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 #include "bpf.h"
  30
  31 static const char *short_options = "vhi:Vdb";
  32 static const struct option long_options[] = {
  33         {"input",       required_argument,      NULL, 'i'},
  34         {"verbose",     no_argument,            NULL, 'V'},
  35         {"bypass",      no_argument,            NULL, 'b'},
  36         {"dump",        no_argument,            NULL, 'd'},
  37         {"version",     no_argument,            NULL, 'v'},
  38         {"help",        no_argument,            NULL, 'h'},
  39         {NULL, 0, NULL, 0}
  40 };
  41
  42 extern int compile_filter(char *file, int verbose, int bypass);
  43
  44 static void help(void)
  45 {
  46         printf("\n%s %s, a tiny BPF compiler\n",
  47                PROGNAME_STRING, VERSION_STRING);
  48         puts("http://www.netsniff-ng.org\n\n"
  49              "Usage: bpfc [options] || bpfc <program>\n"
  50              "Options:\n"
  51              "  -i|--input <program>   Berkeley Packet Filter file\n"
  52              "  -V|--verbose           Be more verbose\n"
  53              "  -b|--bypass            Bypass filter validation (e.g. for bug testing)\n"
  54              "  -d|--dump              Dump supported instruction table\n"
  55              "  -v|--version           Print version\n"
  56              "  -h|--help              Print this help\n\n"
  57              "Examples:\n"
  58              "  bpfc -i fubar.bpf\n\n"
  59              "Please report bugs to <bugs@netsniff-ng.org>\n"
  60              "Copyright (C) 2011-2012 Daniel Borkmann <dborkma@tik.ee.ethz.ch>,\n"
  61              "Swiss federal institute of technology (ETH Zurich)\n"
  62              "License: GNU GPL version 2.0\n"
  63              "This is free software: you are free to change and redistribute it.\n"
  64              "There is NO WARRANTY, to the extent permitted by law.\n");
  65         die();
  66 }
  67
  68 static void version(void)
  69 {
  70         printf("\n%s %s, a tiny BPF compiler\n",
  71                PROGNAME_STRING, VERSION_STRING);
  72         puts("http://www.netsniff-ng.org\n\n"
  73              "Please report bugs to <bugs@netsniff-ng.org>\n"
  74              "Copyright (C) 2011-2012 Daniel Borkmann <dborkma@tik.ee.ethz.ch>,\n"
  75              "Swiss federal institute of technology (ETH Zurich)\n"
  76              "License: GNU GPL version 2.0\n"
  77              "This is free software: you are free to change and redistribute it.\n"
  78              "There is NO WARRANTY, to the extent permitted by law.\n");
  79         die();
  80 }
  81
  82 int main(int argc, char **argv)
  83 {
  84         int ret, verbose = 0, c, opt_index, bypass = 0;
  85         char *file = NULL;
  86
  87         if (argc == 1)
  88                 help();
  89
  90         while ((c = getopt_long(argc, argv, short_options,
  91                                 long_options, &opt_index)) != EOF) {
  92                 switch (c) {
  93                 case 'h':
  94                         help();
  95                         break;
  96                 case 'v':
  97                         version();
  98                         break;
  99                 case 'V':
 100                         verbose = 1;
 101                         break;
 102                 case 'b':
 103                         bypass = 1;
 104                         break;
 105                 case 'd':
 106                         bpf_dump_op_table();
 107                         die();
 108                 case 'i':
 109                         file = xstrdup(optarg);
 110                         break;
 111                 case '?':
 112                         switch (optopt) {
 113                         case 'i':
 114                                 panic("Option -%c requires an argument!\n",
 115                                       optopt);
 116                         default:
 117                                 if (isprint(optopt))
 118                                         whine("Unknown option character "
 119                                               "`0x%X\'!\n", optopt);
 120                                 die();
 121                         }
 122                 default:
 123                         break;
 124                 }
 125         }
 126         if (argc == 2)
 127                 file = xstrdup(argv[1]);
 128
 129         if (!file)
 130                 panic("No Berkeley Packet Filter program specified!\n");
 131
 132         ret = compile_filter(file, verbose, bypass);
 133
 134         xfree(file);
 135         return ret;
 136 }