Source Code for Module dpkt.snoop

  1  # $Id$ 
  2  # -*- coding: utf-8 -*- 
  3  """Snoop file format.""" 
  4  from __future__ import absolute_import 
  5   
  6  import time 
  7   
  8  from . import dpkt 
  9   
 10  # RFC 1761 
 11   
 12  SNOOP_MAGIC = 0x736E6F6F70000000 
 13   
 14  SNOOP_VERSION = 2 
 15   
 16  SDL_8023 = 0 
 17  SDL_8024 = 1 
 18  SDL_8025 = 2 
 19  SDL_8026 = 3 
 20  SDL_ETHER = 4 
 21  SDL_HDLC = 5 
 22  SDL_CHSYNC = 6 
 23  SDL_IBMCC = 7 
 24  SDL_FDDI = 8 
 25  SDL_OTHER = 9 
 26   
 27  dltoff = {SDL_ETHER: 14} 
 28   
 29   
 30 -class PktHdr(dpkt.Packet): 
 31      """snoop packet header. 
 32   
 33      TODO: Longer class information.... 
 34   
 35      Attributes: 
 36          __hdr__: Header fields of snoop packet header. 
 37          TODO. 
 38      """ 
 39   
 40      __byte_order__ = '!' 
 41      __hdr__ = ( 
 42          ('orig_len', 'I', 0), 
 43          ('incl_len', 'I', 0), 
 44          ('rec_len', 'I', 0), 
 45          ('cum_drops', 'I', 0), 
 46          ('ts_sec', 'I', 0), 
 47          ('ts_usec', 'I', 0), 
 48      ) 
 49   
 50   
 51 -class FileHdr(dpkt.Packet): 
 52      """snoop file header. 
 53   
 54      TODO: Longer class information.... 
 55   
 56      Attributes: 
 57          __hdr__: Header fields of snoop file header. 
 58          TODO. 
 59      """ 
 60   
 61      __byte_order__ = '!' 
 62      __hdr__ = ( 
 63          ('magic', 'Q', SNOOP_MAGIC), 
 64          ('v', 'I', SNOOP_VERSION), 
 65          ('linktype', 'I', SDL_ETHER), 
 66      ) 
 67   
 68   
 69 -class Writer(object): 
 70      """Simple snoop dumpfile writer. 
 71   
 72      TODO: Longer class information.... 
 73   
 74      Attributes: 
 75          TODO. 
 76      """ 
 77   
 78 -    def __init__(self, fileobj, linktype=SDL_ETHER): 
 79          self.__f = fileobj 
 80          fh = FileHdr(linktype=linktype) 
 81          self.__f.write(str(fh)) 
 82   
 83 -    def writepkt(self, pkt, ts=None): 
 84          if ts is None: 
 85              ts = time.time() 
 86          s = str(pkt) 
 87          n = len(s) 
 88          pad_len = 4 - n % 4 if n % 4 else 0 
 89          ph = PktHdr(orig_len=n, incl_len=n, 
 90                      rec_len=PktHdr.__hdr_len__ + n + pad_len, 
 91                      ts_sec=int(ts), 
 92                      ts_usec=int((int(ts) - float(ts)) * 1000000.0)) 
 93          self.__f.write(str(ph)) 
 94          self.__f.write(s + '\0' * pad_len) 
 95   
 96 -    def close(self): 
 97          self.__f.close() 
 98   
 99   
100 -class Reader(object): 
101      """Simple pypcap-compatible snoop file reader. 
102   
103      TODO: Longer class information.... 
104   
105      Attributes: 
106          TODO. 
107      """ 
108   
109 -    def __init__(self, fileobj): 
110          self.name = fileobj.name 
111          self.fd = fileobj.fileno() 
112          self.__f = fileobj 
113          buf = self.__f.read(FileHdr.__hdr_len__) 
114          self.__fh = FileHdr(buf) 
115          self.__ph = PktHdr 
116          if self.__fh.magic != SNOOP_MAGIC: 
117              raise ValueError('invalid snoop header') 
118          self.dloff = dltoff[self.__fh.linktype] 
119          self.filter = '' 
120   
121 -    def fileno(self): 
122          return self.fd 
123   
124 -    def datalink(self): 
125          return self.__fh.linktype 
126   
127 -    def setfilter(self, value, optimize=1): 
128          return NotImplementedError 
129   
130 -    def readpkts(self): 
131          return list(self) 
132   
133 -    def dispatch(self, cnt, callback, *args): 
134          if cnt > 0: 
135              for i in range(cnt): 
136                  ts, pkt = next(self) 
137                  callback(ts, pkt, *args) 
138          else: 
139              for ts, pkt in self: 
140                  callback(ts, pkt, *args) 
141   
142 -    def loop(self, callback, *args): 
143          self.dispatch(0, callback, *args) 
144   
145 -    def __iter__(self): 
146          self.__f.seek(FileHdr.__hdr_len__) 
147          while 1: 
148              buf = self.__f.read(PktHdr.__hdr_len__) 
149              if not buf: break 
150              hdr = self.__ph(buf) 
151              buf = self.__f.read(hdr.rec_len - PktHdr.__hdr_len__) 
152              yield (hdr.ts_sec + (hdr.ts_usec / 1000000.0), buf[:hdr.incl_len]) 
153