Technical data

Gateway Routing Daemon (GATED) Configuration Reference
A.16 The Kernel Statement
A.16.8 Kernel Configuration Syntax
The kernel configuration syntax is as follows:
kernel {
options
[ nochange ]
[ noflushatexit ]
;
routes number ;
flash
[ limit number ]
[ type interface | interior | all ]
;
background
[ limit number ]
[ priority flash | higher | lower ]
;
traceoptions trace_options ;
};
In the kernel configuration syntax:
• options specifies kernel options. Valid options are:
nochange , which, on systems supporting the routing socket, ensures that
changes operations will not be performed, only deletes and adds. This
is useful on early versions of the routing socket code where the change
operation was broken.
noflushatexit , which specifies that during normal shutdown processing
GATED deletes all routes from the kernel forwarding table that do not
have a retain indication. The
noflushatexit option prevents route
deletions at shutdown. Instead, routes are changed and added to make
sure that all the routes marked with retain get installed.
This is useful on systems with thousands of routes. Upon startup GATED
will notice which routes are in the kernel forwarding table and not have
add them back.
•
routes specifies the routes number. On some systems kernel memory is at
a premium. With this parameter a limit can be placed on the maximum
number of routes GATED will install in the kernel. Normally GATED
adds/changes/deletes routes in interface/internal/external order, for example,
it queues interface routes first, followed by internal routes, followed by
external routes, and processes the queue from the beginning. If a this
parameter is specified and the limit is hit, GATED does two scans of the list
instead. On the first scan it does deletes, and also deletes all changed routes,
turning the queued changes into adds. It then rescans the list doing adds in
interface/internal/external order until it hits the limit again. This will tend
to favor internal routes over external routes. The default is not to limit the
number of routes in the kernel forwarding table.
•
flash specifies that a route has changed. The process of notifying the
protocols is called a flash update. The kernel forwarding table interface is
the first to be notified. Normally a maximum of 20 interface routes may be
processed during one flash update. The flash command allows tuning of the
following parameters:
limit number , which specifies the maximum number of routes which may
be processed during one flash update. The default is 20. A value of -1
A–28 Gateway Routing Daemon (GATED) Configuration Reference