Murphy,
Exactly as you suggested. 3 changes did the trick.
* Added at Line 244 packet.dns:
elif r.qtype == 28:
assert isinstance(r.rddata, IPAddr6)
return s + r.rddata.toRaw()
* Changed Line 435 packet.dns:
return IPAddr6.from_raw(l[beg_index : beg_index + dlen])
* Added at line 521 (semi-arbitrary) addresses.py:
def toRaw (self):
return self.raw
Thanks for the help!
—Curtis
On Mar 11, 2014, at 11:13 PM, Murphy McCauley <[email protected]> wrote:
> On Mar 11, 2014, at 7:35 PM, Curtis Taylor <[email protected]> wrote:
>
>> Hi,
>>
>> I’m trying to parse and alter AAAA (IPv6) DNS responses with POX, but I get
>> the following error:
>> ��B�)'packet:(dns) parsing answers: Bad address format
>>
>> The error stems from around line 398 in addresses.py. At that point in the
>> execution, my IPv6 address (converted to hex from binary) is
>> 20010db8000000000000ff0000428329, which is correct. However, it appears that
>> POX is attempting to split, based on colons, but these shouldn’t be in the
>> binary representation of the IP -- (isinstance(addr, bytes) and not raw) is
>> True.
>
> I don't know what "binary representation" means in this context. Is this a
> string containing 32 hex characters? Or is it 16 raw bytes?
>
> The latter one (16 raw bytes) should be supported by IPAddr6 if it's passed
> into the constructor with raw=True (or using the from_raw() factory). The
> former isn't supported -- it needs to be a properly formatted IPv6 address
> (e.g., as per rfc5952), which contains colons.
>
> It seems like packet.dns maybe has a bug here where line 432 should use the
> from_raw() factory but doesn't. If you make that fix does that help?
>
>> I’ve attempted to alter addresses.py change addr from bytes to a IPv6 string
>> separated by colons (2001:0db8:0000:0000:0000:ff00:0042:8329), but I only
>> break things later down the line (dns.py for me). I also see nothing
>> irregular with the OpenFlow traffic to the controller.
>
> Can you elaborate on what breaks and how it breaks? Does it break in the dns
> class's hdr() method? If so, a quick guess is that putData() needs an if
> clause for qtype == 28 which is much like the one for qtype == 1.
>
>> My current setup:
>> POX - 0.2.0 (carp) - l3_learning (also shows parsing error as above)
>> Mininet with custom topology
>> BIND9 - the entry in question looks like "server1 IN AAAA
>> 2001:db8::ff00:42:8329”. Wireshark shows nothing wrong with the DNS
>> request/response.
>>
>> Any help would be appreciated.
>>
>> Cheers,
>> Curtis
>
