104 lines
3.6 KiB
Python
104 lines
3.6 KiB
Python
#!/usr/bin/python
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# Copyright 2012 Google, Inc. All rights reserved.
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"""TestCreator creates test templates from pcap files."""
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import argparse
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import base64
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import glob
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import re
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import string
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import subprocess
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import sys
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class Packet(object):
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"""Helper class encapsulating packet from a pcap file."""
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def __init__(self, packet_lines):
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self.packet_lines = packet_lines
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self.data = self._DecodeText(packet_lines)
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@classmethod
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def _DecodeText(cls, packet_lines):
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packet_bytes = []
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# First line is timestamp and stuff, skip it.
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# Format: 0x0010: 0000 0020 3aff 3ffe 0000 0000 0000 0000 ....:.?.........
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for line in packet_lines[1:]:
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m = re.match(r'\s+0x[a-f\d]+:\s+((?:[\da-f]{2,4}\s)*)', line, re.IGNORECASE)
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if m is None: continue
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for hexpart in m.group(1).split():
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packet_bytes.append(base64.b16decode(hexpart.upper()))
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return ''.join(packet_bytes)
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def Test(self, name, link_type):
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"""Yields a test using this packet, as a set of lines."""
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yield '// testPacket%s is the packet:' % name
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for line in self.packet_lines:
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yield '// ' + line
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yield 'var testPacket%s = []byte{' % name
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data = list(self.data)
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while data:
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linebytes, data = data[:16], data[16:]
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yield ''.join(['\t'] + ['0x%02x, ' % ord(c) for c in linebytes])
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yield '}'
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yield 'func TestPacket%s(t *testing.T) {' % name
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yield '\tp := gopacket.NewPacket(testPacket%s, LinkType%s, gopacket.Default)' % (name, link_type)
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yield '\tif p.ErrorLayer() != nil {'
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yield '\t\tt.Error("Failed to decode packet:", p.ErrorLayer().Error())'
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yield '\t}'
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yield '\tcheckLayers(p, []gopacket.LayerType{LayerType%s, FILL_ME_IN_WITH_ACTUAL_LAYERS}, t)' % link_type
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yield '}'
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yield 'func BenchmarkDecodePacket%s(b *testing.B) {' % name
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yield '\tfor i := 0; i < b.N; i++ {'
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yield '\t\tgopacket.NewPacket(testPacket%s, LinkType%s, gopacket.NoCopy)' % (name, link_type)
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yield '\t}'
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yield '}'
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def GetTcpdumpOutput(filename):
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"""Runs tcpdump on the given file, returning output as string."""
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return subprocess.check_output(
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['tcpdump', '-XX', '-s', '0', '-n', '-r', filename])
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def TcpdumpOutputToPackets(output):
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"""Reads a pcap file with TCPDump, yielding Packet objects."""
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pdata = []
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for line in output.splitlines():
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if line[0] not in string.whitespace and pdata:
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yield Packet(pdata)
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pdata = []
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pdata.append(line)
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if pdata:
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yield Packet(pdata)
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def main():
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class CustomHelpFormatter(argparse.ArgumentDefaultsHelpFormatter):
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def _format_usage(self, usage, actions, groups, prefix=None):
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header =('TestCreator creates gopacket tests using a pcap file.\n\n'
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'Tests are written to standard out... they can then be \n'
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'copied into the file of your choice and modified as \n'
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'you see.\n\n')
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return header + argparse.ArgumentDefaultsHelpFormatter._format_usage(
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self, usage, actions, groups, prefix)
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parser = argparse.ArgumentParser(formatter_class=CustomHelpFormatter)
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parser.add_argument('--link_type', default='Ethernet', help='the link type (default: %(default)s)')
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parser.add_argument('--name', default='Packet%d', help='the layer type, must have "%d" inside it')
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parser.add_argument('files', metavar='file.pcap', type=str, nargs='+', help='the files to process')
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args = parser.parse_args()
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for arg in args.files:
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for path in glob.glob(arg):
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for i, packet in enumerate(TcpdumpOutputToPackets(GetTcpdumpOutput(path))):
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print '\n'.join(packet.Test(
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args.name % i, args.link_type))
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if __name__ == '__main__':
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main()
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