utilities/ovs-pcap.in

   1 #! @PYTHON@
   2 #
   3 # Copyright (c) 2010 Nicira Networks.
   4 #
   5 # Licensed under the Apache License, Version 2.0 (the "License");
   6 # you may not use this file except in compliance with the License.
   7 # You may obtain a copy of the License at:
   8 #
   9 #     http://www.apache.org/licenses/LICENSE-2.0
  10 #
  11 # Unless required by applicable law or agreed to in writing, software
  12 # distributed under the License is distributed on an "AS IS" BASIS,
  13 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14 # See the License for the specific language governing permissions and
  15 # limitations under the License.
  16
  17 import binascii
  18 import getopt
  19 import struct
  20 import sys
  21
  22 class PcapException(Exception):
  23     pass
  24
  25 class PcapReader(object):
  26     def __init__(self, file_name):
  27         self.file = open(file_name, "rb")
  28         header = self.file.read(24)
  29         if len(header) != 24:
  30             raise PcapException("end of file reading pcap header")
  31         magic, version, thiszone, sigfigs, snaplen, network = \
  32             struct.unpack(">6I", header)
  33         if magic == 0xa1b2c3d4:
  34             self.header_format = ">4I"
  35         elif magic == 0xd4c3b2a1:
  36             self.header_format = "<4I"
  37         else:
  38             raise PcapException("bad magic %u reading pcap file "
  39                         "(expected 0xa1b2c3d4 or 0xd4c3b2a1)" % magic)
  40
  41     def read(self):
  42         header = self.file.read(16)
  43         if len(header) == 0:
  44             return None
  45         elif len(header) != 16:
  46             raise PcapException("end of file within pcap record header")
  47
  48         ts_sec, ts_usec, incl_len, orig_len = struct.unpack(self.header_format,
  49                                                             header)
  50         packet = self.file.read(incl_len)
  51         if len(packet) != incl_len:
  52             raise PcapException("end of file reading pcap packet data")
  53         return packet
  54 argv0 = sys.argv[0]
  55
  56 def usage():
  57     print """\
  58 %(argv0)s: print pcap file packet data as hex
  59 usage: %(argv0)s FILE
  60 where FILE is a PCAP file.
  61
  62 The following options are also available:
  63   -h, --help                  display this help message
  64   -V, --version               display version information\
  65 """ % {'argv0': argv0}
  66     sys.exit(0)
  67
  68 if __name__ == "__main__":
  69     try:
  70         try:
  71             options, args = getopt.gnu_getopt(sys.argv[1:], 'hV',
  72                                               ['help', 'version'])
  73         except getopt.GetoptException, geo:
  74             sys.stderr.write("%s: %s\n" % (argv0, geo.msg))
  75             sys.exit(1)
  76
  77         for key, value in options:
  78             if key in ['-h', '--help']:
  79                 usage()
  80             elif key in ['-V', '--version']:
  81                 print "ovs-pcap (Open vSwitch) @VERSION@"
  82             else:
  83                 sys.exit(0)
  84
  85         if len(args) != 1:
  86             sys.stderr.write("%s: exactly 1 non-option argument required "
  87                              "(use --help for help)\n" % argv0)
  88             sys.exit(1)
  89
  90         reader = PcapReader(args[0])
  91         while True:
  92             packet = reader.read()
  93             if packet is None:
  94                 break
  95
  96             print binascii.hexlify(packet)
  97
  98     except PcapException, e:
  99         sys.stderr.write("%s: %s\n" % (argv0, e))
 100         sys.exit(1)
 101
 102 # Local variables:
 103 # mode: python
 104 # End: