TypeError: ord() expected string of length 1, but int found Error in Pox Controller

[0xabdi]

1. I ran pox using this command: /pox.py log.level openflow.of_01 forwarding.topo_proactive openflow.discovery
2. Started mininet using a custom python script: sudo python3 proactive_p1.py

Up to this point, everything works fine until I ran this from the mininet prompt: h1 dhclient h1-eth0

The mininet prompt hangs for minutes and the following appears on the pox prompt:

INFO:core:POX 0.7.0 (gar) is up.
INFO:openflow.of_01:[00-00-00-00-00-01 2] connected
ERROR:core:Exception while handling OpenFlowNexus!PacketIn...
Traceback (most recent call last):
  File "/home/abdirahman/pox/pox/lib/revent/revent.py", line 242, in raiseEventNoErrors
    return self.raiseEvent(event, *args, **kw)
  File "/home/abdirahman/pox/pox/lib/revent/revent.py", line 295, in raiseEvent
    rv = event._invoke(handler, *args, **kw)
  File "/home/abdirahman/pox/pox/lib/revent/revent.py", line 168, in _invoke
    return handler(self, *args, **kw)
  File "/home/abdirahman/pox/pox/openflow/discovery.py", line 347, in _handle_openflow_PacketIn
    packet = event.parsed
  File "/home/abdirahman/pox/pox/openflow/__init__.py", line 193, in parsed
    return self.parse()
  File "/home/abdirahman/pox/pox/openflow/__init__.py", line 185, in parse
    self._parsed = ethernet(self.data)
  File "/home/abdirahman/pox/pox/lib/packet/ethernet.py", line 106, in __init__
    self.parse(raw)
  File "/home/abdirahman/pox/pox/lib/packet/ethernet.py", line 127, in parse
    self.next = ethernet.parse_next(self, self.type, raw, ethernet.MIN_LEN)
  File "/home/abdirahman/pox/pox/lib/packet/ethernet.py", line 134, in parse_next
    return parser(raw[offset:], prev)
  File "/home/abdirahman/pox/pox/lib/packet/ipv4.py", line 93, in __init__
    self.parse(raw)
  File "/home/abdirahman/pox/pox/lib/packet/ipv4.py", line 158, in parse
    self.next = udp(raw=raw[self.hl*4:length], prev=self)
  File "/home/abdirahman/pox/pox/lib/packet/udp.py", line 68, in __init__
    self.parse(raw)
  File "/home/abdirahman/pox/pox/lib/packet/udp.py", line 100, in parse
    self.next = dhcp(raw=raw[udp.MIN_LEN:],prev=self)
  File "/home/abdirahman/pox/pox/lib/packet/dhcp.py", line 142, in __init__
    self.parse(raw)
  File "/home/abdirahman/pox/pox/lib/packet/dhcp.py", line 215, in parse
    self.parseOptions()
  File "/home/abdirahman/pox/pox/lib/packet/dhcp.py", line 232, in parseOptions
    self.parseOptionSegment(self._raw_options)
  File "/home/abdirahman/pox/pox/lib/packet/dhcp.py", line 248, in parseOptionSegment
    opt = ord(barr[ofs])
TypeError: ord() expected string of length 1, but int found

[MurphyMc]

I think you can probably just remove the ord.

This looks like it had been missed until now in the Python 3 (#192) transition.

If removing the ord fixes it, we should push it.

[Jaisaiarun]

After removing ord()
"ERROR:packet:(dns) parsing questions: sequence item 0: expected str instance, bytes found"
this error is shown . what should be done?

[MurphyMc]

I don't have a lot of time to work on this right now. The basic issue is a Python2/Python3 conversion problem that didn't get caught yet. Here are some options:

• Use the Python 2 version of POX. The fangtooth branch of my fork is the most up to date for Python 2.
• Fix it yourself. For hints, you could look through other recent commits which are marked as Python 3 conversion stuff relating to str/bytes. If you do this, it'd be great if you'd make your fix available so it can be incorporated into POX.
• Wait for me or someone else to fix it. You could facilitate this by:
  1. If there's a traceback instead of just the "sequence item 0" error message, post the full traceback.
  2. Posting a pcap capture that includes the DNS packet which causes the problem.

[Jaisaiarun]

I added b in join and it worked .
"def read_dns_name_from_index(cls, l, index):
retlist = []
next = cls._read_dns_name_from_index(l, index, retlist)
return (next + 1,b".".join(retlist))"

[MurphyMc]

I'd forgotten about this issue, but have made a bunch of fixes to DNS (including the problem above) in this branch of my fork: https://github.com/MurphyMc/pox/tree/gar-wip3

... that stuff should probably eventually all get upstreamed.

[SalarJamal]

Hi dears
does this issue effect the result of measuring RTT and Throughput of network working under Pox controller? or it can be neglected?

[RiedelNicolas]

Hey, firendly reminder to put this fix on main.

[MohsenBs]

The problem still persists

[MohsenBs]

I added b in join and it worked . "def read_dns_name_from_index(cls, l, index): retlist = [] next = cls._read_dns_name_from_index(l, index, retlist) return (next + 1,b".".join(retlist))"

Can you share withus the code of DHCP after removing ord and DNS code

[aperezleiras]

I had to both add that "b" in read_dns_name_from_index and remove the ord's in _read_dns_name_from_index to get rid of the problem

[MohsenBs]

I had to both add that "b" in read_dns_name_from_index and remove the ord's in _read_dns_name_from_index to get rid of the problem

I don't have enough experience to edit, I tried and the error still appears

Can you send the code files after modification to make DHCP work?

[aperezleiras]

I had to both add that "b" in read_dns_name_from_index and remove the ord's in _read_dns_name_from_index to get rid of the problem

I don't have enough experience to edit, I tried and the error still appears

Can you send the code files after modification to make DHCP work?

I don't know about the DHCP problem, but it fixed the DNS problem for me, maybe you can do what I did to dns.py in dhcp.py, just replace pox/pox/lib/packet/dns.py with the dns.py in this zip
dns.zip

[MohsenBs]

I had to both add that "b" in read_dns_name_from_index and remove the ord's in _read_dns_name_from_index to get rid of the problem

I don't have enough experience to edit, I tried and the error still appears
Can you send the code files after modification to make DHCP work?

I don't know about the DHCP problem, but it fixed the DNS problem for me, maybe you can do what I did to dns.py in dhcp.py, just replace pox/pox/lib/packet/dns.py with the dns.py in this zip dns.zip

Thanks for the help, I appreciate it

But the problem persists, I think from the DHCP file

---

TypeError: ord() expected string of length 1, but int found
ERROR:core:Exception while handling Connection!PacketIn...
Traceback (most recent call last):
File "/home/mohsen/pox/pox/lib/revent/revent.py", line 242, in raiseEventNoErrors
return self.raiseEvent(event, *args, **kw)
File "/home/mohsen/pox/pox/lib/revent/revent.py", line 295, in raiseEvent
rv = event._invoke(handler, *args, **kw)
File "/home/mohsen/pox/pox/lib/revent/revent.py", line 168, in _invoke
return handler(self, args, **kw)
File "/home/mohsen/pox/pox/forwarding/topo_proactive.py", line 382, in _handle_PacketIn
packet = event.parsed
File "/home/mohsen/pox/pox/openflow/init.py", line 193, in parsed
return self.parse()
File "/home/mohsen/pox/pox/openflow/init.py", line 185, in parse
self._parsed = ethernet(self.data)
File "/home/mohsen/pox/pox/lib/packet/ethernet.py", line 106, in init
self.parse(raw)
File "/home/mohsen/pox/pox/lib/packet/ethernet.py", line 127, in parse
self.next = ethernet.parse_next(self, self.type, raw, ethernet.MIN_LEN)
File "/home/mohsen/pox/pox/lib/packet/ethernet.py", line 134, in parse_next
return parser(raw[offset:], prev)
File "/home/mohsen/pox/pox/lib/packet/ipv4.py", line 93, in init
self.parse(raw)
File "/home/mohsen/pox/pox/lib/packet/ipv4.py", line 158, in parse
self.next = udp(raw=raw[self.hl4:length], prev=self)
File "/home/mohsen/pox/pox/lib/packet/udp.py", line 68, in init
self.parse(raw)
File "/home/mohsen/pox/pox/lib/packet/udp.py", line 100, in parse
self.next = dhcp(raw=raw[udp.MIN_LEN:],prev=self)
File "/home/mohsen/pox/pox/lib/packet/dhcp.py", line 142, in init
self.parse(raw)
File "/home/mohsen/pox/pox/lib/packet/dhcp.py", line 215, in parse
self.parseOptions()
File "/home/mohsen/pox/pox/lib/packet/dhcp.py", line 232, in parseOptions
self.parseOptionSegment(self._raw_options)
File "/home/mohsen/pox/pox/lib/packet/dhcp.py", line 248, in parseOptionSegment
opt = ord(barr[ofs])
TypeError: ord() expected string of length 1, but int found

[aperezleiras]

File "/home/mohsen/pox/pox/lib/packet/dhcp.py", line 248, in parseOptionSegment
opt = ord(barr[ofs])
TypeError: ord() expected string of length 1, but int found

Try editing that file, line 248, and just remove that ord call, so it says opt = barr[ofs], do the same with other "ord"s you see in that same function

[MurphyMc]

Just a note that you are using an old version of POX. I suspect this problem is fixed in the halosaur branch.

[MurphyMc]

The Selecting a Branch / Version section of the manual hasn't been updated for a while, but describes the POX versioning scheme and the procedure to select them.

[MohsenBs]

The Selecting a Branch / Version section of the manual hasn't been updated for a while, but describes the POX versioning scheme and the procedure to select them.

• I appreciate the answer, I think it works now
• after dhclient and dhclient -r commands the IP address is still the same on mininet hosts. How can change or renew with different IPs?

[MurphyMc]

File a new issue and include relevant information (such as the command line / configuration you are using).

[MohsenBs]

• after dhclient and dhclient -r commands the IP address is still the same on mininet hosts. How can change or renew with different IPs?

#282 (comment)

[cloudlakecho]

@Jaisaiarun Thanks for sharing the tip.
Would you check the code line of return (next + 1,b".".join(retlist))"? The " isn't pair. The last " should by typo?

[cloudlakecho]

@aperezleiras I try to apply your tip of removing ord in the "_read_dns_name_from_index" function. I see two code lines with ord:
     chunk_size = ord(l[index])
     offset = ( (ord(l[index]) & 0x3) << 8 ) | ord(l[index + 1])

These lines should be like:
     chunk_size = l[index]
     offset = ( (l[index] & 0x3) << 8 ) | l[index + 1]?

My git branch: "gar-experimental"

[MurphyMc]

Why not just upgrade to the halosaur branch, where this was fixed almost two years ago?

[cloudlakecho]

@MurphyMc Thanks for your suggestion. I will switch the branch to "halosaur" and check the message during runtime.