If you mean the field eth_packet.dst yes, I've set it as 00:00:00:00:00:01 the mac address of the host h1.
2013/7/22 Murphy McCauley <[email protected]> > Are you setting the ethernet destination address correctly? > > On Jul 21, 2013, at 3:23 PM, Silvia Fichera wrote: > > Dear Murphy, > I am still experiencing problems to send packets from controller to host. > I tried to send UDP packet via packet_out and they are correctly sent and > received from the host (I can see using tcpdump from receiving host) but if > I try to open a socket with python to read the data, I receive nothing in > the socket even if tcpdump keeps seeing the packets. > > Then I tried to communicate from host to host (opening two xterm from > mininet). If I use netcat listening for data communication is perfect. If I > try to receive data with python sockets I receive the following tcpdump > output (python or netcat send, tcpdump and python listen): > > IP 10.0.0.2.12345 > 10.0.0.1.12345: UDP, length 14 > IP 10.0.0.1 > 10.0.0.2: ICMP 10.0.0.1 udp port 12345 unreachable, length > 50 > > I can see the process listening to the port by lsof -i :12345 > If I put netcat listening to the port, the packet arrives correctly. > I also tried to change the ports but same result. > > Is it maybe a problem of the low-level python socket binding? I am using > simply > s= socket.socket(socket.AF_INET, soket.SOCK_DGRAM) > s.bind((host,port)) > data, addr = sock.recv(10) > > Eventually, I tried in both my ubuntu+mininet installation and in the > virtual machine of mininet (mininet 2.0 with ubuntu 12.10 64 bit) without > success. > > Thanks for support > > regards > > > > > 2013/7/21 Murphy McCauley <[email protected]> > >> If you have any switches, then you'll have received a ConnectionUp event >> when they connect. You can save a reference to the Connection object into >> your own variable at this point. Lots of the example components do this >> (e.g., l2_learning more or less does it). >> >> You can also get the connections later from the OpenFlow nexus, e.g., >> using the core.openflow.connections collection which holds a Connection for >> each connected switch (you can either enumerate it, or you can get >> connections by their DPID). There's also the related >> core.openflow.sendToDPID(dpid, data) method if you know the DPID you want >> to send to. >> >> -- Murphy >> >> On Jul 20, 2013, at 3:57 PM, Silvia Fichera wrote: >> >> Thanks for the summary. >> I was planning to use the packet_out but I am missing the connection >> object (I saw this is usually taken from an event). Can I create a >> connection object (to link controller and a switch) starting the >> communication from the controller? >> >> >> 2013/7/20 Murphy McCauley <[email protected]> >> >>> Let me try restating. >>> >>> Imagine you have a hardware switch. It has some ports which connect it >>> to other switches and hosts and stuff -- it makes a network (call this the >>> "data network" for lack of a better term). >>> >>> So if it's an OpenFlow switch, where is the controller in this picture? >>> >>> One type configuration, the controller can be anywhere on the data >>> network. It communicates with the switch over IP, so why not? You have >>> OpenFlow mixed with normal traffic all over your network. (This is often >>> called "in band control") >>> >>> In another type of configuration (out of band control), you set aside >>> one port on each switch as "special", and use this port to connect to the >>> controller. The special port is *not* a part of the data network. You >>> might say it's part of a control or management network. No normal >>> forwarding ever takes place over this port -- *only* OpenFlow. >>> >>> >>> If your setup looks like the first configuration, a controller can >>> easily send arbitrary traffic over the data network using plain old socket >>> programming. But if your configuration is similar to the second option, >>> there's no direct way for the controller to send to or receive from the >>> data network. The only way it can do it is over OpenFlow -- by instructing >>> one of the switches to send data (via a packet out) and having the switch >>> send data to the controller (via packet in). >>> >>> Of course, even in the second configuration, you could run a cable >>> between a second interface on the controller and a normal port on the >>> switch. That way you have two cables between switch and controller -- one >>> on the management network and one on the data network. >>> >>> >>> Hope that helps. >>> >>> -- Murphy >>> >>> On Jul 20, 2013, at 8:49 AM, Silvia Fichera wrote: >>> >>> > In which case, there's no way to send except via a datapath or a >>> host which actually is. >>> Can you clarify this sentence? >>> >>> Am I following the right way to send packets from the controller to >>> hosts through switches, so using my network, or do I miss something? >>> >>> >>> 2013/7/20 Murphy McCauley <[email protected]> >>> >>>> If I'm understanding correctly, the problem is that the controller >>>> isn't necessarily *on* the data network. In Mininet, for example, it is >>>> often the case that the controller and the datapaths are linked essentially >>>> by a separate management network, and this is not an unusual case in the >>>> real world either. In which case, there's no way to send except via a >>>> datapath or a host which actually is. >>>> >>>> Hope that helps. >>>> >>>> -- Murphy >>>> >>>> On Jul 19, 2013, at 3:39 PM, Silvia Fichera wrote: >>>> >>>> Hello, >>>> I am having trouble sending packets from l3_learning controller to host. >>>> I would like to send UDP packets but if I try to use normal socket from >>>> controller I see no traffic (I minotired it with wireshark on all switches) >>>> unless I send to itself (127.0.0.1). I was also trying to make a switch >>>> sending the controller generated packet in this way: >>>> >>>> http://lists.noxrepo.org/pipermail/pox-dev-noxrepo.org/2012-October/000281.html >>>> >>>> Although I have no traffic too. >>>> I guess the problem is that I am missing something like >>>> >>>> self.connection.send(msg) >>>> >>>> but I don't have any datapath connection with any switch since I want >>>> to start the communication from the controller. >>>> Is there an easier way to send these udp packets? >>>> >>>> thanks >>>> >>>> -- >>>> Silvia Fichera >>>> >>>> >>>> >>> >>> >>> -- >>> Silvia Fichera >>> >>> >>> >> >> >> -- >> Silvia Fichera >> >> >> > > > -- > Silvia Fichera > > > -- Silvia Fichera
