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#!/usr/bin/env python3
#
# Copyright 2019, Dario Lombardo <lomato@gmail.com>
#
# Wireshark - Network traffic analyzer
# By Gerald Combs <gerald@wireshark.org>
# Copyright 1998 Gerald Combs
#
# SPDX-License-Identifier: GPL-2.0-or-later
#
# This script generates a Wireshark skeleton dissector, based on the example in the doc/ directory.
#
# Example usage:
#
# generate-dissector.py --name "My Self" --email "myself@example.com" --protoname "The dumb protocol"
# --protoshortname DUMB --protoabbrev dumb --license GPL-2.0-or-later --years "2019-2020"
#
import argparse
from datetime import datetime
import os
parser = argparse.ArgumentParser(description='The Wireshark Dissector Generator')
parser.add_argument("--name", help="The author of the dissector", required=True)
parser.add_argument("--email", help="The email address of the author", required=True)
parser.add_argument("--protoname", help="The name of the protocol", required=True)
parser.add_argument("--protoshortname", help="The protocol short name", required=True)
parser.add_argument("--protoabbrev", help="The protocol abbreviation", required=True)
parser.add_argument("--license", help="The license for this dissector (please use a SPDX-License-Identifier). If omitted, %(default)s will be used", default="GPL-2.0-or-later")
parser.add_argument("--years", help="Years of validity for the license. If omitted, the current year will be used", default=str(datetime.now().year))
parser.add_argument("-f", "--force", action='store_true', help="Force overwriting the dissector file if it already exists")
parser.add_argument("-p", "--plugin", action='store_true', help="Create as a plugin. Default is to create in epan")
def wsdir():
return os.path.abspath(os.path.join(os.path.dirname(__file__), ".."))
def output_dir(args):
if args.plugin:
os.makedirs(os.path.join(wsdir(), "plugins/epan/" + args.protoabbrev), exist_ok=True)
return os.path.join(wsdir(), "plugins/epan/" + args.protoabbrev)
return os.path.join(wsdir(), "epan/dissectors")
def output_file(args):
return os.path.join(output_dir(args), "packet-" + args.protoabbrev + ".c")
def read_skeleton(filename):
skeletonfile = os.path.join(wsdir(), "doc/" + filename)
print("Reading skeleton file: " + skeletonfile)
return open(skeletonfile).read()
def replace_fields(buffer, args):
print("Replacing fields in skeleton")
output = buffer\
.replace("YOUR_NAME", args.name)\
.replace("YOUR_EMAIL_ADDRESS", args.email)\
.replace("PROTONAME", args.protoname)\
.replace("PROTOSHORTNAME", args.protoshortname)\
.replace("PROTOABBREV", args.protoabbrev)\
.replace("FIELDNAME", "Sample Field")\
.replace("FIELDABBREV", "sample_field")\
.replace("FT_FIELDTYPE", "FT_STRING")\
.replace("FIELDDISPLAY", "BASE_NONE")\
.replace("FIELDCONVERT", "NULL")\
.replace("BITMASK", "0x0")\
.replace("FIELDDESCR", "NULL")\
.replace("MAX_NEEDED_FOR_HEURISTICS", "1")\
.replace("TEST_HEURISTICS_FAIL", "0")\
.replace("ENC_xxx", "ENC_NA")\
.replace("EXPERTABBREV", "expert")\
.replace("PI_GROUP", "PI_PROTOCOL")\
.replace("PI_SEVERITY", "PI_ERROR")\
.replace("TEST_EXPERT_condition", "0")\
.replace("const char *subtree", "\"\"")\
.replace("LICENSE", args.license)\
.replace("YEARS", args.years)
return output
def write_dissector(buffer, args):
ofile = output_file(args)
if os.path.isfile(ofile) and not args.force:
raise Exception("The file " + ofile + " already exists. You're likely overwriting an existing dissector.")
print("Writing output file: " + ofile)
return open(ofile, "w").write(buffer)
def patch_makefile(args):
if args.plugin:
cmakefile = os.path.join(wsdir(), "CMakeLists.txt")
patchline = "\t\tplugins/epan/" + args.protoabbrev
groupstart = "set(PLUGIN_SRC_DIRS"
else:
cmakefile = os.path.join(wsdir(), "epan/dissectors/CMakeLists.txt")
patchline = "\t${CMAKE_CURRENT_SOURCE_DIR}/packet-" + args.protoabbrev + ".c"
groupstart = "set(DISSECTOR_SRC"
print("Patching makefile: " + cmakefile)
output = ""
in_group = False
patched = False
for line in open(cmakefile):
line_strip = line.strip()
if in_group and line_strip == ")":
in_group = False
if in_group and not patched and line_strip > patchline:
output += patchline + "\n"
patched = True
if line_strip == groupstart:
in_group = True
if line_strip != patchline:
output += line
open(cmakefile, "w").write(output)
def write_plugin_makefile(args):
if not args.plugin:
return True
buffer = replace_fields(read_skeleton("CMakeLists-PROTOABBREV.txt"), args)
ofile = os.path.join(output_dir(args), "CMakeLists.txt")
print("Writing output file: " + ofile)
return open(ofile, "w").write(buffer)
def print_header():
print("")
print("**************************************************")
print("* Wireshark skeleton dissector generator *")
print("* *")
print("* Generate a new dissector for your protocol *")
print("* starting from the skeleton provided in the *")
print("* doc directory. *")
print("* *")
print("* Copyright 2019 Dario Lombardo *")
print("**************************************************")
print("")
def print_trailer(args):
print("")
print("The skeleton for the dissector of the " + args.protoshortname + " protocol has been generated.")
print("Please review/extend it to match your specific criteria.")
print("")
if __name__ == '__main__':
print_header()
args = parser.parse_args()
buffer = replace_fields(read_skeleton("packet-PROTOABBREV.c"), args)
write_dissector(buffer, args)
patch_makefile(args)
write_plugin_makefile(args)
print_trailer(args)
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