1 /* Shared library add-on to iptables to add simple load-balance support. */
8 #include <linux/netfilter_ipv4/ip_tables.h>
9 #include <linux/netfilter_ipv4/ip_nat_rule.h>
11 #define BREAKUP_IP(x) (x)>>24, ((x)>>16) & 0xFF, ((x)>>8) & 0xFF, (x) & 0xFF
13 /* Function which prints out usage message. */
18 "BALANCE v%s options:\n"
19 " --to-destination <ipaddr>-<ipaddr>\n"
20 " Addresses to map destination to.\n",
24 static struct option opts[] = {
25 { "to-destination", 1, 0, '1' },
29 /* Initialize the target. */
31 init(struct ipt_entry_target *t, unsigned int *nfcache)
33 struct ip_nat_multi_range *mr = (struct ip_nat_multi_range *)t->data;
35 /* Actually, it's 0, but it's ignored at the moment. */
40 /* Parses range of IPs */
42 parse_to(char *arg, struct ip_nat_range *range)
47 range->flags |= IP_NAT_RANGE_MAP_IPS;
48 dash = strchr(arg, '-');
52 exit_error(PARAMETER_PROBLEM, "Bad IP range `%s'\n", arg);
54 ip = dotted_to_addr(arg);
56 exit_error(PARAMETER_PROBLEM, "Bad IP address `%s'\n",
58 range->min_ip = ip->s_addr;
59 ip = dotted_to_addr(dash+1);
61 exit_error(PARAMETER_PROBLEM, "Bad IP address `%s'\n",
63 range->max_ip = ip->s_addr;
66 /* Function which parses command options; returns true if it
69 parse(int c, char **argv, int invert, unsigned int *flags,
70 const struct ipt_entry *entry,
71 struct ipt_entry_target **target)
73 struct ip_nat_multi_range *mr
74 = (struct ip_nat_multi_range *)(*target)->data;
78 if (check_inverse(optarg, &invert, NULL, 0))
79 exit_error(PARAMETER_PROBLEM,
80 "Unexpected `!' after --to-destination");
82 parse_to(optarg, &mr->range[0]);
91 /* Final check; need --to-dest. */
92 static void final_check(unsigned int flags)
95 exit_error(PARAMETER_PROBLEM,
96 "BALANCE needs --to-destination");
99 /* Prints out the targinfo. */
101 print(const struct ipt_ip *ip,
102 const struct ipt_entry_target *target,
105 struct ip_nat_multi_range *mr
106 = (struct ip_nat_multi_range *)target->data;
107 struct ip_nat_range *r = &mr->range[0];
110 a.s_addr = r->min_ip;
112 printf("balance %s", addr_to_dotted(&a));
113 a.s_addr = r->max_ip;
114 printf("-%s ", addr_to_dotted(&a));
117 /* Saves the union ipt_targinfo in parsable form to stdout. */
119 save(const struct ipt_ip *ip, const struct ipt_entry_target *target)
121 struct ip_nat_multi_range *mr
122 = (struct ip_nat_multi_range *)target->data;
123 struct ip_nat_range *r = &mr->range[0];
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));
132 static struct iptables_target 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)),
141 .final_check = &final_check,
149 register_target(&balance);