RFC: ethernet links should remember routes the same as addresses

["Christopher Friesen" <cfriesen@nortelnetworks.com>]

I just wanted to get some opinions on this for possible inclusion in 2.5.  
Alexey, if you have any comments...

The scenario is as follows:

Suppose I have a fancy routing setup, dynamically configured by different
binaries, scripts, etc, complete with multiple addresses per link, additional
routing rules and tables specified using iproute2, etc.

An ethernet driver hangs.  Could be a software bug, an intermittent hardware
issue, whatever.  It can be fixed up by setting the link down and up.

Currently, if I run "ip link set dev ethX down", all routes associated with that
IP address in the additional routing tables are lost.  This is somewhat
understandable, as the addresses are not actually available anymore.  However,
the addresses are still visible associated with the link.  Then I run "ip link
set dev ethX up".  The route in the main routing table comes back, but none of
the other routes do.  Somehow, all of those additional routes must be re-added.

Wouldn't it be nice if we could keep track of these additional routes?  Then you
could simply 'down' and 'up' the link and everything would be back the way it
was before.

Does this sound like a good idea?  How hard would this be to implement (not
knowing what the current code looks like, I don't know how this would be done)?

Chris Friesen


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