Svenning Soerensen | b2f9cb7 | 2001-05-03 01:15:09 +0000 | [diff] [blame] | 1 | /* Shared library add-on to iptables to add static NAT support. |
| 2 | Author: Svenning Soerensen <svenning@post5.tele.dk> |
| 3 | */ |
| 4 | |
| 5 | #include <stdio.h> |
| 6 | #include <netdb.h> |
| 7 | #include <string.h> |
| 8 | #include <stdlib.h> |
| 9 | #include <getopt.h> |
Jan Engelhardt | 5d9678a | 2008-11-20 10:15:35 +0100 | [diff] [blame] | 10 | #include <xtables.h> |
Svenning Soerensen | b2f9cb7 | 2001-05-03 01:15:09 +0000 | [diff] [blame] | 11 | #include <linux/netfilter_ipv4/ip_tables.h> |
Patrick McHardy | 40d5475 | 2007-04-18 07:00:36 +0000 | [diff] [blame] | 12 | #include <linux/netfilter/nf_nat.h> |
Svenning Soerensen | b2f9cb7 | 2001-05-03 01:15:09 +0000 | [diff] [blame] | 13 | |
| 14 | #define MODULENAME "NETMAP" |
| 15 | |
Jan Engelhardt | 1d5b63d | 2007-10-04 16:29:00 +0000 | [diff] [blame] | 16 | static const struct option NETMAP_opts[] = { |
Patrick McHardy | 500f483 | 2007-09-08 15:59:04 +0000 | [diff] [blame] | 17 | { "to", 1, NULL, '1' }, |
Max Kellermann | 9ee386a | 2008-01-29 13:48:05 +0000 | [diff] [blame] | 18 | { .name = NULL } |
Svenning Soerensen | b2f9cb7 | 2001-05-03 01:15:09 +0000 | [diff] [blame] | 19 | }; |
| 20 | |
Jan Engelhardt | 1d5b63d | 2007-10-04 16:29:00 +0000 | [diff] [blame] | 21 | static void NETMAP_help(void) |
Svenning Soerensen | b2f9cb7 | 2001-05-03 01:15:09 +0000 | [diff] [blame] | 22 | { |
Jan Engelhardt | 8b7c64d | 2008-04-15 11:48:25 +0200 | [diff] [blame] | 23 | printf(MODULENAME" target options:\n" |
Svenning Soerensen | b2f9cb7 | 2001-05-03 01:15:09 +0000 | [diff] [blame] | 24 | " --%s address[/mask]\n" |
| 25 | " Network address to map to.\n\n", |
Jan Engelhardt | 8b7c64d | 2008-04-15 11:48:25 +0200 | [diff] [blame] | 26 | NETMAP_opts[0].name); |
Svenning Soerensen | b2f9cb7 | 2001-05-03 01:15:09 +0000 | [diff] [blame] | 27 | } |
| 28 | |
| 29 | static u_int32_t |
| 30 | bits2netmask(int bits) |
| 31 | { |
| 32 | u_int32_t netmask, bm; |
| 33 | |
| 34 | if (bits >= 32 || bits < 0) |
| 35 | return(~0); |
| 36 | for (netmask = 0, bm = 0x80000000; bits; bits--, bm >>= 1) |
| 37 | netmask |= bm; |
| 38 | return htonl(netmask); |
| 39 | } |
| 40 | |
| 41 | static int |
| 42 | netmask2bits(u_int32_t netmask) |
| 43 | { |
| 44 | u_int32_t bm; |
| 45 | int bits; |
| 46 | |
| 47 | netmask = ntohl(netmask); |
| 48 | for (bits = 0, bm = 0x80000000; netmask & bm; netmask <<= 1) |
| 49 | bits++; |
| 50 | if (netmask) |
| 51 | return -1; /* holes in netmask */ |
| 52 | return bits; |
| 53 | } |
| 54 | |
Jan Engelhardt | 1d5b63d | 2007-10-04 16:29:00 +0000 | [diff] [blame] | 55 | static void NETMAP_init(struct xt_entry_target *t) |
Svenning Soerensen | b2f9cb7 | 2001-05-03 01:15:09 +0000 | [diff] [blame] | 56 | { |
| 57 | struct ip_nat_multi_range *mr = (struct ip_nat_multi_range *)t->data; |
| 58 | |
| 59 | /* Actually, it's 0, but it's ignored at the moment. */ |
| 60 | mr->rangesize = 1; |
| 61 | |
Svenning Soerensen | b2f9cb7 | 2001-05-03 01:15:09 +0000 | [diff] [blame] | 62 | } |
| 63 | |
| 64 | /* Parses network address */ |
| 65 | static void |
| 66 | parse_to(char *arg, struct ip_nat_range *range) |
| 67 | { |
| 68 | char *slash; |
Jan Engelhardt | bd94384 | 2008-01-20 13:38:08 +0000 | [diff] [blame] | 69 | const struct in_addr *ip; |
Svenning Soerensen | b2f9cb7 | 2001-05-03 01:15:09 +0000 | [diff] [blame] | 70 | u_int32_t netmask; |
Harald Welte | b471976 | 2001-07-23 02:14:22 +0000 | [diff] [blame] | 71 | unsigned int bits; |
Svenning Soerensen | b2f9cb7 | 2001-05-03 01:15:09 +0000 | [diff] [blame] | 72 | |
| 73 | range->flags |= IP_NAT_RANGE_MAP_IPS; |
| 74 | slash = strchr(arg, '/'); |
| 75 | if (slash) |
| 76 | *slash = '\0'; |
| 77 | |
Jan Engelhardt | 1e01b0b | 2009-01-30 04:20:32 +0100 | [diff] [blame] | 78 | ip = xtables_numeric_to_ipaddr(arg); |
Svenning Soerensen | b2f9cb7 | 2001-05-03 01:15:09 +0000 | [diff] [blame] | 79 | if (!ip) |
| 80 | exit_error(PARAMETER_PROBLEM, "Bad IP address `%s'\n", |
| 81 | arg); |
| 82 | range->min_ip = ip->s_addr; |
| 83 | if (slash) { |
| 84 | if (strchr(slash+1, '.')) { |
Jan Engelhardt | 1e01b0b | 2009-01-30 04:20:32 +0100 | [diff] [blame] | 85 | ip = xtables_numeric_to_ipmask(slash+1); |
Svenning Soerensen | b2f9cb7 | 2001-05-03 01:15:09 +0000 | [diff] [blame] | 86 | if (!ip) |
| 87 | exit_error(PARAMETER_PROBLEM, "Bad netmask `%s'\n", |
| 88 | slash+1); |
| 89 | netmask = ip->s_addr; |
| 90 | } |
| 91 | else { |
Jan Engelhardt | 5f2922c | 2009-01-27 18:43:01 +0100 | [diff] [blame] | 92 | if (!xtables_strtoui(slash+1, NULL, &bits, 0, 32)) |
Svenning Soerensen | b2f9cb7 | 2001-05-03 01:15:09 +0000 | [diff] [blame] | 93 | exit_error(PARAMETER_PROBLEM, "Bad netmask `%s'\n", |
| 94 | slash+1); |
| 95 | netmask = bits2netmask(bits); |
| 96 | } |
| 97 | /* Don't allow /0 (/1 is probably insane, too) */ |
| 98 | if (netmask == 0) |
| 99 | exit_error(PARAMETER_PROBLEM, "Netmask needed\n"); |
| 100 | } |
| 101 | else |
| 102 | netmask = ~0; |
| 103 | |
| 104 | if (range->min_ip & ~netmask) { |
| 105 | if (slash) |
| 106 | *slash = '/'; |
| 107 | exit_error(PARAMETER_PROBLEM, "Bad network address `%s'\n", |
| 108 | arg); |
| 109 | } |
| 110 | range->max_ip = range->min_ip | ~netmask; |
| 111 | } |
| 112 | |
Jan Engelhardt | 1d5b63d | 2007-10-04 16:29:00 +0000 | [diff] [blame] | 113 | static int NETMAP_parse(int c, char **argv, int invert, unsigned int *flags, |
| 114 | const void *entry, struct xt_entry_target **target) |
Svenning Soerensen | b2f9cb7 | 2001-05-03 01:15:09 +0000 | [diff] [blame] | 115 | { |
| 116 | struct ip_nat_multi_range *mr |
| 117 | = (struct ip_nat_multi_range *)(*target)->data; |
| 118 | |
| 119 | switch (c) { |
| 120 | case '1': |
Harald Welte | b77f1da | 2002-03-14 11:35:58 +0000 | [diff] [blame] | 121 | if (check_inverse(optarg, &invert, NULL, 0)) |
Svenning Soerensen | b2f9cb7 | 2001-05-03 01:15:09 +0000 | [diff] [blame] | 122 | exit_error(PARAMETER_PROBLEM, |
Jan Engelhardt | 1d5b63d | 2007-10-04 16:29:00 +0000 | [diff] [blame] | 123 | "Unexpected `!' after --%s", NETMAP_opts[0].name); |
Svenning Soerensen | b2f9cb7 | 2001-05-03 01:15:09 +0000 | [diff] [blame] | 124 | |
| 125 | parse_to(optarg, &mr->range[0]); |
| 126 | *flags = 1; |
| 127 | return 1; |
| 128 | |
| 129 | default: |
| 130 | return 0; |
| 131 | } |
| 132 | } |
| 133 | |
Jan Engelhardt | 1d5b63d | 2007-10-04 16:29:00 +0000 | [diff] [blame] | 134 | static void NETMAP_check(unsigned int flags) |
Svenning Soerensen | b2f9cb7 | 2001-05-03 01:15:09 +0000 | [diff] [blame] | 135 | { |
| 136 | if (!flags) |
| 137 | exit_error(PARAMETER_PROBLEM, |
Jan Engelhardt | 1d5b63d | 2007-10-04 16:29:00 +0000 | [diff] [blame] | 138 | MODULENAME" needs --%s", NETMAP_opts[0].name); |
Svenning Soerensen | b2f9cb7 | 2001-05-03 01:15:09 +0000 | [diff] [blame] | 139 | } |
| 140 | |
Jan Engelhardt | 1d5b63d | 2007-10-04 16:29:00 +0000 | [diff] [blame] | 141 | static void NETMAP_print(const void *ip, const struct xt_entry_target *target, |
| 142 | int numeric) |
Svenning Soerensen | b2f9cb7 | 2001-05-03 01:15:09 +0000 | [diff] [blame] | 143 | { |
| 144 | struct ip_nat_multi_range *mr |
| 145 | = (struct ip_nat_multi_range *)target->data; |
| 146 | struct ip_nat_range *r = &mr->range[0]; |
| 147 | struct in_addr a; |
| 148 | int bits; |
| 149 | |
| 150 | a.s_addr = r->min_ip; |
Jan Engelhardt | e44ea7f | 2009-01-30 03:55:09 +0100 | [diff] [blame] | 151 | printf("%s", xtables_ipaddr_to_numeric(&a)); |
Svenning Soerensen | b2f9cb7 | 2001-05-03 01:15:09 +0000 | [diff] [blame] | 152 | a.s_addr = ~(r->min_ip ^ r->max_ip); |
| 153 | bits = netmask2bits(a.s_addr); |
| 154 | if (bits < 0) |
Jan Engelhardt | e44ea7f | 2009-01-30 03:55:09 +0100 | [diff] [blame] | 155 | printf("/%s", xtables_ipaddr_to_numeric(&a)); |
Svenning Soerensen | b2f9cb7 | 2001-05-03 01:15:09 +0000 | [diff] [blame] | 156 | else |
| 157 | printf("/%d", bits); |
| 158 | } |
| 159 | |
Jan Engelhardt | 1d5b63d | 2007-10-04 16:29:00 +0000 | [diff] [blame] | 160 | static void NETMAP_save(const void *ip, const struct xt_entry_target *target) |
Svenning Soerensen | b2f9cb7 | 2001-05-03 01:15:09 +0000 | [diff] [blame] | 161 | { |
Jan Engelhardt | 1d5b63d | 2007-10-04 16:29:00 +0000 | [diff] [blame] | 162 | printf("--%s ", NETMAP_opts[0].name); |
| 163 | NETMAP_print(ip, target, 0); |
Svenning Soerensen | b2f9cb7 | 2001-05-03 01:15:09 +0000 | [diff] [blame] | 164 | } |
| 165 | |
Jan Engelhardt | 8b7c64d | 2008-04-15 11:48:25 +0200 | [diff] [blame] | 166 | static struct xtables_target netmap_tg_reg = { |
Pablo Neira | 8caee8b | 2004-12-28 13:11:59 +0000 | [diff] [blame] | 167 | .name = MODULENAME, |
Jan Engelhardt | 8b7c64d | 2008-04-15 11:48:25 +0200 | [diff] [blame] | 168 | .version = XTABLES_VERSION, |
Jan Engelhardt | 03d9948 | 2008-11-18 12:27:54 +0100 | [diff] [blame] | 169 | .family = NFPROTO_IPV4, |
Jan Engelhardt | 8b7c64d | 2008-04-15 11:48:25 +0200 | [diff] [blame] | 170 | .size = XT_ALIGN(sizeof(struct ip_nat_multi_range)), |
| 171 | .userspacesize = XT_ALIGN(sizeof(struct ip_nat_multi_range)), |
Jan Engelhardt | 1d5b63d | 2007-10-04 16:29:00 +0000 | [diff] [blame] | 172 | .help = NETMAP_help, |
| 173 | .init = NETMAP_init, |
| 174 | .parse = NETMAP_parse, |
| 175 | .final_check = NETMAP_check, |
| 176 | .print = NETMAP_print, |
| 177 | .save = NETMAP_save, |
| 178 | .extra_opts = NETMAP_opts, |
Svenning Soerensen | b2f9cb7 | 2001-05-03 01:15:09 +0000 | [diff] [blame] | 179 | }; |
| 180 | |
| 181 | void _init(void) |
| 182 | { |
Jan Engelhardt | 8b7c64d | 2008-04-15 11:48:25 +0200 | [diff] [blame] | 183 | xtables_register_target(&netmap_tg_reg); |
Svenning Soerensen | b2f9cb7 | 2001-05-03 01:15:09 +0000 | [diff] [blame] | 184 | } |