| /* Shared library add-on to iptables to add simple load-balance support. */ |
| #include <stdio.h> |
| #include <netdb.h> |
| #include <string.h> |
| #include <stdlib.h> |
| #include <getopt.h> |
| #include <iptables.h> |
| #include <linux/netfilter_ipv4/ip_tables.h> |
| #include <linux/netfilter_ipv4/ip_nat_rule.h> |
| |
| #define BREAKUP_IP(x) (x)>>24, ((x)>>16) & 0xFF, ((x)>>8) & 0xFF, (x) & 0xFF |
| |
| /* Function which prints out usage message. */ |
| static void |
| help(void) |
| { |
| printf( |
| "BALANCE v%s options:\n" |
| " --to-destination <ipaddr>-<ipaddr>\n" |
| " Addresses to map destination to.\n", |
| IPTABLES_VERSION); |
| } |
| |
| static struct option opts[] = { |
| { "to-destination", 1, 0, '1' }, |
| { 0 } |
| }; |
| |
| /* Initialize the target. */ |
| static void |
| init(struct ipt_entry_target *t, unsigned int *nfcache) |
| { |
| struct ip_nat_multi_range *mr = (struct ip_nat_multi_range *)t->data; |
| |
| /* Actually, it's 0, but it's ignored at the moment. */ |
| mr->rangesize = 1; |
| |
| /* Can't cache this */ |
| *nfcache |= NFC_UNKNOWN; |
| } |
| |
| /* Parses range of IPs */ |
| static void |
| parse_to(char *arg, struct ip_nat_range *range) |
| { |
| char *dash; |
| struct in_addr *ip; |
| |
| range->flags |= IP_NAT_RANGE_MAP_IPS; |
| dash = strchr(arg, '-'); |
| if (dash) |
| *dash = '\0'; |
| else |
| exit_error(PARAMETER_PROBLEM, "Bad IP range `%s'\n", arg); |
| |
| ip = dotted_to_addr(arg); |
| if (!ip) |
| exit_error(PARAMETER_PROBLEM, "Bad IP address `%s'\n", |
| arg); |
| range->min_ip = ip->s_addr; |
| ip = dotted_to_addr(dash+1); |
| if (!ip) |
| exit_error(PARAMETER_PROBLEM, "Bad IP address `%s'\n", |
| dash+1); |
| range->max_ip = ip->s_addr; |
| } |
| |
| /* Function which parses command options; returns true if it |
| ate an option */ |
| static int |
| parse(int c, char **argv, int invert, unsigned int *flags, |
| const struct ipt_entry *entry, |
| struct ipt_entry_target **target) |
| { |
| struct ip_nat_multi_range *mr |
| = (struct ip_nat_multi_range *)(*target)->data; |
| |
| switch (c) { |
| case '1': |
| if (check_inverse(optarg, &invert, NULL, 0)) |
| exit_error(PARAMETER_PROBLEM, |
| "Unexpected `!' after --to-destination"); |
| |
| parse_to(optarg, &mr->range[0]); |
| *flags = 1; |
| return 1; |
| |
| default: |
| return 0; |
| } |
| } |
| |
| /* Final check; need --to-dest. */ |
| static void final_check(unsigned int flags) |
| { |
| if (!flags) |
| exit_error(PARAMETER_PROBLEM, |
| "BALANCE needs --to-destination"); |
| } |
| |
| /* Prints out the targinfo. */ |
| static void |
| print(const struct ipt_ip *ip, |
| const struct ipt_entry_target *target, |
| int numeric) |
| { |
| struct ip_nat_multi_range *mr |
| = (struct ip_nat_multi_range *)target->data; |
| struct ip_nat_range *r = &mr->range[0]; |
| struct in_addr a; |
| |
| a.s_addr = r->min_ip; |
| |
| printf("balance %s", addr_to_dotted(&a)); |
| a.s_addr = r->max_ip; |
| printf("-%s ", addr_to_dotted(&a)); |
| } |
| |
| /* Saves the union ipt_targinfo in parsable form to stdout. */ |
| static void |
| save(const struct ipt_ip *ip, const struct ipt_entry_target *target) |
| { |
| struct ip_nat_multi_range *mr |
| = (struct ip_nat_multi_range *)target->data; |
| struct ip_nat_range *r = &mr->range[0]; |
| struct in_addr a; |
| |
| a.s_addr = r->min_ip; |
| printf("--to-destination %s", addr_to_dotted(&a)); |
| a.s_addr = r->max_ip; |
| printf("-%s ", addr_to_dotted(&a)); |
| } |
| |
| static |
| struct iptables_target balance |
| = { NULL, |
| "BALANCE", |
| IPTABLES_VERSION, |
| IPT_ALIGN(sizeof(struct ip_nat_multi_range)), |
| IPT_ALIGN(sizeof(struct ip_nat_multi_range)), |
| &help, |
| &init, |
| &parse, |
| &final_check, |
| &print, |
| &save, |
| opts |
| }; |
| |
| void _init(void) |
| { |
| register_target(&balance); |
| } |