"installing" Kaitai Struct Python - python-3.x

Question

I need help with installing Kaitai Struct on my Laptop.
I installed python-kaitaistruct and compiled the network files.
But i get an import error:
Traceback (most recent call last):
File "test2.py", line 1, in <module>
from ethernet_frame import *
File "/home/bene/python/ethernet_frame.py", line 15, in <module>
from ipv6_packet import Ipv6Packet
File "/home/bene/python/ipv6_packet.py", line 17, in <module>
from ipv4_packet import Ipv4Packet
File "/home/bene/python/ipv4_packet.py", line 17, in <module>
from ipv6_packet import Ipv6Packet
ImportError: cannot import name 'Ipv6Packet
My folder looks like this:
insgesamt 76K
drwxr-xr-x 3 bene bene 330 19. Jan 16:03 .
drwx------ 24 bene bene 4,0K 19. Jan 16:06 ..
-rw-r--r-- 1 bene bene 42 5. Jan 12:38 country.py
-rw-r--r-- 1 bene bene 8,0K 5. Jan 12:09 dns_packet.py
-rw-r--r-- 1 bene bene 1,6K 5. Jan 12:09 ethernet_frame.py
-rw-r--r-- 1 bene bene 3,0K 5. Jan 12:09 icmp_packet.py
-rw-r--r-- 1 bene bene 7,7K 5. Jan 12:09 ipv4_packet.py
-rw-r--r-- 1 bene bene 2,7K 5. Jan 12:09 ipv6_packet.py
-rw-r--r-- 1 bene bene 6,4K 5. Jan 12:09 microsoft_network_monitor_v2.py
-rw-r--r-- 1 bene bene 7,0K 5. Jan 12:09 pcap.py
drwxr-xr-x 2 bene bene 180 5. Jan 12:12 __pycache__
-rw-r--r-- 1 bene bene 1,1K 5. Jan 12:09 tcp_segment.py
-rw-r--r-- 1 bene bene 518 5. Jan 12:32 test1.py
-rw-r--r-- 1 bene bene 596 19. Jan 15:56 test2.py
-rw-r--r-- 1 bene bene 667 5. Jan 12:38 test.py
-rw-r--r-- 1 bene bene 880 5. Jan 12:09 udp_datagram.py
-rw-r--r-- 1 bene bene 986 5. Jan 12:09 windows_systemtime.py
and the file i executed:
from ethernet_frame import *
import socket
s = socket.socket(socket.AF_PACKET,socket.SOCK_RAW,socket.ntohs(3))
def network(buf):
io = BytesIO(buf)
ksio = KaitaiStream(io)
pkt = EthernetFrame(ksio)
dummy = pkt.ipv4_body.src_ip_addr
print(dummy)
while True:
p = s.recvfrom(65565)
network(p)
Can someone help me maybe i installed it wrong?
Or a Full Guide how to install and use it would be cool :DD
Thank you <3

Answer 1

I had a similar issue and after checking the .py file created by the compiler I found editing the import sequence solved the issue. Example:
import ipv4_packet was causing the same error as you have.
I checked ipv4_packet.py and it had an import statement from ipv6_packet import Ipv6Packet.
# This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild
from pkg_resources import parse_version
from kaitaistruct import __version__ as ks_version, KaitaiStruct, KaitaiStream, BytesIO
from enum import Enum
if parse_version(ks_version) < parse_version('0.7'):
raise Exception("Incompatible Kaitai Struct Python API: 0.7 or later is required, but you have %s" % (ks_version))
from udp_datagram import UdpDatagram
from tcp_segment import TcpSegment
from ipv6_packet import Ipv6Packet
from icmp_packet import IcmpPacket
class Ipv4Packet(KaitaiStruct):
class ProtocolEnum(Enum):
ipv6_packet inturn tries to import the class from ipv4_packet: from ipv4_packet import Ipv4Packet, and causes the import error. If the lines (ipv4_packet .py):
from udp_datagram import UdpDatagram
from tcp_segment import TcpSegment
from ipv6_packet import Ipv6Packet
from icmp_packet import IcmpPacket
are moved to after the class definition there is no error.
Just playing around with Kaitai Struct for the first time this morning, I am sure this does not need to be done manually and there is an issue in the compilation I/we are doing, but this works if you just want to have a quick play.

Answer 2

I believe you should put the files that Kaitai Struct generated for you somewhere where Python will find it. Probably the simplest solution so far would be to just keep it in current directory and launch test2.py with something like:
PYTHONPATH=. python ./test2.py
Alternatively, if you want to keep everything in the same directory, newer compilers allow you to specify --python-package . to generate package imports which seek stuff in current directory.