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

   1 /*
   2  * Automatic port forwarding target. When this target is entered, a
   3  * related connection to a port in the reply direction will be
   4  * expected. This connection may be mapped to a different port.
   5  *
   6  * Copyright 2005, Broadcom Corporation
   7  * All Rights Reserved.
   8  *
   9  * THIS SOFTWARE IS OFFERED "AS IS", AND BROADCOM GRANTS NO WARRANTIES OF ANY
  10  * KIND, EXPRESS OR IMPLIED, BY STATUTE, COMMUNICATION OR OTHERWISE. BROADCOM
  11  * SPECIFICALLY DISCLAIMS ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS
  12  * FOR A SPECIFIC PURPOSE OR NONINFRINGEMENT CONCERNING THIS SOFTWARE.
  13  *
  14  * $Id: libipt_autofw.c,v 1.1.1.7 2005/03/07 07:31:14 kanki Exp $
  15  */
  16
  17 /* Shared library add-on to iptables to add masquerade support. */
  18 #include <stdio.h>
  19 #include <netdb.h>
  20 #include <string.h>
  21 #include <stdlib.h>
  22 #include <getopt.h>
  23 #include <iptables.h>
  24 #include <linux/netfilter_ipv4/ip_tables.h>
  25 #include <linux/netfilter_ipv4/ip_nat_rule.h>
  26 #include <linux/netfilter_ipv4/ip_autofw.h>
  27
  28 /* Function which prints out usage message. */
  29 static void
  30 help(void)
  31 {
  32         printf(
  33 "autofw v%s options:\n"
  34 " --related-proto proto\n"
  35 "                               Related protocol\n"
  36 " --related-dport port[-port]\n"
  37 "                               Related destination port range\n"
  38 " --related-to port[-port]\n"
  39 "                               Port range to map related destination port range to.\n\n",
  40 IPTABLES_VERSION);
  41 }
  42
  43 static struct option opts[] = {
  44         { "related-proto", 1, 0, '1' },
  45         { "related-dport", 1, 0, '2' },
  46         { "related-to", 1, 0, '3' },
  47         { 0 }
  48 };
  49
  50 /* Initialize the target. */
  51 static void
  52 init(struct ipt_entry_target *t, unsigned int *nfcache)
  53 {
  54         /* Can't cache this */
  55         *nfcache |= NFC_UNKNOWN;
  56 }
  57
  58 /* Parses ports */
  59 static void
  60 parse_ports(const char *arg, u_int16_t *ports)
  61 {
  62         const char *dash;
  63         int port;
  64
  65         port = atoi(arg);
  66         if (port == 0 || port > 65535)
  67                 exit_error(PARAMETER_PROBLEM, "Port `%s' not valid\n", arg);
  68
  69         dash = strchr(arg, '-');
  70         if (!dash)
  71                 ports[0] = ports[1] = htons(port);
  72         else {
  73                 int maxport;
  74
  75                 maxport = atoi(dash + 1);
  76                 if (maxport == 0 || maxport > 65535)
  77                         exit_error(PARAMETER_PROBLEM,
  78                                    "Port `%s' not valid\n", dash+1);
  79                 if (maxport < port)
  80                         /* People are stupid. */
  81                         exit_error(PARAMETER_PROBLEM,
  82                                    "Port range `%s' funky\n", arg);
  83                 ports[0] = htons(port);
  84                 ports[1] = htons(maxport);
  85         }
  86 }
  87
  88
  89 /* Function which parses command options; returns true if it
  90    ate an option */
  91 static int
  92 parse(int c, char **argv, int invert, unsigned int *flags,
  93       const struct ipt_entry *entry,
  94       struct ipt_entry_target **target)
  95 {
  96         struct ip_autofw_info *info = (struct ip_autofw_info *)(*target)->data;
  97
  98         switch (c) {
  99         case '1':
 100                 if (!strcasecmp(optarg, "tcp"))
 101                         info->proto = IPPROTO_TCP;
 102                 else if (!strcasecmp(optarg, "udp"))
 103                         info->proto = IPPROTO_UDP;
 104                 else
 105                         exit_error(PARAMETER_PROBLEM,
 106                                    "unknown protocol `%s' specified", optarg);
 107                 return 1;
 108
 109         case '2':
 110                 if (check_inverse(optarg, &invert, &optind, 0))
 111                         exit_error(PARAMETER_PROBLEM,
 112                                    "Unexpected `!' after --related-dport");
 113
 114                 parse_ports(optarg, info->dport);
 115                 return 1;
 116
 117         case '3':
 118                 if (check_inverse(optarg, &invert, &optind, 0))
 119                         exit_error(PARAMETER_PROBLEM,
 120                                    "Unexpected `!' after --related-to");
 121
 122                 parse_ports(optarg, info->to);
 123                 *flags |= IP_NAT_RANGE_PROTO_SPECIFIED;
 124                 return 1;
 125
 126         default:
 127                 return 0;
 128         }
 129 }
 130
 131 /* Final check; don't care. */
 132 static void final_check(unsigned int flags)
 133 {
 134 }
 135
 136 /* Prints out the targinfo. */
 137 static void
 138 print(const struct ipt_ip *ip,
 139       const struct ipt_entry_target *target,
 140       int numeric)
 141 {
 142         struct ip_autofw_info *info = (struct ip_autofw_info *)target->data;
 143
 144         printf("autofw ");
 145         if (info->proto == IPPROTO_TCP)
 146                 printf("tcp ");
 147         else if (info->proto == IPPROTO_UDP)
 148                 printf("udp ");
 149         printf("dpt:%hu", ntohs(info->dport[0]));
 150         if (ntohs(info->dport[1]) > ntohs(info->dport[0]))
 151                 printf("-%hu", ntohs(info->dport[1]));
 152         printf(" ");
 153         printf("to:%hu", ntohs(info->to[0]));
 154         if (ntohs(info->to[1]) > ntohs(info->to[0]))
 155                 printf("-%hu", ntohs(info->to[1]));
 156         printf(" ");
 157 }
 158
 159 /* Saves the union ipt_targinfo in parsable form to stdout. */
 160 static void
 161 save(const struct ipt_ip *ip, const struct ipt_entry_target *target)
 162 {
 163         struct ip_autofw_info *info = (struct ip_autofw_info *)target->data;
 164
 165         printf("--related-proto ");
 166         if (info->proto == IPPROTO_TCP)
 167                 printf("tcp ");
 168         else if (info->proto == IPPROTO_UDP)
 169                 printf("udp ");
 170         printf("--related-dport %hu-%hu ", ntohs(info->dport[0]), ntohs(info->dport[1]));
 171         printf("--related-to %hu-%hu ", ntohs(info->to[0]), ntohs(info->to[1]));
 172 }
 173
 174 struct iptables_target autofw
 175 = { NULL,
 176     "autofw",
 177     IPTABLES_VERSION,
 178     IPT_ALIGN(sizeof(struct ip_autofw_info)),
 179     IPT_ALIGN(sizeof(struct ip_autofw_info)),
 180     &help,
 181     &init,
 182     &parse,
 183     &final_check,
 184     &print,
 185     &save,
 186     opts
 187 };
 188
 189 void _init(void)
 190 {
 191         register_target(&autofw);
 192 }