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#!/usr/bin/python
# based on http://voorloopnul.com/blog/a-python-netstat-in-less-than-100-lines-of-code/
# added caching of glob for x10 speedup (additional x2 by omitting pid)
import pwd
import os
import glob
PROC_TCP = "/proc/net/tcp"
STATE = {
'01':'ESTABLISHED',
'02':'SYN_SENT',
'03':'SYN_RECV',
'04':'FIN_WAIT1',
'05':'FIN_WAIT2',
'06':'TIME_WAIT',
'07':'CLOSE',
'08':'CLOSE_WAIT',
'09':'LAST_ACK',
'0A':'LISTEN',
'0B':'CLOSING'
}
def _load():
''' Read the table of tcp connections & remove header '''
with open(PROC_TCP,'r') as f:
content = f.readlines()
content.pop(0)
return content
def _hex2dec(s):
return str(int(s,16))
def _ip(s):
ip = [(_hex2dec(s[6:8])),(_hex2dec(s[4:6])),(_hex2dec(s[2:4])),(_hex2dec(s[0:2]))]
return '.'.join(ip)
def _remove_empty(array):
return [x for x in array if x]
def _convert_ip_port(array):
host,port = array.split(':')
return _ip(host),_hex2dec(port)
def netstat(with_pid = True):
'''
Function to return a list with status of tcp connections at linux systems
To get pid of all network process running on system, you must run this script
as superuser
'''
pid_cache.clear()
content=_load()
result = []
for line in content:
line_array = _remove_empty(line.split(' ')) # Split lines and remove empty spaces.
l_host,l_port = _convert_ip_port(line_array[1]) # Convert ipaddress and port from hex to decimal.
r_host,r_port = _convert_ip_port(line_array[2])
tcp_id = line_array[0]
state = STATE.get(line_array[3])
uid = pwd.getpwuid(int(line_array[7]))[0] # Get user from UID.
inode = line_array[9] # Need the inode to get process pid.
if with_pid:
pid = _get_pid_of_inode(inode) # Get pid prom inode.
try: # try read the process name.
exe = os.readlink('/proc/' + pid + '/exe')
except:
exe = None
else:
pid = exe = None
result.append([tcp_id, uid, l_host, l_port, r_host, r_port, state, pid, exe])
pid_cache.clear()
return result
pid_cache = {}
def _get_pid_of_inode(inode):
'''
To retrieve the process pid, check every running process and look for one using
the given inode.
'''
if not pid_cache:
for fd in glob.glob('/proc/[0-9]*/fd/[0-9]*'):
try:
pid_cache[fd] = os.readlink(fd)
except:
pass
inode = '[' + inode + ']'
for key, val in pid_cache.items():
if inode in val:
return key.split('/')[2]
return None
if __name__ == '__main__':
for conn in netstat():
print(conn)
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