dhcpcd-discuss

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