bpfc.c

   1 /*
   2  * netsniff-ng - the packet sniffing beast
   3  * Copyright 2011 Daniel Borkmann <dborkma@tik.ee.ethz.ch>,
   4  * Swiss federal institute of technology (ETH Zurich)
   5  * Subject to the GPL, version 2.
   6  *
   7  *   The one small garden of a free gardener was all his need and due, not
   8  *   a garden swollen to a realm; his own hands to use, not the hands of
   9  *   others to command.
  10  *
  11  *     -- The Lord of the Rings, Sam, Chapter 'The Tower of Cirith Ungol'.
  12  */
  13
  14 #include <stdio.h>
  15 #include <stdlib.h>
  16 #include <getopt.h>
  17 #include <ctype.h>
  18 #include <unistd.h>
  19 #include <sys/fsuid.h>
  20
  21 #include "xmalloc.h"
  22 #include "xutils.h"
  23 #include "die.h"
  24 #include "bpf.h"
  25
  26 static const char *short_options = "vhi:VdbD";
  27 static const struct option long_options[] = {
  28         {"input",       required_argument,      NULL, 'i'},
  29         {"verbose",     no_argument,            NULL, 'V'},
  30         {"decimal",     no_argument,            NULL, 'D'},
  31         {"bypass",      no_argument,            NULL, 'b'},
  32         {"dump",        no_argument,            NULL, 'd'},
  33         {"version",     no_argument,            NULL, 'v'},
  34         {"help",        no_argument,            NULL, 'h'},
  35         {NULL, 0, NULL, 0}
  36 };
  37
  38 extern int compile_filter(char *file, int verbose, int bypass, int decimal);
  39
  40 static void help(void)
  41 {
  42         printf("\nbpfc %s, a tiny BPF compiler\n", VERSION_STRING);
  43         puts("http://www.netsniff-ng.org\n\n"
  44              "Usage: bpfc [options] || bpfc <program>\n"
  45              "Options:\n"
  46              "  -i|--input <program/->  Berkeley Packet Filter file/stdin\n"
  47              "  -D|--decimal            Decimal output, e.g. for xt_bpf\n"
  48              "  -V|--verbose            Be more verbose\n"
  49              "  -b|--bypass             Bypass filter validation (e.g. for bug testing)\n"
  50              "  -d|--dump               Dump supported instruction table\n"
  51              "  -v|--version            Print version\n"
  52              "  -h|--help               Print this help\n\n"
  53              "Examples:\n"
  54              "  bpfc fubar\n"
  55              "  bpfc -Dbi fubar\n"
  56              "  bpfc -   (read from stdin)\n\n"
  57              "Please report bugs to <bugs@netsniff-ng.org>\n"
  58              "Copyright (C) 2011-2013 Daniel Borkmann <dborkma@tik.ee.ethz.ch>,\n"
  59              "Swiss federal institute of technology (ETH Zurich)\n"
  60              "License: GNU GPL version 2.0\n"
  61              "This is free software: you are free to change and redistribute it.\n"
  62              "There is NO WARRANTY, to the extent permitted by law.\n");
  63         die();
  64 }
  65
  66 static void version(void)
  67 {
  68         printf("\nbpfc %s, a tiny BPF compiler\n", VERSION_STRING);
  69         puts("http://www.netsniff-ng.org\n\n"
  70              "Please report bugs to <bugs@netsniff-ng.org>\n"
  71              "Copyright (C) 2011-2013 Daniel Borkmann <dborkma@tik.ee.ethz.ch>,\n"
  72              "Swiss federal institute of technology (ETH Zurich)\n"
  73              "License: GNU GPL version 2.0\n"
  74              "This is free software: you are free to change and redistribute it.\n"
  75              "There is NO WARRANTY, to the extent permitted by law.\n");
  76         die();
  77 }
  78
  79 int main(int argc, char **argv)
  80 {
  81         int ret, verbose = 0, c, opt_index, bypass = 0, decimal = 0;
  82         char *file = NULL;
  83
  84         setfsuid(getuid());
  85         setfsgid(getgid());
  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 'D':
 103                         decimal = 1;
 104                         break;
 105                 case 'b':
 106                         bypass = 1;
 107                         break;
 108                 case 'd':
 109                         bpf_dump_op_table();
 110                         die();
 111                 case 'i':
 112                         file = xstrdup(optarg);
 113                         break;
 114                 case '?':
 115                         switch (optopt) {
 116                         case 'i':
 117                                 panic("Option -%c requires an argument!\n",
 118                                       optopt);
 119                         default:
 120                                 if (isprint(optopt))
 121                                         printf("Unknown option character `0x%X\'!\n", optopt);
 122                                 die();
 123                         }
 124                 default:
 125                         break;
 126                 }
 127         }
 128
 129         if (argc == 2)
 130                 file = xstrdup(argv[1]);
 131         if (!file)
 132                 panic("No Berkeley Packet Filter program specified!\n");
 133
 134         ret = compile_filter(file, verbose, bypass, decimal);
 135
 136         xfree(file);
 137         return ret;
 138 }