tcp_retrans_sources.py

#!/usr/bin/python
#GistID: 

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():
    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():

    content = _load()
    result = []
    for line in content:
        line_array = _remove_empty(line.split(' '))     # Split lines and remove empty spaces.
        retran = int(line_array[6], 16)
        if retran < 1:
            continue
        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]
        if line_array[3] == "03":
            continue
        else:
            state = STATE[line_array[3]]

        nline = [tcp_id, l_host+':'+l_port, r_host+':'+r_port, retran, state]
        result.append(nline)
    return result

if __name__ == '__main__':
    for conn in netstat():
        print conn