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Message-ID: <542C63FE.9080807@emagii.com>
Date: Wed, 01 Oct 2014 22:28:46 +0200
From: Ulf Samuelsson <netdev@...gii.com>
To: Linux Netdev List <netdev@...r.kernel.org>
Subject: netlink NETLINK_ROUTE failure & Can the kernel really handle IPv6
properly
Trying to write a kernel module handing NETLINK_ROUTE messages for a
3.4.x kernel.
After building the module, it fails to load on my PowerPC P2020 target.
Reason is that the "netlink_kernel_create" fails.
---------------------------------------
struct *sock nls;
...
static int __init my_init (...)
{
...
nls = netlink_kernel_create( &init_net, NETLINK_ROUTE, 0, my_rcv,
NULL, THIS_MODULE);
if (!nls) {
return -ENOMEM;
}
...
}
----------------------------------------
netlick_kernel_create returns 0, so the kernel module fails.
Is there anything wrong wth the call to netlink_kernel_create ?
Goggling show that some code uses "__net_init".
Not sure what that means.
Other code uses a mutex, instead of NULL.
Does NETLINK_ROUTE require a mutex?
All ideas are welcome-
==============
BTW, the problem I am trying to solve is how to connect to an I/F with
an IPv6 link-local address.
An existing kernel module waits for a NETDEV_UP event, and then tries to
communicate
with the link-local address.
This will fail, because (according to a colleague) the I/F enters a
"tentative" state,
where it is trying to decide if it is unique or not.
It will remain in that state for 1-2 seconds, and only afterwards is the
link-local address
available for normal use.
The guys writing the module, claim that the kernel is using NETDEV_UP.
There is very little code in the kernel using NETLINK_ROUTE, even in
latest stable.
It is using NETDEV_UP.
If my colleague is right, the kernel really cannot handle IPv6
link-local addresses properly.
--
Best Regards
Ulf Samuelsson
--
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