extensions/libxt_tos.c

   1 /*
   2  * Shared library add-on to iptables to add tos match support
   3  *
   4  * Copyright © CC Computer Consultants GmbH, 2007
   5  * Contact: Jan Engelhardt <jengelh@computergmbh.de>
   6  */
   7 #include <getopt.h>
   8 #include <netdb.h>
   9 #include <stdbool.h>
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <string.h>
  13
  14 #include <xtables.h>
  15 #include <linux/netfilter/xt_dscp.h>
  16 #include <linux/netfilter_ipv4/ipt_tos.h>
  17 #include "tos_values.c"
  18
  19 enum {
  20         FLAG_TOS = 1 << 0,
  21 };
  22
  23 static const struct option tos_mt_opts[] = {
  24         {.name = "tos", .has_arg = true, .val = 't'},
  25         { .name = NULL }
  26 };
  27
  28 static void tos_mt_help(void)
  29 {
  30         const struct tos_symbol_info *symbol;
  31
  32         printf(
  33 "tos match options:\n"
  34 "[!] --tos value[/mask]    Match Type of Service/Priority field value\n"
  35 "[!] --tos symbol          Match TOS field (IPv4 only) by symbol\n"
  36 "                          Accepted symbolic names for value are:\n");
  37
  38         for (symbol = tos_symbol_names; symbol->name != NULL; ++symbol)
  39                 printf("                          (0x%02x) %2u %s\n",
  40                        symbol->value, symbol->value, symbol->name);
  41
  42         printf("\n");
  43 }
  44
  45 static int tos_mt_parse_v0(int c, char **argv, int invert, unsigned int *flags,
  46                            const void *entry, struct xt_entry_match **match)
  47 {
  48         struct ipt_tos_info *info = (void *)(*match)->data;
  49         struct tos_value_mask tvm;
  50
  51         switch (c) {
  52         case 't':
  53                 param_act(P_ONLY_ONCE, "tos", "--tos", *flags & FLAG_TOS);
  54                 if (!tos_parse_symbolic(optarg, &tvm, 0xFF))
  55                         param_act(P_BAD_VALUE, "tos", "--tos", optarg);
  56                 if (tvm.mask != 0xFF)
  57                         exit_error(PARAMETER_PROBLEM, "tos: Your kernel is "
  58                                    "too old to support anything besides /0xFF "
  59                                    "as a mask.");
  60                 info->tos = tvm.value;
  61                 if (invert)
  62                         info->invert = true;
  63                 *flags |= FLAG_TOS;
  64                 return true;
  65         }
  66         return false;
  67 }
  68
  69 static int tos_mt_parse(int c, char **argv, int invert, unsigned int *flags,
  70                         const void *entry, struct xt_entry_match **match)
  71 {
  72         struct xt_tos_match_info *info = (void *)(*match)->data;
  73         struct tos_value_mask tvm = {.mask = 0xFF};
  74
  75         switch (c) {
  76         case 't':
  77                 param_act(P_ONLY_ONCE, "tos", "--tos", *flags & FLAG_TOS);
  78                 if (!tos_parse_symbolic(optarg, &tvm, 0x3F))
  79                         param_act(P_BAD_VALUE, "tos", "--tos", optarg);
  80                 info->tos_value = tvm.value;
  81                 info->tos_mask  = tvm.mask;
  82                 if (invert)
  83                         info->invert = true;
  84                 *flags |= FLAG_TOS;
  85                 return true;
  86         }
  87         return false;
  88 }
  89
  90 static void tos_mt_check(unsigned int flags)
  91 {
  92         if (flags == 0)
  93                 exit_error(PARAMETER_PROBLEM,
  94                            "tos: --tos parameter required");
  95 }
  96
  97 static void tos_mt_print_v0(const void *ip, const struct xt_entry_match *match,
  98                             int numeric)
  99 {
 100         const struct ipt_tos_info *info = (const void *)match->data;
 101
 102         printf("tos match ");
 103         if (info->invert)
 104                 printf("!");
 105         if (numeric || !tos_try_print_symbolic("", info->tos, 0x3F))
 106                 printf("0x%02x ", info->tos);
 107 }
 108
 109 static void tos_mt_print(const void *ip, const struct xt_entry_match *match,
 110                          int numeric)
 111 {
 112         const struct xt_tos_match_info *info = (const void *)match->data;
 113
 114         printf("tos match ");
 115         if (info->invert)
 116                 printf("!");
 117         if (numeric ||
 118             !tos_try_print_symbolic("", info->tos_value, info->tos_mask))
 119                 printf("0x%02x/0x%02x ", info->tos_value, info->tos_mask);
 120 }
 121
 122 static void tos_mt_save_v0(const void *ip, const struct xt_entry_match *match)
 123 {
 124         const struct ipt_tos_info *info = (const void *)match->data;
 125
 126         if (info->invert)
 127                 printf("! ");
 128         printf("--tos 0x%02x ", info->tos);
 129 }
 130
 131 static void tos_mt_save(const void *ip, const struct xt_entry_match *match)
 132 {
 133         const struct xt_tos_match_info *info = (const void *)match->data;
 134
 135         if (info->invert)
 136                 printf("! ");
 137         printf("--tos 0x%02x/0x%02x ", info->tos_value, info->tos_mask);
 138 }
 139
 140 static struct xtables_match tos_mt_reg_v0 = {
 141         .version       = XTABLES_VERSION,
 142         .name          = "tos",
 143         .family        = AF_INET,
 144         .revision      = 0,
 145         .size          = XT_ALIGN(sizeof(struct ipt_tos_info)),
 146         .userspacesize = XT_ALIGN(sizeof(struct ipt_tos_info)),
 147         .help          = tos_mt_help,
 148         .parse         = tos_mt_parse_v0,
 149         .final_check   = tos_mt_check,
 150         .print         = tos_mt_print_v0,
 151         .save          = tos_mt_save_v0,
 152         .extra_opts    = tos_mt_opts,
 153 };
 154
 155 static struct xtables_match tos_mt_reg = {
 156         .version       = XTABLES_VERSION,
 157         .name          = "tos",
 158         .family        = AF_INET,
 159         .revision      = 1,
 160         .size          = XT_ALIGN(sizeof(struct xt_tos_match_info)),
 161         .userspacesize = XT_ALIGN(sizeof(struct xt_tos_match_info)),
 162         .help          = tos_mt_help,
 163         .parse         = tos_mt_parse,
 164         .final_check   = tos_mt_check,
 165         .print         = tos_mt_print,
 166         .save          = tos_mt_save,
 167         .extra_opts    = tos_mt_opts,
 168 };
 169
 170 static struct xtables_match tos_mt6_reg = {
 171         .version       = XTABLES_VERSION,
 172         .name          = "tos",
 173         .family        = AF_INET6,
 174         .revision      = 1,
 175         .size          = XT_ALIGN(sizeof(struct xt_tos_match_info)),
 176         .userspacesize = XT_ALIGN(sizeof(struct xt_tos_match_info)),
 177         .help          = tos_mt_help,
 178         .parse         = tos_mt_parse,
 179         .final_check   = tos_mt_check,
 180         .print         = tos_mt_print,
 181         .save          = tos_mt_save,
 182         .extra_opts    = tos_mt_opts,
 183 };
 184
 185 void _init(void)
 186 {
 187         xtables_register_match(&tos_mt_reg_v0);
 188         xtables_register_match(&tos_mt_reg);
 189         xtables_register_match(&tos_mt6_reg);
 190 }