Multipath routing - failover version

[M.S. Motanu]

I've ported the multipath routing patch by Ed Tanzer
<tanzer at dsm.fordham.edu
<https://mail.stsnet.ro/squirrelmail/src/compose.php?send_to=tanzer%40dsm.fordham.edu>>
for FreeBSD 4.8-STABLE to FreeBSD 6.1-RELEASE.

The patch modifies the kernel and the userland programs netstat and route
so that for the same destination it is possible to specify two or more
different gateways (paths).

Switching between different paths is done by the kernel based on the link
state of the interface associated with the gateway. This way when can
achieve a level of redundancy at the link level (this is not a routing
protocol!).

The original patch did not have failover in mind, it addressed the problem
of load balancing. But the same results can be achieved with this patch
with minor changes to the code.

The patch files and installation instructions can be downloaded
from:http://miauris.freehostia.com/mpath/mpath.tar.gz

Comments are welcomed!