Subject: Re: determine outgoing interface (eth0,eth1) for a packet according to the dest IP

From: Andi Kleen <[email-masked]>
Date: Tue, 25 Apr 2006 16:48:09 +0200

On Tuesday 25 April 2006 16:44, John Que wrote:
> Thanks a lot !
> 
>   I had tried the sending RTM_GETROUTE message using a NETLINK_ROUTE
> 	socket in a User Space program and it went OK.
> 	
> 	It gaves correct routing struct which I could parse.
> 	In fact it gave the rotuing table.
> 	But in sending that message I did not specify a certain
> 	dest IP.
> 	Consider the follwing simple scenario: I have 2 gateways
> 	(one on eth0,one on eth1), and I am sending
> 	a packet to some dest IP ; I want to know according to
> 	that ip on which interface (or gw) it will be out
> 	
> 	But where do I specify that certain dest IP ?

You add RTA_SRC and RTA_DST attributes to the query.

-Andi