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"""Create dynamic network layers of
Application Layer
Transport Layer
Network Layer
Data Link Layer
Physical Layer (No Need to implement)
"""
import ipaddress
class LayerParser(object):
"""
Base layer class
"""
def __init__(self, data):
"""
docstring
"""
self.data = data
self.header_struct = self.get_header_struct()
self.sliced_data = {}
self.analysis()
def get_header_struct(self):
return {}
def pretty_print(self):
for part, data in self.sliced_data.items():
print(f"{part}: {hex(int(data, 2))}")
def analysis(self):
current_pos = 0
for part, length in self.header_struct.items():
end_pos = current_pos + length
self.sliced_data[part] = self.data[current_pos:end_pos]
current_pos = end_pos
def to_upper_layer(self):
pass
class EthernetParser(LayerParser):
"""
Ethernet_II Layer
refer to https://en.wikipedia.org/wiki/Ethernet_frame
in this layer, MAC address is used as id
"""
def get_header_struct(self):
return {
"DMAC": 6 * 8,
"SMAC": 6 * 8,
"Type": 2 * 8,
}
def next_protocal(self):
type_id = int(self.sliced_data["Type"], 2)
if type_id == 0x0800:
return "ipv4"
elif type_id == 0x0806:
return "arp"
elif type_id == 0x86DD:
return "ipv6"
def to_upper_layer(self):
return self.data[14 * 8:]
class LoopbackParser(LayerParser):
"""
Virtual Ethernet Layer, implemented for localhost
the first 4 bytes are
0000 1e 00 00 00
"""
HINT = "00011110" + "0" * (3 * 8)
def to_upper_layer(self):
return self.data[4 * 8:]
def next_protocal(self):
return "ipv6"
class IPv6Parser(LayerParser):
"""
NetworkParser, deal with IPv6
refer to https://en.wikipedia.org/wiki/IPv6_packet
"""
def get_header_struct(self):
return {
"protocol_version": 1 * 4,
"traffic_class": 2 * 4,
"flow_label": 5 * 4,
"payload_length": 4 * 4,
"next_protocol": 2 * 4,
"hop_limit": 2 * 4,
"source_address": 32 * 4,
"dst_address": 32 * 4,
}
def to_upper_layer(self):
return self.data[40 * 8:]
@property
def s_ip(self):
return ipaddress.IPv6Address(
int(self.sliced_data["source_address"], 2))
@property
def d_ip(self):
return ipaddress.IPv6Address(
int(self.sliced_data["dst_address"], 2))
class IPv4Parser(LayerParser):
"""
NetworkParser, deal with IPv4
refer to https://en.wikipedia.org/wiki/IPv4#Header
"""
def get_header_struct(self):
return {
"protocol_version": 1 * 4,
"IHL": 1 * 4,
"DSCP": 6,
"ECN": 2,
"Total_Length": 2 * 8,
"Identification": 2 * 8,
"Flags": 3,
"Fragment Offset": 2 * 8 - 3,
"Time To Live": 8,
"next_protocol": 8,
"Header_Checksum": 2 * 8,
"source_address": 4 * 8,
"dst_address": 4 * 8,
}
def analysis(self):
super().analysis()
self.header_length = int(self.sliced_data["IHL"], 2) * 32
def to_upper_layer(self):
return self.data[self.header_length:]
@property
def s_ip(self):
return ipaddress.IPv4Address(
int(self.sliced_data["source_address"], 2))
@property
def d_ip(self):
return ipaddress.IPv4Address(
int(self.sliced_data["dst_address"], 2))
class TCPParser(LayerParser):
"""
TCP layer data Parser
refer to https://en.wikipedia.org/wiki/Transmission_Control_Protocol
"""
def get_header_struct(self):
return {
"source_port": 8 * 2,
"dst_port": 8 * 2,
"sequence_number": 8 * 4,
"ack_number": 8 * 4,
"data_offset": 4,
"reserved": 3,
"ns": 1,
"cwr": 1,
"ece": 1,
"urg": 1,
"ack": 1,
"psh": 1,
"rst": 1,
"syn": 1,
"fin": 1,
"window_size": 8 * 2,
"checksum": 8 * 2,
"urgent_pointer": 8 * 2
}
def analysis(self):
super().analysis()
self.header_length = int(self.sliced_data["data_offset"], 2) * 32
def to_upper_layer(self):
return self.data[header_length:]
class MyShark(object):
"""
Oh My WireShark!
"""
def __init__(self, packets):
self.packets = packets
def get_stream(self, packet):
stream = [packet]
s_ip = packet.s_ip
d_ip = packet.d_ip
s_port = packet.s_port
d_port = packet.d_port
for p in self.packets:
if all([
s_ip == p.s_ip,
d_ip == p.d_ip,
s_port == p.s_port,
d_port == p.d_port,
]):
stream.append(p)
return stream
def summary(self):
"""pretty print summarize info"""
tag_dict = {}
for p in shark.packets:
src = str(p.s_ip) + ':' + str(p.s_port)
dst = str(p.d_ip) + ':' + str(p.d_port)
tag = f"source: {src:<23} dst: {dst:<23} protocol: {p.protocol}"
if tag in tag_dict.keys():
tag_dict[tag] += 1
else:
tag_dict[tag] = 1
for t, c in tag_dict.items():
print(t, " Count: ", c)
class MyPacket(object):
"""
Store all layer info in this class
"""
def __init__(self, pyshark_packet):
"""
init packet with bin string
"""
self.packet = pyshark_packet
rb = self.packet.get_raw_packet()
raw_hex = rb.hex()
raw_bin = bin(int(raw_hex, base=16))[2:].zfill(len(rb) * 8)
if raw_bin.startswith(LoopbackParser.HINT):
self.ethernet_layer = LoopbackParser(raw_bin)
else:
self.ethernet_layer = EthernetParser(raw_bin)
if self.ethernet_layer.next_protocal() == "ipv6":
data = self.ethernet_layer.to_upper_layer()
self.ip_layer = IPv6Parser(data)
elif self.ethernet_layer.next_protocal() == "ipv4":
data = self.ethernet_layer.to_upper_layer()
self.ip_layer = IPv4Parser(data)
else:
raise ValueError("protrocal {} is not implemented".format(
self.ethernet_layer.next_protocal))
tcp_data = self.ip_layer.to_upper_layer()
self.tcp_layer = TCPParser(tcp_data)
@property
def s_ip(self):
return self.ip_layer.s_ip
@property
def d_ip(self):
return self.ip_layer.d_ip
@property
def s_port(self):
return int(self.tcp_layer.sliced_data["source_port"], 2)
@property
def d_port(self):
return int(self.tcp_layer.sliced_data["dst_port"], 2)
@property
def protocol(self):
code = self.ip_layer.sliced_data["next_protocol"]
code = int(code, 2)
if code == 0x06:
return "TCP"
elif code == 0x11:
return "UDP"
else:
return "Unknown"
if __name__ == "__main__":
import pyshark
from pathlib import Path
import os
fp = str(Path.home()) + '/Downloads/lo0_1.pcapng.gz'
if os.path.exists(fp):
capture = pyshark.FileCapture(fp,
use_json=True,
include_raw=True)
else:
capture = pyshark.LiveCapture(interface='lo0', output_file=fp)
capture.set_debug()
capture.sniff(timeout=10)
packets = []
for p in capture:
try:
packets.append(MyPacket(p))
except ValueError as identifier:
pass
shark = MyShark(packets)
shark.summary()
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