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
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10 #include <stdbool.h>
  11 #include <getopt.h>
  12 #include <ctype.h>
  13 #include <unistd.h>
  14 #include <sys/fsuid.h>
  15
  16 #include "xmalloc.h"
  17 #include "die.h"
  18 #include "bpf.h"
  19
  20 static const char *short_options = "vhi:Vdbf:p";
  21 static const struct option long_options[] = {
  22         {"input",       required_argument,      NULL, 'i'},
  23         {"format",      required_argument,      NULL, 'f'},
  24         {"cpp",         no_argument,            NULL, 'p'},
  25         {"verbose",     no_argument,            NULL, 'V'},
  26         {"bypass",      no_argument,            NULL, 'b'},
  27         {"dump",        no_argument,            NULL, 'd'},
  28         {"version",     no_argument,            NULL, 'v'},
  29         {"help",        no_argument,            NULL, 'h'},
  30         {NULL, 0, NULL, 0}
  31 };
  32
  33 extern int compile_filter(char *file, int verbose, int bypass, int format,
  34                           bool invoke_cpp);
  35
  36 static void __noreturn help(void)
  37 {
  38         printf("\nbpfc %s, a tiny BPF compiler\n", VERSION_STRING);
  39         puts("http://www.netsniff-ng.org\n\n"
  40              "Usage: bpfc [options] || bpfc <program>\n"
  41              "Options:\n"
  42              "  -i|--input <program/->  Berkeley Packet Filter file/stdin\n"
  43              "  -p|--cpp                Run bpf program through C preprocessor\n"
  44              "  -f|--format <format>    Output format: C|netsniff-ng|xt_bpf|tcpdump\n"
  45              "  -b|--bypass             Bypass filter validation (e.g. for bug testing)\n"
  46              "  -V|--verbose            Be more verbose\n"
  47              "  -d|--dump               Dump supported instruction table\n"
  48              "  -v|--version            Print version and exit\n"
  49              "  -h|--help               Print this help and exit\n\n"
  50              "Examples:\n"
  51              "  bpfc fubar\n"
  52              "  bpfc fubar > foo (bpfc -f C -i fubar > foo) -->  netsniff-ng -f foo ...\n"
  53              "  bpfc -f tcpdump -i fubar > foo -->  tcpdump -ddd like ...\n"
  54              "  bpfc -f xt_bpf -b -p -i fubar\n"
  55              "  iptables -A INPUT -m bpf --bytecode \"`./bpfc -f xt_bpf -i fubar`\" -j LOG\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 __noreturn version(void)
  67 {
  68         printf("\nbpfc %s, a tiny BPF compiler\n", VERSION_LONG);
  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, format = 0;
  82         bool invoke_cpp = false;
  83         char *file = NULL;
  84
  85         setfsuid(getuid());
  86         setfsgid(getgid());
  87
  88         if (argc == 1)
  89                 help();
  90
  91         while ((c = getopt_long(argc, argv, short_options,
  92                                 long_options, &opt_index)) != EOF) {
  93                 switch (c) {
  94                 case 'h':
  95                         help();
  96                         break;
  97                 case 'v':
  98                         version();
  99                         break;
 100                 case 'V':
 101                         verbose = 1;
 102                         break;
 103                 case 'p':
 104                         invoke_cpp = true;
 105                         break;
 106                 case 'f':
 107                         if (!strncmp(optarg, "C", 1) ||
 108                             !strncmp(optarg, "netsniff-ng", 11))
 109                                 format = 0;
 110                         else if (!strncmp(optarg, "xt_bpf", 6))
 111                                 format = 1;
 112                         else if (!strncmp(optarg, "tcpdump", 7))
 113                                 format = 2;
 114                         else
 115                                 help();
 116                         break;
 117                 case 'b':
 118                         bypass = 1;
 119                         break;
 120                 case 'd':
 121                         bpf_dump_op_table();
 122                         die();
 123                 case 'i':
 124                         file = xstrdup(optarg);
 125                         break;
 126                 case '?':
 127                         switch (optopt) {
 128                         case 'i':
 129                         case 'f':
 130                                 panic("Option -%c requires an argument!\n",
 131                                       optopt);
 132                         default:
 133                                 if (isprint(optopt))
 134                                         printf("Unknown option character `0x%X\'!\n", optopt);
 135                                 die();
 136                         }
 137                 default:
 138                         break;
 139                 }
 140         }
 141
 142         if (argc == 2)
 143                 file = xstrdup(argv[1]);
 144         if (!file)
 145                 panic("No Berkeley Packet Filter program specified!\n");
 146
 147         ret = compile_filter(file, verbose, bypass, format, invoke_cpp);
 148
 149         xfree(file);
 150         return ret;
 151 }