Linux Ethernet Bridging - Apr 2007 - [Bridge] BPDU generation problem - Further clarifications

Hi Stephan,

After further analysis I find myself pretty clear now. With STP turned off
BPDUs are getting generated but not sent on the ports. So there is no 
problem of affecting the topology of the entire network. However..

Since STP is disabled, br->stp_enabled = 0. The br_dev_open() function
always does a br_stp_enable_bridge(). Which does a br_stp_enable_port()
on each of the ports. Which in turn does a br_port_state_selection(). Which 
finds out STP is disabled and does nothing.

Also whenever the hello timer fires it does a br_config_bpdu_generation().
Which does a br_transmit_config() on each of the ports. Which calls the
br_send_config_bpdu() function. This function generates the entire BPDU
frame & gives it to the br_send_bpdu(). Which finds the STP is disabled
&
discards the packets.

Note: The br_config_bpdu_generation() is also called by the
br_stp_enable_bridge().

I think there is a better way of doing all this..

Regards,
Kishore 


>>> "Kishore A K" <kishoreak@myw.ltindia.com> 05/19/04
11:09AM >>>
Hi Stephan,

But is it not a serious bug cause it is going to the affect the topology of the 
entire network on to which the bridge is connected..

Regards,
Kishore


>>> Stephen Hemminger <shemminger@osdl.org> 05/18/04 09:24PM
>>>
On Tue, 18 May 2004 21:18:01 +0530
"Kishore A K" <kishoreak@myw.ltindia.com> wrote:
> Hi Stephen,
> 
> I have been studying the bridge source & analyzing its flow by putting
printks
> at various places. I am using kernel 2.6.6. I found something really
strange
> happening..
> 
> I have setup a bridge with two ports. I havent enabled stp on the bridge.
Which
> I have confirmed by doing a "brctl show" also. However from the
printks I find
> that BPDUs are getting generated & sent on the ports. Isnt this not
supposed to
> happen?
> 
> Regards,
> Kishore
Probably just a stupid bug.