release/src/router/iptables/extensions/libipt_osf.c

   1 /*
   2  * libipt_osf.c
   3  *
   4  * Copyright (c) 2003 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
   5  *
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  20  */
  21
  22 /*
  23  * iptables interface for OS fingerprint matching module.
  24  */
  25
  26 #include <stdio.h>
  27 #include <netdb.h>
  28 #include <string.h>
  29 #include <stdlib.h>
  30 #include <getopt.h>
  31 #include <ctype.h>
  32
  33 #include <iptables.h>
  34 #include <linux/netfilter_ipv4/ipt_osf.h>
  35
  36 static void help(void)
  37 {
  38         printf("OS fingerprint match options:\n"
  39                 "--genre [!] string     Match a OS genre by passive fingerprinting.\n"
  40                 "--smart                Use some smart extensions to determine OS (do not use TTL).\n"
  41                 "--log level            Log all(or only first) determined genres even if "
  42                                         "they do not match desired one. "
  43                                         "Level may be 0(all) or 1(only first entry).\n"
  44                 "--netlink              Log through netlink(NETLINK_NFLOG).\n",
  45                 "--connector            Log through kernel connector [in 2.6.12-mm+].\n"
  46                 );
  47 }
  48
  49
  50 static struct option opts[] = {
  51         { .name = "genre",      .has_arg = 1, .flag = 0, .val = '1' },
  52         { .name = "smart",      .has_arg = 0, .flag = 0, .val = '2' },
  53         { .name = "log",        .has_arg = 1, .flag = 0, .val = '3' },
  54         { .name = "netlink",    .has_arg = 0, .flag = 0, .val = '4' },
  55         { .name = "connector",  .has_arg = 0, .flag = 0, .val = '5' },
  56         { .name = 0 }
  57 };
  58
  59 static void parse_string(const unsigned char *s, struct ipt_osf_info *info)
  60 {
  61         if (strlen(s) < MAXGENRELEN)
  62                 strcpy(info->genre, s);
  63         else
  64                 exit_error(PARAMETER_PROBLEM, "Genre string too long `%s' [%d], max=%d",
  65                                 s, strlen(s), MAXGENRELEN);
  66 }
  67
  68 static int parse(int c, char **argv, int invert, unsigned int *flags,
  69                         const struct ipt_entry *entry,
  70                         unsigned int *nfcache,
  71                         struct ipt_entry_match **match)
  72 {
  73         struct ipt_osf_info *info = (struct ipt_osf_info *)(*match)->data;
  74
  75         switch(c)
  76         {
  77                 case '1': /* --genre */
  78                         if (*flags & IPT_OSF_GENRE)
  79                                 exit_error(PARAMETER_PROBLEM, "Can't specify multiple genre parameter");
  80                         check_inverse(optarg, &invert, &optind, 0);
  81                         parse_string(argv[optind-1], info);
  82                         if (invert)
  83                                 info->invert = 1;
  84                         info->len=strlen((char *)info->genre);
  85                         *flags |= IPT_OSF_GENRE;
  86                         break;
  87                 case '2': /* --smart */
  88                         if (*flags & IPT_OSF_SMART)
  89                                 exit_error(PARAMETER_PROBLEM, "Can't specify multiple smart parameter");
  90                         *flags |= IPT_OSF_SMART;
  91                         info->flags |= IPT_OSF_SMART;
  92                         break;
  93                 case '3': /* --log */
  94                         if (*flags & IPT_OSF_LOG)
  95                                 exit_error(PARAMETER_PROBLEM, "Can't specify multiple log parameter");
  96                         *flags |= IPT_OSF_LOG;
  97                         info->loglevel = atoi(argv[optind-1]);
  98                         info->flags |= IPT_OSF_LOG;
  99                         break;
 100                 case '4': /* --netlink */
 101                         if (*flags & IPT_OSF_NETLINK)
 102                                 exit_error(PARAMETER_PROBLEM, "Can't specify multiple netlink parameter");
 103                         *flags |= IPT_OSF_NETLINK;
 104                         info->flags |= IPT_OSF_NETLINK;
 105                         break;
 106                 case '5': /* --connector */
 107                         if (*flags & IPT_OSF_CONNECTOR)
 108                                 exit_error(PARAMETER_PROBLEM, "Can't specify multiple connector parameter");
 109                         *flags |= IPT_OSF_CONNECTOR;
 110                         info->flags |= IPT_OSF_CONNECTOR;
 111                         break;
 112                 default:
 113                         return 0;
 114         }
 115
 116         return 1;
 117 }
 118
 119 static void final_check(unsigned int flags)
 120 {
 121         if (!flags)
 122                 exit_error(PARAMETER_PROBLEM, "OS fingerprint match: You must specify `--genre'");
 123 }
 124
 125 static void print(const struct ipt_ip *ip, const struct ipt_entry_match *match, int numeric)
 126 {
 127         const struct ipt_osf_info *info = (const struct ipt_osf_info*) match->data;
 128
 129         printf("OS fingerprint match %s%s ", (info->invert) ? "!" : "", info->genre);
 130 }
 131
 132 static void save(const struct ipt_ip *ip, const struct ipt_entry_match *match)
 133 {
 134         const struct ipt_osf_info *info = (const struct ipt_osf_info*) match->data;
 135
 136         printf("--genre %s%s ", (info->invert) ? "! ": "", info->genre);
 137        if (info->flags & IPT_OSF_SMART)
 138                printf("--smart ");
 139        if (info->flags & IPT_OSF_LOG)
 140                printf("--log %d ", info->loglevel);
 141        if (info->flags & IPT_OSF_NETLINK)
 142                printf("--netlink ");
 143        if (info->flags & IPT_OSF_CONNECTOR)
 144                printf("--connector ");
 145 }
 146
 147
 148 static struct iptables_match osf_match = {
 149     .name          = "osf",
 150     .version       = IPTABLES_VERSION,
 151     .size          = IPT_ALIGN(sizeof(struct ipt_osf_info)),
 152     .userspacesize = IPT_ALIGN(sizeof(struct ipt_osf_info)),
 153     .help          = &help,
 154     .parse         = &parse,
 155     .final_check   = &final_check,
 156     .print         = &print,
 157     .save          = &save,
 158     .extra_opts    = opts
 159 };
 160
 161
 162 void _init(void)
 163 {
 164         register_match(&osf_match);
 165 }