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

   1 /* Shared library add-on to iptables to add simple load-balance support. */
   2 #include <stdio.h>
   3 #include <netdb.h>
   4 #include <string.h>
   5 #include <stdlib.h>
   6 #include <getopt.h>
   7 #include <iptables.h>
   8 #include <linux/netfilter_ipv4/ip_tables.h>
   9 #include <linux/netfilter_ipv4/ip_nat_rule.h>
  10
  11 #define BREAKUP_IP(x) (x)>>24, ((x)>>16) & 0xFF, ((x)>>8) & 0xFF, (x) & 0xFF
  12
  13 /* Function which prints out usage message. */
  14 static void
  15 help(void)
  16 {
  17         printf(
  18 "BALANCE v%s options:\n"
  19 " --to-destination <ipaddr>-<ipaddr>\n"
  20 "                               Addresses to map destination to.\n",
  21 IPTABLES_VERSION);
  22 }
  23
  24 static struct option opts[] = {
  25         { "to-destination", 1, 0, '1' },
  26         { 0 }
  27 };
  28
  29 /* Initialize the target. */
  30 static void
  31 init(struct ipt_entry_target *t, unsigned int *nfcache)
  32 {
  33         struct ip_nat_multi_range *mr = (struct ip_nat_multi_range *)t->data;
  34
  35         /* Actually, it's 0, but it's ignored at the moment. */
  36         mr->rangesize = 1;
  37
  38 }
  39
  40 /* Parses range of IPs */
  41 static void
  42 parse_to(char *arg, struct ip_nat_range *range)
  43 {
  44         char *dash;
  45         struct in_addr *ip;
  46
  47         range->flags |= IP_NAT_RANGE_MAP_IPS;
  48         dash = strchr(arg, '-');
  49         if (dash)
  50                 *dash = '\0';
  51         else
  52                 exit_error(PARAMETER_PROBLEM, "Bad IP range `%s'\n", arg);
  53
  54         ip = dotted_to_addr(arg);
  55         if (!ip)
  56                 exit_error(PARAMETER_PROBLEM, "Bad IP address `%s'\n",
  57                            arg);
  58         range->min_ip = ip->s_addr;
  59         ip = dotted_to_addr(dash+1);
  60         if (!ip)
  61                 exit_error(PARAMETER_PROBLEM, "Bad IP address `%s'\n",
  62                            dash+1);
  63         range->max_ip = ip->s_addr;
  64 }
  65
  66 /* Function which parses command options; returns true if it
  67    ate an option */
  68 static int
  69 parse(int c, char **argv, int invert, unsigned int *flags,
  70       const struct ipt_entry *entry,
  71       struct ipt_entry_target **target)
  72 {
  73         struct ip_nat_multi_range *mr
  74                 = (struct ip_nat_multi_range *)(*target)->data;
  75
  76         switch (c) {
  77         case '1':
  78                 if (check_inverse(optarg, &invert, NULL, 0))
  79                         exit_error(PARAMETER_PROBLEM,
  80                                    "Unexpected `!' after --to-destination");
  81
  82                 parse_to(optarg, &mr->range[0]);
  83                 *flags = 1;
  84                 return 1;
  85
  86         default:
  87                 return 0;
  88         }
  89 }
  90
  91 /* Final check; need --to-dest. */
  92 static void final_check(unsigned int flags)
  93 {
  94         if (!flags)
  95                 exit_error(PARAMETER_PROBLEM,
  96                            "BALANCE needs --to-destination");
  97 }
  98
  99 /* Prints out the targinfo. */
 100 static void
 101 print(const struct ipt_ip *ip,
 102       const struct ipt_entry_target *target,
 103       int numeric)
 104 {
 105         struct ip_nat_multi_range *mr
 106                 = (struct ip_nat_multi_range *)target->data;
 107         struct ip_nat_range *r = &mr->range[0];
 108         struct in_addr a;
 109
 110         a.s_addr = r->min_ip;
 111
 112         printf("balance %s", addr_to_dotted(&a));
 113         a.s_addr = r->max_ip;
 114         printf("-%s ", addr_to_dotted(&a));
 115 }
 116
 117 /* Saves the union ipt_targinfo in parsable form to stdout. */
 118 static void
 119 save(const struct ipt_ip *ip, const struct ipt_entry_target *target)
 120 {
 121         struct ip_nat_multi_range *mr
 122                 = (struct ip_nat_multi_range *)target->data;
 123         struct ip_nat_range *r = &mr->range[0];
 124         struct in_addr a;
 125
 126         a.s_addr = r->min_ip;
 127         printf("--to-destination %s", addr_to_dotted(&a));
 128         a.s_addr = r->max_ip;
 129         printf("-%s ", addr_to_dotted(&a));
 130 }
 131
 132 static struct iptables_target balance = {
 133         .next           = NULL,
 134         .name           = "BALANCE",
 135         .version        = IPTABLES_VERSION,
 136         .size           = IPT_ALIGN(sizeof(struct ip_nat_multi_range)),
 137         .userspacesize  = IPT_ALIGN(sizeof(struct ip_nat_multi_range)),
 138         .help           = &help,
 139         .init           = &init,
 140         .parse          = &parse,
 141         .final_check    = &final_check,
 142         .print          = &print,
 143         .save           = &save,
 144         .extra_opts     = opts
 145 };
 146
 147 void _init(void)
 148 {
 149         register_target(&balance);
 150 }