Responses inline.
On Mar 28, 2012, at 8:21 PM, bbs wrote:
> Problem 1:
> when I set the actions of the flow to send the packets to the NOX, as
> actions=[openflow.OFPAT_OUTPUT, [0, openflow.OFPP_CONTROLLER], and the flow
> sent to the NOX had no packet but only the BufferID of the packet, and when I
> used the command of "dpctl dump-flows ****" to see the flows in the
> openflow-switch, the flow's action, which was "output:controller:ALL", was
> all right.
If you want to get the entire packet, you want to use a large value like 65535,
not 0. 0 does exactly what it sounds like it should -- it sends 0 bytes of the
packet to the controller. In some older versions of OpenFlow, 0 had the
special meaning of "send the whole packet", but that is no longer the case.
> Problem 2:
> when I set the actions of the flow to discard some packets, and the NOX
> received some errors from the openflow-switch, the errors are as follows:
> ERR： received OpenFlow error packet from dpid:********, type=2, code=4, 80
> bytes of data.
I think type2/code4 is OFPET_BAD_ACTION/OFPBAC_BAD_OUT_PORT. In other words,
you seem to be sending an output action with a bad port number. How are you
attempting to discard the packet? By sending an output action to OFPP_NONE,
maybe? Don't do that. If you want to drop a packet, just don't set any
actions at all.
> Problem 3:
> when I want to extract the dhcp packet from the packet sent to the NOX, the
> details of what I had done are as follows:
> #1 def packet_in_callback(dpid, inport, reason, len, bufferid, packet)
> #2 if not packet.parsed:
> #3 log.msg('Incomplete packet')
> #4 dhpacket = packet.find('dhcp')
> #5 if dhpacket:
> #6 .............................
> The function only execute to the 5th line, and the wireshark captured the
> flow that included the dhcp packet. How the function could not find the dhcp
> packet?
Can you provide a pcap capture of such a packet?
As a sidenote, if you're developing a Python-only application in NOX, you might
want to take a look at POX. Python support in NOX is being phased out for the
foreseeable future.
-- Murphy
