def write_dict_to_csv(self, dict_fp, out_file):
header = PCAPToCSV.get_csv_header(dict_fp)
with gzip_writer(out_file) as f_out:
writer = csv.DictWriter(f_out, fieldnames=header)
writer.writeheader()
try:
with gzip_reader(dict_fp) as f_in:
for line in f_in:
writer.writerow(json.loads(line.strip()))
except Exception as e: # pragma: no cover
self.logger.error(f'Failed to write to CSV because: {e}')
def get_tshark_packet_data(self, pcap_file, dict_fp):
options = '-n -V -Tjson'
try:
process = subprocess.Popen(shlex.split(' '.join(
['tshark', '-r', pcap_file, options])),
stdout=subprocess.PIPE)
with gzip_writer(dict_fp) as f_out:
for item in self.json_packet_records(process):
f_out.write(json.dumps(self.flatten_json(item)) + '\n')
except Exception as e: # pragma: no cover
self.logger.error(f'{e}')
def combine_csvs(out_paths, combined_path):
# First determine the field names from the top line of each input file
fieldnames = {'filename'}
for filename in out_paths:
with gzip_reader(filename) as f_in:
reader = csv.reader(f_in)
fieldnames.update({header for header in next(reader)})
# Then copy the data
with gzip_writer(combined_path) as f_out:
writer = csv.DictWriter(f_out, fieldnames=fieldnames)
writer.writeheader()
for filename in out_paths:
with gzip_reader(filename) as f_in:
reader = csv.DictReader(f_in)
for line in reader:
line['filename'] = filename.split('/')[-1].split(
'csv.gz')[0]
writer.writerow(line)
PCAPToCSV.cleanup_files([filename])
def get_tshark_conv_data(self, pcap_file, dict_fp):
# TODO (add a summary of other packets with protocols?)
output = ''
try:
# TODO perhaps more than just tcp/udp in the future
options = '-n -q -z conv,tcp -z conv,udp'
output = subprocess.check_output(
shlex.split(' '.join(['tshark', '-r', pcap_file, options])))
output = output.decode('utf-8')
except Exception as e: # pragma: no cover
self.logger.error(f'{e}')
in_block = False
name = None
results = {}
for line in output.split('\n'):
if line.startswith('==='):
if in_block:
in_block = False
name = None
continue
else:
in_block = True
continue
if in_block:
if not name:
name = ''.join(line.split(':')).strip()
results[name] = ''
continue
elif not line.startswith('Filter:') and line != '':
results[name] += line + '\n'
with gzip_writer(dict_fp) as f_out:
for result in results.keys():
if 'Conversations' in result:
transport_proto = result.split()[0]
# handle conversation parsing
for line in results[result].split('\n'):
if line == '' or line.startswith(' '):
# header or padding, dicard
continue
else:
# TODO perhaps additional features can be extracted for flows from tshark
src, _, dst, frames_l, bytes_l, frames_r, bytes_r, frames_total, bytes_total, rel_start, duration = line.split(
)
conv = {
'Source': src.rsplit(':', 1)[0],
'Source Port': src.rsplit(':', 1)[1],
'Destination': dst.rsplit(':', 1)[0],
'Destination Port': dst.rsplit(':', 1)[1],
'Transport Protocol': transport_proto,
'Frames to Source': frames_l,
'Bytes to Source': bytes_l,
'Frames to Destination': frames_r,
'Bytes to Destination': bytes_r,
'Total Frames': frames_total,
'Total Bytes': bytes_total,
'Relative Start': rel_start,
'Duration': duration
}
f_out.write(json.dumps(conv) + '\n')
def get_pyshark_packet_data(self, pcap_file, dict_fp):
all_protocols = set()
pcap_file_short = ntpath.basename(pcap_file)
with gzip_writer(dict_fp) as f_out:
with pyshark.FileCapture(pcap_file,
use_json=True,
include_raw=True,
keep_packets=False,
custom_parameters=[
'-o',
'tcp.desegment_tcp_streams:false',
'-n'
]) as cap:
for packet in cap:
packet_dict = {}
packet_dict['filename'] = pcap_file_short
frame_info = packet.frame_info._all_fields
for key in frame_info:
packet_dict[key] = frame_info[key]
# can overflow the field size for csv
#packet_dict['raw_packet'] = packet.get_raw_packet()
layers = str(packet.layers)
packet_dict['layers'] = layers
str_layers = layers[1:-1].split(', ')
for str_layer in str_layers:
# ignore raw layers
if 'RAW' not in str_layer:
all_protocols.add(str_layer)
# only include specified protocols due to unknown parsing for some layers
if str_layer in self.PROTOCOLS:
layer_info = getattr(
packet,
str_layer.split()[0][1:].lower())._all_fields
# check for nested dicts, one level deep
for key in layer_info:
# DNS doesn't parse well
if isinstance(
layer_info[key],
dict) and str_layer != '<DNS Layer>':
for inner_key in layer_info[key]:
packet_dict[inner_key] = layer_info[
key][inner_key]
else:
packet_dict[key] = layer_info[key]
# clean up records
packet_dict_copy = deepcopy(packet_dict)
keys = packet_dict_copy.keys()
for key in keys:
if not key[0].isalpha(
) or key == 'tcp.payload_raw' or key == 'tcp.payload':
del packet_dict[key]
f_out.write(json.dumps(packet_dict) + '\n')
for protocol in self.PROTOCOLS:
if protocol in all_protocols:
all_protocols.remove(protocol)
if all_protocols:
self.logger.warning(
f'Found the following other layers in {pcap_file_short} that were not added to the CSV: {all_protocols}'
)
def get_writer(out_file, use_gzip):
if use_gzip:
return gzip_writer(out_file)
return open(out_file, 'w')
