tools/generate-dissector.py

   1 #!/usr/bin/env python3
   2 #
   3 # Copyright 2019, Dario Lombardo <lomato@gmail.com>
   4 #
   5 # Wireshark - Network traffic analyzer
   6 # By Gerald Combs <gerald@wireshark.org>
   7 # Copyright 1998 Gerald Combs
   8 #
   9 # SPDX-License-Identifier: GPL-2.0-or-later
  10 #
  11 # This script generates a Wireshark skeleton dissector, based on the example in the doc/ directory.
  12 #
  13 # Example usage:
  14 #
  15 # generate-dissector.py --name "My Self" --email "myself@example.com" --protoname "The dumb protocol"
  16 #   --protoshortname DUMB --protoabbrev dumb --license GPL-2.0-or-later --years "2019-2020"
  17 #
  18
  19 import argparse
  20 from datetime import datetime
  21 import os
  22
  23
  24 parser = argparse.ArgumentParser(description='The Wireshark Dissector Generator')
  25 parser.add_argument("--name", help="The author of the dissector", required=True)
  26 parser.add_argument("--email", help="The email address of the author", required=True)
  27 parser.add_argument("--protoname", help="The name of the protocol", required=True)
  28 parser.add_argument("--protoshortname", help="The protocol short name", required=True)
  29 parser.add_argument("--protoabbrev", help="The protocol abbreviation", required=True)
  30 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")
  31 parser.add_argument("--years", help="Years of validity for the license. If omitted, the current year will be used", default=str(datetime.now().year))
  32 parser.add_argument("-f", "--force", action='store_true', help="Force overwriting the dissector file if it already exists")
  33 parser.add_argument("-p", "--plugin", action='store_true', help="Create as a plugin. Default is to create in epan")
  34
  35
  36 def wsdir():
  37     return os.path.abspath(os.path.join(os.path.dirname(__file__), ".."))
  38
  39
  40 def output_dir(args):
  41     if args.plugin:
  42         os.makedirs(os.path.join(wsdir(), "plugins/epan/" + args.protoabbrev), exist_ok=True)
  43         return os.path.join(wsdir(), "plugins/epan/" + args.protoabbrev)
  44     return os.path.join(wsdir(), "epan/dissectors")
  45
  46
  47 def output_file(args):
  48     return os.path.join(output_dir(args), "packet-" + args.protoabbrev + ".c")
  49
  50
  51 def read_skeleton(filename):
  52     skeletonfile = os.path.join(wsdir(), "doc/" + filename)
  53     print("Reading skeleton file: " + skeletonfile)
  54     return open(skeletonfile).read()
  55
  56
  57 def replace_fields(buffer, args):
  58     print("Replacing fields in skeleton")
  59     output = buffer\
  60         .replace("YOUR_NAME", args.name)\
  61         .replace("YOUR_EMAIL_ADDRESS", args.email)\
  62         .replace("PROTONAME", args.protoname)\
  63         .replace("PROTOSHORTNAME", args.protoshortname)\
  64         .replace("PROTOABBREV", args.protoabbrev)\
  65         .replace("FIELDNAME", "Sample Field")\
  66         .replace("FIELDABBREV", "sample_field")\
  67         .replace("FT_FIELDTYPE", "FT_STRING")\
  68         .replace("FIELDDISPLAY", "BASE_NONE")\
  69         .replace("FIELDCONVERT", "NULL")\
  70         .replace("BITMASK", "0x0")\
  71         .replace("FIELDDESCR", "NULL")\
  72         .replace("MAX_NEEDED_FOR_HEURISTICS", "1")\
  73         .replace("TEST_HEURISTICS_FAIL", "0")\
  74         .replace("ENC_xxx", "ENC_NA")\
  75         .replace("EXPERTABBREV", "expert")\
  76         .replace("PI_GROUP", "PI_PROTOCOL")\
  77         .replace("PI_SEVERITY", "PI_ERROR")\
  78         .replace("TEST_EXPERT_condition", "0")\
  79         .replace("const char *subtree", "\"\"")\
  80         .replace("LICENSE", args.license)\
  81         .replace("YEARS", args.years)
  82
  83     return output
  84
  85
  86 def write_dissector(buffer, args):
  87     ofile = output_file(args)
  88     if os.path.isfile(ofile) and not args.force:
  89         raise Exception("The file " + ofile + " already exists. You're likely overwriting an existing dissector.")
  90     print("Writing output file: " + ofile)
  91     return open(ofile, "w").write(buffer)
  92
  93
  94 def patch_makefile(args):
  95     if args.plugin:
  96         cmakefile = os.path.join(wsdir(), "CMakeLists.txt")
  97         patchline = "\t\tplugins/epan/" + args.protoabbrev
  98         groupstart = "set(PLUGIN_SRC_DIRS"
  99     else:
 100         cmakefile = os.path.join(wsdir(), "epan/dissectors/CMakeLists.txt")
 101         patchline = "\t${CMAKE_CURRENT_SOURCE_DIR}/packet-" + args.protoabbrev + ".c"
 102         groupstart = "set(DISSECTOR_SRC"
 103     print("Patching makefile: " + cmakefile)
 104     output = ""
 105     in_group = False
 106     patched = False
 107     for line in open(cmakefile):
 108         line_strip = line.strip()
 109         if in_group and line_strip == ")":
 110             in_group = False
 111         if in_group and not patched and line_strip > patchline:
 112             output += patchline + "\n"
 113             patched = True
 114         if line_strip == groupstart:
 115             in_group = True
 116         if line_strip != patchline:
 117             output += line
 118     open(cmakefile, "w").write(output)
 119
 120
 121 def write_plugin_makefile(args):
 122     if not args.plugin:
 123         return True
 124     buffer = replace_fields(read_skeleton("CMakeLists-PROTOABBREV.txt"), args)
 125     ofile = os.path.join(output_dir(args), "CMakeLists.txt")
 126     print("Writing output file: " + ofile)
 127     return open(ofile, "w").write(buffer)
 128
 129
 130 def print_header():
 131     print("")
 132     print("**************************************************")
 133     print("*   Wireshark skeleton dissector generator       *")
 134     print("*                                                *")
 135     print("*   Generate a new dissector for your protocol   *")
 136     print("*   starting from the skeleton provided in the   *")
 137     print("*   doc directory.                               *")
 138     print("*                                                *")
 139     print("*   Copyright 2019 Dario Lombardo                *")
 140     print("**************************************************")
 141     print("")
 142
 143
 144 def print_trailer(args):
 145     print("")
 146     print("The skeleton for the dissector of the " + args.protoshortname + " protocol has been generated.")
 147     print("Please review/extend it to match your specific criteria.")
 148     print("")
 149
 150
 151 if __name__ == '__main__':
 152     print_header()
 153     args = parser.parse_args()
 154     buffer = replace_fields(read_skeleton("packet-PROTOABBREV.c"), args)
 155     write_dissector(buffer, args)
 156     patch_makefile(args)
 157     write_plugin_makefile(args)
 158     print_trailer(args)