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

   1 /* Port-triggering target.
   2  *
   3  * Copyright (C) 2003, CyberTAN Corporation
   4  * All Rights Reserved.
   5  */
   6
   7 /* Shared library add-on to iptables to add port-trigger support. */
   8
   9 #include <stdio.h>
  10 #include <netdb.h>
  11 #include <string.h>
  12 #include <stdlib.h>
  13 #include <getopt.h>
  14 #include <iptables.h>
  15 #include <linux/netfilter_ipv4/ip_tables.h>
  16 #include <linux/netfilter_ipv4/ip_nat_rule.h>
  17 #include <linux/netfilter_ipv4/ipt_TRIGGER.h>
  18
  19 /* Function which prints out usage message. */
  20 static void
  21 help(void)
  22 {
  23         printf(
  24 "TRIGGER v%s options:\n"
  25 " --trigger-type (dnat|in|out)\n"
  26 "                               Trigger type\n"
  27 " --trigger-proto proto\n"
  28 "                               Trigger protocol\n"
  29 " --trigger-match port[-port]\n"
  30 "                               Trigger destination port range\n"
  31 " --trigger-relate port[-port]\n"
  32 "                               Port range to map related destination port range to.\n\n",
  33 IPTABLES_VERSION);
  34 }
  35
  36 static struct option opts[] = {
  37         { "trigger-type", 1, 0, '1' },
  38         { "trigger-proto", 1, 0, '2' },
  39         { "trigger-match", 1, 0, '3' },
  40         { "trigger-relate", 1, 0, '4' },
  41         { 0 }
  42 };
  43
  44 /* Initialize the target. */
  45 static void
  46 init(struct ipt_entry_target *t, unsigned int *nfcache)
  47 {
  48         /* Can't cache this */
  49         *nfcache |= NFC_UNKNOWN;
  50 }
  51
  52 /* Parses ports */
  53 static void
  54 parse_ports(const char *arg, u_int16_t *ports)
  55 {
  56         const char *dash;
  57         int port;
  58
  59         port = atoi(arg);
  60         if (port == 0 || port > 65535)
  61                 exit_error(PARAMETER_PROBLEM, "Port range `%s' invalid\n", arg);
  62
  63         dash = strchr(arg, '-');
  64         if (!dash)
  65                 ports[0] = ports[1] = port;
  66         else {
  67                 int maxport;
  68
  69                 maxport = atoi(dash + 1);
  70                 if (maxport == 0 || maxport > 65535)
  71                         exit_error(PARAMETER_PROBLEM,
  72                                    "Port range `%s' invalid\n", dash+1);
  73                 if (maxport < port)
  74                         exit_error(PARAMETER_PROBLEM,
  75                                    "Port range `%s' invalid\n", arg);
  76                 ports[0] = port;
  77                 ports[1] = maxport;
  78         }
  79 }
  80
  81
  82 /* Function which parses command options; returns true if it
  83    ate an option */
  84 static int
  85 parse(int c, char **argv, int invert, unsigned int *flags,
  86       const struct ipt_entry *entry,
  87       struct ipt_entry_target **target)
  88 {
  89         struct ipt_trigger_info *info = (struct ipt_trigger_info *)(*target)->data;
  90
  91         switch (c) {
  92         case '1':
  93                 if (!strcasecmp(optarg, "dnat"))
  94                         info->type = IPT_TRIGGER_DNAT;
  95                 else if (!strcasecmp(optarg, "in"))
  96                         info->type = IPT_TRIGGER_IN;
  97                 else if (!strcasecmp(optarg, "out"))
  98                         info->type = IPT_TRIGGER_OUT;
  99                 else
 100                         exit_error(PARAMETER_PROBLEM,
 101                                    "unknown type `%s' specified", optarg);
 102                 return 1;
 103
 104         case '2':
 105                 if (!strcasecmp(optarg, "tcp"))
 106                         info->proto = IPPROTO_TCP;
 107                 else if (!strcasecmp(optarg, "udp"))
 108                         info->proto = IPPROTO_UDP;
 109                 else if (!strcasecmp(optarg, "all"))
 110                         info->proto = 0;
 111                 else
 112                         exit_error(PARAMETER_PROBLEM,
 113                                    "unknown protocol `%s' specified", optarg);
 114                 return 1;
 115
 116         case '3':
 117                 if (check_inverse(optarg, &invert, &optind, 0))
 118                         exit_error(PARAMETER_PROBLEM,
 119                                    "Unexpected `!' after --trigger-match");
 120
 121                 parse_ports(optarg, info->ports.mport);
 122                 return 1;
 123
 124         case '4':
 125                 if (check_inverse(optarg, &invert, &optind, 0))
 126                         exit_error(PARAMETER_PROBLEM,
 127                                    "Unexpected `!' after --trigger-relate");
 128
 129                 parse_ports(optarg, info->ports.rport);
 130                 *flags |= IP_NAT_RANGE_PROTO_SPECIFIED;
 131                 return 1;
 132
 133         default:
 134                 return 0;
 135         }
 136 }
 137
 138 /* Final check; don't care. */
 139 static void final_check(unsigned int flags)
 140 {
 141 }
 142
 143 /* Prints out the targinfo. */
 144 static void
 145 print(const struct ipt_ip *ip,
 146       const struct ipt_entry_target *target,
 147       int numeric)
 148 {
 149         struct ipt_trigger_info *info = (struct ipt_trigger_info *)target->data;
 150
 151         printf("TRIGGER ");
 152         if (info->type == IPT_TRIGGER_DNAT)
 153                 printf("type:dnat ");
 154         else if (info->type == IPT_TRIGGER_IN)
 155                 printf("type:in ");
 156         else if (info->type == IPT_TRIGGER_OUT)
 157                 printf("type:out ");
 158
 159         if (info->proto == IPPROTO_TCP)
 160                 printf("tcp ");
 161         else if (info->proto == IPPROTO_UDP)
 162                 printf("udp ");
 163
 164         printf("match:%hu", info->ports.mport[0]);
 165         if (info->ports.mport[1] > info->ports.mport[0])
 166                 printf("-%hu", info->ports.mport[1]);
 167         printf(" ");
 168
 169         printf("relate:%hu", info->ports.rport[0]);
 170         if (info->ports.rport[1] > info->ports.rport[0])
 171                 printf("-%hu", info->ports.rport[1]);
 172         printf(" ");
 173 }
 174
 175 /* Saves the union ipt_targinfo in parsable form to stdout. */
 176 static void
 177 save(const struct ipt_ip *ip, const struct ipt_entry_target *target)
 178 {
 179         struct ipt_trigger_info *info = (struct ipt_trigger_info *)target->data;
 180
 181         printf("--trigger-proto ");
 182         if (info->proto == IPPROTO_TCP)
 183                 printf("tcp ");
 184         else if (info->proto == IPPROTO_UDP)
 185                 printf("udp ");
 186         printf("--trigger-match %hu-%hu ", info->ports.mport[0], info->ports.mport[1]);
 187         printf("--trigger-relate %hu-%hu ", info->ports.rport[0], info->ports.rport[1]);
 188 }
 189
 190 static struct iptables_target trigger = {
 191         .next           = NULL,
 192         .name           = "TRIGGER",
 193         .version        = IPTABLES_VERSION,
 194         .size           = IPT_ALIGN(sizeof(struct ipt_trigger_info)),
 195         .userspacesize  = IPT_ALIGN(sizeof(struct ipt_trigger_info)),
 196         .help           = &help,
 197         .init           = &init,
 198         .parse          = &parse,
 199         .final_check    = &final_check,
 200         .print          = &print,
 201         .save           = &save,
 202         .extra_opts     = opts
 203 };
 204
 205 void _init(void)
 206 {
 207         register_target(&trigger);
 208 }