Messages in this thread | | | Date | Mon, 21 Oct 2002 09:02:48 -0400 (EDT) | From | jamal <> | Subject | Re: rtnetlink interface state monitoring problems. |
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On Mon, 21 Oct 2002, David Woodhouse wrote:
> I'm playing with userspace applications which want to monitor the status of > IrDA and Bluetooth devices. Rather than polling for the interface state > (this is a handheld device and polling wastes CPU and battery), I want to > use netlink. > > I have two problems: > > 1. I appear to need CAP_NET_ADMIN to bind to the netlink groups which give > me this information. I can poll for it just fine, but need > elevated privs to be notified. Why is this, and is there a workaround? >
Alexey should be able to give you a better comment. If you can get the status via ioctl there should be no reason why you shouldnt get it via netlink. The change maybe a little involved (look at:net/netlink/af_netlink.c::netlink_bind()) since there are some valid reasons to block non-admin from receiving certain messages. I think the LSM people may have been trying to do this, cant remember details.
> 2. Even root doesn't get notification of state changes for Bluetooth > interfaces, because they're not treated as 'normal' network devices > like IrDA devices are. I can see the logic behind that -- by why > is it done differently from IrDA? Is there a way to get notification > of BT interface state changes?
I cant see anything on netlink and irda; i am also not very familiar with either IrDA or Bluetooth. Regardless, you dont need to be a net device to use netlink. Its a messaging system and you can use it both within the kernel as well as kernel<->userspace. If you get stuck writting the interface ping me privately.
cheers, jamal
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