Hello,
I have a problem in the communication between an OpenFlow switch (I use
OpenVswitch) and my NOX controller, connected out-of-band.
The two machines connects, but, after I install the first flow, I get
the following error message:
*openflow-event|ERR:received Openflow error packet from dpid=XXXXXX:
type=1, code=7, 24 bytes of data*
and the "*ovs-openflowd*" terminal showed following error
*"attempt to reuse the buffer"*
While discussing on ovs-discuss mailing list they suggest that "Send a
given buffer_id only in a single OpenFlow request".
I have also seen that there was a guy who wrote here an email as he had
the same problem, so maybe you already solved this.
In my controller I want to install flows after a miss in the flow table.
Here is a part of the code.
def packet_in_callback(self, dp_id, inport, ofp_reason,
total_frame_len, buffer_id, packet):
ethr_pkt = packet.find('ethernet')
if (ofp_reason == openflow.OFPR_NO_MATCH) :
print "!!!!!!!!!!!!!!!!!!! W A R N I N G
!!!!!!!!!!!!!!!!!!!!"
print "No matching rule in the flow table."
if(ethr_pkt.type == ethernet.ARP_TYPE):
m_arp = ethr_pkt.find('arp')
src_ip = ip_to_str(m_arp.protosrc)
dst_ip = ip_to_str(m_arp.protodst)
print "Received an ARP packet with", "\n
src_ip: ", src_ip, "dst_ip: ", dst_ip
arp_type = m_arp.opcode
if (arp_type == 1):
print "This is an ARP REQUEST coming from
port", inport
elif (arp_type == 2):
print "This is an ARP REPLY coming from
port", inport
attr = {}
attr [core.IN_PORT] = inport
attr [core.DL_TYPE] = ethr_pkt.type
idle_timeout = openflow.OFP_FLOW_PERMANENT
hard_timeout = openflow.OFP_FLOW_PERMANENT
priority = 5
if inport == 25:
outport = 26
elif inport == 26:
outport = 25
actions = [[openflow.OFPAT_OUTPUT, [0,outport]]]
self.install_datapath_flow(dp_id,
attr,
idle_timeout,
hard_timeout,
actions,
priority)
elif(ethr_pkt.type == 0x0800):
ip_pkt = packet.find('ipv4')
src_ip = ip_to_str(ip_pkt.srcip)
dst_ip = ip_to_str(ip_pkt.dstip)
tos = ip_pkt.tos
nw_proto = ip_pkt.protocol
print "The incoming packet has the following
structure: ", "\n L3 Protocol: ", nw_proto, "\n src_ip: ", src_ip
print " dst_ip: ", dst_ip, "\n TOS: ", tos
if (ip_pkt.protocol == 1):
attrs = {}
attrs[core.IN_PORT] = inport
attrs[core.DL_TYPE] = ethr_pkt.type
attrs[core.NW_SRC] = ip_pkt.srcip
attrs[core.NW_DST] = ip_pkt.dstip
attrs[core.NW_PROTO] = nw_proto
attrs[core.NW_TOS] = tos
idle_timeout = openflow.OFP_FLOW_PERMANENT
hard_timeout = openflow.OFP_FLOW_PERMANENT
if inport == 26:
outport = 25
elif inport == 25:
outport = 26
actions = [[openflow.OFPAT_OUTPUT, [0,
outport]]]
self.install_datapath_flow(dp_id,
attrs,
idle_timeout,
hard_timeout,
actions,
None,
openflow.OFP_DEFAULT_PRIORITY,
inport,
None)
and so on with other if-else conditions.
Do you have any ideas of what could be the cause of such a behaviour and
how could I solve it?
I also extended NOX source code a little in order to add a new L4
protocol for my work. Do you think this issue could be related to some
mistakes I could have done?
Thanks,
Giorgio Mazza
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