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pycrate/pycrate_ether/IP.py

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# −*− coding: UTF−8 −*−
#/**
# * Software Name : pycrate
# * Version : 0.3
# *
# * Copyright 2016. Benoit Michau. ANSSI.
# *
# * This library is free software; you can redistribute it and/or
# * modify it under the terms of the GNU Lesser General Public
# * License as published by the Free Software Foundation; either
# * version 2.1 of the License, or (at your option) any later version.
# *
# * This library 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
# * Lesser General Public License for more details.
# *
# * You should have received a copy of the GNU Lesser General Public
# * License along with this library; if not, write to the Free Software
# * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
# * MA 02110-1301 USA
# *
# *--------------------------------------------------------
# * File Name : pycrate_ether/IP.py
# * Created : 2016-04-27
# * Authors : Benoit Michau
# *--------------------------------------------------------
#*/
from socket import inet_aton, inet_ntoa, AF_INET, AF_INET6
from struct import pack
from array import array
try:
from socket import inet_pton, inet_ntop
except ImportError:
try:
from win_inet_pton import inet_pton, inet_ntop
except ImportError:
print('[pycrate_ether/IP.py] inet_pton() and inet_ntop() not available')
from pycrate_core.utils import reverse_dict
from pycrate_core.elt import Envelope, Array, REPR_RAW, REPR_HEX, REPR_BIN
from pycrate_core.base import *
from pycrate_core.repr import *
#------------------------------------------------------------------------------#
# code borrowed from scapy:
# see scapy code at https://github.com/secdev/scapy/blob/master/scapy/utils.py
# see http://www.secdev.org/projects/scapy for more informations
# Copyright (C) Philippe Biondi <phil@secdev.org>
# This program is published under a GPLv2 license
if pack('H', 1) == b'\0\x01': # big endian
def checksum(pkt):
if len(pkt) % 2 == 1:
pkt += b'\0'
s = sum(array('H', pkt))
s = (s >> 16) + (s & 0xffff)
s += s >> 16
s = ~s
return s & 0xffff
else:
def checksum(pkt):
if len(pkt) % 2 == 1:
pkt += b'\0'
s = sum(array('H', pkt))
s = (s >> 16) + (s & 0xffff)
s += s >> 16
s = ~s
return (((s>>8)&0xff)|s<<8) & 0xffff
# End-Of-Scapy
#------------------------------------------------------------------------------#
IPProt_dict = {
0 : 'HOPOPT',
1 : 'ICMP',
2 : 'IGMP',
3 : 'GGP',
4 : 'IP',
5 : 'ST',
6 : 'TCP',
7 : 'CBT',
8 : 'EGP',
9 : 'IGP',
10 : 'BBN-RCC-MON',
11 : 'NVP-II',
12 : 'PUP',
13 : 'ARGUS',
14 : 'EMCON',
15 : 'XNET',
16 : 'CHAOS',
17 : 'UDP',
18 : 'MUX',
19 : 'DCN-MEAS',
20 : 'HMP',
21 : 'PRM',
22 : 'XNS-IDP',
23 : 'TRUNK-1',
24 : 'TRUNK-2',
25 : 'LEAF-1',
26 : 'LEAF-2',
27 : 'RDP',
28 : 'IRTP',
29 : 'ISO-TP4',
30 : 'NETBLT',
31 : 'MFE-NSP',
32 : 'MERIT-INP',
33 : 'DCCP',
34 : '3PC',
35 : 'IDPR',
36 : 'XTP',
37 : 'DDP',
38 : 'IDPR-CMTP',
39 : 'TP++',
40 : 'IL',
41 : 'IPv6',
42 : 'SDRP',
43 : 'IPv6-Route',
44 : 'IPv6-Frag',
45 : 'IDRP',
46 : 'RSVP',
47 : 'GRE',
48 : 'DSR',
49 : 'BNA',
50 : 'ESP',
51 : 'AH',
52 : 'I-NLSP',
53 : 'SWIPE',
54 : 'NARP',
55 : 'MOBILE',
56 : 'TLSP',
57 : 'SKIP',
58 : 'IPv6-ICMP',
59 : 'IPv6-NoNxt',
60 : 'IPv6-Opts',
61 : 'any',
62 : 'CFTP',
63 : 'any',
64 : 'SAT-EXPAK',
65 : 'KRYPTOLAN',
66 : 'RVD',
67 : 'IPPC',
68 : 'any',
69 : 'SAT-MON',
70 : 'VISA',
71 : 'IPCV',
72 : 'CPNX',
73 : 'CPHB',
74 : 'WSN',
75 : 'PVP',
76 : 'BR-SAT-MON',
77 : 'SUN-ND',
78 : 'WB-MON',
79 : 'WB-EXPAK',
80 : 'ISO-IP',
81 : 'VMTP',
82 : 'SECURE-VMTP',
83 : 'VINES',
84 : 'TTP',
85 : 'NSFNET-IGP',
86 : 'DGP',
87 : 'TCF',
88 : 'EIGRP',
89 : 'OSPFIGP',
90 : 'Sprite-RPC',
91 : 'LARP',
92 : 'MTP',
93 : 'AX.25',
94 : 'IPIP',
95 : 'MICP',
96 : 'SCC-SP',
97 : 'ETHERIP',
98 : 'ENCAP',
99 : 'any',
100 : 'GMTP',
101 : 'IFMP',
102 : 'PNNI',
103 : 'PIM',
104 : 'ARIS',
105 : 'SCPS',
106 : 'QNX',
107 : 'A/N',
108 : 'IPComp',
109 : 'SNP',
110 : 'Compaq-Peer',
111 : 'IPX-in-IP',
112 : 'VRRP',
113 : 'PGM',
114 : 'any',
115 : 'L2TP',
116 : 'DDX',
117 : 'IATP',
118 : 'STP',
119 : 'SRP',
120 : 'UTI',
121 : 'SMP',
122 : 'SM',
123 : 'PTP',
124 : 'ISIS',
125 : 'FIRE',
126 : 'CRTP',
127 : 'CRUDP',
128 : 'SSCOPMCE',
129 : 'IPLT',
130 : 'SPS',
131 : 'PIPE',
132 : 'SCTP',
133 : 'FC',
134 : 'RSVP-E2E-IGNORE',
135 : 'Mobility',
136 : 'UDPLite',
137 : 'MPLS-in-IP',
138 : 'manet',
139 : 'HIP',
140 : 'Shim6',
253 : 'Experimentation',
254 : 'Experimentation',
255 : 'Reserved'
}
IPProtRev_dict = reverse_dict(IPProt_dict)
IPv4Opt_dict = {
0: 'EndofOptions',
1: 'NoOperation',
7: 'RecordRoute',
10: 'ExperimentalMeasurement',
11: 'MTUProbe',
12: 'MTUReply',
15: 'ENCODE',
25: 'Quick-Start',
30: 'RFC3692-styleExperiment',
68: 'TimeStamp',
82: 'Traceroute',
94: 'RFC3692-styleExperiment',
130: 'Security',
131: 'LooseSourceRoute',
133: 'ExtendedSecurity',
134: 'CommercialSecurity',
136: 'StreamID',
137: 'StrictSourceRoute',
142: 'ExpermentalAccessControl',
144: 'IMITrafficDescriptor',
145: 'ExtendedInternetProtocol',
147: 'AddressExtension',
148: 'RouterAlert',
149: 'SelectiveDirectedBroadcast',
151: 'DynamicPacketState',
152: 'UpstreamMulticastPkt',
158: 'RFC3692-styleExperiment',
205: 'ExperimentalFlowControl',
222: 'RFC3692-styleExperiment',
}
IPv4Preced_dict = {
0 : 'Routine',
1 : 'Priority',
2 : 'Immediate',
3 : 'Flash',
4 : 'Flash Override',
5 : 'CRITIC/ECP',
6 : 'Internetwork Control',
7 : 'Network Control'
}
class IPv4Option(Envelope):
_GEN = (
Uint8('CCN', dic=IPv4Opt_dict),
Uint8('len'), # trans and val automated
Buf('val', val=b'') # trans and bl automated
)
def __init__(self, *args, **kwargs):
Envelope.__init__(self, *args, **kwargs)
self[1].set_transauto(self._set_trans)
self[1].set_valauto(self._set_len_val)
self[2].set_transauto(self._set_trans)
self[2].set_blauto(self._set_val_bl)
def _set_trans(self):
if self[0].get_val() in (0, 1):
return True
else:
return False
def _set_len_val(self):
return 2 + self[2].get_len()
def _set_val_bl(self):
return max(0, 8 * (self[1].get_val()-2))
class IPv4Options(Envelope):
_GEN = (
Array('opts', GEN=IPv4Option()),
Buf('pad') # bl automated
)
def __init__(self, *args, **kwargs):
Envelope.__init__(self, *args, **kwargs)
self[1].set_blauto(self._set_pad_bl)
def _set_pad_bl(self):
opts_ext = self[0].get_bl() % 32
if opts_ext:
return 32 - opts_ext
else:
return 0
class IPv4(Envelope):
_GEN = (
Uint('vers', val=4, bl=4),
Uint('hdr_wlen', bl=4), # val automated
Uint('precedence', bl=3, dic=IPv4Preced_dict),
Uint('delay', bl=1, dic={0:'Normal', 1:'Low'}),
Uint('throughput', bl=1, dic={0:'Normal', 1:'High'}),
Uint('reliab', bl=1, dic={0:'Normal', 1:'High'}),
Uint('res_1', bl=2, rep=REPR_BIN),
Uint16('len'), # val automated, unless initialized to fixed value
Uint16('id'),
Uint('res_2', bl=1, rep=REPR_BIN),
Uint('DF', bl=1, dic={0:'may fragment', 1:'do not fragment'}),
Uint('MF', bl=1, dic={0:'last fragment', 1:'more fragment'}),
Uint('frag_off', bl=13),
Uint8('TTL', val=24),
Uint8('proto', dic=IPProt_dict), # val automated, unless initialized to fixed value
Uint16('hdr_cs', rep=REPR_HEX), # val automated
Buf('src', val=b'\x7f\0\0\x01', bl=32, rep=REPR_HEX),
Buf('dst', val=b'\x7f\0\0\x01', bl=32, rep=REPR_HEX),
Buf('opt', val=b''), # bl automated
)
def __init__(self, *args, **kwargs):
# enable to pass IPv4 addr in human-readable format
if 'val' in kwargs:
if 'src' in kwargs['val'] and len(kwargs['val']['src']) > 4:
try:
kwargs['val']['src'] = inet_aton(kwargs['val']['src'])
except:
pass
if 'dst' in kwargs['val'] and len(kwargs['val']['dst']) > 4:
try:
kwargs['val']['dst'] = inet_aton(kwargs['val']['dst'])
except:
pass
Envelope.__init__(self, *args, **kwargs)
self[1].set_valauto(self._set_hdrwlen_val)
if 'val' not in kwargs or 'len' not in kwargs['val']:
self[7].set_valauto(self._set_len_val)
if 'val' not in kwargs or 'proto' not in kwargs['val']:
self[14].set_valauto(self._set_prot_val)
self[15].set_valauto(self.checksum)
self[18].set_blauto(self._set_opt_bl)
def _set_hdrwlen_val(self):
return 5 + (self[18].get_len() // 4)
def _set_len_val(self):
pay = self.get_payload()
if pay is not None:
return 20 + self[18].get_len() + pay.get_len()
else:
return 20 + self[18].get_len()
def _set_prot_val(self):
pay = self.get_payload()
if pay is not None and pay[0]._name in IPProtRev_dict:
return IPProtRev_dict[pay[0]._name]
else:
return 0xff
def checksum(self):
return checksum(self[:15].to_bytes() + b'\0\0' + self[16:].to_bytes())
def _set_opt_bl(self):
return max(0, 32 * (self[1].get_val()-5))
def _from_char(self, char):
Envelope._from_char(self, char)
opts_buf = self[18].get_val()
if opts_buf:
opts = IPv4Options()
opts.from_bytes(opts_buf)
if opts.to_bytes() == opts_buf:
self.replace(self[18], opts)
class ICMP(Envelope):
_GEN = (
Uint8('type', val=8),
Uint8('code'),
Uint16('cs', rep=REPR_HEX), # val automated
Buf('data', val=b'\0\0coucou')
)
def __init__(self, *args, **kwargs):
Envelope.__init__(self, *args, **kwargs)
self[2].set_valauto(self.checksum)
def checksum(self):
cs_old = self[2]._val
self[2]._val = 0
icmp = self.to_bytes()
self[2]._val = cs_old
return checksum(icmp)
class IPv6(Envelope):
_GEN = (
Uint('vers', val=6, bl=4),
Uint8('class'),
Uint('flow', bl=20, rep=REPR_HEX),
Uint16('plen'), # val automated, unless initialized to fixed value
Uint8('next', dic=IPProt_dict), # val automated, unless initialized to fixed value
Uint8('hop_limit', val=24),
Buf('src', val=15*b'\0'+b'\x01', bl=128, rep=REPR_HEX),
Buf('dst', val=15*b'\0'+b'\x01', bl=128, rep=REPR_HEX)
)
def __init__(self, *args, **kwargs):
# enable to pass IPv4 addr in human-readable format
if 'val' in kwargs:
if 'src' in kwargs['val'] and len(kwargs['val']['src']) != 16:
try:
kwargs['val']['src'] = inet_pton(AF_INET6, kwargs['val']['src'])
except:
pass
if 'dst' in kwargs['val'] and len(kwargs['val']['dst']) != 16:
try:
kwargs['val']['dst'] = inet_pton(AF_INET6, kwargs['val']['dst'])
except:
pass
Envelope.__init__(self, *args, **kwargs)
if 'val' not in kwargs or 'plen' not in kwargs['val']:
self[3].set_valauto(self._set_plen_val)
if 'val' not in kwargs or 'next' not in kwargs['val']:
self[4].set_valauto(self._set_next_val)
def _set_plen_val(self):
pay = self.get_payload()
if pay is not None:
return pay.get_len()
else:
return 0
def _set_next_val(self):
pay = self.get_payload()
if pay is not None and pay[0]._name in IPProtRev_dict:
return IPProtRev_dict[pay[0]._name]
else:
return 0xff
class UDP(Envelope):
_CS_OFF = False # for checksum offload
_GEN = (
Uint16('src'),
Uint16('dst'),
Uint16('len'), # val automated, unless initialized to fixed value
Uint16('cs', rep=REPR_HEX) # val automated
)
def __init__(self, *args, **kwargs):
Envelope.__init__(self, *args, **kwargs)
if 'val' not in kwargs or 'len' not in kwargs['val']:
self[2].set_valauto(self._set_len_val)
self[3].set_valauto(self.checksum)
def _set_len_val(self):
pay = self.get_payload()
if pay is not None:
return 8 + pay.get_len()
else:
return 8
def checksum(self):
if self._CS_OFF:
return 0
# get UDP and payload buffer
pay = self.get_payload()
if pay is not None:
udp = b''.join((self[:3].to_bytes(),
b'\0\0',
pay.to_bytes()))
else:
udp = self[:3].to_bytes() + b'\0\0'
# get pseudo hdr buffer
ludp = len(udp)
hdr = self.get_header()
if hdr is not None:
# keep only src addr, dst addr and prot
vers = hdr[0].get_val()
if vers == 4:
phdr = b''.join((hdr[16].to_bytes(),
hdr[17].to_bytes(),
b'\0\x11',
pack('>H', ludp)))
elif vers == 6:
# WNG: in case of IPv6 routing header, dst addr is incorrect
phdr = b''.join((hdr[6].to_bytes(),
hdr[7].to_bytes(),
b'\0\x11',
pack('>H', ludp)))
else:
phdr = b''
else:
phdr = b''
# compute checksum
return checksum(b''.join((phdr, udp)))
class TCP(Envelope):
_CS_OFF = False # for checksum offload
_GEN = (
Uint16('src'),
Uint16('dst'),
Uint32('seq'),
Uint32('ack'),
Uint('off', bl=4), # val automated, unless initialized to fixed value
Uint('res', bl=3, rep=REPR_BIN),
Uint('NS', bl=1),
Uint('CWR', bl=1),
Uint('ECE', bl=1),
Uint('URG', bl=1),
Uint('ACK', bl=1),
Uint('PSH', bl=1),
Uint('RST', bl=1),
Uint('SYN', bl=1),
Uint('FIN', bl=1),
Uint16('win', val=8192),
Uint16('cs', rep=REPR_HEX), # val automated
Uint16('urg'),
Buf('opt', val=b'') # bl automated
)
def __init__(self, *args, **kwargs):
Envelope.__init__(self, *args, **kwargs)
if 'val' not in kwargs or 'off' not in kwargs['val']:
self[4].set_valauto(self._set_off_val)
self[16].set_valauto(self.checksum)
self[18].set_blauto(self._set_opt_bl)
def _set_off_val(self):
return 5 + (self[18].get_len() // 4)
def checksum(self):
if self._CS_OFF:
return 0
# get TCP and payload buffer
pay = self.get_payload()
if pay is not None:
tcp = b''.join((self[:16].to_bytes(),
b'\0\0',
self[17:].to_bytes(),
pay.to_bytes()))
else:
tcp = b''.join((self[:16].to_bytes(),
b'\0\0',
self[17:].to_bytes()))
# get pseudo hdr buffer
ltcp = len(tcp)
hdr = self.get_header()
if hdr is not None:
# keep only src addr, dst addr and prot
vers = hdr[0].get_val()
if vers == 4:
phdr = b''.join((hdr[16].to_bytes(),
hdr[17].to_bytes(),
b'\0\x06',
pack('>H', ltcp)))
elif vers == 6:
# WNG: in case of IPv6 routing header, dst addr is incorrect
phdr = b''.join((hdr[6].to_bytes(),
hdr[7].to_bytes(),
b'\0\x06',
pack('>H', ltcp)))
else:
phdr = b''
else:
phdr = b''
# compute checksum
return checksum(phdr + tcp)
def _set_opt_bl(self):
return max(0, 32 * (self[4].get_val()-5))
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