low level networking in python

[Maxim Veksler]

Hello,

I wish to do some low level network stuff using python.

I've googled somewhat and came up with pylibpcap[1], trouble is I
can't compile it on my Ubuntu 6.10 workstation. Can someone please
suggest a way to read some bits from random ports? I'm looking to
write a simple pen-testing tool that would try from one side
connecting to ports and from the other side sniff traffic to see on
what ports traffic is coming.

For pylibpcap I'm getting:

"""
hq4ever@lucky:~/development/personal/pylibpcap/pylibpcap-0.5.1$ python
setup.py build
running build
running build_ext
building '_pcapmodule' extension
swig -python -shadow -ISWIG -o pcap.c pcap.i
pcap.i:72: Warning(124): Specifying the language name in %typemap is
deprecated - use #ifdef SWIG<LANG> instead.
pcap.i:77: Warning(124): Specifying the language name in %typemap is
deprecated - use #ifdef SWIG<LANG> instead.
pcap.i:82: Warning(124): Specifying the language name in %typemap is
deprecated - use #ifdef SWIG<LANG> instead.
/usr/bin/python ./build-tools/docify.py pcap.c
/usr/bin/python ./build-tools/docify-shadow.py pcap.py
Traceback (most recent call last):
File "./build-tools/docify-shadow.py", line 30, in ?
raise 'source file doesn\'t look like swigged shadow class code'
source file doesn't look like swigged shadow class code
error: command '/usr/bin/python' failed with exit status 1
"""

[1] http://pylibpcap.sourceforge.net/
[2] http://py.vaults.ca/apyllo.py/126307487

 

[kyosohma]

Hello,

I wish to do some low level network stuff using python.

I've googled somewhat and came up with pylibpcap[1], trouble is I
can't compile it on my Ubuntu 6.10 workstation. Can someone please
suggest a way to read some bits from random ports? I'm looking to
write a simple pen-testing tool that would try from one side
connecting to ports and from the other side sniff traffic to see on
what ports traffic is coming.

For pylibpcap I'm getting:

"""
hq4ever@lucky:~/development/personal/pylibpcap/pylibpcap-0.5.1$ python
setup.py build
running build
running build_ext
building '_pcapmodule' extension
swig -python -shadow -ISWIG -o pcap.c pcap.i
pcap.i:72: Warning(124): Specifying the language name in %typemap is
deprecated - use #ifdef SWIG<LANG> instead.
pcap.i:77: Warning(124): Specifying the language name in %typemap is
deprecated - use #ifdef SWIG<LANG> instead.
pcap.i:82: Warning(124): Specifying the language name in %typemap is
deprecated - use #ifdef SWIG<LANG> instead.
/usr/bin/python ./build-tools/docify.py pcap.c
/usr/bin/python ./build-tools/docify-shadow.py pcap.py
Traceback (most recent call last):
File "./build-tools/docify-shadow.py", line 30, in ?
raise 'source file doesn\'t look like swigged shadow class code'
source file doesn't look like swigged shadow class code
error: command '/usr/bin/python' failed with exit status 1
"""

[1]http://pylibpcap.sourceforge.net/
[2]http://py.vaults.ca/apyllo.py/126307487

--
Cheers,
Maxim Veksler

"Free as in Freedom" - Do u GNU ?

I would assume you could use the socket module. This post details
someone else who opened ports with Python:

http://www.thescripts.com/forum/thread44280.html

Here's another resource using some python servers:

http://docs.python.org/lib/socket-example.html

Finally, a Socket programming howto:
http://www.amk.ca/python/howto/sockets/

I'm also told that the Twisted framework is excellent for this sort of
thing.

Mike

 

[Steve Holden]

Hello,

I wish to do some low level network stuff using python.

I've googled somewhat and came up with pylibpcap[1], trouble is I
can't compile it on my Ubuntu 6.10 workstation. Can someone please
suggest a way to read some bits from random ports? I'm looking to
write a simple pen-testing tool that would try from one side
connecting to ports and from the other side sniff traffic to see on
what ports traffic is coming.

For pylibpcap I'm getting:

"""
hq4ever@lucky:~/development/personal/pylibpcap/pylibpcap-0.5.1$ python
setup.py build
running build
running build_ext
building '_pcapmodule' extension
swig -python -shadow -ISWIG -o pcap.c pcap.i
pcap.i:72: Warning(124): Specifying the language name in %typemap is
deprecated - use #ifdef SWIG<LANG> instead.
pcap.i:77: Warning(124): Specifying the language name in %typemap is
deprecated - use #ifdef SWIG<LANG> instead.
pcap.i:82: Warning(124): Specifying the language name in %typemap is
deprecated - use #ifdef SWIG<LANG> instead.
/usr/bin/python ./build-tools/docify.py pcap.c
/usr/bin/python ./build-tools/docify-shadow.py pcap.py
Traceback (most recent call last):
File "./build-tools/docify-shadow.py", line 30, in ?
raise 'source file doesn\'t look like swigged shadow class code'
source file doesn't look like swigged shadow class code
error: command '/usr/bin/python' failed with exit status 1
"""

[1]http://pylibpcap.sourceforge.net/
[2]http://py.vaults.ca/apyllo.py/126307487

--
Cheers,
Maxim Veksler

"Free as in Freedom" - Do u GNU ?

I would assume you could use the socket module. This post details
someone else who opened ports with Python:

http://www.thescripts.com/forum/thread44280.html

Here's another resource using some python servers:

http://docs.python.org/lib/socket-example.html

Finally, a Socket programming howto:
http://www.amk.ca/python/howto/sockets/

I'm also told that the Twisted framework is excellent for this sort of
thing.

The problem with dealing with ports is that you'd have to open each port
individually. So the OP, I presume, is trying to capture packets
generically as they arrive at a particular point int he processing cycle
to avoid that necessity.

regards
Steve

 

[Maxim Veksler]

I would assume you could use the socket module. This post details
someone else who opened ports with Python:

http://www.thescripts.com/forum/thread44280.html

Here's another resource using some python servers:

http://docs.python.org/lib/socket-example.html

Finally, a Socket programming howto:
http://www.amk.ca/python/howto/sockets/

I'm also told that the Twisted framework is excellent for this sort of
thing.

Thanks for the heads-up. The sockets howto was great help.

I'm trying to bind a non-blocking socket, here is my code:
"""
#!/usr/bin/env python

import socket, select
from time import sleep

s_nb10000 = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s_nb10000.setblocking(0)

s_nb10000.bind(('192.168.2.106', 10002))
s_nb10000.listen(5)

while 1:
conn, addr = s_nb10000.accept()
ready_to_read, ready_to_write, in_error = select.select([conn], [], [], 0)
print (ready_to_read, ready_to_write, in_error)
sleep(100)

s_nb10000.close()
"""

And this is the exception I'm getting:
"""
python non_blocking_socket.py
Traceback (most recent call last):
File "non_blocking_socket.py", line 13, in ?
conn, addr = s_nb10000.accept()
File "/usr/lib/python2.4/socket.py", line 161, in accept
sock, addr = self._sock.accept()
socket.error: (11, 'Resource temporarily unavailable')
"""

What am I doing wrong here?

p.s.
I've looked at twisted before posting this post. I've seen they
impelement alot of application level protocols but I didn't see much
treatment for low level "raw" network data, not to mention that it's a
way way over kill for what I'm asking to achieve. Twisted does have a
subproject called "Twisted Pair: Low-level networking" but sadly it's
unmaintained and undocumented.

Mike

Maxim.

 

[Irmen de Jong]

I'm trying to bind a non-blocking socket, here is my code:
"""
#!/usr/bin/env python

import socket, select
from time import sleep

s_nb10000 = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s_nb10000.setblocking(0)

s_nb10000.bind(('192.168.2.106', 10002))
s_nb10000.listen(5)

while 1:
conn, addr = s_nb10000.accept()
ready_to_read, ready_to_write, in_error = select.select([conn], [],
[], 0)
print (ready_to_read, ready_to_write, in_error)
sleep(100)

s_nb10000.close()
"""

And this is the exception I'm getting:
"""
python non_blocking_socket.py
Traceback (most recent call last):
File "non_blocking_socket.py", line 13, in ?
conn, addr = s_nb10000.accept()
File "/usr/lib/python2.4/socket.py", line 161, in accept
sock, addr = self._sock.accept()
socket.error: (11, 'Resource temporarily unavailable')
"""

What am I doing wrong here?

Nothing.
Any operation on a non-blocking socket that is usually blocking
(this includes accept(), bind(), connect(), recv with MSG_WAITALL)
can possibly return a socket.error with errno set to EAGAIN.
('resource temporarily unavailable').
If this happens you should use a select() on the socket to
wait until it's done with the requested operation.

--Irmen

 

[billiejoex]

I wish to do some low level network stuff using python.

I've googled somewhat and came up with pylibpcap[1], trouble is I
can't compile it on my Ubuntu 6.10 workstation.

I would suggest pcapy:
http://oss.coresecurity.com/projects/pcapy.html
Higher level, easier Object-Oriented API and support for multi-
threading.
Here's an example showing a simple sniffer app:
http://oss.coresecurity.com/impacket/sniff.py
Anyway, what kind of 'low-level network stuff' we're talking about?

 

[Maxim Veksler]

I'm trying to bind a non-blocking socket, here is my code:
"""
#!/usr/bin/env python

import socket, select
from time import sleep

s_nb10000 = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s_nb10000.setblocking(0)

s_nb10000.bind(('192.168.2.106', 10002))
s_nb10000.listen(5)

while 1:
conn, addr = s_nb10000.accept()
ready_to_read, ready_to_write, in_error = select.select([conn], [],
[], 0)
print (ready_to_read, ready_to_write, in_error)
sleep(100)

s_nb10000.close()
"""

And this is the exception I'm getting:
"""
python non_blocking_socket.py
Traceback (most recent call last):
File "non_blocking_socket.py", line 13, in ?
conn, addr = s_nb10000.accept()
File "/usr/lib/python2.4/socket.py", line 161, in accept
sock, addr = self._sock.accept()
socket.error: (11, 'Resource temporarily unavailable')
"""

What am I doing wrong here?

Nothing.
Any operation on a non-blocking socket that is usually blocking
(this includes accept(), bind(), connect(), recv with MSG_WAITALL)
can possibly return a socket.error with errno set to EAGAIN.
('resource temporarily unavailable').
If this happens you should use a select() on the socket to
wait until it's done with the requested operation.

Hello everyone, I would like to thank you all for the helping tips so
far, with your help I managed to improve the previous code to not give
the error, I believe it's now working.

The non blocking echo socket code:
"""
#!/usr/bin/env python

import socket, select

s_nb10000 = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s_nb10000.setblocking(0)

s_nb10000.bind(('0.0.0.0', 10002))
s_nb10000.listen(5)

while 1:
ready_to_read, ready_to_write, in_error =
select.select([s_nb10000], [], [], 0)
if s_nb10000 in ready_to_read:
conn, addr = s_nb10000.accept()
while 1:
data = conn.recv(1024)
if not data: break
conn.send(data)
conn.close()

s_nb10000.close()
"""

--Irmen

Maxim.