Just a note that the packet library in POX is a considerable improvement over
the one in NOX. If you're writing code in Python, you might consider using POX
instead.
-- Murphy
On Apr 26, 2012, at 10:01 AM, Weiyang Mo wrote:
> Hi, Aaron,
>
> I tried my code on real network today. From wireshark, I see that the new
> packets are sent to all hosts. However they are multicast which all hosts
> receive these IP packets.
>
> But I set eth_packet.dst = packet.dst (ff:ff:ff:ff:ff:ff:ff) ,
> eth_packet.src = packet.src
> I think that means that the new packet shouldn't find the destination since
> it is ff:ff:... Then why my hosts can get the new packets?
>
> If I want to manually set the MAC address(For instance, 00:00:00:00:00:02),
> what should I do with eth_packet.dst
>
> eth_packet.dst = mac_to_int("00:00:00:00:00:02") makes an error.
>
> Thanks very much.
>
> Weiyang
>
> 2012/4/25 Aaron Rosen <[email protected]>
> Can you make the following change to ipv4.py and see if this fixes it?
>
>
> ~line 76
> - self.id = int(time.time())
> + self.id = int(time.time()) & 0xffff
>
>
> On Wed, Apr 25, 2012 at 9:40 PM, Weiyang Mo <[email protected]> wrote:
> > I am sorry it still doesn't work. I checked the code and I think the
> > problems happen in the first few lines where I set IP packet attributes.
> >
> > Here is the complete error message: (It seems there's a problem in
> > ipv4_packet.csum = ipv4_packet.checksum(), even I delete this line, same
> > errors)
> >
> > Traceback (most recent call last):
> > File "./nox/lib/util.py", line 114, in f
> > event.total_len, buffer_id, packet)
> > File "./nox/coreapps/examples/sendIPV4.py", line 89, in packet_in_callback
> > self.learn_and_forward(dpid, inport, packet, packet.arr, bufid)
> > File "./nox/coreapps/examples/sendIPV4.py", line 53, in learn_and_forward
> > ipv4_packet.csum = ipv4_packet.checksum()
> > File "./nox/lib/packet/ipv4.py", line 162, in checksum
> > self.dstip)
> > error: 'H' format requires 0 <= number <= 65535
> > Thanks
> >
> > Weiyang
> > 2012/4/25 Aaron Rosen <[email protected]>
> >>
> >> I believe if you do ipstr_to_int("10.0.0.3") it should work.
> >>
> >> Aaron
> >>
> >>
> >> On Wed, Apr 25, 2012 at 6:37 PM, Weiyang Mo <[email protected]>
> >> wrote:
> >> > Hi,
> >> >
> >> > I tested the code and view the packets in Wireshark. For ETH packets,
> >> > it
> >> > works. For IPV4, some errors when I complie it.
> >> >
> >> > (1) I tried ETH packets and the host can receive the packets.
> >> > eth_packet= ethernet()
> >> > eth_packet.set_payload(str("hello"))
> >> > eth_packet.dst = packet.dst
> >> > eth_packet.src = packet.src
> >> > eth_packet.type = ethenet.IP_TYPE
> >> >
> >> > self.send_openflow_packet(dpid,eth_packet.tostring(),inport)
> >> >
> >> > (2) I tried IPV4 and this time an error " "H" format requires
> >> > <=number<=65535 " , here's the following code
> >> >
> >> > ipv4_packet = ipv4()
> >> > payload = str("hello")
> >> > ipv4_packet.iplen = ipv4.MIN_LEN + len(payload)
> >> > ipv4_packet.set_payload(payload)
> >> > ipv4_packet.dstip = str("10.0.0.3")
> >> > ipv4_packet.srcip = str("192.168.56.102")
> >> >
> >> > eth_packet= ethernet()
> >> > eth_packet.set_payload(ipv4_packet)
> >> > packet.dst = packet.dst
> >> > eth_packet.src = packet.src
> >> > eth_packet.type = ethenet.IP_TYPE
> >> > ipv4_packet.csum = ipv4_packet.checksum()
> >> >
> >> > self.send_openflow_packet(dpid,ipv4_packet.tostring(),inport)
> >> >
> >> > I guess why it is failed maybe due to such line ipv4_packet.dstip
> >> > = str("10.0.0.3") is not acceptable. Or other reasons?
> >> >
> >> > Thanks very much.
> >> >
> >> > Weiyang
> >> >
> >> >
> >> >
> >> >
> >> > 2012/4/25 Aaron Rosen <[email protected]>
> >> >>
> >> >> Hi Weiyang,
> >> >>
> >> >> You can inject packets from the controller into the switch like this.
> >> >> Here is some code that I've used to send UDP packets from the
> >> >> controller to hosts.
> >> >>
> >> >> Aaron
> >> >>
> >> >> def send_udp(mac, dstip, srcip, port, payload):
> >> >> l4 = udp()
> >> >> l4.srcport = port
> >> >> l4.dstport = AGENT_MESSAGE_PORT
> >> >> l4.len = udp.MIN_LEN + len(payload)
> >> >> l4.set_payload(payload)
> >> >> l4.arr = l4.tostring()
> >> >> l3 = ipv4()
> >> >> l3.iplen = ipv4.MIN_LEN + l4.len
> >> >> l3.protocol = ipv4.UDP_PROTOCOL
> >> >> l3.dstip = dstip
> >> >> l3.srcip = srcip
> >> >> l3.set_payload(l4)
> >> >> l2 = ethernet()
> >> >> l2.set_payload(l3)
> >> >> l2.dst = mac
> >> >> l2.src = octstr_to_array(CONTROLLER_MAC)
> >> >> l2.type = ethernet.IP_TYPE
> >> >> l4.csum = l4.checksum()
> >> >> return l2
> >> >>
> >> >>
> >> >> inform_dest = send_udp(mac, dstip, srcip, port, payload)
> >> >> inst.send_openflow_packet(HA, inform_dest.tostring(),
> >> >> inst.Agent[HA]['inport'], openflow.OFPP_NONE)
> >> >>
> >> >>
> >> >> On Wed, Apr 25, 2012 at 3:02 PM, Weiyang Mo <[email protected]>
> >> >> wrote:
> >> >> > Thanks very much for your quick reply.
> >> >> >
> >> >> > But I am still confused. do you mean that "the controller instruct a
> >> >> > switch
> >> >> > to send a packet" is not an OpenFlow feature? Or I misunderstand what
> >> >> > you
> >> >> > mean.
> >> >> >
> >> >> > I am sending packets from a client to a server through multiple
> >> >> > OpenFlow
> >> >> > switches. I already have this functionality that the controller
> >> >> > inserts
> >> >> > flow-entries and then the packets can be sent to the server.
> >> >> >
> >> >> > Now, I want to have another action that " when the controller
> >> >> > receives
> >> >> > the
> >> >> > first packet-in message, it can instruct a switch to send a packet
> >> >> > which
> >> >> > contains some data(e.g, hello). And this new packet can be sent to
> >> >> > another
> >> >> > host. If so, the host can run other applications automatically upon
> >> >> > receving
> >> >> > the packet "hello".
> >> >> >
> >> >> > Is it possible?( Packet in->controller controller-> instrucrt
> >> >> > the
> >> >> > switch to create a new packet new packet(Hello) ->host). How
> >> >> > should
> >> >> > I
> >> >> > write the pseudo code.
> >> >> >
> >> >> > Thanks
> >> >> >
> >> >> > Weiyang
> >> >> >
> >> >> > 2012/4/25 Murphy McCauley <[email protected]>
> >> >> >>
> >> >> >> There are no examples of this because this is not an OpenFlow
> >> >> >> feature
> >> >> >> --
> >> >> >> only the controller can instruct a switch to send a packet.
> >> >> >>
> >> >> >> Unless maybe there is some vendor extension for some switches…
> >> >> >>
> >> >> >> -- Murphy
> >> >> >>
> >> >> >> On Apr 25, 2012, at 11:28 AM, Weiyang Mo wrote:
> >> >> >>
> >> >> >> BTW,any example code for this? For instance, the controller wishes
> >> >> >> to
> >> >> >> send
> >> >> >> a packet which contains the data "Hello" through the switch to the
> >> >> >> Output.
> >> >> >>
> >> >> >> How should I write the code? Is it like
> >> >> >> "actions=[openflow.ofp_packet_out,
> >> >> >> ...]" ?
> >> >> >>
> >> >> >> I am not clear because I don't find sample codes. Could anyone
> >> >> >> provides a
> >> >> >> simple sample code?
> >> >> >>
> >> >> >> Regards
> >> >> >>
> >> >> >> Weiyang
> >> >> >> ---------- Forwarded message ----------
> >> >> >> From: Weiyang Mo <[email protected]>
> >> >> >> Date: 2012/4/25
> >> >> >> Subject: instruct the swtich to create a new packet.
> >> >> >> To: [email protected]
> >> >> >>
> >> >> >>
> >> >> >> Hi,all,
> >> >> >>
> >> >> >> I want to insert an action in to flow entry. The action can tell the
> >> >> >> switch to create a new arbitary packet. What command should I use?
> >> >> >>
> >> >> >> Thanks a lot
> >> >> >>
> >> >> >> Weiyang
> >> >> >>
> >> >> >>
> >> >> >
> >> >>
> >> >>
> >> >>
> >> >> --
> >> >> Aaron O. Rosen
> >> >> Masters Student - Network Communication
> >> >> 306B Fluor Daniel
> >> >
> >> >
> >>
> >>
> >>
> >> --
> >> Aaron O. Rosen
> >> Masters Student - Network Communication
> >> 306B Fluor Daniel
> >
> >
>
>
>
> --
> Aaron O. Rosen
> Masters Student - Network Communication
> 306B Fluor Daniel
>
