fail2ban/utils/dns.py

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Python
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# This file is part of Fail2Ban.
#
# Fail2Ban is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# Fail2Ban is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Fail2Ban; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
# Author: Cyril Jaquier
#
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# $Revision: 1.8 $
__author__ = "Cyril Jaquier"
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__version__ = "$Revision: 1.8 $"
__date__ = "$Date: 2005/11/20 17:07:47 $"
__copyright__ = "Copyright (c) 2004 Cyril Jaquier"
__license__ = "GPL"
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import os, re, socket, struct
def dnsToIp(dns):
""" Convert a DNS into an IP address using the Python socket module.
Thanks to Kevin Drapel.
"""
try:
return socket.gethostbyname_ex(dns)[2]
except socket.gaierror:
return list()
def textToDns(text):
""" Search for possible DNS in an arbitrary text.
Thanks to Tom Pike.
"""
match = re.findall("(?:(?:\w|-)+\.){2,}\w+", text)
if match:
return match
else:
return []
def searchIP(text):
""" Search if an IP address if directly available and return
it.
"""
match = re.findall("(?:\d{1,3}\.){3}\d{1,3}", text)
if match:
return match
else:
return []
def isValidIP(str):
""" Return true if str is a valid IP
"""
s = str.split('/', 1)
try:
socket.inet_aton(s[0])
return True
except socket.error:
return False
def textToIp(text):
""" Return the IP of DNS found in a given text.
"""
ipList = list()
# Search for plain IP
plainIP = searchIP(text)
for element in plainIP:
if isValidIP(element):
ipList.append(element)
if not ipList:
# Try to get IP from possible DNS
dnsList = textToDns(text)
for element in dnsList:
dns = dnsToIp(element)
for e in dns:
ipList.append(e)
return ipList
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def cidr(i, n):
""" Convert an IP address string with a CIDR mask into a 32-bit
integer.
"""
# 32-bit IPv4 address mask
MASK = 0xFFFFFFFFL
return ~(MASK >> n) & MASK & addr2bin(i)
def addr2bin(str):
""" Convert a string IPv4 address into an unsigned integer.
"""
return struct.unpack("!L", socket.inet_aton(str))[0]
def bin2addr(addr):
""" Convert a numeric IPv4 address into string n.n.n.n form.
"""
return socket.inet_ntoa(struct.pack("!L", addr))