init

dhcp_basic_packet.py

@@ -0,0 +1,192 @@
+# pydhcplib
+# Copyright (C) 2008 Mathieu Ignacio -- mignacio@april.org
+#
+# This file is part of pydhcplib.
+# Pydhcplib 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 3 of the License, or
+# (at your option) any later version.
+#
+# This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
+
+import operator
+from struct import unpack
+from struct import pack
+from dhcp_constants import *
+import sys
+
+
+# DhcpPacket : base class to encode/decode dhcp packets.
+
+class DhcpBasicPacket:
+    def __init__(self):
+        self.packet_data = [0]*240
+        self.options_data = {}
+        self.packet_data[236:240] = MagicCookie
+        self.source_address = False
+        
+    def IsDhcpPacket(self):
+        if self.packet_data[236:240] != MagicCookie : return False
+        return True
+
+    # Check if variable is a list with int between 0 and 255
+    def CheckType(self,variable):
+        if type(variable) == list :
+            for each in variable :
+                if (type(each) != int)  or (each < 0) or (each > 255) :
+                    return False
+            return True
+        else : return False
+        
+
+    def DeleteOption(self,name):
+        # if name is a standard dhcp field
+        # Set field to 0
+        if DhcpFields.has_key(name) :
+            begin = DhcpFields[name][0]
+            end = DhcpFields[name][0]+DhcpFields[name][1]
+            self.packet_data[begin:end] = [0]*DhcpFields[name][1]
+            return True
+
+        # if name is a dhcp option
+        # delete option from self.option_data
+        elif self.options_data.has_key(name) :
+            # forget how to remove a key... try delete
+            self.options_data.__delitem__(name)
+            return True
+
+        return False
+
+    def GetOption(self,name):
+        if DhcpFields.has_key(name) :
+            option_info = DhcpFields[name]
+            return self.packet_data[option_info[0]:option_info[0]+option_info[1]]
+
+        elif self.options_data.has_key(name) :
+            return self.options_data[name]
+
+        return []
+        
+
+    def SetOption(self,name,value):
+
+        # Basic value checking :
+        # has value list a correct length
+        
+        # if name is a standard dhcp field
+        if DhcpFields.has_key(name) :
+            if len(value) != DhcpFields[name][1] :
+                sys.stderr.write( "pydhcplib.dhcp_basic_packet.setoption error, bad option length : "+name+" Expected: "+str(DhcpFields[name][1])+" Got: "+str(len(value)))
+                return False
+            begin = DhcpFields[name][0]
+            end = DhcpFields[name][0]+DhcpFields[name][1]
+            self.packet_data[begin:end] = value
+            return True
+
+        # if name is a dhcp option
+        elif DhcpOptions.has_key(name) :
+
+            # fields_specs : {'option_code':fixed_length,minimum_length,multiple}
+            # if fixed_length == 0 : minimum_length and multiple apply
+            # else : forget minimum_length and multiple 
+            # multiple : length MUST be a multiple of 'multiple'
+            # FIXME : this definition should'nt be in dhcp_constants ?
+            fields_specs = { "ipv4":[4,0,1], "ipv4+":[0,4,4],
+                             "string":[0,0,1], "bool":[1,0,1],
+                             "char":[1,0,1], "16-bits":[2,0,1],
+                             "32-bits":[4,0,1], "identifier":[0,2,1],
+                             "RFC3397":[0,4,1],"none":[0,0,1],"char+":[0,1,1]
+                             }
+            
+            specs = fields_specs[DhcpOptionsTypes[DhcpOptions[name]]]
+            length = len(value)
+            if (specs[0]!=0 and specs==length) or (specs[1]<=length and length%specs[2]==0):
+                self.options_data[name] = value
+                return True
+            else :
+                return False
+
+        sys.stderr.write( "pydhcplib.dhcp_basic_packet.setoption error : unknown option "+name)
+        return False
+
+
+
+    def IsOption(self,name):
+        if self.options_data.has_key(name) : return True
+        elif DhcpFields.has_key(name) : return True
+        else : return False
+
+    # Encode Packet and return it
+    def EncodePacket(self):
+
+        # MUST set options in order to respect the RFC (see router option)
+        order = {}
+
+        for each in self.options_data.keys() :
+            order[DhcpOptions[each]] = []
+            order[DhcpOptions[each]].append(DhcpOptions[each])
+            order[DhcpOptions[each]].append(len(self.options_data[each]))
+            order[DhcpOptions[each]] += self.options_data[each]
+            
+        options = []
+
+        for each in sorted(order.keys()) : options += (order[each])
+
+        packet = self.packet_data[:240] + options
+        packet.append(255) # add end option
+        pack_fmt = str(len(packet))+"c"
+
+        packet = map(chr,packet)
+        
+        return pack(pack_fmt,*packet)
+
+
+    # Insert packet in the object
+    def DecodePacket(self,data,debug=False):
+        self.packet_data = []
+        self.options_data = {}
+
+        if (not data) : return False
+        # we transform all data to int list
+        unpack_fmt = str(len(data)) + "c"
+        for i in unpack(unpack_fmt,data):
+            self.packet_data.append(ord(i))
+
+        # Some servers or clients don't place magic cookie immediately
+        # after headers and begin options fields only after magic.
+        # These 4 lines search magic cookie and begin iterator after.
+        iterator = 236
+        end_iterator = len(self.packet_data)
+        while ( self.packet_data[iterator:iterator+4] != MagicCookie and iterator < end_iterator) :
+            iterator += 1
+        iterator += 4
+        
+        # parse extended options
+
+        while iterator < end_iterator :
+            if self.packet_data[iterator] == 0 : # pad option
+                opt_first = iterator+1
+                iterator += 1
+
+            elif self.packet_data[iterator] == 255 :
+                self.packet_data = self.packet_data[:240] # base packet length without magic cookie
+                return
+                
+            elif DhcpOptionsTypes.has_key(self.packet_data[iterator]) and self.packet_data[iterator]!= 255:
+                opt_len = self.packet_data[iterator+1]
+                opt_first = iterator+1
+                self.options_data[DhcpOptionsList[self.packet_data[iterator]]] = self.packet_data[opt_first+1:opt_len+opt_first+1]
+                iterator += self.packet_data[opt_first] + 2
+            else :
+                opt_first = iterator+1
+                iterator += self.packet_data[opt_first] + 2
+
+        # cut packet_data to remove options
+        
+        self.packet_data = self.packet_data[:240] # base packet length with magic cookie

dhcp_client.py

@@ -0,0 +1,54 @@
+#! /usr/bin/env python
+from dhcp_packet import *
+import socket
+import random
+from type_hwmac import *
+import pcap
+import dpkt
+import binascii
+import time
+
+class DhcpClient:
+  def send_packet(self, mac, iface, xid):
+    dhcp = DhcpPacket()
+    dhcp.SetOption('op', [1]);
+    dhcp.SetOption('htype', [1]);
+    dhcp.SetOption('hlen', [6]);
+    dhcp.SetOption('xid', xid);
+    dhcp.SetOption('chaddr', hwmac(mac).list());
+    dhcp.SetOption('dhcp_message_type', [1]);
+    dhcp.SetOption('parameter_request_list', [12]);
+
+    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+    s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+    s.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
+    s.setsockopt(socket.SOL_SOCKET, 25, iface + '\0')
+    s.bind(('', 68))
+    s.sendto(dhcp.EncodePacket(), ('255.255.255.255', 67))
+    s.close()
+
+
+  def get_offer(self, mac, iface, timeout = 10):
+    pc = pcap.pcap(name=iface)
+    pc.setfilter('udp and udp src port 67 and udp dst port 68')
+    xid = [random.randrange(255), random.randrange(255),
+        random.randrange(255), random.randrange(255)]
+    self.send_packet(mac, iface, xid)
+    pc.setnonblock()
+    start = time.time()
+    while True:
+        try:
+            for pkt in pc.readpkts():
+                eth = dpkt.ethernet.Ethernet(pkt[1])
+                dh = DhcpPacket()
+                dh.DecodePacket(eth.data.data.data)
+                if (dh.GetOption('xid') == xid and
+                    dh.GetOption('op') == [2] and
+                    dh.GetOption('dhcp_message_type') == [2]):
+                    return dh
+        except:
+            pass
+        time.sleep(0.5)
+        if time.time() - start >= timeout:
+            return None
+

dhcp_constants.py

@@ -0,0 +1,414 @@
+# pydhcplib
+# Copyright (C) 2008 Mathieu Ignacio -- mignacio@april.org
+#
+# This file is part of pydhcplib.
+# Pydhcplib 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 3 of the License, or
+# (at your option) any later version.
+#
+# This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
+
+
+MagicCookie = [99,130,83,99]
+PyDhcpLibVersion = '0.6'
+
+# DhcpBaseOptions = '{fieldname':[location,length]}
+DhcpFields = {'op':[0,1],
+                     'htype':[1,1],
+                     'hlen':[2,1],
+                     'hops':[3,1],
+                     'xid':[4,4],
+                     'secs':[8,2],
+                     'flags':[10,2],
+                     'ciaddr':[12,4],
+                     'yiaddr':[16,4],
+                     'siaddr':[20,4],
+                     'giaddr':[24,4],
+                     'chaddr':[28,16],
+                     'sname':[44,64],
+                     'file':[108,128]
+                     }
+DhcpFieldsName = { 'op' : { '0': 'ERROR_UNDEF', '1' : 'BOOTREQUEST' , '2' : 'BOOTREPLY'},
+                   'dhcp_message_type' : { '0': 'ERROR_UNDEF', '1': 'DHCP_DISCOVER', '2': 'DHCP_OFFER',
+                                           '3' : 'DHCP_REQUEST','4':'DHCP_DECLINE', '5': 'DHCP_ACK', '6': 'DHCP_NACK',
+                                           '7': 'DHCP_RELEASE', '8' : 'DHCP_INFORM' }
+                   }
+DhcpNames = { 'ERROR_UNDEF':0 , 'BOOTREQUEST':1 , 'BOOTREPLY':2 ,
+              'DHCP_DISCOVER':1 , 'DHCP_OFFER':2 , 'DHCP_REQUEST':3 ,
+              'DHCP_DECLINE':4 , 'DHCP_ACK':5 , 'DHCP_NACK':6 ,
+              'DHCP_RELEASE':7 , 'DHCP_INFORM':8 }
+
+DhcpFieldsTypes = {'op':"int",
+                     'htype':"int",
+                     'hlen':"int",
+                     'hops':"int",
+                     'xid':"int4",
+                     'secs':"int2",
+                     'flags':"int2",
+                     'ciaddr':"ipv4",
+                     'yiaddr':"ipv4",
+                     'siaddr':"ipv4",
+                     'giaddr':"ipv4",
+                     'chaddr':"hwmac",
+                     'sname':"str",
+                     'file':"str"
+                     }
+
+# DhcpOptions = 'option_name':option_code
+DhcpOptions = {'pad':0,
+
+               # Vendor Extension
+               'subnet_mask':1,'time_offset':2,
+               'router':3,'time_server':4,'name_server':5,
+               'domain_name_server':6,'log_server':7,
+               'cookie_server':8,'lpr_server':9,
+               'impress_server':10,'resource_location_server':11,
+               'host_name':12,'boot_file':13,'merit_dump_file':14,
+               'domain_name':15,'swap_server':16,'root_path':17,'extensions_path':18,
+
+               # IP layer parameters per host
+               'ip_forwarding':19,'nonlocal_source_rooting':20,
+               'policy_filter':21,'maximum_datagram_reassembly_size':22,
+               'default_ip_time-to-live':23,'path_mtu_aging_timeout':24,
+               'path_mtu_table':25,
+
+               # IP layer parameters per interface
+               'interface_mtu':26,'all_subnets_are_local':27,
+               'broadcast_address':28,'perform_mask_discovery':29,
+               'mask_supplier':30,'perform_router_discovery':31,
+               'routeur_solicitation_address':32,'static_route':33,
+
+               # link layer parameters per interface
+               'trailer_encapsulation':34,'arp_cache_timeout':35,
+               'ethernet_encapsulation':36,
+
+               # TCP parameters
+               'tcp_default_ttl':37,'tcp_keepalive_interval':38,
+               'tcp_keepalive_garbage':39,
+
+               # Applications and service parameters
+               'nis_domain':40,
+               'nis_servers':41,
+               'ntp_servers':42,
+               'vendor_specific':43,
+               'nbns':44,
+               'nbdd':45,'nb_node_type':46,
+               'nb_scope':47,'x_window_system_font_server':48,
+               'x_window_system_display_manager':49,
+
+               # DHCP extensions
+               'request_ip_address':50,
+               'ip_address_lease_time':51,
+               'overload':52,
+               'dhcp_message_type':53,
+               'server_identifier':54,
+               'parameter_request_list':55,
+               'message':56,
+               'maximum_dhcp_message_size':57,
+               'renewal_time_value':58,
+               'rebinding_time_value':59,
+               'vendor_class':60,
+               'client_identifier':61,
+
+               # Add from RFC 2132 
+               'netware_ip_domain_name':62,
+               'netware_ip_sub_options':63,
+               
+               'nis+_domain':64,
+               'nis+_servers':65,
+               'tftp_server_name':66,
+               'bootfile_name':67,
+               'mobile_ip_home_agent':68,
+               'smtp_servers':69,
+               'pop_servers':70,
+               'nntp_servers':71,
+               'default_www_server':72,
+               'default_finger_server':73,
+               'default_irc_server':74,
+               'streettalk_server':75,
+               'streettalk_directory_assistance_server':76,
+
+               'user_class':77,
+               'directory_agent':78,
+               'service_scope':79,
+               'rapid_commit':80,
+
+               'client_fqdn':81,
+               'relay_agent':82,
+               'internet_storage_name_service':83,
+               '84':84,
+               'nds_server':85,
+               'nds_tree_name':86,
+               'nds_context':87,
+               '88':88,
+               '89':89,
+               'authentication':90,
+               'client_last_transaction_time':91,
+               'associated_ip':92,
+               'client_system':93,
+               'client_ndi':94,
+               'ldap':95,
+               'unassigned':96,
+               'uuid_guid':97,
+               'open_group_user_auth':98,
+               'unassigned':99,
+               'unassigned':100,
+               'unassigned':101,
+               'unassigned':102,
+               'unassigned':103,
+               'unassigned':104,
+               'unassigned':105,
+               'unassigned':106,
+               'unassigned':107,
+               'unassigned':108,
+               'unassigned':109,
+               'unassigned':110,
+               'unassigned':111,
+               'netinfo_address':112,
+               'netinfo_tag':113,
+               'url':114,
+               'unassigned':115,
+               'auto_config':116,
+               'name_service_search':117,
+               'subnet_selection':118,
+               'domain_search':119,
+               'sip_servers':120,
+               'classless_static_route':121,
+               'cablelabs_client_configuration':122,
+               'geoconf':123,
+               'vendor_class':124,
+               'vendor_specific':125,
+               '126':126,'127':127,'128':128,'129':129,
+               '130':130,'131':131,'132':132,'133':133,
+               '134':134,'135':135,'136':136,'137':137,
+               '138':138,'139':139,'140':140,'141':141,
+               '142':142,'143':143,'144':144,'145':145,
+               '146':146,'147':147,'148':148,'149':149,
+               '150':150,'151':151,'152':152,'153':153,
+               '154':154,'155':155,'156':156,'157':157,
+               '158':158,'159':159,'160':160,'161':161,
+               '162':162,'163':163,'164':164,'165':165,
+               '166':166,'167':167,'168':168,'169':169,
+               '170':170,'171':171,'172':172,'173':173,
+               '174':174,'175':175,'176':176,'177':177,
+               '178':178,'179':179,'180':180,'181':181,
+               '182':182,'183':183,'184':184,'185':185,
+               '186':186,'187':187,'188':188,'189':189,
+               '190':190,'191':191,'192':192,'193':193,
+               '194':194,'195':195,'196':196,'197':197,
+               '198':198,'199':199,'200':200,'201':201,
+               '202':202,'203':203,'204':204,'205':205,
+               '206':206,'207':207,'208':208,'209':209,
+               '210':210,'211':211,'212':212,'213':213,
+               '214':214,'215':215,'216':216,'217':217,
+               '218':218,'219':219,'220':220,'221':221,
+               '222':222,'223':223,'224':224,'225':225,
+               '226':226,'227':227,'228':228,'229':229,
+               '230':230,'231':231,'232':232,'233':233,
+               '234':234,'235':235,'236':236,'237':237,
+               '238':238,'239':239,'240':240,'241':241,
+               '242':242,'243':243,'244':244,'245':245,
+               '246':246,'247':247,'248':248,'249':249,
+               '250':250,'251':251,'252':252,'253':253,
+               '254':254,'end':255
+
+               }
+
+# DhcpOptionsList : reverse of DhcpOptions
+DhcpOptionsList = ['pad',
+
+                   # Vendor Extension
+                   'subnet_mask','time_offset',
+                   'router','time_server','name_server',
+                   'domain_name_server','log_server',
+                   'cookie_server','lpr_server',
+                   'impress_server','resource_location_server',
+                   'host_name','boot_file','merit_dump_file',
+                   'domain_name','swap_server','root_path','extensions_path',
+                   
+                   # IP layer parameters per host
+                   'ip_forwarding','nonlocal_source_rooting',
+                   'policy_filter','maximum_datagram_reassembly_size',
+                   'default_ip_time-to-live','path_mtu_aging_timeout',
+                   'path_mtu_table',
+                   
+                   # IP layer parameters per interface
+                   'interface_mtu','all_subnets_are_local',
+                   'broadcast_address','perform_mask_discovery',
+                   'mask_supplier','perform_router_discovery',
+                   'routeur_solicitation_address','static_route',
+                   
+                   # link layer parameters per interface
+                   'trailer_encapsulation','arp_cache_timeout',
+                   'ethernet_encapsulation',
+                   
+                   # TCP parameters
+                   'tcp_default_ttl','tcp_keepalive_interval',
+                   'tcp_keepalive_garbage',
+                   
+                   # Applications and service parameters
+                   'nis_domain',
+                   'nis_servers',
+                   'ntp_servers',
+                   'vendor_specific','nbns',
+                   'nbdd','nd_node_type',
+                   'nb_scope','x_window_system_font_server',
+                   'x_window_system_display_manager',
+
+                   # DHCP extensions
+                   'request_ip_address',
+                   'ip_address_lease_time',
+                   'overload',
+                   'dhcp_message_type',
+                   'server_identifier',
+                   'parameter_request_list',
+                   'message',
+                   'maximum_dhcp_message_size',
+                   'renewal_time_value',
+                   'rebinding_time_value',
+                   'vendor_class',
+                   'client_identifier',
+                   
+
+                   # adds from RFC 2132,2242
+                   'netware_ip_domain_name',
+                   'netware_ip_sub_options',
+                   'nis+_domain',
+                   'nis+_servers',
+                   'tftp_server_name',
+                   'bootfile_name',
+                   'mobile_ip_home_agent',
+                   'smtp_servers',
+                   'pop_servers',
+                   'nntp_servers',
+                   'default_www_server',
+                   'default_finger_server',
+                   'default_irc_server',
+                   'streettalk_server',
+                   'streettalk_directory_assistance_server',
+                   'user_class','directory_agent','service_scope',
+
+                   # 80
+                   'rapid_commit','client_fqdn','relay_agent',
+                   'internet_storage_name_service',
+                   '84',
+                   'nds_server','nds_tree_name','nds_context',
+                   '88','89',
+
+                   #90
+                   'authentication',
+                   'client_last_transaction_time','associated_ip', #RFC 4388
+                   'client_system', 'client_ndi', #RFC 3679
+                   'ldap','unassigned','uuid_guid', #RFC 3679
+                   'open_group_user_auth', #RFC 2485
+
+                   # 99->115 RFC3679 
+                   'unassigned','unassigned','unassigned',
+                   'unassigned','unassigned','unassigned',
+                   'unassigned','unassigned','unassigned',
+                   'unassigned','unassigned','unassigned',
+                   'unassigned','netinfo_address','netinfo_tag',
+                   'url','unassigned',
+
+                   #116
+                   'auto_config','name_service_search','subnet_selection',
+                   'domain_search','sip_servers','classless_static_route',
+                   'cablelabs_client_configuration','geoconf',
+
+                   #124
+                   'vendor_class', 'vendor_specific',
+
+                   '126','127','128','129',
+                   '130','131','132','133','134','135','136','137','138','139',
+                   '140','141','142','143','144','145','146','147','148','149',
+                   '150','151','152','153','154','155','156','157','158','159',
+                   '160','161','162','163','164','165','166','167','168','169',
+                   '170','171','172','173','174','175','176','177','178','179',
+                   '180','181','182','183','184','185','186','187','188','189',
+                   '190','191','192','193','194','195','196','197','198','199',
+                   '200','201','202','203','204','205','206','207','208','209',
+                   '210','211','212','213','214','215','216','217','218','219',
+                   '220','221','222','223','224','225','226','227','228','229',
+                   '230','231','232','233','234','235','236','237','238','239',
+                   '240','241','242','243','244','245','246','247','248','249',
+                   '250','251','252','253','254',
+
+                   'end'
+                   ] 
+
+
+# See http://www.iana.org/assignments/bootp-dhcp-parameters
+# FIXME : verify all ipv4+ options, somes are 32 bits...
+
+DhcpOptionsTypes = {0:"none", 1:"ipv4", 2:"ipv4", 3:"ipv4+", 
+                    4:"ipv4+", 5:"ipv4+", 6:"ipv4+", 7:"ipv4+", 
+                    8:"ipv4+", 9:"ipv4+", 10:"ipv4+", 11:"ipv4+", 
+                    12:"string", 13:"16-bits", 14:"string", 15:"string", 
+                    16:"ipv4", 17:"string", 18:"string", 19:"bool", 
+                    20:"bool", 21:"ipv4+", 22:"16-bits", 23:"char", 
+                    24:"ipv4", 25:"16-bits", 26:"16-bits", 27:"bool", 
+                    28:"ipv4", 29:"bool", 30:"bool", 31:"bool", 
+                    32:"ipv4", 33:"ipv4+", 34:"bool", 35:"32-bits", 
+                    36:"bool", 37:"char", 38:"32-bits", 39:"bool", 
+                    40:"string", 41:"ipv4+", 42:"ipv4+", 43:"string", 
+                    44:"ipv4+", 45:"ipv4+", 46:"char", 47:"string", 
+                    48:"ipv4+", 49:"ipv4+", 50:"ipv4", 51:"32-bits", 
+                    52:"char", 53:"char", 54:"32-bits", 55:"char+", 
+                    56:"string", 57:"16-bits", 58:"32-bits", 59:"32-bits", 
+                    60:"string", 61:"identifier", 62:"string", 63:"RFC2242", 
+                    64:"string", 65:"ipv4+", 66:"string", 67:"string", 
+                    68:"ipv4", 69:"ipv4+", 70:"ipv4+", 71:"ipv4+",                     
+                    72:"ipv4+", 73:"ipv4+", 74:"ipv4+", 75:"ipv4+", 
+                    76:"ipv4+", 77:"RFC3004", 78:"RFC2610", 79:"RFC2610", 
+                    80:"null", 81:"string", 82:"RFC3046", 83:"RFC4174", 
+                    84:"Unassigned", 85:"ipv4+", 86:"RFC2241", 87:"RFC2241", 
+                    88:"Unassigned", 89:"Unassigned", 90:"RFC3118", 91:"RFC4388", 
+                    92:"ipv4+", 93:"Unassigned", 94:"Unassigned", 95:"Unassigned", 
+                    96:"Unassigned", 97:"Unassigned", 98:"string", 99:"Unassigned", 
+                    100:"Unassigned", 101:"Unassigned", 102:"Unassigned", 103:"Unassigned", 
+                    104:"Unassigned", 105:"Unassigned", 106:"Unassigned", 107:"Unassigned", 
+                    108:"Unassigned", 109:"Unassigned", 110:"Unassigned", 111:"Unassigned", 
+                    112:"Unassigned", 113:"Unassigned", 114:"Unassigned", 115:"Unassigned", 
+                    116:"char", 117:"RFC2937", 118:"ipv4", 119:"RFC3397", 
+                    120:"RFC3361",
+
+                    #TODO
+                    121:"Unassigned", 122:"Unassigned", 123:"Unassigned", 
+                    124:"Unassigned", 125:"Unassigned", 126:"Unassigned", 127:"Unassigned", 
+                    128:"Unassigned", 129:"Unassigned", 130:"Unassigned", 131:"Unassigned", 
+                    132:"Unassigned", 133:"Unassigned", 134:"Unassigned", 135:"Unassigned", 
+                    136:"Unassigned", 137:"Unassigned", 138:"Unassigned", 139:"Unassigned", 
+                    140:"Unassigned", 141:"Unassigned", 142:"Unassigned", 143:"Unassigned", 
+                    144:"Unassigned", 145:"Unassigned", 146:"Unassigned", 147:"Unassigned", 
+                    148:"Unassigned", 149:"Unassigned", 150:"Unassigned", 151:"Unassigned", 
+                    152:"Unassigned", 153:"Unassigned", 154:"Unassigned", 155:"Unassigned", 
+                    156:"Unassigned", 157:"Unassigned", 158:"Unassigned", 159:"Unassigned", 
+                    160:"Unassigned", 161:"Unassigned", 162:"Unassigned", 163:"Unassigned", 
+                    164:"Unassigned", 165:"Unassigned", 166:"Unassigned", 167:"Unassigned", 
+                    168:"Unassigned", 169:"Unassigned", 170:"Unassigned", 171:"Unassigned", 
+                    172:"Unassigned", 173:"Unassigned", 174:"Unassigned", 175:"Unassigned", 
+                    176:"Unassigned", 177:"Unassigned", 178:"Unassigned", 179:"Unassigned", 
+                    180:"Unassigned", 181:"Unassigned", 182:"Unassigned", 183:"Unassigned", 
+                    184:"Unassigned", 185:"Unassigned", 186:"Unassigned", 187:"Unassigned", 
+                    188:"Unassigned", 189:"Unassigned", 190:"Unassigned", 191:"Unassigned", 
+                    192:"Unassigned", 193:"Unassigned", 194:"Unassigned", 195:"Unassigned", 
+                    196:"Unassigned", 197:"Unassigned", 198:"Unassigned", 199:"Unassigned", 
+                    200:"Unassigned", 201:"Unassigned", 202:"Unassigned", 203:"Unassigned", 
+                    204:"Unassigned", 205:"Unassigned", 206:"Unassigned", 207:"Unassigned", 
+                    208:"Unassigned", 209:"Unassigned", 210:"Unassigned", 211:"Unassigned", 
+                    212:"Unassigned", 213:"Unassigned", 214:"Unassigned", 215:"Unassigned", 
+                    216:"Unassigned", 217:"Unassigned", 218:"Unassigned", 219:"Unassigned", 
+                    220:"Unassigned", 221:"Unassigned", 222:"Unassigned", 223:"Unassigned", 
+                    224:"Unassigned", 225:"Unassigned", 226:"Unassigned", 227:"Unassigned", 
+                    228:"Unassigned", 229:"Unassigned", 230:"Unassigned", 231:"Unassigned", 
+                    232:"Unassigned", 233:"Unassigned", 234:"Unassigned", 235:"Unassigned", 
+                    236:"Unassigned", 237:"Unassigned", 238:"Unassigned", 239:"Unassigned", 
+                    240:"Unassigned", 241:"Unassigned", 242:"Unassigned", 243:"Unassigned", 
+                    244:"Unassigned", 245:"Unassigned"}

dhcp_packet.py

@@ -0,0 +1,368 @@
+# pydhcplib
+# Copyright (C) 2008 Mathieu Ignacio -- mignacio@april.org
+#
+# This file is part of pydhcplib.
+# Pydhcplib 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 3 of the License, or
+# (at your option) any later version.
+#
+# This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
+
+import operator
+from struct import unpack
+from struct import pack
+from dhcp_basic_packet import *
+from dhcp_constants import *
+from type_ipv4 import ipv4
+from type_strlist import strlist
+from type_hwmac import hwmac
+import sys
+
+class DhcpPacket(DhcpBasicPacket):
+    def str(self):
+        # Process headers : 
+        printable_data = "# Header fields\n"
+
+        op = self.packet_data[DhcpFields['op'][0]:DhcpFields['op'][0]+DhcpFields['op'][1]]
+        printable_data += "op : " + DhcpFieldsName['op'][str(op[0])] + "\n"
+
+        
+        for opt in  ['htype','hlen','hops','xid','secs','flags',
+                     'ciaddr','yiaddr','siaddr','giaddr','chaddr','sname','file'] :
+            begin = DhcpFields[opt][0]
+            end = DhcpFields[opt][0]+DhcpFields[opt][1]
+            data = self.packet_data[begin:end]
+            result = ''
+            if DhcpFieldsTypes[opt] == "int" : result = str(data[0])
+            elif DhcpFieldsTypes[opt] == "int2" : result = str(data[0]*256+data[1])
+            elif DhcpFieldsTypes[opt] == "int4" : result = str(ipv4(data).int())
+            elif DhcpFieldsTypes[opt] == "str" :
+                for each in data :
+                    if each != 0 : result += chr(each)
+                    else : break
+
+            elif DhcpFieldsTypes[opt] == "ipv4" : result = ipv4(data).str()
+            elif DhcpFieldsTypes[opt] == "hwmac" :
+                result = []
+                hexsym = ['0','1','2','3','4','5','6','7','8','9','a','b','c','d','e','f']
+                for iterator in range(6) :
+                    result += [str(hexsym[data[iterator]/16]+hexsym[data[iterator]%16])]
+
+                result = ':'.join(result)
+
+            printable_data += opt+" : "+result  + "\n"
+
+        # Process options : 
+        printable_data += "# Options fields\n"
+
+        for opt in self.options_data.keys():
+            data = self.options_data[opt]
+            result = ""
+            optnum  = DhcpOptions[opt]
+            if opt=='dhcp_message_type' : result = DhcpFieldsName['dhcp_message_type'][str(data[0])]
+            elif DhcpOptionsTypes[optnum] == "char" : result = str(data[0])
+            elif DhcpOptionsTypes[optnum] == "16-bits" : result = str(data[0]*256+data[0])
+            elif DhcpOptionsTypes[optnum] == "32-bits" : result = str(ipv4(data).int())
+            elif DhcpOptionsTypes[optnum] == "string" :
+                for each in data :
+                    if each != 0 : result += chr(each)
+                    else : break
+        
+            elif DhcpOptionsTypes[optnum] == "ipv4" : result = ipv4(data).str()
+            elif DhcpOptionsTypes[optnum] == "ipv4+" :
+                for i in range(0,len(data),4) :
+                    if len(data[i:i+4]) == 4 :
+                        result += ipv4(data[i:i+4]).str() + " - "
+            elif DhcpOptionsTypes[optnum] == "char+" :
+                if optnum == 55 : # parameter_request_list
+                    result = ','.join([DhcpOptionsList[each] for each in data])
+                else : result += str(data)
+                
+            printable_data += opt + " : " + result + "\n"
+
+        return printable_data
+
+    def AddLine(self,_string) :
+        (parameter,junk,value) = _string.partition(':')
+        parameter = parameter.strip()
+        # If value begin with a whitespace, remove it, leave others
+        if len(value)>0 and value[0] == ' ' : value = value[1:]
+        value = self._OptionsToBinary(parameter,value)
+        if value : self.SetOption(parameter,value)
+
+    def _OptionsToBinary(self,parameter,value) :
+        # Transform textual data into dhcp binary data
+
+        p = parameter.strip()
+        # 1- Search for header informations or specific parameter
+        if p == 'op' or p == 'htype' :
+            value = value.strip()
+            if value.isdigit() : return [int(value)]
+            try :
+                value = DhcpNames[value.strip()]
+                return [value]
+            except KeyError :
+                return [0]
+
+        elif p == 'hlen' or p == 'hops' :
+            try :
+                value = int(value)
+                return [value]
+            except ValueError :
+                return [0]
+
+        elif p == 'secs' or p == 'flags' :
+            try :
+                value = ipv4(int(value)).list()
+            except ValueError :
+                value = [0,0,0,0]
+
+            return value[2:]
+
+        elif p == 'xid' :
+            try :
+                value = ipv4(int(value)).list()
+            except ValueError :
+                value = [0,0,0,0]
+            return value
+
+        elif p == 'ciaddr' or p == 'yiaddr' or p == 'siaddr' or p == 'giaddr' :
+            try :
+                ip = ipv4(value).list()
+            except ValueError :
+                ip = [0,0,0,0]
+            return ip
+        
+        elif p == 'chaddr' :
+            try:
+                value = hwmac(value).list()+[0]*10
+            except ValueError,TypeError :
+                value = [0]*16
+            return value
+            
+        elif p == 'sname' :
+            return
+        elif p == 'file' :
+            return
+        elif p == 'parameter_request_list' :
+            value = value.strip().split(',')
+            tmp = []
+            for each in value:
+                if DhcpOptions.has_key(each) : tmp.append(DhcpOptions[each])
+            return tmp
+        elif  p=='dhcp_message_type' :
+            try :
+                return [DhcpNames[value]]
+            except KeyError:
+                return
+
+        # 2- Search for options
+        try : option_type = DhcpOptionsTypes[DhcpOptions[parameter]]
+        except KeyError : return False
+
+        if option_type == "ipv4" :
+            # this is a single ip address
+            try :
+                binary_value = map(int,value.split("."))
+            except ValueError : return False
+            
+        elif option_type == "ipv4+" :
+            # this is multiple ip address
+            iplist = value.split(",")
+            opt = []
+            for single in iplist :
+                opt += (ipv4(single).list())
+            binary_value = opt
+
+        elif option_type == "32-bits" :
+            # This is probably a number...
+            try :
+                digit = int(value)
+                binary_value = [digit>>24&0xFF,(digit>>16)&0xFF,(digit>>8)&0xFF,digit&0xFF]
+            except ValueError :
+                return False
+
+        elif option_type == "16-bits" :
+            try :
+                digit = int(value)
+                binary_value = [(digit>>8)&0xFF,digit&0xFF]
+            except ValueError : return False
+
+
+        elif option_type == "char" :
+            try :
+                digit = int(value)
+                binary_value = [digit&0xFF]
+            except ValueError : return False
+
+        elif option_type == "bool" :
+            if value=="False" or value=="false" or value==0 :
+                binary_value = [0]
+            else : binary_value = [1]
+            
+        elif option_type == "string" :
+            binary_value = strlist(value).list()
+
+        else :
+            binary_value = strlist(value).list()
+        
+        return binary_value
+    
+    # FIXME: This is called from IsDhcpSomethingPacket, but is this really
+    # needed?  Or maybe this testing should be done in
+    # DhcpBasicPacket.DecodePacket().
+
+    # Test Packet Type
+    def IsDhcpSomethingPacket(self,type):
+        if self.IsDhcpPacket() == False : return False
+        if self.IsOption("dhcp_message_type") == False : return False
+        if self.GetOption("dhcp_message_type") != type : return False
+        return True
+    
+    def IsDhcpDiscoverPacket(self):
+        return self.IsDhcpSomethingPacket([1])
+
+    def IsDhcpOfferPacket(self):
+        return self.IsDhcpSomethingPacket([2])
+
+    def IsDhcpRequestPacket(self):
+        return self.IsDhcpSomethingPacket([3])
+
+    def IsDhcpDeclinePacket(self):
+        return self.IsDhcpSomethingPacket([4])
+
+    def IsDhcpAckPacket(self):
+        return self.IsDhcpSomethingPacket([5])
+
+    def IsDhcpNackPacket(self):
+        return self.IsDhcpSomethingPacket([6])
+
+    def IsDhcpReleasePacket(self):
+        return self.IsDhcpSomethingPacket([7])
+
+    def IsDhcpInformPacket(self):
+        return self.IsDhcpSomethingPacket([8])
+
+
+    def GetMultipleOptions(self,options=()):
+        result = {}
+        for each in options:
+            result[each] = self.GetOption(each)
+        return result
+
+    def SetMultipleOptions(self,options={}):
+        for each in options.keys():
+            self.SetOption(each,options[each])
+
+
+
+
+
+
+    # Creating Response Packet
+
+    # Server-side functions
+    # From RFC 2132 page 28/29
+    def CreateDhcpOfferPacketFrom(self,src): # src = discover packet
+        self.SetOption("htype",src.GetOption("htype"))
+        self.SetOption("xid",src.GetOption("xid"))
+        self.SetOption("flags",src.GetOption("flags"))
+        self.SetOption("giaddr",src.GetOption("giaddr"))
+        self.SetOption("chaddr",src.GetOption("chaddr"))
+        self.SetOption("ip_address_lease_time",src.GetOption("ip_address_lease_time"))
+        self.TransformToDhcpOfferPacket()
+
+    def TransformToDhcpOfferPacket(self):
+        self.SetOption("dhcp_message_type",[2])
+        self.SetOption("op",[2])
+        self.SetOption("hlen",[6]) 
+
+        self.DeleteOption("secs")
+        self.DeleteOption("ciaddr")
+        self.DeleteOption("request_ip_address")
+        self.DeleteOption("parameter_request_list")
+        self.DeleteOption("client_identifier")
+        self.DeleteOption("maximum_message_size")
+
+
+
+
+
+    """ Dhcp ACK packet creation """
+    def CreateDhcpAckPacketFrom(self,src): # src = request or inform packet
+        self.SetOption("htype",src.GetOption("htype"))
+        self.SetOption("xid",src.GetOption("xid"))
+        self.SetOption("ciaddr",src.GetOption("ciaddr"))
+        self.SetOption("flags",src.GetOption("flags"))
+        self.SetOption("giaddr",src.GetOption("giaddr"))
+        self.SetOption("chaddr",src.GetOption("chaddr"))
+        self.SetOption("ip_address_lease_time_option",src.GetOption("ip_address_lease_time_option"))
+        self.TransformToDhcpAckPacket()
+
+    def TransformToDhcpAckPacket(self): # src = request or inform packet
+        self.SetOption("op",[2])
+        self.SetOption("hlen",[6]) 
+        self.SetOption("dhcp_message_type",[5])
+
+        self.DeleteOption("secs")
+        self.DeleteOption("request_ip_address")
+        self.DeleteOption("parameter_request_list")
+        self.DeleteOption("client_identifier")
+        self.DeleteOption("maximum_message_size")
+
+
+    """ Dhcp NACK packet creation """
+    def CreateDhcpNackPacketFrom(self,src): # src = request or inform packet
+        
+        self.SetOption("htype",src.GetOption("htype"))
+        self.SetOption("xid",src.GetOption("xid"))
+        self.SetOption("flags",src.GetOption("flags"))
+        self.SetOption("giaddr",src.GetOption("giaddr"))
+        self.SetOption("chaddr",src.GetOption("chaddr"))
+        self.TransformToDhcpNackPacket()
+
+    def TransformToDhcpNackPacket(self):
+        self.SetOption("op",[2])
+        self.SetOption("hlen",[6]) 
+        self.DeleteOption("secs")
+        self.DeleteOption("ciaddr")
+        self.DeleteOption("yiaddr")
+        self.DeleteOption("siaddr")
+        self.DeleteOption("sname")
+        self.DeleteOption("file")
+        self.DeleteOption("request_ip_address")
+        self.DeleteOption("ip_address_lease_time_option")
+        self.DeleteOption("parameter_request_list")
+        self.DeleteOption("client_identifier")
+        self.DeleteOption("maximum_message_size")
+        self.SetOption("dhcp_message_type",[6])
+
+
+
+
+
+
+
+    """ GetClientIdentifier """
+
+    def GetClientIdentifier(self) :
+        if self.IsOption("client_identifier") :
+            return self.GetOption("client_identifier")
+        return []
+
+    def GetGiaddr(self) :
+        return self.GetOption("giaddr")
+
+    def GetHardwareAddress(self) :
+        length = self.GetOption("hlen")[0]
+        full_hw = self.GetOption("chaddr")
+        if length!=[] and length<len(full_hw) : return full_hw[0:length]
+        return full_hw
+

type_hwmac.py

@@ -0,0 +1,85 @@
+# pydhcplib
+# Copyright (C) 2008 Mathieu Ignacio -- mignacio@april.org
+#
+# This file is part of pydhcplib.
+# Pydhcplib 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 3 of the License, or
+# (at your option) any later version.
+#
+# This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
+
+
+from binascii import unhexlify,hexlify
+
+# Check and convert hardware/nic/mac address type
+class hwmac:
+    def __init__(self,value="00:00:00:00:00:00") :
+        self._hw_numlist = []
+        self._hw_string = ""
+        hw_type = type(value)
+        if hw_type == str :
+            value = value.strip()
+            self._hw_string = value
+            self._StringToNumlist(value)
+            self._CheckNumList()
+        elif hw_type == list :
+            self._hw_numlist = value
+            self._CheckNumList()
+            self._NumlistToString()
+        else : raise TypeError , 'hwmac init : Valid types are str and list'
+
+
+
+    # Check if _hw_numlist is valid and raise error if not.
+    def _CheckNumList(self) :
+        if len(self._hw_numlist) != 6 : raise ValueError , "hwmac : wrong list length."
+        for part in self._hw_numlist :
+            if type (part) != int : raise TypeError , "hwmac : each element of list must be int"
+            if part < 0 or part > 255 : raise ValueError , "hwmac : need numbers between 0 and 255."
+        return True
+
+
+    def _StringToNumlist(self,value):
+        self._hw_string = self._hw_string.replace("-",":").replace(".",":")
+        self._hw_string = self._hw_string.lower()
+
+        for twochar in self._hw_string.split(":"):
+            self._hw_numlist.append(ord(unhexlify(twochar)))
+            
+    # Convert NumList type ip to String type ip
+    def _NumlistToString(self) :
+        self._hw_string = ":".join(map(hexlify,map(chr,self._hw_numlist)))
+
+    # Convert String type ip to NumList type ip
+    # return ip string
+    def str(self) :
+        return self._hw_string
+
+    # return ip list (useful for DhcpPacket class)
+    def list(self) :
+        return self._hw_numlist+[0]*10
+
+    def __hash__(self) :
+        return self._hw_string.__hash__()
+
+    def __repr__(self) :
+        return self._hw_string
+
+    def __cmp__(self,other) :
+        if self._hw_string == other : return 0
+        return 1
+
+    def __nonzero__(self) :
+        if self._hw_string != "00:00:00:00:00:00" : return 1
+        return 0
+
+
+
+

type_ipv4.py

@@ -0,0 +1,112 @@
+# pydhcplib
+# Copyright (C) 2008 Mathieu Ignacio -- mignacio@april.org
+#
+# This file is part of pydhcplib.
+# Pydhcplib 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 3 of the License, or
+# (at your option) any later version.
+#
+# This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
+
+
+# Check and convert ipv4 address type
+class ipv4:
+    def __init__(self,value="0.0.0.0") :
+        ip_type = type(value)
+        if ip_type == str :
+            if not self.CheckString(value) : raise ValueError, "ipv4 string argument is not an valid ip "
+            self._ip_string = value
+            self._StringToNumlist()
+            self._StringToLong()
+            self._NumlistToString()
+        elif ip_type == list :
+            if not self.CheckNumList(value) : raise ValueError, "ipv4 list argument is not an valid ip "
+            self._ip_numlist = value
+            self._NumlistToString()
+            self._StringToLong()
+        elif ip_type == int or ip_type == long:
+            self._ip_long = value
+            self._LongToNumlist()
+            self._NumlistToString()
+        elif ip_type == bool :
+            self._ip_long = 0
+            self._LongToNumlist()
+            self._NumlistToString()
+            
+        else : raise TypeError , 'ipv4 init : Valid types are str, list, int or long'
+
+    # Convert Long type ip to numlist ip
+    def _LongToNumlist(self) :
+        self._ip_numlist = [self._ip_long >> 24 & 0xFF]
+        self._ip_numlist.append(self._ip_long >> 16 & 0xFF)
+        self._ip_numlist.append(self._ip_long >> 8 & 0xFF)
+        self._ip_numlist.append(self._ip_long & 0xFF)
+        if not self.CheckNumList(self._ip_numlist) : raise ValueError, "ipv4 list argument is not an valid ip "
+    # Convert String type ip to Long type ip
+    def _StringToLong(self) :
+        ip_numlist = map(int,self._ip_string.split('.'))
+        self._ip_long = ip_numlist[3] + ip_numlist[2]*256 + ip_numlist[1]*256*256 + ip_numlist[0]*256*256*256
+        if not self.CheckNumList(self._ip_numlist) : raise ValueError, "ipv4 list argument is not an valid ip "
+    # Convert NumList type ip to String type ip
+    def _NumlistToString(self) :
+        self._ip_string = ".".join(map(str,self._ip_numlist))
+        if not self.CheckNumList(self._ip_numlist) : raise ValueError, "ipv4 list argument is not an valid ip "
+    # Convert String type ip to NumList type ip
+    def _StringToNumlist(self) :
+        self._ip_numlist = map(int,self._ip_string.split('.'))
+        if not self.CheckNumList(self._ip_numlist) : raise ValueError, "ipv4 list argument is not an valid ip "
+
+    """ Public methods """
+    # Check if _ip_numlist is valid and raise error if not.
+    # self._ip_numlist
+    def CheckNumList(self,value) :
+        if len(value) != 4 : return False
+        for part in value :
+            if part < 0 or part > 255 : return False
+        return True
+
+    # Check if _ip_numlist is valid and raise error if not.
+    def CheckString(self,value) :
+        tmp = value.strip().split('.')
+        if len(tmp) != 4 :  return False
+        for each in tmp : 
+            if not each.isdigit() : return False
+        return True
+    
+    # return ip string
+    def str(self) :
+        return self._ip_string
+
+    # return ip list (useful for DhcpPacket class)
+    def list(self) :
+        return self._ip_numlist
+
+    # return Long ip type (useful for SQL ip address backend)
+    def int(self) :
+        return self._ip_long
+
+
+    """ Useful function for native python operations """
+
+    def __hash__(self) :
+        return self._ip_long.__hash__()
+
+    def __repr__(self) :
+        return self._ip_string
+
+    def __cmp__(self,other) :
+        return cmp(self._ip_long, other._ip_long);
+
+    def __nonzero__(self) :
+        if self._ip_long != 0 : return 1
+        return 0
+
+
+

type_strlist.py

@@ -0,0 +1,65 @@
+# pydhcplib
+# Copyright (C) 2008 Mathieu Ignacio -- mignacio@april.org
+#
+# This file is part of pydhcplib.
+# Pydhcplib 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 3 of the License, or
+# (at your option) any later version.
+#
+# This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
+
+class strlist :
+    def __init__(self,data="") :
+        str_type = type(data)
+        self._str = ""
+        self._list = []
+        
+        if str_type == str :
+            self._str = data
+            for each in range(len(self._str)) :
+                self._list.append(ord(self._str[each]))
+        elif str_type == list :
+            self._list = data
+            self._str = "".join(map(chr,self._list))
+        else : raise TypeError , 'strlist init : Valid types are str and  list of int'
+
+    # return string
+    def str(self) :
+        return self._str
+
+    # return list (useful for DhcpPacket class)
+    def list(self) :
+        return self._list
+
+    # return int
+    # FIXME
+    def int(self) :
+        return 0
+
+
+
+    """ Useful function for native python operations """
+
+    def __hash__(self) :
+        return self._str.__hash__()
+
+    def __repr__(self) :
+        return self._str
+
+    def __nonzero__(self) :
+        if self._str != "" : return 1
+        return 0
+
+    def __cmp__(self,other) :
+        if self._str == other : return 0
+        return 1
+		    
+
+