Starting with the second error...
NameError: global name 'bufid' is not defined
This is because you're using the variable name "bufid", but there's no such
variable. You have this in a packet-in handler because it's one of the
parameters to the event handler. For a stats-in, there's obviously no
associated packet, so there's no bufid parameter, so using bufid doesn't make
sense here.
The first error is...
ERR:received Openflow error packet from dpid=000000000001: type=1, code=8, 128
bytes of data
Looking that up, we see that type 1 code 8 is BAD_REQUEST, BUFFER_UNKNOWN.
We can see why if we look at install_datapath_flow()'s definition versus your
call to it.
install_datapath_flow:
self, # Passed implicitly
dp_id, # You pass "dpid"
attrs, # You pass "flow" (the match dict)
idle_timeout, # You pass CACHE_TIMEOUT
hard_timeout, # You pass DROP_TIMEOUT
actions, # You pass "actions" (which is [])
buffer_id=None, # You pass openflow.OFP_DEFAULT_PRIORITY
priority=openflow.OFP_DEFAULT_PRIORITY, # You pass "inport"
inport=None, # You pass nothing
packet=None # You pass nothing
As you can see, you 're passing openflow.OFP_DEFAULT_PRIORITY as if it were the
buffer ID. No wonder the buffer is unknown! I don't think you need the inport
here anyway, so you probably just want to do something like:
self.install_datapath_flow(dpid, flow, CACHE_TIMEOUT, DROP_TIMEOUT, [])
Also, note that you are always operating on the first flow even if it was some
other flow that went over your threshold (because you are using flows[0] to
pick out the port/match later). You probably want to not just keep track of
the winning byte_count, but also the index of the flow with the winning
byte_count.
temp = 0
temp_index = None
for index, item in enumerate(flows):
val = int(item['byte_count']) # byte_count is probably a bigint... do you
need the int?
if val > temp:
temp = val
temp_index = index
...
flow = flows[temp_index]['match']
Hope that helps.
-- Murphy
On Sep 2, 2011, at 10:21 PM, chris oleke wrote:
>
> Well it does make some sense and should be able to work but when I try it in
> my application like shown below, I get the following errors
>
> def handle_flow_stats_in(self, dpid, flows, more, xid):
>
> print "Flow stats in from datapath", longlong_to_octstr(dpid)[6:]
>
> temp = 0
>
> for item in flows:
>
> val = item['byte_count']
>
> z = int(val)
>
> if z > temp:
>
> temp = z
>
>
> print "highest", temp
>
> if temp > 1000:
>
> inport = flows[0]['match']['in_port']
>
> flow = flows[0]['match']
>
> print inport
>
> #print flow
>
> actions = []
>
> self.install_datapath_flow(dpid, flow, CACHE_TIMEOUT,
> DROP_TIMEOUT,
>
> actions,
> openflow.OFP_DEFAULT_PRIORITY,
>
> inport)
>
>
>
> First error:
>
>
> 00006|openflow-event|ERR:received Openflow error packet from
> dpid=000000000001: type=1, code=8, 128 bytes of data
>
>
>
> When I change the command for installing a flow to contain the bufid and buf:
>
> self.install_datapath_flow(dpid, flow, CACHE_TIMEOUT, DROP_TIMEOUT,
>
> actions, bufid,
> openflow.OFP_DEFAULT_PRIORITY,
>
> inport, buf)
>
> I get this error:
>
>
> 00006|pyrt|ERR:unable to invoke a Python event handler:
>
> Traceback (most recent call last):
>
> File "./nox/lib/util.py", line 192, in f
>
> ret = f.cb(event.datapath_id, event.flows, event.more, event.xid)
>
> File "./nox/netapps/routing/samplerouting.py", line 181, in
> handle_flow_stats_in
>
> actions, bufid, openflow.OFP_DEFAULT_PRIORITY,
>
> NameError: global name 'bufid' is not defined
>
>
>
> Where could the problem be?
>
>
>
> Thanks,
>
> Chris
>
>
>
> On Sat, Sep 3, 2011 at 1:47 AM, Murphy McCauley <jam...@nau.edu> wrote:
> Yes. From the flow stats event, you should be able to do something like:
> e.flows[0]["match"] to get the match dictionary to use with
> install_datapath_flow(), send_flow_command(), etc. for that flow.
>
> -- Murphy
>
> On Sep 2, 2011, at 3:16 PM, chris oleke wrote:
>
> > Hi,
> >
> > I am trying to create a rate-limiting functionality in my application using
> > the flow statistics that I obtain from the switch. I'm using the byte_count
> > from the flows to match against a threshold value that when exceeded will
> > be used to prompt flows to be dropped. Is it possible to create a packet
> > within NOX that I would use to install a flow just like the case in a
> > packet_in_event? In other words I'd like to know if I can use the details
> > obtained from a particular flow statistic to create a packet and
> > consequently have a flow sent to the switch that will be used to drop the
> > packets that match the flow.
> >
> >
> > Thanks,
> > Chris
> > _______________________________________________
> > nox-dev mailing list
> > nox-dev@noxrepo.org
> > http://noxrepo.org/mailman/listinfo/nox-dev
>
>
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