src/bpfc.c

   1 /*
   2  * netsniff-ng - the packet sniffing beast
   3  * By Daniel Borkmann <daniel@netsniff-ng.org>
   4  * Copyright 2011 Daniel Borkmann <dborkma@tik.ee.ethz.ch>,
   5  * Swiss federal institute of technology (ETH Zurich)
   6  * Subject to the GPL, version 2.
   7  *
   8  * This is a tiny Berkeley Packet Filter compiler that understands the
   9  * Syntax / Semantic from the USENIX paper {"The BSD Packet Filter: A New
  10  * Architecture for User-level Packet Capture", McCanne, Steven and
  11  * Jacobson, Van, Lawrence Berkeley Laboratory}. With this, BPFs can be
  12  * written the good old way and understood by the Linux kernel and *BSD
  13  * kernels where Berkeley Packet Filters are used.
  14  *
  15  *   The one small garden of a free gardener was all his need and due, not
  16  *   a garden swollen to a realm; his own hands to use, not the hands of
  17  *   others to command.
  18  *
  19  *     -- The Lord of the Rings, Sam, Chapter 'The Tower of Cirith Ungol'.
  20  */
  21
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <getopt.h>
  25 #include <ctype.h>
  26
  27 #include "xmalloc.h"
  28 #include "die.h"
  29
  30 static const char *short_options = "vhi:V";
  31 static const struct option long_options[] = {
  32         {"input",       required_argument,      NULL, 'i'},
  33         {"verbose",     no_argument,            NULL, 'V'},
  34         {"version",     no_argument,            NULL, 'v'},
  35         {"help",        no_argument,            NULL, 'h'},
  36         {NULL, 0, NULL, 0}
  37 };
  38
  39 extern int compile_filter(char *file, int verbose);
  40
  41 static void help(void)
  42 {
  43         printf("\n%s %s, a tiny BPF compiler\n",
  44                PROGNAME_STRING, VERSION_STRING);
  45         puts("http://www.netsniff-ng.org\n\n"
  46              "Usage: bpfc [options] || bpfc <program>\n"
  47              "Options:\n"
  48              "  -i|--input <program>   Berkeley Packet Filter file\n"
  49              "  -V|--verbose           Be more verbose\n"
  50              "  -v|--version           Print version\n"
  51              "  -h|--help              Print this help\n\n"
  52              "Examples:\n"
  53              "  bpfc -i fubar.bpf\n\n"
  54              "Please report bugs to <bugs@netsniff-ng.org>\n"
  55              "Copyright (C) 2011-2012 Daniel Borkmann <dborkma@tik.ee.ethz.ch>,\n"
  56              "Swiss federal institute of technology (ETH Zurich)\n"
  57              "License: GNU GPL version 2.0\n"
  58              "This is free software: you are free to change and redistribute it.\n"
  59              "There is NO WARRANTY, to the extent permitted by law.\n");
  60         die();
  61 }
  62
  63 static void version(void)
  64 {
  65         printf("\n%s %s, a tiny BPF compiler\n",
  66                PROGNAME_STRING, VERSION_STRING);
  67         puts("http://www.netsniff-ng.org\n\n"
  68              "Please report bugs to <bugs@netsniff-ng.org>\n"
  69              "Copyright (C) 2011-2012 Daniel Borkmann <dborkma@tik.ee.ethz.ch>,\n"
  70              "Swiss federal institute of technology (ETH Zurich)\n"
  71              "License: GNU GPL version 2.0\n"
  72              "This is free software: you are free to change and redistribute it.\n"
  73              "There is NO WARRANTY, to the extent permitted by law.\n");
  74         die();
  75 }
  76
  77 int main(int argc, char **argv)
  78 {
  79         int ret, verbose = 0, c, opt_index;
  80         char *file = NULL;
  81
  82         if (argc == 1)
  83                 help();
  84
  85         while (argc > 2 && (c = getopt_long(argc, argv, short_options,
  86                 long_options, &opt_index)) != EOF) {
  87                 switch (c) {
  88                 case 'h':
  89                         help();
  90                         break;
  91                 case 'v':
  92                         version();
  93                         break;
  94                 case 'V':
  95                         verbose = 1;
  96                         break;
  97                 case 'i':
  98                         file = xstrdup(optarg);
  99                         break;
 100                 case '?':
 101                         switch (optopt) {
 102                         case 'i':
 103                                 panic("Option -%c requires an argument!\n",
 104                                       optopt);
 105                         default:
 106                                 if (isprint(optopt))
 107                                         whine("Unknown option character "
 108                                               "`0x%X\'!\n", optopt);
 109                                 die();
 110                         }
 111                 default:
 112                         break;
 113                 }
 114         }
 115         if (argc == 2)
 116                 file = xstrdup(argv[1]);
 117
 118         if (!file)
 119                 panic("No Berkeley Packet Filter program specified!\n");
 120         ret = compile_filter(file, verbose);
 121         xfree(file);
 122         return ret;
 123 }