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How to parse a captured package in python?

I have a raw capture package using python sockets:

s = socket.socket(socket.AF_PACKET, socket.SOCK_RAW, socket.ntohs(0x0003))

while True:
    message = s.recv(4096)
    test = []
    print(len(message))
    print(repr(message))

I assumed that the returned package would be in hexadecimal string format, however the printout print(repr(message))would get me something like this:

b'\x00\x1b\xac\x00Gd\x00\x14\xd1+\x1f\x19\x05\n\x124VxC!UUUU\x00\x00\x00\x00\xcd\xcc\xcc=\xcd\xccL>\x9a\x99\x99>\xcd\xcc\xcc>\x00\x00\x00?\x9a\x......'

which has strange non-hexadecimal characters such as !UUUUor =. What encoding is it and how can I decode a packet?

I know that a package looks ahead of time since I am the one who generates packages using winpcapy :

from ctypes import *
from winpcapy import *
import zlib
import binascii
import time


from ChanPackets import base, FrMessage, FrTodSync, FrChanConfig, FlChan, RlChan


while (1):

    now = time.time()

    errbuf = create_string_buffer(PCAP_ERRBUF_SIZE)
    fp = pcap_t
    deviceName = b'\\Device\\NPF_{8F5BD2E9-253F-4659-8256-B3BCD882AFBC}'
    fp = pcap_open_live(deviceName, 65536, 1, 1000, errbuf)

    if not bool(fp):
        print ("\nUnable to open the adapter.  %s is not supported by WinPcap\n" % deviceName)
        sys.exit(2)

    # FrMessage is a custom class that creates the packet
    test = FrMessage('00:1b:ac:00:47:64', '00:14:d1:2b:1f:19', 0x12345678, 0x4321, 0x55555555, list(i/10 for i in range(320)))

    # test.get_Raw_Packet() returns a c_bytes array needed for winpcap to send the packet
    if (pcap_sendpacket(fp, test.get_Raw_Packet(), test.packet_size) != 0):
        print ("\nError sending the packet: %s\n" % pcap_geterr(fp))
        sys.exit(3)


    elapsed = time.time() - now
    if elapsed < 0.02 and elapsed > 0:
        time.sleep(0.02 - elapsed)

    pcap_close(fp)

Note. I would like to get an array of hexadecimal values ​​representing each byte

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2 answers

?

, , bytes Python. , \xab 0xab (171).

, !UUUU =

ASCII , .. \x55 U.

. . , , Ethernet, scapy (Python 2):

>>> b = '\x00\x02\x157\xa2D\x00\xae\xf3R\xaa\xd1\x08\x00E\x00\x00C\x00\x01\x00\x00@\x06x<\xc0\xa8\x05\x15B#\xfa\x97\x00\x14\x00P\x00\x00\x00\x00\x00\x00\x00\x00P\x02 \x00\xbb9\x00\x00GET /index.html HTTP/1.0 \n\n'
>>> c = Ether(b)
>>> c.hide_defaults()
>>> c
<Ether  dst=00:02:15:37:a2:44 src=00:ae:f3:52:aa:d1 type=0x800 |
<IP  ihl=5L len=67 frag=0 proto=tcp chksum=0x783c src=192.168.5.21 dst=66.35.250.151 |
<TCP  dataofs=5L chksum=0xbb39 options=[] |
<Raw  load='GET /index.html HTTP/1.0 \n\n' |>>>>

,

binascii.hexlify():

>>> pkt = b'\x00\x1b\xac\x00Gd\x00'
>>> import binascii
>>> binascii.hexlify(pkt)
b'001bac00476400'

:

>>> hexvalue = binascii.hexlify(pkt).decode()
>>> [hexvalue[i:i+2] for i in range(0, len(hexvalue), 2)]
['00', '1b', 'ac', '00', '47', '64', '00']
+4

python scapy, IP(), TCP(), UDP() ..

import sys
import socket
from scapy.all import *
s = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_TCP)
while 1:
    packet = s.recvfrom(2000);
    packet = packet[0]
    ip = IP(packet)
    ip.show()
0

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