user/iptables/extensions/libipt_ECN.c

   1 /* Shared library add-on to iptables for ECN, $Version$
   2  *
   3  * (C) 2002 by Harald Welte <laforge@gnumonks.org>
   4  *
   5  * This program is distributed under the terms of GNU GPL v2, 1991
   6  *
   7  * libipt_ECN.c borrowed heavily from libipt_DSCP.c
   8  *
   9  * $Id$
  10  */
  11 #include <stdio.h>
  12 #include <string.h>
  13 #include <stdlib.h>
  14 #include <getopt.h>
  15
  16 #include <xtables.h>
  17 #include <linux/netfilter_ipv4/ipt_ECN.h>
  18
  19 static void ECN_help(void)
  20 {
  21         printf(
  22 "ECN target options\n"
  23 "  --ecn-tcp-remove             Remove all ECN bits from TCP header\n");
  24 }
  25
  26 #if 0
  27 "ECN target v%s EXPERIMENTAL options (use with extreme care!)\n"
  28 "  --ecn-ip-ect                 Set the IPv4 ECT codepoint (0 to 3)\n"
  29 "  --ecn-tcp-cwr                Set the IPv4 CWR bit (0 or 1)\n"
  30 "  --ecn-tcp-ece                Set the IPv4 ECE bit (0 or 1)\n",
  31 #endif
  32
  33
  34 static const struct option ECN_opts[] = {
  35         { "ecn-tcp-remove", 0, NULL, 'F' },
  36         { "ecn-tcp-cwr", 1, NULL, 'G' },
  37         { "ecn-tcp-ece", 1, NULL, 'H' },
  38         { "ecn-ip-ect", 1, NULL, '9' },
  39         { .name = NULL }
  40 };
  41
  42 static int ECN_parse(int c, char **argv, int invert, unsigned int *flags,
  43                      const void *entry, struct xt_entry_target **target)
  44 {
  45         unsigned int result;
  46         struct ipt_ECN_info *einfo
  47                 = (struct ipt_ECN_info *)(*target)->data;
  48
  49         switch (c) {
  50         case 'F':
  51                 if (*flags)
  52                         xtables_error(PARAMETER_PROBLEM,
  53                                 "ECN target: Only use --ecn-tcp-remove ONCE!");
  54                 einfo->operation = IPT_ECN_OP_SET_ECE | IPT_ECN_OP_SET_CWR;
  55                 einfo->proto.tcp.ece = 0;
  56                 einfo->proto.tcp.cwr = 0;
  57                 *flags = 1;
  58                 break;
  59         case 'G':
  60                 if (*flags & IPT_ECN_OP_SET_CWR)
  61                         xtables_error(PARAMETER_PROBLEM,
  62                                 "ECN target: Only use --ecn-tcp-cwr ONCE!");
  63                 if (!xtables_strtoui(optarg, NULL, &result, 0, 1))
  64                         xtables_error(PARAMETER_PROBLEM,
  65                                    "ECN target: Value out of range");
  66                 einfo->operation |= IPT_ECN_OP_SET_CWR;
  67                 einfo->proto.tcp.cwr = result;
  68                 *flags |= IPT_ECN_OP_SET_CWR;
  69                 break;
  70         case 'H':
  71                 if (*flags & IPT_ECN_OP_SET_ECE)
  72                         xtables_error(PARAMETER_PROBLEM,
  73                                 "ECN target: Only use --ecn-tcp-ece ONCE!");
  74                 if (!xtables_strtoui(optarg, NULL, &result, 0, 1))
  75                         xtables_error(PARAMETER_PROBLEM,
  76                                    "ECN target: Value out of range");
  77                 einfo->operation |= IPT_ECN_OP_SET_ECE;
  78                 einfo->proto.tcp.ece = result;
  79                 *flags |= IPT_ECN_OP_SET_ECE;
  80                 break;
  81         case '9':
  82                 if (*flags & IPT_ECN_OP_SET_IP)
  83                         xtables_error(PARAMETER_PROBLEM,
  84                                 "ECN target: Only use --ecn-ip-ect ONCE!");
  85                 if (!xtables_strtoui(optarg, NULL, &result, 0, 3))
  86                         xtables_error(PARAMETER_PROBLEM,
  87                                    "ECN target: Value out of range");
  88                 einfo->operation |= IPT_ECN_OP_SET_IP;
  89                 einfo->ip_ect = result;
  90                 *flags |= IPT_ECN_OP_SET_IP;
  91                 break;
  92         default:
  93                 return 0;
  94         }
  95
  96         return 1;
  97 }
  98
  99 static void ECN_check(unsigned int flags)
 100 {
 101         if (!flags)
 102                 xtables_error(PARAMETER_PROBLEM,
 103                            "ECN target: Parameter --ecn-tcp-remove is required");
 104 }
 105
 106 static void ECN_print(const void *ip, const struct xt_entry_target *target,
 107                       int numeric)
 108 {
 109         const struct ipt_ECN_info *einfo =
 110                 (const struct ipt_ECN_info *)target->data;
 111
 112         printf("ECN ");
 113
 114         if (einfo->operation == (IPT_ECN_OP_SET_ECE|IPT_ECN_OP_SET_CWR)
 115             && einfo->proto.tcp.ece == 0
 116             && einfo->proto.tcp.cwr == 0)
 117                 printf("TCP remove ");
 118         else {
 119                 if (einfo->operation & IPT_ECN_OP_SET_ECE)
 120                         printf("ECE=%u ", einfo->proto.tcp.ece);
 121
 122                 if (einfo->operation & IPT_ECN_OP_SET_CWR)
 123                         printf("CWR=%u ", einfo->proto.tcp.cwr);
 124
 125                 if (einfo->operation & IPT_ECN_OP_SET_IP)
 126                         printf("ECT codepoint=%u ", einfo->ip_ect);
 127         }
 128 }
 129
 130 static void ECN_save(const void *ip, const struct xt_entry_target *target)
 131 {
 132         const struct ipt_ECN_info *einfo =
 133                 (const struct ipt_ECN_info *)target->data;
 134
 135         if (einfo->operation == (IPT_ECN_OP_SET_ECE|IPT_ECN_OP_SET_CWR)
 136             && einfo->proto.tcp.ece == 0
 137             && einfo->proto.tcp.cwr == 0)
 138                 printf("--ecn-tcp-remove ");
 139         else {
 140
 141                 if (einfo->operation & IPT_ECN_OP_SET_ECE)
 142                         printf("--ecn-tcp-ece %d ", einfo->proto.tcp.ece);
 143
 144                 if (einfo->operation & IPT_ECN_OP_SET_CWR)
 145                         printf("--ecn-tcp-cwr %d ", einfo->proto.tcp.cwr);
 146
 147                 if (einfo->operation & IPT_ECN_OP_SET_IP)
 148                         printf("--ecn-ip-ect %d ", einfo->ip_ect);
 149         }
 150 }
 151
 152 static struct xtables_target ecn_tg_reg = {
 153         .name           = "ECN",
 154         .version        = XTABLES_VERSION,
 155         .family         = NFPROTO_IPV4,
 156         .size           = XT_ALIGN(sizeof(struct ipt_ECN_info)),
 157         .userspacesize  = XT_ALIGN(sizeof(struct ipt_ECN_info)),
 158         .help           = ECN_help,
 159         .parse          = ECN_parse,
 160         .final_check    = ECN_check,
 161         .print          = ECN_print,
 162         .save           = ECN_save,
 163         .extra_opts     = ECN_opts,
 164 };
 165
 166 void _init(void)
 167 {
 168         xtables_register_target(&ecn_tg_reg);
 169 }