Re: RTA_PRIORITY / RTA_METRICS documentation ?

On 07/07/2017, Jason Vas Dias <[email protected]> wrote:
> Good day -
> If anyone could please point me to some documentation on what
> RTA_PRIORITY and RTA_METRICS route attributes actually do in
> the modern Linux kernel, precisely, I'd be much obliged .
> I understand RTA_METRICS is meant to represent
> 'administrative distance' , and higher values are greater distance and
> therefore
> have lower precedence ?  But what about RTA_PRIORITY ?
> Is numerically  lesser RTA_PRIORITY higher precedence or lower ?
> Does it override or is it overridden by RTA_METRICS?  I can't seem to
> find this documented anywhere - I'll have to dig it out of the kernel
> source code .
> I agree with the rtnetlink(7) manual page where it states 'Fill these
> values in!' below the scant documentation of the RTA_* attributes .
> Is there any attempt to do so out there online or on the cards?
> Thanks & Regards,
> Jason
>

Kind of answering my own question here - RTA_METRICS is an array
of RTAX_* rtattrs - but what do they all mean ? Where are they documented ?
So RTA_PRIORITY is actually the administrative distance / "metric"  and
numerically increasing values confer decreasing precedence on the route?
How do RTAX_* interact with RTA_PRIORITY ?
Reading rtnetlink.h / man rtnetlink(7) is not much use in answering these
questions.