Python 3 support

[brifordwylie]

We'd like to have pypcap support Python3, so we'll need to make sure setup/install and functionality all works with Python3.

[sgould420]

@brifordwylie: I confirmed the problem when trying to import the module on python3 from PR #19. I am on OS X El Capitan, 10.11.5, with python 3.5.1.

Python 3.5.1 (default, Jan 19 2016, 14:01:03) 
[GCC 4.2.1 Compatible Apple LLVM 7.0.2 (clang-700.1.81)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import pcap
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: dlopen(/usr/local/lib/python3.5/site-packages/pcap.cpython-35m-darwin.so, 2): Symbol not found: _PyBuffer_FromMemory
  Referenced from: /usr/local/lib/python3.5/site-packages/pcap.cpython-35m-darwin.so
  Expected in: flat namespace
 in /usr/local/lib/python3.5/site-packages/pcap.cpython-35m-darwin.so
>>> 

Note: I installed by using pip3 download pypcap then tar -xvf pypcap-1.1.5.tar.gz, modified setup.py as in commit https://github.com/pynetwork/pypcap/pull/18/commits/10621117d44906898e21b50abb80d8a1f79e019e to add the parentheses for python3 style print function, and also changed the line 45 to lib_sub_dirs = [os.path.join('/usr', sub_dir) \ as in the comment from @phirestalker on https://github.com/dugsong/pypcap/issues/49, and then running sudo pip3 install ./pypcap-1.1.5 That second fix did work fine to solve the AttributeError: 'NoneType' object has no attribute 'rfind' error in python2 on the same system.

[plison]

I can also confirm that the installation with pip3 is broken!

[claycollier]

Python3 removed the buffer API that was used to build the C extensions for 2.7. I have a version of pcap.pyx for Python3 that works on my machine, but I'm not sure how to build a version that supports both Python3 and 2.7. It appears that all that needs to happen is to change the calls to PyBuffer_FromMemory() to PyMemoryView_FromMemory() and regenerate the .c file using cython, but I haven't done any deep testing because the test scripts have version issues as well (like no clean dpkt installer for Python3).

[hellais]

Python3 removed the buffer API that was used to build the C extensions for 2.7. I have a version of pcap.pyx for Python3 that works on my machine, but I'm not sure how to build a version that supports both Python3 and 2.7. It appears that all that needs to happen is to change the calls to PyBuffer_FromMemory() to PyMemoryView_FromMemory() and regenerate the .c file using cython, but I haven't done any deep testing because the test scripts have version issues as well (like no clean dpkt installer for Python3).

This is great!

Could you submit a PR with the changes you made to it and I can take a look at it. If it's not possible to have a c extension that works both on python2 and python3, we can build two versions of it and use one of the other in the setup.py depending on the detected version.

[nuald]

Fixed in #47. Need to verify across the various use-cases with the different Python versions though.

[lambdalisue]

When is feature/python3 merged to the master and uploaded to PyPI? I'm using that branch and seems ready. I'm looking forward.

[hellais]

When is feature/python3 merged to the master and uploaded to PyPI? I'm using that branch and seems ready. I'm looking forward.

Thanks for the input on that. I haven't gotten around to testing it extensively yet, but will try to bump it a bit up in my priorities and see if we can get something pushed sometime next week.

[lambdalisue]

Thanks! I'm lookin' forward it's on PyPI:)

[hellais]

This is implemented.