Hello,

I was just merging my local changes with whats in the git and noticed
this change never made it in.

In ipv4.py self.id = int(time.time()) but this should be self.id =
int(time.time)) &0xffff  (since the field is only 2bytes)

Aaron


On Mon, Aug 8, 2011 at 6:31 PM, Murphy McCauley <jam...@nau.edu> wrote:
> It's the identification field of the IPv4 header.  Mostly this is used to
> match up fragments (which should all retain the same value).  So time.time()
> isn't really a very good value for it anyway, as it should be relatively
> unique, but int(time.time()) is only unique for packets sent in different
> seconds which seems like a fairly unsafe assumption.  We should probably
> just use a counter.  Which, looking at the code... it looks like may have
> been done in the past (ip_id field) and then changed.  It should probably be
> changed back. :)  I think that's what I did when I fixed it before; it must
> just have not made it out of some experimental branch.  Sorry it got you!
>
> -- Murphy
>
> On Aug 8, 2011, at 3:18 PM, Aaron Rosen wrote:
>
> Thanks that did the trick.
>
> Yea I thought this was strange too since this used to work a while ago.
>
> Out of curiosity what is id in ipv4.py I see that it holds the time but why
> is that needed?
>
> Thanks again,
>
> Aaron
>
> On Mon, Aug 8, 2011 at 6:13 PM, Murphy McCauley <jam...@nau.edu> wrote:
>>
>> Strange, I am positive that I have fixed this.  Maybe it just hasn't
>> gotten pushed yet.
>>
>> In ipv4.py around line 76, try something like...
>> self.id = int(time.time()) & 0xffff
>>
>> -- Murphy
>>
>> On Aug 8, 2011, at 3:08 PM, Aaron Rosen wrote:
>>
>> Thanks,
>>
>> I hate to bug you again but this looks fine to me?
>>
>> iplen = 39     len("hello world")(11)  + udp header(8)  + 20 (ip_header)
>> 17 =   UDP_PROTOCOL
>>
>>   bad packet [69, 0, 39, 1312840938, 0, 64, 17, 0, 167837954, 167837953]
>> 00019|pyrt|ERR:unable to invoke a Python event handler:
>> Traceback (most recent call last):
>>   File "./nox/lib/util.py", line 114, in f
>>     event.total_len, buffer_id, packet)
>>   File "./nox/coreapps/examples/sos.py", line 644, in packet_in_callback
>>     learn(dpid, inport, packet, packet.arr, bufid)
>>   File "./nox/coreapps/examples/sos.py", line 212, in learn
>>     forward(dpid, inport, packet, packet.arr, bufid, TRUNK_PORT)
>>   File "./nox/coreapps/examples/sos.py", line 333, in forward
>>     ret = install_agent_flows(dpid, inport, packet, buf, bufid,
>> TRUNK_PORT);
>>   File "./nox/coreapps/examples/sos.py", line 594, in install_agent_flows
>>     inst.send_openflow_packet(dp_near, inform_dest.tostring(),
>> inst.Agents[dp_near]['inport'], inport)
>>   File "./nox/lib/packet/packet_base.py", line 118, in tostring
>>     return ''.join((buf, self.next.tostring()))
>>   File "./nox/lib/packet/packet_base.py", line 113, in tostring
>>     buf = self.hdr()
>>   File "./nox/lib/packet/ipv4.py", line 179, in hdr
>>     self.dstip)
>> error: 'H' format requires 0 <= number <= 65535
>>
>>
>> On Mon, Aug 8, 2011 at 5:32 PM, Murphy McCauley <jam...@nau.edu> wrote:
>>>
>>> I think you just have a field with a bad value.
>>>
>>> Try replacing the checksum function with something like this to help you
>>> spot it:
>>>
>>> def checksum(self):
>>>   try:
>>>     data = struct.pack('!BBHHBBHII', (self.v << 4) + self.hl, self.tos,
>>>                        self.iplen, self.id,
>>>                        (self.flags << 13) | self.frag, self.ttl,
>>>                        self.protocol, 0, self.srcip,
>>>                        self.dstip)
>>>     return checksum(data, 0)
>>>   except:
>>>     print "bad packet",[(self.v << 4) + self.hl,
>>>                         self.tos,
>>>                         self.iplen, self.id,
>>>                         (self.flags << 13) | self.frag, self.ttl,
>>>                         self.protocol, 0, self.srcip,
>>>                         self.dstip]
>>>
>>> -- Murphy
>>>
>>> On Aug 8, 2011, at 1:50 PM, Aaron Rosen wrote:
>>>
>>> Hello,
>>>
>>> I emailed the mailing list about this before but it seems like maybe
>>> something changed or maybe I'm blind. Anyways, the following code generates
>>> the following execption.  Any ideas what's going wrong?
>>>
>>>
>>>  def send_udp(mac, dstip, srcip, port, payload):
>>>     l4 = udp()
>>>     l4.srcport = 1999
>>>     l4.dstport = 1998
>>>     l4.len = udp.MIN_LEN  + len("hello world")
>>>     l4.set_payload("hello world")
>>>     l4.arr = l4.tostring()
>>>
>>>     l3 = ipv4()
>>>     l3.iplen = ipv4.MIN_LEN + l4.len
>>>     l3.protocol = ipv4.UDP_PROTOCOL
>>>     l3.dstip = ipstr_to_int("10.1.1.1")
>>>     l3.srcip = ipstr_to_int("10.1.1.2")
>>>     l3.set_payload(l4)
>>>
>>>     l2 = ethernet()
>>>     l2.set_payload(l3)
>>>     l2.dst = octstr_to_array("00:00:00:00:00:01")
>>>     l2.src = octstr_to_array("00:00:00:00:00:09")
>>>     l2.type = ethernet.IP_TYPE
>>>     l3.checksum()
>>>     l4.csum = l4.checksum()
>>>     return l2
>>>
>>>
>>> 00019|pyrt|ERR:unable to invoke a Python event handler:
>>> Traceback (most recent call last):
>>>   File "./nox/lib/util.py", line 114, in f
>>>     event.total_len, buffer_id, packet)
>>>   File "./nox/coreapps/examples/sos.py", line 626, in packet_in_callback
>>>     learn(dpid, inport, packet, packet.arr, bufid)
>>>   File "./nox/coreapps/examples/sos.py", line 194, in learn
>>>     forward(dpid, inport, packet, packet.arr, bufid, TRUNK_PORT)
>>>   File "./nox/coreapps/examples/sos.py", line 315, in forward
>>>     ret = install_agent_flows(dpid, inport, packet, buf, bufid,
>>> TRUNK_PORT);
>>>   File "./nox/coreapps/examples/sos.py", line 575, in install_agent_flows
>>>     inform_dest = send_udp(mac, dstip, srcip, port, payload)
>>>   File "./nox/coreapps/examples/sos.py", line 89, in send_udp
>>>     l3.checksum()
>>>   File "./nox/lib/packet/ipv4.py", line 162, in checksum
>>>     self.dstip)
>>> error: 'H' format requires 0 <= number <= 65535
>>>
>>>
>>> On Mon, Jun 20, 2011 at 1:59 PM, Aaron Rosen <aro...@clemson.edu> wrote:
>>>>
>>>> Thanks Murphy!
>>>>
>>>> You're right, that did the trick.
>>>>
>>>> Aaron
>>>>
>>>> On Mon, Jun 20, 2011 at 1:55 PM, Murphy McCauley <jam...@nau.edu> wrote:
>>>> > So I think the call to l3.checksum() is extraneous, but the real issue
>>>> > is
>>>> > probably that l3.iplen should be ipv4.MIN_LEN + l4.len.
>>>> >
>>>> > -- Murphy
>>>> >
>>>> > On Monday, June 20, 2011 09:42:07 AM Aaron Rosen wrote:
>>>> >> Hi Murphy,
>>>> >>
>>>> >> wow... Opps...
>>>> >>
>>>> >> I'm trying the following: This doesn't return any errors but in
>>>> >> wireshark the packet_outs say Malformed UDP packets.
>>>> >>
>>>> >> def send_udp_message():
>>>> >>
>>>> >>    l4 = udp()
>>>> >>    l4.srcport = 1999
>>>> >>    l4.dstport = 1888
>>>> >>    l4.len = udp.MIN_LEN + len("hello_world")
>>>> >>    l4.set_payload("Hello_world")
>>>> >>    l4.arr = l4.tostring()
>>>> >>
>>>> >>    l3 = ipv4()
>>>> >>    l3.iplen = ipv4.MIN_LEN
>>>> >>    l3.protocol = ipv4.UDP_PROTOCOL
>>>> >>    l3.dstip = ipstr_to_int("130.127.39.7");
>>>> >>    l3.srcip = ipstr_to_int("1.1.1.1");
>>>> >>    l3.set_payload(l4)
>>>> >>
>>>> >>    l2 = ethernet()
>>>> >>    l2.set_payload(l3)
>>>> >>    l2.dst = octstr_to_array("00:00:00:00:00:02")
>>>> >>    l2.dst = octstr_to_array("a1:00:04:00:0a:04")
>>>> >>    l2.type = ethernet.IP_TYPE
>>>> >>    l3.checksum()
>>>> >>    l4.csum = l4.checksum()
>>>> >>
>>>> >>    return l2
>>>> >>
>>>> >> ....
>>>> >>     inst.send_openflow_packet(dpid, send_udp_message().tostring(),
>>>> >> openflow.OFPP_FLOOD, inport)
>>>> >>     source = mac_to_str(packet.src)
>>>> >>
>>>> >> On Mon, Jun 20, 2011 at 12:29 PM, Murphy McCauley <jam...@nau.edu>
>>>> >> wrote:
>>>> >> > Unfortunately, your tweak breaks the logic of the assert.
>>>> >> >
>>>> >> > The assert is asserting that self.next is a packet_base of some
>>>> >> > sort OR a
>>>> >> > string.  You've set it to a string, so... it should be a string.
>>>> >> >  So it
>>>> >> > should definitely not be a packet_base.  So the first of your
>>>> >> > asserts
>>>> >> > will always fail.
>>>> >> >
>>>> >> > For the sake of testing, would you please comment out the first of
>>>> >> > your
>>>> >> > two asserts (leaving only the one against type('')), and let me
>>>> >> > know the
>>>> >> > result?
>>>> >> >
>>>> >> > -- Murphy
>>>> >> >
>>>> >> > On Monday, June 20, 2011 09:22:23 AM Aaron Rosen wrote:
>>>> >> >> Hi Murphy,
>>>> >> >>
>>>> >> >> I'm using zaku but the one in destiny looked the same to be.
>>>> >> >>
>>>> >> >> I changed to assert to be on two lines so I could see which one
>>>> >> >> was
>>>> >> >> firing.
>>>> >> >>
>>>> >> >>     def checksum(self):
>>>> >> >>         #assert(isinstance(self.next, packet_base) or
>>>> >> >> type(self.next)
>>>> >> >> == type(''))
>>>> >> >>         assert(isinstance(self.next, packet_base))
>>>> >> >>         assert(type(self.next) == type(''))
>>>> >> >>
>>>> >> >>
>>>> >> >> Thanks,
>>>> >> >>
>>>> >> >> Aaron
>>>> >> >>
>>>> >> >> On Mon, Jun 20, 2011 at 12:19 PM, Murphy McCauley <jam...@nau.edu>
>>>> >> >> wrote:
>>>> >> >> > What NOX are you using?  Your udp.py does not seem to be the one
>>>> >> >> > in
>>>> >> >> > zaku or destiny...
>>>> >> >> >
>>>> >> >> > -- Murphy
>>>> >> >> >
>>>> >> >> > On Sunday, June 19, 2011 03:34:20 PM Aaron Rosen wrote:
>>>> >> >> >> Hello,
>>>> >> >> >>
>>>> >> >> >> I'm trying to send udp packets from my controller but I'm
>>>> >> >> >> getting the
>>>> >> >> >> following assertion when I call udp().checksum(). I was hoping
>>>> >> >> >> someone could point out where I'm going wrong.
>>>> >> >> >>
>>>> >> >> >> Thanks,
>>>> >> >> >>
>>>> >> >> >> Aaron
>>>> >> >> >>
>>>> >> >> >> Traceback (most recent call last):
>>>> >> >> >>   File "./nox/lib/util.py", line 116, in f
>>>> >> >> >>     event.total_len, buffer_id, packet)
>>>> >> >> >>   File "./nox/coreapps/examples/sos.py", line 299, in
>>>> >> >> >> packet_in_callback learn(dpid, inport, packet)
>>>> >> >> >>   File "./nox/coreapps/examples/sos.py", line 56, in learn
>>>> >> >> >>     send_packet = send_udp_message()
>>>> >> >> >>   File "./nox/coreapps/examples/sos.py", line 48, in
>>>> >> >> >> send_udp_message
>>>> >> >> >>     l4.csum = l4.checksum()
>>>> >> >> >>   File "./nox/lib/packet/udp.py", line 111, in checksum
>>>> >> >> >>     assert(isinstance(self.next, packet_base))
>>>> >> >> >> AssertionError
>>>> >> >> >>
>>>> >> >> >>
>>>> >> >> >> def send_udp_message():
>>>> >> >> >>
>>>> >> >> >>     l4 = udp()
>>>> >> >> >>     l4.srcport = 1999
>>>> >> >> >>     l4.dstport = 1888
>>>> >> >> >>     l4.len = udp.MIN_LEN + len("hello_world")
>>>> >> >> >>     l4.set_payload("Hello_world")
>>>> >> >> >>
>>>> >> >> >>     l3 = ipv4()
>>>> >> >> >>     l3.iplen = ipv4.MIN_LEN
>>>> >> >> >>     l3.protocol = ipv4.UDP_PROTOCOL
>>>> >> >> >>     l3.dstip = ipstr_to_int("130.127.39.7");
>>>> >> >> >>     l3.srcip = ipstr_to_int("1.1.1.1");
>>>> >> >> >>     l3.set_payload(l4)
>>>> >> >> >>
>>>> >> >> >>     l2 = ethernet()
>>>> >> >> >>     l2.set_payload(l3)
>>>> >> >> >>     l2.dst = octstr_to_array("00:00:00:00:00:02")
>>>> >> >> >>     l2.dst = octstr_to_array("a1:00:04:00:0a:04")
>>>> >> >> >>     l2.type = ethernet.IP_TYPE
>>>> >> >> >>     l3.checksum()
>>>> >> >> >>     l4.csum = l4.checksum()
>>>> >> >> >>
>>>> >> >> >>     return l2
>>>> >> >> >>
>>>> >> >> >>
>>>> >> >> >> ....
>>>> >> >> >>     send_packet = send_udp_message()
>>>> >> >> >>     inst.send_openflow_packet(dpid, send_packet.tostring(),
>>>> >> >> >> openflow.OFPP_FLOOD, inport)
>>>> >
>>>>
>>>>
>>>>
>>>> --
>>>> 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
>>
>>
>>
>
>
>
> --
> Aaron O. Rosen
> Masters Student - Network Communication
> 306B Fluor Daniel
>
>
>



-- 
Aaron O. Rosen
Masters Student - Network Communication
306B Fluor Daniel
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