Re: [RTnet-developers] Monitoring Link Beat

[Jorge A. <j-a...@cr...>]

Em Quinta, 23 de Novembro de 2006 16:02, escreveu:
> Jorge Almeida wrote:
> > 
> > Hello Jan,
> > 
> > I'm trying to implement an easy way of monitoring the link beat of one 
board.
> > 
> > What i want is to pass the index of the board, and internaly call the 
> > "do_ioctl" function that should be initialialized in the rtnet_device 
struct 
> > for each device.
> > 
> > My question is, How do i call the do_ioctl function using the file 
descriptor 
> > of one socket that is open passing the number of the if_index (or the 
> > interface name)? And how rtnet knows wath device to call?
> 
> IOCTLs on RTDM sockets come in over the related protocol handler, see
> e.g. this one for packet sockets:
> 
> 
http://www.rts.uni-hannover.de/rtnet/lxr/source/stack/packet/af_packet.c#L240
> 
> From there on you can easily go down the chain.
> 
> As the IOCTLs are per-socket and not per-device, you have to provide the
> information about the address device within the request packet. Do you
> have some Linux data structure you can reuse for it? Something like for
> SIOCGIFINDEX?

Yes, i have the struct ifreq used for the SIOCGIFINDEX ioctl.

I was checking the code and the path is something like this:

1	Start at "rt_packet_ioctl" (af_packet.c) checking for  a new type of ioctl 
"RTIOC_TYPE_MONITORING"

2	send it to a new function in socket.c "rt_socket_monitoring_ioctl"

3	check the device that we are trying to check the link beat

4	send it to the driver (rt_8139too.c) with the do_ioctl pointer.

In this i only have one doubt:
	Where do i return the result?

Maybe the solution:
	Build a new struct in RTnet has support of the monitoring IOCTLS
	(just for now ) something like

struct SDeviceMonit
{
	int nDeviceIndex;
	int nLinkBeat;
}

This way i can identify the device (nDeviceIndex;) and get the result 
(nLinkBeat;).

Any sugestion??!!

Thanks


> 
> Jan
> 
> 

-- 
Jorge Almeida
j-a...@cr...
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