low level ethernet device access in linux

[Tom Brown]

Hi,

I have a windows application, written in delphi, that communicates to our
devices using raw ethernet frames. I am trying to port this application to
linux using python. However, when I try to open a socket, I get this error:

File "/home/tbrown/projects/discovery/trunk/comm.py", line 9, in __init__
self.s = socket(AF_PACKET, SOCK_RAW, proto)
File "/usr/local/lib/python2.5/socket.py", line 156, in __init__
_sock = _realsocket(family, type, proto)
socket.error: (1, 'Operation not permitted')

I understand that I am getting this error because I am running the application
as a user and not as root. I would like to be able to run this app. as a
user. Is there a way to create a socket without running the app. as root or
sudo? When I run the app. as root I get this error:

discovery.py: cannot connect to X server

Thanks,
Tom

 

[Grant Edwards]

I understand that I am getting this error because I am running
the application as a user and not as root. I would like to be
able to run this app. as a user. Is there a way to create a
socket without running the app. as root or sudo?

Yes.

According to the raw(7) man page:

ERRORS

EPERM The user doesn't have permission to open raw
sockets. Only pro- cesses with a effective user
ID of 0 or the CAP_NET_RAW attribute may do that.

Anticipating your next question:

$ man capabilities