On Tue, 7 Mar 2006, vishakha s wrote:
Date: Tue, 7 Mar 2006 14:23:14 +0530
From: vishakha s <[EMAIL PROTECTED]>
To: 'Peder Chr. Norgaard' <[EMAIL PROTECTED]>
Cc: "Net-Snmp-Users (E-mail)" <net-snmp-users@lists.sourceforge.net>
Subject: RE: linkup linkdown monitoring impacts the performance
Hi
I read this mail and tried to run with the notification.c you mentioned .It
is generating the trap .But how to use netlink for this .We have to write
some code for opening the socket and what you mean by subscribe to link
change messages.I am not much familiar with this topic .Can you please put
some more light on this exactly how to implement this netlink concept in
net-snmp.
I can only repeat what I already wrote to Robert Story last week: Grab
the "quagga" package from the net and study it:
--------
The "quagga" package uses netlink much the way I suggest (actually I
looked more in the "quagga" code than in the documentation when I wrote my
own piece). Look in the file zebra/rt_netlink.c. The function
netlink_link_change is the place where you recognize the ifUp/ifDown
events - but of course you also need the surrounding infrastructure - the
opening and configuration of the socket, the ordering of this specific
brand of events, the adding of the FD for the socket to the central select
loop etc etc.
I did not find netlink easy to work with - the documentation is sloppy and
complex, and the design is not impressive. It took me something like two
full weeks, with a lot of cheating = looking in kernel source, to get the
hang of it - but when you know how to work it, it works like a charm.
And for performance it really beats using /proc for almost everything.
--------
--
Peder Chr. Nørgaard Senior System Developer, M. Sc.
Ericsson Denmark A/S, Telebit Division
Skanderborgvej 232 tel: +45 30 91 84 31
DK-8260 Viby J, Denmark fax: +45 89 38 51 01
e-mail: [EMAIL PROTECTED]
(old e-mail 2000-2003: [EMAIL PROTECTED])
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