How to generate an Ethernet OAM PDU in Scapy?

Question

linux

Hello! I just can’t catch up with how to form Ethernet OAM packets / PDUs there, specifying their values ​​​​in the type, subtype, flags, code fields. Is this even possible in Scapy? If not, are there tools that allow you to generate and send such PDUs?

Answer 1

Is this even possible in Scapy?

You can create a frame using the constructor e=Ether(src='AA:AA:AA:AA:AA:AA',dst='01:80:c2:00:00:02',type=0x8809), and so on set the value of the data field yourself (e.payload=data, where data is of the Packet or str type)
Example (the size of the fields may not be quite correct):

e=Ether(src='AA:AA:AA:AA:AA:AA',dst='01:80:c2:00:00:02',type=0x8809)
class EthernetOAM(Packet):
    name='Ethernet OAM'
    fields_desc=[
         ByteField('Subtype',3),
         ByteField('Flags',0),
         ByteField('Code',0),
    ]
OAM=EtherOAM()
OAM.payload="data+padding"
e.payload=OAM
OAM
>>> <EthernetOAM  |<Raw  load='data+padding' |>>
e
>>> <Ether  dst=01:80:c2:00:00:02 src=AA:AA:AA:AA:AA:AA type=0x8809 |<EthernetOAM  |<Raw  load='data+padding' |>>>

If not, are there tools that allow you to generate and send such PDUs?

There are many tools (for example, trafgen or mausezahn as part of the netsniff-ng package), but you will most likely have to form the data field yourself.

Answer 2

Thank you throughtheether! Your answer helped me. I figured out which direction to go)) I'll add it a little more from myself) Maybe someone will need it))
I created a test_packet.py file with something like this

#! /usr/bin/env python
#! /usr/bin/env python

# Set log level to benefit from Scapy warnings
import logging
logging.getLogger("scapy").setLevel(1)

from scapy.all import *

class EthernetOAM(Packet):
  name = "Ethernet OAM"
  fields_desc = [ 
                                XByteField("Subtype", 0x03),
        XByteField("Flags1", 	0x00),
        XByteField("Flags2", 	0x02), 
        XByteField("Code",	0x00)
         ]

if __name__ == "__main__":
  interact(mydict=globals(), mybanner="I am Batman")

#End of file

ran:
#sudo python test_packet.py
>>> e = Ether(src='AA:AA:AA:AA:AA:AA',dst='01:80:c2:00:00:02',type=0x8809 )/EthernetOAM()
>>>sendp(e)
In principle, that's all I needed) It's
best of course to smoke the official documentation:
www.secdev.org/projects/scapy/build_your_own_tools.html
www.secdev.org/projects/scapy /doc/build_dissect.html