dbc to scapy

dbc_to_scapy.py

#!/usr/bin/env python3
import canmatrix.formats
import sys
import os

if len(sys.argv) < 2:
    exit()
file_name = sys.argv[1]
cm = canmatrix.formats.loadp_flat(file_name)

scapy_decoder = """
from scapy.packet import Packet
from scapy.packet import bind_layers
from scapy.fields import *
from scapy.layers.can import *


class DBC(CAN):
    name = 'DBC'
    fields_desc = [
        FlagsField('flags', 0, 3, ['error',
                                   'remote_transmission_request',
                                   'extended']),
        XBitField('arbitration_id', 0, 29),
        ByteField('length', None),
        ThreeBytesField('reserved', 0),
    ]

"""

def get_fmt(signal):

    if signal.is_little_endian:
        if signal.is_float:
            fmt = "<f"
        elif signal.is_signed:
            fmt = "<b" 
        else:
            fmt = "<B" 
    else:
        if signal.is_float:
            fmt = ">f"
        elif signal.is_signed:
            fmt = ">b"
        else:
            fmt = ">B" 
    
    return fmt

for frame in cm.frames:
    scapy_decoder += "class " + frame.name + "(Packet):\n"
    scapy_decoder += "    fields_desc = [ \n"
    signal_collection = []
    for signal_group in frame.signalGroups:
        for signal in signal_group.signals:
            signal_collection.append(signal)

    for signal in frame.signals:   
        signal_collection.append(signal)
            
    for signal in signal_collection:   
        scapy_decoder += '        SignalField("{}", default=0, start={}, size={}, scaling={}, offset={}, unit="{}", fmt="{}"),\n'.format(
        signal.name, signal.get_startbit(bit_numbering=1), signal.size, signal.factor, signal.offset, signal.unit, get_fmt(signal))
    scapy_decoder += "    ]\n\n"
    
for frame in cm.frames:
    if frame.arbitration_id.extended:
        scapy_decoder += "bind_layers(DBC, " + frame.name + ", arbitration_id = " + hex(frame.arbitration_id.id) + ", flags = extended)\n"
    else:
        scapy_decoder += "bind_layers(DBC, " + frame.name + ", arbitration_id = " + hex(frame.arbitration_id.id) + ")\n"

out_file_name,_ = os.path.splitext(file_name)
out_file_name += ".py"
with open(out_file_name, "w") as fd:
    fd.write(scapy_decoder)
    fd.close