3 # Copyright (c) 2010 Nicira, Inc.
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:
9 # http://www.apache.org/licenses/LICENSE-2.0
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.
22 class PcapException(Exception):
25 class PcapReader(object):
26 def __init__(self, file_name):
27 self.file = open(file_name, "rb")
28 header = self.file.read(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"
38 raise PcapException("bad magic %u reading pcap file "
39 "(expected 0xa1b2c3d4 or 0xd4c3b2a1)" % magic)
42 header = self.file.read(16)
45 elif len(header) != 16:
46 raise PcapException("end of file within pcap record header")
48 ts_sec, ts_usec, incl_len, orig_len = struct.unpack(self.header_format,
50 packet = self.file.read(incl_len)
51 if len(packet) != incl_len:
52 raise PcapException("end of file reading pcap packet data")
58 %(argv0)s: print pcap file packet data as hex
60 where FILE is a PCAP file.
62 The following options are also available:
63 -h, --help display this help message
64 -V, --version display version information\
65 """ % {'argv0': argv0}
68 if __name__ == "__main__":
71 options, args = getopt.gnu_getopt(sys.argv[1:], 'hV',
73 except getopt.GetoptException, geo:
74 sys.stderr.write("%s: %s\n" % (argv0, geo.msg))
77 for key, value in options:
78 if key in ['-h', '--help']:
80 elif key in ['-V', '--version']:
81 print "ovs-pcap (Open vSwitch) @VERSION@"
86 sys.stderr.write("%s: exactly 1 non-option argument required "
87 "(use --help for help)\n" % argv0)
90 reader = PcapReader(args[0])
92 packet = reader.read()
96 print binascii.hexlify(packet)
98 except PcapException, e:
99 sys.stderr.write("%s: %s\n" % (argv0, e))