lkml.org 
[lkml]   [1999]   [Oct]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Network iface is down but pingable
Krzysztof Halasa wrote:

> David Ford <david@kalifornia.com> writes:
>
> > if i load balance several NICs with a daemon, i'd feel pretty silly (stupid
> > really) shelling to run a script to bring routes back up.
>
> You can ask your daemon to add routes for you. I'm not sure if I like the
> idea of automatic routes created by "ifconfig up", but using them you
> already have a route to your peer/network when the interface is up.
> A daemon like mrtd can add default and other routes for you without
> any need for slow scripts.

on some of my machines i have over a dozen non-simplified routes that are built
from a variety of signals. those signals don't necessarily exist again until
some time in the future. in this case, it is silly to continuously save a state
table of the routes so when a NIC swap occurs i have correct information. ip
link set up/down only brings up a route specific to the scope of the interface,
none other.

the concept of having a daemon add routes a split second after routes are deleted
by the kernel is rather silly. just leave the routes there and mark them dead.
it's less work for the kernel and less work for userland.

> > the ONLY affect NIC's status change should have on routing is marking routes
> > dead or alive, NOT flushing them.
> >
> > the current method, pardon the bluntness, is a m$ way of doing it. knock
> > down all the dominoes because one of them needs to go down, now set up the
> > others that should stay up.
>
> Not really. You only flush routes associated with the interface in question,
> not the whole routing table. I'd be very surprised if I someday realize
> that after rmmoding the driver I still have routes using it or even the
> actual interface.

yes really, all the routing depends on interfaces dependant upon those
interfaces. and for the second sentence, routes marked dead are not usable.
routing stops over that route but the state information remains so you only need
mark it active again.


> OTOH ifconfig up/down and rmmod/insmod are rather administrative tasks,
> like adding or removing routes is. Linux doesn't currently have "link/
> protocol down" state, but I think only that condition should mark routes
> as dead without removing them from the table. That would be nice, BTW.

no, ip link set up/down rm/insmod can be human admin tasks and can well be
automated tasks. hmm, i do suggest you delve into the current NET4
functionality. there's a ton more to it than the simplistic "ifconfig" and
"route" i think you're currently familiar with. :)

-d

--
This is Linux Country. On a quiet night, you can hear Windows NT reboot!
Do you remember how to -think- ? Do you remember how to experiment? Linux
__ is an operating system that brings back the fun and adventure in computing.
\/ for linux-kernel: please read linux/Documentation/* before posting problems




-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:54    [W:0.043 / U:0.404 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site