linux-kernel - How to find the correct source address to a destination in a kernel driver?

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Message-Id: <20141017100801.f1c310de.skraw@ithnet.com>
Date:	Fri, 17 Oct 2014 10:08:01 +0200
From:	Stephan von Krawczynski <skraw@...net.com>
To:	linux-kernel@...r.kernel.org
Subject: How to find the correct source address to a destination in a kernel
 driver?

Hello all,

in former kernels with routing cache things were easy. We just used :

        rt = ip_route_output_key(XXX)
        src = rt->rt_src;

Now if there is no routing cache, we tried this:

        rt = ip_route_output_key(XXX)
        src = inet_select_addr(rt->dst.dev, dst, RT_SCOPE_UNIVERSE);

Unfortunately this does not work with interfaces having multiple ip addresses
and the routing in question is not over the first configured ip.
How do I get the correct src for all possible cases?

-- 
Regards,
Stephan
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