Switching packets from netif_rx()

Switching packets from netif_rx()

[Madhavi]

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Hi

I am implementing a soft switch that can switch packets received on an
interface over certain outgoing interfaces.

The setup is -

	+-----------+		+------------+		+------+
	| Streamer  |-----------|   Switch   |----------| Host |
	+-----------+		+------------+		+------+

The switching functionality is implemented in function netif_rx(). Based
on the list of outgoing interfaces, I am doing the following things.

* Cloning the packets.
* Obtaining outgoing device from outgoing interface index.
* Calling dev_queue_xmit() to send the packet on outgoing device.


I am having the following is PROBLEM with this:
			     ~~~~~~~
When streamer sends a continuous flow of packets to switch, the switch is
able to send upto 3500 (approx. - this varies each time) to the host and
afterwards, the switch is hanging.

I tried sending bunches of 100 packets each with 1 second time gap between
bunches, the switch is functioning without interruptions.

- Is there any problem in the way I am implementing the switch? The
  "bridge" code seems to be doing the same things.
- Or, is there is some limit on the incoming flow rate the kernel will be
  able to handle?

I would be very grateful if someone can help me with this.

Regards
Madhavi.

Madhavi Suram
Software Engineer
Customer Delivery / Networks
Sasken Communication Technologies Limited
139/25, Ring Road, Domlur
Bangalore - 560071 India
Email: madhavis@sasken.com
Tel: + 91 80 5355501 Extn: 8062
Fax: + 91 80 5351133
URL: www.sasken.com


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Re: Switching packets from netif_rx()

[Jeff Garzik]

Madhavi wrote:
> The setup is -
> 
> 	+-----------+		+------------+		+------+
> 	| Streamer  |-----------|   Switch   |----------| Host |
> 	+-----------+		+------------+		+------+
> 
> The switching functionality is implemented in function netif_rx(). Based
> on the list of outgoing interfaces, I am doing the following things.
> 
> * Cloning the packets.
> * Obtaining outgoing device from outgoing interface index.
> * Calling dev_queue_xmit() to send the packet on outgoing device.


As a tangent, this is pretty much what CONFIG_NET_FASTROUTE does...

	Jeff