Source Code for Module dpkt.tftp

 1  # $Id: tftp.py 271 2006-01-11 16:03:33Z dugsong $ 
 2   
 3  """Trivial File Transfer Protocol.""" 
 4   
 5  import struct 
 6  import dpkt 
 7   
 8  # Opcodes 
 9  OP_RRQ     = 1    # read request 
10  OP_WRQ     = 2    # write request 
11  OP_DATA    = 3    # data packet 
12  OP_ACK     = 4    # acknowledgment 
13  OP_ERR     = 5    # error code 
14   
15  # Error codes 
16  EUNDEF     = 0    # not defined 
17  ENOTFOUND  = 1    # file not found 
18  EACCESS    = 2    # access violation 
19  ENOSPACE   = 3    # disk full or allocation exceeded 
20  EBADOP     = 4    # illegal TFTP operation 
21  EBADID     = 5    # unknown transfer ID 
22  EEXISTS    = 6    # file already exists 
23  ENOUSER    = 7    # no such user 
24   
25 -class TFTP(dpkt.Packet): 
26      __hdr__ = (('opcode', 'H', 1), ) 
27       
28 -    def unpack(self, buf): 
29          dpkt.Packet.unpack(self, buf) 
30          if self.opcode in (OP_RRQ, OP_WRQ): 
31              l = self.data.split('\x00') 
32              self.filename = l[0] 
33              self.mode = l[1] 
34              self.data = '' 
35          elif self.opcode in (OP_DATA, OP_ACK): 
36              self.block = struct.unpack('>H', self.data[:2]) 
37              self.data = self.data[2:] 
38          elif self.opcode == OP_ERR: 
39              self.errcode = struct.unpack('>H', self.data[:2]) 
40              self.errmsg = self.data[2:].split('\x00')[0] 
41              self.data = '' 
42   
43 -    def __len__(self): 
44          return len(str(self)) 
45   
46 -    def __str__(self): 
47          if self.opcode in (OP_RRQ, OP_WRQ): 
48              s = '%s\x00%s\x00' % (self.filename, self.mode) 
49          elif self.opcode in (OP_DATA, OP_ACK): 
50              s = struct.pack('>H', self.block) 
51          elif self.opcode == OP_ERR: 
52              s = struct.pack('>H', self.errcode) + ('%s\x00' % self.errmsg) 
53          else: 
54              s = '' 
55          return self.pack_hdr() + s + self.data 
56