| Rusty Russell | d4d9196 | 2000-10-23 06:41:41 +0000 | [diff] [blame] | 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 | NETFILTER_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 | /* Can't cache this */ |
| 39 | *nfcache |= NFC_UNKNOWN; |
| 40 | } |
| 41 | |
| 42 | /* Parses range of IPs */ |
| 43 | static void |
| 44 | parse_to(char *arg, struct ip_nat_range *range) |
| 45 | { |
| 46 | char *dash; |
| 47 | struct in_addr *ip; |
| 48 | |
| 49 | range->flags |= IP_NAT_RANGE_MAP_IPS; |
| 50 | dash = strchr(arg, '-'); |
| 51 | if (dash) |
| 52 | *dash = '\0'; |
| 53 | else |
| 54 | exit_error(PARAMETER_PROBLEM, "Bad IP range `%s'\n", arg); |
| 55 | |
| 56 | ip = dotted_to_addr(arg); |
| 57 | if (!ip) |
| 58 | exit_error(PARAMETER_PROBLEM, "Bad IP address `%s'\n", |
| 59 | arg); |
| 60 | range->min_ip = ip->s_addr; |
| 61 | ip = dotted_to_addr(dash+1); |
| 62 | if (!ip) |
| 63 | exit_error(PARAMETER_PROBLEM, "Bad IP address `%s'\n", |
| 64 | dash+1); |
| 65 | range->max_ip = ip->s_addr; |
| 66 | } |
| 67 | |
| 68 | /* Function which parses command options; returns true if it |
| 69 | ate an option */ |
| 70 | static int |
| 71 | parse(int c, char **argv, int invert, unsigned int *flags, |
| 72 | const struct ipt_entry *entry, |
| 73 | struct ipt_entry_target **target) |
| 74 | { |
| 75 | struct ip_nat_multi_range *mr |
| 76 | = (struct ip_nat_multi_range *)(*target)->data; |
| 77 | |
| 78 | switch (c) { |
| 79 | case '1': |
| 80 | if (check_inverse(optarg, &invert)) |
| 81 | exit_error(PARAMETER_PROBLEM, |
| 82 | "Unexpected `!' after --to-destination"); |
| 83 | |
| 84 | parse_to(optarg, &mr->range[0]); |
| 85 | *flags = 1; |
| 86 | return 1; |
| 87 | |
| 88 | default: |
| 89 | return 0; |
| 90 | } |
| 91 | } |
| 92 | |
| 93 | /* Final check; need --to-dest. */ |
| 94 | static void final_check(unsigned int flags) |
| 95 | { |
| 96 | if (!flags) |
| 97 | exit_error(PARAMETER_PROBLEM, |
| 98 | "BALANCE needs --to-destination"); |
| 99 | } |
| 100 | |
| 101 | /* Prints out the targinfo. */ |
| 102 | static void |
| 103 | print(const struct ipt_ip *ip, |
| 104 | const struct ipt_entry_target *target, |
| 105 | int numeric) |
| 106 | { |
| 107 | struct ip_nat_multi_range *mr |
| 108 | = (struct ip_nat_multi_range *)target->data; |
| 109 | struct ip_nat_range *r = &mr->range[0]; |
| 110 | struct in_addr a; |
| 111 | |
| 112 | a.s_addr = r->min_ip; |
| 113 | |
| 114 | printf("balance %s", addr_to_dotted(&a)); |
| 115 | a.s_addr = r->max_ip; |
| 116 | printf("-%s ", addr_to_dotted(&a)); |
| 117 | } |
| 118 | |
| 119 | /* Saves the union ipt_targinfo in parsable form to stdout. */ |
| 120 | static void |
| 121 | save(const struct ipt_ip *ip, const struct ipt_entry_target *target) |
| 122 | { |
| 123 | struct ip_nat_multi_range *mr |
| 124 | = (struct ip_nat_multi_range *)target->data; |
| 125 | struct ip_nat_range *r = &mr->range[0]; |
| 126 | struct in_addr a; |
| 127 | |
| 128 | a.s_addr = r->min_ip; |
| 129 | printf("--to-destination %s", addr_to_dotted(&a)); |
| 130 | a.s_addr = r->max_ip; |
| 131 | printf("-%s ", addr_to_dotted(&a)); |
| 132 | } |
| 133 | |
| 134 | struct iptables_target balance |
| 135 | = { NULL, |
| 136 | "BALANCE", |
| 137 | NETFILTER_VERSION, |
| 138 | IPT_ALIGN(sizeof(struct ip_nat_multi_range)), |
| 139 | IPT_ALIGN(sizeof(struct ip_nat_multi_range)), |
| 140 | &help, |
| 141 | &init, |
| 142 | &parse, |
| 143 | &final_check, |
| 144 | &print, |
| 145 | &save, |
| 146 | opts |
| 147 | }; |
| 148 | |
| 149 | void _init(void) |
| 150 | { |
| 151 | register_target(&balance); |
| 152 | } |