1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
|
# $Id: tftp.py 23 2006-11-08 15:45:33Z dugsong $
# -*- coding: utf-8 -*-
"""Trivial File Transfer Protocol."""
from __future__ import print_function
from __future__ import absolute_import
import struct
from . import dpkt
# Opcodes
OP_RRQ = 1 # read request
OP_WRQ = 2 # write request
OP_DATA = 3 # data packet
OP_ACK = 4 # acknowledgment
OP_ERR = 5 # error code
# Error codes
EUNDEF = 0 # not defined
ENOTFOUND = 1 # file not found
EACCESS = 2 # access violation
ENOSPACE = 3 # disk full or allocation exceeded
EBADOP = 4 # illegal TFTP operation
EBADID = 5 # unknown transfer ID
EEXISTS = 6 # file already exists
ENOUSER = 7 # no such user
class TFTP(dpkt.Packet):
"""Trivial File Transfer Protocol.
TODO: Longer class information....
Attributes:
__hdr__: Header fields of TFTP.
TODO.
"""
__hdr__ = (('opcode', 'H', 1), )
def unpack(self, buf):
dpkt.Packet.unpack(self, buf)
if self.opcode in (OP_RRQ, OP_WRQ):
l = self.data.split(b'\x00')
self.filename = l[0]
self.mode = l[1]
self.data = b''
elif self.opcode in (OP_DATA, OP_ACK):
self.block = struct.unpack('>H', self.data[:2])[0]
self.data = self.data[2:]
elif self.opcode == OP_ERR:
self.errcode = struct.unpack('>H', self.data[:2])
self.errmsg = self.data[2:].split(b'\x00')[0]
self.data = b''
def __len__(self):
return len(bytes(self))
def __bytes__(self):
if self.opcode in (OP_RRQ, OP_WRQ):
s = self.filename + b'\x00' + self.mode + b'\x00'
elif self.opcode in (OP_DATA, OP_ACK):
s = struct.pack('>H', self.block)
elif self.opcode == OP_ERR:
s = struct.pack('>H', self.errcode) + (b'%s\x00' % self.errmsg)
else:
s = b''
return self.pack_hdr() + s + self.data
def test_op_rrq():
s = b'\x00\x01\x72\x66\x63\x31\x33\x35\x30\x2e\x74\x78\x74\x00\x6f\x63\x74\x65\x74\x00'
t = TFTP(s)
assert t.filename == b'rfc1350.txt'
assert t.mode == b'octet'
assert bytes(t) == s
def test_op_data():
s = b'\x00\x03\x00\x01\x0a\x0a\x4e\x65\x74\x77\x6f\x72\x6b\x20\x57\x6f\x72\x6b\x69\x6e\x67\x20\x47\x72\x6f\x75\x70'
t = TFTP(s)
assert t.block == 1
assert t.data == b'\x0a\x0aNetwork Working Group'
assert bytes(t) == s
def test_op_err():
pass # XXX - TODO
if __name__ == '__main__':
test_op_rrq()
test_op_data()
test_op_err()
print('Tests Successful...')
|
