I'm using python3 and nfqueue to modify packets on-the-fly.
Scapy version: 2.4.1
Python's NetfilterQueue (PyPi) has methods to convert packets to "scapy-compatible" strings/bytes and vice versa, these are:
get_payload, that returns scapy-compatible string in python 2, BYTES in python 3.
set_payload, that sets the packet's payload after we were done with scapy.
After I use get_payload, I can use scapy's IP() method to modify sections of the packet pleasingly. However, when I'm done, I'm left with an object of type "IP", which I want to convert to type "bytes" (to be able to use set_payload on it).
('nnnn' is the actual packets data in this case)
running...
<class 'scapy.layers.inet.IP'>
b'E\x00\x008\x82\x00@\x00@\x06\xba\xbd\x7f\x00\x00\x01\x7f\x00\x00\x01\xeaj\x1f\x91(\x02\xb9\xffq\xa4\xd6\xbe\x80\x18\x02\x00\xf2W\x00\x00\x01\x01\x08\n\xa8b\x11*\xa8b\x11*nnnn'
b'nnnn'
Argument 'payload' has incorrect type (expected bytes, got IP)
How do I convert type scapy.layers.inet.IP to type "bytes" in python3?
From the source code, you can either call build method or you can pass your IP object to bytes directly as IP implements the __bytes__ dunder method:
from scapy.layers.inet import IP
p = IP(dst="github.com")
print(p) # b'E\x00\x00\x14\x00\x01\x00\x00@\x00l\x82\n\x0c\x02\x05\x8cRv\x04'
print(p.build()) # b'E\x00\x00\x14\x00\x01\x00\x00@\x00l\x82\n\x0c\x02\x05\x8cRv\x04'
print(bytes(p)) # b'E\x00\x00\x14\x00\x01\x00\x00@\x00l\x82\n\x0c\x02\x05\x8cRv\x04'
print(raw(p)) # b'E\x00\x00\x14\x00\x01\x00\x00@\x00l\x82\n\x0c\x02\x05\x8cRv\x04'