unless I disable noipv6rs, dhcpcd will write the following to the
>> syslog every few seconds:
>>
>> eth0: invalid prefix in RA
>> ipv6nd_handlera: Success
>>
>
> Here is the code which logs this error
>
>                 if (IN6_IS_ADDR_MULTICAST(&pi->nd_opt_pi_prefix) ||
>                     IN6_IS_ADDR_LINKLOCAL(&pi->nd_opt_pi_prefix))
>                 {
>                         syslog(LOG_ERR,
>                             "%s: invalid prefix in RA", ifp->name);
>                         break;
>                 }
>
> As you can see, the prefix you are being asked to add a route for is
> either a multicast or linklocal prefix, both of which are invalid.
> So it's the sending router that is at fault here.
>
>
>  Writing to the log so much (every few seconds) causes a lot of
>> nuisance, including obscuring other log messages and causing constant
>> disk writes so that the disk never rests.
>>
>
> This is true.
> At most I could move the logging from an error condition to a debug
> condition.
>
>  In addition, I did not find a solution to fix "invalid prefix in RA"
>> and what the actual root cause is. Nothing in my system is broken so
>> it might be a non-issue. The best reference on the internet I found is
>> this post, in which they also have no real clue:
>> https://bbs.archlinux.org/viewtopic.php?id=139302 [1]
>>
>>
>> So I have two requests:
>>
>> -Is it possible to avoid writing to the log so often please? If the
>> message is in there once, it would be sufficient.
>>
>
> See above about moving it to a debug condition.
> The problem of "just the once" means I have to start remembering faulty
> routers.
>
>
>  -What is the actual problem of "invalid prefix in RA", and how to fix?
>> Does it not like my router? It seems to be in ipv6nd.c.
>>
>
> No, it doesn't like your router.
> An advertised prefix cannot be a linklocal or multicast one, which your
> router is sadly advertising.
> For reference, can you state the make and model of your router please?
>
> Thanks
>
> Roy
>
>